diff --git a/sqlite/sqlite3.c b/sqlite/sqlite3.c
index 6b6e919e7..55039b963 100755
--- a/sqlite/sqlite3.c
+++ b/sqlite/sqlite3.c
@@ -1,23 +1,21 @@
 /******************************************************************************
 ** This file is an amalgamation of many separate C source files from SQLite
-** version 3.6.10.  By combining all the individual C code files into this 
-** single large file, the entire code can be compiled as a one translation
+** version 3.7.14.1.  By combining all the individual C code files into this 
+** single large file, the entire code can be compiled as a single translation
 ** unit.  This allows many compilers to do optimizations that would not be
 ** possible if the files were compiled separately.  Performance improvements
-** of 5% are more are commonly seen when SQLite is compiled as a single
+** of 5% or more are commonly seen when SQLite is compiled as a single
 ** translation unit.
 **
 ** This file is all you need to compile SQLite.  To use SQLite in other
 ** programs, you need this file and the "sqlite3.h" header file that defines
 ** the programming interface to the SQLite library.  (If you do not have 
-** the "sqlite3.h" header file at hand, you will find a copy in the first
-** 6736 lines past this header comment.)  Additional code files may be
-** needed if you want a wrapper to interface SQLite with your choice of
-** programming language.  The code for the "sqlite3" command-line shell
-** is also in a separate file.  This file contains only code for the core
-** SQLite library.
-**
-** This amalgamation was generated on 2009-01-15 16:00:39 UTC.
+** the "sqlite3.h" header file at hand, you will find a copy embedded within
+** the text of this file.  Search for "Begin file sqlite3.h" to find the start
+** of the embedded sqlite3.h header file.) Additional code files may be needed
+** if you want a wrapper to interface SQLite with your choice of programming
+** language. The code for the "sqlite3" command-line shell is also in a
+** separate file. This file contains only code for the core SQLite library.
 */
 #define SQLITE_CORE 1
 #define SQLITE_AMALGAMATION 1
@@ -41,11 +39,37 @@
 *************************************************************************
 ** Internal interface definitions for SQLite.
 **
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _SQLITEINT_H_
 #define _SQLITEINT_H_
 
+/*
+** These #defines should enable >2GB file support on POSIX if the
+** underlying operating system supports it.  If the OS lacks
+** large file support, or if the OS is windows, these should be no-ops.
+**
+** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
+** system #includes.  Hence, this block of code must be the very first
+** code in all source files.
+**
+** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
+** on the compiler command line.  This is necessary if you are compiling
+** on a recent machine (ex: Red Hat 7.2) but you want your code to work
+** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
+** without this option, LFS is enable.  But LFS does not exist in the kernel
+** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
+** portability you should omit LFS.
+**
+** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
+*/
+#ifndef SQLITE_DISABLE_LFS
+# define _LARGE_FILE       1
+# ifndef _FILE_OFFSET_BITS
+#   define _FILE_OFFSET_BITS 64
+# endif
+# define _LARGEFILE_SOURCE 1
+#endif
+
 /*
 ** Include the configuration header output by 'configure' if we're using the
 ** autoconf-based build
@@ -69,8 +93,6 @@
 *************************************************************************
 ** 
 ** This file defines various limits of what SQLite can process.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -168,9 +190,17 @@
 # define SQLITE_DEFAULT_TEMP_CACHE_SIZE  500
 #endif
 
+/*
+** The default number of frames to accumulate in the log file before
+** checkpointing the database in WAL mode.
+*/
+#ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT
+# define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT  1000
+#endif
+
 /*
 ** The maximum number of attached databases.  This must be between 0
-** and 30.  The upper bound on 30 is because a 32-bit integer bitmap
+** and 62.  The upper bound on 62 is because a 64-bit integer bitmap
 ** is used internally to track attached databases.
 */
 #ifndef SQLITE_MAX_ATTACHED
@@ -185,20 +215,21 @@
 # define SQLITE_MAX_VARIABLE_NUMBER 999
 #endif
 
-/* Maximum page size.  The upper bound on this value is 32768.  This a limit
-** imposed by the necessity of storing the value in a 2-byte unsigned integer
-** and the fact that the page size must be a power of 2.
+/* Maximum page size.  The upper bound on this value is 65536.  This a limit
+** imposed by the use of 16-bit offsets within each page.
 **
-** If this limit is changed, then the compiled library is technically
-** incompatible with an SQLite library compiled with a different limit. If
-** a process operating on a database with a page-size of 65536 bytes 
-** crashes, then an instance of SQLite compiled with the default page-size 
-** limit will not be able to rollback the aborted transaction. This could
-** lead to database corruption.
+** Earlier versions of SQLite allowed the user to change this value at
+** compile time. This is no longer permitted, on the grounds that it creates
+** a library that is technically incompatible with an SQLite library 
+** compiled with a different limit. If a process operating on a database 
+** with a page-size of 65536 bytes crashes, then an instance of SQLite 
+** compiled with the default page-size limit will not be able to rollback 
+** the aborted transaction. This could lead to database corruption.
 */
-#ifndef SQLITE_MAX_PAGE_SIZE
-# define SQLITE_MAX_PAGE_SIZE 32768
+#ifdef SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_MAX_PAGE_SIZE
 #endif
+#define SQLITE_MAX_PAGE_SIZE 65536
 
 
 /*
@@ -247,6 +278,17 @@
 # define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
 #endif
 
+/*
+** Maximum depth of recursion for triggers.
+**
+** A value of 1 means that a trigger program will not be able to itself
+** fire any triggers. A value of 0 means that no trigger programs at all 
+** may be executed.
+*/
+#ifndef SQLITE_MAX_TRIGGER_DEPTH
+# define SQLITE_MAX_TRIGGER_DEPTH 1000
+#endif
+
 /************** End of sqliteLimit.h *****************************************/
 /************** Continuing where we left off in sqliteInt.h ******************/
 
@@ -275,63 +317,62 @@
 #endif
 
 /*
- * This macro is used to "hide" some ugliness in casting an int
- * value to a ptr value under the MSVC 64-bit compiler.   Casting
- * non 64-bit values to ptr types results in a "hard" error with 
- * the MSVC 64-bit compiler which this attempts to avoid.  
- *
- * A simple compiler pragma or casting sequence could not be found
- * to correct this in all situations, so this macro was introduced.
- *
- * It could be argued that the intptr_t type could be used in this
- * case, but that type is not available on all compilers, or 
- * requires the #include of specific headers which differs between
- * platforms.
- */
-#define SQLITE_INT_TO_PTR(X)   ((void*)&((char*)0)[X])
-#define SQLITE_PTR_TO_INT(X)   ((int)(((char*)X)-(char*)0))
-
-/*
-** These #defines should enable >2GB file support on POSIX if the
-** underlying operating system supports it.  If the OS lacks
-** large file support, or if the OS is windows, these should be no-ops.
+** The following macros are used to cast pointers to integers and
+** integers to pointers.  The way you do this varies from one compiler
+** to the next, so we have developed the following set of #if statements
+** to generate appropriate macros for a wide range of compilers.
 **
-** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
-** system #includes.  Hence, this block of code must be the very first
-** code in all source files.
+** The correct "ANSI" way to do this is to use the intptr_t type. 
+** Unfortunately, that typedef is not available on all compilers, or
+** if it is available, it requires an #include of specific headers
+** that vary from one machine to the next.
 **
-** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
-** on the compiler command line.  This is necessary if you are compiling
-** on a recent machine (ex: Red Hat 7.2) but you want your code to work
-** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
-** without this option, LFS is enable.  But LFS does not exist in the kernel
-** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
-** portability you should omit LFS.
-**
-** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
+** Ticket #3860:  The llvm-gcc-4.2 compiler from Apple chokes on
+** the ((void*)&((char*)0)[X]) construct.  But MSVC chokes on ((void*)(X)).
+** So we have to define the macros in different ways depending on the
+** compiler.
 */
-#ifndef SQLITE_DISABLE_LFS
-# define _LARGE_FILE       1
-# ifndef _FILE_OFFSET_BITS
-#   define _FILE_OFFSET_BITS 64
-# endif
-# define _LARGEFILE_SOURCE 1
+#if defined(__PTRDIFF_TYPE__)  /* This case should work for GCC */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(__PTRDIFF_TYPE__)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(__PTRDIFF_TYPE__)(X))
+#elif !defined(__GNUC__)       /* Works for compilers other than LLVM */
+# define SQLITE_INT_TO_PTR(X)  ((void*)&((char*)0)[X])
+# define SQLITE_PTR_TO_INT(X)  ((int)(((char*)X)-(char*)0))
+#elif defined(HAVE_STDINT_H)   /* Use this case if we have ANSI headers */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(intptr_t)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(intptr_t)(X))
+#else                          /* Generates a warning - but it always works */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(X))
 #endif
 
-
 /*
-** The SQLITE_THREADSAFE macro must be defined as either 0 or 1.
+** The SQLITE_THREADSAFE macro must be defined as 0, 1, or 2.
+** 0 means mutexes are permanently disable and the library is never
+** threadsafe.  1 means the library is serialized which is the highest
+** level of threadsafety.  2 means the libary is multithreaded - multiple
+** threads can use SQLite as long as no two threads try to use the same
+** database connection at the same time.
+**
 ** Older versions of SQLite used an optional THREADSAFE macro.
-** We support that for legacy
+** We support that for legacy.
 */
 #if !defined(SQLITE_THREADSAFE)
 #if defined(THREADSAFE)
 # define SQLITE_THREADSAFE THREADSAFE
 #else
-# define SQLITE_THREADSAFE 1
+# define SQLITE_THREADSAFE 1 /* IMP: R-07272-22309 */
 #endif
 #endif
 
+/*
+** Powersafe overwrite is on by default.  But can be turned off using
+** the -DSQLITE_POWERSAFE_OVERWRITE=0 command-line option.
+*/
+#ifndef SQLITE_POWERSAFE_OVERWRITE
+# define SQLITE_POWERSAFE_OVERWRITE 1
+#endif
+
 /*
 ** The SQLITE_DEFAULT_MEMSTATUS macro must be defined as either 0 or 1.
 ** It determines whether or not the features related to 
@@ -347,32 +388,42 @@
 ** specify which memory allocation subsystem to use.
 **
 **     SQLITE_SYSTEM_MALLOC          // Use normal system malloc()
+**     SQLITE_WIN32_MALLOC           // Use Win32 native heap API
+**     SQLITE_ZERO_MALLOC            // Use a stub allocator that always fails
 **     SQLITE_MEMDEBUG               // Debugging version of system malloc()
-**     SQLITE_MEMORY_SIZE            // internal allocator #1
-**     SQLITE_MMAP_HEAP_SIZE         // internal mmap() allocator
-**     SQLITE_POW2_MEMORY_SIZE       // internal power-of-two allocator
+**
+** On Windows, if the SQLITE_WIN32_MALLOC_VALIDATE macro is defined and the
+** assert() macro is enabled, each call into the Win32 native heap subsystem
+** will cause HeapValidate to be called.  If heap validation should fail, an
+** assertion will be triggered.
+**
+** (Historical note:  There used to be several other options, but we've
+** pared it down to just these three.)
 **
 ** If none of the above are defined, then set SQLITE_SYSTEM_MALLOC as
 ** the default.
 */
-#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)+\
-    defined(SQLITE_MEMORY_SIZE)+defined(SQLITE_MMAP_HEAP_SIZE)+\
-    defined(SQLITE_POW2_MEMORY_SIZE)>1
-# error "At most one of the following compile-time configuration options\
- is allows: SQLITE_SYSTEM_MALLOC, SQLITE_MEMDEBUG, SQLITE_MEMORY_SIZE,\
- SQLITE_MMAP_HEAP_SIZE, SQLITE_POW2_MEMORY_SIZE"
+#if defined(SQLITE_SYSTEM_MALLOC) \
+  + defined(SQLITE_WIN32_MALLOC) \
+  + defined(SQLITE_ZERO_MALLOC) \
+  + defined(SQLITE_MEMDEBUG)>1
+# error "Two or more of the following compile-time configuration options\
+ are defined but at most one is allowed:\
+ SQLITE_SYSTEM_MALLOC, SQLITE_WIN32_MALLOC, SQLITE_MEMDEBUG,\
+ SQLITE_ZERO_MALLOC"
 #endif
-#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)+\
-    defined(SQLITE_MEMORY_SIZE)+defined(SQLITE_MMAP_HEAP_SIZE)+\
-    defined(SQLITE_POW2_MEMORY_SIZE)==0
+#if defined(SQLITE_SYSTEM_MALLOC) \
+  + defined(SQLITE_WIN32_MALLOC) \
+  + defined(SQLITE_ZERO_MALLOC) \
+  + defined(SQLITE_MEMDEBUG)==0
 # define SQLITE_SYSTEM_MALLOC 1
 #endif
 
 /*
-** If SQLITE_MALLOC_SOFT_LIMIT is defined, then try to keep the
+** If SQLITE_MALLOC_SOFT_LIMIT is not zero, then try to keep the
 ** sizes of memory allocations below this value where possible.
 */
-#if defined(SQLITE_POW2_MEMORY_SIZE) && !defined(SQLITE_MALLOC_SOFT_LIMIT)
+#if !defined(SQLITE_MALLOC_SOFT_LIMIT)
 # define SQLITE_MALLOC_SOFT_LIMIT 1024
 #endif
 
@@ -401,15 +452,22 @@
 #endif
 
 /*
-** Many people are failing to set -DNDEBUG=1 when compiling SQLite.
-** Setting NDEBUG makes the code smaller and run faster.  So the following
-** lines are added to automatically set NDEBUG unless the -DSQLITE_DEBUG=1
-** option is set.  Thus NDEBUG becomes an opt-in rather than an opt-out
+** NDEBUG and SQLITE_DEBUG are opposites.  It should always be true that
+** defined(NDEBUG)==!defined(SQLITE_DEBUG).  If this is not currently true,
+** make it true by defining or undefining NDEBUG.
+**
+** Setting NDEBUG makes the code smaller and run faster by disabling the
+** number assert() statements in the code.  So we want the default action
+** to be for NDEBUG to be set and NDEBUG to be undefined only if SQLITE_DEBUG
+** is set.  Thus NDEBUG becomes an opt-in rather than an opt-out
 ** feature.
 */
 #if !defined(NDEBUG) && !defined(SQLITE_DEBUG) 
 # define NDEBUG 1
 #endif
+#if defined(NDEBUG) && defined(SQLITE_DEBUG)
+# undef NDEBUG
+#endif
 
 /*
 ** The testcase() macro is used to aid in coverage testing.  When 
@@ -443,6 +501,20 @@ SQLITE_PRIVATE   void sqlite3Coverage(int);
 # define TESTONLY(X)
 #endif
 
+/*
+** Sometimes we need a small amount of code such as a variable initialization
+** to setup for a later assert() statement.  We do not want this code to
+** appear when assert() is disabled.  The following macro is therefore
+** used to contain that setup code.  The "VVA" acronym stands for
+** "Verification, Validation, and Accreditation".  In other words, the
+** code within VVA_ONLY() will only run during verification processes.
+*/
+#ifndef NDEBUG
+# define VVA_ONLY(X)  X
+#else
+# define VVA_ONLY(X)
+#endif
+
 /*
 ** The ALWAYS and NEVER macros surround boolean expressions which 
 ** are intended to always be true or false, respectively.  Such
@@ -462,14 +534,20 @@ SQLITE_PRIVATE   void sqlite3Coverage(int);
 # define ALWAYS(X)      (1)
 # define NEVER(X)       (0)
 #elif !defined(NDEBUG)
-SQLITE_PRIVATE   int sqlite3Assert(void);
-# define ALWAYS(X)      ((X)?1:sqlite3Assert())
-# define NEVER(X)       ((X)?sqlite3Assert():0)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
 #else
 # define ALWAYS(X)      (X)
 # define NEVER(X)       (X)
 #endif
 
+/*
+** Return true (non-zero) if the input is a integer that is too large
+** to fit in 32-bits.  This macro is used inside of various testcase()
+** macros to verify that we have tested SQLite for large-file support.
+*/
+#define IS_BIG_INT(X)  (((X)&~(i64)0xffffffff)!=0)
+
 /*
 ** The macro unlikely() is a hint that surrounds a boolean
 ** expression that is usually false.  Macro likely() surrounds
@@ -484,20 +562,6 @@ SQLITE_PRIVATE   int sqlite3Assert(void);
 # define unlikely(X)  !!(X)
 #endif
 
-/*
-** Sometimes we need a small amount of code such as a variable initialization
-** to setup for a later assert() statement.  We do not want this code to
-** appear when assert() is disabled.  The following macro is therefore
-** used to contain that setup code.  The "VVA" acronym stands for
-** "Verification, Validation, and Accreditation".  In other words, the
-** code within VVA_ONLY() will only run during verification processes.
-*/
-#ifndef NDEBUG
-# define VVA_ONLY(X)  X
-#else
-# define VVA_ONLY(X)
-#endif
-
 /************** Include sqlite3.h in the middle of sqliteInt.h ***************/
 /************** Begin file sqlite3.h *****************************************/
 /*
@@ -520,8 +584,8 @@ SQLITE_PRIVATE   int sqlite3Assert(void);
 ** Some of the definitions that are in this file are marked as
 ** "experimental".  Experimental interfaces are normally new
 ** features recently added to SQLite.  We do not anticipate changes
-** to experimental interfaces but reserve to make minor changes if
-** experience from use "in the wild" suggest such changes are prudent.
+** to experimental interfaces but reserve the right to make minor changes
+** if experience from use "in the wild" suggest such changes are prudent.
 **
 ** The official C-language API documentation for SQLite is derived
 ** from comments in this file.  This file is the authoritative source
@@ -531,8 +595,6 @@ SQLITE_PRIVATE   int sqlite3Assert(void);
 ** The makefile makes some minor changes to this file (such as inserting
 ** the version number) and changes its name to "sqlite3.h" as
 ** part of the build process.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _SQLITE3_H_
 #define _SQLITE3_H_
@@ -553,10 +615,15 @@ extern "C" {
 # define SQLITE_EXTERN extern
 #endif
 
+#ifndef SQLITE_API
+# define SQLITE_API
+#endif
+
+
 /*
 ** These no-op macros are used in front of interfaces to mark those
 ** interfaces as either deprecated or experimental.  New applications
-** should not use deprecated intrfaces - they are support for backwards
+** should not use deprecated interfaces - they are support for backwards
 ** compatibility only.  Application writers should be aware that
 ** experimental interfaces are subject to change in point releases.
 **
@@ -580,74 +647,107 @@ extern "C" {
 #endif
 
 /*
-** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100>
+** CAPI3REF: Compile-Time Library Version Numbers
 **
-** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in
-** the sqlite3.h file specify the version of SQLite with which
-** that header file is associated.
+** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
+** evaluates to a string literal that is the SQLite version in the
+** format "X.Y.Z" where X is the major version number (always 3 for
+** SQLite3) and Y is the minor version number and Z is the release number.)^
+** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
+** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
+** numbers used in [SQLITE_VERSION].)^
+** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
+** be larger than the release from which it is derived.  Either Y will
+** be held constant and Z will be incremented or else Y will be incremented
+** and Z will be reset to zero.
 **
-** The "version" of SQLite is a string of the form "X.Y.Z".
-** The phrase "alpha" or "beta" might be appended after the Z.
-** The X value is major version number always 3 in SQLite3.
-** The X value only changes when backwards compatibility is
-** broken and we intend to never break backwards compatibility.
-** The Y value is the minor version number and only changes when
-** there are major feature enhancements that are forwards compatible
-** but not backwards compatible.
-** The Z value is the release number and is incremented with
-** each release but resets back to 0 whenever Y is incremented.
+** Since version 3.6.18, SQLite source code has been stored in the
+** <a href="http://www.fossil-scm.org/">Fossil configuration management
+** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
+** a string which identifies a particular check-in of SQLite
+** within its configuration management system.  ^The SQLITE_SOURCE_ID
+** string contains the date and time of the check-in (UTC) and an SHA1
+** hash of the entire source tree.
 **
-** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()].
-**
-** INVARIANTS:
-**
-** {H10011} The SQLITE_VERSION #define in the sqlite3.h header file shall
-**          evaluate to a string literal that is the SQLite version
-**          with which the header file is associated.
-**
-** {H10014} The SQLITE_VERSION_NUMBER #define shall resolve to an integer
-**          with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z
-**          are the major version, minor version, and release number.
+** See also: [sqlite3_libversion()],
+** [sqlite3_libversion_number()], [sqlite3_sourceid()],
+** [sqlite_version()] and [sqlite_source_id()].
 */
-#define SQLITE_VERSION         "3.6.10"
-#define SQLITE_VERSION_NUMBER  3006010
+#define SQLITE_VERSION        "3.7.14.1"
+#define SQLITE_VERSION_NUMBER 3007014
+#define SQLITE_SOURCE_ID      "2012-10-04 19:37:12 091570e46d04e84b67228e0bdbcd6e1fb60c6bdb"
 
 /*
-** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
-** KEYWORDS: sqlite3_version
+** CAPI3REF: Run-Time Library Version Numbers
+** KEYWORDS: sqlite3_version, sqlite3_sourceid
 **
-** These features provide the same information as the [SQLITE_VERSION]
-** and [SQLITE_VERSION_NUMBER] #defines in the header, but are associated
-** with the library instead of the header file.  Cautious programmers might
-** include a check in their application to verify that
-** sqlite3_libversion_number() always returns the value
-** [SQLITE_VERSION_NUMBER].
+** These interfaces provide the same information as the [SQLITE_VERSION],
+** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
+** but are associated with the library instead of the header file.  ^(Cautious
+** programmers might include assert() statements in their application to
+** verify that values returned by these interfaces match the macros in
+** the header, and thus insure that the application is
+** compiled with matching library and header files.
 **
-** The sqlite3_libversion() function returns the same information as is
-** in the sqlite3_version[] string constant.  The function is provided
-** for use in DLLs since DLL users usually do not have direct access to string
-** constants within the DLL.
+** <blockquote><pre>
+** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
+** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
+** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
+** </pre></blockquote>)^
 **
-** INVARIANTS:
+** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
+** macro.  ^The sqlite3_libversion() function returns a pointer to the
+** to the sqlite3_version[] string constant.  The sqlite3_libversion()
+** function is provided for use in DLLs since DLL users usually do not have
+** direct access to string constants within the DLL.  ^The
+** sqlite3_libversion_number() function returns an integer equal to
+** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns 
+** a pointer to a string constant whose value is the same as the 
+** [SQLITE_SOURCE_ID] C preprocessor macro.
 **
-** {H10021} The [sqlite3_libversion_number()] interface shall return
-**          an integer equal to [SQLITE_VERSION_NUMBER].
-**
-** {H10022} The [sqlite3_version] string constant shall contain
-**          the text of the [SQLITE_VERSION] string.
-**
-** {H10023} The [sqlite3_libversion()] function shall return
-**          a pointer to the [sqlite3_version] string constant.
+** See also: [sqlite_version()] and [sqlite_source_id()].
 */
 SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
 SQLITE_API const char *sqlite3_libversion(void);
+SQLITE_API const char *sqlite3_sourceid(void);
 SQLITE_API int sqlite3_libversion_number(void);
 
 /*
-** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100>
+** CAPI3REF: Run-Time Library Compilation Options Diagnostics
+**
+** ^The sqlite3_compileoption_used() function returns 0 or 1 
+** indicating whether the specified option was defined at 
+** compile time.  ^The SQLITE_ prefix may be omitted from the 
+** option name passed to sqlite3_compileoption_used().  
+**
+** ^The sqlite3_compileoption_get() function allows iterating
+** over the list of options that were defined at compile time by
+** returning the N-th compile time option string.  ^If N is out of range,
+** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_ 
+** prefix is omitted from any strings returned by 
+** sqlite3_compileoption_get().
+**
+** ^Support for the diagnostic functions sqlite3_compileoption_used()
+** and sqlite3_compileoption_get() may be omitted by specifying the 
+** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
+**
+** See also: SQL functions [sqlite_compileoption_used()] and
+** [sqlite_compileoption_get()] and the [compile_options pragma].
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
+SQLITE_API const char *sqlite3_compileoption_get(int N);
+#endif
+
+/*
+** CAPI3REF: Test To See If The Library Is Threadsafe
+**
+** ^The sqlite3_threadsafe() function returns zero if and only if
+** SQLite was compiled with mutexing code omitted due to the
+** [SQLITE_THREADSAFE] compile-time option being set to 0.
 **
 ** SQLite can be compiled with or without mutexes.  When
-** the [SQLITE_THREADSAFE] C preprocessor macro 1 or 2, mutexes
+** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
 ** are enabled and SQLite is threadsafe.  When the
 ** [SQLITE_THREADSAFE] macro is 0, 
 ** the mutexes are omitted.  Without the mutexes, it is not safe
@@ -656,42 +756,37 @@ SQLITE_API int sqlite3_libversion_number(void);
 ** Enabling mutexes incurs a measurable performance penalty.
 ** So if speed is of utmost importance, it makes sense to disable
 ** the mutexes.  But for maximum safety, mutexes should be enabled.
-** The default behavior is for mutexes to be enabled.
+** ^The default behavior is for mutexes to be enabled.
 **
-** This interface can be used by a program to make sure that the
+** This interface can be used by an application to make sure that the
 ** version of SQLite that it is linking against was compiled with
 ** the desired setting of the [SQLITE_THREADSAFE] macro.
 **
 ** This interface only reports on the compile-time mutex setting
 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
-** SQLITE_THREADSAFE=1 then mutexes are enabled by default but
+** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
 ** can be fully or partially disabled using a call to [sqlite3_config()]
 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
-** or [SQLITE_CONFIG_MUTEX].  The return value of this function shows
-** only the default compile-time setting, not any run-time changes
-** to that setting.
+** or [SQLITE_CONFIG_MUTEX].  ^(The return value of the
+** sqlite3_threadsafe() function shows only the compile-time setting of
+** thread safety, not any run-time changes to that setting made by
+** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
+** is unchanged by calls to sqlite3_config().)^
 **
 ** See the [threading mode] documentation for additional information.
-**
-** INVARIANTS:
-**
-** {H10101} The [sqlite3_threadsafe()] function shall return zero if
-**          and only if SQLite was compiled with mutexing code omitted.
-**
-** {H10102} The value returned by the [sqlite3_threadsafe()] function
-**          shall remain the same across calls to [sqlite3_config()].
 */
 SQLITE_API int sqlite3_threadsafe(void);
 
 /*
-** CAPI3REF: Database Connection Handle {H12000} <S40200>
+** CAPI3REF: Database Connection Handle
 ** KEYWORDS: {database connection} {database connections}
 **
 ** Each open SQLite database is represented by a pointer to an instance of
 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
-** is its destructor.  There are many other interfaces (such as
+** and [sqlite3_close_v2()] are its destructors.  There are many other
+** interfaces (such as
 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
 ** sqlite3 object.
@@ -699,7 +794,7 @@ SQLITE_API int sqlite3_threadsafe(void);
 typedef struct sqlite3 sqlite3;
 
 /*
-** CAPI3REF: 64-Bit Integer Types {H10200} <S10110>
+** CAPI3REF: 64-Bit Integer Types
 ** KEYWORDS: sqlite_int64 sqlite_uint64
 **
 ** Because there is no cross-platform way to specify 64-bit integer types
@@ -709,13 +804,10 @@ typedef struct sqlite3 sqlite3;
 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
 ** compatibility only.
 **
-** INVARIANTS:
-**
-** {H10201} The [sqlite_int64] and [sqlite3_int64] type shall specify
-**          a 64-bit signed integer.
-**
-** {H10202} The [sqlite_uint64] and [sqlite3_uint64] type shall specify
-**          a 64-bit unsigned integer.
+** ^The sqlite3_int64 and sqlite_int64 types can store integer values
+** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
+** sqlite3_uint64 and sqlite_uint64 types can store integer values 
+** between 0 and +18446744073709551615 inclusive.
 */
 #ifdef SQLITE_INT64_TYPE
   typedef SQLITE_INT64_TYPE sqlite_int64;
@@ -739,57 +831,48 @@ typedef sqlite_uint64 sqlite3_uint64;
 #endif
 
 /*
-** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200>
+** CAPI3REF: Closing A Database Connection
 **
-** This routine is the destructor for the [sqlite3] object.
+** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
+** for the [sqlite3] object.
+** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if
+** the [sqlite3] object is successfully destroyed and all associated
+** resources are deallocated.
 **
-** Applications should [sqlite3_finalize | finalize] all [prepared statements]
-** and [sqlite3_blob_close | close] all [BLOB handles] associated with
-** the [sqlite3] object prior to attempting to close the object.
-** The [sqlite3_next_stmt()] interface can be used to locate all
-** [prepared statements] associated with a [database connection] if desired.
-** Typical code might look like this:
+** ^If the database connection is associated with unfinalized prepared
+** statements or unfinished sqlite3_backup objects then sqlite3_close()
+** will leave the database connection open and return [SQLITE_BUSY].
+** ^If sqlite3_close_v2() is called with unfinalized prepared statements
+** and unfinished sqlite3_backups, then the database connection becomes
+** an unusable "zombie" which will automatically be deallocated when the
+** last prepared statement is finalized or the last sqlite3_backup is
+** finished.  The sqlite3_close_v2() interface is intended for use with
+** host languages that are garbage collected, and where the order in which
+** destructors are called is arbitrary.
 **
-** <blockquote><pre>
-** sqlite3_stmt *pStmt;
-** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){
-** &nbsp;   sqlite3_finalize(pStmt);
-** }
-** </pre></blockquote>
+** Applications should [sqlite3_finalize | finalize] all [prepared statements],
+** [sqlite3_blob_close | close] all [BLOB handles], and 
+** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
+** with the [sqlite3] object prior to attempting to close the object.  ^If
+** sqlite3_close() is called on a [database connection] that still has
+** outstanding [prepared statements], [BLOB handles], and/or
+** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation
+** of resources is deferred until all [prepared statements], [BLOB handles],
+** and [sqlite3_backup] objects are also destroyed.
 **
-** If [sqlite3_close()] is invoked while a transaction is open,
+** ^If an [sqlite3] object is destroyed while a transaction is open,
 ** the transaction is automatically rolled back.
 **
-** INVARIANTS:
-**
-** {H12011} A successful call to [sqlite3_close(C)] shall destroy the
-**          [database connection] object C.
-**
-** {H12012} A successful call to [sqlite3_close(C)] shall return SQLITE_OK.
-**
-** {H12013} A successful call to [sqlite3_close(C)] shall release all
-**          memory and system resources associated with [database connection]
-**          C.
-**
-** {H12014} A call to [sqlite3_close(C)] on a [database connection] C that
-**          has one or more open [prepared statements] shall fail with
-**          an [SQLITE_BUSY] error code.
-**
-** {H12015} A call to [sqlite3_close(C)] where C is a NULL pointer shall
-**          be a harmless no-op returning SQLITE_OK.
-**
-** {H12019} When [sqlite3_close(C)] is invoked on a [database connection] C
-**          that has a pending transaction, the transaction shall be
-**          rolled back.
-**
-** ASSUMPTIONS:
-**
-** {A12016} The C parameter to [sqlite3_close(C)] must be either a NULL
-**          pointer or an [sqlite3] object pointer obtained
-**          from [sqlite3_open()], [sqlite3_open16()], or
-**          [sqlite3_open_v2()], and not previously closed.
+** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
+** must be either a NULL
+** pointer or an [sqlite3] object pointer obtained
+** from [sqlite3_open()], [sqlite3_open16()], or
+** [sqlite3_open_v2()], and not previously closed.
+** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
+** argument is a harmless no-op.
 */
-SQLITE_API int sqlite3_close(sqlite3 *);
+SQLITE_API int sqlite3_close(sqlite3*);
+SQLITE_API int sqlite3_close_v2(sqlite3*);
 
 /*
 ** The type for a callback function.
@@ -799,112 +882,65 @@ SQLITE_API int sqlite3_close(sqlite3 *);
 typedef int (*sqlite3_callback)(void*,int,char**, char**);
 
 /*
-** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000>
+** CAPI3REF: One-Step Query Execution Interface
 **
-** The sqlite3_exec() interface is a convenient way of running one or more
-** SQL statements without having to write a lot of C code.  The UTF-8 encoded
-** SQL statements are passed in as the second parameter to sqlite3_exec().
-** The statements are evaluated one by one until either an error or
-** an interrupt is encountered, or until they are all done.  The 3rd parameter
-** is an optional callback that is invoked once for each row of any query
-** results produced by the SQL statements.  The 5th parameter tells where
-** to write any error messages.
+** The sqlite3_exec() interface is a convenience wrapper around
+** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
+** that allows an application to run multiple statements of SQL
+** without having to use a lot of C code. 
 **
-** The error message passed back through the 5th parameter is held
-** in memory obtained from [sqlite3_malloc()].  To avoid a memory leak,
-** the calling application should call [sqlite3_free()] on any error
-** message returned through the 5th parameter when it has finished using
-** the error message.
+** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
+** semicolon-separate SQL statements passed into its 2nd argument,
+** in the context of the [database connection] passed in as its 1st
+** argument.  ^If the callback function of the 3rd argument to
+** sqlite3_exec() is not NULL, then it is invoked for each result row
+** coming out of the evaluated SQL statements.  ^The 4th argument to
+** sqlite3_exec() is relayed through to the 1st argument of each
+** callback invocation.  ^If the callback pointer to sqlite3_exec()
+** is NULL, then no callback is ever invoked and result rows are
+** ignored.
 **
-** If the SQL statement in the 2nd parameter is NULL or an empty string
-** or a string containing only whitespace and comments, then no SQL
-** statements are evaluated and the database is not changed.
+** ^If an error occurs while evaluating the SQL statements passed into
+** sqlite3_exec(), then execution of the current statement stops and
+** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
+** is not NULL then any error message is written into memory obtained
+** from [sqlite3_malloc()] and passed back through the 5th parameter.
+** To avoid memory leaks, the application should invoke [sqlite3_free()]
+** on error message strings returned through the 5th parameter of
+** of sqlite3_exec() after the error message string is no longer needed.
+** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
+** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
+** NULL before returning.
 **
-** The sqlite3_exec() interface is implemented in terms of
-** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
-** The sqlite3_exec() routine does nothing to the database that cannot be done
-** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
+** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
+** routine returns SQLITE_ABORT without invoking the callback again and
+** without running any subsequent SQL statements.
 **
-** INVARIANTS:
+** ^The 2nd argument to the sqlite3_exec() callback function is the
+** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
+** callback is an array of pointers to strings obtained as if from
+** [sqlite3_column_text()], one for each column.  ^If an element of a
+** result row is NULL then the corresponding string pointer for the
+** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
+** sqlite3_exec() callback is an array of pointers to strings where each
+** entry represents the name of corresponding result column as obtained
+** from [sqlite3_column_name()].
 **
-** {H12101} A successful invocation of [sqlite3_exec(D,S,C,A,E)]
-**          shall sequentially evaluate all of the UTF-8 encoded,
-**          semicolon-separated SQL statements in the zero-terminated
-**          string S within the context of the [database connection] D.
+** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
+** to an empty string, or a pointer that contains only whitespace and/or 
+** SQL comments, then no SQL statements are evaluated and the database
+** is not changed.
 **
-** {H12102} If the S parameter to [sqlite3_exec(D,S,C,A,E)] is NULL then
-**          the actions of the interface shall be the same as if the
-**          S parameter were an empty string.
+** Restrictions:
 **
-** {H12104} The return value of [sqlite3_exec()] shall be [SQLITE_OK] if all
-**          SQL statements run successfully and to completion.
-**
-** {H12105} The return value of [sqlite3_exec()] shall be an appropriate
-**          non-zero [error code] if any SQL statement fails.
-**
-** {H12107} If one or more of the SQL statements handed to [sqlite3_exec()]
-**          return results and the 3rd parameter is not NULL, then
-**          the callback function specified by the 3rd parameter shall be
-**          invoked once for each row of result.
-**
-** {H12110} If the callback returns a non-zero value then [sqlite3_exec()]
-**          shall abort the SQL statement it is currently evaluating,
-**          skip all subsequent SQL statements, and return [SQLITE_ABORT].
-**
-** {H12113} The [sqlite3_exec()] routine shall pass its 4th parameter through
-**          as the 1st parameter of the callback.
-**
-** {H12116} The [sqlite3_exec()] routine shall set the 2nd parameter of its
-**          callback to be the number of columns in the current row of
-**          result.
-**
-** {H12119} The [sqlite3_exec()] routine shall set the 3rd parameter of its
-**          callback to be an array of pointers to strings holding the
-**          values for each column in the current result set row as
-**          obtained from [sqlite3_column_text()].
-**
-** {H12122} The [sqlite3_exec()] routine shall set the 4th parameter of its
-**          callback to be an array of pointers to strings holding the
-**          names of result columns as obtained from [sqlite3_column_name()].
-**
-** {H12125} If the 3rd parameter to [sqlite3_exec()] is NULL then
-**          [sqlite3_exec()] shall silently discard query results.
-**
-** {H12131} If an error occurs while parsing or evaluating any of the SQL
-**          statements in the S parameter of [sqlite3_exec(D,S,C,A,E)] and if
-**          the E parameter is not NULL, then [sqlite3_exec()] shall store
-**          in *E an appropriate error message written into memory obtained
-**          from [sqlite3_malloc()].
-**
-** {H12134} The [sqlite3_exec(D,S,C,A,E)] routine shall set the value of
-**          *E to NULL if E is not NULL and there are no errors.
-**
-** {H12137} The [sqlite3_exec(D,S,C,A,E)] function shall set the [error code]
-**          and message accessible via [sqlite3_errcode()], 
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], and [sqlite3_errmsg16()].
-**
-** {H12138} If the S parameter to [sqlite3_exec(D,S,C,A,E)] is NULL or an
-**          empty string or contains nothing other than whitespace, comments,
-**          and/or semicolons, then results of [sqlite3_errcode()],
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], and [sqlite3_errmsg16()]
-**          shall reset to indicate no errors.
-**
-** ASSUMPTIONS:
-**
-** {A12141} The first parameter to [sqlite3_exec()] must be an valid and open
-**          [database connection].
-**
-** {A12142} The database connection must not be closed while
-**          [sqlite3_exec()] is running.
-**
-** {A12143} The calling function should use [sqlite3_free()] to free
-**          the memory that *errmsg is left pointing at once the error
-**          message is no longer needed.
-**
-** {A12145} The SQL statement text in the 2nd parameter to [sqlite3_exec()]
-**          must remain unchanged while [sqlite3_exec()] is running.
+** <ul>
+** <li> The application must insure that the 1st parameter to sqlite3_exec()
+**      is a valid and open [database connection].
+** <li> The application must not close [database connection] specified by
+**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not modify the SQL statement text passed into
+**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
+** </ul>
 */
 SQLITE_API int sqlite3_exec(
   sqlite3*,                                  /* An open database */
@@ -915,16 +951,17 @@ SQLITE_API int sqlite3_exec(
 );
 
 /*
-** CAPI3REF: Result Codes {H10210} <S10700>
+** CAPI3REF: Result Codes
 ** KEYWORDS: SQLITE_OK {error code} {error codes}
 ** KEYWORDS: {result code} {result codes}
 **
 ** Many SQLite functions return an integer result code from the set shown
-** here in order to indicates success or failure.
+** here in order to indicate success or failure.
 **
 ** New error codes may be added in future versions of SQLite.
 **
-** See also: [SQLITE_IOERR_READ | extended result codes]
+** See also: [SQLITE_IOERR_READ | extended result codes],
+** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
 */
 #define SQLITE_OK           0   /* Successful result */
 /* beginning-of-error-codes */
@@ -939,10 +976,10 @@ SQLITE_API int sqlite3_exec(
 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
-#define SQLITE_NOTFOUND    12   /* NOT USED. Table or record not found */
+#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
 #define SQLITE_FULL        13   /* Insertion failed because database is full */
 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
-#define SQLITE_PROTOCOL    15   /* NOT USED. Database lock protocol error */
+#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
 #define SQLITE_EMPTY       16   /* Database is empty */
 #define SQLITE_SCHEMA      17   /* The database schema changed */
 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
@@ -959,7 +996,7 @@ SQLITE_API int sqlite3_exec(
 /* end-of-error-codes */
 
 /*
-** CAPI3REF: Extended Result Codes {H10220} <S10700>
+** CAPI3REF: Extended Result Codes
 ** KEYWORDS: {extended error code} {extended error codes}
 ** KEYWORDS: {extended result code} {extended result codes}
 **
@@ -980,19 +1017,6 @@ SQLITE_API int sqlite3_exec(
 **
 ** The SQLITE_OK result code will never be extended.  It will always
 ** be exactly zero.
-**
-** INVARIANTS:
-**
-** {H10223} The symbolic name for an extended result code shall contains
-**          a related primary result code as a prefix.
-**
-** {H10224} Primary result code names shall contain a single "_" character.
-**
-** {H10225} Extended result code names shall contain two or more "_" characters.
-**
-** {H10226} The numeric value of an extended result code shall contain the
-**          numeric value of its corresponding primary result code in
-**          its least significant 8 bits.
 */
 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
@@ -1011,35 +1035,55 @@ SQLITE_API int sqlite3_exec(
 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
+#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
+#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
+#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
+#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
+#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
+#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
+#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
+#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
+#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
+#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
+#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
+#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
+#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
 
 /*
-** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700>
+** CAPI3REF: Flags For File Open Operations
 **
 ** These bit values are intended for use in the
 ** 3rd parameter to the [sqlite3_open_v2()] interface and
-** in the 4th parameter to the xOpen method of the
-** [sqlite3_vfs] object.
+** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
 */
-#define SQLITE_OPEN_READONLY         0x00000001
-#define SQLITE_OPEN_READWRITE        0x00000002
-#define SQLITE_OPEN_CREATE           0x00000004
-#define SQLITE_OPEN_DELETEONCLOSE    0x00000008
-#define SQLITE_OPEN_EXCLUSIVE        0x00000010
-#define SQLITE_OPEN_MAIN_DB          0x00000100
-#define SQLITE_OPEN_TEMP_DB          0x00000200
-#define SQLITE_OPEN_TRANSIENT_DB     0x00000400
-#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800
-#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000
-#define SQLITE_OPEN_SUBJOURNAL       0x00002000
-#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000
-#define SQLITE_OPEN_NOMUTEX          0x00008000
-#define SQLITE_OPEN_FULLMUTEX        0x00010000
+#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
+#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
+#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
+#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
+#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
+#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
+#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
+#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
+#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
+#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
+#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
+
+/* Reserved:                         0x00F00000 */
 
 /*
-** CAPI3REF: Device Characteristics {H10240} <H11120>
+** CAPI3REF: Device Characteristics
 **
-** The xDeviceCapabilities method of the [sqlite3_io_methods]
-** object returns an integer which is a vector of the these
+** The xDeviceCharacteristics method of the [sqlite3_io_methods]
+** object returns an integer which is a vector of these
 ** bit values expressing I/O characteristics of the mass storage
 ** device that holds the file that the [sqlite3_io_methods]
 ** refers to.
@@ -1053,22 +1097,28 @@ SQLITE_API int sqlite3_exec(
 ** first then the size of the file is extended, never the other
 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
 ** information is written to disk in the same order as calls
-** to xWrite().
+** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
+** after reboot following a crash or power loss, the only bytes in a
+** file that were written at the application level might have changed
+** and that adjacent bytes, even bytes within the same sector are
+** guaranteed to be unchanged.
 */
-#define SQLITE_IOCAP_ATOMIC          0x00000001
-#define SQLITE_IOCAP_ATOMIC512       0x00000002
-#define SQLITE_IOCAP_ATOMIC1K        0x00000004
-#define SQLITE_IOCAP_ATOMIC2K        0x00000008
-#define SQLITE_IOCAP_ATOMIC4K        0x00000010
-#define SQLITE_IOCAP_ATOMIC8K        0x00000020
-#define SQLITE_IOCAP_ATOMIC16K       0x00000040
-#define SQLITE_IOCAP_ATOMIC32K       0x00000080
-#define SQLITE_IOCAP_ATOMIC64K       0x00000100
-#define SQLITE_IOCAP_SAFE_APPEND     0x00000200
-#define SQLITE_IOCAP_SEQUENTIAL      0x00000400
+#define SQLITE_IOCAP_ATOMIC                 0x00000001
+#define SQLITE_IOCAP_ATOMIC512              0x00000002
+#define SQLITE_IOCAP_ATOMIC1K               0x00000004
+#define SQLITE_IOCAP_ATOMIC2K               0x00000008
+#define SQLITE_IOCAP_ATOMIC4K               0x00000010
+#define SQLITE_IOCAP_ATOMIC8K               0x00000020
+#define SQLITE_IOCAP_ATOMIC16K              0x00000040
+#define SQLITE_IOCAP_ATOMIC32K              0x00000080
+#define SQLITE_IOCAP_ATOMIC64K              0x00000100
+#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
+#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
+#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
+#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
 
 /*
-** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310>
+** CAPI3REF: File Locking Levels
 **
 ** SQLite uses one of these integer values as the second
 ** argument to calls it makes to the xLock() and xUnlock() methods
@@ -1081,7 +1131,7 @@ SQLITE_API int sqlite3_exec(
 #define SQLITE_LOCK_EXCLUSIVE     4
 
 /*
-** CAPI3REF: Synchronization Type Flags {H10260} <H11120>
+** CAPI3REF: Synchronization Type Flags
 **
 ** When SQLite invokes the xSync() method of an
 ** [sqlite3_io_methods] object it uses a combination of
@@ -1089,19 +1139,33 @@ SQLITE_API int sqlite3_exec(
 **
 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
 ** sync operation only needs to flush data to mass storage.  Inode
-** information need not be flushed. The SQLITE_SYNC_NORMAL flag means
-** to use normal fsync() semantics. The SQLITE_SYNC_FULL flag means
+** information need not be flushed. If the lower four bits of the flag
+** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
+** If the lower four bits equal SQLITE_SYNC_FULL, that means
 ** to use Mac OS X style fullsync instead of fsync().
+**
+** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
+** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
+** settings.  The [synchronous pragma] determines when calls to the
+** xSync VFS method occur and applies uniformly across all platforms.
+** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
+** energetic or rigorous or forceful the sync operations are and
+** only make a difference on Mac OSX for the default SQLite code.
+** (Third-party VFS implementations might also make the distinction
+** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
+** operating systems natively supported by SQLite, only Mac OSX
+** cares about the difference.)
 */
 #define SQLITE_SYNC_NORMAL        0x00002
 #define SQLITE_SYNC_FULL          0x00003
 #define SQLITE_SYNC_DATAONLY      0x00010
 
 /*
-** CAPI3REF: OS Interface Open File Handle {H11110} <S20110>
+** CAPI3REF: OS Interface Open File Handle
 **
-** An [sqlite3_file] object represents an open file in the OS
-** interface layer.  Individual OS interface implementations will
+** An [sqlite3_file] object represents an open file in the 
+** [sqlite3_vfs | OS interface layer].  Individual OS interface
+** implementations will
 ** want to subclass this object by appending additional fields
 ** for their own use.  The pMethods entry is a pointer to an
 ** [sqlite3_io_methods] object that defines methods for performing
@@ -1113,14 +1177,21 @@ struct sqlite3_file {
 };
 
 /*
-** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110>
+** CAPI3REF: OS Interface File Virtual Methods Object
 **
-** Every file opened by the [sqlite3_vfs] xOpen method populates an
+** Every file opened by the [sqlite3_vfs.xOpen] method populates an
 ** [sqlite3_file] object (or, more commonly, a subclass of the
 ** [sqlite3_file] object) with a pointer to an instance of this object.
 ** This object defines the methods used to perform various operations
 ** against the open file represented by the [sqlite3_file] object.
 **
+** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 
+** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
+** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
+** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
+** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
+** to NULL.
+**
 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
@@ -1153,7 +1224,9 @@ struct sqlite3_file {
 ** core reserves all opcodes less than 100 for its own use.
 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
 ** Applications that define a custom xFileControl method should use opcodes
-** greater than 100 to avoid conflicts.
+** greater than 100 to avoid conflicts.  VFS implementations should
+** return [SQLITE_NOTFOUND] for file control opcodes that they do not
+** recognize.
 **
 ** The xSectorSize() method returns the sector size of the
 ** device that underlies the file.  The sector size is the
@@ -1208,11 +1281,17 @@ struct sqlite3_io_methods {
   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
   int (*xSectorSize)(sqlite3_file*);
   int (*xDeviceCharacteristics)(sqlite3_file*);
+  /* Methods above are valid for version 1 */
+  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
+  void (*xShmBarrier)(sqlite3_file*);
+  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
+  /* Methods above are valid for version 2 */
   /* Additional methods may be added in future releases */
 };
 
 /*
-** CAPI3REF: Standard File Control Opcodes {H11310} <S30800>
+** CAPI3REF: Standard File Control Opcodes
 **
 ** These integer constants are opcodes for the xFileControl method
 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
@@ -1225,14 +1304,142 @@ struct sqlite3_io_methods {
 ** into an integer that the pArg argument points to. This capability
 ** is used during testing and only needs to be supported when SQLITE_TEST
 ** is defined.
+** <ul>
+** <li>[[SQLITE_FCNTL_SIZE_HINT]]
+** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
+** layer a hint of how large the database file will grow to be during the
+** current transaction.  This hint is not guaranteed to be accurate but it
+** is often close.  The underlying VFS might choose to preallocate database
+** file space based on this hint in order to help writes to the database
+** file run faster.
+**
+** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
+** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
+** extends and truncates the database file in chunks of a size specified
+** by the user. The fourth argument to [sqlite3_file_control()] should 
+** point to an integer (type int) containing the new chunk-size to use
+** for the nominated database. Allocating database file space in large
+** chunks (say 1MB at a time), may reduce file-system fragmentation and
+** improve performance on some systems.
+**
+** <li>[[SQLITE_FCNTL_FILE_POINTER]]
+** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with a particular database
+** connection.  See the [sqlite3_file_control()] documentation for
+** additional information.
+**
+** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
+** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
+** SQLite and sent to all VFSes in place of a call to the xSync method
+** when the database connection has [PRAGMA synchronous] set to OFF.)^
+** Some specialized VFSes need this signal in order to operate correctly
+** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 
+** VFSes do not need this signal and should silently ignore this opcode.
+** Applications should not call [sqlite3_file_control()] with this
+** opcode as doing so may disrupt the operation of the specialized VFSes
+** that do require it.  
+**
+** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
+** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
+** retry counts and intervals for certain disk I/O operations for the
+** windows [VFS] in order to provide robustness in the presence of
+** anti-virus programs.  By default, the windows VFS will retry file read,
+** file write, and file delete operations up to 10 times, with a delay
+** of 25 milliseconds before the first retry and with the delay increasing
+** by an additional 25 milliseconds with each subsequent retry.  This
+** opcode allows these two values (10 retries and 25 milliseconds of delay)
+** to be adjusted.  The values are changed for all database connections
+** within the same process.  The argument is a pointer to an array of two
+** integers where the first integer i the new retry count and the second
+** integer is the delay.  If either integer is negative, then the setting
+** is not changed but instead the prior value of that setting is written
+** into the array entry, allowing the current retry settings to be
+** interrogated.  The zDbName parameter is ignored.
+**
+** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
+** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
+** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
+** write ahead log and shared memory files used for transaction control
+** are automatically deleted when the latest connection to the database
+** closes.  Setting persistent WAL mode causes those files to persist after
+** close.  Persisting the files is useful when other processes that do not
+** have write permission on the directory containing the database file want
+** to read the database file, as the WAL and shared memory files must exist
+** in order for the database to be readable.  The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
+** WAL mode.  If the integer is -1, then it is overwritten with the current
+** WAL persistence setting.
+**
+** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
+** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
+** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
+** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
+** xDeviceCharacteristics methods. The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
+** mode.  If the integer is -1, then it is overwritten with the current
+** zero-damage mode setting.
+**
+** <li>[[SQLITE_FCNTL_OVERWRITE]]
+** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
+** a write transaction to indicate that, unless it is rolled back for some
+** reason, the entire database file will be overwritten by the current 
+** transaction. This is used by VACUUM operations.
+**
+** <li>[[SQLITE_FCNTL_VFSNAME]]
+** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
+** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
+** final bottom-level VFS are written into memory obtained from 
+** [sqlite3_malloc()] and the result is stored in the char* variable
+** that the fourth parameter of [sqlite3_file_control()] points to.
+** The caller is responsible for freeing the memory when done.  As with
+** all file-control actions, there is no guarantee that this will actually
+** do anything.  Callers should initialize the char* variable to a NULL
+** pointer in case this file-control is not implemented.  This file-control
+** is intended for diagnostic use only.
+**
+** <li>[[SQLITE_FCNTL_PRAGMA]]
+** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 
+** file control is sent to the open [sqlite3_file] object corresponding
+** to the database file to which the pragma statement refers. ^The argument
+** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
+** pointers to strings (char**) in which the second element of the array
+** is the name of the pragma and the third element is the argument to the
+** pragma or NULL if the pragma has no argument.  ^The handler for an
+** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
+** of the char** argument point to a string obtained from [sqlite3_mprintf()]
+** or the equivalent and that string will become the result of the pragma or
+** the error message if the pragma fails. ^If the
+** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 
+** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
+** file control returns [SQLITE_OK], then the parser assumes that the
+** VFS has handled the PRAGMA itself and the parser generates a no-op
+** prepared statement.  ^If the [SQLITE_FCNTL_PRAGMA] file control returns
+** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
+** that the VFS encountered an error while handling the [PRAGMA] and the
+** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
+** file control occurs at the beginning of pragma statement analysis and so
+** it is able to override built-in [PRAGMA] statements.
+** </ul>
 */
-#define SQLITE_FCNTL_LOCKSTATE        1
-#define SQLITE_GET_LOCKPROXYFILE      2
-#define SQLITE_SET_LOCKPROXYFILE      3
-#define SQLITE_LAST_ERRNO             4
+#define SQLITE_FCNTL_LOCKSTATE               1
+#define SQLITE_GET_LOCKPROXYFILE             2
+#define SQLITE_SET_LOCKPROXYFILE             3
+#define SQLITE_LAST_ERRNO                    4
+#define SQLITE_FCNTL_SIZE_HINT               5
+#define SQLITE_FCNTL_CHUNK_SIZE              6
+#define SQLITE_FCNTL_FILE_POINTER            7
+#define SQLITE_FCNTL_SYNC_OMITTED            8
+#define SQLITE_FCNTL_WIN32_AV_RETRY          9
+#define SQLITE_FCNTL_PERSIST_WAL            10
+#define SQLITE_FCNTL_OVERWRITE              11
+#define SQLITE_FCNTL_VFSNAME                12
+#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
+#define SQLITE_FCNTL_PRAGMA                 14
 
 /*
-** CAPI3REF: Mutex Handle {H17110} <S20130>
+** CAPI3REF: Mutex Handle
 **
 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
 ** abstract type for a mutex object.  The SQLite core never looks
@@ -1244,11 +1451,12 @@ struct sqlite3_io_methods {
 typedef struct sqlite3_mutex sqlite3_mutex;
 
 /*
-** CAPI3REF: OS Interface Object {H11140} <S20100>
+** CAPI3REF: OS Interface Object
 **
 ** An instance of the sqlite3_vfs object defines the interface between
 ** the SQLite core and the underlying operating system.  The "vfs"
-** in the name of the object stands for "virtual file system".
+** in the name of the object stands for "virtual file system".  See
+** the [VFS | VFS documentation] for further information.
 **
 ** The value of the iVersion field is initially 1 but may be larger in
 ** future versions of SQLite.  Additional fields may be appended to this
@@ -1277,15 +1485,20 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** The zName field holds the name of the VFS module.  The name must
 ** be unique across all VFS modules.
 **
-** SQLite will guarantee that the zFilename parameter to xOpen
+** [[sqlite3_vfs.xOpen]]
+** ^SQLite guarantees that the zFilename parameter to xOpen
 ** is either a NULL pointer or string obtained
-** from xFullPathname().  SQLite further guarantees that
+** from xFullPathname() with an optional suffix added.
+** ^If a suffix is added to the zFilename parameter, it will
+** consist of a single "-" character followed by no more than
+** 11 alphanumeric and/or "-" characters.
+** ^SQLite further guarantees that
 ** the string will be valid and unchanged until xClose() is
-** called. Because of the previous sentense,
+** called. Because of the previous sentence,
 ** the [sqlite3_file] can safely store a pointer to the
 ** filename if it needs to remember the filename for some reason.
-** If the zFilename parameter is xOpen is a NULL pointer then xOpen
-** must invite its own temporary name for the file.  Whenever the 
+** If the zFilename parameter to xOpen is a NULL pointer then xOpen
+** must invent its own temporary name for the file.  ^Whenever the 
 ** xFilename parameter is NULL it will also be the case that the
 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
 **
@@ -1296,7 +1509,7 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** If xOpen() opens a file read-only then it sets *pOutFlags to
 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
 **
-** SQLite will also add one of the following flags to the xOpen()
+** ^(SQLite will also add one of the following flags to the xOpen()
 ** call, depending on the object being opened:
 **
 ** <ul>
@@ -1307,7 +1520,8 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
-** </ul>
+** <li>  [SQLITE_OPEN_WAL]
+** </ul>)^
 **
 ** The file I/O implementation can use the object type flags to
 ** change the way it deals with files.  For example, an application
@@ -1326,45 +1540,77 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** </ul>
 **
 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
-** deleted when it is closed.  The [SQLITE_OPEN_DELETEONCLOSE]
-** will be set for TEMP  databases, journals and for subjournals.
+** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
+** will be set for TEMP databases and their journals, transient
+** databases, and subjournals.
 **
-** The [SQLITE_OPEN_EXCLUSIVE] flag means the file should be opened
-** for exclusive access.  This flag is set for all files except
-** for the main database file.
+** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
+** with the [SQLITE_OPEN_CREATE] flag, which are both directly
+** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
+** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 
+** SQLITE_OPEN_CREATE, is used to indicate that file should always
+** be created, and that it is an error if it already exists.
+** It is <i>not</i> used to indicate the file should be opened 
+** for exclusive access.
 **
-** At least szOsFile bytes of memory are allocated by SQLite
+** ^At least szOsFile bytes of memory are allocated by SQLite
 ** to hold the  [sqlite3_file] structure passed as the third
 ** argument to xOpen.  The xOpen method does not have to
-** allocate the structure; it should just fill it in.
+** allocate the structure; it should just fill it in.  Note that
+** the xOpen method must set the sqlite3_file.pMethods to either
+** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
+** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
+** element will be valid after xOpen returns regardless of the success
+** or failure of the xOpen call.
 **
-** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
+** [[sqlite3_vfs.xAccess]]
+** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
 ** to test whether a file is at least readable.   The file can be a
 ** directory.
 **
-** SQLite will always allocate at least mxPathname+1 bytes for the
+** ^SQLite will always allocate at least mxPathname+1 bytes for the
 ** output buffer xFullPathname.  The exact size of the output buffer
 ** is also passed as a parameter to both  methods. If the output buffer
 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
 ** handled as a fatal error by SQLite, vfs implementations should endeavor
 ** to prevent this by setting mxPathname to a sufficiently large value.
 **
-** The xRandomness(), xSleep(), and xCurrentTime() interfaces
-** are not strictly a part of the filesystem, but they are
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
 ** included in the VFS structure for completeness.
 ** The xRandomness() function attempts to return nBytes bytes
 ** of good-quality randomness into zOut.  The return value is
 ** the actual number of bytes of randomness obtained.
 ** The xSleep() method causes the calling thread to sleep for at
-** least the number of microseconds given.  The xCurrentTime()
-** method returns a Julian Day Number for the current date and time.
+** least the number of microseconds given.  ^The xCurrentTime()
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multiplied by 86400000 (the number of milliseconds in 
+** a 24-hour day).  
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or 
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
 **
+** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
+** are not used by the SQLite core.  These optional interfaces are provided
+** by some VFSes to facilitate testing of the VFS code. By overriding 
+** system calls with functions under its control, a test program can
+** simulate faults and error conditions that would otherwise be difficult
+** or impossible to induce.  The set of system calls that can be overridden
+** varies from one VFS to another, and from one version of the same VFS to the
+** next.  Applications that use these interfaces must be prepared for any
+** or all of these interfaces to be NULL or for their behavior to change
+** from one release to the next.  Applications must not attempt to access
+** any of these methods if the iVersion of the VFS is less than 3.
 */
 typedef struct sqlite3_vfs sqlite3_vfs;
+typedef void (*sqlite3_syscall_ptr)(void);
 struct sqlite3_vfs {
-  int iVersion;            /* Structure version number */
+  int iVersion;            /* Structure version number (currently 3) */
   int szOsFile;            /* Size of subclassed sqlite3_file */
   int mxPathname;          /* Maximum file pathname length */
   sqlite3_vfs *pNext;      /* Next registered VFS */
@@ -1383,56 +1629,130 @@ struct sqlite3_vfs {
   int (*xSleep)(sqlite3_vfs*, int microseconds);
   int (*xCurrentTime)(sqlite3_vfs*, double*);
   int (*xGetLastError)(sqlite3_vfs*, int, char *);
-  /* New fields may be appended in figure versions.  The iVersion
-  ** value will increment whenever this happens. */
+  /*
+  ** The methods above are in version 1 of the sqlite_vfs object
+  ** definition.  Those that follow are added in version 2 or later
+  */
+  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
+  /*
+  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
+  ** Those below are for version 3 and greater.
+  */
+  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
+  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
+  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
+  /*
+  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
+  ** New fields may be appended in figure versions.  The iVersion
+  ** value will increment whenever this happens. 
+  */
 };
 
 /*
-** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140>
+** CAPI3REF: Flags for the xAccess VFS method
 **
 ** These integer constants can be used as the third parameter to
-** the xAccess method of an [sqlite3_vfs] object. {END}  They determine
+** the xAccess method of an [sqlite3_vfs] object.  They determine
 ** what kind of permissions the xAccess method is looking for.
 ** With SQLITE_ACCESS_EXISTS, the xAccess method
 ** simply checks whether the file exists.
 ** With SQLITE_ACCESS_READWRITE, the xAccess method
-** checks whether the file is both readable and writable.
+** checks whether the named directory is both readable and writable
+** (in other words, if files can be added, removed, and renamed within
+** the directory).
+** The SQLITE_ACCESS_READWRITE constant is currently used only by the
+** [temp_store_directory pragma], though this could change in a future
+** release of SQLite.
 ** With SQLITE_ACCESS_READ, the xAccess method
-** checks whether the file is readable.
+** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
+** currently unused, though it might be used in a future release of
+** SQLite.
 */
 #define SQLITE_ACCESS_EXISTS    0
-#define SQLITE_ACCESS_READWRITE 1
-#define SQLITE_ACCESS_READ      2
+#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
+#define SQLITE_ACCESS_READ      2   /* Unused */
 
 /*
-** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100>
+** CAPI3REF: Flags for the xShmLock VFS method
 **
-** The sqlite3_initialize() routine initializes the
-** SQLite library.  The sqlite3_shutdown() routine
+** These integer constants define the various locking operations
+** allowed by the xShmLock method of [sqlite3_io_methods].  The
+** following are the only legal combinations of flags to the
+** xShmLock method:
+**
+** <ul>
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
+** </ul>
+**
+** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
+** was given no the corresponding lock.  
+**
+** The xShmLock method can transition between unlocked and SHARED or
+** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
+** and EXCLUSIVE.
+*/
+#define SQLITE_SHM_UNLOCK       1
+#define SQLITE_SHM_LOCK         2
+#define SQLITE_SHM_SHARED       4
+#define SQLITE_SHM_EXCLUSIVE    8
+
+/*
+** CAPI3REF: Maximum xShmLock index
+**
+** The xShmLock method on [sqlite3_io_methods] may use values
+** between 0 and this upper bound as its "offset" argument.
+** The SQLite core will never attempt to acquire or release a
+** lock outside of this range
+*/
+#define SQLITE_SHM_NLOCK        8
+
+
+/*
+** CAPI3REF: Initialize The SQLite Library
+**
+** ^The sqlite3_initialize() routine initializes the
+** SQLite library.  ^The sqlite3_shutdown() routine
 ** deallocates any resources that were allocated by sqlite3_initialize().
+** These routines are designed to aid in process initialization and
+** shutdown on embedded systems.  Workstation applications using
+** SQLite normally do not need to invoke either of these routines.
 **
 ** A call to sqlite3_initialize() is an "effective" call if it is
 ** the first time sqlite3_initialize() is invoked during the lifetime of
 ** the process, or if it is the first time sqlite3_initialize() is invoked
-** following a call to sqlite3_shutdown().  Only an effective call
+** following a call to sqlite3_shutdown().  ^(Only an effective call
 ** of sqlite3_initialize() does any initialization.  All other calls
-** are harmless no-ops.
+** are harmless no-ops.)^
 **
-** Among other things, sqlite3_initialize() shall invoke
-** sqlite3_os_init().  Similarly, sqlite3_shutdown()
-** shall invoke sqlite3_os_end().
+** A call to sqlite3_shutdown() is an "effective" call if it is the first
+** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
+** an effective call to sqlite3_shutdown() does any deinitialization.
+** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
 **
-** The sqlite3_initialize() routine returns [SQLITE_OK] on success.
-** If for some reason, sqlite3_initialize() is unable to initialize
+** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
+** is not.  The sqlite3_shutdown() interface must only be called from a
+** single thread.  All open [database connections] must be closed and all
+** other SQLite resources must be deallocated prior to invoking
+** sqlite3_shutdown().
+**
+** Among other things, ^sqlite3_initialize() will invoke
+** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
+** will invoke sqlite3_os_end().
+**
+** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
+** ^If for some reason, sqlite3_initialize() is unable to initialize
 ** the library (perhaps it is unable to allocate a needed resource such
 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
 **
-** The sqlite3_initialize() routine is called internally by many other
+** ^The sqlite3_initialize() routine is called internally by many other
 ** SQLite interfaces so that an application usually does not need to
 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
 ** calls sqlite3_initialize() so the SQLite library will be automatically
 ** initialized when [sqlite3_open()] is called if it has not be initialized
-** already.  However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
+** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
 ** compile-time option, then the automatic calls to sqlite3_initialize()
 ** are omitted and the application must call sqlite3_initialize() directly
 ** prior to using any other SQLite interface.  For maximum portability,
@@ -1456,8 +1776,9 @@ struct sqlite3_vfs {
 ** interface is called automatically by sqlite3_initialize() and
 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
 ** implementations for sqlite3_os_init() and sqlite3_os_end()
-** are built into SQLite when it is compiled for unix, windows, or os/2.
-** When built for other platforms (using the [SQLITE_OS_OTHER=1] compile-time
+** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
+** When [custom builds | built for other platforms]
+** (using the [SQLITE_OS_OTHER=1] compile-time
 ** option) the application must supply a suitable implementation for
 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
 ** implementation of sqlite3_os_init() or sqlite3_os_end()
@@ -1470,8 +1791,7 @@ SQLITE_API int sqlite3_os_init(void);
 SQLITE_API int sqlite3_os_end(void);
 
 /*
-** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200>
-** EXPERIMENTAL
+** CAPI3REF: Configuring The SQLite Library
 **
 ** The sqlite3_config() interface is used to make global configuration
 ** changes to SQLite in order to tune SQLite to the specific needs of
@@ -1484,166 +1804,43 @@ SQLITE_API int sqlite3_os_end(void);
 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
 ** may only be invoked prior to library initialization using
 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
-** Note, however, that sqlite3_config() can be called as part of the
+** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
+** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
+** Note, however, that ^sqlite3_config() can be called as part of the
 ** implementation of an application-defined [sqlite3_os_init()].
 **
 ** The first argument to sqlite3_config() is an integer
-** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
+** [configuration option] that determines
 ** what property of SQLite is to be configured.  Subsequent arguments
-** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
+** vary depending on the [configuration option]
 ** in the first argument.
 **
-** When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
-** If the option is unknown or SQLite is unable to set the option
+** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
+** ^If the option is unknown or SQLite is unable to set the option
 ** then this routine returns a non-zero [error code].
-**
-** INVARIANTS:
-**
-** {H14103} A successful invocation of [sqlite3_config()] shall return
-**          [SQLITE_OK].
-**
-** {H14106} The [sqlite3_config()] interface shall return [SQLITE_MISUSE]
-**          if it is invoked in between calls to [sqlite3_initialize()] and
-**          [sqlite3_shutdown()].
-**
-** {H14120} A successful call to [sqlite3_config]([SQLITE_CONFIG_SINGLETHREAD])
-**          shall set the default [threading mode] to Single-thread.
-**
-** {H14123} A successful call to [sqlite3_config]([SQLITE_CONFIG_MULTITHREAD])
-**          shall set the default [threading mode] to Multi-thread.
-**
-** {H14126} A successful call to [sqlite3_config]([SQLITE_CONFIG_SERIALIZED])
-**          shall set the default [threading mode] to Serialized.
-**
-** {H14129} A successful call to [sqlite3_config]([SQLITE_CONFIG_MUTEX],X)
-**          where X is a pointer to an initialized [sqlite3_mutex_methods]
-**          object shall cause all subsequent mutex operations performed
-**          by SQLite to use the mutex methods that were present in X
-**          during the call to [sqlite3_config()].
-**
-** {H14132} A successful call to [sqlite3_config]([SQLITE_CONFIG_GETMUTEX],X)
-**          where X is a pointer to an [sqlite3_mutex_methods] object 
-**          shall overwrite the content of [sqlite3_mutex_methods] object
-**          with the mutex methods currently in use by SQLite.
-**
-** {H14135} A successful call to [sqlite3_config]([SQLITE_CONFIG_MALLOC],M)
-**          where M is a pointer to an initialized [sqlite3_mem_methods]
-**          object shall cause all subsequent memory allocation operations
-**          performed by SQLite to use the methods that were present in 
-**          M during the call to [sqlite3_config()].
-**
-** {H14138} A successful call to [sqlite3_config]([SQLITE_CONFIG_GETMALLOC],M)
-**          where M is a pointer to an [sqlite3_mem_methods] object shall
-**          overwrite the content of [sqlite3_mem_methods] object with 
-**          the memory allocation methods currently in use by
-**          SQLite.
-**
-** {H14141} A successful call to [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],1)
-**          shall enable the memory allocation status collection logic.
-**
-** {H14144} A successful call to [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],0)
-**          shall disable the memory allocation status collection logic.
-**
-** {H14147} The memory allocation status collection logic shall be
-**          enabled by default.
-**
-** {H14150} A successful call to [sqlite3_config]([SQLITE_CONFIG_SCRATCH],S,Z,N)
-**          where Z and N are non-negative integers and 
-**          S is a pointer to an aligned memory buffer not less than
-**          Z*N bytes in size shall cause S to be used by the
-**          [scratch memory allocator] for as many as N simulataneous
-**          allocations each of size (Z & ~7).
-**
-** {H14153} A successful call to [sqlite3_config]([SQLITE_CONFIG_SCRATCH],S,Z,N)
-**          where S is a NULL pointer shall disable the
-**          [scratch memory allocator].
-**
-** {H14156} A successful call to
-**          [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],S,Z,N)
-**          where Z and N are non-negative integers and 
-**          S is a pointer to an aligned memory buffer not less than
-**          Z*N bytes in size shall cause S to be used by the
-**          [pagecache memory allocator] for as many as N simulataneous
-**          allocations each of size (Z & ~7).
-**
-** {H14159} A successful call to
-**          [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],S,Z,N)
-**          where S is a NULL pointer shall disable the
-**          [pagecache memory allocator].
-**
-** {H14162} A successful call to [sqlite3_config]([SQLITE_CONFIG_HEAP],H,Z,N)
-**          where Z and N are non-negative integers and 
-**          H is a pointer to an aligned memory buffer not less than
-**          Z bytes in size shall enable the [memsys5] memory allocator
-**          and cause it to use buffer S as its memory source and to use
-**          a minimum allocation size of N.
-**
-** {H14165} A successful call to [sqlite3_config]([SQLITE_CONFIG_HEAP],H,Z,N)
-**          where H is a NULL pointer shall disable the
-**          [memsys5] memory allocator.
-**
-** {H14168} A successful call to [sqlite3_config]([SQLITE_CONFIG_LOOKASIDE],Z,N)
-**          shall cause the default [lookaside memory allocator] configuration
-**          for new [database connections] to be N slots of Z bytes each.
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_config(int, ...);
+SQLITE_API int sqlite3_config(int, ...);
 
 /*
-** CAPI3REF: Configure database connections  {H14200} <S20000>
-** EXPERIMENTAL
+** CAPI3REF: Configure database connections
 **
 ** The sqlite3_db_config() interface is used to make configuration
 ** changes to a [database connection].  The interface is similar to
 ** [sqlite3_config()] except that the changes apply to a single
-** [database connection] (specified in the first argument).  The
-** sqlite3_db_config() interface can only be used immediately after
-** the database connection is created using [sqlite3_open()],
-** [sqlite3_open16()], or [sqlite3_open_v2()].  
+** [database connection] (specified in the first argument).
 **
 ** The second argument to sqlite3_db_config(D,V,...)  is the
-** configuration verb - an integer code that indicates what
-** aspect of the [database connection] is being configured.
-** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE].
-** New verbs are likely to be added in future releases of SQLite.
-** Additional arguments depend on the verb.
-**
-** INVARIANTS:
-**
-** {H14203} A call to [sqlite3_db_config(D,V,...)] shall return [SQLITE_OK]
-**          if and only if the call is successful.
-**
-** {H14206} If one or more slots of the [lookaside memory allocator] for
-**          [database connection] D are in use, then a call to
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],...) shall
-**          fail with an [SQLITE_BUSY] return code.
-**
-** {H14209} A successful call to 
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],B,Z,N) where
-**          D is an open [database connection] and Z and N are positive
-**          integers and B is an aligned buffer at least Z*N bytes in size
-**          shall cause the [lookaside memory allocator] for D to use buffer B 
-**          with N slots of Z bytes each.
-**
-** {H14212} A successful call to 
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],B,Z,N) where
-**          D is an open [database connection] and Z and N are positive
-**          integers and B is NULL pointer shall cause the
-**          [lookaside memory allocator] for D to a obtain Z*N byte buffer
-**          from the primary memory allocator and use that buffer
-**          with N lookaside slots of Z bytes each.
-**
-** {H14215} A successful call to 
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],B,Z,N) where
-**          D is an open [database connection] and Z and N are zero shall
-**          disable the [lookaside memory allocator] for D.
-**
+** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 
+** that indicates what aspect of the [database connection] is being configured.
+** Subsequent arguments vary depending on the configuration verb.
 **
+** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
+** the call is considered successful.
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
+SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
 
 /*
-** CAPI3REF: Memory Allocation Routines {H10155} <S20120>
-** EXPERIMENTAL
+** CAPI3REF: Memory Allocation Routines
 **
 ** An instance of this object defines the interface between SQLite
 ** and low-level memory allocation routines.
@@ -1651,13 +1848,15 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** This object is used in only one place in the SQLite interface.
 ** A pointer to an instance of this object is the argument to
 ** [sqlite3_config()] when the configuration option is
-** [SQLITE_CONFIG_MALLOC].  By creating an instance of this object
-** and passing it to [sqlite3_config()] during configuration, an
-** application can specify an alternative memory allocation subsystem
-** for SQLite to use for all of its dynamic memory needs.
+** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].  
+** By creating an instance of this object
+** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
+** during configuration, an application can specify an alternative
+** memory allocation subsystem for SQLite to use for all of its
+** dynamic memory needs.
 **
-** Note that SQLite comes with a built-in memory allocator that is
-** perfectly adequate for the overwhelming majority of applications
+** Note that SQLite comes with several [built-in memory allocators]
+** that are perfectly adequate for the overwhelming majority of applications
 ** and that this object is only useful to a tiny minority of applications
 ** with specialized memory allocation requirements.  This object is
 ** also used during testing of SQLite in order to specify an alternative
@@ -1665,8 +1864,10 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** order to verify that SQLite recovers gracefully from such
 ** conditions.
 **
-** The xMalloc, xFree, and xRealloc methods must work like the
-** malloc(), free(), and realloc() functions from the standard library.
+** The xMalloc, xRealloc, and xFree methods must work like the
+** malloc(), realloc() and free() functions from the standard C library.
+** ^SQLite guarantees that the second argument to
+** xRealloc is always a value returned by a prior call to xRoundup.
 **
 ** xSize should return the allocated size of a memory allocation
 ** previously obtained from xMalloc or xRealloc.  The allocated size
@@ -1676,6 +1877,9 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** a memory allocation given a particular requested size.  Most memory
 ** allocators round up memory allocations at least to the next multiple
 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
+** Every memory allocation request coming in through [sqlite3_malloc()]
+** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0, 
+** that causes the corresponding memory allocation to fail.
 **
 ** The xInit method initializes the memory allocator.  (For example,
 ** it might allocate any require mutexes or initialize internal data
@@ -1683,6 +1887,20 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** [sqlite3_shutdown()] and should deallocate any resources acquired
 ** by xInit.  The pAppData pointer is used as the only parameter to
 ** xInit and xShutdown.
+**
+** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
+** the xInit method, so the xInit method need not be threadsafe.  The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  For all other methods, SQLite
+** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
+** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
+** it is by default) and so the methods are automatically serialized.
+** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
+** methods must be threadsafe or else make their own arrangements for
+** serialization.
+**
+** SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
 */
 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
 struct sqlite3_mem_methods {
@@ -1697,8 +1915,8 @@ struct sqlite3_mem_methods {
 };
 
 /*
-** CAPI3REF: Configuration Options {H10160} <S20000>
-** EXPERIMENTAL
+** CAPI3REF: Configuration Options
+** KEYWORDS: {configuration option}
 **
 ** These constants are the available integer configuration options that
 ** can be passed as the first argument to the [sqlite3_config()] interface.
@@ -1711,23 +1929,34 @@ struct sqlite3_mem_methods {
 ** is invoked.
 **
 ** <dl>
-** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
-** <dd>There are no arguments to this option.  This option disables
+** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Single-thread.  In other words, it disables
 ** all mutexing and puts SQLite into a mode where it can only be used
-** by a single thread.</dd>
+** by a single thread.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to change the [threading mode] from its default
+** value of Single-thread and so [sqlite3_config()] will return 
+** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
+** configuration option.</dd>
 **
-** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
-** <dd>There are no arguments to this option.  This option disables
+** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Multi-thread.  In other words, it disables
 ** mutexing on [database connection] and [prepared statement] objects.
 ** The application is responsible for serializing access to
 ** [database connections] and [prepared statements].  But other mutexes
 ** are enabled so that SQLite will be safe to use in a multi-threaded
 ** environment as long as no two threads attempt to use the same
-** [database connection] at the same time.  See the [threading mode]
-** documentation for additional information.</dd>
+** [database connection] at the same time.  ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Multi-thread [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
 **
-** <dt>SQLITE_CONFIG_SERIALIZED</dt>
-** <dd>There are no arguments to this option.  This option enables
+** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Serialized. In other words, this option enables
 ** all mutexes including the recursive
 ** mutexes on [database connection] and [prepared statement] objects.
 ** In this mode (which is the default when SQLite is compiled with
@@ -1735,112 +1964,179 @@ struct sqlite3_mem_methods {
 ** to [database connections] and [prepared statements] so that the
 ** application is free to use the same [database connection] or the
 ** same [prepared statement] in different threads at the same time.
-** See the [threading mode] documentation for additional information.</dd>
+** ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Serialized [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
 **
-** <dt>SQLITE_CONFIG_MALLOC</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mem_methods] structure.  The argument specifies
 ** alternative low-level memory allocation routines to be used in place of
-** the memory allocation routines built into SQLite.</dd>
+** the memory allocation routines built into SQLite.)^ ^SQLite makes
+** its own private copy of the content of the [sqlite3_mem_methods] structure
+** before the [sqlite3_config()] call returns.</dd>
 **
-** <dt>SQLITE_CONFIG_GETMALLOC</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
-** structure is filled with the currently defined memory allocation routines.
+** structure is filled with the currently defined memory allocation routines.)^
 ** This option can be used to overload the default memory allocation
 ** routines with a wrapper that simulations memory allocation failure or
-** tracks memory usage, for example.</dd>
+** tracks memory usage, for example. </dd>
 **
-** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
-** <dd>This option takes single argument of type int, interpreted as a 
+** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
+** <dd> ^This option takes single argument of type int, interpreted as a 
 ** boolean, which enables or disables the collection of memory allocation 
-** statistics. When disabled, the following SQLite interfaces become 
-** non-operational:
+** statistics. ^(When memory allocation statistics are disabled, the 
+** following SQLite interfaces become non-operational:
 **   <ul>
 **   <li> [sqlite3_memory_used()]
 **   <li> [sqlite3_memory_highwater()]
-**   <li> [sqlite3_soft_heap_limit()]
+**   <li> [sqlite3_soft_heap_limit64()]
 **   <li> [sqlite3_status()]
-**   </ul>
+**   </ul>)^
+** ^Memory allocation statistics are enabled by default unless SQLite is
+** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
+** allocation statistics are disabled by default.
 ** </dd>
 **
-** <dt>SQLITE_CONFIG_SCRATCH</dt>
-** <dd>This option specifies a static memory buffer that SQLite can use for
-** scratch memory.  There are three arguments:  A pointer to the memory, the
-** size of each scratch buffer (sz), and the number of buffers (N).  The sz
-** argument must be a multiple of 16. The sz parameter should be a few bytes
-** larger than the actual scratch space required due internal overhead.
-** The first
-** argument should point to an allocation of at least sz*N bytes of memory.
-** SQLite will use no more than one scratch buffer at once per thread, so
-** N should be set to the expected maximum number of threads.  The sz
-** parameter should be 6 times the size of the largest database page size.
-** Scratch buffers are used as part of the btree balance operation.  If
-** The btree balancer needs additional memory beyond what is provided by
-** scratch buffers or if no scratch buffer space is specified, then SQLite
-** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd>
+** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
+** <dd> ^This option specifies a static memory buffer that SQLite can use for
+** scratch memory.  There are three arguments:  A pointer an 8-byte
+** aligned memory buffer from which the scratch allocations will be
+** drawn, the size of each scratch allocation (sz),
+** and the maximum number of scratch allocations (N).  The sz
+** argument must be a multiple of 16.
+** The first argument must be a pointer to an 8-byte aligned buffer
+** of at least sz*N bytes of memory.
+** ^SQLite will use no more than two scratch buffers per thread.  So
+** N should be set to twice the expected maximum number of threads.
+** ^SQLite will never require a scratch buffer that is more than 6
+** times the database page size. ^If SQLite needs needs additional
+** scratch memory beyond what is provided by this configuration option, then 
+** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
 **
-** <dt>SQLITE_CONFIG_PAGECACHE</dt>
-** <dd>This option specifies a static memory buffer that SQLite can use for
-** the database page cache with the default page cache implemenation.  
+** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
+** <dd> ^This option specifies a static memory buffer that SQLite can use for
+** the database page cache with the default page cache implementation.  
 ** This configuration should not be used if an application-define page
-** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
-** There are three arguments to this option: A pointer to the
+** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
+** There are three arguments to this option: A pointer to 8-byte aligned
 ** memory, the size of each page buffer (sz), and the number of pages (N).
-** The sz argument must be a power of two between 512 and 32768.  The first
+** The sz argument should be the size of the largest database page
+** (a power of two between 512 and 32768) plus a little extra for each
+** page header.  ^The page header size is 20 to 40 bytes depending on
+** the host architecture.  ^It is harmless, apart from the wasted memory,
+** to make sz a little too large.  The first
 ** argument should point to an allocation of at least sz*N bytes of memory.
-** SQLite will use the memory provided by the first argument to satisfy its
-** memory needs for the first N pages that it adds to cache.  If additional
+** ^SQLite will use the memory provided by the first argument to satisfy its
+** memory needs for the first N pages that it adds to cache.  ^If additional
 ** page cache memory is needed beyond what is provided by this option, then
 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
-** The implementation might use one or more of the N buffers to hold 
-** memory accounting information. </dd>
+** The pointer in the first argument must
+** be aligned to an 8-byte boundary or subsequent behavior of SQLite
+** will be undefined.</dd>
 **
-** <dt>SQLITE_CONFIG_HEAP</dt>
-** <dd>This option specifies a static memory buffer that SQLite will use
+** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
+** <dd> ^This option specifies a static memory buffer that SQLite will use
 ** for all of its dynamic memory allocation needs beyond those provided
 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
-** There are three arguments: A pointer to the memory, the number of
-** bytes in the memory buffer, and the minimum allocation size.  If
-** the first pointer (the memory pointer) is NULL, then SQLite reverts
+** There are three arguments: An 8-byte aligned pointer to the memory,
+** the number of bytes in the memory buffer, and the minimum allocation size.
+** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
 ** to using its default memory allocator (the system malloc() implementation),
-** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  If the
+** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
-** allocator is engaged to handle all of SQLites memory allocation needs.</dd>
+** allocator is engaged to handle all of SQLites memory allocation needs.
+** The first pointer (the memory pointer) must be aligned to an 8-byte
+** boundary or subsequent behavior of SQLite will be undefined.
+** The minimum allocation size is capped at 2**12. Reasonable values
+** for the minimum allocation size are 2**5 through 2**8.</dd>
 **
-** <dt>SQLITE_CONFIG_MUTEX</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
 ** alternative low-level mutex routines to be used in place
-** the mutex routines built into SQLite.</dd>
+** the mutex routines built into SQLite.)^  ^SQLite makes a copy of the
+** content of the [sqlite3_mutex_methods] structure before the call to
+** [sqlite3_config()] returns. ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
 **
-** <dt>SQLITE_CONFIG_GETMUTEX</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mutex_methods] structure.  The
 ** [sqlite3_mutex_methods]
-** structure is filled with the currently defined mutex routines.
+** structure is filled with the currently defined mutex routines.)^
 ** This option can be used to overload the default mutex allocation
 ** routines with a wrapper used to track mutex usage for performance
-** profiling or testing, for example.</dd>
+** profiling or testing, for example.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
 **
-** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
-** <dd>This option takes two arguments that determine the default
-** memory allcation lookaside optimization.  The first argument is the
+** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
+** <dd> ^(This option takes two arguments that determine the default
+** memory allocation for the lookaside memory allocator on each
+** [database connection].  The first argument is the
 ** size of each lookaside buffer slot and the second is the number of
-** slots allocated to each database connection.</dd>
+** slots allocated to each database connection.)^  ^(This option sets the
+** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
+** verb to [sqlite3_db_config()] can be used to change the lookaside
+** configuration on individual connections.)^ </dd>
 **
-** <dt>SQLITE_CONFIG_PCACHE</dt>
-** <dd>This option takes a single argument which is a pointer to
-** an [sqlite3_pcache_methods] object.  This object specifies the interface
-** to a custom page cache implementation.  SQLite makes a copy of the
+** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
+** <dd> ^(This option takes a single argument which is a pointer to
+** an [sqlite3_pcache_methods2] object.  This object specifies the interface
+** to a custom page cache implementation.)^  ^SQLite makes a copy of the
 ** object and uses it for page cache memory allocations.</dd>
 **
-** <dt>SQLITE_CONFIG_GETPCACHE</dt>
-** <dd>This option takes a single argument which is a pointer to an
-** [sqlite3_pcache_methods] object.  SQLite copies of the current
-** page cache implementation into that object.</dd>
+** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
+** [sqlite3_pcache_methods2] object.  SQLite copies of the current
+** page cache implementation into that object.)^ </dd>
 **
+** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
+** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
+** function with a call signature of void(*)(void*,int,const char*), 
+** and a pointer to void. ^If the function pointer is not NULL, it is
+** invoked by [sqlite3_log()] to process each logging event.  ^If the
+** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
+** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
+** passed through as the first parameter to the application-defined logger
+** function whenever that function is invoked.  ^The second parameter to
+** the logger function is a copy of the first parameter to the corresponding
+** [sqlite3_log()] call and is intended to be a [result code] or an
+** [extended result code].  ^The third parameter passed to the logger is
+** log message after formatting via [sqlite3_snprintf()].
+** The SQLite logging interface is not reentrant; the logger function
+** supplied by the application must not invoke any SQLite interface.
+** In a multi-threaded application, the application-defined logger
+** function must be threadsafe. </dd>
+**
+** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
+** <dd> This option takes a single argument of type int. If non-zero, then
+** URI handling is globally enabled. If the parameter is zero, then URI handling
+** is globally disabled. If URI handling is globally enabled, all filenames
+** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
+** specified as part of [ATTACH] commands are interpreted as URIs, regardless
+** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
+** connection is opened. If it is globally disabled, filenames are
+** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
+** database connection is opened. By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** [SQLITE_USE_URI] symbol defined.
+**
+** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
+** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
+** <dd> These options are obsolete and should not be used by new code.
+** They are retained for backwards compatibility but are now no-ops.
 ** </dl>
 */
 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
@@ -1856,12 +2152,15 @@ struct sqlite3_mem_methods {
 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
-#define SQLITE_CONFIG_PCACHE       14  /* sqlite3_pcache_methods* */
-#define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
+#define SQLITE_CONFIG_PCACHE       14  /* no-op */
+#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
+#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
+#define SQLITE_CONFIG_URI          17  /* int */
+#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
 
 /*
-** CAPI3REF: Configuration Options {H10170} <S20000>
-** EXPERIMENTAL
+** CAPI3REF: Database Connection Configuration Options
 **
 ** These constants are the available integer configuration options that
 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
@@ -1869,322 +2168,295 @@ struct sqlite3_mem_methods {
 ** New configuration options may be added in future releases of SQLite.
 ** Existing configuration options might be discontinued.  Applications
 ** should check the return code from [sqlite3_db_config()] to make sure that
-** the call worked.  The [sqlite3_db_config()] interface will return a
+** the call worked.  ^The [sqlite3_db_config()] interface will return a
 ** non-zero [error code] if a discontinued or unsupported configuration option
 ** is invoked.
 **
 ** <dl>
 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
-** <dd>This option takes three additional arguments that determine the 
+** <dd> ^This option takes three additional arguments that determine the 
 ** [lookaside memory allocator] configuration for the [database connection].
-** The first argument (the third parameter to [sqlite3_db_config()] is a
-** pointer to a memory buffer to use for lookaside memory.  The first
-** argument may be NULL in which case SQLite will allocate the lookaside
-** buffer itself using [sqlite3_malloc()].  The second argument is the
-** size of each lookaside buffer slot and the third argument is the number of
+** ^The first argument (the third parameter to [sqlite3_db_config()] is a
+** pointer to a memory buffer to use for lookaside memory.
+** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
+** may be NULL in which case SQLite will allocate the
+** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
+** size of each lookaside buffer slot.  ^The third argument is the number of
 ** slots.  The size of the buffer in the first argument must be greater than
-** or equal to the product of the second and third arguments.</dd>
+** or equal to the product of the second and third arguments.  The buffer
+** must be aligned to an 8-byte boundary.  ^If the second argument to
+** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
+** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
+** configuration for a database connection can only be changed when that
+** connection is not currently using lookaside memory, or in other words
+** when the "current value" returned by
+** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
+** Any attempt to change the lookaside memory configuration when lookaside
+** memory is in use leaves the configuration unchanged and returns 
+** [SQLITE_BUSY].)^</dd>
+**
+** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
+** <dd> ^This option is used to enable or disable the enforcement of
+** [foreign key constraints].  There should be two additional arguments.
+** The first argument is an integer which is 0 to disable FK enforcement,
+** positive to enable FK enforcement or negative to leave FK enforcement
+** unchanged.  The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether FK enforcement is off or on
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the FK enforcement setting is not reported back. </dd>
+**
+** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
+** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
+** There should be two additional arguments.
+** The first argument is an integer which is 0 to disable triggers,
+** positive to enable triggers or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether triggers are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the trigger setting is not reported back. </dd>
 **
 ** </dl>
 */
-#define SQLITE_DBCONFIG_LOOKASIDE    1001  /* void* int int */
+#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
+#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
 
 
 /*
-** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700>
+** CAPI3REF: Enable Or Disable Extended Result Codes
 **
-** The sqlite3_extended_result_codes() routine enables or disables the
-** [extended result codes] feature of SQLite. The extended result
-** codes are disabled by default for historical compatibility considerations.
-**
-** INVARIANTS:
-**
-** {H12201} Each new [database connection] shall have the
-**          [extended result codes] feature disabled by default.
-**
-** {H12202} The [sqlite3_extended_result_codes(D,F)] interface shall enable
-**          [extended result codes] for the  [database connection] D
-**          if the F parameter is true, or disable them if F is false.
+** ^The sqlite3_extended_result_codes() routine enables or disables the
+** [extended result codes] feature of SQLite. ^The extended result
+** codes are disabled by default for historical compatibility.
 */
 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
 
 /*
-** CAPI3REF: Last Insert Rowid {H12220} <S10700>
+** CAPI3REF: Last Insert Rowid
 **
-** Each entry in an SQLite table has a unique 64-bit signed
-** integer key called the [ROWID | "rowid"]. The rowid is always available
+** ^Each entry in an SQLite table has a unique 64-bit signed
+** integer key called the [ROWID | "rowid"]. ^The rowid is always available
 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
-** names are not also used by explicitly declared columns. If
+** names are not also used by explicitly declared columns. ^If
 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
 ** is another alias for the rowid.
 **
-** This routine returns the [rowid] of the most recent
+** ^This routine returns the [rowid] of the most recent
 ** successful [INSERT] into the database from the [database connection]
-** in the first argument.  If no successful [INSERT]s
+** in the first argument.  ^As of SQLite version 3.7.7, this routines
+** records the last insert rowid of both ordinary tables and [virtual tables].
+** ^If no successful [INSERT]s
 ** have ever occurred on that database connection, zero is returned.
 **
-** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
-** row is returned by this routine as long as the trigger is running.
-** But once the trigger terminates, the value returned by this routine
-** reverts to the last value inserted before the trigger fired.
+** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
+** method, then this routine will return the [rowid] of the inserted
+** row as long as the trigger or virtual table method is running.
+** But once the trigger or virtual table method ends, the value returned 
+** by this routine reverts to what it was before the trigger or virtual
+** table method began.)^
 **
-** An [INSERT] that fails due to a constraint violation is not a
+** ^An [INSERT] that fails due to a constraint violation is not a
 ** successful [INSERT] and does not change the value returned by this
-** routine.  Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
+** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
 ** and INSERT OR ABORT make no changes to the return value of this
-** routine when their insertion fails.  When INSERT OR REPLACE
+** routine when their insertion fails.  ^(When INSERT OR REPLACE
 ** encounters a constraint violation, it does not fail.  The
 ** INSERT continues to completion after deleting rows that caused
 ** the constraint problem so INSERT OR REPLACE will always change
-** the return value of this interface.
+** the return value of this interface.)^
 **
-** For the purposes of this routine, an [INSERT] is considered to
+** ^For the purposes of this routine, an [INSERT] is considered to
 ** be successful even if it is subsequently rolled back.
 **
-** INVARIANTS:
+** This function is accessible to SQL statements via the
+** [last_insert_rowid() SQL function].
 **
-** {H12221} The [sqlite3_last_insert_rowid()] function shall return
-**          the [rowid]
-**          of the most recent successful [INSERT] performed on the same
-**          [database connection] and within the same or higher level
-**          trigger context, or zero if there have been no qualifying
-**          [INSERT] statements.
-**
-** {H12223} The [sqlite3_last_insert_rowid()] function shall return the
-**          same value when called from the same trigger context
-**          immediately before and after a [ROLLBACK].
-**
-** ASSUMPTIONS:
-**
-** {A12232} If a separate thread performs a new [INSERT] on the same
-**          database connection while the [sqlite3_last_insert_rowid()]
-**          function is running and thus changes the last insert [rowid],
-**          then the value returned by [sqlite3_last_insert_rowid()] is
-**          unpredictable and might not equal either the old or the new
-**          last insert [rowid].
+** If a separate thread performs a new [INSERT] on the same
+** database connection while the [sqlite3_last_insert_rowid()]
+** function is running and thus changes the last insert [rowid],
+** then the value returned by [sqlite3_last_insert_rowid()] is
+** unpredictable and might not equal either the old or the new
+** last insert [rowid].
 */
 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
 
 /*
-** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600>
+** CAPI3REF: Count The Number Of Rows Modified
 **
-** This function returns the number of database rows that were changed
+** ^This function returns the number of database rows that were changed
 ** or inserted or deleted by the most recently completed SQL statement
 ** on the [database connection] specified by the first parameter.
-** Only changes that are directly specified by the [INSERT], [UPDATE],
+** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
 ** or [DELETE] statement are counted.  Auxiliary changes caused by
-** triggers are not counted. Use the [sqlite3_total_changes()] function
-** to find the total number of changes including changes caused by triggers.
+** triggers or [foreign key actions] are not counted.)^ Use the
+** [sqlite3_total_changes()] function to find the total number of changes
+** including changes caused by triggers and foreign key actions.
 **
-** A "row change" is a change to a single row of a single table
+** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
+** are not counted.  Only real table changes are counted.
+**
+** ^(A "row change" is a change to a single row of a single table
 ** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
-** are changed as side effects of REPLACE constraint resolution,
-** rollback, ABORT processing, DROP TABLE, or by any other
-** mechanisms do not count as direct row changes.
+** are changed as side effects of [REPLACE] constraint resolution,
+** rollback, ABORT processing, [DROP TABLE], or by any other
+** mechanisms do not count as direct row changes.)^
 **
 ** A "trigger context" is a scope of execution that begins and
-** ends with the script of a trigger.  Most SQL statements are
+** ends with the script of a [CREATE TRIGGER | trigger]. 
+** Most SQL statements are
 ** evaluated outside of any trigger.  This is the "top level"
 ** trigger context.  If a trigger fires from the top level, a
 ** new trigger context is entered for the duration of that one
 ** trigger.  Subtriggers create subcontexts for their duration.
 **
-** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
+** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
 ** not create a new trigger context.
 **
-** This function returns the number of direct row changes in the
+** ^This function returns the number of direct row changes in the
 ** most recent INSERT, UPDATE, or DELETE statement within the same
 ** trigger context.
 **
-** Thus, when called from the top level, this function returns the
+** ^Thus, when called from the top level, this function returns the
 ** number of changes in the most recent INSERT, UPDATE, or DELETE
-** that also occurred at the top level.  Within the body of a trigger,
+** that also occurred at the top level.  ^(Within the body of a trigger,
 ** the sqlite3_changes() interface can be called to find the number of
 ** changes in the most recently completed INSERT, UPDATE, or DELETE
 ** statement within the body of the same trigger.
 ** However, the number returned does not include changes
-** caused by subtriggers since those have their own context.
+** caused by subtriggers since those have their own context.)^
 **
-** SQLite implements the command "DELETE FROM table" without a WHERE clause
-** by dropping and recreating the table.  Doing so is much faster than going
-** through and deleting individual elements from the table.  Because of this
-** optimization, the deletions in "DELETE FROM table" are not row changes and
-** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
-** functions, regardless of the number of elements that were originally
-** in the table.  To get an accurate count of the number of rows deleted, use
-** "DELETE FROM table WHERE 1" instead.  Or recompile using the
-** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the
-** optimization on all queries.
+** See also the [sqlite3_total_changes()] interface, the
+** [count_changes pragma], and the [changes() SQL function].
 **
-** INVARIANTS:
-**
-** {H12241} The [sqlite3_changes()] function shall return the number of
-**          row changes caused by the most recent INSERT, UPDATE,
-**          or DELETE statement on the same database connection and
-**          within the same or higher trigger context, or zero if there have
-**          not been any qualifying row changes.
-**
-** {H12243} Statements of the form "DELETE FROM tablename" with no
-**          WHERE clause shall cause subsequent calls to
-**          [sqlite3_changes()] to return zero, regardless of the
-**          number of rows originally in the table.
-**
-** ASSUMPTIONS:
-**
-** {A12252} If a separate thread makes changes on the same database connection
-**          while [sqlite3_changes()] is running then the value returned
-**          is unpredictable and not meaningful.
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_changes()] is running then the value returned
+** is unpredictable and not meaningful.
 */
 SQLITE_API int sqlite3_changes(sqlite3*);
 
 /*
-** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600>
+** CAPI3REF: Total Number Of Rows Modified
 **
-** This function returns the number of row changes caused by INSERT,
-** UPDATE or DELETE statements since the [database connection] was opened.
-** The count includes all changes from all trigger contexts.  However,
-** the count does not include changes used to implement REPLACE constraints,
-** do rollbacks or ABORT processing, or DROP table processing.
-** The changes are counted as soon as the statement that makes them is
-** completed (when the statement handle is passed to [sqlite3_reset()] or
-** [sqlite3_finalize()]).
+** ^This function returns the number of row changes caused by [INSERT],
+** [UPDATE] or [DELETE] statements since the [database connection] was opened.
+** ^(The count returned by sqlite3_total_changes() includes all changes
+** from all [CREATE TRIGGER | trigger] contexts and changes made by
+** [foreign key actions]. However,
+** the count does not include changes used to implement [REPLACE] constraints,
+** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The
+** count does not include rows of views that fire an [INSTEAD OF trigger],
+** though if the INSTEAD OF trigger makes changes of its own, those changes 
+** are counted.)^
+** ^The sqlite3_total_changes() function counts the changes as soon as
+** the statement that makes them is completed (when the statement handle
+** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
 **
-** SQLite implements the command "DELETE FROM table" without a WHERE clause
-** by dropping and recreating the table.  (This is much faster than going
-** through and deleting individual elements from the table.)  Because of this
-** optimization, the deletions in "DELETE FROM table" are not row changes and
-** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
-** functions, regardless of the number of elements that were originally
-** in the table.  To get an accurate count of the number of rows deleted, use
-** "DELETE FROM table WHERE 1" instead.   Or recompile using the
-** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the
-** optimization on all queries.
+** See also the [sqlite3_changes()] interface, the
+** [count_changes pragma], and the [total_changes() SQL function].
 **
-** See also the [sqlite3_changes()] interface.
-**
-** INVARIANTS:
-**
-** {H12261} The [sqlite3_total_changes()] returns the total number
-**          of row changes caused by INSERT, UPDATE, and/or DELETE
-**          statements on the same [database connection], in any
-**          trigger context, since the database connection was created.
-**
-** {H12263} Statements of the form "DELETE FROM tablename" with no
-**          WHERE clause shall not change the value returned
-**          by [sqlite3_total_changes()].
-**
-** ASSUMPTIONS:
-**
-** {A12264} If a separate thread makes changes on the same database connection
-**          while [sqlite3_total_changes()] is running then the value
-**          returned is unpredictable and not meaningful.
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_total_changes()] is running then the value
+** returned is unpredictable and not meaningful.
 */
 SQLITE_API int sqlite3_total_changes(sqlite3*);
 
 /*
-** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500>
+** CAPI3REF: Interrupt A Long-Running Query
 **
-** This function causes any pending database operation to abort and
+** ^This function causes any pending database operation to abort and
 ** return at its earliest opportunity. This routine is typically
 ** called in response to a user action such as pressing "Cancel"
 ** or Ctrl-C where the user wants a long query operation to halt
 ** immediately.
 **
-** It is safe to call this routine from a thread different from the
+** ^It is safe to call this routine from a thread different from the
 ** thread that is currently running the database operation.  But it
 ** is not safe to call this routine with a [database connection] that
 ** is closed or might close before sqlite3_interrupt() returns.
 **
-** If an SQL operation is very nearly finished at the time when
+** ^If an SQL operation is very nearly finished at the time when
 ** sqlite3_interrupt() is called, then it might not have an opportunity
 ** to be interrupted and might continue to completion.
 **
-** An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
-** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
+** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
+** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
 ** that is inside an explicit transaction, then the entire transaction
 ** will be rolled back automatically.
 **
-** A call to sqlite3_interrupt() has no effect on SQL statements
-** that are started after sqlite3_interrupt() returns.
+** ^The sqlite3_interrupt(D) call is in effect until all currently running
+** SQL statements on [database connection] D complete.  ^Any new SQL statements
+** that are started after the sqlite3_interrupt() call and before the 
+** running statements reaches zero are interrupted as if they had been
+** running prior to the sqlite3_interrupt() call.  ^New SQL statements
+** that are started after the running statement count reaches zero are
+** not effected by the sqlite3_interrupt().
+** ^A call to sqlite3_interrupt(D) that occurs when there are no running
+** SQL statements is a no-op and has no effect on SQL statements
+** that are started after the sqlite3_interrupt() call returns.
 **
-** INVARIANTS:
-**
-** {H12271} The [sqlite3_interrupt()] interface will force all running
-**          SQL statements associated with the same database connection
-**          to halt after processing at most one additional row of data.
-**
-** {H12272} Any SQL statement that is interrupted by [sqlite3_interrupt()]
-**          will return [SQLITE_INTERRUPT].
-**
-** ASSUMPTIONS:
-**
-** {A12279} If the database connection closes while [sqlite3_interrupt()]
-**          is running then bad things will likely happen.
+** If the database connection closes while [sqlite3_interrupt()]
+** is running then bad things will likely happen.
 */
 SQLITE_API void sqlite3_interrupt(sqlite3*);
 
 /*
-** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200>
+** CAPI3REF: Determine If An SQL Statement Is Complete
 **
-** These routines are useful for command-line input to determine if the
-** currently entered text seems to form complete a SQL statement or
+** These routines are useful during command-line input to determine if the
+** currently entered text seems to form a complete SQL statement or
 ** if additional input is needed before sending the text into
-** SQLite for parsing.  These routines return true if the input string
-** appears to be a complete SQL statement.  A statement is judged to be
-** complete if it ends with a semicolon token and is not a fragment of a
-** CREATE TRIGGER statement.  Semicolons that are embedded within
+** SQLite for parsing.  ^These routines return 1 if the input string
+** appears to be a complete SQL statement.  ^A statement is judged to be
+** complete if it ends with a semicolon token and is not a prefix of a
+** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
 ** string literals or quoted identifier names or comments are not
 ** independent tokens (they are part of the token in which they are
-** embedded) and thus do not count as a statement terminator.
+** embedded) and thus do not count as a statement terminator.  ^Whitespace
+** and comments that follow the final semicolon are ignored.
 **
-** These routines do not parse the SQL statements thus
+** ^These routines return 0 if the statement is incomplete.  ^If a
+** memory allocation fails, then SQLITE_NOMEM is returned.
+**
+** ^These routines do not parse the SQL statements thus
 ** will not detect syntactically incorrect SQL.
 **
-** INVARIANTS:
+** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 
+** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
+** automatically by sqlite3_complete16().  If that initialization fails,
+** then the return value from sqlite3_complete16() will be non-zero
+** regardless of whether or not the input SQL is complete.)^
 **
-** {H10511} A successful evaluation of [sqlite3_complete()] or
-**          [sqlite3_complete16()] functions shall
-**          return a numeric 1 if and only if the last non-whitespace
-**          token in their input is a semicolon that is not in between
-**          the BEGIN and END of a CREATE TRIGGER statement.
+** The input to [sqlite3_complete()] must be a zero-terminated
+** UTF-8 string.
 **
-** {H10512} If a memory allocation error occurs during an invocation
-**          of [sqlite3_complete()] or [sqlite3_complete16()] then the
-**          routine shall return [SQLITE_NOMEM].
-**
-** ASSUMPTIONS:
-**
-** {A10512} The input to [sqlite3_complete()] must be a zero-terminated
-**          UTF-8 string.
-**
-** {A10513} The input to [sqlite3_complete16()] must be a zero-terminated
-**          UTF-16 string in native byte order.
+** The input to [sqlite3_complete16()] must be a zero-terminated
+** UTF-16 string in native byte order.
 */
 SQLITE_API int sqlite3_complete(const char *sql);
 SQLITE_API int sqlite3_complete16(const void *sql);
 
 /*
-** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400>
+** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
 **
-** This routine sets a callback function that might be invoked whenever
+** ^This routine sets a callback function that might be invoked whenever
 ** an attempt is made to open a database table that another thread
 ** or process has locked.
 **
-** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
-** is returned immediately upon encountering the lock. If the busy callback
-** is not NULL, then the callback will be invoked with two arguments.
+** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
+** is returned immediately upon encountering the lock.  ^If the busy callback
+** is not NULL, then the callback might be invoked with two arguments.
 **
-** The first argument to the handler is a copy of the void* pointer which
-** is the third argument to sqlite3_busy_handler().  The second argument to
-** the handler callback is the number of times that the busy handler has
-** been invoked for this locking event.  If the
+** ^The first argument to the busy handler is a copy of the void* pointer which
+** is the third argument to sqlite3_busy_handler().  ^The second argument to
+** the busy handler callback is the number of times that the busy handler has
+** been invoked for this locking event.  ^If the
 ** busy callback returns 0, then no additional attempts are made to
 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
-** If the callback returns non-zero, then another attempt
+** ^If the callback returns non-zero, then another attempt
 ** is made to open the database for reading and the cycle repeats.
 **
 ** The presence of a busy handler does not guarantee that it will be invoked
-** when there is lock contention. If SQLite determines that invoking the busy
+** when there is lock contention. ^If SQLite determines that invoking the busy
 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
 ** Consider a scenario where one process is holding a read lock that
@@ -2198,99 +2470,62 @@ SQLITE_API int sqlite3_complete16(const void *sql);
 ** will induce the first process to release its read lock and allow
 ** the second process to proceed.
 **
-** The default busy callback is NULL.
+** ^The default busy callback is NULL.
 **
-** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
+** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
 ** when SQLite is in the middle of a large transaction where all the
 ** changes will not fit into the in-memory cache.  SQLite will
 ** already hold a RESERVED lock on the database file, but it needs
 ** to promote this lock to EXCLUSIVE so that it can spill cache
 ** pages into the database file without harm to concurrent
-** readers.  If it is unable to promote the lock, then the in-memory
+** readers.  ^If it is unable to promote the lock, then the in-memory
 ** cache will be left in an inconsistent state and so the error
 ** code is promoted from the relatively benign [SQLITE_BUSY] to
-** the more severe [SQLITE_IOERR_BLOCKED].  This error code promotion
+** the more severe [SQLITE_IOERR_BLOCKED].  ^This error code promotion
 ** forces an automatic rollback of the changes.  See the
 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
 ** this is important.
 **
-** There can only be a single busy handler defined for each
+** ^(There can only be a single busy handler defined for each
 ** [database connection].  Setting a new busy handler clears any
-** previously set handler.  Note that calling [sqlite3_busy_timeout()]
+** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
 ** will also set or clear the busy handler.
 **
 ** The busy callback should not take any actions which modify the
 ** database connection that invoked the busy handler.  Any such actions
 ** result in undefined behavior.
 ** 
-** INVARIANTS:
-**
-** {H12311} The [sqlite3_busy_handler(D,C,A)] function shall replace
-**          busy callback in the [database connection] D with a new
-**          a new busy handler C and application data pointer A.
-**
-** {H12312} Newly created [database connections] shall have a busy
-**          handler of NULL.
-**
-** {H12314} When two or more [database connections] share a
-**          [sqlite3_enable_shared_cache | common cache],
-**          the busy handler for the database connection currently using
-**          the cache shall be invoked when the cache encounters a lock.
-**
-** {H12316} If a busy handler callback returns zero, then the SQLite interface
-**          that provoked the locking event shall return [SQLITE_BUSY].
-**
-** {H12318} SQLite shall invokes the busy handler with two arguments which
-**          are a copy of the pointer supplied by the 3rd parameter to
-**          [sqlite3_busy_handler()] and a count of the number of prior
-**          invocations of the busy handler for the same locking event.
-**
-** ASSUMPTIONS:
-**
-** {A12319} A busy handler must not close the database connection
-**          or [prepared statement] that invoked the busy handler.
+** A busy handler must not close the database connection
+** or [prepared statement] that invoked the busy handler.
 */
 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
 
 /*
-** CAPI3REF: Set A Busy Timeout {H12340} <S40410>
+** CAPI3REF: Set A Busy Timeout
 **
-** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
-** for a specified amount of time when a table is locked.  The handler
+** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
+** for a specified amount of time when a table is locked.  ^The handler
 ** will sleep multiple times until at least "ms" milliseconds of sleeping
-** have accumulated. {H12343} After "ms" milliseconds of sleeping,
+** have accumulated.  ^After at least "ms" milliseconds of sleeping,
 ** the handler returns 0 which causes [sqlite3_step()] to return
 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
 **
-** Calling this routine with an argument less than or equal to zero
+** ^Calling this routine with an argument less than or equal to zero
 ** turns off all busy handlers.
 **
-** There can only be a single busy handler for a particular
+** ^(There can only be a single busy handler for a particular
 ** [database connection] any any given moment.  If another busy handler
 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
-** this routine, that other busy handler is cleared.
-**
-** INVARIANTS:
-**
-** {H12341} The [sqlite3_busy_timeout()] function shall override any prior
-**          [sqlite3_busy_timeout()] or [sqlite3_busy_handler()] setting
-**          on the same [database connection].
-**
-** {H12343} If the 2nd parameter to [sqlite3_busy_timeout()] is less than
-**          or equal to zero, then the busy handler shall be cleared so that
-**          all subsequent locking events immediately return [SQLITE_BUSY].
-**
-** {H12344} If the 2nd parameter to [sqlite3_busy_timeout()] is a positive
-**          number N, then a busy handler shall be set that repeatedly calls
-**          the xSleep() method in the [sqlite3_vfs | VFS interface] until
-**          either the lock clears or until the cumulative sleep time
-**          reported back by xSleep() exceeds N milliseconds.
+** this routine, that other busy handler is cleared.)^
 */
 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
 
 /*
-** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000>
+** CAPI3REF: Convenience Routines For Running Queries
+**
+** This is a legacy interface that is preserved for backwards compatibility.
+** Use of this interface is not recommended.
 **
 ** Definition: A <b>result table</b> is memory data structure created by the
 ** [sqlite3_get_table()] interface.  A result table records the
@@ -2312,7 +2547,7 @@ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
 ** It is not safe to pass a result table directly to [sqlite3_free()].
 ** A result table should be deallocated using [sqlite3_free_table()].
 **
-** As an example of the result table format, suppose a query result
+** ^(As an example of the result table format, suppose a query result
 ** is as follows:
 **
 ** <blockquote><pre>
@@ -2336,15 +2571,15 @@ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
 **        azResult&#91;5] = "28";
 **        azResult&#91;6] = "Cindy";
 **        azResult&#91;7] = "21";
-** </pre></blockquote>
+** </pre></blockquote>)^
 **
-** The sqlite3_get_table() function evaluates one or more
+** ^The sqlite3_get_table() function evaluates one or more
 ** semicolon-separated SQL statements in the zero-terminated UTF-8
-** string of its 2nd parameter.  It returns a result table to the
+** string of its 2nd parameter and returns a result table to the
 ** pointer given in its 3rd parameter.
 **
-** After the calling function has finished using the result, it should
-** pass the pointer to the result table to sqlite3_free_table() in order to
+** After the application has finished with the result from sqlite3_get_table(),
+** it must pass the result table pointer to sqlite3_free_table() in order to
 ** release the memory that was malloced.  Because of the way the
 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
 ** function must not try to call [sqlite3_free()] directly.  Only
@@ -2355,40 +2590,8 @@ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
 ** to any internal data structures of SQLite.  It uses only the public
 ** interface defined here.  As a consequence, errors that occur in the
 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
-** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()].
-**
-** INVARIANTS:
-**
-** {H12371} If a [sqlite3_get_table()] fails a memory allocation, then
-**          it shall free the result table under construction, abort the
-**          query in process, skip any subsequent queries, set the
-**          *pazResult output pointer to NULL and return [SQLITE_NOMEM].
-**
-** {H12373} If the pnColumn parameter to [sqlite3_get_table()] is not NULL
-**          then a successful invocation of [sqlite3_get_table()] shall
-**          write the number of columns in the
-**          result set of the query into *pnColumn.
-**
-** {H12374} If the pnRow parameter to [sqlite3_get_table()] is not NULL
-**          then a successful invocation of [sqlite3_get_table()] shall
-**          writes the number of rows in the
-**          result set of the query into *pnRow.
-**
-** {H12376} A successful invocation of [sqlite3_get_table()] that computes
-**          N rows of result with C columns per row shall make *pazResult
-**          point to an array of pointers to (N+1)*C strings where the first
-**          C strings are column names as obtained from
-**          [sqlite3_column_name()] and the rest are column result values
-**          obtained from [sqlite3_column_text()].
-**
-** {H12379} The values in the pazResult array returned by [sqlite3_get_table()]
-**          shall remain valid until cleared by [sqlite3_free_table()].
-**
-** {H12382} When an error occurs during evaluation of [sqlite3_get_table()]
-**          the function shall set *pazResult to NULL, write an error message
-**          into memory obtained from [sqlite3_malloc()], make
-**          **pzErrmsg point to that error message, and return a
-**          appropriate [error code].
+** reflected in subsequent calls to [sqlite3_errcode()] or
+** [sqlite3_errmsg()].
 */
 SQLITE_API int sqlite3_get_table(
   sqlite3 *db,          /* An open database */
@@ -2401,45 +2604,47 @@ SQLITE_API int sqlite3_get_table(
 SQLITE_API void sqlite3_free_table(char **result);
 
 /*
-** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000>
+** CAPI3REF: Formatted String Printing Functions
 **
-** These routines are workalikes of the "printf()" family of functions
+** These routines are work-alikes of the "printf()" family of functions
 ** from the standard C library.
 **
-** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
+** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
 ** results into memory obtained from [sqlite3_malloc()].
 ** The strings returned by these two routines should be
-** released by [sqlite3_free()].  Both routines return a
+** released by [sqlite3_free()].  ^Both routines return a
 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
 ** memory to hold the resulting string.
 **
-** In sqlite3_snprintf() routine is similar to "snprintf()" from
+** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
 ** the standard C library.  The result is written into the
 ** buffer supplied as the second parameter whose size is given by
 ** the first parameter. Note that the order of the
-** first two parameters is reversed from snprintf().  This is an
+** first two parameters is reversed from snprintf().)^  This is an
 ** historical accident that cannot be fixed without breaking
-** backwards compatibility.  Note also that sqlite3_snprintf()
+** backwards compatibility.  ^(Note also that sqlite3_snprintf()
 ** returns a pointer to its buffer instead of the number of
-** characters actually written into the buffer.  We admit that
+** characters actually written into the buffer.)^  We admit that
 ** the number of characters written would be a more useful return
 ** value but we cannot change the implementation of sqlite3_snprintf()
 ** now without breaking compatibility.
 **
-** As long as the buffer size is greater than zero, sqlite3_snprintf()
-** guarantees that the buffer is always zero-terminated.  The first
+** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
+** guarantees that the buffer is always zero-terminated.  ^The first
 ** parameter "n" is the total size of the buffer, including space for
 ** the zero terminator.  So the longest string that can be completely
 ** written will be n-1 characters.
 **
+** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
+**
 ** These routines all implement some additional formatting
 ** options that are useful for constructing SQL statements.
 ** All of the usual printf() formatting options apply.  In addition, there
 ** is are "%q", "%Q", and "%z" options.
 **
-** The %q option works like %s in that it substitutes a null-terminated
+** ^(The %q option works like %s in that it substitutes a nul-terminated
 ** string from the argument list.  But %q also doubles every '\'' character.
-** %q is designed for use inside a string literal.  By doubling each '\''
+** %q is designed for use inside a string literal.)^  By doubling each '\''
 ** character it escapes that character and allows it to be inserted into
 ** the string.
 **
@@ -2474,10 +2679,10 @@ SQLITE_API void sqlite3_free_table(char **result);
 ** This second example is an SQL syntax error.  As a general rule you should
 ** always use %q instead of %s when inserting text into a string literal.
 **
-** The %Q option works like %q except it also adds single quotes around
+** ^(The %Q option works like %q except it also adds single quotes around
 ** the outside of the total string.  Additionally, if the parameter in the
 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
-** single quotes) in place of the %Q option.  So, for example, one could say:
+** single quotes).)^  So, for example, one could say:
 **
 ** <blockquote><pre>
 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
@@ -2488,49 +2693,33 @@ SQLITE_API void sqlite3_free_table(char **result);
 ** The code above will render a correct SQL statement in the zSQL
 ** variable even if the zText variable is a NULL pointer.
 **
-** The "%z" formatting option works exactly like "%s" with the
+** ^(The "%z" formatting option works like "%s" but with the
 ** addition that after the string has been read and copied into
-** the result, [sqlite3_free()] is called on the input string. {END}
-**
-** INVARIANTS:
-**
-** {H17403}  The [sqlite3_mprintf()] and [sqlite3_vmprintf()] interfaces
-**           return either pointers to zero-terminated UTF-8 strings held in
-**           memory obtained from [sqlite3_malloc()] or NULL pointers if
-**           a call to [sqlite3_malloc()] fails.
-**
-** {H17406}  The [sqlite3_snprintf()] interface writes a zero-terminated
-**           UTF-8 string into the buffer pointed to by the second parameter
-**           provided that the first parameter is greater than zero.
-**
-** {H17407}  The [sqlite3_snprintf()] interface does not write slots of
-**           its output buffer (the second parameter) outside the range
-**           of 0 through N-1 (where N is the first parameter)
-**           regardless of the length of the string
-**           requested by the format specification.
+** the result, [sqlite3_free()] is called on the input string.)^
 */
 SQLITE_API char *sqlite3_mprintf(const char*,...);
 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
+SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
 
 /*
-** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000>
+** CAPI3REF: Memory Allocation Subsystem
 **
-** The SQLite core  uses these three routines for all of its own
+** The SQLite core uses these three routines for all of its own
 ** internal memory allocation needs. "Core" in the previous sentence
 ** does not include operating-system specific VFS implementation.  The
 ** Windows VFS uses native malloc() and free() for some operations.
 **
-** The sqlite3_malloc() routine returns a pointer to a block
+** ^The sqlite3_malloc() routine returns a pointer to a block
 ** of memory at least N bytes in length, where N is the parameter.
-** If sqlite3_malloc() is unable to obtain sufficient free
-** memory, it returns a NULL pointer.  If the parameter N to
+** ^If sqlite3_malloc() is unable to obtain sufficient free
+** memory, it returns a NULL pointer.  ^If the parameter N to
 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
 ** a NULL pointer.
 **
-** Calling sqlite3_free() with a pointer previously returned
+** ^Calling sqlite3_free() with a pointer previously returned
 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
-** that it might be reused.  The sqlite3_free() routine is
+** that it might be reused.  ^The sqlite3_free() routine is
 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
 ** to sqlite3_free() is harmless.  After being freed, memory
 ** should neither be read nor written.  Even reading previously freed
@@ -2539,137 +2728,82 @@ SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
 ** might result if sqlite3_free() is called with a non-NULL pointer that
 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
 **
-** The sqlite3_realloc() interface attempts to resize a
+** ^(The sqlite3_realloc() interface attempts to resize a
 ** prior memory allocation to be at least N bytes, where N is the
 ** second parameter.  The memory allocation to be resized is the first
-** parameter.  If the first parameter to sqlite3_realloc()
+** parameter.)^ ^ If the first parameter to sqlite3_realloc()
 ** is a NULL pointer then its behavior is identical to calling
 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
-** If the second parameter to sqlite3_realloc() is zero or
+** ^If the second parameter to sqlite3_realloc() is zero or
 ** negative then the behavior is exactly the same as calling
 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
-** sqlite3_realloc() returns a pointer to a memory allocation
+** ^sqlite3_realloc() returns a pointer to a memory allocation
 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
-** If M is the size of the prior allocation, then min(N,M) bytes
+** ^If M is the size of the prior allocation, then min(N,M) bytes
 ** of the prior allocation are copied into the beginning of buffer returned
 ** by sqlite3_realloc() and the prior allocation is freed.
-** If sqlite3_realloc() returns NULL, then the prior allocation
+** ^If sqlite3_realloc() returns NULL, then the prior allocation
 ** is not freed.
 **
-** The memory returned by sqlite3_malloc() and sqlite3_realloc()
-** is always aligned to at least an 8 byte boundary. {END}
-**
-** The default implementation of the memory allocation subsystem uses
-** the malloc(), realloc() and free() provided by the standard C library.
-** {H17382} However, if SQLite is compiled with the
-** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i>
-** is an integer), then SQLite create a static array of at least
-** <i>NNN</i> bytes in size and uses that array for all of its dynamic
-** memory allocation needs. {END}  Additional memory allocator options
-** may be added in future releases.
+** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
+** is always aligned to at least an 8 byte boundary, or to a
+** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
+** option is used.
 **
 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
 ** implementation of these routines to be omitted.  That capability
 ** is no longer provided.  Only built-in memory allocators can be used.
 **
-** The Windows OS interface layer calls
+** Prior to SQLite version 3.7.10, the Windows OS interface layer called
 ** the system malloc() and free() directly when converting
 ** filenames between the UTF-8 encoding used by SQLite
 ** and whatever filename encoding is used by the particular Windows
-** installation.  Memory allocation errors are detected, but
-** they are reported back as [SQLITE_CANTOPEN] or
+** installation.  Memory allocation errors were detected, but
+** they were reported back as [SQLITE_CANTOPEN] or
 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
 **
-** INVARIANTS:
+** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
+** must be either NULL or else pointers obtained from a prior
+** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
+** not yet been released.
 **
-** {H17303}  The [sqlite3_malloc(N)] interface returns either a pointer to
-**           a newly checked-out block of at least N bytes of memory
-**           that is 8-byte aligned, or it returns NULL if it is unable
-**           to fulfill the request.
-**
-** {H17304}  The [sqlite3_malloc(N)] interface returns a NULL pointer if
-**           N is less than or equal to zero.
-**
-** {H17305}  The [sqlite3_free(P)] interface releases memory previously
-**           returned from [sqlite3_malloc()] or [sqlite3_realloc()],
-**           making it available for reuse.
-**
-** {H17306}  A call to [sqlite3_free(NULL)] is a harmless no-op.
-**
-** {H17310}  A call to [sqlite3_realloc(0,N)] is equivalent to a call
-**           to [sqlite3_malloc(N)].
-**
-** {H17312}  A call to [sqlite3_realloc(P,0)] is equivalent to a call
-**           to [sqlite3_free(P)].
-**
-** {H17315}  The SQLite core uses [sqlite3_malloc()], [sqlite3_realloc()],
-**           and [sqlite3_free()] for all of its memory allocation and
-**           deallocation needs.
-**
-** {H17318}  The [sqlite3_realloc(P,N)] interface returns either a pointer
-**           to a block of checked-out memory of at least N bytes in size
-**           that is 8-byte aligned, or a NULL pointer.
-**
-** {H17321}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
-**           copies the first K bytes of content from P into the newly
-**           allocated block, where K is the lesser of N and the size of
-**           the buffer P.
-**
-** {H17322}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
-**           releases the buffer P.
-**
-** {H17323}  When [sqlite3_realloc(P,N)] returns NULL, the buffer P is
-**           not modified or released.
-**
-** ASSUMPTIONS:
-**
-** {A17350}  The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
-**           must be either NULL or else pointers obtained from a prior
-**           invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
-**           not yet been released.
-**
-** {A17351}  The application must not read or write any part of
-**           a block of memory after it has been released using
-**           [sqlite3_free()] or [sqlite3_realloc()].
+** The application must not read or write any part of
+** a block of memory after it has been released using
+** [sqlite3_free()] or [sqlite3_realloc()].
 */
 SQLITE_API void *sqlite3_malloc(int);
 SQLITE_API void *sqlite3_realloc(void*, int);
 SQLITE_API void sqlite3_free(void*);
 
 /*
-** CAPI3REF: Memory Allocator Statistics {H17370} <S30210>
+** CAPI3REF: Memory Allocator Statistics
 **
 ** SQLite provides these two interfaces for reporting on the status
 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
 ** routines, which form the built-in memory allocation subsystem.
 **
-** INVARIANTS:
+** ^The [sqlite3_memory_used()] routine returns the number of bytes
+** of memory currently outstanding (malloced but not freed).
+** ^The [sqlite3_memory_highwater()] routine returns the maximum
+** value of [sqlite3_memory_used()] since the high-water mark
+** was last reset.  ^The values returned by [sqlite3_memory_used()] and
+** [sqlite3_memory_highwater()] include any overhead
+** added by SQLite in its implementation of [sqlite3_malloc()],
+** but not overhead added by the any underlying system library
+** routines that [sqlite3_malloc()] may call.
 **
-** {H17371} The [sqlite3_memory_used()] routine returns the number of bytes
-**          of memory currently outstanding (malloced but not freed).
-**
-** {H17373} The [sqlite3_memory_highwater()] routine returns the maximum
-**          value of [sqlite3_memory_used()] since the high-water mark
-**          was last reset.
-**
-** {H17374} The values returned by [sqlite3_memory_used()] and
-**          [sqlite3_memory_highwater()] include any overhead
-**          added by SQLite in its implementation of [sqlite3_malloc()],
-**          but not overhead added by the any underlying system library
-**          routines that [sqlite3_malloc()] may call.
-**
-** {H17375} The memory high-water mark is reset to the current value of
-**          [sqlite3_memory_used()] if and only if the parameter to
-**          [sqlite3_memory_highwater()] is true.  The value returned
-**          by [sqlite3_memory_highwater(1)] is the high-water mark
-**          prior to the reset.
+** ^The memory high-water mark is reset to the current value of
+** [sqlite3_memory_used()] if and only if the parameter to
+** [sqlite3_memory_highwater()] is true.  ^The value returned
+** by [sqlite3_memory_highwater(1)] is the high-water mark
+** prior to the reset.
 */
 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
 
 /*
-** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000>
+** CAPI3REF: Pseudo-Random Number Generator
 **
 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
 ** select random [ROWID | ROWIDs] when inserting new records into a table that
@@ -2677,59 +2811,59 @@ SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
 ** the build-in random() and randomblob() SQL functions.  This interface allows
 ** applications to access the same PRNG for other purposes.
 **
-** A call to this routine stores N bytes of randomness into buffer P.
+** ^A call to this routine stores N bytes of randomness into buffer P.
 **
-** The first time this routine is invoked (either internally or by
+** ^The first time this routine is invoked (either internally or by
 ** the application) the PRNG is seeded using randomness obtained
 ** from the xRandomness method of the default [sqlite3_vfs] object.
-** On all subsequent invocations, the pseudo-randomness is generated
+** ^On all subsequent invocations, the pseudo-randomness is generated
 ** internally and without recourse to the [sqlite3_vfs] xRandomness
 ** method.
-**
-** INVARIANTS:
-**
-** {H17392} The [sqlite3_randomness(N,P)] interface writes N bytes of
-**          high-quality pseudo-randomness into buffer P.
 */
 SQLITE_API void sqlite3_randomness(int N, void *P);
 
 /*
-** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100>
+** CAPI3REF: Compile-Time Authorization Callbacks
 **
-** This routine registers a authorizer callback with a particular
+** ^This routine registers an authorizer callback with a particular
 ** [database connection], supplied in the first argument.
-** The authorizer callback is invoked as SQL statements are being compiled
+** ^The authorizer callback is invoked as SQL statements are being compiled
 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
-** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  At various
+** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
 ** points during the compilation process, as logic is being created
 ** to perform various actions, the authorizer callback is invoked to
-** see if those actions are allowed.  The authorizer callback should
+** see if those actions are allowed.  ^The authorizer callback should
 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
 ** specific action but allow the SQL statement to continue to be
 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
-** rejected with an error.  If the authorizer callback returns
+** rejected with an error.  ^If the authorizer callback returns
 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
 ** the authorizer will fail with an error message.
 **
 ** When the callback returns [SQLITE_OK], that means the operation
-** requested is ok.  When the callback returns [SQLITE_DENY], the
+** requested is ok.  ^When the callback returns [SQLITE_DENY], the
 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
 ** authorizer will fail with an error message explaining that
-** access is denied.  If the authorizer code is [SQLITE_READ]
+** access is denied. 
+**
+** ^The first parameter to the authorizer callback is a copy of the third
+** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
+** to the callback is an integer [SQLITE_COPY | action code] that specifies
+** the particular action to be authorized. ^The third through sixth parameters
+** to the callback are zero-terminated strings that contain additional
+** details about the action to be authorized.
+**
+** ^If the action code is [SQLITE_READ]
 ** and the callback returns [SQLITE_IGNORE] then the
 ** [prepared statement] statement is constructed to substitute
 ** a NULL value in place of the table column that would have
 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
 ** return can be used to deny an untrusted user access to individual
 ** columns of a table.
-**
-** The first parameter to the authorizer callback is a copy of the third
-** parameter to the sqlite3_set_authorizer() interface. The second parameter
-** to the callback is an integer [SQLITE_COPY | action code] that specifies
-** the particular action to be authorized. The third through sixth parameters
-** to the callback are zero-terminated strings that contain additional
-** details about the action to be authorized.
+** ^If the action code is [SQLITE_DELETE] and the callback returns
+** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
+** [truncate optimization] is disabled and all rows are deleted individually.
 **
 ** An authorizer is used when [sqlite3_prepare | preparing]
 ** SQL statements from an untrusted source, to ensure that the SQL statements
@@ -2747,9 +2881,9 @@ SQLITE_API void sqlite3_randomness(int N, void *P);
 ** and limiting database size using the [max_page_count] [PRAGMA]
 ** in addition to using an authorizer.
 **
-** Only a single authorizer can be in place on a database connection
+** ^(Only a single authorizer can be in place on a database connection
 ** at a time.  Each call to sqlite3_set_authorizer overrides the
-** previous call.  Disable the authorizer by installing a NULL callback.
+** previous call.)^  ^Disable the authorizer by installing a NULL callback.
 ** The authorizer is disabled by default.
 **
 ** The authorizer callback must not do anything that will modify
@@ -2757,66 +2891,16 @@ SQLITE_API void sqlite3_randomness(int N, void *P);
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
-** When [sqlite3_prepare_v2()] is used to prepare a statement, the
-** statement might be reprepared during [sqlite3_step()] due to a 
+** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
+** statement might be re-prepared during [sqlite3_step()] due to a 
 ** schema change.  Hence, the application should ensure that the
 ** correct authorizer callback remains in place during the [sqlite3_step()].
 **
-** Note that the authorizer callback is invoked only during
+** ^Note that the authorizer callback is invoked only during
 ** [sqlite3_prepare()] or its variants.  Authorization is not
-** performed during statement evaluation in [sqlite3_step()].
-**
-** INVARIANTS:
-**
-** {H12501} The [sqlite3_set_authorizer(D,...)] interface registers a
-**          authorizer callback with database connection D.
-**
-** {H12502} The authorizer callback is invoked as SQL statements are
-**          being parseed and compiled.
-**
-** {H12503} If the authorizer callback returns any value other than
-**          [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY], then
-**          the application interface call that caused
-**          the authorizer callback to run shall fail with an
-**          [SQLITE_ERROR] error code and an appropriate error message.
-**
-** {H12504} When the authorizer callback returns [SQLITE_OK], the operation
-**          described is processed normally.
-**
-** {H12505} When the authorizer callback returns [SQLITE_DENY], the
-**          application interface call that caused the
-**          authorizer callback to run shall fail
-**          with an [SQLITE_ERROR] error code and an error message
-**          explaining that access is denied.
-**
-** {H12506} If the authorizer code (the 2nd parameter to the authorizer
-**          callback) is [SQLITE_READ] and the authorizer callback returns
-**          [SQLITE_IGNORE], then the prepared statement is constructed to
-**          insert a NULL value in place of the table column that would have
-**          been read if [SQLITE_OK] had been returned.
-**
-** {H12507} If the authorizer code (the 2nd parameter to the authorizer
-**          callback) is anything other than [SQLITE_READ], then
-**          a return of [SQLITE_IGNORE] has the same effect as [SQLITE_DENY].
-**
-** {H12510} The first parameter to the authorizer callback is a copy of
-**          the third parameter to the [sqlite3_set_authorizer()] interface.
-**
-** {H12511} The second parameter to the callback is an integer
-**          [SQLITE_COPY | action code] that specifies the particular action
-**          to be authorized.
-**
-** {H12512} The third through sixth parameters to the callback are
-**          zero-terminated strings that contain
-**          additional details about the action to be authorized.
-**
-** {H12520} Each call to [sqlite3_set_authorizer()] overrides
-**          any previously installed authorizer.
-**
-** {H12521} A NULL authorizer means that no authorization
-**          callback is invoked.
-**
-** {H12522} The default authorizer is NULL.
+** performed during statement evaluation in [sqlite3_step()], unless
+** as stated in the previous paragraph, sqlite3_step() invokes
+** sqlite3_prepare_v2() to reprepare a statement after a schema change.
 */
 SQLITE_API int sqlite3_set_authorizer(
   sqlite3*,
@@ -2825,19 +2909,22 @@ SQLITE_API int sqlite3_set_authorizer(
 );
 
 /*
-** CAPI3REF: Authorizer Return Codes {H12590} <H12500>
+** CAPI3REF: Authorizer Return Codes
 **
 ** The [sqlite3_set_authorizer | authorizer callback function] must
 ** return either [SQLITE_OK] or one of these two constants in order
 ** to signal SQLite whether or not the action is permitted.  See the
 ** [sqlite3_set_authorizer | authorizer documentation] for additional
 ** information.
+**
+** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
+** from the [sqlite3_vtab_on_conflict()] interface.
 */
 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
 
 /*
-** CAPI3REF: Authorizer Action Codes {H12550} <H12500>
+** CAPI3REF: Authorizer Action Codes
 **
 ** The [sqlite3_set_authorizer()] interface registers a callback function
 ** that is invoked to authorize certain SQL statement actions.  The
@@ -2848,34 +2935,12 @@ SQLITE_API int sqlite3_set_authorizer(
 ** These action code values signify what kind of operation is to be
 ** authorized.  The 3rd and 4th parameters to the authorization
 ** callback function will be parameters or NULL depending on which of these
-** codes is used as the second parameter.  The 5th parameter to the
+** codes is used as the second parameter.  ^(The 5th parameter to the
 ** authorizer callback is the name of the database ("main", "temp",
-** etc.) if applicable.  The 6th parameter to the authorizer callback
+** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
 ** is the name of the inner-most trigger or view that is responsible for
 ** the access attempt or NULL if this access attempt is directly from
 ** top-level SQL code.
-**
-** INVARIANTS:
-**
-** {H12551} The second parameter to an
-**          [sqlite3_set_authorizer | authorizer callback] shall be an integer
-**          [SQLITE_COPY | authorizer code] that specifies what action
-**          is being authorized.
-**
-** {H12552} The 3rd and 4th parameters to the
-**          [sqlite3_set_authorizer | authorization callback]
-**          shall be parameters or NULL depending on which
-**          [SQLITE_COPY | authorizer code] is used as the second parameter.
-**
-** {H12553} The 5th parameter to the
-**          [sqlite3_set_authorizer | authorizer callback] shall be the name
-**          of the database (example: "main", "temp", etc.) if applicable.
-**
-** {H12554} The 6th parameter to the
-**          [sqlite3_set_authorizer | authorizer callback] shall be the name
-**          of the inner-most trigger or view that is responsible for
-**          the access attempt or NULL if this access attempt is directly from
-**          top-level SQL code.
 */
 /******************************************* 3rd ************ 4th ***********/
 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
@@ -2913,132 +2978,83 @@ SQLITE_API int sqlite3_set_authorizer(
 #define SQLITE_COPY                  0   /* No longer used */
 
 /*
-** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400>
-** EXPERIMENTAL
+** CAPI3REF: Tracing And Profiling Functions
 **
 ** These routines register callback functions that can be used for
 ** tracing and profiling the execution of SQL statements.
 **
-** The callback function registered by sqlite3_trace() is invoked at
+** ^The callback function registered by sqlite3_trace() is invoked at
 ** various times when an SQL statement is being run by [sqlite3_step()].
-** The callback returns a UTF-8 rendering of the SQL statement text
-** as the statement first begins executing.  Additional callbacks occur
+** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
+** SQL statement text as the statement first begins executing.
+** ^(Additional sqlite3_trace() callbacks might occur
 ** as each triggered subprogram is entered.  The callbacks for triggers
-** contain a UTF-8 SQL comment that identifies the trigger.
+** contain a UTF-8 SQL comment that identifies the trigger.)^
 **
-** The callback function registered by sqlite3_profile() is invoked
-** as each SQL statement finishes.  The profile callback contains
+** ^The callback function registered by sqlite3_profile() is invoked
+** as each SQL statement finishes.  ^The profile callback contains
 ** the original statement text and an estimate of wall-clock time
-** of how long that statement took to run.
-**
-** INVARIANTS:
-**
-** {H12281} The callback function registered by [sqlite3_trace()] 
-**          shall be invoked
-**          whenever an SQL statement first begins to execute and
-**          whenever a trigger subprogram first begins to run.
-**
-** {H12282} Each call to [sqlite3_trace()] shall override the previously
-**          registered trace callback.
-**
-** {H12283} A NULL trace callback shall disable tracing.
-**
-** {H12284} The first argument to the trace callback shall be a copy of
-**          the pointer which was the 3rd argument to [sqlite3_trace()].
-**
-** {H12285} The second argument to the trace callback is a
-**          zero-terminated UTF-8 string containing the original text
-**          of the SQL statement as it was passed into [sqlite3_prepare_v2()]
-**          or the equivalent, or an SQL comment indicating the beginning
-**          of a trigger subprogram.
-**
-** {H12287} The callback function registered by [sqlite3_profile()] is invoked
-**          as each SQL statement finishes.
-**
-** {H12288} The first parameter to the profile callback is a copy of
-**          the 3rd parameter to [sqlite3_profile()].
-**
-** {H12289} The second parameter to the profile callback is a
-**          zero-terminated UTF-8 string that contains the complete text of
-**          the SQL statement as it was processed by [sqlite3_prepare_v2()]
-**          or the equivalent.
-**
-** {H12290} The third parameter to the profile callback is an estimate
-**          of the number of nanoseconds of wall-clock time required to
-**          run the SQL statement from start to finish.
+** of how long that statement took to run.  ^The profile callback
+** time is in units of nanoseconds, however the current implementation
+** is only capable of millisecond resolution so the six least significant
+** digits in the time are meaningless.  Future versions of SQLite
+** might provide greater resolution on the profiler callback.  The
+** sqlite3_profile() function is considered experimental and is
+** subject to change in future versions of SQLite.
 */
-SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
+SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
 
 /*
-** CAPI3REF: Query Progress Callbacks {H12910} <S60400>
+** CAPI3REF: Query Progress Callbacks
 **
-** This routine configures a callback function - the
-** progress callback - that is invoked periodically during long
-** running calls to [sqlite3_exec()], [sqlite3_step()] and
-** [sqlite3_get_table()].  An example use for this
+** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
+** function X to be invoked periodically during long running calls to
+** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
+** database connection D.  An example use for this
 ** interface is to keep a GUI updated during a large query.
 **
-** If the progress callback returns non-zero, the operation is
+** ^The parameter P is passed through as the only parameter to the 
+** callback function X.  ^The parameter N is the number of 
+** [virtual machine instructions] that are evaluated between successive
+** invocations of the callback X.
+**
+** ^Only a single progress handler may be defined at one time per
+** [database connection]; setting a new progress handler cancels the
+** old one.  ^Setting parameter X to NULL disables the progress handler.
+** ^The progress handler is also disabled by setting N to a value less
+** than 1.
+**
+** ^If the progress callback returns non-zero, the operation is
 ** interrupted.  This feature can be used to implement a
 ** "Cancel" button on a GUI progress dialog box.
 **
-** The progress handler must not do anything that will modify
+** The progress handler callback must not do anything that will modify
 ** the database connection that invoked the progress handler.
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
-** INVARIANTS:
-**
-** {H12911} The callback function registered by sqlite3_progress_handler()
-**          is invoked periodically during long running calls to
-**          [sqlite3_step()].
-**
-** {H12912} The progress callback is invoked once for every N virtual
-**          machine opcodes, where N is the second argument to
-**          the [sqlite3_progress_handler()] call that registered
-**          the callback.  If N is less than 1, sqlite3_progress_handler()
-**          acts as if a NULL progress handler had been specified.
-**
-** {H12913} The progress callback itself is identified by the third
-**          argument to sqlite3_progress_handler().
-**
-** {H12914} The fourth argument to sqlite3_progress_handler() is a
-**          void pointer passed to the progress callback
-**          function each time it is invoked.
-**
-** {H12915} If a call to [sqlite3_step()] results in fewer than N opcodes
-**          being executed, then the progress callback is never invoked.
-**
-** {H12916} Every call to [sqlite3_progress_handler()]
-**          overwrites any previously registered progress handler.
-**
-** {H12917} If the progress handler callback is NULL then no progress
-**          handler is invoked.
-**
-** {H12918} If the progress callback returns a result other than 0, then
-**          the behavior is a if [sqlite3_interrupt()] had been called.
-**          <S30500>
 */
 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 
 /*
-** CAPI3REF: Opening A New Database Connection {H12700} <S40200>
+** CAPI3REF: Opening A New Database Connection
 **
-** These routines open an SQLite database file whose name is given by the
-** filename argument. The filename argument is interpreted as UTF-8 for
+** ^These routines open an SQLite database file as specified by the 
+** filename argument. ^The filename argument is interpreted as UTF-8 for
 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
-** order for sqlite3_open16(). A [database connection] handle is usually
+** order for sqlite3_open16(). ^(A [database connection] handle is usually
 ** returned in *ppDb, even if an error occurs.  The only exception is that
 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
-** object. If the database is opened (and/or created) successfully, then
-** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.  The
+** object.)^ ^(If the database is opened (and/or created) successfully, then
+** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
-** an English language description of the error.
+** an English language description of the error following a failure of any
+** of the sqlite3_open() routines.
 **
-** The default encoding for the database will be UTF-8 if
+** ^The default encoding for the database will be UTF-8 if
 ** sqlite3_open() or sqlite3_open_v2() is called and
 ** UTF-16 in the native byte order if sqlite3_open16() is used.
 **
@@ -3048,54 +3064,169 @@ SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 **
 ** The sqlite3_open_v2() interface works like sqlite3_open()
 ** except that it accepts two additional parameters for additional control
-** over the new database connection.  The flags parameter can take one of
+** over the new database connection.  ^(The flags parameter to
+** sqlite3_open_v2() can take one of
 ** the following three values, optionally combined with the 
-** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags:
+** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
+** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
 **
 ** <dl>
-** <dt>[SQLITE_OPEN_READONLY]</dt>
+** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
 ** <dd>The database is opened in read-only mode.  If the database does not
-** already exist, an error is returned.</dd>
+** already exist, an error is returned.</dd>)^
 **
-** <dt>[SQLITE_OPEN_READWRITE]</dt>
+** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
 ** <dd>The database is opened for reading and writing if possible, or reading
 ** only if the file is write protected by the operating system.  In either
-** case the database must already exist, otherwise an error is returned.</dd>
+** case the database must already exist, otherwise an error is returned.</dd>)^
 **
-** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
-** <dd>The database is opened for reading and writing, and is creates it if
+** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
+** <dd>The database is opened for reading and writing, and is created if
 ** it does not already exist. This is the behavior that is always used for
-** sqlite3_open() and sqlite3_open16().</dd>
+** sqlite3_open() and sqlite3_open16().</dd>)^
 ** </dl>
 **
 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
-** combinations shown above or one of the combinations shown above combined
-** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags,
+** combinations shown above optionally combined with other
+** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
 ** then the behavior is undefined.
 **
-** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
+** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
 ** opens in the multi-thread [threading mode] as long as the single-thread
-** mode has not been set at compile-time or start-time.  If the
+** mode has not been set at compile-time or start-time.  ^If the
 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
 ** in the serialized [threading mode] unless single-thread was
 ** previously selected at compile-time or start-time.
+** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
+** eligible to use [shared cache mode], regardless of whether or not shared
+** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
+** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
+** participate in [shared cache mode] even if it is enabled.
 **
-** If the filename is ":memory:", then a private, temporary in-memory database
-** is created for the connection.  This in-memory database will vanish when
+** ^The fourth parameter to sqlite3_open_v2() is the name of the
+** [sqlite3_vfs] object that defines the operating system interface that
+** the new database connection should use.  ^If the fourth parameter is
+** a NULL pointer then the default [sqlite3_vfs] object is used.
+**
+** ^If the filename is ":memory:", then a private, temporary in-memory database
+** is created for the connection.  ^This in-memory database will vanish when
 ** the database connection is closed.  Future versions of SQLite might
 ** make use of additional special filenames that begin with the ":" character.
 ** It is recommended that when a database filename actually does begin with
 ** a ":" character you should prefix the filename with a pathname such as
 ** "./" to avoid ambiguity.
 **
-** If the filename is an empty string, then a private, temporary
-** on-disk database will be created.  This private database will be
+** ^If the filename is an empty string, then a private, temporary
+** on-disk database will be created.  ^This private database will be
 ** automatically deleted as soon as the database connection is closed.
 **
-** The fourth parameter to sqlite3_open_v2() is the name of the
-** [sqlite3_vfs] object that defines the operating system interface that
-** the new database connection should use.  If the fourth parameter is
-** a NULL pointer then the default [sqlite3_vfs] object is used.
+** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
+**
+** ^If [URI filename] interpretation is enabled, and the filename argument
+** begins with "file:", then the filename is interpreted as a URI. ^URI
+** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
+** set in the fourth argument to sqlite3_open_v2(), or if it has
+** been enabled globally using the [SQLITE_CONFIG_URI] option with the
+** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
+** As of SQLite version 3.7.7, URI filename interpretation is turned off
+** by default, but future releases of SQLite might enable URI filename
+** interpretation by default.  See "[URI filenames]" for additional
+** information.
+**
+** URI filenames are parsed according to RFC 3986. ^If the URI contains an
+** authority, then it must be either an empty string or the string 
+** "localhost". ^If the authority is not an empty string or "localhost", an 
+** error is returned to the caller. ^The fragment component of a URI, if 
+** present, is ignored.
+**
+** ^SQLite uses the path component of the URI as the name of the disk file
+** which contains the database. ^If the path begins with a '/' character, 
+** then it is interpreted as an absolute path. ^If the path does not begin 
+** with a '/' (meaning that the authority section is omitted from the URI)
+** then the path is interpreted as a relative path. 
+** ^On windows, the first component of an absolute path 
+** is a drive specification (e.g. "C:").
+**
+** [[core URI query parameters]]
+** The query component of a URI may contain parameters that are interpreted
+** either by SQLite itself, or by a [VFS | custom VFS implementation].
+** SQLite interprets the following three query parameters:
+**
+** <ul>
+**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
+**     a VFS object that provides the operating system interface that should
+**     be used to access the database file on disk. ^If this option is set to
+**     an empty string the default VFS object is used. ^Specifying an unknown
+**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
+**     present, then the VFS specified by the option takes precedence over
+**     the value passed as the fourth parameter to sqlite3_open_v2().
+**
+**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
+**     "rwc", or "memory". Attempting to set it to any other value is
+**     an error)^. 
+**     ^If "ro" is specified, then the database is opened for read-only 
+**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 
+**     third argument to sqlite3_prepare_v2(). ^If the mode option is set to 
+**     "rw", then the database is opened for read-write (but not create) 
+**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 
+**     been set. ^Value "rwc" is equivalent to setting both 
+**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
+**     set to "memory" then a pure [in-memory database] that never reads
+**     or writes from disk is used. ^It is an error to specify a value for
+**     the mode parameter that is less restrictive than that specified by
+**     the flags passed in the third parameter to sqlite3_open_v2().
+**
+**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
+**     "private". ^Setting it to "shared" is equivalent to setting the
+**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
+**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is 
+**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
+**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
+**     a URI filename, its value overrides any behaviour requested by setting
+**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
+** </ul>
+**
+** ^Specifying an unknown parameter in the query component of a URI is not an
+** error.  Future versions of SQLite might understand additional query
+** parameters.  See "[query parameters with special meaning to SQLite]" for
+** additional information.
+**
+** [[URI filename examples]] <h3>URI filename examples</h3>
+**
+** <table border="1" align=center cellpadding=5>
+** <tr><th> URI filenames <th> Results
+** <tr><td> file:data.db <td> 
+**          Open the file "data.db" in the current directory.
+** <tr><td> file:/home/fred/data.db<br>
+**          file:///home/fred/data.db <br> 
+**          file://localhost/home/fred/data.db <br> <td> 
+**          Open the database file "/home/fred/data.db".
+** <tr><td> file://darkstar/home/fred/data.db <td> 
+**          An error. "darkstar" is not a recognized authority.
+** <tr><td style="white-space:nowrap"> 
+**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
+**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
+**          C:. Note that the %20 escaping in this example is not strictly 
+**          necessary - space characters can be used literally
+**          in URI filenames.
+** <tr><td> file:data.db?mode=ro&cache=private <td> 
+**          Open file "data.db" in the current directory for read-only access.
+**          Regardless of whether or not shared-cache mode is enabled by
+**          default, use a private cache.
+** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
+**          Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
+** <tr><td> file:data.db?mode=readonly <td> 
+**          An error. "readonly" is not a valid option for the "mode" parameter.
+** </table>
+**
+** ^URI hexadecimal escape sequences (%HH) are supported within the path and
+** query components of a URI. A hexadecimal escape sequence consists of a
+** percent sign - "%" - followed by exactly two hexadecimal digits 
+** specifying an octet value. ^Before the path or query components of a
+** URI filename are interpreted, they are encoded using UTF-8 and all 
+** hexadecimal escape sequences replaced by a single byte containing the
+** corresponding octet. If this process generates an invalid UTF-8 encoding,
+** the results are undefined.
 **
 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
@@ -3103,72 +3234,11 @@ SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 ** characters must be converted to UTF-8 prior to passing them into
 ** sqlite3_open() or sqlite3_open_v2().
 **
-** INVARIANTS:
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
+** features that require the use of temporary files may fail.
 **
-** {H12701} The [sqlite3_open()], [sqlite3_open16()], and
-**          [sqlite3_open_v2()] interfaces create a new
-**          [database connection] associated with
-**          the database file given in their first parameter.
-**
-** {H12702} The filename argument is interpreted as UTF-8
-**          for [sqlite3_open()] and [sqlite3_open_v2()] and as UTF-16
-**          in the native byte order for [sqlite3_open16()].
-**
-** {H12703} A successful invocation of [sqlite3_open()], [sqlite3_open16()],
-**          or [sqlite3_open_v2()] writes a pointer to a new
-**          [database connection] into *ppDb.
-**
-** {H12704} The [sqlite3_open()], [sqlite3_open16()], and
-**          [sqlite3_open_v2()] interfaces return [SQLITE_OK] upon success,
-**          or an appropriate [error code] on failure.
-**
-** {H12706} The default text encoding for a new database created using
-**          [sqlite3_open()] or [sqlite3_open_v2()] will be UTF-8.
-**
-** {H12707} The default text encoding for a new database created using
-**          [sqlite3_open16()] will be UTF-16.
-**
-** {H12709} The [sqlite3_open(F,D)] interface is equivalent to
-**          [sqlite3_open_v2(F,D,G,0)] where the G parameter is
-**          [SQLITE_OPEN_READWRITE]|[SQLITE_OPEN_CREATE].
-**
-** {H12711} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
-**          bit value [SQLITE_OPEN_READONLY] then the database is opened
-**          for reading only.
-**
-** {H12712} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
-**          bit value [SQLITE_OPEN_READWRITE] then the database is opened
-**          reading and writing if possible, or for reading only if the
-**          file is write protected by the operating system.
-**
-** {H12713} If the G parameter to [sqlite3_open_v2(F,D,G,V)] omits the
-**          bit value [SQLITE_OPEN_CREATE] and the database does not
-**          previously exist, an error is returned.
-**
-** {H12714} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
-**          bit value [SQLITE_OPEN_CREATE] and the database does not
-**          previously exist, then an attempt is made to create and
-**          initialize the database.
-**
-** {H12717} If the filename argument to [sqlite3_open()], [sqlite3_open16()],
-**          or [sqlite3_open_v2()] is ":memory:", then an private,
-**          ephemeral, in-memory database is created for the connection.
-**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
-**          in sqlite3_open_v2()?</todo>
-**
-** {H12719} If the filename is NULL or an empty string, then a private,
-**          ephemeral on-disk database will be created.
-**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
-**          in sqlite3_open_v2()?</todo>
-**
-** {H12721} The [database connection] created by [sqlite3_open_v2(F,D,G,V)]
-**          will use the [sqlite3_vfs] object identified by the V parameter,
-**          or the default [sqlite3_vfs] object if V is a NULL pointer.
-**
-** {H12723} Two [database connections] will share a common cache if both were
-**          opened with the same VFS while [shared cache mode] was enabled and
-**          if both filenames compare equal using memcmp() after having been
-**          processed by the [sqlite3_vfs | xFullPathname] method of the VFS.
+** See also: [sqlite3_temp_directory]
 */
 SQLITE_API int sqlite3_open(
   const char *filename,   /* Database filename (UTF-8) */
@@ -3186,23 +3256,67 @@ SQLITE_API int sqlite3_open_v2(
 );
 
 /*
-** CAPI3REF: Error Codes And Messages {H12800} <S60200>
+** CAPI3REF: Obtain Values For URI Parameters
 **
-** The sqlite3_errcode() interface returns the numeric [result code] or
+** These are utility routines, useful to VFS implementations, that check
+** to see if a database file was a URI that contained a specific query 
+** parameter, and if so obtains the value of that query parameter.
+**
+** If F is the database filename pointer passed into the xOpen() method of 
+** a VFS implementation when the flags parameter to xOpen() has one or 
+** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
+** P is the name of the query parameter, then
+** sqlite3_uri_parameter(F,P) returns the value of the P
+** parameter if it exists or a NULL pointer if P does not appear as a 
+** query parameter on F.  If P is a query parameter of F
+** has no explicit value, then sqlite3_uri_parameter(F,P) returns
+** a pointer to an empty string.
+**
+** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
+** parameter and returns true (1) or false (0) according to the value
+** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
+** value of query parameter P is one of "yes", "true", or "on" in any
+** case or if the value begins with a non-zero number.  The 
+** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
+** query parameter P is one of "no", "false", or "off" in any case or
+** if the value begins with a numeric zero.  If P is not a query
+** parameter on F or if the value of P is does not match any of the
+** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
+**
+** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
+** 64-bit signed integer and returns that integer, or D if P does not
+** exist.  If the value of P is something other than an integer, then
+** zero is returned.
+** 
+** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
+** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
+** is not a database file pathname pointer that SQLite passed into the xOpen
+** VFS method, then the behavior of this routine is undefined and probably
+** undesirable.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
+SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
+
+
+/*
+** CAPI3REF: Error Codes And Messages
+**
+** ^The sqlite3_errcode() interface returns the numeric [result code] or
 ** [extended result code] for the most recent failed sqlite3_* API call
 ** associated with a [database connection]. If a prior API call failed
 ** but the most recent API call succeeded, the return value from
-** sqlite3_errcode() is undefined.  The sqlite3_extended_errcode()
+** sqlite3_errcode() is undefined.  ^The sqlite3_extended_errcode()
 ** interface is the same except that it always returns the 
 ** [extended result code] even when extended result codes are
 ** disabled.
 **
-** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
+** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
-** Memory to hold the error message string is managed internally.
+** ^(Memory to hold the error message string is managed internally.
 ** The application does not need to worry about freeing the result.
 ** However, the error string might be overwritten or deallocated by
-** subsequent calls to other SQLite interface functions.
+** subsequent calls to other SQLite interface functions.)^
 **
 ** When the serialized [threading mode] is in use, it might be the
 ** case that a second error occurs on a separate thread in between
@@ -3217,37 +3331,6 @@ SQLITE_API int sqlite3_open_v2(
 ** If an interface fails with SQLITE_MISUSE, that means the interface
 ** was invoked incorrectly by the application.  In that case, the
 ** error code and message may or may not be set.
-**
-** INVARIANTS:
-**
-** {H12801} The [sqlite3_errcode(D)] interface returns the numeric
-**          [result code] or [extended result code] for the most recently
-**          failed interface call associated with the [database connection] D.
-**
-** {H12802} The [sqlite3_extended_errcode(D)] interface returns the numeric
-**          [extended result code] for the most recently
-**          failed interface call associated with the [database connection] D.
-**
-** {H12803} The [sqlite3_errmsg(D)] and [sqlite3_errmsg16(D)]
-**          interfaces return English-language text that describes
-**          the error in the mostly recently failed interface call,
-**          encoded as either UTF-8 or UTF-16 respectively.
-**
-** {H12807} The strings returned by [sqlite3_errmsg()] and [sqlite3_errmsg16()]
-**          are valid until the next SQLite interface call.
-**
-** {H12808} Calls to API routines that do not return an error code
-**          (example: [sqlite3_data_count()]) do not
-**          change the error code or message returned by
-**          [sqlite3_errcode()], [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], or [sqlite3_errmsg16()].
-**
-** {H12809} Interfaces that are not associated with a specific
-**          [database connection] (examples:
-**          [sqlite3_mprintf()] or [sqlite3_enable_shared_cache()]
-**          do not change the values returned by
-**          [sqlite3_errcode()], [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], or [sqlite3_errmsg16()].
 */
 SQLITE_API int sqlite3_errcode(sqlite3 *db);
 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
@@ -3255,7 +3338,7 @@ SQLITE_API const char *sqlite3_errmsg(sqlite3*);
 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
 
 /*
-** CAPI3REF: SQL Statement Object {H13000} <H13010>
+** CAPI3REF: SQL Statement Object
 ** KEYWORDS: {prepared statement} {prepared statements}
 **
 ** An instance of this object represents a single SQL statement.
@@ -3281,26 +3364,33 @@ SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
 typedef struct sqlite3_stmt sqlite3_stmt;
 
 /*
-** CAPI3REF: Run-time Limits {H12760} <S20600>
+** CAPI3REF: Run-time Limits
 **
-** This interface allows the size of various constructs to be limited
+** ^(This interface allows the size of various constructs to be limited
 ** on a connection by connection basis.  The first parameter is the
 ** [database connection] whose limit is to be set or queried.  The
 ** second parameter is one of the [limit categories] that define a
 ** class of constructs to be size limited.  The third parameter is the
-** new limit for that construct.  The function returns the old limit.
+** new limit for that construct.)^
 **
-** If the new limit is a negative number, the limit is unchanged.
-** For the limit category of SQLITE_LIMIT_XYZ there is a hard upper
-** bound set by a compile-time C preprocessor macro named SQLITE_MAX_XYZ.
-** (The "_LIMIT_" in the name is changed to "_MAX_".)
-** Attempts to increase a limit above its hard upper bound are
-** silently truncated to the hard upper limit.
+** ^If the new limit is a negative number, the limit is unchanged.
+** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 
+** [limits | hard upper bound]
+** set at compile-time by a C preprocessor macro called
+** [limits | SQLITE_MAX_<i>NAME</i>].
+** (The "_LIMIT_" in the name is changed to "_MAX_".))^
+** ^Attempts to increase a limit above its hard upper bound are
+** silently truncated to the hard upper bound.
 **
-** Run time limits are intended for use in applications that manage
+** ^Regardless of whether or not the limit was changed, the 
+** [sqlite3_limit()] interface returns the prior value of the limit.
+** ^Hence, to find the current value of a limit without changing it,
+** simply invoke this interface with the third parameter set to -1.
+**
+** Run-time limits are intended for use in applications that manage
 ** both their own internal database and also databases that are controlled
 ** by untrusted external sources.  An example application might be a
-** webbrowser that has its own databases for storing history and
+** web browser that has its own databases for storing history and
 ** separate databases controlled by JavaScript applications downloaded
 ** off the Internet.  The internal databases can be given the
 ** large, default limits.  Databases managed by external sources can
@@ -3311,66 +3401,59 @@ typedef struct sqlite3_stmt sqlite3_stmt;
 ** [max_page_count] [PRAGMA].
 **
 ** New run-time limit categories may be added in future releases.
-**
-** INVARIANTS:
-**
-** {H12762} A successful call to [sqlite3_limit(D,C,V)] where V is
-**          positive changes the limit on the size of construct C in the
-**          [database connection] D to the lesser of V and the hard upper
-**          bound on the size of C that is set at compile-time.
-**
-** {H12766} A successful call to [sqlite3_limit(D,C,V)] where V is negative
-**          leaves the state of the [database connection] D unchanged.
-**
-** {H12769} A successful call to [sqlite3_limit(D,C,V)] returns the
-**          value of the limit on the size of construct C in the
-**          [database connection] D as it was prior to the call.
 */
 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
 
 /*
-** CAPI3REF: Run-Time Limit Categories {H12790} <H12760>
-** KEYWORDS: {limit category} {limit categories}
+** CAPI3REF: Run-Time Limit Categories
+** KEYWORDS: {limit category} {*limit categories}
 **
-** These constants define various aspects of a [database connection]
-** that can be limited in size by calls to [sqlite3_limit()].
-** The meanings of the various limits are as follows:
+** These constants define various performance limits
+** that can be lowered at run-time using [sqlite3_limit()].
+** The synopsis of the meanings of the various limits is shown below.
+** Additional information is available at [limits | Limits in SQLite].
 **
 ** <dl>
-** <dt>SQLITE_LIMIT_LENGTH</dt>
-** <dd>The maximum size of any string or BLOB or table row.<dd>
+** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
+** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
 **
-** <dt>SQLITE_LIMIT_SQL_LENGTH</dt>
-** <dd>The maximum length of an SQL statement.</dd>
+** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
+** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
 **
-** <dt>SQLITE_LIMIT_COLUMN</dt>
+** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
 ** <dd>The maximum number of columns in a table definition or in the
-** result set of a SELECT or the maximum number of columns in an index
-** or in an ORDER BY or GROUP BY clause.</dd>
+** result set of a [SELECT] or the maximum number of columns in an index
+** or in an ORDER BY or GROUP BY clause.</dd>)^
 **
-** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
-** <dd>The maximum depth of the parse tree on any expression.</dd>
+** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
+** <dd>The maximum depth of the parse tree on any expression.</dd>)^
 **
-** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
-** <dd>The maximum number of terms in a compound SELECT statement.</dd>
+** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
+** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
 **
-** <dt>SQLITE_LIMIT_VDBE_OP</dt>
+** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
 ** <dd>The maximum number of instructions in a virtual machine program
-** used to implement an SQL statement.</dd>
+** used to implement an SQL statement.  This limit is not currently
+** enforced, though that might be added in some future release of
+** SQLite.</dd>)^
 **
-** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
-** <dd>The maximum number of arguments on a function.</dd>
+** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
+** <dd>The maximum number of arguments on a function.</dd>)^
 **
-** <dt>SQLITE_LIMIT_ATTACHED</dt>
-** <dd>The maximum number of attached databases.</dd>
+** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
+** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
 **
-** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
-** <dd>The maximum length of the pattern argument to the LIKE or
-** GLOB operators.</dd>
+** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
+** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
+** <dd>The maximum length of the pattern argument to the [LIKE] or
+** [GLOB] operators.</dd>)^
 **
-** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
-** <dd>The maximum number of variables in an SQL statement that can
-** be bound.</dd>
+** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
+** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
+** <dd>The maximum index number of any [parameter] in an SQL statement.)^
+**
+** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
+** <dd>The maximum depth of recursion for triggers.</dd>)^
 ** </dl>
 */
 #define SQLITE_LIMIT_LENGTH                    0
@@ -3383,111 +3466,88 @@ SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
 #define SQLITE_LIMIT_ATTACHED                  7
 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
+#define SQLITE_LIMIT_TRIGGER_DEPTH            10
 
 /*
-** CAPI3REF: Compiling An SQL Statement {H13010} <S10000>
+** CAPI3REF: Compiling An SQL Statement
 ** KEYWORDS: {SQL statement compiler}
 **
 ** To execute an SQL query, it must first be compiled into a byte-code
 ** program using one of these routines.
 **
 ** The first argument, "db", is a [database connection] obtained from a
-** prior call to [sqlite3_open()], [sqlite3_open_v2()] or [sqlite3_open16()].
+** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
+** [sqlite3_open16()].  The database connection must not have been closed.
 **
 ** The second argument, "zSql", is the statement to be compiled, encoded
 ** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
 ** use UTF-16.
 **
-** If the nByte argument is less than zero, then zSql is read up to the
-** first zero terminator. If nByte is non-negative, then it is the maximum
-** number of  bytes read from zSql.  When nByte is non-negative, the
+** ^If the nByte argument is less than zero, then zSql is read up to the
+** first zero terminator. ^If nByte is non-negative, then it is the maximum
+** number of  bytes read from zSql.  ^When nByte is non-negative, the
 ** zSql string ends at either the first '\000' or '\u0000' character or
 ** the nByte-th byte, whichever comes first. If the caller knows
 ** that the supplied string is nul-terminated, then there is a small
 ** performance advantage to be gained by passing an nByte parameter that
 ** is equal to the number of bytes in the input string <i>including</i>
-** the nul-terminator bytes.
+** the nul-terminator bytes as this saves SQLite from having to
+** make a copy of the input string.
 **
-** *pzTail is made to point to the first byte past the end of the
-** first SQL statement in zSql.  These routines only compile the first
-** statement in zSql, so *pzTail is left pointing to what remains
-** uncompiled.
+** ^If pzTail is not NULL then *pzTail is made to point to the first byte
+** past the end of the first SQL statement in zSql.  These routines only
+** compile the first statement in zSql, so *pzTail is left pointing to
+** what remains uncompiled.
 **
-** *ppStmt is left pointing to a compiled [prepared statement] that can be
-** executed using [sqlite3_step()].  If there is an error, *ppStmt is set
-** to NULL.  If the input text contains no SQL (if the input is an empty
+** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
+** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
+** to NULL.  ^If the input text contains no SQL (if the input is an empty
 ** string or a comment) then *ppStmt is set to NULL.
-** {A13018} The calling procedure is responsible for deleting the compiled
+** The calling procedure is responsible for deleting the compiled
 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
+** ppStmt may not be NULL.
 **
-** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned.
+** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
+** otherwise an [error code] is returned.
 **
 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
 ** recommended for all new programs. The two older interfaces are retained
 ** for backwards compatibility, but their use is discouraged.
-** In the "v2" interfaces, the prepared statement
+** ^In the "v2" interfaces, the prepared statement
 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
 ** original SQL text. This causes the [sqlite3_step()] interface to
-** behave a differently in two ways:
+** behave differently in three ways:
 **
 ** <ol>
 ** <li>
-** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
+** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
-** statement and try to run it again.  If the schema has changed in
-** a way that makes the statement no longer valid, [sqlite3_step()] will still
-** return [SQLITE_SCHEMA].  But unlike the legacy behavior, [SQLITE_SCHEMA] is
-** now a fatal error.  Calling [sqlite3_prepare_v2()] again will not make the
-** error go away.  Note: use [sqlite3_errmsg()] to find the text
-** of the parsing error that results in an [SQLITE_SCHEMA] return.
+** statement and try to run it again.
 ** </li>
 **
 ** <li>
-** When an error occurs, [sqlite3_step()] will return one of the detailed
-** [error codes] or [extended error codes].  The legacy behavior was that
+** ^When an error occurs, [sqlite3_step()] will return one of the detailed
+** [error codes] or [extended error codes].  ^The legacy behavior was that
 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
-** and you would have to make a second call to [sqlite3_reset()] in order
-** to find the underlying cause of the problem. With the "v2" prepare
+** and the application would have to make a second call to [sqlite3_reset()]
+** in order to find the underlying cause of the problem. With the "v2" prepare
 ** interfaces, the underlying reason for the error is returned immediately.
 ** </li>
+**
+** <li>
+** ^If the specific value bound to [parameter | host parameter] in the 
+** WHERE clause might influence the choice of query plan for a statement,
+** then the statement will be automatically recompiled, as if there had been 
+** a schema change, on the first  [sqlite3_step()] call following any change
+** to the [sqlite3_bind_text | bindings] of that [parameter]. 
+** ^The specific value of WHERE-clause [parameter] might influence the 
+** choice of query plan if the parameter is the left-hand side of a [LIKE]
+** or [GLOB] operator or if the parameter is compared to an indexed column
+** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
+** the 
+** </li>
 ** </ol>
-**
-** INVARIANTS:
-**
-** {H13011} The [sqlite3_prepare(db,zSql,...)] and
-**          [sqlite3_prepare_v2(db,zSql,...)] interfaces interpret the
-**          text in their zSql parameter as UTF-8.
-**
-** {H13012} The [sqlite3_prepare16(db,zSql,...)] and
-**          [sqlite3_prepare16_v2(db,zSql,...)] interfaces interpret the
-**          text in their zSql parameter as UTF-16 in the native byte order.
-**
-** {H13013} If the nByte argument to [sqlite3_prepare_v2(db,zSql,nByte,...)]
-**          and its variants is less than zero, the SQL text is
-**          read from zSql is read up to the first zero terminator.
-**
-** {H13014} If the nByte argument to [sqlite3_prepare_v2(db,zSql,nByte,...)]
-**          and its variants is non-negative, then at most nBytes bytes of
-**          SQL text is read from zSql.
-**
-** {H13015} In [sqlite3_prepare_v2(db,zSql,N,P,pzTail)] and its variants
-**          if the zSql input text contains more than one SQL statement
-**          and pzTail is not NULL, then *pzTail is made to point to the
-**          first byte past the end of the first SQL statement in zSql.
-**          <todo>What does *pzTail point to if there is one statement?</todo>
-**
-** {H13016} A successful call to [sqlite3_prepare_v2(db,zSql,N,ppStmt,...)]
-**          or one of its variants writes into *ppStmt a pointer to a new
-**          [prepared statement] or a pointer to NULL if zSql contains
-**          nothing other than whitespace or comments.
-**
-** {H13019} The [sqlite3_prepare_v2()] interface and its variants return
-**          [SQLITE_OK] or an appropriate [error code] upon failure.
-**
-** {H13021} Before [sqlite3_prepare(db,zSql,nByte,ppStmt,pzTail)] or its
-**          variants returns an error (any value other than [SQLITE_OK]),
-**          they first set *ppStmt to NULL.
 */
 SQLITE_API int sqlite3_prepare(
   sqlite3 *db,            /* Database handle */
@@ -3519,36 +3579,71 @@ SQLITE_API int sqlite3_prepare16_v2(
 );
 
 /*
-** CAPI3REF: Retrieving Statement SQL {H13100} <H13000>
+** CAPI3REF: Retrieving Statement SQL
 **
-** This interface can be used to retrieve a saved copy of the original
+** ^This interface can be used to retrieve a saved copy of the original
 ** SQL text used to create a [prepared statement] if that statement was
 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
-**
-** INVARIANTS:
-**
-** {H13101} If the [prepared statement] passed as the argument to
-**          [sqlite3_sql()] was compiled using either [sqlite3_prepare_v2()] or
-**          [sqlite3_prepare16_v2()], then [sqlite3_sql()] returns
-**          a pointer to a zero-terminated string containing a UTF-8 rendering
-**          of the original SQL statement.
-**
-** {H13102} If the [prepared statement] passed as the argument to
-**          [sqlite3_sql()] was compiled using either [sqlite3_prepare()] or
-**          [sqlite3_prepare16()], then [sqlite3_sql()] returns a NULL pointer.
-**
-** {H13103} The string returned by [sqlite3_sql(S)] is valid until the
-**          [prepared statement] S is deleted using [sqlite3_finalize(S)].
 */
 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200>
+** CAPI3REF: Determine If An SQL Statement Writes The Database
+**
+** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
+** and only if the [prepared statement] X makes no direct changes to
+** the content of the database file.
+**
+** Note that [application-defined SQL functions] or
+** [virtual tables] might change the database indirectly as a side effect.  
+** ^(For example, if an application defines a function "eval()" that 
+** calls [sqlite3_exec()], then the following SQL statement would
+** change the database file through side-effects:
+**
+** <blockquote><pre>
+**    SELECT eval('DELETE FROM t1') FROM t2;
+** </pre></blockquote>
+**
+** But because the [SELECT] statement does not change the database file
+** directly, sqlite3_stmt_readonly() would still return true.)^
+**
+** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
+** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
+** since the statements themselves do not actually modify the database but
+** rather they control the timing of when other statements modify the 
+** database.  ^The [ATTACH] and [DETACH] statements also cause
+** sqlite3_stmt_readonly() to return true since, while those statements
+** change the configuration of a database connection, they do not make 
+** changes to the content of the database files on disk.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Determine If A Prepared Statement Has Been Reset
+**
+** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
+** [prepared statement] S has been stepped at least once using 
+** [sqlite3_step(S)] but has not run to completion and/or has not 
+** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
+** interface returns false if S is a NULL pointer.  If S is not a 
+** NULL pointer and is not a pointer to a valid [prepared statement]
+** object, then the behavior is undefined and probably undesirable.
+**
+** This interface can be used in combination [sqlite3_next_stmt()]
+** to locate all prepared statements associated with a database 
+** connection that are in need of being reset.  This can be used,
+** for example, in diagnostic routines to search for prepared 
+** statements that are holding a transaction open.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Dynamically Typed Value Object
 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
 **
 ** SQLite uses the sqlite3_value object to represent all values
 ** that can be stored in a database table. SQLite uses dynamic typing
-** for the values it stores. Values stored in sqlite3_value objects
+** for the values it stores.  ^Values stored in sqlite3_value objects
 ** can be integers, floating point values, strings, BLOBs, or NULL.
 **
 ** An sqlite3_value object may be either "protected" or "unprotected".
@@ -3558,7 +3653,7 @@ SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
 ** whether or not it requires a protected sqlite3_value.
 **
 ** The terms "protected" and "unprotected" refer to whether or not
-** a mutex is held.  A internal mutex is held for a protected
+** a mutex is held.  An internal mutex is held for a protected
 ** sqlite3_value object but no mutex is held for an unprotected
 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
@@ -3567,12 +3662,12 @@ SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
 ** then there is no distinction between protected and unprotected
 ** sqlite3_value objects and they can be used interchangeably.  However,
 ** for maximum code portability it is recommended that applications
-** still make the distinction between between protected and unprotected
+** still make the distinction between protected and unprotected
 ** sqlite3_value objects even when not strictly required.
 **
-** The sqlite3_value objects that are passed as parameters into the
+** ^The sqlite3_value objects that are passed as parameters into the
 ** implementation of [application-defined SQL functions] are protected.
-** The sqlite3_value object returned by
+** ^The sqlite3_value object returned by
 ** [sqlite3_column_value()] is unprotected.
 ** Unprotected sqlite3_value objects may only be used with
 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
@@ -3582,10 +3677,10 @@ SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
 typedef struct Mem sqlite3_value;
 
 /*
-** CAPI3REF: SQL Function Context Object {H16001} <S20200>
+** CAPI3REF: SQL Function Context Object
 **
 ** The context in which an SQL function executes is stored in an
-** sqlite3_context object.  A pointer to an sqlite3_context object
+** sqlite3_context object.  ^A pointer to an sqlite3_context object
 ** is always first parameter to [application-defined SQL functions].
 ** The application-defined SQL function implementation will pass this
 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
@@ -3596,12 +3691,13 @@ typedef struct Mem sqlite3_value;
 typedef struct sqlite3_context sqlite3_context;
 
 /*
-** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300>
+** CAPI3REF: Binding Values To Prepared Statements
 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
 **
-** In the SQL strings input to [sqlite3_prepare_v2()] and its variants,
-** literals may be replaced by a parameter in one of these forms:
+** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
+** literals may be replaced by a [parameter] that matches one of following
+** templates:
 **
 ** <ul>
 ** <li>  ?
@@ -3611,142 +3707,80 @@ typedef struct sqlite3_context sqlite3_context;
 ** <li>  $VVV
 ** </ul>
 **
-** In the parameter forms shown above NNN is an integer literal,
-** and VVV is an alpha-numeric parameter name. The values of these
+** In the templates above, NNN represents an integer literal,
+** and VVV represents an alphanumeric identifier.)^  ^The values of these
 ** parameters (also called "host parameter names" or "SQL parameters")
 ** can be set using the sqlite3_bind_*() routines defined here.
 **
-** The first argument to the sqlite3_bind_*() routines is always
+** ^The first argument to the sqlite3_bind_*() routines is always
 ** a pointer to the [sqlite3_stmt] object returned from
 ** [sqlite3_prepare_v2()] or its variants.
 **
-** The second argument is the index of the SQL parameter to be set.
-** The leftmost SQL parameter has an index of 1.  When the same named
+** ^The second argument is the index of the SQL parameter to be set.
+** ^The leftmost SQL parameter has an index of 1.  ^When the same named
 ** SQL parameter is used more than once, second and subsequent
 ** occurrences have the same index as the first occurrence.
-** The index for named parameters can be looked up using the
-** [sqlite3_bind_parameter_index()] API if desired.  The index
+** ^The index for named parameters can be looked up using the
+** [sqlite3_bind_parameter_index()] API if desired.  ^The index
 ** for "?NNN" parameters is the value of NNN.
-** The NNN value must be between 1 and the [sqlite3_limit()]
+** ^The NNN value must be between 1 and the [sqlite3_limit()]
 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
 **
-** The third argument is the value to bind to the parameter.
+** ^The third argument is the value to bind to the parameter.
 **
-** In those routines that have a fourth argument, its value is the
+** ^(In those routines that have a fourth argument, its value is the
 ** number of bytes in the parameter.  To be clear: the value is the
-** number of <u>bytes</u> in the value, not the number of characters.
-** If the fourth parameter is negative, the length of the string is
+** number of <u>bytes</u> in the value, not the number of characters.)^
+** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** is negative, then the length of the string is
 ** the number of bytes up to the first zero terminator.
+** If the fourth parameter to sqlite3_bind_blob() is negative, then
+** the behavior is undefined.
+** If a non-negative fourth parameter is provided to sqlite3_bind_text()
+** or sqlite3_bind_text16() then that parameter must be the byte offset
+** where the NUL terminator would occur assuming the string were NUL
+** terminated.  If any NUL characters occur at byte offsets less than 
+** the value of the fourth parameter then the resulting string value will
+** contain embedded NULs.  The result of expressions involving strings
+** with embedded NULs is undefined.
 **
-** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
+** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
-** string after SQLite has finished with it. If the fifth argument is
+** string after SQLite has finished with it.  ^The destructor is called
+** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
+** sqlite3_bind_text(), or sqlite3_bind_text16() fails.  
+** ^If the fifth argument is
 ** the special value [SQLITE_STATIC], then SQLite assumes that the
 ** information is in static, unmanaged space and does not need to be freed.
-** If the fifth argument has the value [SQLITE_TRANSIENT], then
+** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
 ** SQLite makes its own private copy of the data immediately, before
 ** the sqlite3_bind_*() routine returns.
 **
-** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
-** is filled with zeroes.  A zeroblob uses a fixed amount of memory
+** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
+** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
 ** (just an integer to hold its size) while it is being processed.
 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
 ** content is later written using
 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
-** A negative value for the zeroblob results in a zero-length BLOB.
+** ^A negative value for the zeroblob results in a zero-length BLOB.
 **
-** The sqlite3_bind_*() routines must be called after
-** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
-** before [sqlite3_step()].
-** Bindings are not cleared by the [sqlite3_reset()] routine.
-** Unbound parameters are interpreted as NULL.
+** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
+** for the [prepared statement] or with a prepared statement for which
+** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
+** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
+** routine is passed a [prepared statement] that has been finalized, the
+** result is undefined and probably harmful.
 **
-** These routines return [SQLITE_OK] on success or an error code if
-** anything goes wrong.  [SQLITE_RANGE] is returned if the parameter
-** index is out of range.  [SQLITE_NOMEM] is returned if malloc() fails.
-** [SQLITE_MISUSE] might be returned if these routines are called on a
-** virtual machine that is the wrong state or which has already been finalized.
-** Detection of misuse is unreliable.  Applications should not depend
-** on SQLITE_MISUSE returns.  SQLITE_MISUSE is intended to indicate a
-** a logic error in the application.  Future versions of SQLite might
-** panic rather than return SQLITE_MISUSE.
+** ^Bindings are not cleared by the [sqlite3_reset()] routine.
+** ^Unbound parameters are interpreted as NULL.
+**
+** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
+** [error code] if anything goes wrong.
+** ^[SQLITE_RANGE] is returned if the parameter
+** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
 **
 ** See also: [sqlite3_bind_parameter_count()],
 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13506} The [SQL statement compiler] recognizes tokens of the forms
-**          "?", "?NNN", "$VVV", ":VVV", and "@VVV" as SQL parameters,
-**          where NNN is any sequence of one or more digits
-**          and where VVV is any sequence of one or more alphanumeric
-**          characters or "::" optionally followed by a string containing
-**          no spaces and contained within parentheses.
-**
-** {H13509} The initial value of an SQL parameter is NULL.
-**
-** {H13512} The index of an "?" SQL parameter is one larger than the
-**          largest index of SQL parameter to the left, or 1 if
-**          the "?" is the leftmost SQL parameter.
-**
-** {H13515} The index of an "?NNN" SQL parameter is the integer NNN.
-**
-** {H13518} The index of an ":VVV", "$VVV", or "@VVV" SQL parameter is
-**          the same as the index of leftmost occurrences of the same
-**          parameter, or one more than the largest index over all
-**          parameters to the left if this is the first occurrence
-**          of this parameter, or 1 if this is the leftmost parameter.
-**
-** {H13521} The [SQL statement compiler] fails with an [SQLITE_RANGE]
-**          error if the index of an SQL parameter is less than 1
-**          or greater than the compile-time SQLITE_MAX_VARIABLE_NUMBER
-**          parameter.
-**
-** {H13524} Calls to [sqlite3_bind_text | sqlite3_bind(S,N,V,...)]
-**          associate the value V with all SQL parameters having an
-**          index of N in the [prepared statement] S.
-**
-** {H13527} Calls to [sqlite3_bind_text | sqlite3_bind(S,N,...)]
-**          override prior calls with the same values of S and N.
-**
-** {H13530} Bindings established by [sqlite3_bind_text | sqlite3_bind(S,...)]
-**          persist across calls to [sqlite3_reset(S)].
-**
-** {H13533} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] SQLite binds the first L
-**          bytes of the BLOB or string pointed to by V, when L
-**          is non-negative.
-**
-** {H13536} In calls to [sqlite3_bind_text(S,N,V,L,D)] or
-**          [sqlite3_bind_text16(S,N,V,L,D)] SQLite binds characters
-**          from V through the first zero character when L is negative.
-**
-** {H13539} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] when D is the special
-**          constant [SQLITE_STATIC], SQLite assumes that the value V
-**          is held in static unmanaged space that will not change
-**          during the lifetime of the binding.
-**
-** {H13542} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] when D is the special
-**          constant [SQLITE_TRANSIENT], the routine makes a
-**          private copy of the value V before it returns.
-**
-** {H13545} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] when D is a pointer to
-**          a function, SQLite invokes that function to destroy the
-**          value V after it has finished using the value V.
-**
-** {H13548} In calls to [sqlite3_bind_zeroblob(S,N,V,L)] the value bound
-**          is a BLOB of L bytes, or a zero-length BLOB if L is negative.
-**
-** {H13551} In calls to [sqlite3_bind_value(S,N,V)] the V argument may
-**          be either a [protected sqlite3_value] object or an
-**          [unprotected sqlite3_value] object.
 */
 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
@@ -3759,48 +3793,42 @@ SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
 
 /*
-** CAPI3REF: Number Of SQL Parameters {H13600} <S70300>
+** CAPI3REF: Number Of SQL Parameters
 **
-** This routine can be used to find the number of [SQL parameters]
+** ^This routine can be used to find the number of [SQL parameters]
 ** in a [prepared statement].  SQL parameters are tokens of the
 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
 ** placeholders for values that are [sqlite3_bind_blob | bound]
 ** to the parameters at a later time.
 **
-** This routine actually returns the index of the largest (rightmost)
+** ^(This routine actually returns the index of the largest (rightmost)
 ** parameter. For all forms except ?NNN, this will correspond to the
-** number of unique parameters.  If parameters of the ?NNN are used,
-** there may be gaps in the list.
+** number of unique parameters.  If parameters of the ?NNN form are used,
+** there may be gaps in the list.)^
 **
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_name()], and
 ** [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13601} The [sqlite3_bind_parameter_count(S)] interface returns
-**          the largest index of all SQL parameters in the
-**          [prepared statement] S, or 0 if S contains no SQL parameters.
 */
 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Name Of A Host Parameter {H13620} <S70300>
+** CAPI3REF: Name Of A Host Parameter
 **
-** This routine returns a pointer to the name of the n-th
-** [SQL parameter] in a [prepared statement].
-** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** ^The sqlite3_bind_parameter_name(P,N) interface returns
+** the name of the N-th [SQL parameter] in the [prepared statement] P.
+** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
 ** respectively.
 ** In other words, the initial ":" or "$" or "@" or "?"
-** is included as part of the name.
-** Parameters of the form "?" without a following integer have no name
-** and are also referred to as "anonymous parameters".
+** is included as part of the name.)^
+** ^Parameters of the form "?" without a following integer have no name
+** and are referred to as "nameless" or "anonymous parameters".
 **
-** The first host parameter has an index of 1, not 0.
+** ^The first host parameter has an index of 1, not 0.
 **
-** If the value n is out of range or if the n-th parameter is
-** nameless, then NULL is returned.  The returned string is
+** ^If the value N is out of range or if the N-th parameter is
+** nameless, then NULL is returned.  ^The returned string is
 ** always in UTF-8 encoding even if the named parameter was
 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
 ** [sqlite3_prepare16_v2()].
@@ -3808,214 +3836,118 @@ SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_count()], and
 ** [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13621} The [sqlite3_bind_parameter_name(S,N)] interface returns
-**          a UTF-8 rendering of the name of the SQL parameter in
-**          the [prepared statement] S having index N, or
-**          NULL if there is no SQL parameter with index N or if the
-**          parameter with index N is an anonymous parameter "?".
 */
 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
 
 /*
-** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300>
+** CAPI3REF: Index Of A Parameter With A Given Name
 **
-** Return the index of an SQL parameter given its name.  The
+** ^Return the index of an SQL parameter given its name.  ^The
 ** index value returned is suitable for use as the second
-** parameter to [sqlite3_bind_blob|sqlite3_bind()].  A zero
-** is returned if no matching parameter is found.  The parameter
+** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
+** is returned if no matching parameter is found.  ^The parameter
 ** name must be given in UTF-8 even if the original statement
 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
 **
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_count()], and
 ** [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13641} The [sqlite3_bind_parameter_index(S,N)] interface returns
-**          the index of SQL parameter in the [prepared statement]
-**          S whose name matches the UTF-8 string N, or 0 if there is
-**          no match.
 */
 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
 
 /*
-** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300>
+** CAPI3REF: Reset All Bindings On A Prepared Statement
 **
-** Contrary to the intuition of many, [sqlite3_reset()] does not reset
+** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
-** Use this routine to reset all host parameters to NULL.
-**
-** INVARIANTS:
-**
-** {H13661} The [sqlite3_clear_bindings(S)] interface resets all SQL
-**          parameter bindings in the [prepared statement] S back to NULL.
+** ^Use this routine to reset all host parameters to NULL.
 */
 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700>
+** CAPI3REF: Number Of Columns In A Result Set
 **
-** Return the number of columns in the result set returned by the
-** [prepared statement]. This routine returns 0 if pStmt is an SQL
+** ^Return the number of columns in the result set returned by the
+** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
 ** statement that does not return data (for example an [UPDATE]).
 **
-** INVARIANTS:
-**
-** {H13711} The [sqlite3_column_count(S)] interface returns the number of
-**          columns in the result set generated by the [prepared statement] S,
-**          or 0 if S does not generate a result set.
+** See also: [sqlite3_data_count()]
 */
 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Column Names In A Result Set {H13720} <S10700>
+** CAPI3REF: Column Names In A Result Set
 **
-** These routines return the name assigned to a particular column
-** in the result set of a [SELECT] statement.  The sqlite3_column_name()
+** ^These routines return the name assigned to a particular column
+** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
 ** interface returns a pointer to a zero-terminated UTF-8 string
 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
-** UTF-16 string.  The first parameter is the [prepared statement]
-** that implements the [SELECT] statement. The second parameter is the
-** column number.  The leftmost column is number 0.
+** UTF-16 string.  ^The first parameter is the [prepared statement]
+** that implements the [SELECT] statement. ^The second parameter is the
+** column number.  ^The leftmost column is number 0.
 **
-** The returned string pointer is valid until either the [prepared statement]
-** is destroyed by [sqlite3_finalize()] or until the next call to
+** ^The returned string pointer is valid until either the [prepared statement]
+** is destroyed by [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the next call to
 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
 **
-** If sqlite3_malloc() fails during the processing of either routine
+** ^If sqlite3_malloc() fails during the processing of either routine
 ** (for example during a conversion from UTF-8 to UTF-16) then a
 ** NULL pointer is returned.
 **
-** The name of a result column is the value of the "AS" clause for
+** ^The name of a result column is the value of the "AS" clause for
 ** that column, if there is an AS clause.  If there is no AS clause
 ** then the name of the column is unspecified and may change from
 ** one release of SQLite to the next.
-**
-** INVARIANTS:
-**
-** {H13721} A successful invocation of the [sqlite3_column_name(S,N)]
-**          interface returns the name of the Nth column (where 0 is
-**          the leftmost column) for the result set of the
-**          [prepared statement] S as a zero-terminated UTF-8 string.
-**
-** {H13723} A successful invocation of the [sqlite3_column_name16(S,N)]
-**          interface returns the name of the Nth column (where 0 is
-**          the leftmost column) for the result set of the
-**          [prepared statement] S as a zero-terminated UTF-16 string
-**          in the native byte order.
-**
-** {H13724} The [sqlite3_column_name()] and [sqlite3_column_name16()]
-**          interfaces return a NULL pointer if they are unable to
-**          allocate memory to hold their normal return strings.
-**
-** {H13725} If the N parameter to [sqlite3_column_name(S,N)] or
-**          [sqlite3_column_name16(S,N)] is out of range, then the
-**          interfaces return a NULL pointer.
-**
-** {H13726} The strings returned by [sqlite3_column_name(S,N)] and
-**          [sqlite3_column_name16(S,N)] are valid until the next
-**          call to either routine with the same S and N parameters
-**          or until [sqlite3_finalize(S)] is called.
-**
-** {H13727} When a result column of a [SELECT] statement contains
-**          an AS clause, the name of that column is the identifier
-**          to the right of the AS keyword.
 */
 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
 
 /*
-** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700>
+** CAPI3REF: Source Of Data In A Query Result
 **
-** These routines provide a means to determine what column of what
-** table in which database a result of a [SELECT] statement comes from.
-** The name of the database or table or column can be returned as
-** either a UTF-8 or UTF-16 string.  The _database_ routines return
+** ^These routines provide a means to determine the database, table, and
+** table column that is the origin of a particular result column in
+** [SELECT] statement.
+** ^The name of the database or table or column can be returned as
+** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
 ** the database name, the _table_ routines return the table name, and
 ** the origin_ routines return the column name.
-** The returned string is valid until the [prepared statement] is destroyed
-** using [sqlite3_finalize()] or until the same information is requested
+** ^The returned string is valid until the [prepared statement] is destroyed
+** using [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the same information is requested
 ** again in a different encoding.
 **
-** The names returned are the original un-aliased names of the
+** ^The names returned are the original un-aliased names of the
 ** database, table, and column.
 **
-** The first argument to the following calls is a [prepared statement].
-** These functions return information about the Nth column returned by
+** ^The first argument to these interfaces is a [prepared statement].
+** ^These functions return information about the Nth result column returned by
 ** the statement, where N is the second function argument.
+** ^The left-most column is column 0 for these routines.
 **
-** If the Nth column returned by the statement is an expression or
+** ^If the Nth column returned by the statement is an expression or
 ** subquery and is not a column value, then all of these functions return
-** NULL.  These routine might also return NULL if a memory allocation error
-** occurs.  Otherwise, they return the name of the attached database, table
-** and column that query result column was extracted from.
+** NULL.  ^These routine might also return NULL if a memory allocation error
+** occurs.  ^Otherwise, they return the name of the attached database, table,
+** or column that query result column was extracted from.
 **
-** As with all other SQLite APIs, those postfixed with "16" return
-** UTF-16 encoded strings, the other functions return UTF-8. {END}
+** ^As with all other SQLite APIs, those whose names end with "16" return
+** UTF-16 encoded strings and the other functions return UTF-8.
 **
-** These APIs are only available if the library was compiled with the
-** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
+** ^These APIs are only available if the library was compiled with the
+** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
 **
-** {A13751}
 ** If two or more threads call one or more of these routines against the same
 ** prepared statement and column at the same time then the results are
 ** undefined.
 **
-** INVARIANTS:
-**
-** {H13741} The [sqlite3_column_database_name(S,N)] interface returns either
-**          the UTF-8 zero-terminated name of the database from which the
-**          Nth result column of the [prepared statement] S is extracted,
-**          or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13742} The [sqlite3_column_database_name16(S,N)] interface returns either
-**          the UTF-16 native byte order zero-terminated name of the database
-**          from which the Nth result column of the [prepared statement] S is
-**          extracted, or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13743} The [sqlite3_column_table_name(S,N)] interface returns either
-**          the UTF-8 zero-terminated name of the table from which the
-**          Nth result column of the [prepared statement] S is extracted,
-**          or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13744} The [sqlite3_column_table_name16(S,N)] interface returns either
-**          the UTF-16 native byte order zero-terminated name of the table
-**          from which the Nth result column of the [prepared statement] S is
-**          extracted, or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13745} The [sqlite3_column_origin_name(S,N)] interface returns either
-**          the UTF-8 zero-terminated name of the table column from which the
-**          Nth result column of the [prepared statement] S is extracted,
-**          or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13746} The [sqlite3_column_origin_name16(S,N)] interface returns either
-**          the UTF-16 native byte order zero-terminated name of the table
-**          column from which the Nth result column of the
-**          [prepared statement] S is extracted, or NULL if the Nth column
-**          of S is a general expression or if unable to allocate memory
-**          to store the name.
-**
-** {H13748} The return values from
-**          [sqlite3_column_database_name | column metadata interfaces]
-**          are valid for the lifetime of the [prepared statement]
-**          or until the encoding is changed by another metadata
-**          interface call for the same prepared statement and column.
-**
-** ASSUMPTIONS:
-**
-** {A13751} If two or more threads call one or more
-**          [sqlite3_column_database_name | column metadata interfaces]
-**          for the same [prepared statement] and result column
-**          at the same time then the results are undefined.
+** If two or more threads call one or more
+** [sqlite3_column_database_name | column metadata interfaces]
+** for the same [prepared statement] and result column
+** at the same time then the results are undefined.
 */
 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
@@ -4025,17 +3957,17 @@ SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
 
 /*
-** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700>
+** CAPI3REF: Declared Datatype Of A Query Result
 **
-** The first parameter is a [prepared statement].
+** ^(The first parameter is a [prepared statement].
 ** If this statement is a [SELECT] statement and the Nth column of the
 ** returned result set of that [SELECT] is a table column (not an
 ** expression or subquery) then the declared type of the table
-** column is returned.  If the Nth column of the result set is an
+** column is returned.)^  ^If the Nth column of the result set is an
 ** expression or subquery, then a NULL pointer is returned.
-** The returned string is always UTF-8 encoded. {END}
+** ^The returned string is always UTF-8 encoded.
 **
-** For example, given the database schema:
+** ^(For example, given the database schema:
 **
 ** CREATE TABLE t1(c1 VARIANT);
 **
@@ -4044,41 +3976,20 @@ SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
 ** SELECT c1 + 1, c1 FROM t1;
 **
 ** this routine would return the string "VARIANT" for the second result
-** column (i==1), and a NULL pointer for the first result column (i==0).
+** column (i==1), and a NULL pointer for the first result column (i==0).)^
 **
-** SQLite uses dynamic run-time typing.  So just because a column
+** ^SQLite uses dynamic run-time typing.  ^So just because a column
 ** is declared to contain a particular type does not mean that the
 ** data stored in that column is of the declared type.  SQLite is
-** strongly typed, but the typing is dynamic not static.  Type
+** strongly typed, but the typing is dynamic not static.  ^Type
 ** is associated with individual values, not with the containers
 ** used to hold those values.
-**
-** INVARIANTS:
-**
-** {H13761}  A successful call to [sqlite3_column_decltype(S,N)] returns a
-**           zero-terminated UTF-8 string containing the declared datatype
-**           of the table column that appears as the Nth column (numbered
-**           from 0) of the result set to the [prepared statement] S.
-**
-** {H13762}  A successful call to [sqlite3_column_decltype16(S,N)]
-**           returns a zero-terminated UTF-16 native byte order string
-**           containing the declared datatype of the table column that appears
-**           as the Nth column (numbered from 0) of the result set to the
-**           [prepared statement] S.
-**
-** {H13763}  If N is less than 0 or N is greater than or equal to
-**           the number of columns in the [prepared statement] S,
-**           or if the Nth column of S is an expression or subquery rather
-**           than a table column, or if a memory allocation failure
-**           occurs during encoding conversions, then
-**           calls to [sqlite3_column_decltype(S,N)] or
-**           [sqlite3_column_decltype16(S,N)] return NULL.
 */
 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 
 /*
-** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000>
+** CAPI3REF: Evaluate An SQL Statement
 **
 ** After a [prepared statement] has been prepared using either
 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
@@ -4092,35 +4003,35 @@ SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 ** new "v2" interface is recommended for new applications but the legacy
 ** interface will continue to be supported.
 **
-** In the legacy interface, the return value will be either [SQLITE_BUSY],
+** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
-** With the "v2" interface, any of the other [result codes] or
+** ^With the "v2" interface, any of the other [result codes] or
 ** [extended result codes] might be returned as well.
 **
-** [SQLITE_BUSY] means that the database engine was unable to acquire the
-** database locks it needs to do its job.  If the statement is a [COMMIT]
+** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
+** database locks it needs to do its job.  ^If the statement is a [COMMIT]
 ** or occurs outside of an explicit transaction, then you can retry the
-** statement.  If the statement is not a [COMMIT] and occurs within a
+** statement.  If the statement is not a [COMMIT] and occurs within an
 ** explicit transaction then you should rollback the transaction before
 ** continuing.
 **
-** [SQLITE_DONE] means that the statement has finished executing
+** ^[SQLITE_DONE] means that the statement has finished executing
 ** successfully.  sqlite3_step() should not be called again on this virtual
 ** machine without first calling [sqlite3_reset()] to reset the virtual
 ** machine back to its initial state.
 **
-** If the SQL statement being executed returns any data, then [SQLITE_ROW]
+** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
 ** is returned each time a new row of data is ready for processing by the
 ** caller. The values may be accessed using the [column access functions].
 ** sqlite3_step() is called again to retrieve the next row of data.
 **
-** [SQLITE_ERROR] means that a run-time error (such as a constraint
+** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
 ** violation) has occurred.  sqlite3_step() should not be called again on
 ** the VM. More information may be found by calling [sqlite3_errmsg()].
-** With the legacy interface, a more specific error code (for example,
+** ^With the legacy interface, a more specific error code (for example,
 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
 ** can be obtained by calling [sqlite3_reset()] on the
-** [prepared statement].  In the "v2" interface,
+** [prepared statement].  ^In the "v2" interface,
 ** the more specific error code is returned directly by sqlite3_step().
 **
 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
@@ -4130,6 +4041,18 @@ SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 ** be the case that the same database connection is being used by two or
 ** more threads at the same moment in time.
 **
+** For all versions of SQLite up to and including 3.6.23.1, a call to
+** [sqlite3_reset()] was required after sqlite3_step() returned anything
+** other than [SQLITE_ROW] before any subsequent invocation of
+** sqlite3_step().  Failure to reset the prepared statement using 
+** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
+** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
+** calling [sqlite3_reset()] automatically in this circumstance rather
+** than returning [SQLITE_MISUSE].  This is not considered a compatibility
+** break because any application that ever receives an SQLITE_MISUSE error
+** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
+** can be used to restore the legacy behavior.
+**
 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
 ** API always returns a generic error code, [SQLITE_ERROR], following any
 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
@@ -4141,59 +4064,34 @@ SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
 ** then the more specific [error codes] are returned directly
 ** by sqlite3_step().  The use of the "v2" interface is recommended.
-**
-** INVARIANTS:
-**
-** {H13202}  If the [prepared statement] S is ready to be run, then
-**           [sqlite3_step(S)] advances that prepared statement until
-**           completion or until it is ready to return another row of the
-**           result set, or until an [sqlite3_interrupt | interrupt]
-**           or a run-time error occurs.
-**
-** {H15304}  When a call to [sqlite3_step(S)] causes the [prepared statement]
-**           S to run to completion, the function returns [SQLITE_DONE].
-**
-** {H15306}  When a call to [sqlite3_step(S)] stops because it is ready to
-**           return another row of the result set, it returns [SQLITE_ROW].
-**
-** {H15308}  If a call to [sqlite3_step(S)] encounters an
-**           [sqlite3_interrupt | interrupt] or a run-time error,
-**           it returns an appropriate error code that is not one of
-**           [SQLITE_OK], [SQLITE_ROW], or [SQLITE_DONE].
-**
-** {H15310}  If an [sqlite3_interrupt | interrupt] or a run-time error
-**           occurs during a call to [sqlite3_step(S)]
-**           for a [prepared statement] S created using
-**           legacy interfaces [sqlite3_prepare()] or
-**           [sqlite3_prepare16()], then the function returns either
-**           [SQLITE_ERROR], [SQLITE_BUSY], or [SQLITE_MISUSE].
 */
 SQLITE_API int sqlite3_step(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Number of columns in a result set {H13770} <S10700>
+** CAPI3REF: Number of columns in a result set
 **
-** Returns the number of values in the current row of the result set.
+** ^The sqlite3_data_count(P) interface returns the number of columns in the
+** current row of the result set of [prepared statement] P.
+** ^If prepared statement P does not have results ready to return
+** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
+** interfaces) then sqlite3_data_count(P) returns 0.
+** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
+** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
+** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
+** will return non-zero if previous call to [sqlite3_step](P) returned
+** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
+** where it always returns zero since each step of that multi-step
+** pragma returns 0 columns of data.
 **
-** INVARIANTS:
-**
-** {H13771}  After a call to [sqlite3_step(S)] that returns [SQLITE_ROW],
-**           the [sqlite3_data_count(S)] routine will return the same value
-**           as the [sqlite3_column_count(S)] function.
-**
-** {H13772}  After [sqlite3_step(S)] has returned any value other than
-**           [SQLITE_ROW] or before [sqlite3_step(S)] has been called on the
-**           [prepared statement] for the first time since it was
-**           [sqlite3_prepare | prepared] or [sqlite3_reset | reset],
-**           the [sqlite3_data_count(S)] routine returns zero.
+** See also: [sqlite3_column_count()]
 */
 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120>
+** CAPI3REF: Fundamental Datatypes
 ** KEYWORDS: SQLITE_TEXT
 **
-** {H10266} Every value in SQLite has one of five fundamental datatypes:
+** ^(Every value in SQLite has one of five fundamental datatypes:
 **
 ** <ul>
 ** <li> 64-bit signed integer
@@ -4201,7 +4099,7 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** <li> string
 ** <li> BLOB
 ** <li> NULL
-** </ul> {END}
+** </ul>)^
 **
 ** These constants are codes for each of those types.
 **
@@ -4222,17 +4120,19 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 #define SQLITE3_TEXT     3
 
 /*
-** CAPI3REF: Result Values From A Query {H13800} <S10700>
+** CAPI3REF: Result Values From A Query
 ** KEYWORDS: {column access functions}
 **
-** These routines form the "result set query" interface.
+** These routines form the "result set" interface.
 **
-** These routines return information about a single column of the current
-** result row of a query.  In every case the first argument is a pointer
+** ^These routines return information about a single column of the current
+** result row of a query.  ^In every case the first argument is a pointer
 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
 ** and the second argument is the index of the column for which information
-** should be returned.  The leftmost column of the result set has the index 0.
+** should be returned. ^The leftmost column of the result set has the index 0.
+** ^The number of columns in the result can be determined using
+** [sqlite3_column_count()].
 **
 ** If the SQL statement does not currently point to a valid row, or if the
 ** column index is out of range, the result is undefined.
@@ -4246,9 +4146,9 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** are called from a different thread while any of these routines
 ** are pending, then the results are undefined.
 **
-** The sqlite3_column_type() routine returns the
+** ^The sqlite3_column_type() routine returns the
 ** [SQLITE_INTEGER | datatype code] for the initial data type
-** of the result column.  The returned value is one of [SQLITE_INTEGER],
+** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
 ** returned by sqlite3_column_type() is only meaningful if no type
 ** conversions have occurred as described below.  After a type conversion,
@@ -4256,27 +4156,35 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** versions of SQLite may change the behavior of sqlite3_column_type()
 ** following a type conversion.
 **
-** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
+** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
 ** routine returns the number of bytes in that BLOB or string.
-** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
+** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
 ** the string to UTF-8 and then returns the number of bytes.
-** If the result is a numeric value then sqlite3_column_bytes() uses
+** ^If the result is a numeric value then sqlite3_column_bytes() uses
 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
 ** the number of bytes in that string.
-** The value returned does not include the zero terminator at the end
-** of the string.  For clarity: the value returned is the number of
+** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
+**
+** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
+** the string to UTF-16 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes16() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
+**
+** ^The values returned by [sqlite3_column_bytes()] and 
+** [sqlite3_column_bytes16()] do not include the zero terminators at the end
+** of the string.  ^For clarity: the values returned by
+** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
 ** bytes in the string, not the number of characters.
 **
-** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
-** even empty strings, are always zero terminated.  The return
-** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary
-** pointer, possibly even a NULL pointer.
+** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
+** even empty strings, are always zero-terminated.  ^The return
+** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
 **
-** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
-** but leaves the result in UTF-16 in native byte order instead of UTF-8.
-** The zero terminator is not included in this count.
-**
-** The object returned by [sqlite3_column_value()] is an
+** ^The object returned by [sqlite3_column_value()] is an
 ** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
 ** If the [unprotected sqlite3_value] object returned by
@@ -4284,10 +4192,10 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
 ** or [sqlite3_value_bytes()], then the behavior is undefined.
 **
-** These routines attempt to convert the value where appropriate.  For
+** These routines attempt to convert the value where appropriate.  ^For
 ** example, if the internal representation is FLOAT and a text result
 ** is requested, [sqlite3_snprintf()] is used internally to perform the
-** conversion automatically.  The following table details the conversions
+** conversion automatically.  ^(The following table details the conversions
 ** that are applied:
 **
 ** <blockquote>
@@ -4311,7 +4219,7 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
 ** </table>
-** </blockquote>
+** </blockquote>)^
 **
 ** The table above makes reference to standard C library functions atoi()
 ** and atof().  SQLite does not really use these functions.  It has its
@@ -4337,9 +4245,9 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 **      to UTF-8.</li>
 ** </ul>
 **
-** Conversions between UTF-16be and UTF-16le are always done in place and do
+** ^Conversions between UTF-16be and UTF-16le are always done in place and do
 ** not invalidate a prior pointer, though of course the content of the buffer
-** that the prior pointer points to will have been modified.  Other kinds
+** that the prior pointer references will have been modified.  Other kinds
 ** of conversion are done in place when it is possible, but sometimes they
 ** are not possible and in those cases prior pointers are invalidated.
 **
@@ -4360,73 +4268,18 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
 ** with calls to sqlite3_column_bytes().
 **
-** The pointers returned are valid until a type conversion occurs as
+** ^The pointers returned are valid until a type conversion occurs as
 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
-** [sqlite3_finalize()] is called.  The memory space used to hold strings
+** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
 ** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
 ** [sqlite3_free()].
 **
-** If a memory allocation error occurs during the evaluation of any
+** ^(If a memory allocation error occurs during the evaluation of any
 ** of these routines, a default value is returned.  The default value
 ** is either the integer 0, the floating point number 0.0, or a NULL
 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
-** [SQLITE_NOMEM].
-**
-** INVARIANTS:
-**
-** {H13803} The [sqlite3_column_blob(S,N)] interface converts the
-**          Nth column in the current row of the result set for
-**          the [prepared statement] S into a BLOB and then returns a
-**          pointer to the converted value.
-**
-** {H13806} The [sqlite3_column_bytes(S,N)] interface returns the
-**          number of bytes in the BLOB or string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_column_blob(S,N)] or
-**          [sqlite3_column_text(S,N)].
-**
-** {H13809} The [sqlite3_column_bytes16(S,N)] interface returns the
-**          number of bytes in the string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_column_text16(S,N)].
-**
-** {H13812} The [sqlite3_column_double(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a floating point value and
-**          returns a copy of that value.
-**
-** {H13815} The [sqlite3_column_int(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a 64-bit signed integer and
-**          returns the lower 32 bits of that integer.
-**
-** {H13818} The [sqlite3_column_int64(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a 64-bit signed integer and
-**          returns a copy of that integer.
-**
-** {H13821} The [sqlite3_column_text(S,N)] interface converts the
-**          Nth column in the current row of the result set for
-**          the [prepared statement] S into a zero-terminated UTF-8
-**          string and returns a pointer to that string.
-**
-** {H13824} The [sqlite3_column_text16(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a zero-terminated 2-byte
-**          aligned UTF-16 native byte order string and returns
-**          a pointer to that string.
-**
-** {H13827} The [sqlite3_column_type(S,N)] interface returns
-**          one of [SQLITE_NULL], [SQLITE_INTEGER], [SQLITE_FLOAT],
-**          [SQLITE_TEXT], or [SQLITE_BLOB] as appropriate for
-**          the Nth column in the current row of the result set for
-**          the [prepared statement] S.
-**
-** {H13830} The [sqlite3_column_value(S,N)] interface returns a
-**          pointer to an [unprotected sqlite3_value] object for the
-**          Nth column in the current row of the result set for
-**          the [prepared statement] S.
+** [SQLITE_NOMEM].)^
 */
 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
@@ -4440,200 +4293,145 @@ SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
 
 /*
-** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100>
+** CAPI3REF: Destroy A Prepared Statement Object
 **
-** The sqlite3_finalize() function is called to delete a [prepared statement].
-** If the statement was executed successfully or not executed at all, then
-** SQLITE_OK is returned. If execution of the statement failed then an
-** [error code] or [extended error code] is returned.
+** ^The sqlite3_finalize() function is called to delete a [prepared statement].
+** ^If the most recent evaluation of the statement encountered no errors
+** or if the statement is never been evaluated, then sqlite3_finalize() returns
+** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
+** sqlite3_finalize(S) returns the appropriate [error code] or
+** [extended error code].
 **
-** This routine can be called at any point during the execution of the
-** [prepared statement].  If the virtual machine has not
-** completed execution when this routine is called, that is like
-** encountering an error or an [sqlite3_interrupt | interrupt].
-** Incomplete updates may be rolled back and transactions canceled,
-** depending on the circumstances, and the
-** [error code] returned will be [SQLITE_ABORT].
+** ^The sqlite3_finalize(S) routine can be called at any point during
+** the life cycle of [prepared statement] S:
+** before statement S is ever evaluated, after
+** one or more calls to [sqlite3_reset()], or after any call
+** to [sqlite3_step()] regardless of whether or not the statement has
+** completed execution.
 **
-** INVARIANTS:
+** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
 **
-** {H11302} The [sqlite3_finalize(S)] interface destroys the
-**          [prepared statement] S and releases all
-**          memory and file resources held by that object.
-**
-** {H11304} If the most recent call to [sqlite3_step(S)] for the
-**          [prepared statement] S returned an error,
-**          then [sqlite3_finalize(S)] returns that same error.
+** The application must finalize every [prepared statement] in order to avoid
+** resource leaks.  It is a grievous error for the application to try to use
+** a prepared statement after it has been finalized.  Any use of a prepared
+** statement after it has been finalized can result in undefined and
+** undesirable behavior such as segfaults and heap corruption.
 */
 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300>
+** CAPI3REF: Reset A Prepared Statement Object
 **
 ** The sqlite3_reset() function is called to reset a [prepared statement]
 ** object back to its initial state, ready to be re-executed.
-** Any SQL statement variables that had values bound to them using
+** ^Any SQL statement variables that had values bound to them using
 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
 ** Use [sqlite3_clear_bindings()] to reset the bindings.
 **
-** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S
-**          back to the beginning of its program.
+** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
+** back to the beginning of its program.
 **
-** {H11334} If the most recent call to [sqlite3_step(S)] for the
-**          [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
-**          or if [sqlite3_step(S)] has never before been called on S,
-**          then [sqlite3_reset(S)] returns [SQLITE_OK].
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
+** or if [sqlite3_step(S)] has never before been called on S,
+** then [sqlite3_reset(S)] returns [SQLITE_OK].
 **
-** {H11336} If the most recent call to [sqlite3_step(S)] for the
-**          [prepared statement] S indicated an error, then
-**          [sqlite3_reset(S)] returns an appropriate [error code].
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S indicated an error, then
+** [sqlite3_reset(S)] returns an appropriate [error code].
 **
-** {H11338} The [sqlite3_reset(S)] interface does not change the values
-**          of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
+** ^The [sqlite3_reset(S)] interface does not change the values
+** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
 */
 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200>
+** CAPI3REF: Create Or Redefine SQL Functions
 ** KEYWORDS: {function creation routines}
 ** KEYWORDS: {application-defined SQL function}
 ** KEYWORDS: {application-defined SQL functions}
 **
-** These two functions (collectively known as "function creation routines")
+** ^These functions (collectively known as "function creation routines")
 ** are used to add SQL functions or aggregates or to redefine the behavior
-** of existing SQL functions or aggregates.  The only difference between the
-** two is that the second parameter, the name of the (scalar) function or
-** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16
-** for sqlite3_create_function16().
+** of existing SQL functions or aggregates.  The only differences between
+** these routines are the text encoding expected for
+** the second parameter (the name of the function being created)
+** and the presence or absence of a destructor callback for
+** the application data pointer.
 **
-** The first parameter is the [database connection] to which the SQL
-** function is to be added.  If a single program uses more than one database
-** connection internally, then SQL functions must be added individually to
-** each database connection.
+** ^The first parameter is the [database connection] to which the SQL
+** function is to be added.  ^If an application uses more than one database
+** connection then application-defined SQL functions must be added
+** to each database connection separately.
 **
-** The second parameter is the name of the SQL function to be created or
-** redefined.  The length of the name is limited to 255 bytes, exclusive of
-** the zero-terminator.  Note that the name length limit is in bytes, not
-** characters.  Any attempt to create a function with a longer name
-** will result in [SQLITE_ERROR] being returned.
+** ^The second parameter is the name of the SQL function to be created or
+** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
+** representation, exclusive of the zero-terminator.  ^Note that the name
+** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.  
+** ^Any attempt to create a function with a longer name
+** will result in [SQLITE_MISUSE] being returned.
 **
-** The third parameter (nArg)
+** ^The third parameter (nArg)
 ** is the number of arguments that the SQL function or
-** aggregate takes. If this parameter is negative, then the SQL function or
-** aggregate may take any number of arguments.
+** aggregate takes. ^If this parameter is -1, then the SQL function or
+** aggregate may take any number of arguments between 0 and the limit
+** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
+** parameter is less than -1 or greater than 127 then the behavior is
+** undefined.
 **
-** The fourth parameter, eTextRep, specifies what
+** ^The fourth parameter, eTextRep, specifies what
 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
-** its parameters.  Any SQL function implementation should be able to work
-** work with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
-** more efficient with one encoding than another.  It is allowed to
+** its parameters.  Every SQL function implementation must be able to work
+** with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
+** more efficient with one encoding than another.  ^An application may
 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
 ** times with the same function but with different values of eTextRep.
-** When multiple implementations of the same function are available, SQLite
+** ^When multiple implementations of the same function are available, SQLite
 ** will pick the one that involves the least amount of data conversion.
 ** If there is only a single implementation which does not care what text
 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
 **
-** The fifth parameter is an arbitrary pointer.  The implementation of the
-** function can gain access to this pointer using [sqlite3_user_data()].
+** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
+** function can gain access to this pointer using [sqlite3_user_data()].)^
 **
-** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
+** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
 ** pointers to C-language functions that implement the SQL function or
-** aggregate. A scalar SQL function requires an implementation of the xFunc
-** callback only, NULL pointers should be passed as the xStep and xFinal
-** parameters. An aggregate SQL function requires an implementation of xStep
-** and xFinal and NULL should be passed for xFunc. To delete an existing
-** SQL function or aggregate, pass NULL for all three function callbacks.
+** aggregate. ^A scalar SQL function requires an implementation of the xFunc
+** callback only; NULL pointers must be passed as the xStep and xFinal
+** parameters. ^An aggregate SQL function requires an implementation of xStep
+** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
+** SQL function or aggregate, pass NULL pointers for all three function
+** callbacks.
 **
-** It is permitted to register multiple implementations of the same
+** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
+** then it is destructor for the application data pointer. 
+** The destructor is invoked when the function is deleted, either by being
+** overloaded or when the database connection closes.)^
+** ^The destructor is also invoked if the call to
+** sqlite3_create_function_v2() fails.
+** ^When the destructor callback of the tenth parameter is invoked, it
+** is passed a single argument which is a copy of the application data 
+** pointer which was the fifth parameter to sqlite3_create_function_v2().
+**
+** ^It is permitted to register multiple implementations of the same
 ** functions with the same name but with either differing numbers of
-** arguments or differing preferred text encodings.  SQLite will use
-** the implementation most closely matches the way in which the
-** SQL function is used.  A function implementation with a non-negative
+** arguments or differing preferred text encodings.  ^SQLite will use
+** the implementation that most closely matches the way in which the
+** SQL function is used.  ^A function implementation with a non-negative
 ** nArg parameter is a better match than a function implementation with
-** a negative nArg.  A function where the preferred text encoding
+** a negative nArg.  ^A function where the preferred text encoding
 ** matches the database encoding is a better
 ** match than a function where the encoding is different.  
-** A function where the encoding difference is between UTF16le and UTF16be
+** ^A function where the encoding difference is between UTF16le and UTF16be
 ** is a closer match than a function where the encoding difference is
 ** between UTF8 and UTF16.
 **
-** Built-in functions may be overloaded by new application-defined functions.
-** The first application-defined function with a given name overrides all
-** built-in functions in the same [database connection] with the same name.
-** Subsequent application-defined functions of the same name only override 
-** prior application-defined functions that are an exact match for the
-** number of parameters and preferred encoding.
+** ^Built-in functions may be overloaded by new application-defined functions.
 **
-** An application-defined function is permitted to call other
+** ^An application-defined function is permitted to call other
 ** SQLite interfaces.  However, such calls must not
 ** close the database connection nor finalize or reset the prepared
 ** statement in which the function is running.
-**
-** INVARIANTS:
-**
-** {H16103} The [sqlite3_create_function16(D,X,...)] interface shall behave
-**          as [sqlite3_create_function(D,X,...)] in every way except that it
-**          interprets the X argument as zero-terminated UTF-16
-**          native byte order instead of as zero-terminated UTF-8.
-**
-** {H16106} A successful invocation of the
-**          [sqlite3_create_function(D,X,N,E,...)] interface shall register
-**          or replaces callback functions in the [database connection] D
-**          used to implement the SQL function named X with N parameters
-**          and having a preferred text encoding of E.
-**
-** {H16109} A successful call to [sqlite3_create_function(D,X,N,E,P,F,S,L)]
-**          shall replace the P, F, S, and L values from any prior calls with
-**          the same D, X, N, and E values.
-**
-** {H16112} The [sqlite3_create_function(D,X,...)] interface shall fail
-**          if the SQL function name X is
-**          longer than 255 bytes exclusive of the zero terminator.
-**
-** {H16118} The [sqlite3_create_function(D,X,N,E,P,F,S,L)] interface
-**          shall fail unless either F is NULL and S and L are non-NULL or
-***         F is non-NULL and S and L are NULL.
-**
-** {H16121} The [sqlite3_create_function(D,...)] interface shall fails with an
-**          error code of [SQLITE_BUSY] if there exist [prepared statements]
-**          associated with the [database connection] D.
-**
-** {H16124} The [sqlite3_create_function(D,X,N,...)] interface shall fail with
-**          an error code of [SQLITE_ERROR] if parameter N is less
-**          than -1 or greater than 127.
-**
-** {H16127} When N is non-negative, the [sqlite3_create_function(D,X,N,...)]
-**          interface shall register callbacks to be invoked for the
-**          SQL function
-**          named X when the number of arguments to the SQL function is
-**          exactly N.
-**
-** {H16130} When N is -1, the [sqlite3_create_function(D,X,N,...)]
-**          interface shall register callbacks to be invoked for the SQL
-**          function named X with any number of arguments.
-**
-** {H16133} When calls to [sqlite3_create_function(D,X,N,...)]
-**          specify multiple implementations of the same function X
-**          and when one implementation has N>=0 and the other has N=(-1)
-**          the implementation with a non-zero N shall be preferred.
-**
-** {H16136} When calls to [sqlite3_create_function(D,X,N,E,...)]
-**          specify multiple implementations of the same function X with
-**          the same number of arguments N but with different
-**          encodings E, then the implementation where E matches the
-**          database encoding shall preferred.
-**
-** {H16139} For an aggregate SQL function created using
-**          [sqlite3_create_function(D,X,N,E,P,0,S,L)] the finalizer
-**          function L shall always be invoked exactly once if the
-**          step function S is called one or more times.
-**
-** {H16142} When SQLite invokes either the xFunc or xStep function of
-**          an application-defined SQL function or aggregate created
-**          by [sqlite3_create_function()] or [sqlite3_create_function16()],
-**          then the array of [sqlite3_value] objects passed as the
-**          third parameter shall be [protected sqlite3_value] objects.
 */
 SQLITE_API int sqlite3_create_function(
   sqlite3 *db,
@@ -4655,9 +4453,20 @@ SQLITE_API int sqlite3_create_function16(
   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
   void (*xFinal)(sqlite3_context*)
 );
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void(*xDestroy)(void*)
+);
 
 /*
-** CAPI3REF: Text Encodings {H10267} <S50200> <H16100>
+** CAPI3REF: Text Encodings
 **
 ** These constant define integer codes that represent the various
 ** text encodings supported by SQLite.
@@ -4689,7 +4498,7 @@ SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int6
 #endif
 
 /*
-** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200>
+** CAPI3REF: Obtaining SQL Function Parameter Values
 **
 ** The C-language implementation of SQL functions and aggregates uses
 ** this set of interface routines to access the parameter values on
@@ -4698,7 +4507,7 @@ SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int6
 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
 ** define callbacks that implement the SQL functions and aggregates.
-** The 4th parameter to these callbacks is an array of pointers to
+** The 3rd parameter to these callbacks is an array of pointers to
 ** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
 ** each parameter to the SQL function.  These routines are used to
 ** extract values from the [sqlite3_value] objects.
@@ -4707,22 +4516,22 @@ SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int6
 ** Any attempt to use these routines on an [unprotected sqlite3_value]
 ** object results in undefined behavior.
 **
-** These routines work just like the corresponding [column access functions]
+** ^These routines work just like the corresponding [column access functions]
 ** except that  these routines take a single [protected sqlite3_value] object
 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
 **
-** The sqlite3_value_text16() interface extracts a UTF-16 string
-** in the native byte-order of the host machine.  The
+** ^The sqlite3_value_text16() interface extracts a UTF-16 string
+** in the native byte-order of the host machine.  ^The
 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
 ** extract UTF-16 strings as big-endian and little-endian respectively.
 **
-** The sqlite3_value_numeric_type() interface attempts to apply
+** ^(The sqlite3_value_numeric_type() interface attempts to apply
 ** numeric affinity to the value.  This means that an attempt is
 ** made to convert the value to an integer or floating point.  If
 ** such a conversion is possible without loss of information (in other
 ** words, if the value is a string that looks like a number)
 ** then the conversion is performed.  Otherwise no conversion occurs.
-** The [SQLITE_INTEGER | datatype] after conversion is returned.
+** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
 **
 ** Please pay particular attention to the fact that the pointer returned
 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
@@ -4732,68 +4541,6 @@ SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int6
 **
 ** These routines must be called from the same thread as
 ** the SQL function that supplied the [sqlite3_value*] parameters.
-**
-** INVARIANTS:
-**
-** {H15103} The [sqlite3_value_blob(V)] interface converts the
-**          [protected sqlite3_value] object V into a BLOB and then
-**          returns a pointer to the converted value.
-**
-** {H15106} The [sqlite3_value_bytes(V)] interface returns the
-**          number of bytes in the BLOB or string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_value_blob(V)] or
-**          [sqlite3_value_text(V)].
-**
-** {H15109} The [sqlite3_value_bytes16(V)] interface returns the
-**          number of bytes in the string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_value_text16(V)],
-**          [sqlite3_value_text16be(V)], or [sqlite3_value_text16le(V)].
-**
-** {H15112} The [sqlite3_value_double(V)] interface converts the
-**          [protected sqlite3_value] object V into a floating point value and
-**          returns a copy of that value.
-**
-** {H15115} The [sqlite3_value_int(V)] interface converts the
-**          [protected sqlite3_value] object V into a 64-bit signed integer and
-**          returns the lower 32 bits of that integer.
-**
-** {H15118} The [sqlite3_value_int64(V)] interface converts the
-**          [protected sqlite3_value] object V into a 64-bit signed integer and
-**          returns a copy of that integer.
-**
-** {H15121} The [sqlite3_value_text(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated UTF-8
-**          string and returns a pointer to that string.
-**
-** {H15124} The [sqlite3_value_text16(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated 2-byte
-**          aligned UTF-16 native byte order
-**          string and returns a pointer to that string.
-**
-** {H15127} The [sqlite3_value_text16be(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated 2-byte
-**          aligned UTF-16 big-endian
-**          string and returns a pointer to that string.
-**
-** {H15130} The [sqlite3_value_text16le(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated 2-byte
-**          aligned UTF-16 little-endian
-**          string and returns a pointer to that string.
-**
-** {H15133} The [sqlite3_value_type(V)] interface returns
-**          one of [SQLITE_NULL], [SQLITE_INTEGER], [SQLITE_FLOAT],
-**          [SQLITE_TEXT], or [SQLITE_BLOB] as appropriate for
-**          the [sqlite3_value] object V.
-**
-** {H15136} The [sqlite3_value_numeric_type(V)] interface converts
-**          the [protected sqlite3_value] object V into either an integer or
-**          a floating point value if it can do so without loss of
-**          information, and returns one of [SQLITE_NULL],
-**          [SQLITE_INTEGER], [SQLITE_FLOAT], [SQLITE_TEXT], or
-**          [SQLITE_BLOB] as appropriate for the
-**          [protected sqlite3_value] object V after the conversion attempt.
 */
 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
@@ -4809,91 +4556,73 @@ SQLITE_API int sqlite3_value_type(sqlite3_value*);
 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
 
 /*
-** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200>
+** CAPI3REF: Obtain Aggregate Function Context
 **
-** The implementation of aggregate SQL functions use this routine to allocate
-** a structure for storing their state.
+** Implementations of aggregate SQL functions use this
+** routine to allocate memory for storing their state.
 **
-** The first time the sqlite3_aggregate_context() routine is called for a
-** particular aggregate, SQLite allocates nBytes of memory, zeroes out that
-** memory, and returns a pointer to it. On second and subsequent calls to
-** sqlite3_aggregate_context() for the same aggregate function index,
-** the same buffer is returned. The implementation of the aggregate can use
-** the returned buffer to accumulate data.
+** ^The first time the sqlite3_aggregate_context(C,N) routine is called 
+** for a particular aggregate function, SQLite
+** allocates N of memory, zeroes out that memory, and returns a pointer
+** to the new memory. ^On second and subsequent calls to
+** sqlite3_aggregate_context() for the same aggregate function instance,
+** the same buffer is returned.  Sqlite3_aggregate_context() is normally
+** called once for each invocation of the xStep callback and then one
+** last time when the xFinal callback is invoked.  ^(When no rows match
+** an aggregate query, the xStep() callback of the aggregate function
+** implementation is never called and xFinal() is called exactly once.
+** In those cases, sqlite3_aggregate_context() might be called for the
+** first time from within xFinal().)^
 **
-** SQLite automatically frees the allocated buffer when the aggregate
-** query concludes.
+** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
+** less than or equal to zero or if a memory allocate error occurs.
 **
-** The first parameter should be a copy of the
+** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
+** determined by the N parameter on first successful call.  Changing the
+** value of N in subsequent call to sqlite3_aggregate_context() within
+** the same aggregate function instance will not resize the memory
+** allocation.)^
+**
+** ^SQLite automatically frees the memory allocated by 
+** sqlite3_aggregate_context() when the aggregate query concludes.
+**
+** The first parameter must be a copy of the
 ** [sqlite3_context | SQL function context] that is the first parameter
-** to the callback routine that implements the aggregate function.
+** to the xStep or xFinal callback routine that implements the aggregate
+** function.
 **
 ** This routine must be called from the same thread in which
 ** the aggregate SQL function is running.
-**
-** INVARIANTS:
-**
-** {H16211} The first invocation of [sqlite3_aggregate_context(C,N)] for
-**          a particular instance of an aggregate function (for a particular
-**          context C) causes SQLite to allocate N bytes of memory,
-**          zero that memory, and return a pointer to the allocated memory.
-**
-** {H16213} If a memory allocation error occurs during
-**          [sqlite3_aggregate_context(C,N)] then the function returns 0.
-**
-** {H16215} Second and subsequent invocations of
-**          [sqlite3_aggregate_context(C,N)] for the same context pointer C
-**          ignore the N parameter and return a pointer to the same
-**          block of memory returned by the first invocation.
-**
-** {H16217} The memory allocated by [sqlite3_aggregate_context(C,N)] is
-**          automatically freed on the next call to [sqlite3_reset()]
-**          or [sqlite3_finalize()] for the [prepared statement] containing
-**          the aggregate function associated with context C.
 */
 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
 
 /*
-** CAPI3REF: User Data For Functions {H16240} <S20200>
+** CAPI3REF: User Data For Functions
 **
-** The sqlite3_user_data() interface returns a copy of
+** ^The sqlite3_user_data() interface returns a copy of
 ** the pointer that was the pUserData parameter (the 5th parameter)
 ** of the [sqlite3_create_function()]
 ** and [sqlite3_create_function16()] routines that originally
-** registered the application defined function. {END}
-**
-** This routine must be called from the same thread in which
-** the application-defined function is running.
-**
-** INVARIANTS:
-**
-** {H16243} The [sqlite3_user_data(C)] interface returns a copy of the
-**          P pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]
-**          or [sqlite3_create_function16(D,X,N,E,P,F,S,L)] call that
-**          registered the SQL function associated with [sqlite3_context] C.
-*/
-SQLITE_API void *sqlite3_user_data(sqlite3_context*);
-
-/*
-** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200>
-**
-** The sqlite3_context_db_handle() interface returns a copy of
-** the pointer to the [database connection] (the 1st parameter)
-** of the [sqlite3_create_function()]
-** and [sqlite3_create_function16()] routines that originally
 ** registered the application defined function.
 **
-** INVARIANTS:
+** This routine must be called from the same thread in which
+** the application-defined function is running.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context*);
+
+/*
+** CAPI3REF: Database Connection For Functions
 **
-** {H16253} The [sqlite3_context_db_handle(C)] interface returns a copy of the
-**          D pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]
-**          or [sqlite3_create_function16(D,X,N,E,P,F,S,L)] call that
-**          registered the SQL function associated with [sqlite3_context] C.
+** ^The sqlite3_context_db_handle() interface returns a copy of
+** the pointer to the [database connection] (the 1st parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
 */
 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
 
 /*
-** CAPI3REF: Function Auxiliary Data {H16270} <S20200>
+** CAPI3REF: Function Auxiliary Data
 **
 ** The following two functions may be used by scalar SQL functions to
 ** associate metadata with argument values. If the same value is passed to
@@ -4906,71 +4635,45 @@ SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
 ** invocations of the same function so that the original pattern string
 ** does not need to be recompiled on each invocation.
 **
-** The sqlite3_get_auxdata() interface returns a pointer to the metadata
+** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
 ** associated by the sqlite3_set_auxdata() function with the Nth argument
-** value to the application-defined function. If no metadata has been ever
+** value to the application-defined function. ^If no metadata has been ever
 ** been set for the Nth argument of the function, or if the corresponding
 ** function parameter has changed since the meta-data was set,
 ** then sqlite3_get_auxdata() returns a NULL pointer.
 **
-** The sqlite3_set_auxdata() interface saves the metadata
+** ^The sqlite3_set_auxdata() interface saves the metadata
 ** pointed to by its 3rd parameter as the metadata for the N-th
 ** argument of the application-defined function.  Subsequent
 ** calls to sqlite3_get_auxdata() might return this data, if it has
 ** not been destroyed.
-** If it is not NULL, SQLite will invoke the destructor
+** ^If it is not NULL, SQLite will invoke the destructor
 ** function given by the 4th parameter to sqlite3_set_auxdata() on
 ** the metadata when the corresponding function parameter changes
 ** or when the SQL statement completes, whichever comes first.
 **
 ** SQLite is free to call the destructor and drop metadata on any
-** parameter of any function at any time.  The only guarantee is that
+** parameter of any function at any time.  ^The only guarantee is that
 ** the destructor will be called before the metadata is dropped.
 **
-** In practice, metadata is preserved between function calls for
+** ^(In practice, metadata is preserved between function calls for
 ** expressions that are constant at compile time. This includes literal
-** values and SQL variables.
+** values and [parameters].)^
 **
 ** These routines must be called from the same thread in which
 ** the SQL function is running.
-**
-** INVARIANTS:
-**
-** {H16272} The [sqlite3_get_auxdata(C,N)] interface returns a pointer
-**          to metadata associated with the Nth parameter of the SQL function
-**          whose context is C, or NULL if there is no metadata associated
-**          with that parameter.
-**
-** {H16274} The [sqlite3_set_auxdata(C,N,P,D)] interface assigns a metadata
-**          pointer P to the Nth parameter of the SQL function with context C.
-**
-** {H16276} SQLite will invoke the destructor D with a single argument
-**          which is the metadata pointer P following a call to
-**          [sqlite3_set_auxdata(C,N,P,D)] when SQLite ceases to hold
-**          the metadata.
-**
-** {H16277} SQLite ceases to hold metadata for an SQL function parameter
-**          when the value of that parameter changes.
-**
-** {H16278} When [sqlite3_set_auxdata(C,N,P,D)] is invoked, the destructor
-**          is called for any prior metadata associated with the same function
-**          context C and parameter N.
-**
-** {H16279} SQLite will call destructors for any metadata it is holding
-**          in a particular [prepared statement] S when either
-**          [sqlite3_reset(S)] or [sqlite3_finalize(S)] is called.
 */
 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
 
 
 /*
-** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100>
+** CAPI3REF: Constants Defining Special Destructor Behavior
 **
 ** These are special values for the destructor that is passed in as the
-** final argument to routines like [sqlite3_result_blob()].  If the destructor
+** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
 ** argument is SQLITE_STATIC, it means that the content pointer is constant
-** and will never change.  It does not need to be destroyed.  The
+** and will never change.  It does not need to be destroyed.  ^The
 ** SQLITE_TRANSIENT value means that the content will likely change in
 ** the near future and that SQLite should make its own private copy of
 ** the content before returning.
@@ -4983,7 +4686,7 @@ typedef void (*sqlite3_destructor_type)(void*);
 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
 
 /*
-** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200>
+** CAPI3REF: Setting The Result Of An SQL Function
 **
 ** These routines are used by the xFunc or xFinal callbacks that
 ** implement SQL functions and aggregates.  See
@@ -4994,193 +4697,103 @@ typedef void (*sqlite3_destructor_type)(void*);
 ** functions used to bind values to host parameters in prepared statements.
 ** Refer to the [SQL parameter] documentation for additional information.
 **
-** The sqlite3_result_blob() interface sets the result from
+** ^The sqlite3_result_blob() interface sets the result from
 ** an application-defined function to be the BLOB whose content is pointed
 ** to by the second parameter and which is N bytes long where N is the
 ** third parameter.
 **
-** The sqlite3_result_zeroblob() interfaces set the result of
+** ^The sqlite3_result_zeroblob() interfaces set the result of
 ** the application-defined function to be a BLOB containing all zero
 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
 **
-** The sqlite3_result_double() interface sets the result from
+** ^The sqlite3_result_double() interface sets the result from
 ** an application-defined function to be a floating point value specified
 ** by its 2nd argument.
 **
-** The sqlite3_result_error() and sqlite3_result_error16() functions
+** ^The sqlite3_result_error() and sqlite3_result_error16() functions
 ** cause the implemented SQL function to throw an exception.
-** SQLite uses the string pointed to by the
+** ^SQLite uses the string pointed to by the
 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
-** as the text of an error message.  SQLite interprets the error
-** message string from sqlite3_result_error() as UTF-8. SQLite
+** as the text of an error message.  ^SQLite interprets the error
+** message string from sqlite3_result_error() as UTF-8. ^SQLite
 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
-** byte order.  If the third parameter to sqlite3_result_error()
+** byte order.  ^If the third parameter to sqlite3_result_error()
 ** or sqlite3_result_error16() is negative then SQLite takes as the error
 ** message all text up through the first zero character.
-** If the third parameter to sqlite3_result_error() or
+** ^If the third parameter to sqlite3_result_error() or
 ** sqlite3_result_error16() is non-negative then SQLite takes that many
 ** bytes (not characters) from the 2nd parameter as the error message.
-** The sqlite3_result_error() and sqlite3_result_error16()
+** ^The sqlite3_result_error() and sqlite3_result_error16()
 ** routines make a private copy of the error message text before
 ** they return.  Hence, the calling function can deallocate or
 ** modify the text after they return without harm.
-** The sqlite3_result_error_code() function changes the error code
-** returned by SQLite as a result of an error in a function.  By default,
-** the error code is SQLITE_ERROR.  A subsequent call to sqlite3_result_error()
+** ^The sqlite3_result_error_code() function changes the error code
+** returned by SQLite as a result of an error in a function.  ^By default,
+** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
 **
-** The sqlite3_result_toobig() interface causes SQLite to throw an error
-** indicating that a string or BLOB is to long to represent.
+** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
+** error indicating that a string or BLOB is too long to represent.
 **
-** The sqlite3_result_nomem() interface causes SQLite to throw an error
-** indicating that a memory allocation failed.
+** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
+** error indicating that a memory allocation failed.
 **
-** The sqlite3_result_int() interface sets the return value
+** ^The sqlite3_result_int() interface sets the return value
 ** of the application-defined function to be the 32-bit signed integer
 ** value given in the 2nd argument.
-** The sqlite3_result_int64() interface sets the return value
+** ^The sqlite3_result_int64() interface sets the return value
 ** of the application-defined function to be the 64-bit signed integer
 ** value given in the 2nd argument.
 **
-** The sqlite3_result_null() interface sets the return value
+** ^The sqlite3_result_null() interface sets the return value
 ** of the application-defined function to be NULL.
 **
-** The sqlite3_result_text(), sqlite3_result_text16(),
+** ^The sqlite3_result_text(), sqlite3_result_text16(),
 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
 ** set the return value of the application-defined function to be
 ** a text string which is represented as UTF-8, UTF-16 native byte order,
 ** UTF-16 little endian, or UTF-16 big endian, respectively.
-** SQLite takes the text result from the application from
+** ^SQLite takes the text result from the application from
 ** the 2nd parameter of the sqlite3_result_text* interfaces.
-** If the 3rd parameter to the sqlite3_result_text* interfaces
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 ** is negative, then SQLite takes result text from the 2nd parameter
 ** through the first zero character.
-** If the 3rd parameter to the sqlite3_result_text* interfaces
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 ** is non-negative, then as many bytes (not characters) of the text
 ** pointed to by the 2nd parameter are taken as the application-defined
-** function result.
-** If the 4th parameter to the sqlite3_result_text* interfaces
+** function result.  If the 3rd parameter is non-negative, then it
+** must be the byte offset into the string where the NUL terminator would
+** appear if the string where NUL terminated.  If any NUL characters occur
+** in the string at a byte offset that is less than the value of the 3rd
+** parameter, then the resulting string will contain embedded NULs and the
+** result of expressions operating on strings with embedded NULs is undefined.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
 ** function as the destructor on the text or BLOB result when it has
 ** finished using that result.
-** If the 4th parameter to the sqlite3_result_text* interfaces or
+** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
 ** assumes that the text or BLOB result is in constant space and does not
-** copy the it or call a destructor when it has finished using that result.
-** If the 4th parameter to the sqlite3_result_text* interfaces
+** copy the content of the parameter nor call a destructor on the content
+** when it has finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
 ** then SQLite makes a copy of the result into space obtained from
 ** from [sqlite3_malloc()] before it returns.
 **
-** The sqlite3_result_value() interface sets the result of
+** ^The sqlite3_result_value() interface sets the result of
 ** the application-defined function to be a copy the
-** [unprotected sqlite3_value] object specified by the 2nd parameter.  The
+** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
 ** so that the [sqlite3_value] specified in the parameter may change or
 ** be deallocated after sqlite3_result_value() returns without harm.
-** A [protected sqlite3_value] object may always be used where an
+** ^A [protected sqlite3_value] object may always be used where an
 ** [unprotected sqlite3_value] object is required, so either
 ** kind of [sqlite3_value] object can be used with this interface.
 **
 ** If these routines are called from within the different thread
 ** than the one containing the application-defined function that received
 ** the [sqlite3_context] pointer, the results are undefined.
-**
-** INVARIANTS:
-**
-** {H16403} The default return value from any SQL function is NULL.
-**
-** {H16406} The [sqlite3_result_blob(C,V,N,D)] interface changes the
-**          return value of function C to be a BLOB that is N bytes
-**          in length and with content pointed to by V.
-**
-** {H16409} The [sqlite3_result_double(C,V)] interface changes the
-**          return value of function C to be the floating point value V.
-**
-** {H16412} The [sqlite3_result_error(C,V,N)] interface changes the return
-**          value of function C to be an exception with error code
-**          [SQLITE_ERROR] and a UTF-8 error message copied from V up to the
-**          first zero byte or until N bytes are read if N is positive.
-**
-** {H16415} The [sqlite3_result_error16(C,V,N)] interface changes the return
-**          value of function C to be an exception with error code
-**          [SQLITE_ERROR] and a UTF-16 native byte order error message
-**          copied from V up to the first zero terminator or until N bytes
-**          are read if N is positive.
-**
-** {H16418} The [sqlite3_result_error_toobig(C)] interface changes the return
-**          value of the function C to be an exception with error code
-**          [SQLITE_TOOBIG] and an appropriate error message.
-**
-** {H16421} The [sqlite3_result_error_nomem(C)] interface changes the return
-**          value of the function C to be an exception with error code
-**          [SQLITE_NOMEM] and an appropriate error message.
-**
-** {H16424} The [sqlite3_result_error_code(C,E)] interface changes the return
-**          value of the function C to be an exception with error code E.
-**          The error message text is unchanged.
-**
-** {H16427} The [sqlite3_result_int(C,V)] interface changes the
-**          return value of function C to be the 32-bit integer value V.
-**
-** {H16430} The [sqlite3_result_int64(C,V)] interface changes the
-**          return value of function C to be the 64-bit integer value V.
-**
-** {H16433} The [sqlite3_result_null(C)] interface changes the
-**          return value of function C to be NULL.
-**
-** {H16436} The [sqlite3_result_text(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-8 string
-**          V up to the first zero if N is negative
-**          or the first N bytes of V if N is non-negative.
-**
-** {H16439} The [sqlite3_result_text16(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-16 native byte order
-**          string V up to the first zero if N is negative
-**          or the first N bytes of V if N is non-negative.
-**
-** {H16442} The [sqlite3_result_text16be(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-16 big-endian
-**          string V up to the first zero if N is negative
-**          or the first N bytes or V if N is non-negative.
-**
-** {H16445} The [sqlite3_result_text16le(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-16 little-endian
-**          string V up to the first zero if N is negative
-**          or the first N bytes of V if N is non-negative.
-**
-** {H16448} The [sqlite3_result_value(C,V)] interface changes the
-**          return value of function C to be the [unprotected sqlite3_value]
-**          object V.
-**
-** {H16451} The [sqlite3_result_zeroblob(C,N)] interface changes the
-**          return value of function C to be an N-byte BLOB of all zeros.
-**
-** {H16454} The [sqlite3_result_error()] and [sqlite3_result_error16()]
-**          interfaces make a copy of their error message strings before
-**          returning.
-**
-** {H16457} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
-**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
-**          [sqlite3_result_text16be(C,V,N,D)], or
-**          [sqlite3_result_text16le(C,V,N,D)] is the constant [SQLITE_STATIC]
-**          then no destructor is ever called on the pointer V and SQLite
-**          assumes that V is immutable.
-**
-** {H16460} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
-**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
-**          [sqlite3_result_text16be(C,V,N,D)], or
-**          [sqlite3_result_text16le(C,V,N,D)] is the constant
-**          [SQLITE_TRANSIENT] then the interfaces makes a copy of the
-**          content of V and retains the copy.
-**
-** {H16463} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
-**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
-**          [sqlite3_result_text16be(C,V,N,D)], or
-**          [sqlite3_result_text16le(C,V,N,D)] is some value other than
-**          the constants [SQLITE_STATIC] and [SQLITE_TRANSIENT] then
-**          SQLite will invoke the destructor D with V as its only argument
-**          when it has finished with the V value.
 */
 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
@@ -5200,108 +4813,96 @@ SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
 
 /*
-** CAPI3REF: Define New Collating Sequences {H16600} <S20300>
+** CAPI3REF: Define New Collating Sequences
 **
-** These functions are used to add new collation sequences to the
-** [database connection] specified as the first argument.
+** ^These functions add, remove, or modify a [collation] associated
+** with the [database connection] specified as the first argument.
 **
-** The name of the new collation sequence is specified as a UTF-8 string
+** ^The name of the collation is a UTF-8 string
 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
-** and a UTF-16 string for sqlite3_create_collation16(). In all cases
-** the name is passed as the second function argument.
+** and a UTF-16 string in native byte order for sqlite3_create_collation16().
+** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
+** considered to be the same name.
 **
-** The third argument may be one of the constants [SQLITE_UTF8],
-** [SQLITE_UTF16LE] or [SQLITE_UTF16BE], indicating that the user-supplied
-** routine expects to be passed pointers to strings encoded using UTF-8,
-** UTF-16 little-endian, or UTF-16 big-endian, respectively. The
-** third argument might also be [SQLITE_UTF16_ALIGNED] to indicate that
-** the routine expects pointers to 16-bit word aligned strings
-** of UTF-16 in the native byte order of the host computer.
+** ^(The third argument (eTextRep) must be one of the constants:
+** <ul>
+** <li> [SQLITE_UTF8],
+** <li> [SQLITE_UTF16LE],
+** <li> [SQLITE_UTF16BE],
+** <li> [SQLITE_UTF16], or
+** <li> [SQLITE_UTF16_ALIGNED].
+** </ul>)^
+** ^The eTextRep argument determines the encoding of strings passed
+** to the collating function callback, xCallback.
+** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
+** force strings to be UTF16 with native byte order.
+** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
+** on an even byte address.
 **
-** A pointer to the user supplied routine must be passed as the fifth
-** argument.  If it is NULL, this is the same as deleting the collation
-** sequence (so that SQLite cannot call it anymore).
-** Each time the application supplied function is invoked, it is passed
-** as its first parameter a copy of the void* passed as the fourth argument
-** to sqlite3_create_collation() or sqlite3_create_collation16().
+** ^The fourth argument, pArg, is an application data pointer that is passed
+** through as the first argument to the collating function callback.
 **
-** The remaining arguments to the application-supplied routine are two strings,
-** each represented by a (length, data) pair and encoded in the encoding
-** that was passed as the third argument when the collation sequence was
-** registered. {END}  The application defined collation routine should
-** return negative, zero or positive if the first string is less than,
-** equal to, or greater than the second string. i.e. (STRING1 - STRING2).
+** ^The fifth argument, xCallback, is a pointer to the collating function.
+** ^Multiple collating functions can be registered using the same name but
+** with different eTextRep parameters and SQLite will use whichever
+** function requires the least amount of data transformation.
+** ^If the xCallback argument is NULL then the collating function is
+** deleted.  ^When all collating functions having the same name are deleted,
+** that collation is no longer usable.
 **
-** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
-** except that it takes an extra argument which is a destructor for
-** the collation.  The destructor is called when the collation is
-** destroyed and is passed a copy of the fourth parameter void* pointer
-** of the sqlite3_create_collation_v2().
-** Collations are destroyed when they are overridden by later calls to the
-** collation creation functions or when the [database connection] is closed
-** using [sqlite3_close()].
+** ^The collating function callback is invoked with a copy of the pArg 
+** application data pointer and with two strings in the encoding specified
+** by the eTextRep argument.  The collating function must return an
+** integer that is negative, zero, or positive
+** if the first string is less than, equal to, or greater than the second,
+** respectively.  A collating function must always return the same answer
+** given the same inputs.  If two or more collating functions are registered
+** to the same collation name (using different eTextRep values) then all
+** must give an equivalent answer when invoked with equivalent strings.
+** The collating function must obey the following properties for all
+** strings A, B, and C:
 **
-** INVARIANTS:
+** <ol>
+** <li> If A==B then B==A.
+** <li> If A==B and B==C then A==C.
+** <li> If A&lt;B THEN B&gt;A.
+** <li> If A&lt;B and B&lt;C then A&lt;C.
+** </ol>
 **
-** {H16603} A successful call to the
-**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] interface
-**          registers function F as the comparison function used to
-**          implement collation X on the [database connection] B for
-**          databases having encoding E.
+** If a collating function fails any of the above constraints and that
+** collating function is  registered and used, then the behavior of SQLite
+** is undefined.
 **
-** {H16604} SQLite understands the X parameter to
-**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] as a zero-terminated
-**          UTF-8 string in which case is ignored for ASCII characters and
-**          is significant for non-ASCII characters.
+** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
+** with the addition that the xDestroy callback is invoked on pArg when
+** the collating function is deleted.
+** ^Collating functions are deleted when they are overridden by later
+** calls to the collation creation functions or when the
+** [database connection] is closed using [sqlite3_close()].
 **
-** {H16606} Successive calls to [sqlite3_create_collation_v2(B,X,E,P,F,D)]
-**          with the same values for B, X, and E, override prior values
-**          of P, F, and D.
+** ^The xDestroy callback is <u>not</u> called if the 
+** sqlite3_create_collation_v2() function fails.  Applications that invoke
+** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 
+** check the return code and dispose of the application data pointer
+** themselves rather than expecting SQLite to deal with it for them.
+** This is different from every other SQLite interface.  The inconsistency 
+** is unfortunate but cannot be changed without breaking backwards 
+** compatibility.
 **
-** {H16609} If the destructor D in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
-**          is not NULL then it is called with argument P when the
-**          collating function is dropped by SQLite.
-**
-** {H16612} A collating function is dropped when it is overloaded.
-**
-** {H16615} A collating function is dropped when the database connection
-**          is closed using [sqlite3_close()].
-**
-** {H16618} The pointer P in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
-**          is passed through as the first parameter to the comparison
-**          function F for all subsequent invocations of F.
-**
-** {H16621} A call to [sqlite3_create_collation(B,X,E,P,F)] is exactly
-**          the same as a call to [sqlite3_create_collation_v2()] with
-**          the same parameters and a NULL destructor.
-**
-** {H16624} Following a [sqlite3_create_collation_v2(B,X,E,P,F,D)],
-**          SQLite uses the comparison function F for all text comparison
-**          operations on the [database connection] B on text values that
-**          use the collating sequence named X.
-**
-** {H16627} The [sqlite3_create_collation16(B,X,E,P,F)] works the same
-**          as [sqlite3_create_collation(B,X,E,P,F)] except that the
-**          collation name X is understood as UTF-16 in native byte order
-**          instead of UTF-8.
-**
-** {H16630} When multiple comparison functions are available for the same
-**          collating sequence, SQLite chooses the one whose text encoding
-**          requires the least amount of conversion from the default
-**          text encoding of the database.
+** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
 */
 SQLITE_API int sqlite3_create_collation(
   sqlite3*, 
   const char *zName, 
   int eTextRep, 
-  void*,
+  void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*)
 );
 SQLITE_API int sqlite3_create_collation_v2(
   sqlite3*, 
   const char *zName, 
   int eTextRep, 
-  void*,
+  void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*),
   void(*xDestroy)(void*)
 );
@@ -5309,54 +4910,35 @@ SQLITE_API int sqlite3_create_collation16(
   sqlite3*, 
   const void *zName,
   int eTextRep, 
-  void*,
+  void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*)
 );
 
 /*
-** CAPI3REF: Collation Needed Callbacks {H16700} <S20300>
+** CAPI3REF: Collation Needed Callbacks
 **
-** To avoid having to register all collation sequences before a database
+** ^To avoid having to register all collation sequences before a database
 ** can be used, a single callback function may be registered with the
-** [database connection] to be called whenever an undefined collation
+** [database connection] to be invoked whenever an undefined collation
 ** sequence is required.
 **
-** If the function is registered using the sqlite3_collation_needed() API,
+** ^If the function is registered using the sqlite3_collation_needed() API,
 ** then it is passed the names of undefined collation sequences as strings
-** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used,
+** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
 ** the names are passed as UTF-16 in machine native byte order.
-** A call to either function replaces any existing callback.
+** ^A call to either function replaces the existing collation-needed callback.
 **
-** When the callback is invoked, the first argument passed is a copy
+** ^(When the callback is invoked, the first argument passed is a copy
 ** of the second argument to sqlite3_collation_needed() or
 ** sqlite3_collation_needed16().  The second argument is the database
 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
 ** sequence function required.  The fourth parameter is the name of the
-** required collation sequence.
+** required collation sequence.)^
 **
 ** The callback function should register the desired collation using
 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
 ** [sqlite3_create_collation_v2()].
-**
-** INVARIANTS:
-**
-** {H16702} A successful call to [sqlite3_collation_needed(D,P,F)]
-**          or [sqlite3_collation_needed16(D,P,F)] causes
-**          the [database connection] D to invoke callback F with first
-**          parameter P whenever it needs a comparison function for a
-**          collating sequence that it does not know about.
-**
-** {H16704} Each successful call to [sqlite3_collation_needed()] or
-**          [sqlite3_collation_needed16()] overrides the callback registered
-**          on the same [database connection] by prior calls to either
-**          interface.
-**
-** {H16706} The name of the requested collating function passed in the
-**          4th parameter to the callback is in UTF-8 if the callback
-**          was registered using [sqlite3_collation_needed()] and
-**          is in UTF-16 native byte order if the callback was
-**          registered using [sqlite3_collation_needed16()].
 */
 SQLITE_API int sqlite3_collation_needed(
   sqlite3*, 
@@ -5369,6 +4951,7 @@ SQLITE_API int sqlite3_collation_needed16(
   void(*)(void*,sqlite3*,int eTextRep,const void*)
 );
 
+#ifdef SQLITE_HAS_CODEC
 /*
 ** Specify the key for an encrypted database.  This routine should be
 ** called right after sqlite3_open().
@@ -5395,7 +4978,26 @@ SQLITE_API int sqlite3_rekey(
 );
 
 /*
-** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410>
+** Specify the activation key for a SEE database.  Unless 
+** activated, none of the SEE routines will work.
+*/
+SQLITE_API void sqlite3_activate_see(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+#ifdef SQLITE_ENABLE_CEROD
+/*
+** Specify the activation key for a CEROD database.  Unless 
+** activated, none of the CEROD routines will work.
+*/
+SQLITE_API void sqlite3_activate_cerod(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+/*
+** CAPI3REF: Suspend Execution For A Short Time
 **
 ** The sqlite3_sleep() function causes the current thread to suspend execution
 ** for at least a number of milliseconds specified in its parameter.
@@ -5405,47 +5007,106 @@ SQLITE_API int sqlite3_rekey(
 ** the nearest second. The number of milliseconds of sleep actually
 ** requested from the operating system is returned.
 **
-** SQLite implements this interface by calling the xSleep()
-** method of the default [sqlite3_vfs] object.
-**
-** INVARIANTS:
-**
-** {H10533} The [sqlite3_sleep(M)] interface invokes the xSleep
-**          method of the default [sqlite3_vfs|VFS] in order to
-**          suspend execution of the current thread for at least
-**          M milliseconds.
-**
-** {H10536} The [sqlite3_sleep(M)] interface returns the number of
-**          milliseconds of sleep actually requested of the operating
-**          system, which might be larger than the parameter M.
+** ^SQLite implements this interface by calling the xSleep()
+** method of the default [sqlite3_vfs] object.  If the xSleep() method
+** of the default VFS is not implemented correctly, or not implemented at
+** all, then the behavior of sqlite3_sleep() may deviate from the description
+** in the previous paragraphs.
 */
 SQLITE_API int sqlite3_sleep(int);
 
 /*
-** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000>
+** CAPI3REF: Name Of The Folder Holding Temporary Files
 **
-** If this global variable is made to point to a string which is
+** ^(If this global variable is made to point to a string which is
 ** the name of a folder (a.k.a. directory), then all temporary files
-** created by SQLite will be placed in that directory.  If this variable
+** created by SQLite when using a built-in [sqlite3_vfs | VFS]
+** will be placed in that directory.)^  ^If this variable
 ** is a NULL pointer, then SQLite performs a search for an appropriate
 ** temporary file directory.
 **
-** It is not safe to modify this variable once a [database connection]
-** has been opened.  It is intended that this variable be set once
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
 ** as part of process initialization and before any SQLite interface
-** routines have been call and remain unchanged thereafter.
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [temp_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [temp_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from 
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [temp_store_directory pragma] should be avoided.
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
+** features that require the use of temporary files may fail.  Here is an
+** example of how to do this using C++ with the Windows Runtime:
+**
+** <blockquote><pre>
+** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
+** &nbsp;     TemporaryFolder->Path->Data();
+** char zPathBuf&#91;MAX_PATH + 1&#93;;
+** memset(zPathBuf, 0, sizeof(zPathBuf));
+** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
+** &nbsp;     NULL, NULL);
+** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
+** </pre></blockquote>
 */
 SQLITE_API char *sqlite3_temp_directory;
 
 /*
-** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200>
+** CAPI3REF: Name Of The Folder Holding Database Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all database files
+** specified with a relative pathname and created or accessed by
+** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
+** to be relative to that directory.)^ ^If this variable is a NULL
+** pointer, then SQLite assumes that all database files specified
+** with a relative pathname are relative to the current directory
+** for the process.  Only the windows VFS makes use of this global
+** variable; it is ignored by the unix VFS.
+**
+** Changing the value of this variable while a database connection is
+** open can result in a corrupt database.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [data_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [data_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from 
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [data_store_directory pragma] should be avoided.
+*/
+SQLITE_API char *sqlite3_data_directory;
+
+/*
+** CAPI3REF: Test For Auto-Commit Mode
 ** KEYWORDS: {autocommit mode}
 **
-** The sqlite3_get_autocommit() interface returns non-zero or
+** ^The sqlite3_get_autocommit() interface returns non-zero or
 ** zero if the given database connection is or is not in autocommit mode,
-** respectively.  Autocommit mode is on by default.
-** Autocommit mode is disabled by a [BEGIN] statement.
-** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
+** respectively.  ^Autocommit mode is on by default.
+** ^Autocommit mode is disabled by a [BEGIN] statement.
+** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
 **
 ** If certain kinds of errors occur on a statement within a multi-statement
 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
@@ -5454,180 +5115,143 @@ SQLITE_API char *sqlite3_temp_directory;
 ** find out whether SQLite automatically rolled back the transaction after
 ** an error is to use this function.
 **
-** INVARIANTS:
-**
-** {H12931} The [sqlite3_get_autocommit(D)] interface returns non-zero or
-**          zero if the [database connection] D is or is not in autocommit
-**          mode, respectively.
-**
-** {H12932} Autocommit mode is on by default.
-**
-** {H12933} Autocommit mode is disabled by a successful [BEGIN] statement.
-**
-** {H12934} Autocommit mode is enabled by a successful [COMMIT] or [ROLLBACK]
-**          statement.
-**
-** ASSUMPTIONS:
-**
-** {A12936} If another thread changes the autocommit status of the database
-**          connection while this routine is running, then the return value
-**          is undefined.
+** If another thread changes the autocommit status of the database
+** connection while this routine is running, then the return value
+** is undefined.
 */
 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
 
 /*
-** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600>
+** CAPI3REF: Find The Database Handle Of A Prepared Statement
 **
-** The sqlite3_db_handle interface returns the [database connection] handle
-** to which a [prepared statement] belongs.  The database handle returned by
-** sqlite3_db_handle is the same database handle that was the first argument
+** ^The sqlite3_db_handle interface returns the [database connection] handle
+** to which a [prepared statement] belongs.  ^The [database connection]
+** returned by sqlite3_db_handle is the same [database connection]
+** that was the first argument
 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
 ** create the statement in the first place.
-**
-** INVARIANTS:
-**
-** {H13123} The [sqlite3_db_handle(S)] interface returns a pointer
-**          to the [database connection] associated with the
-**          [prepared statement] S.
 */
 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Find the next prepared statement {H13140} <S60600>
+** CAPI3REF: Return The Filename For A Database Connection
 **
-** This interface returns a pointer to the next [prepared statement] after
-** pStmt associated with the [database connection] pDb.  If pStmt is NULL
+** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
+** associated with database N of connection D.  ^The main database file
+** has the name "main".  If there is no attached database N on the database
+** connection D, or if database N is a temporary or in-memory database, then
+** a NULL pointer is returned.
+**
+** ^The filename returned by this function is the output of the
+** xFullPathname method of the [VFS].  ^In other words, the filename
+** will be an absolute pathname, even if the filename used
+** to open the database originally was a URI or relative pathname.
+*/
+SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine if a database is read-only
+**
+** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
+** of connection D is read-only, 0 if it is read/write, or -1 if N is not
+** the name of a database on connection D.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Find the next prepared statement
+**
+** ^This interface returns a pointer to the next [prepared statement] after
+** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
 ** then this interface returns a pointer to the first prepared statement
-** associated with the database connection pDb.  If no prepared statement
+** associated with the database connection pDb.  ^If no prepared statement
 ** satisfies the conditions of this routine, it returns NULL.
 **
-** INVARIANTS:
-**
-** {H13143} If D is a [database connection] that holds one or more
-**          unfinalized [prepared statements] and S is a NULL pointer,
-**          then [sqlite3_next_stmt(D, S)] routine shall return a pointer
-**          to one of the prepared statements associated with D.
-**
-** {H13146} If D is a [database connection] that holds no unfinalized
-**          [prepared statements] and S is a NULL pointer, then
-**          [sqlite3_next_stmt(D, S)] routine shall return a NULL pointer.
-**
-** {H13149} If S is a [prepared statement] in the [database connection] D
-**          and S is not the last prepared statement in D, then
-**          [sqlite3_next_stmt(D, S)] routine shall return a pointer
-**          to the next prepared statement in D after S.
-**
-** {H13152} If S is the last [prepared statement] in the
-**          [database connection] D then the [sqlite3_next_stmt(D, S)]
-**          routine shall return a NULL pointer.
-**
-** ASSUMPTIONS:
-**
-** {A13154} The [database connection] pointer D in a call to
-**          [sqlite3_next_stmt(D,S)] must refer to an open database
-**          connection and in particular must not be a NULL pointer.
+** The [database connection] pointer D in a call to
+** [sqlite3_next_stmt(D,S)] must refer to an open database
+** connection and in particular must not be a NULL pointer.
 */
 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400>
+** CAPI3REF: Commit And Rollback Notification Callbacks
 **
-** The sqlite3_commit_hook() interface registers a callback
-** function to be invoked whenever a transaction is committed.
-** Any callback set by a previous call to sqlite3_commit_hook()
+** ^The sqlite3_commit_hook() interface registers a callback
+** function to be invoked whenever a transaction is [COMMIT | committed].
+** ^Any callback set by a previous call to sqlite3_commit_hook()
 ** for the same database connection is overridden.
-** The sqlite3_rollback_hook() interface registers a callback
-** function to be invoked whenever a transaction is committed.
-** Any callback set by a previous call to sqlite3_commit_hook()
+** ^The sqlite3_rollback_hook() interface registers a callback
+** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
+** ^Any callback set by a previous call to sqlite3_rollback_hook()
 ** for the same database connection is overridden.
-** The pArg argument is passed through to the callback.
-** If the callback on a commit hook function returns non-zero,
+** ^The pArg argument is passed through to the callback.
+** ^If the callback on a commit hook function returns non-zero,
 ** then the commit is converted into a rollback.
 **
-** If another function was previously registered, its
-** pArg value is returned.  Otherwise NULL is returned.
+** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
+** return the P argument from the previous call of the same function
+** on the same [database connection] D, or NULL for
+** the first call for each function on D.
 **
+** The commit and rollback hook callbacks are not reentrant.
 ** The callback implementation must not do anything that will modify
 ** the database connection that invoked the callback.  Any actions
 ** to modify the database connection must be deferred until after the
 ** completion of the [sqlite3_step()] call that triggered the commit
 ** or rollback hook in the first place.
-** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
-** database connections for the meaning of "modify" in this paragraph.
+** Note that running any other SQL statements, including SELECT statements,
+** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
+** the database connections for the meaning of "modify" in this paragraph.
 **
-** Registering a NULL function disables the callback.
+** ^Registering a NULL function disables the callback.
 **
-** For the purposes of this API, a transaction is said to have been
+** ^When the commit hook callback routine returns zero, the [COMMIT]
+** operation is allowed to continue normally.  ^If the commit hook
+** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
+** ^The rollback hook is invoked on a rollback that results from a commit
+** hook returning non-zero, just as it would be with any other rollback.
+**
+** ^For the purposes of this API, a transaction is said to have been
 ** rolled back if an explicit "ROLLBACK" statement is executed, or
 ** an error or constraint causes an implicit rollback to occur.
-** The rollback callback is not invoked if a transaction is
+** ^The rollback callback is not invoked if a transaction is
 ** automatically rolled back because the database connection is closed.
-** The rollback callback is not invoked if a transaction is
-** rolled back because a commit callback returned non-zero.
-** <todo> Check on this </todo>
 **
-** INVARIANTS:
-**
-** {H12951} The [sqlite3_commit_hook(D,F,P)] interface registers the
-**          callback function F to be invoked with argument P whenever
-**          a transaction commits on the [database connection] D.
-**
-** {H12952} The [sqlite3_commit_hook(D,F,P)] interface returns the P argument
-**          from the previous call with the same [database connection] D,
-**          or NULL on the first call for a particular database connection D.
-**
-** {H12953} Each call to [sqlite3_commit_hook()] overwrites the callback
-**          registered by prior calls.
-**
-** {H12954} If the F argument to [sqlite3_commit_hook(D,F,P)] is NULL
-**          then the commit hook callback is canceled and no callback
-**          is invoked when a transaction commits.
-**
-** {H12955} If the commit callback returns non-zero then the commit is
-**          converted into a rollback.
-**
-** {H12961} The [sqlite3_rollback_hook(D,F,P)] interface registers the
-**          callback function F to be invoked with argument P whenever
-**          a transaction rolls back on the [database connection] D.
-**
-** {H12962} The [sqlite3_rollback_hook(D,F,P)] interface returns the P
-**          argument from the previous call with the same
-**          [database connection] D, or NULL on the first call
-**          for a particular database connection D.
-**
-** {H12963} Each call to [sqlite3_rollback_hook()] overwrites the callback
-**          registered by prior calls.
-**
-** {H12964} If the F argument to [sqlite3_rollback_hook(D,F,P)] is NULL
-**          then the rollback hook callback is canceled and no callback
-**          is invoked when a transaction rolls back.
+** See also the [sqlite3_update_hook()] interface.
 */
 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
 
 /*
-** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400>
+** CAPI3REF: Data Change Notification Callbacks
 **
-** The sqlite3_update_hook() interface registers a callback function
+** ^The sqlite3_update_hook() interface registers a callback function
 ** with the [database connection] identified by the first argument
 ** to be invoked whenever a row is updated, inserted or deleted.
-** Any callback set by a previous call to this function
+** ^Any callback set by a previous call to this function
 ** for the same database connection is overridden.
 **
-** The second argument is a pointer to the function to invoke when a
+** ^The second argument is a pointer to the function to invoke when a
 ** row is updated, inserted or deleted.
-** The first argument to the callback is a copy of the third argument
+** ^The first argument to the callback is a copy of the third argument
 ** to sqlite3_update_hook().
-** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
+** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
 ** to be invoked.
-** The third and fourth arguments to the callback contain pointers to the
+** ^The third and fourth arguments to the callback contain pointers to the
 ** database and table name containing the affected row.
-** The final callback parameter is the [rowid] of the row.
-** In the case of an update, this is the [rowid] after the update takes place.
+** ^The final callback parameter is the [rowid] of the row.
+** ^In the case of an update, this is the [rowid] after the update takes place.
 **
-** The update hook is not invoked when internal system tables are
-** modified (i.e. sqlite_master and sqlite_sequence).
+** ^(The update hook is not invoked when internal system tables are
+** modified (i.e. sqlite_master and sqlite_sequence).)^
+**
+** ^In the current implementation, the update hook
+** is not invoked when duplication rows are deleted because of an
+** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
+** invoked when rows are deleted using the [truncate optimization].
+** The exceptions defined in this paragraph might change in a future
+** release of SQLite.
 **
 ** The update hook implementation must not do anything that will modify
 ** the database connection that invoked the update hook.  Any actions
@@ -5636,39 +5260,13 @@ SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
-** If another function was previously registered, its pArg value
-** is returned.  Otherwise NULL is returned.
+** ^The sqlite3_update_hook(D,C,P) function
+** returns the P argument from the previous call
+** on the same [database connection] D, or NULL for
+** the first call on D.
 **
-** INVARIANTS:
-**
-** {H12971} The [sqlite3_update_hook(D,F,P)] interface causes the callback
-**          function F to be invoked with first parameter P whenever
-**          a table row is modified, inserted, or deleted on
-**          the [database connection] D.
-**
-** {H12973} The [sqlite3_update_hook(D,F,P)] interface returns the value
-**          of P for the previous call on the same [database connection] D,
-**          or NULL for the first call.
-**
-** {H12975} If the update hook callback F in [sqlite3_update_hook(D,F,P)]
-**          is NULL then the no update callbacks are made.
-**
-** {H12977} Each call to [sqlite3_update_hook(D,F,P)] overrides prior calls
-**          to the same interface on the same [database connection] D.
-**
-** {H12979} The update hook callback is not invoked when internal system
-**          tables such as sqlite_master and sqlite_sequence are modified.
-**
-** {H12981} The second parameter to the update callback
-**          is one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
-**          depending on the operation that caused the callback to be invoked.
-**
-** {H12983} The third and fourth arguments to the callback contain pointers
-**          to zero-terminated UTF-8 strings which are the names of the
-**          database and table that is being updated.
-
-** {H12985} The final callback parameter is the [rowid] of the row after
-**          the change occurs.
+** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
+** interfaces.
 */
 SQLITE_API void *sqlite3_update_hook(
   sqlite3*, 
@@ -5677,155 +5275,149 @@ SQLITE_API void *sqlite3_update_hook(
 );
 
 /*
-** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900>
-** KEYWORDS: {shared cache} {shared cache mode}
+** CAPI3REF: Enable Or Disable Shared Pager Cache
 **
-** This routine enables or disables the sharing of the database cache
+** ^(This routine enables or disables the sharing of the database cache
 ** and schema data structures between [database connection | connections]
 ** to the same database. Sharing is enabled if the argument is true
-** and disabled if the argument is false.
+** and disabled if the argument is false.)^
 **
-** Cache sharing is enabled and disabled for an entire process. {END}
+** ^Cache sharing is enabled and disabled for an entire process.
 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
 ** sharing was enabled or disabled for each thread separately.
 **
-** The cache sharing mode set by this interface effects all subsequent
+** ^(The cache sharing mode set by this interface effects all subsequent
 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
 ** Existing database connections continue use the sharing mode
-** that was in effect at the time they were opened.
+** that was in effect at the time they were opened.)^
 **
-** Virtual tables cannot be used with a shared cache.  When shared
-** cache is enabled, the [sqlite3_create_module()] API used to register
-** virtual tables will always return an error.
+** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
+** successfully.  An [error code] is returned otherwise.)^
 **
-** This routine returns [SQLITE_OK] if shared cache was enabled or disabled
-** successfully.  An [error code] is returned otherwise.
-**
-** Shared cache is disabled by default. But this might change in
+** ^Shared cache is disabled by default. But this might change in
 ** future releases of SQLite.  Applications that care about shared
 ** cache setting should set it explicitly.
 **
-** INVARIANTS:
-**
-** {H10331} A successful invocation of [sqlite3_enable_shared_cache(B)]
-**          will enable or disable shared cache mode for any subsequently
-**          created [database connection] in the same process.
-**
-** {H10336} When shared cache is enabled, the [sqlite3_create_module()]
-**          interface will always return an error.
-**
-** {H10337} The [sqlite3_enable_shared_cache(B)] interface returns
-**          [SQLITE_OK] if shared cache was enabled or disabled successfully.
-**
-** {H10339} Shared cache is disabled by default.
+** See Also:  [SQLite Shared-Cache Mode]
 */
 SQLITE_API int sqlite3_enable_shared_cache(int);
 
 /*
-** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220>
+** CAPI3REF: Attempt To Free Heap Memory
 **
-** The sqlite3_release_memory() interface attempts to free N bytes
+** ^The sqlite3_release_memory() interface attempts to free N bytes
 ** of heap memory by deallocating non-essential memory allocations
-** held by the database library. {END}  Memory used to cache database
+** held by the database library.   Memory used to cache database
 ** pages to improve performance is an example of non-essential memory.
-** sqlite3_release_memory() returns the number of bytes actually freed,
+** ^sqlite3_release_memory() returns the number of bytes actually freed,
 ** which might be more or less than the amount requested.
+** ^The sqlite3_release_memory() routine is a no-op returning zero
+** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
 **
-** INVARIANTS:
-**
-** {H17341} The [sqlite3_release_memory(N)] interface attempts to
-**          free N bytes of heap memory by deallocating non-essential
-**          memory allocations held by the database library.
-**
-** {H16342} The [sqlite3_release_memory(N)] returns the number
-**          of bytes actually freed, which might be more or less
-**          than the amount requested.
+** See also: [sqlite3_db_release_memory()]
 */
 SQLITE_API int sqlite3_release_memory(int);
 
 /*
-** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220>
+** CAPI3REF: Free Memory Used By A Database Connection
 **
-** The sqlite3_soft_heap_limit() interface places a "soft" limit
-** on the amount of heap memory that may be allocated by SQLite.
-** If an internal allocation is requested that would exceed the
-** soft heap limit, [sqlite3_release_memory()] is invoked one or
-** more times to free up some space before the allocation is performed.
+** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
+** memory as possible from database connection D. Unlike the
+** [sqlite3_release_memory()] interface, this interface is effect even
+** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
+** omitted.
 **
-** The limit is called "soft", because if [sqlite3_release_memory()]
-** cannot free sufficient memory to prevent the limit from being exceeded,
-** the memory is allocated anyway and the current operation proceeds.
-**
-** A negative or zero value for N means that there is no soft heap limit and
-** [sqlite3_release_memory()] will only be called when memory is exhausted.
-** The default value for the soft heap limit is zero.
-**
-** SQLite makes a best effort to honor the soft heap limit.
-** But if the soft heap limit cannot be honored, execution will
-** continue without error or notification.  This is why the limit is
-** called a "soft" limit.  It is advisory only.
-**
-** Prior to SQLite version 3.5.0, this routine only constrained the memory
-** allocated by a single thread - the same thread in which this routine
-** runs.  Beginning with SQLite version 3.5.0, the soft heap limit is
-** applied to all threads. The value specified for the soft heap limit
-** is an upper bound on the total memory allocation for all threads. In
-** version 3.5.0 there is no mechanism for limiting the heap usage for
-** individual threads.
-**
-** INVARIANTS:
-**
-** {H16351} The [sqlite3_soft_heap_limit(N)] interface places a soft limit
-**          of N bytes on the amount of heap memory that may be allocated
-**          using [sqlite3_malloc()] or [sqlite3_realloc()] at any point
-**          in time.
-**
-** {H16352} If a call to [sqlite3_malloc()] or [sqlite3_realloc()] would
-**          cause the total amount of allocated memory to exceed the
-**          soft heap limit, then [sqlite3_release_memory()] is invoked
-**          in an attempt to reduce the memory usage prior to proceeding
-**          with the memory allocation attempt.
-**
-** {H16353} Calls to [sqlite3_malloc()] or [sqlite3_realloc()] that trigger
-**          attempts to reduce memory usage through the soft heap limit
-**          mechanism continue even if the attempt to reduce memory
-**          usage is unsuccessful.
-**
-** {H16354} A negative or zero value for N in a call to
-**          [sqlite3_soft_heap_limit(N)] means that there is no soft
-**          heap limit and [sqlite3_release_memory()] will only be
-**          called when memory is completely exhausted.
-**
-** {H16355} The default value for the soft heap limit is zero.
-**
-** {H16358} Each call to [sqlite3_soft_heap_limit(N)] overrides the
-**          values set by all prior calls.
+** See also: [sqlite3_release_memory()]
 */
-SQLITE_API void sqlite3_soft_heap_limit(int);
+SQLITE_API int sqlite3_db_release_memory(sqlite3*);
 
 /*
-** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300>
+** CAPI3REF: Impose A Limit On Heap Size
 **
-** This routine returns metadata about a specific column of a specific
+** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
+** soft limit on the amount of heap memory that may be allocated by SQLite.
+** ^SQLite strives to keep heap memory utilization below the soft heap
+** limit by reducing the number of pages held in the page cache
+** as heap memory usages approaches the limit.
+** ^The soft heap limit is "soft" because even though SQLite strives to stay
+** below the limit, it will exceed the limit rather than generate
+** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
+** is advisory only.
+**
+** ^The return value from sqlite3_soft_heap_limit64() is the size of
+** the soft heap limit prior to the call, or negative in the case of an
+** error.  ^If the argument N is negative
+** then no change is made to the soft heap limit.  Hence, the current
+** size of the soft heap limit can be determined by invoking
+** sqlite3_soft_heap_limit64() with a negative argument.
+**
+** ^If the argument N is zero then the soft heap limit is disabled.
+**
+** ^(The soft heap limit is not enforced in the current implementation
+** if one or more of following conditions are true:
+**
+** <ul>
+** <li> The soft heap limit is set to zero.
+** <li> Memory accounting is disabled using a combination of the
+**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
+**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
+** <li> An alternative page cache implementation is specified using
+**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
+** <li> The page cache allocates from its own memory pool supplied
+**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
+**      from the heap.
+** </ul>)^
+**
+** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
+** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
+** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
+** the soft heap limit is enforced on every memory allocation.  Without
+** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
+** when memory is allocated by the page cache.  Testing suggests that because
+** the page cache is the predominate memory user in SQLite, most
+** applications will achieve adequate soft heap limit enforcement without
+** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
+**
+** The circumstances under which SQLite will enforce the soft heap limit may
+** changes in future releases of SQLite.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
+
+/*
+** CAPI3REF: Deprecated Soft Heap Limit Interface
+** DEPRECATED
+**
+** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
+** interface.  This routine is provided for historical compatibility
+** only.  All new applications should use the
+** [sqlite3_soft_heap_limit64()] interface rather than this one.
+*/
+SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
+
+
+/*
+** CAPI3REF: Extract Metadata About A Column Of A Table
+**
+** ^This routine returns metadata about a specific column of a specific
 ** database table accessible using the [database connection] handle
 ** passed as the first function argument.
 **
-** The column is identified by the second, third and fourth parameters to
-** this function. The second parameter is either the name of the database
-** (i.e. "main", "temp" or an attached database) containing the specified
-** table or NULL. If it is NULL, then all attached databases are searched
+** ^The column is identified by the second, third and fourth parameters to
+** this function. ^The second parameter is either the name of the database
+** (i.e. "main", "temp", or an attached database) containing the specified
+** table or NULL. ^If it is NULL, then all attached databases are searched
 ** for the table using the same algorithm used by the database engine to
 ** resolve unqualified table references.
 **
-** The third and fourth parameters to this function are the table and column
+** ^The third and fourth parameters to this function are the table and column
 ** name of the desired column, respectively. Neither of these parameters
 ** may be NULL.
 **
-** Metadata is returned by writing to the memory locations passed as the 5th
-** and subsequent parameters to this function. Any of these arguments may be
+** ^Metadata is returned by writing to the memory locations passed as the 5th
+** and subsequent parameters to this function. ^Any of these arguments may be
 ** NULL, in which case the corresponding element of metadata is omitted.
 **
-** <blockquote>
+** ^(<blockquote>
 ** <table border="1">
 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
 **
@@ -5835,17 +5427,17 @@ SQLITE_API void sqlite3_soft_heap_limit(int);
 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
 ** </table>
-** </blockquote>
+** </blockquote>)^
 **
-** The memory pointed to by the character pointers returned for the
+** ^The memory pointed to by the character pointers returned for the
 ** declaration type and collation sequence is valid only until the next
 ** call to any SQLite API function.
 **
-** If the specified table is actually a view, an [error code] is returned.
+** ^If the specified table is actually a view, an [error code] is returned.
 **
-** If the specified column is "rowid", "oid" or "_rowid_" and an
+** ^If the specified column is "rowid", "oid" or "_rowid_" and an
 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
-** parameters are set for the explicitly declared column. If there is no
+** parameters are set for the explicitly declared column. ^(If there is no
 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
 ** parameters are set as follows:
 **
@@ -5855,14 +5447,14 @@ SQLITE_API void sqlite3_soft_heap_limit(int);
 **     not null: 0
 **     primary key: 1
 **     auto increment: 0
-** </pre>
+** </pre>)^
 **
-** This function may load one or more schemas from database files. If an
+** ^(This function may load one or more schemas from database files. If an
 ** error occurs during this process, or if the requested table or column
 ** cannot be found, an [error code] is returned and an error message left
-** in the [database connection] (to be retrieved using sqlite3_errmsg()).
+** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
 **
-** This API is only available if the library was compiled with the
+** ^This API is only available if the library was compiled with the
 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
 */
 SQLITE_API int sqlite3_table_column_metadata(
@@ -5878,30 +5470,29 @@ SQLITE_API int sqlite3_table_column_metadata(
 );
 
 /*
-** CAPI3REF: Load An Extension {H12600} <S20500>
+** CAPI3REF: Load An Extension
 **
-** This interface loads an SQLite extension library from the named file.
+** ^This interface loads an SQLite extension library from the named file.
 **
-** {H12601} The sqlite3_load_extension() interface attempts to load an
-**          SQLite extension library contained in the file zFile.
+** ^The sqlite3_load_extension() interface attempts to load an
+** SQLite extension library contained in the file zFile.
 **
-** {H12602} The entry point is zProc.
+** ^The entry point is zProc.
+** ^zProc may be 0, in which case the name of the entry point
+** defaults to "sqlite3_extension_init".
+** ^The sqlite3_load_extension() interface returns
+** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
+** ^If an error occurs and pzErrMsg is not 0, then the
+** [sqlite3_load_extension()] interface shall attempt to
+** fill *pzErrMsg with error message text stored in memory
+** obtained from [sqlite3_malloc()]. The calling function
+** should free this memory by calling [sqlite3_free()].
 **
-** {H12603} zProc may be 0, in which case the name of the entry point
-**          defaults to "sqlite3_extension_init".
+** ^Extension loading must be enabled using
+** [sqlite3_enable_load_extension()] prior to calling this API,
+** otherwise an error will be returned.
 **
-** {H12604} The sqlite3_load_extension() interface shall return
-**          [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
-**
-** {H12605} If an error occurs and pzErrMsg is not 0, then the
-**          [sqlite3_load_extension()] interface shall attempt to
-**          fill *pzErrMsg with error message text stored in memory
-**          obtained from [sqlite3_malloc()]. {END}  The calling function
-**          should free this memory by calling [sqlite3_free()].
-**
-** {H12606} Extension loading must be enabled using
-**          [sqlite3_enable_load_extension()] prior to calling this API,
-**          otherwise an error will be returned.
+** See also the [load_extension() SQL function].
 */
 SQLITE_API int sqlite3_load_extension(
   sqlite3 *db,          /* Load the extension into this database connection */
@@ -5911,67 +5502,66 @@ SQLITE_API int sqlite3_load_extension(
 );
 
 /*
-** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500>
+** CAPI3REF: Enable Or Disable Extension Loading
 **
-** So as not to open security holes in older applications that are
+** ^So as not to open security holes in older applications that are
 ** unprepared to deal with extension loading, and as a means of disabling
 ** extension loading while evaluating user-entered SQL, the following API
 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
 **
-** Extension loading is off by default. See ticket #1863.
-**
-** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1
-**          to turn extension loading on and call it with onoff==0 to turn
-**          it back off again.
-**
-** {H12622} Extension loading is off by default.
+** ^Extension loading is off by default. See ticket #1863.
+** ^Call the sqlite3_enable_load_extension() routine with onoff==1
+** to turn extension loading on and call it with onoff==0 to turn
+** it back off again.
 */
 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
 
 /*
-** CAPI3REF: Automatically Load An Extensions {H12640} <S20500>
+** CAPI3REF: Automatically Load Statically Linked Extensions
 **
-** This API can be invoked at program startup in order to register
-** one or more statically linked extensions that will be available
-** to all new [database connections]. {END}
+** ^This interface causes the xEntryPoint() function to be invoked for
+** each new [database connection] that is created.  The idea here is that
+** xEntryPoint() is the entry point for a statically linked SQLite extension
+** that is to be automatically loaded into all new database connections.
 **
-** This routine stores a pointer to the extension in an array that is
-** obtained from [sqlite3_malloc()].  If you run a memory leak checker
-** on your program and it reports a leak because of this array, invoke
-** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory.
+** ^(Even though the function prototype shows that xEntryPoint() takes
+** no arguments and returns void, SQLite invokes xEntryPoint() with three
+** arguments and expects and integer result as if the signature of the
+** entry point where as follows:
 **
-** {H12641} This function registers an extension entry point that is
-**          automatically invoked whenever a new [database connection]
-**          is opened using [sqlite3_open()], [sqlite3_open16()],
-**          or [sqlite3_open_v2()].
+** <blockquote><pre>
+** &nbsp;  int xEntryPoint(
+** &nbsp;    sqlite3 *db,
+** &nbsp;    const char **pzErrMsg,
+** &nbsp;    const struct sqlite3_api_routines *pThunk
+** &nbsp;  );
+** </pre></blockquote>)^
 **
-** {H12642} Duplicate extensions are detected so calling this routine
-**          multiple times with the same extension is harmless.
+** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
+** point to an appropriate error message (obtained from [sqlite3_mprintf()])
+** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
+** is NULL before calling the xEntryPoint().  ^SQLite will invoke
+** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
+** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
+** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
 **
-** {H12643} This routine stores a pointer to the extension in an array
-**          that is obtained from [sqlite3_malloc()].
+** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
+** on the list of automatic extensions is a harmless no-op. ^No entry point
+** will be called more than once for each database connection that is opened.
 **
-** {H12644} Automatic extensions apply across all threads.
+** See also: [sqlite3_reset_auto_extension()].
 */
 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
 
 /*
-** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500>
+** CAPI3REF: Reset Automatic Extension Loading
 **
-** This function disables all previously registered automatic
-** extensions. {END}  It undoes the effect of all prior
-** [sqlite3_auto_extension()] calls.
-**
-** {H12661} This function disables all previously registered
-**          automatic extensions.
-**
-** {H12662} This function disables automatic extensions in all threads.
+** ^This interface disables all automatic extensions previously
+** registered using [sqlite3_auto_extension()].
 */
 SQLITE_API void sqlite3_reset_auto_extension(void);
 
 /*
-****** EXPERIMENTAL - subject to change without notice **************
-**
 ** The interface to the virtual-table mechanism is currently considered
 ** to be experimental.  The interface might change in incompatible ways.
 ** If this is a problem for you, do not use the interface at this time.
@@ -5989,16 +5579,20 @@ typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
 typedef struct sqlite3_module sqlite3_module;
 
 /*
-** CAPI3REF: Virtual Table Object {H18000} <S20400>
-** KEYWORDS: sqlite3_module
-** EXPERIMENTAL
+** CAPI3REF: Virtual Table Object
+** KEYWORDS: sqlite3_module {virtual table module}
 **
-** A module is a class of virtual tables.  Each module is defined
-** by an instance of the following structure.  This structure consists
-** mostly of methods for the module.
+** This structure, sometimes called a "virtual table module", 
+** defines the implementation of a [virtual tables].  
+** This structure consists mostly of methods for the module.
 **
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
+** ^A virtual table module is created by filling in a persistent
+** instance of this structure and passing a pointer to that instance
+** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
+** ^The registration remains valid until it is replaced by a different
+** module or until the [database connection] closes.  The content
+** of this structure must not change while it is registered with
+** any database connection.
 */
 struct sqlite3_module {
   int iVersion;
@@ -6028,59 +5622,65 @@ struct sqlite3_module {
                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
                        void **ppArg);
   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
+  /* The methods above are in version 1 of the sqlite_module object. Those 
+  ** below are for version 2 and greater. */
+  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
+  int (*xRelease)(sqlite3_vtab *pVTab, int);
+  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
 };
 
 /*
-** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400>
+** CAPI3REF: Virtual Table Indexing Information
 ** KEYWORDS: sqlite3_index_info
-** EXPERIMENTAL
 **
-** The sqlite3_index_info structure and its substructures is used to
-** pass information into and receive the reply from the xBestIndex
-** method of an sqlite3_module.  The fields under **Inputs** are the
+** The sqlite3_index_info structure and its substructures is used as part
+** of the [virtual table] interface to
+** pass information into and receive the reply from the [xBestIndex]
+** method of a [virtual table module].  The fields under **Inputs** are the
 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
 ** results into the **Outputs** fields.
 **
-** The aConstraint[] array records WHERE clause constraints of the form:
+** ^(The aConstraint[] array records WHERE clause constraints of the form:
 **
-** <pre>column OP expr</pre>
+** <blockquote>column OP expr</blockquote>
 **
-** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.  The particular operator is
-** stored in aConstraint[].op.  The index of the column is stored in
-** aConstraint[].iColumn.  aConstraint[].usable is TRUE if the
+** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
+** stored in aConstraint[].op using one of the
+** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
+** ^(The index of the column is stored in
+** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
 ** expr on the right-hand side can be evaluated (and thus the constraint
-** is usable) and false if it cannot.
+** is usable) and false if it cannot.)^
 **
-** The optimizer automatically inverts terms of the form "expr OP column"
+** ^The optimizer automatically inverts terms of the form "expr OP column"
 ** and makes other simplifications to the WHERE clause in an attempt to
 ** get as many WHERE clause terms into the form shown above as possible.
-** The aConstraint[] array only reports WHERE clause terms in the correct
-** form that refer to the particular virtual table being queried.
+** ^The aConstraint[] array only reports WHERE clause terms that are
+** relevant to the particular virtual table being queried.
 **
-** Information about the ORDER BY clause is stored in aOrderBy[].
-** Each term of aOrderBy records a column of the ORDER BY clause.
+** ^Information about the ORDER BY clause is stored in aOrderBy[].
+** ^Each term of aOrderBy records a column of the ORDER BY clause.
 **
-** The xBestIndex method must fill aConstraintUsage[] with information
-** about what parameters to pass to xFilter.  If argvIndex>0 then
+** The [xBestIndex] method must fill aConstraintUsage[] with information
+** about what parameters to pass to xFilter.  ^If argvIndex>0 then
 ** the right-hand side of the corresponding aConstraint[] is evaluated
-** and becomes the argvIndex-th entry in argv.  If aConstraintUsage[].omit
+** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
 ** is true, then the constraint is assumed to be fully handled by the
-** virtual table and is not checked again by SQLite.
+** virtual table and is not checked again by SQLite.)^
 **
-** The idxNum and idxPtr values are recorded and passed into xFilter.
-** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true.
+** ^The idxNum and idxPtr values are recorded and passed into the
+** [xFilter] method.
+** ^[sqlite3_free()] is used to free idxPtr if and only if
+** needToFreeIdxPtr is true.
 **
-** The orderByConsumed means that output from xFilter will occur in
+** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
 ** the correct order to satisfy the ORDER BY clause so that no separate
 ** sorting step is required.
 **
-** The estimatedCost value is an estimate of the cost of doing the
+** ^The estimatedCost value is an estimate of the cost of doing the
 ** particular lookup.  A full scan of a table with N entries should have
 ** a cost of N.  A binary search of a table of N entries should have a
 ** cost of approximately log(N).
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
 */
 struct sqlite3_index_info {
   /* Inputs */
@@ -6107,6 +5707,15 @@ struct sqlite3_index_info {
   int orderByConsumed;       /* True if output is already ordered */
   double estimatedCost;      /* Estimated cost of using this index */
 };
+
+/*
+** CAPI3REF: Virtual Table Constraint Operator Codes
+**
+** These macros defined the allowed values for the
+** [sqlite3_index_info].aConstraint[].op field.  Each value represents
+** an operator that is part of a constraint term in the wHERE clause of
+** a query that uses a [virtual table].
+*/
 #define SQLITE_INDEX_CONSTRAINT_EQ    2
 #define SQLITE_INDEX_CONSTRAINT_GT    4
 #define SQLITE_INDEX_CONSTRAINT_LE    8
@@ -6115,87 +5724,85 @@ struct sqlite3_index_info {
 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
 
 /*
-** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400>
-** EXPERIMENTAL
+** CAPI3REF: Register A Virtual Table Implementation
 **
-** This routine is used to register a new module name with a
-** [database connection].  Module names must be registered before
-** creating new virtual tables on the module, or before using
-** preexisting virtual tables of the module.
+** ^These routines are used to register a new [virtual table module] name.
+** ^Module names must be registered before
+** creating a new [virtual table] using the module and before using a
+** preexisting [virtual table] for the module.
 **
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
+** ^The module name is registered on the [database connection] specified
+** by the first parameter.  ^The name of the module is given by the 
+** second parameter.  ^The third parameter is a pointer to
+** the implementation of the [virtual table module].   ^The fourth
+** parameter is an arbitrary client data pointer that is passed through
+** into the [xCreate] and [xConnect] methods of the virtual table module
+** when a new virtual table is be being created or reinitialized.
+**
+** ^The sqlite3_create_module_v2() interface has a fifth parameter which
+** is a pointer to a destructor for the pClientData.  ^SQLite will
+** invoke the destructor function (if it is not NULL) when SQLite
+** no longer needs the pClientData pointer.  ^The destructor will also
+** be invoked if the call to sqlite3_create_module_v2() fails.
+** ^The sqlite3_create_module()
+** interface is equivalent to sqlite3_create_module_v2() with a NULL
+** destructor.
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module(
+SQLITE_API int sqlite3_create_module(
   sqlite3 *db,               /* SQLite connection to register module with */
   const char *zName,         /* Name of the module */
-  const sqlite3_module *,    /* Methods for the module */
-  void *                     /* Client data for xCreate/xConnect */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData          /* Client data for xCreate/xConnect */
 );
-
-/*
-** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400>
-** EXPERIMENTAL
-**
-** This routine is identical to the [sqlite3_create_module()] method above,
-** except that it allows a destructor function to be specified. It is
-** even more experimental than the rest of the virtual tables API.
-*/
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module_v2(
+SQLITE_API int sqlite3_create_module_v2(
   sqlite3 *db,               /* SQLite connection to register module with */
   const char *zName,         /* Name of the module */
-  const sqlite3_module *,    /* Methods for the module */
-  void *,                    /* Client data for xCreate/xConnect */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData,         /* Client data for xCreate/xConnect */
   void(*xDestroy)(void*)     /* Module destructor function */
 );
 
 /*
-** CAPI3REF: Virtual Table Instance Object {H18010} <S20400>
+** CAPI3REF: Virtual Table Instance Object
 ** KEYWORDS: sqlite3_vtab
-** EXPERIMENTAL
 **
-** Every module implementation uses a subclass of the following structure
-** to describe a particular instance of the module.  Each subclass will
+** Every [virtual table module] implementation uses a subclass
+** of this object to describe a particular instance
+** of the [virtual table].  Each subclass will
 ** be tailored to the specific needs of the module implementation.
 ** The purpose of this superclass is to define certain fields that are
 ** common to all module implementations.
 **
-** Virtual tables methods can set an error message by assigning a
+** ^Virtual tables methods can set an error message by assigning a
 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
 ** take care that any prior string is freed by a call to [sqlite3_free()]
-** prior to assigning a new string to zErrMsg.  After the error message
+** prior to assigning a new string to zErrMsg.  ^After the error message
 ** is delivered up to the client application, the string will be automatically
-** freed by sqlite3_free() and the zErrMsg field will be zeroed.  Note
-** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
-** since virtual tables are commonly implemented in loadable extensions which
-** do not have access to sqlite3MPrintf() or sqlite3Free().
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
+** freed by sqlite3_free() and the zErrMsg field will be zeroed.
 */
 struct sqlite3_vtab {
   const sqlite3_module *pModule;  /* The module for this virtual table */
-  int nRef;                       /* Used internally */
+  int nRef;                       /* NO LONGER USED */
   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
   /* Virtual table implementations will typically add additional fields */
 };
 
 /*
-** CAPI3REF: Virtual Table Cursor Object  {H18020} <S20400>
-** KEYWORDS: sqlite3_vtab_cursor
-** EXPERIMENTAL
+** CAPI3REF: Virtual Table Cursor Object
+** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
 **
-** Every module implementation uses a subclass of the following structure
-** to describe cursors that point into the virtual table and are used
+** Every [virtual table module] implementation uses a subclass of the
+** following structure to describe cursors that point into the
+** [virtual table] and are used
 ** to loop through the virtual table.  Cursors are created using the
-** xOpen method of the module.  Each module implementation will define
+** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
+** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
+** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
+** of the module.  Each module implementation will define
 ** the content of a cursor structure to suit its own needs.
 **
 ** This superclass exists in order to define fields of the cursor that
 ** are common to all implementations.
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
 */
 struct sqlite3_vtab_cursor {
   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
@@ -6203,38 +5810,32 @@ struct sqlite3_vtab_cursor {
 };
 
 /*
-** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400>
-** EXPERIMENTAL
+** CAPI3REF: Declare The Schema Of A Virtual Table
 **
-** The xCreate and xConnect methods of a module use the following API
+** ^The [xCreate] and [xConnect] methods of a
+** [virtual table module] call this interface
 ** to declare the format (the names and datatypes of the columns) of
 ** the virtual tables they implement.
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable);
+SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
 
 /*
-** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400>
-** EXPERIMENTAL
+** CAPI3REF: Overload A Function For A Virtual Table
 **
-** Virtual tables can provide alternative implementations of functions
-** using the xFindFunction method.  But global versions of those functions
-** must exist in order to be overloaded.
+** ^(Virtual tables can provide alternative implementations of functions
+** using the [xFindFunction] method of the [virtual table module].  
+** But global versions of those functions
+** must exist in order to be overloaded.)^
 **
-** This API makes sure a global version of a function with a particular
+** ^(This API makes sure a global version of a function with a particular
 ** name and number of parameters exists.  If no such function exists
-** before this API is called, a new function is created.  The implementation
+** before this API is called, a new function is created.)^  ^The implementation
 ** of the new function always causes an exception to be thrown.  So
 ** the new function is not good for anything by itself.  Its only
 ** purpose is to be a placeholder function that can be overloaded
-** by virtual tables.
-**
-** This API should be considered part of the virtual table interface,
-** which is experimental and subject to change.
+** by a [virtual table].
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
+SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
 
 /*
 ** The interface to the virtual-table mechanism defined above (back up
@@ -6244,89 +5845,77 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const cha
 **
 ** When the virtual-table mechanism stabilizes, we will declare the
 ** interface fixed, support it indefinitely, and remove this comment.
-**
-****** EXPERIMENTAL - subject to change without notice **************
 */
 
 /*
-** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230>
+** CAPI3REF: A Handle To An Open BLOB
 ** KEYWORDS: {BLOB handle} {BLOB handles}
 **
 ** An instance of this object represents an open BLOB on which
 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
-** Objects of this type are created by [sqlite3_blob_open()]
+** ^Objects of this type are created by [sqlite3_blob_open()]
 ** and destroyed by [sqlite3_blob_close()].
-** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
+** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
 ** can be used to read or write small subsections of the BLOB.
-** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
+** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
 */
 typedef struct sqlite3_blob sqlite3_blob;
 
 /*
-** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230>
+** CAPI3REF: Open A BLOB For Incremental I/O
 **
-** This interfaces opens a [BLOB handle | handle] to the BLOB located
+** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
 ** in row iRow, column zColumn, table zTable in database zDb;
 ** in other words, the same BLOB that would be selected by:
 **
 ** <pre>
 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
-** </pre> {END}
+** </pre>)^
 **
-** If the flags parameter is non-zero, the the BLOB is opened for read
-** and write access. If it is zero, the BLOB is opened for read access.
+** ^If the flags parameter is non-zero, then the BLOB is opened for read
+** and write access. ^If it is zero, the BLOB is opened for read access.
+** ^It is not possible to open a column that is part of an index or primary 
+** key for writing. ^If [foreign key constraints] are enabled, it is 
+** not possible to open a column that is part of a [child key] for writing.
 **
-** Note that the database name is not the filename that contains
+** ^Note that the database name is not the filename that contains
 ** the database but rather the symbolic name of the database that
-** is assigned when the database is connected using [ATTACH].
-** For the main database file, the database name is "main".
-** For TEMP tables, the database name is "temp".
+** appears after the AS keyword when the database is connected using [ATTACH].
+** ^For the main database file, the database name is "main".
+** ^For TEMP tables, the database name is "temp".
 **
-** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
-** to *ppBlob. Otherwise an [error code] is returned and any value written
-** to *ppBlob should not be used by the caller.
-** This function sets the [database connection] error code and message
-** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()].
+** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
+** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
+** to be a null pointer.)^
+** ^This function sets the [database connection] error code and message
+** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
+** functions. ^Note that the *ppBlob variable is always initialized in a
+** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
+** regardless of the success or failure of this routine.
 **
-** If the row that a BLOB handle points to is modified by an
+** ^(If the row that a BLOB handle points to is modified by an
 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
 ** then the BLOB handle is marked as "expired".
 ** This is true if any column of the row is changed, even a column
-** other than the one the BLOB handle is open on.
-** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
-** a expired BLOB handle fail with an return code of [SQLITE_ABORT].
-** Changes written into a BLOB prior to the BLOB expiring are not
-** rollback by the expiration of the BLOB.  Such changes will eventually
-** commit if the transaction continues to completion.
+** other than the one the BLOB handle is open on.)^
+** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
+** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
+** ^(Changes written into a BLOB prior to the BLOB expiring are not
+** rolled back by the expiration of the BLOB.  Such changes will eventually
+** commit if the transaction continues to completion.)^
 **
-** INVARIANTS:
+** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
+** the opened blob.  ^The size of a blob may not be changed by this
+** interface.  Use the [UPDATE] SQL command to change the size of a
+** blob.
 **
-** {H17813} A successful invocation of the [sqlite3_blob_open(D,B,T,C,R,F,P)]
-**          interface shall open an [sqlite3_blob] object P on the BLOB
-**          in column C of the table T in the database B on
-**          the [database connection] D.
+** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
+** and the built-in [zeroblob] SQL function can be used, if desired,
+** to create an empty, zero-filled blob in which to read or write using
+** this interface.
 **
-** {H17814} A successful invocation of [sqlite3_blob_open(D,...)] shall start
-**          a new transaction on the [database connection] D if that
-**          connection is not already in a transaction.
-**
-** {H17816} The [sqlite3_blob_open(D,B,T,C,R,F,P)] interface shall open
-**          the BLOB for read and write access if and only if the F
-**          parameter is non-zero.
-**
-** {H17819} The [sqlite3_blob_open()] interface shall return [SQLITE_OK] on
-**          success and an appropriate [error code] on failure.
-**
-** {H17821} If an error occurs during evaluation of [sqlite3_blob_open(D,...)]
-**          then subsequent calls to [sqlite3_errcode(D)],
-**          [sqlite3_extended_errcode()], 
-**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] shall return
-**          information appropriate for that error.
-**
-** {H17824} If any column in the row that a [sqlite3_blob] has open is
-**          changed by a separate [UPDATE] or [DELETE] statement or by
-**          an [ON CONFLICT] side effect, then the [sqlite3_blob] shall
-**          be marked as invalid.
+** To avoid a resource leak, every open [BLOB handle] should eventually
+** be released by a call to [sqlite3_blob_close()].
 */
 SQLITE_API int sqlite3_blob_open(
   sqlite3*,
@@ -6339,178 +5928,136 @@ SQLITE_API int sqlite3_blob_open(
 );
 
 /*
-** CAPI3REF: Close A BLOB Handle {H17830} <S30230>
+** CAPI3REF: Move a BLOB Handle to a New Row
 **
-** Closes an open [BLOB handle].
+** ^This function is used to move an existing blob handle so that it points
+** to a different row of the same database table. ^The new row is identified
+** by the rowid value passed as the second argument. Only the row can be
+** changed. ^The database, table and column on which the blob handle is open
+** remain the same. Moving an existing blob handle to a new row can be
+** faster than closing the existing handle and opening a new one.
 **
-** Closing a BLOB shall cause the current transaction to commit
+** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
+** it must exist and there must be either a blob or text value stored in
+** the nominated column.)^ ^If the new row is not present in the table, or if
+** it does not contain a blob or text value, or if another error occurs, an
+** SQLite error code is returned and the blob handle is considered aborted.
+** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
+** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
+** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
+** always returns zero.
+**
+** ^This function sets the database handle error code and message.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
+
+/*
+** CAPI3REF: Close A BLOB Handle
+**
+** ^Closes an open [BLOB handle].
+**
+** ^Closing a BLOB shall cause the current transaction to commit
 ** if there are no other BLOBs, no pending prepared statements, and the
 ** database connection is in [autocommit mode].
-** If any writes were made to the BLOB, they might be held in cache
-** until the close operation if they will fit. {END}
+** ^If any writes were made to the BLOB, they might be held in cache
+** until the close operation if they will fit.
 **
-** Closing the BLOB often forces the changes
+** ^(Closing the BLOB often forces the changes
 ** out to disk and so if any I/O errors occur, they will likely occur
-** at the time when the BLOB is closed.  {H17833} Any errors that occur during
-** closing are reported as a non-zero return value.
+** at the time when the BLOB is closed.  Any errors that occur during
+** closing are reported as a non-zero return value.)^
 **
-** The BLOB is closed unconditionally.  Even if this routine returns
-** an error code, the BLOB is still closed.
+** ^(The BLOB is closed unconditionally.  Even if this routine returns
+** an error code, the BLOB is still closed.)^
 **
-** INVARIANTS:
-**
-** {H17833} The [sqlite3_blob_close(P)] interface closes an [sqlite3_blob]
-**          object P previously opened using [sqlite3_blob_open()].
-**
-** {H17836} Closing an [sqlite3_blob] object using
-**          [sqlite3_blob_close()] shall cause the current transaction to
-**          commit if there are no other open [sqlite3_blob] objects
-**          or [prepared statements] on the same [database connection] and
-**          the database connection is in [autocommit mode].
-**
-** {H17839} The [sqlite3_blob_close(P)] interfaces shall close the
-**          [sqlite3_blob] object P unconditionally, even if
-**          [sqlite3_blob_close(P)] returns something other than [SQLITE_OK].
+** ^Calling this routine with a null pointer (such as would be returned
+** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
 */
 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
 
 /*
-** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230>
+** CAPI3REF: Return The Size Of An Open BLOB
 **
-** Returns the size in bytes of the BLOB accessible via the open
-** []BLOB handle] in its only argument.
+** ^Returns the size in bytes of the BLOB accessible via the 
+** successfully opened [BLOB handle] in its only argument.  ^The
+** incremental blob I/O routines can only read or overwriting existing
+** blob content; they cannot change the size of a blob.
 **
-** INVARIANTS:
-**
-** {H17843} The [sqlite3_blob_bytes(P)] interface returns the size
-**          in bytes of the BLOB that the [sqlite3_blob] object P
-**          refers to.
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
 */
 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
 
 /*
-** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230>
+** CAPI3REF: Read Data From A BLOB Incrementally
 **
-** This function is used to read data from an open [BLOB handle] into a
+** ^(This function is used to read data from an open [BLOB handle] into a
 ** caller-supplied buffer. N bytes of data are copied into buffer Z
-** from the open BLOB, starting at offset iOffset.
+** from the open BLOB, starting at offset iOffset.)^
 **
-** If offset iOffset is less than N bytes from the end of the BLOB,
-** [SQLITE_ERROR] is returned and no data is read.  If N or iOffset is
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
+** ^The size of the blob (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
 **
-** An attempt to read from an expired [BLOB handle] fails with an
+** ^An attempt to read from an expired [BLOB handle] fails with an
 ** error code of [SQLITE_ABORT].
 **
-** On success, SQLITE_OK is returned.
-** Otherwise, an [error code] or an [extended error code] is returned.
+** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
+** Otherwise, an [error code] or an [extended error code] is returned.)^
 **
-** INVARIANTS:
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
 **
-** {H17853} A successful invocation of [sqlite3_blob_read(P,Z,N,X)] 
-**          shall reads N bytes of data out of the BLOB referenced by
-**          [BLOB handle] P beginning at offset X and store those bytes
-**          into buffer Z.
-**
-** {H17856} In [sqlite3_blob_read(P,Z,N,X)] if the size of the BLOB
-**          is less than N+X bytes, then the function shall leave the
-**          Z buffer unchanged and return [SQLITE_ERROR].
-**
-** {H17859} In [sqlite3_blob_read(P,Z,N,X)] if X or N is less than zero
-**          then the function shall leave the Z buffer unchanged
-**          and return [SQLITE_ERROR].
-**
-** {H17862} The [sqlite3_blob_read(P,Z,N,X)] interface shall return [SQLITE_OK]
-**          if N bytes are successfully read into buffer Z.
-**
-** {H17863} If the [BLOB handle] P is expired and X and N are within bounds
-**          then [sqlite3_blob_read(P,Z,N,X)] shall leave the Z buffer
-**          unchanged and return [SQLITE_ABORT].
-**
-** {H17865} If the requested read could not be completed,
-**          the [sqlite3_blob_read(P,Z,N,X)] interface shall return an
-**          appropriate [error code] or [extended error code].
-**
-** {H17868} If an error occurs during evaluation of [sqlite3_blob_read(P,...)]
-**          then subsequent calls to [sqlite3_errcode(D)],
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] shall return
-**          information appropriate for that error, where D is the
-**          [database connection] that was used to open the [BLOB handle] P.
+** See also: [sqlite3_blob_write()].
 */
 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
 
 /*
-** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230>
+** CAPI3REF: Write Data Into A BLOB Incrementally
 **
-** This function is used to write data into an open [BLOB handle] from a
-** caller-supplied buffer. N bytes of data are copied from the buffer Z
+** ^This function is used to write data into an open [BLOB handle] from a
+** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
 ** into the open BLOB, starting at offset iOffset.
 **
-** If the [BLOB handle] passed as the first argument was not opened for
+** ^If the [BLOB handle] passed as the first argument was not opened for
 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
 ** this function returns [SQLITE_READONLY].
 **
-** This function may only modify the contents of the BLOB; it is
+** ^This function may only modify the contents of the BLOB; it is
 ** not possible to increase the size of a BLOB using this API.
-** If offset iOffset is less than N bytes from the end of the BLOB,
-** [SQLITE_ERROR] is returned and no data is written.  If N is
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is written.  ^If N is
 ** less than zero [SQLITE_ERROR] is returned and no data is written.
+** The size of the BLOB (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
 **
-** An attempt to write to an expired [BLOB handle] fails with an
-** error code of [SQLITE_ABORT].  Writes to the BLOB that occurred
+** ^An attempt to write to an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
 ** before the [BLOB handle] expired are not rolled back by the
 ** expiration of the handle, though of course those changes might
 ** have been overwritten by the statement that expired the BLOB handle
 ** or by other independent statements.
 **
-** On success, SQLITE_OK is returned.
-** Otherwise, an  [error code] or an [extended error code] is returned.
+** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
+** Otherwise, an  [error code] or an [extended error code] is returned.)^
 **
-** INVARIANTS:
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
 **
-** {H17873} A successful invocation of [sqlite3_blob_write(P,Z,N,X)]
-**          shall write N bytes of data from buffer Z into the BLOB 
-**          referenced by [BLOB handle] P beginning at offset X into
-**          the BLOB.
-**
-** {H17874} In the absence of other overridding changes, the changes
-**          written to a BLOB by [sqlite3_blob_write()] shall
-**          remain in effect after the associated [BLOB handle] expires.
-**
-** {H17875} If the [BLOB handle] P was opened for reading only then
-**          an invocation of [sqlite3_blob_write(P,Z,N,X)] shall leave
-**          the referenced BLOB unchanged and return [SQLITE_READONLY].
-**
-** {H17876} If the size of the BLOB referenced by [BLOB handle] P is
-**          less than N+X bytes then [sqlite3_blob_write(P,Z,N,X)] shall
-**          leave the BLOB unchanged and return [SQLITE_ERROR].
-**
-** {H17877} If the [BLOB handle] P is expired and X and N are within bounds
-**          then [sqlite3_blob_read(P,Z,N,X)] shall leave the BLOB
-**          unchanged and return [SQLITE_ABORT].
-**
-** {H17879} If X or N are less than zero then [sqlite3_blob_write(P,Z,N,X)]
-**          shall leave the BLOB referenced by [BLOB handle] P unchanged
-**          and return [SQLITE_ERROR].
-**
-** {H17882} The [sqlite3_blob_write(P,Z,N,X)] interface shall return
-**          [SQLITE_OK] if N bytes where successfully written into the BLOB.
-**
-** {H17885} If the requested write could not be completed,
-**          the [sqlite3_blob_write(P,Z,N,X)] interface shall return an
-**          appropriate [error code] or [extended error code].
-**
-** {H17888} If an error occurs during evaluation of [sqlite3_blob_write(D,...)]
-**          then subsequent calls to [sqlite3_errcode(D)],
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] shall return
-**          information appropriate for that error.
+** See also: [sqlite3_blob_read()].
 */
 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
 
 /*
-** CAPI3REF: Virtual File System Objects {H11200} <S20100>
+** CAPI3REF: Virtual File System Objects
 **
 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
 ** that SQLite uses to interact
@@ -6519,57 +6066,31 @@ SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOff
 ** New VFSes can be registered and existing VFSes can be unregistered.
 ** The following interfaces are provided.
 **
-** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
-** Names are case sensitive.
-** Names are zero-terminated UTF-8 strings.
-** If there is no match, a NULL pointer is returned.
-** If zVfsName is NULL then the default VFS is returned.
+** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
+** ^Names are case sensitive.
+** ^Names are zero-terminated UTF-8 strings.
+** ^If there is no match, a NULL pointer is returned.
+** ^If zVfsName is NULL then the default VFS is returned.
 **
-** New VFSes are registered with sqlite3_vfs_register().
-** Each new VFS becomes the default VFS if the makeDflt flag is set.
-** The same VFS can be registered multiple times without injury.
-** To make an existing VFS into the default VFS, register it again
+** ^New VFSes are registered with sqlite3_vfs_register().
+** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
+** ^The same VFS can be registered multiple times without injury.
+** ^To make an existing VFS into the default VFS, register it again
 ** with the makeDflt flag set.  If two different VFSes with the
 ** same name are registered, the behavior is undefined.  If a
 ** VFS is registered with a name that is NULL or an empty string,
 ** then the behavior is undefined.
 **
-** Unregister a VFS with the sqlite3_vfs_unregister() interface.
-** If the default VFS is unregistered, another VFS is chosen as
-** the default.  The choice for the new VFS is arbitrary.
-**
-** INVARIANTS:
-**
-** {H11203} The [sqlite3_vfs_find(N)] interface returns a pointer to the
-**          registered [sqlite3_vfs] object whose name exactly matches
-**          the zero-terminated UTF-8 string N, or it returns NULL if
-**          there is no match.
-**
-** {H11206} If the N parameter to [sqlite3_vfs_find(N)] is NULL then
-**          the function returns a pointer to the default [sqlite3_vfs]
-**          object if there is one, or NULL if there is no default
-**          [sqlite3_vfs] object.
-**
-** {H11209} The [sqlite3_vfs_register(P,F)] interface registers the
-**          well-formed [sqlite3_vfs] object P using the name given
-**          by the zName field of the object.
-**
-** {H11212} Using the [sqlite3_vfs_register(P,F)] interface to register
-**          the same [sqlite3_vfs] object multiple times is a harmless no-op.
-**
-** {H11215} The [sqlite3_vfs_register(P,F)] interface makes the [sqlite3_vfs]
-**          object P the default [sqlite3_vfs] object if F is non-zero.
-**
-** {H11218} The [sqlite3_vfs_unregister(P)] interface unregisters the
-**          [sqlite3_vfs] object P so that it is no longer returned by
-**          subsequent calls to [sqlite3_vfs_find()].
+** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
+** ^(If the default VFS is unregistered, another VFS is chosen as
+** the default.  The choice for the new VFS is arbitrary.)^
 */
 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
 
 /*
-** CAPI3REF: Mutexes {H17000} <S20000>
+** CAPI3REF: Mutexes
 **
 ** The SQLite core uses these routines for thread
 ** synchronization. Though they are intended for internal
@@ -6578,34 +6099,33 @@ SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
 **
 ** The SQLite source code contains multiple implementations
 ** of these mutex routines.  An appropriate implementation
-** is selected automatically at compile-time.  The following
+** is selected automatically at compile-time.  ^(The following
 ** implementations are available in the SQLite core:
 **
 ** <ul>
-** <li>   SQLITE_MUTEX_OS2
-** <li>   SQLITE_MUTEX_PTHREAD
+** <li>   SQLITE_MUTEX_PTHREADS
 ** <li>   SQLITE_MUTEX_W32
 ** <li>   SQLITE_MUTEX_NOOP
-** </ul>
+** </ul>)^
 **
-** The SQLITE_MUTEX_NOOP implementation is a set of routines
+** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
 ** that does no real locking and is appropriate for use in
-** a single-threaded application.  The SQLITE_MUTEX_OS2,
-** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
-** are appropriate for use on OS/2, Unix, and Windows.
+** a single-threaded application.  ^The SQLITE_MUTEX_PTHREADS and
+** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
+** and Windows.
 **
-** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
+** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
 ** implementation is included with the library. In this case the
 ** application must supply a custom mutex implementation using the
 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
 ** before calling sqlite3_initialize() or any other public sqlite3_
-** function that calls sqlite3_initialize().
+** function that calls sqlite3_initialize().)^
 **
-** {H17011} The sqlite3_mutex_alloc() routine allocates a new
-** mutex and returns a pointer to it. {H17012} If it returns NULL
-** that means that a mutex could not be allocated. {H17013} SQLite
-** will unwind its stack and return an error. {H17014} The argument
+** ^The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it. ^If it returns NULL
+** that means that a mutex could not be allocated.  ^SQLite
+** will unwind its stack and return an error.  ^(The argument
 ** to sqlite3_mutex_alloc() is one of these integer constants:
 **
 ** <ul>
@@ -6617,64 +6137,66 @@ SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
 ** <li>  SQLITE_MUTEX_STATIC_PRNG
 ** <li>  SQLITE_MUTEX_STATIC_LRU
 ** <li>  SQLITE_MUTEX_STATIC_LRU2
-** </ul>
+** </ul>)^
 **
-** {H17015} The first two constants cause sqlite3_mutex_alloc() to create
-** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
-** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
+** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
+** cause sqlite3_mutex_alloc() to create
+** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
 ** The mutex implementation does not need to make a distinction
 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
-** not want to.  {H17016} But SQLite will only request a recursive mutex in
-** cases where it really needs one.  {END} If a faster non-recursive mutex
+** not want to.  ^SQLite will only request a recursive mutex in
+** cases where it really needs one.  ^If a faster non-recursive mutex
 ** implementation is available on the host platform, the mutex subsystem
 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
 **
-** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return
-** a pointer to a static preexisting mutex. {END}  Four static mutexes are
+** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
+** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
+** a pointer to a static preexisting mutex.  ^Six static mutexes are
 ** used by the current version of SQLite.  Future versions of SQLite
 ** may add additional static mutexes.  Static mutexes are for internal
 ** use by SQLite only.  Applications that use SQLite mutexes should
 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
 ** SQLITE_MUTEX_RECURSIVE.
 **
-** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
-** returns a different mutex on every call.  {H17034} But for the static
+** returns a different mutex on every call.  ^But for the static
 ** mutex types, the same mutex is returned on every call that has
 ** the same type number.
 **
-** {H17019} The sqlite3_mutex_free() routine deallocates a previously
-** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every
-** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in
-** use when they are deallocated. {A17022} Attempting to deallocate a static
-** mutex results in undefined behavior. {H17023} SQLite never deallocates
-** a static mutex. {END}
+** ^The sqlite3_mutex_free() routine deallocates a previously
+** allocated dynamic mutex.  ^SQLite is careful to deallocate every
+** dynamic mutex that it allocates.  The dynamic mutexes must not be in
+** use when they are deallocated.  Attempting to deallocate a static
+** mutex results in undefined behavior.  ^SQLite never deallocates
+** a static mutex.
 **
-** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
-** to enter a mutex. {H17024} If another thread is already within the mutex,
+** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  ^If another thread is already within the mutex,
 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
-** SQLITE_BUSY. {H17025}  The sqlite3_mutex_try() interface returns [SQLITE_OK]
-** upon successful entry.  {H17026} Mutexes created using
+** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
+** upon successful entry.  ^(Mutexes created using
 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
-** {H17027} In such cases the,
+** In such cases the,
 ** mutex must be exited an equal number of times before another thread
-** can enter.  {A17028} If the same thread tries to enter any other
+** can enter.)^  ^(If the same thread tries to enter any other
 ** kind of mutex more than once, the behavior is undefined.
-** {H17029} SQLite will never exhibit
-** such behavior in its own use of mutexes.
+** SQLite will never exhibit
+** such behavior in its own use of mutexes.)^
 **
-** Some systems (for example, Windows 95) do not support the operation
+** ^(Some systems (for example, Windows 95) do not support the operation
 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
-** will always return SQLITE_BUSY.  {H17030} The SQLite core only ever uses
-** sqlite3_mutex_try() as an optimization so this is acceptable behavior.
+** will always return SQLITE_BUSY.  The SQLite core only ever uses
+** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
 **
-** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was
-** previously entered by the same thread.  {A17032} The behavior
+** ^The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.   ^(The behavior
 ** is undefined if the mutex is not currently entered by the
-** calling thread or is not currently allocated.  {H17033} SQLite will
-** never do either. {END}
+** calling thread or is not currently allocated.  SQLite will
+** never do either.)^
 **
-** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
+** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
 ** behave as no-ops.
 **
@@ -6687,8 +6209,7 @@ SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
 
 /*
-** CAPI3REF: Mutex Methods Object {H17120} <S20130>
-** EXPERIMENTAL
+** CAPI3REF: Mutex Methods Object
 **
 ** An instance of this structure defines the low-level routines
 ** used to allocate and use mutexes.
@@ -6703,19 +6224,19 @@ SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
 ** output variable when querying the system for the current mutex
 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
 **
-** The xMutexInit method defined by this structure is invoked as
+** ^The xMutexInit method defined by this structure is invoked as
 ** part of system initialization by the sqlite3_initialize() function.
-** {H17001} The xMutexInit routine shall be called by SQLite once for each
+** ^The xMutexInit routine is called by SQLite exactly once for each
 ** effective call to [sqlite3_initialize()].
 **
-** The xMutexEnd method defined by this structure is invoked as
+** ^The xMutexEnd method defined by this structure is invoked as
 ** part of system shutdown by the sqlite3_shutdown() function. The
 ** implementation of this method is expected to release all outstanding
 ** resources obtained by the mutex methods implementation, especially
-** those obtained by the xMutexInit method. {H17003} The xMutexEnd()
-** interface shall be invoked once for each call to [sqlite3_shutdown()].
+** those obtained by the xMutexInit method.  ^The xMutexEnd()
+** interface is invoked exactly once for each call to [sqlite3_shutdown()].
 **
-** The remaining seven methods defined by this structure (xMutexAlloc,
+** ^(The remaining seven methods defined by this structure (xMutexAlloc,
 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
 ** xMutexNotheld) implement the following interfaces (respectively):
 **
@@ -6727,7 +6248,7 @@ SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
 **   <li>  [sqlite3_mutex_leave()] </li>
 **   <li>  [sqlite3_mutex_held()] </li>
 **   <li>  [sqlite3_mutex_notheld()] </li>
-** </ul>
+** </ul>)^
 **
 ** The only difference is that the public sqlite3_XXX functions enumerated
 ** above silently ignore any invocations that pass a NULL pointer instead
@@ -6736,6 +6257,21 @@ SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
 ** of passing a NULL pointer instead of a valid mutex handle are undefined
 ** (i.e. it is acceptable to provide an implementation that segfaults if
 ** it is passed a NULL pointer).
+**
+** The xMutexInit() method must be threadsafe.  ^It must be harmless to
+** invoke xMutexInit() multiple times within the same process and without
+** intervening calls to xMutexEnd().  Second and subsequent calls to
+** xMutexInit() must be no-ops.
+**
+** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
+** and its associates).  ^Similarly, xMutexAlloc() must not use SQLite memory
+** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
+** memory allocation for a fast or recursive mutex.
+**
+** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
+** called, but only if the prior call to xMutexInit returned SQLITE_OK.
+** If xMutexInit fails in any way, it is expected to clean up after itself
+** prior to returning.
 */
 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
 struct sqlite3_mutex_methods {
@@ -6751,39 +6287,41 @@ struct sqlite3_mutex_methods {
 };
 
 /*
-** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800>
+** CAPI3REF: Mutex Verification Routines
 **
 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
-** are intended for use inside assert() statements. {H17081} The SQLite core
+** are intended for use inside assert() statements.  ^The SQLite core
 ** never uses these routines except inside an assert() and applications
-** are advised to follow the lead of the core.  {H17082} The core only
+** are advised to follow the lead of the core.  ^The SQLite core only
 ** provides implementations for these routines when it is compiled
-** with the SQLITE_DEBUG flag.  {A17087} External mutex implementations
+** with the SQLITE_DEBUG flag.  ^External mutex implementations
 ** are only required to provide these routines if SQLITE_DEBUG is
 ** defined and if NDEBUG is not defined.
 **
-** {H17083} These routines should return true if the mutex in their argument
+** ^These routines should return true if the mutex in their argument
 ** is held or not held, respectively, by the calling thread.
 **
-** {X17084} The implementation is not required to provided versions of these
+** ^The implementation is not required to provide versions of these
 ** routines that actually work. If the implementation does not provide working
 ** versions of these routines, it should at least provide stubs that always
 ** return true so that one does not get spurious assertion failures.
 **
-** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then
-** the routine should return 1.  {END} This seems counter-intuitive since
-** clearly the mutex cannot be held if it does not exist.  But the
+** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
+** the routine should return 1.   This seems counter-intuitive since
+** clearly the mutex cannot be held if it does not exist.  But
 ** the reason the mutex does not exist is because the build is not
 ** using mutexes.  And we do not want the assert() containing the
 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
-** the appropriate thing to do.  {H17086} The sqlite3_mutex_notheld()
+** the appropriate thing to do.  ^The sqlite3_mutex_notheld()
 ** interface should also return 1 when given a NULL pointer.
 */
+#ifndef NDEBUG
 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
+#endif
 
 /*
-** CAPI3REF: Mutex Types {H17001} <H17000>
+** CAPI3REF: Mutex Types
 **
 ** The [sqlite3_mutex_alloc()] interface takes a single argument
 ** which is one of these integer constants.
@@ -6796,54 +6334,64 @@ SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
 #define SQLITE_MUTEX_RECURSIVE        1
 #define SQLITE_MUTEX_STATIC_MASTER    2
 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
-#define SQLITE_MUTEX_STATIC_MEM2      4  /* sqlite3_release_memory() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
-#define SQLITE_MUTEX_STATIC_LRU2      7  /* lru page list */
+#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
 
 /*
-** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000>
+** CAPI3REF: Retrieve the mutex for a database connection
 **
-** This interface returns a pointer the [sqlite3_mutex] object that 
+** ^This interface returns a pointer the [sqlite3_mutex] object that 
 ** serializes access to the [database connection] given in the argument
 ** when the [threading mode] is Serialized.
-** If the [threading mode] is Single-thread or Multi-thread then this
+** ^If the [threading mode] is Single-thread or Multi-thread then this
 ** routine returns a NULL pointer.
 */
 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
 
 /*
-** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800>
+** CAPI3REF: Low-Level Control Of Database Files
 **
-** {H11301} The [sqlite3_file_control()] interface makes a direct call to the
+** ^The [sqlite3_file_control()] interface makes a direct call to the
 ** xFileControl method for the [sqlite3_io_methods] object associated
-** with a particular database identified by the second argument. {H11302} The
-** name of the database is the name assigned to the database by the
-** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
-** database. {H11303} To control the main database file, use the name "main"
-** or a NULL pointer. {H11304} The third and fourth parameters to this routine
+** with a particular database identified by the second argument. ^The
+** name of the database is "main" for the main database or "temp" for the
+** TEMP database, or the name that appears after the AS keyword for
+** databases that are added using the [ATTACH] SQL command.
+** ^A NULL pointer can be used in place of "main" to refer to the
+** main database file.
+** ^The third and fourth parameters to this routine
 ** are passed directly through to the second and third parameters of
-** the xFileControl method.  {H11305} The return value of the xFileControl
+** the xFileControl method.  ^The return value of the xFileControl
 ** method becomes the return value of this routine.
 **
-** {H11306} If the second parameter (zDbName) does not match the name of any
-** open database file, then SQLITE_ERROR is returned. {H11307} This error
+** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
+** a pointer to the underlying [sqlite3_file] object to be written into
+** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
+** case is a short-circuit path which does not actually invoke the
+** underlying sqlite3_io_methods.xFileControl method.
+**
+** ^If the second parameter (zDbName) does not match the name of any
+** open database file, then SQLITE_ERROR is returned.  ^This error
 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
-** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might
-** also return SQLITE_ERROR.  {A11309} There is no way to distinguish between
+** or [sqlite3_errmsg()].  The underlying xFileControl method might
+** also return SQLITE_ERROR.  There is no way to distinguish between
 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
-** xFileControl method. {END}
+** xFileControl method.
 **
 ** See also: [SQLITE_FCNTL_LOCKSTATE]
 */
 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
 
 /*
-** CAPI3REF: Testing Interface {H11400} <S30800>
+** CAPI3REF: Testing Interface
 **
-** The sqlite3_test_control() interface is used to read out internal
+** ^The sqlite3_test_control() interface is used to read out internal
 ** state of SQLite and to inject faults into SQLite for testing
-** purposes.  The first parameter is an operation code that determines
+** purposes.  ^The first parameter is an operation code that determines
 ** the number, meaning, and operation of all subsequent parameters.
 **
 ** This interface is not for use by applications.  It exists solely
@@ -6858,7 +6406,7 @@ SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*
 SQLITE_API int sqlite3_test_control(int op, ...);
 
 /*
-** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400>
+** CAPI3REF: Testing Interface Operation Codes
 **
 ** These constants are the valid operation code parameters used
 ** as the first argument to [sqlite3_test_control()].
@@ -6868,35 +6416,45 @@ SQLITE_API int sqlite3_test_control(int op, ...);
 ** Applications should not use any of these parameters or the
 ** [sqlite3_test_control()] interface.
 */
+#define SQLITE_TESTCTRL_FIRST                    5
 #define SQLITE_TESTCTRL_PRNG_SAVE                5
 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
 #define SQLITE_TESTCTRL_PRNG_RESET               7
 #define SQLITE_TESTCTRL_BITVEC_TEST              8
 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
+#define SQLITE_TESTCTRL_PENDING_BYTE            11
+#define SQLITE_TESTCTRL_ASSERT                  12
+#define SQLITE_TESTCTRL_ALWAYS                  13
+#define SQLITE_TESTCTRL_RESERVE                 14
+#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
+#define SQLITE_TESTCTRL_ISKEYWORD               16
+#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
+#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
+#define SQLITE_TESTCTRL_EXPLAIN_STMT            19
+#define SQLITE_TESTCTRL_LAST                    19
 
 /*
-** CAPI3REF: SQLite Runtime Status {H17200} <S60200>
-** EXPERIMENTAL
+** CAPI3REF: SQLite Runtime Status
 **
-** This interface is used to retrieve runtime status information
-** about the preformance of SQLite, and optionally to reset various
-** highwater marks.  The first argument is an integer code for
-** the specific parameter to measure.  Recognized integer codes
-** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].
-** The current value of the parameter is returned into *pCurrent.
-** The highest recorded value is returned in *pHighwater.  If the
+** ^This interface is used to retrieve runtime status information
+** about the performance of SQLite, and optionally to reset various
+** highwater marks.  ^The first argument is an integer code for
+** the specific parameter to measure.  ^(Recognized integer codes
+** are of the form [status parameters | SQLITE_STATUS_...].)^
+** ^The current value of the parameter is returned into *pCurrent.
+** ^The highest recorded value is returned in *pHighwater.  ^If the
 ** resetFlag is true, then the highest record value is reset after
-** *pHighwater is written. Some parameters do not record the highest
+** *pHighwater is written.  ^(Some parameters do not record the highest
 ** value.  For those parameters
-** nothing is written into *pHighwater and the resetFlag is ignored.
-** Other parameters record only the highwater mark and not the current
-** value.  For these latter parameters nothing is written into *pCurrent.
+** nothing is written into *pHighwater and the resetFlag is ignored.)^
+** ^(Other parameters record only the highwater mark and not the current
+** value.  For these latter parameters nothing is written into *pCurrent.)^
 **
-** This routine returns SQLITE_OK on success and a non-zero
-** [error code] on failure.
+** ^The sqlite3_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
 **
-** This routine is threadsafe but is not atomic.  This routine can
+** This routine is threadsafe but is not atomic.  This routine can be
 ** called while other threads are running the same or different SQLite
 ** interfaces.  However the values returned in *pCurrent and
 ** *pHighwater reflect the status of SQLite at different points in time
@@ -6905,18 +6463,18 @@ SQLITE_API int sqlite3_test_control(int op, ...);
 **
 ** See also: [sqlite3_db_status()]
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
 
 
 /*
-** CAPI3REF: Status Parameters {H17250} <H17200>
-** EXPERIMENTAL
+** CAPI3REF: Status Parameters
+** KEYWORDS: {status parameters}
 **
 ** These integer constants designate various run-time status parameters
 ** that can be returned by [sqlite3_status()].
 **
 ** <dl>
-** <dt>SQLITE_STATUS_MEMORY_USED</dt>
+** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
 ** <dd>This parameter is the current amount of memory checked out
 ** using [sqlite3_malloc()], either directly or indirectly.  The
 ** figure includes calls made to [sqlite3_malloc()] by the application
@@ -6924,63 +6482,68 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pH
 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
 ** this parameter.  The amount returned is the sum of the allocation
-** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>
+** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
 **
-** <dt>SQLITE_STATUS_MALLOC_SIZE</dt>
+** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
 ** internal equivalents).  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
-** The value written into the *pCurrent parameter is undefined.</dd>
+** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
-** <dt>SQLITE_STATUS_PAGECACHE_USED</dt>
+** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
+** <dd>This parameter records the number of separate memory allocations
+** currently checked out.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
 ** <dd>This parameter returns the number of pages used out of the
 ** [pagecache memory allocator] that was configured using 
 ** [SQLITE_CONFIG_PAGECACHE].  The
-** value returned is in pages, not in bytes.</dd>
+** value returned is in pages, not in bytes.</dd>)^
 **
-** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
+** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 
+** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
 ** <dd>This parameter returns the number of bytes of page cache
-** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE]
+** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
 ** returned value includes allocations that overflowed because they
 ** where too large (they were larger than the "sz" parameter to
 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
-** no space was left in the page cache.</dd>
+** no space was left in the page cache.</dd>)^
 **
-** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
+** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [pagecache memory allocator].  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
-** The value written into the *pCurrent parameter is undefined.</dd>
+** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
-** <dt>SQLITE_STATUS_SCRATCH_USED</dt>
+** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
 ** <dd>This parameter returns the number of allocations used out of the
 ** [scratch memory allocator] configured using
 ** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
 ** in bytes.  Since a single thread may only have one scratch allocation
 ** outstanding at time, this parameter also reports the number of threads
-** using scratch memory at the same time.</dd>
+** using scratch memory at the same time.</dd>)^
 **
-** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
+** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
 ** <dd>This parameter returns the number of bytes of scratch memory
-** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH]
+** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
 ** buffer and where forced to overflow to [sqlite3_malloc()].  The values
 ** returned include overflows because the requested allocation was too
 ** larger (that is, because the requested allocation was larger than the
 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
 ** slots were available.
-** </dd>
+** </dd>)^
 **
-** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
+** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [scratch memory allocator].  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
-** The value written into the *pCurrent parameter is undefined.</dd>
+** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
-** <dt>SQLITE_STATUS_PARSER_STACK</dt>
+** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
 ** <dd>This parameter records the deepest parser stack.  It is only
-** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>
+** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
 ** </dl>
 **
 ** New status parameters may be added from time to time.
@@ -6994,96 +6557,188 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pH
 #define SQLITE_STATUS_PARSER_STACK         6
 #define SQLITE_STATUS_PAGECACHE_SIZE       7
 #define SQLITE_STATUS_SCRATCH_SIZE         8
+#define SQLITE_STATUS_MALLOC_COUNT         9
 
 /*
-** CAPI3REF: Database Connection Status {H17500} <S60200>
-** EXPERIMENTAL
+** CAPI3REF: Database Connection Status
 **
-** This interface is used to retrieve runtime status information 
-** about a single [database connection].  The first argument is the
-** database connection object to be interrogated.  The second argument
-** is the parameter to interrogate.  Currently, the only allowed value
-** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED].
-** Additional options will likely appear in future releases of SQLite.
+** ^This interface is used to retrieve runtime status information 
+** about a single [database connection].  ^The first argument is the
+** database connection object to be interrogated.  ^The second argument
+** is an integer constant, taken from the set of
+** [SQLITE_DBSTATUS options], that
+** determines the parameter to interrogate.  The set of 
+** [SQLITE_DBSTATUS options] is likely
+** to grow in future releases of SQLite.
 **
-** The current value of the requested parameter is written into *pCur
-** and the highest instantaneous value is written into *pHiwtr.  If
+** ^The current value of the requested parameter is written into *pCur
+** and the highest instantaneous value is written into *pHiwtr.  ^If
 ** the resetFlg is true, then the highest instantaneous value is
 ** reset back down to the current value.
 **
+** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
+**
 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
+SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
 
 /*
-** CAPI3REF: Status Parameters for database connections {H17520} <H17500>
-** EXPERIMENTAL
+** CAPI3REF: Status Parameters for database connections
+** KEYWORDS: {SQLITE_DBSTATUS options}
 **
-** Status verbs for [sqlite3_db_status()].
+** These constants are the available integer "verbs" that can be passed as
+** the second argument to the [sqlite3_db_status()] interface.
+**
+** New verbs may be added in future releases of SQLite. Existing verbs
+** might be discontinued. Applications should check the return code from
+** [sqlite3_db_status()] to make sure that the call worked.
+** The [sqlite3_db_status()] interface will return a non-zero error code
+** if a discontinued or unsupported verb is invoked.
 **
 ** <dl>
-** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
+** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
 ** <dd>This parameter returns the number of lookaside memory slots currently
-** checked out.</dd>
+** checked out.</dd>)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
+** <dd>This parameter returns the number malloc attempts that were 
+** satisfied using lookaside memory. Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to the amount of
+** memory requested being larger than the lookaside slot size.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to all lookaside
+** memory already being in use.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
+** <dd>This parameter returns the approximate number of of bytes of heap
+** memory used by all pager caches associated with the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
+** <dd>This parameter returns the approximate number of of bytes of heap
+** memory used to store the schema for all databases associated
+** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 
+** ^The full amount of memory used by the schemas is reported, even if the
+** schema memory is shared with other database connections due to
+** [shared cache mode] being enabled.
+** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
+** <dd>This parameter returns the approximate number of of bytes of heap
+** and lookaside memory used by all prepared statements associated with
+** the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
+** <dd>This parameter returns the number of pager cache hits that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
+** <dd>This parameter returns the number of pager cache misses that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk. Specifically, the number of pages written to the
+** wal file in wal mode databases, or the number of pages written to the
+** database file in rollback mode databases. Any pages written as part of
+** transaction rollback or database recovery operations are not included.
+** If an IO or other error occurs while writing a page to disk, the effect
+** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
+** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
+** </dd>
 ** </dl>
 */
-#define SQLITE_DBSTATUS_LOOKASIDE_USED     0
+#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
+#define SQLITE_DBSTATUS_CACHE_USED           1
+#define SQLITE_DBSTATUS_SCHEMA_USED          2
+#define SQLITE_DBSTATUS_STMT_USED            3
+#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
+#define SQLITE_DBSTATUS_CACHE_HIT            7
+#define SQLITE_DBSTATUS_CACHE_MISS           8
+#define SQLITE_DBSTATUS_CACHE_WRITE          9
+#define SQLITE_DBSTATUS_MAX                  9   /* Largest defined DBSTATUS */
 
 
 /*
-** CAPI3REF: Prepared Statement Status {H17550} <S60200>
-** EXPERIMENTAL
+** CAPI3REF: Prepared Statement Status
 **
-** Each prepared statement maintains various
-** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
-** of times it has performed specific operations.  These counters can
+** ^(Each prepared statement maintains various
+** [SQLITE_STMTSTATUS counters] that measure the number
+** of times it has performed specific operations.)^  These counters can
 ** be used to monitor the performance characteristics of the prepared
 ** statements.  For example, if the number of table steps greatly exceeds
 ** the number of table searches or result rows, that would tend to indicate
 ** that the prepared statement is using a full table scan rather than
 ** an index.  
 **
-** This interface is used to retrieve and reset counter values from
+** ^(This interface is used to retrieve and reset counter values from
 ** a [prepared statement].  The first argument is the prepared statement
 ** object to be interrogated.  The second argument
-** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
-** to be interrogated. 
-** The current value of the requested counter is returned.
-** If the resetFlg is true, then the counter is reset to zero after this
+** is an integer code for a specific [SQLITE_STMTSTATUS counter]
+** to be interrogated.)^
+** ^The current value of the requested counter is returned.
+** ^If the resetFlg is true, then the counter is reset to zero after this
 ** interface call returns.
 **
 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
 */
-SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
 
 /*
-** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550>
-** EXPERIMENTAL
+** CAPI3REF: Status Parameters for prepared statements
+** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
 **
 ** These preprocessor macros define integer codes that name counter
 ** values associated with the [sqlite3_stmt_status()] interface.
 ** The meanings of the various counters are as follows:
 **
 ** <dl>
-** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
-** <dd>This is the number of times that SQLite has stepped forward in
+** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
+** <dd>^This is the number of times that SQLite has stepped forward in
 ** a table as part of a full table scan.  Large numbers for this counter
 ** may indicate opportunities for performance improvement through 
 ** careful use of indices.</dd>
 **
-** <dt>SQLITE_STMTSTATUS_SORT</dt>
-** <dd>This is the number of sort operations that have occurred.
+** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
+** <dd>^This is the number of sort operations that have occurred.
 ** A non-zero value in this counter may indicate an opportunity to
 ** improvement performance through careful use of indices.</dd>
 **
+** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
+** <dd>^This is the number of rows inserted into transient indices that
+** were created automatically in order to help joins run faster.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance by adding permanent indices that do not
+** need to be reinitialized each time the statement is run.</dd>
 ** </dl>
 */
 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
 #define SQLITE_STMTSTATUS_SORT              2
+#define SQLITE_STMTSTATUS_AUTOINDEX         3
 
 /*
 ** CAPI3REF: Custom Page Cache Object
-** EXPERIMENTAL
 **
 ** The sqlite3_pcache type is opaque.  It is implemented by
 ** the pluggable module.  The SQLite core has no knowledge of
@@ -7091,110 +6746,164 @@ SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int
 ** sqlite3_pcache object except by holding and passing pointers
 ** to the object.
 **
-** See [sqlite3_pcache_methods] for additional information.
+** See [sqlite3_pcache_methods2] for additional information.
 */
 typedef struct sqlite3_pcache sqlite3_pcache;
 
 /*
-** CAPI3REF: Application Defined Page Cache.
-** EXPERIMENTAL
+** CAPI3REF: Custom Page Cache Object
 **
-** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
+** The sqlite3_pcache_page object represents a single page in the
+** page cache.  The page cache will allocate instances of this
+** object.  Various methods of the page cache use pointers to instances
+** of this object as parameters or as their return value.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache_page sqlite3_pcache_page;
+struct sqlite3_pcache_page {
+  void *pBuf;        /* The content of the page */
+  void *pExtra;      /* Extra information associated with the page */
+};
+
+/*
+** CAPI3REF: Application Defined Page Cache.
+** KEYWORDS: {page cache}
+**
+** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
 ** register an alternative page cache implementation by passing in an 
-** instance of the sqlite3_pcache_methods structure. The majority of the 
-** heap memory used by sqlite is used by the page cache to cache data read 
-** from, or ready to be written to, the database file. By implementing a 
-** custom page cache using this API, an application can control more 
-** precisely the amount of memory consumed by sqlite, the way in which 
-** said memory is allocated and released, and the policies used to 
+** instance of the sqlite3_pcache_methods2 structure.)^
+** In many applications, most of the heap memory allocated by 
+** SQLite is used for the page cache.
+** By implementing a 
+** custom page cache using this API, an application can better control
+** the amount of memory consumed by SQLite, the way in which 
+** that memory is allocated and released, and the policies used to 
 ** determine exactly which parts of a database file are cached and for 
 ** how long.
 **
-** The contents of the structure are copied to an internal buffer by sqlite
-** within the call to [sqlite3_config].
+** The alternative page cache mechanism is an
+** extreme measure that is only needed by the most demanding applications.
+** The built-in page cache is recommended for most uses.
 **
-** The xInit() method is called once for each call to [sqlite3_initialize()]
-** (usually only once during the lifetime of the process). It is passed
-** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set
-** up global structures and mutexes required by the custom page cache 
-** implementation. The xShutdown() method is called from within 
-** [sqlite3_shutdown()], if the application invokes this API. It can be used
-** to clean up any outstanding resources before process shutdown, if required.
+** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
+** internal buffer by SQLite within the call to [sqlite3_config].  Hence
+** the application may discard the parameter after the call to
+** [sqlite3_config()] returns.)^
 **
-** The xCreate() method is used to construct a new cache instance. The
+** [[the xInit() page cache method]]
+** ^(The xInit() method is called once for each effective 
+** call to [sqlite3_initialize()])^
+** (usually only once during the lifetime of the process). ^(The xInit()
+** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
+** The intent of the xInit() method is to set up global data structures 
+** required by the custom page cache implementation. 
+** ^(If the xInit() method is NULL, then the 
+** built-in default page cache is used instead of the application defined
+** page cache.)^
+**
+** [[the xShutdown() page cache method]]
+** ^The xShutdown() method is called by [sqlite3_shutdown()].
+** It can be used to clean up 
+** any outstanding resources before process shutdown, if required.
+** ^The xShutdown() method may be NULL.
+**
+** ^SQLite automatically serializes calls to the xInit method,
+** so the xInit method need not be threadsafe.  ^The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  All other methods must be threadsafe
+** in multithreaded applications.
+**
+** ^SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+**
+** [[the xCreate() page cache methods]]
+** ^SQLite invokes the xCreate() method to construct a new cache instance.
+** SQLite will typically create one cache instance for each open database file,
+** though this is not guaranteed. ^The
 ** first parameter, szPage, is the size in bytes of the pages that must
-** be allocated by the cache. szPage will not be a power of two. The
-** second argument, bPurgeable, is true if the cache being created will
-** be used to cache database pages read from a file stored on disk, or
+** be allocated by the cache.  ^szPage will always a power of two.  ^The
+** second parameter szExtra is a number of bytes of extra storage 
+** associated with each page cache entry.  ^The szExtra parameter will
+** a number less than 250.  SQLite will use the
+** extra szExtra bytes on each page to store metadata about the underlying
+** database page on disk.  The value passed into szExtra depends
+** on the SQLite version, the target platform, and how SQLite was compiled.
+** ^The third argument to xCreate(), bPurgeable, is true if the cache being
+** created will be used to cache database pages of a file stored on disk, or
 ** false if it is used for an in-memory database. The cache implementation
-** does not have to do anything special based on the value of bPurgeable,
-** it is purely advisory. 
+** does not have to do anything special based with the value of bPurgeable;
+** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
+** never invoke xUnpin() except to deliberately delete a page.
+** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
+** false will always have the "discard" flag set to true.  
+** ^Hence, a cache created with bPurgeable false will
+** never contain any unpinned pages.
 **
-** The xCachesize() method may be called at any time by SQLite to set the
+** [[the xCachesize() page cache method]]
+** ^(The xCachesize() method may be called at any time by SQLite to set the
 ** suggested maximum cache-size (number of pages stored by) the cache
 ** instance passed as the first argument. This is the value configured using
-** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter,
-** the implementation is not required to do anything special with this
-** value, it is advisory only.
+** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
+** parameter, the implementation is not required to do anything with this
+** value; it is advisory only.
 **
-** The xPagecount() method should return the number of pages currently
-** stored in the cache supplied as an argument.
+** [[the xPagecount() page cache methods]]
+** The xPagecount() method must return the number of pages currently
+** stored in the cache, both pinned and unpinned.
 ** 
-** The xFetch() method is used to fetch a page and return a pointer to it. 
-** A 'page', in this context, is a buffer of szPage bytes aligned at an
-** 8-byte boundary. The page to be fetched is determined by the key. The
-** mimimum key value is 1. After it has been retrieved using xFetch, the page 
-** is considered to be pinned.
+** [[the xFetch() page cache methods]]
+** The xFetch() method locates a page in the cache and returns a pointer to 
+** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
+** The pBuf element of the returned sqlite3_pcache_page object will be a
+** pointer to a buffer of szPage bytes used to store the content of a 
+** single database page.  The pExtra element of sqlite3_pcache_page will be
+** a pointer to the szExtra bytes of extra storage that SQLite has requested
+** for each entry in the page cache.
 **
-** If the requested page is already in the page cache, then a pointer to
-** the cached buffer should be returned with its contents intact. If the
-** page is not already in the cache, then the expected behaviour of the
-** cache is determined by the value of the createFlag parameter passed
-** to xFetch, according to the following table:
+** The page to be fetched is determined by the key. ^The minimum key value
+** is 1.  After it has been retrieved using xFetch, the page is considered
+** to be "pinned".
+**
+** If the requested page is already in the page cache, then the page cache
+** implementation must return a pointer to the page buffer with its content
+** intact.  If the requested page is not already in the cache, then the
+** cache implementation should use the value of the createFlag
+** parameter to help it determined what action to take:
 **
 ** <table border=1 width=85% align=center>
-**   <tr><th>createFlag<th>Expected Behaviour
-**   <tr><td>0<td>NULL should be returned. No new cache entry is created.
-**   <tr><td>1<td>If createFlag is set to 1, this indicates that 
-**                SQLite is holding pinned pages that can be unpinned
-**                by writing their contents to the database file (a
-**                relatively expensive operation). In this situation the
-**                cache implementation has two choices: it can return NULL,
-**                in which case SQLite will attempt to unpin one or more 
-**                pages before re-requesting the same page, or it can
-**                allocate a new page and return a pointer to it. If a new
-**                page is allocated, then it must be completely zeroed before 
-**                it is returned.
-**   <tr><td>2<td>If createFlag is set to 2, then SQLite is not holding any
-**                pinned pages associated with the specific cache passed
-**                as the first argument to xFetch() that can be unpinned. The
-**                cache implementation should attempt to allocate a new
-**                cache entry and return a pointer to it. Again, the new
-**                page should be zeroed before it is returned. If the xFetch()
-**                method returns NULL when createFlag==2, SQLite assumes that
-**                a memory allocation failed and returns SQLITE_NOMEM to the
-**                user.
+** <tr><th> createFlag <th> Behaviour when page is not already in cache
+** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
+** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
+**                 Otherwise return NULL.
+** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
+**                 NULL if allocating a new page is effectively impossible.
 ** </table>
 **
-** xUnpin() is called by SQLite with a pointer to a currently pinned page
-** as its second argument. If the third parameter, discard, is non-zero,
-** then the page should be evicted from the cache. In this case SQLite 
-** assumes that the next time the page is retrieved from the cache using
-** the xFetch() method, it will be zeroed. If the discard parameter is
-** zero, then the page is considered to be unpinned. The cache implementation
-** may choose to reclaim (free or recycle) unpinned pages at any time.
-** SQLite assumes that next time the page is retrieved from the cache
-** it will either be zeroed, or contain the same data that it did when it
-** was unpinned.
+** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
+** will only use a createFlag of 2 after a prior call with a createFlag of 1
+** failed.)^  In between the to xFetch() calls, SQLite may
+** attempt to unpin one or more cache pages by spilling the content of
+** pinned pages to disk and synching the operating system disk cache.
 **
-** The cache is not required to perform any reference counting. A single 
+** [[the xUnpin() page cache method]]
+** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
+** as its second argument.  If the third parameter, discard, is non-zero,
+** then the page must be evicted from the cache.
+** ^If the discard parameter is
+** zero, then the page may be discarded or retained at the discretion of
+** page cache implementation. ^The page cache implementation
+** may choose to evict unpinned pages at any time.
+**
+** The cache must not perform any reference counting. A single 
 ** call to xUnpin() unpins the page regardless of the number of prior calls 
 ** to xFetch().
 **
+** [[the xRekey() page cache methods]]
 ** The xRekey() method is used to change the key value associated with the
-** page passed as the second argument from oldKey to newKey. If the cache
-** previously contains an entry associated with newKey, it should be
-** discarded. Any prior cache entry associated with newKey is guaranteed not
+** page passed as the second argument. If the cache
+** previously contains an entry associated with newKey, it must be
+** discarded. ^Any prior cache entry associated with newKey is guaranteed not
 ** to be pinned.
 **
 ** When SQLite calls the xTruncate() method, the cache must discard all
@@ -7203,11 +6912,41 @@ typedef struct sqlite3_pcache sqlite3_pcache;
 ** of these pages are pinned, they are implicitly unpinned, meaning that
 ** they can be safely discarded.
 **
-** The xDestroy() method is used to delete a cache allocated by xCreate().
-** All resources associated with the specified cache should be freed. After
+** [[the xDestroy() page cache method]]
+** ^The xDestroy() method is used to delete a cache allocated by xCreate().
+** All resources associated with the specified cache should be freed. ^After
 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
-** handle invalid, and will not use it with any other sqlite3_pcache_methods
+** handle invalid, and will not use it with any other sqlite3_pcache_methods2
 ** functions.
+**
+** [[the xShrink() page cache method]]
+** ^SQLite invokes the xShrink() method when it wants the page cache to
+** free up as much of heap memory as possible.  The page cache implementation
+** is not obligated to free any memory, but well-behaved implementations should
+** do their best.
+*/
+typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
+struct sqlite3_pcache_methods2 {
+  int iVersion;
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
+  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 
+      unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+  void (*xShrink)(sqlite3_pcache*);
+};
+
+/*
+** This is the obsolete pcache_methods object that has now been replaced
+** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
+** retained in the header file for backwards compatibility only.
 */
 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
 struct sqlite3_pcache_methods {
@@ -7224,6 +6963,631 @@ struct sqlite3_pcache_methods {
   void (*xDestroy)(sqlite3_pcache*);
 };
 
+
+/*
+** CAPI3REF: Online Backup Object
+**
+** The sqlite3_backup object records state information about an ongoing
+** online backup operation.  ^The sqlite3_backup object is created by
+** a call to [sqlite3_backup_init()] and is destroyed by a call to
+** [sqlite3_backup_finish()].
+**
+** See Also: [Using the SQLite Online Backup API]
+*/
+typedef struct sqlite3_backup sqlite3_backup;
+
+/*
+** CAPI3REF: Online Backup API.
+**
+** The backup API copies the content of one database into another.
+** It is useful either for creating backups of databases or
+** for copying in-memory databases to or from persistent files. 
+**
+** See Also: [Using the SQLite Online Backup API]
+**
+** ^SQLite holds a write transaction open on the destination database file
+** for the duration of the backup operation.
+** ^The source database is read-locked only while it is being read;
+** it is not locked continuously for the entire backup operation.
+** ^Thus, the backup may be performed on a live source database without
+** preventing other database connections from
+** reading or writing to the source database while the backup is underway.
+** 
+** ^(To perform a backup operation: 
+**   <ol>
+**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
+**         backup, 
+**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 
+**         the data between the two databases, and finally
+**     <li><b>sqlite3_backup_finish()</b> is called to release all resources 
+**         associated with the backup operation. 
+**   </ol>)^
+** There should be exactly one call to sqlite3_backup_finish() for each
+** successful call to sqlite3_backup_init().
+**
+** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
+**
+** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 
+** [database connection] associated with the destination database 
+** and the database name, respectively.
+** ^The database name is "main" for the main database, "temp" for the
+** temporary database, or the name specified after the AS keyword in
+** an [ATTACH] statement for an attached database.
+** ^The S and M arguments passed to 
+** sqlite3_backup_init(D,N,S,M) identify the [database connection]
+** and database name of the source database, respectively.
+** ^The source and destination [database connections] (parameters S and D)
+** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
+** an error.
+**
+** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
+** returned and an error code and error message are stored in the
+** destination [database connection] D.
+** ^The error code and message for the failed call to sqlite3_backup_init()
+** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
+** [sqlite3_errmsg16()] functions.
+** ^A successful call to sqlite3_backup_init() returns a pointer to an
+** [sqlite3_backup] object.
+** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
+** sqlite3_backup_finish() functions to perform the specified backup 
+** operation.
+**
+** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
+**
+** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 
+** the source and destination databases specified by [sqlite3_backup] object B.
+** ^If N is negative, all remaining source pages are copied. 
+** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
+** are still more pages to be copied, then the function returns [SQLITE_OK].
+** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
+** from source to destination, then it returns [SQLITE_DONE].
+** ^If an error occurs while running sqlite3_backup_step(B,N),
+** then an [error code] is returned. ^As well as [SQLITE_OK] and
+** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
+** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
+**
+** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
+** <ol>
+** <li> the destination database was opened read-only, or
+** <li> the destination database is using write-ahead-log journaling
+** and the destination and source page sizes differ, or
+** <li> the destination database is an in-memory database and the
+** destination and source page sizes differ.
+** </ol>)^
+**
+** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
+** the [sqlite3_busy_handler | busy-handler function]
+** is invoked (if one is specified). ^If the 
+** busy-handler returns non-zero before the lock is available, then 
+** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
+** sqlite3_backup_step() can be retried later. ^If the source
+** [database connection]
+** is being used to write to the source database when sqlite3_backup_step()
+** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
+** case the call to sqlite3_backup_step() can be retried later on. ^(If
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
+** [SQLITE_READONLY] is returned, then 
+** there is no point in retrying the call to sqlite3_backup_step(). These 
+** errors are considered fatal.)^  The application must accept 
+** that the backup operation has failed and pass the backup operation handle 
+** to the sqlite3_backup_finish() to release associated resources.
+**
+** ^The first call to sqlite3_backup_step() obtains an exclusive lock
+** on the destination file. ^The exclusive lock is not released until either 
+** sqlite3_backup_finish() is called or the backup operation is complete 
+** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
+** sqlite3_backup_step() obtains a [shared lock] on the source database that
+** lasts for the duration of the sqlite3_backup_step() call.
+** ^Because the source database is not locked between calls to
+** sqlite3_backup_step(), the source database may be modified mid-way
+** through the backup process.  ^If the source database is modified by an
+** external process or via a database connection other than the one being
+** used by the backup operation, then the backup will be automatically
+** restarted by the next call to sqlite3_backup_step(). ^If the source 
+** database is modified by the using the same database connection as is used
+** by the backup operation, then the backup database is automatically
+** updated at the same time.
+**
+** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
+**
+** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 
+** application wishes to abandon the backup operation, the application
+** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
+** ^The sqlite3_backup_finish() interfaces releases all
+** resources associated with the [sqlite3_backup] object. 
+** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
+** active write-transaction on the destination database is rolled back.
+** The [sqlite3_backup] object is invalid
+** and may not be used following a call to sqlite3_backup_finish().
+**
+** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
+** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() completed.
+** ^If an out-of-memory condition or IO error occurred during any prior
+** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
+** sqlite3_backup_finish() returns the corresponding [error code].
+**
+** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
+** is not a permanent error and does not affect the return value of
+** sqlite3_backup_finish().
+**
+** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
+** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
+**
+** ^Each call to sqlite3_backup_step() sets two values inside
+** the [sqlite3_backup] object: the number of pages still to be backed
+** up and the total number of pages in the source database file.
+** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
+** retrieve these two values, respectively.
+**
+** ^The values returned by these functions are only updated by
+** sqlite3_backup_step(). ^If the source database is modified during a backup
+** operation, then the values are not updated to account for any extra
+** pages that need to be updated or the size of the source database file
+** changing.
+**
+** <b>Concurrent Usage of Database Handles</b>
+**
+** ^The source [database connection] may be used by the application for other
+** purposes while a backup operation is underway or being initialized.
+** ^If SQLite is compiled and configured to support threadsafe database
+** connections, then the source database connection may be used concurrently
+** from within other threads.
+**
+** However, the application must guarantee that the destination 
+** [database connection] is not passed to any other API (by any thread) after 
+** sqlite3_backup_init() is called and before the corresponding call to
+** sqlite3_backup_finish().  SQLite does not currently check to see
+** if the application incorrectly accesses the destination [database connection]
+** and so no error code is reported, but the operations may malfunction
+** nevertheless.  Use of the destination database connection while a
+** backup is in progress might also also cause a mutex deadlock.
+**
+** If running in [shared cache mode], the application must
+** guarantee that the shared cache used by the destination database
+** is not accessed while the backup is running. In practice this means
+** that the application must guarantee that the disk file being 
+** backed up to is not accessed by any connection within the process,
+** not just the specific connection that was passed to sqlite3_backup_init().
+**
+** The [sqlite3_backup] object itself is partially threadsafe. Multiple 
+** threads may safely make multiple concurrent calls to sqlite3_backup_step().
+** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
+** APIs are not strictly speaking threadsafe. If they are invoked at the
+** same time as another thread is invoking sqlite3_backup_step() it is
+** possible that they return invalid values.
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3 *pDest,                        /* Destination database handle */
+  const char *zDestName,                 /* Destination database name */
+  sqlite3 *pSource,                      /* Source database handle */
+  const char *zSourceName                /* Source database name */
+);
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
+
+/*
+** CAPI3REF: Unlock Notification
+**
+** ^When running in shared-cache mode, a database operation may fail with
+** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
+** individual tables within the shared-cache cannot be obtained. See
+** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 
+** ^This API may be used to register a callback that SQLite will invoke 
+** when the connection currently holding the required lock relinquishes it.
+** ^This API is only available if the library was compiled with the
+** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
+**
+** See Also: [Using the SQLite Unlock Notification Feature].
+**
+** ^Shared-cache locks are released when a database connection concludes
+** its current transaction, either by committing it or rolling it back. 
+**
+** ^When a connection (known as the blocked connection) fails to obtain a
+** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
+** identity of the database connection (the blocking connection) that
+** has locked the required resource is stored internally. ^After an 
+** application receives an SQLITE_LOCKED error, it may call the
+** sqlite3_unlock_notify() method with the blocked connection handle as 
+** the first argument to register for a callback that will be invoked
+** when the blocking connections current transaction is concluded. ^The
+** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
+** call that concludes the blocking connections transaction.
+**
+** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
+** there is a chance that the blocking connection will have already
+** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
+** If this happens, then the specified callback is invoked immediately,
+** from within the call to sqlite3_unlock_notify().)^
+**
+** ^If the blocked connection is attempting to obtain a write-lock on a
+** shared-cache table, and more than one other connection currently holds
+** a read-lock on the same table, then SQLite arbitrarily selects one of 
+** the other connections to use as the blocking connection.
+**
+** ^(There may be at most one unlock-notify callback registered by a 
+** blocked connection. If sqlite3_unlock_notify() is called when the
+** blocked connection already has a registered unlock-notify callback,
+** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
+** called with a NULL pointer as its second argument, then any existing
+** unlock-notify callback is canceled. ^The blocked connections 
+** unlock-notify callback may also be canceled by closing the blocked
+** connection using [sqlite3_close()].
+**
+** The unlock-notify callback is not reentrant. If an application invokes
+** any sqlite3_xxx API functions from within an unlock-notify callback, a
+** crash or deadlock may be the result.
+**
+** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
+** returns SQLITE_OK.
+**
+** <b>Callback Invocation Details</b>
+**
+** When an unlock-notify callback is registered, the application provides a 
+** single void* pointer that is passed to the callback when it is invoked.
+** However, the signature of the callback function allows SQLite to pass
+** it an array of void* context pointers. The first argument passed to
+** an unlock-notify callback is a pointer to an array of void* pointers,
+** and the second is the number of entries in the array.
+**
+** When a blocking connections transaction is concluded, there may be
+** more than one blocked connection that has registered for an unlock-notify
+** callback. ^If two or more such blocked connections have specified the
+** same callback function, then instead of invoking the callback function
+** multiple times, it is invoked once with the set of void* context pointers
+** specified by the blocked connections bundled together into an array.
+** This gives the application an opportunity to prioritize any actions 
+** related to the set of unblocked database connections.
+**
+** <b>Deadlock Detection</b>
+**
+** Assuming that after registering for an unlock-notify callback a 
+** database waits for the callback to be issued before taking any further
+** action (a reasonable assumption), then using this API may cause the
+** application to deadlock. For example, if connection X is waiting for
+** connection Y's transaction to be concluded, and similarly connection
+** Y is waiting on connection X's transaction, then neither connection
+** will proceed and the system may remain deadlocked indefinitely.
+**
+** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
+** detection. ^If a given call to sqlite3_unlock_notify() would put the
+** system in a deadlocked state, then SQLITE_LOCKED is returned and no
+** unlock-notify callback is registered. The system is said to be in
+** a deadlocked state if connection A has registered for an unlock-notify
+** callback on the conclusion of connection B's transaction, and connection
+** B has itself registered for an unlock-notify callback when connection
+** A's transaction is concluded. ^Indirect deadlock is also detected, so
+** the system is also considered to be deadlocked if connection B has
+** registered for an unlock-notify callback on the conclusion of connection
+** C's transaction, where connection C is waiting on connection A. ^Any
+** number of levels of indirection are allowed.
+**
+** <b>The "DROP TABLE" Exception</b>
+**
+** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 
+** always appropriate to call sqlite3_unlock_notify(). There is however,
+** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
+** SQLite checks if there are any currently executing SELECT statements
+** that belong to the same connection. If there are, SQLITE_LOCKED is
+** returned. In this case there is no "blocking connection", so invoking
+** sqlite3_unlock_notify() results in the unlock-notify callback being
+** invoked immediately. If the application then re-attempts the "DROP TABLE"
+** or "DROP INDEX" query, an infinite loop might be the result.
+**
+** One way around this problem is to check the extended error code returned
+** by an sqlite3_step() call. ^(If there is a blocking connection, then the
+** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
+** the special "DROP TABLE/INDEX" case, the extended error code is just 
+** SQLITE_LOCKED.)^
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *pBlocked,                          /* Waiting connection */
+  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
+  void *pNotifyArg                            /* Argument to pass to xNotify */
+);
+
+
+/*
+** CAPI3REF: String Comparison
+**
+** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
+** and extensions to compare the contents of two buffers containing UTF-8
+** strings in a case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *, const char *);
+SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
+
+/*
+** CAPI3REF: Error Logging Interface
+**
+** ^The [sqlite3_log()] interface writes a message into the error log
+** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
+** ^If logging is enabled, the zFormat string and subsequent arguments are
+** used with [sqlite3_snprintf()] to generate the final output string.
+**
+** The sqlite3_log() interface is intended for use by extensions such as
+** virtual tables, collating functions, and SQL functions.  While there is
+** nothing to prevent an application from calling sqlite3_log(), doing so
+** is considered bad form.
+**
+** The zFormat string must not be NULL.
+**
+** To avoid deadlocks and other threading problems, the sqlite3_log() routine
+** will not use dynamically allocated memory.  The log message is stored in
+** a fixed-length buffer on the stack.  If the log message is longer than
+** a few hundred characters, it will be truncated to the length of the
+** buffer.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
+
+/*
+** CAPI3REF: Write-Ahead Log Commit Hook
+**
+** ^The [sqlite3_wal_hook()] function is used to register a callback that
+** will be invoked each time a database connection commits data to a
+** [write-ahead log] (i.e. whenever a transaction is committed in
+** [journal_mode | journal_mode=WAL mode]). 
+**
+** ^The callback is invoked by SQLite after the commit has taken place and 
+** the associated write-lock on the database released, so the implementation 
+** may read, write or [checkpoint] the database as required.
+**
+** ^The first parameter passed to the callback function when it is invoked
+** is a copy of the third parameter passed to sqlite3_wal_hook() when
+** registering the callback. ^The second is a copy of the database handle.
+** ^The third parameter is the name of the database that was written to -
+** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
+** is the number of pages currently in the write-ahead log file,
+** including those that were just committed.
+**
+** The callback function should normally return [SQLITE_OK].  ^If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to report an error, though the commit will have still occurred. If the
+** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
+** that does not correspond to any valid SQLite error code, the results
+** are undefined.
+**
+** A single database handle may have at most a single write-ahead log callback 
+** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
+** previously registered write-ahead log callback. ^Note that the
+** [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
+** those overwrite any prior [sqlite3_wal_hook()] settings.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3*, 
+  int(*)(void *,sqlite3*,const char*,int),
+  void*
+);
+
+/*
+** CAPI3REF: Configure an auto-checkpoint
+**
+** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
+** [sqlite3_wal_hook()] that causes any database on [database connection] D
+** to automatically [checkpoint]
+** after committing a transaction if there are N or
+** more frames in the [write-ahead log] file.  ^Passing zero or 
+** a negative value as the nFrame parameter disables automatic
+** checkpoints entirely.
+**
+** ^The callback registered by this function replaces any existing callback
+** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
+** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
+** configured by this function.
+**
+** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
+** from SQL.
+**
+** ^Every new [database connection] defaults to having the auto-checkpoint
+** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
+** pages.  The use of this interface
+** is only necessary if the default setting is found to be suboptimal
+** for a particular application.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Checkpoint a database
+**
+** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
+** on [database connection] D to be [checkpointed].  ^If X is NULL or an
+** empty string, then a checkpoint is run on all databases of
+** connection D.  ^If the database connection D is not in
+** [WAL | write-ahead log mode] then this interface is a harmless no-op.
+**
+** ^The [wal_checkpoint pragma] can be used to invoke this interface
+** from SQL.  ^The [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] can be used to cause this interface to be
+** run whenever the WAL reaches a certain size threshold.
+**
+** See also: [sqlite3_wal_checkpoint_v2()]
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Checkpoint a database
+**
+** Run a checkpoint operation on WAL database zDb attached to database 
+** handle db. The specific operation is determined by the value of the 
+** eMode parameter:
+**
+** <dl>
+** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
+**   Checkpoint as many frames as possible without waiting for any database 
+**   readers or writers to finish. Sync the db file if all frames in the log
+**   are checkpointed. This mode is the same as calling 
+**   sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
+**
+** <dt>SQLITE_CHECKPOINT_FULL<dd>
+**   This mode blocks (calls the busy-handler callback) until there is no
+**   database writer and all readers are reading from the most recent database
+**   snapshot. It then checkpoints all frames in the log file and syncs the
+**   database file. This call blocks database writers while it is running,
+**   but not database readers.
+**
+** <dt>SQLITE_CHECKPOINT_RESTART<dd>
+**   This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 
+**   checkpointing the log file it blocks (calls the busy-handler callback)
+**   until all readers are reading from the database file only. This ensures 
+**   that the next client to write to the database file restarts the log file 
+**   from the beginning. This call blocks database writers while it is running,
+**   but not database readers.
+** </dl>
+**
+** If pnLog is not NULL, then *pnLog is set to the total number of frames in
+** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
+** the total number of checkpointed frames (including any that were already
+** checkpointed when this function is called). *pnLog and *pnCkpt may be
+** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
+** If no values are available because of an error, they are both set to -1
+** before returning to communicate this to the caller.
+**
+** All calls obtain an exclusive "checkpoint" lock on the database file. If
+** any other process is running a checkpoint operation at the same time, the 
+** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 
+** busy-handler configured, it will not be invoked in this case.
+**
+** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 
+** "writer" lock on the database file. If the writer lock cannot be obtained
+** immediately, and a busy-handler is configured, it is invoked and the writer
+** lock retried until either the busy-handler returns 0 or the lock is
+** successfully obtained. The busy-handler is also invoked while waiting for
+** database readers as described above. If the busy-handler returns 0 before
+** the writer lock is obtained or while waiting for database readers, the
+** checkpoint operation proceeds from that point in the same way as 
+** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 
+** without blocking any further. SQLITE_BUSY is returned in this case.
+**
+** If parameter zDb is NULL or points to a zero length string, then the
+** specified operation is attempted on all WAL databases. In this case the
+** values written to output parameters *pnLog and *pnCkpt are undefined. If 
+** an SQLITE_BUSY error is encountered when processing one or more of the 
+** attached WAL databases, the operation is still attempted on any remaining 
+** attached databases and SQLITE_BUSY is returned to the caller. If any other 
+** error occurs while processing an attached database, processing is abandoned 
+** and the error code returned to the caller immediately. If no error 
+** (SQLITE_BUSY or otherwise) is encountered while processing the attached 
+** databases, SQLITE_OK is returned.
+**
+** If database zDb is the name of an attached database that is not in WAL
+** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
+** zDb is not NULL (or a zero length string) and is not the name of any
+** attached database, SQLITE_ERROR is returned to the caller.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+);
+
+/*
+** CAPI3REF: Checkpoint operation parameters
+**
+** These constants can be used as the 3rd parameter to
+** [sqlite3_wal_checkpoint_v2()].  See the [sqlite3_wal_checkpoint_v2()]
+** documentation for additional information about the meaning and use of
+** each of these values.
+*/
+#define SQLITE_CHECKPOINT_PASSIVE 0
+#define SQLITE_CHECKPOINT_FULL    1
+#define SQLITE_CHECKPOINT_RESTART 2
+
+/*
+** CAPI3REF: Virtual Table Interface Configuration
+**
+** This function may be called by either the [xConnect] or [xCreate] method
+** of a [virtual table] implementation to configure
+** various facets of the virtual table interface.
+**
+** If this interface is invoked outside the context of an xConnect or
+** xCreate virtual table method then the behavior is undefined.
+**
+** At present, there is only one option that may be configured using
+** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
+** may be added in the future.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Virtual Table Configuration Options
+**
+** These macros define the various options to the
+** [sqlite3_vtab_config()] interface that [virtual table] implementations
+** can use to customize and optimize their behavior.
+**
+** <dl>
+** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
+** where X is an integer.  If X is zero, then the [virtual table] whose
+** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
+** support constraints.  In this configuration (which is the default) if
+** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
+** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
+** specified as part of the users SQL statement, regardless of the actual
+** ON CONFLICT mode specified.
+**
+** If X is non-zero, then the virtual table implementation guarantees
+** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
+** any modifications to internal or persistent data structures have been made.
+** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 
+** is able to roll back a statement or database transaction, and abandon
+** or continue processing the current SQL statement as appropriate. 
+** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
+** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
+** had been ABORT.
+**
+** Virtual table implementations that are required to handle OR REPLACE
+** must do so within the [xUpdate] method. If a call to the 
+** [sqlite3_vtab_on_conflict()] function indicates that the current ON 
+** CONFLICT policy is REPLACE, the virtual table implementation should 
+** silently replace the appropriate rows within the xUpdate callback and
+** return SQLITE_OK. Or, if this is not possible, it may return
+** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 
+** constraint handling.
+** </dl>
+*/
+#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
+
+/*
+** CAPI3REF: Determine The Virtual Table Conflict Policy
+**
+** This function may only be called from within a call to the [xUpdate] method
+** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
+** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
+** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
+** of the SQL statement that triggered the call to the [xUpdate] method of the
+** [virtual table].
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
+
+/*
+** CAPI3REF: Conflict resolution modes
+**
+** These constants are returned by [sqlite3_vtab_on_conflict()] to
+** inform a [virtual table] implementation what the [ON CONFLICT] mode
+** is for the SQL statement being evaluated.
+**
+** Note that the [SQLITE_IGNORE] constant is also used as a potential
+** return value from the [sqlite3_set_authorizer()] callback and that
+** [SQLITE_ABORT] is also a [result code].
+*/
+#define SQLITE_ROLLBACK 1
+/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
+#define SQLITE_FAIL     3
+/* #define SQLITE_ABORT 4  // Also an error code */
+#define SQLITE_REPLACE  5
+
+
+
 /*
 ** Undo the hack that converts floating point types to integer for
 ** builds on processors without floating point support.
@@ -7237,6 +7601,67 @@ struct sqlite3_pcache_methods {
 #endif
 #endif
 
+/*
+** 2010 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#ifndef _SQLITE3RTREE_H_
+#define _SQLITE3RTREE_H_
+
+
+#if 0
+extern "C" {
+#endif
+
+typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
+
+/*
+** Register a geometry callback named zGeom that can be used as part of an
+** R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,
+  const char *zGeom,
+#ifdef SQLITE_RTREE_INT_ONLY
+  int (*xGeom)(sqlite3_rtree_geometry*, int n, sqlite3_int64 *a, int *pRes),
+#else
+  int (*xGeom)(sqlite3_rtree_geometry*, int n, double *a, int *pRes),
+#endif
+  void *pContext
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the first
+** argument to callbacks registered using rtree_geometry_callback().
+*/
+struct sqlite3_rtree_geometry {
+  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
+  int nParam;                     /* Size of array aParam[] */
+  double *aParam;                 /* Parameters passed to SQL geom function */
+  void *pUser;                    /* Callback implementation user data */
+  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
+};
+
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif  /* ifndef _SQLITE3RTREE_H_ */
+
+
 /************** End of sqlite3.h *********************************************/
 /************** Continuing where we left off in sqliteInt.h ******************/
 /************** Include hash.h in the middle of sqliteInt.h ******************/
@@ -7254,8 +7679,6 @@ struct sqlite3_pcache_methods {
 *************************************************************************
 ** This is the header file for the generic hash-table implemenation
 ** used in SQLite.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _SQLITE_HASH_H_
 #define _SQLITE_HASH_H_
@@ -7268,13 +7691,25 @@ typedef struct HashElem HashElem;
 ** The internals of this structure are intended to be opaque -- client
 ** code should not attempt to access or modify the fields of this structure
 ** directly.  Change this structure only by using the routines below.
-** However, many of the "procedures" and "functions" for modifying and
+** However, some of the "procedures" and "functions" for modifying and
 ** accessing this structure are really macros, so we can't really make
 ** this structure opaque.
+**
+** All elements of the hash table are on a single doubly-linked list.
+** Hash.first points to the head of this list.
+**
+** There are Hash.htsize buckets.  Each bucket points to a spot in
+** the global doubly-linked list.  The contents of the bucket are the
+** element pointed to plus the next _ht.count-1 elements in the list.
+**
+** Hash.htsize and Hash.ht may be zero.  In that case lookup is done
+** by a linear search of the global list.  For small tables, the 
+** Hash.ht table is never allocated because if there are few elements
+** in the table, it is faster to do a linear search than to manage
+** the hash table.
 */
 struct Hash {
-  unsigned int copyKey: 1;  /* True if copy of key made on insert */
-  unsigned int htsize : 31; /* Number of buckets in the hash table */
+  unsigned int htsize;      /* Number of buckets in the hash table */
   unsigned int count;       /* Number of entries in this table */
   HashElem *first;          /* The first element of the array */
   struct _ht {              /* the hash table */
@@ -7290,18 +7725,17 @@ struct Hash {
 ** be opaque because it is used by macros.
 */
 struct HashElem {
-  HashElem *next, *prev;   /* Next and previous elements in the table */
-  void *data;              /* Data associated with this element */
-  void *pKey; int nKey;    /* Key associated with this element */
+  HashElem *next, *prev;       /* Next and previous elements in the table */
+  void *data;                  /* Data associated with this element */
+  const char *pKey; int nKey;  /* Key associated with this element */
 };
 
 /*
 ** Access routines.  To delete, insert a NULL pointer.
 */
-SQLITE_PRIVATE void sqlite3HashInit(Hash*, int copyKey);
-SQLITE_PRIVATE void *sqlite3HashInsert(Hash*, const void *pKey, int nKey, void *pData);
-SQLITE_PRIVATE void *sqlite3HashFind(const Hash*, const void *pKey, int nKey);
-SQLITE_PRIVATE HashElem *sqlite3HashFindElem(const Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE void sqlite3HashInit(Hash*);
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash*, const char *pKey, int nKey, void *pData);
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash*, const char *pKey, int nKey);
 SQLITE_PRIVATE void sqlite3HashClear(Hash*);
 
 /*
@@ -7319,13 +7753,13 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash*);
 #define sqliteHashFirst(H)  ((H)->first)
 #define sqliteHashNext(E)   ((E)->next)
 #define sqliteHashData(E)   ((E)->data)
-#define sqliteHashKey(E)    ((E)->pKey)
-#define sqliteHashKeysize(E) ((E)->nKey)
+/* #define sqliteHashKey(E)    ((E)->pKey) // NOT USED */
+/* #define sqliteHashKeysize(E) ((E)->nKey)  // NOT USED */
 
 /*
 ** Number of entries in a hash table
 */
-#define sqliteHashCount(H)  ((H)->count)
+/* #define sqliteHashCount(H)  ((H)->count) // NOT USED */
 
 #endif /* _SQLITE_HASH_H_ */
 
@@ -7348,8 +7782,8 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash*);
 #define TK_SAVEPOINT                      13
 #define TK_RELEASE                        14
 #define TK_TO                             15
-#define TK_CREATE                         16
-#define TK_TABLE                          17
+#define TK_TABLE                          16
+#define TK_CREATE                         17
 #define TK_IF                             18
 #define TK_NOT                            19
 #define TK_EXISTS                         20
@@ -7359,134 +7793,137 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash*);
 #define TK_AS                             24
 #define TK_COMMA                          25
 #define TK_ID                             26
-#define TK_ABORT                          27
-#define TK_AFTER                          28
-#define TK_ANALYZE                        29
-#define TK_ASC                            30
-#define TK_ATTACH                         31
-#define TK_BEFORE                         32
-#define TK_CASCADE                        33
-#define TK_CAST                           34
-#define TK_CONFLICT                       35
-#define TK_DATABASE                       36
-#define TK_DESC                           37
-#define TK_DETACH                         38
-#define TK_EACH                           39
-#define TK_FAIL                           40
-#define TK_FOR                            41
-#define TK_IGNORE                         42
-#define TK_INITIALLY                      43
-#define TK_INSTEAD                        44
-#define TK_LIKE_KW                        45
-#define TK_MATCH                          46
-#define TK_KEY                            47
-#define TK_OF                             48
-#define TK_OFFSET                         49
-#define TK_PRAGMA                         50
-#define TK_RAISE                          51
-#define TK_REPLACE                        52
-#define TK_RESTRICT                       53
-#define TK_ROW                            54
-#define TK_TRIGGER                        55
-#define TK_VACUUM                         56
-#define TK_VIEW                           57
-#define TK_VIRTUAL                        58
-#define TK_REINDEX                        59
-#define TK_RENAME                         60
-#define TK_CTIME_KW                       61
-#define TK_ANY                            62
-#define TK_OR                             63
-#define TK_AND                            64
-#define TK_IS                             65
-#define TK_BETWEEN                        66
-#define TK_IN                             67
-#define TK_ISNULL                         68
-#define TK_NOTNULL                        69
-#define TK_NE                             70
-#define TK_EQ                             71
-#define TK_GT                             72
-#define TK_LE                             73
-#define TK_LT                             74
-#define TK_GE                             75
-#define TK_ESCAPE                         76
-#define TK_BITAND                         77
-#define TK_BITOR                          78
-#define TK_LSHIFT                         79
-#define TK_RSHIFT                         80
-#define TK_PLUS                           81
-#define TK_MINUS                          82
-#define TK_STAR                           83
-#define TK_SLASH                          84
-#define TK_REM                            85
-#define TK_CONCAT                         86
-#define TK_COLLATE                        87
-#define TK_UMINUS                         88
-#define TK_UPLUS                          89
-#define TK_BITNOT                         90
-#define TK_STRING                         91
-#define TK_JOIN_KW                        92
-#define TK_CONSTRAINT                     93
-#define TK_DEFAULT                        94
-#define TK_NULL                           95
-#define TK_PRIMARY                        96
-#define TK_UNIQUE                         97
-#define TK_CHECK                          98
-#define TK_REFERENCES                     99
-#define TK_AUTOINCR                       100
-#define TK_ON                             101
-#define TK_DELETE                         102
-#define TK_UPDATE                         103
-#define TK_INSERT                         104
-#define TK_SET                            105
-#define TK_DEFERRABLE                     106
-#define TK_FOREIGN                        107
-#define TK_DROP                           108
-#define TK_UNION                          109
-#define TK_ALL                            110
-#define TK_EXCEPT                         111
-#define TK_INTERSECT                      112
-#define TK_SELECT                         113
-#define TK_DISTINCT                       114
-#define TK_DOT                            115
-#define TK_FROM                           116
-#define TK_JOIN                           117
-#define TK_INDEXED                        118
-#define TK_BY                             119
-#define TK_USING                          120
-#define TK_ORDER                          121
-#define TK_GROUP                          122
-#define TK_HAVING                         123
-#define TK_LIMIT                          124
-#define TK_WHERE                          125
-#define TK_INTO                           126
-#define TK_VALUES                         127
-#define TK_INTEGER                        128
-#define TK_FLOAT                          129
-#define TK_BLOB                           130
-#define TK_REGISTER                       131
-#define TK_VARIABLE                       132
-#define TK_CASE                           133
-#define TK_WHEN                           134
-#define TK_THEN                           135
-#define TK_ELSE                           136
-#define TK_INDEX                          137
-#define TK_ALTER                          138
-#define TK_ADD                            139
-#define TK_COLUMNKW                       140
+#define TK_INDEXED                        27
+#define TK_ABORT                          28
+#define TK_ACTION                         29
+#define TK_AFTER                          30
+#define TK_ANALYZE                        31
+#define TK_ASC                            32
+#define TK_ATTACH                         33
+#define TK_BEFORE                         34
+#define TK_BY                             35
+#define TK_CASCADE                        36
+#define TK_CAST                           37
+#define TK_COLUMNKW                       38
+#define TK_CONFLICT                       39
+#define TK_DATABASE                       40
+#define TK_DESC                           41
+#define TK_DETACH                         42
+#define TK_EACH                           43
+#define TK_FAIL                           44
+#define TK_FOR                            45
+#define TK_IGNORE                         46
+#define TK_INITIALLY                      47
+#define TK_INSTEAD                        48
+#define TK_LIKE_KW                        49
+#define TK_MATCH                          50
+#define TK_NO                             51
+#define TK_KEY                            52
+#define TK_OF                             53
+#define TK_OFFSET                         54
+#define TK_PRAGMA                         55
+#define TK_RAISE                          56
+#define TK_REPLACE                        57
+#define TK_RESTRICT                       58
+#define TK_ROW                            59
+#define TK_TRIGGER                        60
+#define TK_VACUUM                         61
+#define TK_VIEW                           62
+#define TK_VIRTUAL                        63
+#define TK_REINDEX                        64
+#define TK_RENAME                         65
+#define TK_CTIME_KW                       66
+#define TK_ANY                            67
+#define TK_OR                             68
+#define TK_AND                            69
+#define TK_IS                             70
+#define TK_BETWEEN                        71
+#define TK_IN                             72
+#define TK_ISNULL                         73
+#define TK_NOTNULL                        74
+#define TK_NE                             75
+#define TK_EQ                             76
+#define TK_GT                             77
+#define TK_LE                             78
+#define TK_LT                             79
+#define TK_GE                             80
+#define TK_ESCAPE                         81
+#define TK_BITAND                         82
+#define TK_BITOR                          83
+#define TK_LSHIFT                         84
+#define TK_RSHIFT                         85
+#define TK_PLUS                           86
+#define TK_MINUS                          87
+#define TK_STAR                           88
+#define TK_SLASH                          89
+#define TK_REM                            90
+#define TK_CONCAT                         91
+#define TK_COLLATE                        92
+#define TK_BITNOT                         93
+#define TK_STRING                         94
+#define TK_JOIN_KW                        95
+#define TK_CONSTRAINT                     96
+#define TK_DEFAULT                        97
+#define TK_NULL                           98
+#define TK_PRIMARY                        99
+#define TK_UNIQUE                         100
+#define TK_CHECK                          101
+#define TK_REFERENCES                     102
+#define TK_AUTOINCR                       103
+#define TK_ON                             104
+#define TK_INSERT                         105
+#define TK_DELETE                         106
+#define TK_UPDATE                         107
+#define TK_SET                            108
+#define TK_DEFERRABLE                     109
+#define TK_FOREIGN                        110
+#define TK_DROP                           111
+#define TK_UNION                          112
+#define TK_ALL                            113
+#define TK_EXCEPT                         114
+#define TK_INTERSECT                      115
+#define TK_SELECT                         116
+#define TK_DISTINCT                       117
+#define TK_DOT                            118
+#define TK_FROM                           119
+#define TK_JOIN                           120
+#define TK_USING                          121
+#define TK_ORDER                          122
+#define TK_GROUP                          123
+#define TK_HAVING                         124
+#define TK_LIMIT                          125
+#define TK_WHERE                          126
+#define TK_INTO                           127
+#define TK_VALUES                         128
+#define TK_INTEGER                        129
+#define TK_FLOAT                          130
+#define TK_BLOB                           131
+#define TK_REGISTER                       132
+#define TK_VARIABLE                       133
+#define TK_CASE                           134
+#define TK_WHEN                           135
+#define TK_THEN                           136
+#define TK_ELSE                           137
+#define TK_INDEX                          138
+#define TK_ALTER                          139
+#define TK_ADD                            140
 #define TK_TO_TEXT                        141
 #define TK_TO_BLOB                        142
 #define TK_TO_NUMERIC                     143
 #define TK_TO_INT                         144
 #define TK_TO_REAL                        145
-#define TK_END_OF_FILE                    146
-#define TK_ILLEGAL                        147
-#define TK_SPACE                          148
-#define TK_UNCLOSED_STRING                149
-#define TK_FUNCTION                       150
-#define TK_COLUMN                         151
-#define TK_AGG_FUNCTION                   152
-#define TK_AGG_COLUMN                     153
-#define TK_CONST_FUNC                     154
+#define TK_ISNOT                          146
+#define TK_END_OF_FILE                    147
+#define TK_ILLEGAL                        148
+#define TK_SPACE                          149
+#define TK_UNCLOSED_STRING                150
+#define TK_FUNCTION                       151
+#define TK_COLUMN                         152
+#define TK_AGG_FUNCTION                   153
+#define TK_AGG_COLUMN                     154
+#define TK_CONST_FUNC                     155
+#define TK_UMINUS                         156
+#define TK_UPLUS                          157
 
 /************** End of parse.h ***********************************************/
 /************** Continuing where we left off in sqliteInt.h ******************/
@@ -7502,13 +7939,15 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash*);
 */
 #ifdef SQLITE_OMIT_FLOATING_POINT
 # define double sqlite_int64
+# define float sqlite_int64
 # define LONGDOUBLE_TYPE sqlite_int64
 # ifndef SQLITE_BIG_DBL
-#   define SQLITE_BIG_DBL (0x7fffffffffffffff)
+#   define SQLITE_BIG_DBL (((sqlite3_int64)1)<<50)
 # endif
 # define SQLITE_OMIT_DATETIME_FUNCS 1
 # define SQLITE_OMIT_TRACE 1
 # undef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+# undef SQLITE_HAVE_ISNAN
 #endif
 #ifndef SQLITE_BIG_DBL
 # define SQLITE_BIG_DBL (1e99)
@@ -7525,20 +7964,6 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash*);
 #define OMIT_TEMPDB 0
 #endif
 
-/*
-** If the following macro is set to 1, then NULL values are considered
-** distinct when determining whether or not two entries are the same
-** in a UNIQUE index.  This is the way PostgreSQL, Oracle, DB2, MySQL,
-** OCELOT, and Firebird all work.  The SQL92 spec explicitly says this
-** is the way things are suppose to work.
-**
-** If the following macro is set to 0, the NULLs are indistinct for
-** a UNIQUE index.  In this mode, you can only have a single NULL entry
-** for a column declared UNIQUE.  This is the way Informix and SQL Server
-** work.
-*/
-#define NULL_DISTINCT_FOR_UNIQUE 1
-
 /*
 ** The "file format" number is an integer that is incremented whenever
 ** the VDBE-level file format changes.  The following macros define the
@@ -7547,7 +7972,15 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash*);
 */
 #define SQLITE_MAX_FILE_FORMAT 4
 #ifndef SQLITE_DEFAULT_FILE_FORMAT
-# define SQLITE_DEFAULT_FILE_FORMAT 1
+# define SQLITE_DEFAULT_FILE_FORMAT 4
+#endif
+
+/*
+** Determine whether triggers are recursive by default.  This can be
+** changed at run-time using a pragma.
+*/
+#ifndef SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+# define SQLITE_DEFAULT_RECURSIVE_TRIGGERS 0
 #endif
 
 /*
@@ -7629,6 +8062,26 @@ typedef INT16_TYPE i16;            /* 2-byte signed integer */
 typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
 typedef INT8_TYPE i8;              /* 1-byte signed integer */
 
+/*
+** SQLITE_MAX_U32 is a u64 constant that is the maximum u64 value
+** that can be stored in a u32 without loss of data.  The value
+** is 0x00000000ffffffff.  But because of quirks of some compilers, we
+** have to specify the value in the less intuitive manner shown:
+*/
+#define SQLITE_MAX_U32  ((((u64)1)<<32)-1)
+
+/*
+** The datatype used to store estimates of the number of rows in a
+** table or index.  This is an unsigned integer type.  For 99.9% of
+** the world, a 32-bit integer is sufficient.  But a 64-bit integer
+** can be used at compile-time if desired.
+*/
+#ifdef SQLITE_64BIT_STATS
+ typedef u64 tRowcnt;    /* 64-bit only if requested at compile-time */
+#else
+ typedef u32 tRowcnt;    /* 32-bit is the default */
+#endif
+
 /*
 ** Macros to determine whether the machine is big or little endian,
 ** evaluated at runtime.
@@ -7657,6 +8110,33 @@ SQLITE_PRIVATE const int sqlite3one;
 #define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
 #define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
 
+/* 
+** Round up a number to the next larger multiple of 8.  This is used
+** to force 8-byte alignment on 64-bit architectures.
+*/
+#define ROUND8(x)     (((x)+7)&~7)
+
+/*
+** Round down to the nearest multiple of 8
+*/
+#define ROUNDDOWN8(x) ((x)&~7)
+
+/*
+** Assert that the pointer X is aligned to an 8-byte boundary.  This
+** macro is used only within assert() to verify that the code gets
+** all alignment restrictions correct.
+**
+** Except, if SQLITE_4_BYTE_ALIGNED_MALLOC is defined, then the
+** underlying malloc() implemention might return us 4-byte aligned
+** pointers.  In that case, only verify 4-byte alignment.
+*/
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((char*)(X) - (char*)0)&3)==0)
+#else
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((char*)(X) - (char*)0)&7)==0)
+#endif
+
+
 /*
 ** An instance of the following structure is used to store the busy-handler
 ** callback for a given sqlite handle. 
@@ -7699,9 +8179,13 @@ struct BusyHandler {
 
 /*
 ** The following value as a destructor means to use sqlite3DbFree().
-** This is an internal extension to SQLITE_STATIC and SQLITE_TRANSIENT.
+** The sqlite3DbFree() routine requires two parameters instead of the 
+** one parameter that destructors normally want.  So we have to introduce 
+** this magic value that the code knows to handle differently.  Any 
+** pointer will work here as long as it is distinct from SQLITE_STATIC
+** and SQLITE_TRANSIENT.
 */
-#define SQLITE_DYNAMIC   ((sqlite3_destructor_type)sqlite3DbFree)
+#define SQLITE_DYNAMIC   ((sqlite3_destructor_type)sqlite3MallocSize)
 
 /*
 ** When SQLITE_OMIT_WSD is defined, it means that the target platform does
@@ -7753,19 +8237,22 @@ SQLITE_API   void *sqlite3_wsd_find(void *K, int L);
 */
 typedef struct AggInfo AggInfo;
 typedef struct AuthContext AuthContext;
+typedef struct AutoincInfo AutoincInfo;
 typedef struct Bitvec Bitvec;
-typedef struct RowSet RowSet;
 typedef struct CollSeq CollSeq;
 typedef struct Column Column;
 typedef struct Db Db;
 typedef struct Schema Schema;
 typedef struct Expr Expr;
 typedef struct ExprList ExprList;
+typedef struct ExprSpan ExprSpan;
 typedef struct FKey FKey;
+typedef struct FuncDestructor FuncDestructor;
 typedef struct FuncDef FuncDef;
 typedef struct FuncDefHash FuncDefHash;
 typedef struct IdList IdList;
 typedef struct Index Index;
+typedef struct IndexSample IndexSample;
 typedef struct KeyClass KeyClass;
 typedef struct KeyInfo KeyInfo;
 typedef struct Lookaside Lookaside;
@@ -7773,6 +8260,7 @@ typedef struct LookasideSlot LookasideSlot;
 typedef struct Module Module;
 typedef struct NameContext NameContext;
 typedef struct Parse Parse;
+typedef struct RowSet RowSet;
 typedef struct Savepoint Savepoint;
 typedef struct Select Select;
 typedef struct SrcList SrcList;
@@ -7780,10 +8268,12 @@ typedef struct StrAccum StrAccum;
 typedef struct Table Table;
 typedef struct TableLock TableLock;
 typedef struct Token Token;
-typedef struct TriggerStack TriggerStack;
-typedef struct TriggerStep TriggerStep;
 typedef struct Trigger Trigger;
+typedef struct TriggerPrg TriggerPrg;
+typedef struct TriggerStep TriggerStep;
 typedef struct UnpackedRecord UnpackedRecord;
+typedef struct VTable VTable;
+typedef struct VtabCtx VtabCtx;
 typedef struct Walker Walker;
 typedef struct WherePlan WherePlan;
 typedef struct WhereInfo WhereInfo;
@@ -7810,8 +8300,6 @@ typedef struct WhereLevel WhereLevel;
 ** This header file defines the interface that the sqlite B-Tree file
 ** subsystem.  See comments in the source code for a detailed description
 ** of what each interface routine does.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _BTREE_H_
 #define _BTREE_H_
@@ -7839,24 +8327,13 @@ typedef struct WhereLevel WhereLevel;
 typedef struct Btree Btree;
 typedef struct BtCursor BtCursor;
 typedef struct BtShared BtShared;
-typedef struct BtreeMutexArray BtreeMutexArray;
-
-/*
-** This structure records all of the Btrees that need to hold
-** a mutex before we enter sqlite3VdbeExec().  The Btrees are
-** are placed in aBtree[] in order of aBtree[]->pBt.  That way,
-** we can always lock and unlock them all quickly.
-*/
-struct BtreeMutexArray {
-  int nMutex;
-  Btree *aBtree[SQLITE_MAX_ATTACHED+1];
-};
 
 
 SQLITE_PRIVATE int sqlite3BtreeOpen(
+  sqlite3_vfs *pVfs,       /* VFS to use with this b-tree */
   const char *zFilename,   /* Name of database file to open */
   sqlite3 *db,             /* Associated database connection */
-  Btree **,                /* Return open Btree* here */
+  Btree **ppBtree,         /* Return open Btree* here */
   int flags,               /* Flags */
   int vfsFlags             /* Flags passed through to VFS open */
 );
@@ -7867,60 +8344,91 @@ SQLITE_PRIVATE int sqlite3BtreeOpen(
 ** NOTE:  These values must match the corresponding PAGER_ values in
 ** pager.h.
 */
-#define BTREE_OMIT_JOURNAL  1  /* Do not use journal.  No argument */
-#define BTREE_NO_READLOCK   2  /* Omit readlocks on readonly files */
-#define BTREE_MEMORY        4  /* In-memory DB.  No argument */
-#define BTREE_READONLY      8  /* Open the database in read-only mode */
-#define BTREE_READWRITE    16  /* Open for both reading and writing */
-#define BTREE_CREATE       32  /* Create the database if it does not exist */
+#define BTREE_OMIT_JOURNAL  1  /* Do not create or use a rollback journal */
+#define BTREE_MEMORY        2  /* This is an in-memory DB */
+#define BTREE_SINGLE        4  /* The file contains at most 1 b-tree */
+#define BTREE_UNORDERED     8  /* Use of a hash implementation is OK */
 
 SQLITE_PRIVATE int sqlite3BtreeClose(Btree*);
 SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree*,int);
-SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(Btree*,int,int);
+SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(Btree*,int,int,int);
 SQLITE_PRIVATE int sqlite3BtreeSyncDisabled(Btree*);
-SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree*,int,int);
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);
 SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree*);
 SQLITE_PRIVATE int sqlite3BtreeMaxPageCount(Btree*,int);
+SQLITE_PRIVATE u32 sqlite3BtreeLastPage(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree*,int);
 SQLITE_PRIVATE int sqlite3BtreeGetReserve(Btree*);
 SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *, int);
 SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *);
 SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree*,int);
 SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree*, const char *zMaster);
-SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree*, int);
 SQLITE_PRIVATE int sqlite3BtreeCommit(Btree*);
-SQLITE_PRIVATE int sqlite3BtreeRollback(Btree*);
-SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree*);
-SQLITE_PRIVATE int sqlite3BtreeCommitStmt(Btree*);
-SQLITE_PRIVATE int sqlite3BtreeRollbackStmt(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree*,int);
 SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree*, int*, int flags);
 SQLITE_PRIVATE int sqlite3BtreeIsInTrans(Btree*);
-SQLITE_PRIVATE int sqlite3BtreeIsInStmt(Btree*);
 SQLITE_PRIVATE int sqlite3BtreeIsInReadTrans(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeIsInBackup(Btree*);
 SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
-SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *);
-SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *, int, u8);
+SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *pBtree);
+SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *pBtree, int iTab, u8 isWriteLock);
 SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *, int, int);
 
 SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *);
-SQLITE_PRIVATE const char *sqlite3BtreeGetDirname(Btree *);
 SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *);
 SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *, Btree *);
 
 SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *);
 
 /* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR
-** of the following flags:
+** of the flags shown below.
+**
+** Every SQLite table must have either BTREE_INTKEY or BTREE_BLOBKEY set.
+** With BTREE_INTKEY, the table key is a 64-bit integer and arbitrary data
+** is stored in the leaves.  (BTREE_INTKEY is used for SQL tables.)  With
+** BTREE_BLOBKEY, the key is an arbitrary BLOB and no content is stored
+** anywhere - the key is the content.  (BTREE_BLOBKEY is used for SQL
+** indices.)
 */
 #define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
-#define BTREE_ZERODATA   2    /* Table has keys only - no data */
-#define BTREE_LEAFDATA   4    /* Data stored in leaves only.  Implies INTKEY */
+#define BTREE_BLOBKEY    2    /* Table has keys only - no data */
 
 SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree*, int, int*);
 SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree*, int, int*);
-SQLITE_PRIVATE int sqlite3BtreeGetMeta(Btree*, int idx, u32 *pValue);
-SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);
 SQLITE_PRIVATE void sqlite3BtreeTripAllCursors(Btree*, int);
 
+SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
+SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);
+
+/*
+** The second parameter to sqlite3BtreeGetMeta or sqlite3BtreeUpdateMeta
+** should be one of the following values. The integer values are assigned 
+** to constants so that the offset of the corresponding field in an
+** SQLite database header may be found using the following formula:
+**
+**   offset = 36 + (idx * 4)
+**
+** For example, the free-page-count field is located at byte offset 36 of
+** the database file header. The incr-vacuum-flag field is located at
+** byte offset 64 (== 36+4*7).
+*/
+#define BTREE_FREE_PAGE_COUNT     0
+#define BTREE_SCHEMA_VERSION      1
+#define BTREE_FILE_FORMAT         2
+#define BTREE_DEFAULT_CACHE_SIZE  3
+#define BTREE_LARGEST_ROOT_PAGE   4
+#define BTREE_TEXT_ENCODING       5
+#define BTREE_USER_VERSION        6
+#define BTREE_INCR_VACUUM         7
+
+/*
+** Values that may be OR'd together to form the second argument of an
+** sqlite3BtreeCursorHints() call.
+*/
+#define BTREE_BULKLOAD 0x00000001
+
 SQLITE_PRIVATE int sqlite3BtreeCursor(
   Btree*,                              /* BTree containing table to open */
   int iTable,                          /* Index of root page */
@@ -7929,15 +8437,9 @@ SQLITE_PRIVATE int sqlite3BtreeCursor(
   BtCursor *pCursor                    /* Space to write cursor structure */
 );
 SQLITE_PRIVATE int sqlite3BtreeCursorSize(void);
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor*);
 
 SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor*);
-SQLITE_PRIVATE int sqlite3BtreeMoveto(
-  BtCursor*,
-  const void *pKey,
-  i64 nKey,
-  int bias,
-  int *pRes
-);
 SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
   BtCursor*,
   UnpackedRecord *pUnKey,
@@ -7949,20 +8451,20 @@ SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor*, int*);
 SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor*);
 SQLITE_PRIVATE int sqlite3BtreeInsert(BtCursor*, const void *pKey, i64 nKey,
                                   const void *pData, int nData,
-                                  int nZero, int bias);
+                                  int nZero, int bias, int seekResult);
 SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor*, int *pRes);
 SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor*, int *pRes);
 SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor*, int *pRes);
 SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor*);
-SQLITE_PRIVATE int sqlite3BtreeFlags(BtCursor*);
 SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor*, int *pRes);
 SQLITE_PRIVATE int sqlite3BtreeKeySize(BtCursor*, i64 *pSize);
 SQLITE_PRIVATE int sqlite3BtreeKey(BtCursor*, u32 offset, u32 amt, void*);
-SQLITE_PRIVATE sqlite3 *sqlite3BtreeCursorDb(const BtCursor*);
 SQLITE_PRIVATE const void *sqlite3BtreeKeyFetch(BtCursor*, int *pAmt);
 SQLITE_PRIVATE const void *sqlite3BtreeDataFetch(BtCursor*, int *pAmt);
 SQLITE_PRIVATE int sqlite3BtreeDataSize(BtCursor*, u32 *pSize);
 SQLITE_PRIVATE int sqlite3BtreeData(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE void sqlite3BtreeSetCachedRowid(BtCursor*, sqlite3_int64);
+SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeGetCachedRowid(BtCursor*);
 
 SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(Btree*, int *aRoot, int nRoot, int, int*);
 SQLITE_PRIVATE struct Pager *sqlite3BtreePager(Btree*);
@@ -7970,53 +8472,62 @@ SQLITE_PRIVATE struct Pager *sqlite3BtreePager(Btree*);
 SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
 SQLITE_PRIVATE void sqlite3BtreeCacheOverflow(BtCursor *);
 SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *);
+SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBt, int iVersion);
+SQLITE_PRIVATE void sqlite3BtreeCursorHints(BtCursor *, unsigned int mask);
+
+#ifndef NDEBUG
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor*);
+#endif
+
+#ifndef SQLITE_OMIT_BTREECOUNT
+SQLITE_PRIVATE int sqlite3BtreeCount(BtCursor *, i64 *);
+#endif
 
 #ifdef SQLITE_TEST
 SQLITE_PRIVATE int sqlite3BtreeCursorInfo(BtCursor*, int*, int);
 SQLITE_PRIVATE void sqlite3BtreeCursorList(Btree*);
 #endif
 
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3BtreeCheckpoint(Btree*, int, int *, int *);
+#endif
+
 /*
 ** If we are not using shared cache, then there is no need to
 ** use mutexes to access the BtShared structures.  So make the
 ** Enter and Leave procedures no-ops.
 */
-#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+#ifndef SQLITE_OMIT_SHARED_CACHE
 SQLITE_PRIVATE   void sqlite3BtreeEnter(Btree*);
-SQLITE_PRIVATE   void sqlite3BtreeLeave(Btree*);
-#ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
-SQLITE_PRIVATE   int sqlite3BtreeHoldsMutex(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeEnterAll(sqlite3*);
+#else
+# define sqlite3BtreeEnter(X) 
+# define sqlite3BtreeEnterAll(X)
 #endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+SQLITE_PRIVATE   int sqlite3BtreeSharable(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeLeave(Btree*);
 SQLITE_PRIVATE   void sqlite3BtreeEnterCursor(BtCursor*);
 SQLITE_PRIVATE   void sqlite3BtreeLeaveCursor(BtCursor*);
-SQLITE_PRIVATE   void sqlite3BtreeEnterAll(sqlite3*);
 SQLITE_PRIVATE   void sqlite3BtreeLeaveAll(sqlite3*);
 #ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
+  /* These routines are used inside assert() statements only. */
+SQLITE_PRIVATE   int sqlite3BtreeHoldsMutex(Btree*);
 SQLITE_PRIVATE   int sqlite3BtreeHoldsAllMutexes(sqlite3*);
+SQLITE_PRIVATE   int sqlite3SchemaMutexHeld(sqlite3*,int,Schema*);
 #endif
-SQLITE_PRIVATE   void sqlite3BtreeMutexArrayEnter(BtreeMutexArray*);
-SQLITE_PRIVATE   void sqlite3BtreeMutexArrayLeave(BtreeMutexArray*);
-SQLITE_PRIVATE   void sqlite3BtreeMutexArrayInsert(BtreeMutexArray*, Btree*);
 #else
-# define sqlite3BtreeEnter(X)
+
+# define sqlite3BtreeSharable(X) 0
 # define sqlite3BtreeLeave(X)
-#ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
-# define sqlite3BtreeHoldsMutex(X) 1
-#endif
 # define sqlite3BtreeEnterCursor(X)
 # define sqlite3BtreeLeaveCursor(X)
-# define sqlite3BtreeEnterAll(X)
 # define sqlite3BtreeLeaveAll(X)
-#ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
+
+# define sqlite3BtreeHoldsMutex(X) 1
 # define sqlite3BtreeHoldsAllMutexes(X) 1
-#endif
-# define sqlite3BtreeMutexArrayEnter(X)
-# define sqlite3BtreeMutexArrayLeave(X)
-# define sqlite3BtreeMutexArrayInsert(X,Y)
+# define sqlite3SchemaMutexHeld(X,Y,Z) 1
 #endif
 
 
@@ -8042,11 +8553,10 @@ SQLITE_PRIVATE   void sqlite3BtreeMutexArrayInsert(BtreeMutexArray*, Btree*);
 ** This header defines the interface to the virtual database engine
 ** or VDBE.  The VDBE implements an abstract machine that runs a
 ** simple program to access and modify the underlying database.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _SQLITE_VDBE_H_
 #define _SQLITE_VDBE_H_
+/* #include <stdio.h> */
 
 /*
 ** A single VDBE is an opaque structure named "Vdbe".  Only routines
@@ -8061,6 +8571,7 @@ typedef struct Vdbe Vdbe;
 */
 typedef struct VdbeFunc VdbeFunc;
 typedef struct Mem Mem;
+typedef struct SubProgram SubProgram;
 
 /*
 ** A single instruction of the virtual machine has an opcode
@@ -8070,12 +8581,12 @@ typedef struct Mem Mem;
 struct VdbeOp {
   u8 opcode;          /* What operation to perform */
   signed char p4type; /* One of the P4_xxx constants for p4 */
-  u8 opflags;         /* Not currently used */
+  u8 opflags;         /* Mask of the OPFLG_* flags in opcodes.h */
   u8 p5;              /* Fifth parameter is an unsigned character */
   int p1;             /* First operand */
   int p2;             /* Second parameter (often the jump destination) */
   int p3;             /* The third parameter */
-  union {             /* forth parameter */
+  union {             /* fourth parameter */
     int i;                 /* Integer value if p4type==P4_INT32 */
     void *p;               /* Generic pointer */
     char *z;               /* Pointer to data for string (char array) types */
@@ -8085,9 +8596,11 @@ struct VdbeOp {
     VdbeFunc *pVdbeFunc;   /* Used when p4type is P4_VDBEFUNC */
     CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
     Mem *pMem;             /* Used when p4type is P4_MEM */
-    sqlite3_vtab *pVtab;   /* Used when p4type is P4_VTAB */
+    VTable *pVtab;         /* Used when p4type is P4_VTAB */
     KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
     int *ai;               /* Used when p4type is P4_INTARRAY */
+    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
+    int (*xAdvance)(BtCursor *, int *);
   } p4;
 #ifdef SQLITE_DEBUG
   char *zComment;          /* Comment to improve readability */
@@ -8099,6 +8612,20 @@ struct VdbeOp {
 };
 typedef struct VdbeOp VdbeOp;
 
+
+/*
+** A sub-routine used to implement a trigger program.
+*/
+struct SubProgram {
+  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
+  int nOp;                      /* Elements in aOp[] */
+  int nMem;                     /* Number of memory cells required */
+  int nCsr;                     /* Number of cursors required */
+  int nOnce;                    /* Number of OP_Once instructions */
+  void *token;                  /* id that may be used to recursive triggers */
+  SubProgram *pNext;            /* Next sub-program already visited */
+};
+
 /*
 ** A smaller version of VdbeOp used for the VdbeAddOpList() function because
 ** it takes up less space.
@@ -8112,7 +8639,7 @@ struct VdbeOpList {
 typedef struct VdbeOpList VdbeOpList;
 
 /*
-** Allowed values of VdbeOp.p3type
+** Allowed values of VdbeOp.p4type
 */
 #define P4_NOTUSED    0   /* The P4 parameter is not used */
 #define P4_DYNAMIC  (-1)  /* Pointer to a string obtained from sqliteMalloc() */
@@ -8122,13 +8649,15 @@ typedef struct VdbeOpList VdbeOpList;
 #define P4_KEYINFO  (-6)  /* P4 is a pointer to a KeyInfo structure */
 #define P4_VDBEFUNC (-7)  /* P4 is a pointer to a VdbeFunc structure */
 #define P4_MEM      (-8)  /* P4 is a pointer to a Mem*    structure */
-#define P4_TRANSIENT (-9) /* P4 is a pointer to a transient string */
+#define P4_TRANSIENT  0   /* P4 is a pointer to a transient string */
 #define P4_VTAB     (-10) /* P4 is a pointer to an sqlite3_vtab structure */
 #define P4_MPRINTF  (-11) /* P4 is a string obtained from sqlite3_mprintf() */
 #define P4_REAL     (-12) /* P4 is a 64-bit floating point value */
 #define P4_INT64    (-13) /* P4 is a 64-bit signed integer */
 #define P4_INT32    (-14) /* P4 is a 32-bit signed integer */
 #define P4_INTARRAY (-15) /* P4 is a vector of 32-bit integers */
+#define P4_SUBPROGRAM  (-18) /* P4 is a pointer to a SubProgram structure */
+#define P4_ADVANCE  (-19) /* P4 is a pointer to BtreeNext() or BtreePrev() */
 
 /* When adding a P4 argument using P4_KEYINFO, a copy of the KeyInfo structure
 ** is made.  That copy is freed when the Vdbe is finalized.  But if the
@@ -8175,153 +8704,156 @@ typedef struct VdbeOpList VdbeOpList;
 /************** Begin file opcodes.h *****************************************/
 /* Automatically generated.  Do not edit */
 /* See the mkopcodeh.awk script for details */
-#define OP_VNext                                1
-#define OP_Affinity                             2
-#define OP_Column                               3
-#define OP_SetCookie                            4
-#define OP_Seek                                 5
-#define OP_Real                               129   /* same as TK_FLOAT    */
-#define OP_Sequence                             6
-#define OP_Savepoint                            7
-#define OP_Ge                                  75   /* same as TK_GE       */
-#define OP_RowKey                               8
-#define OP_SCopy                                9
-#define OP_Eq                                  71   /* same as TK_EQ       */
-#define OP_OpenWrite                           10
-#define OP_NotNull                             69   /* same as TK_NOTNULL  */
-#define OP_If                                  11
-#define OP_ToInt                              144   /* same as TK_TO_INT   */
-#define OP_String8                             91   /* same as TK_STRING   */
-#define OP_VRowid                              12
-#define OP_CollSeq                             13
-#define OP_OpenRead                            14
-#define OP_Expire                              15
-#define OP_AutoCommit                          16
-#define OP_Gt                                  72   /* same as TK_GT       */
-#define OP_Pagecount                           17
-#define OP_IntegrityCk                         18
-#define OP_Sort                                20
-#define OP_Copy                                21
-#define OP_Trace                               22
-#define OP_Function                            23
-#define OP_IfNeg                               24
-#define OP_And                                 64   /* same as TK_AND      */
-#define OP_Subtract                            82   /* same as TK_MINUS    */
-#define OP_Noop                                25
-#define OP_Return                              26
-#define OP_Remainder                           85   /* same as TK_REM      */
-#define OP_NewRowid                            27
-#define OP_Multiply                            83   /* same as TK_STAR     */
-#define OP_Variable                            28
-#define OP_String                              29
-#define OP_RealAffinity                        30
-#define OP_VRename                             31
-#define OP_ParseSchema                         32
-#define OP_VOpen                               33
-#define OP_Close                               34
-#define OP_CreateIndex                         35
-#define OP_IsUnique                            36
-#define OP_NotFound                            37
-#define OP_Int64                               38
-#define OP_MustBeInt                           39
-#define OP_Halt                                40
-#define OP_Rowid                               41
-#define OP_IdxLT                               42
-#define OP_AddImm                              43
-#define OP_Statement                           44
-#define OP_RowData                             45
-#define OP_MemMax                              46
-#define OP_Or                                  63   /* same as TK_OR       */
-#define OP_NotExists                           47
-#define OP_Gosub                               48
-#define OP_Divide                              84   /* same as TK_SLASH    */
-#define OP_Integer                             49
-#define OP_ToNumeric                          143   /* same as TK_TO_NUMERIC*/
-#define OP_Prev                                50
-#define OP_RowSetRead                          51
-#define OP_Concat                              86   /* same as TK_CONCAT   */
-#define OP_RowSetAdd                           52
-#define OP_BitAnd                              77   /* same as TK_BITAND   */
-#define OP_VColumn                             53
-#define OP_CreateTable                         54
-#define OP_Last                                55
-#define OP_SeekLe                              56
-#define OP_IsNull                              68   /* same as TK_ISNULL   */
-#define OP_IncrVacuum                          57
-#define OP_IdxRowid                            58
-#define OP_ShiftRight                          80   /* same as TK_RSHIFT   */
-#define OP_ResetCount                          59
-#define OP_ContextPush                         60
-#define OP_Yield                               61
-#define OP_DropTrigger                         62
-#define OP_DropIndex                           65
-#define OP_IdxGE                               66
-#define OP_IdxDelete                           67
-#define OP_Vacuum                              76
-#define OP_IfNot                               87
-#define OP_DropTable                           88
-#define OP_SeekLt                              89
-#define OP_MakeRecord                          92
-#define OP_ToBlob                             142   /* same as TK_TO_BLOB  */
-#define OP_ResultRow                           93
-#define OP_Delete                              94
-#define OP_AggFinal                            95
-#define OP_Compare                             96
-#define OP_ShiftLeft                           79   /* same as TK_LSHIFT   */
-#define OP_Goto                                97
-#define OP_TableLock                           98
-#define OP_Clear                               99
-#define OP_Le                                  73   /* same as TK_LE       */
-#define OP_VerifyCookie                       100
-#define OP_AggStep                            101
+#define OP_Goto                                 1
+#define OP_Gosub                                2
+#define OP_Return                               3
+#define OP_Yield                                4
+#define OP_HaltIfNull                           5
+#define OP_Halt                                 6
+#define OP_Integer                              7
+#define OP_Int64                                8
+#define OP_Real                               130   /* same as TK_FLOAT    */
+#define OP_String8                             94   /* same as TK_STRING   */
+#define OP_String                               9
+#define OP_Null                                10
+#define OP_Blob                                11
+#define OP_Variable                            12
+#define OP_Move                                13
+#define OP_Copy                                14
+#define OP_SCopy                               15
+#define OP_ResultRow                           16
+#define OP_Concat                              91   /* same as TK_CONCAT   */
+#define OP_Add                                 86   /* same as TK_PLUS     */
+#define OP_Subtract                            87   /* same as TK_MINUS    */
+#define OP_Multiply                            88   /* same as TK_STAR     */
+#define OP_Divide                              89   /* same as TK_SLASH    */
+#define OP_Remainder                           90   /* same as TK_REM      */
+#define OP_CollSeq                             17
+#define OP_Function                            18
+#define OP_BitAnd                              82   /* same as TK_BITAND   */
+#define OP_BitOr                               83   /* same as TK_BITOR    */
+#define OP_ShiftLeft                           84   /* same as TK_LSHIFT   */
+#define OP_ShiftRight                          85   /* same as TK_RSHIFT   */
+#define OP_AddImm                              20
+#define OP_MustBeInt                           21
+#define OP_RealAffinity                        22
 #define OP_ToText                             141   /* same as TK_TO_TEXT  */
-#define OP_Not                                 19   /* same as TK_NOT      */
+#define OP_ToBlob                             142   /* same as TK_TO_BLOB  */
+#define OP_ToNumeric                          143   /* same as TK_TO_NUMERIC*/
+#define OP_ToInt                              144   /* same as TK_TO_INT   */
 #define OP_ToReal                             145   /* same as TK_TO_REAL  */
-#define OP_SetNumColumns                      102
-#define OP_Transaction                        103
-#define OP_VFilter                            104
-#define OP_Ne                                  70   /* same as TK_NE       */
-#define OP_VDestroy                           105
-#define OP_ContextPop                         106
-#define OP_BitOr                               78   /* same as TK_BITOR    */
-#define OP_Next                               107
-#define OP_IdxInsert                          108
-#define OP_Lt                                  74   /* same as TK_LT       */
-#define OP_SeekGe                             109
-#define OP_Insert                             110
-#define OP_Destroy                            111
-#define OP_ReadCookie                         112
-#define OP_LoadAnalysis                       113
-#define OP_Explain                            114
-#define OP_OpenPseudo                         115
-#define OP_OpenEphemeral                      116
-#define OP_Null                               117
-#define OP_Move                               118
-#define OP_Blob                               119
-#define OP_Add                                 81   /* same as TK_PLUS     */
-#define OP_Rewind                             120
-#define OP_SeekGt                             121
-#define OP_VBegin                             122
-#define OP_VUpdate                            123
-#define OP_IfZero                             124
-#define OP_BitNot                              90   /* same as TK_BITNOT   */
-#define OP_VCreate                            125
-#define OP_Found                              126
-#define OP_IfPos                              127
-#define OP_NullRow                            128
-#define OP_Jump                               130
-#define OP_Permutation                        131
-
-/* The following opcode values are never used */
-#define OP_NotUsed_132                        132
-#define OP_NotUsed_133                        133
-#define OP_NotUsed_134                        134
-#define OP_NotUsed_135                        135
-#define OP_NotUsed_136                        136
-#define OP_NotUsed_137                        137
-#define OP_NotUsed_138                        138
-#define OP_NotUsed_139                        139
-#define OP_NotUsed_140                        140
+#define OP_Eq                                  76   /* same as TK_EQ       */
+#define OP_Ne                                  75   /* same as TK_NE       */
+#define OP_Lt                                  79   /* same as TK_LT       */
+#define OP_Le                                  78   /* same as TK_LE       */
+#define OP_Gt                                  77   /* same as TK_GT       */
+#define OP_Ge                                  80   /* same as TK_GE       */
+#define OP_Permutation                         23
+#define OP_Compare                             24
+#define OP_Jump                                25
+#define OP_And                                 69   /* same as TK_AND      */
+#define OP_Or                                  68   /* same as TK_OR       */
+#define OP_Not                                 19   /* same as TK_NOT      */
+#define OP_BitNot                              93   /* same as TK_BITNOT   */
+#define OP_Once                                26
+#define OP_If                                  27
+#define OP_IfNot                               28
+#define OP_IsNull                              73   /* same as TK_ISNULL   */
+#define OP_NotNull                             74   /* same as TK_NOTNULL  */
+#define OP_Column                              29
+#define OP_Affinity                            30
+#define OP_MakeRecord                          31
+#define OP_Count                               32
+#define OP_Savepoint                           33
+#define OP_AutoCommit                          34
+#define OP_Transaction                         35
+#define OP_ReadCookie                          36
+#define OP_SetCookie                           37
+#define OP_VerifyCookie                        38
+#define OP_OpenRead                            39
+#define OP_OpenWrite                           40
+#define OP_OpenAutoindex                       41
+#define OP_OpenEphemeral                       42
+#define OP_SorterOpen                          43
+#define OP_OpenPseudo                          44
+#define OP_Close                               45
+#define OP_SeekLt                              46
+#define OP_SeekLe                              47
+#define OP_SeekGe                              48
+#define OP_SeekGt                              49
+#define OP_Seek                                50
+#define OP_NotFound                            51
+#define OP_Found                               52
+#define OP_IsUnique                            53
+#define OP_NotExists                           54
+#define OP_Sequence                            55
+#define OP_NewRowid                            56
+#define OP_Insert                              57
+#define OP_InsertInt                           58
+#define OP_Delete                              59
+#define OP_ResetCount                          60
+#define OP_SorterCompare                       61
+#define OP_SorterData                          62
+#define OP_RowKey                              63
+#define OP_RowData                             64
+#define OP_Rowid                               65
+#define OP_NullRow                             66
+#define OP_Last                                67
+#define OP_SorterSort                          70
+#define OP_Sort                                71
+#define OP_Rewind                              72
+#define OP_SorterNext                          81
+#define OP_Prev                                92
+#define OP_Next                                95
+#define OP_SorterInsert                        96
+#define OP_IdxInsert                           97
+#define OP_IdxDelete                           98
+#define OP_IdxRowid                            99
+#define OP_IdxLT                              100
+#define OP_IdxGE                              101
+#define OP_Destroy                            102
+#define OP_Clear                              103
+#define OP_CreateIndex                        104
+#define OP_CreateTable                        105
+#define OP_ParseSchema                        106
+#define OP_LoadAnalysis                       107
+#define OP_DropTable                          108
+#define OP_DropIndex                          109
+#define OP_DropTrigger                        110
+#define OP_IntegrityCk                        111
+#define OP_RowSetAdd                          112
+#define OP_RowSetRead                         113
+#define OP_RowSetTest                         114
+#define OP_Program                            115
+#define OP_Param                              116
+#define OP_FkCounter                          117
+#define OP_FkIfZero                           118
+#define OP_MemMax                             119
+#define OP_IfPos                              120
+#define OP_IfNeg                              121
+#define OP_IfZero                             122
+#define OP_AggStep                            123
+#define OP_AggFinal                           124
+#define OP_Checkpoint                         125
+#define OP_JournalMode                        126
+#define OP_Vacuum                             127
+#define OP_IncrVacuum                         128
+#define OP_Expire                             129
+#define OP_TableLock                          131
+#define OP_VBegin                             132
+#define OP_VCreate                            133
+#define OP_VDestroy                           134
+#define OP_VOpen                              135
+#define OP_VFilter                            136
+#define OP_VColumn                            137
+#define OP_VNext                              138
+#define OP_VRename                            139
+#define OP_VUpdate                            140
+#define OP_Pagecount                          146
+#define OP_MaxPgcnt                           147
+#define OP_Trace                              148
+#define OP_Noop                               149
+#define OP_Explain                            150
 
 
 /* Properties such as "out2" or "jump" that are specified in
@@ -8333,27 +8865,28 @@ typedef struct VdbeOpList VdbeOpList;
 #define OPFLG_IN1             0x0004  /* in1:   P1 is an input */
 #define OPFLG_IN2             0x0008  /* in2:   P2 is an input */
 #define OPFLG_IN3             0x0010  /* in3:   P3 is an input */
-#define OPFLG_OUT3            0x0020  /* out3:  P3 is an output */
+#define OPFLG_OUT2            0x0020  /* out2:  P2 is an output */
+#define OPFLG_OUT3            0x0040  /* out3:  P3 is an output */
 #define OPFLG_INITIALIZER {\
-/*   0 */ 0x00, 0x01, 0x00, 0x00, 0x10, 0x08, 0x02, 0x00,\
-/*   8 */ 0x00, 0x04, 0x00, 0x05, 0x02, 0x00, 0x00, 0x00,\
-/*  16 */ 0x00, 0x02, 0x00, 0x04, 0x01, 0x04, 0x00, 0x00,\
-/*  24 */ 0x05, 0x00, 0x04, 0x02, 0x02, 0x02, 0x04, 0x00,\
-/*  32 */ 0x00, 0x00, 0x00, 0x02, 0x11, 0x11, 0x02, 0x05,\
-/*  40 */ 0x00, 0x02, 0x11, 0x04, 0x00, 0x00, 0x0c, 0x11,\
-/*  48 */ 0x01, 0x02, 0x01, 0x21, 0x08, 0x00, 0x02, 0x01,\
-/*  56 */ 0x11, 0x01, 0x02, 0x00, 0x00, 0x04, 0x00, 0x2c,\
-/*  64 */ 0x2c, 0x00, 0x11, 0x00, 0x05, 0x05, 0x15, 0x15,\
-/*  72 */ 0x15, 0x15, 0x15, 0x15, 0x00, 0x2c, 0x2c, 0x2c,\
-/*  80 */ 0x2c, 0x2c, 0x2c, 0x2c, 0x2c, 0x2c, 0x2c, 0x05,\
-/*  88 */ 0x00, 0x11, 0x04, 0x02, 0x00, 0x00, 0x00, 0x00,\
-/*  96 */ 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
-/* 104 */ 0x01, 0x00, 0x00, 0x01, 0x08, 0x11, 0x00, 0x02,\
-/* 112 */ 0x02, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x02,\
-/* 120 */ 0x01, 0x11, 0x00, 0x00, 0x05, 0x00, 0x11, 0x05,\
-/* 128 */ 0x00, 0x02, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,\
-/* 136 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x04, 0x04,\
-/* 144 */ 0x04, 0x04,}
+/*   0 */ 0x00, 0x01, 0x01, 0x04, 0x04, 0x10, 0x00, 0x02,\
+/*   8 */ 0x02, 0x02, 0x02, 0x02, 0x02, 0x00, 0x24, 0x24,\
+/*  16 */ 0x00, 0x00, 0x00, 0x24, 0x04, 0x05, 0x04, 0x00,\
+/*  24 */ 0x00, 0x01, 0x01, 0x05, 0x05, 0x00, 0x00, 0x00,\
+/*  32 */ 0x02, 0x00, 0x00, 0x00, 0x02, 0x10, 0x00, 0x00,\
+/*  40 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11,\
+/*  48 */ 0x11, 0x11, 0x08, 0x11, 0x11, 0x11, 0x11, 0x02,\
+/*  56 */ 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
+/*  64 */ 0x00, 0x02, 0x00, 0x01, 0x4c, 0x4c, 0x01, 0x01,\
+/*  72 */ 0x01, 0x05, 0x05, 0x15, 0x15, 0x15, 0x15, 0x15,\
+/*  80 */ 0x15, 0x01, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c,\
+/*  88 */ 0x4c, 0x4c, 0x4c, 0x4c, 0x01, 0x24, 0x02, 0x01,\
+/*  96 */ 0x08, 0x08, 0x00, 0x02, 0x01, 0x01, 0x02, 0x00,\
+/* 104 */ 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
+/* 112 */ 0x0c, 0x45, 0x15, 0x01, 0x02, 0x00, 0x01, 0x08,\
+/* 120 */ 0x05, 0x05, 0x05, 0x00, 0x00, 0x00, 0x02, 0x00,\
+/* 128 */ 0x01, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00,\
+/* 136 */ 0x01, 0x00, 0x01, 0x00, 0x00, 0x04, 0x04, 0x04,\
+/* 144 */ 0x04, 0x04, 0x02, 0x02, 0x00, 0x00, 0x00,}
 
 /************** End of opcodes.h *********************************************/
 /************** Continuing where we left off in vdbe.h ***********************/
@@ -8368,41 +8901,53 @@ SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe*,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(Vdbe*,int,int,int,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
-SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
-SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
-SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe*, int addr, int P3);
+SQLITE_PRIVATE void sqlite3VdbeAddParseSchemaOp(Vdbe*,int,char*);
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe*, u32 addr, int P1);
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe*, u32 addr, int P2);
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe*, u32 addr, int P3);
 SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe*, u8 P5);
 SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe*, int addr);
-SQLITE_PRIVATE void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
+SQLITE_PRIVATE void sqlite3VdbeChangeToNoop(Vdbe*, int addr);
 SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
 SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe*, int);
 SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
 SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe*);
 SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe*);
-SQLITE_PRIVATE void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int);
+SQLITE_PRIVATE void sqlite3VdbeDeleteObject(sqlite3*,Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(Vdbe*,Parse*);
 SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe*);
 SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe*, int);
 SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe*);
 #ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3VdbeAssertMayAbort(Vdbe *, int);
 SQLITE_PRIVATE   void sqlite3VdbeTrace(Vdbe*,FILE*);
 #endif
 SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeRewind(Vdbe*);
 SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe*);
 SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe*,int);
 SQLITE_PRIVATE int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, void(*)(void*));
 SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe*);
 SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe*);
-SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe*, const char *z, int n);
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe*, const char *z, int n, int);
 SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe*,Vdbe*);
-
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
-SQLITE_PRIVATE int sqlite3VdbeReleaseMemory(int);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeTakeOpArray(Vdbe*, int*, int*);
+SQLITE_PRIVATE sqlite3_value *sqlite3VdbeGetValue(Vdbe*, int, u8);
+SQLITE_PRIVATE void sqlite3VdbeSetVarmask(Vdbe*, int);
+#ifndef SQLITE_OMIT_TRACE
+SQLITE_PRIVATE   char *sqlite3VdbeExpandSql(Vdbe*, const char*);
 #endif
-SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,
-                                        UnpackedRecord*,int);
-SQLITE_PRIVATE void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord*);
+
+SQLITE_PRIVATE void sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,UnpackedRecord*);
 SQLITE_PRIVATE int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(KeyInfo *, char *, int, char **);
+
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE void sqlite3VdbeLinkSubProgram(Vdbe *, SubProgram *);
+#endif
 
 
 #ifndef NDEBUG
@@ -8435,16 +8980,15 @@ SQLITE_PRIVATE   void sqlite3VdbeNoopComment(Vdbe*, const char*, ...);
 ** This header file defines the interface that the sqlite page cache
 ** subsystem.  The page cache subsystem reads and writes a file a page
 ** at a time and provides a journal for rollback.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 #ifndef _PAGER_H_
 #define _PAGER_H_
 
 /*
-** If defined as non-zero, auto-vacuum is enabled by default. Otherwise
-** it must be turned on for each database using "PRAGMA auto_vacuum = 1".
+** Default maximum size for persistent journal files. A negative 
+** value means no limit. This value may be overridden using the 
+** sqlite3PagerJournalSizeLimit() API. See also "PRAGMA journal_size_limit".
 */
 #ifndef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT
   #define SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT -1
@@ -8466,13 +9010,23 @@ typedef struct Pager Pager;
 */
 typedef struct PgHdr DbPage;
 
+/*
+** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is
+** reserved for working around a windows/posix incompatibility). It is
+** used in the journal to signify that the remainder of the journal file 
+** is devoted to storing a master journal name - there are no more pages to
+** roll back. See comments for function writeMasterJournal() in pager.c 
+** for details.
+*/
+#define PAGER_MJ_PGNO(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1))
+
 /*
 ** Allowed values for the flags parameter to sqlite3PagerOpen().
 **
-** NOTE: This values must match the corresponding BTREE_ values in btree.h.
+** NOTE: These values must match the corresponding BTREE_ values in btree.h.
 */
 #define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */
-#define PAGER_NO_READLOCK   0x0002    /* Omit readlocks on readonly files */
+#define PAGER_MEMORY        0x0002    /* In-memory database */
 
 /*
 ** Valid values for the second argument to sqlite3PagerLockingMode().
@@ -8482,85 +9036,116 @@ typedef struct PgHdr DbPage;
 #define PAGER_LOCKINGMODE_EXCLUSIVE   1
 
 /*
-** Valid values for the second argument to sqlite3PagerJournalMode().
+** Numeric constants that encode the journalmode.  
 */
-#define PAGER_JOURNALMODE_QUERY      -1
+#define PAGER_JOURNALMODE_QUERY     (-1)  /* Query the value of journalmode */
 #define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
 #define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
 #define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
 #define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
 #define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
+#define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
 
 /*
-** See source code comments for a detailed description of the following
-** routines:
+** The remainder of this file contains the declarations of the functions
+** that make up the Pager sub-system API. See source code comments for 
+** a detailed description of each routine.
 */
-SQLITE_PRIVATE int sqlite3PagerOpen(sqlite3_vfs *, Pager **ppPager, const char*, int,int,int);
-SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
-SQLITE_PRIVATE void sqlite3PagerSetReiniter(Pager*, void(*)(DbPage*));
-SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager*, u16*);
-SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager*, int);
-SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
-SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager*, int);
+
+/* Open and close a Pager connection. */ 
+SQLITE_PRIVATE int sqlite3PagerOpen(
+  sqlite3_vfs*,
+  Pager **ppPager,
+  const char*,
+  int,
+  int,
+  int,
+  void(*)(DbPage*)
+);
 SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager);
+SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
+
+/* Functions used to configure a Pager object. */
+SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager*, u32*, int);
+SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager*, int);
+SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager*, int);
+SQLITE_PRIVATE void sqlite3PagerShrink(Pager*);
+SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(Pager*,int,int,int);
+SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *, int);
+SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *, int);
+SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager*);
+SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager*);
+SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
+SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager*);
+
+/* Functions used to obtain and release page references. */ 
 SQLITE_PRIVATE int sqlite3PagerAcquire(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);
 #define sqlite3PagerGet(A,B,C) sqlite3PagerAcquire(A,B,C,0)
 SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);
-SQLITE_PRIVATE int sqlite3PagerPageRefcount(DbPage*);
-SQLITE_PRIVATE int sqlite3PagerRef(DbPage*);
-SQLITE_PRIVATE int sqlite3PagerUnref(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerRef(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerUnref(DbPage*);
+
+/* Operations on page references. */
 SQLITE_PRIVATE int sqlite3PagerWrite(DbPage*);
-SQLITE_PRIVATE int sqlite3PagerPagecount(Pager*, int*);
-SQLITE_PRIVATE int sqlite3PagerBegin(DbPage*, int exFlag);
-SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(Pager*,const char *zMaster, int);
-SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager*);
-SQLITE_PRIVATE int sqlite3PagerRollback(Pager*);
-SQLITE_PRIVATE u8 sqlite3PagerIsreadonly(Pager*);
-SQLITE_PRIVATE void sqlite3PagerDontRollback(DbPage*);
-SQLITE_PRIVATE int sqlite3PagerDontWrite(DbPage*);
-SQLITE_PRIVATE int sqlite3PagerRefcount(Pager*);
-SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(Pager*,int,int);
-SQLITE_PRIVATE const char *sqlite3PagerFilename(Pager*);
-SQLITE_PRIVATE const sqlite3_vfs *sqlite3PagerVfs(Pager*);
-SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager*);
-SQLITE_PRIVATE const char *sqlite3PagerDirname(Pager*);
-SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager*);
-SQLITE_PRIVATE int sqlite3PagerNosync(Pager*);
+SQLITE_PRIVATE void sqlite3PagerDontWrite(DbPage*);
 SQLITE_PRIVATE int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int);
+SQLITE_PRIVATE int sqlite3PagerPageRefcount(DbPage*);
 SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *); 
 SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *); 
-SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *, int);
-SQLITE_PRIVATE int sqlite3PagerJournalMode(Pager *, int);
-SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
-SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager*);
-SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager);
 
+/* Functions used to manage pager transactions and savepoints. */
+SQLITE_PRIVATE void sqlite3PagerPagecount(Pager*, int*);
+SQLITE_PRIVATE int sqlite3PagerBegin(Pager*, int exFlag, int);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(Pager*,const char *zMaster, int);
+SQLITE_PRIVATE int sqlite3PagerExclusiveLock(Pager*);
+SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager*);
+SQLITE_PRIVATE int sqlite3PagerRollback(Pager*);
 SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
 SQLITE_PRIVATE int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
+SQLITE_PRIVATE int sqlite3PagerSharedLock(Pager *pPager);
 
-#ifndef SQLITE_OMIT_AUTOVACUUM
-SQLITE_PRIVATE   void sqlite3PagerTruncateImage(Pager*,Pgno);
-SQLITE_PRIVATE   Pgno sqlite3PagerImageSize(Pager *);
+SQLITE_PRIVATE int sqlite3PagerCheckpoint(Pager *pPager, int, int*, int*);
+SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager);
+SQLITE_PRIVATE int sqlite3PagerWalCallback(Pager *pPager);
+SQLITE_PRIVATE int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
+SQLITE_PRIVATE int sqlite3PagerCloseWal(Pager *pPager);
+#ifdef SQLITE_ENABLE_ZIPVFS
+SQLITE_PRIVATE   int sqlite3PagerWalFramesize(Pager *pPager);
 #endif
 
-#ifdef SQLITE_HAS_CODEC
-SQLITE_PRIVATE   void sqlite3PagerSetCodec(Pager*,void*(*)(void*,void*,Pgno,int),void*);
+/* Functions used to query pager state and configuration. */
+SQLITE_PRIVATE u8 sqlite3PagerIsreadonly(Pager*);
+SQLITE_PRIVATE int sqlite3PagerRefcount(Pager*);
+SQLITE_PRIVATE int sqlite3PagerMemUsed(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerFilename(Pager*, int);
+SQLITE_PRIVATE const sqlite3_vfs *sqlite3PagerVfs(Pager*);
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager*);
+SQLITE_PRIVATE int sqlite3PagerNosync(Pager*);
+SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager*);
+SQLITE_PRIVATE int sqlite3PagerIsMemdb(Pager*);
+SQLITE_PRIVATE void sqlite3PagerCacheStat(Pager *, int, int, int *);
+SQLITE_PRIVATE void sqlite3PagerClearCache(Pager *);
+
+/* Functions used to truncate the database file. */
+SQLITE_PRIVATE void sqlite3PagerTruncateImage(Pager*,Pgno);
+
+#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_WAL)
+SQLITE_PRIVATE void *sqlite3PagerCodec(DbPage *);
 #endif
 
+/* Functions to support testing and debugging. */
 #if !defined(NDEBUG) || defined(SQLITE_TEST)
 SQLITE_PRIVATE   Pgno sqlite3PagerPagenumber(DbPage*);
 SQLITE_PRIVATE   int sqlite3PagerIswriteable(DbPage*);
 #endif
-
 #ifdef SQLITE_TEST
 SQLITE_PRIVATE   int *sqlite3PagerStats(Pager*);
 SQLITE_PRIVATE   void sqlite3PagerRefdump(Pager*);
-SQLITE_PRIVATE   int sqlite3PagerIsMemdb(Pager*);
-#endif
-
-#ifdef SQLITE_TEST
-void disable_simulated_io_errors(void);
-void enable_simulated_io_errors(void);
+  void disable_simulated_io_errors(void);
+  void enable_simulated_io_errors(void);
 #else
 # define disable_simulated_io_errors()
 # define enable_simulated_io_errors()
@@ -8585,8 +9170,6 @@ void enable_simulated_io_errors(void);
 *************************************************************************
 ** This header file defines the interface that the sqlite page cache
 ** subsystem. 
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 #ifndef _PCACHE_H_
@@ -8599,11 +9182,12 @@ typedef struct PCache PCache;
 ** structure.
 */
 struct PgHdr {
-  void *pData;                   /* Content of this page */
+  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
+  void *pData;                   /* Page data */
   void *pExtra;                  /* Extra content */
   PgHdr *pDirty;                 /* Transient list of dirty pages */
-  Pgno pgno;                     /* Page number for this page */
   Pager *pPager;                 /* The pager this page is part of */
+  Pgno pgno;                     /* Page number for this page */
 #ifdef SQLITE_CHECK_PAGES
   u32 pageHash;                  /* Hash of page content */
 #endif
@@ -8685,7 +9269,7 @@ SQLITE_PRIVATE void sqlite3PcacheClose(PCache*);
 SQLITE_PRIVATE void sqlite3PcacheClearSyncFlags(PCache *);
 
 /* Discard the contents of the cache */
-SQLITE_PRIVATE int sqlite3PcacheClear(PCache*);
+SQLITE_PRIVATE void sqlite3PcacheClear(PCache*);
 
 /* Return the total number of outstanding page references */
 SQLITE_PRIVATE int sqlite3PcacheRefCount(PCache*);
@@ -8698,7 +9282,7 @@ SQLITE_PRIVATE int sqlite3PcachePageRefcount(PgHdr*);
 /* Return the total number of pages stored in the cache */
 SQLITE_PRIVATE int sqlite3PcachePagecount(PCache*);
 
-#ifdef SQLITE_CHECK_PAGES
+#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
 /* Iterate through all dirty pages currently stored in the cache. This
 ** interface is only available if SQLITE_CHECK_PAGES is defined when the 
 ** library is built.
@@ -8717,6 +9301,9 @@ SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *, int);
 SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *);
 #endif
 
+/* Free up as much memory as possible from the page cache */
+SQLITE_PRIVATE void sqlite3PcacheShrink(PCache*);
+
 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
 /* Try to return memory used by the pcache module to the main memory heap */
 SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int);
@@ -8753,8 +9340,6 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 **
 ** This header file is #include-ed by sqliteInt.h and thus ends up
 ** being included by every source file.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _SQLITE_OS_H_
 #define _SQLITE_OS_H_
@@ -8762,7 +9347,7 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 /*
 ** Figure out if we are dealing with Unix, Windows, or some other
 ** operating system.  After the following block of preprocess macros,
-** all of SQLITE_OS_UNIX, SQLITE_OS_WIN, SQLITE_OS_OS2, and SQLITE_OS_OTHER 
+** all of SQLITE_OS_UNIX, SQLITE_OS_WIN, and SQLITE_OS_OTHER 
 ** will defined to either 1 or 0.  One of the four will be 1.  The other 
 ** three will be 0.
 */
@@ -8772,8 +9357,6 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 #   define SQLITE_OS_UNIX 0
 #   undef SQLITE_OS_WIN
 #   define SQLITE_OS_WIN 0
-#   undef SQLITE_OS_OS2
-#   define SQLITE_OS_OS2 0
 # else
 #   undef SQLITE_OS_OTHER
 # endif
@@ -8784,19 +9367,12 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 #   if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)
 #     define SQLITE_OS_WIN 1
 #     define SQLITE_OS_UNIX 0
-#     define SQLITE_OS_OS2 0
-#   elif defined(__EMX__) || defined(_OS2) || defined(OS2) || defined(_OS2_) || defined(__OS2__)
-#     define SQLITE_OS_WIN 0
-#     define SQLITE_OS_UNIX 0
-#     define SQLITE_OS_OS2 1
 #   else
 #     define SQLITE_OS_WIN 0
 #     define SQLITE_OS_UNIX 1
-#     define SQLITE_OS_OS2 0
 #  endif
 # else
 #  define SQLITE_OS_UNIX 0
-#  define SQLITE_OS_OS2 0
 # endif
 #else
 # ifndef SQLITE_OS_WIN
@@ -8804,6 +9380,31 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 # endif
 #endif
 
+#if SQLITE_OS_WIN
+# include <windows.h>
+#endif
+
+/*
+** Determine if we are dealing with Windows NT.
+**
+** We ought to be able to determine if we are compiling for win98 or winNT
+** using the _WIN32_WINNT macro as follows:
+**
+** #if defined(_WIN32_WINNT)
+** # define SQLITE_OS_WINNT 1
+** #else
+** # define SQLITE_OS_WINNT 0
+** #endif
+**
+** However, vs2005 does not set _WIN32_WINNT by default, as it ought to,
+** so the above test does not work.  We'll just assume that everything is
+** winNT unless the programmer explicitly says otherwise by setting
+** SQLITE_OS_WINNT to 0.
+*/
+#if SQLITE_OS_WIN && !defined(SQLITE_OS_WINNT)
+# define SQLITE_OS_WINNT 1
+#endif
+
 /*
 ** Determine if we are dealing with WindowsCE - which has a much
 ** reduced API.
@@ -8814,29 +9415,20 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 # define SQLITE_OS_WINCE 0
 #endif
 
+/*
+** Determine if we are dealing with WinRT, which provides only a subset of
+** the full Win32 API.
+*/
+#if !defined(SQLITE_OS_WINRT)
+# define SQLITE_OS_WINRT 0
+#endif
 
 /*
-** Define the maximum size of a temporary filename
-*/
-#if SQLITE_OS_WIN
-# include <windows.h>
-# define SQLITE_TEMPNAME_SIZE (MAX_PATH+50)
-#elif SQLITE_OS_OS2
-# if (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3) && defined(OS2_HIGH_MEMORY)
-#  include <os2safe.h> /* has to be included before os2.h for linking to work */
-# endif
-# define INCL_DOSDATETIME
-# define INCL_DOSFILEMGR
-# define INCL_DOSERRORS
-# define INCL_DOSMISC
-# define INCL_DOSPROCESS
-# define INCL_DOSMODULEMGR
-# define INCL_DOSSEMAPHORES
-# include <os2.h>
-# include <uconv.h>
-# define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP)
-#else
-# define SQLITE_TEMPNAME_SIZE 200
+** When compiled for WinCE or WinRT, there is no concept of the current
+** directory.
+ */
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+# define SQLITE_CURDIR 1
 #endif
 
 /* If the SET_FULLSYNC macro is not defined above, then make it
@@ -8850,7 +9442,7 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 ** The default size of a disk sector
 */
 #ifndef SQLITE_DEFAULT_SECTOR_SIZE
-# define SQLITE_DEFAULT_SECTOR_SIZE 512
+# define SQLITE_DEFAULT_SECTOR_SIZE 4096
 #endif
 
 /*
@@ -8932,9 +9524,7 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 ** a random byte is selected for a shared lock.  The pool of bytes for
 ** shared locks begins at SHARED_FIRST. 
 **
-** These #defines are available in sqlite_aux.h so that adaptors for
-** connecting SQLite to other operating systems can use the same byte
-** ranges for locking.  In particular, the same locking strategy and
+** The same locking strategy and
 ** byte ranges are used for Unix.  This leaves open the possiblity of having
 ** clients on win95, winNT, and unix all talking to the same shared file
 ** and all locking correctly.  To do so would require that samba (or whatever
@@ -8958,17 +9548,20 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
 ** 1GB boundary.
 **
 */
-#ifndef SQLITE_TEST
-#define PENDING_BYTE      0x40000000  /* First byte past the 1GB boundary */
+#ifdef SQLITE_OMIT_WSD
+# define PENDING_BYTE     (0x40000000)
 #else
-SQLITE_API extern unsigned int sqlite3_pending_byte;
-#define PENDING_BYTE sqlite3_pending_byte
+# define PENDING_BYTE      sqlite3PendingByte
 #endif
-
 #define RESERVED_BYTE     (PENDING_BYTE+1)
 #define SHARED_FIRST      (PENDING_BYTE+2)
 #define SHARED_SIZE       510
 
+/*
+** Wrapper around OS specific sqlite3_os_init() function.
+*/
+SQLITE_PRIVATE int sqlite3OsInit(void);
+
 /* 
 ** Functions for accessing sqlite3_file methods 
 */
@@ -8982,9 +9575,15 @@ SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file*, int);
 SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file*, int);
 SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
 SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file*,int,void*);
+SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file*,int,void*);
 #define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
 SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id);
 SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsShmMap(sqlite3_file *,int,int,int,void volatile **);
+SQLITE_PRIVATE int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
+SQLITE_PRIVATE void sqlite3OsShmBarrier(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsShmUnmap(sqlite3_file *id, int);
+
 
 /* 
 ** Functions for accessing sqlite3_vfs methods 
@@ -8996,12 +9595,12 @@ SQLITE_PRIVATE int sqlite3OsFullPathname(sqlite3_vfs *, const char *, int, char
 #ifndef SQLITE_OMIT_LOAD_EXTENSION
 SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *, const char *);
 SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *, int, char *);
-void (*sqlite3OsDlSym(sqlite3_vfs *, void *, const char *))(void);
+SQLITE_PRIVATE void (*sqlite3OsDlSym(sqlite3_vfs *, void *, const char *))(void);
 SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *, void *);
 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
 SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *, int, char *);
 SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *, int);
-SQLITE_PRIVATE int sqlite3OsCurrentTime(sqlite3_vfs *, double*);
+SQLITE_PRIVATE int sqlite3OsCurrentTimeInt64(sqlite3_vfs *, sqlite3_int64*);
 
 /*
 ** Convenience functions for opening and closing files using 
@@ -9036,8 +9635,6 @@ SQLITE_PRIVATE int sqlite3OsCloseFree(sqlite3_file *);
 ** NOTE:  source files should *not* #include this header file directly.
 ** Source files should #include the sqliteInt.h file and let that file
 ** include this one indirectly.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
@@ -9056,8 +9653,6 @@ SQLITE_PRIVATE int sqlite3OsCloseFree(sqlite3_file *);
 **   SQLITE_MUTEX_PTHREADS     For multi-threaded applications on Unix.
 **
 **   SQLITE_MUTEX_W32          For multi-threaded applications on Win32.
-**
-**   SQLITE_MUTEX_OS2          For multi-threaded applications on OS/2.
 */
 #if !SQLITE_THREADSAFE
 # define SQLITE_MUTEX_OMIT
@@ -9067,8 +9662,6 @@ SQLITE_PRIVATE int sqlite3OsCloseFree(sqlite3_file *);
 #    define SQLITE_MUTEX_PTHREADS
 #  elif SQLITE_OS_WIN
 #    define SQLITE_MUTEX_W32
-#  elif SQLITE_OS_OS2
-#    define SQLITE_MUTEX_OS2
 #  else
 #    define SQLITE_MUTEX_NOOP
 #  endif
@@ -9080,15 +9673,18 @@ SQLITE_PRIVATE int sqlite3OsCloseFree(sqlite3_file *);
 */
 #define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
 #define sqlite3_mutex_free(X)
-#define sqlite3_mutex_enter(X)
+#define sqlite3_mutex_enter(X)    
 #define sqlite3_mutex_try(X)      SQLITE_OK
-#define sqlite3_mutex_leave(X)
-#define sqlite3_mutex_held(X)     1
-#define sqlite3_mutex_notheld(X)  1
+#define sqlite3_mutex_leave(X)    
+#define sqlite3_mutex_held(X)     ((void)(X),1)
+#define sqlite3_mutex_notheld(X)  ((void)(X),1)
 #define sqlite3MutexAlloc(X)      ((sqlite3_mutex*)8)
 #define sqlite3MutexInit()        SQLITE_OK
 #define sqlite3MutexEnd()
-#endif /* defined(SQLITE_OMIT_MUTEX) */
+#define MUTEX_LOGIC(X)
+#else
+#define MUTEX_LOGIC(X)            X
+#endif /* defined(SQLITE_MUTEX_OMIT) */
 
 /************** End of mutex.h ***********************************************/
 /************** Continuing where we left off in sqliteInt.h ******************/
@@ -9106,41 +9702,43 @@ struct Db {
   Btree *pBt;          /* The B*Tree structure for this database file */
   u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
   u8 safety_level;     /* How aggressive at syncing data to disk */
-  void *pAux;               /* Auxiliary data.  Usually NULL */
-  void (*xFreeAux)(void*);  /* Routine to free pAux */
   Schema *pSchema;     /* Pointer to database schema (possibly shared) */
 };
 
 /*
 ** An instance of the following structure stores a database schema.
 **
-** If there are no virtual tables configured in this schema, the
-** Schema.db variable is set to NULL. After the first virtual table
-** has been added, it is set to point to the database connection 
-** used to create the connection. Once a virtual table has been
-** added to the Schema structure and the Schema.db variable populated, 
-** only that database connection may use the Schema to prepare 
-** statements.
+** Most Schema objects are associated with a Btree.  The exception is
+** the Schema for the TEMP databaes (sqlite3.aDb[1]) which is free-standing.
+** In shared cache mode, a single Schema object can be shared by multiple
+** Btrees that refer to the same underlying BtShared object.
+** 
+** Schema objects are automatically deallocated when the last Btree that
+** references them is destroyed.   The TEMP Schema is manually freed by
+** sqlite3_close().
+*
+** A thread must be holding a mutex on the corresponding Btree in order
+** to access Schema content.  This implies that the thread must also be
+** holding a mutex on the sqlite3 connection pointer that owns the Btree.
+** For a TEMP Schema, only the connection mutex is required.
 */
 struct Schema {
   int schema_cookie;   /* Database schema version number for this file */
+  int iGeneration;     /* Generation counter.  Incremented with each change */
   Hash tblHash;        /* All tables indexed by name */
   Hash idxHash;        /* All (named) indices indexed by name */
   Hash trigHash;       /* All triggers indexed by name */
-  Hash aFKey;          /* Foreign keys indexed by to-table */
+  Hash fkeyHash;       /* All foreign keys by referenced table name */
   Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
   u8 file_format;      /* Schema format version for this file */
   u8 enc;              /* Text encoding used by this database */
   u16 flags;           /* Flags associated with this schema */
   int cache_size;      /* Number of pages to use in the cache */
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-  sqlite3 *db;         /* "Owner" connection. See comment above */
-#endif
 };
 
 /*
 ** These macros can be used to test, set, or clear bits in the 
-** Db.flags field.
+** Db.pSchema->flags field.
 */
 #define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->flags&(P))==(P))
 #define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->flags&(P))!=0)
@@ -9148,7 +9746,7 @@ struct Schema {
 #define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->flags&=~(P)
 
 /*
-** Allowed values for the DB.flags field.
+** Allowed values for the DB.pSchema->flags field.
 **
 ** The DB_SchemaLoaded flag is set after the database schema has been
 ** read into internal hash tables.
@@ -9165,7 +9763,7 @@ struct Schema {
 ** The number of different kinds of things that can be limited
 ** using the sqlite3_limit() interface.
 */
-#define SQLITE_N_LIMIT (SQLITE_LIMIT_VARIABLE_NUMBER+1)
+#define SQLITE_N_LIMIT (SQLITE_LIMIT_TRIGGER_DEPTH+1)
 
 /*
 ** Lookaside malloc is a set of fixed-size buffers that can be used
@@ -9179,13 +9777,21 @@ struct Schema {
 ** lookaside malloc subsystem.  Each available memory allocation in
 ** the lookaside subsystem is stored on a linked list of LookasideSlot
 ** objects.
+**
+** Lookaside allocations are only allowed for objects that are associated
+** with a particular database connection.  Hence, schema information cannot
+** be stored in lookaside because in shared cache mode the schema information
+** is shared by multiple database connections.  Therefore, while parsing
+** schema information, the Lookaside.bEnabled flag is cleared so that
+** lookaside allocations are not used to construct the schema objects.
 */
 struct Lookaside {
   u16 sz;                 /* Size of each buffer in bytes */
-  u8 bEnabled;            /* True if use lookaside.  False to ignore it */
+  u8 bEnabled;            /* False to disable new lookaside allocations */
   u8 bMalloced;           /* True if pStart obtained from sqlite3_malloc() */
   int nOut;               /* Number of buffers currently checked out */
   int mxOut;              /* Highwater mark for nOut */
+  int anStat[3];          /* 0: hits.  1: size misses.  2: full misses */
   LookasideSlot *pFree;   /* List of available buffers */
   void *pStart;           /* First byte of available memory space */
   void *pEnd;             /* First byte past end of available space */
@@ -9205,65 +9811,44 @@ struct FuncDefHash {
 };
 
 /*
-** Each database is an instance of the following structure.
-**
-** The sqlite.lastRowid records the last insert rowid generated by an
-** insert statement.  Inserts on views do not affect its value.  Each
-** trigger has its own context, so that lastRowid can be updated inside
-** triggers as usual.  The previous value will be restored once the trigger
-** exits.  Upon entering a before or instead of trigger, lastRowid is no
-** longer (since after version 2.8.12) reset to -1.
-**
-** The sqlite.nChange does not count changes within triggers and keeps no
-** context.  It is reset at start of sqlite3_exec.
-** The sqlite.lsChange represents the number of changes made by the last
-** insert, update, or delete statement.  It remains constant throughout the
-** length of a statement and is then updated by OP_SetCounts.  It keeps a
-** context stack just like lastRowid so that the count of changes
-** within a trigger is not seen outside the trigger.  Changes to views do not
-** affect the value of lsChange.
-** The sqlite.csChange keeps track of the number of current changes (since
-** the last statement) and is used to update sqlite_lsChange.
-**
-** The member variables sqlite.errCode, sqlite.zErrMsg and sqlite.zErrMsg16
-** store the most recent error code and, if applicable, string. The
-** internal function sqlite3Error() is used to set these variables
-** consistently.
+** Each database connection is an instance of the following structure.
 */
 struct sqlite3 {
   sqlite3_vfs *pVfs;            /* OS Interface */
-  int nDb;                      /* Number of backends currently in use */
+  struct Vdbe *pVdbe;           /* List of active virtual machines */
+  CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
+  sqlite3_mutex *mutex;         /* Connection mutex */
   Db *aDb;                      /* All backends */
+  int nDb;                      /* Number of backends currently in use */
   int flags;                    /* Miscellaneous flags. See below */
-  int openFlags;                /* Flags passed to sqlite3_vfs.xOpen() */
+  i64 lastRowid;                /* ROWID of most recent insert (see above) */
+  unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
   int errCode;                  /* Most recent error code (SQLITE_*) */
   int errMask;                  /* & result codes with this before returning */
   u8 autoCommit;                /* The auto-commit flag. */
   u8 temp_store;                /* 1: file 2: memory 0: default */
   u8 mallocFailed;              /* True if we have seen a malloc failure */
   u8 dfltLockMode;              /* Default locking-mode for attached dbs */
-  u8 dfltJournalMode;           /* Default journal mode for attached dbs */
   signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
+  u8 suppressErr;               /* Do not issue error messages if true */
+  u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
+  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
   int nextPagesize;             /* Pagesize after VACUUM if >0 */
-  int nTable;                   /* Number of tables in the database */
-  CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
-  i64 lastRowid;                /* ROWID of most recent insert (see above) */
-  i64 priorNewRowid;            /* Last randomly generated ROWID */
   u32 magic;                    /* Magic number for detect library misuse */
   int nChange;                  /* Value returned by sqlite3_changes() */
   int nTotalChange;             /* Value returned by sqlite3_total_changes() */
-  sqlite3_mutex *mutex;         /* Connection mutex */
   int aLimit[SQLITE_N_LIMIT];   /* Limits */
   struct sqlite3InitInfo {      /* Information used during initialization */
-    int iDb;                    /* When back is being initialized */
     int newTnum;                /* Rootpage of table being initialized */
+    u8 iDb;                     /* Which db file is being initialized */
     u8 busy;                    /* TRUE if currently initializing */
+    u8 orphanTrigger;           /* Last statement is orphaned TEMP trigger */
   } init;
-  int nExtension;               /* Number of loaded extensions */
-  void **aExtension;            /* Array of shared library handles */
-  struct Vdbe *pVdbe;           /* List of active virtual machines */
   int activeVdbeCnt;            /* Number of VDBEs currently executing */
   int writeVdbeCnt;             /* Number of active VDBEs that are writing */
+  int vdbeExecCnt;              /* Number of nested calls to VdbeExec() */
+  int nExtension;               /* Number of loaded extensions */
+  void **aExtension;            /* Array of shared library handles */
   void (*xTrace)(void*,const char*);        /* Trace function */
   void *pTraceArg;                          /* Argument to the trace function */
   void (*xProfile)(void*,const char*,u64);  /* Profiling function */
@@ -9274,6 +9859,10 @@ struct sqlite3 {
   void (*xRollbackCallback)(void*); /* Invoked at every commit. */
   void *pUpdateArg;
   void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
+#ifndef SQLITE_OMIT_WAL
+  int (*xWalCallback)(void *, sqlite3 *, const char *, int);
+  void *pWalArg;
+#endif
   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
   void *pCollNeededArg;
@@ -9296,22 +9885,40 @@ struct sqlite3 {
   int nProgressOps;             /* Number of opcodes for progress callback */
 #endif
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-  Hash aModule;                 /* populated by sqlite3_create_module() */
-  Table *pVTab;                 /* vtab with active Connect/Create method */
-  sqlite3_vtab **aVTrans;       /* Virtual tables with open transactions */
   int nVTrans;                  /* Allocated size of aVTrans */
+  Hash aModule;                 /* populated by sqlite3_create_module() */
+  VtabCtx *pVtabCtx;            /* Context for active vtab connect/create */
+  VTable **aVTrans;             /* Virtual tables with open transactions */
+  VTable *pDisconnect;    /* Disconnect these in next sqlite3_prepare() */
 #endif
   FuncDefHash aFunc;            /* Hash table of connection functions */
   Hash aCollSeq;                /* All collating sequences */
   BusyHandler busyHandler;      /* Busy callback */
-  int busyTimeout;              /* Busy handler timeout, in msec */
   Db aDbStatic[2];              /* Static space for the 2 default backends */
-#ifdef SQLITE_SSE
-  sqlite3_stmt *pFetch;         /* Used by SSE to fetch stored statements */
-#endif
   Savepoint *pSavepoint;        /* List of active savepoints */
+  int busyTimeout;              /* Busy handler timeout, in msec */
   int nSavepoint;               /* Number of non-transaction savepoints */
-  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
+  int nStatement;               /* Number of nested statement-transactions  */
+  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
+  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */
+
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  /* The following variables are all protected by the STATIC_MASTER 
+  ** mutex, not by sqlite3.mutex. They are used by code in notify.c. 
+  **
+  ** When X.pUnlockConnection==Y, that means that X is waiting for Y to
+  ** unlock so that it can proceed.
+  **
+  ** When X.pBlockingConnection==Y, that means that something that X tried
+  ** tried to do recently failed with an SQLITE_LOCKED error due to locks
+  ** held by Y.
+  */
+  sqlite3 *pBlockingConnection; /* Connection that caused SQLITE_LOCKED */
+  sqlite3 *pUnlockConnection;           /* Connection to watch for unlock */
+  void *pUnlockArg;                     /* Argument to xUnlockNotify */
+  void (*xUnlockNotify)(void **, int);  /* Unlock notify callback */
+  sqlite3 *pNextBlocked;        /* Next in list of all blocked connections */
+#endif
 };
 
 /*
@@ -9320,37 +9927,50 @@ struct sqlite3 {
 #define ENC(db) ((db)->aDb[0].pSchema->enc)
 
 /*
-** Possible values for the sqlite.flags and or Db.flags fields.
-**
-** On sqlite.flags, the SQLITE_InTrans value means that we have
-** executed a BEGIN.  On Db.flags, SQLITE_InTrans means a statement
-** transaction is active on that particular database file.
+** Possible values for the sqlite3.flags.
 */
-#define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
-#define SQLITE_InTrans        0x00000008  /* True if in a transaction */
-#define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
-#define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
-#define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
-#define SQLITE_CountRows      0x00000080  /* Count rows changed by INSERT, */
+#define SQLITE_VdbeTrace      0x00000100  /* True to trace VDBE execution */
+#define SQLITE_InternChanges  0x00000200  /* Uncommitted Hash table changes */
+#define SQLITE_FullColNames   0x00000400  /* Show full column names on SELECT */
+#define SQLITE_ShortColNames  0x00000800  /* Show short columns names */
+#define SQLITE_CountRows      0x00001000  /* Count rows changed by INSERT, */
                                           /*   DELETE, or UPDATE and return */
                                           /*   the count using a callback. */
-#define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
+#define SQLITE_NullCallback   0x00002000  /* Invoke the callback once if the */
                                           /*   result set is empty */
-#define SQLITE_SqlTrace       0x00000200  /* Debug print SQL as it executes */
-#define SQLITE_VdbeListing    0x00000400  /* Debug listings of VDBE programs */
-#define SQLITE_WriteSchema    0x00000800  /* OK to update SQLITE_MASTER */
-#define SQLITE_NoReadlock     0x00001000  /* Readlocks are omitted when 
-                                          ** accessing read-only databases */
-#define SQLITE_IgnoreChecks   0x00002000  /* Do not enforce check constraints */
-#define SQLITE_ReadUncommitted 0x00004000 /* For shared-cache mode */
-#define SQLITE_LegacyFileFmt  0x00008000  /* Create new databases in format 1 */
-#define SQLITE_FullFSync      0x00010000  /* Use full fsync on the backend */
-#define SQLITE_LoadExtension  0x00020000  /* Enable load_extension */
+#define SQLITE_SqlTrace       0x00004000  /* Debug print SQL as it executes */
+#define SQLITE_VdbeListing    0x00008000  /* Debug listings of VDBE programs */
+#define SQLITE_WriteSchema    0x00010000  /* OK to update SQLITE_MASTER */
+                         /*   0x00020000  Unused */
+#define SQLITE_IgnoreChecks   0x00040000  /* Do not enforce check constraints */
+#define SQLITE_ReadUncommitted 0x0080000  /* For shared-cache mode */
+#define SQLITE_LegacyFileFmt  0x00100000  /* Create new databases in format 1 */
+#define SQLITE_FullFSync      0x00200000  /* Use full fsync on the backend */
+#define SQLITE_CkptFullFSync  0x00400000  /* Use full fsync for checkpoint */
+#define SQLITE_RecoveryMode   0x00800000  /* Ignore schema errors */
+#define SQLITE_ReverseOrder   0x01000000  /* Reverse unordered SELECTs */
+#define SQLITE_RecTriggers    0x02000000  /* Enable recursive triggers */
+#define SQLITE_ForeignKeys    0x04000000  /* Enforce foreign key constraints  */
+#define SQLITE_AutoIndex      0x08000000  /* Enable automatic indexes */
+#define SQLITE_PreferBuiltin  0x10000000  /* Preference to built-in funcs */
+#define SQLITE_LoadExtension  0x20000000  /* Enable load_extension */
+#define SQLITE_EnableTrigger  0x40000000  /* True to enable triggers */
 
-#define SQLITE_RecoveryMode   0x00040000  /* Ignore schema errors */
-#define SQLITE_SharedCache    0x00080000  /* Cache sharing is enabled */
-#define SQLITE_Vtab           0x00100000  /* There exists a virtual table */
-#define SQLITE_CommitBusy     0x00200000  /* In the process of committing */
+/*
+** Bits of the sqlite3.flags field that are used by the
+** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface.
+** These must be the low-order bits of the flags field.
+*/
+#define SQLITE_QueryFlattener 0x01        /* Disable query flattening */
+#define SQLITE_ColumnCache    0x02        /* Disable the column cache */
+#define SQLITE_IndexSort      0x04        /* Disable indexes for sorting */
+#define SQLITE_IndexSearch    0x08        /* Disable indexes for searching */
+#define SQLITE_IndexCover     0x10        /* Disable index covering table */
+#define SQLITE_GroupByOrder   0x20        /* Disable GROUPBY cover of ORDERBY */
+#define SQLITE_FactorOutConst 0x40        /* Disable factoring out constants */
+#define SQLITE_IdxRealAsInt   0x80        /* Store REAL as INT in indices */
+#define SQLITE_DistinctOpt    0x80        /* DISTINCT using indexes */
+#define SQLITE_OptMask        0xff        /* Mask of all disablable opts */
 
 /*
 ** Possible values for the sqlite.magic field.
@@ -9362,6 +9982,7 @@ struct sqlite3 {
 #define SQLITE_MAGIC_SICK     0x4b771290  /* Error and awaiting close */
 #define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
 #define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */
+#define SQLITE_MAGIC_ZOMBIE   0x64cffc7f  /* Close with last statement close */
 
 /*
 ** Each SQL function is defined by an instance of the following
@@ -9380,16 +10001,42 @@ struct FuncDef {
   void (*xFinalize)(sqlite3_context*);                /* Aggregate finalizer */
   char *zName;         /* SQL name of the function. */
   FuncDef *pHash;      /* Next with a different name but the same hash */
+  FuncDestructor *pDestructor;   /* Reference counted destructor function */
 };
 
 /*
-** Possible values for FuncDef.flags
+** This structure encapsulates a user-function destructor callback (as
+** configured using create_function_v2()) and a reference counter. When
+** create_function_v2() is called to create a function with a destructor,
+** a single object of this type is allocated. FuncDestructor.nRef is set to 
+** the number of FuncDef objects created (either 1 or 3, depending on whether
+** or not the specified encoding is SQLITE_ANY). The FuncDef.pDestructor
+** member of each of the new FuncDef objects is set to point to the allocated
+** FuncDestructor.
+**
+** Thereafter, when one of the FuncDef objects is deleted, the reference
+** count on this object is decremented. When it reaches 0, the destructor
+** is invoked and the FuncDestructor structure freed.
+*/
+struct FuncDestructor {
+  int nRef;
+  void (*xDestroy)(void *);
+  void *pUserData;
+};
+
+/*
+** Possible values for FuncDef.flags.  Note that the _LENGTH and _TYPEOF
+** values must correspond to OPFLAG_LENGTHARG and OPFLAG_TYPEOFARG.  There
+** are assert() statements in the code to verify this.
 */
 #define SQLITE_FUNC_LIKE     0x01 /* Candidate for the LIKE optimization */
 #define SQLITE_FUNC_CASE     0x02 /* Case-sensitive LIKE-type function */
 #define SQLITE_FUNC_EPHEM    0x04 /* Ephemeral.  Delete with VDBE */
 #define SQLITE_FUNC_NEEDCOLL 0x08 /* sqlite3GetFuncCollSeq() might be called */
-#define SQLITE_FUNC_PRIVATE  0x10 /* Allowed for internal use only */
+#define SQLITE_FUNC_COUNT    0x10 /* Built-in count(*) aggregate */
+#define SQLITE_FUNC_COALESCE 0x20 /* Built-in coalesce() or ifnull() function */
+#define SQLITE_FUNC_LENGTH   0x40 /* Built-in length() function */
+#define SQLITE_FUNC_TYPEOF   0x80 /* Built-in typeof() function */
 
 /*
 ** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
@@ -9400,7 +10047,7 @@ struct FuncDef {
 **     implemented by C function xFunc that accepts nArg arguments. The
 **     value passed as iArg is cast to a (void*) and made available
 **     as the user-data (sqlite3_user_data()) for the function. If 
-**     argument bNC is true, then the FuncDef.needCollate flag is set.
+**     argument bNC is true, then the SQLITE_FUNC_NEEDCOLL flag is set.
 **
 **   AGGREGATE(zName, nArg, iArg, bNC, xStep, xFinal)
 **     Used to create an aggregate function definition implemented by
@@ -9417,13 +10064,19 @@ struct FuncDef {
 **     parameter.
 */
 #define FUNCTION(zName, nArg, iArg, bNC, xFunc) \
-  {nArg, SQLITE_UTF8, bNC*8, SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0}
+  {nArg, SQLITE_UTF8, (bNC*SQLITE_FUNC_NEEDCOLL), \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
+#define FUNCTION2(zName, nArg, iArg, bNC, xFunc, extraFlags) \
+  {nArg, SQLITE_UTF8, (bNC*SQLITE_FUNC_NEEDCOLL)|extraFlags, \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
 #define STR_FUNCTION(zName, nArg, pArg, bNC, xFunc) \
-  {nArg, SQLITE_UTF8, bNC*8, pArg, 0, xFunc, 0, 0, #zName, 0}
+  {nArg, SQLITE_UTF8, bNC*SQLITE_FUNC_NEEDCOLL, \
+   pArg, 0, xFunc, 0, 0, #zName, 0, 0}
 #define LIKEFUNC(zName, nArg, arg, flags) \
-  {nArg, SQLITE_UTF8, flags, (void *)arg, 0, likeFunc, 0, 0, #zName, 0}
+  {nArg, SQLITE_UTF8, flags, (void *)arg, 0, likeFunc, 0, 0, #zName, 0, 0}
 #define AGGREGATE(zName, nArg, arg, nc, xStep, xFinal) \
-  {nArg, SQLITE_UTF8, nc*8, SQLITE_INT_TO_PTR(arg), 0, 0, xStep,xFinal,#zName,0}
+  {nArg, SQLITE_UTF8, nc*SQLITE_FUNC_NEEDCOLL, \
+   SQLITE_INT_TO_PTR(arg), 0, 0, xStep,xFinal,#zName,0,0}
 
 /*
 ** All current savepoints are stored in a linked list starting at
@@ -9433,6 +10086,7 @@ struct FuncDef {
 */
 struct Savepoint {
   char *zName;                        /* Savepoint name (nul-terminated) */
+  i64 nDeferredCons;                  /* Number of deferred fk violations */
   Savepoint *pNext;                   /* Parent savepoint (if any) */
 };
 
@@ -9464,6 +10118,7 @@ struct Module {
 struct Column {
   char *zName;     /* Name of this column */
   Expr *pDflt;     /* Default value of this column */
+  char *zDflt;     /* Original text of the default value */
   char *zType;     /* Data type for this column */
   char *zColl;     /* Collating sequence.  If NULL, use the default */
   u8 notNull;      /* True if there is a NOT NULL constraint */
@@ -9498,20 +10153,11 @@ struct Column {
 struct CollSeq {
   char *zName;          /* Name of the collating sequence, UTF-8 encoded */
   u8 enc;               /* Text encoding handled by xCmp() */
-  u8 type;              /* One of the SQLITE_COLL_... values below */
   void *pUser;          /* First argument to xCmp() */
   int (*xCmp)(void*,int, const void*, int, const void*);
   void (*xDel)(void*);  /* Destructor for pUser */
 };
 
-/*
-** Allowed values of CollSeq.type:
-*/
-#define SQLITE_COLL_BINARY  1  /* The default memcmp() collating sequence */
-#define SQLITE_COLL_NOCASE  2  /* The built-in NOCASE collating sequence */
-#define SQLITE_COLL_REVERSE 3  /* The built-in REVERSE collating sequence */
-#define SQLITE_COLL_USER    0  /* Any other user-defined collating sequence */
-
 /*
 ** A sort order can be either ASC or DESC.
 */
@@ -9552,6 +10198,59 @@ struct CollSeq {
 */
 #define SQLITE_JUMPIFNULL   0x08  /* jumps if either operand is NULL */
 #define SQLITE_STOREP2      0x10  /* Store result in reg[P2] rather than jump */
+#define SQLITE_NULLEQ       0x80  /* NULL=NULL */
+
+/*
+** An object of this type is created for each virtual table present in
+** the database schema. 
+**
+** If the database schema is shared, then there is one instance of this
+** structure for each database connection (sqlite3*) that uses the shared
+** schema. This is because each database connection requires its own unique
+** instance of the sqlite3_vtab* handle used to access the virtual table 
+** implementation. sqlite3_vtab* handles can not be shared between 
+** database connections, even when the rest of the in-memory database 
+** schema is shared, as the implementation often stores the database
+** connection handle passed to it via the xConnect() or xCreate() method
+** during initialization internally. This database connection handle may
+** then be used by the virtual table implementation to access real tables 
+** within the database. So that they appear as part of the callers 
+** transaction, these accesses need to be made via the same database 
+** connection as that used to execute SQL operations on the virtual table.
+**
+** All VTable objects that correspond to a single table in a shared
+** database schema are initially stored in a linked-list pointed to by
+** the Table.pVTable member variable of the corresponding Table object.
+** When an sqlite3_prepare() operation is required to access the virtual
+** table, it searches the list for the VTable that corresponds to the
+** database connection doing the preparing so as to use the correct
+** sqlite3_vtab* handle in the compiled query.
+**
+** When an in-memory Table object is deleted (for example when the
+** schema is being reloaded for some reason), the VTable objects are not 
+** deleted and the sqlite3_vtab* handles are not xDisconnect()ed 
+** immediately. Instead, they are moved from the Table.pVTable list to
+** another linked list headed by the sqlite3.pDisconnect member of the
+** corresponding sqlite3 structure. They are then deleted/xDisconnected 
+** next time a statement is prepared using said sqlite3*. This is done
+** to avoid deadlock issues involving multiple sqlite3.mutex mutexes.
+** Refer to comments above function sqlite3VtabUnlockList() for an
+** explanation as to why it is safe to add an entry to an sqlite3.pDisconnect
+** list without holding the corresponding sqlite3.mutex mutex.
+**
+** The memory for objects of this type is always allocated by 
+** sqlite3DbMalloc(), using the connection handle stored in VTable.db as 
+** the first argument.
+*/
+struct VTable {
+  sqlite3 *db;              /* Database connection associated with this table */
+  Module *pMod;             /* Pointer to module implementation */
+  sqlite3_vtab *pVtab;      /* Pointer to vtab instance */
+  int nRef;                 /* Number of pointers to this structure */
+  u8 bConstraint;           /* True if constraints are supported */
+  int iSavepoint;           /* Depth of the SAVEPOINT stack */
+  VTable *pNext;            /* Next in linked list (see above) */
+};
 
 /*
 ** Each SQL table is represented in memory by an instance of the
@@ -9584,32 +10283,31 @@ struct CollSeq {
 ** of a SELECT statement.
 */
 struct Table {
-  sqlite3 *db;         /* Associated database connection.  Might be NULL. */
   char *zName;         /* Name of the table or view */
   int iPKey;           /* If not negative, use aCol[iPKey] as the primary key */
   int nCol;            /* Number of columns in this table */
   Column *aCol;        /* Information about each column */
   Index *pIndex;       /* List of SQL indexes on this table. */
   int tnum;            /* Root BTree node for this table (see note above) */
+  tRowcnt nRowEst;     /* Estimated rows in table - from sqlite_stat1 table */
   Select *pSelect;     /* NULL for tables.  Points to definition if a view. */
   u16 nRef;            /* Number of pointers to this Table */
   u8 tabFlags;         /* Mask of TF_* values */
   u8 keyConf;          /* What to do in case of uniqueness conflict on iPKey */
-  Trigger *pTrigger;   /* List of SQL triggers on this table */
   FKey *pFKey;         /* Linked list of all foreign keys in this table */
   char *zColAff;       /* String defining the affinity of each column */
 #ifndef SQLITE_OMIT_CHECK
-  Expr *pCheck;        /* The AND of all CHECK constraints */
+  ExprList *pCheck;    /* All CHECK constraints */
 #endif
 #ifndef SQLITE_OMIT_ALTERTABLE
   int addColOffset;    /* Offset in CREATE TABLE stmt to add a new column */
 #endif
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-  Module *pMod;        /* Pointer to the implementation of the module */
-  sqlite3_vtab *pVtab; /* Pointer to the module instance */
+  VTable *pVTable;     /* List of VTable objects. */
   int nModuleArg;      /* Number of arguments to the module */
   char **azModuleArg;  /* Text of all module args. [0] is module name */
 #endif
+  Trigger *pTrigger;   /* List of triggers stored in pSchema */
   Schema *pSchema;     /* Schema that contains this table */
   Table *pNextZombie;  /* Next on the Parse.pZombieTab list */
 };
@@ -9622,8 +10320,6 @@ struct Table {
 #define TF_HasPrimaryKey   0x04    /* Table has a primary key */
 #define TF_Autoincrement   0x08    /* Integer primary key is autoincrement */
 #define TF_Virtual         0x10    /* Is a virtual table */
-#define TF_NeedMetadata    0x20    /* aCol[].zType and aCol[].pColl missing */
-
 
 
 /*
@@ -9656,28 +10352,23 @@ struct Table {
 **
 ** Each REFERENCES clause generates an instance of the following structure
 ** which is attached to the from-table.  The to-table need not exist when
-** the from-table is created.  The existence of the to-table is not checked
-** until an attempt is made to insert data into the from-table.
-**
-** The sqlite.aFKey hash table stores pointers to this structure
-** given the name of a to-table.  For each to-table, all foreign keys
-** associated with that table are on a linked list using the FKey.pNextTo
-** field.
+** the from-table is created.  The existence of the to-table is not checked.
 */
 struct FKey {
-  Table *pFrom;     /* The table that contains the REFERENCES clause */
+  Table *pFrom;     /* Table containing the REFERENCES clause (aka: Child) */
   FKey *pNextFrom;  /* Next foreign key in pFrom */
-  char *zTo;        /* Name of table that the key points to */
-  FKey *pNextTo;    /* Next foreign key that points to zTo */
+  char *zTo;        /* Name of table that the key points to (aka: Parent) */
+  FKey *pNextTo;    /* Next foreign key on table named zTo */
+  FKey *pPrevTo;    /* Previous foreign key on table named zTo */
   int nCol;         /* Number of columns in this key */
+  /* EV: R-30323-21917 */
+  u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
+  u8 aAction[2];          /* ON DELETE and ON UPDATE actions, respectively */
+  Trigger *apTrigger[2];  /* Triggers for aAction[] actions */
   struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */
     int iFrom;         /* Index of column in pFrom */
     char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */
-  } *aCol;          /* One entry for each of nCol column s */
-  u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
-  u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */
-  u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */
-  u8 insertConf;    /* How to resolve conflicts that occur on INSERT */
+  } aCol[1];        /* One entry for each of nCol column s */
 };
 
 /*
@@ -9727,9 +10418,9 @@ struct FKey {
 */
 struct KeyInfo {
   sqlite3 *db;        /* The database connection */
-  u8 enc;             /* Text encoding - one of the TEXT_Utf* values */
+  u8 enc;             /* Text encoding - one of the SQLITE_UTF* values */
   u16 nField;         /* Number of entries in aColl[] */
-  u8 *aSortOrder;     /* If defined an aSortOrder[i] is true, sort DESC */
+  u8 *aSortOrder;     /* Sort order for each column.  May be NULL */
   CollSeq *aColl[1];  /* Collating sequence for each term of the key */
 };
 
@@ -9750,18 +10441,17 @@ struct KeyInfo {
 struct UnpackedRecord {
   KeyInfo *pKeyInfo;  /* Collation and sort-order information */
   u16 nField;         /* Number of entries in apMem[] */
-  u16 flags;          /* Boolean settings.  UNPACKED_... below */
+  u8 flags;           /* Boolean settings.  UNPACKED_... below */
+  i64 rowid;          /* Used by UNPACKED_PREFIX_SEARCH */
   Mem *aMem;          /* Values */
 };
 
 /*
 ** Allowed values of UnpackedRecord.flags
 */
-#define UNPACKED_NEED_FREE     0x0001  /* Memory is from sqlite3Malloc() */
-#define UNPACKED_NEED_DESTROY  0x0002  /* apMem[]s should all be destroyed */
-#define UNPACKED_IGNORE_ROWID  0x0004  /* Ignore trailing rowid on key1 */
-#define UNPACKED_INCRKEY       0x0008  /* Make this key an epsilon larger */
-#define UNPACKED_PREFIX_MATCH  0x0010  /* A prefix match is considered OK */
+#define UNPACKED_INCRKEY       0x01  /* Make this key an epsilon larger */
+#define UNPACKED_PREFIX_MATCH  0x02  /* A prefix match is considered OK */
+#define UNPACKED_PREFIX_SEARCH 0x04  /* Ignore final (rowid) field */
 
 /*
 ** Each SQL index is represented in memory by an
@@ -9791,18 +10481,42 @@ struct UnpackedRecord {
 */
 struct Index {
   char *zName;     /* Name of this index */
-  int nColumn;     /* Number of columns in the table used by this index */
   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
-  unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
+  tRowcnt *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
   Table *pTable;   /* The SQL table being indexed */
-  int tnum;        /* Page containing root of this index in database file */
-  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
-  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
   char *zColAff;   /* String defining the affinity of each column */
   Index *pNext;    /* The next index associated with the same table */
   Schema *pSchema; /* Schema containing this index */
   u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */
   char **azColl;   /* Array of collation sequence names for index */
+  int nColumn;     /* Number of columns in the table used by this index */
+  int tnum;        /* Page containing root of this index in database file */
+  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
+  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
+  u8 bUnordered;   /* Use this index for == or IN queries only */
+#ifdef SQLITE_ENABLE_STAT3
+  int nSample;             /* Number of elements in aSample[] */
+  tRowcnt avgEq;           /* Average nEq value for key values not in aSample */
+  IndexSample *aSample;    /* Samples of the left-most key */
+#endif
+};
+
+/*
+** Each sample stored in the sqlite_stat3 table is represented in memory 
+** using a structure of this type.  See documentation at the top of the
+** analyze.c source file for additional information.
+*/
+struct IndexSample {
+  union {
+    char *z;        /* Value if eType is SQLITE_TEXT or SQLITE_BLOB */
+    double r;       /* Value if eType is SQLITE_FLOAT */
+    i64 i;          /* Value if eType is SQLITE_INTEGER */
+  } u;
+  u8 eType;         /* SQLITE_NULL, SQLITE_INTEGER ... etc. */
+  int nByte;        /* Size in byte of text or blob. */
+  tRowcnt nEq;      /* Est. number of rows where the key equals this sample */
+  tRowcnt nLt;      /* Est. number of rows where key is less than this sample */
+  tRowcnt nDLt;     /* Est. number of distinct keys less than this sample */
 };
 
 /*
@@ -9814,9 +10528,8 @@ struct Index {
 ** and Token.n when Token.z==0.
 */
 struct Token {
-  const unsigned char *z; /* Text of the token.  Not NULL-terminated! */
-  unsigned dyn  : 1;      /* True for malloced memory, false for static */
-  unsigned n    : 31;     /* Number of characters in this token */
+  const char *z;     /* Text of the token.  Not NULL-terminated! */
+  unsigned int n;    /* Number of characters in this token */
 };
 
 /*
@@ -9838,8 +10551,9 @@ struct AggInfo {
   u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
                           ** than the source table */
   int sortingIdx;         /* Cursor number of the sorting index */
-  ExprList *pGroupBy;     /* The group by clause */
+  int sortingIdxPTab;     /* Cursor number of pseudo-table */
   int nSortingColumn;     /* Number of columns in the sorting index */
+  ExprList *pGroupBy;     /* The group by clause */
   struct AggInfo_col {    /* For each column used in source tables */
     Table *pTab;             /* Source table */
     int iTable;              /* Cursor number of the source table */
@@ -9849,7 +10563,6 @@ struct AggInfo {
     Expr *pExpr;             /* The original expression */
   } *aCol;
   int nColumn;            /* Number of used entries in aCol[] */
-  int nColumnAlloc;       /* Number of slots allocated for aCol[] */
   int nAccumulator;       /* Number of columns that show through to the output.
                           ** Additional columns are used only as parameters to
                           ** aggregate functions */
@@ -9860,26 +10573,49 @@ struct AggInfo {
     int iDistinct;           /* Ephemeral table used to enforce DISTINCT */
   } *aFunc;
   int nFunc;              /* Number of entries in aFunc[] */
-  int nFuncAlloc;         /* Number of slots allocated for aFunc[] */
 };
 
+/*
+** The datatype ynVar is a signed integer, either 16-bit or 32-bit.
+** Usually it is 16-bits.  But if SQLITE_MAX_VARIABLE_NUMBER is greater
+** than 32767 we have to make it 32-bit.  16-bit is preferred because
+** it uses less memory in the Expr object, which is a big memory user
+** in systems with lots of prepared statements.  And few applications
+** need more than about 10 or 20 variables.  But some extreme users want
+** to have prepared statements with over 32767 variables, and for them
+** the option is available (at compile-time).
+*/
+#if SQLITE_MAX_VARIABLE_NUMBER<=32767
+typedef i16 ynVar;
+#else
+typedef int ynVar;
+#endif
+
 /*
 ** Each node of an expression in the parse tree is an instance
 ** of this structure.
 **
-** Expr.op is the opcode.  The integer parser token codes are reused
-** as opcodes here.  For example, the parser defines TK_GE to be an integer
-** code representing the ">=" operator.  This same integer code is reused
+** Expr.op is the opcode. The integer parser token codes are reused
+** as opcodes here. For example, the parser defines TK_GE to be an integer
+** code representing the ">=" operator. This same integer code is reused
 ** to represent the greater-than-or-equal-to operator in the expression
 ** tree.
 **
-** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
-** of argument if the expression is a function.
+** If the expression is an SQL literal (TK_INTEGER, TK_FLOAT, TK_BLOB, 
+** or TK_STRING), then Expr.token contains the text of the SQL literal. If
+** the expression is a variable (TK_VARIABLE), then Expr.token contains the 
+** variable name. Finally, if the expression is an SQL function (TK_FUNCTION),
+** then Expr.token contains the name of the function.
 **
-** Expr.token is the operator token for this node.  For some expressions
-** that have subexpressions, Expr.token can be the complete text that gave
-** rise to the Expr.  In the latter case, the token is marked as being
-** a compound token.
+** Expr.pRight and Expr.pLeft are the left and right subexpressions of a
+** binary operator. Either or both may be NULL.
+**
+** Expr.x.pList is a list of arguments if the expression is an SQL function,
+** a CASE expression or an IN expression of the form "<lhs> IN (<y>, <z>...)".
+** Expr.x.pSelect is used if the expression is a sub-select or an expression of
+** the form "<lhs> IN (SELECT ...)". If the EP_xIsSelect bit is set in the
+** Expr.flags mask, then Expr.x.pSelect is valid. Otherwise, Expr.x.pList is 
+** valid.
 **
 ** An expression of the form ID or ID.ID refers to a column in a table.
 ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
@@ -9889,10 +10625,9 @@ struct AggInfo {
 ** value is also stored in the Expr.iAgg column in the aggregate so that
 ** it can be accessed after all aggregates are computed.
 **
-** If the expression is a function, the Expr.iTable is an integer code
-** representing which function.  If the expression is an unbound variable
-** marker (a question mark character '?' in the original SQL) then the
-** Expr.iTable holds the index number for that variable.
+** If the expression is an unbound variable marker (a question mark 
+** character '?' in the original SQL) then the Expr.iTable holds the index 
+** number for that variable.
 **
 ** If the expression is a subquery then Expr.iColumn holds an integer
 ** register number containing the result of the subquery.  If the
@@ -9900,32 +10635,64 @@ struct AggInfo {
 ** gives a different answer at different times during statement processing
 ** then iTable is the address of a subroutine that computes the subquery.
 **
-** The Expr.pSelect field points to a SELECT statement.  The SELECT might
-** be the right operand of an IN operator.  Or, if a scalar SELECT appears
-** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
-** operand.
-**
 ** If the Expr is of type OP_Column, and the table it is selecting from
 ** is a disk table or the "old.*" pseudo-table, then pTab points to the
 ** corresponding table definition.
+**
+** ALLOCATION NOTES:
+**
+** Expr objects can use a lot of memory space in database schema.  To
+** help reduce memory requirements, sometimes an Expr object will be
+** truncated.  And to reduce the number of memory allocations, sometimes
+** two or more Expr objects will be stored in a single memory allocation,
+** together with Expr.zToken strings.
+**
+** If the EP_Reduced and EP_TokenOnly flags are set when
+** an Expr object is truncated.  When EP_Reduced is set, then all
+** the child Expr objects in the Expr.pLeft and Expr.pRight subtrees
+** are contained within the same memory allocation.  Note, however, that
+** the subtrees in Expr.x.pList or Expr.x.pSelect are always separately
+** allocated, regardless of whether or not EP_Reduced is set.
 */
 struct Expr {
   u8 op;                 /* Operation performed by this node */
   char affinity;         /* The affinity of the column or 0 if not a column */
-  u16 flags;             /* Various flags.  See below */
+  u16 flags;             /* Various flags.  EP_* See below */
+  union {
+    char *zToken;          /* Token value. Zero terminated and dequoted */
+    int iValue;            /* Non-negative integer value if EP_IntValue */
+  } u;
+
+  /* If the EP_TokenOnly flag is set in the Expr.flags mask, then no
+  ** space is allocated for the fields below this point. An attempt to
+  ** access them will result in a segfault or malfunction. 
+  *********************************************************************/
+
+  Expr *pLeft;           /* Left subnode */
+  Expr *pRight;          /* Right subnode */
+  union {
+    ExprList *pList;     /* Function arguments or in "<expr> IN (<expr-list)" */
+    Select *pSelect;     /* Used for sub-selects and "<expr> IN (<select>)" */
+  } x;
   CollSeq *pColl;        /* The collation type of the column or 0 */
-  Expr *pLeft, *pRight;  /* Left and right subnodes */
-  ExprList *pList;       /* A list of expressions used as function arguments
-                         ** or in "<expr> IN (<expr-list)" */
-  Token token;           /* An operand token */
-  Token span;            /* Complete text of the expression */
-  int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
-                         ** iColumn-th field of the iTable-th table. */
+
+  /* If the EP_Reduced flag is set in the Expr.flags mask, then no
+  ** space is allocated for the fields below this point. An attempt to
+  ** access them will result in a segfault or malfunction.
+  *********************************************************************/
+
+  int iTable;            /* TK_COLUMN: cursor number of table holding column
+                         ** TK_REGISTER: register number
+                         ** TK_TRIGGER: 1 -> new, 0 -> old */
+  ynVar iColumn;         /* TK_COLUMN: column index.  -1 for rowid.
+                         ** TK_VARIABLE: variable number (always >= 1). */
+  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
+  i16 iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
+  u8 flags2;             /* Second set of flags.  EP2_... */
+  u8 op2;                /* TK_REGISTER: original value of Expr.op
+                         ** TK_COLUMN: the value of p5 for OP_Column
+                         ** TK_AGG_FUNCTION: nesting depth */
   AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
-  int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
-  int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
-  Select *pSelect;       /* When the expression is a sub-select.  Also the
-                         ** right side of "<expr> IN (<select>)" */
   Table *pTab;           /* Table for TK_COLUMN expressions. */
 #if SQLITE_MAX_EXPR_DEPTH>0
   int nHeight;           /* Height of the tree headed by this node */
@@ -9941,12 +10708,35 @@ struct Expr {
 #define EP_Error      0x0008  /* Expression contains one or more errors */
 #define EP_Distinct   0x0010  /* Aggregate function with DISTINCT keyword */
 #define EP_VarSelect  0x0020  /* pSelect is correlated, not constant */
-#define EP_Dequoted   0x0040  /* True if the string has been dequoted */
+#define EP_DblQuoted  0x0040  /* token.z was originally in "..." */
 #define EP_InfixFunc  0x0080  /* True for an infix function: LIKE, GLOB, etc */
 #define EP_ExpCollate 0x0100  /* Collating sequence specified explicitly */
-#define EP_AnyAff     0x0200  /* Can take a cached column of any affinity */
-#define EP_FixedDest  0x0400  /* Result needed in a specific register */
-#define EP_IntValue   0x0800  /* Integer value contained in iTable */
+#define EP_FixedDest  0x0200  /* Result needed in a specific register */
+#define EP_IntValue   0x0400  /* Integer value contained in u.iValue */
+#define EP_xIsSelect  0x0800  /* x.pSelect is valid (otherwise x.pList is) */
+#define EP_Hint       0x1000  /* Not used */
+#define EP_Reduced    0x2000  /* Expr struct is EXPR_REDUCEDSIZE bytes only */
+#define EP_TokenOnly  0x4000  /* Expr struct is EXPR_TOKENONLYSIZE bytes only */
+#define EP_Static     0x8000  /* Held in memory not obtained from malloc() */
+
+/*
+** The following are the meanings of bits in the Expr.flags2 field.
+*/
+#define EP2_MallocedToken  0x0001  /* Need to sqlite3DbFree() Expr.zToken */
+#define EP2_Irreducible    0x0002  /* Cannot EXPRDUP_REDUCE this Expr */
+
+/*
+** The pseudo-routine sqlite3ExprSetIrreducible sets the EP2_Irreducible
+** flag on an expression structure.  This flag is used for VV&A only.  The
+** routine is implemented as a macro that only works when in debugging mode,
+** so as not to burden production code.
+*/
+#ifdef SQLITE_DEBUG
+# define ExprSetIrreducible(X)  (X)->flags2 |= EP2_Irreducible
+#else
+# define ExprSetIrreducible(X)
+#endif
+
 /*
 ** These macros can be used to test, set, or clear bits in the 
 ** Expr.flags field.
@@ -9956,6 +10746,21 @@ struct Expr {
 #define ExprSetProperty(E,P)     (E)->flags|=(P)
 #define ExprClearProperty(E,P)   (E)->flags&=~(P)
 
+/*
+** Macros to determine the number of bytes required by a normal Expr 
+** struct, an Expr struct with the EP_Reduced flag set in Expr.flags 
+** and an Expr struct with the EP_TokenOnly flag set.
+*/
+#define EXPR_FULLSIZE           sizeof(Expr)           /* Full size */
+#define EXPR_REDUCEDSIZE        offsetof(Expr,iTable)  /* Common features */
+#define EXPR_TOKENONLYSIZE      offsetof(Expr,pLeft)   /* Fewer features */
+
+/*
+** Flags passed to the sqlite3ExprDup() function. See the header comment 
+** above sqlite3ExprDup() for details.
+*/
+#define EXPRDUP_REDUCE         0x0001  /* Used reduced-size Expr nodes */
+
 /*
 ** A list of expressions.  Each expression may optionally have a
 ** name.  An expr/name combination can be used in several ways, such
@@ -9966,16 +10771,27 @@ struct Expr {
 */
 struct ExprList {
   int nExpr;             /* Number of expressions on the list */
-  int nAlloc;            /* Number of entries allocated below */
   int iECursor;          /* VDBE Cursor associated with this ExprList */
-  struct ExprList_item {
+  struct ExprList_item { /* For each expression in the list */
     Expr *pExpr;           /* The list of expressions */
     char *zName;           /* Token associated with this expression */
+    char *zSpan;           /* Original text of the expression */
     u8 sortOrder;          /* 1 for DESC or 0 for ASC */
     u8 done;               /* A flag to indicate when processing is finished */
-    u16 iCol;              /* For ORDER BY, column number in result set */
+    u16 iOrderByCol;       /* For ORDER BY, column number in result set */
     u16 iAlias;            /* Index into Parse.aAlias[] for zName */
-  } *a;                  /* One entry for each expression */
+  } *a;                  /* Alloc a power of two greater or equal to nExpr */
+};
+
+/*
+** An instance of this structure is used by the parser to record both
+** the parse tree for an expression and the span of input text for an
+** expression.
+*/
+struct ExprSpan {
+  Expr *pExpr;          /* The expression parse tree */
+  const char *zStart;   /* First character of input text */
+  const char *zEnd;     /* One character past the end of input text */
 };
 
 /*
@@ -9999,7 +10815,6 @@ struct IdList {
     int idx;          /* Index in some Table.aCol[] of a column named zName */
   } *a;
   int nId;         /* Number of identifiers on the list */
-  int nAlloc;      /* Number of entries allocated for a[] below */
 };
 
 /*
@@ -10031,6 +10846,9 @@ typedef u64 Bitmask;
 ** and the next table on the list.  The parser builds the list this way.
 ** But sqlite3SrcListShiftJoinType() later shifts the jointypes so that each
 ** jointype expresses the join between the table and the previous table.
+**
+** In the colUsed field, the high-order bit (bit 63) is set if the table
+** contains more than 63 columns and the 64-th or later column is used.
 */
 struct SrcList {
   i16 nSrc;        /* Number of tables or subqueries in the FROM clause */
@@ -10041,9 +10859,14 @@ struct SrcList {
     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
     Table *pTab;      /* An SQL table corresponding to zName */
     Select *pSelect;  /* A SELECT statement used in place of a table name */
-    u8 isPopulated;   /* Temporary table associated with SELECT is populated */
+    int addrFillSub;  /* Address of subroutine to manifest a subquery */
+    int regReturn;    /* Register holding return address of addrFillSub */
     u8 jointype;      /* Type of join between this able and the previous */
     u8 notIndexed;    /* True if there is a NOT INDEXED clause */
+    u8 isCorrelated;  /* True if sub-query is correlated */
+#ifndef SQLITE_OMIT_EXPLAIN
+    u8 iSelectId;     /* If pSelect!=0, the id of the sub-select in EQP */
+#endif
     int iCursor;      /* The VDBE cursor number used to access this table */
     Expr *pOn;        /* The ON clause of a join */
     IdList *pUsing;   /* The USING clause of a join */
@@ -10082,6 +10905,7 @@ struct SrcList {
 struct WherePlan {
   u32 wsFlags;                   /* WHERE_* flags that describe the strategy */
   u32 nEq;                       /* Number of == constraints */
+  double nRow;                   /* Estimated number of rows (for EQP) */
   union {
     Index *pIdx;                   /* Index when WHERE_INDEXED is true */
     struct WhereTerm *pTerm;       /* WHERE clause term for OR-search */
@@ -10092,7 +10916,7 @@ struct WherePlan {
 /*
 ** For each nested loop in a WHERE clause implementation, the WhereInfo
 ** structure contains a single instance of this structure.  This structure
-** is intended to be private the the where.c module and should not be
+** is intended to be private to the where.c module and should not be
 ** access or modified by other modules.
 **
 ** The pIdxInfo field is used to help pick the best index on a
@@ -10122,9 +10946,7 @@ struct WhereLevel {
         int addrInTop;         /* Top of the IN loop */
       } *aInLoop;           /* Information about each nested IN operator */
     } in;                 /* Used when plan.wsFlags&WHERE_IN_ABLE */
-    struct {
-      WherePlan *aPlan;     /* Plans for each term of the WHERE clause */
-    } or;                 /* Used when plan.wsFlags&WHERE_MULTI_OR */
+    Index *pCovidx;       /* Possible covering index for WHERE_MULTI_OR */
   } u;
 
   /* The following field is really not part of the current level.  But
@@ -10137,15 +10959,18 @@ struct WhereLevel {
 };
 
 /*
-** Flags appropriate for the wctrlFlags parameter of sqlite3WhereBegin().
+** Flags appropriate for the wctrlFlags parameter of sqlite3WhereBegin()
+** and the WhereInfo.wctrlFlags member.
 */
 #define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
 #define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
 #define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
 #define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
-#define WHERE_FILL_ROWSET      0x0008  /* Save results in a RowSet object */
-#define WHERE_OMIT_OPEN        0x0010  /* Table cursor are already open */
-#define WHERE_OMIT_CLOSE       0x0020  /* Omit close of table & index cursors */
+#define WHERE_DUPLICATES_OK    0x0008 /* Ok to return a row more than once */
+#define WHERE_OMIT_OPEN_CLOSE  0x0010 /* Table cursors are already open */
+#define WHERE_FORCE_TABLE      0x0020 /* Do not use an index-only search */
+#define WHERE_ONETABLE_ONLY    0x0040 /* Only code the 1st table in pTabList */
+#define WHERE_AND_ONLY         0x0080 /* Don't use indices for OR terms */
 
 /*
 ** The WHERE clause processing routine has two halves.  The
@@ -10158,16 +10983,22 @@ struct WhereInfo {
   Parse *pParse;       /* Parsing and code generating context */
   u16 wctrlFlags;      /* Flags originally passed to sqlite3WhereBegin() */
   u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */
-  int regRowSet;                 /* Store rowids in this rowset if >=0 */
+  u8 untestedTerms;    /* Not all WHERE terms resolved by outer loop */
+  u8 eDistinct;
   SrcList *pTabList;             /* List of tables in the join */
   int iTop;                      /* The very beginning of the WHERE loop */
   int iContinue;                 /* Jump here to continue with next record */
   int iBreak;                    /* Jump here to break out of the loop */
   int nLevel;                    /* Number of nested loop */
   struct WhereClause *pWC;       /* Decomposition of the WHERE clause */
+  double savedNQueryLoop;        /* pParse->nQueryLoop outside the WHERE loop */
+  double nRowOut;                /* Estimated number of output rows */
   WhereLevel a[1];               /* Information about each nest loop in WHERE */
 };
 
+#define WHERE_DISTINCT_UNIQUE 1
+#define WHERE_DISTINCT_ORDERED 2
+
 /*
 ** A NameContext defines a context in which to resolve table and column
 ** names.  The context consists of a list of tables (the pSrcList) field and
@@ -10193,16 +11024,21 @@ struct NameContext {
   Parse *pParse;       /* The parser */
   SrcList *pSrcList;   /* One or more tables used to resolve names */
   ExprList *pEList;    /* Optional list of named expressions */
-  int nRef;            /* Number of names resolved by this context */
-  int nErr;            /* Number of errors encountered while resolving names */
-  u8 allowAgg;         /* Aggregate functions allowed here */
-  u8 hasAgg;           /* True if aggregates are seen */
-  u8 isCheck;          /* True if resolving names in a CHECK constraint */
-  int nDepth;          /* Depth of subquery recursion. 1 for no recursion */
   AggInfo *pAggInfo;   /* Information about aggregates at this level */
   NameContext *pNext;  /* Next outer name context.  NULL for outermost */
+  int nRef;            /* Number of names resolved by this context */
+  int nErr;            /* Number of errors encountered while resolving names */
+  u8 ncFlags;          /* Zero or more NC_* flags defined below */
 };
 
+/*
+** Allowed values for the NameContext, ncFlags field.
+*/
+#define NC_AllowAgg  0x01    /* Aggregate functions are allowed here */
+#define NC_HasAgg    0x02    /* One or more aggregate functions seen */
+#define NC_IsCheck   0x04    /* True if resolving names in a CHECK constraint */
+#define NC_InAggFunc 0x08    /* True if analyzing arguments to an agg func */
+
 /*
 ** An instance of the following structure contains all information
 ** needed to generate code for a single SELECT statement.
@@ -10228,6 +11064,9 @@ struct Select {
   u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
   char affinity;         /* MakeRecord with this affinity for SRT_Set */
   u16 selFlags;          /* Various SF_* values */
+  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
+  int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
+  double nSelectRow;     /* Estimated number of result rows */
   SrcList *pSrc;         /* The FROM clause */
   Expr *pWhere;          /* The WHERE clause */
   ExprList *pGroupBy;    /* The GROUP BY clause */
@@ -10238,20 +11077,20 @@ struct Select {
   Select *pRightmost;    /* Right-most select in a compound select statement */
   Expr *pLimit;          /* LIMIT expression. NULL means not used. */
   Expr *pOffset;         /* OFFSET expression. NULL means not used. */
-  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
-  int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
 };
 
 /*
 ** Allowed values for Select.selFlags.  The "SF" prefix stands for
 ** "Select Flag".
 */
-#define SF_Distinct        0x0001  /* Output should be DISTINCT */
-#define SF_Resolved        0x0002  /* Identifiers have been resolved */
-#define SF_Aggregate       0x0004  /* Contains aggregate functions */
-#define SF_UsesEphemeral   0x0008  /* Uses the OpenEphemeral opcode */
-#define SF_Expanded        0x0010  /* sqlite3SelectExpand() called on this */
-#define SF_HasTypeInfo     0x0020  /* FROM subqueries have Table metadata */
+#define SF_Distinct        0x01  /* Output should be DISTINCT */
+#define SF_Resolved        0x02  /* Identifiers have been resolved */
+#define SF_Aggregate       0x04  /* Contains aggregate functions */
+#define SF_UsesEphemeral   0x08  /* Uses the OpenEphemeral opcode */
+#define SF_Expanded        0x10  /* sqlite3SelectExpand() called on this */
+#define SF_HasTypeInfo     0x20  /* FROM subqueries have Table metadata */
+#define SF_UseSorter       0x40  /* Sort using a sorter */
+#define SF_Values          0x80  /* Synthesized from VALUES clause */
 
 
 /*
@@ -10280,12 +11119,70 @@ struct Select {
 typedef struct SelectDest SelectDest;
 struct SelectDest {
   u8 eDest;         /* How to dispose of the results */
-  u8 affinity;      /* Affinity used when eDest==SRT_Set */
-  int iParm;        /* A parameter used by the eDest disposal method */
-  int iMem;         /* Base register where results are written */
-  int nMem;         /* Number of registers allocated */
+  u8 affSdst;       /* Affinity used when eDest==SRT_Set */
+  int iSDParm;      /* A parameter used by the eDest disposal method */
+  int iSdst;        /* Base register where results are written */
+  int nSdst;        /* Number of registers allocated */
 };
 
+/*
+** During code generation of statements that do inserts into AUTOINCREMENT 
+** tables, the following information is attached to the Table.u.autoInc.p
+** pointer of each autoincrement table to record some side information that
+** the code generator needs.  We have to keep per-table autoincrement
+** information in case inserts are down within triggers.  Triggers do not
+** normally coordinate their activities, but we do need to coordinate the
+** loading and saving of autoincrement information.
+*/
+struct AutoincInfo {
+  AutoincInfo *pNext;   /* Next info block in a list of them all */
+  Table *pTab;          /* Table this info block refers to */
+  int iDb;              /* Index in sqlite3.aDb[] of database holding pTab */
+  int regCtr;           /* Memory register holding the rowid counter */
+};
+
+/*
+** Size of the column cache
+*/
+#ifndef SQLITE_N_COLCACHE
+# define SQLITE_N_COLCACHE 10
+#endif
+
+/*
+** At least one instance of the following structure is created for each 
+** trigger that may be fired while parsing an INSERT, UPDATE or DELETE
+** statement. All such objects are stored in the linked list headed at
+** Parse.pTriggerPrg and deleted once statement compilation has been
+** completed.
+**
+** A Vdbe sub-program that implements the body and WHEN clause of trigger
+** TriggerPrg.pTrigger, assuming a default ON CONFLICT clause of
+** TriggerPrg.orconf, is stored in the TriggerPrg.pProgram variable.
+** The Parse.pTriggerPrg list never contains two entries with the same
+** values for both pTrigger and orconf.
+**
+** The TriggerPrg.aColmask[0] variable is set to a mask of old.* columns
+** accessed (or set to 0 for triggers fired as a result of INSERT 
+** statements). Similarly, the TriggerPrg.aColmask[1] variable is set to
+** a mask of new.* columns used by the program.
+*/
+struct TriggerPrg {
+  Trigger *pTrigger;      /* Trigger this program was coded from */
+  TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
+  SubProgram *pProgram;   /* Program implementing pTrigger/orconf */
+  int orconf;             /* Default ON CONFLICT policy */
+  u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */
+};
+
+/*
+** The yDbMask datatype for the bitmask of all attached databases.
+*/
+#if SQLITE_MAX_ATTACHED>30
+  typedef sqlite3_uint64 yDbMask;
+#else
+  typedef unsigned int yDbMask;
+#endif
+
 /*
 ** An SQL parser context.  A copy of this structure is passed through
 ** the parser and down into all the parser action routine in order to
@@ -10304,16 +11201,18 @@ struct SelectDest {
 */
 struct Parse {
   sqlite3 *db;         /* The main database structure */
-  int rc;              /* Return code from execution */
   char *zErrMsg;       /* An error message */
   Vdbe *pVdbe;         /* An engine for executing database bytecode */
+  int rc;              /* Return code from execution */
   u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
-  u8 nameClash;        /* A permanent table name clashes with temp table name */
   u8 checkSchema;      /* Causes schema cookie check after an error */
   u8 nested;           /* Number of nested calls to the parser/code generator */
-  u8 parseError;       /* True after a parsing error.  Ticket #1794 */
   u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
   u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
+  u8 nColCache;        /* Number of entries in aColCache[] */
+  u8 iColCache;        /* Next entry in aColCache[] to replace */
+  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
+  u8 mayAbort;         /* True if statement may throw an ABORT exception */
   int aTempReg[8];     /* Holding area for temporary registers */
   int nRangeReg;       /* Size of the temporary register block */
   int iRangeReg;       /* First register in temporary register block */
@@ -10321,57 +11220,78 @@ struct Parse {
   int nTab;            /* Number of previously allocated VDBE cursors */
   int nMem;            /* Number of memory cells used so far */
   int nSet;            /* Number of sets used so far */
+  int nOnce;           /* Number of OP_Once instructions so far */
   int ckBase;          /* Base register of data during check constraints */
-  int disableColCache; /* True to disable adding to column cache */
-  int nColCache;       /* Number of entries in the column cache */
-  int iColCache;       /* Next entry of the cache to replace */
+  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
+  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */
   struct yColCache {
     int iTable;           /* Table cursor number */
     int iColumn;          /* Table column number */
-    char affChange;       /* True if this register has had an affinity change */
-    int iReg;             /* Register holding value of this column */
-  } aColCache[10];     /* One for each valid column cache entry */
-  u32 writeMask;       /* Start a write transaction on these databases */
-  u32 cookieMask;      /* Bitmask of schema verified databases */
+    u8 tempReg;           /* iReg is a temp register that needs to be freed */
+    int iLevel;           /* Nesting level */
+    int iReg;             /* Reg with value of this column. 0 means none. */
+    int lru;              /* Least recently used entry has the smallest value */
+  } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
+  yDbMask writeMask;   /* Start a write transaction on these databases */
+  yDbMask cookieMask;  /* Bitmask of schema verified databases */
   int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
   int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
+  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
+  int regRoot;         /* Register holding root page number for new objects */
+  int nMaxArg;         /* Max args passed to user function by sub-program */
+  Token constraintName;/* Name of the constraint currently being parsed */
 #ifndef SQLITE_OMIT_SHARED_CACHE
   int nTableLock;        /* Number of locks in aTableLock */
   TableLock *aTableLock; /* Required table locks for shared-cache mode */
 #endif
-  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
-  int regRoot;         /* Register holding root page number for new objects */
+  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */
+
+  /* Information used while coding trigger programs. */
+  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
+  Table *pTriggerTab;  /* Table triggers are being coded for */
+  double nQueryLoop;   /* Estimated number of iterations of a query */
+  u32 oldmask;         /* Mask of old.* columns referenced */
+  u32 newmask;         /* Mask of new.* columns referenced */
+  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
+  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
+  u8 disableTriggers;  /* True to disable triggers */
 
   /* Above is constant between recursions.  Below is reset before and after
   ** each recursion */
 
-  int nVar;            /* Number of '?' variables seen in the SQL so far */
-  int nVarExpr;        /* Number of used slots in apVarExpr[] */
-  int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */
-  Expr **apVarExpr;    /* Pointers to :aaa and $aaaa wildcard expressions */
-  int nAlias;          /* Number of aliased result set columns */
-  int nAliasAlloc;     /* Number of allocated slots for aAlias[] */
-  int *aAlias;         /* Register used to hold aliased result */
-  u8 explain;          /* True if the EXPLAIN flag is found on the query */
-  Token sErrToken;     /* The token at which the error occurred */
-  Token sNameToken;    /* Token with unqualified schema object name */
-  Token sLastToken;    /* The last token parsed */
-  const char *zSql;    /* All SQL text */
-  const char *zTail;   /* All SQL text past the last semicolon parsed */
-  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
-  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
-  TriggerStack *trigStack;  /* Trigger actions being coded */
-  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
+  int nVar;                 /* Number of '?' variables seen in the SQL so far */
+  int nzVar;                /* Number of available slots in azVar[] */
+  u8 explain;               /* True if the EXPLAIN flag is found on the query */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-  Token sArg;                /* Complete text of a module argument */
-  u8 declareVtab;            /* True if inside sqlite3_declare_vtab() */
-  int nVtabLock;             /* Number of virtual tables to lock */
-  Table **apVtabLock;        /* Pointer to virtual tables needing locking */
+  u8 declareVtab;           /* True if inside sqlite3_declare_vtab() */
+  int nVtabLock;            /* Number of virtual tables to lock */
 #endif
-  int nHeight;            /* Expression tree height of current sub-select */
-  Table *pZombieTab;      /* List of Table objects to delete after code gen */
+  int nAlias;               /* Number of aliased result set columns */
+  int nHeight;              /* Expression tree height of current sub-select */
+#ifndef SQLITE_OMIT_EXPLAIN
+  int iSelectId;            /* ID of current select for EXPLAIN output */
+  int iNextSelectId;        /* Next available select ID for EXPLAIN output */
+#endif
+  char **azVar;             /* Pointers to names of parameters */
+  Vdbe *pReprepare;         /* VM being reprepared (sqlite3Reprepare()) */
+  int *aAlias;              /* Register used to hold aliased result */
+  const char *zTail;        /* All SQL text past the last semicolon parsed */
+  Table *pNewTable;         /* A table being constructed by CREATE TABLE */
+  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
+  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
+  Token sNameToken;         /* Token with unqualified schema object name */
+  Token sLastToken;         /* The last token parsed */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  Token sArg;               /* Complete text of a module argument */
+  Table **apVtabLock;       /* Pointer to virtual tables needing locking */
+#endif
+  Table *pZombieTab;        /* List of Table objects to delete after code gen */
+  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
 };
 
+/*
+** Return true if currently inside an sqlite3_declare_vtab() call.
+*/
 #ifdef SQLITE_OMIT_VIRTUALTABLE
   #define IN_DECLARE_VTAB 0
 #else
@@ -10388,12 +11308,18 @@ struct AuthContext {
 };
 
 /*
-** Bitfield flags for P2 value in OP_Insert and OP_Delete
+** Bitfield flags for P5 value in various opcodes.
 */
-#define OPFLAG_NCHANGE   1    /* Set to update db->nChange */
-#define OPFLAG_LASTROWID 2    /* Set to update db->lastRowid */
-#define OPFLAG_ISUPDATE  4    /* This OP_Insert is an sql UPDATE */
-#define OPFLAG_APPEND    8    /* This is likely to be an append */
+#define OPFLAG_NCHANGE       0x01    /* Set to update db->nChange */
+#define OPFLAG_LASTROWID     0x02    /* Set to update db->lastRowid */
+#define OPFLAG_ISUPDATE      0x04    /* This OP_Insert is an sql UPDATE */
+#define OPFLAG_APPEND        0x08    /* This is likely to be an append */
+#define OPFLAG_USESEEKRESULT 0x10    /* Try to avoid a seek in BtreeInsert() */
+#define OPFLAG_CLEARCACHE    0x20    /* Clear pseudo-table cache in OP_Column */
+#define OPFLAG_LENGTHARG     0x40    /* OP_Column only used for length() */
+#define OPFLAG_TYPEOFARG     0x80    /* OP_Column only used for typeof() */
+#define OPFLAG_BULKCSR       0x01    /* OP_Open** used to open bulk cursor */
+#define OPFLAG_P2ISREG       0x02    /* P2 to OP_Open** is a register number */
 
 /*
  * Each trigger present in the database schema is stored as an instance of
@@ -10411,14 +11337,13 @@ struct AuthContext {
  * containing the SQL statements specified as the trigger program.
  */
 struct Trigger {
-  char *name;             /* The name of the trigger                        */
+  char *zName;            /* The name of the trigger                        */
   char *table;            /* The table or view to which the trigger applies */
   u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
   u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
   Expr *pWhen;            /* The WHEN clause of the expression (may be NULL) */
   IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
                              the <column-list> is stored here */
-  Token nameToken;        /* Token containing zName. Use during parsing only */
   Schema *pSchema;        /* Schema containing the trigger */
   Schema *pTabSchema;     /* Schema containing the table */
   TriggerStep *step_list; /* Link list of trigger program steps             */
@@ -10452,7 +11377,7 @@ struct Trigger {
  * orconf    -> stores the ON CONFLICT algorithm
  * pSelect   -> If this is an INSERT INTO ... SELECT ... statement, then
  *              this stores a pointer to the SELECT statement. Otherwise NULL.
- * target    -> A token holding the name of the table to insert into.
+ * target    -> A token holding the quoted name of the table to insert into.
  * pExprList -> If this is an INSERT INTO ... VALUES ... statement, then
  *              this stores values to be inserted. Otherwise NULL.
  * pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ... 
@@ -10460,12 +11385,12 @@ struct Trigger {
  *              inserted into.
  *
  * (op == TK_DELETE)
- * target    -> A token holding the name of the table to delete from.
+ * target    -> A token holding the quoted name of the table to delete from.
  * pWhere    -> The WHERE clause of the DELETE statement if one is specified.
  *              Otherwise NULL.
  * 
  * (op == TK_UPDATE)
- * target    -> A token holding the name of the table to update rows of.
+ * target    -> A token holding the quoted name of the table to update rows of.
  * pWhere    -> The WHERE clause of the UPDATE statement if one is specified.
  *              Otherwise NULL.
  * pExprList -> A list of the columns to update and the expressions to update
@@ -10474,60 +11399,18 @@ struct Trigger {
  * 
  */
 struct TriggerStep {
-  int op;              /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
-  int orconf;          /* OE_Rollback etc. */
+  u8 op;               /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
+  u8 orconf;           /* OE_Rollback etc. */
   Trigger *pTrig;      /* The trigger that this step is a part of */
-
-  Select *pSelect;     /* Valid for SELECT and sometimes 
-                          INSERT steps (when pExprList == 0) */
-  Token target;        /* Valid for DELETE, UPDATE, INSERT steps */
-  Expr *pWhere;        /* Valid for DELETE, UPDATE steps */
-  ExprList *pExprList; /* Valid for UPDATE statements and sometimes 
-                           INSERT steps (when pSelect == 0)         */
-  IdList *pIdList;     /* Valid for INSERT statements only */
+  Select *pSelect;     /* SELECT statment or RHS of INSERT INTO .. SELECT ... */
+  Token target;        /* Target table for DELETE, UPDATE, INSERT */
+  Expr *pWhere;        /* The WHERE clause for DELETE or UPDATE steps */
+  ExprList *pExprList; /* SET clause for UPDATE.  VALUES clause for INSERT */
+  IdList *pIdList;     /* Column names for INSERT */
   TriggerStep *pNext;  /* Next in the link-list */
   TriggerStep *pLast;  /* Last element in link-list. Valid for 1st elem only */
 };
 
-/*
- * An instance of struct TriggerStack stores information required during code
- * generation of a single trigger program. While the trigger program is being
- * coded, its associated TriggerStack instance is pointed to by the
- * "pTriggerStack" member of the Parse structure.
- *
- * The pTab member points to the table that triggers are being coded on. The 
- * newIdx member contains the index of the vdbe cursor that points at the temp
- * table that stores the new.* references. If new.* references are not valid
- * for the trigger being coded (for example an ON DELETE trigger), then newIdx
- * is set to -1. The oldIdx member is analogous to newIdx, for old.* references.
- *
- * The ON CONFLICT policy to be used for the trigger program steps is stored 
- * as the orconf member. If this is OE_Default, then the ON CONFLICT clause 
- * specified for individual triggers steps is used.
- *
- * struct TriggerStack has a "pNext" member, to allow linked lists to be
- * constructed. When coding nested triggers (triggers fired by other triggers)
- * each nested trigger stores its parent trigger's TriggerStack as the "pNext" 
- * pointer. Once the nested trigger has been coded, the pNext value is restored
- * to the pTriggerStack member of the Parse stucture and coding of the parent
- * trigger continues.
- *
- * Before a nested trigger is coded, the linked list pointed to by the 
- * pTriggerStack is scanned to ensure that the trigger is not about to be coded
- * recursively. If this condition is detected, the nested trigger is not coded.
- */
-struct TriggerStack {
-  Table *pTab;         /* Table that triggers are currently being coded on */
-  int newIdx;          /* Index of vdbe cursor to "new" temp table */
-  int oldIdx;          /* Index of vdbe cursor to "old" temp table */
-  u32 newColMask;
-  u32 oldColMask;
-  int orconf;          /* Current orconf policy */
-  int ignoreJump;      /* where to jump to for a RAISE(IGNORE) */
-  Trigger *pTrigger;   /* The trigger currently being coded */
-  TriggerStack *pNext; /* Next trigger down on the trigger stack */
-};
-
 /*
 ** The following structure contains information used by the sqliteFix...
 ** routines as they walk the parse tree to make database references
@@ -10553,7 +11436,7 @@ struct StrAccum {
   int  nAlloc;         /* Amount of space allocated in zText */
   int  mxAlloc;        /* Maximum allowed string length */
   u8   mallocFailed;   /* Becomes true if any memory allocation fails */
-  u8   useMalloc;      /* True if zText is enlargeable using realloc */
+  u8   useMalloc;      /* 0: none,  1: sqlite3DbMalloc,  2: sqlite3_malloc */
   u8   tooBig;         /* Becomes true if string size exceeds limits */
 };
 
@@ -10563,8 +11446,8 @@ struct StrAccum {
 */
 typedef struct {
   sqlite3 *db;        /* The database being initialized */
-  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
   char **pzErrMsg;    /* Error message stored here */
+  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
   int rc;             /* Result code stored here */
 } InitData;
 
@@ -10577,12 +11460,13 @@ struct Sqlite3Config {
   int bMemstat;                     /* True to enable memory status */
   int bCoreMutex;                   /* True to enable core mutexing */
   int bFullMutex;                   /* True to enable full mutexing */
+  int bOpenUri;                     /* True to interpret filenames as URIs */
   int mxStrlen;                     /* Maximum string length */
   int szLookaside;                  /* Default lookaside buffer size */
   int nLookaside;                   /* Default lookaside buffer count */
   sqlite3_mem_methods m;            /* Low-level memory allocation interface */
   sqlite3_mutex_methods mutex;      /* Low-level mutex interface */
-  sqlite3_pcache_methods pcache;    /* Low-level page-cache interface */
+  sqlite3_pcache_methods2 pcache2;  /* Low-level page-cache interface */
   void *pHeap;                      /* Heap storage space */
   int nHeap;                        /* Size of pHeap[] */
   int mnReq, mxReq;                 /* Min and max heap requests sizes */
@@ -10598,9 +11482,14 @@ struct Sqlite3Config {
   ** initially be zero, however. */
   int isInit;                       /* True after initialization has finished */
   int inProgress;                   /* True while initialization in progress */
+  int isMutexInit;                  /* True after mutexes are initialized */
   int isMallocInit;                 /* True after malloc is initialized */
+  int isPCacheInit;                 /* True after malloc is initialized */
   sqlite3_mutex *pInitMutex;        /* Mutex used by sqlite3_initialize() */
   int nRefInitMutex;                /* Number of users of pInitMutex */
+  void (*xLog)(void*,int,const char*); /* Function for logging */
+  void *pLogArg;                       /* First argument to xLog() */
+  int bLocaltimeFault;              /* True to fail localtime() calls */
 };
 
 /*
@@ -10610,9 +11499,12 @@ struct Walker {
   int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */
   int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */
   Parse *pParse;                            /* Parser context.  */
+  int walkerDepth;                          /* Number of subqueries */
   union {                                   /* Extra data for callback */
     NameContext *pNC;                          /* Naming context */
     int i;                                     /* Integer value */
+    SrcList *pSrcList;                         /* FROM clause */
+    struct SrcCount *pSrcCount;                /* Counting column references */
   } u;
 };
 
@@ -10642,26 +11534,67 @@ SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker*, Select*);
 }
 
 /*
-** The SQLITE_CORRUPT_BKPT macro can be either a constant (for production
-** builds) or a function call (for debugging).  If it is a function call,
-** it allows the operator to set a breakpoint at the spot where database
-** corruption is first detected.
+** The SQLITE_*_BKPT macros are substitutes for the error codes with
+** the same name but without the _BKPT suffix.  These macros invoke
+** routines that report the line-number on which the error originated
+** using sqlite3_log().  The routines also provide a convenient place
+** to set a debugger breakpoint.
 */
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE   int sqlite3Corrupt(void);
-# define SQLITE_CORRUPT_BKPT sqlite3Corrupt()
+SQLITE_PRIVATE int sqlite3CorruptError(int);
+SQLITE_PRIVATE int sqlite3MisuseError(int);
+SQLITE_PRIVATE int sqlite3CantopenError(int);
+#define SQLITE_CORRUPT_BKPT sqlite3CorruptError(__LINE__)
+#define SQLITE_MISUSE_BKPT sqlite3MisuseError(__LINE__)
+#define SQLITE_CANTOPEN_BKPT sqlite3CantopenError(__LINE__)
+
+
+/*
+** FTS4 is really an extension for FTS3.  It is enabled using the
+** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also all
+** the SQLITE_ENABLE_FTS4 macro to serve as an alisse for SQLITE_ENABLE_FTS3.
+*/
+#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
+# define SQLITE_ENABLE_FTS3
+#endif
+
+/*
+** The ctype.h header is needed for non-ASCII systems.  It is also
+** needed by FTS3 when FTS3 is included in the amalgamation.
+*/
+#if !defined(SQLITE_ASCII) || \
+    (defined(SQLITE_ENABLE_FTS3) && defined(SQLITE_AMALGAMATION))
+# include <ctype.h>
+#endif
+
+/*
+** The following macros mimic the standard library functions toupper(),
+** isspace(), isalnum(), isdigit() and isxdigit(), respectively. The
+** sqlite versions only work for ASCII characters, regardless of locale.
+*/
+#ifdef SQLITE_ASCII
+# define sqlite3Toupper(x)  ((x)&~(sqlite3CtypeMap[(unsigned char)(x)]&0x20))
+# define sqlite3Isspace(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x01)
+# define sqlite3Isalnum(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x06)
+# define sqlite3Isalpha(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x02)
+# define sqlite3Isdigit(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x04)
+# define sqlite3Isxdigit(x)  (sqlite3CtypeMap[(unsigned char)(x)]&0x08)
+# define sqlite3Tolower(x)   (sqlite3UpperToLower[(unsigned char)(x)])
 #else
-# define SQLITE_CORRUPT_BKPT SQLITE_CORRUPT
+# define sqlite3Toupper(x)   toupper((unsigned char)(x))
+# define sqlite3Isspace(x)   isspace((unsigned char)(x))
+# define sqlite3Isalnum(x)   isalnum((unsigned char)(x))
+# define sqlite3Isalpha(x)   isalpha((unsigned char)(x))
+# define sqlite3Isdigit(x)   isdigit((unsigned char)(x))
+# define sqlite3Isxdigit(x)  isxdigit((unsigned char)(x))
+# define sqlite3Tolower(x)   tolower((unsigned char)(x))
 #endif
 
 /*
 ** Internal function prototypes
 */
-SQLITE_PRIVATE int sqlite3StrICmp(const char *, const char *);
-SQLITE_PRIVATE int sqlite3StrNICmp(const char *, const char *, int);
-SQLITE_PRIVATE int sqlite3IsNumber(const char*, int*, u8);
-SQLITE_PRIVATE int sqlite3Strlen(sqlite3*, const char*);
+#define sqlite3StrICmp sqlite3_stricmp
 SQLITE_PRIVATE int sqlite3Strlen30(const char*);
+#define sqlite3StrNICmp sqlite3_strnicmp
 
 SQLITE_PRIVATE int sqlite3MallocInit(void);
 SQLITE_PRIVATE void sqlite3MallocEnd(void);
@@ -10683,7 +11616,25 @@ SQLITE_PRIVATE void *sqlite3PageMalloc(int);
 SQLITE_PRIVATE void sqlite3PageFree(void*);
 SQLITE_PRIVATE void sqlite3MemSetDefault(void);
 SQLITE_PRIVATE void sqlite3BenignMallocHooks(void (*)(void), void (*)(void));
-SQLITE_PRIVATE int sqlite3MemoryAlarm(void (*)(void*, sqlite3_int64, int), void*, sqlite3_int64);
+SQLITE_PRIVATE int sqlite3HeapNearlyFull(void);
+
+/*
+** On systems with ample stack space and that support alloca(), make
+** use of alloca() to obtain space for large automatic objects.  By default,
+** obtain space from malloc().
+**
+** The alloca() routine never returns NULL.  This will cause code paths
+** that deal with sqlite3StackAlloc() failures to be unreachable.
+*/
+#ifdef SQLITE_USE_ALLOCA
+# define sqlite3StackAllocRaw(D,N)   alloca(N)
+# define sqlite3StackAllocZero(D,N)  memset(alloca(N), 0, N)
+# define sqlite3StackFree(D,P)       
+#else
+# define sqlite3StackAllocRaw(D,N)   sqlite3DbMallocRaw(D,N)
+# define sqlite3StackAllocZero(D,N)  sqlite3DbMallocZero(D,N)
+# define sqlite3StackFree(D,P)       sqlite3DbFree(D,P)
+#endif
 
 #ifdef SQLITE_ENABLE_MEMSYS3
 SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void);
@@ -10694,7 +11645,8 @@ SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys5(void);
 
 
 #ifndef SQLITE_MUTEX_OMIT
-SQLITE_PRIVATE   sqlite3_mutex_methods *sqlite3DefaultMutex(void);
+SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3DefaultMutex(void);
+SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3NoopMutex(void);
 SQLITE_PRIVATE   sqlite3_mutex *sqlite3MutexAlloc(int);
 SQLITE_PRIVATE   int sqlite3MutexInit(void);
 SQLITE_PRIVATE   int sqlite3MutexEnd(void);
@@ -10704,9 +11656,16 @@ SQLITE_PRIVATE int sqlite3StatusValue(int);
 SQLITE_PRIVATE void sqlite3StatusAdd(int, int);
 SQLITE_PRIVATE void sqlite3StatusSet(int, int);
 
-SQLITE_PRIVATE int sqlite3IsNaN(double);
+#ifndef SQLITE_OMIT_FLOATING_POINT
+SQLITE_PRIVATE   int sqlite3IsNaN(double);
+#else
+# define sqlite3IsNaN(X)  0
+#endif
 
 SQLITE_PRIVATE void sqlite3VXPrintf(StrAccum*, int, const char*, va_list);
+#ifndef SQLITE_OMIT_TRACE
+SQLITE_PRIVATE void sqlite3XPrintf(StrAccum*, const char*, ...);
+#endif
 SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3*,const char*, ...);
 SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
 SQLITE_PRIVATE char *sqlite3MAppendf(sqlite3*,char*,const char*,...);
@@ -10716,11 +11675,32 @@ SQLITE_PRIVATE   void sqlite3DebugPrintf(const char*, ...);
 #if defined(SQLITE_TEST)
 SQLITE_PRIVATE   void *sqlite3TestTextToPtr(const char*);
 #endif
+
+/* Output formatting for SQLITE_TESTCTRL_EXPLAIN */
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
+SQLITE_PRIVATE   void sqlite3ExplainBegin(Vdbe*);
+SQLITE_PRIVATE   void sqlite3ExplainPrintf(Vdbe*, const char*, ...);
+SQLITE_PRIVATE   void sqlite3ExplainNL(Vdbe*);
+SQLITE_PRIVATE   void sqlite3ExplainPush(Vdbe*);
+SQLITE_PRIVATE   void sqlite3ExplainPop(Vdbe*);
+SQLITE_PRIVATE   void sqlite3ExplainFinish(Vdbe*);
+SQLITE_PRIVATE   void sqlite3ExplainSelect(Vdbe*, Select*);
+SQLITE_PRIVATE   void sqlite3ExplainExpr(Vdbe*, Expr*);
+SQLITE_PRIVATE   void sqlite3ExplainExprList(Vdbe*, ExprList*);
+SQLITE_PRIVATE   const char *sqlite3VdbeExplanation(Vdbe*);
+#else
+# define sqlite3ExplainBegin(X)
+# define sqlite3ExplainSelect(A,B)
+# define sqlite3ExplainExpr(A,B)
+# define sqlite3ExplainExprList(A,B)
+# define sqlite3ExplainFinish(X)
+# define sqlite3VdbeExplanation(X) 0
+#endif
+
+
 SQLITE_PRIVATE void sqlite3SetString(char **, sqlite3*, const char*, ...);
 SQLITE_PRIVATE void sqlite3ErrorMsg(Parse*, const char*, ...);
-SQLITE_PRIVATE void sqlite3ErrorClear(Parse*);
-SQLITE_PRIVATE void sqlite3Dequote(char*);
-SQLITE_PRIVATE void sqlite3DequoteExpr(sqlite3*, Expr*);
+SQLITE_PRIVATE int sqlite3Dequote(char*);
 SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char*, int);
 SQLITE_PRIVATE int sqlite3RunParser(Parse*, const char*, char **);
 SQLITE_PRIVATE void sqlite3FinishCoding(Parse*);
@@ -10728,21 +11708,25 @@ SQLITE_PRIVATE int sqlite3GetTempReg(Parse*);
 SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse*,int);
 SQLITE_PRIVATE int sqlite3GetTempRange(Parse*,int);
 SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse*,int,int);
-SQLITE_PRIVATE Expr *sqlite3Expr(sqlite3*, int, Expr*, Expr*, const Token*);
+SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse*);
+SQLITE_PRIVATE Expr *sqlite3ExprAlloc(sqlite3*,int,const Token*,int);
+SQLITE_PRIVATE Expr *sqlite3Expr(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(sqlite3*,Expr*,Expr*,Expr*);
 SQLITE_PRIVATE Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);
-SQLITE_PRIVATE Expr *sqlite3RegisterExpr(Parse*,Token*);
 SQLITE_PRIVATE Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);
-SQLITE_PRIVATE void sqlite3ExprSpan(Expr*,Token*,Token*);
 SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);
 SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse*, Expr*);
-SQLITE_PRIVATE void sqlite3ExprClear(sqlite3*, Expr*);
 SQLITE_PRIVATE void sqlite3ExprDelete(sqlite3*, Expr*);
-SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*,Token*);
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*);
+SQLITE_PRIVATE void sqlite3ExprListSetName(Parse*,ExprList*,Token*,int);
+SQLITE_PRIVATE void sqlite3ExprListSetSpan(Parse*,ExprList*,ExprSpan*);
 SQLITE_PRIVATE void sqlite3ExprListDelete(sqlite3*, ExprList*);
 SQLITE_PRIVATE int sqlite3Init(sqlite3*, char**);
 SQLITE_PRIVATE int sqlite3InitCallback(void*, int, char**, char**);
 SQLITE_PRIVATE void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
-SQLITE_PRIVATE void sqlite3ResetInternalSchema(sqlite3*, int);
+SQLITE_PRIVATE void sqlite3ResetAllSchemasOfConnection(sqlite3*);
+SQLITE_PRIVATE void sqlite3ResetOneSchema(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3CollapseDatabaseArray(sqlite3*);
 SQLITE_PRIVATE void sqlite3BeginParse(Parse*,int);
 SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3*);
 SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse*,Select*);
@@ -10753,20 +11737,26 @@ SQLITE_PRIVATE void sqlite3AddNotNull(Parse*, int);
 SQLITE_PRIVATE void sqlite3AddPrimaryKey(Parse*, ExprList*, int, int, int);
 SQLITE_PRIVATE void sqlite3AddCheckConstraint(Parse*, Expr*);
 SQLITE_PRIVATE void sqlite3AddColumnType(Parse*,Token*);
-SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse*,Expr*);
+SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse*,ExprSpan*);
 SQLITE_PRIVATE void sqlite3AddCollateType(Parse*, Token*);
 SQLITE_PRIVATE void sqlite3EndTable(Parse*,Token*,Token*,Select*);
+SQLITE_PRIVATE int sqlite3ParseUri(const char*,const char*,unsigned int*,
+                    sqlite3_vfs**,char**,char **);
+SQLITE_PRIVATE Btree *sqlite3DbNameToBtree(sqlite3*,const char*);
+SQLITE_PRIVATE int sqlite3CodeOnce(Parse *);
 
 SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32);
 SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec*, u32);
 SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec*, u32);
-SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec*, u32);
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec*, u32, void*);
 SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec*);
+SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec*);
 SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int,int*);
 
 SQLITE_PRIVATE RowSet *sqlite3RowSetInit(sqlite3*, void*, unsigned int);
 SQLITE_PRIVATE void sqlite3RowSetClear(RowSet*);
 SQLITE_PRIVATE void sqlite3RowSetInsert(RowSet*, i64);
+SQLITE_PRIVATE int sqlite3RowSetTest(RowSet*, u8 iBatch, i64);
 SQLITE_PRIVATE int sqlite3RowSetNext(RowSet*, i64*);
 
 SQLITE_PRIVATE void sqlite3CreateView(Parse*,Token*,Token*,Token*,Select*,int,int);
@@ -10778,9 +11768,17 @@ SQLITE_PRIVATE   int sqlite3ViewGetColumnNames(Parse*,Table*);
 #endif
 
 SQLITE_PRIVATE void sqlite3DropTable(Parse*, SrcList*, int, int);
-SQLITE_PRIVATE void sqlite3DeleteTable(Table*);
+SQLITE_PRIVATE void sqlite3CodeDropTable(Parse*, Table*, int, int);
+SQLITE_PRIVATE void sqlite3DeleteTable(sqlite3*, Table*);
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+SQLITE_PRIVATE   void sqlite3AutoincrementBegin(Parse *pParse);
+SQLITE_PRIVATE   void sqlite3AutoincrementEnd(Parse *pParse);
+#else
+# define sqlite3AutoincrementBegin(X)
+# define sqlite3AutoincrementEnd(X)
+#endif
 SQLITE_PRIVATE void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
-SQLITE_PRIVATE void *sqlite3ArrayAllocate(sqlite3*,void*,int,int,int*,int*,int*);
+SQLITE_PRIVATE void *sqlite3ArrayAllocate(sqlite3*,void*,int,int*,int*);
 SQLITE_PRIVATE IdList *sqlite3IdListAppend(sqlite3*, IdList*, Token*);
 SQLITE_PRIVATE int sqlite3IdListIndex(IdList*,const char*);
 SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(sqlite3*, SrcList*, int, int);
@@ -10793,7 +11791,7 @@ SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(SrcList*);
 SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse*, SrcList*);
 SQLITE_PRIVATE void sqlite3IdListDelete(sqlite3*, IdList*);
 SQLITE_PRIVATE void sqlite3SrcListDelete(sqlite3*, SrcList*);
-SQLITE_PRIVATE void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
+SQLITE_PRIVATE Index *sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
                         Token*, int, int);
 SQLITE_PRIVATE void sqlite3DropIndex(Parse*, SrcList*, int);
 SQLITE_PRIVATE int sqlite3Select(Parse*, Select*, SelectDest*);
@@ -10808,15 +11806,19 @@ SQLITE_PRIVATE Expr *sqlite3LimitWhere(Parse *, SrcList *, Expr *, ExprList *, E
 #endif
 SQLITE_PRIVATE void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
 SQLITE_PRIVATE void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
-SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8, int);
+SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
+    Parse*,SrcList*,Expr*,ExprList**,ExprList*,u16,int);
 SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo*);
-SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, int);
+SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, u8);
+SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
 SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse*, int, int, int);
 SQLITE_PRIVATE void sqlite3ExprCodeCopy(Parse*, int, int, int);
-SQLITE_PRIVATE void sqlite3ExprClearColumnCache(Parse*, int);
+SQLITE_PRIVATE void sqlite3ExprCacheStore(Parse*, int, int, int);
+SQLITE_PRIVATE void sqlite3ExprCachePush(Parse*);
+SQLITE_PRIVATE void sqlite3ExprCachePop(Parse*, int);
+SQLITE_PRIVATE void sqlite3ExprCacheRemove(Parse*, int, int);
+SQLITE_PRIVATE void sqlite3ExprCacheClear(Parse*);
 SQLITE_PRIVATE void sqlite3ExprCacheAffinityChange(Parse*, int, int);
-SQLITE_PRIVATE void sqlite3ExprWritableRegister(Parse*,int);
-SQLITE_PRIVATE void sqlite3ExprHardCopy(Parse*,int,int);
 SQLITE_PRIVATE int sqlite3ExprCode(Parse*, Expr*, int);
 SQLITE_PRIVATE int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
 SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse*, Expr*, int);
@@ -10834,51 +11836,52 @@ SQLITE_PRIVATE void sqlite3Vacuum(Parse*);
 SQLITE_PRIVATE int sqlite3RunVacuum(char**, sqlite3*);
 SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3*, Token*);
 SQLITE_PRIVATE int sqlite3ExprCompare(Expr*, Expr*);
+SQLITE_PRIVATE int sqlite3ExprListCompare(ExprList*, ExprList*);
 SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
 SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
+SQLITE_PRIVATE int sqlite3FunctionUsesThisSrc(Expr*, SrcList*);
 SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse*);
-SQLITE_PRIVATE Expr *sqlite3CreateIdExpr(Parse *, const char*);
 SQLITE_PRIVATE void sqlite3PrngSaveState(void);
 SQLITE_PRIVATE void sqlite3PrngRestoreState(void);
 SQLITE_PRIVATE void sqlite3PrngResetState(void);
-SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3*);
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3*,int);
 SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse*, int);
+SQLITE_PRIVATE void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb);
 SQLITE_PRIVATE void sqlite3BeginTransaction(Parse*, int);
 SQLITE_PRIVATE void sqlite3CommitTransaction(Parse*);
 SQLITE_PRIVATE void sqlite3RollbackTransaction(Parse*);
 SQLITE_PRIVATE void sqlite3Savepoint(Parse*, int, Token*);
 SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *);
+SQLITE_PRIVATE void sqlite3LeaveMutexAndCloseZombie(sqlite3*);
 SQLITE_PRIVATE int sqlite3ExprIsConstant(Expr*);
 SQLITE_PRIVATE int sqlite3ExprIsConstantNotJoin(Expr*);
 SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr*);
 SQLITE_PRIVATE int sqlite3ExprIsInteger(Expr*, int*);
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr*);
+SQLITE_PRIVATE void sqlite3ExprCodeIsNullJump(Vdbe*, const Expr*, int, int);
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr*, char);
 SQLITE_PRIVATE int sqlite3IsRowid(const char*);
-SQLITE_PRIVATE void sqlite3GenerateRowDelete(Parse*, Table*, int, int, int);
+SQLITE_PRIVATE void sqlite3GenerateRowDelete(Parse*, Table*, int, int, int, Trigger *, int);
 SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int*);
 SQLITE_PRIVATE int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int);
 SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(Parse*,Table*,int,int,
-                                     int*,int,int,int,int);
+                                     int*,int,int,int,int,int*);
 SQLITE_PRIVATE void sqlite3CompleteInsertion(Parse*, Table*, int, int, int*, int, int, int);
 SQLITE_PRIVATE int sqlite3OpenTableAndIndices(Parse*, Table*, int, int);
 SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse*, int, int);
-SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3*,Expr*);
-SQLITE_PRIVATE void sqlite3TokenCopy(sqlite3*,Token*, Token*);
-SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3*,ExprList*);
-SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3*,SrcList*);
+SQLITE_PRIVATE void sqlite3MultiWrite(Parse*);
+SQLITE_PRIVATE void sqlite3MayAbort(Parse*);
+SQLITE_PRIVATE void sqlite3HaltConstraint(Parse*, int, char*, int);
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3*,Expr*,int);
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3*,ExprList*,int);
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3*,SrcList*,int);
 SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3*,IdList*);
-SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3*,Select*);
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3*,Select*,int);
 SQLITE_PRIVATE void sqlite3FuncDefInsert(FuncDefHash*, FuncDef*);
-SQLITE_PRIVATE FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,int);
+SQLITE_PRIVATE FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,u8);
 SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(sqlite3*);
 SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void);
 SQLITE_PRIVATE void sqlite3RegisterGlobalFunctions(void);
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE   int sqlite3SafetyOn(sqlite3*);
-SQLITE_PRIVATE   int sqlite3SafetyOff(sqlite3*);
-#else
-# define sqlite3SafetyOn(A) 0
-# define sqlite3SafetyOff(A) 0
-#endif
 SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3*);
 SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3*);
 SQLITE_PRIVATE void sqlite3ChangeCookie(Parse*, int);
@@ -10893,24 +11896,32 @@ SQLITE_PRIVATE   void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,
 SQLITE_PRIVATE   void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);
 SQLITE_PRIVATE   void sqlite3DropTrigger(Parse*, SrcList*, int);
 SQLITE_PRIVATE   void sqlite3DropTriggerPtr(Parse*, Trigger*);
-SQLITE_PRIVATE   int sqlite3TriggersExist(Table*, int, ExprList*);
-SQLITE_PRIVATE   int sqlite3CodeRowTrigger(Parse*, int, ExprList*, int, Table *, int, int, 
-                           int, int, u32*, u32*);
+SQLITE_PRIVATE   Trigger *sqlite3TriggersExist(Parse *, Table*, int, ExprList*, int *pMask);
+SQLITE_PRIVATE   Trigger *sqlite3TriggerList(Parse *, Table *);
+SQLITE_PRIVATE   void sqlite3CodeRowTrigger(Parse*, Trigger *, int, ExprList*, int, Table *,
+                            int, int, int);
+SQLITE_PRIVATE   void sqlite3CodeRowTriggerDirect(Parse *, Trigger *, Table *, int, int, int);
   void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
 SQLITE_PRIVATE   void sqlite3DeleteTriggerStep(sqlite3*, TriggerStep*);
 SQLITE_PRIVATE   TriggerStep *sqlite3TriggerSelectStep(sqlite3*,Select*);
 SQLITE_PRIVATE   TriggerStep *sqlite3TriggerInsertStep(sqlite3*,Token*, IdList*,
-                                        ExprList*,Select*,int);
-SQLITE_PRIVATE   TriggerStep *sqlite3TriggerUpdateStep(sqlite3*,Token*,ExprList*, Expr*, int);
+                                        ExprList*,Select*,u8);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerUpdateStep(sqlite3*,Token*,ExprList*, Expr*, u8);
 SQLITE_PRIVATE   TriggerStep *sqlite3TriggerDeleteStep(sqlite3*,Token*, Expr*);
 SQLITE_PRIVATE   void sqlite3DeleteTrigger(sqlite3*, Trigger*);
 SQLITE_PRIVATE   void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);
+SQLITE_PRIVATE   u32 sqlite3TriggerColmask(Parse*,Trigger*,ExprList*,int,int,Table*,int);
+# define sqlite3ParseToplevel(p) ((p)->pToplevel ? (p)->pToplevel : (p))
 #else
 # define sqlite3TriggersExist(B,C,D,E,F) 0
 # define sqlite3DeleteTrigger(A,B)
 # define sqlite3DropTriggerPtr(A,B)
 # define sqlite3UnlinkAndDeleteTrigger(A,B,C)
-# define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I,J,K) 0
+# define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I)
+# define sqlite3CodeRowTriggerDirect(A,B,C,D,E,F)
+# define sqlite3TriggerList(X, Y) 0
+# define sqlite3ParseToplevel(p) p
+# define sqlite3TriggerColmask(A,B,C,D,E,F,G) 0
 #endif
 
 SQLITE_PRIVATE int sqlite3JoinType(Parse*, Token*, Token*, Token*);
@@ -10921,6 +11932,7 @@ SQLITE_PRIVATE   void sqlite3AuthRead(Parse*,Expr*,Schema*,SrcList*);
 SQLITE_PRIVATE   int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);
 SQLITE_PRIVATE   void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);
 SQLITE_PRIVATE   void sqlite3AuthContextPop(AuthContext*);
+SQLITE_PRIVATE   int sqlite3AuthReadCol(Parse*, const char *, const char *, int);
 #else
 # define sqlite3AuthRead(a,b,c,d)
 # define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK
@@ -10929,20 +11941,18 @@ SQLITE_PRIVATE   void sqlite3AuthContextPop(AuthContext*);
 #endif
 SQLITE_PRIVATE void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);
 SQLITE_PRIVATE void sqlite3Detach(Parse*, Expr*);
-SQLITE_PRIVATE int sqlite3BtreeFactory(const sqlite3 *db, const char *zFilename,
-                       int omitJournal, int nCache, int flags, Btree **ppBtree);
 SQLITE_PRIVATE int sqlite3FixInit(DbFixer*, Parse*, int, const char*, const Token*);
 SQLITE_PRIVATE int sqlite3FixSrcList(DbFixer*, SrcList*);
 SQLITE_PRIVATE int sqlite3FixSelect(DbFixer*, Select*);
 SQLITE_PRIVATE int sqlite3FixExpr(DbFixer*, Expr*);
 SQLITE_PRIVATE int sqlite3FixExprList(DbFixer*, ExprList*);
 SQLITE_PRIVATE int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
-SQLITE_PRIVATE int sqlite3AtoF(const char *z, double*);
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double*, int, u8);
 SQLITE_PRIVATE int sqlite3GetInt32(const char *, int*);
-SQLITE_PRIVATE int sqlite3FitsIn64Bits(const char *, int);
+SQLITE_PRIVATE int sqlite3Atoi(const char*);
 SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *pData, int nChar);
 SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *pData, int nByte);
-SQLITE_PRIVATE int sqlite3Utf8Read(const u8*, const u8*, const u8**);
+SQLITE_PRIVATE u32 sqlite3Utf8Read(const u8*, const u8**);
 
 /*
 ** Routines to read and write variable-length integers.  These used to
@@ -10980,24 +11990,36 @@ SQLITE_PRIVATE int sqlite3VarintLen(u64 v);
 #define putVarint    sqlite3PutVarint
 
 
-SQLITE_PRIVATE void sqlite3IndexAffinityStr(Vdbe *, Index *);
+SQLITE_PRIVATE const char *sqlite3IndexAffinityStr(Vdbe *, Index *);
 SQLITE_PRIVATE void sqlite3TableAffinityStr(Vdbe *, Table *);
 SQLITE_PRIVATE char sqlite3CompareAffinity(Expr *pExpr, char aff2);
 SQLITE_PRIVATE int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity);
 SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr);
-SQLITE_PRIVATE int sqlite3Atoi64(const char*, i64*);
+SQLITE_PRIVATE int sqlite3Atoi64(const char*, i64*, int, u8);
 SQLITE_PRIVATE void sqlite3Error(sqlite3*, int, const char*,...);
 SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3*, const char *z, int n);
+SQLITE_PRIVATE u8 sqlite3HexToInt(int h);
 SQLITE_PRIVATE int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);
 SQLITE_PRIVATE const char *sqlite3ErrStr(int);
 SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse);
-SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char *,int,int);
-SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName);
+SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char*,int);
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char*zName);
 SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr);
-SQLITE_PRIVATE Expr *sqlite3ExprSetColl(Parse *pParse, Expr *, Token *);
+SQLITE_PRIVATE Expr *sqlite3ExprSetColl(Expr*, CollSeq*);
+SQLITE_PRIVATE Expr *sqlite3ExprSetCollByToken(Parse *pParse, Expr*, Token*);
 SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *, CollSeq *);
 SQLITE_PRIVATE int sqlite3CheckObjectName(Parse *, const char *);
 SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *, int);
+SQLITE_PRIVATE int sqlite3AddInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3SubInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3MulInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3AbsInt32(int);
+#ifdef SQLITE_ENABLE_8_3_NAMES
+SQLITE_PRIVATE void sqlite3FileSuffix3(const char*, char*);
+#else
+# define sqlite3FileSuffix3(X,Y)
+#endif
+SQLITE_PRIVATE u8 sqlite3GetBoolean(const char *z,int);
 
 SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value*, u8);
 SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value*, u8);
@@ -11005,54 +12027,72 @@ SQLITE_PRIVATE void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8,
                         void(*)(void*));
 SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value*);
 SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *);
-SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *, const void*, int);
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *, const void*, int, u8);
+#ifdef SQLITE_ENABLE_STAT3
+SQLITE_PRIVATE char *sqlite3Utf8to16(sqlite3 *, u8, char *, int, int *);
+#endif
 SQLITE_PRIVATE int sqlite3ValueFromExpr(sqlite3 *, Expr *, u8, u8, sqlite3_value **);
 SQLITE_PRIVATE void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);
 #ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[];
 SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[];
+SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[];
+SQLITE_PRIVATE const Token sqlite3IntTokens[];
 SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config;
 SQLITE_PRIVATE SQLITE_WSD FuncDefHash sqlite3GlobalFunctions;
+#ifndef SQLITE_OMIT_WSD
+SQLITE_PRIVATE int sqlite3PendingByte;
 #endif
-SQLITE_PRIVATE void sqlite3RootPageMoved(Db*, int, int);
+#endif
+SQLITE_PRIVATE void sqlite3RootPageMoved(sqlite3*, int, int, int);
 SQLITE_PRIVATE void sqlite3Reindex(Parse*, Token*, Token*);
-SQLITE_PRIVATE void sqlite3AlterFunctions(sqlite3*);
+SQLITE_PRIVATE void sqlite3AlterFunctions(void);
 SQLITE_PRIVATE void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
 SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *, int *);
 SQLITE_PRIVATE void sqlite3NestedParse(Parse*, const char*, ...);
 SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3*);
-SQLITE_PRIVATE void sqlite3CodeSubselect(Parse *, Expr *, int, int);
+SQLITE_PRIVATE int sqlite3CodeSubselect(Parse *, Expr *, int, int);
 SQLITE_PRIVATE void sqlite3SelectPrep(Parse*, Select*, NameContext*);
 SQLITE_PRIVATE int sqlite3ResolveExprNames(NameContext*, Expr*);
 SQLITE_PRIVATE void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);
 SQLITE_PRIVATE int sqlite3ResolveOrderGroupBy(Parse*, Select*, ExprList*, const char*);
-SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *, Table *, int);
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *, Table *, int, int);
 SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *, Token *);
 SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
-SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(sqlite3*, CollSeq *, const char *, int);
-SQLITE_PRIVATE char sqlite3AffinityType(const Token*);
+SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(sqlite3*, u8, CollSeq *, const char*);
+SQLITE_PRIVATE char sqlite3AffinityType(const char*);
 SQLITE_PRIVATE void sqlite3Analyze(Parse*, Token*, Token*);
 SQLITE_PRIVATE int sqlite3InvokeBusyHandler(BusyHandler*);
 SQLITE_PRIVATE int sqlite3FindDb(sqlite3*, Token*);
+SQLITE_PRIVATE int sqlite3FindDbName(sqlite3 *, const char *);
 SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3*,int iDB);
+SQLITE_PRIVATE void sqlite3DeleteIndexSamples(sqlite3*,Index*);
 SQLITE_PRIVATE void sqlite3DefaultRowEst(Index*);
 SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3*, int);
 SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
 SQLITE_PRIVATE void sqlite3MinimumFileFormat(Parse*, int, int);
-SQLITE_PRIVATE void sqlite3SchemaFree(void *);
+SQLITE_PRIVATE void sqlite3SchemaClear(void *);
 SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
 SQLITE_PRIVATE int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
 SQLITE_PRIVATE KeyInfo *sqlite3IndexKeyinfo(Parse *, Index *);
 SQLITE_PRIVATE int sqlite3CreateFunc(sqlite3 *, const char *, int, int, void *, 
   void (*)(sqlite3_context*,int,sqlite3_value **),
-  void (*)(sqlite3_context*,int,sqlite3_value **), void (*)(sqlite3_context*));
+  void (*)(sqlite3_context*,int,sqlite3_value **), void (*)(sqlite3_context*),
+  FuncDestructor *pDestructor
+);
 SQLITE_PRIVATE int sqlite3ApiExit(sqlite3 *db, int);
 SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *);
 
 SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum*, char*, int, int);
 SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum*,const char*,int);
+SQLITE_PRIVATE void sqlite3AppendSpace(StrAccum*,int);
 SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum*);
 SQLITE_PRIVATE void sqlite3StrAccumReset(StrAccum*);
 SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest*,int,int);
+SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *, SrcList *, int, int);
+
+SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *);
+SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *, Pgno, const u8 *);
 
 /*
 ** The interface to the LEMON-generated parser
@@ -11064,7 +12104,7 @@ SQLITE_PRIVATE void sqlite3Parser(void*, int, Token, Parse*);
 SQLITE_PRIVATE   int sqlite3ParserStackPeak(void*);
 #endif
 
-SQLITE_PRIVATE int sqlite3AutoLoadExtensions(sqlite3*);
+SQLITE_PRIVATE void sqlite3AutoLoadExtensions(sqlite3*);
 #ifndef SQLITE_OMIT_LOAD_EXTENSION
 SQLITE_PRIVATE   void sqlite3CloseExtensions(sqlite3*);
 #else
@@ -11082,35 +12122,76 @@ SQLITE_PRIVATE   int sqlite3Utf8To8(unsigned char*);
 #endif
 
 #ifdef SQLITE_OMIT_VIRTUALTABLE
-#  define sqlite3VtabClear(X)
+#  define sqlite3VtabClear(Y)
 #  define sqlite3VtabSync(X,Y) SQLITE_OK
 #  define sqlite3VtabRollback(X)
 #  define sqlite3VtabCommit(X)
 #  define sqlite3VtabInSync(db) 0
+#  define sqlite3VtabLock(X) 
+#  define sqlite3VtabUnlock(X)
+#  define sqlite3VtabUnlockList(X)
+#  define sqlite3VtabSavepoint(X, Y, Z) SQLITE_OK
+#  define sqlite3GetVTable(X,Y)  ((VTable*)0)
 #else
-SQLITE_PRIVATE    void sqlite3VtabClear(Table*);
+SQLITE_PRIVATE    void sqlite3VtabClear(sqlite3 *db, Table*);
+SQLITE_PRIVATE    void sqlite3VtabDisconnect(sqlite3 *db, Table *p);
 SQLITE_PRIVATE    int sqlite3VtabSync(sqlite3 *db, char **);
 SQLITE_PRIVATE    int sqlite3VtabRollback(sqlite3 *db);
 SQLITE_PRIVATE    int sqlite3VtabCommit(sqlite3 *db);
+SQLITE_PRIVATE    void sqlite3VtabLock(VTable *);
+SQLITE_PRIVATE    void sqlite3VtabUnlock(VTable *);
+SQLITE_PRIVATE    void sqlite3VtabUnlockList(sqlite3*);
+SQLITE_PRIVATE    int sqlite3VtabSavepoint(sqlite3 *, int, int);
+SQLITE_PRIVATE    VTable *sqlite3GetVTable(sqlite3*, Table*);
 #  define sqlite3VtabInSync(db) ((db)->nVTrans>0 && (db)->aVTrans==0)
 #endif
 SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse*,Table*);
-SQLITE_PRIVATE void sqlite3VtabLock(sqlite3_vtab*);
-SQLITE_PRIVATE void sqlite3VtabUnlock(sqlite3*, sqlite3_vtab*);
-SQLITE_PRIVATE void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*, int);
 SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse*, Token*);
 SQLITE_PRIVATE void sqlite3VtabArgInit(Parse*);
 SQLITE_PRIVATE void sqlite3VtabArgExtend(Parse*, Token*);
 SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);
 SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse*, Table*);
 SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
-SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *, sqlite3_vtab *);
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *, VTable *);
 SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
 SQLITE_PRIVATE void sqlite3InvalidFunction(sqlite3_context*,int,sqlite3_value**);
+SQLITE_PRIVATE int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
 SQLITE_PRIVATE int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
 SQLITE_PRIVATE int sqlite3Reprepare(Vdbe*);
 SQLITE_PRIVATE void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
 SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
+SQLITE_PRIVATE int sqlite3TempInMemory(const sqlite3*);
+SQLITE_PRIVATE const char *sqlite3JournalModename(int);
+SQLITE_PRIVATE int sqlite3Checkpoint(sqlite3*, int, int, int*, int*);
+SQLITE_PRIVATE int sqlite3WalDefaultHook(void*,sqlite3*,const char*,int);
+
+/* Declarations for functions in fkey.c. All of these are replaced by
+** no-op macros if OMIT_FOREIGN_KEY is defined. In this case no foreign
+** key functionality is available. If OMIT_TRIGGER is defined but
+** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
+** this case foreign keys are parsed, but no other functionality is 
+** provided (enforcement of FK constraints requires the triggers sub-system).
+*/
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE   void sqlite3FkCheck(Parse*, Table*, int, int);
+SQLITE_PRIVATE   void sqlite3FkDropTable(Parse*, SrcList *, Table*);
+SQLITE_PRIVATE   void sqlite3FkActions(Parse*, Table*, ExprList*, int);
+SQLITE_PRIVATE   int sqlite3FkRequired(Parse*, Table*, int*, int);
+SQLITE_PRIVATE   u32 sqlite3FkOldmask(Parse*, Table*);
+SQLITE_PRIVATE   FKey *sqlite3FkReferences(Table *);
+#else
+  #define sqlite3FkActions(a,b,c,d)
+  #define sqlite3FkCheck(a,b,c,d)
+  #define sqlite3FkDropTable(a,b,c)
+  #define sqlite3FkOldmask(a,b)      0
+  #define sqlite3FkRequired(a,b,c,d) 0
+#endif
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE   void sqlite3FkDelete(sqlite3 *, Table*);
+#else
+  #define sqlite3FkDelete(a,b)
+#endif
 
 
 /*
@@ -11162,8 +12243,14 @@ SQLITE_PRIVATE   int sqlite3ExprCheckHeight(Parse*, int);
 SQLITE_PRIVATE u32 sqlite3Get4byte(const u8*);
 SQLITE_PRIVATE void sqlite3Put4byte(u8*, u32);
 
-#ifdef SQLITE_SSE
-#include "sseInt.h"
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+SQLITE_PRIVATE   void sqlite3ConnectionBlocked(sqlite3 *, sqlite3 *);
+SQLITE_PRIVATE   void sqlite3ConnectionUnlocked(sqlite3 *db);
+SQLITE_PRIVATE   void sqlite3ConnectionClosed(sqlite3 *db);
+#else
+  #define sqlite3ConnectionBlocked(x,y)
+  #define sqlite3ConnectionUnlocked(x)
+  #define sqlite3ConnectionClosed(x)
 #endif
 
 #ifdef SQLITE_DEBUG
@@ -11184,7 +12271,50 @@ SQLITE_PRIVATE void (*sqlite3IoTrace)(const char*,...);
 # define sqlite3VdbeIOTraceSql(X)
 #endif
 
+/*
+** These routines are available for the mem2.c debugging memory allocator
+** only.  They are used to verify that different "types" of memory
+** allocations are properly tracked by the system.
+**
+** sqlite3MemdebugSetType() sets the "type" of an allocation to one of
+** the MEMTYPE_* macros defined below.  The type must be a bitmask with
+** a single bit set.
+**
+** sqlite3MemdebugHasType() returns true if any of the bits in its second
+** argument match the type set by the previous sqlite3MemdebugSetType().
+** sqlite3MemdebugHasType() is intended for use inside assert() statements.
+**
+** sqlite3MemdebugNoType() returns true if none of the bits in its second
+** argument match the type set by the previous sqlite3MemdebugSetType().
+**
+** Perhaps the most important point is the difference between MEMTYPE_HEAP
+** and MEMTYPE_LOOKASIDE.  If an allocation is MEMTYPE_LOOKASIDE, that means
+** it might have been allocated by lookaside, except the allocation was
+** too large or lookaside was already full.  It is important to verify
+** that allocations that might have been satisfied by lookaside are not
+** passed back to non-lookaside free() routines.  Asserts such as the
+** example above are placed on the non-lookaside free() routines to verify
+** this constraint. 
+**
+** All of this is no-op for a production build.  It only comes into
+** play when the SQLITE_MEMDEBUG compile-time option is used.
+*/
+#ifdef SQLITE_MEMDEBUG
+SQLITE_PRIVATE   void sqlite3MemdebugSetType(void*,u8);
+SQLITE_PRIVATE   int sqlite3MemdebugHasType(void*,u8);
+SQLITE_PRIVATE   int sqlite3MemdebugNoType(void*,u8);
+#else
+# define sqlite3MemdebugSetType(X,Y)  /* no-op */
+# define sqlite3MemdebugHasType(X,Y)  1
+# define sqlite3MemdebugNoType(X,Y)   1
 #endif
+#define MEMTYPE_HEAP       0x01  /* General heap allocations */
+#define MEMTYPE_LOOKASIDE  0x02  /* Might have been lookaside memory */
+#define MEMTYPE_SCRATCH    0x04  /* Scratch allocations */
+#define MEMTYPE_PCACHE     0x08  /* Page cache allocations */
+#define MEMTYPE_DB         0x10  /* Uses sqlite3DbMalloc, not sqlite_malloc */
+
+#endif /* _SQLITEINT_H_ */
 
 /************** End of sqliteInt.h *******************************************/
 /************** Begin file global.c ******************************************/
@@ -11201,11 +12331,8 @@ SQLITE_PRIVATE void (*sqlite3IoTrace)(const char*,...);
 *************************************************************************
 **
 ** This file contains definitions of global variables and contants.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
-
 /* An array to map all upper-case characters into their corresponding
 ** lower-case character. 
 **
@@ -11251,6 +12378,80 @@ SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[] = {
 #endif
 };
 
+/*
+** The following 256 byte lookup table is used to support SQLites built-in
+** equivalents to the following standard library functions:
+**
+**   isspace()                        0x01
+**   isalpha()                        0x02
+**   isdigit()                        0x04
+**   isalnum()                        0x06
+**   isxdigit()                       0x08
+**   toupper()                        0x20
+**   SQLite identifier character      0x40
+**
+** Bit 0x20 is set if the mapped character requires translation to upper
+** case. i.e. if the character is a lower-case ASCII character.
+** If x is a lower-case ASCII character, then its upper-case equivalent
+** is (x - 0x20). Therefore toupper() can be implemented as:
+**
+**   (x & ~(map[x]&0x20))
+**
+** Standard function tolower() is implemented using the sqlite3UpperToLower[]
+** array. tolower() is used more often than toupper() by SQLite.
+**
+** Bit 0x40 is set if the character non-alphanumeric and can be used in an 
+** SQLite identifier.  Identifiers are alphanumerics, "_", "$", and any
+** non-ASCII UTF character. Hence the test for whether or not a character is
+** part of an identifier is 0x46.
+**
+** SQLite's versions are identical to the standard versions assuming a
+** locale of "C". They are implemented as macros in sqliteInt.h.
+*/
+#ifdef SQLITE_ASCII
+SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[256] = {
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 00..07    ........ */
+  0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00,  /* 08..0f    ........ */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 10..17    ........ */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 18..1f    ........ */
+  0x01, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00,  /* 20..27     !"#$%&' */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 28..2f    ()*+,-./ */
+  0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,  /* 30..37    01234567 */
+  0x0c, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 38..3f    89:;<=>? */
+
+  0x00, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x02,  /* 40..47    @ABCDEFG */
+  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 48..4f    HIJKLMNO */
+  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 50..57    PQRSTUVW */
+  0x02, 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x40,  /* 58..5f    XYZ[\]^_ */
+  0x00, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x22,  /* 60..67    `abcdefg */
+  0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 68..6f    hijklmno */
+  0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 70..77    pqrstuvw */
+  0x22, 0x22, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 78..7f    xyz{|}~. */
+
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 80..87    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 88..8f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 90..97    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 98..9f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a0..a7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a8..af    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b0..b7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b8..bf    ........ */
+
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c0..c7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c8..cf    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d0..d7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d8..df    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e0..e7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e8..ef    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* f0..f7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40   /* f8..ff    ........ */
+};
+#endif
+
+#ifndef SQLITE_USE_URI
+# define  SQLITE_USE_URI 0
+#endif
+
 /*
 ** The following singleton contains the global configuration for
 ** the SQLite library.
@@ -11259,12 +12460,13 @@ SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config = {
    SQLITE_DEFAULT_MEMSTATUS,  /* bMemstat */
    1,                         /* bCoreMutex */
    SQLITE_THREADSAFE==1,      /* bFullMutex */
+   SQLITE_USE_URI,            /* bOpenUri */
    0x7ffffffe,                /* mxStrlen */
-   100,                       /* szLookaside */
+   128,                       /* szLookaside */
    500,                       /* nLookaside */
    {0,0,0,0,0,0,0,0},         /* m */
    {0,0,0,0,0,0,0,0,0},       /* mutex */
-   {0,0,0,0,0,0,0,0,0,0,0},   /* pcache */
+   {0,0,0,0,0,0,0,0,0,0,0,0,0},/* pcache2 */
    (void*)0,                  /* pHeap */
    0,                         /* nHeap */
    0, 0,                      /* mnHeap, mxHeap */
@@ -11276,12 +12478,17 @@ SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config = {
    0,                         /* nPage */
    0,                         /* mxParserStack */
    0,                         /* sharedCacheEnabled */
-   /* All the rest need to always be zero */
+   /* All the rest should always be initialized to zero */
    0,                         /* isInit */
    0,                         /* inProgress */
+   0,                         /* isMutexInit */
    0,                         /* isMallocInit */
+   0,                         /* isPCacheInit */
    0,                         /* pInitMutex */
    0,                         /* nRefInitMutex */
+   0,                         /* xLog */
+   0,                         /* pLogArg */
+   0,                         /* bLocaltimeFault */
 };
 
 
@@ -11292,7 +12499,450 @@ SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config = {
 */
 SQLITE_PRIVATE SQLITE_WSD FuncDefHash sqlite3GlobalFunctions;
 
+/*
+** Constant tokens for values 0 and 1.
+*/
+SQLITE_PRIVATE const Token sqlite3IntTokens[] = {
+   { "0", 1 },
+   { "1", 1 }
+};
+
+
+/*
+** The value of the "pending" byte must be 0x40000000 (1 byte past the
+** 1-gibabyte boundary) in a compatible database.  SQLite never uses
+** the database page that contains the pending byte.  It never attempts
+** to read or write that page.  The pending byte page is set assign
+** for use by the VFS layers as space for managing file locks.
+**
+** During testing, it is often desirable to move the pending byte to
+** a different position in the file.  This allows code that has to
+** deal with the pending byte to run on files that are much smaller
+** than 1 GiB.  The sqlite3_test_control() interface can be used to
+** move the pending byte.
+**
+** IMPORTANT:  Changing the pending byte to any value other than
+** 0x40000000 results in an incompatible database file format!
+** Changing the pending byte during operating results in undefined
+** and dileterious behavior.
+*/
+#ifndef SQLITE_OMIT_WSD
+SQLITE_PRIVATE int sqlite3PendingByte = 0x40000000;
+#endif
+
+/*
+** Properties of opcodes.  The OPFLG_INITIALIZER macro is
+** created by mkopcodeh.awk during compilation.  Data is obtained
+** from the comments following the "case OP_xxxx:" statements in
+** the vdbe.c file.  
+*/
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[] = OPFLG_INITIALIZER;
+
 /************** End of global.c **********************************************/
+/************** Begin file ctime.c *******************************************/
+/*
+** 2010 February 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements routines used to report what compile-time options
+** SQLite was built with.
+*/
+
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+
+
+/*
+** An array of names of all compile-time options.  This array should 
+** be sorted A-Z.
+**
+** This array looks large, but in a typical installation actually uses
+** only a handful of compile-time options, so most times this array is usually
+** rather short and uses little memory space.
+*/
+static const char * const azCompileOpt[] = {
+
+/* These macros are provided to "stringify" the value of the define
+** for those options in which the value is meaningful. */
+#define CTIMEOPT_VAL_(opt) #opt
+#define CTIMEOPT_VAL(opt) CTIMEOPT_VAL_(opt)
+
+#ifdef SQLITE_32BIT_ROWID
+  "32BIT_ROWID",
+#endif
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+  "4_BYTE_ALIGNED_MALLOC",
+#endif
+#ifdef SQLITE_CASE_SENSITIVE_LIKE
+  "CASE_SENSITIVE_LIKE",
+#endif
+#ifdef SQLITE_CHECK_PAGES
+  "CHECK_PAGES",
+#endif
+#ifdef SQLITE_COVERAGE_TEST
+  "COVERAGE_TEST",
+#endif
+#ifdef SQLITE_CURDIR
+  "CURDIR",
+#endif
+#ifdef SQLITE_DEBUG
+  "DEBUG",
+#endif
+#ifdef SQLITE_DEFAULT_LOCKING_MODE
+  "DEFAULT_LOCKING_MODE=" CTIMEOPT_VAL(SQLITE_DEFAULT_LOCKING_MODE),
+#endif
+#ifdef SQLITE_DISABLE_DIRSYNC
+  "DISABLE_DIRSYNC",
+#endif
+#ifdef SQLITE_DISABLE_LFS
+  "DISABLE_LFS",
+#endif
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+  "ENABLE_ATOMIC_WRITE",
+#endif
+#ifdef SQLITE_ENABLE_CEROD
+  "ENABLE_CEROD",
+#endif
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  "ENABLE_COLUMN_METADATA",
+#endif
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  "ENABLE_EXPENSIVE_ASSERT",
+#endif
+#ifdef SQLITE_ENABLE_FTS1
+  "ENABLE_FTS1",
+#endif
+#ifdef SQLITE_ENABLE_FTS2
+  "ENABLE_FTS2",
+#endif
+#ifdef SQLITE_ENABLE_FTS3
+  "ENABLE_FTS3",
+#endif
+#ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
+  "ENABLE_FTS3_PARENTHESIS",
+#endif
+#ifdef SQLITE_ENABLE_FTS4
+  "ENABLE_FTS4",
+#endif
+#ifdef SQLITE_ENABLE_ICU
+  "ENABLE_ICU",
+#endif
+#ifdef SQLITE_ENABLE_IOTRACE
+  "ENABLE_IOTRACE",
+#endif
+#ifdef SQLITE_ENABLE_LOAD_EXTENSION
+  "ENABLE_LOAD_EXTENSION",
+#endif
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+  "ENABLE_LOCKING_STYLE=" CTIMEOPT_VAL(SQLITE_ENABLE_LOCKING_STYLE),
+#endif
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  "ENABLE_MEMORY_MANAGEMENT",
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS3
+  "ENABLE_MEMSYS3",
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS5
+  "ENABLE_MEMSYS5",
+#endif
+#ifdef SQLITE_ENABLE_OVERSIZE_CELL_CHECK
+  "ENABLE_OVERSIZE_CELL_CHECK",
+#endif
+#ifdef SQLITE_ENABLE_RTREE
+  "ENABLE_RTREE",
+#endif
+#ifdef SQLITE_ENABLE_STAT3
+  "ENABLE_STAT3",
+#endif
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  "ENABLE_UNLOCK_NOTIFY",
+#endif
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  "ENABLE_UPDATE_DELETE_LIMIT",
+#endif
+#ifdef SQLITE_HAS_CODEC
+  "HAS_CODEC",
+#endif
+#ifdef SQLITE_HAVE_ISNAN
+  "HAVE_ISNAN",
+#endif
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  "HOMEGROWN_RECURSIVE_MUTEX",
+#endif
+#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
+  "IGNORE_AFP_LOCK_ERRORS",
+#endif
+#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
+  "IGNORE_FLOCK_LOCK_ERRORS",
+#endif
+#ifdef SQLITE_INT64_TYPE
+  "INT64_TYPE",
+#endif
+#ifdef SQLITE_LOCK_TRACE
+  "LOCK_TRACE",
+#endif
+#ifdef SQLITE_MAX_SCHEMA_RETRY
+  "MAX_SCHEMA_RETRY=" CTIMEOPT_VAL(SQLITE_MAX_SCHEMA_RETRY),
+#endif
+#ifdef SQLITE_MEMDEBUG
+  "MEMDEBUG",
+#endif
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+  "MIXED_ENDIAN_64BIT_FLOAT",
+#endif
+#ifdef SQLITE_NO_SYNC
+  "NO_SYNC",
+#endif
+#ifdef SQLITE_OMIT_ALTERTABLE
+  "OMIT_ALTERTABLE",
+#endif
+#ifdef SQLITE_OMIT_ANALYZE
+  "OMIT_ANALYZE",
+#endif
+#ifdef SQLITE_OMIT_ATTACH
+  "OMIT_ATTACH",
+#endif
+#ifdef SQLITE_OMIT_AUTHORIZATION
+  "OMIT_AUTHORIZATION",
+#endif
+#ifdef SQLITE_OMIT_AUTOINCREMENT
+  "OMIT_AUTOINCREMENT",
+#endif
+#ifdef SQLITE_OMIT_AUTOINIT
+  "OMIT_AUTOINIT",
+#endif
+#ifdef SQLITE_OMIT_AUTOMATIC_INDEX
+  "OMIT_AUTOMATIC_INDEX",
+#endif
+#ifdef SQLITE_OMIT_AUTORESET
+  "OMIT_AUTORESET",
+#endif
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  "OMIT_AUTOVACUUM",
+#endif
+#ifdef SQLITE_OMIT_BETWEEN_OPTIMIZATION
+  "OMIT_BETWEEN_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_BLOB_LITERAL
+  "OMIT_BLOB_LITERAL",
+#endif
+#ifdef SQLITE_OMIT_BTREECOUNT
+  "OMIT_BTREECOUNT",
+#endif
+#ifdef SQLITE_OMIT_BUILTIN_TEST
+  "OMIT_BUILTIN_TEST",
+#endif
+#ifdef SQLITE_OMIT_CAST
+  "OMIT_CAST",
+#endif
+#ifdef SQLITE_OMIT_CHECK
+  "OMIT_CHECK",
+#endif
+/* // redundant
+** #ifdef SQLITE_OMIT_COMPILEOPTION_DIAGS
+**   "OMIT_COMPILEOPTION_DIAGS",
+** #endif
+*/
+#ifdef SQLITE_OMIT_COMPLETE
+  "OMIT_COMPLETE",
+#endif
+#ifdef SQLITE_OMIT_COMPOUND_SELECT
+  "OMIT_COMPOUND_SELECT",
+#endif
+#ifdef SQLITE_OMIT_DATETIME_FUNCS
+  "OMIT_DATETIME_FUNCS",
+#endif
+#ifdef SQLITE_OMIT_DECLTYPE
+  "OMIT_DECLTYPE",
+#endif
+#ifdef SQLITE_OMIT_DEPRECATED
+  "OMIT_DEPRECATED",
+#endif
+#ifdef SQLITE_OMIT_DISKIO
+  "OMIT_DISKIO",
+#endif
+#ifdef SQLITE_OMIT_EXPLAIN
+  "OMIT_EXPLAIN",
+#endif
+#ifdef SQLITE_OMIT_FLAG_PRAGMAS
+  "OMIT_FLAG_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_FLOATING_POINT
+  "OMIT_FLOATING_POINT",
+#endif
+#ifdef SQLITE_OMIT_FOREIGN_KEY
+  "OMIT_FOREIGN_KEY",
+#endif
+#ifdef SQLITE_OMIT_GET_TABLE
+  "OMIT_GET_TABLE",
+#endif
+#ifdef SQLITE_OMIT_INCRBLOB
+  "OMIT_INCRBLOB",
+#endif
+#ifdef SQLITE_OMIT_INTEGRITY_CHECK
+  "OMIT_INTEGRITY_CHECK",
+#endif
+#ifdef SQLITE_OMIT_LIKE_OPTIMIZATION
+  "OMIT_LIKE_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_LOAD_EXTENSION
+  "OMIT_LOAD_EXTENSION",
+#endif
+#ifdef SQLITE_OMIT_LOCALTIME
+  "OMIT_LOCALTIME",
+#endif
+#ifdef SQLITE_OMIT_LOOKASIDE
+  "OMIT_LOOKASIDE",
+#endif
+#ifdef SQLITE_OMIT_MEMORYDB
+  "OMIT_MEMORYDB",
+#endif
+#ifdef SQLITE_OMIT_MERGE_SORT
+  "OMIT_MERGE_SORT",
+#endif
+#ifdef SQLITE_OMIT_OR_OPTIMIZATION
+  "OMIT_OR_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_PAGER_PRAGMAS
+  "OMIT_PAGER_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_PRAGMA
+  "OMIT_PRAGMA",
+#endif
+#ifdef SQLITE_OMIT_PROGRESS_CALLBACK
+  "OMIT_PROGRESS_CALLBACK",
+#endif
+#ifdef SQLITE_OMIT_QUICKBALANCE
+  "OMIT_QUICKBALANCE",
+#endif
+#ifdef SQLITE_OMIT_REINDEX
+  "OMIT_REINDEX",
+#endif
+#ifdef SQLITE_OMIT_SCHEMA_PRAGMAS
+  "OMIT_SCHEMA_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
+  "OMIT_SCHEMA_VERSION_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_SHARED_CACHE
+  "OMIT_SHARED_CACHE",
+#endif
+#ifdef SQLITE_OMIT_SUBQUERY
+  "OMIT_SUBQUERY",
+#endif
+#ifdef SQLITE_OMIT_TCL_VARIABLE
+  "OMIT_TCL_VARIABLE",
+#endif
+#ifdef SQLITE_OMIT_TEMPDB
+  "OMIT_TEMPDB",
+#endif
+#ifdef SQLITE_OMIT_TRACE
+  "OMIT_TRACE",
+#endif
+#ifdef SQLITE_OMIT_TRIGGER
+  "OMIT_TRIGGER",
+#endif
+#ifdef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
+  "OMIT_TRUNCATE_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_UTF16
+  "OMIT_UTF16",
+#endif
+#ifdef SQLITE_OMIT_VACUUM
+  "OMIT_VACUUM",
+#endif
+#ifdef SQLITE_OMIT_VIEW
+  "OMIT_VIEW",
+#endif
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  "OMIT_VIRTUALTABLE",
+#endif
+#ifdef SQLITE_OMIT_WAL
+  "OMIT_WAL",
+#endif
+#ifdef SQLITE_OMIT_WSD
+  "OMIT_WSD",
+#endif
+#ifdef SQLITE_OMIT_XFER_OPT
+  "OMIT_XFER_OPT",
+#endif
+#ifdef SQLITE_PERFORMANCE_TRACE
+  "PERFORMANCE_TRACE",
+#endif
+#ifdef SQLITE_PROXY_DEBUG
+  "PROXY_DEBUG",
+#endif
+#ifdef SQLITE_SECURE_DELETE
+  "SECURE_DELETE",
+#endif
+#ifdef SQLITE_SMALL_STACK
+  "SMALL_STACK",
+#endif
+#ifdef SQLITE_SOUNDEX
+  "SOUNDEX",
+#endif
+#ifdef SQLITE_TCL
+  "TCL",
+#endif
+#ifdef SQLITE_TEMP_STORE
+  "TEMP_STORE=" CTIMEOPT_VAL(SQLITE_TEMP_STORE),
+#endif
+#ifdef SQLITE_TEST
+  "TEST",
+#endif
+#ifdef SQLITE_THREADSAFE
+  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
+#endif
+#ifdef SQLITE_USE_ALLOCA
+  "USE_ALLOCA",
+#endif
+#ifdef SQLITE_ZERO_MALLOC
+  "ZERO_MALLOC"
+#endif
+};
+
+/*
+** Given the name of a compile-time option, return true if that option
+** was used and false if not.
+**
+** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
+** is not required for a match.
+*/
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName){
+  int i, n;
+  if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
+  n = sqlite3Strlen30(zOptName);
+
+  /* Since ArraySize(azCompileOpt) is normally in single digits, a
+  ** linear search is adequate.  No need for a binary search. */
+  for(i=0; i<ArraySize(azCompileOpt); i++){
+    if(   (sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0)
+       && ( (azCompileOpt[i][n]==0) || (azCompileOpt[i][n]=='=') ) ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Return the N-th compile-time option string.  If N is out of range,
+** return a NULL pointer.
+*/
+SQLITE_API const char *sqlite3_compileoption_get(int N){
+  if( N>=0 && N<ArraySize(azCompileOpt) ){
+    return azCompileOpt[N];
+  }
+  return 0;
+}
+
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/************** End of ctime.c ***********************************************/
 /************** Begin file status.c ******************************************/
 /*
 ** 2008 June 18
@@ -11308,17 +12958,494 @@ SQLITE_PRIVATE SQLITE_WSD FuncDefHash sqlite3GlobalFunctions;
 **
 ** This module implements the sqlite3_status() interface and related
 ** functionality.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/************** Include vdbeInt.h in the middle of status.c ******************/
+/************** Begin file vdbeInt.h *****************************************/
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for information that is private to the
+** VDBE.  This information used to all be at the top of the single
+** source code file "vdbe.c".  When that file became too big (over
+** 6000 lines long) it was split up into several smaller files and
+** this header information was factored out.
+*/
+#ifndef _VDBEINT_H_
+#define _VDBEINT_H_
+
+/*
+** SQL is translated into a sequence of instructions to be
+** executed by a virtual machine.  Each instruction is an instance
+** of the following structure.
+*/
+typedef struct VdbeOp Op;
+
+/*
+** Boolean values
+*/
+typedef unsigned char Bool;
+
+/* Opaque type used by code in vdbesort.c */
+typedef struct VdbeSorter VdbeSorter;
+
+/* Opaque type used by the explainer */
+typedef struct Explain Explain;
+
+/*
+** A cursor is a pointer into a single BTree within a database file.
+** The cursor can seek to a BTree entry with a particular key, or
+** loop over all entries of the Btree.  You can also insert new BTree
+** entries or retrieve the key or data from the entry that the cursor
+** is currently pointing to.
+** 
+** Every cursor that the virtual machine has open is represented by an
+** instance of the following structure.
+*/
+struct VdbeCursor {
+  BtCursor *pCursor;    /* The cursor structure of the backend */
+  Btree *pBt;           /* Separate file holding temporary table */
+  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */
+  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */
+  int pseudoTableReg;   /* Register holding pseudotable content. */
+  int nField;           /* Number of fields in the header */
+  Bool zeroed;          /* True if zeroed out and ready for reuse */
+  Bool rowidIsValid;    /* True if lastRowid is valid */
+  Bool atFirst;         /* True if pointing to first entry */
+  Bool useRandomRowid;  /* Generate new record numbers semi-randomly */
+  Bool nullRow;         /* True if pointing to a row with no data */
+  Bool deferredMoveto;  /* A call to sqlite3BtreeMoveto() is needed */
+  Bool isTable;         /* True if a table requiring integer keys */
+  Bool isIndex;         /* True if an index containing keys only - no data */
+  Bool isOrdered;       /* True if the underlying table is BTREE_UNORDERED */
+  Bool isSorter;        /* True if a new-style sorter */
+  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
+  const sqlite3_module *pModule;     /* Module for cursor pVtabCursor */
+  i64 seqCount;         /* Sequence counter */
+  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
+  i64 lastRowid;        /* Last rowid from a Next or NextIdx operation */
+  VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */
+
+  /* Result of last sqlite3BtreeMoveto() done by an OP_NotExists or 
+  ** OP_IsUnique opcode on this cursor. */
+  int seekResult;
+
+  /* Cached information about the header for the data record that the
+  ** cursor is currently pointing to.  Only valid if cacheStatus matches
+  ** Vdbe.cacheCtr.  Vdbe.cacheCtr will never take on the value of
+  ** CACHE_STALE and so setting cacheStatus=CACHE_STALE guarantees that
+  ** the cache is out of date.
+  **
+  ** aRow might point to (ephemeral) data for the current row, or it might
+  ** be NULL.
+  */
+  u32 cacheStatus;      /* Cache is valid if this matches Vdbe.cacheCtr */
+  int payloadSize;      /* Total number of bytes in the record */
+  u32 *aType;           /* Type values for all entries in the record */
+  u32 *aOffset;         /* Cached offsets to the start of each columns data */
+  u8 *aRow;             /* Data for the current row, if all on one page */
+};
+typedef struct VdbeCursor VdbeCursor;
+
+/*
+** When a sub-program is executed (OP_Program), a structure of this type
+** is allocated to store the current value of the program counter, as
+** well as the current memory cell array and various other frame specific
+** values stored in the Vdbe struct. When the sub-program is finished, 
+** these values are copied back to the Vdbe from the VdbeFrame structure,
+** restoring the state of the VM to as it was before the sub-program
+** began executing.
+**
+** The memory for a VdbeFrame object is allocated and managed by a memory
+** cell in the parent (calling) frame. When the memory cell is deleted or
+** overwritten, the VdbeFrame object is not freed immediately. Instead, it
+** is linked into the Vdbe.pDelFrame list. The contents of the Vdbe.pDelFrame
+** list is deleted when the VM is reset in VdbeHalt(). The reason for doing
+** this instead of deleting the VdbeFrame immediately is to avoid recursive
+** calls to sqlite3VdbeMemRelease() when the memory cells belonging to the
+** child frame are released.
+**
+** The currently executing frame is stored in Vdbe.pFrame. Vdbe.pFrame is
+** set to NULL if the currently executing frame is the main program.
+*/
+typedef struct VdbeFrame VdbeFrame;
+struct VdbeFrame {
+  Vdbe *v;                /* VM this frame belongs to */
+  VdbeFrame *pParent;     /* Parent of this frame, or NULL if parent is main */
+  Op *aOp;                /* Program instructions for parent frame */
+  Mem *aMem;              /* Array of memory cells for parent frame */
+  u8 *aOnceFlag;          /* Array of OP_Once flags for parent frame */
+  VdbeCursor **apCsr;     /* Array of Vdbe cursors for parent frame */
+  void *token;            /* Copy of SubProgram.token */
+  i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
+  u16 nCursor;            /* Number of entries in apCsr */
+  int pc;                 /* Program Counter in parent (calling) frame */
+  int nOp;                /* Size of aOp array */
+  int nMem;               /* Number of entries in aMem */
+  int nOnceFlag;          /* Number of entries in aOnceFlag */
+  int nChildMem;          /* Number of memory cells for child frame */
+  int nChildCsr;          /* Number of cursors for child frame */
+  int nChange;            /* Statement changes (Vdbe.nChanges)     */
+};
+
+#define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])
+
+/*
+** A value for VdbeCursor.cacheValid that means the cache is always invalid.
+*/
+#define CACHE_STALE 0
+
+/*
+** Internally, the vdbe manipulates nearly all SQL values as Mem
+** structures. Each Mem struct may cache multiple representations (string,
+** integer etc.) of the same value.
+*/
+struct Mem {
+  sqlite3 *db;        /* The associated database connection */
+  char *z;            /* String or BLOB value */
+  double r;           /* Real value */
+  union {
+    i64 i;              /* Integer value used when MEM_Int is set in flags */
+    int nZero;          /* Used when bit MEM_Zero is set in flags */
+    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
+    RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
+    VdbeFrame *pFrame;  /* Used when flags==MEM_Frame */
+  } u;
+  int n;              /* Number of characters in string value, excluding '\0' */
+  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
+  u8  type;           /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
+  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
+#ifdef SQLITE_DEBUG
+  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
+  void *pFiller;      /* So that sizeof(Mem) is a multiple of 8 */
+#endif
+  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */
+  char *zMalloc;      /* Dynamic buffer allocated by sqlite3_malloc() */
+};
+
+/* One or more of the following flags are set to indicate the validOK
+** representations of the value stored in the Mem struct.
+**
+** If the MEM_Null flag is set, then the value is an SQL NULL value.
+** No other flags may be set in this case.
+**
+** If the MEM_Str flag is set then Mem.z points at a string representation.
+** Usually this is encoded in the same unicode encoding as the main
+** database (see below for exceptions). If the MEM_Term flag is also
+** set, then the string is nul terminated. The MEM_Int and MEM_Real 
+** flags may coexist with the MEM_Str flag.
+*/
+#define MEM_Null      0x0001   /* Value is NULL */
+#define MEM_Str       0x0002   /* Value is a string */
+#define MEM_Int       0x0004   /* Value is an integer */
+#define MEM_Real      0x0008   /* Value is a real number */
+#define MEM_Blob      0x0010   /* Value is a BLOB */
+#define MEM_RowSet    0x0020   /* Value is a RowSet object */
+#define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
+#define MEM_Invalid   0x0080   /* Value is undefined */
+#define MEM_TypeMask  0x00ff   /* Mask of type bits */
+
+/* Whenever Mem contains a valid string or blob representation, one of
+** the following flags must be set to determine the memory management
+** policy for Mem.z.  The MEM_Term flag tells us whether or not the
+** string is \000 or \u0000 terminated
+*/
+#define MEM_Term      0x0200   /* String rep is nul terminated */
+#define MEM_Dyn       0x0400   /* Need to call sqliteFree() on Mem.z */
+#define MEM_Static    0x0800   /* Mem.z points to a static string */
+#define MEM_Ephem     0x1000   /* Mem.z points to an ephemeral string */
+#define MEM_Agg       0x2000   /* Mem.z points to an agg function context */
+#define MEM_Zero      0x4000   /* Mem.i contains count of 0s appended to blob */
+#ifdef SQLITE_OMIT_INCRBLOB
+  #undef MEM_Zero
+  #define MEM_Zero 0x0000
+#endif
+
+/*
+** Clear any existing type flags from a Mem and replace them with f
+*/
+#define MemSetTypeFlag(p, f) \
+   ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f)
+
+/*
+** Return true if a memory cell is not marked as invalid.  This macro
+** is for use inside assert() statements only.
+*/
+#ifdef SQLITE_DEBUG
+#define memIsValid(M)  ((M)->flags & MEM_Invalid)==0
+#endif
+
+
+/* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
+** additional information about auxiliary information bound to arguments
+** of the function.  This is used to implement the sqlite3_get_auxdata()
+** and sqlite3_set_auxdata() APIs.  The "auxdata" is some auxiliary data
+** that can be associated with a constant argument to a function.  This
+** allows functions such as "regexp" to compile their constant regular
+** expression argument once and reused the compiled code for multiple
+** invocations.
+*/
+struct VdbeFunc {
+  FuncDef *pFunc;               /* The definition of the function */
+  int nAux;                     /* Number of entries allocated for apAux[] */
+  struct AuxData {
+    void *pAux;                   /* Aux data for the i-th argument */
+    void (*xDelete)(void *);      /* Destructor for the aux data */
+  } apAux[1];                   /* One slot for each function argument */
+};
+
+/*
+** The "context" argument for a installable function.  A pointer to an
+** instance of this structure is the first argument to the routines used
+** implement the SQL functions.
+**
+** There is a typedef for this structure in sqlite.h.  So all routines,
+** even the public interface to SQLite, can use a pointer to this structure.
+** But this file is the only place where the internal details of this
+** structure are known.
+**
+** This structure is defined inside of vdbeInt.h because it uses substructures
+** (Mem) which are only defined there.
+*/
+struct sqlite3_context {
+  FuncDef *pFunc;       /* Pointer to function information.  MUST BE FIRST */
+  VdbeFunc *pVdbeFunc;  /* Auxilary data, if created. */
+  Mem s;                /* The return value is stored here */
+  Mem *pMem;            /* Memory cell used to store aggregate context */
+  CollSeq *pColl;       /* Collating sequence */
+  int isError;          /* Error code returned by the function. */
+  int skipFlag;         /* Skip skip accumulator loading if true */
+};
+
+/*
+** An Explain object accumulates indented output which is helpful
+** in describing recursive data structures.
+*/
+struct Explain {
+  Vdbe *pVdbe;       /* Attach the explanation to this Vdbe */
+  StrAccum str;      /* The string being accumulated */
+  int nIndent;       /* Number of elements in aIndent */
+  u16 aIndent[100];  /* Levels of indentation */
+  char zBase[100];   /* Initial space */
+};
+
+/*
+** An instance of the virtual machine.  This structure contains the complete
+** state of the virtual machine.
+**
+** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare()
+** is really a pointer to an instance of this structure.
+**
+** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
+** any virtual table method invocations made by the vdbe program. It is
+** set to 2 for xDestroy method calls and 1 for all other methods. This
+** variable is used for two purposes: to allow xDestroy methods to execute
+** "DROP TABLE" statements and to prevent some nasty side effects of
+** malloc failure when SQLite is invoked recursively by a virtual table 
+** method function.
+*/
+struct Vdbe {
+  sqlite3 *db;            /* The database connection that owns this statement */
+  Op *aOp;                /* Space to hold the virtual machine's program */
+  Mem *aMem;              /* The memory locations */
+  Mem **apArg;            /* Arguments to currently executing user function */
+  Mem *aColName;          /* Column names to return */
+  Mem *pResultSet;        /* Pointer to an array of results */
+  int nMem;               /* Number of memory locations currently allocated */
+  int nOp;                /* Number of instructions in the program */
+  int nOpAlloc;           /* Number of slots allocated for aOp[] */
+  int nLabel;             /* Number of labels used */
+  int *aLabel;            /* Space to hold the labels */
+  u16 nResColumn;         /* Number of columns in one row of the result set */
+  u16 nCursor;            /* Number of slots in apCsr[] */
+  u32 magic;              /* Magic number for sanity checking */
+  char *zErrMsg;          /* Error message written here */
+  Vdbe *pPrev,*pNext;     /* Linked list of VDBEs with the same Vdbe.db */
+  VdbeCursor **apCsr;     /* One element of this array for each open cursor */
+  Mem *aVar;              /* Values for the OP_Variable opcode. */
+  char **azVar;           /* Name of variables */
+  ynVar nVar;             /* Number of entries in aVar[] */
+  ynVar nzVar;            /* Number of entries in azVar[] */
+  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
+  int pc;                 /* The program counter */
+  int rc;                 /* Value to return */
+  u8 errorAction;         /* Recovery action to do in case of an error */
+  u8 explain;             /* True if EXPLAIN present on SQL command */
+  u8 changeCntOn;         /* True to update the change-counter */
+  u8 expired;             /* True if the VM needs to be recompiled */
+  u8 runOnlyOnce;         /* Automatically expire on reset */
+  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
+  u8 inVtabMethod;        /* See comments above */
+  u8 usesStmtJournal;     /* True if uses a statement journal */
+  u8 readOnly;            /* True for read-only statements */
+  u8 isPrepareV2;         /* True if prepared with prepare_v2() */
+  int nChange;            /* Number of db changes made since last reset */
+  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
+  yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
+  int iStatement;         /* Statement number (or 0 if has not opened stmt) */
+  int aCounter[3];        /* Counters used by sqlite3_stmt_status() */
+#ifndef SQLITE_OMIT_TRACE
+  i64 startTime;          /* Time when query started - used for profiling */
+#endif
+  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
+  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
+  char *zSql;             /* Text of the SQL statement that generated this */
+  void *pFree;            /* Free this when deleting the vdbe */
+#ifdef SQLITE_DEBUG
+  FILE *trace;            /* Write an execution trace here, if not NULL */
+#endif
+#ifdef SQLITE_ENABLE_TREE_EXPLAIN
+  Explain *pExplain;      /* The explainer */
+  char *zExplain;         /* Explanation of data structures */
+#endif
+  VdbeFrame *pFrame;      /* Parent frame */
+  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */
+  int nFrame;             /* Number of frames in pFrame list */
+  u32 expmask;            /* Binding to these vars invalidates VM */
+  SubProgram *pProgram;   /* Linked list of all sub-programs used by VM */
+  int nOnceFlag;          /* Size of array aOnceFlag[] */
+  u8 *aOnceFlag;          /* Flags for OP_Once */
+};
+
+/*
+** The following are allowed values for Vdbe.magic
+*/
+#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */
+#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */
+#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */
+#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated */
+
+/*
+** Function prototypes
+*/
+SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*);
+void sqliteVdbePopStack(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeCursorMoveto(VdbeCursor*);
+#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
+SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE*, int, Op*);
+#endif
+SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32);
+SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem*, int);
+SQLITE_PRIVATE u32 sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
+SQLITE_PRIVATE u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
+SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
+
+int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
+SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*);
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(sqlite3*, BtCursor *, i64 *);
+SQLITE_PRIVATE int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
+SQLITE_PRIVATE int sqlite3VdbeExec(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeList(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *, int);
+SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem*, const Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
+SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem*, Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem*, i64);
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64
+#else
+SQLITE_PRIVATE   void sqlite3VdbeMemSetDouble(Mem*, double);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem*,int);
+SQLITE_PRIVATE void sqlite3VdbeMemSetRowSet(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem*, int);
+SQLITE_PRIVATE i64 sqlite3VdbeIntValue(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem*);
+SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
+SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
+SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p);
+#define VdbeMemRelease(X)  \
+  if((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame)) \
+    sqlite3VdbeMemReleaseExternal(X);
+SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
+SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
+SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
+SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *, int);
+SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame*);
+SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *);
+SQLITE_PRIVATE void sqlite3VdbeMemStoreType(Mem *pMem);
+SQLITE_PRIVATE int sqlite3VdbeTransferError(Vdbe *p);
+
+#ifdef SQLITE_OMIT_MERGE_SORT
+# define sqlite3VdbeSorterInit(Y,Z)      SQLITE_OK
+# define sqlite3VdbeSorterWrite(X,Y,Z)   SQLITE_OK
+# define sqlite3VdbeSorterClose(Y,Z)
+# define sqlite3VdbeSorterRowkey(Y,Z)    SQLITE_OK
+# define sqlite3VdbeSorterRewind(X,Y,Z)  SQLITE_OK
+# define sqlite3VdbeSorterNext(X,Y,Z)    SQLITE_OK
+# define sqlite3VdbeSorterCompare(X,Y,Z) SQLITE_OK
+#else
+SQLITE_PRIVATE int sqlite3VdbeSorterInit(sqlite3 *, VdbeCursor *);
+SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
+SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);
+SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *, const VdbeCursor *, int *);
+SQLITE_PRIVATE int sqlite3VdbeSorterRewind(sqlite3 *, const VdbeCursor *, int *);
+SQLITE_PRIVATE int sqlite3VdbeSorterWrite(sqlite3 *, const VdbeCursor *, Mem *);
+SQLITE_PRIVATE int sqlite3VdbeSorterCompare(const VdbeCursor *, Mem *, int *);
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
+SQLITE_PRIVATE   void sqlite3VdbeEnter(Vdbe*);
+SQLITE_PRIVATE   void sqlite3VdbeLeave(Vdbe*);
+#else
+# define sqlite3VdbeEnter(X)
+# define sqlite3VdbeLeave(X)
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE void sqlite3VdbeMemAboutToChange(Vdbe*,Mem*);
+#endif
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE int sqlite3VdbeCheckFk(Vdbe *, int);
+#else
+# define sqlite3VdbeCheckFk(p,i) 0
+#endif
+
+SQLITE_PRIVATE int sqlite3VdbeMemTranslate(Mem*, u8);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbePrintSql(Vdbe*);
+SQLITE_PRIVATE   void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem);
+
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE   int sqlite3VdbeMemExpandBlob(Mem *);
+  #define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
+#else
+  #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
+  #define ExpandBlob(P) SQLITE_OK
+#endif
+
+#endif /* !defined(_VDBEINT_H_) */
+
+/************** End of vdbeInt.h *********************************************/
+/************** Continuing where we left off in status.c *********************/
 
 /*
 ** Variables in which to record status information.
 */
 typedef struct sqlite3StatType sqlite3StatType;
 static SQLITE_WSD struct sqlite3StatType {
-  int nowValue[9];         /* Current value */
-  int mxValue[9];          /* Maximum value */
+  int nowValue[10];         /* Current value */
+  int mxValue[10];          /* Maximum value */
 } sqlite3Stat = { {0,}, {0,} };
 
 
@@ -11380,7 +13507,7 @@ SQLITE_PRIVATE void sqlite3StatusSet(int op, int X){
 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag){
   wsdStatInit;
   if( op<0 || op>=ArraySize(wsdStat.nowValue) ){
-    return SQLITE_MISUSE;
+    return SQLITE_MISUSE_BKPT;
   }
   *pCurrent = wsdStat.nowValue[op];
   *pHighwater = wsdStat.mxValue[op];
@@ -11400,6 +13527,8 @@ SQLITE_API int sqlite3_db_status(
   int *pHighwater,      /* Write high-water mark here */
   int resetFlag         /* Reset high-water mark if true */
 ){
+  int rc = SQLITE_OK;   /* Return code */
+  sqlite3_mutex_enter(db->mutex);
   switch( op ){
     case SQLITE_DBSTATUS_LOOKASIDE_USED: {
       *pCurrent = db->lookaside.nOut;
@@ -11409,11 +13538,139 @@ SQLITE_API int sqlite3_db_status(
       }
       break;
     }
+
+    case SQLITE_DBSTATUS_LOOKASIDE_HIT:
+    case SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE:
+    case SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL: {
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_HIT );
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE );
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL );
+      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)>=0 );
+      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)<3 );
+      *pCurrent = 0;
+      *pHighwater = db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT];
+      if( resetFlag ){
+        db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT] = 0;
+      }
+      break;
+    }
+
+    /* 
+    ** Return an approximation for the amount of memory currently used
+    ** by all pagers associated with the given database connection.  The
+    ** highwater mark is meaningless and is returned as zero.
+    */
+    case SQLITE_DBSTATUS_CACHE_USED: {
+      int totalUsed = 0;
+      int i;
+      sqlite3BtreeEnterAll(db);
+      for(i=0; i<db->nDb; i++){
+        Btree *pBt = db->aDb[i].pBt;
+        if( pBt ){
+          Pager *pPager = sqlite3BtreePager(pBt);
+          totalUsed += sqlite3PagerMemUsed(pPager);
+        }
+      }
+      sqlite3BtreeLeaveAll(db);
+      *pCurrent = totalUsed;
+      *pHighwater = 0;
+      break;
+    }
+
+    /*
+    ** *pCurrent gets an accurate estimate of the amount of memory used
+    ** to store the schema for all databases (main, temp, and any ATTACHed
+    ** databases.  *pHighwater is set to zero.
+    */
+    case SQLITE_DBSTATUS_SCHEMA_USED: {
+      int i;                      /* Used to iterate through schemas */
+      int nByte = 0;              /* Used to accumulate return value */
+
+      sqlite3BtreeEnterAll(db);
+      db->pnBytesFreed = &nByte;
+      for(i=0; i<db->nDb; i++){
+        Schema *pSchema = db->aDb[i].pSchema;
+        if( ALWAYS(pSchema!=0) ){
+          HashElem *p;
+
+          nByte += sqlite3GlobalConfig.m.xRoundup(sizeof(HashElem)) * (
+              pSchema->tblHash.count 
+            + pSchema->trigHash.count
+            + pSchema->idxHash.count
+            + pSchema->fkeyHash.count
+          );
+          nByte += sqlite3MallocSize(pSchema->tblHash.ht);
+          nByte += sqlite3MallocSize(pSchema->trigHash.ht);
+          nByte += sqlite3MallocSize(pSchema->idxHash.ht);
+          nByte += sqlite3MallocSize(pSchema->fkeyHash.ht);
+
+          for(p=sqliteHashFirst(&pSchema->trigHash); p; p=sqliteHashNext(p)){
+            sqlite3DeleteTrigger(db, (Trigger*)sqliteHashData(p));
+          }
+          for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
+            sqlite3DeleteTable(db, (Table *)sqliteHashData(p));
+          }
+        }
+      }
+      db->pnBytesFreed = 0;
+      sqlite3BtreeLeaveAll(db);
+
+      *pHighwater = 0;
+      *pCurrent = nByte;
+      break;
+    }
+
+    /*
+    ** *pCurrent gets an accurate estimate of the amount of memory used
+    ** to store all prepared statements.
+    ** *pHighwater is set to zero.
+    */
+    case SQLITE_DBSTATUS_STMT_USED: {
+      struct Vdbe *pVdbe;         /* Used to iterate through VMs */
+      int nByte = 0;              /* Used to accumulate return value */
+
+      db->pnBytesFreed = &nByte;
+      for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pNext){
+        sqlite3VdbeDeleteObject(db, pVdbe);
+      }
+      db->pnBytesFreed = 0;
+
+      *pHighwater = 0;
+      *pCurrent = nByte;
+
+      break;
+    }
+
+    /*
+    ** Set *pCurrent to the total cache hits or misses encountered by all
+    ** pagers the database handle is connected to. *pHighwater is always set 
+    ** to zero.
+    */
+    case SQLITE_DBSTATUS_CACHE_HIT:
+    case SQLITE_DBSTATUS_CACHE_MISS:
+    case SQLITE_DBSTATUS_CACHE_WRITE:{
+      int i;
+      int nRet = 0;
+      assert( SQLITE_DBSTATUS_CACHE_MISS==SQLITE_DBSTATUS_CACHE_HIT+1 );
+      assert( SQLITE_DBSTATUS_CACHE_WRITE==SQLITE_DBSTATUS_CACHE_HIT+2 );
+
+      for(i=0; i<db->nDb; i++){
+        if( db->aDb[i].pBt ){
+          Pager *pPager = sqlite3BtreePager(db->aDb[i].pBt);
+          sqlite3PagerCacheStat(pPager, op, resetFlag, &nRet);
+        }
+      }
+      *pHighwater = 0;
+      *pCurrent = nRet;
+      break;
+    }
+
     default: {
-      return SQLITE_ERROR;
+      rc = SQLITE_ERROR;
     }
   }
-  return SQLITE_OK;
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
 }
 
 /************** End of status.c **********************************************/
@@ -11436,8 +13693,6 @@ SQLITE_API int sqlite3_db_status(
 ** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
 ** All other code has file scope.
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-**
 ** SQLite processes all times and dates as Julian Day numbers.  The
 ** dates and times are stored as the number of days since noon
 ** in Greenwich on November 24, 4714 B.C. according to the Gregorian
@@ -11465,27 +13720,12 @@ SQLITE_API int sqlite3_db_status(
 **      Willmann-Bell, Inc
 **      Richmond, Virginia (USA)
 */
-#include <ctype.h>
+/* #include <stdlib.h> */
+/* #include <assert.h> */
 #include <time.h>
 
 #ifndef SQLITE_OMIT_DATETIME_FUNCS
 
-/*
-** On recent Windows platforms, the localtime_s() function is available
-** as part of the "Secure CRT". It is essentially equivalent to 
-** localtime_r() available under most POSIX platforms, except that the 
-** order of the parameters is reversed.
-**
-** See http://msdn.microsoft.com/en-us/library/a442x3ye(VS.80).aspx.
-**
-** If the user has not indicated to use localtime_r() or localtime_s()
-** already, check for an MSVC build environment that provides 
-** localtime_s().
-*/
-#if !defined(HAVE_LOCALTIME_R) && !defined(HAVE_LOCALTIME_S) && \
-     defined(_MSC_VER) && defined(_CRT_INSECURE_DEPRECATE)
-#define HAVE_LOCALTIME_S 1
-#endif
 
 /*
 ** A structure for holding a single date and time.
@@ -11535,7 +13775,7 @@ static int getDigits(const char *zDate, ...){
     pVal = va_arg(ap, int*);
     val = 0;
     while( N-- ){
-      if( !isdigit(*(u8*)zDate) ){
+      if( !sqlite3Isdigit(*zDate) ){
         goto end_getDigits;
       }
       val = val*10 + *zDate - '0';
@@ -11553,12 +13793,6 @@ end_getDigits:
   return cnt;
 }
 
-/*
-** Read text from z[] and convert into a floating point number.  Return
-** the number of digits converted.
-*/
-#define getValue sqlite3AtoF
-
 /*
 ** Parse a timezone extension on the end of a date-time.
 ** The extension is of the form:
@@ -11579,7 +13813,7 @@ static int parseTimezone(const char *zDate, DateTime *p){
   int sgn = 0;
   int nHr, nMn;
   int c;
-  while( isspace(*(u8*)zDate) ){ zDate++; }
+  while( sqlite3Isspace(*zDate) ){ zDate++; }
   p->tz = 0;
   c = *zDate;
   if( c=='-' ){
@@ -11599,7 +13833,7 @@ static int parseTimezone(const char *zDate, DateTime *p){
   zDate += 5;
   p->tz = sgn*(nMn + nHr*60);
 zulu_time:
-  while( isspace(*(u8*)zDate) ){ zDate++; }
+  while( sqlite3Isspace(*zDate) ){ zDate++; }
   return *zDate!=0;
 }
 
@@ -11623,10 +13857,10 @@ static int parseHhMmSs(const char *zDate, DateTime *p){
       return 1;
     }
     zDate += 2;
-    if( *zDate=='.' && isdigit((u8)zDate[1]) ){
+    if( *zDate=='.' && sqlite3Isdigit(zDate[1]) ){
       double rScale = 1.0;
       zDate++;
-      while( isdigit(*(u8*)zDate) ){
+      while( sqlite3Isdigit(*zDate) ){
         ms = ms*10.0 + *zDate - '0';
         rScale *= 10.0;
         zDate++;
@@ -11711,7 +13945,7 @@ static int parseYyyyMmDd(const char *zDate, DateTime *p){
     return 1;
   }
   zDate += 10;
-  while( isspace(*(u8*)zDate) || 'T'==*(u8*)zDate ){ zDate++; }
+  while( sqlite3Isspace(*zDate) || 'T'==*(u8*)zDate ){ zDate++; }
   if( parseHhMmSs(zDate, p)==0 ){
     /* We got the time */
   }else if( *zDate==0 ){
@@ -11731,14 +13965,18 @@ static int parseYyyyMmDd(const char *zDate, DateTime *p){
 }
 
 /*
-** Set the time to the current time reported by the VFS
+** Set the time to the current time reported by the VFS.
+**
+** Return the number of errors.
 */
-static void setDateTimeToCurrent(sqlite3_context *context, DateTime *p){
-  double r;
+static int setDateTimeToCurrent(sqlite3_context *context, DateTime *p){
   sqlite3 *db = sqlite3_context_db_handle(context);
-  sqlite3OsCurrentTime(db->pVfs, &r);
-  p->iJD = (sqlite3_int64)(r*86400000.0 + 0.5);
-  p->validJD = 1;
+  if( sqlite3OsCurrentTimeInt64(db->pVfs, &p->iJD)==SQLITE_OK ){
+    p->validJD = 1;
+    return 0;
+  }else{
+    return 1;
+  }
 }
 
 /*
@@ -11762,16 +14000,14 @@ static int parseDateOrTime(
   const char *zDate, 
   DateTime *p
 ){
+  double r;
   if( parseYyyyMmDd(zDate,p)==0 ){
     return 0;
   }else if( parseHhMmSs(zDate, p)==0 ){
     return 0;
   }else if( sqlite3StrICmp(zDate,"now")==0){
-    setDateTimeToCurrent(context, p);
-    return 0;
-  }else if( sqlite3IsNumber(zDate, 0, SQLITE_UTF8) ){
-    double r;
-    getValue(zDate, &r);
+    return setDateTimeToCurrent(context, p);
+  }else if( sqlite3AtoF(zDate, &r, sqlite3Strlen30(zDate), SQLITE_UTF8) ){
     p->iJD = (sqlite3_int64)(r*86400000.0 + 0.5);
     p->validJD = 1;
     return 0;
@@ -11840,15 +14076,85 @@ static void clearYMD_HMS_TZ(DateTime *p){
   p->validTZ = 0;
 }
 
+/*
+** On recent Windows platforms, the localtime_s() function is available
+** as part of the "Secure CRT". It is essentially equivalent to 
+** localtime_r() available under most POSIX platforms, except that the 
+** order of the parameters is reversed.
+**
+** See http://msdn.microsoft.com/en-us/library/a442x3ye(VS.80).aspx.
+**
+** If the user has not indicated to use localtime_r() or localtime_s()
+** already, check for an MSVC build environment that provides 
+** localtime_s().
+*/
+#if !defined(HAVE_LOCALTIME_R) && !defined(HAVE_LOCALTIME_S) && \
+     defined(_MSC_VER) && defined(_CRT_INSECURE_DEPRECATE)
+#define HAVE_LOCALTIME_S 1
+#endif
+
 #ifndef SQLITE_OMIT_LOCALTIME
 /*
-** Compute the difference (in milliseconds)
-** between localtime and UTC (a.k.a. GMT)
-** for the time value p where p is in UTC.
+** The following routine implements the rough equivalent of localtime_r()
+** using whatever operating-system specific localtime facility that
+** is available.  This routine returns 0 on success and
+** non-zero on any kind of error.
+**
+** If the sqlite3GlobalConfig.bLocaltimeFault variable is true then this
+** routine will always fail.
 */
-static sqlite3_int64 localtimeOffset(DateTime *p){
+static int osLocaltime(time_t *t, struct tm *pTm){
+  int rc;
+#if (!defined(HAVE_LOCALTIME_R) || !HAVE_LOCALTIME_R) \
+      && (!defined(HAVE_LOCALTIME_S) || !HAVE_LOCALTIME_S)
+  struct tm *pX;
+#if SQLITE_THREADSAFE>0
+  sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
+#endif
+  sqlite3_mutex_enter(mutex);
+  pX = localtime(t);
+#ifndef SQLITE_OMIT_BUILTIN_TEST
+  if( sqlite3GlobalConfig.bLocaltimeFault ) pX = 0;
+#endif
+  if( pX ) *pTm = *pX;
+  sqlite3_mutex_leave(mutex);
+  rc = pX==0;
+#else
+#ifndef SQLITE_OMIT_BUILTIN_TEST
+  if( sqlite3GlobalConfig.bLocaltimeFault ) return 1;
+#endif
+#if defined(HAVE_LOCALTIME_R) && HAVE_LOCALTIME_R
+  rc = localtime_r(t, pTm)==0;
+#else
+  rc = localtime_s(pTm, t);
+#endif /* HAVE_LOCALTIME_R */
+#endif /* HAVE_LOCALTIME_R || HAVE_LOCALTIME_S */
+  return rc;
+}
+#endif /* SQLITE_OMIT_LOCALTIME */
+
+
+#ifndef SQLITE_OMIT_LOCALTIME
+/*
+** Compute the difference (in milliseconds) between localtime and UTC
+** (a.k.a. GMT) for the time value p where p is in UTC. If no error occurs,
+** return this value and set *pRc to SQLITE_OK. 
+**
+** Or, if an error does occur, set *pRc to SQLITE_ERROR. The returned value
+** is undefined in this case.
+*/
+static sqlite3_int64 localtimeOffset(
+  DateTime *p,                    /* Date at which to calculate offset */
+  sqlite3_context *pCtx,          /* Write error here if one occurs */
+  int *pRc                        /* OUT: Error code. SQLITE_OK or ERROR */
+){
   DateTime x, y;
   time_t t;
+  struct tm sLocal;
+
+  /* Initialize the contents of sLocal to avoid a compiler warning. */
+  memset(&sLocal, 0, sizeof(sLocal));
+
   x = *p;
   computeYMD_HMS(&x);
   if( x.Y<1971 || x.Y>=2038 ){
@@ -11865,48 +14171,24 @@ static sqlite3_int64 localtimeOffset(DateTime *p){
   x.tz = 0;
   x.validJD = 0;
   computeJD(&x);
-  t = x.iJD/1000 - 21086676*(i64)10000;
-#ifdef HAVE_LOCALTIME_R
-  {
-    struct tm sLocal;
-    localtime_r(&t, &sLocal);
-    y.Y = sLocal.tm_year + 1900;
-    y.M = sLocal.tm_mon + 1;
-    y.D = sLocal.tm_mday;
-    y.h = sLocal.tm_hour;
-    y.m = sLocal.tm_min;
-    y.s = sLocal.tm_sec;
+  t = (time_t)(x.iJD/1000 - 21086676*(i64)10000);
+  if( osLocaltime(&t, &sLocal) ){
+    sqlite3_result_error(pCtx, "local time unavailable", -1);
+    *pRc = SQLITE_ERROR;
+    return 0;
   }
-#elif defined(HAVE_LOCALTIME_S)
-  {
-    struct tm sLocal;
-    localtime_s(&sLocal, &t);
-    y.Y = sLocal.tm_year + 1900;
-    y.M = sLocal.tm_mon + 1;
-    y.D = sLocal.tm_mday;
-    y.h = sLocal.tm_hour;
-    y.m = sLocal.tm_min;
-    y.s = sLocal.tm_sec;
-  }
-#else
-  {
-    struct tm *pTm;
-    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
-    pTm = localtime(&t);
-    y.Y = pTm->tm_year + 1900;
-    y.M = pTm->tm_mon + 1;
-    y.D = pTm->tm_mday;
-    y.h = pTm->tm_hour;
-    y.m = pTm->tm_min;
-    y.s = pTm->tm_sec;
-    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
-  }
-#endif
+  y.Y = sLocal.tm_year + 1900;
+  y.M = sLocal.tm_mon + 1;
+  y.D = sLocal.tm_mday;
+  y.h = sLocal.tm_hour;
+  y.m = sLocal.tm_min;
+  y.s = sLocal.tm_sec;
   y.validYMD = 1;
   y.validHMS = 1;
   y.validJD = 0;
   y.validTZ = 0;
   computeJD(&y);
+  *pRc = SQLITE_OK;
   return y.iJD - x.iJD;
 }
 #endif /* SQLITE_OMIT_LOCALTIME */
@@ -11930,9 +14212,12 @@ static sqlite3_int64 localtimeOffset(DateTime *p){
 **     localtime
 **     utc
 **
-** Return 0 on success and 1 if there is any kind of error.
+** Return 0 on success and 1 if there is any kind of error. If the error
+** is in a system call (i.e. localtime()), then an error message is written
+** to context pCtx. If the error is an unrecognized modifier, no error is
+** written to pCtx.
 */
-static int parseModifier(const char *zMod, DateTime *p){
+static int parseModifier(sqlite3_context *pCtx, const char *zMod, DateTime *p){
   int rc = 1;
   int n;
   double r;
@@ -11952,9 +14237,8 @@ static int parseModifier(const char *zMod, DateTime *p){
       */
       if( strcmp(z, "localtime")==0 ){
         computeJD(p);
-        p->iJD += localtimeOffset(p);
+        p->iJD += localtimeOffset(p, pCtx, &rc);
         clearYMD_HMS_TZ(p);
-        rc = 0;
       }
       break;
     }
@@ -11967,7 +14251,7 @@ static int parseModifier(const char *zMod, DateTime *p){
       ** seconds since 1970.  Convert to a real julian day number.
       */
       if( strcmp(z, "unixepoch")==0 && p->validJD ){
-        p->iJD = p->iJD/86400 + 21086676*(i64)10000000;
+        p->iJD = (p->iJD + 43200)/86400 + 21086676*(i64)10000000;
         clearYMD_HMS_TZ(p);
         rc = 0;
       }
@@ -11975,11 +14259,12 @@ static int parseModifier(const char *zMod, DateTime *p){
       else if( strcmp(z, "utc")==0 ){
         sqlite3_int64 c1;
         computeJD(p);
-        c1 = localtimeOffset(p);
-        p->iJD -= c1;
-        clearYMD_HMS_TZ(p);
-        p->iJD += c1 - localtimeOffset(p);
-        rc = 0;
+        c1 = localtimeOffset(p, pCtx, &rc);
+        if( rc==SQLITE_OK ){
+          p->iJD -= c1;
+          clearYMD_HMS_TZ(p);
+          p->iJD += c1 - localtimeOffset(p, pCtx, &rc);
+        }
       }
 #endif
       break;
@@ -11992,8 +14277,9 @@ static int parseModifier(const char *zMod, DateTime *p){
       ** weekday N where 0==Sunday, 1==Monday, and so forth.  If the
       ** date is already on the appropriate weekday, this is a no-op.
       */
-      if( strncmp(z, "weekday ", 8)==0 && getValue(&z[8],&r)>0
-                 && (n=(int)r)==r && n>=0 && r<7 ){
+      if( strncmp(z, "weekday ", 8)==0
+               && sqlite3AtoF(&z[8], &r, sqlite3Strlen30(&z[8]), SQLITE_UTF8)
+               && (n=(int)r)==r && n>=0 && r<7 ){
         sqlite3_int64 Z;
         computeYMD_HMS(p);
         p->validTZ = 0;
@@ -12047,8 +14333,12 @@ static int parseModifier(const char *zMod, DateTime *p){
     case '7':
     case '8':
     case '9': {
-      n = getValue(z, &r);
-      assert( n>=1 );
+      double rRounder;
+      for(n=1; z[n] && z[n]!=':' && !sqlite3Isspace(z[n]); n++){}
+      if( !sqlite3AtoF(z, &r, n, SQLITE_UTF8) ){
+        rc = 1;
+        break;
+      }
       if( z[n]==':' ){
         /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the
         ** specified number of hours, minutes, seconds, and fractional seconds
@@ -12058,7 +14348,7 @@ static int parseModifier(const char *zMod, DateTime *p){
         const char *z2 = z;
         DateTime tx;
         sqlite3_int64 day;
-        if( !isdigit(*(u8*)z2) ) z2++;
+        if( !sqlite3Isdigit(*z2) ) z2++;
         memset(&tx, 0, sizeof(tx));
         if( parseHhMmSs(z2, &tx) ) break;
         computeJD(&tx);
@@ -12073,20 +14363,21 @@ static int parseModifier(const char *zMod, DateTime *p){
         break;
       }
       z += n;
-      while( isspace(*(u8*)z) ) z++;
+      while( sqlite3Isspace(*z) ) z++;
       n = sqlite3Strlen30(z);
       if( n>10 || n<3 ) break;
       if( z[n-1]=='s' ){ z[n-1] = 0; n--; }
       computeJD(p);
       rc = 0;
+      rRounder = r<0 ? -0.5 : +0.5;
       if( n==3 && strcmp(z,"day")==0 ){
-        p->iJD += (sqlite3_int64)(r*86400000.0 + 0.5);
+        p->iJD += (sqlite3_int64)(r*86400000.0 + rRounder);
       }else if( n==4 && strcmp(z,"hour")==0 ){
-        p->iJD += (sqlite3_int64)(r*(86400000.0/24.0) + 0.5);
+        p->iJD += (sqlite3_int64)(r*(86400000.0/24.0) + rRounder);
       }else if( n==6 && strcmp(z,"minute")==0 ){
-        p->iJD += (sqlite3_int64)(r*(86400000.0/(24.0*60.0)) + 0.5);
+        p->iJD += (sqlite3_int64)(r*(86400000.0/(24.0*60.0)) + rRounder);
       }else if( n==6 && strcmp(z,"second")==0 ){
-        p->iJD += (sqlite3_int64)(r*(86400000.0/(24.0*60.0*60.0)) + 0.5);
+        p->iJD += (sqlite3_int64)(r*(86400000.0/(24.0*60.0*60.0)) + rRounder);
       }else if( n==5 && strcmp(z,"month")==0 ){
         int x, y;
         computeYMD_HMS(p);
@@ -12098,13 +14389,17 @@ static int parseModifier(const char *zMod, DateTime *p){
         computeJD(p);
         y = (int)r;
         if( y!=r ){
-          p->iJD += (sqlite3_int64)((r - y)*30.0*86400000.0 + 0.5);
+          p->iJD += (sqlite3_int64)((r - y)*30.0*86400000.0 + rRounder);
         }
       }else if( n==4 && strcmp(z,"year")==0 ){
+        int y = (int)r;
         computeYMD_HMS(p);
-        p->Y += (int)r;
+        p->Y += y;
         p->validJD = 0;
         computeJD(p);
+        if( y!=r ){
+          p->iJD += (sqlite3_int64)((r - y)*365.0*86400000.0 + rRounder);
+        }
       }else{
         rc = 1;
       }
@@ -12138,8 +14433,9 @@ static int isDate(
   int eType;
   memset(p, 0, sizeof(*p));
   if( argc==0 ){
-    setDateTimeToCurrent(context, p);
-  }else if( (eType = sqlite3_value_type(argv[0]))==SQLITE_FLOAT
+    return setDateTimeToCurrent(context, p);
+  }
+  if( (eType = sqlite3_value_type(argv[0]))==SQLITE_FLOAT
                    || eType==SQLITE_INTEGER ){
     p->iJD = (sqlite3_int64)(sqlite3_value_double(argv[0])*86400000.0 + 0.5);
     p->validJD = 1;
@@ -12150,9 +14446,8 @@ static int isDate(
     }
   }
   for(i=1; i<argc; i++){
-    if( (z = sqlite3_value_text(argv[i]))==0 || parseModifier((char*)z, p) ){
-      return 1;
-    }
+    z = sqlite3_value_text(argv[i]);
+    if( z==0 || parseModifier(context, (char*)z, p) ) return 1;
   }
   return 0;
 }
@@ -12304,6 +14599,10 @@ static void strftimeFunc(
       i++;
     }
   }
+  testcase( n==sizeof(zBuf)-1 );
+  testcase( n==sizeof(zBuf) );
+  testcase( n==(u64)db->aLimit[SQLITE_LIMIT_LENGTH]+1 );
+  testcase( n==(u64)db->aLimit[SQLITE_LIMIT_LENGTH] );
   if( n<sizeof(zBuf) ){
     z = zBuf;
   }else if( n>(u64)db->aLimit[SQLITE_LIMIT_LENGTH] ){
@@ -12361,8 +14660,8 @@ static void strftimeFunc(
         case 'm':  sqlite3_snprintf(3, &z[j],"%02d",x.M); j+=2; break;
         case 'M':  sqlite3_snprintf(3, &z[j],"%02d",x.m); j+=2; break;
         case 's': {
-          sqlite3_snprintf(30,&z[j],"%d",
-                           (int)(x.iJD/1000.0 - 210866760000.0));
+          sqlite3_snprintf(30,&z[j],"%lld",
+                           (i64)(x.iJD/1000 - 21086676*(i64)10000));
           j += sqlite3Strlen30(&z[j]);
           break;
         }
@@ -12447,29 +14746,29 @@ static void currentTimeFunc(
   time_t t;
   char *zFormat = (char *)sqlite3_user_data(context);
   sqlite3 *db;
-  double rT;
+  sqlite3_int64 iT;
+  struct tm *pTm;
+  struct tm sNow;
   char zBuf[20];
 
-  db = sqlite3_context_db_handle(context);
-  sqlite3OsCurrentTime(db->pVfs, &rT);
-  t = 86400.0*(rT - 2440587.5) + 0.5;
-#ifdef HAVE_GMTIME_R
-  {
-    struct tm sNow;
-    gmtime_r(&t, &sNow);
-    strftime(zBuf, 20, zFormat, &sNow);
-  }
-#else
-  {
-    struct tm *pTm;
-    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
-    pTm = gmtime(&t);
-    strftime(zBuf, 20, zFormat, pTm);
-    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
-  }
-#endif
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
 
-  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  db = sqlite3_context_db_handle(context);
+  if( sqlite3OsCurrentTimeInt64(db->pVfs, &iT) ) return;
+  t = iT/1000 - 10000*(sqlite3_int64)21086676;
+#ifdef HAVE_GMTIME_R
+  pTm = gmtime_r(&t, &sNow);
+#else
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+  pTm = gmtime(&t);
+  if( pTm ) memcpy(&sNow, pTm, sizeof(sNow));
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+#endif
+  if( pTm ){
+    strftime(zBuf, 20, zFormat, &sNow);
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
 }
 #endif
 
@@ -12491,8 +14790,8 @@ SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void){
     FUNCTION(current_date,      0, 0, 0, cdateFunc     ),
 #else
     STR_FUNCTION(current_time,      0, "%H:%M:%S",          0, currentTimeFunc),
-    STR_FUNCTION(current_timestamp, 0, "%Y-%m-%d",          0, currentTimeFunc),
-    STR_FUNCTION(current_date,      0, "%Y-%m-%d %H:%M:%S", 0, currentTimeFunc),
+    STR_FUNCTION(current_date,      0, "%Y-%m-%d",          0, currentTimeFunc),
+    STR_FUNCTION(current_timestamp, 0, "%Y-%m-%d %H:%M:%S", 0, currentTimeFunc),
 #endif
   };
   int i;
@@ -12520,8 +14819,6 @@ SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void){
 **
 ** This file contains OS interface code that is common to all
 ** architectures.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #define _SQLITE_OS_C_ 1
 #undef _SQLITE_OS_C_
@@ -12536,21 +14833,30 @@ SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void){
 ** The following functions are instrumented for malloc() failure 
 ** testing:
 **
-**     sqlite3OsOpen()
 **     sqlite3OsRead()
 **     sqlite3OsWrite()
 **     sqlite3OsSync()
+**     sqlite3OsFileSize()
 **     sqlite3OsLock()
+**     sqlite3OsCheckReservedLock()
+**     sqlite3OsFileControl()
+**     sqlite3OsShmMap()
+**     sqlite3OsOpen()
+**     sqlite3OsDelete()
+**     sqlite3OsAccess()
+**     sqlite3OsFullPathname()
 **
 */
-#if defined(SQLITE_TEST) && (SQLITE_OS_WIN==0)
-  #define DO_OS_MALLOC_TEST if (1) {            \
-    void *pTstAlloc = sqlite3Malloc(10);       \
-    if (!pTstAlloc) return SQLITE_IOERR_NOMEM;  \
-    sqlite3_free(pTstAlloc);                    \
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
+  #define DO_OS_MALLOC_TEST(x)                                       \
+  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3IsMemJournal(x))) {  \
+    void *pTstAlloc = sqlite3Malloc(10);                             \
+    if (!pTstAlloc) return SQLITE_IOERR_NOMEM;                       \
+    sqlite3_free(pTstAlloc);                                         \
   }
 #else
-  #define DO_OS_MALLOC_TEST
+  #define DO_OS_MALLOC_TEST(x)
 #endif
 
 /*
@@ -12568,38 +14874,52 @@ SQLITE_PRIVATE int sqlite3OsClose(sqlite3_file *pId){
   return rc;
 }
 SQLITE_PRIVATE int sqlite3OsRead(sqlite3_file *id, void *pBuf, int amt, i64 offset){
-  DO_OS_MALLOC_TEST;
+  DO_OS_MALLOC_TEST(id);
   return id->pMethods->xRead(id, pBuf, amt, offset);
 }
 SQLITE_PRIVATE int sqlite3OsWrite(sqlite3_file *id, const void *pBuf, int amt, i64 offset){
-  DO_OS_MALLOC_TEST;
+  DO_OS_MALLOC_TEST(id);
   return id->pMethods->xWrite(id, pBuf, amt, offset);
 }
 SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file *id, i64 size){
   return id->pMethods->xTruncate(id, size);
 }
 SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file *id, int flags){
-  DO_OS_MALLOC_TEST;
+  DO_OS_MALLOC_TEST(id);
   return id->pMethods->xSync(id, flags);
 }
 SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file *id, i64 *pSize){
-  DO_OS_MALLOC_TEST;
+  DO_OS_MALLOC_TEST(id);
   return id->pMethods->xFileSize(id, pSize);
 }
 SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file *id, int lockType){
-  DO_OS_MALLOC_TEST;
+  DO_OS_MALLOC_TEST(id);
   return id->pMethods->xLock(id, lockType);
 }
 SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file *id, int lockType){
   return id->pMethods->xUnlock(id, lockType);
 }
 SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){
-  DO_OS_MALLOC_TEST;
+  DO_OS_MALLOC_TEST(id);
   return id->pMethods->xCheckReservedLock(id, pResOut);
 }
+
+/*
+** Use sqlite3OsFileControl() when we are doing something that might fail
+** and we need to know about the failures.  Use sqlite3OsFileControlHint()
+** when simply tossing information over the wall to the VFS and we do not
+** really care if the VFS receives and understands the information since it
+** is only a hint and can be safely ignored.  The sqlite3OsFileControlHint()
+** routine has no return value since the return value would be meaningless.
+*/
 SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
+  DO_OS_MALLOC_TEST(id);
   return id->pMethods->xFileControl(id, op, pArg);
 }
+SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file *id, int op, void *pArg){
+  (void)id->pMethods->xFileControl(id, op, pArg);
+}
+
 SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id){
   int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
   return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
@@ -12607,6 +14927,25 @@ SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id){
 SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
   return id->pMethods->xDeviceCharacteristics(id);
 }
+SQLITE_PRIVATE int sqlite3OsShmLock(sqlite3_file *id, int offset, int n, int flags){
+  return id->pMethods->xShmLock(id, offset, n, flags);
+}
+SQLITE_PRIVATE void sqlite3OsShmBarrier(sqlite3_file *id){
+  id->pMethods->xShmBarrier(id);
+}
+SQLITE_PRIVATE int sqlite3OsShmUnmap(sqlite3_file *id, int deleteFlag){
+  return id->pMethods->xShmUnmap(id, deleteFlag);
+}
+SQLITE_PRIVATE int sqlite3OsShmMap(
+  sqlite3_file *id,               /* Database file handle */
+  int iPage,
+  int pgsz,
+  int bExtend,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Pointer to mapping */
+){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
+}
 
 /*
 ** The next group of routines are convenience wrappers around the
@@ -12619,10 +14958,19 @@ SQLITE_PRIVATE int sqlite3OsOpen(
   int flags, 
   int *pFlagsOut
 ){
-  DO_OS_MALLOC_TEST;
-  return pVfs->xOpen(pVfs, zPath, pFile, flags, pFlagsOut);
+  int rc;
+  DO_OS_MALLOC_TEST(0);
+  /* 0x87f7f is a mask of SQLITE_OPEN_ flags that are valid to be passed
+  ** down into the VFS layer.  Some SQLITE_OPEN_ flags (for example,
+  ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
+  ** reaching the VFS. */
+  rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x87f7f, pFlagsOut);
+  assert( rc==SQLITE_OK || pFile->pMethods==0 );
+  return rc;
 }
 SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  DO_OS_MALLOC_TEST(0);
+  assert( dirSync==0 || dirSync==1 );
   return pVfs->xDelete(pVfs, zPath, dirSync);
 }
 SQLITE_PRIVATE int sqlite3OsAccess(
@@ -12631,7 +14979,7 @@ SQLITE_PRIVATE int sqlite3OsAccess(
   int flags, 
   int *pResOut
 ){
-  DO_OS_MALLOC_TEST;
+  DO_OS_MALLOC_TEST(0);
   return pVfs->xAccess(pVfs, zPath, flags, pResOut);
 }
 SQLITE_PRIVATE int sqlite3OsFullPathname(
@@ -12640,6 +14988,8 @@ SQLITE_PRIVATE int sqlite3OsFullPathname(
   int nPathOut, 
   char *zPathOut
 ){
+  DO_OS_MALLOC_TEST(0);
+  zPathOut[0] = 0;
   return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
 }
 #ifndef SQLITE_OMIT_LOAD_EXTENSION
@@ -12649,7 +14999,7 @@ SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
 SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
   pVfs->xDlError(pVfs, nByte, zBufOut);
 }
-void (*sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHdle, const char *zSym))(void){
+SQLITE_PRIVATE void (*sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHdle, const char *zSym))(void){
   return pVfs->xDlSym(pVfs, pHdle, zSym);
 }
 SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *pVfs, void *pHandle){
@@ -12662,8 +15012,22 @@ SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufO
 SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *pVfs, int nMicro){
   return pVfs->xSleep(pVfs, nMicro);
 }
-SQLITE_PRIVATE int sqlite3OsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
-  return pVfs->xCurrentTime(pVfs, pTimeOut);
+SQLITE_PRIVATE int sqlite3OsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
+  int rc;
+  /* IMPLEMENTATION-OF: R-49045-42493 SQLite will use the xCurrentTimeInt64()
+  ** method to get the current date and time if that method is available
+  ** (if iVersion is 2 or greater and the function pointer is not NULL) and
+  ** will fall back to xCurrentTime() if xCurrentTimeInt64() is
+  ** unavailable.
+  */
+  if( pVfs->iVersion>=2 && pVfs->xCurrentTimeInt64 ){
+    rc = pVfs->xCurrentTimeInt64(pVfs, pTimeOut);
+  }else{
+    double r;
+    rc = pVfs->xCurrentTime(pVfs, &r);
+    *pTimeOut = (sqlite3_int64)(r*86400000.0);
+  }
+  return rc;
 }
 
 SQLITE_PRIVATE int sqlite3OsOpenMalloc(
@@ -12675,7 +15039,7 @@ SQLITE_PRIVATE int sqlite3OsOpenMalloc(
 ){
   int rc = SQLITE_NOMEM;
   sqlite3_file *pFile;
-  pFile = (sqlite3_file *)sqlite3Malloc(pVfs->szOsFile);
+  pFile = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile);
   if( pFile ){
     rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags);
     if( rc!=SQLITE_OK ){
@@ -12694,6 +15058,19 @@ SQLITE_PRIVATE int sqlite3OsCloseFree(sqlite3_file *pFile){
   return rc;
 }
 
+/*
+** This function is a wrapper around the OS specific implementation of
+** sqlite3_os_init(). The purpose of the wrapper is to provide the
+** ability to simulate a malloc failure, so that the handling of an
+** error in sqlite3_os_init() by the upper layers can be tested.
+*/
+SQLITE_PRIVATE int sqlite3OsInit(void){
+  void *p = sqlite3_malloc(10);
+  if( p==0 ) return SQLITE_NOMEM;
+  sqlite3_free(p);
+  return sqlite3_os_init();
+}
+
 /*
 ** The list of all registered VFS implementations.
 */
@@ -12751,12 +15128,12 @@ static void vfsUnlink(sqlite3_vfs *pVfs){
 ** true.
 */
 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
-  sqlite3_mutex *mutex = 0;
+  MUTEX_LOGIC(sqlite3_mutex *mutex;)
 #ifndef SQLITE_OMIT_AUTOINIT
   int rc = sqlite3_initialize();
   if( rc ) return rc;
 #endif
-  mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
+  MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
   sqlite3_mutex_enter(mutex);
   vfsUnlink(pVfs);
   if( makeDflt || vfsList==0 ){
@@ -12798,10 +15175,6 @@ SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){
 **
 *************************************************************************
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-*/
-
-/*
 ** This file contains code to support the concept of "benign" 
 ** malloc failures (when the xMalloc() or xRealloc() method of the
 ** sqlite3_mem_methods structure fails to allocate a block of memory
@@ -12896,8 +15269,6 @@ SQLITE_PRIVATE void sqlite3EndBenignMalloc(void){
 ** here always fail.  SQLite will not operate with these drivers.  These
 ** are merely placeholders.  Real drivers must be substituted using
 ** sqlite3_config() before SQLite will operate.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -12959,9 +15330,31 @@ SQLITE_PRIVATE void sqlite3MemSetDefault(void){
 ** to obtain the memory it needs.
 **
 ** This file contains implementations of the low-level memory allocation
-** routines specified in the sqlite3_mem_methods object.
+** routines specified in the sqlite3_mem_methods object.  The content of
+** this file is only used if SQLITE_SYSTEM_MALLOC is defined.  The
+** SQLITE_SYSTEM_MALLOC macro is defined automatically if neither the
+** SQLITE_MEMDEBUG nor the SQLITE_WIN32_MALLOC macros are defined.  The
+** default configuration is to use memory allocation routines in this
+** file.
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+** C-preprocessor macro summary:
+**
+**    HAVE_MALLOC_USABLE_SIZE     The configure script sets this symbol if
+**                                the malloc_usable_size() interface exists
+**                                on the target platform.  Or, this symbol
+**                                can be set manually, if desired.
+**                                If an equivalent interface exists by
+**                                a different name, using a separate -D
+**                                option to rename it.
+**
+**    SQLITE_WITHOUT_ZONEMALLOC   Some older macs lack support for the zone
+**                                memory allocator.  Set this symbol to enable
+**                                building on older macs.
+**
+**    SQLITE_WITHOUT_MSIZE        Set this symbol to disable the use of
+**                                _msize() on windows systems.  This might
+**                                be necessary when compiling for Delphi,
+**                                for example.
 */
 
 /*
@@ -12971,6 +15364,55 @@ SQLITE_PRIVATE void sqlite3MemSetDefault(void){
 */
 #ifdef SQLITE_SYSTEM_MALLOC
 
+/*
+** The MSVCRT has malloc_usable_size() but it is called _msize().
+** The use of _msize() is automatic, but can be disabled by compiling
+** with -DSQLITE_WITHOUT_MSIZE
+*/
+#if defined(_MSC_VER) && !defined(SQLITE_WITHOUT_MSIZE)
+# define SQLITE_MALLOCSIZE _msize
+#endif
+
+#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
+
+/*
+** Use the zone allocator available on apple products unless the
+** SQLITE_WITHOUT_ZONEMALLOC symbol is defined.
+*/
+#include <sys/sysctl.h>
+#include <malloc/malloc.h>
+#include <libkern/OSAtomic.h>
+static malloc_zone_t* _sqliteZone_;
+#define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x))
+#define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x));
+#define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y))
+#define SQLITE_MALLOCSIZE(x) \
+        (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x))
+
+#else /* if not __APPLE__ */
+
+/*
+** Use standard C library malloc and free on non-Apple systems.  
+** Also used by Apple systems if SQLITE_WITHOUT_ZONEMALLOC is defined.
+*/
+#define SQLITE_MALLOC(x)    malloc(x)
+#define SQLITE_FREE(x)      free(x)
+#define SQLITE_REALLOC(x,y) realloc((x),(y))
+
+#if (defined(_MSC_VER) && !defined(SQLITE_WITHOUT_MSIZE)) \
+      || (defined(HAVE_MALLOC_H) && defined(HAVE_MALLOC_USABLE_SIZE))
+# include <malloc.h>    /* Needed for malloc_usable_size on linux */
+#endif
+#ifdef HAVE_MALLOC_USABLE_SIZE
+# ifndef SQLITE_MALLOCSIZE
+#  define SQLITE_MALLOCSIZE(x) malloc_usable_size(x)
+# endif
+#else
+# undef SQLITE_MALLOCSIZE
+#endif
+
+#endif /* __APPLE__ or not __APPLE__ */
+
 /*
 ** Like malloc(), but remember the size of the allocation
 ** so that we can find it later using sqlite3MemSize().
@@ -12980,15 +15422,27 @@ SQLITE_PRIVATE void sqlite3MemSetDefault(void){
 ** routines.
 */
 static void *sqlite3MemMalloc(int nByte){
+#ifdef SQLITE_MALLOCSIZE
+  void *p = SQLITE_MALLOC( nByte );
+  if( p==0 ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
+  }
+  return p;
+#else
   sqlite3_int64 *p;
   assert( nByte>0 );
-  nByte = (nByte+7)&~7;
-  p = malloc( nByte+8 );
+  nByte = ROUND8(nByte);
+  p = SQLITE_MALLOC( nByte+8 );
   if( p ){
     p[0] = nByte;
     p++;
+  }else{
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
   }
   return (void *)p;
+#endif
 }
 
 /*
@@ -13000,10 +15454,30 @@ static void *sqlite3MemMalloc(int nByte){
 ** by higher-level routines.
 */
 static void sqlite3MemFree(void *pPrior){
+#ifdef SQLITE_MALLOCSIZE
+  SQLITE_FREE(pPrior);
+#else
   sqlite3_int64 *p = (sqlite3_int64*)pPrior;
   assert( pPrior!=0 );
   p--;
-  free(p);
+  SQLITE_FREE(p);
+#endif
+}
+
+/*
+** Report the allocated size of a prior return from xMalloc()
+** or xRealloc().
+*/
+static int sqlite3MemSize(void *pPrior){
+#ifdef SQLITE_MALLOCSIZE
+  return pPrior ? (int)SQLITE_MALLOCSIZE(pPrior) : 0;
+#else
+  sqlite3_int64 *p;
+  if( pPrior==0 ) return 0;
+  p = (sqlite3_int64*)pPrior;
+  p--;
+  return (int)p[0];
+#endif
 }
 
 /*
@@ -13017,42 +15491,73 @@ static void sqlite3MemFree(void *pPrior){
 ** routines and redirected to xFree.
 */
 static void *sqlite3MemRealloc(void *pPrior, int nByte){
+#ifdef SQLITE_MALLOCSIZE
+  void *p = SQLITE_REALLOC(pPrior, nByte);
+  if( p==0 ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM,
+      "failed memory resize %u to %u bytes",
+      SQLITE_MALLOCSIZE(pPrior), nByte);
+  }
+  return p;
+#else
   sqlite3_int64 *p = (sqlite3_int64*)pPrior;
   assert( pPrior!=0 && nByte>0 );
-  nByte = (nByte+7)&~7;
-  p = (sqlite3_int64*)pPrior;
+  assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */
   p--;
-  p = realloc(p, nByte+8 );
+  p = SQLITE_REALLOC(p, nByte+8 );
   if( p ){
     p[0] = nByte;
     p++;
+  }else{
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM,
+      "failed memory resize %u to %u bytes",
+      sqlite3MemSize(pPrior), nByte);
   }
   return (void*)p;
-}
-
-/*
-** Report the allocated size of a prior return from xMalloc()
-** or xRealloc().
-*/
-static int sqlite3MemSize(void *pPrior){
-  sqlite3_int64 *p;
-  if( pPrior==0 ) return 0;
-  p = (sqlite3_int64*)pPrior;
-  p--;
-  return (int)p[0];
+#endif
 }
 
 /*
 ** Round up a request size to the next valid allocation size.
 */
 static int sqlite3MemRoundup(int n){
-  return (n+7) & ~7;
+  return ROUND8(n);
 }
 
 /*
 ** Initialize this module.
 */
 static int sqlite3MemInit(void *NotUsed){
+#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
+  int cpuCount;
+  size_t len;
+  if( _sqliteZone_ ){
+    return SQLITE_OK;
+  }
+  len = sizeof(cpuCount);
+  /* One usually wants to use hw.acctivecpu for MT decisions, but not here */
+  sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
+  if( cpuCount>1 ){
+    /* defer MT decisions to system malloc */
+    _sqliteZone_ = malloc_default_zone();
+  }else{
+    /* only 1 core, use our own zone to contention over global locks, 
+    ** e.g. we have our own dedicated locks */
+    bool success;
+    malloc_zone_t* newzone = malloc_create_zone(4096, 0);
+    malloc_set_zone_name(newzone, "Sqlite_Heap");
+    do{
+      success = OSAtomicCompareAndSwapPtrBarrier(NULL, newzone, 
+                                 (void * volatile *)&_sqliteZone_);
+    }while(!_sqliteZone_);
+    if( !success ){
+      /* somebody registered a zone first */
+      malloc_destroy_zone(newzone);
+    }
+  }
+#endif
   UNUSED_PARAMETER(NotUsed);
   return SQLITE_OK;
 }
@@ -13109,8 +15614,6 @@ SQLITE_PRIVATE void sqlite3MemSetDefault(void){
 **
 ** This file contains implementations of the low-level memory allocation
 ** routines specified in the sqlite3_mem_methods object.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -13129,6 +15632,7 @@ SQLITE_PRIVATE void sqlite3MemSetDefault(void){
 # define backtrace(A,B) 1
 # define backtrace_symbols_fd(A,B,C)
 #endif
+/* #include <stdio.h> */
 
 /*
 ** Each memory allocation looks like this:
@@ -13148,7 +15652,8 @@ struct MemBlockHdr {
   struct MemBlockHdr *pNext, *pPrev;  /* Linked list of all unfreed memory */
   char nBacktrace;                    /* Number of backtraces on this alloc */
   char nBacktraceSlots;               /* Available backtrace slots */
-  short nTitle;                       /* Bytes of title; includes '\0' */
+  u8 nTitle;                          /* Bytes of title; includes '\0' */
+  u8 eType;                           /* Allocation type code */
   int iForeGuard;                     /* Guard word for sanity */
 };
 
@@ -13217,7 +15722,7 @@ static struct {
 ** Adjust memory usage statistics
 */
 static void adjustStats(int iSize, int increment){
-  int i = ((iSize+7)&~7)/8;
+  int i = ROUND8(iSize)/8;
   if( i>NCSIZE-1 ){
     i = NCSIZE - 1;
   }
@@ -13248,13 +15753,15 @@ static struct MemBlockHdr *sqlite3MemsysGetHeader(void *pAllocation){
   p = (struct MemBlockHdr*)pAllocation;
   p--;
   assert( p->iForeGuard==(int)FOREGUARD );
-  nReserve = (p->iSize+7)&~7;
+  nReserve = ROUND8(p->iSize);
   pInt = (int*)pAllocation;
   pU8 = (u8*)pAllocation;
   assert( pInt[nReserve/sizeof(int)]==(int)REARGUARD );
-  assert( (nReserve-0)<=p->iSize || pU8[nReserve-1]==0x65 );
-  assert( (nReserve-1)<=p->iSize || pU8[nReserve-2]==0x65 );
-  assert( (nReserve-2)<=p->iSize || pU8[nReserve-3]==0x65 );
+  /* This checks any of the "extra" bytes allocated due
+  ** to rounding up to an 8 byte boundary to ensure 
+  ** they haven't been overwritten.
+  */
+  while( nReserve-- > p->iSize ) assert( pU8[nReserve]==0x65 );
   return p;
 }
 
@@ -13275,6 +15782,7 @@ static int sqlite3MemSize(void *p){
 */
 static int sqlite3MemInit(void *NotUsed){
   UNUSED_PARAMETER(NotUsed);
+  assert( (sizeof(struct MemBlockHdr)&7) == 0 );
   if( !sqlite3GlobalConfig.bMemstat ){
     /* If memory status is enabled, then the malloc.c wrapper will already
     ** hold the STATIC_MEM mutex when the routines here are invoked. */
@@ -13295,7 +15803,32 @@ static void sqlite3MemShutdown(void *NotUsed){
 ** Round up a request size to the next valid allocation size.
 */
 static int sqlite3MemRoundup(int n){
-  return (n+7) & ~7;
+  return ROUND8(n);
+}
+
+/*
+** Fill a buffer with pseudo-random bytes.  This is used to preset
+** the content of a new memory allocation to unpredictable values and
+** to clear the content of a freed allocation to unpredictable values.
+*/
+static void randomFill(char *pBuf, int nByte){
+  unsigned int x, y, r;
+  x = SQLITE_PTR_TO_INT(pBuf);
+  y = nByte | 1;
+  while( nByte >= 4 ){
+    x = (x>>1) ^ (-(x&1) & 0xd0000001);
+    y = y*1103515245 + 12345;
+    r = x ^ y;
+    *(int*)pBuf = r;
+    pBuf += 4;
+    nByte -= 4;
+  }
+  while( nByte-- > 0 ){
+    x = (x>>1) ^ (-(x&1) & 0xd0000001);
+    y = y*1103515245 + 12345;
+    r = x ^ y;
+    *(pBuf++) = r & 0xff;
+  }
 }
 
 /*
@@ -13311,7 +15844,7 @@ static void *sqlite3MemMalloc(int nByte){
   int nReserve;
   sqlite3_mutex_enter(mem.mutex);
   assert( mem.disallow==0 );
-  nReserve = (nByte+7)&~7;
+  nReserve = ROUND8(nByte);
   totalSize = nReserve + sizeof(*pHdr) + sizeof(int) +
                mem.nBacktrace*sizeof(void*) + mem.nTitle;
   p = malloc(totalSize);
@@ -13328,12 +15861,14 @@ static void *sqlite3MemMalloc(int nByte){
     }
     mem.pLast = pHdr;
     pHdr->iForeGuard = FOREGUARD;
+    pHdr->eType = MEMTYPE_HEAP;
     pHdr->nBacktraceSlots = mem.nBacktrace;
     pHdr->nTitle = mem.nTitle;
     if( mem.nBacktrace ){
       void *aAddr[40];
       pHdr->nBacktrace = backtrace(aAddr, mem.nBacktrace+1)-1;
       memcpy(pBt, &aAddr[1], pHdr->nBacktrace*sizeof(void*));
+      assert(pBt[0]);
       if( mem.xBacktrace ){
         mem.xBacktrace(nByte, pHdr->nBacktrace-1, &aAddr[1]);
       }
@@ -13347,7 +15882,8 @@ static void *sqlite3MemMalloc(int nByte){
     adjustStats(nByte, +1);
     pInt = (int*)&pHdr[1];
     pInt[nReserve/sizeof(int)] = REARGUARD;
-    memset(pInt, 0x65, nReserve);
+    randomFill((char*)pInt, nByte);
+    memset(((char*)pInt)+nByte, 0x65, nReserve-nByte);
     p = (void*)pInt;
   }
   sqlite3_mutex_leave(mem.mutex);
@@ -13361,7 +15897,8 @@ static void sqlite3MemFree(void *pPrior){
   struct MemBlockHdr *pHdr;
   void **pBt;
   char *z;
-  assert( sqlite3GlobalConfig.bMemstat || mem.mutex!=0 );
+  assert( sqlite3GlobalConfig.bMemstat || sqlite3GlobalConfig.bCoreMutex==0 
+       || mem.mutex!=0 );
   pHdr = sqlite3MemsysGetHeader(pPrior);
   pBt = (void**)pHdr;
   pBt -= pHdr->nBacktraceSlots;
@@ -13383,8 +15920,8 @@ static void sqlite3MemFree(void *pPrior){
   z = (char*)pBt;
   z -= pHdr->nTitle;
   adjustStats(pHdr->iSize, -1);
-  memset(z, 0x2b, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
-                  pHdr->iSize + sizeof(int) + pHdr->nTitle);
+  randomFill(z, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
+                pHdr->iSize + sizeof(int) + pHdr->nTitle);
   free(z);
   sqlite3_mutex_leave(mem.mutex);  
 }
@@ -13402,12 +15939,13 @@ static void *sqlite3MemRealloc(void *pPrior, int nByte){
   struct MemBlockHdr *pOldHdr;
   void *pNew;
   assert( mem.disallow==0 );
+  assert( (nByte & 7)==0 );     /* EV: R-46199-30249 */
   pOldHdr = sqlite3MemsysGetHeader(pPrior);
   pNew = sqlite3MemMalloc(nByte);
   if( pNew ){
     memcpy(pNew, pPrior, nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize);
     if( nByte>pOldHdr->iSize ){
-      memset(&((char*)pNew)[pOldHdr->iSize], 0x2b, nByte - pOldHdr->iSize);
+      randomFill(&((char*)pNew)[pOldHdr->iSize], nByte - pOldHdr->iSize);
     }
     sqlite3MemFree(pPrior);
   }
@@ -13432,6 +15970,62 @@ SQLITE_PRIVATE void sqlite3MemSetDefault(void){
   sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
 }
 
+/*
+** Set the "type" of an allocation.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugSetType(void *p, u8 eType){
+  if( p && sqlite3GlobalConfig.m.xMalloc==sqlite3MemMalloc ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );
+    pHdr->eType = eType;
+  }
+}
+
+/*
+** Return TRUE if the mask of type in eType matches the type of the
+** allocation p.  Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation.  For example:
+**
+**     assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
+*/
+SQLITE_PRIVATE int sqlite3MemdebugHasType(void *p, u8 eType){
+  int rc = 1;
+  if( p && sqlite3GlobalConfig.m.xMalloc==sqlite3MemMalloc ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
+    if( (pHdr->eType&eType)==0 ){
+      rc = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Return TRUE if the mask of type in eType matches no bits of the type of the
+** allocation p.  Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation.  For example:
+**
+**     assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
+*/
+SQLITE_PRIVATE int sqlite3MemdebugNoType(void *p, u8 eType){
+  int rc = 1;
+  if( p && sqlite3GlobalConfig.m.xMalloc==sqlite3MemMalloc ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
+    if( (pHdr->eType&eType)!=0 ){
+      rc = 0;
+    }
+  }
+  return rc;
+}
+
 /*
 ** Set the number of backtrace levels kept for each allocation.
 ** A value of zero turns off backtracing.  The number is always rounded
@@ -13457,7 +16051,7 @@ SQLITE_PRIVATE void sqlite3MemdebugSettitle(const char *zTitle){
   if( n>=sizeof(mem.zTitle) ) n = sizeof(mem.zTitle)-1;
   memcpy(mem.zTitle, zTitle, n);
   mem.zTitle[n] = 0;
-  mem.nTitle = (n+7)&~7;
+  mem.nTitle = ROUND8(n);
   sqlite3_mutex_leave(mem.mutex);
 }
 
@@ -13554,8 +16148,6 @@ SQLITE_PRIVATE int sqlite3MemdebugMallocCount(){
 **
 ** This version of the memory allocation subsystem is included
 ** in the build only if SQLITE_ENABLE_MEMSYS3 is defined.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -13966,7 +16558,7 @@ static void *memsys3MallocUnsafe(int nByte){
 ** This function assumes that the necessary mutexes, if any, are
 ** already held by the caller. Hence "Unsafe".
 */
-void memsys3FreeUnsafe(void *pOld){
+static void memsys3FreeUnsafe(void *pOld){
   Mem3Block *p = (Mem3Block*)pOld;
   int i;
   u32 size, x;
@@ -14041,7 +16633,7 @@ static void *memsys3Malloc(int nBytes){
 /*
 ** Free memory.
 */
-void memsys3Free(void *pPrior){
+static void memsys3Free(void *pPrior){
   assert( pPrior );
   memsys3Enter();
   memsys3FreeUnsafe(pPrior);
@@ -14051,7 +16643,7 @@ void memsys3Free(void *pPrior){
 /*
 ** Change the size of an existing memory allocation
 */
-void *memsys3Realloc(void *pPrior, int nBytes){
+static void *memsys3Realloc(void *pPrior, int nBytes){
   int nOld;
   void *p;
   if( pPrior==0 ){
@@ -14109,6 +16701,7 @@ static int memsys3Init(void *NotUsed){
 */
 static void memsys3Shutdown(void *NotUsed){
   UNUSED_PARAMETER(NotUsed);
+  mem3.mutex = 0;
   return;
 }
 
@@ -14235,7 +16828,7 @@ SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void){
 ** allocation subsystem for use by SQLite. 
 **
 ** This version of the memory allocation subsystem omits all
-** use of malloc(). The SQLite user supplies a block of memory
+** use of malloc(). The application gives SQLite a block of memory
 ** before calling sqlite3_initialize() from which allocations
 ** are made and returned by the xMalloc() and xRealloc() 
 ** implementations. Once sqlite3_initialize() has been called,
@@ -14245,7 +16838,30 @@ SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void){
 ** This version of the memory allocation subsystem is included
 ** in the build only if SQLITE_ENABLE_MEMSYS5 is defined.
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+** This memory allocator uses the following algorithm:
+**
+**   1.  All memory allocations sizes are rounded up to a power of 2.
+**
+**   2.  If two adjacent free blocks are the halves of a larger block,
+**       then the two blocks are coalesed into the single larger block.
+**
+**   3.  New memory is allocated from the first available free block.
+**
+** This algorithm is described in: J. M. Robson. "Bounds for Some Functions
+** Concerning Dynamic Storage Allocation". Journal of the Association for
+** Computing Machinery, Volume 21, Number 8, July 1974, pages 491-499.
+** 
+** Let n be the size of the largest allocation divided by the minimum
+** allocation size (after rounding all sizes up to a power of 2.)  Let M
+** be the maximum amount of memory ever outstanding at one time.  Let
+** N be the total amount of memory available for allocation.  Robson
+** proved that this memory allocator will never breakdown due to 
+** fragmentation as long as the following constraint holds:
+**
+**      N >=  M*(1 + log2(n)/2) - n + 1
+**
+** The sqlite3_status() logic tracks the maximum values of n and M so
+** that an application can, at any time, verify this constraint.
 */
 
 /*
@@ -14258,6 +16874,9 @@ SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void){
 ** A minimum allocation is an instance of the following structure.
 ** Larger allocations are an array of these structures where the
 ** size of the array is a power of 2.
+**
+** The size of this object must be a power of two.  That fact is
+** verified in memsys5Init().
 */
 typedef struct Mem5Link Mem5Link;
 struct Mem5Link {
@@ -14266,16 +16885,16 @@ struct Mem5Link {
 };
 
 /*
-** Maximum size of any allocation is ((1<<LOGMAX)*mem5.nAtom). Since
-** mem5.nAtom is always at least 8, this is not really a practical
-** limitation.
+** Maximum size of any allocation is ((1<<LOGMAX)*mem5.szAtom). Since
+** mem5.szAtom is always at least 8 and 32-bit integers are used,
+** it is not actually possible to reach this limit.
 */
 #define LOGMAX 30
 
 /*
 ** Masks used for mem5.aCtrl[] elements.
 */
-#define CTRL_LOGSIZE  0x1f    /* Log2 Size of this block relative to POW2_MIN */
+#define CTRL_LOGSIZE  0x1f    /* Log2 Size of this block */
 #define CTRL_FREE     0x20    /* True if not checked out */
 
 /*
@@ -14288,9 +16907,9 @@ static SQLITE_WSD struct Mem5Global {
   /*
   ** Memory available for allocation
   */
-  int nAtom;       /* Smallest possible allocation in bytes */
-  int nBlock;      /* Number of nAtom sized blocks in zPool */
-  u8 *zPool;
+  int szAtom;      /* Smallest possible allocation in bytes */
+  int nBlock;      /* Number of szAtom sized blocks in zPool */
+  u8 *zPool;       /* Memory available to be allocated */
   
   /*
   ** Mutex to control access to the memory allocation subsystem.
@@ -14310,7 +16929,9 @@ static SQLITE_WSD struct Mem5Global {
   u32 maxRequest;     /* Largest allocation (exclusive of internal frag) */
   
   /*
-  ** Lists of free blocks of various sizes.
+  ** Lists of free blocks.  aiFreelist[0] is a list of free blocks of
+  ** size mem5.szAtom.  aiFreelist[1] holds blocks of size szAtom*2.
+  ** and so forth.
   */
   int aiFreelist[LOGMAX+1];
 
@@ -14320,11 +16941,18 @@ static SQLITE_WSD struct Mem5Global {
   */
   u8 *aCtrl;
 
-} mem5 = { 19804167 };
+} mem5;
 
+/*
+** Access the static variable through a macro for SQLITE_OMIT_WSD
+*/
 #define mem5 GLOBAL(struct Mem5Global, mem5)
 
-#define MEM5LINK(idx) ((Mem5Link *)(&mem5.zPool[(idx)*mem5.nAtom]))
+/*
+** Assuming mem5.zPool is divided up into an array of Mem5Link
+** structures, return a pointer to the idx-th such lik.
+*/
+#define MEM5LINK(idx) ((Mem5Link *)(&mem5.zPool[(idx)*mem5.szAtom]))
 
 /*
 ** Unlink the chunk at mem5.aPool[i] from list it is currently
@@ -14374,9 +17002,6 @@ static void memsys5Link(int i, int iLogsize){
 ** sqlite3GlobalConfig.bMemStat is true.
 */
 static void memsys5Enter(void){
-  if( sqlite3GlobalConfig.bMemstat==0 && mem5.mutex==0 ){
-    mem5.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
-  }
   sqlite3_mutex_enter(mem5.mutex);
 }
 static void memsys5Leave(void){
@@ -14391,9 +17016,9 @@ static void memsys5Leave(void){
 static int memsys5Size(void *p){
   int iSize = 0;
   if( p ){
-    int i = ((u8 *)p-mem5.zPool)/mem5.nAtom;
+    int i = ((u8 *)p-mem5.zPool)/mem5.szAtom;
     assert( i>=0 && i<mem5.nBlock );
-    iSize = mem5.nAtom * (1 << (mem5.aCtrl[i]&CTRL_LOGSIZE));
+    iSize = mem5.szAtom * (1 << (mem5.aCtrl[i]&CTRL_LOGSIZE));
   }
   return iSize;
 }
@@ -14419,7 +17044,13 @@ static int memsys5UnlinkFirst(int iLogsize){
 
 /*
 ** Return a block of memory of at least nBytes in size.
-** Return NULL if unable.
+** Return NULL if unable.  Return NULL if nBytes==0.
+**
+** The caller guarantees that nByte positive.
+**
+** The caller has obtained a mutex prior to invoking this
+** routine so there is never any chance that two or more
+** threads can be in this routine at the same time.
 */
 static void *memsys5MallocUnsafe(int nByte){
   int i;           /* Index of a mem5.aPool[] slot */
@@ -14427,21 +17058,35 @@ static void *memsys5MallocUnsafe(int nByte){
   int iFullSz;     /* Size of allocation rounded up to power of 2 */
   int iLogsize;    /* Log2 of iFullSz/POW2_MIN */
 
+  /* nByte must be a positive */
+  assert( nByte>0 );
+
   /* Keep track of the maximum allocation request.  Even unfulfilled
   ** requests are counted */
   if( (u32)nByte>mem5.maxRequest ){
     mem5.maxRequest = nByte;
   }
 
+  /* Abort if the requested allocation size is larger than the largest
+  ** power of two that we can represent using 32-bit signed integers.
+  */
+  if( nByte > 0x40000000 ){
+    return 0;
+  }
+
   /* Round nByte up to the next valid power of two */
-  for(iFullSz=mem5.nAtom, iLogsize=0; iFullSz<nByte; iFullSz *= 2, iLogsize++){}
+  for(iFullSz=mem5.szAtom, iLogsize=0; iFullSz<nByte; iFullSz *= 2, iLogsize++){}
 
   /* Make sure mem5.aiFreelist[iLogsize] contains at least one free
   ** block.  If not, then split a block of the next larger power of
   ** two in order to create a new free block of size iLogsize.
   */
   for(iBin=iLogsize; mem5.aiFreelist[iBin]<0 && iBin<=LOGMAX; iBin++){}
-  if( iBin>LOGMAX ) return 0;
+  if( iBin>LOGMAX ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes", nByte);
+    return 0;
+  }
   i = memsys5UnlinkFirst(iBin);
   while( iBin>iLogsize ){
     int newSize;
@@ -14463,7 +17108,7 @@ static void *memsys5MallocUnsafe(int nByte){
   if( mem5.maxOut<mem5.currentOut ) mem5.maxOut = mem5.currentOut;
 
   /* Return a pointer to the allocated memory. */
-  return (void*)&mem5.zPool[i*mem5.nAtom];
+  return (void*)&mem5.zPool[i*mem5.szAtom];
 }
 
 /*
@@ -14471,16 +17116,16 @@ static void *memsys5MallocUnsafe(int nByte){
 */
 static void memsys5FreeUnsafe(void *pOld){
   u32 size, iLogsize;
-  int iBlock;             
+  int iBlock;
 
   /* Set iBlock to the index of the block pointed to by pOld in 
-  ** the array of mem5.nAtom byte blocks pointed to by mem5.zPool.
+  ** the array of mem5.szAtom byte blocks pointed to by mem5.zPool.
   */
-  iBlock = ((u8 *)pOld-mem5.zPool)/mem5.nAtom;
+  iBlock = ((u8 *)pOld-mem5.zPool)/mem5.szAtom;
 
   /* Check that the pointer pOld points to a valid, non-free block. */
   assert( iBlock>=0 && iBlock<mem5.nBlock );
-  assert( ((u8 *)pOld-mem5.zPool)%mem5.nAtom==0 );
+  assert( ((u8 *)pOld-mem5.zPool)%mem5.szAtom==0 );
   assert( (mem5.aCtrl[iBlock] & CTRL_FREE)==0 );
 
   iLogsize = mem5.aCtrl[iBlock] & CTRL_LOGSIZE;
@@ -14490,14 +17135,14 @@ static void memsys5FreeUnsafe(void *pOld){
   mem5.aCtrl[iBlock] |= CTRL_FREE;
   mem5.aCtrl[iBlock+size-1] |= CTRL_FREE;
   assert( mem5.currentCount>0 );
-  assert( mem5.currentOut>=(size*mem5.nAtom) );
+  assert( mem5.currentOut>=(size*mem5.szAtom) );
   mem5.currentCount--;
-  mem5.currentOut -= size*mem5.nAtom;
+  mem5.currentOut -= size*mem5.szAtom;
   assert( mem5.currentOut>0 || mem5.currentCount==0 );
   assert( mem5.currentCount>0 || mem5.currentOut==0 );
 
   mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize;
-  while( iLogsize<LOGMAX ){
+  while( ALWAYS(iLogsize<LOGMAX) ){
     int iBuddy;
     if( (iBlock>>iLogsize) & 1 ){
       iBuddy = iBlock - size;
@@ -14537,28 +17182,36 @@ static void *memsys5Malloc(int nBytes){
 
 /*
 ** Free memory.
+**
+** The outer layer memory allocator prevents this routine from
+** being called with pPrior==0.
 */
 static void memsys5Free(void *pPrior){
-  if( pPrior==0 ){
-assert(0);
-    return;
-  }
+  assert( pPrior!=0 );
   memsys5Enter();
   memsys5FreeUnsafe(pPrior);
   memsys5Leave();  
 }
 
 /*
-** Change the size of an existing memory allocation
+** Change the size of an existing memory allocation.
+**
+** The outer layer memory allocator prevents this routine from
+** being called with pPrior==0.  
+**
+** nBytes is always a value obtained from a prior call to
+** memsys5Round().  Hence nBytes is always a non-negative power
+** of two.  If nBytes==0 that means that an oversize allocation
+** (an allocation larger than 0x40000000) was requested and this
+** routine should return 0 without freeing pPrior.
 */
 static void *memsys5Realloc(void *pPrior, int nBytes){
   int nOld;
   void *p;
-  if( pPrior==0 ){
-    return memsys5Malloc(nBytes);
-  }
-  if( nBytes<=0 ){
-    memsys5Free(pPrior);
+  assert( pPrior!=0 );
+  assert( (nBytes&(nBytes-1))==0 );  /* EV: R-46199-30249 */
+  assert( nBytes>=0 );
+  if( nBytes==0 ){
     return 0;
   }
   nOld = memsys5Size(pPrior);
@@ -14576,45 +17229,74 @@ static void *memsys5Realloc(void *pPrior, int nBytes){
 }
 
 /*
-** Round up a request size to the next valid allocation size.
+** Round up a request size to the next valid allocation size.  If
+** the allocation is too large to be handled by this allocation system,
+** return 0.
+**
+** All allocations must be a power of two and must be expressed by a
+** 32-bit signed integer.  Hence the largest allocation is 0x40000000
+** or 1073741824 bytes.
 */
 static int memsys5Roundup(int n){
   int iFullSz;
-  for(iFullSz=mem5.nAtom; iFullSz<n; iFullSz *= 2);
+  if( n > 0x40000000 ) return 0;
+  for(iFullSz=mem5.szAtom; iFullSz<n; iFullSz *= 2);
   return iFullSz;
 }
 
+/*
+** Return the ceiling of the logarithm base 2 of iValue.
+**
+** Examples:   memsys5Log(1) -> 0
+**             memsys5Log(2) -> 1
+**             memsys5Log(4) -> 2
+**             memsys5Log(5) -> 3
+**             memsys5Log(8) -> 3
+**             memsys5Log(9) -> 4
+*/
 static int memsys5Log(int iValue){
   int iLog;
-  for(iLog=0; (1<<iLog)<iValue; iLog++);
+  for(iLog=0; (iLog<(int)((sizeof(int)*8)-1)) && (1<<iLog)<iValue; iLog++);
   return iLog;
 }
 
 /*
-** Initialize this module.
+** Initialize the memory allocator.
+**
+** This routine is not threadsafe.  The caller must be holding a mutex
+** to prevent multiple threads from entering at the same time.
 */
 static int memsys5Init(void *NotUsed){
-  int ii;
-  int nByte = sqlite3GlobalConfig.nHeap;
-  u8 *zByte = (u8 *)sqlite3GlobalConfig.pHeap;
-  int nMinLog;                 /* Log of minimum allocation size in bytes*/
-  int iOffset;
+  int ii;            /* Loop counter */
+  int nByte;         /* Number of bytes of memory available to this allocator */
+  u8 *zByte;         /* Memory usable by this allocator */
+  int nMinLog;       /* Log base 2 of minimum allocation size in bytes */
+  int iOffset;       /* An offset into mem5.aCtrl[] */
 
   UNUSED_PARAMETER(NotUsed);
 
-  if( !zByte ){
-    return SQLITE_ERROR;
-  }
+  /* For the purposes of this routine, disable the mutex */
+  mem5.mutex = 0;
 
+  /* The size of a Mem5Link object must be a power of two.  Verify that
+  ** this is case.
+  */
+  assert( (sizeof(Mem5Link)&(sizeof(Mem5Link)-1))==0 );
+
+  nByte = sqlite3GlobalConfig.nHeap;
+  zByte = (u8*)sqlite3GlobalConfig.pHeap;
+  assert( zByte!=0 );  /* sqlite3_config() does not allow otherwise */
+
+  /* boundaries on sqlite3GlobalConfig.mnReq are enforced in sqlite3_config() */
   nMinLog = memsys5Log(sqlite3GlobalConfig.mnReq);
-  mem5.nAtom = (1<<nMinLog);
-  while( (int)sizeof(Mem5Link)>mem5.nAtom ){
-    mem5.nAtom = mem5.nAtom << 1;
+  mem5.szAtom = (1<<nMinLog);
+  while( (int)sizeof(Mem5Link)>mem5.szAtom ){
+    mem5.szAtom = mem5.szAtom << 1;
   }
 
-  mem5.nBlock = (nByte / (mem5.nAtom+sizeof(u8)));
+  mem5.nBlock = (nByte / (mem5.szAtom+sizeof(u8)));
   mem5.zPool = zByte;
-  mem5.aCtrl = (u8 *)&mem5.zPool[mem5.nBlock*mem5.nAtom];
+  mem5.aCtrl = (u8 *)&mem5.zPool[mem5.nBlock*mem5.szAtom];
 
   for(ii=0; ii<=LOGMAX; ii++){
     mem5.aiFreelist[ii] = -1;
@@ -14631,6 +17313,11 @@ static int memsys5Init(void *NotUsed){
     assert((iOffset+nAlloc)>mem5.nBlock);
   }
 
+  /* If a mutex is required for normal operation, allocate one */
+  if( sqlite3GlobalConfig.bMemstat==0 ){
+    mem5.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+
   return SQLITE_OK;
 }
 
@@ -14639,15 +17326,16 @@ static int memsys5Init(void *NotUsed){
 */
 static void memsys5Shutdown(void *NotUsed){
   UNUSED_PARAMETER(NotUsed);
+  mem5.mutex = 0;
   return;
 }
 
+#ifdef SQLITE_TEST
 /*
 ** Open the file indicated and write a log of all unfreed memory 
 ** allocations into that log.
 */
 SQLITE_PRIVATE void sqlite3Memsys5Dump(const char *zFilename){
-#ifdef SQLITE_DEBUG
   FILE *out;
   int i, j, n;
   int nMinLog;
@@ -14663,10 +17351,10 @@ SQLITE_PRIVATE void sqlite3Memsys5Dump(const char *zFilename){
     }
   }
   memsys5Enter();
-  nMinLog = memsys5Log(mem5.nAtom);
+  nMinLog = memsys5Log(mem5.szAtom);
   for(i=0; i<=LOGMAX && i+nMinLog<32; i++){
     for(n=0, j=mem5.aiFreelist[i]; j>=0; j = MEM5LINK(j)->next, n++){}
-    fprintf(out, "freelist items of size %d: %d\n", mem5.nAtom << i, n);
+    fprintf(out, "freelist items of size %d: %d\n", mem5.szAtom << i, n);
   }
   fprintf(out, "mem5.nAlloc       = %llu\n", mem5.nAlloc);
   fprintf(out, "mem5.totalAlloc   = %llu\n", mem5.totalAlloc);
@@ -14682,10 +17370,8 @@ SQLITE_PRIVATE void sqlite3Memsys5Dump(const char *zFilename){
   }else{
     fclose(out);
   }
-#else
-  UNUSED_PARAMETER(zFilename);
-#endif
 }
+#endif
 
 /*
 ** This routine is the only routine in this file with external 
@@ -14724,50 +17410,48 @@ SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys5(void){
 ** This file contains the C functions that implement mutexes.
 **
 ** This file contains code that is common across all mutex implementations.
-
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_MUTEX_OMIT)
+/*
+** For debugging purposes, record when the mutex subsystem is initialized
+** and uninitialized so that we can assert() if there is an attempt to
+** allocate a mutex while the system is uninitialized.
+*/
+static SQLITE_WSD int mutexIsInit = 0;
+#endif /* SQLITE_DEBUG */
+
+
 #ifndef SQLITE_MUTEX_OMIT
 /*
 ** Initialize the mutex system.
 */
 SQLITE_PRIVATE int sqlite3MutexInit(void){ 
   int rc = SQLITE_OK;
-  if( sqlite3GlobalConfig.bCoreMutex ){
-    if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){
-      /* If the xMutexAlloc method has not been set, then the user did not
-      ** install a mutex implementation via sqlite3_config() prior to 
-      ** sqlite3_initialize() being called. This block copies pointers to
-      ** the default implementation into the sqlite3GlobalConfig structure.
-      **
-      ** The danger is that although sqlite3_config() is not a threadsafe
-      ** API, sqlite3_initialize() is, and so multiple threads may be
-      ** attempting to run this function simultaneously. To guard write
-      ** access to the sqlite3GlobalConfig structure, the 'MASTER' static mutex
-      ** is obtained before modifying it.
-      */
-      sqlite3_mutex_methods *p = sqlite3DefaultMutex();
-      sqlite3_mutex *pMaster = 0;
-  
-      rc = p->xMutexInit();
-      if( rc==SQLITE_OK ){
-        pMaster = p->xMutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
-        assert(pMaster);
-        p->xMutexEnter(pMaster);
-        assert( sqlite3GlobalConfig.mutex.xMutexAlloc==0 
-             || sqlite3GlobalConfig.mutex.xMutexAlloc==p->xMutexAlloc
-        );
-        if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){
-          sqlite3GlobalConfig.mutex = *p;
-        }
-        p->xMutexLeave(pMaster);
-      }
+  if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){
+    /* If the xMutexAlloc method has not been set, then the user did not
+    ** install a mutex implementation via sqlite3_config() prior to 
+    ** sqlite3_initialize() being called. This block copies pointers to
+    ** the default implementation into the sqlite3GlobalConfig structure.
+    */
+    sqlite3_mutex_methods const *pFrom;
+    sqlite3_mutex_methods *pTo = &sqlite3GlobalConfig.mutex;
+
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pFrom = sqlite3DefaultMutex();
     }else{
-      rc = sqlite3GlobalConfig.mutex.xMutexInit();
+      pFrom = sqlite3NoopMutex();
     }
+    memcpy(pTo, pFrom, offsetof(sqlite3_mutex_methods, xMutexAlloc));
+    memcpy(&pTo->xMutexFree, &pFrom->xMutexFree,
+           sizeof(*pTo) - offsetof(sqlite3_mutex_methods, xMutexFree));
+    pTo->xMutexAlloc = pFrom->xMutexAlloc;
   }
+  rc = sqlite3GlobalConfig.mutex.xMutexInit();
+
+#ifdef SQLITE_DEBUG
+  GLOBAL(int, mutexIsInit) = 1;
+#endif
 
   return rc;
 }
@@ -14778,7 +17462,14 @@ SQLITE_PRIVATE int sqlite3MutexInit(void){
 */
 SQLITE_PRIVATE int sqlite3MutexEnd(void){
   int rc = SQLITE_OK;
-  rc = sqlite3GlobalConfig.mutex.xMutexEnd();
+  if( sqlite3GlobalConfig.mutex.xMutexEnd ){
+    rc = sqlite3GlobalConfig.mutex.xMutexEnd();
+  }
+
+#ifdef SQLITE_DEBUG
+  GLOBAL(int, mutexIsInit) = 0;
+#endif
+
   return rc;
 }
 
@@ -14796,6 +17487,7 @@ SQLITE_PRIVATE sqlite3_mutex *sqlite3MutexAlloc(int id){
   if( !sqlite3GlobalConfig.bCoreMutex ){
     return 0;
   }
+  assert( GLOBAL(int, mutexIsInit) );
   return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
 }
 
@@ -14855,7 +17547,7 @@ SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
 }
 #endif
 
-#endif /* SQLITE_OMIT_MUTEX */
+#endif /* !defined(SQLITE_MUTEX_OMIT) */
 
 /************** End of mutex.c ***********************************************/
 /************** Begin file mutex_noop.c **************************************/
@@ -14885,29 +17577,32 @@ SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
 ** If compiled with SQLITE_DEBUG, then additional logic is inserted
 ** that does error checking on mutexes to make sure they are being
 ** called correctly.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
+#ifndef SQLITE_MUTEX_OMIT
 
-#if defined(SQLITE_MUTEX_NOOP) && !defined(SQLITE_DEBUG)
+#ifndef SQLITE_DEBUG
 /*
 ** Stub routines for all mutex methods.
 **
 ** This routines provide no mutual exclusion or error checking.
 */
-static int noopMutexHeld(sqlite3_mutex *p){ return 1; }
-static int noopMutexNotheld(sqlite3_mutex *p){ return 1; }
 static int noopMutexInit(void){ return SQLITE_OK; }
 static int noopMutexEnd(void){ return SQLITE_OK; }
-static sqlite3_mutex *noopMutexAlloc(int id){ return (sqlite3_mutex*)8; }
-static void noopMutexFree(sqlite3_mutex *p){ return; }
-static void noopMutexEnter(sqlite3_mutex *p){ return; }
-static int noopMutexTry(sqlite3_mutex *p){ return SQLITE_OK; }
-static void noopMutexLeave(sqlite3_mutex *p){ return; }
+static sqlite3_mutex *noopMutexAlloc(int id){ 
+  UNUSED_PARAMETER(id);
+  return (sqlite3_mutex*)8; 
+}
+static void noopMutexFree(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+static void noopMutexEnter(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+static int noopMutexTry(sqlite3_mutex *p){
+  UNUSED_PARAMETER(p);
+  return SQLITE_OK;
+}
+static void noopMutexLeave(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
 
-SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
-  static sqlite3_mutex_methods sMutex = {
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
     noopMutexInit,
     noopMutexEnd,
     noopMutexAlloc,
@@ -14916,15 +17611,15 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
     noopMutexTry,
     noopMutexLeave,
 
-    noopMutexHeld,
-    noopMutexNotheld
+    0,
+    0,
   };
 
   return &sMutex;
 }
-#endif /* defined(SQLITE_MUTEX_NOOP) && !defined(SQLITE_DEBUG) */
+#endif /* !SQLITE_DEBUG */
 
-#if defined(SQLITE_MUTEX_NOOP) && defined(SQLITE_DEBUG)
+#ifdef SQLITE_DEBUG
 /*
 ** In this implementation, error checking is provided for testing
 ** and debugging purposes.  The mutexes still do not provide any
@@ -14934,19 +17629,21 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
 /*
 ** The mutex object
 */
-struct sqlite3_mutex {
+typedef struct sqlite3_debug_mutex {
   int id;     /* The mutex type */
   int cnt;    /* Number of entries without a matching leave */
-};
+} sqlite3_debug_mutex;
 
 /*
 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
 ** intended for use inside assert() statements.
 */
-static int debugMutexHeld(sqlite3_mutex *p){
+static int debugMutexHeld(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
   return p==0 || p->cnt>0;
 }
-static int debugMutexNotheld(sqlite3_mutex *p){
+static int debugMutexNotheld(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
   return p==0 || p->cnt==0;
 }
 
@@ -14962,8 +17659,8 @@ static int debugMutexEnd(void){ return SQLITE_OK; }
 ** that means that a mutex could not be allocated. 
 */
 static sqlite3_mutex *debugMutexAlloc(int id){
-  static sqlite3_mutex aStatic[6];
-  sqlite3_mutex *pNew = 0;
+  static sqlite3_debug_mutex aStatic[6];
+  sqlite3_debug_mutex *pNew = 0;
   switch( id ){
     case SQLITE_MUTEX_FAST:
     case SQLITE_MUTEX_RECURSIVE: {
@@ -14982,13 +17679,14 @@ static sqlite3_mutex *debugMutexAlloc(int id){
       break;
     }
   }
-  return pNew;
+  return (sqlite3_mutex*)pNew;
 }
 
 /*
 ** This routine deallocates a previously allocated mutex.
 */
-static void debugMutexFree(sqlite3_mutex *p){
+static void debugMutexFree(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
   assert( p->cnt==0 );
   assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
   sqlite3_free(p);
@@ -15005,12 +17703,14 @@ static void debugMutexFree(sqlite3_mutex *p){
 ** can enter.  If the same thread tries to enter any other kind of mutex
 ** more than once, the behavior is undefined.
 */
-static void debugMutexEnter(sqlite3_mutex *p){
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(p) );
+static void debugMutexEnter(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
   p->cnt++;
 }
-static int debugMutexTry(sqlite3_mutex *p){
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(p) );
+static int debugMutexTry(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
   p->cnt++;
   return SQLITE_OK;
 }
@@ -15021,14 +17721,15 @@ static int debugMutexTry(sqlite3_mutex *p){
 ** is undefined if the mutex is not currently entered or
 ** is not currently allocated.  SQLite will never do either.
 */
-static void debugMutexLeave(sqlite3_mutex *p){
-  assert( debugMutexHeld(p) );
+static void debugMutexLeave(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( debugMutexHeld(pX) );
   p->cnt--;
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(p) );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
 }
 
-SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
-  static sqlite3_mutex_methods sMutex = {
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
     debugMutexInit,
     debugMutexEnd,
     debugMutexAlloc,
@@ -15043,284 +17744,20 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
 
   return &sMutex;
 }
-#endif /* defined(SQLITE_MUTEX_NOOP) && defined(SQLITE_DEBUG) */
+#endif /* SQLITE_DEBUG */
+
+/*
+** If compiled with SQLITE_MUTEX_NOOP, then the no-op mutex implementation
+** is used regardless of the run-time threadsafety setting.
+*/
+#ifdef SQLITE_MUTEX_NOOP
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  return sqlite3NoopMutex();
+}
+#endif /* defined(SQLITE_MUTEX_NOOP) */
+#endif /* !defined(SQLITE_MUTEX_OMIT) */
 
 /************** End of mutex_noop.c ******************************************/
-/************** Begin file mutex_os2.c ***************************************/
-/*
-** 2007 August 28
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-*************************************************************************
-** This file contains the C functions that implement mutexes for OS/2
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-*/
-
-/*
-** The code in this file is only used if SQLITE_MUTEX_OS2 is defined.
-** See the mutex.h file for details.
-*/
-#ifdef SQLITE_MUTEX_OS2
-
-/********************** OS/2 Mutex Implementation **********************
-**
-** This implementation of mutexes is built using the OS/2 API.
-*/
-
-/*
-** The mutex object
-** Each recursive mutex is an instance of the following structure.
-*/
-struct sqlite3_mutex {
-  HMTX mutex;       /* Mutex controlling the lock */
-  int  id;          /* Mutex type */
-  int  nRef;        /* Number of references */
-  TID  owner;       /* Thread holding this mutex */
-};
-
-#define OS2_MUTEX_INITIALIZER   0,0,0,0
-
-/*
-** Initialize and deinitialize the mutex subsystem.
-*/
-static int os2MutexInit(void){ return SQLITE_OK; }
-static int os2MutexEnd(void){ return SQLITE_OK; }
-
-/*
-** The sqlite3_mutex_alloc() routine allocates a new
-** mutex and returns a pointer to it.  If it returns NULL
-** that means that a mutex could not be allocated. 
-** SQLite will unwind its stack and return an error.  The argument
-** to sqlite3_mutex_alloc() is one of these integer constants:
-**
-** <ul>
-** <li>  SQLITE_MUTEX_FAST               0
-** <li>  SQLITE_MUTEX_RECURSIVE          1
-** <li>  SQLITE_MUTEX_STATIC_MASTER      2
-** <li>  SQLITE_MUTEX_STATIC_MEM         3
-** <li>  SQLITE_MUTEX_STATIC_PRNG        4
-** </ul>
-**
-** The first two constants cause sqlite3_mutex_alloc() to create
-** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
-** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
-** The mutex implementation does not need to make a distinction
-** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
-** not want to.  But SQLite will only request a recursive mutex in
-** cases where it really needs one.  If a faster non-recursive mutex
-** implementation is available on the host platform, the mutex subsystem
-** might return such a mutex in response to SQLITE_MUTEX_FAST.
-**
-** The other allowed parameters to sqlite3_mutex_alloc() each return
-** a pointer to a static preexisting mutex.  Three static mutexes are
-** used by the current version of SQLite.  Future versions of SQLite
-** may add additional static mutexes.  Static mutexes are for internal
-** use by SQLite only.  Applications that use SQLite mutexes should
-** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
-** SQLITE_MUTEX_RECURSIVE.
-**
-** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
-** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
-** returns a different mutex on every call.  But for the static
-** mutex types, the same mutex is returned on every call that has
-** the same type number.
-*/
-static sqlite3_mutex *os2MutexAlloc(int iType){
-  sqlite3_mutex *p = NULL;
-  switch( iType ){
-    case SQLITE_MUTEX_FAST:
-    case SQLITE_MUTEX_RECURSIVE: {
-      p = sqlite3MallocZero( sizeof(*p) );
-      if( p ){
-        p->id = iType;
-        if( DosCreateMutexSem( 0, &p->mutex, 0, FALSE ) != NO_ERROR ){
-          sqlite3_free( p );
-          p = NULL;
-        }
-      }
-      break;
-    }
-    default: {
-      static volatile int isInit = 0;
-      static sqlite3_mutex staticMutexes[] = {
-        { OS2_MUTEX_INITIALIZER, },
-        { OS2_MUTEX_INITIALIZER, },
-        { OS2_MUTEX_INITIALIZER, },
-        { OS2_MUTEX_INITIALIZER, },
-        { OS2_MUTEX_INITIALIZER, },
-        { OS2_MUTEX_INITIALIZER, },
-      };
-      if ( !isInit ){
-        APIRET rc;
-        PTIB ptib;
-        PPIB ppib;
-        HMTX mutex;
-        char name[32];
-        DosGetInfoBlocks( &ptib, &ppib );
-        sqlite3_snprintf( sizeof(name), name, "\\SEM32\\SQLITE%04x",
-                          ppib->pib_ulpid );
-        while( !isInit ){
-          mutex = 0;
-          rc = DosCreateMutexSem( name, &mutex, 0, FALSE);
-          if( rc == NO_ERROR ){
-            unsigned int i;
-            if( !isInit ){
-              for( i = 0; i < sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++ ){
-                DosCreateMutexSem( 0, &staticMutexes[i].mutex, 0, FALSE );
-              }
-              isInit = 1;
-            }
-            DosCloseMutexSem( mutex );
-          }else if( rc == ERROR_DUPLICATE_NAME ){
-            DosSleep( 1 );
-          }else{
-            return p;
-          }
-        }
-      }
-      assert( iType-2 >= 0 );
-      assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) );
-      p = &staticMutexes[iType-2];
-      p->id = iType;
-      break;
-    }
-  }
-  return p;
-}
-
-
-/*
-** This routine deallocates a previously allocated mutex.
-** SQLite is careful to deallocate every mutex that it allocates.
-*/
-static void os2MutexFree(sqlite3_mutex *p){
-  if( p==0 ) return;
-  assert( p->nRef==0 );
-  assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
-  DosCloseMutexSem( p->mutex );
-  sqlite3_free( p );
-}
-
-/*
-** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
-** to enter a mutex.  If another thread is already within the mutex,
-** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
-** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
-** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
-** be entered multiple times by the same thread.  In such cases the,
-** mutex must be exited an equal number of times before another thread
-** can enter.  If the same thread tries to enter any other kind of mutex
-** more than once, the behavior is undefined.
-*/
-static void os2MutexEnter(sqlite3_mutex *p){
-  TID tid;
-  PID holder1;
-  ULONG holder2;
-  if( p==0 ) return;
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || os2MutexNotheld(p) );
-  DosRequestMutexSem(p->mutex, SEM_INDEFINITE_WAIT);
-  DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2);
-  p->owner = tid;
-  p->nRef++;
-}
-static int os2MutexTry(sqlite3_mutex *p){
-  int rc;
-  TID tid;
-  PID holder1;
-  ULONG holder2;
-  if( p==0 ) return SQLITE_OK;
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || os2MutexNotheld(p) );
-  if( DosRequestMutexSem(p->mutex, SEM_IMMEDIATE_RETURN) == NO_ERROR) {
-    DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2);
-    p->owner = tid;
-    p->nRef++;
-    rc = SQLITE_OK;
-  } else {
-    rc = SQLITE_BUSY;
-  }
-
-  return rc;
-}
-
-/*
-** The sqlite3_mutex_leave() routine exits a mutex that was
-** previously entered by the same thread.  The behavior
-** is undefined if the mutex is not currently entered or
-** is not currently allocated.  SQLite will never do either.
-*/
-static void os2MutexLeave(sqlite3_mutex *p){
-  TID tid;
-  PID holder1;
-  ULONG holder2;
-  if( p==0 ) return;
-  assert( p->nRef>0 );
-  DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2);
-  assert( p->owner==tid );
-  p->nRef--;
-  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
-  DosReleaseMutexSem(p->mutex);
-}
-
-#ifdef SQLITE_DEBUG
-/*
-** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
-** intended for use inside assert() statements.
-*/
-static int os2MutexHeld(sqlite3_mutex *p){
-  TID tid;
-  PID pid;
-  ULONG ulCount;
-  PTIB ptib;
-  if( p!=0 ) {
-    DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
-  } else {
-    DosGetInfoBlocks(&ptib, NULL);
-    tid = ptib->tib_ptib2->tib2_ultid;
-  }
-  return p==0 || (p->nRef!=0 && p->owner==tid);
-}
-static int os2MutexNotheld(sqlite3_mutex *p){
-  TID tid;
-  PID pid;
-  ULONG ulCount;
-  PTIB ptib;
-  if( p!= 0 ) {
-    DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount);
-  } else {
-    DosGetInfoBlocks(&ptib, NULL);
-    tid = ptib->tib_ptib2->tib2_ultid;
-  }
-  return p==0 || p->nRef==0 || p->owner!=tid;
-}
-#endif
-
-SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
-  static sqlite3_mutex_methods sMutex = {
-    os2MutexInit,
-    os2MutexEnd,
-    os2MutexAlloc,
-    os2MutexFree,
-    os2MutexEnter,
-    os2MutexTry,
-    os2MutexLeave,
-#ifdef SQLITE_DEBUG
-    os2MutexHeld,
-    os2MutexNotheld
-#endif
-  };
-
-  return &sMutex;
-}
-#endif /* SQLITE_MUTEX_OS2 */
-
-/************** End of mutex_os2.c *******************************************/
 /************** Begin file mutex_unix.c **************************************/
 /*
 ** 2007 August 28
@@ -15334,8 +17771,6 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
 **
 *************************************************************************
 ** This file contains the C functions that implement mutexes for pthreads
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -15349,23 +17784,33 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
 
 #include <pthread.h>
 
+/*
+** The sqlite3_mutex.id, sqlite3_mutex.nRef, and sqlite3_mutex.owner fields
+** are necessary under two condidtions:  (1) Debug builds and (2) using
+** home-grown mutexes.  Encapsulate these conditions into a single #define.
+*/
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HOMEGROWN_RECURSIVE_MUTEX)
+# define SQLITE_MUTEX_NREF 1
+#else
+# define SQLITE_MUTEX_NREF 0
+#endif
 
 /*
 ** Each recursive mutex is an instance of the following structure.
 */
 struct sqlite3_mutex {
   pthread_mutex_t mutex;     /* Mutex controlling the lock */
+#if SQLITE_MUTEX_NREF
   int id;                    /* Mutex type */
-  int nRef;                  /* Number of entrances */
-  pthread_t owner;           /* Thread that is within this mutex */
-#ifdef SQLITE_DEBUG
+  volatile int nRef;         /* Number of entrances */
+  volatile pthread_t owner;  /* Thread that is within this mutex */
   int trace;                 /* True to trace changes */
 #endif
 };
-#ifdef SQLITE_DEBUG
+#if SQLITE_MUTEX_NREF
 #define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0, 0 }
 #else
-#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0 }
+#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER }
 #endif
 
 /*
@@ -15414,6 +17859,7 @@ static int pthreadMutexEnd(void){ return SQLITE_OK; }
 ** <li>  SQLITE_MUTEX_STATIC_MEM2
 ** <li>  SQLITE_MUTEX_STATIC_PRNG
 ** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
 ** </ul>
 **
 ** The first two constants cause sqlite3_mutex_alloc() to create
@@ -15427,7 +17873,7 @@ static int pthreadMutexEnd(void){ return SQLITE_OK; }
 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
 **
 ** The other allowed parameters to sqlite3_mutex_alloc() each return
-** a pointer to a static preexisting mutex.  Three static mutexes are
+** a pointer to a static preexisting mutex.  Six static mutexes are
 ** used by the current version of SQLite.  Future versions of SQLite
 ** may add additional static mutexes.  Static mutexes are for internal
 ** use by SQLite only.  Applications that use SQLite mutexes should
@@ -15466,14 +17912,18 @@ static sqlite3_mutex *pthreadMutexAlloc(int iType){
         pthread_mutex_init(&p->mutex, &recursiveAttr);
         pthread_mutexattr_destroy(&recursiveAttr);
 #endif
+#if SQLITE_MUTEX_NREF
         p->id = iType;
+#endif
       }
       break;
     }
     case SQLITE_MUTEX_FAST: {
       p = sqlite3MallocZero( sizeof(*p) );
       if( p ){
+#if SQLITE_MUTEX_NREF
         p->id = iType;
+#endif
         pthread_mutex_init(&p->mutex, 0);
       }
       break;
@@ -15482,7 +17932,9 @@ static sqlite3_mutex *pthreadMutexAlloc(int iType){
       assert( iType-2 >= 0 );
       assert( iType-2 < ArraySize(staticMutexes) );
       p = &staticMutexes[iType-2];
+#if SQLITE_MUTEX_NREF
       p->id = iType;
+#endif
       break;
     }
   }
@@ -15542,9 +17994,12 @@ static void pthreadMutexEnter(sqlite3_mutex *p){
   /* Use the built-in recursive mutexes if they are available.
   */
   pthread_mutex_lock(&p->mutex);
+#if SQLITE_MUTEX_NREF
+  assert( p->nRef>0 || p->owner==0 );
   p->owner = pthread_self();
   p->nRef++;
 #endif
+#endif
 
 #ifdef SQLITE_DEBUG
   if( p->trace ){
@@ -15585,8 +18040,10 @@ static int pthreadMutexTry(sqlite3_mutex *p){
   /* Use the built-in recursive mutexes if they are available.
   */
   if( pthread_mutex_trylock(&p->mutex)==0 ){
+#if SQLITE_MUTEX_NREF
     p->owner = pthread_self();
     p->nRef++;
+#endif
     rc = SQLITE_OK;
   }else{
     rc = SQLITE_BUSY;
@@ -15609,7 +18066,10 @@ static int pthreadMutexTry(sqlite3_mutex *p){
 */
 static void pthreadMutexLeave(sqlite3_mutex *p){
   assert( pthreadMutexHeld(p) );
+#if SQLITE_MUTEX_NREF
   p->nRef--;
+  if( p->nRef==0 ) p->owner = 0;
+#endif
   assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
 
 #ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
@@ -15627,8 +18087,8 @@ static void pthreadMutexLeave(sqlite3_mutex *p){
 #endif
 }
 
-SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
-  static sqlite3_mutex_methods sMutex = {
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
     pthreadMutexInit,
     pthreadMutexEnd,
     pthreadMutexAlloc,
@@ -15648,7 +18108,7 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
   return &sMutex;
 }
 
-#endif /* SQLITE_MUTEX_PTHREAD */
+#endif /* SQLITE_MUTEX_PTHREADS */
 
 /************** End of mutex_unix.c ******************************************/
 /************** Begin file mutex_w32.c ***************************************/
@@ -15664,8 +18124,6 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
 **
 *************************************************************************
 ** This file contains the C functions that implement mutexes for win32
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -15680,9 +18138,18 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
 struct sqlite3_mutex {
   CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
   int id;                    /* Mutex type */
-  int nRef;                  /* Number of enterances */
-  DWORD owner;               /* Thread holding this mutex */
+#ifdef SQLITE_DEBUG
+  volatile int nRef;         /* Number of enterances */
+  volatile DWORD owner;      /* Thread holding this mutex */
+  int trace;                 /* True to trace changes */
+#endif
 };
+#define SQLITE_W32_MUTEX_INITIALIZER { 0 }
+#ifdef SQLITE_DEBUG
+#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0, 0L, (DWORD)0, 0 }
+#else
+#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0 }
+#endif
 
 /*
 ** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
@@ -15702,7 +18169,7 @@ struct sqlite3_mutex {
 ** this out as well.
 */
 #if 0
-#if SQLITE_OS_WINCE
+#if SQLITE_OS_WINCE || SQLITE_OS_WINRT
 # define mutexIsNT()  (1)
 #else
   static int mutexIsNT(void){
@@ -15726,8 +18193,12 @@ struct sqlite3_mutex {
 static int winMutexHeld(sqlite3_mutex *p){
   return p->nRef!=0 && p->owner==GetCurrentThreadId();
 }
+static int winMutexNotheld2(sqlite3_mutex *p, DWORD tid){
+  return p->nRef==0 || p->owner!=tid;
+}
 static int winMutexNotheld(sqlite3_mutex *p){
-  return p->nRef==0 || p->owner!=GetCurrentThreadId();
+  DWORD tid = GetCurrentThreadId(); 
+  return winMutexNotheld2(p, tid);
 }
 #endif
 
@@ -15735,8 +18206,59 @@ static int winMutexNotheld(sqlite3_mutex *p){
 /*
 ** Initialize and deinitialize the mutex subsystem.
 */
-static int winMutexInit(void){ return SQLITE_OK; }
-static int winMutexEnd(void){ return SQLITE_OK; }
+static sqlite3_mutex winMutex_staticMutexes[6] = {
+  SQLITE3_MUTEX_INITIALIZER,
+  SQLITE3_MUTEX_INITIALIZER,
+  SQLITE3_MUTEX_INITIALIZER,
+  SQLITE3_MUTEX_INITIALIZER,
+  SQLITE3_MUTEX_INITIALIZER,
+  SQLITE3_MUTEX_INITIALIZER
+};
+static int winMutex_isInit = 0;
+/* As winMutexInit() and winMutexEnd() are called as part
+** of the sqlite3_initialize and sqlite3_shutdown()
+** processing, the "interlocked" magic is probably not
+** strictly necessary.
+*/
+static long winMutex_lock = 0;
+
+SQLITE_API void sqlite3_win32_sleep(DWORD milliseconds); /* os_win.c */
+
+static int winMutexInit(void){ 
+  /* The first to increment to 1 does actual initialization */
+  if( InterlockedCompareExchange(&winMutex_lock, 1, 0)==0 ){
+    int i;
+    for(i=0; i<ArraySize(winMutex_staticMutexes); i++){
+#if SQLITE_OS_WINRT
+      InitializeCriticalSectionEx(&winMutex_staticMutexes[i].mutex, 0, 0);
+#else
+      InitializeCriticalSection(&winMutex_staticMutexes[i].mutex);
+#endif
+    }
+    winMutex_isInit = 1;
+  }else{
+    /* Someone else is in the process of initing the static mutexes */
+    while( !winMutex_isInit ){
+      sqlite3_win32_sleep(1);
+    }
+  }
+  return SQLITE_OK; 
+}
+
+static int winMutexEnd(void){ 
+  /* The first to decrement to 0 does actual shutdown 
+  ** (which should be the last to shutdown.) */
+  if( InterlockedCompareExchange(&winMutex_lock, 0, 1)==1 ){
+    if( winMutex_isInit==1 ){
+      int i;
+      for(i=0; i<ArraySize(winMutex_staticMutexes); i++){
+        DeleteCriticalSection(&winMutex_staticMutexes[i].mutex);
+      }
+      winMutex_isInit = 0;
+    }
+  }
+  return SQLITE_OK; 
+}
 
 /*
 ** The sqlite3_mutex_alloc() routine allocates a new
@@ -15746,11 +18268,14 @@ static int winMutexEnd(void){ return SQLITE_OK; }
 ** to sqlite3_mutex_alloc() is one of these integer constants:
 **
 ** <ul>
-** <li>  SQLITE_MUTEX_FAST               0
-** <li>  SQLITE_MUTEX_RECURSIVE          1
-** <li>  SQLITE_MUTEX_STATIC_MASTER      2
-** <li>  SQLITE_MUTEX_STATIC_MEM         3
-** <li>  SQLITE_MUTEX_STATIC_PRNG        4
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MASTER
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_MEM2
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
 ** </ul>
 **
 ** The first two constants cause sqlite3_mutex_alloc() to create
@@ -15764,7 +18289,7 @@ static int winMutexEnd(void){ return SQLITE_OK; }
 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
 **
 ** The other allowed parameters to sqlite3_mutex_alloc() each return
-** a pointer to a static preexisting mutex.  Three static mutexes are
+** a pointer to a static preexisting mutex.  Six static mutexes are
 ** used by the current version of SQLite.  Future versions of SQLite
 ** may add additional static mutexes.  Static mutexes are for internal
 ** use by SQLite only.  Applications that use SQLite mutexes should
@@ -15784,31 +18309,26 @@ static sqlite3_mutex *winMutexAlloc(int iType){
     case SQLITE_MUTEX_FAST:
     case SQLITE_MUTEX_RECURSIVE: {
       p = sqlite3MallocZero( sizeof(*p) );
-      if( p ){
+      if( p ){  
+#ifdef SQLITE_DEBUG
         p->id = iType;
+#endif
+#if SQLITE_OS_WINRT
+        InitializeCriticalSectionEx(&p->mutex, 0, 0);
+#else
         InitializeCriticalSection(&p->mutex);
+#endif
       }
       break;
     }
     default: {
-      static sqlite3_mutex staticMutexes[6];
-      static int isInit = 0;
-      while( !isInit ){
-        static long lock = 0;
-        if( InterlockedIncrement(&lock)==1 ){
-          int i;
-          for(i=0; i<sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++){
-            InitializeCriticalSection(&staticMutexes[i].mutex);
-          }
-          isInit = 1;
-        }else{
-          Sleep(1);
-        }
-      }
+      assert( winMutex_isInit==1 );
       assert( iType-2 >= 0 );
-      assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) );
-      p = &staticMutexes[iType-2];
+      assert( iType-2 < ArraySize(winMutex_staticMutexes) );
+      p = &winMutex_staticMutexes[iType-2];
+#ifdef SQLITE_DEBUG
       p->id = iType;
+#endif
       break;
     }
   }
@@ -15823,7 +18343,7 @@ static sqlite3_mutex *winMutexAlloc(int iType){
 */
 static void winMutexFree(sqlite3_mutex *p){
   assert( p );
-  assert( p->nRef==0 );
+  assert( p->nRef==0 && p->owner==0 );
   assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
   DeleteCriticalSection(&p->mutex);
   sqlite3_free(p);
@@ -15841,14 +18361,26 @@ static void winMutexFree(sqlite3_mutex *p){
 ** more than once, the behavior is undefined.
 */
 static void winMutexEnter(sqlite3_mutex *p){
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld(p) );
+#ifdef SQLITE_DEBUG
+  DWORD tid = GetCurrentThreadId(); 
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
+#endif
   EnterCriticalSection(&p->mutex);
-  p->owner = GetCurrentThreadId(); 
+#ifdef SQLITE_DEBUG
+  assert( p->nRef>0 || p->owner==0 );
+  p->owner = tid; 
   p->nRef++;
+  if( p->trace ){
+    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
 }
 static int winMutexTry(sqlite3_mutex *p){
+#ifndef NDEBUG
+  DWORD tid = GetCurrentThreadId(); 
+#endif
   int rc = SQLITE_BUSY;
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld(p) );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
   /*
   ** The sqlite3_mutex_try() routine is very rarely used, and when it
   ** is used it is merely an optimization.  So it is OK for it to always
@@ -15862,10 +18394,17 @@ static int winMutexTry(sqlite3_mutex *p){
   */
 #if 0
   if( mutexIsNT() && TryEnterCriticalSection(&p->mutex) ){
-    p->owner = GetCurrentThreadId();
+    p->owner = tid;
     p->nRef++;
     rc = SQLITE_OK;
   }
+#else
+  UNUSED_PARAMETER(p);
+#endif
+#ifdef SQLITE_DEBUG
+  if( rc==SQLITE_OK && p->trace ){
+    printf("try mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
 #endif
   return rc;
 }
@@ -15877,15 +18416,24 @@ static int winMutexTry(sqlite3_mutex *p){
 ** is not currently allocated.  SQLite will never do either.
 */
 static void winMutexLeave(sqlite3_mutex *p){
+#ifndef NDEBUG
+  DWORD tid = GetCurrentThreadId();
   assert( p->nRef>0 );
-  assert( p->owner==GetCurrentThreadId() );
+  assert( p->owner==tid );
   p->nRef--;
+  if( p->nRef==0 ) p->owner = 0;
   assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+#endif
   LeaveCriticalSection(&p->mutex);
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
 }
 
-SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
-  static sqlite3_mutex_methods sMutex = {
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
     winMutexInit,
     winMutexEnd,
     winMutexAlloc,
@@ -15921,9 +18469,68 @@ SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
 *************************************************************************
 **
 ** Memory allocation functions used throughout sqlite.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/* #include <stdarg.h> */
+
+/*
+** Attempt to release up to n bytes of non-essential memory currently
+** held by SQLite. An example of non-essential memory is memory used to
+** cache database pages that are not currently in use.
+*/
+SQLITE_API int sqlite3_release_memory(int n){
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  return sqlite3PcacheReleaseMemory(n);
+#else
+  /* IMPLEMENTATION-OF: R-34391-24921 The sqlite3_release_memory() routine
+  ** is a no-op returning zero if SQLite is not compiled with
+  ** SQLITE_ENABLE_MEMORY_MANAGEMENT. */
+  UNUSED_PARAMETER(n);
+  return 0;
+#endif
+}
+
+/*
+** An instance of the following object records the location of
+** each unused scratch buffer.
+*/
+typedef struct ScratchFreeslot {
+  struct ScratchFreeslot *pNext;   /* Next unused scratch buffer */
+} ScratchFreeslot;
+
+/*
+** State information local to the memory allocation subsystem.
+*/
+static SQLITE_WSD struct Mem0Global {
+  sqlite3_mutex *mutex;         /* Mutex to serialize access */
+
+  /*
+  ** The alarm callback and its arguments.  The mem0.mutex lock will
+  ** be held while the callback is running.  Recursive calls into
+  ** the memory subsystem are allowed, but no new callbacks will be
+  ** issued.
+  */
+  sqlite3_int64 alarmThreshold;
+  void (*alarmCallback)(void*, sqlite3_int64,int);
+  void *alarmArg;
+
+  /*
+  ** Pointers to the end of sqlite3GlobalConfig.pScratch memory
+  ** (so that a range test can be used to determine if an allocation
+  ** being freed came from pScratch) and a pointer to the list of
+  ** unused scratch allocations.
+  */
+  void *pScratchEnd;
+  ScratchFreeslot *pScratchFree;
+  u32 nScratchFree;
+
+  /*
+  ** True if heap is nearly "full" where "full" is defined by the
+  ** sqlite3_soft_heap_limit() setting.
+  */
+  int nearlyFull;
+} mem0 = { 0, 0, 0, 0, 0, 0, 0, 0 };
+
+#define mem0 GLOBAL(struct Mem0Global, mem0)
 
 /*
 ** This routine runs when the memory allocator sees that the
@@ -15939,82 +18546,68 @@ static void softHeapLimitEnforcer(
   sqlite3_release_memory(allocSize);
 }
 
+/*
+** Change the alarm callback
+*/
+static int sqlite3MemoryAlarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  int nUsed;
+  sqlite3_mutex_enter(mem0.mutex);
+  mem0.alarmCallback = xCallback;
+  mem0.alarmArg = pArg;
+  mem0.alarmThreshold = iThreshold;
+  nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+  mem0.nearlyFull = (iThreshold>0 && iThreshold<=nUsed);
+  sqlite3_mutex_leave(mem0.mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Deprecated external interface.  Internal/core SQLite code
+** should call sqlite3MemoryAlarm.
+*/
+SQLITE_API int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  return sqlite3MemoryAlarm(xCallback, pArg, iThreshold);
+}
+#endif
+
 /*
 ** Set the soft heap-size limit for the library. Passing a zero or 
 ** negative value indicates no limit.
 */
-SQLITE_API void sqlite3_soft_heap_limit(int n){
-  sqlite3_uint64 iLimit;
-  int overage;
-  if( n<0 ){
-    iLimit = 0;
-  }else{
-    iLimit = n;
-  }
-  sqlite3_initialize();
-  if( iLimit>0 ){
-    sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, iLimit);
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
+  sqlite3_int64 priorLimit;
+  sqlite3_int64 excess;
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return -1;
+#endif
+  sqlite3_mutex_enter(mem0.mutex);
+  priorLimit = mem0.alarmThreshold;
+  sqlite3_mutex_leave(mem0.mutex);
+  if( n<0 ) return priorLimit;
+  if( n>0 ){
+    sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, n);
   }else{
     sqlite3MemoryAlarm(0, 0, 0);
   }
-  overage = (int)(sqlite3_memory_used() - (i64)n);
-  if( overage>0 ){
-    sqlite3_release_memory(overage);
-  }
+  excess = sqlite3_memory_used() - n;
+  if( excess>0 ) sqlite3_release_memory((int)(excess & 0x7fffffff));
+  return priorLimit;
 }
-
-/*
-** Attempt to release up to n bytes of non-essential memory currently
-** held by SQLite. An example of non-essential memory is memory used to
-** cache database pages that are not currently in use.
-*/
-SQLITE_API int sqlite3_release_memory(int n){
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
-  int nRet = 0;
-#if 0
-  nRet += sqlite3VdbeReleaseMemory(n);
-#endif
-  nRet += sqlite3PcacheReleaseMemory(n-nRet);
-  return nRet;
-#else
-  UNUSED_PARAMETER(n);
-  return SQLITE_OK;
-#endif
+SQLITE_API void sqlite3_soft_heap_limit(int n){
+  if( n<0 ) n = 0;
+  sqlite3_soft_heap_limit64(n);
 }
 
-/*
-** State information local to the memory allocation subsystem.
-*/
-static SQLITE_WSD struct Mem0Global {
-  /* Number of free pages for scratch and page-cache memory */
-  u32 nScratchFree;
-  u32 nPageFree;
-
-  sqlite3_mutex *mutex;         /* Mutex to serialize access */
-
-  /*
-  ** The alarm callback and its arguments.  The mem0.mutex lock will
-  ** be held while the callback is running.  Recursive calls into
-  ** the memory subsystem are allowed, but no new callbacks will be
-  ** issued.  The alarmBusy variable is set to prevent recursive
-  ** callbacks.
-  */
-  sqlite3_int64 alarmThreshold;
-  void (*alarmCallback)(void*, sqlite3_int64,int);
-  void *alarmArg;
-  int alarmBusy;
-
-  /*
-  ** Pointers to the end of sqlite3GlobalConfig.pScratch and
-  ** sqlite3GlobalConfig.pPage to a block of memory that records
-  ** which pages are available.
-  */
-  u32 *aScratchFree;
-  u32 *aPageFree;
-} mem0 = { 62560955, 0, 0, 0, 0, 0, 0, 0, 0 };
-
-#define mem0 GLOBAL(struct Mem0Global, mem0)
-
 /*
 ** Initialize the memory allocation subsystem.
 */
@@ -16027,41 +18620,52 @@ SQLITE_PRIVATE int sqlite3MallocInit(void){
     mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
   }
   if( sqlite3GlobalConfig.pScratch && sqlite3GlobalConfig.szScratch>=100
-      && sqlite3GlobalConfig.nScratch>=0 ){
-    int i;
-    sqlite3GlobalConfig.szScratch = (sqlite3GlobalConfig.szScratch - 4) & ~7;
-    mem0.aScratchFree = (u32*)&((char*)sqlite3GlobalConfig.pScratch)
-                  [sqlite3GlobalConfig.szScratch*sqlite3GlobalConfig.nScratch];
-    for(i=0; i<sqlite3GlobalConfig.nScratch; i++){ mem0.aScratchFree[i] = i; }
-    mem0.nScratchFree = sqlite3GlobalConfig.nScratch;
+      && sqlite3GlobalConfig.nScratch>0 ){
+    int i, n, sz;
+    ScratchFreeslot *pSlot;
+    sz = ROUNDDOWN8(sqlite3GlobalConfig.szScratch);
+    sqlite3GlobalConfig.szScratch = sz;
+    pSlot = (ScratchFreeslot*)sqlite3GlobalConfig.pScratch;
+    n = sqlite3GlobalConfig.nScratch;
+    mem0.pScratchFree = pSlot;
+    mem0.nScratchFree = n;
+    for(i=0; i<n-1; i++){
+      pSlot->pNext = (ScratchFreeslot*)(sz+(char*)pSlot);
+      pSlot = pSlot->pNext;
+    }
+    pSlot->pNext = 0;
+    mem0.pScratchEnd = (void*)&pSlot[1];
   }else{
+    mem0.pScratchEnd = 0;
     sqlite3GlobalConfig.pScratch = 0;
     sqlite3GlobalConfig.szScratch = 0;
+    sqlite3GlobalConfig.nScratch = 0;
   }
-  if( sqlite3GlobalConfig.pPage && sqlite3GlobalConfig.szPage>=512
-      && sqlite3GlobalConfig.nPage>=1 ){
-    int i;
-    int overhead;
-    int sz = sqlite3GlobalConfig.szPage & ~7;
-    int n = sqlite3GlobalConfig.nPage;
-    overhead = (4*n + sz - 1)/sz;
-    sqlite3GlobalConfig.nPage -= overhead;
-    mem0.aPageFree = (u32*)&((char*)sqlite3GlobalConfig.pPage)
-                  [sqlite3GlobalConfig.szPage*sqlite3GlobalConfig.nPage];
-    for(i=0; i<sqlite3GlobalConfig.nPage; i++){ mem0.aPageFree[i] = i; }
-    mem0.nPageFree = sqlite3GlobalConfig.nPage;
-  }else{
+  if( sqlite3GlobalConfig.pPage==0 || sqlite3GlobalConfig.szPage<512
+      || sqlite3GlobalConfig.nPage<1 ){
     sqlite3GlobalConfig.pPage = 0;
     sqlite3GlobalConfig.szPage = 0;
+    sqlite3GlobalConfig.nPage = 0;
   }
   return sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);
 }
 
+/*
+** Return true if the heap is currently under memory pressure - in other
+** words if the amount of heap used is close to the limit set by
+** sqlite3_soft_heap_limit().
+*/
+SQLITE_PRIVATE int sqlite3HeapNearlyFull(void){
+  return mem0.nearlyFull;
+}
+
 /*
 ** Deinitialize the memory allocation subsystem.
 */
 SQLITE_PRIVATE void sqlite3MallocEnd(void){
-  sqlite3GlobalConfig.m.xShutdown(sqlite3GlobalConfig.m.pAppData);
+  if( sqlite3GlobalConfig.m.xShutdown ){
+    sqlite3GlobalConfig.m.xShutdown(sqlite3GlobalConfig.m.pAppData);
+  }
   memset(&mem0, 0, sizeof(mem0));
 }
 
@@ -16089,36 +18693,6 @@ SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
   return res;
 }
 
-/*
-** Change the alarm callback
-*/
-SQLITE_PRIVATE int sqlite3MemoryAlarm(
-  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
-  void *pArg,
-  sqlite3_int64 iThreshold
-){
-  sqlite3_mutex_enter(mem0.mutex);
-  mem0.alarmCallback = xCallback;
-  mem0.alarmArg = pArg;
-  mem0.alarmThreshold = iThreshold;
-  sqlite3_mutex_leave(mem0.mutex);
-  return SQLITE_OK;
-}
-
-#ifndef SQLITE_OMIT_DEPRECATED
-/*
-** Deprecated external interface.  Internal/core SQLite code
-** should call sqlite3MemoryAlarm.
-*/
-SQLITE_API int sqlite3_memory_alarm(
-  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
-  void *pArg,
-  sqlite3_int64 iThreshold
-){
-  return sqlite3MemoryAlarm(xCallback, pArg, iThreshold);
-}
-#endif
-
 /*
 ** Trigger the alarm 
 */
@@ -16126,15 +18700,16 @@ static void sqlite3MallocAlarm(int nByte){
   void (*xCallback)(void*,sqlite3_int64,int);
   sqlite3_int64 nowUsed;
   void *pArg;
-  if( mem0.alarmCallback==0 || mem0.alarmBusy  ) return;
-  mem0.alarmBusy = 1;
+  if( mem0.alarmCallback==0 ) return;
   xCallback = mem0.alarmCallback;
   nowUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
   pArg = mem0.alarmArg;
+  mem0.alarmCallback = 0;
   sqlite3_mutex_leave(mem0.mutex);
   xCallback(pArg, nowUsed, nByte);
   sqlite3_mutex_enter(mem0.mutex);
-  mem0.alarmBusy = 0;
+  mem0.alarmCallback = xCallback;
+  mem0.alarmArg = pArg;
 }
 
 /*
@@ -16149,18 +18724,24 @@ static int mallocWithAlarm(int n, void **pp){
   sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, n);
   if( mem0.alarmCallback!=0 ){
     int nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
-    if( nUsed+nFull >= mem0.alarmThreshold ){
+    if( nUsed >= mem0.alarmThreshold - nFull ){
+      mem0.nearlyFull = 1;
       sqlite3MallocAlarm(nFull);
+    }else{
+      mem0.nearlyFull = 0;
     }
   }
   p = sqlite3GlobalConfig.m.xMalloc(nFull);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
   if( p==0 && mem0.alarmCallback ){
     sqlite3MallocAlarm(nFull);
     p = sqlite3GlobalConfig.m.xMalloc(nFull);
   }
+#endif
   if( p ){
     nFull = sqlite3MallocSize(p);
     sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nFull);
+    sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, 1);
   }
   *pp = p;
   return nFull;
@@ -16172,7 +18753,14 @@ static int mallocWithAlarm(int n, void **pp){
 */
 SQLITE_PRIVATE void *sqlite3Malloc(int n){
   void *p;
-  if( n<=0 ){
+  if( n<=0               /* IMP: R-65312-04917 */ 
+   || n>=0x7fffff00
+  ){
+    /* A memory allocation of a number of bytes which is near the maximum
+    ** signed integer value might cause an integer overflow inside of the
+    ** xMalloc().  Hence we limit the maximum size to 0x7fffff00, giving
+    ** 255 bytes of overhead.  SQLite itself will never use anything near
+    ** this amount.  The only way to reach the limit is with sqlite3_malloc() */
     p = 0;
   }else if( sqlite3GlobalConfig.bMemstat ){
     sqlite3_mutex_enter(mem0.mutex);
@@ -16181,6 +18769,7 @@ SQLITE_PRIVATE void *sqlite3Malloc(int n){
   }else{
     p = sqlite3GlobalConfig.m.xMalloc(n);
   }
+  assert( EIGHT_BYTE_ALIGNMENT(p) );  /* IMP: R-04675-44850 */
   return p;
 }
 
@@ -16219,187 +18808,89 @@ SQLITE_PRIVATE void *sqlite3ScratchMalloc(int n){
   void *p;
   assert( n>0 );
 
+  sqlite3_mutex_enter(mem0.mutex);
+  if( mem0.nScratchFree && sqlite3GlobalConfig.szScratch>=n ){
+    p = mem0.pScratchFree;
+    mem0.pScratchFree = mem0.pScratchFree->pNext;
+    mem0.nScratchFree--;
+    sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, 1);
+    sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    if( sqlite3GlobalConfig.bMemstat ){
+      sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);
+      n = mallocWithAlarm(n, &p);
+      if( p ) sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, n);
+      sqlite3_mutex_leave(mem0.mutex);
+    }else{
+      sqlite3_mutex_leave(mem0.mutex);
+      p = sqlite3GlobalConfig.m.xMalloc(n);
+    }
+    sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);
+  }
+  assert( sqlite3_mutex_notheld(mem0.mutex) );
+
+
 #if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
-  /* Verify that no more than one scratch allocation per thread
-  ** is outstanding at one time.  (This is only checked in the
+  /* Verify that no more than two scratch allocations per thread
+  ** are outstanding at one time.  (This is only checked in the
   ** single-threaded case since checking in the multi-threaded case
   ** would be much more complicated.) */
-  assert( scratchAllocOut==0 );
-#endif
-
-  if( sqlite3GlobalConfig.szScratch<n ){
-    goto scratch_overflow;
-  }else{  
-    sqlite3_mutex_enter(mem0.mutex);
-    if( mem0.nScratchFree==0 ){
-      sqlite3_mutex_leave(mem0.mutex);
-      goto scratch_overflow;
-    }else{
-      int i;
-      i = mem0.aScratchFree[--mem0.nScratchFree];
-      i *= sqlite3GlobalConfig.szScratch;
-      sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, 1);
-      sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);
-      sqlite3_mutex_leave(mem0.mutex);
-      p = (void*)&((char*)sqlite3GlobalConfig.pScratch)[i];
-      assert(  (((u8*)p - (u8*)0) & 7)==0 );
-    }
-  }
-#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
-  scratchAllocOut = p!=0;
+  assert( scratchAllocOut<=1 );
+  if( p ) scratchAllocOut++;
 #endif
 
   return p;
-
-scratch_overflow:
-  if( sqlite3GlobalConfig.bMemstat ){
-    sqlite3_mutex_enter(mem0.mutex);
-    sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);
-    n = mallocWithAlarm(n, &p);
-    if( p ) sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, n);
-    sqlite3_mutex_leave(mem0.mutex);
-  }else{
-    p = sqlite3GlobalConfig.m.xMalloc(n);
-  }
-#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
-  scratchAllocOut = p!=0;
-#endif
-  return p;    
 }
 SQLITE_PRIVATE void sqlite3ScratchFree(void *p){
   if( p ){
 
 #if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
-    /* Verify that no more than one scratch allocation per thread
+    /* Verify that no more than two scratch allocation per thread
     ** is outstanding at one time.  (This is only checked in the
     ** single-threaded case since checking in the multi-threaded case
     ** would be much more complicated.) */
-    assert( scratchAllocOut==1 );
-    scratchAllocOut = 0;
+    assert( scratchAllocOut>=1 && scratchAllocOut<=2 );
+    scratchAllocOut--;
 #endif
 
-    if( sqlite3GlobalConfig.pScratch==0
-           || p<sqlite3GlobalConfig.pScratch
-           || p>=(void*)mem0.aScratchFree ){
+    if( p>=sqlite3GlobalConfig.pScratch && p<mem0.pScratchEnd ){
+      /* Release memory from the SQLITE_CONFIG_SCRATCH allocation */
+      ScratchFreeslot *pSlot;
+      pSlot = (ScratchFreeslot*)p;
+      sqlite3_mutex_enter(mem0.mutex);
+      pSlot->pNext = mem0.pScratchFree;
+      mem0.pScratchFree = pSlot;
+      mem0.nScratchFree++;
+      assert( mem0.nScratchFree <= (u32)sqlite3GlobalConfig.nScratch );
+      sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, -1);
+      sqlite3_mutex_leave(mem0.mutex);
+    }else{
+      /* Release memory back to the heap */
+      assert( sqlite3MemdebugHasType(p, MEMTYPE_SCRATCH) );
+      assert( sqlite3MemdebugNoType(p, ~MEMTYPE_SCRATCH) );
+      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
       if( sqlite3GlobalConfig.bMemstat ){
         int iSize = sqlite3MallocSize(p);
         sqlite3_mutex_enter(mem0.mutex);
         sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, -iSize);
         sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -iSize);
+        sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);
         sqlite3GlobalConfig.m.xFree(p);
         sqlite3_mutex_leave(mem0.mutex);
       }else{
         sqlite3GlobalConfig.m.xFree(p);
       }
-    }else{
-      int i;
-      i = (int)((u8*)p - (u8*)sqlite3GlobalConfig.pScratch);
-      i /= sqlite3GlobalConfig.szScratch;
-      assert( i>=0 && i<sqlite3GlobalConfig.nScratch );
-      sqlite3_mutex_enter(mem0.mutex);
-      assert( mem0.nScratchFree<(u32)sqlite3GlobalConfig.nScratch );
-      mem0.aScratchFree[mem0.nScratchFree++] = i;
-      sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, -1);
-      sqlite3_mutex_leave(mem0.mutex);
     }
   }
 }
 
-/*
-** Allocate memory to be used by the page cache.  Make use of the
-** memory buffer provided by SQLITE_CONFIG_PAGECACHE if there is one
-** and that memory is of the right size and is not completely
-** consumed.  Otherwise, failover to sqlite3Malloc().
-*/
-#if 0
-SQLITE_PRIVATE void *sqlite3PageMalloc(int n){
-  void *p;
-  assert( n>0 );
-  assert( (n & (n-1))==0 );
-  assert( n>=512 && n<=32768 );
-
-  if( sqlite3GlobalConfig.szPage<n ){
-    goto page_overflow;
-  }else{  
-    sqlite3_mutex_enter(mem0.mutex);
-    if( mem0.nPageFree==0 ){
-      sqlite3_mutex_leave(mem0.mutex);
-      goto page_overflow;
-    }else{
-      int i;
-      i = mem0.aPageFree[--mem0.nPageFree];
-      sqlite3_mutex_leave(mem0.mutex);
-      i *= sqlite3GlobalConfig.szPage;
-      sqlite3StatusSet(SQLITE_STATUS_PAGECACHE_SIZE, n);
-      sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, 1);
-      p = (void*)&((char*)sqlite3GlobalConfig.pPage)[i];
-    }
-  }
-  return p;
-
-page_overflow:
-  if( sqlite3GlobalConfig.bMemstat ){
-    sqlite3_mutex_enter(mem0.mutex);
-    sqlite3StatusSet(SQLITE_STATUS_PAGECACHE_SIZE, n);
-    n = mallocWithAlarm(n, &p);
-    if( p ) sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, n);
-    sqlite3_mutex_leave(mem0.mutex);
-  }else{
-    p = sqlite3GlobalConfig.m.xMalloc(n);
-  }
-  return p;    
-}
-SQLITE_PRIVATE void sqlite3PageFree(void *p){
-  if( p ){
-    if( sqlite3GlobalConfig.pPage==0
-           || p<sqlite3GlobalConfig.pPage
-           || p>=(void*)mem0.aPageFree ){
-      /* In this case, the page allocation was obtained from a regular 
-      ** call to sqlite3_mem_methods.xMalloc() (a page-cache-memory 
-      ** "overflow"). Free the block with sqlite3_mem_methods.xFree().
-      */
-      if( sqlite3GlobalConfig.bMemstat ){
-        int iSize = sqlite3MallocSize(p);
-        sqlite3_mutex_enter(mem0.mutex);
-        sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, -iSize);
-        sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -iSize);
-        sqlite3GlobalConfig.m.xFree(p);
-        sqlite3_mutex_leave(mem0.mutex);
-      }else{
-        sqlite3GlobalConfig.m.xFree(p);
-      }
-    }else{
-      /* The page allocation was allocated from the sqlite3GlobalConfig.pPage
-      ** buffer. In this case all that is add the index of the page in
-      ** the sqlite3GlobalConfig.pPage array to the set of free indexes stored
-      ** in the mem0.aPageFree[] array.
-      */
-      int i;
-      i = (u8 *)p - (u8 *)sqlite3GlobalConfig.pPage;
-      i /= sqlite3GlobalConfig.szPage;
-      assert( i>=0 && i<sqlite3GlobalConfig.nPage );
-      sqlite3_mutex_enter(mem0.mutex);
-      assert( mem0.nPageFree<sqlite3GlobalConfig.nPage );
-      mem0.aPageFree[mem0.nPageFree++] = i;
-      sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, -1);
-      sqlite3_mutex_leave(mem0.mutex);
-#if !defined(NDEBUG) && 0
-      /* Assert that a duplicate was not just inserted into aPageFree[]. */
-      for(i=0; i<mem0.nPageFree-1; i++){
-        assert( mem0.aPageFree[i]!=mem0.aPageFree[mem0.nPageFree-1] );
-      }
-#endif
-    }
-  }
-}
-#endif
-
 /*
 ** TRUE if p is a lookaside memory allocation from db
 */
 #ifndef SQLITE_OMIT_LOOKASIDE
 static int isLookaside(sqlite3 *db, void *p){
-  return db && p && p>=db->lookaside.pStart && p<db->lookaside.pEnd;
+  return p && p>=db->lookaside.pStart && p<db->lookaside.pEnd;
 }
 #else
 #define isLookaside(A,B) 0
@@ -16410,14 +18901,18 @@ static int isLookaside(sqlite3 *db, void *p){
 ** sqlite3Malloc() or sqlite3_malloc().
 */
 SQLITE_PRIVATE int sqlite3MallocSize(void *p){
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
   return sqlite3GlobalConfig.m.xSize(p);
 }
 SQLITE_PRIVATE int sqlite3DbMallocSize(sqlite3 *db, void *p){
-  if( p==0 ){
-    return 0;
-  }else if( isLookaside(db, p) ){
+  assert( db==0 || sqlite3_mutex_held(db->mutex) );
+  if( db && isLookaside(db, p) ){
     return db->lookaside.sz;
   }else{
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );
+    assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
     return sqlite3GlobalConfig.m.xSize(p);
   }
 }
@@ -16426,10 +18921,13 @@ SQLITE_PRIVATE int sqlite3DbMallocSize(sqlite3 *db, void *p){
 ** Free memory previously obtained from sqlite3Malloc().
 */
 SQLITE_API void sqlite3_free(void *p){
-  if( p==0 ) return;
+  if( p==0 ) return;  /* IMP: R-49053-54554 */
+  assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
   if( sqlite3GlobalConfig.bMemstat ){
     sqlite3_mutex_enter(mem0.mutex);
     sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -sqlite3MallocSize(p));
+    sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);
     sqlite3GlobalConfig.m.xFree(p);
     sqlite3_mutex_leave(mem0.mutex);
   }else{
@@ -16442,55 +18940,79 @@ SQLITE_API void sqlite3_free(void *p){
 ** connection.
 */
 SQLITE_PRIVATE void sqlite3DbFree(sqlite3 *db, void *p){
-  if( isLookaside(db, p) ){
-    LookasideSlot *pBuf = (LookasideSlot*)p;
-    pBuf->pNext = db->lookaside.pFree;
-    db->lookaside.pFree = pBuf;
-    db->lookaside.nOut--;
-  }else{
-    sqlite3_free(p);
+  assert( db==0 || sqlite3_mutex_held(db->mutex) );
+  if( db ){
+    if( db->pnBytesFreed ){
+      *db->pnBytesFreed += sqlite3DbMallocSize(db, p);
+      return;
+    }
+    if( isLookaside(db, p) ){
+      LookasideSlot *pBuf = (LookasideSlot*)p;
+#if SQLITE_DEBUG
+      /* Trash all content in the buffer being freed */
+      memset(p, 0xaa, db->lookaside.sz);
+#endif
+      pBuf->pNext = db->lookaside.pFree;
+      db->lookaside.pFree = pBuf;
+      db->lookaside.nOut--;
+      return;
+    }
   }
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );
+  assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  sqlite3_free(p);
 }
 
 /*
 ** Change the size of an existing memory allocation
 */
 SQLITE_PRIVATE void *sqlite3Realloc(void *pOld, int nBytes){
-  int nOld, nNew;
+  int nOld, nNew, nDiff;
   void *pNew;
   if( pOld==0 ){
-    return sqlite3Malloc(nBytes);
+    return sqlite3Malloc(nBytes); /* IMP: R-28354-25769 */
   }
   if( nBytes<=0 ){
-    sqlite3_free(pOld);
+    sqlite3_free(pOld); /* IMP: R-31593-10574 */
+    return 0;
+  }
+  if( nBytes>=0x7fffff00 ){
+    /* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */
     return 0;
   }
   nOld = sqlite3MallocSize(pOld);
-  if( sqlite3GlobalConfig.bMemstat ){
+  /* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second
+  ** argument to xRealloc is always a value returned by a prior call to
+  ** xRoundup. */
+  nNew = sqlite3GlobalConfig.m.xRoundup(nBytes);
+  if( nOld==nNew ){
+    pNew = pOld;
+  }else if( sqlite3GlobalConfig.bMemstat ){
     sqlite3_mutex_enter(mem0.mutex);
     sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, nBytes);
-    nNew = sqlite3GlobalConfig.m.xRoundup(nBytes);
-    if( nOld==nNew ){
-      pNew = pOld;
-    }else{
-      if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED)+nNew-nOld >= 
-            mem0.alarmThreshold ){
-        sqlite3MallocAlarm(nNew-nOld);
-      }
+    nDiff = nNew - nOld;
+    if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED) >= 
+          mem0.alarmThreshold-nDiff ){
+      sqlite3MallocAlarm(nDiff);
+    }
+    assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
+    assert( sqlite3MemdebugNoType(pOld, ~MEMTYPE_HEAP) );
+    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+    if( pNew==0 && mem0.alarmCallback ){
+      sqlite3MallocAlarm(nBytes);
       pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
-      if( pNew==0 && mem0.alarmCallback ){
-        sqlite3MallocAlarm(nBytes);
-        pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
-      }
-      if( pNew ){
-        nNew = sqlite3MallocSize(pNew);
-        sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
-      }
+    }
+    if( pNew ){
+      nNew = sqlite3MallocSize(pNew);
+      sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
     }
     sqlite3_mutex_leave(mem0.mutex);
   }else{
-    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nBytes);
+    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
   }
+  assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-04675-44850 */
   return pNew;
 }
 
@@ -16549,20 +19071,28 @@ SQLITE_PRIVATE void *sqlite3DbMallocZero(sqlite3 *db, int n){
 */
 SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3 *db, int n){
   void *p;
+  assert( db==0 || sqlite3_mutex_held(db->mutex) );
+  assert( db==0 || db->pnBytesFreed==0 );
 #ifndef SQLITE_OMIT_LOOKASIDE
   if( db ){
     LookasideSlot *pBuf;
     if( db->mallocFailed ){
       return 0;
     }
-    if( db->lookaside.bEnabled && n<=db->lookaside.sz
-         && (pBuf = db->lookaside.pFree)!=0 ){
-      db->lookaside.pFree = pBuf->pNext;
-      db->lookaside.nOut++;
-      if( db->lookaside.nOut>db->lookaside.mxOut ){
-        db->lookaside.mxOut = db->lookaside.nOut;
+    if( db->lookaside.bEnabled ){
+      if( n>db->lookaside.sz ){
+        db->lookaside.anStat[1]++;
+      }else if( (pBuf = db->lookaside.pFree)==0 ){
+        db->lookaside.anStat[2]++;
+      }else{
+        db->lookaside.pFree = pBuf->pNext;
+        db->lookaside.nOut++;
+        db->lookaside.anStat[0]++;
+        if( db->lookaside.nOut>db->lookaside.mxOut ){
+          db->lookaside.mxOut = db->lookaside.nOut;
+        }
+        return (void*)pBuf;
       }
-      return (void*)pBuf;
     }
   }
 #else
@@ -16574,6 +19104,8 @@ SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3 *db, int n){
   if( !p && db ){
     db->mallocFailed = 1;
   }
+  sqlite3MemdebugSetType(p, MEMTYPE_DB |
+         ((db && db->lookaside.bEnabled) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
   return p;
 }
 
@@ -16583,6 +19115,8 @@ SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3 *db, int n){
 */
 SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
   void *pNew = 0;
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
   if( db->mallocFailed==0 ){
     if( p==0 ){
       return sqlite3DbMallocRaw(db, n);
@@ -16597,10 +19131,16 @@ SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
         sqlite3DbFree(db, p);
       }
     }else{
+      assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
+      assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );
+      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
       pNew = sqlite3_realloc(p, n);
       if( !pNew ){
+        sqlite3MemdebugSetType(p, MEMTYPE_DB|MEMTYPE_HEAP);
         db->mallocFailed = 1;
       }
+      sqlite3MemdebugSetType(pNew, MEMTYPE_DB | 
+            (db->lookaside.bEnabled ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
     }
   }
   return pNew;
@@ -16632,7 +19172,7 @@ SQLITE_PRIVATE char *sqlite3DbStrDup(sqlite3 *db, const char *z){
   if( z==0 ){
     return 0;
   }
-  n = (db ? sqlite3Strlen(db, z) : sqlite3Strlen30(z))+1;
+  n = sqlite3Strlen30(z) + 1;
   assert( (n&0x7fffffff)==n );
   zNew = sqlite3DbMallocRaw(db, (int)n);
   if( zNew ){
@@ -16677,10 +19217,10 @@ SQLITE_PRIVATE void sqlite3SetString(char **pz, sqlite3 *db, const char *zFormat
 ** sqlite3_realloc.
 **
 ** The returned value is normally a copy of the second argument to this
-** function. However, if a malloc() failure has occured since the previous
+** function. However, if a malloc() failure has occurred since the previous
 ** invocation SQLITE_NOMEM is returned instead. 
 **
-** If the first argument, db, is not NULL and a malloc() error has occured,
+** If the first argument, db, is not NULL and a malloc() error has occurred,
 ** then the connection error-code (the value returned by sqlite3_errcode())
 ** is set to SQLITE_NOMEM.
 */
@@ -16707,52 +19247,12 @@ SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
 ** an historical reference.  Most of the "enhancements" have been backed
 ** out so that the functionality is now the same as standard printf().
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-**
 **************************************************************************
 **
-** The following modules is an enhanced replacement for the "printf" subroutines
-** found in the standard C library.  The following enhancements are
-** supported:
-**
-**      +  Additional functions.  The standard set of "printf" functions
-**         includes printf, fprintf, sprintf, vprintf, vfprintf, and
-**         vsprintf.  This module adds the following:
-**
-**           *  snprintf -- Works like sprintf, but has an extra argument
-**                          which is the size of the buffer written to.
-**
-**           *  mprintf --  Similar to sprintf.  Writes output to memory
-**                          obtained from malloc.
-**
-**           *  xprintf --  Calls a function to dispose of output.
-**
-**           *  nprintf --  No output, but returns the number of characters
-**                          that would have been output by printf.
-**
-**           *  A v- version (ex: vsnprintf) of every function is also
-**              supplied.
-**
-**      +  A few extensions to the formatting notation are supported:
-**
-**           *  The "=" flag (similar to "-") causes the output to be
-**              be centered in the appropriately sized field.
-**
-**           *  The %b field outputs an integer in binary notation.
-**
-**           *  The %c field now accepts a precision.  The character output
-**              is repeated by the number of times the precision specifies.
-**
-**           *  The %' field works like %c, but takes as its character the
-**              next character of the format string, instead of the next
-**              argument.  For example,  printf("%.78'-")  prints 78 minus
-**              signs, the same as  printf("%.78c",'-').
-**
-**      +  When compiled using GCC on a SPARC, this version of printf is
-**         faster than the library printf for SUN OS 4.1.
-**
-**      +  All functions are fully reentrant.
-**
+** This file contains code for a set of "printf"-like routines.  These
+** routines format strings much like the printf() from the standard C
+** library, though the implementation here has enhancements to support
+** SQLlite.
 */
 
 /*
@@ -16778,6 +19278,8 @@ SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
 #define etSQLESCAPE3 15 /* %w -> Strings with '\"' doubled */
 #define etORDINAL    16 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
 
+#define etINVALID     0 /* Any unrecognized conversion type */
+
 
 /*
 ** An "etByte" is an 8-bit unsigned value.
@@ -16834,6 +19336,9 @@ static const et_info fmtinfo[] = {
   {  'n',  0, 0, etSIZE,       0,  0 },
   {  '%',  0, 0, etPERCENT,    0,  0 },
   {  'p', 16, 0, etPOINTER,    0,  1 },
+
+/* All the rest have the FLAG_INTERN bit set and are thus for internal
+** use only */
   {  'T',  0, 2, etTOKEN,      0,  0 },
   {  'S',  0, 2, etSRCLIST,    0,  0 },
   {  'r', 10, 3, etORDINAL,    0,  0 },
@@ -16860,7 +19365,8 @@ static const et_info fmtinfo[] = {
 static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
   int digit;
   LONGDOUBLE_TYPE d;
-  if( (*cnt)++ >= 16 ) return '0';
+  if( (*cnt)<=0 ) return '0';
+  (*cnt)--;
   digit = (int)*val;
   d = digit;
   digit += '0';
@@ -16872,7 +19378,7 @@ static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
 /*
 ** Append N space characters to the given string buffer.
 */
-static void appendSpace(StrAccum *pAccum, int N){
+SQLITE_PRIVATE void sqlite3AppendSpace(StrAccum *pAccum, int N){
   static const char zSpaces[] = "                             ";
   while( N>=(int)sizeof(zSpaces)-1 ){
     sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
@@ -16885,40 +19391,15 @@ static void appendSpace(StrAccum *pAccum, int N){
 
 /*
 ** On machines with a small stack size, you can redefine the
-** SQLITE_PRINT_BUF_SIZE to be less than 350.  But beware - for
-** smaller values some %f conversions may go into an infinite loop.
+** SQLITE_PRINT_BUF_SIZE to be something smaller, if desired.
 */
 #ifndef SQLITE_PRINT_BUF_SIZE
-# define SQLITE_PRINT_BUF_SIZE 350
+# define SQLITE_PRINT_BUF_SIZE 70
 #endif
 #define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
 
 /*
-** The root program.  All variations call this core.
-**
-** INPUTS:
-**   func   This is a pointer to a function taking three arguments
-**            1. A pointer to anything.  Same as the "arg" parameter.
-**            2. A pointer to the list of characters to be output
-**               (Note, this list is NOT null terminated.)
-**            3. An integer number of characters to be output.
-**               (Note: This number might be zero.)
-**
-**   arg    This is the pointer to anything which will be passed as the
-**          first argument to "func".  Use it for whatever you like.
-**
-**   fmt    This is the format string, as in the usual print.
-**
-**   ap     This is a pointer to a list of arguments.  Same as in
-**          vfprint.
-**
-** OUTPUTS:
-**          The return value is the total number of characters sent to
-**          the function "func".  Returns -1 on a error.
-**
-** Note that the order in which automatic variables are declared below
-** seems to make a big difference in determining how fast this beast
-** will run.
+** Render a string given by "fmt" into the StrAccum object.
 */
 SQLITE_PRIVATE void sqlite3VXPrintf(
   StrAccum *pAccum,                  /* Accumulate results here */
@@ -16941,23 +19422,23 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
   etByte flag_long;          /* True if "l" flag is present */
   etByte flag_longlong;      /* True if the "ll" flag is present */
   etByte done;               /* Loop termination flag */
+  etByte xtype = 0;          /* Conversion paradigm */
+  char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
   sqlite_uint64 longvalue;   /* Value for integer types */
   LONGDOUBLE_TYPE realvalue; /* Value for real types */
   const et_info *infop;      /* Pointer to the appropriate info structure */
-  char buf[etBUFSIZE];       /* Conversion buffer */
-  char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
-  etByte xtype = 0;          /* Conversion paradigm */
-  char *zExtra;              /* Extra memory used for etTCLESCAPE conversions */
+  char *zOut;                /* Rendering buffer */
+  int nOut;                  /* Size of the rendering buffer */
+  char *zExtra;              /* Malloced memory used by some conversion */
 #ifndef SQLITE_OMIT_FLOATING_POINT
   int  exp, e2;              /* exponent of real numbers */
+  int nsd;                   /* Number of significant digits returned */
   double rounder;            /* Used for rounding floating point values */
   etByte flag_dp;            /* True if decimal point should be shown */
   etByte flag_rtz;           /* True if trailing zeros should be removed */
-  etByte flag_exp;           /* True to force display of the exponent */
-  int nsd;                   /* Number of significant digits returned */
 #endif
+  char buf[etBUFSIZE];       /* Conversion buffer */
 
-  length = 0;
   bufpt = 0;
   for(; (c=(*fmt))!=0; ++fmt){
     if( c!='%' ){
@@ -17002,9 +19483,6 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
         c = *++fmt;
       }
     }
-    if( width > etBUFSIZE-10 ){
-      width = etBUFSIZE-10;
-    }
     /* Get the precision */
     if( c=='.' ){
       precision = 0;
@@ -17036,7 +19514,8 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
       flag_long = flag_longlong = 0;
     }
     /* Fetch the info entry for the field */
-    infop = 0;
+    infop = &fmtinfo[0];
+    xtype = etINVALID;
     for(idx=0; idx<ArraySize(fmtinfo); idx++){
       if( c==fmtinfo[idx].fmttype ){
         infop = &fmtinfo[idx];
@@ -17049,15 +19528,6 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
       }
     }
     zExtra = 0;
-    if( infop==0 ){
-      return;
-    }
-
-
-    /* Limit the precision to prevent overflowing buf[] during conversion */
-    if( precision>etBUFSIZE-40 && (infop->flags & FLAG_STRING)==0 ){
-      precision = etBUFSIZE-40;
-    }
 
     /*
     ** At this point, variables are initialized as follows:
@@ -17089,11 +19559,19 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
       case etRADIX:
         if( infop->flags & FLAG_SIGNED ){
           i64 v;
-          if( flag_longlong )   v = va_arg(ap,i64);
-          else if( flag_long )  v = va_arg(ap,long int);
-          else                  v = va_arg(ap,int);
+          if( flag_longlong ){
+            v = va_arg(ap,i64);
+          }else if( flag_long ){
+            v = va_arg(ap,long int);
+          }else{
+            v = va_arg(ap,int);
+          }
           if( v<0 ){
-            longvalue = -v;
+            if( v==SMALLEST_INT64 ){
+              longvalue = ((u64)1)<<63;
+            }else{
+              longvalue = -v;
+            }
             prefix = '-';
           }else{
             longvalue = v;
@@ -17102,25 +19580,39 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
             else                       prefix = 0;
           }
         }else{
-          if( flag_longlong )   longvalue = va_arg(ap,u64);
-          else if( flag_long )  longvalue = va_arg(ap,unsigned long int);
-          else                  longvalue = va_arg(ap,unsigned int);
+          if( flag_longlong ){
+            longvalue = va_arg(ap,u64);
+          }else if( flag_long ){
+            longvalue = va_arg(ap,unsigned long int);
+          }else{
+            longvalue = va_arg(ap,unsigned int);
+          }
           prefix = 0;
         }
         if( longvalue==0 ) flag_alternateform = 0;
         if( flag_zeropad && precision<width-(prefix!=0) ){
           precision = width-(prefix!=0);
         }
-        bufpt = &buf[etBUFSIZE-1];
+        if( precision<etBUFSIZE-10 ){
+          nOut = etBUFSIZE;
+          zOut = buf;
+        }else{
+          nOut = precision + 10;
+          zOut = zExtra = sqlite3Malloc( nOut );
+          if( zOut==0 ){
+            pAccum->mallocFailed = 1;
+            return;
+          }
+        }
+        bufpt = &zOut[nOut-1];
         if( xtype==etORDINAL ){
           static const char zOrd[] = "thstndrd";
           int x = (int)(longvalue % 10);
           if( x>=4 || (longvalue/10)%10==1 ){
             x = 0;
           }
-          buf[etBUFSIZE-3] = zOrd[x*2];
-          buf[etBUFSIZE-2] = zOrd[x*2+1];
-          bufpt -= 2;
+          *(--bufpt) = zOrd[x*2+1];
+          *(--bufpt) = zOrd[x*2];
         }
         {
           register const char *cset;      /* Use registers for speed */
@@ -17132,7 +19624,7 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
             longvalue = longvalue/base;
           }while( longvalue>0 );
         }
-        length = (int)(&buf[etBUFSIZE-1]-bufpt);
+        length = (int)(&zOut[nOut-1]-bufpt);
         for(idx=precision-length; idx>0; idx--){
           *(--bufpt) = '0';                             /* Zero pad */
         }
@@ -17143,15 +19635,16 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
           pre = &aPrefix[infop->prefix];
           for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
         }
-        length = (int)(&buf[etBUFSIZE-1]-bufpt);
+        length = (int)(&zOut[nOut-1]-bufpt);
         break;
       case etFLOAT:
       case etEXP:
       case etGENERIC:
         realvalue = va_arg(ap,double);
-#ifndef SQLITE_OMIT_FLOATING_POINT
+#ifdef SQLITE_OMIT_FLOATING_POINT
+        length = 0;
+#else
         if( precision<0 ) precision = 6;         /* Set default precision */
-        if( precision>etBUFSIZE/2-10 ) precision = etBUFSIZE/2-10;
         if( realvalue<0.0 ){
           realvalue = -realvalue;
           prefix = '-';
@@ -17177,9 +19670,12 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
           break;
         }
         if( realvalue>0.0 ){
-          while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }
-          while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
-          while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
+          LONGDOUBLE_TYPE scale = 1.0;
+          while( realvalue>=1e100*scale && exp<=350 ){ scale *= 1e100;exp+=100;}
+          while( realvalue>=1e64*scale && exp<=350 ){ scale *= 1e64; exp+=64; }
+          while( realvalue>=1e8*scale && exp<=350 ){ scale *= 1e8; exp+=8; }
+          while( realvalue>=10.0*scale && exp<=350 ){ scale *= 10.0; exp++; }
+          realvalue /= scale;
           while( realvalue<1e-8 ){ realvalue *= 1e8; exp-=8; }
           while( realvalue<1.0 ){ realvalue *= 10.0; exp--; }
           if( exp>350 ){
@@ -17199,7 +19695,6 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
         ** If the field type is etGENERIC, then convert to either etEXP
         ** or etFLOAT, as appropriate.
         */
-        flag_exp = xtype==etEXP;
         if( xtype!=etFLOAT ){
           realvalue += rounder;
           if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
@@ -17213,14 +19708,22 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
             xtype = etFLOAT;
           }
         }else{
-          flag_rtz = 0;
+          flag_rtz = flag_altform2;
         }
         if( xtype==etEXP ){
           e2 = 0;
         }else{
           e2 = exp;
         }
-        nsd = 0;
+        if( e2+precision+width > etBUFSIZE - 15 ){
+          bufpt = zExtra = sqlite3Malloc( e2+precision+width+15 );
+          if( bufpt==0 ){
+            pAccum->mallocFailed = 1;
+            return;
+          }
+        }
+        zOut = bufpt;
+        nsd = 16 + flag_altform2*10;
         flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
         /* The sign in front of the number */
         if( prefix ){
@@ -17251,7 +19754,7 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
         /* Remove trailing zeros and the "." if no digits follow the "." */
         if( flag_rtz && flag_dp ){
           while( bufpt[-1]=='0' ) *(--bufpt) = 0;
-          assert( bufpt>buf );
+          assert( bufpt>zOut );
           if( bufpt[-1]=='.' ){
             if( flag_altform2 ){
               *(bufpt++) = '0';
@@ -17261,7 +19764,7 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
           }
         }
         /* Add the "eNNN" suffix */
-        if( flag_exp || xtype==etEXP ){
+        if( xtype==etEXP ){
           *(bufpt++) = aDigits[infop->charset];
           if( exp<0 ){
             *(bufpt++) = '-'; exp = -exp;
@@ -17280,8 +19783,8 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
         /* The converted number is in buf[] and zero terminated. Output it.
         ** Note that the number is in the usual order, not reversed as with
         ** integer conversions. */
-        length = (int)(bufpt-buf);
-        bufpt = buf;
+        length = (int)(bufpt-zOut);
+        bufpt = zOut;
 
         /* Special case:  Add leading zeros if the flag_zeropad flag is
         ** set and we are not left justified */
@@ -17295,7 +19798,7 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
           while( nPad-- ) bufpt[i++] = '0';
           length = width;
         }
-#endif
+#endif /* !defined(SQLITE_OMIT_FLOATING_POINT) */
         break;
       case etSIZE:
         *(va_arg(ap,int*)) = pAccum->nChar;
@@ -17334,14 +19837,15 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
       case etSQLESCAPE:
       case etSQLESCAPE2:
       case etSQLESCAPE3: {
-        int i, j, n, isnull;
+        int i, j, k, n, isnull;
         int needQuote;
         char ch;
         char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
         char *escarg = va_arg(ap,char*);
         isnull = escarg==0;
         if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
-        for(i=n=0; (ch=escarg[i])!=0; i++){
+        k = precision;
+        for(i=n=0; k!=0 && (ch=escarg[i])!=0; i++, k--){
           if( ch==q )  n++;
         }
         needQuote = !isnull && xtype==etSQLESCAPE2;
@@ -17357,15 +19861,17 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
         }
         j = 0;
         if( needQuote ) bufpt[j++] = q;
-        for(i=0; (ch=escarg[i])!=0; i++){
-          bufpt[j++] = ch;
+        k = i;
+        for(i=0; i<k; i++){
+          bufpt[j++] = ch = escarg[i];
           if( ch==q ) bufpt[j++] = ch;
         }
         if( needQuote ) bufpt[j++] = q;
         bufpt[j] = 0;
         length = j;
-        /* The precision is ignored on %q and %Q */
-        /* if( precision>=0 && precision<length ) length = precision; */
+        /* The precision in %q and %Q means how many input characters to
+        ** consume, not the length of the output...
+        ** if( precision>=0 && precision<length ) length = precision; */
         break;
       }
       case etTOKEN: {
@@ -17389,6 +19895,10 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
         length = width = 0;
         break;
       }
+      default: {
+        assert( xtype==etINVALID );
+        return;
+      }
     }/* End switch over the format type */
     /*
     ** The text of the conversion is pointed to by "bufpt" and is
@@ -17399,7 +19909,7 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
       register int nspace;
       nspace = width-length;
       if( nspace>0 ){
-        appendSpace(pAccum, nspace);
+        sqlite3AppendSpace(pAccum, nspace);
       }
     }
     if( length>0 ){
@@ -17409,12 +19919,10 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
       register int nspace;
       nspace = width-length;
       if( nspace>0 ){
-        appendSpace(pAccum, nspace);
+        sqlite3AppendSpace(pAccum, nspace);
       }
     }
-    if( zExtra ){
-      sqlite3_free(zExtra);
-    }
+    sqlite3_free(zExtra);
   }/* End for loop over the format string */
 } /* End of function */
 
@@ -17422,13 +19930,17 @@ SQLITE_PRIVATE void sqlite3VXPrintf(
 ** Append N bytes of text from z to the StrAccum object.
 */
 SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
+  assert( z!=0 || N==0 );
   if( p->tooBig | p->mallocFailed ){
+    testcase(p->tooBig);
+    testcase(p->mallocFailed);
     return;
   }
+  assert( p->zText!=0 || p->nChar==0 );
   if( N<0 ){
     N = sqlite3Strlen30(z);
   }
-  if( N==0 || z==0 ){
+  if( N==0 || NEVER(z==0) ){
     return;
   }
   if( p->nChar+N >= p->nAlloc ){
@@ -17440,6 +19952,7 @@ SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
         return;
       }
     }else{
+      char *zOld = (p->zText==p->zBase ? 0 : p->zText);
       i64 szNew = p->nChar;
       szNew += N + 1;
       if( szNew > p->mxAlloc ){
@@ -17449,10 +19962,13 @@ SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
       }else{
         p->nAlloc = (int)szNew;
       }
-      zNew = sqlite3DbMallocRaw(p->db, p->nAlloc );
+      if( p->useMalloc==1 ){
+        zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
+      }else{
+        zNew = sqlite3_realloc(zOld, p->nAlloc);
+      }
       if( zNew ){
-        memcpy(zNew, p->zText, p->nChar);
-        sqlite3StrAccumReset(p);
+        if( zOld==0 && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
         p->zText = zNew;
       }else{
         p->mallocFailed = 1;
@@ -17461,6 +19977,7 @@ SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
       }
     }
   }
+  assert( p->zText );
   memcpy(&p->zText[p->nChar], z, N);
   p->nChar += N;
 }
@@ -17474,7 +19991,11 @@ SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum *p){
   if( p->zText ){
     p->zText[p->nChar] = 0;
     if( p->useMalloc && p->zText==p->zBase ){
-      p->zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
+      if( p->useMalloc==1 ){
+        p->zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
+      }else{
+        p->zText = sqlite3_malloc(p->nChar+1);
+      }
       if( p->zText ){
         memcpy(p->zText, p->zBase, p->nChar+1);
       }else{
@@ -17490,7 +20011,11 @@ SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum *p){
 */
 SQLITE_PRIVATE void sqlite3StrAccumReset(StrAccum *p){
   if( p->zText!=p->zBase ){
-    sqlite3DbFree(p->db, p->zText);
+    if( p->useMalloc==1 ){
+      sqlite3DbFree(p->db, p->zText);
+    }else{
+      sqlite3_free(p->zText);
+    }
   }
   p->zText = 0;
 }
@@ -17517,12 +20042,13 @@ SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list a
   char *z;
   char zBase[SQLITE_PRINT_BUF_SIZE];
   StrAccum acc;
+  assert( db!=0 );
   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase),
-                      db ? db->aLimit[SQLITE_LIMIT_LENGTH] : SQLITE_MAX_LENGTH);
+                      db->aLimit[SQLITE_LIMIT_LENGTH]);
   acc.db = db;
   sqlite3VXPrintf(&acc, 1, zFormat, ap);
   z = sqlite3StrAccumFinish(&acc);
-  if( acc.mallocFailed && db ){
+  if( acc.mallocFailed ){
     db->mallocFailed = 1;
   }
   return z;
@@ -17571,6 +20097,7 @@ SQLITE_API char *sqlite3_vmprintf(const char *zFormat, va_list ap){
   if( sqlite3_initialize() ) return 0;
 #endif
   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
+  acc.useMalloc = 2;
   sqlite3VXPrintf(&acc, 0, zFormat, ap);
   z = sqlite3StrAccumFinish(&acc);
   return z;
@@ -17597,24 +20124,63 @@ SQLITE_API char *sqlite3_mprintf(const char *zFormat, ...){
 ** current locale settings.  This is important for SQLite because we
 ** are not able to use a "," as the decimal point in place of "." as
 ** specified by some locales.
+**
+** Oops:  The first two arguments of sqlite3_snprintf() are backwards
+** from the snprintf() standard.  Unfortunately, it is too late to change
+** this without breaking compatibility, so we just have to live with the
+** mistake.
+**
+** sqlite3_vsnprintf() is the varargs version.
 */
+SQLITE_API char *sqlite3_vsnprintf(int n, char *zBuf, const char *zFormat, va_list ap){
+  StrAccum acc;
+  if( n<=0 ) return zBuf;
+  sqlite3StrAccumInit(&acc, zBuf, n, 0);
+  acc.useMalloc = 0;
+  sqlite3VXPrintf(&acc, 0, zFormat, ap);
+  return sqlite3StrAccumFinish(&acc);
+}
 SQLITE_API char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
   char *z;
   va_list ap;
-  StrAccum acc;
-
-  if( n<=0 ){
-    return zBuf;
-  }
-  sqlite3StrAccumInit(&acc, zBuf, n, 0);
-  acc.useMalloc = 0;
   va_start(ap,zFormat);
-  sqlite3VXPrintf(&acc, 0, zFormat, ap);
+  z = sqlite3_vsnprintf(n, zBuf, zFormat, ap);
   va_end(ap);
-  z = sqlite3StrAccumFinish(&acc);
   return z;
 }
 
+/*
+** This is the routine that actually formats the sqlite3_log() message.
+** We house it in a separate routine from sqlite3_log() to avoid using
+** stack space on small-stack systems when logging is disabled.
+**
+** sqlite3_log() must render into a static buffer.  It cannot dynamically
+** allocate memory because it might be called while the memory allocator
+** mutex is held.
+*/
+static void renderLogMsg(int iErrCode, const char *zFormat, va_list ap){
+  StrAccum acc;                          /* String accumulator */
+  char zMsg[SQLITE_PRINT_BUF_SIZE*3];    /* Complete log message */
+
+  sqlite3StrAccumInit(&acc, zMsg, sizeof(zMsg), 0);
+  acc.useMalloc = 0;
+  sqlite3VXPrintf(&acc, 0, zFormat, ap);
+  sqlite3GlobalConfig.xLog(sqlite3GlobalConfig.pLogArg, iErrCode,
+                           sqlite3StrAccumFinish(&acc));
+}
+
+/*
+** Format and write a message to the log if logging is enabled.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...){
+  va_list ap;                             /* Vararg list */
+  if( sqlite3GlobalConfig.xLog ){
+    va_start(ap, zFormat);
+    renderLogMsg(iErrCode, zFormat, ap);
+    va_end(ap);
+  }
+}
+
 #if defined(SQLITE_DEBUG)
 /*
 ** A version of printf() that understands %lld.  Used for debugging.
@@ -17636,6 +20202,18 @@ SQLITE_PRIVATE void sqlite3DebugPrintf(const char *zFormat, ...){
 }
 #endif
 
+#ifndef SQLITE_OMIT_TRACE
+/*
+** variable-argument wrapper around sqlite3VXPrintf().
+*/
+SQLITE_PRIVATE void sqlite3XPrintf(StrAccum *p, const char *zFormat, ...){
+  va_list ap;
+  va_start(ap,zFormat);
+  sqlite3VXPrintf(p, 1, zFormat, ap);
+  va_end(ap);
+}
+#endif
+
 /************** End of printf.c **********************************************/
 /************** Begin file random.c ******************************************/
 /*
@@ -17654,8 +20232,6 @@ SQLITE_PRIVATE void sqlite3DebugPrintf(const char *zFormat, ...){
 **
 ** Random numbers are used by some of the database backends in order
 ** to generate random integer keys for tables or random filenames.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
@@ -17801,8 +20377,6 @@ SQLITE_PRIVATE void sqlite3PrngResetState(void){
 ** This file contains routines used to translate between UTF-8, 
 ** UTF-16, UTF-16BE, and UTF-16LE.
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-**
 ** Notes on UTF-8:
 **
 **   Byte-0    Byte-1    Byte-2    Byte-3    Value
@@ -17824,412 +20398,7 @@ SQLITE_PRIVATE void sqlite3PrngResetState(void){
 **     0xfe 0xff   big-endian utf-16 follows
 **
 */
-/************** Include vdbeInt.h in the middle of utf.c *********************/
-/************** Begin file vdbeInt.h *****************************************/
-/*
-** 2003 September 6
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-*************************************************************************
-** This is the header file for information that is private to the
-** VDBE.  This information used to all be at the top of the single
-** source code file "vdbe.c".  When that file became too big (over
-** 6000 lines long) it was split up into several smaller files and
-** this header information was factored out.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-*/
-#ifndef _VDBEINT_H_
-#define _VDBEINT_H_
-
-/*
-** intToKey() and keyToInt() used to transform the rowid.  But with
-** the latest versions of the design they are no-ops.
-*/
-#define keyToInt(X)   (X)
-#define intToKey(X)   (X)
-
-
-/*
-** SQL is translated into a sequence of instructions to be
-** executed by a virtual machine.  Each instruction is an instance
-** of the following structure.
-*/
-typedef struct VdbeOp Op;
-
-/*
-** Boolean values
-*/
-typedef unsigned char Bool;
-
-/*
-** A cursor is a pointer into a single BTree within a database file.
-** The cursor can seek to a BTree entry with a particular key, or
-** loop over all entries of the Btree.  You can also insert new BTree
-** entries or retrieve the key or data from the entry that the cursor
-** is currently pointing to.
-** 
-** Every cursor that the virtual machine has open is represented by an
-** instance of the following structure.
-**
-** If the VdbeCursor.isTriggerRow flag is set it means that this cursor is
-** really a single row that represents the NEW or OLD pseudo-table of
-** a row trigger.  The data for the row is stored in VdbeCursor.pData and
-** the rowid is in VdbeCursor.iKey.
-*/
-struct VdbeCursor {
-  BtCursor *pCursor;    /* The cursor structure of the backend */
-  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */
-  i64 lastRowid;        /* Last rowid from a Next or NextIdx operation */
-  i64 nextRowid;        /* Next rowid returned by OP_NewRowid */
-  Bool zeroed;          /* True if zeroed out and ready for reuse */
-  Bool rowidIsValid;    /* True if lastRowid is valid */
-  Bool atFirst;         /* True if pointing to first entry */
-  Bool useRandomRowid;  /* Generate new record numbers semi-randomly */
-  Bool nullRow;         /* True if pointing to a row with no data */
-  Bool nextRowidValid;  /* True if the nextRowid field is valid */
-  Bool pseudoTable;     /* This is a NEW or OLD pseudo-tables of a trigger */
-  Bool ephemPseudoTable;
-  Bool deferredMoveto;  /* A call to sqlite3BtreeMoveto() is needed */
-  Bool isTable;         /* True if a table requiring integer keys */
-  Bool isIndex;         /* True if an index containing keys only - no data */
-  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
-  Btree *pBt;           /* Separate file holding temporary table */
-  int nData;            /* Number of bytes in pData */
-  char *pData;          /* Data for a NEW or OLD pseudo-table */
-  i64 iKey;             /* Key for the NEW or OLD pseudo-table row */
-  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */
-  int nField;           /* Number of fields in the header */
-  i64 seqCount;         /* Sequence counter */
-  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
-  const sqlite3_module *pModule;     /* Module for cursor pVtabCursor */
-
-  /* Cached information about the header for the data record that the
-  ** cursor is currently pointing to.  Only valid if cacheValid is true.
-  ** aRow might point to (ephemeral) data for the current row, or it might
-  ** be NULL.
-  */
-  int cacheStatus;      /* Cache is valid if this matches Vdbe.cacheCtr */
-  int payloadSize;      /* Total number of bytes in the record */
-  u32 *aType;           /* Type values for all entries in the record */
-  u32 *aOffset;         /* Cached offsets to the start of each columns data */
-  u8 *aRow;             /* Data for the current row, if all on one page */
-};
-typedef struct VdbeCursor VdbeCursor;
-
-/*
-** A value for VdbeCursor.cacheValid that means the cache is always invalid.
-*/
-#define CACHE_STALE 0
-
-/*
-** Internally, the vdbe manipulates nearly all SQL values as Mem
-** structures. Each Mem struct may cache multiple representations (string,
-** integer etc.) of the same value.  A value (and therefore Mem structure)
-** has the following properties:
-**
-** Each value has a manifest type. The manifest type of the value stored
-** in a Mem struct is returned by the MemType(Mem*) macro. The type is
-** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
-** SQLITE_BLOB.
-*/
-struct Mem {
-  union {
-    i64 i;              /* Integer value. */
-    int nZero;          /* Used when bit MEM_Zero is set in flags */
-    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
-    RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
-  } u;
-  double r;           /* Real value */
-  sqlite3 *db;        /* The associated database connection */
-  char *z;            /* String or BLOB value */
-  int n;              /* Number of characters in string value, excluding '\0' */
-  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
-  u8  type;           /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
-  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
-  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */
-  char *zMalloc;      /* Dynamic buffer allocated by sqlite3_malloc() */
-};
-
-/* One or more of the following flags are set to indicate the validOK
-** representations of the value stored in the Mem struct.
-**
-** If the MEM_Null flag is set, then the value is an SQL NULL value.
-** No other flags may be set in this case.
-**
-** If the MEM_Str flag is set then Mem.z points at a string representation.
-** Usually this is encoded in the same unicode encoding as the main
-** database (see below for exceptions). If the MEM_Term flag is also
-** set, then the string is nul terminated. The MEM_Int and MEM_Real 
-** flags may coexist with the MEM_Str flag.
-**
-** Multiple of these values can appear in Mem.flags.  But only one
-** at a time can appear in Mem.type.
-*/
-#define MEM_Null      0x0001   /* Value is NULL */
-#define MEM_Str       0x0002   /* Value is a string */
-#define MEM_Int       0x0004   /* Value is an integer */
-#define MEM_Real      0x0008   /* Value is a real number */
-#define MEM_Blob      0x0010   /* Value is a BLOB */
-#define MEM_RowSet    0x0020   /* Value is a RowSet object */
-#define MEM_TypeMask  0x00ff   /* Mask of type bits */
-
-/* Whenever Mem contains a valid string or blob representation, one of
-** the following flags must be set to determine the memory management
-** policy for Mem.z.  The MEM_Term flag tells us whether or not the
-** string is \000 or \u0000 terminated
-*/
-#define MEM_Term      0x0200   /* String rep is nul terminated */
-#define MEM_Dyn       0x0400   /* Need to call sqliteFree() on Mem.z */
-#define MEM_Static    0x0800   /* Mem.z points to a static string */
-#define MEM_Ephem     0x1000   /* Mem.z points to an ephemeral string */
-#define MEM_Agg       0x2000   /* Mem.z points to an agg function context */
-#define MEM_Zero      0x4000   /* Mem.i contains count of 0s appended to blob */
-
-#ifdef SQLITE_OMIT_INCRBLOB
-  #undef MEM_Zero
-  #define MEM_Zero 0x0000
-#endif
-
-
-/*
-** Clear any existing type flags from a Mem and replace them with f
-*/
-#define MemSetTypeFlag(p, f) \
-   ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f)
-
-
-/* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
-** additional information about auxiliary information bound to arguments
-** of the function.  This is used to implement the sqlite3_get_auxdata()
-** and sqlite3_set_auxdata() APIs.  The "auxdata" is some auxiliary data
-** that can be associated with a constant argument to a function.  This
-** allows functions such as "regexp" to compile their constant regular
-** expression argument once and reused the compiled code for multiple
-** invocations.
-*/
-struct VdbeFunc {
-  FuncDef *pFunc;               /* The definition of the function */
-  int nAux;                     /* Number of entries allocated for apAux[] */
-  struct AuxData {
-    void *pAux;                   /* Aux data for the i-th argument */
-    void (*xDelete)(void *);      /* Destructor for the aux data */
-  } apAux[1];                   /* One slot for each function argument */
-};
-
-/*
-** The "context" argument for a installable function.  A pointer to an
-** instance of this structure is the first argument to the routines used
-** implement the SQL functions.
-**
-** There is a typedef for this structure in sqlite.h.  So all routines,
-** even the public interface to SQLite, can use a pointer to this structure.
-** But this file is the only place where the internal details of this
-** structure are known.
-**
-** This structure is defined inside of vdbeInt.h because it uses substructures
-** (Mem) which are only defined there.
-*/
-struct sqlite3_context {
-  FuncDef *pFunc;       /* Pointer to function information.  MUST BE FIRST */
-  VdbeFunc *pVdbeFunc;  /* Auxilary data, if created. */
-  Mem s;                /* The return value is stored here */
-  Mem *pMem;            /* Memory cell used to store aggregate context */
-  int isError;          /* Error code returned by the function. */
-  CollSeq *pColl;       /* Collating sequence */
-};
-
-/*
-** A Set structure is used for quick testing to see if a value
-** is part of a small set.  Sets are used to implement code like
-** this:
-**            x.y IN ('hi','hoo','hum')
-*/
-typedef struct Set Set;
-struct Set {
-  Hash hash;             /* A set is just a hash table */
-  HashElem *prev;        /* Previously accessed hash elemen */
-};
-
-/*
-** A Context stores the last insert rowid, the last statement change count,
-** and the current statement change count (i.e. changes since last statement).
-** The current keylist is also stored in the context.
-** Elements of Context structure type make up the ContextStack, which is
-** updated by the ContextPush and ContextPop opcodes (used by triggers).
-** The context is pushed before executing a trigger a popped when the
-** trigger finishes.
-*/
-typedef struct Context Context;
-struct Context {
-  i64 lastRowid;    /* Last insert rowid (sqlite3.lastRowid) */
-  int nChange;      /* Statement changes (Vdbe.nChanges)     */
-};
-
-/*
-** An instance of the virtual machine.  This structure contains the complete
-** state of the virtual machine.
-**
-** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
-** is really a pointer to an instance of this structure.
-**
-** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
-** any virtual table method invocations made by the vdbe program. It is
-** set to 2 for xDestroy method calls and 1 for all other methods. This
-** variable is used for two purposes: to allow xDestroy methods to execute
-** "DROP TABLE" statements and to prevent some nasty side effects of
-** malloc failure when SQLite is invoked recursively by a virtual table 
-** method function.
-*/
-struct Vdbe {
-  sqlite3 *db;        /* The whole database */
-  Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
-  int nOp;            /* Number of instructions in the program */
-  int nOpAlloc;       /* Number of slots allocated for aOp[] */
-  Op *aOp;            /* Space to hold the virtual machine's program */
-  int nLabel;         /* Number of labels used */
-  int nLabelAlloc;    /* Number of slots allocated in aLabel[] */
-  int *aLabel;        /* Space to hold the labels */
-  Mem **apArg;        /* Arguments to currently executing user function */
-  Mem *aColName;      /* Column names to return */
-  int nCursor;        /* Number of slots in apCsr[] */
-  VdbeCursor **apCsr; /* One element of this array for each open cursor */
-  int nVar;           /* Number of entries in aVar[] */
-  Mem *aVar;          /* Values for the OP_Variable opcode. */
-  char **azVar;       /* Name of variables */
-  int okVar;          /* True if azVar[] has been initialized */
-  u32 magic;              /* Magic number for sanity checking */
-  int nMem;               /* Number of memory locations currently allocated */
-  Mem *aMem;              /* The memory locations */
-  int nCallback;          /* Number of callbacks invoked so far */
-  int cacheCtr;           /* VdbeCursor row cache generation counter */
-  int contextStackTop;    /* Index of top element in the context stack */
-  int contextStackDepth;  /* The size of the "context" stack */
-  Context *contextStack;  /* Stack used by opcodes ContextPush & ContextPop*/
-  int pc;                 /* The program counter */
-  int rc;                 /* Value to return */
-  unsigned uniqueCnt;     /* Used by OP_MakeRecord when P2!=0 */
-  int errorAction;        /* Recovery action to do in case of an error */
-  int inTempTrans;        /* True if temp database is transactioned */
-  int nResColumn;         /* Number of columns in one row of the result set */
-  char **azResColumn;     /* Values for one row of result */ 
-  char *zErrMsg;          /* Error message written here */
-  Mem *pResultSet;        /* Pointer to an array of results */
-  u8 explain;             /* True if EXPLAIN present on SQL command */
-  u8 changeCntOn;         /* True to update the change-counter */
-  u8 expired;             /* True if the VM needs to be recompiled */
-  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
-  u8 inVtabMethod;        /* See comments above */
-  u8 usesStmtJournal;     /* True if uses a statement journal */
-  u8 readOnly;            /* True for read-only statements */
-  int nChange;            /* Number of db changes made since last reset */
-  i64 startTime;          /* Time when query started - used for profiling */
-  int btreeMask;          /* Bitmask of db->aDb[] entries referenced */
-  BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
-  int aCounter[2];        /* Counters used by sqlite3_stmt_status() */
-  int nSql;             /* Number of bytes in zSql */
-  char *zSql;           /* Text of the SQL statement that generated this */
-#ifdef SQLITE_DEBUG
-  FILE *trace;          /* Write an execution trace here, if not NULL */
-#endif
-  int openedStatement;  /* True if this VM has opened a statement journal */
-#ifdef SQLITE_SSE
-  int fetchId;          /* Statement number used by sqlite3_fetch_statement */
-  int lru;              /* Counter used for LRU cache replacement */
-#endif
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
-  Vdbe *pLruPrev;
-  Vdbe *pLruNext;
-#endif
-};
-
-/*
-** The following are allowed values for Vdbe.magic
-*/
-#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */
-#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */
-#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */
-#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated */
-
-/*
-** Function prototypes
-*/
-SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*);
-void sqliteVdbePopStack(Vdbe*,int);
-SQLITE_PRIVATE int sqlite3VdbeCursorMoveto(VdbeCursor*);
-#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
-SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE*, int, Op*);
-#endif
-SQLITE_PRIVATE int sqlite3VdbeSerialTypeLen(u32);
-SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem*, int);
-SQLITE_PRIVATE int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
-SQLITE_PRIVATE int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
-SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
-
-int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
-SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*);
-SQLITE_PRIVATE int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
-SQLITE_PRIVATE int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
-SQLITE_PRIVATE int sqlite3VdbeExec(Vdbe*);
-SQLITE_PRIVATE int sqlite3VdbeList(Vdbe*);
-SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe*);
-SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *, int);
-SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem*, const Mem*);
-SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
-SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem*, Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
-SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem*, i64);
-SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem*, double);
-SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem*);
-SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem*,int);
-SQLITE_PRIVATE void sqlite3VdbeMemSetRowSet(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem*, int);
-SQLITE_PRIVATE i64 sqlite3VdbeIntValue(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem*);
-SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
-SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem*);
-SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
-SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
-SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p);
-SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
-SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
-SQLITE_PRIVATE int sqlite3VdbeOpcodeHasProperty(int, int);
-SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
-SQLITE_PRIVATE int sqlite3VdbeReleaseBuffers(Vdbe *p);
-#endif
-
-#ifndef NDEBUG
-SQLITE_PRIVATE   void sqlite3VdbeMemSanity(Mem*);
-#endif
-SQLITE_PRIVATE int sqlite3VdbeMemTranslate(Mem*, u8);
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE   void sqlite3VdbePrintSql(Vdbe*);
-SQLITE_PRIVATE   void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
-#endif
-SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem);
-
-#ifndef SQLITE_OMIT_INCRBLOB
-SQLITE_PRIVATE   int sqlite3VdbeMemExpandBlob(Mem *);
-#else
-  #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
-#endif
-
-#endif /* !defined(_VDBEINT_H_) */
-
-/************** End of vdbeInt.h *********************************************/
-/************** Continuing where we left off in utf.c ************************/
+/* #include <assert.h> */
 
 #ifndef SQLITE_AMALGAMATION
 /*
@@ -18299,25 +20468,23 @@ static const unsigned char sqlite3Utf8Trans1[] = {
   }                                                                 \
 }
 
-#define READ_UTF16LE(zIn, c){                                         \
+#define READ_UTF16LE(zIn, TERM, c){                                   \
   c = (*zIn++);                                                       \
   c += ((*zIn++)<<8);                                                 \
-  if( c>=0xD800 && c<0xE000 ){                                       \
+  if( c>=0xD800 && c<0xE000 && TERM ){                                \
     int c2 = (*zIn++);                                                \
     c2 += ((*zIn++)<<8);                                              \
     c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
-    if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \
   }                                                                   \
 }
 
-#define READ_UTF16BE(zIn, c){                                         \
+#define READ_UTF16BE(zIn, TERM, c){                                   \
   c = ((*zIn++)<<8);                                                  \
   c += (*zIn++);                                                      \
-  if( c>=0xD800 && c<0xE000 ){                                       \
+  if( c>=0xD800 && c<0xE000 && TERM ){                                \
     int c2 = ((*zIn++)<<8);                                           \
     c2 += (*zIn++);                                                   \
     c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
-    if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \
   }                                                                   \
 }
 
@@ -18359,14 +20526,26 @@ static const unsigned char sqlite3Utf8Trans1[] = {
         || (c&0xFFFFF800)==0xD800                          \
         || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
   }
-SQLITE_PRIVATE int sqlite3Utf8Read(
-  const unsigned char *z,         /* First byte of UTF-8 character */
-  const unsigned char *zTerm,     /* Pretend this byte is 0x00 */
+SQLITE_PRIVATE u32 sqlite3Utf8Read(
+  const unsigned char *zIn,       /* First byte of UTF-8 character */
   const unsigned char **pzNext    /* Write first byte past UTF-8 char here */
 ){
-  int c;
-  READ_UTF8(z, zTerm, c);
-  *pzNext = z;
+  unsigned int c;
+
+  /* Same as READ_UTF8() above but without the zTerm parameter.
+  ** For this routine, we assume the UTF8 string is always zero-terminated.
+  */
+  c = *(zIn++);
+  if( c>=0xc0 ){
+    c = sqlite3Utf8Trans1[c-0xc0];
+    while( (*zIn & 0xc0)==0x80 ){
+      c = (c<<6) + (0x3f & *(zIn++));
+    }
+    if( c<0x80
+        || (c&0xFFFFF800)==0xD800
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }
+  }
+  *pzNext = zIn;
   return c;
 }
 
@@ -18487,13 +20666,13 @@ SQLITE_PRIVATE int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
     if( pMem->enc==SQLITE_UTF16LE ){
       /* UTF-16 Little-endian -> UTF-8 */
       while( zIn<zTerm ){
-        READ_UTF16LE(zIn, c); 
+        READ_UTF16LE(zIn, zIn<zTerm, c); 
         WRITE_UTF8(z, c);
       }
     }else{
       /* UTF-16 Big-endian -> UTF-8 */
       while( zIn<zTerm ){
-        READ_UTF16BE(zIn, c); 
+        READ_UTF16BE(zIn, zIn<zTerm, c); 
         WRITE_UTF8(z, c);
       }
     }
@@ -18533,7 +20712,8 @@ SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem){
   int rc = SQLITE_OK;
   u8 bom = 0;
 
-  if( pMem->n<0 || pMem->n>1 ){
+  assert( pMem->n>=0 );
+  if( pMem->n>1 ){
     u8 b1 = *(u8 *)pMem->z;
     u8 b2 = *(((u8 *)pMem->z) + 1);
     if( b1==0xFE && b2==0xFF ){
@@ -18593,23 +20773,22 @@ SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *zIn, int nByte){
 ** This has the effect of making sure that the string is well-formed
 ** UTF-8.  Miscoded characters are removed.
 **
-** The translation is done in-place (since it is impossible for the
-** correct UTF-8 encoding to be longer than a malformed encoding).
+** The translation is done in-place and aborted if the output
+** overruns the input.
 */
 SQLITE_PRIVATE int sqlite3Utf8To8(unsigned char *zIn){
   unsigned char *zOut = zIn;
   unsigned char *zStart = zIn;
-  unsigned char *zTerm = &zIn[sqlite3Strlen30((char *)zIn)];
   u32 c;
 
-  while( zIn[0] ){
-    c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);
+  while( zIn[0] && zOut<=zIn ){
+    c = sqlite3Utf8Read(zIn, (const u8**)&zIn);
     if( c!=0xfffd ){
       WRITE_UTF8(zOut, c);
     }
   }
   *zOut = 0;
-  return zOut - zStart;
+  return (int)(zOut - zStart);
 }
 #endif
 
@@ -18621,11 +20800,11 @@ SQLITE_PRIVATE int sqlite3Utf8To8(unsigned char *zIn){
 **
 ** NULL is returned if there is an allocation error.
 */
-SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte){
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte, u8 enc){
   Mem m;
   memset(&m, 0, sizeof(m));
   m.db = db;
-  sqlite3VdbeMemSetStr(&m, z, nByte, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  sqlite3VdbeMemSetStr(&m, z, nByte, enc, SQLITE_STATIC);
   sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
   if( db->mallocFailed ){
     sqlite3VdbeMemRelease(&m);
@@ -18633,41 +20812,59 @@ SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte){
   }
   assert( (m.flags & MEM_Term)!=0 || db->mallocFailed );
   assert( (m.flags & MEM_Str)!=0 || db->mallocFailed );
-  return (m.flags & MEM_Dyn)!=0 ? m.z : sqlite3DbStrDup(db, m.z);
+  assert( (m.flags & MEM_Dyn)!=0 || db->mallocFailed );
+  assert( m.z || db->mallocFailed );
+  return m.z;
 }
 
 /*
-** pZ is a UTF-16 encoded unicode string. If nChar is less than zero,
-** return the number of bytes up to (but not including), the first pair
-** of consecutive 0x00 bytes in pZ. If nChar is not less than zero,
-** then return the number of bytes in the first nChar unicode characters
-** in pZ (or up until the first pair of 0x00 bytes, whichever comes first).
+** Convert a UTF-8 string to the UTF-16 encoding specified by parameter
+** enc. A pointer to the new string is returned, and the value of *pnOut
+** is set to the length of the returned string in bytes. The call should
+** arrange to call sqlite3DbFree() on the returned pointer when it is
+** no longer required.
+** 
+** If a malloc failure occurs, NULL is returned and the db.mallocFailed
+** flag set.
+*/
+#ifdef SQLITE_ENABLE_STAT3
+SQLITE_PRIVATE char *sqlite3Utf8to16(sqlite3 *db, u8 enc, char *z, int n, int *pnOut){
+  Mem m;
+  memset(&m, 0, sizeof(m));
+  m.db = db;
+  sqlite3VdbeMemSetStr(&m, z, n, SQLITE_UTF8, SQLITE_STATIC);
+  if( sqlite3VdbeMemTranslate(&m, enc) ){
+    assert( db->mallocFailed );
+    return 0;
+  }
+  assert( m.z==m.zMalloc );
+  *pnOut = m.n;
+  return m.z;
+}
+#endif
+
+/*
+** zIn is a UTF-16 encoded unicode string at least nChar characters long.
+** Return the number of bytes in the first nChar unicode characters
+** in pZ.  nChar must be non-negative.
 */
 SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *zIn, int nChar){
-  unsigned int c = 1;
-  char const *z = zIn;
+  int c;
+  unsigned char const *z = zIn;
   int n = 0;
+  
   if( SQLITE_UTF16NATIVE==SQLITE_UTF16BE ){
-    /* Using an "if (SQLITE_UTF16NATIVE==SQLITE_UTF16BE)" construct here
-    ** and in other parts of this file means that at one branch will
-    ** not be covered by coverage testing on any single host. But coverage
-    ** will be complete if the tests are run on both a little-endian and 
-    ** big-endian host. Because both the UTF16NATIVE and SQLITE_UTF16BE
-    ** macros are constant at compile time the compiler can determine
-    ** which branch will be followed. It is therefore assumed that no runtime
-    ** penalty is paid for this "if" statement.
-    */
-    while( c && ((nChar<0) || n<nChar) ){
-      READ_UTF16BE(z, c);
+    while( n<nChar ){
+      READ_UTF16BE(z, 1, c);
       n++;
     }
   }else{
-    while( c && ((nChar<0) || n<nChar) ){
-      READ_UTF16LE(z, c);
+    while( n<nChar ){
+      READ_UTF16LE(z, 1, c);
       n++;
     }
   }
-  return (int)(z-(char const *)zIn)-((c==0)?2:0);
+  return (int)(z-(unsigned char const *)zIn);
 }
 
 #if defined(SQLITE_TEST)
@@ -18680,7 +20877,6 @@ SQLITE_PRIVATE void sqlite3UtfSelfTest(void){
   unsigned int i, t;
   unsigned char zBuf[20];
   unsigned char *z;
-  unsigned char *zTerm;
   int n;
   unsigned int c;
 
@@ -18690,9 +20886,8 @@ SQLITE_PRIVATE void sqlite3UtfSelfTest(void){
     n = (int)(z-zBuf);
     assert( n>0 && n<=4 );
     z[0] = 0;
-    zTerm = z;
     z = zBuf;
-    c = sqlite3Utf8Read(z, zTerm, (const u8**)&z);
+    c = sqlite3Utf8Read(z, (const u8**)&z);
     t = i;
     if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;
     if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;
@@ -18707,7 +20902,7 @@ SQLITE_PRIVATE void sqlite3UtfSelfTest(void){
     assert( n>0 && n<=4 );
     z[0] = 0;
     z = zBuf;
-    READ_UTF16LE(z, c);
+    READ_UTF16LE(z, 1, c);
     assert( c==i );
     assert( (z-zBuf)==n );
   }
@@ -18719,7 +20914,7 @@ SQLITE_PRIVATE void sqlite3UtfSelfTest(void){
     assert( n>0 && n<=4 );
     z[0] = 0;
     z = zBuf;
-    READ_UTF16BE(z, c);
+    READ_UTF16BE(z, 1, c);
     assert( c==i );
     assert( (z-zBuf)==n );
   }
@@ -18745,46 +20940,39 @@ SQLITE_PRIVATE void sqlite3UtfSelfTest(void){
 ** This file contains functions for allocating memory, comparing
 ** strings, and stuff like that.
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
-
+/* #include <stdarg.h> */
+#ifdef SQLITE_HAVE_ISNAN
+# include <math.h>
+#endif
 
 /*
 ** Routine needed to support the testcase() macro.
 */
 #ifdef SQLITE_COVERAGE_TEST
 SQLITE_PRIVATE void sqlite3Coverage(int x){
-  static int dummy = 0;
-  dummy += x;
-}
-#endif
-
-/*
-** Routine needed to support the ALWAYS() and NEVER() macros.
-**
-** The argument to ALWAYS() should always be true and the argument
-** to NEVER() should always be false.  If either is not the case
-** then this routine is called in order to throw an error.
-**
-** This routine only exists if assert() is operational.  It always
-** throws an assert on its first invocation.  The variable has a long
-** name to help the assert() message be more readable.  The variable
-** is used to prevent a too-clever optimizer from optimizing out the
-** entire call.
-*/
-#ifndef NDEBUG
-SQLITE_PRIVATE int sqlite3Assert(void){
-  static volatile int ALWAYS_was_false_or_NEVER_was_true = 0;
-  assert( ALWAYS_was_false_or_NEVER_was_true );      /* Always fails */
-  return ALWAYS_was_false_or_NEVER_was_true++;       /* Not Reached */
+  static unsigned dummy = 0;
+  dummy += (unsigned)x;
 }
 #endif
 
+#ifndef SQLITE_OMIT_FLOATING_POINT
 /*
 ** Return true if the floating point value is Not a Number (NaN).
+**
+** Use the math library isnan() function if compiled with SQLITE_HAVE_ISNAN.
+** Otherwise, we have our own implementation that works on most systems.
 */
 SQLITE_PRIVATE int sqlite3IsNaN(double x){
-  /* This NaN test sometimes fails if compiled on GCC with -ffast-math.
+  int rc;   /* The value return */
+#if !defined(SQLITE_HAVE_ISNAN)
+  /*
+  ** Systems that support the isnan() library function should probably
+  ** make use of it by compiling with -DSQLITE_HAVE_ISNAN.  But we have
+  ** found that many systems do not have a working isnan() function so
+  ** this implementation is provided as an alternative.
+  **
+  ** This NaN test sometimes fails if compiled on GCC with -ffast-math.
   ** On the other hand, the use of -ffast-math comes with the following
   ** warning:
   **
@@ -18806,37 +20994,30 @@ SQLITE_PRIVATE int sqlite3IsNaN(double x){
 #endif
   volatile double y = x;
   volatile double z = y;
-  return y!=z;
+  rc = (y!=z);
+#else  /* if defined(SQLITE_HAVE_ISNAN) */
+  rc = isnan(x);
+#endif /* SQLITE_HAVE_ISNAN */
+  testcase( rc );
+  return rc;
 }
+#endif /* SQLITE_OMIT_FLOATING_POINT */
 
 /*
 ** Compute a string length that is limited to what can be stored in
 ** lower 30 bits of a 32-bit signed integer.
+**
+** The value returned will never be negative.  Nor will it ever be greater
+** than the actual length of the string.  For very long strings (greater
+** than 1GiB) the value returned might be less than the true string length.
 */
 SQLITE_PRIVATE int sqlite3Strlen30(const char *z){
   const char *z2 = z;
+  if( z==0 ) return 0;
   while( *z2 ){ z2++; }
   return 0x3fffffff & (int)(z2 - z);
 }
 
-/*
-** Return the length of a string, except do not allow the string length
-** to exceed the SQLITE_LIMIT_LENGTH setting.
-*/
-SQLITE_PRIVATE int sqlite3Strlen(sqlite3 *db, const char *z){
-  const char *z2 = z;
-  int len;
-  int x;
-  while( *z2 ){ z2++; }
-  x = (int)(z2 - z);
-  len = 0x7fffffff & x;
-  if( len!=x || len > db->aLimit[SQLITE_LIMIT_LENGTH] ){
-    return db->aLimit[SQLITE_LIMIT_LENGTH];
-  }else{
-    return len;
-  }
-}
-
 /*
 ** Set the most recent error code and error string for the sqlite
 ** handle "db". The error code is set to "err_code".
@@ -18892,62 +21073,65 @@ SQLITE_PRIVATE void sqlite3Error(sqlite3 *db, int err_code, const char *zFormat,
 ** (sqlite3_step() etc.).
 */
 SQLITE_PRIVATE void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
+  char *zMsg;
   va_list ap;
   sqlite3 *db = pParse->db;
-  pParse->nErr++;
-  sqlite3DbFree(db, pParse->zErrMsg);
   va_start(ap, zFormat);
-  pParse->zErrMsg = sqlite3VMPrintf(db, zFormat, ap);
+  zMsg = sqlite3VMPrintf(db, zFormat, ap);
   va_end(ap);
-  if( pParse->rc==SQLITE_OK ){
+  if( db->suppressErr ){
+    sqlite3DbFree(db, zMsg);
+  }else{
+    pParse->nErr++;
+    sqlite3DbFree(db, pParse->zErrMsg);
+    pParse->zErrMsg = zMsg;
     pParse->rc = SQLITE_ERROR;
   }
 }
 
-/*
-** Clear the error message in pParse, if any
-*/
-SQLITE_PRIVATE void sqlite3ErrorClear(Parse *pParse){
-  sqlite3DbFree(pParse->db, pParse->zErrMsg);
-  pParse->zErrMsg = 0;
-  pParse->nErr = 0;
-}
-
 /*
 ** Convert an SQL-style quoted string into a normal string by removing
 ** the quote characters.  The conversion is done in-place.  If the
 ** input does not begin with a quote character, then this routine
 ** is a no-op.
 **
+** The input string must be zero-terminated.  A new zero-terminator
+** is added to the dequoted string.
+**
+** The return value is -1 if no dequoting occurs or the length of the
+** dequoted string, exclusive of the zero terminator, if dequoting does
+** occur.
+**
 ** 2002-Feb-14: This routine is extended to remove MS-Access style
 ** brackets from around identifers.  For example:  "[a-b-c]" becomes
 ** "a-b-c".
 */
-SQLITE_PRIVATE void sqlite3Dequote(char *z){
+SQLITE_PRIVATE int sqlite3Dequote(char *z){
   char quote;
   int i, j;
-  if( z==0 ) return;
+  if( z==0 ) return -1;
   quote = z[0];
   switch( quote ){
     case '\'':  break;
     case '"':   break;
     case '`':   break;                /* For MySQL compatibility */
     case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
-    default:    return;
+    default:    return -1;
   }
-  for(i=1, j=0; z[i]; i++){
+  for(i=1, j=0; ALWAYS(z[i]); i++){
     if( z[i]==quote ){
       if( z[i+1]==quote ){
         z[j++] = quote;
         i++;
       }else{
-        z[j++] = 0;
         break;
       }
     }else{
       z[j++] = z[i];
     }
   }
+  z[j] = 0;
+  return j;
 }
 
 /* Convenient short-hand */
@@ -18956,15 +21140,21 @@ SQLITE_PRIVATE void sqlite3Dequote(char *z){
 /*
 ** Some systems have stricmp().  Others have strcasecmp().  Because
 ** there is no consistency, we will define our own.
+**
+** IMPLEMENTATION-OF: R-30243-02494 The sqlite3_stricmp() and
+** sqlite3_strnicmp() APIs allow applications and extensions to compare
+** the contents of two buffers containing UTF-8 strings in a
+** case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
 */
-SQLITE_PRIVATE int sqlite3StrICmp(const char *zLeft, const char *zRight){
+SQLITE_API int sqlite3_stricmp(const char *zLeft, const char *zRight){
   register unsigned char *a, *b;
   a = (unsigned char *)zLeft;
   b = (unsigned char *)zRight;
   while( *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
   return UpperToLower[*a] - UpperToLower[*b];
 }
-SQLITE_PRIVATE int sqlite3StrNICmp(const char *zLeft, const char *zRight, int N){
+SQLITE_API int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
   register unsigned char *a, *b;
   a = (unsigned char *)zLeft;
   b = (unsigned char *)zRight;
@@ -18973,120 +21163,179 @@ SQLITE_PRIVATE int sqlite3StrNICmp(const char *zLeft, const char *zRight, int N)
 }
 
 /*
-** Return TRUE if z is a pure numeric string.  Return FALSE if the
-** string contains any character which is not part of a number. If
-** the string is numeric and contains the '.' character, set *realnum
-** to TRUE (otherwise FALSE).
+** The string z[] is an text representation of a real number.
+** Convert this string to a double and write it into *pResult.
 **
-** An empty string is considered non-numeric.
+** The string z[] is length bytes in length (bytes, not characters) and
+** uses the encoding enc.  The string is not necessarily zero-terminated.
+**
+** Return TRUE if the result is a valid real number (or integer) and FALSE
+** if the string is empty or contains extraneous text.  Valid numbers
+** are in one of these formats:
+**
+**    [+-]digits[E[+-]digits]
+**    [+-]digits.[digits][E[+-]digits]
+**    [+-].digits[E[+-]digits]
+**
+** Leading and trailing whitespace is ignored for the purpose of determining
+** validity.
+**
+** If some prefix of the input string is a valid number, this routine
+** returns FALSE but it still converts the prefix and writes the result
+** into *pResult.
 */
-SQLITE_PRIVATE int sqlite3IsNumber(const char *z, int *realnum, u8 enc){
-  int incr = (enc==SQLITE_UTF8?1:2);
-  if( enc==SQLITE_UTF16BE ) z++;
-  if( *z=='-' || *z=='+' ) z += incr;
-  if( !isdigit(*(u8*)z) ){
-    return 0;
-  }
-  z += incr;
-  if( realnum ) *realnum = 0;
-  while( isdigit(*(u8*)z) ){ z += incr; }
-  if( *z=='.' ){
-    z += incr;
-    if( !isdigit(*(u8*)z) ) return 0;
-    while( isdigit(*(u8*)z) ){ z += incr; }
-    if( realnum ) *realnum = 1;
-  }
-  if( *z=='e' || *z=='E' ){
-    z += incr;
-    if( *z=='+' || *z=='-' ) z += incr;
-    if( !isdigit(*(u8*)z) ) return 0;
-    while( isdigit(*(u8*)z) ){ z += incr; }
-    if( realnum ) *realnum = 1;
-  }
-  return *z==0;
-}
-
-/*
-** The string z[] is an ascii representation of a real number.
-** Convert this string to a double.
-**
-** This routine assumes that z[] really is a valid number.  If it
-** is not, the result is undefined.
-**
-** This routine is used instead of the library atof() function because
-** the library atof() might want to use "," as the decimal point instead
-** of "." depending on how locale is set.  But that would cause problems
-** for SQL.  So this routine always uses "." regardless of locale.
-*/
-SQLITE_PRIVATE int sqlite3AtoF(const char *z, double *pResult){
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
 #ifndef SQLITE_OMIT_FLOATING_POINT
-  int sign = 1;
-  const char *zBegin = z;
-  LONGDOUBLE_TYPE v1 = 0.0;
-  int nSignificant = 0;
-  while( isspace(*(u8*)z) ) z++;
+  int incr = (enc==SQLITE_UTF8?1:2);
+  const char *zEnd = z + length;
+  /* sign * significand * (10 ^ (esign * exponent)) */
+  int sign = 1;    /* sign of significand */
+  i64 s = 0;       /* significand */
+  int d = 0;       /* adjust exponent for shifting decimal point */
+  int esign = 1;   /* sign of exponent */
+  int e = 0;       /* exponent */
+  int eValid = 1;  /* True exponent is either not used or is well-formed */
+  double result;
+  int nDigits = 0;
+
+  *pResult = 0.0;   /* Default return value, in case of an error */
+
+  if( enc==SQLITE_UTF16BE ) z++;
+
+  /* skip leading spaces */
+  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
+  if( z>=zEnd ) return 0;
+
+  /* get sign of significand */
   if( *z=='-' ){
     sign = -1;
-    z++;
+    z+=incr;
   }else if( *z=='+' ){
-    z++;
+    z+=incr;
   }
-  while( z[0]=='0' ){
-    z++;
-  }
-  while( isdigit(*(u8*)z) ){
-    v1 = v1*10.0 + (*z - '0');
-    z++;
-    nSignificant++;
+
+  /* skip leading zeroes */
+  while( z<zEnd && z[0]=='0' ) z+=incr, nDigits++;
+
+  /* copy max significant digits to significand */
+  while( z<zEnd && sqlite3Isdigit(*z) && s<((LARGEST_INT64-9)/10) ){
+    s = s*10 + (*z - '0');
+    z+=incr, nDigits++;
   }
+
+  /* skip non-significant significand digits
+  ** (increase exponent by d to shift decimal left) */
+  while( z<zEnd && sqlite3Isdigit(*z) ) z+=incr, nDigits++, d++;
+  if( z>=zEnd ) goto do_atof_calc;
+
+  /* if decimal point is present */
   if( *z=='.' ){
-    LONGDOUBLE_TYPE divisor = 1.0;
-    z++;
-    if( nSignificant==0 ){
-      while( z[0]=='0' ){
-        divisor *= 10.0;
-        z++;
-      }
+    z+=incr;
+    /* copy digits from after decimal to significand
+    ** (decrease exponent by d to shift decimal right) */
+    while( z<zEnd && sqlite3Isdigit(*z) && s<((LARGEST_INT64-9)/10) ){
+      s = s*10 + (*z - '0');
+      z+=incr, nDigits++, d--;
     }
-    while( isdigit(*(u8*)z) ){
-      if( nSignificant<18 ){
-        v1 = v1*10.0 + (*z - '0');
-        divisor *= 10.0;
-        nSignificant++;
-      }
-      z++;
-    }
-    v1 /= divisor;
+    /* skip non-significant digits */
+    while( z<zEnd && sqlite3Isdigit(*z) ) z+=incr, nDigits++;
   }
+  if( z>=zEnd ) goto do_atof_calc;
+
+  /* if exponent is present */
   if( *z=='e' || *z=='E' ){
-    int esign = 1;
-    int eval = 0;
-    LONGDOUBLE_TYPE scale = 1.0;
-    z++;
+    z+=incr;
+    eValid = 0;
+    if( z>=zEnd ) goto do_atof_calc;
+    /* get sign of exponent */
     if( *z=='-' ){
       esign = -1;
-      z++;
+      z+=incr;
     }else if( *z=='+' ){
-      z++;
+      z+=incr;
     }
-    while( isdigit(*(u8*)z) ){
-      eval = eval*10 + *z - '0';
-      z++;
-    }
-    while( eval>=64 ){ scale *= 1.0e+64; eval -= 64; }
-    while( eval>=16 ){ scale *= 1.0e+16; eval -= 16; }
-    while( eval>=4 ){ scale *= 1.0e+4; eval -= 4; }
-    while( eval>=1 ){ scale *= 1.0e+1; eval -= 1; }
-    if( esign<0 ){
-      v1 /= scale;
-    }else{
-      v1 *= scale;
+    /* copy digits to exponent */
+    while( z<zEnd && sqlite3Isdigit(*z) ){
+      e = e<10000 ? (e*10 + (*z - '0')) : 10000;
+      z+=incr;
+      eValid = 1;
     }
   }
-  *pResult = (double)(sign<0 ? -v1 : v1);
-  return (int)(z - zBegin);
+
+  /* skip trailing spaces */
+  if( nDigits && eValid ){
+    while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
+  }
+
+do_atof_calc:
+  /* adjust exponent by d, and update sign */
+  e = (e*esign) + d;
+  if( e<0 ) {
+    esign = -1;
+    e *= -1;
+  } else {
+    esign = 1;
+  }
+
+  /* if 0 significand */
+  if( !s ) {
+    /* In the IEEE 754 standard, zero is signed.
+    ** Add the sign if we've seen at least one digit */
+    result = (sign<0 && nDigits) ? -(double)0 : (double)0;
+  } else {
+    /* attempt to reduce exponent */
+    if( esign>0 ){
+      while( s<(LARGEST_INT64/10) && e>0 ) e--,s*=10;
+    }else{
+      while( !(s%10) && e>0 ) e--,s/=10;
+    }
+
+    /* adjust the sign of significand */
+    s = sign<0 ? -s : s;
+
+    /* if exponent, scale significand as appropriate
+    ** and store in result. */
+    if( e ){
+      LONGDOUBLE_TYPE scale = 1.0;
+      /* attempt to handle extremely small/large numbers better */
+      if( e>307 && e<342 ){
+        while( e%308 ) { scale *= 1.0e+1; e -= 1; }
+        if( esign<0 ){
+          result = s / scale;
+          result /= 1.0e+308;
+        }else{
+          result = s * scale;
+          result *= 1.0e+308;
+        }
+      }else if( e>=342 ){
+        if( esign<0 ){
+          result = 0.0*s;
+        }else{
+          result = 1e308*1e308*s;  /* Infinity */
+        }
+      }else{
+        /* 1.0e+22 is the largest power of 10 than can be 
+        ** represented exactly. */
+        while( e%22 ) { scale *= 1.0e+1; e -= 1; }
+        while( e>0 ) { scale *= 1.0e+22; e -= 22; }
+        if( esign<0 ){
+          result = s / scale;
+        }else{
+          result = s * scale;
+        }
+      }
+    } else {
+      result = (double)s;
+    }
+  }
+
+  /* store the result */
+  *pResult = result;
+
+  /* return true if number and no extra non-whitespace chracters after */
+  return z>=zEnd && nDigits>0 && eValid;
 #else
-  return sqlite3Atoi64(z, pResult);
+  return !sqlite3Atoi64(z, pResult, length, enc);
 #endif /* SQLITE_OMIT_FLOATING_POINT */
 }
 
@@ -19094,105 +21343,109 @@ SQLITE_PRIVATE int sqlite3AtoF(const char *z, double *pResult){
 ** Compare the 19-character string zNum against the text representation
 ** value 2^63:  9223372036854775808.  Return negative, zero, or positive
 ** if zNum is less than, equal to, or greater than the string.
+** Note that zNum must contain exactly 19 characters.
 **
 ** Unlike memcmp() this routine is guaranteed to return the difference
 ** in the values of the last digit if the only difference is in the
 ** last digit.  So, for example,
 **
-**      compare2pow63("9223372036854775800")
+**      compare2pow63("9223372036854775800", 1)
 **
 ** will return -8.
 */
-static int compare2pow63(const char *zNum){
-  int c;
-  c = memcmp(zNum,"922337203685477580",18);
+static int compare2pow63(const char *zNum, int incr){
+  int c = 0;
+  int i;
+                    /* 012345678901234567 */
+  const char *pow63 = "922337203685477580";
+  for(i=0; c==0 && i<18; i++){
+    c = (zNum[i*incr]-pow63[i])*10;
+  }
   if( c==0 ){
-    c = zNum[18] - '8';
+    c = zNum[18*incr] - '8';
+    testcase( c==(-1) );
+    testcase( c==0 );
+    testcase( c==(+1) );
   }
   return c;
 }
 
 
 /*
-** Return TRUE if zNum is a 64-bit signed integer and write
-** the value of the integer into *pNum.  If zNum is not an integer
-** or is an integer that is too large to be expressed with 64 bits,
-** then return false.
+** Convert zNum to a 64-bit signed integer.
 **
-** When this routine was originally written it dealt with only
-** 32-bit numbers.  At that time, it was much faster than the
-** atoi() library routine in RedHat 7.2.
+** If the zNum value is representable as a 64-bit twos-complement 
+** integer, then write that value into *pNum and return 0.
+**
+** If zNum is exactly 9223372036854665808, return 2.  This special
+** case is broken out because while 9223372036854665808 cannot be a 
+** signed 64-bit integer, its negative -9223372036854665808 can be.
+**
+** If zNum is too big for a 64-bit integer and is not
+** 9223372036854665808 then return 1.
+**
+** length is the number of bytes in the string (bytes, not characters).
+** The string is not necessarily zero-terminated.  The encoding is
+** given by enc.
 */
-SQLITE_PRIVATE int sqlite3Atoi64(const char *zNum, i64 *pNum){
-  i64 v = 0;
-  int neg;
-  int i, c;
+SQLITE_PRIVATE int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
+  int incr = (enc==SQLITE_UTF8?1:2);
+  u64 u = 0;
+  int neg = 0; /* assume positive */
+  int i;
+  int c = 0;
   const char *zStart;
-  while( isspace(*(u8*)zNum) ) zNum++;
-  if( *zNum=='-' ){
-    neg = 1;
-    zNum++;
-  }else if( *zNum=='+' ){
-    neg = 0;
-    zNum++;
-  }else{
-    neg = 0;
+  const char *zEnd = zNum + length;
+  if( enc==SQLITE_UTF16BE ) zNum++;
+  while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
+  if( zNum<zEnd ){
+    if( *zNum=='-' ){
+      neg = 1;
+      zNum+=incr;
+    }else if( *zNum=='+' ){
+      zNum+=incr;
+    }
   }
   zStart = zNum;
-  while( zNum[0]=='0' ){ zNum++; } /* Skip over leading zeros. Ticket #2454 */
-  for(i=0; (c=zNum[i])>='0' && c<='9'; i++){
-    v = v*10 + c - '0';
+  while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
+  for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
+    u = u*10 + c - '0';
   }
-  *pNum = neg ? -v : v;
-  if( c!=0 || (i==0 && zStart==zNum) || i>19 ){
+  if( u>LARGEST_INT64 ){
+    *pNum = SMALLEST_INT64;
+  }else if( neg ){
+    *pNum = -(i64)u;
+  }else{
+    *pNum = (i64)u;
+  }
+  testcase( i==18 );
+  testcase( i==19 );
+  testcase( i==20 );
+  if( (c!=0 && &zNum[i]<zEnd) || (i==0 && zStart==zNum) || i>19*incr ){
     /* zNum is empty or contains non-numeric text or is longer
-    ** than 19 digits (thus guaranting that it is too large) */
-    return 0;
-  }else if( i<19 ){
+    ** than 19 digits (thus guaranteeing that it is too large) */
+    return 1;
+  }else if( i<19*incr ){
     /* Less than 19 digits, so we know that it fits in 64 bits */
-    return 1;
-  }else{
-    /* 19-digit numbers must be no larger than 9223372036854775807 if positive
-    ** or 9223372036854775808 if negative.  Note that 9223372036854665808
-    ** is 2^63. */
-    return compare2pow63(zNum)<neg;
-  }
-}
-
-/*
-** The string zNum represents an integer.  There might be some other
-** information following the integer too, but that part is ignored.
-** If the integer that the prefix of zNum represents will fit in a
-** 64-bit signed integer, return TRUE.  Otherwise return FALSE.
-**
-** This routine returns FALSE for the string -9223372036854775808 even that
-** that number will, in theory fit in a 64-bit integer.  Positive
-** 9223373036854775808 will not fit in 64 bits.  So it seems safer to return
-** false.
-*/
-SQLITE_PRIVATE int sqlite3FitsIn64Bits(const char *zNum, int negFlag){
-  int i, c;
-  int neg = 0;
-  if( *zNum=='-' ){
-    neg = 1;
-    zNum++;
-  }else if( *zNum=='+' ){
-    zNum++;
-  }
-  if( negFlag ) neg = 1-neg;
-  while( *zNum=='0' ){
-    zNum++;   /* Skip leading zeros.  Ticket #2454 */
-  }
-  for(i=0; (c=zNum[i])>='0' && c<='9'; i++){}
-  if( i<19 ){
-    /* Guaranteed to fit if less than 19 digits */
-    return 1;
-  }else if( i>19 ){
-    /* Guaranteed to be too big if greater than 19 digits */
+    assert( u<=LARGEST_INT64 );
     return 0;
   }else{
-    /* Compare against 2^63. */
-    return compare2pow63(zNum)<neg;
+    /* zNum is a 19-digit numbers.  Compare it against 9223372036854775808. */
+    c = compare2pow63(zNum, incr);
+    if( c<0 ){
+      /* zNum is less than 9223372036854775808 so it fits */
+      assert( u<=LARGEST_INT64 );
+      return 0;
+    }else if( c>0 ){
+      /* zNum is greater than 9223372036854775808 so it overflows */
+      return 1;
+    }else{
+      /* zNum is exactly 9223372036854775808.  Fits if negative.  The
+      ** special case 2 overflow if positive */
+      assert( u-1==LARGEST_INT64 );
+      assert( (*pNum)==SMALLEST_INT64 );
+      return neg ? 0 : 2;
+    }
   }
 }
 
@@ -19224,9 +21477,11 @@ SQLITE_PRIVATE int sqlite3GetInt32(const char *zNum, int *pValue){
   **             1234567890
   **     2^31 -> 2147483648
   */
+  testcase( i==10 );
   if( i>10 ){
     return 0;
   }
+  testcase( v-neg==2147483647 );
   if( v-neg>2147483647 ){
     return 0;
   }
@@ -19237,6 +21492,16 @@ SQLITE_PRIVATE int sqlite3GetInt32(const char *zNum, int *pValue){
   return 1;
 }
 
+/*
+** Return a 32-bit integer value extracted from a string.  If the
+** string is not an integer, just return 0.
+*/
+SQLITE_PRIVATE int sqlite3Atoi(const char *z){
+  int x = 0;
+  if( z ) sqlite3GetInt32(z, &x);
+  return x;
+}
+
 /*
 ** The variable-length integer encoding is as follows:
 **
@@ -19314,6 +21579,19 @@ SQLITE_PRIVATE int sqlite3PutVarint32(unsigned char *p, u32 v){
   return sqlite3PutVarint(p, v);
 }
 
+/*
+** Bitmasks used by sqlite3GetVarint().  These precomputed constants
+** are defined here rather than simply putting the constant expressions
+** inline in order to work around bugs in the RVT compiler.
+**
+** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
+**
+** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
+*/
+#define SLOT_2_0     0x001fc07f
+#define SLOT_4_2_0   0xf01fc07f
+
+
 /*
 ** Read a 64-bit variable-length integer from memory starting at p[0].
 ** Return the number of bytes read.  The value is stored in *v.
@@ -19341,13 +21619,17 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
     return 2;
   }
 
+  /* Verify that constants are precomputed correctly */
+  assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
+  assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
+
   p++;
   a = a<<14;
   a |= *p;
   /* a: p0<<14 | p2 (unmasked) */
   if (!(a&0x80))
   {
-    a &= (0x7f<<14)|(0x7f);
+    a &= SLOT_2_0;
     b &= 0x7f;
     b = b<<7;
     a |= b;
@@ -19356,14 +21638,14 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
   }
 
   /* CSE1 from below */
-  a &= (0x7f<<14)|(0x7f);
+  a &= SLOT_2_0;
   p++;
   b = b<<14;
   b |= *p;
   /* b: p1<<14 | p3 (unmasked) */
   if (!(b&0x80))
   {
-    b &= (0x7f<<14)|(0x7f);
+    b &= SLOT_2_0;
     /* moved CSE1 up */
     /* a &= (0x7f<<14)|(0x7f); */
     a = a<<7;
@@ -19377,7 +21659,7 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
   /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
   /* moved CSE1 up */
   /* a &= (0x7f<<14)|(0x7f); */
-  b &= (0x7f<<14)|(0x7f);
+  b &= SLOT_2_0;
   s = a;
   /* s: p0<<14 | p2 (masked) */
 
@@ -19410,7 +21692,7 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
   {
     /* we can skip this cause it was (effectively) done above in calc'ing s */
     /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
-    a &= (0x7f<<14)|(0x7f);
+    a &= SLOT_2_0;
     a = a<<7;
     a |= b;
     s = s>>18;
@@ -19424,8 +21706,8 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
   /* a: p2<<28 | p4<<14 | p6 (unmasked) */
   if (!(a&0x80))
   {
-    a &= (0x7f<<28)|(0x7f<<14)|(0x7f);
-    b &= (0x7f<<14)|(0x7f);
+    a &= SLOT_4_2_0;
+    b &= SLOT_2_0;
     b = b<<7;
     a |= b;
     s = s>>11;
@@ -19434,14 +21716,14 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
   }
 
   /* CSE2 from below */
-  a &= (0x7f<<14)|(0x7f);
+  a &= SLOT_2_0;
   p++;
   b = b<<14;
   b |= *p;
   /* b: p3<<28 | p5<<14 | p7 (unmasked) */
   if (!(b&0x80))
   {
-    b &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+    b &= SLOT_4_2_0;
     /* moved CSE2 up */
     /* a &= (0x7f<<14)|(0x7f); */
     a = a<<7;
@@ -19458,7 +21740,7 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
 
   /* moved CSE2 up */
   /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
-  b &= (0x7f<<14)|(0x7f);
+  b &= SLOT_2_0;
   b = b<<8;
   a |= b;
 
@@ -19476,6 +21758,10 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
 /*
 ** Read a 32-bit variable-length integer from memory starting at p[0].
 ** Return the number of bytes read.  The value is stored in *v.
+**
+** If the varint stored in p[0] is larger than can fit in a 32-bit unsigned
+** integer, then set *v to 0xffffffff.
+**
 ** A MACRO version, getVarint32, is provided which inlines the 
 ** single-byte case.  All code should use the MACRO version as 
 ** this function assumes the single-byte case has already been handled.
@@ -19483,33 +21769,40 @@ SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
 SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
   u32 a,b;
 
+  /* The 1-byte case.  Overwhelmingly the most common.  Handled inline
+  ** by the getVarin32() macro */
   a = *p;
   /* a: p0 (unmasked) */
 #ifndef getVarint32
   if (!(a&0x80))
   {
+    /* Values between 0 and 127 */
     *v = a;
     return 1;
   }
 #endif
 
+  /* The 2-byte case */
   p++;
   b = *p;
   /* b: p1 (unmasked) */
   if (!(b&0x80))
   {
+    /* Values between 128 and 16383 */
     a &= 0x7f;
     a = a<<7;
     *v = a | b;
     return 2;
   }
 
+  /* The 3-byte case */
   p++;
   a = a<<14;
   a |= *p;
   /* a: p0<<14 | p2 (unmasked) */
   if (!(a&0x80))
   {
+    /* Values between 16384 and 2097151 */
     a &= (0x7f<<14)|(0x7f);
     b &= 0x7f;
     b = b<<7;
@@ -19517,12 +21810,43 @@ SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
     return 3;
   }
 
+  /* A 32-bit varint is used to store size information in btrees.
+  ** Objects are rarely larger than 2MiB limit of a 3-byte varint.
+  ** A 3-byte varint is sufficient, for example, to record the size
+  ** of a 1048569-byte BLOB or string.
+  **
+  ** We only unroll the first 1-, 2-, and 3- byte cases.  The very
+  ** rare larger cases can be handled by the slower 64-bit varint
+  ** routine.
+  */
+#if 1
+  {
+    u64 v64;
+    u8 n;
+
+    p -= 2;
+    n = sqlite3GetVarint(p, &v64);
+    assert( n>3 && n<=9 );
+    if( (v64 & SQLITE_MAX_U32)!=v64 ){
+      *v = 0xffffffff;
+    }else{
+      *v = (u32)v64;
+    }
+    return n;
+  }
+
+#else
+  /* For following code (kept for historical record only) shows an
+  ** unrolling for the 3- and 4-byte varint cases.  This code is
+  ** slightly faster, but it is also larger and much harder to test.
+  */
   p++;
   b = b<<14;
   b |= *p;
   /* b: p1<<14 | p3 (unmasked) */
   if (!(b&0x80))
   {
+    /* Values between 2097152 and 268435455 */
     b &= (0x7f<<14)|(0x7f);
     a &= (0x7f<<14)|(0x7f);
     a = a<<7;
@@ -19536,8 +21860,9 @@ SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
   /* a: p0<<28 | p2<<14 | p4 (unmasked) */
   if (!(a&0x80))
   {
-    a &= (0x7f<<28)|(0x7f<<14)|(0x7f);
-    b &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+    /* Values  between 268435456 and 34359738367 */
+    a &= SLOT_4_2_0;
+    b &= SLOT_4_2_0;
     b = b<<7;
     *v = a | b;
     return 5;
@@ -19557,6 +21882,7 @@ SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
     *v = (u32)v64;
     return n;
   }
+#endif
 }
 
 /*
@@ -19568,7 +21894,7 @@ SQLITE_PRIVATE int sqlite3VarintLen(u64 v){
   do{
     i++;
     v >>= 7;
-  }while( v!=0 && i<9 );
+  }while( v!=0 && ALWAYS(i<9) );
   return i;
 }
 
@@ -19588,13 +21914,12 @@ SQLITE_PRIVATE void sqlite3Put4byte(unsigned char *p, u32 v){
 
 
 
-#if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
 /*
 ** Translate a single byte of Hex into an integer.
-** This routinen only works if h really is a valid hexadecimal
+** This routine only works if h really is a valid hexadecimal
 ** character:  0..9a..fA..F
 */
-static u8 hexToInt(int h){
+SQLITE_PRIVATE u8 sqlite3HexToInt(int h){
   assert( (h>='0' && h<='9') ||  (h>='a' && h<='f') ||  (h>='A' && h<='F') );
 #ifdef SQLITE_ASCII
   h += 9*(1&(h>>6));
@@ -19604,7 +21929,6 @@ static u8 hexToInt(int h){
 #endif
   return (u8)(h & 0xf);
 }
-#endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
 
 #if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
 /*
@@ -19621,7 +21945,7 @@ SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
   n--;
   if( zBlob ){
     for(i=0; i<n; i+=2){
-      zBlob[i/2] = (hexToInt(z[i])<<4) | hexToInt(z[i+1]);
+      zBlob[i/2] = (sqlite3HexToInt(z[i])<<4) | sqlite3HexToInt(z[i+1]);
     }
     zBlob[i/2] = 0;
   }
@@ -19629,64 +21953,17 @@ SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
 }
 #endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
 
-
 /*
-** Change the sqlite.magic from SQLITE_MAGIC_OPEN to SQLITE_MAGIC_BUSY.
-** Return an error (non-zero) if the magic was not SQLITE_MAGIC_OPEN
-** when this routine is called.
-**
-** This routine is called when entering an SQLite API.  The SQLITE_MAGIC_OPEN
-** value indicates that the database connection passed into the API is
-** open and is not being used by another thread.  By changing the value
-** to SQLITE_MAGIC_BUSY we indicate that the connection is in use.
-** sqlite3SafetyOff() below will change the value back to SQLITE_MAGIC_OPEN
-** when the API exits. 
-**
-** This routine is a attempt to detect if two threads use the
-** same sqlite* pointer at the same time.  There is a race 
-** condition so it is possible that the error is not detected.
-** But usually the problem will be seen.  The result will be an
-** error which can be used to debug the application that is
-** using SQLite incorrectly.
-**
-** Ticket #202:  If db->magic is not a valid open value, take care not
-** to modify the db structure at all.  It could be that db is a stale
-** pointer.  In other words, it could be that there has been a prior
-** call to sqlite3_close(db) and db has been deallocated.  And we do
-** not want to write into deallocated memory.
+** Log an error that is an API call on a connection pointer that should
+** not have been used.  The "type" of connection pointer is given as the
+** argument.  The zType is a word like "NULL" or "closed" or "invalid".
 */
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE int sqlite3SafetyOn(sqlite3 *db){
-  if( db->magic==SQLITE_MAGIC_OPEN ){
-    db->magic = SQLITE_MAGIC_BUSY;
-    assert( sqlite3_mutex_held(db->mutex) );
-    return 0;
-  }else if( db->magic==SQLITE_MAGIC_BUSY ){
-    db->magic = SQLITE_MAGIC_ERROR;
-    db->u1.isInterrupted = 1;
-  }
-  return 1;
+static void logBadConnection(const char *zType){
+  sqlite3_log(SQLITE_MISUSE, 
+     "API call with %s database connection pointer",
+     zType
+  );
 }
-#endif
-
-/*
-** Change the magic from SQLITE_MAGIC_BUSY to SQLITE_MAGIC_OPEN.
-** Return an error (non-zero) if the magic was not SQLITE_MAGIC_BUSY
-** when this routine is called.
-*/
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE int sqlite3SafetyOff(sqlite3 *db){
-  if( db->magic==SQLITE_MAGIC_BUSY ){
-    db->magic = SQLITE_MAGIC_OPEN;
-    assert( sqlite3_mutex_held(db->mutex) );
-    return 0;
-  }else{
-    db->magic = SQLITE_MAGIC_ERROR;
-    db->u1.isInterrupted = 1;
-    return 1;
-  }
-}
-#endif
 
 /*
 ** Check to make sure we have a valid db pointer.  This test is not
@@ -19704,22 +21981,134 @@ SQLITE_PRIVATE int sqlite3SafetyOff(sqlite3 *db){
 */
 SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3 *db){
   u32 magic;
-  if( db==0 ) return 0;
+  if( db==0 ){
+    logBadConnection("NULL");
+    return 0;
+  }
   magic = db->magic;
-  if( magic!=SQLITE_MAGIC_OPEN &&
-      magic!=SQLITE_MAGIC_BUSY ) return 0;
-  return 1;
+  if( magic!=SQLITE_MAGIC_OPEN ){
+    if( sqlite3SafetyCheckSickOrOk(db) ){
+      testcase( sqlite3GlobalConfig.xLog!=0 );
+      logBadConnection("unopened");
+    }
+    return 0;
+  }else{
+    return 1;
+  }
 }
 SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
   u32 magic;
-  if( db==0 ) return 0;
   magic = db->magic;
   if( magic!=SQLITE_MAGIC_SICK &&
       magic!=SQLITE_MAGIC_OPEN &&
-      magic!=SQLITE_MAGIC_BUSY ) return 0;
-  return 1;
+      magic!=SQLITE_MAGIC_BUSY ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    logBadConnection("invalid");
+    return 0;
+  }else{
+    return 1;
+  }
 }
 
+/*
+** Attempt to add, substract, or multiply the 64-bit signed value iB against
+** the other 64-bit signed integer at *pA and store the result in *pA.
+** Return 0 on success.  Or if the operation would have resulted in an
+** overflow, leave *pA unchanged and return 1.
+*/
+SQLITE_PRIVATE int sqlite3AddInt64(i64 *pA, i64 iB){
+  i64 iA = *pA;
+  testcase( iA==0 ); testcase( iA==1 );
+  testcase( iB==-1 ); testcase( iB==0 );
+  if( iB>=0 ){
+    testcase( iA>0 && LARGEST_INT64 - iA == iB );
+    testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
+    if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
+    *pA += iB;
+  }else{
+    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
+    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
+    if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
+    *pA += iB;
+  }
+  return 0; 
+}
+SQLITE_PRIVATE int sqlite3SubInt64(i64 *pA, i64 iB){
+  testcase( iB==SMALLEST_INT64+1 );
+  if( iB==SMALLEST_INT64 ){
+    testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
+    if( (*pA)>=0 ) return 1;
+    *pA -= iB;
+    return 0;
+  }else{
+    return sqlite3AddInt64(pA, -iB);
+  }
+}
+#define TWOPOWER32 (((i64)1)<<32)
+#define TWOPOWER31 (((i64)1)<<31)
+SQLITE_PRIVATE int sqlite3MulInt64(i64 *pA, i64 iB){
+  i64 iA = *pA;
+  i64 iA1, iA0, iB1, iB0, r;
+
+  iA1 = iA/TWOPOWER32;
+  iA0 = iA % TWOPOWER32;
+  iB1 = iB/TWOPOWER32;
+  iB0 = iB % TWOPOWER32;
+  if( iA1*iB1 != 0 ) return 1;
+  assert( iA1*iB0==0 || iA0*iB1==0 );
+  r = iA1*iB0 + iA0*iB1;
+  testcase( r==(-TWOPOWER31)-1 );
+  testcase( r==(-TWOPOWER31) );
+  testcase( r==TWOPOWER31 );
+  testcase( r==TWOPOWER31-1 );
+  if( r<(-TWOPOWER31) || r>=TWOPOWER31 ) return 1;
+  r *= TWOPOWER32;
+  if( sqlite3AddInt64(&r, iA0*iB0) ) return 1;
+  *pA = r;
+  return 0;
+}
+
+/*
+** Compute the absolute value of a 32-bit signed integer, of possible.  Or 
+** if the integer has a value of -2147483648, return +2147483647
+*/
+SQLITE_PRIVATE int sqlite3AbsInt32(int x){
+  if( x>=0 ) return x;
+  if( x==(int)0x80000000 ) return 0x7fffffff;
+  return -x;
+}
+
+#ifdef SQLITE_ENABLE_8_3_NAMES
+/*
+** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
+** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
+** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
+** three characters, then shorten the suffix on z[] to be the last three
+** characters of the original suffix.
+**
+** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
+** do the suffix shortening regardless of URI parameter.
+**
+** Examples:
+**
+**     test.db-journal    =>   test.nal
+**     test.db-wal        =>   test.wal
+**     test.db-shm        =>   test.shm
+**     test.db-mj7f3319fa =>   test.9fa
+*/
+SQLITE_PRIVATE void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
+#if SQLITE_ENABLE_8_3_NAMES<2
+  if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
+#endif
+  {
+    int i, sz;
+    sz = sqlite3Strlen30(z);
+    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
+    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
+  }
+}
+#endif
+
 /************** End of util.c ************************************************/
 /************** Begin file hash.c ********************************************/
 /*
@@ -19735,20 +22124,16 @@ SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
 *************************************************************************
 ** This is the implementation of generic hash-tables
 ** used in SQLite.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/* #include <assert.h> */
 
 /* Turn bulk memory into a hash table object by initializing the
 ** fields of the Hash structure.
 **
 ** "pNew" is a pointer to the hash table that is to be initialized.
-** "copyKey" is true if the hash table should make its own private
-** copy of keys and false if it should just use the supplied pointer.
 */
-SQLITE_PRIVATE void sqlite3HashInit(Hash *pNew, int copyKey){
+SQLITE_PRIVATE void sqlite3HashInit(Hash *pNew){
   assert( pNew!=0 );
-  pNew->copyKey = copyKey!=0;
   pNew->first = 0;
   pNew->count = 0;
   pNew->htsize = 0;
@@ -19770,9 +22155,6 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash *pH){
   pH->htsize = 0;
   while( elem ){
     HashElem *next_elem = elem->next;
-    if( pH->copyKey ){
-      sqlite3_free(elem->pKey);
-    }
     sqlite3_free(elem);
     elem = next_elem;
   }
@@ -19780,25 +22162,21 @@ SQLITE_PRIVATE void sqlite3HashClear(Hash *pH){
 }
 
 /*
-** Hash and comparison functions when the mode is SQLITE_HASH_STRING
+** The hashing function.
 */
-static int strHash(const void *pKey, int nKey){
-  const char *z = (const char *)pKey;
+static unsigned int strHash(const char *z, int nKey){
   int h = 0;
-  if( nKey<=0 ) nKey = sqlite3Strlen30(z);
+  assert( nKey>=0 );
   while( nKey > 0  ){
     h = (h<<3) ^ h ^ sqlite3UpperToLower[(unsigned char)*z++];
     nKey--;
   }
-  return h & 0x7fffffff;
-}
-static int strCompare(const void *pKey1, int n1, const void *pKey2, int n2){
-  if( n1!=n2 ) return 1;
-  return sqlite3StrNICmp((const char*)pKey1,(const char*)pKey2,n1);
+  return h;
 }
 
 
-/* Link an element into the hash table
+/* Link pNew element into the hash table pH.  If pEntry!=0 then also
+** insert pNew into the pEntry hash bucket.
 */
 static void insertElement(
   Hash *pH,              /* The complete hash table */
@@ -19806,7 +22184,13 @@ static void insertElement(
   HashElem *pNew         /* The element to be inserted */
 ){
   HashElem *pHead;       /* First element already in pEntry */
-  pHead = pEntry->chain;
+  if( pEntry ){
+    pHead = pEntry->count ? pEntry->chain : 0;
+    pEntry->count++;
+    pEntry->chain = pNew;
+  }else{
+    pHead = 0;
+  }
   if( pHead ){
     pNew->next = pHead;
     pNew->prev = pHead->prev;
@@ -19819,44 +22203,49 @@ static void insertElement(
     pNew->prev = 0;
     pH->first = pNew;
   }
-  pEntry->count++;
-  pEntry->chain = pNew;
 }
 
 
 /* Resize the hash table so that it cantains "new_size" buckets.
-** "new_size" must be a power of 2.  The hash table might fail 
-** to resize if sqlite3_malloc() fails.
+**
+** The hash table might fail to resize if sqlite3_malloc() fails or
+** if the new size is the same as the prior size.
+** Return TRUE if the resize occurs and false if not.
 */
-static void rehash(Hash *pH, int new_size){
+static int rehash(Hash *pH, unsigned int new_size){
   struct _ht *new_ht;            /* The new hash table */
   HashElem *elem, *next_elem;    /* For looping over existing elements */
 
-#ifdef SQLITE_MALLOC_SOFT_LIMIT
+#if SQLITE_MALLOC_SOFT_LIMIT>0
   if( new_size*sizeof(struct _ht)>SQLITE_MALLOC_SOFT_LIMIT ){
     new_size = SQLITE_MALLOC_SOFT_LIMIT/sizeof(struct _ht);
   }
-  if( new_size==pH->htsize ) return;
+  if( new_size==pH->htsize ) return 0;
 #endif
 
-  /* There is a call to sqlite3_malloc() inside rehash(). If there is
-  ** already an allocation at pH->ht, then if this malloc() fails it
-  ** is benign (since failing to resize a hash table is a performance
-  ** hit only, not a fatal error).
+  /* The inability to allocates space for a larger hash table is
+  ** a performance hit but it is not a fatal error.  So mark the
+  ** allocation as a benign. Use sqlite3Malloc()/memset(0) instead of 
+  ** sqlite3MallocZero() to make the allocation, as sqlite3MallocZero()
+  ** only zeroes the requested number of bytes whereas this module will
+  ** use the actual amount of space allocated for the hash table (which
+  ** may be larger than the requested amount).
   */
-  if( pH->htsize>0 ) sqlite3BeginBenignMalloc();
-  new_ht = (struct _ht *)sqlite3MallocZero( new_size*sizeof(struct _ht) );
-  if( pH->htsize>0 ) sqlite3EndBenignMalloc();
+  sqlite3BeginBenignMalloc();
+  new_ht = (struct _ht *)sqlite3Malloc( new_size*sizeof(struct _ht) );
+  sqlite3EndBenignMalloc();
 
-  if( new_ht==0 ) return;
+  if( new_ht==0 ) return 0;
   sqlite3_free(pH->ht);
   pH->ht = new_ht;
-  pH->htsize = new_size;
+  pH->htsize = new_size = sqlite3MallocSize(new_ht)/sizeof(struct _ht);
+  memset(new_ht, 0, new_size*sizeof(struct _ht));
   for(elem=pH->first, pH->first=0; elem; elem = next_elem){
-    int h = strHash(elem->pKey, elem->nKey) & (new_size-1);
+    unsigned int h = strHash(elem->pKey, elem->nKey) % new_size;
     next_elem = elem->next;
     insertElement(pH, &new_ht[h], elem);
   }
+  return 1;
 }
 
 /* This function (for internal use only) locates an element in an
@@ -19865,9 +22254,9 @@ static void rehash(Hash *pH, int new_size){
 */
 static HashElem *findElementGivenHash(
   const Hash *pH,     /* The pH to be searched */
-  const void *pKey,   /* The key we are searching for */
-  int nKey,
-  int h               /* The hash for this key. */
+  const char *pKey,   /* The key we are searching for */
+  int nKey,           /* Bytes in key (not counting zero terminator) */
+  unsigned int h      /* The hash for this key. */
 ){
   HashElem *elem;                /* Used to loop thru the element list */
   int count;                     /* Number of elements left to test */
@@ -19876,12 +22265,15 @@ static HashElem *findElementGivenHash(
     struct _ht *pEntry = &pH->ht[h];
     elem = pEntry->chain;
     count = pEntry->count;
-    while( count-- && elem ){
-      if( strCompare(elem->pKey,elem->nKey,pKey,nKey)==0 ){ 
-        return elem;
-      }
-      elem = elem->next;
+  }else{
+    elem = pH->first;
+    count = pH->count;
+  }
+  while( count-- && ALWAYS(elem) ){
+    if( elem->nKey==nKey && sqlite3StrNICmp(elem->pKey,pKey,nKey)==0 ){ 
+      return elem;
     }
+    elem = elem->next;
   }
   return 0;
 }
@@ -19892,7 +22284,7 @@ static HashElem *findElementGivenHash(
 static void removeElementGivenHash(
   Hash *pH,         /* The pH containing "elem" */
   HashElem* elem,   /* The element to be removed from the pH */
-  int h             /* Hash value for the element */
+  unsigned int h    /* Hash value for the element */
 ){
   struct _ht *pEntry;
   if( elem->prev ){
@@ -19903,16 +22295,13 @@ static void removeElementGivenHash(
   if( elem->next ){
     elem->next->prev = elem->prev;
   }
-  pEntry = &pH->ht[h];
-  if( pEntry->chain==elem ){
-    pEntry->chain = elem->next;
-  }
-  pEntry->count--;
-  if( pEntry->count<=0 ){
-    pEntry->chain = 0;
-  }
-  if( pH->copyKey ){
-    sqlite3_free(elem->pKey);
+  if( pH->ht ){
+    pEntry = &pH->ht[h];
+    if( pEntry->chain==elem ){
+      pEntry->chain = elem->next;
+    }
+    pEntry->count--;
+    assert( pEntry->count>=0 );
   }
   sqlite3_free( elem );
   pH->count--;
@@ -19923,28 +22312,23 @@ static void removeElementGivenHash(
   }
 }
 
-/* Attempt to locate an element of the hash table pH with a key
-** that matches pKey,nKey.  Return a pointer to the corresponding 
-** HashElem structure for this element if it is found, or NULL
-** otherwise.
-*/
-SQLITE_PRIVATE HashElem *sqlite3HashFindElem(const Hash *pH, const void *pKey, int nKey){
-  int h;             /* A hash on key */
-  HashElem *elem;    /* The element that matches key */
-
-  if( pH==0 || pH->ht==0 ) return 0;
-  h = strHash(pKey,nKey);
-  elem = findElementGivenHash(pH,pKey,nKey, h % pH->htsize);
-  return elem;
-}
-
 /* Attempt to locate an element of the hash table pH with a key
 ** that matches pKey,nKey.  Return the data for this element if it is
 ** found, or NULL if there is no match.
 */
-SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const void *pKey, int nKey){
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const char *pKey, int nKey){
   HashElem *elem;    /* The element that matches key */
-  elem = sqlite3HashFindElem(pH, pKey, nKey);
+  unsigned int h;    /* A hash on key */
+
+  assert( pH!=0 );
+  assert( pKey!=0 );
+  assert( nKey>=0 );
+  if( pH->ht ){
+    h = strHash(pKey, nKey) % pH->htsize;
+  }else{
+    h = 0;
+  }
+  elem = findElementGivenHash(pH, pKey, nKey, h);
   return elem ? elem->data : 0;
 }
 
@@ -19952,8 +22336,7 @@ SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const void *pKey, int nKey)
 ** and the data is "data".
 **
 ** If no element exists with a matching key, then a new
-** element is created.  A copy of the key is made if the copyKey
-** flag is set.  NULL is returned.
+** element is created and NULL is returned.
 **
 ** If another element already exists with the same key, then the
 ** new data replaces the old data and the old data is returned.
@@ -19963,64 +22346,49 @@ SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const void *pKey, int nKey)
 ** If the "data" parameter to this function is NULL, then the
 ** element corresponding to "key" is removed from the hash table.
 */
-SQLITE_PRIVATE void *sqlite3HashInsert(Hash *pH, const void *pKey, int nKey, void *data){
-  int hraw;             /* Raw hash value of the key */
-  int h;                /* the hash of the key modulo hash table size */
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash *pH, const char *pKey, int nKey, void *data){
+  unsigned int h;       /* the hash of the key modulo hash table size */
   HashElem *elem;       /* Used to loop thru the element list */
   HashElem *new_elem;   /* New element added to the pH */
 
   assert( pH!=0 );
-  hraw = strHash(pKey, nKey);
+  assert( pKey!=0 );
+  assert( nKey>=0 );
   if( pH->htsize ){
-    h = hraw % pH->htsize;
-    elem = findElementGivenHash(pH,pKey,nKey,h);
-    if( elem ){
-      void *old_data = elem->data;
-      if( data==0 ){
-        removeElementGivenHash(pH,elem,h);
-      }else{
-        elem->data = data;
-        if( !pH->copyKey ){
-          elem->pKey = (void *)pKey;
-        }
-        assert(nKey==elem->nKey);
-      }
-      return old_data;
+    h = strHash(pKey, nKey) % pH->htsize;
+  }else{
+    h = 0;
+  }
+  elem = findElementGivenHash(pH,pKey,nKey,h);
+  if( elem ){
+    void *old_data = elem->data;
+    if( data==0 ){
+      removeElementGivenHash(pH,elem,h);
+    }else{
+      elem->data = data;
+      elem->pKey = pKey;
+      assert(nKey==elem->nKey);
     }
+    return old_data;
   }
   if( data==0 ) return 0;
   new_elem = (HashElem*)sqlite3Malloc( sizeof(HashElem) );
   if( new_elem==0 ) return data;
-  if( pH->copyKey && pKey!=0 ){
-    new_elem->pKey = sqlite3Malloc( nKey );
-    if( new_elem->pKey==0 ){
-      sqlite3_free(new_elem);
-      return data;
-    }
-    memcpy((void*)new_elem->pKey, pKey, nKey);
-  }else{
-    new_elem->pKey = (void*)pKey;
-  }
+  new_elem->pKey = pKey;
   new_elem->nKey = nKey;
+  new_elem->data = data;
   pH->count++;
-  if( pH->htsize==0 ){
-    rehash(pH, 128/sizeof(pH->ht[0]));
-    if( pH->htsize==0 ){
-      pH->count = 0;
-      if( pH->copyKey ){
-        sqlite3_free(new_elem->pKey);
-      }
-      sqlite3_free(new_elem);
-      return data;
+  if( pH->count>=10 && pH->count > 2*pH->htsize ){
+    if( rehash(pH, pH->count*2) ){
+      assert( pH->htsize>0 );
+      h = strHash(pKey, nKey) % pH->htsize;
     }
   }
-  if( pH->count > pH->htsize ){
-    rehash(pH,pH->htsize*2);
+  if( pH->ht ){
+    insertElement(pH, &pH->ht[h], new_elem);
+  }else{
+    insertElement(pH, 0, new_elem);
   }
-  assert( pH->htsize>0 );
-  h = hraw % pH->htsize;
-  insertElement(pH, &pH->ht[h], new_elem);
-  new_elem->data = data;
   return 0;
 }
 
@@ -20031,1518 +22399,162 @@ SQLITE_PRIVATE void *sqlite3HashInsert(Hash *pH, const void *pKey, int nKey, voi
 #if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
 SQLITE_PRIVATE const char *sqlite3OpcodeName(int i){
  static const char *const azName[] = { "?",
-     /*   1 */ "VNext",
-     /*   2 */ "Affinity",
-     /*   3 */ "Column",
-     /*   4 */ "SetCookie",
-     /*   5 */ "Seek",
-     /*   6 */ "Sequence",
-     /*   7 */ "Savepoint",
-     /*   8 */ "RowKey",
-     /*   9 */ "SCopy",
-     /*  10 */ "OpenWrite",
-     /*  11 */ "If",
-     /*  12 */ "VRowid",
-     /*  13 */ "CollSeq",
-     /*  14 */ "OpenRead",
-     /*  15 */ "Expire",
-     /*  16 */ "AutoCommit",
-     /*  17 */ "Pagecount",
-     /*  18 */ "IntegrityCk",
+     /*   1 */ "Goto",
+     /*   2 */ "Gosub",
+     /*   3 */ "Return",
+     /*   4 */ "Yield",
+     /*   5 */ "HaltIfNull",
+     /*   6 */ "Halt",
+     /*   7 */ "Integer",
+     /*   8 */ "Int64",
+     /*   9 */ "String",
+     /*  10 */ "Null",
+     /*  11 */ "Blob",
+     /*  12 */ "Variable",
+     /*  13 */ "Move",
+     /*  14 */ "Copy",
+     /*  15 */ "SCopy",
+     /*  16 */ "ResultRow",
+     /*  17 */ "CollSeq",
+     /*  18 */ "Function",
      /*  19 */ "Not",
-     /*  20 */ "Sort",
-     /*  21 */ "Copy",
-     /*  22 */ "Trace",
-     /*  23 */ "Function",
-     /*  24 */ "IfNeg",
-     /*  25 */ "Noop",
-     /*  26 */ "Return",
-     /*  27 */ "NewRowid",
-     /*  28 */ "Variable",
-     /*  29 */ "String",
-     /*  30 */ "RealAffinity",
-     /*  31 */ "VRename",
-     /*  32 */ "ParseSchema",
-     /*  33 */ "VOpen",
-     /*  34 */ "Close",
-     /*  35 */ "CreateIndex",
-     /*  36 */ "IsUnique",
-     /*  37 */ "NotFound",
-     /*  38 */ "Int64",
-     /*  39 */ "MustBeInt",
-     /*  40 */ "Halt",
-     /*  41 */ "Rowid",
-     /*  42 */ "IdxLT",
-     /*  43 */ "AddImm",
-     /*  44 */ "Statement",
-     /*  45 */ "RowData",
-     /*  46 */ "MemMax",
-     /*  47 */ "NotExists",
-     /*  48 */ "Gosub",
-     /*  49 */ "Integer",
-     /*  50 */ "Prev",
-     /*  51 */ "RowSetRead",
-     /*  52 */ "RowSetAdd",
-     /*  53 */ "VColumn",
-     /*  54 */ "CreateTable",
-     /*  55 */ "Last",
-     /*  56 */ "SeekLe",
-     /*  57 */ "IncrVacuum",
-     /*  58 */ "IdxRowid",
-     /*  59 */ "ResetCount",
-     /*  60 */ "ContextPush",
-     /*  61 */ "Yield",
-     /*  62 */ "DropTrigger",
-     /*  63 */ "Or",
-     /*  64 */ "And",
-     /*  65 */ "DropIndex",
-     /*  66 */ "IdxGE",
-     /*  67 */ "IdxDelete",
-     /*  68 */ "IsNull",
-     /*  69 */ "NotNull",
-     /*  70 */ "Ne",
-     /*  71 */ "Eq",
-     /*  72 */ "Gt",
-     /*  73 */ "Le",
-     /*  74 */ "Lt",
-     /*  75 */ "Ge",
-     /*  76 */ "Vacuum",
-     /*  77 */ "BitAnd",
-     /*  78 */ "BitOr",
-     /*  79 */ "ShiftLeft",
-     /*  80 */ "ShiftRight",
-     /*  81 */ "Add",
-     /*  82 */ "Subtract",
-     /*  83 */ "Multiply",
-     /*  84 */ "Divide",
-     /*  85 */ "Remainder",
-     /*  86 */ "Concat",
-     /*  87 */ "IfNot",
-     /*  88 */ "DropTable",
-     /*  89 */ "SeekLt",
-     /*  90 */ "BitNot",
-     /*  91 */ "String8",
-     /*  92 */ "MakeRecord",
-     /*  93 */ "ResultRow",
-     /*  94 */ "Delete",
-     /*  95 */ "AggFinal",
-     /*  96 */ "Compare",
-     /*  97 */ "Goto",
-     /*  98 */ "TableLock",
-     /*  99 */ "Clear",
-     /* 100 */ "VerifyCookie",
-     /* 101 */ "AggStep",
-     /* 102 */ "SetNumColumns",
-     /* 103 */ "Transaction",
-     /* 104 */ "VFilter",
-     /* 105 */ "VDestroy",
-     /* 106 */ "ContextPop",
-     /* 107 */ "Next",
-     /* 108 */ "IdxInsert",
-     /* 109 */ "SeekGe",
-     /* 110 */ "Insert",
-     /* 111 */ "Destroy",
-     /* 112 */ "ReadCookie",
-     /* 113 */ "LoadAnalysis",
-     /* 114 */ "Explain",
-     /* 115 */ "OpenPseudo",
-     /* 116 */ "OpenEphemeral",
-     /* 117 */ "Null",
-     /* 118 */ "Move",
-     /* 119 */ "Blob",
-     /* 120 */ "Rewind",
-     /* 121 */ "SeekGt",
-     /* 122 */ "VBegin",
-     /* 123 */ "VUpdate",
-     /* 124 */ "IfZero",
-     /* 125 */ "VCreate",
-     /* 126 */ "Found",
-     /* 127 */ "IfPos",
-     /* 128 */ "NullRow",
-     /* 129 */ "Real",
-     /* 130 */ "Jump",
-     /* 131 */ "Permutation",
-     /* 132 */ "NotUsed_132",
-     /* 133 */ "NotUsed_133",
-     /* 134 */ "NotUsed_134",
-     /* 135 */ "NotUsed_135",
-     /* 136 */ "NotUsed_136",
-     /* 137 */ "NotUsed_137",
-     /* 138 */ "NotUsed_138",
-     /* 139 */ "NotUsed_139",
-     /* 140 */ "NotUsed_140",
+     /*  20 */ "AddImm",
+     /*  21 */ "MustBeInt",
+     /*  22 */ "RealAffinity",
+     /*  23 */ "Permutation",
+     /*  24 */ "Compare",
+     /*  25 */ "Jump",
+     /*  26 */ "Once",
+     /*  27 */ "If",
+     /*  28 */ "IfNot",
+     /*  29 */ "Column",
+     /*  30 */ "Affinity",
+     /*  31 */ "MakeRecord",
+     /*  32 */ "Count",
+     /*  33 */ "Savepoint",
+     /*  34 */ "AutoCommit",
+     /*  35 */ "Transaction",
+     /*  36 */ "ReadCookie",
+     /*  37 */ "SetCookie",
+     /*  38 */ "VerifyCookie",
+     /*  39 */ "OpenRead",
+     /*  40 */ "OpenWrite",
+     /*  41 */ "OpenAutoindex",
+     /*  42 */ "OpenEphemeral",
+     /*  43 */ "SorterOpen",
+     /*  44 */ "OpenPseudo",
+     /*  45 */ "Close",
+     /*  46 */ "SeekLt",
+     /*  47 */ "SeekLe",
+     /*  48 */ "SeekGe",
+     /*  49 */ "SeekGt",
+     /*  50 */ "Seek",
+     /*  51 */ "NotFound",
+     /*  52 */ "Found",
+     /*  53 */ "IsUnique",
+     /*  54 */ "NotExists",
+     /*  55 */ "Sequence",
+     /*  56 */ "NewRowid",
+     /*  57 */ "Insert",
+     /*  58 */ "InsertInt",
+     /*  59 */ "Delete",
+     /*  60 */ "ResetCount",
+     /*  61 */ "SorterCompare",
+     /*  62 */ "SorterData",
+     /*  63 */ "RowKey",
+     /*  64 */ "RowData",
+     /*  65 */ "Rowid",
+     /*  66 */ "NullRow",
+     /*  67 */ "Last",
+     /*  68 */ "Or",
+     /*  69 */ "And",
+     /*  70 */ "SorterSort",
+     /*  71 */ "Sort",
+     /*  72 */ "Rewind",
+     /*  73 */ "IsNull",
+     /*  74 */ "NotNull",
+     /*  75 */ "Ne",
+     /*  76 */ "Eq",
+     /*  77 */ "Gt",
+     /*  78 */ "Le",
+     /*  79 */ "Lt",
+     /*  80 */ "Ge",
+     /*  81 */ "SorterNext",
+     /*  82 */ "BitAnd",
+     /*  83 */ "BitOr",
+     /*  84 */ "ShiftLeft",
+     /*  85 */ "ShiftRight",
+     /*  86 */ "Add",
+     /*  87 */ "Subtract",
+     /*  88 */ "Multiply",
+     /*  89 */ "Divide",
+     /*  90 */ "Remainder",
+     /*  91 */ "Concat",
+     /*  92 */ "Prev",
+     /*  93 */ "BitNot",
+     /*  94 */ "String8",
+     /*  95 */ "Next",
+     /*  96 */ "SorterInsert",
+     /*  97 */ "IdxInsert",
+     /*  98 */ "IdxDelete",
+     /*  99 */ "IdxRowid",
+     /* 100 */ "IdxLT",
+     /* 101 */ "IdxGE",
+     /* 102 */ "Destroy",
+     /* 103 */ "Clear",
+     /* 104 */ "CreateIndex",
+     /* 105 */ "CreateTable",
+     /* 106 */ "ParseSchema",
+     /* 107 */ "LoadAnalysis",
+     /* 108 */ "DropTable",
+     /* 109 */ "DropIndex",
+     /* 110 */ "DropTrigger",
+     /* 111 */ "IntegrityCk",
+     /* 112 */ "RowSetAdd",
+     /* 113 */ "RowSetRead",
+     /* 114 */ "RowSetTest",
+     /* 115 */ "Program",
+     /* 116 */ "Param",
+     /* 117 */ "FkCounter",
+     /* 118 */ "FkIfZero",
+     /* 119 */ "MemMax",
+     /* 120 */ "IfPos",
+     /* 121 */ "IfNeg",
+     /* 122 */ "IfZero",
+     /* 123 */ "AggStep",
+     /* 124 */ "AggFinal",
+     /* 125 */ "Checkpoint",
+     /* 126 */ "JournalMode",
+     /* 127 */ "Vacuum",
+     /* 128 */ "IncrVacuum",
+     /* 129 */ "Expire",
+     /* 130 */ "Real",
+     /* 131 */ "TableLock",
+     /* 132 */ "VBegin",
+     /* 133 */ "VCreate",
+     /* 134 */ "VDestroy",
+     /* 135 */ "VOpen",
+     /* 136 */ "VFilter",
+     /* 137 */ "VColumn",
+     /* 138 */ "VNext",
+     /* 139 */ "VRename",
+     /* 140 */ "VUpdate",
      /* 141 */ "ToText",
      /* 142 */ "ToBlob",
      /* 143 */ "ToNumeric",
      /* 144 */ "ToInt",
      /* 145 */ "ToReal",
+     /* 146 */ "Pagecount",
+     /* 147 */ "MaxPgcnt",
+     /* 148 */ "Trace",
+     /* 149 */ "Noop",
+     /* 150 */ "Explain",
   };
   return azName[i];
 }
 #endif
 
 /************** End of opcodes.c *********************************************/
-/************** Begin file os_os2.c ******************************************/
-/*
-** 2006 Feb 14
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-******************************************************************************
-**
-** This file contains code that is specific to OS/2.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-*/
-
-
-#if SQLITE_OS_OS2
-
-/*
-** A Note About Memory Allocation:
-**
-** This driver uses malloc()/free() directly rather than going through
-** the SQLite-wrappers sqlite3_malloc()/sqlite3_free().  Those wrappers
-** are designed for use on embedded systems where memory is scarce and
-** malloc failures happen frequently.  OS/2 does not typically run on
-** embedded systems, and when it does the developers normally have bigger
-** problems to worry about than running out of memory.  So there is not
-** a compelling need to use the wrappers.
-**
-** But there is a good reason to not use the wrappers.  If we use the
-** wrappers then we will get simulated malloc() failures within this
-** driver.  And that causes all kinds of problems for our tests.  We
-** could enhance SQLite to deal with simulated malloc failures within
-** the OS driver, but the code to deal with those failure would not
-** be exercised on Linux (which does not need to malloc() in the driver)
-** and so we would have difficulty writing coverage tests for that
-** code.  Better to leave the code out, we think.
-**
-** The point of this discussion is as follows:  When creating a new
-** OS layer for an embedded system, if you use this file as an example,
-** avoid the use of malloc()/free().  Those routines work ok on OS/2
-** desktops but not so well in embedded systems.
-*/
-
-/*
-** Macros used to determine whether or not to use threads.
-*/
-#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE
-# define SQLITE_OS2_THREADS 1
-#endif
-
-/*
-** Include code that is common to all os_*.c files
-*/
-/************** Include os_common.h in the middle of os_os2.c ****************/
-/************** Begin file os_common.h ***************************************/
-/*
-** 2004 May 22
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-******************************************************************************
-**
-** This file contains macros and a little bit of code that is common to
-** all of the platform-specific files (os_*.c) and is #included into those
-** files.
-**
-** This file should be #included by the os_*.c files only.  It is not a
-** general purpose header file.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-*/
-#ifndef _OS_COMMON_H_
-#define _OS_COMMON_H_
-
-/*
-** At least two bugs have slipped in because we changed the MEMORY_DEBUG
-** macro to SQLITE_DEBUG and some older makefiles have not yet made the
-** switch.  The following code should catch this problem at compile-time.
-*/
-#ifdef MEMORY_DEBUG
-# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
-#endif
-
-
-/*
- * When testing, this global variable stores the location of the
- * pending-byte in the database file.
- */
-#ifdef SQLITE_TEST
-SQLITE_API unsigned int sqlite3_pending_byte = 0x40000000;
-#endif
-
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE int sqlite3OSTrace = 0;
-#define OSTRACE1(X)         if( sqlite3OSTrace ) sqlite3DebugPrintf(X)
-#define OSTRACE2(X,Y)       if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y)
-#define OSTRACE3(X,Y,Z)     if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z)
-#define OSTRACE4(X,Y,Z,A)   if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A)
-#define OSTRACE5(X,Y,Z,A,B) if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A,B)
-#define OSTRACE6(X,Y,Z,A,B,C) \
-    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
-#define OSTRACE7(X,Y,Z,A,B,C,D) \
-    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
-#else
-#define OSTRACE1(X)
-#define OSTRACE2(X,Y)
-#define OSTRACE3(X,Y,Z)
-#define OSTRACE4(X,Y,Z,A)
-#define OSTRACE5(X,Y,Z,A,B)
-#define OSTRACE6(X,Y,Z,A,B,C)
-#define OSTRACE7(X,Y,Z,A,B,C,D)
-#endif
-
-/*
-** Macros for performance tracing.  Normally turned off.  Only works
-** on i486 hardware.
-*/
-#ifdef SQLITE_PERFORMANCE_TRACE
-
-/* 
-** hwtime.h contains inline assembler code for implementing 
-** high-performance timing routines.
-*/
-/************** Include hwtime.h in the middle of os_common.h ****************/
-/************** Begin file hwtime.h ******************************************/
-/*
-** 2008 May 27
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-******************************************************************************
-**
-** This file contains inline asm code for retrieving "high-performance"
-** counters for x86 class CPUs.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-*/
-#ifndef _HWTIME_H_
-#define _HWTIME_H_
-
-/*
-** The following routine only works on pentium-class (or newer) processors.
-** It uses the RDTSC opcode to read the cycle count value out of the
-** processor and returns that value.  This can be used for high-res
-** profiling.
-*/
-#if (defined(__GNUC__) || defined(_MSC_VER)) && \
-      (defined(i386) || defined(__i386__) || defined(_M_IX86))
-
-  #if defined(__GNUC__)
-
-  __inline__ sqlite_uint64 sqlite3Hwtime(void){
-     unsigned int lo, hi;
-     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
-     return (sqlite_uint64)hi << 32 | lo;
-  }
-
-  #elif defined(_MSC_VER)
-
-  __declspec(naked) __inline sqlite_uint64 __cdecl sqlite3Hwtime(void){
-     __asm {
-        rdtsc
-        ret       ; return value at EDX:EAX
-     }
-  }
-
-  #endif
-
-#elif (defined(__GNUC__) && defined(__x86_64__))
-
-  __inline__ sqlite_uint64 sqlite3Hwtime(void){
-      unsigned long val;
-      __asm__ __volatile__ ("rdtsc" : "=A" (val));
-      return val;
-  }
- 
-#elif (defined(__GNUC__) && defined(__ppc__))
-
-  __inline__ sqlite_uint64 sqlite3Hwtime(void){
-      unsigned long long retval;
-      unsigned long junk;
-      __asm__ __volatile__ ("\n\
-          1:      mftbu   %1\n\
-                  mftb    %L0\n\
-                  mftbu   %0\n\
-                  cmpw    %0,%1\n\
-                  bne     1b"
-                  : "=r" (retval), "=r" (junk));
-      return retval;
-  }
-
-#else
-
-  #error Need implementation of sqlite3Hwtime() for your platform.
-
-  /*
-  ** To compile without implementing sqlite3Hwtime() for your platform,
-  ** you can remove the above #error and use the following
-  ** stub function.  You will lose timing support for many
-  ** of the debugging and testing utilities, but it should at
-  ** least compile and run.
-  */
-SQLITE_PRIVATE   sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }
-
-#endif
-
-#endif /* !defined(_HWTIME_H_) */
-
-/************** End of hwtime.h **********************************************/
-/************** Continuing where we left off in os_common.h ******************/
-
-static sqlite_uint64 g_start;
-static sqlite_uint64 g_elapsed;
-#define TIMER_START       g_start=sqlite3Hwtime()
-#define TIMER_END         g_elapsed=sqlite3Hwtime()-g_start
-#define TIMER_ELAPSED     g_elapsed
-#else
-#define TIMER_START
-#define TIMER_END
-#define TIMER_ELAPSED     ((sqlite_uint64)0)
-#endif
-
-/*
-** If we compile with the SQLITE_TEST macro set, then the following block
-** of code will give us the ability to simulate a disk I/O error.  This
-** is used for testing the I/O recovery logic.
-*/
-#ifdef SQLITE_TEST
-SQLITE_API int sqlite3_io_error_hit = 0;            /* Total number of I/O Errors */
-SQLITE_API int sqlite3_io_error_hardhit = 0;        /* Number of non-benign errors */
-SQLITE_API int sqlite3_io_error_pending = 0;        /* Count down to first I/O error */
-SQLITE_API int sqlite3_io_error_persist = 0;        /* True if I/O errors persist */
-SQLITE_API int sqlite3_io_error_benign = 0;         /* True if errors are benign */
-SQLITE_API int sqlite3_diskfull_pending = 0;
-SQLITE_API int sqlite3_diskfull = 0;
-#define SimulateIOErrorBenign(X) sqlite3_io_error_benign=(X)
-#define SimulateIOError(CODE)  \
-  if( (sqlite3_io_error_persist && sqlite3_io_error_hit) \
-       || sqlite3_io_error_pending-- == 1 )  \
-              { local_ioerr(); CODE; }
-static void local_ioerr(){
-  IOTRACE(("IOERR\n"));
-  sqlite3_io_error_hit++;
-  if( !sqlite3_io_error_benign ) sqlite3_io_error_hardhit++;
-}
-#define SimulateDiskfullError(CODE) \
-   if( sqlite3_diskfull_pending ){ \
-     if( sqlite3_diskfull_pending == 1 ){ \
-       local_ioerr(); \
-       sqlite3_diskfull = 1; \
-       sqlite3_io_error_hit = 1; \
-       CODE; \
-     }else{ \
-       sqlite3_diskfull_pending--; \
-     } \
-   }
-#else
-#define SimulateIOErrorBenign(X)
-#define SimulateIOError(A)
-#define SimulateDiskfullError(A)
-#endif
-
-/*
-** When testing, keep a count of the number of open files.
-*/
-#ifdef SQLITE_TEST
-SQLITE_API int sqlite3_open_file_count = 0;
-#define OpenCounter(X)  sqlite3_open_file_count+=(X)
-#else
-#define OpenCounter(X)
-#endif
-
-#endif /* !defined(_OS_COMMON_H_) */
-
-/************** End of os_common.h *******************************************/
-/************** Continuing where we left off in os_os2.c *********************/
-
-/*
-** The os2File structure is subclass of sqlite3_file specific for the OS/2
-** protability layer.
-*/
-typedef struct os2File os2File;
-struct os2File {
-  const sqlite3_io_methods *pMethod;  /* Always the first entry */
-  HFILE h;                  /* Handle for accessing the file */
-  char* pathToDel;          /* Name of file to delete on close, NULL if not */
-  unsigned char locktype;   /* Type of lock currently held on this file */
-};
-
-#define LOCK_TIMEOUT 10L /* the default locking timeout */
-
-/*****************************************************************************
-** The next group of routines implement the I/O methods specified
-** by the sqlite3_io_methods object.
-******************************************************************************/
-
-/*
-** Close a file.
-*/
-static int os2Close( sqlite3_file *id ){
-  APIRET rc = NO_ERROR;
-  os2File *pFile;
-  if( id && (pFile = (os2File*)id) != 0 ){
-    OSTRACE2( "CLOSE %d\n", pFile->h );
-    rc = DosClose( pFile->h );
-    pFile->locktype = NO_LOCK;
-    if( pFile->pathToDel != NULL ){
-      rc = DosForceDelete( (PSZ)pFile->pathToDel );
-      free( pFile->pathToDel );
-      pFile->pathToDel = NULL;
-    }
-    id = 0;
-    OpenCounter( -1 );
-  }
-
-  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
-}
-
-/*
-** Read data from a file into a buffer.  Return SQLITE_OK if all
-** bytes were read successfully and SQLITE_IOERR if anything goes
-** wrong.
-*/
-static int os2Read(
-  sqlite3_file *id,               /* File to read from */
-  void *pBuf,                     /* Write content into this buffer */
-  int amt,                        /* Number of bytes to read */
-  sqlite3_int64 offset            /* Begin reading at this offset */
-){
-  ULONG fileLocation = 0L;
-  ULONG got;
-  os2File *pFile = (os2File*)id;
-  assert( id!=0 );
-  SimulateIOError( return SQLITE_IOERR_READ );
-  OSTRACE3( "READ %d lock=%d\n", pFile->h, pFile->locktype );
-  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
-    return SQLITE_IOERR;
-  }
-  if( DosRead( pFile->h, pBuf, amt, &got ) != NO_ERROR ){
-    return SQLITE_IOERR_READ;
-  }
-  if( got == (ULONG)amt )
-    return SQLITE_OK;
-  else {
-    /* Unread portions of the input buffer must be zero-filled */
-    memset(&((char*)pBuf)[got], 0, amt-got);
-    return SQLITE_IOERR_SHORT_READ;
-  }
-}
-
-/*
-** Write data from a buffer into a file.  Return SQLITE_OK on success
-** or some other error code on failure.
-*/
-static int os2Write(
-  sqlite3_file *id,               /* File to write into */
-  const void *pBuf,               /* The bytes to be written */
-  int amt,                        /* Number of bytes to write */
-  sqlite3_int64 offset            /* Offset into the file to begin writing at */
-){
-  ULONG fileLocation = 0L;
-  APIRET rc = NO_ERROR;
-  ULONG wrote;
-  os2File *pFile = (os2File*)id;
-  assert( id!=0 );
-  SimulateIOError( return SQLITE_IOERR_WRITE );
-  SimulateDiskfullError( return SQLITE_FULL );
-  OSTRACE3( "WRITE %d lock=%d\n", pFile->h, pFile->locktype );
-  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
-    return SQLITE_IOERR;
-  }
-  assert( amt>0 );
-  while( amt > 0 &&
-         ( rc = DosWrite( pFile->h, (PVOID)pBuf, amt, &wrote ) ) == NO_ERROR &&
-         wrote > 0
-  ){
-    amt -= wrote;
-    pBuf = &((char*)pBuf)[wrote];
-  }
-
-  return ( rc != NO_ERROR || amt > (int)wrote ) ? SQLITE_FULL : SQLITE_OK;
-}
-
-/*
-** Truncate an open file to a specified size
-*/
-static int os2Truncate( sqlite3_file *id, i64 nByte ){
-  APIRET rc = NO_ERROR;
-  os2File *pFile = (os2File*)id;
-  OSTRACE3( "TRUNCATE %d %lld\n", pFile->h, nByte );
-  SimulateIOError( return SQLITE_IOERR_TRUNCATE );
-  rc = DosSetFileSize( pFile->h, nByte );
-  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR_TRUNCATE;
-}
-
-#ifdef SQLITE_TEST
-/*
-** Count the number of fullsyncs and normal syncs.  This is used to test
-** that syncs and fullsyncs are occuring at the right times.
-*/
-SQLITE_API int sqlite3_sync_count = 0;
-SQLITE_API int sqlite3_fullsync_count = 0;
-#endif
-
-/*
-** Make sure all writes to a particular file are committed to disk.
-*/
-static int os2Sync( sqlite3_file *id, int flags ){
-  os2File *pFile = (os2File*)id;
-  OSTRACE3( "SYNC %d lock=%d\n", pFile->h, pFile->locktype );
-#ifdef SQLITE_TEST
-  if( flags & SQLITE_SYNC_FULL){
-    sqlite3_fullsync_count++;
-  }
-  sqlite3_sync_count++;
-#endif
-  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
-  ** no-op
-  */
-#ifdef SQLITE_NO_SYNC
-  UNUSED_PARAMETER(pFile);
-  return SQLITE_OK;
-#else
-  return DosResetBuffer( pFile->h ) == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
-#endif
-}
-
-/*
-** Determine the current size of a file in bytes
-*/
-static int os2FileSize( sqlite3_file *id, sqlite3_int64 *pSize ){
-  APIRET rc = NO_ERROR;
-  FILESTATUS3 fsts3FileInfo;
-  memset(&fsts3FileInfo, 0, sizeof(fsts3FileInfo));
-  assert( id!=0 );
-  SimulateIOError( return SQLITE_IOERR_FSTAT );
-  rc = DosQueryFileInfo( ((os2File*)id)->h, FIL_STANDARD, &fsts3FileInfo, sizeof(FILESTATUS3) );
-  if( rc == NO_ERROR ){
-    *pSize = fsts3FileInfo.cbFile;
-    return SQLITE_OK;
-  }else{
-    return SQLITE_IOERR_FSTAT;
-  }
-}
-
-/*
-** Acquire a reader lock.
-*/
-static int getReadLock( os2File *pFile ){
-  FILELOCK  LockArea,
-            UnlockArea;
-  APIRET res;
-  memset(&LockArea, 0, sizeof(LockArea));
-  memset(&UnlockArea, 0, sizeof(UnlockArea));
-  LockArea.lOffset = SHARED_FIRST;
-  LockArea.lRange = SHARED_SIZE;
-  UnlockArea.lOffset = 0L;
-  UnlockArea.lRange = 0L;
-  res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
-  OSTRACE3( "GETREADLOCK %d res=%d\n", pFile->h, res );
-  return res;
-}
-
-/*
-** Undo a readlock
-*/
-static int unlockReadLock( os2File *id ){
-  FILELOCK  LockArea,
-            UnlockArea;
-  APIRET res;
-  memset(&LockArea, 0, sizeof(LockArea));
-  memset(&UnlockArea, 0, sizeof(UnlockArea));
-  LockArea.lOffset = 0L;
-  LockArea.lRange = 0L;
-  UnlockArea.lOffset = SHARED_FIRST;
-  UnlockArea.lRange = SHARED_SIZE;
-  res = DosSetFileLocks( id->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
-  OSTRACE3( "UNLOCK-READLOCK file handle=%d res=%d?\n", id->h, res );
-  return res;
-}
-
-/*
-** Lock the file with the lock specified by parameter locktype - one
-** of the following:
-**
-**     (1) SHARED_LOCK
-**     (2) RESERVED_LOCK
-**     (3) PENDING_LOCK
-**     (4) EXCLUSIVE_LOCK
-**
-** Sometimes when requesting one lock state, additional lock states
-** are inserted in between.  The locking might fail on one of the later
-** transitions leaving the lock state different from what it started but
-** still short of its goal.  The following chart shows the allowed
-** transitions and the inserted intermediate states:
-**
-**    UNLOCKED -> SHARED
-**    SHARED -> RESERVED
-**    SHARED -> (PENDING) -> EXCLUSIVE
-**    RESERVED -> (PENDING) -> EXCLUSIVE
-**    PENDING -> EXCLUSIVE
-**
-** This routine will only increase a lock.  The os2Unlock() routine
-** erases all locks at once and returns us immediately to locking level 0.
-** It is not possible to lower the locking level one step at a time.  You
-** must go straight to locking level 0.
-*/
-static int os2Lock( sqlite3_file *id, int locktype ){
-  int rc = SQLITE_OK;       /* Return code from subroutines */
-  APIRET res = NO_ERROR;    /* Result of an OS/2 lock call */
-  int newLocktype;       /* Set pFile->locktype to this value before exiting */
-  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
-  FILELOCK  LockArea,
-            UnlockArea;
-  os2File *pFile = (os2File*)id;
-  memset(&LockArea, 0, sizeof(LockArea));
-  memset(&UnlockArea, 0, sizeof(UnlockArea));
-  assert( pFile!=0 );
-  OSTRACE4( "LOCK %d %d was %d\n", pFile->h, locktype, pFile->locktype );
-
-  /* If there is already a lock of this type or more restrictive on the
-  ** os2File, do nothing. Don't use the end_lock: exit path, as
-  ** sqlite3_mutex_enter() hasn't been called yet.
-  */
-  if( pFile->locktype>=locktype ){
-    OSTRACE3( "LOCK %d %d ok (already held)\n", pFile->h, locktype );
-    return SQLITE_OK;
-  }
-
-  /* Make sure the locking sequence is correct
-  */
-  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
-  assert( locktype!=PENDING_LOCK );
-  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
-
-  /* Lock the PENDING_LOCK byte if we need to acquire a PENDING lock or
-  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
-  ** the PENDING_LOCK byte is temporary.
-  */
-  newLocktype = pFile->locktype;
-  if( pFile->locktype==NO_LOCK
-      || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
-  ){
-    LockArea.lOffset = PENDING_BYTE;
-    LockArea.lRange = 1L;
-    UnlockArea.lOffset = 0L;
-    UnlockArea.lRange = 0L;
-
-    /* wait longer than LOCK_TIMEOUT here not to have to try multiple times */
-    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 100L, 0L );
-    if( res == NO_ERROR ){
-      gotPendingLock = 1;
-      OSTRACE3( "LOCK %d pending lock boolean set.  res=%d\n", pFile->h, res );
-    }
-  }
-
-  /* Acquire a shared lock
-  */
-  if( locktype==SHARED_LOCK && res == NO_ERROR ){
-    assert( pFile->locktype==NO_LOCK );
-    res = getReadLock(pFile);
-    if( res == NO_ERROR ){
-      newLocktype = SHARED_LOCK;
-    }
-    OSTRACE3( "LOCK %d acquire shared lock. res=%d\n", pFile->h, res );
-  }
-
-  /* Acquire a RESERVED lock
-  */
-  if( locktype==RESERVED_LOCK && res == NO_ERROR ){
-    assert( pFile->locktype==SHARED_LOCK );
-    LockArea.lOffset = RESERVED_BYTE;
-    LockArea.lRange = 1L;
-    UnlockArea.lOffset = 0L;
-    UnlockArea.lRange = 0L;
-    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-    if( res == NO_ERROR ){
-      newLocktype = RESERVED_LOCK;
-    }
-    OSTRACE3( "LOCK %d acquire reserved lock. res=%d\n", pFile->h, res );
-  }
-
-  /* Acquire a PENDING lock
-  */
-  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
-    newLocktype = PENDING_LOCK;
-    gotPendingLock = 0;
-    OSTRACE2( "LOCK %d acquire pending lock. pending lock boolean unset.\n", pFile->h );
-  }
-
-  /* Acquire an EXCLUSIVE lock
-  */
-  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
-    assert( pFile->locktype>=SHARED_LOCK );
-    res = unlockReadLock(pFile);
-    OSTRACE2( "unreadlock = %d\n", res );
-    LockArea.lOffset = SHARED_FIRST;
-    LockArea.lRange = SHARED_SIZE;
-    UnlockArea.lOffset = 0L;
-    UnlockArea.lRange = 0L;
-    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-    if( res == NO_ERROR ){
-      newLocktype = EXCLUSIVE_LOCK;
-    }else{
-      OSTRACE2( "OS/2 error-code = %d\n", res );
-      getReadLock(pFile);
-    }
-    OSTRACE3( "LOCK %d acquire exclusive lock.  res=%d\n", pFile->h, res );
-  }
-
-  /* If we are holding a PENDING lock that ought to be released, then
-  ** release it now.
-  */
-  if( gotPendingLock && locktype==SHARED_LOCK ){
-    int r;
-    LockArea.lOffset = 0L;
-    LockArea.lRange = 0L;
-    UnlockArea.lOffset = PENDING_BYTE;
-    UnlockArea.lRange = 1L;
-    r = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-    OSTRACE3( "LOCK %d unlocking pending/is shared. r=%d\n", pFile->h, r );
-  }
-
-  /* Update the state of the lock has held in the file descriptor then
-  ** return the appropriate result code.
-  */
-  if( res == NO_ERROR ){
-    rc = SQLITE_OK;
-  }else{
-    OSTRACE4( "LOCK FAILED %d trying for %d but got %d\n", pFile->h,
-              locktype, newLocktype );
-    rc = SQLITE_BUSY;
-  }
-  pFile->locktype = newLocktype;
-  OSTRACE3( "LOCK %d now %d\n", pFile->h, pFile->locktype );
-  return rc;
-}
-
-/*
-** This routine checks if there is a RESERVED lock held on the specified
-** file by this or any other process. If such a lock is held, return
-** non-zero, otherwise zero.
-*/
-static int os2CheckReservedLock( sqlite3_file *id, int *pOut ){
-  int r = 0;
-  os2File *pFile = (os2File*)id;
-  assert( pFile!=0 );
-  if( pFile->locktype>=RESERVED_LOCK ){
-    r = 1;
-    OSTRACE3( "TEST WR-LOCK %d %d (local)\n", pFile->h, r );
-  }else{
-    FILELOCK  LockArea,
-              UnlockArea;
-    APIRET rc = NO_ERROR;
-    memset(&LockArea, 0, sizeof(LockArea));
-    memset(&UnlockArea, 0, sizeof(UnlockArea));
-    LockArea.lOffset = RESERVED_BYTE;
-    LockArea.lRange = 1L;
-    UnlockArea.lOffset = 0L;
-    UnlockArea.lRange = 0L;
-    rc = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-    OSTRACE3( "TEST WR-LOCK %d lock reserved byte rc=%d\n", pFile->h, rc );
-    if( rc == NO_ERROR ){
-      APIRET rcu = NO_ERROR; /* return code for unlocking */
-      LockArea.lOffset = 0L;
-      LockArea.lRange = 0L;
-      UnlockArea.lOffset = RESERVED_BYTE;
-      UnlockArea.lRange = 1L;
-      rcu = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-      OSTRACE3( "TEST WR-LOCK %d unlock reserved byte r=%d\n", pFile->h, rcu );
-    }
-    r = !(rc == NO_ERROR);
-    OSTRACE3( "TEST WR-LOCK %d %d (remote)\n", pFile->h, r );
-  }
-  *pOut = r;
-  return SQLITE_OK;
-}
-
-/*
-** Lower the locking level on file descriptor id to locktype.  locktype
-** must be either NO_LOCK or SHARED_LOCK.
-**
-** If the locking level of the file descriptor is already at or below
-** the requested locking level, this routine is a no-op.
-**
-** It is not possible for this routine to fail if the second argument
-** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
-** might return SQLITE_IOERR;
-*/
-static int os2Unlock( sqlite3_file *id, int locktype ){
-  int type;
-  os2File *pFile = (os2File*)id;
-  APIRET rc = SQLITE_OK;
-  APIRET res = NO_ERROR;
-  FILELOCK  LockArea,
-            UnlockArea;
-  memset(&LockArea, 0, sizeof(LockArea));
-  memset(&UnlockArea, 0, sizeof(UnlockArea));
-  assert( pFile!=0 );
-  assert( locktype<=SHARED_LOCK );
-  OSTRACE4( "UNLOCK %d to %d was %d\n", pFile->h, locktype, pFile->locktype );
-  type = pFile->locktype;
-  if( type>=EXCLUSIVE_LOCK ){
-    LockArea.lOffset = 0L;
-    LockArea.lRange = 0L;
-    UnlockArea.lOffset = SHARED_FIRST;
-    UnlockArea.lRange = SHARED_SIZE;
-    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-    OSTRACE3( "UNLOCK %d exclusive lock res=%d\n", pFile->h, res );
-    if( locktype==SHARED_LOCK && getReadLock(pFile) != NO_ERROR ){
-      /* This should never happen.  We should always be able to
-      ** reacquire the read lock */
-      OSTRACE3( "UNLOCK %d to %d getReadLock() failed\n", pFile->h, locktype );
-      rc = SQLITE_IOERR_UNLOCK;
-    }
-  }
-  if( type>=RESERVED_LOCK ){
-    LockArea.lOffset = 0L;
-    LockArea.lRange = 0L;
-    UnlockArea.lOffset = RESERVED_BYTE;
-    UnlockArea.lRange = 1L;
-    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-    OSTRACE3( "UNLOCK %d reserved res=%d\n", pFile->h, res );
-  }
-  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
-    res = unlockReadLock(pFile);
-    OSTRACE5( "UNLOCK %d is %d want %d res=%d\n", pFile->h, type, locktype, res );
-  }
-  if( type>=PENDING_LOCK ){
-    LockArea.lOffset = 0L;
-    LockArea.lRange = 0L;
-    UnlockArea.lOffset = PENDING_BYTE;
-    UnlockArea.lRange = 1L;
-    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
-    OSTRACE3( "UNLOCK %d pending res=%d\n", pFile->h, res );
-  }
-  pFile->locktype = locktype;
-  OSTRACE3( "UNLOCK %d now %d\n", pFile->h, pFile->locktype );
-  return rc;
-}
-
-/*
-** Control and query of the open file handle.
-*/
-static int os2FileControl(sqlite3_file *id, int op, void *pArg){
-  switch( op ){
-    case SQLITE_FCNTL_LOCKSTATE: {
-      *(int*)pArg = ((os2File*)id)->locktype;
-      OSTRACE3( "FCNTL_LOCKSTATE %d lock=%d\n", ((os2File*)id)->h, ((os2File*)id)->locktype );
-      return SQLITE_OK;
-    }
-  }
-  return SQLITE_ERROR;
-}
-
-/*
-** Return the sector size in bytes of the underlying block device for
-** the specified file. This is almost always 512 bytes, but may be
-** larger for some devices.
-**
-** SQLite code assumes this function cannot fail. It also assumes that
-** if two files are created in the same file-system directory (i.e.
-** a database and its journal file) that the sector size will be the
-** same for both.
-*/
-static int os2SectorSize(sqlite3_file *id){
-  return SQLITE_DEFAULT_SECTOR_SIZE;
-}
-
-/*
-** Return a vector of device characteristics.
-*/
-static int os2DeviceCharacteristics(sqlite3_file *id){
-  return 0;
-}
-
-
-/*
-** Character set conversion objects used by conversion routines.
-*/
-static UconvObject ucUtf8 = NULL; /* convert between UTF-8 and UCS-2 */
-static UconvObject uclCp = NULL;  /* convert between local codepage and UCS-2 */
-
-/*
-** Helper function to initialize the conversion objects from and to UTF-8.
-*/
-static void initUconvObjects( void ){
-  if( UniCreateUconvObject( UTF_8, &ucUtf8 ) != ULS_SUCCESS )
-    ucUtf8 = NULL;
-  if ( UniCreateUconvObject( (UniChar *)L"@path=yes", &uclCp ) != ULS_SUCCESS )
-    uclCp = NULL;
-}
-
-/*
-** Helper function to free the conversion objects from and to UTF-8.
-*/
-static void freeUconvObjects( void ){
-  if ( ucUtf8 )
-    UniFreeUconvObject( ucUtf8 );
-  if ( uclCp )
-    UniFreeUconvObject( uclCp );
-  ucUtf8 = NULL;
-  uclCp = NULL;
-}
-
-/*
-** Helper function to convert UTF-8 filenames to local OS/2 codepage.
-** The two-step process: first convert the incoming UTF-8 string
-** into UCS-2 and then from UCS-2 to the current codepage.
-** The returned char pointer has to be freed.
-*/
-static char *convertUtf8PathToCp( const char *in ){
-  UniChar tempPath[CCHMAXPATH];
-  char *out = (char *)calloc( CCHMAXPATH, 1 );
-
-  if( !out )
-    return NULL;
-
-  if( !ucUtf8 || !uclCp )
-    initUconvObjects();
-
-  /* determine string for the conversion of UTF-8 which is CP1208 */
-  if( UniStrToUcs( ucUtf8, tempPath, (char *)in, CCHMAXPATH ) != ULS_SUCCESS )
-    return out; /* if conversion fails, return the empty string */
-
-  /* conversion for current codepage which can be used for paths */
-  UniStrFromUcs( uclCp, out, tempPath, CCHMAXPATH );
-
-  return out;
-}
-
-/*
-** Helper function to convert filenames from local codepage to UTF-8.
-** The two-step process: first convert the incoming codepage-specific
-** string into UCS-2 and then from UCS-2 to the codepage of UTF-8.
-** The returned char pointer has to be freed.
-**
-** This function is non-static to be able to use this in shell.c and
-** similar applications that take command line arguments.
-*/
-char *convertCpPathToUtf8( const char *in ){
-  UniChar tempPath[CCHMAXPATH];
-  char *out = (char *)calloc( CCHMAXPATH, 1 );
-
-  if( !out )
-    return NULL;
-
-  if( !ucUtf8 || !uclCp )
-    initUconvObjects();
-
-  /* conversion for current codepage which can be used for paths */
-  if( UniStrToUcs( uclCp, tempPath, (char *)in, CCHMAXPATH ) != ULS_SUCCESS )
-    return out; /* if conversion fails, return the empty string */
-
-  /* determine string for the conversion of UTF-8 which is CP1208 */
-  UniStrFromUcs( ucUtf8, out, tempPath, CCHMAXPATH );
-
-  return out;
-}
-
-/*
-** This vector defines all the methods that can operate on an
-** sqlite3_file for os2.
-*/
-static const sqlite3_io_methods os2IoMethod = {
-  1,                        /* iVersion */
-  os2Close,
-  os2Read,
-  os2Write,
-  os2Truncate,
-  os2Sync,
-  os2FileSize,
-  os2Lock,
-  os2Unlock,
-  os2CheckReservedLock,
-  os2FileControl,
-  os2SectorSize,
-  os2DeviceCharacteristics
-};
-
-/***************************************************************************
-** Here ends the I/O methods that form the sqlite3_io_methods object.
-**
-** The next block of code implements the VFS methods.
-****************************************************************************/
-
-/*
-** Create a temporary file name in zBuf.  zBuf must be big enough to
-** hold at pVfs->mxPathname characters.
-*/
-static int getTempname(int nBuf, char *zBuf ){
-  static const unsigned char zChars[] =
-    "abcdefghijklmnopqrstuvwxyz"
-    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-    "0123456789";
-  int i, j;
-  char zTempPathBuf[3];
-  PSZ zTempPath = (PSZ)&zTempPathBuf;
-  if( sqlite3_temp_directory ){
-    zTempPath = sqlite3_temp_directory;
-  }else{
-    if( DosScanEnv( (PSZ)"TEMP", &zTempPath ) ){
-      if( DosScanEnv( (PSZ)"TMP", &zTempPath ) ){
-        if( DosScanEnv( (PSZ)"TMPDIR", &zTempPath ) ){
-           ULONG ulDriveNum = 0, ulDriveMap = 0;
-           DosQueryCurrentDisk( &ulDriveNum, &ulDriveMap );
-           sprintf( (char*)zTempPath, "%c:", (char)( 'A' + ulDriveNum - 1 ) );
-        }
-      }
-    }
-  }
-  /* Strip off a trailing slashes or backslashes, otherwise we would get *
-   * multiple (back)slashes which causes DosOpen() to fail.              *
-   * Trailing spaces are not allowed, either.                            */
-  j = sqlite3Strlen30(zTempPath);
-  while( j > 0 && ( zTempPath[j-1] == '\\' || zTempPath[j-1] == '/'
-                    || zTempPath[j-1] == ' ' ) ){
-    j--;
-  }
-  zTempPath[j] = '\0';
-  if( !sqlite3_temp_directory ){
-    char *zTempPathUTF = convertCpPathToUtf8( zTempPath );
-    sqlite3_snprintf( nBuf-30, zBuf,
-                      "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPathUTF );
-    free( zTempPathUTF );
-  }else{
-    sqlite3_snprintf( nBuf-30, zBuf,
-                      "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath );
-  }
-  j = sqlite3Strlen30( zBuf );
-  sqlite3_randomness( 20, &zBuf[j] );
-  for( i = 0; i < 20; i++, j++ ){
-    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
-  }
-  zBuf[j] = 0;
-  OSTRACE2( "TEMP FILENAME: %s\n", zBuf );
-  return SQLITE_OK;
-}
-
-
-/*
-** Turn a relative pathname into a full pathname.  Write the full
-** pathname into zFull[].  zFull[] will be at least pVfs->mxPathname
-** bytes in size.
-*/
-static int os2FullPathname(
-  sqlite3_vfs *pVfs,          /* Pointer to vfs object */
-  const char *zRelative,      /* Possibly relative input path */
-  int nFull,                  /* Size of output buffer in bytes */
-  char *zFull                 /* Output buffer */
-){
-  char *zRelativeCp = convertUtf8PathToCp( zRelative );
-  char zFullCp[CCHMAXPATH] = "\0";
-  char *zFullUTF;
-  APIRET rc = DosQueryPathInfo( zRelativeCp, FIL_QUERYFULLNAME, zFullCp,
-                                CCHMAXPATH );
-  free( zRelativeCp );
-  zFullUTF = convertCpPathToUtf8( zFullCp );
-  sqlite3_snprintf( nFull, zFull, zFullUTF );
-  free( zFullUTF );
-  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
-}
-
-
-/*
-** Open a file.
-*/
-static int os2Open(
-  sqlite3_vfs *pVfs,            /* Not used */
-  const char *zName,            /* Name of the file */
-  sqlite3_file *id,             /* Write the SQLite file handle here */
-  int flags,                    /* Open mode flags */
-  int *pOutFlags                /* Status return flags */
-){
-  HFILE h;
-  ULONG ulFileAttribute = FILE_NORMAL;
-  ULONG ulOpenFlags = 0;
-  ULONG ulOpenMode = 0;
-  os2File *pFile = (os2File*)id;
-  APIRET rc = NO_ERROR;
-  ULONG ulAction;
-  char *zNameCp;
-  char zTmpname[CCHMAXPATH+1];    /* Buffer to hold name of temp file */
-
-  /* If the second argument to this function is NULL, generate a 
-  ** temporary file name to use 
-  */
-  if( !zName ){
-    int rc = getTempname(CCHMAXPATH+1, zTmpname);
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
-    zName = zTmpname;
-  }
-
-
-  memset( pFile, 0, sizeof(*pFile) );
-
-  OSTRACE2( "OPEN want %d\n", flags );
-
-  if( flags & SQLITE_OPEN_READWRITE ){
-    ulOpenMode |= OPEN_ACCESS_READWRITE;
-    OSTRACE1( "OPEN read/write\n" );
-  }else{
-    ulOpenMode |= OPEN_ACCESS_READONLY;
-    OSTRACE1( "OPEN read only\n" );
-  }
-
-  if( flags & SQLITE_OPEN_CREATE ){
-    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_CREATE_IF_NEW;
-    OSTRACE1( "OPEN open new/create\n" );
-  }else{
-    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_FAIL_IF_NEW;
-    OSTRACE1( "OPEN open existing\n" );
-  }
-
-  if( flags & SQLITE_OPEN_MAIN_DB ){
-    ulOpenMode |= OPEN_SHARE_DENYNONE;
-    OSTRACE1( "OPEN share read/write\n" );
-  }else{
-    ulOpenMode |= OPEN_SHARE_DENYWRITE;
-    OSTRACE1( "OPEN share read only\n" );
-  }
-
-  if( flags & SQLITE_OPEN_DELETEONCLOSE ){
-    char pathUtf8[CCHMAXPATH];
-#ifdef NDEBUG /* when debugging we want to make sure it is deleted */
-    ulFileAttribute = FILE_HIDDEN;
-#endif
-    os2FullPathname( pVfs, zName, CCHMAXPATH, pathUtf8 );
-    pFile->pathToDel = convertUtf8PathToCp( pathUtf8 );
-    OSTRACE1( "OPEN hidden/delete on close file attributes\n" );
-  }else{
-    pFile->pathToDel = NULL;
-    OSTRACE1( "OPEN normal file attribute\n" );
-  }
-
-  /* always open in random access mode for possibly better speed */
-  ulOpenMode |= OPEN_FLAGS_RANDOM;
-  ulOpenMode |= OPEN_FLAGS_FAIL_ON_ERROR;
-  ulOpenMode |= OPEN_FLAGS_NOINHERIT;
-
-  zNameCp = convertUtf8PathToCp( zName );
-  rc = DosOpen( (PSZ)zNameCp,
-                &h,
-                &ulAction,
-                0L,
-                ulFileAttribute,
-                ulOpenFlags,
-                ulOpenMode,
-                (PEAOP2)NULL );
-  free( zNameCp );
-  if( rc != NO_ERROR ){
-    OSTRACE7( "OPEN Invalid handle rc=%d: zName=%s, ulAction=%#lx, ulAttr=%#lx, ulFlags=%#lx, ulMode=%#lx\n",
-              rc, zName, ulAction, ulFileAttribute, ulOpenFlags, ulOpenMode );
-    if( pFile->pathToDel )
-      free( pFile->pathToDel );
-    pFile->pathToDel = NULL;
-    if( flags & SQLITE_OPEN_READWRITE ){
-      OSTRACE2( "OPEN %d Invalid handle\n", ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE) );
-      return os2Open( pVfs, zName, id,
-                      ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE),
-                      pOutFlags );
-    }else{
-      return SQLITE_CANTOPEN;
-    }
-  }
-
-  if( pOutFlags ){
-    *pOutFlags = flags & SQLITE_OPEN_READWRITE ? SQLITE_OPEN_READWRITE : SQLITE_OPEN_READONLY;
-  }
-
-  pFile->pMethod = &os2IoMethod;
-  pFile->h = h;
-  OpenCounter(+1);
-  OSTRACE3( "OPEN %d pOutFlags=%d\n", pFile->h, pOutFlags );
-  return SQLITE_OK;
-}
-
-/*
-** Delete the named file.
-*/
-static int os2Delete(
-  sqlite3_vfs *pVfs,                     /* Not used on os2 */
-  const char *zFilename,                 /* Name of file to delete */
-  int syncDir                            /* Not used on os2 */
-){
-  APIRET rc = NO_ERROR;
-  char *zFilenameCp = convertUtf8PathToCp( zFilename );
-  SimulateIOError( return SQLITE_IOERR_DELETE );
-  rc = DosDelete( (PSZ)zFilenameCp );
-  free( zFilenameCp );
-  OSTRACE2( "DELETE \"%s\"\n", zFilename );
-  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR_DELETE;
-}
-
-/*
-** Check the existance and status of a file.
-*/
-static int os2Access(
-  sqlite3_vfs *pVfs,        /* Not used on os2 */
-  const char *zFilename,    /* Name of file to check */
-  int flags,                /* Type of test to make on this file */
-  int *pOut                 /* Write results here */
-){
-  FILESTATUS3 fsts3ConfigInfo;
-  APIRET rc = NO_ERROR;
-  char *zFilenameCp = convertUtf8PathToCp( zFilename );
-
-  memset( &fsts3ConfigInfo, 0, sizeof(fsts3ConfigInfo) );
-  rc = DosQueryPathInfo( (PSZ)zFilenameCp, FIL_STANDARD,
-                         &fsts3ConfigInfo, sizeof(FILESTATUS3) );
-  free( zFilenameCp );
-  OSTRACE4( "ACCESS fsts3ConfigInfo.attrFile=%d flags=%d rc=%d\n",
-            fsts3ConfigInfo.attrFile, flags, rc );
-  switch( flags ){
-    case SQLITE_ACCESS_READ:
-    case SQLITE_ACCESS_EXISTS:
-      rc = (rc == NO_ERROR);
-      OSTRACE3( "ACCESS %s access of read and exists  rc=%d\n", zFilename, rc );
-      break;
-    case SQLITE_ACCESS_READWRITE:
-      rc = (rc == NO_ERROR) && ( (fsts3ConfigInfo.attrFile & FILE_READONLY) == 0 );
-      OSTRACE3( "ACCESS %s access of read/write  rc=%d\n", zFilename, rc );
-      break;
-    default:
-      assert( !"Invalid flags argument" );
-  }
-  *pOut = rc;
-  return SQLITE_OK;
-}
-
-
-#ifndef SQLITE_OMIT_LOAD_EXTENSION
-/*
-** Interfaces for opening a shared library, finding entry points
-** within the shared library, and closing the shared library.
-*/
-/*
-** Interfaces for opening a shared library, finding entry points
-** within the shared library, and closing the shared library.
-*/
-static void *os2DlOpen(sqlite3_vfs *pVfs, const char *zFilename){
-  UCHAR loadErr[256];
-  HMODULE hmod;
-  APIRET rc;
-  char *zFilenameCp = convertUtf8PathToCp(zFilename);
-  rc = DosLoadModule((PSZ)loadErr, sizeof(loadErr), zFilenameCp, &hmod);
-  free(zFilenameCp);
-  return rc != NO_ERROR ? 0 : (void*)hmod;
-}
-/*
-** A no-op since the error code is returned on the DosLoadModule call.
-** os2Dlopen returns zero if DosLoadModule is not successful.
-*/
-static void os2DlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
-/* no-op */
-}
-static void *os2DlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
-  PFN pfn;
-  APIRET rc;
-  rc = DosQueryProcAddr((HMODULE)pHandle, 0L, zSymbol, &pfn);
-  if( rc != NO_ERROR ){
-    /* if the symbol itself was not found, search again for the same
-     * symbol with an extra underscore, that might be needed depending
-     * on the calling convention */
-    char _zSymbol[256] = "_";
-    strncat(_zSymbol, zSymbol, 255);
-    rc = DosQueryProcAddr((HMODULE)pHandle, 0L, _zSymbol, &pfn);
-  }
-  return rc != NO_ERROR ? 0 : (void*)pfn;
-}
-static void os2DlClose(sqlite3_vfs *pVfs, void *pHandle){
-  DosFreeModule((HMODULE)pHandle);
-}
-#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
-  #define os2DlOpen 0
-  #define os2DlError 0
-  #define os2DlSym 0
-  #define os2DlClose 0
-#endif
-
-
-/*
-** Write up to nBuf bytes of randomness into zBuf.
-*/
-static int os2Randomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf ){
-  int n = 0;
-#if defined(SQLITE_TEST)
-  n = nBuf;
-  memset(zBuf, 0, nBuf);
-#else
-  int sizeofULong = sizeof(ULONG);
-  if( (int)sizeof(DATETIME) <= nBuf - n ){
-    DATETIME x;
-    DosGetDateTime(&x);
-    memcpy(&zBuf[n], &x, sizeof(x));
-    n += sizeof(x);
-  }
-
-  if( sizeofULong <= nBuf - n ){
-    PPIB ppib;
-    DosGetInfoBlocks(NULL, &ppib);
-    memcpy(&zBuf[n], &ppib->pib_ulpid, sizeofULong);
-    n += sizeofULong;
-  }
-
-  if( sizeofULong <= nBuf - n ){
-    PTIB ptib;
-    DosGetInfoBlocks(&ptib, NULL);
-    memcpy(&zBuf[n], &ptib->tib_ptib2->tib2_ultid, sizeofULong);
-    n += sizeofULong;
-  }
-
-  /* if we still haven't filled the buffer yet the following will */
-  /* grab everything once instead of making several calls for a single item */
-  if( sizeofULong <= nBuf - n ){
-    ULONG ulSysInfo[QSV_MAX];
-    DosQuerySysInfo(1L, QSV_MAX, ulSysInfo, sizeofULong * QSV_MAX);
-
-    memcpy(&zBuf[n], &ulSysInfo[QSV_MS_COUNT - 1], sizeofULong);
-    n += sizeofULong;
-
-    if( sizeofULong <= nBuf - n ){
-      memcpy(&zBuf[n], &ulSysInfo[QSV_TIMER_INTERVAL - 1], sizeofULong);
-      n += sizeofULong;
-    }
-    if( sizeofULong <= nBuf - n ){
-      memcpy(&zBuf[n], &ulSysInfo[QSV_TIME_LOW - 1], sizeofULong);
-      n += sizeofULong;
-    }
-    if( sizeofULong <= nBuf - n ){
-      memcpy(&zBuf[n], &ulSysInfo[QSV_TIME_HIGH - 1], sizeofULong);
-      n += sizeofULong;
-    }
-    if( sizeofULong <= nBuf - n ){
-      memcpy(&zBuf[n], &ulSysInfo[QSV_TOTAVAILMEM - 1], sizeofULong);
-      n += sizeofULong;
-    }
-  }
-#endif
-
-  return n;
-}
-
-/*
-** Sleep for a little while.  Return the amount of time slept.
-** The argument is the number of microseconds we want to sleep.
-** The return value is the number of microseconds of sleep actually
-** requested from the underlying operating system, a number which
-** might be greater than or equal to the argument, but not less
-** than the argument.
-*/
-static int os2Sleep( sqlite3_vfs *pVfs, int microsec ){
-  DosSleep( (microsec/1000) );
-  return microsec;
-}
-
-/*
-** The following variable, if set to a non-zero value, becomes the result
-** returned from sqlite3OsCurrentTime().  This is used for testing.
-*/
-#ifdef SQLITE_TEST
-SQLITE_API int sqlite3_current_time = 0;
-#endif
-
-/*
-** Find the current time (in Universal Coordinated Time).  Write the
-** current time and date as a Julian Day number into *prNow and
-** return 0.  Return 1 if the time and date cannot be found.
-*/
-int os2CurrentTime( sqlite3_vfs *pVfs, double *prNow ){
-  double now;
-  SHORT minute; /* needs to be able to cope with negative timezone offset */
-  USHORT second, hour,
-         day, month, year;
-  DATETIME dt;
-  DosGetDateTime( &dt );
-  second = (USHORT)dt.seconds;
-  minute = (SHORT)dt.minutes + dt.timezone;
-  hour = (USHORT)dt.hours;
-  day = (USHORT)dt.day;
-  month = (USHORT)dt.month;
-  year = (USHORT)dt.year;
-
-  /* Calculations from http://www.astro.keele.ac.uk/~rno/Astronomy/hjd.html
-     http://www.astro.keele.ac.uk/~rno/Astronomy/hjd-0.1.c */
-  /* Calculate the Julian days */
-  now = day - 32076 +
-    1461*(year + 4800 + (month - 14)/12)/4 +
-    367*(month - 2 - (month - 14)/12*12)/12 -
-    3*((year + 4900 + (month - 14)/12)/100)/4;
-
-  /* Add the fractional hours, mins and seconds */
-  now += (hour + 12.0)/24.0;
-  now += minute/1440.0;
-  now += second/86400.0;
-  *prNow = now;
-#ifdef SQLITE_TEST
-  if( sqlite3_current_time ){
-    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
-  }
-#endif
-  return 0;
-}
-
-static int os2GetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
-  return 0;
-}
-
-/*
-** Initialize and deinitialize the operating system interface.
-*/
-SQLITE_API int sqlite3_os_init(void){
-  static sqlite3_vfs os2Vfs = {
-    1,                 /* iVersion */
-    sizeof(os2File),   /* szOsFile */
-    CCHMAXPATH,        /* mxPathname */
-    0,                 /* pNext */
-    "os2",             /* zName */
-    0,                 /* pAppData */
-
-    os2Open,           /* xOpen */
-    os2Delete,         /* xDelete */
-    os2Access,         /* xAccess */
-    os2FullPathname,   /* xFullPathname */
-    os2DlOpen,         /* xDlOpen */
-    os2DlError,        /* xDlError */
-    os2DlSym,          /* xDlSym */
-    os2DlClose,        /* xDlClose */
-    os2Randomness,     /* xRandomness */
-    os2Sleep,          /* xSleep */
-    os2CurrentTime,    /* xCurrentTime */
-    os2GetLastError    /* xGetLastError */
-  };
-  sqlite3_vfs_register(&os2Vfs, 1);
-  initUconvObjects();
-  return SQLITE_OK;
-}
-SQLITE_API int sqlite3_os_end(void){
-  freeUconvObjects();
-  return SQLITE_OK;
-}
-
-#endif /* SQLITE_OS_OS2 */
-
-/************** End of os_os2.c **********************************************/
 /************** Begin file os_unix.c *****************************************/
 /*
 ** 2004 May 22
@@ -21588,8 +22600,6 @@ SQLITE_API int sqlite3_os_end(void){
 **   *  Locking primitives for the proxy uber-locking-method. (MacOSX only)
 **   *  Definitions of sqlite3_vfs objects for all locking methods
 **      plus implementations of sqlite3_os_init() and sqlite3_os_end().
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #if SQLITE_OS_UNIX              /* This file is used on unix only */
 
@@ -21663,8 +22673,13 @@ SQLITE_API int sqlite3_os_end(void){
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
+/* #include <time.h> */
 #include <sys/time.h>
 #include <errno.h>
+#ifndef SQLITE_OMIT_WAL
+#include <sys/mman.h>
+#endif
+
 
 #if SQLITE_ENABLE_LOCKING_STYLE
 # include <sys/ioctl.h>
@@ -21674,15 +22689,28 @@ SQLITE_API int sqlite3_os_end(void){
 # else
 #  include <sys/file.h>
 #  include <sys/param.h>
-#  include <sys/mount.h>
 # endif
 #endif /* SQLITE_ENABLE_LOCKING_STYLE */
 
+#if defined(__APPLE__) || (SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS)
+# include <sys/mount.h>
+#endif
+
+#ifdef HAVE_UTIME
+# include <utime.h>
+#endif
+
+/*
+** Allowed values of unixFile.fsFlags
+*/
+#define SQLITE_FSFLAGS_IS_MSDOS     0x1
+
 /*
 ** If we are to be thread-safe, include the pthreads header and define
 ** the SQLITE_UNIX_THREADS macro.
 */
 #if SQLITE_THREADSAFE
+/* # include <pthread.h> */
 # define SQLITE_UNIX_THREADS 1
 #endif
 
@@ -21694,8 +22722,8 @@ SQLITE_API int sqlite3_os_end(void){
 #endif
 
 /*
- ** Default permissions when creating auto proxy dir
- */
+** Default permissions when creating auto proxy dir
+*/
 #ifndef SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
 # define SQLITE_DEFAULT_PROXYDIR_PERMISSIONS 0755
 #endif
@@ -21711,6 +22739,23 @@ SQLITE_API int sqlite3_os_end(void){
 */
 #define IS_LOCK_ERROR(x)  ((x != SQLITE_OK) && (x != SQLITE_BUSY))
 
+/* Forward references */
+typedef struct unixShm unixShm;               /* Connection shared memory */
+typedef struct unixShmNode unixShmNode;       /* Shared memory instance */
+typedef struct unixInodeInfo unixInodeInfo;   /* An i-node */
+typedef struct UnixUnusedFd UnixUnusedFd;     /* An unused file descriptor */
+
+/*
+** Sometimes, after a file handle is closed by SQLite, the file descriptor
+** cannot be closed immediately. In these cases, instances of the following
+** structure are used to store the file descriptor while waiting for an
+** opportunity to either close or reuse it.
+*/
+struct UnixUnusedFd {
+  int fd;                   /* File descriptor to close */
+  int flags;                /* Flags this file descriptor was opened with */
+  UnixUnusedFd *pNext;      /* Next unused file descriptor on same file */
+};
 
 /*
 ** The unixFile structure is subclass of sqlite3_file specific to the unix
@@ -21719,22 +22764,27 @@ SQLITE_API int sqlite3_os_end(void){
 typedef struct unixFile unixFile;
 struct unixFile {
   sqlite3_io_methods const *pMethod;  /* Always the first entry */
-  struct unixOpenCnt *pOpen;       /* Info about all open fd's on this inode */
-  struct unixLockInfo *pLock;      /* Info about locks on this inode */
-  int h;                           /* The file descriptor */
-  int dirfd;                       /* File descriptor for the directory */
-  unsigned char locktype;          /* The type of lock held on this fd */
-  int lastErrno;                   /* The unix errno from the last I/O error */
-  void *lockingContext;            /* Locking style specific state */
-  int openFlags;                   /* The flags specified at open */
-#if SQLITE_THREADSAFE && defined(__linux__)
-  pthread_t tid;                   /* The thread that "owns" this unixFile */
+  sqlite3_vfs *pVfs;                  /* The VFS that created this unixFile */
+  unixInodeInfo *pInode;              /* Info about locks on this inode */
+  int h;                              /* The file descriptor */
+  unsigned char eFileLock;            /* The type of lock held on this fd */
+  unsigned short int ctrlFlags;       /* Behavioral bits.  UNIXFILE_* flags */
+  int lastErrno;                      /* The unix errno from last I/O error */
+  void *lockingContext;               /* Locking style specific state */
+  UnixUnusedFd *pUnused;              /* Pre-allocated UnixUnusedFd */
+  const char *zPath;                  /* Name of the file */
+  unixShm *pShm;                      /* Shared memory segment information */
+  int szChunk;                        /* Configured by FCNTL_CHUNK_SIZE */
+#if SQLITE_ENABLE_LOCKING_STYLE
+  int openFlags;                      /* The flags specified at open() */
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
+  unsigned fsFlags;                   /* cached details from statfs() */
 #endif
 #if OS_VXWORKS
-  int isDelete;                    /* Delete on close if true */
-  struct vxworksFileId *pId;       /* Unique file ID */
+  struct vxworksFileId *pId;          /* Unique file ID */
 #endif
-#ifndef NDEBUG
+#ifdef SQLITE_DEBUG
   /* The next group of variables are used to track whether or not the
   ** transaction counter in bytes 24-27 of database files are updated
   ** whenever any part of the database changes.  An assertion fault will
@@ -21754,6 +22804,22 @@ struct unixFile {
 #endif
 };
 
+/*
+** Allowed values for the unixFile.ctrlFlags bitmask:
+*/
+#define UNIXFILE_EXCL        0x01     /* Connections from one process only */
+#define UNIXFILE_RDONLY      0x02     /* Connection is read only */
+#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
+#ifndef SQLITE_DISABLE_DIRSYNC
+# define UNIXFILE_DIRSYNC    0x08     /* Directory sync needed */
+#else
+# define UNIXFILE_DIRSYNC    0x00
+#endif
+#define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+#define UNIXFILE_DELETE      0x20     /* Delete on close */
+#define UNIXFILE_URI         0x40     /* Filename might have query parameters */
+#define UNIXFILE_NOLOCK      0x80     /* Do no file locking */
+
 /*
 ** Include code that is common to all os_*.c files
 */
@@ -21777,8 +22843,6 @@ struct unixFile {
 **
 ** This file should be #included by the os_*.c files only.  It is not a
 ** general purpose header file.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _OS_COMMON_H_
 #define _OS_COMMON_H_
@@ -21792,34 +22856,14 @@ struct unixFile {
 # error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
 #endif
 
-
-/*
- * When testing, this global variable stores the location of the
- * pending-byte in the database file.
- */
-#ifdef SQLITE_TEST
-SQLITE_API unsigned int sqlite3_pending_byte = 0x40000000;
-#endif
-
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE int sqlite3OSTrace = 0;
-#define OSTRACE1(X)         if( sqlite3OSTrace ) sqlite3DebugPrintf(X)
-#define OSTRACE2(X,Y)       if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y)
-#define OSTRACE3(X,Y,Z)     if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z)
-#define OSTRACE4(X,Y,Z,A)   if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A)
-#define OSTRACE5(X,Y,Z,A,B) if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A,B)
-#define OSTRACE6(X,Y,Z,A,B,C) \
-    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
-#define OSTRACE7(X,Y,Z,A,B,C,D) \
-    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+# ifndef SQLITE_DEBUG_OS_TRACE
+#   define SQLITE_DEBUG_OS_TRACE 0
+# endif
+  int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
+# define OSTRACE(X)          if( sqlite3OSTrace ) sqlite3DebugPrintf X
 #else
-#define OSTRACE1(X)
-#define OSTRACE2(X,Y)
-#define OSTRACE3(X,Y,Z)
-#define OSTRACE4(X,Y,Z,A)
-#define OSTRACE5(X,Y,Z,A,B)
-#define OSTRACE6(X,Y,Z,A,B,C)
-#define OSTRACE7(X,Y,Z,A,B,C,D)
+# define OSTRACE(X)
 #endif
 
 /*
@@ -21848,8 +22892,6 @@ SQLITE_PRIVATE int sqlite3OSTrace = 0;
 **
 ** This file contains inline asm code for retrieving "high-performance"
 ** counters for x86 class CPUs.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _HWTIME_H_
 #define _HWTIME_H_
@@ -22008,16 +23050,6 @@ SQLITE_API int sqlite3_open_file_count = 0;
 # define O_BINARY 0
 #endif
 
-/*
-** The DJGPP compiler environment looks mostly like Unix, but it
-** lacks the fcntl() system call.  So redefine fcntl() to be something
-** that always succeeds.  This means that locking does not occur under
-** DJGPP.  But it is DOS - what did you expect?
-*/
-#ifdef __DJGPP__
-# define fcntl(A,B,C) 0
-#endif
-
 /*
 ** The threadid macro resolves to the thread-id or to 0.  Used for
 ** testing and debugging only.
@@ -22028,9 +23060,285 @@ SQLITE_API int sqlite3_open_file_count = 0;
 #define threadid 0
 #endif
 
+/*
+** Different Unix systems declare open() in different ways.  Same use
+** open(const char*,int,mode_t).  Others use open(const char*,int,...).
+** The difference is important when using a pointer to the function.
+**
+** The safest way to deal with the problem is to always use this wrapper
+** which always has the same well-defined interface.
+*/
+static int posixOpen(const char *zFile, int flags, int mode){
+  return open(zFile, flags, mode);
+}
 
 /*
-** Helper functions to obtain and relinquish the global mutex.
+** On some systems, calls to fchown() will trigger a message in a security
+** log if they come from non-root processes.  So avoid calling fchown() if
+** we are not running as root.
+*/
+static int posixFchown(int fd, uid_t uid, gid_t gid){
+  return geteuid() ? 0 : fchown(fd,uid,gid);
+}
+
+/* Forward reference */
+static int openDirectory(const char*, int*);
+
+/*
+** Many system calls are accessed through pointer-to-functions so that
+** they may be overridden at runtime to facilitate fault injection during
+** testing and sandboxing.  The following array holds the names and pointers
+** to all overrideable system calls.
+*/
+static struct unix_syscall {
+  const char *zName;            /* Name of the sytem call */
+  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
+  sqlite3_syscall_ptr pDefault; /* Default value */
+} aSyscall[] = {
+  { "open",         (sqlite3_syscall_ptr)posixOpen,  0  },
+#define osOpen      ((int(*)(const char*,int,int))aSyscall[0].pCurrent)
+
+  { "close",        (sqlite3_syscall_ptr)close,      0  },
+#define osClose     ((int(*)(int))aSyscall[1].pCurrent)
+
+  { "access",       (sqlite3_syscall_ptr)access,     0  },
+#define osAccess    ((int(*)(const char*,int))aSyscall[2].pCurrent)
+
+  { "getcwd",       (sqlite3_syscall_ptr)getcwd,     0  },
+#define osGetcwd    ((char*(*)(char*,size_t))aSyscall[3].pCurrent)
+
+  { "stat",         (sqlite3_syscall_ptr)stat,       0  },
+#define osStat      ((int(*)(const char*,struct stat*))aSyscall[4].pCurrent)
+
+/*
+** The DJGPP compiler environment looks mostly like Unix, but it
+** lacks the fcntl() system call.  So redefine fcntl() to be something
+** that always succeeds.  This means that locking does not occur under
+** DJGPP.  But it is DOS - what did you expect?
+*/
+#ifdef __DJGPP__
+  { "fstat",        0,                 0  },
+#define osFstat(a,b,c)    0
+#else     
+  { "fstat",        (sqlite3_syscall_ptr)fstat,      0  },
+#define osFstat     ((int(*)(int,struct stat*))aSyscall[5].pCurrent)
+#endif
+
+  { "ftruncate",    (sqlite3_syscall_ptr)ftruncate,  0  },
+#define osFtruncate ((int(*)(int,off_t))aSyscall[6].pCurrent)
+
+  { "fcntl",        (sqlite3_syscall_ptr)fcntl,      0  },
+#define osFcntl     ((int(*)(int,int,...))aSyscall[7].pCurrent)
+
+  { "read",         (sqlite3_syscall_ptr)read,       0  },
+#define osRead      ((ssize_t(*)(int,void*,size_t))aSyscall[8].pCurrent)
+
+#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE
+  { "pread",        (sqlite3_syscall_ptr)pread,      0  },
+#else
+  { "pread",        (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPread     ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[9].pCurrent)
+
+#if defined(USE_PREAD64)
+  { "pread64",      (sqlite3_syscall_ptr)pread64,    0  },
+#else
+  { "pread64",      (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPread64   ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[10].pCurrent)
+
+  { "write",        (sqlite3_syscall_ptr)write,      0  },
+#define osWrite     ((ssize_t(*)(int,const void*,size_t))aSyscall[11].pCurrent)
+
+#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE
+  { "pwrite",       (sqlite3_syscall_ptr)pwrite,     0  },
+#else
+  { "pwrite",       (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPwrite    ((ssize_t(*)(int,const void*,size_t,off_t))\
+                    aSyscall[12].pCurrent)
+
+#if defined(USE_PREAD64)
+  { "pwrite64",     (sqlite3_syscall_ptr)pwrite64,   0  },
+#else
+  { "pwrite64",     (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPwrite64  ((ssize_t(*)(int,const void*,size_t,off_t))\
+                    aSyscall[13].pCurrent)
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+  { "fchmod",       (sqlite3_syscall_ptr)fchmod,     0  },
+#else
+  { "fchmod",       (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osFchmod    ((int(*)(int,mode_t))aSyscall[14].pCurrent)
+
+#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
+  { "fallocate",    (sqlite3_syscall_ptr)posix_fallocate,  0 },
+#else
+  { "fallocate",    (sqlite3_syscall_ptr)0,                0 },
+#endif
+#define osFallocate ((int(*)(int,off_t,off_t))aSyscall[15].pCurrent)
+
+  { "unlink",       (sqlite3_syscall_ptr)unlink,           0 },
+#define osUnlink    ((int(*)(const char*))aSyscall[16].pCurrent)
+
+  { "openDirectory",    (sqlite3_syscall_ptr)openDirectory,      0 },
+#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent)
+
+  { "mkdir",        (sqlite3_syscall_ptr)mkdir,           0 },
+#define osMkdir     ((int(*)(const char*,mode_t))aSyscall[18].pCurrent)
+
+  { "rmdir",        (sqlite3_syscall_ptr)rmdir,           0 },
+#define osRmdir     ((int(*)(const char*))aSyscall[19].pCurrent)
+
+  { "fchown",       (sqlite3_syscall_ptr)posixFchown,     0 },
+#define osFchown    ((int(*)(int,uid_t,gid_t))aSyscall[20].pCurrent)
+
+  { "umask",        (sqlite3_syscall_ptr)umask,           0 },
+#define osUmask     ((mode_t(*)(mode_t))aSyscall[21].pCurrent)
+
+}; /* End of the overrideable system calls */
+
+/*
+** This is the xSetSystemCall() method of sqlite3_vfs for all of the
+** "unix" VFSes.  Return SQLITE_OK opon successfully updating the
+** system call pointer, or SQLITE_NOTFOUND if there is no configurable
+** system call named zName.
+*/
+static int unixSetSystemCall(
+  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
+  const char *zName,            /* Name of system call to override */
+  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
+){
+  unsigned int i;
+  int rc = SQLITE_NOTFOUND;
+
+  UNUSED_PARAMETER(pNotUsed);
+  if( zName==0 ){
+    /* If no zName is given, restore all system calls to their default
+    ** settings and return NULL
+    */
+    rc = SQLITE_OK;
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( aSyscall[i].pDefault ){
+        aSyscall[i].pCurrent = aSyscall[i].pDefault;
+      }
+    }
+  }else{
+    /* If zName is specified, operate on only the one system call
+    ** specified.
+    */
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ){
+        if( aSyscall[i].pDefault==0 ){
+          aSyscall[i].pDefault = aSyscall[i].pCurrent;
+        }
+        rc = SQLITE_OK;
+        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
+        aSyscall[i].pCurrent = pNewFunc;
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the value of a system call.  Return NULL if zName is not a
+** recognized system call name.  NULL is also returned if the system call
+** is currently undefined.
+*/
+static sqlite3_syscall_ptr unixGetSystemCall(
+  sqlite3_vfs *pNotUsed,
+  const char *zName
+){
+  unsigned int i;
+
+  UNUSED_PARAMETER(pNotUsed);
+  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
+  }
+  return 0;
+}
+
+/*
+** Return the name of the first system call after zName.  If zName==NULL
+** then return the name of the first system call.  Return NULL if zName
+** is the last system call or if zName is not the name of a valid
+** system call.
+*/
+static const char *unixNextSystemCall(sqlite3_vfs *p, const char *zName){
+  int i = -1;
+
+  UNUSED_PARAMETER(p);
+  if( zName ){
+    for(i=0; i<ArraySize(aSyscall)-1; i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
+    }
+  }
+  for(i++; i<ArraySize(aSyscall); i++){
+    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
+  }
+  return 0;
+}
+
+/*
+** Invoke open().  Do so multiple times, until it either succeeds or
+** fails for some reason other than EINTR.
+**
+** If the file creation mode "m" is 0 then set it to the default for
+** SQLite.  The default is SQLITE_DEFAULT_FILE_PERMISSIONS (normally
+** 0644) as modified by the system umask.  If m is not 0, then
+** make the file creation mode be exactly m ignoring the umask.
+**
+** The m parameter will be non-zero only when creating -wal, -journal,
+** and -shm files.  We want those files to have *exactly* the same
+** permissions as their original database, unadulterated by the umask.
+** In that way, if a database file is -rw-rw-rw or -rw-rw-r-, and a
+** transaction crashes and leaves behind hot journals, then any
+** process that is able to write to the database will also be able to
+** recover the hot journals.
+*/
+static int robust_open(const char *z, int f, mode_t m){
+  int fd;
+  mode_t m2;
+  mode_t origM = 0;
+  if( m==0 ){
+    m2 = SQLITE_DEFAULT_FILE_PERMISSIONS;
+  }else{
+    m2 = m;
+    origM = osUmask(0);
+  }
+  do{
+#if defined(O_CLOEXEC)
+    fd = osOpen(z,f|O_CLOEXEC,m2);
+#else
+    fd = osOpen(z,f,m2);
+#endif
+  }while( fd<0 && errno==EINTR );
+  if( m ){
+    osUmask(origM);
+  }
+#if defined(FD_CLOEXEC) && (!defined(O_CLOEXEC) || O_CLOEXEC==0)
+  if( fd>=0 ) osFcntl(fd, F_SETFD, osFcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
+#endif
+  return fd;
+}
+
+/*
+** Helper functions to obtain and relinquish the global mutex. The
+** global mutex is used to protect the unixInodeInfo and
+** vxworksFileId objects used by this file, all of which may be 
+** shared by multiple threads.
+**
+** Function unixMutexHeld() is used to assert() that the global mutex 
+** is held when required. This function is only used as part of assert() 
+** statements. e.g.
+**
+**   unixEnterMutex()
+**     assert( unixMutexHeld() );
+**   unixEnterLeave()
 */
 static void unixEnterMutex(void){
   sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
@@ -22038,21 +23346,26 @@ static void unixEnterMutex(void){
 static void unixLeaveMutex(void){
   sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
 }
-
-
 #ifdef SQLITE_DEBUG
+static int unixMutexHeld(void) {
+  return sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+#endif
+
+
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
 /*
 ** Helper function for printing out trace information from debugging
 ** binaries. This returns the string represetation of the supplied
 ** integer lock-type.
 */
-static const char *locktypeName(int locktype){
-  switch( locktype ){
-  case NO_LOCK: return "NONE";
-  case SHARED_LOCK: return "SHARED";
-  case RESERVED_LOCK: return "RESERVED";
-  case PENDING_LOCK: return "PENDING";
-  case EXCLUSIVE_LOCK: return "EXCLUSIVE";
+static const char *azFileLock(int eFileLock){
+  switch( eFileLock ){
+    case NO_LOCK: return "NONE";
+    case SHARED_LOCK: return "SHARED";
+    case RESERVED_LOCK: return "RESERVED";
+    case PENDING_LOCK: return "PENDING";
+    case EXCLUSIVE_LOCK: return "EXCLUSIVE";
   }
   return "ERROR";
 }
@@ -22076,7 +23389,7 @@ static int lockTrace(int fd, int op, struct flock *p){
   }else if( op==F_SETLK ){
     zOpName = "SETLK";
   }else{
-    s = fcntl(fd, op, p);
+    s = osFcntl(fd, op, p);
     sqlite3DebugPrintf("fcntl unknown %d %d %d\n", fd, op, s);
     return s;
   }
@@ -22090,7 +23403,7 @@ static int lockTrace(int fd, int op, struct flock *p){
     assert( 0 );
   }
   assert( p->l_whence==SEEK_SET );
-  s = fcntl(fd, op, p);
+  s = osFcntl(fd, op, p);
   savedErrno = errno;
   sqlite3DebugPrintf("fcntl %d %d %s %s %d %d %d %d\n",
      threadid, fd, zOpName, zType, (int)p->l_start, (int)p->l_len,
@@ -22098,7 +23411,7 @@ static int lockTrace(int fd, int op, struct flock *p){
   if( s==(-1) && op==F_SETLK && (p->l_type==F_RDLCK || p->l_type==F_WRLCK) ){
     struct flock l2;
     l2 = *p;
-    fcntl(fd, F_GETLK, &l2);
+    osFcntl(fd, F_GETLK, &l2);
     if( l2.l_type==F_RDLCK ){
       zType = "RDLCK";
     }else if( l2.l_type==F_WRLCK ){
@@ -22114,10 +23427,18 @@ static int lockTrace(int fd, int op, struct flock *p){
   errno = savedErrno;
   return s;
 }
-#define fcntl lockTrace
+#undef osFcntl
+#define osFcntl lockTrace
 #endif /* SQLITE_LOCK_TRACE */
 
-
+/*
+** Retry ftruncate() calls that fail due to EINTR
+*/
+static int robust_ftruncate(int h, sqlite3_int64 sz){
+  int rc;
+  do{ rc = osFtruncate(h,sz); }while( rc<0 && errno==EINTR );
+  return rc;
+}
 
 /*
 ** This routine translates a standard POSIX errno code into something
@@ -22131,9 +23452,22 @@ static int lockTrace(int fd, int op, struct flock *p){
 */
 static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) {
   switch (posixError) {
+#if 0
+  /* At one point this code was not commented out. In theory, this branch
+  ** should never be hit, as this function should only be called after
+  ** a locking-related function (i.e. fcntl()) has returned non-zero with
+  ** the value of errno as the first argument. Since a system call has failed,
+  ** errno should be non-zero.
+  **
+  ** Despite this, if errno really is zero, we still don't want to return
+  ** SQLITE_OK. The system call failed, and *some* SQLite error should be
+  ** propagated back to the caller. Commenting this branch out means errno==0
+  ** will be handled by the "default:" case below.
+  */
   case 0: 
     return SQLITE_OK;
-    
+#endif
+
   case EAGAIN:
   case ETIMEDOUT:
   case EBUSY:
@@ -22146,17 +23480,24 @@ static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) {
   case EACCES: 
     /* EACCES is like EAGAIN during locking operations, but not any other time*/
     if( (sqliteIOErr == SQLITE_IOERR_LOCK) || 
-	(sqliteIOErr == SQLITE_IOERR_UNLOCK) || 
-	(sqliteIOErr == SQLITE_IOERR_RDLOCK) ||
-	(sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) ){
+        (sqliteIOErr == SQLITE_IOERR_UNLOCK) || 
+        (sqliteIOErr == SQLITE_IOERR_RDLOCK) ||
+        (sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) ){
       return SQLITE_BUSY;
     }
     /* else fall through */
   case EPERM: 
     return SQLITE_PERM;
     
+  /* EDEADLK is only possible if a call to fcntl(F_SETLKW) is made. And
+  ** this module never makes such a call. And the code in SQLite itself 
+  ** asserts that SQLITE_IOERR_BLOCKED is never returned. For these reasons
+  ** this case is also commented out. If the system does set errno to EDEADLK,
+  ** the default SQLITE_IOERR_XXX code will be returned. */
+#if 0
   case EDEADLK:
     return SQLITE_IOERR_BLOCKED;
+#endif
     
 #if EOPNOTSUPP!=ENOTSUP
   case EOPNOTSUPP: 
@@ -22175,7 +23516,9 @@ static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) {
   case ENODEV:
   case ENXIO:
   case ENOENT:
+#ifdef ESTALE                     /* ESTALE is not defined on Interix systems */
   case ESTALE:
+#endif
   case ENOSYS:
     /* these should force the client to close the file and reconnect */
     
@@ -22384,13 +23727,12 @@ static void vxworksReleaseFileId(struct vxworksFileId *pId){
 **
 ** If you close a file descriptor that points to a file that has locks,
 ** all locks on that file that are owned by the current process are
-** released.  To work around this problem, each unixFile structure contains
-** a pointer to an unixOpenCnt structure.  There is one unixOpenCnt structure
-** per open inode, which means that multiple unixFile can point to a single
-** unixOpenCnt.  When an attempt is made to close an unixFile, if there are
+** released.  To work around this problem, each unixInodeInfo object
+** maintains a count of the number of pending locks on tha inode.
+** When an attempt is made to close an unixFile, if there are
 ** other unixFile open on the same inode that are holding locks, the call
 ** to close() the file descriptor is deferred until all of the locks clear.
-** The unixOpenCnt structure keeps a list of file descriptors that need to
+** The unixInodeInfo structure keeps a list of file descriptors that need to
 ** be closed and that list is walked (and cleared) when the last lock
 ** clears.
 **
@@ -22405,46 +23747,19 @@ static void vxworksReleaseFileId(struct vxworksFileId *pId){
 ** in thread B.  But there is no way to know at compile-time which
 ** threading library is being used.  So there is no way to know at
 ** compile-time whether or not thread A can override locks on thread B.
-** We have to do a run-time check to discover the behavior of the
+** One has to do a run-time check to discover the behavior of the
 ** current process.
 **
-** On systems where thread A is unable to modify locks created by
-** thread B, we have to keep track of which thread created each
-** lock.  Hence there is an extra field in the key to the unixLockInfo
-** structure to record this information.  And on those systems it
-** is illegal to begin a transaction in one thread and finish it
-** in another.  For this latter restriction, there is no work-around.
-** It is a limitation of LinuxThreads.
+** SQLite used to support LinuxThreads.  But support for LinuxThreads
+** was dropped beginning with version 3.7.0.  SQLite will still work with
+** LinuxThreads provided that (1) there is no more than one connection 
+** per database file in the same process and (2) database connections
+** do not move across threads.
 */
 
-/*
-** Set or check the unixFile.tid field.  This field is set when an unixFile
-** is first opened.  All subsequent uses of the unixFile verify that the
-** same thread is operating on the unixFile.  Some operating systems do
-** not allow locks to be overridden by other threads and that restriction
-** means that sqlite3* database handles cannot be moved from one thread
-** to another while locks are held.
-**
-** Version 3.3.1 (2006-01-15):  unixFile can be moved from one thread to
-** another as long as we are running on a system that supports threads
-** overriding each others locks (which is now the most common behavior)
-** or if no locks are held.  But the unixFile.pLock field needs to be
-** recomputed because its key includes the thread-id.  See the 
-** transferOwnership() function below for additional information
-*/
-#if SQLITE_THREADSAFE && defined(__linux__)
-# define SET_THREADID(X)   (X)->tid = pthread_self()
-# define CHECK_THREADID(X) (threadsOverrideEachOthersLocks==0 && \
-                            !pthread_equal((X)->tid, pthread_self()))
-#else
-# define SET_THREADID(X)
-# define CHECK_THREADID(X) 0
-#endif
-
 /*
 ** An instance of the following structure serves as the key used
-** to locate a particular unixOpenCnt structure given its inode.  This
-** is the same as the unixLockKey except that the thread ID is omitted.
+** to locate a particular unixInodeInfo object.
 */
 struct unixFileId {
   dev_t dev;                  /* Device number */
@@ -22455,23 +23770,6 @@ struct unixFileId {
 #endif
 };
 
-/*
-** An instance of the following structure serves as the key used
-** to locate a particular unixLockInfo structure given its inode.
-**
-** If threads cannot override each others locks (LinuxThreads), then we
-** set the unixLockKey.tid field to the thread ID.  If threads can override
-** each others locks (Posix and NPTL) then tid is always set to zero.
-** tid is omitted if we compile without threading support or on an OS
-** other than linux.
-*/
-struct unixLockKey {
-  struct unixFileId fid;  /* Unique identifier for the file */
-#if SQLITE_THREADSAFE && defined(__linux__)
-  pthread_t tid;  /* Thread ID of lock owner. Zero if not using LinuxThreads */
-#endif
-};
-
 /*
 ** An instance of the following structure is allocated for each open
 ** inode.  Or, on LinuxThreads, there is one of these structures for
@@ -22481,212 +23779,193 @@ struct unixLockKey {
 ** structure contains a pointer to an instance of this object and this
 ** object keeps a count of the number of unixFile pointing to it.
 */
-struct unixLockInfo {
-  struct unixLockKey lockKey;     /* The lookup key */
-  int cnt;                        /* Number of SHARED locks held */
-  int locktype;                   /* One of SHARED_LOCK, RESERVED_LOCK etc. */
+struct unixInodeInfo {
+  struct unixFileId fileId;       /* The lookup key */
+  int nShared;                    /* Number of SHARED locks held */
+  unsigned char eFileLock;        /* One of SHARED_LOCK, RESERVED_LOCK etc. */
+  unsigned char bProcessLock;     /* An exclusive process lock is held */
   int nRef;                       /* Number of pointers to this structure */
-  struct unixLockInfo *pNext;     /* List of all unixLockInfo objects */
-  struct unixLockInfo *pPrev;     /*    .... doubly linked */
-};
-
-/*
-** An instance of the following structure is allocated for each open
-** inode.  This structure keeps track of the number of locks on that
-** inode.  If a close is attempted against an inode that is holding
-** locks, the close is deferred until all locks clear by adding the
-** file descriptor to be closed to the pending list.
-**
-** TODO:  Consider changing this so that there is only a single file
-** descriptor for each open file, even when it is opened multiple times.
-** The close() system call would only occur when the last database
-** using the file closes.
-*/
-struct unixOpenCnt {
-  struct unixFileId fileId;   /* The lookup key */
-  int nRef;                   /* Number of pointers to this structure */
-  int nLock;                  /* Number of outstanding locks */
-  int nPending;               /* Number of pending close() operations */
-  int *aPending;            /* Malloced space holding fd's awaiting a close() */
+  unixShmNode *pShmNode;          /* Shared memory associated with this inode */
+  int nLock;                      /* Number of outstanding file locks */
+  UnixUnusedFd *pUnused;          /* Unused file descriptors to close */
+  unixInodeInfo *pNext;           /* List of all unixInodeInfo objects */
+  unixInodeInfo *pPrev;           /*    .... doubly linked */
+#if SQLITE_ENABLE_LOCKING_STYLE
+  unsigned long long sharedByte;  /* for AFP simulated shared lock */
+#endif
 #if OS_VXWORKS
-  sem_t *pSem;                     /* Named POSIX semaphore */
-  char aSemName[MAX_PATHNAME+1];   /* Name of that semaphore */
+  sem_t *pSem;                    /* Named POSIX semaphore */
+  char aSemName[MAX_PATHNAME+2];  /* Name of that semaphore */
 #endif
-  struct unixOpenCnt *pNext, *pPrev;   /* List of all unixOpenCnt objects */
 };
 
 /*
-** Lists of all unixLockInfo and unixOpenCnt objects.  These used to be hash
-** tables.  But the number of objects is rarely more than a dozen and
-** never exceeds a few thousand.  And lookup is not on a critical
-** path so a simple linked list will suffice.
+** A lists of all unixInodeInfo objects.
 */
-static struct unixLockInfo *lockList = 0;
-static struct unixOpenCnt *openList = 0;
+static unixInodeInfo *inodeList = 0;
 
 /*
-** This variable remembers whether or not threads can override each others
-** locks.
 **
-**    0:  No.  Threads cannot override each others locks.  (LinuxThreads)
-**    1:  Yes.  Threads can override each others locks.  (Posix & NLPT)
-**   -1:  We don't know yet.
+** This function - unixLogError_x(), is only ever called via the macro
+** unixLogError().
 **
-** On some systems, we know at compile-time if threads can override each
-** others locks.  On those systems, the SQLITE_THREAD_OVERRIDE_LOCK macro
-** will be set appropriately.  On other systems, we have to check at
-** runtime.  On these latter systems, SQLTIE_THREAD_OVERRIDE_LOCK is
-** undefined.
+** It is invoked after an error occurs in an OS function and errno has been
+** set. It logs a message using sqlite3_log() containing the current value of
+** errno and, if possible, the human-readable equivalent from strerror() or
+** strerror_r().
 **
-** This variable normally has file scope only.  But during testing, we make
-** it a global so that the test code can change its value in order to verify
-** that the right stuff happens in either case.
+** The first argument passed to the macro should be the error code that
+** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). 
+** The two subsequent arguments should be the name of the OS function that
+** failed (e.g. "unlink", "open") and the associated file-system path,
+** if any.
 */
-#if SQLITE_THREADSAFE && defined(__linux__)
-#  ifndef SQLITE_THREAD_OVERRIDE_LOCK
-#    define SQLITE_THREAD_OVERRIDE_LOCK -1
-#  endif
-#  ifdef SQLITE_TEST
-int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
-#  else
-static int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
-#  endif
+#define unixLogError(a,b,c)     unixLogErrorAtLine(a,b,c,__LINE__)
+static int unixLogErrorAtLine(
+  int errcode,                    /* SQLite error code */
+  const char *zFunc,              /* Name of OS function that failed */
+  const char *zPath,              /* File path associated with error */
+  int iLine                       /* Source line number where error occurred */
+){
+  char *zErr;                     /* Message from strerror() or equivalent */
+  int iErrno = errno;             /* Saved syscall error number */
+
+  /* If this is not a threadsafe build (SQLITE_THREADSAFE==0), then use
+  ** the strerror() function to obtain the human-readable error message
+  ** equivalent to errno. Otherwise, use strerror_r().
+  */ 
+#if SQLITE_THREADSAFE && defined(HAVE_STRERROR_R)
+  char aErr[80];
+  memset(aErr, 0, sizeof(aErr));
+  zErr = aErr;
+
+  /* If STRERROR_R_CHAR_P (set by autoconf scripts) or __USE_GNU is defined,
+  ** assume that the system provides the GNU version of strerror_r() that
+  ** returns a pointer to a buffer containing the error message. That pointer 
+  ** may point to aErr[], or it may point to some static storage somewhere. 
+  ** Otherwise, assume that the system provides the POSIX version of 
+  ** strerror_r(), which always writes an error message into aErr[].
+  **
+  ** If the code incorrectly assumes that it is the POSIX version that is
+  ** available, the error message will often be an empty string. Not a
+  ** huge problem. Incorrectly concluding that the GNU version is available 
+  ** could lead to a segfault though.
+  */
+#if defined(STRERROR_R_CHAR_P) || defined(__USE_GNU)
+  zErr = 
+# endif
+  strerror_r(iErrno, aErr, sizeof(aErr)-1);
+
+#elif SQLITE_THREADSAFE
+  /* This is a threadsafe build, but strerror_r() is not available. */
+  zErr = "";
+#else
+  /* Non-threadsafe build, use strerror(). */
+  zErr = strerror(iErrno);
 #endif
 
-/*
-** This structure holds information passed into individual test
-** threads by the testThreadLockingBehavior() routine.
-*/
-struct threadTestData {
-  int fd;                /* File to be locked */
-  struct flock lock;     /* The locking operation */
-  int result;            /* Result of the locking operation */
-};
+  assert( errcode!=SQLITE_OK );
+  if( zPath==0 ) zPath = "";
+  sqlite3_log(errcode,
+      "os_unix.c:%d: (%d) %s(%s) - %s",
+      iLine, iErrno, zFunc, zPath, zErr
+  );
+
+  return errcode;
+}
 
-#if SQLITE_THREADSAFE && defined(__linux__)
 /*
-** This function is used as the main routine for a thread launched by
-** testThreadLockingBehavior(). It tests whether the shared-lock obtained
-** by the main thread in testThreadLockingBehavior() conflicts with a
-** hypothetical write-lock obtained by this thread on the same file.
+** Close a file descriptor.
 **
-** The write-lock is not actually acquired, as this is not possible if 
-** the file is open in read-only mode (see ticket #3472).
+** We assume that close() almost always works, since it is only in a
+** very sick application or on a very sick platform that it might fail.
+** If it does fail, simply leak the file descriptor, but do log the
+** error.
+**
+** Note that it is not safe to retry close() after EINTR since the
+** file descriptor might have already been reused by another thread.
+** So we don't even try to recover from an EINTR.  Just log the error
+** and move on.
+*/
+static void robust_close(unixFile *pFile, int h, int lineno){
+  if( osClose(h) ){
+    unixLogErrorAtLine(SQLITE_IOERR_CLOSE, "close",
+                       pFile ? pFile->zPath : 0, lineno);
+  }
+}
+
+/*
+** Close all file descriptors accumuated in the unixInodeInfo->pUnused list.
 */ 
-static void *threadLockingTest(void *pArg){
-  struct threadTestData *pData = (struct threadTestData*)pArg;
-  pData->result = fcntl(pData->fd, F_GETLK, &pData->lock);
-  return pArg;
+static void closePendingFds(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  UnixUnusedFd *p;
+  UnixUnusedFd *pNext;
+  for(p=pInode->pUnused; p; p=pNext){
+    pNext = p->pNext;
+    robust_close(pFile, p->fd, __LINE__);
+    sqlite3_free(p);
+  }
+  pInode->pUnused = 0;
 }
-#endif /* SQLITE_THREADSAFE && defined(__linux__) */
-
-
-#if SQLITE_THREADSAFE && defined(__linux__)
-/*
-** This procedure attempts to determine whether or not threads
-** can override each others locks then sets the 
-** threadsOverrideEachOthersLocks variable appropriately.
-*/
-static void testThreadLockingBehavior(int fd_orig){
-  int fd;
-  int rc;
-  struct threadTestData d;
-  struct flock l;
-  pthread_t t;
-
-  fd = dup(fd_orig);
-  if( fd<0 ) return;
-  memset(&l, 0, sizeof(l));
-  l.l_type = F_RDLCK;
-  l.l_len = 1;
-  l.l_start = 0;
-  l.l_whence = SEEK_SET;
-  rc = fcntl(fd_orig, F_SETLK, &l);
-  if( rc!=0 ) return;
-  memset(&d, 0, sizeof(d));
-  d.fd = fd;
-  d.lock = l;
-  d.lock.l_type = F_WRLCK;
-  pthread_create(&t, 0, threadLockingTest, &d);
-  pthread_join(t, 0);
-  close(fd);
-  if( d.result!=0 ) return;
-  threadsOverrideEachOthersLocks = (d.lock.l_type==F_UNLCK);
-}
-#endif /* SQLITE_THERADSAFE && defined(__linux__) */
 
 /*
-** Release a unixLockInfo structure previously allocated by findLockInfo().
+** Release a unixInodeInfo structure previously allocated by findInodeInfo().
+**
+** The mutex entered using the unixEnterMutex() function must be held
+** when this function is called.
 */
-static void releaseLockInfo(struct unixLockInfo *pLock){
-  if( pLock ){
-    pLock->nRef--;
-    if( pLock->nRef==0 ){
-      if( pLock->pPrev ){
-        assert( pLock->pPrev->pNext==pLock );
-        pLock->pPrev->pNext = pLock->pNext;
+static void releaseInodeInfo(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  assert( unixMutexHeld() );
+  if( ALWAYS(pInode) ){
+    pInode->nRef--;
+    if( pInode->nRef==0 ){
+      assert( pInode->pShmNode==0 );
+      closePendingFds(pFile);
+      if( pInode->pPrev ){
+        assert( pInode->pPrev->pNext==pInode );
+        pInode->pPrev->pNext = pInode->pNext;
       }else{
-        assert( lockList==pLock );
-        lockList = pLock->pNext;
+        assert( inodeList==pInode );
+        inodeList = pInode->pNext;
       }
-      if( pLock->pNext ){
-        assert( pLock->pNext->pPrev==pLock );
-        pLock->pNext->pPrev = pLock->pPrev;
+      if( pInode->pNext ){
+        assert( pInode->pNext->pPrev==pInode );
+        pInode->pNext->pPrev = pInode->pPrev;
       }
-      sqlite3_free(pLock);
+      sqlite3_free(pInode);
     }
   }
 }
 
 /*
-** Release a unixOpenCnt structure previously allocated by findLockInfo().
-*/
-static void releaseOpenCnt(struct unixOpenCnt *pOpen){
-  if( pOpen ){
-    pOpen->nRef--;
-    if( pOpen->nRef==0 ){
-      if( pOpen->pPrev ){
-        assert( pOpen->pPrev->pNext==pOpen );
-        pOpen->pPrev->pNext = pOpen->pNext;
-      }else{
-        assert( openList==pOpen );
-        openList = pOpen->pNext;
-      }
-      if( pOpen->pNext ){
-        assert( pOpen->pNext->pPrev==pOpen );
-        pOpen->pNext->pPrev = pOpen->pPrev;
-      }
-      sqlite3_free(pOpen->aPending);
-      sqlite3_free(pOpen);
-    }
-  }
-}
-
-/*
-** Given a file descriptor, locate unixLockInfo and unixOpenCnt structures that
-** describes that file descriptor.  Create new ones if necessary.  The
-** return values might be uninitialized if an error occurs.
+** Given a file descriptor, locate the unixInodeInfo object that
+** describes that file descriptor.  Create a new one if necessary.  The
+** return value might be uninitialized if an error occurs.
+**
+** The mutex entered using the unixEnterMutex() function must be held
+** when this function is called.
 **
 ** Return an appropriate error code.
 */
-static int findLockInfo(
+static int findInodeInfo(
   unixFile *pFile,               /* Unix file with file desc used in the key */
-  struct unixLockInfo **ppLock,  /* Return the unixLockInfo structure here */
-  struct unixOpenCnt **ppOpen    /* Return the unixOpenCnt structure here */
+  unixInodeInfo **ppInode        /* Return the unixInodeInfo object here */
 ){
   int rc;                        /* System call return code */
   int fd;                        /* The file descriptor for pFile */
-  struct unixLockKey lockKey;    /* Lookup key for the unixLockInfo structure */
-  struct unixFileId fileId;      /* Lookup key for the unixOpenCnt struct */
+  struct unixFileId fileId;      /* Lookup key for the unixInodeInfo */
   struct stat statbuf;           /* Low-level file information */
-  struct unixLockInfo *pLock;    /* Candidate unixLockInfo object */
-  struct unixOpenCnt *pOpen;     /* Candidate unixOpenCnt object */
+  unixInodeInfo *pInode = 0;     /* Candidate unixInodeInfo object */
+
+  assert( unixMutexHeld() );
 
   /* Get low-level information about the file that we can used to
   ** create a unique name for the file.
   */
   fd = pFile->h;
-  rc = fstat(fd, &statbuf);
+  rc = osFstat(fd, &statbuf);
   if( rc!=0 ){
     pFile->lastErrno = errno;
 #ifdef EOVERFLOW
@@ -22695,6 +23974,7 @@ static int findLockInfo(
     return SQLITE_IOERR;
   }
 
+#ifdef __APPLE__
   /* On OS X on an msdos filesystem, the inode number is reported
   ** incorrectly for zero-size files.  See ticket #3260.  To work
   ** around this problem (we consider it a bug in OS X, not SQLite)
@@ -22705,136 +23985,50 @@ static int findLockInfo(
   ** is a race condition such that another thread has already populated
   ** the first page of the database, no damage is done.
   */
-  if( statbuf.st_size==0 ){
-    write(fd, "S", 1);
-    rc = fstat(fd, &statbuf);
+  if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){
+    do{ rc = osWrite(fd, "S", 1); }while( rc<0 && errno==EINTR );
+    if( rc!=1 ){
+      pFile->lastErrno = errno;
+      return SQLITE_IOERR;
+    }
+    rc = osFstat(fd, &statbuf);
     if( rc!=0 ){
       pFile->lastErrno = errno;
       return SQLITE_IOERR;
     }
   }
+#endif
 
-  memset(&lockKey, 0, sizeof(lockKey));
-  lockKey.fid.dev = statbuf.st_dev;
+  memset(&fileId, 0, sizeof(fileId));
+  fileId.dev = statbuf.st_dev;
 #if OS_VXWORKS
-  lockKey.fid.pId = pFile->pId;
+  fileId.pId = pFile->pId;
 #else
-  lockKey.fid.ino = statbuf.st_ino;
+  fileId.ino = statbuf.st_ino;
 #endif
-#if SQLITE_THREADSAFE && defined(__linux__)
-  if( threadsOverrideEachOthersLocks<0 ){
-    testThreadLockingBehavior(fd);
+  pInode = inodeList;
+  while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
+    pInode = pInode->pNext;
   }
-  lockKey.tid = threadsOverrideEachOthersLocks ? 0 : pthread_self();
-#endif
-  fileId = lockKey.fid;
-  if( ppLock!=0 ){
-    pLock = lockList;
-    while( pLock && memcmp(&lockKey, &pLock->lockKey, sizeof(lockKey)) ){
-      pLock = pLock->pNext;
+  if( pInode==0 ){
+    pInode = sqlite3_malloc( sizeof(*pInode) );
+    if( pInode==0 ){
+      return SQLITE_NOMEM;
     }
-    if( pLock==0 ){
-      pLock = sqlite3_malloc( sizeof(*pLock) );
-      if( pLock==0 ){
-        rc = SQLITE_NOMEM;
-        goto exit_findlockinfo;
-      }
-      pLock->lockKey = lockKey;
-      pLock->nRef = 1;
-      pLock->cnt = 0;
-      pLock->locktype = 0;
-      pLock->pNext = lockList;
-      pLock->pPrev = 0;
-      if( lockList ) lockList->pPrev = pLock;
-      lockList = pLock;
-    }else{
-      pLock->nRef++;
-    }
-    *ppLock = pLock;
+    memset(pInode, 0, sizeof(*pInode));
+    memcpy(&pInode->fileId, &fileId, sizeof(fileId));
+    pInode->nRef = 1;
+    pInode->pNext = inodeList;
+    pInode->pPrev = 0;
+    if( inodeList ) inodeList->pPrev = pInode;
+    inodeList = pInode;
+  }else{
+    pInode->nRef++;
   }
-  if( ppOpen!=0 ){
-    pOpen = openList;
-    while( pOpen && memcmp(&fileId, &pOpen->fileId, sizeof(fileId)) ){
-      pOpen = pOpen->pNext;
-    }
-    if( pOpen==0 ){
-      pOpen = sqlite3_malloc( sizeof(*pOpen) );
-      if( pOpen==0 ){
-        releaseLockInfo(pLock);
-        rc = SQLITE_NOMEM;
-        goto exit_findlockinfo;
-      }
-      pOpen->fileId = fileId;
-      pOpen->nRef = 1;
-      pOpen->nLock = 0;
-      pOpen->nPending = 0;
-      pOpen->aPending = 0;
-      pOpen->pNext = openList;
-      pOpen->pPrev = 0;
-      if( openList ) openList->pPrev = pOpen;
-      openList = pOpen;
-#if OS_VXWORKS
-      pOpen->pSem = NULL;
-      pOpen->aSemName[0] = '\0';
-#endif
-    }else{
-      pOpen->nRef++;
-    }
-    *ppOpen = pOpen;
-  }
-
-exit_findlockinfo:
-  return rc;
+  *ppInode = pInode;
+  return SQLITE_OK;
 }
 
-/*
-** If we are currently in a different thread than the thread that the
-** unixFile argument belongs to, then transfer ownership of the unixFile
-** over to the current thread.
-**
-** A unixFile is only owned by a thread on systems that use LinuxThreads.
-**
-** Ownership transfer is only allowed if the unixFile is currently unlocked.
-** If the unixFile is locked and an ownership is wrong, then return
-** SQLITE_MISUSE.  SQLITE_OK is returned if everything works.
-*/
-#if SQLITE_THREADSAFE && defined(__linux__)
-static int transferOwnership(unixFile *pFile){
-  int rc;
-  pthread_t hSelf;
-  if( threadsOverrideEachOthersLocks ){
-    /* Ownership transfers not needed on this system */
-    return SQLITE_OK;
-  }
-  hSelf = pthread_self();
-  if( pthread_equal(pFile->tid, hSelf) ){
-    /* We are still in the same thread */
-    OSTRACE1("No-transfer, same thread\n");
-    return SQLITE_OK;
-  }
-  if( pFile->locktype!=NO_LOCK ){
-    /* We cannot change ownership while we are holding a lock! */
-    return SQLITE_MISUSE;
-  }
-  OSTRACE4("Transfer ownership of %d from %d to %d\n",
-            pFile->h, pFile->tid, hSelf);
-  pFile->tid = hSelf;
-  if (pFile->pLock != NULL) {
-    releaseLockInfo(pFile->pLock);
-    rc = findLockInfo(pFile, &pFile->pLock, 0);
-    OSTRACE5("LOCK    %d is now %s(%s,%d)\n", pFile->h,
-           locktypeName(pFile->locktype),
-           locktypeName(pFile->pLock->locktype), pFile->pLock->cnt);
-    return rc;
-  } else {
-    return SQLITE_OK;
-  }
-}
-#else  /* if not SQLITE_THREADSAFE */
-  /* On single-threaded builds, ownership transfer is a no-op */
-# define transferOwnership(X) SQLITE_OK
-#endif /* SQLITE_THREADSAFE */
-
 
 /*
 ** This routine checks if there is a RESERVED lock held on the specified
@@ -22850,39 +24044,87 @@ static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
   SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
 
   assert( pFile );
-  unixEnterMutex(); /* Because pFile->pLock is shared across threads */
+  unixEnterMutex(); /* Because pFile->pInode is shared across threads */
 
   /* Check if a thread in this process holds such a lock */
-  if( pFile->pLock->locktype>SHARED_LOCK ){
+  if( pFile->pInode->eFileLock>SHARED_LOCK ){
     reserved = 1;
   }
 
   /* Otherwise see if some other process holds it.
   */
-  if( !reserved ){
+#ifndef __DJGPP__
+  if( !reserved && !pFile->pInode->bProcessLock ){
     struct flock lock;
     lock.l_whence = SEEK_SET;
     lock.l_start = RESERVED_BYTE;
     lock.l_len = 1;
     lock.l_type = F_WRLCK;
-    if (-1 == fcntl(pFile->h, F_GETLK, &lock)) {
-      int tErrno = errno;
-      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
-      pFile->lastErrno = tErrno;
+    if( osFcntl(pFile->h, F_GETLK, &lock) ){
+      rc = SQLITE_IOERR_CHECKRESERVEDLOCK;
+      pFile->lastErrno = errno;
     } else if( lock.l_type!=F_UNLCK ){
       reserved = 1;
     }
   }
+#endif
   
   unixLeaveMutex();
-  OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
+  OSTRACE(("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved));
 
   *pResOut = reserved;
   return rc;
 }
 
 /*
-** Lock the file with the lock specified by parameter locktype - one
+** Attempt to set a system-lock on the file pFile.  The lock is 
+** described by pLock.
+**
+** If the pFile was opened read/write from unix-excl, then the only lock
+** ever obtained is an exclusive lock, and it is obtained exactly once
+** the first time any lock is attempted.  All subsequent system locking
+** operations become no-ops.  Locking operations still happen internally,
+** in order to coordinate access between separate database connections
+** within this process, but all of that is handled in memory and the
+** operating system does not participate.
+**
+** This function is a pass-through to fcntl(F_SETLK) if pFile is using
+** any VFS other than "unix-excl" or if pFile is opened on "unix-excl"
+** and is read-only.
+**
+** Zero is returned if the call completes successfully, or -1 if a call
+** to fcntl() fails. In this case, errno is set appropriately (by fcntl()).
+*/
+static int unixFileLock(unixFile *pFile, struct flock *pLock){
+  int rc;
+  unixInodeInfo *pInode = pFile->pInode;
+  assert( unixMutexHeld() );
+  assert( pInode!=0 );
+  if( ((pFile->ctrlFlags & UNIXFILE_EXCL)!=0 || pInode->bProcessLock)
+   && ((pFile->ctrlFlags & UNIXFILE_RDONLY)==0)
+  ){
+    if( pInode->bProcessLock==0 ){
+      struct flock lock;
+      assert( pInode->nLock==0 );
+      lock.l_whence = SEEK_SET;
+      lock.l_start = SHARED_FIRST;
+      lock.l_len = SHARED_SIZE;
+      lock.l_type = F_WRLCK;
+      rc = osFcntl(pFile->h, F_SETLK, &lock);
+      if( rc<0 ) return rc;
+      pInode->bProcessLock = 1;
+      pInode->nLock++;
+    }else{
+      rc = 0;
+    }
+  }else{
+    rc = osFcntl(pFile->h, F_SETLK, pLock);
+  }
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
 ** of the following:
 **
 **     (1) SHARED_LOCK
@@ -22905,7 +24147,7 @@ static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
 ** This routine will only increase a lock.  Use the sqlite3OsUnlock()
 ** routine to lower a locking level.
 */
-static int unixLock(sqlite3_file *id, int locktype){
+static int unixLock(sqlite3_file *id, int eFileLock){
   /* The following describes the implementation of the various locks and
   ** lock transitions in terms of the POSIX advisory shared and exclusive
   ** lock primitives (called read-locks and write-locks below, to avoid
@@ -22946,49 +24188,44 @@ static int unixLock(sqlite3_file *id, int locktype){
   */
   int rc = SQLITE_OK;
   unixFile *pFile = (unixFile*)id;
-  struct unixLockInfo *pLock = pFile->pLock;
+  unixInodeInfo *pInode;
   struct flock lock;
-  int s;
+  int tErrno = 0;
 
   assert( pFile );
-  OSTRACE7("LOCK    %d %s was %s(%s,%d) pid=%d\n", pFile->h,
-      locktypeName(locktype), locktypeName(pFile->locktype),
-      locktypeName(pLock->locktype), pLock->cnt , getpid());
+  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h,
+      azFileLock(eFileLock), azFileLock(pFile->eFileLock),
+      azFileLock(pFile->pInode->eFileLock), pFile->pInode->nShared , getpid()));
 
   /* If there is already a lock of this type or more restrictive on the
   ** unixFile, do nothing. Don't use the end_lock: exit path, as
   ** unixEnterMutex() hasn't been called yet.
   */
-  if( pFile->locktype>=locktype ){
-    OSTRACE3("LOCK    %d %s ok (already held)\n", pFile->h,
-            locktypeName(locktype));
+  if( pFile->eFileLock>=eFileLock ){
+    OSTRACE(("LOCK    %d %s ok (already held) (unix)\n", pFile->h,
+            azFileLock(eFileLock)));
     return SQLITE_OK;
   }
 
-  /* Make sure the locking sequence is correct
+  /* Make sure the locking sequence is correct.
+  **  (1) We never move from unlocked to anything higher than shared lock.
+  **  (2) SQLite never explicitly requests a pendig lock.
+  **  (3) A shared lock is always held when a reserve lock is requested.
   */
-  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
-  assert( locktype!=PENDING_LOCK );
-  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
+  assert( eFileLock!=PENDING_LOCK );
+  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );
 
-  /* This mutex is needed because pFile->pLock is shared across threads
+  /* This mutex is needed because pFile->pInode is shared across threads
   */
   unixEnterMutex();
-
-  /* Make sure the current thread owns the pFile.
-  */
-  rc = transferOwnership(pFile);
-  if( rc!=SQLITE_OK ){
-    unixLeaveMutex();
-    return rc;
-  }
-  pLock = pFile->pLock;
+  pInode = pFile->pInode;
 
   /* If some thread using this PID has a lock via a different unixFile*
   ** handle that precludes the requested lock, return BUSY.
   */
-  if( (pFile->locktype!=pLock->locktype && 
-          (pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
+  if( (pFile->eFileLock!=pInode->eFileLock && 
+          (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
   ){
     rc = SQLITE_BUSY;
     goto end_lock;
@@ -22998,35 +24235,33 @@ static int unixLock(sqlite3_file *id, int locktype){
   ** has a SHARED or RESERVED lock, then increment reference counts and
   ** return SQLITE_OK.
   */
-  if( locktype==SHARED_LOCK && 
-      (pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
-    assert( locktype==SHARED_LOCK );
-    assert( pFile->locktype==0 );
-    assert( pLock->cnt>0 );
-    pFile->locktype = SHARED_LOCK;
-    pLock->cnt++;
-    pFile->pOpen->nLock++;
+  if( eFileLock==SHARED_LOCK && 
+      (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
+    assert( eFileLock==SHARED_LOCK );
+    assert( pFile->eFileLock==0 );
+    assert( pInode->nShared>0 );
+    pFile->eFileLock = SHARED_LOCK;
+    pInode->nShared++;
+    pInode->nLock++;
     goto end_lock;
   }
 
-  lock.l_len = 1L;
-
-  lock.l_whence = SEEK_SET;
 
   /* A PENDING lock is needed before acquiring a SHARED lock and before
   ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
   ** be released.
   */
-  if( locktype==SHARED_LOCK 
-      || (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
+  lock.l_len = 1L;
+  lock.l_whence = SEEK_SET;
+  if( eFileLock==SHARED_LOCK 
+      || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK)
   ){
-    lock.l_type = (locktype==SHARED_LOCK?F_RDLCK:F_WRLCK);
+    lock.l_type = (eFileLock==SHARED_LOCK?F_RDLCK:F_WRLCK);
     lock.l_start = PENDING_BYTE;
-    s = fcntl(pFile->h, F_SETLK, &lock);
-    if( s==(-1) ){
-      int tErrno = errno;
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
       rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
-      if( IS_LOCK_ERROR(rc) ){
+      if( rc!=SQLITE_BUSY ){
         pFile->lastErrno = tErrno;
       }
       goto end_lock;
@@ -23037,43 +24272,40 @@ static int unixLock(sqlite3_file *id, int locktype){
   /* If control gets to this point, then actually go ahead and make
   ** operating system calls for the specified lock.
   */
-  if( locktype==SHARED_LOCK ){
-    int tErrno = 0;
-    assert( pLock->cnt==0 );
-    assert( pLock->locktype==0 );
+  if( eFileLock==SHARED_LOCK ){
+    assert( pInode->nShared==0 );
+    assert( pInode->eFileLock==0 );
+    assert( rc==SQLITE_OK );
 
     /* Now get the read-lock */
     lock.l_start = SHARED_FIRST;
     lock.l_len = SHARED_SIZE;
-    if( (s = fcntl(pFile->h, F_SETLK, &lock))==(-1) ){
+    if( unixFileLock(pFile, &lock) ){
       tErrno = errno;
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
     }
+
     /* Drop the temporary PENDING lock */
     lock.l_start = PENDING_BYTE;
     lock.l_len = 1L;
     lock.l_type = F_UNLCK;
-    if( fcntl(pFile->h, F_SETLK, &lock)!=0 ){
-      if( s != -1 ){
-        /* This could happen with a network mount */
-        tErrno = errno; 
-        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK); 
-        if( IS_LOCK_ERROR(rc) ){
-          pFile->lastErrno = tErrno;
-        }
-        goto end_lock;
-      }
+    if( unixFileLock(pFile, &lock) && rc==SQLITE_OK ){
+      /* This could happen with a network mount */
+      tErrno = errno;
+      rc = SQLITE_IOERR_UNLOCK; 
     }
-    if( s==(-1) ){
-      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
-      if( IS_LOCK_ERROR(rc) ){
+
+    if( rc ){
+      if( rc!=SQLITE_BUSY ){
         pFile->lastErrno = tErrno;
       }
+      goto end_lock;
     }else{
-      pFile->locktype = SHARED_LOCK;
-      pFile->pOpen->nLock++;
-      pLock->cnt = 1;
+      pFile->eFileLock = SHARED_LOCK;
+      pInode->nLock++;
+      pInode->nShared = 1;
     }
-  }else if( locktype==EXCLUSIVE_LOCK && pLock->cnt>1 ){
+  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
     /* We are trying for an exclusive lock but another thread in this
     ** same process is still holding a shared lock. */
     rc = SQLITE_BUSY;
@@ -23082,39 +24314,37 @@ static int unixLock(sqlite3_file *id, int locktype){
     ** assumed that there is a SHARED or greater lock on the file
     ** already.
     */
-    assert( 0!=pFile->locktype );
+    assert( 0!=pFile->eFileLock );
     lock.l_type = F_WRLCK;
-    switch( locktype ){
-      case RESERVED_LOCK:
-        lock.l_start = RESERVED_BYTE;
-        break;
-      case EXCLUSIVE_LOCK:
-        lock.l_start = SHARED_FIRST;
-        lock.l_len = SHARED_SIZE;
-        break;
-      default:
-        assert(0);
+
+    assert( eFileLock==RESERVED_LOCK || eFileLock==EXCLUSIVE_LOCK );
+    if( eFileLock==RESERVED_LOCK ){
+      lock.l_start = RESERVED_BYTE;
+      lock.l_len = 1L;
+    }else{
+      lock.l_start = SHARED_FIRST;
+      lock.l_len = SHARED_SIZE;
     }
-    s = fcntl(pFile->h, F_SETLK, &lock);
-    if( s==(-1) ){
-      int tErrno = errno;
+
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
       rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
-      if( IS_LOCK_ERROR(rc) ){
+      if( rc!=SQLITE_BUSY ){
         pFile->lastErrno = tErrno;
       }
     }
   }
   
 
-#ifndef NDEBUG
+#ifdef SQLITE_DEBUG
   /* Set up the transaction-counter change checking flags when
   ** transitioning from a SHARED to a RESERVED lock.  The change
   ** from SHARED to RESERVED marks the beginning of a normal
   ** write operation (not a hot journal rollback).
   */
   if( rc==SQLITE_OK
-   && pFile->locktype<=SHARED_LOCK
-   && locktype==RESERVED_LOCK
+   && pFile->eFileLock<=SHARED_LOCK
+   && eFileLock==RESERVED_LOCK
   ){
     pFile->transCntrChng = 0;
     pFile->dbUpdate = 0;
@@ -23124,56 +24354,68 @@ static int unixLock(sqlite3_file *id, int locktype){
 
 
   if( rc==SQLITE_OK ){
-    pFile->locktype = locktype;
-    pLock->locktype = locktype;
-  }else if( locktype==EXCLUSIVE_LOCK ){
-    pFile->locktype = PENDING_LOCK;
-    pLock->locktype = PENDING_LOCK;
+    pFile->eFileLock = eFileLock;
+    pInode->eFileLock = eFileLock;
+  }else if( eFileLock==EXCLUSIVE_LOCK ){
+    pFile->eFileLock = PENDING_LOCK;
+    pInode->eFileLock = PENDING_LOCK;
   }
 
 end_lock:
   unixLeaveMutex();
-  OSTRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
-      rc==SQLITE_OK ? "ok" : "failed");
+  OSTRACE(("LOCK    %d %s %s (unix)\n", pFile->h, azFileLock(eFileLock), 
+      rc==SQLITE_OK ? "ok" : "failed"));
   return rc;
 }
 
 /*
-** Lower the locking level on file descriptor pFile to locktype.  locktype
+** Add the file descriptor used by file handle pFile to the corresponding
+** pUnused list.
+*/
+static void setPendingFd(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  UnixUnusedFd *p = pFile->pUnused;
+  p->pNext = pInode->pUnused;
+  pInode->pUnused = p;
+  pFile->h = -1;
+  pFile->pUnused = 0;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
+** 
+** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED
+** the byte range is divided into 2 parts and the first part is unlocked then
+** set to a read lock, then the other part is simply unlocked.  This works 
+** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to 
+** remove the write lock on a region when a read lock is set.
 */
-static int unixUnlock(sqlite3_file *id, int locktype){
-  struct unixLockInfo *pLock;
+static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode;
   struct flock lock;
   int rc = SQLITE_OK;
-  unixFile *pFile = (unixFile*)id;
-  int h;
 
   assert( pFile );
-  OSTRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d\n", pFile->h, locktype,
-      pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());
+  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, eFileLock,
+      pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
+      getpid()));
 
-  assert( locktype<=SHARED_LOCK );
-  if( pFile->locktype<=locktype ){
+  assert( eFileLock<=SHARED_LOCK );
+  if( pFile->eFileLock<=eFileLock ){
     return SQLITE_OK;
   }
-  if( CHECK_THREADID(pFile) ){
-    return SQLITE_MISUSE;
-  }
   unixEnterMutex();
-  h = pFile->h;
-  pLock = pFile->pLock;
-  assert( pLock->cnt!=0 );
-  if( pFile->locktype>SHARED_LOCK ){
-    assert( pLock->locktype==pFile->locktype );
-    SimulateIOErrorBenign(1);
-    SimulateIOError( h=(-1) )
-    SimulateIOErrorBenign(0);
+  pInode = pFile->pInode;
+  assert( pInode->nShared!=0 );
+  if( pFile->eFileLock>SHARED_LOCK ){
+    assert( pInode->eFileLock==pFile->eFileLock );
 
-#ifndef NDEBUG
+#ifdef SQLITE_DEBUG
     /* When reducing a lock such that other processes can start
     ** reading the database file again, make sure that the
     ** transaction counter was updated if any part of the database
@@ -23182,67 +24424,114 @@ static int unixUnlock(sqlite3_file *id, int locktype){
     ** the file has changed and hence might not know to flush their
     ** cache.  The use of a stale cache can lead to database corruption.
     */
-    assert( pFile->inNormalWrite==0
-         || pFile->dbUpdate==0
-         || pFile->transCntrChng==1 );
     pFile->inNormalWrite = 0;
 #endif
 
+    /* downgrading to a shared lock on NFS involves clearing the write lock
+    ** before establishing the readlock - to avoid a race condition we downgrade
+    ** the lock in 2 blocks, so that part of the range will be covered by a 
+    ** write lock until the rest is covered by a read lock:
+    **  1:   [WWWWW]
+    **  2:   [....W]
+    **  3:   [RRRRW]
+    **  4:   [RRRR.]
+    */
+    if( eFileLock==SHARED_LOCK ){
 
-    if( locktype==SHARED_LOCK ){
-      lock.l_type = F_RDLCK;
-      lock.l_whence = SEEK_SET;
-      lock.l_start = SHARED_FIRST;
-      lock.l_len = SHARED_SIZE;
-      if( fcntl(h, F_SETLK, &lock)==(-1) ){
-        int tErrno = errno;
-        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
-        if( IS_LOCK_ERROR(rc) ){
-          pFile->lastErrno = tErrno;
+#if !defined(__APPLE__) || !SQLITE_ENABLE_LOCKING_STYLE
+      (void)handleNFSUnlock;
+      assert( handleNFSUnlock==0 );
+#endif
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+      if( handleNFSUnlock ){
+        int tErrno;               /* Error code from system call errors */
+        off_t divSize = SHARED_SIZE - 1;
+        
+        lock.l_type = F_UNLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = SQLITE_IOERR_UNLOCK;
+          if( IS_LOCK_ERROR(rc) ){
+            pFile->lastErrno = tErrno;
+          }
+          goto end_unlock;
+        }
+        lock.l_type = F_RDLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
+          if( IS_LOCK_ERROR(rc) ){
+            pFile->lastErrno = tErrno;
+          }
+          goto end_unlock;
+        }
+        lock.l_type = F_UNLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST+divSize;
+        lock.l_len = SHARED_SIZE-divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = SQLITE_IOERR_UNLOCK;
+          if( IS_LOCK_ERROR(rc) ){
+            pFile->lastErrno = tErrno;
+          }
+          goto end_unlock;
+        }
+      }else
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+      {
+        lock.l_type = F_RDLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = SHARED_SIZE;
+        if( unixFileLock(pFile, &lock) ){
+          /* In theory, the call to unixFileLock() cannot fail because another
+          ** process is holding an incompatible lock. If it does, this 
+          ** indicates that the other process is not following the locking
+          ** protocol. If this happens, return SQLITE_IOERR_RDLOCK. Returning
+          ** SQLITE_BUSY would confuse the upper layer (in practice it causes 
+          ** an assert to fail). */ 
+          rc = SQLITE_IOERR_RDLOCK;
+          pFile->lastErrno = errno;
+          goto end_unlock;
         }
-				goto end_unlock;
       }
     }
     lock.l_type = F_UNLCK;
     lock.l_whence = SEEK_SET;
     lock.l_start = PENDING_BYTE;
     lock.l_len = 2L;  assert( PENDING_BYTE+1==RESERVED_BYTE );
-    if( fcntl(h, F_SETLK, &lock)!=(-1) ){
-      pLock->locktype = SHARED_LOCK;
+    if( unixFileLock(pFile, &lock)==0 ){
+      pInode->eFileLock = SHARED_LOCK;
     }else{
-      int tErrno = errno;
-      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
-      if( IS_LOCK_ERROR(rc) ){
-        pFile->lastErrno = tErrno;
-      }
-			goto end_unlock;
+      rc = SQLITE_IOERR_UNLOCK;
+      pFile->lastErrno = errno;
+      goto end_unlock;
     }
   }
-  if( locktype==NO_LOCK ){
-    struct unixOpenCnt *pOpen;
-
+  if( eFileLock==NO_LOCK ){
     /* Decrement the shared lock counter.  Release the lock using an
     ** OS call only when all threads in this same process have released
     ** the lock.
     */
-    pLock->cnt--;
-    if( pLock->cnt==0 ){
+    pInode->nShared--;
+    if( pInode->nShared==0 ){
       lock.l_type = F_UNLCK;
       lock.l_whence = SEEK_SET;
       lock.l_start = lock.l_len = 0L;
-      SimulateIOErrorBenign(1);
-      SimulateIOError( h=(-1) )
-      SimulateIOErrorBenign(0);
-      if( fcntl(h, F_SETLK, &lock)!=(-1) ){
-        pLock->locktype = NO_LOCK;
+      if( unixFileLock(pFile, &lock)==0 ){
+        pInode->eFileLock = NO_LOCK;
       }else{
-        int tErrno = errno;
-        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
-        if( IS_LOCK_ERROR(rc) ){
-          pFile->lastErrno = tErrno;
-        }
-        pLock->cnt = 1;
-				goto end_unlock;
+        rc = SQLITE_IOERR_UNLOCK;
+        pFile->lastErrno = errno;
+        pInode->eFileLock = NO_LOCK;
+        pFile->eFileLock = NO_LOCK;
       }
     }
 
@@ -23250,39 +24539,30 @@ static int unixUnlock(sqlite3_file *id, int locktype){
     ** count reaches zero, close any other file descriptors whose close
     ** was deferred because of outstanding locks.
     */
-    if( rc==SQLITE_OK ){
-      pOpen = pFile->pOpen;
-      pOpen->nLock--;
-      assert( pOpen->nLock>=0 );
-      if( pOpen->nLock==0 && pOpen->nPending>0 ){
-        int i;
-        for(i=0; i<pOpen->nPending; i++){
-          /* close pending fds, but if closing fails don't free the array
-          ** assign -1 to the successfully closed descriptors and record the
-          ** error.  The next attempt to unlock will try again. */
-          if( pOpen->aPending[i] < 0 ) continue;
-          if( close(pOpen->aPending[i]) ){
-            pFile->lastErrno = errno;
-            rc = SQLITE_IOERR_CLOSE;
-          }else{
-            pOpen->aPending[i] = -1;
-          }
-        }
-        if( rc==SQLITE_OK ){
-          sqlite3_free(pOpen->aPending);
-          pOpen->nPending = 0;
-          pOpen->aPending = 0;
-        }
-      }
+    pInode->nLock--;
+    assert( pInode->nLock>=0 );
+    if( pInode->nLock==0 ){
+      closePendingFds(pFile);
     }
   }
-	
+
 end_unlock:
   unixLeaveMutex();
-  if( rc==SQLITE_OK ) pFile->locktype = locktype;
+  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;
   return rc;
 }
 
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int unixUnlock(sqlite3_file *id, int eFileLock){
+  return posixUnlock(id, eFileLock, 0);
+}
+
 /*
 ** This function performs the parts of the "close file" operation 
 ** common to all locking schemes. It closes the directory and file
@@ -23295,36 +24575,23 @@ end_unlock:
 */
 static int closeUnixFile(sqlite3_file *id){
   unixFile *pFile = (unixFile*)id;
-  if( pFile ){
-    if( pFile->dirfd>=0 ){
-      int err = close(pFile->dirfd);
-      if( err ){
-        pFile->lastErrno = errno;
-        return SQLITE_IOERR_DIR_CLOSE;
-      }else{
-        pFile->dirfd=-1;
-      }
-    }
-    if( pFile->h>=0 ){
-      int err = close(pFile->h);
-      if( err ){
-        pFile->lastErrno = errno;
-        return SQLITE_IOERR_CLOSE;
-      }
-    }
-#if OS_VXWORKS
-    if( pFile->pId ){
-      if( pFile->isDelete ){
-        unlink(pFile->pId->zCanonicalName);
-      }
-      vxworksReleaseFileId(pFile->pId);
-      pFile->pId = 0;
-    }
-#endif
-    OSTRACE2("CLOSE   %-3d\n", pFile->h);
-    OpenCounter(-1);
-    memset(pFile, 0, sizeof(unixFile));
+  if( pFile->h>=0 ){
+    robust_close(pFile, pFile->h, __LINE__);
+    pFile->h = -1;
   }
+#if OS_VXWORKS
+  if( pFile->pId ){
+    if( pFile->ctrlFlags & UNIXFILE_DELETE ){
+      osUnlink(pFile->pId->zCanonicalName);
+    }
+    vxworksReleaseFileId(pFile->pId);
+    pFile->pId = 0;
+  }
+#endif
+  OSTRACE(("CLOSE   %-3d\n", pFile->h));
+  OpenCounter(-1);
+  sqlite3_free(pFile->pUnused);
+  memset(pFile, 0, sizeof(unixFile));
   return SQLITE_OK;
 }
 
@@ -23333,33 +24600,25 @@ static int closeUnixFile(sqlite3_file *id){
 */
 static int unixClose(sqlite3_file *id){
   int rc = SQLITE_OK;
-  if( id ){
-    unixFile *pFile = (unixFile *)id;
-    unixUnlock(id, NO_LOCK);
-    unixEnterMutex();
-    if( pFile->pOpen && pFile->pOpen->nLock ){
-      /* If there are outstanding locks, do not actually close the file just
-      ** yet because that would clear those locks.  Instead, add the file
-      ** descriptor to pOpen->aPending.  It will be automatically closed when
-      ** the last lock is cleared.
-      */
-      int *aNew;
-      struct unixOpenCnt *pOpen = pFile->pOpen;
-      aNew = sqlite3_realloc(pOpen->aPending, (pOpen->nPending+1)*sizeof(int) );
-      if( aNew==0 ){
-        /* If a malloc fails, just leak the file descriptor */
-      }else{
-        pOpen->aPending = aNew;
-        pOpen->aPending[pOpen->nPending] = pFile->h;
-        pOpen->nPending++;
-        pFile->h = -1;
-      }
-    }
-    releaseLockInfo(pFile->pLock);
-    releaseOpenCnt(pFile->pOpen);
-    rc = closeUnixFile(id);
-    unixLeaveMutex();
+  unixFile *pFile = (unixFile *)id;
+  unixUnlock(id, NO_LOCK);
+  unixEnterMutex();
+
+  /* unixFile.pInode is always valid here. Otherwise, a different close
+  ** routine (e.g. nolockClose()) would be called instead.
+  */
+  assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 );
+  if( ALWAYS(pFile->pInode) && pFile->pInode->nLock ){
+    /* If there are outstanding locks, do not actually close the file just
+    ** yet because that would clear those locks.  Instead, add the file
+    ** descriptor to pInode->pUnused list.  It will be automatically closed 
+    ** when the last lock is cleared.
+    */
+    setPendingFd(pFile);
   }
+  releaseInodeInfo(pFile);
+  rc = closeUnixFile(id);
+  unixLeaveMutex();
   return rc;
 }
 
@@ -23410,9 +24669,9 @@ static int nolockClose(sqlite3_file *id) {
 /******************************************************************************
 ************************* Begin dot-file Locking ******************************
 **
-** The dotfile locking implementation uses the existing of separate lock
-** files in order to control access to the database.  This works on just
-** about every filesystem imaginable.  But there are serious downsides:
+** The dotfile locking implementation uses the existance of separate lock
+** files (really a directory) to control access to the database.  This works
+** on just about every filesystem imaginable.  But there are serious downsides:
 **
 **    (1)  There is zero concurrency.  A single reader blocks all other
 **         connections from reading or writing the database.
@@ -23423,15 +24682,15 @@ static int nolockClose(sqlite3_file *id) {
 ** Nevertheless, a dotlock is an appropriate locking mode for use if no
 ** other locking strategy is available.
 **
-** Dotfile locking works by creating a file in the same directory as the
-** database and with the same name but with a ".lock" extension added.
-** The existance of a lock file implies an EXCLUSIVE lock.  All other lock
-** types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
+** Dotfile locking works by creating a subdirectory in the same directory as
+** the database and with the same name but with a ".lock" extension added.
+** The existance of a lock directory implies an EXCLUSIVE lock.  All other
+** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
 */
 
 /*
 ** The file suffix added to the data base filename in order to create the
-** lock file.
+** lock directory.
 */
 #define DOTLOCK_SUFFIX ".lock"
 
@@ -23455,22 +24714,22 @@ static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) {
   assert( pFile );
 
   /* Check if a thread in this process holds such a lock */
-  if( pFile->locktype>SHARED_LOCK ){
+  if( pFile->eFileLock>SHARED_LOCK ){
     /* Either this connection or some other connection in the same process
     ** holds a lock on the file.  No need to check further. */
     reserved = 1;
   }else{
     /* The lock is held if and only if the lockfile exists */
     const char *zLockFile = (const char*)pFile->lockingContext;
-    reserved = access(zLockFile, 0)==0;
+    reserved = osAccess(zLockFile, 0)==0;
   }
-  OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
+  OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, rc, reserved));
   *pResOut = reserved;
   return rc;
 }
 
 /*
-** Lock the file with the lock specified by parameter locktype - one
+** Lock the file with the lock specified by parameter eFileLock - one
 ** of the following:
 **
 **     (1) SHARED_LOCK
@@ -23496,9 +24755,8 @@ static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) {
 ** With dotfile locking, we really only support state (4): EXCLUSIVE.
 ** But we track the other locking levels internally.
 */
-static int dotlockLock(sqlite3_file *id, int locktype) {
+static int dotlockLock(sqlite3_file *id, int eFileLock) {
   unixFile *pFile = (unixFile*)id;
-  int fd;
   char *zLockFile = (char *)pFile->lockingContext;
   int rc = SQLITE_OK;
 
@@ -23506,19 +24764,21 @@ static int dotlockLock(sqlite3_file *id, int locktype) {
   /* If we have any lock, then the lock file already exists.  All we have
   ** to do is adjust our internal record of the lock level.
   */
-  if( pFile->locktype > NO_LOCK ){
-    pFile->locktype = locktype;
-#if !OS_VXWORKS
+  if( pFile->eFileLock > NO_LOCK ){
+    pFile->eFileLock = eFileLock;
     /* Always update the timestamp on the old file */
+#ifdef HAVE_UTIME
+    utime(zLockFile, NULL);
+#else
     utimes(zLockFile, NULL);
 #endif
     return SQLITE_OK;
   }
   
   /* grab an exclusive lock */
-  fd = open(zLockFile,O_RDONLY|O_CREAT|O_EXCL,0600);
-  if( fd<0 ){
-    /* failed to open/create the file, someone else may have stolen the lock */
+  rc = osMkdir(zLockFile, 0777);
+  if( rc<0 ){
+    /* failed to open/create the lock directory */
     int tErrno = errno;
     if( EEXIST == tErrno ){
       rc = SQLITE_BUSY;
@@ -23530,18 +24790,14 @@ static int dotlockLock(sqlite3_file *id, int locktype) {
     }
     return rc;
   } 
-  if( close(fd) ){
-    pFile->lastErrno = errno;
-    rc = SQLITE_IOERR_CLOSE;
-  }
   
   /* got it, set the type and return ok */
-  pFile->locktype = locktype;
+  pFile->eFileLock = eFileLock;
   return rc;
 }
 
 /*
-** Lower the locking level on file descriptor pFile to locktype.  locktype
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
@@ -23549,41 +24805,45 @@ static int dotlockLock(sqlite3_file *id, int locktype) {
 **
 ** When the locking level reaches NO_LOCK, delete the lock file.
 */
-static int dotlockUnlock(sqlite3_file *id, int locktype) {
+static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
   unixFile *pFile = (unixFile*)id;
   char *zLockFile = (char *)pFile->lockingContext;
+  int rc;
 
   assert( pFile );
-  OSTRACE5("UNLOCK  %d %d was %d pid=%d\n", pFile->h, locktype,
-	   pFile->locktype, getpid());
-  assert( locktype<=SHARED_LOCK );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
+           pFile->eFileLock, getpid()));
+  assert( eFileLock<=SHARED_LOCK );
   
   /* no-op if possible */
-  if( pFile->locktype==locktype ){
+  if( pFile->eFileLock==eFileLock ){
     return SQLITE_OK;
   }
 
   /* To downgrade to shared, simply update our internal notion of the
   ** lock state.  No need to mess with the file on disk.
   */
-  if( locktype==SHARED_LOCK ){
-    pFile->locktype = SHARED_LOCK;
+  if( eFileLock==SHARED_LOCK ){
+    pFile->eFileLock = SHARED_LOCK;
     return SQLITE_OK;
   }
   
   /* To fully unlock the database, delete the lock file */
-  assert( locktype==NO_LOCK );
-  if( unlink(zLockFile) ){
-    int rc, tErrno = errno;
+  assert( eFileLock==NO_LOCK );
+  rc = osRmdir(zLockFile);
+  if( rc<0 && errno==ENOTDIR ) rc = osUnlink(zLockFile);
+  if( rc<0 ){
+    int tErrno = errno;
+    rc = 0;
     if( ENOENT != tErrno ){
-      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
+      rc = SQLITE_IOERR_UNLOCK;
     }
     if( IS_LOCK_ERROR(rc) ){
       pFile->lastErrno = tErrno;
     }
     return rc; 
   }
-  pFile->locktype = NO_LOCK;
+  pFile->eFileLock = NO_LOCK;
   return SQLITE_OK;
 }
 
@@ -23620,6 +24880,20 @@ static int dotlockClose(sqlite3_file *id) {
 */
 #if SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS
 
+/*
+** Retry flock() calls that fail with EINTR
+*/
+#ifdef EINTR
+static int robust_flock(int fd, int op){
+  int rc;
+  do{ rc = flock(fd,op); }while( rc<0 && errno==EINTR );
+  return rc;
+}
+#else
+# define robust_flock(a,b) flock(a,b)
+#endif
+     
+
 /*
 ** This routine checks if there is a RESERVED lock held on the specified
 ** file by this or any other process. If such a lock is held, set *pResOut
@@ -23636,21 +24910,21 @@ static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
   assert( pFile );
   
   /* Check if a thread in this process holds such a lock */
-  if( pFile->locktype>SHARED_LOCK ){
+  if( pFile->eFileLock>SHARED_LOCK ){
     reserved = 1;
   }
   
   /* Otherwise see if some other process holds it. */
   if( !reserved ){
     /* attempt to get the lock */
-    int lrc = flock(pFile->h, LOCK_EX | LOCK_NB);
+    int lrc = robust_flock(pFile->h, LOCK_EX | LOCK_NB);
     if( !lrc ){
       /* got the lock, unlock it */
-      lrc = flock(pFile->h, LOCK_UN);
+      lrc = robust_flock(pFile->h, LOCK_UN);
       if ( lrc ) {
         int tErrno = errno;
         /* unlock failed with an error */
-        lrc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK); 
+        lrc = SQLITE_IOERR_UNLOCK; 
         if( IS_LOCK_ERROR(lrc) ){
           pFile->lastErrno = tErrno;
           rc = lrc;
@@ -23667,7 +24941,7 @@ static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
       }
     }
   }
-  OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
+  OSTRACE(("TEST WR-LOCK %d %d %d (flock)\n", pFile->h, rc, reserved));
 
 #ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
   if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){
@@ -23680,7 +24954,7 @@ static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
 }
 
 /*
-** Lock the file with the lock specified by parameter locktype - one
+** Lock the file with the lock specified by parameter eFileLock - one
 ** of the following:
 **
 **     (1) SHARED_LOCK
@@ -23708,7 +24982,7 @@ static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
 ** This routine will only increase a lock.  Use the sqlite3OsUnlock()
 ** routine to lower a locking level.
 */
-static int flockLock(sqlite3_file *id, int locktype) {
+static int flockLock(sqlite3_file *id, int eFileLock) {
   int rc = SQLITE_OK;
   unixFile *pFile = (unixFile*)id;
 
@@ -23716,14 +24990,14 @@ static int flockLock(sqlite3_file *id, int locktype) {
 
   /* if we already have a lock, it is exclusive.  
   ** Just adjust level and punt on outta here. */
-  if (pFile->locktype > NO_LOCK) {
-    pFile->locktype = locktype;
+  if (pFile->eFileLock > NO_LOCK) {
+    pFile->eFileLock = eFileLock;
     return SQLITE_OK;
   }
   
   /* grab an exclusive lock */
   
-  if (flock(pFile->h, LOCK_EX | LOCK_NB)) {
+  if (robust_flock(pFile->h, LOCK_EX | LOCK_NB)) {
     int tErrno = errno;
     /* didn't get, must be busy */
     rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
@@ -23732,10 +25006,10 @@ static int flockLock(sqlite3_file *id, int locktype) {
     }
   } else {
     /* got it, set the type and return ok */
-    pFile->locktype = locktype;
+    pFile->eFileLock = eFileLock;
   }
-  OSTRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
-           rc==SQLITE_OK ? "ok" : "failed");
+  OSTRACE(("LOCK    %d %s %s (flock)\n", pFile->h, azFileLock(eFileLock), 
+           rc==SQLITE_OK ? "ok" : "failed"));
 #ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
   if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){
     rc = SQLITE_BUSY;
@@ -23746,48 +25020,39 @@ static int flockLock(sqlite3_file *id, int locktype) {
 
 
 /*
-** Lower the locking level on file descriptor pFile to locktype.  locktype
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
 */
-static int flockUnlock(sqlite3_file *id, int locktype) {
+static int flockUnlock(sqlite3_file *id, int eFileLock) {
   unixFile *pFile = (unixFile*)id;
   
   assert( pFile );
-  OSTRACE5("UNLOCK  %d %d was %d pid=%d\n", pFile->h, locktype,
-           pFile->locktype, getpid());
-  assert( locktype<=SHARED_LOCK );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (flock)\n", pFile->h, eFileLock,
+           pFile->eFileLock, getpid()));
+  assert( eFileLock<=SHARED_LOCK );
   
   /* no-op if possible */
-  if( pFile->locktype==locktype ){
+  if( pFile->eFileLock==eFileLock ){
     return SQLITE_OK;
   }
   
   /* shared can just be set because we always have an exclusive */
-  if (locktype==SHARED_LOCK) {
-    pFile->locktype = locktype;
+  if (eFileLock==SHARED_LOCK) {
+    pFile->eFileLock = eFileLock;
     return SQLITE_OK;
   }
   
   /* no, really, unlock. */
-  int rc = flock(pFile->h, LOCK_UN);
-  if (rc) {
-    int r, tErrno = errno;
-    r = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
-    if( IS_LOCK_ERROR(r) ){
-      pFile->lastErrno = tErrno;
-    }
+  if( robust_flock(pFile->h, LOCK_UN) ){
 #ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
-    if( (r & SQLITE_IOERR) == SQLITE_IOERR ){
-      r = SQLITE_BUSY;
-    }
+    return SQLITE_OK;
 #endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
-    
-    return r;
-  } else {
-    pFile->locktype = NO_LOCK;
+    return SQLITE_IOERR_UNLOCK;
+  }else{
+    pFile->eFileLock = NO_LOCK;
     return SQLITE_OK;
   }
 }
@@ -23835,13 +25100,13 @@ static int semCheckReservedLock(sqlite3_file *id, int *pResOut) {
   assert( pFile );
 
   /* Check if a thread in this process holds such a lock */
-  if( pFile->locktype>SHARED_LOCK ){
+  if( pFile->eFileLock>SHARED_LOCK ){
     reserved = 1;
   }
   
   /* Otherwise see if some other process holds it. */
   if( !reserved ){
-    sem_t *pSem = pFile->pOpen->pSem;
+    sem_t *pSem = pFile->pInode->pSem;
     struct stat statBuf;
 
     if( sem_trywait(pSem)==-1 ){
@@ -23851,21 +25116,21 @@ static int semCheckReservedLock(sqlite3_file *id, int *pResOut) {
         pFile->lastErrno = tErrno;
       } else {
         /* someone else has the lock when we are in NO_LOCK */
-        reserved = (pFile->locktype < SHARED_LOCK);
+        reserved = (pFile->eFileLock < SHARED_LOCK);
       }
     }else{
       /* we could have it if we want it */
       sem_post(pSem);
     }
   }
-  OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
+  OSTRACE(("TEST WR-LOCK %d %d %d (sem)\n", pFile->h, rc, reserved));
 
   *pResOut = reserved;
   return rc;
 }
 
 /*
-** Lock the file with the lock specified by parameter locktype - one
+** Lock the file with the lock specified by parameter eFileLock - one
 ** of the following:
 **
 **     (1) SHARED_LOCK
@@ -23893,16 +25158,16 @@ static int semCheckReservedLock(sqlite3_file *id, int *pResOut) {
 ** This routine will only increase a lock.  Use the sqlite3OsUnlock()
 ** routine to lower a locking level.
 */
-static int semLock(sqlite3_file *id, int locktype) {
+static int semLock(sqlite3_file *id, int eFileLock) {
   unixFile *pFile = (unixFile*)id;
   int fd;
-  sem_t *pSem = pFile->pOpen->pSem;
+  sem_t *pSem = pFile->pInode->pSem;
   int rc = SQLITE_OK;
 
   /* if we already have a lock, it is exclusive.  
   ** Just adjust level and punt on outta here. */
-  if (pFile->locktype > NO_LOCK) {
-    pFile->locktype = locktype;
+  if (pFile->eFileLock > NO_LOCK) {
+    pFile->eFileLock = eFileLock;
     rc = SQLITE_OK;
     goto sem_end_lock;
   }
@@ -23914,37 +25179,37 @@ static int semLock(sqlite3_file *id, int locktype) {
   }
 
   /* got it, set the type and return ok */
-  pFile->locktype = locktype;
+  pFile->eFileLock = eFileLock;
 
  sem_end_lock:
   return rc;
 }
 
 /*
-** Lower the locking level on file descriptor pFile to locktype.  locktype
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
 */
-static int semUnlock(sqlite3_file *id, int locktype) {
+static int semUnlock(sqlite3_file *id, int eFileLock) {
   unixFile *pFile = (unixFile*)id;
-  sem_t *pSem = pFile->pOpen->pSem;
+  sem_t *pSem = pFile->pInode->pSem;
 
   assert( pFile );
   assert( pSem );
-  OSTRACE5("UNLOCK  %d %d was %d pid=%d\n", pFile->h, locktype,
-	   pFile->locktype, getpid());
-  assert( locktype<=SHARED_LOCK );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (sem)\n", pFile->h, eFileLock,
+           pFile->eFileLock, getpid()));
+  assert( eFileLock<=SHARED_LOCK );
   
   /* no-op if possible */
-  if( pFile->locktype==locktype ){
+  if( pFile->eFileLock==eFileLock ){
     return SQLITE_OK;
   }
   
   /* shared can just be set because we always have an exclusive */
-  if (locktype==SHARED_LOCK) {
-    pFile->locktype = locktype;
+  if (eFileLock==SHARED_LOCK) {
+    pFile->eFileLock = eFileLock;
     return SQLITE_OK;
   }
   
@@ -23957,7 +25222,7 @@ static int semUnlock(sqlite3_file *id, int locktype) {
     }
     return rc; 
   }
-  pFile->locktype = NO_LOCK;
+  pFile->eFileLock = NO_LOCK;
   return SQLITE_OK;
 }
 
@@ -23970,10 +25235,9 @@ static int semClose(sqlite3_file *id) {
     semUnlock(id, NO_LOCK);
     assert( pFile );
     unixEnterMutex();
-    releaseLockInfo(pFile->pLock);
-    releaseOpenCnt(pFile->pOpen);
-    closeUnixFile(id);
+    releaseInodeInfo(pFile);
     unixLeaveMutex();
+    closeUnixFile(id);
   }
   return SQLITE_OK;
 }
@@ -24002,7 +25266,7 @@ static int semClose(sqlite3_file *id) {
 */
 typedef struct afpLockingContext afpLockingContext;
 struct afpLockingContext {
-  unsigned long long sharedByte;
+  int reserved;
   const char *dbPath;             /* Name of the open file */
 };
 
@@ -24040,15 +25304,15 @@ static int afpSetLock(
   pb.length = length; 
   pb.fd = pFile->h;
   
-  OSTRACE6("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n", 
+  OSTRACE(("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n", 
     (setLockFlag?"ON":"OFF"), pFile->h, (pb.fd==-1?"[testval-1]":""),
-    offset, length);
+    offset, length));
   err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
   if ( err==-1 ) {
     int rc;
     int tErrno = errno;
-    OSTRACE4("AFPSETLOCK failed to fsctl() '%s' %d %s\n",
-             path, tErrno, strerror(tErrno));
+    OSTRACE(("AFPSETLOCK failed to fsctl() '%s' %d %s\n",
+             path, tErrno, strerror(tErrno)));
 #ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
     rc = SQLITE_BUSY;
 #else
@@ -24074,14 +25338,20 @@ static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){
   int rc = SQLITE_OK;
   int reserved = 0;
   unixFile *pFile = (unixFile*)id;
+  afpLockingContext *context;
   
   SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
   
   assert( pFile );
-  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+  context = (afpLockingContext *) pFile->lockingContext;
+  if( context->reserved ){
+    *pResOut = 1;
+    return SQLITE_OK;
+  }
+  unixEnterMutex(); /* Because pFile->pInode is shared across threads */
   
   /* Check if a thread in this process holds such a lock */
-  if( pFile->locktype>SHARED_LOCK ){
+  if( pFile->pInode->eFileLock>SHARED_LOCK ){
     reserved = 1;
   }
   
@@ -24103,14 +25373,15 @@ static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){
     }
   }
   
-  OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
+  unixLeaveMutex();
+  OSTRACE(("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved));
   
   *pResOut = reserved;
   return rc;
 }
 
 /*
-** Lock the file with the lock specified by parameter locktype - one
+** Lock the file with the lock specified by parameter eFileLock - one
 ** of the following:
 **
 **     (1) SHARED_LOCK
@@ -24133,49 +25404,72 @@ static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){
 ** This routine will only increase a lock.  Use the sqlite3OsUnlock()
 ** routine to lower a locking level.
 */
-static int afpLock(sqlite3_file *id, int locktype){
+static int afpLock(sqlite3_file *id, int eFileLock){
   int rc = SQLITE_OK;
   unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode = pFile->pInode;
   afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
   
   assert( pFile );
-  OSTRACE5("LOCK    %d %s was %s pid=%d\n", pFile->h,
-         locktypeName(locktype), locktypeName(pFile->locktype), getpid());
+  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h,
+           azFileLock(eFileLock), azFileLock(pFile->eFileLock),
+           azFileLock(pInode->eFileLock), pInode->nShared , getpid()));
 
   /* If there is already a lock of this type or more restrictive on the
   ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
   ** unixEnterMutex() hasn't been called yet.
   */
-  if( pFile->locktype>=locktype ){
-    OSTRACE3("LOCK    %d %s ok (already held)\n", pFile->h,
-           locktypeName(locktype));
+  if( pFile->eFileLock>=eFileLock ){
+    OSTRACE(("LOCK    %d %s ok (already held) (afp)\n", pFile->h,
+           azFileLock(eFileLock)));
     return SQLITE_OK;
   }
 
   /* Make sure the locking sequence is correct
+  **  (1) We never move from unlocked to anything higher than shared lock.
+  **  (2) SQLite never explicitly requests a pendig lock.
+  **  (3) A shared lock is always held when a reserve lock is requested.
   */
-  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
-  assert( locktype!=PENDING_LOCK );
-  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
+  assert( eFileLock!=PENDING_LOCK );
+  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );
   
-  /* This mutex is needed because pFile->pLock is shared across threads
+  /* This mutex is needed because pFile->pInode is shared across threads
   */
   unixEnterMutex();
+  pInode = pFile->pInode;
 
-  /* Make sure the current thread owns the pFile.
+  /* If some thread using this PID has a lock via a different unixFile*
+  ** handle that precludes the requested lock, return BUSY.
   */
-  rc = transferOwnership(pFile);
-  if( rc!=SQLITE_OK ){
-    unixLeaveMutex();
-    return rc;
+  if( (pFile->eFileLock!=pInode->eFileLock && 
+       (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
+     ){
+    rc = SQLITE_BUSY;
+    goto afp_end_lock;
+  }
+  
+  /* If a SHARED lock is requested, and some thread using this PID already
+  ** has a SHARED or RESERVED lock, then increment reference counts and
+  ** return SQLITE_OK.
+  */
+  if( eFileLock==SHARED_LOCK && 
+     (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
+    assert( eFileLock==SHARED_LOCK );
+    assert( pFile->eFileLock==0 );
+    assert( pInode->nShared>0 );
+    pFile->eFileLock = SHARED_LOCK;
+    pInode->nShared++;
+    pInode->nLock++;
+    goto afp_end_lock;
   }
     
   /* A PENDING lock is needed before acquiring a SHARED lock and before
   ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
   ** be released.
   */
-  if( locktype==SHARED_LOCK 
-      || (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
+  if( eFileLock==SHARED_LOCK 
+      || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK)
   ){
     int failed;
     failed = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 1);
@@ -24188,15 +25482,20 @@ static int afpLock(sqlite3_file *id, int locktype){
   /* If control gets to this point, then actually go ahead and make
   ** operating system calls for the specified lock.
   */
-  if( locktype==SHARED_LOCK ){
-    int lk, lrc1, lrc2, lrc1Errno;
+  if( eFileLock==SHARED_LOCK ){
+    int lrc1, lrc2, lrc1Errno = 0;
+    long lk, mask;
     
+    assert( pInode->nShared==0 );
+    assert( pInode->eFileLock==0 );
+        
+    mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff;
     /* Now get the read-lock SHARED_LOCK */
     /* note that the quality of the randomness doesn't matter that much */
     lk = random(); 
-    context->sharedByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1);
+    pInode->sharedByte = (lk & mask)%(SHARED_SIZE - 1);
     lrc1 = afpSetLock(context->dbPath, pFile, 
-          SHARED_FIRST+context->sharedByte, 1, 1);
+          SHARED_FIRST+pInode->sharedByte, 1, 1);
     if( IS_LOCK_ERROR(lrc1) ){
       lrc1Errno = pFile->lastErrno;
     }
@@ -24213,34 +25512,42 @@ static int afpLock(sqlite3_file *id, int locktype){
     } else if( lrc1 != SQLITE_OK ) {
       rc = lrc1;
     } else {
-      pFile->locktype = SHARED_LOCK;
-      pFile->pOpen->nLock++;
+      pFile->eFileLock = SHARED_LOCK;
+      pInode->nLock++;
+      pInode->nShared = 1;
     }
+  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
+    /* We are trying for an exclusive lock but another thread in this
+     ** same process is still holding a shared lock. */
+    rc = SQLITE_BUSY;
   }else{
     /* The request was for a RESERVED or EXCLUSIVE lock.  It is
     ** assumed that there is a SHARED or greater lock on the file
     ** already.
     */
     int failed = 0;
-    assert( 0!=pFile->locktype );
-    if (locktype >= RESERVED_LOCK && pFile->locktype < RESERVED_LOCK) {
+    assert( 0!=pFile->eFileLock );
+    if (eFileLock >= RESERVED_LOCK && pFile->eFileLock < RESERVED_LOCK) {
         /* Acquire a RESERVED lock */
         failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
+      if( !failed ){
+        context->reserved = 1;
+      }
     }
-    if (!failed && locktype == EXCLUSIVE_LOCK) {
+    if (!failed && eFileLock == EXCLUSIVE_LOCK) {
       /* Acquire an EXCLUSIVE lock */
         
       /* Remove the shared lock before trying the range.  we'll need to 
       ** reestablish the shared lock if we can't get the  afpUnlock
       */
       if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
-                         context->sharedByte, 1, 0)) ){
+                         pInode->sharedByte, 1, 0)) ){
         int failed2 = SQLITE_OK;
         /* now attemmpt to get the exclusive lock range */
         failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST, 
                                SHARED_SIZE, 1);
         if( failed && (failed2 = afpSetLock(context->dbPath, pFile, 
-                       SHARED_FIRST + context->sharedByte, 1, 1)) ){
+                       SHARED_FIRST + pInode->sharedByte, 1, 1)) ){
           /* Can't reestablish the shared lock.  Sqlite can't deal, this is
           ** a critical I/O error
           */
@@ -24258,90 +25565,124 @@ static int afpLock(sqlite3_file *id, int locktype){
   }
   
   if( rc==SQLITE_OK ){
-    pFile->locktype = locktype;
-  }else if( locktype==EXCLUSIVE_LOCK ){
-    pFile->locktype = PENDING_LOCK;
+    pFile->eFileLock = eFileLock;
+    pInode->eFileLock = eFileLock;
+  }else if( eFileLock==EXCLUSIVE_LOCK ){
+    pFile->eFileLock = PENDING_LOCK;
+    pInode->eFileLock = PENDING_LOCK;
   }
   
 afp_end_lock:
   unixLeaveMutex();
-  OSTRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
-         rc==SQLITE_OK ? "ok" : "failed");
+  OSTRACE(("LOCK    %d %s %s (afp)\n", pFile->h, azFileLock(eFileLock), 
+         rc==SQLITE_OK ? "ok" : "failed"));
   return rc;
 }
 
 /*
-** Lower the locking level on file descriptor pFile to locktype.  locktype
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
 */
-static int afpUnlock(sqlite3_file *id, int locktype) {
+static int afpUnlock(sqlite3_file *id, int eFileLock) {
   int rc = SQLITE_OK;
   unixFile *pFile = (unixFile*)id;
-  afpLockingContext *pCtx = (afpLockingContext *) pFile->lockingContext;
+  unixInodeInfo *pInode;
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+  int skipShared = 0;
+#ifdef SQLITE_TEST
+  int h = pFile->h;
+#endif
 
   assert( pFile );
-  OSTRACE5("UNLOCK  %d %d was %d pid=%d\n", pFile->h, locktype,
-         pFile->locktype, getpid());
+  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, eFileLock,
+           pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
+           getpid()));
 
-  assert( locktype<=SHARED_LOCK );
-  if( pFile->locktype<=locktype ){
+  assert( eFileLock<=SHARED_LOCK );
+  if( pFile->eFileLock<=eFileLock ){
     return SQLITE_OK;
   }
-  if( CHECK_THREADID(pFile) ){
-    return SQLITE_MISUSE;
-  }
   unixEnterMutex();
-  if( pFile->locktype>SHARED_LOCK ){
+  pInode = pFile->pInode;
+  assert( pInode->nShared!=0 );
+  if( pFile->eFileLock>SHARED_LOCK ){
+    assert( pInode->eFileLock==pFile->eFileLock );
+    SimulateIOErrorBenign(1);
+    SimulateIOError( h=(-1) )
+    SimulateIOErrorBenign(0);
     
-    if( pFile->locktype==EXCLUSIVE_LOCK ){
-      rc = afpSetLock(pCtx->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
-      if( rc==SQLITE_OK && locktype==SHARED_LOCK ){
+#ifdef SQLITE_DEBUG
+    /* When reducing a lock such that other processes can start
+    ** reading the database file again, make sure that the
+    ** transaction counter was updated if any part of the database
+    ** file changed.  If the transaction counter is not updated,
+    ** other connections to the same file might not realize that
+    ** the file has changed and hence might not know to flush their
+    ** cache.  The use of a stale cache can lead to database corruption.
+    */
+    assert( pFile->inNormalWrite==0
+           || pFile->dbUpdate==0
+           || pFile->transCntrChng==1 );
+    pFile->inNormalWrite = 0;
+#endif
+    
+    if( pFile->eFileLock==EXCLUSIVE_LOCK ){
+      rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
+      if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1) ){
         /* only re-establish the shared lock if necessary */
-        int sharedLockByte = SHARED_FIRST+pCtx->sharedByte;
-        rc = afpSetLock(pCtx->dbPath, pFile, sharedLockByte, 1, 1);
+        int sharedLockByte = SHARED_FIRST+pInode->sharedByte;
+        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1);
+      } else {
+        skipShared = 1;
       }
     }
-    if( rc==SQLITE_OK && pFile->locktype>=PENDING_LOCK ){
-      rc = afpSetLock(pCtx->dbPath, pFile, PENDING_BYTE, 1, 0);
+    if( rc==SQLITE_OK && pFile->eFileLock>=PENDING_LOCK ){
+      rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
     } 
-    if( rc==SQLITE_OK && pFile->locktype>=RESERVED_LOCK ){
-      rc = afpSetLock(pCtx->dbPath, pFile, RESERVED_BYTE, 1, 0);
+    if( rc==SQLITE_OK && pFile->eFileLock>=RESERVED_LOCK && context->reserved ){
+      rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
+      if( !rc ){ 
+        context->reserved = 0; 
+      }
+    }
+    if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1)){
+      pInode->eFileLock = SHARED_LOCK;
     }
-  }else if( locktype==NO_LOCK ){
-    /* clear the shared lock */
-    int sharedLockByte = SHARED_FIRST+pCtx->sharedByte;
-    rc = afpSetLock(pCtx->dbPath, pFile, sharedLockByte, 1, 0);
   }
+  if( rc==SQLITE_OK && eFileLock==NO_LOCK ){
 
-  if( rc==SQLITE_OK ){
-    if( locktype==NO_LOCK ){
-      struct unixOpenCnt *pOpen = pFile->pOpen;
-      pOpen->nLock--;
-      assert( pOpen->nLock>=0 );
-      if( pOpen->nLock==0 && pOpen->nPending>0 ){
-        int i;
-        for(i=0; i<pOpen->nPending; i++){
-          if( pOpen->aPending[i] < 0 ) continue;
-          if( close(pOpen->aPending[i]) ){
-            pFile->lastErrno = errno;
-            rc = SQLITE_IOERR_CLOSE;
-          }else{
-            pOpen->aPending[i] = -1;
-          }
-        }
-        if( rc==SQLITE_OK ){
-          sqlite3_free(pOpen->aPending);
-          pOpen->nPending = 0;
-          pOpen->aPending = 0;
-        }
+    /* Decrement the shared lock counter.  Release the lock using an
+    ** OS call only when all threads in this same process have released
+    ** the lock.
+    */
+    unsigned long long sharedLockByte = SHARED_FIRST+pInode->sharedByte;
+    pInode->nShared--;
+    if( pInode->nShared==0 ){
+      SimulateIOErrorBenign(1);
+      SimulateIOError( h=(-1) )
+      SimulateIOErrorBenign(0);
+      if( !skipShared ){
+        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0);
+      }
+      if( !rc ){
+        pInode->eFileLock = NO_LOCK;
+        pFile->eFileLock = NO_LOCK;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      pInode->nLock--;
+      assert( pInode->nLock>=0 );
+      if( pInode->nLock==0 ){
+        closePendingFds(pFile);
       }
     }
   }
+  
   unixLeaveMutex();
-  if( rc==SQLITE_OK ) pFile->locktype = locktype;
+  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;
   return rc;
 }
 
@@ -24349,34 +25690,25 @@ static int afpUnlock(sqlite3_file *id, int locktype) {
 ** Close a file & cleanup AFP specific locking context 
 */
 static int afpClose(sqlite3_file *id) {
+  int rc = SQLITE_OK;
   if( id ){
     unixFile *pFile = (unixFile*)id;
     afpUnlock(id, NO_LOCK);
     unixEnterMutex();
-    if( pFile->pOpen && pFile->pOpen->nLock ){
+    if( pFile->pInode && pFile->pInode->nLock ){
       /* If there are outstanding locks, do not actually close the file just
       ** yet because that would clear those locks.  Instead, add the file
-      ** descriptor to pOpen->aPending.  It will be automatically closed when
+      ** descriptor to pInode->aPending.  It will be automatically closed when
       ** the last lock is cleared.
       */
-      int *aNew;
-      struct unixOpenCnt *pOpen = pFile->pOpen;
-      aNew = sqlite3_realloc(pOpen->aPending, (pOpen->nPending+1)*sizeof(int) );
-      if( aNew==0 ){
-        /* If a malloc fails, just leak the file descriptor */
-      }else{
-        pOpen->aPending = aNew;
-        pOpen->aPending[pOpen->nPending] = pFile->h;
-        pOpen->nPending++;
-        pFile->h = -1;
-      }
+      setPendingFd(pFile);
     }
-    releaseOpenCnt(pFile->pOpen);
+    releaseInodeInfo(pFile);
     sqlite3_free(pFile->lockingContext);
-    closeUnixFile(id);
+    rc = closeUnixFile(id);
     unixLeaveMutex();
   }
-  return SQLITE_OK;
+  return rc;
 }
 
 #endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
@@ -24389,6 +25721,29 @@ static int afpClose(sqlite3_file *id) {
 ********************* End of the AFP lock implementation **********************
 ******************************************************************************/
 
+/******************************************************************************
+*************************** Begin NFS Locking ********************************/
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+ ** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+ ** must be either NO_LOCK or SHARED_LOCK.
+ **
+ ** If the locking level of the file descriptor is already at or below
+ ** the requested locking level, this routine is a no-op.
+ */
+static int nfsUnlock(sqlite3_file *id, int eFileLock){
+  return posixUnlock(id, eFileLock, 1);
+}
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The code above is the NFS lock implementation.  The code is specific
+** to MacOSX and does not work on other unix platforms.  No alternative
+** is available.  
+**
+********************* End of the NFS lock implementation **********************
+******************************************************************************/
 
 /******************************************************************************
 **************** Non-locking sqlite3_file methods *****************************
@@ -24415,33 +25770,48 @@ static int afpClose(sqlite3_file *id) {
 */
 static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
   int got;
+  int prior = 0;
+#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
   i64 newOffset;
-  TIMER_START;
-#if defined(USE_PREAD)
-  got = pread(id->h, pBuf, cnt, offset);
-  SimulateIOError( got = -1 );
-#elif defined(USE_PREAD64)
-  got = pread64(id->h, pBuf, cnt, offset);
-  SimulateIOError( got = -1 );
-#else
-  newOffset = lseek(id->h, offset, SEEK_SET);
-  SimulateIOError( newOffset-- );
-  if( newOffset!=offset ){
-    if( newOffset == -1 ){
-      ((unixFile*)id)->lastErrno = errno;
-    }else{
-      ((unixFile*)id)->lastErrno = 0;			
-    }
-    return -1;
-  }
-  got = read(id->h, pBuf, cnt);
 #endif
+  TIMER_START;
+  do{
+#if defined(USE_PREAD)
+    got = osPread(id->h, pBuf, cnt, offset);
+    SimulateIOError( got = -1 );
+#elif defined(USE_PREAD64)
+    got = osPread64(id->h, pBuf, cnt, offset);
+    SimulateIOError( got = -1 );
+#else
+    newOffset = lseek(id->h, offset, SEEK_SET);
+    SimulateIOError( newOffset-- );
+    if( newOffset!=offset ){
+      if( newOffset == -1 ){
+        ((unixFile*)id)->lastErrno = errno;
+      }else{
+        ((unixFile*)id)->lastErrno = 0;
+      }
+      return -1;
+    }
+    got = osRead(id->h, pBuf, cnt);
+#endif
+    if( got==cnt ) break;
+    if( got<0 ){
+      if( errno==EINTR ){ got = 1; continue; }
+      prior = 0;
+      ((unixFile*)id)->lastErrno = errno;
+      break;
+    }else if( got>0 ){
+      cnt -= got;
+      offset += got;
+      prior += got;
+      pBuf = (void*)(got + (char*)pBuf);
+    }
+  }while( got>0 );
   TIMER_END;
-  if( got<0 ){
-    ((unixFile*)id)->lastErrno = errno;
-  }
-  OSTRACE5("READ    %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED);
-  return got;
+  OSTRACE(("READ    %-3d %5d %7lld %llu\n",
+            id->h, got+prior, offset-prior, TIMER_ELAPSED));
+  return got+prior;
 }
 
 /*
@@ -24455,16 +25825,27 @@ static int unixRead(
   int amt,
   sqlite3_int64 offset
 ){
+  unixFile *pFile = (unixFile *)id;
   int got;
   assert( id );
-  got = seekAndRead((unixFile*)id, offset, pBuf, amt);
+
+  /* If this is a database file (not a journal, master-journal or temp
+  ** file), the bytes in the locking range should never be read or written. */
+#if 0
+  assert( pFile->pUnused==0
+       || offset>=PENDING_BYTE+512
+       || offset+amt<=PENDING_BYTE 
+  );
+#endif
+
+  got = seekAndRead(pFile, offset, pBuf, amt);
   if( got==amt ){
     return SQLITE_OK;
   }else if( got<0 ){
     /* lastErrno set by seekAndRead */
     return SQLITE_IOERR_READ;
   }else{
-    ((unixFile*)id)->lastErrno = 0; /* not a system error */
+    pFile->lastErrno = 0; /* not a system error */
     /* Unread parts of the buffer must be zero-filled */
     memset(&((char*)pBuf)[got], 0, amt-got);
     return SQLITE_IOERR_SHORT_READ;
@@ -24480,30 +25861,35 @@ static int unixRead(
 */
 static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){
   int got;
+#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
   i64 newOffset;
+#endif
   TIMER_START;
 #if defined(USE_PREAD)
-  got = pwrite(id->h, pBuf, cnt, offset);
+  do{ got = osPwrite(id->h, pBuf, cnt, offset); }while( got<0 && errno==EINTR );
 #elif defined(USE_PREAD64)
-  got = pwrite64(id->h, pBuf, cnt, offset);
+  do{ got = osPwrite64(id->h, pBuf, cnt, offset);}while( got<0 && errno==EINTR);
 #else
-  newOffset = lseek(id->h, offset, SEEK_SET);
-  if( newOffset!=offset ){
-    if( newOffset == -1 ){
-      ((unixFile*)id)->lastErrno = errno;
-    }else{
-      ((unixFile*)id)->lastErrno = 0;			
+  do{
+    newOffset = lseek(id->h, offset, SEEK_SET);
+    SimulateIOError( newOffset-- );
+    if( newOffset!=offset ){
+      if( newOffset == -1 ){
+        ((unixFile*)id)->lastErrno = errno;
+      }else{
+        ((unixFile*)id)->lastErrno = 0;
+      }
+      return -1;
     }
-    return -1;
-  }
-  got = write(id->h, pBuf, cnt);
+    got = osWrite(id->h, pBuf, cnt);
+  }while( got<0 && errno==EINTR );
 #endif
   TIMER_END;
   if( got<0 ){
     ((unixFile*)id)->lastErrno = errno;
   }
 
-  OSTRACE5("WRITE   %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED);
+  OSTRACE(("WRITE   %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED));
   return got;
 }
 
@@ -24518,48 +25904,60 @@ static int unixWrite(
   int amt,
   sqlite3_int64 offset 
 ){
+  unixFile *pFile = (unixFile*)id;
   int wrote = 0;
   assert( id );
   assert( amt>0 );
 
-#ifndef NDEBUG
+  /* If this is a database file (not a journal, master-journal or temp
+  ** file), the bytes in the locking range should never be read or written. */
+#if 0
+  assert( pFile->pUnused==0
+       || offset>=PENDING_BYTE+512
+       || offset+amt<=PENDING_BYTE 
+  );
+#endif
+
+#ifdef SQLITE_DEBUG
   /* If we are doing a normal write to a database file (as opposed to
   ** doing a hot-journal rollback or a write to some file other than a
   ** normal database file) then record the fact that the database
   ** has changed.  If the transaction counter is modified, record that
   ** fact too.
   */
-  if( ((unixFile*)id)->inNormalWrite ){
-    unixFile *pFile = (unixFile*)id;
+  if( pFile->inNormalWrite ){
     pFile->dbUpdate = 1;  /* The database has been modified */
     if( offset<=24 && offset+amt>=27 ){
+      int rc;
       char oldCntr[4];
       SimulateIOErrorBenign(1);
-      seekAndRead(pFile, 24, oldCntr, 4);
+      rc = seekAndRead(pFile, 24, oldCntr, 4);
       SimulateIOErrorBenign(0);
-      if( memcmp(oldCntr, &((char*)pBuf)[24-offset], 4)!=0 ){
+      if( rc!=4 || memcmp(oldCntr, &((char*)pBuf)[24-offset], 4)!=0 ){
         pFile->transCntrChng = 1;  /* The transaction counter has changed */
       }
     }
   }
 #endif
 
-  while( amt>0 && (wrote = seekAndWrite((unixFile*)id, offset, pBuf, amt))>0 ){
+  while( amt>0 && (wrote = seekAndWrite(pFile, offset, pBuf, amt))>0 ){
     amt -= wrote;
     offset += wrote;
     pBuf = &((char*)pBuf)[wrote];
   }
   SimulateIOError(( wrote=(-1), amt=1 ));
   SimulateDiskfullError(( wrote=0, amt=1 ));
+
   if( amt>0 ){
-    if( wrote<0 ){
+    if( wrote<0 && pFile->lastErrno!=ENOSPC ){
       /* lastErrno set by seekAndWrite */
       return SQLITE_IOERR_WRITE;
     }else{
-      ((unixFile*)id)->lastErrno = 0; /* not a system error */
+      pFile->lastErrno = 0; /* not a system error */
       return SQLITE_FULL;
     }
   }
+
   return SQLITE_OK;
 }
 
@@ -24573,10 +25971,12 @@ SQLITE_API int sqlite3_fullsync_count = 0;
 #endif
 
 /*
-** Use the fdatasync() API only if the HAVE_FDATASYNC macro is defined.
-** Otherwise use fsync() in its place.
+** We do not trust systems to provide a working fdatasync().  Some do.
+** Others do no.  To be safe, we will stick with the (slightly slower)
+** fsync(). If you know that your system does support fdatasync() correctly,
+** then simply compile with -Dfdatasync=fdatasync
 */
-#ifndef HAVE_FDATASYNC
+#if !defined(fdatasync)
 # define fdatasync fsync
 #endif
 
@@ -24602,6 +26002,19 @@ SQLITE_API int sqlite3_fullsync_count = 0;
 ** You are strongly advised *not* to deploy with SQLITE_NO_SYNC
 ** enabled, however, since with SQLITE_NO_SYNC enabled, an OS crash
 ** or power failure will likely corrupt the database file.
+**
+** SQLite sets the dataOnly flag if the size of the file is unchanged.
+** The idea behind dataOnly is that it should only write the file content
+** to disk, not the inode.  We only set dataOnly if the file size is 
+** unchanged since the file size is part of the inode.  However, 
+** Ted Ts'o tells us that fdatasync() will also write the inode if the
+** file size has changed.  The only real difference between fdatasync()
+** and fsync(), Ted tells us, is that fdatasync() will not flush the
+** inode if the mtime or owner or other inode attributes have changed.
+** We only care about the file size, not the other file attributes, so
+** as far as SQLite is concerned, an fdatasync() is always adequate.
+** So, we always use fdatasync() if it is available, regardless of
+** the value of the dataOnly flag.
 */
 static int full_fsync(int fd, int fullSync, int dataOnly){
   int rc;
@@ -24618,6 +26031,7 @@ static int full_fsync(int fd, int fullSync, int dataOnly){
   UNUSED_PARAMETER(dataOnly);
 #else
   UNUSED_PARAMETER(fullSync);
+  UNUSED_PARAMETER(dataOnly);
 #endif
 
   /* Record the number of times that we do a normal fsync() and 
@@ -24636,7 +26050,7 @@ static int full_fsync(int fd, int fullSync, int dataOnly){
   rc = SQLITE_OK;
 #elif HAVE_FULLFSYNC
   if( fullSync ){
-    rc = fcntl(fd, F_FULLFSYNC, 0);
+    rc = osFcntl(fd, F_FULLFSYNC, 0);
   }else{
     rc = 1;
   }
@@ -24650,17 +26064,18 @@ static int full_fsync(int fd, int fullSync, int dataOnly){
   */
   if( rc ) rc = fsync(fd);
 
+#elif defined(__APPLE__)
+  /* fdatasync() on HFS+ doesn't yet flush the file size if it changed correctly
+  ** so currently we default to the macro that redefines fdatasync to fsync
+  */
+  rc = fsync(fd);
 #else 
-  if( dataOnly ){
-    rc = fdatasync(fd);
+  rc = fdatasync(fd);
 #if OS_VXWORKS
-    if( rc==-1 && errno==ENOTSUP ){
-      rc = fsync(fd);
-    }
-#endif
-  }else{
+  if( rc==-1 && errno==ENOTSUP ){
     rc = fsync(fd);
   }
+#endif /* OS_VXWORKS */
 #endif /* ifdef SQLITE_NO_SYNC elif HAVE_FULLFSYNC */
 
   if( OS_VXWORKS && rc!= -1 ){
@@ -24669,6 +26084,47 @@ static int full_fsync(int fd, int fullSync, int dataOnly){
   return rc;
 }
 
+/*
+** Open a file descriptor to the directory containing file zFilename.
+** If successful, *pFd is set to the opened file descriptor and
+** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM
+** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined
+** value.
+**
+** The directory file descriptor is used for only one thing - to
+** fsync() a directory to make sure file creation and deletion events
+** are flushed to disk.  Such fsyncs are not needed on newer
+** journaling filesystems, but are required on older filesystems.
+**
+** This routine can be overridden using the xSetSysCall interface.
+** The ability to override this routine was added in support of the
+** chromium sandbox.  Opening a directory is a security risk (we are
+** told) so making it overrideable allows the chromium sandbox to
+** replace this routine with a harmless no-op.  To make this routine
+** a no-op, replace it with a stub that returns SQLITE_OK but leaves
+** *pFd set to a negative number.
+**
+** If SQLITE_OK is returned, the caller is responsible for closing
+** the file descriptor *pFd using close().
+*/
+static int openDirectory(const char *zFilename, int *pFd){
+  int ii;
+  int fd = -1;
+  char zDirname[MAX_PATHNAME+1];
+
+  sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename);
+  for(ii=(int)strlen(zDirname); ii>1 && zDirname[ii]!='/'; ii--);
+  if( ii>0 ){
+    zDirname[ii] = '\0';
+    fd = robust_open(zDirname, O_RDONLY|O_BINARY, 0);
+    if( fd>=0 ){
+      OSTRACE(("OPENDIR %-3d %s\n", fd, zDirname));
+    }
+  }
+  *pFd = fd;
+  return (fd>=0?SQLITE_OK:unixLogError(SQLITE_CANTOPEN_BKPT, "open", zDirname));
+}
+
 /*
 ** Make sure all writes to a particular file are committed to disk.
 **
@@ -24702,40 +26158,30 @@ static int unixSync(sqlite3_file *id, int flags){
   SimulateDiskfullError( return SQLITE_FULL );
 
   assert( pFile );
-  OSTRACE2("SYNC    %-3d\n", pFile->h);
+  OSTRACE(("SYNC    %-3d\n", pFile->h));
   rc = full_fsync(pFile->h, isFullsync, isDataOnly);
   SimulateIOError( rc=1 );
   if( rc ){
     pFile->lastErrno = errno;
-    return SQLITE_IOERR_FSYNC;
+    return unixLogError(SQLITE_IOERR_FSYNC, "full_fsync", pFile->zPath);
   }
-  if( pFile->dirfd>=0 ){
-    int err;
-    OSTRACE4("DIRSYNC %-3d (have_fullfsync=%d fullsync=%d)\n", pFile->dirfd,
-            HAVE_FULLFSYNC, isFullsync);
-#ifndef SQLITE_DISABLE_DIRSYNC
-    /* The directory sync is only attempted if full_fsync is
-    ** turned off or unavailable.  If a full_fsync occurred above,
-    ** then the directory sync is superfluous.
-    */
-    if( (!HAVE_FULLFSYNC || !isFullsync) && full_fsync(pFile->dirfd,0,0) ){
-       /*
-       ** We have received multiple reports of fsync() returning
-       ** errors when applied to directories on certain file systems.
-       ** A failed directory sync is not a big deal.  So it seems
-       ** better to ignore the error.  Ticket #1657
-       */
-       /* pFile->lastErrno = errno; */
-       /* return SQLITE_IOERR; */
-    }
-#endif
-    err = close(pFile->dirfd); /* Only need to sync once, so close the */
-    if( err==0 ){              /* directory when we are done */
-      pFile->dirfd = -1;
-    }else{
-      pFile->lastErrno = errno;
-      rc = SQLITE_IOERR_DIR_CLOSE;
+
+  /* Also fsync the directory containing the file if the DIRSYNC flag
+  ** is set.  This is a one-time occurrance.  Many systems (examples: AIX)
+  ** are unable to fsync a directory, so ignore errors on the fsync.
+  */
+  if( pFile->ctrlFlags & UNIXFILE_DIRSYNC ){
+    int dirfd;
+    OSTRACE(("DIRSYNC %s (have_fullfsync=%d fullsync=%d)\n", pFile->zPath,
+            HAVE_FULLFSYNC, isFullsync));
+    rc = osOpenDirectory(pFile->zPath, &dirfd);
+    if( rc==SQLITE_OK && dirfd>=0 ){
+      full_fsync(dirfd, 0, 0);
+      robust_close(pFile, dirfd, __LINE__);
+    }else if( rc==SQLITE_CANTOPEN ){
+      rc = SQLITE_OK;
     }
+    pFile->ctrlFlags &= ~UNIXFILE_DIRSYNC;
   }
   return rc;
 }
@@ -24744,14 +26190,38 @@ static int unixSync(sqlite3_file *id, int flags){
 ** Truncate an open file to a specified size
 */
 static int unixTruncate(sqlite3_file *id, i64 nByte){
+  unixFile *pFile = (unixFile *)id;
   int rc;
-  assert( id );
+  assert( pFile );
   SimulateIOError( return SQLITE_IOERR_TRUNCATE );
-  rc = ftruncate(((unixFile*)id)->h, (off_t)nByte);
+
+  /* If the user has configured a chunk-size for this file, truncate the
+  ** file so that it consists of an integer number of chunks (i.e. the
+  ** actual file size after the operation may be larger than the requested
+  ** size).
+  */
+  if( pFile->szChunk>0 ){
+    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
+  }
+
+  rc = robust_ftruncate(pFile->h, (off_t)nByte);
   if( rc ){
-    ((unixFile*)id)->lastErrno = errno;
-    return SQLITE_IOERR_TRUNCATE;
+    pFile->lastErrno = errno;
+    return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
   }else{
+#ifdef SQLITE_DEBUG
+    /* If we are doing a normal write to a database file (as opposed to
+    ** doing a hot-journal rollback or a write to some file other than a
+    ** normal database file) and we truncate the file to zero length,
+    ** that effectively updates the change counter.  This might happen
+    ** when restoring a database using the backup API from a zero-length
+    ** source.
+    */
+    if( pFile->inNormalWrite && nByte==0 ){
+      pFile->transCntrChng = 1;
+    }
+#endif
+
     return SQLITE_OK;
   }
 }
@@ -24763,7 +26233,7 @@ static int unixFileSize(sqlite3_file *id, i64 *pSize){
   int rc;
   struct stat buf;
   assert( id );
-  rc = fstat(((unixFile*)id)->h, &buf);
+  rc = osFstat(((unixFile*)id)->h, &buf);
   SimulateIOError( rc=1 );
   if( rc!=0 ){
     ((unixFile*)id)->lastErrno = errno;
@@ -24771,7 +26241,7 @@ static int unixFileSize(sqlite3_file *id, i64 *pSize){
   }
   *pSize = buf.st_size;
 
-  /* When opening a zero-size database, the findLockInfo() procedure
+  /* When opening a zero-size database, the findInodeInfo() procedure
   ** writes a single byte into that file in order to work around a bug
   ** in the OS-X msdos filesystem.  In order to avoid problems with upper
   ** layers, we need to report this file size as zero even though it is
@@ -24791,21 +26261,112 @@ static int unixFileSize(sqlite3_file *id, i64 *pSize){
 static int proxyFileControl(sqlite3_file*,int,void*);
 #endif
 
+/* 
+** This function is called to handle the SQLITE_FCNTL_SIZE_HINT 
+** file-control operation.  Enlarge the database to nBytes in size
+** (rounded up to the next chunk-size).  If the database is already
+** nBytes or larger, this routine is a no-op.
+*/
+static int fcntlSizeHint(unixFile *pFile, i64 nByte){
+  if( pFile->szChunk>0 ){
+    i64 nSize;                    /* Required file size */
+    struct stat buf;              /* Used to hold return values of fstat() */
+   
+    if( osFstat(pFile->h, &buf) ) return SQLITE_IOERR_FSTAT;
+
+    nSize = ((nByte+pFile->szChunk-1) / pFile->szChunk) * pFile->szChunk;
+    if( nSize>(i64)buf.st_size ){
+
+#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
+      /* The code below is handling the return value of osFallocate() 
+      ** correctly. posix_fallocate() is defined to "returns zero on success, 
+      ** or an error number on  failure". See the manpage for details. */
+      int err;
+      do{
+        err = osFallocate(pFile->h, buf.st_size, nSize-buf.st_size);
+      }while( err==EINTR );
+      if( err ) return SQLITE_IOERR_WRITE;
+#else
+      /* If the OS does not have posix_fallocate(), fake it. First use
+      ** ftruncate() to set the file size, then write a single byte to
+      ** the last byte in each block within the extended region. This
+      ** is the same technique used by glibc to implement posix_fallocate()
+      ** on systems that do not have a real fallocate() system call.
+      */
+      int nBlk = buf.st_blksize;  /* File-system block size */
+      i64 iWrite;                 /* Next offset to write to */
+
+      if( robust_ftruncate(pFile->h, nSize) ){
+        pFile->lastErrno = errno;
+        return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
+      }
+      iWrite = ((buf.st_size + 2*nBlk - 1)/nBlk)*nBlk-1;
+      while( iWrite<nSize ){
+        int nWrite = seekAndWrite(pFile, iWrite, "", 1);
+        if( nWrite!=1 ) return SQLITE_IOERR_WRITE;
+        iWrite += nBlk;
+      }
+#endif
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** If *pArg is inititially negative then this is a query.  Set *pArg to
+** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
+**
+** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
+*/
+static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){
+  if( *pArg<0 ){
+    *pArg = (pFile->ctrlFlags & mask)!=0;
+  }else if( (*pArg)==0 ){
+    pFile->ctrlFlags &= ~mask;
+  }else{
+    pFile->ctrlFlags |= mask;
+  }
+}
 
 /*
 ** Information and control of an open file handle.
 */
 static int unixFileControl(sqlite3_file *id, int op, void *pArg){
+  unixFile *pFile = (unixFile*)id;
   switch( op ){
     case SQLITE_FCNTL_LOCKSTATE: {
-      *(int*)pArg = ((unixFile*)id)->locktype;
+      *(int*)pArg = pFile->eFileLock;
       return SQLITE_OK;
     }
     case SQLITE_LAST_ERRNO: {
-      *(int*)pArg = ((unixFile*)id)->lastErrno;
+      *(int*)pArg = pFile->lastErrno;
       return SQLITE_OK;
     }
-#ifndef NDEBUG
+    case SQLITE_FCNTL_CHUNK_SIZE: {
+      pFile->szChunk = *(int *)pArg;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SIZE_HINT: {
+      int rc;
+      SimulateIOErrorBenign(1);
+      rc = fcntlSizeHint(pFile, *(i64 *)pArg);
+      SimulateIOErrorBenign(0);
+      return rc;
+    }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      unixModeBit(pFile, UNIXFILE_PERSIST_WAL, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
+      unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_VFSNAME: {
+      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
+      return SQLITE_OK;
+    }
+#ifdef SQLITE_DEBUG
     /* The pager calls this method to signal that it has done
     ** a rollback and that the database is therefore unchanged and
     ** it hence it is OK for the transaction change counter to be
@@ -24823,7 +26384,7 @@ static int unixFileControl(sqlite3_file *id, int op, void *pArg){
     }
 #endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */
   }
-  return SQLITE_ERROR;
+  return SQLITE_NOTFOUND;
 }
 
 /*
@@ -24836,19 +26397,683 @@ static int unixFileControl(sqlite3_file *id, int op, void *pArg){
 ** a database and its journal file) that the sector size will be the
 ** same for both.
 */
-static int unixSectorSize(sqlite3_file *NotUsed){
-  UNUSED_PARAMETER(NotUsed);
+static int unixSectorSize(sqlite3_file *pFile){
+  (void)pFile;
   return SQLITE_DEFAULT_SECTOR_SIZE;
 }
 
 /*
-** Return the device characteristics for the file. This is always 0 for unix.
+** Return the device characteristics for the file.
+**
+** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default.
+** However, that choice is contraversial since technically the underlying
+** file system does not always provide powersafe overwrites.  (In other
+** words, after a power-loss event, parts of the file that were never
+** written might end up being altered.)  However, non-PSOW behavior is very,
+** very rare.  And asserting PSOW makes a large reduction in the amount
+** of required I/O for journaling, since a lot of padding is eliminated.
+**  Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control
+** available to turn it off and URI query parameter available to turn it off.
 */
-static int unixDeviceCharacteristics(sqlite3_file *NotUsed){
-  UNUSED_PARAMETER(NotUsed);
-  return 0;
+static int unixDeviceCharacteristics(sqlite3_file *id){
+  unixFile *p = (unixFile*)id;
+  if( p->ctrlFlags & UNIXFILE_PSOW ){
+    return SQLITE_IOCAP_POWERSAFE_OVERWRITE;
+  }else{
+    return 0;
+  }
 }
 
+#ifndef SQLITE_OMIT_WAL
+
+
+/*
+** Object used to represent an shared memory buffer.  
+**
+** When multiple threads all reference the same wal-index, each thread
+** has its own unixShm object, but they all point to a single instance
+** of this unixShmNode object.  In other words, each wal-index is opened
+** only once per process.
+**
+** Each unixShmNode object is connected to a single unixInodeInfo object.
+** We could coalesce this object into unixInodeInfo, but that would mean
+** every open file that does not use shared memory (in other words, most
+** open files) would have to carry around this extra information.  So
+** the unixInodeInfo object contains a pointer to this unixShmNode object
+** and the unixShmNode object is created only when needed.
+**
+** unixMutexHeld() must be true when creating or destroying
+** this object or while reading or writing the following fields:
+**
+**      nRef
+**
+** The following fields are read-only after the object is created:
+** 
+**      fid
+**      zFilename
+**
+** Either unixShmNode.mutex must be held or unixShmNode.nRef==0 and
+** unixMutexHeld() is true when reading or writing any other field
+** in this structure.
+*/
+struct unixShmNode {
+  unixInodeInfo *pInode;     /* unixInodeInfo that owns this SHM node */
+  sqlite3_mutex *mutex;      /* Mutex to access this object */
+  char *zFilename;           /* Name of the mmapped file */
+  int h;                     /* Open file descriptor */
+  int szRegion;              /* Size of shared-memory regions */
+  u16 nRegion;               /* Size of array apRegion */
+  u8 isReadonly;             /* True if read-only */
+  char **apRegion;           /* Array of mapped shared-memory regions */
+  int nRef;                  /* Number of unixShm objects pointing to this */
+  unixShm *pFirst;           /* All unixShm objects pointing to this */
+#ifdef SQLITE_DEBUG
+  u8 exclMask;               /* Mask of exclusive locks held */
+  u8 sharedMask;             /* Mask of shared locks held */
+  u8 nextShmId;              /* Next available unixShm.id value */
+#endif
+};
+
+/*
+** Structure used internally by this VFS to record the state of an
+** open shared memory connection.
+**
+** The following fields are initialized when this object is created and
+** are read-only thereafter:
+**
+**    unixShm.pFile
+**    unixShm.id
+**
+** All other fields are read/write.  The unixShm.pFile->mutex must be held
+** while accessing any read/write fields.
+*/
+struct unixShm {
+  unixShmNode *pShmNode;     /* The underlying unixShmNode object */
+  unixShm *pNext;            /* Next unixShm with the same unixShmNode */
+  u8 hasMutex;               /* True if holding the unixShmNode mutex */
+  u8 id;                     /* Id of this connection within its unixShmNode */
+  u16 sharedMask;            /* Mask of shared locks held */
+  u16 exclMask;              /* Mask of exclusive locks held */
+};
+
+/*
+** Constants used for locking
+*/
+#define UNIX_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)         /* first lock byte */
+#define UNIX_SHM_DMS    (UNIX_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */
+
+/*
+** Apply posix advisory locks for all bytes from ofst through ofst+n-1.
+**
+** Locks block if the mask is exactly UNIX_SHM_C and are non-blocking
+** otherwise.
+*/
+static int unixShmSystemLock(
+  unixShmNode *pShmNode, /* Apply locks to this open shared-memory segment */
+  int lockType,          /* F_UNLCK, F_RDLCK, or F_WRLCK */
+  int ofst,              /* First byte of the locking range */
+  int n                  /* Number of bytes to lock */
+){
+  struct flock f;       /* The posix advisory locking structure */
+  int rc = SQLITE_OK;   /* Result code form fcntl() */
+
+  /* Access to the unixShmNode object is serialized by the caller */
+  assert( sqlite3_mutex_held(pShmNode->mutex) || pShmNode->nRef==0 );
+
+  /* Shared locks never span more than one byte */
+  assert( n==1 || lockType!=F_RDLCK );
+
+  /* Locks are within range */
+  assert( n>=1 && n<SQLITE_SHM_NLOCK );
+
+  if( pShmNode->h>=0 ){
+    /* Initialize the locking parameters */
+    memset(&f, 0, sizeof(f));
+    f.l_type = lockType;
+    f.l_whence = SEEK_SET;
+    f.l_start = ofst;
+    f.l_len = n;
+
+    rc = osFcntl(pShmNode->h, F_SETLK, &f);
+    rc = (rc!=(-1)) ? SQLITE_OK : SQLITE_BUSY;
+  }
+
+  /* Update the global lock state and do debug tracing */
+#ifdef SQLITE_DEBUG
+  { u16 mask;
+  OSTRACE(("SHM-LOCK "));
+  mask = (1<<(ofst+n)) - (1<<ofst);
+  if( rc==SQLITE_OK ){
+    if( lockType==F_UNLCK ){
+      OSTRACE(("unlock %d ok", ofst));
+      pShmNode->exclMask &= ~mask;
+      pShmNode->sharedMask &= ~mask;
+    }else if( lockType==F_RDLCK ){
+      OSTRACE(("read-lock %d ok", ofst));
+      pShmNode->exclMask &= ~mask;
+      pShmNode->sharedMask |= mask;
+    }else{
+      assert( lockType==F_WRLCK );
+      OSTRACE(("write-lock %d ok", ofst));
+      pShmNode->exclMask |= mask;
+      pShmNode->sharedMask &= ~mask;
+    }
+  }else{
+    if( lockType==F_UNLCK ){
+      OSTRACE(("unlock %d failed", ofst));
+    }else if( lockType==F_RDLCK ){
+      OSTRACE(("read-lock failed"));
+    }else{
+      assert( lockType==F_WRLCK );
+      OSTRACE(("write-lock %d failed", ofst));
+    }
+  }
+  OSTRACE((" - afterwards %03x,%03x\n",
+           pShmNode->sharedMask, pShmNode->exclMask));
+  }
+#endif
+
+  return rc;        
+}
+
+
+/*
+** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0.
+**
+** This is not a VFS shared-memory method; it is a utility function called
+** by VFS shared-memory methods.
+*/
+static void unixShmPurge(unixFile *pFd){
+  unixShmNode *p = pFd->pInode->pShmNode;
+  assert( unixMutexHeld() );
+  if( p && p->nRef==0 ){
+    int i;
+    assert( p->pInode==pFd->pInode );
+    sqlite3_mutex_free(p->mutex);
+    for(i=0; i<p->nRegion; i++){
+      if( p->h>=0 ){
+        munmap(p->apRegion[i], p->szRegion);
+      }else{
+        sqlite3_free(p->apRegion[i]);
+      }
+    }
+    sqlite3_free(p->apRegion);
+    if( p->h>=0 ){
+      robust_close(pFd, p->h, __LINE__);
+      p->h = -1;
+    }
+    p->pInode->pShmNode = 0;
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Open a shared-memory area associated with open database file pDbFd.  
+** This particular implementation uses mmapped files.
+**
+** The file used to implement shared-memory is in the same directory
+** as the open database file and has the same name as the open database
+** file with the "-shm" suffix added.  For example, if the database file
+** is "/home/user1/config.db" then the file that is created and mmapped
+** for shared memory will be called "/home/user1/config.db-shm".  
+**
+** Another approach to is to use files in /dev/shm or /dev/tmp or an
+** some other tmpfs mount. But if a file in a different directory
+** from the database file is used, then differing access permissions
+** or a chroot() might cause two different processes on the same
+** database to end up using different files for shared memory - 
+** meaning that their memory would not really be shared - resulting
+** in database corruption.  Nevertheless, this tmpfs file usage
+** can be enabled at compile-time using -DSQLITE_SHM_DIRECTORY="/dev/shm"
+** or the equivalent.  The use of the SQLITE_SHM_DIRECTORY compile-time
+** option results in an incompatible build of SQLite;  builds of SQLite
+** that with differing SQLITE_SHM_DIRECTORY settings attempt to use the
+** same database file at the same time, database corruption will likely
+** result. The SQLITE_SHM_DIRECTORY compile-time option is considered
+** "unsupported" and may go away in a future SQLite release.
+**
+** When opening a new shared-memory file, if no other instances of that
+** file are currently open, in this process or in other processes, then
+** the file must be truncated to zero length or have its header cleared.
+**
+** If the original database file (pDbFd) is using the "unix-excl" VFS
+** that means that an exclusive lock is held on the database file and
+** that no other processes are able to read or write the database.  In
+** that case, we do not really need shared memory.  No shared memory
+** file is created.  The shared memory will be simulated with heap memory.
+*/
+static int unixOpenSharedMemory(unixFile *pDbFd){
+  struct unixShm *p = 0;          /* The connection to be opened */
+  struct unixShmNode *pShmNode;   /* The underlying mmapped file */
+  int rc;                         /* Result code */
+  unixInodeInfo *pInode;          /* The inode of fd */
+  char *zShmFilename;             /* Name of the file used for SHM */
+  int nShmFilename;               /* Size of the SHM filename in bytes */
+
+  /* Allocate space for the new unixShm object. */
+  p = sqlite3_malloc( sizeof(*p) );
+  if( p==0 ) return SQLITE_NOMEM;
+  memset(p, 0, sizeof(*p));
+  assert( pDbFd->pShm==0 );
+
+  /* Check to see if a unixShmNode object already exists. Reuse an existing
+  ** one if present. Create a new one if necessary.
+  */
+  unixEnterMutex();
+  pInode = pDbFd->pInode;
+  pShmNode = pInode->pShmNode;
+  if( pShmNode==0 ){
+    struct stat sStat;                 /* fstat() info for database file */
+
+    /* Call fstat() to figure out the permissions on the database file. If
+    ** a new *-shm file is created, an attempt will be made to create it
+    ** with the same permissions.
+    */
+    if( osFstat(pDbFd->h, &sStat) && pInode->bProcessLock==0 ){
+      rc = SQLITE_IOERR_FSTAT;
+      goto shm_open_err;
+    }
+
+#ifdef SQLITE_SHM_DIRECTORY
+    nShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31;
+#else
+    nShmFilename = 6 + (int)strlen(pDbFd->zPath);
+#endif
+    pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nShmFilename );
+    if( pShmNode==0 ){
+      rc = SQLITE_NOMEM;
+      goto shm_open_err;
+    }
+    memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename);
+    zShmFilename = pShmNode->zFilename = (char*)&pShmNode[1];
+#ifdef SQLITE_SHM_DIRECTORY
+    sqlite3_snprintf(nShmFilename, zShmFilename, 
+                     SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x",
+                     (u32)sStat.st_ino, (u32)sStat.st_dev);
+#else
+    sqlite3_snprintf(nShmFilename, zShmFilename, "%s-shm", pDbFd->zPath);
+    sqlite3FileSuffix3(pDbFd->zPath, zShmFilename);
+#endif
+    pShmNode->h = -1;
+    pDbFd->pInode->pShmNode = pShmNode;
+    pShmNode->pInode = pDbFd->pInode;
+    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+    if( pShmNode->mutex==0 ){
+      rc = SQLITE_NOMEM;
+      goto shm_open_err;
+    }
+
+    if( pInode->bProcessLock==0 ){
+      int openFlags = O_RDWR | O_CREAT;
+      if( sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){
+        openFlags = O_RDONLY;
+        pShmNode->isReadonly = 1;
+      }
+      pShmNode->h = robust_open(zShmFilename, openFlags, (sStat.st_mode&0777));
+      if( pShmNode->h<0 ){
+        rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShmFilename);
+        goto shm_open_err;
+      }
+
+      /* If this process is running as root, make sure that the SHM file
+      ** is owned by the same user that owns the original database.  Otherwise,
+      ** the original owner will not be able to connect.
+      */
+      osFchown(pShmNode->h, sStat.st_uid, sStat.st_gid);
+  
+      /* Check to see if another process is holding the dead-man switch.
+      ** If not, truncate the file to zero length. 
+      */
+      rc = SQLITE_OK;
+      if( unixShmSystemLock(pShmNode, F_WRLCK, UNIX_SHM_DMS, 1)==SQLITE_OK ){
+        if( robust_ftruncate(pShmNode->h, 0) ){
+          rc = unixLogError(SQLITE_IOERR_SHMOPEN, "ftruncate", zShmFilename);
+        }
+      }
+      if( rc==SQLITE_OK ){
+        rc = unixShmSystemLock(pShmNode, F_RDLCK, UNIX_SHM_DMS, 1);
+      }
+      if( rc ) goto shm_open_err;
+    }
+  }
+
+  /* Make the new connection a child of the unixShmNode */
+  p->pShmNode = pShmNode;
+#ifdef SQLITE_DEBUG
+  p->id = pShmNode->nextShmId++;
+#endif
+  pShmNode->nRef++;
+  pDbFd->pShm = p;
+  unixLeaveMutex();
+
+  /* The reference count on pShmNode has already been incremented under
+  ** the cover of the unixEnterMutex() mutex and the pointer from the
+  ** new (struct unixShm) object to the pShmNode has been set. All that is
+  ** left to do is to link the new object into the linked list starting
+  ** at pShmNode->pFirst. This must be done while holding the pShmNode->mutex 
+  ** mutex.
+  */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  p->pNext = pShmNode->pFirst;
+  pShmNode->pFirst = p;
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return SQLITE_OK;
+
+  /* Jump here on any error */
+shm_open_err:
+  unixShmPurge(pDbFd);       /* This call frees pShmNode if required */
+  sqlite3_free(p);
+  unixLeaveMutex();
+  return rc;
+}
+
+/*
+** This function is called to obtain a pointer to region iRegion of the 
+** shared-memory associated with the database file fd. Shared-memory regions 
+** are numbered starting from zero. Each shared-memory region is szRegion 
+** bytes in size.
+**
+** If an error occurs, an error code is returned and *pp is set to NULL.
+**
+** Otherwise, if the bExtend parameter is 0 and the requested shared-memory
+** region has not been allocated (by any client, including one running in a
+** separate process), then *pp is set to NULL and SQLITE_OK returned. If 
+** bExtend is non-zero and the requested shared-memory region has not yet 
+** been allocated, it is allocated by this function.
+**
+** If the shared-memory region has already been allocated or is allocated by
+** this call as described above, then it is mapped into this processes 
+** address space (if it is not already), *pp is set to point to the mapped 
+** memory and SQLITE_OK returned.
+*/
+static int unixShmMap(
+  sqlite3_file *fd,               /* Handle open on database file */
+  int iRegion,                    /* Region to retrieve */
+  int szRegion,                   /* Size of regions */
+  int bExtend,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Mapped memory */
+){
+  unixFile *pDbFd = (unixFile*)fd;
+  unixShm *p;
+  unixShmNode *pShmNode;
+  int rc = SQLITE_OK;
+
+  /* If the shared-memory file has not yet been opened, open it now. */
+  if( pDbFd->pShm==0 ){
+    rc = unixOpenSharedMemory(pDbFd);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  p = pDbFd->pShm;
+  pShmNode = p->pShmNode;
+  sqlite3_mutex_enter(pShmNode->mutex);
+  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
+  assert( pShmNode->pInode==pDbFd->pInode );
+  assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 );
+  assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 );
+
+  if( pShmNode->nRegion<=iRegion ){
+    char **apNew;                      /* New apRegion[] array */
+    int nByte = (iRegion+1)*szRegion;  /* Minimum required file size */
+    struct stat sStat;                 /* Used by fstat() */
+
+    pShmNode->szRegion = szRegion;
+
+    if( pShmNode->h>=0 ){
+      /* The requested region is not mapped into this processes address space.
+      ** Check to see if it has been allocated (i.e. if the wal-index file is
+      ** large enough to contain the requested region).
+      */
+      if( osFstat(pShmNode->h, &sStat) ){
+        rc = SQLITE_IOERR_SHMSIZE;
+        goto shmpage_out;
+      }
+  
+      if( sStat.st_size<nByte ){
+        /* The requested memory region does not exist. If bExtend is set to
+        ** false, exit early. *pp will be set to NULL and SQLITE_OK returned.
+        **
+        ** Alternatively, if bExtend is true, use ftruncate() to allocate
+        ** the requested memory region.
+        */
+        if( !bExtend ) goto shmpage_out;
+        if( robust_ftruncate(pShmNode->h, nByte) ){
+          rc = unixLogError(SQLITE_IOERR_SHMSIZE, "ftruncate",
+                            pShmNode->zFilename);
+          goto shmpage_out;
+        }
+      }
+    }
+
+    /* Map the requested memory region into this processes address space. */
+    apNew = (char **)sqlite3_realloc(
+        pShmNode->apRegion, (iRegion+1)*sizeof(char *)
+    );
+    if( !apNew ){
+      rc = SQLITE_IOERR_NOMEM;
+      goto shmpage_out;
+    }
+    pShmNode->apRegion = apNew;
+    while(pShmNode->nRegion<=iRegion){
+      void *pMem;
+      if( pShmNode->h>=0 ){
+        pMem = mmap(0, szRegion,
+            pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE, 
+            MAP_SHARED, pShmNode->h, pShmNode->nRegion*szRegion
+        );
+        if( pMem==MAP_FAILED ){
+          rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename);
+          goto shmpage_out;
+        }
+      }else{
+        pMem = sqlite3_malloc(szRegion);
+        if( pMem==0 ){
+          rc = SQLITE_NOMEM;
+          goto shmpage_out;
+        }
+        memset(pMem, 0, szRegion);
+      }
+      pShmNode->apRegion[pShmNode->nRegion] = pMem;
+      pShmNode->nRegion++;
+    }
+  }
+
+shmpage_out:
+  if( pShmNode->nRegion>iRegion ){
+    *pp = pShmNode->apRegion[iRegion];
+  }else{
+    *pp = 0;
+  }
+  if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY;
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return rc;
+}
+
+/*
+** Change the lock state for a shared-memory segment.
+**
+** Note that the relationship between SHAREd and EXCLUSIVE locks is a little
+** different here than in posix.  In xShmLock(), one can go from unlocked
+** to shared and back or from unlocked to exclusive and back.  But one may
+** not go from shared to exclusive or from exclusive to shared.
+*/
+static int unixShmLock(
+  sqlite3_file *fd,          /* Database file holding the shared memory */
+  int ofst,                  /* First lock to acquire or release */
+  int n,                     /* Number of locks to acquire or release */
+  int flags                  /* What to do with the lock */
+){
+  unixFile *pDbFd = (unixFile*)fd;      /* Connection holding shared memory */
+  unixShm *p = pDbFd->pShm;             /* The shared memory being locked */
+  unixShm *pX;                          /* For looping over all siblings */
+  unixShmNode *pShmNode = p->pShmNode;  /* The underlying file iNode */
+  int rc = SQLITE_OK;                   /* Result code */
+  u16 mask;                             /* Mask of locks to take or release */
+
+  assert( pShmNode==pDbFd->pInode->pShmNode );
+  assert( pShmNode->pInode==pDbFd->pInode );
+  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
+  assert( n>=1 );
+  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
+  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );
+  assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 );
+  assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 );
+
+  mask = (1<<(ofst+n)) - (1<<ofst);
+  assert( n>1 || mask==(1<<ofst) );
+  sqlite3_mutex_enter(pShmNode->mutex);
+  if( flags & SQLITE_SHM_UNLOCK ){
+    u16 allMask = 0; /* Mask of locks held by siblings */
+
+    /* See if any siblings hold this same lock */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( pX==p ) continue;
+      assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
+      allMask |= pX->sharedMask;
+    }
+
+    /* Unlock the system-level locks */
+    if( (mask & allMask)==0 ){
+      rc = unixShmSystemLock(pShmNode, F_UNLCK, ofst+UNIX_SHM_BASE, n);
+    }else{
+      rc = SQLITE_OK;
+    }
+
+    /* Undo the local locks */
+    if( rc==SQLITE_OK ){
+      p->exclMask &= ~mask;
+      p->sharedMask &= ~mask;
+    } 
+  }else if( flags & SQLITE_SHM_SHARED ){
+    u16 allShared = 0;  /* Union of locks held by connections other than "p" */
+
+    /* Find out which shared locks are already held by sibling connections.
+    ** If any sibling already holds an exclusive lock, go ahead and return
+    ** SQLITE_BUSY.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+      allShared |= pX->sharedMask;
+    }
+
+    /* Get shared locks at the system level, if necessary */
+    if( rc==SQLITE_OK ){
+      if( (allShared & mask)==0 ){
+        rc = unixShmSystemLock(pShmNode, F_RDLCK, ofst+UNIX_SHM_BASE, n);
+      }else{
+        rc = SQLITE_OK;
+      }
+    }
+
+    /* Get the local shared locks */
+    if( rc==SQLITE_OK ){
+      p->sharedMask |= mask;
+    }
+  }else{
+    /* Make sure no sibling connections hold locks that will block this
+    ** lock.  If any do, return SQLITE_BUSY right away.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 || (pX->sharedMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+    }
+  
+    /* Get the exclusive locks at the system level.  Then if successful
+    ** also mark the local connection as being locked.
+    */
+    if( rc==SQLITE_OK ){
+      rc = unixShmSystemLock(pShmNode, F_WRLCK, ofst+UNIX_SHM_BASE, n);
+      if( rc==SQLITE_OK ){
+        assert( (p->sharedMask & mask)==0 );
+        p->exclMask |= mask;
+      }
+    }
+  }
+  sqlite3_mutex_leave(pShmNode->mutex);
+  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x\n",
+           p->id, getpid(), p->sharedMask, p->exclMask));
+  return rc;
+}
+
+/*
+** Implement a memory barrier or memory fence on shared memory.  
+**
+** All loads and stores begun before the barrier must complete before
+** any load or store begun after the barrier.
+*/
+static void unixShmBarrier(
+  sqlite3_file *fd                /* Database file holding the shared memory */
+){
+  UNUSED_PARAMETER(fd);
+  unixEnterMutex();
+  unixLeaveMutex();
+}
+
+/*
+** Close a connection to shared-memory.  Delete the underlying 
+** storage if deleteFlag is true.
+**
+** If there is no shared memory associated with the connection then this
+** routine is a harmless no-op.
+*/
+static int unixShmUnmap(
+  sqlite3_file *fd,               /* The underlying database file */
+  int deleteFlag                  /* Delete shared-memory if true */
+){
+  unixShm *p;                     /* The connection to be closed */
+  unixShmNode *pShmNode;          /* The underlying shared-memory file */
+  unixShm **pp;                   /* For looping over sibling connections */
+  unixFile *pDbFd;                /* The underlying database file */
+
+  pDbFd = (unixFile*)fd;
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_OK;
+  pShmNode = p->pShmNode;
+
+  assert( pShmNode==pDbFd->pInode->pShmNode );
+  assert( pShmNode->pInode==pDbFd->pInode );
+
+  /* Remove connection p from the set of connections associated
+  ** with pShmNode */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
+  *pp = p->pNext;
+
+  /* Free the connection p */
+  sqlite3_free(p);
+  pDbFd->pShm = 0;
+  sqlite3_mutex_leave(pShmNode->mutex);
+
+  /* If pShmNode->nRef has reached 0, then close the underlying
+  ** shared-memory file, too */
+  unixEnterMutex();
+  assert( pShmNode->nRef>0 );
+  pShmNode->nRef--;
+  if( pShmNode->nRef==0 ){
+    if( deleteFlag && pShmNode->h>=0 ) osUnlink(pShmNode->zFilename);
+    unixShmPurge(pDbFd);
+  }
+  unixLeaveMutex();
+
+  return SQLITE_OK;
+}
+
+
+#else
+# define unixShmMap     0
+# define unixShmLock    0
+# define unixShmBarrier 0
+# define unixShmUnmap   0
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
 /*
 ** Here ends the implementation of all sqlite3_file methods.
 **
@@ -24872,7 +27097,7 @@ static int unixDeviceCharacteristics(sqlite3_file *NotUsed){
 **
 **    (1) The real finder-function named "FImpt()".
 **
-**    (2) A constant pointer to this functio named just "F".
+**    (2) A constant pointer to this function named just "F".
 **
 **
 ** A pointer to the F pointer is used as the pAppData value for VFS
@@ -24889,9 +27114,9 @@ static int unixDeviceCharacteristics(sqlite3_file *NotUsed){
 **   *  An I/O method finder function called FINDER that returns a pointer
 **      to the METHOD object in the previous bullet.
 */
-#define IOMETHODS(FINDER, METHOD, CLOSE, LOCK, UNLOCK, CKLOCK)               \
+#define IOMETHODS(FINDER, METHOD, VERSION, CLOSE, LOCK, UNLOCK, CKLOCK)      \
 static const sqlite3_io_methods METHOD = {                                   \
-   1,                          /* iVersion */                                \
+   VERSION,                    /* iVersion */                                \
    CLOSE,                      /* xClose */                                  \
    unixRead,                   /* xRead */                                   \
    unixWrite,                  /* xWrite */                                  \
@@ -24903,13 +27128,17 @@ static const sqlite3_io_methods METHOD = {                                   \
    CKLOCK,                     /* xCheckReservedLock */                      \
    unixFileControl,            /* xFileControl */                            \
    unixSectorSize,             /* xSectorSize */                             \
-   unixDeviceCharacteristics   /* xDeviceCapabilities */                     \
+   unixDeviceCharacteristics,  /* xDeviceCapabilities */                     \
+   unixShmMap,                 /* xShmMap */                                 \
+   unixShmLock,                /* xShmLock */                                \
+   unixShmBarrier,             /* xShmBarrier */                             \
+   unixShmUnmap                /* xShmUnmap */                               \
 };                                                                           \
-static const sqlite3_io_methods *FINDER##Impl(const char *z, int h){         \
-  UNUSED_PARAMETER(z); UNUSED_PARAMETER(h);                                  \
+static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
+  UNUSED_PARAMETER(z); UNUSED_PARAMETER(p);                                  \
   return &METHOD;                                                            \
 }                                                                            \
-static const sqlite3_io_methods *(*const FINDER)(const char*,int)            \
+static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p)    \
     = FINDER##Impl;
 
 /*
@@ -24920,6 +27149,7 @@ static const sqlite3_io_methods *(*const FINDER)(const char*,int)            \
 IOMETHODS(
   posixIoFinder,            /* Finder function name */
   posixIoMethods,           /* sqlite3_io_methods object name */
+  2,                        /* shared memory is enabled */
   unixClose,                /* xClose method */
   unixLock,                 /* xLock method */
   unixUnlock,               /* xUnlock method */
@@ -24928,6 +27158,7 @@ IOMETHODS(
 IOMETHODS(
   nolockIoFinder,           /* Finder function name */
   nolockIoMethods,          /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
   nolockClose,              /* xClose method */
   nolockLock,               /* xLock method */
   nolockUnlock,             /* xUnlock method */
@@ -24936,16 +27167,18 @@ IOMETHODS(
 IOMETHODS(
   dotlockIoFinder,          /* Finder function name */
   dotlockIoMethods,         /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
   dotlockClose,             /* xClose method */
   dotlockLock,              /* xLock method */
   dotlockUnlock,            /* xUnlock method */
   dotlockCheckReservedLock  /* xCheckReservedLock method */
 )
 
-#if SQLITE_ENABLE_LOCKING_STYLE
+#if SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS
 IOMETHODS(
   flockIoFinder,            /* Finder function name */
   flockIoMethods,           /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
   flockClose,               /* xClose method */
   flockLock,                /* xLock method */
   flockUnlock,              /* xUnlock method */
@@ -24957,6 +27190,7 @@ IOMETHODS(
 IOMETHODS(
   semIoFinder,              /* Finder function name */
   semIoMethods,             /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
   semClose,                 /* xClose method */
   semLock,                  /* xLock method */
   semUnlock,                /* xUnlock method */
@@ -24968,6 +27202,7 @@ IOMETHODS(
 IOMETHODS(
   afpIoFinder,              /* Finder function name */
   afpIoMethods,             /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
   afpClose,                 /* xClose method */
   afpLock,                  /* xLock method */
   afpUnlock,                /* xUnlock method */
@@ -24992,6 +27227,7 @@ static int proxyCheckReservedLock(sqlite3_file*, int*);
 IOMETHODS(
   proxyIoFinder,            /* Finder function name */
   proxyIoMethods,           /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
   proxyClose,               /* xClose method */
   proxyLock,                /* xLock method */
   proxyUnlock,              /* xUnlock method */
@@ -24999,6 +27235,18 @@ IOMETHODS(
 )
 #endif
 
+/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+  nfsIoFinder,               /* Finder function name */
+  nfsIoMethods,              /* sqlite3_io_methods object name */
+  1,                         /* shared memory is disabled */
+  unixClose,                 /* xClose method */
+  unixLock,                  /* xLock method */
+  nfsUnlock,                 /* xUnlock method */
+  unixCheckReservedLock      /* xCheckReservedLock method */
+)
+#endif
 
 #if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
 /* 
@@ -25010,7 +27258,7 @@ IOMETHODS(
 */
 static const sqlite3_io_methods *autolockIoFinderImpl(
   const char *filePath,    /* name of the database file */
-  int fd                   /* file descriptor open on the database file */
+  unixFile *pNew           /* open file object for the database file */
 ){
   static const struct Mapping {
     const char *zFilesystem;              /* Filesystem type name */
@@ -25019,11 +27267,7 @@ static const sqlite3_io_methods *autolockIoFinderImpl(
     { "hfs",    &posixIoMethods },
     { "ufs",    &posixIoMethods },
     { "afpfs",  &afpIoMethods },
-#ifdef SQLITE_ENABLE_AFP_LOCKING_SMB
     { "smbfs",  &afpIoMethods },
-#else
-    { "smbfs",  &flockIoMethods },
-#endif
     { "webdav", &nolockIoMethods },
     { 0, 0 }
   };
@@ -25055,21 +27299,63 @@ static const sqlite3_io_methods *autolockIoFinderImpl(
   lockInfo.l_start = 0;
   lockInfo.l_whence = SEEK_SET;
   lockInfo.l_type = F_RDLCK;
-  if( fcntl(fd, F_GETLK, &lockInfo)!=-1 ) {
-    return &posixIoMethods;
+  if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
+    if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){
+      return &nfsIoMethods;
+    } else {
+      return &posixIoMethods;
+    }
   }else{
     return &dotlockIoMethods;
   }
 }
-static const sqlite3_io_methods *(*const autolockIoFinder)(const char*,int)
-        = autolockIoFinderImpl;
+static const sqlite3_io_methods 
+  *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;
 
 #endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
 
+#if OS_VXWORKS && SQLITE_ENABLE_LOCKING_STYLE
+/* 
+** This "finder" function attempts to determine the best locking strategy 
+** for the database file "filePath".  It then returns the sqlite3_io_methods
+** object that implements that strategy.
+**
+** This is for VXWorks only.
+*/
+static const sqlite3_io_methods *autolockIoFinderImpl(
+  const char *filePath,    /* name of the database file */
+  unixFile *pNew           /* the open file object */
+){
+  struct flock lockInfo;
+
+  if( !filePath ){
+    /* If filePath==NULL that means we are dealing with a transient file
+    ** that does not need to be locked. */
+    return &nolockIoMethods;
+  }
+
+  /* Test if fcntl() is supported and use POSIX style locks.
+  ** Otherwise fall back to the named semaphore method.
+  */
+  lockInfo.l_len = 1;
+  lockInfo.l_start = 0;
+  lockInfo.l_whence = SEEK_SET;
+  lockInfo.l_type = F_RDLCK;
+  if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
+    return &posixIoMethods;
+  }else{
+    return &semIoMethods;
+  }
+}
+static const sqlite3_io_methods 
+  *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;
+
+#endif /* OS_VXWORKS && SQLITE_ENABLE_LOCKING_STYLE */
+
 /*
 ** An abstract type for a pointer to a IO method finder function:
 */
-typedef const sqlite3_io_methods *(*finder_type)(const char*,int);
+typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*);
 
 
 /****************************************************************************
@@ -25085,44 +27371,55 @@ typedef const sqlite3_io_methods *(*finder_type)(const char*,int);
 static int fillInUnixFile(
   sqlite3_vfs *pVfs,      /* Pointer to vfs object */
   int h,                  /* Open file descriptor of file being opened */
-  int dirfd,              /* Directory file descriptor */
   sqlite3_file *pId,      /* Write to the unixFile structure here */
   const char *zFilename,  /* Name of the file being opened */
-  int noLock,             /* Omit locking if true */
-  int isDelete            /* Delete on close if true */
+  int ctrlFlags           /* Zero or more UNIXFILE_* values */
 ){
   const sqlite3_io_methods *pLockingStyle;
   unixFile *pNew = (unixFile *)pId;
   int rc = SQLITE_OK;
 
-  assert( pNew->pLock==NULL );
-  assert( pNew->pOpen==NULL );
+  assert( pNew->pInode==NULL );
 
-  /* Parameter isDelete is only used on vxworks.
-  ** Express this explicitly here to prevent compiler warnings
-  ** about unused parameters.
+  /* Usually the path zFilename should not be a relative pathname. The
+  ** exception is when opening the proxy "conch" file in builds that
+  ** include the special Apple locking styles.
   */
-#if !OS_VXWORKS
-  UNUSED_PARAMETER(isDelete);
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+  assert( zFilename==0 || zFilename[0]=='/' 
+    || pVfs->pAppData==(void*)&autolockIoFinder );
+#else
+  assert( zFilename==0 || zFilename[0]=='/' );
 #endif
 
-  OSTRACE3("OPEN    %-3d %s\n", h, zFilename);    
+  /* No locking occurs in temporary files */
+  assert( zFilename!=0 || (ctrlFlags & UNIXFILE_NOLOCK)!=0 );
+
+  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
   pNew->h = h;
-  pNew->dirfd = dirfd;
-  SET_THREADID(pNew);
+  pNew->pVfs = pVfs;
+  pNew->zPath = zFilename;
+  pNew->ctrlFlags = (u8)ctrlFlags;
+  if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0),
+                           "psow", SQLITE_POWERSAFE_OVERWRITE) ){
+    pNew->ctrlFlags |= UNIXFILE_PSOW;
+  }
+  if( memcmp(pVfs->zName,"unix-excl",10)==0 ){
+    pNew->ctrlFlags |= UNIXFILE_EXCL;
+  }
 
 #if OS_VXWORKS
   pNew->pId = vxworksFindFileId(zFilename);
   if( pNew->pId==0 ){
-    noLock = 1;
+    ctrlFlags |= UNIXFILE_NOLOCK;
     rc = SQLITE_NOMEM;
   }
 #endif
 
-  if( noLock ){
+  if( ctrlFlags & UNIXFILE_NOLOCK ){
     pLockingStyle = &nolockIoMethods;
   }else{
-    pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, h);
+    pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
 #if SQLITE_ENABLE_LOCKING_STYLE
     /* Cache zFilename in the locking context (AFP and dotlock override) for
     ** proxyLock activation is possible (remote proxy is based on db name)
@@ -25131,9 +27428,35 @@ static int fillInUnixFile(
 #endif
   }
 
-  if( pLockingStyle == &posixIoMethods ){
+  if( pLockingStyle == &posixIoMethods
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+    || pLockingStyle == &nfsIoMethods
+#endif
+  ){
     unixEnterMutex();
-    rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
+    rc = findInodeInfo(pNew, &pNew->pInode);
+    if( rc!=SQLITE_OK ){
+      /* If an error occured in findInodeInfo(), close the file descriptor
+      ** immediately, before releasing the mutex. findInodeInfo() may fail
+      ** in two scenarios:
+      **
+      **   (a) A call to fstat() failed.
+      **   (b) A malloc failed.
+      **
+      ** Scenario (b) may only occur if the process is holding no other
+      ** file descriptors open on the same file. If there were other file
+      ** descriptors on this file, then no malloc would be required by
+      ** findInodeInfo(). If this is the case, it is quite safe to close
+      ** handle h - as it is guaranteed that no posix locks will be released
+      ** by doing so.
+      **
+      ** If scenario (a) caused the error then things are not so safe. The
+      ** implicit assumption here is that if fstat() fails, things are in
+      ** such bad shape that dropping a lock or two doesn't matter much.
+      */
+      robust_close(pNew, h, __LINE__);
+      h = -1;
+    }
     unixLeaveMutex();
   }
 
@@ -25151,9 +27474,15 @@ static int fillInUnixFile(
       ** according to requirement F11141.  So we do not need to make a
       ** copy of the filename. */
       pCtx->dbPath = zFilename;
+      pCtx->reserved = 0;
       srandomdev();
       unixEnterMutex();
-      rc = findLockInfo(pNew, NULL, &pNew->pOpen);
+      rc = findInodeInfo(pNew, &pNew->pInode);
+      if( rc!=SQLITE_OK ){
+        sqlite3_free(pNew->lockingContext);
+        robust_close(pNew, h, __LINE__);
+        h = -1;
+      }
       unixLeaveMutex();        
     }
   }
@@ -25165,6 +27494,7 @@ static int fillInUnixFile(
     */
     char *zLockFile;
     int nFilename;
+    assert( zFilename!=0 );
     nFilename = (int)strlen(zFilename) + 6;
     zLockFile = (char *)sqlite3_malloc(nFilename);
     if( zLockFile==0 ){
@@ -25181,18 +27511,18 @@ static int fillInUnixFile(
     ** included in the semLockingContext
     */
     unixEnterMutex();
-    rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
-    if( (rc==SQLITE_OK) && (pNew->pOpen->pSem==NULL) ){
-      char *zSemName = pNew->pOpen->aSemName;
+    rc = findInodeInfo(pNew, &pNew->pInode);
+    if( (rc==SQLITE_OK) && (pNew->pInode->pSem==NULL) ){
+      char *zSemName = pNew->pInode->aSemName;
       int n;
-      sqlite3_snprintf(MAX_PATHNAME, zSemName, "%s.sem",
+      sqlite3_snprintf(MAX_PATHNAME, zSemName, "/%s.sem",
                        pNew->pId->zCanonicalName);
-      for( n=0; zSemName[n]; n++ )
+      for( n=1; zSemName[n]; n++ )
         if( zSemName[n]=='/' ) zSemName[n] = '_';
-      pNew->pOpen->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
-      if( pNew->pOpen->pSem == SEM_FAILED ){
+      pNew->pInode->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
+      if( pNew->pInode->pSem == SEM_FAILED ){
         rc = SQLITE_NOMEM;
-        pNew->pOpen->aSemName[0] = '\0';
+        pNew->pInode->aSemName[0] = '\0';
       }
     }
     unixLeaveMutex();
@@ -25202,14 +27532,15 @@ static int fillInUnixFile(
   pNew->lastErrno = 0;
 #if OS_VXWORKS
   if( rc!=SQLITE_OK ){
-    unlink(zFilename);
+    if( h>=0 ) robust_close(pNew, h, __LINE__);
+    h = -1;
+    osUnlink(zFilename);
     isDelete = 0;
   }
-  pNew->isDelete = isDelete;
+  if( isDelete ) pNew->ctrlFlags |= UNIXFILE_DELETE;
 #endif
   if( rc!=SQLITE_OK ){
-    if( dirfd>=0 ) close(dirfd); /* silent leak if fail, already in error */
-    close(h);
+    if( h>=0 ) robust_close(pNew, h, __LINE__);
   }else{
     pNew->pMethod = pLockingStyle;
     OpenCounter(+1);
@@ -25218,34 +27549,32 @@ static int fillInUnixFile(
 }
 
 /*
-** Open a file descriptor to the directory containing file zFilename.
-** If successful, *pFd is set to the opened file descriptor and
-** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM
-** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined
-** value.
-**
-** If SQLITE_OK is returned, the caller is responsible for closing
-** the file descriptor *pFd using close().
+** Return the name of a directory in which to put temporary files.
+** If no suitable temporary file directory can be found, return NULL.
 */
-static int openDirectory(const char *zFilename, int *pFd){
-  int ii;
-  int fd = -1;
-  char zDirname[MAX_PATHNAME+1];
+static const char *unixTempFileDir(void){
+  static const char *azDirs[] = {
+     0,
+     0,
+     "/var/tmp",
+     "/usr/tmp",
+     "/tmp",
+     0        /* List terminator */
+  };
+  unsigned int i;
+  struct stat buf;
+  const char *zDir = 0;
 
-  sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename);
-  for(ii=(int)strlen(zDirname); ii>1 && zDirname[ii]!='/'; ii--);
-  if( ii>0 ){
-    zDirname[ii] = '\0';
-    fd = open(zDirname, O_RDONLY|O_BINARY, 0);
-    if( fd>=0 ){
-#ifdef FD_CLOEXEC
-      fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
-#endif
-      OSTRACE3("OPENDIR %-3d %s\n", fd, zDirname);
-    }
+  azDirs[0] = sqlite3_temp_directory;
+  if( !azDirs[1] ) azDirs[1] = getenv("TMPDIR");
+  for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){
+    if( zDir==0 ) continue;
+    if( osStat(zDir, &buf) ) continue;
+    if( !S_ISDIR(buf.st_mode) ) continue;
+    if( osAccess(zDir, 07) ) continue;
+    break;
   }
-  *pFd = fd;
-  return (fd>=0?SQLITE_OK:SQLITE_CANTOPEN);
+  return zDir;
 }
 
 /*
@@ -25253,22 +27582,13 @@ static int openDirectory(const char *zFilename, int *pFd){
 ** by the calling process and must be big enough to hold at least
 ** pVfs->mxPathname bytes.
 */
-static int getTempname(int nBuf, char *zBuf){
-  static const char *azDirs[] = {
-     0,
-     0,
-     "/var/tmp",
-     "/usr/tmp",
-     "/tmp",
-     ".",
-  };
+static int unixGetTempname(int nBuf, char *zBuf){
   static const unsigned char zChars[] =
     "abcdefghijklmnopqrstuvwxyz"
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "0123456789";
   unsigned int i, j;
-  struct stat buf;
-  const char *zDir = ".";
+  const char *zDir;
 
   /* It's odd to simulate an io-error here, but really this is just
   ** using the io-error infrastructure to test that SQLite handles this
@@ -25276,36 +27596,26 @@ static int getTempname(int nBuf, char *zBuf){
   */
   SimulateIOError( return SQLITE_IOERR );
 
-  azDirs[0] = sqlite3_temp_directory;
-  if (NULL == azDirs[1]) {
-    azDirs[1] = getenv("TMPDIR");
-  }
-  
-  for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); i++){
-    if( azDirs[i]==0 ) continue;
-    if( stat(azDirs[i], &buf) ) continue;
-    if( !S_ISDIR(buf.st_mode) ) continue;
-    if( access(azDirs[i], 07) ) continue;
-    zDir = azDirs[i];
-    break;
-  }
+  zDir = unixTempFileDir();
+  if( zDir==0 ) zDir = ".";
 
   /* Check that the output buffer is large enough for the temporary file 
   ** name. If it is not, return SQLITE_ERROR.
   */
-  if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 17) >= (size_t)nBuf ){
+  if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 18) >= (size_t)nBuf ){
     return SQLITE_ERROR;
   }
 
   do{
-    sqlite3_snprintf(nBuf-17, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
+    sqlite3_snprintf(nBuf-18, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
     j = (int)strlen(zBuf);
     sqlite3_randomness(15, &zBuf[j]);
     for(i=0; i<15; i++, j++){
       zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
     }
     zBuf[j] = 0;
-  }while( access(zBuf,0)==0 );
+    zBuf[j+1] = 0;
+  }while( osAccess(zBuf,0)==0 );
   return SQLITE_OK;
 }
 
@@ -25318,6 +27628,139 @@ static int getTempname(int nBuf, char *zBuf){
 static int proxyTransformUnixFile(unixFile*, const char*);
 #endif
 
+/*
+** Search for an unused file descriptor that was opened on the database 
+** file (not a journal or master-journal file) identified by pathname
+** zPath with SQLITE_OPEN_XXX flags matching those passed as the second
+** argument to this function.
+**
+** Such a file descriptor may exist if a database connection was closed
+** but the associated file descriptor could not be closed because some
+** other file descriptor open on the same file is holding a file-lock.
+** Refer to comments in the unixClose() function and the lengthy comment
+** describing "Posix Advisory Locking" at the start of this file for 
+** further details. Also, ticket #4018.
+**
+** If a suitable file descriptor is found, then it is returned. If no
+** such file descriptor is located, -1 is returned.
+*/
+static UnixUnusedFd *findReusableFd(const char *zPath, int flags){
+  UnixUnusedFd *pUnused = 0;
+
+  /* Do not search for an unused file descriptor on vxworks. Not because
+  ** vxworks would not benefit from the change (it might, we're not sure),
+  ** but because no way to test it is currently available. It is better 
+  ** not to risk breaking vxworks support for the sake of such an obscure 
+  ** feature.  */
+#if !OS_VXWORKS
+  struct stat sStat;                   /* Results of stat() call */
+
+  /* A stat() call may fail for various reasons. If this happens, it is
+  ** almost certain that an open() call on the same path will also fail.
+  ** For this reason, if an error occurs in the stat() call here, it is
+  ** ignored and -1 is returned. The caller will try to open a new file
+  ** descriptor on the same path, fail, and return an error to SQLite.
+  **
+  ** Even if a subsequent open() call does succeed, the consequences of
+  ** not searching for a resusable file descriptor are not dire.  */
+  if( 0==osStat(zPath, &sStat) ){
+    unixInodeInfo *pInode;
+
+    unixEnterMutex();
+    pInode = inodeList;
+    while( pInode && (pInode->fileId.dev!=sStat.st_dev
+                     || pInode->fileId.ino!=sStat.st_ino) ){
+       pInode = pInode->pNext;
+    }
+    if( pInode ){
+      UnixUnusedFd **pp;
+      for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
+      pUnused = *pp;
+      if( pUnused ){
+        *pp = pUnused->pNext;
+      }
+    }
+    unixLeaveMutex();
+  }
+#endif    /* if !OS_VXWORKS */
+  return pUnused;
+}
+
+/*
+** This function is called by unixOpen() to determine the unix permissions
+** to create new files with. If no error occurs, then SQLITE_OK is returned
+** and a value suitable for passing as the third argument to open(2) is
+** written to *pMode. If an IO error occurs, an SQLite error code is 
+** returned and the value of *pMode is not modified.
+**
+** In most cases cases, this routine sets *pMode to 0, which will become
+** an indication to robust_open() to create the file using
+** SQLITE_DEFAULT_FILE_PERMISSIONS adjusted by the umask.
+** But if the file being opened is a WAL or regular journal file, then 
+** this function queries the file-system for the permissions on the 
+** corresponding database file and sets *pMode to this value. Whenever 
+** possible, WAL and journal files are created using the same permissions 
+** as the associated database file.
+**
+** If the SQLITE_ENABLE_8_3_NAMES option is enabled, then the
+** original filename is unavailable.  But 8_3_NAMES is only used for
+** FAT filesystems and permissions do not matter there, so just use
+** the default permissions.
+*/
+static int findCreateFileMode(
+  const char *zPath,              /* Path of file (possibly) being created */
+  int flags,                      /* Flags passed as 4th argument to xOpen() */
+  mode_t *pMode,                  /* OUT: Permissions to open file with */
+  uid_t *pUid,                    /* OUT: uid to set on the file */
+  gid_t *pGid                     /* OUT: gid to set on the file */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  *pMode = 0;
+  *pUid = 0;
+  *pGid = 0;
+  if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){
+    char zDb[MAX_PATHNAME+1];     /* Database file path */
+    int nDb;                      /* Number of valid bytes in zDb */
+    struct stat sStat;            /* Output of stat() on database file */
+
+    /* zPath is a path to a WAL or journal file. The following block derives
+    ** the path to the associated database file from zPath. This block handles
+    ** the following naming conventions:
+    **
+    **   "<path to db>-journal"
+    **   "<path to db>-wal"
+    **   "<path to db>-journalNN"
+    **   "<path to db>-walNN"
+    **
+    ** where NN is a decimal number. The NN naming schemes are 
+    ** used by the test_multiplex.c module.
+    */
+    nDb = sqlite3Strlen30(zPath) - 1; 
+#ifdef SQLITE_ENABLE_8_3_NAMES
+    while( nDb>0 && sqlite3Isalnum(zPath[nDb]) ) nDb--;
+    if( nDb==0 || zPath[nDb]!='-' ) return SQLITE_OK;
+#else
+    while( zPath[nDb]!='-' ){
+      assert( nDb>0 );
+      assert( zPath[nDb]!='\n' );
+      nDb--;
+    }
+#endif
+    memcpy(zDb, zPath, nDb);
+    zDb[nDb] = '\0';
+
+    if( 0==osStat(zDb, &sStat) ){
+      *pMode = sStat.st_mode & 0777;
+      *pUid = sStat.st_uid;
+      *pGid = sStat.st_gid;
+    }else{
+      rc = SQLITE_IOERR_FSTAT;
+    }
+  }else if( flags & SQLITE_OPEN_DELETEONCLOSE ){
+    *pMode = 0600;
+  }
+  return rc;
+}
 
 /*
 ** Open the file zPath.
@@ -25348,31 +27791,40 @@ static int unixOpen(
   int flags,                   /* Input flags to control the opening */
   int *pOutFlags               /* Output flags returned to SQLite core */
 ){
-  int fd = 0;                    /* File descriptor returned by open() */
-  int dirfd = -1;                /* Directory file descriptor */
+  unixFile *p = (unixFile *)pFile;
+  int fd = -1;                   /* File descriptor returned by open() */
   int openFlags = 0;             /* Flags to pass to open() */
   int eType = flags&0xFFFFFF00;  /* Type of file to open */
   int noLock;                    /* True to omit locking primitives */
-  int rc = SQLITE_OK;
+  int rc = SQLITE_OK;            /* Function Return Code */
+  int ctrlFlags = 0;             /* UNIXFILE_* flags */
 
   int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
   int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
   int isCreate     = (flags & SQLITE_OPEN_CREATE);
   int isReadonly   = (flags & SQLITE_OPEN_READONLY);
   int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
+#if SQLITE_ENABLE_LOCKING_STYLE
+  int isAutoProxy  = (flags & SQLITE_OPEN_AUTOPROXY);
+#endif
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+  struct statfs fsInfo;
+#endif
 
   /* If creating a master or main-file journal, this function will open
   ** a file-descriptor on the directory too. The first time unixSync()
   ** is called the directory file descriptor will be fsync()ed and close()d.
   */
-  int isOpenDirectory = (isCreate && 
-      (eType==SQLITE_OPEN_MASTER_JOURNAL || eType==SQLITE_OPEN_MAIN_JOURNAL)
-  );
+  int syncDir = (isCreate && (
+        eType==SQLITE_OPEN_MASTER_JOURNAL 
+     || eType==SQLITE_OPEN_MAIN_JOURNAL 
+     || eType==SQLITE_OPEN_WAL
+  ));
 
   /* If argument zPath is a NULL pointer, this function is required to open
   ** a temporary file. Use this buffer to store the file name in.
   */
-  char zTmpname[MAX_PATHNAME+1];
+  char zTmpname[MAX_PATHNAME+2];
   const char *zName = zPath;
 
   /* Check the following statements are true: 
@@ -25387,113 +27839,198 @@ static int unixOpen(
   assert(isExclusive==0 || isCreate);
   assert(isDelete==0 || isCreate);
 
-  /* The main DB, main journal, and master journal are never automatically
-  ** deleted
-  */
-  assert( eType!=SQLITE_OPEN_MAIN_DB || !isDelete );
-  assert( eType!=SQLITE_OPEN_MAIN_JOURNAL || !isDelete );
-  assert( eType!=SQLITE_OPEN_MASTER_JOURNAL || !isDelete );
+  /* The main DB, main journal, WAL file and master journal are never 
+  ** automatically deleted. Nor are they ever temporary files.  */
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MASTER_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL );
 
   /* Assert that the upper layer has set one of the "file-type" flags. */
   assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB 
        || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL 
        || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_MASTER_JOURNAL 
-       || eType==SQLITE_OPEN_TRANSIENT_DB
+       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
   );
 
-  memset(pFile, 0, sizeof(unixFile));
+  memset(p, 0, sizeof(unixFile));
 
-  if( !zName ){
-    assert(isDelete && !isOpenDirectory);
-    rc = getTempname(MAX_PATHNAME+1, zTmpname);
+  if( eType==SQLITE_OPEN_MAIN_DB ){
+    UnixUnusedFd *pUnused;
+    pUnused = findReusableFd(zName, flags);
+    if( pUnused ){
+      fd = pUnused->fd;
+    }else{
+      pUnused = sqlite3_malloc(sizeof(*pUnused));
+      if( !pUnused ){
+        return SQLITE_NOMEM;
+      }
+    }
+    p->pUnused = pUnused;
+
+    /* Database filenames are double-zero terminated if they are not
+    ** URIs with parameters.  Hence, they can always be passed into
+    ** sqlite3_uri_parameter(). */
+    assert( (flags & SQLITE_OPEN_URI) || zName[strlen(zName)+1]==0 );
+
+  }else if( !zName ){
+    /* If zName is NULL, the upper layer is requesting a temp file. */
+    assert(isDelete && !syncDir);
+    rc = unixGetTempname(MAX_PATHNAME+2, zTmpname);
     if( rc!=SQLITE_OK ){
       return rc;
     }
     zName = zTmpname;
+
+    /* Generated temporary filenames are always double-zero terminated
+    ** for use by sqlite3_uri_parameter(). */
+    assert( zName[strlen(zName)+1]==0 );
   }
 
+  /* Determine the value of the flags parameter passed to POSIX function
+  ** open(). These must be calculated even if open() is not called, as
+  ** they may be stored as part of the file handle and used by the 
+  ** 'conch file' locking functions later on.  */
   if( isReadonly )  openFlags |= O_RDONLY;
   if( isReadWrite ) openFlags |= O_RDWR;
   if( isCreate )    openFlags |= O_CREAT;
   if( isExclusive ) openFlags |= (O_EXCL|O_NOFOLLOW);
   openFlags |= (O_LARGEFILE|O_BINARY);
 
-  fd = open(zName, openFlags, isDelete?0600:SQLITE_DEFAULT_FILE_PERMISSIONS);
-  OSTRACE4("OPENX   %-3d %s 0%o\n", fd, zName, openFlags);
-  if( fd<0 && errno!=EISDIR && isReadWrite && !isExclusive ){
-    /* Failed to open the file for read/write access. Try read-only. */
-    flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
-    flags |= SQLITE_OPEN_READONLY;
-    return unixOpen(pVfs, zPath, pFile, flags, pOutFlags);
-  }
   if( fd<0 ){
-    return SQLITE_CANTOPEN;
+    mode_t openMode;              /* Permissions to create file with */
+    uid_t uid;                    /* Userid for the file */
+    gid_t gid;                    /* Groupid for the file */
+    rc = findCreateFileMode(zName, flags, &openMode, &uid, &gid);
+    if( rc!=SQLITE_OK ){
+      assert( !p->pUnused );
+      assert( eType==SQLITE_OPEN_WAL || eType==SQLITE_OPEN_MAIN_JOURNAL );
+      return rc;
+    }
+    fd = robust_open(zName, openFlags, openMode);
+    OSTRACE(("OPENX   %-3d %s 0%o\n", fd, zName, openFlags));
+    if( fd<0 && errno!=EISDIR && isReadWrite && !isExclusive ){
+      /* Failed to open the file for read/write access. Try read-only. */
+      flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
+      openFlags &= ~(O_RDWR|O_CREAT);
+      flags |= SQLITE_OPEN_READONLY;
+      openFlags |= O_RDONLY;
+      isReadonly = 1;
+      fd = robust_open(zName, openFlags, openMode);
+    }
+    if( fd<0 ){
+      rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zName);
+      goto open_finished;
+    }
+
+    /* If this process is running as root and if creating a new rollback
+    ** journal or WAL file, set the ownership of the journal or WAL to be
+    ** the same as the original database.
+    */
+    if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){
+      osFchown(fd, uid, gid);
+    }
   }
-  if( isDelete ){
-#if OS_VXWORKS
-    zPath = zName;
-#else
-    unlink(zName);
-#endif
-  }
-#if SQLITE_ENABLE_LOCKING_STYLE
-  else{
-    ((unixFile*)pFile)->openFlags = openFlags;
-  }
-#endif
+  assert( fd>=0 );
   if( pOutFlags ){
     *pOutFlags = flags;
   }
 
-  assert(fd!=0);
-  if( isOpenDirectory ){
-    rc = openDirectory(zPath, &dirfd);
-    if( rc!=SQLITE_OK ){
-      close(fd); /* silently leak if fail, already in error */
-      return rc;
-    }
+  if( p->pUnused ){
+    p->pUnused->fd = fd;
+    p->pUnused->flags = flags;
   }
 
-#ifdef FD_CLOEXEC
-  fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
+  if( isDelete ){
+#if OS_VXWORKS
+    zPath = zName;
+#else
+    osUnlink(zName);
+#endif
+  }
+#if SQLITE_ENABLE_LOCKING_STYLE
+  else{
+    p->openFlags = openFlags;
+  }
 #endif
 
   noLock = eType!=SQLITE_OPEN_MAIN_DB;
 
+  
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+  if( fstatfs(fd, &fsInfo) == -1 ){
+    ((unixFile*)pFile)->lastErrno = errno;
+    robust_close(p, fd, __LINE__);
+    return SQLITE_IOERR_ACCESS;
+  }
+  if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) {
+    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
+  }
+#endif
+
+  /* Set up appropriate ctrlFlags */
+  if( isDelete )                ctrlFlags |= UNIXFILE_DELETE;
+  if( isReadonly )              ctrlFlags |= UNIXFILE_RDONLY;
+  if( noLock )                  ctrlFlags |= UNIXFILE_NOLOCK;
+  if( syncDir )                 ctrlFlags |= UNIXFILE_DIRSYNC;
+  if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI;
+
+#if SQLITE_ENABLE_LOCKING_STYLE
 #if SQLITE_PREFER_PROXY_LOCKING
-  if( zPath!=NULL && !noLock ){
+  isAutoProxy = 1;
+#endif
+  if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
     char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
     int useProxy = 0;
 
-    /* SQLITE_FORCE_PROXY_LOCKING==1 means force always use proxy, 
-    ** 0 means never use proxy, NULL means use proxy for non-local files only
-    */
+    /* SQLITE_FORCE_PROXY_LOCKING==1 means force always use proxy, 0 means 
+    ** never use proxy, NULL means use proxy for non-local files only.  */
     if( envforce!=NULL ){
       useProxy = atoi(envforce)>0;
     }else{
-      struct statfs fsInfo;
-
       if( statfs(zPath, &fsInfo) == -1 ){
-				((unixFile*)pFile)->lastErrno = errno;
-        if( dirfd>=0 ) close(dirfd); /* silently leak if fail, in error */
-        close(fd); /* silently leak if fail, in error */
-        return SQLITE_IOERR_ACCESS;
+        /* In theory, the close(fd) call is sub-optimal. If the file opened
+        ** with fd is a database file, and there are other connections open
+        ** on that file that are currently holding advisory locks on it,
+        ** then the call to close() will cancel those locks. In practice,
+        ** we're assuming that statfs() doesn't fail very often. At least
+        ** not while other file descriptors opened by the same process on
+        ** the same file are working.  */
+        p->lastErrno = errno;
+        robust_close(p, fd, __LINE__);
+        rc = SQLITE_IOERR_ACCESS;
+        goto open_finished;
       }
       useProxy = !(fsInfo.f_flags&MNT_LOCAL);
     }
     if( useProxy ){
-      rc = fillInUnixFile(pVfs, fd, dirfd, pFile, zPath, noLock, isDelete);
+      rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
       if( rc==SQLITE_OK ){
         rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
+        if( rc!=SQLITE_OK ){
+          /* Use unixClose to clean up the resources added in fillInUnixFile 
+          ** and clear all the structure's references.  Specifically, 
+          ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op 
+          */
+          unixClose(pFile);
+          return rc;
+        }
       }
-      return rc;
+      goto open_finished;
     }
   }
 #endif
   
-  return fillInUnixFile(pVfs, fd, dirfd, pFile, zPath, noLock, isDelete);
+  rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
+
+open_finished:
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(p->pUnused);
+  }
+  return rc;
 }
 
+
 /*
 ** Delete the file at zPath. If the dirSync argument is true, fsync()
 ** the directory after deleting the file.
@@ -25506,11 +28043,13 @@ static int unixDelete(
   int rc = SQLITE_OK;
   UNUSED_PARAMETER(NotUsed);
   SimulateIOError(return SQLITE_IOERR_DELETE);
-  unlink(zPath);
+  if( osUnlink(zPath)==(-1) && errno!=ENOENT ){
+    return unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
+  }
 #ifndef SQLITE_DISABLE_DIRSYNC
-  if( dirSync ){
+  if( (dirSync & 1)!=0 ){
     int fd;
-    rc = openDirectory(zPath, &fd);
+    rc = osOpenDirectory(zPath, &fd);
     if( rc==SQLITE_OK ){
 #if OS_VXWORKS
       if( fsync(fd)==-1 )
@@ -25518,11 +28057,11 @@ static int unixDelete(
       if( fsync(fd) )
 #endif
       {
-        rc = SQLITE_IOERR_DIR_FSYNC;
-      }
-      if( close(fd)&&!rc ){
-        rc = SQLITE_IOERR_DIR_CLOSE;
+        rc = unixLogError(SQLITE_IOERR_DIR_FSYNC, "fsync", zPath);
       }
+      robust_close(0, fd, __LINE__);
+    }else if( rc==SQLITE_CANTOPEN ){
+      rc = SQLITE_OK;
     }
   }
 #endif
@@ -25562,7 +28101,13 @@ static int unixAccess(
     default:
       assert(!"Invalid flags argument");
   }
-  *pResOut = (access(zPath, amode)==0);
+  *pResOut = (osAccess(zPath, amode)==0);
+  if( flags==SQLITE_ACCESS_EXISTS && *pResOut ){
+    struct stat buf;
+    if( 0==osStat(zPath, &buf) && buf.st_size==0 ){
+      *pResOut = 0;
+    }
+  }
   return SQLITE_OK;
 }
 
@@ -25598,8 +28143,8 @@ static int unixFullPathname(
     sqlite3_snprintf(nOut, zOut, "%s", zPath);
   }else{
     int nCwd;
-    if( getcwd(zOut, nOut-1)==0 ){
-      return SQLITE_CANTOPEN;
+    if( osGetcwd(zOut, nOut-1)==0 ){
+      return unixLogError(SQLITE_CANTOPEN_BKPT, "getcwd", zPath);
     }
     nCwd = (int)strlen(zOut);
     sqlite3_snprintf(nOut-nCwd, &zOut[nCwd], "/%s", zPath);
@@ -25627,7 +28172,7 @@ static void *unixDlOpen(sqlite3_vfs *NotUsed, const char *zFilename){
 ** error message.
 */
 static void unixDlError(sqlite3_vfs *NotUsed, int nBuf, char *zBufOut){
-  char *zErr;
+  const char *zErr;
   UNUSED_PARAMETER(NotUsed);
   unixEnterMutex();
   zErr = dlerror();
@@ -25692,8 +28237,8 @@ static int unixRandomness(sqlite3_vfs *NotUsed, int nBuf, char *zBuf){
   memset(zBuf, 0, nBuf);
 #if !defined(SQLITE_TEST)
   {
-    int pid, fd;
-    fd = open("/dev/urandom", O_RDONLY);
+    int pid, fd, got;
+    fd = robust_open("/dev/urandom", O_RDONLY, 0);
     if( fd<0 ){
       time_t t;
       time(&t);
@@ -25703,8 +28248,8 @@ static int unixRandomness(sqlite3_vfs *NotUsed, int nBuf, char *zBuf){
       assert( sizeof(t)+sizeof(pid)<=(size_t)nBuf );
       nBuf = sizeof(t) + sizeof(pid);
     }else{
-      nBuf = read(fd, zBuf, nBuf);
-      close(fd);
+      do{ got = osRead(fd, zBuf, nBuf); }while( got<0 && errno==EINTR );
+      robust_close(0, fd, __LINE__);
     }
   }
 #endif
@@ -25727,16 +28272,18 @@ static int unixSleep(sqlite3_vfs *NotUsed, int microseconds){
   sp.tv_sec = microseconds / 1000000;
   sp.tv_nsec = (microseconds % 1000000) * 1000;
   nanosleep(&sp, NULL);
+  UNUSED_PARAMETER(NotUsed);
   return microseconds;
 #elif defined(HAVE_USLEEP) && HAVE_USLEEP
   usleep(microseconds);
+  UNUSED_PARAMETER(NotUsed);
   return microseconds;
 #else
   int seconds = (microseconds+999999)/1000000;
   sleep(seconds);
+  UNUSED_PARAMETER(NotUsed);
   return seconds*1000000;
 #endif
-  UNUSED_PARAMETER(NotUsed);
 }
 
 /*
@@ -25748,33 +28295,57 @@ static int unixSleep(sqlite3_vfs *NotUsed, int microseconds){
 SQLITE_API int sqlite3_current_time = 0;  /* Fake system time in seconds since 1970. */
 #endif
 
+/*
+** Find the current time (in Universal Coordinated Time).  Write into *piNow
+** the current time and date as a Julian Day number times 86_400_000.  In
+** other words, write into *piNow the number of milliseconds since the Julian
+** epoch of noon in Greenwich on November 24, 4714 B.C according to the
+** proleptic Gregorian calendar.
+**
+** On success, return SQLITE_OK.  Return SQLITE_ERROR if the time and date 
+** cannot be found.
+*/
+static int unixCurrentTimeInt64(sqlite3_vfs *NotUsed, sqlite3_int64 *piNow){
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+  int rc = SQLITE_OK;
+#if defined(NO_GETTOD)
+  time_t t;
+  time(&t);
+  *piNow = ((sqlite3_int64)t)*1000 + unixEpoch;
+#elif OS_VXWORKS
+  struct timespec sNow;
+  clock_gettime(CLOCK_REALTIME, &sNow);
+  *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_nsec/1000000;
+#else
+  struct timeval sNow;
+  if( gettimeofday(&sNow, 0)==0 ){
+    *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000;
+  }else{
+    rc = SQLITE_ERROR;
+  }
+#endif
+
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
+  }
+#endif
+  UNUSED_PARAMETER(NotUsed);
+  return rc;
+}
+
 /*
 ** Find the current time (in Universal Coordinated Time).  Write the
 ** current time and date as a Julian Day number into *prNow and
 ** return 0.  Return 1 if the time and date cannot be found.
 */
 static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){
-#if defined(NO_GETTOD)
-  time_t t;
-  time(&t);
-  *prNow = t/86400.0 + 2440587.5;
-#elif OS_VXWORKS
-  struct timespec sNow;
-  clock_gettime(CLOCK_REALTIME, &sNow);
-  *prNow = 2440587.5 + sNow.tv_sec/86400.0 + sNow.tv_nsec/86400000000000.0;
-#else
-  struct timeval sNow;
-  gettimeofday(&sNow, 0);
-  *prNow = 2440587.5 + sNow.tv_sec/86400.0 + sNow.tv_usec/86400000000.0;
-#endif
-
-#ifdef SQLITE_TEST
-  if( sqlite3_current_time ){
-    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
-  }
-#endif
+  sqlite3_int64 i = 0;
+  int rc;
   UNUSED_PARAMETER(NotUsed);
-  return 0;
+  rc = unixCurrentTimeInt64(0, &i);
+  *prNow = i/86400000.0;
+  return rc;
 }
 
 /*
@@ -25791,6 +28362,7 @@ static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
   return 0;
 }
 
+
 /*
 ************************ End of sqlite3_vfs methods ***************************
 ******************************************************************************/
@@ -25819,7 +28391,7 @@ static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
 ** address in the shared range is taken for a SHARED lock, the entire
 ** shared range is taken for an EXCLUSIVE lock):
 **
-**      PENDING_BYTE        0x40000000		   	
+**      PENDING_BYTE        0x40000000
 **      RESERVED_BYTE       0x40000001
 **      SHARED_RANGE        0x40000002 -> 0x40000200
 **
@@ -25900,11 +28472,6 @@ static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
 ** of the database file for multiple readers and writers on the same
 ** host (the conch ensures that they all use the same local lock file).
 **
-** There is a third file - the host ID file - used as a persistent record
-** of a unique identifier for the host, a 128-byte unique host id file
-** in the path defined by the HOSTIDPATH macro (default value is
-** /Library/Caches/.com.apple.sqliteConchHostId).
-**
 ** Requesting the lock proxy does not immediately take the conch, it is
 ** only taken when the first request to lock database file is made.  
 ** This matches the semantics of the traditional locking behavior, where
@@ -25930,10 +28497,6 @@ static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
 **       Enables the logging of error messages during host id file
 **       retrieval and creation
 **
-**  HOSTIDPATH
-**
-**       Overrides the default host ID file path location
-**
 **  LOCKPROXYDIR
 **
 **       Overrides the default directory used for lock proxy files that
@@ -25958,11 +28521,6 @@ static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
 */
 #if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
 
-#ifdef SQLITE_TEST
-/* simulate multiple hosts by creating unique hostid file paths */
-SQLITE_API int sqlite3_hostid_num = 0;
-#endif
-
 /*
 ** The proxyLockingContext has the path and file structures for the remote 
 ** and local proxy files in it
@@ -25974,134 +28532,16 @@ struct proxyLockingContext {
   unixFile *lockProxy;         /* Open proxy lock file */
   char *lockProxyPath;         /* Name of the proxy lock file */
   char *dbPath;                /* Name of the open file */
-  int conchHeld;               /* True if the conch is currently held */
+  int conchHeld;               /* 1 if the conch is held, -1 if lockless */
   void *oldLockingContext;     /* Original lockingcontext to restore on close */
   sqlite3_io_methods const *pOldMethod;     /* Original I/O methods for close */
 };
 
-/* HOSTIDLEN and CONCHLEN both include space for the string 
-** terminating nul 
+/* 
+** The proxy lock file path for the database at dbPath is written into lPath, 
+** which must point to valid, writable memory large enough for a maxLen length
+** file path. 
 */
-#define HOSTIDLEN         128
-#define CONCHLEN          (MAXPATHLEN+HOSTIDLEN+1)
-#ifndef HOSTIDPATH
-# define HOSTIDPATH       "/Library/Caches/.com.apple.sqliteConchHostId"
-#endif
-
-/* basically a copy of unixRandomness with different
-** test behavior built in */
-static int proxyGenerateHostID(char *pHostID){
-  int pid, fd, len;
-  unsigned char *key = (unsigned char *)pHostID;
-  
-  memset(key, 0, HOSTIDLEN);
-  len = 0;
-  fd = open("/dev/urandom", O_RDONLY);
-  if( fd>=0 ){
-    len = read(fd, key, HOSTIDLEN);
-    close(fd); /* silently leak the fd if it fails */
-  }
-  if( len < HOSTIDLEN ){
-    time_t t;
-    time(&t);
-    memcpy(key, &t, sizeof(t));
-    pid = getpid();
-    memcpy(&key[sizeof(t)], &pid, sizeof(pid));
-  }
-  
-#ifdef MAKE_PRETTY_HOSTID
-  {
-    int i;
-    /* filter the bytes into printable ascii characters and NUL terminate */
-    key[(HOSTIDLEN-1)] = 0x00;
-    for( i=0; i<(HOSTIDLEN-1); i++ ){
-      unsigned char pa = key[i]&0x7F;
-      if( pa<0x20 ){
-        key[i] = (key[i]&0x80 == 0x80) ? pa+0x40 : pa+0x20;
-      }else if( pa==0x7F ){
-        key[i] = (key[i]&0x80 == 0x80) ? pa=0x20 : pa+0x7E;
-      }
-    }
-  }
-#endif
-  return SQLITE_OK;
-}
-
-/* writes the host id path to path, path should be an pre-allocated buffer
-** with enough space for a path 
-*/
-static void proxyGetHostIDPath(char *path, size_t len){
-  strlcpy(path, HOSTIDPATH, len);
-#ifdef SQLITE_TEST
-  if( sqlite3_hostid_num>0 ){
-    char suffix[2] = "1";
-    suffix[0] = suffix[0] + sqlite3_hostid_num;
-    strlcat(path, suffix, len);
-  }
-#endif
-  OSTRACE3("GETHOSTIDPATH  %s pid=%d\n", path, getpid());
-}
-
-/* get the host ID from a sqlite hostid file stored in the 
-** user-specific tmp directory, create the ID if it's not there already 
-*/
-static int proxyGetHostID(char *pHostID, int *pError){
-  int fd;
-  char path[MAXPATHLEN]; 
-  size_t len;
-  int rc=SQLITE_OK;
-
-  proxyGetHostIDPath(path, MAXPATHLEN);
-  /* try to create the host ID file, if it already exists read the contents */
-  fd = open(path, O_CREAT|O_WRONLY|O_EXCL, 0644);
-  if( fd<0 ){
-    int err=errno;
-		
-    if( err!=EEXIST ){
-#ifdef SQLITE_PROXY_DEBUG /* set the sqlite error message instead */
-      fprintf(stderr, "sqlite error creating host ID file %s: %s\n",
-              path, strerror(err));
-#endif
-      return SQLITE_PERM;
-    }
-    /* couldn't create the file, read it instead */
-    fd = open(path, O_RDONLY|O_EXCL);
-    if( fd<0 ){
-#ifdef SQLITE_PROXY_DEBUG /* set the sqlite error message instead */
-      int err = errno;
-      fprintf(stderr, "sqlite error opening host ID file %s: %s\n",
-              path, strerror(err));
-#endif
-      return SQLITE_PERM;
-    }
-    len = pread(fd, pHostID, HOSTIDLEN, 0);
-    if( len<0 ){
-      *pError = errno;
-      rc = SQLITE_IOERR_READ;
-    }else if( len<HOSTIDLEN ){
-      *pError = 0;
-      rc = SQLITE_IOERR_SHORT_READ;
-    }
-    close(fd); /* silently leak the fd if it fails */
-    OSTRACE3("GETHOSTID  read %s pid=%d\n", pHostID, getpid());
-    return rc;
-  }else{
-    /* we're creating the host ID file (use a random string of bytes) */
-    proxyGenerateHostID(pHostID);
-    len = pwrite(fd, pHostID, HOSTIDLEN, 0);
-    if( len<0 ){
-      *pError = errno;
-      rc = SQLITE_IOERR_WRITE;
-    }else if( len<HOSTIDLEN ){
-      *pError = 0;
-      rc = SQLITE_IOERR_WRITE;
-    }
-    close(fd); /* silently leak the fd if it fails */
-    OSTRACE3("GETHOSTID  wrote %s pid=%d\n", pHostID, getpid());
-    return rc;
-  }
-}
-
 static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
   int len;
   int dbLen;
@@ -26112,21 +28552,12 @@ static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
 #else
 # ifdef _CS_DARWIN_USER_TEMP_DIR
   {
-    confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen);
-    len = strlcat(lPath, "sqliteplocks", maxLen);
-    if( mkdir(lPath, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
-      /* if mkdir fails, handle as lock file creation failure */
-      int err = errno;
-#  ifdef SQLITE_DEBUG
-      if( err!=EEXIST ){
-        fprintf(stderr, "proxyGetLockPath: mkdir(%s,0%o) error %d %s\n", lPath,
-                SQLITE_DEFAULT_PROXYDIR_PERMISSIONS, err, strerror(err));
-      }
-#  endif
-    }else{
-      OSTRACE3("GETLOCKPATH  mkdir %s pid=%d\n", lPath, getpid());
+    if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){
+      OSTRACE(("GETLOCKPATH  failed %s errno=%d pid=%d\n",
+               lPath, errno, getpid()));
+      return SQLITE_IOERR_LOCK;
     }
-    
+    len = strlcat(lPath, "sqliteplocks", maxLen);    
   }
 # else
   len = strlcpy(lPath, "/tmp/", maxLen);
@@ -26139,15 +28570,52 @@ static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
   
   /* transform the db path to a unique cache name */
   dbLen = (int)strlen(dbPath);
-  for( i=0; i<dbLen && (i+len+7)<maxLen; i++){
+  for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){
     char c = dbPath[i];
     lPath[i+len] = (c=='/')?'_':c;
   }
   lPath[i+len]='\0';
   strlcat(lPath, ":auto:", maxLen);
+  OSTRACE(("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, getpid()));
   return SQLITE_OK;
 }
 
+/* 
+ ** Creates the lock file and any missing directories in lockPath
+ */
+static int proxyCreateLockPath(const char *lockPath){
+  int i, len;
+  char buf[MAXPATHLEN];
+  int start = 0;
+  
+  assert(lockPath!=NULL);
+  /* try to create all the intermediate directories */
+  len = (int)strlen(lockPath);
+  buf[0] = lockPath[0];
+  for( i=1; i<len; i++ ){
+    if( lockPath[i] == '/' && (i - start > 0) ){
+      /* only mkdir if leaf dir != "." or "/" or ".." */
+      if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/') 
+         || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
+        buf[i]='\0';
+        if( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
+          int err=errno;
+          if( err!=EEXIST ) {
+            OSTRACE(("CREATELOCKPATH  FAILED creating %s, "
+                     "'%s' proxy lock path=%s pid=%d\n",
+                     buf, strerror(err), lockPath, getpid()));
+            return err;
+          }
+        }
+      }
+      start=i+1;
+    }
+    buf[i] = lockPath[i];
+  }
+  OSTRACE(("CREATELOCKPATH  proxy lock path=%s pid=%d\n", lockPath, getpid()));
+  return 0;
+}
+
 /*
 ** Create a new VFS file descriptor (stored in memory obtained from
 ** sqlite3_malloc) and open the file named "path" in the file descriptor.
@@ -26155,38 +28623,275 @@ static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
 ** The caller is responsible not only for closing the file descriptor
 ** but also for freeing the memory associated with the file descriptor.
 */
-static int proxyCreateUnixFile(const char *path, unixFile **ppFile) {
-  int fd;
-  int dirfd = -1;
+static int proxyCreateUnixFile(
+    const char *path,        /* path for the new unixFile */
+    unixFile **ppFile,       /* unixFile created and returned by ref */
+    int islockfile           /* if non zero missing dirs will be created */
+) {
+  int fd = -1;
   unixFile *pNew;
   int rc = SQLITE_OK;
+  int openFlags = O_RDWR | O_CREAT;
   sqlite3_vfs dummyVfs;
+  int terrno = 0;
+  UnixUnusedFd *pUnused = NULL;
 
-  fd = open(path, O_RDWR | O_CREAT, SQLITE_DEFAULT_FILE_PERMISSIONS);
+  /* 1. first try to open/create the file
+  ** 2. if that fails, and this is a lock file (not-conch), try creating
+  ** the parent directories and then try again.
+  ** 3. if that fails, try to open the file read-only
+  ** otherwise return BUSY (if lock file) or CANTOPEN for the conch file
+  */
+  pUnused = findReusableFd(path, openFlags);
+  if( pUnused ){
+    fd = pUnused->fd;
+  }else{
+    pUnused = sqlite3_malloc(sizeof(*pUnused));
+    if( !pUnused ){
+      return SQLITE_NOMEM;
+    }
+  }
   if( fd<0 ){
-    return SQLITE_CANTOPEN;
+    fd = robust_open(path, openFlags, 0);
+    terrno = errno;
+    if( fd<0 && errno==ENOENT && islockfile ){
+      if( proxyCreateLockPath(path) == SQLITE_OK ){
+        fd = robust_open(path, openFlags, 0);
+      }
+    }
+  }
+  if( fd<0 ){
+    openFlags = O_RDONLY;
+    fd = robust_open(path, openFlags, 0);
+    terrno = errno;
+  }
+  if( fd<0 ){
+    if( islockfile ){
+      return SQLITE_BUSY;
+    }
+    switch (terrno) {
+      case EACCES:
+        return SQLITE_PERM;
+      case EIO: 
+        return SQLITE_IOERR_LOCK; /* even though it is the conch */
+      default:
+        return SQLITE_CANTOPEN_BKPT;
+    }
   }
   
-  pNew = (unixFile *)sqlite3_malloc(sizeof(unixFile));
+  pNew = (unixFile *)sqlite3_malloc(sizeof(*pNew));
   if( pNew==NULL ){
     rc = SQLITE_NOMEM;
     goto end_create_proxy;
   }
   memset(pNew, 0, sizeof(unixFile));
-
+  pNew->openFlags = openFlags;
+  memset(&dummyVfs, 0, sizeof(dummyVfs));
   dummyVfs.pAppData = (void*)&autolockIoFinder;
-  rc = fillInUnixFile(&dummyVfs, fd, dirfd, (sqlite3_file*)pNew, path, 0, 0);
+  dummyVfs.zName = "dummy";
+  pUnused->fd = fd;
+  pUnused->flags = openFlags;
+  pNew->pUnused = pUnused;
+  
+  rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0);
   if( rc==SQLITE_OK ){
     *ppFile = pNew;
     return SQLITE_OK;
   }
 end_create_proxy:    
-  close(fd); /* silently leak fd if error, we're already in error */
+  robust_close(pNew, fd, __LINE__);
   sqlite3_free(pNew);
+  sqlite3_free(pUnused);
   return rc;
 }
 
-/* takes the conch by taking a shared lock and read the contents conch, if 
+#ifdef SQLITE_TEST
+/* simulate multiple hosts by creating unique hostid file paths */
+SQLITE_API int sqlite3_hostid_num = 0;
+#endif
+
+#define PROXY_HOSTIDLEN    16  /* conch file host id length */
+
+/* Not always defined in the headers as it ought to be */
+extern int gethostuuid(uuid_t id, const struct timespec *wait);
+
+/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN 
+** bytes of writable memory.
+*/
+static int proxyGetHostID(unsigned char *pHostID, int *pError){
+  assert(PROXY_HOSTIDLEN == sizeof(uuid_t));
+  memset(pHostID, 0, PROXY_HOSTIDLEN);
+#if defined(__MAX_OS_X_VERSION_MIN_REQUIRED)\
+               && __MAC_OS_X_VERSION_MIN_REQUIRED<1050
+  {
+    static const struct timespec timeout = {1, 0}; /* 1 sec timeout */
+    if( gethostuuid(pHostID, &timeout) ){
+      int err = errno;
+      if( pError ){
+        *pError = err;
+      }
+      return SQLITE_IOERR;
+    }
+  }
+#else
+  UNUSED_PARAMETER(pError);
+#endif
+#ifdef SQLITE_TEST
+  /* simulate multiple hosts by creating unique hostid file paths */
+  if( sqlite3_hostid_num != 0){
+    pHostID[0] = (char)(pHostID[0] + (char)(sqlite3_hostid_num & 0xFF));
+  }
+#endif
+  
+  return SQLITE_OK;
+}
+
+/* The conch file contains the header, host id and lock file path
+ */
+#define PROXY_CONCHVERSION 2   /* 1-byte header, 16-byte host id, path */
+#define PROXY_HEADERLEN    1   /* conch file header length */
+#define PROXY_PATHINDEX    (PROXY_HEADERLEN+PROXY_HOSTIDLEN)
+#define PROXY_MAXCONCHLEN  (PROXY_HEADERLEN+PROXY_HOSTIDLEN+MAXPATHLEN)
+
+/* 
+** Takes an open conch file, copies the contents to a new path and then moves 
+** it back.  The newly created file's file descriptor is assigned to the
+** conch file structure and finally the original conch file descriptor is 
+** closed.  Returns zero if successful.
+*/
+static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; 
+  unixFile *conchFile = pCtx->conchFile;
+  char tPath[MAXPATHLEN];
+  char buf[PROXY_MAXCONCHLEN];
+  char *cPath = pCtx->conchFilePath;
+  size_t readLen = 0;
+  size_t pathLen = 0;
+  char errmsg[64] = "";
+  int fd = -1;
+  int rc = -1;
+  UNUSED_PARAMETER(myHostID);
+
+  /* create a new path by replace the trailing '-conch' with '-break' */
+  pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
+  if( pathLen>MAXPATHLEN || pathLen<6 || 
+     (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){
+    sqlite3_snprintf(sizeof(errmsg),errmsg,"path error (len %d)",(int)pathLen);
+    goto end_breaklock;
+  }
+  /* read the conch content */
+  readLen = osPread(conchFile->h, buf, PROXY_MAXCONCHLEN, 0);
+  if( readLen<PROXY_PATHINDEX ){
+    sqlite3_snprintf(sizeof(errmsg),errmsg,"read error (len %d)",(int)readLen);
+    goto end_breaklock;
+  }
+  /* write it out to the temporary break file */
+  fd = robust_open(tPath, (O_RDWR|O_CREAT|O_EXCL), 0);
+  if( fd<0 ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "create failed (%d)", errno);
+    goto end_breaklock;
+  }
+  if( osPwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "write failed (%d)", errno);
+    goto end_breaklock;
+  }
+  if( rename(tPath, cPath) ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "rename failed (%d)", errno);
+    goto end_breaklock;
+  }
+  rc = 0;
+  fprintf(stderr, "broke stale lock on %s\n", cPath);
+  robust_close(pFile, conchFile->h, __LINE__);
+  conchFile->h = fd;
+  conchFile->openFlags = O_RDWR | O_CREAT;
+
+end_breaklock:
+  if( rc ){
+    if( fd>=0 ){
+      osUnlink(tPath);
+      robust_close(pFile, fd, __LINE__);
+    }
+    fprintf(stderr, "failed to break stale lock on %s, %s\n", cPath, errmsg);
+  }
+  return rc;
+}
+
+/* Take the requested lock on the conch file and break a stale lock if the 
+** host id matches.
+*/
+static int proxyConchLock(unixFile *pFile, uuid_t myHostID, int lockType){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; 
+  unixFile *conchFile = pCtx->conchFile;
+  int rc = SQLITE_OK;
+  int nTries = 0;
+  struct timespec conchModTime;
+  
+  memset(&conchModTime, 0, sizeof(conchModTime));
+  do {
+    rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+    nTries ++;
+    if( rc==SQLITE_BUSY ){
+      /* If the lock failed (busy):
+       * 1st try: get the mod time of the conch, wait 0.5s and try again. 
+       * 2nd try: fail if the mod time changed or host id is different, wait 
+       *           10 sec and try again
+       * 3rd try: break the lock unless the mod time has changed.
+       */
+      struct stat buf;
+      if( osFstat(conchFile->h, &buf) ){
+        pFile->lastErrno = errno;
+        return SQLITE_IOERR_LOCK;
+      }
+      
+      if( nTries==1 ){
+        conchModTime = buf.st_mtimespec;
+        usleep(500000); /* wait 0.5 sec and try the lock again*/
+        continue;  
+      }
+
+      assert( nTries>1 );
+      if( conchModTime.tv_sec != buf.st_mtimespec.tv_sec || 
+         conchModTime.tv_nsec != buf.st_mtimespec.tv_nsec ){
+        return SQLITE_BUSY;
+      }
+      
+      if( nTries==2 ){  
+        char tBuf[PROXY_MAXCONCHLEN];
+        int len = osPread(conchFile->h, tBuf, PROXY_MAXCONCHLEN, 0);
+        if( len<0 ){
+          pFile->lastErrno = errno;
+          return SQLITE_IOERR_LOCK;
+        }
+        if( len>PROXY_PATHINDEX && tBuf[0]==(char)PROXY_CONCHVERSION){
+          /* don't break the lock if the host id doesn't match */
+          if( 0!=memcmp(&tBuf[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN) ){
+            return SQLITE_BUSY;
+          }
+        }else{
+          /* don't break the lock on short read or a version mismatch */
+          return SQLITE_BUSY;
+        }
+        usleep(10000000); /* wait 10 sec and try the lock again */
+        continue; 
+      }
+      
+      assert( nTries==3 );
+      if( 0==proxyBreakConchLock(pFile, myHostID) ){
+        rc = SQLITE_OK;
+        if( lockType==EXCLUSIVE_LOCK ){
+          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK);          
+        }
+        if( !rc ){
+          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+        }
+      }
+    }
+  } while( rc==SQLITE_BUSY && nTries<3 );
+  
+  return rc;
+}
+
+/* Takes the conch by taking a shared lock and read the contents conch, if 
 ** lockPath is non-NULL, the host ID and lock file path must match.  A NULL 
 ** lockPath means that the lockPath in the conch file will be used if the 
 ** host IDs match, or a new lock path will be generated automatically 
@@ -26195,149 +28900,217 @@ end_create_proxy:
 static int proxyTakeConch(unixFile *pFile){
   proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; 
   
-  if( pCtx->conchHeld>0 ){
+  if( pCtx->conchHeld!=0 ){
     return SQLITE_OK;
   }else{
     unixFile *conchFile = pCtx->conchFile;
-    char testValue[CONCHLEN];
-    char conchValue[CONCHLEN];
+    uuid_t myHostID;
+    int pError = 0;
+    char readBuf[PROXY_MAXCONCHLEN];
     char lockPath[MAXPATHLEN];
-    char *tLockPath = NULL;
+    char *tempLockPath = NULL;
     int rc = SQLITE_OK;
-    int readRc = SQLITE_OK;
-    int syncPerms = 0;
+    int createConch = 0;
+    int hostIdMatch = 0;
+    int readLen = 0;
+    int tryOldLockPath = 0;
+    int forceNewLockPath = 0;
+    
+    OSTRACE(("TAKECONCH  %d for %s pid=%d\n", conchFile->h,
+             (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), getpid()));
 
-    OSTRACE4("TAKECONCH  %d for %s pid=%d\n", conchFile->h,
-             (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), getpid());
-
-    rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK);
-    if( rc==SQLITE_OK ){
-      int pError = 0;
-      memset(testValue, 0, CONCHLEN); /* conch is fixed size */
-      rc = proxyGetHostID(testValue, &pError);
-      if( (rc&0xff)==SQLITE_IOERR ){
-        pFile->lastErrno = pError;
-      }
-      if( pCtx->lockProxyPath ){
-        strlcpy(&testValue[HOSTIDLEN], pCtx->lockProxyPath, MAXPATHLEN);
-      }
+    rc = proxyGetHostID(myHostID, &pError);
+    if( (rc&0xff)==SQLITE_IOERR ){
+      pFile->lastErrno = pError;
+      goto end_takeconch;
     }
+    rc = proxyConchLock(pFile, myHostID, SHARED_LOCK);
     if( rc!=SQLITE_OK ){
       goto end_takeconch;
     }
-    
-    readRc = unixRead((sqlite3_file *)conchFile, conchValue, CONCHLEN, 0);
-    if( readRc!=SQLITE_IOERR_SHORT_READ ){
-      if( readRc!=SQLITE_OK ){
-        if( (rc&0xff)==SQLITE_IOERR ){
-          pFile->lastErrno = conchFile->lastErrno;
+    /* read the existing conch file */
+    readLen = seekAndRead((unixFile*)conchFile, 0, readBuf, PROXY_MAXCONCHLEN);
+    if( readLen<0 ){
+      /* I/O error: lastErrno set by seekAndRead */
+      pFile->lastErrno = conchFile->lastErrno;
+      rc = SQLITE_IOERR_READ;
+      goto end_takeconch;
+    }else if( readLen<=(PROXY_HEADERLEN+PROXY_HOSTIDLEN) || 
+             readBuf[0]!=(char)PROXY_CONCHVERSION ){
+      /* a short read or version format mismatch means we need to create a new 
+      ** conch file. 
+      */
+      createConch = 1;
+    }
+    /* if the host id matches and the lock path already exists in the conch
+    ** we'll try to use the path there, if we can't open that path, we'll 
+    ** retry with a new auto-generated path 
+    */
+    do { /* in case we need to try again for an :auto: named lock file */
+
+      if( !createConch && !forceNewLockPath ){
+        hostIdMatch = !memcmp(&readBuf[PROXY_HEADERLEN], myHostID, 
+                                  PROXY_HOSTIDLEN);
+        /* if the conch has data compare the contents */
+        if( !pCtx->lockProxyPath ){
+          /* for auto-named local lock file, just check the host ID and we'll
+           ** use the local lock file path that's already in there
+           */
+          if( hostIdMatch ){
+            size_t pathLen = (readLen - PROXY_PATHINDEX);
+            
+            if( pathLen>=MAXPATHLEN ){
+              pathLen=MAXPATHLEN-1;
+            }
+            memcpy(lockPath, &readBuf[PROXY_PATHINDEX], pathLen);
+            lockPath[pathLen] = 0;
+            tempLockPath = lockPath;
+            tryOldLockPath = 1;
+            /* create a copy of the lock path if the conch is taken */
+            goto end_takeconch;
+          }
+        }else if( hostIdMatch
+               && !strncmp(pCtx->lockProxyPath, &readBuf[PROXY_PATHINDEX],
+                           readLen-PROXY_PATHINDEX)
+        ){
+          /* conch host and lock path match */
+          goto end_takeconch; 
         }
-        rc = readRc;
+      }
+      
+      /* if the conch isn't writable and doesn't match, we can't take it */
+      if( (conchFile->openFlags&O_RDWR) == 0 ){
+        rc = SQLITE_BUSY;
         goto end_takeconch;
       }
-      /* if the conch has data compare the contents */
+      
+      /* either the conch didn't match or we need to create a new one */
       if( !pCtx->lockProxyPath ){
-        /* for auto-named local lock file, just check the host ID and we'll
-         ** use the local lock file path that's already in there */
-        if( !memcmp(testValue, conchValue, HOSTIDLEN) ){
-          tLockPath = (char *)&conchValue[HOSTIDLEN];
-          goto end_takeconch;
-        }
-      }else{
-        /* we've got the conch if conchValue matches our path and host ID */
-        if( !memcmp(testValue, conchValue, CONCHLEN) ){
-          goto end_takeconch;
-        }
+        proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN);
+        tempLockPath = lockPath;
+        /* create a copy of the lock path _only_ if the conch is taken */
       }
-    }else{
-      /* a short read means we're "creating" the conch (even though it could 
-      ** have been user-intervention), if we acquire the exclusive lock,
-      ** we'll try to match the current on-disk permissions of the database
+      
+      /* update conch with host and path (this will fail if other process
+      ** has a shared lock already), if the host id matches, use the big
+      ** stick.
       */
-      syncPerms = 1;
-    }
-    
-    /* either conch was emtpy or didn't match */
-    if( !pCtx->lockProxyPath ){
-      proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN);
-      tLockPath = lockPath;
-      strlcpy(&testValue[HOSTIDLEN], lockPath, MAXPATHLEN);
-    }
-    
-    /* update conch with host and path (this will fail if other process
-     ** has a shared lock already) */
-    rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, EXCLUSIVE_LOCK);
-    if( rc==SQLITE_OK ){
-      rc = unixWrite((sqlite3_file *)conchFile, testValue, CONCHLEN, 0);
-      if( rc==SQLITE_OK && syncPerms ){
-        struct stat buf;
-        int err = fstat(pFile->h, &buf);
-        if( err==0 ){
-          /* try to match the database file permissions, ignore failure */
-#ifndef SQLITE_PROXY_DEBUG
-          fchmod(conchFile->h, buf.st_mode);
-#else
-          if( fchmod(conchFile->h, buf.st_mode)!=0 ){
-            int code = errno;
-            fprintf(stderr, "fchmod %o FAILED with %d %s\n",
-                             buf.st_mode, code, strerror(code));
-          } else {
-            fprintf(stderr, "fchmod %o SUCCEDED\n",buf.st_mode);
-          }
-        }else{
-          int code = errno;
-          fprintf(stderr, "STAT FAILED[%d] with %d %s\n", 
-                          err, code, strerror(code));
-#endif
+      futimes(conchFile->h, NULL);
+      if( hostIdMatch && !createConch ){
+        if( conchFile->pInode && conchFile->pInode->nShared>1 ){
+          /* We are trying for an exclusive lock but another thread in this
+           ** same process is still holding a shared lock. */
+          rc = SQLITE_BUSY;
+        } else {          
+          rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
         }
-      }
-    }
-    conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
-  
-end_takeconch:
-    OSTRACE2("TRANSPROXY: CLOSE  %d\n", pFile->h);
-    if( rc==SQLITE_OK && pFile->openFlags ){
-      if( pFile->h>=0 ){
-#ifdef STRICT_CLOSE_ERROR
-        if( close(pFile->h) ){
-          pFile->lastErrno = errno;
-          return SQLITE_IOERR_CLOSE;
-        }
-#else
-        close(pFile->h); /* silently leak fd if fail */
-#endif
-      }
-      pFile->h = -1;
-      int fd = open(pCtx->dbPath, pFile->openFlags,
-                    SQLITE_DEFAULT_FILE_PERMISSIONS);
-      OSTRACE2("TRANSPROXY: OPEN  %d\n", fd);
-      if( fd>=0 ){
-        pFile->h = fd;
       }else{
-        rc=SQLITE_CANTOPEN; /* SQLITE_BUSY? proxyTakeConch called
-                               during locking */
+        rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, EXCLUSIVE_LOCK);
       }
-    }
-    if( rc==SQLITE_OK && !pCtx->lockProxy ){
-      char *path = tLockPath ? tLockPath : pCtx->lockProxyPath;
-      /* ACS: Need to make a copy of path sometimes */
-      rc = proxyCreateUnixFile(path, &pCtx->lockProxy);
-    }
-    if( rc==SQLITE_OK ){
-      pCtx->conchHeld = 1;
-
-      if( tLockPath ){
-        pCtx->lockProxyPath = sqlite3DbStrDup(0, tLockPath);
-        if( pCtx->lockProxy->pMethod == &afpIoMethods ){
-          ((afpLockingContext *)pCtx->lockProxy->lockingContext)->dbPath =
-                     pCtx->lockProxyPath;
+      if( rc==SQLITE_OK ){
+        char writeBuffer[PROXY_MAXCONCHLEN];
+        int writeSize = 0;
+        
+        writeBuffer[0] = (char)PROXY_CONCHVERSION;
+        memcpy(&writeBuffer[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN);
+        if( pCtx->lockProxyPath!=NULL ){
+          strlcpy(&writeBuffer[PROXY_PATHINDEX], pCtx->lockProxyPath, MAXPATHLEN);
+        }else{
+          strlcpy(&writeBuffer[PROXY_PATHINDEX], tempLockPath, MAXPATHLEN);
+        }
+        writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);
+        robust_ftruncate(conchFile->h, writeSize);
+        rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);
+        fsync(conchFile->h);
+        /* If we created a new conch file (not just updated the contents of a 
+         ** valid conch file), try to match the permissions of the database 
+         */
+        if( rc==SQLITE_OK && createConch ){
+          struct stat buf;
+          int err = osFstat(pFile->h, &buf);
+          if( err==0 ){
+            mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP |
+                                        S_IROTH|S_IWOTH);
+            /* try to match the database file R/W permissions, ignore failure */
+#ifndef SQLITE_PROXY_DEBUG
+            osFchmod(conchFile->h, cmode);
+#else
+            do{
+              rc = osFchmod(conchFile->h, cmode);
+            }while( rc==(-1) && errno==EINTR );
+            if( rc!=0 ){
+              int code = errno;
+              fprintf(stderr, "fchmod %o FAILED with %d %s\n",
+                      cmode, code, strerror(code));
+            } else {
+              fprintf(stderr, "fchmod %o SUCCEDED\n",cmode);
+            }
+          }else{
+            int code = errno;
+            fprintf(stderr, "STAT FAILED[%d] with %d %s\n", 
+                    err, code, strerror(code));
+#endif
+          }
         }
       }
-    } else {
-      conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
-    }
-    OSTRACE3("TAKECONCH  %d %s\n", conchFile->h, rc==SQLITE_OK?"ok":"failed");
-    return rc;
+      conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
+      
+    end_takeconch:
+      OSTRACE(("TRANSPROXY: CLOSE  %d\n", pFile->h));
+      if( rc==SQLITE_OK && pFile->openFlags ){
+        int fd;
+        if( pFile->h>=0 ){
+          robust_close(pFile, pFile->h, __LINE__);
+        }
+        pFile->h = -1;
+        fd = robust_open(pCtx->dbPath, pFile->openFlags, 0);
+        OSTRACE(("TRANSPROXY: OPEN  %d\n", fd));
+        if( fd>=0 ){
+          pFile->h = fd;
+        }else{
+          rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called
+           during locking */
+        }
+      }
+      if( rc==SQLITE_OK && !pCtx->lockProxy ){
+        char *path = tempLockPath ? tempLockPath : pCtx->lockProxyPath;
+        rc = proxyCreateUnixFile(path, &pCtx->lockProxy, 1);
+        if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && tryOldLockPath ){
+          /* we couldn't create the proxy lock file with the old lock file path
+           ** so try again via auto-naming 
+           */
+          forceNewLockPath = 1;
+          tryOldLockPath = 0;
+          continue; /* go back to the do {} while start point, try again */
+        }
+      }
+      if( rc==SQLITE_OK ){
+        /* Need to make a copy of path if we extracted the value
+         ** from the conch file or the path was allocated on the stack
+         */
+        if( tempLockPath ){
+          pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath);
+          if( !pCtx->lockProxyPath ){
+            rc = SQLITE_NOMEM;
+          }
+        }
+      }
+      if( rc==SQLITE_OK ){
+        pCtx->conchHeld = 1;
+        
+        if( pCtx->lockProxy->pMethod == &afpIoMethods ){
+          afpLockingContext *afpCtx;
+          afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext;
+          afpCtx->dbPath = pCtx->lockProxyPath;
+        }
+      } else {
+        conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
+      }
+      OSTRACE(("TAKECONCH  %d %s\n", conchFile->h,
+               rc==SQLITE_OK?"ok":"failed"));
+      return rc;
+    } while (1); /* in case we need to retry the :auto: lock file - 
+                 ** we should never get here except via the 'continue' call. */
   }
 }
 
@@ -26345,19 +29118,21 @@ end_takeconch:
 ** If pFile holds a lock on a conch file, then release that lock.
 */
 static int proxyReleaseConch(unixFile *pFile){
-  int rc;                     /* Subroutine return code */
+  int rc = SQLITE_OK;         /* Subroutine return code */
   proxyLockingContext *pCtx;  /* The locking context for the proxy lock */
   unixFile *conchFile;        /* Name of the conch file */
 
   pCtx = (proxyLockingContext *)pFile->lockingContext;
   conchFile = pCtx->conchFile;
-  OSTRACE4("RELEASECONCH  %d for %s pid=%d\n", conchFile->h,
+  OSTRACE(("RELEASECONCH  %d for %s pid=%d\n", conchFile->h,
            (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), 
-           getpid());
+           getpid()));
+  if( pCtx->conchHeld>0 ){
+    rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
+  }
   pCtx->conchHeld = 0;
-  rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
-  OSTRACE3("RELEASECONCH  %d %s\n", conchFile->h,
-           (rc==SQLITE_OK ? "ok" : "failed"));
+  OSTRACE(("RELEASECONCH  %d %s\n", conchFile->h,
+           (rc==SQLITE_OK ? "ok" : "failed")));
   return rc;
 }
 
@@ -26414,7 +29189,7 @@ static int switchLockProxyPath(unixFile *pFile, const char *path) {
   char *oldPath = pCtx->lockProxyPath;
   int rc = SQLITE_OK;
 
-  if( pFile->locktype!=NO_LOCK ){
+  if( pFile->eFileLock!=NO_LOCK ){
     return SQLITE_BUSY;
   }  
 
@@ -26451,8 +29226,8 @@ static int proxyGetDbPathForUnixFile(unixFile *pFile, char *dbPath){
     /* afp style keeps a reference to the db path in the filePath field 
     ** of the struct */
     assert( (int)strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
-    strcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath);
-  }else
+    strlcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath, MAXPATHLEN);
+  } else
 #endif
   if( pFile->pMethod == &dotlockIoMethods ){
     /* dot lock style uses the locking context to store the dot lock
@@ -26462,7 +29237,7 @@ static int proxyGetDbPathForUnixFile(unixFile *pFile, char *dbPath){
   }else{
     /* all other styles use the locking context to store the db file path */
     assert( strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
-    strcpy(dbPath, (char *)pFile->lockingContext);
+    strlcpy(dbPath, (char *)pFile->lockingContext, MAXPATHLEN);
   }
   return SQLITE_OK;
 }
@@ -26481,7 +29256,7 @@ static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
   char *lockPath=NULL;
   int rc = SQLITE_OK;
   
-  if( pFile->locktype!=NO_LOCK ){
+  if( pFile->eFileLock!=NO_LOCK ){
     return SQLITE_BUSY;
   }
   proxyGetDbPathForUnixFile(pFile, dbPath);
@@ -26491,8 +29266,8 @@ static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
     lockPath=(char *)path;
   }
   
-  OSTRACE4("TRANSPROXY  %d for %s pid=%d\n", pFile->h,
-           (lockPath ? lockPath : ":auto:"), getpid());
+  OSTRACE(("TRANSPROXY  %d for %s pid=%d\n", pFile->h,
+           (lockPath ? lockPath : ":auto:"), getpid()));
 
   pCtx = sqlite3_malloc( sizeof(*pCtx) );
   if( pCtx==0 ){
@@ -26502,32 +29277,58 @@ static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
 
   rc = proxyCreateConchPathname(dbPath, &pCtx->conchFilePath);
   if( rc==SQLITE_OK ){
-    rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile);
+    rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile, 0);
+    if( rc==SQLITE_CANTOPEN && ((pFile->openFlags&O_RDWR) == 0) ){
+      /* if (a) the open flags are not O_RDWR, (b) the conch isn't there, and
+      ** (c) the file system is read-only, then enable no-locking access.
+      ** Ugh, since O_RDONLY==0x0000 we test for !O_RDWR since unixOpen asserts
+      ** that openFlags will have only one of O_RDONLY or O_RDWR.
+      */
+      struct statfs fsInfo;
+      struct stat conchInfo;
+      int goLockless = 0;
+
+      if( osStat(pCtx->conchFilePath, &conchInfo) == -1 ) {
+        int err = errno;
+        if( (err==ENOENT) && (statfs(dbPath, &fsInfo) != -1) ){
+          goLockless = (fsInfo.f_flags&MNT_RDONLY) == MNT_RDONLY;
+        }
+      }
+      if( goLockless ){
+        pCtx->conchHeld = -1; /* read only FS/ lockless */
+        rc = SQLITE_OK;
+      }
+    }
   }  
   if( rc==SQLITE_OK && lockPath ){
     pCtx->lockProxyPath = sqlite3DbStrDup(0, lockPath);
   }
 
+  if( rc==SQLITE_OK ){
+    pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
+    if( pCtx->dbPath==NULL ){
+      rc = SQLITE_NOMEM;
+    }
+  }
   if( rc==SQLITE_OK ){
     /* all memory is allocated, proxys are created and assigned, 
     ** switch the locking context and pMethod then return.
     */
-    pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
     pCtx->oldLockingContext = pFile->lockingContext;
     pFile->lockingContext = pCtx;
     pCtx->pOldMethod = pFile->pMethod;
     pFile->pMethod = &proxyIoMethods;
   }else{
     if( pCtx->conchFile ){ 
-      rc = pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
-      if( rc ) return rc;
+      pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
       sqlite3_free(pCtx->conchFile);
     }
+    sqlite3DbFree(0, pCtx->lockProxyPath);
     sqlite3_free(pCtx->conchFilePath); 
     sqlite3_free(pCtx);
   }
-  OSTRACE3("TRANSPROXY  %d %s\n", pFile->h,
-           (rc==SQLITE_OK ? "ok" : "failed"));
+  OSTRACE(("TRANSPROXY  %d %s\n", pFile->h,
+           (rc==SQLITE_OK ? "ok" : "failed")));
   return rc;
 }
 
@@ -26611,14 +29412,18 @@ static int proxyCheckReservedLock(sqlite3_file *id, int *pResOut) {
   int rc = proxyTakeConch(pFile);
   if( rc==SQLITE_OK ){
     proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
-    unixFile *proxy = pCtx->lockProxy;
-    return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut);
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut);
+    }else{ /* conchHeld < 0 is lockless */
+      pResOut=0;
+    }
   }
   return rc;
 }
 
 /*
-** Lock the file with the lock specified by parameter locktype - one
+** Lock the file with the lock specified by parameter eFileLock - one
 ** of the following:
 **
 **     (1) SHARED_LOCK
@@ -26641,34 +29446,42 @@ static int proxyCheckReservedLock(sqlite3_file *id, int *pResOut) {
 ** This routine will only increase a lock.  Use the sqlite3OsUnlock()
 ** routine to lower a locking level.
 */
-static int proxyLock(sqlite3_file *id, int locktype) {
+static int proxyLock(sqlite3_file *id, int eFileLock) {
   unixFile *pFile = (unixFile*)id;
   int rc = proxyTakeConch(pFile);
   if( rc==SQLITE_OK ){
     proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
-    unixFile *proxy = pCtx->lockProxy;
-    rc = proxy->pMethod->xLock((sqlite3_file*)proxy, locktype);
-    pFile->locktype = proxy->locktype;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      rc = proxy->pMethod->xLock((sqlite3_file*)proxy, eFileLock);
+      pFile->eFileLock = proxy->eFileLock;
+    }else{
+      /* conchHeld < 0 is lockless */
+    }
   }
   return rc;
 }
 
 
 /*
-** Lower the locking level on file descriptor pFile to locktype.  locktype
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
 */
-static int proxyUnlock(sqlite3_file *id, int locktype) {
+static int proxyUnlock(sqlite3_file *id, int eFileLock) {
   unixFile *pFile = (unixFile*)id;
   int rc = proxyTakeConch(pFile);
   if( rc==SQLITE_OK ){
     proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
-    unixFile *proxy = pCtx->lockProxy;
-    rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, locktype);
-    pFile->locktype = proxy->locktype;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, eFileLock);
+      pFile->eFileLock = proxy->eFileLock;
+    }else{
+      /* conchHeld < 0 is lockless */
+    }
   }
   return rc;
 }
@@ -26701,9 +29514,9 @@ static int proxyClose(sqlite3_file *id) {
       if( rc ) return rc;
       sqlite3_free(conchFile);
     }
-    sqlite3_free(pCtx->lockProxyPath);
+    sqlite3DbFree(0, pCtx->lockProxyPath);
     sqlite3_free(pCtx->conchFilePath);
-    sqlite3_free(pCtx->dbPath);
+    sqlite3DbFree(0, pCtx->dbPath);
     /* restore the original locking context and pMethod then close it */
     pFile->lockingContext = pCtx->oldLockingContext;
     pFile->pMethod = pCtx->pOldMethod;
@@ -26760,7 +29573,7 @@ SQLITE_API int sqlite3_os_init(void){
   ** that filesystem time.
   */
   #define UNIXVFS(VFSNAME, FINDER) {                        \
-    1,                    /* iVersion */                    \
+    3,                    /* iVersion */                    \
     sizeof(unixFile),     /* szOsFile */                    \
     MAX_PATHNAME,         /* mxPathname */                  \
     0,                    /* pNext */                       \
@@ -26777,7 +29590,11 @@ SQLITE_API int sqlite3_os_init(void){
     unixRandomness,       /* xRandomness */                 \
     unixSleep,            /* xSleep */                      \
     unixCurrentTime,      /* xCurrentTime */                \
-    unixGetLastError      /* xGetLastError */               \
+    unixGetLastError,     /* xGetLastError */               \
+    unixCurrentTimeInt64, /* xCurrentTimeInt64 */           \
+    unixSetSystemCall,    /* xSetSystemCall */              \
+    unixGetSystemCall,    /* xGetSystemCall */              \
+    unixNextSystemCall,   /* xNextSystemCall */             \
   }
 
   /*
@@ -26788,27 +29605,35 @@ SQLITE_API int sqlite3_os_init(void){
   ** array cannot be const.
   */
   static sqlite3_vfs aVfs[] = {
-#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+#if SQLITE_ENABLE_LOCKING_STYLE && (OS_VXWORKS || defined(__APPLE__))
     UNIXVFS("unix",          autolockIoFinder ),
 #else
     UNIXVFS("unix",          posixIoFinder ),
 #endif
     UNIXVFS("unix-none",     nolockIoFinder ),
     UNIXVFS("unix-dotfile",  dotlockIoFinder ),
+    UNIXVFS("unix-excl",     posixIoFinder ),
 #if OS_VXWORKS
     UNIXVFS("unix-namedsem", semIoFinder ),
 #endif
 #if SQLITE_ENABLE_LOCKING_STYLE
     UNIXVFS("unix-posix",    posixIoFinder ),
+#if !OS_VXWORKS
     UNIXVFS("unix-flock",    flockIoFinder ),
 #endif
+#endif
 #if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
     UNIXVFS("unix-afp",      afpIoFinder ),
+    UNIXVFS("unix-nfs",      nfsIoFinder ),
     UNIXVFS("unix-proxy",    proxyIoFinder ),
 #endif
   };
   unsigned int i;          /* Loop counter */
 
+  /* Double-check that the aSyscall[] array has been constructed
+  ** correctly.  See ticket [bb3a86e890c8e96ab] */
+  assert( ArraySize(aSyscall)==22 );
+
   /* Register all VFSes defined in the aVfs[] array */
   for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
     sqlite3_vfs_register(&aVfs[i], i==0);
@@ -26843,52 +29668,14 @@ SQLITE_API int sqlite3_os_end(void){
 **
 ******************************************************************************
 **
-** This file contains code that is specific to windows.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+** This file contains code that is specific to Windows.
 */
-#if SQLITE_OS_WIN               /* This file is used for windows only */
-
-
-/*
-** A Note About Memory Allocation:
-**
-** This driver uses malloc()/free() directly rather than going through
-** the SQLite-wrappers sqlite3_malloc()/sqlite3_free().  Those wrappers
-** are designed for use on embedded systems where memory is scarce and
-** malloc failures happen frequently.  Win32 does not typically run on
-** embedded systems, and when it does the developers normally have bigger
-** problems to worry about than running out of memory.  So there is not
-** a compelling need to use the wrappers.
-**
-** But there is a good reason to not use the wrappers.  If we use the
-** wrappers then we will get simulated malloc() failures within this
-** driver.  And that causes all kinds of problems for our tests.  We
-** could enhance SQLite to deal with simulated malloc failures within
-** the OS driver, but the code to deal with those failure would not
-** be exercised on Linux (which does not need to malloc() in the driver)
-** and so we would have difficulty writing coverage tests for that
-** code.  Better to leave the code out, we think.
-**
-** The point of this discussion is as follows:  When creating a new
-** OS layer for an embedded system, if you use this file as an example,
-** avoid the use of malloc()/free().  Those routines work ok on windows
-** desktops but not so well in embedded systems.
-*/
-
-#include <winbase.h>
+#if SQLITE_OS_WIN               /* This file is used for Windows only */
 
 #ifdef __CYGWIN__
 # include <sys/cygwin.h>
 #endif
 
-/*
-** Macros used to determine whether or not to use threads.
-*/
-#if defined(THREADSAFE) && THREADSAFE
-# define SQLITE_W32_THREADS 1
-#endif
-
 /*
 ** Include code that is common to all os_*.c files
 */
@@ -26912,8 +29699,6 @@ SQLITE_API int sqlite3_os_end(void){
 **
 ** This file should be #included by the os_*.c files only.  It is not a
 ** general purpose header file.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _OS_COMMON_H_
 #define _OS_COMMON_H_
@@ -26927,34 +29712,14 @@ SQLITE_API int sqlite3_os_end(void){
 # error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
 #endif
 
-
-/*
- * When testing, this global variable stores the location of the
- * pending-byte in the database file.
- */
-#ifdef SQLITE_TEST
-SQLITE_API unsigned int sqlite3_pending_byte = 0x40000000;
-#endif
-
-#ifdef SQLITE_DEBUG
-SQLITE_PRIVATE int sqlite3OSTrace = 0;
-#define OSTRACE1(X)         if( sqlite3OSTrace ) sqlite3DebugPrintf(X)
-#define OSTRACE2(X,Y)       if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y)
-#define OSTRACE3(X,Y,Z)     if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z)
-#define OSTRACE4(X,Y,Z,A)   if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A)
-#define OSTRACE5(X,Y,Z,A,B) if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A,B)
-#define OSTRACE6(X,Y,Z,A,B,C) \
-    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
-#define OSTRACE7(X,Y,Z,A,B,C,D) \
-    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+# ifndef SQLITE_DEBUG_OS_TRACE
+#   define SQLITE_DEBUG_OS_TRACE 0
+# endif
+  int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
+# define OSTRACE(X)          if( sqlite3OSTrace ) sqlite3DebugPrintf X
 #else
-#define OSTRACE1(X)
-#define OSTRACE2(X,Y)
-#define OSTRACE3(X,Y,Z)
-#define OSTRACE4(X,Y,Z,A)
-#define OSTRACE5(X,Y,Z,A,B)
-#define OSTRACE6(X,Y,Z,A,B,C)
-#define OSTRACE7(X,Y,Z,A,B,C,D)
+# define OSTRACE(X)
 #endif
 
 /*
@@ -26983,8 +29748,6 @@ SQLITE_PRIVATE int sqlite3OSTrace = 0;
 **
 ** This file contains inline asm code for retrieving "high-performance"
 ** counters for x86 class CPUs.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _HWTIME_H_
 #define _HWTIME_H_
@@ -27127,18 +29890,31 @@ SQLITE_API int sqlite3_open_file_count = 0;
 /************** Continuing where we left off in os_win.c *********************/
 
 /*
-** Some microsoft compilers lack this definition.
+** Macro to find the minimum of two numeric values.
+*/
+#ifndef MIN
+# define MIN(x,y) ((x)<(y)?(x):(y))
+#endif
+
+/*
+** Some Microsoft compilers lack this definition.
 */
 #ifndef INVALID_FILE_ATTRIBUTES
 # define INVALID_FILE_ATTRIBUTES ((DWORD)-1) 
 #endif
 
-/*
-** Determine if we are dealing with WindowsCE - which has a much
-** reduced API.
-*/
-#if SQLITE_OS_WINCE
-# define AreFileApisANSI() 1
+#ifndef FILE_FLAG_MASK
+# define FILE_FLAG_MASK          (0xFF3C0000)
+#endif
+
+#ifndef FILE_ATTRIBUTE_MASK
+# define FILE_ATTRIBUTE_MASK     (0x0003FFF7)
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+/* Forward references */
+typedef struct winShm winShm;           /* A connection to shared-memory */
+typedef struct winShmNode winShmNode;   /* A region of shared-memory */
 #endif
 
 /*
@@ -27160,12 +29936,20 @@ typedef struct winceLock {
 */
 typedef struct winFile winFile;
 struct winFile {
-  const sqlite3_io_methods *pMethod;/* Must be first */
+  const sqlite3_io_methods *pMethod; /*** Must be first ***/
+  sqlite3_vfs *pVfs;      /* The VFS used to open this file */
   HANDLE h;               /* Handle for accessing the file */
-  unsigned char locktype; /* Type of lock currently held on this file */
+  u8 locktype;            /* Type of lock currently held on this file */
   short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
+  u8 ctrlFlags;           /* Flags.  See WINFILE_* below */
+  DWORD lastErrno;        /* The Windows errno from the last I/O error */
+#ifndef SQLITE_OMIT_WAL
+  winShm *pShm;           /* Instance of shared memory on this file */
+#endif
+  const char *zPath;      /* Full pathname of this file */
+  int szChunk;            /* Chunk size configured by FCNTL_CHUNK_SIZE */
 #if SQLITE_OS_WINCE
-  WCHAR *zDeleteOnClose;  /* Name of file to delete when closing */
+  LPWSTR zDeleteOnClose;  /* Name of file to delete when closing */
   HANDLE hMutex;          /* Mutex used to control access to shared lock */  
   HANDLE hShared;         /* Shared memory segment used for locking */
   winceLock local;        /* Locks obtained by this instance of winFile */
@@ -27173,14 +29957,132 @@ struct winFile {
 #endif
 };
 
+/*
+** Allowed values for winFile.ctrlFlags
+*/
+#define WINFILE_PERSIST_WAL     0x04   /* Persistent WAL mode */
+#define WINFILE_PSOW            0x10   /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+
+/*
+ * The size of the buffer used by sqlite3_win32_write_debug().
+ */
+#ifndef SQLITE_WIN32_DBG_BUF_SIZE
+#  define SQLITE_WIN32_DBG_BUF_SIZE   ((int)(4096-sizeof(DWORD)))
+#endif
+
+/*
+ * The value used with sqlite3_win32_set_directory() to specify that
+ * the data directory should be changed.
+ */
+#ifndef SQLITE_WIN32_DATA_DIRECTORY_TYPE
+#  define SQLITE_WIN32_DATA_DIRECTORY_TYPE (1)
+#endif
+
+/*
+ * The value used with sqlite3_win32_set_directory() to specify that
+ * the temporary directory should be changed.
+ */
+#ifndef SQLITE_WIN32_TEMP_DIRECTORY_TYPE
+#  define SQLITE_WIN32_TEMP_DIRECTORY_TYPE (2)
+#endif
+
+/*
+ * If compiled with SQLITE_WIN32_MALLOC on Windows, we will use the
+ * various Win32 API heap functions instead of our own.
+ */
+#ifdef SQLITE_WIN32_MALLOC
+
+/*
+ * If this is non-zero, an isolated heap will be created by the native Win32
+ * allocator subsystem; otherwise, the default process heap will be used.  This
+ * setting has no effect when compiling for WinRT.  By default, this is enabled
+ * and an isolated heap will be created to store all allocated data.
+ *
+ ******************************************************************************
+ * WARNING: It is important to note that when this setting is non-zero and the
+ *          winMemShutdown function is called (e.g. by the sqlite3_shutdown
+ *          function), all data that was allocated using the isolated heap will
+ *          be freed immediately and any attempt to access any of that freed
+ *          data will almost certainly result in an immediate access violation.
+ ******************************************************************************
+ */
+#ifndef SQLITE_WIN32_HEAP_CREATE
+#  define SQLITE_WIN32_HEAP_CREATE    (TRUE)
+#endif
+
+/*
+ * The initial size of the Win32-specific heap.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_INIT_SIZE
+#  define SQLITE_WIN32_HEAP_INIT_SIZE ((SQLITE_DEFAULT_CACHE_SIZE) * \
+                                       (SQLITE_DEFAULT_PAGE_SIZE) + 4194304)
+#endif
+
+/*
+ * The maximum size of the Win32-specific heap.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_MAX_SIZE
+#  define SQLITE_WIN32_HEAP_MAX_SIZE  (0)
+#endif
+
+/*
+ * The extra flags to use in calls to the Win32 heap APIs.  This value may be
+ * zero for the default behavior.
+ */
+#ifndef SQLITE_WIN32_HEAP_FLAGS
+#  define SQLITE_WIN32_HEAP_FLAGS     (0)
+#endif
+
+/*
+** The winMemData structure stores information required by the Win32-specific
+** sqlite3_mem_methods implementation.
+*/
+typedef struct winMemData winMemData;
+struct winMemData {
+#ifndef NDEBUG
+  u32 magic;    /* Magic number to detect structure corruption. */
+#endif
+  HANDLE hHeap; /* The handle to our heap. */
+  BOOL bOwned;  /* Do we own the heap (i.e. destroy it on shutdown)? */
+};
+
+#ifndef NDEBUG
+#define WINMEM_MAGIC     0x42b2830b
+#endif
+
+static struct winMemData win_mem_data = {
+#ifndef NDEBUG
+  WINMEM_MAGIC,
+#endif
+  NULL, FALSE
+};
+
+#ifndef NDEBUG
+#define winMemAssertMagic() assert( win_mem_data.magic==WINMEM_MAGIC )
+#else
+#define winMemAssertMagic()
+#endif
+
+#define winMemGetHeap() win_mem_data.hHeap
+
+static void *winMemMalloc(int nBytes);
+static void winMemFree(void *pPrior);
+static void *winMemRealloc(void *pPrior, int nBytes);
+static int winMemSize(void *p);
+static int winMemRoundup(int n);
+static int winMemInit(void *pAppData);
+static void winMemShutdown(void *pAppData);
+
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetWin32(void);
+#endif /* SQLITE_WIN32_MALLOC */
 
 /*
 ** The following variable is (normally) set once and never changes
-** thereafter.  It records whether the operating system is Win95
+** thereafter.  It records whether the operating system is Win9x
 ** or WinNT.
 **
 ** 0:   Operating system unknown.
-** 1:   Operating system is Win95.
+** 1:   Operating system is Win9x.
 ** 2:   Operating system is WinNT.
 **
 ** In order to facilitate testing on a WinNT system, the test fixture
@@ -27192,121 +30094,1072 @@ SQLITE_API int sqlite3_os_type = 0;
 static int sqlite3_os_type = 0;
 #endif
 
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+#  define SQLITE_WIN32_HAS_ANSI
+#endif
+
+#if SQLITE_OS_WINCE || SQLITE_OS_WINNT || SQLITE_OS_WINRT
+#  define SQLITE_WIN32_HAS_WIDE
+#endif
+
+#ifndef SYSCALL
+#  define SYSCALL sqlite3_syscall_ptr
+#endif
+
+/*
+** This function is not available on Windows CE or WinRT.
+ */
+
+#if SQLITE_OS_WINCE || SQLITE_OS_WINRT
+#  define osAreFileApisANSI()       1
+#endif
+
+/*
+** Many system calls are accessed through pointer-to-functions so that
+** they may be overridden at runtime to facilitate fault injection during
+** testing and sandboxing.  The following array holds the names and pointers
+** to all overrideable system calls.
+*/
+static struct win_syscall {
+  const char *zName;            /* Name of the sytem call */
+  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
+  sqlite3_syscall_ptr pDefault; /* Default value */
+} aSyscall[] = {
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "AreFileApisANSI",         (SYSCALL)AreFileApisANSI,         0 },
+#else
+  { "AreFileApisANSI",         (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osAreFileApisANSI
+#define osAreFileApisANSI ((BOOL(WINAPI*)(VOID))aSyscall[0].pCurrent)
+#endif
+
+#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CharLowerW",              (SYSCALL)CharLowerW,              0 },
+#else
+  { "CharLowerW",              (SYSCALL)0,                       0 },
+#endif
+
+#define osCharLowerW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[1].pCurrent)
+
+#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CharUpperW",              (SYSCALL)CharUpperW,              0 },
+#else
+  { "CharUpperW",              (SYSCALL)0,                       0 },
+#endif
+
+#define osCharUpperW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[2].pCurrent)
+
+  { "CloseHandle",             (SYSCALL)CloseHandle,             0 },
+
+#define osCloseHandle ((BOOL(WINAPI*)(HANDLE))aSyscall[3].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "CreateFileA",             (SYSCALL)CreateFileA,             0 },
+#else
+  { "CreateFileA",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileA ((HANDLE(WINAPI*)(LPCSTR,DWORD,DWORD, \
+        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[4].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CreateFileW",             (SYSCALL)CreateFileW,             0 },
+#else
+  { "CreateFileW",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
+        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)
+
+#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
+        !defined(SQLITE_OMIT_WAL))
+  { "CreateFileMappingW",      (SYSCALL)CreateFileMappingW,      0 },
+#else
+  { "CreateFileMappingW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
+        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[6].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CreateMutexW",            (SYSCALL)CreateMutexW,            0 },
+#else
+  { "CreateMutexW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateMutexW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,BOOL, \
+        LPCWSTR))aSyscall[7].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "DeleteFileA",             (SYSCALL)DeleteFileA,             0 },
+#else
+  { "DeleteFileA",             (SYSCALL)0,                       0 },
+#endif
+
+#define osDeleteFileA ((BOOL(WINAPI*)(LPCSTR))aSyscall[8].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "DeleteFileW",             (SYSCALL)DeleteFileW,             0 },
+#else
+  { "DeleteFileW",             (SYSCALL)0,                       0 },
+#endif
+
+#define osDeleteFileW ((BOOL(WINAPI*)(LPCWSTR))aSyscall[9].pCurrent)
+
+#if SQLITE_OS_WINCE
+  { "FileTimeToLocalFileTime", (SYSCALL)FileTimeToLocalFileTime, 0 },
+#else
+  { "FileTimeToLocalFileTime", (SYSCALL)0,                       0 },
+#endif
+
+#define osFileTimeToLocalFileTime ((BOOL(WINAPI*)(CONST FILETIME*, \
+        LPFILETIME))aSyscall[10].pCurrent)
+
+#if SQLITE_OS_WINCE
+  { "FileTimeToSystemTime",    (SYSCALL)FileTimeToSystemTime,    0 },
+#else
+  { "FileTimeToSystemTime",    (SYSCALL)0,                       0 },
+#endif
+
+#define osFileTimeToSystemTime ((BOOL(WINAPI*)(CONST FILETIME*, \
+        LPSYSTEMTIME))aSyscall[11].pCurrent)
+
+  { "FlushFileBuffers",        (SYSCALL)FlushFileBuffers,        0 },
+
+#define osFlushFileBuffers ((BOOL(WINAPI*)(HANDLE))aSyscall[12].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "FormatMessageA",          (SYSCALL)FormatMessageA,          0 },
+#else
+  { "FormatMessageA",          (SYSCALL)0,                       0 },
+#endif
+
+#define osFormatMessageA ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPSTR, \
+        DWORD,va_list*))aSyscall[13].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "FormatMessageW",          (SYSCALL)FormatMessageW,          0 },
+#else
+  { "FormatMessageW",          (SYSCALL)0,                       0 },
+#endif
+
+#define osFormatMessageW ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPWSTR, \
+        DWORD,va_list*))aSyscall[14].pCurrent)
+
+  { "FreeLibrary",             (SYSCALL)FreeLibrary,             0 },
+
+#define osFreeLibrary ((BOOL(WINAPI*)(HMODULE))aSyscall[15].pCurrent)
+
+  { "GetCurrentProcessId",     (SYSCALL)GetCurrentProcessId,     0 },
+
+#define osGetCurrentProcessId ((DWORD(WINAPI*)(VOID))aSyscall[16].pCurrent)
+
+#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetDiskFreeSpaceA",       (SYSCALL)GetDiskFreeSpaceA,       0 },
+#else
+  { "GetDiskFreeSpaceA",       (SYSCALL)0,                       0 },
+#endif
+
+#define osGetDiskFreeSpaceA ((BOOL(WINAPI*)(LPCSTR,LPDWORD,LPDWORD,LPDWORD, \
+        LPDWORD))aSyscall[17].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetDiskFreeSpaceW",       (SYSCALL)GetDiskFreeSpaceW,       0 },
+#else
+  { "GetDiskFreeSpaceW",       (SYSCALL)0,                       0 },
+#endif
+
+#define osGetDiskFreeSpaceW ((BOOL(WINAPI*)(LPCWSTR,LPDWORD,LPDWORD,LPDWORD, \
+        LPDWORD))aSyscall[18].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetFileAttributesA",      (SYSCALL)GetFileAttributesA,      0 },
+#else
+  { "GetFileAttributesA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesA ((DWORD(WINAPI*)(LPCSTR))aSyscall[19].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFileAttributesW",      (SYSCALL)GetFileAttributesW,      0 },
+#else
+  { "GetFileAttributesW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesW ((DWORD(WINAPI*)(LPCWSTR))aSyscall[20].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFileAttributesExW",    (SYSCALL)GetFileAttributesExW,    0 },
+#else
+  { "GetFileAttributesExW",    (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesExW ((BOOL(WINAPI*)(LPCWSTR,GET_FILEEX_INFO_LEVELS, \
+        LPVOID))aSyscall[21].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetFileSize",             (SYSCALL)GetFileSize,             0 },
+#else
+  { "GetFileSize",             (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileSize ((DWORD(WINAPI*)(HANDLE,LPDWORD))aSyscall[22].pCurrent)
+
+#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetFullPathNameA",        (SYSCALL)GetFullPathNameA,        0 },
+#else
+  { "GetFullPathNameA",        (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFullPathNameA ((DWORD(WINAPI*)(LPCSTR,DWORD,LPSTR, \
+        LPSTR*))aSyscall[23].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFullPathNameW",        (SYSCALL)GetFullPathNameW,        0 },
+#else
+  { "GetFullPathNameW",        (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFullPathNameW ((DWORD(WINAPI*)(LPCWSTR,DWORD,LPWSTR, \
+        LPWSTR*))aSyscall[24].pCurrent)
+
+  { "GetLastError",            (SYSCALL)GetLastError,            0 },
+
+#define osGetLastError ((DWORD(WINAPI*)(VOID))aSyscall[25].pCurrent)
+
+#if SQLITE_OS_WINCE
+  /* The GetProcAddressA() routine is only available on Windows CE. */
+  { "GetProcAddressA",         (SYSCALL)GetProcAddressA,         0 },
+#else
+  /* All other Windows platforms expect GetProcAddress() to take
+  ** an ANSI string regardless of the _UNICODE setting */
+  { "GetProcAddressA",         (SYSCALL)GetProcAddress,          0 },
+#endif
+
+#define osGetProcAddressA ((FARPROC(WINAPI*)(HMODULE, \
+        LPCSTR))aSyscall[26].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetSystemInfo",           (SYSCALL)GetSystemInfo,           0 },
+#else
+  { "GetSystemInfo",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetSystemInfo ((VOID(WINAPI*)(LPSYSTEM_INFO))aSyscall[27].pCurrent)
+
+  { "GetSystemTime",           (SYSCALL)GetSystemTime,           0 },
+
+#define osGetSystemTime ((VOID(WINAPI*)(LPSYSTEMTIME))aSyscall[28].pCurrent)
+
+#if !SQLITE_OS_WINCE
+  { "GetSystemTimeAsFileTime", (SYSCALL)GetSystemTimeAsFileTime, 0 },
+#else
+  { "GetSystemTimeAsFileTime", (SYSCALL)0,                       0 },
+#endif
+
+#define osGetSystemTimeAsFileTime ((VOID(WINAPI*)( \
+        LPFILETIME))aSyscall[29].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetTempPathA",            (SYSCALL)GetTempPathA,            0 },
+#else
+  { "GetTempPathA",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTempPathA ((DWORD(WINAPI*)(DWORD,LPSTR))aSyscall[30].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetTempPathW",            (SYSCALL)GetTempPathW,            0 },
+#else
+  { "GetTempPathW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTempPathW ((DWORD(WINAPI*)(DWORD,LPWSTR))aSyscall[31].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetTickCount",            (SYSCALL)GetTickCount,            0 },
+#else
+  { "GetTickCount",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTickCount ((DWORD(WINAPI*)(VOID))aSyscall[32].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetVersionExA",           (SYSCALL)GetVersionExA,           0 },
+#else
+  { "GetVersionExA",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetVersionExA ((BOOL(WINAPI*)( \
+        LPOSVERSIONINFOA))aSyscall[33].pCurrent)
+
+  { "HeapAlloc",               (SYSCALL)HeapAlloc,               0 },
+
+#define osHeapAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD, \
+        SIZE_T))aSyscall[34].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapCreate",              (SYSCALL)HeapCreate,              0 },
+#else
+  { "HeapCreate",              (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapCreate ((HANDLE(WINAPI*)(DWORD,SIZE_T, \
+        SIZE_T))aSyscall[35].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapDestroy",             (SYSCALL)HeapDestroy,             0 },
+#else
+  { "HeapDestroy",             (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapDestroy ((BOOL(WINAPI*)(HANDLE))aSyscall[36].pCurrent)
+
+  { "HeapFree",                (SYSCALL)HeapFree,                0 },
+
+#define osHeapFree ((BOOL(WINAPI*)(HANDLE,DWORD,LPVOID))aSyscall[37].pCurrent)
+
+  { "HeapReAlloc",             (SYSCALL)HeapReAlloc,             0 },
+
+#define osHeapReAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD,LPVOID, \
+        SIZE_T))aSyscall[38].pCurrent)
+
+  { "HeapSize",                (SYSCALL)HeapSize,                0 },
+
+#define osHeapSize ((SIZE_T(WINAPI*)(HANDLE,DWORD, \
+        LPCVOID))aSyscall[39].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapValidate",            (SYSCALL)HeapValidate,            0 },
+#else
+  { "HeapValidate",            (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapValidate ((BOOL(WINAPI*)(HANDLE,DWORD, \
+        LPCVOID))aSyscall[40].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "LoadLibraryA",            (SYSCALL)LoadLibraryA,            0 },
+#else
+  { "LoadLibraryA",            (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadLibraryA ((HMODULE(WINAPI*)(LPCSTR))aSyscall[41].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "LoadLibraryW",            (SYSCALL)LoadLibraryW,            0 },
+#else
+  { "LoadLibraryW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadLibraryW ((HMODULE(WINAPI*)(LPCWSTR))aSyscall[42].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "LocalFree",               (SYSCALL)LocalFree,               0 },
+#else
+  { "LocalFree",               (SYSCALL)0,                       0 },
+#endif
+
+#define osLocalFree ((HLOCAL(WINAPI*)(HLOCAL))aSyscall[43].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "LockFile",                (SYSCALL)LockFile,                0 },
+#else
+  { "LockFile",                (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osLockFile
+#define osLockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        DWORD))aSyscall[44].pCurrent)
+#endif
+
+#if !SQLITE_OS_WINCE
+  { "LockFileEx",              (SYSCALL)LockFileEx,              0 },
+#else
+  { "LockFileEx",              (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osLockFileEx
+#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
+        LPOVERLAPPED))aSyscall[45].pCurrent)
+#endif
+
+#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && !defined(SQLITE_OMIT_WAL))
+  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },
+#else
+  { "MapViewOfFile",           (SYSCALL)0,                       0 },
+#endif
+
+#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        SIZE_T))aSyscall[46].pCurrent)
+
+  { "MultiByteToWideChar",     (SYSCALL)MultiByteToWideChar,     0 },
+
+#define osMultiByteToWideChar ((int(WINAPI*)(UINT,DWORD,LPCSTR,int,LPWSTR, \
+        int))aSyscall[47].pCurrent)
+
+  { "QueryPerformanceCounter", (SYSCALL)QueryPerformanceCounter, 0 },
+
+#define osQueryPerformanceCounter ((BOOL(WINAPI*)( \
+        LARGE_INTEGER*))aSyscall[48].pCurrent)
+
+  { "ReadFile",                (SYSCALL)ReadFile,                0 },
+
+#define osReadFile ((BOOL(WINAPI*)(HANDLE,LPVOID,DWORD,LPDWORD, \
+        LPOVERLAPPED))aSyscall[49].pCurrent)
+
+  { "SetEndOfFile",            (SYSCALL)SetEndOfFile,            0 },
+
+#define osSetEndOfFile ((BOOL(WINAPI*)(HANDLE))aSyscall[50].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "SetFilePointer",          (SYSCALL)SetFilePointer,          0 },
+#else
+  { "SetFilePointer",          (SYSCALL)0,                       0 },
+#endif
+
+#define osSetFilePointer ((DWORD(WINAPI*)(HANDLE,LONG,PLONG, \
+        DWORD))aSyscall[51].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "Sleep",                   (SYSCALL)Sleep,                   0 },
+#else
+  { "Sleep",                   (SYSCALL)0,                       0 },
+#endif
+
+#define osSleep ((VOID(WINAPI*)(DWORD))aSyscall[52].pCurrent)
+
+  { "SystemTimeToFileTime",    (SYSCALL)SystemTimeToFileTime,    0 },
+
+#define osSystemTimeToFileTime ((BOOL(WINAPI*)(CONST SYSTEMTIME*, \
+        LPFILETIME))aSyscall[53].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "UnlockFile",              (SYSCALL)UnlockFile,              0 },
+#else
+  { "UnlockFile",              (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osUnlockFile
+#define osUnlockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        DWORD))aSyscall[54].pCurrent)
+#endif
+
+#if !SQLITE_OS_WINCE
+  { "UnlockFileEx",            (SYSCALL)UnlockFileEx,            0 },
+#else
+  { "UnlockFileEx",            (SYSCALL)0,                       0 },
+#endif
+
+#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        LPOVERLAPPED))aSyscall[55].pCurrent)
+
+#if SQLITE_OS_WINCE || !defined(SQLITE_OMIT_WAL)
+  { "UnmapViewOfFile",         (SYSCALL)UnmapViewOfFile,         0 },
+#else
+  { "UnmapViewOfFile",         (SYSCALL)0,                       0 },
+#endif
+
+#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[56].pCurrent)
+
+  { "WideCharToMultiByte",     (SYSCALL)WideCharToMultiByte,     0 },
+
+#define osWideCharToMultiByte ((int(WINAPI*)(UINT,DWORD,LPCWSTR,int,LPSTR,int, \
+        LPCSTR,LPBOOL))aSyscall[57].pCurrent)
+
+  { "WriteFile",               (SYSCALL)WriteFile,               0 },
+
+#define osWriteFile ((BOOL(WINAPI*)(HANDLE,LPCVOID,DWORD,LPDWORD, \
+        LPOVERLAPPED))aSyscall[58].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "CreateEventExW",          (SYSCALL)CreateEventExW,          0 },
+#else
+  { "CreateEventExW",          (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateEventExW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,LPCWSTR, \
+        DWORD,DWORD))aSyscall[59].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "WaitForSingleObject",     (SYSCALL)WaitForSingleObject,     0 },
+#else
+  { "WaitForSingleObject",     (SYSCALL)0,                       0 },
+#endif
+
+#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
+        DWORD))aSyscall[60].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
+#else
+  { "WaitForSingleObjectEx",   (SYSCALL)0,                       0 },
+#endif
+
+#define osWaitForSingleObjectEx ((DWORD(WINAPI*)(HANDLE,DWORD, \
+        BOOL))aSyscall[61].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "SetFilePointerEx",        (SYSCALL)SetFilePointerEx,        0 },
+#else
+  { "SetFilePointerEx",        (SYSCALL)0,                       0 },
+#endif
+
+#define osSetFilePointerEx ((BOOL(WINAPI*)(HANDLE,LARGE_INTEGER, \
+        PLARGE_INTEGER,DWORD))aSyscall[62].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetFileInformationByHandleEx", (SYSCALL)GetFileInformationByHandleEx, 0 },
+#else
+  { "GetFileInformationByHandleEx", (SYSCALL)0,                  0 },
+#endif
+
+#define osGetFileInformationByHandleEx ((BOOL(WINAPI*)(HANDLE, \
+        FILE_INFO_BY_HANDLE_CLASS,LPVOID,DWORD))aSyscall[63].pCurrent)
+
+#if SQLITE_OS_WINRT && !defined(SQLITE_OMIT_WAL)
+  { "MapViewOfFileFromApp",    (SYSCALL)MapViewOfFileFromApp,    0 },
+#else
+  { "MapViewOfFileFromApp",    (SYSCALL)0,                       0 },
+#endif
+
+#define osMapViewOfFileFromApp ((LPVOID(WINAPI*)(HANDLE,ULONG,ULONG64, \
+        SIZE_T))aSyscall[64].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "CreateFile2",             (SYSCALL)CreateFile2,             0 },
+#else
+  { "CreateFile2",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFile2 ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD,DWORD, \
+        LPCREATEFILE2_EXTENDED_PARAMETERS))aSyscall[65].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "LoadPackagedLibrary",     (SYSCALL)LoadPackagedLibrary,     0 },
+#else
+  { "LoadPackagedLibrary",     (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadPackagedLibrary ((HMODULE(WINAPI*)(LPCWSTR, \
+        DWORD))aSyscall[66].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetTickCount64",          (SYSCALL)GetTickCount64,          0 },
+#else
+  { "GetTickCount64",          (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTickCount64 ((ULONGLONG(WINAPI*)(VOID))aSyscall[67].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetNativeSystemInfo",     (SYSCALL)GetNativeSystemInfo,     0 },
+#else
+  { "GetNativeSystemInfo",     (SYSCALL)0,                       0 },
+#endif
+
+#define osGetNativeSystemInfo ((VOID(WINAPI*)( \
+        LPSYSTEM_INFO))aSyscall[68].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "OutputDebugStringA",      (SYSCALL)OutputDebugStringA,      0 },
+#else
+  { "OutputDebugStringA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osOutputDebugStringA ((VOID(WINAPI*)(LPCSTR))aSyscall[69].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "OutputDebugStringW",      (SYSCALL)OutputDebugStringW,      0 },
+#else
+  { "OutputDebugStringW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osOutputDebugStringW ((VOID(WINAPI*)(LPCWSTR))aSyscall[70].pCurrent)
+
+  { "GetProcessHeap",          (SYSCALL)GetProcessHeap,          0 },
+
+#define osGetProcessHeap ((HANDLE(WINAPI*)(VOID))aSyscall[71].pCurrent)
+
+#if SQLITE_OS_WINRT && !defined(SQLITE_OMIT_WAL)
+  { "CreateFileMappingFromApp", (SYSCALL)CreateFileMappingFromApp, 0 },
+#else
+  { "CreateFileMappingFromApp", (SYSCALL)0,                      0 },
+#endif
+
+#define osCreateFileMappingFromApp ((HANDLE(WINAPI*)(HANDLE, \
+        LPSECURITY_ATTRIBUTES,ULONG,ULONG64,LPCWSTR))aSyscall[72].pCurrent)
+
+}; /* End of the overrideable system calls */
+
+/*
+** This is the xSetSystemCall() method of sqlite3_vfs for all of the
+** "win32" VFSes.  Return SQLITE_OK opon successfully updating the
+** system call pointer, or SQLITE_NOTFOUND if there is no configurable
+** system call named zName.
+*/
+static int winSetSystemCall(
+  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
+  const char *zName,            /* Name of system call to override */
+  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
+){
+  unsigned int i;
+  int rc = SQLITE_NOTFOUND;
+
+  UNUSED_PARAMETER(pNotUsed);
+  if( zName==0 ){
+    /* If no zName is given, restore all system calls to their default
+    ** settings and return NULL
+    */
+    rc = SQLITE_OK;
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( aSyscall[i].pDefault ){
+        aSyscall[i].pCurrent = aSyscall[i].pDefault;
+      }
+    }
+  }else{
+    /* If zName is specified, operate on only the one system call
+    ** specified.
+    */
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ){
+        if( aSyscall[i].pDefault==0 ){
+          aSyscall[i].pDefault = aSyscall[i].pCurrent;
+        }
+        rc = SQLITE_OK;
+        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
+        aSyscall[i].pCurrent = pNewFunc;
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the value of a system call.  Return NULL if zName is not a
+** recognized system call name.  NULL is also returned if the system call
+** is currently undefined.
+*/
+static sqlite3_syscall_ptr winGetSystemCall(
+  sqlite3_vfs *pNotUsed,
+  const char *zName
+){
+  unsigned int i;
+
+  UNUSED_PARAMETER(pNotUsed);
+  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
+  }
+  return 0;
+}
+
+/*
+** Return the name of the first system call after zName.  If zName==NULL
+** then return the name of the first system call.  Return NULL if zName
+** is the last system call or if zName is not the name of a valid
+** system call.
+*/
+static const char *winNextSystemCall(sqlite3_vfs *p, const char *zName){
+  int i = -1;
+
+  UNUSED_PARAMETER(p);
+  if( zName ){
+    for(i=0; i<ArraySize(aSyscall)-1; i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
+    }
+  }
+  for(i++; i<ArraySize(aSyscall); i++){
+    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
+  }
+  return 0;
+}
+
+/*
+** This function outputs the specified (ANSI) string to the Win32 debugger
+** (if available).
+*/
+
+SQLITE_API void sqlite3_win32_write_debug(char *zBuf, int nBuf){
+  char zDbgBuf[SQLITE_WIN32_DBG_BUF_SIZE];
+  int nMin = MIN(nBuf, (SQLITE_WIN32_DBG_BUF_SIZE - 1)); /* may be negative. */
+  if( nMin<-1 ) nMin = -1; /* all negative values become -1. */
+  assert( nMin==-1 || nMin==0 || nMin<SQLITE_WIN32_DBG_BUF_SIZE );
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  if( nMin>0 ){
+    memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+    memcpy(zDbgBuf, zBuf, nMin);
+    osOutputDebugStringA(zDbgBuf);
+  }else{
+    osOutputDebugStringA(zBuf);
+  }
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+  memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+  if ( osMultiByteToWideChar(
+          osAreFileApisANSI() ? CP_ACP : CP_OEMCP, 0, zBuf,
+          nMin, (LPWSTR)zDbgBuf, SQLITE_WIN32_DBG_BUF_SIZE/sizeof(WCHAR))<=0 ){
+    return;
+  }
+  osOutputDebugStringW((LPCWSTR)zDbgBuf);
+#else
+  if( nMin>0 ){
+    memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+    memcpy(zDbgBuf, zBuf, nMin);
+    fprintf(stderr, "%s", zDbgBuf);
+  }else{
+    fprintf(stderr, "%s", zBuf);
+  }
+#endif
+}
+
+/*
+** The following routine suspends the current thread for at least ms
+** milliseconds.  This is equivalent to the Win32 Sleep() interface.
+*/
+#if SQLITE_OS_WINRT
+static HANDLE sleepObj = NULL;
+#endif
+
+SQLITE_API void sqlite3_win32_sleep(DWORD milliseconds){
+#if SQLITE_OS_WINRT
+  if ( sleepObj==NULL ){
+    sleepObj = osCreateEventExW(NULL, NULL, CREATE_EVENT_MANUAL_RESET,
+                                SYNCHRONIZE);
+  }
+  assert( sleepObj!=NULL );
+  osWaitForSingleObjectEx(sleepObj, milliseconds, FALSE);
+#else
+  osSleep(milliseconds);
+#endif
+}
+
 /*
 ** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
 ** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
 **
 ** Here is an interesting observation:  Win95, Win98, and WinME lack
 ** the LockFileEx() API.  But we can still statically link against that
-** API as long as we don't call it win running Win95/98/ME.  A call to
+** API as long as we don't call it when running Win95/98/ME.  A call to
 ** this routine is used to determine if the host is Win95/98/ME or
 ** WinNT/2K/XP so that we will know whether or not we can safely call
 ** the LockFileEx() API.
 */
-#if SQLITE_OS_WINCE
+#if SQLITE_OS_WINCE || SQLITE_OS_WINRT
 # define isNT()  (1)
 #else
   static int isNT(void){
     if( sqlite3_os_type==0 ){
-      OSVERSIONINFO sInfo;
+      OSVERSIONINFOA sInfo;
       sInfo.dwOSVersionInfoSize = sizeof(sInfo);
-      GetVersionEx(&sInfo);
+      osGetVersionExA(&sInfo);
       sqlite3_os_type = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1;
     }
     return sqlite3_os_type==2;
   }
 #endif /* SQLITE_OS_WINCE */
 
+#ifdef SQLITE_WIN32_MALLOC
 /*
-** Convert a UTF-8 string to microsoft unicode (UTF-16?). 
+** Allocate nBytes of memory.
+*/
+static void *winMemMalloc(int nBytes){
+  HANDLE hHeap;
+  void *p;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+  assert( nBytes>=0 );
+  p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
+  if( !p ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapAlloc %u bytes (%d), heap=%p",
+                nBytes, osGetLastError(), (void*)hHeap);
+  }
+  return p;
+}
+
+/*
+** Free memory.
+*/
+static void winMemFree(void *pPrior){
+  HANDLE hHeap;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
+#endif
+  if( !pPrior ) return; /* Passing NULL to HeapFree is undefined. */
+  if( !osHeapFree(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapFree block %p (%d), heap=%p",
+                pPrior, osGetLastError(), (void*)hHeap);
+  }
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+static void *winMemRealloc(void *pPrior, int nBytes){
+  HANDLE hHeap;
+  void *p;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
+#endif
+  assert( nBytes>=0 );
+  if( !pPrior ){
+    p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
+  }else{
+    p = osHeapReAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior, (SIZE_T)nBytes);
+  }
+  if( !p ){
+    sqlite3_log(SQLITE_NOMEM, "failed to %s %u bytes (%d), heap=%p",
+                pPrior ? "HeapReAlloc" : "HeapAlloc", nBytes, osGetLastError(),
+                (void*)hHeap);
+  }
+  return p;
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.
+*/
+static int winMemSize(void *p){
+  HANDLE hHeap;
+  SIZE_T n;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+  if( !p ) return 0;
+  n = osHeapSize(hHeap, SQLITE_WIN32_HEAP_FLAGS, p);
+  if( n==(SIZE_T)-1 ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapSize block %p (%d), heap=%p",
+                p, osGetLastError(), (void*)hHeap);
+    return 0;
+  }
+  return (int)n;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int winMemRoundup(int n){
+  return n;
+}
+
+/*
+** Initialize this module.
+*/
+static int winMemInit(void *pAppData){
+  winMemData *pWinMemData = (winMemData *)pAppData;
+
+  if( !pWinMemData ) return SQLITE_ERROR;
+  assert( pWinMemData->magic==WINMEM_MAGIC );
+
+#if !SQLITE_OS_WINRT && SQLITE_WIN32_HEAP_CREATE
+  if( !pWinMemData->hHeap ){
+    pWinMemData->hHeap = osHeapCreate(SQLITE_WIN32_HEAP_FLAGS,
+                                      SQLITE_WIN32_HEAP_INIT_SIZE,
+                                      SQLITE_WIN32_HEAP_MAX_SIZE);
+    if( !pWinMemData->hHeap ){
+      sqlite3_log(SQLITE_NOMEM,
+          "failed to HeapCreate (%d), flags=%u, initSize=%u, maxSize=%u",
+          osGetLastError(), SQLITE_WIN32_HEAP_FLAGS,
+          SQLITE_WIN32_HEAP_INIT_SIZE, SQLITE_WIN32_HEAP_MAX_SIZE);
+      return SQLITE_NOMEM;
+    }
+    pWinMemData->bOwned = TRUE;
+    assert( pWinMemData->bOwned );
+  }
+#else
+  pWinMemData->hHeap = osGetProcessHeap();
+  if( !pWinMemData->hHeap ){
+    sqlite3_log(SQLITE_NOMEM,
+        "failed to GetProcessHeap (%d)", osGetLastError());
+    return SQLITE_NOMEM;
+  }
+  pWinMemData->bOwned = FALSE;
+  assert( !pWinMemData->bOwned );
+#endif
+  assert( pWinMemData->hHeap!=0 );
+  assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void winMemShutdown(void *pAppData){
+  winMemData *pWinMemData = (winMemData *)pAppData;
+
+  if( !pWinMemData ) return;
+  if( pWinMemData->hHeap ){
+    assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+    assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+    if( pWinMemData->bOwned ){
+      if( !osHeapDestroy(pWinMemData->hHeap) ){
+        sqlite3_log(SQLITE_NOMEM, "failed to HeapDestroy (%d), heap=%p",
+                    osGetLastError(), (void*)pWinMemData->hHeap);
+      }
+      pWinMemData->bOwned = FALSE;
+    }
+    pWinMemData->hHeap = NULL;
+  }
+}
+
+/*
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file. The
+** arguments specify the block of memory to manage.
+**
+** This routine is only called by sqlite3_config(), and therefore
+** is not required to be threadsafe (it is not).
+*/
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetWin32(void){
+  static const sqlite3_mem_methods winMemMethods = {
+    winMemMalloc,
+    winMemFree,
+    winMemRealloc,
+    winMemSize,
+    winMemRoundup,
+    winMemInit,
+    winMemShutdown,
+    &win_mem_data
+  };
+  return &winMemMethods;
+}
+
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  sqlite3_config(SQLITE_CONFIG_MALLOC, sqlite3MemGetWin32());
+}
+#endif /* SQLITE_WIN32_MALLOC */
+
+/*
+** Convert a UTF-8 string to Microsoft Unicode (UTF-16?). 
 **
 ** Space to hold the returned string is obtained from malloc.
 */
-static WCHAR *utf8ToUnicode(const char *zFilename){
+static LPWSTR utf8ToUnicode(const char *zFilename){
   int nChar;
-  WCHAR *zWideFilename;
+  LPWSTR zWideFilename;
 
-  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
-  zWideFilename = malloc( nChar*sizeof(zWideFilename[0]) );
+  nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
+  if( nChar==0 ){
+    return 0;
+  }
+  zWideFilename = sqlite3_malloc( nChar*sizeof(zWideFilename[0]) );
   if( zWideFilename==0 ){
     return 0;
   }
-  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename, nChar);
+  nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename,
+                                nChar);
   if( nChar==0 ){
-    free(zWideFilename);
+    sqlite3_free(zWideFilename);
     zWideFilename = 0;
   }
   return zWideFilename;
 }
 
 /*
-** Convert microsoft unicode to UTF-8.  Space to hold the returned string is
-** obtained from malloc().
+** Convert Microsoft Unicode to UTF-8.  Space to hold the returned string is
+** obtained from sqlite3_malloc().
 */
-static char *unicodeToUtf8(const WCHAR *zWideFilename){
+static char *unicodeToUtf8(LPCWSTR zWideFilename){
   int nByte;
   char *zFilename;
 
-  nByte = WideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, 0, 0, 0, 0);
-  zFilename = malloc( nByte );
+  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, 0, 0, 0, 0);
+  if( nByte == 0 ){
+    return 0;
+  }
+  zFilename = sqlite3_malloc( nByte );
   if( zFilename==0 ){
     return 0;
   }
-  nByte = WideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, zFilename, nByte,
-                              0, 0);
+  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, zFilename, nByte,
+                                0, 0);
   if( nByte == 0 ){
-    free(zFilename);
+    sqlite3_free(zFilename);
     zFilename = 0;
   }
   return zFilename;
 }
 
 /*
-** Convert an ansi string to microsoft unicode, based on the
+** Convert an ANSI string to Microsoft Unicode, based on the
 ** current codepage settings for file apis.
 ** 
 ** Space to hold the returned string is obtained
-** from malloc.
+** from sqlite3_malloc.
 */
-static WCHAR *mbcsToUnicode(const char *zFilename){
+static LPWSTR mbcsToUnicode(const char *zFilename){
   int nByte;
-  WCHAR *zMbcsFilename;
-  int codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+  LPWSTR zMbcsFilename;
+  int codepage = osAreFileApisANSI() ? CP_ACP : CP_OEMCP;
 
-  nByte = MultiByteToWideChar(codepage, 0, zFilename, -1, NULL,0)*sizeof(WCHAR);
-  zMbcsFilename = malloc( nByte*sizeof(zMbcsFilename[0]) );
+  nByte = osMultiByteToWideChar(codepage, 0, zFilename, -1, NULL,
+                                0)*sizeof(WCHAR);
+  if( nByte==0 ){
+    return 0;
+  }
+  zMbcsFilename = sqlite3_malloc( nByte*sizeof(zMbcsFilename[0]) );
   if( zMbcsFilename==0 ){
     return 0;
   }
-  nByte = MultiByteToWideChar(codepage, 0, zFilename, -1, zMbcsFilename, nByte);
+  nByte = osMultiByteToWideChar(codepage, 0, zFilename, -1, zMbcsFilename,
+                                nByte);
   if( nByte==0 ){
-    free(zMbcsFilename);
+    sqlite3_free(zMbcsFilename);
     zMbcsFilename = 0;
   }
   return zMbcsFilename;
 }
 
 /*
-** Convert microsoft unicode to multibyte character string, based on the
-** user's Ansi codepage.
+** Convert Microsoft Unicode to multi-byte character string, based on the
+** user's ANSI codepage.
 **
 ** Space to hold the returned string is obtained from
-** malloc().
+** sqlite3_malloc().
 */
-static char *unicodeToMbcs(const WCHAR *zWideFilename){
+static char *unicodeToMbcs(LPCWSTR zWideFilename){
   int nByte;
   char *zFilename;
-  int codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+  int codepage = osAreFileApisANSI() ? CP_ACP : CP_OEMCP;
 
-  nByte = WideCharToMultiByte(codepage, 0, zWideFilename, -1, 0, 0, 0, 0);
-  zFilename = malloc( nByte );
+  nByte = osWideCharToMultiByte(codepage, 0, zWideFilename, -1, 0, 0, 0, 0);
+  if( nByte == 0 ){
+    return 0;
+  }
+  zFilename = sqlite3_malloc( nByte );
   if( zFilename==0 ){
     return 0;
   }
-  nByte = WideCharToMultiByte(codepage, 0, zWideFilename, -1, zFilename, nByte,
-                              0, 0);
+  nByte = osWideCharToMultiByte(codepage, 0, zWideFilename, -1, zFilename,
+                                nByte, 0, 0);
   if( nByte == 0 ){
-    free(zFilename);
+    sqlite3_free(zFilename);
     zFilename = 0;
   }
   return zFilename;
@@ -27314,46 +31167,257 @@ static char *unicodeToMbcs(const WCHAR *zWideFilename){
 
 /*
 ** Convert multibyte character string to UTF-8.  Space to hold the
-** returned string is obtained from malloc().
+** returned string is obtained from sqlite3_malloc().
 */
 SQLITE_API char *sqlite3_win32_mbcs_to_utf8(const char *zFilename){
   char *zFilenameUtf8;
-  WCHAR *zTmpWide;
+  LPWSTR zTmpWide;
 
   zTmpWide = mbcsToUnicode(zFilename);
   if( zTmpWide==0 ){
     return 0;
   }
   zFilenameUtf8 = unicodeToUtf8(zTmpWide);
-  free(zTmpWide);
+  sqlite3_free(zTmpWide);
   return zFilenameUtf8;
 }
 
 /*
 ** Convert UTF-8 to multibyte character string.  Space to hold the 
-** returned string is obtained from malloc().
+** returned string is obtained from sqlite3_malloc().
 */
-static char *utf8ToMbcs(const char *zFilename){
+SQLITE_API char *sqlite3_win32_utf8_to_mbcs(const char *zFilename){
   char *zFilenameMbcs;
-  WCHAR *zTmpWide;
+  LPWSTR zTmpWide;
 
   zTmpWide = utf8ToUnicode(zFilename);
   if( zTmpWide==0 ){
     return 0;
   }
   zFilenameMbcs = unicodeToMbcs(zTmpWide);
-  free(zTmpWide);
+  sqlite3_free(zTmpWide);
   return zFilenameMbcs;
 }
 
+/*
+** This function sets the data directory or the temporary directory based on
+** the provided arguments.  The type argument must be 1 in order to set the
+** data directory or 2 in order to set the temporary directory.  The zValue
+** argument is the name of the directory to use.  The return value will be
+** SQLITE_OK if successful.
+*/
+SQLITE_API int sqlite3_win32_set_directory(DWORD type, LPCWSTR zValue){
+  char **ppDirectory = 0;
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  if( type==SQLITE_WIN32_DATA_DIRECTORY_TYPE ){
+    ppDirectory = &sqlite3_data_directory;
+  }else if( type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE ){
+    ppDirectory = &sqlite3_temp_directory;
+  }
+  assert( !ppDirectory || type==SQLITE_WIN32_DATA_DIRECTORY_TYPE
+          || type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE
+  );
+  assert( !ppDirectory || sqlite3MemdebugHasType(*ppDirectory, MEMTYPE_HEAP) );
+  if( ppDirectory ){
+    char *zValueUtf8 = 0;
+    if( zValue && zValue[0] ){
+      zValueUtf8 = unicodeToUtf8(zValue);
+      if ( zValueUtf8==0 ){
+        return SQLITE_NOMEM;
+      }
+    }
+    sqlite3_free(*ppDirectory);
+    *ppDirectory = zValueUtf8;
+    return SQLITE_OK;
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** The return value of getLastErrorMsg
+** is zero if the error message fits in the buffer, or non-zero
+** otherwise (if the message was truncated).
+*/
+static int getLastErrorMsg(DWORD lastErrno, int nBuf, char *zBuf){
+  /* FormatMessage returns 0 on failure.  Otherwise it
+  ** returns the number of TCHARs written to the output
+  ** buffer, excluding the terminating null char.
+  */
+  DWORD dwLen = 0;
+  char *zOut = 0;
+
+  if( isNT() ){
+#if SQLITE_OS_WINRT
+    WCHAR zTempWide[MAX_PATH+1]; /* NOTE: Somewhat arbitrary. */
+    dwLen = osFormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             zTempWide,
+                             MAX_PATH,
+                             0);
+#else
+    LPWSTR zTempWide = NULL;
+    dwLen = osFormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                             FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             (LPWSTR) &zTempWide,
+                             0,
+                             0);
+#endif
+    if( dwLen > 0 ){
+      /* allocate a buffer and convert to UTF8 */
+      sqlite3BeginBenignMalloc();
+      zOut = unicodeToUtf8(zTempWide);
+      sqlite3EndBenignMalloc();
+#if !SQLITE_OS_WINRT
+      /* free the system buffer allocated by FormatMessage */
+      osLocalFree(zTempWide);
+#endif
+    }
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zTemp = NULL;
+    dwLen = osFormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                             FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             (LPSTR) &zTemp,
+                             0,
+                             0);
+    if( dwLen > 0 ){
+      /* allocate a buffer and convert to UTF8 */
+      sqlite3BeginBenignMalloc();
+      zOut = sqlite3_win32_mbcs_to_utf8(zTemp);
+      sqlite3EndBenignMalloc();
+      /* free the system buffer allocated by FormatMessage */
+      osLocalFree(zTemp);
+    }
+  }
+#endif
+  if( 0 == dwLen ){
+    sqlite3_snprintf(nBuf, zBuf, "OsError 0x%x (%u)", lastErrno, lastErrno);
+  }else{
+    /* copy a maximum of nBuf chars to output buffer */
+    sqlite3_snprintf(nBuf, zBuf, "%s", zOut);
+    /* free the UTF8 buffer */
+    sqlite3_free(zOut);
+  }
+  return 0;
+}
+
+/*
+**
+** This function - winLogErrorAtLine() - is only ever called via the macro
+** winLogError().
+**
+** This routine is invoked after an error occurs in an OS function.
+** It logs a message using sqlite3_log() containing the current value of
+** error code and, if possible, the human-readable equivalent from 
+** FormatMessage.
+**
+** The first argument passed to the macro should be the error code that
+** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). 
+** The two subsequent arguments should be the name of the OS function that
+** failed and the associated file-system path, if any.
+*/
+#define winLogError(a,b,c,d)   winLogErrorAtLine(a,b,c,d,__LINE__)
+static int winLogErrorAtLine(
+  int errcode,                    /* SQLite error code */
+  DWORD lastErrno,                /* Win32 last error */
+  const char *zFunc,              /* Name of OS function that failed */
+  const char *zPath,              /* File path associated with error */
+  int iLine                       /* Source line number where error occurred */
+){
+  char zMsg[500];                 /* Human readable error text */
+  int i;                          /* Loop counter */
+
+  zMsg[0] = 0;
+  getLastErrorMsg(lastErrno, sizeof(zMsg), zMsg);
+  assert( errcode!=SQLITE_OK );
+  if( zPath==0 ) zPath = "";
+  for(i=0; zMsg[i] && zMsg[i]!='\r' && zMsg[i]!='\n'; i++){}
+  zMsg[i] = 0;
+  sqlite3_log(errcode,
+      "os_win.c:%d: (%d) %s(%s) - %s",
+      iLine, lastErrno, zFunc, zPath, zMsg
+  );
+
+  return errcode;
+}
+
+/*
+** The number of times that a ReadFile(), WriteFile(), and DeleteFile()
+** will be retried following a locking error - probably caused by 
+** antivirus software.  Also the initial delay before the first retry.
+** The delay increases linearly with each retry.
+*/
+#ifndef SQLITE_WIN32_IOERR_RETRY
+# define SQLITE_WIN32_IOERR_RETRY 10
+#endif
+#ifndef SQLITE_WIN32_IOERR_RETRY_DELAY
+# define SQLITE_WIN32_IOERR_RETRY_DELAY 25
+#endif
+static int win32IoerrRetry = SQLITE_WIN32_IOERR_RETRY;
+static int win32IoerrRetryDelay = SQLITE_WIN32_IOERR_RETRY_DELAY;
+
+/*
+** If a ReadFile() or WriteFile() error occurs, invoke this routine
+** to see if it should be retried.  Return TRUE to retry.  Return FALSE
+** to give up with an error.
+*/
+static int retryIoerr(int *pnRetry, DWORD *pError){
+  DWORD e = osGetLastError();
+  if( *pnRetry>=win32IoerrRetry ){
+    if( pError ){
+      *pError = e;
+    }
+    return 0;
+  }
+  if( e==ERROR_ACCESS_DENIED ||
+      e==ERROR_LOCK_VIOLATION ||
+      e==ERROR_SHARING_VIOLATION ){
+    sqlite3_win32_sleep(win32IoerrRetryDelay*(1+*pnRetry));
+    ++*pnRetry;
+    return 1;
+  }
+  if( pError ){
+    *pError = e;
+  }
+  return 0;
+}
+
+/*
+** Log a I/O error retry episode.
+*/
+static void logIoerr(int nRetry){
+  if( nRetry ){
+    sqlite3_log(SQLITE_IOERR, 
+      "delayed %dms for lock/sharing conflict",
+      win32IoerrRetryDelay*nRetry*(nRetry+1)/2
+    );
+  }
+}
+
 #if SQLITE_OS_WINCE
 /*************************************************************************
 ** This section contains code for WinCE only.
 */
 /*
-** WindowsCE does not have a localtime() function.  So create a
+** Windows CE does not have a localtime() function.  So create a
 ** substitute.
 */
+/* #include <time.h> */
 struct tm *__cdecl localtime(const time_t *t)
 {
   static struct tm y;
@@ -27362,10 +31426,10 @@ struct tm *__cdecl localtime(const time_t *t)
   sqlite3_int64 t64;
   t64 = *t;
   t64 = (t64 + 11644473600)*10000000;
-  uTm.dwLowDateTime = t64 & 0xFFFFFFFF;
-  uTm.dwHighDateTime= t64 >> 32;
-  FileTimeToLocalFileTime(&uTm,&lTm);
-  FileTimeToSystemTime(&lTm,&pTm);
+  uTm.dwLowDateTime = (DWORD)(t64 & 0xFFFFFFFF);
+  uTm.dwHighDateTime= (DWORD)(t64 >> 32);
+  osFileTimeToLocalFileTime(&uTm,&lTm);
+  osFileTimeToSystemTime(&lTm,&pTm);
   y.tm_year = pTm.wYear - 1900;
   y.tm_mon = pTm.wMonth - 1;
   y.tm_wday = pTm.wDayOfWeek;
@@ -27376,14 +31440,7 @@ struct tm *__cdecl localtime(const time_t *t)
   return &y;
 }
 
-/* This will never be called, but defined to make the code compile */
-#define GetTempPathA(a,b)
-
-#define LockFile(a,b,c,d,e)       winceLockFile(&a, b, c, d, e)
-#define UnlockFile(a,b,c,d,e)     winceUnlockFile(&a, b, c, d, e)
-#define LockFileEx(a,b,c,d,e,f)   winceLockFileEx(&a, b, c, d, e, f)
-
-#define HANDLE_TO_WINFILE(a) (winFile*)&((char*)a)[-offsetof(winFile,h)]
+#define HANDLE_TO_WINFILE(a) (winFile*)&((char*)a)[-(int)offsetof(winFile,h)]
 
 /*
 ** Acquire a lock on the handle h
@@ -27391,7 +31448,7 @@ struct tm *__cdecl localtime(const time_t *t)
 static void winceMutexAcquire(HANDLE h){
    DWORD dwErr;
    do {
-     dwErr = WaitForSingleObject(h, INFINITE);
+     dwErr = osWaitForSingleObject(h, INFINITE);
    } while (dwErr != WAIT_OBJECT_0 && dwErr != WAIT_ABANDONED);
 }
 /*
@@ -27404,24 +31461,32 @@ static void winceMutexAcquire(HANDLE h){
 ** descriptor pFile
 */
 static BOOL winceCreateLock(const char *zFilename, winFile *pFile){
-  WCHAR *zTok;
-  WCHAR *zName = utf8ToUnicode(zFilename);
+  LPWSTR zTok;
+  LPWSTR zName;
   BOOL bInit = TRUE;
 
+  zName = utf8ToUnicode(zFilename);
+  if( zName==0 ){
+    /* out of memory */
+    return FALSE;
+  }
+
   /* Initialize the local lockdata */
-  ZeroMemory(&pFile->local, sizeof(pFile->local));
+  memset(&pFile->local, 0, sizeof(pFile->local));
 
   /* Replace the backslashes from the filename and lowercase it
   ** to derive a mutex name. */
-  zTok = CharLowerW(zName);
+  zTok = osCharLowerW(zName);
   for (;*zTok;zTok++){
     if (*zTok == '\\') *zTok = '_';
   }
 
   /* Create/open the named mutex */
-  pFile->hMutex = CreateMutexW(NULL, FALSE, zName);
+  pFile->hMutex = osCreateMutexW(NULL, FALSE, zName);
   if (!pFile->hMutex){
-    free(zName);
+    pFile->lastErrno = osGetLastError();
+    winLogError(SQLITE_ERROR, pFile->lastErrno, "winceCreateLock1", zFilename);
+    sqlite3_free(zName);
     return FALSE;
   }
 
@@ -27432,26 +31497,29 @@ static BOOL winceCreateLock(const char *zFilename, winFile *pFile){
   ** case-sensitive, take advantage of that by uppercasing the mutex name
   ** and using that as the shared filemapping name.
   */
-  CharUpperW(zName);
-  pFile->hShared = CreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
-                                       PAGE_READWRITE, 0, sizeof(winceLock),
-                                       zName);  
+  osCharUpperW(zName);
+  pFile->hShared = osCreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
+                                        PAGE_READWRITE, 0, sizeof(winceLock),
+                                        zName);  
 
   /* Set a flag that indicates we're the first to create the memory so it 
   ** must be zero-initialized */
-  if (GetLastError() == ERROR_ALREADY_EXISTS){
+  if (osGetLastError() == ERROR_ALREADY_EXISTS){
     bInit = FALSE;
   }
 
-  free(zName);
+  sqlite3_free(zName);
 
   /* If we succeeded in making the shared memory handle, map it. */
   if (pFile->hShared){
-    pFile->shared = (winceLock*)MapViewOfFile(pFile->hShared, 
+    pFile->shared = (winceLock*)osMapViewOfFile(pFile->hShared, 
              FILE_MAP_READ|FILE_MAP_WRITE, 0, 0, sizeof(winceLock));
     /* If mapping failed, close the shared memory handle and erase it */
     if (!pFile->shared){
-      CloseHandle(pFile->hShared);
+      pFile->lastErrno = osGetLastError();
+      winLogError(SQLITE_ERROR, pFile->lastErrno,
+               "winceCreateLock2", zFilename);
+      osCloseHandle(pFile->hShared);
       pFile->hShared = NULL;
     }
   }
@@ -27459,14 +31527,14 @@ static BOOL winceCreateLock(const char *zFilename, winFile *pFile){
   /* If shared memory could not be created, then close the mutex and fail */
   if (pFile->hShared == NULL){
     winceMutexRelease(pFile->hMutex);
-    CloseHandle(pFile->hMutex);
+    osCloseHandle(pFile->hMutex);
     pFile->hMutex = NULL;
     return FALSE;
   }
   
   /* Initialize the shared memory if we're supposed to */
   if (bInit) {
-    ZeroMemory(pFile->shared, sizeof(winceLock));
+    memset(pFile->shared, 0, sizeof(winceLock));
   }
 
   winceMutexRelease(pFile->hMutex);
@@ -27497,21 +31565,21 @@ static void winceDestroyLock(winFile *pFile){
     }
 
     /* De-reference and close our copy of the shared memory handle */
-    UnmapViewOfFile(pFile->shared);
-    CloseHandle(pFile->hShared);
+    osUnmapViewOfFile(pFile->shared);
+    osCloseHandle(pFile->hShared);
 
     /* Done with the mutex */
     winceMutexRelease(pFile->hMutex);    
-    CloseHandle(pFile->hMutex);
+    osCloseHandle(pFile->hMutex);
     pFile->hMutex = NULL;
   }
 }
 
 /* 
-** An implementation of the LockFile() API of windows for wince
+** An implementation of the LockFile() API of Windows for CE
 */
 static BOOL winceLockFile(
-  HANDLE *phFile,
+  LPHANDLE phFile,
   DWORD dwFileOffsetLow,
   DWORD dwFileOffsetHigh,
   DWORD nNumberOfBytesToLockLow,
@@ -27520,12 +31588,15 @@ static BOOL winceLockFile(
   winFile *pFile = HANDLE_TO_WINFILE(phFile);
   BOOL bReturn = FALSE;
 
+  UNUSED_PARAMETER(dwFileOffsetHigh);
+  UNUSED_PARAMETER(nNumberOfBytesToLockHigh);
+
   if (!pFile->hMutex) return TRUE;
   winceMutexAcquire(pFile->hMutex);
 
   /* Wanting an exclusive lock? */
-  if (dwFileOffsetLow == SHARED_FIRST
-       && nNumberOfBytesToLockLow == SHARED_SIZE){
+  if (dwFileOffsetLow == (DWORD)SHARED_FIRST
+       && nNumberOfBytesToLockLow == (DWORD)SHARED_SIZE){
     if (pFile->shared->nReaders == 0 && pFile->shared->bExclusive == 0){
        pFile->shared->bExclusive = TRUE;
        pFile->local.bExclusive = TRUE;
@@ -27534,9 +31605,8 @@ static BOOL winceLockFile(
   }
 
   /* Want a read-only lock? */
-  else if ((dwFileOffsetLow >= SHARED_FIRST &&
-            dwFileOffsetLow < SHARED_FIRST + SHARED_SIZE) &&
-            nNumberOfBytesToLockLow == 1){
+  else if (dwFileOffsetLow == (DWORD)SHARED_FIRST &&
+           nNumberOfBytesToLockLow == 1){
     if (pFile->shared->bExclusive == 0){
       pFile->local.nReaders ++;
       if (pFile->local.nReaders == 1){
@@ -27547,7 +31617,7 @@ static BOOL winceLockFile(
   }
 
   /* Want a pending lock? */
-  else if (dwFileOffsetLow == PENDING_BYTE && nNumberOfBytesToLockLow == 1){
+  else if (dwFileOffsetLow == (DWORD)PENDING_BYTE && nNumberOfBytesToLockLow == 1){
     /* If no pending lock has been acquired, then acquire it */
     if (pFile->shared->bPending == 0) {
       pFile->shared->bPending = TRUE;
@@ -27555,8 +31625,9 @@ static BOOL winceLockFile(
       bReturn = TRUE;
     }
   }
+
   /* Want a reserved lock? */
-  else if (dwFileOffsetLow == RESERVED_BYTE && nNumberOfBytesToLockLow == 1){
+  else if (dwFileOffsetLow == (DWORD)RESERVED_BYTE && nNumberOfBytesToLockLow == 1){
     if (pFile->shared->bReserved == 0) {
       pFile->shared->bReserved = TRUE;
       pFile->local.bReserved = TRUE;
@@ -27569,10 +31640,10 @@ static BOOL winceLockFile(
 }
 
 /*
-** An implementation of the UnlockFile API of windows for wince
+** An implementation of the UnlockFile API of Windows for CE
 */
 static BOOL winceUnlockFile(
-  HANDLE *phFile,
+  LPHANDLE phFile,
   DWORD dwFileOffsetLow,
   DWORD dwFileOffsetHigh,
   DWORD nNumberOfBytesToUnlockLow,
@@ -27581,14 +31652,17 @@ static BOOL winceUnlockFile(
   winFile *pFile = HANDLE_TO_WINFILE(phFile);
   BOOL bReturn = FALSE;
 
+  UNUSED_PARAMETER(dwFileOffsetHigh);
+  UNUSED_PARAMETER(nNumberOfBytesToUnlockHigh);
+
   if (!pFile->hMutex) return TRUE;
   winceMutexAcquire(pFile->hMutex);
 
   /* Releasing a reader lock or an exclusive lock */
-  if (dwFileOffsetLow >= SHARED_FIRST &&
-       dwFileOffsetLow < SHARED_FIRST + SHARED_SIZE){
+  if (dwFileOffsetLow == (DWORD)SHARED_FIRST){
     /* Did we have an exclusive lock? */
     if (pFile->local.bExclusive){
+      assert(nNumberOfBytesToUnlockLow == (DWORD)SHARED_SIZE);
       pFile->local.bExclusive = FALSE;
       pFile->shared->bExclusive = FALSE;
       bReturn = TRUE;
@@ -27596,6 +31670,7 @@ static BOOL winceUnlockFile(
 
     /* Did we just have a reader lock? */
     else if (pFile->local.nReaders){
+      assert(nNumberOfBytesToUnlockLow == (DWORD)SHARED_SIZE || nNumberOfBytesToUnlockLow == 1);
       pFile->local.nReaders --;
       if (pFile->local.nReaders == 0)
       {
@@ -27606,7 +31681,7 @@ static BOOL winceUnlockFile(
   }
 
   /* Releasing a pending lock */
-  else if (dwFileOffsetLow == PENDING_BYTE && nNumberOfBytesToUnlockLow == 1){
+  else if (dwFileOffsetLow == (DWORD)PENDING_BYTE && nNumberOfBytesToUnlockLow == 1){
     if (pFile->local.bPending){
       pFile->local.bPending = FALSE;
       pFile->shared->bPending = FALSE;
@@ -27614,7 +31689,7 @@ static BOOL winceUnlockFile(
     }
   }
   /* Releasing a reserved lock */
-  else if (dwFileOffsetLow == RESERVED_BYTE && nNumberOfBytesToUnlockLow == 1){
+  else if (dwFileOffsetLow == (DWORD)RESERVED_BYTE && nNumberOfBytesToUnlockLow == 1){
     if (pFile->local.bReserved) {
       pFile->local.bReserved = FALSE;
       pFile->shared->bReserved = FALSE;
@@ -27625,42 +31700,146 @@ static BOOL winceUnlockFile(
   winceMutexRelease(pFile->hMutex);
   return bReturn;
 }
-
-/*
-** An implementation of the LockFileEx() API of windows for wince
-*/
-static BOOL winceLockFileEx(
-  HANDLE *phFile,
-  DWORD dwFlags,
-  DWORD dwReserved,
-  DWORD nNumberOfBytesToLockLow,
-  DWORD nNumberOfBytesToLockHigh,
-  LPOVERLAPPED lpOverlapped
-){
-  /* If the caller wants a shared read lock, forward this call
-  ** to winceLockFile */
-  if (lpOverlapped->Offset == SHARED_FIRST &&
-      dwFlags == 1 &&
-      nNumberOfBytesToLockLow == SHARED_SIZE){
-    return winceLockFile(phFile, SHARED_FIRST, 0, 1, 0);
-  }
-  return FALSE;
-}
 /*
 ** End of the special code for wince
 *****************************************************************************/
 #endif /* SQLITE_OS_WINCE */
 
+/*
+** Lock a file region.
+*/
+static BOOL winLockFile(
+  LPHANDLE phFile,
+  DWORD flags,
+  DWORD offsetLow,
+  DWORD offsetHigh,
+  DWORD numBytesLow,
+  DWORD numBytesHigh
+){
+#if SQLITE_OS_WINCE
+  /*
+  ** NOTE: Windows CE is handled differently here due its lack of the Win32
+  **       API LockFile.
+  */
+  return winceLockFile(phFile, offsetLow, offsetHigh,
+                       numBytesLow, numBytesHigh);
+#else
+  if( isNT() ){
+    OVERLAPPED ovlp;
+    memset(&ovlp, 0, sizeof(OVERLAPPED));
+    ovlp.Offset = offsetLow;
+    ovlp.OffsetHigh = offsetHigh;
+    return osLockFileEx(*phFile, flags, 0, numBytesLow, numBytesHigh, &ovlp);
+  }else{
+    return osLockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
+                      numBytesHigh);
+  }
+#endif
+}
+
+/*
+** Unlock a file region.
+ */
+static BOOL winUnlockFile(
+  LPHANDLE phFile,
+  DWORD offsetLow,
+  DWORD offsetHigh,
+  DWORD numBytesLow,
+  DWORD numBytesHigh
+){
+#if SQLITE_OS_WINCE
+  /*
+  ** NOTE: Windows CE is handled differently here due its lack of the Win32
+  **       API UnlockFile.
+  */
+  return winceUnlockFile(phFile, offsetLow, offsetHigh,
+                         numBytesLow, numBytesHigh);
+#else
+  if( isNT() ){
+    OVERLAPPED ovlp;
+    memset(&ovlp, 0, sizeof(OVERLAPPED));
+    ovlp.Offset = offsetLow;
+    ovlp.OffsetHigh = offsetHigh;
+    return osUnlockFileEx(*phFile, 0, numBytesLow, numBytesHigh, &ovlp);
+  }else{
+    return osUnlockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
+                        numBytesHigh);
+  }
+#endif
+}
+
 /*****************************************************************************
 ** The next group of routines implement the I/O methods specified
 ** by the sqlite3_io_methods object.
 ******************************************************************************/
 
+/*
+** Some Microsoft compilers lack this definition.
+*/
+#ifndef INVALID_SET_FILE_POINTER
+# define INVALID_SET_FILE_POINTER ((DWORD)-1)
+#endif
+
+/*
+** Move the current position of the file handle passed as the first 
+** argument to offset iOffset within the file. If successful, return 0. 
+** Otherwise, set pFile->lastErrno and return non-zero.
+*/
+static int seekWinFile(winFile *pFile, sqlite3_int64 iOffset){
+#if !SQLITE_OS_WINRT
+  LONG upperBits;                 /* Most sig. 32 bits of new offset */
+  LONG lowerBits;                 /* Least sig. 32 bits of new offset */
+  DWORD dwRet;                    /* Value returned by SetFilePointer() */
+  DWORD lastErrno;                /* Value returned by GetLastError() */
+
+  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
+  lowerBits = (LONG)(iOffset & 0xffffffff);
+
+  /* API oddity: If successful, SetFilePointer() returns a dword 
+  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
+  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN, 
+  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine 
+  ** whether an error has actually occured, it is also necessary to call 
+  ** GetLastError().
+  */
+  dwRet = osSetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
+
+  if( (dwRet==INVALID_SET_FILE_POINTER
+      && ((lastErrno = osGetLastError())!=NO_ERROR)) ){
+    pFile->lastErrno = lastErrno;
+    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
+             "seekWinFile", pFile->zPath);
+    return 1;
+  }
+
+  return 0;
+#else
+  /*
+  ** Same as above, except that this implementation works for WinRT.
+  */
+
+  LARGE_INTEGER x;                /* The new offset */
+  BOOL bRet;                      /* Value returned by SetFilePointerEx() */
+
+  x.QuadPart = iOffset;
+  bRet = osSetFilePointerEx(pFile->h, x, 0, FILE_BEGIN);
+
+  if(!bRet){
+    pFile->lastErrno = osGetLastError();
+    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
+             "seekWinFile", pFile->zPath);
+    return 1;
+  }
+
+  return 0;
+#endif
+}
+
 /*
 ** Close a file.
 **
 ** It is reported that an attempt to close a handle might sometimes
-** fail.  This is a very unreasonable result, but windows is notorious
+** fail.  This is a very unreasonable result, but Windows is notorious
 ** for being unreasonable so I do not doubt that it might happen.  If
 ** the close fails, we pause for 100 milliseconds and try again.  As
 ** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
@@ -27670,36 +31849,41 @@ static BOOL winceLockFileEx(
 static int winClose(sqlite3_file *id){
   int rc, cnt = 0;
   winFile *pFile = (winFile*)id;
-  OSTRACE2("CLOSE %d\n", pFile->h);
+
+  assert( id!=0 );
+#ifndef SQLITE_OMIT_WAL
+  assert( pFile->pShm==0 );
+#endif
+  OSTRACE(("CLOSE %d\n", pFile->h));
   do{
-    rc = CloseHandle(pFile->h);
-  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (Sleep(100), 1) );
+    rc = osCloseHandle(pFile->h);
+    /* SimulateIOError( rc=0; cnt=MX_CLOSE_ATTEMPT; ); */
+  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (sqlite3_win32_sleep(100), 1) );
 #if SQLITE_OS_WINCE
 #define WINCE_DELETION_ATTEMPTS 3
   winceDestroyLock(pFile);
   if( pFile->zDeleteOnClose ){
     int cnt = 0;
     while(
-           DeleteFileW(pFile->zDeleteOnClose)==0
-        && GetFileAttributesW(pFile->zDeleteOnClose)!=0xffffffff 
+           osDeleteFileW(pFile->zDeleteOnClose)==0
+        && osGetFileAttributesW(pFile->zDeleteOnClose)!=0xffffffff 
         && cnt++ < WINCE_DELETION_ATTEMPTS
     ){
-       Sleep(100);  /* Wait a little before trying again */
+       sqlite3_win32_sleep(100);  /* Wait a little before trying again */
     }
-    free(pFile->zDeleteOnClose);
+    sqlite3_free(pFile->zDeleteOnClose);
   }
 #endif
+  OSTRACE(("CLOSE %d %s\n", pFile->h, rc ? "ok" : "failed"));
+  if( rc ){
+    pFile->h = NULL;
+  }
   OpenCounter(-1);
-  return rc ? SQLITE_OK : SQLITE_IOERR;
+  return rc ? SQLITE_OK
+            : winLogError(SQLITE_IOERR_CLOSE, osGetLastError(),
+                          "winClose", pFile->zPath);
 }
 
-/*
-** Some microsoft compilers lack this definition.
-*/
-#ifndef INVALID_SET_FILE_POINTER
-# define INVALID_SET_FILE_POINTER ((DWORD)-1)
-#endif
-
 /*
 ** Read data from a file into a buffer.  Return SQLITE_OK if all
 ** bytes were read successfully and SQLITE_IOERR if anything goes
@@ -27711,28 +31895,43 @@ static int winRead(
   int amt,                   /* Number of bytes to read */
   sqlite3_int64 offset       /* Begin reading at this offset */
 ){
-  LONG upperBits = (LONG)((offset>>32) & 0x7fffffff);
-  LONG lowerBits = (LONG)(offset & 0xffffffff);
-  DWORD rc;
-  DWORD got;
-  winFile *pFile = (winFile*)id;
+#if !SQLITE_OS_WINCE
+  OVERLAPPED overlapped;          /* The offset for ReadFile. */
+#endif
+  winFile *pFile = (winFile*)id;  /* file handle */
+  DWORD nRead;                    /* Number of bytes actually read from file */
+  int nRetry = 0;                 /* Number of retrys */
+
   assert( id!=0 );
   SimulateIOError(return SQLITE_IOERR_READ);
-  OSTRACE3("READ %d lock=%d\n", pFile->h, pFile->locktype);
-  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
-  if( rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR ){
+  OSTRACE(("READ %d lock=%d\n", pFile->h, pFile->locktype));
+
+#if SQLITE_OS_WINCE
+  if( seekWinFile(pFile, offset) ){
     return SQLITE_FULL;
   }
-  if( !ReadFile(pFile->h, pBuf, amt, &got, 0) ){
-    return SQLITE_IOERR_READ;
+  while( !osReadFile(pFile->h, pBuf, amt, &nRead, 0) ){
+#else
+  memset(&overlapped, 0, sizeof(OVERLAPPED));
+  overlapped.Offset = (LONG)(offset & 0xffffffff);
+  overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+  while( !osReadFile(pFile->h, pBuf, amt, &nRead, &overlapped) &&
+         osGetLastError()!=ERROR_HANDLE_EOF ){
+#endif
+    DWORD lastErrno;
+    if( retryIoerr(&nRetry, &lastErrno) ) continue;
+    pFile->lastErrno = lastErrno;
+    return winLogError(SQLITE_IOERR_READ, pFile->lastErrno,
+             "winRead", pFile->zPath);
   }
-  if( got==(DWORD)amt ){
-    return SQLITE_OK;
-  }else{
+  logIoerr(nRetry);
+  if( nRead<(DWORD)amt ){
     /* Unread parts of the buffer must be zero-filled */
-    memset(&((char*)pBuf)[got], 0, amt-got);
+    memset(&((char*)pBuf)[nRead], 0, amt-nRead);
     return SQLITE_IOERR_SHORT_READ;
   }
+
+  return SQLITE_OK;
 }
 
 /*
@@ -27740,35 +31939,78 @@ static int winRead(
 ** or some other error code on failure.
 */
 static int winWrite(
-  sqlite3_file *id,         /* File to write into */
-  const void *pBuf,         /* The bytes to be written */
-  int amt,                  /* Number of bytes to write */
-  sqlite3_int64 offset      /* Offset into the file to begin writing at */
+  sqlite3_file *id,               /* File to write into */
+  const void *pBuf,               /* The bytes to be written */
+  int amt,                        /* Number of bytes to write */
+  sqlite3_int64 offset            /* Offset into the file to begin writing at */
 ){
-  LONG upperBits = (LONG)((offset>>32) & 0x7fffffff);
-  LONG lowerBits = (LONG)(offset & 0xffffffff);
-  DWORD rc;
-  DWORD wrote = 0;
-  winFile *pFile = (winFile*)id;
-  assert( id!=0 );
+  int rc = 0;                     /* True if error has occured, else false */
+  winFile *pFile = (winFile*)id;  /* File handle */
+  int nRetry = 0;                 /* Number of retries */
+
+  assert( amt>0 );
+  assert( pFile );
   SimulateIOError(return SQLITE_IOERR_WRITE);
   SimulateDiskfullError(return SQLITE_FULL);
-  OSTRACE3("WRITE %d lock=%d\n", pFile->h, pFile->locktype);
-  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
-  if( rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR ){
-    return SQLITE_FULL;
+
+  OSTRACE(("WRITE %d lock=%d\n", pFile->h, pFile->locktype));
+
+#if SQLITE_OS_WINCE
+  rc = seekWinFile(pFile, offset);
+  if( rc==0 ){
+#else
+  {
+#endif
+#if !SQLITE_OS_WINCE
+    OVERLAPPED overlapped;        /* The offset for WriteFile. */
+#endif
+    u8 *aRem = (u8 *)pBuf;        /* Data yet to be written */
+    int nRem = amt;               /* Number of bytes yet to be written */
+    DWORD nWrite;                 /* Bytes written by each WriteFile() call */
+    DWORD lastErrno = NO_ERROR;   /* Value returned by GetLastError() */
+
+#if !SQLITE_OS_WINCE
+    memset(&overlapped, 0, sizeof(OVERLAPPED));
+    overlapped.Offset = (LONG)(offset & 0xffffffff);
+    overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+#endif
+
+    while( nRem>0 ){
+#if SQLITE_OS_WINCE
+      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, 0) ){
+#else
+      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, &overlapped) ){
+#endif
+        if( retryIoerr(&nRetry, &lastErrno) ) continue;
+        break;
+      }
+      if( nWrite<=0 ){
+        lastErrno = osGetLastError();
+        break;
+      }
+#if !SQLITE_OS_WINCE
+      offset += nWrite;
+      overlapped.Offset = (LONG)(offset & 0xffffffff);
+      overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+#endif
+      aRem += nWrite;
+      nRem -= nWrite;
+    }
+    if( nRem>0 ){
+      pFile->lastErrno = lastErrno;
+      rc = 1;
+    }
   }
-  assert( amt>0 );
-  while(
-     amt>0
-     && (rc = WriteFile(pFile->h, pBuf, amt, &wrote, 0))!=0
-     && wrote>0
-  ){
-    amt -= wrote;
-    pBuf = &((char*)pBuf)[wrote];
-  }
-  if( !rc || amt>(int)wrote ){
-    return SQLITE_FULL;
+
+  if( rc ){
+    if(   ( pFile->lastErrno==ERROR_HANDLE_DISK_FULL )
+       || ( pFile->lastErrno==ERROR_DISK_FULL )){
+      return SQLITE_FULL;
+    }
+    return winLogError(SQLITE_IOERR_WRITE, pFile->lastErrno,
+             "winWrite", pFile->zPath);
+  }else{
+    logIoerr(nRetry);
   }
   return SQLITE_OK;
 }
@@ -27777,20 +32019,35 @@ static int winWrite(
 ** Truncate an open file to a specified size
 */
 static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
-  DWORD rc;
-  LONG upperBits = (LONG)((nByte>>32) & 0x7fffffff);
-  LONG lowerBits = (LONG)(nByte & 0xffffffff);
-  winFile *pFile = (winFile*)id;
-  OSTRACE3("TRUNCATE %d %lld\n", pFile->h, nByte);
+  winFile *pFile = (winFile*)id;  /* File handle object */
+  int rc = SQLITE_OK;             /* Return code for this function */
+
+  assert( pFile );
+
+  OSTRACE(("TRUNCATE %d %lld\n", pFile->h, nByte));
   SimulateIOError(return SQLITE_IOERR_TRUNCATE);
-  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
-  if( INVALID_SET_FILE_POINTER != rc ){
-    /* SetEndOfFile will fail if nByte is negative */
-    if( SetEndOfFile(pFile->h) ){
-      return SQLITE_OK;
-    }
+
+  /* If the user has configured a chunk-size for this file, truncate the
+  ** file so that it consists of an integer number of chunks (i.e. the
+  ** actual file size after the operation may be larger than the requested
+  ** size).
+  */
+  if( pFile->szChunk>0 ){
+    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
   }
-  return SQLITE_IOERR_TRUNCATE;
+
+  /* SetEndOfFile() returns non-zero when successful, or zero when it fails. */
+  if( seekWinFile(pFile, nByte) ){
+    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
+             "winTruncate1", pFile->zPath);
+  }else if( 0==osSetEndOfFile(pFile->h) ){
+    pFile->lastErrno = osGetLastError();
+    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
+             "winTruncate2", pFile->zPath);
+  }
+
+  OSTRACE(("TRUNCATE %d %lld %s\n", pFile->h, nByte, rc ? "failed" : "ok"));
+  return rc;
 }
 
 #ifdef SQLITE_TEST
@@ -27807,29 +32064,58 @@ SQLITE_API int sqlite3_fullsync_count = 0;
 */
 static int winSync(sqlite3_file *id, int flags){
 #ifndef SQLITE_NO_SYNC
+  /*
+  ** Used only when SQLITE_NO_SYNC is not defined.
+   */
+  BOOL rc;
+#endif
+#if !defined(NDEBUG) || !defined(SQLITE_NO_SYNC) || \
+    (defined(SQLITE_TEST) && defined(SQLITE_DEBUG))
+  /*
+  ** Used when SQLITE_NO_SYNC is not defined and by the assert() and/or
+  ** OSTRACE() macros.
+   */
   winFile *pFile = (winFile*)id;
 #else
   UNUSED_PARAMETER(id);
 #endif
-  OSTRACE3("SYNC %d lock=%d\n", pFile->h, pFile->locktype);
+
+  assert( pFile );
+  /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */
+  assert((flags&0x0F)==SQLITE_SYNC_NORMAL
+      || (flags&0x0F)==SQLITE_SYNC_FULL
+  );
+
+  OSTRACE(("SYNC %d lock=%d\n", pFile->h, pFile->locktype));
+
+  /* Unix cannot, but some systems may return SQLITE_FULL from here. This
+  ** line is to test that doing so does not cause any problems.
+  */
+  SimulateDiskfullError( return SQLITE_FULL );
+
 #ifndef SQLITE_TEST
   UNUSED_PARAMETER(flags);
 #else
-  if( flags & SQLITE_SYNC_FULL ){
+  if( (flags&0x0F)==SQLITE_SYNC_FULL ){
     sqlite3_fullsync_count++;
   }
   sqlite3_sync_count++;
 #endif
+
   /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
   ** no-op
   */
 #ifdef SQLITE_NO_SYNC
-    return SQLITE_OK;
+  return SQLITE_OK;
 #else
-  if( FlushFileBuffers(pFile->h) ){
+  rc = osFlushFileBuffers(pFile->h);
+  SimulateIOError( rc=FALSE );
+  if( rc ){
     return SQLITE_OK;
   }else{
-    return SQLITE_IOERR;
+    pFile->lastErrno = osGetLastError();
+    return winLogError(SQLITE_IOERR_FSYNC, pFile->lastErrno,
+             "winSync", pFile->zPath);
   }
 #endif
 }
@@ -27839,11 +32125,39 @@ static int winSync(sqlite3_file *id, int flags){
 */
 static int winFileSize(sqlite3_file *id, sqlite3_int64 *pSize){
   winFile *pFile = (winFile*)id;
-  DWORD upperBits, lowerBits;
+  int rc = SQLITE_OK;
+
+  assert( id!=0 );
   SimulateIOError(return SQLITE_IOERR_FSTAT);
-  lowerBits = GetFileSize(pFile->h, &upperBits);
-  *pSize = (((sqlite3_int64)upperBits)<<32) + lowerBits;
-  return SQLITE_OK;
+#if SQLITE_OS_WINRT
+  {
+    FILE_STANDARD_INFO info;
+    if( osGetFileInformationByHandleEx(pFile->h, FileStandardInfo,
+                                     &info, sizeof(info)) ){
+      *pSize = info.EndOfFile.QuadPart;
+    }else{
+      pFile->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
+                       "winFileSize", pFile->zPath);
+    }
+  }
+#else
+  {
+    DWORD upperBits;
+    DWORD lowerBits;
+    DWORD lastErrno;
+
+    lowerBits = osGetFileSize(pFile->h, &upperBits);
+    *pSize = (((sqlite3_int64)upperBits)<<32) + lowerBits;
+    if(   (lowerBits == INVALID_FILE_SIZE)
+       && ((lastErrno = osGetLastError())!=NO_ERROR) ){
+      pFile->lastErrno = lastErrno;
+      rc = winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
+             "winFileSize", pFile->zPath);
+    }
+  }
+#endif
+  return rc;
 }
 
 /*
@@ -27853,29 +32167,61 @@ static int winFileSize(sqlite3_file *id, sqlite3_int64 *pSize){
 # define LOCKFILE_FAIL_IMMEDIATELY 1
 #endif
 
+#ifndef LOCKFILE_EXCLUSIVE_LOCK
+# define LOCKFILE_EXCLUSIVE_LOCK 2
+#endif
+
+/*
+** Historically, SQLite has used both the LockFile and LockFileEx functions.
+** When the LockFile function was used, it was always expected to fail
+** immediately if the lock could not be obtained.  Also, it always expected to
+** obtain an exclusive lock.  These flags are used with the LockFileEx function
+** and reflect those expectations; therefore, they should not be changed.
+*/
+#ifndef SQLITE_LOCKFILE_FLAGS
+# define SQLITE_LOCKFILE_FLAGS   (LOCKFILE_FAIL_IMMEDIATELY | \
+                                  LOCKFILE_EXCLUSIVE_LOCK)
+#endif
+
+/*
+** Currently, SQLite never calls the LockFileEx function without wanting the
+** call to fail immediately if the lock cannot be obtained.
+*/
+#ifndef SQLITE_LOCKFILEEX_FLAGS
+# define SQLITE_LOCKFILEEX_FLAGS (LOCKFILE_FAIL_IMMEDIATELY)
+#endif
+
 /*
 ** Acquire a reader lock.
 ** Different API routines are called depending on whether or not this
-** is Win95 or WinNT.
+** is Win9x or WinNT.
 */
 static int getReadLock(winFile *pFile){
   int res;
   if( isNT() ){
-    OVERLAPPED ovlp;
-    ovlp.Offset = SHARED_FIRST;
-    ovlp.OffsetHigh = 0;
-    ovlp.hEvent = 0;
-    res = LockFileEx(pFile->h, LOCKFILE_FAIL_IMMEDIATELY,
-                     0, SHARED_SIZE, 0, &ovlp);
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
+#if SQLITE_OS_WINCE
+    /*
+    ** NOTE: Windows CE is handled differently here due its lack of the Win32
+    **       API LockFileEx.
+    */
+    res = winceLockFile(&pFile->h, SHARED_FIRST, 0, 1, 0);
+#else
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILEEX_FLAGS, SHARED_FIRST, 0,
+                      SHARED_SIZE, 0);
+#endif
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
     int lk;
     sqlite3_randomness(sizeof(lk), &lk);
     pFile->sharedLockByte = (short)((lk & 0x7fffffff)%(SHARED_SIZE - 1));
-    res = LockFile(pFile->h, SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS,
+                      SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+  }
 #endif
+  if( res == 0 ){
+    pFile->lastErrno = osGetLastError();
+    /* No need to log a failure to lock */
   }
   return res;
 }
@@ -27885,14 +32231,19 @@ static int getReadLock(winFile *pFile){
 */
 static int unlockReadLock(winFile *pFile){
   int res;
+  DWORD lastErrno;
   if( isNT() ){
-    res = UnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
-    res = UnlockFile(pFile->h, SHARED_FIRST + pFile->sharedLockByte, 0, 1, 0);
+    res = winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    res = winUnlockFile(&pFile->h, SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+  }
 #endif
+  if( res==0 && ((lastErrno = osGetLastError())!=ERROR_NOT_LOCKED) ){
+    pFile->lastErrno = lastErrno;
+    winLogError(SQLITE_IOERR_UNLOCK, pFile->lastErrno,
+             "unlockReadLock", pFile->zPath);
   }
   return res;
 }
@@ -27925,14 +32276,15 @@ static int unlockReadLock(winFile *pFile){
 */
 static int winLock(sqlite3_file *id, int locktype){
   int rc = SQLITE_OK;    /* Return code from subroutines */
-  int res = 1;           /* Result of a windows lock call */
+  int res = 1;           /* Result of a Windows lock call */
   int newLocktype;       /* Set pFile->locktype to this value before exiting */
   int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
   winFile *pFile = (winFile*)id;
+  DWORD lastErrno = NO_ERROR;
 
-  assert( pFile!=0 );
-  OSTRACE5("LOCK %d %d was %d(%d)\n",
-          pFile->h, locktype, pFile->locktype, pFile->sharedLockByte);
+  assert( id!=0 );
+  OSTRACE(("LOCK %d %d was %d(%d)\n",
+           pFile->h, locktype, pFile->locktype, pFile->sharedLockByte));
 
   /* If there is already a lock of this type or more restrictive on the
   ** OsFile, do nothing. Don't use the end_lock: exit path, as
@@ -27953,18 +32305,26 @@ static int winLock(sqlite3_file *id, int locktype){
   ** the PENDING_LOCK byte is temporary.
   */
   newLocktype = pFile->locktype;
-  if( pFile->locktype==NO_LOCK
-   || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
+  if(   (pFile->locktype==NO_LOCK)
+     || (   (locktype==EXCLUSIVE_LOCK)
+         && (pFile->locktype==RESERVED_LOCK))
   ){
     int cnt = 3;
-    while( cnt-->0 && (res = LockFile(pFile->h, PENDING_BYTE, 0, 1, 0))==0 ){
-      /* Try 3 times to get the pending lock.  The pending lock might be
-      ** held by another reader process who will release it momentarily.
+    while( cnt-->0 && (res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS,
+                                         PENDING_BYTE, 0, 1, 0))==0 ){
+      /* Try 3 times to get the pending lock.  This is needed to work
+      ** around problems caused by indexing and/or anti-virus software on
+      ** Windows systems.
+      ** If you are using this code as a model for alternative VFSes, do not
+      ** copy this retry logic.  It is a hack intended for Windows only.
       */
-      OSTRACE2("could not get a PENDING lock. cnt=%d\n", cnt);
-      Sleep(1);
+      OSTRACE(("could not get a PENDING lock. cnt=%d\n", cnt));
+      if( cnt ) sqlite3_win32_sleep(1);
     }
     gotPendingLock = res;
+    if( !res ){
+      lastErrno = osGetLastError();
+    }
   }
 
   /* Acquire a shared lock
@@ -27974,6 +32334,8 @@ static int winLock(sqlite3_file *id, int locktype){
     res = getReadLock(pFile);
     if( res ){
       newLocktype = SHARED_LOCK;
+    }else{
+      lastErrno = osGetLastError();
     }
   }
 
@@ -27981,9 +32343,11 @@ static int winLock(sqlite3_file *id, int locktype){
   */
   if( locktype==RESERVED_LOCK && res ){
     assert( pFile->locktype==SHARED_LOCK );
-    res = LockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, RESERVED_BYTE, 0, 1, 0);
     if( res ){
       newLocktype = RESERVED_LOCK;
+    }else{
+      lastErrno = osGetLastError();
     }
   }
 
@@ -27999,12 +32363,14 @@ static int winLock(sqlite3_file *id, int locktype){
   if( locktype==EXCLUSIVE_LOCK && res ){
     assert( pFile->locktype>=SHARED_LOCK );
     res = unlockReadLock(pFile);
-    OSTRACE2("unreadlock = %d\n", res);
-    res = LockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+    OSTRACE(("unreadlock = %d\n", res));
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, SHARED_FIRST, 0,
+                      SHARED_SIZE, 0);
     if( res ){
       newLocktype = EXCLUSIVE_LOCK;
     }else{
-      OSTRACE2("error-code = %d\n", GetLastError());
+      lastErrno = osGetLastError();
+      OSTRACE(("error-code = %d\n", lastErrno));
       getReadLock(pFile);
     }
   }
@@ -28013,7 +32379,7 @@ static int winLock(sqlite3_file *id, int locktype){
   ** release it now.
   */
   if( gotPendingLock && locktype==SHARED_LOCK ){
-    UnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
+    winUnlockFile(&pFile->h, PENDING_BYTE, 0, 1, 0);
   }
 
   /* Update the state of the lock has held in the file descriptor then
@@ -28022,8 +32388,9 @@ static int winLock(sqlite3_file *id, int locktype){
   if( res ){
     rc = SQLITE_OK;
   }else{
-    OSTRACE4("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
-           locktype, newLocktype);
+    OSTRACE(("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
+           locktype, newLocktype));
+    pFile->lastErrno = lastErrno;
     rc = SQLITE_BUSY;
   }
   pFile->locktype = (u8)newLocktype;
@@ -28038,17 +32405,20 @@ static int winLock(sqlite3_file *id, int locktype){
 static int winCheckReservedLock(sqlite3_file *id, int *pResOut){
   int rc;
   winFile *pFile = (winFile*)id;
-  assert( pFile!=0 );
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( id!=0 );
   if( pFile->locktype>=RESERVED_LOCK ){
     rc = 1;
-    OSTRACE3("TEST WR-LOCK %d %d (local)\n", pFile->h, rc);
+    OSTRACE(("TEST WR-LOCK %d %d (local)\n", pFile->h, rc));
   }else{
-    rc = LockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+    rc = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, RESERVED_BYTE, 0, 1, 0);
     if( rc ){
-      UnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+      winUnlockFile(&pFile->h, RESERVED_BYTE, 0, 1, 0);
     }
     rc = !rc;
-    OSTRACE3("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc);
+    OSTRACE(("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc));
   }
   *pResOut = rc;
   return SQLITE_OK;
@@ -28071,41 +32441,109 @@ static int winUnlock(sqlite3_file *id, int locktype){
   int rc = SQLITE_OK;
   assert( pFile!=0 );
   assert( locktype<=SHARED_LOCK );
-  OSTRACE5("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
-          pFile->locktype, pFile->sharedLockByte);
+  OSTRACE(("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
+          pFile->locktype, pFile->sharedLockByte));
   type = pFile->locktype;
   if( type>=EXCLUSIVE_LOCK ){
-    UnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+    winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
     if( locktype==SHARED_LOCK && !getReadLock(pFile) ){
       /* This should never happen.  We should always be able to
       ** reacquire the read lock */
-      rc = SQLITE_IOERR_UNLOCK;
+      rc = winLogError(SQLITE_IOERR_UNLOCK, osGetLastError(),
+               "winUnlock", pFile->zPath);
     }
   }
   if( type>=RESERVED_LOCK ){
-    UnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
+    winUnlockFile(&pFile->h, RESERVED_BYTE, 0, 1, 0);
   }
   if( locktype==NO_LOCK && type>=SHARED_LOCK ){
     unlockReadLock(pFile);
   }
   if( type>=PENDING_LOCK ){
-    UnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
+    winUnlockFile(&pFile->h, PENDING_BYTE, 0, 1, 0);
   }
   pFile->locktype = (u8)locktype;
   return rc;
 }
 
+/*
+** If *pArg is inititially negative then this is a query.  Set *pArg to
+** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
+**
+** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
+*/
+static void winModeBit(winFile *pFile, unsigned char mask, int *pArg){
+  if( *pArg<0 ){
+    *pArg = (pFile->ctrlFlags & mask)!=0;
+  }else if( (*pArg)==0 ){
+    pFile->ctrlFlags &= ~mask;
+  }else{
+    pFile->ctrlFlags |= mask;
+  }
+}
+
 /*
 ** Control and query of the open file handle.
 */
 static int winFileControl(sqlite3_file *id, int op, void *pArg){
+  winFile *pFile = (winFile*)id;
   switch( op ){
     case SQLITE_FCNTL_LOCKSTATE: {
-      *(int*)pArg = ((winFile*)id)->locktype;
+      *(int*)pArg = pFile->locktype;
+      return SQLITE_OK;
+    }
+    case SQLITE_LAST_ERRNO: {
+      *(int*)pArg = (int)pFile->lastErrno;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_CHUNK_SIZE: {
+      pFile->szChunk = *(int *)pArg;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SIZE_HINT: {
+      if( pFile->szChunk>0 ){
+        sqlite3_int64 oldSz;
+        int rc = winFileSize(id, &oldSz);
+        if( rc==SQLITE_OK ){
+          sqlite3_int64 newSz = *(sqlite3_int64*)pArg;
+          if( newSz>oldSz ){
+            SimulateIOErrorBenign(1);
+            rc = winTruncate(id, newSz);
+            SimulateIOErrorBenign(0);
+          }
+        }
+        return rc;
+      }
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      winModeBit(pFile, WINFILE_PERSIST_WAL, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
+      winModeBit(pFile, WINFILE_PSOW, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_VFSNAME: {
+      *(char**)pArg = sqlite3_mprintf("win32");
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_WIN32_AV_RETRY: {
+      int *a = (int*)pArg;
+      if( a[0]>0 ){
+        win32IoerrRetry = a[0];
+      }else{
+        a[0] = win32IoerrRetry;
+      }
+      if( a[1]>0 ){
+        win32IoerrRetryDelay = a[1];
+      }else{
+        a[1] = win32IoerrRetryDelay;
+      }
       return SQLITE_OK;
     }
   }
-  return SQLITE_ERROR;
+  return SQLITE_NOTFOUND;
 }
 
 /*
@@ -28119,7 +32557,7 @@ static int winFileControl(sqlite3_file *id, int op, void *pArg){
 ** same for both.
 */
 static int winSectorSize(sqlite3_file *id){
-  UNUSED_PARAMETER(id);
+  (void)id;
   return SQLITE_DEFAULT_SECTOR_SIZE;
 }
 
@@ -28127,35 +32565,687 @@ static int winSectorSize(sqlite3_file *id){
 ** Return a vector of device characteristics.
 */
 static int winDeviceCharacteristics(sqlite3_file *id){
-  UNUSED_PARAMETER(id);
-  return 0;
+  winFile *p = (winFile*)id;
+  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN |
+         ((p->ctrlFlags & WINFILE_PSOW)?SQLITE_IOCAP_POWERSAFE_OVERWRITE:0);
 }
 
+#ifndef SQLITE_OMIT_WAL
+
+/* 
+** Windows will only let you create file view mappings
+** on allocation size granularity boundaries.
+** During sqlite3_os_init() we do a GetSystemInfo()
+** to get the granularity size.
+*/
+SYSTEM_INFO winSysInfo;
+
+/*
+** Helper functions to obtain and relinquish the global mutex. The
+** global mutex is used to protect the winLockInfo objects used by 
+** this file, all of which may be shared by multiple threads.
+**
+** Function winShmMutexHeld() is used to assert() that the global mutex 
+** is held when required. This function is only used as part of assert() 
+** statements. e.g.
+**
+**   winShmEnterMutex()
+**     assert( winShmMutexHeld() );
+**   winShmLeaveMutex()
+*/
+static void winShmEnterMutex(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+static void winShmLeaveMutex(void){
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+#ifdef SQLITE_DEBUG
+static int winShmMutexHeld(void) {
+  return sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+#endif
+
+/*
+** Object used to represent a single file opened and mmapped to provide
+** shared memory.  When multiple threads all reference the same
+** log-summary, each thread has its own winFile object, but they all
+** point to a single instance of this object.  In other words, each
+** log-summary is opened only once per process.
+**
+** winShmMutexHeld() must be true when creating or destroying
+** this object or while reading or writing the following fields:
+**
+**      nRef
+**      pNext 
+**
+** The following fields are read-only after the object is created:
+** 
+**      fid
+**      zFilename
+**
+** Either winShmNode.mutex must be held or winShmNode.nRef==0 and
+** winShmMutexHeld() is true when reading or writing any other field
+** in this structure.
+**
+*/
+struct winShmNode {
+  sqlite3_mutex *mutex;      /* Mutex to access this object */
+  char *zFilename;           /* Name of the file */
+  winFile hFile;             /* File handle from winOpen */
+
+  int szRegion;              /* Size of shared-memory regions */
+  int nRegion;               /* Size of array apRegion */
+  struct ShmRegion {
+    HANDLE hMap;             /* File handle from CreateFileMapping */
+    void *pMap;
+  } *aRegion;
+  DWORD lastErrno;           /* The Windows errno from the last I/O error */
+
+  int nRef;                  /* Number of winShm objects pointing to this */
+  winShm *pFirst;            /* All winShm objects pointing to this */
+  winShmNode *pNext;         /* Next in list of all winShmNode objects */
+#ifdef SQLITE_DEBUG
+  u8 nextShmId;              /* Next available winShm.id value */
+#endif
+};
+
+/*
+** A global array of all winShmNode objects.
+**
+** The winShmMutexHeld() must be true while reading or writing this list.
+*/
+static winShmNode *winShmNodeList = 0;
+
+/*
+** Structure used internally by this VFS to record the state of an
+** open shared memory connection.
+**
+** The following fields are initialized when this object is created and
+** are read-only thereafter:
+**
+**    winShm.pShmNode
+**    winShm.id
+**
+** All other fields are read/write.  The winShm.pShmNode->mutex must be held
+** while accessing any read/write fields.
+*/
+struct winShm {
+  winShmNode *pShmNode;      /* The underlying winShmNode object */
+  winShm *pNext;             /* Next winShm with the same winShmNode */
+  u8 hasMutex;               /* True if holding the winShmNode mutex */
+  u16 sharedMask;            /* Mask of shared locks held */
+  u16 exclMask;              /* Mask of exclusive locks held */
+#ifdef SQLITE_DEBUG
+  u8 id;                     /* Id of this connection with its winShmNode */
+#endif
+};
+
+/*
+** Constants used for locking
+*/
+#define WIN_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)        /* first lock byte */
+#define WIN_SHM_DMS    (WIN_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */
+
+/*
+** Apply advisory locks for all n bytes beginning at ofst.
+*/
+#define _SHM_UNLCK  1
+#define _SHM_RDLCK  2
+#define _SHM_WRLCK  3
+static int winShmSystemLock(
+  winShmNode *pFile,    /* Apply locks to this open shared-memory segment */
+  int lockType,         /* _SHM_UNLCK, _SHM_RDLCK, or _SHM_WRLCK */
+  int ofst,             /* Offset to first byte to be locked/unlocked */
+  int nByte             /* Number of bytes to lock or unlock */
+){
+  int rc = 0;           /* Result code form Lock/UnlockFileEx() */
+
+  /* Access to the winShmNode object is serialized by the caller */
+  assert( sqlite3_mutex_held(pFile->mutex) || pFile->nRef==0 );
+
+  /* Release/Acquire the system-level lock */
+  if( lockType==_SHM_UNLCK ){
+    rc = winUnlockFile(&pFile->hFile.h, ofst, 0, nByte, 0);
+  }else{
+    /* Initialize the locking parameters */
+    DWORD dwFlags = LOCKFILE_FAIL_IMMEDIATELY;
+    if( lockType == _SHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;
+    rc = winLockFile(&pFile->hFile.h, dwFlags, ofst, 0, nByte, 0);
+  }
+  
+  if( rc!= 0 ){
+    rc = SQLITE_OK;
+  }else{
+    pFile->lastErrno =  osGetLastError();
+    rc = SQLITE_BUSY;
+  }
+
+  OSTRACE(("SHM-LOCK %d %s %s 0x%08lx\n", 
+           pFile->hFile.h,
+           rc==SQLITE_OK ? "ok" : "failed",
+           lockType==_SHM_UNLCK ? "UnlockFileEx" : "LockFileEx",
+           pFile->lastErrno));
+
+  return rc;
+}
+
+/* Forward references to VFS methods */
+static int winOpen(sqlite3_vfs*,const char*,sqlite3_file*,int,int*);
+static int winDelete(sqlite3_vfs *,const char*,int);
+
+/*
+** Purge the winShmNodeList list of all entries with winShmNode.nRef==0.
+**
+** This is not a VFS shared-memory method; it is a utility function called
+** by VFS shared-memory methods.
+*/
+static void winShmPurge(sqlite3_vfs *pVfs, int deleteFlag){
+  winShmNode **pp;
+  winShmNode *p;
+  BOOL bRc;
+  assert( winShmMutexHeld() );
+  pp = &winShmNodeList;
+  while( (p = *pp)!=0 ){
+    if( p->nRef==0 ){
+      int i;
+      if( p->mutex ) sqlite3_mutex_free(p->mutex);
+      for(i=0; i<p->nRegion; i++){
+        bRc = osUnmapViewOfFile(p->aRegion[i].pMap);
+        OSTRACE(("SHM-PURGE pid-%d unmap region=%d %s\n",
+                 (int)osGetCurrentProcessId(), i,
+                 bRc ? "ok" : "failed"));
+        bRc = osCloseHandle(p->aRegion[i].hMap);
+        OSTRACE(("SHM-PURGE pid-%d close region=%d %s\n",
+                 (int)osGetCurrentProcessId(), i,
+                 bRc ? "ok" : "failed"));
+      }
+      if( p->hFile.h != INVALID_HANDLE_VALUE ){
+        SimulateIOErrorBenign(1);
+        winClose((sqlite3_file *)&p->hFile);
+        SimulateIOErrorBenign(0);
+      }
+      if( deleteFlag ){
+        SimulateIOErrorBenign(1);
+        sqlite3BeginBenignMalloc();
+        winDelete(pVfs, p->zFilename, 0);
+        sqlite3EndBenignMalloc();
+        SimulateIOErrorBenign(0);
+      }
+      *pp = p->pNext;
+      sqlite3_free(p->aRegion);
+      sqlite3_free(p);
+    }else{
+      pp = &p->pNext;
+    }
+  }
+}
+
+/*
+** Open the shared-memory area associated with database file pDbFd.
+**
+** When opening a new shared-memory file, if no other instances of that
+** file are currently open, in this process or in other processes, then
+** the file must be truncated to zero length or have its header cleared.
+*/
+static int winOpenSharedMemory(winFile *pDbFd){
+  struct winShm *p;                  /* The connection to be opened */
+  struct winShmNode *pShmNode = 0;   /* The underlying mmapped file */
+  int rc;                            /* Result code */
+  struct winShmNode *pNew;           /* Newly allocated winShmNode */
+  int nName;                         /* Size of zName in bytes */
+
+  assert( pDbFd->pShm==0 );    /* Not previously opened */
+
+  /* Allocate space for the new sqlite3_shm object.  Also speculatively
+  ** allocate space for a new winShmNode and filename.
+  */
+  p = sqlite3_malloc( sizeof(*p) );
+  if( p==0 ) return SQLITE_IOERR_NOMEM;
+  memset(p, 0, sizeof(*p));
+  nName = sqlite3Strlen30(pDbFd->zPath);
+  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 17 );
+  if( pNew==0 ){
+    sqlite3_free(p);
+    return SQLITE_IOERR_NOMEM;
+  }
+  memset(pNew, 0, sizeof(*pNew) + nName + 17);
+  pNew->zFilename = (char*)&pNew[1];
+  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
+  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename); 
+
+  /* Look to see if there is an existing winShmNode that can be used.
+  ** If no matching winShmNode currently exists, create a new one.
+  */
+  winShmEnterMutex();
+  for(pShmNode = winShmNodeList; pShmNode; pShmNode=pShmNode->pNext){
+    /* TBD need to come up with better match here.  Perhaps
+    ** use FILE_ID_BOTH_DIR_INFO Structure.
+    */
+    if( sqlite3StrICmp(pShmNode->zFilename, pNew->zFilename)==0 ) break;
+  }
+  if( pShmNode ){
+    sqlite3_free(pNew);
+  }else{
+    pShmNode = pNew;
+    pNew = 0;
+    ((winFile*)(&pShmNode->hFile))->h = INVALID_HANDLE_VALUE;
+    pShmNode->pNext = winShmNodeList;
+    winShmNodeList = pShmNode;
+
+    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+    if( pShmNode->mutex==0 ){
+      rc = SQLITE_IOERR_NOMEM;
+      goto shm_open_err;
+    }
+
+    rc = winOpen(pDbFd->pVfs,
+                 pShmNode->zFilename,             /* Name of the file (UTF-8) */
+                 (sqlite3_file*)&pShmNode->hFile,  /* File handle here */
+                 SQLITE_OPEN_WAL | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, /* Mode flags */
+                 0);
+    if( SQLITE_OK!=rc ){
+      goto shm_open_err;
+    }
+
+    /* Check to see if another process is holding the dead-man switch.
+    ** If not, truncate the file to zero length. 
+    */
+    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
+      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);
+      if( rc!=SQLITE_OK ){
+        rc = winLogError(SQLITE_IOERR_SHMOPEN, osGetLastError(),
+                 "winOpenShm", pDbFd->zPath);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
+      rc = winShmSystemLock(pShmNode, _SHM_RDLCK, WIN_SHM_DMS, 1);
+    }
+    if( rc ) goto shm_open_err;
+  }
+
+  /* Make the new connection a child of the winShmNode */
+  p->pShmNode = pShmNode;
+#ifdef SQLITE_DEBUG
+  p->id = pShmNode->nextShmId++;
+#endif
+  pShmNode->nRef++;
+  pDbFd->pShm = p;
+  winShmLeaveMutex();
+
+  /* The reference count on pShmNode has already been incremented under
+  ** the cover of the winShmEnterMutex() mutex and the pointer from the
+  ** new (struct winShm) object to the pShmNode has been set. All that is
+  ** left to do is to link the new object into the linked list starting
+  ** at pShmNode->pFirst. This must be done while holding the pShmNode->mutex 
+  ** mutex.
+  */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  p->pNext = pShmNode->pFirst;
+  pShmNode->pFirst = p;
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return SQLITE_OK;
+
+  /* Jump here on any error */
+shm_open_err:
+  winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
+  winShmPurge(pDbFd->pVfs, 0);      /* This call frees pShmNode if required */
+  sqlite3_free(p);
+  sqlite3_free(pNew);
+  winShmLeaveMutex();
+  return rc;
+}
+
+/*
+** Close a connection to shared-memory.  Delete the underlying 
+** storage if deleteFlag is true.
+*/
+static int winShmUnmap(
+  sqlite3_file *fd,          /* Database holding shared memory */
+  int deleteFlag             /* Delete after closing if true */
+){
+  winFile *pDbFd;       /* Database holding shared-memory */
+  winShm *p;            /* The connection to be closed */
+  winShmNode *pShmNode; /* The underlying shared-memory file */
+  winShm **pp;          /* For looping over sibling connections */
+
+  pDbFd = (winFile*)fd;
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_OK;
+  pShmNode = p->pShmNode;
+
+  /* Remove connection p from the set of connections associated
+  ** with pShmNode */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
+  *pp = p->pNext;
+
+  /* Free the connection p */
+  sqlite3_free(p);
+  pDbFd->pShm = 0;
+  sqlite3_mutex_leave(pShmNode->mutex);
+
+  /* If pShmNode->nRef has reached 0, then close the underlying
+  ** shared-memory file, too */
+  winShmEnterMutex();
+  assert( pShmNode->nRef>0 );
+  pShmNode->nRef--;
+  if( pShmNode->nRef==0 ){
+    winShmPurge(pDbFd->pVfs, deleteFlag);
+  }
+  winShmLeaveMutex();
+
+  return SQLITE_OK;
+}
+
+/*
+** Change the lock state for a shared-memory segment.
+*/
+static int winShmLock(
+  sqlite3_file *fd,          /* Database file holding the shared memory */
+  int ofst,                  /* First lock to acquire or release */
+  int n,                     /* Number of locks to acquire or release */
+  int flags                  /* What to do with the lock */
+){
+  winFile *pDbFd = (winFile*)fd;        /* Connection holding shared memory */
+  winShm *p = pDbFd->pShm;              /* The shared memory being locked */
+  winShm *pX;                           /* For looping over all siblings */
+  winShmNode *pShmNode = p->pShmNode;
+  int rc = SQLITE_OK;                   /* Result code */
+  u16 mask;                             /* Mask of locks to take or release */
+
+  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
+  assert( n>=1 );
+  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
+  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );
+
+  mask = (u16)((1U<<(ofst+n)) - (1U<<ofst));
+  assert( n>1 || mask==(1<<ofst) );
+  sqlite3_mutex_enter(pShmNode->mutex);
+  if( flags & SQLITE_SHM_UNLOCK ){
+    u16 allMask = 0; /* Mask of locks held by siblings */
+
+    /* See if any siblings hold this same lock */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( pX==p ) continue;
+      assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
+      allMask |= pX->sharedMask;
+    }
+
+    /* Unlock the system-level locks */
+    if( (mask & allMask)==0 ){
+      rc = winShmSystemLock(pShmNode, _SHM_UNLCK, ofst+WIN_SHM_BASE, n);
+    }else{
+      rc = SQLITE_OK;
+    }
+
+    /* Undo the local locks */
+    if( rc==SQLITE_OK ){
+      p->exclMask &= ~mask;
+      p->sharedMask &= ~mask;
+    } 
+  }else if( flags & SQLITE_SHM_SHARED ){
+    u16 allShared = 0;  /* Union of locks held by connections other than "p" */
+
+    /* Find out which shared locks are already held by sibling connections.
+    ** If any sibling already holds an exclusive lock, go ahead and return
+    ** SQLITE_BUSY.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+      allShared |= pX->sharedMask;
+    }
+
+    /* Get shared locks at the system level, if necessary */
+    if( rc==SQLITE_OK ){
+      if( (allShared & mask)==0 ){
+        rc = winShmSystemLock(pShmNode, _SHM_RDLCK, ofst+WIN_SHM_BASE, n);
+      }else{
+        rc = SQLITE_OK;
+      }
+    }
+
+    /* Get the local shared locks */
+    if( rc==SQLITE_OK ){
+      p->sharedMask |= mask;
+    }
+  }else{
+    /* Make sure no sibling connections hold locks that will block this
+    ** lock.  If any do, return SQLITE_BUSY right away.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 || (pX->sharedMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+    }
+  
+    /* Get the exclusive locks at the system level.  Then if successful
+    ** also mark the local connection as being locked.
+    */
+    if( rc==SQLITE_OK ){
+      rc = winShmSystemLock(pShmNode, _SHM_WRLCK, ofst+WIN_SHM_BASE, n);
+      if( rc==SQLITE_OK ){
+        assert( (p->sharedMask & mask)==0 );
+        p->exclMask |= mask;
+      }
+    }
+  }
+  sqlite3_mutex_leave(pShmNode->mutex);
+  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x %s\n",
+           p->id, (int)osGetCurrentProcessId(), p->sharedMask, p->exclMask,
+           rc ? "failed" : "ok"));
+  return rc;
+}
+
+/*
+** Implement a memory barrier or memory fence on shared memory.  
+**
+** All loads and stores begun before the barrier must complete before
+** any load or store begun after the barrier.
+*/
+static void winShmBarrier(
+  sqlite3_file *fd          /* Database holding the shared memory */
+){
+  UNUSED_PARAMETER(fd);
+  /* MemoryBarrier(); // does not work -- do not know why not */
+  winShmEnterMutex();
+  winShmLeaveMutex();
+}
+
+/*
+** This function is called to obtain a pointer to region iRegion of the 
+** shared-memory associated with the database file fd. Shared-memory regions 
+** are numbered starting from zero. Each shared-memory region is szRegion 
+** bytes in size.
+**
+** If an error occurs, an error code is returned and *pp is set to NULL.
+**
+** Otherwise, if the isWrite parameter is 0 and the requested shared-memory
+** region has not been allocated (by any client, including one running in a
+** separate process), then *pp is set to NULL and SQLITE_OK returned. If 
+** isWrite is non-zero and the requested shared-memory region has not yet 
+** been allocated, it is allocated by this function.
+**
+** If the shared-memory region has already been allocated or is allocated by
+** this call as described above, then it is mapped into this processes 
+** address space (if it is not already), *pp is set to point to the mapped 
+** memory and SQLITE_OK returned.
+*/
+static int winShmMap(
+  sqlite3_file *fd,               /* Handle open on database file */
+  int iRegion,                    /* Region to retrieve */
+  int szRegion,                   /* Size of regions */
+  int isWrite,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Mapped memory */
+){
+  winFile *pDbFd = (winFile*)fd;
+  winShm *p = pDbFd->pShm;
+  winShmNode *pShmNode;
+  int rc = SQLITE_OK;
+
+  if( !p ){
+    rc = winOpenSharedMemory(pDbFd);
+    if( rc!=SQLITE_OK ) return rc;
+    p = pDbFd->pShm;
+  }
+  pShmNode = p->pShmNode;
+
+  sqlite3_mutex_enter(pShmNode->mutex);
+  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
+
+  if( pShmNode->nRegion<=iRegion ){
+    struct ShmRegion *apNew;           /* New aRegion[] array */
+    int nByte = (iRegion+1)*szRegion;  /* Minimum required file size */
+    sqlite3_int64 sz;                  /* Current size of wal-index file */
+
+    pShmNode->szRegion = szRegion;
+
+    /* The requested region is not mapped into this processes address space.
+    ** Check to see if it has been allocated (i.e. if the wal-index file is
+    ** large enough to contain the requested region).
+    */
+    rc = winFileSize((sqlite3_file *)&pShmNode->hFile, &sz);
+    if( rc!=SQLITE_OK ){
+      rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
+               "winShmMap1", pDbFd->zPath);
+      goto shmpage_out;
+    }
+
+    if( sz<nByte ){
+      /* The requested memory region does not exist. If isWrite is set to
+      ** zero, exit early. *pp will be set to NULL and SQLITE_OK returned.
+      **
+      ** Alternatively, if isWrite is non-zero, use ftruncate() to allocate
+      ** the requested memory region.
+      */
+      if( !isWrite ) goto shmpage_out;
+      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, nByte);
+      if( rc!=SQLITE_OK ){
+        rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
+                 "winShmMap2", pDbFd->zPath);
+        goto shmpage_out;
+      }
+    }
+
+    /* Map the requested memory region into this processes address space. */
+    apNew = (struct ShmRegion *)sqlite3_realloc(
+        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
+    );
+    if( !apNew ){
+      rc = SQLITE_IOERR_NOMEM;
+      goto shmpage_out;
+    }
+    pShmNode->aRegion = apNew;
+
+    while( pShmNode->nRegion<=iRegion ){
+      HANDLE hMap;                /* file-mapping handle */
+      void *pMap = 0;             /* Mapped memory region */
+     
+#if SQLITE_OS_WINRT
+      hMap = osCreateFileMappingFromApp(pShmNode->hFile.h,
+          NULL, PAGE_READWRITE, nByte, NULL
+      );
+#else
+      hMap = osCreateFileMappingW(pShmNode->hFile.h, 
+          NULL, PAGE_READWRITE, 0, nByte, NULL
+      );
+#endif
+      OSTRACE(("SHM-MAP pid-%d create region=%d nbyte=%d %s\n",
+               (int)osGetCurrentProcessId(), pShmNode->nRegion, nByte,
+               hMap ? "ok" : "failed"));
+      if( hMap ){
+        int iOffset = pShmNode->nRegion*szRegion;
+        int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
+#if SQLITE_OS_WINRT
+        pMap = osMapViewOfFileFromApp(hMap, FILE_MAP_WRITE | FILE_MAP_READ,
+            iOffset - iOffsetShift, szRegion + iOffsetShift
+        );
+#else
+        pMap = osMapViewOfFile(hMap, FILE_MAP_WRITE | FILE_MAP_READ,
+            0, iOffset - iOffsetShift, szRegion + iOffsetShift
+        );
+#endif
+        OSTRACE(("SHM-MAP pid-%d map region=%d offset=%d size=%d %s\n",
+                 (int)osGetCurrentProcessId(), pShmNode->nRegion, iOffset,
+                 szRegion, pMap ? "ok" : "failed"));
+      }
+      if( !pMap ){
+        pShmNode->lastErrno = osGetLastError();
+        rc = winLogError(SQLITE_IOERR_SHMMAP, pShmNode->lastErrno,
+                 "winShmMap3", pDbFd->zPath);
+        if( hMap ) osCloseHandle(hMap);
+        goto shmpage_out;
+      }
+
+      pShmNode->aRegion[pShmNode->nRegion].pMap = pMap;
+      pShmNode->aRegion[pShmNode->nRegion].hMap = hMap;
+      pShmNode->nRegion++;
+    }
+  }
+
+shmpage_out:
+  if( pShmNode->nRegion>iRegion ){
+    int iOffset = iRegion*szRegion;
+    int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
+    char *p = (char *)pShmNode->aRegion[iRegion].pMap;
+    *pp = (void *)&p[iOffsetShift];
+  }else{
+    *pp = 0;
+  }
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return rc;
+}
+
+#else
+# define winShmMap     0
+# define winShmLock    0
+# define winShmBarrier 0
+# define winShmUnmap   0
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+/*
+** Here ends the implementation of all sqlite3_file methods.
+**
+********************** End sqlite3_file Methods *******************************
+******************************************************************************/
+
 /*
 ** This vector defines all the methods that can operate on an
 ** sqlite3_file for win32.
 */
 static const sqlite3_io_methods winIoMethod = {
-  1,                        /* iVersion */
-  winClose,
-  winRead,
-  winWrite,
-  winTruncate,
-  winSync,
-  winFileSize,
-  winLock,
-  winUnlock,
-  winCheckReservedLock,
-  winFileControl,
-  winSectorSize,
-  winDeviceCharacteristics
+  2,                              /* iVersion */
+  winClose,                       /* xClose */
+  winRead,                        /* xRead */
+  winWrite,                       /* xWrite */
+  winTruncate,                    /* xTruncate */
+  winSync,                        /* xSync */
+  winFileSize,                    /* xFileSize */
+  winLock,                        /* xLock */
+  winUnlock,                      /* xUnlock */
+  winCheckReservedLock,           /* xCheckReservedLock */
+  winFileControl,                 /* xFileControl */
+  winSectorSize,                  /* xSectorSize */
+  winDeviceCharacteristics,       /* xDeviceCharacteristics */
+  winShmMap,                      /* xShmMap */
+  winShmLock,                     /* xShmLock */
+  winShmBarrier,                  /* xShmBarrier */
+  winShmUnmap                     /* xShmUnmap */
 };
 
-/***************************************************************************
-** Here ends the I/O methods that form the sqlite3_io_methods object.
+/****************************************************************************
+**************************** sqlite3_vfs methods ****************************
 **
-** The next block of code implements the VFS methods.
-****************************************************************************/
+** This division contains the implementation of methods on the
+** sqlite3_vfs object.
+*/
 
 /*
 ** Convert a UTF-8 filename into whatever form the underlying
@@ -28167,13 +33257,12 @@ static void *convertUtf8Filename(const char *zFilename){
   void *zConverted = 0;
   if( isNT() ){
     zConverted = utf8ToUnicode(zFilename);
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
-    zConverted = utf8ToMbcs(zFilename);
-#endif
   }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    zConverted = sqlite3_win32_utf8_to_mbcs(zFilename);
+  }
+#endif
   /* caller will handle out of memory */
   return zConverted;
 }
@@ -28188,83 +33277,105 @@ static int getTempname(int nBuf, char *zBuf){
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "0123456789";
   size_t i, j;
-  char zTempPath[MAX_PATH+1];
+  int nTempPath;
+  char zTempPath[MAX_PATH+2];
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing. 
+  */
+  SimulateIOError( return SQLITE_IOERR );
+
+  memset(zTempPath, 0, MAX_PATH+2);
+
   if( sqlite3_temp_directory ){
     sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", sqlite3_temp_directory);
-  }else if( isNT() ){
+  }
+#if !SQLITE_OS_WINRT
+  else if( isNT() ){
     char *zMulti;
     WCHAR zWidePath[MAX_PATH];
-    GetTempPathW(MAX_PATH-30, zWidePath);
+    osGetTempPathW(MAX_PATH-30, zWidePath);
     zMulti = unicodeToUtf8(zWidePath);
     if( zMulti ){
       sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zMulti);
-      free(zMulti);
+      sqlite3_free(zMulti);
     }else{
-      return SQLITE_NOMEM;
+      return SQLITE_IOERR_NOMEM;
     }
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-** Since the ASCII version of these Windows API do not exist for WINCE,
-** it's important to not reference them for WINCE builds.
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
     char *zUtf8;
     char zMbcsPath[MAX_PATH];
-    GetTempPathA(MAX_PATH-30, zMbcsPath);
+    osGetTempPathA(MAX_PATH-30, zMbcsPath);
     zUtf8 = sqlite3_win32_mbcs_to_utf8(zMbcsPath);
     if( zUtf8 ){
       sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zUtf8);
-      free(zUtf8);
+      sqlite3_free(zUtf8);
     }else{
-      return SQLITE_NOMEM;
+      return SQLITE_IOERR_NOMEM;
     }
-#endif
   }
-  for(i=sqlite3Strlen30(zTempPath); i>0 && zTempPath[i-1]=='\\'; i--){}
+#endif
+#endif
+
+  /* Check that the output buffer is large enough for the temporary file 
+  ** name. If it is not, return SQLITE_ERROR.
+  */
+  nTempPath = sqlite3Strlen30(zTempPath);
+
+  if( (nTempPath + sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX) + 18) >= nBuf ){
+    return SQLITE_ERROR;
+  }
+
+  for(i=nTempPath; i>0 && zTempPath[i-1]=='\\'; i--){}
   zTempPath[i] = 0;
-  sqlite3_snprintf(nBuf-30, zBuf,
-                   "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
+
+  sqlite3_snprintf(nBuf-18, zBuf, (nTempPath > 0) ?
+                       "%s\\"SQLITE_TEMP_FILE_PREFIX : SQLITE_TEMP_FILE_PREFIX,
+                   zTempPath);
   j = sqlite3Strlen30(zBuf);
-  sqlite3_randomness(20, &zBuf[j]);
-  for(i=0; i<20; i++, j++){
+  sqlite3_randomness(15, &zBuf[j]);
+  for(i=0; i<15; i++, j++){
     zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
   }
   zBuf[j] = 0;
-  OSTRACE2("TEMP FILENAME: %s\n", zBuf);
+  zBuf[j+1] = 0;
+
+  OSTRACE(("TEMP FILENAME: %s\n", zBuf));
   return SQLITE_OK; 
 }
 
 /*
-** The return value of getLastErrorMsg
-** is zero if the error message fits in the buffer, or non-zero
-** otherwise (if the message was truncated).
+** Return TRUE if the named file is really a directory.  Return false if
+** it is something other than a directory, or if there is any kind of memory
+** allocation failure.
 */
-static int getLastErrorMsg(int nBuf, char *zBuf){
-  DWORD error = GetLastError();
+static int winIsDir(const void *zConverted){
+  DWORD attr;
+  int rc = 0;
+  DWORD lastErrno;
 
-#if SQLITE_OS_WINCE
-  sqlite3_snprintf(nBuf, zBuf, "OsError 0x%x (%u)", error, error);
-#else
-  /* FormatMessage returns 0 on failure.  Otherwise it
-  ** returns the number of TCHARs written to the output
-  ** buffer, excluding the terminating null char.
-  */
-  if (!FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM,
-                      NULL,
-                      error,
-                      0,
-                      zBuf,
-                      nBuf-1,
-                      0))
-  {
-    sqlite3_snprintf(nBuf, zBuf, "OsError 0x%x (%u)", error, error);
-  }
+  if( isNT() ){
+    int cnt = 0;
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
+                             GetFileExInfoStandard,
+                             &sAttrData)) && retryIoerr(&cnt, &lastErrno) ){}
+    if( !rc ){
+      return 0; /* Invalid name? */
+    }
+    attr = sAttrData.dwFileAttributes;
+#if SQLITE_OS_WINCE==0
+  }else{
+    attr = osGetFileAttributesA((char*)zConverted);
 #endif
-
-  return 0;
+  }
+  return (attr!=INVALID_FILE_ATTRIBUTES) && (attr&FILE_ATTRIBUTE_DIRECTORY);
 }
 
-
 /*
 ** Open a file.
 */
@@ -28276,6 +33387,7 @@ static int winOpen(
   int *pOutFlags            /* Status return flags */
 ){
   HANDLE h;
+  DWORD lastErrno;
   DWORD dwDesiredAccess;
   DWORD dwShareMode;
   DWORD dwCreationDisposition;
@@ -28284,45 +33396,129 @@ static int winOpen(
   int isTemp = 0;
 #endif
   winFile *pFile = (winFile*)id;
-  void *zConverted;                 /* Filename in OS encoding */
-  const char *zUtf8Name = zName;    /* Filename in UTF-8 encoding */
-  char zTmpname[MAX_PATH+1];        /* Buffer used to create temp filename */
+  void *zConverted;              /* Filename in OS encoding */
+  const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
+  int cnt = 0;
 
+  /* If argument zPath is a NULL pointer, this function is required to open
+  ** a temporary file. Use this buffer to store the file name in.
+  */
+  char zTmpname[MAX_PATH+2];     /* Buffer used to create temp filename */
+
+  int rc = SQLITE_OK;            /* Function Return Code */
+#if !defined(NDEBUG) || SQLITE_OS_WINCE
+  int eType = flags&0xFFFFFF00;  /* Type of file to open */
+#endif
+
+  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
+  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
+  int isCreate     = (flags & SQLITE_OPEN_CREATE);
+#ifndef NDEBUG
+  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
+#endif
+  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
+
+#ifndef NDEBUG
+  int isOpenJournal = (isCreate && (
+        eType==SQLITE_OPEN_MASTER_JOURNAL 
+     || eType==SQLITE_OPEN_MAIN_JOURNAL 
+     || eType==SQLITE_OPEN_WAL
+  ));
+#endif
+
+  /* Check the following statements are true: 
+  **
+  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and 
+  **   (b) if CREATE is set, then READWRITE must also be set, and
+  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
+  **   (d) if DELETEONCLOSE is set, then CREATE must also be set.
+  */
+  assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
+  assert(isCreate==0 || isReadWrite);
+  assert(isExclusive==0 || isCreate);
+  assert(isDelete==0 || isCreate);
+
+  /* The main DB, main journal, WAL file and master journal are never 
+  ** automatically deleted. Nor are they ever temporary files.  */
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MASTER_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL );
+
+  /* Assert that the upper layer has set one of the "file-type" flags. */
+  assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB 
+       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL 
+       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_MASTER_JOURNAL 
+       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
+  );
+
+  assert( id!=0 );
   UNUSED_PARAMETER(pVfs);
 
+#if SQLITE_OS_WINRT
+  if( !sqlite3_temp_directory ){
+    sqlite3_log(SQLITE_ERROR,
+        "sqlite3_temp_directory variable should be set for WinRT");
+  }
+#endif
+
+  pFile->h = INVALID_HANDLE_VALUE;
+
   /* If the second argument to this function is NULL, generate a 
   ** temporary file name to use 
   */
   if( !zUtf8Name ){
-    int rc = getTempname(MAX_PATH+1, zTmpname);
+    assert(isDelete && !isOpenJournal);
+    rc = getTempname(MAX_PATH+2, zTmpname);
     if( rc!=SQLITE_OK ){
       return rc;
     }
     zUtf8Name = zTmpname;
   }
 
+  /* Database filenames are double-zero terminated if they are not
+  ** URIs with parameters.  Hence, they can always be passed into
+  ** sqlite3_uri_parameter().
+  */
+  assert( (eType!=SQLITE_OPEN_MAIN_DB) || (flags & SQLITE_OPEN_URI) ||
+        zUtf8Name[strlen(zUtf8Name)+1]==0 );
+
   /* Convert the filename to the system encoding. */
   zConverted = convertUtf8Filename(zUtf8Name);
   if( zConverted==0 ){
-    return SQLITE_NOMEM;
+    return SQLITE_IOERR_NOMEM;
   }
 
-  if( flags & SQLITE_OPEN_READWRITE ){
+  if( winIsDir(zConverted) ){
+    sqlite3_free(zConverted);
+    return SQLITE_CANTOPEN_ISDIR;
+  }
+
+  if( isReadWrite ){
     dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
   }else{
     dwDesiredAccess = GENERIC_READ;
   }
-  if( flags & SQLITE_OPEN_CREATE ){
+
+  /* SQLITE_OPEN_EXCLUSIVE is used to make sure that a new file is 
+  ** created. SQLite doesn't use it to indicate "exclusive access" 
+  ** as it is usually understood.
+  */
+  if( isExclusive ){
+    /* Creates a new file, only if it does not already exist. */
+    /* If the file exists, it fails. */
+    dwCreationDisposition = CREATE_NEW;
+  }else if( isCreate ){
+    /* Open existing file, or create if it doesn't exist */
     dwCreationDisposition = OPEN_ALWAYS;
   }else{
+    /* Opens a file, only if it exists. */
     dwCreationDisposition = OPEN_EXISTING;
   }
-  if( flags & SQLITE_OPEN_MAIN_DB ){
-    dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
-  }else{
-    dwShareMode = 0;
-  }
-  if( flags & SQLITE_OPEN_DELETEONCLOSE ){
+
+  dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
+
+  if( isDelete ){
 #if SQLITE_OS_WINCE
     dwFlagsAndAttributes = FILE_ATTRIBUTE_HIDDEN;
     isTemp = 1;
@@ -28339,74 +33535,113 @@ static int winOpen(
 #if SQLITE_OS_WINCE
   dwFlagsAndAttributes |= FILE_FLAG_RANDOM_ACCESS;
 #endif
+
   if( isNT() ){
-    h = CreateFileW((WCHAR*)zConverted,
-       dwDesiredAccess,
-       dwShareMode,
-       NULL,
-       dwCreationDisposition,
-       dwFlagsAndAttributes,
-       NULL
-    );
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-** Since the ASCII version of these Windows API do not exist for WINCE,
-** it's important to not reference them for WINCE builds.
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
-    h = CreateFileA((char*)zConverted,
-       dwDesiredAccess,
-       dwShareMode,
-       NULL,
-       dwCreationDisposition,
-       dwFlagsAndAttributes,
-       NULL
-    );
+#if SQLITE_OS_WINRT
+    CREATEFILE2_EXTENDED_PARAMETERS extendedParameters;
+    extendedParameters.dwSize = sizeof(CREATEFILE2_EXTENDED_PARAMETERS);
+    extendedParameters.dwFileAttributes =
+            dwFlagsAndAttributes & FILE_ATTRIBUTE_MASK;
+    extendedParameters.dwFileFlags = dwFlagsAndAttributes & FILE_FLAG_MASK;
+    extendedParameters.dwSecurityQosFlags = SECURITY_ANONYMOUS;
+    extendedParameters.lpSecurityAttributes = NULL;
+    extendedParameters.hTemplateFile = NULL;
+    while( (h = osCreateFile2((LPCWSTR)zConverted,
+                              dwDesiredAccess,
+                              dwShareMode,
+                              dwCreationDisposition,
+                              &extendedParameters))==INVALID_HANDLE_VALUE &&
+                              retryIoerr(&cnt, &lastErrno) ){
+               /* Noop */
+    }
+#else
+    while( (h = osCreateFileW((LPCWSTR)zConverted,
+                              dwDesiredAccess,
+                              dwShareMode, NULL,
+                              dwCreationDisposition,
+                              dwFlagsAndAttributes,
+                              NULL))==INVALID_HANDLE_VALUE &&
+                              retryIoerr(&cnt, &lastErrno) ){
+               /* Noop */
+    }
 #endif
   }
-  if( h==INVALID_HANDLE_VALUE ){
-    free(zConverted);
-    if( flags & SQLITE_OPEN_READWRITE ){
-      return winOpen(0, zName, id, 
-             ((flags|SQLITE_OPEN_READONLY)&~SQLITE_OPEN_READWRITE), pOutFlags);
-    }else{
-      return SQLITE_CANTOPEN;
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    while( (h = osCreateFileA((LPCSTR)zConverted,
+                              dwDesiredAccess,
+                              dwShareMode, NULL,
+                              dwCreationDisposition,
+                              dwFlagsAndAttributes,
+                              NULL))==INVALID_HANDLE_VALUE &&
+                              retryIoerr(&cnt, &lastErrno) ){
+               /* Noop */
     }
   }
+#endif
+  logIoerr(cnt);
+
+  OSTRACE(("OPEN %d %s 0x%lx %s\n", 
+           h, zName, dwDesiredAccess, 
+           h==INVALID_HANDLE_VALUE ? "failed" : "ok"));
+
+  if( h==INVALID_HANDLE_VALUE ){
+    pFile->lastErrno = lastErrno;
+    winLogError(SQLITE_CANTOPEN, pFile->lastErrno, "winOpen", zUtf8Name);
+    sqlite3_free(zConverted);
+    if( isReadWrite && !isExclusive ){
+      return winOpen(pVfs, zName, id, 
+             ((flags|SQLITE_OPEN_READONLY)&~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE)), pOutFlags);
+    }else{
+      return SQLITE_CANTOPEN_BKPT;
+    }
+  }
+
   if( pOutFlags ){
-    if( flags & SQLITE_OPEN_READWRITE ){
+    if( isReadWrite ){
       *pOutFlags = SQLITE_OPEN_READWRITE;
     }else{
       *pOutFlags = SQLITE_OPEN_READONLY;
     }
   }
+
   memset(pFile, 0, sizeof(*pFile));
   pFile->pMethod = &winIoMethod;
   pFile->h = h;
+  pFile->lastErrno = NO_ERROR;
+  pFile->pVfs = pVfs;
+#ifndef SQLITE_OMIT_WAL
+  pFile->pShm = 0;
+#endif
+  pFile->zPath = zName;
+  if( sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
+    pFile->ctrlFlags |= WINFILE_PSOW;
+  }
+
 #if SQLITE_OS_WINCE
-  if( (flags & (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)) ==
-               (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)
+  if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB
        && !winceCreateLock(zName, pFile)
   ){
-    CloseHandle(h);
-    free(zConverted);
-    return SQLITE_CANTOPEN;
+    osCloseHandle(h);
+    sqlite3_free(zConverted);
+    return SQLITE_CANTOPEN_BKPT;
   }
   if( isTemp ){
     pFile->zDeleteOnClose = zConverted;
   }else
 #endif
   {
-    free(zConverted);
+    sqlite3_free(zConverted);
   }
+
   OpenCounter(+1);
-  return SQLITE_OK;
+  return rc;
 }
 
 /*
 ** Delete the named file.
 **
-** Note that windows does not allow a file to be deleted if some other
+** Note that Windows does not allow a file to be deleted if some other
 ** process has it open.  Sometimes a virus scanner or indexing program
 ** will open a journal file shortly after it is created in order to do
 ** whatever it does.  While this other process is holding the
@@ -28415,47 +33650,89 @@ static int winOpen(
 ** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
 ** up and returning an error.
 */
-#define MX_DELETION_ATTEMPTS 5
 static int winDelete(
   sqlite3_vfs *pVfs,          /* Not used on win32 */
   const char *zFilename,      /* Name of file to delete */
   int syncDir                 /* Not used on win32 */
 ){
   int cnt = 0;
-  DWORD rc;
-  DWORD error = 0;
-  void *zConverted = convertUtf8Filename(zFilename);
+  int rc;
+  DWORD attr;
+  DWORD lastErrno;
+  void *zConverted;
   UNUSED_PARAMETER(pVfs);
   UNUSED_PARAMETER(syncDir);
-  if( zConverted==0 ){
-    return SQLITE_NOMEM;
-  }
+
   SimulateIOError(return SQLITE_IOERR_DELETE);
-  if( isNT() ){
-    do{
-      DeleteFileW(zConverted);
-    }while(   (   ((rc = GetFileAttributesW(zConverted)) != INVALID_FILE_ATTRIBUTES)
-               || ((error = GetLastError()) == ERROR_ACCESS_DENIED))
-           && (++cnt < MX_DELETION_ATTEMPTS)
-           && (Sleep(100), 1) );
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-** Since the ASCII version of these Windows API do not exist for WINCE,
-** it's important to not reference them for WINCE builds.
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
-    do{
-      DeleteFileA(zConverted);
-    }while(   (   ((rc = GetFileAttributesA(zConverted)) != INVALID_FILE_ATTRIBUTES)
-               || ((error = GetLastError()) == ERROR_ACCESS_DENIED))
-           && (++cnt < MX_DELETION_ATTEMPTS)
-           && (Sleep(100), 1) );
-#endif
+  zConverted = convertUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    return SQLITE_IOERR_NOMEM;
   }
-  free(zConverted);
-  OSTRACE2("DELETE \"%s\"\n", zFilename);
-  return (   (rc == INVALID_FILE_ATTRIBUTES) 
-          && (error == ERROR_FILE_NOT_FOUND)) ? SQLITE_OK : SQLITE_IOERR_DELETE;
+  if( isNT() ){
+    do {
+#if SQLITE_OS_WINRT
+      WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+      memset(&sAttrData, 0, sizeof(sAttrData));
+      if ( osGetFileAttributesExW(zConverted, GetFileExInfoStandard,
+                                  &sAttrData) ){
+        attr = sAttrData.dwFileAttributes;
+      }else{
+        rc = SQLITE_OK; /* Already gone? */
+        break;
+      }
+#else
+      attr = osGetFileAttributesW(zConverted);
+#endif
+      if ( attr==INVALID_FILE_ATTRIBUTES ){
+        rc = SQLITE_OK; /* Already gone? */
+        break;
+      }
+      if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
+        rc = SQLITE_ERROR; /* Files only. */
+        break;
+      }
+      if ( osDeleteFileW(zConverted) ){
+        rc = SQLITE_OK; /* Deleted OK. */
+        break;
+      }
+      if ( !retryIoerr(&cnt, &lastErrno) ){
+        rc = SQLITE_ERROR; /* No more retries. */
+        break;
+      }
+    } while(1);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    do {
+      attr = osGetFileAttributesA(zConverted);
+      if ( attr==INVALID_FILE_ATTRIBUTES ){
+        rc = SQLITE_OK; /* Already gone? */
+        break;
+      }
+      if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
+        rc = SQLITE_ERROR; /* Files only. */
+        break;
+      }
+      if ( osDeleteFileA(zConverted) ){
+        rc = SQLITE_OK; /* Deleted OK. */
+        break;
+      }
+      if ( !retryIoerr(&cnt, &lastErrno) ){
+        rc = SQLITE_ERROR; /* No more retries. */
+        break;
+      }
+    } while(1);
+  }
+#endif
+  if( rc ){
+    rc = winLogError(SQLITE_IOERR_DELETE, lastErrno,
+             "winDelete", zFilename);
+  }else{
+    logIoerr(cnt);
+  }
+  sqlite3_free(zConverted);
+  OSTRACE(("DELETE \"%s\" %s\n", zFilename, (rc ? "failed" : "ok" )));
+  return rc;
 }
 
 /*
@@ -28469,30 +33746,58 @@ static int winAccess(
 ){
   DWORD attr;
   int rc = 0;
-  void *zConverted = convertUtf8Filename(zFilename);
+  DWORD lastErrno;
+  void *zConverted;
   UNUSED_PARAMETER(pVfs);
+
+  SimulateIOError( return SQLITE_IOERR_ACCESS; );
+  zConverted = convertUtf8Filename(zFilename);
   if( zConverted==0 ){
-    return SQLITE_NOMEM;
+    return SQLITE_IOERR_NOMEM;
   }
   if( isNT() ){
-    attr = GetFileAttributesW((WCHAR*)zConverted);
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-** Since the ASCII version of these Windows API do not exist for WINCE,
-** it's important to not reference them for WINCE builds.
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
-    attr = GetFileAttributesA((char*)zConverted);
-#endif
+    int cnt = 0;
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
+                             GetFileExInfoStandard, 
+                             &sAttrData)) && retryIoerr(&cnt, &lastErrno) ){}
+    if( rc ){
+      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
+      ** as if it does not exist.
+      */
+      if(    flags==SQLITE_ACCESS_EXISTS
+          && sAttrData.nFileSizeHigh==0 
+          && sAttrData.nFileSizeLow==0 ){
+        attr = INVALID_FILE_ATTRIBUTES;
+      }else{
+        attr = sAttrData.dwFileAttributes;
+      }
+    }else{
+      logIoerr(cnt);
+      if( lastErrno!=ERROR_FILE_NOT_FOUND && lastErrno!=ERROR_PATH_NOT_FOUND ){
+        winLogError(SQLITE_IOERR_ACCESS, lastErrno, "winAccess", zFilename);
+        sqlite3_free(zConverted);
+        return SQLITE_IOERR_ACCESS;
+      }else{
+        attr = INVALID_FILE_ATTRIBUTES;
+      }
+    }
   }
-  free(zConverted);
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    attr = osGetFileAttributesA((char*)zConverted);
+  }
+#endif
+  sqlite3_free(zConverted);
   switch( flags ){
     case SQLITE_ACCESS_READ:
     case SQLITE_ACCESS_EXISTS:
       rc = attr!=INVALID_FILE_ATTRIBUTES;
       break;
     case SQLITE_ACCESS_READWRITE:
-      rc = (attr & FILE_ATTRIBUTE_READONLY)==0;
+      rc = attr!=INVALID_FILE_ATTRIBUTES &&
+             (attr & FILE_ATTRIBUTE_READONLY)==0;
       break;
     default:
       assert(!"Invalid flags argument");
@@ -28502,6 +33807,43 @@ static int winAccess(
 }
 
 
+/*
+** Returns non-zero if the specified path name should be used verbatim.  If
+** non-zero is returned from this function, the calling function must simply
+** use the provided path name verbatim -OR- resolve it into a full path name
+** using the GetFullPathName Win32 API function (if available).
+*/
+static BOOL winIsVerbatimPathname(
+  const char *zPathname
+){
+  /*
+  ** If the path name starts with a forward slash or a backslash, it is either
+  ** a legal UNC name, a volume relative path, or an absolute path name in the
+  ** "Unix" format on Windows.  There is no easy way to differentiate between
+  ** the final two cases; therefore, we return the safer return value of TRUE
+  ** so that callers of this function will simply use it verbatim.
+  */
+  if ( zPathname[0]=='/' || zPathname[0]=='\\' ){
+    return TRUE;
+  }
+
+  /*
+  ** If the path name starts with a letter and a colon it is either a volume
+  ** relative path or an absolute path.  Callers of this function must not
+  ** attempt to treat it as a relative path name (i.e. they should simply use
+  ** it verbatim).
+  */
+  if ( sqlite3Isalpha(zPathname[0]) && zPathname[1]==':' ){
+    return TRUE;
+  }
+
+  /*
+  ** If we get to this point, the path name should almost certainly be a purely
+  ** relative one (i.e. not a UNC name, not absolute, and not volume relative).
+  */
+  return FALSE;
+}
+
 /*
 ** Turn a relative pathname into a full pathname.  Write the full
 ** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
@@ -28515,61 +33857,119 @@ static int winFullPathname(
 ){
   
 #if defined(__CYGWIN__)
+  SimulateIOError( return SQLITE_ERROR );
   UNUSED_PARAMETER(nFull);
-  cygwin_conv_to_full_win32_path(zRelative, zFull);
+  assert( pVfs->mxPathname>=MAX_PATH );
+  assert( nFull>=pVfs->mxPathname );
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a slash.
+    */
+    char zOut[MAX_PATH+1];
+    memset(zOut, 0, MAX_PATH+1);
+    cygwin_conv_to_win32_path(zRelative, zOut); /* POSIX to Win32 */
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s\\%s",
+                     sqlite3_data_directory, zOut);
+  }else{
+    /*
+    ** NOTE: The Cygwin docs state that the maximum length needed
+    **       for the buffer passed to cygwin_conv_to_full_win32_path
+    **       is MAX_PATH.
+    */
+    cygwin_conv_to_full_win32_path(zRelative, zFull);
+  }
   return SQLITE_OK;
 #endif
 
-#if SQLITE_OS_WINCE
-  UNUSED_PARAMETER(nFull);
+#if (SQLITE_OS_WINCE || SQLITE_OS_WINRT) && !defined(__CYGWIN__)
+  SimulateIOError( return SQLITE_ERROR );
   /* WinCE has no concept of a relative pathname, or so I am told. */
-  sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zRelative);
+  /* WinRT has no way to convert a relative path to an absolute one. */
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a backslash.
+    */
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s\\%s",
+                     sqlite3_data_directory, zRelative);
+  }else{
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zRelative);
+  }
   return SQLITE_OK;
 #endif
 
-#if !SQLITE_OS_WINCE && !defined(__CYGWIN__)
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(__CYGWIN__)
   int nByte;
   void *zConverted;
   char *zOut;
-  UNUSED_PARAMETER(nFull);
-  zConverted = convertUtf8Filename(zRelative);
-  if( isNT() ){
-    WCHAR *zTemp;
-    nByte = GetFullPathNameW((WCHAR*)zConverted, 0, 0, 0) + 3;
-    zTemp = malloc( nByte*sizeof(zTemp[0]) );
-    if( zTemp==0 ){
-      free(zConverted);
-      return SQLITE_NOMEM;
-    }
-    GetFullPathNameW((WCHAR*)zConverted, nByte, zTemp, 0);
-    free(zConverted);
-    zOut = unicodeToUtf8(zTemp);
-    free(zTemp);
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-** Since the ASCII version of these Windows API do not exist for WINCE,
-** it's important to not reference them for WINCE builds.
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
-    char *zTemp;
-    nByte = GetFullPathNameA((char*)zConverted, 0, 0, 0) + 3;
-    zTemp = malloc( nByte*sizeof(zTemp[0]) );
-    if( zTemp==0 ){
-      free(zConverted);
-      return SQLITE_NOMEM;
-    }
-    GetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
-    free(zConverted);
-    zOut = sqlite3_win32_mbcs_to_utf8(zTemp);
-    free(zTemp);
-#endif
+
+  /* If this path name begins with "/X:", where "X" is any alphabetic
+  ** character, discard the initial "/" from the pathname.
+  */
+  if( zRelative[0]=='/' && sqlite3Isalpha(zRelative[1]) && zRelative[2]==':' ){
+    zRelative++;
   }
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing. This function could fail if, for example, the
+  ** current working directory has been unlinked.
+  */
+  SimulateIOError( return SQLITE_ERROR );
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a backslash.
+    */
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s\\%s",
+                     sqlite3_data_directory, zRelative);
+    return SQLITE_OK;
+  }
+  zConverted = convertUtf8Filename(zRelative);
+  if( zConverted==0 ){
+    return SQLITE_IOERR_NOMEM;
+  }
+  if( isNT() ){
+    LPWSTR zTemp;
+    nByte = osGetFullPathNameW((LPCWSTR)zConverted, 0, 0, 0) + 3;
+    zTemp = sqlite3_malloc( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      sqlite3_free(zConverted);
+      return SQLITE_IOERR_NOMEM;
+    }
+    osGetFullPathNameW((LPCWSTR)zConverted, nByte, zTemp, 0);
+    sqlite3_free(zConverted);
+    zOut = unicodeToUtf8(zTemp);
+    sqlite3_free(zTemp);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zTemp;
+    nByte = osGetFullPathNameA((char*)zConverted, 0, 0, 0) + 3;
+    zTemp = sqlite3_malloc( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      sqlite3_free(zConverted);
+      return SQLITE_IOERR_NOMEM;
+    }
+    osGetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
+    sqlite3_free(zConverted);
+    zOut = sqlite3_win32_mbcs_to_utf8(zTemp);
+    sqlite3_free(zTemp);
+  }
+#endif
   if( zOut ){
-    sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zOut);
-    free(zOut);
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zOut);
+    sqlite3_free(zOut);
     return SQLITE_OK;
   }else{
-    return SQLITE_NOMEM;
+    return SQLITE_IOERR_NOMEM;
   }
 #endif
 }
@@ -28591,37 +33991,31 @@ static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
     return 0;
   }
   if( isNT() ){
-    h = LoadLibraryW((WCHAR*)zConverted);
-/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
-** Since the ASCII version of these Windows API do not exist for WINCE,
-** it's important to not reference them for WINCE builds.
-*/
-#if SQLITE_OS_WINCE==0
-  }else{
-    h = LoadLibraryA((char*)zConverted);
+#if SQLITE_OS_WINRT
+    h = osLoadPackagedLibrary((LPCWSTR)zConverted, 0);
+#else
+    h = osLoadLibraryW((LPCWSTR)zConverted);
 #endif
   }
-  free(zConverted);
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    h = osLoadLibraryA((char*)zConverted);
+  }
+#endif
+  sqlite3_free(zConverted);
   return (void*)h;
 }
 static void winDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
   UNUSED_PARAMETER(pVfs);
-  getLastErrorMsg(nBuf, zBufOut);
+  getLastErrorMsg(osGetLastError(), nBuf, zBufOut);
 }
-void (*winDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol))(void){
+static void (*winDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol))(void){
   UNUSED_PARAMETER(pVfs);
-#if SQLITE_OS_WINCE
-  /* The GetProcAddressA() routine is only available on wince. */
-  return (void(*)(void))GetProcAddressA((HANDLE)pHandle, zSymbol);
-#else
-  /* All other windows platforms expect GetProcAddress() to take
-  ** an Ansi string regardless of the _UNICODE setting */
-  return (void(*)(void))GetProcAddress((HANDLE)pHandle, zSymbol);
-#endif
+  return (void(*)(void))osGetProcAddressA((HANDLE)pHandle, zSymbol);
 }
-void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
+static void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
   UNUSED_PARAMETER(pVfs);
-  FreeLibrary((HANDLE)pHandle);
+  osFreeLibrary((HANDLE)pHandle);
 }
 #else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
   #define winDlOpen  0
@@ -28643,23 +34037,31 @@ static int winRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
 #else
   if( sizeof(SYSTEMTIME)<=nBuf-n ){
     SYSTEMTIME x;
-    GetSystemTime(&x);
+    osGetSystemTime(&x);
     memcpy(&zBuf[n], &x, sizeof(x));
     n += sizeof(x);
   }
   if( sizeof(DWORD)<=nBuf-n ){
-    DWORD pid = GetCurrentProcessId();
+    DWORD pid = osGetCurrentProcessId();
     memcpy(&zBuf[n], &pid, sizeof(pid));
     n += sizeof(pid);
   }
-  if( sizeof(DWORD)<=nBuf-n ){
-    DWORD cnt = GetTickCount();
+#if SQLITE_OS_WINRT
+  if( sizeof(ULONGLONG)<=nBuf-n ){
+    ULONGLONG cnt = osGetTickCount64();
     memcpy(&zBuf[n], &cnt, sizeof(cnt));
     n += sizeof(cnt);
   }
+#else
+  if( sizeof(DWORD)<=nBuf-n ){
+    DWORD cnt = osGetTickCount();
+    memcpy(&zBuf[n], &cnt, sizeof(cnt));
+    n += sizeof(cnt);
+  }
+#endif
   if( sizeof(LARGE_INTEGER)<=nBuf-n ){
     LARGE_INTEGER i;
-    QueryPerformanceCounter(&i);
+    osQueryPerformanceCounter(&i);
     memcpy(&zBuf[n], &i, sizeof(i));
     n += sizeof(i);
   }
@@ -28672,59 +34074,90 @@ static int winRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
 ** Sleep for a little while.  Return the amount of time slept.
 */
 static int winSleep(sqlite3_vfs *pVfs, int microsec){
-  Sleep((microsec+999)/1000);
+  sqlite3_win32_sleep((microsec+999)/1000);
   UNUSED_PARAMETER(pVfs);
   return ((microsec+999)/1000)*1000;
 }
 
 /*
-** The following variable, if set to a non-zero value, becomes the result
-** returned from sqlite3OsCurrentTime().  This is used for testing.
+** The following variable, if set to a non-zero value, is interpreted as
+** the number of seconds since 1970 and is used to set the result of
+** sqlite3OsCurrentTime() during testing.
 */
 #ifdef SQLITE_TEST
-SQLITE_API int sqlite3_current_time = 0;
+SQLITE_API int sqlite3_current_time = 0;  /* Fake system time in seconds since 1970. */
 #endif
 
+/*
+** Find the current time (in Universal Coordinated Time).  Write into *piNow
+** the current time and date as a Julian Day number times 86_400_000.  In
+** other words, write into *piNow the number of milliseconds since the Julian
+** epoch of noon in Greenwich on November 24, 4714 B.C according to the
+** proleptic Gregorian calendar.
+**
+** On success, return SQLITE_OK.  Return SQLITE_ERROR if the time and date 
+** cannot be found.
+*/
+static int winCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *piNow){
+  /* FILETIME structure is a 64-bit value representing the number of 
+     100-nanosecond intervals since January 1, 1601 (= JD 2305813.5). 
+  */
+  FILETIME ft;
+  static const sqlite3_int64 winFiletimeEpoch = 23058135*(sqlite3_int64)8640000;
+#ifdef SQLITE_TEST
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+#endif
+  /* 2^32 - to avoid use of LL and warnings in gcc */
+  static const sqlite3_int64 max32BitValue = 
+      (sqlite3_int64)2000000000 + (sqlite3_int64)2000000000 + (sqlite3_int64)294967296;
+
+#if SQLITE_OS_WINCE
+  SYSTEMTIME time;
+  osGetSystemTime(&time);
+  /* if SystemTimeToFileTime() fails, it returns zero. */
+  if (!osSystemTimeToFileTime(&time,&ft)){
+    return SQLITE_ERROR;
+  }
+#else
+  osGetSystemTimeAsFileTime( &ft );
+#endif
+
+  *piNow = winFiletimeEpoch +
+            ((((sqlite3_int64)ft.dwHighDateTime)*max32BitValue) + 
+               (sqlite3_int64)ft.dwLowDateTime)/(sqlite3_int64)10000;
+
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
+  }
+#endif
+  UNUSED_PARAMETER(pVfs);
+  return SQLITE_OK;
+}
+
 /*
 ** Find the current time (in Universal Coordinated Time).  Write the
 ** current time and date as a Julian Day number into *prNow and
 ** return 0.  Return 1 if the time and date cannot be found.
 */
-int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
-  FILETIME ft;
-  /* FILETIME structure is a 64-bit value representing the number of 
-     100-nanosecond intervals since January 1, 1601 (= JD 2305813.5). 
-  */
-  double now;
-#if SQLITE_OS_WINCE
-  SYSTEMTIME time;
-  GetSystemTime(&time);
-  /* if SystemTimeToFileTime() fails, it returns zero. */
-  if (!SystemTimeToFileTime(&time,&ft)){
-    return 1;
+static int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
+  int rc;
+  sqlite3_int64 i;
+  rc = winCurrentTimeInt64(pVfs, &i);
+  if( !rc ){
+    *prNow = i/86400000.0;
   }
-#else
-  GetSystemTimeAsFileTime( &ft );
-#endif
-  UNUSED_PARAMETER(pVfs);
-  now = ((double)ft.dwHighDateTime) * 4294967296.0; 
-  *prNow = (now + ft.dwLowDateTime)/864000000000.0 + 2305813.5;
-#ifdef SQLITE_TEST
-  if( sqlite3_current_time ){
-    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
-  }
-#endif
-  return 0;
+  return rc;
 }
 
 /*
 ** The idea is that this function works like a combination of
-** GetLastError() and FormatMessage() on windows (or errno and
-** strerror_r() on unix). After an error is returned by an OS
+** GetLastError() and FormatMessage() on Windows (or errno and
+** strerror_r() on Unix). After an error is returned by an OS
 ** function, SQLite calls this function with zBuf pointing to
 ** a buffer of nBuf bytes. The OS layer should populate the
 ** buffer with a nul-terminated UTF-8 encoded error message
-** describing the last IO error to have occured within the calling
+** describing the last IO error to have occurred within the calling
 ** thread.
 **
 ** If the error message is too large for the supplied buffer,
@@ -28749,7 +34182,7 @@ int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
 */
 static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
   UNUSED_PARAMETER(pVfs);
-  return getLastErrorMsg(nBuf, zBuf);
+  return getLastErrorMsg(osGetLastError(), nBuf, zBuf);
 }
 
 /*
@@ -28757,30 +34190,56 @@ static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
 */
 SQLITE_API int sqlite3_os_init(void){
   static sqlite3_vfs winVfs = {
-    1,                 /* iVersion */
-    sizeof(winFile),   /* szOsFile */
-    MAX_PATH,          /* mxPathname */
-    0,                 /* pNext */
-    "win32",           /* zName */
-    0,                 /* pAppData */
- 
-    winOpen,           /* xOpen */
-    winDelete,         /* xDelete */
-    winAccess,         /* xAccess */
-    winFullPathname,   /* xFullPathname */
-    winDlOpen,         /* xDlOpen */
-    winDlError,        /* xDlError */
-    winDlSym,          /* xDlSym */
-    winDlClose,        /* xDlClose */
-    winRandomness,     /* xRandomness */
-    winSleep,          /* xSleep */
-    winCurrentTime,    /* xCurrentTime */
-    winGetLastError    /* xGetLastError */
+    3,                   /* iVersion */
+    sizeof(winFile),     /* szOsFile */
+    MAX_PATH,            /* mxPathname */
+    0,                   /* pNext */
+    "win32",             /* zName */
+    0,                   /* pAppData */
+    winOpen,             /* xOpen */
+    winDelete,           /* xDelete */
+    winAccess,           /* xAccess */
+    winFullPathname,     /* xFullPathname */
+    winDlOpen,           /* xDlOpen */
+    winDlError,          /* xDlError */
+    winDlSym,            /* xDlSym */
+    winDlClose,          /* xDlClose */
+    winRandomness,       /* xRandomness */
+    winSleep,            /* xSleep */
+    winCurrentTime,      /* xCurrentTime */
+    winGetLastError,     /* xGetLastError */
+    winCurrentTimeInt64, /* xCurrentTimeInt64 */
+    winSetSystemCall,    /* xSetSystemCall */
+    winGetSystemCall,    /* xGetSystemCall */
+    winNextSystemCall,   /* xNextSystemCall */
   };
+
+  /* Double-check that the aSyscall[] array has been constructed
+  ** correctly.  See ticket [bb3a86e890c8e96ab] */
+  assert( ArraySize(aSyscall)==73 );
+
+#ifndef SQLITE_OMIT_WAL
+  /* get memory map allocation granularity */
+  memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
+#if SQLITE_OS_WINRT
+  osGetNativeSystemInfo(&winSysInfo);
+#else
+  osGetSystemInfo(&winSysInfo);
+#endif
+  assert(winSysInfo.dwAllocationGranularity > 0);
+#endif
+
   sqlite3_vfs_register(&winVfs, 1);
   return SQLITE_OK; 
 }
+
 SQLITE_API int sqlite3_os_end(void){ 
+#if SQLITE_OS_WINRT
+  if( sleepObj != NULL ){
+    osCloseHandle(sleepObj);
+    sleepObj = NULL;
+  }
+#endif
   return SQLITE_OK;
 }
 
@@ -28823,8 +34282,6 @@ SQLITE_API int sqlite3_os_end(void){
 ** Bitvec object is the number of pages in the database file at the
 ** start of a transaction, and is thus usually less than a few thousand,
 ** but can be as large as 2 billion for a really big database.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /* Size of the Bitvec structure in bytes. */
@@ -28883,8 +34340,9 @@ SQLITE_API int sqlite3_os_end(void){
 */
 struct Bitvec {
   u32 iSize;      /* Maximum bit index.  Max iSize is 4,294,967,296. */
-  u32 nSet;       /* Number of bits that are set - only valid for aHash element */
-                  /* Max nSet is BITVEC_NINT.  For BITVEC_SZ of 512, this would be 125. */
+  u32 nSet;       /* Number of bits that are set - only valid for aHash
+                  ** element.  Max is BITVEC_NINT.  For BITVEC_SZ of 512,
+                  ** this would be 125. */
   u32 iDivisor;   /* Number of bits handled by each apSub[] entry. */
                   /* Should >=0 for apSub element. */
                   /* Max iDivisor is max(u32) / BITVEC_NPTR + 1.  */
@@ -28934,8 +34392,7 @@ SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec *p, u32 i){
     u32 h = BITVEC_HASH(i++);
     while( p->u.aHash[h] ){
       if( p->u.aHash[h]==i ) return 1;
-      h++;
-      if( h>=BITVEC_NINT ) h = 0;
+      h = (h+1) % BITVEC_NINT;
     }
     return 0;
   }
@@ -28955,7 +34412,7 @@ SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec *p, u32 i){
 */
 SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec *p, u32 i){
   u32 h;
-  assert( p!=0 );
+  if( p==0 ) return SQLITE_OK;
   assert( i>0 );
   assert( i<=p->iSize );
   i--;
@@ -28997,15 +34454,20 @@ bitvec_set_rehash:
   if( p->nSet>=BITVEC_MXHASH ){
     unsigned int j;
     int rc;
-    u32 aiValues[BITVEC_NINT];
-    memcpy(aiValues, p->u.aHash, sizeof(aiValues));
-    memset(p->u.apSub, 0, sizeof(aiValues));
-    p->iDivisor = (p->iSize + BITVEC_NPTR - 1)/BITVEC_NPTR;
-    rc = sqlite3BitvecSet(p, i);
-    for(j=0; j<BITVEC_NINT; j++){
-      if( aiValues[j] ) rc |= sqlite3BitvecSet(p, aiValues[j]);
+    u32 *aiValues = sqlite3StackAllocRaw(0, sizeof(p->u.aHash));
+    if( aiValues==0 ){
+      return SQLITE_NOMEM;
+    }else{
+      memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
+      memset(p->u.apSub, 0, sizeof(p->u.apSub));
+      p->iDivisor = (p->iSize + BITVEC_NPTR - 1)/BITVEC_NPTR;
+      rc = sqlite3BitvecSet(p, i);
+      for(j=0; j<BITVEC_NINT; j++){
+        if( aiValues[j] ) rc |= sqlite3BitvecSet(p, aiValues[j]);
+      }
+      sqlite3StackFree(0, aiValues);
+      return rc;
     }
-    return rc;
   }
 bitvec_set_end:
   p->nSet++;
@@ -29015,9 +34477,12 @@ bitvec_set_end:
 
 /*
 ** Clear the i-th bit.
+**
+** pBuf must be a pointer to at least BITVEC_SZ bytes of temporary storage
+** that BitvecClear can use to rebuilt its hash table.
 */
-SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec *p, u32 i){
-  assert( p!=0 );
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec *p, u32 i, void *pBuf){
+  if( p==0 ) return;
   assert( i>0 );
   i--;
   while( p->iDivisor ){
@@ -29032,9 +34497,9 @@ SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec *p, u32 i){
     p->u.aBitmap[i/BITVEC_SZELEM] &= ~(1 << (i&(BITVEC_SZELEM-1)));
   }else{
     unsigned int j;
-    u32 aiValues[BITVEC_NINT];
-    memcpy(aiValues, p->u.aHash, sizeof(aiValues));
-    memset(p->u.aHash, 0, sizeof(aiValues));
+    u32 *aiValues = pBuf;
+    memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
+    memset(p->u.aHash, 0, sizeof(p->u.aHash));
     p->nSet = 0;
     for(j=0; j<BITVEC_NINT; j++){
       if( aiValues[j] && aiValues[j]!=(i+1) ){
@@ -29064,6 +34529,14 @@ SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec *p){
   sqlite3_free(p);
 }
 
+/*
+** Return the value of the iSize parameter specified when Bitvec *p
+** was created.
+*/
+SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec *p){
+  return p->iSize;
+}
+
 #ifndef SQLITE_OMIT_BUILTIN_TEST
 /*
 ** Let V[] be an array of unsigned characters sufficient to hold
@@ -29110,13 +34583,18 @@ SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int sz, int *aOp){
   unsigned char *pV = 0;
   int rc = -1;
   int i, nx, pc, op;
+  void *pTmpSpace;
 
   /* Allocate the Bitvec to be tested and a linear array of
   ** bits to act as the reference */
   pBitvec = sqlite3BitvecCreate( sz );
-  pV = sqlite3_malloc( (sz+7)/8 + 1 );
-  if( pBitvec==0 || pV==0 ) goto bitvec_end;
-  memset(pV, 0, (sz+7)/8 + 1);
+  pV = sqlite3MallocZero( (sz+7)/8 + 1 );
+  pTmpSpace = sqlite3_malloc(BITVEC_SZ);
+  if( pBitvec==0 || pV==0 || pTmpSpace==0  ) goto bitvec_end;
+
+  /* NULL pBitvec tests */
+  sqlite3BitvecSet(0, 1);
+  sqlite3BitvecClear(0, 1, pTmpSpace);
 
   /* Run the program */
   pc = 0;
@@ -29148,7 +34626,7 @@ SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int sz, int *aOp){
       }
     }else{
       CLEARBIT(pV, (i+1));
-      sqlite3BitvecClear(pBitvec, i+1);
+      sqlite3BitvecClear(pBitvec, i+1, pTmpSpace);
     }
   }
 
@@ -29158,7 +34636,8 @@ SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int sz, int *aOp){
   ** is found.
   */
   rc = sqlite3BitvecTest(0,0) + sqlite3BitvecTest(pBitvec, sz+1)
-          + sqlite3BitvecTest(pBitvec, 0);
+          + sqlite3BitvecTest(pBitvec, 0)
+          + (sqlite3BitvecSize(pBitvec) - sz);
   for(i=1; i<=sz; i++){
     if(  (TESTBIT(pV,i))!=sqlite3BitvecTest(pBitvec,i) ){
       rc = i;
@@ -29168,6 +34647,7 @@ SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int sz, int *aOp){
 
   /* Free allocated structure */
 bitvec_end:
+  sqlite3_free(pTmpSpace);
   sqlite3_free(pV);
   sqlite3BitvecDestroy(pBitvec);
   return rc;
@@ -29188,8 +34668,6 @@ bitvec_end:
 **
 *************************************************************************
 ** This file implements that page cache.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -29199,15 +34677,14 @@ struct PCache {
   PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
   PgHdr *pSynced;                     /* Last synced page in dirty page list */
   int nRef;                           /* Number of referenced pages */
-  int nMax;                           /* Configured cache size */
-  int nMin;                           /* Configured minimum cache size */
+  int szCache;                        /* Configured cache size */
   int szPage;                         /* Size of every page in this cache */
   int szExtra;                        /* Size of extra space for each page */
   int bPurgeable;                     /* True if pages are on backing store */
   int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
   void *pStress;                      /* Argument to xStress */
   sqlite3_pcache *pCache;             /* Pluggable cache module */
-  PgHdr *pPage1;
+  PgHdr *pPage1;                      /* Reference to page 1 */
 };
 
 /*
@@ -29311,7 +34788,7 @@ static void pcacheUnpin(PgHdr *p){
     if( p->pgno==1 ){
       pCache->pPage1 = 0;
     }
-    sqlite3GlobalConfig.pcache.xUnpin(pCache->pCache, p, 0);
+    sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 0);
   }
 }
 
@@ -29321,14 +34798,18 @@ static void pcacheUnpin(PgHdr *p){
 ** functions are threadsafe.
 */
 SQLITE_PRIVATE int sqlite3PcacheInitialize(void){
-  if( sqlite3GlobalConfig.pcache.xInit==0 ){
+  if( sqlite3GlobalConfig.pcache2.xInit==0 ){
+    /* IMPLEMENTATION-OF: R-26801-64137 If the xInit() method is NULL, then the
+    ** built-in default page cache is used instead of the application defined
+    ** page cache. */
     sqlite3PCacheSetDefault();
   }
-  return sqlite3GlobalConfig.pcache.xInit(sqlite3GlobalConfig.pcache.pArg);
+  return sqlite3GlobalConfig.pcache2.xInit(sqlite3GlobalConfig.pcache2.pArg);
 }
 SQLITE_PRIVATE void sqlite3PcacheShutdown(void){
-  if( sqlite3GlobalConfig.pcache.xShutdown ){
-    sqlite3GlobalConfig.pcache.xShutdown(sqlite3GlobalConfig.pcache.pArg);
+  if( sqlite3GlobalConfig.pcache2.xShutdown ){
+    /* IMPLEMENTATION-OF: R-26000-56589 The xShutdown() method may be NULL. */
+    sqlite3GlobalConfig.pcache2.xShutdown(sqlite3GlobalConfig.pcache2.pArg);
   }
 }
 
@@ -29357,8 +34838,7 @@ SQLITE_PRIVATE void sqlite3PcacheOpen(
   p->bPurgeable = bPurgeable;
   p->xStress = xStress;
   p->pStress = pStress;
-  p->nMax = 100;
-  p->nMin = 10;
+  p->szCache = 100;
 }
 
 /*
@@ -29368,12 +34848,24 @@ SQLITE_PRIVATE void sqlite3PcacheOpen(
 SQLITE_PRIVATE void sqlite3PcacheSetPageSize(PCache *pCache, int szPage){
   assert( pCache->nRef==0 && pCache->pDirty==0 );
   if( pCache->pCache ){
-    sqlite3GlobalConfig.pcache.xDestroy(pCache->pCache);
+    sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
     pCache->pCache = 0;
+    pCache->pPage1 = 0;
   }
   pCache->szPage = szPage;
 }
 
+/*
+** Compute the number of pages of cache requested.
+*/
+static int numberOfCachePages(PCache *p){
+  if( p->szCache>=0 ){
+    return p->szCache;
+  }else{
+    return (int)((-1024*(i64)p->szCache)/(p->szPage+p->szExtra));
+  }
+}
+
 /*
 ** Try to obtain a page from the cache.
 */
@@ -29383,10 +34875,12 @@ SQLITE_PRIVATE int sqlite3PcacheFetch(
   int createFlag,       /* If true, create page if it does not exist already */
   PgHdr **ppPage        /* Write the page here */
 ){
-  PgHdr *pPage = 0;
+  sqlite3_pcache_page *pPage = 0;
+  PgHdr *pPgHdr = 0;
   int eCreate;
 
   assert( pCache!=0 );
+  assert( createFlag==1 || createFlag==0 );
   assert( pgno>0 );
 
   /* If the pluggable cache (sqlite3_pcache*) has not been allocated,
@@ -29394,22 +34888,19 @@ SQLITE_PRIVATE int sqlite3PcacheFetch(
   */
   if( !pCache->pCache && createFlag ){
     sqlite3_pcache *p;
-    int nByte;
-    nByte = pCache->szPage + pCache->szExtra + sizeof(PgHdr);
-    p = sqlite3GlobalConfig.pcache.xCreate(nByte, pCache->bPurgeable);
+    p = sqlite3GlobalConfig.pcache2.xCreate(
+        pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
+    );
     if( !p ){
       return SQLITE_NOMEM;
     }
-    sqlite3GlobalConfig.pcache.xCachesize(p, pCache->nMax);
+    sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
     pCache->pCache = p;
   }
 
-  eCreate = createFlag ? 1 : 0;
-  if( eCreate && (!pCache->bPurgeable || !pCache->pDirty) ){
-    eCreate = 2;
-  }
+  eCreate = createFlag * (1 + (!pCache->bPurgeable || !pCache->pDirty));
   if( pCache->pCache ){
-    pPage = sqlite3GlobalConfig.pcache.xFetch(pCache->pCache, pgno, eCreate);
+    pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
   }
 
   if( !pPage && eCreate==1 ){
@@ -29425,35 +34916,55 @@ SQLITE_PRIVATE int sqlite3PcacheFetch(
         pPg && (pPg->nRef || (pPg->flags&PGHDR_NEED_SYNC)); 
         pPg=pPg->pDirtyPrev
     );
+    pCache->pSynced = pPg;
     if( !pPg ){
       for(pPg=pCache->pDirtyTail; pPg && pPg->nRef; pPg=pPg->pDirtyPrev);
     }
     if( pPg ){
       int rc;
+#ifdef SQLITE_LOG_CACHE_SPILL
+      sqlite3_log(SQLITE_FULL, 
+                  "spill page %d making room for %d - cache used: %d/%d",
+                  pPg->pgno, pgno,
+                  sqlite3GlobalConfig.pcache.xPagecount(pCache->pCache),
+                  numberOfCachePages(pCache));
+#endif
       rc = pCache->xStress(pCache->pStress, pPg);
       if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
         return rc;
       }
     }
 
-    pPage = sqlite3GlobalConfig.pcache.xFetch(pCache->pCache, pgno, 2);
+    pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, 2);
   }
 
   if( pPage ){
-    if( 0==pPage->nRef ){
+    pPgHdr = (PgHdr *)pPage->pExtra;
+
+    if( !pPgHdr->pPage ){
+      memset(pPgHdr, 0, sizeof(PgHdr));
+      pPgHdr->pPage = pPage;
+      pPgHdr->pData = pPage->pBuf;
+      pPgHdr->pExtra = (void *)&pPgHdr[1];
+      memset(pPgHdr->pExtra, 0, pCache->szExtra);
+      pPgHdr->pCache = pCache;
+      pPgHdr->pgno = pgno;
+    }
+    assert( pPgHdr->pCache==pCache );
+    assert( pPgHdr->pgno==pgno );
+    assert( pPgHdr->pData==pPage->pBuf );
+    assert( pPgHdr->pExtra==(void *)&pPgHdr[1] );
+
+    if( 0==pPgHdr->nRef ){
       pCache->nRef++;
     }
-    pPage->nRef++;
-    pPage->pData = (void*)&pPage[1];
-    pPage->pExtra = (void*)&((char*)pPage->pData)[pCache->szPage];
-    pPage->pCache = pCache;
-    pPage->pgno = pgno;
+    pPgHdr->nRef++;
     if( pgno==1 ){
-      pCache->pPage1 = pPage;
+      pCache->pPage1 = pPgHdr;
     }
   }
-  *ppPage = pPage;
-  return (pPage==0 && eCreate) ? SQLITE_NOMEM : SQLITE_OK;
+  *ppPage = pPgHdr;
+  return (pPgHdr==0 && eCreate) ? SQLITE_NOMEM : SQLITE_OK;
 }
 
 /*
@@ -29500,7 +35011,7 @@ SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr *p){
   if( p->pgno==1 ){
     pCache->pPage1 = 0;
   }
-  sqlite3GlobalConfig.pcache.xUnpin(pCache->pCache, p, 1);
+  sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 1);
 }
 
 /*
@@ -29508,11 +35019,9 @@ SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr *p){
 ** make it so.
 */
 SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr *p){
-  PCache *pCache;
   p->flags &= ~PGHDR_DONT_WRITE;
   assert( p->nRef>0 );
   if( 0==(p->flags & PGHDR_DIRTY) ){
-    pCache = p->pCache;
     p->flags |= PGHDR_DIRTY;
     pcacheAddToDirtyList( p);
   }
@@ -29560,7 +35069,7 @@ SQLITE_PRIVATE void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
   PCache *pCache = p->pCache;
   assert( p->nRef>0 );
   assert( newPgno>0 );
-  sqlite3GlobalConfig.pcache.xRekey(pCache->pCache, p, p->pgno, newPgno);
+  sqlite3GlobalConfig.pcache2.xRekey(pCache->pCache, p->pPage, p->pgno,newPgno);
   p->pgno = newPgno;
   if( (p->flags&PGHDR_DIRTY) && (p->flags&PGHDR_NEED_SYNC) ){
     pcacheRemoveFromDirtyList(p);
@@ -29583,7 +35092,12 @@ SQLITE_PRIVATE void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
     PgHdr *pNext;
     for(p=pCache->pDirty; p; p=pNext){
       pNext = p->pDirtyNext;
-      if( p->pgno>pgno ){
+      /* This routine never gets call with a positive pgno except right
+      ** after sqlite3PcacheCleanAll().  So if there are dirty pages,
+      ** it must be that pgno==0.
+      */
+      assert( p->pgno>0 );
+      if( ALWAYS(p->pgno>pgno) ){
         assert( p->flags&PGHDR_DIRTY );
         sqlite3PcacheMakeClean(p);
       }
@@ -29592,7 +35106,7 @@ SQLITE_PRIVATE void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
       memset(pCache->pPage1->pData, 0, pCache->szPage);
       pgno = 1;
     }
-    sqlite3GlobalConfig.pcache.xTruncate(pCache->pCache, pgno+1);
+    sqlite3GlobalConfig.pcache2.xTruncate(pCache->pCache, pgno+1);
   }
 }
 
@@ -29601,16 +35115,15 @@ SQLITE_PRIVATE void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
 */
 SQLITE_PRIVATE void sqlite3PcacheClose(PCache *pCache){
   if( pCache->pCache ){
-    sqlite3GlobalConfig.pcache.xDestroy(pCache->pCache);
+    sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
   }
 }
 
 /* 
 ** Discard the contents of the cache.
 */
-SQLITE_PRIVATE int sqlite3PcacheClear(PCache *pCache){
+SQLITE_PRIVATE void sqlite3PcacheClear(PCache *pCache){
   sqlite3PcacheTruncate(pCache, 0);
-  return SQLITE_OK;
 }
 
 /*
@@ -29645,24 +35158,22 @@ static PgHdr *pcacheMergeDirtyList(PgHdr *pA, PgHdr *pB){
 ** Sort the list of pages in accending order by pgno.  Pages are
 ** connected by pDirty pointers.  The pDirtyPrev pointers are
 ** corrupted by this sort.
+**
+** Since there cannot be more than 2^31 distinct pages in a database,
+** there cannot be more than 31 buckets required by the merge sorter.
+** One extra bucket is added to catch overflow in case something
+** ever changes to make the previous sentence incorrect.
 */
-#define N_SORT_BUCKET_ALLOC 25
-#define N_SORT_BUCKET       25
-#ifdef SQLITE_TEST
-  int sqlite3_pager_n_sort_bucket = 0;
-  #undef N_SORT_BUCKET
-  #define N_SORT_BUCKET \
-   (sqlite3_pager_n_sort_bucket?sqlite3_pager_n_sort_bucket:N_SORT_BUCKET_ALLOC)
-#endif
+#define N_SORT_BUCKET  32
 static PgHdr *pcacheSortDirtyList(PgHdr *pIn){
-  PgHdr *a[N_SORT_BUCKET_ALLOC], *p;
+  PgHdr *a[N_SORT_BUCKET], *p;
   int i;
   memset(a, 0, sizeof(a));
   while( pIn ){
     p = pIn;
     pIn = p->pDirty;
     p->pDirty = 0;
-    for(i=0; i<N_SORT_BUCKET-1; i++){
+    for(i=0; ALWAYS(i<N_SORT_BUCKET-1); i++){
       if( a[i]==0 ){
         a[i] = p;
         break;
@@ -29671,11 +35182,9 @@ static PgHdr *pcacheSortDirtyList(PgHdr *pIn){
         a[i] = 0;
       }
     }
-    if( i==N_SORT_BUCKET-1 ){
-      /* Coverage: To get here, there need to be 2^(N_SORT_BUCKET) 
-      ** elements in the input list. This is possible, but impractical.
-      ** Testing this line is the point of global variable
-      ** sqlite3_pager_n_sort_bucket.
+    if( NEVER(i==N_SORT_BUCKET-1) ){
+      /* To get here, there need to be 2^(N_SORT_BUCKET) elements in
+      ** the input list.  But that is impossible.
       */
       a[i] = pcacheMergeDirtyList(a[i], p);
     }
@@ -29718,7 +35227,7 @@ SQLITE_PRIVATE int sqlite3PcachePageRefcount(PgHdr *p){
 SQLITE_PRIVATE int sqlite3PcachePagecount(PCache *pCache){
   int nPage = 0;
   if( pCache->pCache ){
-    nPage = sqlite3GlobalConfig.pcache.xPagecount(pCache->pCache);
+    nPage = sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache);
   }
   return nPage;
 }
@@ -29728,7 +35237,7 @@ SQLITE_PRIVATE int sqlite3PcachePagecount(PCache *pCache){
 ** Get the suggested cache-size value.
 */
 SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *pCache){
-  return pCache->nMax;
+  return numberOfCachePages(pCache);
 }
 #endif
 
@@ -29736,13 +35245,23 @@ SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *pCache){
 ** Set the suggested cache-size value.
 */
 SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){
-  pCache->nMax = mxPage;
+  pCache->szCache = mxPage;
   if( pCache->pCache ){
-    sqlite3GlobalConfig.pcache.xCachesize(pCache->pCache, mxPage);
+    sqlite3GlobalConfig.pcache2.xCachesize(pCache->pCache,
+                                           numberOfCachePages(pCache));
   }
 }
 
-#ifdef SQLITE_CHECK_PAGES
+/*
+** Free up as much memory as possible from the page cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheShrink(PCache *pCache){
+  if( pCache->pCache ){
+    sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache);
+  }
+}
+
+#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
 /*
 ** For all dirty pages currently in the cache, invoke the specified
 ** callback. This is only used if the SQLITE_CHECK_PAGES macro is
@@ -29775,48 +35294,85 @@ SQLITE_PRIVATE void sqlite3PcacheIterateDirty(PCache *pCache, void (*xIter)(PgHd
 ** of the SQLITE_CONFIG_PAGECACHE and sqlite3_release_memory() features.
 ** If the default page cache implementation is overriden, then neither of
 ** these two features are available.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
 typedef struct PCache1 PCache1;
 typedef struct PgHdr1 PgHdr1;
 typedef struct PgFreeslot PgFreeslot;
+typedef struct PGroup PGroup;
 
-/* Pointers to structures of this type are cast and returned as 
-** opaque sqlite3_pcache* handles
+/* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set 
+** of one or more PCaches that are able to recycle each others unpinned
+** pages when they are under memory pressure.  A PGroup is an instance of
+** the following object.
+**
+** This page cache implementation works in one of two modes:
+**
+**   (1)  Every PCache is the sole member of its own PGroup.  There is
+**        one PGroup per PCache.
+**
+**   (2)  There is a single global PGroup that all PCaches are a member
+**        of.
+**
+** Mode 1 uses more memory (since PCache instances are not able to rob
+** unused pages from other PCaches) but it also operates without a mutex,
+** and is therefore often faster.  Mode 2 requires a mutex in order to be
+** threadsafe, but recycles pages more efficiently.
+**
+** For mode (1), PGroup.mutex is NULL.  For mode (2) there is only a single
+** PGroup which is the pcache1.grp global variable and its mutex is
+** SQLITE_MUTEX_STATIC_LRU.
+*/
+struct PGroup {
+  sqlite3_mutex *mutex;          /* MUTEX_STATIC_LRU or NULL */
+  unsigned int nMaxPage;         /* Sum of nMax for purgeable caches */
+  unsigned int nMinPage;         /* Sum of nMin for purgeable caches */
+  unsigned int mxPinned;         /* nMaxpage + 10 - nMinPage */
+  unsigned int nCurrentPage;     /* Number of purgeable pages allocated */
+  PgHdr1 *pLruHead, *pLruTail;   /* LRU list of unpinned pages */
+};
+
+/* Each page cache is an instance of the following object.  Every
+** open database file (including each in-memory database and each
+** temporary or transient database) has a single page cache which
+** is an instance of this object.
+**
+** Pointers to structures of this type are cast and returned as 
+** opaque sqlite3_pcache* handles.
 */
 struct PCache1 {
   /* Cache configuration parameters. Page size (szPage) and the purgeable
   ** flag (bPurgeable) are set when the cache is created. nMax may be 
-  ** modified at any time by a call to the pcache1CacheSize() method.
-  ** The global mutex must be held when accessing nMax.
+  ** modified at any time by a call to the pcache1Cachesize() method.
+  ** The PGroup mutex must be held when accessing nMax.
   */
+  PGroup *pGroup;                     /* PGroup this cache belongs to */
   int szPage;                         /* Size of allocated pages in bytes */
+  int szExtra;                        /* Size of extra space in bytes */
   int bPurgeable;                     /* True if cache is purgeable */
   unsigned int nMin;                  /* Minimum number of pages reserved */
   unsigned int nMax;                  /* Configured "cache_size" value */
+  unsigned int n90pct;                /* nMax*9/10 */
+  unsigned int iMaxKey;               /* Largest key seen since xTruncate() */
 
   /* Hash table of all pages. The following variables may only be accessed
-  ** when the accessor is holding the global mutex (see pcache1EnterMutex() 
-  ** and pcache1LeaveMutex()).
+  ** when the accessor is holding the PGroup mutex.
   */
   unsigned int nRecyclable;           /* Number of pages in the LRU list */
   unsigned int nPage;                 /* Total number of pages in apHash */
   unsigned int nHash;                 /* Number of slots in apHash[] */
   PgHdr1 **apHash;                    /* Hash table for fast lookup by key */
-
-  unsigned int iMaxKey;               /* Largest key seen since xTruncate() */
 };
 
 /*
 ** Each cache entry is represented by an instance of the following 
-** structure. A buffer of PgHdr1.pCache->szPage bytes is allocated 
-** directly after the structure in memory (see the PGHDR1_TO_PAGE() 
-** macro below).
+** structure. Unless SQLITE_PCACHE_SEPARATE_HEADER is defined, a buffer of
+** PgHdr1.pCache->szPage bytes is allocated directly before this structure 
+** in memory.
 */
 struct PgHdr1 {
+  sqlite3_pcache_page page;
   unsigned int iKey;             /* Key value (page number) */
   PgHdr1 *pNext;                 /* Next in hash table chain */
   PCache1 *pCache;               /* Cache that currently owns this page */
@@ -29836,17 +35392,27 @@ struct PgFreeslot {
 ** Global data used by this cache.
 */
 static SQLITE_WSD struct PCacheGlobal {
-  sqlite3_mutex *mutex;               /* static mutex MUTEX_STATIC_LRU */
+  PGroup grp;                    /* The global PGroup for mode (2) */
 
-  int nMaxPage;                       /* Sum of nMaxPage for purgeable caches */
-  int nMinPage;                       /* Sum of nMinPage for purgeable caches */
-  int nCurrentPage;                   /* Number of purgeable pages allocated */
-  PgHdr1 *pLruHead, *pLruTail;        /* LRU list of unpinned pages */
-
-  /* Variables related to SQLITE_CONFIG_PAGECACHE settings. */
-  int szSlot;                         /* Size of each free slot */
-  void *pStart, *pEnd;                /* Bounds of pagecache malloc range */
-  PgFreeslot *pFree;                  /* Free page blocks */
+  /* Variables related to SQLITE_CONFIG_PAGECACHE settings.  The
+  ** szSlot, nSlot, pStart, pEnd, nReserve, and isInit values are all
+  ** fixed at sqlite3_initialize() time and do not require mutex protection.
+  ** The nFreeSlot and pFree values do require mutex protection.
+  */
+  int isInit;                    /* True if initialized */
+  int szSlot;                    /* Size of each free slot */
+  int nSlot;                     /* The number of pcache slots */
+  int nReserve;                  /* Try to keep nFreeSlot above this */
+  void *pStart, *pEnd;           /* Bounds of pagecache malloc range */
+  /* Above requires no mutex.  Use mutex below for variable that follow. */
+  sqlite3_mutex *mutex;          /* Mutex for accessing the following: */
+  PgFreeslot *pFree;             /* Free page blocks */
+  int nFreeSlot;                 /* Number of unused pcache slots */
+  /* The following value requires a mutex to change.  We skip the mutex on
+  ** reading because (1) most platforms read a 32-bit integer atomically and
+  ** (2) even if an incorrect value is read, no great harm is done since this
+  ** is really just an optimization. */
+  int bUnderPressure;            /* True if low on PAGECACHE memory */
 } pcache1_g;
 
 /*
@@ -29857,25 +35423,10 @@ static SQLITE_WSD struct PCacheGlobal {
 #define pcache1 (GLOBAL(struct PCacheGlobal, pcache1_g))
 
 /*
-** When a PgHdr1 structure is allocated, the associated PCache1.szPage
-** bytes of data are located directly after it in memory (i.e. the total
-** size of the allocation is sizeof(PgHdr1)+PCache1.szPage byte). The
-** PGHDR1_TO_PAGE() macro takes a pointer to a PgHdr1 structure as
-** an argument and returns a pointer to the associated block of szPage
-** bytes. The PAGE_TO_PGHDR1() macro does the opposite: its argument is
-** a pointer to a block of szPage bytes of data and the return value is
-** a pointer to the associated PgHdr1 structure.
-**
-**   assert( PGHDR1_TO_PAGE(PAGE_TO_PGHDR1(X))==X );
+** Macros to enter and leave the PCache LRU mutex.
 */
-#define PGHDR1_TO_PAGE(p) (void *)(&((unsigned char *)p)[sizeof(PgHdr1)])
-#define PAGE_TO_PGHDR1(p) (PgHdr1 *)(&((unsigned char *)p)[-1*(int)sizeof(PgHdr1)])
-
-/*
-** Macros to enter and leave the global LRU mutex.
-*/
-#define pcache1EnterMutex() sqlite3_mutex_enter(pcache1.mutex)
-#define pcache1LeaveMutex() sqlite3_mutex_leave(pcache1.mutex)
+#define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex)
+#define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex)
 
 /******************************************************************************/
 /******** Page Allocation/SQLITE_CONFIG_PCACHE Related Functions **************/
@@ -29885,20 +35436,28 @@ static SQLITE_WSD struct PCacheGlobal {
 ** supplied to use for the page-cache by passing the SQLITE_CONFIG_PAGECACHE
 ** verb to sqlite3_config(). Parameter pBuf points to an allocation large
 ** enough to contain 'n' buffers of 'sz' bytes each.
+**
+** This routine is called from sqlite3_initialize() and so it is guaranteed
+** to be serialized already.  There is no need for further mutexing.
 */
 SQLITE_PRIVATE void sqlite3PCacheBufferSetup(void *pBuf, int sz, int n){
-  PgFreeslot *p;
-  sz &= ~7;
-  pcache1.szSlot = sz;
-  pcache1.pStart = pBuf;
-  pcache1.pFree = 0;
-  while( n-- ){
-    p = (PgFreeslot*)pBuf;
-    p->pNext = pcache1.pFree;
-    pcache1.pFree = p;
-    pBuf = (void*)&((char*)pBuf)[sz];
+  if( pcache1.isInit ){
+    PgFreeslot *p;
+    sz = ROUNDDOWN8(sz);
+    pcache1.szSlot = sz;
+    pcache1.nSlot = pcache1.nFreeSlot = n;
+    pcache1.nReserve = n>90 ? 10 : (n/10 + 1);
+    pcache1.pStart = pBuf;
+    pcache1.pFree = 0;
+    pcache1.bUnderPressure = 0;
+    while( n-- ){
+      p = (PgFreeslot*)pBuf;
+      p->pNext = pcache1.pFree;
+      pcache1.pFree = p;
+      pBuf = (void*)&((char*)pBuf)[sz];
+    }
+    pcache1.pEnd = pBuf;
   }
-  pcache1.pEnd = pBuf;
 }
 
 /*
@@ -29906,30 +35465,40 @@ SQLITE_PRIVATE void sqlite3PCacheBufferSetup(void *pBuf, int sz, int n){
 ** configured using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no 
 ** such buffer exists or there is no space left in it, this function falls 
 ** back to sqlite3Malloc().
+**
+** Multiple threads can run this routine at the same time.  Global variables
+** in pcache1 need to be protected via mutex.
 */
 static void *pcache1Alloc(int nByte){
-  void *p;
-  assert( sqlite3_mutex_held(pcache1.mutex) );
-  if( nByte<=pcache1.szSlot && pcache1.pFree ){
+  void *p = 0;
+  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
+  sqlite3StatusSet(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
+  if( nByte<=pcache1.szSlot ){
+    sqlite3_mutex_enter(pcache1.mutex);
     p = (PgHdr1 *)pcache1.pFree;
-    pcache1.pFree = pcache1.pFree->pNext;
-    sqlite3StatusSet(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
-    sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, 1);
-  }else{
-
-    /* Allocate a new buffer using sqlite3Malloc. Before doing so, exit the
-    ** global pcache mutex and unlock the pager-cache object pCache. This is 
-    ** so that if the attempt to allocate a new buffer causes the the 
-    ** configured soft-heap-limit to be breached, it will be possible to
-    ** reclaim memory from this pager-cache.
+    if( p ){
+      pcache1.pFree = pcache1.pFree->pNext;
+      pcache1.nFreeSlot--;
+      pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
+      assert( pcache1.nFreeSlot>=0 );
+      sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, 1);
+    }
+    sqlite3_mutex_leave(pcache1.mutex);
+  }
+  if( p==0 ){
+    /* Memory is not available in the SQLITE_CONFIG_PAGECACHE pool.  Get
+    ** it from sqlite3Malloc instead.
     */
-    pcache1LeaveMutex();
     p = sqlite3Malloc(nByte);
-    pcache1EnterMutex();
+#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
     if( p ){
       int sz = sqlite3MallocSize(p);
+      sqlite3_mutex_enter(pcache1.mutex);
       sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, sz);
+      sqlite3_mutex_leave(pcache1.mutex);
     }
+#endif
+    sqlite3MemdebugSetType(p, MEMTYPE_PCACHE);
   }
   return p;
 }
@@ -29937,46 +35506,107 @@ static void *pcache1Alloc(int nByte){
 /*
 ** Free an allocated buffer obtained from pcache1Alloc().
 */
-static void pcache1Free(void *p){
-  assert( sqlite3_mutex_held(pcache1.mutex) );
-  if( p==0 ) return;
+static int pcache1Free(void *p){
+  int nFreed = 0;
+  if( p==0 ) return 0;
   if( p>=pcache1.pStart && p<pcache1.pEnd ){
     PgFreeslot *pSlot;
+    sqlite3_mutex_enter(pcache1.mutex);
     sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, -1);
     pSlot = (PgFreeslot*)p;
     pSlot->pNext = pcache1.pFree;
     pcache1.pFree = pSlot;
+    pcache1.nFreeSlot++;
+    pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
+    assert( pcache1.nFreeSlot<=pcache1.nSlot );
+    sqlite3_mutex_leave(pcache1.mutex);
   }else{
-    int iSize = sqlite3MallocSize(p);
-    sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, -iSize);
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
+    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+    nFreed = sqlite3MallocSize(p);
+#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
+    sqlite3_mutex_enter(pcache1.mutex);
+    sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, -nFreed);
+    sqlite3_mutex_leave(pcache1.mutex);
+#endif
     sqlite3_free(p);
   }
+  return nFreed;
 }
 
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/*
+** Return the size of a pcache allocation
+*/
+static int pcache1MemSize(void *p){
+  if( p>=pcache1.pStart && p<pcache1.pEnd ){
+    return pcache1.szSlot;
+  }else{
+    int iSize;
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
+    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+    iSize = sqlite3MallocSize(p);
+    sqlite3MemdebugSetType(p, MEMTYPE_PCACHE);
+    return iSize;
+  }
+}
+#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
+
 /*
 ** Allocate a new page object initially associated with cache pCache.
 */
 static PgHdr1 *pcache1AllocPage(PCache1 *pCache){
-  int nByte = sizeof(PgHdr1) + pCache->szPage;
-  PgHdr1 *p = (PgHdr1 *)pcache1Alloc(nByte);
-  if( p ){
-    memset(p, 0, nByte);
-    if( pCache->bPurgeable ){
-      pcache1.nCurrentPage++;
-    }
+  PgHdr1 *p = 0;
+  void *pPg;
+
+  /* The group mutex must be released before pcache1Alloc() is called. This
+  ** is because it may call sqlite3_release_memory(), which assumes that 
+  ** this mutex is not held. */
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  pcache1LeaveMutex(pCache->pGroup);
+#ifdef SQLITE_PCACHE_SEPARATE_HEADER
+  pPg = pcache1Alloc(pCache->szPage);
+  p = sqlite3Malloc(sizeof(PgHdr1) + pCache->szExtra);
+  if( !pPg || !p ){
+    pcache1Free(pPg);
+    sqlite3_free(p);
+    pPg = 0;
   }
-  return p;
+#else
+  pPg = pcache1Alloc(sizeof(PgHdr1) + pCache->szPage + pCache->szExtra);
+  p = (PgHdr1 *)&((u8 *)pPg)[pCache->szPage];
+#endif
+  pcache1EnterMutex(pCache->pGroup);
+
+  if( pPg ){
+    p->page.pBuf = pPg;
+    p->page.pExtra = &p[1];
+    if( pCache->bPurgeable ){
+      pCache->pGroup->nCurrentPage++;
+    }
+    return p;
+  }
+  return 0;
 }
 
 /*
 ** Free a page object allocated by pcache1AllocPage().
+**
+** The pointer is allowed to be NULL, which is prudent.  But it turns out
+** that the current implementation happens to never call this routine
+** with a NULL pointer, so we mark the NULL test with ALWAYS().
 */
 static void pcache1FreePage(PgHdr1 *p){
-  if( p ){
-    if( p->pCache->bPurgeable ){
-      pcache1.nCurrentPage--;
+  if( ALWAYS(p) ){
+    PCache1 *pCache = p->pCache;
+    assert( sqlite3_mutex_held(p->pCache->pGroup->mutex) );
+    pcache1Free(p->page.pBuf);
+#ifdef SQLITE_PCACHE_SEPARATE_HEADER
+    sqlite3_free(p);
+#endif
+    if( pCache->bPurgeable ){
+      pCache->pGroup->nCurrentPage--;
     }
-    pcache1Free(p);
   }
 }
 
@@ -29986,20 +35616,39 @@ static void pcache1FreePage(PgHdr1 *p){
 ** exists, this function falls back to sqlite3Malloc().
 */
 SQLITE_PRIVATE void *sqlite3PageMalloc(int sz){
-  void *p;
-  pcache1EnterMutex();
-  p = pcache1Alloc(sz);
-  pcache1LeaveMutex();
-  return p;
+  return pcache1Alloc(sz);
 }
 
 /*
 ** Free an allocated buffer obtained from sqlite3PageMalloc().
 */
 SQLITE_PRIVATE void sqlite3PageFree(void *p){
-  pcache1EnterMutex();
   pcache1Free(p);
-  pcache1LeaveMutex();
+}
+
+
+/*
+** Return true if it desirable to avoid allocating a new page cache
+** entry.
+**
+** If memory was allocated specifically to the page cache using
+** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then
+** it is desirable to avoid allocating a new page cache entry because
+** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient
+** for all page cache needs and we should not need to spill the
+** allocation onto the heap.
+**
+** Or, the heap is used for all page cache memory but the heap is
+** under memory pressure, then again it is desirable to avoid
+** allocating a new page cache entry in order to avoid stressing
+** the heap even further.
+*/
+static int pcache1UnderMemoryPressure(PCache1 *pCache){
+  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
+    return pcache1.bUnderPressure;
+  }else{
+    return sqlite3HeapNearlyFull();
+  }
 }
 
 /******************************************************************************/
@@ -30009,27 +35658,26 @@ SQLITE_PRIVATE void sqlite3PageFree(void *p){
 ** This function is used to resize the hash table used by the cache passed
 ** as the first argument.
 **
-** The global mutex must be held when this function is called.
+** The PCache mutex must be held when this function is called.
 */
 static int pcache1ResizeHash(PCache1 *p){
   PgHdr1 **apNew;
   unsigned int nNew;
   unsigned int i;
 
-  assert( sqlite3_mutex_held(pcache1.mutex) );
+  assert( sqlite3_mutex_held(p->pGroup->mutex) );
 
   nNew = p->nHash*2;
   if( nNew<256 ){
     nNew = 256;
   }
 
-  pcache1LeaveMutex();
+  pcache1LeaveMutex(p->pGroup);
   if( p->nHash ){ sqlite3BeginBenignMalloc(); }
-  apNew = (PgHdr1 **)sqlite3_malloc(sizeof(PgHdr1 *)*nNew);
+  apNew = (PgHdr1 **)sqlite3MallocZero(sizeof(PgHdr1 *)*nNew);
   if( p->nHash ){ sqlite3EndBenignMalloc(); }
-  pcache1EnterMutex();
+  pcache1EnterMutex(p->pGroup);
   if( apNew ){
-    memset(apNew, 0, sizeof(PgHdr1 *)*nNew);
     for(i=0; i<p->nHash; i++){
       PgHdr1 *pPage;
       PgHdr1 *pNext = p->apHash[i];
@@ -30050,25 +35698,33 @@ static int pcache1ResizeHash(PCache1 *p){
 
 /*
 ** This function is used internally to remove the page pPage from the 
-** global LRU list, if is part of it. If pPage is not part of the global
+** PGroup LRU list, if is part of it. If pPage is not part of the PGroup
 ** LRU list, then this function is a no-op.
 **
-** The global mutex must be held when this function is called.
+** The PGroup mutex must be held when this function is called.
+**
+** If pPage is NULL then this routine is a no-op.
 */
 static void pcache1PinPage(PgHdr1 *pPage){
-  assert( sqlite3_mutex_held(pcache1.mutex) );
-  if( pPage && (pPage->pLruNext || pPage==pcache1.pLruTail) ){
+  PCache1 *pCache;
+  PGroup *pGroup;
+
+  if( pPage==0 ) return;
+  pCache = pPage->pCache;
+  pGroup = pCache->pGroup;
+  assert( sqlite3_mutex_held(pGroup->mutex) );
+  if( pPage->pLruNext || pPage==pGroup->pLruTail ){
     if( pPage->pLruPrev ){
       pPage->pLruPrev->pLruNext = pPage->pLruNext;
     }
     if( pPage->pLruNext ){
       pPage->pLruNext->pLruPrev = pPage->pLruPrev;
     }
-    if( pcache1.pLruHead==pPage ){
-      pcache1.pLruHead = pPage->pLruNext;
+    if( pGroup->pLruHead==pPage ){
+      pGroup->pLruHead = pPage->pLruNext;
     }
-    if( pcache1.pLruTail==pPage ){
-      pcache1.pLruTail = pPage->pLruPrev;
+    if( pGroup->pLruTail==pPage ){
+      pGroup->pLruTail = pPage->pLruPrev;
     }
     pPage->pLruNext = 0;
     pPage->pLruPrev = 0;
@@ -30081,13 +35737,14 @@ static void pcache1PinPage(PgHdr1 *pPage){
 ** Remove the page supplied as an argument from the hash table 
 ** (PCache1.apHash structure) that it is currently stored in.
 **
-** The global mutex must be held when this function is called.
+** The PGroup mutex must be held when this function is called.
 */
 static void pcache1RemoveFromHash(PgHdr1 *pPage){
   unsigned int h;
   PCache1 *pCache = pPage->pCache;
   PgHdr1 **pp;
 
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
   h = pPage->iKey % pCache->nHash;
   for(pp=&pCache->apHash[h]; (*pp)!=pPage; pp=&(*pp)->pNext);
   *pp = (*pp)->pNext;
@@ -30096,13 +35753,14 @@ static void pcache1RemoveFromHash(PgHdr1 *pPage){
 }
 
 /*
-** If there are currently more than pcache.nMaxPage pages allocated, try
-** to recycle pages to reduce the number allocated to pcache.nMaxPage.
+** If there are currently more than nMaxPage pages allocated, try
+** to recycle pages to reduce the number allocated to nMaxPage.
 */
-static void pcache1EnforceMaxPage(void){
-  assert( sqlite3_mutex_held(pcache1.mutex) );
-  while( pcache1.nCurrentPage>pcache1.nMaxPage && pcache1.pLruTail ){
-    PgHdr1 *p = pcache1.pLruTail;
+static void pcache1EnforceMaxPage(PGroup *pGroup){
+  assert( sqlite3_mutex_held(pGroup->mutex) );
+  while( pGroup->nCurrentPage>pGroup->nMaxPage && pGroup->pLruTail ){
+    PgHdr1 *p = pGroup->pLruTail;
+    assert( p->pCache->pGroup==pGroup );
     pcache1PinPage(p);
     pcache1RemoveFromHash(p);
     pcache1FreePage(p);
@@ -30114,27 +35772,31 @@ static void pcache1EnforceMaxPage(void){
 ** greater than or equal to iLimit. Any pinned pages that meet this 
 ** criteria are unpinned before they are discarded.
 **
-** The global mutex must be held when this function is called.
+** The PCache mutex must be held when this function is called.
 */
 static void pcache1TruncateUnsafe(
-  PCache1 *pCache, 
-  unsigned int iLimit 
+  PCache1 *pCache,             /* The cache to truncate */
+  unsigned int iLimit          /* Drop pages with this pgno or larger */
 ){
+  TESTONLY( unsigned int nPage = 0; )  /* To assert pCache->nPage is correct */
   unsigned int h;
-  assert( sqlite3_mutex_held(pcache1.mutex) );
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
   for(h=0; h<pCache->nHash; h++){
     PgHdr1 **pp = &pCache->apHash[h]; 
     PgHdr1 *pPage;
     while( (pPage = *pp)!=0 ){
       if( pPage->iKey>=iLimit ){
-        pcache1PinPage(pPage);
+        pCache->nPage--;
         *pp = pPage->pNext;
+        pcache1PinPage(pPage);
         pcache1FreePage(pPage);
       }else{
         pp = &pPage->pNext;
+        TESTONLY( nPage++; )
       }
     }
   }
+  assert( pCache->nPage==nPage );
 }
 
 /******************************************************************************/
@@ -30145,19 +35807,26 @@ static void pcache1TruncateUnsafe(
 */
 static int pcache1Init(void *NotUsed){
   UNUSED_PARAMETER(NotUsed);
+  assert( pcache1.isInit==0 );
   memset(&pcache1, 0, sizeof(pcache1));
   if( sqlite3GlobalConfig.bCoreMutex ){
-    pcache1.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU);
+    pcache1.grp.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU);
+    pcache1.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PMEM);
   }
+  pcache1.grp.mxPinned = 10;
+  pcache1.isInit = 1;
   return SQLITE_OK;
 }
 
 /*
 ** Implementation of the sqlite3_pcache.xShutdown method.
+** Note that the static mutex allocated in xInit does 
+** not need to be freed.
 */
 static void pcache1Shutdown(void *NotUsed){
   UNUSED_PARAMETER(NotUsed);
-  /* no-op */
+  assert( pcache1.isInit!=0 );
+  memset(&pcache1, 0, sizeof(pcache1));
 }
 
 /*
@@ -30165,19 +35834,51 @@ static void pcache1Shutdown(void *NotUsed){
 **
 ** Allocate a new cache.
 */
-static sqlite3_pcache *pcache1Create(int szPage, int bPurgeable){
-  PCache1 *pCache;
+static sqlite3_pcache *pcache1Create(int szPage, int szExtra, int bPurgeable){
+  PCache1 *pCache;      /* The newly created page cache */
+  PGroup *pGroup;       /* The group the new page cache will belong to */
+  int sz;               /* Bytes of memory required to allocate the new cache */
 
-  pCache = (PCache1 *)sqlite3_malloc(sizeof(PCache1));
+  /*
+  ** The seperateCache variable is true if each PCache has its own private
+  ** PGroup.  In other words, separateCache is true for mode (1) where no
+  ** mutexing is required.
+  **
+  **   *  Always use a unified cache (mode-2) if ENABLE_MEMORY_MANAGEMENT
+  **
+  **   *  Always use a unified cache in single-threaded applications
+  **
+  **   *  Otherwise (if multi-threaded and ENABLE_MEMORY_MANAGEMENT is off)
+  **      use separate caches (mode-1)
+  */
+#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) || SQLITE_THREADSAFE==0
+  const int separateCache = 0;
+#else
+  int separateCache = sqlite3GlobalConfig.bCoreMutex>0;
+#endif
+
+  assert( (szPage & (szPage-1))==0 && szPage>=512 && szPage<=65536 );
+  assert( szExtra < 300 );
+
+  sz = sizeof(PCache1) + sizeof(PGroup)*separateCache;
+  pCache = (PCache1 *)sqlite3MallocZero(sz);
   if( pCache ){
-    memset(pCache, 0, sizeof(PCache1));
+    if( separateCache ){
+      pGroup = (PGroup*)&pCache[1];
+      pGroup->mxPinned = 10;
+    }else{
+      pGroup = &pcache1.grp;
+    }
+    pCache->pGroup = pGroup;
     pCache->szPage = szPage;
+    pCache->szExtra = szExtra;
     pCache->bPurgeable = (bPurgeable ? 1 : 0);
     if( bPurgeable ){
       pCache->nMin = 10;
-      pcache1EnterMutex();
-      pcache1.nMinPage += pCache->nMin;
-      pcache1LeaveMutex();
+      pcache1EnterMutex(pGroup);
+      pGroup->nMinPage += pCache->nMin;
+      pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+      pcache1LeaveMutex(pGroup);
     }
   }
   return (sqlite3_pcache *)pCache;
@@ -30191,11 +35892,33 @@ static sqlite3_pcache *pcache1Create(int szPage, int bPurgeable){
 static void pcache1Cachesize(sqlite3_pcache *p, int nMax){
   PCache1 *pCache = (PCache1 *)p;
   if( pCache->bPurgeable ){
-    pcache1EnterMutex();
-    pcache1.nMaxPage += (nMax - pCache->nMax);
+    PGroup *pGroup = pCache->pGroup;
+    pcache1EnterMutex(pGroup);
+    pGroup->nMaxPage += (nMax - pCache->nMax);
+    pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
     pCache->nMax = nMax;
-    pcache1EnforceMaxPage();
-    pcache1LeaveMutex();
+    pCache->n90pct = pCache->nMax*9/10;
+    pcache1EnforceMaxPage(pGroup);
+    pcache1LeaveMutex(pGroup);
+  }
+}
+
+/*
+** Implementation of the sqlite3_pcache.xShrink method. 
+**
+** Free up as much memory as possible.
+*/
+static void pcache1Shrink(sqlite3_pcache *p){
+  PCache1 *pCache = (PCache1*)p;
+  if( pCache->bPurgeable ){
+    PGroup *pGroup = pCache->pGroup;
+    int savedMaxPage;
+    pcache1EnterMutex(pGroup);
+    savedMaxPage = pGroup->nMaxPage;
+    pGroup->nMaxPage = 0;
+    pcache1EnforceMaxPage(pGroup);
+    pGroup->nMaxPage = savedMaxPage;
+    pcache1LeaveMutex(pGroup);
   }
 }
 
@@ -30204,9 +35927,10 @@ static void pcache1Cachesize(sqlite3_pcache *p, int nMax){
 */
 static int pcache1Pagecount(sqlite3_pcache *p){
   int n;
-  pcache1EnterMutex();
-  n = ((PCache1 *)p)->nPage;
-  pcache1LeaveMutex();
+  PCache1 *pCache = (PCache1*)p;
+  pcache1EnterMutex(pCache->pGroup);
+  n = pCache->nPage;
+  pcache1LeaveMutex(pCache->pGroup);
   return n;
 }
 
@@ -30216,7 +35940,14 @@ static int pcache1Pagecount(sqlite3_pcache *p){
 ** Fetch a page by key value.
 **
 ** Whether or not a new page may be allocated by this function depends on
-** the value of the createFlag argument.
+** the value of the createFlag argument.  0 means do not allocate a new
+** page.  1 means allocate a new page if space is easily available.  2 
+** means to try really hard to allocate a new page.
+**
+** For a non-purgeable cache (a cache used as the storage for an in-memory
+** database) there is really no difference between createFlag 1 and 2.  So
+** the calling function (pcache.c) will never have a createFlag of 1 on
+** a non-purgeable cache.
 **
 ** There are three different approaches to obtaining space for a page,
 ** depending on the value of parameter createFlag (which may be 0, 1 or 2).
@@ -30227,15 +35958,16 @@ static int pcache1Pagecount(sqlite3_pcache *p){
 **   2. If createFlag==0 and the page is not already in the cache, NULL is
 **      returned.
 **
-**   3. If createFlag is 1, the cache is marked as purgeable and the page is 
-**      not already in the cache, and if either of the following are true, 
-**      return NULL:
+**   3. If createFlag is 1, and the page is not already in the cache, then
+**      return NULL (do not allocate a new page) if any of the following
+**      conditions are true:
 **
 **       (a) the number of pages pinned by the cache is greater than
 **           PCache1.nMax, or
+**
 **       (b) the number of pages pinned by the cache is greater than
 **           the sum of nMax for all purgeable caches, less the sum of 
-**           nMin for all other purgeable caches. 
+**           nMin for all other purgeable caches, or
 **
 **   4. If none of the first three conditions apply and the cache is marked
 **      as purgeable, and if one of the following is true:
@@ -30247,36 +35979,63 @@ static int pcache1Pagecount(sqlite3_pcache *p){
 **           already equal to or greater than the sum of nMax for all
 **           purgeable caches,
 **
+**       (c) The system is under memory pressure and wants to avoid
+**           unnecessary pages cache entry allocations
+**
 **      then attempt to recycle a page from the LRU list. If it is the right
 **      size, return the recycled buffer. Otherwise, free the buffer and
 **      proceed to step 5. 
 **
 **   5. Otherwise, allocate and return a new page buffer.
 */
-static void *pcache1Fetch(sqlite3_pcache *p, unsigned int iKey, int createFlag){
+static sqlite3_pcache_page *pcache1Fetch(
+  sqlite3_pcache *p, 
+  unsigned int iKey, 
+  int createFlag
+){
   unsigned int nPinned;
   PCache1 *pCache = (PCache1 *)p;
+  PGroup *pGroup;
   PgHdr1 *pPage = 0;
 
-  pcache1EnterMutex();
-  if( createFlag==1 ) sqlite3BeginBenignMalloc();
+  assert( pCache->bPurgeable || createFlag!=1 );
+  assert( pCache->bPurgeable || pCache->nMin==0 );
+  assert( pCache->bPurgeable==0 || pCache->nMin==10 );
+  assert( pCache->nMin==0 || pCache->bPurgeable );
+  pcache1EnterMutex(pGroup = pCache->pGroup);
 
-  /* Search the hash table for an existing entry. */
+  /* Step 1: Search the hash table for an existing entry. */
   if( pCache->nHash>0 ){
     unsigned int h = iKey % pCache->nHash;
     for(pPage=pCache->apHash[h]; pPage&&pPage->iKey!=iKey; pPage=pPage->pNext);
   }
 
+  /* Step 2: Abort if no existing page is found and createFlag is 0 */
   if( pPage || createFlag==0 ){
     pcache1PinPage(pPage);
     goto fetch_out;
   }
 
-  /* Step 3 of header comment. */
+  /* The pGroup local variable will normally be initialized by the
+  ** pcache1EnterMutex() macro above.  But if SQLITE_MUTEX_OMIT is defined,
+  ** then pcache1EnterMutex() is a no-op, so we have to initialize the
+  ** local variable here.  Delaying the initialization of pGroup is an
+  ** optimization:  The common case is to exit the module before reaching
+  ** this point.
+  */
+#ifdef SQLITE_MUTEX_OMIT
+  pGroup = pCache->pGroup;
+#endif
+
+  /* Step 3: Abort if createFlag is 1 but the cache is nearly full */
+  assert( pCache->nPage >= pCache->nRecyclable );
   nPinned = pCache->nPage - pCache->nRecyclable;
-  if( createFlag==1 && pCache->bPurgeable && (
-        nPinned>=(pcache1.nMaxPage+pCache->nMin-pcache1.nMinPage)
-     || nPinned>=(pCache->nMax)
+  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
+  assert( pCache->n90pct == pCache->nMax*9/10 );
+  if( createFlag==1 && (
+        nPinned>=pGroup->mxPinned
+     || nPinned>=pCache->n90pct
+     || pcache1UnderMemoryPressure(pCache)
   )){
     goto fetch_out;
   }
@@ -30285,18 +36044,30 @@ static void *pcache1Fetch(sqlite3_pcache *p, unsigned int iKey, int createFlag){
     goto fetch_out;
   }
 
-  /* Step 4. Try to recycle a page buffer if appropriate. */
-  if( pCache->bPurgeable && pcache1.pLruTail && (
-      pCache->nPage>=pCache->nMax-1 || pcache1.nCurrentPage>=pcache1.nMaxPage
+  /* Step 4. Try to recycle a page. */
+  if( pCache->bPurgeable && pGroup->pLruTail && (
+         (pCache->nPage+1>=pCache->nMax)
+      || pGroup->nCurrentPage>=pGroup->nMaxPage
+      || pcache1UnderMemoryPressure(pCache)
   )){
-    pPage = pcache1.pLruTail;
+    PCache1 *pOther;
+    pPage = pGroup->pLruTail;
     pcache1RemoveFromHash(pPage);
     pcache1PinPage(pPage);
-    if( pPage->pCache->szPage!=pCache->szPage ){
+    pOther = pPage->pCache;
+
+    /* We want to verify that szPage and szExtra are the same for pOther
+    ** and pCache.  Assert that we can verify this by comparing sums. */
+    assert( (pCache->szPage & (pCache->szPage-1))==0 && pCache->szPage>=512 );
+    assert( pCache->szExtra<512 );
+    assert( (pOther->szPage & (pOther->szPage-1))==0 && pOther->szPage>=512 );
+    assert( pOther->szExtra<512 );
+
+    if( pOther->szPage+pOther->szExtra != pCache->szPage+pCache->szExtra ){
       pcache1FreePage(pPage);
       pPage = 0;
     }else{
-      pcache1.nCurrentPage -= (pPage->pCache->bPurgeable - pCache->bPurgeable);
+      pGroup->nCurrentPage -= (pOther->bPurgeable - pCache->bPurgeable);
     }
   }
 
@@ -30304,16 +36075,20 @@ static void *pcache1Fetch(sqlite3_pcache *p, unsigned int iKey, int createFlag){
   ** attempt to allocate a new one. 
   */
   if( !pPage ){
+    if( createFlag==1 ) sqlite3BeginBenignMalloc();
     pPage = pcache1AllocPage(pCache);
+    if( createFlag==1 ) sqlite3EndBenignMalloc();
   }
 
   if( pPage ){
     unsigned int h = iKey % pCache->nHash;
-    memset(pPage, 0, pCache->szPage + sizeof(PgHdr1));
     pCache->nPage++;
     pPage->iKey = iKey;
     pPage->pNext = pCache->apHash[h];
     pPage->pCache = pCache;
+    pPage->pLruPrev = 0;
+    pPage->pLruNext = 0;
+    *(void **)pPage->page.pExtra = 0;
     pCache->apHash[h] = pPage;
   }
 
@@ -30321,9 +36096,8 @@ fetch_out:
   if( pPage && iKey>pCache->iMaxKey ){
     pCache->iMaxKey = iKey;
   }
-  if( createFlag==1 ) sqlite3EndBenignMalloc();
-  pcache1LeaveMutex();
-  return (pPage ? PGHDR1_TO_PAGE(pPage) : 0);
+  pcache1LeaveMutex(pGroup);
+  return &pPage->page;
 }
 
 
@@ -30332,39 +36106,41 @@ fetch_out:
 **
 ** Mark a page as unpinned (eligible for asynchronous recycling).
 */
-static void pcache1Unpin(sqlite3_pcache *p, void *pPg, int reuseUnlikely){
+static void pcache1Unpin(
+  sqlite3_pcache *p, 
+  sqlite3_pcache_page *pPg, 
+  int reuseUnlikely
+){
   PCache1 *pCache = (PCache1 *)p;
-  PgHdr1 *pPage = PAGE_TO_PGHDR1(pPg);
-
-  pcache1EnterMutex();
+  PgHdr1 *pPage = (PgHdr1 *)pPg;
+  PGroup *pGroup = pCache->pGroup;
+ 
+  assert( pPage->pCache==pCache );
+  pcache1EnterMutex(pGroup);
 
   /* It is an error to call this function if the page is already 
-  ** part of the global LRU list.
+  ** part of the PGroup LRU list.
   */
   assert( pPage->pLruPrev==0 && pPage->pLruNext==0 );
-  assert( pcache1.pLruHead!=pPage && pcache1.pLruTail!=pPage );
+  assert( pGroup->pLruHead!=pPage && pGroup->pLruTail!=pPage );
 
-  if( reuseUnlikely || pcache1.nCurrentPage>pcache1.nMaxPage ){
+  if( reuseUnlikely || pGroup->nCurrentPage>pGroup->nMaxPage ){
     pcache1RemoveFromHash(pPage);
     pcache1FreePage(pPage);
   }else{
-    /* Add the page to the global LRU list. Normally, the page is added to
-    ** the head of the list (last page to be recycled). However, if the 
-    ** reuseUnlikely flag passed to this function is true, the page is added
-    ** to the tail of the list (first page to be recycled).
-    */
-    if( pcache1.pLruHead ){
-      pcache1.pLruHead->pLruPrev = pPage;
-      pPage->pLruNext = pcache1.pLruHead;
-      pcache1.pLruHead = pPage;
+    /* Add the page to the PGroup LRU list. */
+    if( pGroup->pLruHead ){
+      pGroup->pLruHead->pLruPrev = pPage;
+      pPage->pLruNext = pGroup->pLruHead;
+      pGroup->pLruHead = pPage;
     }else{
-      pcache1.pLruTail = pPage;
-      pcache1.pLruHead = pPage;
+      pGroup->pLruTail = pPage;
+      pGroup->pLruHead = pPage;
     }
     pCache->nRecyclable++;
   }
 
-  pcache1LeaveMutex();
+  pcache1LeaveMutex(pCache->pGroup);
 }
 
 /*
@@ -30372,17 +36148,18 @@ static void pcache1Unpin(sqlite3_pcache *p, void *pPg, int reuseUnlikely){
 */
 static void pcache1Rekey(
   sqlite3_pcache *p,
-  void *pPg,
+  sqlite3_pcache_page *pPg,
   unsigned int iOld,
   unsigned int iNew
 ){
   PCache1 *pCache = (PCache1 *)p;
-  PgHdr1 *pPage = PAGE_TO_PGHDR1(pPg);
+  PgHdr1 *pPage = (PgHdr1 *)pPg;
   PgHdr1 **pp;
   unsigned int h; 
   assert( pPage->iKey==iOld );
+  assert( pPage->pCache==pCache );
 
-  pcache1EnterMutex();
+  pcache1EnterMutex(pCache->pGroup);
 
   h = iOld%pCache->nHash;
   pp = &pCache->apHash[h];
@@ -30395,12 +36172,11 @@ static void pcache1Rekey(
   pPage->iKey = iNew;
   pPage->pNext = pCache->apHash[h];
   pCache->apHash[h] = pPage;
-
   if( iNew>pCache->iMaxKey ){
     pCache->iMaxKey = iNew;
   }
 
-  pcache1LeaveMutex();
+  pcache1LeaveMutex(pCache->pGroup);
 }
 
 /*
@@ -30412,12 +36188,12 @@ static void pcache1Rekey(
 */
 static void pcache1Truncate(sqlite3_pcache *p, unsigned int iLimit){
   PCache1 *pCache = (PCache1 *)p;
-  pcache1EnterMutex();
+  pcache1EnterMutex(pCache->pGroup);
   if( iLimit<=pCache->iMaxKey ){
     pcache1TruncateUnsafe(pCache, iLimit);
     pCache->iMaxKey = iLimit-1;
   }
-  pcache1LeaveMutex();
+  pcache1LeaveMutex(pCache->pGroup);
 }
 
 /*
@@ -30427,12 +36203,17 @@ static void pcache1Truncate(sqlite3_pcache *p, unsigned int iLimit){
 */
 static void pcache1Destroy(sqlite3_pcache *p){
   PCache1 *pCache = (PCache1 *)p;
-  pcache1EnterMutex();
+  PGroup *pGroup = pCache->pGroup;
+  assert( pCache->bPurgeable || (pCache->nMax==0 && pCache->nMin==0) );
+  pcache1EnterMutex(pGroup);
   pcache1TruncateUnsafe(pCache, 0);
-  pcache1.nMaxPage -= pCache->nMax;
-  pcache1.nMinPage -= pCache->nMin;
-  pcache1EnforceMaxPage();
-  pcache1LeaveMutex();
+  assert( pGroup->nMaxPage >= pCache->nMax );
+  pGroup->nMaxPage -= pCache->nMax;
+  assert( pGroup->nMinPage >= pCache->nMin );
+  pGroup->nMinPage -= pCache->nMin;
+  pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+  pcache1EnforceMaxPage(pGroup);
+  pcache1LeaveMutex(pGroup);
   sqlite3_free(pCache->apHash);
   sqlite3_free(pCache);
 }
@@ -30443,7 +36224,8 @@ static void pcache1Destroy(sqlite3_pcache *p){
 ** already provided an alternative.
 */
 SQLITE_PRIVATE void sqlite3PCacheSetDefault(void){
-  static sqlite3_pcache_methods defaultMethods = {
+  static const sqlite3_pcache_methods2 defaultMethods = {
+    1,                       /* iVersion */
     0,                       /* pArg */
     pcache1Init,             /* xInit */
     pcache1Shutdown,         /* xShutdown */
@@ -30454,9 +36236,10 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void){
     pcache1Unpin,            /* xUnpin */
     pcache1Rekey,            /* xRekey */
     pcache1Truncate,         /* xTruncate */
-    pcache1Destroy           /* xDestroy */
+    pcache1Destroy,          /* xDestroy */
+    pcache1Shrink            /* xShrink */
   };
-  sqlite3_config(SQLITE_CONFIG_PCACHE, &defaultMethods);
+  sqlite3_config(SQLITE_CONFIG_PCACHE2, &defaultMethods);
 }
 
 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
@@ -30471,16 +36254,21 @@ SQLITE_PRIVATE void sqlite3PCacheSetDefault(void){
 */
 SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int nReq){
   int nFree = 0;
+  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
+  assert( sqlite3_mutex_notheld(pcache1.mutex) );
   if( pcache1.pStart==0 ){
     PgHdr1 *p;
-    pcache1EnterMutex();
-    while( (nReq<0 || nFree<nReq) && (p=pcache1.pLruTail) ){
-      nFree += sqlite3MallocSize(p);
+    pcache1EnterMutex(&pcache1.grp);
+    while( (nReq<0 || nFree<nReq) && ((p=pcache1.grp.pLruTail)!=0) ){
+      nFree += pcache1MemSize(p->page.pBuf);
+#ifdef SQLITE_PCACHE_SEPARATE_HEADER
+      nFree += sqlite3MemSize(p);
+#endif
       pcache1PinPage(p);
       pcache1RemoveFromHash(p);
       pcache1FreePage(p);
     }
-    pcache1LeaveMutex();
+    pcache1LeaveMutex(&pcache1.grp);
   }
   return nFree;
 }
@@ -30499,12 +36287,12 @@ SQLITE_PRIVATE void sqlite3PcacheStats(
 ){
   PgHdr1 *p;
   int nRecyclable = 0;
-  for(p=pcache1.pLruHead; p; p=p->pLruNext){
+  for(p=pcache1.grp.pLruHead; p; p=p->pLruNext){
     nRecyclable++;
   }
-  *pnCurrent = pcache1.nCurrentPage;
-  *pnMax = pcache1.nMaxPage;
-  *pnMin = pcache1.nMinPage;
+  *pnCurrent = pcache1.grp.nCurrentPage;
+  *pnMax = (int)pcache1.grp.nMaxPage;
+  *pnMin = (int)pcache1.grp.nMinPage;
   *pnRecyclable = nRecyclable;
 }
 #endif
@@ -30523,46 +36311,91 @@ SQLITE_PRIVATE void sqlite3PcacheStats(
 **
 *************************************************************************
 **
-** This module implements an object we call a "Row Set".
+** This module implements an object we call a "RowSet".
 **
-** The RowSet object is a bag of rowids.  Rowids
-** are inserted into the bag in an arbitrary order.  Then they are
-** pulled from the bag in sorted order.  Rowids only appear in the
-** bag once.  If the same rowid is inserted multiple times, the
-** second and subsequent inserts make no difference on the output.
+** The RowSet object is a collection of rowids.  Rowids
+** are inserted into the RowSet in an arbitrary order.  Inserts
+** can be intermixed with tests to see if a given rowid has been
+** previously inserted into the RowSet.
 **
-** This implementation accumulates rowids in a linked list.  For
-** output, it first sorts the linked list (removing duplicates during
-** the sort) then returns elements one by one by walking the list.
+** After all inserts are finished, it is possible to extract the
+** elements of the RowSet in sorted order.  Once this extraction
+** process has started, no new elements may be inserted.
 **
-** Big chunks of rowid/next-ptr pairs are allocated at a time, to
-** reduce the malloc overhead.
+** Hence, the primitive operations for a RowSet are:
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+**    CREATE
+**    INSERT
+**    TEST
+**    SMALLEST
+**    DESTROY
+**
+** The CREATE and DESTROY primitives are the constructor and destructor,
+** obviously.  The INSERT primitive adds a new element to the RowSet.
+** TEST checks to see if an element is already in the RowSet.  SMALLEST
+** extracts the least value from the RowSet.
+**
+** The INSERT primitive might allocate additional memory.  Memory is
+** allocated in chunks so most INSERTs do no allocation.  There is an 
+** upper bound on the size of allocated memory.  No memory is freed
+** until DESTROY.
+**
+** The TEST primitive includes a "batch" number.  The TEST primitive
+** will only see elements that were inserted before the last change
+** in the batch number.  In other words, if an INSERT occurs between
+** two TESTs where the TESTs have the same batch nubmer, then the
+** value added by the INSERT will not be visible to the second TEST.
+** The initial batch number is zero, so if the very first TEST contains
+** a non-zero batch number, it will see all prior INSERTs.
+**
+** No INSERTs may occurs after a SMALLEST.  An assertion will fail if
+** that is attempted.
+**
+** The cost of an INSERT is roughly constant.  (Sometime new memory
+** has to be allocated on an INSERT.)  The cost of a TEST with a new
+** batch number is O(NlogN) where N is the number of elements in the RowSet.
+** The cost of a TEST using the same batch number is O(logN).  The cost
+** of the first SMALLEST is O(NlogN).  Second and subsequent SMALLEST
+** primitives are constant time.  The cost of DESTROY is O(N).
+**
+** There is an added cost of O(N) when switching between TEST and
+** SMALLEST primitives.
 */
 
+
+/*
+** Target size for allocation chunks.
+*/
+#define ROWSET_ALLOCATION_SIZE 1024
+
 /*
 ** The number of rowset entries per allocation chunk.
 */
-#define ROWSET_ENTRY_PER_CHUNK  63
+#define ROWSET_ENTRY_PER_CHUNK  \
+                       ((ROWSET_ALLOCATION_SIZE-8)/sizeof(struct RowSetEntry))
 
 /*
-** Each entry in a RowSet is an instance of the following
-** structure:
+** Each entry in a RowSet is an instance of the following object.
+**
+** This same object is reused to store a linked list of trees of RowSetEntry
+** objects.  In that alternative use, pRight points to the next entry
+** in the list, pLeft points to the tree, and v is unused.  The
+** RowSet.pForest value points to the head of this forest list.
 */
 struct RowSetEntry {            
   i64 v;                        /* ROWID value for this entry */
-  struct RowSetEntry *pNext;    /* Next entry on a list of all entries */
+  struct RowSetEntry *pRight;   /* Right subtree (larger entries) or list */
+  struct RowSetEntry *pLeft;    /* Left subtree (smaller entries) */
 };
 
 /*
-** Index entries are allocated in large chunks (instances of the
+** RowSetEntry objects are allocated in large chunks (instances of the
 ** following structure) to reduce memory allocation overhead.  The
 ** chunks are kept on a linked list so that they can be deallocated
 ** when the RowSet is destroyed.
 */
 struct RowSetChunk {
-  struct RowSetChunk *pNext;             /* Next chunk on list of them all */
+  struct RowSetChunk *pNextChunk;        /* Next chunk on list of them all */
   struct RowSetEntry aEntry[ROWSET_ENTRY_PER_CHUNK]; /* Allocated entries */
 };
 
@@ -30574,13 +36407,21 @@ struct RowSetChunk {
 struct RowSet {
   struct RowSetChunk *pChunk;    /* List of all chunk allocations */
   sqlite3 *db;                   /* The database connection */
-  struct RowSetEntry *pEntry;    /* List of entries in the rowset */
+  struct RowSetEntry *pEntry;    /* List of entries using pRight */
   struct RowSetEntry *pLast;     /* Last entry on the pEntry list */
   struct RowSetEntry *pFresh;    /* Source of new entry objects */
+  struct RowSetEntry *pForest;   /* List of binary trees of entries */
   u16 nFresh;                    /* Number of objects on pFresh */
-  u8 isSorted;                   /* True if content is sorted */
+  u8 rsFlags;                    /* Various flags */
+  u8 iBatch;                     /* Current insert batch */
 };
 
+/*
+** Allowed values for RowSet.rsFlags
+*/
+#define ROWSET_SORTED  0x01   /* True if RowSet.pEntry is sorted */
+#define ROWSET_NEXT    0x02   /* True if sqlite3RowSetNext() has been called */
+
 /*
 ** Turn bulk memory into a RowSet object.  N bytes of memory
 ** are available at pSpace.  The db pointer is used as a memory context
@@ -30595,32 +36436,62 @@ struct RowSet {
 */
 SQLITE_PRIVATE RowSet *sqlite3RowSetInit(sqlite3 *db, void *pSpace, unsigned int N){
   RowSet *p;
-  assert( N >= sizeof(*p) );
+  assert( N >= ROUND8(sizeof(*p)) );
   p = pSpace;
   p->pChunk = 0;
   p->db = db;
   p->pEntry = 0;
   p->pLast = 0;
-  p->pFresh = (struct RowSetEntry*)&p[1];
-  p->nFresh = (u16)((N - sizeof(*p))/sizeof(struct RowSetEntry));
-  p->isSorted = 1;
+  p->pForest = 0;
+  p->pFresh = (struct RowSetEntry*)(ROUND8(sizeof(*p)) + (char*)p);
+  p->nFresh = (u16)((N - ROUND8(sizeof(*p)))/sizeof(struct RowSetEntry));
+  p->rsFlags = ROWSET_SORTED;
+  p->iBatch = 0;
   return p;
 }
 
 /*
-** Deallocate all chunks from a RowSet.
+** Deallocate all chunks from a RowSet.  This frees all memory that
+** the RowSet has allocated over its lifetime.  This routine is
+** the destructor for the RowSet.
 */
 SQLITE_PRIVATE void sqlite3RowSetClear(RowSet *p){
   struct RowSetChunk *pChunk, *pNextChunk;
   for(pChunk=p->pChunk; pChunk; pChunk = pNextChunk){
-    pNextChunk = pChunk->pNext;
+    pNextChunk = pChunk->pNextChunk;
     sqlite3DbFree(p->db, pChunk);
   }
   p->pChunk = 0;
   p->nFresh = 0;
   p->pEntry = 0;
   p->pLast = 0;
-  p->isSorted = 1;
+  p->pForest = 0;
+  p->rsFlags = ROWSET_SORTED;
+}
+
+/*
+** Allocate a new RowSetEntry object that is associated with the
+** given RowSet.  Return a pointer to the new and completely uninitialized
+** objected.
+**
+** In an OOM situation, the RowSet.db->mallocFailed flag is set and this
+** routine returns NULL.
+*/
+static struct RowSetEntry *rowSetEntryAlloc(RowSet *p){
+  assert( p!=0 );
+  if( p->nFresh==0 ){
+    struct RowSetChunk *pNew;
+    pNew = sqlite3DbMallocRaw(p->db, sizeof(*pNew));
+    if( pNew==0 ){
+      return 0;
+    }
+    pNew->pNextChunk = p->pChunk;
+    p->pChunk = pNew;
+    p->pFresh = pNew->aEntry;
+    p->nFresh = ROWSET_ENTRY_PER_CHUNK;
+  }
+  p->nFresh--;
+  return p->pFresh++;
 }
 
 /*
@@ -30630,43 +36501,35 @@ SQLITE_PRIVATE void sqlite3RowSetClear(RowSet *p){
 ** memory allocation fails.
 */
 SQLITE_PRIVATE void sqlite3RowSetInsert(RowSet *p, i64 rowid){
-  struct RowSetEntry *pEntry;
-  struct RowSetEntry *pLast;
-  if( p==0 ) return;  /* Must have been a malloc failure */
-  if( p->nFresh==0 ){
-    struct RowSetChunk *pNew;
-    pNew = sqlite3DbMallocRaw(p->db, sizeof(*pNew));
-    if( pNew==0 ){
-      return;
-    }
-    pNew->pNext = p->pChunk;
-    p->pChunk = pNew;
-    p->pFresh = pNew->aEntry;
-    p->nFresh = ROWSET_ENTRY_PER_CHUNK;
-  }
-  pEntry = p->pFresh++;
-  p->nFresh--;
+  struct RowSetEntry *pEntry;  /* The new entry */
+  struct RowSetEntry *pLast;   /* The last prior entry */
+
+  /* This routine is never called after sqlite3RowSetNext() */
+  assert( p!=0 && (p->rsFlags & ROWSET_NEXT)==0 );
+
+  pEntry = rowSetEntryAlloc(p);
+  if( pEntry==0 ) return;
   pEntry->v = rowid;
-  pEntry->pNext = 0;
+  pEntry->pRight = 0;
   pLast = p->pLast;
   if( pLast ){
-    if( p->isSorted && rowid<=pLast->v ){
-      p->isSorted = 0;
+    if( (p->rsFlags & ROWSET_SORTED)!=0 && rowid<=pLast->v ){
+      p->rsFlags &= ~ROWSET_SORTED;
     }
-    pLast->pNext = pEntry;
+    pLast->pRight = pEntry;
   }else{
-    assert( p->pEntry==0 );
     p->pEntry = pEntry;
   }
   p->pLast = pEntry;
 }
 
 /*
-** Merge two lists of RowSet entries.  Remove duplicates.
+** Merge two lists of RowSetEntry objects.  Remove duplicates.
 **
-** The input lists are assumed to be in sorted order.
+** The input lists are connected via pRight pointers and are 
+** assumed to each already be in sorted order.
 */
-static struct RowSetEntry *boolidxMerge(
+static struct RowSetEntry *rowSetEntryMerge(
   struct RowSetEntry *pA,    /* First sorted list to be merged */
   struct RowSetEntry *pB     /* Second sorted list to be merged */
 ){
@@ -30675,71 +36538,198 @@ static struct RowSetEntry *boolidxMerge(
 
   pTail = &head;
   while( pA && pB ){
-    assert( pA->pNext==0 || pA->v<=pA->pNext->v );
-    assert( pB->pNext==0 || pB->v<=pB->pNext->v );
+    assert( pA->pRight==0 || pA->v<=pA->pRight->v );
+    assert( pB->pRight==0 || pB->v<=pB->pRight->v );
     if( pA->v<pB->v ){
-      pTail->pNext = pA;
-      pA = pA->pNext;
-      pTail = pTail->pNext;
+      pTail->pRight = pA;
+      pA = pA->pRight;
+      pTail = pTail->pRight;
     }else if( pB->v<pA->v ){
-      pTail->pNext = pB;
-      pB = pB->pNext;
-      pTail = pTail->pNext;
+      pTail->pRight = pB;
+      pB = pB->pRight;
+      pTail = pTail->pRight;
     }else{
-      pA = pA->pNext;
+      pA = pA->pRight;
     }
   }
   if( pA ){
-    assert( pA->pNext==0 || pA->v<=pA->pNext->v );
-    pTail->pNext = pA;
+    assert( pA->pRight==0 || pA->v<=pA->pRight->v );
+    pTail->pRight = pA;
   }else{
-    assert( pB==0 || pB->pNext==0 || pB->v<=pB->pNext->v );
-    pTail->pNext = pB;
+    assert( pB==0 || pB->pRight==0 || pB->v<=pB->pRight->v );
+    pTail->pRight = pB;
   }
-  return head.pNext;
+  return head.pRight;
 }
 
 /*
-** Sort all elements of the RowSet into ascending order.
+** Sort all elements on the list of RowSetEntry objects into order of
+** increasing v.
 */ 
-static void sqlite3RowSetSort(RowSet *p){
+static struct RowSetEntry *rowSetEntrySort(struct RowSetEntry *pIn){
   unsigned int i;
-  struct RowSetEntry *pEntry;
-  struct RowSetEntry *aBucket[40];
+  struct RowSetEntry *pNext, *aBucket[40];
 
-  assert( p->isSorted==0 );
   memset(aBucket, 0, sizeof(aBucket));
-  while( p->pEntry ){
-    pEntry = p->pEntry;
-    p->pEntry = pEntry->pNext;
-    pEntry->pNext = 0;
+  while( pIn ){
+    pNext = pIn->pRight;
+    pIn->pRight = 0;
     for(i=0; aBucket[i]; i++){
-      pEntry = boolidxMerge(aBucket[i],pEntry);
+      pIn = rowSetEntryMerge(aBucket[i], pIn);
       aBucket[i] = 0;
     }
-    aBucket[i] = pEntry;
+    aBucket[i] = pIn;
+    pIn = pNext;
   }
-  pEntry = 0;
+  pIn = 0;
   for(i=0; i<sizeof(aBucket)/sizeof(aBucket[0]); i++){
-    pEntry = boolidxMerge(pEntry,aBucket[i]);
+    pIn = rowSetEntryMerge(pIn, aBucket[i]);
   }
-  p->pEntry = pEntry;
-  p->pLast = 0;
-  p->isSorted = 1;
+  return pIn;
+}
+
+
+/*
+** The input, pIn, is a binary tree (or subtree) of RowSetEntry objects.
+** Convert this tree into a linked list connected by the pRight pointers
+** and return pointers to the first and last elements of the new list.
+*/
+static void rowSetTreeToList(
+  struct RowSetEntry *pIn,         /* Root of the input tree */
+  struct RowSetEntry **ppFirst,    /* Write head of the output list here */
+  struct RowSetEntry **ppLast      /* Write tail of the output list here */
+){
+  assert( pIn!=0 );
+  if( pIn->pLeft ){
+    struct RowSetEntry *p;
+    rowSetTreeToList(pIn->pLeft, ppFirst, &p);
+    p->pRight = pIn;
+  }else{
+    *ppFirst = pIn;
+  }
+  if( pIn->pRight ){
+    rowSetTreeToList(pIn->pRight, &pIn->pRight, ppLast);
+  }else{
+    *ppLast = pIn;
+  }
+  assert( (*ppLast)->pRight==0 );
+}
+
+
+/*
+** Convert a sorted list of elements (connected by pRight) into a binary
+** tree with depth of iDepth.  A depth of 1 means the tree contains a single
+** node taken from the head of *ppList.  A depth of 2 means a tree with
+** three nodes.  And so forth.
+**
+** Use as many entries from the input list as required and update the
+** *ppList to point to the unused elements of the list.  If the input
+** list contains too few elements, then construct an incomplete tree
+** and leave *ppList set to NULL.
+**
+** Return a pointer to the root of the constructed binary tree.
+*/
+static struct RowSetEntry *rowSetNDeepTree(
+  struct RowSetEntry **ppList,
+  int iDepth
+){
+  struct RowSetEntry *p;         /* Root of the new tree */
+  struct RowSetEntry *pLeft;     /* Left subtree */
+  if( *ppList==0 ){
+    return 0;
+  }
+  if( iDepth==1 ){
+    p = *ppList;
+    *ppList = p->pRight;
+    p->pLeft = p->pRight = 0;
+    return p;
+  }
+  pLeft = rowSetNDeepTree(ppList, iDepth-1);
+  p = *ppList;
+  if( p==0 ){
+    return pLeft;
+  }
+  p->pLeft = pLeft;
+  *ppList = p->pRight;
+  p->pRight = rowSetNDeepTree(ppList, iDepth-1);
+  return p;
 }
 
 /*
-** Extract the next (smallest) element from the RowSet.
+** Convert a sorted list of elements into a binary tree. Make the tree
+** as deep as it needs to be in order to contain the entire list.
+*/
+static struct RowSetEntry *rowSetListToTree(struct RowSetEntry *pList){
+  int iDepth;           /* Depth of the tree so far */
+  struct RowSetEntry *p;       /* Current tree root */
+  struct RowSetEntry *pLeft;   /* Left subtree */
+
+  assert( pList!=0 );
+  p = pList;
+  pList = p->pRight;
+  p->pLeft = p->pRight = 0;
+  for(iDepth=1; pList; iDepth++){
+    pLeft = p;
+    p = pList;
+    pList = p->pRight;
+    p->pLeft = pLeft;
+    p->pRight = rowSetNDeepTree(&pList, iDepth);
+  }
+  return p;
+}
+
+/*
+** Take all the entries on p->pEntry and on the trees in p->pForest and
+** sort them all together into one big ordered list on p->pEntry.
+**
+** This routine should only be called once in the life of a RowSet.
+*/
+static void rowSetToList(RowSet *p){
+
+  /* This routine is called only once */
+  assert( p!=0 && (p->rsFlags & ROWSET_NEXT)==0 );
+
+  if( (p->rsFlags & ROWSET_SORTED)==0 ){
+    p->pEntry = rowSetEntrySort(p->pEntry);
+  }
+
+  /* While this module could theoretically support it, sqlite3RowSetNext()
+  ** is never called after sqlite3RowSetText() for the same RowSet.  So
+  ** there is never a forest to deal with.  Should this change, simply
+  ** remove the assert() and the #if 0. */
+  assert( p->pForest==0 );
+#if 0
+  while( p->pForest ){
+    struct RowSetEntry *pTree = p->pForest->pLeft;
+    if( pTree ){
+      struct RowSetEntry *pHead, *pTail;
+      rowSetTreeToList(pTree, &pHead, &pTail);
+      p->pEntry = rowSetEntryMerge(p->pEntry, pHead);
+    }
+    p->pForest = p->pForest->pRight;
+  }
+#endif
+  p->rsFlags |= ROWSET_NEXT;  /* Verify this routine is never called again */
+}
+
+/*
+** Extract the smallest element from the RowSet.
 ** Write the element into *pRowid.  Return 1 on success.  Return
 ** 0 if the RowSet is already empty.
+**
+** After this routine has been called, the sqlite3RowSetInsert()
+** routine may not be called again.  
 */
 SQLITE_PRIVATE int sqlite3RowSetNext(RowSet *p, i64 *pRowid){
-  if( !p->isSorted ){
-    sqlite3RowSetSort(p);
-  }
+  assert( p!=0 );
+
+  /* Merge the forest into a single sorted list on first call */
+  if( (p->rsFlags & ROWSET_NEXT)==0 ) rowSetToList(p);
+
+  /* Return the next entry on the list */
   if( p->pEntry ){
     *pRowid = p->pEntry->v;
-    p->pEntry = p->pEntry->pNext;
+    p->pEntry = p->pEntry->pRight;
     if( p->pEntry==0 ){
       sqlite3RowSetClear(p);
     }
@@ -30749,6 +36739,74 @@ SQLITE_PRIVATE int sqlite3RowSetNext(RowSet *p, i64 *pRowid){
   }
 }
 
+/*
+** Check to see if element iRowid was inserted into the rowset as
+** part of any insert batch prior to iBatch.  Return 1 or 0.
+**
+** If this is the first test of a new batch and if there exist entires
+** on pRowSet->pEntry, then sort those entires into the forest at
+** pRowSet->pForest so that they can be tested.
+*/
+SQLITE_PRIVATE int sqlite3RowSetTest(RowSet *pRowSet, u8 iBatch, sqlite3_int64 iRowid){
+  struct RowSetEntry *p, *pTree;
+
+  /* This routine is never called after sqlite3RowSetNext() */
+  assert( pRowSet!=0 && (pRowSet->rsFlags & ROWSET_NEXT)==0 );
+
+  /* Sort entries into the forest on the first test of a new batch 
+  */
+  if( iBatch!=pRowSet->iBatch ){
+    p = pRowSet->pEntry;
+    if( p ){
+      struct RowSetEntry **ppPrevTree = &pRowSet->pForest;
+      if( (pRowSet->rsFlags & ROWSET_SORTED)==0 ){
+        p = rowSetEntrySort(p);
+      }
+      for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
+        ppPrevTree = &pTree->pRight;
+        if( pTree->pLeft==0 ){
+          pTree->pLeft = rowSetListToTree(p);
+          break;
+        }else{
+          struct RowSetEntry *pAux, *pTail;
+          rowSetTreeToList(pTree->pLeft, &pAux, &pTail);
+          pTree->pLeft = 0;
+          p = rowSetEntryMerge(pAux, p);
+        }
+      }
+      if( pTree==0 ){
+        *ppPrevTree = pTree = rowSetEntryAlloc(pRowSet);
+        if( pTree ){
+          pTree->v = 0;
+          pTree->pRight = 0;
+          pTree->pLeft = rowSetListToTree(p);
+        }
+      }
+      pRowSet->pEntry = 0;
+      pRowSet->pLast = 0;
+      pRowSet->rsFlags |= ROWSET_SORTED;
+    }
+    pRowSet->iBatch = iBatch;
+  }
+
+  /* Test to see if the iRowid value appears anywhere in the forest.
+  ** Return 1 if it does and 0 if not.
+  */
+  for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
+    p = pTree->pLeft;
+    while( p ){
+      if( p->v<iRowid ){
+        p = p->pRight;
+      }else if( p->v>iRowid ){
+        p = p->pLeft;
+      }else{
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
 /************** End of rowset.c **********************************************/
 /************** Begin file pager.c *******************************************/
 /*
@@ -30770,10 +36828,235 @@ SQLITE_PRIVATE int sqlite3RowSetNext(RowSet *p, i64 *pRowid){
 ** locking to prevent two processes from writing the same database
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
+/************** Include wal.h in the middle of pager.c ***********************/
+/************** Begin file wal.h *********************************************/
+/*
+** 2010 February 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface to the write-ahead logging 
+** system. Refer to the comments below and the header comment attached to 
+** the implementation of each function in log.c for further details.
+*/
+
+#ifndef _WAL_H_
+#define _WAL_H_
+
+
+/* Additional values that can be added to the sync_flags argument of
+** sqlite3WalFrames():
+*/
+#define WAL_SYNC_TRANSACTIONS  0x20   /* Sync at the end of each transaction */
+#define SQLITE_SYNC_MASK       0x13   /* Mask off the SQLITE_SYNC_* values */
+
+#ifdef SQLITE_OMIT_WAL
+# define sqlite3WalOpen(x,y,z)                   0
+# define sqlite3WalLimit(x,y)
+# define sqlite3WalClose(w,x,y,z)                0
+# define sqlite3WalBeginReadTransaction(y,z)     0
+# define sqlite3WalEndReadTransaction(z)
+# define sqlite3WalRead(v,w,x,y,z)               0
+# define sqlite3WalDbsize(y)                     0
+# define sqlite3WalBeginWriteTransaction(y)      0
+# define sqlite3WalEndWriteTransaction(x)        0
+# define sqlite3WalUndo(x,y,z)                   0
+# define sqlite3WalSavepoint(y,z)
+# define sqlite3WalSavepointUndo(y,z)            0
+# define sqlite3WalFrames(u,v,w,x,y,z)           0
+# define sqlite3WalCheckpoint(r,s,t,u,v,w,x,y,z) 0
+# define sqlite3WalCallback(z)                   0
+# define sqlite3WalExclusiveMode(y,z)            0
+# define sqlite3WalHeapMemory(z)                 0
+# define sqlite3WalFramesize(z)                  0
+#else
+
+#define WAL_SAVEPOINT_NDATA 4
+
+/* Connection to a write-ahead log (WAL) file. 
+** There is one object of this type for each pager. 
+*/
+typedef struct Wal Wal;
+
+/* Open and close a connection to a write-ahead log. */
+SQLITE_PRIVATE int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *, int, i64, Wal**);
+SQLITE_PRIVATE int sqlite3WalClose(Wal *pWal, int sync_flags, int, u8 *);
+
+/* Set the limiting size of a WAL file. */
+SQLITE_PRIVATE void sqlite3WalLimit(Wal*, i64);
+
+/* Used by readers to open (lock) and close (unlock) a snapshot.  A 
+** snapshot is like a read-transaction.  It is the state of the database
+** at an instant in time.  sqlite3WalOpenSnapshot gets a read lock and
+** preserves the current state even if the other threads or processes
+** write to or checkpoint the WAL.  sqlite3WalCloseSnapshot() closes the
+** transaction and releases the lock.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginReadTransaction(Wal *pWal, int *);
+SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal);
+
+/* Read a page from the write-ahead log, if it is present. */
+SQLITE_PRIVATE int sqlite3WalRead(Wal *pWal, Pgno pgno, int *pInWal, int nOut, u8 *pOut);
+
+/* If the WAL is not empty, return the size of the database. */
+SQLITE_PRIVATE Pgno sqlite3WalDbsize(Wal *pWal);
+
+/* Obtain or release the WRITER lock. */
+SQLITE_PRIVATE int sqlite3WalBeginWriteTransaction(Wal *pWal);
+SQLITE_PRIVATE int sqlite3WalEndWriteTransaction(Wal *pWal);
+
+/* Undo any frames written (but not committed) to the log */
+SQLITE_PRIVATE int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx);
+
+/* Return an integer that records the current (uncommitted) write
+** position in the WAL */
+SQLITE_PRIVATE void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData);
+
+/* Move the write position of the WAL back to iFrame.  Called in
+** response to a ROLLBACK TO command. */
+SQLITE_PRIVATE int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData);
+
+/* Write a frame or frames to the log. */
+SQLITE_PRIVATE int sqlite3WalFrames(Wal *pWal, int, PgHdr *, Pgno, int, int);
+
+/* Copy pages from the log to the database file */ 
+SQLITE_PRIVATE int sqlite3WalCheckpoint(
+  Wal *pWal,                      /* Write-ahead log connection */
+  int eMode,                      /* One of PASSIVE, FULL and RESTART */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags to sync db file with (or 0) */
+  int nBuf,                       /* Size of buffer nBuf */
+  u8 *zBuf,                       /* Temporary buffer to use */
+  int *pnLog,                     /* OUT: Number of frames in WAL */
+  int *pnCkpt                     /* OUT: Number of backfilled frames in WAL */
+);
+
+/* Return the value to pass to a sqlite3_wal_hook callback, the
+** number of frames in the WAL at the point of the last commit since
+** sqlite3WalCallback() was called.  If no commits have occurred since
+** the last call, then return 0.
+*/
+SQLITE_PRIVATE int sqlite3WalCallback(Wal *pWal);
+
+/* Tell the wal layer that an EXCLUSIVE lock has been obtained (or released)
+** by the pager layer on the database file.
+*/
+SQLITE_PRIVATE int sqlite3WalExclusiveMode(Wal *pWal, int op);
+
+/* Return true if the argument is non-NULL and the WAL module is using
+** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
+** WAL module is using shared-memory, return false. 
+*/
+SQLITE_PRIVATE int sqlite3WalHeapMemory(Wal *pWal);
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/* If the WAL file is not empty, return the number of bytes of content
+** stored in each frame (i.e. the db page-size when the WAL was created).
+*/
+SQLITE_PRIVATE int sqlite3WalFramesize(Wal *pWal);
+#endif
+
+#endif /* ifndef SQLITE_OMIT_WAL */
+#endif /* _WAL_H_ */
+
+/************** End of wal.h *************************************************/
+/************** Continuing where we left off in pager.c **********************/
+
+
+/******************* NOTES ON THE DESIGN OF THE PAGER ************************
+**
+** This comment block describes invariants that hold when using a rollback
+** journal.  These invariants do not apply for journal_mode=WAL,
+** journal_mode=MEMORY, or journal_mode=OFF.
+**
+** Within this comment block, a page is deemed to have been synced
+** automatically as soon as it is written when PRAGMA synchronous=OFF.
+** Otherwise, the page is not synced until the xSync method of the VFS
+** is called successfully on the file containing the page.
+**
+** Definition:  A page of the database file is said to be "overwriteable" if
+** one or more of the following are true about the page:
+** 
+**     (a)  The original content of the page as it was at the beginning of
+**          the transaction has been written into the rollback journal and
+**          synced.
+** 
+**     (b)  The page was a freelist leaf page at the start of the transaction.
+** 
+**     (c)  The page number is greater than the largest page that existed in
+**          the database file at the start of the transaction.
+** 
+** (1) A page of the database file is never overwritten unless one of the
+**     following are true:
+** 
+**     (a) The page and all other pages on the same sector are overwriteable.
+** 
+**     (b) The atomic page write optimization is enabled, and the entire
+**         transaction other than the update of the transaction sequence
+**         number consists of a single page change.
+** 
+** (2) The content of a page written into the rollback journal exactly matches
+**     both the content in the database when the rollback journal was written
+**     and the content in the database at the beginning of the current
+**     transaction.
+** 
+** (3) Writes to the database file are an integer multiple of the page size
+**     in length and are aligned on a page boundary.
+** 
+** (4) Reads from the database file are either aligned on a page boundary and
+**     an integer multiple of the page size in length or are taken from the
+**     first 100 bytes of the database file.
+** 
+** (5) All writes to the database file are synced prior to the rollback journal
+**     being deleted, truncated, or zeroed.
+** 
+** (6) If a master journal file is used, then all writes to the database file
+**     are synced prior to the master journal being deleted.
+** 
+** Definition: Two databases (or the same database at two points it time)
+** are said to be "logically equivalent" if they give the same answer to
+** all queries.  Note in particular the content of freelist leaf
+** pages can be changed arbitarily without effecting the logical equivalence
+** of the database.
+** 
+** (7) At any time, if any subset, including the empty set and the total set,
+**     of the unsynced changes to a rollback journal are removed and the 
+**     journal is rolled back, the resulting database file will be logical
+**     equivalent to the database file at the beginning of the transaction.
+** 
+** (8) When a transaction is rolled back, the xTruncate method of the VFS
+**     is called to restore the database file to the same size it was at
+**     the beginning of the transaction.  (In some VFSes, the xTruncate
+**     method is a no-op, but that does not change the fact the SQLite will
+**     invoke it.)
+** 
+** (9) Whenever the database file is modified, at least one bit in the range
+**     of bytes from 24 through 39 inclusive will be changed prior to releasing
+**     the EXCLUSIVE lock, thus signaling other connections on the same
+**     database to flush their caches.
+**
+** (10) The pattern of bits in bytes 24 through 39 shall not repeat in less
+**      than one billion transactions.
+**
+** (11) A database file is well-formed at the beginning and at the conclusion
+**      of every transaction.
+**
+** (12) An EXCLUSIVE lock is held on the database file when writing to
+**      the database file.
+**
+** (13) A SHARED lock is held on the database file while reading any
+**      content out of the database file.
+**
+******************************************************************************/
 
 /*
 ** Macros for troubleshooting.  Normally turned off
@@ -30798,83 +37081,301 @@ int sqlite3PagerTrace=1;  /* True to enable tracing */
 #define FILEHANDLEID(fd) ((int)fd)
 
 /*
-** The page cache as a whole is always in one of the following
-** states:
+** The Pager.eState variable stores the current 'state' of a pager. A
+** pager may be in any one of the seven states shown in the following
+** state diagram.
 **
-**   PAGER_UNLOCK        The page cache is not currently reading or 
-**                       writing the database file.  There is no
-**                       data held in memory.  This is the initial
-**                       state.
+**                            OPEN <------+------+
+**                              |         |      |
+**                              V         |      |
+**               +---------> READER-------+      |
+**               |              |                |
+**               |              V                |
+**               |<-------WRITER_LOCKED------> ERROR
+**               |              |                ^  
+**               |              V                |
+**               |<------WRITER_CACHEMOD-------->|
+**               |              |                |
+**               |              V                |
+**               |<-------WRITER_DBMOD---------->|
+**               |              |                |
+**               |              V                |
+**               +<------WRITER_FINISHED-------->+
 **
-**   PAGER_SHARED        The page cache is reading the database.
-**                       Writing is not permitted.  There can be
-**                       multiple readers accessing the same database
-**                       file at the same time.
 **
-**   PAGER_RESERVED      This process has reserved the database for writing
-**                       but has not yet made any changes.  Only one process
-**                       at a time can reserve the database.  The original
-**                       database file has not been modified so other
-**                       processes may still be reading the on-disk
-**                       database file.
+** List of state transitions and the C [function] that performs each:
+** 
+**   OPEN              -> READER              [sqlite3PagerSharedLock]
+**   READER            -> OPEN                [pager_unlock]
 **
-**   PAGER_EXCLUSIVE     The page cache is writing the database.
-**                       Access is exclusive.  No other processes or
-**                       threads can be reading or writing while one
-**                       process is writing.
+**   READER            -> WRITER_LOCKED       [sqlite3PagerBegin]
+**   WRITER_LOCKED     -> WRITER_CACHEMOD     [pager_open_journal]
+**   WRITER_CACHEMOD   -> WRITER_DBMOD        [syncJournal]
+**   WRITER_DBMOD      -> WRITER_FINISHED     [sqlite3PagerCommitPhaseOne]
+**   WRITER_***        -> READER              [pager_end_transaction]
 **
-**   PAGER_SYNCED        The pager moves to this state from PAGER_EXCLUSIVE
-**                       after all dirty pages have been written to the
-**                       database file and the file has been synced to
-**                       disk. All that remains to do is to remove or
-**                       truncate the journal file and the transaction 
-**                       will be committed.
+**   WRITER_***        -> ERROR               [pager_error]
+**   ERROR             -> OPEN                [pager_unlock]
+** 
 **
-** The page cache comes up in PAGER_UNLOCK.  The first time a
-** sqlite3PagerGet() occurs, the state transitions to PAGER_SHARED.
-** After all pages have been released using sqlite_page_unref(),
-** the state transitions back to PAGER_UNLOCK.  The first time
-** that sqlite3PagerWrite() is called, the state transitions to
-** PAGER_RESERVED.  (Note that sqlite3PagerWrite() can only be
-** called on an outstanding page which means that the pager must
-** be in PAGER_SHARED before it transitions to PAGER_RESERVED.)
-** PAGER_RESERVED means that there is an open rollback journal.
-** The transition to PAGER_EXCLUSIVE occurs before any changes
-** are made to the database file, though writes to the rollback
-** journal occurs with just PAGER_RESERVED.  After an sqlite3PagerRollback()
-** or sqlite3PagerCommitPhaseTwo(), the state can go back to PAGER_SHARED,
-** or it can stay at PAGER_EXCLUSIVE if we are in exclusive access mode.
+**  OPEN:
+**
+**    The pager starts up in this state. Nothing is guaranteed in this
+**    state - the file may or may not be locked and the database size is
+**    unknown. The database may not be read or written.
+**
+**    * No read or write transaction is active.
+**    * Any lock, or no lock at all, may be held on the database file.
+**    * The dbSize, dbOrigSize and dbFileSize variables may not be trusted.
+**
+**  READER:
+**
+**    In this state all the requirements for reading the database in 
+**    rollback (non-WAL) mode are met. Unless the pager is (or recently
+**    was) in exclusive-locking mode, a user-level read transaction is 
+**    open. The database size is known in this state.
+**
+**    A connection running with locking_mode=normal enters this state when
+**    it opens a read-transaction on the database and returns to state
+**    OPEN after the read-transaction is completed. However a connection
+**    running in locking_mode=exclusive (including temp databases) remains in
+**    this state even after the read-transaction is closed. The only way
+**    a locking_mode=exclusive connection can transition from READER to OPEN
+**    is via the ERROR state (see below).
+** 
+**    * A read transaction may be active (but a write-transaction cannot).
+**    * A SHARED or greater lock is held on the database file.
+**    * The dbSize variable may be trusted (even if a user-level read 
+**      transaction is not active). The dbOrigSize and dbFileSize variables
+**      may not be trusted at this point.
+**    * If the database is a WAL database, then the WAL connection is open.
+**    * Even if a read-transaction is not open, it is guaranteed that 
+**      there is no hot-journal in the file-system.
+**
+**  WRITER_LOCKED:
+**
+**    The pager moves to this state from READER when a write-transaction
+**    is first opened on the database. In WRITER_LOCKED state, all locks 
+**    required to start a write-transaction are held, but no actual 
+**    modifications to the cache or database have taken place.
+**
+**    In rollback mode, a RESERVED or (if the transaction was opened with 
+**    BEGIN EXCLUSIVE) EXCLUSIVE lock is obtained on the database file when
+**    moving to this state, but the journal file is not written to or opened 
+**    to in this state. If the transaction is committed or rolled back while 
+**    in WRITER_LOCKED state, all that is required is to unlock the database 
+**    file.
+**
+**    IN WAL mode, WalBeginWriteTransaction() is called to lock the log file.
+**    If the connection is running with locking_mode=exclusive, an attempt
+**    is made to obtain an EXCLUSIVE lock on the database file.
+**
+**    * A write transaction is active.
+**    * If the connection is open in rollback-mode, a RESERVED or greater 
+**      lock is held on the database file.
+**    * If the connection is open in WAL-mode, a WAL write transaction
+**      is open (i.e. sqlite3WalBeginWriteTransaction() has been successfully
+**      called).
+**    * The dbSize, dbOrigSize and dbFileSize variables are all valid.
+**    * The contents of the pager cache have not been modified.
+**    * The journal file may or may not be open.
+**    * Nothing (not even the first header) has been written to the journal.
+**
+**  WRITER_CACHEMOD:
+**
+**    A pager moves from WRITER_LOCKED state to this state when a page is
+**    first modified by the upper layer. In rollback mode the journal file
+**    is opened (if it is not already open) and a header written to the
+**    start of it. The database file on disk has not been modified.
+**
+**    * A write transaction is active.
+**    * A RESERVED or greater lock is held on the database file.
+**    * The journal file is open and the first header has been written 
+**      to it, but the header has not been synced to disk.
+**    * The contents of the page cache have been modified.
+**
+**  WRITER_DBMOD:
+**
+**    The pager transitions from WRITER_CACHEMOD into WRITER_DBMOD state
+**    when it modifies the contents of the database file. WAL connections
+**    never enter this state (since they do not modify the database file,
+**    just the log file).
+**
+**    * A write transaction is active.
+**    * An EXCLUSIVE or greater lock is held on the database file.
+**    * The journal file is open and the first header has been written 
+**      and synced to disk.
+**    * The contents of the page cache have been modified (and possibly
+**      written to disk).
+**
+**  WRITER_FINISHED:
+**
+**    It is not possible for a WAL connection to enter this state.
+**
+**    A rollback-mode pager changes to WRITER_FINISHED state from WRITER_DBMOD
+**    state after the entire transaction has been successfully written into the
+**    database file. In this state the transaction may be committed simply
+**    by finalizing the journal file. Once in WRITER_FINISHED state, it is 
+**    not possible to modify the database further. At this point, the upper 
+**    layer must either commit or rollback the transaction.
+**
+**    * A write transaction is active.
+**    * An EXCLUSIVE or greater lock is held on the database file.
+**    * All writing and syncing of journal and database data has finished.
+**      If no error occured, all that remains is to finalize the journal to
+**      commit the transaction. If an error did occur, the caller will need
+**      to rollback the transaction. 
+**
+**  ERROR:
+**
+**    The ERROR state is entered when an IO or disk-full error (including
+**    SQLITE_IOERR_NOMEM) occurs at a point in the code that makes it 
+**    difficult to be sure that the in-memory pager state (cache contents, 
+**    db size etc.) are consistent with the contents of the file-system.
+**
+**    Temporary pager files may enter the ERROR state, but in-memory pagers
+**    cannot.
+**
+**    For example, if an IO error occurs while performing a rollback, 
+**    the contents of the page-cache may be left in an inconsistent state.
+**    At this point it would be dangerous to change back to READER state
+**    (as usually happens after a rollback). Any subsequent readers might
+**    report database corruption (due to the inconsistent cache), and if
+**    they upgrade to writers, they may inadvertently corrupt the database
+**    file. To avoid this hazard, the pager switches into the ERROR state
+**    instead of READER following such an error.
+**
+**    Once it has entered the ERROR state, any attempt to use the pager
+**    to read or write data returns an error. Eventually, once all 
+**    outstanding transactions have been abandoned, the pager is able to
+**    transition back to OPEN state, discarding the contents of the 
+**    page-cache and any other in-memory state at the same time. Everything
+**    is reloaded from disk (and, if necessary, hot-journal rollback peformed)
+**    when a read-transaction is next opened on the pager (transitioning
+**    the pager into READER state). At that point the system has recovered 
+**    from the error.
+**
+**    Specifically, the pager jumps into the ERROR state if:
+**
+**      1. An error occurs while attempting a rollback. This happens in
+**         function sqlite3PagerRollback().
+**
+**      2. An error occurs while attempting to finalize a journal file
+**         following a commit in function sqlite3PagerCommitPhaseTwo().
+**
+**      3. An error occurs while attempting to write to the journal or
+**         database file in function pagerStress() in order to free up
+**         memory.
+**
+**    In other cases, the error is returned to the b-tree layer. The b-tree
+**    layer then attempts a rollback operation. If the error condition 
+**    persists, the pager enters the ERROR state via condition (1) above.
+**
+**    Condition (3) is necessary because it can be triggered by a read-only
+**    statement executed within a transaction. In this case, if the error
+**    code were simply returned to the user, the b-tree layer would not
+**    automatically attempt a rollback, as it assumes that an error in a
+**    read-only statement cannot leave the pager in an internally inconsistent 
+**    state.
+**
+**    * The Pager.errCode variable is set to something other than SQLITE_OK.
+**    * There are one or more outstanding references to pages (after the
+**      last reference is dropped the pager should move back to OPEN state).
+**    * The pager is not an in-memory pager.
+**    
+**
+** Notes:
+**
+**   * A pager is never in WRITER_DBMOD or WRITER_FINISHED state if the
+**     connection is open in WAL mode. A WAL connection is always in one
+**     of the first four states.
+**
+**   * Normally, a connection open in exclusive mode is never in PAGER_OPEN
+**     state. There are two exceptions: immediately after exclusive-mode has
+**     been turned on (and before any read or write transactions are 
+**     executed), and when the pager is leaving the "error state".
+**
+**   * See also: assert_pager_state().
 */
-#define PAGER_UNLOCK      0
-#define PAGER_SHARED      1   /* same as SHARED_LOCK */
-#define PAGER_RESERVED    2   /* same as RESERVED_LOCK */
-#define PAGER_EXCLUSIVE   4   /* same as EXCLUSIVE_LOCK */
-#define PAGER_SYNCED      5
+#define PAGER_OPEN                  0
+#define PAGER_READER                1
+#define PAGER_WRITER_LOCKED         2
+#define PAGER_WRITER_CACHEMOD       3
+#define PAGER_WRITER_DBMOD          4
+#define PAGER_WRITER_FINISHED       5
+#define PAGER_ERROR                 6
 
 /*
-** This macro rounds values up so that if the value is an address it
-** is guaranteed to be an address that is aligned to an 8-byte boundary.
+** The Pager.eLock variable is almost always set to one of the 
+** following locking-states, according to the lock currently held on
+** the database file: NO_LOCK, SHARED_LOCK, RESERVED_LOCK or EXCLUSIVE_LOCK.
+** This variable is kept up to date as locks are taken and released by
+** the pagerLockDb() and pagerUnlockDb() wrappers.
+**
+** If the VFS xLock() or xUnlock() returns an error other than SQLITE_BUSY
+** (i.e. one of the SQLITE_IOERR subtypes), it is not clear whether or not
+** the operation was successful. In these circumstances pagerLockDb() and
+** pagerUnlockDb() take a conservative approach - eLock is always updated
+** when unlocking the file, and only updated when locking the file if the
+** VFS call is successful. This way, the Pager.eLock variable may be set
+** to a less exclusive (lower) value than the lock that is actually held
+** at the system level, but it is never set to a more exclusive value.
+**
+** This is usually safe. If an xUnlock fails or appears to fail, there may 
+** be a few redundant xLock() calls or a lock may be held for longer than
+** required, but nothing really goes wrong.
+**
+** The exception is when the database file is unlocked as the pager moves
+** from ERROR to OPEN state. At this point there may be a hot-journal file 
+** in the file-system that needs to be rolled back (as part of a OPEN->SHARED
+** transition, by the same pager or any other). If the call to xUnlock()
+** fails at this point and the pager is left holding an EXCLUSIVE lock, this
+** can confuse the call to xCheckReservedLock() call made later as part
+** of hot-journal detection.
+**
+** xCheckReservedLock() is defined as returning true "if there is a RESERVED 
+** lock held by this process or any others". So xCheckReservedLock may 
+** return true because the caller itself is holding an EXCLUSIVE lock (but
+** doesn't know it because of a previous error in xUnlock). If this happens
+** a hot-journal may be mistaken for a journal being created by an active
+** transaction in another process, causing SQLite to read from the database
+** without rolling it back.
+**
+** To work around this, if a call to xUnlock() fails when unlocking the
+** database in the ERROR state, Pager.eLock is set to UNKNOWN_LOCK. It
+** is only changed back to a real locking state after a successful call
+** to xLock(EXCLUSIVE). Also, the code to do the OPEN->SHARED state transition
+** omits the check for a hot-journal if Pager.eLock is set to UNKNOWN_LOCK 
+** lock. Instead, it assumes a hot-journal exists and obtains an EXCLUSIVE
+** lock on the database file before attempting to roll it back. See function
+** PagerSharedLock() for more detail.
+**
+** Pager.eLock may only be set to UNKNOWN_LOCK when the pager is in 
+** PAGER_OPEN state.
 */
-#define FORCE_ALIGNMENT(X)   (((X)+7)&~7)
+#define UNKNOWN_LOCK                (EXCLUSIVE_LOCK+1)
 
 /*
 ** A macro used for invoking the codec if there is one
 */
 #ifdef SQLITE_HAS_CODEC
-# define CODEC1(P,D,N,X) if( P->xCodec!=0 ){ P->xCodec(P->pCodecArg,D,N,X); }
-# define CODEC2(P,D,N,X) ((char*)(P->xCodec!=0?P->xCodec(P->pCodecArg,D,N,X):D))
+# define CODEC1(P,D,N,X,E) \
+    if( P->xCodec && P->xCodec(P->pCodec,D,N,X)==0 ){ E; }
+# define CODEC2(P,D,N,X,E,O) \
+    if( P->xCodec==0 ){ O=(char*)D; }else \
+    if( (O=(char*)(P->xCodec(P->pCodec,D,N,X)))==0 ){ E; }
 #else
-# define CODEC1(P,D,N,X) /* NO-OP */
-# define CODEC2(P,D,N,X) ((char*)D)
+# define CODEC1(P,D,N,X,E)   /* NO-OP */
+# define CODEC2(P,D,N,X,E,O) O=(char*)D
 #endif
 
 /*
-** The maximum allowed sector size. 16MB. If the xSectorsize() method 
+** The maximum allowed sector size. 64KiB. If the xSectorsize() method 
 ** returns a value larger than this, then MAX_SECTOR_SIZE is used instead.
 ** This could conceivably cause corruption following a power failure on
 ** such a system. This is currently an undocumented limit.
 */
-#define MAX_SECTOR_SIZE 0x0100000
+#define MAX_SECTOR_SIZE 0x10000
 
 /*
 ** An instance of the following structure is allocated for each active
@@ -30896,95 +37397,256 @@ struct PagerSavepoint {
   Bitvec *pInSavepoint;        /* Set of pages in this savepoint */
   Pgno nOrig;                  /* Original number of pages in file */
   Pgno iSubRec;                /* Index of first record in sub-journal */
+#ifndef SQLITE_OMIT_WAL
+  u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
+#endif
 };
 
 /*
-** A open page cache is an instance of the following structure.
+** A open page cache is an instance of struct Pager. A description of
+** some of the more important member variables follows:
 **
-** Pager.errCode may be set to SQLITE_IOERR, SQLITE_CORRUPT, or
-** or SQLITE_FULL. Once one of the first three errors occurs, it persists
-** and is returned as the result of every major pager API call.  The
-** SQLITE_FULL return code is slightly different. It persists only until the
-** next successful rollback is performed on the pager cache. Also,
-** SQLITE_FULL does not affect the sqlite3PagerGet() and sqlite3PagerLookup()
-** APIs, they may still be used successfully.
+** eState
 **
-** Managing the size of the database file in pages is a little complicated.
-** The variable Pager.dbSize contains the number of pages that the database
-** image currently contains. As the database image grows or shrinks this
-** variable is updated. The variable Pager.dbFileSize contains the number
-** of pages in the database file. This may be different from Pager.dbSize
-** if some pages have been appended to the database image but not yet written
-** out from the cache to the actual file on disk. Or if the image has been
-** truncated by an incremental-vacuum operation. The Pager.dbOrigSize variable
-** contains the number of pages in the database image when the current
-** transaction was opened. The contents of all three of these variables is
-** only guaranteed to be correct if the boolean Pager.dbSizeValid is true.
+**   The current 'state' of the pager object. See the comment and state
+**   diagram above for a description of the pager state.
+**
+** eLock
+**
+**   For a real on-disk database, the current lock held on the database file -
+**   NO_LOCK, SHARED_LOCK, RESERVED_LOCK or EXCLUSIVE_LOCK.
+**
+**   For a temporary or in-memory database (neither of which require any
+**   locks), this variable is always set to EXCLUSIVE_LOCK. Since such
+**   databases always have Pager.exclusiveMode==1, this tricks the pager
+**   logic into thinking that it already has all the locks it will ever
+**   need (and no reason to release them).
+**
+**   In some (obscure) circumstances, this variable may also be set to
+**   UNKNOWN_LOCK. See the comment above the #define of UNKNOWN_LOCK for
+**   details.
+**
+** changeCountDone
+**
+**   This boolean variable is used to make sure that the change-counter 
+**   (the 4-byte header field at byte offset 24 of the database file) is 
+**   not updated more often than necessary. 
+**
+**   It is set to true when the change-counter field is updated, which 
+**   can only happen if an exclusive lock is held on the database file.
+**   It is cleared (set to false) whenever an exclusive lock is 
+**   relinquished on the database file. Each time a transaction is committed,
+**   The changeCountDone flag is inspected. If it is true, the work of
+**   updating the change-counter is omitted for the current transaction.
+**
+**   This mechanism means that when running in exclusive mode, a connection 
+**   need only update the change-counter once, for the first transaction
+**   committed.
+**
+** setMaster
+**
+**   When PagerCommitPhaseOne() is called to commit a transaction, it may
+**   (or may not) specify a master-journal name to be written into the 
+**   journal file before it is synced to disk.
+**
+**   Whether or not a journal file contains a master-journal pointer affects 
+**   the way in which the journal file is finalized after the transaction is 
+**   committed or rolled back when running in "journal_mode=PERSIST" mode.
+**   If a journal file does not contain a master-journal pointer, it is
+**   finalized by overwriting the first journal header with zeroes. If
+**   it does contain a master-journal pointer the journal file is finalized 
+**   by truncating it to zero bytes, just as if the connection were 
+**   running in "journal_mode=truncate" mode.
+**
+**   Journal files that contain master journal pointers cannot be finalized
+**   simply by overwriting the first journal-header with zeroes, as the
+**   master journal pointer could interfere with hot-journal rollback of any
+**   subsequently interrupted transaction that reuses the journal file.
+**
+**   The flag is cleared as soon as the journal file is finalized (either
+**   by PagerCommitPhaseTwo or PagerRollback). If an IO error prevents the
+**   journal file from being successfully finalized, the setMaster flag
+**   is cleared anyway (and the pager will move to ERROR state).
+**
+** doNotSpill, doNotSyncSpill
+**
+**   These two boolean variables control the behaviour of cache-spills
+**   (calls made by the pcache module to the pagerStress() routine to
+**   write cached data to the file-system in order to free up memory).
+**
+**   When doNotSpill is non-zero, writing to the database from pagerStress()
+**   is disabled altogether. This is done in a very obscure case that
+**   comes up during savepoint rollback that requires the pcache module
+**   to allocate a new page to prevent the journal file from being written
+**   while it is being traversed by code in pager_playback().
+** 
+**   If doNotSyncSpill is non-zero, writing to the database from pagerStress()
+**   is permitted, but syncing the journal file is not. This flag is set
+**   by sqlite3PagerWrite() when the file-system sector-size is larger than
+**   the database page-size in order to prevent a journal sync from happening 
+**   in between the journalling of two pages on the same sector. 
+**
+** subjInMemory
+**
+**   This is a boolean variable. If true, then any required sub-journal
+**   is opened as an in-memory journal file. If false, then in-memory
+**   sub-journals are only used for in-memory pager files.
+**
+**   This variable is updated by the upper layer each time a new 
+**   write-transaction is opened.
+**
+** dbSize, dbOrigSize, dbFileSize
+**
+**   Variable dbSize is set to the number of pages in the database file.
+**   It is valid in PAGER_READER and higher states (all states except for
+**   OPEN and ERROR). 
+**
+**   dbSize is set based on the size of the database file, which may be 
+**   larger than the size of the database (the value stored at offset
+**   28 of the database header by the btree). If the size of the file
+**   is not an integer multiple of the page-size, the value stored in
+**   dbSize is rounded down (i.e. a 5KB file with 2K page-size has dbSize==2).
+**   Except, any file that is greater than 0 bytes in size is considered
+**   to have at least one page. (i.e. a 1KB file with 2K page-size leads
+**   to dbSize==1).
+**
+**   During a write-transaction, if pages with page-numbers greater than
+**   dbSize are modified in the cache, dbSize is updated accordingly.
+**   Similarly, if the database is truncated using PagerTruncateImage(), 
+**   dbSize is updated.
+**
+**   Variables dbOrigSize and dbFileSize are valid in states 
+**   PAGER_WRITER_LOCKED and higher. dbOrigSize is a copy of the dbSize
+**   variable at the start of the transaction. It is used during rollback,
+**   and to determine whether or not pages need to be journalled before
+**   being modified.
+**
+**   Throughout a write-transaction, dbFileSize contains the size of
+**   the file on disk in pages. It is set to a copy of dbSize when the
+**   write-transaction is first opened, and updated when VFS calls are made
+**   to write or truncate the database file on disk. 
+**
+**   The only reason the dbFileSize variable is required is to suppress 
+**   unnecessary calls to xTruncate() after committing a transaction. If, 
+**   when a transaction is committed, the dbFileSize variable indicates 
+**   that the database file is larger than the database image (Pager.dbSize), 
+**   pager_truncate() is called. The pager_truncate() call uses xFilesize()
+**   to measure the database file on disk, and then truncates it if required.
+**   dbFileSize is not used when rolling back a transaction. In this case
+**   pager_truncate() is called unconditionally (which means there may be
+**   a call to xFilesize() that is not strictly required). In either case,
+**   pager_truncate() may cause the file to become smaller or larger.
+**
+** dbHintSize
+**
+**   The dbHintSize variable is used to limit the number of calls made to
+**   the VFS xFileControl(FCNTL_SIZE_HINT) method. 
+**
+**   dbHintSize is set to a copy of the dbSize variable when a
+**   write-transaction is opened (at the same time as dbFileSize and
+**   dbOrigSize). If the xFileControl(FCNTL_SIZE_HINT) method is called,
+**   dbHintSize is increased to the number of pages that correspond to the
+**   size-hint passed to the method call. See pager_write_pagelist() for 
+**   details.
+**
+** errCode
+**
+**   The Pager.errCode variable is only ever used in PAGER_ERROR state. It
+**   is set to zero in all other states. In PAGER_ERROR state, Pager.errCode 
+**   is always set to SQLITE_FULL, SQLITE_IOERR or one of the SQLITE_IOERR_XXX 
+**   sub-codes.
 */
 struct Pager {
   sqlite3_vfs *pVfs;          /* OS functions to use for IO */
-  u8 journalOpen;             /* True if journal file descriptors is valid */
-  u8 journalStarted;          /* True if header of journal is synced */
+  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
+  u8 journalMode;             /* One of the PAGER_JOURNALMODE_* values */
   u8 useJournal;              /* Use a rollback journal on this file */
-  u8 noReadlock;              /* Do not bother to obtain readlocks */
   u8 noSync;                  /* Do not sync the journal if true */
   u8 fullSync;                /* Do extra syncs of the journal for robustness */
-  u8 sync_flags;              /* One of SYNC_NORMAL or SYNC_FULL */
-  u8 state;                   /* PAGER_UNLOCK, _SHARED, _RESERVED, etc. */
+  u8 ckptSyncFlags;           /* SYNC_NORMAL or SYNC_FULL for checkpoint */
+  u8 walSyncFlags;            /* SYNC_NORMAL or SYNC_FULL for wal writes */
+  u8 syncFlags;               /* SYNC_NORMAL or SYNC_FULL otherwise */
   u8 tempFile;                /* zFilename is a temporary file */
   u8 readOnly;                /* True for a read-only database */
-  u8 needSync;                /* True if an fsync() is needed on the journal */
-  u8 dirtyCache;              /* True if cached pages have changed */
   u8 memDb;                   /* True to inhibit all file I/O */
-  u8 setMaster;               /* True if a m-j name has been written to jrnl */
-  u8 doNotSync;               /* Boolean. While true, do not spill the cache */
-  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
-  u8 journalMode;             /* On of the PAGER_JOURNALMODE_* values */
-  u8 dbModified;              /* True if there are any changes to the Db */
+
+  /**************************************************************************
+  ** The following block contains those class members that change during
+  ** routine opertion.  Class members not in this block are either fixed
+  ** when the pager is first created or else only change when there is a
+  ** significant mode change (such as changing the page_size, locking_mode,
+  ** or the journal_mode).  From another view, these class members describe
+  ** the "state" of the pager, while other class members describe the
+  ** "configuration" of the pager.
+  */
+  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
+  u8 eLock;                   /* Current lock held on database file */
   u8 changeCountDone;         /* Set after incrementing the change-counter */
-  u8 dbSizeValid;             /* Set when dbSize is correct */
+  u8 setMaster;               /* True if a m-j name has been written to jrnl */
+  u8 doNotSpill;              /* Do not spill the cache when non-zero */
+  u8 doNotSyncSpill;          /* Do not do a spill that requires jrnl sync */
+  u8 subjInMemory;            /* True to use in-memory sub-journals */
   Pgno dbSize;                /* Number of pages in the database */
   Pgno dbOrigSize;            /* dbSize before the current transaction */
   Pgno dbFileSize;            /* Number of pages in the database file */
-  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
+  Pgno dbHintSize;            /* Value passed to FCNTL_SIZE_HINT call */
   int errCode;                /* One of several kinds of errors */
-  int nRec;                   /* Number of pages written to the journal */
+  int nRec;                   /* Pages journalled since last j-header written */
   u32 cksumInit;              /* Quasi-random value added to every checksum */
-  int stmtNRec;               /* Number of records in stmt subjournal */
-  int nExtra;                 /* Add this many bytes to each in-memory page */
-  int pageSize;               /* Number of bytes in a page */
-  int nPage;                  /* Total number of in-memory pages */
-  int mxPage;                 /* Maximum number of pages to hold in cache */
-  Pgno mxPgno;                /* Maximum allowed size of the database */
+  u32 nSubRec;                /* Number of records written to sub-journal */
   Bitvec *pInJournal;         /* One bit for each page in the database file */
-  Bitvec *pAlwaysRollback;    /* One bit for each page marked always-rollback */
+  sqlite3_file *fd;           /* File descriptor for database */
+  sqlite3_file *jfd;          /* File descriptor for main journal */
+  sqlite3_file *sjfd;         /* File descriptor for sub-journal */
+  i64 journalOff;             /* Current write offset in the journal file */
+  i64 journalHdr;             /* Byte offset to previous journal header */
+  sqlite3_backup *pBackup;    /* Pointer to list of ongoing backup processes */
+  PagerSavepoint *aSavepoint; /* Array of active savepoints */
+  int nSavepoint;             /* Number of elements in aSavepoint[] */
+  char dbFileVers[16];        /* Changes whenever database file changes */
+  /*
+  ** End of the routinely-changing class members
+  ***************************************************************************/
+
+  u16 nExtra;                 /* Add this many bytes to each in-memory page */
+  i16 nReserve;               /* Number of unused bytes at end of each page */
+  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
+  u32 sectorSize;             /* Assumed sector size during rollback */
+  int pageSize;               /* Number of bytes in a page */
+  Pgno mxPgno;                /* Maximum allowed size of the database */
+  i64 journalSizeLimit;       /* Size limit for persistent journal files */
   char *zFilename;            /* Name of the database file */
   char *zJournal;             /* Name of the journal file */
-  char *zDirectory;           /* Directory hold database and journal files */
-  sqlite3_file *fd, *jfd;     /* File descriptors for database and journal */
-  sqlite3_file *sjfd;         /* File descriptor for the sub-journal*/
   int (*xBusyHandler)(void*); /* Function to call when busy */
   void *pBusyHandlerArg;      /* Context argument for xBusyHandler */
-  i64 journalOff;             /* Current byte offset in the journal file */
-  i64 journalHdr;             /* Byte offset to previous journal header */
-  u32 sectorSize;             /* Assumed sector size during rollback */
+  int aStat[3];               /* Total cache hits, misses and writes */
 #ifdef SQLITE_TEST
-  int nHit, nMiss;            /* Cache hits and missing */
-  int nRead, nWrite;          /* Database pages read/written */
+  int nRead;                  /* Database pages read */
 #endif
   void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
 #ifdef SQLITE_HAS_CODEC
   void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
-  void *pCodecArg;            /* First argument to xCodec() */
+  void (*xCodecSizeChng)(void*,int,int); /* Notify of page size changes */
+  void (*xCodecFree)(void*);             /* Destructor for the codec */
+  void *pCodec;               /* First argument to xCodec... methods */
 #endif
   char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
-  char dbFileVers[16];        /* Changes whenever database file changes */
-  i64 journalSizeLimit;       /* Size limit for persistent journal files */
   PCache *pPCache;            /* Pointer to page cache object */
-  PagerSavepoint *aSavepoint; /* Array of active savepoints */
-  int nSavepoint;             /* Number of elements in aSavepoint[] */
+#ifndef SQLITE_OMIT_WAL
+  Wal *pWal;                  /* Write-ahead log used by "journal_mode=wal" */
+  char *zWal;                 /* File name for write-ahead log */
+#endif
 };
 
+/*
+** Indexes for use with Pager.aStat[]. The Pager.aStat[] array contains
+** the values accessed by passing SQLITE_DBSTATUS_CACHE_HIT, CACHE_MISS 
+** or CACHE_WRITE to sqlite3_db_status().
+*/
+#define PAGER_STAT_HIT   0
+#define PAGER_STAT_MISS  1
+#define PAGER_STAT_WRITE 2
+
 /*
 ** The following global variables hold counters used for
 ** testing purposes only.  These variables do not exist in
@@ -31029,15 +37691,14 @@ static const unsigned char aJournalMagic[] = {
 };
 
 /*
-** The size of the header and of each page in the journal is determined
-** by the following macros.
+** The size of the of each page record in the journal is given by
+** the following macro.
 */
 #define JOURNAL_PG_SZ(pPager)  ((pPager->pageSize) + 8)
 
 /*
-** The journal header size for this pager. In the future, this could be
-** set to some value read from the disk controller. The important
-** characteristic is that it is the same size as a disk sector.
+** The journal header size for this pager. This is usually the same 
+** size as a single disk sector. See also setSectorSize().
 */
 #define JOURNAL_HDR_SZ(pPager) (pPager->sectorSize)
 
@@ -31053,21 +37714,230 @@ static const unsigned char aJournalMagic[] = {
 # define MEMDB pPager->memDb
 #endif
 
-/*
-** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is
-** reserved for working around a windows/posix incompatibility). It is
-** used in the journal to signify that the remainder of the journal file 
-** is devoted to storing a master journal name - there are no more pages to
-** roll back. See comments for function writeMasterJournal() for details.
-*/
-/* #define PAGER_MJ_PGNO(x) (PENDING_BYTE/((x)->pageSize)) */
-#define PAGER_MJ_PGNO(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1))
-
 /*
 ** The maximum legal page number is (2^31 - 1).
 */
 #define PAGER_MAX_PGNO 2147483647
 
+/*
+** The argument to this macro is a file descriptor (type sqlite3_file*).
+** Return 0 if it is not open, or non-zero (but not 1) if it is.
+**
+** This is so that expressions can be written as:
+**
+**   if( isOpen(pPager->jfd) ){ ...
+**
+** instead of
+**
+**   if( pPager->jfd->pMethods ){ ...
+*/
+#define isOpen(pFd) ((pFd)->pMethods)
+
+/*
+** Return true if this pager uses a write-ahead log instead of the usual
+** rollback journal. Otherwise false.
+*/
+#ifndef SQLITE_OMIT_WAL
+static int pagerUseWal(Pager *pPager){
+  return (pPager->pWal!=0);
+}
+#else
+# define pagerUseWal(x) 0
+# define pagerRollbackWal(x) 0
+# define pagerWalFrames(v,w,x,y) 0
+# define pagerOpenWalIfPresent(z) SQLITE_OK
+# define pagerBeginReadTransaction(z) SQLITE_OK
+#endif
+
+#ifndef NDEBUG 
+/*
+** Usage:
+**
+**   assert( assert_pager_state(pPager) );
+**
+** This function runs many asserts to try to find inconsistencies in
+** the internal state of the Pager object.
+*/
+static int assert_pager_state(Pager *p){
+  Pager *pPager = p;
+
+  /* State must be valid. */
+  assert( p->eState==PAGER_OPEN
+       || p->eState==PAGER_READER
+       || p->eState==PAGER_WRITER_LOCKED
+       || p->eState==PAGER_WRITER_CACHEMOD
+       || p->eState==PAGER_WRITER_DBMOD
+       || p->eState==PAGER_WRITER_FINISHED
+       || p->eState==PAGER_ERROR
+  );
+
+  /* Regardless of the current state, a temp-file connection always behaves
+  ** as if it has an exclusive lock on the database file. It never updates
+  ** the change-counter field, so the changeCountDone flag is always set.
+  */
+  assert( p->tempFile==0 || p->eLock==EXCLUSIVE_LOCK );
+  assert( p->tempFile==0 || pPager->changeCountDone );
+
+  /* If the useJournal flag is clear, the journal-mode must be "OFF". 
+  ** And if the journal-mode is "OFF", the journal file must not be open.
+  */
+  assert( p->journalMode==PAGER_JOURNALMODE_OFF || p->useJournal );
+  assert( p->journalMode!=PAGER_JOURNALMODE_OFF || !isOpen(p->jfd) );
+
+  /* Check that MEMDB implies noSync. And an in-memory journal. Since 
+  ** this means an in-memory pager performs no IO at all, it cannot encounter 
+  ** either SQLITE_IOERR or SQLITE_FULL during rollback or while finalizing 
+  ** a journal file. (although the in-memory journal implementation may 
+  ** return SQLITE_IOERR_NOMEM while the journal file is being written). It 
+  ** is therefore not possible for an in-memory pager to enter the ERROR 
+  ** state.
+  */
+  if( MEMDB ){
+    assert( p->noSync );
+    assert( p->journalMode==PAGER_JOURNALMODE_OFF 
+         || p->journalMode==PAGER_JOURNALMODE_MEMORY 
+    );
+    assert( p->eState!=PAGER_ERROR && p->eState!=PAGER_OPEN );
+    assert( pagerUseWal(p)==0 );
+  }
+
+  /* If changeCountDone is set, a RESERVED lock or greater must be held
+  ** on the file.
+  */
+  assert( pPager->changeCountDone==0 || pPager->eLock>=RESERVED_LOCK );
+  assert( p->eLock!=PENDING_LOCK );
+
+  switch( p->eState ){
+    case PAGER_OPEN:
+      assert( !MEMDB );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( sqlite3PcacheRefCount(pPager->pPCache)==0 || pPager->tempFile );
+      break;
+
+    case PAGER_READER:
+      assert( pPager->errCode==SQLITE_OK );
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( p->eLock>=SHARED_LOCK );
+      break;
+
+    case PAGER_WRITER_LOCKED:
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      if( !pagerUseWal(pPager) ){
+        assert( p->eLock>=RESERVED_LOCK );
+      }
+      assert( pPager->dbSize==pPager->dbOrigSize );
+      assert( pPager->dbOrigSize==pPager->dbFileSize );
+      assert( pPager->dbOrigSize==pPager->dbHintSize );
+      assert( pPager->setMaster==0 );
+      break;
+
+    case PAGER_WRITER_CACHEMOD:
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      if( !pagerUseWal(pPager) ){
+        /* It is possible that if journal_mode=wal here that neither the
+        ** journal file nor the WAL file are open. This happens during
+        ** a rollback transaction that switches from journal_mode=off
+        ** to journal_mode=wal.
+        */
+        assert( p->eLock>=RESERVED_LOCK );
+        assert( isOpen(p->jfd) 
+             || p->journalMode==PAGER_JOURNALMODE_OFF 
+             || p->journalMode==PAGER_JOURNALMODE_WAL 
+        );
+      }
+      assert( pPager->dbOrigSize==pPager->dbFileSize );
+      assert( pPager->dbOrigSize==pPager->dbHintSize );
+      break;
+
+    case PAGER_WRITER_DBMOD:
+      assert( p->eLock==EXCLUSIVE_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( !pagerUseWal(pPager) );
+      assert( p->eLock>=EXCLUSIVE_LOCK );
+      assert( isOpen(p->jfd) 
+           || p->journalMode==PAGER_JOURNALMODE_OFF 
+           || p->journalMode==PAGER_JOURNALMODE_WAL 
+      );
+      assert( pPager->dbOrigSize<=pPager->dbHintSize );
+      break;
+
+    case PAGER_WRITER_FINISHED:
+      assert( p->eLock==EXCLUSIVE_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( !pagerUseWal(pPager) );
+      assert( isOpen(p->jfd) 
+           || p->journalMode==PAGER_JOURNALMODE_OFF 
+           || p->journalMode==PAGER_JOURNALMODE_WAL 
+      );
+      break;
+
+    case PAGER_ERROR:
+      /* There must be at least one outstanding reference to the pager if
+      ** in ERROR state. Otherwise the pager should have already dropped
+      ** back to OPEN state.
+      */
+      assert( pPager->errCode!=SQLITE_OK );
+      assert( sqlite3PcacheRefCount(pPager->pPCache)>0 );
+      break;
+  }
+
+  return 1;
+}
+#endif /* ifndef NDEBUG */
+
+#ifdef SQLITE_DEBUG 
+/*
+** Return a pointer to a human readable string in a static buffer
+** containing the state of the Pager object passed as an argument. This
+** is intended to be used within debuggers. For example, as an alternative
+** to "print *pPager" in gdb:
+**
+** (gdb) printf "%s", print_pager_state(pPager)
+*/
+static char *print_pager_state(Pager *p){
+  static char zRet[1024];
+
+  sqlite3_snprintf(1024, zRet,
+      "Filename:      %s\n"
+      "State:         %s errCode=%d\n"
+      "Lock:          %s\n"
+      "Locking mode:  locking_mode=%s\n"
+      "Journal mode:  journal_mode=%s\n"
+      "Backing store: tempFile=%d memDb=%d useJournal=%d\n"
+      "Journal:       journalOff=%lld journalHdr=%lld\n"
+      "Size:          dbsize=%d dbOrigSize=%d dbFileSize=%d\n"
+      , p->zFilename
+      , p->eState==PAGER_OPEN            ? "OPEN" :
+        p->eState==PAGER_READER          ? "READER" :
+        p->eState==PAGER_WRITER_LOCKED   ? "WRITER_LOCKED" :
+        p->eState==PAGER_WRITER_CACHEMOD ? "WRITER_CACHEMOD" :
+        p->eState==PAGER_WRITER_DBMOD    ? "WRITER_DBMOD" :
+        p->eState==PAGER_WRITER_FINISHED ? "WRITER_FINISHED" :
+        p->eState==PAGER_ERROR           ? "ERROR" : "?error?"
+      , (int)p->errCode
+      , p->eLock==NO_LOCK         ? "NO_LOCK" :
+        p->eLock==RESERVED_LOCK   ? "RESERVED" :
+        p->eLock==EXCLUSIVE_LOCK  ? "EXCLUSIVE" :
+        p->eLock==SHARED_LOCK     ? "SHARED" :
+        p->eLock==UNKNOWN_LOCK    ? "UNKNOWN" : "?error?"
+      , p->exclusiveMode ? "exclusive" : "normal"
+      , p->journalMode==PAGER_JOURNALMODE_MEMORY   ? "memory" :
+        p->journalMode==PAGER_JOURNALMODE_OFF      ? "off" :
+        p->journalMode==PAGER_JOURNALMODE_DELETE   ? "delete" :
+        p->journalMode==PAGER_JOURNALMODE_PERSIST  ? "persist" :
+        p->journalMode==PAGER_JOURNALMODE_TRUNCATE ? "truncate" :
+        p->journalMode==PAGER_JOURNALMODE_WAL      ? "wal" : "?error?"
+      , (int)p->tempFile, (int)p->memDb, (int)p->useJournal
+      , p->journalOff, p->journalHdr
+      , (int)p->dbSize, (int)p->dbOrigSize, (int)p->dbFileSize
+  );
+
+  return zRet;
+}
+#endif
+
 /*
 ** Return true if it is necessary to write page *pPg into the sub-journal.
 ** A page needs to be written into the sub-journal if there exists one
@@ -31118,6 +37988,7 @@ static int read32bits(sqlite3_file *fd, i64 offset, u32 *pRes){
 */
 #define put32bits(A,B)  sqlite3Put4byte((u8*)A,B)
 
+
 /*
 ** Write a 32-bit integer into the given file descriptor.  Return SQLITE_OK
 ** on success or an error code is something goes wrong.
@@ -31129,13 +38000,53 @@ static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
 }
 
 /*
-** If file pFd is open, call sqlite3OsUnlock() on it.
+** Unlock the database file to level eLock, which must be either NO_LOCK
+** or SHARED_LOCK. Regardless of whether or not the call to xUnlock()
+** succeeds, set the Pager.eLock variable to match the (attempted) new lock.
+**
+** Except, if Pager.eLock is set to UNKNOWN_LOCK when this function is
+** called, do not modify it. See the comment above the #define of 
+** UNKNOWN_LOCK for an explanation of this.
 */
-static int osUnlock(sqlite3_file *pFd, int eLock){
-  if( !pFd->pMethods ){
-    return SQLITE_OK;
+static int pagerUnlockDb(Pager *pPager, int eLock){
+  int rc = SQLITE_OK;
+
+  assert( !pPager->exclusiveMode || pPager->eLock==eLock );
+  assert( eLock==NO_LOCK || eLock==SHARED_LOCK );
+  assert( eLock!=NO_LOCK || pagerUseWal(pPager)==0 );
+  if( isOpen(pPager->fd) ){
+    assert( pPager->eLock>=eLock );
+    rc = sqlite3OsUnlock(pPager->fd, eLock);
+    if( pPager->eLock!=UNKNOWN_LOCK ){
+      pPager->eLock = (u8)eLock;
+    }
+    IOTRACE(("UNLOCK %p %d\n", pPager, eLock))
   }
-  return sqlite3OsUnlock(pFd, eLock);
+  return rc;
+}
+
+/*
+** Lock the database file to level eLock, which must be either SHARED_LOCK,
+** RESERVED_LOCK or EXCLUSIVE_LOCK. If the caller is successful, set the
+** Pager.eLock variable to the new locking state. 
+**
+** Except, if Pager.eLock is set to UNKNOWN_LOCK when this function is 
+** called, do not modify it unless the new locking state is EXCLUSIVE_LOCK. 
+** See the comment above the #define of UNKNOWN_LOCK for an explanation 
+** of this.
+*/
+static int pagerLockDb(Pager *pPager, int eLock){
+  int rc = SQLITE_OK;
+
+  assert( eLock==SHARED_LOCK || eLock==RESERVED_LOCK || eLock==EXCLUSIVE_LOCK );
+  if( pPager->eLock<eLock || pPager->eLock==UNKNOWN_LOCK ){
+    rc = sqlite3OsLock(pPager->fd, eLock);
+    if( rc==SQLITE_OK && (pPager->eLock!=UNKNOWN_LOCK||eLock==EXCLUSIVE_LOCK) ){
+      pPager->eLock = (u8)eLock;
+      IOTRACE(("LOCK %p %d\n", pPager, eLock))
+    }
+  }
+  return rc;
 }
 
 /*
@@ -31147,77 +38058,37 @@ static int osUnlock(sqlite3_file *pFd, int eLock){
 **  (b) the value returned by OsSectorSize() is less than or equal
 **      to the page size.
 **
+** The optimization is also always enabled for temporary files. It is
+** an error to call this function if pPager is opened on an in-memory
+** database.
+**
 ** If the optimization cannot be used, 0 is returned. If it can be used,
 ** then the value returned is the size of the journal file when it
 ** contains rollback data for exactly one page.
 */
 #ifdef SQLITE_ENABLE_ATOMIC_WRITE
 static int jrnlBufferSize(Pager *pPager){
-  int dc;           /* Device characteristics */
-  int nSector;      /* Sector size */
-  int szPage;        /* Page size */
-  sqlite3_file *fd = pPager->fd;
+  assert( !MEMDB );
+  if( !pPager->tempFile ){
+    int dc;                           /* Device characteristics */
+    int nSector;                      /* Sector size */
+    int szPage;                       /* Page size */
 
-  if( fd->pMethods ){
-    dc = sqlite3OsDeviceCharacteristics(fd);
+    assert( isOpen(pPager->fd) );
+    dc = sqlite3OsDeviceCharacteristics(pPager->fd);
     nSector = pPager->sectorSize;
     szPage = pPager->pageSize;
-  }
 
-  assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
-  assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
-
-  if( !fd->pMethods || 
-       (dc & (SQLITE_IOCAP_ATOMIC|(szPage>>8)) && nSector<=szPage) ){
-    return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
-  }
-  return 0;
-}
-#endif
-
-/*
-** This function should be called when an error occurs within the pager
-** code. The first argument is a pointer to the pager structure, the
-** second the error-code about to be returned by a pager API function. 
-** The value returned is a copy of the second argument to this function. 
-**
-** If the second argument is SQLITE_IOERR, SQLITE_CORRUPT, or SQLITE_FULL
-** the error becomes persistent. Until the persisten error is cleared,
-** subsequent API calls on this Pager will immediately return the same 
-** error code.
-**
-** A persistent error indicates that the contents of the pager-cache 
-** cannot be trusted. This state can be cleared by completely discarding 
-** the contents of the pager-cache. If a transaction was active when
-** the persistent error occured, then the rollback journal may need
-** to be replayed.
-*/
-static void pager_unlock(Pager *pPager);
-static int pager_error(Pager *pPager, int rc){
-  int rc2 = rc & 0xff;
-  assert(
-       pPager->errCode==SQLITE_FULL ||
-       pPager->errCode==SQLITE_OK ||
-       (pPager->errCode & 0xff)==SQLITE_IOERR
-  );
-  if(
-    rc2==SQLITE_FULL ||
-    rc2==SQLITE_IOERR ||
-    rc2==SQLITE_CORRUPT
-  ){
-    pPager->errCode = rc;
-    if( pPager->state==PAGER_UNLOCK 
-     && sqlite3PcacheRefCount(pPager->pPCache)==0 
-    ){
-      /* If the pager is already unlocked, call pager_unlock() now to
-      ** clear the error state and ensure that the pager-cache is 
-      ** completely empty.
-      */
-      pager_unlock(pPager);
+    assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+    assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+    if( 0==(dc&(SQLITE_IOCAP_ATOMIC|(szPage>>8)) || nSector>szPage) ){
+      return 0;
     }
   }
-  return rc;
+
+  return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
 }
+#endif
 
 /*
 ** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
@@ -31251,20 +38122,23 @@ static void pager_set_pagehash(PgHdr *pPage){
 #define CHECK_PAGE(x) checkPage(x)
 static void checkPage(PgHdr *pPg){
   Pager *pPager = pPg->pPager;
-  assert( !pPg->pageHash || pPager->errCode
-      || (pPg->flags&PGHDR_DIRTY) || pPg->pageHash==pager_pagehash(pPg) );
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( (pPg->flags&PGHDR_DIRTY) || pPg->pageHash==pager_pagehash(pPg) );
 }
 
 #else
 #define pager_datahash(X,Y)  0
 #define pager_pagehash(X)  0
+#define pager_set_pagehash(X)
 #define CHECK_PAGE(x)
 #endif  /* SQLITE_CHECK_PAGES */
 
 /*
 ** When this is called the journal file for pager pPager must be open.
-** The master journal file name is read from the end of the file and 
-** written into memory supplied by the caller. 
+** This function attempts to read a master journal file name from the 
+** end of the file and, if successful, copies it into memory supplied 
+** by the caller. See comments above writeMasterJournal() for the format
+** used to store a master journal file name at the end of a journal file.
 **
 ** zMaster must point to a buffer of at least nMaster bytes allocated by
 ** the caller. This should be sqlite3_vfs.mxPathname+1 (to ensure there is
@@ -31273,70 +38147,68 @@ static void checkPage(PgHdr *pPg){
 ** nul-terminator), then this is handled as if no master journal name
 ** were present in the journal.
 **
-** If no master journal file name is present zMaster[0] is set to 0 and
-** SQLITE_OK returned.
+** If a master journal file name is present at the end of the journal
+** file, then it is copied into the buffer pointed to by zMaster. A
+** nul-terminator byte is appended to the buffer following the master
+** journal file name.
+**
+** If it is determined that no master journal file name is present 
+** zMaster[0] is set to 0 and SQLITE_OK returned.
+**
+** If an error occurs while reading from the journal file, an SQLite
+** error code is returned.
 */
 static int readMasterJournal(sqlite3_file *pJrnl, char *zMaster, u32 nMaster){
-  int rc;
-  u32 len;
-  i64 szJ;
-  u32 cksum;
-  u32 u;                   /* Unsigned loop counter */
-  unsigned char aMagic[8]; /* A buffer to hold the magic header */
-
+  int rc;                    /* Return code */
+  u32 len;                   /* Length in bytes of master journal name */
+  i64 szJ;                   /* Total size in bytes of journal file pJrnl */
+  u32 cksum;                 /* MJ checksum value read from journal */
+  u32 u;                     /* Unsigned loop counter */
+  unsigned char aMagic[8];   /* A buffer to hold the magic header */
   zMaster[0] = '\0';
 
-  rc = sqlite3OsFileSize(pJrnl, &szJ);
-  if( rc!=SQLITE_OK || szJ<16 ) return rc;
-
-  rc = read32bits(pJrnl, szJ-16, &len);
-  if( rc!=SQLITE_OK ) return rc;
-
-  if( len>=nMaster ){
-    return SQLITE_OK;
-  }
-
-  rc = read32bits(pJrnl, szJ-12, &cksum);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8);
-  if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc;
-
-  rc = sqlite3OsRead(pJrnl, zMaster, len, szJ-16-len);
-  if( rc!=SQLITE_OK ){
+  if( SQLITE_OK!=(rc = sqlite3OsFileSize(pJrnl, &szJ))
+   || szJ<16
+   || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-16, &len))
+   || len>=nMaster 
+   || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-12, &cksum))
+   || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8))
+   || memcmp(aMagic, aJournalMagic, 8)
+   || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, zMaster, len, szJ-16-len))
+  ){
     return rc;
   }
-  zMaster[len] = '\0';
 
   /* See if the checksum matches the master journal name */
   for(u=0; u<len; u++){
     cksum -= zMaster[u];
-   }
+  }
   if( cksum ){
     /* If the checksum doesn't add up, then one or more of the disk sectors
     ** containing the master journal filename is corrupted. This means
     ** definitely roll back, so just return SQLITE_OK and report a (nul)
     ** master-journal filename.
     */
-    zMaster[0] = '\0';
+    len = 0;
   }
+  zMaster[len] = '\0';
    
   return SQLITE_OK;
 }
 
 /*
-** Seek the journal file descriptor to the next sector boundary where a
-** journal header may be read or written. Pager.journalOff is updated with
-** the new seek offset.
+** Return the offset of the sector boundary at or immediately 
+** following the value in pPager->journalOff, assuming a sector 
+** size of pPager->sectorSize bytes.
 **
 ** i.e for a sector size of 512:
 **
-** Input Offset              Output Offset
-** ---------------------------------------
-** 0                         0
-** 512                       512
-** 100                       512
-** 2000                      2048
+**   Pager.journalOff          Return value
+**   ---------------------------------------
+**   0                         0
+**   512                       512
+**   100                       512
+**   2000                      2048
 ** 
 */
 static i64 journalHdrOffset(Pager *pPager){
@@ -31350,30 +38222,43 @@ static i64 journalHdrOffset(Pager *pPager){
   assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
   return offset;
 }
-static void seekJournalHdr(Pager *pPager){
-  pPager->journalOff = journalHdrOffset(pPager);
-}
 
 /*
-** Write zeros over the header of the journal file.  This has the
-** effect of invalidating the journal file and committing the
-** transaction.
+** The journal file must be open when this function is called.
+**
+** This function is a no-op if the journal file has not been written to
+** within the current transaction (i.e. if Pager.journalOff==0).
+**
+** If doTruncate is non-zero or the Pager.journalSizeLimit variable is
+** set to 0, then truncate the journal file to zero bytes in size. Otherwise,
+** zero the 28-byte header at the start of the journal file. In either case, 
+** if the pager is not in no-sync mode, sync the journal file immediately 
+** after writing or truncating it.
+**
+** If Pager.journalSizeLimit is set to a positive, non-zero value, and
+** following the truncation or zeroing described above the size of the 
+** journal file in bytes is larger than this value, then truncate the
+** journal file to Pager.journalSizeLimit bytes. The journal file does
+** not need to be synced following this operation.
+**
+** If an IO error occurs, abandon processing and return the IO error code.
+** Otherwise, return SQLITE_OK.
 */
 static int zeroJournalHdr(Pager *pPager, int doTruncate){
-  int rc = SQLITE_OK;
-  static const char zeroHdr[28] = {0};
-
+  int rc = SQLITE_OK;                               /* Return code */
+  assert( isOpen(pPager->jfd) );
   if( pPager->journalOff ){
-    i64 iLimit = pPager->journalSizeLimit;
+    const i64 iLimit = pPager->journalSizeLimit;    /* Local cache of jsl */
 
     IOTRACE(("JZEROHDR %p\n", pPager))
     if( doTruncate || iLimit==0 ){
       rc = sqlite3OsTruncate(pPager->jfd, 0);
     }else{
+      static const char zeroHdr[28] = {0};
       rc = sqlite3OsWrite(pPager->jfd, zeroHdr, sizeof(zeroHdr), 0);
     }
     if( rc==SQLITE_OK && !pPager->noSync ){
-      rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->sync_flags);
+      rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->syncFlags);
     }
 
     /* At this point the transaction is committed but the write lock 
@@ -31409,19 +38294,21 @@ static int zeroJournalHdr(Pager *pPager, int doTruncate){
 ** Followed by (JOURNAL_HDR_SZ - 28) bytes of unused space.
 */
 static int writeJournalHdr(Pager *pPager){
-  int rc = SQLITE_OK;
-  char *zHeader = pPager->pTmpSpace;
-  u32 nHeader = pPager->pageSize;
-  u32 nWrite;
-  int ii;
+  int rc = SQLITE_OK;                 /* Return code */
+  char *zHeader = pPager->pTmpSpace;  /* Temporary space used to build header */
+  u32 nHeader = (u32)pPager->pageSize;/* Size of buffer pointed to by zHeader */
+  u32 nWrite;                         /* Bytes of header sector written */
+  int ii;                             /* Loop counter */
+
+  assert( isOpen(pPager->jfd) );      /* Journal file must be open. */
 
   if( nHeader>JOURNAL_HDR_SZ(pPager) ){
     nHeader = JOURNAL_HDR_SZ(pPager);
   }
 
-  /* If there are active savepoints and any of them were created since the
-  ** most recent journal header was written, update the PagerSavepoint.iHdrOff
-  ** fields now.
+  /* If there are active savepoints and any of them were created 
+  ** since the most recent journal header was written, update the 
+  ** PagerSavepoint.iHdrOffset fields now.
   */
   for(ii=0; ii<pPager->nSavepoint; ii++){
     if( pPager->aSavepoint[ii].iHdrOffset==0 ){
@@ -31429,10 +38316,7 @@ static int writeJournalHdr(Pager *pPager){
     }
   }
 
-  seekJournalHdr(pPager);
-  pPager->journalHdr = pPager->journalOff;
-
-  memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
+  pPager->journalHdr = pPager->journalOff = journalHdrOffset(pPager);
 
   /* 
   ** Write the nRec Field - the number of page records that follow this
@@ -31444,7 +38328,7 @@ static int writeJournalHdr(Pager *pPager){
   ** A faster alternative is to write 0xFFFFFFFF to the nRec field. When
   ** reading the journal this value tells SQLite to assume that the
   ** rest of the journal file contains valid page records. This assumption
-  ** is dangerous, as if a failure occured whilst writing to the journal
+  ** is dangerous, as if a failure occurred whilst writing to the journal
   ** file it may contain some garbage data. There are two scenarios
   ** where this risk can be ignored:
   **
@@ -31454,13 +38338,14 @@ static int writeJournalHdr(Pager *pPager){
   **   * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
   **     that garbage data is never appended to the journal file.
   */
-  assert(pPager->fd->pMethods||pPager->noSync);
-  if( (pPager->noSync) || (pPager->journalMode==PAGER_JOURNALMODE_MEMORY)
+  assert( isOpen(pPager->fd) || pPager->noSync );
+  if( pPager->noSync || (pPager->journalMode==PAGER_JOURNALMODE_MEMORY)
    || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND) 
   ){
+    memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
     put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
   }else{
-    put32bits(&zHeader[sizeof(aJournalMagic)], 0);
+    memset(zHeader, 0, sizeof(aJournalMagic)+4);
   }
 
   /* The random check-hash initialiser */ 
@@ -31471,22 +38356,38 @@ static int writeJournalHdr(Pager *pPager){
   /* The assumed sector size for this process */
   put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
 
+  /* The page size */
+  put32bits(&zHeader[sizeof(aJournalMagic)+16], pPager->pageSize);
+
   /* Initializing the tail of the buffer is not necessary.  Everything
   ** works find if the following memset() is omitted.  But initializing
   ** the memory prevents valgrind from complaining, so we are willing to
   ** take the performance hit.
   */
-  memset(&zHeader[sizeof(aJournalMagic)+16], 0,
-         nHeader-(sizeof(aJournalMagic)+16));
-
-  if( pPager->journalHdr==0 ){
-    /* The page size */
-    put32bits(&zHeader[sizeof(aJournalMagic)+16], pPager->pageSize);
-  }
+  memset(&zHeader[sizeof(aJournalMagic)+20], 0,
+         nHeader-(sizeof(aJournalMagic)+20));
 
+  /* In theory, it is only necessary to write the 28 bytes that the 
+  ** journal header consumes to the journal file here. Then increment the 
+  ** Pager.journalOff variable by JOURNAL_HDR_SZ so that the next 
+  ** record is written to the following sector (leaving a gap in the file
+  ** that will be implicitly filled in by the OS).
+  **
+  ** However it has been discovered that on some systems this pattern can 
+  ** be significantly slower than contiguously writing data to the file,
+  ** even if that means explicitly writing data to the block of 
+  ** (JOURNAL_HDR_SZ - 28) bytes that will not be used. So that is what
+  ** is done. 
+  **
+  ** The loop is required here in case the sector-size is larger than the 
+  ** database page size. Since the zHeader buffer is only Pager.pageSize
+  ** bytes in size, more than one call to sqlite3OsWrite() may be required
+  ** to populate the entire journal header sector.
+  */ 
   for(nWrite=0; rc==SQLITE_OK&&nWrite<JOURNAL_HDR_SZ(pPager); nWrite+=nHeader){
     IOTRACE(("JHDR %p %lld %d\n", pPager, pPager->journalHdr, nHeader))
     rc = sqlite3OsWrite(pPager->jfd, zHeader, nHeader, pPager->journalOff);
+    assert( pPager->journalHdr <= pPager->journalOff );
     pPager->journalOff += nHeader;
   }
 
@@ -31497,93 +38398,122 @@ static int writeJournalHdr(Pager *pPager){
 ** The journal file must be open when this is called. A journal header file
 ** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
 ** file. The current location in the journal file is given by
-** pPager->journalOff.  See comments above function writeJournalHdr() for
+** pPager->journalOff. See comments above function writeJournalHdr() for
 ** a description of the journal header format.
 **
-** If the header is read successfully, *nRec is set to the number of
-** page records following this header and *dbSize is set to the size of the
+** If the header is read successfully, *pNRec is set to the number of
+** page records following this header and *pDbSize is set to the size of the
 ** database before the transaction began, in pages. Also, pPager->cksumInit
 ** is set to the value read from the journal header. SQLITE_OK is returned
 ** in this case.
 **
 ** If the journal header file appears to be corrupted, SQLITE_DONE is
-** returned and *nRec and *dbSize are undefined.  If JOURNAL_HDR_SZ bytes
+** returned and *pNRec and *PDbSize are undefined.  If JOURNAL_HDR_SZ bytes
 ** cannot be read from the journal file an error code is returned.
 */
 static int readJournalHdr(
-  Pager *pPager, 
-  i64 journalSize,
-  u32 *pNRec, 
-  u32 *pDbSize
+  Pager *pPager,               /* Pager object */
+  int isHot,
+  i64 journalSize,             /* Size of the open journal file in bytes */
+  u32 *pNRec,                  /* OUT: Value read from the nRec field */
+  u32 *pDbSize                 /* OUT: Value of original database size field */
 ){
-  int rc;
-  unsigned char aMagic[8]; /* A buffer to hold the magic header */
-  i64 jrnlOff;
-  u32 iPageSize;
-  u32 iSectorSize;
+  int rc;                      /* Return code */
+  unsigned char aMagic[8];     /* A buffer to hold the magic header */
+  i64 iHdrOff;                 /* Offset of journal header being read */
 
-  seekJournalHdr(pPager);
+  assert( isOpen(pPager->jfd) );      /* Journal file must be open. */
+
+  /* Advance Pager.journalOff to the start of the next sector. If the
+  ** journal file is too small for there to be a header stored at this
+  ** point, return SQLITE_DONE.
+  */
+  pPager->journalOff = journalHdrOffset(pPager);
   if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
     return SQLITE_DONE;
   }
-  jrnlOff = pPager->journalOff;
+  iHdrOff = pPager->journalOff;
 
-  rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), jrnlOff);
-  if( rc ) return rc;
-  jrnlOff += sizeof(aMagic);
-
-  if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
-    return SQLITE_DONE;
+  /* Read in the first 8 bytes of the journal header. If they do not match
+  ** the  magic string found at the start of each journal header, return
+  ** SQLITE_DONE. If an IO error occurs, return an error code. Otherwise,
+  ** proceed.
+  */
+  if( isHot || iHdrOff!=pPager->journalHdr ){
+    rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), iHdrOff);
+    if( rc ){
+      return rc;
+    }
+    if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
+      return SQLITE_DONE;
+    }
   }
 
-  rc = read32bits(pPager->jfd, jrnlOff, pNRec);
-  if( rc ) return rc;
-
-  rc = read32bits(pPager->jfd, jrnlOff+4, &pPager->cksumInit);
-  if( rc ) return rc;
-
-  rc = read32bits(pPager->jfd, jrnlOff+8, pDbSize);
-  if( rc ) return rc;
+  /* Read the first three 32-bit fields of the journal header: The nRec
+  ** field, the checksum-initializer and the database size at the start
+  ** of the transaction. Return an error code if anything goes wrong.
+  */
+  if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+8, pNRec))
+   || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+12, &pPager->cksumInit))
+   || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+16, pDbSize))
+  ){
+    return rc;
+  }
 
   if( pPager->journalOff==0 ){
-    rc = read32bits(pPager->jfd, jrnlOff+16, &iPageSize);
-    if( rc ) return rc;
+    u32 iPageSize;               /* Page-size field of journal header */
+    u32 iSectorSize;             /* Sector-size field of journal header */
 
-    if( iPageSize<512 
-     || iPageSize>SQLITE_MAX_PAGE_SIZE 
-     || ((iPageSize-1)&iPageSize)!=0 
+    /* Read the page-size and sector-size journal header fields. */
+    if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+20, &iSectorSize))
+     || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+24, &iPageSize))
     ){
-      /* If the page-size in the journal-header is invalid, then the process
-      ** that wrote the journal-header must have crashed before the header
-      ** was synced. In this case stop reading the journal file here.
-      */
-      rc = SQLITE_DONE;
-    }else{
-      u16 pagesize = (u16)iPageSize;
-      rc = sqlite3PagerSetPagesize(pPager, &pagesize);
-      assert( rc!=SQLITE_OK || pagesize==(u16)iPageSize );
+      return rc;
     }
-    if( rc ) return rc;
-  
+
+    /* Versions of SQLite prior to 3.5.8 set the page-size field of the
+    ** journal header to zero. In this case, assume that the Pager.pageSize
+    ** variable is already set to the correct page size.
+    */
+    if( iPageSize==0 ){
+      iPageSize = pPager->pageSize;
+    }
+
+    /* Check that the values read from the page-size and sector-size fields
+    ** are within range. To be 'in range', both values need to be a power
+    ** of two greater than or equal to 512 or 32, and not greater than their 
+    ** respective compile time maximum limits.
+    */
+    if( iPageSize<512                  || iSectorSize<32
+     || iPageSize>SQLITE_MAX_PAGE_SIZE || iSectorSize>MAX_SECTOR_SIZE
+     || ((iPageSize-1)&iPageSize)!=0   || ((iSectorSize-1)&iSectorSize)!=0 
+    ){
+      /* If the either the page-size or sector-size in the journal-header is 
+      ** invalid, then the process that wrote the journal-header must have 
+      ** crashed before the header was synced. In this case stop reading 
+      ** the journal file here.
+      */
+      return SQLITE_DONE;
+    }
+
+    /* Update the page-size to match the value read from the journal. 
+    ** Use a testcase() macro to make sure that malloc failure within 
+    ** PagerSetPagesize() is tested.
+    */
+    rc = sqlite3PagerSetPagesize(pPager, &iPageSize, -1);
+    testcase( rc!=SQLITE_OK );
+
     /* Update the assumed sector-size to match the value used by 
     ** the process that created this journal. If this journal was
     ** created by a process other than this one, then this routine
     ** is being called from within pager_playback(). The local value
     ** of Pager.sectorSize is restored at the end of that routine.
     */
-    rc = read32bits(pPager->jfd, jrnlOff+12, &iSectorSize);
-    if( rc ) return rc;
-    if( (iSectorSize&(iSectorSize-1))
-      || iSectorSize<512
-      || iSectorSize>MAX_SECTOR_SIZE
-    ){
-      return SQLITE_DONE;
-    }
     pPager->sectorSize = iSectorSize;
   }
 
   pPager->journalOff += JOURNAL_HDR_SZ(pPager);
-  return SQLITE_OK;
+  return rc;
 }
 
 
@@ -31594,34 +38524,41 @@ static int readJournalHdr(
 ** journal file descriptor is advanced to the next sector boundary before
 ** anything is written. The format is:
 **
-** + 4 bytes: PAGER_MJ_PGNO.
-** + N bytes: length of master journal name.
-** + 4 bytes: N
-** + 4 bytes: Master journal name checksum.
-** + 8 bytes: aJournalMagic[].
+**   + 4 bytes: PAGER_MJ_PGNO.
+**   + N bytes: Master journal filename in utf-8.
+**   + 4 bytes: N (length of master journal name in bytes, no nul-terminator).
+**   + 4 bytes: Master journal name checksum.
+**   + 8 bytes: aJournalMagic[].
 **
 ** The master journal page checksum is the sum of the bytes in the master
-** journal name.
+** journal name, where each byte is interpreted as a signed 8-bit integer.
 **
 ** If zMaster is a NULL pointer (occurs for a single database transaction), 
 ** this call is a no-op.
 */
 static int writeMasterJournal(Pager *pPager, const char *zMaster){
-  int rc;
-  int len; 
-  int i; 
-  i64 jrnlOff;
-  i64 jrnlSize;
-  u32 cksum = 0;
-  char zBuf[sizeof(aJournalMagic)+2*4];
+  int rc;                          /* Return code */
+  int nMaster;                     /* Length of string zMaster */
+  i64 iHdrOff;                     /* Offset of header in journal file */
+  i64 jrnlSize;                    /* Size of journal file on disk */
+  u32 cksum = 0;                   /* Checksum of string zMaster */
 
-  if( !zMaster || pPager->setMaster ) return SQLITE_OK;
-  if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ) return SQLITE_OK;
+  assert( pPager->setMaster==0 );
+  assert( !pagerUseWal(pPager) );
+
+  if( !zMaster 
+   || pPager->journalMode==PAGER_JOURNALMODE_MEMORY 
+   || pPager->journalMode==PAGER_JOURNALMODE_OFF 
+  ){
+    return SQLITE_OK;
+  }
   pPager->setMaster = 1;
+  assert( isOpen(pPager->jfd) );
+  assert( pPager->journalHdr <= pPager->journalOff );
 
-  len = sqlite3Strlen30(zMaster);
-  for(i=0; i<len; i++){
-    cksum += zMaster[i];
+  /* Calculate the length in bytes and the checksum of zMaster */
+  for(nMaster=0; zMaster[nMaster]; nMaster++){
+    cksum += zMaster[nMaster];
   }
 
   /* If in full-sync mode, advance to the next disk sector before writing
@@ -31629,25 +38566,22 @@ static int writeMasterJournal(Pager *pPager, const char *zMaster){
   ** the journal has already been synced.
   */
   if( pPager->fullSync ){
-    seekJournalHdr(pPager);
+    pPager->journalOff = journalHdrOffset(pPager);
   }
-  jrnlOff = pPager->journalOff;
-  pPager->journalOff += (len+20);
+  iHdrOff = pPager->journalOff;
 
-  rc = write32bits(pPager->jfd, jrnlOff, PAGER_MJ_PGNO(pPager));
-  if( rc!=SQLITE_OK ) return rc;
-  jrnlOff += 4;
-
-  rc = sqlite3OsWrite(pPager->jfd, zMaster, len, jrnlOff);
-  if( rc!=SQLITE_OK ) return rc;
-  jrnlOff += len;
-
-  put32bits(zBuf, len);
-  put32bits(&zBuf[4], cksum);
-  memcpy(&zBuf[8], aJournalMagic, sizeof(aJournalMagic));
-  rc = sqlite3OsWrite(pPager->jfd, zBuf, 8+sizeof(aJournalMagic), jrnlOff);
-  jrnlOff += 8+sizeof(aJournalMagic);
-  pPager->needSync = !pPager->noSync;
+  /* Write the master journal data to the end of the journal file. If
+  ** an error occurs, return the error code to the caller.
+  */
+  if( (0 != (rc = write32bits(pPager->jfd, iHdrOff, PAGER_MJ_PGNO(pPager))))
+   || (0 != (rc = sqlite3OsWrite(pPager->jfd, zMaster, nMaster, iHdrOff+4)))
+   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster, nMaster)))
+   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster+4, cksum)))
+   || (0 != (rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, 8, iHdrOff+4+nMaster+8)))
+  ){
+    return rc;
+  }
+  pPager->journalOff += (nMaster+20);
 
   /* If the pager is in peristent-journal mode, then the physical 
   ** journal-file may extend past the end of the master-journal name
@@ -31659,33 +38593,34 @@ static int writeMasterJournal(Pager *pPager, const char *zMaster){
   ** Easiest thing to do in this scenario is to truncate the journal 
   ** file to the required size.
   */ 
-  if( (rc==SQLITE_OK)
-   && (rc = sqlite3OsFileSize(pPager->jfd, &jrnlSize))==SQLITE_OK
-   && jrnlSize>jrnlOff
+  if( SQLITE_OK==(rc = sqlite3OsFileSize(pPager->jfd, &jrnlSize))
+   && jrnlSize>pPager->journalOff
   ){
-    rc = sqlite3OsTruncate(pPager->jfd, jrnlOff);
+    rc = sqlite3OsTruncate(pPager->jfd, pPager->journalOff);
   }
   return rc;
 }
 
 /*
-** Find a page in the hash table given its page number.  Return
-** a pointer to the page or NULL if not found.
+** Find a page in the hash table given its page number. Return
+** a pointer to the page or NULL if the requested page is not 
+** already in memory.
 */
 static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
-  PgHdr *p;
-  sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &p);
+  PgHdr *p;                         /* Return value */
+
+  /* It is not possible for a call to PcacheFetch() with createFlag==0 to
+  ** fail, since no attempt to allocate dynamic memory will be made.
+  */
+  (void)sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &p);
   return p;
 }
 
 /*
-** Clear the in-memory cache.  This routine
-** sets the state of the pager back to what it was when it was first
-** opened.  Any outstanding pages are invalidated and subsequent attempts
-** to access those pages will likely result in a coredump.
+** Discard the entire contents of the in-memory page-cache.
 */
 static void pager_reset(Pager *pPager){
-  if( pPager->errCode ) return;
+  sqlite3BackupRestart(pPager->pBackup);
   sqlite3PcacheClear(pPager->pPCache);
 }
 
@@ -31694,23 +38629,24 @@ static void pager_reset(Pager *pPager){
 ** Pager.aSavepoint and Pager.nSavepoint to zero. Close the sub-journal
 ** if it is open and the pager is not in exclusive mode.
 */
-static void releaseAllSavepoint(Pager *pPager){
-  int ii;
+static void releaseAllSavepoints(Pager *pPager){
+  int ii;               /* Iterator for looping through Pager.aSavepoint */
   for(ii=0; ii<pPager->nSavepoint; ii++){
     sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
   }
-  if( !pPager->exclusiveMode ){
+  if( !pPager->exclusiveMode || sqlite3IsMemJournal(pPager->sjfd) ){
     sqlite3OsClose(pPager->sjfd);
   }
   sqlite3_free(pPager->aSavepoint);
   pPager->aSavepoint = 0;
   pPager->nSavepoint = 0;
-  pPager->stmtNRec = 0;
+  pPager->nSubRec = 0;
 }
 
 /*
-** Set the bit number pgno in the PagerSavepoint.pInSavepoint bitvecs of
-** all open savepoints.
+** Set the bit number pgno in the PagerSavepoint.pInSavepoint 
+** bitvecs of all open savepoints. Return SQLITE_OK if successful
+** or SQLITE_NOMEM if a malloc failure occurs.
 */
 static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
   int ii;                   /* Loop counter */
@@ -31720,6 +38656,7 @@ static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
     PagerSavepoint *p = &pPager->aSavepoint[ii];
     if( pgno<=p->nOrig ){
       rc |= sqlite3BitvecSet(p->pInSavepoint, pgno);
+      testcase( rc==SQLITE_NOMEM );
       assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
     }
   }
@@ -31727,176 +38664,334 @@ static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
 }
 
 /*
-** Unlock the database file. 
+** This function is a no-op if the pager is in exclusive mode and not
+** in the ERROR state. Otherwise, it switches the pager to PAGER_OPEN
+** state.
 **
-** If the pager is currently in error state, discard the contents of 
-** the cache and reset the Pager structure internal state. If there is
-** an open journal-file, then the next time a shared-lock is obtained
-** on the pager file (by this or any other process), it will be
-** treated as a hot-journal and rolled back.
+** If the pager is not in exclusive-access mode, the database file is
+** completely unlocked. If the file is unlocked and the file-system does
+** not exhibit the UNDELETABLE_WHEN_OPEN property, the journal file is
+** closed (if it is open).
+**
+** If the pager is in ERROR state when this function is called, the 
+** contents of the pager cache are discarded before switching back to 
+** the OPEN state. Regardless of whether the pager is in exclusive-mode
+** or not, any journal file left in the file-system will be treated
+** as a hot-journal and rolled back the next time a read-transaction
+** is opened (by this or by any other connection).
 */
 static void pager_unlock(Pager *pPager){
-  if( !pPager->exclusiveMode ){
-    int rc;
 
-    /* Always close the journal file when dropping the database lock.
-    ** Otherwise, another connection with journal_mode=delete might
-    ** delete the file out from under us.
+  assert( pPager->eState==PAGER_READER 
+       || pPager->eState==PAGER_OPEN 
+       || pPager->eState==PAGER_ERROR 
+  );
+
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  pPager->pInJournal = 0;
+  releaseAllSavepoints(pPager);
+
+  if( pagerUseWal(pPager) ){
+    assert( !isOpen(pPager->jfd) );
+    sqlite3WalEndReadTransaction(pPager->pWal);
+    pPager->eState = PAGER_OPEN;
+  }else if( !pPager->exclusiveMode ){
+    int rc;                       /* Error code returned by pagerUnlockDb() */
+    int iDc = isOpen(pPager->fd)?sqlite3OsDeviceCharacteristics(pPager->fd):0;
+
+    /* If the operating system support deletion of open files, then
+    ** close the journal file when dropping the database lock.  Otherwise
+    ** another connection with journal_mode=delete might delete the file
+    ** out from under us.
     */
-    if( pPager->journalOpen ){
+    assert( (PAGER_JOURNALMODE_MEMORY   & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_OFF      & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_WAL      & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_DELETE   & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
+    assert( (PAGER_JOURNALMODE_PERSIST  & 5)==1 );
+    if( 0==(iDc & SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN)
+     || 1!=(pPager->journalMode & 5)
+    ){
       sqlite3OsClose(pPager->jfd);
-      pPager->journalOpen = 0;
-      sqlite3BitvecDestroy(pPager->pInJournal);
-      pPager->pInJournal = 0;
-      sqlite3BitvecDestroy(pPager->pAlwaysRollback);
-      pPager->pAlwaysRollback = 0;
     }
 
-    rc = osUnlock(pPager->fd, NO_LOCK);
-    if( rc ) pPager->errCode = rc;
-    pPager->dbSizeValid = 0;
-    IOTRACE(("UNLOCK %p\n", pPager))
-
-    /* If Pager.errCode is set, the contents of the pager cache cannot be
-    ** trusted. Now that the pager file is unlocked, the contents of the
-    ** cache can be discarded and the error code safely cleared.
+    /* If the pager is in the ERROR state and the call to unlock the database
+    ** file fails, set the current lock to UNKNOWN_LOCK. See the comment
+    ** above the #define for UNKNOWN_LOCK for an explanation of why this
+    ** is necessary.
     */
-    if( pPager->errCode ){
-      if( rc==SQLITE_OK ) pPager->errCode = SQLITE_OK;
-      pager_reset(pPager);
-      releaseAllSavepoint(pPager);
-      pPager->journalOff = 0;
-      pPager->journalStarted = 0;
-      pPager->dbOrigSize = 0;
+    rc = pagerUnlockDb(pPager, NO_LOCK);
+    if( rc!=SQLITE_OK && pPager->eState==PAGER_ERROR ){
+      pPager->eLock = UNKNOWN_LOCK;
     }
 
-    pPager->state = PAGER_UNLOCK;
+    /* The pager state may be changed from PAGER_ERROR to PAGER_OPEN here
+    ** without clearing the error code. This is intentional - the error
+    ** code is cleared and the cache reset in the block below.
+    */
+    assert( pPager->errCode || pPager->eState!=PAGER_ERROR );
     pPager->changeCountDone = 0;
+    pPager->eState = PAGER_OPEN;
   }
+
+  /* If Pager.errCode is set, the contents of the pager cache cannot be
+  ** trusted. Now that there are no outstanding references to the pager,
+  ** it can safely move back to PAGER_OPEN state. This happens in both
+  ** normal and exclusive-locking mode.
+  */
+  if( pPager->errCode ){
+    assert( !MEMDB );
+    pager_reset(pPager);
+    pPager->changeCountDone = pPager->tempFile;
+    pPager->eState = PAGER_OPEN;
+    pPager->errCode = SQLITE_OK;
+  }
+
+  pPager->journalOff = 0;
+  pPager->journalHdr = 0;
+  pPager->setMaster = 0;
 }
 
 /*
-** Execute a rollback if a transaction is active and unlock the 
-** database file. If the pager has already entered the error state, 
-** do not attempt the rollback.
+** This function is called whenever an IOERR or FULL error that requires
+** the pager to transition into the ERROR state may ahve occurred.
+** The first argument is a pointer to the pager structure, the second 
+** the error-code about to be returned by a pager API function. The 
+** value returned is a copy of the second argument to this function. 
+**
+** If the second argument is SQLITE_FULL, SQLITE_IOERR or one of the
+** IOERR sub-codes, the pager enters the ERROR state and the error code
+** is stored in Pager.errCode. While the pager remains in the ERROR state,
+** all major API calls on the Pager will immediately return Pager.errCode.
+**
+** The ERROR state indicates that the contents of the pager-cache 
+** cannot be trusted. This state can be cleared by completely discarding 
+** the contents of the pager-cache. If a transaction was active when
+** the persistent error occurred, then the rollback journal may need
+** to be replayed to restore the contents of the database file (as if
+** it were a hot-journal).
 */
-static void pagerUnlockAndRollback(Pager *p){
-  if( p->errCode==SQLITE_OK && p->state>=PAGER_RESERVED ){
-    sqlite3BeginBenignMalloc();
-    sqlite3PagerRollback(p);
-    sqlite3EndBenignMalloc();
+static int pager_error(Pager *pPager, int rc){
+  int rc2 = rc & 0xff;
+  assert( rc==SQLITE_OK || !MEMDB );
+  assert(
+       pPager->errCode==SQLITE_FULL ||
+       pPager->errCode==SQLITE_OK ||
+       (pPager->errCode & 0xff)==SQLITE_IOERR
+  );
+  if( rc2==SQLITE_FULL || rc2==SQLITE_IOERR ){
+    pPager->errCode = rc;
+    pPager->eState = PAGER_ERROR;
   }
-  pager_unlock(p);
+  return rc;
 }
 
 /*
-** This routine ends a transaction.  A transaction is ended by either
-** a COMMIT or a ROLLBACK.
+** This routine ends a transaction. A transaction is usually ended by 
+** either a COMMIT or a ROLLBACK operation. This routine may be called 
+** after rollback of a hot-journal, or if an error occurs while opening
+** the journal file or writing the very first journal-header of a
+** database transaction.
+** 
+** This routine is never called in PAGER_ERROR state. If it is called
+** in PAGER_NONE or PAGER_SHARED state and the lock held is less
+** exclusive than a RESERVED lock, it is a no-op.
 **
-** When this routine is called, the pager has the journal file open and
-** a RESERVED or EXCLUSIVE lock on the database.  This routine will release
-** the database lock and acquires a SHARED lock in its place if that is
-** the appropriate thing to do.  Release locks usually is appropriate,
-** unless we are in exclusive access mode or unless this is a 
-** COMMIT AND BEGIN or ROLLBACK AND BEGIN operation.
+** Otherwise, any active savepoints are released.
 **
-** The journal file is either deleted or truncated.
+** If the journal file is open, then it is "finalized". Once a journal 
+** file has been finalized it is not possible to use it to roll back a 
+** transaction. Nor will it be considered to be a hot-journal by this
+** or any other database connection. Exactly how a journal is finalized
+** depends on whether or not the pager is running in exclusive mode and
+** the current journal-mode (Pager.journalMode value), as follows:
 **
-** TODO: Consider keeping the journal file open for temporary databases.
-** This might give a performance improvement on windows where opening
-** a file is an expensive operation.
+**   journalMode==MEMORY
+**     Journal file descriptor is simply closed. This destroys an 
+**     in-memory journal.
+**
+**   journalMode==TRUNCATE
+**     Journal file is truncated to zero bytes in size.
+**
+**   journalMode==PERSIST
+**     The first 28 bytes of the journal file are zeroed. This invalidates
+**     the first journal header in the file, and hence the entire journal
+**     file. An invalid journal file cannot be rolled back.
+**
+**   journalMode==DELETE
+**     The journal file is closed and deleted using sqlite3OsDelete().
+**
+**     If the pager is running in exclusive mode, this method of finalizing
+**     the journal file is never used. Instead, if the journalMode is
+**     DELETE and the pager is in exclusive mode, the method described under
+**     journalMode==PERSIST is used instead.
+**
+** After the journal is finalized, the pager moves to PAGER_READER state.
+** If running in non-exclusive rollback mode, the lock on the file is 
+** downgraded to a SHARED_LOCK.
+**
+** SQLITE_OK is returned if no error occurs. If an error occurs during
+** any of the IO operations to finalize the journal file or unlock the
+** database then the IO error code is returned to the user. If the 
+** operation to finalize the journal file fails, then the code still
+** tries to unlock the database file if not in exclusive mode. If the
+** unlock operation fails as well, then the first error code related
+** to the first error encountered (the journal finalization one) is
+** returned.
 */
 static int pager_end_transaction(Pager *pPager, int hasMaster){
-  int rc = SQLITE_OK;
-  int rc2 = SQLITE_OK;
-  if( pPager->state<PAGER_RESERVED ){
+  int rc = SQLITE_OK;      /* Error code from journal finalization operation */
+  int rc2 = SQLITE_OK;     /* Error code from db file unlock operation */
+
+  /* Do nothing if the pager does not have an open write transaction
+  ** or at least a RESERVED lock. This function may be called when there
+  ** is no write-transaction active but a RESERVED or greater lock is
+  ** held under two circumstances:
+  **
+  **   1. After a successful hot-journal rollback, it is called with
+  **      eState==PAGER_NONE and eLock==EXCLUSIVE_LOCK.
+  **
+  **   2. If a connection with locking_mode=exclusive holding an EXCLUSIVE 
+  **      lock switches back to locking_mode=normal and then executes a
+  **      read-transaction, this function is called with eState==PAGER_READER 
+  **      and eLock==EXCLUSIVE_LOCK when the read-transaction is closed.
+  */
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState!=PAGER_ERROR );
+  if( pPager->eState<PAGER_WRITER_LOCKED && pPager->eLock<RESERVED_LOCK ){
     return SQLITE_OK;
   }
-  releaseAllSavepoint(pPager);
-  if( pPager->journalOpen ){
-    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
-      int isMemoryJournal = sqlite3IsMemJournal(pPager->jfd);
+
+  releaseAllSavepoints(pPager);
+  assert( isOpen(pPager->jfd) || pPager->pInJournal==0 );
+  if( isOpen(pPager->jfd) ){
+    assert( !pagerUseWal(pPager) );
+
+    /* Finalize the journal file. */
+    if( sqlite3IsMemJournal(pPager->jfd) ){
+      assert( pPager->journalMode==PAGER_JOURNALMODE_MEMORY );
       sqlite3OsClose(pPager->jfd);
-      pPager->journalOpen = 0;
-      if( !isMemoryJournal ){
-        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+    }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE ){
+      if( pPager->journalOff==0 ){
+        rc = SQLITE_OK;
+      }else{
+        rc = sqlite3OsTruncate(pPager->jfd, 0);
       }
-    }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE
-         && (rc = sqlite3OsTruncate(pPager->jfd, 0))==SQLITE_OK ){
       pPager->journalOff = 0;
-      pPager->journalStarted = 0;
-    }else if( pPager->exclusiveMode 
-     || pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+      || (pPager->exclusiveMode && pPager->journalMode!=PAGER_JOURNALMODE_WAL)
     ){
       rc = zeroJournalHdr(pPager, hasMaster);
-      pager_error(pPager, rc);
       pPager->journalOff = 0;
-      pPager->journalStarted = 0;
     }else{
-      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE || rc );
+      /* This branch may be executed with Pager.journalMode==MEMORY if
+      ** a hot-journal was just rolled back. In this case the journal
+      ** file should be closed and deleted. If this connection writes to
+      ** the database file, it will do so using an in-memory journal. 
+      */
+      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE 
+           || pPager->journalMode==PAGER_JOURNALMODE_MEMORY 
+           || pPager->journalMode==PAGER_JOURNALMODE_WAL 
+      );
       sqlite3OsClose(pPager->jfd);
-      pPager->journalOpen = 0;
-      if( rc==SQLITE_OK && !pPager->tempFile ){
+      if( !pPager->tempFile ){
         rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
       }
     }
-    sqlite3BitvecDestroy(pPager->pInJournal);
-    pPager->pInJournal = 0;
-    sqlite3BitvecDestroy(pPager->pAlwaysRollback);
-    pPager->pAlwaysRollback = 0;
-#ifdef SQLITE_CHECK_PAGES
-    sqlite3PcacheIterateDirty(pPager->pPCache, pager_set_pagehash);
-#endif
-    sqlite3PcacheCleanAll(pPager->pPCache);
-    pPager->dirtyCache = 0;
-    pPager->nRec = 0;
-  }else{
-    assert( pPager->pInJournal==0 );
   }
 
-  if( !pPager->exclusiveMode ){
-    rc2 = osUnlock(pPager->fd, SHARED_LOCK);
-    pPager->state = PAGER_SHARED;
-    pPager->changeCountDone = 0;
-  }else if( pPager->state==PAGER_SYNCED ){
-    pPager->state = PAGER_EXCLUSIVE;
+#ifdef SQLITE_CHECK_PAGES
+  sqlite3PcacheIterateDirty(pPager->pPCache, pager_set_pagehash);
+  if( pPager->dbSize==0 && sqlite3PcacheRefCount(pPager->pPCache)>0 ){
+    PgHdr *p = pager_lookup(pPager, 1);
+    if( p ){
+      p->pageHash = 0;
+      sqlite3PagerUnref(p);
+    }
   }
-  pPager->dbOrigSize = 0;
-  pPager->setMaster = 0;
-  pPager->needSync = 0;
-  /* lruListSetFirstSynced(pPager); */
+#endif
+
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  pPager->pInJournal = 0;
+  pPager->nRec = 0;
+  sqlite3PcacheCleanAll(pPager->pPCache);
   sqlite3PcacheTruncate(pPager->pPCache, pPager->dbSize);
-  if( !MEMDB ){
-    pPager->dbSizeValid = 0;
+
+  if( pagerUseWal(pPager) ){
+    /* Drop the WAL write-lock, if any. Also, if the connection was in 
+    ** locking_mode=exclusive mode but is no longer, drop the EXCLUSIVE 
+    ** lock held on the database file.
+    */
+    rc2 = sqlite3WalEndWriteTransaction(pPager->pWal);
+    assert( rc2==SQLITE_OK );
   }
-  pPager->dbModified = 0;
+  if( !pPager->exclusiveMode 
+   && (!pagerUseWal(pPager) || sqlite3WalExclusiveMode(pPager->pWal, 0))
+  ){
+    rc2 = pagerUnlockDb(pPager, SHARED_LOCK);
+    pPager->changeCountDone = 0;
+  }
+  pPager->eState = PAGER_READER;
+  pPager->setMaster = 0;
 
   return (rc==SQLITE_OK?rc2:rc);
 }
 
 /*
-** Compute and return a checksum for the page of data.
+** Execute a rollback if a transaction is active and unlock the 
+** database file. 
 **
-** This is not a real checksum.  It is really just the sum of the 
-** random initial value and the page number.  We experimented with
-** a checksum of the entire data, but that was found to be too slow.
+** If the pager has already entered the ERROR state, do not attempt 
+** the rollback at this time. Instead, pager_unlock() is called. The
+** call to pager_unlock() will discard all in-memory pages, unlock
+** the database file and move the pager back to OPEN state. If this 
+** means that there is a hot-journal left in the file-system, the next 
+** connection to obtain a shared lock on the pager (which may be this one) 
+** will roll it back.
 **
-** Note that the page number is stored at the beginning of data and
-** the checksum is stored at the end.  This is important.  If journal
-** corruption occurs due to a power failure, the most likely scenario
-** is that one end or the other of the record will be changed.  It is
-** much less likely that the two ends of the journal record will be
+** If the pager has not already entered the ERROR state, but an IO or
+** malloc error occurs during a rollback, then this will itself cause 
+** the pager to enter the ERROR state. Which will be cleared by the
+** call to pager_unlock(), as described above.
+*/
+static void pagerUnlockAndRollback(Pager *pPager){
+  if( pPager->eState!=PAGER_ERROR && pPager->eState!=PAGER_OPEN ){
+    assert( assert_pager_state(pPager) );
+    if( pPager->eState>=PAGER_WRITER_LOCKED ){
+      sqlite3BeginBenignMalloc();
+      sqlite3PagerRollback(pPager);
+      sqlite3EndBenignMalloc();
+    }else if( !pPager->exclusiveMode ){
+      assert( pPager->eState==PAGER_READER );
+      pager_end_transaction(pPager, 0);
+    }
+  }
+  pager_unlock(pPager);
+}
+
+/*
+** Parameter aData must point to a buffer of pPager->pageSize bytes
+** of data. Compute and return a checksum based ont the contents of the 
+** page of data and the current value of pPager->cksumInit.
+**
+** This is not a real checksum. It is really just the sum of the 
+** random initial value (pPager->cksumInit) and every 200th byte
+** of the page data, starting with byte offset (pPager->pageSize%200).
+** Each byte is interpreted as an 8-bit unsigned integer.
+**
+** Changing the formula used to compute this checksum results in an
+** incompatible journal file format.
+**
+** If journal corruption occurs due to a power failure, the most likely 
+** scenario is that one end or the other of the record will be changed. 
+** It is much less likely that the two ends of the journal record will be
 ** correct and the middle be corrupt.  Thus, this "checksum" scheme,
 ** though fast and simple, catches the mostly likely kind of corruption.
-**
-** FIX ME:  Consider adding every 200th (or so) byte of the data to the
-** checksum.  That way if a single page spans 3 or more disk sectors and
-** only the middle sector is corrupt, we will still have a reasonable
-** chance of failing the checksum and thus detecting the problem.
 */
 static u32 pager_cksum(Pager *pPager, const u8 *aData){
-  u32 cksum = pPager->cksumInit;
-  int i = pPager->pageSize-200;
+  u32 cksum = pPager->cksumInit;         /* Checksum value to return */
+  int i = pPager->pageSize-200;          /* Loop counter */
   while( i>0 ){
     cksum += aData[i];
     i -= 200;
@@ -31904,49 +38999,100 @@ static u32 pager_cksum(Pager *pPager, const u8 *aData){
   return cksum;
 }
 
+/*
+** Report the current page size and number of reserved bytes back
+** to the codec.
+*/
+#ifdef SQLITE_HAS_CODEC
+static void pagerReportSize(Pager *pPager){
+  if( pPager->xCodecSizeChng ){
+    pPager->xCodecSizeChng(pPager->pCodec, pPager->pageSize,
+                           (int)pPager->nReserve);
+  }
+}
+#else
+# define pagerReportSize(X)     /* No-op if we do not support a codec */
+#endif
+
 /*
 ** Read a single page from either the journal file (if isMainJrnl==1) or
 ** from the sub-journal (if isMainJrnl==0) and playback that page.
-** The page begins at offset *pOffset into the file.  The  *pOffset
+** The page begins at offset *pOffset into the file. The *pOffset
 ** value is increased to the start of the next page in the journal.
 **
-** The isMainJrnl flag is true if this is the main rollback journal and
-** false for the statement journal.  The main rollback journal uses
-** checksums - the statement journal does not.
+** The main rollback journal uses checksums - the statement journal does 
+** not.
+**
+** If the page number of the page record read from the (sub-)journal file
+** is greater than the current value of Pager.dbSize, then playback is
+** skipped and SQLITE_OK is returned.
 **
 ** If pDone is not NULL, then it is a record of pages that have already
 ** been played back.  If the page at *pOffset has already been played back
 ** (if the corresponding pDone bit is set) then skip the playback.
 ** Make sure the pDone bit corresponding to the *pOffset page is set
 ** prior to returning.
+**
+** If the page record is successfully read from the (sub-)journal file
+** and played back, then SQLITE_OK is returned. If an IO error occurs
+** while reading the record from the (sub-)journal file or while writing
+** to the database file, then the IO error code is returned. If data
+** is successfully read from the (sub-)journal file but appears to be
+** corrupted, SQLITE_DONE is returned. Data is considered corrupted in
+** two circumstances:
+** 
+**   * If the record page-number is illegal (0 or PAGER_MJ_PGNO), or
+**   * If the record is being rolled back from the main journal file
+**     and the checksum field does not match the record content.
+**
+** Neither of these two scenarios are possible during a savepoint rollback.
+**
+** If this is a savepoint rollback, then memory may have to be dynamically
+** allocated by this function. If this is the case and an allocation fails,
+** SQLITE_NOMEM is returned.
 */
 static int pager_playback_one_page(
   Pager *pPager,                /* The pager being played back */
-  int isMainJrnl,               /* 1 -> main journal. 0 -> sub-journal. */
   i64 *pOffset,                 /* Offset of record to playback */
-  int isSavepnt,                /* True for a savepoint rollback */
-  Bitvec *pDone                 /* Bitvec of pages already played back */
+  Bitvec *pDone,                /* Bitvec of pages already played back */
+  int isMainJrnl,               /* 1 -> main journal. 0 -> sub-journal. */
+  int isSavepnt                 /* True for a savepoint rollback */
 ){
   int rc;
   PgHdr *pPg;                   /* An existing page in the cache */
   Pgno pgno;                    /* The page number of a page in journal */
   u32 cksum;                    /* Checksum used for sanity checking */
-  u8 *aData;                    /* Temporary storage for the page */
+  char *aData;                  /* Temporary storage for the page */
   sqlite3_file *jfd;            /* The file descriptor for the journal file */
+  int isSynced;                 /* True if journal page is synced */
 
   assert( (isMainJrnl&~1)==0 );      /* isMainJrnl is 0 or 1 */
   assert( (isSavepnt&~1)==0 );       /* isSavepnt is 0 or 1 */
   assert( isMainJrnl || pDone );     /* pDone always used on sub-journals */
   assert( isSavepnt || pDone==0 );   /* pDone never used on non-savepoint */
 
-  aData = (u8*)pPager->pTmpSpace;
+  aData = pPager->pTmpSpace;
   assert( aData );         /* Temp storage must have already been allocated */
+  assert( pagerUseWal(pPager)==0 || (!isMainJrnl && isSavepnt) );
 
+  /* Either the state is greater than PAGER_WRITER_CACHEMOD (a transaction 
+  ** or savepoint rollback done at the request of the caller) or this is
+  ** a hot-journal rollback. If it is a hot-journal rollback, the pager
+  ** is in state OPEN and holds an EXCLUSIVE lock. Hot-journal rollback
+  ** only reads from the main journal, not the sub-journal.
+  */
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD
+       || (pPager->eState==PAGER_OPEN && pPager->eLock==EXCLUSIVE_LOCK)
+  );
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD || isMainJrnl );
+
+  /* Read the page number and page data from the journal or sub-journal
+  ** file. Return an error code to the caller if an IO error occurs.
+  */
   jfd = isMainJrnl ? pPager->jfd : pPager->sjfd;
-
   rc = read32bits(jfd, *pOffset, &pgno);
   if( rc!=SQLITE_OK ) return rc;
-  rc = sqlite3OsRead(jfd, aData, pPager->pageSize, (*pOffset)+4);
+  rc = sqlite3OsRead(jfd, (u8*)aData, pPager->pageSize, (*pOffset)+4);
   if( rc!=SQLITE_OK ) return rc;
   *pOffset += pPager->pageSize + 4 + isMainJrnl*4;
 
@@ -31956,6 +39102,7 @@ static int pager_playback_one_page(
   ** detect this invalid data (with high probability) and ignore it.
   */
   if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
+    assert( !isSavepnt );
     return SQLITE_DONE;
   }
   if( pgno>(Pgno)pPager->dbSize || sqlite3BitvecTest(pDone, pgno) ){
@@ -31964,17 +39111,26 @@ static int pager_playback_one_page(
   if( isMainJrnl ){
     rc = read32bits(jfd, (*pOffset)-4, &cksum);
     if( rc ) return rc;
-    if( !isSavepnt && pager_cksum(pPager, aData)!=cksum ){
+    if( !isSavepnt && pager_cksum(pPager, (u8*)aData)!=cksum ){
       return SQLITE_DONE;
     }
   }
-  if( pDone && (rc = sqlite3BitvecSet(pDone, pgno)) ){
+
+  /* If this page has already been played by before during the current
+  ** rollback, then don't bother to play it back again.
+  */
+  if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
     return rc;
   }
 
-  assert( pPager->state==PAGER_RESERVED || pPager->state>=PAGER_EXCLUSIVE );
+  /* When playing back page 1, restore the nReserve setting
+  */
+  if( pgno==1 && pPager->nReserve!=((u8*)aData)[20] ){
+    pPager->nReserve = ((u8*)aData)[20];
+    pagerReportSize(pPager);
+  }
 
-  /* If the pager is in RESERVED state, then there must be a copy of this
+  /* If the pager is in CACHEMOD state, then there must be a copy of this
   ** page in the pager cache. In this case just update the pager cache,
   ** not the database file. The page is left marked dirty in this case.
   **
@@ -31985,8 +39141,11 @@ static int pager_playback_one_page(
   ** either. So the condition described in the above paragraph is not
   ** assert()able.
   **
-  ** If in EXCLUSIVE state, then we update the pager cache if it exists
-  ** and the main file. The page is then marked not dirty.
+  ** If in WRITER_DBMOD, WRITER_FINISHED or OPEN state, then we update the
+  ** pager cache if it exists and the main file. The page is then marked 
+  ** not dirty. Since this code is only executed in PAGER_OPEN state for
+  ** a hot-journal rollback, it is guaranteed that the page-cache is empty
+  ** if the pager is in OPEN state.
   **
   ** Ticket #1171:  The statement journal might contain page content that is
   ** different from the page content at the start of the transaction.
@@ -32006,20 +39165,38 @@ static int pager_playback_one_page(
   ** is possible to fail a statement on a database that does not yet exist.
   ** Do not attempt to write if database file has never been opened.
   */
-  pPg = pager_lookup(pPager, pgno);
+  if( pagerUseWal(pPager) ){
+    pPg = 0;
+  }else{
+    pPg = pager_lookup(pPager, pgno);
+  }
+  assert( pPg || !MEMDB );
+  assert( pPager->eState!=PAGER_OPEN || pPg==0 );
   PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
-               PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, aData),
-               (isMainJrnl?"main-journal":"sub-journal")
+           PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, (u8*)aData),
+           (isMainJrnl?"main-journal":"sub-journal")
   ));
-  if( (pPager->state>=PAGER_EXCLUSIVE)
-   && (pPg==0 || 0==(pPg->flags&PGHDR_NEED_SYNC))
-   && (pPager->fd->pMethods)
+  if( isMainJrnl ){
+    isSynced = pPager->noSync || (*pOffset <= pPager->journalHdr);
+  }else{
+    isSynced = (pPg==0 || 0==(pPg->flags & PGHDR_NEED_SYNC));
+  }
+  if( isOpen(pPager->fd)
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+   && isSynced
   ){
     i64 ofst = (pgno-1)*(i64)pPager->pageSize;
-    rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize, ofst);
+    testcase( !isSavepnt && pPg!=0 && (pPg->flags&PGHDR_NEED_SYNC)!=0 );
+    assert( !pagerUseWal(pPager) );
+    rc = sqlite3OsWrite(pPager->fd, (u8*)aData, pPager->pageSize, ofst);
     if( pgno>pPager->dbFileSize ){
       pPager->dbFileSize = pgno;
     }
+    if( pPager->pBackup ){
+      CODEC1(pPager, aData, pgno, 3, rc=SQLITE_NOMEM);
+      sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)aData);
+      CODEC2(pPager, aData, pgno, 7, rc=SQLITE_NOMEM, aData);
+    }
   }else if( !isMainJrnl && pPg==0 ){
     /* If this is a rollback of a savepoint and data was not written to
     ** the database and the page is not in-memory, there is a potential
@@ -32038,9 +39215,12 @@ static int pager_playback_one_page(
     ** requiring a journal-sync before it is written.
     */
     assert( isSavepnt );
-    if( (rc = sqlite3PagerAcquire(pPager, pgno, &pPg, 1)) ){
-      return rc;
-    }
+    assert( pPager->doNotSpill==0 );
+    pPager->doNotSpill++;
+    rc = sqlite3PagerAcquire(pPager, pgno, &pPg, 1);
+    assert( pPager->doNotSpill==1 );
+    pPager->doNotSpill--;
+    if( rc!=SQLITE_OK ) return rc;
     pPg->flags &= ~PGHDR_NEED_READ;
     sqlite3PcacheMakeDirty(pPg);
   }
@@ -32053,15 +39233,14 @@ static int pager_playback_one_page(
     */
     void *pData;
     pData = pPg->pData;
-    memcpy(pData, aData, pPager->pageSize);
-    if( pPager->xReiniter ){
-      pPager->xReiniter(pPg);
-    }
-    if( isMainJrnl && (!isSavepnt || pPager->journalOff<=pPager->journalHdr) ){
+    memcpy(pData, (u8*)aData, pPager->pageSize);
+    pPager->xReiniter(pPg);
+    if( isMainJrnl && (!isSavepnt || *pOffset<=pPager->journalHdr) ){
       /* If the contents of this page were just restored from the main 
       ** journal file, then its content must be as they were when the 
       ** transaction was first opened. In this case we can mark the page
-      ** as clean, since there will be no need to write it out to the.
+      ** as clean, since there will be no need to write it out to the
+      ** database.
       **
       ** There is one exception to this rule. If the page is being rolled
       ** back as part of a savepoint (or statement) rollback from an 
@@ -32076,11 +39255,11 @@ static int pager_playback_one_page(
       ** segment is synced. If a crash occurs during or following this,
       ** database corruption may ensue.
       */
+      assert( !pagerUseWal(pPager) );
       sqlite3PcacheMakeClean(pPg);
     }
-#ifdef SQLITE_CHECK_PAGES
-    pPg->pageHash = pager_pagehash(pPg);
-#endif
+    pager_set_pagehash(pPg);
+
     /* If this was page 1, then restore the value of Pager.dbFileVers.
     ** Do this before any decoding. */
     if( pgno==1 ){
@@ -32088,52 +39267,12 @@ static int pager_playback_one_page(
     }
 
     /* Decode the page just read from disk */
-    CODEC1(pPager, pData, pPg->pgno, 3);
+    CODEC1(pPager, pData, pPg->pgno, 3, rc=SQLITE_NOMEM);
     sqlite3PcacheRelease(pPg);
   }
   return rc;
 }
 
-#if !defined(NDEBUG) || defined(SQLITE_COVERAGE_TEST)
-/*
-** This routine looks ahead into the main journal file and determines
-** whether or not the next record (the record that begins at file
-** offset pPager->journalOff) is a well-formed page record consisting
-** of a valid page number, pPage->pageSize bytes of content, followed
-** by a valid checksum.
-**
-** The pager never needs to know this in order to do its job.   This
-** routine is only used from with assert() and testcase() macros.
-*/
-static int pagerNextJournalPageIsValid(Pager *pPager){
-  Pgno pgno;           /* The page number of the page */
-  u32 cksum;           /* The page checksum */
-  int rc;              /* Return code from read operations */
-  sqlite3_file *fd;    /* The file descriptor from which we are reading */
-  u8 *aData;           /* Content of the page */
-
-  /* Read the page number header */
-  fd = pPager->jfd;
-  rc = read32bits(fd, pPager->journalOff, &pgno);
-  if( rc!=SQLITE_OK ){ return 0; }                                  /*NO_TEST*/
-  if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){ return 0; }         /*NO_TEST*/
-  if( pgno>(Pgno)pPager->dbSize ){ return 0; }                      /*NO_TEST*/
-
-  /* Read the checksum */
-  rc = read32bits(fd, pPager->journalOff+pPager->pageSize+4, &cksum);
-  if( rc!=SQLITE_OK ){ return 0; }                                  /*NO_TEST*/
-
-  /* Read the data and verify the checksum */
-  aData = (u8*)pPager->pTmpSpace;
-  rc = sqlite3OsRead(fd, aData, pPager->pageSize, pPager->journalOff+4);
-  if( rc!=SQLITE_OK ){ return 0; }                                  /*NO_TEST*/
-  if( pager_cksum(pPager, aData)!=cksum ){ return 0; }              /*NO_TEST*/
-
-  /* Reach this point only if the page is valid */
-  return 1;
-}
-#endif /* !defined(NDEBUG) || defined(SQLITE_COVERAGE_TEST) */
-
 /*
 ** Parameter zMaster is the name of a master journal file. A single journal
 ** file that referred to the master journal file has just been rolled back.
@@ -32143,129 +39282,173 @@ static int pagerNextJournalPageIsValid(Pager *pPager){
 ** Argument zMaster may point to Pager.pTmpSpace. So that buffer is not 
 ** available for use within this function.
 **
+** When a master journal file is created, it is populated with the names 
+** of all of its child journals, one after another, formatted as utf-8 
+** encoded text. The end of each child journal file is marked with a 
+** nul-terminator byte (0x00). i.e. the entire contents of a master journal
+** file for a transaction involving two databases might be:
 **
-** The master journal file contains the names of all child journals.
-** To tell if a master journal can be deleted, check to each of the
-** children.  If all children are either missing or do not refer to
-** a different master journal, then this master journal can be deleted.
+**   "/home/bill/a.db-journal\x00/home/bill/b.db-journal\x00"
+**
+** A master journal file may only be deleted once all of its child 
+** journals have been rolled back.
+**
+** This function reads the contents of the master-journal file into 
+** memory and loops through each of the child journal names. For
+** each child journal, it checks if:
+**
+**   * if the child journal exists, and if so
+**   * if the child journal contains a reference to master journal 
+**     file zMaster
+**
+** If a child journal can be found that matches both of the criteria
+** above, this function returns without doing anything. Otherwise, if
+** no such child journal can be found, file zMaster is deleted from
+** the file-system using sqlite3OsDelete().
+**
+** If an IO error within this function, an error code is returned. This
+** function allocates memory by calling sqlite3Malloc(). If an allocation
+** fails, SQLITE_NOMEM is returned. Otherwise, if no IO or malloc errors 
+** occur, SQLITE_OK is returned.
+**
+** TODO: This function allocates a single block of memory to load
+** the entire contents of the master journal file. This could be
+** a couple of kilobytes or so - potentially larger than the page 
+** size.
 */
 static int pager_delmaster(Pager *pPager, const char *zMaster){
   sqlite3_vfs *pVfs = pPager->pVfs;
-  int rc;
-  int master_open = 0;
-  sqlite3_file *pMaster;
-  sqlite3_file *pJournal;
+  int rc;                   /* Return code */
+  sqlite3_file *pMaster;    /* Malloc'd master-journal file descriptor */
+  sqlite3_file *pJournal;   /* Malloc'd child-journal file descriptor */
   char *zMasterJournal = 0; /* Contents of master journal file */
   i64 nMasterJournal;       /* Size of master journal file */
+  char *zJournal;           /* Pointer to one journal within MJ file */
+  char *zMasterPtr;         /* Space to hold MJ filename from a journal file */
+  int nMasterPtr;           /* Amount of space allocated to zMasterPtr[] */
 
-  /* Open the master journal file exclusively in case some other process
-  ** is running this routine also. Not that it makes too much difference.
+  /* Allocate space for both the pJournal and pMaster file descriptors.
+  ** If successful, open the master journal file for reading.
   */
-  pMaster = (sqlite3_file *)sqlite3Malloc(pVfs->szOsFile * 2);
+  pMaster = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile * 2);
   pJournal = (sqlite3_file *)(((u8 *)pMaster) + pVfs->szOsFile);
   if( !pMaster ){
     rc = SQLITE_NOMEM;
   }else{
-    int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MASTER_JOURNAL);
+    const int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MASTER_JOURNAL);
     rc = sqlite3OsOpen(pVfs, zMaster, pMaster, flags, 0);
   }
   if( rc!=SQLITE_OK ) goto delmaster_out;
-  master_open = 1;
 
+  /* Load the entire master journal file into space obtained from
+  ** sqlite3_malloc() and pointed to by zMasterJournal.   Also obtain
+  ** sufficient space (in zMasterPtr) to hold the names of master
+  ** journal files extracted from regular rollback-journals.
+  */
   rc = sqlite3OsFileSize(pMaster, &nMasterJournal);
   if( rc!=SQLITE_OK ) goto delmaster_out;
+  nMasterPtr = pVfs->mxPathname+1;
+  zMasterJournal = sqlite3Malloc((int)nMasterJournal + nMasterPtr + 1);
+  if( !zMasterJournal ){
+    rc = SQLITE_NOMEM;
+    goto delmaster_out;
+  }
+  zMasterPtr = &zMasterJournal[nMasterJournal+1];
+  rc = sqlite3OsRead(pMaster, zMasterJournal, (int)nMasterJournal, 0);
+  if( rc!=SQLITE_OK ) goto delmaster_out;
+  zMasterJournal[nMasterJournal] = 0;
 
-  if( nMasterJournal>0 ){
-    char *zJournal;
-    char *zMasterPtr = 0;
-    int nMasterPtr = pPager->pVfs->mxPathname+1;
-
-    /* Load the entire master journal file into space obtained from
-    ** sqlite3_malloc() and pointed to by zMasterJournal. 
-    */
-    zMasterJournal = (char *)sqlite3Malloc((int)nMasterJournal + nMasterPtr);
-    if( !zMasterJournal ){
-      rc = SQLITE_NOMEM;
+  zJournal = zMasterJournal;
+  while( (zJournal-zMasterJournal)<nMasterJournal ){
+    int exists;
+    rc = sqlite3OsAccess(pVfs, zJournal, SQLITE_ACCESS_EXISTS, &exists);
+    if( rc!=SQLITE_OK ){
       goto delmaster_out;
     }
-    zMasterPtr = &zMasterJournal[nMasterJournal];
-    rc = sqlite3OsRead(pMaster, zMasterJournal, (int)nMasterJournal, 0);
-    if( rc!=SQLITE_OK ) goto delmaster_out;
-
-    zJournal = zMasterJournal;
-    while( (zJournal-zMasterJournal)<nMasterJournal ){
-      int exists;
-      rc = sqlite3OsAccess(pVfs, zJournal, SQLITE_ACCESS_EXISTS, &exists);
+    if( exists ){
+      /* One of the journals pointed to by the master journal exists.
+      ** Open it and check if it points at the master journal. If
+      ** so, return without deleting the master journal file.
+      */
+      int c;
+      int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL);
+      rc = sqlite3OsOpen(pVfs, zJournal, pJournal, flags, 0);
       if( rc!=SQLITE_OK ){
         goto delmaster_out;
       }
-      if( exists ){
-        /* One of the journals pointed to by the master journal exists.
-        ** Open it and check if it points at the master journal. If
-        ** so, return without deleting the master journal file.
-        */
-        int c;
-        int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL);
-        rc = sqlite3OsOpen(pVfs, zJournal, pJournal, flags, 0);
-        if( rc!=SQLITE_OK ){
-          goto delmaster_out;
-        }
 
-        rc = readMasterJournal(pJournal, zMasterPtr, nMasterPtr);
-        sqlite3OsClose(pJournal);
-        if( rc!=SQLITE_OK ){
-          goto delmaster_out;
-        }
-
-        c = zMasterPtr[0]!=0 && strcmp(zMasterPtr, zMaster)==0;
-        if( c ){
-          /* We have a match. Do not delete the master journal file. */
-          goto delmaster_out;
-        }
+      rc = readMasterJournal(pJournal, zMasterPtr, nMasterPtr);
+      sqlite3OsClose(pJournal);
+      if( rc!=SQLITE_OK ){
+        goto delmaster_out;
+      }
+
+      c = zMasterPtr[0]!=0 && strcmp(zMasterPtr, zMaster)==0;
+      if( c ){
+        /* We have a match. Do not delete the master journal file. */
+        goto delmaster_out;
       }
-      zJournal += (sqlite3Strlen30(zJournal)+1);
     }
+    zJournal += (sqlite3Strlen30(zJournal)+1);
   }
-  
+ 
+  sqlite3OsClose(pMaster);
   rc = sqlite3OsDelete(pVfs, zMaster, 0);
 
 delmaster_out:
-  if( zMasterJournal ){
-    sqlite3_free(zMasterJournal);
-  }  
-  if( master_open ){
+  sqlite3_free(zMasterJournal);
+  if( pMaster ){
     sqlite3OsClose(pMaster);
+    assert( !isOpen(pJournal) );
+    sqlite3_free(pMaster);
   }
-  sqlite3_free(pMaster);
   return rc;
 }
 
 
 /*
-** If the main database file is open and an exclusive lock is held, 
-** truncate the main file of the given pager to the specified number 
-** of pages.
+** This function is used to change the actual size of the database 
+** file in the file-system. This only happens when committing a transaction,
+** or rolling back a transaction (including rolling back a hot-journal).
 **
-** It might might be the case that the file on disk is smaller than nPage.
-** This can happen, for example, if we are in the middle of a transaction
-** which has extended the file size and the new pages are still all held
-** in cache, then an INSERT or UPDATE does a statement rollback.  Some
-** operating system implementations can get confused if you try to
-** truncate a file to some size that is larger than it currently is,
-** so detect this case and write a single zero byte to the end of the new
-** file instead.
+** If the main database file is not open, or the pager is not in either
+** DBMOD or OPEN state, this function is a no-op. Otherwise, the size 
+** of the file is changed to nPage pages (nPage*pPager->pageSize bytes). 
+** If the file on disk is currently larger than nPage pages, then use the VFS
+** xTruncate() method to truncate it.
+**
+** Or, it might might be the case that the file on disk is smaller than 
+** nPage pages. Some operating system implementations can get confused if 
+** you try to truncate a file to some size that is larger than it 
+** currently is, so detect this case and write a single zero byte to 
+** the end of the new file instead.
+**
+** If successful, return SQLITE_OK. If an IO error occurs while modifying
+** the database file, return the error code to the caller.
 */
 static int pager_truncate(Pager *pPager, Pgno nPage){
   int rc = SQLITE_OK;
-  if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( pPager->eState!=PAGER_READER );
+  
+  if( isOpen(pPager->fd) 
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN) 
+  ){
     i64 currentSize, newSize;
+    int szPage = pPager->pageSize;
+    assert( pPager->eLock==EXCLUSIVE_LOCK );
+    /* TODO: Is it safe to use Pager.dbFileSize here? */
     rc = sqlite3OsFileSize(pPager->fd, &currentSize);
-    newSize = pPager->pageSize*(i64)nPage;
+    newSize = szPage*(i64)nPage;
     if( rc==SQLITE_OK && currentSize!=newSize ){
       if( currentSize>newSize ){
         rc = sqlite3OsTruncate(pPager->fd, newSize);
-      }else{
-        rc = sqlite3OsWrite(pPager->fd, "", 1, newSize-1);
+      }else if( (currentSize+szPage)<=newSize ){
+        char *pTmp = pPager->pTmpSpace;
+        memset(pTmp, 0, szPage);
+        testcase( (newSize-szPage) == currentSize );
+        testcase( (newSize-szPage) >  currentSize );
+        rc = sqlite3OsWrite(pPager->fd, pTmp, szPage, newSize-szPage);
       }
       if( rc==SQLITE_OK ){
         pPager->dbFileSize = nPage;
@@ -32276,25 +39459,48 @@ static int pager_truncate(Pager *pPager, Pgno nPage){
 }
 
 /*
-** Set the sectorSize for the given pager.
+** Set the value of the Pager.sectorSize variable for the given
+** pager based on the value returned by the xSectorSize method
+** of the open database file. The sector size will be used used 
+** to determine the size and alignment of journal header and 
+** master journal pointers within created journal files.
 **
-** The sector size is at least as big as the sector size reported
-** by sqlite3OsSectorSize(). The minimum sector size is 512.
+** For temporary files the effective sector size is always 512 bytes.
+**
+** Otherwise, for non-temporary files, the effective sector size is
+** the value returned by the xSectorSize() method rounded up to 32 if
+** it is less than 32, or rounded down to MAX_SECTOR_SIZE if it
+** is greater than MAX_SECTOR_SIZE.
+**
+** If the file has the SQLITE_IOCAP_POWERSAFE_OVERWRITE property, then set
+** the effective sector size to its minimum value (512).  The purpose of
+** pPager->sectorSize is to define the "blast radius" of bytes that
+** might change if a crash occurs while writing to a single byte in
+** that range.  But with POWERSAFE_OVERWRITE, the blast radius is zero
+** (that is what POWERSAFE_OVERWRITE means), so we minimize the sector
+** size.  For backwards compatibility of the rollback journal file format,
+** we cannot reduce the effective sector size below 512.
 */
 static void setSectorSize(Pager *pPager){
-  assert(pPager->fd->pMethods||pPager->tempFile);
-  if( !pPager->tempFile ){
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+
+  if( pPager->tempFile
+   || (sqlite3OsDeviceCharacteristics(pPager->fd) & 
+              SQLITE_IOCAP_POWERSAFE_OVERWRITE)!=0
+  ){
     /* Sector size doesn't matter for temporary files. Also, the file
-    ** may not have been opened yet, in whcih case the OsSectorSize()
-    ** call will segfault.
-    */
-    pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
-  }
-  if( pPager->sectorSize<512 ){
+    ** may not have been opened yet, in which case the OsSectorSize()
+    ** call will segfault. */
     pPager->sectorSize = 512;
-  }
-  if( pPager->sectorSize>MAX_SECTOR_SIZE ){
-    pPager->sectorSize = MAX_SECTOR_SIZE;
+  }else{
+    pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
+    if( pPager->sectorSize<32 ){
+      pPager->sectorSize = 512;
+    }
+    if( pPager->sectorSize>MAX_SECTOR_SIZE ){
+      assert( MAX_SECTOR_SIZE>=512 );
+      pPager->sectorSize = MAX_SECTOR_SIZE;
+    }
   }
 }
 
@@ -32314,21 +39520,15 @@ static void setSectorSize(Pager *pPager){
 **       database to during a rollback.
 **  (5)  4 byte big-endian integer which is the sector size.  The header
 **       is this many bytes in size.
-**  (6)  4 byte big-endian integer which is the page case.
-**  (7)  4 byte integer which is the number of bytes in the master journal
-**       name.  The value may be zero (indicate that there is no master
-**       journal.)
-**  (8)  N bytes of the master journal name.  The name will be nul-terminated
-**       and might be shorter than the value read from (5).  If the first byte
-**       of the name is \000 then there is no master journal.  The master
-**       journal name is stored in UTF-8.
-**  (9)  Zero or more pages instances, each as follows:
+**  (6)  4 byte big-endian integer which is the page size.
+**  (7)  zero padding out to the next sector size.
+**  (8)  Zero or more pages instances, each as follows:
 **        +  4 byte page number.
 **        +  pPager->pageSize bytes of data.
 **        +  4 byte checksum
 **
-** When we speak of the journal header, we mean the first 8 items above.
-** Each entry in the journal is an instance of the 9th item.
+** When we speak of the journal header, we mean the first 7 items above.
+** Each entry in the journal is an instance of the 8th item.
 **
 ** Call the value from the second bullet "nRec".  nRec is the number of
 ** valid page entries in the journal.  In most cases, you can compute the
@@ -32353,6 +39553,13 @@ static void setSectorSize(Pager *pPager){
 **
 ** If an I/O or malloc() error occurs, the journal-file is not deleted
 ** and an error code is returned.
+**
+** The isHot parameter indicates that we are trying to rollback a journal
+** that might be a hot journal.  Or, it could be that the journal is 
+** preserved because of JOURNALMODE_PERSIST or JOURNALMODE_TRUNCATE.
+** If the journal really is hot, reset the pager cache prior rolling
+** back any content.  If the journal is merely persistent, no reset is
+** needed.
 */
 static int pager_playback(Pager *pPager, int isHot){
   sqlite3_vfs *pVfs = pPager->pVfs;
@@ -32363,13 +39570,14 @@ static int pager_playback(Pager *pPager, int isHot){
   int rc;                  /* Result code of a subroutine */
   int res = 1;             /* Value returned by sqlite3OsAccess() */
   char *zMaster = 0;       /* Name of master journal file if any */
+  int needPagerReset;      /* True to reset page prior to first page rollback */
 
   /* Figure out how many records are in the journal.  Abort early if
   ** the journal is empty.
   */
-  assert( pPager->journalOpen );
+  assert( isOpen(pPager->jfd) );
   rc = sqlite3OsFileSize(pPager->jfd, &szJ);
-  if( rc!=SQLITE_OK || szJ==0 ){
+  if( rc!=SQLITE_OK ){
     goto end_playback;
   }
 
@@ -32377,6 +39585,12 @@ static int pager_playback(Pager *pPager, int isHot){
   ** If a master journal file name is specified, but the file is not
   ** present on disk, then the journal is not hot and does not need to be
   ** played back.
+  **
+  ** TODO: Technically the following is an error because it assumes that
+  ** buffer Pager.pTmpSpace is (mxPathname+1) bytes or larger. i.e. that
+  ** (pPager->pageSize >= pPager->pVfs->mxPathname+1). Using os_unix.c,
+  **  mxPathname is 512, which is the same as the minimum allowable value
+  ** for pageSize.
   */
   zMaster = pPager->pTmpSpace;
   rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
@@ -32388,17 +39602,19 @@ static int pager_playback(Pager *pPager, int isHot){
     goto end_playback;
   }
   pPager->journalOff = 0;
+  needPagerReset = isHot;
 
-  /* This loop terminates either when the readJournalHdr() call returns
-  ** SQLITE_DONE or an IO error occurs. */
+  /* This loop terminates either when a readJournalHdr() or 
+  ** pager_playback_one_page() call returns SQLITE_DONE or an IO error 
+  ** occurs. 
+  */
   while( 1 ){
-
     /* Read the next journal header from the journal file.  If there are
     ** not enough bytes left in the journal file for a complete header, or
-    ** it is corrupted, then a process must of failed while writing it.
+    ** it is corrupted, then a process must have failed while writing it.
     ** This indicates nothing more needs to be rolled back.
     */
-    rc = readJournalHdr(pPager, szJ, &nRec, &mxPg);
+    rc = readJournalHdr(pPager, isHot, szJ, &nRec, &mxPg);
     if( rc!=SQLITE_OK ){ 
       if( rc==SQLITE_DONE ){
         rc = SQLITE_OK;
@@ -32430,11 +39646,6 @@ static int pager_playback(Pager *pPager, int isHot){
     ** pages that need to be rolled back and that the number of pages 
     ** should be computed based on the journal file size.
     */
-    testcase( nRec==0 && !isHot
-         && pPager->journalHdr+JOURNAL_HDR_SZ(pPager)!=pPager->journalOff
-         && ((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager))>0
-         && pagerNextJournalPageIsValid(pPager)
-    );
     if( nRec==0 && !isHot &&
         pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff ){
       nRec = (int)((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager));
@@ -32451,21 +39662,33 @@ static int pager_playback(Pager *pPager, int isHot){
       pPager->dbSize = mxPg;
     }
 
-    /* Copy original pages out of the journal and back into the database file.
+    /* Copy original pages out of the journal and back into the 
+    ** database file and/or page cache.
     */
     for(u=0; u<nRec; u++){
-      rc = pager_playback_one_page(pPager, 1, &pPager->journalOff, 0, 0);
+      if( needPagerReset ){
+        pager_reset(pPager);
+        needPagerReset = 0;
+      }
+      rc = pager_playback_one_page(pPager,&pPager->journalOff,0,1,0);
       if( rc!=SQLITE_OK ){
         if( rc==SQLITE_DONE ){
-          rc = SQLITE_OK;
           pPager->journalOff = szJ;
           break;
+        }else if( rc==SQLITE_IOERR_SHORT_READ ){
+          /* If the journal has been truncated, simply stop reading and
+          ** processing the journal. This might happen if the journal was
+          ** not completely written and synced prior to a crash.  In that
+          ** case, the database should have never been written in the
+          ** first place so it is OK to simply abandon the rollback. */
+          rc = SQLITE_OK;
+          goto end_playback;
         }else{
-          /* If we are unable to rollback, then the database is probably
-          ** going to end up being corrupt.  It is corrupt to us, anyhow.
-          ** Perhaps the next process to come along can fix it....
+          /* If we are unable to rollback, quit and return the error
+          ** code.  This will cause the pager to enter the error state
+          ** so that no further harm will be done.  Perhaps the next
+          ** process to come along will be able to rollback the database.
           */
-          rc = SQLITE_CORRUPT_BKPT;
           goto end_playback;
         }
       }
@@ -32480,23 +39703,43 @@ end_playback:
   ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
   ** assertion that the transaction counter was modified.
   */
-  assert(
-    pPager->fd->pMethods==0 ||
-    sqlite3OsFileControl(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0)>=SQLITE_OK
-  );
+#ifdef SQLITE_DEBUG
+  if( pPager->fd->pMethods ){
+    sqlite3OsFileControlHint(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0);
+  }
+#endif
+
+  /* If this playback is happening automatically as a result of an IO or 
+  ** malloc error that occurred after the change-counter was updated but 
+  ** before the transaction was committed, then the change-counter 
+  ** modification may just have been reverted. If this happens in exclusive 
+  ** mode, then subsequent transactions performed by the connection will not
+  ** update the change-counter at all. This may lead to cache inconsistency
+  ** problems for other processes at some point in the future. So, just
+  ** in case this has happened, clear the changeCountDone flag now.
+  */
+  pPager->changeCountDone = pPager->tempFile;
 
   if( rc==SQLITE_OK ){
     zMaster = pPager->pTmpSpace;
     rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
+    testcase( rc!=SQLITE_OK );
+  }
+  if( rc==SQLITE_OK
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+  ){
+    rc = sqlite3PagerSync(pPager);
   }
   if( rc==SQLITE_OK ){
     rc = pager_end_transaction(pPager, zMaster[0]!='\0');
+    testcase( rc!=SQLITE_OK );
   }
   if( rc==SQLITE_OK && zMaster[0] && res ){
     /* If there was a master journal and this routine will return success,
     ** see if it is possible to delete the master journal.
     */
     rc = pager_delmaster(pPager, zMaster);
+    testcase( rc!=SQLITE_OK );
   }
 
   /* The Pager.sectorSize variable may have been updated while rolling
@@ -32507,20 +39750,420 @@ end_playback:
   return rc;
 }
 
+
 /*
-** Playback savepoint pSavepoint.  Or, if pSavepoint==NULL, then playback
-** the entire master journal file.
+** Read the content for page pPg out of the database file and into 
+** pPg->pData. A shared lock or greater must be held on the database
+** file before this function is called.
 **
-** The case pSavepoint==NULL occurs when a ROLLBACK TO command is invoked
-** on a SAVEPOINT that is a transaction savepoint.
+** If page 1 is read, then the value of Pager.dbFileVers[] is set to
+** the value read from the database file.
+**
+** If an IO error occurs, then the IO error is returned to the caller.
+** Otherwise, SQLITE_OK is returned.
+*/
+static int readDbPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager; /* Pager object associated with page pPg */
+  Pgno pgno = pPg->pgno;       /* Page number to read */
+  int rc = SQLITE_OK;          /* Return code */
+  int isInWal = 0;             /* True if page is in log file */
+  int pgsz = pPager->pageSize; /* Number of bytes to read */
+
+  assert( pPager->eState>=PAGER_READER && !MEMDB );
+  assert( isOpen(pPager->fd) );
+
+  if( NEVER(!isOpen(pPager->fd)) ){
+    assert( pPager->tempFile );
+    memset(pPg->pData, 0, pPager->pageSize);
+    return SQLITE_OK;
+  }
+
+  if( pagerUseWal(pPager) ){
+    /* Try to pull the page from the write-ahead log. */
+    rc = sqlite3WalRead(pPager->pWal, pgno, &isInWal, pgsz, pPg->pData);
+  }
+  if( rc==SQLITE_OK && !isInWal ){
+    i64 iOffset = (pgno-1)*(i64)pPager->pageSize;
+    rc = sqlite3OsRead(pPager->fd, pPg->pData, pgsz, iOffset);
+    if( rc==SQLITE_IOERR_SHORT_READ ){
+      rc = SQLITE_OK;
+    }
+  }
+
+  if( pgno==1 ){
+    if( rc ){
+      /* If the read is unsuccessful, set the dbFileVers[] to something
+      ** that will never be a valid file version.  dbFileVers[] is a copy
+      ** of bytes 24..39 of the database.  Bytes 28..31 should always be
+      ** zero or the size of the database in page. Bytes 32..35 and 35..39
+      ** should be page numbers which are never 0xffffffff.  So filling
+      ** pPager->dbFileVers[] with all 0xff bytes should suffice.
+      **
+      ** For an encrypted database, the situation is more complex:  bytes
+      ** 24..39 of the database are white noise.  But the probability of
+      ** white noising equaling 16 bytes of 0xff is vanishingly small so
+      ** we should still be ok.
+      */
+      memset(pPager->dbFileVers, 0xff, sizeof(pPager->dbFileVers));
+    }else{
+      u8 *dbFileVers = &((u8*)pPg->pData)[24];
+      memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
+    }
+  }
+  CODEC1(pPager, pPg->pData, pgno, 3, rc = SQLITE_NOMEM);
+
+  PAGER_INCR(sqlite3_pager_readdb_count);
+  PAGER_INCR(pPager->nRead);
+  IOTRACE(("PGIN %p %d\n", pPager, pgno));
+  PAGERTRACE(("FETCH %d page %d hash(%08x)\n",
+               PAGERID(pPager), pgno, pager_pagehash(pPg)));
+
+  return rc;
+}
+
+/*
+** Update the value of the change-counter at offsets 24 and 92 in
+** the header and the sqlite version number at offset 96.
+**
+** This is an unconditional update.  See also the pager_incr_changecounter()
+** routine which only updates the change-counter if the update is actually
+** needed, as determined by the pPager->changeCountDone state variable.
+*/
+static void pager_write_changecounter(PgHdr *pPg){
+  u32 change_counter;
+
+  /* Increment the value just read and write it back to byte 24. */
+  change_counter = sqlite3Get4byte((u8*)pPg->pPager->dbFileVers)+1;
+  put32bits(((char*)pPg->pData)+24, change_counter);
+
+  /* Also store the SQLite version number in bytes 96..99 and in
+  ** bytes 92..95 store the change counter for which the version number
+  ** is valid. */
+  put32bits(((char*)pPg->pData)+92, change_counter);
+  put32bits(((char*)pPg->pData)+96, SQLITE_VERSION_NUMBER);
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** This function is invoked once for each page that has already been 
+** written into the log file when a WAL transaction is rolled back.
+** Parameter iPg is the page number of said page. The pCtx argument 
+** is actually a pointer to the Pager structure.
+**
+** If page iPg is present in the cache, and has no outstanding references,
+** it is discarded. Otherwise, if there are one or more outstanding
+** references, the page content is reloaded from the database. If the
+** attempt to reload content from the database is required and fails, 
+** return an SQLite error code. Otherwise, SQLITE_OK.
+*/
+static int pagerUndoCallback(void *pCtx, Pgno iPg){
+  int rc = SQLITE_OK;
+  Pager *pPager = (Pager *)pCtx;
+  PgHdr *pPg;
+
+  pPg = sqlite3PagerLookup(pPager, iPg);
+  if( pPg ){
+    if( sqlite3PcachePageRefcount(pPg)==1 ){
+      sqlite3PcacheDrop(pPg);
+    }else{
+      rc = readDbPage(pPg);
+      if( rc==SQLITE_OK ){
+        pPager->xReiniter(pPg);
+      }
+      sqlite3PagerUnref(pPg);
+    }
+  }
+
+  /* Normally, if a transaction is rolled back, any backup processes are
+  ** updated as data is copied out of the rollback journal and into the
+  ** database. This is not generally possible with a WAL database, as
+  ** rollback involves simply truncating the log file. Therefore, if one
+  ** or more frames have already been written to the log (and therefore 
+  ** also copied into the backup databases) as part of this transaction,
+  ** the backups must be restarted.
+  */
+  sqlite3BackupRestart(pPager->pBackup);
+
+  return rc;
+}
+
+/*
+** This function is called to rollback a transaction on a WAL database.
+*/
+static int pagerRollbackWal(Pager *pPager){
+  int rc;                         /* Return Code */
+  PgHdr *pList;                   /* List of dirty pages to revert */
+
+  /* For all pages in the cache that are currently dirty or have already
+  ** been written (but not committed) to the log file, do one of the 
+  ** following:
+  **
+  **   + Discard the cached page (if refcount==0), or
+  **   + Reload page content from the database (if refcount>0).
+  */
+  pPager->dbSize = pPager->dbOrigSize;
+  rc = sqlite3WalUndo(pPager->pWal, pagerUndoCallback, (void *)pPager);
+  pList = sqlite3PcacheDirtyList(pPager->pPCache);
+  while( pList && rc==SQLITE_OK ){
+    PgHdr *pNext = pList->pDirty;
+    rc = pagerUndoCallback((void *)pPager, pList->pgno);
+    pList = pNext;
+  }
+
+  return rc;
+}
+
+/*
+** This function is a wrapper around sqlite3WalFrames(). As well as logging
+** the contents of the list of pages headed by pList (connected by pDirty),
+** this function notifies any active backup processes that the pages have
+** changed. 
+**
+** The list of pages passed into this routine is always sorted by page number.
+** Hence, if page 1 appears anywhere on the list, it will be the first page.
+*/ 
+static int pagerWalFrames(
+  Pager *pPager,                  /* Pager object */
+  PgHdr *pList,                   /* List of frames to log */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit                    /* True if this is a commit */
+){
+  int rc;                         /* Return code */
+  int nList;                      /* Number of pages in pList */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_CHECK_PAGES)
+  PgHdr *p;                       /* For looping over pages */
+#endif
+
+  assert( pPager->pWal );
+  assert( pList );
+#ifdef SQLITE_DEBUG
+  /* Verify that the page list is in accending order */
+  for(p=pList; p && p->pDirty; p=p->pDirty){
+    assert( p->pgno < p->pDirty->pgno );
+  }
+#endif
+
+  assert( pList->pDirty==0 || isCommit );
+  if( isCommit ){
+    /* If a WAL transaction is being committed, there is no point in writing
+    ** any pages with page numbers greater than nTruncate into the WAL file.
+    ** They will never be read by any client. So remove them from the pDirty
+    ** list here. */
+    PgHdr *p;
+    PgHdr **ppNext = &pList;
+    nList = 0;
+    for(p=pList; (*ppNext = p)!=0; p=p->pDirty){
+      if( p->pgno<=nTruncate ){
+        ppNext = &p->pDirty;
+        nList++;
+      }
+    }
+    assert( pList );
+  }else{
+    nList = 1;
+  }
+  pPager->aStat[PAGER_STAT_WRITE] += nList;
+
+  if( pList->pgno==1 ) pager_write_changecounter(pList);
+  rc = sqlite3WalFrames(pPager->pWal, 
+      pPager->pageSize, pList, nTruncate, isCommit, pPager->walSyncFlags
+  );
+  if( rc==SQLITE_OK && pPager->pBackup ){
+    PgHdr *p;
+    for(p=pList; p; p=p->pDirty){
+      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
+    }
+  }
+
+#ifdef SQLITE_CHECK_PAGES
+  pList = sqlite3PcacheDirtyList(pPager->pPCache);
+  for(p=pList; p; p=p->pDirty){
+    pager_set_pagehash(p);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** Begin a read transaction on the WAL.
+**
+** This routine used to be called "pagerOpenSnapshot()" because it essentially
+** makes a snapshot of the database at the current point in time and preserves
+** that snapshot for use by the reader in spite of concurrently changes by
+** other writers or checkpointers.
+*/
+static int pagerBeginReadTransaction(Pager *pPager){
+  int rc;                         /* Return code */
+  int changed = 0;                /* True if cache must be reset */
+
+  assert( pagerUseWal(pPager) );
+  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
+
+  /* sqlite3WalEndReadTransaction() was not called for the previous
+  ** transaction in locking_mode=EXCLUSIVE.  So call it now.  If we
+  ** are in locking_mode=NORMAL and EndRead() was previously called,
+  ** the duplicate call is harmless.
+  */
+  sqlite3WalEndReadTransaction(pPager->pWal);
+
+  rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
+  if( rc!=SQLITE_OK || changed ){
+    pager_reset(pPager);
+  }
+
+  return rc;
+}
+#endif
+
+/*
+** This function is called as part of the transition from PAGER_OPEN
+** to PAGER_READER state to determine the size of the database file
+** in pages (assuming the page size currently stored in Pager.pageSize).
+**
+** If no error occurs, SQLITE_OK is returned and the size of the database
+** in pages is stored in *pnPage. Otherwise, an error code (perhaps
+** SQLITE_IOERR_FSTAT) is returned and *pnPage is left unmodified.
+*/
+static int pagerPagecount(Pager *pPager, Pgno *pnPage){
+  Pgno nPage;                     /* Value to return via *pnPage */
+
+  /* Query the WAL sub-system for the database size. The WalDbsize()
+  ** function returns zero if the WAL is not open (i.e. Pager.pWal==0), or
+  ** if the database size is not available. The database size is not
+  ** available from the WAL sub-system if the log file is empty or
+  ** contains no valid committed transactions.
+  */
+  assert( pPager->eState==PAGER_OPEN );
+  assert( pPager->eLock>=SHARED_LOCK );
+  nPage = sqlite3WalDbsize(pPager->pWal);
+
+  /* If the database size was not available from the WAL sub-system,
+  ** determine it based on the size of the database file. If the size
+  ** of the database file is not an integer multiple of the page-size,
+  ** round down to the nearest page. Except, any file larger than 0
+  ** bytes in size is considered to contain at least one page.
+  */
+  if( nPage==0 ){
+    i64 n = 0;                    /* Size of db file in bytes */
+    assert( isOpen(pPager->fd) || pPager->tempFile );
+    if( isOpen(pPager->fd) ){
+      int rc = sqlite3OsFileSize(pPager->fd, &n);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);
+  }
+
+  /* If the current number of pages in the file is greater than the
+  ** configured maximum pager number, increase the allowed limit so
+  ** that the file can be read.
+  */
+  if( nPage>pPager->mxPgno ){
+    pPager->mxPgno = (Pgno)nPage;
+  }
+
+  *pnPage = nPage;
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Check if the *-wal file that corresponds to the database opened by pPager
+** exists if the database is not empy, or verify that the *-wal file does
+** not exist (by deleting it) if the database file is empty.
+**
+** If the database is not empty and the *-wal file exists, open the pager
+** in WAL mode.  If the database is empty or if no *-wal file exists and
+** if no error occurs, make sure Pager.journalMode is not set to
+** PAGER_JOURNALMODE_WAL.
+**
+** Return SQLITE_OK or an error code.
+**
+** The caller must hold a SHARED lock on the database file to call this
+** function. Because an EXCLUSIVE lock on the db file is required to delete 
+** a WAL on a none-empty database, this ensures there is no race condition 
+** between the xAccess() below and an xDelete() being executed by some 
+** other connection.
+*/
+static int pagerOpenWalIfPresent(Pager *pPager){
+  int rc = SQLITE_OK;
+  assert( pPager->eState==PAGER_OPEN );
+  assert( pPager->eLock>=SHARED_LOCK );
+
+  if( !pPager->tempFile ){
+    int isWal;                    /* True if WAL file exists */
+    Pgno nPage;                   /* Size of the database file */
+
+    rc = pagerPagecount(pPager, &nPage);
+    if( rc ) return rc;
+    if( nPage==0 ){
+      rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
+      isWal = 0;
+    }else{
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &isWal
+      );
+    }
+    if( rc==SQLITE_OK ){
+      if( isWal ){
+        testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
+        rc = sqlite3PagerOpenWal(pPager, 0);
+      }else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
+        pPager->journalMode = PAGER_JOURNALMODE_DELETE;
+      }
+    }
+  }
+  return rc;
+}
+#endif
+
+/*
+** Playback savepoint pSavepoint. Or, if pSavepoint==NULL, then playback
+** the entire master journal file. The case pSavepoint==NULL occurs when 
+** a ROLLBACK TO command is invoked on a SAVEPOINT that is a transaction 
+** savepoint.
+**
+** When pSavepoint is not NULL (meaning a non-transaction savepoint is 
+** being rolled back), then the rollback consists of up to three stages,
+** performed in the order specified:
+**
+**   * Pages are played back from the main journal starting at byte
+**     offset PagerSavepoint.iOffset and continuing to 
+**     PagerSavepoint.iHdrOffset, or to the end of the main journal
+**     file if PagerSavepoint.iHdrOffset is zero.
+**
+**   * If PagerSavepoint.iHdrOffset is not zero, then pages are played
+**     back starting from the journal header immediately following 
+**     PagerSavepoint.iHdrOffset to the end of the main journal file.
+**
+**   * Pages are then played back from the sub-journal file, starting
+**     with the PagerSavepoint.iSubRec and continuing to the end of
+**     the journal file.
+**
+** Throughout the rollback process, each time a page is rolled back, the
+** corresponding bit is set in a bitvec structure (variable pDone in the
+** implementation below). This is used to ensure that a page is only
+** rolled back the first time it is encountered in either journal.
+**
+** If pSavepoint is NULL, then pages are only played back from the main
+** journal file. There is no need for a bitvec in this case.
+**
+** In either case, before playback commences the Pager.dbSize variable
+** is reset to the value that it held at the start of the savepoint 
+** (or transaction). No page with a page-number greater than this value
+** is played back. If one is encountered it is simply skipped.
 */
 static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
   i64 szJ;                 /* Effective size of the main journal */
   i64 iHdrOff;             /* End of first segment of main-journal records */
-  Pgno ii;                 /* Loop counter */
   int rc = SQLITE_OK;      /* Return code */
   Bitvec *pDone = 0;       /* Bitvec to ensure pages played back only once */
 
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+
   /* Allocate a bitvec to use to store the set of pages rolled back */
   if( pSavepoint ){
     pDone = sqlite3BitvecCreate(pSavepoint->nOrig);
@@ -32529,11 +40172,15 @@ static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
     }
   }
 
-  /* Truncate the database back to the size it was before the 
-  ** savepoint being reverted was opened.
+  /* Set the database size back to the value it was before the savepoint 
+  ** being reverted was opened.
   */
   pPager->dbSize = pSavepoint ? pSavepoint->nOrig : pPager->dbOrigSize;
-  assert( pPager->state>=PAGER_SHARED );
+  pPager->changeCountDone = pPager->tempFile;
+
+  if( !pSavepoint && pagerUseWal(pPager) ){
+    return pagerRollbackWal(pPager);
+  }
 
   /* Use pPager->journalOff as the effective size of the main rollback
   ** journal.  The actual file might be larger than this in
@@ -32541,6 +40188,7 @@ static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
   ** past pPager->journalOff is off-limits to us.
   */
   szJ = pPager->journalOff;
+  assert( pagerUseWal(pPager)==0 || szJ==0 );
 
   /* Begin by rolling back records from the main journal starting at
   ** PagerSavepoint.iOffset and continuing to the next journal header.
@@ -32549,13 +40197,13 @@ static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
   ** will be skipped automatically.  Pages are added to pDone as they
   ** are played back.
   */
-  if( pSavepoint ){
+  if( pSavepoint && !pagerUseWal(pPager) ){
     iHdrOff = pSavepoint->iHdrOffset ? pSavepoint->iHdrOffset : szJ;
     pPager->journalOff = pSavepoint->iOffset;
     while( rc==SQLITE_OK && pPager->journalOff<iHdrOff ){
-      rc = pager_playback_one_page(pPager, 1, &pPager->journalOff, 1, pDone);
-      assert( rc!=SQLITE_DONE );
+      rc = pager_playback_one_page(pPager, &pPager->journalOff, pDone, 1, 1);
     }
+    assert( rc!=SQLITE_DONE );
   }else{
     pPager->journalOff = 0;
   }
@@ -32566,9 +40214,10 @@ static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
   ** continue adding pages rolled back to pDone.
   */
   while( rc==SQLITE_OK && pPager->journalOff<szJ ){
+    u32 ii;            /* Loop counter */
     u32 nJRec = 0;     /* Number of Journal Records */
     u32 dummy;
-    rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
+    rc = readJournalHdr(pPager, 0, szJ, &nJRec, &dummy);
     assert( rc!=SQLITE_DONE );
 
     /*
@@ -32576,40 +40225,41 @@ static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
     ** test is related to ticket #2565.  See the discussion in the
     ** pager_playback() function for additional information.
     */
-    assert( !(nJRec==0
-         && pPager->journalHdr+JOURNAL_HDR_SZ(pPager)!=pPager->journalOff
-         && ((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager))>0
-         && pagerNextJournalPageIsValid(pPager))
-    );
     if( nJRec==0 
      && pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff
     ){
-      nJRec = (szJ - pPager->journalOff)/JOURNAL_PG_SZ(pPager);
+      nJRec = (u32)((szJ - pPager->journalOff)/JOURNAL_PG_SZ(pPager));
     }
     for(ii=0; rc==SQLITE_OK && ii<nJRec && pPager->journalOff<szJ; ii++){
-      rc = pager_playback_one_page(pPager, 1, &pPager->journalOff, 1, pDone);
-      assert( rc!=SQLITE_DONE );
+      rc = pager_playback_one_page(pPager, &pPager->journalOff, pDone, 1, 1);
     }
+    assert( rc!=SQLITE_DONE );
   }
-  assert( rc!=SQLITE_OK || pPager->journalOff==szJ );
+  assert( rc!=SQLITE_OK || pPager->journalOff>=szJ );
 
   /* Finally,  rollback pages from the sub-journal.  Page that were
   ** previously rolled back out of the main journal (and are hence in pDone)
   ** will be skipped.  Out-of-range pages are also skipped.
   */
   if( pSavepoint ){
-    i64 offset = pSavepoint->iSubRec*(4+pPager->pageSize);
-    for(ii=pSavepoint->iSubRec; rc==SQLITE_OK&&ii<(u32)pPager->stmtNRec; ii++){
-      assert( offset == ii*(4+pPager->pageSize) );
-      rc = pager_playback_one_page(pPager, 0, &offset, 1, pDone);
-      assert( rc!=SQLITE_DONE );
+    u32 ii;            /* Loop counter */
+    i64 offset = (i64)pSavepoint->iSubRec*(4+pPager->pageSize);
+
+    if( pagerUseWal(pPager) ){
+      rc = sqlite3WalSavepointUndo(pPager->pWal, pSavepoint->aWalData);
     }
+    for(ii=pSavepoint->iSubRec; rc==SQLITE_OK && ii<pPager->nSubRec; ii++){
+      assert( offset==(i64)ii*(4+pPager->pageSize) );
+      rc = pager_playback_one_page(pPager, &offset, pDone, 0, 1);
+    }
+    assert( rc!=SQLITE_DONE );
   }
 
   sqlite3BitvecDestroy(pDone);
   if( rc==SQLITE_OK ){
     pPager->journalOff = szJ;
   }
+
   return rc;
 }
 
@@ -32620,6 +40270,13 @@ SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
   sqlite3PcacheSetCachesize(pPager->pPCache, mxPage);
 }
 
+/*
+** Free as much memory as possible from the pager.
+*/
+SQLITE_PRIVATE void sqlite3PagerShrink(Pager *pPager){
+  sqlite3PcacheShrink(pPager->pPCache);
+}
+
 /*
 ** Adjust the robustness of the database to damage due to OS crashes
 ** or power failures by changing the number of syncs()s when writing
@@ -32643,15 +40300,53 @@ SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
 **              assurance that the journal will not be corrupted to the
 **              point of causing damage to the database during rollback.
 **
+** The above is for a rollback-journal mode.  For WAL mode, OFF continues
+** to mean that no syncs ever occur.  NORMAL means that the WAL is synced
+** prior to the start of checkpoint and that the database file is synced
+** at the conclusion of the checkpoint if the entire content of the WAL
+** was written back into the database.  But no sync operations occur for
+** an ordinary commit in NORMAL mode with WAL.  FULL means that the WAL
+** file is synced following each commit operation, in addition to the
+** syncs associated with NORMAL.
+**
+** Do not confuse synchronous=FULL with SQLITE_SYNC_FULL.  The
+** SQLITE_SYNC_FULL macro means to use the MacOSX-style full-fsync
+** using fcntl(F_FULLFSYNC).  SQLITE_SYNC_NORMAL means to do an
+** ordinary fsync() call.  There is no difference between SQLITE_SYNC_FULL
+** and SQLITE_SYNC_NORMAL on platforms other than MacOSX.  But the
+** synchronous=FULL versus synchronous=NORMAL setting determines when
+** the xSync primitive is called and is relevant to all platforms.
+**
 ** Numeric values associated with these states are OFF==1, NORMAL=2,
 ** and FULL=3.
 */
 #ifndef SQLITE_OMIT_PAGER_PRAGMAS
-SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(Pager *pPager, int level, int bFullFsync){
+SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(
+  Pager *pPager,        /* The pager to set safety level for */
+  int level,            /* PRAGMA synchronous.  1=OFF, 2=NORMAL, 3=FULL */  
+  int bFullFsync,       /* PRAGMA fullfsync */
+  int bCkptFullFsync    /* PRAGMA checkpoint_fullfsync */
+){
+  assert( level>=1 && level<=3 );
   pPager->noSync =  (level==1 || pPager->tempFile) ?1:0;
   pPager->fullSync = (level==3 && !pPager->tempFile) ?1:0;
-  pPager->sync_flags = (bFullFsync?SQLITE_SYNC_FULL:SQLITE_SYNC_NORMAL);
-  if( pPager->noSync ) pPager->needSync = 0;
+  if( pPager->noSync ){
+    pPager->syncFlags = 0;
+    pPager->ckptSyncFlags = 0;
+  }else if( bFullFsync ){
+    pPager->syncFlags = SQLITE_SYNC_FULL;
+    pPager->ckptSyncFlags = SQLITE_SYNC_FULL;
+  }else if( bCkptFullFsync ){
+    pPager->syncFlags = SQLITE_SYNC_NORMAL;
+    pPager->ckptSyncFlags = SQLITE_SYNC_FULL;
+  }else{
+    pPager->syncFlags = SQLITE_SYNC_NORMAL;
+    pPager->ckptSyncFlags = SQLITE_SYNC_NORMAL;
+  }
+  pPager->walSyncFlags = pPager->syncFlags;
+  if( pPager->fullSync ){
+    pPager->walSyncFlags |= WAL_SYNC_TRANSACTIONS;
+  }
 }
 #endif
 
@@ -32665,18 +40360,26 @@ SQLITE_API int sqlite3_opentemp_count = 0;
 #endif
 
 /*
-** Open a temporary file. 
+** Open a temporary file.
 **
-** Write the file descriptor into *fd.  Return SQLITE_OK on success or some
-** other error code if we fail. The OS will automatically delete the temporary
-** file when it is closed.
+** Write the file descriptor into *pFile. Return SQLITE_OK on success 
+** or some other error code if we fail. The OS will automatically 
+** delete the temporary file when it is closed.
+**
+** The flags passed to the VFS layer xOpen() call are those specified
+** by parameter vfsFlags ORed with the following:
+**
+**     SQLITE_OPEN_READWRITE
+**     SQLITE_OPEN_CREATE
+**     SQLITE_OPEN_EXCLUSIVE
+**     SQLITE_OPEN_DELETEONCLOSE
 */
-static int sqlite3PagerOpentemp(
+static int pagerOpentemp(
   Pager *pPager,        /* The pager object */
   sqlite3_file *pFile,  /* Write the file descriptor here */
   int vfsFlags          /* Flags passed through to the VFS */
 ){
-  int rc;
+  int rc;               /* Return code */
 
 #ifdef SQLITE_TEST
   sqlite3_opentemp_count++;  /* Used for testing and analysis only */
@@ -32685,295 +40388,116 @@ static int sqlite3PagerOpentemp(
   vfsFlags |=  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
             SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
   rc = sqlite3OsOpen(pPager->pVfs, 0, pFile, vfsFlags, 0);
-  assert( rc!=SQLITE_OK || pFile->pMethods );
+  assert( rc!=SQLITE_OK || isOpen(pFile) );
   return rc;
 }
 
-static int pagerStress(void *,PgHdr *);
-
-/*
-** Create a new page cache and put a pointer to the page cache in *ppPager.
-** The file to be cached need not exist.  The file is not locked until
-** the first call to sqlite3PagerGet() and is only held open until the
-** last page is released using sqlite3PagerUnref().
-**
-** If zFilename is NULL then a randomly-named temporary file is created
-** and used as the file to be cached.  The file will be deleted
-** automatically when it is closed.
-**
-** If zFilename is ":memory:" then all information is held in cache.
-** It is never written to disk.  This can be used to implement an
-** in-memory database.
-*/
-SQLITE_PRIVATE int sqlite3PagerOpen(
-  sqlite3_vfs *pVfs,       /* The virtual file system to use */
-  Pager **ppPager,         /* Return the Pager structure here */
-  const char *zFilename,   /* Name of the database file to open */
-  int nExtra,              /* Extra bytes append to each in-memory page */
-  int flags,               /* flags controlling this file */
-  int vfsFlags             /* flags passed through to sqlite3_vfs.xOpen() */
-){
-  u8 *pPtr;
-  Pager *pPager = 0;
-  int rc = SQLITE_OK;
-  int i;
-  int tempFile = 0;
-  int memDb = 0;
-  int readOnly = 0;
-  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
-  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
-  int journalFileSize;
-  int pcacheSize = sqlite3PcacheSize();
-  int szPageDflt = SQLITE_DEFAULT_PAGE_SIZE;
-  char *zPathname = 0;
-  int nPathname = 0;
-
-  if( sqlite3JournalSize(pVfs)>sqlite3MemJournalSize() ){
-    journalFileSize = sqlite3JournalSize(pVfs);
-  }else{
-    journalFileSize = sqlite3MemJournalSize();
-  }
-
-  /* The default return is a NULL pointer */
-  *ppPager = 0;
-
-  /* Compute and store the full pathname in an allocated buffer pointed
-  ** to by zPathname, length nPathname. Or, if this is a temporary file,
-  ** leave both nPathname and zPathname set to 0.
-  */
-  if( zFilename && zFilename[0] ){
-    nPathname = pVfs->mxPathname+1;
-    zPathname = sqlite3Malloc(nPathname*2);
-    if( zPathname==0 ){
-      return SQLITE_NOMEM;
-    }
-#ifndef SQLITE_OMIT_MEMORYDB
-    if( strcmp(zFilename,":memory:")==0 ){
-      memDb = 1;
-      zPathname[0] = 0;
-    }else
-#endif
-    {
-      rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
-    }
-    if( rc!=SQLITE_OK ){
-      sqlite3_free(zPathname);
-      return rc;
-    }
-    nPathname = sqlite3Strlen30(zPathname);
-  }
-
-  /* Allocate memory for the pager structure */
-  pPager = sqlite3MallocZero(
-    sizeof(*pPager) +           /* Pager structure */
-    pcacheSize      +           /* PCache object */
-    journalFileSize +           /* The journal file structure */ 
-    pVfs->szOsFile  +           /* The main db file */
-    journalFileSize * 2 +       /* The two journal files */ 
-    3*nPathname + 40            /* zFilename, zDirectory, zJournal */
-  );
-  if( !pPager ){
-    sqlite3_free(zPathname);
-    return SQLITE_NOMEM;
-  }
-  pPager->pPCache = (PCache *)&pPager[1];
-  pPtr = ((u8 *)&pPager[1]) + pcacheSize;
-  pPager->vfsFlags = vfsFlags;
-  pPager->fd = (sqlite3_file*)&pPtr[pVfs->szOsFile*0];
-  pPager->sjfd = (sqlite3_file*)&pPtr[pVfs->szOsFile];
-  pPager->jfd = (sqlite3_file*)&pPtr[pVfs->szOsFile+journalFileSize];
-  pPager->zFilename = (char*)&pPtr[pVfs->szOsFile+2*journalFileSize];
-  pPager->zDirectory = &pPager->zFilename[nPathname+1];
-  pPager->zJournal = &pPager->zDirectory[nPathname+1];
-  pPager->pVfs = pVfs;
-  if( zPathname ){
-    memcpy(pPager->zFilename, zPathname, nPathname+1);
-    sqlite3_free(zPathname);
-  }
-
-  /* Open the pager file.
-  */
-  if( zFilename && zFilename[0] && !memDb ){
-    if( nPathname>(pVfs->mxPathname - (int)sizeof("-journal")) ){
-      rc = SQLITE_CANTOPEN;
-    }else{
-      int fout = 0;
-      rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd,
-                         pPager->vfsFlags, &fout);
-      readOnly = (fout&SQLITE_OPEN_READONLY);
-
-      /* If the file was successfully opened for read/write access,
-      ** choose a default page size in case we have to create the
-      ** database file. The default page size is the maximum of:
-      **
-      **    + SQLITE_DEFAULT_PAGE_SIZE,
-      **    + The value returned by sqlite3OsSectorSize()
-      **    + The largest page size that can be written atomically.
-      */
-      if( rc==SQLITE_OK && !readOnly ){
-        setSectorSize(pPager);
-        if( szPageDflt<pPager->sectorSize ){
-          szPageDflt = pPager->sectorSize;
-        }
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
-        {
-          int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
-          int ii;
-          assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
-          assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
-          assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
-          for(ii=szPageDflt; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
-            if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ) szPageDflt = ii;
-          }
-        }
-#endif
-        if( szPageDflt>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
-          szPageDflt = SQLITE_MAX_DEFAULT_PAGE_SIZE;
-        }
-      }
-    }
-  }else{
-    /* If a temporary file is requested, it is not opened immediately.
-    ** In this case we accept the default page size and delay actually
-    ** opening the file until the first call to OsWrite().
-    **
-    ** This branch is also run for an in-memory database. An in-memory
-    ** database is the same as a temp-file that is never written out to
-    ** disk and uses an in-memory rollback journal.
-    */ 
-    tempFile = 1;
-    pPager->state = PAGER_EXCLUSIVE;
-  }
-
-  if( pPager && rc==SQLITE_OK ){
-    pPager->pTmpSpace = sqlite3PageMalloc(szPageDflt);
-  }
-
-  /* If an error occured in either of the blocks above.
-  ** Free the Pager structure and close the file.
-  ** Since the pager is not allocated there is no need to set 
-  ** any Pager.errMask variables.
-  */
-  if( !pPager || !pPager->pTmpSpace ){
-    sqlite3OsClose(pPager->fd);
-    sqlite3_free(pPager);
-    return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
-  }
-  nExtra = FORCE_ALIGNMENT(nExtra);
-  sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
-                    !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
-
-  PAGERTRACE(("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename));
-  IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))
-
-  /* Fill in Pager.zDirectory[] */
-  memcpy(pPager->zDirectory, pPager->zFilename, nPathname+1);
-  for(i=sqlite3Strlen30(pPager->zDirectory); 
-      i>0 && pPager->zDirectory[i-1]!='/'; i--){}
-  if( i>0 ) pPager->zDirectory[i-1] = 0;
-
-  /* Fill in Pager.zJournal[] */
-  if( zPathname ){
-    memcpy(pPager->zJournal, pPager->zFilename, nPathname);
-    memcpy(&pPager->zJournal[nPathname], "-journal", 9);
-  }else{
-    pPager->zJournal = 0;
-  }
-
-  /* pPager->journalOpen = 0; */
-  pPager->useJournal = (u8)useJournal;
-  pPager->noReadlock = (noReadlock && readOnly) ?1:0;
-  /* pPager->stmtOpen = 0; */
-  /* pPager->stmtInUse = 0; */
-  /* pPager->nRef = 0; */
-  pPager->dbSizeValid = (u8)memDb;
-  pPager->pageSize = szPageDflt;
-  /* pPager->stmtSize = 0; */
-  /* pPager->stmtJSize = 0; */
-  /* pPager->nPage = 0; */
-  pPager->mxPage = 100;
-  pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
-  /* pPager->state = PAGER_UNLOCK; */
-  assert( pPager->state == (tempFile ? PAGER_EXCLUSIVE : PAGER_UNLOCK) );
-  /* pPager->errMask = 0; */
-  pPager->tempFile = (u8)tempFile;
-  assert( tempFile==PAGER_LOCKINGMODE_NORMAL 
-          || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
-  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
-  pPager->exclusiveMode = (u8)tempFile; 
-  pPager->memDb = (u8)memDb;
-  pPager->readOnly = (u8)readOnly;
-  /* pPager->needSync = 0; */
-  pPager->noSync = (pPager->tempFile || !useJournal) ?1:0;
-  pPager->fullSync = pPager->noSync ?0:1;
-  pPager->sync_flags = SQLITE_SYNC_NORMAL;
-  /* pPager->pFirst = 0; */
-  /* pPager->pFirstSynced = 0; */
-  /* pPager->pLast = 0; */
-  pPager->nExtra = nExtra;
-  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
-  assert(pPager->fd->pMethods||tempFile);
-  setSectorSize(pPager);
-  if( memDb ){
-    pPager->journalMode = PAGER_JOURNALMODE_MEMORY;
-  }
-  /* pPager->xBusyHandler = 0; */
-  /* pPager->pBusyHandlerArg = 0; */
-  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
-  *ppPager = pPager;
-  return SQLITE_OK;
-}
-
 /*
 ** Set the busy handler function.
+**
+** The pager invokes the busy-handler if sqlite3OsLock() returns 
+** SQLITE_BUSY when trying to upgrade from no-lock to a SHARED lock,
+** or when trying to upgrade from a RESERVED lock to an EXCLUSIVE 
+** lock. It does *not* invoke the busy handler when upgrading from
+** SHARED to RESERVED, or when upgrading from SHARED to EXCLUSIVE
+** (which occurs during hot-journal rollback). Summary:
+**
+**   Transition                        | Invokes xBusyHandler
+**   --------------------------------------------------------
+**   NO_LOCK       -> SHARED_LOCK      | Yes
+**   SHARED_LOCK   -> RESERVED_LOCK    | No
+**   SHARED_LOCK   -> EXCLUSIVE_LOCK   | No
+**   RESERVED_LOCK -> EXCLUSIVE_LOCK   | Yes
+**
+** If the busy-handler callback returns non-zero, the lock is 
+** retried. If it returns zero, then the SQLITE_BUSY error is
+** returned to the caller of the pager API function.
 */
 SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(
-  Pager *pPager, 
-  int (*xBusyHandler)(void *),
-  void *pBusyHandlerArg
+  Pager *pPager,                       /* Pager object */
+  int (*xBusyHandler)(void *),         /* Pointer to busy-handler function */
+  void *pBusyHandlerArg                /* Argument to pass to xBusyHandler */
 ){  
   pPager->xBusyHandler = xBusyHandler;
   pPager->pBusyHandlerArg = pBusyHandlerArg;
 }
 
 /*
-** Set the reinitializer for this pager.  If not NULL, the reinitializer
-** is called when the content of a page in cache is restored to its original
-** value as a result of a rollback.  The callback gives higher-level code
-** an opportunity to restore the EXTRA section to agree with the restored
-** page data.
+** Change the page size used by the Pager object. The new page size 
+** is passed in *pPageSize.
+**
+** If the pager is in the error state when this function is called, it
+** is a no-op. The value returned is the error state error code (i.e. 
+** one of SQLITE_IOERR, an SQLITE_IOERR_xxx sub-code or SQLITE_FULL).
+**
+** Otherwise, if all of the following are true:
+**
+**   * the new page size (value of *pPageSize) is valid (a power 
+**     of two between 512 and SQLITE_MAX_PAGE_SIZE, inclusive), and
+**
+**   * there are no outstanding page references, and
+**
+**   * the database is either not an in-memory database or it is
+**     an in-memory database that currently consists of zero pages.
+**
+** then the pager object page size is set to *pPageSize.
+**
+** If the page size is changed, then this function uses sqlite3PagerMalloc() 
+** to obtain a new Pager.pTmpSpace buffer. If this allocation attempt 
+** fails, SQLITE_NOMEM is returned and the page size remains unchanged. 
+** In all other cases, SQLITE_OK is returned.
+**
+** If the page size is not changed, either because one of the enumerated
+** conditions above is not true, the pager was in error state when this
+** function was called, or because the memory allocation attempt failed, 
+** then *pPageSize is set to the old, retained page size before returning.
 */
-SQLITE_PRIVATE void sqlite3PagerSetReiniter(Pager *pPager, void (*xReinit)(DbPage*)){
-  pPager->xReiniter = xReinit;
-}
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager *pPager, u32 *pPageSize, int nReserve){
+  int rc = SQLITE_OK;
 
-/*
-** Set the page size to *pPageSize. If the suggest new page size is
-** inappropriate, then an alternative page size is set to that
-** value before returning.
-*/
-SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager *pPager, u16 *pPageSize){
-  int rc = pPager->errCode;
-  if( rc==SQLITE_OK ){
-    u16 pageSize = *pPageSize;
-    assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
-    if( pageSize && pageSize!=pPager->pageSize 
-     && (pPager->memDb==0 || pPager->dbSize==0)
-     && sqlite3PcacheRefCount(pPager->pPCache)==0 
-    ){
-      char *pNew = (char *)sqlite3PageMalloc(pageSize);
-      if( !pNew ){
-        rc = SQLITE_NOMEM;
-      }else{
-        pager_reset(pPager);
-        pPager->pageSize = pageSize;
-        if( !pPager->memDb ) setSectorSize(pPager);
-        sqlite3PageFree(pPager->pTmpSpace);
-        pPager->pTmpSpace = pNew;
-        sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
-      }
+  /* It is not possible to do a full assert_pager_state() here, as this
+  ** function may be called from within PagerOpen(), before the state
+  ** of the Pager object is internally consistent.
+  **
+  ** At one point this function returned an error if the pager was in 
+  ** PAGER_ERROR state. But since PAGER_ERROR state guarantees that
+  ** there is at least one outstanding page reference, this function
+  ** is a no-op for that case anyhow.
+  */
+
+  u32 pageSize = *pPageSize;
+  assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
+  if( (pPager->memDb==0 || pPager->dbSize==0)
+   && sqlite3PcacheRefCount(pPager->pPCache)==0 
+   && pageSize && pageSize!=(u32)pPager->pageSize 
+  ){
+    char *pNew = NULL;             /* New temp space */
+    i64 nByte = 0;
+
+    if( pPager->eState>PAGER_OPEN && isOpen(pPager->fd) ){
+      rc = sqlite3OsFileSize(pPager->fd, &nByte);
     }
-    *pPageSize = (u16)pPager->pageSize;
+    if( rc==SQLITE_OK ){
+      pNew = (char *)sqlite3PageMalloc(pageSize);
+      if( !pNew ) rc = SQLITE_NOMEM;
+    }
+
+    if( rc==SQLITE_OK ){
+      pager_reset(pPager);
+      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
+      pPager->pageSize = pageSize;
+      sqlite3PageFree(pPager->pTmpSpace);
+      pPager->pTmpSpace = pNew;
+      sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
+    }
+  }
+
+  *pPageSize = pPager->pageSize;
+  if( rc==SQLITE_OK ){
+    if( nReserve<0 ) nReserve = pPager->nReserve;
+    assert( nReserve>=0 && nReserve<1000 );
+    pPager->nReserve = (i16)nReserve;
+    pagerReportSize(pPager);
   }
   return rc;
 }
@@ -33001,7 +40525,8 @@ SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
   if( mxPage>0 ){
     pPager->mxPgno = mxPage;
   }
-  sqlite3PagerPagecount(pPager, 0);
+  assert( pPager->eState!=PAGER_OPEN );      /* Called only by OP_MaxPgcnt */
+  assert( pPager->mxPgno>=pPager->dbSize );  /* OP_MaxPgcnt enforces this */
   return pPager->mxPgno;
 }
 
@@ -33033,17 +40558,28 @@ void enable_simulated_io_errors(void){
 ** Read the first N bytes from the beginning of the file into memory
 ** that pDest points to. 
 **
-** No error checking is done. The rational for this is that this function 
-** may be called even if the file does not exist or contain a header. In 
-** these cases sqlite3OsRead() will return an error, to which the correct 
-** response is to zero the memory at pDest and continue.  A real IO error 
-** will presumably recur and be picked up later (Todo: Think about this).
+** If the pager was opened on a transient file (zFilename==""), or
+** opened on a file less than N bytes in size, the output buffer is
+** zeroed and SQLITE_OK returned. The rationale for this is that this 
+** function is used to read database headers, and a new transient or
+** zero sized database has a header than consists entirely of zeroes.
+**
+** If any IO error apart from SQLITE_IOERR_SHORT_READ is encountered,
+** the error code is returned to the caller and the contents of the
+** output buffer undefined.
 */
 SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
   int rc = SQLITE_OK;
   memset(pDest, 0, N);
-  assert(pPager->fd->pMethods||pPager->tempFile);
-  if( pPager->fd->pMethods ){
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+
+  /* This routine is only called by btree immediately after creating
+  ** the Pager object.  There has not been an opportunity to transition
+  ** to WAL mode yet.
+  */
+  assert( !pagerUseWal(pPager) );
+
+  if( isOpen(pPager->fd) ){
     IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
     rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
     if( rc==SQLITE_IOERR_SHORT_READ ){
@@ -33054,93 +40590,86 @@ SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned cha
 }
 
 /*
-** Return the total number of pages in the disk file associated with
-** pPager. 
+** This function may only be called when a read-transaction is open on
+** the pager. It returns the total number of pages in the database.
 **
-** If the PENDING_BYTE lies on the page directly after the end of the
-** file, then consider this page part of the file too. For example, if
-** PENDING_BYTE is byte 4096 (the first byte of page 5) and the size of the
-** file is 4096 bytes, 5 is returned instead of 4.
+** However, if the file is between 1 and <page-size> bytes in size, then 
+** this is considered a 1 page file.
 */
-SQLITE_PRIVATE int sqlite3PagerPagecount(Pager *pPager, int *pnPage){
-  i64 n = 0;
-  int rc;
-  assert( pPager!=0 );
-  if( pPager->errCode ){
-    rc = pPager->errCode;
-    return rc;
-  }
-  if( pPager->dbSizeValid ){
-    n = pPager->dbSize;
-  } else {
-    assert(pPager->fd->pMethods||pPager->tempFile);
-    if( (pPager->fd->pMethods)
-     && (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
-      pager_error(pPager, rc);
-      return rc;
-    }
-    if( n>0 && n<pPager->pageSize ){
-      n = 1;
-    }else{
-      n /= pPager->pageSize;
-    }
-    if( pPager->state!=PAGER_UNLOCK ){
-      pPager->dbSize = (Pgno)n;
-      pPager->dbFileSize = (Pgno)n;
-      pPager->dbSizeValid = 1;
-    }
-  }
-  if( n==(PENDING_BYTE/pPager->pageSize) ){
-    n++;
-  }
-  if( n>pPager->mxPgno ){
-    pPager->mxPgno = (Pgno)n;
-  }
-  if( pnPage ){
-    *pnPage = (int)n;
-  }
-  return SQLITE_OK;
+SQLITE_PRIVATE void sqlite3PagerPagecount(Pager *pPager, int *pnPage){
+  assert( pPager->eState>=PAGER_READER );
+  assert( pPager->eState!=PAGER_WRITER_FINISHED );
+  *pnPage = (int)pPager->dbSize;
 }
 
-/*
-** Forward declaration
-*/
-static int syncJournal(Pager*);
 
 /*
-** Try to obtain a lock on a file.  Invoke the busy callback if the lock
-** is currently not available.  Repeat until the busy callback returns
-** false or until the lock succeeds.
+** Try to obtain a lock of type locktype on the database file. If
+** a similar or greater lock is already held, this function is a no-op
+** (returning SQLITE_OK immediately).
+**
+** Otherwise, attempt to obtain the lock using sqlite3OsLock(). Invoke 
+** the busy callback if the lock is currently not available. Repeat 
+** until the busy callback returns false or until the attempt to 
+** obtain the lock succeeds.
 **
 ** Return SQLITE_OK on success and an error code if we cannot obtain
-** the lock.
+** the lock. If the lock is obtained successfully, set the Pager.state 
+** variable to locktype before returning.
 */
 static int pager_wait_on_lock(Pager *pPager, int locktype){
-  int rc;
+  int rc;                              /* Return code */
 
-  /* The OS lock values must be the same as the Pager lock values */
-  assert( PAGER_SHARED==SHARED_LOCK );
-  assert( PAGER_RESERVED==RESERVED_LOCK );
-  assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
+  /* Check that this is either a no-op (because the requested lock is 
+  ** already held, or one of the transistions that the busy-handler
+  ** may be invoked during, according to the comment above
+  ** sqlite3PagerSetBusyhandler().
+  */
+  assert( (pPager->eLock>=locktype)
+       || (pPager->eLock==NO_LOCK && locktype==SHARED_LOCK)
+       || (pPager->eLock==RESERVED_LOCK && locktype==EXCLUSIVE_LOCK)
+  );
 
-  /* If the file is currently unlocked then the size must be unknown */
-  assert( pPager->state>=PAGER_SHARED || pPager->dbSizeValid==0 );
-
-  if( pPager->state>=locktype ){
-    rc = SQLITE_OK;
-  }else{
-    do {
-      rc = sqlite3OsLock(pPager->fd, locktype);
-    }while( rc==SQLITE_BUSY && pPager->xBusyHandler(pPager->pBusyHandlerArg) );
-    if( rc==SQLITE_OK ){
-      pPager->state = (u8)locktype;
-      IOTRACE(("LOCK %p %d\n", pPager, locktype))
-    }
-  }
+  do {
+    rc = pagerLockDb(pPager, locktype);
+  }while( rc==SQLITE_BUSY && pPager->xBusyHandler(pPager->pBusyHandlerArg) );
   return rc;
 }
 
-#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Function assertTruncateConstraint(pPager) checks that one of the 
+** following is true for all dirty pages currently in the page-cache:
+**
+**   a) The page number is less than or equal to the size of the 
+**      current database image, in pages, OR
+**
+**   b) if the page content were written at this time, it would not
+**      be necessary to write the current content out to the sub-journal
+**      (as determined by function subjRequiresPage()).
+**
+** If the condition asserted by this function were not true, and the
+** dirty page were to be discarded from the cache via the pagerStress()
+** routine, pagerStress() would not write the current page content to
+** the database file. If a savepoint transaction were rolled back after
+** this happened, the correct behaviour would be to restore the current
+** content of the page. However, since this content is not present in either
+** the database file or the portion of the rollback journal and 
+** sub-journal rolled back the content could not be restored and the
+** database image would become corrupt. It is therefore fortunate that 
+** this circumstance cannot arise.
+*/
+#if defined(SQLITE_DEBUG)
+static void assertTruncateConstraintCb(PgHdr *pPg){
+  assert( pPg->flags&PGHDR_DIRTY );
+  assert( !subjRequiresPage(pPg) || pPg->pgno<=pPg->pPager->dbSize );
+}
+static void assertTruncateConstraint(Pager *pPager){
+  sqlite3PcacheIterateDirty(pPager->pPCache, assertTruncateConstraintCb);
+}
+#else
+# define assertTruncateConstraint(pPager)
+#endif
+
 /*
 ** Truncate the in-memory database file image to nPage pages. This 
 ** function does not actually modify the database file on disk. It 
@@ -33148,26 +40677,37 @@ static int pager_wait_on_lock(Pager *pPager, int locktype){
 ** truncation will be done when the current transaction is committed.
 */
 SQLITE_PRIVATE void sqlite3PagerTruncateImage(Pager *pPager, Pgno nPage){
-  assert( pPager->dbSizeValid );
   assert( pPager->dbSize>=nPage );
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
   pPager->dbSize = nPage;
+  assertTruncateConstraint(pPager);
 }
 
+
 /*
-** Return the current size of the database file image in pages. This
-** function differs from sqlite3PagerPagecount() in two ways:
+** This function is called before attempting a hot-journal rollback. It
+** syncs the journal file to disk, then sets pPager->journalHdr to the
+** size of the journal file so that the pager_playback() routine knows
+** that the entire journal file has been synced.
 **
-**  a) It may only be called when at least one reference to a database
-**     page is held. This guarantees that the database size is already
-**     known and a call to sqlite3OsFileSize() is not required.
+** Syncing a hot-journal to disk before attempting to roll it back ensures 
+** that if a power-failure occurs during the rollback, the process that
+** attempts rollback following system recovery sees the same journal
+** content as this process.
 **
-**  b) The return value is not adjusted for the locking page.
+** If everything goes as planned, SQLITE_OK is returned. Otherwise, 
+** an SQLite error code.
 */
-SQLITE_PRIVATE Pgno sqlite3PagerImageSize(Pager *pPager){
-  assert( pPager->dbSizeValid );
-  return pPager->dbSize;
+static int pagerSyncHotJournal(Pager *pPager){
+  int rc = SQLITE_OK;
+  if( !pPager->noSync ){
+    rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_NORMAL);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3OsFileSize(pPager->jfd, &pPager->journalHdr);
+  }
+  return rc;
 }
-#endif  /* ifndef SQLITE_OMIT_AUTOVACUUM */
 
 /*
 ** Shutdown the page cache.  Free all memory and close all files.
@@ -33184,110 +40724,133 @@ SQLITE_PRIVATE Pgno sqlite3PagerImageSize(Pager *pPager){
 ** to the caller.
 */
 SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager){
+  u8 *pTmp = (u8 *)pPager->pTmpSpace;
 
+  assert( assert_pager_state(pPager) );
   disable_simulated_io_errors();
   sqlite3BeginBenignMalloc();
-  pPager->errCode = 0;
+  /* pPager->errCode = 0; */
   pPager->exclusiveMode = 0;
+#ifndef SQLITE_OMIT_WAL
+  sqlite3WalClose(pPager->pWal, pPager->ckptSyncFlags, pPager->pageSize, pTmp);
+  pPager->pWal = 0;
+#endif
   pager_reset(pPager);
-  if( !MEMDB ){
-    /* Set Pager.journalHdr to -1 for the benefit of the pager_playback() 
-    ** call which may be made from within pagerUnlockAndRollback(). If it
-    ** is not -1, then the unsynced portion of an open journal file may
-    ** be played back into the database. If a power failure occurs while
-    ** this is happening, the database may become corrupt.
+  if( MEMDB ){
+    pager_unlock(pPager);
+  }else{
+    /* If it is open, sync the journal file before calling UnlockAndRollback.
+    ** If this is not done, then an unsynced portion of the open journal 
+    ** file may be played back into the database. If a power failure occurs 
+    ** while this is happening, the database could become corrupt.
+    **
+    ** If an error occurs while trying to sync the journal, shift the pager
+    ** into the ERROR state. This causes UnlockAndRollback to unlock the
+    ** database and close the journal file without attempting to roll it
+    ** back or finalize it. The next database user will have to do hot-journal
+    ** rollback before accessing the database file.
     */
-    pPager->journalHdr = -1;
+    if( isOpen(pPager->jfd) ){
+      pager_error(pPager, pagerSyncHotJournal(pPager));
+    }
     pagerUnlockAndRollback(pPager);
   }
-  enable_simulated_io_errors();
   sqlite3EndBenignMalloc();
+  enable_simulated_io_errors();
   PAGERTRACE(("CLOSE %d\n", PAGERID(pPager)));
   IOTRACE(("CLOSE %p\n", pPager))
-  if( pPager->journalOpen ){
-    sqlite3OsClose(pPager->jfd);
-  }
-  sqlite3BitvecDestroy(pPager->pInJournal);
-  sqlite3BitvecDestroy(pPager->pAlwaysRollback);
-  releaseAllSavepoint(pPager);
+  sqlite3OsClose(pPager->jfd);
   sqlite3OsClose(pPager->fd);
-  /* Temp files are automatically deleted by the OS
-  ** if( pPager->tempFile ){
-  **   sqlite3OsDelete(pPager->zFilename);
-  ** }
-  */
-
-  sqlite3PageFree(pPager->pTmpSpace);
+  sqlite3PageFree(pTmp);
   sqlite3PcacheClose(pPager->pPCache);
+
+#ifdef SQLITE_HAS_CODEC
+  if( pPager->xCodecFree ) pPager->xCodecFree(pPager->pCodec);
+#endif
+
+  assert( !pPager->aSavepoint && !pPager->pInJournal );
+  assert( !isOpen(pPager->jfd) && !isOpen(pPager->sjfd) );
+
   sqlite3_free(pPager);
   return SQLITE_OK;
 }
 
 #if !defined(NDEBUG) || defined(SQLITE_TEST)
 /*
-** Return the page number for the given page data.
+** Return the page number for page pPg.
 */
-SQLITE_PRIVATE Pgno sqlite3PagerPagenumber(DbPage *p){
-  return p->pgno;
+SQLITE_PRIVATE Pgno sqlite3PagerPagenumber(DbPage *pPg){
+  return pPg->pgno;
 }
 #endif
 
 /*
-** Increment the reference count for a page.  The input pointer is
-** a reference to the page data.
+** Increment the reference count for page pPg.
 */
-SQLITE_PRIVATE int sqlite3PagerRef(DbPage *pPg){
+SQLITE_PRIVATE void sqlite3PagerRef(DbPage *pPg){
   sqlite3PcacheRef(pPg);
-  return SQLITE_OK;
 }
 
 /*
-** Sync the journal.  In other words, make sure all the pages that have
+** Sync the journal. In other words, make sure all the pages that have
 ** been written to the journal have actually reached the surface of the
-** disk.  It is not safe to modify the original database file until after
-** the journal has been synced.  If the original database is modified before
-** the journal is synced and a power failure occurs, the unsynced journal
-** data would be lost and we would be unable to completely rollback the
-** database changes.  Database corruption would occur.
-** 
-** This routine also updates the nRec field in the header of the journal.
-** (See comments on the pager_playback() routine for additional information.)
-** If the sync mode is FULL, two syncs will occur.  First the whole journal
-** is synced, then the nRec field is updated, then a second sync occurs.
+** disk and can be restored in the event of a hot-journal rollback.
 **
-** For temporary databases, we do not care if we are able to rollback
-** after a power failure, so no sync occurs.
+** If the Pager.noSync flag is set, then this function is a no-op.
+** Otherwise, the actions required depend on the journal-mode and the 
+** device characteristics of the file-system, as follows:
 **
-** If the IOCAP_SEQUENTIAL flag is set for the persistent media on which
-** the database is stored, then OsSync() is never called on the journal
-** file. In this case all that is required is to update the nRec field in
-** the journal header.
+**   * If the journal file is an in-memory journal file, no action need
+**     be taken.
 **
-** This routine clears the needSync field of every page current held in
-** memory.
+**   * Otherwise, if the device does not support the SAFE_APPEND property,
+**     then the nRec field of the most recently written journal header
+**     is updated to contain the number of journal records that have
+**     been written following it. If the pager is operating in full-sync
+**     mode, then the journal file is synced before this field is updated.
+**
+**   * If the device does not support the SEQUENTIAL property, then 
+**     journal file is synced.
+**
+** Or, in pseudo-code:
+**
+**   if( NOT <in-memory journal> ){
+**     if( NOT SAFE_APPEND ){
+**       if( <full-sync mode> ) xSync(<journal file>);
+**       <update nRec field>
+**     } 
+**     if( NOT SEQUENTIAL ) xSync(<journal file>);
+**   }
+**
+** If successful, this routine clears the PGHDR_NEED_SYNC flag of every 
+** page currently held in memory before returning SQLITE_OK. If an IO
+** error is encountered, then the IO error code is returned to the caller.
 */
-static int syncJournal(Pager *pPager){
-  int rc = SQLITE_OK;
+static int syncJournal(Pager *pPager, int newHdr){
+  int rc;                         /* Return code */
 
-  /* Sync the journal before modifying the main database
-  ** (assuming there is a journal and it needs to be synced.)
-  */
-  if( pPager->needSync ){
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+  assert( !pagerUseWal(pPager) );
+
+  rc = sqlite3PagerExclusiveLock(pPager);
+  if( rc!=SQLITE_OK ) return rc;
+
+  if( !pPager->noSync ){
     assert( !pPager->tempFile );
-    if( pPager->journalMode!=PAGER_JOURNALMODE_MEMORY ){
-      int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
-      assert( pPager->journalOpen );
+    if( isOpen(pPager->jfd) && pPager->journalMode!=PAGER_JOURNALMODE_MEMORY ){
+      const int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+      assert( isOpen(pPager->jfd) );
 
       if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
-        i64 jrnlOff = journalHdrOffset(pPager);
-        u8 zMagic[8];
-
         /* This block deals with an obscure problem. If the last connection
         ** that wrote to this database was operating in persistent-journal
         ** mode, then the journal file may at this point actually be larger
         ** than Pager.journalOff bytes. If the next thing in the journal
         ** file happens to be a journal-header (written as part of the
-        ** previous connections transaction), and a crash or power-failure 
+        ** previous connection's transaction), and a crash or power-failure 
         ** occurs after nRec is updated but before this connection writes 
         ** anything else to the journal file (or commits/rolls back its 
         ** transaction), then SQLite may become confused when doing the 
@@ -33298,11 +40861,24 @@ static int syncJournal(Pager *pPager){
         ** To work around this, if the journal file does appear to contain
         ** a valid header following Pager.journalOff, then write a 0x00
         ** byte to the start of it to prevent it from being recognized.
+        **
+        ** Variable iNextHdrOffset is set to the offset at which this
+        ** problematic header will occur, if it exists. aMagic is used 
+        ** as a temporary buffer to inspect the first couple of bytes of
+        ** the potential journal header.
         */
-        rc = sqlite3OsRead(pPager->jfd, zMagic, 8, jrnlOff);
-        if( rc==SQLITE_OK && 0==memcmp(zMagic, aJournalMagic, 8) ){
+        i64 iNextHdrOffset;
+        u8 aMagic[8];
+        u8 zHeader[sizeof(aJournalMagic)+4];
+
+        memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
+        put32bits(&zHeader[sizeof(aJournalMagic)], pPager->nRec);
+
+        iNextHdrOffset = journalHdrOffset(pPager);
+        rc = sqlite3OsRead(pPager->jfd, aMagic, 8, iNextHdrOffset);
+        if( rc==SQLITE_OK && 0==memcmp(aMagic, aJournalMagic, 8) ){
           static const u8 zerobyte = 0;
-          rc = sqlite3OsWrite(pPager->jfd, &zerobyte, 1, jrnlOff);
+          rc = sqlite3OsWrite(pPager->jfd, &zerobyte, 1, iNextHdrOffset);
         }
         if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
           return rc;
@@ -33322,401 +40898,941 @@ static int syncJournal(Pager *pPager){
         if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
           PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
           IOTRACE(("JSYNC %p\n", pPager))
-          rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags);
-          if( rc!=0 ) return rc;
+          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
+          if( rc!=SQLITE_OK ) return rc;
         }
-
-        jrnlOff = pPager->journalHdr + sizeof(aJournalMagic);
-        IOTRACE(("JHDR %p %lld %d\n", pPager, jrnlOff, 4));
-        rc = write32bits(pPager->jfd, jrnlOff, pPager->nRec);
-        if( rc ) return rc;
+        IOTRACE(("JHDR %p %lld\n", pPager, pPager->journalHdr));
+        rc = sqlite3OsWrite(
+            pPager->jfd, zHeader, sizeof(zHeader), pPager->journalHdr
+        );
+        if( rc!=SQLITE_OK ) return rc;
       }
       if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
         PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
         IOTRACE(("JSYNC %p\n", pPager))
-        rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags| 
-          (pPager->sync_flags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
+        rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags| 
+          (pPager->syncFlags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
         );
-        if( rc!=0 ) return rc;
+        if( rc!=SQLITE_OK ) return rc;
       }
-      pPager->journalStarted = 1;
-    }
-    pPager->needSync = 0;
 
-    /* Erase the needSync flag from every page.
+      pPager->journalHdr = pPager->journalOff;
+      if( newHdr && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
+        pPager->nRec = 0;
+        rc = writeJournalHdr(pPager);
+        if( rc!=SQLITE_OK ) return rc;
+      }
+    }else{
+      pPager->journalHdr = pPager->journalOff;
+    }
+  }
+
+  /* Unless the pager is in noSync mode, the journal file was just 
+  ** successfully synced. Either way, clear the PGHDR_NEED_SYNC flag on 
+  ** all pages.
+  */
+  sqlite3PcacheClearSyncFlags(pPager->pPCache);
+  pPager->eState = PAGER_WRITER_DBMOD;
+  assert( assert_pager_state(pPager) );
+  return SQLITE_OK;
+}
+
+/*
+** The argument is the first in a linked list of dirty pages connected
+** by the PgHdr.pDirty pointer. This function writes each one of the
+** in-memory pages in the list to the database file. The argument may
+** be NULL, representing an empty list. In this case this function is
+** a no-op.
+**
+** The pager must hold at least a RESERVED lock when this function
+** is called. Before writing anything to the database file, this lock
+** is upgraded to an EXCLUSIVE lock. If the lock cannot be obtained,
+** SQLITE_BUSY is returned and no data is written to the database file.
+** 
+** If the pager is a temp-file pager and the actual file-system file
+** is not yet open, it is created and opened before any data is 
+** written out.
+**
+** Once the lock has been upgraded and, if necessary, the file opened,
+** the pages are written out to the database file in list order. Writing
+** a page is skipped if it meets either of the following criteria:
+**
+**   * The page number is greater than Pager.dbSize, or
+**   * The PGHDR_DONT_WRITE flag is set on the page.
+**
+** If writing out a page causes the database file to grow, Pager.dbFileSize
+** is updated accordingly. If page 1 is written out, then the value cached
+** in Pager.dbFileVers[] is updated to match the new value stored in
+** the database file.
+**
+** If everything is successful, SQLITE_OK is returned. If an IO error 
+** occurs, an IO error code is returned. Or, if the EXCLUSIVE lock cannot
+** be obtained, SQLITE_BUSY is returned.
+*/
+static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
+  int rc = SQLITE_OK;                  /* Return code */
+
+  /* This function is only called for rollback pagers in WRITER_DBMOD state. */
+  assert( !pagerUseWal(pPager) );
+  assert( pPager->eState==PAGER_WRITER_DBMOD );
+  assert( pPager->eLock==EXCLUSIVE_LOCK );
+
+  /* If the file is a temp-file has not yet been opened, open it now. It
+  ** is not possible for rc to be other than SQLITE_OK if this branch
+  ** is taken, as pager_wait_on_lock() is a no-op for temp-files.
+  */
+  if( !isOpen(pPager->fd) ){
+    assert( pPager->tempFile && rc==SQLITE_OK );
+    rc = pagerOpentemp(pPager, pPager->fd, pPager->vfsFlags);
+  }
+
+  /* Before the first write, give the VFS a hint of what the final
+  ** file size will be.
+  */
+  assert( rc!=SQLITE_OK || isOpen(pPager->fd) );
+  if( rc==SQLITE_OK && pPager->dbSize>pPager->dbHintSize ){
+    sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
+    pPager->dbHintSize = pPager->dbSize;
+  }
+
+  while( rc==SQLITE_OK && pList ){
+    Pgno pgno = pList->pgno;
+
+    /* If there are dirty pages in the page cache with page numbers greater
+    ** than Pager.dbSize, this means sqlite3PagerTruncateImage() was called to
+    ** make the file smaller (presumably by auto-vacuum code). Do not write
+    ** any such pages to the file.
+    **
+    ** Also, do not write out any page that has the PGHDR_DONT_WRITE flag
+    ** set (set by sqlite3PagerDontWrite()).
     */
-    sqlite3PcacheClearSyncFlags(pPager->pPCache);
+    if( pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
+      i64 offset = (pgno-1)*(i64)pPager->pageSize;   /* Offset to write */
+      char *pData;                                   /* Data to write */    
+
+      assert( (pList->flags&PGHDR_NEED_SYNC)==0 );
+      if( pList->pgno==1 ) pager_write_changecounter(pList);
+
+      /* Encode the database */
+      CODEC2(pPager, pList->pData, pgno, 6, return SQLITE_NOMEM, pData);
+
+      /* Write out the page data. */
+      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
+
+      /* If page 1 was just written, update Pager.dbFileVers to match
+      ** the value now stored in the database file. If writing this 
+      ** page caused the database file to grow, update dbFileSize. 
+      */
+      if( pgno==1 ){
+        memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
+      }
+      if( pgno>pPager->dbFileSize ){
+        pPager->dbFileSize = pgno;
+      }
+      pPager->aStat[PAGER_STAT_WRITE]++;
+
+      /* Update any backup objects copying the contents of this pager. */
+      sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)pList->pData);
+
+      PAGERTRACE(("STORE %d page %d hash(%08x)\n",
+                   PAGERID(pPager), pgno, pager_pagehash(pList)));
+      IOTRACE(("PGOUT %p %d\n", pPager, pgno));
+      PAGER_INCR(sqlite3_pager_writedb_count);
+    }else{
+      PAGERTRACE(("NOSTORE %d page %d\n", PAGERID(pPager), pgno));
+    }
+    pager_set_pagehash(pList);
+    pList = pList->pDirty;
   }
 
   return rc;
 }
 
 /*
-** Given a list of pages (connected by the PgHdr.pDirty pointer) write
-** every one of those pages out to the database file. No calls are made
-** to the page-cache to mark the pages as clean. It is the responsibility
-** of the caller to use PcacheCleanAll() or PcacheMakeClean() to mark
-** the pages as clean.
+** Ensure that the sub-journal file is open. If it is already open, this 
+** function is a no-op.
+**
+** SQLITE_OK is returned if everything goes according to plan. An 
+** SQLITE_IOERR_XXX error code is returned if a call to sqlite3OsOpen() 
+** fails.
 */
-static int pager_write_pagelist(PgHdr *pList){
-  Pager *pPager;
-  int rc;
-
-  if( pList==0 ) return SQLITE_OK;
-  pPager = pList->pPager;
-
-  /* At this point there may be either a RESERVED or EXCLUSIVE lock on the
-  ** database file. If there is already an EXCLUSIVE lock, the following
-  ** calls to sqlite3OsLock() are no-ops.
-  **
-  ** Moving the lock from RESERVED to EXCLUSIVE actually involves going
-  ** through an intermediate state PENDING.   A PENDING lock prevents new
-  ** readers from attaching to the database but is unsufficient for us to
-  ** write.  The idea of a PENDING lock is to prevent new readers from
-  ** coming in while we wait for existing readers to clear.
-  **
-  ** While the pager is in the RESERVED state, the original database file
-  ** is unchanged and we can rollback without having to playback the
-  ** journal into the original database file.  Once we transition to
-  ** EXCLUSIVE, it means the database file has been changed and any rollback
-  ** will require a journal playback.
-  */
-  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
-  if( rc!=SQLITE_OK ){
-    return rc;
+static int openSubJournal(Pager *pPager){
+  int rc = SQLITE_OK;
+  if( !isOpen(pPager->sjfd) ){
+    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY || pPager->subjInMemory ){
+      sqlite3MemJournalOpen(pPager->sjfd);
+    }else{
+      rc = pagerOpentemp(pPager, pPager->sjfd, SQLITE_OPEN_SUBJOURNAL);
+    }
   }
-
-  while( pList ){
-
-    /* If the file has not yet been opened, open it now. */
-    if( !pPager->fd->pMethods ){
-      assert(pPager->tempFile);
-      rc = sqlite3PagerOpentemp(pPager, pPager->fd, pPager->vfsFlags);
-      if( rc ) return rc;
-    }
-
-    /* If there are dirty pages in the page cache with page numbers greater
-    ** than Pager.dbSize, this means sqlite3PagerTruncateImage() was called to
-    ** make the file smaller (presumably by auto-vacuum code). Do not write
-    ** any such pages to the file.
-    */
-    if( pList->pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
-      i64 offset = (pList->pgno-1)*(i64)pPager->pageSize;
-      char *pData = CODEC2(pPager, pList->pData, pList->pgno, 6);
-
-      PAGERTRACE(("STORE %d page %d hash(%08x)\n",
-                   PAGERID(pPager), pList->pgno, pager_pagehash(pList)));
-      IOTRACE(("PGOUT %p %d\n", pPager, pList->pgno));
-      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
-      PAGER_INCR(sqlite3_pager_writedb_count);
-      PAGER_INCR(pPager->nWrite);
-      if( pList->pgno==1 ){
-        memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
-      }
-      if( pList->pgno>pPager->dbFileSize ){
-        pPager->dbFileSize = pList->pgno;
-      }
-    }
-#ifndef NDEBUG
-    else{
-      PAGERTRACE(("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno));
-    }
-#endif
-    if( rc ) return rc;
-#ifdef SQLITE_CHECK_PAGES
-    pList->pageHash = pager_pagehash(pList);
-#endif
-    pList = pList->pDirty;
-  }
-
-  return SQLITE_OK;
+  return rc;
 }
 
 /*
-** Add the page to the sub-journal. It is the callers responsibility to
-** use subjRequiresPage() to check that it is really required before 
-** calling this function.
+** Append a record of the current state of page pPg to the sub-journal. 
+** It is the callers responsibility to use subjRequiresPage() to check 
+** that it is really required before calling this function.
+**
+** If successful, set the bit corresponding to pPg->pgno in the bitvecs
+** for all open savepoints before returning.
+**
+** This function returns SQLITE_OK if everything is successful, an IO
+** error code if the attempt to write to the sub-journal fails, or 
+** SQLITE_NOMEM if a malloc fails while setting a bit in a savepoint
+** bitvec.
 */
 static int subjournalPage(PgHdr *pPg){
-  int rc;
-  void *pData = pPg->pData;
+  int rc = SQLITE_OK;
   Pager *pPager = pPg->pPager;
-  i64 offset = pPager->stmtNRec*(4+pPager->pageSize);
-  char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
+  if( pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
 
-  PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
+    /* Open the sub-journal, if it has not already been opened */
+    assert( pPager->useJournal );
+    assert( isOpen(pPager->jfd) || pagerUseWal(pPager) );
+    assert( isOpen(pPager->sjfd) || pPager->nSubRec==0 );
+    assert( pagerUseWal(pPager) 
+         || pageInJournal(pPg) 
+         || pPg->pgno>pPager->dbOrigSize 
+    );
+    rc = openSubJournal(pPager);
 
-  assert( pageInJournal(pPg) || pPg->pgno>pPager->dbOrigSize );
-  rc = write32bits(pPager->sjfd, offset, pPg->pgno);
-  if( rc==SQLITE_OK ){
-    rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
+    /* If the sub-journal was opened successfully (or was already open),
+    ** write the journal record into the file.  */
+    if( rc==SQLITE_OK ){
+      void *pData = pPg->pData;
+      i64 offset = (i64)pPager->nSubRec*(4+pPager->pageSize);
+      char *pData2;
+  
+      CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
+      PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
+      rc = write32bits(pPager->sjfd, offset, pPg->pgno);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
+      }
+    }
   }
   if( rc==SQLITE_OK ){
-    pPager->stmtNRec++;
+    pPager->nSubRec++;
     assert( pPager->nSavepoint>0 );
     rc = addToSavepointBitvecs(pPager, pPg->pgno);
   }
   return rc;
 }
 
-
 /*
 ** This function is called by the pcache layer when it has reached some
-** soft memory limit. The argument is a pointer to a purgeable Pager 
-** object. This function attempts to make a single dirty page that has no
-** outstanding references (if one exists) clean so that it can be recycled 
-** by the pcache layer.
+** soft memory limit. The first argument is a pointer to a Pager object
+** (cast as a void*). The pager is always 'purgeable' (not an in-memory
+** database). The second argument is a reference to a page that is 
+** currently dirty but has no outstanding references. The page
+** is always associated with the Pager object passed as the first 
+** argument.
+**
+** The job of this function is to make pPg clean by writing its contents
+** out to the database file, if possible. This may involve syncing the
+** journal file. 
+**
+** If successful, sqlite3PcacheMakeClean() is called on the page and
+** SQLITE_OK returned. If an IO error occurs while trying to make the
+** page clean, the IO error code is returned. If the page cannot be
+** made clean for some other reason, but no error occurs, then SQLITE_OK
+** is returned by sqlite3PcacheMakeClean() is not called.
 */
 static int pagerStress(void *p, PgHdr *pPg){
   Pager *pPager = (Pager *)p;
   int rc = SQLITE_OK;
 
-  if( pPager->doNotSync ){
+  assert( pPg->pPager==pPager );
+  assert( pPg->flags&PGHDR_DIRTY );
+
+  /* The doNotSyncSpill flag is set during times when doing a sync of
+  ** journal (and adding a new header) is not allowed.  This occurs
+  ** during calls to sqlite3PagerWrite() while trying to journal multiple
+  ** pages belonging to the same sector.
+  **
+  ** The doNotSpill flag inhibits all cache spilling regardless of whether
+  ** or not a sync is required.  This is set during a rollback.
+  **
+  ** Spilling is also prohibited when in an error state since that could
+  ** lead to database corruption.   In the current implementaton it 
+  ** is impossible for sqlite3PcacheFetch() to be called with createFlag==1
+  ** while in the error state, hence it is impossible for this routine to
+  ** be called in the error state.  Nevertheless, we include a NEVER()
+  ** test for the error state as a safeguard against future changes.
+  */
+  if( NEVER(pPager->errCode) ) return SQLITE_OK;
+  if( pPager->doNotSpill ) return SQLITE_OK;
+  if( pPager->doNotSyncSpill && (pPg->flags & PGHDR_NEED_SYNC)!=0 ){
     return SQLITE_OK;
   }
 
-  assert( pPg->flags&PGHDR_DIRTY );
-  if( pPager->errCode==SQLITE_OK ){
-    if( pPg->flags&PGHDR_NEED_SYNC ){
-      rc = syncJournal(pPager);
-      if( rc==SQLITE_OK && pPager->fullSync && 
-        !(pPager->journalMode==PAGER_JOURNALMODE_MEMORY) &&
-        !(sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
-      ){
-        pPager->nRec = 0;
-        rc = writeJournalHdr(pPager);
-      }
+  pPg->pDirty = 0;
+  if( pagerUseWal(pPager) ){
+    /* Write a single frame for this page to the log. */
+    if( subjRequiresPage(pPg) ){ 
+      rc = subjournalPage(pPg); 
     }
     if( rc==SQLITE_OK ){
-      pPg->pDirty = 0;
-      if( pPg->pgno>pPager->dbSize && subjRequiresPage(pPg) ){
-        rc = subjournalPage(pPg);
-      }
-      if( rc==SQLITE_OK ){
-        rc = pager_write_pagelist(pPg);
-      }
+      rc = pagerWalFrames(pPager, pPg, 0, 0);
     }
-    if( rc!=SQLITE_OK ){
-      pager_error(pPager, rc);
+  }else{
+  
+    /* Sync the journal file if required. */
+    if( pPg->flags&PGHDR_NEED_SYNC 
+     || pPager->eState==PAGER_WRITER_CACHEMOD
+    ){
+      rc = syncJournal(pPager, 1);
+    }
+  
+    /* If the page number of this page is larger than the current size of
+    ** the database image, it may need to be written to the sub-journal.
+    ** This is because the call to pager_write_pagelist() below will not
+    ** actually write data to the file in this case.
+    **
+    ** Consider the following sequence of events:
+    **
+    **   BEGIN;
+    **     <journal page X>
+    **     <modify page X>
+    **     SAVEPOINT sp;
+    **       <shrink database file to Y pages>
+    **       pagerStress(page X)
+    **     ROLLBACK TO sp;
+    **
+    ** If (X>Y), then when pagerStress is called page X will not be written
+    ** out to the database file, but will be dropped from the cache. Then,
+    ** following the "ROLLBACK TO sp" statement, reading page X will read
+    ** data from the database file. This will be the copy of page X as it
+    ** was when the transaction started, not as it was when "SAVEPOINT sp"
+    ** was executed.
+    **
+    ** The solution is to write the current data for page X into the 
+    ** sub-journal file now (if it is not already there), so that it will
+    ** be restored to its current value when the "ROLLBACK TO sp" is 
+    ** executed.
+    */
+    if( NEVER(
+        rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg)
+    ) ){
+      rc = subjournalPage(pPg);
+    }
+  
+    /* Write the contents of the page out to the database file. */
+    if( rc==SQLITE_OK ){
+      assert( (pPg->flags&PGHDR_NEED_SYNC)==0 );
+      rc = pager_write_pagelist(pPager, pPg);
     }
   }
 
+  /* Mark the page as clean. */
   if( rc==SQLITE_OK ){
     PAGERTRACE(("STRESS %d page %d\n", PAGERID(pPager), pPg->pgno));
     sqlite3PcacheMakeClean(pPg);
   }
-  return rc;
+
+  return pager_error(pPager, rc); 
 }
 
 
 /*
-** Return 1 if there is a hot journal on the given pager.
-** A hot journal is one that needs to be played back.
+** Allocate and initialize a new Pager object and put a pointer to it
+** in *ppPager. The pager should eventually be freed by passing it
+** to sqlite3PagerClose().
+**
+** The zFilename argument is the path to the database file to open.
+** If zFilename is NULL then a randomly-named temporary file is created
+** and used as the file to be cached. Temporary files are be deleted
+** automatically when they are closed. If zFilename is ":memory:" then 
+** all information is held in cache. It is never written to disk. 
+** This can be used to implement an in-memory database.
+**
+** The nExtra parameter specifies the number of bytes of space allocated
+** along with each page reference. This space is available to the user
+** via the sqlite3PagerGetExtra() API.
+**
+** The flags argument is used to specify properties that affect the
+** operation of the pager. It should be passed some bitwise combination
+** of the PAGER_* flags.
+**
+** The vfsFlags parameter is a bitmask to pass to the flags parameter
+** of the xOpen() method of the supplied VFS when opening files. 
+**
+** If the pager object is allocated and the specified file opened 
+** successfully, SQLITE_OK is returned and *ppPager set to point to
+** the new pager object. If an error occurs, *ppPager is set to NULL
+** and error code returned. This function may return SQLITE_NOMEM
+** (sqlite3Malloc() is used to allocate memory), SQLITE_CANTOPEN or 
+** various SQLITE_IO_XXX errors.
+*/
+SQLITE_PRIVATE int sqlite3PagerOpen(
+  sqlite3_vfs *pVfs,       /* The virtual file system to use */
+  Pager **ppPager,         /* OUT: Return the Pager structure here */
+  const char *zFilename,   /* Name of the database file to open */
+  int nExtra,              /* Extra bytes append to each in-memory page */
+  int flags,               /* flags controlling this file */
+  int vfsFlags,            /* flags passed through to sqlite3_vfs.xOpen() */
+  void (*xReinit)(DbPage*) /* Function to reinitialize pages */
+){
+  u8 *pPtr;
+  Pager *pPager = 0;       /* Pager object to allocate and return */
+  int rc = SQLITE_OK;      /* Return code */
+  int tempFile = 0;        /* True for temp files (incl. in-memory files) */
+  int memDb = 0;           /* True if this is an in-memory file */
+  int readOnly = 0;        /* True if this is a read-only file */
+  int journalFileSize;     /* Bytes to allocate for each journal fd */
+  char *zPathname = 0;     /* Full path to database file */
+  int nPathname = 0;       /* Number of bytes in zPathname */
+  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0; /* False to omit journal */
+  int pcacheSize = sqlite3PcacheSize();       /* Bytes to allocate for PCache */
+  u32 szPageDflt = SQLITE_DEFAULT_PAGE_SIZE;  /* Default page size */
+  const char *zUri = 0;    /* URI args to copy */
+  int nUri = 0;            /* Number of bytes of URI args at *zUri */
+
+  /* Figure out how much space is required for each journal file-handle
+  ** (there are two of them, the main journal and the sub-journal). This
+  ** is the maximum space required for an in-memory journal file handle 
+  ** and a regular journal file-handle. Note that a "regular journal-handle"
+  ** may be a wrapper capable of caching the first portion of the journal
+  ** file in memory to implement the atomic-write optimization (see 
+  ** source file journal.c).
+  */
+  if( sqlite3JournalSize(pVfs)>sqlite3MemJournalSize() ){
+    journalFileSize = ROUND8(sqlite3JournalSize(pVfs));
+  }else{
+    journalFileSize = ROUND8(sqlite3MemJournalSize());
+  }
+
+  /* Set the output variable to NULL in case an error occurs. */
+  *ppPager = 0;
+
+#ifndef SQLITE_OMIT_MEMORYDB
+  if( flags & PAGER_MEMORY ){
+    memDb = 1;
+    if( zFilename && zFilename[0] ){
+      zPathname = sqlite3DbStrDup(0, zFilename);
+      if( zPathname==0  ) return SQLITE_NOMEM;
+      nPathname = sqlite3Strlen30(zPathname);
+      zFilename = 0;
+    }
+  }
+#endif
+
+  /* Compute and store the full pathname in an allocated buffer pointed
+  ** to by zPathname, length nPathname. Or, if this is a temporary file,
+  ** leave both nPathname and zPathname set to 0.
+  */
+  if( zFilename && zFilename[0] ){
+    const char *z;
+    nPathname = pVfs->mxPathname+1;
+    zPathname = sqlite3DbMallocRaw(0, nPathname*2);
+    if( zPathname==0 ){
+      return SQLITE_NOMEM;
+    }
+    zPathname[0] = 0; /* Make sure initialized even if FullPathname() fails */
+    rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
+    nPathname = sqlite3Strlen30(zPathname);
+    z = zUri = &zFilename[sqlite3Strlen30(zFilename)+1];
+    while( *z ){
+      z += sqlite3Strlen30(z)+1;
+      z += sqlite3Strlen30(z)+1;
+    }
+    nUri = (int)(&z[1] - zUri);
+    assert( nUri>=0 );
+    if( rc==SQLITE_OK && nPathname+8>pVfs->mxPathname ){
+      /* This branch is taken when the journal path required by
+      ** the database being opened will be more than pVfs->mxPathname
+      ** bytes in length. This means the database cannot be opened,
+      ** as it will not be possible to open the journal file or even
+      ** check for a hot-journal before reading.
+      */
+      rc = SQLITE_CANTOPEN_BKPT;
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3DbFree(0, zPathname);
+      return rc;
+    }
+  }
+
+  /* Allocate memory for the Pager structure, PCache object, the
+  ** three file descriptors, the database file name and the journal 
+  ** file name. The layout in memory is as follows:
+  **
+  **     Pager object                    (sizeof(Pager) bytes)
+  **     PCache object                   (sqlite3PcacheSize() bytes)
+  **     Database file handle            (pVfs->szOsFile bytes)
+  **     Sub-journal file handle         (journalFileSize bytes)
+  **     Main journal file handle        (journalFileSize bytes)
+  **     Database file name              (nPathname+1 bytes)
+  **     Journal file name               (nPathname+8+1 bytes)
+  */
+  pPtr = (u8 *)sqlite3MallocZero(
+    ROUND8(sizeof(*pPager)) +      /* Pager structure */
+    ROUND8(pcacheSize) +           /* PCache object */
+    ROUND8(pVfs->szOsFile) +       /* The main db file */
+    journalFileSize * 2 +          /* The two journal files */ 
+    nPathname + 1 + nUri +         /* zFilename */
+    nPathname + 8 + 2              /* zJournal */
+#ifndef SQLITE_OMIT_WAL
+    + nPathname + 4 + 2            /* zWal */
+#endif
+  );
+  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
+  if( !pPtr ){
+    sqlite3DbFree(0, zPathname);
+    return SQLITE_NOMEM;
+  }
+  pPager =              (Pager*)(pPtr);
+  pPager->pPCache =    (PCache*)(pPtr += ROUND8(sizeof(*pPager)));
+  pPager->fd =   (sqlite3_file*)(pPtr += ROUND8(pcacheSize));
+  pPager->sjfd = (sqlite3_file*)(pPtr += ROUND8(pVfs->szOsFile));
+  pPager->jfd =  (sqlite3_file*)(pPtr += journalFileSize);
+  pPager->zFilename =    (char*)(pPtr += journalFileSize);
+  assert( EIGHT_BYTE_ALIGNMENT(pPager->jfd) );
+
+  /* Fill in the Pager.zFilename and Pager.zJournal buffers, if required. */
+  if( zPathname ){
+    assert( nPathname>0 );
+    pPager->zJournal =   (char*)(pPtr += nPathname + 1 + nUri);
+    memcpy(pPager->zFilename, zPathname, nPathname);
+    if( nUri ) memcpy(&pPager->zFilename[nPathname+1], zUri, nUri);
+    memcpy(pPager->zJournal, zPathname, nPathname);
+    memcpy(&pPager->zJournal[nPathname], "-journal\000", 8+1);
+    sqlite3FileSuffix3(pPager->zFilename, pPager->zJournal);
+#ifndef SQLITE_OMIT_WAL
+    pPager->zWal = &pPager->zJournal[nPathname+8+1];
+    memcpy(pPager->zWal, zPathname, nPathname);
+    memcpy(&pPager->zWal[nPathname], "-wal\000", 4+1);
+    sqlite3FileSuffix3(pPager->zFilename, pPager->zWal);
+#endif
+    sqlite3DbFree(0, zPathname);
+  }
+  pPager->pVfs = pVfs;
+  pPager->vfsFlags = vfsFlags;
+
+  /* Open the pager file.
+  */
+  if( zFilename && zFilename[0] ){
+    int fout = 0;                    /* VFS flags returned by xOpen() */
+    rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, vfsFlags, &fout);
+    assert( !memDb );
+    readOnly = (fout&SQLITE_OPEN_READONLY);
+
+    /* If the file was successfully opened for read/write access,
+    ** choose a default page size in case we have to create the
+    ** database file. The default page size is the maximum of:
+    **
+    **    + SQLITE_DEFAULT_PAGE_SIZE,
+    **    + The value returned by sqlite3OsSectorSize()
+    **    + The largest page size that can be written atomically.
+    */
+    if( rc==SQLITE_OK && !readOnly ){
+      setSectorSize(pPager);
+      assert(SQLITE_DEFAULT_PAGE_SIZE<=SQLITE_MAX_DEFAULT_PAGE_SIZE);
+      if( szPageDflt<pPager->sectorSize ){
+        if( pPager->sectorSize>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
+          szPageDflt = SQLITE_MAX_DEFAULT_PAGE_SIZE;
+        }else{
+          szPageDflt = (u32)pPager->sectorSize;
+        }
+      }
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+      {
+        int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+        int ii;
+        assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+        assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+        assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
+        for(ii=szPageDflt; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
+          if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ){
+            szPageDflt = ii;
+          }
+        }
+      }
+#endif
+    }
+  }else{
+    /* If a temporary file is requested, it is not opened immediately.
+    ** In this case we accept the default page size and delay actually
+    ** opening the file until the first call to OsWrite().
+    **
+    ** This branch is also run for an in-memory database. An in-memory
+    ** database is the same as a temp-file that is never written out to
+    ** disk and uses an in-memory rollback journal.
+    */ 
+    tempFile = 1;
+    pPager->eState = PAGER_READER;
+    pPager->eLock = EXCLUSIVE_LOCK;
+    readOnly = (vfsFlags&SQLITE_OPEN_READONLY);
+  }
+
+  /* The following call to PagerSetPagesize() serves to set the value of 
+  ** Pager.pageSize and to allocate the Pager.pTmpSpace buffer.
+  */
+  if( rc==SQLITE_OK ){
+    assert( pPager->memDb==0 );
+    rc = sqlite3PagerSetPagesize(pPager, &szPageDflt, -1);
+    testcase( rc!=SQLITE_OK );
+  }
+
+  /* If an error occurred in either of the blocks above, free the 
+  ** Pager structure and close the file.
+  */
+  if( rc!=SQLITE_OK ){
+    assert( !pPager->pTmpSpace );
+    sqlite3OsClose(pPager->fd);
+    sqlite3_free(pPager);
+    return rc;
+  }
+
+  /* Initialize the PCache object. */
+  assert( nExtra<1000 );
+  nExtra = ROUND8(nExtra);
+  sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
+                    !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
+
+  PAGERTRACE(("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename));
+  IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))
+
+  pPager->useJournal = (u8)useJournal;
+  /* pPager->stmtOpen = 0; */
+  /* pPager->stmtInUse = 0; */
+  /* pPager->nRef = 0; */
+  /* pPager->stmtSize = 0; */
+  /* pPager->stmtJSize = 0; */
+  /* pPager->nPage = 0; */
+  pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
+  /* pPager->state = PAGER_UNLOCK; */
+#if 0
+  assert( pPager->state == (tempFile ? PAGER_EXCLUSIVE : PAGER_UNLOCK) );
+#endif
+  /* pPager->errMask = 0; */
+  pPager->tempFile = (u8)tempFile;
+  assert( tempFile==PAGER_LOCKINGMODE_NORMAL 
+          || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
+  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
+  pPager->exclusiveMode = (u8)tempFile; 
+  pPager->changeCountDone = pPager->tempFile;
+  pPager->memDb = (u8)memDb;
+  pPager->readOnly = (u8)readOnly;
+  assert( useJournal || pPager->tempFile );
+  pPager->noSync = pPager->tempFile;
+  if( pPager->noSync ){
+    assert( pPager->fullSync==0 );
+    assert( pPager->syncFlags==0 );
+    assert( pPager->walSyncFlags==0 );
+    assert( pPager->ckptSyncFlags==0 );
+  }else{
+    pPager->fullSync = 1;
+    pPager->syncFlags = SQLITE_SYNC_NORMAL;
+    pPager->walSyncFlags = SQLITE_SYNC_NORMAL | WAL_SYNC_TRANSACTIONS;
+    pPager->ckptSyncFlags = SQLITE_SYNC_NORMAL;
+  }
+  /* pPager->pFirst = 0; */
+  /* pPager->pFirstSynced = 0; */
+  /* pPager->pLast = 0; */
+  pPager->nExtra = (u16)nExtra;
+  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
+  assert( isOpen(pPager->fd) || tempFile );
+  setSectorSize(pPager);
+  if( !useJournal ){
+    pPager->journalMode = PAGER_JOURNALMODE_OFF;
+  }else if( memDb ){
+    pPager->journalMode = PAGER_JOURNALMODE_MEMORY;
+  }
+  /* pPager->xBusyHandler = 0; */
+  /* pPager->pBusyHandlerArg = 0; */
+  pPager->xReiniter = xReinit;
+  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
+
+  *ppPager = pPager;
+  return SQLITE_OK;
+}
+
+
+
+/*
+** This function is called after transitioning from PAGER_UNLOCK to
+** PAGER_SHARED state. It tests if there is a hot journal present in
+** the file-system for the given pager. A hot journal is one that 
+** needs to be played back. According to this function, a hot-journal
+** file exists if the following criteria are met:
+**
+**   * The journal file exists in the file system, and
+**   * No process holds a RESERVED or greater lock on the database file, and
+**   * The database file itself is greater than 0 bytes in size, and
+**   * The first byte of the journal file exists and is not 0x00.
 **
 ** If the current size of the database file is 0 but a journal file
 ** exists, that is probably an old journal left over from a prior
-** database with the same name.  Just delete the journal.
+** database with the same name. In this case the journal file is
+** just deleted using OsDelete, *pExists is set to 0 and SQLITE_OK
+** is returned.
 **
-** Return negative if unable to determine the status of the journal.
+** This routine does not check if there is a master journal filename
+** at the end of the file. If there is, and that master journal file
+** does not exist, then the journal file is not really hot. In this
+** case this routine will return a false-positive. The pager_playback()
+** routine will discover that the journal file is not really hot and 
+** will not roll it back. 
 **
-** This routine does not open the journal file to examine its
-** content.  Hence, the journal might contain the name of a master
-** journal file that has been deleted, and hence not be hot.  Or
-** the header of the journal might be zeroed out.  This routine
-** does not discover these cases of a non-hot journal - if the
-** journal file exists and is not empty this routine assumes it
-** is hot.  The pager_playback() routine will discover that the
-** journal file is not really hot and will no-op.
+** If a hot-journal file is found to exist, *pExists is set to 1 and 
+** SQLITE_OK returned. If no hot-journal file is present, *pExists is
+** set to 0 and SQLITE_OK returned. If an IO error occurs while trying
+** to determine whether or not a hot-journal file exists, the IO error
+** code is returned and the value of *pExists is undefined.
 */
 static int hasHotJournal(Pager *pPager, int *pExists){
-  sqlite3_vfs *pVfs = pPager->pVfs;
-  int rc = SQLITE_OK;
-  int exists = 0;
-  int locked = 0;
-  assert( pPager!=0 );
+  sqlite3_vfs * const pVfs = pPager->pVfs;
+  int rc = SQLITE_OK;           /* Return code */
+  int exists = 1;               /* True if a journal file is present */
+  int jrnlOpen = !!isOpen(pPager->jfd);
+
   assert( pPager->useJournal );
-  assert( pPager->fd->pMethods );
+  assert( isOpen(pPager->fd) );
+  assert( pPager->eState==PAGER_OPEN );
+
+  assert( jrnlOpen==0 || ( sqlite3OsDeviceCharacteristics(pPager->jfd) &
+    SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
+  ));
+
   *pExists = 0;
-  rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
+  if( !jrnlOpen ){
+    rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
+  }
   if( rc==SQLITE_OK && exists ){
+    int locked = 0;             /* True if some process holds a RESERVED lock */
+
+    /* Race condition here:  Another process might have been holding the
+    ** the RESERVED lock and have a journal open at the sqlite3OsAccess() 
+    ** call above, but then delete the journal and drop the lock before
+    ** we get to the following sqlite3OsCheckReservedLock() call.  If that
+    ** is the case, this routine might think there is a hot journal when
+    ** in fact there is none.  This results in a false-positive which will
+    ** be dealt with by the playback routine.  Ticket #3883.
+    */
     rc = sqlite3OsCheckReservedLock(pPager->fd, &locked);
-  }
-  if( rc==SQLITE_OK && exists && !locked ){
-    int nPage;
-    rc = sqlite3PagerPagecount(pPager, &nPage);
-    if( rc==SQLITE_OK ){
-     if( nPage==0 ){
-        sqlite3OsDelete(pVfs, pPager->zJournal, 0);
-      }else{
-        *pExists = 1;
+    if( rc==SQLITE_OK && !locked ){
+      Pgno nPage;                 /* Number of pages in database file */
+
+      /* Check the size of the database file. If it consists of 0 pages,
+      ** then delete the journal file. See the header comment above for 
+      ** the reasoning here.  Delete the obsolete journal file under
+      ** a RESERVED lock to avoid race conditions and to avoid violating
+      ** [H33020].
+      */
+      rc = pagerPagecount(pPager, &nPage);
+      if( rc==SQLITE_OK ){
+        if( nPage==0 ){
+          sqlite3BeginBenignMalloc();
+          if( pagerLockDb(pPager, RESERVED_LOCK)==SQLITE_OK ){
+            sqlite3OsDelete(pVfs, pPager->zJournal, 0);
+            if( !pPager->exclusiveMode ) pagerUnlockDb(pPager, SHARED_LOCK);
+          }
+          sqlite3EndBenignMalloc();
+        }else{
+          /* The journal file exists and no other connection has a reserved
+          ** or greater lock on the database file. Now check that there is
+          ** at least one non-zero bytes at the start of the journal file.
+          ** If there is, then we consider this journal to be hot. If not, 
+          ** it can be ignored.
+          */
+          if( !jrnlOpen ){
+            int f = SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL;
+            rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &f);
+          }
+          if( rc==SQLITE_OK ){
+            u8 first = 0;
+            rc = sqlite3OsRead(pPager->jfd, (void *)&first, 1, 0);
+            if( rc==SQLITE_IOERR_SHORT_READ ){
+              rc = SQLITE_OK;
+            }
+            if( !jrnlOpen ){
+              sqlite3OsClose(pPager->jfd);
+            }
+            *pExists = (first!=0);
+          }else if( rc==SQLITE_CANTOPEN ){
+            /* If we cannot open the rollback journal file in order to see if
+            ** its has a zero header, that might be due to an I/O error, or
+            ** it might be due to the race condition described above and in
+            ** ticket #3883.  Either way, assume that the journal is hot.
+            ** This might be a false positive.  But if it is, then the
+            ** automatic journal playback and recovery mechanism will deal
+            ** with it under an EXCLUSIVE lock where we do not need to
+            ** worry so much with race conditions.
+            */
+            *pExists = 1;
+            rc = SQLITE_OK;
+          }
+        }
       }
     }
   }
+
   return rc;
 }
 
 /*
-** Read the content of page pPg out of the database file.
-*/
-static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
-  int rc;
-  i64 offset;
-  assert( MEMDB==0 );
-  assert(pPager->fd->pMethods||pPager->tempFile);
-  if( !pPager->fd->pMethods ){
-    return SQLITE_IOERR_SHORT_READ;
-  }
-  offset = (pgno-1)*(i64)pPager->pageSize;
-  rc = sqlite3OsRead(pPager->fd, pPg->pData, pPager->pageSize, offset);
-  PAGER_INCR(sqlite3_pager_readdb_count);
-  PAGER_INCR(pPager->nRead);
-  IOTRACE(("PGIN %p %d\n", pPager, pgno));
-  if( pgno==1 ){
-    memcpy(&pPager->dbFileVers, &((u8*)pPg->pData)[24],
-                                              sizeof(pPager->dbFileVers));
-  }
-  CODEC1(pPager, pPg->pData, pPg->pgno, 3);
-  PAGERTRACE(("FETCH %d page %d hash(%08x)\n",
-               PAGERID(pPager), pPg->pgno, pager_pagehash(pPg)));
-  return rc;
-}
-
-
-/*
-** This function is called to obtain the shared lock required before
-** data may be read from the pager cache. If the shared lock has already
-** been obtained, this function is a no-op.
+** This function is called to obtain a shared lock on the database file.
+** It is illegal to call sqlite3PagerAcquire() until after this function
+** has been successfully called. If a shared-lock is already held when
+** this function is called, it is a no-op.
 **
-** Immediately after obtaining the shared lock (if required), this function
-** checks for a hot-journal file. If one is found, an emergency rollback
-** is performed immediately.
+** The following operations are also performed by this function.
+**
+**   1) If the pager is currently in PAGER_OPEN state (no lock held
+**      on the database file), then an attempt is made to obtain a
+**      SHARED lock on the database file. Immediately after obtaining
+**      the SHARED lock, the file-system is checked for a hot-journal,
+**      which is played back if present. Following any hot-journal 
+**      rollback, the contents of the cache are validated by checking
+**      the 'change-counter' field of the database file header and
+**      discarded if they are found to be invalid.
+**
+**   2) If the pager is running in exclusive-mode, and there are currently
+**      no outstanding references to any pages, and is in the error state,
+**      then an attempt is made to clear the error state by discarding
+**      the contents of the page cache and rolling back any open journal
+**      file.
+**
+** If everything is successful, SQLITE_OK is returned. If an IO error 
+** occurs while locking the database, checking for a hot-journal file or 
+** rolling back a journal file, the IO error code is returned.
 */
-static int pagerSharedLock(Pager *pPager){
-  int rc = SQLITE_OK;
-  int isErrorReset = 0;
+SQLITE_PRIVATE int sqlite3PagerSharedLock(Pager *pPager){
+  int rc = SQLITE_OK;                /* Return code */
 
-  /* If this database is opened for exclusive access, has no outstanding 
-  ** page references and is in an error-state, now is the chance to clear
-  ** the error. Discard the contents of the pager-cache and treat any
-  ** open journal file as a hot-journal.
+  /* This routine is only called from b-tree and only when there are no
+  ** outstanding pages. This implies that the pager state should either
+  ** be OPEN or READER. READER is only possible if the pager is or was in 
+  ** exclusive access mode.
   */
-  if( !MEMDB && pPager->exclusiveMode 
-   && sqlite3PcacheRefCount(pPager->pPCache)==0 && pPager->errCode 
-  ){
-    if( pPager->journalOpen ){
-      isErrorReset = 1;
-    }
-    pPager->errCode = SQLITE_OK;
-    pager_reset(pPager);
-  }
+  assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
+  if( NEVER(MEMDB && pPager->errCode) ){ return pPager->errCode; }
 
-  /* If the pager is still in an error state, do not proceed. The error 
-  ** state will be cleared at some point in the future when all page 
-  ** references are dropped and the cache can be discarded.
-  */
-  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
-    return pPager->errCode;
-  }
+  if( !pagerUseWal(pPager) && pPager->eState==PAGER_OPEN ){
+    int bHotJournal = 1;          /* True if there exists a hot journal-file */
 
-  if( pPager->state==PAGER_UNLOCK || isErrorReset ){
-    sqlite3_vfs *pVfs = pPager->pVfs;
-    int isHotJournal = 0;
     assert( !MEMDB );
-    assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
-    if( !pPager->noReadlock ){
-      rc = pager_wait_on_lock(pPager, SHARED_LOCK);
-      if( rc!=SQLITE_OK ){
-        assert( pPager->state==PAGER_UNLOCK );
-        return pager_error(pPager, rc);
-      }
-    }else if( pPager->state==PAGER_UNLOCK ){
-      pPager->state = PAGER_SHARED;
+
+    rc = pager_wait_on_lock(pPager, SHARED_LOCK);
+    if( rc!=SQLITE_OK ){
+      assert( pPager->eLock==NO_LOCK || pPager->eLock==UNKNOWN_LOCK );
+      goto failed;
     }
-    assert( pPager->state>=SHARED_LOCK );
 
     /* If a journal file exists, and there is no RESERVED lock on the
     ** database file, then it either needs to be played back or deleted.
     */
-    if( !isErrorReset ){
-      rc = hasHotJournal(pPager, &isHotJournal);
-      if( rc!=SQLITE_OK ){
-        goto failed;
-      }
+    if( pPager->eLock<=SHARED_LOCK ){
+      rc = hasHotJournal(pPager, &bHotJournal);
     }
-    if( isErrorReset || isHotJournal ){
+    if( rc!=SQLITE_OK ){
+      goto failed;
+    }
+    if( bHotJournal ){
       /* Get an EXCLUSIVE lock on the database file. At this point it is
       ** important that a RESERVED lock is not obtained on the way to the
       ** EXCLUSIVE lock. If it were, another process might open the
       ** database file, detect the RESERVED lock, and conclude that the
-      ** database is safe to read while this process is still rolling it 
-      ** back.
+      ** database is safe to read while this process is still rolling the 
+      ** hot-journal back.
       ** 
-      ** Because the intermediate RESERVED lock is not requested, the
-      ** second process will get to this point in the code and fail to
-      ** obtain its own EXCLUSIVE lock on the database file.
+      ** Because the intermediate RESERVED lock is not requested, any
+      ** other process attempting to access the database file will get to 
+      ** this point in the code and fail to obtain its own EXCLUSIVE lock 
+      ** on the database file.
+      **
+      ** Unless the pager is in locking_mode=exclusive mode, the lock is
+      ** downgraded to SHARED_LOCK before this function returns.
       */
-      if( pPager->state<EXCLUSIVE_LOCK ){
-        rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
-        if( rc!=SQLITE_OK ){
-          rc = pager_error(pPager, rc);
-          goto failed;
-        }
-        pPager->state = PAGER_EXCLUSIVE;
-      }
- 
-      /* Open the journal for read/write access. This is because in 
-      ** exclusive-access mode the file descriptor will be kept open and
-      ** possibly used for a transaction later on. On some systems, the
-      ** OsTruncate() call used in exclusive-access mode also requires
-      ** a read/write file handle.
-      */
-      if( !isErrorReset && pPager->journalOpen==0 ){
-        int res;
-        rc = sqlite3OsAccess(pVfs,pPager->zJournal,SQLITE_ACCESS_EXISTS,&res);
-        if( rc==SQLITE_OK ){
-          if( res ){
-            int fout = 0;
-            int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
-            assert( !pPager->tempFile );
-            rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
-            assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
-            if( rc==SQLITE_OK && fout&SQLITE_OPEN_READONLY ){
-              rc = SQLITE_CANTOPEN;
-              sqlite3OsClose(pPager->jfd);
-            }
-          }else{
-            /* If the journal does not exist, that means some other process
-            ** has already rolled it back */
-            rc = SQLITE_BUSY;
-          }
-        }
-      }
+      rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
       if( rc!=SQLITE_OK ){
         goto failed;
       }
-      pPager->journalOpen = 1;
-      pPager->journalStarted = 0;
-      pPager->journalOff = 0;
-      pPager->setMaster = 0;
-      pPager->journalHdr = 0;
+ 
+      /* If it is not already open and the file exists on disk, open the 
+      ** journal for read/write access. Write access is required because 
+      ** in exclusive-access mode the file descriptor will be kept open 
+      ** and possibly used for a transaction later on. Also, write-access 
+      ** is usually required to finalize the journal in journal_mode=persist 
+      ** mode (and also for journal_mode=truncate on some systems).
+      **
+      ** If the journal does not exist, it usually means that some 
+      ** other connection managed to get in and roll it back before 
+      ** this connection obtained the exclusive lock above. Or, it 
+      ** may mean that the pager was in the error-state when this
+      ** function was called and the journal file does not exist.
+      */
+      if( !isOpen(pPager->jfd) ){
+        sqlite3_vfs * const pVfs = pPager->pVfs;
+        int bExists;              /* True if journal file exists */
+        rc = sqlite3OsAccess(
+            pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &bExists);
+        if( rc==SQLITE_OK && bExists ){
+          int fout = 0;
+          int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
+          assert( !pPager->tempFile );
+          rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
+          assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
+          if( rc==SQLITE_OK && fout&SQLITE_OPEN_READONLY ){
+            rc = SQLITE_CANTOPEN_BKPT;
+            sqlite3OsClose(pPager->jfd);
+          }
+        }
+      }
  
       /* Playback and delete the journal.  Drop the database write
       ** lock and reacquire the read lock. Purge the cache before
       ** playing back the hot-journal so that we don't end up with
-      ** an inconsistent cache.
+      ** an inconsistent cache.  Sync the hot journal before playing
+      ** it back since the process that crashed and left the hot journal
+      ** probably did not sync it and we are required to always sync
+      ** the journal before playing it back.
       */
-      sqlite3PcacheClear(pPager->pPCache);
-      rc = pager_playback(pPager, 1);
+      if( isOpen(pPager->jfd) ){
+        assert( rc==SQLITE_OK );
+        rc = pagerSyncHotJournal(pPager);
+        if( rc==SQLITE_OK ){
+          rc = pager_playback(pPager, 1);
+          pPager->eState = PAGER_OPEN;
+        }
+      }else if( !pPager->exclusiveMode ){
+        pagerUnlockDb(pPager, SHARED_LOCK);
+      }
+
       if( rc!=SQLITE_OK ){
-        rc = pager_error(pPager, rc);
+        /* This branch is taken if an error occurs while trying to open
+        ** or roll back a hot-journal while holding an EXCLUSIVE lock. The
+        ** pager_unlock() routine will be called before returning to unlock
+        ** the file. If the unlock attempt fails, then Pager.eLock must be
+        ** set to UNKNOWN_LOCK (see the comment above the #define for 
+        ** UNKNOWN_LOCK above for an explanation). 
+        **
+        ** In order to get pager_unlock() to do this, set Pager.eState to
+        ** PAGER_ERROR now. This is not actually counted as a transition
+        ** to ERROR state in the state diagram at the top of this file,
+        ** since we know that the same call to pager_unlock() will very
+        ** shortly transition the pager object to the OPEN state. Calling
+        ** assert_pager_state() would fail now, as it should not be possible
+        ** to be in ERROR state when there are zero outstanding page 
+        ** references.
+        */
+        pager_error(pPager, rc);
         goto failed;
       }
-      assert(pPager->state==PAGER_SHARED || 
-          (pPager->exclusiveMode && pPager->state>PAGER_SHARED)
+
+      assert( pPager->eState==PAGER_OPEN );
+      assert( (pPager->eLock==SHARED_LOCK)
+           || (pPager->exclusiveMode && pPager->eLock>SHARED_LOCK)
       );
     }
 
-    if( sqlite3PcachePagecount(pPager->pPCache)>0 ){
+    if( !pPager->tempFile 
+     && (pPager->pBackup || sqlite3PcachePagecount(pPager->pPCache)>0) 
+    ){
       /* The shared-lock has just been acquired on the database file
       ** and there are already pages in the cache (from a previous
       ** read or write transaction).  Check to see if the database
@@ -33733,16 +41849,13 @@ static int pagerSharedLock(Pager *pPager){
       ** detected.  The chance of an undetected change is so small that
       ** it can be neglected.
       */
+      Pgno nPage = 0;
       char dbFileVers[sizeof(pPager->dbFileVers)];
-      sqlite3PagerPagecount(pPager, 0);
 
-      if( pPager->errCode ){
-        rc = pPager->errCode;
-        goto failed;
-      }
+      rc = pagerPagecount(pPager, &nPage);
+      if( rc ) goto failed;
 
-      assert( pPager->dbSizeValid );
-      if( pPager->dbSize>0 ){
+      if( nPage>0 ){
         IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
         rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
         if( rc!=SQLITE_OK ){
@@ -33756,71 +41869,88 @@ static int pagerSharedLock(Pager *pPager){
         pager_reset(pPager);
       }
     }
-    assert( pPager->exclusiveMode || pPager->state==PAGER_SHARED );
+
+    /* If there is a WAL file in the file-system, open this database in WAL
+    ** mode. Otherwise, the following function call is a no-op.
+    */
+    rc = pagerOpenWalIfPresent(pPager);
+#ifndef SQLITE_OMIT_WAL
+    assert( pPager->pWal==0 || rc==SQLITE_OK );
+#endif
+  }
+
+  if( pagerUseWal(pPager) ){
+    assert( rc==SQLITE_OK );
+    rc = pagerBeginReadTransaction(pPager);
+  }
+
+  if( pPager->eState==PAGER_OPEN && rc==SQLITE_OK ){
+    rc = pagerPagecount(pPager, &pPager->dbSize);
   }
 
  failed:
   if( rc!=SQLITE_OK ){
-    /* pager_unlock() is a no-op for exclusive mode and in-memory databases. */
+    assert( !MEMDB );
     pager_unlock(pPager);
+    assert( pPager->eState==PAGER_OPEN );
+  }else{
+    pPager->eState = PAGER_READER;
   }
   return rc;
 }
 
 /*
-** Make sure we have the content for a page.  If the page was
-** previously acquired with noContent==1, then the content was
-** just initialized to zeros instead of being read from disk.
-** But now we need the real data off of disk.  So make sure we
-** have it.  Read it in if we do not have it already.
-*/
-static int pager_get_content(PgHdr *pPg){
-  if( pPg->flags&PGHDR_NEED_READ ){
-    int rc = readDbPage(pPg->pPager, pPg, pPg->pgno);
-    if( rc==SQLITE_OK ){
-      pPg->flags &= ~PGHDR_NEED_READ;
-    }else{
-      return rc;
-    }
-  }
-  return SQLITE_OK;
-}
-
-/*
-** If the reference count has reached zero, and the pager is not in the
-** middle of a write transaction or opened in exclusive mode, unlock it.
+** If the reference count has reached zero, rollback any active
+** transaction and unlock the pager.
+**
+** Except, in locking_mode=EXCLUSIVE when there is nothing to in
+** the rollback journal, the unlock is not performed and there is
+** nothing to rollback, so this routine is a no-op.
 */ 
 static void pagerUnlockIfUnused(Pager *pPager){
-  if( (sqlite3PcacheRefCount(pPager->pPCache)==0)
-    && (!pPager->exclusiveMode || pPager->journalOff>0) 
-  ){
+  if( (sqlite3PcacheRefCount(pPager->pPCache)==0) ){
     pagerUnlockAndRollback(pPager);
   }
 }
 
 /*
-** Drop a page from the cache using sqlite3PcacheDrop().
+** Acquire a reference to page number pgno in pager pPager (a page
+** reference has type DbPage*). If the requested reference is 
+** successfully obtained, it is copied to *ppPage and SQLITE_OK returned.
 **
-** If this means there are now no pages with references to them, a rollback
-** occurs and the lock on the database is removed.
-*/
-static void pagerDropPage(DbPage *pPg){
-  Pager *pPager = pPg->pPager;
-  sqlite3PcacheDrop(pPg);
-  pagerUnlockIfUnused(pPager);
-}
-
-/*
-** Acquire a page.
+** If the requested page is already in the cache, it is returned. 
+** Otherwise, a new page object is allocated and populated with data
+** read from the database file. In some cases, the pcache module may
+** choose not to allocate a new page object and may reuse an existing
+** object with no outstanding references.
 **
-** A read lock on the disk file is obtained when the first page is acquired. 
-** This read lock is dropped when the last page is released.
+** The extra data appended to a page is always initialized to zeros the 
+** first time a page is loaded into memory. If the page requested is 
+** already in the cache when this function is called, then the extra
+** data is left as it was when the page object was last used.
 **
-** This routine works for any page number greater than 0.  If the database
-** file is smaller than the requested page, then no actual disk
-** read occurs and the memory image of the page is initialized to
-** all zeros.  The extra data appended to a page is always initialized
-** to zeros the first time a page is loaded into memory.
+** If the database image is smaller than the requested page or if a 
+** non-zero value is passed as the noContent parameter and the 
+** requested page is not already stored in the cache, then no 
+** actual disk read occurs. In this case the memory image of the 
+** page is initialized to all zeros. 
+**
+** If noContent is true, it means that we do not care about the contents
+** of the page. This occurs in two seperate scenarios:
+**
+**   a) When reading a free-list leaf page from the database, and
+**
+**   b) When a savepoint is being rolled back and we need to load
+**      a new page into the cache to be filled with the data read
+**      from the savepoint journal.
+**
+** If noContent is true, then the data returned is zeroed instead of
+** being read from the database. Additionally, the bits corresponding
+** to pgno in Pager.pInJournal (bitvec of pages already written to the
+** journal file) and the PagerSavepoint.pInSavepoint bitvecs of any open
+** savepoints are set. This means if the page is made writable at any
+** point in the future, using a call to sqlite3PagerWrite(), its contents
+** will not be journaled. This saves IO.
 **
 ** The acquisition might fail for several reasons.  In all cases,
 ** an appropriate error code is returned and *ppPage is set to NULL.
@@ -33832,15 +41962,6 @@ static void pagerDropPage(DbPage *pPg){
 ** has to go to disk, and could also playback an old journal if necessary.
 ** Since Lookup() never goes to disk, it never has to deal with locks
 ** or journal files.
-**
-** If noContent is false, the page contents are actually read from disk.
-** If noContent is true, it means that we do not care about the contents
-** of the page at this time, so do not do a disk read.  Just fill in the
-** page content with zeros.  But mark the fact that we have not read the
-** content by setting the PgHdr.needRead flag.  Later on, if 
-** sqlite3PagerWrite() is called on this page or if this routine is
-** called again with noContent==0, that means that the content is needed
-** and the disk read should occur at that point.
 */
 SQLITE_PRIVATE int sqlite3PagerAcquire(
   Pager *pPager,      /* The pager open on the database file */
@@ -33848,97 +41969,106 @@ SQLITE_PRIVATE int sqlite3PagerAcquire(
   DbPage **ppPage,    /* Write a pointer to the page here */
   int noContent       /* Do not bother reading content from disk if true */
 ){
-  PgHdr *pPg = 0;
   int rc;
+  PgHdr *pPg;
 
-  assert( pPager->state==PAGER_UNLOCK 
-       || sqlite3PcacheRefCount(pPager->pPCache)>0 
-       || pgno==1
-  );
+  assert( pPager->eState>=PAGER_READER );
+  assert( assert_pager_state(pPager) );
 
-  /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
-  ** number greater than this, or zero, is requested.
-  */
-  if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
+  if( pgno==0 ){
     return SQLITE_CORRUPT_BKPT;
   }
 
-  /* Make sure we have not hit any critical errors.
-  */ 
-  assert( pPager!=0 );
-  *ppPage = 0;
-
-  /* If this is the first page accessed, then get a SHARED lock
-  ** on the database file. pagerSharedLock() is a no-op if 
-  ** a database lock is already held.
-  */
-  rc = pagerSharedLock(pPager);
-  if( rc!=SQLITE_OK ){
-    return rc;
+  /* If the pager is in the error state, return an error immediately. 
+  ** Otherwise, request the page from the PCache layer. */
+  if( pPager->errCode!=SQLITE_OK ){
+    rc = pPager->errCode;
+  }else{
+    rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 1, ppPage);
   }
-  assert( pPager->state!=PAGER_UNLOCK );
 
-  rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 1, &pPg);
   if( rc!=SQLITE_OK ){
-    return rc;
+    /* Either the call to sqlite3PcacheFetch() returned an error or the
+    ** pager was already in the error-state when this function was called.
+    ** Set pPg to 0 and jump to the exception handler.  */
+    pPg = 0;
+    goto pager_acquire_err;
   }
-  if( pPg->pPager==0 ){
+  assert( (*ppPage)->pgno==pgno );
+  assert( (*ppPage)->pPager==pPager || (*ppPage)->pPager==0 );
+
+  if( (*ppPage)->pPager && !noContent ){
+    /* In this case the pcache already contains an initialized copy of
+    ** the page. Return without further ado.  */
+    assert( pgno<=PAGER_MAX_PGNO && pgno!=PAGER_MJ_PGNO(pPager) );
+    pPager->aStat[PAGER_STAT_HIT]++;
+    return SQLITE_OK;
+
+  }else{
     /* The pager cache has created a new page. Its content needs to 
-    ** be initialized.
-    */
-    int nMax;
-    PAGER_INCR(pPager->nMiss);
-    pPg->pPager = pPager;
-    memset(pPg->pExtra, 0, pPager->nExtra);
+    ** be initialized.  */
 
-    rc = sqlite3PagerPagecount(pPager, &nMax);
-    if( rc!=SQLITE_OK ){
-      sqlite3PagerUnref(pPg);
-      return rc;
+    pPg = *ppPage;
+    pPg->pPager = pPager;
+
+    /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
+    ** number greater than this, or the unused locking-page, is requested. */
+    if( pgno>PAGER_MAX_PGNO || pgno==PAGER_MJ_PGNO(pPager) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto pager_acquire_err;
     }
 
-    if( nMax<(int)pgno || MEMDB || noContent ){
+    if( MEMDB || pPager->dbSize<pgno || noContent || !isOpen(pPager->fd) ){
       if( pgno>pPager->mxPgno ){
-        sqlite3PagerUnref(pPg);
-        return SQLITE_FULL;
+        rc = SQLITE_FULL;
+        goto pager_acquire_err;
+      }
+      if( noContent ){
+        /* Failure to set the bits in the InJournal bit-vectors is benign.
+        ** It merely means that we might do some extra work to journal a 
+        ** page that does not need to be journaled.  Nevertheless, be sure 
+        ** to test the case where a malloc error occurs while trying to set 
+        ** a bit in a bit vector.
+        */
+        sqlite3BeginBenignMalloc();
+        if( pgno<=pPager->dbOrigSize ){
+          TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pgno);
+          testcase( rc==SQLITE_NOMEM );
+        }
+        TESTONLY( rc = ) addToSavepointBitvecs(pPager, pgno);
+        testcase( rc==SQLITE_NOMEM );
+        sqlite3EndBenignMalloc();
       }
       memset(pPg->pData, 0, pPager->pageSize);
-      if( noContent ){
-        pPg->flags |= PGHDR_NEED_READ;
-      }
       IOTRACE(("ZERO %p %d\n", pPager, pgno));
     }else{
-      rc = readDbPage(pPager, pPg, pgno);
-      if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
-        /* sqlite3PagerUnref(pPg); */
-        pagerDropPage(pPg);
-        return rc;
-      }
-    }
-#ifdef SQLITE_CHECK_PAGES
-    pPg->pageHash = pager_pagehash(pPg);
-#endif
-  }else{
-    /* The requested page is in the page cache. */
-    assert(sqlite3PcacheRefCount(pPager->pPCache)>0 || pgno==1);
-    PAGER_INCR(pPager->nHit);
-    if( !noContent ){
-      rc = pager_get_content(pPg);
-      if( rc ){
-        sqlite3PagerUnref(pPg);
-        return rc;
+      assert( pPg->pPager==pPager );
+      pPager->aStat[PAGER_STAT_MISS]++;
+      rc = readDbPage(pPg);
+      if( rc!=SQLITE_OK ){
+        goto pager_acquire_err;
       }
     }
+    pager_set_pagehash(pPg);
   }
 
-  *ppPage = pPg;
   return SQLITE_OK;
+
+pager_acquire_err:
+  assert( rc!=SQLITE_OK );
+  if( pPg ){
+    sqlite3PcacheDrop(pPg);
+  }
+  pagerUnlockIfUnused(pPager);
+
+  *ppPage = 0;
+  return rc;
 }
 
 /*
 ** Acquire a page if it is already in the in-memory cache.  Do
 ** not read the page from disk.  Return a pointer to the page,
-** or 0 if the page is not in cache.
+** or 0 if the page is not in cache. 
 **
 ** See also sqlite3PagerGet().  The difference between this routine
 ** and sqlite3PagerGet() is that _get() will go to the disk and read
@@ -33950,311 +42080,291 @@ SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
   PgHdr *pPg = 0;
   assert( pPager!=0 );
   assert( pgno!=0 );
-
-  if( (pPager->state!=PAGER_UNLOCK)
-   && (pPager->errCode==SQLITE_OK || pPager->errCode==SQLITE_FULL)
-  ){
-    sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
-  }
-
+  assert( pPager->pPCache!=0 );
+  assert( pPager->eState>=PAGER_READER && pPager->eState!=PAGER_ERROR );
+  sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
   return pPg;
 }
 
 /*
-** Release a page.
+** Release a page reference.
 **
 ** If the number of references to the page drop to zero, then the
 ** page is added to the LRU list.  When all references to all pages
 ** are released, a rollback occurs and the lock on the database is
 ** removed.
 */
-SQLITE_PRIVATE int sqlite3PagerUnref(DbPage *pPg){
+SQLITE_PRIVATE void sqlite3PagerUnref(DbPage *pPg){
   if( pPg ){
     Pager *pPager = pPg->pPager;
     sqlite3PcacheRelease(pPg);
     pagerUnlockIfUnused(pPager);
   }
-  return SQLITE_OK;
 }
 
 /*
-** If the main journal file has already been opened, ensure that the
-** sub-journal file is open too. If the main journal is not open,
-** this function is a no-op.
+** This function is called at the start of every write transaction.
+** There must already be a RESERVED or EXCLUSIVE lock on the database 
+** file when this routine is called.
 **
-** SQLITE_OK is returned if everything goes according to plan. An 
-** SQLITE_IOERR_XXX error code is returned if the call to 
-** sqlite3OsOpen() fails.
-*/
-static int openSubJournal(Pager *pPager){
-  int rc = SQLITE_OK;
-  if( pPager->journalOpen && !pPager->sjfd->pMethods ){
-    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
-      sqlite3MemJournalOpen(pPager->sjfd);
-    }else{
-      rc = sqlite3PagerOpentemp(pPager, pPager->sjfd, SQLITE_OPEN_SUBJOURNAL);
-    }
-  }
-  return rc;
-}
-
-/*
-** Create a journal file for pPager.  There should already be a RESERVED
-** or EXCLUSIVE lock on the database file when this routine is called.
+** Open the journal file for pager pPager and write a journal header
+** to the start of it. If there are active savepoints, open the sub-journal
+** as well. This function is only used when the journal file is being 
+** opened to write a rollback log for a transaction. It is not used 
+** when opening a hot journal file to roll it back.
 **
-** Return SQLITE_OK if everything.  Return an error code and release the
-** write lock if anything goes wrong.
+** If the journal file is already open (as it may be in exclusive mode),
+** then this function just writes a journal header to the start of the
+** already open file. 
+**
+** Whether or not the journal file is opened by this function, the
+** Pager.pInJournal bitvec structure is allocated.
+**
+** Return SQLITE_OK if everything is successful. Otherwise, return 
+** SQLITE_NOMEM if the attempt to allocate Pager.pInJournal fails, or 
+** an IO error code if opening or writing the journal file fails.
 */
 static int pager_open_journal(Pager *pPager){
-  sqlite3_vfs *pVfs = pPager->pVfs;
-  int flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_CREATE);
+  int rc = SQLITE_OK;                        /* Return code */
+  sqlite3_vfs * const pVfs = pPager->pVfs;   /* Local cache of vfs pointer */
 
-  int rc;
-  assert( pPager->state>=PAGER_RESERVED );
-  assert( pPager->useJournal );
+  assert( pPager->eState==PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
   assert( pPager->pInJournal==0 );
-  sqlite3PagerPagecount(pPager, 0);
-  pPager->pInJournal = sqlite3BitvecCreate(pPager->dbSize);
-  if( pPager->pInJournal==0 ){
-    rc = SQLITE_NOMEM;
-    goto failed_to_open_journal;
-  }
+  
+  /* If already in the error state, this function is a no-op.  But on
+  ** the other hand, this routine is never called if we are already in
+  ** an error state. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
 
-  if( pPager->journalOpen==0 ){
-    if( pPager->tempFile ){
-      flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
-    }else{
-      flags |= (SQLITE_OPEN_MAIN_JOURNAL);
+  if( !pagerUseWal(pPager) && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+    pPager->pInJournal = sqlite3BitvecCreate(pPager->dbSize);
+    if( pPager->pInJournal==0 ){
+      return SQLITE_NOMEM;
     }
-    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
-      sqlite3MemJournalOpen(pPager->jfd);
-      rc = SQLITE_OK;
-    }else{
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
-      rc = sqlite3JournalOpen(
-          pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
-      );
-#else
-      rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
-#endif
-    }
-    assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
-    pPager->journalOff = 0;
-    pPager->setMaster = 0;
-    pPager->journalHdr = 0;
-    if( rc!=SQLITE_OK ){
-      if( rc==SQLITE_NOMEM ){
-        sqlite3OsDelete(pVfs, pPager->zJournal, 0);
+  
+    /* Open the journal file if it is not already open. */
+    if( !isOpen(pPager->jfd) ){
+      if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
+        sqlite3MemJournalOpen(pPager->jfd);
+      }else{
+        const int flags =                   /* VFS flags to open journal file */
+          SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
+          (pPager->tempFile ? 
+            (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL):
+            (SQLITE_OPEN_MAIN_JOURNAL)
+          );
+  #ifdef SQLITE_ENABLE_ATOMIC_WRITE
+        rc = sqlite3JournalOpen(
+            pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
+        );
+  #else
+        rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
+  #endif
       }
-      goto failed_to_open_journal;
+      assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
     }
-  }
-  pPager->journalOpen = 1;
-  pPager->journalStarted = 0;
-  pPager->needSync = 0;
-  pPager->nRec = 0;
-  if( pPager->errCode ){
-    rc = pPager->errCode;
-    goto failed_to_open_journal;
-  }
-  pPager->dbOrigSize = pPager->dbSize;
-
-  rc = writeJournalHdr(pPager);
-
-  if( pPager->nSavepoint && rc==SQLITE_OK ){
-    rc = openSubJournal(pPager);
-  }
-  if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && rc!=SQLITE_IOERR_NOMEM ){
-    rc = pager_end_transaction(pPager, 0);
-    if( rc==SQLITE_OK ){
-      rc = SQLITE_FULL;
-    }
-  }
-  return rc;
-
-failed_to_open_journal:
-  sqlite3BitvecDestroy(pPager->pInJournal);
-  pPager->pInJournal = 0;
-  return rc;
-}
-
-/*
-** Acquire a write-lock on the database.  The lock is removed when
-** the any of the following happen:
-**
-**   *  sqlite3PagerCommitPhaseTwo() is called.
-**   *  sqlite3PagerRollback() is called.
-**   *  sqlite3PagerClose() is called.
-**   *  sqlite3PagerUnref() is called to on every outstanding page.
-**
-** The first parameter to this routine is a pointer to any open page of the
-** database file.  Nothing changes about the page - it is used merely to
-** acquire a pointer to the Pager structure and as proof that there is
-** already a read-lock on the database.
-**
-** The second parameter indicates how much space in bytes to reserve for a
-** master journal file-name at the start of the journal when it is created.
-**
-** A journal file is opened if this is not a temporary file.  For temporary
-** files, the opening of the journal file is deferred until there is an
-** actual need to write to the journal.
-**
-** If the database is already reserved for writing, this routine is a no-op.
-**
-** If exFlag is true, go ahead and get an EXCLUSIVE lock on the file
-** immediately instead of waiting until we try to flush the cache.  The
-** exFlag is ignored if a transaction is already active.
-*/
-SQLITE_PRIVATE int sqlite3PagerBegin(DbPage *pPg, int exFlag){
-  Pager *pPager = pPg->pPager;
-  int rc = SQLITE_OK;
-  assert( pPg->nRef>0 );
-  assert( pPager->state!=PAGER_UNLOCK );
-  if( pPager->state==PAGER_SHARED ){
-    assert( pPager->pInJournal==0 );
-    assert( !MEMDB );
-    rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);
-    if( rc==SQLITE_OK ){
-      pPager->state = PAGER_RESERVED;
-      if( exFlag ){
-        rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
-      }
-    }
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
-    pPager->dirtyCache = 0;
-    PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
-    if( pPager->useJournal && !pPager->tempFile
-           && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
-      rc = pager_open_journal(pPager);
-    }
-  }else if( pPager->journalOpen && pPager->journalOff==0 ){
-    /* This happens when the pager was in exclusive-access mode the last
-    ** time a (read or write) transaction was successfully concluded
-    ** by this connection. Instead of deleting the journal file it was 
-    ** kept open and either was truncated to 0 bytes or its header was
-    ** overwritten with zeros.
+  
+  
+    /* Write the first journal header to the journal file and open 
+    ** the sub-journal if necessary.
     */
-    assert( pPager->nRec==0 );
-    assert( pPager->dbOrigSize==0 );
-    assert( pPager->pInJournal==0 );
-    sqlite3PagerPagecount(pPager, 0);
-    pPager->pInJournal = sqlite3BitvecCreate( pPager->dbSize );
-    if( !pPager->pInJournal ){
-      rc = SQLITE_NOMEM;
-    }else{
-      pPager->dbOrigSize = pPager->dbSize;
+    if( rc==SQLITE_OK ){
+      /* TODO: Check if all of these are really required. */
+      pPager->nRec = 0;
+      pPager->journalOff = 0;
+      pPager->setMaster = 0;
+      pPager->journalHdr = 0;
       rc = writeJournalHdr(pPager);
     }
   }
-  assert( !pPager->journalOpen || pPager->journalOff>0 || rc!=SQLITE_OK );
+
+  if( rc!=SQLITE_OK ){
+    sqlite3BitvecDestroy(pPager->pInJournal);
+    pPager->pInJournal = 0;
+  }else{
+    assert( pPager->eState==PAGER_WRITER_LOCKED );
+    pPager->eState = PAGER_WRITER_CACHEMOD;
+  }
+
   return rc;
 }
 
 /*
-** Mark a data page as writeable.  The page is written into the journal 
-** if it is not there already.  This routine must be called before making
-** changes to a page.
+** Begin a write-transaction on the specified pager object. If a 
+** write-transaction has already been opened, this function is a no-op.
 **
-** The first time this routine is called, the pager creates a new
-** journal and acquires a RESERVED lock on the database.  If the RESERVED
-** lock could not be acquired, this routine returns SQLITE_BUSY.  The
-** calling routine must check for that return value and be careful not to
-** change any page data until this routine returns SQLITE_OK.
+** If the exFlag argument is false, then acquire at least a RESERVED
+** lock on the database file. If exFlag is true, then acquire at least
+** an EXCLUSIVE lock. If such a lock is already held, no locking 
+** functions need be called.
 **
-** If the journal file could not be written because the disk is full,
-** then this routine returns SQLITE_FULL and does an immediate rollback.
-** All subsequent write attempts also return SQLITE_FULL until there
-** is a call to sqlite3PagerCommit() or sqlite3PagerRollback() to
-** reset.
+** If the subjInMemory argument is non-zero, then any sub-journal opened
+** within this transaction will be opened as an in-memory file. This
+** has no effect if the sub-journal is already opened (as it may be when
+** running in exclusive mode) or if the transaction does not require a
+** sub-journal. If the subjInMemory argument is zero, then any required
+** sub-journal is implemented in-memory if pPager is an in-memory database, 
+** or using a temporary file otherwise.
+*/
+SQLITE_PRIVATE int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory){
+  int rc = SQLITE_OK;
+
+  if( pPager->errCode ) return pPager->errCode;
+  assert( pPager->eState>=PAGER_READER && pPager->eState<PAGER_ERROR );
+  pPager->subjInMemory = (u8)subjInMemory;
+
+  if( ALWAYS(pPager->eState==PAGER_READER) ){
+    assert( pPager->pInJournal==0 );
+
+    if( pagerUseWal(pPager) ){
+      /* If the pager is configured to use locking_mode=exclusive, and an
+      ** exclusive lock on the database is not already held, obtain it now.
+      */
+      if( pPager->exclusiveMode && sqlite3WalExclusiveMode(pPager->pWal, -1) ){
+        rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        sqlite3WalExclusiveMode(pPager->pWal, 1);
+      }
+
+      /* Grab the write lock on the log file. If successful, upgrade to
+      ** PAGER_RESERVED state. Otherwise, return an error code to the caller.
+      ** The busy-handler is not invoked if another connection already
+      ** holds the write-lock. If possible, the upper layer will call it.
+      */
+      rc = sqlite3WalBeginWriteTransaction(pPager->pWal);
+    }else{
+      /* Obtain a RESERVED lock on the database file. If the exFlag parameter
+      ** is true, then immediately upgrade this to an EXCLUSIVE lock. The
+      ** busy-handler callback can be used when upgrading to the EXCLUSIVE
+      ** lock, but not when obtaining the RESERVED lock.
+      */
+      rc = pagerLockDb(pPager, RESERVED_LOCK);
+      if( rc==SQLITE_OK && exFlag ){
+        rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      /* Change to WRITER_LOCKED state.
+      **
+      ** WAL mode sets Pager.eState to PAGER_WRITER_LOCKED or CACHEMOD
+      ** when it has an open transaction, but never to DBMOD or FINISHED.
+      ** This is because in those states the code to roll back savepoint 
+      ** transactions may copy data from the sub-journal into the database 
+      ** file as well as into the page cache. Which would be incorrect in 
+      ** WAL mode.
+      */
+      pPager->eState = PAGER_WRITER_LOCKED;
+      pPager->dbHintSize = pPager->dbSize;
+      pPager->dbFileSize = pPager->dbSize;
+      pPager->dbOrigSize = pPager->dbSize;
+      pPager->journalOff = 0;
+    }
+
+    assert( rc==SQLITE_OK || pPager->eState==PAGER_READER );
+    assert( rc!=SQLITE_OK || pPager->eState==PAGER_WRITER_LOCKED );
+    assert( assert_pager_state(pPager) );
+  }
+
+  PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
+  return rc;
+}
+
+/*
+** Mark a single data page as writeable. The page is written into the 
+** main journal or sub-journal as required. If the page is written into
+** one of the journals, the corresponding bit is set in the 
+** Pager.pInJournal bitvec and the PagerSavepoint.pInSavepoint bitvecs
+** of any open savepoints as appropriate.
 */
 static int pager_write(PgHdr *pPg){
   void *pData = pPg->pData;
   Pager *pPager = pPg->pPager;
   int rc = SQLITE_OK;
 
-  /* Check for errors
+  /* This routine is not called unless a write-transaction has already 
+  ** been started. The journal file may or may not be open at this point.
+  ** It is never called in the ERROR state.
   */
-  if( pPager->errCode ){ 
-    return pPager->errCode;
-  }
-  if( pPager->readOnly ){
-    return SQLITE_PERM;
-  }
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
 
-  assert( !pPager->setMaster );
+  /* If an error has been previously detected, report the same error
+  ** again. This should not happen, but the check provides robustness. */
+  if( NEVER(pPager->errCode) )  return pPager->errCode;
+
+  /* Higher-level routines never call this function if database is not
+  ** writable.  But check anyway, just for robustness. */
+  if( NEVER(pPager->readOnly) ) return SQLITE_PERM;
 
   CHECK_PAGE(pPg);
 
-  /* If this page was previously acquired with noContent==1, that means
-  ** we didn't really read in the content of the page.  This can happen
-  ** (for example) when the page is being moved to the freelist.  But
-  ** now we are (perhaps) moving the page off of the freelist for
-  ** reuse and we need to know its original content so that content
-  ** can be stored in the rollback journal.  So do the read at this
-  ** time.
+  /* The journal file needs to be opened. Higher level routines have already
+  ** obtained the necessary locks to begin the write-transaction, but the
+  ** rollback journal might not yet be open. Open it now if this is the case.
+  **
+  ** This is done before calling sqlite3PcacheMakeDirty() on the page. 
+  ** Otherwise, if it were done after calling sqlite3PcacheMakeDirty(), then
+  ** an error might occur and the pager would end up in WRITER_LOCKED state
+  ** with pages marked as dirty in the cache.
   */
-  rc = pager_get_content(pPg);
-  if( rc ){
-    return rc;
+  if( pPager->eState==PAGER_WRITER_LOCKED ){
+    rc = pager_open_journal(pPager);
+    if( rc!=SQLITE_OK ) return rc;
   }
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
+  assert( assert_pager_state(pPager) );
 
   /* Mark the page as dirty.  If the page has already been written
   ** to the journal then we can return right away.
   */
   sqlite3PcacheMakeDirty(pPg);
   if( pageInJournal(pPg) && !subjRequiresPage(pPg) ){
-    pPager->dirtyCache = 1;
-    pPager->dbModified = 1;
+    assert( !pagerUseWal(pPager) );
   }else{
-
-    /* If we get this far, it means that the page needs to be
-    ** written to the transaction journal or the ckeckpoint journal
-    ** or both.
-    **
-    ** First check to see that the transaction journal exists and
-    ** create it if it does not.
-    */
-    assert( pPager->state!=PAGER_UNLOCK );
-    rc = sqlite3PagerBegin(pPg, 0);
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
-    assert( pPager->state>=PAGER_RESERVED );
-    if( !pPager->journalOpen && pPager->useJournal
-          && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
-      rc = pager_open_journal(pPager);
-      if( rc!=SQLITE_OK ) return rc;
-    }
-    pPager->dirtyCache = 1;
-    pPager->dbModified = 1;
   
     /* The transaction journal now exists and we have a RESERVED or an
     ** EXCLUSIVE lock on the main database file.  Write the current page to
     ** the transaction journal if it is not there already.
     */
-    if( !pageInJournal(pPg) && pPager->journalOpen ){
-      if( pPg->pgno<=pPager->dbOrigSize ){
+    if( !pageInJournal(pPg) && !pagerUseWal(pPager) ){
+      assert( pagerUseWal(pPager)==0 );
+      if( pPg->pgno<=pPager->dbOrigSize && isOpen(pPager->jfd) ){
         u32 cksum;
         char *pData2;
+        i64 iOff = pPager->journalOff;
 
         /* We should never write to the journal file the page that
         ** contains the database locks.  The following assert verifies
         ** that we do not. */
         assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
-        pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
+
+        assert( pPager->journalHdr<=pPager->journalOff );
+        CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
         cksum = pager_cksum(pPager, (u8*)pData2);
-        rc = write32bits(pPager->jfd, pPager->journalOff, pPg->pgno);
-        if( rc==SQLITE_OK ){
-          rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize,
-                              pPager->journalOff + 4);
-          pPager->journalOff += pPager->pageSize+4;
-        }
-        if( rc==SQLITE_OK ){
-          rc = write32bits(pPager->jfd, pPager->journalOff, cksum);
-          pPager->journalOff += 4;
-        }
+
+        /* Even if an IO or diskfull error occurs while journalling the
+        ** page in the block above, set the need-sync flag for the page.
+        ** Otherwise, when the transaction is rolled back, the logic in
+        ** playback_one_page() will think that the page needs to be restored
+        ** in the database file. And if an IO error occurs while doing so,
+        ** then corruption may follow.
+        */
+        pPg->flags |= PGHDR_NEED_SYNC;
+
+        rc = write32bits(pPager->jfd, iOff, pPg->pgno);
+        if( rc!=SQLITE_OK ) return rc;
+        rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize, iOff+4);
+        if( rc!=SQLITE_OK ) return rc;
+        rc = write32bits(pPager->jfd, iOff+pPager->pageSize+4, cksum);
+        if( rc!=SQLITE_OK ) return rc;
+
         IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno, 
                  pPager->journalOff, pPager->pageSize));
         PAGER_INCR(sqlite3_pager_writej_count);
@@ -34262,25 +42372,7 @@ static int pager_write(PgHdr *pPg){
              PAGERID(pPager), pPg->pgno, 
              ((pPg->flags&PGHDR_NEED_SYNC)?1:0), pager_pagehash(pPg)));
 
-        /* Even if an IO or diskfull error occurred while journalling the
-        ** page in the block above, set the need-sync flag for the page.
-        ** Otherwise, when the transaction is rolled back, the logic in
-        ** playback_one_page() will think that the page needs to be restored
-        ** in the database file. And if an IO error occurs while doing so,
-        ** then corruption may follow.
-        */
-        if( !pPager->noSync ){
-          pPg->flags |= PGHDR_NEED_SYNC;
-          pPager->needSync = 1;
-        }
-
-        /* An error has occured writing to the journal file. The 
-        ** transaction will be rolled back by the layer above.
-        */
-        if( rc!=SQLITE_OK ){
-          return rc;
-        }
-
+        pPager->journalOff += 8 + pPager->pageSize;
         pPager->nRec++;
         assert( pPager->pInJournal!=0 );
         rc = sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
@@ -34292,9 +42384,8 @@ static int pager_write(PgHdr *pPg){
           return rc;
         }
       }else{
-        if( !pPager->journalStarted && !pPager->noSync ){
+        if( pPager->eState!=PAGER_WRITER_DBMOD ){
           pPg->flags |= PGHDR_NEED_SYNC;
-          pPager->needSync = 1;
         }
         PAGERTRACE(("APPEND %d page %d needSync=%d\n",
                 PAGERID(pPager), pPg->pgno,
@@ -34314,25 +42405,25 @@ static int pager_write(PgHdr *pPg){
 
   /* Update the database size and return.
   */
-  assert( pPager->state>=PAGER_SHARED );
   if( pPager->dbSize<pPg->pgno ){
     pPager->dbSize = pPg->pgno;
-    if( pPager->dbSize==(PAGER_MJ_PGNO(pPager)-1) ){
-      pPager->dbSize++;
-    }
   }
   return rc;
 }
 
 /*
-** This function is used to mark a data-page as writable. It uses 
-** pager_write() to open a journal file (if it is not already open)
-** and write the page *pData to the journal.
+** Mark a data page as writeable. This routine must be called before 
+** making changes to a page. The caller must check the return value 
+** of this function and be careful not to change any page data unless 
+** this routine returns SQLITE_OK.
 **
 ** The difference between this function and pager_write() is that this
 ** function also deals with the special case where 2 or more pages
 ** fit on a single disk sector. In this case all co-resident pages
 ** must have been written to the journal file before returning.
+**
+** If an error occurs, SQLITE_NOMEM or an IO error code is returned
+** as appropriate. Otherwise, SQLITE_OK.
 */
 SQLITE_PRIVATE int sqlite3PagerWrite(DbPage *pDbPage){
   int rc = SQLITE_OK;
@@ -34341,19 +42432,24 @@ SQLITE_PRIVATE int sqlite3PagerWrite(DbPage *pDbPage){
   Pager *pPager = pPg->pPager;
   Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
 
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( assert_pager_state(pPager) );
+
   if( nPagePerSector>1 ){
     Pgno nPageCount;          /* Total number of pages in database file */
     Pgno pg1;                 /* First page of the sector pPg is located on. */
-    int nPage;                /* Number of pages starting at pg1 to journal */
-    int ii;
-    int needSync = 0;
+    int nPage = 0;            /* Number of pages starting at pg1 to journal */
+    int ii;                   /* Loop counter */
+    int needSync = 0;         /* True if any page has PGHDR_NEED_SYNC */
 
-    /* Set the doNotSync flag to 1. This is because we cannot allow a journal
-    ** header to be written between the pages journaled by this function.
+    /* Set the doNotSyncSpill flag to 1. This is because we cannot allow
+    ** a journal header to be written between the pages journaled by
+    ** this function.
     */
     assert( !MEMDB );
-    assert( pPager->doNotSync==0 );
-    pPager->doNotSync = 1;
+    assert( pPager->doNotSyncSpill==0 );
+    pPager->doNotSyncSpill++;
 
     /* This trick assumes that both the page-size and sector-size are
     ** an integer power of 2. It sets variable pg1 to the identifier
@@ -34361,7 +42457,7 @@ SQLITE_PRIVATE int sqlite3PagerWrite(DbPage *pDbPage){
     */
     pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;
 
-    sqlite3PagerPagecount(pPager, (int *)&nPageCount);
+    nPageCount = pPager->dbSize;
     if( pPg->pgno>nPageCount ){
       nPage = (pPg->pgno - pg1)+1;
     }else if( (pg1+nPagePerSector-1)>nPageCount ){
@@ -34383,7 +42479,6 @@ SQLITE_PRIVATE int sqlite3PagerWrite(DbPage *pDbPage){
             rc = pager_write(pPage);
             if( pPage->flags&PGHDR_NEED_SYNC ){
               needSync = 1;
-              assert(pPager->needSync);
             }
             sqlite3PagerUnref(pPage);
           }
@@ -34402,20 +42497,19 @@ SQLITE_PRIVATE int sqlite3PagerWrite(DbPage *pDbPage){
     ** journal file must contain sync()ed copies of all of them
     ** before any of them can be written out to the database file.
     */
-    if( needSync ){
-      assert( !MEMDB && pPager->noSync==0 );
-      for(ii=0; ii<nPage && needSync; ii++){
+    if( rc==SQLITE_OK && needSync ){
+      assert( !MEMDB );
+      for(ii=0; ii<nPage; ii++){
         PgHdr *pPage = pager_lookup(pPager, pg1+ii);
         if( pPage ){
           pPage->flags |= PGHDR_NEED_SYNC;
           sqlite3PagerUnref(pPage);
         }
       }
-      assert(pPager->needSync);
     }
 
-    assert( pPager->doNotSync==1 );
-    pPager->doNotSync = 0;
+    assert( pPager->doNotSyncSpill==1 );
+    pPager->doNotSyncSpill--;
   }else{
     rc = pager_write(pDbPage);
   }
@@ -34441,187 +42535,157 @@ SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
 ** content no longer matters.
 **
 ** The overlying software layer calls this routine when all of the data
-** on the given page is unused.  The pager marks the page as clean so
+** on the given page is unused. The pager marks the page as clean so
 ** that it does not get written to disk.
 **
-** Tests show that this optimization, together with the
-** sqlite3PagerDontRollback() below, more than double the speed
-** of large INSERT operations and quadruple the speed of large DELETEs.
-**
-** When this routine is called, set the bit corresponding to pDbPage in
-** the Pager.pAlwaysRollback bitvec.  Subsequent calls to
-** sqlite3PagerDontRollback() for the same page will thereafter be ignored.
-** This is necessary to avoid a problem where a page with data is added to
-** the freelist during one part of a transaction then removed from the
-** freelist during a later part of the same transaction and reused for some
-** other purpose.  When it is first added to the freelist, this routine is
-** called.  When reused, the sqlite3PagerDontRollback() routine is called.
-** But because the page contains critical data, we still need to be sure it
-** gets rolled back in spite of the sqlite3PagerDontRollback() call.
+** Tests show that this optimization can quadruple the speed of large 
+** DELETE operations.
 */
-SQLITE_PRIVATE int sqlite3PagerDontWrite(DbPage *pDbPage){
-  PgHdr *pPg = pDbPage;
+SQLITE_PRIVATE void sqlite3PagerDontWrite(PgHdr *pPg){
   Pager *pPager = pPg->pPager;
-  int rc;
-
-  if( pPg->pgno>pPager->dbOrigSize ){
-    return SQLITE_OK;
+  if( (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
+    PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager)));
+    IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
+    pPg->flags |= PGHDR_DONT_WRITE;
+    pager_set_pagehash(pPg);
   }
-  if( pPager->pAlwaysRollback==0 ){
-    assert( pPager->pInJournal );
-    pPager->pAlwaysRollback = sqlite3BitvecCreate(pPager->dbOrigSize);
-    if( !pPager->pAlwaysRollback ){
-      return SQLITE_NOMEM;
-    }
-  }
-  rc = sqlite3BitvecSet(pPager->pAlwaysRollback, pPg->pgno);
-
-  if( rc==SQLITE_OK && (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
-    assert( pPager->state>=PAGER_SHARED );
-    if( pPager->dbSize==pPg->pgno && pPager->dbOrigSize<pPager->dbSize ){
-      /* If this pages is the last page in the file and the file has grown
-      ** during the current transaction, then do NOT mark the page as clean.
-      ** When the database file grows, we must make sure that the last page
-      ** gets written at least once so that the disk file will be the correct
-      ** size. If you do not write this page and the size of the file
-      ** on the disk ends up being too small, that can lead to database
-      ** corruption during the next transaction.
-      */
-    }else{
-      PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager)));
-      IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
-      pPg->flags |= PGHDR_DONT_WRITE;
-#ifdef SQLITE_CHECK_PAGES
-      pPg->pageHash = pager_pagehash(pPg);
-#endif
-    }
-  }
-  return rc;
 }
 
 /*
-** A call to this routine tells the pager that if a rollback occurs,
-** it is not necessary to restore the data on the given page.  This
-** means that the pager does not have to record the given page in the
-** rollback journal.
+** This routine is called to increment the value of the database file 
+** change-counter, stored as a 4-byte big-endian integer starting at 
+** byte offset 24 of the pager file.  The secondary change counter at
+** 92 is also updated, as is the SQLite version number at offset 96.
 **
-** If we have not yet actually read the content of this page (if
-** the PgHdr.needRead flag is set) then this routine acts as a promise
-** that we will never need to read the page content in the future.
-** so the needRead flag can be cleared at this point.
+** But this only happens if the pPager->changeCountDone flag is false.
+** To avoid excess churning of page 1, the update only happens once.
+** See also the pager_write_changecounter() routine that does an 
+** unconditional update of the change counters.
+**
+** If the isDirectMode flag is zero, then this is done by calling 
+** sqlite3PagerWrite() on page 1, then modifying the contents of the
+** page data. In this case the file will be updated when the current
+** transaction is committed.
+**
+** The isDirectMode flag may only be non-zero if the library was compiled
+** with the SQLITE_ENABLE_ATOMIC_WRITE macro defined. In this case,
+** if isDirect is non-zero, then the database file is updated directly
+** by writing an updated version of page 1 using a call to the 
+** sqlite3OsWrite() function.
 */
-SQLITE_PRIVATE void sqlite3PagerDontRollback(DbPage *pPg){
-  Pager *pPager = pPg->pPager;
-  TESTONLY( int rc; )  /* Return value from sqlite3BitvecSet() */
-
-  assert( pPager->state>=PAGER_RESERVED );
-
-  /* If the journal file is not open, or DontWrite() has been called on
-  ** this page (DontWrite() sets the Pager.pAlwaysRollback bit), then this
-  ** function is a no-op.
-  */
-  if( pPager->journalOpen==0 
-   || sqlite3BitvecTest(pPager->pAlwaysRollback, pPg->pgno)
-   || pPg->pgno>pPager->dbOrigSize
-  ){
-    return;
-  }
-
-#ifdef SQLITE_SECURE_DELETE
-  if( sqlite3BitvecTest(pPager->pInJournal, pPg->pgno)!=0
-   || pPg->pgno>pPager->dbOrigSize ){
-    return;
-  }
-#endif
-
-  /* If SECURE_DELETE is disabled, then there is no way that this
-  ** routine can be called on a page for which sqlite3PagerDontWrite()
-  ** has not been previously called during the same transaction.
-  ** And if DontWrite() has previously been called, the following
-  ** conditions must be met.
-  **
-  ** (Later:)  Not true.  If the database is corrupted by having duplicate
-  ** pages on the freelist (ex: corrupt9.test) then the following is not
-  ** necessarily true:
-  */
-  /* assert( !pPg->inJournal && (int)pPg->pgno <= pPager->dbOrigSize ); */
-
-  assert( pPager->pInJournal!=0 );
-  pPg->flags &= ~PGHDR_NEED_READ;
-
-  /* Failure to set the bits in the InJournal bit-vectors is benign.
-  ** It merely means that we might do some extra work to journal a page
-  ** that does not need to be journaled.  Nevertheless, be sure to test the
-  ** case where a malloc error occurs while trying to set a bit in a 
-  ** bit vector.
-  */
-  sqlite3BeginBenignMalloc();
-  TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
-  testcase( rc==SQLITE_NOMEM );
-  TESTONLY( rc = ) addToSavepointBitvecs(pPager, pPg->pgno);
-  testcase( rc==SQLITE_NOMEM );
-  sqlite3EndBenignMalloc();
-
-
-  PAGERTRACE(("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager)));
-  IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
-}
-
-
-/*
-** This routine is called to increment the database file change-counter,
-** stored at byte 24 of the pager file.
-*/
-static int pager_incr_changecounter(Pager *pPager, int isDirect){
-  PgHdr *pPgHdr;
-  u32 change_counter;
+static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
   int rc = SQLITE_OK;
 
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* Declare and initialize constant integer 'isDirect'. If the
+  ** atomic-write optimization is enabled in this build, then isDirect
+  ** is initialized to the value passed as the isDirectMode parameter
+  ** to this function. Otherwise, it is always set to zero.
+  **
+  ** The idea is that if the atomic-write optimization is not
+  ** enabled at compile time, the compiler can omit the tests of
+  ** 'isDirect' below, as well as the block enclosed in the
+  ** "if( isDirect )" condition.
+  */
 #ifndef SQLITE_ENABLE_ATOMIC_WRITE
-  assert( isDirect==0 );  /* isDirect is only true for atomic writes */
+# define DIRECT_MODE 0
+  assert( isDirectMode==0 );
+  UNUSED_PARAMETER(isDirectMode);
+#else
+# define DIRECT_MODE isDirectMode
 #endif
+
   if( !pPager->changeCountDone && pPager->dbSize>0 ){
+    PgHdr *pPgHdr;                /* Reference to page 1 */
+
+    assert( !pPager->tempFile && isOpen(pPager->fd) );
+
     /* Open page 1 of the file for writing. */
     rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
-    if( rc!=SQLITE_OK ) return rc;
+    assert( pPgHdr==0 || rc==SQLITE_OK );
 
-    if( !isDirect ){
+    /* If page one was fetched successfully, and this function is not
+    ** operating in direct-mode, make page 1 writable.  When not in 
+    ** direct mode, page 1 is always held in cache and hence the PagerGet()
+    ** above is always successful - hence the ALWAYS on rc==SQLITE_OK.
+    */
+    if( !DIRECT_MODE && ALWAYS(rc==SQLITE_OK) ){
       rc = sqlite3PagerWrite(pPgHdr);
-      if( rc!=SQLITE_OK ){
-        sqlite3PagerUnref(pPgHdr);
-        return rc;
+    }
+
+    if( rc==SQLITE_OK ){
+      /* Actually do the update of the change counter */
+      pager_write_changecounter(pPgHdr);
+
+      /* If running in direct mode, write the contents of page 1 to the file. */
+      if( DIRECT_MODE ){
+        const void *zBuf;
+        assert( pPager->dbFileSize>0 );
+        CODEC2(pPager, pPgHdr->pData, 1, 6, rc=SQLITE_NOMEM, zBuf);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3OsWrite(pPager->fd, zBuf, pPager->pageSize, 0);
+          pPager->aStat[PAGER_STAT_WRITE]++;
+        }
+        if( rc==SQLITE_OK ){
+          pPager->changeCountDone = 1;
+        }
+      }else{
+        pPager->changeCountDone = 1;
       }
     }
 
-    /* Increment the value just read and write it back to byte 24. */
-    change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
-    change_counter++;
-    put32bits(((char*)pPgHdr->pData)+24, change_counter);
-
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
-    if( isDirect && pPager->fd->pMethods ){
-      const void *zBuf = pPgHdr->pData;
-      assert( pPager->dbFileSize>0 );
-      rc = sqlite3OsWrite(pPager->fd, zBuf, pPager->pageSize, 0);
-    }
-#endif
-
     /* Release the page reference. */
     sqlite3PagerUnref(pPgHdr);
-    pPager->changeCountDone = 1;
   }
   return rc;
 }
 
 /*
-** Sync the pager file to disk.
+** Sync the database file to disk. This is a no-op for in-memory databases
+** or pages with the Pager.noSync flag set.
+**
+** If successful, or if called on a pager for which it is a no-op, this
+** function returns SQLITE_OK. Otherwise, an IO error code is returned.
 */
 SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager){
-  int rc;
-  if( MEMDB ){
-    rc = SQLITE_OK;
-  }else{
-    rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
+  int rc = SQLITE_OK;
+  if( !pPager->noSync ){
+    assert( !MEMDB );
+    rc = sqlite3OsSync(pPager->fd, pPager->syncFlags);
+  }else if( isOpen(pPager->fd) ){
+    assert( !MEMDB );
+    rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_SYNC_OMITTED, 0);
+    if( rc==SQLITE_NOTFOUND ){
+      rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+
+/*
+** This function may only be called while a write-transaction is active in
+** rollback. If the connection is in WAL mode, this call is a no-op. 
+** Otherwise, if the connection does not already have an EXCLUSIVE lock on 
+** the database file, an attempt is made to obtain one.
+**
+** If the EXCLUSIVE lock is already held or the attempt to obtain it is
+** successful, or the connection is in WAL mode, SQLITE_OK is returned.
+** Otherwise, either SQLITE_BUSY or an SQLITE_IOERR_XXX error code is 
+** returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerExclusiveLock(Pager *pPager){
+  int rc = SQLITE_OK;
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD 
+       || pPager->eState==PAGER_WRITER_DBMOD 
+       || pPager->eState==PAGER_WRITER_LOCKED 
+  );
+  assert( assert_pager_state(pPager) );
+  if( 0==pagerUseWal(pPager) ){
+    rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
   }
   return rc;
 }
@@ -34632,10 +42696,17 @@ SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager){
 ** journal file. zMaster may be NULL, which is interpreted as no master
 ** journal (a single database transaction).
 **
-** This routine ensures that the journal is synced, all dirty pages written
-** to the database file and the database file synced. The only thing that
-** remains to commit the transaction is to delete the journal file (or
-** master journal file if specified).
+** This routine ensures that:
+**
+**   * The database file change-counter is updated,
+**   * the journal is synced (unless the atomic-write optimization is used),
+**   * all dirty pages are written to the database file, 
+**   * the database file is truncated (if required), and
+**   * the database file synced. 
+**
+** The only thing that remains to commit the transaction is to finalize 
+** (delete, truncate or zero the first part of) the journal file (or 
+** delete the master journal file if specified).
 **
 ** Note that if zMaster==NULL, this does not overwrite a previous value
 ** passed to an sqlite3PagerCommitPhaseOne() call.
@@ -34646,235 +42717,313 @@ SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager){
 ** journal file in this case.
 */
 SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
-  Pager *pPager, 
-  const char *zMaster, 
-  int noSync
+  Pager *pPager,                  /* Pager object */
+  const char *zMaster,            /* If not NULL, the master journal name */
+  int noSync                      /* True to omit the xSync on the db file */
 ){
-  int rc = SQLITE_OK;
+  int rc = SQLITE_OK;             /* Return code */
 
-  if( pPager->errCode ){
-    return pPager->errCode;
-  }
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+       || pPager->eState==PAGER_ERROR
+  );
+  assert( assert_pager_state(pPager) );
 
-  /* If no changes have been made, we can leave the transaction early.
-  */
-  if( pPager->dbModified==0 &&
-        (pPager->journalMode!=PAGER_JOURNALMODE_DELETE ||
-          pPager->exclusiveMode!=0) ){
-    assert( pPager->dirtyCache==0 || pPager->journalOpen==0 );
-    return SQLITE_OK;
-  }
+  /* If a prior error occurred, report that error again. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
 
   PAGERTRACE(("DATABASE SYNC: File=%s zMaster=%s nSize=%d\n", 
       pPager->zFilename, zMaster, pPager->dbSize));
 
-  /* If this is an in-memory db, or no pages have been written to, or this
-  ** function has already been called, it is a no-op.
-  */
-  if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
-    PgHdr *pPg;
+  /* If no database changes have been made, return early. */
+  if( pPager->eState<PAGER_WRITER_CACHEMOD ) return SQLITE_OK;
 
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
-    /* The atomic-write optimization can be used if all of the
-    ** following are true:
-    **
-    **    + The file-system supports the atomic-write property for
-    **      blocks of size page-size, and
-    **    + This commit is not part of a multi-file transaction, and
-    **    + Exactly one page has been modified and store in the journal file.
-    **
-    ** If the optimization can be used, then the journal file will never
-    ** be created for this transaction.
+  if( MEMDB ){
+    /* If this is an in-memory db, or no pages have been written to, or this
+    ** function has already been called, it is mostly a no-op.  However, any
+    ** backup in progress needs to be restarted.
     */
-    int useAtomicWrite;
-    pPg = sqlite3PcacheDirtyList(pPager->pPCache);
-    useAtomicWrite = (
-        !zMaster && 
-        pPager->journalOpen &&
-        pPager->journalOff==jrnlBufferSize(pPager) && 
-        pPager->dbSize>=pPager->dbFileSize && 
-        (pPg==0 || pPg->pDirty==0)
-    );
-    assert( pPager->journalOpen || pPager->journalMode==PAGER_JOURNALMODE_OFF );
-    if( useAtomicWrite ){
-      /* Update the nRec field in the journal file. */
-      int offset = pPager->journalHdr + sizeof(aJournalMagic);
-      assert(pPager->nRec==1);
-      rc = write32bits(pPager->jfd, offset, pPager->nRec);
-
-      /* Update the db file change counter. The following call will modify
-      ** the in-memory representation of page 1 to include the updated
-      ** change counter and then write page 1 directly to the database
-      ** file. Because of the atomic-write property of the host file-system, 
-      ** this is safe.
-      */
+    sqlite3BackupRestart(pPager->pBackup);
+  }else{
+    if( pagerUseWal(pPager) ){
+      PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
+      PgHdr *pPageOne = 0;
+      if( pList==0 ){
+        /* Must have at least one page for the WAL commit flag.
+        ** Ticket [2d1a5c67dfc2363e44f29d9bbd57f] 2011-05-18 */
+        rc = sqlite3PagerGet(pPager, 1, &pPageOne);
+        pList = pPageOne;
+        pList->pDirty = 0;
+      }
+      assert( rc==SQLITE_OK );
+      if( ALWAYS(pList) ){
+        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1);
+      }
+      sqlite3PagerUnref(pPageOne);
       if( rc==SQLITE_OK ){
-        rc = pager_incr_changecounter(pPager, 1);
+        sqlite3PcacheCleanAll(pPager->pPCache);
       }
     }else{
-      rc = sqlite3JournalCreate(pPager->jfd);
-    }
-
-    if( !useAtomicWrite && rc==SQLITE_OK )
-#endif
-
-    /* If a master journal file name has already been written to the
-    ** journal file, then no sync is required. This happens when it is
-    ** written, then the process fails to upgrade from a RESERVED to an
-    ** EXCLUSIVE lock. The next time the process tries to commit the
-    ** transaction the m-j name will have already been written.
-    */
-    if( !pPager->setMaster ){
-      rc = pager_incr_changecounter(pPager, 0);
-      if( rc!=SQLITE_OK ) goto sync_exit;
-      if( pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
-#ifndef SQLITE_OMIT_AUTOVACUUM
-        if( pPager->dbSize<pPager->dbOrigSize ){
-          /* If this transaction has made the database smaller, then all pages
-          ** being discarded by the truncation must be written to the journal
-          ** file.
-          */
-          Pgno i;
-          Pgno iSkip = PAGER_MJ_PGNO(pPager);
-          Pgno dbSize = pPager->dbSize;
-          pPager->dbSize = pPager->dbOrigSize;
-          for( i=dbSize+1; i<=pPager->dbOrigSize; i++ ){
-            if( !sqlite3BitvecTest(pPager->pInJournal, i) && i!=iSkip ){
-              rc = sqlite3PagerGet(pPager, i, &pPg);
-              if( rc!=SQLITE_OK ) goto sync_exit;
-              rc = sqlite3PagerWrite(pPg);
-              sqlite3PagerUnref(pPg);
-              if( rc!=SQLITE_OK ) goto sync_exit;
-            }
-          } 
-          pPager->dbSize = dbSize;
-        }
-#endif
-        rc = writeMasterJournal(pPager, zMaster);
-        if( rc!=SQLITE_OK ) goto sync_exit;
-        rc = syncJournal(pPager);
-      }
-    }
-    if( rc!=SQLITE_OK ) goto sync_exit;
-
-    /* Write all dirty pages to the database file */
-    pPg = sqlite3PcacheDirtyList(pPager->pPCache);
-    rc = pager_write_pagelist(pPg);
-    if( rc!=SQLITE_OK ){
-      assert( rc!=SQLITE_IOERR_BLOCKED );
-      /* The error might have left the dirty list all fouled up here,
-      ** but that does not matter because if the if the dirty list did
-      ** get corrupted, then the transaction will roll back and
-      ** discard the dirty list.  There is an assert in
-      ** pager_get_all_dirty_pages() that verifies that no attempt
-      ** is made to use an invalid dirty list.
+      /* The following block updates the change-counter. Exactly how it
+      ** does this depends on whether or not the atomic-update optimization
+      ** was enabled at compile time, and if this transaction meets the 
+      ** runtime criteria to use the operation: 
+      **
+      **    * The file-system supports the atomic-write property for
+      **      blocks of size page-size, and 
+      **    * This commit is not part of a multi-file transaction, and
+      **    * Exactly one page has been modified and store in the journal file.
+      **
+      ** If the optimization was not enabled at compile time, then the
+      ** pager_incr_changecounter() function is called to update the change
+      ** counter in 'indirect-mode'. If the optimization is compiled in but
+      ** is not applicable to this transaction, call sqlite3JournalCreate()
+      ** to make sure the journal file has actually been created, then call
+      ** pager_incr_changecounter() to update the change-counter in indirect
+      ** mode. 
+      **
+      ** Otherwise, if the optimization is both enabled and applicable,
+      ** then call pager_incr_changecounter() to update the change-counter
+      ** in 'direct' mode. In this case the journal file will never be
+      ** created for this transaction.
       */
-      goto sync_exit;
+  #ifdef SQLITE_ENABLE_ATOMIC_WRITE
+      PgHdr *pPg;
+      assert( isOpen(pPager->jfd) 
+           || pPager->journalMode==PAGER_JOURNALMODE_OFF 
+           || pPager->journalMode==PAGER_JOURNALMODE_WAL 
+      );
+      if( !zMaster && isOpen(pPager->jfd) 
+       && pPager->journalOff==jrnlBufferSize(pPager) 
+       && pPager->dbSize>=pPager->dbOrigSize
+       && (0==(pPg = sqlite3PcacheDirtyList(pPager->pPCache)) || 0==pPg->pDirty)
+      ){
+        /* Update the db file change counter via the direct-write method. The 
+        ** following call will modify the in-memory representation of page 1 
+        ** to include the updated change counter and then write page 1 
+        ** directly to the database file. Because of the atomic-write 
+        ** property of the host file-system, this is safe.
+        */
+        rc = pager_incr_changecounter(pPager, 1);
+      }else{
+        rc = sqlite3JournalCreate(pPager->jfd);
+        if( rc==SQLITE_OK ){
+          rc = pager_incr_changecounter(pPager, 0);
+        }
+      }
+  #else
+      rc = pager_incr_changecounter(pPager, 0);
+  #endif
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+  
+      /* If this transaction has made the database smaller, then all pages
+      ** being discarded by the truncation must be written to the journal
+      ** file. This can only happen in auto-vacuum mode.
+      **
+      ** Before reading the pages with page numbers larger than the 
+      ** current value of Pager.dbSize, set dbSize back to the value
+      ** that it took at the start of the transaction. Otherwise, the
+      ** calls to sqlite3PagerGet() return zeroed pages instead of 
+      ** reading data from the database file.
+      */
+  #ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pPager->dbSize<pPager->dbOrigSize 
+       && pPager->journalMode!=PAGER_JOURNALMODE_OFF
+      ){
+        Pgno i;                                   /* Iterator variable */
+        const Pgno iSkip = PAGER_MJ_PGNO(pPager); /* Pending lock page */
+        const Pgno dbSize = pPager->dbSize;       /* Database image size */ 
+        pPager->dbSize = pPager->dbOrigSize;
+        for( i=dbSize+1; i<=pPager->dbOrigSize; i++ ){
+          if( !sqlite3BitvecTest(pPager->pInJournal, i) && i!=iSkip ){
+            PgHdr *pPage;             /* Page to journal */
+            rc = sqlite3PagerGet(pPager, i, &pPage);
+            if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+            rc = sqlite3PagerWrite(pPage);
+            sqlite3PagerUnref(pPage);
+            if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+          }
+        }
+        pPager->dbSize = dbSize;
+      } 
+  #endif
+  
+      /* Write the master journal name into the journal file. If a master 
+      ** journal file name has already been written to the journal file, 
+      ** or if zMaster is NULL (no master journal), then this call is a no-op.
+      */
+      rc = writeMasterJournal(pPager, zMaster);
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+  
+      /* Sync the journal file and write all dirty pages to the database.
+      ** If the atomic-update optimization is being used, this sync will not 
+      ** create the journal file or perform any real IO.
+      **
+      ** Because the change-counter page was just modified, unless the
+      ** atomic-update optimization is used it is almost certain that the
+      ** journal requires a sync here. However, in locking_mode=exclusive
+      ** on a system under memory pressure it is just possible that this is 
+      ** not the case. In this case it is likely enough that the redundant
+      ** xSync() call will be changed to a no-op by the OS anyhow. 
+      */
+      rc = syncJournal(pPager, 0);
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+  
+      rc = pager_write_pagelist(pPager,sqlite3PcacheDirtyList(pPager->pPCache));
+      if( rc!=SQLITE_OK ){
+        assert( rc!=SQLITE_IOERR_BLOCKED );
+        goto commit_phase_one_exit;
+      }
+      sqlite3PcacheCleanAll(pPager->pPCache);
+  
+      /* If the file on disk is not the same size as the database image,
+      ** then use pager_truncate to grow or shrink the file here.
+      */
+      if( pPager->dbSize!=pPager->dbFileSize ){
+        Pgno nNew = pPager->dbSize - (pPager->dbSize==PAGER_MJ_PGNO(pPager));
+        assert( pPager->eState==PAGER_WRITER_DBMOD );
+        rc = pager_truncate(pPager, nNew);
+        if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+      }
+  
+      /* Finally, sync the database file. */
+      if( !noSync ){
+        rc = sqlite3PagerSync(pPager);
+      }
+      IOTRACE(("DBSYNC %p\n", pPager))
     }
-    sqlite3PcacheCleanAll(pPager->pPCache);
-
-    if( pPager->dbSize<pPager->dbFileSize ){
-      assert( pPager->state>=PAGER_EXCLUSIVE );
-      rc = pager_truncate(pPager, pPager->dbSize);
-      if( rc!=SQLITE_OK ) goto sync_exit;
-    }
-
-    /* Sync the database file. */
-    if( !pPager->noSync && !noSync ){
-      rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
-    }
-    IOTRACE(("DBSYNC %p\n", pPager))
-
-    pPager->state = PAGER_SYNCED;
   }
 
-sync_exit:
-  if( rc==SQLITE_IOERR_BLOCKED ){
-    /* pager_incr_changecounter() may attempt to obtain an exclusive
-     * lock to spill the cache and return IOERR_BLOCKED. But since 
-     * there is no chance the cache is inconsistent, it is
-     * better to return SQLITE_BUSY.
-     */
-    rc = SQLITE_BUSY;
+commit_phase_one_exit:
+  if( rc==SQLITE_OK && !pagerUseWal(pPager) ){
+    pPager->eState = PAGER_WRITER_FINISHED;
   }
   return rc;
 }
 
 
 /*
-** Commit all changes to the database and release the write lock.
+** When this function is called, the database file has been completely
+** updated to reflect the changes made by the current transaction and
+** synced to disk. The journal file still exists in the file-system 
+** though, and if a failure occurs at this point it will eventually
+** be used as a hot-journal and the current transaction rolled back.
 **
-** If the commit fails for any reason, a rollback attempt is made
-** and an error code is returned.  If the commit worked, SQLITE_OK
-** is returned.
+** This function finalizes the journal file, either by deleting, 
+** truncating or partially zeroing it, so that it cannot be used 
+** for hot-journal rollback. Once this is done the transaction is
+** irrevocably committed.
+**
+** If an error occurs, an IO error code is returned and the pager
+** moves into the error state. Otherwise, SQLITE_OK is returned.
 */
 SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
-  int rc = SQLITE_OK;
+  int rc = SQLITE_OK;                  /* Return code */
 
-  if( pPager->errCode ){
-    return pPager->errCode;
-  }
-  if( pPager->state<PAGER_RESERVED ){
-    return SQLITE_ERROR;
-  }
-  if( pPager->dbModified==0 &&
-        (pPager->journalMode!=PAGER_JOURNALMODE_DELETE ||
-          pPager->exclusiveMode!=0) ){
-    assert( pPager->dirtyCache==0 || pPager->journalOpen==0 );
+  /* This routine should not be called if a prior error has occurred.
+  ** But if (due to a coding error elsewhere in the system) it does get
+  ** called, just return the same error code without doing anything. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
+
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_FINISHED
+       || (pagerUseWal(pPager) && pPager->eState==PAGER_WRITER_CACHEMOD)
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* An optimization. If the database was not actually modified during
+  ** this transaction, the pager is running in exclusive-mode and is
+  ** using persistent journals, then this function is a no-op.
+  **
+  ** The start of the journal file currently contains a single journal 
+  ** header with the nRec field set to 0. If such a journal is used as
+  ** a hot-journal during hot-journal rollback, 0 changes will be made
+  ** to the database file. So there is no need to zero the journal 
+  ** header. Since the pager is in exclusive mode, there is no need
+  ** to drop any locks either.
+  */
+  if( pPager->eState==PAGER_WRITER_LOCKED 
+   && pPager->exclusiveMode 
+   && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+  ){
+    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
+    pPager->eState = PAGER_READER;
     return SQLITE_OK;
   }
+
   PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));
-  assert( pPager->state==PAGER_SYNCED || MEMDB || !pPager->dirtyCache );
   rc = pager_end_transaction(pPager, pPager->setMaster);
-  rc = pager_error(pPager, rc);
-  return rc;
+  return pager_error(pPager, rc);
 }
 
 /*
-** Rollback all changes.  The database falls back to PAGER_SHARED mode.
-** All in-memory cache pages revert to their original data contents.
-** The journal is deleted.
+** If a write transaction is open, then all changes made within the 
+** transaction are reverted and the current write-transaction is closed.
+** The pager falls back to PAGER_READER state if successful, or PAGER_ERROR
+** state if an error occurs.
 **
-** This routine cannot fail unless some other process is not following
-** the correct locking protocol or unless some other
-** process is writing trash into the journal file (SQLITE_CORRUPT) or
-** unless a prior malloc() failed (SQLITE_NOMEM).  Appropriate error
-** codes are returned for all these occasions.  Otherwise,
-** SQLITE_OK is returned.
+** If the pager is already in PAGER_ERROR state when this function is called,
+** it returns Pager.errCode immediately. No work is performed in this case.
+**
+** Otherwise, in rollback mode, this function performs two functions:
+**
+**   1) It rolls back the journal file, restoring all database file and 
+**      in-memory cache pages to the state they were in when the transaction
+**      was opened, and
+**
+**   2) It finalizes the journal file, so that it is not used for hot
+**      rollback at any point in the future.
+**
+** Finalization of the journal file (task 2) is only performed if the 
+** rollback is successful.
+**
+** In WAL mode, all cache-entries containing data modified within the
+** current transaction are either expelled from the cache or reverted to
+** their pre-transaction state by re-reading data from the database or
+** WAL files. The WAL transaction is then closed.
 */
 SQLITE_PRIVATE int sqlite3PagerRollback(Pager *pPager){
-  int rc = SQLITE_OK;
+  int rc = SQLITE_OK;                  /* Return code */
   PAGERTRACE(("ROLLBACK %d\n", PAGERID(pPager)));
-  if( !pPager->dirtyCache || !pPager->journalOpen ){
-    rc = pager_end_transaction(pPager, pPager->setMaster);
-  }else if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
-    if( pPager->state>=PAGER_EXCLUSIVE ){
-      pager_playback(pPager, 0);
+
+  /* PagerRollback() is a no-op if called in READER or OPEN state. If
+  ** the pager is already in the ERROR state, the rollback is not 
+  ** attempted here. Instead, the error code is returned to the caller.
+  */
+  assert( assert_pager_state(pPager) );
+  if( pPager->eState==PAGER_ERROR ) return pPager->errCode;
+  if( pPager->eState<=PAGER_READER ) return SQLITE_OK;
+
+  if( pagerUseWal(pPager) ){
+    int rc2;
+    rc = sqlite3PagerSavepoint(pPager, SAVEPOINT_ROLLBACK, -1);
+    rc2 = pager_end_transaction(pPager, pPager->setMaster);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }else if( !isOpen(pPager->jfd) || pPager->eState==PAGER_WRITER_LOCKED ){
+    int eState = pPager->eState;
+    rc = pager_end_transaction(pPager, 0);
+    if( !MEMDB && eState>PAGER_WRITER_LOCKED ){
+      /* This can happen using journal_mode=off. Move the pager to the error 
+      ** state to indicate that the contents of the cache may not be trusted.
+      ** Any active readers will get SQLITE_ABORT.
+      */
+      pPager->errCode = SQLITE_ABORT;
+      pPager->eState = PAGER_ERROR;
+      return rc;
     }
-    rc = pPager->errCode;
   }else{
-    if( pPager->state==PAGER_RESERVED ){
-      int rc2;
-      rc = pager_playback(pPager, 0);
-      rc2 = pager_end_transaction(pPager, pPager->setMaster);
-      if( rc==SQLITE_OK ){
-        rc = rc2;
-      }
-    }else{
-      rc = pager_playback(pPager, 0);
-    }
-
-    if( !MEMDB ){
-      pPager->dbSizeValid = 0;
-    }
-
-    /* If an error occurs during a ROLLBACK, we can no longer trust the pager
-    ** cache. So call pager_error() on the way out to make any error 
-    ** persistent.
-    */
-    rc = pager_error(pPager, rc);
+    rc = pager_playback(pPager, 0);
   }
-  return rc;
+
+  assert( pPager->eState==PAGER_READER || rc!=SQLITE_OK );
+  assert( rc==SQLITE_OK || rc==SQLITE_FULL
+          || rc==SQLITE_NOMEM || (rc&0xFF)==SQLITE_IOERR );
+
+  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
+  ** cache. So call pager_error() on the way out to make any error persistent.
+  */
+  return pager_error(pPager, rc);
 }
 
 /*
@@ -34892,6 +43041,18 @@ SQLITE_PRIVATE int sqlite3PagerRefcount(Pager *pPager){
   return sqlite3PcacheRefCount(pPager->pPCache);
 }
 
+/*
+** Return the approximate number of bytes of memory currently
+** used by the pager and its associated cache.
+*/
+SQLITE_PRIVATE int sqlite3PagerMemUsed(Pager *pPager){
+  int perPageSize = pPager->pageSize + pPager->nExtra + sizeof(PgHdr)
+                                     + 5*sizeof(void*);
+  return perPageSize*sqlite3PcachePagecount(pPager->pPCache)
+           + sqlite3MallocSize(pPager)
+           + pPager->pageSize;
+}
+
 /*
 ** Return the number of references to the specified page.
 */
@@ -34908,35 +43069,69 @@ SQLITE_PRIVATE int *sqlite3PagerStats(Pager *pPager){
   a[0] = sqlite3PcacheRefCount(pPager->pPCache);
   a[1] = sqlite3PcachePagecount(pPager->pPCache);
   a[2] = sqlite3PcacheGetCachesize(pPager->pPCache);
-  a[3] = pPager->dbSizeValid ? (int) pPager->dbSize : -1;
-  a[4] = pPager->state;
+  a[3] = pPager->eState==PAGER_OPEN ? -1 : (int) pPager->dbSize;
+  a[4] = pPager->eState;
   a[5] = pPager->errCode;
-  a[6] = pPager->nHit;
-  a[7] = pPager->nMiss;
+  a[6] = pPager->aStat[PAGER_STAT_HIT];
+  a[7] = pPager->aStat[PAGER_STAT_MISS];
   a[8] = 0;  /* Used to be pPager->nOvfl */
   a[9] = pPager->nRead;
-  a[10] = pPager->nWrite;
+  a[10] = pPager->aStat[PAGER_STAT_WRITE];
   return a;
 }
-SQLITE_PRIVATE int sqlite3PagerIsMemdb(Pager *pPager){
-  return MEMDB;
-}
 #endif
 
 /*
-** Ensure that there are at least nSavepoint savepoints open.
+** Parameter eStat must be either SQLITE_DBSTATUS_CACHE_HIT or
+** SQLITE_DBSTATUS_CACHE_MISS. Before returning, *pnVal is incremented by the
+** current cache hit or miss count, according to the value of eStat. If the 
+** reset parameter is non-zero, the cache hit or miss count is zeroed before 
+** returning.
+*/
+SQLITE_PRIVATE void sqlite3PagerCacheStat(Pager *pPager, int eStat, int reset, int *pnVal){
+
+  assert( eStat==SQLITE_DBSTATUS_CACHE_HIT
+       || eStat==SQLITE_DBSTATUS_CACHE_MISS
+       || eStat==SQLITE_DBSTATUS_CACHE_WRITE
+  );
+
+  assert( SQLITE_DBSTATUS_CACHE_HIT+1==SQLITE_DBSTATUS_CACHE_MISS );
+  assert( SQLITE_DBSTATUS_CACHE_HIT+2==SQLITE_DBSTATUS_CACHE_WRITE );
+  assert( PAGER_STAT_HIT==0 && PAGER_STAT_MISS==1 && PAGER_STAT_WRITE==2 );
+
+  *pnVal += pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT];
+  if( reset ){
+    pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT] = 0;
+  }
+}
+
+/*
+** Return true if this is an in-memory pager.
+*/
+SQLITE_PRIVATE int sqlite3PagerIsMemdb(Pager *pPager){
+  return MEMDB;
+}
+
+/*
+** Check that there are at least nSavepoint savepoints open. If there are
+** currently less than nSavepoints open, then open one or more savepoints
+** to make up the difference. If the number of savepoints is already
+** equal to nSavepoint, then this function is a no-op.
+**
+** If a memory allocation fails, SQLITE_NOMEM is returned. If an error 
+** occurs while opening the sub-journal file, then an IO error code is
+** returned. Otherwise, SQLITE_OK.
 */
 SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
-  int rc = SQLITE_OK;
+  int rc = SQLITE_OK;                       /* Return code */
+  int nCurrent = pPager->nSavepoint;        /* Current number of savepoints */
 
-  if( nSavepoint>pPager->nSavepoint && pPager->useJournal ){
-    int ii;
-    PagerSavepoint *aNew;
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
 
-    /* Either there is no active journal or the sub-journal is open or 
-    ** the journal is always stored in memory */
-    assert( pPager->nSavepoint==0 || pPager->sjfd->pMethods ||
-            pPager->journalMode==PAGER_JOURNALMODE_MEMORY );
+  if( nSavepoint>nCurrent && pPager->useJournal ){
+    int ii;                                 /* Iterator variable */
+    PagerSavepoint *aNew;                   /* New Pager.aSavepoint array */
 
     /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
     ** if the allocation fails. Otherwise, zero the new portion in case a 
@@ -34948,83 +43143,123 @@ SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
     if( !aNew ){
       return SQLITE_NOMEM;
     }
-    memset(&aNew[pPager->nSavepoint], 0,
-        (nSavepoint - pPager->nSavepoint) * sizeof(PagerSavepoint)
-    );
+    memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
     pPager->aSavepoint = aNew;
-    ii = pPager->nSavepoint;
-    pPager->nSavepoint = nSavepoint;
 
     /* Populate the PagerSavepoint structures just allocated. */
-    for(/* no-op */; ii<nSavepoint; ii++){
-      assert( pPager->dbSizeValid );
+    for(ii=nCurrent; ii<nSavepoint; ii++){
       aNew[ii].nOrig = pPager->dbSize;
-      if( pPager->journalOpen && pPager->journalOff>0 ){
+      if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
         aNew[ii].iOffset = pPager->journalOff;
       }else{
         aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
       }
-      aNew[ii].iSubRec = pPager->stmtNRec;
+      aNew[ii].iSubRec = pPager->nSubRec;
       aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
       if( !aNew[ii].pInSavepoint ){
         return SQLITE_NOMEM;
       }
+      if( pagerUseWal(pPager) ){
+        sqlite3WalSavepoint(pPager->pWal, aNew[ii].aWalData);
+      }
+      pPager->nSavepoint = ii+1;
     }
-
-    /* Open the sub-journal, if it is not already opened. */
-    rc = openSubJournal(pPager);
+    assert( pPager->nSavepoint==nSavepoint );
+    assertTruncateConstraint(pPager);
   }
 
   return rc;
 }
 
 /*
+** This function is called to rollback or release (commit) a savepoint.
+** The savepoint to release or rollback need not be the most recently 
+** created savepoint.
+**
 ** Parameter op is always either SAVEPOINT_ROLLBACK or SAVEPOINT_RELEASE.
 ** If it is SAVEPOINT_RELEASE, then release and destroy the savepoint with
 ** index iSavepoint. If it is SAVEPOINT_ROLLBACK, then rollback all changes
-** that have occured since savepoint iSavepoint was created.
+** that have occurred since the specified savepoint was created.
 **
-** In either case, all savepoints with an index greater than iSavepoint 
-** are destroyed.
+** The savepoint to rollback or release is identified by parameter 
+** iSavepoint. A value of 0 means to operate on the outermost savepoint
+** (the first created). A value of (Pager.nSavepoint-1) means operate
+** on the most recently created savepoint. If iSavepoint is greater than
+** (Pager.nSavepoint-1), then this function is a no-op.
 **
-** If there are less than (iSavepoint+1) active savepoints when this 
-** function is called it is a no-op.
+** If a negative value is passed to this function, then the current
+** transaction is rolled back. This is different to calling 
+** sqlite3PagerRollback() because this function does not terminate
+** the transaction or unlock the database, it just restores the 
+** contents of the database to its original state. 
+**
+** In any case, all savepoints with an index greater than iSavepoint 
+** are destroyed. If this is a release operation (op==SAVEPOINT_RELEASE),
+** then savepoint iSavepoint is also destroyed.
+**
+** This function may return SQLITE_NOMEM if a memory allocation fails,
+** or an IO error code if an IO error occurs while rolling back a 
+** savepoint. If no errors occur, SQLITE_OK is returned.
 */ 
 SQLITE_PRIVATE int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint){
-  int rc = SQLITE_OK;
+  int rc = pPager->errCode;       /* Return code */
 
   assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
+  assert( iSavepoint>=0 || op==SAVEPOINT_ROLLBACK );
 
-  if( iSavepoint<pPager->nSavepoint ){
-    int ii;
-    int nNew = iSavepoint + (op==SAVEPOINT_ROLLBACK);
+  if( rc==SQLITE_OK && iSavepoint<pPager->nSavepoint ){
+    int ii;            /* Iterator variable */
+    int nNew;          /* Number of remaining savepoints after this op. */
+
+    /* Figure out how many savepoints will still be active after this
+    ** operation. Store this value in nNew. Then free resources associated 
+    ** with any savepoints that are destroyed by this operation.
+    */
+    nNew = iSavepoint + (( op==SAVEPOINT_RELEASE ) ? 0 : 1);
     for(ii=nNew; ii<pPager->nSavepoint; ii++){
       sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
     }
     pPager->nSavepoint = nNew;
 
-    if( op==SAVEPOINT_ROLLBACK && pPager->jfd->pMethods ){
+    /* If this is a release of the outermost savepoint, truncate 
+    ** the sub-journal to zero bytes in size. */
+    if( op==SAVEPOINT_RELEASE ){
+      if( nNew==0 && isOpen(pPager->sjfd) ){
+        /* Only truncate if it is an in-memory sub-journal. */
+        if( sqlite3IsMemJournal(pPager->sjfd) ){
+          rc = sqlite3OsTruncate(pPager->sjfd, 0);
+          assert( rc==SQLITE_OK );
+        }
+        pPager->nSubRec = 0;
+      }
+    }
+    /* Else this is a rollback operation, playback the specified savepoint.
+    ** If this is a temp-file, it is possible that the journal file has
+    ** not yet been opened. In this case there have been no changes to
+    ** the database file, so the playback operation can be skipped.
+    */
+    else if( pagerUseWal(pPager) || isOpen(pPager->jfd) ){
       PagerSavepoint *pSavepoint = (nNew==0)?0:&pPager->aSavepoint[nNew-1];
       rc = pagerPlaybackSavepoint(pPager, pSavepoint);
       assert(rc!=SQLITE_DONE);
     }
-  
-    /* If this is a release of the outermost savepoint, truncate 
-    ** the sub-journal. */
-    if( nNew==0 && op==SAVEPOINT_RELEASE && pPager->sjfd->pMethods ){
-      assert( rc==SQLITE_OK );
-      rc = sqlite3OsTruncate(pPager->sjfd, 0);
-      pPager->stmtNRec = 0;
-    }
   }
+
   return rc;
 }
 
 /*
 ** Return the full pathname of the database file.
+**
+** Except, if the pager is in-memory only, then return an empty string if
+** nullIfMemDb is true.  This routine is called with nullIfMemDb==1 when
+** used to report the filename to the user, for compatibility with legacy
+** behavior.  But when the Btree needs to know the filename for matching to
+** shared cache, it uses nullIfMemDb==0 so that in-memory databases can
+** participate in shared-cache.
 */
-SQLITE_PRIVATE const char *sqlite3PagerFilename(Pager *pPager){
-  return pPager->zFilename;
+SQLITE_PRIVATE const char *sqlite3PagerFilename(Pager *pPager, int nullIfMemDb){
+  return (nullIfMemDb && pPager->memDb) ? "" : pPager->zFilename;
 }
 
 /*
@@ -35043,13 +43278,6 @@ SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager *pPager){
   return pPager->fd;
 }
 
-/*
-** Return the directory of the database file.
-*/
-SQLITE_PRIVATE const char *sqlite3PagerDirname(Pager *pPager){
-  return pPager->zDirectory;
-}
-
 /*
 ** Return the full pathname of the journal file.
 */
@@ -35067,15 +43295,24 @@ SQLITE_PRIVATE int sqlite3PagerNosync(Pager *pPager){
 
 #ifdef SQLITE_HAS_CODEC
 /*
-** Set the codec for this pager
+** Set or retrieve the codec for this pager
 */
 SQLITE_PRIVATE void sqlite3PagerSetCodec(
   Pager *pPager,
   void *(*xCodec)(void*,void*,Pgno,int),
-  void *pCodecArg
+  void (*xCodecSizeChng)(void*,int,int),
+  void (*xCodecFree)(void*),
+  void *pCodec
 ){
-  pPager->xCodec = xCodec;
-  pPager->pCodecArg = pCodecArg;
+  if( pPager->xCodecFree ) pPager->xCodecFree(pPager->pCodec);
+  pPager->xCodec = pPager->memDb ? 0 : xCodec;
+  pPager->xCodecSizeChng = xCodecSizeChng;
+  pPager->xCodecFree = xCodecFree;
+  pPager->pCodec = pCodec;
+  pagerReportSize(pPager);
+}
+SQLITE_PRIVATE void *sqlite3PagerGetCodec(Pager *pPager){
+  return pPager->pCodec;
 }
 #endif
 
@@ -35101,13 +43338,29 @@ SQLITE_PRIVATE void sqlite3PagerSetCodec(
 ** moved as part of a database reorganization just before the transaction 
 ** is being committed. In this case, it is guaranteed that the database page 
 ** pPg refers to will not be written to again within this transaction.
+**
+** This function may return SQLITE_NOMEM or an IO error code if an error
+** occurs. Otherwise, it returns SQLITE_OK.
 */
 SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
-  PgHdr *pPgOld;  /* The page being overwritten. */
-  Pgno needSyncPgno = 0;
-  int rc;
+  PgHdr *pPgOld;               /* The page being overwritten. */
+  Pgno needSyncPgno = 0;       /* Old value of pPg->pgno, if sync is required */
+  int rc;                      /* Return code */
+  Pgno origPgno;               /* The original page number */
 
   assert( pPg->nRef>0 );
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* In order to be able to rollback, an in-memory database must journal
+  ** the page we are moving from.
+  */
+  if( MEMDB ){
+    rc = sqlite3PagerWrite(pPg);
+    if( rc ) return rc;
+  }
 
   /* If the page being moved is dirty and has not been saved by the latest
   ** savepoint, then save the current contents of the page into the 
@@ -35121,9 +43374,13 @@ SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, i
   **
   ** If page X were not written to the sub-journal here, it would not
   ** be possible to restore its contents when the "ROLLBACK TO one"
-  ** statement were processed.
+  ** statement were is processed.
+  **
+  ** subjournalPage() may need to allocate space to store pPg->pgno into
+  ** one or more savepoint bitvecs. This is the reason this function
+  ** may return SQLITE_NOMEM.
   */
-  if( pPg->flags&PGHDR_DIRTY 
+  if( pPg->flags&PGHDR_DIRTY
    && subjRequiresPage(pPg)
    && SQLITE_OK!=(rc = subjournalPage(pPg))
   ){
@@ -35134,8 +43391,6 @@ SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, i
       PAGERID(pPager), pPg->pgno, (pPg->flags&PGHDR_NEED_SYNC)?1:0, pgno));
   IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
 
-  pager_get_content(pPg);
-
   /* If the journal needs to be sync()ed before page pPg->pgno can
   ** be written to, store pPg->pgno in local variable needSyncPgno.
   **
@@ -35147,11 +43402,10 @@ SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, i
     needSyncPgno = pPg->pgno;
     assert( pageInJournal(pPg) || pPg->pgno>pPager->dbOrigSize );
     assert( pPg->flags&PGHDR_DIRTY );
-    assert( pPager->needSync );
   }
 
   /* If the cache contains a page with page-number pgno, remove it
-  ** from its hash chain. Also, if the PgHdr.needSync was set for 
+  ** from its hash chain. Also, if the PGHDR_NEED_SYNC flag was set for 
   ** page pgno before the 'move' operation, it needs to be retained 
   ** for the page moved there.
   */
@@ -35160,23 +43414,35 @@ SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, i
   assert( !pPgOld || pPgOld->nRef==1 );
   if( pPgOld ){
     pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
+    if( MEMDB ){
+      /* Do not discard pages from an in-memory database since we might
+      ** need to rollback later.  Just move the page out of the way. */
+      sqlite3PcacheMove(pPgOld, pPager->dbSize+1);
+    }else{
+      sqlite3PcacheDrop(pPgOld);
+    }
   }
 
+  origPgno = pPg->pgno;
   sqlite3PcacheMove(pPg, pgno);
-  if( pPgOld ){
-    sqlite3PcacheDrop(pPgOld);
-  }
-
   sqlite3PcacheMakeDirty(pPg);
-  pPager->dirtyCache = 1;
-  pPager->dbModified = 1;
+
+  /* For an in-memory database, make sure the original page continues
+  ** to exist, in case the transaction needs to roll back.  Use pPgOld
+  ** as the original page since it has already been allocated.
+  */
+  if( MEMDB ){
+    assert( pPgOld );
+    sqlite3PcacheMove(pPgOld, origPgno);
+    sqlite3PagerUnref(pPgOld);
+  }
 
   if( needSyncPgno ){
     /* If needSyncPgno is non-zero, then the journal file needs to be 
     ** sync()ed before any data is written to database file page needSyncPgno.
     ** Currently, no such page exists in the page-cache and the 
     ** "is journaled" bitvec flag has been set. This needs to be remedied by
-    ** loading the page into the pager-cache and setting the PgHdr.needSync 
+    ** loading the page into the pager-cache and setting the PGHDR_NEED_SYNC
     ** flag.
     **
     ** If the attempt to load the page into the page-cache fails, (due
@@ -35185,21 +43451,16 @@ SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, i
     ** this transaction, it may be written to the database file before
     ** it is synced into the journal file. This way, it may end up in
     ** the journal file twice, but that is not a problem.
-    **
-    ** The sqlite3PagerGet() call may cause the journal to sync. So make
-    ** sure the Pager.needSync flag is set too.
     */
     PgHdr *pPgHdr;
-    assert( pPager->needSync );
     rc = sqlite3PagerGet(pPager, needSyncPgno, &pPgHdr);
     if( rc!=SQLITE_OK ){
-      if( pPager->pInJournal && needSyncPgno<=pPager->dbOrigSize ){
-        sqlite3BitvecClear(pPager->pInJournal, needSyncPgno);
+      if( needSyncPgno<=pPager->dbOrigSize ){
+        assert( pPager->pTmpSpace!=0 );
+        sqlite3BitvecClear(pPager->pInJournal, needSyncPgno, pPager->pTmpSpace);
       }
       return rc;
     }
-    pPager->needSync = 1;
-    assert( pPager->noSync==0 && !MEMDB );
     pPgHdr->flags |= PGHDR_NEED_SYNC;
     sqlite3PcacheMakeDirty(pPgHdr);
     sqlite3PagerUnref(pPgHdr);
@@ -35222,8 +43483,7 @@ SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *pPg){
 ** allocated along with the specified page.
 */
 SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *pPg){
-  Pager *pPager = pPg->pPager;
-  return (pPager?pPg->pExtra:0);
+  return pPg->pExtra;
 }
 
 /*
@@ -35242,58 +43502,3476 @@ SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *pPager, int eMode){
             || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
   assert( PAGER_LOCKINGMODE_QUERY<0 );
   assert( PAGER_LOCKINGMODE_NORMAL>=0 && PAGER_LOCKINGMODE_EXCLUSIVE>=0 );
-  if( eMode>=0 && !pPager->tempFile ){
+  assert( pPager->exclusiveMode || 0==sqlite3WalHeapMemory(pPager->pWal) );
+  if( eMode>=0 && !pPager->tempFile && !sqlite3WalHeapMemory(pPager->pWal) ){
     pPager->exclusiveMode = (u8)eMode;
   }
   return (int)pPager->exclusiveMode;
 }
 
 /*
-** Get/set the journal-mode for this pager. Parameter eMode must be one of:
+** Set the journal-mode for this pager. Parameter eMode must be one of:
 **
-**    PAGER_JOURNALMODE_QUERY
 **    PAGER_JOURNALMODE_DELETE
 **    PAGER_JOURNALMODE_TRUNCATE
 **    PAGER_JOURNALMODE_PERSIST
 **    PAGER_JOURNALMODE_OFF
+**    PAGER_JOURNALMODE_MEMORY
+**    PAGER_JOURNALMODE_WAL
 **
-** If the parameter is not _QUERY, then the journal-mode is set to the
-** value specified.
+** The journalmode is set to the value specified if the change is allowed.
+** The change may be disallowed for the following reasons:
 **
-** The returned indicate the current (possibly updated)
-** journal-mode.
+**   *  An in-memory database can only have its journal_mode set to _OFF
+**      or _MEMORY.
+**
+**   *  Temporary databases cannot have _WAL journalmode.
+**
+** The returned indicate the current (possibly updated) journal-mode.
 */
-SQLITE_PRIVATE int sqlite3PagerJournalMode(Pager *pPager, int eMode){
-  if( !MEMDB ){
-    assert( eMode==PAGER_JOURNALMODE_QUERY
-              || eMode==PAGER_JOURNALMODE_DELETE
-              || eMode==PAGER_JOURNALMODE_TRUNCATE
-              || eMode==PAGER_JOURNALMODE_PERSIST
-              || eMode==PAGER_JOURNALMODE_OFF 
-              || eMode==PAGER_JOURNALMODE_MEMORY );
-    assert( PAGER_JOURNALMODE_QUERY<0 );
-    if( eMode>=0 ){
-      pPager->journalMode = (u8)eMode;
-    }else{
-      assert( eMode==PAGER_JOURNALMODE_QUERY );
+SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *pPager, int eMode){
+  u8 eOld = pPager->journalMode;    /* Prior journalmode */
+
+#ifdef SQLITE_DEBUG
+  /* The print_pager_state() routine is intended to be used by the debugger
+  ** only.  We invoke it once here to suppress a compiler warning. */
+  print_pager_state(pPager);
+#endif
+
+
+  /* The eMode parameter is always valid */
+  assert(      eMode==PAGER_JOURNALMODE_DELETE
+            || eMode==PAGER_JOURNALMODE_TRUNCATE
+            || eMode==PAGER_JOURNALMODE_PERSIST
+            || eMode==PAGER_JOURNALMODE_OFF 
+            || eMode==PAGER_JOURNALMODE_WAL 
+            || eMode==PAGER_JOURNALMODE_MEMORY );
+
+  /* This routine is only called from the OP_JournalMode opcode, and
+  ** the logic there will never allow a temporary file to be changed
+  ** to WAL mode.
+  */
+  assert( pPager->tempFile==0 || eMode!=PAGER_JOURNALMODE_WAL );
+
+  /* Do allow the journalmode of an in-memory database to be set to
+  ** anything other than MEMORY or OFF
+  */
+  if( MEMDB ){
+    assert( eOld==PAGER_JOURNALMODE_MEMORY || eOld==PAGER_JOURNALMODE_OFF );
+    if( eMode!=PAGER_JOURNALMODE_MEMORY && eMode!=PAGER_JOURNALMODE_OFF ){
+      eMode = eOld;
     }
   }
+
+  if( eMode!=eOld ){
+
+    /* Change the journal mode. */
+    assert( pPager->eState!=PAGER_ERROR );
+    pPager->journalMode = (u8)eMode;
+
+    /* When transistioning from TRUNCATE or PERSIST to any other journal
+    ** mode except WAL, unless the pager is in locking_mode=exclusive mode,
+    ** delete the journal file.
+    */
+    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
+    assert( (PAGER_JOURNALMODE_PERSIST & 5)==1 );
+    assert( (PAGER_JOURNALMODE_DELETE & 5)==0 );
+    assert( (PAGER_JOURNALMODE_MEMORY & 5)==4 );
+    assert( (PAGER_JOURNALMODE_OFF & 5)==0 );
+    assert( (PAGER_JOURNALMODE_WAL & 5)==5 );
+
+    assert( isOpen(pPager->fd) || pPager->exclusiveMode );
+    if( !pPager->exclusiveMode && (eOld & 5)==1 && (eMode & 1)==0 ){
+
+      /* In this case we would like to delete the journal file. If it is
+      ** not possible, then that is not a problem. Deleting the journal file
+      ** here is an optimization only.
+      **
+      ** Before deleting the journal file, obtain a RESERVED lock on the
+      ** database file. This ensures that the journal file is not deleted
+      ** while it is in use by some other client.
+      */
+      sqlite3OsClose(pPager->jfd);
+      if( pPager->eLock>=RESERVED_LOCK ){
+        sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+      }else{
+        int rc = SQLITE_OK;
+        int state = pPager->eState;
+        assert( state==PAGER_OPEN || state==PAGER_READER );
+        if( state==PAGER_OPEN ){
+          rc = sqlite3PagerSharedLock(pPager);
+        }
+        if( pPager->eState==PAGER_READER ){
+          assert( rc==SQLITE_OK );
+          rc = pagerLockDb(pPager, RESERVED_LOCK);
+        }
+        if( rc==SQLITE_OK ){
+          sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+        }
+        if( rc==SQLITE_OK && state==PAGER_READER ){
+          pagerUnlockDb(pPager, SHARED_LOCK);
+        }else if( state==PAGER_OPEN ){
+          pager_unlock(pPager);
+        }
+        assert( state==pPager->eState );
+      }
+    }
+  }
+
+  /* Return the new journal mode */
   return (int)pPager->journalMode;
 }
 
+/*
+** Return the current journal mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager *pPager){
+  return (int)pPager->journalMode;
+}
+
+/*
+** Return TRUE if the pager is in a state where it is OK to change the
+** journalmode.  Journalmode changes can only happen when the database
+** is unmodified.
+*/
+SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
+  assert( assert_pager_state(pPager) );
+  if( pPager->eState>=PAGER_WRITER_CACHEMOD ) return 0;
+  if( NEVER(isOpen(pPager->jfd) && pPager->journalOff>0) ) return 0;
+  return 1;
+}
+
 /*
 ** Get/set the size-limit used for persistent journal files.
+**
+** Setting the size limit to -1 means no limit is enforced.
+** An attempt to set a limit smaller than -1 is a no-op.
 */
 SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
   if( iLimit>=-1 ){
     pPager->journalSizeLimit = iLimit;
+    sqlite3WalLimit(pPager->pWal, iLimit);
   }
   return pPager->journalSizeLimit;
 }
 
+/*
+** Return a pointer to the pPager->pBackup variable. The backup module
+** in backup.c maintains the content of this variable. This module
+** uses it opaquely as an argument to sqlite3BackupRestart() and
+** sqlite3BackupUpdate() only.
+*/
+SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager *pPager){
+  return &pPager->pBackup;
+}
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Unless this is an in-memory or temporary database, clear the pager cache.
+*/
+SQLITE_PRIVATE void sqlite3PagerClearCache(Pager *pPager){
+  if( !MEMDB && pPager->tempFile==0 ) pager_reset(pPager);
+}
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** This function is called when the user invokes "PRAGMA wal_checkpoint",
+** "PRAGMA wal_blocking_checkpoint" or calls the sqlite3_wal_checkpoint()
+** or wal_blocking_checkpoint() API functions.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
+*/
+SQLITE_PRIVATE int sqlite3PagerCheckpoint(Pager *pPager, int eMode, int *pnLog, int *pnCkpt){
+  int rc = SQLITE_OK;
+  if( pPager->pWal ){
+    rc = sqlite3WalCheckpoint(pPager->pWal, eMode,
+        pPager->xBusyHandler, pPager->pBusyHandlerArg,
+        pPager->ckptSyncFlags, pPager->pageSize, (u8 *)pPager->pTmpSpace,
+        pnLog, pnCkpt
+    );
+  }
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3PagerWalCallback(Pager *pPager){
+  return sqlite3WalCallback(pPager->pWal);
+}
+
+/*
+** Return true if the underlying VFS for the given pager supports the
+** primitives necessary for write-ahead logging.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager){
+  const sqlite3_io_methods *pMethods = pPager->fd->pMethods;
+  return pPager->exclusiveMode || (pMethods->iVersion>=2 && pMethods->xShmMap);
+}
+
+/*
+** Attempt to take an exclusive lock on the database file. If a PENDING lock
+** is obtained instead, immediately release it.
+*/
+static int pagerExclusiveLock(Pager *pPager){
+  int rc;                         /* Return code */
+
+  assert( pPager->eLock==SHARED_LOCK || pPager->eLock==EXCLUSIVE_LOCK );
+  rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+  if( rc!=SQLITE_OK ){
+    /* If the attempt to grab the exclusive lock failed, release the 
+    ** pending lock that may have been obtained instead.  */
+    pagerUnlockDb(pPager, SHARED_LOCK);
+  }
+
+  return rc;
+}
+
+/*
+** Call sqlite3WalOpen() to open the WAL handle. If the pager is in 
+** exclusive-locking mode when this function is called, take an EXCLUSIVE
+** lock on the database file and use heap-memory to store the wal-index
+** in. Otherwise, use the normal shared-memory.
+*/
+static int pagerOpenWal(Pager *pPager){
+  int rc = SQLITE_OK;
+
+  assert( pPager->pWal==0 && pPager->tempFile==0 );
+  assert( pPager->eLock==SHARED_LOCK || pPager->eLock==EXCLUSIVE_LOCK );
+
+  /* If the pager is already in exclusive-mode, the WAL module will use 
+  ** heap-memory for the wal-index instead of the VFS shared-memory 
+  ** implementation. Take the exclusive lock now, before opening the WAL
+  ** file, to make sure this is safe.
+  */
+  if( pPager->exclusiveMode ){
+    rc = pagerExclusiveLock(pPager);
+  }
+
+  /* Open the connection to the log file. If this operation fails, 
+  ** (e.g. due to malloc() failure), return an error code.
+  */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3WalOpen(pPager->pVfs, 
+        pPager->fd, pPager->zWal, pPager->exclusiveMode,
+        pPager->journalSizeLimit, &pPager->pWal
+    );
+  }
+
+  return rc;
+}
+
+
+/*
+** The caller must be holding a SHARED lock on the database file to call
+** this function.
+**
+** If the pager passed as the first argument is open on a real database
+** file (not a temp file or an in-memory database), and the WAL file
+** is not already open, make an attempt to open it now. If successful,
+** return SQLITE_OK. If an error occurs or the VFS used by the pager does 
+** not support the xShmXXX() methods, return an error code. *pbOpen is
+** not modified in either case.
+**
+** If the pager is open on a temp-file (or in-memory database), or if
+** the WAL file is already open, set *pbOpen to 1 and return SQLITE_OK
+** without doing anything.
+*/
+SQLITE_PRIVATE int sqlite3PagerOpenWal(
+  Pager *pPager,                  /* Pager object */
+  int *pbOpen                     /* OUT: Set to true if call is a no-op */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState==PAGER_OPEN   || pbOpen );
+  assert( pPager->eState==PAGER_READER || !pbOpen );
+  assert( pbOpen==0 || *pbOpen==0 );
+  assert( pbOpen!=0 || (!pPager->tempFile && !pPager->pWal) );
+
+  if( !pPager->tempFile && !pPager->pWal ){
+    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;
+
+    /* Close any rollback journal previously open */
+    sqlite3OsClose(pPager->jfd);
+
+    rc = pagerOpenWal(pPager);
+    if( rc==SQLITE_OK ){
+      pPager->journalMode = PAGER_JOURNALMODE_WAL;
+      pPager->eState = PAGER_OPEN;
+    }
+  }else{
+    *pbOpen = 1;
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to close the connection to the log file prior
+** to switching from WAL to rollback mode.
+**
+** Before closing the log file, this function attempts to take an 
+** EXCLUSIVE lock on the database file. If this cannot be obtained, an
+** error (SQLITE_BUSY) is returned and the log connection is not closed.
+** If successful, the EXCLUSIVE lock is not released before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerCloseWal(Pager *pPager){
+  int rc = SQLITE_OK;
+
+  assert( pPager->journalMode==PAGER_JOURNALMODE_WAL );
+
+  /* If the log file is not already open, but does exist in the file-system,
+  ** it may need to be checkpointed before the connection can switch to
+  ** rollback mode. Open it now so this can happen.
+  */
+  if( !pPager->pWal ){
+    int logexists = 0;
+    rc = pagerLockDb(pPager, SHARED_LOCK);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &logexists
+      );
+    }
+    if( rc==SQLITE_OK && logexists ){
+      rc = pagerOpenWal(pPager);
+    }
+  }
+    
+  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
+  ** the database file, the log and log-summary files will be deleted.
+  */
+  if( rc==SQLITE_OK && pPager->pWal ){
+    rc = pagerExclusiveLock(pPager);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3WalClose(pPager->pWal, pPager->ckptSyncFlags,
+                           pPager->pageSize, (u8*)pPager->pTmpSpace);
+      pPager->pWal = 0;
+    }
+  }
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/*
+** A read-lock must be held on the pager when this function is called. If
+** the pager is in WAL mode and the WAL file currently contains one or more
+** frames, return the size in bytes of the page images stored within the
+** WAL frames. Otherwise, if this is not a WAL database or the WAL file
+** is empty, return 0.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalFramesize(Pager *pPager){
+  assert( pPager->eState==PAGER_READER );
+  return sqlite3WalFramesize(pPager->pWal);
+}
+#endif
+
+#ifdef SQLITE_HAS_CODEC
+/*
+** This function is called by the wal module when writing page content
+** into the log file.
+**
+** This function returns a pointer to a buffer containing the encrypted
+** page content. If a malloc fails, this function may return NULL.
+*/
+SQLITE_PRIVATE void *sqlite3PagerCodec(PgHdr *pPg){
+  void *aData = 0;
+  CODEC2(pPg->pPager, pPg->pData, pPg->pgno, 6, return 0, aData);
+  return aData;
+}
+#endif /* SQLITE_HAS_CODEC */
+
+#endif /* !SQLITE_OMIT_WAL */
+
 #endif /* SQLITE_OMIT_DISKIO */
 
 /************** End of pager.c ***********************************************/
+/************** Begin file wal.c *********************************************/
+/*
+** 2010 February 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the implementation of a write-ahead log (WAL) used in 
+** "journal_mode=WAL" mode.
+**
+** WRITE-AHEAD LOG (WAL) FILE FORMAT
+**
+** A WAL file consists of a header followed by zero or more "frames".
+** Each frame records the revised content of a single page from the
+** database file.  All changes to the database are recorded by writing
+** frames into the WAL.  Transactions commit when a frame is written that
+** contains a commit marker.  A single WAL can and usually does record 
+** multiple transactions.  Periodically, the content of the WAL is
+** transferred back into the database file in an operation called a
+** "checkpoint".
+**
+** A single WAL file can be used multiple times.  In other words, the
+** WAL can fill up with frames and then be checkpointed and then new
+** frames can overwrite the old ones.  A WAL always grows from beginning
+** toward the end.  Checksums and counters attached to each frame are
+** used to determine which frames within the WAL are valid and which
+** are leftovers from prior checkpoints.
+**
+** The WAL header is 32 bytes in size and consists of the following eight
+** big-endian 32-bit unsigned integer values:
+**
+**     0: Magic number.  0x377f0682 or 0x377f0683
+**     4: File format version.  Currently 3007000
+**     8: Database page size.  Example: 1024
+**    12: Checkpoint sequence number
+**    16: Salt-1, random integer incremented with each checkpoint
+**    20: Salt-2, a different random integer changing with each ckpt
+**    24: Checksum-1 (first part of checksum for first 24 bytes of header).
+**    28: Checksum-2 (second part of checksum for first 24 bytes of header).
+**
+** Immediately following the wal-header are zero or more frames. Each
+** frame consists of a 24-byte frame-header followed by a <page-size> bytes
+** of page data. The frame-header is six big-endian 32-bit unsigned 
+** integer values, as follows:
+**
+**     0: Page number.
+**     4: For commit records, the size of the database image in pages 
+**        after the commit. For all other records, zero.
+**     8: Salt-1 (copied from the header)
+**    12: Salt-2 (copied from the header)
+**    16: Checksum-1.
+**    20: Checksum-2.
+**
+** A frame is considered valid if and only if the following conditions are
+** true:
+**
+**    (1) The salt-1 and salt-2 values in the frame-header match
+**        salt values in the wal-header
+**
+**    (2) The checksum values in the final 8 bytes of the frame-header
+**        exactly match the checksum computed consecutively on the
+**        WAL header and the first 8 bytes and the content of all frames
+**        up to and including the current frame.
+**
+** The checksum is computed using 32-bit big-endian integers if the
+** magic number in the first 4 bytes of the WAL is 0x377f0683 and it
+** is computed using little-endian if the magic number is 0x377f0682.
+** The checksum values are always stored in the frame header in a
+** big-endian format regardless of which byte order is used to compute
+** the checksum.  The checksum is computed by interpreting the input as
+** an even number of unsigned 32-bit integers: x[0] through x[N].  The
+** algorithm used for the checksum is as follows:
+** 
+**   for i from 0 to n-1 step 2:
+**     s0 += x[i] + s1;
+**     s1 += x[i+1] + s0;
+**   endfor
+**
+** Note that s0 and s1 are both weighted checksums using fibonacci weights
+** in reverse order (the largest fibonacci weight occurs on the first element
+** of the sequence being summed.)  The s1 value spans all 32-bit 
+** terms of the sequence whereas s0 omits the final term.
+**
+** On a checkpoint, the WAL is first VFS.xSync-ed, then valid content of the
+** WAL is transferred into the database, then the database is VFS.xSync-ed.
+** The VFS.xSync operations serve as write barriers - all writes launched
+** before the xSync must complete before any write that launches after the
+** xSync begins.
+**
+** After each checkpoint, the salt-1 value is incremented and the salt-2
+** value is randomized.  This prevents old and new frames in the WAL from
+** being considered valid at the same time and being checkpointing together
+** following a crash.
+**
+** READER ALGORITHM
+**
+** To read a page from the database (call it page number P), a reader
+** first checks the WAL to see if it contains page P.  If so, then the
+** last valid instance of page P that is a followed by a commit frame
+** or is a commit frame itself becomes the value read.  If the WAL
+** contains no copies of page P that are valid and which are a commit
+** frame or are followed by a commit frame, then page P is read from
+** the database file.
+**
+** To start a read transaction, the reader records the index of the last
+** valid frame in the WAL.  The reader uses this recorded "mxFrame" value
+** for all subsequent read operations.  New transactions can be appended
+** to the WAL, but as long as the reader uses its original mxFrame value
+** and ignores the newly appended content, it will see a consistent snapshot
+** of the database from a single point in time.  This technique allows
+** multiple concurrent readers to view different versions of the database
+** content simultaneously.
+**
+** The reader algorithm in the previous paragraphs works correctly, but 
+** because frames for page P can appear anywhere within the WAL, the
+** reader has to scan the entire WAL looking for page P frames.  If the
+** WAL is large (multiple megabytes is typical) that scan can be slow,
+** and read performance suffers.  To overcome this problem, a separate
+** data structure called the wal-index is maintained to expedite the
+** search for frames of a particular page.
+** 
+** WAL-INDEX FORMAT
+**
+** Conceptually, the wal-index is shared memory, though VFS implementations
+** might choose to implement the wal-index using a mmapped file.  Because
+** the wal-index is shared memory, SQLite does not support journal_mode=WAL 
+** on a network filesystem.  All users of the database must be able to
+** share memory.
+**
+** The wal-index is transient.  After a crash, the wal-index can (and should
+** be) reconstructed from the original WAL file.  In fact, the VFS is required
+** to either truncate or zero the header of the wal-index when the last
+** connection to it closes.  Because the wal-index is transient, it can
+** use an architecture-specific format; it does not have to be cross-platform.
+** Hence, unlike the database and WAL file formats which store all values
+** as big endian, the wal-index can store multi-byte values in the native
+** byte order of the host computer.
+**
+** The purpose of the wal-index is to answer this question quickly:  Given
+** a page number P and a maximum frame index M, return the index of the 
+** last frame in the wal before frame M for page P in the WAL, or return
+** NULL if there are no frames for page P in the WAL prior to M.
+**
+** The wal-index consists of a header region, followed by an one or
+** more index blocks.  
+**
+** The wal-index header contains the total number of frames within the WAL
+** in the mxFrame field.
+**
+** Each index block except for the first contains information on 
+** HASHTABLE_NPAGE frames. The first index block contains information on
+** HASHTABLE_NPAGE_ONE frames. The values of HASHTABLE_NPAGE_ONE and 
+** HASHTABLE_NPAGE are selected so that together the wal-index header and
+** first index block are the same size as all other index blocks in the
+** wal-index.
+**
+** Each index block contains two sections, a page-mapping that contains the
+** database page number associated with each wal frame, and a hash-table 
+** that allows readers to query an index block for a specific page number.
+** The page-mapping is an array of HASHTABLE_NPAGE (or HASHTABLE_NPAGE_ONE
+** for the first index block) 32-bit page numbers. The first entry in the 
+** first index-block contains the database page number corresponding to the
+** first frame in the WAL file. The first entry in the second index block
+** in the WAL file corresponds to the (HASHTABLE_NPAGE_ONE+1)th frame in
+** the log, and so on.
+**
+** The last index block in a wal-index usually contains less than the full
+** complement of HASHTABLE_NPAGE (or HASHTABLE_NPAGE_ONE) page-numbers,
+** depending on the contents of the WAL file. This does not change the
+** allocated size of the page-mapping array - the page-mapping array merely
+** contains unused entries.
+**
+** Even without using the hash table, the last frame for page P
+** can be found by scanning the page-mapping sections of each index block
+** starting with the last index block and moving toward the first, and
+** within each index block, starting at the end and moving toward the
+** beginning.  The first entry that equals P corresponds to the frame
+** holding the content for that page.
+**
+** The hash table consists of HASHTABLE_NSLOT 16-bit unsigned integers.
+** HASHTABLE_NSLOT = 2*HASHTABLE_NPAGE, and there is one entry in the
+** hash table for each page number in the mapping section, so the hash 
+** table is never more than half full.  The expected number of collisions 
+** prior to finding a match is 1.  Each entry of the hash table is an
+** 1-based index of an entry in the mapping section of the same
+** index block.   Let K be the 1-based index of the largest entry in
+** the mapping section.  (For index blocks other than the last, K will
+** always be exactly HASHTABLE_NPAGE (4096) and for the last index block
+** K will be (mxFrame%HASHTABLE_NPAGE).)  Unused slots of the hash table
+** contain a value of 0.
+**
+** To look for page P in the hash table, first compute a hash iKey on
+** P as follows:
+**
+**      iKey = (P * 383) % HASHTABLE_NSLOT
+**
+** Then start scanning entries of the hash table, starting with iKey
+** (wrapping around to the beginning when the end of the hash table is
+** reached) until an unused hash slot is found. Let the first unused slot
+** be at index iUnused.  (iUnused might be less than iKey if there was
+** wrap-around.) Because the hash table is never more than half full,
+** the search is guaranteed to eventually hit an unused entry.  Let 
+** iMax be the value between iKey and iUnused, closest to iUnused,
+** where aHash[iMax]==P.  If there is no iMax entry (if there exists
+** no hash slot such that aHash[i]==p) then page P is not in the
+** current index block.  Otherwise the iMax-th mapping entry of the
+** current index block corresponds to the last entry that references 
+** page P.
+**
+** A hash search begins with the last index block and moves toward the
+** first index block, looking for entries corresponding to page P.  On
+** average, only two or three slots in each index block need to be
+** examined in order to either find the last entry for page P, or to
+** establish that no such entry exists in the block.  Each index block
+** holds over 4000 entries.  So two or three index blocks are sufficient
+** to cover a typical 10 megabyte WAL file, assuming 1K pages.  8 or 10
+** comparisons (on average) suffice to either locate a frame in the
+** WAL or to establish that the frame does not exist in the WAL.  This
+** is much faster than scanning the entire 10MB WAL.
+**
+** Note that entries are added in order of increasing K.  Hence, one
+** reader might be using some value K0 and a second reader that started
+** at a later time (after additional transactions were added to the WAL
+** and to the wal-index) might be using a different value K1, where K1>K0.
+** Both readers can use the same hash table and mapping section to get
+** the correct result.  There may be entries in the hash table with
+** K>K0 but to the first reader, those entries will appear to be unused
+** slots in the hash table and so the first reader will get an answer as
+** if no values greater than K0 had ever been inserted into the hash table
+** in the first place - which is what reader one wants.  Meanwhile, the
+** second reader using K1 will see additional values that were inserted
+** later, which is exactly what reader two wants.  
+**
+** When a rollback occurs, the value of K is decreased. Hash table entries
+** that correspond to frames greater than the new K value are removed
+** from the hash table at this point.
+*/
+#ifndef SQLITE_OMIT_WAL
+
+
+/*
+** Trace output macros
+*/
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3WalTrace = 0;
+# define WALTRACE(X)  if(sqlite3WalTrace) sqlite3DebugPrintf X
+#else
+# define WALTRACE(X)
+#endif
+
+/*
+** The maximum (and only) versions of the wal and wal-index formats
+** that may be interpreted by this version of SQLite.
+**
+** If a client begins recovering a WAL file and finds that (a) the checksum
+** values in the wal-header are correct and (b) the version field is not
+** WAL_MAX_VERSION, recovery fails and SQLite returns SQLITE_CANTOPEN.
+**
+** Similarly, if a client successfully reads a wal-index header (i.e. the 
+** checksum test is successful) and finds that the version field is not
+** WALINDEX_MAX_VERSION, then no read-transaction is opened and SQLite
+** returns SQLITE_CANTOPEN.
+*/
+#define WAL_MAX_VERSION      3007000
+#define WALINDEX_MAX_VERSION 3007000
+
+/*
+** Indices of various locking bytes.   WAL_NREADER is the number
+** of available reader locks and should be at least 3.
+*/
+#define WAL_WRITE_LOCK         0
+#define WAL_ALL_BUT_WRITE      1
+#define WAL_CKPT_LOCK          1
+#define WAL_RECOVER_LOCK       2
+#define WAL_READ_LOCK(I)       (3+(I))
+#define WAL_NREADER            (SQLITE_SHM_NLOCK-3)
+
+
+/* Object declarations */
+typedef struct WalIndexHdr WalIndexHdr;
+typedef struct WalIterator WalIterator;
+typedef struct WalCkptInfo WalCkptInfo;
+
+
+/*
+** The following object holds a copy of the wal-index header content.
+**
+** The actual header in the wal-index consists of two copies of this
+** object.
+**
+** The szPage value can be any power of 2 between 512 and 32768, inclusive.
+** Or it can be 1 to represent a 65536-byte page.  The latter case was
+** added in 3.7.1 when support for 64K pages was added.  
+*/
+struct WalIndexHdr {
+  u32 iVersion;                   /* Wal-index version */
+  u32 unused;                     /* Unused (padding) field */
+  u32 iChange;                    /* Counter incremented each transaction */
+  u8 isInit;                      /* 1 when initialized */
+  u8 bigEndCksum;                 /* True if checksums in WAL are big-endian */
+  u16 szPage;                     /* Database page size in bytes. 1==64K */
+  u32 mxFrame;                    /* Index of last valid frame in the WAL */
+  u32 nPage;                      /* Size of database in pages */
+  u32 aFrameCksum[2];             /* Checksum of last frame in log */
+  u32 aSalt[2];                   /* Two salt values copied from WAL header */
+  u32 aCksum[2];                  /* Checksum over all prior fields */
+};
+
+/*
+** A copy of the following object occurs in the wal-index immediately
+** following the second copy of the WalIndexHdr.  This object stores
+** information used by checkpoint.
+**
+** nBackfill is the number of frames in the WAL that have been written
+** back into the database. (We call the act of moving content from WAL to
+** database "backfilling".)  The nBackfill number is never greater than
+** WalIndexHdr.mxFrame.  nBackfill can only be increased by threads
+** holding the WAL_CKPT_LOCK lock (which includes a recovery thread).
+** However, a WAL_WRITE_LOCK thread can move the value of nBackfill from
+** mxFrame back to zero when the WAL is reset.
+**
+** There is one entry in aReadMark[] for each reader lock.  If a reader
+** holds read-lock K, then the value in aReadMark[K] is no greater than
+** the mxFrame for that reader.  The value READMARK_NOT_USED (0xffffffff)
+** for any aReadMark[] means that entry is unused.  aReadMark[0] is 
+** a special case; its value is never used and it exists as a place-holder
+** to avoid having to offset aReadMark[] indexs by one.  Readers holding
+** WAL_READ_LOCK(0) always ignore the entire WAL and read all content
+** directly from the database.
+**
+** The value of aReadMark[K] may only be changed by a thread that
+** is holding an exclusive lock on WAL_READ_LOCK(K).  Thus, the value of
+** aReadMark[K] cannot changed while there is a reader is using that mark
+** since the reader will be holding a shared lock on WAL_READ_LOCK(K).
+**
+** The checkpointer may only transfer frames from WAL to database where
+** the frame numbers are less than or equal to every aReadMark[] that is
+** in use (that is, every aReadMark[j] for which there is a corresponding
+** WAL_READ_LOCK(j)).  New readers (usually) pick the aReadMark[] with the
+** largest value and will increase an unused aReadMark[] to mxFrame if there
+** is not already an aReadMark[] equal to mxFrame.  The exception to the
+** previous sentence is when nBackfill equals mxFrame (meaning that everything
+** in the WAL has been backfilled into the database) then new readers
+** will choose aReadMark[0] which has value 0 and hence such reader will
+** get all their all content directly from the database file and ignore 
+** the WAL.
+**
+** Writers normally append new frames to the end of the WAL.  However,
+** if nBackfill equals mxFrame (meaning that all WAL content has been
+** written back into the database) and if no readers are using the WAL
+** (in other words, if there are no WAL_READ_LOCK(i) where i>0) then
+** the writer will first "reset" the WAL back to the beginning and start
+** writing new content beginning at frame 1.
+**
+** We assume that 32-bit loads are atomic and so no locks are needed in
+** order to read from any aReadMark[] entries.
+*/
+struct WalCkptInfo {
+  u32 nBackfill;                  /* Number of WAL frames backfilled into DB */
+  u32 aReadMark[WAL_NREADER];     /* Reader marks */
+};
+#define READMARK_NOT_USED  0xffffffff
+
+
+/* A block of WALINDEX_LOCK_RESERVED bytes beginning at
+** WALINDEX_LOCK_OFFSET is reserved for locks. Since some systems
+** only support mandatory file-locks, we do not read or write data
+** from the region of the file on which locks are applied.
+*/
+#define WALINDEX_LOCK_OFFSET   (sizeof(WalIndexHdr)*2 + sizeof(WalCkptInfo))
+#define WALINDEX_LOCK_RESERVED 16
+#define WALINDEX_HDR_SIZE      (WALINDEX_LOCK_OFFSET+WALINDEX_LOCK_RESERVED)
+
+/* Size of header before each frame in wal */
+#define WAL_FRAME_HDRSIZE 24
+
+/* Size of write ahead log header, including checksum. */
+/* #define WAL_HDRSIZE 24 */
+#define WAL_HDRSIZE 32
+
+/* WAL magic value. Either this value, or the same value with the least
+** significant bit also set (WAL_MAGIC | 0x00000001) is stored in 32-bit
+** big-endian format in the first 4 bytes of a WAL file.
+**
+** If the LSB is set, then the checksums for each frame within the WAL
+** file are calculated by treating all data as an array of 32-bit 
+** big-endian words. Otherwise, they are calculated by interpreting 
+** all data as 32-bit little-endian words.
+*/
+#define WAL_MAGIC 0x377f0682
+
+/*
+** Return the offset of frame iFrame in the write-ahead log file, 
+** assuming a database page size of szPage bytes. The offset returned
+** is to the start of the write-ahead log frame-header.
+*/
+#define walFrameOffset(iFrame, szPage) (                               \
+  WAL_HDRSIZE + ((iFrame)-1)*(i64)((szPage)+WAL_FRAME_HDRSIZE)         \
+)
+
+/*
+** An open write-ahead log file is represented by an instance of the
+** following object.
+*/
+struct Wal {
+  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
+  sqlite3_file *pDbFd;       /* File handle for the database file */
+  sqlite3_file *pWalFd;      /* File handle for WAL file */
+  u32 iCallback;             /* Value to pass to log callback (or 0) */
+  i64 mxWalSize;             /* Truncate WAL to this size upon reset */
+  int nWiData;               /* Size of array apWiData */
+  int szFirstBlock;          /* Size of first block written to WAL file */
+  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
+  u32 szPage;                /* Database page size */
+  i16 readLock;              /* Which read lock is being held.  -1 for none */
+  u8 syncFlags;              /* Flags to use to sync header writes */
+  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
+  u8 writeLock;              /* True if in a write transaction */
+  u8 ckptLock;               /* True if holding a checkpoint lock */
+  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
+  u8 truncateOnCommit;       /* True to truncate WAL file on commit */
+  u8 syncHeader;             /* Fsync the WAL header if true */
+  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
+  WalIndexHdr hdr;           /* Wal-index header for current transaction */
+  const char *zWalName;      /* Name of WAL file */
+  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
+#ifdef SQLITE_DEBUG
+  u8 lockError;              /* True if a locking error has occurred */
+#endif
+};
+
+/*
+** Candidate values for Wal.exclusiveMode.
+*/
+#define WAL_NORMAL_MODE     0
+#define WAL_EXCLUSIVE_MODE  1     
+#define WAL_HEAPMEMORY_MODE 2
+
+/*
+** Possible values for WAL.readOnly
+*/
+#define WAL_RDWR        0    /* Normal read/write connection */
+#define WAL_RDONLY      1    /* The WAL file is readonly */
+#define WAL_SHM_RDONLY  2    /* The SHM file is readonly */
+
+/*
+** Each page of the wal-index mapping contains a hash-table made up of
+** an array of HASHTABLE_NSLOT elements of the following type.
+*/
+typedef u16 ht_slot;
+
+/*
+** This structure is used to implement an iterator that loops through
+** all frames in the WAL in database page order. Where two or more frames
+** correspond to the same database page, the iterator visits only the 
+** frame most recently written to the WAL (in other words, the frame with
+** the largest index).
+**
+** The internals of this structure are only accessed by:
+**
+**   walIteratorInit() - Create a new iterator,
+**   walIteratorNext() - Step an iterator,
+**   walIteratorFree() - Free an iterator.
+**
+** This functionality is used by the checkpoint code (see walCheckpoint()).
+*/
+struct WalIterator {
+  int iPrior;                     /* Last result returned from the iterator */
+  int nSegment;                   /* Number of entries in aSegment[] */
+  struct WalSegment {
+    int iNext;                    /* Next slot in aIndex[] not yet returned */
+    ht_slot *aIndex;              /* i0, i1, i2... such that aPgno[iN] ascend */
+    u32 *aPgno;                   /* Array of page numbers. */
+    int nEntry;                   /* Nr. of entries in aPgno[] and aIndex[] */
+    int iZero;                    /* Frame number associated with aPgno[0] */
+  } aSegment[1];                  /* One for every 32KB page in the wal-index */
+};
+
+/*
+** Define the parameters of the hash tables in the wal-index file. There
+** is a hash-table following every HASHTABLE_NPAGE page numbers in the
+** wal-index.
+**
+** Changing any of these constants will alter the wal-index format and
+** create incompatibilities.
+*/
+#define HASHTABLE_NPAGE      4096                 /* Must be power of 2 */
+#define HASHTABLE_HASH_1     383                  /* Should be prime */
+#define HASHTABLE_NSLOT      (HASHTABLE_NPAGE*2)  /* Must be a power of 2 */
+
+/* 
+** The block of page numbers associated with the first hash-table in a
+** wal-index is smaller than usual. This is so that there is a complete
+** hash-table on each aligned 32KB page of the wal-index.
+*/
+#define HASHTABLE_NPAGE_ONE  (HASHTABLE_NPAGE - (WALINDEX_HDR_SIZE/sizeof(u32)))
+
+/* The wal-index is divided into pages of WALINDEX_PGSZ bytes each. */
+#define WALINDEX_PGSZ   (                                         \
+    sizeof(ht_slot)*HASHTABLE_NSLOT + HASHTABLE_NPAGE*sizeof(u32) \
+)
+
+/*
+** Obtain a pointer to the iPage'th page of the wal-index. The wal-index
+** is broken into pages of WALINDEX_PGSZ bytes. Wal-index pages are
+** numbered from zero.
+**
+** If this call is successful, *ppPage is set to point to the wal-index
+** page and SQLITE_OK is returned. If an error (an OOM or VFS error) occurs,
+** then an SQLite error code is returned and *ppPage is set to 0.
+*/
+static int walIndexPage(Wal *pWal, int iPage, volatile u32 **ppPage){
+  int rc = SQLITE_OK;
+
+  /* Enlarge the pWal->apWiData[] array if required */
+  if( pWal->nWiData<=iPage ){
+    int nByte = sizeof(u32*)*(iPage+1);
+    volatile u32 **apNew;
+    apNew = (volatile u32 **)sqlite3_realloc((void *)pWal->apWiData, nByte);
+    if( !apNew ){
+      *ppPage = 0;
+      return SQLITE_NOMEM;
+    }
+    memset((void*)&apNew[pWal->nWiData], 0,
+           sizeof(u32*)*(iPage+1-pWal->nWiData));
+    pWal->apWiData = apNew;
+    pWal->nWiData = iPage+1;
+  }
+
+  /* Request a pointer to the required page from the VFS */
+  if( pWal->apWiData[iPage]==0 ){
+    if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE ){
+      pWal->apWiData[iPage] = (u32 volatile *)sqlite3MallocZero(WALINDEX_PGSZ);
+      if( !pWal->apWiData[iPage] ) rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3OsShmMap(pWal->pDbFd, iPage, WALINDEX_PGSZ, 
+          pWal->writeLock, (void volatile **)&pWal->apWiData[iPage]
+      );
+      if( rc==SQLITE_READONLY ){
+        pWal->readOnly |= WAL_SHM_RDONLY;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  *ppPage = pWal->apWiData[iPage];
+  assert( iPage==0 || *ppPage || rc!=SQLITE_OK );
+  return rc;
+}
+
+/*
+** Return a pointer to the WalCkptInfo structure in the wal-index.
+*/
+static volatile WalCkptInfo *walCkptInfo(Wal *pWal){
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+  return (volatile WalCkptInfo*)&(pWal->apWiData[0][sizeof(WalIndexHdr)/2]);
+}
+
+/*
+** Return a pointer to the WalIndexHdr structure in the wal-index.
+*/
+static volatile WalIndexHdr *walIndexHdr(Wal *pWal){
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+  return (volatile WalIndexHdr*)pWal->apWiData[0];
+}
+
+/*
+** The argument to this macro must be of type u32. On a little-endian
+** architecture, it returns the u32 value that results from interpreting
+** the 4 bytes as a big-endian value. On a big-endian architecture, it
+** returns the value that would be produced by intepreting the 4 bytes
+** of the input value as a little-endian integer.
+*/
+#define BYTESWAP32(x) ( \
+    (((x)&0x000000FF)<<24) + (((x)&0x0000FF00)<<8)  \
+  + (((x)&0x00FF0000)>>8)  + (((x)&0xFF000000)>>24) \
+)
+
+/*
+** Generate or extend an 8 byte checksum based on the data in 
+** array aByte[] and the initial values of aIn[0] and aIn[1] (or
+** initial values of 0 and 0 if aIn==NULL).
+**
+** The checksum is written back into aOut[] before returning.
+**
+** nByte must be a positive multiple of 8.
+*/
+static void walChecksumBytes(
+  int nativeCksum, /* True for native byte-order, false for non-native */
+  u8 *a,           /* Content to be checksummed */
+  int nByte,       /* Bytes of content in a[].  Must be a multiple of 8. */
+  const u32 *aIn,  /* Initial checksum value input */
+  u32 *aOut        /* OUT: Final checksum value output */
+){
+  u32 s1, s2;
+  u32 *aData = (u32 *)a;
+  u32 *aEnd = (u32 *)&a[nByte];
+
+  if( aIn ){
+    s1 = aIn[0];
+    s2 = aIn[1];
+  }else{
+    s1 = s2 = 0;
+  }
+
+  assert( nByte>=8 );
+  assert( (nByte&0x00000007)==0 );
+
+  if( nativeCksum ){
+    do {
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+    }while( aData<aEnd );
+  }else{
+    do {
+      s1 += BYTESWAP32(aData[0]) + s2;
+      s2 += BYTESWAP32(aData[1]) + s1;
+      aData += 2;
+    }while( aData<aEnd );
+  }
+
+  aOut[0] = s1;
+  aOut[1] = s2;
+}
+
+static void walShmBarrier(Wal *pWal){
+  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
+    sqlite3OsShmBarrier(pWal->pDbFd);
+  }
+}
+
+/*
+** Write the header information in pWal->hdr into the wal-index.
+**
+** The checksum on pWal->hdr is updated before it is written.
+*/
+static void walIndexWriteHdr(Wal *pWal){
+  volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
+  const int nCksum = offsetof(WalIndexHdr, aCksum);
+
+  assert( pWal->writeLock );
+  pWal->hdr.isInit = 1;
+  pWal->hdr.iVersion = WALINDEX_MAX_VERSION;
+  walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
+  memcpy((void *)&aHdr[1], (void *)&pWal->hdr, sizeof(WalIndexHdr));
+  walShmBarrier(pWal);
+  memcpy((void *)&aHdr[0], (void *)&pWal->hdr, sizeof(WalIndexHdr));
+}
+
+/*
+** This function encodes a single frame header and writes it to a buffer
+** supplied by the caller. A frame-header is made up of a series of 
+** 4-byte big-endian integers, as follows:
+**
+**     0: Page number.
+**     4: For commit records, the size of the database image in pages 
+**        after the commit. For all other records, zero.
+**     8: Salt-1 (copied from the wal-header)
+**    12: Salt-2 (copied from the wal-header)
+**    16: Checksum-1.
+**    20: Checksum-2.
+*/
+static void walEncodeFrame(
+  Wal *pWal,                      /* The write-ahead log */
+  u32 iPage,                      /* Database page number for frame */
+  u32 nTruncate,                  /* New db size (or 0 for non-commit frames) */
+  u8 *aData,                      /* Pointer to page data */
+  u8 *aFrame                      /* OUT: Write encoded frame here */
+){
+  int nativeCksum;                /* True for native byte-order checksums */
+  u32 *aCksum = pWal->hdr.aFrameCksum;
+  assert( WAL_FRAME_HDRSIZE==24 );
+  sqlite3Put4byte(&aFrame[0], iPage);
+  sqlite3Put4byte(&aFrame[4], nTruncate);
+  memcpy(&aFrame[8], pWal->hdr.aSalt, 8);
+
+  nativeCksum = (pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN);
+  walChecksumBytes(nativeCksum, aFrame, 8, aCksum, aCksum);
+  walChecksumBytes(nativeCksum, aData, pWal->szPage, aCksum, aCksum);
+
+  sqlite3Put4byte(&aFrame[16], aCksum[0]);
+  sqlite3Put4byte(&aFrame[20], aCksum[1]);
+}
+
+/*
+** Check to see if the frame with header in aFrame[] and content
+** in aData[] is valid.  If it is a valid frame, fill *piPage and
+** *pnTruncate and return true.  Return if the frame is not valid.
+*/
+static int walDecodeFrame(
+  Wal *pWal,                      /* The write-ahead log */
+  u32 *piPage,                    /* OUT: Database page number for frame */
+  u32 *pnTruncate,                /* OUT: New db size (or 0 if not commit) */
+  u8 *aData,                      /* Pointer to page data (for checksum) */
+  u8 *aFrame                      /* Frame data */
+){
+  int nativeCksum;                /* True for native byte-order checksums */
+  u32 *aCksum = pWal->hdr.aFrameCksum;
+  u32 pgno;                       /* Page number of the frame */
+  assert( WAL_FRAME_HDRSIZE==24 );
+
+  /* A frame is only valid if the salt values in the frame-header
+  ** match the salt values in the wal-header. 
+  */
+  if( memcmp(&pWal->hdr.aSalt, &aFrame[8], 8)!=0 ){
+    return 0;
+  }
+
+  /* A frame is only valid if the page number is creater than zero.
+  */
+  pgno = sqlite3Get4byte(&aFrame[0]);
+  if( pgno==0 ){
+    return 0;
+  }
+
+  /* A frame is only valid if a checksum of the WAL header,
+  ** all prior frams, the first 16 bytes of this frame-header, 
+  ** and the frame-data matches the checksum in the last 8 
+  ** bytes of this frame-header.
+  */
+  nativeCksum = (pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN);
+  walChecksumBytes(nativeCksum, aFrame, 8, aCksum, aCksum);
+  walChecksumBytes(nativeCksum, aData, pWal->szPage, aCksum, aCksum);
+  if( aCksum[0]!=sqlite3Get4byte(&aFrame[16]) 
+   || aCksum[1]!=sqlite3Get4byte(&aFrame[20]) 
+  ){
+    /* Checksum failed. */
+    return 0;
+  }
+
+  /* If we reach this point, the frame is valid.  Return the page number
+  ** and the new database size.
+  */
+  *piPage = pgno;
+  *pnTruncate = sqlite3Get4byte(&aFrame[4]);
+  return 1;
+}
+
+
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+/*
+** Names of locks.  This routine is used to provide debugging output and is not
+** a part of an ordinary build.
+*/
+static const char *walLockName(int lockIdx){
+  if( lockIdx==WAL_WRITE_LOCK ){
+    return "WRITE-LOCK";
+  }else if( lockIdx==WAL_CKPT_LOCK ){
+    return "CKPT-LOCK";
+  }else if( lockIdx==WAL_RECOVER_LOCK ){
+    return "RECOVER-LOCK";
+  }else{
+    static char zName[15];
+    sqlite3_snprintf(sizeof(zName), zName, "READ-LOCK[%d]",
+                     lockIdx-WAL_READ_LOCK(0));
+    return zName;
+  }
+}
+#endif /*defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
+    
+
+/*
+** Set or release locks on the WAL.  Locks are either shared or exclusive.
+** A lock cannot be moved directly between shared and exclusive - it must go
+** through the unlocked state first.
+**
+** In locking_mode=EXCLUSIVE, all of these routines become no-ops.
+*/
+static int walLockShared(Wal *pWal, int lockIdx){
+  int rc;
+  if( pWal->exclusiveMode ) return SQLITE_OK;
+  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
+                        SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
+  WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
+            walLockName(lockIdx), rc ? "failed" : "ok"));
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
+  return rc;
+}
+static void walUnlockShared(Wal *pWal, int lockIdx){
+  if( pWal->exclusiveMode ) return;
+  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
+                         SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED);
+  WALTRACE(("WAL%p: release SHARED-%s\n", pWal, walLockName(lockIdx)));
+}
+static int walLockExclusive(Wal *pWal, int lockIdx, int n){
+  int rc;
+  if( pWal->exclusiveMode ) return SQLITE_OK;
+  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
+                        SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
+  WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
+            walLockName(lockIdx), n, rc ? "failed" : "ok"));
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
+  return rc;
+}
+static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
+  if( pWal->exclusiveMode ) return;
+  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
+                         SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE);
+  WALTRACE(("WAL%p: release EXCLUSIVE-%s cnt=%d\n", pWal,
+             walLockName(lockIdx), n));
+}
+
+/*
+** Compute a hash on a page number.  The resulting hash value must land
+** between 0 and (HASHTABLE_NSLOT-1).  The walHashNext() function advances
+** the hash to the next value in the event of a collision.
+*/
+static int walHash(u32 iPage){
+  assert( iPage>0 );
+  assert( (HASHTABLE_NSLOT & (HASHTABLE_NSLOT-1))==0 );
+  return (iPage*HASHTABLE_HASH_1) & (HASHTABLE_NSLOT-1);
+}
+static int walNextHash(int iPriorHash){
+  return (iPriorHash+1)&(HASHTABLE_NSLOT-1);
+}
+
+/* 
+** Return pointers to the hash table and page number array stored on
+** page iHash of the wal-index. The wal-index is broken into 32KB pages
+** numbered starting from 0.
+**
+** Set output variable *paHash to point to the start of the hash table
+** in the wal-index file. Set *piZero to one less than the frame 
+** number of the first frame indexed by this hash table. If a
+** slot in the hash table is set to N, it refers to frame number 
+** (*piZero+N) in the log.
+**
+** Finally, set *paPgno so that *paPgno[1] is the page number of the
+** first frame indexed by the hash table, frame (*piZero+1).
+*/
+static int walHashGet(
+  Wal *pWal,                      /* WAL handle */
+  int iHash,                      /* Find the iHash'th table */
+  volatile ht_slot **paHash,      /* OUT: Pointer to hash index */
+  volatile u32 **paPgno,          /* OUT: Pointer to page number array */
+  u32 *piZero                     /* OUT: Frame associated with *paPgno[0] */
+){
+  int rc;                         /* Return code */
+  volatile u32 *aPgno;
+
+  rc = walIndexPage(pWal, iHash, &aPgno);
+  assert( rc==SQLITE_OK || iHash>0 );
+
+  if( rc==SQLITE_OK ){
+    u32 iZero;
+    volatile ht_slot *aHash;
+
+    aHash = (volatile ht_slot *)&aPgno[HASHTABLE_NPAGE];
+    if( iHash==0 ){
+      aPgno = &aPgno[WALINDEX_HDR_SIZE/sizeof(u32)];
+      iZero = 0;
+    }else{
+      iZero = HASHTABLE_NPAGE_ONE + (iHash-1)*HASHTABLE_NPAGE;
+    }
+  
+    *paPgno = &aPgno[-1];
+    *paHash = aHash;
+    *piZero = iZero;
+  }
+  return rc;
+}
+
+/*
+** Return the number of the wal-index page that contains the hash-table
+** and page-number array that contain entries corresponding to WAL frame
+** iFrame. The wal-index is broken up into 32KB pages. Wal-index pages 
+** are numbered starting from 0.
+*/
+static int walFramePage(u32 iFrame){
+  int iHash = (iFrame+HASHTABLE_NPAGE-HASHTABLE_NPAGE_ONE-1) / HASHTABLE_NPAGE;
+  assert( (iHash==0 || iFrame>HASHTABLE_NPAGE_ONE)
+       && (iHash>=1 || iFrame<=HASHTABLE_NPAGE_ONE)
+       && (iHash<=1 || iFrame>(HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE))
+       && (iHash>=2 || iFrame<=HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE)
+       && (iHash<=2 || iFrame>(HASHTABLE_NPAGE_ONE+2*HASHTABLE_NPAGE))
+  );
+  return iHash;
+}
+
+/*
+** Return the page number associated with frame iFrame in this WAL.
+*/
+static u32 walFramePgno(Wal *pWal, u32 iFrame){
+  int iHash = walFramePage(iFrame);
+  if( iHash==0 ){
+    return pWal->apWiData[0][WALINDEX_HDR_SIZE/sizeof(u32) + iFrame - 1];
+  }
+  return pWal->apWiData[iHash][(iFrame-1-HASHTABLE_NPAGE_ONE)%HASHTABLE_NPAGE];
+}
+
+/*
+** Remove entries from the hash table that point to WAL slots greater
+** than pWal->hdr.mxFrame.
+**
+** This function is called whenever pWal->hdr.mxFrame is decreased due
+** to a rollback or savepoint.
+**
+** At most only the hash table containing pWal->hdr.mxFrame needs to be
+** updated.  Any later hash tables will be automatically cleared when
+** pWal->hdr.mxFrame advances to the point where those hash tables are
+** actually needed.
+*/
+static void walCleanupHash(Wal *pWal){
+  volatile ht_slot *aHash = 0;    /* Pointer to hash table to clear */
+  volatile u32 *aPgno = 0;        /* Page number array for hash table */
+  u32 iZero = 0;                  /* frame == (aHash[x]+iZero) */
+  int iLimit = 0;                 /* Zero values greater than this */
+  int nByte;                      /* Number of bytes to zero in aPgno[] */
+  int i;                          /* Used to iterate through aHash[] */
+
+  assert( pWal->writeLock );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE-1 );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE+1 );
+
+  if( pWal->hdr.mxFrame==0 ) return;
+
+  /* Obtain pointers to the hash-table and page-number array containing 
+  ** the entry that corresponds to frame pWal->hdr.mxFrame. It is guaranteed
+  ** that the page said hash-table and array reside on is already mapped.
+  */
+  assert( pWal->nWiData>walFramePage(pWal->hdr.mxFrame) );
+  assert( pWal->apWiData[walFramePage(pWal->hdr.mxFrame)] );
+  walHashGet(pWal, walFramePage(pWal->hdr.mxFrame), &aHash, &aPgno, &iZero);
+
+  /* Zero all hash-table entries that correspond to frame numbers greater
+  ** than pWal->hdr.mxFrame.
+  */
+  iLimit = pWal->hdr.mxFrame - iZero;
+  assert( iLimit>0 );
+  for(i=0; i<HASHTABLE_NSLOT; i++){
+    if( aHash[i]>iLimit ){
+      aHash[i] = 0;
+    }
+  }
+  
+  /* Zero the entries in the aPgno array that correspond to frames with
+  ** frame numbers greater than pWal->hdr.mxFrame. 
+  */
+  nByte = (int)((char *)aHash - (char *)&aPgno[iLimit+1]);
+  memset((void *)&aPgno[iLimit+1], 0, nByte);
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  /* Verify that the every entry in the mapping region is still reachable
+  ** via the hash table even after the cleanup.
+  */
+  if( iLimit ){
+    int i;           /* Loop counter */
+    int iKey;        /* Hash key */
+    for(i=1; i<=iLimit; i++){
+      for(iKey=walHash(aPgno[i]); aHash[iKey]; iKey=walNextHash(iKey)){
+        if( aHash[iKey]==i ) break;
+      }
+      assert( aHash[iKey]==i );
+    }
+  }
+#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
+}
+
+
+/*
+** Set an entry in the wal-index that will map database page number
+** pPage into WAL frame iFrame.
+*/
+static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
+  int rc;                         /* Return code */
+  u32 iZero = 0;                  /* One less than frame number of aPgno[1] */
+  volatile u32 *aPgno = 0;        /* Page number array */
+  volatile ht_slot *aHash = 0;    /* Hash table */
+
+  rc = walHashGet(pWal, walFramePage(iFrame), &aHash, &aPgno, &iZero);
+
+  /* Assuming the wal-index file was successfully mapped, populate the
+  ** page number array and hash table entry.
+  */
+  if( rc==SQLITE_OK ){
+    int iKey;                     /* Hash table key */
+    int idx;                      /* Value to write to hash-table slot */
+    int nCollide;                 /* Number of hash collisions */
+
+    idx = iFrame - iZero;
+    assert( idx <= HASHTABLE_NSLOT/2 + 1 );
+    
+    /* If this is the first entry to be added to this hash-table, zero the
+    ** entire hash table and aPgno[] array before proceding. 
+    */
+    if( idx==1 ){
+      int nByte = (int)((u8 *)&aHash[HASHTABLE_NSLOT] - (u8 *)&aPgno[1]);
+      memset((void*)&aPgno[1], 0, nByte);
+    }
+
+    /* If the entry in aPgno[] is already set, then the previous writer
+    ** must have exited unexpectedly in the middle of a transaction (after
+    ** writing one or more dirty pages to the WAL to free up memory). 
+    ** Remove the remnants of that writers uncommitted transaction from 
+    ** the hash-table before writing any new entries.
+    */
+    if( aPgno[idx] ){
+      walCleanupHash(pWal);
+      assert( !aPgno[idx] );
+    }
+
+    /* Write the aPgno[] array entry and the hash-table slot. */
+    nCollide = idx;
+    for(iKey=walHash(iPage); aHash[iKey]; iKey=walNextHash(iKey)){
+      if( (nCollide--)==0 ) return SQLITE_CORRUPT_BKPT;
+    }
+    aPgno[idx] = iPage;
+    aHash[iKey] = (ht_slot)idx;
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+    /* Verify that the number of entries in the hash table exactly equals
+    ** the number of entries in the mapping region.
+    */
+    {
+      int i;           /* Loop counter */
+      int nEntry = 0;  /* Number of entries in the hash table */
+      for(i=0; i<HASHTABLE_NSLOT; i++){ if( aHash[i] ) nEntry++; }
+      assert( nEntry==idx );
+    }
+
+    /* Verify that the every entry in the mapping region is reachable
+    ** via the hash table.  This turns out to be a really, really expensive
+    ** thing to check, so only do this occasionally - not on every
+    ** iteration.
+    */
+    if( (idx&0x3ff)==0 ){
+      int i;           /* Loop counter */
+      for(i=1; i<=idx; i++){
+        for(iKey=walHash(aPgno[i]); aHash[iKey]; iKey=walNextHash(iKey)){
+          if( aHash[iKey]==i ) break;
+        }
+        assert( aHash[iKey]==i );
+      }
+    }
+#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
+  }
+
+
+  return rc;
+}
+
+
+/*
+** Recover the wal-index by reading the write-ahead log file. 
+**
+** This routine first tries to establish an exclusive lock on the
+** wal-index to prevent other threads/processes from doing anything
+** with the WAL or wal-index while recovery is running.  The
+** WAL_RECOVER_LOCK is also held so that other threads will know
+** that this thread is running recovery.  If unable to establish
+** the necessary locks, this routine returns SQLITE_BUSY.
+*/
+static int walIndexRecover(Wal *pWal){
+  int rc;                         /* Return Code */
+  i64 nSize;                      /* Size of log file */
+  u32 aFrameCksum[2] = {0, 0};
+  int iLock;                      /* Lock offset to lock for checkpoint */
+  int nLock;                      /* Number of locks to hold */
+
+  /* Obtain an exclusive lock on all byte in the locking range not already
+  ** locked by the caller. The caller is guaranteed to have locked the
+  ** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte.
+  ** If successful, the same bytes that are locked here are unlocked before
+  ** this function returns.
+  */
+  assert( pWal->ckptLock==1 || pWal->ckptLock==0 );
+  assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 );
+  assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
+  assert( pWal->writeLock );
+  iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock;
+  nLock = SQLITE_SHM_NLOCK - iLock;
+  rc = walLockExclusive(pWal, iLock, nLock);
+  if( rc ){
+    return rc;
+  }
+  WALTRACE(("WAL%p: recovery begin...\n", pWal));
+
+  memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
+
+  rc = sqlite3OsFileSize(pWal->pWalFd, &nSize);
+  if( rc!=SQLITE_OK ){
+    goto recovery_error;
+  }
+
+  if( nSize>WAL_HDRSIZE ){
+    u8 aBuf[WAL_HDRSIZE];         /* Buffer to load WAL header into */
+    u8 *aFrame = 0;               /* Malloc'd buffer to load entire frame */
+    int szFrame;                  /* Number of bytes in buffer aFrame[] */
+    u8 *aData;                    /* Pointer to data part of aFrame buffer */
+    int iFrame;                   /* Index of last frame read */
+    i64 iOffset;                  /* Next offset to read from log file */
+    int szPage;                   /* Page size according to the log */
+    u32 magic;                    /* Magic value read from WAL header */
+    u32 version;                  /* Magic value read from WAL header */
+    int isValid;                  /* True if this frame is valid */
+
+    /* Read in the WAL header. */
+    rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
+    if( rc!=SQLITE_OK ){
+      goto recovery_error;
+    }
+
+    /* If the database page size is not a power of two, or is greater than
+    ** SQLITE_MAX_PAGE_SIZE, conclude that the WAL file contains no valid 
+    ** data. Similarly, if the 'magic' value is invalid, ignore the whole
+    ** WAL file.
+    */
+    magic = sqlite3Get4byte(&aBuf[0]);
+    szPage = sqlite3Get4byte(&aBuf[8]);
+    if( (magic&0xFFFFFFFE)!=WAL_MAGIC 
+     || szPage&(szPage-1) 
+     || szPage>SQLITE_MAX_PAGE_SIZE 
+     || szPage<512 
+    ){
+      goto finished;
+    }
+    pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
+    pWal->szPage = szPage;
+    pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
+    memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);
+
+    /* Verify that the WAL header checksum is correct */
+    walChecksumBytes(pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN, 
+        aBuf, WAL_HDRSIZE-2*4, 0, pWal->hdr.aFrameCksum
+    );
+    if( pWal->hdr.aFrameCksum[0]!=sqlite3Get4byte(&aBuf[24])
+     || pWal->hdr.aFrameCksum[1]!=sqlite3Get4byte(&aBuf[28])
+    ){
+      goto finished;
+    }
+
+    /* Verify that the version number on the WAL format is one that
+    ** are able to understand */
+    version = sqlite3Get4byte(&aBuf[4]);
+    if( version!=WAL_MAX_VERSION ){
+      rc = SQLITE_CANTOPEN_BKPT;
+      goto finished;
+    }
+
+    /* Malloc a buffer to read frames into. */
+    szFrame = szPage + WAL_FRAME_HDRSIZE;
+    aFrame = (u8 *)sqlite3_malloc(szFrame);
+    if( !aFrame ){
+      rc = SQLITE_NOMEM;
+      goto recovery_error;
+    }
+    aData = &aFrame[WAL_FRAME_HDRSIZE];
+
+    /* Read all frames from the log file. */
+    iFrame = 0;
+    for(iOffset=WAL_HDRSIZE; (iOffset+szFrame)<=nSize; iOffset+=szFrame){
+      u32 pgno;                   /* Database page number for frame */
+      u32 nTruncate;              /* dbsize field from frame header */
+
+      /* Read and decode the next log frame. */
+      iFrame++;
+      rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
+      if( rc!=SQLITE_OK ) break;
+      isValid = walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame);
+      if( !isValid ) break;
+      rc = walIndexAppend(pWal, iFrame, pgno);
+      if( rc!=SQLITE_OK ) break;
+
+      /* If nTruncate is non-zero, this is a commit record. */
+      if( nTruncate ){
+        pWal->hdr.mxFrame = iFrame;
+        pWal->hdr.nPage = nTruncate;
+        pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
+        testcase( szPage<=32768 );
+        testcase( szPage>=65536 );
+        aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
+        aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
+      }
+    }
+
+    sqlite3_free(aFrame);
+  }
+
+finished:
+  if( rc==SQLITE_OK ){
+    volatile WalCkptInfo *pInfo;
+    int i;
+    pWal->hdr.aFrameCksum[0] = aFrameCksum[0];
+    pWal->hdr.aFrameCksum[1] = aFrameCksum[1];
+    walIndexWriteHdr(pWal);
+
+    /* Reset the checkpoint-header. This is safe because this thread is 
+    ** currently holding locks that exclude all other readers, writers and
+    ** checkpointers.
+    */
+    pInfo = walCkptInfo(pWal);
+    pInfo->nBackfill = 0;
+    pInfo->aReadMark[0] = 0;
+    for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
+    if( pWal->hdr.mxFrame ) pInfo->aReadMark[1] = pWal->hdr.mxFrame;
+
+    /* If more than one frame was recovered from the log file, report an
+    ** event via sqlite3_log(). This is to help with identifying performance
+    ** problems caused by applications routinely shutting down without
+    ** checkpointing the log file.
+    */
+    if( pWal->hdr.nPage ){
+      sqlite3_log(SQLITE_OK, "Recovered %d frames from WAL file %s",
+          pWal->hdr.nPage, pWal->zWalName
+      );
+    }
+  }
+
+recovery_error:
+  WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
+  walUnlockExclusive(pWal, iLock, nLock);
+  return rc;
+}
+
+/*
+** Close an open wal-index.
+*/
+static void walIndexClose(Wal *pWal, int isDelete){
+  if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE ){
+    int i;
+    for(i=0; i<pWal->nWiData; i++){
+      sqlite3_free((void *)pWal->apWiData[i]);
+      pWal->apWiData[i] = 0;
+    }
+  }else{
+    sqlite3OsShmUnmap(pWal->pDbFd, isDelete);
+  }
+}
+
+/* 
+** Open a connection to the WAL file zWalName. The database file must 
+** already be opened on connection pDbFd. The buffer that zWalName points
+** to must remain valid for the lifetime of the returned Wal* handle.
+**
+** A SHARED lock should be held on the database file when this function
+** is called. The purpose of this SHARED lock is to prevent any other
+** client from unlinking the WAL or wal-index file. If another process
+** were to do this just after this client opened one of these files, the
+** system would be badly broken.
+**
+** If the log file is successfully opened, SQLITE_OK is returned and 
+** *ppWal is set to point to a new WAL handle. If an error occurs,
+** an SQLite error code is returned and *ppWal is left unmodified.
+*/
+SQLITE_PRIVATE int sqlite3WalOpen(
+  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
+  sqlite3_file *pDbFd,            /* The open database file */
+  const char *zWalName,           /* Name of the WAL file */
+  int bNoShm,                     /* True to run in heap-memory mode */
+  i64 mxWalSize,                  /* Truncate WAL to this size on reset */
+  Wal **ppWal                     /* OUT: Allocated Wal handle */
+){
+  int rc;                         /* Return Code */
+  Wal *pRet;                      /* Object to allocate and return */
+  int flags;                      /* Flags passed to OsOpen() */
+
+  assert( zWalName && zWalName[0] );
+  assert( pDbFd );
+
+  /* In the amalgamation, the os_unix.c and os_win.c source files come before
+  ** this source file.  Verify that the #defines of the locking byte offsets
+  ** in os_unix.c and os_win.c agree with the WALINDEX_LOCK_OFFSET value.
+  */
+#ifdef WIN_SHM_BASE
+  assert( WIN_SHM_BASE==WALINDEX_LOCK_OFFSET );
+#endif
+#ifdef UNIX_SHM_BASE
+  assert( UNIX_SHM_BASE==WALINDEX_LOCK_OFFSET );
+#endif
+
+
+  /* Allocate an instance of struct Wal to return. */
+  *ppWal = 0;
+  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile);
+  if( !pRet ){
+    return SQLITE_NOMEM;
+  }
+
+  pRet->pVfs = pVfs;
+  pRet->pWalFd = (sqlite3_file *)&pRet[1];
+  pRet->pDbFd = pDbFd;
+  pRet->readLock = -1;
+  pRet->mxWalSize = mxWalSize;
+  pRet->zWalName = zWalName;
+  pRet->syncHeader = 1;
+  pRet->padToSectorBoundary = 1;
+  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);
+
+  /* Open file handle on the write-ahead log file. */
+  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
+  rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
+  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
+    pRet->readOnly = WAL_RDONLY;
+  }
+
+  if( rc!=SQLITE_OK ){
+    walIndexClose(pRet, 0);
+    sqlite3OsClose(pRet->pWalFd);
+    sqlite3_free(pRet);
+  }else{
+    int iDC = sqlite3OsDeviceCharacteristics(pRet->pWalFd);
+    if( iDC & SQLITE_IOCAP_SEQUENTIAL ){ pRet->syncHeader = 0; }
+    if( iDC & SQLITE_IOCAP_POWERSAFE_OVERWRITE ){
+      pRet->padToSectorBoundary = 0;
+    }
+    *ppWal = pRet;
+    WALTRACE(("WAL%d: opened\n", pRet));
+  }
+  return rc;
+}
+
+/*
+** Change the size to which the WAL file is trucated on each reset.
+*/
+SQLITE_PRIVATE void sqlite3WalLimit(Wal *pWal, i64 iLimit){
+  if( pWal ) pWal->mxWalSize = iLimit;
+}
+
+/*
+** Find the smallest page number out of all pages held in the WAL that
+** has not been returned by any prior invocation of this method on the
+** same WalIterator object.   Write into *piFrame the frame index where
+** that page was last written into the WAL.  Write into *piPage the page
+** number.
+**
+** Return 0 on success.  If there are no pages in the WAL with a page
+** number larger than *piPage, then return 1.
+*/
+static int walIteratorNext(
+  WalIterator *p,               /* Iterator */
+  u32 *piPage,                  /* OUT: The page number of the next page */
+  u32 *piFrame                  /* OUT: Wal frame index of next page */
+){
+  u32 iMin;                     /* Result pgno must be greater than iMin */
+  u32 iRet = 0xFFFFFFFF;        /* 0xffffffff is never a valid page number */
+  int i;                        /* For looping through segments */
+
+  iMin = p->iPrior;
+  assert( iMin<0xffffffff );
+  for(i=p->nSegment-1; i>=0; i--){
+    struct WalSegment *pSegment = &p->aSegment[i];
+    while( pSegment->iNext<pSegment->nEntry ){
+      u32 iPg = pSegment->aPgno[pSegment->aIndex[pSegment->iNext]];
+      if( iPg>iMin ){
+        if( iPg<iRet ){
+          iRet = iPg;
+          *piFrame = pSegment->iZero + pSegment->aIndex[pSegment->iNext];
+        }
+        break;
+      }
+      pSegment->iNext++;
+    }
+  }
+
+  *piPage = p->iPrior = iRet;
+  return (iRet==0xFFFFFFFF);
+}
+
+/*
+** This function merges two sorted lists into a single sorted list.
+**
+** aLeft[] and aRight[] are arrays of indices.  The sort key is
+** aContent[aLeft[]] and aContent[aRight[]].  Upon entry, the following
+** is guaranteed for all J<K:
+**
+**        aContent[aLeft[J]] < aContent[aLeft[K]]
+**        aContent[aRight[J]] < aContent[aRight[K]]
+**
+** This routine overwrites aRight[] with a new (probably longer) sequence
+** of indices such that the aRight[] contains every index that appears in
+** either aLeft[] or the old aRight[] and such that the second condition
+** above is still met.
+**
+** The aContent[aLeft[X]] values will be unique for all X.  And the
+** aContent[aRight[X]] values will be unique too.  But there might be
+** one or more combinations of X and Y such that
+**
+**      aLeft[X]!=aRight[Y]  &&  aContent[aLeft[X]] == aContent[aRight[Y]]
+**
+** When that happens, omit the aLeft[X] and use the aRight[Y] index.
+*/
+static void walMerge(
+  const u32 *aContent,            /* Pages in wal - keys for the sort */
+  ht_slot *aLeft,                 /* IN: Left hand input list */
+  int nLeft,                      /* IN: Elements in array *paLeft */
+  ht_slot **paRight,              /* IN/OUT: Right hand input list */
+  int *pnRight,                   /* IN/OUT: Elements in *paRight */
+  ht_slot *aTmp                   /* Temporary buffer */
+){
+  int iLeft = 0;                  /* Current index in aLeft */
+  int iRight = 0;                 /* Current index in aRight */
+  int iOut = 0;                   /* Current index in output buffer */
+  int nRight = *pnRight;
+  ht_slot *aRight = *paRight;
+
+  assert( nLeft>0 && nRight>0 );
+  while( iRight<nRight || iLeft<nLeft ){
+    ht_slot logpage;
+    Pgno dbpage;
+
+    if( (iLeft<nLeft) 
+     && (iRight>=nRight || aContent[aLeft[iLeft]]<aContent[aRight[iRight]])
+    ){
+      logpage = aLeft[iLeft++];
+    }else{
+      logpage = aRight[iRight++];
+    }
+    dbpage = aContent[logpage];
+
+    aTmp[iOut++] = logpage;
+    if( iLeft<nLeft && aContent[aLeft[iLeft]]==dbpage ) iLeft++;
+
+    assert( iLeft>=nLeft || aContent[aLeft[iLeft]]>dbpage );
+    assert( iRight>=nRight || aContent[aRight[iRight]]>dbpage );
+  }
+
+  *paRight = aLeft;
+  *pnRight = iOut;
+  memcpy(aLeft, aTmp, sizeof(aTmp[0])*iOut);
+}
+
+/*
+** Sort the elements in list aList using aContent[] as the sort key.
+** Remove elements with duplicate keys, preferring to keep the
+** larger aList[] values.
+**
+** The aList[] entries are indices into aContent[].  The values in
+** aList[] are to be sorted so that for all J<K:
+**
+**      aContent[aList[J]] < aContent[aList[K]]
+**
+** For any X and Y such that
+**
+**      aContent[aList[X]] == aContent[aList[Y]]
+**
+** Keep the larger of the two values aList[X] and aList[Y] and discard
+** the smaller.
+*/
+static void walMergesort(
+  const u32 *aContent,            /* Pages in wal */
+  ht_slot *aBuffer,               /* Buffer of at least *pnList items to use */
+  ht_slot *aList,                 /* IN/OUT: List to sort */
+  int *pnList                     /* IN/OUT: Number of elements in aList[] */
+){
+  struct Sublist {
+    int nList;                    /* Number of elements in aList */
+    ht_slot *aList;               /* Pointer to sub-list content */
+  };
+
+  const int nList = *pnList;      /* Size of input list */
+  int nMerge = 0;                 /* Number of elements in list aMerge */
+  ht_slot *aMerge = 0;            /* List to be merged */
+  int iList;                      /* Index into input list */
+  int iSub = 0;                   /* Index into aSub array */
+  struct Sublist aSub[13];        /* Array of sub-lists */
+
+  memset(aSub, 0, sizeof(aSub));
+  assert( nList<=HASHTABLE_NPAGE && nList>0 );
+  assert( HASHTABLE_NPAGE==(1<<(ArraySize(aSub)-1)) );
+
+  for(iList=0; iList<nList; iList++){
+    nMerge = 1;
+    aMerge = &aList[iList];
+    for(iSub=0; iList & (1<<iSub); iSub++){
+      struct Sublist *p = &aSub[iSub];
+      assert( p->aList && p->nList<=(1<<iSub) );
+      assert( p->aList==&aList[iList&~((2<<iSub)-1)] );
+      walMerge(aContent, p->aList, p->nList, &aMerge, &nMerge, aBuffer);
+    }
+    aSub[iSub].aList = aMerge;
+    aSub[iSub].nList = nMerge;
+  }
+
+  for(iSub++; iSub<ArraySize(aSub); iSub++){
+    if( nList & (1<<iSub) ){
+      struct Sublist *p = &aSub[iSub];
+      assert( p->nList<=(1<<iSub) );
+      assert( p->aList==&aList[nList&~((2<<iSub)-1)] );
+      walMerge(aContent, p->aList, p->nList, &aMerge, &nMerge, aBuffer);
+    }
+  }
+  assert( aMerge==aList );
+  *pnList = nMerge;
+
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=1; i<*pnList; i++){
+      assert( aContent[aList[i]] > aContent[aList[i-1]] );
+    }
+  }
+#endif
+}
+
+/* 
+** Free an iterator allocated by walIteratorInit().
+*/
+static void walIteratorFree(WalIterator *p){
+  sqlite3ScratchFree(p);
+}
+
+/*
+** Construct a WalInterator object that can be used to loop over all 
+** pages in the WAL in ascending order. The caller must hold the checkpoint
+** lock.
+**
+** On success, make *pp point to the newly allocated WalInterator object
+** return SQLITE_OK. Otherwise, return an error code. If this routine
+** returns an error, the value of *pp is undefined.
+**
+** The calling routine should invoke walIteratorFree() to destroy the
+** WalIterator object when it has finished with it.
+*/
+static int walIteratorInit(Wal *pWal, WalIterator **pp){
+  WalIterator *p;                 /* Return value */
+  int nSegment;                   /* Number of segments to merge */
+  u32 iLast;                      /* Last frame in log */
+  int nByte;                      /* Number of bytes to allocate */
+  int i;                          /* Iterator variable */
+  ht_slot *aTmp;                  /* Temp space used by merge-sort */
+  int rc = SQLITE_OK;             /* Return Code */
+
+  /* This routine only runs while holding the checkpoint lock. And
+  ** it only runs if there is actually content in the log (mxFrame>0).
+  */
+  assert( pWal->ckptLock && pWal->hdr.mxFrame>0 );
+  iLast = pWal->hdr.mxFrame;
+
+  /* Allocate space for the WalIterator object. */
+  nSegment = walFramePage(iLast) + 1;
+  nByte = sizeof(WalIterator) 
+        + (nSegment-1)*sizeof(struct WalSegment)
+        + iLast*sizeof(ht_slot);
+  p = (WalIterator *)sqlite3ScratchMalloc(nByte);
+  if( !p ){
+    return SQLITE_NOMEM;
+  }
+  memset(p, 0, nByte);
+  p->nSegment = nSegment;
+
+  /* Allocate temporary space used by the merge-sort routine. This block
+  ** of memory will be freed before this function returns.
+  */
+  aTmp = (ht_slot *)sqlite3ScratchMalloc(
+      sizeof(ht_slot) * (iLast>HASHTABLE_NPAGE?HASHTABLE_NPAGE:iLast)
+  );
+  if( !aTmp ){
+    rc = SQLITE_NOMEM;
+  }
+
+  for(i=0; rc==SQLITE_OK && i<nSegment; i++){
+    volatile ht_slot *aHash;
+    u32 iZero;
+    volatile u32 *aPgno;
+
+    rc = walHashGet(pWal, i, &aHash, &aPgno, &iZero);
+    if( rc==SQLITE_OK ){
+      int j;                      /* Counter variable */
+      int nEntry;                 /* Number of entries in this segment */
+      ht_slot *aIndex;            /* Sorted index for this segment */
+
+      aPgno++;
+      if( (i+1)==nSegment ){
+        nEntry = (int)(iLast - iZero);
+      }else{
+        nEntry = (int)((u32*)aHash - (u32*)aPgno);
+      }
+      aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[iZero];
+      iZero++;
+  
+      for(j=0; j<nEntry; j++){
+        aIndex[j] = (ht_slot)j;
+      }
+      walMergesort((u32 *)aPgno, aTmp, aIndex, &nEntry);
+      p->aSegment[i].iZero = iZero;
+      p->aSegment[i].nEntry = nEntry;
+      p->aSegment[i].aIndex = aIndex;
+      p->aSegment[i].aPgno = (u32 *)aPgno;
+    }
+  }
+  sqlite3ScratchFree(aTmp);
+
+  if( rc!=SQLITE_OK ){
+    walIteratorFree(p);
+  }
+  *pp = p;
+  return rc;
+}
+
+/*
+** Attempt to obtain the exclusive WAL lock defined by parameters lockIdx and
+** n. If the attempt fails and parameter xBusy is not NULL, then it is a
+** busy-handler function. Invoke it and retry the lock until either the
+** lock is successfully obtained or the busy-handler returns 0.
+*/
+static int walBusyLock(
+  Wal *pWal,                      /* WAL connection */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int lockIdx,                    /* Offset of first byte to lock */
+  int n                           /* Number of bytes to lock */
+){
+  int rc;
+  do {
+    rc = walLockExclusive(pWal, lockIdx, n);
+  }while( xBusy && rc==SQLITE_BUSY && xBusy(pBusyArg) );
+  return rc;
+}
+
+/*
+** The cache of the wal-index header must be valid to call this function.
+** Return the page-size in bytes used by the database.
+*/
+static int walPagesize(Wal *pWal){
+  return (pWal->hdr.szPage&0xfe00) + ((pWal->hdr.szPage&0x0001)<<16);
+}
+
+/*
+** Copy as much content as we can from the WAL back into the database file
+** in response to an sqlite3_wal_checkpoint() request or the equivalent.
+**
+** The amount of information copies from WAL to database might be limited
+** by active readers.  This routine will never overwrite a database page
+** that a concurrent reader might be using.
+**
+** All I/O barrier operations (a.k.a fsyncs) occur in this routine when
+** SQLite is in WAL-mode in synchronous=NORMAL.  That means that if 
+** checkpoints are always run by a background thread or background 
+** process, foreground threads will never block on a lengthy fsync call.
+**
+** Fsync is called on the WAL before writing content out of the WAL and
+** into the database.  This ensures that if the new content is persistent
+** in the WAL and can be recovered following a power-loss or hard reset.
+**
+** Fsync is also called on the database file if (and only if) the entire
+** WAL content is copied into the database file.  This second fsync makes
+** it safe to delete the WAL since the new content will persist in the
+** database file.
+**
+** This routine uses and updates the nBackfill field of the wal-index header.
+** This is the only routine tha will increase the value of nBackfill.  
+** (A WAL reset or recovery will revert nBackfill to zero, but not increase
+** its value.)
+**
+** The caller must be holding sufficient locks to ensure that no other
+** checkpoint is running (in any other thread or process) at the same
+** time.
+*/
+static int walCheckpoint(
+  Wal *pWal,                      /* Wal connection */
+  int eMode,                      /* One of PASSIVE, FULL or RESTART */
+  int (*xBusyCall)(void*),        /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags for OsSync() (or 0) */
+  u8 *zBuf                        /* Temporary buffer to use */
+){
+  int rc;                         /* Return code */
+  int szPage;                     /* Database page-size */
+  WalIterator *pIter = 0;         /* Wal iterator context */
+  u32 iDbpage = 0;                /* Next database page to write */
+  u32 iFrame = 0;                 /* Wal frame containing data for iDbpage */
+  u32 mxSafeFrame;                /* Max frame that can be backfilled */
+  u32 mxPage;                     /* Max database page to write */
+  int i;                          /* Loop counter */
+  volatile WalCkptInfo *pInfo;    /* The checkpoint status information */
+  int (*xBusy)(void*) = 0;        /* Function to call when waiting for locks */
+
+  szPage = walPagesize(pWal);
+  testcase( szPage<=32768 );
+  testcase( szPage>=65536 );
+  pInfo = walCkptInfo(pWal);
+  if( pInfo->nBackfill>=pWal->hdr.mxFrame ) return SQLITE_OK;
+
+  /* Allocate the iterator */
+  rc = walIteratorInit(pWal, &pIter);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  assert( pIter );
+
+  if( eMode!=SQLITE_CHECKPOINT_PASSIVE ) xBusy = xBusyCall;
+
+  /* Compute in mxSafeFrame the index of the last frame of the WAL that is
+  ** safe to write into the database.  Frames beyond mxSafeFrame might
+  ** overwrite database pages that are in use by active readers and thus
+  ** cannot be backfilled from the WAL.
+  */
+  mxSafeFrame = pWal->hdr.mxFrame;
+  mxPage = pWal->hdr.nPage;
+  for(i=1; i<WAL_NREADER; i++){
+    u32 y = pInfo->aReadMark[i];
+    if( mxSafeFrame>y ){
+      assert( y<=pWal->hdr.mxFrame );
+      rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
+      if( rc==SQLITE_OK ){
+        pInfo->aReadMark[i] = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
+        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+      }else if( rc==SQLITE_BUSY ){
+        mxSafeFrame = y;
+        xBusy = 0;
+      }else{
+        goto walcheckpoint_out;
+      }
+    }
+  }
+
+  if( pInfo->nBackfill<mxSafeFrame
+   && (rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(0), 1))==SQLITE_OK
+  ){
+    i64 nSize;                    /* Current size of database file */
+    u32 nBackfill = pInfo->nBackfill;
+
+    /* Sync the WAL to disk */
+    if( sync_flags ){
+      rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
+    }
+
+    /* If the database file may grow as a result of this checkpoint, hint
+    ** about the eventual size of the db file to the VFS layer. 
+    */
+    if( rc==SQLITE_OK ){
+      i64 nReq = ((i64)mxPage * szPage);
+      rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
+      if( rc==SQLITE_OK && nSize<nReq ){
+        sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT, &nReq);
+      }
+    }
+
+    /* Iterate through the contents of the WAL, copying data to the db file. */
+    while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
+      i64 iOffset;
+      assert( walFramePgno(pWal, iFrame)==iDbpage );
+      if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ) continue;
+      iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
+      /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
+      rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
+      if( rc!=SQLITE_OK ) break;
+      iOffset = (iDbpage-1)*(i64)szPage;
+      testcase( IS_BIG_INT(iOffset) );
+      rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
+      if( rc!=SQLITE_OK ) break;
+    }
+
+    /* If work was actually accomplished... */
+    if( rc==SQLITE_OK ){
+      if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
+        i64 szDb = pWal->hdr.nPage*(i64)szPage;
+        testcase( IS_BIG_INT(szDb) );
+        rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
+        if( rc==SQLITE_OK && sync_flags ){
+          rc = sqlite3OsSync(pWal->pDbFd, sync_flags);
+        }
+      }
+      if( rc==SQLITE_OK ){
+        pInfo->nBackfill = mxSafeFrame;
+      }
+    }
+
+    /* Release the reader lock held while backfilling */
+    walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);
+  }
+
+  if( rc==SQLITE_BUSY ){
+    /* Reset the return code so as not to report a checkpoint failure
+    ** just because there are active readers.  */
+    rc = SQLITE_OK;
+  }
+
+  /* If this is an SQLITE_CHECKPOINT_RESTART operation, and the entire wal
+  ** file has been copied into the database file, then block until all
+  ** readers have finished using the wal file. This ensures that the next
+  ** process to write to the database restarts the wal file.
+  */
+  if( rc==SQLITE_OK && eMode!=SQLITE_CHECKPOINT_PASSIVE ){
+    assert( pWal->writeLock );
+    if( pInfo->nBackfill<pWal->hdr.mxFrame ){
+      rc = SQLITE_BUSY;
+    }else if( eMode==SQLITE_CHECKPOINT_RESTART ){
+      assert( mxSafeFrame==pWal->hdr.mxFrame );
+      rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1);
+      if( rc==SQLITE_OK ){
+        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      }
+    }
+  }
+
+ walcheckpoint_out:
+  walIteratorFree(pIter);
+  return rc;
+}
+
+/*
+** If the WAL file is currently larger than nMax bytes in size, truncate
+** it to exactly nMax bytes. If an error occurs while doing so, ignore it.
+*/
+static void walLimitSize(Wal *pWal, i64 nMax){
+  i64 sz;
+  int rx;
+  sqlite3BeginBenignMalloc();
+  rx = sqlite3OsFileSize(pWal->pWalFd, &sz);
+  if( rx==SQLITE_OK && (sz > nMax ) ){
+    rx = sqlite3OsTruncate(pWal->pWalFd, nMax);
+  }
+  sqlite3EndBenignMalloc();
+  if( rx ){
+    sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
+  }
+}
+
+/*
+** Close a connection to a log file.
+*/
+SQLITE_PRIVATE int sqlite3WalClose(
+  Wal *pWal,                      /* Wal to close */
+  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
+  int nBuf,
+  u8 *zBuf                        /* Buffer of at least nBuf bytes */
+){
+  int rc = SQLITE_OK;
+  if( pWal ){
+    int isDelete = 0;             /* True to unlink wal and wal-index files */
+
+    /* If an EXCLUSIVE lock can be obtained on the database file (using the
+    ** ordinary, rollback-mode locking methods, this guarantees that the
+    ** connection associated with this log file is the only connection to
+    ** the database. In this case checkpoint the database and unlink both
+    ** the wal and wal-index files.
+    **
+    ** The EXCLUSIVE lock is not released before returning.
+    */
+    rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE);
+    if( rc==SQLITE_OK ){
+      if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
+        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
+      }
+      rc = sqlite3WalCheckpoint(
+          pWal, SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
+      );
+      if( rc==SQLITE_OK ){
+        int bPersist = -1;
+        sqlite3OsFileControlHint(
+            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
+        );
+        if( bPersist!=1 ){
+          /* Try to delete the WAL file if the checkpoint completed and
+          ** fsyned (rc==SQLITE_OK) and if we are not in persistent-wal
+          ** mode (!bPersist) */
+          isDelete = 1;
+        }else if( pWal->mxWalSize>=0 ){
+          /* Try to truncate the WAL file to zero bytes if the checkpoint
+          ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
+          ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
+          ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate
+          ** to zero bytes as truncating to the journal_size_limit might
+          ** leave a corrupt WAL file on disk. */
+          walLimitSize(pWal, 0);
+        }
+      }
+    }
+
+    walIndexClose(pWal, isDelete);
+    sqlite3OsClose(pWal->pWalFd);
+    if( isDelete ){
+      sqlite3BeginBenignMalloc();
+      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
+      sqlite3EndBenignMalloc();
+    }
+    WALTRACE(("WAL%p: closed\n", pWal));
+    sqlite3_free((void *)pWal->apWiData);
+    sqlite3_free(pWal);
+  }
+  return rc;
+}
+
+/*
+** Try to read the wal-index header.  Return 0 on success and 1 if
+** there is a problem.
+**
+** The wal-index is in shared memory.  Another thread or process might
+** be writing the header at the same time this procedure is trying to
+** read it, which might result in inconsistency.  A dirty read is detected
+** by verifying that both copies of the header are the same and also by
+** a checksum on the header.
+**
+** If and only if the read is consistent and the header is different from
+** pWal->hdr, then pWal->hdr is updated to the content of the new header
+** and *pChanged is set to 1.
+**
+** If the checksum cannot be verified return non-zero. If the header
+** is read successfully and the checksum verified, return zero.
+*/
+static int walIndexTryHdr(Wal *pWal, int *pChanged){
+  u32 aCksum[2];                  /* Checksum on the header content */
+  WalIndexHdr h1, h2;             /* Two copies of the header content */
+  WalIndexHdr volatile *aHdr;     /* Header in shared memory */
+
+  /* The first page of the wal-index must be mapped at this point. */
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+
+  /* Read the header. This might happen concurrently with a write to the
+  ** same area of shared memory on a different CPU in a SMP,
+  ** meaning it is possible that an inconsistent snapshot is read
+  ** from the file. If this happens, return non-zero.
+  **
+  ** There are two copies of the header at the beginning of the wal-index.
+  ** When reading, read [0] first then [1].  Writes are in the reverse order.
+  ** Memory barriers are used to prevent the compiler or the hardware from
+  ** reordering the reads and writes.
+  */
+  aHdr = walIndexHdr(pWal);
+  memcpy(&h1, (void *)&aHdr[0], sizeof(h1));
+  walShmBarrier(pWal);
+  memcpy(&h2, (void *)&aHdr[1], sizeof(h2));
+
+  if( memcmp(&h1, &h2, sizeof(h1))!=0 ){
+    return 1;   /* Dirty read */
+  }  
+  if( h1.isInit==0 ){
+    return 1;   /* Malformed header - probably all zeros */
+  }
+  walChecksumBytes(1, (u8*)&h1, sizeof(h1)-sizeof(h1.aCksum), 0, aCksum);
+  if( aCksum[0]!=h1.aCksum[0] || aCksum[1]!=h1.aCksum[1] ){
+    return 1;   /* Checksum does not match */
+  }
+
+  if( memcmp(&pWal->hdr, &h1, sizeof(WalIndexHdr)) ){
+    *pChanged = 1;
+    memcpy(&pWal->hdr, &h1, sizeof(WalIndexHdr));
+    pWal->szPage = (pWal->hdr.szPage&0xfe00) + ((pWal->hdr.szPage&0x0001)<<16);
+    testcase( pWal->szPage<=32768 );
+    testcase( pWal->szPage>=65536 );
+  }
+
+  /* The header was successfully read. Return zero. */
+  return 0;
+}
+
+/*
+** Read the wal-index header from the wal-index and into pWal->hdr.
+** If the wal-header appears to be corrupt, try to reconstruct the
+** wal-index from the WAL before returning.
+**
+** Set *pChanged to 1 if the wal-index header value in pWal->hdr is
+** changed by this opertion.  If pWal->hdr is unchanged, set *pChanged
+** to 0.
+**
+** If the wal-index header is successfully read, return SQLITE_OK. 
+** Otherwise an SQLite error code.
+*/
+static int walIndexReadHdr(Wal *pWal, int *pChanged){
+  int rc;                         /* Return code */
+  int badHdr;                     /* True if a header read failed */
+  volatile u32 *page0;            /* Chunk of wal-index containing header */
+
+  /* Ensure that page 0 of the wal-index (the page that contains the 
+  ** wal-index header) is mapped. Return early if an error occurs here.
+  */
+  assert( pChanged );
+  rc = walIndexPage(pWal, 0, &page0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  };
+  assert( page0 || pWal->writeLock==0 );
+
+  /* If the first page of the wal-index has been mapped, try to read the
+  ** wal-index header immediately, without holding any lock. This usually
+  ** works, but may fail if the wal-index header is corrupt or currently 
+  ** being modified by another thread or process.
+  */
+  badHdr = (page0 ? walIndexTryHdr(pWal, pChanged) : 1);
+
+  /* If the first attempt failed, it might have been due to a race
+  ** with a writer.  So get a WRITE lock and try again.
+  */
+  assert( badHdr==0 || pWal->writeLock==0 );
+  if( badHdr ){
+    if( pWal->readOnly & WAL_SHM_RDONLY ){
+      if( SQLITE_OK==(rc = walLockShared(pWal, WAL_WRITE_LOCK)) ){
+        walUnlockShared(pWal, WAL_WRITE_LOCK);
+        rc = SQLITE_READONLY_RECOVERY;
+      }
+    }else if( SQLITE_OK==(rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1)) ){
+      pWal->writeLock = 1;
+      if( SQLITE_OK==(rc = walIndexPage(pWal, 0, &page0)) ){
+        badHdr = walIndexTryHdr(pWal, pChanged);
+        if( badHdr ){
+          /* If the wal-index header is still malformed even while holding
+          ** a WRITE lock, it can only mean that the header is corrupted and
+          ** needs to be reconstructed.  So run recovery to do exactly that.
+          */
+          rc = walIndexRecover(pWal);
+          *pChanged = 1;
+        }
+      }
+      pWal->writeLock = 0;
+      walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    }
+  }
+
+  /* If the header is read successfully, check the version number to make
+  ** sure the wal-index was not constructed with some future format that
+  ** this version of SQLite cannot understand.
+  */
+  if( badHdr==0 && pWal->hdr.iVersion!=WALINDEX_MAX_VERSION ){
+    rc = SQLITE_CANTOPEN_BKPT;
+  }
+
+  return rc;
+}
+
+/*
+** This is the value that walTryBeginRead returns when it needs to
+** be retried.
+*/
+#define WAL_RETRY  (-1)
+
+/*
+** Attempt to start a read transaction.  This might fail due to a race or
+** other transient condition.  When that happens, it returns WAL_RETRY to
+** indicate to the caller that it is safe to retry immediately.
+**
+** On success return SQLITE_OK.  On a permanent failure (such an
+** I/O error or an SQLITE_BUSY because another process is running
+** recovery) return a positive error code.
+**
+** The useWal parameter is true to force the use of the WAL and disable
+** the case where the WAL is bypassed because it has been completely
+** checkpointed.  If useWal==0 then this routine calls walIndexReadHdr() 
+** to make a copy of the wal-index header into pWal->hdr.  If the 
+** wal-index header has changed, *pChanged is set to 1 (as an indication 
+** to the caller that the local paget cache is obsolete and needs to be 
+** flushed.)  When useWal==1, the wal-index header is assumed to already
+** be loaded and the pChanged parameter is unused.
+**
+** The caller must set the cnt parameter to the number of prior calls to
+** this routine during the current read attempt that returned WAL_RETRY.
+** This routine will start taking more aggressive measures to clear the
+** race conditions after multiple WAL_RETRY returns, and after an excessive
+** number of errors will ultimately return SQLITE_PROTOCOL.  The
+** SQLITE_PROTOCOL return indicates that some other process has gone rogue
+** and is not honoring the locking protocol.  There is a vanishingly small
+** chance that SQLITE_PROTOCOL could be returned because of a run of really
+** bad luck when there is lots of contention for the wal-index, but that
+** possibility is so small that it can be safely neglected, we believe.
+**
+** On success, this routine obtains a read lock on 
+** WAL_READ_LOCK(pWal->readLock).  The pWal->readLock integer is
+** in the range 0 <= pWal->readLock < WAL_NREADER.  If pWal->readLock==(-1)
+** that means the Wal does not hold any read lock.  The reader must not
+** access any database page that is modified by a WAL frame up to and
+** including frame number aReadMark[pWal->readLock].  The reader will
+** use WAL frames up to and including pWal->hdr.mxFrame if pWal->readLock>0
+** Or if pWal->readLock==0, then the reader will ignore the WAL
+** completely and get all content directly from the database file.
+** If the useWal parameter is 1 then the WAL will never be ignored and
+** this routine will always set pWal->readLock>0 on success.
+** When the read transaction is completed, the caller must release the
+** lock on WAL_READ_LOCK(pWal->readLock) and set pWal->readLock to -1.
+**
+** This routine uses the nBackfill and aReadMark[] fields of the header
+** to select a particular WAL_READ_LOCK() that strives to let the
+** checkpoint process do as much work as possible.  This routine might
+** update values of the aReadMark[] array in the header, but if it does
+** so it takes care to hold an exclusive lock on the corresponding
+** WAL_READ_LOCK() while changing values.
+*/
+static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){
+  volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */
+  u32 mxReadMark;                 /* Largest aReadMark[] value */
+  int mxI;                        /* Index of largest aReadMark[] value */
+  int i;                          /* Loop counter */
+  int rc = SQLITE_OK;             /* Return code  */
+
+  assert( pWal->readLock<0 );     /* Not currently locked */
+
+  /* Take steps to avoid spinning forever if there is a protocol error.
+  **
+  ** Circumstances that cause a RETRY should only last for the briefest
+  ** instances of time.  No I/O or other system calls are done while the
+  ** locks are held, so the locks should not be held for very long. But 
+  ** if we are unlucky, another process that is holding a lock might get
+  ** paged out or take a page-fault that is time-consuming to resolve, 
+  ** during the few nanoseconds that it is holding the lock.  In that case,
+  ** it might take longer than normal for the lock to free.
+  **
+  ** After 5 RETRYs, we begin calling sqlite3OsSleep().  The first few
+  ** calls to sqlite3OsSleep() have a delay of 1 microsecond.  Really this
+  ** is more of a scheduler yield than an actual delay.  But on the 10th
+  ** an subsequent retries, the delays start becoming longer and longer, 
+  ** so that on the 100th (and last) RETRY we delay for 21 milliseconds.
+  ** The total delay time before giving up is less than 1 second.
+  */
+  if( cnt>5 ){
+    int nDelay = 1;                      /* Pause time in microseconds */
+    if( cnt>100 ){
+      VVA_ONLY( pWal->lockError = 1; )
+      return SQLITE_PROTOCOL;
+    }
+    if( cnt>=10 ) nDelay = (cnt-9)*238;  /* Max delay 21ms. Total delay 996ms */
+    sqlite3OsSleep(pWal->pVfs, nDelay);
+  }
+
+  if( !useWal ){
+    rc = walIndexReadHdr(pWal, pChanged);
+    if( rc==SQLITE_BUSY ){
+      /* If there is not a recovery running in another thread or process
+      ** then convert BUSY errors to WAL_RETRY.  If recovery is known to
+      ** be running, convert BUSY to BUSY_RECOVERY.  There is a race here
+      ** which might cause WAL_RETRY to be returned even if BUSY_RECOVERY
+      ** would be technically correct.  But the race is benign since with
+      ** WAL_RETRY this routine will be called again and will probably be
+      ** right on the second iteration.
+      */
+      if( pWal->apWiData[0]==0 ){
+        /* This branch is taken when the xShmMap() method returns SQLITE_BUSY.
+        ** We assume this is a transient condition, so return WAL_RETRY. The
+        ** xShmMap() implementation used by the default unix and win32 VFS 
+        ** modules may return SQLITE_BUSY due to a race condition in the 
+        ** code that determines whether or not the shared-memory region 
+        ** must be zeroed before the requested page is returned.
+        */
+        rc = WAL_RETRY;
+      }else if( SQLITE_OK==(rc = walLockShared(pWal, WAL_RECOVER_LOCK)) ){
+        walUnlockShared(pWal, WAL_RECOVER_LOCK);
+        rc = WAL_RETRY;
+      }else if( rc==SQLITE_BUSY ){
+        rc = SQLITE_BUSY_RECOVERY;
+      }
+    }
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+  }
+
+  pInfo = walCkptInfo(pWal);
+  if( !useWal && pInfo->nBackfill==pWal->hdr.mxFrame ){
+    /* The WAL has been completely backfilled (or it is empty).
+    ** and can be safely ignored.
+    */
+    rc = walLockShared(pWal, WAL_READ_LOCK(0));
+    walShmBarrier(pWal);
+    if( rc==SQLITE_OK ){
+      if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr)) ){
+        /* It is not safe to allow the reader to continue here if frames
+        ** may have been appended to the log before READ_LOCK(0) was obtained.
+        ** When holding READ_LOCK(0), the reader ignores the entire log file,
+        ** which implies that the database file contains a trustworthy
+        ** snapshoT. Since holding READ_LOCK(0) prevents a checkpoint from
+        ** happening, this is usually correct.
+        **
+        ** However, if frames have been appended to the log (or if the log 
+        ** is wrapped and written for that matter) before the READ_LOCK(0)
+        ** is obtained, that is not necessarily true. A checkpointer may
+        ** have started to backfill the appended frames but crashed before
+        ** it finished. Leaving a corrupt image in the database file.
+        */
+        walUnlockShared(pWal, WAL_READ_LOCK(0));
+        return WAL_RETRY;
+      }
+      pWal->readLock = 0;
+      return SQLITE_OK;
+    }else if( rc!=SQLITE_BUSY ){
+      return rc;
+    }
+  }
+
+  /* If we get this far, it means that the reader will want to use
+  ** the WAL to get at content from recent commits.  The job now is
+  ** to select one of the aReadMark[] entries that is closest to
+  ** but not exceeding pWal->hdr.mxFrame and lock that entry.
+  */
+  mxReadMark = 0;
+  mxI = 0;
+  for(i=1; i<WAL_NREADER; i++){
+    u32 thisMark = pInfo->aReadMark[i];
+    if( mxReadMark<=thisMark && thisMark<=pWal->hdr.mxFrame ){
+      assert( thisMark!=READMARK_NOT_USED );
+      mxReadMark = thisMark;
+      mxI = i;
+    }
+  }
+  /* There was once an "if" here. The extra "{" is to preserve indentation. */
+  {
+    if( (pWal->readOnly & WAL_SHM_RDONLY)==0
+     && (mxReadMark<pWal->hdr.mxFrame || mxI==0)
+    ){
+      for(i=1; i<WAL_NREADER; i++){
+        rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
+        if( rc==SQLITE_OK ){
+          mxReadMark = pInfo->aReadMark[i] = pWal->hdr.mxFrame;
+          mxI = i;
+          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+          break;
+        }else if( rc!=SQLITE_BUSY ){
+          return rc;
+        }
+      }
+    }
+    if( mxI==0 ){
+      assert( rc==SQLITE_BUSY || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
+      return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTLOCK;
+    }
+
+    rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
+    if( rc ){
+      return rc==SQLITE_BUSY ? WAL_RETRY : rc;
+    }
+    /* Now that the read-lock has been obtained, check that neither the
+    ** value in the aReadMark[] array or the contents of the wal-index
+    ** header have changed.
+    **
+    ** It is necessary to check that the wal-index header did not change
+    ** between the time it was read and when the shared-lock was obtained
+    ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
+    ** that the log file may have been wrapped by a writer, or that frames
+    ** that occur later in the log than pWal->hdr.mxFrame may have been
+    ** copied into the database by a checkpointer. If either of these things
+    ** happened, then reading the database with the current value of
+    ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
+    ** instead.
+    **
+    ** This does not guarantee that the copy of the wal-index header is up to
+    ** date before proceeding. That would not be possible without somehow
+    ** blocking writers. It only guarantees that a dangerous checkpoint or 
+    ** log-wrap (either of which would require an exclusive lock on
+    ** WAL_READ_LOCK(mxI)) has not occurred since the snapshot was valid.
+    */
+    walShmBarrier(pWal);
+    if( pInfo->aReadMark[mxI]!=mxReadMark
+     || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
+    ){
+      walUnlockShared(pWal, WAL_READ_LOCK(mxI));
+      return WAL_RETRY;
+    }else{
+      assert( mxReadMark<=pWal->hdr.mxFrame );
+      pWal->readLock = (i16)mxI;
+    }
+  }
+  return rc;
+}
+
+/*
+** Begin a read transaction on the database.
+**
+** This routine used to be called sqlite3OpenSnapshot() and with good reason:
+** it takes a snapshot of the state of the WAL and wal-index for the current
+** instant in time.  The current thread will continue to use this snapshot.
+** Other threads might append new content to the WAL and wal-index but
+** that extra content is ignored by the current thread.
+**
+** If the database contents have changes since the previous read
+** transaction, then *pChanged is set to 1 before returning.  The
+** Pager layer will use this to know that is cache is stale and
+** needs to be flushed.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginReadTransaction(Wal *pWal, int *pChanged){
+  int rc;                         /* Return code */
+  int cnt = 0;                    /* Number of TryBeginRead attempts */
+
+  do{
+    rc = walTryBeginRead(pWal, pChanged, 0, ++cnt);
+  }while( rc==WAL_RETRY );
+  testcase( (rc&0xff)==SQLITE_BUSY );
+  testcase( (rc&0xff)==SQLITE_IOERR );
+  testcase( rc==SQLITE_PROTOCOL );
+  testcase( rc==SQLITE_OK );
+  return rc;
+}
+
+/*
+** Finish with a read transaction.  All this does is release the
+** read-lock.
+*/
+SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal){
+  sqlite3WalEndWriteTransaction(pWal);
+  if( pWal->readLock>=0 ){
+    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
+    pWal->readLock = -1;
+  }
+}
+
+/*
+** Read a page from the WAL, if it is present in the WAL and if the 
+** current read transaction is configured to use the WAL.  
+**
+** The *pInWal is set to 1 if the requested page is in the WAL and
+** has been loaded.  Or *pInWal is set to 0 if the page was not in 
+** the WAL and needs to be read out of the database.
+*/
+SQLITE_PRIVATE int sqlite3WalRead(
+  Wal *pWal,                      /* WAL handle */
+  Pgno pgno,                      /* Database page number to read data for */
+  int *pInWal,                    /* OUT: True if data is read from WAL */
+  int nOut,                       /* Size of buffer pOut in bytes */
+  u8 *pOut                        /* Buffer to write page data to */
+){
+  u32 iRead = 0;                  /* If !=0, WAL frame to return data from */
+  u32 iLast = pWal->hdr.mxFrame;  /* Last page in WAL for this reader */
+  int iHash;                      /* Used to loop through N hash tables */
+
+  /* This routine is only be called from within a read transaction. */
+  assert( pWal->readLock>=0 || pWal->lockError );
+
+  /* If the "last page" field of the wal-index header snapshot is 0, then
+  ** no data will be read from the wal under any circumstances. Return early
+  ** in this case as an optimization.  Likewise, if pWal->readLock==0, 
+  ** then the WAL is ignored by the reader so return early, as if the 
+  ** WAL were empty.
+  */
+  if( iLast==0 || pWal->readLock==0 ){
+    *pInWal = 0;
+    return SQLITE_OK;
+  }
+
+  /* Search the hash table or tables for an entry matching page number
+  ** pgno. Each iteration of the following for() loop searches one
+  ** hash table (each hash table indexes up to HASHTABLE_NPAGE frames).
+  **
+  ** This code might run concurrently to the code in walIndexAppend()
+  ** that adds entries to the wal-index (and possibly to this hash 
+  ** table). This means the value just read from the hash 
+  ** slot (aHash[iKey]) may have been added before or after the 
+  ** current read transaction was opened. Values added after the
+  ** read transaction was opened may have been written incorrectly -
+  ** i.e. these slots may contain garbage data. However, we assume
+  ** that any slots written before the current read transaction was
+  ** opened remain unmodified.
+  **
+  ** For the reasons above, the if(...) condition featured in the inner
+  ** loop of the following block is more stringent that would be required 
+  ** if we had exclusive access to the hash-table:
+  **
+  **   (aPgno[iFrame]==pgno): 
+  **     This condition filters out normal hash-table collisions.
+  **
+  **   (iFrame<=iLast): 
+  **     This condition filters out entries that were added to the hash
+  **     table after the current read-transaction had started.
+  */
+  for(iHash=walFramePage(iLast); iHash>=0 && iRead==0; iHash--){
+    volatile ht_slot *aHash;      /* Pointer to hash table */
+    volatile u32 *aPgno;          /* Pointer to array of page numbers */
+    u32 iZero;                    /* Frame number corresponding to aPgno[0] */
+    int iKey;                     /* Hash slot index */
+    int nCollide;                 /* Number of hash collisions remaining */
+    int rc;                       /* Error code */
+
+    rc = walHashGet(pWal, iHash, &aHash, &aPgno, &iZero);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    nCollide = HASHTABLE_NSLOT;
+    for(iKey=walHash(pgno); aHash[iKey]; iKey=walNextHash(iKey)){
+      u32 iFrame = aHash[iKey] + iZero;
+      if( iFrame<=iLast && aPgno[aHash[iKey]]==pgno ){
+        /* assert( iFrame>iRead ); -- not true if there is corruption */
+        iRead = iFrame;
+      }
+      if( (nCollide--)==0 ){
+        return SQLITE_CORRUPT_BKPT;
+      }
+    }
+  }
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  /* If expensive assert() statements are available, do a linear search
+  ** of the wal-index file content. Make sure the results agree with the
+  ** result obtained using the hash indexes above.  */
+  {
+    u32 iRead2 = 0;
+    u32 iTest;
+    for(iTest=iLast; iTest>0; iTest--){
+      if( walFramePgno(pWal, iTest)==pgno ){
+        iRead2 = iTest;
+        break;
+      }
+    }
+    assert( iRead==iRead2 );
+  }
+#endif
+
+  /* If iRead is non-zero, then it is the log frame number that contains the
+  ** required page. Read and return data from the log file.
+  */
+  if( iRead ){
+    int sz;
+    i64 iOffset;
+    sz = pWal->hdr.szPage;
+    sz = (sz&0xfe00) + ((sz&0x0001)<<16);
+    testcase( sz<=32768 );
+    testcase( sz>=65536 );
+    iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
+    *pInWal = 1;
+    /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
+    return sqlite3OsRead(pWal->pWalFd, pOut, (nOut>sz ? sz : nOut), iOffset);
+  }
+
+  *pInWal = 0;
+  return SQLITE_OK;
+}
+
+
+/* 
+** Return the size of the database in pages (or zero, if unknown).
+*/
+SQLITE_PRIVATE Pgno sqlite3WalDbsize(Wal *pWal){
+  if( pWal && ALWAYS(pWal->readLock>=0) ){
+    return pWal->hdr.nPage;
+  }
+  return 0;
+}
+
+
+/* 
+** This function starts a write transaction on the WAL.
+**
+** A read transaction must have already been started by a prior call
+** to sqlite3WalBeginReadTransaction().
+**
+** If another thread or process has written into the database since
+** the read transaction was started, then it is not possible for this
+** thread to write as doing so would cause a fork.  So this routine
+** returns SQLITE_BUSY in that case and no write transaction is started.
+**
+** There can only be a single writer active at a time.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginWriteTransaction(Wal *pWal){
+  int rc;
+
+  /* Cannot start a write transaction without first holding a read
+  ** transaction. */
+  assert( pWal->readLock>=0 );
+
+  if( pWal->readOnly ){
+    return SQLITE_READONLY;
+  }
+
+  /* Only one writer allowed at a time.  Get the write lock.  Return
+  ** SQLITE_BUSY if unable.
+  */
+  rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1);
+  if( rc ){
+    return rc;
+  }
+  pWal->writeLock = 1;
+
+  /* If another connection has written to the database file since the
+  ** time the read transaction on this connection was started, then
+  ** the write is disallowed.
+  */
+  if( memcmp(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr))!=0 ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+    rc = SQLITE_BUSY;
+  }
+
+  return rc;
+}
+
+/*
+** End a write transaction.  The commit has already been done.  This
+** routine merely releases the lock.
+*/
+SQLITE_PRIVATE int sqlite3WalEndWriteTransaction(Wal *pWal){
+  if( pWal->writeLock ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+    pWal->truncateOnCommit = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** If any data has been written (but not committed) to the log file, this
+** function moves the write-pointer back to the start of the transaction.
+**
+** Additionally, the callback function is invoked for each frame written
+** to the WAL since the start of the transaction. If the callback returns
+** other than SQLITE_OK, it is not invoked again and the error code is
+** returned to the caller.
+**
+** Otherwise, if the callback function does not return an error, this
+** function returns SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
+  int rc = SQLITE_OK;
+  if( ALWAYS(pWal->writeLock) ){
+    Pgno iMax = pWal->hdr.mxFrame;
+    Pgno iFrame;
+  
+    /* Restore the clients cache of the wal-index header to the state it
+    ** was in before the client began writing to the database. 
+    */
+    memcpy(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr));
+
+    for(iFrame=pWal->hdr.mxFrame+1; 
+        ALWAYS(rc==SQLITE_OK) && iFrame<=iMax; 
+        iFrame++
+    ){
+      /* This call cannot fail. Unless the page for which the page number
+      ** is passed as the second argument is (a) in the cache and 
+      ** (b) has an outstanding reference, then xUndo is either a no-op
+      ** (if (a) is false) or simply expels the page from the cache (if (b)
+      ** is false).
+      **
+      ** If the upper layer is doing a rollback, it is guaranteed that there
+      ** are no outstanding references to any page other than page 1. And
+      ** page 1 is never written to the log until the transaction is
+      ** committed. As a result, the call to xUndo may not fail.
+      */
+      assert( walFramePgno(pWal, iFrame)!=1 );
+      rc = xUndo(pUndoCtx, walFramePgno(pWal, iFrame));
+    }
+    walCleanupHash(pWal);
+  }
+  assert( rc==SQLITE_OK );
+  return rc;
+}
+
+/* 
+** Argument aWalData must point to an array of WAL_SAVEPOINT_NDATA u32 
+** values. This function populates the array with values required to 
+** "rollback" the write position of the WAL handle back to the current 
+** point in the event of a savepoint rollback (via WalSavepointUndo()).
+*/
+SQLITE_PRIVATE void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData){
+  assert( pWal->writeLock );
+  aWalData[0] = pWal->hdr.mxFrame;
+  aWalData[1] = pWal->hdr.aFrameCksum[0];
+  aWalData[2] = pWal->hdr.aFrameCksum[1];
+  aWalData[3] = pWal->nCkpt;
+}
+
+/* 
+** Move the write position of the WAL back to the point identified by
+** the values in the aWalData[] array. aWalData must point to an array
+** of WAL_SAVEPOINT_NDATA u32 values that has been previously populated
+** by a call to WalSavepoint().
+*/
+SQLITE_PRIVATE int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
+  int rc = SQLITE_OK;
+
+  assert( pWal->writeLock );
+  assert( aWalData[3]!=pWal->nCkpt || aWalData[0]<=pWal->hdr.mxFrame );
+
+  if( aWalData[3]!=pWal->nCkpt ){
+    /* This savepoint was opened immediately after the write-transaction
+    ** was started. Right after that, the writer decided to wrap around
+    ** to the start of the log. Update the savepoint values to match.
+    */
+    aWalData[0] = 0;
+    aWalData[3] = pWal->nCkpt;
+  }
+
+  if( aWalData[0]<pWal->hdr.mxFrame ){
+    pWal->hdr.mxFrame = aWalData[0];
+    pWal->hdr.aFrameCksum[0] = aWalData[1];
+    pWal->hdr.aFrameCksum[1] = aWalData[2];
+    walCleanupHash(pWal);
+  }
+
+  return rc;
+}
+
+
+/*
+** This function is called just before writing a set of frames to the log
+** file (see sqlite3WalFrames()). It checks to see if, instead of appending
+** to the current log file, it is possible to overwrite the start of the
+** existing log file with the new frames (i.e. "reset" the log). If so,
+** it sets pWal->hdr.mxFrame to 0. Otherwise, pWal->hdr.mxFrame is left
+** unchanged.
+**
+** SQLITE_OK is returned if no error is encountered (regardless of whether
+** or not pWal->hdr.mxFrame is modified). An SQLite error code is returned
+** if an error occurs.
+*/
+static int walRestartLog(Wal *pWal){
+  int rc = SQLITE_OK;
+  int cnt;
+
+  if( pWal->readLock==0 ){
+    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+    assert( pInfo->nBackfill==pWal->hdr.mxFrame );
+    if( pInfo->nBackfill>0 ){
+      u32 salt1;
+      sqlite3_randomness(4, &salt1);
+      rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      if( rc==SQLITE_OK ){
+        /* If all readers are using WAL_READ_LOCK(0) (in other words if no
+        ** readers are currently using the WAL), then the transactions
+        ** frames will overwrite the start of the existing log. Update the
+        ** wal-index header to reflect this.
+        **
+        ** In theory it would be Ok to update the cache of the header only
+        ** at this point. But updating the actual wal-index header is also
+        ** safe and means there is no special case for sqlite3WalUndo()
+        ** to handle if this transaction is rolled back.
+        */
+        int i;                    /* Loop counter */
+        u32 *aSalt = pWal->hdr.aSalt;       /* Big-endian salt values */
+
+        pWal->nCkpt++;
+        pWal->hdr.mxFrame = 0;
+        sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
+        aSalt[1] = salt1;
+        walIndexWriteHdr(pWal);
+        pInfo->nBackfill = 0;
+        pInfo->aReadMark[1] = 0;
+        for(i=2; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
+        assert( pInfo->aReadMark[0]==0 );
+        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      }else if( rc!=SQLITE_BUSY ){
+        return rc;
+      }
+    }
+    walUnlockShared(pWal, WAL_READ_LOCK(0));
+    pWal->readLock = -1;
+    cnt = 0;
+    do{
+      int notUsed;
+      rc = walTryBeginRead(pWal, &notUsed, 1, ++cnt);
+    }while( rc==WAL_RETRY );
+    assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
+    testcase( (rc&0xff)==SQLITE_IOERR );
+    testcase( rc==SQLITE_PROTOCOL );
+    testcase( rc==SQLITE_OK );
+  }
+  return rc;
+}
+
+/*
+** Information about the current state of the WAL file and where
+** the next fsync should occur - passed from sqlite3WalFrames() into
+** walWriteToLog().
+*/
+typedef struct WalWriter {
+  Wal *pWal;                   /* The complete WAL information */
+  sqlite3_file *pFd;           /* The WAL file to which we write */
+  sqlite3_int64 iSyncPoint;    /* Fsync at this offset */
+  int syncFlags;               /* Flags for the fsync */
+  int szPage;                  /* Size of one page */
+} WalWriter;
+
+/*
+** Write iAmt bytes of content into the WAL file beginning at iOffset.
+** Do a sync when crossing the p->iSyncPoint boundary.
+**
+** In other words, if iSyncPoint is in between iOffset and iOffset+iAmt,
+** first write the part before iSyncPoint, then sync, then write the
+** rest.
+*/
+static int walWriteToLog(
+  WalWriter *p,              /* WAL to write to */
+  void *pContent,            /* Content to be written */
+  int iAmt,                  /* Number of bytes to write */
+  sqlite3_int64 iOffset      /* Start writing at this offset */
+){
+  int rc;
+  if( iOffset<p->iSyncPoint && iOffset+iAmt>=p->iSyncPoint ){
+    int iFirstAmt = (int)(p->iSyncPoint - iOffset);
+    rc = sqlite3OsWrite(p->pFd, pContent, iFirstAmt, iOffset);
+    if( rc ) return rc;
+    iOffset += iFirstAmt;
+    iAmt -= iFirstAmt;
+    pContent = (void*)(iFirstAmt + (char*)pContent);
+    assert( p->syncFlags & (SQLITE_SYNC_NORMAL|SQLITE_SYNC_FULL) );
+    rc = sqlite3OsSync(p->pFd, p->syncFlags);
+    if( iAmt==0 || rc ) return rc;
+  }
+  rc = sqlite3OsWrite(p->pFd, pContent, iAmt, iOffset);
+  return rc;
+}
+
+/*
+** Write out a single frame of the WAL
+*/
+static int walWriteOneFrame(
+  WalWriter *p,               /* Where to write the frame */
+  PgHdr *pPage,               /* The page of the frame to be written */
+  int nTruncate,              /* The commit flag.  Usually 0.  >0 for commit */
+  sqlite3_int64 iOffset       /* Byte offset at which to write */
+){
+  int rc;                         /* Result code from subfunctions */
+  void *pData;                    /* Data actually written */
+  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-header in */
+#if defined(SQLITE_HAS_CODEC)
+  if( (pData = sqlite3PagerCodec(pPage))==0 ) return SQLITE_NOMEM;
+#else
+  pData = pPage->pData;
+#endif
+  walEncodeFrame(p->pWal, pPage->pgno, nTruncate, pData, aFrame);
+  rc = walWriteToLog(p, aFrame, sizeof(aFrame), iOffset);
+  if( rc ) return rc;
+  /* Write the page data */
+  rc = walWriteToLog(p, pData, p->szPage, iOffset+sizeof(aFrame));
+  return rc;
+}
+
+/* 
+** Write a set of frames to the log. The caller must hold the write-lock
+** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
+*/
+SQLITE_PRIVATE int sqlite3WalFrames(
+  Wal *pWal,                      /* Wal handle to write to */
+  int szPage,                     /* Database page-size in bytes */
+  PgHdr *pList,                   /* List of dirty pages to write */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit,                   /* True if this is a commit */
+  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
+){
+  int rc;                         /* Used to catch return codes */
+  u32 iFrame;                     /* Next frame address */
+  PgHdr *p;                       /* Iterator to run through pList with. */
+  PgHdr *pLast = 0;               /* Last frame in list */
+  int nExtra = 0;                 /* Number of extra copies of last page */
+  int szFrame;                    /* The size of a single frame */
+  i64 iOffset;                    /* Next byte to write in WAL file */
+  WalWriter w;                    /* The writer */
+
+  assert( pList );
+  assert( pWal->writeLock );
+
+  /* If this frame set completes a transaction, then nTruncate>0.  If
+  ** nTruncate==0 then this frame set does not complete the transaction. */
+  assert( (isCommit!=0)==(nTruncate!=0) );
+
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+  { int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
+    WALTRACE(("WAL%p: frame write begin. %d frames. mxFrame=%d. %s\n",
+              pWal, cnt, pWal->hdr.mxFrame, isCommit ? "Commit" : "Spill"));
+  }
+#endif
+
+  /* See if it is possible to write these frames into the start of the
+  ** log file, instead of appending to it at pWal->hdr.mxFrame.
+  */
+  if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
+    return rc;
+  }
+
+  /* If this is the first frame written into the log, write the WAL
+  ** header to the start of the WAL file. See comments at the top of
+  ** this source file for a description of the WAL header format.
+  */
+  iFrame = pWal->hdr.mxFrame;
+  if( iFrame==0 ){
+    u8 aWalHdr[WAL_HDRSIZE];      /* Buffer to assemble wal-header in */
+    u32 aCksum[2];                /* Checksum for wal-header */
+
+    sqlite3Put4byte(&aWalHdr[0], (WAL_MAGIC | SQLITE_BIGENDIAN));
+    sqlite3Put4byte(&aWalHdr[4], WAL_MAX_VERSION);
+    sqlite3Put4byte(&aWalHdr[8], szPage);
+    sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
+    if( pWal->nCkpt==0 ) sqlite3_randomness(8, pWal->hdr.aSalt);
+    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
+    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
+    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
+    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
+    
+    pWal->szPage = szPage;
+    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
+    pWal->hdr.aFrameCksum[0] = aCksum[0];
+    pWal->hdr.aFrameCksum[1] = aCksum[1];
+    pWal->truncateOnCommit = 1;
+
+    rc = sqlite3OsWrite(pWal->pWalFd, aWalHdr, sizeof(aWalHdr), 0);
+    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    /* Sync the header (unless SQLITE_IOCAP_SEQUENTIAL is true or unless
+    ** all syncing is turned off by PRAGMA synchronous=OFF).  Otherwise
+    ** an out-of-order write following a WAL restart could result in
+    ** database corruption.  See the ticket:
+    **
+    **     http://localhost:591/sqlite/info/ff5be73dee
+    */
+    if( pWal->syncHeader && sync_flags ){
+      rc = sqlite3OsSync(pWal->pWalFd, sync_flags & SQLITE_SYNC_MASK);
+      if( rc ) return rc;
+    }
+  }
+  assert( (int)pWal->szPage==szPage );
+
+  /* Setup information needed to write frames into the WAL */
+  w.pWal = pWal;
+  w.pFd = pWal->pWalFd;
+  w.iSyncPoint = 0;
+  w.syncFlags = sync_flags;
+  w.szPage = szPage;
+  iOffset = walFrameOffset(iFrame+1, szPage);
+  szFrame = szPage + WAL_FRAME_HDRSIZE;
+
+  /* Write all frames into the log file exactly once */
+  for(p=pList; p; p=p->pDirty){
+    int nDbSize;   /* 0 normally.  Positive == commit flag */
+    iFrame++;
+    assert( iOffset==walFrameOffset(iFrame, szPage) );
+    nDbSize = (isCommit && p->pDirty==0) ? nTruncate : 0;
+    rc = walWriteOneFrame(&w, p, nDbSize, iOffset);
+    if( rc ) return rc;
+    pLast = p;
+    iOffset += szFrame;
+  }
+
+  /* If this is the end of a transaction, then we might need to pad
+  ** the transaction and/or sync the WAL file.
+  **
+  ** Padding and syncing only occur if this set of frames complete a
+  ** transaction and if PRAGMA synchronous=FULL.  If synchronous==NORMAL
+  ** or synchonous==OFF, then no padding or syncing are needed.
+  **
+  ** If SQLITE_IOCAP_POWERSAFE_OVERWRITE is defined, then padding is not
+  ** needed and only the sync is done.  If padding is needed, then the
+  ** final frame is repeated (with its commit mark) until the next sector
+  ** boundary is crossed.  Only the part of the WAL prior to the last
+  ** sector boundary is synced; the part of the last frame that extends
+  ** past the sector boundary is written after the sync.
+  */
+  if( isCommit && (sync_flags & WAL_SYNC_TRANSACTIONS)!=0 ){
+    if( pWal->padToSectorBoundary ){
+      int sectorSize = sqlite3OsSectorSize(pWal->pWalFd);
+      w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;
+      while( iOffset<w.iSyncPoint ){
+        rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);
+        if( rc ) return rc;
+        iOffset += szFrame;
+        nExtra++;
+      }
+    }else{
+      rc = sqlite3OsSync(w.pFd, sync_flags & SQLITE_SYNC_MASK);
+    }
+  }
+
+  /* If this frame set completes the first transaction in the WAL and
+  ** if PRAGMA journal_size_limit is set, then truncate the WAL to the
+  ** journal size limit, if possible.
+  */
+  if( isCommit && pWal->truncateOnCommit && pWal->mxWalSize>=0 ){
+    i64 sz = pWal->mxWalSize;
+    if( walFrameOffset(iFrame+nExtra+1, szPage)>pWal->mxWalSize ){
+      sz = walFrameOffset(iFrame+nExtra+1, szPage);
+    }
+    walLimitSize(pWal, sz);
+    pWal->truncateOnCommit = 0;
+  }
+
+  /* Append data to the wal-index. It is not necessary to lock the 
+  ** wal-index to do this as the SQLITE_SHM_WRITE lock held on the wal-index
+  ** guarantees that there are no other writers, and no data that may
+  ** be in use by existing readers is being overwritten.
+  */
+  iFrame = pWal->hdr.mxFrame;
+  for(p=pList; p && rc==SQLITE_OK; p=p->pDirty){
+    iFrame++;
+    rc = walIndexAppend(pWal, iFrame, p->pgno);
+  }
+  while( rc==SQLITE_OK && nExtra>0 ){
+    iFrame++;
+    nExtra--;
+    rc = walIndexAppend(pWal, iFrame, pLast->pgno);
+  }
+
+  if( rc==SQLITE_OK ){
+    /* Update the private copy of the header. */
+    pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
+    testcase( szPage<=32768 );
+    testcase( szPage>=65536 );
+    pWal->hdr.mxFrame = iFrame;
+    if( isCommit ){
+      pWal->hdr.iChange++;
+      pWal->hdr.nPage = nTruncate;
+    }
+    /* If this is a commit, update the wal-index header too. */
+    if( isCommit ){
+      walIndexWriteHdr(pWal);
+      pWal->iCallback = iFrame;
+    }
+  }
+
+  WALTRACE(("WAL%p: frame write %s\n", pWal, rc ? "failed" : "ok"));
+  return rc;
+}
+
+/* 
+** This routine is called to implement sqlite3_wal_checkpoint() and
+** related interfaces.
+**
+** Obtain a CHECKPOINT lock and then backfill as much information as
+** we can from WAL into the database.
+**
+** If parameter xBusy is not NULL, it is a pointer to a busy-handler
+** callback. In this case this function runs a blocking checkpoint.
+*/
+SQLITE_PRIVATE int sqlite3WalCheckpoint(
+  Wal *pWal,                      /* Wal connection */
+  int eMode,                      /* PASSIVE, FULL or RESTART */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags to sync db file with (or 0) */
+  int nBuf,                       /* Size of temporary buffer */
+  u8 *zBuf,                       /* Temporary buffer to use */
+  int *pnLog,                     /* OUT: Number of frames in WAL */
+  int *pnCkpt                     /* OUT: Number of backfilled frames in WAL */
+){
+  int rc;                         /* Return code */
+  int isChanged = 0;              /* True if a new wal-index header is loaded */
+  int eMode2 = eMode;             /* Mode to pass to walCheckpoint() */
+
+  assert( pWal->ckptLock==0 );
+  assert( pWal->writeLock==0 );
+
+  if( pWal->readOnly ) return SQLITE_READONLY;
+  WALTRACE(("WAL%p: checkpoint begins\n", pWal));
+  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  if( rc ){
+    /* Usually this is SQLITE_BUSY meaning that another thread or process
+    ** is already running a checkpoint, or maybe a recovery.  But it might
+    ** also be SQLITE_IOERR. */
+    return rc;
+  }
+  pWal->ckptLock = 1;
+
+  /* If this is a blocking-checkpoint, then obtain the write-lock as well
+  ** to prevent any writers from running while the checkpoint is underway.
+  ** This has to be done before the call to walIndexReadHdr() below.
+  **
+  ** If the writer lock cannot be obtained, then a passive checkpoint is
+  ** run instead. Since the checkpointer is not holding the writer lock,
+  ** there is no point in blocking waiting for any readers. Assuming no 
+  ** other error occurs, this function will return SQLITE_BUSY to the caller.
+  */
+  if( eMode!=SQLITE_CHECKPOINT_PASSIVE ){
+    rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_WRITE_LOCK, 1);
+    if( rc==SQLITE_OK ){
+      pWal->writeLock = 1;
+    }else if( rc==SQLITE_BUSY ){
+      eMode2 = SQLITE_CHECKPOINT_PASSIVE;
+      rc = SQLITE_OK;
+    }
+  }
+
+  /* Read the wal-index header. */
+  if( rc==SQLITE_OK ){
+    rc = walIndexReadHdr(pWal, &isChanged);
+  }
+
+  /* Copy data from the log to the database file. */
+  if( rc==SQLITE_OK ){
+    if( pWal->hdr.mxFrame && walPagesize(pWal)!=nBuf ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = walCheckpoint(pWal, eMode2, xBusy, pBusyArg, sync_flags, zBuf);
+    }
+
+    /* If no error occurred, set the output variables. */
+    if( rc==SQLITE_OK || rc==SQLITE_BUSY ){
+      if( pnLog ) *pnLog = (int)pWal->hdr.mxFrame;
+      if( pnCkpt ) *pnCkpt = (int)(walCkptInfo(pWal)->nBackfill);
+    }
+  }
+
+  if( isChanged ){
+    /* If a new wal-index header was loaded before the checkpoint was 
+    ** performed, then the pager-cache associated with pWal is now
+    ** out of date. So zero the cached wal-index header to ensure that
+    ** next time the pager opens a snapshot on this database it knows that
+    ** the cache needs to be reset.
+    */
+    memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
+  }
+
+  /* Release the locks. */
+  sqlite3WalEndWriteTransaction(pWal);
+  walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  pWal->ckptLock = 0;
+  WALTRACE(("WAL%p: checkpoint %s\n", pWal, rc ? "failed" : "ok"));
+  return (rc==SQLITE_OK && eMode!=eMode2 ? SQLITE_BUSY : rc);
+}
+
+/* Return the value to pass to a sqlite3_wal_hook callback, the
+** number of frames in the WAL at the point of the last commit since
+** sqlite3WalCallback() was called.  If no commits have occurred since
+** the last call, then return 0.
+*/
+SQLITE_PRIVATE int sqlite3WalCallback(Wal *pWal){
+  u32 ret = 0;
+  if( pWal ){
+    ret = pWal->iCallback;
+    pWal->iCallback = 0;
+  }
+  return (int)ret;
+}
+
+/*
+** This function is called to change the WAL subsystem into or out
+** of locking_mode=EXCLUSIVE.
+**
+** If op is zero, then attempt to change from locking_mode=EXCLUSIVE
+** into locking_mode=NORMAL.  This means that we must acquire a lock
+** on the pWal->readLock byte.  If the WAL is already in locking_mode=NORMAL
+** or if the acquisition of the lock fails, then return 0.  If the
+** transition out of exclusive-mode is successful, return 1.  This
+** operation must occur while the pager is still holding the exclusive
+** lock on the main database file.
+**
+** If op is one, then change from locking_mode=NORMAL into 
+** locking_mode=EXCLUSIVE.  This means that the pWal->readLock must
+** be released.  Return 1 if the transition is made and 0 if the
+** WAL is already in exclusive-locking mode - meaning that this
+** routine is a no-op.  The pager must already hold the exclusive lock
+** on the main database file before invoking this operation.
+**
+** If op is negative, then do a dry-run of the op==1 case but do
+** not actually change anything. The pager uses this to see if it
+** should acquire the database exclusive lock prior to invoking
+** the op==1 case.
+*/
+SQLITE_PRIVATE int sqlite3WalExclusiveMode(Wal *pWal, int op){
+  int rc;
+  assert( pWal->writeLock==0 );
+  assert( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE || op==-1 );
+
+  /* pWal->readLock is usually set, but might be -1 if there was a 
+  ** prior error while attempting to acquire are read-lock. This cannot 
+  ** happen if the connection is actually in exclusive mode (as no xShmLock
+  ** locks are taken in this case). Nor should the pager attempt to
+  ** upgrade to exclusive-mode following such an error.
+  */
+  assert( pWal->readLock>=0 || pWal->lockError );
+  assert( pWal->readLock>=0 || (op<=0 && pWal->exclusiveMode==0) );
+
+  if( op==0 ){
+    if( pWal->exclusiveMode ){
+      pWal->exclusiveMode = 0;
+      if( walLockShared(pWal, WAL_READ_LOCK(pWal->readLock))!=SQLITE_OK ){
+        pWal->exclusiveMode = 1;
+      }
+      rc = pWal->exclusiveMode==0;
+    }else{
+      /* Already in locking_mode=NORMAL */
+      rc = 0;
+    }
+  }else if( op>0 ){
+    assert( pWal->exclusiveMode==0 );
+    assert( pWal->readLock>=0 );
+    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
+    pWal->exclusiveMode = 1;
+    rc = 1;
+  }else{
+    rc = pWal->exclusiveMode==0;
+  }
+  return rc;
+}
+
+/* 
+** Return true if the argument is non-NULL and the WAL module is using
+** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
+** WAL module is using shared-memory, return false. 
+*/
+SQLITE_PRIVATE int sqlite3WalHeapMemory(Wal *pWal){
+  return (pWal && pWal->exclusiveMode==WAL_HEAPMEMORY_MODE );
+}
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/*
+** If the argument is not NULL, it points to a Wal object that holds a
+** read-lock. This function returns the database page-size if it is known,
+** or zero if it is not (or if pWal is NULL).
+*/
+SQLITE_PRIVATE int sqlite3WalFramesize(Wal *pWal){
+  assert( pWal==0 || pWal->readLock>=0 );
+  return (pWal ? pWal->szPage : 0);
+}
+#endif
+
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+/************** End of wal.c *************************************************/
 /************** Begin file btmutex.c *****************************************/
 /*
 ** 2007 August 27
@@ -35307,8 +46985,6 @@ SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
 **
 *************************************************************************
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-**
 ** This file contains code used to implement mutexes on Btree objects.
 ** This code really belongs in btree.c.  But btree.c is getting too
 ** big and we want to break it down some.  This packaged seemed like
@@ -35327,8 +47003,6 @@ SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-**
 ** This file implements a external (disk-based) database using BTrees.
 ** For a detailed discussion of BTrees, refer to
 **
@@ -35366,9 +47040,9 @@ SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
 **
 ** The file is divided into pages.  The first page is called page 1,
 ** the second is page 2, and so forth.  A page number of zero indicates
-** "no such page".  The page size can be anything between 512 and 65536.
-** Each page can be either a btree page, a freelist page or an overflow
-** page.
+** "no such page".  The page size can be any power of 2 between 512 and 65536.
+** Each page can be either a btree page, a freelist page, an overflow
+** page, or a pointer-map page.
 **
 ** The first page is always a btree page.  The first 100 bytes of the first
 ** page contain a special header (the "file header") that describes the file.
@@ -35389,6 +47063,17 @@ SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
 **     36       4     Number of freelist pages in the file
 **     40      60     15 4-byte meta values passed to higher layers
 **
+**     40       4     Schema cookie
+**     44       4     File format of schema layer
+**     48       4     Size of page cache
+**     52       4     Largest root-page (auto/incr_vacuum)
+**     56       4     1=UTF-8 2=UTF16le 3=UTF16be
+**     60       4     User version
+**     64       4     Incremental vacuum mode
+**     68       4     unused
+**     72       4     unused
+**     76       4     unused
+**
 ** All of the integer values are big-endian (most significant byte first).
 **
 ** The file change counter is incremented when the database is changed
@@ -35522,16 +47207,11 @@ SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
 **      *     zero or more pages numbers of leaves
 */
 
-/* Round up a number to the next larger multiple of 8.  This is used
-** to force 8-byte alignment on 64-bit architectures.
-*/
-#define ROUND8(x)   ((x+7)&~7)
-
 
 /* The following value is the maximum cell size assuming a maximum page
 ** size give above.
 */
-#define MX_CELL_SIZE(pBt)  (pBt->pageSize-8)
+#define MX_CELL_SIZE(pBt)  ((int)(pBt->pageSize-8))
 
 /* The maximum number of cells on a single page of the database.  This
 ** assumes a minimum cell size of 6 bytes  (4 bytes for the cell itself
@@ -35590,18 +47270,20 @@ struct MemPage {
   u8 hasData;          /* True if this page stores data */
   u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
   u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
+  u8 max1bytePayload;  /* min(maxLocal,127) */
   u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
   u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
   u16 cellOffset;      /* Index in aData of first cell pointer */
   u16 nFree;           /* Number of free bytes on the page */
   u16 nCell;           /* Number of cells on this page, local and ovfl */
   u16 maskPage;        /* Mask for page offset */
-  struct _OvflCell {   /* Cells that will not fit on aData[] */
-    u8 *pCell;          /* Pointers to the body of the overflow cell */
-    u16 idx;            /* Insert this cell before idx-th non-overflow cell */
-  } aOvfl[5];
+  u16 aiOvfl[5];       /* Insert the i-th overflow cell before the aiOvfl-th
+                       ** non-overflow cell */
+  u8 *apOvfl[5];       /* Pointers to the body of overflow cells */
   BtShared *pBt;       /* Pointer to BtShared that this page is part of */
   u8 *aData;           /* Pointer to disk image of the page data */
+  u8 *aDataEnd;        /* One byte past the end of usable data */
+  u8 *aCellIdx;        /* The cell index area */
   DbPage *pDbPage;     /* Pager page handle */
   Pgno pgno;           /* Page number for this page */
 };
@@ -35613,6 +47295,24 @@ struct MemPage {
 */
 #define EXTRA_SIZE sizeof(MemPage)
 
+/*
+** A linked list of the following structures is stored at BtShared.pLock.
+** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor 
+** is opened on the table with root page BtShared.iTable. Locks are removed
+** from this list when a transaction is committed or rolled back, or when
+** a btree handle is closed.
+*/
+struct BtLock {
+  Btree *pBtree;        /* Btree handle holding this lock */
+  Pgno iTable;          /* Root page of table */
+  u8 eLock;             /* READ_LOCK or WRITE_LOCK */
+  BtLock *pNext;        /* Next in BtShared.pLock list */
+};
+
+/* Candidate values for BtLock.eLock */
+#define READ_LOCK     1
+#define WRITE_LOCK    2
+
 /* A Btree handle
 **
 ** A database connection contains a pointer to an instance of
@@ -35622,8 +47322,8 @@ struct MemPage {
 ** this structure.
 **
 ** For some database files, the same underlying database cache might be 
-** shared between multiple connections.  In that case, each contection
-** has it own pointer to this object.  But each instance of this object
+** shared between multiple connections.  In that case, each connection
+** has it own instance of this object.  But each instance of this object
 ** points to the same BtShared object.  The database cache and the
 ** schema associated with the database file are all contained within
 ** the BtShared object.
@@ -35631,7 +47331,7 @@ struct MemPage {
 ** All fields in this structure are accessed under sqlite3.mutex.
 ** The pBt pointer itself may not be changed while there exists cursors 
 ** in the referenced BtShared that point back to this Btree since those
-** cursors have to do go through this Btree to find their BtShared and
+** cursors have to go through this Btree to find their BtShared and
 ** they often do so without holding sqlite3.mutex.
 */
 struct Btree {
@@ -35641,8 +47341,12 @@ struct Btree {
   u8 sharable;       /* True if we can share pBt with another db */
   u8 locked;         /* True if db currently has pBt locked */
   int wantToLock;    /* Number of nested calls to sqlite3BtreeEnter() */
+  int nBackup;       /* Number of backup operations reading this btree */
   Btree *pNext;      /* List of other sharable Btrees from the same db */
   Btree *pPrev;      /* Back pointer of the same list */
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  BtLock lock;       /* Object used to lock page 1 */
+#endif
 };
 
 /*
@@ -35659,7 +47363,7 @@ struct Btree {
 /*
 ** An instance of this object represents a single database file.
 ** 
-** A single database file can be in use as the same time by two
+** A single database file can be in use at the same time by two
 ** or more database connections.  When two or more connections are
 ** sharing the same database file, each connection has it own
 ** private Btree object for the file and each of those Btrees points
@@ -35672,39 +47376,70 @@ struct Btree {
 ** may not be modified once it is initially set as long as nRef>0.
 ** The pSchema field may be set once under BtShared.mutex and
 ** thereafter is unchanged as long as nRef>0.
+**
+** isPending:
+**
+**   If a BtShared client fails to obtain a write-lock on a database
+**   table (because there exists one or more read-locks on the table),
+**   the shared-cache enters 'pending-lock' state and isPending is
+**   set to true.
+**
+**   The shared-cache leaves the 'pending lock' state when either of
+**   the following occur:
+**
+**     1) The current writer (BtShared.pWriter) concludes its transaction, OR
+**     2) The number of locks held by other connections drops to zero.
+**
+**   while in the 'pending-lock' state, no connection may start a new
+**   transaction.
+**
+**   This feature is included to help prevent writer-starvation.
 */
 struct BtShared {
   Pager *pPager;        /* The page cache */
   sqlite3 *db;          /* Database connection currently using this Btree */
   BtCursor *pCursor;    /* A list of all open cursors */
   MemPage *pPage1;      /* First page of the database */
-  u8 inStmt;            /* True if we are in a statement subtransaction */
-  u8 readOnly;          /* True if the underlying file is readonly */
-  u8 pageSizeFixed;     /* True if the page size can no longer be changed */
+  u8 openFlags;         /* Flags to sqlite3BtreeOpen() */
 #ifndef SQLITE_OMIT_AUTOVACUUM
   u8 autoVacuum;        /* True if auto-vacuum is enabled */
   u8 incrVacuum;        /* True if incr-vacuum is enabled */
 #endif
-  u16 pageSize;         /* Total number of bytes on a page */
-  u16 usableSize;       /* Number of usable bytes on each page */
+  u8 inTransaction;     /* Transaction state */
+  u8 max1bytePayload;   /* Maximum first byte of cell for a 1-byte payload */
+  u16 btsFlags;         /* Boolean parameters.  See BTS_* macros below */
   u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
   u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
   u16 maxLeaf;          /* Maximum local payload in a LEAFDATA table */
   u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
-  u8 inTransaction;     /* Transaction state */
+  u32 pageSize;         /* Total number of bytes on a page */
+  u32 usableSize;       /* Number of usable bytes on each page */
   int nTransaction;     /* Number of open transactions (read + write) */
+  u32 nPage;            /* Number of pages in the database */
   void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
   void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
-  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this struct */
+  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this object */
+  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
 #ifndef SQLITE_OMIT_SHARED_CACHE
   int nRef;             /* Number of references to this structure */
   BtShared *pNext;      /* Next on a list of sharable BtShared structs */
   BtLock *pLock;        /* List of locks held on this shared-btree struct */
-  Btree *pExclusive;    /* Btree with an EXCLUSIVE lock on the whole db */
+  Btree *pWriter;       /* Btree with currently open write transaction */
 #endif
   u8 *pTmpSpace;        /* BtShared.pageSize bytes of space for tmp use */
 };
 
+/*
+** Allowed values for BtShared.btsFlags
+*/
+#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
+#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
+#define BTS_SECURE_DELETE    0x0004   /* PRAGMA secure_delete is enabled */
+#define BTS_INITIALLY_EMPTY  0x0008   /* Database was empty at trans start */
+#define BTS_NO_WAL           0x0010   /* Do not open write-ahead-log files */
+#define BTS_EXCLUSIVE        0x0020   /* pWriter has an exclusive lock */
+#define BTS_PENDING          0x0040   /* Waiting for read-locks to clear */
+
 /*
 ** An instance of the following structure is used to hold information
 ** about a cell.  The parseCellPtr() function fills in this structure
@@ -35712,8 +47447,8 @@ struct BtShared {
 */
 typedef struct CellInfo CellInfo;
 struct CellInfo {
-  u8 *pCell;     /* Pointer to the start of cell content */
   i64 nKey;      /* The key for INTKEY tables, or number of bytes in key */
+  u8 *pCell;     /* Pointer to the start of cell content */
   u32 nData;     /* Number of bytes of data */
   u32 nPayload;  /* Total amount of payload */
   u16 nHeader;   /* Size of the cell content header in bytes */
@@ -35740,7 +47475,7 @@ struct CellInfo {
 ** The entry is identified by its MemPage and the index in
 ** MemPage.aCell[] of the entry.
 **
-** When a single database file can shared by two more database connections,
+** A single database file can be shared by two more database connections,
 ** but cursors cannot be shared.  Each cursor is associated with a
 ** particular database connection identified BtCursor.pBtree.db.
 **
@@ -35752,25 +47487,26 @@ struct BtCursor {
   BtShared *pBt;            /* The BtShared this cursor points to */
   BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
   struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
+#ifndef SQLITE_OMIT_INCRBLOB
+  Pgno *aOverflow;          /* Cache of overflow page locations */
+#endif
   Pgno pgnoRoot;            /* The root page of this tree */
+  sqlite3_int64 cachedRowid; /* Next rowid cache.  0 means not valid */
   CellInfo info;            /* A parse of the cell we are pointing at */
+  i64 nKey;        /* Size of pKey, or last integer key */
+  void *pKey;      /* Saved key that was cursor's last known position */
+  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive */
   u8 wrFlag;                /* True if writable */
   u8 atLast;                /* Cursor pointing to the last entry */
   u8 validNKey;             /* True if info.nKey is valid */
   u8 eState;                /* One of the CURSOR_XXX constants (see below) */
-  void *pKey;      /* Saved key that was cursor's last known position */
-  i64 nKey;        /* Size of pKey, or last integer key */
-  int skip;        /* (skip<0) -> Prev() is a no-op. (skip>0) -> Next() is */
 #ifndef SQLITE_OMIT_INCRBLOB
   u8 isIncrblobHandle;      /* True if this cursor is an incr. io handle */
-  Pgno *aOverflow;          /* Cache of overflow page locations */
-#endif
-#ifndef NDEBUG
-  u8 pagesShuffled;         /* True if Btree pages are rearranged by balance()*/
 #endif
+  u8 hints;                             /* As configured by CursorSetHints() */
   i16 iPage;                            /* Index of current page in apPage */
-  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
   u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
+  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
 };
 
 /*
@@ -35803,36 +47539,10 @@ struct BtCursor {
 #define CURSOR_REQUIRESEEK       2
 #define CURSOR_FAULT             3
 
-/* The database page the PENDING_BYTE occupies. This page is never used.
-** TODO: This macro is very similary to PAGER_MJ_PGNO() in pager.c. They
-** should possibly be consolidated (presumably in pager.h).
-**
-** If disk I/O is omitted (meaning that the database is stored purely
-** in memory) then there is no pending byte.
+/* 
+** The database page the PENDING_BYTE occupies. This page is never used.
 */
-#ifdef SQLITE_OMIT_DISKIO
-# define PENDING_BYTE_PAGE(pBt)  0x7fffffff
-#else
-# define PENDING_BYTE_PAGE(pBt) ((Pgno)((PENDING_BYTE/(pBt)->pageSize)+1))
-#endif
-
-/*
-** A linked list of the following structures is stored at BtShared.pLock.
-** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor 
-** is opened on the table with root page BtShared.iTable. Locks are removed
-** from this list when a transaction is committed or rolled back, or when
-** a btree handle is closed.
-*/
-struct BtLock {
-  Btree *pBtree;        /* Btree handle holding this lock */
-  Pgno iTable;          /* Root page of table */
-  u8 eLock;             /* READ_LOCK or WRITE_LOCK */
-  BtLock *pNext;        /* Next in BtShared.pLock list */
-};
-
-/* Candidate values for BtLock.eLock */
-#define READ_LOCK     1
-#define WRITE_LOCK    2
+# define PENDING_BYTE_PAGE(pBt) PAGER_MJ_PGNO(pBt)
 
 /*
 ** These macros define the location of the pointer-map entry for a 
@@ -35915,13 +47625,19 @@ struct BtLock {
 /*
 ** This structure is passed around through all the sanity checking routines
 ** in order to keep track of some global state information.
+**
+** The aRef[] array is allocated so that there is 1 bit for each page in
+** the database. As the integrity-check proceeds, for each page used in
+** the database the corresponding bit is set. This allows integrity-check to 
+** detect pages that are used twice and orphaned pages (both of which 
+** indicate corruption).
 */
 typedef struct IntegrityCk IntegrityCk;
 struct IntegrityCk {
   BtShared *pBt;    /* The tree being checked out */
   Pager *pPager;    /* The associated pager.  Also accessible by pBt->pPager */
+  u8 *aPgRef;       /* 1 bit per page in the db (see above) */
   Pgno nPage;       /* Number of pages in the database */
-  int *anRef;       /* Number of times each page is referenced */
   int mxErr;        /* Stop accumulating errors when this reaches zero */
   int nErr;         /* Number of messages written to zErrMsg so far */
   int mallocFailed; /* A memory allocation error has occurred */
@@ -35929,29 +47645,47 @@ struct IntegrityCk {
 };
 
 /*
-** Read or write a two- and four-byte big-endian integer values.
+** Routines to read or write a two- and four-byte big-endian integer values.
 */
 #define get2byte(x)   ((x)[0]<<8 | (x)[1])
 #define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
 #define get4byte sqlite3Get4byte
 #define put4byte sqlite3Put4byte
 
-/*
-** Internal routines that should be accessed by the btree layer only.
-*/
-SQLITE_PRIVATE int sqlite3BtreeGetPage(BtShared*, Pgno, MemPage**, int);
-SQLITE_PRIVATE int sqlite3BtreeInitPage(MemPage *pPage);
-SQLITE_PRIVATE void sqlite3BtreeParseCellPtr(MemPage*, u8*, CellInfo*);
-SQLITE_PRIVATE void sqlite3BtreeParseCell(MemPage*, int, CellInfo*);
-SQLITE_PRIVATE int sqlite3BtreeRestoreCursorPosition(BtCursor *pCur);
-SQLITE_PRIVATE void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur);
-SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur);
-SQLITE_PRIVATE void sqlite3BtreeMoveToParent(BtCursor *pCur);
-
 /************** End of btreeInt.h ********************************************/
 /************** Continuing where we left off in btmutex.c ********************/
-#if SQLITE_THREADSAFE && !defined(SQLITE_OMIT_SHARED_CACHE)
+#ifndef SQLITE_OMIT_SHARED_CACHE
+#if SQLITE_THREADSAFE
 
+/*
+** Obtain the BtShared mutex associated with B-Tree handle p. Also,
+** set BtShared.db to the database handle associated with p and the
+** p->locked boolean to true.
+*/
+static void lockBtreeMutex(Btree *p){
+  assert( p->locked==0 );
+  assert( sqlite3_mutex_notheld(p->pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  sqlite3_mutex_enter(p->pBt->mutex);
+  p->pBt->db = p->db;
+  p->locked = 1;
+}
+
+/*
+** Release the BtShared mutex associated with B-Tree handle p and
+** clear the p->locked boolean.
+*/
+static void unlockBtreeMutex(Btree *p){
+  BtShared *pBt = p->pBt;
+  assert( p->locked==1 );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  assert( p->db==pBt->db );
+
+  sqlite3_mutex_leave(pBt->mutex);
+  p->locked = 0;
+}
 
 /*
 ** Enter a mutex on the given BTree object.
@@ -35989,6 +47723,10 @@ SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
   /* We should already hold a lock on the database connection */
   assert( sqlite3_mutex_held(p->db->mutex) );
 
+  /* Unless the database is sharable and unlocked, then BtShared.db
+  ** should already be set correctly. */
+  assert( (p->locked==0 && p->sharable) || p->pBt->db==p->db );
+
   if( !p->sharable ) return;
   p->wantToLock++;
   if( p->locked ) return;
@@ -35998,6 +47736,7 @@ SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
   ** procedure that follows.  Just be sure not to block.
   */
   if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
+    p->pBt->db = p->db;
     p->locked = 1;
     return;
   }
@@ -36012,16 +47751,13 @@ SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
     assert( pLater->pNext==0 || pLater->pNext->pBt>pLater->pBt );
     assert( !pLater->locked || pLater->wantToLock>0 );
     if( pLater->locked ){
-      sqlite3_mutex_leave(pLater->pBt->mutex);
-      pLater->locked = 0;
+      unlockBtreeMutex(pLater);
     }
   }
-  sqlite3_mutex_enter(p->pBt->mutex);
-  p->locked = 1;
+  lockBtreeMutex(p);
   for(pLater=p->pNext; pLater; pLater=pLater->pNext){
     if( pLater->wantToLock ){
-      sqlite3_mutex_enter(pLater->pBt->mutex);
-      pLater->locked = 1;
+      lockBtreeMutex(pLater);
     }
   }
 }
@@ -36034,25 +47770,25 @@ SQLITE_PRIVATE void sqlite3BtreeLeave(Btree *p){
     assert( p->wantToLock>0 );
     p->wantToLock--;
     if( p->wantToLock==0 ){
-      assert( p->locked );
-      sqlite3_mutex_leave(p->pBt->mutex);
-      p->locked = 0;
+      unlockBtreeMutex(p);
     }
   }
 }
 
 #ifndef NDEBUG
 /*
-** Return true if the BtShared mutex is held on the btree.  
-**
-** This routine makes no determination one why or another if the
-** database connection mutex is held.
+** Return true if the BtShared mutex is held on the btree, or if the
+** B-Tree is not marked as sharable.
 **
 ** This routine is used only from within assert() statements.
 */
 SQLITE_PRIVATE int sqlite3BtreeHoldsMutex(Btree *p){
-  return (p->sharable==0 ||
-             (p->locked && p->wantToLock && sqlite3_mutex_held(p->pBt->mutex)));
+  assert( p->sharable==0 || p->locked==0 || p->wantToLock>0 );
+  assert( p->sharable==0 || p->locked==0 || p->db==p->pBt->db );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->pBt->mutex) );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->db->mutex) );
+
+  return (p->sharable==0 || p->locked);
 }
 #endif
 
@@ -36088,29 +47824,11 @@ SQLITE_PRIVATE void sqlite3BtreeLeaveCursor(BtCursor *pCur){
 */
 SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
   int i;
-  Btree *p, *pLater;
+  Btree *p;
   assert( sqlite3_mutex_held(db->mutex) );
   for(i=0; i<db->nDb; i++){
     p = db->aDb[i].pBt;
-    if( p && p->sharable ){
-      p->wantToLock++;
-      if( !p->locked ){
-        assert( p->wantToLock==1 );
-        while( p->pPrev ) p = p->pPrev;
-        while( p->locked && p->pNext ) p = p->pNext;
-        for(pLater = p->pNext; pLater; pLater=pLater->pNext){
-          if( pLater->locked ){
-            sqlite3_mutex_leave(pLater->pBt->mutex);
-            pLater->locked = 0;
-          }
-        }
-        while( p ){
-          sqlite3_mutex_enter(p->pBt->mutex);
-          p->locked++;
-          p = p->pNext;
-        }
-      }
-    }
+    if( p ) sqlite3BtreeEnter(p);
   }
 }
 SQLITE_PRIVATE void sqlite3BtreeLeaveAll(sqlite3 *db){
@@ -36119,18 +47837,18 @@ SQLITE_PRIVATE void sqlite3BtreeLeaveAll(sqlite3 *db){
   assert( sqlite3_mutex_held(db->mutex) );
   for(i=0; i<db->nDb; i++){
     p = db->aDb[i].pBt;
-    if( p && p->sharable ){
-      assert( p->wantToLock>0 );
-      p->wantToLock--;
-      if( p->wantToLock==0 ){
-        assert( p->locked );
-        sqlite3_mutex_leave(p->pBt->mutex);
-        p->locked = 0;
-      }
-    }
+    if( p ) sqlite3BtreeLeave(p);
   }
 }
 
+/*
+** Return true if a particular Btree requires a lock.  Return FALSE if
+** no lock is ever required since it is not sharable.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSharable(Btree *p){
+  return p->sharable;
+}
+
 #ifndef NDEBUG
 /*
 ** Return true if the current thread holds the database connection
@@ -36155,96 +47873,56 @@ SQLITE_PRIVATE int sqlite3BtreeHoldsAllMutexes(sqlite3 *db){
 }
 #endif /* NDEBUG */
 
-/*
-** Add a new Btree pointer to a BtreeMutexArray. 
-** if the pointer can possibly be shared with
-** another database connection.
-**
-** The pointers are kept in sorted order by pBtree->pBt.  That
-** way when we go to enter all the mutexes, we can enter them
-** in order without every having to backup and retry and without
-** worrying about deadlock.
-**
-** The number of shared btrees will always be small (usually 0 or 1)
-** so an insertion sort is an adequate algorithm here.
-*/
-SQLITE_PRIVATE void sqlite3BtreeMutexArrayInsert(BtreeMutexArray *pArray, Btree *pBtree){
-  int i, j;
-  BtShared *pBt;
-  if( pBtree==0 || pBtree->sharable==0 ) return;
 #ifndef NDEBUG
-  {
-    for(i=0; i<pArray->nMutex; i++){
-      assert( pArray->aBtree[i]!=pBtree );
-    }
-  }
-#endif
-  assert( pArray->nMutex>=0 );
-  assert( pArray->nMutex<ArraySize(pArray->aBtree)-1 );
-  pBt = pBtree->pBt;
-  for(i=0; i<pArray->nMutex; i++){
-    assert( pArray->aBtree[i]!=pBtree );
-    if( pArray->aBtree[i]->pBt>pBt ){
-      for(j=pArray->nMutex; j>i; j--){
-        pArray->aBtree[j] = pArray->aBtree[j-1];
-      }
-      pArray->aBtree[i] = pBtree;
-      pArray->nMutex++;
-      return;
-    }
-  }
-  pArray->aBtree[pArray->nMutex++] = pBtree;
-}
-
 /*
-** Enter the mutex of every btree in the array.  This routine is
-** called at the beginning of sqlite3VdbeExec().  The mutexes are
-** exited at the end of the same function.
+** Return true if the correct mutexes are held for accessing the
+** db->aDb[iDb].pSchema structure.  The mutexes required for schema
+** access are:
+**
+**   (1) The mutex on db
+**   (2) if iDb!=1, then the mutex on db->aDb[iDb].pBt.
+**
+** If pSchema is not NULL, then iDb is computed from pSchema and
+** db using sqlite3SchemaToIndex().
 */
-SQLITE_PRIVATE void sqlite3BtreeMutexArrayEnter(BtreeMutexArray *pArray){
-  int i;
-  for(i=0; i<pArray->nMutex; i++){
-    Btree *p = pArray->aBtree[i];
-    /* Some basic sanity checking */
-    assert( i==0 || pArray->aBtree[i-1]->pBt<p->pBt );
-    assert( !p->locked || p->wantToLock>0 );
-
-    /* We should already hold a lock on the database connection */
-    assert( sqlite3_mutex_held(p->db->mutex) );
-
-    p->wantToLock++;
-    if( !p->locked && p->sharable ){
-      sqlite3_mutex_enter(p->pBt->mutex);
-      p->locked = 1;
-    }
-  }
+SQLITE_PRIVATE int sqlite3SchemaMutexHeld(sqlite3 *db, int iDb, Schema *pSchema){
+  Btree *p;
+  assert( db!=0 );
+  if( pSchema ) iDb = sqlite3SchemaToIndex(db, pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+  if( !sqlite3_mutex_held(db->mutex) ) return 0;
+  if( iDb==1 ) return 1;
+  p = db->aDb[iDb].pBt;
+  assert( p!=0 );
+  return p->sharable==0 || p->locked==1;
 }
+#endif /* NDEBUG */
 
+#else /* SQLITE_THREADSAFE>0 above.  SQLITE_THREADSAFE==0 below */
 /*
-** Leave the mutex of every btree in the group.
+** The following are special cases for mutex enter routines for use
+** in single threaded applications that use shared cache.  Except for
+** these two routines, all mutex operations are no-ops in that case and
+** are null #defines in btree.h.
+**
+** If shared cache is disabled, then all btree mutex routines, including
+** the ones below, are no-ops and are null #defines in btree.h.
 */
-SQLITE_PRIVATE void sqlite3BtreeMutexArrayLeave(BtreeMutexArray *pArray){
+
+SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
+  p->pBt->db = p->db;
+}
+SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
   int i;
-  for(i=0; i<pArray->nMutex; i++){
-    Btree *p = pArray->aBtree[i];
-    /* Some basic sanity checking */
-    assert( i==0 || pArray->aBtree[i-1]->pBt<p->pBt );
-    assert( p->locked || !p->sharable );
-    assert( p->wantToLock>0 );
-
-    /* We should already hold a lock on the database connection */
-    assert( sqlite3_mutex_held(p->db->mutex) );
-
-    p->wantToLock--;
-    if( p->wantToLock==0 && p->locked ){
-      sqlite3_mutex_leave(p->pBt->mutex);
-      p->locked = 0;
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      p->pBt->db = p->db;
     }
   }
 }
-
-
-#endif  /* SQLITE_THREADSAFE && !SQLITE_OMIT_SHARED_CACHE */
+#endif /* if SQLITE_THREADSAFE */
+#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */
 
 /************** End of btmutex.c *********************************************/
 /************** Begin file btree.c *******************************************/
@@ -36259,8 +47937,6 @@ SQLITE_PRIVATE void sqlite3BtreeMutexArrayLeave(BtreeMutexArray *pArray){
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-**
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
 ** Including a description of file format and an overview of operation.
@@ -36277,13 +47953,22 @@ static const char zMagicHeader[] = SQLITE_FILE_HEADER;
 ** macro.
 */
 #if 0
-int sqlite3BtreeTrace=0;  /* True to enable tracing */
+int sqlite3BtreeTrace=1;  /* True to enable tracing */
 # define TRACE(X)  if(sqlite3BtreeTrace){printf X;fflush(stdout);}
 #else
 # define TRACE(X)
 #endif
 
-
+/*
+** Extract a 2-byte big-endian integer from an array of unsigned bytes.
+** But if the value is zero, make it 65536.
+**
+** This routine is used to extract the "offset to cell content area" value
+** from the header of a btree page.  If the page size is 65536 and the page
+** is empty, the offset should be 65536, but the 2-byte value stores zero.
+** This routine makes the necessary adjustment to 65536.
+*/
+#define get2byteNotZero(X)  (((((int)get2byte(X))-1)&0xffff)+1)
 
 #ifndef SQLITE_OMIT_SHARED_CACHE
 /*
@@ -36291,6 +47976,8 @@ int sqlite3BtreeTrace=0;  /* True to enable tracing */
 ** in shared cache.  This variable has file scope during normal builds,
 ** but the test harness needs to access it so we make it global for 
 ** test builds.
+**
+** Access to this variable is protected by SQLITE_MUTEX_STATIC_MASTER.
 */
 #ifdef SQLITE_TEST
 SQLITE_PRIVATE BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
@@ -36314,42 +48001,168 @@ SQLITE_API int sqlite3_enable_shared_cache(int enable){
 #endif
 
 
-/*
-** Forward declaration
-*/
-static int checkReadLocks(Btree*, Pgno, BtCursor*, i64);
-
 
 #ifdef SQLITE_OMIT_SHARED_CACHE
   /*
-  ** The functions queryTableLock(), lockTable() and unlockAllTables()
+  ** The functions querySharedCacheTableLock(), setSharedCacheTableLock(),
+  ** and clearAllSharedCacheTableLocks()
   ** manipulate entries in the BtShared.pLock linked list used to store
   ** shared-cache table level locks. If the library is compiled with the
   ** shared-cache feature disabled, then there is only ever one user
   ** of each BtShared structure and so this locking is not necessary. 
   ** So define the lock related functions as no-ops.
   */
-  #define queryTableLock(a,b,c) SQLITE_OK
-  #define lockTable(a,b,c) SQLITE_OK
-  #define unlockAllTables(a)
+  #define querySharedCacheTableLock(a,b,c) SQLITE_OK
+  #define setSharedCacheTableLock(a,b,c) SQLITE_OK
+  #define clearAllSharedCacheTableLocks(a)
+  #define downgradeAllSharedCacheTableLocks(a)
+  #define hasSharedCacheTableLock(a,b,c,d) 1
+  #define hasReadConflicts(a, b) 0
 #endif
 
 #ifndef SQLITE_OMIT_SHARED_CACHE
+
+#ifdef SQLITE_DEBUG
 /*
-** Query to see if btree handle p may obtain a lock of type eLock 
-** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
-** SQLITE_OK if the lock may be obtained (by calling lockTable()), or
-** SQLITE_LOCKED if not.
+**** This function is only used as part of an assert() statement. ***
+**
+** Check to see if pBtree holds the required locks to read or write to the 
+** table with root page iRoot.   Return 1 if it does and 0 if not.
+**
+** For example, when writing to a table with root-page iRoot via 
+** Btree connection pBtree:
+**
+**    assert( hasSharedCacheTableLock(pBtree, iRoot, 0, WRITE_LOCK) );
+**
+** When writing to an index that resides in a sharable database, the 
+** caller should have first obtained a lock specifying the root page of
+** the corresponding table. This makes things a bit more complicated,
+** as this module treats each table as a separate structure. To determine
+** the table corresponding to the index being written, this
+** function has to search through the database schema.
+**
+** Instead of a lock on the table/index rooted at page iRoot, the caller may
+** hold a write-lock on the schema table (root page 1). This is also
+** acceptable.
 */
-static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){
+static int hasSharedCacheTableLock(
+  Btree *pBtree,         /* Handle that must hold lock */
+  Pgno iRoot,            /* Root page of b-tree */
+  int isIndex,           /* True if iRoot is the root of an index b-tree */
+  int eLockType          /* Required lock type (READ_LOCK or WRITE_LOCK) */
+){
+  Schema *pSchema = (Schema *)pBtree->pBt->pSchema;
+  Pgno iTab = 0;
+  BtLock *pLock;
+
+  /* If this database is not shareable, or if the client is reading
+  ** and has the read-uncommitted flag set, then no lock is required. 
+  ** Return true immediately.
+  */
+  if( (pBtree->sharable==0)
+   || (eLockType==READ_LOCK && (pBtree->db->flags & SQLITE_ReadUncommitted))
+  ){
+    return 1;
+  }
+
+  /* If the client is reading  or writing an index and the schema is
+  ** not loaded, then it is too difficult to actually check to see if
+  ** the correct locks are held.  So do not bother - just return true.
+  ** This case does not come up very often anyhow.
+  */
+  if( isIndex && (!pSchema || (pSchema->flags&DB_SchemaLoaded)==0) ){
+    return 1;
+  }
+
+  /* Figure out the root-page that the lock should be held on. For table
+  ** b-trees, this is just the root page of the b-tree being read or
+  ** written. For index b-trees, it is the root page of the associated
+  ** table.  */
+  if( isIndex ){
+    HashElem *p;
+    for(p=sqliteHashFirst(&pSchema->idxHash); p; p=sqliteHashNext(p)){
+      Index *pIdx = (Index *)sqliteHashData(p);
+      if( pIdx->tnum==(int)iRoot ){
+        iTab = pIdx->pTable->tnum;
+      }
+    }
+  }else{
+    iTab = iRoot;
+  }
+
+  /* Search for the required lock. Either a write-lock on root-page iTab, a 
+  ** write-lock on the schema table, or (if the client is reading) a
+  ** read-lock on iTab will suffice. Return 1 if any of these are found.  */
+  for(pLock=pBtree->pBt->pLock; pLock; pLock=pLock->pNext){
+    if( pLock->pBtree==pBtree 
+     && (pLock->iTable==iTab || (pLock->eLock==WRITE_LOCK && pLock->iTable==1))
+     && pLock->eLock>=eLockType 
+    ){
+      return 1;
+    }
+  }
+
+  /* Failed to find the required lock. */
+  return 0;
+}
+#endif /* SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+**** This function may be used as part of assert() statements only. ****
+**
+** Return true if it would be illegal for pBtree to write into the
+** table or index rooted at iRoot because other shared connections are
+** simultaneously reading that same table or index.
+**
+** It is illegal for pBtree to write if some other Btree object that
+** shares the same BtShared object is currently reading or writing
+** the iRoot table.  Except, if the other Btree object has the
+** read-uncommitted flag set, then it is OK for the other object to
+** have a read cursor.
+**
+** For example, before writing to any part of the table or index
+** rooted at page iRoot, one should call:
+**
+**    assert( !hasReadConflicts(pBtree, iRoot) );
+*/
+static int hasReadConflicts(Btree *pBtree, Pgno iRoot){
+  BtCursor *p;
+  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+    if( p->pgnoRoot==iRoot 
+     && p->pBtree!=pBtree
+     && 0==(p->pBtree->db->flags & SQLITE_ReadUncommitted)
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif    /* #ifdef SQLITE_DEBUG */
+
+/*
+** Query to see if Btree handle p may obtain a lock of type eLock 
+** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
+** SQLITE_OK if the lock may be obtained (by calling
+** setSharedCacheTableLock()), or SQLITE_LOCKED if not.
+*/
+static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
   BtShared *pBt = p->pBt;
   BtLock *pIter;
 
   assert( sqlite3BtreeHoldsMutex(p) );
   assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
   assert( p->db!=0 );
+  assert( !(p->db->flags&SQLITE_ReadUncommitted)||eLock==WRITE_LOCK||iTab==1 );
   
-  /* This is a no-op if the shared-cache is not enabled */
+  /* If requesting a write-lock, then the Btree must have an open write
+  ** transaction on this file. And, obviously, for this to be so there 
+  ** must be an open write transaction on the file itself.
+  */
+  assert( eLock==READ_LOCK || (p==pBt->pWriter && p->inTrans==TRANS_WRITE) );
+  assert( eLock==READ_LOCK || pBt->inTransaction==TRANS_WRITE );
+  
+  /* This routine is a no-op if the shared-cache is not enabled */
   if( !p->sharable ){
     return SQLITE_OK;
   }
@@ -36357,34 +48170,30 @@ static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){
   /* If some other connection is holding an exclusive lock, the
   ** requested lock may not be obtained.
   */
-  if( pBt->pExclusive && pBt->pExclusive!=p ){
-    return SQLITE_LOCKED;
+  if( pBt->pWriter!=p && (pBt->btsFlags & BTS_EXCLUSIVE)!=0 ){
+    sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
+    return SQLITE_LOCKED_SHAREDCACHE;
   }
 
-  /* This (along with lockTable()) is where the ReadUncommitted flag is
-  ** dealt with. If the caller is querying for a read-lock and the flag is
-  ** set, it is unconditionally granted - even if there are write-locks
-  ** on the table. If a write-lock is requested, the ReadUncommitted flag
-  ** is not considered.
-  **
-  ** In function lockTable(), if a read-lock is demanded and the 
-  ** ReadUncommitted flag is set, no entry is added to the locks list 
-  ** (BtShared.pLock).
-  **
-  ** To summarize: If the ReadUncommitted flag is set, then read cursors do
-  ** not create or respect table locks. The locking procedure for a 
-  ** write-cursor does not change.
-  */
-  if( 
-    0==(p->db->flags&SQLITE_ReadUncommitted) || 
-    eLock==WRITE_LOCK ||
-    iTab==MASTER_ROOT
-  ){
-    for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
-      if( pIter->pBtree!=p && pIter->iTable==iTab && 
-          (pIter->eLock!=eLock || eLock!=READ_LOCK) ){
-        return SQLITE_LOCKED;
+  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+    /* The condition (pIter->eLock!=eLock) in the following if(...) 
+    ** statement is a simplification of:
+    **
+    **   (eLock==WRITE_LOCK || pIter->eLock==WRITE_LOCK)
+    **
+    ** since we know that if eLock==WRITE_LOCK, then no other connection
+    ** may hold a WRITE_LOCK on any table in this file (since there can
+    ** only be a single writer).
+    */
+    assert( pIter->eLock==READ_LOCK || pIter->eLock==WRITE_LOCK );
+    assert( eLock==READ_LOCK || pIter->pBtree==p || pIter->eLock==READ_LOCK);
+    if( pIter->pBtree!=p && pIter->iTable==iTab && pIter->eLock!=eLock ){
+      sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
+      if( eLock==WRITE_LOCK ){
+        assert( p==pBt->pWriter );
+        pBt->btsFlags |= BTS_PENDING;
       }
+      return SQLITE_LOCKED_SHAREDCACHE;
     }
   }
   return SQLITE_OK;
@@ -36397,10 +48206,19 @@ static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){
 ** by Btree handle p. Parameter eLock must be either READ_LOCK or 
 ** WRITE_LOCK.
 **
-** SQLITE_OK is returned if the lock is added successfully. SQLITE_BUSY and
-** SQLITE_NOMEM may also be returned.
+** This function assumes the following:
+**
+**   (a) The specified Btree object p is connected to a sharable
+**       database (one with the BtShared.sharable flag set), and
+**
+**   (b) No other Btree objects hold a lock that conflicts
+**       with the requested lock (i.e. querySharedCacheTableLock() has
+**       already been called and returned SQLITE_OK).
+**
+** SQLITE_OK is returned if the lock is added successfully. SQLITE_NOMEM 
+** is returned if a malloc attempt fails.
 */
-static int lockTable(Btree *p, Pgno iTable, u8 eLock){
+static int setSharedCacheTableLock(Btree *p, Pgno iTable, u8 eLock){
   BtShared *pBt = p->pBt;
   BtLock *pLock = 0;
   BtLock *pIter;
@@ -36409,25 +48227,16 @@ static int lockTable(Btree *p, Pgno iTable, u8 eLock){
   assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
   assert( p->db!=0 );
 
-  /* This is a no-op if the shared-cache is not enabled */
-  if( !p->sharable ){
-    return SQLITE_OK;
-  }
+  /* A connection with the read-uncommitted flag set will never try to
+  ** obtain a read-lock using this function. The only read-lock obtained
+  ** by a connection in read-uncommitted mode is on the sqlite_master 
+  ** table, and that lock is obtained in BtreeBeginTrans().  */
+  assert( 0==(p->db->flags&SQLITE_ReadUncommitted) || eLock==WRITE_LOCK );
 
-  assert( SQLITE_OK==queryTableLock(p, iTable, eLock) );
-
-  /* If the read-uncommitted flag is set and a read-lock is requested,
-  ** return early without adding an entry to the BtShared.pLock list. See
-  ** comment in function queryTableLock() for more info on handling 
-  ** the ReadUncommitted flag.
-  */
-  if( 
-    (p->db->flags&SQLITE_ReadUncommitted) && 
-    (eLock==READ_LOCK) &&
-    iTable!=MASTER_ROOT
-  ){
-    return SQLITE_OK;
-  }
+  /* This function should only be called on a sharable b-tree after it 
+  ** has been determined that no other b-tree holds a conflicting lock.  */
+  assert( p->sharable );
+  assert( SQLITE_OK==querySharedCacheTableLock(p, iTable, eLock) );
 
   /* First search the list for an existing lock on this table. */
   for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
@@ -36466,39 +48275,80 @@ static int lockTable(Btree *p, Pgno iTable, u8 eLock){
 
 #ifndef SQLITE_OMIT_SHARED_CACHE
 /*
-** Release all the table locks (locks obtained via calls to the lockTable()
-** procedure) held by Btree handle p.
+** Release all the table locks (locks obtained via calls to
+** the setSharedCacheTableLock() procedure) held by Btree object p.
+**
+** This function assumes that Btree p has an open read or write 
+** transaction. If it does not, then the BTS_PENDING flag
+** may be incorrectly cleared.
 */
-static void unlockAllTables(Btree *p){
+static void clearAllSharedCacheTableLocks(Btree *p){
   BtShared *pBt = p->pBt;
   BtLock **ppIter = &pBt->pLock;
 
   assert( sqlite3BtreeHoldsMutex(p) );
   assert( p->sharable || 0==*ppIter );
+  assert( p->inTrans>0 );
 
   while( *ppIter ){
     BtLock *pLock = *ppIter;
-    assert( pBt->pExclusive==0 || pBt->pExclusive==pLock->pBtree );
+    assert( (pBt->btsFlags & BTS_EXCLUSIVE)==0 || pBt->pWriter==pLock->pBtree );
+    assert( pLock->pBtree->inTrans>=pLock->eLock );
     if( pLock->pBtree==p ){
       *ppIter = pLock->pNext;
-      sqlite3_free(pLock);
+      assert( pLock->iTable!=1 || pLock==&p->lock );
+      if( pLock->iTable!=1 ){
+        sqlite3_free(pLock);
+      }
     }else{
       ppIter = &pLock->pNext;
     }
   }
 
-  if( pBt->pExclusive==p ){
-    pBt->pExclusive = 0;
+  assert( (pBt->btsFlags & BTS_PENDING)==0 || pBt->pWriter );
+  if( pBt->pWriter==p ){
+    pBt->pWriter = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
+  }else if( pBt->nTransaction==2 ){
+    /* This function is called when Btree p is concluding its 
+    ** transaction. If there currently exists a writer, and p is not
+    ** that writer, then the number of locks held by connections other
+    ** than the writer must be about to drop to zero. In this case
+    ** set the BTS_PENDING flag to 0.
+    **
+    ** If there is not currently a writer, then BTS_PENDING must
+    ** be zero already. So this next line is harmless in that case.
+    */
+    pBt->btsFlags &= ~BTS_PENDING;
   }
 }
+
+/*
+** This function changes all write-locks held by Btree p into read-locks.
+*/
+static void downgradeAllSharedCacheTableLocks(Btree *p){
+  BtShared *pBt = p->pBt;
+  if( pBt->pWriter==p ){
+    BtLock *pLock;
+    pBt->pWriter = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
+    for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
+      assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
+      pLock->eLock = READ_LOCK;
+    }
+  }
+}
+
 #endif /* SQLITE_OMIT_SHARED_CACHE */
 
 static void releasePage(MemPage *pPage);  /* Forward reference */
 
 /*
-** Verify that the cursor holds a mutex on the BtShared
+***** This routine is used inside of assert() only ****
+**
+** Verify that the cursor holds the mutex on its BtShared
 */
-#ifndef NDEBUG
+#ifdef SQLITE_DEBUG
 static int cursorHoldsMutex(BtCursor *p){
   return sqlite3_mutex_held(p->pBt->mutex);
 }
@@ -36526,14 +48376,119 @@ static void invalidateAllOverflowCache(BtShared *pBt){
     invalidateOverflowCache(p);
   }
 }
+
+/*
+** This function is called before modifying the contents of a table
+** to invalidate any incrblob cursors that are open on the
+** row or one of the rows being modified.
+**
+** If argument isClearTable is true, then the entire contents of the
+** table is about to be deleted. In this case invalidate all incrblob
+** cursors open on any row within the table with root-page pgnoRoot.
+**
+** Otherwise, if argument isClearTable is false, then the row with
+** rowid iRow is being replaced or deleted. In this case invalidate
+** only those incrblob cursors open on that specific row.
+*/
+static void invalidateIncrblobCursors(
+  Btree *pBtree,          /* The database file to check */
+  i64 iRow,               /* The rowid that might be changing */
+  int isClearTable        /* True if all rows are being deleted */
+){
+  BtCursor *p;
+  BtShared *pBt = pBtree->pBt;
+  assert( sqlite3BtreeHoldsMutex(pBtree) );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    if( p->isIncrblobHandle && (isClearTable || p->info.nKey==iRow) ){
+      p->eState = CURSOR_INVALID;
+    }
+  }
+}
+
 #else
+  /* Stub functions when INCRBLOB is omitted */
   #define invalidateOverflowCache(x)
   #define invalidateAllOverflowCache(x)
-#endif
+  #define invalidateIncrblobCursors(x,y,z)
+#endif /* SQLITE_OMIT_INCRBLOB */
+
+/*
+** Set bit pgno of the BtShared.pHasContent bitvec. This is called 
+** when a page that previously contained data becomes a free-list leaf 
+** page.
+**
+** The BtShared.pHasContent bitvec exists to work around an obscure
+** bug caused by the interaction of two useful IO optimizations surrounding
+** free-list leaf pages:
+**
+**   1) When all data is deleted from a page and the page becomes
+**      a free-list leaf page, the page is not written to the database
+**      (as free-list leaf pages contain no meaningful data). Sometimes
+**      such a page is not even journalled (as it will not be modified,
+**      why bother journalling it?).
+**
+**   2) When a free-list leaf page is reused, its content is not read
+**      from the database or written to the journal file (why should it
+**      be, if it is not at all meaningful?).
+**
+** By themselves, these optimizations work fine and provide a handy
+** performance boost to bulk delete or insert operations. However, if
+** a page is moved to the free-list and then reused within the same
+** transaction, a problem comes up. If the page is not journalled when
+** it is moved to the free-list and it is also not journalled when it
+** is extracted from the free-list and reused, then the original data
+** may be lost. In the event of a rollback, it may not be possible
+** to restore the database to its original configuration.
+**
+** The solution is the BtShared.pHasContent bitvec. Whenever a page is 
+** moved to become a free-list leaf page, the corresponding bit is
+** set in the bitvec. Whenever a leaf page is extracted from the free-list,
+** optimization 2 above is omitted if the corresponding bit is already
+** set in BtShared.pHasContent. The contents of the bitvec are cleared
+** at the end of every transaction.
+*/
+static int btreeSetHasContent(BtShared *pBt, Pgno pgno){
+  int rc = SQLITE_OK;
+  if( !pBt->pHasContent ){
+    assert( pgno<=pBt->nPage );
+    pBt->pHasContent = sqlite3BitvecCreate(pBt->nPage);
+    if( !pBt->pHasContent ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+  if( rc==SQLITE_OK && pgno<=sqlite3BitvecSize(pBt->pHasContent) ){
+    rc = sqlite3BitvecSet(pBt->pHasContent, pgno);
+  }
+  return rc;
+}
+
+/*
+** Query the BtShared.pHasContent vector.
+**
+** This function is called when a free-list leaf page is removed from the
+** free-list for reuse. It returns false if it is safe to retrieve the
+** page from the pager layer with the 'no-content' flag set. True otherwise.
+*/
+static int btreeGetHasContent(BtShared *pBt, Pgno pgno){
+  Bitvec *p = pBt->pHasContent;
+  return (p && (pgno>sqlite3BitvecSize(p) || sqlite3BitvecTest(p, pgno)));
+}
+
+/*
+** Clear (destroy) the BtShared.pHasContent bitvec. This should be
+** invoked at the conclusion of each write-transaction.
+*/
+static void btreeClearHasContent(BtShared *pBt){
+  sqlite3BitvecDestroy(pBt->pHasContent);
+  pBt->pHasContent = 0;
+}
 
 /*
 ** Save the current cursor position in the variables BtCursor.nKey 
 ** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
+**
+** The caller must ensure that the cursor is valid (has eState==CURSOR_VALID)
+** prior to calling this routine.  
 */
 static int saveCursorPosition(BtCursor *pCur){
   int rc;
@@ -36543,6 +48498,7 @@ static int saveCursorPosition(BtCursor *pCur){
   assert( cursorHoldsMutex(pCur) );
 
   rc = sqlite3BtreeKeySize(pCur, &pCur->nKey);
+  assert( rc==SQLITE_OK );  /* KeySize() cannot fail */
 
   /* If this is an intKey table, then the above call to BtreeKeySize()
   ** stores the integer key in pCur->nKey. In this case this value is
@@ -36550,7 +48506,7 @@ static int saveCursorPosition(BtCursor *pCur){
   ** table, then malloc space for and store the pCur->nKey bytes of key 
   ** data.
   */
-  if( rc==SQLITE_OK && 0==pCur->apPage[0]->intKey){
+  if( 0==pCur->apPage[0]->intKey ){
     void *pKey = sqlite3Malloc( (int)pCur->nKey );
     if( pKey ){
       rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
@@ -36580,8 +48536,8 @@ static int saveCursorPosition(BtCursor *pCur){
 }
 
 /*
-** Save the positions of all cursors except pExcept open on the table 
-** with root-page iRoot. Usually, this is called just before cursor
+** Save the positions of all cursors (except pExcept) that are open on
+** the table  with root-page iRoot. Usually, this is called just before cursor
 ** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
 */
 static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
@@ -36610,6 +48566,40 @@ SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *pCur){
   pCur->eState = CURSOR_INVALID;
 }
 
+/*
+** In this version of BtreeMoveto, pKey is a packed index record
+** such as is generated by the OP_MakeRecord opcode.  Unpack the
+** record and then call BtreeMovetoUnpacked() to do the work.
+*/
+static int btreeMoveto(
+  BtCursor *pCur,     /* Cursor open on the btree to be searched */
+  const void *pKey,   /* Packed key if the btree is an index */
+  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
+  int bias,           /* Bias search to the high end */
+  int *pRes           /* Write search results here */
+){
+  int rc;                    /* Status code */
+  UnpackedRecord *pIdxKey;   /* Unpacked index key */
+  char aSpace[150];          /* Temp space for pIdxKey - to avoid a malloc */
+  char *pFree = 0;
+
+  if( pKey ){
+    assert( nKey==(i64)(int)nKey );
+    pIdxKey = sqlite3VdbeAllocUnpackedRecord(
+        pCur->pKeyInfo, aSpace, sizeof(aSpace), &pFree
+    );
+    if( pIdxKey==0 ) return SQLITE_NOMEM;
+    sqlite3VdbeRecordUnpack(pCur->pKeyInfo, (int)nKey, pKey, pIdxKey);
+  }else{
+    pIdxKey = 0;
+  }
+  rc = sqlite3BtreeMovetoUnpacked(pCur, pIdxKey, nKey, bias, pRes);
+  if( pFree ){
+    sqlite3DbFree(pCur->pKeyInfo->db, pFree);
+  }
+  return rc;
+}
+
 /*
 ** Restore the cursor to the position it was in (or as close to as possible)
 ** when saveCursorPosition() was called. Note that this call deletes the 
@@ -36617,15 +48607,15 @@ SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *pCur){
 ** at most one effective restoreCursorPosition() call after each 
 ** saveCursorPosition().
 */
-SQLITE_PRIVATE int sqlite3BtreeRestoreCursorPosition(BtCursor *pCur){
+static int btreeRestoreCursorPosition(BtCursor *pCur){
   int rc;
   assert( cursorHoldsMutex(pCur) );
   assert( pCur->eState>=CURSOR_REQUIRESEEK );
   if( pCur->eState==CURSOR_FAULT ){
-    return pCur->skip;
+    return pCur->skipNext;
   }
   pCur->eState = CURSOR_INVALID;
-  rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, 0, &pCur->skip);
+  rc = btreeMoveto(pCur, pCur->pKey, pCur->nKey, 0, &pCur->skipNext);
   if( rc==SQLITE_OK ){
     sqlite3_free(pCur->pKey);
     pCur->pKey = 0;
@@ -36636,7 +48626,7 @@ SQLITE_PRIVATE int sqlite3BtreeRestoreCursorPosition(BtCursor *pCur){
 
 #define restoreCursorPosition(p) \
   (p->eState>=CURSOR_REQUIRESEEK ? \
-         sqlite3BtreeRestoreCursorPosition(p) : \
+         btreeRestoreCursorPosition(p) : \
          SQLITE_OK)
 
 /*
@@ -36655,7 +48645,7 @@ SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor *pCur, int *pHasMoved){
     *pHasMoved = 1;
     return rc;
   }
-  if( pCur->eState!=CURSOR_VALID || pCur->skip!=0 ){
+  if( pCur->eState!=CURSOR_VALID || pCur->skipNext!=0 ){
     *pHasMoved = 1;
   }else{
     *pHasMoved = 0;
@@ -36668,11 +48658,16 @@ SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor *pCur, int *pHasMoved){
 ** Given a page number of a regular database page, return the page
 ** number for the pointer-map page that contains the entry for the
 ** input page number.
+**
+** Return 0 (not a valid page) for pgno==1 since there is
+** no pointer map associated with page 1.  The integrity_check logic
+** requires that ptrmapPageno(*,1)!=1.
 */
 static Pgno ptrmapPageno(BtShared *pBt, Pgno pgno){
   int nPagesPerMapPage;
   Pgno iPtrMap, ret;
   assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pgno<2 ) return 0;
   nPagesPerMapPage = (pBt->usableSize/5)+1;
   iPtrMap = (pgno-2)/nPagesPerMapPage;
   ret = (iPtrMap*nPagesPerMapPage) + 2; 
@@ -36687,14 +48682,19 @@ static Pgno ptrmapPageno(BtShared *pBt, Pgno pgno){
 **
 ** This routine updates the pointer map entry for page number 'key'
 ** so that it maps to type 'eType' and parent page number 'pgno'.
-** An error code is returned if something goes wrong, otherwise SQLITE_OK.
+**
+** If *pRC is initially non-zero (non-SQLITE_OK) then this routine is
+** a no-op.  If an error occurs, the appropriate error code is written
+** into *pRC.
 */
-static int ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent){
+static void ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent, int *pRC){
   DbPage *pDbPage;  /* The pointer map page */
   u8 *pPtrmap;      /* The pointer map data */
   Pgno iPtrmap;     /* The pointer map page number */
   int offset;       /* Offset in pointer map page */
-  int rc;
+  int rc;           /* Return code from subfunctions */
+
+  if( *pRC ) return;
 
   assert( sqlite3_mutex_held(pBt->mutex) );
   /* The master-journal page number must never be used as a pointer map page */
@@ -36702,27 +48702,34 @@ static int ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent){
 
   assert( pBt->autoVacuum );
   if( key==0 ){
-    return SQLITE_CORRUPT_BKPT;
+    *pRC = SQLITE_CORRUPT_BKPT;
+    return;
   }
   iPtrmap = PTRMAP_PAGENO(pBt, key);
   rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage);
   if( rc!=SQLITE_OK ){
-    return rc;
+    *pRC = rc;
+    return;
   }
   offset = PTRMAP_PTROFFSET(iPtrmap, key);
+  if( offset<0 ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    goto ptrmap_exit;
+  }
+  assert( offset <= (int)pBt->usableSize-5 );
   pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
 
   if( eType!=pPtrmap[offset] || get4byte(&pPtrmap[offset+1])!=parent ){
     TRACE(("PTRMAP_UPDATE: %d->(%d,%d)\n", key, eType, parent));
-    rc = sqlite3PagerWrite(pDbPage);
+    *pRC= rc = sqlite3PagerWrite(pDbPage);
     if( rc==SQLITE_OK ){
       pPtrmap[offset] = eType;
       put4byte(&pPtrmap[offset+1], parent);
     }
   }
 
+ptrmap_exit:
   sqlite3PagerUnref(pDbPage);
-  return rc;
 }
 
 /*
@@ -36749,6 +48756,11 @@ static int ptrmapGet(BtShared *pBt, Pgno key, u8 *pEType, Pgno *pPgno){
   pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
 
   offset = PTRMAP_PTROFFSET(iPtrmap, key);
+  if( offset<0 ){
+    sqlite3PagerUnref(pDbPage);
+    return SQLITE_CORRUPT_BKPT;
+  }
+  assert( offset <= (int)pBt->usableSize-5 );
   assert( pEType!=0 );
   *pEType = pPtrmap[offset];
   if( pPgno ) *pPgno = get4byte(&pPtrmap[offset+1]);
@@ -36759,9 +48771,9 @@ static int ptrmapGet(BtShared *pBt, Pgno key, u8 *pEType, Pgno *pPgno){
 }
 
 #else /* if defined SQLITE_OMIT_AUTOVACUUM */
-  #define ptrmapPut(w,x,y,z) SQLITE_OK
+  #define ptrmapPut(w,x,y,z,rc)
   #define ptrmapGet(w,x,y,z) SQLITE_OK
-  #define ptrmapPutOvfl(y,z) SQLITE_OK
+  #define ptrmapPutOvflPtr(x, y, rc)
 #endif
 
 /*
@@ -36772,23 +48784,23 @@ static int ptrmapGet(BtShared *pBt, Pgno key, u8 *pEType, Pgno *pPgno){
 ** This routine works only for pages that do not contain overflow cells.
 */
 #define findCell(P,I) \
-  ((P)->aData + ((P)->maskPage & get2byte(&(P)->aData[(P)->cellOffset+2*(I)])))
+  ((P)->aData + ((P)->maskPage & get2byte(&(P)->aCellIdx[2*(I)])))
+#define findCellv2(D,M,O,I) (D+(M&get2byte(D+(O+2*(I)))))
+
 
 /*
 ** This a more complex version of findCell() that works for
-** pages that do contain overflow cells.  See insert
+** pages that do contain overflow cells.
 */
 static u8 *findOverflowCell(MemPage *pPage, int iCell){
   int i;
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
   for(i=pPage->nOverflow-1; i>=0; i--){
     int k;
-    struct _OvflCell *pOvfl;
-    pOvfl = &pPage->aOvfl[i];
-    k = pOvfl->idx;
+    k = pPage->aiOvfl[i];
     if( k<=iCell ){
       if( k==iCell ){
-        return pOvfl->pCell;
+        return pPage->apOvfl[i];
       }
       iCell--;
     }
@@ -36798,14 +48810,14 @@ static u8 *findOverflowCell(MemPage *pPage, int iCell){
 
 /*
 ** Parse a cell content block and fill in the CellInfo structure.  There
-** are two versions of this function.  sqlite3BtreeParseCell() takes a 
-** cell index as the second argument and sqlite3BtreeParseCellPtr() 
+** are two versions of this function.  btreeParseCell() takes a 
+** cell index as the second argument and btreeParseCellPtr() 
 ** takes a pointer to the body of the cell as its second argument.
 **
 ** Within this file, the parseCell() macro can be called instead of
-** sqlite3BtreeParseCellPtr(). Using some compilers, this will be faster.
+** btreeParseCellPtr(). Using some compilers, this will be faster.
 */
-SQLITE_PRIVATE void sqlite3BtreeParseCellPtr(
+static void btreeParseCellPtr(
   MemPage *pPage,         /* Page containing the cell */
   u8 *pCell,              /* Pointer to the cell text. */
   CellInfo *pInfo         /* Fill in this structure */
@@ -36834,18 +48846,15 @@ SQLITE_PRIVATE void sqlite3BtreeParseCellPtr(
   }
   pInfo->nPayload = nPayload;
   pInfo->nHeader = n;
+  testcase( nPayload==pPage->maxLocal );
+  testcase( nPayload==pPage->maxLocal+1 );
   if( likely(nPayload<=pPage->maxLocal) ){
     /* This is the (easy) common case where the entire payload fits
     ** on the local page.  No overflow is required.
     */
-    int nSize;          /* Total size of cell content in bytes */
-    nSize = nPayload + n;
+    if( (pInfo->nSize = (u16)(n+nPayload))<4 ) pInfo->nSize = 4;
     pInfo->nLocal = (u16)nPayload;
     pInfo->iOverflow = 0;
-    if( (nSize & ~3)==0 ){
-      nSize = 4;        /* Minimum cell size is 4 */
-    }
-    pInfo->nSize = (u16)nSize;
   }else{
     /* If the payload will not fit completely on the local page, we have
     ** to decide how much to store locally and how much to spill onto
@@ -36863,6 +48872,8 @@ SQLITE_PRIVATE void sqlite3BtreeParseCellPtr(
     minLocal = pPage->minLocal;
     maxLocal = pPage->maxLocal;
     surplus = minLocal + (nPayload - minLocal)%(pPage->pBt->usableSize - 4);
+    testcase( surplus==maxLocal );
+    testcase( surplus==maxLocal+1 );
     if( surplus <= maxLocal ){
       pInfo->nLocal = (u16)surplus;
     }else{
@@ -36873,8 +48884,8 @@ SQLITE_PRIVATE void sqlite3BtreeParseCellPtr(
   }
 }
 #define parseCell(pPage, iCell, pInfo) \
-  sqlite3BtreeParseCellPtr((pPage), findCell((pPage), (iCell)), (pInfo))
-SQLITE_PRIVATE void sqlite3BtreeParseCell(
+  btreeParseCellPtr((pPage), findCell((pPage), (iCell)), (pInfo))
+static void btreeParseCell(
   MemPage *pPage,         /* Page containing the cell */
   int iCell,              /* The cell index.  First cell is 0 */
   CellInfo *pInfo         /* Fill in this structure */
@@ -36888,18 +48899,66 @@ SQLITE_PRIVATE void sqlite3BtreeParseCell(
 ** data header and the local payload, but not any overflow page or
 ** the space used by the cell pointer.
 */
-#ifndef NDEBUG
+static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
+  u8 *pIter = &pCell[pPage->childPtrSize];
+  u32 nSize;
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  btreeParseCellPtr(pPage, pCell, &debuginfo);
+#endif
+
+  if( pPage->intKey ){
+    u8 *pEnd;
+    if( pPage->hasData ){
+      pIter += getVarint32(pIter, nSize);
+    }else{
+      nSize = 0;
+    }
+
+    /* pIter now points at the 64-bit integer key value, a variable length 
+    ** integer. The following block moves pIter to point at the first byte
+    ** past the end of the key value. */
+    pEnd = &pIter[9];
+    while( (*pIter++)&0x80 && pIter<pEnd );
+  }else{
+    pIter += getVarint32(pIter, nSize);
+  }
+
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==pPage->maxLocal+1 );
+  if( nSize>pPage->maxLocal ){
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4;
+  }
+  nSize += (u32)(pIter - pCell);
+
+  /* The minimum size of any cell is 4 bytes. */
+  if( nSize<4 ){
+    nSize = 4;
+  }
+
+  assert( nSize==debuginfo.nSize );
+  return (u16)nSize;
+}
+
+#ifdef SQLITE_DEBUG
+/* This variation on cellSizePtr() is used inside of assert() statements
+** only. */
 static u16 cellSize(MemPage *pPage, int iCell){
-  CellInfo info;
-  sqlite3BtreeParseCell(pPage, iCell, &info);
-  return info.nSize;
+  return cellSizePtr(pPage, findCell(pPage, iCell));
 }
 #endif
-static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
-  CellInfo info;
-  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
-  return info.nSize;
-}
 
 #ifndef SQLITE_OMIT_AUTOVACUUM
 /*
@@ -36907,27 +48966,16 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
 ** to an overflow page, insert an entry into the pointer-map
 ** for the overflow page.
 */
-static int ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell){
+static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
   CellInfo info;
+  if( *pRC ) return;
   assert( pCell!=0 );
-  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+  btreeParseCellPtr(pPage, pCell, &info);
   assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
-  if( (info.nData+(pPage->intKey?0:info.nKey))>info.nLocal ){
+  if( info.iOverflow ){
     Pgno ovfl = get4byte(&pCell[info.iOverflow]);
-    return ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno);
+    ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
   }
-  return SQLITE_OK;
-}
-/*
-** If the cell with index iCell on page pPage contains a pointer
-** to an overflow page, insert an entry into the pointer-map
-** for the overflow page.
-*/
-static int ptrmapPutOvfl(MemPage *pPage, int iCell){
-  u8 *pCell;
-  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  pCell = findOverflowCell(pPage, iCell);
-  return ptrmapPutOvflPtr(pPage, pCell);
 }
 #endif
 
@@ -36941,7 +48989,6 @@ static int ptrmapPutOvfl(MemPage *pPage, int iCell){
 static int defragmentPage(MemPage *pPage){
   int i;                     /* Loop counter */
   int pc;                    /* Address of a i-th cell */
-  int addr;                  /* Offset of first byte after cell pointer array */
   int hdr;                   /* Offset to the page header */
   int size;                  /* Size of a cell */
   int usableSize;            /* Number of usable bytes on a page */
@@ -36950,6 +48997,9 @@ static int defragmentPage(MemPage *pPage){
   int nCell;                 /* Number of cells on the page */
   unsigned char *data;       /* The page data */
   unsigned char *temp;       /* Temp area for cell content */
+  int iCellFirst;            /* First allowable cell index */
+  int iCellLast;             /* Last possible cell index */
+
 
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
   assert( pPage->pBt!=0 );
@@ -36966,104 +49016,155 @@ static int defragmentPage(MemPage *pPage){
   cbrk = get2byte(&data[hdr+5]);
   memcpy(&temp[cbrk], &data[cbrk], usableSize - cbrk);
   cbrk = usableSize;
+  iCellFirst = cellOffset + 2*nCell;
+  iCellLast = usableSize - 4;
   for(i=0; i<nCell; i++){
     u8 *pAddr;     /* The i-th cell pointer */
     pAddr = &data[cellOffset + i*2];
     pc = get2byte(pAddr);
-    if( pc>=usableSize ){
+    testcase( pc==iCellFirst );
+    testcase( pc==iCellLast );
+#if !defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
+    /* These conditions have already been verified in btreeInitPage()
+    ** if SQLITE_ENABLE_OVERSIZE_CELL_CHECK is defined 
+    */
+    if( pc<iCellFirst || pc>iCellLast ){
       return SQLITE_CORRUPT_BKPT;
     }
+#endif
+    assert( pc>=iCellFirst && pc<=iCellLast );
     size = cellSizePtr(pPage, &temp[pc]);
     cbrk -= size;
-    if( cbrk<cellOffset+2*nCell || pc+size>usableSize ){
+#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
+    if( cbrk<iCellFirst ){
       return SQLITE_CORRUPT_BKPT;
     }
-    assert( cbrk+size<=usableSize && cbrk>=0 );
+#else
+    if( cbrk<iCellFirst || pc+size>usableSize ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+#endif
+    assert( cbrk+size<=usableSize && cbrk>=iCellFirst );
+    testcase( cbrk+size==usableSize );
+    testcase( pc+size==usableSize );
     memcpy(&data[cbrk], &temp[pc], size);
     put2byte(pAddr, cbrk);
   }
-  assert( cbrk>=cellOffset+2*nCell );
+  assert( cbrk>=iCellFirst );
   put2byte(&data[hdr+5], cbrk);
   data[hdr+1] = 0;
   data[hdr+2] = 0;
   data[hdr+7] = 0;
-  addr = cellOffset+2*nCell;
-  memset(&data[addr], 0, cbrk-addr);
+  memset(&data[iCellFirst], 0, cbrk-iCellFirst);
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-  if( cbrk-addr!=pPage->nFree ){
+  if( cbrk-iCellFirst!=pPage->nFree ){
     return SQLITE_CORRUPT_BKPT;
   }
   return SQLITE_OK;
 }
 
 /*
-** Allocate nByte bytes of space on a page.
+** Allocate nByte bytes of space from within the B-Tree page passed
+** as the first argument. Write into *pIdx the index into pPage->aData[]
+** of the first byte of allocated space. Return either SQLITE_OK or
+** an error code (usually SQLITE_CORRUPT).
 **
-** Return the index into pPage->aData[] of the first byte of
-** the new allocation.  The caller guarantees that there is enough
-** space.  This routine will never fail.
-**
-** If the page contains nBytes of free space but does not contain
-** nBytes of contiguous free space, then this routine automatically
-** calls defragementPage() to consolidate all free space before 
-** allocating the new chunk.
+** The caller guarantees that there is sufficient space to make the
+** allocation.  This routine might need to defragment in order to bring
+** all the space together, however.  This routine will avoid using
+** the first two bytes past the cell pointer area since presumably this
+** allocation is being made in order to insert a new cell, so we will
+** also end up needing a new cell pointer.
 */
-static int allocateSpace(MemPage *pPage, int nByte){
-  int addr, pc, hdr;
-  int size;
-  int nFrag;
-  int top;
-  int nCell;
-  int cellOffset;
-  unsigned char *data;
+static int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
+  const int hdr = pPage->hdrOffset;    /* Local cache of pPage->hdrOffset */
+  u8 * const data = pPage->aData;      /* Local cache of pPage->aData */
+  int nFrag;                           /* Number of fragmented bytes on pPage */
+  int top;                             /* First byte of cell content area */
+  int gap;        /* First byte of gap between cell pointers and cell content */
+  int rc;         /* Integer return code */
+  int usableSize; /* Usable size of the page */
   
-  data = pPage->aData;
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
   assert( pPage->pBt );
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
   assert( nByte>=0 );  /* Minimum cell size is 4 */
   assert( pPage->nFree>=nByte );
   assert( pPage->nOverflow==0 );
-  pPage->nFree -= (u16)nByte;
-  hdr = pPage->hdrOffset;
+  usableSize = pPage->pBt->usableSize;
+  assert( nByte < usableSize-8 );
 
   nFrag = data[hdr+7];
-  if( nFrag<60 ){
-    /* Search the freelist looking for a slot big enough to satisfy the
-    ** space request. */
-    addr = hdr+1;
-    while( (pc = get2byte(&data[addr]))>0 ){
+  assert( pPage->cellOffset == hdr + 12 - 4*pPage->leaf );
+  gap = pPage->cellOffset + 2*pPage->nCell;
+  top = get2byteNotZero(&data[hdr+5]);
+  if( gap>top ) return SQLITE_CORRUPT_BKPT;
+  testcase( gap+2==top );
+  testcase( gap+1==top );
+  testcase( gap==top );
+
+  if( nFrag>=60 ){
+    /* Always defragment highly fragmented pages */
+    rc = defragmentPage(pPage);
+    if( rc ) return rc;
+    top = get2byteNotZero(&data[hdr+5]);
+  }else if( gap+2<=top ){
+    /* Search the freelist looking for a free slot big enough to satisfy 
+    ** the request. The allocation is made from the first free slot in 
+    ** the list that is large enough to accomadate it.
+    */
+    int pc, addr;
+    for(addr=hdr+1; (pc = get2byte(&data[addr]))>0; addr=pc){
+      int size;            /* Size of the free slot */
+      if( pc>usableSize-4 || pc<addr+4 ){
+        return SQLITE_CORRUPT_BKPT;
+      }
       size = get2byte(&data[pc+2]);
       if( size>=nByte ){
         int x = size - nByte;
-        if( size<nByte+4 ){
+        testcase( x==4 );
+        testcase( x==3 );
+        if( x<4 ){
+          /* Remove the slot from the free-list. Update the number of
+          ** fragmented bytes within the page. */
           memcpy(&data[addr], &data[pc], 2);
           data[hdr+7] = (u8)(nFrag + x);
-          return pc;
+        }else if( size+pc > usableSize ){
+          return SQLITE_CORRUPT_BKPT;
         }else{
+          /* The slot remains on the free-list. Reduce its size to account
+          ** for the portion used by the new allocation. */
           put2byte(&data[pc+2], x);
-          return pc + x;
         }
+        *pIdx = pc + x;
+        return SQLITE_OK;
       }
-      addr = pc;
     }
   }
 
-  /* Allocate memory from the gap in between the cell pointer array
-  ** and the cell content area.
+  /* Check to make sure there is enough space in the gap to satisfy
+  ** the allocation.  If not, defragment.
   */
-  top = get2byte(&data[hdr+5]);
-  nCell = get2byte(&data[hdr+3]);
-  cellOffset = pPage->cellOffset;
-  if( nFrag>=60 || cellOffset + 2*nCell > top - nByte ){
-    defragmentPage(pPage);
-    top = get2byte(&data[hdr+5]);
+  testcase( gap+2+nByte==top );
+  if( gap+2+nByte>top ){
+    rc = defragmentPage(pPage);
+    if( rc ) return rc;
+    top = get2byteNotZero(&data[hdr+5]);
+    assert( gap+nByte<=top );
   }
+
+
+  /* Allocate memory from the gap in between the cell pointer array
+  ** and the cell content area.  The btreeInitPage() call has already
+  ** validated the freelist.  Given that the freelist is valid, there
+  ** is no way that the allocation can extend off the end of the page.
+  ** The assert() below verifies the previous sentence.
+  */
   top -= nByte;
-  assert( cellOffset + 2*nCell <= top );
   put2byte(&data[hdr+5], top);
-  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-  return top;
+  assert( top+nByte <= (int)pPage->pBt->usableSize );
+  *pIdx = top;
+  return SQLITE_OK;
 }
 
 /*
@@ -37076,54 +49177,64 @@ static int allocateSpace(MemPage *pPage, int nByte){
 */
 static int freeSpace(MemPage *pPage, int start, int size){
   int addr, pbegin, hdr;
+  int iLast;                        /* Largest possible freeblock offset */
   unsigned char *data = pPage->aData;
 
   assert( pPage->pBt!=0 );
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-  assert( start>=pPage->hdrOffset+6+(pPage->leaf?0:4) );
-  assert( (start + size)<=pPage->pBt->usableSize );
+  assert( start>=pPage->hdrOffset+6+pPage->childPtrSize );
+  assert( (start + size) <= (int)pPage->pBt->usableSize );
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
   assert( size>=0 );   /* Minimum cell size is 4 */
 
-#ifdef SQLITE_SECURE_DELETE
-  /* Overwrite deleted information with zeros when the SECURE_DELETE 
-  ** option is enabled at compile-time */
-  memset(&data[start], 0, size);
-#endif
+  if( pPage->pBt->btsFlags & BTS_SECURE_DELETE ){
+    /* Overwrite deleted information with zeros when the secure_delete
+    ** option is enabled */
+    memset(&data[start], 0, size);
+  }
 
-  /* Add the space back into the linked list of freeblocks */
+  /* Add the space back into the linked list of freeblocks.  Note that
+  ** even though the freeblock list was checked by btreeInitPage(),
+  ** btreeInitPage() did not detect overlapping cells or
+  ** freeblocks that overlapped cells.   Nor does it detect when the
+  ** cell content area exceeds the value in the page header.  If these
+  ** situations arise, then subsequent insert operations might corrupt
+  ** the freelist.  So we do need to check for corruption while scanning
+  ** the freelist.
+  */
   hdr = pPage->hdrOffset;
   addr = hdr + 1;
+  iLast = pPage->pBt->usableSize - 4;
+  assert( start<=iLast );
   while( (pbegin = get2byte(&data[addr]))<start && pbegin>0 ){
-    assert( pbegin<=pPage->pBt->usableSize-4 );
-    if( pbegin<=addr ) {
+    if( pbegin<addr+4 ){
       return SQLITE_CORRUPT_BKPT;
     }
     addr = pbegin;
   }
-  if ( pbegin>pPage->pBt->usableSize-4 ) {
+  if( pbegin>iLast ){
     return SQLITE_CORRUPT_BKPT;
   }
   assert( pbegin>addr || pbegin==0 );
   put2byte(&data[addr], start);
   put2byte(&data[start], pbegin);
   put2byte(&data[start+2], size);
-  pPage->nFree += (u16)size;
+  pPage->nFree = pPage->nFree + (u16)size;
 
   /* Coalesce adjacent free blocks */
-  addr = pPage->hdrOffset + 1;
+  addr = hdr + 1;
   while( (pbegin = get2byte(&data[addr]))>0 ){
     int pnext, psize, x;
     assert( pbegin>addr );
-    assert( pbegin<=pPage->pBt->usableSize-4 );
+    assert( pbegin <= (int)pPage->pBt->usableSize-4 );
     pnext = get2byte(&data[pbegin]);
     psize = get2byte(&data[pbegin+2]);
     if( pbegin + psize + 3 >= pnext && pnext>0 ){
       int frag = pnext - (pbegin+psize);
-      if( (frag<0) || (frag>(int)data[pPage->hdrOffset+7]) ){
+      if( (frag<0) || (frag>(int)data[hdr+7]) ){
         return SQLITE_CORRUPT_BKPT;
       }
-      data[pPage->hdrOffset+7] -= (u8)frag;
+      data[hdr+7] -= (u8)frag;
       x = get2byte(&data[pnext]);
       put2byte(&data[pbegin], x);
       x = pnext + get2byte(&data[pnext+2]) - pbegin;
@@ -37179,6 +49290,7 @@ static int decodeFlags(MemPage *pPage, int flagByte){
   }else{
     return SQLITE_CORRUPT_BKPT;
   }
+  pPage->max1bytePayload = pBt->max1bytePayload;
   return SQLITE_OK;
 }
 
@@ -37191,7 +49303,7 @@ static int decodeFlags(MemPage *pPage, int flagByte){
 ** guarantee that the page is well-formed.  It only shows that
 ** we failed to detect any corruption.
 */
-SQLITE_PRIVATE int sqlite3BtreeInitPage(MemPage *pPage){
+static int btreeInitPage(MemPage *pPage){
 
   assert( pPage->pBt!=0 );
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
@@ -37204,72 +49316,96 @@ SQLITE_PRIVATE int sqlite3BtreeInitPage(MemPage *pPage){
     u8 hdr;            /* Offset to beginning of page header */
     u8 *data;          /* Equal to pPage->aData */
     BtShared *pBt;        /* The main btree structure */
-    u16 usableSize;    /* Amount of usable space on each page */
+    int usableSize;    /* Amount of usable space on each page */
     u16 cellOffset;    /* Offset from start of page to first cell pointer */
-    u16 nFree;         /* Number of unused bytes on the page */
-    u16 top;           /* First byte of the cell content area */
+    int nFree;         /* Number of unused bytes on the page */
+    int top;           /* First byte of the cell content area */
+    int iCellFirst;    /* First allowable cell or freeblock offset */
+    int iCellLast;     /* Last possible cell or freeblock offset */
 
     pBt = pPage->pBt;
 
     hdr = pPage->hdrOffset;
     data = pPage->aData;
     if( decodeFlags(pPage, data[hdr]) ) return SQLITE_CORRUPT_BKPT;
-    assert( pBt->pageSize>=512 && pBt->pageSize<=32768 );
-    pPage->maskPage = pBt->pageSize - 1;
+    assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
+    pPage->maskPage = (u16)(pBt->pageSize - 1);
     pPage->nOverflow = 0;
     usableSize = pBt->usableSize;
     pPage->cellOffset = cellOffset = hdr + 12 - 4*pPage->leaf;
-    top = get2byte(&data[hdr+5]);
+    pPage->aDataEnd = &data[usableSize];
+    pPage->aCellIdx = &data[cellOffset];
+    top = get2byteNotZero(&data[hdr+5]);
     pPage->nCell = get2byte(&data[hdr+3]);
     if( pPage->nCell>MX_CELL(pBt) ){
       /* To many cells for a single page.  The page must be corrupt */
       return SQLITE_CORRUPT_BKPT;
     }
-  
+    testcase( pPage->nCell==MX_CELL(pBt) );
+
+    /* A malformed database page might cause us to read past the end
+    ** of page when parsing a cell.  
+    **
+    ** The following block of code checks early to see if a cell extends
+    ** past the end of a page boundary and causes SQLITE_CORRUPT to be 
+    ** returned if it does.
+    */
+    iCellFirst = cellOffset + 2*pPage->nCell;
+    iCellLast = usableSize - 4;
+#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
+    {
+      int i;            /* Index into the cell pointer array */
+      int sz;           /* Size of a cell */
+
+      if( !pPage->leaf ) iCellLast--;
+      for(i=0; i<pPage->nCell; i++){
+        pc = get2byte(&data[cellOffset+i*2]);
+        testcase( pc==iCellFirst );
+        testcase( pc==iCellLast );
+        if( pc<iCellFirst || pc>iCellLast ){
+          return SQLITE_CORRUPT_BKPT;
+        }
+        sz = cellSizePtr(pPage, &data[pc]);
+        testcase( pc+sz==usableSize );
+        if( pc+sz>usableSize ){
+          return SQLITE_CORRUPT_BKPT;
+        }
+      }
+      if( !pPage->leaf ) iCellLast++;
+    }  
+#endif
+
     /* Compute the total free space on the page */
     pc = get2byte(&data[hdr+1]);
-    nFree = data[hdr+7] + top - (cellOffset + 2*pPage->nCell);
+    nFree = data[hdr+7] + top;
     while( pc>0 ){
       u16 next, size;
-      if( pc>usableSize-4 ){
-        /* Free block is off the page */
+      if( pc<iCellFirst || pc>iCellLast ){
+        /* Start of free block is off the page */
         return SQLITE_CORRUPT_BKPT; 
       }
       next = get2byte(&data[pc]);
       size = get2byte(&data[pc+2]);
-      if( next>0 && next<=pc+size+3 ){
-        /* Free blocks must be in accending order */
+      if( (next>0 && next<=pc+size+3) || pc+size>usableSize ){
+        /* Free blocks must be in ascending order. And the last byte of
+        ** the free-block must lie on the database page.  */
         return SQLITE_CORRUPT_BKPT; 
       }
-      nFree += size;
+      nFree = nFree + size;
       pc = next;
     }
-    pPage->nFree = (u16)nFree;
-    if( nFree>=usableSize ){
-      /* Free space cannot exceed total page size */
+
+    /* At this point, nFree contains the sum of the offset to the start
+    ** of the cell-content area plus the number of free bytes within
+    ** the cell-content area. If this is greater than the usable-size
+    ** of the page, then the page must be corrupted. This check also
+    ** serves to verify that the offset to the start of the cell-content
+    ** area, according to the page header, lies within the page.
+    */
+    if( nFree>usableSize ){
       return SQLITE_CORRUPT_BKPT; 
     }
-
-#if 0
-  /* Check that all the offsets in the cell offset array are within range. 
-  ** 
-  ** Omitting this consistency check and using the pPage->maskPage mask
-  ** to prevent overrunning the page buffer in findCell() results in a
-  ** 2.5% performance gain.
-  */
-  {
-    u8 *pOff;        /* Iterator used to check all cell offsets are in range */
-    u8 *pEnd;        /* Pointer to end of cell offset array */
-    u8 mask;         /* Mask of bits that must be zero in MSB of cell offsets */
-    mask = ~(((u8)(pBt->pageSize>>8))-1);
-    pEnd = &data[cellOffset + pPage->nCell*2];
-    for(pOff=&data[cellOffset]; pOff!=pEnd && !((*pOff)&mask); pOff+=2);
-    if( pOff!=pEnd ){
-      return SQLITE_CORRUPT_BKPT;
-    }
-  }
-#endif
-
+    pPage->nFree = (u16)(nFree - iCellFirst);
     pPage->isInit = 1;
   }
   return SQLITE_OK;
@@ -37290,19 +49426,23 @@ static void zeroPage(MemPage *pPage, int flags){
   assert( sqlite3PagerGetData(pPage->pDbPage) == data );
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
   assert( sqlite3_mutex_held(pBt->mutex) );
-  /*memset(&data[hdr], 0, pBt->usableSize - hdr);*/
+  if( pBt->btsFlags & BTS_SECURE_DELETE ){
+    memset(&data[hdr], 0, pBt->usableSize - hdr);
+  }
   data[hdr] = (char)flags;
   first = hdr + 8 + 4*((flags&PTF_LEAF)==0 ?1:0);
   memset(&data[hdr+1], 0, 4);
   data[hdr+7] = 0;
   put2byte(&data[hdr+5], pBt->usableSize);
-  pPage->nFree = pBt->usableSize - first;
+  pPage->nFree = (u16)(pBt->usableSize - first);
   decodeFlags(pPage, flags);
   pPage->hdrOffset = hdr;
   pPage->cellOffset = first;
+  pPage->aDataEnd = &data[pBt->usableSize];
+  pPage->aCellIdx = &data[first];
   pPage->nOverflow = 0;
-  assert( pBt->pageSize>=512 && pBt->pageSize<=32768 );
-  pPage->maskPage = pBt->pageSize - 1;
+  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
+  pPage->maskPage = (u16)(pBt->pageSize - 1);
   pPage->nCell = 0;
   pPage->isInit = 1;
 }
@@ -37333,7 +49473,7 @@ static MemPage *btreePageFromDbPage(DbPage *pDbPage, Pgno pgno, BtShared *pBt){
 ** means we have started to be concerned about content and the disk
 ** read should occur at that point.
 */
-SQLITE_PRIVATE int sqlite3BtreeGetPage(
+static int btreeGetPage(
   BtShared *pBt,       /* The btree */
   Pgno pgno,           /* Number of the page to fetch */
   MemPage **ppPage,    /* Return the page in this parameter */
@@ -37350,22 +49490,40 @@ SQLITE_PRIVATE int sqlite3BtreeGetPage(
 }
 
 /*
-** Return the size of the database file in pages. If there is any kind of
-** error, return ((unsigned int)-1).
+** Retrieve a page from the pager cache. If the requested page is not
+** already in the pager cache return NULL. Initialize the MemPage.pBt and
+** MemPage.aData elements if needed.
 */
-static Pgno pagerPagecount(BtShared *pBt){
-  int nPage = -1;
-  int rc;
-  assert( pBt->pPage1 );
-  rc = sqlite3PagerPagecount(pBt->pPager, &nPage);
-  assert( rc==SQLITE_OK || nPage==-1 );
-  return (Pgno)nPage;
+static MemPage *btreePageLookup(BtShared *pBt, Pgno pgno){
+  DbPage *pDbPage;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  pDbPage = sqlite3PagerLookup(pBt->pPager, pgno);
+  if( pDbPage ){
+    return btreePageFromDbPage(pDbPage, pgno, pBt);
+  }
+  return 0;
 }
 
 /*
-** Get a page from the pager and initialize it.  This routine
-** is just a convenience wrapper around separate calls to
-** sqlite3BtreeGetPage() and sqlite3BtreeInitPage().
+** Return the size of the database file in pages. If there is any kind of
+** error, return ((unsigned int)-1).
+*/
+static Pgno btreePagecount(BtShared *pBt){
+  return pBt->nPage;
+}
+SQLITE_PRIVATE u32 sqlite3BtreeLastPage(Btree *p){
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( ((p->pBt->nPage)&0x8000000)==0 );
+  return (int)btreePagecount(p->pBt);
+}
+
+/*
+** Get a page from the pager and initialize it.  This routine is just a
+** convenience wrapper around separate calls to btreeGetPage() and 
+** btreeInitPage().
+**
+** If an error occurs, then the value *ppPage is set to is undefined. It
+** may remain unchanged, or it may be set to an invalid value.
 */
 static int getAndInitPage(
   BtShared *pBt,          /* The database file */
@@ -37373,50 +49531,31 @@ static int getAndInitPage(
   MemPage **ppPage     /* Write the page pointer here */
 ){
   int rc;
-  DbPage *pDbPage;
-  MemPage *pPage;
-
   assert( sqlite3_mutex_held(pBt->mutex) );
-  if( pgno==0 ){
-    return SQLITE_CORRUPT_BKPT; 
+
+  if( pgno>btreePagecount(pBt) ){
+    rc = SQLITE_CORRUPT_BKPT;
+  }else{
+    rc = btreeGetPage(pBt, pgno, ppPage, 0);
+    if( rc==SQLITE_OK ){
+      rc = btreeInitPage(*ppPage);
+      if( rc!=SQLITE_OK ){
+        releasePage(*ppPage);
+      }
+    }
   }
 
-  /* It is often the case that the page we want is already in cache.
-  ** If so, get it directly.  This saves us from having to call
-  ** pagerPagecount() to make sure pgno is within limits, which results
-  ** in a measureable performance improvements.
-  */
-  pDbPage = sqlite3PagerLookup(pBt->pPager, pgno);
-  if( pDbPage ){
-    /* Page is already in cache */
-    *ppPage = pPage = btreePageFromDbPage(pDbPage, pgno, pBt);
-    rc = SQLITE_OK;
-  }else{
-    /* Page not in cache.  Acquire it. */
-    if( pgno>pagerPagecount(pBt) ){
-      return SQLITE_CORRUPT_BKPT; 
-    }
-    rc = sqlite3BtreeGetPage(pBt, pgno, ppPage, 0);
-    if( rc ) return rc;
-    pPage = *ppPage;
-  }
-  if( !pPage->isInit ){
-    rc = sqlite3BtreeInitPage(pPage);
-  }
-  if( rc!=SQLITE_OK ){
-    releasePage(pPage);
-    *ppPage = 0;
-  }
+  testcase( pgno==0 );
+  assert( pgno!=0 || rc==SQLITE_CORRUPT );
   return rc;
 }
 
 /*
 ** Release a MemPage.  This should be called once for each prior
-** call to sqlite3BtreeGetPage.
+** call to btreeGetPage.
 */
 static void releasePage(MemPage *pPage){
   if( pPage ){
-    assert( pPage->nOverflow==0 || sqlite3PagerPageRefcount(pPage->pDbPage)>1 );
     assert( pPage->aData );
     assert( pPage->pBt );
     assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
@@ -37437,11 +49576,18 @@ static void releasePage(MemPage *pPage){
 static void pageReinit(DbPage *pData){
   MemPage *pPage;
   pPage = (MemPage *)sqlite3PagerGetExtra(pData);
+  assert( sqlite3PagerPageRefcount(pData)>0 );
   if( pPage->isInit ){
     assert( sqlite3_mutex_held(pPage->pBt->mutex) );
     pPage->isInit = 0;
-    if( sqlite3PagerPageRefcount(pData)>0 ){
-      sqlite3BtreeInitPage(pPage);
+    if( sqlite3PagerPageRefcount(pData)>1 ){
+      /* pPage might not be a btree page;  it might be an overflow page
+      ** or ptrmap page or a free page.  In those cases, the following
+      ** call to btreeInitPage() will likely return SQLITE_CORRUPT.
+      ** But no harm is done by this.  And it is very important that
+      ** btreeInitPage() be called on every btree page so we make
+      ** the call for every page that comes in for re-initing. */
+      btreeInitPage(pPage);
     }
   }
 }
@@ -37460,75 +49606,127 @@ static int btreeInvokeBusyHandler(void *pArg){
 ** Open a database file.
 ** 
 ** zFilename is the name of the database file.  If zFilename is NULL
-** a new database with a random name is created.  This randomly named
-** database file will be deleted when sqlite3BtreeClose() is called.
+** then an ephemeral database is created.  The ephemeral database might
+** be exclusively in memory, or it might use a disk-based memory cache.
+** Either way, the ephemeral database will be automatically deleted 
+** when sqlite3BtreeClose() is called.
+**
 ** If zFilename is ":memory:" then an in-memory database is created
 ** that is automatically destroyed when it is closed.
+**
+** The "flags" parameter is a bitmask that might contain bits like
+** BTREE_OMIT_JOURNAL and/or BTREE_MEMORY.
+**
+** If the database is already opened in the same database connection
+** and we are in shared cache mode, then the open will fail with an
+** SQLITE_CONSTRAINT error.  We cannot allow two or more BtShared
+** objects in the same database connection since doing so will lead
+** to problems with locking.
 */
 SQLITE_PRIVATE int sqlite3BtreeOpen(
+  sqlite3_vfs *pVfs,      /* VFS to use for this b-tree */
   const char *zFilename,  /* Name of the file containing the BTree database */
   sqlite3 *db,            /* Associated database handle */
   Btree **ppBtree,        /* Pointer to new Btree object written here */
   int flags,              /* Options */
   int vfsFlags            /* Flags passed through to sqlite3_vfs.xOpen() */
 ){
-  sqlite3_vfs *pVfs;      /* The VFS to use for this btree */
-  BtShared *pBt = 0;      /* Shared part of btree structure */
-  Btree *p;               /* Handle to return */
-  int rc = SQLITE_OK;
-  u8 nReserve;
-  unsigned char zDbHeader[100];
+  BtShared *pBt = 0;             /* Shared part of btree structure */
+  Btree *p;                      /* Handle to return */
+  sqlite3_mutex *mutexOpen = 0;  /* Prevents a race condition. Ticket #3537 */
+  int rc = SQLITE_OK;            /* Result code from this function */
+  u8 nReserve;                   /* Byte of unused space on each page */
+  unsigned char zDbHeader[100];  /* Database header content */
+
+  /* True if opening an ephemeral, temporary database */
+  const int isTempDb = zFilename==0 || zFilename[0]==0;
 
   /* Set the variable isMemdb to true for an in-memory database, or 
-  ** false for a file-based database. This symbol is only required if
-  ** either of the shared-data or autovacuum features are compiled 
-  ** into the library.
+  ** false for a file-based database.
   */
-#if !defined(SQLITE_OMIT_SHARED_CACHE) || !defined(SQLITE_OMIT_AUTOVACUUM)
-  #ifdef SQLITE_OMIT_MEMORYDB
-    const int isMemdb = 0;
-  #else
-    const int isMemdb = zFilename && !strcmp(zFilename, ":memory:");
-  #endif
+#ifdef SQLITE_OMIT_MEMORYDB
+  const int isMemdb = 0;
+#else
+  const int isMemdb = (zFilename && strcmp(zFilename, ":memory:")==0)
+                       || (isTempDb && sqlite3TempInMemory(db))
+                       || (vfsFlags & SQLITE_OPEN_MEMORY)!=0;
 #endif
 
   assert( db!=0 );
+  assert( pVfs!=0 );
   assert( sqlite3_mutex_held(db->mutex) );
+  assert( (flags&0xff)==flags );   /* flags fit in 8 bits */
 
-  pVfs = db->pVfs;
+  /* Only a BTREE_SINGLE database can be BTREE_UNORDERED */
+  assert( (flags & BTREE_UNORDERED)==0 || (flags & BTREE_SINGLE)!=0 );
+
+  /* A BTREE_SINGLE database is always a temporary and/or ephemeral */
+  assert( (flags & BTREE_SINGLE)==0 || isTempDb );
+
+  if( isMemdb ){
+    flags |= BTREE_MEMORY;
+  }
+  if( (vfsFlags & SQLITE_OPEN_MAIN_DB)!=0 && (isMemdb || isTempDb) ){
+    vfsFlags = (vfsFlags & ~SQLITE_OPEN_MAIN_DB) | SQLITE_OPEN_TEMP_DB;
+  }
   p = sqlite3MallocZero(sizeof(Btree));
   if( !p ){
     return SQLITE_NOMEM;
   }
   p->inTrans = TRANS_NONE;
   p->db = db;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  p->lock.pBtree = p;
+  p->lock.iTable = 1;
+#endif
 
 #if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
   /*
   ** If this Btree is a candidate for shared cache, try to find an
   ** existing BtShared object that we can share with
   */
-  if( isMemdb==0
-   && (db->flags & SQLITE_Vtab)==0
-   && zFilename && zFilename[0]
-  ){
-    if( sqlite3GlobalConfig.sharedCacheEnabled ){
+  if( isTempDb==0 && (isMemdb==0 || (vfsFlags&SQLITE_OPEN_URI)!=0) ){
+    if( vfsFlags & SQLITE_OPEN_SHAREDCACHE ){
       int nFullPathname = pVfs->mxPathname+1;
       char *zFullPathname = sqlite3Malloc(nFullPathname);
-      sqlite3_mutex *mutexShared;
+      MUTEX_LOGIC( sqlite3_mutex *mutexShared; )
       p->sharable = 1;
-      db->flags |= SQLITE_SharedCache;
       if( !zFullPathname ){
         sqlite3_free(p);
         return SQLITE_NOMEM;
       }
-      sqlite3OsFullPathname(pVfs, zFilename, nFullPathname, zFullPathname);
+      if( isMemdb ){
+        memcpy(zFullPathname, zFilename, sqlite3Strlen30(zFilename)+1);
+      }else{
+        rc = sqlite3OsFullPathname(pVfs, zFilename,
+                                   nFullPathname, zFullPathname);
+        if( rc ){
+          sqlite3_free(zFullPathname);
+          sqlite3_free(p);
+          return rc;
+        }
+      }
+#if SQLITE_THREADSAFE
+      mutexOpen = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_OPEN);
+      sqlite3_mutex_enter(mutexOpen);
       mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
       sqlite3_mutex_enter(mutexShared);
+#endif
       for(pBt=GLOBAL(BtShared*,sqlite3SharedCacheList); pBt; pBt=pBt->pNext){
         assert( pBt->nRef>0 );
-        if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt->pPager))
+        if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt->pPager, 0))
                  && sqlite3PagerVfs(pBt->pPager)==pVfs ){
+          int iDb;
+          for(iDb=db->nDb-1; iDb>=0; iDb--){
+            Btree *pExisting = db->aDb[iDb].pBt;
+            if( pExisting && pExisting->pBt==pBt ){
+              sqlite3_mutex_leave(mutexShared);
+              sqlite3_mutex_leave(mutexOpen);
+              sqlite3_free(zFullPathname);
+              sqlite3_free(p);
+              return SQLITE_CONSTRAINT;
+            }
+          }
           p->pBt = pBt;
           pBt->nRef++;
           break;
@@ -37567,25 +49765,28 @@ SQLITE_PRIVATE int sqlite3BtreeOpen(
       goto btree_open_out;
     }
     rc = sqlite3PagerOpen(pVfs, &pBt->pPager, zFilename,
-                          EXTRA_SIZE, flags, vfsFlags);
+                          EXTRA_SIZE, flags, vfsFlags, pageReinit);
     if( rc==SQLITE_OK ){
       rc = sqlite3PagerReadFileheader(pBt->pPager,sizeof(zDbHeader),zDbHeader);
     }
     if( rc!=SQLITE_OK ){
       goto btree_open_out;
     }
+    pBt->openFlags = (u8)flags;
+    pBt->db = db;
     sqlite3PagerSetBusyhandler(pBt->pPager, btreeInvokeBusyHandler, pBt);
     p->pBt = pBt;
   
-    sqlite3PagerSetReiniter(pBt->pPager, pageReinit);
     pBt->pCursor = 0;
     pBt->pPage1 = 0;
-    pBt->readOnly = sqlite3PagerIsreadonly(pBt->pPager);
-    pBt->pageSize = get2byte(&zDbHeader[16]);
+    if( sqlite3PagerIsreadonly(pBt->pPager) ) pBt->btsFlags |= BTS_READ_ONLY;
+#ifdef SQLITE_SECURE_DELETE
+    pBt->btsFlags |= BTS_SECURE_DELETE;
+#endif
+    pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
     if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
          || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
       pBt->pageSize = 0;
-      sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
 #ifndef SQLITE_OMIT_AUTOVACUUM
       /* If the magic name ":memory:" will create an in-memory database, then
       ** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
@@ -37601,23 +49802,24 @@ SQLITE_PRIVATE int sqlite3BtreeOpen(
       nReserve = 0;
     }else{
       nReserve = zDbHeader[20];
-      pBt->pageSizeFixed = 1;
+      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
 #ifndef SQLITE_OMIT_AUTOVACUUM
       pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
       pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
 #endif
     }
+    rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
+    if( rc ) goto btree_open_out;
     pBt->usableSize = pBt->pageSize - nReserve;
     assert( (pBt->pageSize & 7)==0 );  /* 8-byte alignment of pageSize */
-    sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
    
 #if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
     /* Add the new BtShared object to the linked list sharable BtShareds.
     */
     if( p->sharable ){
-      sqlite3_mutex *mutexShared;
+      MUTEX_LOGIC( sqlite3_mutex *mutexShared; )
       pBt->nRef = 1;
-      mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
+      MUTEX_LOGIC( mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);)
       if( SQLITE_THREADSAFE && sqlite3GlobalConfig.bCoreMutex ){
         pBt->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_FAST);
         if( pBt->mutex==0 ){
@@ -37675,6 +49877,18 @@ btree_open_out:
     sqlite3_free(pBt);
     sqlite3_free(p);
     *ppBtree = 0;
+  }else{
+    /* If the B-Tree was successfully opened, set the pager-cache size to the
+    ** default value. Except, when opening on an existing shared pager-cache,
+    ** do not change the pager-cache size.
+    */
+    if( sqlite3BtreeSchema(p, 0, 0)==0 ){
+      sqlite3PagerSetCachesize(p->pBt->pPager, SQLITE_DEFAULT_CACHE_SIZE);
+    }
+  }
+  if( mutexOpen ){
+    assert( sqlite3_mutex_held(mutexOpen) );
+    sqlite3_mutex_leave(mutexOpen);
   }
   return rc;
 }
@@ -37687,12 +49901,12 @@ btree_open_out:
 */
 static int removeFromSharingList(BtShared *pBt){
 #ifndef SQLITE_OMIT_SHARED_CACHE
-  sqlite3_mutex *pMaster;
+  MUTEX_LOGIC( sqlite3_mutex *pMaster; )
   BtShared *pList;
   int removed = 0;
 
   assert( sqlite3_mutex_notheld(pBt->mutex) );
-  pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
+  MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
   sqlite3_mutex_enter(pMaster);
   pBt->nRef--;
   if( pBt->nRef<=0 ){
@@ -37747,7 +49961,6 @@ SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
   /* Close all cursors opened via this handle.  */
   assert( sqlite3_mutex_held(p->db->mutex) );
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
   pCur = pBt->pCursor;
   while( pCur ){
     BtCursor *pTmp = pCur;
@@ -37761,7 +49974,7 @@ SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
   ** The call to sqlite3BtreeRollback() drops any table-locks held by
   ** this handle.
   */
-  sqlite3BtreeRollback(p);
+  sqlite3BtreeRollback(p, SQLITE_OK);
   sqlite3BtreeLeave(p);
 
   /* If there are still other outstanding references to the shared-btree
@@ -37780,7 +49993,7 @@ SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
     if( pBt->xFreeSchema && pBt->pSchema ){
       pBt->xFreeSchema(pBt->pSchema);
     }
-    sqlite3_free(pBt->pSchema);
+    sqlite3DbFree(0, pBt->pSchema);
     freeTempSpace(pBt);
     sqlite3_free(pBt);
   }
@@ -37829,11 +50042,17 @@ SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree *p, int mxPage){
 ** probability of damage to near zero but with a write performance reduction.
 */
 #ifndef SQLITE_OMIT_PAGER_PRAGMAS
-SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(Btree *p, int level, int fullSync){
+SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(
+  Btree *p,              /* The btree to set the safety level on */
+  int level,             /* PRAGMA synchronous.  1=OFF, 2=NORMAL, 3=FULL */
+  int fullSync,          /* PRAGMA fullfsync. */
+  int ckptFullSync       /* PRAGMA checkpoint_fullfync */
+){
   BtShared *pBt = p->pBt;
   assert( sqlite3_mutex_held(p->db->mutex) );
+  assert( level>=1 && level<=3 );
   sqlite3BtreeEnter(p);
-  sqlite3PagerSetSafetyLevel(pBt->pPager, level, fullSync);
+  sqlite3PagerSetSafetyLevel(pBt->pPager, level, fullSync, ckptFullSync);
   sqlite3BtreeLeave(p);
   return SQLITE_OK;
 }
@@ -37854,9 +50073,10 @@ SQLITE_PRIVATE int sqlite3BtreeSyncDisabled(Btree *p){
   return rc;
 }
 
-#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM)
 /*
 ** Change the default pages size and the number of reserved bytes per page.
+** Or, if the page size has already been fixed, return SQLITE_READONLY 
+** without changing anything.
 **
 ** The page size must be a power of 2 between 512 and 65536.  If the page
 ** size supplied does not meet this constraint then the page size is not
@@ -37869,13 +50089,16 @@ SQLITE_PRIVATE int sqlite3BtreeSyncDisabled(Btree *p){
 **
 ** If parameter nReserve is less than zero, then the number of reserved
 ** bytes per page is left unchanged.
+**
+** If the iFix!=0 then the BTS_PAGESIZE_FIXED flag is set so that the page size
+** and autovacuum mode can no longer be changed.
 */
-SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve){
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
   int rc = SQLITE_OK;
   BtShared *pBt = p->pBt;
   assert( nReserve>=-1 && nReserve<=255 );
   sqlite3BtreeEnter(p);
-  if( pBt->pageSizeFixed ){
+  if( pBt->btsFlags & BTS_PAGESIZE_FIXED ){
     sqlite3BtreeLeave(p);
     return SQLITE_READONLY;
   }
@@ -37887,11 +50110,12 @@ SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve)
         ((pageSize-1)&pageSize)==0 ){
     assert( (pageSize & 7)==0 );
     assert( !pBt->pPage1 && !pBt->pCursor );
-    pBt->pageSize = (u16)pageSize;
+    pBt->pageSize = (u32)pageSize;
     freeTempSpace(pBt);
-    rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
   }
+  rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
   pBt->usableSize = pBt->pageSize - (u16)nReserve;
+  if( iFix ) pBt->btsFlags |= BTS_PAGESIZE_FIXED;
   sqlite3BtreeLeave(p);
   return rc;
 }
@@ -37902,6 +50126,13 @@ SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve)
 SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree *p){
   return p->pBt->pageSize;
 }
+
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM)
+/*
+** Return the number of bytes of space at the end of every page that
+** are intentually left unused.  This is the "reserved" space that is
+** sometimes used by extensions.
+*/
 SQLITE_PRIVATE int sqlite3BtreeGetReserve(Btree *p){
   int n;
   sqlite3BtreeEnter(p);
@@ -37922,6 +50153,24 @@ SQLITE_PRIVATE int sqlite3BtreeMaxPageCount(Btree *p, int mxPage){
   sqlite3BtreeLeave(p);
   return n;
 }
+
+/*
+** Set the BTS_SECURE_DELETE flag if newFlag is 0 or 1.  If newFlag is -1,
+** then make no changes.  Always return the value of the BTS_SECURE_DELETE
+** setting after the change.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
+  int b;
+  if( p==0 ) return 0;
+  sqlite3BtreeEnter(p);
+  if( newFlag>=0 ){
+    p->pBt->btsFlags &= ~BTS_SECURE_DELETE;
+    if( newFlag ) p->pBt->btsFlags |= BTS_SECURE_DELETE;
+  } 
+  b = (p->pBt->btsFlags & BTS_SECURE_DELETE)!=0;
+  sqlite3BtreeLeave(p);
+  return b;
+}
 #endif /* !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM) */
 
 /*
@@ -37936,13 +50185,14 @@ SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *p, int autoVacuum){
 #else
   BtShared *pBt = p->pBt;
   int rc = SQLITE_OK;
-  u8 av = autoVacuum ?1:0;
+  u8 av = (u8)autoVacuum;
 
   sqlite3BtreeEnter(p);
-  if( pBt->pageSizeFixed && av!=pBt->autoVacuum ){
+  if( (pBt->btsFlags & BTS_PAGESIZE_FIXED)!=0 && (av ?1:0)!=pBt->autoVacuum ){
     rc = SQLITE_READONLY;
   }else{
-    pBt->autoVacuum = av;
+    pBt->autoVacuum = av ?1:0;
+    pBt->incrVacuum = av==2 ?1:0;
   }
   sqlite3BtreeLeave(p);
   return rc;
@@ -37980,35 +50230,71 @@ SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *p){
 ** is returned if we run out of memory. 
 */
 static int lockBtree(BtShared *pBt){
-  int rc;
-  MemPage *pPage1;
-  int nPage;
+  int rc;              /* Result code from subfunctions */
+  MemPage *pPage1;     /* Page 1 of the database file */
+  int nPage;           /* Number of pages in the database */
+  int nPageFile = 0;   /* Number of pages in the database file */
+  int nPageHeader;     /* Number of pages in the database according to hdr */
 
   assert( sqlite3_mutex_held(pBt->mutex) );
-  if( pBt->pPage1 ) return SQLITE_OK;
-  rc = sqlite3BtreeGetPage(pBt, 1, &pPage1, 0);
+  assert( pBt->pPage1==0 );
+  rc = sqlite3PagerSharedLock(pBt->pPager);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = btreeGetPage(pBt, 1, &pPage1, 0);
   if( rc!=SQLITE_OK ) return rc;
 
   /* Do some checking to help insure the file we opened really is
   ** a valid database file. 
   */
-  rc = sqlite3PagerPagecount(pBt->pPager, &nPage);
-  if( rc!=SQLITE_OK ){
-    goto page1_init_failed;
-  }else if( nPage>0 ){
-    int pageSize;
-    int usableSize;
+  nPage = nPageHeader = get4byte(28+(u8*)pPage1->aData);
+  sqlite3PagerPagecount(pBt->pPager, &nPageFile);
+  if( nPage==0 || memcmp(24+(u8*)pPage1->aData, 92+(u8*)pPage1->aData,4)!=0 ){
+    nPage = nPageFile;
+  }
+  if( nPage>0 ){
+    u32 pageSize;
+    u32 usableSize;
     u8 *page1 = pPage1->aData;
     rc = SQLITE_NOTADB;
     if( memcmp(page1, zMagicHeader, 16)!=0 ){
       goto page1_init_failed;
     }
+
+#ifdef SQLITE_OMIT_WAL
     if( page1[18]>1 ){
-      pBt->readOnly = 1;
+      pBt->btsFlags |= BTS_READ_ONLY;
     }
     if( page1[19]>1 ){
       goto page1_init_failed;
     }
+#else
+    if( page1[18]>2 ){
+      pBt->btsFlags |= BTS_READ_ONLY;
+    }
+    if( page1[19]>2 ){
+      goto page1_init_failed;
+    }
+
+    /* If the write version is set to 2, this database should be accessed
+    ** in WAL mode. If the log is not already open, open it now. Then 
+    ** return SQLITE_OK and return without populating BtShared.pPage1.
+    ** The caller detects this and calls this function again. This is
+    ** required as the version of page 1 currently in the page1 buffer
+    ** may not be the latest version - there may be a newer one in the log
+    ** file.
+    */
+    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
+      int isOpen = 0;
+      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
+      if( rc!=SQLITE_OK ){
+        goto page1_init_failed;
+      }else if( isOpen==0 ){
+        releasePage(pPage1);
+        return SQLITE_OK;
+      }
+      rc = SQLITE_NOTADB;
+    }
+#endif
 
     /* The maximum embedded fraction must be exactly 25%.  And the minimum
     ** embedded fraction must be 12.5% for both leaf-data and non-leaf-data.
@@ -38018,15 +50304,16 @@ static int lockBtree(BtShared *pBt){
     if( memcmp(&page1[21], "\100\040\040",3)!=0 ){
       goto page1_init_failed;
     }
-    pageSize = get2byte(&page1[16]);
-    if( ((pageSize-1)&pageSize)!=0 || pageSize<512 ||
-        (SQLITE_MAX_PAGE_SIZE<32768 && pageSize>SQLITE_MAX_PAGE_SIZE)
+    pageSize = (page1[16]<<8) | (page1[17]<<16);
+    if( ((pageSize-1)&pageSize)!=0
+     || pageSize>SQLITE_MAX_PAGE_SIZE 
+     || pageSize<=256 
     ){
       goto page1_init_failed;
     }
     assert( (pageSize & 7)==0 );
     usableSize = pageSize - page1[20];
-    if( pageSize!=pBt->pageSize ){
+    if( (u32)pageSize!=pBt->pageSize ){
       /* After reading the first page of the database assuming a page size
       ** of BtShared.pageSize, we have discovered that the page-size is
       ** actually pageSize. Unlock the database, leave pBt->pPage1 at
@@ -38034,17 +50321,22 @@ static int lockBtree(BtShared *pBt){
       ** again with the correct page-size.
       */
       releasePage(pPage1);
-      pBt->usableSize = (u16)usableSize;
-      pBt->pageSize = (u16)pageSize;
+      pBt->usableSize = usableSize;
+      pBt->pageSize = pageSize;
       freeTempSpace(pBt);
-      sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize);
-      return SQLITE_OK;
+      rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize,
+                                   pageSize-usableSize);
+      return rc;
     }
-    if( usableSize<500 ){
+    if( (pBt->db->flags & SQLITE_RecoveryMode)==0 && nPage>nPageFile ){
+      rc = SQLITE_CORRUPT_BKPT;
       goto page1_init_failed;
     }
-    pBt->pageSize = (u16)pageSize;
-    pBt->usableSize = (u16)usableSize;
+    if( usableSize<480 ){
+      goto page1_init_failed;
+    }
+    pBt->pageSize = pageSize;
+    pBt->usableSize = usableSize;
 #ifndef SQLITE_OMIT_AUTOVACUUM
     pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
     pBt->incrVacuum = (get4byte(&page1[36 + 7*4])?1:0);
@@ -38060,16 +50352,22 @@ static int lockBtree(BtShared *pBt){
   **     9-byte nKey value
   **     4-byte nData value
   **     4-byte overflow page pointer
-  ** So a cell consists of a 2-byte poiner, a header which is as much as
+  ** So a cell consists of a 2-byte pointer, a header which is as much as
   ** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
   ** page pointer.
   */
-  pBt->maxLocal = (pBt->usableSize-12)*64/255 - 23;
-  pBt->minLocal = (pBt->usableSize-12)*32/255 - 23;
-  pBt->maxLeaf = pBt->usableSize - 35;
-  pBt->minLeaf = (pBt->usableSize-12)*32/255 - 23;
+  pBt->maxLocal = (u16)((pBt->usableSize-12)*64/255 - 23);
+  pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
+  pBt->maxLeaf = (u16)(pBt->usableSize - 35);
+  pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);
+  if( pBt->maxLocal>127 ){
+    pBt->max1bytePayload = 127;
+  }else{
+    pBt->max1bytePayload = (u8)pBt->maxLocal;
+  }
   assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
   pBt->pPage1 = pPage1;
+  pBt->nPage = nPage;
   return SQLITE_OK;
 
 page1_init_failed:
@@ -38078,73 +50376,39 @@ page1_init_failed:
   return rc;
 }
 
-/*
-** This routine works like lockBtree() except that it also invokes the
-** busy callback if there is lock contention.
-*/
-static int lockBtreeWithRetry(Btree *pRef){
-  int rc = SQLITE_OK;
-
-  assert( sqlite3BtreeHoldsMutex(pRef) );
-  if( pRef->inTrans==TRANS_NONE ){
-    u8 inTransaction = pRef->pBt->inTransaction;
-    btreeIntegrity(pRef);
-    rc = sqlite3BtreeBeginTrans(pRef, 0);
-    pRef->pBt->inTransaction = inTransaction;
-    pRef->inTrans = TRANS_NONE;
-    if( rc==SQLITE_OK ){
-      pRef->pBt->nTransaction--;
-    }
-    btreeIntegrity(pRef);
-  }
-  return rc;
-}
-       
-
 /*
 ** If there are no outstanding cursors and we are not in the middle
 ** of a transaction but there is a read lock on the database, then
 ** this routine unrefs the first page of the database file which 
 ** has the effect of releasing the read lock.
 **
-** If there are any outstanding cursors, this routine is a no-op.
-**
 ** If there is a transaction in progress, this routine is a no-op.
 */
 static void unlockBtreeIfUnused(BtShared *pBt){
   assert( sqlite3_mutex_held(pBt->mutex) );
-  if( pBt->inTransaction==TRANS_NONE && pBt->pCursor==0 && pBt->pPage1!=0 ){
-    if( sqlite3PagerRefcount(pBt->pPager)>=1 ){
-      assert( pBt->pPage1->aData );
-#if 0
-      if( pBt->pPage1->aData==0 ){
-        MemPage *pPage = pBt->pPage1;
-        pPage->aData = sqlite3PagerGetData(pPage->pDbPage);
-        pPage->pBt = pBt;
-        pPage->pgno = 1;
-      }
-#endif
-      releasePage(pBt->pPage1);
-    }
+  assert( pBt->pCursor==0 || pBt->inTransaction>TRANS_NONE );
+  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
+    assert( pBt->pPage1->aData );
+    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
+    assert( pBt->pPage1->aData );
+    releasePage(pBt->pPage1);
     pBt->pPage1 = 0;
-    pBt->inStmt = 0;
   }
 }
 
 /*
-** Create a new database by initializing the first page of the
-** file.
+** If pBt points to an empty file then convert that empty file
+** into a new empty database by initializing the first page of
+** the database.
 */
 static int newDatabase(BtShared *pBt){
   MemPage *pP1;
   unsigned char *data;
   int rc;
-  int nPage;
 
   assert( sqlite3_mutex_held(pBt->mutex) );
-  rc = sqlite3PagerPagecount(pBt->pPager, &nPage);
-  if( rc!=SQLITE_OK || nPage>0 ){
-    return rc;
+  if( pBt->nPage>0 ){
+    return SQLITE_OK;
   }
   pP1 = pBt->pPage1;
   assert( pP1!=0 );
@@ -38153,7 +50417,8 @@ static int newDatabase(BtShared *pBt){
   if( rc ) return rc;
   memcpy(data, zMagicHeader, sizeof(zMagicHeader));
   assert( sizeof(zMagicHeader)==16 );
-  put2byte(&data[16], pBt->pageSize);
+  data[16] = (u8)((pBt->pageSize>>8)&0xff);
+  data[17] = (u8)((pBt->pageSize>>16)&0xff);
   data[18] = 1;
   data[19] = 1;
   assert( pBt->usableSize<=pBt->pageSize && pBt->usableSize+255>=pBt->pageSize);
@@ -38163,13 +50428,15 @@ static int newDatabase(BtShared *pBt){
   data[23] = 32;
   memset(&data[24], 0, 100-24);
   zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
-  pBt->pageSizeFixed = 1;
+  pBt->btsFlags |= BTS_PAGESIZE_FIXED;
 #ifndef SQLITE_OMIT_AUTOVACUUM
   assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
   assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
   put4byte(&data[36 + 4*4], pBt->autoVacuum);
   put4byte(&data[36 + 7*4], pBt->incrVacuum);
 #endif
+  pBt->nPage = 1;
+  data[31] = 1;
   return SQLITE_OK;
 }
 
@@ -38209,11 +50476,11 @@ static int newDatabase(BtShared *pBt){
 ** proceed.
 */
 SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
+  sqlite3 *pBlock = 0;
   BtShared *pBt = p->pBt;
   int rc = SQLITE_OK;
 
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
   btreeIntegrity(p);
 
   /* If the btree is already in a write-transaction, or it
@@ -38225,72 +50492,109 @@ SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
   }
 
   /* Write transactions are not possible on a read-only database */
-  if( pBt->readOnly && wrflag ){
+  if( (pBt->btsFlags & BTS_READ_ONLY)!=0 && wrflag ){
     rc = SQLITE_READONLY;
     goto trans_begun;
   }
 
+#ifndef SQLITE_OMIT_SHARED_CACHE
   /* If another database handle has already opened a write transaction 
   ** on this shared-btree structure and a second write transaction is
-  ** requested, return SQLITE_BUSY.
+  ** requested, return SQLITE_LOCKED.
   */
-  if( pBt->inTransaction==TRANS_WRITE && wrflag ){
-    rc = SQLITE_BUSY;
-    goto trans_begun;
-  }
-
-#ifndef SQLITE_OMIT_SHARED_CACHE
-  if( wrflag>1 ){
+  if( (wrflag && pBt->inTransaction==TRANS_WRITE)
+   || (pBt->btsFlags & BTS_PENDING)!=0
+  ){
+    pBlock = pBt->pWriter->db;
+  }else if( wrflag>1 ){
     BtLock *pIter;
     for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
       if( pIter->pBtree!=p ){
-        rc = SQLITE_BUSY;
-        goto trans_begun;
+        pBlock = pIter->pBtree->db;
+        break;
       }
     }
   }
+  if( pBlock ){
+    sqlite3ConnectionBlocked(p->db, pBlock);
+    rc = SQLITE_LOCKED_SHAREDCACHE;
+    goto trans_begun;
+  }
 #endif
 
+  /* Any read-only or read-write transaction implies a read-lock on 
+  ** page 1. So if some other shared-cache client already has a write-lock 
+  ** on page 1, the transaction cannot be opened. */
+  rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
+  if( SQLITE_OK!=rc ) goto trans_begun;
+
+  pBt->btsFlags &= ~BTS_INITIALLY_EMPTY;
+  if( pBt->nPage==0 ) pBt->btsFlags |= BTS_INITIALLY_EMPTY;
   do {
-    if( pBt->pPage1==0 ){
-      do{
-        rc = lockBtree(pBt);
-      }while( pBt->pPage1==0 && rc==SQLITE_OK );
-    }
+    /* Call lockBtree() until either pBt->pPage1 is populated or
+    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
+    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
+    ** reading page 1 it discovers that the page-size of the database 
+    ** file is not pBt->pageSize. In this case lockBtree() will update
+    ** pBt->pageSize to the page-size of the file on disk.
+    */
+    while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
 
     if( rc==SQLITE_OK && wrflag ){
-      if( pBt->readOnly ){
+      if( (pBt->btsFlags & BTS_READ_ONLY)!=0 ){
         rc = SQLITE_READONLY;
       }else{
-        rc = sqlite3PagerBegin(pBt->pPage1->pDbPage, wrflag>1);
+        rc = sqlite3PagerBegin(pBt->pPager,wrflag>1,sqlite3TempInMemory(p->db));
         if( rc==SQLITE_OK ){
           rc = newDatabase(pBt);
         }
       }
     }
   
-    if( rc==SQLITE_OK ){
-      if( wrflag ) pBt->inStmt = 0;
-    }else{
+    if( rc!=SQLITE_OK ){
       unlockBtreeIfUnused(pBt);
     }
-  }while( rc==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
+  }while( (rc&0xFF)==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
           btreeInvokeBusyHandler(pBt) );
 
   if( rc==SQLITE_OK ){
     if( p->inTrans==TRANS_NONE ){
       pBt->nTransaction++;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+      if( p->sharable ){
+        assert( p->lock.pBtree==p && p->lock.iTable==1 );
+        p->lock.eLock = READ_LOCK;
+        p->lock.pNext = pBt->pLock;
+        pBt->pLock = &p->lock;
+      }
+#endif
     }
     p->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);
     if( p->inTrans>pBt->inTransaction ){
       pBt->inTransaction = p->inTrans;
     }
+    if( wrflag ){
+      MemPage *pPage1 = pBt->pPage1;
 #ifndef SQLITE_OMIT_SHARED_CACHE
-    if( wrflag>1 ){
-      assert( !pBt->pExclusive );
-      pBt->pExclusive = p;
-    }
+      assert( !pBt->pWriter );
+      pBt->pWriter = p;
+      pBt->btsFlags &= ~BTS_EXCLUSIVE;
+      if( wrflag>1 ) pBt->btsFlags |= BTS_EXCLUSIVE;
 #endif
+
+      /* If the db-size header field is incorrect (as it may be if an old
+      ** client has been writing the database file), update it now. Doing
+      ** this sooner rather than later means the database size can safely 
+      ** re-read the database size from page 1 if a savepoint or transaction
+      ** rollback occurs within the transaction.
+      */
+      if( pBt->nPage!=get4byte(&pPage1->aData[28]) ){
+        rc = sqlite3PagerWrite(pPage1->pDbPage);
+        if( rc==SQLITE_OK ){
+          put4byte(&pPage1->aData[28], pBt->nPage);
+        }
+      }
+    }
   }
 
 
@@ -38324,7 +50628,7 @@ static int setChildPtrmaps(MemPage *pPage){
   Pgno pgno = pPage->pgno;
 
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  rc = sqlite3BtreeInitPage(pPage);
+  rc = btreeInitPage(pPage);
   if( rc!=SQLITE_OK ){
     goto set_child_ptrmaps_out;
   }
@@ -38333,21 +50637,17 @@ static int setChildPtrmaps(MemPage *pPage){
   for(i=0; i<nCell; i++){
     u8 *pCell = findCell(pPage, i);
 
-    rc = ptrmapPutOvflPtr(pPage, pCell);
-    if( rc!=SQLITE_OK ){
-      goto set_child_ptrmaps_out;
-    }
+    ptrmapPutOvflPtr(pPage, pCell, &rc);
 
     if( !pPage->leaf ){
       Pgno childPgno = get4byte(pCell);
-      rc = ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno);
-      if( rc!=SQLITE_OK ) goto set_child_ptrmaps_out;
+      ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
     }
   }
 
   if( !pPage->leaf ){
     Pgno childPgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
-    rc = ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno);
+    ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
   }
 
 set_child_ptrmaps_out:
@@ -38356,10 +50656,9 @@ set_child_ptrmaps_out:
 }
 
 /*
-** Somewhere on pPage, which is guarenteed to be a btree page, not an overflow
-** page, is a pointer to page iFrom. Modify this pointer so that it points to
-** iTo. Parameter eType describes the type of pointer to be modified, as 
-** follows:
+** Somewhere on pPage is a pointer to page iFrom.  Modify this pointer so
+** that it points to iTo. Parameter eType describes the type of pointer to
+** be modified, as  follows:
 **
 ** PTRMAP_BTREE:     pPage is a btree-page. The pointer points at a child 
 **                   page of pPage.
@@ -38384,19 +50683,20 @@ static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
     int i;
     int nCell;
 
-    sqlite3BtreeInitPage(pPage);
+    btreeInitPage(pPage);
     nCell = pPage->nCell;
 
     for(i=0; i<nCell; i++){
       u8 *pCell = findCell(pPage, i);
       if( eType==PTRMAP_OVERFLOW1 ){
         CellInfo info;
-        sqlite3BtreeParseCellPtr(pPage, pCell, &info);
-        if( info.iOverflow ){
-          if( iFrom==get4byte(&pCell[info.iOverflow]) ){
-            put4byte(&pCell[info.iOverflow], iTo);
-            break;
-          }
+        btreeParseCellPtr(pPage, pCell, &info);
+        if( info.iOverflow
+         && pCell+info.iOverflow+3<=pPage->aData+pPage->maskPage
+         && iFrom==get4byte(&pCell[info.iOverflow])
+        ){
+          put4byte(&pCell[info.iOverflow], iTo);
+          break;
         }
       }else{
         if( get4byte(pCell)==iFrom ){
@@ -38423,6 +50723,11 @@ static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
 /*
 ** Move the open database page pDbPage to location iFreePage in the 
 ** database. The pDbPage reference remains valid.
+**
+** The isCommit flag indicates that there is no need to remember that
+** the journal needs to be sync()ed before database page pDbPage->pgno 
+** can be written to. The caller has already promised not to write to that
+** page.
 */
 static int relocatePage(
   BtShared *pBt,           /* Btree */
@@ -38430,7 +50735,7 @@ static int relocatePage(
   u8 eType,                /* Pointer map 'type' entry for pDbPage */
   Pgno iPtrPage,           /* Pointer map 'page-no' entry for pDbPage */
   Pgno iFreePage,          /* The location to move pDbPage to */
-  int isCommit
+  int isCommit             /* isCommit flag passed to sqlite3PagerMovepage */
 ){
   MemPage *pPtrPage;   /* The page that contains a pointer to pDbPage */
   Pgno iDbPage = pDbPage->pgno;
@@ -38467,7 +50772,7 @@ static int relocatePage(
   }else{
     Pgno nextOvfl = get4byte(pDbPage->aData);
     if( nextOvfl!=0 ){
-      rc = ptrmapPut(pBt, nextOvfl, PTRMAP_OVERFLOW2, iFreePage);
+      ptrmapPut(pBt, nextOvfl, PTRMAP_OVERFLOW2, iFreePage, &rc);
       if( rc!=SQLITE_OK ){
         return rc;
       }
@@ -38479,7 +50784,7 @@ static int relocatePage(
   ** iPtrPage.
   */
   if( eType!=PTRMAP_ROOTPAGE ){
-    rc = sqlite3BtreeGetPage(pBt, iPtrPage, &pPtrPage, 0);
+    rc = btreeGetPage(pBt, iPtrPage, &pPtrPage, 0);
     if( rc!=SQLITE_OK ){
       return rc;
     }
@@ -38491,7 +50796,7 @@ static int relocatePage(
     rc = modifyPagePointer(pPtrPage, iDbPage, iFreePage, eType);
     releasePage(pPtrPage);
     if( rc==SQLITE_OK ){
-      rc = ptrmapPut(pBt, iFreePage, eType, iPtrPage);
+      ptrmapPut(pBt, iFreePage, eType, iPtrPage, &rc);
     }
   }
   return rc;
@@ -38509,24 +50814,28 @@ static int allocateBtreePage(BtShared *, MemPage **, Pgno *, Pgno, u8);
 ** database so that the last page of the file currently in use
 ** is no longer in use.
 **
-** If the nFin parameter is non-zero, the implementation assumes
+** If the nFin parameter is non-zero, this function assumes
 ** that the caller will keep calling incrVacuumStep() until
 ** it returns SQLITE_DONE or an error, and that nFin is the
 ** number of pages the database file will contain after this 
-** process is complete.
+** process is complete.  If nFin is zero, it is assumed that
+** incrVacuumStep() will be called a finite amount of times
+** which may or may not empty the freelist.  A full autovacuum
+** has nFin>0.  A "PRAGMA incremental_vacuum" has nFin==0.
 */
 static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg){
   Pgno nFreeList;           /* Number of pages still on the free-list */
+  int rc;
 
   assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( iLastPg>nFin );
 
   if( !PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg!=PENDING_BYTE_PAGE(pBt) ){
-    int rc;
     u8 eType;
     Pgno iPtrPage;
 
     nFreeList = get4byte(&pBt->pPage1->aData[36]);
-    if( nFreeList==0 || nFin==iLastPg ){
+    if( nFreeList==0 ){
       return SQLITE_DONE;
     }
 
@@ -38558,7 +50867,7 @@ static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg){
       Pgno iFreePg;             /* Index of free page to move pLastPg to */
       MemPage *pLastPg;
 
-      rc = sqlite3BtreeGetPage(pBt, iLastPg, &pLastPg, 0);
+      rc = btreeGetPage(pBt, iLastPg, &pLastPg, 0);
       if( rc!=SQLITE_OK ){
         return rc;
       }
@@ -38595,9 +50904,22 @@ static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg){
   if( nFin==0 ){
     iLastPg--;
     while( iLastPg==PENDING_BYTE_PAGE(pBt)||PTRMAP_ISPAGE(pBt, iLastPg) ){
+      if( PTRMAP_ISPAGE(pBt, iLastPg) ){
+        MemPage *pPg;
+        rc = btreeGetPage(pBt, iLastPg, &pPg, 0);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        rc = sqlite3PagerWrite(pPg->pDbPage);
+        releasePage(pPg);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+      }
       iLastPg--;
     }
     sqlite3PagerTruncateImage(pBt->pPager, iLastPg);
+    pBt->nPage = iLastPg;
   }
   return SQLITE_OK;
 }
@@ -38607,7 +50929,7 @@ static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg){
 ** It performs a single unit of work towards an incremental vacuum.
 **
 ** If the incremental vacuum is finished after this function has run,
-** SQLITE_DONE is returned. If it is not finished, but no error occured,
+** SQLITE_DONE is returned. If it is not finished, but no error occurred,
 ** SQLITE_OK is returned. Otherwise an SQLite error code. 
 */
 SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *p){
@@ -38615,13 +50937,16 @@ SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *p){
   BtShared *pBt = p->pBt;
 
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
   assert( pBt->inTransaction==TRANS_WRITE && p->inTrans==TRANS_WRITE );
   if( !pBt->autoVacuum ){
     rc = SQLITE_DONE;
   }else{
     invalidateAllOverflowCache(pBt);
-    rc = incrVacuumStep(pBt, 0, sqlite3PagerImageSize(pBt->pPager));
+    rc = incrVacuumStep(pBt, 0, btreePagecount(pBt));
+    if( rc==SQLITE_OK ){
+      rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+      put4byte(&pBt->pPage1->aData[28], pBt->nPage);
+    }
   }
   sqlite3BtreeLeave(p);
   return rc;
@@ -38645,38 +50970,44 @@ static int autoVacuumCommit(BtShared *pBt){
   invalidateAllOverflowCache(pBt);
   assert(pBt->autoVacuum);
   if( !pBt->incrVacuum ){
-    Pgno nFin;
-    Pgno nFree;
-    Pgno nPtrmap;
-    Pgno iFree;
-    const int pgsz = pBt->pageSize;
-    Pgno nOrig = pagerPagecount(pBt);
+    Pgno nFin;         /* Number of pages in database after autovacuuming */
+    Pgno nFree;        /* Number of pages on the freelist initially */
+    Pgno nPtrmap;      /* Number of PtrMap pages to be freed */
+    Pgno iFree;        /* The next page to be freed */
+    int nEntry;        /* Number of entries on one ptrmap page */
+    Pgno nOrig;        /* Database size before freeing */
 
-    if( PTRMAP_ISPAGE(pBt, nOrig) ){
+    nOrig = btreePagecount(pBt);
+    if( PTRMAP_ISPAGE(pBt, nOrig) || nOrig==PENDING_BYTE_PAGE(pBt) ){
+      /* It is not possible to create a database for which the final page
+      ** is either a pointer-map page or the pending-byte page. If one
+      ** is encountered, this indicates corruption.
+      */
       return SQLITE_CORRUPT_BKPT;
     }
-    if( nOrig==PENDING_BYTE_PAGE(pBt) ){
-      nOrig--;
-    }
+
     nFree = get4byte(&pBt->pPage1->aData[36]);
-    nPtrmap = (nFree-nOrig+PTRMAP_PAGENO(pBt, nOrig)+pgsz/5)/(pgsz/5);
+    nEntry = pBt->usableSize/5;
+    nPtrmap = (nFree-nOrig+PTRMAP_PAGENO(pBt, nOrig)+nEntry)/nEntry;
     nFin = nOrig - nFree - nPtrmap;
-    if( nOrig>PENDING_BYTE_PAGE(pBt) && nFin<=PENDING_BYTE_PAGE(pBt) ){
+    if( nOrig>PENDING_BYTE_PAGE(pBt) && nFin<PENDING_BYTE_PAGE(pBt) ){
       nFin--;
     }
     while( PTRMAP_ISPAGE(pBt, nFin) || nFin==PENDING_BYTE_PAGE(pBt) ){
       nFin--;
     }
+    if( nFin>nOrig ) return SQLITE_CORRUPT_BKPT;
 
     for(iFree=nOrig; iFree>nFin && rc==SQLITE_OK; iFree--){
       rc = incrVacuumStep(pBt, nFin, iFree);
     }
     if( (rc==SQLITE_DONE || rc==SQLITE_OK) && nFree>0 ){
-      rc = SQLITE_OK;
       rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
       put4byte(&pBt->pPage1->aData[32], 0);
       put4byte(&pBt->pPage1->aData[36], 0);
+      put4byte(&pBt->pPage1->aData[28], nFin);
       sqlite3PagerTruncateImage(pBt->pPager, nFin);
+      pBt->nPage = nFin;
     }
     if( rc!=SQLITE_OK ){
       sqlite3PagerRollback(pPager);
@@ -38687,7 +51018,9 @@ static int autoVacuumCommit(BtShared *pBt){
   return rc;
 }
 
-#endif /* ifndef SQLITE_OMIT_AUTOVACUUM */
+#else /* ifndef SQLITE_OMIT_AUTOVACUUM */
+# define setChildPtrmaps(x) SQLITE_OK
+#endif
 
 /*
 ** This routine does the first phase of a two-phase commit.  This routine
@@ -38699,7 +51032,7 @@ static int autoVacuumCommit(BtShared *pBt){
 ** database are written into the database file and flushed to oxide.
 ** At the end of this call, the rollback journal still exists on the
 ** disk and we are still holding all locks, so the transaction has not
-** committed.  See sqlite3BtreeCommit() for the second phase of the
+** committed.  See sqlite3BtreeCommitPhaseTwo() for the second phase of the
 ** commit process.
 **
 ** This call is a no-op if no write-transaction is currently active on pBt.
@@ -38720,7 +51053,6 @@ SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree *p, const char *zMaster){
   if( p->inTrans==TRANS_WRITE ){
     BtShared *pBt = p->pBt;
     sqlite3BtreeEnter(p);
-    pBt->db = p->db;
 #ifndef SQLITE_OMIT_AUTOVACUUM
     if( pBt->autoVacuum ){
       rc = autoVacuumCommit(pBt);
@@ -38736,25 +51068,73 @@ SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree *p, const char *zMaster){
   return rc;
 }
 
+/*
+** This function is called from both BtreeCommitPhaseTwo() and BtreeRollback()
+** at the conclusion of a transaction.
+*/
+static void btreeEndTransaction(Btree *p){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3BtreeHoldsMutex(p) );
+
+  btreeClearHasContent(pBt);
+  if( p->inTrans>TRANS_NONE && p->db->activeVdbeCnt>1 ){
+    /* If there are other active statements that belong to this database
+    ** handle, downgrade to a read-only transaction. The other statements
+    ** may still be reading from the database.  */
+    downgradeAllSharedCacheTableLocks(p);
+    p->inTrans = TRANS_READ;
+  }else{
+    /* If the handle had any kind of transaction open, decrement the 
+    ** transaction count of the shared btree. If the transaction count 
+    ** reaches 0, set the shared state to TRANS_NONE. The unlockBtreeIfUnused()
+    ** call below will unlock the pager.  */
+    if( p->inTrans!=TRANS_NONE ){
+      clearAllSharedCacheTableLocks(p);
+      pBt->nTransaction--;
+      if( 0==pBt->nTransaction ){
+        pBt->inTransaction = TRANS_NONE;
+      }
+    }
+
+    /* Set the current transaction state to TRANS_NONE and unlock the 
+    ** pager if this call closed the only read or write transaction.  */
+    p->inTrans = TRANS_NONE;
+    unlockBtreeIfUnused(pBt);
+  }
+
+  btreeIntegrity(p);
+}
+
 /*
 ** Commit the transaction currently in progress.
 **
 ** This routine implements the second phase of a 2-phase commit.  The
-** sqlite3BtreeSync() routine does the first phase and should be invoked
-** prior to calling this routine.  The sqlite3BtreeSync() routine did
-** all the work of writing information out to disk and flushing the
+** sqlite3BtreeCommitPhaseOne() routine does the first phase and should
+** be invoked prior to calling this routine.  The sqlite3BtreeCommitPhaseOne()
+** routine did all the work of writing information out to disk and flushing the
 ** contents so that they are written onto the disk platter.  All this
-** routine has to do is delete or truncate the rollback journal
-** (which causes the transaction to commit) and drop locks.
+** routine has to do is delete or truncate or zero the header in the
+** the rollback journal (which causes the transaction to commit) and
+** drop locks.
+**
+** Normally, if an error occurs while the pager layer is attempting to 
+** finalize the underlying journal file, this function returns an error and
+** the upper layer will attempt a rollback. However, if the second argument
+** is non-zero then this b-tree transaction is part of a multi-file 
+** transaction. In this case, the transaction has already been committed 
+** (by deleting a master journal file) and the caller will ignore this 
+** functions return code. So, even if an error occurs in the pager layer,
+** reset the b-tree objects internal state to indicate that the write
+** transaction has been closed. This is quite safe, as the pager will have
+** transitioned to the error state.
 **
 ** This will release the write lock on the database file.  If there
 ** are no active cursors, it also releases the read lock.
 */
-SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p){
-  BtShared *pBt = p->pBt;
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p, int bCleanup){
 
+  if( p->inTrans==TRANS_NONE ) return SQLITE_OK;
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
   btreeIntegrity(p);
 
   /* If the handle has a write-transaction open, commit the shared-btrees 
@@ -38762,37 +51142,18 @@ SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p){
   */
   if( p->inTrans==TRANS_WRITE ){
     int rc;
+    BtShared *pBt = p->pBt;
     assert( pBt->inTransaction==TRANS_WRITE );
     assert( pBt->nTransaction>0 );
     rc = sqlite3PagerCommitPhaseTwo(pBt->pPager);
-    if( rc!=SQLITE_OK ){
+    if( rc!=SQLITE_OK && bCleanup==0 ){
       sqlite3BtreeLeave(p);
       return rc;
     }
     pBt->inTransaction = TRANS_READ;
-    pBt->inStmt = 0;
-  }
-  unlockAllTables(p);
-
-  /* If the handle has any kind of transaction open, decrement the transaction
-  ** count of the shared btree. If the transaction count reaches 0, set
-  ** the shared state to TRANS_NONE. The unlockBtreeIfUnused() call below
-  ** will unlock the pager.
-  */
-  if( p->inTrans!=TRANS_NONE ){
-    pBt->nTransaction--;
-    if( 0==pBt->nTransaction ){
-      pBt->inTransaction = TRANS_NONE;
-    }
   }
 
-  /* Set the handles current transaction state to TRANS_NONE and unlock
-  ** the pager if this call closed the only read or write transaction.
-  */
-  p->inTrans = TRANS_NONE;
-  unlockBtreeIfUnused(pBt);
-
-  btreeIntegrity(p);
+  btreeEndTransaction(p);
   sqlite3BtreeLeave(p);
   return SQLITE_OK;
 }
@@ -38805,7 +51166,7 @@ SQLITE_PRIVATE int sqlite3BtreeCommit(Btree *p){
   sqlite3BtreeEnter(p);
   rc = sqlite3BtreeCommitPhaseOne(p, 0);
   if( rc==SQLITE_OK ){
-    rc = sqlite3BtreeCommitPhaseTwo(p);
+    rc = sqlite3BtreeCommitPhaseTwo(p, 0);
   }
   sqlite3BtreeLeave(p);
   return rc;
@@ -38851,12 +51212,13 @@ static int countWriteCursors(BtShared *pBt){
 */
 SQLITE_PRIVATE void sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode){
   BtCursor *p;
+  if( pBtree==0 ) return;
   sqlite3BtreeEnter(pBtree);
   for(p=pBtree->pBt->pCursor; p; p=p->pNext){
     int i;
     sqlite3BtreeClearCursor(p);
     p->eState = CURSOR_FAULT;
-    p->skip = errCode;
+    p->skipNext = errCode;
     for(i=0; i<=p->iPage; i++){
       releasePage(p->apPage[i]);
       p->apPage[i] = 0;
@@ -38874,28 +51236,21 @@ SQLITE_PRIVATE void sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode){
 ** This will release the write lock on the database file.  If there
 ** are no active cursors, it also releases the read lock.
 */
-SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p){
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p, int tripCode){
   int rc;
   BtShared *pBt = p->pBt;
   MemPage *pPage1;
 
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
-  rc = saveAllCursors(pBt, 0, 0);
-#ifndef SQLITE_OMIT_SHARED_CACHE
-  if( rc!=SQLITE_OK ){
-    /* This is a horrible situation. An IO or malloc() error occured whilst
-    ** trying to save cursor positions. If this is an automatic rollback (as
-    ** the result of a constraint, malloc() failure or IO error) then 
-    ** the cache may be internally inconsistent (not contain valid trees) so
-    ** we cannot simply return the error to the caller. Instead, abort 
-    ** all queries that may be using any of the cursors that failed to save.
-    */
-    sqlite3BtreeTripAllCursors(p, rc);
+  if( tripCode==SQLITE_OK ){
+    rc = tripCode = saveAllCursors(pBt, 0, 0);
+  }else{
+    rc = SQLITE_OK;
+  }
+  if( tripCode ){
+    sqlite3BtreeTripAllCursors(p, tripCode);
   }
-#endif
   btreeIntegrity(p);
-  unlockAllTables(p);
 
   if( p->inTrans==TRANS_WRITE ){
     int rc2;
@@ -38907,114 +51262,58 @@ SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p){
     }
 
     /* The rollback may have destroyed the pPage1->aData value.  So
-    ** call sqlite3BtreeGetPage() on page 1 again to make
+    ** call btreeGetPage() on page 1 again to make
     ** sure pPage1->aData is set correctly. */
-    if( sqlite3BtreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
+    if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
+      int nPage = get4byte(28+(u8*)pPage1->aData);
+      testcase( nPage==0 );
+      if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage);
+      testcase( pBt->nPage!=nPage );
+      pBt->nPage = nPage;
       releasePage(pPage1);
     }
     assert( countWriteCursors(pBt)==0 );
     pBt->inTransaction = TRANS_READ;
   }
 
-  if( p->inTrans!=TRANS_NONE ){
-    assert( pBt->nTransaction>0 );
-    pBt->nTransaction--;
-    if( 0==pBt->nTransaction ){
-      pBt->inTransaction = TRANS_NONE;
-    }
-  }
-
-  p->inTrans = TRANS_NONE;
-  pBt->inStmt = 0;
-  unlockBtreeIfUnused(pBt);
-
-  btreeIntegrity(p);
+  btreeEndTransaction(p);
   sqlite3BtreeLeave(p);
   return rc;
 }
 
 /*
-** Start a statement subtransaction.  The subtransaction can
-** can be rolled back independently of the main transaction.
-** You must start a transaction before starting a subtransaction.
-** The subtransaction is ended automatically if the main transaction
-** commits or rolls back.
-**
-** Only one subtransaction may be active at a time.  It is an error to try
-** to start a new subtransaction if another subtransaction is already active.
+** Start a statement subtransaction. The subtransaction can can be rolled
+** back independently of the main transaction. You must start a transaction 
+** before starting a subtransaction. The subtransaction is ended automatically 
+** if the main transaction commits or rolls back.
 **
 ** Statement subtransactions are used around individual SQL statements
 ** that are contained within a BEGIN...COMMIT block.  If a constraint
 ** error occurs within the statement, the effect of that one statement
 ** can be rolled back without having to rollback the entire transaction.
-*/
-SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree *p){
-  int rc;
-  BtShared *pBt = p->pBt;
-  sqlite3BtreeEnter(p);
-  pBt->db = p->db;
-  assert( p->inTrans==TRANS_WRITE );
-  assert( !pBt->inStmt );
-  assert( pBt->readOnly==0 );
-  if( NEVER(p->inTrans!=TRANS_WRITE || pBt->inStmt || pBt->readOnly) ){
-    rc = SQLITE_INTERNAL;
-  }else{
-    assert( pBt->inTransaction==TRANS_WRITE );
-    /* At the pager level, a statement transaction is a savepoint with
-    ** an index greater than all savepoints created explicitly using
-    ** SQL statements. It is illegal to open, release or rollback any
-    ** such savepoints while the statement transaction savepoint is active.
-    */
-    rc = sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint+1);
-    pBt->inStmt = 1;
-  }
-  sqlite3BtreeLeave(p);
-  return rc;
-}
-
-/*
-** Commit the statment subtransaction currently in progress.  If no
-** subtransaction is active, this is a no-op.
-*/
-SQLITE_PRIVATE int sqlite3BtreeCommitStmt(Btree *p){
-  int rc;
-  BtShared *pBt = p->pBt;
-  sqlite3BtreeEnter(p);
-  pBt->db = p->db;
-  assert( pBt->readOnly==0 );
-  if( pBt->inStmt ){
-    int iStmtpoint = p->db->nSavepoint;
-    rc = sqlite3PagerSavepoint(pBt->pPager, SAVEPOINT_RELEASE, iStmtpoint);
-  }else{
-    rc = SQLITE_OK;
-  }
-  pBt->inStmt = 0;
-  sqlite3BtreeLeave(p);
-  return rc;
-}
-
-/*
-** Rollback the active statement subtransaction.  If no subtransaction
-** is active this routine is a no-op.
 **
-** All cursors will be invalidated by this operation.  Any attempt
-** to use a cursor that was open at the beginning of this operation
-** will result in an error.
+** A statement sub-transaction is implemented as an anonymous savepoint. The
+** value passed as the second parameter is the total number of savepoints,
+** including the new anonymous savepoint, open on the B-Tree. i.e. if there
+** are no active savepoints and no other statement-transactions open,
+** iStatement is 1. This anonymous savepoint can be released or rolled back
+** using the sqlite3BtreeSavepoint() function.
 */
-SQLITE_PRIVATE int sqlite3BtreeRollbackStmt(Btree *p){
-  int rc = SQLITE_OK;
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree *p, int iStatement){
+  int rc;
   BtShared *pBt = p->pBt;
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
-  assert( pBt->readOnly==0 );
-  if( pBt->inStmt ){
-    int iStmtpoint = p->db->nSavepoint;
-    rc = sqlite3PagerSavepoint(pBt->pPager, SAVEPOINT_ROLLBACK, iStmtpoint);
-    if( rc==SQLITE_OK ){
-      rc = sqlite3PagerSavepoint(pBt->pPager, SAVEPOINT_RELEASE, iStmtpoint);
-    }
-    pBt->inStmt = 0;
-  }
+  assert( p->inTrans==TRANS_WRITE );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( iStatement>0 );
+  assert( iStatement>p->db->nSavepoint );
+  assert( pBt->inTransaction==TRANS_WRITE );
+  /* At the pager level, a statement transaction is a savepoint with
+  ** an index greater than all savepoints created explicitly using
+  ** SQL statements. It is illegal to open, release or rollback any
+  ** such savepoints while the statement transaction savepoint is active.
+  */
+  rc = sqlite3PagerOpenSavepoint(pBt->pPager, iStatement);
   sqlite3BtreeLeave(p);
   return rc;
 }
@@ -39035,14 +51334,21 @@ SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
   int rc = SQLITE_OK;
   if( p && p->inTrans==TRANS_WRITE ){
     BtShared *pBt = p->pBt;
-    assert( pBt->inStmt==0 );
     assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
     assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
     sqlite3BtreeEnter(p);
-    pBt->db = p->db;
     rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
     if( rc==SQLITE_OK ){
+      if( iSavepoint<0 && (pBt->btsFlags & BTS_INITIALLY_EMPTY)!=0 ){
+        pBt->nPage = 0;
+      }
       rc = newDatabase(pBt);
+      pBt->nPage = get4byte(28 + pBt->pPage1->aData);
+
+      /* The database size was written into the offset 28 of the header
+      ** when the transaction started, so we know that the value at offset
+      ** 28 is nonzero. */
+      assert( pBt->nPage>0 );
     }
     sqlite3BtreeLeave(p);
   }
@@ -39051,8 +51357,10 @@ SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
 
 /*
 ** Create a new cursor for the BTree whose root is on the page
-** iTable.  The act of acquiring a cursor gets a read lock on 
-** the database file.
+** iTable. If a read-only cursor is requested, it is assumed that
+** the caller already has at least a read-only transaction open
+** on the database already. If a write-cursor is requested, then
+** the caller is assumed to have an open write transaction.
 **
 ** If wrFlag==0, then the cursor can only be used for reading.
 ** If wrFlag==1, then the cursor can be used for reading or for
@@ -39076,8 +51384,8 @@ SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
 ** root page of a b-tree.  If it is not, then the cursor acquired
 ** will not work correctly.
 **
-** It is assumed that the sqlite3BtreeCursorSize() bytes of memory 
-** pointed to by pCur have been zeroed by the caller.
+** It is assumed that the sqlite3BtreeCursorZero() has been called
+** on pCur to initialize the memory space prior to invoking this routine.
 */
 static int btreeCursor(
   Btree *p,                              /* The btree */
@@ -39086,46 +51394,35 @@ static int btreeCursor(
   struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
   BtCursor *pCur                         /* Space for new cursor */
 ){
-  int rc;
-  Pgno nPage;
-  BtShared *pBt = p->pBt;
+  BtShared *pBt = p->pBt;                /* Shared b-tree handle */
 
   assert( sqlite3BtreeHoldsMutex(p) );
   assert( wrFlag==0 || wrFlag==1 );
-  if( wrFlag ){
-    assert( !pBt->readOnly );
-    if( NEVER(pBt->readOnly) ){
-      return SQLITE_READONLY;
-    }
-    if( checkReadLocks(p, iTable, 0, 0) ){
-      return SQLITE_LOCKED;
-    }
-  }
 
-  if( pBt->pPage1==0 ){
-    rc = lockBtreeWithRetry(p);
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
+  /* The following assert statements verify that if this is a sharable 
+  ** b-tree database, the connection is holding the required table locks, 
+  ** and that no other connection has any open cursor that conflicts with 
+  ** this lock.  */
+  assert( hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, wrFlag+1) );
+  assert( wrFlag==0 || !hasReadConflicts(p, iTable) );
+
+  /* Assert that the caller has opened the required transaction. */
+  assert( p->inTrans>TRANS_NONE );
+  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
+  assert( pBt->pPage1 && pBt->pPage1->aData );
+
+  if( NEVER(wrFlag && (pBt->btsFlags & BTS_READ_ONLY)!=0) ){
+    return SQLITE_READONLY;
   }
-  pCur->pgnoRoot = (Pgno)iTable;
-  rc = sqlite3PagerPagecount(pBt->pPager, (int *)&nPage); 
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
-  if( iTable==1 && nPage==0 ){
-    rc = SQLITE_EMPTY;
-    goto create_cursor_exception;
-  }
-  rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->apPage[0]);
-  if( rc!=SQLITE_OK ){
-    goto create_cursor_exception;
+  if( iTable==1 && btreePagecount(pBt)==0 ){
+    assert( wrFlag==0 );
+    iTable = 0;
   }
 
   /* Now that no other errors can occur, finish filling in the BtCursor
-  ** variables, link the cursor into the BtShared list and set *ppCur (the
-  ** output argument to this function).
-  */
+  ** variables and link the cursor into the BtShared list.  */
+  pCur->pgnoRoot = (Pgno)iTable;
+  pCur->iPage = -1;
   pCur->pKeyInfo = pKeyInfo;
   pCur->pBtree = p;
   pCur->pBt = pBt;
@@ -39136,13 +51433,8 @@ static int btreeCursor(
   }
   pBt->pCursor = pCur;
   pCur->eState = CURSOR_INVALID;
-
+  pCur->cachedRowid = 0;
   return SQLITE_OK;
-
-create_cursor_exception:
-  releasePage(pCur->apPage[0]);
-  unlockBtreeIfUnused(pBt);
-  return rc;
 }
 SQLITE_PRIVATE int sqlite3BtreeCursor(
   Btree *p,                                   /* The btree */
@@ -39153,16 +51445,64 @@ SQLITE_PRIVATE int sqlite3BtreeCursor(
 ){
   int rc;
   sqlite3BtreeEnter(p);
-  p->pBt->db = p->db;
   rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
   sqlite3BtreeLeave(p);
   return rc;
 }
-SQLITE_PRIVATE int sqlite3BtreeCursorSize(){
-  return sizeof(BtCursor);
+
+/*
+** Return the size of a BtCursor object in bytes.
+**
+** This interfaces is needed so that users of cursors can preallocate
+** sufficient storage to hold a cursor.  The BtCursor object is opaque
+** to users so they cannot do the sizeof() themselves - they must call
+** this routine.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorSize(void){
+  return ROUND8(sizeof(BtCursor));
 }
 
+/*
+** Initialize memory that will be converted into a BtCursor object.
+**
+** The simple approach here would be to memset() the entire object
+** to zero.  But it turns out that the apPage[] and aiIdx[] arrays
+** do not need to be zeroed and they are large, so we can save a lot
+** of run-time by skipping the initialization of those elements.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor *p){
+  memset(p, 0, offsetof(BtCursor, iPage));
+}
 
+/*
+** Set the cached rowid value of every cursor in the same database file
+** as pCur and having the same root page number as pCur.  The value is
+** set to iRowid.
+**
+** Only positive rowid values are considered valid for this cache.
+** The cache is initialized to zero, indicating an invalid cache.
+** A btree will work fine with zero or negative rowids.  We just cannot
+** cache zero or negative rowids, which means tables that use zero or
+** negative rowids might run a little slower.  But in practice, zero
+** or negative rowids are very uncommon so this should not be a problem.
+*/
+SQLITE_PRIVATE void sqlite3BtreeSetCachedRowid(BtCursor *pCur, sqlite3_int64 iRowid){
+  BtCursor *p;
+  for(p=pCur->pBt->pCursor; p; p=p->pNext){
+    if( p->pgnoRoot==pCur->pgnoRoot ) p->cachedRowid = iRowid;
+  }
+  assert( pCur->cachedRowid==iRowid );
+}
+
+/*
+** Return the cached rowid for the given cursor.  A negative or zero
+** return value indicates that the rowid cache is invalid and should be
+** ignored.  If the rowid cache has never before been set, then a
+** zero is returned.
+*/
+SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeGetCachedRowid(BtCursor *pCur){
+  return pCur->cachedRowid;
+}
 
 /*
 ** Close a cursor.  The read lock on the database file is released
@@ -39174,7 +51514,6 @@ SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
     int i;
     BtShared *pBt = pCur->pBt;
     sqlite3BtreeEnter(pBtree);
-    pBt->db = pBtree->db;
     sqlite3BtreeClearCursor(pCur);
     if( pCur->pPrev ){
       pCur->pPrev->pNext = pCur->pNext;
@@ -39195,42 +51534,13 @@ SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
   return SQLITE_OK;
 }
 
-/*
-** Make a temporary cursor by filling in the fields of pTempCur.
-** The temporary cursor is not on the cursor list for the Btree.
-*/
-SQLITE_PRIVATE void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur){
-  int i;
-  assert( cursorHoldsMutex(pCur) );
-  memcpy(pTempCur, pCur, sizeof(BtCursor));
-  pTempCur->pNext = 0;
-  pTempCur->pPrev = 0;
-  for(i=0; i<=pTempCur->iPage; i++){
-    sqlite3PagerRef(pTempCur->apPage[i]->pDbPage);
-  }
-  assert( pTempCur->pKey==0 );
-}
-
-/*
-** Delete a temporary cursor such as was made by the CreateTemporaryCursor()
-** function above.
-*/
-SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur){
-  int i;
-  assert( cursorHoldsMutex(pCur) );
-  for(i=0; i<=pCur->iPage; i++){
-    sqlite3PagerUnref(pCur->apPage[i]->pDbPage);
-  }
-  sqlite3_free(pCur->pKey);
-}
-
 /*
 ** Make sure the BtCursor* given in the argument has a valid
 ** BtCursor.info structure.  If it is not already valid, call
-** sqlite3BtreeParseCell() to fill it in.
+** btreeParseCell() to fill it in.
 **
 ** BtCursor.info is a cache of the information in the current cell.
-** Using this cache reduces the number of calls to sqlite3BtreeParseCell().
+** Using this cache reduces the number of calls to btreeParseCell().
 **
 ** 2007-06-25:  There is a bug in some versions of MSVC that cause the
 ** compiler to crash when getCellInfo() is implemented as a macro.
@@ -39244,7 +51554,7 @@ SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur){
     CellInfo info;
     int iPage = pCur->iPage;
     memset(&info, 0, sizeof(info));
-    sqlite3BtreeParseCell(pCur->apPage[iPage], pCur->aiIdx[iPage], &info);
+    btreeParseCell(pCur->apPage[iPage], pCur->aiIdx[iPage], &info);
     assert( memcmp(&info, &pCur->info, sizeof(info))==0 );
   }
 #else
@@ -39255,7 +51565,7 @@ SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur){
   static void getCellInfo(BtCursor *pCur){
     if( pCur->info.nSize==0 ){
       int iPage = pCur->iPage;
-      sqlite3BtreeParseCell(pCur->apPage[iPage],pCur->aiIdx[iPage],&pCur->info);
+      btreeParseCell(pCur->apPage[iPage],pCur->aiIdx[iPage],&pCur->info);
       pCur->validNKey = 1;
     }else{
       assertCellInfo(pCur);
@@ -39266,13 +51576,24 @@ SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur){
 #define getCellInfo(pCur)                                                      \
   if( pCur->info.nSize==0 ){                                                   \
     int iPage = pCur->iPage;                                                   \
-    sqlite3BtreeParseCell(pCur->apPage[iPage],pCur->aiIdx[iPage],&pCur->info); \
+    btreeParseCell(pCur->apPage[iPage],pCur->aiIdx[iPage],&pCur->info); \
     pCur->validNKey = 1;                                                       \
   }else{                                                                       \
     assertCellInfo(pCur);                                                      \
   }
 #endif /* _MSC_VER */
 
+#ifndef NDEBUG  /* The next routine used only within assert() statements */
+/*
+** Return true if the given BtCursor is valid.  A valid cursor is one
+** that is currently pointing to a row in a (non-empty) table.
+** This is a verification routine is used only within assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor *pCur){
+  return pCur && pCur->eState==CURSOR_VALID;
+}
+#endif /* NDEBUG */
+
 /*
 ** Set *pSize to the size of the buffer needed to hold the value of
 ** the key for the current entry.  If the cursor is not pointing
@@ -39280,47 +51601,41 @@ SQLITE_PRIVATE void sqlite3BtreeReleaseTempCursor(BtCursor *pCur){
 **
 ** For a table with the INTKEY flag set, this routine returns the key
 ** itself, not the number of bytes in the key.
+**
+** The caller must position the cursor prior to invoking this routine.
+** 
+** This routine cannot fail.  It always returns SQLITE_OK.  
 */
 SQLITE_PRIVATE int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
-  int rc;
-
   assert( cursorHoldsMutex(pCur) );
-  rc = restoreCursorPosition(pCur);
-  if( rc==SQLITE_OK ){
-    assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
-    if( pCur->eState==CURSOR_INVALID ){
-      *pSize = 0;
-    }else{
-      getCellInfo(pCur);
-      *pSize = pCur->info.nKey;
-    }
+  assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
+  if( pCur->eState!=CURSOR_VALID ){
+    *pSize = 0;
+  }else{
+    getCellInfo(pCur);
+    *pSize = pCur->info.nKey;
   }
-  return rc;
+  return SQLITE_OK;
 }
 
 /*
 ** Set *pSize to the number of bytes of data in the entry the
-** cursor currently points to.  Always return SQLITE_OK.
-** Failure is not possible.  If the cursor is not currently
-** pointing to an entry (which can happen, for example, if
-** the database is empty) then *pSize is set to 0.
+** cursor currently points to.
+**
+** The caller must guarantee that the cursor is pointing to a non-NULL
+** valid entry.  In other words, the calling procedure must guarantee
+** that the cursor has Cursor.eState==CURSOR_VALID.
+**
+** Failure is not possible.  This function always returns SQLITE_OK.
+** It might just as well be a procedure (returning void) but we continue
+** to return an integer result code for historical reasons.
 */
 SQLITE_PRIVATE int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
-  int rc;
-
   assert( cursorHoldsMutex(pCur) );
-  rc = restoreCursorPosition(pCur);
-  if( rc==SQLITE_OK ){
-    assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
-    if( pCur->eState==CURSOR_INVALID ){
-      /* Not pointing at a valid entry - set *pSize to 0. */
-      *pSize = 0;
-    }else{
-      getCellInfo(pCur);
-      *pSize = pCur->info.nData;
-    }
-  }
-  return rc;
+  assert( pCur->eState==CURSOR_VALID );
+  getCellInfo(pCur);
+  *pSize = pCur->info.nData;
+  return SQLITE_OK;
 }
 
 /*
@@ -39331,34 +51646,29 @@ SQLITE_PRIVATE int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
 **
 ** If an error occurs an SQLite error code is returned. Otherwise:
 **
-** Unless pPgnoNext is NULL, the page number of the next overflow 
-** page in the linked list is written to *pPgnoNext. If page ovfl
-** is the last page in its linked list, *pPgnoNext is set to zero. 
+** The page number of the next overflow page in the linked list is 
+** written to *pPgnoNext. If page ovfl is the last page in its linked 
+** list, *pPgnoNext is set to zero. 
 **
-** If ppPage is not NULL, *ppPage is set to the MemPage* handle
-** for page ovfl. The underlying pager page may have been requested
-** with the noContent flag set, so the page data accessable via
-** this handle may not be trusted.
+** If ppPage is not NULL, and a reference to the MemPage object corresponding
+** to page number pOvfl was obtained, then *ppPage is set to point to that
+** reference. It is the responsibility of the caller to call releasePage()
+** on *ppPage to free the reference. In no reference was obtained (because
+** the pointer-map was used to obtain the value for *pPgnoNext), then
+** *ppPage is set to zero.
 */
 static int getOverflowPage(
-  BtShared *pBt, 
-  Pgno ovfl,                   /* Overflow page */
-  MemPage **ppPage,            /* OUT: MemPage handle */
+  BtShared *pBt,               /* The database file */
+  Pgno ovfl,                   /* Current overflow page number */
+  MemPage **ppPage,            /* OUT: MemPage handle (may be NULL) */
   Pgno *pPgnoNext              /* OUT: Next overflow page number */
 ){
   Pgno next = 0;
+  MemPage *pPage = 0;
   int rc = SQLITE_OK;
 
   assert( sqlite3_mutex_held(pBt->mutex) );
-  /* One of these must not be NULL. Otherwise, why call this function? */
-  assert(ppPage || pPgnoNext);
-
-  /* If pPgnoNext is NULL, then this function is being called to obtain
-  ** a MemPage* reference only. No page-data is required in this case.
-  */
-  if( !pPgnoNext ){
-    return sqlite3BtreeGetPage(pBt, ovfl, ppPage, 1);
-  }
+  assert(pPgnoNext);
 
 #ifndef SQLITE_OMIT_AUTOVACUUM
   /* Try to find the next page in the overflow list using the
@@ -39376,36 +51686,32 @@ static int getOverflowPage(
       iGuess++;
     }
 
-    if( iGuess<=pagerPagecount(pBt) ){
+    if( iGuess<=btreePagecount(pBt) ){
       rc = ptrmapGet(pBt, iGuess, &eType, &pgno);
-      if( rc!=SQLITE_OK ){
-        return rc;
-      }
-      if( eType==PTRMAP_OVERFLOW2 && pgno==ovfl ){
+      if( rc==SQLITE_OK && eType==PTRMAP_OVERFLOW2 && pgno==ovfl ){
         next = iGuess;
+        rc = SQLITE_DONE;
       }
     }
   }
 #endif
 
-  if( next==0 || ppPage ){
-    MemPage *pPage = 0;
-
-    rc = sqlite3BtreeGetPage(pBt, ovfl, &pPage, next!=0);
-    assert(rc==SQLITE_OK || pPage==0);
-    if( next==0 && rc==SQLITE_OK ){
+  assert( next==0 || rc==SQLITE_DONE );
+  if( rc==SQLITE_OK ){
+    rc = btreeGetPage(pBt, ovfl, &pPage, 0);
+    assert( rc==SQLITE_OK || pPage==0 );
+    if( rc==SQLITE_OK ){
       next = get4byte(pPage->aData);
     }
-
-    if( ppPage ){
-      *ppPage = pPage;
-    }else{
-      releasePage(pPage);
-    }
   }
-  *pPgnoNext = next;
 
-  return rc;
+  *pPgnoNext = next;
+  if( ppPage ){
+    *ppPage = pPage;
+  }else{
+    releasePage(pPage);
+  }
+  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
 }
 
 /*
@@ -39450,10 +51756,8 @@ static int copyPayload(
 ** A total of "amt" bytes are read or written beginning at "offset".
 ** Data is read to or from the buffer pBuf.
 **
-** This routine does not make a distinction between key and data.
-** It just reads or writes bytes from the payload area.  Data might 
-** appear on the main page or be scattered out on multiple overflow 
-** pages.
+** The content being read or written might appear on the main page
+** or be scattered out on multiple overflow pages.
 **
 ** If the BtCursor.isIncrblobHandle flag is set, and the current
 ** cursor entry uses one or more overflow pages, this function
@@ -39475,7 +51779,6 @@ static int accessPayload(
   u32 offset,          /* Begin reading this far into payload */
   u32 amt,             /* Read this many bytes */
   unsigned char *pBuf, /* Write the bytes into this buffer */ 
-  int skipKey,         /* offset begins at data if this is true */
   int eOp              /* zero to read. non-zero to write. */
 ){
   unsigned char *aPayload;
@@ -39494,10 +51797,7 @@ static int accessPayload(
   aPayload = pCur->info.pCell + pCur->info.nHeader;
   nKey = (pPage->intKey ? 0 : (int)pCur->info.nKey);
 
-  if( skipKey ){
-    offset += nKey;
-  }
-  if( offset+amt > nKey+pCur->info.nData 
+  if( NEVER(offset+amt > nKey+pCur->info.nData) 
    || &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
   ){
     /* Trying to read or write past the end of the data is an error */
@@ -39535,7 +51835,9 @@ static int accessPayload(
     if( pCur->isIncrblobHandle && !pCur->aOverflow ){
       int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
       pCur->aOverflow = (Pgno *)sqlite3MallocZero(sizeof(Pgno)*nOvfl);
-      if( nOvfl && !pCur->aOverflow ){
+      /* nOvfl is always positive.  If it were zero, fetchPayload would have
+      ** been used instead of this routine. */
+      if( ALWAYS(nOvfl) && !pCur->aOverflow ){
         rc = SQLITE_NOMEM;
       }
     }
@@ -39579,21 +51881,55 @@ static int accessPayload(
         /* Need to read this page properly. It contains some of the
         ** range of data that is being read (eOp==0) or written (eOp!=0).
         */
-        DbPage *pDbPage;
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+        sqlite3_file *fd;
+#endif
         int a = amt;
-        rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage);
-        if( rc==SQLITE_OK ){
-          aPayload = sqlite3PagerGetData(pDbPage);
-          nextPage = get4byte(aPayload);
-          if( a + offset > ovflSize ){
-            a = ovflSize - offset;
-          }
-          rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
-          sqlite3PagerUnref(pDbPage);
-          offset = 0;
-          amt -= a;
-          pBuf += a;
+        if( a + offset > ovflSize ){
+          a = ovflSize - offset;
         }
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+        /* If all the following are true:
+        **
+        **   1) this is a read operation, and 
+        **   2) data is required from the start of this overflow page, and
+        **   3) the database is file-backed, and
+        **   4) there is no open write-transaction, and
+        **   5) the database is not a WAL database,
+        **
+        ** then data can be read directly from the database file into the
+        ** output buffer, bypassing the page-cache altogether. This speeds
+        ** up loading large records that span many overflow pages.
+        */
+        if( eOp==0                                             /* (1) */
+         && offset==0                                          /* (2) */
+         && pBt->inTransaction==TRANS_READ                     /* (4) */
+         && (fd = sqlite3PagerFile(pBt->pPager))->pMethods     /* (3) */
+         && pBt->pPage1->aData[19]==0x01                       /* (5) */
+        ){
+          u8 aSave[4];
+          u8 *aWrite = &pBuf[-4];
+          memcpy(aSave, aWrite, 4);
+          rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1));
+          nextPage = get4byte(aWrite);
+          memcpy(aWrite, aSave, 4);
+        }else
+#endif
+
+        {
+          DbPage *pDbPage;
+          rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage);
+          if( rc==SQLITE_OK ){
+            aPayload = sqlite3PagerGetData(pDbPage);
+            nextPage = get4byte(aPayload);
+            rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
+            sqlite3PagerUnref(pDbPage);
+            offset = 0;
+          }
+        }
+        amt -= a;
+        pBuf += a;
       }
     }
   }
@@ -39609,25 +51945,19 @@ static int accessPayload(
 ** "amt" bytes will be transfered into pBuf[].  The transfer
 ** begins at "offset".
 **
+** The caller must ensure that pCur is pointing to a valid row
+** in the table.
+**
 ** Return SQLITE_OK on success or an error code if anything goes
 ** wrong.  An error is returned if "offset+amt" is larger than
 ** the available payload.
 */
 SQLITE_PRIVATE int sqlite3BtreeKey(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
-  int rc;
-
   assert( cursorHoldsMutex(pCur) );
-  rc = restoreCursorPosition(pCur);
-  if( rc==SQLITE_OK ){
-    assert( pCur->eState==CURSOR_VALID );
-    assert( pCur->iPage>=0 && pCur->apPage[pCur->iPage] );
-    if( pCur->apPage[0]->intKey ){
-      return SQLITE_CORRUPT_BKPT;
-    }
-    assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
-    rc = accessPayload(pCur, offset, amt, (unsigned char*)pBuf, 0, 0);
-  }
-  return rc;
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->iPage>=0 && pCur->apPage[pCur->iPage] );
+  assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
+  return accessPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
 }
 
 /*
@@ -39654,7 +51984,7 @@ SQLITE_PRIVATE int sqlite3BtreeData(BtCursor *pCur, u32 offset, u32 amt, void *p
     assert( pCur->eState==CURSOR_VALID );
     assert( pCur->iPage>=0 && pCur->apPage[pCur->iPage] );
     assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
-    rc = accessPayload(pCur, offset, amt, pBuf, 1, 0);
+    rc = accessPayload(pCur, offset, amt, pBuf, 0);
   }
   return rc;
 }
@@ -39671,7 +52001,7 @@ SQLITE_PRIVATE int sqlite3BtreeData(BtCursor *pCur, u32 offset, u32 amt, void *p
 ** and data to fit on the local page and for there to be no overflow
 ** pages.  When that is so, this routine can be used to access the
 ** key and data without making a copy.  If the key and/or data spills
-** onto overflow pages, then accessPayload() must be used to reassembly
+** onto overflow pages, then accessPayload() must be used to reassemble
 ** the key/data and copy it into a preallocated buffer.
 **
 ** The pointer returned by this routine looks directly into the cached
@@ -39693,7 +52023,10 @@ static const unsigned char *fetchPayload(
   assert( cursorHoldsMutex(pCur) );
   pPage = pCur->apPage[pCur->iPage];
   assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
-  getCellInfo(pCur);
+  if( NEVER(pCur->info.nSize==0) ){
+    btreeParseCell(pCur->apPage[pCur->iPage], pCur->aiIdx[pCur->iPage],
+                   &pCur->info);
+  }
   aPayload = pCur->info.pCell;
   aPayload += pCur->info.nHeader;
   if( pPage->intKey ){
@@ -39706,9 +52039,7 @@ static const unsigned char *fetchPayload(
     nLocal = pCur->info.nLocal - nKey;
   }else{
     nLocal = pCur->info.nLocal;
-    if( nLocal>nKey ){
-      nLocal = nKey;
-    }
+    assert( nLocal<=nKey );
   }
   *pAmt = nLocal;
   return aPayload;
@@ -39730,24 +52061,33 @@ static const unsigned char *fetchPayload(
 ** in the common case where no overflow pages are used.
 */
 SQLITE_PRIVATE const void *sqlite3BtreeKeyFetch(BtCursor *pCur, int *pAmt){
+  const void *p = 0;
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
   assert( cursorHoldsMutex(pCur) );
-  if( pCur->eState==CURSOR_VALID ){
-    return (const void*)fetchPayload(pCur, pAmt, 0);
+  if( ALWAYS(pCur->eState==CURSOR_VALID) ){
+    p = (const void*)fetchPayload(pCur, pAmt, 0);
   }
-  return 0;
+  return p;
 }
 SQLITE_PRIVATE const void *sqlite3BtreeDataFetch(BtCursor *pCur, int *pAmt){
+  const void *p = 0;
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
   assert( cursorHoldsMutex(pCur) );
-  if( pCur->eState==CURSOR_VALID ){
-    return (const void*)fetchPayload(pCur, pAmt, 1);
+  if( ALWAYS(pCur->eState==CURSOR_VALID) ){
+    p = (const void*)fetchPayload(pCur, pAmt, 1);
   }
-  return 0;
+  return p;
 }
 
 
 /*
 ** Move the cursor down to a new child page.  The newPgno argument is the
 ** page number of the child page to move to.
+**
+** This function returns SQLITE_CORRUPT if the page-header flags field of
+** the new child page does not match the flags field of the parent (i.e.
+** if an intkey page appears to be the parent of a non-intkey page, or
+** vice-versa).
 */
 static int moveToChild(BtCursor *pCur, u32 newPgno){
   int rc;
@@ -39769,13 +52109,13 @@ static int moveToChild(BtCursor *pCur, u32 newPgno){
 
   pCur->info.nSize = 0;
   pCur->validNKey = 0;
-  if( pNewPage->nCell<1 ){
+  if( pNewPage->nCell<1 || pNewPage->intKey!=pCur->apPage[i]->intKey ){
     return SQLITE_CORRUPT_BKPT;
   }
   return SQLITE_OK;
 }
 
-#ifndef NDEBUG
+#if 0
 /*
 ** Page pParent is an internal (non-leaf) tree page. This function 
 ** asserts that page number iChild is the left-child if the iIdx'th
@@ -39803,16 +52143,26 @@ static void assertParentIndex(MemPage *pParent, int iIdx, Pgno iChild){
 ** right-most child page then pCur->idx is set to one more than
 ** the largest cell index.
 */
-SQLITE_PRIVATE void sqlite3BtreeMoveToParent(BtCursor *pCur){
+static void moveToParent(BtCursor *pCur){
   assert( cursorHoldsMutex(pCur) );
   assert( pCur->eState==CURSOR_VALID );
   assert( pCur->iPage>0 );
   assert( pCur->apPage[pCur->iPage] );
+
+  /* UPDATE: It is actually possible for the condition tested by the assert
+  ** below to be untrue if the database file is corrupt. This can occur if
+  ** one cursor has modified page pParent while a reference to it is held 
+  ** by a second cursor. Which can only happen if a single page is linked
+  ** into more than one b-tree structure in a corrupt database.  */
+#if 0
   assertParentIndex(
     pCur->apPage[pCur->iPage-1], 
     pCur->aiIdx[pCur->iPage-1], 
     pCur->apPage[pCur->iPage]->pgno
   );
+#endif
+  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );
+
   releasePage(pCur->apPage[pCur->iPage]);
   pCur->iPage--;
   pCur->info.nSize = 0;
@@ -39820,7 +52170,25 @@ SQLITE_PRIVATE void sqlite3BtreeMoveToParent(BtCursor *pCur){
 }
 
 /*
-** Move the cursor to the root page
+** Move the cursor to point to the root page of its b-tree structure.
+**
+** If the table has a virtual root page, then the cursor is moved to point
+** to the virtual root page instead of the actual root page. A table has a
+** virtual root page when the actual root page contains no cells and a 
+** single child page. This can only happen with the table rooted at page 1.
+**
+** If the b-tree structure is empty, the cursor state is set to 
+** CURSOR_INVALID. Otherwise, the cursor is set to point to the first
+** cell located on the root (or virtual root) page and the cursor state
+** is set to CURSOR_VALID.
+**
+** If this function returns successfully, it may be assumed that the
+** page-header flags indicate that the [virtual] root-page is the expected 
+** kind of b-tree page (i.e. if when opening the cursor the caller did not
+** specify a KeyInfo structure the flags byte is set to 0x05 or 0x0D,
+** indicating a table b-tree, or if the caller did specify a KeyInfo 
+** structure the flags byte is set to 0x02 or 0x0A, indicating an index
+** b-tree).
 */
 static int moveToRoot(BtCursor *pCur){
   MemPage *pRoot;
@@ -39834,7 +52202,8 @@ static int moveToRoot(BtCursor *pCur){
   assert( CURSOR_FAULT   > CURSOR_REQUIRESEEK );
   if( pCur->eState>=CURSOR_REQUIRESEEK ){
     if( pCur->eState==CURSOR_FAULT ){
-      return pCur->skip;
+      assert( pCur->skipNext!=SQLITE_OK );
+      return pCur->skipNext;
     }
     sqlite3BtreeClearCursor(pCur);
   }
@@ -39844,18 +52213,38 @@ static int moveToRoot(BtCursor *pCur){
     for(i=1; i<=pCur->iPage; i++){
       releasePage(pCur->apPage[i]);
     }
+    pCur->iPage = 0;
+  }else if( pCur->pgnoRoot==0 ){
+    pCur->eState = CURSOR_INVALID;
+    return SQLITE_OK;
   }else{
-    if( 
-      SQLITE_OK!=(rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->apPage[0]))
-    ){
+    rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->apPage[0]);
+    if( rc!=SQLITE_OK ){
       pCur->eState = CURSOR_INVALID;
       return rc;
     }
+    pCur->iPage = 0;
+
+    /* If pCur->pKeyInfo is not NULL, then the caller that opened this cursor
+    ** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
+    ** NULL, the caller expects a table b-tree. If this is not the case,
+    ** return an SQLITE_CORRUPT error.  */
+    assert( pCur->apPage[0]->intKey==1 || pCur->apPage[0]->intKey==0 );
+    if( (pCur->pKeyInfo==0)!=pCur->apPage[0]->intKey ){
+      return SQLITE_CORRUPT_BKPT;
+    }
   }
 
+  /* Assert that the root page is of the correct type. This must be the
+  ** case as the call to this function that loaded the root-page (either
+  ** this call or a previous invocation) would have detected corruption 
+  ** if the assumption were not true, and it is not possible for the flags 
+  ** byte to have been modified while this cursor is holding a reference
+  ** to the page.  */
   pRoot = pCur->apPage[0];
   assert( pRoot->pgno==pCur->pgnoRoot );
-  pCur->iPage = 0;
+  assert( pRoot->isInit && (pCur->pKeyInfo==0)==pRoot->intKey );
+
   pCur->aiIdx[0] = 0;
   pCur->info.nSize = 0;
   pCur->atLast = 0;
@@ -39863,9 +52252,8 @@ static int moveToRoot(BtCursor *pCur){
 
   if( pRoot->nCell==0 && !pRoot->leaf ){
     Pgno subpage;
-    assert( pRoot->pgno==1 );
+    if( pRoot->pgno!=1 ) return SQLITE_CORRUPT_BKPT;
     subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
-    assert( subpage>0 );
     pCur->eState = CURSOR_VALID;
     rc = moveToChild(pCur, subpage);
   }else{
@@ -39938,9 +52326,8 @@ SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
   rc = moveToRoot(pCur);
   if( rc==SQLITE_OK ){
     if( pCur->eState==CURSOR_INVALID ){
-      assert( pCur->apPage[pCur->iPage]->nCell==0 );
+      assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->nCell==0 );
       *pRes = 1;
-      rc = SQLITE_OK;
     }else{
       assert( pCur->apPage[pCur->iPage]->nCell>0 );
       *pRes = 0;
@@ -39959,16 +52346,31 @@ SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
  
   assert( cursorHoldsMutex(pCur) );
   assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+
+  /* If the cursor already points to the last entry, this is a no-op. */
+  if( CURSOR_VALID==pCur->eState && pCur->atLast ){
+#ifdef SQLITE_DEBUG
+    /* This block serves to assert() that the cursor really does point 
+    ** to the last entry in the b-tree. */
+    int ii;
+    for(ii=0; ii<pCur->iPage; ii++){
+      assert( pCur->aiIdx[ii]==pCur->apPage[ii]->nCell );
+    }
+    assert( pCur->aiIdx[pCur->iPage]==pCur->apPage[pCur->iPage]->nCell-1 );
+    assert( pCur->apPage[pCur->iPage]->leaf );
+#endif
+    return SQLITE_OK;
+  }
+
   rc = moveToRoot(pCur);
   if( rc==SQLITE_OK ){
     if( CURSOR_INVALID==pCur->eState ){
-      assert( pCur->apPage[pCur->iPage]->nCell==0 );
+      assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->nCell==0 );
       *pRes = 1;
     }else{
       assert( pCur->eState==CURSOR_VALID );
       *pRes = 0;
       rc = moveToRightmost(pCur);
-      getCellInfo(pCur);
       pCur->atLast = rc==SQLITE_OK ?1:0;
     }
   }
@@ -40014,6 +52416,8 @@ SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
 
   assert( cursorHoldsMutex(pCur) );
   assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert( pRes );
+  assert( (pIdxKey==0)==(pCur->pKeyInfo==0) );
 
   /* If the cursor is already positioned at the point we are trying
   ** to move to, then just return without doing any work */
@@ -40034,39 +52438,44 @@ SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
   if( rc ){
     return rc;
   }
-  assert( pCur->apPage[pCur->iPage] );
-  assert( pCur->apPage[pCur->iPage]->isInit );
+  assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage] );
+  assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->isInit );
+  assert( pCur->eState==CURSOR_INVALID || pCur->apPage[pCur->iPage]->nCell>0 );
   if( pCur->eState==CURSOR_INVALID ){
     *pRes = -1;
-    assert( pCur->apPage[pCur->iPage]->nCell==0 );
+    assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->nCell==0 );
     return SQLITE_OK;
   }
   assert( pCur->apPage[0]->intKey || pIdxKey );
   for(;;){
-    int lwr, upr;
+    int lwr, upr, idx;
     Pgno chldPg;
     MemPage *pPage = pCur->apPage[pCur->iPage];
-    int c = -1;  /* pRes return if table is empty must be -1 */
+    int c;
+
+    /* pPage->nCell must be greater than zero. If this is the root-page
+    ** the cursor would have been INVALID above and this for(;;) loop
+    ** not run. If this is not the root-page, then the moveToChild() routine
+    ** would have already detected db corruption. Similarly, pPage must
+    ** be the right kind (index or table) of b-tree page. Otherwise
+    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
+    assert( pPage->nCell>0 );
+    assert( pPage->intKey==(pIdxKey==0) );
     lwr = 0;
     upr = pPage->nCell-1;
-    if( (!pPage->intKey && pIdxKey==0) || upr<0 ){
-      rc = SQLITE_CORRUPT_BKPT;
-      goto moveto_finish;
-    }
     if( biasRight ){
-      pCur->aiIdx[pCur->iPage] = (u16)upr;
+      pCur->aiIdx[pCur->iPage] = (u16)(idx = upr);
     }else{
-      pCur->aiIdx[pCur->iPage] = (u16)((upr+lwr)/2);
+      pCur->aiIdx[pCur->iPage] = (u16)(idx = (upr+lwr)/2);
     }
     for(;;){
-      void *pCellKey;
-      i64 nCellKey;
-      int idx = pCur->aiIdx[pCur->iPage];
+      u8 *pCell;                          /* Pointer to current cell in pPage */
+
+      assert( idx==pCur->aiIdx[pCur->iPage] );
       pCur->info.nSize = 0;
-      pCur->validNKey = 1;
+      pCell = findCell(pPage, idx) + pPage->childPtrSize;
       if( pPage->intKey ){
-        u8 *pCell;
-        pCell = findCell(pPage, idx) + pPage->childPtrSize;
+        i64 nCellKey;
         if( pPage->hasData ){
           u32 dummy;
           pCell += getVarint32(pCell, dummy);
@@ -40080,29 +52489,60 @@ SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
           assert( nCellKey>intKey );
           c = +1;
         }
+        pCur->validNKey = 1;
+        pCur->info.nKey = nCellKey;
       }else{
-        int available;
-        pCellKey = (void *)fetchPayload(pCur, &available, 0);
-        nCellKey = pCur->info.nKey;
-        if( available>=nCellKey ){
-          c = sqlite3VdbeRecordCompare((int)nCellKey, pCellKey, pIdxKey);
+        /* The maximum supported page-size is 65536 bytes. This means that
+        ** the maximum number of record bytes stored on an index B-Tree
+        ** page is less than 16384 bytes and may be stored as a 2-byte
+        ** varint. This information is used to attempt to avoid parsing 
+        ** the entire cell by checking for the cases where the record is 
+        ** stored entirely within the b-tree page by inspecting the first 
+        ** 2 bytes of the cell.
+        */
+        int nCell = pCell[0];
+        if( nCell<=pPage->max1bytePayload
+         /* && (pCell+nCell)<pPage->aDataEnd */
+        ){
+          /* This branch runs if the record-size field of the cell is a
+          ** single byte varint and the record fits entirely on the main
+          ** b-tree page.  */
+          testcase( pCell+nCell+1==pPage->aDataEnd );
+          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
+        }else if( !(pCell[1] & 0x80) 
+          && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
+          /* && (pCell+nCell+2)<=pPage->aDataEnd */
+        ){
+          /* The record-size field is a 2 byte varint and the record 
+          ** fits entirely on the main b-tree page.  */
+          testcase( pCell+nCell+2==pPage->aDataEnd );
+          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
         }else{
-          pCellKey = sqlite3Malloc( (int)nCellKey );
+          /* The record flows over onto one or more overflow pages. In
+          ** this case the whole cell needs to be parsed, a buffer allocated
+          ** and accessPayload() used to retrieve the record into the
+          ** buffer before VdbeRecordCompare() can be called. */
+          void *pCellKey;
+          u8 * const pCellBody = pCell - pPage->childPtrSize;
+          btreeParseCellPtr(pPage, pCellBody, &pCur->info);
+          nCell = (int)pCur->info.nKey;
+          pCellKey = sqlite3Malloc( nCell );
           if( pCellKey==0 ){
             rc = SQLITE_NOMEM;
             goto moveto_finish;
           }
-          rc = sqlite3BtreeKey(pCur, 0, (int)nCellKey, (void*)pCellKey);
-          c = sqlite3VdbeRecordCompare((int)nCellKey, pCellKey, pIdxKey);
+          rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 0);
+          if( rc ){
+            sqlite3_free(pCellKey);
+            goto moveto_finish;
+          }
+          c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey);
           sqlite3_free(pCellKey);
-          if( rc ) goto moveto_finish;
         }
       }
       if( c==0 ){
-        pCur->info.nKey = nCellKey;
         if( pPage->intKey && !pPage->leaf ){
           lwr = idx;
-          upr = lwr - 1;
           break;
         }else{
           *pRes = 0;
@@ -40116,12 +52556,11 @@ SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
         upr = idx-1;
       }
       if( lwr>upr ){
-        pCur->info.nKey = nCellKey;
         break;
       }
-      pCur->aiIdx[pCur->iPage] = (u16)((lwr+upr)/2);
+      pCur->aiIdx[pCur->iPage] = (u16)(idx = (lwr+upr)/2);
     }
-    assert( lwr==upr+1 );
+    assert( lwr==upr+1 || (pPage->intKey && !pPage->leaf) );
     assert( pPage->isInit );
     if( pPage->leaf ){
       chldPg = 0;
@@ -40132,7 +52571,7 @@ SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
     }
     if( chldPg==0 ){
       assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
-      if( pRes ) *pRes = c;
+      *pRes = c;
       rc = SQLITE_OK;
       goto moveto_finish;
     }
@@ -40146,37 +52585,6 @@ moveto_finish:
   return rc;
 }
 
-/*
-** In this version of BtreeMoveto, pKey is a packed index record
-** such as is generated by the OP_MakeRecord opcode.  Unpack the
-** record and then call BtreeMovetoUnpacked() to do the work.
-*/
-SQLITE_PRIVATE int sqlite3BtreeMoveto(
-  BtCursor *pCur,     /* Cursor open on the btree to be searched */
-  const void *pKey,   /* Packed key if the btree is an index */
-  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
-  int bias,           /* Bias search to the high end */
-  int *pRes           /* Write search results here */
-){
-  int rc;                    /* Status code */
-  UnpackedRecord *pIdxKey;   /* Unpacked index key */
-  UnpackedRecord aSpace[16]; /* Temp space for pIdxKey - to avoid a malloc */
-
-  if( pKey ){
-    assert( nKey==(i64)(int)nKey );
-    pIdxKey = sqlite3VdbeRecordUnpack(pCur->pKeyInfo, (int)nKey, pKey,
-                                      aSpace, sizeof(aSpace));
-    if( pIdxKey==0 ) return SQLITE_NOMEM;
-  }else{
-    pIdxKey = 0;
-  }
-  rc = sqlite3BtreeMovetoUnpacked(pCur, pIdxKey, nKey, bias, pRes);
-  if( pKey ){
-    sqlite3VdbeDeleteUnpackedRecord(pIdxKey);
-  }
-  return rc;
-}
-
 
 /*
 ** Return TRUE if the cursor is not pointing at an entry of the table.
@@ -40193,14 +52601,6 @@ SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor *pCur){
   return (CURSOR_VALID!=pCur->eState);
 }
 
-/*
-** Return the database connection handle for a cursor.
-*/
-SQLITE_PRIVATE sqlite3 *sqlite3BtreeCursorDb(const BtCursor *pCur){
-  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
-  return pCur->pBtree->db;
-}
-
 /*
 ** Advance the cursor to the next entry in the database.  If
 ** successful then set *pRes=0.  If the cursor
@@ -40222,17 +52622,23 @@ SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
     *pRes = 1;
     return SQLITE_OK;
   }
-  if( pCur->skip>0 ){
-    pCur->skip = 0;
+  if( pCur->skipNext>0 ){
+    pCur->skipNext = 0;
     *pRes = 0;
     return SQLITE_OK;
   }
-  pCur->skip = 0;
+  pCur->skipNext = 0;
 
   pPage = pCur->apPage[pCur->iPage];
   idx = ++pCur->aiIdx[pCur->iPage];
   assert( pPage->isInit );
-  assert( idx<=pPage->nCell );
+
+  /* If the database file is corrupt, it is possible for the value of idx 
+  ** to be invalid here. This can only occur if a second cursor modifies
+  ** the page while cursor pCur is holding a reference to it. Which can
+  ** only happen if the database is corrupt in such a way as to link the
+  ** page into more than one b-tree structure. */
+  testcase( idx>pPage->nCell );
 
   pCur->info.nSize = 0;
   pCur->validNKey = 0;
@@ -40250,7 +52656,7 @@ SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
         pCur->eState = CURSOR_INVALID;
         return SQLITE_OK;
       }
-      sqlite3BtreeMoveToParent(pCur);
+      moveToParent(pCur);
       pPage = pCur->apPage[pCur->iPage];
     }while( pCur->aiIdx[pCur->iPage]>=pPage->nCell );
     *pRes = 0;
@@ -40290,12 +52696,12 @@ SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
     *pRes = 1;
     return SQLITE_OK;
   }
-  if( pCur->skip<0 ){
-    pCur->skip = 0;
+  if( pCur->skipNext<0 ){
+    pCur->skipNext = 0;
     *pRes = 0;
     return SQLITE_OK;
   }
-  pCur->skip = 0;
+  pCur->skipNext = 0;
 
   pPage = pCur->apPage[pCur->iPage];
   assert( pPage->isInit );
@@ -40313,7 +52719,7 @@ SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
         *pRes = 1;
         return SQLITE_OK;
       }
-      sqlite3BtreeMoveToParent(pCur);
+      moveToParent(pCur);
     }
     pCur->info.nSize = 0;
     pCur->validNKey = 0;
@@ -40360,14 +52766,20 @@ static int allocateBtreePage(
 ){
   MemPage *pPage1;
   int rc;
-  int n;     /* Number of pages on the freelist */
-  int k;     /* Number of leaves on the trunk of the freelist */
+  u32 n;     /* Number of pages on the freelist */
+  u32 k;     /* Number of leaves on the trunk of the freelist */
   MemPage *pTrunk = 0;
   MemPage *pPrevTrunk = 0;
+  Pgno mxPage;     /* Total size of the database file */
 
   assert( sqlite3_mutex_held(pBt->mutex) );
   pPage1 = pBt->pPage1;
+  mxPage = btreePagecount(pBt);
   n = get4byte(&pPage1->aData[36]);
+  testcase( n==mxPage-1 );
+  if( n>=mxPage ){
+    return SQLITE_CORRUPT_BKPT;
+  }
   if( n>0 ){
     /* There are pages on the freelist.  Reuse one of those pages. */
     Pgno iTrunk;
@@ -40378,7 +52790,7 @@ static int allocateBtreePage(
     ** the entire-list will be searched for that page.
     */
 #ifndef SQLITE_OMIT_AUTOVACUUM
-    if( exact && nearby<=pagerPagecount(pBt) ){
+    if( exact && nearby<=mxPage ){
       u8 eType;
       assert( nearby>0 );
       assert( pBt->autoVacuum );
@@ -40409,13 +52821,20 @@ static int allocateBtreePage(
       }else{
         iTrunk = get4byte(&pPage1->aData[32]);
       }
-      rc = sqlite3BtreeGetPage(pBt, iTrunk, &pTrunk, 0);
+      testcase( iTrunk==mxPage );
+      if( iTrunk>mxPage ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }else{
+        rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
+      }
       if( rc ){
         pTrunk = 0;
         goto end_allocate_page;
       }
+      assert( pTrunk!=0 );
+      assert( pTrunk->aData!=0 );
 
-      k = get4byte(&pTrunk->aData[4]);
+      k = get4byte(&pTrunk->aData[4]); /* # of leaves on this trunk page */
       if( k==0 && !searchList ){
         /* The trunk has no leaves and the list is not being searched. 
         ** So extract the trunk page itself and use it as the newly 
@@ -40430,7 +52849,7 @@ static int allocateBtreePage(
         *ppPage = pTrunk;
         pTrunk = 0;
         TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
-      }else if( k>pBt->usableSize/4 - 2 ){
+      }else if( k>(u32)(pBt->usableSize/4 - 2) ){
         /* Value of k is out of range.  Database corruption */
         rc = SQLITE_CORRUPT_BKPT;
         goto end_allocate_page;
@@ -40450,6 +52869,10 @@ static int allocateBtreePage(
           if( !pPrevTrunk ){
             memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
           }else{
+            rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
+            if( rc!=SQLITE_OK ){
+              goto end_allocate_page;
+            }
             memcpy(&pPrevTrunk->aData[0], &pTrunk->aData[0], 4);
           }
         }else{
@@ -40459,7 +52882,12 @@ static int allocateBtreePage(
           */
           MemPage *pNewTrunk;
           Pgno iNewTrunk = get4byte(&pTrunk->aData[8]);
-          rc = sqlite3BtreeGetPage(pBt, iNewTrunk, &pNewTrunk, 0);
+          if( iNewTrunk>mxPage ){ 
+            rc = SQLITE_CORRUPT_BKPT;
+            goto end_allocate_page;
+          }
+          testcase( iNewTrunk==mxPage );
+          rc = btreeGetPage(pBt, iNewTrunk, &pNewTrunk, 0);
           if( rc!=SQLITE_OK ){
             goto end_allocate_page;
           }
@@ -40486,23 +52914,18 @@ static int allocateBtreePage(
         pTrunk = 0;
         TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
 #endif
-      }else{
+      }else if( k>0 ){
         /* Extract a leaf from the trunk */
-        int closest;
+        u32 closest;
         Pgno iPage;
         unsigned char *aData = pTrunk->aData;
-        rc = sqlite3PagerWrite(pTrunk->pDbPage);
-        if( rc ){
-          goto end_allocate_page;
-        }
         if( nearby>0 ){
-          int i, dist;
+          u32 i;
+          int dist;
           closest = 0;
-          dist = get4byte(&aData[8]) - nearby;
-          if( dist<0 ) dist = -dist;
+          dist = sqlite3AbsInt32(get4byte(&aData[8]) - nearby);
           for(i=1; i<k; i++){
-            int d2 = get4byte(&aData[8+i*4]) - nearby;
-            if( d2<0 ) d2 = -d2;
+            int d2 = sqlite3AbsInt32(get4byte(&aData[8+i*4]) - nearby);
             if( d2<dist ){
               closest = i;
               dist = d2;
@@ -40513,26 +52936,27 @@ static int allocateBtreePage(
         }
 
         iPage = get4byte(&aData[8+closest*4]);
+        testcase( iPage==mxPage );
+        if( iPage>mxPage ){
+          rc = SQLITE_CORRUPT_BKPT;
+          goto end_allocate_page;
+        }
+        testcase( iPage==mxPage );
         if( !searchList || iPage==nearby ){
-          Pgno nPage;
+          int noContent;
           *pPgno = iPage;
-          nPage = pagerPagecount(pBt);
-          if( *pPgno>nPage ){
-            /* Free page off the end of the file */
-            rc = SQLITE_CORRUPT_BKPT;
-            goto end_allocate_page;
-          }
           TRACE(("ALLOCATE: %d was leaf %d of %d on trunk %d"
                  ": %d more free pages\n",
                  *pPgno, closest+1, k, pTrunk->pgno, n-1));
+          rc = sqlite3PagerWrite(pTrunk->pDbPage);
+          if( rc ) goto end_allocate_page;
           if( closest<k-1 ){
             memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
           }
           put4byte(&aData[4], k-1);
-          assert( sqlite3PagerIswriteable(pTrunk->pDbPage) );
-          rc = sqlite3BtreeGetPage(pBt, *pPgno, ppPage, 1);
+          noContent = !btreeGetHasContent(pBt, *pPgno);
+          rc = btreeGetPage(pBt, *pPgno, ppPage, noContent);
           if( rc==SQLITE_OK ){
-            sqlite3PagerDontRollback((*ppPage)->pDbPage);
             rc = sqlite3PagerWrite((*ppPage)->pDbPage);
             if( rc!=SQLITE_OK ){
               releasePage(*ppPage);
@@ -40547,24 +52971,35 @@ static int allocateBtreePage(
   }else{
     /* There are no pages on the freelist, so create a new page at the
     ** end of the file */
-    int nPage = pagerPagecount(pBt);
-    *pPgno = nPage + 1;
+    rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+    if( rc ) return rc;
+    pBt->nPage++;
+    if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ) pBt->nPage++;
 
 #ifndef SQLITE_OMIT_AUTOVACUUM
-    if( pBt->autoVacuum && PTRMAP_ISPAGE(pBt, *pPgno) ){
+    if( pBt->autoVacuum && PTRMAP_ISPAGE(pBt, pBt->nPage) ){
       /* If *pPgno refers to a pointer-map page, allocate two new pages
       ** at the end of the file instead of one. The first allocated page
       ** becomes a new pointer-map page, the second is used by the caller.
       */
-      TRACE(("ALLOCATE: %d from end of file (pointer-map page)\n", *pPgno));
-      assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
-      (*pPgno)++;
-      if( *pPgno==PENDING_BYTE_PAGE(pBt) ){ (*pPgno)++; }
+      MemPage *pPg = 0;
+      TRACE(("ALLOCATE: %d from end of file (pointer-map page)\n", pBt->nPage));
+      assert( pBt->nPage!=PENDING_BYTE_PAGE(pBt) );
+      rc = btreeGetPage(pBt, pBt->nPage, &pPg, 1);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pPg->pDbPage);
+        releasePage(pPg);
+      }
+      if( rc ) return rc;
+      pBt->nPage++;
+      if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ){ pBt->nPage++; }
     }
 #endif
+    put4byte(28 + (u8*)pBt->pPage1->aData, pBt->nPage);
+    *pPgno = pBt->nPage;
 
     assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
-    rc = sqlite3BtreeGetPage(pBt, *pPgno, ppPage, 0);
+    rc = btreeGetPage(pBt, *pPgno, ppPage, 1);
     if( rc ) return rc;
     rc = sqlite3PagerWrite((*ppPage)->pDbPage);
     if( rc!=SQLITE_OK ){
@@ -40584,65 +53019,95 @@ end_allocate_page:
       return SQLITE_CORRUPT_BKPT;
     }
     (*ppPage)->isInit = 0;
+  }else{
+    *ppPage = 0;
   }
+  assert( rc!=SQLITE_OK || sqlite3PagerIswriteable((*ppPage)->pDbPage) );
   return rc;
 }
 
 /*
-** Add a page of the database file to the freelist.
+** This function is used to add page iPage to the database file free-list. 
+** It is assumed that the page is not already a part of the free-list.
 **
-** sqlite3PagerUnref() is NOT called for pPage.
+** The value passed as the second argument to this function is optional.
+** If the caller happens to have a pointer to the MemPage object 
+** corresponding to page iPage handy, it may pass it as the second value. 
+** Otherwise, it may pass NULL.
+**
+** If a pointer to a MemPage object is passed as the second argument,
+** its reference count is not altered by this function.
 */
-static int freePage(MemPage *pPage){
-  BtShared *pBt = pPage->pBt;
-  MemPage *pPage1 = pBt->pPage1;
-  int rc, n, k;
+static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
+  MemPage *pTrunk = 0;                /* Free-list trunk page */
+  Pgno iTrunk = 0;                    /* Page number of free-list trunk page */ 
+  MemPage *pPage1 = pBt->pPage1;      /* Local reference to page 1 */
+  MemPage *pPage;                     /* Page being freed. May be NULL. */
+  int rc;                             /* Return Code */
+  int nFree;                          /* Initial number of pages on free-list */
 
-  /* Prepare the page for freeing */
-  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  assert( pPage->pgno>1 );
-  pPage->isInit = 0;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( iPage>1 );
+  assert( !pMemPage || pMemPage->pgno==iPage );
+
+  if( pMemPage ){
+    pPage = pMemPage;
+    sqlite3PagerRef(pPage->pDbPage);
+  }else{
+    pPage = btreePageLookup(pBt, iPage);
+  }
 
   /* Increment the free page count on pPage1 */
   rc = sqlite3PagerWrite(pPage1->pDbPage);
-  if( rc ) return rc;
-  n = get4byte(&pPage1->aData[36]);
-  put4byte(&pPage1->aData[36], n+1);
+  if( rc ) goto freepage_out;
+  nFree = get4byte(&pPage1->aData[36]);
+  put4byte(&pPage1->aData[36], nFree+1);
 
-#ifdef SQLITE_SECURE_DELETE
-  /* If the SQLITE_SECURE_DELETE compile-time option is enabled, then
-  ** always fully overwrite deleted information with zeros.
-  */
-  rc = sqlite3PagerWrite(pPage->pDbPage);
-  if( rc ) return rc;
-  memset(pPage->aData, 0, pPage->pBt->pageSize);
-#endif
+  if( pBt->btsFlags & BTS_SECURE_DELETE ){
+    /* If the secure_delete option is enabled, then
+    ** always fully overwrite deleted information with zeros.
+    */
+    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
+     ||            ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
+    ){
+      goto freepage_out;
+    }
+    memset(pPage->aData, 0, pPage->pBt->pageSize);
+  }
 
   /* If the database supports auto-vacuum, write an entry in the pointer-map
   ** to indicate that the page is free.
   */
   if( ISAUTOVACUUM ){
-    rc = ptrmapPut(pBt, pPage->pgno, PTRMAP_FREEPAGE, 0);
-    if( rc ) return rc;
+    ptrmapPut(pBt, iPage, PTRMAP_FREEPAGE, 0, &rc);
+    if( rc ) goto freepage_out;
   }
 
-  if( n==0 ){
-    /* This is the first free page */
-    rc = sqlite3PagerWrite(pPage->pDbPage);
-    if( rc ) return rc;
-    memset(pPage->aData, 0, 8);
-    put4byte(&pPage1->aData[32], pPage->pgno);
-    TRACE(("FREE-PAGE: %d first\n", pPage->pgno));
-  }else{
-    /* Other free pages already exist.  Retrive the first trunk page
-    ** of the freelist and find out how many leaves it has. */
-    MemPage *pTrunk;
-    rc = sqlite3BtreeGetPage(pBt, get4byte(&pPage1->aData[32]), &pTrunk, 0);
-    if( rc ) return rc;
-    k = get4byte(&pTrunk->aData[4]);
-    if( k>=pBt->usableSize/4 - 8 ){
-      /* The trunk is full.  Turn the page being freed into a new
-      ** trunk page with no leaves.
+  /* Now manipulate the actual database free-list structure. There are two
+  ** possibilities. If the free-list is currently empty, or if the first
+  ** trunk page in the free-list is full, then this page will become a
+  ** new free-list trunk page. Otherwise, it will become a leaf of the
+  ** first trunk page in the current free-list. This block tests if it
+  ** is possible to add the page as a new free-list leaf.
+  */
+  if( nFree!=0 ){
+    u32 nLeaf;                /* Initial number of leaf cells on trunk page */
+
+    iTrunk = get4byte(&pPage1->aData[32]);
+    rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
+    if( rc!=SQLITE_OK ){
+      goto freepage_out;
+    }
+
+    nLeaf = get4byte(&pTrunk->aData[4]);
+    assert( pBt->usableSize>32 );
+    if( nLeaf > (u32)pBt->usableSize/4 - 2 ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto freepage_out;
+    }
+    if( nLeaf < (u32)pBt->usableSize/4 - 8 ){
+      /* In this case there is room on the trunk page to insert the page
+      ** being freed as a new leaf.
       **
       ** Note that the trunk page is not really full until it contains
       ** usableSize/4 - 2 entries, not usableSize/4 - 8 entries as we have
@@ -40650,37 +53115,56 @@ static int freePage(MemPage *pPage){
       ** 3.6.0, databases with freelist trunk pages holding more than
       ** usableSize/4 - 8 entries will be reported as corrupt.  In order
       ** to maintain backwards compatibility with older versions of SQLite,
-      ** we will contain to restrict the number of entries to usableSize/4 - 8
+      ** we will continue to restrict the number of entries to usableSize/4 - 8
       ** for now.  At some point in the future (once everyone has upgraded
       ** to 3.6.0 or later) we should consider fixing the conditional above
       ** to read "usableSize/4-2" instead of "usableSize/4-8".
       */
-      rc = sqlite3PagerWrite(pPage->pDbPage);
-      if( rc==SQLITE_OK ){
-        put4byte(pPage->aData, pTrunk->pgno);
-        put4byte(&pPage->aData[4], 0);
-        put4byte(&pPage1->aData[32], pPage->pgno);
-        TRACE(("FREE-PAGE: %d new trunk page replacing %d\n",
-                pPage->pgno, pTrunk->pgno));
-      }
-    }else if( k<0 ){
-      rc = SQLITE_CORRUPT;
-    }else{
-      /* Add the newly freed page as a leaf on the current trunk */
       rc = sqlite3PagerWrite(pTrunk->pDbPage);
       if( rc==SQLITE_OK ){
-        put4byte(&pTrunk->aData[4], k+1);
-        put4byte(&pTrunk->aData[8+k*4], pPage->pgno);
-#ifndef SQLITE_SECURE_DELETE
-        rc = sqlite3PagerDontWrite(pPage->pDbPage);
-#endif
+        put4byte(&pTrunk->aData[4], nLeaf+1);
+        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
+        if( pPage && (pBt->btsFlags & BTS_SECURE_DELETE)==0 ){
+          sqlite3PagerDontWrite(pPage->pDbPage);
+        }
+        rc = btreeSetHasContent(pBt, iPage);
       }
       TRACE(("FREE-PAGE: %d leaf on trunk page %d\n",pPage->pgno,pTrunk->pgno));
+      goto freepage_out;
     }
-    releasePage(pTrunk);
   }
+
+  /* If control flows to this point, then it was not possible to add the
+  ** the page being freed as a leaf page of the first trunk in the free-list.
+  ** Possibly because the free-list is empty, or possibly because the 
+  ** first trunk in the free-list is full. Either way, the page being freed
+  ** will become the new first trunk page in the free-list.
+  */
+  if( pPage==0 && SQLITE_OK!=(rc = btreeGetPage(pBt, iPage, &pPage, 0)) ){
+    goto freepage_out;
+  }
+  rc = sqlite3PagerWrite(pPage->pDbPage);
+  if( rc!=SQLITE_OK ){
+    goto freepage_out;
+  }
+  put4byte(pPage->aData, iTrunk);
+  put4byte(&pPage->aData[4], 0);
+  put4byte(&pPage1->aData[32], iPage);
+  TRACE(("FREE-PAGE: %d new trunk page replacing %d\n", pPage->pgno, iTrunk));
+
+freepage_out:
+  if( pPage ){
+    pPage->isInit = 0;
+  }
+  releasePage(pPage);
+  releasePage(pTrunk);
   return rc;
 }
+static void freePage(MemPage *pPage, int *pRC){
+  if( (*pRC)==SQLITE_OK ){
+    *pRC = freePage2(pPage->pBt, pPage, pPage->pgno);
+  }
+}
 
 /*
 ** Free any overflow pages associated with the given Cell.
@@ -40691,28 +53175,58 @@ static int clearCell(MemPage *pPage, unsigned char *pCell){
   Pgno ovflPgno;
   int rc;
   int nOvfl;
-  int ovflPageSize;
+  u32 ovflPageSize;
 
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+  btreeParseCellPtr(pPage, pCell, &info);
   if( info.iOverflow==0 ){
     return SQLITE_OK;  /* No overflow pages. Return without doing anything */
   }
+  if( pCell+info.iOverflow+3 > pPage->aData+pPage->maskPage ){
+    return SQLITE_CORRUPT;  /* Cell extends past end of page */
+  }
   ovflPgno = get4byte(&pCell[info.iOverflow]);
+  assert( pBt->usableSize > 4 );
   ovflPageSize = pBt->usableSize - 4;
   nOvfl = (info.nPayload - info.nLocal + ovflPageSize - 1)/ovflPageSize;
   assert( ovflPgno==0 || nOvfl>0 );
   while( nOvfl-- ){
-    MemPage *pOvfl;
-    if( ovflPgno==0 || ovflPgno>pagerPagecount(pBt) ){
+    Pgno iNext = 0;
+    MemPage *pOvfl = 0;
+    if( ovflPgno<2 || ovflPgno>btreePagecount(pBt) ){
+      /* 0 is not a legal page number and page 1 cannot be an 
+      ** overflow page. Therefore if ovflPgno<2 or past the end of the 
+      ** file the database must be corrupt. */
       return SQLITE_CORRUPT_BKPT;
     }
+    if( nOvfl ){
+      rc = getOverflowPage(pBt, ovflPgno, &pOvfl, &iNext);
+      if( rc ) return rc;
+    }
 
-    rc = getOverflowPage(pBt, ovflPgno, &pOvfl, (nOvfl==0)?0:&ovflPgno);
-    if( rc ) return rc;
-    rc = freePage(pOvfl);
-    sqlite3PagerUnref(pOvfl->pDbPage);
+    if( ( pOvfl || ((pOvfl = btreePageLookup(pBt, ovflPgno))!=0) )
+     && sqlite3PagerPageRefcount(pOvfl->pDbPage)!=1
+    ){
+      /* There is no reason any cursor should have an outstanding reference 
+      ** to an overflow page belonging to a cell that is being deleted/updated.
+      ** So if there exists more than one reference to this page, then it 
+      ** must not really be an overflow page and the database must be corrupt. 
+      ** It is helpful to detect this before calling freePage2(), as 
+      ** freePage2() may zero the page contents if secure-delete mode is
+      ** enabled. If this 'overflow' page happens to be a page that the
+      ** caller is iterating through or using in some other way, this
+      ** can be problematic.
+      */
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = freePage2(pBt, pOvfl, ovflPgno);
+    }
+
+    if( pOvfl ){
+      sqlite3PagerUnref(pOvfl->pDbPage);
+    }
     if( rc ) return rc;
+    ovflPgno = iNext;
   }
   return SQLITE_OK;
 }
@@ -40768,7 +53282,7 @@ static int fillInCell(
     nData = nZero = 0;
   }
   nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
-  sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+  btreeParseCellPtr(pPage, pCell, &info);
   assert( info.nHeader==nHeader );
   assert( info.nKey==nKey );
   assert( info.nData==(u32)(nData+nZero) );
@@ -40780,7 +53294,9 @@ static int fillInCell(
     nSrc = nData;
     nData = 0;
   }else{ 
-    /* TBD:  Perhaps raise SQLITE_CORRUPT if nKey is larger than 31 bits? */
+    if( NEVER(nKey>0x7fffffff || pKey==0) ){
+      return SQLITE_CORRUPT_BKPT;
+    }
     nPayload += (int)nKey;
     pSrc = pKey;
     nSrc = (int)nKey;
@@ -40816,7 +53332,7 @@ static int fillInCell(
       */
       if( pBt->autoVacuum && rc==SQLITE_OK ){
         u8 eType = (pgnoPtrmap?PTRMAP_OVERFLOW2:PTRMAP_OVERFLOW1);
-        rc = ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap);
+        ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap, &rc);
         if( rc ){
           releasePage(pOvfl);
         }
@@ -40885,36 +53401,44 @@ static int fillInCell(
 **
 ** "sz" must be the number of bytes in the cell.
 */
-static int dropCell(MemPage *pPage, int idx, int sz){
-  int i;          /* Loop counter */
-  int pc;         /* Offset to cell content of cell being deleted */
+static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){
+  u32 pc;         /* Offset to cell content of cell being deleted */
   u8 *data;       /* pPage->aData */
   u8 *ptr;        /* Used to move bytes around within data[] */
+  u8 *endPtr;     /* End of loop */
   int rc;         /* The return code */
+  int hdr;        /* Beginning of the header.  0 most pages.  100 page 1 */
+
+  if( *pRC ) return;
 
   assert( idx>=0 && idx<pPage->nCell );
   assert( sz==cellSize(pPage, idx) );
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
   data = pPage->aData;
-  ptr = &data[pPage->cellOffset + 2*idx];
+  ptr = &pPage->aCellIdx[2*idx];
   pc = get2byte(ptr);
-  if( (pc<pPage->hdrOffset+6+(pPage->leaf?0:4))
-     || (pc+sz>pPage->pBt->usableSize) ){
-    return SQLITE_CORRUPT_BKPT;
+  hdr = pPage->hdrOffset;
+  testcase( pc==get2byte(&data[hdr+5]) );
+  testcase( pc+sz==pPage->pBt->usableSize );
+  if( pc < (u32)get2byte(&data[hdr+5]) || pc+sz > pPage->pBt->usableSize ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    return;
   }
   rc = freeSpace(pPage, pc, sz);
-  if( rc!=SQLITE_OK ){
-    return rc;
+  if( rc ){
+    *pRC = rc;
+    return;
   }
-  for(i=idx+1; i<pPage->nCell; i++, ptr+=2){
-    ptr[0] = ptr[2];
-    ptr[1] = ptr[3];
+  endPtr = &pPage->aCellIdx[2*pPage->nCell - 2];
+  assert( (SQLITE_PTR_TO_INT(ptr)&1)==0 );  /* ptr is always 2-byte aligned */
+  while( ptr<endPtr ){
+    *(u16*)ptr = *(u16*)&ptr[2];
+    ptr += 2;
   }
   pPage->nCell--;
-  put2byte(&data[pPage->hdrOffset+3], pPage->nCell);
+  put2byte(&data[hdr+3], pPage->nCell);
   pPage->nFree += 2;
-  return SQLITE_OK;
 }
 
 /*
@@ -40924,7 +53448,7 @@ static int dropCell(MemPage *pPage, int idx, int sz){
 ** If the cell content will fit on the page, then put it there.  If it
 ** will not fit, then make a copy of the cell content into pTemp if
 ** pTemp is not null.  Regardless of pTemp, allocate a new entry
-** in pPage->aOvfl[] and make it point to the cell content (either
+** in pPage->apOvfl[] and make it point to the cell content (either
 ** in pTemp or the original pCell) and also record its index. 
 ** Allocating a new entry in pPage->aCell[] implies that 
 ** pPage->nOverflow is incremented.
@@ -40934,92 +53458,92 @@ static int dropCell(MemPage *pPage, int idx, int sz){
 ** nSkip is non-zero, then pCell may not point to an invalid memory location 
 ** (but pCell+nSkip is always valid).
 */
-static int insertCell(
+static void insertCell(
   MemPage *pPage,   /* Page into which we are copying */
   int i,            /* New cell becomes the i-th cell of the page */
   u8 *pCell,        /* Content of the new cell */
   int sz,           /* Bytes of content in pCell */
   u8 *pTemp,        /* Temp storage space for pCell, if needed */
-  u8 nSkip          /* Do not write the first nSkip bytes of the cell */
+  Pgno iChild,      /* If non-zero, replace first 4 bytes with this value */
+  int *pRC          /* Read and write return code from here */
 ){
-  int idx;          /* Where to write new cell content in data[] */
+  int idx = 0;      /* Where to write new cell content in data[] */
   int j;            /* Loop counter */
-  int top;          /* First byte of content for any cell in data[] */
   int end;          /* First byte past the last cell pointer in data[] */
   int ins;          /* Index in data[] where new cell pointer is inserted */
-  int hdr;          /* Offset into data[] of the page header */
   int cellOffset;   /* Address of first cell pointer in data[] */
   u8 *data;         /* The content of the whole page */
   u8 *ptr;          /* Used for moving information around in data[] */
+  u8 *endPtr;       /* End of the loop */
+
+  int nSkip = (iChild ? 4 : 0);
+
+  if( *pRC ) return;
 
   assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
-  assert( pPage->nCell<=MX_CELL(pPage->pBt) && MX_CELL(pPage->pBt)<=5460 );
-  assert( pPage->nOverflow<=ArraySize(pPage->aOvfl) );
-  assert( sz==cellSizePtr(pPage, pCell) );
+  assert( pPage->nCell<=MX_CELL(pPage->pBt) && MX_CELL(pPage->pBt)<=10921 );
+  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );
+  assert( ArraySize(pPage->apOvfl)==ArraySize(pPage->aiOvfl) );
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  /* The cell should normally be sized correctly.  However, when moving a
+  ** malformed cell from a leaf page to an interior page, if the cell size
+  ** wanted to be less than 4 but got rounded up to 4 on the leaf, then size
+  ** might be less than 8 (leaf-size + pointer) on the interior node.  Hence
+  ** the term after the || in the following assert(). */
+  assert( sz==cellSizePtr(pPage, pCell) || (sz==8 && iChild>0) );
   if( pPage->nOverflow || sz+2>pPage->nFree ){
     if( pTemp ){
       memcpy(pTemp+nSkip, pCell+nSkip, sz-nSkip);
       pCell = pTemp;
     }
+    if( iChild ){
+      put4byte(pCell, iChild);
+    }
     j = pPage->nOverflow++;
-    assert( j<(int)(sizeof(pPage->aOvfl)/sizeof(pPage->aOvfl[0])) );
-    pPage->aOvfl[j].pCell = pCell;
-    pPage->aOvfl[j].idx = (u16)i;
-    pPage->nFree = 0;
+    assert( j<(int)(sizeof(pPage->apOvfl)/sizeof(pPage->apOvfl[0])) );
+    pPage->apOvfl[j] = pCell;
+    pPage->aiOvfl[j] = (u16)i;
   }else{
     int rc = sqlite3PagerWrite(pPage->pDbPage);
     if( rc!=SQLITE_OK ){
-      return rc;
+      *pRC = rc;
+      return;
     }
     assert( sqlite3PagerIswriteable(pPage->pDbPage) );
     data = pPage->aData;
-    hdr = pPage->hdrOffset;
-    top = get2byte(&data[hdr+5]);
     cellOffset = pPage->cellOffset;
-    end = cellOffset + 2*pPage->nCell + 2;
+    end = cellOffset + 2*pPage->nCell;
     ins = cellOffset + 2*i;
-    if( end > top - sz ){
-      rc = defragmentPage(pPage);
-      if( rc!=SQLITE_OK ){
-        return rc;
-      }
-      top = get2byte(&data[hdr+5]);
-      assert( end + sz <= top );
-    }
-    idx = allocateSpace(pPage, sz);
-    assert( idx>0 );
-    assert( end <= get2byte(&data[hdr+5]) );
-    if (idx+sz > pPage->pBt->usableSize) {
-      return SQLITE_CORRUPT_BKPT;
-    }
+    rc = allocateSpace(pPage, sz, &idx);
+    if( rc ){ *pRC = rc; return; }
+    /* The allocateSpace() routine guarantees the following two properties
+    ** if it returns success */
+    assert( idx >= end+2 );
+    assert( idx+sz <= (int)pPage->pBt->usableSize );
     pPage->nCell++;
-    pPage->nFree -= 2;
+    pPage->nFree -= (u16)(2 + sz);
     memcpy(&data[idx+nSkip], pCell+nSkip, sz-nSkip);
-    for(j=end-2, ptr=&data[j]; j>ins; j-=2, ptr-=2){
-      ptr[0] = ptr[-2];
-      ptr[1] = ptr[-1];
+    if( iChild ){
+      put4byte(&data[idx], iChild);
+    }
+    ptr = &data[end];
+    endPtr = &data[ins];
+    assert( (SQLITE_PTR_TO_INT(ptr)&1)==0 );  /* ptr is always 2-byte aligned */
+    while( ptr>endPtr ){
+      *(u16*)ptr = *(u16*)&ptr[-2];
+      ptr -= 2;
     }
     put2byte(&data[ins], idx);
-    put2byte(&data[hdr+3], pPage->nCell);
+    put2byte(&data[pPage->hdrOffset+3], pPage->nCell);
 #ifndef SQLITE_OMIT_AUTOVACUUM
     if( pPage->pBt->autoVacuum ){
       /* The cell may contain a pointer to an overflow page. If so, write
       ** the entry for the overflow page into the pointer map.
       */
-      CellInfo info;
-      sqlite3BtreeParseCellPtr(pPage, pCell, &info);
-      assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
-      if( (info.nData+(pPage->intKey?0:info.nKey))>info.nLocal ){
-        Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
-        rc = ptrmapPut(pPage->pBt, pgnoOvfl, PTRMAP_OVERFLOW1, pPage->pgno);
-        if( rc!=SQLITE_OK ) return rc;
-      }
+      ptrmapPutOvflPtr(pPage, pCell, pRC);
     }
 #endif
   }
-
-  return SQLITE_OK;
 }
 
 /*
@@ -41033,39 +53557,34 @@ static void assemblePage(
   u16 *aSize        /* Sizes of the cells */
 ){
   int i;            /* Loop counter */
-  int totalSize;    /* Total size of all cells */
-  int hdr;          /* Index of page header */
-  int cellptr;      /* Address of next cell pointer */
+  u8 *pCellptr;     /* Address of next cell pointer */
   int cellbody;     /* Address of next cell body */
-  u8 *data;         /* Data for the page */
+  u8 * const data = pPage->aData;             /* Pointer to data for pPage */
+  const int hdr = pPage->hdrOffset;           /* Offset of header on pPage */
+  const int nUsable = pPage->pBt->usableSize; /* Usable size of page */
 
   assert( pPage->nOverflow==0 );
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  assert( nCell>=0 && nCell<=MX_CELL(pPage->pBt) && MX_CELL(pPage->pBt)<=5460 );
-  totalSize = 0;
-  for(i=0; i<nCell; i++){
-    totalSize += aSize[i];
-  }
-  assert( totalSize+2*nCell<=pPage->nFree );
-  assert( pPage->nCell==0 );
+  assert( nCell>=0 && nCell<=(int)MX_CELL(pPage->pBt)
+            && (int)MX_CELL(pPage->pBt)<=10921);
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-  cellptr = pPage->cellOffset;
-  data = pPage->aData;
-  hdr = pPage->hdrOffset;
-  put2byte(&data[hdr+3], nCell);
-  if( nCell ){
-    cellbody = allocateSpace(pPage, totalSize);
-    assert( cellbody>0 );
-    assert( pPage->nFree >= 2*nCell );
-    pPage->nFree -= 2*nCell;
-    for(i=0; i<nCell; i++){
-      put2byte(&data[cellptr], cellbody);
-      memcpy(&data[cellbody], apCell[i], aSize[i]);
-      cellptr += 2;
-      cellbody += aSize[i];
-    }
-    assert( cellbody==pPage->pBt->usableSize );
+
+  /* Check that the page has just been zeroed by zeroPage() */
+  assert( pPage->nCell==0 );
+  assert( get2byteNotZero(&data[hdr+5])==nUsable );
+
+  pCellptr = &pPage->aCellIdx[nCell*2];
+  cellbody = nUsable;
+  for(i=nCell-1; i>=0; i--){
+    u16 sz = aSize[i];
+    pCellptr -= 2;
+    cellbody -= sz;
+    put2byte(pCellptr, cellbody);
+    memcpy(&data[cellbody], apCell[i], sz);
   }
+  put2byte(&data[hdr+3], nCell);
+  put2byte(&data[hdr+5], cellbody);
+  pPage->nFree -= (nCell*2 + nUsable - cellbody);
   pPage->nCell = (u16)nCell;
 }
 
@@ -41084,8 +53603,6 @@ static void assemblePage(
 #define NN 1             /* Number of neighbors on either side of pPage */
 #define NB (NN*2+1)      /* Total pages involved in the balance */
 
-/* Forward reference */
-static int balance(BtCursor*, int);
 
 #ifndef SQLITE_OMIT_QUICKBALANCE
 /*
@@ -41094,7 +53611,7 @@ static int balance(BtCursor*, int);
 ** tree, in other words, when the new entry will become the largest
 ** entry in the tree.
 **
-** Instead of trying balance the 3 right-most leaf pages, just add
+** Instead of trying to balance the 3 right-most leaf pages, just add
 ** a new page to the right-hand side and put the one new entry in
 ** that page.  This leaves the right side of the tree somewhat
 ** unbalanced.  But odds are that we will be inserting new entries
@@ -41104,257 +53621,371 @@ static int balance(BtCursor*, int);
 ** pPage is the leaf page which is the right-most page in the tree.
 ** pParent is its parent.  pPage must have a single overflow entry
 ** which is also the right-most entry on the page.
+**
+** The pSpace buffer is used to store a temporary copy of the divider
+** cell that will be inserted into pParent. Such a cell consists of a 4
+** byte page number followed by a variable length integer. In other
+** words, at most 13 bytes. Hence the pSpace buffer must be at
+** least 13 bytes in size.
 */
-static int balance_quick(BtCursor *pCur){
-  int rc;
-  MemPage *pNew = 0;
-  Pgno pgnoNew;
-  u8 *pCell;
-  u16 szCell;
-  CellInfo info;
-  MemPage *pPage = pCur->apPage[pCur->iPage];
-  MemPage *pParent = pCur->apPage[pCur->iPage-1];
-  BtShared *pBt = pPage->pBt;
-  int parentIdx = pParent->nCell;   /* pParent new divider cell index */
-  int parentSize;                   /* Size of new divider cell */
-  u8 parentCell[64];                /* Space for the new divider cell */
+static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
+  BtShared *const pBt = pPage->pBt;    /* B-Tree Database */
+  MemPage *pNew;                       /* Newly allocated page */
+  int rc;                              /* Return Code */
+  Pgno pgnoNew;                        /* Page number of pNew */
 
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  assert( pPage->nOverflow==1 );
 
-  /* Allocate a new page. Insert the overflow cell from pPage
-  ** into it. Then remove the overflow cell from pPage.
+  /* This error condition is now caught prior to reaching this function */
+  if( pPage->nCell<=0 ) return SQLITE_CORRUPT_BKPT;
+
+  /* Allocate a new page. This page will become the right-sibling of 
+  ** pPage. Make the parent page writable, so that the new divider cell
+  ** may be inserted. If both these operations are successful, proceed.
   */
   rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
+
   if( rc==SQLITE_OK ){
-    pCell = pPage->aOvfl[0].pCell;
-    szCell = cellSizePtr(pPage, pCell);
+
+    u8 *pOut = &pSpace[4];
+    u8 *pCell = pPage->apOvfl[0];
+    u16 szCell = cellSizePtr(pPage, pCell);
+    u8 *pStop;
+
     assert( sqlite3PagerIswriteable(pNew->pDbPage) );
-    zeroPage(pNew, pPage->aData[0]);
+    assert( pPage->aData[0]==(PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF) );
+    zeroPage(pNew, PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF);
     assemblePage(pNew, 1, &pCell, &szCell);
-    pPage->nOverflow = 0;
-  
-    /* pPage is currently the right-child of pParent. Change this
-    ** so that the right-child is the new page allocated above and
-    ** pPage is the next-to-right child. 
-    **
-    ** Ignore the return value of the call to fillInCell(). fillInCell()
-    ** may only return other than SQLITE_OK if it is required to allocate
-    ** one or more overflow pages. Since an internal table B-Tree cell 
-    ** may never spill over onto an overflow page (it is a maximum of 
-    ** 13 bytes in size), it is not neccessary to check the return code.
-    **
-    ** Similarly, the insertCell() function cannot fail if the page
-    ** being inserted into is already writable and the cell does not 
-    ** contain an overflow pointer. So ignore this return code too.
-    */
-    assert( pPage->nCell>0 );
-    pCell = findCell(pPage, pPage->nCell-1);
-    sqlite3BtreeParseCellPtr(pPage, pCell, &info);
-    fillInCell(pParent, parentCell, 0, info.nKey, 0, 0, 0, &parentSize);
-    assert( parentSize<64 );
-    assert( sqlite3PagerIswriteable(pParent->pDbPage) );
-    insertCell(pParent, parentIdx, parentCell, parentSize, 0, 4);
-    put4byte(findOverflowCell(pParent,parentIdx), pPage->pgno);
-    put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
-  
+
     /* If this is an auto-vacuum database, update the pointer map
     ** with entries for the new page, and any pointer from the 
-    ** cell on the page to an overflow page.
+    ** cell on the page to an overflow page. If either of these
+    ** operations fails, the return code is set, but the contents
+    ** of the parent page are still manipulated by thh code below.
+    ** That is Ok, at this point the parent page is guaranteed to
+    ** be marked as dirty. Returning an error code will cause a
+    ** rollback, undoing any changes made to the parent page.
     */
     if( ISAUTOVACUUM ){
-      rc = ptrmapPut(pBt, pgnoNew, PTRMAP_BTREE, pParent->pgno);
-      if( rc==SQLITE_OK ){
-        rc = ptrmapPutOvfl(pNew, 0);
+      ptrmapPut(pBt, pgnoNew, PTRMAP_BTREE, pParent->pgno, &rc);
+      if( szCell>pNew->minLocal ){
+        ptrmapPutOvflPtr(pNew, pCell, &rc);
       }
     }
+  
+    /* Create a divider cell to insert into pParent. The divider cell
+    ** consists of a 4-byte page number (the page number of pPage) and
+    ** a variable length key value (which must be the same value as the
+    ** largest key on pPage).
+    **
+    ** To find the largest key value on pPage, first find the right-most 
+    ** cell on pPage. The first two fields of this cell are the 
+    ** record-length (a variable length integer at most 32-bits in size)
+    ** and the key value (a variable length integer, may have any value).
+    ** The first of the while(...) loops below skips over the record-length
+    ** field. The second while(...) loop copies the key value from the
+    ** cell on pPage into the pSpace buffer.
+    */
+    pCell = findCell(pPage, pPage->nCell-1);
+    pStop = &pCell[9];
+    while( (*(pCell++)&0x80) && pCell<pStop );
+    pStop = &pCell[9];
+    while( ((*(pOut++) = *(pCell++))&0x80) && pCell<pStop );
 
+    /* Insert the new divider cell into pParent. */
+    insertCell(pParent, pParent->nCell, pSpace, (int)(pOut-pSpace),
+               0, pPage->pgno, &rc);
+
+    /* Set the right-child pointer of pParent to point to the new page. */
+    put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
+  
     /* Release the reference to the new page. */
     releasePage(pNew);
   }
 
-  /* At this point the pPage->nFree variable is not set correctly with
-  ** respect to the content of the page (because it was set to 0 by 
-  ** insertCell). So call sqlite3BtreeInitPage() to make sure it is
-  ** correct.
-  **
-  ** This has to be done even if an error will be returned. Normally, if
-  ** an error occurs during tree balancing, the contents of MemPage are
-  ** not important, as they will be recalculated when the page is rolled
-  ** back. But here, in balance_quick(), it is possible that pPage has 
-  ** not yet been marked dirty or written into the journal file. Therefore
-  ** it will not be rolled back and so it is important to make sure that
-  ** the page data and contents of MemPage are consistent.
-  */
-  pPage->isInit = 0;
-  sqlite3BtreeInitPage(pPage);
-  assert( pPage->nOverflow==0 );
-
-  /* If everything else succeeded, balance the parent page, in 
-  ** case the divider cell inserted caused it to become overfull.
-  */
-  if( rc==SQLITE_OK ){
-    releasePage(pPage);
-    pCur->iPage--;
-    rc = balance(pCur, 0);
-  }
   return rc;
 }
 #endif /* SQLITE_OMIT_QUICKBALANCE */
 
+#if 0
 /*
-** This routine redistributes Cells on pPage and up to NN*2 siblings
-** of pPage so that all pages have about the same amount of free space.
-** Usually NN siblings on either side of pPage is used in the balancing,
-** though more siblings might come from one side if pPage is the first
-** or last child of its parent.  If pPage has fewer than 2*NN siblings
-** (something which can only happen if pPage is the root page or a 
-** child of root) then all available siblings participate in the balancing.
+** This function does not contribute anything to the operation of SQLite.
+** it is sometimes activated temporarily while debugging code responsible 
+** for setting pointer-map entries.
+*/
+static int ptrmapCheckPages(MemPage **apPage, int nPage){
+  int i, j;
+  for(i=0; i<nPage; i++){
+    Pgno n;
+    u8 e;
+    MemPage *pPage = apPage[i];
+    BtShared *pBt = pPage->pBt;
+    assert( pPage->isInit );
+
+    for(j=0; j<pPage->nCell; j++){
+      CellInfo info;
+      u8 *z;
+     
+      z = findCell(pPage, j);
+      btreeParseCellPtr(pPage, z, &info);
+      if( info.iOverflow ){
+        Pgno ovfl = get4byte(&z[info.iOverflow]);
+        ptrmapGet(pBt, ovfl, &e, &n);
+        assert( n==pPage->pgno && e==PTRMAP_OVERFLOW1 );
+      }
+      if( !pPage->leaf ){
+        Pgno child = get4byte(z);
+        ptrmapGet(pBt, child, &e, &n);
+        assert( n==pPage->pgno && e==PTRMAP_BTREE );
+      }
+    }
+    if( !pPage->leaf ){
+      Pgno child = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+      ptrmapGet(pBt, child, &e, &n);
+      assert( n==pPage->pgno && e==PTRMAP_BTREE );
+    }
+  }
+  return 1;
+}
+#endif
+
+/*
+** This function is used to copy the contents of the b-tree node stored 
+** on page pFrom to page pTo. If page pFrom was not a leaf page, then
+** the pointer-map entries for each child page are updated so that the
+** parent page stored in the pointer map is page pTo. If pFrom contained
+** any cells with overflow page pointers, then the corresponding pointer
+** map entries are also updated so that the parent page is page pTo.
 **
-** The number of siblings of pPage might be increased or decreased by one or
-** two in an effort to keep pages nearly full but not over full. The root page
-** is special and is allowed to be nearly empty. If pPage is 
-** the root page, then the depth of the tree might be increased
-** or decreased by one, as necessary, to keep the root page from being
-** overfull or completely empty.
+** If pFrom is currently carrying any overflow cells (entries in the
+** MemPage.apOvfl[] array), they are not copied to pTo. 
 **
-** Note that when this routine is called, some of the Cells on pPage
-** might not actually be stored in pPage->aData[].  This can happen
-** if the page is overfull.  Part of the job of this routine is to
-** make sure all Cells for pPage once again fit in pPage->aData[].
+** Before returning, page pTo is reinitialized using btreeInitPage().
 **
-** In the course of balancing the siblings of pPage, the parent of pPage
-** might become overfull or underfull.  If that happens, then this routine
-** is called recursively on the parent.
+** The performance of this function is not critical. It is only used by 
+** the balance_shallower() and balance_deeper() procedures, neither of
+** which are called often under normal circumstances.
+*/
+static void copyNodeContent(MemPage *pFrom, MemPage *pTo, int *pRC){
+  if( (*pRC)==SQLITE_OK ){
+    BtShared * const pBt = pFrom->pBt;
+    u8 * const aFrom = pFrom->aData;
+    u8 * const aTo = pTo->aData;
+    int const iFromHdr = pFrom->hdrOffset;
+    int const iToHdr = ((pTo->pgno==1) ? 100 : 0);
+    int rc;
+    int iData;
+  
+  
+    assert( pFrom->isInit );
+    assert( pFrom->nFree>=iToHdr );
+    assert( get2byte(&aFrom[iFromHdr+5]) <= (int)pBt->usableSize );
+  
+    /* Copy the b-tree node content from page pFrom to page pTo. */
+    iData = get2byte(&aFrom[iFromHdr+5]);
+    memcpy(&aTo[iData], &aFrom[iData], pBt->usableSize-iData);
+    memcpy(&aTo[iToHdr], &aFrom[iFromHdr], pFrom->cellOffset + 2*pFrom->nCell);
+  
+    /* Reinitialize page pTo so that the contents of the MemPage structure
+    ** match the new data. The initialization of pTo can actually fail under
+    ** fairly obscure circumstances, even though it is a copy of initialized 
+    ** page pFrom.
+    */
+    pTo->isInit = 0;
+    rc = btreeInitPage(pTo);
+    if( rc!=SQLITE_OK ){
+      *pRC = rc;
+      return;
+    }
+  
+    /* If this is an auto-vacuum database, update the pointer-map entries
+    ** for any b-tree or overflow pages that pTo now contains the pointers to.
+    */
+    if( ISAUTOVACUUM ){
+      *pRC = setChildPtrmaps(pTo);
+    }
+  }
+}
+
+/*
+** This routine redistributes cells on the iParentIdx'th child of pParent
+** (hereafter "the page") and up to 2 siblings so that all pages have about the
+** same amount of free space. Usually a single sibling on either side of the
+** page are used in the balancing, though both siblings might come from one
+** side if the page is the first or last child of its parent. If the page 
+** has fewer than 2 siblings (something which can only happen if the page
+** is a root page or a child of a root page) then all available siblings
+** participate in the balancing.
+**
+** The number of siblings of the page might be increased or decreased by 
+** one or two in an effort to keep pages nearly full but not over full. 
+**
+** Note that when this routine is called, some of the cells on the page
+** might not actually be stored in MemPage.aData[]. This can happen
+** if the page is overfull. This routine ensures that all cells allocated
+** to the page and its siblings fit into MemPage.aData[] before returning.
+**
+** In the course of balancing the page and its siblings, cells may be
+** inserted into or removed from the parent page (pParent). Doing so
+** may cause the parent page to become overfull or underfull. If this
+** happens, it is the responsibility of the caller to invoke the correct
+** balancing routine to fix this problem (see the balance() routine). 
 **
 ** If this routine fails for any reason, it might leave the database
-** in a corrupted state.  So if this routine fails, the database should
+** in a corrupted state. So if this routine fails, the database should
 ** be rolled back.
+**
+** The third argument to this function, aOvflSpace, is a pointer to a
+** buffer big enough to hold one page. If while inserting cells into the parent
+** page (pParent) the parent page becomes overfull, this buffer is
+** used to store the parent's overflow cells. Because this function inserts
+** a maximum of four divider cells into the parent page, and the maximum
+** size of a cell stored within an internal node is always less than 1/4
+** of the page-size, the aOvflSpace[] buffer is guaranteed to be large
+** enough for all overflow cells.
+**
+** If aOvflSpace is set to a null pointer, this function returns 
+** SQLITE_NOMEM.
 */
-static int balance_nonroot(BtCursor *pCur){
-  MemPage *pPage;              /* The over or underfull page to balance */
-  MemPage *pParent;            /* The parent of pPage */
+#if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_M_ARM)
+#pragma optimize("", off)
+#endif
+static int balance_nonroot(
+  MemPage *pParent,               /* Parent page of siblings being balanced */
+  int iParentIdx,                 /* Index of "the page" in pParent */
+  u8 *aOvflSpace,                 /* page-size bytes of space for parent ovfl */
+  int isRoot,                     /* True if pParent is a root-page */
+  int bBulk                       /* True if this call is part of a bulk load */
+){
   BtShared *pBt;               /* The whole database */
   int nCell = 0;               /* Number of cells in apCell[] */
   int nMaxCells = 0;           /* Allocated size of apCell, szCell, aFrom. */
-  int nOld = 0;                /* Number of pages in apOld[] */
   int nNew = 0;                /* Number of pages in apNew[] */
-  int nDiv;                    /* Number of cells in apDiv[] */
+  int nOld;                    /* Number of pages in apOld[] */
   int i, j, k;                 /* Loop counters */
-  int idx;                     /* Index of pPage in pParent->aCell[] */
   int nxDiv;                   /* Next divider slot in pParent->aCell[] */
-  int rc;                      /* The return code */
-  int leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
+  int rc = SQLITE_OK;          /* The return code */
+  u16 leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
   int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
   int usableSpace;             /* Bytes in pPage beyond the header */
   int pageFlags;               /* Value of pPage->aData[0] */
   int subtotal;                /* Subtotal of bytes in cells on one page */
   int iSpace1 = 0;             /* First unused byte of aSpace1[] */
-  int iSpace2 = 0;             /* First unused byte of aSpace2[] */
+  int iOvflSpace = 0;          /* First unused byte of aOvflSpace[] */
   int szScratch;               /* Size of scratch memory requested */
   MemPage *apOld[NB];          /* pPage and up to two siblings */
-  Pgno pgnoOld[NB];            /* Page numbers for each page in apOld[] */
   MemPage *apCopy[NB];         /* Private copies of apOld[] pages */
   MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
-  Pgno pgnoNew[NB+2];          /* Page numbers for each page in apNew[] */
-  u8 *apDiv[NB];               /* Divider cells in pParent */
+  u8 *pRight;                  /* Location in parent of right-sibling pointer */
+  u8 *apDiv[NB-1];             /* Divider cells in pParent */
   int cntNew[NB+2];            /* Index in aCell[] of cell after i-th page */
   int szNew[NB+2];             /* Combined size of cells place on i-th page */
   u8 **apCell = 0;             /* All cells begin balanced */
   u16 *szCell;                 /* Local size of all cells in apCell[] */
-  u8 *aCopy[NB];         /* Space for holding data of apCopy[] */
-  u8 *aSpace1;           /* Space for copies of dividers cells before balance */
-  u8 *aSpace2 = 0;       /* Space for overflow dividers cells after balance */
-  u8 *aFrom = 0;
+  u8 *aSpace1;                 /* Space for copies of dividers cells */
+  Pgno pgno;                   /* Temp var to store a page number in */
 
-  pPage = pCur->apPage[pCur->iPage];
-  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  VVA_ONLY( pCur->pagesShuffled = 1 );
-
-  /* 
-  ** Find the parent page.
-  */
-  assert( pCur->iPage>0 );
-  assert( pPage->isInit );
-  assert( sqlite3PagerIswriteable(pPage->pDbPage) || pPage->nOverflow==1 );
-  pBt = pPage->pBt;
-  pParent = pCur->apPage[pCur->iPage-1];
-  assert( pParent );
-  if( SQLITE_OK!=(rc = sqlite3PagerWrite(pParent->pDbPage)) ){
-    goto balance_cleanup;
-  }
+  pBt = pParent->pBt;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
 
+#if 0
   TRACE(("BALANCE: begin page %d child of %d\n", pPage->pgno, pParent->pgno));
-
-#ifndef SQLITE_OMIT_QUICKBALANCE
-  /*
-  ** A special case:  If a new entry has just been inserted into a
-  ** table (that is, a btree with integer keys and all data at the leaves)
-  ** and the new entry is the right-most entry in the tree (it has the
-  ** largest key) then use the special balance_quick() routine for
-  ** balancing.  balance_quick() is much faster and results in a tighter
-  ** packing of data in the common case.
-  */
-  if( pPage->leaf &&
-      pPage->intKey &&
-      pPage->nOverflow==1 &&
-      pPage->aOvfl[0].idx==pPage->nCell &&
-      pParent->pgno!=1 &&
-      get4byte(&pParent->aData[pParent->hdrOffset+8])==pPage->pgno
-  ){
-    assert( pPage->intKey );
-    /*
-    ** TODO: Check the siblings to the left of pPage. It may be that
-    ** they are not full and no new page is required.
-    */
-    return balance_quick(pCur);
-  }
 #endif
 
-  if( SQLITE_OK!=(rc = sqlite3PagerWrite(pPage->pDbPage)) ){
-    goto balance_cleanup;
+  /* At this point pParent may have at most one overflow cell. And if
+  ** this overflow cell is present, it must be the cell with 
+  ** index iParentIdx. This scenario comes about when this function
+  ** is called (indirectly) from sqlite3BtreeDelete().
+  */
+  assert( pParent->nOverflow==0 || pParent->nOverflow==1 );
+  assert( pParent->nOverflow==0 || pParent->aiOvfl[0]==iParentIdx );
+
+  if( !aOvflSpace ){
+    return SQLITE_NOMEM;
   }
 
-  /*
-  ** Find the cell in the parent page whose left child points back
-  ** to pPage.  The "idx" variable is the index of that cell.  If pPage
-  ** is the rightmost child of pParent then set idx to pParent->nCell 
+  /* Find the sibling pages to balance. Also locate the cells in pParent 
+  ** that divide the siblings. An attempt is made to find NN siblings on 
+  ** either side of pPage. More siblings are taken from one side, however, 
+  ** if there are fewer than NN siblings on the other side. If pParent
+  ** has NB or fewer children then all children of pParent are taken.  
+  **
+  ** This loop also drops the divider cells from the parent page. This
+  ** way, the remainder of the function does not have to deal with any
+  ** overflow cells in the parent page, since if any existed they will
+  ** have already been removed.
   */
-  idx = pCur->aiIdx[pCur->iPage-1];
-  assertParentIndex(pParent, idx, pPage->pgno);
-
-  /*
-  ** Find sibling pages to pPage and the cells in pParent that divide
-  ** the siblings.  An attempt is made to find NN siblings on either
-  ** side of pPage.  More siblings are taken from one side, however, if
-  ** pPage there are fewer than NN siblings on the other side.  If pParent
-  ** has NB or fewer children then all children of pParent are taken.
-  */
-  nxDiv = idx - NN;
-  if( nxDiv + NB > pParent->nCell ){
-    nxDiv = pParent->nCell - NB + 1;
-  }
-  if( nxDiv<0 ){
+  i = pParent->nOverflow + pParent->nCell;
+  if( i<2 ){
     nxDiv = 0;
-  }
-  nDiv = 0;
-  for(i=0, k=nxDiv; i<NB; i++, k++){
-    if( k<pParent->nCell ){
-      apDiv[i] = findCell(pParent, k);
-      nDiv++;
-      assert( !pParent->leaf );
-      pgnoOld[i] = get4byte(apDiv[i]);
-    }else if( k==pParent->nCell ){
-      pgnoOld[i] = get4byte(&pParent->aData[pParent->hdrOffset+8]);
+  }else{
+    assert( bBulk==0 || bBulk==1 );
+    if( iParentIdx==0 ){                 
+      nxDiv = 0;
+    }else if( iParentIdx==i ){
+      nxDiv = i-2+bBulk;
     }else{
-      break;
+      assert( bBulk==0 );
+      nxDiv = iParentIdx-1;
+    }
+    i = 2-bBulk;
+  }
+  nOld = i+1;
+  if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
+    pRight = &pParent->aData[pParent->hdrOffset+8];
+  }else{
+    pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
+  }
+  pgno = get4byte(pRight);
+  while( 1 ){
+    rc = getAndInitPage(pBt, pgno, &apOld[i]);
+    if( rc ){
+      memset(apOld, 0, (i+1)*sizeof(MemPage*));
+      goto balance_cleanup;
     }
-    rc = getAndInitPage(pBt, pgnoOld[i], &apOld[i]);
-    if( rc ) goto balance_cleanup;
-    /* apOld[i]->idxParent = k; */
-    apCopy[i] = 0;
-    assert( i==nOld );
-    nOld++;
     nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
+    if( (i--)==0 ) break;
+
+    if( i+nxDiv==pParent->aiOvfl[0] && pParent->nOverflow ){
+      apDiv[i] = pParent->apOvfl[0];
+      pgno = get4byte(apDiv[i]);
+      szNew[i] = cellSizePtr(pParent, apDiv[i]);
+      pParent->nOverflow = 0;
+    }else{
+      apDiv[i] = findCell(pParent, i+nxDiv-pParent->nOverflow);
+      pgno = get4byte(apDiv[i]);
+      szNew[i] = cellSizePtr(pParent, apDiv[i]);
+
+      /* Drop the cell from the parent page. apDiv[i] still points to
+      ** the cell within the parent, even though it has been dropped.
+      ** This is safe because dropping a cell only overwrites the first
+      ** four bytes of it, and this function does not need the first
+      ** four bytes of the divider cell. So the pointer is safe to use
+      ** later on.  
+      **
+      ** But not if we are in secure-delete mode. In secure-delete mode,
+      ** the dropCell() routine will overwrite the entire cell with zeroes.
+      ** In this case, temporarily copy the cell into the aOvflSpace[]
+      ** buffer. It will be copied out again as soon as the aSpace[] buffer
+      ** is allocated.  */
+      if( pBt->btsFlags & BTS_SECURE_DELETE ){
+        int iOff;
+
+        iOff = SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent->aData);
+        if( (iOff+szNew[i])>(int)pBt->usableSize ){
+          rc = SQLITE_CORRUPT_BKPT;
+          memset(apOld, 0, (i+1)*sizeof(MemPage*));
+          goto balance_cleanup;
+        }else{
+          memcpy(&aOvflSpace[iOff], apDiv[i], szNew[i]);
+          apDiv[i] = &aOvflSpace[apDiv[i]-pParent->aData];
+        }
+      }
+      dropCell(pParent, i+nxDiv-pParent->nOverflow, szNew[i], &rc);
+    }
   }
 
   /* Make nMaxCells a multiple of 4 in order to preserve 8-byte
@@ -41364,52 +53995,25 @@ static int balance_nonroot(BtCursor *pCur){
   /*
   ** Allocate space for memory structures
   */
+  k = pBt->pageSize + ROUND8(sizeof(MemPage));
   szScratch =
        nMaxCells*sizeof(u8*)                       /* apCell */
      + nMaxCells*sizeof(u16)                       /* szCell */
-     + (ROUND8(sizeof(MemPage))+pBt->pageSize)*NB  /* aCopy */
      + pBt->pageSize                               /* aSpace1 */
-     + (ISAUTOVACUUM ? nMaxCells : 0);             /* aFrom */
+     + k*nOld;                                     /* Page copies (apCopy) */
   apCell = sqlite3ScratchMalloc( szScratch ); 
   if( apCell==0 ){
     rc = SQLITE_NOMEM;
     goto balance_cleanup;
   }
   szCell = (u16*)&apCell[nMaxCells];
-  aCopy[0] = (u8*)&szCell[nMaxCells];
-  assert( ((aCopy[0] - (u8*)0) & 7)==0 ); /* 8-byte alignment required */
-  for(i=1; i<NB; i++){
-    aCopy[i] = &aCopy[i-1][pBt->pageSize+ROUND8(sizeof(MemPage))];
-    assert( ((aCopy[i] - (u8*)0) & 7)==0 ); /* 8-byte alignment required */
-  }
-  aSpace1 = &aCopy[NB-1][pBt->pageSize+ROUND8(sizeof(MemPage))];
-  assert( ((aSpace1 - (u8*)0) & 7)==0 ); /* 8-byte alignment required */
-  if( ISAUTOVACUUM ){
-    aFrom = &aSpace1[pBt->pageSize];
-  }
-  aSpace2 = sqlite3PageMalloc(pBt->pageSize);
-  if( aSpace2==0 ){
-    rc = SQLITE_NOMEM;
-    goto balance_cleanup;
-  }
-  
-  /*
-  ** Make copies of the content of pPage and its siblings into aOld[].
-  ** The rest of this function will use data from the copies rather
-  ** that the original pages since the original pages will be in the
-  ** process of being overwritten.
-  */
-  for(i=0; i<nOld; i++){
-    MemPage *p = apCopy[i] = (MemPage*)aCopy[i];
-    memcpy(p, apOld[i], sizeof(MemPage));
-    p->aData = (void*)&p[1];
-    memcpy(p->aData, apOld[i]->aData, pBt->pageSize);
-  }
+  aSpace1 = (u8*)&szCell[nMaxCells];
+  assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );
 
   /*
   ** Load pointers to all cells on sibling pages and the divider cells
   ** into the local apCell[] array.  Make copies of the divider cells
-  ** into space obtained form aSpace1[] and remove the the divider Cells
+  ** into space obtained from aSpace1[] and remove the divider cells
   ** from pParent.
   **
   ** If the siblings are on leaf pages, then the child pointers of the
@@ -41422,69 +54026,67 @@ static int balance_nonroot(BtCursor *pCur){
   ** leafCorrection:  4 if pPage is a leaf.  0 if pPage is not a leaf.
   **       leafData:  1 if pPage holds key+data and pParent holds only keys.
   */
-  nCell = 0;
-  leafCorrection = pPage->leaf*4;
-  leafData = pPage->hasData;
+  leafCorrection = apOld[0]->leaf*4;
+  leafData = apOld[0]->hasData;
   for(i=0; i<nOld; i++){
-    MemPage *pOld = apCopy[i];
-    int limit = pOld->nCell+pOld->nOverflow;
-    for(j=0; j<limit; j++){
+    int limit;
+    
+    /* Before doing anything else, take a copy of the i'th original sibling
+    ** The rest of this function will use data from the copies rather
+    ** that the original pages since the original pages will be in the
+    ** process of being overwritten.  */
+    MemPage *pOld = apCopy[i] = (MemPage*)&aSpace1[pBt->pageSize + k*i];
+    memcpy(pOld, apOld[i], sizeof(MemPage));
+    pOld->aData = (void*)&pOld[1];
+    memcpy(pOld->aData, apOld[i]->aData, pBt->pageSize);
+
+    limit = pOld->nCell+pOld->nOverflow;
+    if( pOld->nOverflow>0 ){
+      for(j=0; j<limit; j++){
+        assert( nCell<nMaxCells );
+        apCell[nCell] = findOverflowCell(pOld, j);
+        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
+        nCell++;
+      }
+    }else{
+      u8 *aData = pOld->aData;
+      u16 maskPage = pOld->maskPage;
+      u16 cellOffset = pOld->cellOffset;
+      for(j=0; j<limit; j++){
+        assert( nCell<nMaxCells );
+        apCell[nCell] = findCellv2(aData, maskPage, cellOffset, j);
+        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
+        nCell++;
+      }
+    }       
+    if( i<nOld-1 && !leafData){
+      u16 sz = (u16)szNew[i];
+      u8 *pTemp;
       assert( nCell<nMaxCells );
-      apCell[nCell] = findOverflowCell(pOld, j);
-      szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
-      if( ISAUTOVACUUM ){
-        int a;
-        aFrom[nCell] = (u8)i;   assert( i>=0 && i<6 );
-        for(a=0; a<pOld->nOverflow; a++){
-          if( pOld->aOvfl[a].pCell==apCell[nCell] ){
-            aFrom[nCell] = 0xFF;
-            break;
-          }
+      szCell[nCell] = sz;
+      pTemp = &aSpace1[iSpace1];
+      iSpace1 += sz;
+      assert( sz<=pBt->maxLocal+23 );
+      assert( iSpace1 <= (int)pBt->pageSize );
+      memcpy(pTemp, apDiv[i], sz);
+      apCell[nCell] = pTemp+leafCorrection;
+      assert( leafCorrection==0 || leafCorrection==4 );
+      szCell[nCell] = szCell[nCell] - leafCorrection;
+      if( !pOld->leaf ){
+        assert( leafCorrection==0 );
+        assert( pOld->hdrOffset==0 );
+        /* The right pointer of the child page pOld becomes the left
+        ** pointer of the divider cell */
+        memcpy(apCell[nCell], &pOld->aData[8], 4);
+      }else{
+        assert( leafCorrection==4 );
+        if( szCell[nCell]<4 ){
+          /* Do not allow any cells smaller than 4 bytes. */
+          szCell[nCell] = 4;
         }
       }
       nCell++;
     }
-    if( i<nOld-1 ){
-      u16 sz = cellSizePtr(pParent, apDiv[i]);
-      if( leafData ){
-        /* With the LEAFDATA flag, pParent cells hold only INTKEYs that
-        ** are duplicates of keys on the child pages.  We need to remove
-        ** the divider cells from pParent, but the dividers cells are not
-        ** added to apCell[] because they are duplicates of child cells.
-        */
-        dropCell(pParent, nxDiv, sz);
-      }else{
-        u8 *pTemp;
-        assert( nCell<nMaxCells );
-        szCell[nCell] = sz;
-        pTemp = &aSpace1[iSpace1];
-        iSpace1 += sz;
-        assert( sz<=pBt->pageSize/4 );
-        assert( iSpace1<=pBt->pageSize );
-        memcpy(pTemp, apDiv[i], sz);
-        apCell[nCell] = pTemp+leafCorrection;
-        if( ISAUTOVACUUM ){
-          aFrom[nCell] = 0xFF;
-        }
-        dropCell(pParent, nxDiv, sz);
-        assert( leafCorrection==0 || leafCorrection==4 );
-        szCell[nCell] -= (u16)leafCorrection;
-        assert( get4byte(pTemp)==pgnoOld[i] );
-        if( !pOld->leaf ){
-          assert( leafCorrection==0 );
-          /* The right pointer of the child page pOld becomes the left
-          ** pointer of the divider cell */
-          memcpy(apCell[nCell], &pOld->aData[pOld->hdrOffset+8], 4);
-        }else{
-          assert( leafCorrection==4 );
-          if( szCell[nCell]<4 ){
-            /* Do not allow any cells smaller than 4 bytes. */
-            szCell[nCell] = 4;
-          }
-        }
-        nCell++;
-      }
-    }
   }
 
   /*
@@ -41513,6 +54115,7 @@ static int balance_nonroot(BtCursor *pCur){
       if( leafData ){ i--; }
       subtotal = 0;
       k++;
+      if( k>NB+1 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
     }
   }
   szNew[k] = subtotal;
@@ -41539,7 +54142,9 @@ static int balance_nonroot(BtCursor *pCur){
     d = r + 1 - leafData;
     assert( d<nMaxCells );
     assert( r<nMaxCells );
-    while( szRight==0 || szRight+szCell[d]+2<=szLeft-(szCell[r]+2) ){
+    while( szRight==0 
+       || (!bBulk && szRight+szCell[d]+2<=szLeft-(szCell[r]+2)) 
+    ){
       szRight += szCell[d] + 2;
       szLeft -= szCell[r] + 2;
       cntNew[i-1]--;
@@ -41550,39 +54155,61 @@ static int balance_nonroot(BtCursor *pCur){
     szNew[i-1] = szLeft;
   }
 
-  /* Either we found one or more cells (cntnew[0])>0) or we are the
+  /* Either we found one or more cells (cntnew[0])>0) or pPage is
   ** a virtual root page.  A virtual root page is when the real root
   ** page is page 1 and we are the only child of that page.
+  **
+  ** UPDATE:  The assert() below is not necessarily true if the database
+  ** file is corrupt.  The corruption will be detected and reported later
+  ** in this procedure so there is no need to act upon it now.
   */
+#if 0
   assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) );
+#endif
+
+  TRACE(("BALANCE: old: %d %d %d  ",
+    apOld[0]->pgno, 
+    nOld>=2 ? apOld[1]->pgno : 0,
+    nOld>=3 ? apOld[2]->pgno : 0
+  ));
 
   /*
   ** Allocate k new pages.  Reuse old pages where possible.
   */
-  assert( pPage->pgno>1 );
-  pageFlags = pPage->aData[0];
+  if( apOld[0]->pgno<=1 ){
+    rc = SQLITE_CORRUPT_BKPT;
+    goto balance_cleanup;
+  }
+  pageFlags = apOld[0]->aData[0];
   for(i=0; i<k; i++){
     MemPage *pNew;
     if( i<nOld ){
       pNew = apNew[i] = apOld[i];
-      pgnoNew[i] = pgnoOld[i];
       apOld[i] = 0;
       rc = sqlite3PagerWrite(pNew->pDbPage);
       nNew++;
       if( rc ) goto balance_cleanup;
     }else{
       assert( i>0 );
-      rc = allocateBtreePage(pBt, &pNew, &pgnoNew[i], pgnoNew[i-1], 0);
+      rc = allocateBtreePage(pBt, &pNew, &pgno, (bBulk ? 1 : pgno), 0);
       if( rc ) goto balance_cleanup;
       apNew[i] = pNew;
       nNew++;
+
+      /* Set the pointer-map entry for the new sibling page. */
+      if( ISAUTOVACUUM ){
+        ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);
+        if( rc!=SQLITE_OK ){
+          goto balance_cleanup;
+        }
+      }
     }
   }
 
   /* Free any old pages that were not reused as new pages.
   */
   while( i<nOld ){
-    rc = freePage(apOld[i]);
+    freePage(apOld[i], &rc);
     if( rc ) goto balance_cleanup;
     releasePage(apOld[i]);
     apOld[i] = 0;
@@ -41604,34 +54231,30 @@ static int balance_nonroot(BtCursor *pCur){
   ** about 25% faster for large insertions and deletions.
   */
   for(i=0; i<k-1; i++){
-    int minV = pgnoNew[i];
+    int minV = apNew[i]->pgno;
     int minI = i;
     for(j=i+1; j<k; j++){
-      if( pgnoNew[j]<(unsigned)minV ){
+      if( apNew[j]->pgno<(unsigned)minV ){
         minI = j;
-        minV = pgnoNew[j];
+        minV = apNew[j]->pgno;
       }
     }
     if( minI>i ){
-      int t;
       MemPage *pT;
-      t = pgnoNew[i];
       pT = apNew[i];
-      pgnoNew[i] = pgnoNew[minI];
       apNew[i] = apNew[minI];
-      pgnoNew[minI] = t;
       apNew[minI] = pT;
     }
   }
-  TRACE(("BALANCE: old: %d %d %d  new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
-    pgnoOld[0], 
-    nOld>=2 ? pgnoOld[1] : 0,
-    nOld>=3 ? pgnoOld[2] : 0,
-    pgnoNew[0], szNew[0],
-    nNew>=2 ? pgnoNew[1] : 0, nNew>=2 ? szNew[1] : 0,
-    nNew>=3 ? pgnoNew[2] : 0, nNew>=3 ? szNew[2] : 0,
-    nNew>=4 ? pgnoNew[3] : 0, nNew>=4 ? szNew[3] : 0,
-    nNew>=5 ? pgnoNew[4] : 0, nNew>=5 ? szNew[4] : 0));
+  TRACE(("new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
+    apNew[0]->pgno, szNew[0],
+    nNew>=2 ? apNew[1]->pgno : 0, nNew>=2 ? szNew[1] : 0,
+    nNew>=3 ? apNew[2]->pgno : 0, nNew>=3 ? szNew[2] : 0,
+    nNew>=4 ? apNew[3]->pgno : 0, nNew>=4 ? szNew[3] : 0,
+    nNew>=5 ? apNew[4]->pgno : 0, nNew>=5 ? szNew[4] : 0));
+
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  put4byte(pRight, apNew[nNew-1]->pgno);
 
   /*
   ** Evenly distribute the data in apCell[] across the new pages.
@@ -41642,38 +54265,18 @@ static int balance_nonroot(BtCursor *pCur){
     /* Assemble the new sibling page. */
     MemPage *pNew = apNew[i];
     assert( j<nMaxCells );
-    assert( pNew->pgno==pgnoNew[i] );
     zeroPage(pNew, pageFlags);
     assemblePage(pNew, cntNew[i]-j, &apCell[j], &szCell[j]);
     assert( pNew->nCell>0 || (nNew==1 && cntNew[0]==0) );
     assert( pNew->nOverflow==0 );
 
-    /* If this is an auto-vacuum database, update the pointer map entries
-    ** that point to the siblings that were rearranged. These can be: left
-    ** children of cells, the right-child of the page, or overflow pages
-    ** pointed to by cells.
-    */
-    if( ISAUTOVACUUM ){
-      for(k=j; k<cntNew[i]; k++){
-        assert( k<nMaxCells );
-        if( aFrom[k]==0xFF || apCopy[aFrom[k]]->pgno!=pNew->pgno ){
-          rc = ptrmapPutOvfl(pNew, k-j);
-          if( rc==SQLITE_OK && leafCorrection==0 ){
-            rc = ptrmapPut(pBt, get4byte(apCell[k]), PTRMAP_BTREE, pNew->pgno);
-          }
-          if( rc!=SQLITE_OK ){
-            goto balance_cleanup;
-          }
-        }
-      }
-    }
-
     j = cntNew[i];
 
     /* If the sibling page assembled above was not the right-most sibling,
     ** insert a divider cell into the parent page.
     */
-    if( i<nNew-1 && j<nCell ){
+    assert( i<nNew-1 || j==nCell );
+    if( j<nCell ){
       u8 *pCell;
       u8 *pTemp;
       int sz;
@@ -41681,17 +54284,9 @@ static int balance_nonroot(BtCursor *pCur){
       assert( j<nMaxCells );
       pCell = apCell[j];
       sz = szCell[j] + leafCorrection;
-      pTemp = &aSpace2[iSpace2];
+      pTemp = &aOvflSpace[iOvflSpace];
       if( !pNew->leaf ){
         memcpy(&pNew->aData[8], pCell, 4);
-        if( ISAUTOVACUUM 
-         && (aFrom[j]==0xFF || apCopy[aFrom[j]]->pgno!=pNew->pgno)
-        ){
-          rc = ptrmapPut(pBt, get4byte(pCell), PTRMAP_BTREE, pNew->pgno);
-          if( rc!=SQLITE_OK ){
-            goto balance_cleanup;
-          }
-        }
       }else if( leafData ){
         /* If the tree is a leaf-data tree, and the siblings are leaves, 
         ** then there is no divider cell in apCell[]. Instead, the divider 
@@ -41700,16 +54295,16 @@ static int balance_nonroot(BtCursor *pCur){
         */
         CellInfo info;
         j--;
-        sqlite3BtreeParseCellPtr(pNew, apCell[j], &info);
+        btreeParseCellPtr(pNew, apCell[j], &info);
         pCell = pTemp;
-        fillInCell(pParent, pCell, 0, info.nKey, 0, 0, 0, &sz);
+        sz = 4 + putVarint(&pCell[4], info.nKey);
         pTemp = 0;
       }else{
         pCell -= 4;
         /* Obscure case for non-leaf-data trees: If the cell at pCell was
         ** previously stored on a leaf node, and its reported size was 4
         ** bytes, then it may actually be smaller than this 
-        ** (see sqlite3BtreeParseCellPtr(), 4 bytes is the minimum size of
+        ** (see btreeParseCellPtr(), 4 bytes is the minimum size of
         ** any cell). But it is important to pass the correct size to 
         ** insertCell(), so reparse the cell now.
         **
@@ -41722,35 +54317,16 @@ static int balance_nonroot(BtCursor *pCur){
           sz = cellSizePtr(pParent, pCell);
         }
       }
-      iSpace2 += sz;
-      assert( sz<=pBt->pageSize/4 );
-      assert( iSpace2<=pBt->pageSize );
-      rc = insertCell(pParent, nxDiv, pCell, sz, pTemp, 4);
+      iOvflSpace += sz;
+      assert( sz<=pBt->maxLocal+23 );
+      assert( iOvflSpace <= (int)pBt->pageSize );
+      insertCell(pParent, nxDiv, pCell, sz, pTemp, pNew->pgno, &rc);
       if( rc!=SQLITE_OK ) goto balance_cleanup;
       assert( sqlite3PagerIswriteable(pParent->pDbPage) );
-      put4byte(findOverflowCell(pParent,nxDiv), pNew->pgno);
 
-      /* If this is an auto-vacuum database, and not a leaf-data tree,
-      ** then update the pointer map with an entry for the overflow page
-      ** that the cell just inserted points to (if any).
-      */
-      if( ISAUTOVACUUM && !leafData ){
-        rc = ptrmapPutOvfl(pParent, nxDiv);
-        if( rc!=SQLITE_OK ){
-          goto balance_cleanup;
-        }
-      }
       j++;
       nxDiv++;
     }
-
-    /* Set the pointer-map entry for the new sibling page. */
-    if( ISAUTOVACUUM ){
-      rc = ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno);
-      if( rc!=SQLITE_OK ){
-        goto balance_cleanup;
-      }
-    }
   }
   assert( j==nCell );
   assert( nOld>0 );
@@ -41758,43 +54334,144 @@ static int balance_nonroot(BtCursor *pCur){
   if( (pageFlags & PTF_LEAF)==0 ){
     u8 *zChild = &apCopy[nOld-1]->aData[8];
     memcpy(&apNew[nNew-1]->aData[8], zChild, 4);
-    if( ISAUTOVACUUM ){
-      rc = ptrmapPut(pBt, get4byte(zChild), PTRMAP_BTREE, apNew[nNew-1]->pgno);
-      if( rc!=SQLITE_OK ){
-        goto balance_cleanup;
-      }
-    }
-  }
-  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
-  if( nxDiv==pParent->nCell+pParent->nOverflow ){
-    /* Right-most sibling is the right-most child of pParent */
-    put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew[nNew-1]);
-  }else{
-    /* Right-most sibling is the left child of the first entry in pParent
-    ** past the right-most divider entry */
-    put4byte(findOverflowCell(pParent, nxDiv), pgnoNew[nNew-1]);
   }
 
-  /*
-  ** Balance the parent page.  Note that the current page (pPage) might
-  ** have been added to the freelist so it might no longer be initialized.
-  ** But the parent page will always be initialized.
-  */
+  if( isRoot && pParent->nCell==0 && pParent->hdrOffset<=apNew[0]->nFree ){
+    /* The root page of the b-tree now contains no cells. The only sibling
+    ** page is the right-child of the parent. Copy the contents of the
+    ** child page into the parent, decreasing the overall height of the
+    ** b-tree structure by one. This is described as the "balance-shallower"
+    ** sub-algorithm in some documentation.
+    **
+    ** If this is an auto-vacuum database, the call to copyNodeContent() 
+    ** sets all pointer-map entries corresponding to database image pages 
+    ** for which the pointer is stored within the content being copied.
+    **
+    ** The second assert below verifies that the child page is defragmented
+    ** (it must be, as it was just reconstructed using assemblePage()). This
+    ** is important if the parent page happens to be page 1 of the database
+    ** image.  */
+    assert( nNew==1 );
+    assert( apNew[0]->nFree == 
+        (get2byte(&apNew[0]->aData[5])-apNew[0]->cellOffset-apNew[0]->nCell*2) 
+    );
+    copyNodeContent(apNew[0], pParent, &rc);
+    freePage(apNew[0], &rc);
+  }else if( ISAUTOVACUUM ){
+    /* Fix the pointer-map entries for all the cells that were shifted around. 
+    ** There are several different types of pointer-map entries that need to
+    ** be dealt with by this routine. Some of these have been set already, but
+    ** many have not. The following is a summary:
+    **
+    **   1) The entries associated with new sibling pages that were not
+    **      siblings when this function was called. These have already
+    **      been set. We don't need to worry about old siblings that were
+    **      moved to the free-list - the freePage() code has taken care
+    **      of those.
+    **
+    **   2) The pointer-map entries associated with the first overflow
+    **      page in any overflow chains used by new divider cells. These 
+    **      have also already been taken care of by the insertCell() code.
+    **
+    **   3) If the sibling pages are not leaves, then the child pages of
+    **      cells stored on the sibling pages may need to be updated.
+    **
+    **   4) If the sibling pages are not internal intkey nodes, then any
+    **      overflow pages used by these cells may need to be updated
+    **      (internal intkey nodes never contain pointers to overflow pages).
+    **
+    **   5) If the sibling pages are not leaves, then the pointer-map
+    **      entries for the right-child pages of each sibling may need
+    **      to be updated.
+    **
+    ** Cases 1 and 2 are dealt with above by other code. The next
+    ** block deals with cases 3 and 4 and the one after that, case 5. Since
+    ** setting a pointer map entry is a relatively expensive operation, this
+    ** code only sets pointer map entries for child or overflow pages that have
+    ** actually moved between pages.  */
+    MemPage *pNew = apNew[0];
+    MemPage *pOld = apCopy[0];
+    int nOverflow = pOld->nOverflow;
+    int iNextOld = pOld->nCell + nOverflow;
+    int iOverflow = (nOverflow ? pOld->aiOvfl[0] : -1);
+    j = 0;                             /* Current 'old' sibling page */
+    k = 0;                             /* Current 'new' sibling page */
+    for(i=0; i<nCell; i++){
+      int isDivider = 0;
+      while( i==iNextOld ){
+        /* Cell i is the cell immediately following the last cell on old
+        ** sibling page j. If the siblings are not leaf pages of an
+        ** intkey b-tree, then cell i was a divider cell. */
+        assert( j+1 < ArraySize(apCopy) );
+        assert( j+1 < nOld );
+        pOld = apCopy[++j];
+        iNextOld = i + !leafData + pOld->nCell + pOld->nOverflow;
+        if( pOld->nOverflow ){
+          nOverflow = pOld->nOverflow;
+          iOverflow = i + !leafData + pOld->aiOvfl[0];
+        }
+        isDivider = !leafData;  
+      }
+
+      assert(nOverflow>0 || iOverflow<i );
+      assert(nOverflow<2 || pOld->aiOvfl[0]==pOld->aiOvfl[1]-1);
+      assert(nOverflow<3 || pOld->aiOvfl[1]==pOld->aiOvfl[2]-1);
+      if( i==iOverflow ){
+        isDivider = 1;
+        if( (--nOverflow)>0 ){
+          iOverflow++;
+        }
+      }
+
+      if( i==cntNew[k] ){
+        /* Cell i is the cell immediately following the last cell on new
+        ** sibling page k. If the siblings are not leaf pages of an
+        ** intkey b-tree, then cell i is a divider cell.  */
+        pNew = apNew[++k];
+        if( !leafData ) continue;
+      }
+      assert( j<nOld );
+      assert( k<nNew );
+
+      /* If the cell was originally divider cell (and is not now) or
+      ** an overflow cell, or if the cell was located on a different sibling
+      ** page before the balancing, then the pointer map entries associated
+      ** with any child or overflow pages need to be updated.  */
+      if( isDivider || pOld->pgno!=pNew->pgno ){
+        if( !leafCorrection ){
+          ptrmapPut(pBt, get4byte(apCell[i]), PTRMAP_BTREE, pNew->pgno, &rc);
+        }
+        if( szCell[i]>pNew->minLocal ){
+          ptrmapPutOvflPtr(pNew, apCell[i], &rc);
+        }
+      }
+    }
+
+    if( !leafCorrection ){
+      for(i=0; i<nNew; i++){
+        u32 key = get4byte(&apNew[i]->aData[8]);
+        ptrmapPut(pBt, key, PTRMAP_BTREE, apNew[i]->pgno, &rc);
+      }
+    }
+
+#if 0
+    /* The ptrmapCheckPages() contains assert() statements that verify that
+    ** all pointer map pages are set correctly. This is helpful while 
+    ** debugging. This is usually disabled because a corrupt database may
+    ** cause an assert() statement to fail.  */
+    ptrmapCheckPages(apNew, nNew);
+    ptrmapCheckPages(&pParent, 1);
+#endif
+  }
+
   assert( pParent->isInit );
-  sqlite3ScratchFree(apCell);
-  apCell = 0;
-  TRACE(("BALANCE: finished with %d: old=%d new=%d cells=%d\n",
-          pPage->pgno, nOld, nNew, nCell));
-  pPage->nOverflow = 0;
-  releasePage(pPage);
-  pCur->iPage--;
-  rc = balance(pCur, 0);
-  
+  TRACE(("BALANCE: finished: old=%d new=%d cells=%d\n",
+          nOld, nNew, nCell));
+
   /*
   ** Cleanup before returning.
   */
 balance_cleanup:
-  sqlite3PageFree(aSpace2);
   sqlite3ScratchFree(apCell);
   for(i=0; i<nOld; i++){
     releasePage(apOld[i]);
@@ -41802,288 +54479,202 @@ balance_cleanup:
   for(i=0; i<nNew; i++){
     releasePage(apNew[i]);
   }
-  pCur->apPage[pCur->iPage]->nOverflow = 0;
 
   return rc;
 }
-
-/*
-** This routine is called for the root page of a btree when the root
-** page contains no cells.  This is an opportunity to make the tree
-** shallower by one level.
-*/
-static int balance_shallower(BtCursor *pCur){
-  MemPage *pPage;              /* Root page of B-Tree */
-  MemPage *pChild;             /* The only child page of pPage */
-  Pgno pgnoChild;              /* Page number for pChild */
-  int rc = SQLITE_OK;          /* Return code from subprocedures */
-  BtShared *pBt;                  /* The main BTree structure */
-  int mxCellPerPage;           /* Maximum number of cells per page */
-  u8 **apCell;                 /* All cells from pages being balanced */
-  u16 *szCell;                 /* Local size of all cells */
-
-  assert( pCur->iPage==0 );
-  pPage = pCur->apPage[0];
-
-  assert( pPage->nCell==0 );
-  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  pBt = pPage->pBt;
-  mxCellPerPage = MX_CELL(pBt);
-  apCell = sqlite3Malloc( mxCellPerPage*(sizeof(u8*)+sizeof(u16)) );
-  if( apCell==0 ) return SQLITE_NOMEM;
-  szCell = (u16*)&apCell[mxCellPerPage];
-  if( pPage->leaf ){
-    /* The table is completely empty */
-    TRACE(("BALANCE: empty table %d\n", pPage->pgno));
-  }else{
-    /* The root page is empty but has one child.  Transfer the
-    ** information from that one child into the root page if it 
-    ** will fit.  This reduces the depth of the tree by one.
-    **
-    ** If the root page is page 1, it has less space available than
-    ** its child (due to the 100 byte header that occurs at the beginning
-    ** of the database fle), so it might not be able to hold all of the 
-    ** information currently contained in the child.  If this is the 
-    ** case, then do not do the transfer.  Leave page 1 empty except
-    ** for the right-pointer to the child page.  The child page becomes
-    ** the virtual root of the tree.
-    */
-    VVA_ONLY( pCur->pagesShuffled = 1 );
-    pgnoChild = get4byte(&pPage->aData[pPage->hdrOffset+8]);
-    assert( pgnoChild>0 );
-    assert( pgnoChild<=pagerPagecount(pPage->pBt) );
-    rc = sqlite3BtreeGetPage(pPage->pBt, pgnoChild, &pChild, 0);
-    if( rc ) goto end_shallow_balance;
-    if( pPage->pgno==1 ){
-      rc = sqlite3BtreeInitPage(pChild);
-      if( rc ) goto end_shallow_balance;
-      assert( pChild->nOverflow==0 );
-      if( pChild->nFree>=100 ){
-        /* The child information will fit on the root page, so do the
-        ** copy */
-        int i;
-        zeroPage(pPage, pChild->aData[0]);
-        for(i=0; i<pChild->nCell; i++){
-          apCell[i] = findCell(pChild,i);
-          szCell[i] = cellSizePtr(pChild, apCell[i]);
-        }
-        assemblePage(pPage, pChild->nCell, apCell, szCell);
-        /* Copy the right-pointer of the child to the parent. */
-        assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-        put4byte(&pPage->aData[pPage->hdrOffset+8], 
-            get4byte(&pChild->aData[pChild->hdrOffset+8]));
-        rc = freePage(pChild);
-        TRACE(("BALANCE: child %d transfer to page 1\n", pChild->pgno));
-      }else{
-        /* The child has more information that will fit on the root.
-        ** The tree is already balanced.  Do nothing. */
-        TRACE(("BALANCE: child %d will not fit on page 1\n", pChild->pgno));
-      }
-    }else{
-      memcpy(pPage->aData, pChild->aData, pPage->pBt->usableSize);
-      pPage->isInit = 0;
-      rc = sqlite3BtreeInitPage(pPage);
-      assert( rc==SQLITE_OK );
-      freePage(pChild);
-      TRACE(("BALANCE: transfer child %d into root %d\n",
-              pChild->pgno, pPage->pgno));
-    }
-    assert( pPage->nOverflow==0 );
-#ifndef SQLITE_OMIT_AUTOVACUUM
-    if( ISAUTOVACUUM && rc==SQLITE_OK ){
-      rc = setChildPtrmaps(pPage);
-    }
+#if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_M_ARM)
+#pragma optimize("", on)
 #endif
-    releasePage(pChild);
-  }
-end_shallow_balance:
-  sqlite3_free(apCell);
-  return rc;
-}
 
 
 /*
-** The root page is overfull
+** This function is called when the root page of a b-tree structure is
+** overfull (has one or more overflow pages).
 **
-** When this happens, Create a new child page and copy the
-** contents of the root into the child.  Then make the root
-** page an empty page with rightChild pointing to the new
-** child.   Finally, call balance_internal() on the new child
-** to cause it to split.
+** A new child page is allocated and the contents of the current root
+** page, including overflow cells, are copied into the child. The root
+** page is then overwritten to make it an empty page with the right-child 
+** pointer pointing to the new page.
+**
+** Before returning, all pointer-map entries corresponding to pages 
+** that the new child-page now contains pointers to are updated. The
+** entry corresponding to the new right-child pointer of the root
+** page is also updated.
+**
+** If successful, *ppChild is set to contain a reference to the child 
+** page and SQLITE_OK is returned. In this case the caller is required
+** to call releasePage() on *ppChild exactly once. If an error occurs,
+** an error code is returned and *ppChild is set to 0.
 */
-static int balance_deeper(BtCursor *pCur){
-  int rc;             /* Return value from subprocedures */
-  MemPage *pPage;     /* Pointer to the root page */
-  MemPage *pChild;    /* Pointer to a new child page */
-  Pgno pgnoChild;     /* Page number of the new child page */
-  BtShared *pBt;         /* The BTree */
-  int usableSize;     /* Total usable size of a page */
-  u8 *data;           /* Content of the parent page */
-  u8 *cdata;          /* Content of the child page */
-  int hdr;            /* Offset to page header in parent */
-  int cbrk;           /* Offset to content of first cell in parent */
+static int balance_deeper(MemPage *pRoot, MemPage **ppChild){
+  int rc;                        /* Return value from subprocedures */
+  MemPage *pChild = 0;           /* Pointer to a new child page */
+  Pgno pgnoChild = 0;            /* Page number of the new child page */
+  BtShared *pBt = pRoot->pBt;    /* The BTree */
 
-  assert( pCur->iPage==0 );
-  assert( pCur->apPage[0]->nOverflow>0 );
-
-  VVA_ONLY( pCur->pagesShuffled = 1 );
-  pPage = pCur->apPage[0];
-  pBt = pPage->pBt;
+  assert( pRoot->nOverflow>0 );
   assert( sqlite3_mutex_held(pBt->mutex) );
-  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-  rc = allocateBtreePage(pBt, &pChild, &pgnoChild, pPage->pgno, 0);
-  if( rc ) return rc;
-  assert( sqlite3PagerIswriteable(pChild->pDbPage) );
-  usableSize = pBt->usableSize;
-  data = pPage->aData;
-  hdr = pPage->hdrOffset;
-  cbrk = get2byte(&data[hdr+5]);
-  cdata = pChild->aData;
-  memcpy(cdata, &data[hdr], pPage->cellOffset+2*pPage->nCell-hdr);
-  memcpy(&cdata[cbrk], &data[cbrk], usableSize-cbrk);
 
-  assert( pChild->isInit==0 );
-  rc = sqlite3BtreeInitPage(pChild);
+  /* Make pRoot, the root page of the b-tree, writable. Allocate a new 
+  ** page that will become the new right-child of pPage. Copy the contents
+  ** of the node stored on pRoot into the new child page.
+  */
+  rc = sqlite3PagerWrite(pRoot->pDbPage);
   if( rc==SQLITE_OK ){
-    int nCopy = pPage->nOverflow*sizeof(pPage->aOvfl[0]);
-    memcpy(pChild->aOvfl, pPage->aOvfl, nCopy);
-    pChild->nOverflow = pPage->nOverflow;
-    if( pChild->nOverflow ){
-      pChild->nFree = 0;
-    }
-    assert( pChild->nCell==pPage->nCell );
-    assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-    zeroPage(pPage, pChild->aData[0] & ~PTF_LEAF);
-    put4byte(&pPage->aData[pPage->hdrOffset+8], pgnoChild);
-    TRACE(("BALANCE: copy root %d into %d\n", pPage->pgno, pChild->pgno));
+    rc = allocateBtreePage(pBt,&pChild,&pgnoChild,pRoot->pgno,0);
+    copyNodeContent(pRoot, pChild, &rc);
     if( ISAUTOVACUUM ){
-      rc = ptrmapPut(pBt, pChild->pgno, PTRMAP_BTREE, pPage->pgno);
-#ifndef SQLITE_OMIT_AUTOVACUUM
-      if( rc==SQLITE_OK ){
-        rc = setChildPtrmaps(pChild);
-      }
-      if( rc ){
-        pChild->nOverflow = 0;
-      }
-#endif
+      ptrmapPut(pBt, pgnoChild, PTRMAP_BTREE, pRoot->pgno, &rc);
     }
   }
-
-  if( rc==SQLITE_OK ){
-    pCur->iPage++;
-    pCur->apPage[1] = pChild;
-    pCur->aiIdx[0] = 0;
-    rc = balance_nonroot(pCur);
-  }else{
+  if( rc ){
+    *ppChild = 0;
     releasePage(pChild);
+    return rc;
   }
+  assert( sqlite3PagerIswriteable(pChild->pDbPage) );
+  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
+  assert( pChild->nCell==pRoot->nCell );
 
-  return rc;
+  TRACE(("BALANCE: copy root %d into %d\n", pRoot->pgno, pChild->pgno));
+
+  /* Copy the overflow cells from pRoot to pChild */
+  memcpy(pChild->aiOvfl, pRoot->aiOvfl,
+         pRoot->nOverflow*sizeof(pRoot->aiOvfl[0]));
+  memcpy(pChild->apOvfl, pRoot->apOvfl,
+         pRoot->nOverflow*sizeof(pRoot->apOvfl[0]));
+  pChild->nOverflow = pRoot->nOverflow;
+
+  /* Zero the contents of pRoot. Then install pChild as the right-child. */
+  zeroPage(pRoot, pChild->aData[0] & ~PTF_LEAF);
+  put4byte(&pRoot->aData[pRoot->hdrOffset+8], pgnoChild);
+
+  *ppChild = pChild;
+  return SQLITE_OK;
 }
 
 /*
 ** The page that pCur currently points to has just been modified in
 ** some way. This function figures out if this modification means the
 ** tree needs to be balanced, and if so calls the appropriate balancing 
-** routine.
-** 
-** Parameter isInsert is true if a new cell was just inserted into the
-** page, or false otherwise.
+** routine. Balancing routines are:
+**
+**   balance_quick()
+**   balance_deeper()
+**   balance_nonroot()
 */
-static int balance(BtCursor *pCur, int isInsert){
+static int balance(BtCursor *pCur){
   int rc = SQLITE_OK;
-  MemPage *pPage = pCur->apPage[pCur->iPage];
+  const int nMin = pCur->pBt->usableSize * 2 / 3;
+  u8 aBalanceQuickSpace[13];
+  u8 *pFree = 0;
 
-  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  if( pCur->iPage==0 ){
-    rc = sqlite3PagerWrite(pPage->pDbPage);
-    if( rc==SQLITE_OK && pPage->nOverflow>0 ){
-      rc = balance_deeper(pCur);
-      assert( pCur->apPage[0]==pPage );
-      assert( pPage->nOverflow==0 || rc!=SQLITE_OK );
-    }
-    if( rc==SQLITE_OK && pPage->nCell==0 ){
-      rc = balance_shallower(pCur);
-      assert( pCur->apPage[0]==pPage );
-      assert( pPage->nOverflow==0 || rc!=SQLITE_OK );
-    }
-  }else{
-    if( pPage->nOverflow>0 || 
-        (!isInsert && pPage->nFree>pPage->pBt->usableSize*2/3) ){
-      rc = balance_nonroot(pCur);
+  TESTONLY( int balance_quick_called = 0 );
+  TESTONLY( int balance_deeper_called = 0 );
+
+  do {
+    int iPage = pCur->iPage;
+    MemPage *pPage = pCur->apPage[iPage];
+
+    if( iPage==0 ){
+      if( pPage->nOverflow ){
+        /* The root page of the b-tree is overfull. In this case call the
+        ** balance_deeper() function to create a new child for the root-page
+        ** and copy the current contents of the root-page to it. The
+        ** next iteration of the do-loop will balance the child page.
+        */ 
+        assert( (balance_deeper_called++)==0 );
+        rc = balance_deeper(pPage, &pCur->apPage[1]);
+        if( rc==SQLITE_OK ){
+          pCur->iPage = 1;
+          pCur->aiIdx[0] = 0;
+          pCur->aiIdx[1] = 0;
+          assert( pCur->apPage[1]->nOverflow );
+        }
+      }else{
+        break;
+      }
+    }else if( pPage->nOverflow==0 && pPage->nFree<=nMin ){
+      break;
+    }else{
+      MemPage * const pParent = pCur->apPage[iPage-1];
+      int const iIdx = pCur->aiIdx[iPage-1];
+
+      rc = sqlite3PagerWrite(pParent->pDbPage);
+      if( rc==SQLITE_OK ){
+#ifndef SQLITE_OMIT_QUICKBALANCE
+        if( pPage->hasData
+         && pPage->nOverflow==1
+         && pPage->aiOvfl[0]==pPage->nCell
+         && pParent->pgno!=1
+         && pParent->nCell==iIdx
+        ){
+          /* Call balance_quick() to create a new sibling of pPage on which
+          ** to store the overflow cell. balance_quick() inserts a new cell
+          ** into pParent, which may cause pParent overflow. If this
+          ** happens, the next interation of the do-loop will balance pParent 
+          ** use either balance_nonroot() or balance_deeper(). Until this
+          ** happens, the overflow cell is stored in the aBalanceQuickSpace[]
+          ** buffer. 
+          **
+          ** The purpose of the following assert() is to check that only a
+          ** single call to balance_quick() is made for each call to this
+          ** function. If this were not verified, a subtle bug involving reuse
+          ** of the aBalanceQuickSpace[] might sneak in.
+          */
+          assert( (balance_quick_called++)==0 );
+          rc = balance_quick(pParent, pPage, aBalanceQuickSpace);
+        }else
+#endif
+        {
+          /* In this case, call balance_nonroot() to redistribute cells
+          ** between pPage and up to 2 of its sibling pages. This involves
+          ** modifying the contents of pParent, which may cause pParent to
+          ** become overfull or underfull. The next iteration of the do-loop
+          ** will balance the parent page to correct this.
+          ** 
+          ** If the parent page becomes overfull, the overflow cell or cells
+          ** are stored in the pSpace buffer allocated immediately below. 
+          ** A subsequent iteration of the do-loop will deal with this by
+          ** calling balance_nonroot() (balance_deeper() may be called first,
+          ** but it doesn't deal with overflow cells - just moves them to a
+          ** different page). Once this subsequent call to balance_nonroot() 
+          ** has completed, it is safe to release the pSpace buffer used by
+          ** the previous call, as the overflow cell data will have been 
+          ** copied either into the body of a database page or into the new
+          ** pSpace buffer passed to the latter call to balance_nonroot().
+          */
+          u8 *pSpace = sqlite3PageMalloc(pCur->pBt->pageSize);
+          rc = balance_nonroot(pParent, iIdx, pSpace, iPage==1, pCur->hints);
+          if( pFree ){
+            /* If pFree is not NULL, it points to the pSpace buffer used 
+            ** by a previous call to balance_nonroot(). Its contents are
+            ** now stored either on real database pages or within the 
+            ** new pSpace buffer, so it may be safely freed here. */
+            sqlite3PageFree(pFree);
+          }
+
+          /* The pSpace buffer will be freed after the next call to
+          ** balance_nonroot(), or just before this function returns, whichever
+          ** comes first. */
+          pFree = pSpace;
+        }
+      }
+
+      pPage->nOverflow = 0;
+
+      /* The next iteration of the do-loop balances the parent page. */
+      releasePage(pPage);
+      pCur->iPage--;
     }
+  }while( rc==SQLITE_OK );
+
+  if( pFree ){
+    sqlite3PageFree(pFree);
   }
   return rc;
 }
 
-/*
-** This routine checks all cursors that point to table pgnoRoot.
-** If any of those cursors were opened with wrFlag==0 in a different
-** database connection (a database connection that shares the pager
-** cache with the current connection) and that other connection 
-** is not in the ReadUncommmitted state, then this routine returns 
-** SQLITE_LOCKED.
-**
-** As well as cursors with wrFlag==0, cursors with wrFlag==1 and 
-** isIncrblobHandle==1 are also considered 'read' cursors. Incremental 
-** blob cursors are used for both reading and writing.
-**
-** When pgnoRoot is the root page of an intkey table, this function is also
-** responsible for invalidating incremental blob cursors when the table row
-** on which they are opened is deleted or modified. Cursors are invalidated
-** according to the following rules:
-**
-**   1) When BtreeClearTable() is called to completely delete the contents
-**      of a B-Tree table, pExclude is set to zero and parameter iRow is 
-**      set to non-zero. In this case all incremental blob cursors open
-**      on the table rooted at pgnoRoot are invalidated.
-**
-**   2) When BtreeInsert(), BtreeDelete() or BtreePutData() is called to 
-**      modify a table row via an SQL statement, pExclude is set to the 
-**      write cursor used to do the modification and parameter iRow is set
-**      to the integer row id of the B-Tree entry being modified. Unless
-**      pExclude is itself an incremental blob cursor, then all incremental
-**      blob cursors open on row iRow of the B-Tree are invalidated.
-**
-**   3) If both pExclude and iRow are set to zero, no incremental blob 
-**      cursors are invalidated.
-*/
-static int checkReadLocks(
-  Btree *pBtree, 
-  Pgno pgnoRoot, 
-  BtCursor *pExclude,
-  i64 iRow
-){
-  BtCursor *p;
-  BtShared *pBt = pBtree->pBt;
-  sqlite3 *db = pBtree->db;
-  assert( sqlite3BtreeHoldsMutex(pBtree) );
-  for(p=pBt->pCursor; p; p=p->pNext){
-    if( p==pExclude ) continue;
-    if( p->pgnoRoot!=pgnoRoot ) continue;
-#ifndef SQLITE_OMIT_INCRBLOB
-    if( p->isIncrblobHandle && ( 
-         (!pExclude && iRow)
-      || (pExclude && !pExclude->isIncrblobHandle && p->info.nKey==iRow)
-    )){
-      p->eState = CURSOR_INVALID;
-    }
-#endif
-    if( p->eState!=CURSOR_VALID ) continue;
-    if( p->wrFlag==0 
-#ifndef SQLITE_OMIT_INCRBLOB
-     || p->isIncrblobHandle
-#endif
-    ){
-      sqlite3 *dbOther = p->pBtree->db;
-      if( dbOther==0 ||
-         (dbOther!=db && (dbOther->flags & SQLITE_ReadUncommitted)==0) ){
-        return SQLITE_LOCKED;
-      }
-    }
-  }
-  return SQLITE_OK;
-}
 
 /*
 ** Insert a new record into the BTree.  The key is given by (pKey,nKey)
@@ -42093,17 +54684,31 @@ static int checkReadLocks(
 **
 ** For an INTKEY table, only the nKey value of the key is used.  pKey is
 ** ignored.  For a ZERODATA table, the pData and nData are both ignored.
+**
+** If the seekResult parameter is non-zero, then a successful call to
+** MovetoUnpacked() to seek cursor pCur to (pKey, nKey) has already
+** been performed. seekResult is the search result returned (a negative
+** number if pCur points at an entry that is smaller than (pKey, nKey), or
+** a positive value if pCur points at an etry that is larger than 
+** (pKey, nKey)). 
+**
+** If the seekResult parameter is non-zero, then the caller guarantees that
+** cursor pCur is pointing at the existing copy of a row that is to be
+** overwritten.  If the seekResult parameter is 0, then cursor pCur may
+** point to any entry or to no entry at all and so this function has to seek
+** the cursor before the new key can be inserted.
 */
 SQLITE_PRIVATE int sqlite3BtreeInsert(
   BtCursor *pCur,                /* Insert data into the table of this cursor */
   const void *pKey, i64 nKey,    /* The key of the new record */
   const void *pData, int nData,  /* The data of the new record */
   int nZero,                     /* Number of extra 0 bytes to append to data */
-  int appendBias                 /* True if this is likely an append */
+  int appendBias,                /* True if this is likely an append */
+  int seekResult                 /* Result of prior MovetoUnpacked() call */
 ){
   int rc;
-  int loc;
-  int szNew;
+  int loc = seekResult;          /* -1: before desired location  +1: after */
+  int szNew = 0;
   int idx;
   MemPage *pPage;
   Btree *p = pCur->pBtree;
@@ -42111,29 +54716,54 @@ SQLITE_PRIVATE int sqlite3BtreeInsert(
   unsigned char *oldCell;
   unsigned char *newCell = 0;
 
-  assert( cursorHoldsMutex(pCur) );
-  assert( pBt->inTransaction==TRANS_WRITE );
-  assert( !pBt->readOnly );
-  assert( pCur->wrFlag );
-  if( checkReadLocks(pCur->pBtree, pCur->pgnoRoot, pCur, nKey) ){
-    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
-  }
   if( pCur->eState==CURSOR_FAULT ){
-    return pCur->skip;
+    assert( pCur->skipNext!=SQLITE_OK );
+    return pCur->skipNext;
   }
 
-  /* Save the positions of any other cursors open on this table */
-  sqlite3BtreeClearCursor(pCur);
-  if( 
-    SQLITE_OK!=(rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur)) ||
-    SQLITE_OK!=(rc = sqlite3BtreeMoveto(pCur, pKey, nKey, appendBias, &loc))
-  ){
-    return rc;
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->wrFlag && pBt->inTransaction==TRANS_WRITE
+              && (pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
+
+  /* Assert that the caller has been consistent. If this cursor was opened
+  ** expecting an index b-tree, then the caller should be inserting blob
+  ** keys with no associated data. If the cursor was opened expecting an
+  ** intkey table, the caller should be inserting integer keys with a
+  ** blob of associated data.  */
+  assert( (pKey==0)==(pCur->pKeyInfo==0) );
+
+  /* Save the positions of any other cursors open on this table.
+  **
+  ** In some cases, the call to btreeMoveto() below is a no-op. For
+  ** example, when inserting data into a table with auto-generated integer
+  ** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the 
+  ** integer key to use. It then calls this function to actually insert the 
+  ** data into the intkey B-Tree. In this case btreeMoveto() recognizes
+  ** that the cursor is already where it needs to be and returns without
+  ** doing any work. To avoid thwarting these optimizations, it is important
+  ** not to clear the cursor here.
+  */
+  rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
+  if( rc ) return rc;
+
+  /* If this is an insert into a table b-tree, invalidate any incrblob 
+  ** cursors open on the row being replaced (assuming this is a replace
+  ** operation - if it is not, the following is a no-op).  */
+  if( pCur->pKeyInfo==0 ){
+    invalidateIncrblobCursors(p, nKey, 0);
   }
 
+  if( !loc ){
+    rc = btreeMoveto(pCur, pKey, nKey, appendBias, &loc);
+    if( rc ) return rc;
+  }
+  assert( pCur->eState==CURSOR_VALID || (pCur->eState==CURSOR_INVALID && loc) );
+
   pPage = pCur->apPage[pCur->iPage];
   assert( pPage->intKey || nKey>=0 );
   assert( pPage->leaf || !pPage->intKey );
+
   TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
           pCur->pgnoRoot, nKey, nData, pPage->pgno,
           loc==0 ? "overwrite" : "new entry"));
@@ -42144,9 +54774,9 @@ SQLITE_PRIVATE int sqlite3BtreeInsert(
   rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
   if( rc ) goto end_insert;
   assert( szNew==cellSizePtr(pPage, newCell) );
-  assert( szNew<=MX_CELL_SIZE(pBt) );
+  assert( szNew <= MX_CELL_SIZE(pBt) );
   idx = pCur->aiIdx[pCur->iPage];
-  if( loc==0 && CURSOR_VALID==pCur->eState ){
+  if( loc==0 ){
     u16 szOld;
     assert( idx<pPage->nCell );
     rc = sqlite3PagerWrite(pPage->pDbPage);
@@ -42159,31 +54789,51 @@ SQLITE_PRIVATE int sqlite3BtreeInsert(
     }
     szOld = cellSizePtr(pPage, oldCell);
     rc = clearCell(pPage, oldCell);
+    dropCell(pPage, idx, szOld, &rc);
     if( rc ) goto end_insert;
-    rc = dropCell(pPage, idx, szOld);
-    if( rc!=SQLITE_OK ) {
-      goto end_insert;
-    }
   }else if( loc<0 && pPage->nCell>0 ){
     assert( pPage->leaf );
     idx = ++pCur->aiIdx[pCur->iPage];
-    pCur->info.nSize = 0;
-    pCur->validNKey = 0;
   }else{
     assert( pPage->leaf );
   }
-  rc = insertCell(pPage, idx, newCell, szNew, 0, 0);
-  if( rc==SQLITE_OK ){
-    rc = balance(pCur, 1);
-  }
+  insertCell(pPage, idx, newCell, szNew, 0, 0, &rc);
+  assert( rc!=SQLITE_OK || pPage->nCell>0 || pPage->nOverflow>0 );
 
-  /* Must make sure nOverflow is reset to zero even if the balance()
-  ** fails.  Internal data structure corruption will result otherwise. */
-  pCur->apPage[pCur->iPage]->nOverflow = 0;
+  /* If no error has occured and pPage has an overflow cell, call balance() 
+  ** to redistribute the cells within the tree. Since balance() may move
+  ** the cursor, zero the BtCursor.info.nSize and BtCursor.validNKey
+  ** variables.
+  **
+  ** Previous versions of SQLite called moveToRoot() to move the cursor
+  ** back to the root page as balance() used to invalidate the contents
+  ** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,
+  ** set the cursor state to "invalid". This makes common insert operations
+  ** slightly faster.
+  **
+  ** There is a subtle but important optimization here too. When inserting
+  ** multiple records into an intkey b-tree using a single cursor (as can
+  ** happen while processing an "INSERT INTO ... SELECT" statement), it
+  ** is advantageous to leave the cursor pointing to the last entry in
+  ** the b-tree if possible. If the cursor is left pointing to the last
+  ** entry in the table, and the next row inserted has an integer key
+  ** larger than the largest existing key, it is possible to insert the
+  ** row without seeking the cursor. This can be a big performance boost.
+  */
+  pCur->info.nSize = 0;
+  pCur->validNKey = 0;
+  if( rc==SQLITE_OK && pPage->nOverflow ){
+    rc = balance(pCur);
 
-  if( rc==SQLITE_OK ){
-    moveToRoot(pCur);
+    /* Must make sure nOverflow is reset to zero even if the balance()
+    ** fails. Internal data structure corruption will result otherwise. 
+    ** Also, set the cursor state to invalid. This stops saveCursorPosition()
+    ** from trying to save the current position of the cursor.  */
+    pCur->apPage[pCur->iPage]->nOverflow = 0;
+    pCur->eState = CURSOR_INVALID;
   }
+  assert( pCur->apPage[pCur->iPage]->nOverflow==0 );
+
 end_insert:
   return rc;
 }
@@ -42193,195 +54843,112 @@ end_insert:
 ** is left pointing at a arbitrary location.
 */
 SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor *pCur){
-  MemPage *pPage = pCur->apPage[pCur->iPage];
-  int idx;
-  unsigned char *pCell;
-  int rc;
-  Pgno pgnoChild = 0;
   Btree *p = pCur->pBtree;
-  BtShared *pBt = p->pBt;
+  BtShared *pBt = p->pBt;              
+  int rc;                              /* Return code */
+  MemPage *pPage;                      /* Page to delete cell from */
+  unsigned char *pCell;                /* Pointer to cell to delete */
+  int iCellIdx;                        /* Index of cell to delete */
+  int iCellDepth;                      /* Depth of node containing pCell */ 
 
   assert( cursorHoldsMutex(pCur) );
-  assert( pPage->isInit );
   assert( pBt->inTransaction==TRANS_WRITE );
-  assert( !pBt->readOnly );
-  if( pCur->eState==CURSOR_FAULT ){
-    return pCur->skip;
-  }
-  if( NEVER(pCur->aiIdx[pCur->iPage]>=pPage->nCell) ){
-    return SQLITE_ERROR;  /* The cursor is not pointing to anything */
-  }
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
   assert( pCur->wrFlag );
-  if( checkReadLocks(pCur->pBtree, pCur->pgnoRoot, pCur, pCur->info.nKey) ){
-    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
-  }
+  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
+  assert( !hasReadConflicts(p, pCur->pgnoRoot) );
 
-  /* Restore the current cursor position (a no-op if the cursor is not in 
-  ** CURSOR_REQUIRESEEK state) and save the positions of any other cursors 
-  ** open on the same table. Then call sqlite3PagerWrite() on the page
-  ** that the entry will be deleted from.
-  */
-  if( 
-    (rc = restoreCursorPosition(pCur))!=0 ||
-    (rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur))!=0 ||
-    (rc = sqlite3PagerWrite(pPage->pDbPage))!=0
+  if( NEVER(pCur->aiIdx[pCur->iPage]>=pCur->apPage[pCur->iPage]->nCell) 
+   || NEVER(pCur->eState!=CURSOR_VALID)
   ){
-    return rc;
+    return SQLITE_ERROR;  /* Something has gone awry. */
   }
 
-  /* Locate the cell within its page and leave pCell pointing to the
-  ** data. The clearCell() call frees any overflow pages associated with the
-  ** cell. The cell itself is still intact.
-  */
-  idx = pCur->aiIdx[pCur->iPage];
-  pCell = findCell(pPage, idx);
+  iCellDepth = pCur->iPage;
+  iCellIdx = pCur->aiIdx[iCellDepth];
+  pPage = pCur->apPage[iCellDepth];
+  pCell = findCell(pPage, iCellIdx);
+
+  /* If the page containing the entry to delete is not a leaf page, move
+  ** the cursor to the largest entry in the tree that is smaller than
+  ** the entry being deleted. This cell will replace the cell being deleted
+  ** from the internal node. The 'previous' entry is used for this instead
+  ** of the 'next' entry, as the previous entry is always a part of the
+  ** sub-tree headed by the child page of the cell being deleted. This makes
+  ** balancing the tree following the delete operation easier.  */
   if( !pPage->leaf ){
-    pgnoChild = get4byte(pCell);
-  }
-  rc = clearCell(pPage, pCell);
-  if( rc ){
-    return rc;
-  }
-
-  if( !pPage->leaf ){
-    /*
-    ** The entry we are about to delete is not a leaf so if we do not
-    ** do something we will leave a hole on an internal page.
-    ** We have to fill the hole by moving in a cell from a leaf.  The
-    ** next Cell after the one to be deleted is guaranteed to exist and
-    ** to be a leaf so we can use it.
-    */
-    BtCursor leafCur;
-    MemPage *pLeafPage = 0;
-
-    unsigned char *pNext;
     int notUsed;
-    unsigned char *tempCell = 0;
-    assert( !pPage->intKey );
-    sqlite3BtreeGetTempCursor(pCur, &leafCur);
-    rc = sqlite3BtreeNext(&leafCur, &notUsed);
-    if( rc==SQLITE_OK ){
-      assert( leafCur.aiIdx[leafCur.iPage]==0 );
-      pLeafPage = leafCur.apPage[leafCur.iPage];
-      rc = sqlite3PagerWrite(pLeafPage->pDbPage);
-    }
-    if( rc==SQLITE_OK ){
-      int leafCursorInvalid = 0;
-      u16 szNext;
-      TRACE(("DELETE: table=%d delete internal from %d replace from leaf %d\n",
-         pCur->pgnoRoot, pPage->pgno, pLeafPage->pgno));
-      dropCell(pPage, idx, cellSizePtr(pPage, pCell));
-      pNext = findCell(pLeafPage, 0);
-      szNext = cellSizePtr(pLeafPage, pNext);
-      assert( MX_CELL_SIZE(pBt)>=szNext+4 );
-      allocateTempSpace(pBt);
-      tempCell = pBt->pTmpSpace;
-      if( tempCell==0 ){
-        rc = SQLITE_NOMEM;
-      }
-      if( rc==SQLITE_OK ){
-        rc = insertCell(pPage, idx, pNext-4, szNext+4, tempCell, 0);
-      }
-
-
-      /* The "if" statement in the next code block is critical.  The
-      ** slightest error in that statement would allow SQLite to operate
-      ** correctly most of the time but produce very rare failures.  To
-      ** guard against this, the following macros help to verify that
-      ** the "if" statement is well tested.
-      */
-      testcase( pPage->nOverflow==0 && pPage->nFree<pBt->usableSize*2/3 
-                 && pLeafPage->nFree+2+szNext > pBt->usableSize*2/3 );
-      testcase( pPage->nOverflow==0 && pPage->nFree==pBt->usableSize*2/3 
-                 && pLeafPage->nFree+2+szNext > pBt->usableSize*2/3 );
-      testcase( pPage->nOverflow==0 && pPage->nFree==pBt->usableSize*2/3+1 
-                 && pLeafPage->nFree+2+szNext > pBt->usableSize*2/3 );
-      testcase( pPage->nOverflow>0 && pPage->nFree<=pBt->usableSize*2/3
-                 && pLeafPage->nFree+2+szNext > pBt->usableSize*2/3 );
-      testcase( (pPage->nOverflow>0 || (pPage->nFree > pBt->usableSize*2/3))
-                 && pLeafPage->nFree+2+szNext == pBt->usableSize*2/3 );
-
-
-      if( (pPage->nOverflow>0 || (pPage->nFree > pBt->usableSize*2/3)) &&
-          (pLeafPage->nFree+2+szNext > pBt->usableSize*2/3)
-      ){
-        /* This branch is taken if the internal node is now either overflowing
-        ** or underfull and the leaf node will be underfull after the just cell 
-        ** copied to the internal node is deleted from it. This is a special
-        ** case because the call to balance() to correct the internal node
-        ** may change the tree structure and invalidate the contents of
-        ** the leafCur.apPage[] and leafCur.aiIdx[] arrays, which will be
-        ** used by the balance() required to correct the underfull leaf
-        ** node.
-        **
-        ** The formula used in the expression above are based on facets of
-        ** the SQLite file-format that do not change over time.
-        */
-        testcase( pPage->nFree==pBt->usableSize*2/3+1 );
-        testcase( pLeafPage->nFree+2+szNext==pBt->usableSize*2/3+1 );
-        leafCursorInvalid = 1;
-      }        
-
-      if( rc==SQLITE_OK ){
-        assert( sqlite3PagerIswriteable(pPage->pDbPage) );
-        put4byte(findOverflowCell(pPage, idx), pgnoChild);
-        VVA_ONLY( pCur->pagesShuffled = 0 );
-        rc = balance(pCur, 0);
-      }
-
-      if( rc==SQLITE_OK && leafCursorInvalid ){
-        /* The leaf-node is now underfull and so the tree needs to be 
-        ** rebalanced. However, the balance() operation on the internal
-        ** node above may have modified the structure of the B-Tree and
-        ** so the current contents of leafCur.apPage[] and leafCur.aiIdx[]
-        ** may not be trusted.
-        **
-        ** It is not possible to copy the ancestry from pCur, as the same
-        ** balance() call has invalidated the pCur->apPage[] and aiIdx[]
-        ** arrays. 
-        **
-        ** The call to saveCursorPosition() below internally saves the 
-        ** key that leafCur is currently pointing to. Currently, there
-        ** are two copies of that key in the tree - one here on the leaf
-        ** page and one on some internal node in the tree. The copy on
-        ** the leaf node is always the next key in tree-order after the 
-        ** copy on the internal node. So, the call to sqlite3BtreeNext()
-        ** calls restoreCursorPosition() to point the cursor to the copy
-        ** stored on the internal node, then advances to the next entry,
-        ** which happens to be the copy of the key on the internal node.
-        ** Net effect: leafCur is pointing back to the duplicate cell
-        ** that needs to be removed, and the leafCur.apPage[] and
-        ** leafCur.aiIdx[] arrays are correct.
-        */
-        VVA_ONLY( Pgno leafPgno = pLeafPage->pgno );
-        rc = saveCursorPosition(&leafCur);
-        if( rc==SQLITE_OK ){
-          rc = sqlite3BtreeNext(&leafCur, &notUsed);
-        }
-        pLeafPage = leafCur.apPage[leafCur.iPage];
-        assert( pLeafPage->pgno==leafPgno );
-        assert( leafCur.aiIdx[leafCur.iPage]==0 );
-      }
-
-      if( SQLITE_OK==rc
-       && SQLITE_OK==(rc = sqlite3PagerWrite(pLeafPage->pDbPage)) 
-      ){
-        dropCell(pLeafPage, 0, szNext);
-        VVA_ONLY( leafCur.pagesShuffled = 0 );
-        rc = balance(&leafCur, 0);
-        assert( leafCursorInvalid || !leafCur.pagesShuffled
-                                   || !pCur->pagesShuffled );
-      }
-    }
-    sqlite3BtreeReleaseTempCursor(&leafCur);
-  }else{
-    TRACE(("DELETE: table=%d delete from leaf %d\n",
-       pCur->pgnoRoot, pPage->pgno));
-    rc = dropCell(pPage, idx, cellSizePtr(pPage, pCell));
-    if( rc==SQLITE_OK ){
-      rc = balance(pCur, 0);
-    }
+    rc = sqlite3BtreePrevious(pCur, &notUsed);
+    if( rc ) return rc;
   }
+
+  /* Save the positions of any other cursors open on this table before
+  ** making any modifications. Make the page containing the entry to be 
+  ** deleted writable. Then free any overflow pages associated with the 
+  ** entry and finally remove the cell itself from within the page.  
+  */
+  rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
+  if( rc ) return rc;
+
+  /* If this is a delete operation to remove a row from a table b-tree,
+  ** invalidate any incrblob cursors open on the row being deleted.  */
+  if( pCur->pKeyInfo==0 ){
+    invalidateIncrblobCursors(p, pCur->info.nKey, 0);
+  }
+
+  rc = sqlite3PagerWrite(pPage->pDbPage);
+  if( rc ) return rc;
+  rc = clearCell(pPage, pCell);
+  dropCell(pPage, iCellIdx, cellSizePtr(pPage, pCell), &rc);
+  if( rc ) return rc;
+
+  /* If the cell deleted was not located on a leaf page, then the cursor
+  ** is currently pointing to the largest entry in the sub-tree headed
+  ** by the child-page of the cell that was just deleted from an internal
+  ** node. The cell from the leaf node needs to be moved to the internal
+  ** node to replace the deleted cell.  */
+  if( !pPage->leaf ){
+    MemPage *pLeaf = pCur->apPage[pCur->iPage];
+    int nCell;
+    Pgno n = pCur->apPage[iCellDepth+1]->pgno;
+    unsigned char *pTmp;
+
+    pCell = findCell(pLeaf, pLeaf->nCell-1);
+    nCell = cellSizePtr(pLeaf, pCell);
+    assert( MX_CELL_SIZE(pBt) >= nCell );
+
+    allocateTempSpace(pBt);
+    pTmp = pBt->pTmpSpace;
+
+    rc = sqlite3PagerWrite(pLeaf->pDbPage);
+    insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n, &rc);
+    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
+    if( rc ) return rc;
+  }
+
+  /* Balance the tree. If the entry deleted was located on a leaf page,
+  ** then the cursor still points to that page. In this case the first
+  ** call to balance() repairs the tree, and the if(...) condition is
+  ** never true.
+  **
+  ** Otherwise, if the entry deleted was on an internal node page, then
+  ** pCur is pointing to the leaf page from which a cell was removed to
+  ** replace the cell deleted from the internal node. This is slightly
+  ** tricky as the leaf node may be underfull, and the internal node may
+  ** be either under or overfull. In this case run the balancing algorithm
+  ** on the leaf node first. If the balance proceeds far enough up the
+  ** tree that we can be sure that any problem in the internal node has
+  ** been corrected, so be it. Otherwise, after balancing the leaf node,
+  ** walk the cursor up the tree to the internal node and balance it as 
+  ** well.  */
+  rc = balance(pCur);
+  if( rc==SQLITE_OK && pCur->iPage>iCellDepth ){
+    while( pCur->iPage>iCellDepth ){
+      releasePage(pCur->apPage[pCur->iPage--]);
+    }
+    rc = balance(pCur);
+  }
+
   if( rc==SQLITE_OK ){
     moveToRoot(pCur);
   }
@@ -42399,15 +54966,16 @@ SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor *pCur){
 **     BTREE_INTKEY|BTREE_LEAFDATA     Used for SQL tables with rowid keys
 **     BTREE_ZERODATA                  Used for SQL indices
 */
-static int btreeCreateTable(Btree *p, int *piTable, int flags){
+static int btreeCreateTable(Btree *p, int *piTable, int createTabFlags){
   BtShared *pBt = p->pBt;
   MemPage *pRoot;
   Pgno pgnoRoot;
   int rc;
+  int ptfFlags;          /* Page-type flage for the root page of new table */
 
   assert( sqlite3BtreeHoldsMutex(p) );
   assert( pBt->inTransaction==TRANS_WRITE );
-  assert( !pBt->readOnly );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
 
 #ifdef SQLITE_OMIT_AUTOVACUUM
   rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
@@ -42430,10 +54998,7 @@ static int btreeCreateTable(Btree *p, int *piTable, int flags){
     ** root page of the new table should go. meta[3] is the largest root-page
     ** created so far, so the new root-page is (meta[3]+1).
     */
-    rc = sqlite3BtreeGetMeta(p, 4, &pgnoRoot);
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
+    sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &pgnoRoot);
     pgnoRoot++;
 
     /* The new root-page may not be allocated on a pointer-map page, or the
@@ -42461,28 +55026,26 @@ static int btreeCreateTable(Btree *p, int *piTable, int flags){
       ** by extending the file), the current page at position pgnoMove
       ** is already journaled.
       */
-      u8 eType;
-      Pgno iPtrPage;
+      u8 eType = 0;
+      Pgno iPtrPage = 0;
 
       releasePage(pPageMove);
 
       /* Move the page currently at pgnoRoot to pgnoMove. */
-      rc = sqlite3BtreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
       if( rc!=SQLITE_OK ){
         return rc;
       }
       rc = ptrmapGet(pBt, pgnoRoot, &eType, &iPtrPage);
-      if( rc!=SQLITE_OK || eType==PTRMAP_ROOTPAGE || eType==PTRMAP_FREEPAGE ){
+      if( eType==PTRMAP_ROOTPAGE || eType==PTRMAP_FREEPAGE ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }
+      if( rc!=SQLITE_OK ){
         releasePage(pRoot);
         return rc;
       }
       assert( eType!=PTRMAP_ROOTPAGE );
       assert( eType!=PTRMAP_FREEPAGE );
-      rc = sqlite3PagerWrite(pRoot->pDbPage);
-      if( rc!=SQLITE_OK ){
-        releasePage(pRoot);
-        return rc;
-      }
       rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
       releasePage(pRoot);
 
@@ -42490,7 +55053,7 @@ static int btreeCreateTable(Btree *p, int *piTable, int flags){
       if( rc!=SQLITE_OK ){
         return rc;
       }
-      rc = sqlite3BtreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
       if( rc!=SQLITE_OK ){
         return rc;
       }
@@ -42504,13 +55067,19 @@ static int btreeCreateTable(Btree *p, int *piTable, int flags){
     } 
 
     /* Update the pointer-map and meta-data with the new root-page number. */
-    rc = ptrmapPut(pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0);
+    ptrmapPut(pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0, &rc);
     if( rc ){
       releasePage(pRoot);
       return rc;
     }
+
+    /* When the new root page was allocated, page 1 was made writable in
+    ** order either to increase the database filesize, or to decrement the
+    ** freelist count.  Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
+    */
+    assert( sqlite3PagerIswriteable(pBt->pPage1->pDbPage) );
     rc = sqlite3BtreeUpdateMeta(p, 4, pgnoRoot);
-    if( rc ){
+    if( NEVER(rc) ){
       releasePage(pRoot);
       return rc;
     }
@@ -42521,15 +55090,20 @@ static int btreeCreateTable(Btree *p, int *piTable, int flags){
   }
 #endif
   assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
-  zeroPage(pRoot, flags | PTF_LEAF);
+  if( createTabFlags & BTREE_INTKEY ){
+    ptfFlags = PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF;
+  }else{
+    ptfFlags = PTF_ZERODATA | PTF_LEAF;
+  }
+  zeroPage(pRoot, ptfFlags);
   sqlite3PagerUnref(pRoot->pDbPage);
+  assert( (pBt->openFlags & BTREE_SINGLE)==0 || pgnoRoot==2 );
   *piTable = (int)pgnoRoot;
   return SQLITE_OK;
 }
 SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree *p, int *piTable, int flags){
   int rc;
   sqlite3BtreeEnter(p);
-  p->pBt->db = p->db;
   rc = btreeCreateTable(p, piTable, flags);
   sqlite3BtreeLeave(p);
   return rc;
@@ -42541,22 +55115,22 @@ SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree *p, int *piTable, int flags){
 */
 static int clearDatabasePage(
   BtShared *pBt,           /* The BTree that contains the table */
-  Pgno pgno,            /* Page number to clear */
-  int freePageFlag,     /* Deallocate page if true */
-  int *pnChange
+  Pgno pgno,               /* Page number to clear */
+  int freePageFlag,        /* Deallocate page if true */
+  int *pnChange            /* Add number of Cells freed to this counter */
 ){
-  MemPage *pPage = 0;
+  MemPage *pPage;
   int rc;
   unsigned char *pCell;
   int i;
 
   assert( sqlite3_mutex_held(pBt->mutex) );
-  if( pgno>pagerPagecount(pBt) ){
+  if( pgno>btreePagecount(pBt) ){
     return SQLITE_CORRUPT_BKPT;
   }
 
   rc = getAndInitPage(pBt, pgno, &pPage);
-  if( rc ) goto cleardatabasepage_out;
+  if( rc ) return rc;
   for(i=0; i<pPage->nCell; i++){
     pCell = findCell(pPage, i);
     if( !pPage->leaf ){
@@ -42574,7 +55148,7 @@ static int clearDatabasePage(
     *pnChange += pPage->nCell;
   }
   if( freePageFlag ){
-    rc = freePage(pPage);
+    freePage(pPage, &rc);
   }else if( (rc = sqlite3PagerWrite(pPage->pDbPage))==0 ){
     zeroPage(pPage, pPage->aData[0] | PTF_LEAF);
   }
@@ -42601,13 +55175,15 @@ SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree *p, int iTable, int *pnChange){
   int rc;
   BtShared *pBt = p->pBt;
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
   assert( p->inTrans==TRANS_WRITE );
-  if( (rc = checkReadLocks(p, iTable, 0, 1))!=SQLITE_OK ){
-    /* nothing to do */
-  }else if( SQLITE_OK!=(rc = saveAllCursors(pBt, iTable, 0)) ){
-    /* nothing to do */
-  }else{
+
+  rc = saveAllCursors(pBt, (Pgno)iTable, 0);
+
+  if( SQLITE_OK==rc ){
+    /* Invalidate all incrblob cursors open on table iTable (assuming iTable
+    ** is the root of a table b-tree - if it is not, the following call is
+    ** a no-op).  */
+    invalidateIncrblobCursors(p, 0, 1);
     rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
   }
   sqlite3BtreeLeave(p);
@@ -42647,12 +55223,15 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
   ** need to move another root-page to fill a gap left by the deleted
   ** root page. If an open cursor was using this page a problem would 
   ** occur.
+  **
+  ** This error is caught long before control reaches this point.
   */
-  if( pBt->pCursor ){
-    return SQLITE_LOCKED;
+  if( NEVER(pBt->pCursor) ){
+    sqlite3ConnectionBlocked(p->db, pBt->pCursor->pBtree->db);
+    return SQLITE_LOCKED_SHAREDCACHE;
   }
 
-  rc = sqlite3BtreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
+  rc = btreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
   if( rc ) return rc;
   rc = sqlite3BtreeClearTable(p, iTable, 0);
   if( rc ){
@@ -42664,22 +55243,18 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
 
   if( iTable>1 ){
 #ifdef SQLITE_OMIT_AUTOVACUUM
-    rc = freePage(pPage);
+    freePage(pPage, &rc);
     releasePage(pPage);
 #else
     if( pBt->autoVacuum ){
       Pgno maxRootPgno;
-      rc = sqlite3BtreeGetMeta(p, 4, &maxRootPgno);
-      if( rc!=SQLITE_OK ){
-        releasePage(pPage);
-        return rc;
-      }
+      sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &maxRootPgno);
 
       if( iTable==maxRootPgno ){
         /* If the table being dropped is the table with the largest root-page
         ** number in the database, put the root page on the free list. 
         */
-        rc = freePage(pPage);
+        freePage(pPage, &rc);
         releasePage(pPage);
         if( rc!=SQLITE_OK ){
           return rc;
@@ -42691,7 +55266,7 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
         */
         MemPage *pMove;
         releasePage(pPage);
-        rc = sqlite3BtreeGetPage(pBt, maxRootPgno, &pMove, 0);
+        rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
         if( rc!=SQLITE_OK ){
           return rc;
         }
@@ -42700,11 +55275,9 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
         if( rc!=SQLITE_OK ){
           return rc;
         }
-        rc = sqlite3BtreeGetPage(pBt, maxRootPgno, &pMove, 0);
-        if( rc!=SQLITE_OK ){
-          return rc;
-        }
-        rc = freePage(pMove);
+        pMove = 0;
+        rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
+        freePage(pMove, &rc);
         releasePage(pMove);
         if( rc!=SQLITE_OK ){
           return rc;
@@ -42718,22 +55291,23 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
       ** PENDING_BYTE_PAGE.
       */
       maxRootPgno--;
-      if( maxRootPgno==PENDING_BYTE_PAGE(pBt) ){
-        maxRootPgno--;
-      }
-      if( maxRootPgno==PTRMAP_PAGENO(pBt, maxRootPgno) ){
+      while( maxRootPgno==PENDING_BYTE_PAGE(pBt)
+             || PTRMAP_ISPAGE(pBt, maxRootPgno) ){
         maxRootPgno--;
       }
       assert( maxRootPgno!=PENDING_BYTE_PAGE(pBt) );
 
       rc = sqlite3BtreeUpdateMeta(p, 4, maxRootPgno);
     }else{
-      rc = freePage(pPage);
+      freePage(pPage, &rc);
       releasePage(pPage);
     }
 #endif
   }else{
-    /* If sqlite3BtreeDropTable was called on page 1. */
+    /* If sqlite3BtreeDropTable was called on page 1.
+    ** This really never should happen except in a corrupt
+    ** database. 
+    */
     zeroPage(pPage, PTF_INTKEY|PTF_LEAF );
     releasePage(pPage);
   }
@@ -42742,7 +55316,6 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
 SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree *p, int iTable, int *piMoved){
   int rc;
   sqlite3BtreeEnter(p);
-  p->pBt->db = p->db;
   rc = btreeDropTable(p, iTable, piMoved);
   sqlite3BtreeLeave(p);
   return rc;
@@ -42750,6 +55323,9 @@ SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree *p, int iTable, int *piMoved){
 
 
 /*
+** This function may only be called if the b-tree connection already
+** has a read or write transaction open on the database.
+**
 ** Read the meta-information out of a database file.  Meta[0]
 ** is the number of free pages currently in the database.  Meta[1]
 ** through meta[15] are available for use by higher layers.  Meta[0]
@@ -42759,65 +55335,26 @@ SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree *p, int iTable, int *piMoved){
 ** layer (and the SetCookie and ReadCookie opcodes) the number of
 ** free pages is not visible.  So Cookie[0] is the same as Meta[1].
 */
-SQLITE_PRIVATE int sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
-  DbPage *pDbPage = 0;
-  int rc;
-  unsigned char *pP1;
+SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
   BtShared *pBt = p->pBt;
 
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
-
-  /* Reading a meta-data value requires a read-lock on page 1 (and hence
-  ** the sqlite_master table. We grab this lock regardless of whether or
-  ** not the SQLITE_ReadUncommitted flag is set (the table rooted at page
-  ** 1 is treated as a special case by queryTableLock() and lockTable()).
-  */
-  rc = queryTableLock(p, 1, READ_LOCK);
-  if( rc!=SQLITE_OK ){
-    sqlite3BtreeLeave(p);
-    return rc;
-  }
-
+  assert( p->inTrans>TRANS_NONE );
+  assert( SQLITE_OK==querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK) );
+  assert( pBt->pPage1 );
   assert( idx>=0 && idx<=15 );
-  if( pBt->pPage1 ){
-    /* The b-tree is already holding a reference to page 1 of the database
-    ** file. In this case the required meta-data value can be read directly
-    ** from the page data of this reference. This is slightly faster than
-    ** requesting a new reference from the pager layer.
-    */
-    pP1 = (unsigned char *)pBt->pPage1->aData;
-  }else{
-    /* The b-tree does not have a reference to page 1 of the database file.
-    ** Obtain one from the pager layer.
-    */
-    rc = sqlite3PagerGet(pBt->pPager, 1, &pDbPage);
-    if( rc ){
-      sqlite3BtreeLeave(p);
-      return rc;
-    }
-    pP1 = (unsigned char *)sqlite3PagerGetData(pDbPage);
-  }
-  *pMeta = get4byte(&pP1[36 + idx*4]);
 
-  /* If the b-tree is not holding a reference to page 1, then one was 
-  ** requested from the pager layer in the above block. Release it now.
-  */
-  if( !pBt->pPage1 ){
-    sqlite3PagerUnref(pDbPage);
-  }
+  *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);
 
-  /* If autovacuumed is disabled in this build but we are trying to 
-  ** access an autovacuumed database, then make the database readonly. 
-  */
+  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
+  ** database, mark the database as read-only.  */
 #ifdef SQLITE_OMIT_AUTOVACUUM
-  if( idx==4 && *pMeta>0 ) pBt->readOnly = 1;
+  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
+    pBt->btsFlags |= BTS_READ_ONLY;
+  }
 #endif
 
-  /* Grab the read-lock on page 1. */
-  rc = lockTable(p, 1, READ_LOCK);
   sqlite3BtreeLeave(p);
-  return rc;
 }
 
 /*
@@ -42830,7 +55367,6 @@ SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
   int rc;
   assert( idx>=1 && idx<=15 );
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
   assert( p->inTrans==TRANS_WRITE );
   assert( pBt->pPage1!=0 );
   pP1 = pBt->pPage1->aData;
@@ -42838,7 +55374,7 @@ SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
   if( rc==SQLITE_OK ){
     put4byte(&pP1[36 + idx*4], iMeta);
 #ifndef SQLITE_OMIT_AUTOVACUUM
-    if( idx==7 ){
+    if( idx==BTREE_INCR_VACUUM ){
       assert( pBt->autoVacuum || iMeta==0 );
       assert( iMeta==0 || iMeta==1 );
       pBt->incrVacuum = (u8)iMeta;
@@ -42849,23 +55385,80 @@ SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
   return rc;
 }
 
+#ifndef SQLITE_OMIT_BTREECOUNT
 /*
-** Return the flag byte at the beginning of the page that the cursor
-** is currently pointing to.
+** The first argument, pCur, is a cursor opened on some b-tree. Count the
+** number of entries in the b-tree and write the result to *pnEntry.
+**
+** SQLITE_OK is returned if the operation is successfully executed. 
+** Otherwise, if an error is encountered (i.e. an IO error or database
+** corruption) an SQLite error code is returned.
 */
-SQLITE_PRIVATE int sqlite3BtreeFlags(BtCursor *pCur){
-  /* TODO: What about CURSOR_REQUIRESEEK state? Probably need to call
-  ** restoreCursorPosition() here.
-  */
-  MemPage *pPage;
-  restoreCursorPosition(pCur);
-  pPage = pCur->apPage[pCur->iPage];
-  assert( cursorHoldsMutex(pCur) );
-  assert( pPage!=0 );
-  assert( pPage->pBt==pCur->pBt );
-  return pPage->aData[pPage->hdrOffset];
-}
+SQLITE_PRIVATE int sqlite3BtreeCount(BtCursor *pCur, i64 *pnEntry){
+  i64 nEntry = 0;                      /* Value to return in *pnEntry */
+  int rc;                              /* Return code */
 
+  if( pCur->pgnoRoot==0 ){
+    *pnEntry = 0;
+    return SQLITE_OK;
+  }
+  rc = moveToRoot(pCur);
+
+  /* Unless an error occurs, the following loop runs one iteration for each
+  ** page in the B-Tree structure (not including overflow pages). 
+  */
+  while( rc==SQLITE_OK ){
+    int iIdx;                          /* Index of child node in parent */
+    MemPage *pPage;                    /* Current page of the b-tree */
+
+    /* If this is a leaf page or the tree is not an int-key tree, then 
+    ** this page contains countable entries. Increment the entry counter
+    ** accordingly.
+    */
+    pPage = pCur->apPage[pCur->iPage];
+    if( pPage->leaf || !pPage->intKey ){
+      nEntry += pPage->nCell;
+    }
+
+    /* pPage is a leaf node. This loop navigates the cursor so that it 
+    ** points to the first interior cell that it points to the parent of
+    ** the next page in the tree that has not yet been visited. The
+    ** pCur->aiIdx[pCur->iPage] value is set to the index of the parent cell
+    ** of the page, or to the number of cells in the page if the next page
+    ** to visit is the right-child of its parent.
+    **
+    ** If all pages in the tree have been visited, return SQLITE_OK to the
+    ** caller.
+    */
+    if( pPage->leaf ){
+      do {
+        if( pCur->iPage==0 ){
+          /* All pages of the b-tree have been visited. Return successfully. */
+          *pnEntry = nEntry;
+          return SQLITE_OK;
+        }
+        moveToParent(pCur);
+      }while ( pCur->aiIdx[pCur->iPage]>=pCur->apPage[pCur->iPage]->nCell );
+
+      pCur->aiIdx[pCur->iPage]++;
+      pPage = pCur->apPage[pCur->iPage];
+    }
+
+    /* Descend to the child node of the cell that the cursor currently 
+    ** points at. This is the right-child if (iIdx==pPage->nCell).
+    */
+    iIdx = pCur->aiIdx[pCur->iPage];
+    if( iIdx==pPage->nCell ){
+      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
+    }else{
+      rc = moveToChild(pCur, get4byte(findCell(pPage, iIdx)));
+    }
+  }
+
+  /* An error has occurred. Return an error code. */
+  return rc;
+}
+#endif
 
 /*
 ** Return the pager associated with a BTree.  This routine is used for
@@ -42905,6 +55498,25 @@ static void checkAppendMsg(
 #endif /* SQLITE_OMIT_INTEGRITY_CHECK */
 
 #ifndef SQLITE_OMIT_INTEGRITY_CHECK
+
+/*
+** Return non-zero if the bit in the IntegrityCk.aPgRef[] array that
+** corresponds to page iPg is already set.
+*/
+static int getPageReferenced(IntegrityCk *pCheck, Pgno iPg){
+  assert( iPg<=pCheck->nPage && sizeof(pCheck->aPgRef[0])==1 );
+  return (pCheck->aPgRef[iPg/8] & (1 << (iPg & 0x07)));
+}
+
+/*
+** Set the bit in the IntegrityCk.aPgRef[] array that corresponds to page iPg.
+*/
+static void setPageReferenced(IntegrityCk *pCheck, Pgno iPg){
+  assert( iPg<=pCheck->nPage && sizeof(pCheck->aPgRef[0])==1 );
+  pCheck->aPgRef[iPg/8] |= (1 << (iPg & 0x07));
+}
+
+
 /*
 ** Add 1 to the reference count for page iPage.  If this is the second
 ** reference to the page, add an error message to pCheck->zErrMsg.
@@ -42919,11 +55531,12 @@ static int checkRef(IntegrityCk *pCheck, Pgno iPage, char *zContext){
     checkAppendMsg(pCheck, zContext, "invalid page number %d", iPage);
     return 1;
   }
-  if( pCheck->anRef[iPage]==1 ){
+  if( getPageReferenced(pCheck, iPage) ){
     checkAppendMsg(pCheck, zContext, "2nd reference to page %d", iPage);
     return 1;
   }
-  return  (pCheck->anRef[iPage]++)>1;
+  setPageReferenced(pCheck, iPage);
+  return 0;
 }
 
 #ifndef SQLITE_OMIT_AUTOVACUUM
@@ -42945,7 +55558,7 @@ static void checkPtrmap(
 
   rc = ptrmapGet(pCheck->pBt, iChild, &ePtrmapType, &iPtrmapParent);
   if( rc!=SQLITE_OK ){
-    if( rc==SQLITE_NOMEM ) pCheck->mallocFailed = 1;
+    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ) pCheck->mallocFailed = 1;
     checkAppendMsg(pCheck, zContext, "Failed to read ptrmap key=%d", iChild);
     return;
   }
@@ -42994,7 +55607,7 @@ static void checkList(
         checkPtrmap(pCheck, iPage, PTRMAP_FREEPAGE, 0, zContext);
       }
 #endif
-      if( n>pCheck->pBt->usableSize/4-2 ){
+      if( n>(int)pCheck->pBt->usableSize/4-2 ){
         checkAppendMsg(pCheck, zContext,
            "freelist leaf count too big on page %d", iPage);
         N--;
@@ -43051,7 +55664,9 @@ static void checkList(
 static int checkTreePage(
   IntegrityCk *pCheck,  /* Context for the sanity check */
   int iPage,            /* Page number of the page to check */
-  char *zParentContext  /* Parent context */
+  char *zParentContext, /* Parent context */
+  i64 *pnParentMinKey, 
+  i64 *pnParentMaxKey
 ){
   MemPage *pPage;
   int i, rc, depth, d2, pgno, cnt;
@@ -43062,6 +55677,8 @@ static int checkTreePage(
   int usableSize;
   char zContext[100];
   char *hit = 0;
+  i64 nMinKey = 0;
+  i64 nMaxKey = 0;
 
   sqlite3_snprintf(sizeof(zContext), zContext, "Page %d: ", iPage);
 
@@ -43071,16 +55688,19 @@ static int checkTreePage(
   usableSize = pBt->usableSize;
   if( iPage==0 ) return 0;
   if( checkRef(pCheck, iPage, zParentContext) ) return 0;
-  if( (rc = sqlite3BtreeGetPage(pBt, (Pgno)iPage, &pPage, 0))!=0 ){
-    if( rc==SQLITE_NOMEM ) pCheck->mallocFailed = 1;
+  if( (rc = btreeGetPage(pBt, (Pgno)iPage, &pPage, 0))!=0 ){
     checkAppendMsg(pCheck, zContext,
        "unable to get the page. error code=%d", rc);
     return 0;
   }
-  if( (rc = sqlite3BtreeInitPage(pPage))!=0 ){
+
+  /* Clear MemPage.isInit to make sure the corruption detection code in
+  ** btreeInitPage() is executed.  */
+  pPage->isInit = 0;
+  if( (rc = btreeInitPage(pPage))!=0 ){
     assert( rc==SQLITE_CORRUPT );  /* The only possible error from InitPage */
     checkAppendMsg(pCheck, zContext, 
-                   "sqlite3BtreeInitPage() returns error code %d", rc);
+                   "btreeInitPage() returns error code %d", rc);
     releasePage(pPage);
     return 0;
   }
@@ -43098,11 +55718,23 @@ static int checkTreePage(
     sqlite3_snprintf(sizeof(zContext), zContext,
              "On tree page %d cell %d: ", iPage, i);
     pCell = findCell(pPage,i);
-    sqlite3BtreeParseCellPtr(pPage, pCell, &info);
+    btreeParseCellPtr(pPage, pCell, &info);
     sz = info.nData;
     if( !pPage->intKey ) sz += (int)info.nKey;
+    /* For intKey pages, check that the keys are in order.
+    */
+    else if( i==0 ) nMinKey = nMaxKey = info.nKey;
+    else{
+      if( info.nKey <= nMaxKey ){
+        checkAppendMsg(pCheck, zContext, 
+            "Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
+      }
+      nMaxKey = info.nKey;
+    }
     assert( sz==info.nPayload );
-    if( sz>info.nLocal ){
+    if( (sz>info.nLocal) 
+     && (&pCell[info.iOverflow]<=&pPage->aData[pBt->usableSize])
+    ){
       int nPage = (sz - info.nLocal + usableSize - 5)/(usableSize - 4);
       Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
 #ifndef SQLITE_OMIT_AUTOVACUUM
@@ -43122,25 +55754,62 @@ static int checkTreePage(
         checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
       }
 #endif
-      d2 = checkTreePage(pCheck, pgno, zContext);
+      d2 = checkTreePage(pCheck, pgno, zContext, &nMinKey, i==0 ? NULL : &nMaxKey);
       if( i>0 && d2!=depth ){
         checkAppendMsg(pCheck, zContext, "Child page depth differs");
       }
       depth = d2;
     }
   }
+
   if( !pPage->leaf ){
     pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
     sqlite3_snprintf(sizeof(zContext), zContext, 
                      "On page %d at right child: ", iPage);
 #ifndef SQLITE_OMIT_AUTOVACUUM
     if( pBt->autoVacuum ){
-      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, 0);
+      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
     }
 #endif
-    checkTreePage(pCheck, pgno, zContext);
+    checkTreePage(pCheck, pgno, zContext, NULL, !pPage->nCell ? NULL : &nMaxKey);
   }
  
+  /* For intKey leaf pages, check that the min/max keys are in order
+  ** with any left/parent/right pages.
+  */
+  if( pPage->leaf && pPage->intKey ){
+    /* if we are a left child page */
+    if( pnParentMinKey ){
+      /* if we are the left most child page */
+      if( !pnParentMaxKey ){
+        if( nMaxKey > *pnParentMinKey ){
+          checkAppendMsg(pCheck, zContext, 
+              "Rowid %lld out of order (max larger than parent min of %lld)",
+              nMaxKey, *pnParentMinKey);
+        }
+      }else{
+        if( nMinKey <= *pnParentMinKey ){
+          checkAppendMsg(pCheck, zContext, 
+              "Rowid %lld out of order (min less than parent min of %lld)",
+              nMinKey, *pnParentMinKey);
+        }
+        if( nMaxKey > *pnParentMaxKey ){
+          checkAppendMsg(pCheck, zContext, 
+              "Rowid %lld out of order (max larger than parent max of %lld)",
+              nMaxKey, *pnParentMaxKey);
+        }
+        *pnParentMinKey = nMaxKey;
+      }
+    /* else if we're a right child page */
+    } else if( pnParentMaxKey ){
+      if( nMinKey <= *pnParentMaxKey ){
+        checkAppendMsg(pCheck, zContext, 
+            "Rowid %lld out of order (min less than parent max of %lld)",
+            nMinKey, *pnParentMaxKey);
+      }
+    }
+  }
+
   /* Check for complete coverage of the page
   */
   data = pPage->aData;
@@ -43149,41 +55818,37 @@ static int checkTreePage(
   if( hit==0 ){
     pCheck->mallocFailed = 1;
   }else{
-    u16 contentOffset = get2byte(&data[hdr+5]);
-    if (contentOffset > usableSize) {
-      checkAppendMsg(pCheck, 0, 
-                     "Corruption detected in header on page %d",iPage,0);
-      goto check_page_abort;
-    }
+    int contentOffset = get2byteNotZero(&data[hdr+5]);
+    assert( contentOffset<=usableSize );  /* Enforced by btreeInitPage() */
     memset(hit+contentOffset, 0, usableSize-contentOffset);
     memset(hit, 1, contentOffset);
     nCell = get2byte(&data[hdr+3]);
     cellStart = hdr + 12 - 4*pPage->leaf;
     for(i=0; i<nCell; i++){
       int pc = get2byte(&data[cellStart+i*2]);
-      u16 size = 1024;
+      u32 size = 65536;
       int j;
-      if( pc<=usableSize ){
+      if( pc<=usableSize-4 ){
         size = cellSizePtr(pPage, &data[pc]);
       }
-      if( (pc+size-1)>=usableSize || pc<0 ){
+      if( (int)(pc+size-1)>=usableSize ){
         checkAppendMsg(pCheck, 0, 
-            "Corruption detected in cell %d on page %d",i,iPage,0);
+            "Corruption detected in cell %d on page %d",i,iPage);
       }else{
         for(j=pc+size-1; j>=pc; j--) hit[j]++;
       }
     }
-    for(cnt=0, i=get2byte(&data[hdr+1]); i>0 && i<usableSize && cnt<10000; 
-           cnt++){
-      int size = get2byte(&data[i+2]);
-      int j;
-      if( (i+size-1)>=usableSize || i<0 ){
-        checkAppendMsg(pCheck, 0,  
-            "Corruption detected in cell %d on page %d",i,iPage,0);
-      }else{
-        for(j=i+size-1; j>=i; j--) hit[j]++;
-      }
-      i = get2byte(&data[i]);
+    i = get2byte(&data[hdr+1]);
+    while( i>0 ){
+      int size, j;
+      assert( i<=usableSize-4 );     /* Enforced by btreeInitPage() */
+      size = get2byte(&data[i+2]);
+      assert( i+size<=usableSize );  /* Enforced by btreeInitPage() */
+      for(j=i+size-1; j>=i; j--) hit[j]++;
+      j = get2byte(&data[i]);
+      assert( j==0 || j>i+size );  /* Enforced by btreeInitPage() */
+      assert( j<=usableSize-4 );   /* Enforced by btreeInitPage() */
+      i = j;
     }
     for(i=cnt=0; i<usableSize; i++){
       if( hit[i]==0 ){
@@ -43196,13 +55861,11 @@ static int checkTreePage(
     }
     if( cnt!=data[hdr+7] ){
       checkAppendMsg(pCheck, 0, 
-          "Fragmented space is %d byte reported as %d on page %d",
+          "Fragmentation of %d bytes reported as %d on page %d",
           cnt, data[hdr+7], iPage);
     }
   }
-check_page_abort:
-  if (hit) sqlite3PageFree(hit);
-
+  sqlite3PageFree(hit);
   releasePage(pPage);
   return depth+1;
 }
@@ -43214,6 +55877,9 @@ check_page_abort:
 ** an array of pages numbers were each page number is the root page of
 ** a table.  nRoot is the number of entries in aRoot.
 **
+** A read-only or read-write transaction must be opened before calling
+** this function.
+**
 ** Write the number of error seen in *pnErr.  Except for some memory
 ** allocation errors,  an error message held in memory obtained from
 ** malloc is returned if *pnErr is non-zero.  If *pnErr==0 then NULL is
@@ -43233,38 +55899,30 @@ SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(
   char zErr[100];
 
   sqlite3BtreeEnter(p);
-  pBt->db = p->db;
+  assert( p->inTrans>TRANS_NONE && pBt->inTransaction>TRANS_NONE );
   nRef = sqlite3PagerRefcount(pBt->pPager);
-  if( lockBtreeWithRetry(p)!=SQLITE_OK ){
-    *pnErr = 1;
-    sqlite3BtreeLeave(p);
-    return sqlite3DbStrDup(0, "cannot acquire a read lock on the database");
-  }
   sCheck.pBt = pBt;
   sCheck.pPager = pBt->pPager;
-  sCheck.nPage = pagerPagecount(sCheck.pBt);
+  sCheck.nPage = btreePagecount(sCheck.pBt);
   sCheck.mxErr = mxErr;
   sCheck.nErr = 0;
   sCheck.mallocFailed = 0;
   *pnErr = 0;
   if( sCheck.nPage==0 ){
-    unlockBtreeIfUnused(pBt);
     sqlite3BtreeLeave(p);
     return 0;
   }
-  sCheck.anRef = sqlite3Malloc( (sCheck.nPage+1)*sizeof(sCheck.anRef[0]) );
-  if( !sCheck.anRef ){
-    unlockBtreeIfUnused(pBt);
+
+  sCheck.aPgRef = sqlite3MallocZero((sCheck.nPage / 8)+ 1);
+  if( !sCheck.aPgRef ){
     *pnErr = 1;
     sqlite3BtreeLeave(p);
     return 0;
   }
-  for(i=0; i<=sCheck.nPage; i++){ sCheck.anRef[i] = 0; }
   i = PENDING_BYTE_PAGE(pBt);
-  if( i<=sCheck.nPage ){
-    sCheck.anRef[i] = 1;
-  }
+  if( i<=sCheck.nPage ) setPageReferenced(&sCheck, i);
   sqlite3StrAccumInit(&sCheck.errMsg, zErr, sizeof(zErr), 20000);
+  sCheck.errMsg.useMalloc = 2;
 
   /* Check the integrity of the freelist
   */
@@ -43280,25 +55938,25 @@ SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(
       checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0, 0);
     }
 #endif
-    checkTreePage(&sCheck, aRoot[i], "List of tree roots: ");
+    checkTreePage(&sCheck, aRoot[i], "List of tree roots: ", NULL, NULL);
   }
 
   /* Make sure every page in the file is referenced
   */
   for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
 #ifdef SQLITE_OMIT_AUTOVACUUM
-    if( sCheck.anRef[i]==0 ){
+    if( getPageReferenced(&sCheck, i)==0 ){
       checkAppendMsg(&sCheck, 0, "Page %d is never used", i);
     }
 #else
     /* If the database supports auto-vacuum, make sure no tables contain
     ** references to pointer-map pages.
     */
-    if( sCheck.anRef[i]==0 && 
+    if( getPageReferenced(&sCheck, i)==0 && 
        (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
       checkAppendMsg(&sCheck, 0, "Page %d is never used", i);
     }
-    if( sCheck.anRef[i]!=0 && 
+    if( getPageReferenced(&sCheck, i)!=0 && 
        (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
       checkAppendMsg(&sCheck, 0, "Pointer map page %d is referenced", i);
     }
@@ -43309,7 +55967,6 @@ SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(
   ** This is an internal consistency check; an integrity check
   ** of the integrity check.
   */
-  unlockBtreeIfUnused(pBt);
   if( NEVER(nRef != sqlite3PagerRefcount(pBt->pPager)) ){
     checkAppendMsg(&sCheck, 0, 
       "Outstanding page count goes from %d to %d during this analysis",
@@ -43320,7 +55977,7 @@ SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(
   /* Clean  up and report errors.
   */
   sqlite3BtreeLeave(p);
-  sqlite3_free(sCheck.anRef);
+  sqlite3_free(sCheck.aPgRef);
   if( sCheck.mallocFailed ){
     sqlite3StrAccumReset(&sCheck.errMsg);
     *pnErr = sCheck.nErr+1;
@@ -43333,25 +55990,15 @@ SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(
 #endif /* SQLITE_OMIT_INTEGRITY_CHECK */
 
 /*
-** Return the full pathname of the underlying database file.
+** Return the full pathname of the underlying database file.  Return
+** an empty string if the database is in-memory or a TEMP database.
 **
 ** The pager filename is invariant as long as the pager is
 ** open so it is safe to access without the BtShared mutex.
 */
 SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *p){
   assert( p->pBt->pPager!=0 );
-  return sqlite3PagerFilename(p->pBt->pPager);
-}
-
-/*
-** Return the pathname of the directory that contains the database file.
-**
-** The pager directory name is invariant as long as the pager is
-** open so it is safe to access without the BtShared mutex.
-*/
-SQLITE_PRIVATE const char *sqlite3BtreeGetDirname(Btree *p){
-  assert( p->pBt->pPager!=0 );
-  return sqlite3PagerDirname(p->pBt->pPager);
+  return sqlite3PagerFilename(p->pBt->pPager, 1);
 }
 
 /*
@@ -43367,221 +56014,6 @@ SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *p){
   return sqlite3PagerJournalname(p->pBt->pPager);
 }
 
-#ifndef SQLITE_OMIT_VACUUM
-/*
-** Copy the complete content of pBtFrom into pBtTo.  A transaction
-** must be active for both files.
-**
-** The size of file pTo may be reduced by this operation.
-** If anything goes wrong, the transaction on pTo is rolled back. 
-**
-** If successful, CommitPhaseOne() may be called on pTo before returning. 
-** The caller should finish committing the transaction on pTo by calling
-** sqlite3BtreeCommit().
-*/
-static int btreeCopyFile(Btree *pTo, Btree *pFrom){
-  int rc = SQLITE_OK;
-  Pgno i;
-
-  Pgno nFromPage;     /* Number of pages in pFrom */
-  Pgno nToPage;       /* Number of pages in pTo */
-  Pgno nNewPage;      /* Number of pages in pTo after the copy */
-
-  Pgno iSkip;         /* Pending byte page in pTo */
-  int nToPageSize;    /* Page size of pTo in bytes */
-  int nFromPageSize;  /* Page size of pFrom in bytes */
-
-  BtShared *pBtTo = pTo->pBt;
-  BtShared *pBtFrom = pFrom->pBt;
-  pBtTo->db = pTo->db;
-  pBtFrom->db = pFrom->db;
-
-  nToPageSize = pBtTo->pageSize;
-  nFromPageSize = pBtFrom->pageSize;
-
-  assert( pTo->inTrans==TRANS_WRITE );
-  assert( pFrom->inTrans==TRANS_WRITE );
-  if( NEVER(pBtTo->pCursor) ){
-    return SQLITE_BUSY;
-  }
-
-  nToPage = pagerPagecount(pBtTo);
-  nFromPage = pagerPagecount(pBtFrom);
-  iSkip = PENDING_BYTE_PAGE(pBtTo);
-
-  /* Variable nNewPage is the number of pages required to store the
-  ** contents of pFrom using the current page-size of pTo.
-  */
-  nNewPage = (Pgno)
-     (((i64)nFromPage*(i64)nFromPageSize+(i64)nToPageSize-1)/(i64)nToPageSize);
-
-  for(i=1; rc==SQLITE_OK && (i<=nToPage || i<=nNewPage); i++){
-
-    /* Journal the original page.
-    **
-    ** iSkip is the page number of the locking page (PENDING_BYTE_PAGE)
-    ** in database *pTo (before the copy). This page is never written 
-    ** into the journal file. Unless i==iSkip or the page was not
-    ** present in pTo before the copy operation, journal page i from pTo.
-    */
-    if( i!=iSkip && i<=nToPage ){
-      DbPage *pDbPage = 0;
-      rc = sqlite3PagerGet(pBtTo->pPager, i, &pDbPage);
-      if( rc==SQLITE_OK ){
-        rc = sqlite3PagerWrite(pDbPage);
-        if( rc==SQLITE_OK && i>nFromPage ){
-          /* Yeah.  It seems wierd to call DontWrite() right after Write(). But
-          ** that is because the names of those procedures do not exactly 
-          ** represent what they do.  Write() really means "put this page in the
-          ** rollback journal and mark it as dirty so that it will be written
-          ** to the database file later."  DontWrite() undoes the second part of
-          ** that and prevents the page from being written to the database. The
-          ** page is still on the rollback journal, though.  And that is the 
-          ** whole point of this block: to put pages on the rollback journal. 
-          */
-          rc = sqlite3PagerDontWrite(pDbPage);
-        }
-        sqlite3PagerUnref(pDbPage);
-      }
-    }
-
-    /* Overwrite the data in page i of the target database */
-    if( rc==SQLITE_OK && i!=iSkip && i<=nNewPage ){
-
-      DbPage *pToPage = 0;
-      sqlite3_int64 iOff;
-
-      rc = sqlite3PagerGet(pBtTo->pPager, i, &pToPage);
-      if( rc==SQLITE_OK ){
-        rc = sqlite3PagerWrite(pToPage);
-      }
-
-      for(
-        iOff=(i-1)*nToPageSize; 
-        rc==SQLITE_OK && iOff<i*nToPageSize; 
-        iOff += nFromPageSize
-      ){
-        DbPage *pFromPage = 0;
-        Pgno iFrom = (Pgno)(iOff/nFromPageSize)+1;
-
-        if( iFrom==PENDING_BYTE_PAGE(pBtFrom) ){
-          continue;
-        }
-
-        rc = sqlite3PagerGet(pBtFrom->pPager, iFrom, &pFromPage);
-        if( rc==SQLITE_OK ){
-          char *zTo = sqlite3PagerGetData(pToPage);
-          char *zFrom = sqlite3PagerGetData(pFromPage);
-          int nCopy;
-
-          if( nFromPageSize>=nToPageSize ){
-            zFrom += ((i-1)*nToPageSize - ((iFrom-1)*nFromPageSize));
-            nCopy = nToPageSize;
-          }else{
-            zTo += (((iFrom-1)*nFromPageSize) - (i-1)*nToPageSize);
-            nCopy = nFromPageSize;
-          }
-
-          memcpy(zTo, zFrom, nCopy);
-          sqlite3PagerUnref(pFromPage);
-        }
-      }
-
-      if( pToPage ){
-        MemPage *p = (MemPage *)sqlite3PagerGetExtra(pToPage);
-        p->isInit = 0;
-        sqlite3PagerUnref(pToPage);
-      }
-    }
-  }
-
-  /* If things have worked so far, the database file may need to be 
-  ** truncated. The complex part is that it may need to be truncated to
-  ** a size that is not an integer multiple of nToPageSize - the current
-  ** page size used by the pager associated with B-Tree pTo.
-  **
-  ** For example, say the page-size of pTo is 2048 bytes and the original 
-  ** number of pages is 5 (10 KB file). If pFrom has a page size of 1024 
-  ** bytes and 9 pages, then the file needs to be truncated to 9KB.
-  */
-  if( rc==SQLITE_OK ){
-    sqlite3_file *pFile = sqlite3PagerFile(pBtTo->pPager);
-    i64 iSize = (i64)nFromPageSize * (i64)nFromPage;
-    i64 iNow = (i64)((nToPage>nNewPage)?nToPage:nNewPage) * (i64)nToPageSize; 
-    i64 iPending = ((i64)PENDING_BYTE_PAGE(pBtTo)-1) *(i64)nToPageSize;
-
-    assert( iSize<=iNow );
-
-    /* Commit phase one syncs the journal file associated with pTo 
-    ** containing the original data. It does not sync the database file
-    ** itself. After doing this it is safe to use OsTruncate() and other
-    ** file APIs on the database file directly.
-    */
-    pBtTo->db = pTo->db;
-    rc = sqlite3PagerCommitPhaseOne(pBtTo->pPager, 0, 1);
-    if( iSize<iNow && rc==SQLITE_OK ){
-      rc = sqlite3OsTruncate(pFile, iSize);
-    }
-
-    /* The loop that copied data from database pFrom to pTo did not
-    ** populate the locking page of database pTo. If the page-size of
-    ** pFrom is smaller than that of pTo, this means some data will
-    ** not have been copied. 
-    **
-    ** This block copies the missing data from database pFrom to pTo 
-    ** using file APIs. This is safe because at this point we know that
-    ** all of the original data from pTo has been synced into the 
-    ** journal file. At this point it would be safe to do anything at
-    ** all to the database file except truncate it to zero bytes.
-    */
-    if( rc==SQLITE_OK && nFromPageSize<nToPageSize && iSize>iPending){
-      i64 iOff;
-      for(
-        iOff=iPending; 
-        rc==SQLITE_OK && iOff<(iPending+nToPageSize); 
-        iOff += nFromPageSize
-      ){
-        DbPage *pFromPage = 0;
-        Pgno iFrom = (Pgno)(iOff/nFromPageSize)+1;
-
-        if( iFrom==PENDING_BYTE_PAGE(pBtFrom) || iFrom>nFromPage ){
-          continue;
-        }
-
-        rc = sqlite3PagerGet(pBtFrom->pPager, iFrom, &pFromPage);
-        if( rc==SQLITE_OK ){
-          char *zFrom = sqlite3PagerGetData(pFromPage);
-          rc = sqlite3OsWrite(pFile, zFrom, nFromPageSize, iOff);
-          sqlite3PagerUnref(pFromPage);
-        }
-      }
-    }
-  }
-
-  /* Sync the database file */
-  if( rc==SQLITE_OK ){
-    rc = sqlite3PagerSync(pBtTo->pPager);
-  }
-  if( rc==SQLITE_OK ){
-    pBtTo->pageSizeFixed = 0;
-  }else{
-    sqlite3BtreeRollback(pTo);
-  }
-
-  return rc;
-}
-SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
-  int rc;
-  sqlite3BtreeEnter(pTo);
-  sqlite3BtreeEnter(pFrom);
-  rc = btreeCopyFile(pTo, pFrom);
-  sqlite3BtreeLeave(pFrom);
-  sqlite3BtreeLeave(pTo);
-  return rc;
-}
-
-#endif /* SQLITE_OMIT_VACUUM */
-
 /*
 ** Return non-zero if a transaction is active.
 */
@@ -43590,13 +56022,30 @@ SQLITE_PRIVATE int sqlite3BtreeIsInTrans(Btree *p){
   return (p && (p->inTrans==TRANS_WRITE));
 }
 
+#ifndef SQLITE_OMIT_WAL
 /*
-** Return non-zero if a statement transaction is active.
+** Run a checkpoint on the Btree passed as the first argument.
+**
+** Return SQLITE_LOCKED if this or any other connection has an open 
+** transaction on the shared-cache the argument Btree is connected to.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
 */
-SQLITE_PRIVATE int sqlite3BtreeIsInStmt(Btree *p){
-  assert( sqlite3BtreeHoldsMutex(p) );
-  return ALWAYS(p->pBt) && p->pBt->inStmt;
+SQLITE_PRIVATE int sqlite3BtreeCheckpoint(Btree *p, int eMode, int *pnLog, int *pnCkpt){
+  int rc = SQLITE_OK;
+  if( p ){
+    BtShared *pBt = p->pBt;
+    sqlite3BtreeEnter(p);
+    if( pBt->inTransaction!=TRANS_NONE ){
+      rc = SQLITE_LOCKED;
+    }else{
+      rc = sqlite3PagerCheckpoint(pBt->pPager, eMode, pnLog, pnCkpt);
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
 }
+#endif
 
 /*
 ** Return non-zero if a read (or write) transaction is active.
@@ -43607,6 +56056,12 @@ SQLITE_PRIVATE int sqlite3BtreeIsInReadTrans(Btree *p){
   return p->inTrans!=TRANS_NONE;
 }
 
+SQLITE_PRIVATE int sqlite3BtreeIsInBackup(Btree *p){
+  assert( p );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  return p->nBackup!=0;
+}
+
 /*
 ** This function returns a pointer to a blob of memory associated with
 ** a single shared-btree. The memory is used by client code for its own
@@ -43624,14 +56079,14 @@ SQLITE_PRIVATE int sqlite3BtreeIsInReadTrans(Btree *p){
 **
 ** Just before the shared-btree is closed, the function passed as the 
 ** xFree argument when the memory allocation was made is invoked on the 
-** blob of allocated memory. This function should not call sqlite3_free()
+** blob of allocated memory. The xFree function should not call sqlite3_free()
 ** on the memory, the btree layer does that.
 */
 SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
   BtShared *pBt = p->pBt;
   sqlite3BtreeEnter(p);
   if( !pBt->pSchema && nBytes ){
-    pBt->pSchema = sqlite3MallocZero(nBytes);
+    pBt->pSchema = sqlite3DbMallocZero(0, nBytes);
     pBt->xFreeSchema = xFree;
   }
   sqlite3BtreeLeave(p);
@@ -43639,14 +56094,16 @@ SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void
 }
 
 /*
-** Return true if another user of the same shared btree as the argument
-** handle holds an exclusive lock on the sqlite_master table.
+** Return SQLITE_LOCKED_SHAREDCACHE if another user of the same shared 
+** btree as the argument handle holds an exclusive lock on the 
+** sqlite_master table. Otherwise SQLITE_OK.
 */
 SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *p){
   int rc;
   assert( sqlite3_mutex_held(p->db->mutex) );
   sqlite3BtreeEnter(p);
-  rc = (queryTableLock(p, MASTER_ROOT, READ_LOCK)!=SQLITE_OK);
+  rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
+  assert( rc==SQLITE_OK || rc==SQLITE_LOCKED_SHAREDCACHE );
   sqlite3BtreeLeave(p);
   return rc;
 }
@@ -43660,14 +56117,16 @@ SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *p){
 */
 SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *p, int iTab, u8 isWriteLock){
   int rc = SQLITE_OK;
+  assert( p->inTrans!=TRANS_NONE );
   if( p->sharable ){
     u8 lockType = READ_LOCK + isWriteLock;
     assert( READ_LOCK+1==WRITE_LOCK );
     assert( isWriteLock==0 || isWriteLock==1 );
+
     sqlite3BtreeEnter(p);
-    rc = queryTableLock(p, iTab, lockType);
+    rc = querySharedCacheTableLock(p, iTab, lockType);
     if( rc==SQLITE_OK ){
-      rc = lockTable(p, iTab, lockType);
+      rc = setSharedCacheTableLock(p, iTab, lockType);
     }
     sqlite3BtreeLeave(p);
   }
@@ -43680,38 +56139,44 @@ SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *p, int iTab, u8 isWriteLock){
 ** Argument pCsr must be a cursor opened for writing on an 
 ** INTKEY table currently pointing at a valid table entry. 
 ** This function modifies the data stored as part of that entry.
-** Only the data content may only be modified, it is not possible
-** to change the length of the data stored.
+**
+** Only the data content may only be modified, it is not possible to 
+** change the length of the data stored. If this function is called with
+** parameters that attempt to write past the end of the existing data,
+** no modifications are made and SQLITE_CORRUPT is returned.
 */
 SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
+  int rc;
   assert( cursorHoldsMutex(pCsr) );
   assert( sqlite3_mutex_held(pCsr->pBtree->db->mutex) );
-  assert(pCsr->isIncrblobHandle);
+  assert( pCsr->isIncrblobHandle );
 
-  restoreCursorPosition(pCsr);
+  rc = restoreCursorPosition(pCsr);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
   assert( pCsr->eState!=CURSOR_REQUIRESEEK );
   if( pCsr->eState!=CURSOR_VALID ){
     return SQLITE_ABORT;
   }
 
-  /* Check some preconditions: 
+  /* Check some assumptions: 
   **   (a) the cursor is open for writing,
-  **   (b) there is no read-lock on the table being modified and
-  **   (c) the cursor points at a valid row of an intKey table.
+  **   (b) there is a read/write transaction open,
+  **   (c) the connection holds a write-lock on the table (if required),
+  **   (d) there are no conflicting read-locks, and
+  **   (e) the cursor points at a valid row of an intKey table.
   */
   if( !pCsr->wrFlag ){
     return SQLITE_READONLY;
   }
-  assert( !pCsr->pBt->readOnly 
-          && pCsr->pBt->inTransaction==TRANS_WRITE );
-  if( checkReadLocks(pCsr->pBtree, pCsr->pgnoRoot, pCsr, 0) ){
-    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
-  }
-  if( pCsr->eState==CURSOR_INVALID || !pCsr->apPage[pCsr->iPage]->intKey ){
-    return SQLITE_ERROR;
-  }
+  assert( (pCsr->pBt->btsFlags & BTS_READ_ONLY)==0
+              && pCsr->pBt->inTransaction==TRANS_WRITE );
+  assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
+  assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
+  assert( pCsr->apPage[pCsr->iPage]->intKey );
 
-  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 0, 1);
+  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 1);
 }
 
 /* 
@@ -43727,13 +56192,776 @@ SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void
 SQLITE_PRIVATE void sqlite3BtreeCacheOverflow(BtCursor *pCur){
   assert( cursorHoldsMutex(pCur) );
   assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
-  assert(!pCur->isIncrblobHandle);
-  assert(!pCur->aOverflow);
+  invalidateOverflowCache(pCur);
   pCur->isIncrblobHandle = 1;
 }
 #endif
 
+/*
+** Set both the "read version" (single byte at byte offset 18) and 
+** "write version" (single byte at byte offset 19) fields in the database
+** header to iVersion.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
+  BtShared *pBt = pBtree->pBt;
+  int rc;                         /* Return code */
+ 
+  assert( iVersion==1 || iVersion==2 );
+
+  /* If setting the version fields to 1, do not automatically open the
+  ** WAL connection, even if the version fields are currently set to 2.
+  */
+  pBt->btsFlags &= ~BTS_NO_WAL;
+  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;
+
+  rc = sqlite3BtreeBeginTrans(pBtree, 0);
+  if( rc==SQLITE_OK ){
+    u8 *aData = pBt->pPage1->aData;
+    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
+      rc = sqlite3BtreeBeginTrans(pBtree, 2);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+        if( rc==SQLITE_OK ){
+          aData[18] = (u8)iVersion;
+          aData[19] = (u8)iVersion;
+        }
+      }
+    }
+  }
+
+  pBt->btsFlags &= ~BTS_NO_WAL;
+  return rc;
+}
+
+/*
+** set the mask of hint flags for cursor pCsr. Currently the only valid
+** values are 0 and BTREE_BULKLOAD.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorHints(BtCursor *pCsr, unsigned int mask){
+  assert( mask==BTREE_BULKLOAD || mask==0 );
+  pCsr->hints = mask;
+}
+
 /************** End of btree.c ***********************************************/
+/************** Begin file backup.c ******************************************/
+/*
+** 2009 January 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation of the sqlite3_backup_XXX() 
+** API functions and the related features.
+*/
+
+/* Macro to find the minimum of two numeric values.
+*/
+#ifndef MIN
+# define MIN(x,y) ((x)<(y)?(x):(y))
+#endif
+
+/*
+** Structure allocated for each backup operation.
+*/
+struct sqlite3_backup {
+  sqlite3* pDestDb;        /* Destination database handle */
+  Btree *pDest;            /* Destination b-tree file */
+  u32 iDestSchema;         /* Original schema cookie in destination */
+  int bDestLocked;         /* True once a write-transaction is open on pDest */
+
+  Pgno iNext;              /* Page number of the next source page to copy */
+  sqlite3* pSrcDb;         /* Source database handle */
+  Btree *pSrc;             /* Source b-tree file */
+
+  int rc;                  /* Backup process error code */
+
+  /* These two variables are set by every call to backup_step(). They are
+  ** read by calls to backup_remaining() and backup_pagecount().
+  */
+  Pgno nRemaining;         /* Number of pages left to copy */
+  Pgno nPagecount;         /* Total number of pages to copy */
+
+  int isAttached;          /* True once backup has been registered with pager */
+  sqlite3_backup *pNext;   /* Next backup associated with source pager */
+};
+
+/*
+** THREAD SAFETY NOTES:
+**
+**   Once it has been created using backup_init(), a single sqlite3_backup
+**   structure may be accessed via two groups of thread-safe entry points:
+**
+**     * Via the sqlite3_backup_XXX() API function backup_step() and 
+**       backup_finish(). Both these functions obtain the source database
+**       handle mutex and the mutex associated with the source BtShared 
+**       structure, in that order.
+**
+**     * Via the BackupUpdate() and BackupRestart() functions, which are
+**       invoked by the pager layer to report various state changes in
+**       the page cache associated with the source database. The mutex
+**       associated with the source database BtShared structure will always 
+**       be held when either of these functions are invoked.
+**
+**   The other sqlite3_backup_XXX() API functions, backup_remaining() and
+**   backup_pagecount() are not thread-safe functions. If they are called
+**   while some other thread is calling backup_step() or backup_finish(),
+**   the values returned may be invalid. There is no way for a call to
+**   BackupUpdate() or BackupRestart() to interfere with backup_remaining()
+**   or backup_pagecount().
+**
+**   Depending on the SQLite configuration, the database handles and/or
+**   the Btree objects may have their own mutexes that require locking.
+**   Non-sharable Btrees (in-memory databases for example), do not have
+**   associated mutexes.
+*/
+
+/*
+** Return a pointer corresponding to database zDb (i.e. "main", "temp")
+** in connection handle pDb. If such a database cannot be found, return
+** a NULL pointer and write an error message to pErrorDb.
+**
+** If the "temp" database is requested, it may need to be opened by this 
+** function. If an error occurs while doing so, return 0 and write an 
+** error message to pErrorDb.
+*/
+static Btree *findBtree(sqlite3 *pErrorDb, sqlite3 *pDb, const char *zDb){
+  int i = sqlite3FindDbName(pDb, zDb);
+
+  if( i==1 ){
+    Parse *pParse;
+    int rc = 0;
+    pParse = sqlite3StackAllocZero(pErrorDb, sizeof(*pParse));
+    if( pParse==0 ){
+      sqlite3Error(pErrorDb, SQLITE_NOMEM, "out of memory");
+      rc = SQLITE_NOMEM;
+    }else{
+      pParse->db = pDb;
+      if( sqlite3OpenTempDatabase(pParse) ){
+        sqlite3Error(pErrorDb, pParse->rc, "%s", pParse->zErrMsg);
+        rc = SQLITE_ERROR;
+      }
+      sqlite3DbFree(pErrorDb, pParse->zErrMsg);
+      sqlite3StackFree(pErrorDb, pParse);
+    }
+    if( rc ){
+      return 0;
+    }
+  }
+
+  if( i<0 ){
+    sqlite3Error(pErrorDb, SQLITE_ERROR, "unknown database %s", zDb);
+    return 0;
+  }
+
+  return pDb->aDb[i].pBt;
+}
+
+/*
+** Attempt to set the page size of the destination to match the page size
+** of the source.
+*/
+static int setDestPgsz(sqlite3_backup *p){
+  int rc;
+  rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),-1,0);
+  return rc;
+}
+
+/*
+** Create an sqlite3_backup process to copy the contents of zSrcDb from
+** connection handle pSrcDb to zDestDb in pDestDb. If successful, return
+** a pointer to the new sqlite3_backup object.
+**
+** If an error occurs, NULL is returned and an error code and error message
+** stored in database handle pDestDb.
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3* pDestDb,                     /* Database to write to */
+  const char *zDestDb,                  /* Name of database within pDestDb */
+  sqlite3* pSrcDb,                      /* Database connection to read from */
+  const char *zSrcDb                    /* Name of database within pSrcDb */
+){
+  sqlite3_backup *p;                    /* Value to return */
+
+  /* Lock the source database handle. The destination database
+  ** handle is not locked in this routine, but it is locked in
+  ** sqlite3_backup_step(). The user is required to ensure that no
+  ** other thread accesses the destination handle for the duration
+  ** of the backup operation.  Any attempt to use the destination
+  ** database connection while a backup is in progress may cause
+  ** a malfunction or a deadlock.
+  */
+  sqlite3_mutex_enter(pSrcDb->mutex);
+  sqlite3_mutex_enter(pDestDb->mutex);
+
+  if( pSrcDb==pDestDb ){
+    sqlite3Error(
+        pDestDb, SQLITE_ERROR, "source and destination must be distinct"
+    );
+    p = 0;
+  }else {
+    /* Allocate space for a new sqlite3_backup object...
+    ** EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
+    ** call to sqlite3_backup_init() and is destroyed by a call to
+    ** sqlite3_backup_finish(). */
+    p = (sqlite3_backup *)sqlite3MallocZero(sizeof(sqlite3_backup));
+    if( !p ){
+      sqlite3Error(pDestDb, SQLITE_NOMEM, 0);
+    }
+  }
+
+  /* If the allocation succeeded, populate the new object. */
+  if( p ){
+    p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb);
+    p->pDest = findBtree(pDestDb, pDestDb, zDestDb);
+    p->pDestDb = pDestDb;
+    p->pSrcDb = pSrcDb;
+    p->iNext = 1;
+    p->isAttached = 0;
+
+    if( 0==p->pSrc || 0==p->pDest || setDestPgsz(p)==SQLITE_NOMEM ){
+      /* One (or both) of the named databases did not exist or an OOM
+      ** error was hit.  The error has already been written into the
+      ** pDestDb handle.  All that is left to do here is free the
+      ** sqlite3_backup structure.
+      */
+      sqlite3_free(p);
+      p = 0;
+    }
+  }
+  if( p ){
+    p->pSrc->nBackup++;
+  }
+
+  sqlite3_mutex_leave(pDestDb->mutex);
+  sqlite3_mutex_leave(pSrcDb->mutex);
+  return p;
+}
+
+/*
+** Argument rc is an SQLite error code. Return true if this error is 
+** considered fatal if encountered during a backup operation. All errors
+** are considered fatal except for SQLITE_BUSY and SQLITE_LOCKED.
+*/
+static int isFatalError(int rc){
+  return (rc!=SQLITE_OK && rc!=SQLITE_BUSY && ALWAYS(rc!=SQLITE_LOCKED));
+}
+
+/*
+** Parameter zSrcData points to a buffer containing the data for 
+** page iSrcPg from the source database. Copy this data into the 
+** destination database.
+*/
+static int backupOnePage(sqlite3_backup *p, Pgno iSrcPg, const u8 *zSrcData){
+  Pager * const pDestPager = sqlite3BtreePager(p->pDest);
+  const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
+  int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
+  const int nCopy = MIN(nSrcPgsz, nDestPgsz);
+  const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
+#ifdef SQLITE_HAS_CODEC
+  int nSrcReserve = sqlite3BtreeGetReserve(p->pSrc);
+  int nDestReserve = sqlite3BtreeGetReserve(p->pDest);
+#endif
+
+  int rc = SQLITE_OK;
+  i64 iOff;
+
+  assert( p->bDestLocked );
+  assert( !isFatalError(p->rc) );
+  assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
+  assert( zSrcData );
+
+  /* Catch the case where the destination is an in-memory database and the
+  ** page sizes of the source and destination differ. 
+  */
+  if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(pDestPager) ){
+    rc = SQLITE_READONLY;
+  }
+
+#ifdef SQLITE_HAS_CODEC
+  /* Backup is not possible if the page size of the destination is changing
+  ** and a codec is in use.
+  */
+  if( nSrcPgsz!=nDestPgsz && sqlite3PagerGetCodec(pDestPager)!=0 ){
+    rc = SQLITE_READONLY;
+  }
+
+  /* Backup is not possible if the number of bytes of reserve space differ
+  ** between source and destination.  If there is a difference, try to
+  ** fix the destination to agree with the source.  If that is not possible,
+  ** then the backup cannot proceed.
+  */
+  if( nSrcReserve!=nDestReserve ){
+    u32 newPgsz = nSrcPgsz;
+    rc = sqlite3PagerSetPagesize(pDestPager, &newPgsz, nSrcReserve);
+    if( rc==SQLITE_OK && newPgsz!=nSrcPgsz ) rc = SQLITE_READONLY;
+  }
+#endif
+
+  /* This loop runs once for each destination page spanned by the source 
+  ** page. For each iteration, variable iOff is set to the byte offset
+  ** of the destination page.
+  */
+  for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
+    DbPage *pDestPg = 0;
+    Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
+    if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
+    if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg))
+     && SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
+    ){
+      const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
+      u8 *zDestData = sqlite3PagerGetData(pDestPg);
+      u8 *zOut = &zDestData[iOff%nDestPgsz];
+
+      /* Copy the data from the source page into the destination page.
+      ** Then clear the Btree layer MemPage.isInit flag. Both this module
+      ** and the pager code use this trick (clearing the first byte
+      ** of the page 'extra' space to invalidate the Btree layers
+      ** cached parse of the page). MemPage.isInit is marked 
+      ** "MUST BE FIRST" for this purpose.
+      */
+      memcpy(zOut, zIn, nCopy);
+      ((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
+    }
+    sqlite3PagerUnref(pDestPg);
+  }
+
+  return rc;
+}
+
+/*
+** If pFile is currently larger than iSize bytes, then truncate it to
+** exactly iSize bytes. If pFile is not larger than iSize bytes, then
+** this function is a no-op.
+**
+** Return SQLITE_OK if everything is successful, or an SQLite error 
+** code if an error occurs.
+*/
+static int backupTruncateFile(sqlite3_file *pFile, i64 iSize){
+  i64 iCurrent;
+  int rc = sqlite3OsFileSize(pFile, &iCurrent);
+  if( rc==SQLITE_OK && iCurrent>iSize ){
+    rc = sqlite3OsTruncate(pFile, iSize);
+  }
+  return rc;
+}
+
+/*
+** Register this backup object with the associated source pager for
+** callbacks when pages are changed or the cache invalidated.
+*/
+static void attachBackupObject(sqlite3_backup *p){
+  sqlite3_backup **pp;
+  assert( sqlite3BtreeHoldsMutex(p->pSrc) );
+  pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
+  p->pNext = *pp;
+  *pp = p;
+  p->isAttached = 1;
+}
+
+/*
+** Copy nPage pages from the source b-tree to the destination.
+*/
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage){
+  int rc;
+  int destMode;       /* Destination journal mode */
+  int pgszSrc = 0;    /* Source page size */
+  int pgszDest = 0;   /* Destination page size */
+
+  sqlite3_mutex_enter(p->pSrcDb->mutex);
+  sqlite3BtreeEnter(p->pSrc);
+  if( p->pDestDb ){
+    sqlite3_mutex_enter(p->pDestDb->mutex);
+  }
+
+  rc = p->rc;
+  if( !isFatalError(rc) ){
+    Pager * const pSrcPager = sqlite3BtreePager(p->pSrc);     /* Source pager */
+    Pager * const pDestPager = sqlite3BtreePager(p->pDest);   /* Dest pager */
+    int ii;                            /* Iterator variable */
+    int nSrcPage = -1;                 /* Size of source db in pages */
+    int bCloseTrans = 0;               /* True if src db requires unlocking */
+
+    /* If the source pager is currently in a write-transaction, return
+    ** SQLITE_BUSY immediately.
+    */
+    if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){
+      rc = SQLITE_BUSY;
+    }else{
+      rc = SQLITE_OK;
+    }
+
+    /* Lock the destination database, if it is not locked already. */
+    if( SQLITE_OK==rc && p->bDestLocked==0
+     && SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2)) 
+    ){
+      p->bDestLocked = 1;
+      sqlite3BtreeGetMeta(p->pDest, BTREE_SCHEMA_VERSION, &p->iDestSchema);
+    }
+
+    /* If there is no open read-transaction on the source database, open
+    ** one now. If a transaction is opened here, then it will be closed
+    ** before this function exits.
+    */
+    if( rc==SQLITE_OK && 0==sqlite3BtreeIsInReadTrans(p->pSrc) ){
+      rc = sqlite3BtreeBeginTrans(p->pSrc, 0);
+      bCloseTrans = 1;
+    }
+
+    /* Do not allow backup if the destination database is in WAL mode
+    ** and the page sizes are different between source and destination */
+    pgszSrc = sqlite3BtreeGetPageSize(p->pSrc);
+    pgszDest = sqlite3BtreeGetPageSize(p->pDest);
+    destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest));
+    if( SQLITE_OK==rc && destMode==PAGER_JOURNALMODE_WAL && pgszSrc!=pgszDest ){
+      rc = SQLITE_READONLY;
+    }
+  
+    /* Now that there is a read-lock on the source database, query the
+    ** source pager for the number of pages in the database.
+    */
+    nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc);
+    assert( nSrcPage>=0 );
+    for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){
+      const Pgno iSrcPg = p->iNext;                 /* Source page number */
+      if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){
+        DbPage *pSrcPg;                             /* Source page object */
+        rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg);
+        if( rc==SQLITE_OK ){
+          rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg));
+          sqlite3PagerUnref(pSrcPg);
+        }
+      }
+      p->iNext++;
+    }
+    if( rc==SQLITE_OK ){
+      p->nPagecount = nSrcPage;
+      p->nRemaining = nSrcPage+1-p->iNext;
+      if( p->iNext>(Pgno)nSrcPage ){
+        rc = SQLITE_DONE;
+      }else if( !p->isAttached ){
+        attachBackupObject(p);
+      }
+    }
+  
+    /* Update the schema version field in the destination database. This
+    ** is to make sure that the schema-version really does change in
+    ** the case where the source and destination databases have the
+    ** same schema version.
+    */
+    if( rc==SQLITE_DONE ){
+      rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1);
+      if( rc==SQLITE_OK ){
+        if( p->pDestDb ){
+          sqlite3ResetAllSchemasOfConnection(p->pDestDb);
+        }
+        if( destMode==PAGER_JOURNALMODE_WAL ){
+          rc = sqlite3BtreeSetVersion(p->pDest, 2);
+        }
+      }
+      if( rc==SQLITE_OK ){
+        int nDestTruncate;
+        /* Set nDestTruncate to the final number of pages in the destination
+        ** database. The complication here is that the destination page
+        ** size may be different to the source page size. 
+        **
+        ** If the source page size is smaller than the destination page size, 
+        ** round up. In this case the call to sqlite3OsTruncate() below will
+        ** fix the size of the file. However it is important to call
+        ** sqlite3PagerTruncateImage() here so that any pages in the 
+        ** destination file that lie beyond the nDestTruncate page mark are
+        ** journalled by PagerCommitPhaseOne() before they are destroyed
+        ** by the file truncation.
+        */
+        assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) );
+        assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) );
+        if( pgszSrc<pgszDest ){
+          int ratio = pgszDest/pgszSrc;
+          nDestTruncate = (nSrcPage+ratio-1)/ratio;
+          if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){
+            nDestTruncate--;
+          }
+        }else{
+          nDestTruncate = nSrcPage * (pgszSrc/pgszDest);
+        }
+        sqlite3PagerTruncateImage(pDestPager, nDestTruncate);
+
+        if( pgszSrc<pgszDest ){
+          /* If the source page-size is smaller than the destination page-size,
+          ** two extra things may need to happen:
+          **
+          **   * The destination may need to be truncated, and
+          **
+          **   * Data stored on the pages immediately following the 
+          **     pending-byte page in the source database may need to be
+          **     copied into the destination database.
+          */
+          const i64 iSize = (i64)pgszSrc * (i64)nSrcPage;
+          sqlite3_file * const pFile = sqlite3PagerFile(pDestPager);
+          i64 iOff;
+          i64 iEnd;
+
+          assert( pFile );
+          assert( (i64)nDestTruncate*(i64)pgszDest >= iSize || (
+                nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1)
+             && iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest
+          ));
+
+          /* This call ensures that all data required to recreate the original
+          ** database has been stored in the journal for pDestPager and the
+          ** journal synced to disk. So at this point we may safely modify
+          ** the database file in any way, knowing that if a power failure
+          ** occurs, the original database will be reconstructed from the 
+          ** journal file.  */
+          rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1);
+
+          /* Write the extra pages and truncate the database file as required */
+          iEnd = MIN(PENDING_BYTE + pgszDest, iSize);
+          for(
+            iOff=PENDING_BYTE+pgszSrc; 
+            rc==SQLITE_OK && iOff<iEnd; 
+            iOff+=pgszSrc
+          ){
+            PgHdr *pSrcPg = 0;
+            const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1);
+            rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg);
+            if( rc==SQLITE_OK ){
+              u8 *zData = sqlite3PagerGetData(pSrcPg);
+              rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff);
+            }
+            sqlite3PagerUnref(pSrcPg);
+          }
+          if( rc==SQLITE_OK ){
+            rc = backupTruncateFile(pFile, iSize);
+          }
+
+          /* Sync the database file to disk. */
+          if( rc==SQLITE_OK ){
+            rc = sqlite3PagerSync(pDestPager);
+          }
+        }else{
+          rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0);
+        }
+    
+        /* Finish committing the transaction to the destination database. */
+        if( SQLITE_OK==rc
+         && SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest, 0))
+        ){
+          rc = SQLITE_DONE;
+        }
+      }
+    }
+  
+    /* If bCloseTrans is true, then this function opened a read transaction
+    ** on the source database. Close the read transaction here. There is
+    ** no need to check the return values of the btree methods here, as
+    ** "committing" a read-only transaction cannot fail.
+    */
+    if( bCloseTrans ){
+      TESTONLY( int rc2 );
+      TESTONLY( rc2  = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0);
+      TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc, 0);
+      assert( rc2==SQLITE_OK );
+    }
+  
+    if( rc==SQLITE_IOERR_NOMEM ){
+      rc = SQLITE_NOMEM;
+    }
+    p->rc = rc;
+  }
+  if( p->pDestDb ){
+    sqlite3_mutex_leave(p->pDestDb->mutex);
+  }
+  sqlite3BtreeLeave(p->pSrc);
+  sqlite3_mutex_leave(p->pSrcDb->mutex);
+  return rc;
+}
+
+/*
+** Release all resources associated with an sqlite3_backup* handle.
+*/
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p){
+  sqlite3_backup **pp;                 /* Ptr to head of pagers backup list */
+  sqlite3 *pSrcDb;                     /* Source database connection */
+  int rc;                              /* Value to return */
+
+  /* Enter the mutexes */
+  if( p==0 ) return SQLITE_OK;
+  pSrcDb = p->pSrcDb;
+  sqlite3_mutex_enter(pSrcDb->mutex);
+  sqlite3BtreeEnter(p->pSrc);
+  if( p->pDestDb ){
+    sqlite3_mutex_enter(p->pDestDb->mutex);
+  }
+
+  /* Detach this backup from the source pager. */
+  if( p->pDestDb ){
+    p->pSrc->nBackup--;
+  }
+  if( p->isAttached ){
+    pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
+    while( *pp!=p ){
+      pp = &(*pp)->pNext;
+    }
+    *pp = p->pNext;
+  }
+
+  /* If a transaction is still open on the Btree, roll it back. */
+  sqlite3BtreeRollback(p->pDest, SQLITE_OK);
+
+  /* Set the error code of the destination database handle. */
+  rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc;
+  sqlite3Error(p->pDestDb, rc, 0);
+
+  /* Exit the mutexes and free the backup context structure. */
+  if( p->pDestDb ){
+    sqlite3LeaveMutexAndCloseZombie(p->pDestDb);
+  }
+  sqlite3BtreeLeave(p->pSrc);
+  if( p->pDestDb ){
+    /* EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
+    ** call to sqlite3_backup_init() and is destroyed by a call to
+    ** sqlite3_backup_finish(). */
+    sqlite3_free(p);
+  }
+  sqlite3LeaveMutexAndCloseZombie(pSrcDb);
+  return rc;
+}
+
+/*
+** Return the number of pages still to be backed up as of the most recent
+** call to sqlite3_backup_step().
+*/
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p){
+  return p->nRemaining;
+}
+
+/*
+** Return the total number of pages in the source database as of the most 
+** recent call to sqlite3_backup_step().
+*/
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p){
+  return p->nPagecount;
+}
+
+/*
+** This function is called after the contents of page iPage of the
+** source database have been modified. If page iPage has already been 
+** copied into the destination database, then the data written to the
+** destination is now invalidated. The destination copy of iPage needs
+** to be updated with the new data before the backup operation is
+** complete.
+**
+** It is assumed that the mutex associated with the BtShared object
+** corresponding to the source database is held when this function is
+** called.
+*/
+SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *pBackup, Pgno iPage, const u8 *aData){
+  sqlite3_backup *p;                   /* Iterator variable */
+  for(p=pBackup; p; p=p->pNext){
+    assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) );
+    if( !isFatalError(p->rc) && iPage<p->iNext ){
+      /* The backup process p has already copied page iPage. But now it
+      ** has been modified by a transaction on the source pager. Copy
+      ** the new data into the backup.
+      */
+      int rc;
+      assert( p->pDestDb );
+      sqlite3_mutex_enter(p->pDestDb->mutex);
+      rc = backupOnePage(p, iPage, aData);
+      sqlite3_mutex_leave(p->pDestDb->mutex);
+      assert( rc!=SQLITE_BUSY && rc!=SQLITE_LOCKED );
+      if( rc!=SQLITE_OK ){
+        p->rc = rc;
+      }
+    }
+  }
+}
+
+/*
+** Restart the backup process. This is called when the pager layer
+** detects that the database has been modified by an external database
+** connection. In this case there is no way of knowing which of the
+** pages that have been copied into the destination database are still 
+** valid and which are not, so the entire process needs to be restarted.
+**
+** It is assumed that the mutex associated with the BtShared object
+** corresponding to the source database is held when this function is
+** called.
+*/
+SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *pBackup){
+  sqlite3_backup *p;                   /* Iterator variable */
+  for(p=pBackup; p; p=p->pNext){
+    assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) );
+    p->iNext = 1;
+  }
+}
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Copy the complete content of pBtFrom into pBtTo.  A transaction
+** must be active for both files.
+**
+** The size of file pTo may be reduced by this operation. If anything 
+** goes wrong, the transaction on pTo is rolled back. If successful, the 
+** transaction is committed before returning.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
+  int rc;
+  sqlite3_file *pFd;              /* File descriptor for database pTo */
+  sqlite3_backup b;
+  sqlite3BtreeEnter(pTo);
+  sqlite3BtreeEnter(pFrom);
+
+  assert( sqlite3BtreeIsInTrans(pTo) );
+  pFd = sqlite3PagerFile(sqlite3BtreePager(pTo));
+  if( pFd->pMethods ){
+    i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom);
+    rc = sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);
+    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+    if( rc ) goto copy_finished;
+  }
+
+  /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set
+  ** to 0. This is used by the implementations of sqlite3_backup_step()
+  ** and sqlite3_backup_finish() to detect that they are being called
+  ** from this function, not directly by the user.
+  */
+  memset(&b, 0, sizeof(b));
+  b.pSrcDb = pFrom->db;
+  b.pSrc = pFrom;
+  b.pDest = pTo;
+  b.iNext = 1;
+
+  /* 0x7FFFFFFF is the hard limit for the number of pages in a database
+  ** file. By passing this as the number of pages to copy to
+  ** sqlite3_backup_step(), we can guarantee that the copy finishes 
+  ** within a single call (unless an error occurs). The assert() statement
+  ** checks this assumption - (p->rc) should be set to either SQLITE_DONE 
+  ** or an error code.
+  */
+  sqlite3_backup_step(&b, 0x7FFFFFFF);
+  assert( b.rc!=SQLITE_OK );
+  rc = sqlite3_backup_finish(&b);
+  if( rc==SQLITE_OK ){
+    pTo->pBt->btsFlags &= ~BTS_PAGESIZE_FIXED;
+  }else{
+    sqlite3PagerClearCache(sqlite3BtreePager(b.pDest));
+  }
+
+  assert( sqlite3BtreeIsInTrans(pTo)==0 );
+copy_finished:
+  sqlite3BtreeLeave(pFrom);
+  sqlite3BtreeLeave(pTo);
+  return rc;
+}
+#endif /* SQLITE_OMIT_VACUUM */
+
+/************** End of backup.c **********************************************/
 /************** Begin file vdbemem.c *****************************************/
 /*
 ** 2004 May 26
@@ -43751,16 +56979,8 @@ SQLITE_PRIVATE void sqlite3BtreeCacheOverflow(BtCursor *pCur){
 ** stores a single value in the VDBE.  Mem is an opaque structure visible
 ** only within the VDBE.  Interface routines refer to a Mem using the
 ** name sqlite_value
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
-/*
-** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
-** P if required.
-*/
-#define expandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
-
 /*
 ** If pMem is an object with a valid string representation, this routine
 ** ensures the internal encoding for the string representation is
@@ -43802,10 +57022,10 @@ SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
 ** Make sure pMem->z points to a writable allocation of at least 
 ** n bytes.
 **
-** If the memory cell currently contains string or blob data
-** and the third argument passed to this function is true, the 
-** current content of the cell is preserved. Otherwise, it may
-** be discarded.  
+** If the third argument passed to this function is true, then memory
+** cell pMem must contain a string or blob. In this case the content is
+** preserved. Otherwise, if the third parameter to this function is false,
+** any current string or blob value may be discarded.
 **
 ** This function sets the MEM_Dyn flag and clears any xDel callback.
 ** It also clears MEM_Ephem and MEM_Static. If the preserve flag is 
@@ -43820,6 +57040,10 @@ SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve){
   );
   assert( (pMem->flags&MEM_RowSet)==0 );
 
+  /* If the preserve flag is set to true, then the memory cell must already
+  ** contain a valid string or blob value.  */
+  assert( preserve==0 || pMem->flags&(MEM_Blob|MEM_Str) );
+
   if( n<32 ) n = 32;
   if( sqlite3DbMallocSize(pMem->db, pMem->zMalloc)<n ){
     if( preserve && pMem->z==pMem->zMalloc ){
@@ -43831,10 +57055,11 @@ SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve){
     }
   }
 
-  if( preserve && pMem->z && pMem->zMalloc && pMem->z!=pMem->zMalloc ){
+  if( pMem->z && preserve && pMem->zMalloc && pMem->z!=pMem->zMalloc ){
     memcpy(pMem->zMalloc, pMem->z, pMem->n);
   }
   if( pMem->flags&MEM_Dyn && pMem->xDel ){
+    assert( pMem->xDel!=SQLITE_DYNAMIC );
     pMem->xDel((void *)(pMem->z));
   }
 
@@ -43860,7 +57085,7 @@ SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem *pMem){
   int f;
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
   assert( (pMem->flags&MEM_RowSet)==0 );
-  expandBlob(pMem);
+  ExpandBlob(pMem);
   f = pMem->flags;
   if( (f&(MEM_Str|MEM_Blob)) && pMem->z!=pMem->zMalloc ){
     if( sqlite3VdbeMemGrow(pMem, pMem->n + 2, 1) ){
@@ -43869,6 +57094,9 @@ SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem *pMem){
     pMem->z[pMem->n] = 0;
     pMem->z[pMem->n+1] = 0;
     pMem->flags |= MEM_Term;
+#ifdef SQLITE_DEBUG
+    pMem->pScopyFrom = 0;
+#endif
   }
 
   return SQLITE_OK;
@@ -43944,6 +57172,7 @@ SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem *pMem, int enc){
   assert( !(fg&(MEM_Str|MEM_Blob)) );
   assert( fg&(MEM_Int|MEM_Real) );
   assert( (pMem->flags&MEM_RowSet)==0 );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 
 
   if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
@@ -43979,7 +57208,7 @@ SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem *pMem, int enc){
 */
 SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
   int rc = SQLITE_OK;
-  if( pFunc && pFunc->xFinalize ){
+  if( ALWAYS(pFunc && pFunc->xFinalize) ){
     sqlite3_context ctx;
     assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
     assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
@@ -43988,11 +57217,11 @@ SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
     ctx.s.db = pMem->db;
     ctx.pMem = pMem;
     ctx.pFunc = pFunc;
-    pFunc->xFinalize(&ctx);
+    pFunc->xFinalize(&ctx); /* IMP: R-24505-23230 */
     assert( 0==(pMem->flags&MEM_Dyn) && !pMem->xDel );
     sqlite3DbFree(pMem->db, pMem->zMalloc);
     memcpy(pMem, &ctx.s, sizeof(ctx.s));
-    rc = (ctx.isError?SQLITE_ERROR:SQLITE_OK);
+    rc = ctx.isError;
   }
   return rc;
 }
@@ -44010,10 +57239,13 @@ SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p){
     sqlite3VdbeMemRelease(p);
   }else if( p->flags&MEM_Dyn && p->xDel ){
     assert( (p->flags&MEM_RowSet)==0 );
+    assert( p->xDel!=SQLITE_DYNAMIC );
     p->xDel((void *)p->z);
     p->xDel = 0;
   }else if( p->flags&MEM_RowSet ){
     sqlite3RowSetClear(p->u.pRowSet);
+  }else if( p->flags&MEM_Frame ){
+    sqlite3VdbeMemSetNull(p);
   }
 }
 
@@ -44023,7 +57255,7 @@ SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p){
 ** (Mem.type==SQLITE_TEXT).
 */
 SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p){
-  sqlite3VdbeMemReleaseExternal(p);
+  VdbeMemRelease(p);
   sqlite3DbFree(p->db, p->zMalloc);
   p->z = 0;
   p->zMalloc = 0;
@@ -44043,6 +57275,10 @@ SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p){
 ** before attempting the conversion.
 */
 static i64 doubleToInt64(double r){
+#ifdef SQLITE_OMIT_FLOATING_POINT
+  /* When floating-point is omitted, double and int64 are the same thing */
+  return r;
+#else
   /*
   ** Many compilers we encounter do not define constants for the
   ** minimum and maximum 64-bit integers, or they define them
@@ -44056,10 +57292,15 @@ static i64 doubleToInt64(double r){
   if( r<(double)minInt ){
     return minInt;
   }else if( r>(double)maxInt ){
+    /* minInt is correct here - not maxInt.  It turns out that assigning
+    ** a very large positive number to an integer results in a very large
+    ** negative integer.  This makes no sense, but it is what x86 hardware
+    ** does so for compatibility we will do the same in software. */
     return minInt;
   }else{
     return (i64)r;
   }
+#endif
 }
 
 /*
@@ -44068,27 +57309,25 @@ static i64 doubleToInt64(double r){
 ** If pMem is an integer, then the value is exact.  If pMem is
 ** a floating-point then the value returned is the integer part.
 ** If pMem is a string or blob, then we make an attempt to convert
-** it into a integer and return that.  If pMem is NULL, return 0.
+** it into a integer and return that.  If pMem represents an
+** an SQL-NULL value, return 0.
 **
-** If pMem is a string, its encoding might be changed.
+** If pMem represents a string value, its encoding might be changed.
 */
 SQLITE_PRIVATE i64 sqlite3VdbeIntValue(Mem *pMem){
   int flags;
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
   flags = pMem->flags;
   if( flags & MEM_Int ){
     return pMem->u.i;
   }else if( flags & MEM_Real ){
     return doubleToInt64(pMem->r);
   }else if( flags & (MEM_Str|MEM_Blob) ){
-    i64 value;
-    pMem->flags |= MEM_Str;
-    if( sqlite3VdbeChangeEncoding(pMem, SQLITE_UTF8)
-       || sqlite3VdbeMemNulTerminate(pMem) ){
-      return 0;
-    }
-    assert( pMem->z );
-    sqlite3Atoi64(pMem->z, &value);
+    i64 value = 0;
+    assert( pMem->z || pMem->n==0 );
+    testcase( pMem->z==0 );
+    sqlite3Atoi64(pMem->z, &value, pMem->n, pMem->enc);
     return value;
   }else{
     return 0;
@@ -44103,22 +57342,19 @@ SQLITE_PRIVATE i64 sqlite3VdbeIntValue(Mem *pMem){
 */
 SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem *pMem){
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
   if( pMem->flags & MEM_Real ){
     return pMem->r;
   }else if( pMem->flags & MEM_Int ){
     return (double)pMem->u.i;
   }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
-    double val = 0.0;
-    pMem->flags |= MEM_Str;
-    if( sqlite3VdbeChangeEncoding(pMem, SQLITE_UTF8)
-       || sqlite3VdbeMemNulTerminate(pMem) ){
-      return 0.0;
-    }
-    assert( pMem->z );
-    sqlite3AtoF(pMem->z, &val);
+    /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+    double val = (double)0;
+    sqlite3AtoF(pMem->z, &val, pMem->n, pMem->enc);
     return val;
   }else{
-    return 0.0;
+    /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+    return (double)0;
   }
 }
 
@@ -44130,9 +57366,30 @@ SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem *pMem){
   assert( pMem->flags & MEM_Real );
   assert( (pMem->flags & MEM_RowSet)==0 );
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 
   pMem->u.i = doubleToInt64(pMem->r);
-  if( pMem->r==(double)pMem->u.i ){
+
+  /* Only mark the value as an integer if
+  **
+  **    (1) the round-trip conversion real->int->real is a no-op, and
+  **    (2) The integer is neither the largest nor the smallest
+  **        possible integer (ticket #3922)
+  **
+  ** The second and third terms in the following conditional enforces
+  ** the second condition under the assumption that addition overflow causes
+  ** values to wrap around.  On x86 hardware, the third term is always
+  ** true and could be omitted.  But we leave it in because other
+  ** architectures might behave differently.
+  */
+  if( pMem->r==(double)pMem->u.i
+   && pMem->u.i>SMALLEST_INT64
+#if defined(__i486__) || defined(__x86_64__)
+   && ALWAYS(pMem->u.i<LARGEST_INT64)
+#else
+   && pMem->u.i<LARGEST_INT64
+#endif
+  ){
     pMem->flags |= MEM_Int;
   }
 }
@@ -44143,6 +57400,8 @@ SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem *pMem){
 SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem *pMem){
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
   assert( (pMem->flags & MEM_RowSet)==0 );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
   pMem->u.i = sqlite3VdbeIntValue(pMem);
   MemSetTypeFlag(pMem, MEM_Int);
   return SQLITE_OK;
@@ -44154,6 +57413,8 @@ SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem *pMem){
 */
 SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem *pMem){
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
   pMem->r = sqlite3VdbeRealValue(pMem);
   MemSetTypeFlag(pMem, MEM_Real);
   return SQLITE_OK;
@@ -44162,22 +57423,25 @@ SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem *pMem){
 /*
 ** Convert pMem so that it has types MEM_Real or MEM_Int or both.
 ** Invalidate any prior representations.
+**
+** Every effort is made to force the conversion, even if the input
+** is a string that does not look completely like a number.  Convert
+** as much of the string as we can and ignore the rest.
 */
 SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem *pMem){
-  double r1, r2;
-  i64 i;
-  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_Null))==0 );
-  assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
-  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
-  r1 = sqlite3VdbeRealValue(pMem);
-  i = doubleToInt64(r1);
-  r2 = (double)i;
-  if( r1==r2 ){
-    sqlite3VdbeMemIntegerify(pMem);
-  }else{
-    pMem->r = r1;
-    MemSetTypeFlag(pMem, MEM_Real);
+  if( (pMem->flags & (MEM_Int|MEM_Real|MEM_Null))==0 ){
+    assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
+    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+    if( 0==sqlite3Atoi64(pMem->z, &pMem->u.i, pMem->n, pMem->enc) ){
+      MemSetTypeFlag(pMem, MEM_Int);
+    }else{
+      pMem->r = sqlite3VdbeRealValue(pMem);
+      MemSetTypeFlag(pMem, MEM_Real);
+      sqlite3VdbeIntegerAffinity(pMem);
+    }
   }
+  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_Null))!=0 );
+  pMem->flags &= ~(MEM_Str|MEM_Blob);
   return SQLITE_OK;
 }
 
@@ -44185,6 +57449,11 @@ SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem *pMem){
 ** Delete any previous value and set the value stored in *pMem to NULL.
 */
 SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem *pMem){
+  if( pMem->flags & MEM_Frame ){
+    VdbeFrame *pFrame = pMem->u.pFrame;
+    pFrame->pParent = pFrame->v->pDelFrame;
+    pFrame->v->pDelFrame = pFrame;
+  }
   if( pMem->flags & MEM_RowSet ){
     sqlite3RowSetClear(pMem->u.pRowSet);
   }
@@ -44204,6 +57473,14 @@ SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
   if( n<0 ) n = 0;
   pMem->u.nZero = n;
   pMem->enc = SQLITE_UTF8;
+
+#ifdef SQLITE_OMIT_INCRBLOB
+  sqlite3VdbeMemGrow(pMem, n, 0);
+  if( pMem->z ){
+    pMem->n = n;
+    memset(pMem->z, 0, n);
+  }
+#endif
 }
 
 /*
@@ -44217,6 +57494,7 @@ SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
   pMem->type = SQLITE_INTEGER;
 }
 
+#ifndef SQLITE_OMIT_FLOATING_POINT
 /*
 ** Delete any previous value and set the value stored in *pMem to val,
 ** manifest type REAL.
@@ -44231,6 +57509,7 @@ SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
     pMem->type = SQLITE_FLOAT;
   }
 }
+#endif
 
 /*
 ** Delete any previous value and set the value of pMem to be an
@@ -44239,12 +57518,9 @@ SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
 SQLITE_PRIVATE void sqlite3VdbeMemSetRowSet(Mem *pMem){
   sqlite3 *db = pMem->db;
   assert( db!=0 );
-  if( pMem->flags & MEM_RowSet ){
-    sqlite3RowSetClear(pMem->u.pRowSet);
-  }else{
-    sqlite3VdbeMemRelease(pMem);
-    pMem->zMalloc = sqlite3DbMallocRaw(db, 64);
-  }
+  assert( (pMem->flags & MEM_RowSet)==0 );
+  sqlite3VdbeMemRelease(pMem);
+  pMem->zMalloc = sqlite3DbMallocRaw(db, 64);
   if( db->mallocFailed ){
     pMem->flags = MEM_Null;
   }else{
@@ -44272,6 +57548,28 @@ SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem *p){
   return 0; 
 }
 
+#ifdef SQLITE_DEBUG
+/*
+** This routine prepares a memory cell for modication by breaking
+** its link to a shallow copy and by marking any current shallow
+** copies of this cell as invalid.
+**
+** This is used for testing and debugging only - to make sure shallow
+** copies are not misused.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
+  int i;
+  Mem *pX;
+  for(i=1, pX=&pVdbe->aMem[1]; i<=pVdbe->nMem; i++, pX++){
+    if( pX->pScopyFrom==pMem ){
+      pX->flags |= MEM_Invalid;
+      pX->pScopyFrom = 0;
+    }
+  }
+  pMem->pScopyFrom = 0;
+}
+#endif /* SQLITE_DEBUG */
+
 /*
 ** Size of struct Mem not including the Mem.zMalloc member.
 */
@@ -44285,10 +57583,10 @@ SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem *p){
 */
 SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
   assert( (pFrom->flags & MEM_RowSet)==0 );
-  sqlite3VdbeMemReleaseExternal(pTo);
+  VdbeMemRelease(pTo);
   memcpy(pTo, pFrom, MEMCELLSIZE);
   pTo->xDel = 0;
-  if( (pFrom->flags&MEM_Dyn)!=0 || pFrom->z==pFrom->zMalloc ){
+  if( (pFrom->flags&MEM_Static)==0 ){
     pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
     assert( srcType==MEM_Ephem || srcType==MEM_Static );
     pTo->flags |= srcType;
@@ -44303,7 +57601,7 @@ SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
   int rc = SQLITE_OK;
 
   assert( (pFrom->flags & MEM_RowSet)==0 );
-  sqlite3VdbeMemReleaseExternal(pTo);
+  VdbeMemRelease(pTo);
   memcpy(pTo, pFrom, MEMCELLSIZE);
   pTo->flags &= ~MEM_Dyn;
 
@@ -44343,6 +57641,12 @@ SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
 ** string is copied into a (possibly existing) buffer managed by the 
 ** Mem structure. Otherwise, any existing buffer is freed and the
 ** pointer copied.
+**
+** If the string is too large (if it exceeds the SQLITE_LIMIT_LENGTH
+** size limit) then no memory allocation occurs.  If the string can be
+** stored without allocating memory, then it is.  If a memory allocation
+** is required to store the string, then value of pMem is unchanged.  In
+** either case, SQLITE_TOOBIG is returned.
 */
 SQLITE_PRIVATE int sqlite3VdbeMemSetStr(
   Mem *pMem,          /* Memory cell to set to string value */
@@ -44406,9 +57710,6 @@ SQLITE_PRIVATE int sqlite3VdbeMemSetStr(
     pMem->xDel = xDel;
     flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
   }
-  if( nByte>iLimit ){
-    return SQLITE_TOOBIG;
-  }
 
   pMem->n = nByte;
   pMem->flags = flags;
@@ -44421,6 +57722,10 @@ SQLITE_PRIVATE int sqlite3VdbeMemSetStr(
   }
 #endif
 
+  if( nByte>iLimit ){
+    return SQLITE_TOOBIG;
+  }
+
   return SQLITE_OK;
 }
 
@@ -44438,9 +57743,6 @@ SQLITE_PRIVATE int sqlite3MemCompare(const Mem *pMem1, const Mem *pMem2, const C
   int f1, f2;
   int combined_flags;
 
-  /* Interchange pMem1 and pMem2 if the collating sequence specifies
-  ** DESC order.
-  */
   f1 = pMem1->flags;
   f2 = pMem2->flags;
   combined_flags = f1|f2;
@@ -44565,13 +57867,14 @@ SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(
   int key,          /* If true, retrieve from the btree key, not data. */
   Mem *pMem         /* OUT: Return data in this Mem structure. */
 ){
-  char *zData;       /* Data from the btree layer */
-  int available = 0; /* Number of bytes available on the local btree page */
-  sqlite3 *db;       /* Database connection */
-  int rc = SQLITE_OK;
+  char *zData;        /* Data from the btree layer */
+  int available = 0;  /* Number of bytes available on the local btree page */
+  int rc = SQLITE_OK; /* Return code */
 
-  db = sqlite3BtreeCursorDb(pCur);
-  assert( sqlite3_mutex_held(db->mutex) );
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+
+  /* Note: the calls to BtreeKeyFetch() and DataFetch() below assert() 
+  ** that both the BtShared and database handle mutexes are held. */
   assert( (pMem->flags & MEM_RowSet)==0 );
   if( key ){
     zData = (char *)sqlite3BtreeKeyFetch(pCur, &available);
@@ -44580,7 +57883,7 @@ SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(
   }
   assert( zData!=0 );
 
-  if( offset+amt<=available && ((pMem->flags&MEM_Dyn)==0 || pMem->xDel) ){
+  if( offset+amt<=available && (pMem->flags&MEM_Dyn)==0 ){
     sqlite3VdbeMemRelease(pMem);
     pMem->z = &zData[offset];
     pMem->flags = MEM_Blob|MEM_Ephem;
@@ -44604,55 +57907,6 @@ SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(
   return rc;
 }
 
-#if 0
-/*
-** Perform various checks on the memory cell pMem. An assert() will
-** fail if pMem is internally inconsistent.
-*/
-SQLITE_PRIVATE void sqlite3VdbeMemSanity(Mem *pMem){
-  int flags = pMem->flags;
-  assert( flags!=0 );  /* Must define some type */
-  if( flags & (MEM_Str|MEM_Blob) ){
-    int x = flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short);
-    assert( x!=0 );            /* Strings must define a string subtype */
-    assert( (x & (x-1))==0 );  /* Only one string subtype can be defined */
-    assert( pMem->z!=0 );      /* Strings must have a value */
-    /* Mem.z points to Mem.zShort iff the subtype is MEM_Short */
-    assert( (x & MEM_Short)==0 || pMem->z==pMem->zShort );
-    assert( (x & MEM_Short)!=0 || pMem->z!=pMem->zShort );
-    /* No destructor unless there is MEM_Dyn */
-    assert( pMem->xDel==0 || (pMem->flags & MEM_Dyn)!=0 );
-
-    if( (flags & MEM_Str) ){
-      assert( pMem->enc==SQLITE_UTF8 || 
-              pMem->enc==SQLITE_UTF16BE ||
-              pMem->enc==SQLITE_UTF16LE 
-      );
-      /* If the string is UTF-8 encoded and nul terminated, then pMem->n
-      ** must be the length of the string.  (Later:)  If the database file
-      ** has been corrupted, '\000' characters might have been inserted
-      ** into the middle of the string.  In that case, the sqlite3Strlen30()
-      ** might be less.
-      */
-      if( pMem->enc==SQLITE_UTF8 && (flags & MEM_Term) ){ 
-        assert( sqlite3Strlen30(pMem->z)<=pMem->n );
-        assert( pMem->z[pMem->n]==0 );
-      }
-    }
-  }else{
-    /* Cannot define a string subtype for non-string objects */
-    assert( (pMem->flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short))==0 );
-    assert( pMem->xDel==0 );
-  }
-  /* MEM_Null excludes all other types */
-  assert( (pMem->flags&(MEM_Str|MEM_Int|MEM_Real|MEM_Blob))==0
-          || (pMem->flags&MEM_Null)==0 );
-  /* If the MEM is both real and integer, the values are equal */
-  assert( (pMem->flags & (MEM_Int|MEM_Real))!=(MEM_Int|MEM_Real) 
-          || pMem->r==pMem->u.i );
-}
-#endif
-
 /* This function is only available internally, it is not part of the
 ** external API. It works in a similar way to sqlite3_value_text(),
 ** except the data returned is in the encoding specified by the second
@@ -44675,7 +57929,7 @@ SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
   }
   assert( (MEM_Blob>>3) == MEM_Str );
   pVal->flags |= (pVal->flags & MEM_Blob)>>3;
-  expandBlob(pVal);
+  ExpandBlob(pVal);
   if( pVal->flags&MEM_Str ){
     sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
     if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
@@ -44684,7 +57938,7 @@ SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
         return 0;
       }
     }
-    sqlite3VdbeMemNulTerminate(pVal);
+    sqlite3VdbeMemNulTerminate(pVal); /* IMP: R-31275-44060 */
   }else{
     assert( (pVal->flags&MEM_Blob)==0 );
     sqlite3VdbeMemStringify(pVal, enc);
@@ -44732,6 +57986,8 @@ SQLITE_PRIVATE int sqlite3ValueFromExpr(
   int op;
   char *zVal = 0;
   sqlite3_value *pVal = 0;
+  int negInt = 1;
+  const char *zNeg = "";
 
   if( !pExpr ){
     *ppVal = 0;
@@ -44739,39 +57995,83 @@ SQLITE_PRIVATE int sqlite3ValueFromExpr(
   }
   op = pExpr->op;
 
+  /* op can only be TK_REGISTER if we have compiled with SQLITE_ENABLE_STAT3.
+  ** The ifdef here is to enable us to achieve 100% branch test coverage even
+  ** when SQLITE_ENABLE_STAT3 is omitted.
+  */
+#ifdef SQLITE_ENABLE_STAT3
+  if( op==TK_REGISTER ) op = pExpr->op2;
+#else
+  if( NEVER(op==TK_REGISTER) ) op = pExpr->op2;
+#endif
+
+  /* Handle negative integers in a single step.  This is needed in the
+  ** case when the value is -9223372036854775808.
+  */
+  if( op==TK_UMINUS
+   && (pExpr->pLeft->op==TK_INTEGER || pExpr->pLeft->op==TK_FLOAT) ){
+    pExpr = pExpr->pLeft;
+    op = pExpr->op;
+    negInt = -1;
+    zNeg = "-";
+  }
+
   if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
-    zVal = sqlite3DbStrNDup(db, (char*)pExpr->token.z, pExpr->token.n);
     pVal = sqlite3ValueNew(db);
-    if( !zVal || !pVal ) goto no_mem;
-    sqlite3Dequote(zVal);
-    sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
-    if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
-      sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, enc);
+    if( pVal==0 ) goto no_mem;
+    if( ExprHasProperty(pExpr, EP_IntValue) ){
+      sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
     }else{
-      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+      zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
+      if( zVal==0 ) goto no_mem;
+      sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
+      if( op==TK_FLOAT ) pVal->type = SQLITE_FLOAT;
+    }
+    if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
+      sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
+    }else{
+      sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
+    }
+    if( pVal->flags & (MEM_Int|MEM_Real) ) pVal->flags &= ~MEM_Str;
+    if( enc!=SQLITE_UTF8 ){
+      sqlite3VdbeChangeEncoding(pVal, enc);
     }
   }else if( op==TK_UMINUS ) {
+    /* This branch happens for multiple negative signs.  Ex: -(-5) */
     if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
-      pVal->u.i = -1 * pVal->u.i;
-      pVal->r = -1.0 * pVal->r;
+      sqlite3VdbeMemNumerify(pVal);
+      if( pVal->u.i==SMALLEST_INT64 ){
+        pVal->flags &= MEM_Int;
+        pVal->flags |= MEM_Real;
+        pVal->r = (double)LARGEST_INT64;
+      }else{
+        pVal->u.i = -pVal->u.i;
+      }
+      pVal->r = -pVal->r;
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
     }
+  }else if( op==TK_NULL ){
+    pVal = sqlite3ValueNew(db);
+    if( pVal==0 ) goto no_mem;
   }
 #ifndef SQLITE_OMIT_BLOB_LITERAL
   else if( op==TK_BLOB ){
     int nVal;
-    assert( pExpr->token.n>=3 );
-    assert( pExpr->token.z[0]=='x' || pExpr->token.z[0]=='X' );
-    assert( pExpr->token.z[1]=='\'' );
-    assert( pExpr->token.z[pExpr->token.n-1]=='\'' );
+    assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+    assert( pExpr->u.zToken[1]=='\'' );
     pVal = sqlite3ValueNew(db);
     if( !pVal ) goto no_mem;
-    nVal = pExpr->token.n - 3;
-    zVal = (char*)pExpr->token.z + 2;
+    zVal = &pExpr->u.zToken[2];
+    nVal = sqlite3Strlen30(zVal)-1;
+    assert( zVal[nVal]=='\'' );
     sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
                          0, SQLITE_DYNAMIC);
   }
 #endif
 
+  if( pVal ){
+    sqlite3VdbeMemStoreType(pVal);
+  }
   *ppVal = pVal;
   return SQLITE_OK;
 
@@ -44838,8 +58138,6 @@ SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
 ** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
 ** to version 2.8.7, all this code was combined into the vdbe.c source file.
 ** But that file was getting too big so this subroutines were split out.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
@@ -44875,17 +58173,23 @@ SQLITE_PRIVATE Vdbe *sqlite3VdbeCreate(sqlite3 *db){
 /*
 ** Remember the SQL string for a prepared statement.
 */
-SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n){
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n, int isPrepareV2){
+  assert( isPrepareV2==1 || isPrepareV2==0 );
   if( p==0 ) return;
+#ifdef SQLITE_OMIT_TRACE
+  if( !isPrepareV2 ) return;
+#endif
   assert( p->zSql==0 );
   p->zSql = sqlite3DbStrNDup(p->db, z, n);
+  p->isPrepareV2 = (u8)isPrepareV2;
 }
 
 /*
 ** Return the SQL associated with a prepared statement
 */
 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt){
-  return ((Vdbe *)pStmt)->zSql;
+  Vdbe *p = (Vdbe *)pStmt;
+  return (p && p->isPrepareV2) ? p->zSql : 0;
 }
 
 /*
@@ -44894,7 +58198,6 @@ SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt){
 SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){
   Vdbe tmp, *pTmp;
   char *zTmp;
-  int nTmp;
   tmp = *pA;
   *pA = *pB;
   *pB = tmp;
@@ -44907,9 +58210,7 @@ SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){
   zTmp = pA->zSql;
   pA->zSql = pB->zSql;
   pB->zSql = zTmp;
-  nTmp = pA->nSql;
-  pA->nSql = pB->nSql;
-  pB->nSql = nTmp;
+  pB->isPrepareV2 = pA->isPrepareV2;
 }
 
 #ifdef SQLITE_DEBUG
@@ -44935,7 +58236,7 @@ static int growOpArray(Vdbe *p){
   int nNew = (p->nOpAlloc ? p->nOpAlloc*2 : (int)(1024/sizeof(Op)));
   pNew = sqlite3DbRealloc(p->db, p->aOp, nNew*sizeof(Op));
   if( pNew ){
-    p->nOpAlloc = nNew;
+    p->nOpAlloc = sqlite3DbMallocSize(p->db, pNew)/sizeof(Op);
     p->aOp = pNew;
   }
   return (pNew ? SQLITE_OK : SQLITE_NOMEM);
@@ -44966,7 +58267,7 @@ SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
   assert( op>0 && op<0xff );
   if( p->nOpAlloc<=i ){
     if( growOpArray(p) ){
-      return 0;
+      return 1;
     }
   }
   p->nOp++;
@@ -44978,7 +58279,6 @@ SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
   pOp->p3 = p3;
   pOp->p4.p = 0;
   pOp->p4type = P4_NOTUSED;
-  p->expired = 0;
 #ifdef SQLITE_DEBUG
   pOp->zComment = 0;
   if( sqlite3VdbeAddopTrace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
@@ -45017,6 +58317,37 @@ SQLITE_PRIVATE int sqlite3VdbeAddOp4(
   return addr;
 }
 
+/*
+** Add an OP_ParseSchema opcode.  This routine is broken out from
+** sqlite3VdbeAddOp4() since it needs to also needs to mark all btrees
+** as having been used.
+**
+** The zWhere string must have been obtained from sqlite3_malloc().
+** This routine will take ownership of the allocated memory.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAddParseSchemaOp(Vdbe *p, int iDb, char *zWhere){
+  int j;
+  int addr = sqlite3VdbeAddOp3(p, OP_ParseSchema, iDb, 0, 0);
+  sqlite3VdbeChangeP4(p, addr, zWhere, P4_DYNAMIC);
+  for(j=0; j<p->db->nDb; j++) sqlite3VdbeUsesBtree(p, j);
+}
+
+/*
+** Add an opcode that includes the p4 value as an integer.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  int p4              /* The P4 operand as an integer */
+){
+  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+  sqlite3VdbeChangeP4(p, addr, SQLITE_INT_TO_PTR(p4), P4_INT32);
+  return addr;
+}
+
 /*
 ** Create a new symbolic label for an instruction that has yet to be
 ** coded.  The symbolic label is really just a negative number.  The
@@ -45032,14 +58363,11 @@ SQLITE_PRIVATE int sqlite3VdbeAddOp4(
 ** Zero is returned if a malloc() fails.
 */
 SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Vdbe *p){
-  int i;
-  i = p->nLabel++;
+  int i = p->nLabel++;
   assert( p->magic==VDBE_MAGIC_INIT );
-  if( i>=p->nLabelAlloc ){
-    int n = p->nLabelAlloc*2 + 5;
-    p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel,
-                                       n*sizeof(p->aLabel[0]));
-    p->nLabelAlloc = sqlite3DbMallocSize(p->db, p->aLabel)/sizeof(p->aLabel[0]);
+  if( (i & (i-1))==0 ){
+    p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel, 
+                                       (i*2+1)*sizeof(p->aLabel[0]));
   }
   if( p->aLabel ){
     p->aLabel[i] = -1;
@@ -45061,6 +58389,134 @@ SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe *p, int x){
   }
 }
 
+/*
+** Mark the VDBE as one that can only be run one time.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe *p){
+  p->runOnlyOnce = 1;
+}
+
+#ifdef SQLITE_DEBUG /* sqlite3AssertMayAbort() logic */
+
+/*
+** The following type and function are used to iterate through all opcodes
+** in a Vdbe main program and each of the sub-programs (triggers) it may 
+** invoke directly or indirectly. It should be used as follows:
+**
+**   Op *pOp;
+**   VdbeOpIter sIter;
+**
+**   memset(&sIter, 0, sizeof(sIter));
+**   sIter.v = v;                            // v is of type Vdbe* 
+**   while( (pOp = opIterNext(&sIter)) ){
+**     // Do something with pOp
+**   }
+**   sqlite3DbFree(v->db, sIter.apSub);
+** 
+*/
+typedef struct VdbeOpIter VdbeOpIter;
+struct VdbeOpIter {
+  Vdbe *v;                   /* Vdbe to iterate through the opcodes of */
+  SubProgram **apSub;        /* Array of subprograms */
+  int nSub;                  /* Number of entries in apSub */
+  int iAddr;                 /* Address of next instruction to return */
+  int iSub;                  /* 0 = main program, 1 = first sub-program etc. */
+};
+static Op *opIterNext(VdbeOpIter *p){
+  Vdbe *v = p->v;
+  Op *pRet = 0;
+  Op *aOp;
+  int nOp;
+
+  if( p->iSub<=p->nSub ){
+
+    if( p->iSub==0 ){
+      aOp = v->aOp;
+      nOp = v->nOp;
+    }else{
+      aOp = p->apSub[p->iSub-1]->aOp;
+      nOp = p->apSub[p->iSub-1]->nOp;
+    }
+    assert( p->iAddr<nOp );
+
+    pRet = &aOp[p->iAddr];
+    p->iAddr++;
+    if( p->iAddr==nOp ){
+      p->iSub++;
+      p->iAddr = 0;
+    }
+  
+    if( pRet->p4type==P4_SUBPROGRAM ){
+      int nByte = (p->nSub+1)*sizeof(SubProgram*);
+      int j;
+      for(j=0; j<p->nSub; j++){
+        if( p->apSub[j]==pRet->p4.pProgram ) break;
+      }
+      if( j==p->nSub ){
+        p->apSub = sqlite3DbReallocOrFree(v->db, p->apSub, nByte);
+        if( !p->apSub ){
+          pRet = 0;
+        }else{
+          p->apSub[p->nSub++] = pRet->p4.pProgram;
+        }
+      }
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** Check if the program stored in the VM associated with pParse may
+** throw an ABORT exception (causing the statement, but not entire transaction
+** to be rolled back). This condition is true if the main program or any
+** sub-programs contains any of the following:
+**
+**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_HaltIfNull with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_Destroy
+**   *  OP_VUpdate
+**   *  OP_VRename
+**   *  OP_FkCounter with P2==0 (immediate foreign key constraint)
+**
+** Then check that the value of Parse.mayAbort is true if an
+** ABORT may be thrown, or false otherwise. Return true if it does
+** match, or false otherwise. This function is intended to be used as
+** part of an assert statement in the compiler. Similar to:
+**
+**   assert( sqlite3VdbeAssertMayAbort(pParse->pVdbe, pParse->mayAbort) );
+*/
+SQLITE_PRIVATE int sqlite3VdbeAssertMayAbort(Vdbe *v, int mayAbort){
+  int hasAbort = 0;
+  Op *pOp;
+  VdbeOpIter sIter;
+  memset(&sIter, 0, sizeof(sIter));
+  sIter.v = v;
+
+  while( (pOp = opIterNext(&sIter))!=0 ){
+    int opcode = pOp->opcode;
+    if( opcode==OP_Destroy || opcode==OP_VUpdate || opcode==OP_VRename 
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+     || (opcode==OP_FkCounter && pOp->p1==0 && pOp->p2==1) 
+#endif
+     || ((opcode==OP_Halt || opcode==OP_HaltIfNull) 
+      && (pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort))
+    ){
+      hasAbort = 1;
+      break;
+    }
+  }
+  sqlite3DbFree(v->db, sIter.apSub);
+
+  /* Return true if hasAbort==mayAbort. Or if a malloc failure occured.
+  ** If malloc failed, then the while() loop above may not have iterated
+  ** through all opcodes and hasAbort may be set incorrectly. Return
+  ** true for this case to prevent the assert() in the callers frame
+  ** from failing.  */
+  return ( v->db->mallocFailed || hasAbort==mayAbort );
+}
+#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */
+
 /*
 ** Loop through the program looking for P2 values that are negative
 ** on jump instructions.  Each such value is a label.  Resolve the
@@ -45072,52 +58528,25 @@ SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe *p, int x){
 ** to an OP_Function, OP_AggStep or OP_VFilter opcode. This is used by 
 ** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
 **
-** This routine also does the following optimization:  It scans for
-** instructions that might cause a statement rollback.  Such instructions
-** are:
-**
-**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
-**   *  OP_Destroy
-**   *  OP_VUpdate
-**   *  OP_VRename
-**
-** If no such instruction is found, then every Statement instruction 
-** is changed to a Noop.  In this way, we avoid creating the statement 
-** journal file unnecessarily.
+** The Op.opflags field is set on all opcodes.
 */
 static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
   int i;
-  int nMaxArgs = 0;
+  int nMaxArgs = *pMaxFuncArgs;
   Op *pOp;
   int *aLabel = p->aLabel;
-  int doesStatementRollback = 0;
-  int hasStatementBegin = 0;
   p->readOnly = 1;
-  p->usesStmtJournal = 0;
   for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
     u8 opcode = pOp->opcode;
 
+    pOp->opflags = sqlite3OpcodeProperty[opcode];
     if( opcode==OP_Function || opcode==OP_AggStep ){
       if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;
+    }else if( (opcode==OP_Transaction && pOp->p2!=0) || opcode==OP_Vacuum ){
+      p->readOnly = 0;
 #ifndef SQLITE_OMIT_VIRTUALTABLE
     }else if( opcode==OP_VUpdate ){
       if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
-#endif
-    }
-    if( opcode==OP_Halt ){
-      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
-        doesStatementRollback = 1;
-      }
-    }else if( opcode==OP_Statement ){
-      hasStatementBegin = 1;
-      p->usesStmtJournal = 1;
-    }else if( opcode==OP_Destroy ){
-      doesStatementRollback = 1;
-    }else if( opcode==OP_Transaction && pOp->p2!=0 ){
-      p->readOnly = 0;
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-    }else if( opcode==OP_VUpdate || opcode==OP_VRename ){
-      doesStatementRollback = 1;
     }else if( opcode==OP_VFilter ){
       int n;
       assert( p->nOp - i >= 3 );
@@ -45125,9 +58554,15 @@ static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
       n = pOp[-1].p1;
       if( n>nMaxArgs ) nMaxArgs = n;
 #endif
+    }else if( opcode==OP_Next || opcode==OP_SorterNext ){
+      pOp->p4.xAdvance = sqlite3BtreeNext;
+      pOp->p4type = P4_ADVANCE;
+    }else if( opcode==OP_Prev ){
+      pOp->p4.xAdvance = sqlite3BtreePrevious;
+      pOp->p4type = P4_ADVANCE;
     }
 
-    if( sqlite3VdbeOpcodeHasProperty(opcode, OPFLG_JUMP) && pOp->p2<0 ){
+    if( (pOp->opflags & OPFLG_JUMP)!=0 && pOp->p2<0 ){
       assert( -1-pOp->p2<p->nLabel );
       pOp->p2 = aLabel[-1-pOp->p2];
     }
@@ -45136,20 +58571,6 @@ static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
   p->aLabel = 0;
 
   *pMaxFuncArgs = nMaxArgs;
-
-  /* If we never rollback a statement transaction, then statement
-  ** transactions are not needed.  So change every OP_Statement
-  ** opcode into an OP_Noop.  This avoid a call to sqlite3OsOpenExclusive()
-  ** which can be expensive on some platforms.
-  */
-  if( hasStatementBegin && !doesStatementRollback ){
-    p->usesStmtJournal = 0;
-    for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
-      if( pOp->opcode==OP_Statement ){
-        pOp->opcode = OP_Noop;
-      }
-    }
-  }
 }
 
 /*
@@ -45160,6 +58581,30 @@ SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe *p){
   return p->nOp;
 }
 
+/*
+** This function returns a pointer to the array of opcodes associated with
+** the Vdbe passed as the first argument. It is the callers responsibility
+** to arrange for the returned array to be eventually freed using the 
+** vdbeFreeOpArray() function.
+**
+** Before returning, *pnOp is set to the number of entries in the returned
+** array. Also, *pnMaxArg is set to the larger of its current value and 
+** the number of entries in the Vdbe.apArg[] array required to execute the 
+** returned program.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeTakeOpArray(Vdbe *p, int *pnOp, int *pnMaxArg){
+  VdbeOp *aOp = p->aOp;
+  assert( aOp && !p->db->mallocFailed );
+
+  /* Check that sqlite3VdbeUsesBtree() was not called on this VM */
+  assert( p->btreeMask==0 );
+
+  resolveP2Values(p, pnMaxArg);
+  *pnOp = p->nOp;
+  p->aOp = 0;
+  return aOp;
+}
+
 /*
 ** Add a whole list of operations to the operation stack.  Return the
 ** address of the first operation added.
@@ -45171,7 +58616,7 @@ SQLITE_PRIVATE int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp)
     return 0;
   }
   addr = p->nOp;
-  if( nOp>0 ){
+  if( ALWAYS(nOp>0) ){
     int i;
     VdbeOpList const *pIn = aOp;
     for(i=0; i<nOp; i++, pIn++){
@@ -45179,7 +58624,7 @@ SQLITE_PRIVATE int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp)
       VdbeOp *pOut = &p->aOp[i+addr];
       pOut->opcode = pIn->opcode;
       pOut->p1 = pIn->p1;
-      if( p2<0 && sqlite3VdbeOpcodeHasProperty(pOut->opcode, OPFLG_JUMP) ){
+      if( p2<0 && (sqlite3OpcodeProperty[pOut->opcode] & OPFLG_JUMP)!=0 ){
         pOut->p2 = addr + ADDR(p2);
       }else{
         pOut->p2 = p2;
@@ -45206,9 +58651,9 @@ SQLITE_PRIVATE int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp)
 ** static array using sqlite3VdbeAddOpList but we want to make a
 ** few minor changes to the program.
 */
-SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){
-  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
-  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe *p, u32 addr, int val){
+  assert( p!=0 );
+  if( ((u32)p->nOp)>addr ){
     p->aOp[addr].p1 = val;
   }
 }
@@ -45217,9 +58662,9 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){
 ** Change the value of the P2 operand for a specific instruction.
 ** This routine is useful for setting a jump destination.
 */
-SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){
-  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
-  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe *p, u32 addr, int val){
+  assert( p!=0 );
+  if( ((u32)p->nOp)>addr ){
     p->aOp[addr].p2 = val;
   }
 }
@@ -45227,9 +58672,9 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){
 /*
 ** Change the value of the P3 operand for a specific instruction.
 */
-SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe *p, int addr, int val){
-  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
-  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe *p, u32 addr, int val){
+  assert( p!=0 );
+  if( ((u32)p->nOp)>addr ){
     p->aOp[addr].p3 = val;
   }
 }
@@ -45239,8 +58684,8 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe *p, int addr, int val){
 ** added operation.
 */
 SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe *p, u8 val){
-  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
-  if( p && p->aOp ){
+  assert( p!=0 );
+  if( p->aOp ){
     assert( p->nOp>0 );
     p->aOp[p->nOp-1].p5 = val;
   }
@@ -45251,7 +58696,8 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe *p, u8 val){
 ** the address of the next instruction to be coded.
 */
 SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe *p, int addr){
-  sqlite3VdbeChangeP2(p, addr, p->nOp);
+  assert( addr>=0 || p->db->mallocFailed );
+  if( addr>=0 ) sqlite3VdbeChangeP2(p, addr, p->nOp);
 }
 
 
@@ -45260,20 +58706,22 @@ SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe *p, int addr){
 ** the FuncDef is not ephermal, then do nothing.
 */
 static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
-  if( pDef && (pDef->flags & SQLITE_FUNC_EPHEM)!=0 ){
+  if( ALWAYS(pDef) && (pDef->flags & SQLITE_FUNC_EPHEM)!=0 ){
     sqlite3DbFree(db, pDef);
   }
 }
 
+static void vdbeFreeOpArray(sqlite3 *, Op *, int);
+
 /*
 ** Delete a P4 value if necessary.
 */
 static void freeP4(sqlite3 *db, int p4type, void *p4){
   if( p4 ){
+    assert( db );
     switch( p4type ){
       case P4_REAL:
       case P4_INT64:
-      case P4_MPRINTF:
       case P4_DYNAMIC:
       case P4_KEYINFO:
       case P4_INTARRAY:
@@ -45281,10 +58729,14 @@ static void freeP4(sqlite3 *db, int p4type, void *p4){
         sqlite3DbFree(db, p4);
         break;
       }
+      case P4_MPRINTF: {
+        if( db->pnBytesFreed==0 ) sqlite3_free(p4);
+        break;
+      }
       case P4_VDBEFUNC: {
         VdbeFunc *pVdbeFunc = (VdbeFunc *)p4;
         freeEphemeralFunction(db, pVdbeFunc->pFunc);
-        sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
+        if( db->pnBytesFreed==0 ) sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
         sqlite3DbFree(db, pVdbeFunc);
         break;
       }
@@ -45293,27 +58745,61 @@ static void freeP4(sqlite3 *db, int p4type, void *p4){
         break;
       }
       case P4_MEM: {
-        sqlite3ValueFree((sqlite3_value*)p4);
+        if( db->pnBytesFreed==0 ){
+          sqlite3ValueFree((sqlite3_value*)p4);
+        }else{
+          Mem *p = (Mem*)p4;
+          sqlite3DbFree(db, p->zMalloc);
+          sqlite3DbFree(db, p);
+        }
+        break;
+      }
+      case P4_VTAB : {
+        if( db->pnBytesFreed==0 ) sqlite3VtabUnlock((VTable *)p4);
         break;
       }
     }
   }
 }
 
+/*
+** Free the space allocated for aOp and any p4 values allocated for the
+** opcodes contained within. If aOp is not NULL it is assumed to contain 
+** nOp entries. 
+*/
+static void vdbeFreeOpArray(sqlite3 *db, Op *aOp, int nOp){
+  if( aOp ){
+    Op *pOp;
+    for(pOp=aOp; pOp<&aOp[nOp]; pOp++){
+      freeP4(db, pOp->p4type, pOp->p4.p);
+#ifdef SQLITE_DEBUG
+      sqlite3DbFree(db, pOp->zComment);
+#endif     
+    }
+  }
+  sqlite3DbFree(db, aOp);
+}
 
 /*
-** Change N opcodes starting at addr to No-ops.
+** Link the SubProgram object passed as the second argument into the linked
+** list at Vdbe.pSubProgram. This list is used to delete all sub-program
+** objects when the VM is no longer required.
 */
-SQLITE_PRIVATE void sqlite3VdbeChangeToNoop(Vdbe *p, int addr, int N){
-  if( p && p->aOp ){
+SQLITE_PRIVATE void sqlite3VdbeLinkSubProgram(Vdbe *pVdbe, SubProgram *p){
+  p->pNext = pVdbe->pProgram;
+  pVdbe->pProgram = p;
+}
+
+/*
+** Change the opcode at addr into OP_Noop
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeToNoop(Vdbe *p, int addr){
+  if( p->aOp ){
     VdbeOp *pOp = &p->aOp[addr];
     sqlite3 *db = p->db;
-    while( N-- ){
-      freeP4(db, pOp->p4type, pOp->p4.p);
-      memset(pOp, 0, sizeof(pOp[0]));
-      pOp->opcode = OP_Noop;
-      pOp++;
-    }
+    freeP4(db, pOp->p4type, pOp->p4.p);
+    memset(pOp, 0, sizeof(pOp[0]));
+    pOp->opcode = OP_Noop;
   }
 }
 
@@ -45349,15 +58835,15 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int
   db = p->db;
   assert( p->magic==VDBE_MAGIC_INIT );
   if( p->aOp==0 || db->mallocFailed ){
-    if (n != P4_KEYINFO) {
+    if ( n!=P4_KEYINFO && n!=P4_VTAB ) {
       freeP4(db, n, (void*)*(char**)&zP4);
     }
     return;
   }
+  assert( p->nOp>0 );
   assert( addr<p->nOp );
   if( addr<0 ){
     addr = p->nOp - 1;
-    if( addr<0 ) return;
   }
   pOp = &p->aOp[addr];
   freeP4(db, pOp->p4type, pOp->p4.p);
@@ -45376,11 +58862,11 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int
 
     nField = ((KeyInfo*)zP4)->nField;
     nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
-    pKeyInfo = sqlite3Malloc( nByte );
+    pKeyInfo = sqlite3DbMallocRaw(0, nByte);
     pOp->p4.pKeyInfo = pKeyInfo;
     if( pKeyInfo ){
       u8 *aSortOrder;
-      memcpy(pKeyInfo, zP4, nByte);
+      memcpy((char*)pKeyInfo, zP4, nByte - nField);
       aSortOrder = pKeyInfo->aSortOrder;
       if( aSortOrder ){
         pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
@@ -45394,6 +58880,11 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int
   }else if( n==P4_KEYINFO_HANDOFF ){
     pOp->p4.p = (void*)zP4;
     pOp->p4type = P4_KEYINFO;
+  }else if( n==P4_VTAB ){
+    pOp->p4.p = (void*)zP4;
+    pOp->p4type = P4_VTAB;
+    sqlite3VtabLock((VTable *)zP4);
+    assert( ((VTable *)zP4)->db==p->db );
   }else if( n<0 ){
     pOp->p4.p = (void*)zP4;
     pOp->p4type = (signed char)n;
@@ -45406,45 +58897,77 @@ SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int
 
 #ifndef NDEBUG
 /*
-** Change the comment on the the most recently coded instruction.  Or
+** Change the comment on the most recently coded instruction.  Or
 ** insert a No-op and add the comment to that new instruction.  This
 ** makes the code easier to read during debugging.  None of this happens
 ** in a production build.
 */
-SQLITE_PRIVATE void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
-  va_list ap;
+static void vdbeVComment(Vdbe *p, const char *zFormat, va_list ap){
   assert( p->nOp>0 || p->aOp==0 );
   assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
   if( p->nOp ){
-    char **pz = &p->aOp[p->nOp-1].zComment;
+    assert( p->aOp );
+    sqlite3DbFree(p->db, p->aOp[p->nOp-1].zComment);
+    p->aOp[p->nOp-1].zComment = sqlite3VMPrintf(p->db, zFormat, ap);
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  if( p ){
     va_start(ap, zFormat);
-    sqlite3DbFree(p->db, *pz);
-    *pz = sqlite3VMPrintf(p->db, zFormat, ap);
+    vdbeVComment(p, zFormat, ap);
     va_end(ap);
   }
 }
 SQLITE_PRIVATE void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
   va_list ap;
-  sqlite3VdbeAddOp0(p, OP_Noop);
-  assert( p->nOp>0 || p->aOp==0 );
-  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
-  if( p->nOp ){
-    char **pz = &p->aOp[p->nOp-1].zComment;
+  if( p ){
+    sqlite3VdbeAddOp0(p, OP_Noop);
     va_start(ap, zFormat);
-    sqlite3DbFree(p->db, *pz);
-    *pz = sqlite3VMPrintf(p->db, zFormat, ap);
+    vdbeVComment(p, zFormat, ap);
     va_end(ap);
   }
 }
 #endif  /* NDEBUG */
 
 /*
-** Return the opcode for a given address.
+** Return the opcode for a given address.  If the address is -1, then
+** return the most recently inserted opcode.
+**
+** If a memory allocation error has occurred prior to the calling of this
+** routine, then a pointer to a dummy VdbeOp will be returned.  That opcode
+** is readable but not writable, though it is cast to a writable value.
+** The return of a dummy opcode allows the call to continue functioning
+** after a OOM fault without having to check to see if the return from 
+** this routine is a valid pointer.  But because the dummy.opcode is 0,
+** dummy will never be written to.  This is verified by code inspection and
+** by running with Valgrind.
+**
+** About the #ifdef SQLITE_OMIT_TRACE:  Normally, this routine is never called
+** unless p->nOp>0.  This is because in the absense of SQLITE_OMIT_TRACE,
+** an OP_Trace instruction is always inserted by sqlite3VdbeGet() as soon as
+** a new VDBE is created.  So we are free to set addr to p->nOp-1 without
+** having to double-check to make sure that the result is non-negative. But
+** if SQLITE_OMIT_TRACE is defined, the OP_Trace is omitted and we do need to
+** check the value of p->nOp-1 before continuing.
 */
 SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
+  /* C89 specifies that the constant "dummy" will be initialized to all
+  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
+  static VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
   assert( p->magic==VDBE_MAGIC_INIT );
+  if( addr<0 ){
+#ifdef SQLITE_OMIT_TRACE
+    if( p->nOp==0 ) return (VdbeOp*)&dummy;
+#endif
+    addr = p->nOp - 1;
+  }
   assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
-  return ((addr>=0 && addr<p->nOp)?(&p->aOp[addr]):0);
+  if( p->db->mallocFailed ){
+    return (VdbeOp*)&dummy;
+  }else{
+    return &p->aOp[addr];
+  }
 }
 
 #if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
@@ -45511,19 +59034,23 @@ static char *displayP4(Op *pOp, char *zTemp, int nTemp){
     }
     case P4_MEM: {
       Mem *pMem = pOp->p4.pMem;
-      assert( (pMem->flags & MEM_Null)==0 );
       if( pMem->flags & MEM_Str ){
         zP4 = pMem->z;
       }else if( pMem->flags & MEM_Int ){
         sqlite3_snprintf(nTemp, zTemp, "%lld", pMem->u.i);
       }else if( pMem->flags & MEM_Real ){
         sqlite3_snprintf(nTemp, zTemp, "%.16g", pMem->r);
+      }else if( pMem->flags & MEM_Null ){
+        sqlite3_snprintf(nTemp, zTemp, "NULL");
+      }else{
+        assert( pMem->flags & MEM_Blob );
+        zP4 = "(blob)";
       }
       break;
     }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
     case P4_VTAB: {
-      sqlite3_vtab *pVtab = pOp->p4.pVtab;
+      sqlite3_vtab *pVtab = pOp->p4.pVtab->pVtab;
       sqlite3_snprintf(nTemp, zTemp, "vtab:%p:%p", pVtab, pVtab->pModule);
       break;
     }
@@ -45532,6 +59059,14 @@ static char *displayP4(Op *pOp, char *zTemp, int nTemp){
       sqlite3_snprintf(nTemp, zTemp, "intarray");
       break;
     }
+    case P4_SUBPROGRAM: {
+      sqlite3_snprintf(nTemp, zTemp, "program");
+      break;
+    }
+    case P4_ADVANCE: {
+      zTemp[0] = 0;
+      break;
+    }
     default: {
       zP4 = pOp->p4.z;
       if( zP4==0 ){
@@ -45548,18 +59083,81 @@ static char *displayP4(Op *pOp, char *zTemp, int nTemp){
 /*
 ** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
 **
+** The prepared statements need to know in advance the complete set of
+** attached databases that will be use.  A mask of these databases
+** is maintained in p->btreeMask.  The p->lockMask value is the subset of
+** p->btreeMask of databases that will require a lock.
 */
 SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe *p, int i){
-  int mask;
-  assert( i>=0 && i<p->db->nDb );
+  assert( i>=0 && i<p->db->nDb && i<(int)sizeof(yDbMask)*8 );
   assert( i<(int)sizeof(p->btreeMask)*8 );
-  mask = 1<<i;
-  if( (p->btreeMask & mask)==0 ){
-    p->btreeMask |= mask;
-    sqlite3BtreeMutexArrayInsert(&p->aMutex, p->db->aDb[i].pBt);
+  p->btreeMask |= ((yDbMask)1)<<i;
+  if( i!=1 && sqlite3BtreeSharable(p->db->aDb[i].pBt) ){
+    p->lockMask |= ((yDbMask)1)<<i;
   }
 }
 
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
+/*
+** If SQLite is compiled to support shared-cache mode and to be threadsafe,
+** this routine obtains the mutex associated with each BtShared structure
+** that may be accessed by the VM passed as an argument. In doing so it also
+** sets the BtShared.db member of each of the BtShared structures, ensuring
+** that the correct busy-handler callback is invoked if required.
+**
+** If SQLite is not threadsafe but does support shared-cache mode, then
+** sqlite3BtreeEnter() is invoked to set the BtShared.db variables
+** of all of BtShared structures accessible via the database handle 
+** associated with the VM.
+**
+** If SQLite is not threadsafe and does not support shared-cache mode, this
+** function is a no-op.
+**
+** The p->btreeMask field is a bitmask of all btrees that the prepared 
+** statement p will ever use.  Let N be the number of bits in p->btreeMask
+** corresponding to btrees that use shared cache.  Then the runtime of
+** this routine is N*N.  But as N is rarely more than 1, this should not
+** be a problem.
+*/
+SQLITE_PRIVATE void sqlite3VdbeEnter(Vdbe *p){
+  int i;
+  yDbMask mask;
+  sqlite3 *db;
+  Db *aDb;
+  int nDb;
+  if( p->lockMask==0 ) return;  /* The common case */
+  db = p->db;
+  aDb = db->aDb;
+  nDb = db->nDb;
+  for(i=0, mask=1; i<nDb; i++, mask += mask){
+    if( i!=1 && (mask & p->lockMask)!=0 && ALWAYS(aDb[i].pBt!=0) ){
+      sqlite3BtreeEnter(aDb[i].pBt);
+    }
+  }
+}
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
+/*
+** Unlock all of the btrees previously locked by a call to sqlite3VdbeEnter().
+*/
+SQLITE_PRIVATE void sqlite3VdbeLeave(Vdbe *p){
+  int i;
+  yDbMask mask;
+  sqlite3 *db;
+  Db *aDb;
+  int nDb;
+  if( p->lockMask==0 ) return;  /* The common case */
+  db = p->db;
+  aDb = db->aDb;
+  nDb = db->nDb;
+  for(i=0, mask=1; i<nDb; i++, mask += mask){
+    if( i!=1 && (mask & p->lockMask)!=0 && ALWAYS(aDb[i].pBt!=0) ){
+      sqlite3BtreeLeave(aDb[i].pBt);
+    }
+  }
+}
+#endif
 
 #if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
 /*
@@ -45591,6 +59189,12 @@ static void releaseMemArray(Mem *p, int N){
     Mem *pEnd;
     sqlite3 *db = p->db;
     u8 malloc_failed = db->mallocFailed;
+    if( db->pnBytesFreed ){
+      for(pEnd=&p[N]; p<pEnd; p++){
+        sqlite3DbFree(db, p->zMalloc);
+      }
+      return;
+    }
     for(pEnd=&p[N]; p<pEnd; p++){
       assert( (&p[1])==pEnd || p[0].db==p[1].db );
 
@@ -45606,38 +59210,33 @@ static void releaseMemArray(Mem *p, int N){
       ** with no indexes using a single prepared INSERT statement, bind() 
       ** and reset(). Inserts are grouped into a transaction.
       */
-      if( p->flags&(MEM_Agg|MEM_Dyn) ){
+      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
         sqlite3VdbeMemRelease(p);
       }else if( p->zMalloc ){
         sqlite3DbFree(db, p->zMalloc);
         p->zMalloc = 0;
       }
 
-      p->flags = MEM_Null;
+      p->flags = MEM_Invalid;
     }
     db->mallocFailed = malloc_failed;
   }
 }
 
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
-SQLITE_PRIVATE int sqlite3VdbeReleaseBuffers(Vdbe *p){
-  int ii;
-  int nFree = 0;
-  assert( sqlite3_mutex_held(p->db->mutex) );
-  for(ii=1; ii<=p->nMem; ii++){
-    Mem *pMem = &p->aMem[ii];
-    if( pMem->flags & MEM_RowSet ){
-      sqlite3RowSetClear(pMem->u.pRowSet);
-    }
-    if( pMem->z && pMem->flags&MEM_Dyn ){
-      assert( !pMem->xDel );
-      nFree += sqlite3DbMallocSize(pMem->db, pMem->z);
-      sqlite3VdbeMemRelease(pMem);
-    }
+/*
+** Delete a VdbeFrame object and its contents. VdbeFrame objects are
+** allocated by the OP_Program opcode in sqlite3VdbeExec().
+*/
+SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame *p){
+  int i;
+  Mem *aMem = VdbeFrameMem(p);
+  VdbeCursor **apCsr = (VdbeCursor **)&aMem[p->nChildMem];
+  for(i=0; i<p->nChildCsr; i++){
+    sqlite3VdbeFreeCursor(p->v, apCsr[i]);
   }
-  return nFree;
+  releaseMemArray(aMem, p->nChildMem);
+  sqlite3DbFree(p->v->db, p);
 }
-#endif
 
 #ifndef SQLITE_OMIT_EXPLAIN
 /*
@@ -45651,25 +59250,32 @@ SQLITE_PRIVATE int sqlite3VdbeReleaseBuffers(Vdbe *p){
 ** p->explain==2, only OP_Explain instructions are listed and these
 ** are shown in a different format.  p->explain==2 is used to implement
 ** EXPLAIN QUERY PLAN.
+**
+** When p->explain==1, first the main program is listed, then each of
+** the trigger subprograms are listed one by one.
 */
 SQLITE_PRIVATE int sqlite3VdbeList(
   Vdbe *p                   /* The VDBE */
 ){
-  sqlite3 *db = p->db;
-  int i;
-  int rc = SQLITE_OK;
-  Mem *pMem = p->pResultSet = &p->aMem[1];
+  int nRow;                            /* Stop when row count reaches this */
+  int nSub = 0;                        /* Number of sub-vdbes seen so far */
+  SubProgram **apSub = 0;              /* Array of sub-vdbes */
+  Mem *pSub = 0;                       /* Memory cell hold array of subprogs */
+  sqlite3 *db = p->db;                 /* The database connection */
+  int i;                               /* Loop counter */
+  int rc = SQLITE_OK;                  /* Return code */
+  Mem *pMem = &p->aMem[1];             /* First Mem of result set */
 
   assert( p->explain );
-  if( p->magic!=VDBE_MAGIC_RUN ) return SQLITE_MISUSE;
-  assert( db->magic==SQLITE_MAGIC_BUSY );
+  assert( p->magic==VDBE_MAGIC_RUN );
   assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY || p->rc==SQLITE_NOMEM );
 
   /* Even though this opcode does not use dynamic strings for
   ** the result, result columns may become dynamic if the user calls
   ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
   */
-  releaseMemArray(pMem, p->nMem);
+  releaseMemArray(pMem, 8);
+  p->pResultSet = 0;
 
   if( p->rc==SQLITE_NOMEM ){
     /* This happens if a malloc() inside a call to sqlite3_column_text() or
@@ -45678,10 +59284,36 @@ SQLITE_PRIVATE int sqlite3VdbeList(
     return SQLITE_ERROR;
   }
 
+  /* When the number of output rows reaches nRow, that means the
+  ** listing has finished and sqlite3_step() should return SQLITE_DONE.
+  ** nRow is the sum of the number of rows in the main program, plus
+  ** the sum of the number of rows in all trigger subprograms encountered
+  ** so far.  The nRow value will increase as new trigger subprograms are
+  ** encountered, but p->pc will eventually catch up to nRow.
+  */
+  nRow = p->nOp;
+  if( p->explain==1 ){
+    /* The first 8 memory cells are used for the result set.  So we will
+    ** commandeer the 9th cell to use as storage for an array of pointers
+    ** to trigger subprograms.  The VDBE is guaranteed to have at least 9
+    ** cells.  */
+    assert( p->nMem>9 );
+    pSub = &p->aMem[9];
+    if( pSub->flags&MEM_Blob ){
+      /* On the first call to sqlite3_step(), pSub will hold a NULL.  It is
+      ** initialized to a BLOB by the P4_SUBPROGRAM processing logic below */
+      nSub = pSub->n/sizeof(Vdbe*);
+      apSub = (SubProgram **)pSub->z;
+    }
+    for(i=0; i<nSub; i++){
+      nRow += apSub[i]->nOp;
+    }
+  }
+
   do{
     i = p->pc++;
-  }while( i<p->nOp && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
-  if( i>=p->nOp ){
+  }while( i<nRow && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
+  if( i>=nRow ){
     p->rc = SQLITE_OK;
     rc = SQLITE_DONE;
   }else if( db->u1.isInterrupted ){
@@ -45690,7 +59322,21 @@ SQLITE_PRIVATE int sqlite3VdbeList(
     sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3ErrStr(p->rc));
   }else{
     char *z;
-    Op *pOp = &p->aOp[i];
+    Op *pOp;
+    if( i<p->nOp ){
+      /* The output line number is small enough that we are still in the
+      ** main program. */
+      pOp = &p->aOp[i];
+    }else{
+      /* We are currently listing subprograms.  Figure out which one and
+      ** pick up the appropriate opcode. */
+      int j;
+      i -= p->nOp;
+      for(j=0; i>=apSub[j]->nOp; j++){
+        i -= apSub[j]->nOp;
+      }
+      pOp = &apSub[j]->aOp[i];
+    }
     if( p->explain==1 ){
       pMem->flags = MEM_Int;
       pMem->type = SQLITE_INTEGER;
@@ -45704,6 +59350,25 @@ SQLITE_PRIVATE int sqlite3VdbeList(
       pMem->type = SQLITE_TEXT;
       pMem->enc = SQLITE_UTF8;
       pMem++;
+
+      /* When an OP_Program opcode is encounter (the only opcode that has
+      ** a P4_SUBPROGRAM argument), expand the size of the array of subprograms
+      ** kept in p->aMem[9].z to hold the new program - assuming this subprogram
+      ** has not already been seen.
+      */
+      if( pOp->p4type==P4_SUBPROGRAM ){
+        int nByte = (nSub+1)*sizeof(SubProgram*);
+        int j;
+        for(j=0; j<nSub; j++){
+          if( apSub[j]==pOp->p4.pProgram ) break;
+        }
+        if( j==nSub && SQLITE_OK==sqlite3VdbeMemGrow(pSub, nByte, nSub!=0) ){
+          apSub = (SubProgram **)pSub->z;
+          apSub[nSub++] = pOp->p4.pProgram;
+          pSub->flags |= MEM_Blob;
+          pSub->n = nSub*sizeof(SubProgram*);
+        }
+      }
     }
 
     pMem->flags = MEM_Int;
@@ -45716,16 +59381,14 @@ SQLITE_PRIVATE int sqlite3VdbeList(
     pMem->type = SQLITE_INTEGER;
     pMem++;
 
-    if( p->explain==1 ){
-      pMem->flags = MEM_Int;
-      pMem->u.i = pOp->p3;                          /* P3 */
-      pMem->type = SQLITE_INTEGER;
-      pMem++;
-    }
+    pMem->flags = MEM_Int;
+    pMem->u.i = pOp->p3;                          /* P3 */
+    pMem->type = SQLITE_INTEGER;
+    pMem++;
 
     if( sqlite3VdbeMemGrow(pMem, 32, 0) ){            /* P4 */
-      p->db->mallocFailed = 1;
-      return SQLITE_NOMEM;
+      assert( p->db->mallocFailed );
+      return SQLITE_ERROR;
     }
     pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
     z = displayP4(pOp, pMem->z, 32);
@@ -45741,8 +59404,8 @@ SQLITE_PRIVATE int sqlite3VdbeList(
 
     if( p->explain==1 ){
       if( sqlite3VdbeMemGrow(pMem, 4, 0) ){
-        p->db->mallocFailed = 1;
-        return SQLITE_NOMEM;
+        assert( p->db->mallocFailed );
+        return SQLITE_ERROR;
       }
       pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
       pMem->n = 2;
@@ -45766,7 +59429,8 @@ SQLITE_PRIVATE int sqlite3VdbeList(
       }
     }
 
-    p->nResColumn = 8 - 5*(p->explain-1);
+    p->nResColumn = 8 - 4*(p->explain-1);
+    p->pResultSet = &p->aMem[1];
     p->rc = SQLITE_OK;
     rc = SQLITE_ROW;
   }
@@ -45785,7 +59449,7 @@ SQLITE_PRIVATE void sqlite3VdbePrintSql(Vdbe *p){
   pOp = &p->aOp[0];
   if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
     const char *z = pOp->p4.z;
-    while( isspace(*(u8*)z) ) z++;
+    while( sqlite3Isspace(*z) ) z++;
     printf("SQL: [%s]\n", z);
   }
 }
@@ -45805,9 +59469,9 @@ SQLITE_PRIVATE void sqlite3VdbeIOTraceSql(Vdbe *p){
     int i, j;
     char z[1000];
     sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
-    for(i=0; isspace((unsigned char)z[i]); i++){}
+    for(i=0; sqlite3Isspace(z[i]); i++){}
     for(j=0; z[i]; i++){
-      if( isspace((unsigned char)z[i]) ){
+      if( sqlite3Isspace(z[i]) ){
         if( z[i-1]!=' ' ){
           z[j++] = ' ';
         }
@@ -45821,26 +59485,54 @@ SQLITE_PRIVATE void sqlite3VdbeIOTraceSql(Vdbe *p){
 }
 #endif /* !SQLITE_OMIT_TRACE && SQLITE_ENABLE_IOTRACE */
 
+/*
+** Allocate space from a fixed size buffer and return a pointer to
+** that space.  If insufficient space is available, return NULL.
+**
+** The pBuf parameter is the initial value of a pointer which will
+** receive the new memory.  pBuf is normally NULL.  If pBuf is not
+** NULL, it means that memory space has already been allocated and that
+** this routine should not allocate any new memory.  When pBuf is not
+** NULL simply return pBuf.  Only allocate new memory space when pBuf
+** is NULL.
+**
+** nByte is the number of bytes of space needed.
+**
+** *ppFrom points to available space and pEnd points to the end of the
+** available space.  When space is allocated, *ppFrom is advanced past
+** the end of the allocated space.
+**
+** *pnByte is a counter of the number of bytes of space that have failed
+** to allocate.  If there is insufficient space in *ppFrom to satisfy the
+** request, then increment *pnByte by the amount of the request.
+*/
+static void *allocSpace(
+  void *pBuf,          /* Where return pointer will be stored */
+  int nByte,           /* Number of bytes to allocate */
+  u8 **ppFrom,         /* IN/OUT: Allocate from *ppFrom */
+  u8 *pEnd,            /* Pointer to 1 byte past the end of *ppFrom buffer */
+  int *pnByte          /* If allocation cannot be made, increment *pnByte */
+){
+  assert( EIGHT_BYTE_ALIGNMENT(*ppFrom) );
+  if( pBuf ) return pBuf;
+  nByte = ROUND8(nByte);
+  if( &(*ppFrom)[nByte] <= pEnd ){
+    pBuf = (void*)*ppFrom;
+    *ppFrom += nByte;
+  }else{
+    *pnByte += nByte;
+  }
+  return pBuf;
+}
 
 /*
-** Prepare a virtual machine for execution.  This involves things such
-** as allocating stack space and initializing the program counter.
-** After the VDBE has be prepped, it can be executed by one or more
-** calls to sqlite3VdbeExec().  
-**
-** This is the only way to move a VDBE from VDBE_MAGIC_INIT to
-** VDBE_MAGIC_RUN.
+** Rewind the VDBE back to the beginning in preparation for
+** running it.
 */
-SQLITE_PRIVATE void sqlite3VdbeMakeReady(
-  Vdbe *p,                       /* The VDBE */
-  int nVar,                      /* Number of '?' see in the SQL statement */
-  int nMem,                      /* Number of memory cells to allocate */
-  int nCursor,                   /* Number of cursors to allocate */
-  int isExplain                  /* True if the EXPLAIN keywords is present */
-){
-  int n;
-  sqlite3 *db = p->db;
-
+SQLITE_PRIVATE void sqlite3VdbeRewind(Vdbe *p){
+#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
+  int i;
+#endif
   assert( p!=0 );
   assert( p->magic==VDBE_MAGIC_INIT );
 
@@ -45851,6 +59543,74 @@ SQLITE_PRIVATE void sqlite3VdbeMakeReady(
   /* Set the magic to VDBE_MAGIC_RUN sooner rather than later. */
   p->magic = VDBE_MAGIC_RUN;
 
+#ifdef SQLITE_DEBUG
+  for(i=1; i<p->nMem; i++){
+    assert( p->aMem[i].db==p->db );
+  }
+#endif
+  p->pc = -1;
+  p->rc = SQLITE_OK;
+  p->errorAction = OE_Abort;
+  p->magic = VDBE_MAGIC_RUN;
+  p->nChange = 0;
+  p->cacheCtr = 1;
+  p->minWriteFileFormat = 255;
+  p->iStatement = 0;
+  p->nFkConstraint = 0;
+#ifdef VDBE_PROFILE
+  for(i=0; i<p->nOp; i++){
+    p->aOp[i].cnt = 0;
+    p->aOp[i].cycles = 0;
+  }
+#endif
+}
+
+/*
+** Prepare a virtual machine for execution for the first time after
+** creating the virtual machine.  This involves things such
+** as allocating stack space and initializing the program counter.
+** After the VDBE has be prepped, it can be executed by one or more
+** calls to sqlite3VdbeExec().  
+**
+** This function may be called exact once on a each virtual machine.
+** After this routine is called the VM has been "packaged" and is ready
+** to run.  After this routine is called, futher calls to 
+** sqlite3VdbeAddOp() functions are prohibited.  This routine disconnects
+** the Vdbe from the Parse object that helped generate it so that the
+** the Vdbe becomes an independent entity and the Parse object can be
+** destroyed.
+**
+** Use the sqlite3VdbeRewind() procedure to restore a virtual machine back
+** to its initial state after it has been run.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(
+  Vdbe *p,                       /* The VDBE */
+  Parse *pParse                  /* Parsing context */
+){
+  sqlite3 *db;                   /* The database connection */
+  int nVar;                      /* Number of parameters */
+  int nMem;                      /* Number of VM memory registers */
+  int nCursor;                   /* Number of cursors required */
+  int nArg;                      /* Number of arguments in subprograms */
+  int nOnce;                     /* Number of OP_Once instructions */
+  int n;                         /* Loop counter */
+  u8 *zCsr;                      /* Memory available for allocation */
+  u8 *zEnd;                      /* First byte past allocated memory */
+  int nByte;                     /* How much extra memory is needed */
+
+  assert( p!=0 );
+  assert( p->nOp>0 );
+  assert( pParse!=0 );
+  assert( p->magic==VDBE_MAGIC_INIT );
+  db = p->db;
+  assert( db->mallocFailed==0 );
+  nVar = pParse->nVar;
+  nMem = pParse->nMem;
+  nCursor = pParse->nTab;
+  nArg = pParse->nMaxArg;
+  nOnce = pParse->nOnce;
+  if( nOnce==0 ) nOnce = 1; /* Ensure at least one byte in p->aOnceFlag[] */
+  
   /* For each cursor required, also allocate a memory cell. Memory
   ** cells (nMem+1-nCursor)..nMem, inclusive, will never be used by
   ** the vdbe program. Instead they are used to allocate space for
@@ -45862,68 +59622,72 @@ SQLITE_PRIVATE void sqlite3VdbeMakeReady(
   */
   nMem += nCursor;
 
-  /*
-  ** Allocation space for registers.
+  /* Allocate space for memory registers, SQL variables, VDBE cursors and 
+  ** an array to marshal SQL function arguments in.
   */
-  if( p->aMem==0 ){
-    int nArg;       /* Maximum number of args passed to a user function. */
-    resolveP2Values(p, &nArg);
-    assert( nVar>=0 );
-    if( isExplain && nMem<10 ){
-      nMem = 10;
-    }
-    p->aMem = sqlite3DbMallocZero(db,
-        nMem*sizeof(Mem)               /* aMem */
-      + nVar*sizeof(Mem)               /* aVar */
-      + nArg*sizeof(Mem*)              /* apArg */
-      + nVar*sizeof(char*)             /* azVar */
-      + nCursor*sizeof(VdbeCursor*)+1  /* apCsr */
-    );
-    if( !db->mallocFailed ){
-      p->aMem--;             /* aMem[] goes from 1..nMem */
-      p->nMem = nMem;        /*       not from 0..nMem-1 */
-      p->aVar = &p->aMem[nMem+1];
-      p->nVar = nVar;
-      p->okVar = 0;
-      p->apArg = (Mem**)&p->aVar[nVar];
-      p->azVar = (char**)&p->apArg[nArg];
-      p->apCsr = (VdbeCursor**)&p->azVar[nVar];
-      p->nCursor = nCursor;
-      for(n=0; n<nVar; n++){
-        p->aVar[n].flags = MEM_Null;
-        p->aVar[n].db = db;
-      }
-      for(n=1; n<=nMem; n++){
-        p->aMem[n].flags = MEM_Null;
-        p->aMem[n].db = db;
-      }
-    }
-  }
-#ifdef SQLITE_DEBUG
-  for(n=1; n<p->nMem; n++){
-    assert( p->aMem[n].db==db );
-  }
-#endif
+  zCsr = (u8*)&p->aOp[p->nOp];       /* Memory avaliable for allocation */
+  zEnd = (u8*)&p->aOp[p->nOpAlloc];  /* First byte past end of zCsr[] */
 
-  p->pc = -1;
-  p->rc = SQLITE_OK;
-  p->uniqueCnt = 0;
-  p->errorAction = OE_Abort;
-  p->explain |= isExplain;
-  p->magic = VDBE_MAGIC_RUN;
-  p->nChange = 0;
-  p->cacheCtr = 1;
-  p->minWriteFileFormat = 255;
-  p->openedStatement = 0;
-#ifdef VDBE_PROFILE
-  {
-    int i;
-    for(i=0; i<p->nOp; i++){
-      p->aOp[i].cnt = 0;
-      p->aOp[i].cycles = 0;
+  resolveP2Values(p, &nArg);
+  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
+  if( pParse->explain && nMem<10 ){
+    nMem = 10;
+  }
+  memset(zCsr, 0, zEnd-zCsr);
+  zCsr += (zCsr - (u8*)0)&7;
+  assert( EIGHT_BYTE_ALIGNMENT(zCsr) );
+  p->expired = 0;
+
+  /* Memory for registers, parameters, cursor, etc, is allocated in two
+  ** passes.  On the first pass, we try to reuse unused space at the 
+  ** end of the opcode array.  If we are unable to satisfy all memory
+  ** requirements by reusing the opcode array tail, then the second
+  ** pass will fill in the rest using a fresh allocation.  
+  **
+  ** This two-pass approach that reuses as much memory as possible from
+  ** the leftover space at the end of the opcode array can significantly
+  ** reduce the amount of memory held by a prepared statement.
+  */
+  do {
+    nByte = 0;
+    p->aMem = allocSpace(p->aMem, nMem*sizeof(Mem), &zCsr, zEnd, &nByte);
+    p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), &zCsr, zEnd, &nByte);
+    p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), &zCsr, zEnd, &nByte);
+    p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), &zCsr, zEnd, &nByte);
+    p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
+                          &zCsr, zEnd, &nByte);
+    p->aOnceFlag = allocSpace(p->aOnceFlag, nOnce, &zCsr, zEnd, &nByte);
+    if( nByte ){
+      p->pFree = sqlite3DbMallocZero(db, nByte);
+    }
+    zCsr = p->pFree;
+    zEnd = &zCsr[nByte];
+  }while( nByte && !db->mallocFailed );
+
+  p->nCursor = (u16)nCursor;
+  p->nOnceFlag = nOnce;
+  if( p->aVar ){
+    p->nVar = (ynVar)nVar;
+    for(n=0; n<nVar; n++){
+      p->aVar[n].flags = MEM_Null;
+      p->aVar[n].db = db;
     }
   }
-#endif
+  if( p->azVar ){
+    p->nzVar = pParse->nzVar;
+    memcpy(p->azVar, pParse->azVar, p->nzVar*sizeof(p->azVar[0]));
+    memset(pParse->azVar, 0, pParse->nzVar*sizeof(pParse->azVar[0]));
+  }
+  if( p->aMem ){
+    p->aMem--;                      /* aMem[] goes from 1..nMem */
+    p->nMem = nMem;                 /*       not from 0..nMem-1 */
+    for(n=1; n<=nMem; n++){
+      p->aMem[n].flags = MEM_Invalid;
+      p->aMem[n].db = db;
+    }
+  }
+  p->explain = pParse->explain;
+  sqlite3VdbeRewind(p);
 }
 
 /*
@@ -45934,6 +59698,7 @@ SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){
   if( pCx==0 ){
     return;
   }
+  sqlite3VdbeSorterClose(p->db, pCx);
   if( pCx->pBt ){
     sqlite3BtreeClose(pCx->pBt);
     /* The pCx->pCursor will be close automatically, if it exists, by
@@ -45946,31 +59711,67 @@ SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){
     sqlite3_vtab_cursor *pVtabCursor = pCx->pVtabCursor;
     const sqlite3_module *pModule = pCx->pModule;
     p->inVtabMethod = 1;
-    (void)sqlite3SafetyOff(p->db);
     pModule->xClose(pVtabCursor);
-    (void)sqlite3SafetyOn(p->db);
     p->inVtabMethod = 0;
   }
 #endif
-  if( !pCx->ephemPseudoTable ){
-    sqlite3DbFree(p->db, pCx->pData);
-  }
 }
 
 /*
-** Close all cursors except for VTab cursors that are currently
-** in use.
+** Copy the values stored in the VdbeFrame structure to its Vdbe. This
+** is used, for example, when a trigger sub-program is halted to restore
+** control to the main program.
 */
-static void closeAllCursorsExceptActiveVtabs(Vdbe *p){
-  int i;
-  if( p->apCsr==0 ) return;
-  for(i=0; i<p->nCursor; i++){
-    VdbeCursor *pC = p->apCsr[i];
-    if( pC && (!p->inVtabMethod || !pC->pVtabCursor) ){
-      sqlite3VdbeFreeCursor(p, pC);
-      p->apCsr[i] = 0;
+SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *pFrame){
+  Vdbe *v = pFrame->v;
+  v->aOnceFlag = pFrame->aOnceFlag;
+  v->nOnceFlag = pFrame->nOnceFlag;
+  v->aOp = pFrame->aOp;
+  v->nOp = pFrame->nOp;
+  v->aMem = pFrame->aMem;
+  v->nMem = pFrame->nMem;
+  v->apCsr = pFrame->apCsr;
+  v->nCursor = pFrame->nCursor;
+  v->db->lastRowid = pFrame->lastRowid;
+  v->nChange = pFrame->nChange;
+  return pFrame->pc;
+}
+
+/*
+** Close all cursors.
+**
+** Also release any dynamic memory held by the VM in the Vdbe.aMem memory 
+** cell array. This is necessary as the memory cell array may contain
+** pointers to VdbeFrame objects, which may in turn contain pointers to
+** open cursors.
+*/
+static void closeAllCursors(Vdbe *p){
+  if( p->pFrame ){
+    VdbeFrame *pFrame;
+    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+    sqlite3VdbeFrameRestore(pFrame);
+  }
+  p->pFrame = 0;
+  p->nFrame = 0;
+
+  if( p->apCsr ){
+    int i;
+    for(i=0; i<p->nCursor; i++){
+      VdbeCursor *pC = p->apCsr[i];
+      if( pC ){
+        sqlite3VdbeFreeCursor(p, pC);
+        p->apCsr[i] = 0;
+      }
     }
   }
+  if( p->aMem ){
+    releaseMemArray(&p->aMem[1], p->nMem);
+  }
+  while( p->pDelFrame ){
+    VdbeFrame *pDel = p->pDelFrame;
+    p->pDelFrame = pDel->pParent;
+    sqlite3VdbeFrameDelete(pDel);
+  }
 }
 
 /*
@@ -45981,23 +59782,18 @@ static void closeAllCursorsExceptActiveVtabs(Vdbe *p){
 ** variables in the aVar[] array.
 */
 static void Cleanup(Vdbe *p){
-  int i;
   sqlite3 *db = p->db;
-  Mem *pMem;
-  closeAllCursorsExceptActiveVtabs(p);
-  for(pMem=&p->aMem[1], i=1; i<=p->nMem; i++, pMem++){
-    if( pMem->flags & MEM_RowSet ){
-      sqlite3RowSetClear(pMem->u.pRowSet);
-    }
-    MemSetTypeFlag(pMem, MEM_Null);
+
+#ifdef SQLITE_DEBUG
+  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and 
+  ** Vdbe.aMem[] arrays have already been cleaned up.  */
+  int i;
+  if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
+  if( p->aMem ){
+    for(i=1; i<=p->nMem; i++) assert( p->aMem[i].flags==MEM_Invalid );
   }
-  releaseMemArray(&p->aMem[1], p->nMem);
-  if( p->contextStack ){
-    sqlite3DbFree(db, p->contextStack);
-  }
-  p->contextStack = 0;
-  p->contextStackDepth = 0;
-  p->contextStackTop = 0;
+#endif
+
   sqlite3DbFree(db, p->zErrMsg);
   p->zErrMsg = 0;
   p->pResultSet = 0;
@@ -46017,7 +59813,7 @@ SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
   releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
   sqlite3DbFree(db, p->aColName);
   n = nResColumn*COLNAME_N;
-  p->nResColumn = nResColumn;
+  p->nResColumn = (u16)nResColumn;
   p->aColName = pColName = (Mem*)sqlite3DbMallocZero(db, sizeof(Mem)*n );
   if( p->aColName==0 ) return;
   while( n-- > 0 ){
@@ -46071,6 +59867,13 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
   int rc = SQLITE_OK;
   int needXcommit = 0;
 
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  /* With this option, sqlite3VtabSync() is defined to be simply 
+  ** SQLITE_OK so p is not used. 
+  */
+  UNUSED_PARAMETER(p);
+#endif
+
   /* Before doing anything else, call the xSync() callback for any
   ** virtual module tables written in this transaction. This has to
   ** be done before determining whether a master journal file is 
@@ -46078,9 +59881,6 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
   ** to the transaction.
   */
   rc = sqlite3VtabSync(db, &p->zErrMsg);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
 
   /* This loop determines (a) if the commit hook should be invoked and
   ** (b) how many database files have open write transactions, not 
@@ -46088,22 +59888,21 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
   ** one database file has an open write transaction, a master journal
   ** file is required for an atomic commit.
   */ 
-  for(i=0; i<db->nDb; i++){ 
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
     Btree *pBt = db->aDb[i].pBt;
     if( sqlite3BtreeIsInTrans(pBt) ){
       needXcommit = 1;
       if( i!=1 ) nTrans++;
+      rc = sqlite3PagerExclusiveLock(sqlite3BtreePager(pBt));
     }
   }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
 
   /* If there are any write-transactions at all, invoke the commit hook */
   if( needXcommit && db->xCommitCallback ){
-    assert( (db->flags & SQLITE_CommitBusy)==0 );
-    db->flags |= SQLITE_CommitBusy;
-    (void)sqlite3SafetyOff(db);
     rc = db->xCommitCallback(db->pCommitArg);
-    (void)sqlite3SafetyOn(db);
-    db->flags &= ~SQLITE_CommitBusy;
     if( rc ){
       return SQLITE_CONSTRAINT;
     }
@@ -46121,7 +59920,7 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
   if( 0==sqlite3Strlen30(sqlite3BtreeGetFilename(db->aDb[0].pBt))
    || nTrans<=1
   ){
-    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
       Btree *pBt = db->aDb[i].pBt;
       if( pBt ){
         rc = sqlite3BtreeCommitPhaseOne(pBt, 0);
@@ -46136,7 +59935,7 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
     for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
       Btree *pBt = db->aDb[i].pBt;
       if( pBt ){
-        rc = sqlite3BtreeCommitPhaseTwo(pBt);
+        rc = sqlite3BtreeCommitPhaseTwo(pBt, 0);
       }
     }
     if( rc==SQLITE_OK ){
@@ -46157,16 +59956,32 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
     sqlite3_file *pMaster = 0;
     i64 offset = 0;
     int res;
+    int retryCount = 0;
+    int nMainFile;
 
     /* Select a master journal file name */
+    nMainFile = sqlite3Strlen30(zMainFile);
+    zMaster = sqlite3MPrintf(db, "%s-mjXXXXXX9XXz", zMainFile);
+    if( zMaster==0 ) return SQLITE_NOMEM;
     do {
       u32 iRandom;
-      sqlite3DbFree(db, zMaster);
-      sqlite3_randomness(sizeof(iRandom), &iRandom);
-      zMaster = sqlite3MPrintf(db, "%s-mj%08X", zMainFile, iRandom&0x7fffffff);
-      if( !zMaster ){
-        return SQLITE_NOMEM;
+      if( retryCount ){
+        if( retryCount>100 ){
+          sqlite3_log(SQLITE_FULL, "MJ delete: %s", zMaster);
+          sqlite3OsDelete(pVfs, zMaster, 0);
+          break;
+        }else if( retryCount==1 ){
+          sqlite3_log(SQLITE_FULL, "MJ collide: %s", zMaster);
+        }
       }
+      retryCount++;
+      sqlite3_randomness(sizeof(iRandom), &iRandom);
+      sqlite3_snprintf(13, &zMaster[nMainFile], "-mj%06X9%02X",
+                               (iRandom>>8)&0xffffff, iRandom&0xff);
+      /* The antipenultimate character of the master journal name must
+      ** be "9" to avoid name collisions when using 8+3 filenames. */
+      assert( zMaster[sqlite3Strlen30(zMaster)-3]=='9' );
+      sqlite3FileSuffix3(zMainFile, zMaster);
       rc = sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS, &res);
     }while( rc==SQLITE_OK && res );
     if( rc==SQLITE_OK ){
@@ -46189,10 +60004,12 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
     */
     for(i=0; i<db->nDb; i++){
       Btree *pBt = db->aDb[i].pBt;
-      if( i==1 ) continue;   /* Ignore the TEMP database */
       if( sqlite3BtreeIsInTrans(pBt) ){
         char const *zFile = sqlite3BtreeGetJournalname(pBt);
-        if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
+        if( zFile==0 ){
+          continue;  /* Ignore TEMP and :memory: databases */
+        }
+        assert( zFile[0]!=0 );
         if( !needSync && !sqlite3BtreeSyncDisabled(pBt) ){
           needSync = 1;
         }
@@ -46210,10 +60027,10 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
     /* Sync the master journal file. If the IOCAP_SEQUENTIAL device
     ** flag is set this is not required.
     */
-    zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
-    if( (needSync 
-     && (0==(sqlite3OsDeviceCharacteristics(pMaster)&SQLITE_IOCAP_SEQUENTIAL))
-     && (rc=sqlite3OsSync(pMaster, SQLITE_SYNC_NORMAL))!=SQLITE_OK) ){
+    if( needSync 
+     && 0==(sqlite3OsDeviceCharacteristics(pMaster)&SQLITE_IOCAP_SEQUENTIAL)
+     && SQLITE_OK!=(rc = sqlite3OsSync(pMaster, SQLITE_SYNC_NORMAL))
+    ){
       sqlite3OsCloseFree(pMaster);
       sqlite3OsDelete(pVfs, zMaster, 0);
       sqlite3DbFree(db, zMaster);
@@ -46228,7 +60045,7 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
     ** sqlite3BtreeCommitPhaseOne(), then there is a chance that the
     ** master journal file will be orphaned. But we cannot delete it,
     ** in case the master journal file name was written into the journal
-    ** file before the failure occured.
+    ** file before the failure occurred.
     */
     for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
       Btree *pBt = db->aDb[i].pBt;
@@ -46237,6 +60054,7 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
       }
     }
     sqlite3OsCloseFree(pMaster);
+    assert( rc!=SQLITE_BUSY );
     if( rc!=SQLITE_OK ){
       sqlite3DbFree(db, zMaster);
       return rc;
@@ -46265,7 +60083,7 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
     for(i=0; i<db->nDb; i++){ 
       Btree *pBt = db->aDb[i].pBt;
       if( pBt ){
-        sqlite3BtreeCommitPhaseTwo(pBt);
+        sqlite3BtreeCommitPhaseTwo(pBt, 1);
       }
     }
     sqlite3EndBenignMalloc();
@@ -46308,31 +60126,92 @@ static void checkActiveVdbeCnt(sqlite3 *db){
 #endif
 
 /*
-** For every Btree that in database connection db which 
-** has been modified, "trip" or invalidate each cursor in
-** that Btree might have been modified so that the cursor
-** can never be used again.  This happens when a rollback
-*** occurs.  We have to trip all the other cursors, even
-** cursor from other VMs in different database connections,
-** so that none of them try to use the data at which they
-** were pointing and which now may have been changed due
-** to the rollback.
+** If the Vdbe passed as the first argument opened a statement-transaction,
+** close it now. Argument eOp must be either SAVEPOINT_ROLLBACK or
+** SAVEPOINT_RELEASE. If it is SAVEPOINT_ROLLBACK, then the statement
+** transaction is rolled back. If eOp is SAVEPOINT_RELEASE, then the 
+** statement transaction is commtted.
 **
-** Remember that a rollback can delete tables complete and
-** reorder rootpages.  So it is not sufficient just to save
-** the state of the cursor.  We have to invalidate the cursor
-** so that it is never used again.
+** If an IO error occurs, an SQLITE_IOERR_XXX error code is returned. 
+** Otherwise SQLITE_OK.
 */
-static void invalidateCursorsOnModifiedBtrees(sqlite3 *db){
-  int i;
-  for(i=0; i<db->nDb; i++){
-    Btree *p = db->aDb[i].pBt;
-    if( p && sqlite3BtreeIsInTrans(p) ){
-      sqlite3BtreeTripAllCursors(p, SQLITE_ABORT);
+SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *p, int eOp){
+  sqlite3 *const db = p->db;
+  int rc = SQLITE_OK;
+
+  /* If p->iStatement is greater than zero, then this Vdbe opened a 
+  ** statement transaction that should be closed here. The only exception
+  ** is that an IO error may have occured, causing an emergency rollback.
+  ** In this case (db->nStatement==0), and there is nothing to do.
+  */
+  if( db->nStatement && p->iStatement ){
+    int i;
+    const int iSavepoint = p->iStatement-1;
+
+    assert( eOp==SAVEPOINT_ROLLBACK || eOp==SAVEPOINT_RELEASE);
+    assert( db->nStatement>0 );
+    assert( p->iStatement==(db->nStatement+db->nSavepoint) );
+
+    for(i=0; i<db->nDb; i++){ 
+      int rc2 = SQLITE_OK;
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        if( eOp==SAVEPOINT_ROLLBACK ){
+          rc2 = sqlite3BtreeSavepoint(pBt, SAVEPOINT_ROLLBACK, iSavepoint);
+        }
+        if( rc2==SQLITE_OK ){
+          rc2 = sqlite3BtreeSavepoint(pBt, SAVEPOINT_RELEASE, iSavepoint);
+        }
+        if( rc==SQLITE_OK ){
+          rc = rc2;
+        }
+      }
+    }
+    db->nStatement--;
+    p->iStatement = 0;
+
+    if( rc==SQLITE_OK ){
+      if( eOp==SAVEPOINT_ROLLBACK ){
+        rc = sqlite3VtabSavepoint(db, SAVEPOINT_ROLLBACK, iSavepoint);
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3VtabSavepoint(db, SAVEPOINT_RELEASE, iSavepoint);
+      }
+    }
+
+    /* If the statement transaction is being rolled back, also restore the 
+    ** database handles deferred constraint counter to the value it had when 
+    ** the statement transaction was opened.  */
+    if( eOp==SAVEPOINT_ROLLBACK ){
+      db->nDeferredCons = p->nStmtDefCons;
     }
   }
+  return rc;
 }
 
+/*
+** This function is called when a transaction opened by the database 
+** handle associated with the VM passed as an argument is about to be 
+** committed. If there are outstanding deferred foreign key constraint
+** violations, return SQLITE_ERROR. Otherwise, SQLITE_OK.
+**
+** If there are outstanding FK violations and this function returns 
+** SQLITE_ERROR, set the result of the VM to SQLITE_CONSTRAINT and write
+** an error message to it. Then return SQLITE_ERROR.
+*/
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE int sqlite3VdbeCheckFk(Vdbe *p, int deferred){
+  sqlite3 *db = p->db;
+  if( (deferred && db->nDeferredCons>0) || (!deferred && p->nFkConstraint>0) ){
+    p->rc = SQLITE_CONSTRAINT;
+    p->errorAction = OE_Abort;
+    sqlite3SetString(&p->zErrMsg, db, "foreign key constraint failed");
+    return SQLITE_ERROR;
+  }
+  return SQLITE_OK;
+}
+#endif
+
 /*
 ** This routine is called the when a VDBE tries to halt.  If the VDBE
 ** has made changes and is in autocommit mode, then commit those
@@ -46347,10 +60226,8 @@ static void invalidateCursorsOnModifiedBtrees(sqlite3 *db){
 ** means the close did not happen and needs to be repeated.
 */
 SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
+  int rc;                         /* Used to store transient return codes */
   sqlite3 *db = p->db;
-  int i;
-  int (*xFunc)(Btree *pBt) = 0;  /* Function to call on each btree backend */
-  int isSpecialError;            /* Set to true if SQLITE_NOMEM or IOERR */
 
   /* This function contains the logic that determines if a statement or
   ** transaction will be committed or rolled back as a result of the
@@ -46371,7 +60248,8 @@ SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
   if( p->db->mallocFailed ){
     p->rc = SQLITE_NOMEM;
   }
-  closeAllCursorsExceptActiveVtabs(p);
+  if( p->aOnceFlag ) memset(p->aOnceFlag, 0, p->nOnceFlag);
+  closeAllCursors(p);
   if( p->magic!=VDBE_MAGIC_RUN ){
     return SQLITE_OK;
   }
@@ -46380,39 +60258,51 @@ SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
   /* No commit or rollback needed if the program never started */
   if( p->pc>=0 ){
     int mrc;   /* Primary error code from p->rc */
+    int eStatementOp = 0;
+    int isSpecialError;            /* Set to true if a 'special' error */
 
     /* Lock all btrees used by the statement */
-    sqlite3BtreeMutexArrayEnter(&p->aMutex);
+    sqlite3VdbeEnter(p);
 
     /* Check for one of the special errors */
     mrc = p->rc & 0xff;
+    assert( p->rc!=SQLITE_IOERR_BLOCKED );  /* This error no longer exists */
     isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
                      || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
     if( isSpecialError ){
-      /* If the query was read-only, we need do no rollback at all. Otherwise,
-      ** proceed with the special handling.
+      /* If the query was read-only and the error code is SQLITE_INTERRUPT, 
+      ** no rollback is necessary. Otherwise, at least a savepoint 
+      ** transaction must be rolled back to restore the database to a 
+      ** consistent state.
+      **
+      ** Even if the statement is read-only, it is important to perform
+      ** a statement or transaction rollback operation. If the error 
+      ** occured while writing to the journal, sub-journal or database
+      ** file as part of an effort to free up cache space (see function
+      ** pagerStress() in pager.c), the rollback is required to restore 
+      ** the pager to a consistent state.
       */
       if( !p->readOnly || mrc!=SQLITE_INTERRUPT ){
-        if( p->rc==SQLITE_IOERR_BLOCKED && p->usesStmtJournal ){
-          xFunc = sqlite3BtreeRollbackStmt;
-          p->rc = SQLITE_BUSY;
-        }else if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL)
-                   && p->usesStmtJournal ){
-          xFunc = sqlite3BtreeRollbackStmt;
+        if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && p->usesStmtJournal ){
+          eStatementOp = SAVEPOINT_ROLLBACK;
         }else{
           /* We are forced to roll back the active transaction. Before doing
           ** so, abort any other statements this handle currently has active.
           */
-          invalidateCursorsOnModifiedBtrees(db);
-          sqlite3RollbackAll(db);
+          sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
           sqlite3CloseSavepoints(db);
           db->autoCommit = 1;
         }
       }
     }
+
+    /* Check for immediate foreign key violations. */
+    if( p->rc==SQLITE_OK ){
+      sqlite3VdbeCheckFk(p, 0);
+    }
   
-    /* If the auto-commit flag is set and this is the only active vdbe, then
-    ** we do either a commit or rollback of the current transaction. 
+    /* If the auto-commit flag is set and this is the only active writer 
+    ** VM, then we do either a commit or rollback of the current transaction. 
     **
     ** Note: This block also runs if one of the special errors handled 
     ** above has occurred. 
@@ -46420,83 +60310,82 @@ SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
     if( !sqlite3VtabInSync(db) 
      && db->autoCommit 
      && db->writeVdbeCnt==(p->readOnly==0) 
-     && (db->flags & SQLITE_CommitBusy)==0
     ){
       if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
-        /* The auto-commit flag is true, and the vdbe program was 
-        ** successful or hit an 'OR FAIL' constraint. This means a commit 
-        ** is required.
-        */
-        int rc = vdbeCommit(db, p);
-        if( rc==SQLITE_BUSY ){
-          sqlite3BtreeMutexArrayLeave(&p->aMutex);
+        rc = sqlite3VdbeCheckFk(p, 1);
+        if( rc!=SQLITE_OK ){
+          if( NEVER(p->readOnly) ){
+            sqlite3VdbeLeave(p);
+            return SQLITE_ERROR;
+          }
+          rc = SQLITE_CONSTRAINT;
+        }else{ 
+          /* The auto-commit flag is true, the vdbe program was successful 
+          ** or hit an 'OR FAIL' constraint and there are no deferred foreign
+          ** key constraints to hold up the transaction. This means a commit 
+          ** is required. */
+          rc = vdbeCommit(db, p);
+        }
+        if( rc==SQLITE_BUSY && p->readOnly ){
+          sqlite3VdbeLeave(p);
           return SQLITE_BUSY;
         }else if( rc!=SQLITE_OK ){
           p->rc = rc;
-          sqlite3RollbackAll(db);
+          sqlite3RollbackAll(db, SQLITE_OK);
         }else{
+          db->nDeferredCons = 0;
           sqlite3CommitInternalChanges(db);
         }
       }else{
-        sqlite3RollbackAll(db);
+        sqlite3RollbackAll(db, SQLITE_OK);
       }
-    }else if( !xFunc ){
+      db->nStatement = 0;
+    }else if( eStatementOp==0 ){
       if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
-        if( p->openedStatement ){
-          xFunc = sqlite3BtreeCommitStmt;
-        } 
+        eStatementOp = SAVEPOINT_RELEASE;
       }else if( p->errorAction==OE_Abort ){
-        xFunc = sqlite3BtreeRollbackStmt;
+        eStatementOp = SAVEPOINT_ROLLBACK;
       }else{
-        invalidateCursorsOnModifiedBtrees(db);
-        sqlite3RollbackAll(db);
+        sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
         sqlite3CloseSavepoints(db);
         db->autoCommit = 1;
       }
     }
   
-    /* If xFunc is not NULL, then it is one of sqlite3BtreeRollbackStmt or
-    ** sqlite3BtreeCommitStmt. Call it once on each backend. If an error occurs
-    ** and the return code is still SQLITE_OK, set the return code to the new
-    ** error value.
+    /* If eStatementOp is non-zero, then a statement transaction needs to
+    ** be committed or rolled back. Call sqlite3VdbeCloseStatement() to
+    ** do so. If this operation returns an error, and the current statement
+    ** error code is SQLITE_OK or SQLITE_CONSTRAINT, then promote the
+    ** current statement error code.
     */
-    assert(!xFunc ||
-      xFunc==sqlite3BtreeCommitStmt ||
-      xFunc==sqlite3BtreeRollbackStmt
-    );
-    for(i=0; xFunc && i<db->nDb; i++){ 
-      int rc;
-      Btree *pBt = db->aDb[i].pBt;
-      if( pBt ){
-        rc = xFunc(pBt);
-        if( rc && (p->rc==SQLITE_OK || p->rc==SQLITE_CONSTRAINT) ){
+    if( eStatementOp ){
+      rc = sqlite3VdbeCloseStatement(p, eStatementOp);
+      if( rc ){
+        if( p->rc==SQLITE_OK || p->rc==SQLITE_CONSTRAINT ){
           p->rc = rc;
           sqlite3DbFree(db, p->zErrMsg);
           p->zErrMsg = 0;
         }
+        sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+        sqlite3CloseSavepoints(db);
+        db->autoCommit = 1;
       }
     }
   
-    /* If this was an INSERT, UPDATE or DELETE and the statement was committed, 
-    ** set the change counter. 
+    /* If this was an INSERT, UPDATE or DELETE and no statement transaction
+    ** has been rolled back, update the database connection change-counter. 
     */
-    if( p->changeCntOn && p->pc>=0 ){
-      if( !xFunc || xFunc==sqlite3BtreeCommitStmt ){
+    if( p->changeCntOn ){
+      if( eStatementOp!=SAVEPOINT_ROLLBACK ){
         sqlite3VdbeSetChanges(db, p->nChange);
       }else{
         sqlite3VdbeSetChanges(db, 0);
       }
       p->nChange = 0;
     }
-  
-    /* Rollback or commit any schema changes that occurred. */
-    if( p->rc!=SQLITE_OK && db->flags&SQLITE_InternChanges ){
-      sqlite3ResetInternalSchema(db, 0);
-      db->flags = (db->flags | SQLITE_InternChanges);
-    }
 
     /* Release the locks */
-    sqlite3BtreeMutexArrayLeave(&p->aMutex);
+    sqlite3VdbeLeave(p);
   }
 
   /* We have successfully halted and closed the VM.  Record this fact. */
@@ -46513,7 +60402,16 @@ SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
     p->rc = SQLITE_NOMEM;
   }
 
-  return SQLITE_OK;
+  /* If the auto-commit flag is set to true, then any locks that were held
+  ** by connection db have now been released. Call sqlite3ConnectionUnlocked() 
+  ** to invoke any required unlock-notify callbacks.
+  */
+  if( db->autoCommit ){
+    sqlite3ConnectionUnlocked(db);
+  }
+
+  assert( db->activeVdbeCnt>0 || db->autoCommit==0 || db->nStatement==0 );
+  return (p->rc==SQLITE_BUSY ? SQLITE_BUSY : SQLITE_OK);
 }
 
 
@@ -46525,6 +60423,30 @@ SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe *p){
   p->rc = SQLITE_OK;
 }
 
+/*
+** Copy the error code and error message belonging to the VDBE passed
+** as the first argument to its database handle (so that they will be 
+** returned by calls to sqlite3_errcode() and sqlite3_errmsg()).
+**
+** This function does not clear the VDBE error code or message, just
+** copies them to the database handle.
+*/
+SQLITE_PRIVATE int sqlite3VdbeTransferError(Vdbe *p){
+  sqlite3 *db = p->db;
+  int rc = p->rc;
+  if( p->zErrMsg ){
+    u8 mallocFailed = db->mallocFailed;
+    sqlite3BeginBenignMalloc();
+    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, SQLITE_TRANSIENT);
+    sqlite3EndBenignMalloc();
+    db->mallocFailed = mallocFailed;
+    db->errCode = rc;
+  }else{
+    sqlite3Error(db, rc, 0);
+  }
+  return rc;
+}
+
 /*
 ** Clean up a VDBE after execution but do not delete the VDBE just yet.
 ** Write any error messages into *pzErrMsg.  Return the result code.
@@ -46544,9 +60466,7 @@ SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe *p){
   ** error, then it might not have been halted properly.  So halt
   ** it now.
   */
-  (void)sqlite3SafetyOn(db);
   sqlite3VdbeHalt(p);
-  (void)sqlite3SafetyOff(db);
 
   /* If the VDBE has be run even partially, then transfer the error code
   ** and error message from the VDBE into the main database structure.  But
@@ -46554,18 +60474,10 @@ SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe *p){
   ** instructions yet, leave the main database error information unchanged.
   */
   if( p->pc>=0 ){
-    if( p->zErrMsg ){
-      sqlite3BeginBenignMalloc();
-      sqlite3ValueSetStr(db->pErr,-1,p->zErrMsg,SQLITE_UTF8,SQLITE_TRANSIENT);
-      sqlite3EndBenignMalloc();
-      db->errCode = p->rc;
-      sqlite3DbFree(db, p->zErrMsg);
-      p->zErrMsg = 0;
-    }else if( p->rc ){
-      sqlite3Error(db, p->rc, 0);
-    }else{
-      sqlite3Error(db, SQLITE_OK, 0);
-    }
+    sqlite3VdbeTransferError(p);
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = 0;
+    if( p->runOnlyOnce ) p->expired = 1;
   }else if( p->rc && p->expired ){
     /* The expired flag was set on the VDBE before the first call
     ** to sqlite3_step(). For consistency (since sqlite3_step() was
@@ -46618,8 +60530,6 @@ SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe *p){
   if( p->magic==VDBE_MAGIC_RUN || p->magic==VDBE_MAGIC_HALT ){
     rc = sqlite3VdbeReset(p);
     assert( (rc & p->db->errMask)==rc );
-  }else if( p->magic!=VDBE_MAGIC_INIT ){
-    return SQLITE_MISUSE;
   }
   sqlite3VdbeDelete(p);
   return rc;
@@ -46635,7 +60545,7 @@ SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(VdbeFunc *pVdbeFunc, int mask){
   int i;
   for(i=0; i<pVdbeFunc->nAux; i++){
     struct AuxData *pAux = &pVdbeFunc->apAux[i];
-    if( (i>31 || !(mask&(1<<i))) && pAux->pAux ){
+    if( (i>31 || !(mask&(((u32)1)<<i))) && pAux->pAux ){
       if( pAux->xDelete ){
         pAux->xDelete(pAux->pAux);
       }
@@ -46644,15 +60554,45 @@ SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(VdbeFunc *pVdbeFunc, int mask){
   }
 }
 
+/*
+** Free all memory associated with the Vdbe passed as the second argument.
+** The difference between this function and sqlite3VdbeDelete() is that
+** VdbeDelete() also unlinks the Vdbe from the list of VMs associated with
+** the database connection.
+*/
+SQLITE_PRIVATE void sqlite3VdbeDeleteObject(sqlite3 *db, Vdbe *p){
+  SubProgram *pSub, *pNext;
+  int i;
+  assert( p->db==0 || p->db==db );
+  releaseMemArray(p->aVar, p->nVar);
+  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
+  for(pSub=p->pProgram; pSub; pSub=pNext){
+    pNext = pSub->pNext;
+    vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
+    sqlite3DbFree(db, pSub);
+  }
+  for(i=p->nzVar-1; i>=0; i--) sqlite3DbFree(db, p->azVar[i]);
+  vdbeFreeOpArray(db, p->aOp, p->nOp);
+  sqlite3DbFree(db, p->aLabel);
+  sqlite3DbFree(db, p->aColName);
+  sqlite3DbFree(db, p->zSql);
+  sqlite3DbFree(db, p->pFree);
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
+  sqlite3DbFree(db, p->zExplain);
+  sqlite3DbFree(db, p->pExplain);
+#endif
+  sqlite3DbFree(db, p);
+}
+
 /*
 ** Delete an entire VDBE.
 */
 SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe *p){
-  int i;
   sqlite3 *db;
 
-  if( p==0 ) return;
+  if( NEVER(p==0) ) return;
   db = p->db;
+  assert( sqlite3_mutex_held(db->mutex) );
   if( p->pPrev ){
     p->pPrev->pNext = p->pNext;
   }else{
@@ -46662,32 +60602,23 @@ SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe *p){
   if( p->pNext ){
     p->pNext->pPrev = p->pPrev;
   }
-  if( p->aOp ){
-    Op *pOp = p->aOp;
-    for(i=0; i<p->nOp; i++, pOp++){
-      freeP4(db, pOp->p4type, pOp->p4.p);
-#ifdef SQLITE_DEBUG
-      sqlite3DbFree(db, pOp->zComment);
-#endif     
-    }
-    sqlite3DbFree(db, p->aOp);
-  }
-  releaseMemArray(p->aVar, p->nVar);
-  sqlite3DbFree(db, p->aLabel);
-  if( p->aMem ){
-    sqlite3DbFree(db, &p->aMem[1]);
-  }
-  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
-  sqlite3DbFree(db, p->aColName);
-  sqlite3DbFree(db, p->zSql);
   p->magic = VDBE_MAGIC_DEAD;
-  sqlite3DbFree(db, p);
+  p->db = 0;
+  sqlite3VdbeDeleteObject(db, p);
 }
 
 /*
+** Make sure the cursor p is ready to read or write the row to which it
+** was last positioned.  Return an error code if an OOM fault or I/O error
+** prevents us from positioning the cursor to its correct position.
+**
 ** If a MoveTo operation is pending on the given cursor, then do that
-** MoveTo now.  Return an error code.  If no MoveTo is pending, this
-** routine does nothing and returns SQLITE_OK.
+** MoveTo now.  If no move is pending, check to see if the row has been
+** deleted out from under the cursor and if it has, mark the row as
+** a NULL row.
+**
+** If the cursor is already pointing to the correct row and that row has
+** not been deleted out from under the cursor, then this routine is a no-op.
 */
 SQLITE_PRIVATE int sqlite3VdbeCursorMoveto(VdbeCursor *p){
   if( p->deferredMoveto ){
@@ -46698,18 +60629,15 @@ SQLITE_PRIVATE int sqlite3VdbeCursorMoveto(VdbeCursor *p){
     assert( p->isTable );
     rc = sqlite3BtreeMovetoUnpacked(p->pCursor, 0, p->movetoTarget, 0, &res);
     if( rc ) return rc;
-    p->lastRowid = keyToInt(p->movetoTarget);
-    p->rowidIsValid = res==0 ?1:0;
-    if( res<0 ){
-      rc = sqlite3BtreeNext(p->pCursor, &res);
-      if( rc ) return rc;
-    }
+    p->lastRowid = p->movetoTarget;
+    if( res!=0 ) return SQLITE_CORRUPT_BKPT;
+    p->rowidIsValid = 1;
 #ifdef SQLITE_TEST
     sqlite3_search_count++;
 #endif
     p->deferredMoveto = 0;
     p->cacheStatus = CACHE_STALE;
-  }else if( p->pCursor ){
+  }else if( ALWAYS(p->pCursor) ){
     int hasMoved;
     int rc = sqlite3BtreeCursorHasMoved(p->pCursor, &hasMoved);
     if( rc ) return rc;
@@ -46781,7 +60709,13 @@ SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem *pMem, int file_format){
     if( file_format>=4 && (i&1)==i ){
       return 8+(u32)i;
     }
-    u = i<0 ? -i : i;
+    if( i<0 ){
+      if( i<(-MAX_6BYTE) ) return 6;
+      /* Previous test prevents:  u = -(-9223372036854775808) */
+      u = -i;
+    }else{
+      u = i;
+    }
     if( u<=127 ) return 1;
     if( u<=32767 ) return 2;
     if( u<=8388607 ) return 3;
@@ -46804,7 +60738,7 @@ SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem *pMem, int file_format){
 /*
 ** Return the length of the data corresponding to the supplied serial-type.
 */
-SQLITE_PRIVATE int sqlite3VdbeSerialTypeLen(u32 serial_type){
+SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32 serial_type){
   if( serial_type>=12 ){
     return (serial_type-12)/2;
   }else{
@@ -46884,14 +60818,14 @@ static u64 floatSwap(u64 in){
 ** of bytes in the zero-filled tail is included in the return value only
 ** if those bytes were zeroed in buf[].
 */ 
-SQLITE_PRIVATE int sqlite3VdbeSerialPut(u8 *buf, int nBuf, Mem *pMem, int file_format){
+SQLITE_PRIVATE u32 sqlite3VdbeSerialPut(u8 *buf, int nBuf, Mem *pMem, int file_format){
   u32 serial_type = sqlite3VdbeSerialType(pMem, file_format);
-  int len;
+  u32 len;
 
   /* Integer and Real */
   if( serial_type<=7 && serial_type>0 ){
     u64 v;
-    int i;
+    u32 i;
     if( serial_type==7 ){
       assert( sizeof(v)==sizeof(pMem->r) );
       memcpy(&v, &pMem->r, sizeof(v));
@@ -46900,7 +60834,7 @@ SQLITE_PRIVATE int sqlite3VdbeSerialPut(u8 *buf, int nBuf, Mem *pMem, int file_f
       v = pMem->u.i;
     }
     len = i = sqlite3VdbeSerialTypeLen(serial_type);
-    assert( len<=nBuf );
+    assert( len<=(u32)nBuf );
     while( i-- ){
       buf[i] = (u8)(v&0xFF);
       v >>= 8;
@@ -46911,14 +60845,15 @@ SQLITE_PRIVATE int sqlite3VdbeSerialPut(u8 *buf, int nBuf, Mem *pMem, int file_f
   /* String or blob */
   if( serial_type>=12 ){
     assert( pMem->n + ((pMem->flags & MEM_Zero)?pMem->u.nZero:0)
-             == sqlite3VdbeSerialTypeLen(serial_type) );
+             == (int)sqlite3VdbeSerialTypeLen(serial_type) );
     assert( pMem->n<=nBuf );
     len = pMem->n;
     memcpy(buf, pMem->z, len);
     if( pMem->flags & MEM_Zero ){
       len += pMem->u.nZero;
-      if( len>nBuf ){
-        len = nBuf;
+      assert( nBuf>=0 );
+      if( len > (u32)nBuf ){
+        len = (u32)nBuf;
       }
       memset(&buf[pMem->n], 0, len-pMem->n);
     }
@@ -46933,7 +60868,7 @@ SQLITE_PRIVATE int sqlite3VdbeSerialPut(u8 *buf, int nBuf, Mem *pMem, int file_f
 ** Deserialize the data blob pointed to by buf as serial type serial_type
 ** and store the result in pMem.  Return the number of bytes read.
 */ 
-SQLITE_PRIVATE int sqlite3VdbeSerialGet(
+SQLITE_PRIVATE u32 sqlite3VdbeSerialGet(
   const unsigned char *buf,     /* Buffer to deserialize from */
   u32 serial_type,              /* Serial type to deserialize */
   Mem *pMem                     /* Memory cell to write value into */
@@ -47011,7 +60946,7 @@ SQLITE_PRIVATE int sqlite3VdbeSerialGet(
       return 0;
     }
     default: {
-      int len = (serial_type-12)/2;
+      u32 len = (serial_type-12)/2;
       pMem->z = (char *)buf;
       pMem->n = len;
       pMem->xDel = 0;
@@ -47026,59 +60961,81 @@ SQLITE_PRIVATE int sqlite3VdbeSerialGet(
   return 0;
 }
 
+/*
+** This routine is used to allocate sufficient space for an UnpackedRecord
+** structure large enough to be used with sqlite3VdbeRecordUnpack() if
+** the first argument is a pointer to KeyInfo structure pKeyInfo.
+**
+** The space is either allocated using sqlite3DbMallocRaw() or from within
+** the unaligned buffer passed via the second and third arguments (presumably
+** stack space). If the former, then *ppFree is set to a pointer that should
+** be eventually freed by the caller using sqlite3DbFree(). Or, if the 
+** allocation comes from the pSpace/szSpace buffer, *ppFree is set to NULL
+** before returning.
+**
+** If an OOM error occurs, NULL is returned.
+*/
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(
+  KeyInfo *pKeyInfo,              /* Description of the record */
+  char *pSpace,                   /* Unaligned space available */
+  int szSpace,                    /* Size of pSpace[] in bytes */
+  char **ppFree                   /* OUT: Caller should free this pointer */
+){
+  UnpackedRecord *p;              /* Unpacked record to return */
+  int nOff;                       /* Increment pSpace by nOff to align it */
+  int nByte;                      /* Number of bytes required for *p */
+
+  /* We want to shift the pointer pSpace up such that it is 8-byte aligned.
+  ** Thus, we need to calculate a value, nOff, between 0 and 7, to shift 
+  ** it by.  If pSpace is already 8-byte aligned, nOff should be zero.
+  */
+  nOff = (8 - (SQLITE_PTR_TO_INT(pSpace) & 7)) & 7;
+  nByte = ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nField+1);
+  if( nByte>szSpace+nOff ){
+    p = (UnpackedRecord *)sqlite3DbMallocRaw(pKeyInfo->db, nByte);
+    *ppFree = (char *)p;
+    if( !p ) return 0;
+  }else{
+    p = (UnpackedRecord*)&pSpace[nOff];
+    *ppFree = 0;
+  }
+
+  p->aMem = (Mem*)&((char*)p)[ROUND8(sizeof(UnpackedRecord))];
+  p->pKeyInfo = pKeyInfo;
+  p->nField = pKeyInfo->nField + 1;
+  return p;
+}
 
 /*
-** Given the nKey-byte encoding of a record in pKey[], parse the
-** record into a UnpackedRecord structure.  Return a pointer to
-** that structure.
-**
-** The calling function might provide szSpace bytes of memory
-** space at pSpace.  This space can be used to hold the returned
-** VDbeParsedRecord structure if it is large enough.  If it is
-** not big enough, space is obtained from sqlite3_malloc().
-**
-** The returned structure should be closed by a call to
-** sqlite3VdbeDeleteUnpackedRecord().
+** Given the nKey-byte encoding of a record in pKey[], populate the 
+** UnpackedRecord structure indicated by the fourth argument with the
+** contents of the decoded record.
 */ 
-SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeRecordUnpack(
+SQLITE_PRIVATE void sqlite3VdbeRecordUnpack(
   KeyInfo *pKeyInfo,     /* Information about the record format */
   int nKey,              /* Size of the binary record */
   const void *pKey,      /* The binary record */
-  UnpackedRecord *pSpace,/* Space available to hold resulting object */
-  int szSpace            /* Size of pSpace[] in bytes */
+  UnpackedRecord *p      /* Populate this structure before returning. */
 ){
   const unsigned char *aKey = (const unsigned char *)pKey;
-  UnpackedRecord *p;
-  int nByte, d;
-  u32 idx;
-  u16 u;                 /* Unsigned loop counter */
+  int d; 
+  u32 idx;                        /* Offset in aKey[] to read from */
+  u16 u;                          /* Unsigned loop counter */
   u32 szHdr;
-  Mem *pMem;
-  
-  assert( sizeof(Mem)>sizeof(*p) );
-  nByte = sizeof(Mem)*(pKeyInfo->nField+2);
-  if( nByte>szSpace ){
-    p = sqlite3DbMallocRaw(pKeyInfo->db, nByte);
-    if( p==0 ) return 0;
-    p->flags = UNPACKED_NEED_FREE | UNPACKED_NEED_DESTROY;
-  }else{
-    p = pSpace;
-    p->flags = UNPACKED_NEED_DESTROY;
-  }
-  p->pKeyInfo = pKeyInfo;
-  p->nField = pKeyInfo->nField + 1;
-  p->aMem = pMem = &((Mem*)p)[1];
+  Mem *pMem = p->aMem;
+
+  p->flags = 0;
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
   idx = getVarint32(aKey, szHdr);
   d = szHdr;
   u = 0;
-  while( idx<szHdr && u<p->nField ){
+  while( idx<szHdr && u<p->nField && d<=nKey ){
     u32 serial_type;
 
     idx += getVarint32(&aKey[idx], serial_type);
-    if( d>=nKey && sqlite3VdbeSerialTypeLen(serial_type)>0 ) break;
     pMem->enc = pKeyInfo->enc;
     pMem->db = pKeyInfo->db;
-    pMem->flags = 0;
+    /* pMem->flags = 0; // sqlite3VdbeSerialGet() will set this for us */
     pMem->zMalloc = 0;
     d += sqlite3VdbeSerialGet(&aKey[d], serial_type, pMem);
     pMem++;
@@ -47086,27 +61043,6 @@ SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeRecordUnpack(
   }
   assert( u<=pKeyInfo->nField + 1 );
   p->nField = u;
-  return (void*)p;
-}
-
-/*
-** This routine destroys a UnpackedRecord object
-*/
-SQLITE_PRIVATE void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord *p){
-  if( p ){
-    if( p->flags & UNPACKED_NEED_DESTROY ){
-      int i;
-      Mem *pMem;
-      for(i=0, pMem=p->aMem; i<p->nField; i++, pMem++){
-        if( pMem->zMalloc ){
-          sqlite3VdbeMemRelease(pMem);
-        }
-      }
-    }
-    if( p->flags & UNPACKED_NEED_FREE ){
-      sqlite3DbFree(p->pKeyInfo->db, p);
-    }
-  }
 }
 
 /*
@@ -47125,15 +61061,6 @@ SQLITE_PRIVATE void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord *p){
 ** Or if the UNPACKED_MATCH_PREFIX flag is set and the prefixes are
 ** equal, then the keys are considered to be equal and
 ** the parts beyond the common prefix are ignored.
-**
-** If the UNPACKED_IGNORE_ROWID flag is set, then the last byte of
-** the header of pKey1 is ignored.  It is assumed that pKey1 is
-** an index key, and thus ends with a rowid value.  The last byte
-** of the header will therefore be the serial type of the rowid:
-** one of 1, 2, 3, 4, 5, 6, 8, or 9 - the integer serial types.
-** The serial type of the final rowid will always be a single byte.
-** By ignoring this last byte of the header, we force the comparison
-** to ignore the rowid at the end of key1.
 */
 SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
   int nKey1, const void *pKey1, /* Left key */
@@ -47152,14 +61079,20 @@ SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
   pKeyInfo = pPKey2->pKeyInfo;
   mem1.enc = pKeyInfo->enc;
   mem1.db = pKeyInfo->db;
-  mem1.flags = 0;
-  mem1.zMalloc = 0;
+  /* mem1.flags = 0;  // Will be initialized by sqlite3VdbeSerialGet() */
+  VVA_ONLY( mem1.zMalloc = 0; ) /* Only needed by assert() statements */
+
+  /* Compilers may complain that mem1.u.i is potentially uninitialized.
+  ** We could initialize it, as shown here, to silence those complaints.
+  ** But in fact, mem1.u.i will never actually be used uninitialized, and doing 
+  ** the unnecessary initialization has a measurable negative performance
+  ** impact, since this routine is a very high runner.  And so, we choose
+  ** to ignore the compiler warnings and leave this variable uninitialized.
+  */
+  /*  mem1.u.i = 0;  // not needed, here to silence compiler warning */
   
   idx1 = getVarint32(aKey1, szHdr1);
   d1 = szHdr1;
-  if( pPKey2->flags & UNPACKED_IGNORE_ROWID ){
-    szHdr1--;
-  }
   nField = pKeyInfo->nField;
   while( idx1<szHdr1 && i<pPKey2->nField ){
     u32 serial_type1;
@@ -47177,33 +61110,52 @@ SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
     rc = sqlite3MemCompare(&mem1, &pPKey2->aMem[i],
                            i<nField ? pKeyInfo->aColl[i] : 0);
     if( rc!=0 ){
-      break;
+      assert( mem1.zMalloc==0 );  /* See comment below */
+
+      /* Invert the result if we are using DESC sort order. */
+      if( pKeyInfo->aSortOrder && i<nField && pKeyInfo->aSortOrder[i] ){
+        rc = -rc;
+      }
+    
+      /* If the PREFIX_SEARCH flag is set and all fields except the final
+      ** rowid field were equal, then clear the PREFIX_SEARCH flag and set 
+      ** pPKey2->rowid to the value of the rowid field in (pKey1, nKey1).
+      ** This is used by the OP_IsUnique opcode.
+      */
+      if( (pPKey2->flags & UNPACKED_PREFIX_SEARCH) && i==(pPKey2->nField-1) ){
+        assert( idx1==szHdr1 && rc );
+        assert( mem1.flags & MEM_Int );
+        pPKey2->flags &= ~UNPACKED_PREFIX_SEARCH;
+        pPKey2->rowid = mem1.u.i;
+      }
+    
+      return rc;
     }
     i++;
   }
-  if( mem1.zMalloc ) sqlite3VdbeMemRelease(&mem1);
 
-  if( rc==0 ){
-    /* rc==0 here means that one of the keys ran out of fields and
-    ** all the fields up to that point were equal. If the UNPACKED_INCRKEY
-    ** flag is set, then break the tie by treating key2 as larger.
-    ** If the UPACKED_PREFIX_MATCH flag is set, then keys with common prefixes
-    ** are considered to be equal.  Otherwise, the longer key is the 
-    ** larger.  As it happens, the pPKey2 will always be the longer
-    ** if there is a difference.
-    */
-    if( pPKey2->flags & UNPACKED_INCRKEY ){
-      rc = -1;
-    }else if( pPKey2->flags & UNPACKED_PREFIX_MATCH ){
-      /* Leave rc==0 */
-    }else if( idx1<szHdr1 ){
-      rc = 1;
-    }
-  }else if( pKeyInfo->aSortOrder && i<pKeyInfo->nField
-               && pKeyInfo->aSortOrder[i] ){
-    rc = -rc;
+  /* No memory allocation is ever used on mem1.  Prove this using
+  ** the following assert().  If the assert() fails, it indicates a
+  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).
+  */
+  assert( mem1.zMalloc==0 );
+
+  /* rc==0 here means that one of the keys ran out of fields and
+  ** all the fields up to that point were equal. If the UNPACKED_INCRKEY
+  ** flag is set, then break the tie by treating key2 as larger.
+  ** If the UPACKED_PREFIX_MATCH flag is set, then keys with common prefixes
+  ** are considered to be equal.  Otherwise, the longer key is the 
+  ** larger.  As it happens, the pPKey2 will always be the longer
+  ** if there is a difference.
+  */
+  assert( rc==0 );
+  if( pPKey2->flags & UNPACKED_INCRKEY ){
+    rc = -1;
+  }else if( pPKey2->flags & UNPACKED_PREFIX_MATCH ){
+    /* Leave rc==0 */
+  }else if( idx1<szHdr1 ){
+    rc = 1;
   }
-
   return rc;
 }
  
@@ -47216,7 +61168,7 @@ SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
 ** pCur might be pointing to text obtained from a corrupt database file.
 ** So the content cannot be trusted.  Do appropriate checks on the content.
 */
-SQLITE_PRIVATE int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(sqlite3 *db, BtCursor *pCur, i64 *rowid){
   i64 nCellKey = 0;
   int rc;
   u32 szHdr;        /* Size of the header */
@@ -47224,17 +61176,20 @@ SQLITE_PRIVATE int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
   u32 lenRowid;     /* Size of the rowid */
   Mem m, v;
 
+  UNUSED_PARAMETER(db);
+
   /* Get the size of the index entry.  Only indices entries of less
-  ** than 2GiB are support - anything large must be database corruption */
-  sqlite3BtreeKeySize(pCur, &nCellKey);
-  if( unlikely(nCellKey<=0 || nCellKey>0x7fffffff) ){
-    return SQLITE_CORRUPT_BKPT;
-  }
+  ** than 2GiB are support - anything large must be database corruption.
+  ** Any corruption is detected in sqlite3BtreeParseCellPtr(), though, so
+  ** this code can safely assume that nCellKey is 32-bits  
+  */
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  VVA_ONLY(rc =) sqlite3BtreeKeySize(pCur, &nCellKey);
+  assert( rc==SQLITE_OK );     /* pCur is always valid so KeySize cannot fail */
+  assert( (nCellKey & SQLITE_MAX_U32)==(u64)nCellKey );
 
   /* Read in the complete content of the index entry */
-  m.flags = 0;
-  m.db = 0;
-  m.zMalloc = 0;
+  memset(&m, 0, sizeof(m));
   rc = sqlite3VdbeMemFromBtree(pCur, 0, (int)nCellKey, 1, &m);
   if( rc ){
     return rc;
@@ -47242,9 +61197,9 @@ SQLITE_PRIVATE int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
 
   /* The index entry must begin with a header size */
   (void)getVarint32((u8*)m.z, szHdr);
-  testcase( szHdr==2 );
+  testcase( szHdr==3 );
   testcase( szHdr==m.n );
-  if( unlikely(szHdr<2 || (int)szHdr>m.n) ){
+  if( unlikely(szHdr<3 || (int)szHdr>m.n) ){
     goto idx_rowid_corruption;
   }
 
@@ -47263,8 +61218,8 @@ SQLITE_PRIVATE int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
     goto idx_rowid_corruption;
   }
   lenRowid = sqlite3VdbeSerialTypeLen(typeRowid);
-  testcase( m.n-lenRowid==szHdr );
-  if( unlikely(m.n-lenRowid<szHdr) ){
+  testcase( (u32)m.n==szHdr+lenRowid );
+  if( unlikely((u32)m.n<szHdr+lenRowid) ){
     goto idx_rowid_corruption;
   }
 
@@ -47283,22 +61238,19 @@ idx_rowid_corruption:
 }
 
 /*
-** Compare the key of the index entry that cursor pC is point to against
-** the key string in pKey (of length nKey).  Write into *pRes a number
+** Compare the key of the index entry that cursor pC is pointing to against
+** the key string in pUnpacked.  Write into *pRes a number
 ** that is negative, zero, or positive if pC is less than, equal to,
-** or greater than pKey.  Return SQLITE_OK on success.
+** or greater than pUnpacked.  Return SQLITE_OK on success.
 **
-** pKey is either created without a rowid or is truncated so that it
+** pUnpacked is either created without a rowid or is truncated so that it
 ** omits the rowid at the end.  The rowid at the end of the index entry
 ** is ignored as well.  Hence, this routine only compares the prefixes 
 ** of the keys prior to the final rowid, not the entire key.
-**
-** pUnpacked may be an unpacked version of pKey,nKey.  If pUnpacked is
-** supplied it is used in place of pKey,nKey.
 */
 SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(
   VdbeCursor *pC,             /* The cursor to compare against */
-  UnpackedRecord *pUnpacked,  /* Unpacked version of pKey and nKey */
+  UnpackedRecord *pUnpacked,  /* Unpacked version of key to compare against */
   int *res                    /* Write the comparison result here */
 ){
   i64 nCellKey = 0;
@@ -47306,19 +61258,21 @@ SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(
   BtCursor *pCur = pC->pCursor;
   Mem m;
 
-  sqlite3BtreeKeySize(pCur, &nCellKey);
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  VVA_ONLY(rc =) sqlite3BtreeKeySize(pCur, &nCellKey);
+  assert( rc==SQLITE_OK );    /* pCur is always valid so KeySize cannot fail */
+  /* nCellKey will always be between 0 and 0xffffffff because of the say
+  ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
   if( nCellKey<=0 || nCellKey>0x7fffffff ){
     *res = 0;
-    return SQLITE_OK;
+    return SQLITE_CORRUPT_BKPT;
   }
-  m.db = 0;
-  m.flags = 0;
-  m.zMalloc = 0;
+  memset(&m, 0, sizeof(m));
   rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, (int)nCellKey, 1, &m);
   if( rc ){
     return rc;
   }
-  assert( pUnpacked->flags & UNPACKED_IGNORE_ROWID );
+  assert( pUnpacked->flags & UNPACKED_PREFIX_MATCH );
   *res = sqlite3VdbeRecordCompare(m.n, m.z, pUnpacked);
   sqlite3VdbeMemRelease(&m);
   return SQLITE_OK;
@@ -47366,6 +61320,45 @@ SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe *v){
   return v->db;
 }
 
+/*
+** Return a pointer to an sqlite3_value structure containing the value bound
+** parameter iVar of VM v. Except, if the value is an SQL NULL, return 
+** 0 instead. Unless it is NULL, apply affinity aff (one of the SQLITE_AFF_*
+** constants) to the value before returning it.
+**
+** The returned value must be freed by the caller using sqlite3ValueFree().
+*/
+SQLITE_PRIVATE sqlite3_value *sqlite3VdbeGetValue(Vdbe *v, int iVar, u8 aff){
+  assert( iVar>0 );
+  if( v ){
+    Mem *pMem = &v->aVar[iVar-1];
+    if( 0==(pMem->flags & MEM_Null) ){
+      sqlite3_value *pRet = sqlite3ValueNew(v->db);
+      if( pRet ){
+        sqlite3VdbeMemCopy((Mem *)pRet, pMem);
+        sqlite3ValueApplyAffinity(pRet, aff, SQLITE_UTF8);
+        sqlite3VdbeMemStoreType((Mem *)pRet);
+      }
+      return pRet;
+    }
+  }
+  return 0;
+}
+
+/*
+** Configure SQL variable iVar so that binding a new value to it signals
+** to sqlite3_reoptimize() that re-preparing the statement may result
+** in a better query plan.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetVarmask(Vdbe *v, int iVar){
+  assert( iVar>0 );
+  if( iVar>32 ){
+    v->expmask = 0xffffffff;
+  }else{
+    v->expmask |= ((u32)1 << (iVar-1));
+  }
+}
+
 /************** End of vdbeaux.c *********************************************/
 /************** Begin file vdbeapi.c *****************************************/
 /*
@@ -47382,166 +61375,8 @@ SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe *v){
 **
 ** This file contains code use to implement APIs that are part of the
 ** VDBE.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
-#if 0 && defined(SQLITE_ENABLE_MEMORY_MANAGEMENT)
-/*
-** The following structure contains pointers to the end points of a
-** doubly-linked list of all compiled SQL statements that may be holding
-** buffers eligible for release when the sqlite3_release_memory() interface is
-** invoked. Access to this list is protected by the SQLITE_MUTEX_STATIC_LRU2
-** mutex.
-**
-** Statements are added to the end of this list when sqlite3_reset() is
-** called. They are removed either when sqlite3_step() or sqlite3_finalize()
-** is called. When statements are added to this list, the associated 
-** register array (p->aMem[1..p->nMem]) may contain dynamic buffers that
-** can be freed using sqlite3VdbeReleaseMemory().
-**
-** When statements are added or removed from this list, the mutex
-** associated with the Vdbe being added or removed (Vdbe.db->mutex) is
-** already held. The LRU2 mutex is then obtained, blocking if necessary,
-** the linked-list pointers manipulated and the LRU2 mutex relinquished.
-*/
-struct StatementLruList {
-  Vdbe *pFirst;
-  Vdbe *pLast;
-};
-static struct StatementLruList sqlite3LruStatements;
-
-/*
-** Check that the list looks to be internally consistent. This is used
-** as part of an assert() statement as follows:
-**
-**   assert( stmtLruCheck() );
-*/
-#ifndef NDEBUG
-static int stmtLruCheck(){
-  Vdbe *p;
-  for(p=sqlite3LruStatements.pFirst; p; p=p->pLruNext){
-    assert(p->pLruNext || p==sqlite3LruStatements.pLast);
-    assert(!p->pLruNext || p->pLruNext->pLruPrev==p);
-    assert(p->pLruPrev || p==sqlite3LruStatements.pFirst);
-    assert(!p->pLruPrev || p->pLruPrev->pLruNext==p);
-  }
-  return 1;
-}
-#endif
-
-/*
-** Add vdbe p to the end of the statement lru list. It is assumed that
-** p is not already part of the list when this is called. The lru list
-** is protected by the SQLITE_MUTEX_STATIC_LRU mutex.
-*/
-static void stmtLruAdd(Vdbe *p){
-  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU2));
-
-  if( p->pLruPrev || p->pLruNext || sqlite3LruStatements.pFirst==p ){
-    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU2));
-    return;
-  }
-
-  assert( stmtLruCheck() );
-
-  if( !sqlite3LruStatements.pFirst ){
-    assert( !sqlite3LruStatements.pLast );
-    sqlite3LruStatements.pFirst = p;
-    sqlite3LruStatements.pLast = p;
-  }else{
-    assert( !sqlite3LruStatements.pLast->pLruNext );
-    p->pLruPrev = sqlite3LruStatements.pLast;
-    sqlite3LruStatements.pLast->pLruNext = p;
-    sqlite3LruStatements.pLast = p;
-  }
-
-  assert( stmtLruCheck() );
-
-  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU2));
-}
-
-/*
-** Assuming the SQLITE_MUTEX_STATIC_LRU2 mutext is already held, remove
-** statement p from the least-recently-used statement list. If the 
-** statement is not currently part of the list, this call is a no-op.
-*/
-static void stmtLruRemoveNomutex(Vdbe *p){
-  if( p->pLruPrev || p->pLruNext || p==sqlite3LruStatements.pFirst ){
-    assert( stmtLruCheck() );
-    if( p->pLruNext ){
-      p->pLruNext->pLruPrev = p->pLruPrev;
-    }else{
-      sqlite3LruStatements.pLast = p->pLruPrev;
-    }
-    if( p->pLruPrev ){
-      p->pLruPrev->pLruNext = p->pLruNext;
-    }else{
-      sqlite3LruStatements.pFirst = p->pLruNext;
-    }
-    p->pLruNext = 0;
-    p->pLruPrev = 0;
-    assert( stmtLruCheck() );
-  }
-}
-
-/*
-** Assuming the SQLITE_MUTEX_STATIC_LRU2 mutext is not held, remove
-** statement p from the least-recently-used statement list. If the 
-** statement is not currently part of the list, this call is a no-op.
-*/
-static void stmtLruRemove(Vdbe *p){
-  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU2));
-  stmtLruRemoveNomutex(p);
-  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU2));
-}
-
-/*
-** Try to release n bytes of memory by freeing buffers associated 
-** with the memory registers of currently unused vdbes.
-*/
-SQLITE_PRIVATE int sqlite3VdbeReleaseMemory(int n){
-  Vdbe *p;
-  Vdbe *pNext;
-  int nFree = 0;
-
-  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU2));
-  for(p=sqlite3LruStatements.pFirst; p && nFree<n; p=pNext){
-    pNext = p->pLruNext;
-
-    /* For each statement handle in the lru list, attempt to obtain the
-    ** associated database mutex. If it cannot be obtained, continue
-    ** to the next statement handle. It is not possible to block on
-    ** the database mutex - that could cause deadlock.
-    */
-    if( SQLITE_OK==sqlite3_mutex_try(p->db->mutex) ){
-      nFree += sqlite3VdbeReleaseBuffers(p);
-      stmtLruRemoveNomutex(p);
-      sqlite3_mutex_leave(p->db->mutex);
-    }
-  }
-  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU2));
-
-  return nFree;
-}
-
-/*
-** Call sqlite3Reprepare() on the statement. Remove it from the
-** lru list before doing so, as Reprepare() will free all the
-** memory register buffers anyway.
-*/
-int vdbeReprepare(Vdbe *p){
-  stmtLruRemove(p);
-  return sqlite3Reprepare(p);
-}
-
-#else       /* !SQLITE_ENABLE_MEMORY_MANAGEMENT */
-  #define stmtLruRemove(x)
-  #define stmtLruAdd(x)
-  #define vdbeReprepare(x) sqlite3Reprepare(x)
-#endif
-
-
 #ifndef SQLITE_OMIT_DEPRECATED
 /*
 ** Return TRUE (non-zero) of the statement supplied as an argument needs
@@ -47557,6 +61392,28 @@ SQLITE_API int sqlite3_expired(sqlite3_stmt *pStmt){
 }
 #endif
 
+/*
+** Check on a Vdbe to make sure it has not been finalized.  Log
+** an error and return true if it has been finalized (or is otherwise
+** invalid).  Return false if it is ok.
+*/
+static int vdbeSafety(Vdbe *p){
+  if( p->db==0 ){
+    sqlite3_log(SQLITE_MISUSE, "API called with finalized prepared statement");
+    return 1;
+  }else{
+    return 0;
+  }
+}
+static int vdbeSafetyNotNull(Vdbe *p){
+  if( p==0 ){
+    sqlite3_log(SQLITE_MISUSE, "API called with NULL prepared statement");
+    return 1;
+  }else{
+    return vdbeSafety(p);
+  }
+}
+
 /*
 ** The following routine destroys a virtual machine that is created by
 ** the sqlite3_compile() routine. The integer returned is an SQLITE_
@@ -47569,16 +61426,17 @@ SQLITE_API int sqlite3_expired(sqlite3_stmt *pStmt){
 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt){
   int rc;
   if( pStmt==0 ){
+    /* IMPLEMENTATION-OF: R-57228-12904 Invoking sqlite3_finalize() on a NULL
+    ** pointer is a harmless no-op. */
     rc = SQLITE_OK;
   }else{
     Vdbe *v = (Vdbe*)pStmt;
-#if SQLITE_THREADSAFE
-    sqlite3_mutex *mutex = v->db->mutex;
-#endif
-    sqlite3_mutex_enter(mutex);
-    stmtLruRemove(v);
+    sqlite3 *db = v->db;
+    if( vdbeSafety(v) ) return SQLITE_MISUSE_BKPT;
+    sqlite3_mutex_enter(db->mutex);
     rc = sqlite3VdbeFinalize(v);
-    sqlite3_mutex_leave(mutex);
+    rc = sqlite3ApiExit(db, rc);
+    sqlite3LeaveMutexAndCloseZombie(db);
   }
   return rc;
 }
@@ -47599,9 +61457,9 @@ SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt){
     Vdbe *v = (Vdbe*)pStmt;
     sqlite3_mutex_enter(v->db->mutex);
     rc = sqlite3VdbeReset(v);
-    stmtLruAdd(v);
-    sqlite3VdbeMakeReady(v, -1, 0, 0, 0);
+    sqlite3VdbeRewind(v);
     assert( (rc & (v->db->errMask))==rc );
+    rc = sqlite3ApiExit(v->db, rc);
     sqlite3_mutex_leave(v->db->mutex);
   }
   return rc;
@@ -47622,6 +61480,9 @@ SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt *pStmt){
     sqlite3VdbeMemRelease(&p->aVar[i]);
     p->aVar[i].flags = MEM_Null;
   }
+  if( p->isPrepareV2 && p->expmask ){
+    p->expired = 1;
+  }
   sqlite3_mutex_leave(mutex);
   return rc;
 }
@@ -47637,7 +61498,7 @@ SQLITE_API const void *sqlite3_value_blob(sqlite3_value *pVal){
     sqlite3VdbeMemExpandBlob(p);
     p->flags &= ~MEM_Str;
     p->flags |= MEM_Blob;
-    return p->z;
+    return p->n ? p->z : 0;
   }else{
     return sqlite3_value_text(pVal);
   }
@@ -47678,7 +61539,22 @@ SQLITE_API int sqlite3_value_type(sqlite3_value* pVal){
 /**************************** sqlite3_result_  *******************************
 ** The following routines are used by user-defined functions to specify
 ** the function result.
+**
+** The setStrOrError() funtion calls sqlite3VdbeMemSetStr() to store the
+** result as a string or blob but if the string or blob is too large, it
+** then sets the error code to SQLITE_TOOBIG
 */
+static void setResultStrOrError(
+  sqlite3_context *pCtx,  /* Function context */
+  const char *z,          /* String pointer */
+  int n,                  /* Bytes in string, or negative */
+  u8 enc,                 /* Encoding of z.  0 for BLOBs */
+  void (*xDel)(void*)     /* Destructor function */
+){
+  if( sqlite3VdbeMemSetStr(&pCtx->s, z, n, enc, xDel)==SQLITE_TOOBIG ){
+    sqlite3_result_error_toobig(pCtx);
+  }
+}
 SQLITE_API void sqlite3_result_blob(
   sqlite3_context *pCtx, 
   const void *z, 
@@ -47687,7 +61563,7 @@ SQLITE_API void sqlite3_result_blob(
 ){
   assert( n>=0 );
   assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
-  sqlite3VdbeMemSetStr(&pCtx->s, z, n, 0, xDel);
+  setResultStrOrError(pCtx, z, n, 0, xDel);
 }
 SQLITE_API void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
   assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
@@ -47724,7 +61600,7 @@ SQLITE_API void sqlite3_result_text(
   void (*xDel)(void *)
 ){
   assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
-  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF8, xDel);
+  setResultStrOrError(pCtx, z, n, SQLITE_UTF8, xDel);
 }
 #ifndef SQLITE_OMIT_UTF16
 SQLITE_API void sqlite3_result_text16(
@@ -47734,7 +61610,7 @@ SQLITE_API void sqlite3_result_text16(
   void (*xDel)(void *)
 ){
   assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
-  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16NATIVE, xDel);
+  setResultStrOrError(pCtx, z, n, SQLITE_UTF16NATIVE, xDel);
 }
 SQLITE_API void sqlite3_result_text16be(
   sqlite3_context *pCtx, 
@@ -47743,7 +61619,7 @@ SQLITE_API void sqlite3_result_text16be(
   void (*xDel)(void *)
 ){
   assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
-  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16BE, xDel);
+  setResultStrOrError(pCtx, z, n, SQLITE_UTF16BE, xDel);
 }
 SQLITE_API void sqlite3_result_text16le(
   sqlite3_context *pCtx, 
@@ -47752,7 +61628,7 @@ SQLITE_API void sqlite3_result_text16le(
   void (*xDel)(void *)
 ){
   assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
-  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16LE, xDel);
+  setResultStrOrError(pCtx, z, n, SQLITE_UTF16LE, xDel);
 }
 #endif /* SQLITE_OMIT_UTF16 */
 SQLITE_API void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
@@ -47765,6 +61641,10 @@ SQLITE_API void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
 }
 SQLITE_API void sqlite3_result_error_code(sqlite3_context *pCtx, int errCode){
   pCtx->isError = errCode;
+  if( pCtx->s.flags & MEM_Null ){
+    sqlite3VdbeMemSetStr(&pCtx->s, sqlite3ErrStr(errCode), -1, 
+                         SQLITE_UTF8, SQLITE_STATIC);
+  }
 }
 
 /* Force an SQLITE_TOOBIG error. */
@@ -47783,6 +61663,27 @@ SQLITE_API void sqlite3_result_error_nomem(sqlite3_context *pCtx){
   pCtx->s.db->mallocFailed = 1;
 }
 
+/*
+** This function is called after a transaction has been committed. It 
+** invokes callbacks registered with sqlite3_wal_hook() as required.
+*/
+static int doWalCallbacks(sqlite3 *db){
+  int rc = SQLITE_OK;
+#ifndef SQLITE_OMIT_WAL
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      int nEntry = sqlite3PagerWalCallback(sqlite3BtreePager(pBt));
+      if( db->xWalCallback && nEntry>0 && rc==SQLITE_OK ){
+        rc = db->xWalCallback(db->pWalArg, db, db->aDb[i].zName, nEntry);
+      }
+    }
+  }
+#endif
+  return rc;
+}
+
 /*
 ** Execute the statement pStmt, either until a row of data is ready, the
 ** statement is completely executed or an error occurs.
@@ -47798,26 +61699,45 @@ static int sqlite3Step(Vdbe *p){
 
   assert(p);
   if( p->magic!=VDBE_MAGIC_RUN ){
-    return SQLITE_MISUSE;
+    /* We used to require that sqlite3_reset() be called before retrying
+    ** sqlite3_step() after any error or after SQLITE_DONE.  But beginning
+    ** with version 3.7.0, we changed this so that sqlite3_reset() would
+    ** be called automatically instead of throwing the SQLITE_MISUSE error.
+    ** This "automatic-reset" change is not technically an incompatibility, 
+    ** since any application that receives an SQLITE_MISUSE is broken by
+    ** definition.
+    **
+    ** Nevertheless, some published applications that were originally written
+    ** for version 3.6.23 or earlier do in fact depend on SQLITE_MISUSE 
+    ** returns, and those were broken by the automatic-reset change.  As a
+    ** a work-around, the SQLITE_OMIT_AUTORESET compile-time restores the
+    ** legacy behavior of returning SQLITE_MISUSE for cases where the 
+    ** previous sqlite3_step() returned something other than a SQLITE_LOCKED
+    ** or SQLITE_BUSY error.
+    */
+#ifdef SQLITE_OMIT_AUTORESET
+    if( p->rc==SQLITE_BUSY || p->rc==SQLITE_LOCKED ){
+      sqlite3_reset((sqlite3_stmt*)p);
+    }else{
+      return SQLITE_MISUSE_BKPT;
+    }
+#else
+    sqlite3_reset((sqlite3_stmt*)p);
+#endif
   }
 
-  /* Assert that malloc() has not failed */
+  /* Check that malloc() has not failed. If it has, return early. */
   db = p->db;
   if( db->mallocFailed ){
+    p->rc = SQLITE_NOMEM;
     return SQLITE_NOMEM;
   }
 
   if( p->pc<=0 && p->expired ){
-    if( p->rc==SQLITE_OK ){
-      p->rc = SQLITE_SCHEMA;
-    }
+    p->rc = SQLITE_SCHEMA;
     rc = SQLITE_ERROR;
     goto end_of_step;
   }
-  if( sqlite3SafetyOn(db) ){
-    p->rc = SQLITE_MISUSE;
-    return SQLITE_MISUSE;
-  }
   if( p->pc<0 ){
     /* If there are no other statements currently running, then
     ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
@@ -47827,18 +61747,17 @@ static int sqlite3Step(Vdbe *p){
       db->u1.isInterrupted = 0;
     }
 
+    assert( db->writeVdbeCnt>0 || db->autoCommit==0 || db->nDeferredCons==0 );
+
 #ifndef SQLITE_OMIT_TRACE
     if( db->xProfile && !db->init.busy ){
-      double rNow;
-      sqlite3OsCurrentTime(db->pVfs, &rNow);
-      p->startTime = (u64)((rNow - (int)rNow)*3600.0*24.0*1000000000.0);
+      sqlite3OsCurrentTimeInt64(db->pVfs, &p->startTime);
     }
 #endif
 
     db->activeVdbeCnt++;
     if( p->readOnly==0 ) db->writeVdbeCnt++;
     p->pc = 0;
-    stmtLruRemove(p);
   }
 #ifndef SQLITE_OMIT_EXPLAIN
   if( p->explain ){
@@ -47846,101 +61765,109 @@ static int sqlite3Step(Vdbe *p){
   }else
 #endif /* SQLITE_OMIT_EXPLAIN */
   {
+    db->vdbeExecCnt++;
     rc = sqlite3VdbeExec(p);
-  }
-
-  if( sqlite3SafetyOff(db) ){
-    rc = SQLITE_MISUSE;
+    db->vdbeExecCnt--;
   }
 
 #ifndef SQLITE_OMIT_TRACE
   /* Invoke the profile callback if there is one
   */
-  if( rc!=SQLITE_ROW && db->xProfile && !db->init.busy && p->nOp>0
-           && p->aOp[0].opcode==OP_Trace && p->aOp[0].p4.z!=0 ){
-    double rNow;
-    u64 elapseTime;
-
-    sqlite3OsCurrentTime(db->pVfs, &rNow);
-    elapseTime = (u64)((rNow - (int)rNow)*3600.0*24.0*1000000000.0);
-    elapseTime -= p->startTime;
-    db->xProfile(db->pProfileArg, p->aOp[0].p4.z, elapseTime);
+  if( rc!=SQLITE_ROW && db->xProfile && !db->init.busy && p->zSql ){
+    sqlite3_int64 iNow;
+    sqlite3OsCurrentTimeInt64(db->pVfs, &iNow);
+    db->xProfile(db->pProfileArg, p->zSql, (iNow - p->startTime)*1000000);
   }
 #endif
 
-  db->errCode = rc;
-  /*sqlite3Error(p->db, rc, 0);*/
-  p->rc = sqlite3ApiExit(p->db, p->rc);
-end_of_step:
-  assert( (rc&0xff)==rc );
-  if( p->zSql && (rc&0xff)<SQLITE_ROW ){
-    /* This behavior occurs if sqlite3_prepare_v2() was used to build
-    ** the prepared statement.  Return error codes directly */
-    p->db->errCode = p->rc;
-    /* sqlite3Error(p->db, p->rc, 0); */
-    return p->rc;
-  }else{
-    /* This is for legacy sqlite3_prepare() builds and when the code
-    ** is SQLITE_ROW or SQLITE_DONE */
-    return rc;
+  if( rc==SQLITE_DONE ){
+    assert( p->rc==SQLITE_OK );
+    p->rc = doWalCallbacks(db);
+    if( p->rc!=SQLITE_OK ){
+      rc = SQLITE_ERROR;
+    }
   }
+
+  db->errCode = rc;
+  if( SQLITE_NOMEM==sqlite3ApiExit(p->db, p->rc) ){
+    p->rc = SQLITE_NOMEM;
+  }
+end_of_step:
+  /* At this point local variable rc holds the value that should be 
+  ** returned if this statement was compiled using the legacy 
+  ** sqlite3_prepare() interface. According to the docs, this can only
+  ** be one of the values in the first assert() below. Variable p->rc 
+  ** contains the value that would be returned if sqlite3_finalize() 
+  ** were called on statement p.
+  */
+  assert( rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR 
+       || rc==SQLITE_BUSY || rc==SQLITE_MISUSE
+  );
+  assert( p->rc!=SQLITE_ROW && p->rc!=SQLITE_DONE );
+  if( p->isPrepareV2 && rc!=SQLITE_ROW && rc!=SQLITE_DONE ){
+    /* If this statement was prepared using sqlite3_prepare_v2(), and an
+    ** error has occured, then return the error code in p->rc to the
+    ** caller. Set the error code in the database handle to the same value.
+    */ 
+    rc = sqlite3VdbeTransferError(p);
+  }
+  return (rc&db->errMask);
 }
 
+/*
+** The maximum number of times that a statement will try to reparse
+** itself before giving up and returning SQLITE_SCHEMA.
+*/
+#ifndef SQLITE_MAX_SCHEMA_RETRY
+# define SQLITE_MAX_SCHEMA_RETRY 5
+#endif
+
 /*
 ** This is the top-level implementation of sqlite3_step().  Call
 ** sqlite3Step() to do most of the work.  If a schema error occurs,
 ** call sqlite3Reprepare() and try again.
 */
-#ifdef SQLITE_OMIT_PARSER
 SQLITE_API int sqlite3_step(sqlite3_stmt *pStmt){
-  int rc = SQLITE_MISUSE;
-  if( pStmt ){
-    Vdbe *v;
-    v = (Vdbe*)pStmt;
-    sqlite3_mutex_enter(v->db->mutex);
-    rc = sqlite3Step(v);
-    sqlite3_mutex_leave(v->db->mutex);
+  int rc = SQLITE_OK;      /* Result from sqlite3Step() */
+  int rc2 = SQLITE_OK;     /* Result from sqlite3Reprepare() */
+  Vdbe *v = (Vdbe*)pStmt;  /* the prepared statement */
+  int cnt = 0;             /* Counter to prevent infinite loop of reprepares */
+  sqlite3 *db;             /* The database connection */
+
+  if( vdbeSafetyNotNull(v) ){
+    return SQLITE_MISUSE_BKPT;
   }
+  db = v->db;
+  sqlite3_mutex_enter(db->mutex);
+  while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
+         && cnt++ < SQLITE_MAX_SCHEMA_RETRY
+         && (rc2 = rc = sqlite3Reprepare(v))==SQLITE_OK ){
+    sqlite3_reset(pStmt);
+    assert( v->expired==0 );
+  }
+  if( rc2!=SQLITE_OK && ALWAYS(v->isPrepareV2) && ALWAYS(db->pErr) ){
+    /* This case occurs after failing to recompile an sql statement. 
+    ** The error message from the SQL compiler has already been loaded 
+    ** into the database handle. This block copies the error message 
+    ** from the database handle into the statement and sets the statement
+    ** program counter to 0 to ensure that when the statement is 
+    ** finalized or reset the parser error message is available via
+    ** sqlite3_errmsg() and sqlite3_errcode().
+    */
+    const char *zErr = (const char *)sqlite3_value_text(db->pErr); 
+    sqlite3DbFree(db, v->zErrMsg);
+    if( !db->mallocFailed ){
+      v->zErrMsg = sqlite3DbStrDup(db, zErr);
+      v->rc = rc2;
+    } else {
+      v->zErrMsg = 0;
+      v->rc = rc = SQLITE_NOMEM;
+    }
+  }
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
   return rc;
 }
-#else
-SQLITE_API int sqlite3_step(sqlite3_stmt *pStmt){
-  int rc = SQLITE_MISUSE;
-  if( pStmt ){
-    int cnt = 0;
-    Vdbe *v = (Vdbe*)pStmt;
-    sqlite3 *db = v->db;
-    sqlite3_mutex_enter(db->mutex);
-    while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
-           && cnt++ < 5
-           && vdbeReprepare(v) ){
-      sqlite3_reset(pStmt);
-      v->expired = 0;
-    }
-    if( rc==SQLITE_SCHEMA && v->zSql && db->pErr ){
-      /* This case occurs after failing to recompile an sql statement. 
-      ** The error message from the SQL compiler has already been loaded 
-      ** into the database handle. This block copies the error message 
-      ** from the database handle into the statement and sets the statement
-      ** program counter to 0 to ensure that when the statement is 
-      ** finalized or reset the parser error message is available via
-      ** sqlite3_errmsg() and sqlite3_errcode().
-      */
-      const char *zErr = (const char *)sqlite3_value_text(db->pErr); 
-      sqlite3DbFree(db, v->zErrMsg);
-      if( !db->mallocFailed ){
-        v->zErrMsg = sqlite3DbStrDup(db, zErr);
-      } else {
-        v->zErrMsg = 0;
-        v->rc = SQLITE_NOMEM;
-      }
-    }
-    rc = sqlite3ApiExit(db, rc);
-    sqlite3_mutex_leave(db->mutex);
-  }
-  return rc;
-}
-#endif
 
 /*
 ** Extract the user data from a sqlite3_context structure and return a
@@ -47954,6 +61881,12 @@ SQLITE_API void *sqlite3_user_data(sqlite3_context *p){
 /*
 ** Extract the user data from a sqlite3_context structure and return a
 ** pointer to it.
+**
+** IMPLEMENTATION-OF: R-46798-50301 The sqlite3_context_db_handle() interface
+** returns a copy of the pointer to the database connection (the 1st
+** parameter) of the sqlite3_create_function() and
+** sqlite3_create_function16() routines that originally registered the
+** application defined function.
 */
 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context *p){
   assert( p && p->pFunc );
@@ -47976,7 +61909,7 @@ SQLITE_PRIVATE void sqlite3InvalidFunction(
   const char *zName = context->pFunc->zName;
   char *zErr;
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
-  zErr = sqlite3MPrintf(0,
+  zErr = sqlite3_mprintf(
       "unable to use function %s in the requested context", zName);
   sqlite3_result_error(context, zErr, -1);
   sqlite3_free(zErr);
@@ -47992,8 +61925,9 @@ SQLITE_API void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){
   assert( p && p->pFunc && p->pFunc->xStep );
   assert( sqlite3_mutex_held(p->s.db->mutex) );
   pMem = p->pMem;
+  testcase( nByte<0 );
   if( (pMem->flags & MEM_Agg)==0 ){
-    if( nByte==0 ){
+    if( nByte<=0 ){
       sqlite3VdbeMemReleaseExternal(pMem);
       pMem->flags = MEM_Null;
       pMem->z = 0;
@@ -48079,7 +62013,7 @@ failed:
 ** context.
 */
 SQLITE_API int sqlite3_aggregate_count(sqlite3_context *p){
-  assert( p && p->pFunc && p->pFunc->xStep );
+  assert( p && p->pMem && p->pFunc && p->pFunc->xStep );
   return p->pMem->n;
 }
 #endif
@@ -48111,17 +62045,35 @@ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt){
 */
 static Mem *columnMem(sqlite3_stmt *pStmt, int i){
   Vdbe *pVm;
-  int vals;
   Mem *pOut;
 
   pVm = (Vdbe *)pStmt;
   if( pVm && pVm->pResultSet!=0 && i<pVm->nResColumn && i>=0 ){
     sqlite3_mutex_enter(pVm->db->mutex);
-    vals = sqlite3_data_count(pStmt);
     pOut = &pVm->pResultSet[i];
   }else{
-    static const Mem nullMem = {{0}, 0.0, 0, "", 0, MEM_Null, SQLITE_NULL, 0, 0, 0 };
-    if( pVm->db ){
+    /* If the value passed as the second argument is out of range, return
+    ** a pointer to the following static Mem object which contains the
+    ** value SQL NULL. Even though the Mem structure contains an element
+    ** of type i64, on certain architectures (x86) with certain compiler
+    ** switches (-Os), gcc may align this Mem object on a 4-byte boundary
+    ** instead of an 8-byte one. This all works fine, except that when
+    ** running with SQLITE_DEBUG defined the SQLite code sometimes assert()s
+    ** that a Mem structure is located on an 8-byte boundary. To prevent
+    ** these assert()s from failing, when building with SQLITE_DEBUG defined
+    ** using gcc, we force nullMem to be 8-byte aligned using the magical
+    ** __attribute__((aligned(8))) macro.  */
+    static const Mem nullMem 
+#if defined(SQLITE_DEBUG) && defined(__GNUC__)
+      __attribute__((aligned(8))) 
+#endif
+      = {0, "", (double)0, {0}, 0, MEM_Null, SQLITE_NULL, 0,
+#ifdef SQLITE_DEBUG
+         0, 0,  /* pScopyFrom, pFiller */
+#endif
+         0, 0 };
+
+    if( pVm && ALWAYS(pVm->db) ){
       sqlite3_mutex_enter(pVm->db->mutex);
       sqlite3Error(pVm->db, SQLITE_RANGE, 0);
     }
@@ -48146,8 +62098,7 @@ static Mem *columnMem(sqlite3_stmt *pStmt, int i){
 **     sqlite3_column_real()
 **     sqlite3_column_bytes()
 **     sqlite3_column_bytes16()
-**
-** But not for sqlite3_column_blob(), which never calls malloc().
+**     sqiite3_column_blob()
 */
 static void columnMallocFailure(sqlite3_stmt *pStmt)
 {
@@ -48261,24 +62212,23 @@ static const void *columnName(
   const void *ret = 0;
   Vdbe *p = (Vdbe *)pStmt;
   int n;
+  sqlite3 *db = p->db;
   
-
-  if( p!=0 ){
-    n = sqlite3_column_count(pStmt);
-    if( N<n && N>=0 ){
-      N += useType*n;
-      sqlite3_mutex_enter(p->db->mutex);
-      ret = xFunc(&p->aColName[N]);
-
-      /* A malloc may have failed inside of the xFunc() call. If this
-      ** is the case, clear the mallocFailed flag and return NULL.
-      */
-      if( p->db && p->db->mallocFailed ){
-        p->db->mallocFailed = 0;
-        ret = 0;
-      }
-      sqlite3_mutex_leave(p->db->mutex);
+  assert( db!=0 );
+  n = sqlite3_column_count(pStmt);
+  if( N<n && N>=0 ){
+    N += useType*n;
+    sqlite3_mutex_enter(db->mutex);
+    assert( db->mallocFailed==0 );
+    ret = xFunc(&p->aColName[N]);
+     /* A malloc may have failed inside of the xFunc() call. If this
+    ** is the case, clear the mallocFailed flag and return NULL.
+    */
+    if( db->mallocFailed ){
+      db->mallocFailed = 0;
+      ret = 0;
     }
+    sqlite3_mutex_leave(db->mutex);
   }
   return ret;
 }
@@ -48392,12 +62342,16 @@ SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt *pStmt, int N){
 */
 static int vdbeUnbind(Vdbe *p, int i){
   Mem *pVar;
-  if( p==0 ) return SQLITE_MISUSE;
+  if( vdbeSafetyNotNull(p) ){
+    return SQLITE_MISUSE_BKPT;
+  }
   sqlite3_mutex_enter(p->db->mutex);
   if( p->magic!=VDBE_MAGIC_RUN || p->pc>=0 ){
     sqlite3Error(p->db, SQLITE_MISUSE, 0);
     sqlite3_mutex_leave(p->db->mutex);
-    return SQLITE_MISUSE;
+    sqlite3_log(SQLITE_MISUSE, 
+        "bind on a busy prepared statement: [%s]", p->zSql);
+    return SQLITE_MISUSE_BKPT;
   }
   if( i<1 || i>p->nVar ){
     sqlite3Error(p->db, SQLITE_RANGE, 0);
@@ -48409,6 +62363,21 @@ static int vdbeUnbind(Vdbe *p, int i){
   sqlite3VdbeMemRelease(pVar);
   pVar->flags = MEM_Null;
   sqlite3Error(p->db, SQLITE_OK, 0);
+
+  /* If the bit corresponding to this variable in Vdbe.expmask is set, then 
+  ** binding a new value to this variable invalidates the current query plan.
+  **
+  ** IMPLEMENTATION-OF: R-48440-37595 If the specific value bound to host
+  ** parameter in the WHERE clause might influence the choice of query plan
+  ** for a statement, then the statement will be automatically recompiled,
+  ** as if there had been a schema change, on the first sqlite3_step() call
+  ** following any change to the bindings of that parameter.
+  */
+  if( p->isPrepareV2 &&
+     ((i<32 && p->expmask & ((u32)1 << i)) || p->expmask==0xffffffff)
+  ){
+    p->expired = 1;
+  }
   return SQLITE_OK;
 }
 
@@ -48439,6 +62408,8 @@ static int bindText(
       rc = sqlite3ApiExit(p->db, rc);
     }
     sqlite3_mutex_leave(p->db->mutex);
+  }else if( xDel!=SQLITE_STATIC && xDel!=SQLITE_TRANSIENT ){
+    xDel((void*)zData);
   }
   return rc;
 }
@@ -48510,16 +62481,33 @@ SQLITE_API int sqlite3_bind_text16(
 #endif /* SQLITE_OMIT_UTF16 */
 SQLITE_API int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
   int rc;
-  Vdbe *p = (Vdbe *)pStmt;
-  rc = vdbeUnbind(p, i);
-  if( rc==SQLITE_OK ){
-    rc = sqlite3VdbeMemCopy(&p->aVar[i-1], pValue);
-    if( rc==SQLITE_OK ){
-      rc = sqlite3VdbeChangeEncoding(&p->aVar[i-1], ENC(p->db));
+  switch( pValue->type ){
+    case SQLITE_INTEGER: {
+      rc = sqlite3_bind_int64(pStmt, i, pValue->u.i);
+      break;
+    }
+    case SQLITE_FLOAT: {
+      rc = sqlite3_bind_double(pStmt, i, pValue->r);
+      break;
+    }
+    case SQLITE_BLOB: {
+      if( pValue->flags & MEM_Zero ){
+        rc = sqlite3_bind_zeroblob(pStmt, i, pValue->u.nZero);
+      }else{
+        rc = sqlite3_bind_blob(pStmt, i, pValue->z, pValue->n,SQLITE_TRANSIENT);
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      rc = bindText(pStmt,i,  pValue->z, pValue->n, SQLITE_TRANSIENT,
+                              pValue->enc);
+      break;
+    }
+    default: {
+      rc = sqlite3_bind_null(pStmt, i);
+      break;
     }
-    sqlite3_mutex_leave(p->db->mutex);
   }
-  rc = sqlite3ApiExit(p->db, rc);
   return rc;
 }
 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt *pStmt, int i, int n){
@@ -48542,29 +62530,6 @@ SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){
   return p ? p->nVar : 0;
 }
 
-/*
-** Create a mapping from variable numbers to variable names
-** in the Vdbe.azVar[] array, if such a mapping does not already
-** exist.
-*/
-static void createVarMap(Vdbe *p){
-  if( !p->okVar ){
-    sqlite3_mutex_enter(p->db->mutex);
-    if( !p->okVar ){
-      int j;
-      Op *pOp;
-      for(j=0, pOp=p->aOp; j<p->nOp; j++, pOp++){
-        if( pOp->opcode==OP_Variable ){
-          assert( pOp->p1>0 && pOp->p1<=p->nVar );
-          p->azVar[pOp->p1-1] = pOp->p4.z;
-        }
-      }
-      p->okVar = 1;
-    }
-    sqlite3_mutex_leave(p->db->mutex);
-  }
-}
-
 /*
 ** Return the name of a wildcard parameter.  Return NULL if the index
 ** is out of range or if the wildcard is unnamed.
@@ -48573,10 +62538,9 @@ static void createVarMap(Vdbe *p){
 */
 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
   Vdbe *p = (Vdbe*)pStmt;
-  if( p==0 || i<1 || i>p->nVar ){
+  if( p==0 || i<1 || i>p->nzVar ){
     return 0;
   }
-  createVarMap(p);
   return p->azVar[i-1];
 }
 
@@ -48585,56 +62549,67 @@ SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
 ** with that name.  If there is no variable with the given name,
 ** return 0.
 */
-SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt *pStmt, const char *zName){
-  Vdbe *p = (Vdbe*)pStmt;
+SQLITE_PRIVATE int sqlite3VdbeParameterIndex(Vdbe *p, const char *zName, int nName){
   int i;
   if( p==0 ){
     return 0;
   }
-  createVarMap(p); 
   if( zName ){
-    for(i=0; i<p->nVar; i++){
+    for(i=0; i<p->nzVar; i++){
       const char *z = p->azVar[i];
-      if( z && strcmp(z,zName)==0 ){
+      if( z && memcmp(z,zName,nName)==0 && z[nName]==0 ){
         return i+1;
       }
     }
   }
   return 0;
 }
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt *pStmt, const char *zName){
+  return sqlite3VdbeParameterIndex((Vdbe*)pStmt, zName, sqlite3Strlen30(zName));
+}
 
 /*
 ** Transfer all bindings from the first statement over to the second.
-** If the two statements contain a different number of bindings, then
-** an SQLITE_ERROR is returned.
 */
 SQLITE_PRIVATE int sqlite3TransferBindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
   Vdbe *pFrom = (Vdbe*)pFromStmt;
   Vdbe *pTo = (Vdbe*)pToStmt;
-  int i, rc = SQLITE_OK;
-  if( (pFrom->magic!=VDBE_MAGIC_RUN && pFrom->magic!=VDBE_MAGIC_HALT)
-    || (pTo->magic!=VDBE_MAGIC_RUN && pTo->magic!=VDBE_MAGIC_HALT)
-    || pTo->db!=pFrom->db ){
-    return SQLITE_MISUSE;
-  }
-  if( pFrom->nVar!=pTo->nVar ){
-    return SQLITE_ERROR;
-  }
+  int i;
+  assert( pTo->db==pFrom->db );
+  assert( pTo->nVar==pFrom->nVar );
   sqlite3_mutex_enter(pTo->db->mutex);
-  for(i=0; rc==SQLITE_OK && i<pFrom->nVar; i++){
+  for(i=0; i<pFrom->nVar; i++){
     sqlite3VdbeMemMove(&pTo->aVar[i], &pFrom->aVar[i]);
   }
   sqlite3_mutex_leave(pTo->db->mutex);
-  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
-  return rc;
+  return SQLITE_OK;
 }
 
 #ifndef SQLITE_OMIT_DEPRECATED
 /*
 ** Deprecated external interface.  Internal/core SQLite code
 ** should call sqlite3TransferBindings.
+**
+** Is is misuse to call this routine with statements from different
+** database connections.  But as this is a deprecated interface, we
+** will not bother to check for that condition.
+**
+** If the two statements contain a different number of bindings, then
+** an SQLITE_ERROR is returned.  Nothing else can go wrong, so otherwise
+** SQLITE_OK is returned.
 */
 SQLITE_API int sqlite3_transfer_bindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
+  Vdbe *pFrom = (Vdbe*)pFromStmt;
+  Vdbe *pTo = (Vdbe*)pToStmt;
+  if( pFrom->nVar!=pTo->nVar ){
+    return SQLITE_ERROR;
+  }
+  if( pTo->isPrepareV2 && pTo->expmask ){
+    pTo->expired = 1;
+  }
+  if( pFrom->isPrepareV2 && pFrom->expmask ){
+    pFrom->expired = 1;
+  }
   return sqlite3TransferBindings(pFromStmt, pToStmt);
 }
 #endif
@@ -48649,6 +62624,22 @@ SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt *pStmt){
   return pStmt ? ((Vdbe*)pStmt)->db : 0;
 }
 
+/*
+** Return true if the prepared statement is guaranteed to not modify the
+** database.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->readOnly : 1;
+}
+
+/*
+** Return true if the prepared statement is in need of being reset.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt *pStmt){
+  Vdbe *v = (Vdbe*)pStmt;
+  return v!=0 && v->pc>0 && v->magic==VDBE_MAGIC_RUN;
+}
+
 /*
 ** Return a pointer to the next prepared statement after pStmt associated
 ** with database connection pDb.  If pStmt is NULL, return the first
@@ -48678,6 +62669,278 @@ SQLITE_API int sqlite3_stmt_status(sqlite3_stmt *pStmt, int op, int resetFlag){
 }
 
 /************** End of vdbeapi.c *********************************************/
+/************** Begin file vdbetrace.c ***************************************/
+/*
+** 2009 November 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to insert the values of host parameters
+** (aka "wildcards") into the SQL text output by sqlite3_trace().
+**
+** The Vdbe parse-tree explainer is also found here.
+*/
+
+#ifndef SQLITE_OMIT_TRACE
+
+/*
+** zSql is a zero-terminated string of UTF-8 SQL text.  Return the number of
+** bytes in this text up to but excluding the first character in
+** a host parameter.  If the text contains no host parameters, return
+** the total number of bytes in the text.
+*/
+static int findNextHostParameter(const char *zSql, int *pnToken){
+  int tokenType;
+  int nTotal = 0;
+  int n;
+
+  *pnToken = 0;
+  while( zSql[0] ){
+    n = sqlite3GetToken((u8*)zSql, &tokenType);
+    assert( n>0 && tokenType!=TK_ILLEGAL );
+    if( tokenType==TK_VARIABLE ){
+      *pnToken = n;
+      break;
+    }
+    nTotal += n;
+    zSql += n;
+  }
+  return nTotal;
+}
+
+/*
+** This function returns a pointer to a nul-terminated string in memory
+** obtained from sqlite3DbMalloc(). If sqlite3.vdbeExecCnt is 1, then the
+** string contains a copy of zRawSql but with host parameters expanded to 
+** their current bindings. Or, if sqlite3.vdbeExecCnt is greater than 1, 
+** then the returned string holds a copy of zRawSql with "-- " prepended
+** to each line of text.
+**
+** The calling function is responsible for making sure the memory returned
+** is eventually freed.
+**
+** ALGORITHM:  Scan the input string looking for host parameters in any of
+** these forms:  ?, ?N, $A, @A, :A.  Take care to avoid text within
+** string literals, quoted identifier names, and comments.  For text forms,
+** the host parameter index is found by scanning the perpared
+** statement for the corresponding OP_Variable opcode.  Once the host
+** parameter index is known, locate the value in p->aVar[].  Then render
+** the value as a literal in place of the host parameter name.
+*/
+SQLITE_PRIVATE char *sqlite3VdbeExpandSql(
+  Vdbe *p,                 /* The prepared statement being evaluated */
+  const char *zRawSql      /* Raw text of the SQL statement */
+){
+  sqlite3 *db;             /* The database connection */
+  int idx = 0;             /* Index of a host parameter */
+  int nextIndex = 1;       /* Index of next ? host parameter */
+  int n;                   /* Length of a token prefix */
+  int nToken;              /* Length of the parameter token */
+  int i;                   /* Loop counter */
+  Mem *pVar;               /* Value of a host parameter */
+  StrAccum out;            /* Accumulate the output here */
+  char zBase[100];         /* Initial working space */
+
+  db = p->db;
+  sqlite3StrAccumInit(&out, zBase, sizeof(zBase), 
+                      db->aLimit[SQLITE_LIMIT_LENGTH]);
+  out.db = db;
+  if( db->vdbeExecCnt>1 ){
+    while( *zRawSql ){
+      const char *zStart = zRawSql;
+      while( *(zRawSql++)!='\n' && *zRawSql );
+      sqlite3StrAccumAppend(&out, "-- ", 3);
+      sqlite3StrAccumAppend(&out, zStart, (int)(zRawSql-zStart));
+    }
+  }else{
+    while( zRawSql[0] ){
+      n = findNextHostParameter(zRawSql, &nToken);
+      assert( n>0 );
+      sqlite3StrAccumAppend(&out, zRawSql, n);
+      zRawSql += n;
+      assert( zRawSql[0] || nToken==0 );
+      if( nToken==0 ) break;
+      if( zRawSql[0]=='?' ){
+        if( nToken>1 ){
+          assert( sqlite3Isdigit(zRawSql[1]) );
+          sqlite3GetInt32(&zRawSql[1], &idx);
+        }else{
+          idx = nextIndex;
+        }
+      }else{
+        assert( zRawSql[0]==':' || zRawSql[0]=='$' || zRawSql[0]=='@' );
+        testcase( zRawSql[0]==':' );
+        testcase( zRawSql[0]=='$' );
+        testcase( zRawSql[0]=='@' );
+        idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
+        assert( idx>0 );
+      }
+      zRawSql += nToken;
+      nextIndex = idx + 1;
+      assert( idx>0 && idx<=p->nVar );
+      pVar = &p->aVar[idx-1];
+      if( pVar->flags & MEM_Null ){
+        sqlite3StrAccumAppend(&out, "NULL", 4);
+      }else if( pVar->flags & MEM_Int ){
+        sqlite3XPrintf(&out, "%lld", pVar->u.i);
+      }else if( pVar->flags & MEM_Real ){
+        sqlite3XPrintf(&out, "%!.15g", pVar->r);
+      }else if( pVar->flags & MEM_Str ){
+#ifndef SQLITE_OMIT_UTF16
+        u8 enc = ENC(db);
+        if( enc!=SQLITE_UTF8 ){
+          Mem utf8;
+          memset(&utf8, 0, sizeof(utf8));
+          utf8.db = db;
+          sqlite3VdbeMemSetStr(&utf8, pVar->z, pVar->n, enc, SQLITE_STATIC);
+          sqlite3VdbeChangeEncoding(&utf8, SQLITE_UTF8);
+          sqlite3XPrintf(&out, "'%.*q'", utf8.n, utf8.z);
+          sqlite3VdbeMemRelease(&utf8);
+        }else
+#endif
+        {
+          sqlite3XPrintf(&out, "'%.*q'", pVar->n, pVar->z);
+        }
+      }else if( pVar->flags & MEM_Zero ){
+        sqlite3XPrintf(&out, "zeroblob(%d)", pVar->u.nZero);
+      }else{
+        assert( pVar->flags & MEM_Blob );
+        sqlite3StrAccumAppend(&out, "x'", 2);
+        for(i=0; i<pVar->n; i++){
+          sqlite3XPrintf(&out, "%02x", pVar->z[i]&0xff);
+        }
+        sqlite3StrAccumAppend(&out, "'", 1);
+      }
+    }
+  }
+  return sqlite3StrAccumFinish(&out);
+}
+
+#endif /* #ifndef SQLITE_OMIT_TRACE */
+
+/*****************************************************************************
+** The following code implements the data-structure explaining logic
+** for the Vdbe.
+*/
+
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
+
+/*
+** Allocate a new Explain object
+*/
+SQLITE_PRIVATE void sqlite3ExplainBegin(Vdbe *pVdbe){
+  if( pVdbe ){
+    Explain *p;
+    sqlite3BeginBenignMalloc();
+    p = (Explain *)sqlite3MallocZero( sizeof(Explain) );
+    if( p ){
+      p->pVdbe = pVdbe;
+      sqlite3_free(pVdbe->pExplain);
+      pVdbe->pExplain = p;
+      sqlite3StrAccumInit(&p->str, p->zBase, sizeof(p->zBase),
+                          SQLITE_MAX_LENGTH);
+      p->str.useMalloc = 2;
+    }else{
+      sqlite3EndBenignMalloc();
+    }
+  }
+}
+
+/*
+** Return true if the Explain ends with a new-line.
+*/
+static int endsWithNL(Explain *p){
+  return p && p->str.zText && p->str.nChar
+           && p->str.zText[p->str.nChar-1]=='\n';
+}
+    
+/*
+** Append text to the indentation
+*/
+SQLITE_PRIVATE void sqlite3ExplainPrintf(Vdbe *pVdbe, const char *zFormat, ...){
+  Explain *p;
+  if( pVdbe && (p = pVdbe->pExplain)!=0 ){
+    va_list ap;
+    if( p->nIndent && endsWithNL(p) ){
+      int n = p->nIndent;
+      if( n>ArraySize(p->aIndent) ) n = ArraySize(p->aIndent);
+      sqlite3AppendSpace(&p->str, p->aIndent[n-1]);
+    }   
+    va_start(ap, zFormat);
+    sqlite3VXPrintf(&p->str, 1, zFormat, ap);
+    va_end(ap);
+  }
+}
+
+/*
+** Append a '\n' if there is not already one.
+*/
+SQLITE_PRIVATE void sqlite3ExplainNL(Vdbe *pVdbe){
+  Explain *p;
+  if( pVdbe && (p = pVdbe->pExplain)!=0 && !endsWithNL(p) ){
+    sqlite3StrAccumAppend(&p->str, "\n", 1);
+  }
+}
+
+/*
+** Push a new indentation level.  Subsequent lines will be indented
+** so that they begin at the current cursor position.
+*/
+SQLITE_PRIVATE void sqlite3ExplainPush(Vdbe *pVdbe){
+  Explain *p;
+  if( pVdbe && (p = pVdbe->pExplain)!=0 ){
+    if( p->str.zText && p->nIndent<ArraySize(p->aIndent) ){
+      const char *z = p->str.zText;
+      int i = p->str.nChar-1;
+      int x;
+      while( i>=0 && z[i]!='\n' ){ i--; }
+      x = (p->str.nChar - 1) - i;
+      if( p->nIndent && x<p->aIndent[p->nIndent-1] ){
+        x = p->aIndent[p->nIndent-1];
+      }
+      p->aIndent[p->nIndent] = x;
+    }
+    p->nIndent++;
+  }
+}
+
+/*
+** Pop the indentation stack by one level.
+*/
+SQLITE_PRIVATE void sqlite3ExplainPop(Vdbe *p){
+  if( p && p->pExplain ) p->pExplain->nIndent--;
+}
+
+/*
+** Free the indentation structure
+*/
+SQLITE_PRIVATE void sqlite3ExplainFinish(Vdbe *pVdbe){
+  if( pVdbe && pVdbe->pExplain ){
+    sqlite3_free(pVdbe->zExplain);
+    sqlite3ExplainNL(pVdbe);
+    pVdbe->zExplain = sqlite3StrAccumFinish(&pVdbe->pExplain->str);
+    sqlite3_free(pVdbe->pExplain);
+    pVdbe->pExplain = 0;
+    sqlite3EndBenignMalloc();
+  }
+}
+
+/*
+** Return the explanation of a virtual machine.
+*/
+SQLITE_PRIVATE const char *sqlite3VdbeExplanation(Vdbe *pVdbe){
+  return (pVdbe && pVdbe->zExplain) ? pVdbe->zExplain : 0;
+}
+#endif /* defined(SQLITE_DEBUG) */
+
+/************** End of vdbetrace.c *******************************************/
 /************** Begin file vdbe.c ********************************************/
 /*
 ** 2001 September 15
@@ -48723,10 +62986,19 @@ SQLITE_API int sqlite3_stmt_status(sqlite3_stmt *pStmt, int op, int resetFlag){
 ** of the code in this file is, therefore, important.  See other comments
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
+/*
+** Invoke this macro on memory cells just prior to changing the
+** value of the cell.  This macro verifies that shallow copies are
+** not misused.
+*/
+#ifdef SQLITE_DEBUG
+# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
+#else
+# define memAboutToChange(P,M)
+#endif
+
 /*
 ** The following global variable is incremented every time a cursor
 ** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
@@ -48740,8 +63012,8 @@ SQLITE_API int sqlite3_search_count = 0;
 
 /*
 ** When this global variable is positive, it gets decremented once before
-** each instruction in the VDBE.  When reaches zero, the u1.isInterrupted
-** field of the sqlite3 structure is set in order to simulate and interrupt.
+** each instruction in the VDBE.  When it reaches zero, the u1.isInterrupted
+** field of the sqlite3 structure is set in order to simulate an interrupt.
 **
 ** This facility is used for testing purposes only.  It does not function
 ** in an ordinary build.
@@ -48777,6 +63049,17 @@ static void updateMaxBlobsize(Mem *p){
 }
 #endif
 
+/*
+** The next global variable is incremented each type the OP_Found opcode
+** is executed. This is used to test whether or not the foreign key
+** operation implemented using OP_FkIsZero is working. This variable
+** has no function other than to help verify the correct operation of the
+** library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_found_count = 0;
+#endif
+
 /*
 ** Test a register to see if it exceeds the current maximum blob size.
 ** If it does, record the new maximum blob size.
@@ -48810,21 +63093,20 @@ static void updateMaxBlobsize(Mem *p){
    if( ((P)->flags&MEM_Ephem)!=0 \
        && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}
 
-/*
-** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
-** P if required.
-*/
-#define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
+/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
+#ifdef SQLITE_OMIT_MERGE_SORT
+# define isSorter(x) 0
+#else
+# define isSorter(x) ((x)->pSorter!=0)
+#endif
 
 /*
 ** Argument pMem points at a register that will be passed to a
 ** user-defined function or returned to the user as the result of a query.
-** The second argument, 'db_enc' is the text encoding used by the vdbe for
-** register variables.  This routine sets the pMem->enc and pMem->type
-** variables used by the sqlite3_value_*() routines.
+** This routine sets the pMem->type variable used by the sqlite3_value_*() 
+** routines.
 */
-#define storeTypeInfo(A,B) _storeTypeInfo(A)
-static void _storeTypeInfo(Mem *pMem){
+SQLITE_PRIVATE void sqlite3VdbeMemStoreType(Mem *pMem){
   int flags = pMem->flags;
   if( flags & MEM_Null ){
     pMem->type = SQLITE_NULL;
@@ -48842,23 +63124,6 @@ static void _storeTypeInfo(Mem *pMem){
   }
 }
 
-/*
-** Properties of opcodes.  The OPFLG_INITIALIZER macro is
-** created by mkopcodeh.awk during compilation.  Data is obtained
-** from the comments following the "case OP_xxxx:" statements in
-** this file.  
-*/
-static const unsigned char opcodeProperty[] = OPFLG_INITIALIZER;
-
-/*
-** Return true if an opcode has any of the OPFLG_xxx properties
-** specified by mask.
-*/
-SQLITE_PRIVATE int sqlite3VdbeOpcodeHasProperty(int opcode, int mask){
-  assert( opcode>0 && opcode<(int)sizeof(opcodeProperty) );
-  return (opcodeProperty[opcode]&mask)!=0;
-}
-
 /*
 ** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
 ** if we run out of memory.
@@ -48866,9 +63131,9 @@ SQLITE_PRIVATE int sqlite3VdbeOpcodeHasProperty(int opcode, int mask){
 static VdbeCursor *allocateCursor(
   Vdbe *p,              /* The virtual machine */
   int iCur,             /* Index of the new VdbeCursor */
-  Op *pOp,              /* */
-  int iDb,              /* When database the cursor belongs to, or -1 */
-  int isBtreeCursor     /* */
+  int nField,           /* Number of fields in the table or index */
+  int iDb,              /* Database the cursor belongs to, or -1 */
+  int isBtreeCursor     /* True for B-Tree.  False for pseudo-table or vtab */
 ){
   /* Find the memory cell that will be used to store the blob of memory
   ** required for this VdbeCursor structure. It is convenient to use a 
@@ -48892,17 +63157,8 @@ static VdbeCursor *allocateCursor(
 
   int nByte;
   VdbeCursor *pCx = 0;
-  /* If the opcode of pOp is OP_SetNumColumns, then pOp->p2 contains
-  ** the number of fields in the records contained in the table or
-  ** index being opened. Use this to reserve space for the 
-  ** VdbeCursor.aType[] array.
-  */
-  int nField = 0;
-  if( pOp->opcode==OP_SetNumColumns || pOp->opcode==OP_OpenEphemeral ){
-    nField = pOp->p2;
-  }
   nByte = 
-      sizeof(VdbeCursor) + 
+      ROUND8(sizeof(VdbeCursor)) + 
       (isBtreeCursor?sqlite3BtreeCursorSize():0) + 
       2*nField*sizeof(u32);
 
@@ -48913,15 +63169,16 @@ static VdbeCursor *allocateCursor(
   }
   if( SQLITE_OK==sqlite3VdbeMemGrow(pMem, nByte, 0) ){
     p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->z;
-    memset(pMem->z, 0, nByte);
+    memset(pCx, 0, sizeof(VdbeCursor));
     pCx->iDb = iDb;
     pCx->nField = nField;
     if( nField ){
-      pCx->aType = (u32 *)&pMem->z[sizeof(VdbeCursor)];
+      pCx->aType = (u32 *)&pMem->z[ROUND8(sizeof(VdbeCursor))];
     }
     if( isBtreeCursor ){
       pCx->pCursor = (BtCursor*)
-          &pMem->z[sizeof(VdbeCursor)+2*nField*sizeof(u32)];
+          &pMem->z[ROUND8(sizeof(VdbeCursor))+2*nField*sizeof(u32)];
+      sqlite3BtreeCursorZero(pCx->pCursor);
     }
   }
   return pCx;
@@ -48935,18 +63192,17 @@ static VdbeCursor *allocateCursor(
 */
 static void applyNumericAffinity(Mem *pRec){
   if( (pRec->flags & (MEM_Real|MEM_Int))==0 ){
-    int realnum;
-    sqlite3VdbeMemNulTerminate(pRec);
-    if( (pRec->flags&MEM_Str)
-         && sqlite3IsNumber(pRec->z, &realnum, pRec->enc) ){
-      i64 value;
-      sqlite3VdbeChangeEncoding(pRec, SQLITE_UTF8);
-      if( !realnum && sqlite3Atoi64(pRec->z, &value) ){
-        pRec->u.i = value;
-        MemSetTypeFlag(pRec, MEM_Int);
-      }else{
-        sqlite3VdbeMemRealify(pRec);
-      }
+    double rValue;
+    i64 iValue;
+    u8 enc = pRec->enc;
+    if( (pRec->flags&MEM_Str)==0 ) return;
+    if( sqlite3AtoF(pRec->z, &rValue, pRec->n, enc)==0 ) return;
+    if( 0==sqlite3Atoi64(pRec->z, &iValue, pRec->n, enc) ){
+      pRec->u.i = iValue;
+      pRec->flags |= MEM_Int;
+    }else{
+      pRec->r = rValue;
+      pRec->flags |= MEM_Real;
     }
   }
 }
@@ -48998,13 +63254,13 @@ static void applyAffinity(
 ** into a numeric representation.  Use either INTEGER or REAL whichever
 ** is appropriate.  But only do the conversion if it is possible without
 ** loss of information and return the revised type of the argument.
-**
-** This is an EXPERIMENTAL api and is subject to change or removal.
 */
 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value *pVal){
   Mem *pMem = (Mem*)pVal;
-  applyNumericAffinity(pMem);
-  storeTypeInfo(pMem, 0);
+  if( pMem->type==SQLITE_TEXT ){
+    applyNumericAffinity(pMem);
+    sqlite3VdbeMemStoreType(pMem);
+  }
   return pMem->type;
 }
 
@@ -49114,8 +63370,12 @@ static void memTracePrint(FILE *out, Mem *p){
     fprintf(out, " si:%lld", p->u.i);
   }else if( p->flags & MEM_Int ){
     fprintf(out, " i:%lld", p->u.i);
+#ifndef SQLITE_OMIT_FLOATING_POINT
   }else if( p->flags & MEM_Real ){
     fprintf(out, " r:%g", p->r);
+#endif
+  }else if( p->flags & MEM_RowSet ){
+    fprintf(out, " (rowset)");
   }else{
     char zBuf[200];
     sqlite3VdbeMemPrettyPrint(p, zBuf);
@@ -49159,8 +63419,6 @@ static void registerTrace(FILE *out, int iReg, Mem *p){
 **
 ** This file contains inline asm code for retrieving "high-performance"
 ** counters for x86 class CPUs.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _HWTIME_H_
 #define _HWTIME_H_
@@ -49245,28 +63503,12 @@ SQLITE_PRIVATE   sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }
 **
 ** This macro added to every instruction that does a jump in order to
 ** implement a loop.  This test used to be on every single instruction,
-** but that meant we more testing that we needed.  By only testing the
+** but that meant we more testing than we needed.  By only testing the
 ** flag on jump instructions, we get a (small) speed improvement.
 */
 #define CHECK_FOR_INTERRUPT \
    if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
 
-#ifdef SQLITE_DEBUG
-static int fileExists(sqlite3 *db, const char *zFile){
-  int res = 0;
-  int rc = SQLITE_OK;
-#ifdef SQLITE_TEST
-  /* If we are currently testing IO errors, then do not call OsAccess() to
-  ** test for the presence of zFile. This is because any IO error that
-  ** occurs here will not be reported, causing the test to fail.
-  */
-  extern int sqlite3_io_error_pending;
-  if( sqlite3_io_error_pending<=0 )
-#endif
-    rc = sqlite3OsAccess(db->pVfs, zFile, SQLITE_ACCESS_EXISTS, &res);
-  return (res && rc==SQLITE_OK);
-}
-#endif
 
 #ifndef NDEBUG
 /*
@@ -49288,6 +63530,20 @@ static int checkSavepointCount(sqlite3 *db){
 }
 #endif
 
+/*
+** Transfer error message text from an sqlite3_vtab.zErrMsg (text stored
+** in memory obtained from sqlite3_malloc) into a Vdbe.zErrMsg (text stored
+** in memory obtained from sqlite3DbMalloc).
+*/
+static void importVtabErrMsg(Vdbe *p, sqlite3_vtab *pVtab){
+  sqlite3 *db = p->db;
+  sqlite3DbFree(db, p->zErrMsg);
+  p->zErrMsg = sqlite3DbStrDup(db, pVtab->zErrMsg);
+  sqlite3_free(pVtab->zErrMsg);
+  pVtab->zErrMsg = 0;
+}
+
+
 /*
 ** Execute as much of a VDBE program as we can then return.
 **
@@ -49322,30 +63578,455 @@ static int checkSavepointCount(sqlite3 *db){
 SQLITE_PRIVATE int sqlite3VdbeExec(
   Vdbe *p                    /* The VDBE */
 ){
-  int pc;                    /* The program counter */
+  int pc=0;                  /* The program counter */
+  Op *aOp = p->aOp;          /* Copy of p->aOp */
   Op *pOp;                   /* Current operation */
   int rc = SQLITE_OK;        /* Value to return */
   sqlite3 *db = p->db;       /* The database */
+  u8 resetSchemaOnFault = 0; /* Reset schema after an error if positive */
   u8 encoding = ENC(db);     /* The database encoding */
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  int checkProgress;         /* True if progress callbacks are enabled */
+  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
+#endif
+  Mem *aMem = p->aMem;       /* Copy of p->aMem */
   Mem *pIn1 = 0;             /* 1st input operand */
   Mem *pIn2 = 0;             /* 2nd input operand */
   Mem *pIn3 = 0;             /* 3rd input operand */
   Mem *pOut = 0;             /* Output operand */
-  u8 opProperty;
   int iCompare = 0;          /* Result of last OP_Compare operation */
-  int *aPermute = 0;         /* Permuation of columns for OP_Compare */
+  int *aPermute = 0;         /* Permutation of columns for OP_Compare */
+  i64 lastRowid = db->lastRowid;  /* Saved value of the last insert ROWID */
 #ifdef VDBE_PROFILE
   u64 start;                 /* CPU clock count at start of opcode */
   int origPc;                /* Program counter at start of opcode */
 #endif
-#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
-  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
-#endif
-  UnpackedRecord aTempRec[16]; /* Space to hold a transient UnpackedRecord */
+  /********************************************************************
+  ** Automatically generated code
+  **
+  ** The following union is automatically generated by the
+  ** vdbe-compress.tcl script.  The purpose of this union is to
+  ** reduce the amount of stack space required by this function.
+  ** See comments in the vdbe-compress.tcl script for details.
+  */
+  union vdbeExecUnion {
+    struct OP_Yield_stack_vars {
+      int pcDest;
+    } aa;
+    struct OP_Null_stack_vars {
+      int cnt;
+    } ab;
+    struct OP_Variable_stack_vars {
+      Mem *pVar;       /* Value being transferred */
+    } ac;
+    struct OP_Move_stack_vars {
+      char *zMalloc;   /* Holding variable for allocated memory */
+      int n;           /* Number of registers left to copy */
+      int p1;          /* Register to copy from */
+      int p2;          /* Register to copy to */
+    } ad;
+    struct OP_ResultRow_stack_vars {
+      Mem *pMem;
+      int i;
+    } ae;
+    struct OP_Concat_stack_vars {
+      i64 nByte;
+    } af;
+    struct OP_Remainder_stack_vars {
+      int flags;      /* Combined MEM_* flags from both inputs */
+      i64 iA;         /* Integer value of left operand */
+      i64 iB;         /* Integer value of right operand */
+      double rA;      /* Real value of left operand */
+      double rB;      /* Real value of right operand */
+    } ag;
+    struct OP_Function_stack_vars {
+      int i;
+      Mem *pArg;
+      sqlite3_context ctx;
+      sqlite3_value **apVal;
+      int n;
+    } ah;
+    struct OP_ShiftRight_stack_vars {
+      i64 iA;
+      u64 uA;
+      i64 iB;
+      u8 op;
+    } ai;
+    struct OP_Ge_stack_vars {
+      int res;            /* Result of the comparison of pIn1 against pIn3 */
+      char affinity;      /* Affinity to use for comparison */
+      u16 flags1;         /* Copy of initial value of pIn1->flags */
+      u16 flags3;         /* Copy of initial value of pIn3->flags */
+    } aj;
+    struct OP_Compare_stack_vars {
+      int n;
+      int i;
+      int p1;
+      int p2;
+      const KeyInfo *pKeyInfo;
+      int idx;
+      CollSeq *pColl;    /* Collating sequence to use on this term */
+      int bRev;          /* True for DESCENDING sort order */
+    } ak;
+    struct OP_Or_stack_vars {
+      int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+      int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+    } al;
+    struct OP_IfNot_stack_vars {
+      int c;
+    } am;
+    struct OP_Column_stack_vars {
+      u32 payloadSize;   /* Number of bytes in the record */
+      i64 payloadSize64; /* Number of bytes in the record */
+      int p1;            /* P1 value of the opcode */
+      int p2;            /* column number to retrieve */
+      VdbeCursor *pC;    /* The VDBE cursor */
+      char *zRec;        /* Pointer to complete record-data */
+      BtCursor *pCrsr;   /* The BTree cursor */
+      u32 *aType;        /* aType[i] holds the numeric type of the i-th column */
+      u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
+      int nField;        /* number of fields in the record */
+      int len;           /* The length of the serialized data for the column */
+      int i;             /* Loop counter */
+      char *zData;       /* Part of the record being decoded */
+      Mem *pDest;        /* Where to write the extracted value */
+      Mem sMem;          /* For storing the record being decoded */
+      u8 *zIdx;          /* Index into header */
+      u8 *zEndHdr;       /* Pointer to first byte after the header */
+      u32 offset;        /* Offset into the data */
+      u32 szField;       /* Number of bytes in the content of a field */
+      int szHdr;         /* Size of the header size field at start of record */
+      int avail;         /* Number of bytes of available data */
+      u32 t;             /* A type code from the record header */
+      Mem *pReg;         /* PseudoTable input register */
+    } an;
+    struct OP_Affinity_stack_vars {
+      const char *zAffinity;   /* The affinity to be applied */
+      char cAff;               /* A single character of affinity */
+    } ao;
+    struct OP_MakeRecord_stack_vars {
+      u8 *zNewRecord;        /* A buffer to hold the data for the new record */
+      Mem *pRec;             /* The new record */
+      u64 nData;             /* Number of bytes of data space */
+      int nHdr;              /* Number of bytes of header space */
+      i64 nByte;             /* Data space required for this record */
+      int nZero;             /* Number of zero bytes at the end of the record */
+      int nVarint;           /* Number of bytes in a varint */
+      u32 serial_type;       /* Type field */
+      Mem *pData0;           /* First field to be combined into the record */
+      Mem *pLast;            /* Last field of the record */
+      int nField;            /* Number of fields in the record */
+      char *zAffinity;       /* The affinity string for the record */
+      int file_format;       /* File format to use for encoding */
+      int i;                 /* Space used in zNewRecord[] */
+      int len;               /* Length of a field */
+    } ap;
+    struct OP_Count_stack_vars {
+      i64 nEntry;
+      BtCursor *pCrsr;
+    } aq;
+    struct OP_Savepoint_stack_vars {
+      int p1;                         /* Value of P1 operand */
+      char *zName;                    /* Name of savepoint */
+      int nName;
+      Savepoint *pNew;
+      Savepoint *pSavepoint;
+      Savepoint *pTmp;
+      int iSavepoint;
+      int ii;
+    } ar;
+    struct OP_AutoCommit_stack_vars {
+      int desiredAutoCommit;
+      int iRollback;
+      int turnOnAC;
+    } as;
+    struct OP_Transaction_stack_vars {
+      Btree *pBt;
+    } at;
+    struct OP_ReadCookie_stack_vars {
+      int iMeta;
+      int iDb;
+      int iCookie;
+    } au;
+    struct OP_SetCookie_stack_vars {
+      Db *pDb;
+    } av;
+    struct OP_VerifyCookie_stack_vars {
+      int iMeta;
+      int iGen;
+      Btree *pBt;
+    } aw;
+    struct OP_OpenWrite_stack_vars {
+      int nField;
+      KeyInfo *pKeyInfo;
+      int p2;
+      int iDb;
+      int wrFlag;
+      Btree *pX;
+      VdbeCursor *pCur;
+      Db *pDb;
+    } ax;
+    struct OP_OpenEphemeral_stack_vars {
+      VdbeCursor *pCx;
+    } ay;
+    struct OP_SorterOpen_stack_vars {
+      VdbeCursor *pCx;
+    } az;
+    struct OP_OpenPseudo_stack_vars {
+      VdbeCursor *pCx;
+    } ba;
+    struct OP_SeekGt_stack_vars {
+      int res;
+      int oc;
+      VdbeCursor *pC;
+      UnpackedRecord r;
+      int nField;
+      i64 iKey;      /* The rowid we are to seek to */
+    } bb;
+    struct OP_Seek_stack_vars {
+      VdbeCursor *pC;
+    } bc;
+    struct OP_Found_stack_vars {
+      int alreadyExists;
+      VdbeCursor *pC;
+      int res;
+      char *pFree;
+      UnpackedRecord *pIdxKey;
+      UnpackedRecord r;
+      char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*3 + 7];
+    } bd;
+    struct OP_IsUnique_stack_vars {
+      u16 ii;
+      VdbeCursor *pCx;
+      BtCursor *pCrsr;
+      u16 nField;
+      Mem *aMx;
+      UnpackedRecord r;                  /* B-Tree index search key */
+      i64 R;                             /* Rowid stored in register P3 */
+    } be;
+    struct OP_NotExists_stack_vars {
+      VdbeCursor *pC;
+      BtCursor *pCrsr;
+      int res;
+      u64 iKey;
+    } bf;
+    struct OP_NewRowid_stack_vars {
+      i64 v;                 /* The new rowid */
+      VdbeCursor *pC;        /* Cursor of table to get the new rowid */
+      int res;               /* Result of an sqlite3BtreeLast() */
+      int cnt;               /* Counter to limit the number of searches */
+      Mem *pMem;             /* Register holding largest rowid for AUTOINCREMENT */
+      VdbeFrame *pFrame;     /* Root frame of VDBE */
+    } bg;
+    struct OP_InsertInt_stack_vars {
+      Mem *pData;       /* MEM cell holding data for the record to be inserted */
+      Mem *pKey;        /* MEM cell holding key  for the record */
+      i64 iKey;         /* The integer ROWID or key for the record to be inserted */
+      VdbeCursor *pC;   /* Cursor to table into which insert is written */
+      int nZero;        /* Number of zero-bytes to append */
+      int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
+      const char *zDb;  /* database name - used by the update hook */
+      const char *zTbl; /* Table name - used by the opdate hook */
+      int op;           /* Opcode for update hook: SQLITE_UPDATE or SQLITE_INSERT */
+    } bh;
+    struct OP_Delete_stack_vars {
+      i64 iKey;
+      VdbeCursor *pC;
+    } bi;
+    struct OP_SorterCompare_stack_vars {
+      VdbeCursor *pC;
+      int res;
+    } bj;
+    struct OP_SorterData_stack_vars {
+      VdbeCursor *pC;
+    } bk;
+    struct OP_RowData_stack_vars {
+      VdbeCursor *pC;
+      BtCursor *pCrsr;
+      u32 n;
+      i64 n64;
+    } bl;
+    struct OP_Rowid_stack_vars {
+      VdbeCursor *pC;
+      i64 v;
+      sqlite3_vtab *pVtab;
+      const sqlite3_module *pModule;
+    } bm;
+    struct OP_NullRow_stack_vars {
+      VdbeCursor *pC;
+    } bn;
+    struct OP_Last_stack_vars {
+      VdbeCursor *pC;
+      BtCursor *pCrsr;
+      int res;
+    } bo;
+    struct OP_Rewind_stack_vars {
+      VdbeCursor *pC;
+      BtCursor *pCrsr;
+      int res;
+    } bp;
+    struct OP_Next_stack_vars {
+      VdbeCursor *pC;
+      int res;
+    } bq;
+    struct OP_IdxInsert_stack_vars {
+      VdbeCursor *pC;
+      BtCursor *pCrsr;
+      int nKey;
+      const char *zKey;
+    } br;
+    struct OP_IdxDelete_stack_vars {
+      VdbeCursor *pC;
+      BtCursor *pCrsr;
+      int res;
+      UnpackedRecord r;
+    } bs;
+    struct OP_IdxRowid_stack_vars {
+      BtCursor *pCrsr;
+      VdbeCursor *pC;
+      i64 rowid;
+    } bt;
+    struct OP_IdxGE_stack_vars {
+      VdbeCursor *pC;
+      int res;
+      UnpackedRecord r;
+    } bu;
+    struct OP_Destroy_stack_vars {
+      int iMoved;
+      int iCnt;
+      Vdbe *pVdbe;
+      int iDb;
+    } bv;
+    struct OP_Clear_stack_vars {
+      int nChange;
+    } bw;
+    struct OP_CreateTable_stack_vars {
+      int pgno;
+      int flags;
+      Db *pDb;
+    } bx;
+    struct OP_ParseSchema_stack_vars {
+      int iDb;
+      const char *zMaster;
+      char *zSql;
+      InitData initData;
+    } by;
+    struct OP_IntegrityCk_stack_vars {
+      int nRoot;      /* Number of tables to check.  (Number of root pages.) */
+      int *aRoot;     /* Array of rootpage numbers for tables to be checked */
+      int j;          /* Loop counter */
+      int nErr;       /* Number of errors reported */
+      char *z;        /* Text of the error report */
+      Mem *pnErr;     /* Register keeping track of errors remaining */
+    } bz;
+    struct OP_RowSetRead_stack_vars {
+      i64 val;
+    } ca;
+    struct OP_RowSetTest_stack_vars {
+      int iSet;
+      int exists;
+    } cb;
+    struct OP_Program_stack_vars {
+      int nMem;               /* Number of memory registers for sub-program */
+      int nByte;              /* Bytes of runtime space required for sub-program */
+      Mem *pRt;               /* Register to allocate runtime space */
+      Mem *pMem;              /* Used to iterate through memory cells */
+      Mem *pEnd;              /* Last memory cell in new array */
+      VdbeFrame *pFrame;      /* New vdbe frame to execute in */
+      SubProgram *pProgram;   /* Sub-program to execute */
+      void *t;                /* Token identifying trigger */
+    } cc;
+    struct OP_Param_stack_vars {
+      VdbeFrame *pFrame;
+      Mem *pIn;
+    } cd;
+    struct OP_MemMax_stack_vars {
+      Mem *pIn1;
+      VdbeFrame *pFrame;
+    } ce;
+    struct OP_AggStep_stack_vars {
+      int n;
+      int i;
+      Mem *pMem;
+      Mem *pRec;
+      sqlite3_context ctx;
+      sqlite3_value **apVal;
+    } cf;
+    struct OP_AggFinal_stack_vars {
+      Mem *pMem;
+    } cg;
+    struct OP_Checkpoint_stack_vars {
+      int i;                          /* Loop counter */
+      int aRes[3];                    /* Results */
+      Mem *pMem;                      /* Write results here */
+    } ch;
+    struct OP_JournalMode_stack_vars {
+      Btree *pBt;                     /* Btree to change journal mode of */
+      Pager *pPager;                  /* Pager associated with pBt */
+      int eNew;                       /* New journal mode */
+      int eOld;                       /* The old journal mode */
+      const char *zFilename;          /* Name of database file for pPager */
+    } ci;
+    struct OP_IncrVacuum_stack_vars {
+      Btree *pBt;
+    } cj;
+    struct OP_VBegin_stack_vars {
+      VTable *pVTab;
+    } ck;
+    struct OP_VOpen_stack_vars {
+      VdbeCursor *pCur;
+      sqlite3_vtab_cursor *pVtabCursor;
+      sqlite3_vtab *pVtab;
+      sqlite3_module *pModule;
+    } cl;
+    struct OP_VFilter_stack_vars {
+      int nArg;
+      int iQuery;
+      const sqlite3_module *pModule;
+      Mem *pQuery;
+      Mem *pArgc;
+      sqlite3_vtab_cursor *pVtabCursor;
+      sqlite3_vtab *pVtab;
+      VdbeCursor *pCur;
+      int res;
+      int i;
+      Mem **apArg;
+    } cm;
+    struct OP_VColumn_stack_vars {
+      sqlite3_vtab *pVtab;
+      const sqlite3_module *pModule;
+      Mem *pDest;
+      sqlite3_context sContext;
+    } cn;
+    struct OP_VNext_stack_vars {
+      sqlite3_vtab *pVtab;
+      const sqlite3_module *pModule;
+      int res;
+      VdbeCursor *pCur;
+    } co;
+    struct OP_VRename_stack_vars {
+      sqlite3_vtab *pVtab;
+      Mem *pName;
+    } cp;
+    struct OP_VUpdate_stack_vars {
+      sqlite3_vtab *pVtab;
+      sqlite3_module *pModule;
+      int nArg;
+      int i;
+      sqlite_int64 rowid;
+      Mem **apArg;
+      Mem *pX;
+    } cq;
+    struct OP_Trace_stack_vars {
+      char *zTrace;
+      char *z;
+    } cr;
+  } u;
+  /* End automatically generated code
+  ********************************************************************/
 
   assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
-  assert( db->magic==SQLITE_MAGIC_BUSY );
-  sqlite3BtreeMutexArrayEnter(&p->aMutex);
+  sqlite3VdbeEnter(p);
   if( p->rc==SQLITE_NOMEM ){
     /* This happens if a malloc() inside a call to sqlite3_column_text() or
     ** sqlite3_column_text16() failed.  */
@@ -49358,21 +64039,19 @@ SQLITE_PRIVATE int sqlite3VdbeExec(
   db->busyHandler.nBusy = 0;
   CHECK_FOR_INTERRUPT;
   sqlite3VdbeIOTraceSql(p);
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  checkProgress = db->xProgress!=0;
+#endif
 #ifdef SQLITE_DEBUG
   sqlite3BeginBenignMalloc();
-  if( p->pc==0 
-   && ((p->db->flags & SQLITE_VdbeListing) || fileExists(db, "vdbe_explain"))
-  ){
+  if( p->pc==0  && (p->db->flags & SQLITE_VdbeListing)!=0 ){
     int i;
     printf("VDBE Program Listing:\n");
     sqlite3VdbePrintSql(p);
     for(i=0; i<p->nOp; i++){
-      sqlite3VdbePrintOp(stdout, i, &p->aOp[i]);
+      sqlite3VdbePrintOp(stdout, i, &aOp[i]);
     }
   }
-  if( fileExists(db, "vdbe_trace") ){
-    p->trace = stdout;
-  }
   sqlite3EndBenignMalloc();
 #endif
   for(pc=p->pc; rc==SQLITE_OK; pc++){
@@ -49382,7 +64061,7 @@ SQLITE_PRIVATE int sqlite3VdbeExec(
     origPc = pc;
     start = sqlite3Hwtime();
 #endif
-    pOp = &p->aOp[pc];
+    pOp = &aOp[pc];
 
     /* Only allow tracing if SQLITE_DEBUG is defined.
     */
@@ -49394,13 +64073,6 @@ SQLITE_PRIVATE int sqlite3VdbeExec(
       }
       sqlite3VdbePrintOp(p->trace, pc, pOp);
     }
-    if( p->trace==0 && pc==0 ){
-      sqlite3BeginBenignMalloc();
-      if( fileExists(db, "vdbe_sqltrace") ){
-        sqlite3VdbePrintSql(p);
-      }
-      sqlite3EndBenignMalloc();
-    }
 #endif
       
 
@@ -49423,12 +64095,10 @@ SQLITE_PRIVATE int sqlite3VdbeExec(
     ** If the progress callback returns non-zero, exit the virtual machine with
     ** a return code SQLITE_ABORT.
     */
-    if( db->xProgress ){
+    if( checkProgress ){
       if( db->nProgressOps==nProgressOps ){
         int prc;
-        if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-        prc =db->xProgress(db->pProgressArg);
-        if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+        prc = db->xProgress(db->pProgressArg);
         if( prc!=0 ){
           rc = SQLITE_INTERRUPT;
           goto vdbe_error_halt;
@@ -49439,64 +64109,53 @@ SQLITE_PRIVATE int sqlite3VdbeExec(
     }
 #endif
 
-    /* Do common setup processing for any opcode that is marked
-    ** with the "out2-prerelease" tag.  Such opcodes have a single
-    ** output which is specified by the P2 parameter.  The P2 register
-    ** is initialized to a NULL.
+    /* On any opcode with the "out2-prerelease" tag, free any
+    ** external allocations out of mem[p2] and set mem[p2] to be
+    ** an undefined integer.  Opcodes will either fill in the integer
+    ** value or convert mem[p2] to a different type.
     */
-    opProperty = opcodeProperty[pOp->opcode];
-    if( (opProperty & OPFLG_OUT2_PRERELEASE)!=0 ){
+    assert( pOp->opflags==sqlite3OpcodeProperty[pOp->opcode] );
+    if( pOp->opflags & OPFLG_OUT2_PRERELEASE ){
       assert( pOp->p2>0 );
       assert( pOp->p2<=p->nMem );
-      pOut = &p->aMem[pOp->p2];
-      sqlite3VdbeMemReleaseExternal(pOut);
-      pOut->flags = MEM_Null;
-    }else
- 
-    /* Do common setup for opcodes marked with one of the following
-    ** combinations of properties.
-    **
-    **           in1
-    **           in1 in2
-    **           in1 in2 out3
-    **           in1 in3
-    **
-    ** Variables pIn1, pIn2, and pIn3 are made to point to appropriate
-    ** registers for inputs.  Variable pOut points to the output register.
-    */
-    if( (opProperty & OPFLG_IN1)!=0 ){
-      assert( pOp->p1>0 );
-      assert( pOp->p1<=p->nMem );
-      pIn1 = &p->aMem[pOp->p1];
-      REGISTER_TRACE(pOp->p1, pIn1);
-      if( (opProperty & OPFLG_IN2)!=0 ){
-        assert( pOp->p2>0 );
-        assert( pOp->p2<=p->nMem );
-        pIn2 = &p->aMem[pOp->p2];
-        REGISTER_TRACE(pOp->p2, pIn2);
-        if( (opProperty & OPFLG_OUT3)!=0 ){
-          assert( pOp->p3>0 );
-          assert( pOp->p3<=p->nMem );
-          pOut = &p->aMem[pOp->p3];
-        }
-      }else if( (opProperty & OPFLG_IN3)!=0 ){
-        assert( pOp->p3>0 );
-        assert( pOp->p3<=p->nMem );
-        pIn3 = &p->aMem[pOp->p3];
-        REGISTER_TRACE(pOp->p3, pIn3);
-      }
-    }else if( (opProperty & OPFLG_IN2)!=0 ){
-      assert( pOp->p2>0 );
-      assert( pOp->p2<=p->nMem );
-      pIn2 = &p->aMem[pOp->p2];
-      REGISTER_TRACE(pOp->p2, pIn2);
-    }else if( (opProperty & OPFLG_IN3)!=0 ){
-      assert( pOp->p3>0 );
-      assert( pOp->p3<=p->nMem );
-      pIn3 = &p->aMem[pOp->p3];
-      REGISTER_TRACE(pOp->p3, pIn3);
+      pOut = &aMem[pOp->p2];
+      memAboutToChange(p, pOut);
+      VdbeMemRelease(pOut);
+      pOut->flags = MEM_Int;
     }
 
+    /* Sanity checking on other operands */
+#ifdef SQLITE_DEBUG
+    if( (pOp->opflags & OPFLG_IN1)!=0 ){
+      assert( pOp->p1>0 );
+      assert( pOp->p1<=p->nMem );
+      assert( memIsValid(&aMem[pOp->p1]) );
+      REGISTER_TRACE(pOp->p1, &aMem[pOp->p1]);
+    }
+    if( (pOp->opflags & OPFLG_IN2)!=0 ){
+      assert( pOp->p2>0 );
+      assert( pOp->p2<=p->nMem );
+      assert( memIsValid(&aMem[pOp->p2]) );
+      REGISTER_TRACE(pOp->p2, &aMem[pOp->p2]);
+    }
+    if( (pOp->opflags & OPFLG_IN3)!=0 ){
+      assert( pOp->p3>0 );
+      assert( pOp->p3<=p->nMem );
+      assert( memIsValid(&aMem[pOp->p3]) );
+      REGISTER_TRACE(pOp->p3, &aMem[pOp->p3]);
+    }
+    if( (pOp->opflags & OPFLG_OUT2)!=0 ){
+      assert( pOp->p2>0 );
+      assert( pOp->p2<=p->nMem );
+      memAboutToChange(p, &aMem[pOp->p2]);
+    }
+    if( (pOp->opflags & OPFLG_OUT3)!=0 ){
+      assert( pOp->p3>0 );
+      assert( pOp->p3<=p->nMem );
+      memAboutToChange(p, &aMem[pOp->p3]);
+    }
+#endif
+  
     switch( pOp->opcode ){
 
 /*****************************************************************************
@@ -49553,10 +64212,10 @@ case OP_Goto: {             /* jump */
 ** and then jump to address P2.
 */
 case OP_Gosub: {            /* jump */
-  assert( pOp->p1>0 );
-  assert( pOp->p1<=p->nMem );
-  pIn1 = &p->aMem[pOp->p1];
+  assert( pOp->p1>0 && pOp->p1<=p->nMem );
+  pIn1 = &aMem[pOp->p1];
   assert( (pIn1->flags & MEM_Dyn)==0 );
+  memAboutToChange(p, pIn1);
   pIn1->flags = MEM_Int;
   pIn1->u.i = pc;
   REGISTER_TRACE(pOp->p1, pIn1);
@@ -49569,6 +64228,7 @@ case OP_Gosub: {            /* jump */
 ** Jump to the next instruction after the address in register P1.
 */
 case OP_Return: {           /* in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags & MEM_Int );
   pc = (int)pIn1->u.i;
   break;
@@ -49579,16 +64239,30 @@ case OP_Return: {           /* in1 */
 ** Swap the program counter with the value in register P1.
 */
 case OP_Yield: {            /* in1 */
+#if 0  /* local variables moved into u.aa */
   int pcDest;
+#endif /* local variables moved into u.aa */
+  pIn1 = &aMem[pOp->p1];
   assert( (pIn1->flags & MEM_Dyn)==0 );
   pIn1->flags = MEM_Int;
-  pcDest = (int)pIn1->u.i;
+  u.aa.pcDest = (int)pIn1->u.i;
   pIn1->u.i = pc;
   REGISTER_TRACE(pOp->p1, pIn1);
-  pc = pcDest;
+  pc = u.aa.pcDest;
   break;
 }
 
+/* Opcode:  HaltIfNull  P1 P2 P3 P4 *
+**
+** Check the value in register P3.  If it is NULL then Halt using
+** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
+** value in register P3 is not NULL, then this routine is a no-op.
+*/
+case OP_HaltIfNull: {      /* in3 */
+  pIn3 = &aMem[pOp->p3];
+  if( (pIn3->flags & MEM_Null)==0 ) break;
+  /* Fall through into OP_Halt */
+}
 
 /* Opcode:  Halt P1 P2 * P4 *
 **
@@ -49610,17 +64284,46 @@ case OP_Yield: {            /* in1 */
 ** is the same as executing Halt.
 */
 case OP_Halt: {
+  if( pOp->p1==SQLITE_OK && p->pFrame ){
+    /* Halt the sub-program. Return control to the parent frame. */
+    VdbeFrame *pFrame = p->pFrame;
+    p->pFrame = pFrame->pParent;
+    p->nFrame--;
+    sqlite3VdbeSetChanges(db, p->nChange);
+    pc = sqlite3VdbeFrameRestore(pFrame);
+    lastRowid = db->lastRowid;
+    if( pOp->p2==OE_Ignore ){
+      /* Instruction pc is the OP_Program that invoked the sub-program 
+      ** currently being halted. If the p2 instruction of this OP_Halt
+      ** instruction is set to OE_Ignore, then the sub-program is throwing
+      ** an IGNORE exception. In this case jump to the address specified
+      ** as the p2 of the calling OP_Program.  */
+      pc = p->aOp[pc].p2-1;
+    }
+    aOp = p->aOp;
+    aMem = p->aMem;
+    break;
+  }
+
   p->rc = pOp->p1;
+  p->errorAction = (u8)pOp->p2;
   p->pc = pc;
-  p->errorAction = pOp->p2;
   if( pOp->p4.z ){
+    assert( p->rc!=SQLITE_OK );
     sqlite3SetString(&p->zErrMsg, db, "%s", pOp->p4.z);
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(pOp->p1, "abort at %d in [%s]: %s", pc, p->zSql, pOp->p4.z);
+  }else if( p->rc ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(pOp->p1, "constraint failed at %d in [%s]", pc, p->zSql);
   }
   rc = sqlite3VdbeHalt(p);
-  assert( rc==SQLITE_BUSY || rc==SQLITE_OK );
+  assert( rc==SQLITE_BUSY || rc==SQLITE_OK || rc==SQLITE_ERROR );
   if( rc==SQLITE_BUSY ){
     p->rc = rc = SQLITE_BUSY;
   }else{
+    assert( rc==SQLITE_OK || p->rc==SQLITE_CONSTRAINT );
+    assert( rc==SQLITE_OK || db->nDeferredCons>0 );
     rc = p->rc ? SQLITE_ERROR : SQLITE_DONE;
   }
   goto vdbe_return;
@@ -49631,7 +64334,6 @@ case OP_Halt: {
 ** The 32-bit integer value P1 is written into register P2.
 */
 case OP_Integer: {         /* out2-prerelease */
-  pOut->flags = MEM_Int;
   pOut->u.i = pOp->p1;
   break;
 }
@@ -49643,11 +64345,11 @@ case OP_Integer: {         /* out2-prerelease */
 */
 case OP_Int64: {           /* out2-prerelease */
   assert( pOp->p4.pI64!=0 );
-  pOut->flags = MEM_Int;
   pOut->u.i = *pOp->p4.pI64;
   break;
 }
 
+#ifndef SQLITE_OMIT_FLOATING_POINT
 /* Opcode: Real * P2 * P4 *
 **
 ** P4 is a pointer to a 64-bit floating point value.
@@ -49659,6 +64361,7 @@ case OP_Real: {            /* same as TK_FLOAT, out2-prerelease */
   pOut->r = *pOp->p4.pReal;
   break;
 }
+#endif
 
 /* Opcode: String8 * P2 * P4 *
 **
@@ -49672,9 +64375,11 @@ case OP_String8: {         /* same as TK_STRING, out2-prerelease */
 
 #ifndef SQLITE_OMIT_UTF16
   if( encoding!=SQLITE_UTF8 ){
-    sqlite3VdbeMemSetStr(pOut, pOp->p4.z, -1, SQLITE_UTF8, SQLITE_STATIC);
+    rc = sqlite3VdbeMemSetStr(pOut, pOp->p4.z, -1, SQLITE_UTF8, SQLITE_STATIC);
+    if( rc==SQLITE_TOOBIG ) goto too_big;
     if( SQLITE_OK!=sqlite3VdbeChangeEncoding(pOut, encoding) ) goto no_mem;
-    if( SQLITE_OK!=sqlite3VdbeMemMakeWriteable(pOut) ) goto no_mem;
+    assert( pOut->zMalloc==pOut->z );
+    assert( pOut->flags & MEM_Dyn );
     pOut->zMalloc = 0;
     pOut->flags |= MEM_Static;
     pOut->flags &= ~MEM_Dyn;
@@ -49684,11 +64389,6 @@ case OP_String8: {         /* same as TK_STRING, out2-prerelease */
     pOp->p4type = P4_DYNAMIC;
     pOp->p4.z = pOut->z;
     pOp->p1 = pOut->n;
-    if( pOp->p1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
-      goto too_big;
-    }
-    UPDATE_MAX_BLOBSIZE(pOut);
-    break;
   }
 #endif
   if( pOp->p1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
@@ -49711,11 +64411,27 @@ case OP_String: {          /* out2-prerelease */
   break;
 }
 
-/* Opcode: Null * P2 * * *
+/* Opcode: Null * P2 P3 * *
 **
-** Write a NULL into register P2.
+** Write a NULL into registers P2.  If P3 greater than P2, then also write
+** NULL into register P3 and ever register in between P2 and P3.  If P3
+** is less than P2 (typically P3 is zero) then only register P2 is
+** set to NULL
 */
 case OP_Null: {           /* out2-prerelease */
+#if 0  /* local variables moved into u.ab */
+  int cnt;
+#endif /* local variables moved into u.ab */
+  u.ab.cnt = pOp->p3-pOp->p2;
+  assert( pOp->p3<=p->nMem );
+  pOut->flags = MEM_Null;
+  while( u.ab.cnt>0 ){
+    pOut++;
+    memAboutToChange(p, pOut);
+    VdbeMemRelease(pOut);
+    pOut->flags = MEM_Null;
+    u.ab.cnt--;
+  }
   break;
 }
 
@@ -49723,11 +64439,7 @@ case OP_Null: {           /* out2-prerelease */
 /* Opcode: Blob P1 P2 * P4
 **
 ** P4 points to a blob of data P1 bytes long.  Store this
-** blob in register P2. This instruction is not coded directly
-** by the compiler. Instead, the compiler layer specifies
-** an OP_HexBlob opcode, with the hex string representation of
-** the blob as P4. This opcode is transformed to an OP_Blob
-** the first time it is executed.
+** blob in register P2.
 */
 case OP_Blob: {                /* out2-prerelease */
   assert( pOp->p1 <= SQLITE_MAX_LENGTH );
@@ -49737,25 +64449,25 @@ case OP_Blob: {                /* out2-prerelease */
   break;
 }
 
-/* Opcode: Variable P1 P2 * * *
+/* Opcode: Variable P1 P2 * P4 *
 **
-** The value of variable P1 is written into register P2. A variable is
-** an unknown in the original SQL string as handed to sqlite3_compile().
-** Any occurrence of the '?' character in the original SQL is considered
-** a variable.  Variables in the SQL string are number from left to
-** right beginning with 1.  The values of variables are set using the
-** sqlite3_bind() API.
+** Transfer the values of bound parameter P1 into register P2
+**
+** If the parameter is named, then its name appears in P4 and P3==1.
+** The P4 value is used by sqlite3_bind_parameter_name().
 */
-case OP_Variable: {           /* out2-prerelease */
-  int j = pOp->p1 - 1;
-  Mem *pVar;
-  assert( j>=0 && j<p->nVar );
+case OP_Variable: {            /* out2-prerelease */
+#if 0  /* local variables moved into u.ac */
+  Mem *pVar;       /* Value being transferred */
+#endif /* local variables moved into u.ac */
 
-  pVar = &p->aVar[j];
-  if( sqlite3VdbeMemTooBig(pVar) ){
+  assert( pOp->p1>0 && pOp->p1<=p->nVar );
+  assert( pOp->p4.z==0 || pOp->p4.z==p->azVar[pOp->p1-1] );
+  u.ac.pVar = &p->aVar[pOp->p1 - 1];
+  if( sqlite3VdbeMemTooBig(u.ac.pVar) ){
     goto too_big;
   }
-  sqlite3VdbeMemShallowCopy(pOut, &p->aVar[j], MEM_Static);
+  sqlite3VdbeMemShallowCopy(pOut, u.ac.pVar, MEM_Static);
   UPDATE_MAX_BLOBSIZE(pOut);
   break;
 }
@@ -49768,24 +64480,36 @@ case OP_Variable: {           /* out2-prerelease */
 ** P1..P1+P3-1 and P2..P2+P3-1 to overlap.
 */
 case OP_Move: {
-  char *zMalloc;
-  int n = pOp->p3;
-  int p1 = pOp->p1;
-  int p2 = pOp->p2;
-  assert( n>0 );
-  assert( p1>0 );
-  assert( p1+n<p->nMem );
-  pIn1 = &p->aMem[p1];
-  assert( p2>0 );
-  assert( p2+n<p->nMem );
-  pOut = &p->aMem[p2];
-  assert( p1+n<=p2 || p2+n<=p1 );
-  while( n-- ){
-    zMalloc = pOut->zMalloc;
+#if 0  /* local variables moved into u.ad */
+  char *zMalloc;   /* Holding variable for allocated memory */
+  int n;           /* Number of registers left to copy */
+  int p1;          /* Register to copy from */
+  int p2;          /* Register to copy to */
+#endif /* local variables moved into u.ad */
+
+  u.ad.n = pOp->p3;
+  u.ad.p1 = pOp->p1;
+  u.ad.p2 = pOp->p2;
+  assert( u.ad.n>0 && u.ad.p1>0 && u.ad.p2>0 );
+  assert( u.ad.p1+u.ad.n<=u.ad.p2 || u.ad.p2+u.ad.n<=u.ad.p1 );
+
+  pIn1 = &aMem[u.ad.p1];
+  pOut = &aMem[u.ad.p2];
+  while( u.ad.n-- ){
+    assert( pOut<=&aMem[p->nMem] );
+    assert( pIn1<=&aMem[p->nMem] );
+    assert( memIsValid(pIn1) );
+    memAboutToChange(p, pOut);
+    u.ad.zMalloc = pOut->zMalloc;
     pOut->zMalloc = 0;
     sqlite3VdbeMemMove(pOut, pIn1);
-    pIn1->zMalloc = zMalloc;
-    REGISTER_TRACE(p2++, pOut);
+#ifdef SQLITE_DEBUG
+    if( pOut->pScopyFrom>=&aMem[u.ad.p1] && pOut->pScopyFrom<&aMem[u.ad.p1+pOp->p3] ){
+      pOut->pScopyFrom += u.ad.p1 - pOp->p2;
+    }
+#endif
+    pIn1->zMalloc = u.ad.zMalloc;
+    REGISTER_TRACE(u.ad.p2++, pOut);
     pIn1++;
     pOut++;
   }
@@ -49799,10 +64523,9 @@ case OP_Move: {
 ** This instruction makes a deep copy of the value.  A duplicate
 ** is made of any string or blob constant.  See also OP_SCopy.
 */
-case OP_Copy: {             /* in1 */
-  assert( pOp->p2>0 );
-  assert( pOp->p2<=p->nMem );
-  pOut = &p->aMem[pOp->p2];
+case OP_Copy: {             /* in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   assert( pOut!=pIn1 );
   sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
   Deephemeralize(pOut);
@@ -49822,13 +64545,14 @@ case OP_Copy: {             /* in1 */
 ** during the lifetime of the copy.  Use OP_Copy to make a complete
 ** copy.
 */
-case OP_SCopy: {            /* in1 */
-  REGISTER_TRACE(pOp->p1, pIn1);
-  assert( pOp->p2>0 );
-  assert( pOp->p2<=p->nMem );
-  pOut = &p->aMem[pOp->p2];
+case OP_SCopy: {            /* in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   assert( pOut!=pIn1 );
   sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
+#ifdef SQLITE_DEBUG
+  if( pOut->pScopyFrom==0 ) pOut->pScopyFrom = pIn1;
+#endif
   REGISTER_TRACE(pOp->p2, pOut);
   break;
 }
@@ -49842,30 +64566,65 @@ case OP_SCopy: {            /* in1 */
 ** row.
 */
 case OP_ResultRow: {
+#if 0  /* local variables moved into u.ae */
   Mem *pMem;
   int i;
+#endif /* local variables moved into u.ae */
   assert( p->nResColumn==pOp->p2 );
   assert( pOp->p1>0 );
-  assert( pOp->p1+pOp->p2<=p->nMem );
+  assert( pOp->p1+pOp->p2<=p->nMem+1 );
+
+  /* If this statement has violated immediate foreign key constraints, do
+  ** not return the number of rows modified. And do not RELEASE the statement
+  ** transaction. It needs to be rolled back.  */
+  if( SQLITE_OK!=(rc = sqlite3VdbeCheckFk(p, 0)) ){
+    assert( db->flags&SQLITE_CountRows );
+    assert( p->usesStmtJournal );
+    break;
+  }
+
+  /* If the SQLITE_CountRows flag is set in sqlite3.flags mask, then
+  ** DML statements invoke this opcode to return the number of rows
+  ** modified to the user. This is the only way that a VM that
+  ** opens a statement transaction may invoke this opcode.
+  **
+  ** In case this is such a statement, close any statement transaction
+  ** opened by this VM before returning control to the user. This is to
+  ** ensure that statement-transactions are always nested, not overlapping.
+  ** If the open statement-transaction is not closed here, then the user
+  ** may step another VM that opens its own statement transaction. This
+  ** may lead to overlapping statement transactions.
+  **
+  ** The statement transaction is never a top-level transaction.  Hence
+  ** the RELEASE call below can never fail.
+  */
+  assert( p->iStatement==0 || db->flags&SQLITE_CountRows );
+  rc = sqlite3VdbeCloseStatement(p, SAVEPOINT_RELEASE);
+  if( NEVER(rc!=SQLITE_OK) ){
+    break;
+  }
 
   /* Invalidate all ephemeral cursor row caches */
   p->cacheCtr = (p->cacheCtr + 2)|1;
 
   /* Make sure the results of the current row are \000 terminated
   ** and have an assigned type.  The results are de-ephemeralized as
-  ** as side effect.
+  ** a side effect.
   */
-  pMem = p->pResultSet = &p->aMem[pOp->p1];
-  for(i=0; i<pOp->p2; i++){
-    sqlite3VdbeMemNulTerminate(&pMem[i]);
-    storeTypeInfo(&pMem[i], encoding);
-    REGISTER_TRACE(pOp->p1+i, &pMem[i]);
+  u.ae.pMem = p->pResultSet = &aMem[pOp->p1];
+  for(u.ae.i=0; u.ae.i<pOp->p2; u.ae.i++){
+    assert( memIsValid(&u.ae.pMem[u.ae.i]) );
+    Deephemeralize(&u.ae.pMem[u.ae.i]);
+    assert( (u.ae.pMem[u.ae.i].flags & MEM_Ephem)==0
+            || (u.ae.pMem[u.ae.i].flags & (MEM_Str|MEM_Blob))==0 );
+    sqlite3VdbeMemNulTerminate(&u.ae.pMem[u.ae.i]);
+    sqlite3VdbeMemStoreType(&u.ae.pMem[u.ae.i]);
+    REGISTER_TRACE(pOp->p1+u.ae.i, &u.ae.pMem[u.ae.i]);
   }
   if( db->mallocFailed ) goto no_mem;
 
   /* Return SQLITE_ROW
   */
-  p->nCallback++;
   p->pc = pc + 1;
   rc = SQLITE_ROW;
   goto vdbe_return;
@@ -49884,33 +64643,37 @@ case OP_ResultRow: {
 ** to avoid a memcpy().
 */
 case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
+#if 0  /* local variables moved into u.af */
   i64 nByte;
+#endif /* local variables moved into u.af */
 
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
   assert( pIn1!=pOut );
   if( (pIn1->flags | pIn2->flags) & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
     break;
   }
-  ExpandBlob(pIn1);
+  if( ExpandBlob(pIn1) || ExpandBlob(pIn2) ) goto no_mem;
   Stringify(pIn1, encoding);
-  ExpandBlob(pIn2);
   Stringify(pIn2, encoding);
-  nByte = pIn1->n + pIn2->n;
-  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+  u.af.nByte = pIn1->n + pIn2->n;
+  if( u.af.nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
     goto too_big;
   }
   MemSetTypeFlag(pOut, MEM_Str);
-  if( sqlite3VdbeMemGrow(pOut, (int)nByte+2, pOut==pIn2) ){
+  if( sqlite3VdbeMemGrow(pOut, (int)u.af.nByte+2, pOut==pIn2) ){
     goto no_mem;
   }
   if( pOut!=pIn2 ){
     memcpy(pOut->z, pIn2->z, pIn2->n);
   }
   memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
-  pOut->z[nByte] = 0;
-  pOut->z[nByte+1] = 0;
+  pOut->z[u.af.nByte] = 0;
+  pOut->z[u.af.nByte+1] = 0;
   pOut->flags |= MEM_Term;
-  pOut->n = (int)nByte;
+  pOut->n = (int)u.af.nByte;
   pOut->enc = encoding;
   UPDATE_MAX_BLOBSIZE(pOut);
   break;
@@ -49938,9 +64701,9 @@ case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
 /* Opcode: Divide P1 P2 P3 * *
 **
 ** Divide the value in register P1 by the value in register P2
-** and store the result in register P3.  If the value in register P2
-** is zero, then the result is NULL.
-** If either input is NULL, the result is NULL.
+** and store the result in register P3 (P3=P2/P1). If the value in 
+** register P1 is zero, then the result is NULL. If either input is 
+** NULL, the result is NULL.
 */
 /* Opcode: Remainder P1 P2 P3 * *
 **
@@ -49954,71 +64717,79 @@ case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
 case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
 case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
 case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */
-  int flags;
+#if 0  /* local variables moved into u.ag */
+  int flags;      /* Combined MEM_* flags from both inputs */
+  i64 iA;         /* Integer value of left operand */
+  i64 iB;         /* Integer value of right operand */
+  double rA;      /* Real value of left operand */
+  double rB;      /* Real value of right operand */
+#endif /* local variables moved into u.ag */
+
+  pIn1 = &aMem[pOp->p1];
   applyNumericAffinity(pIn1);
+  pIn2 = &aMem[pOp->p2];
   applyNumericAffinity(pIn2);
-  flags = pIn1->flags | pIn2->flags;
-  if( (flags & MEM_Null)!=0 ) goto arithmetic_result_is_null;
+  pOut = &aMem[pOp->p3];
+  u.ag.flags = pIn1->flags | pIn2->flags;
+  if( (u.ag.flags & MEM_Null)!=0 ) goto arithmetic_result_is_null;
   if( (pIn1->flags & pIn2->flags & MEM_Int)==MEM_Int ){
-    i64 a, b;
-    a = pIn1->u.i;
-    b = pIn2->u.i;
+    u.ag.iA = pIn1->u.i;
+    u.ag.iB = pIn2->u.i;
     switch( pOp->opcode ){
-      case OP_Add:         b += a;       break;
-      case OP_Subtract:    b -= a;       break;
-      case OP_Multiply:    b *= a;       break;
+      case OP_Add:       if( sqlite3AddInt64(&u.ag.iB,u.ag.iA) ) goto fp_math;  break;
+      case OP_Subtract:  if( sqlite3SubInt64(&u.ag.iB,u.ag.iA) ) goto fp_math;  break;
+      case OP_Multiply:  if( sqlite3MulInt64(&u.ag.iB,u.ag.iA) ) goto fp_math;  break;
       case OP_Divide: {
-        if( a==0 ) goto arithmetic_result_is_null;
-        /* Dividing the largest possible negative 64-bit integer (1<<63) by 
-        ** -1 returns an integer too large to store in a 64-bit data-type. On
-        ** some architectures, the value overflows to (1<<63). On others,
-        ** a SIGFPE is issued. The following statement normalizes this
-        ** behavior so that all architectures behave as if integer 
-        ** overflow occurred.
-        */
-        if( a==-1 && b==SMALLEST_INT64 ) a = 1;
-        b /= a;
+        if( u.ag.iA==0 ) goto arithmetic_result_is_null;
+        if( u.ag.iA==-1 && u.ag.iB==SMALLEST_INT64 ) goto fp_math;
+        u.ag.iB /= u.ag.iA;
         break;
       }
       default: {
-        if( a==0 ) goto arithmetic_result_is_null;
-        if( a==-1 ) a = 1;
-        b %= a;
+        if( u.ag.iA==0 ) goto arithmetic_result_is_null;
+        if( u.ag.iA==-1 ) u.ag.iA = 1;
+        u.ag.iB %= u.ag.iA;
         break;
       }
     }
-    pOut->u.i = b;
+    pOut->u.i = u.ag.iB;
     MemSetTypeFlag(pOut, MEM_Int);
   }else{
-    double a, b;
-    a = sqlite3VdbeRealValue(pIn1);
-    b = sqlite3VdbeRealValue(pIn2);
+fp_math:
+    u.ag.rA = sqlite3VdbeRealValue(pIn1);
+    u.ag.rB = sqlite3VdbeRealValue(pIn2);
     switch( pOp->opcode ){
-      case OP_Add:         b += a;       break;
-      case OP_Subtract:    b -= a;       break;
-      case OP_Multiply:    b *= a;       break;
+      case OP_Add:         u.ag.rB += u.ag.rA;       break;
+      case OP_Subtract:    u.ag.rB -= u.ag.rA;       break;
+      case OP_Multiply:    u.ag.rB *= u.ag.rA;       break;
       case OP_Divide: {
-        if( a==0.0 ) goto arithmetic_result_is_null;
-        b /= a;
+        /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+        if( u.ag.rA==(double)0 ) goto arithmetic_result_is_null;
+        u.ag.rB /= u.ag.rA;
         break;
       }
       default: {
-        i64 ia = (i64)a;
-        i64 ib = (i64)b;
-        if( ia==0 ) goto arithmetic_result_is_null;
-        if( ia==-1 ) ia = 1;
-        b = (double)(ib % ia);
+        u.ag.iA = (i64)u.ag.rA;
+        u.ag.iB = (i64)u.ag.rB;
+        if( u.ag.iA==0 ) goto arithmetic_result_is_null;
+        if( u.ag.iA==-1 ) u.ag.iA = 1;
+        u.ag.rB = (double)(u.ag.iB % u.ag.iA);
         break;
       }
     }
-    if( sqlite3IsNaN(b) ){
+#ifdef SQLITE_OMIT_FLOATING_POINT
+    pOut->u.i = u.ag.rB;
+    MemSetTypeFlag(pOut, MEM_Int);
+#else
+    if( sqlite3IsNaN(u.ag.rB) ){
       goto arithmetic_result_is_null;
     }
-    pOut->r = b;
+    pOut->r = u.ag.rB;
     MemSetTypeFlag(pOut, MEM_Real);
-    if( (flags & MEM_Real)==0 ){
+    if( (u.ag.flags & MEM_Real)==0 ){
       sqlite3VdbeIntegerAffinity(pOut);
     }
+#endif
   }
   break;
 
@@ -50027,19 +64798,26 @@ arithmetic_result_is_null:
   break;
 }
 
-/* Opcode: CollSeq * * P4
+/* Opcode: CollSeq P1 * * P4
 **
 ** P4 is a pointer to a CollSeq struct. If the next call to a user function
 ** or aggregate calls sqlite3GetFuncCollSeq(), this collation sequence will
 ** be returned. This is used by the built-in min(), max() and nullif()
 ** functions.
 **
+** If P1 is not zero, then it is a register that a subsequent min() or
+** max() aggregate will set to 1 if the current row is not the minimum or
+** maximum.  The P1 register is initialized to 0 by this instruction.
+**
 ** The interface used by the implementation of the aforementioned functions
 ** to retrieve the collation sequence set by this opcode is not available
 ** publicly, only to user functions defined in func.c.
 */
 case OP_CollSeq: {
   assert( pOp->p4type==P4_COLLSEQ );
+  if( pOp->p1 ){
+    sqlite3VdbeMemSetInt64(&aMem[pOp->p1], 0);
+  }
   break;
 }
 
@@ -50060,95 +64838,104 @@ case OP_CollSeq: {
 ** See also: AggStep and AggFinal
 */
 case OP_Function: {
+#if 0  /* local variables moved into u.ah */
   int i;
   Mem *pArg;
   sqlite3_context ctx;
   sqlite3_value **apVal;
-  int n = pOp->p5;
+  int n;
+#endif /* local variables moved into u.ah */
 
-  apVal = p->apArg;
-  assert( apVal || n==0 );
+  u.ah.n = pOp->p5;
+  u.ah.apVal = p->apArg;
+  assert( u.ah.apVal || u.ah.n==0 );
+  assert( pOp->p3>0 && pOp->p3<=p->nMem );
+  pOut = &aMem[pOp->p3];
+  memAboutToChange(p, pOut);
 
-  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=p->nMem) );
-  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
-  pArg = &p->aMem[pOp->p2];
-  for(i=0; i<n; i++, pArg++){
-    apVal[i] = pArg;
-    storeTypeInfo(pArg, encoding);
-    REGISTER_TRACE(pOp->p2, pArg);
+  assert( u.ah.n==0 || (pOp->p2>0 && pOp->p2+u.ah.n<=p->nMem+1) );
+  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+u.ah.n );
+  u.ah.pArg = &aMem[pOp->p2];
+  for(u.ah.i=0; u.ah.i<u.ah.n; u.ah.i++, u.ah.pArg++){
+    assert( memIsValid(u.ah.pArg) );
+    u.ah.apVal[u.ah.i] = u.ah.pArg;
+    Deephemeralize(u.ah.pArg);
+    sqlite3VdbeMemStoreType(u.ah.pArg);
+    REGISTER_TRACE(pOp->p2+u.ah.i, u.ah.pArg);
   }
 
   assert( pOp->p4type==P4_FUNCDEF || pOp->p4type==P4_VDBEFUNC );
   if( pOp->p4type==P4_FUNCDEF ){
-    ctx.pFunc = pOp->p4.pFunc;
-    ctx.pVdbeFunc = 0;
+    u.ah.ctx.pFunc = pOp->p4.pFunc;
+    u.ah.ctx.pVdbeFunc = 0;
   }else{
-    ctx.pVdbeFunc = (VdbeFunc*)pOp->p4.pVdbeFunc;
-    ctx.pFunc = ctx.pVdbeFunc->pFunc;
+    u.ah.ctx.pVdbeFunc = (VdbeFunc*)pOp->p4.pVdbeFunc;
+    u.ah.ctx.pFunc = u.ah.ctx.pVdbeFunc->pFunc;
   }
 
-  assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  pOut = &p->aMem[pOp->p3];
-  ctx.s.flags = MEM_Null;
-  ctx.s.db = db;
-  ctx.s.xDel = 0;
-  ctx.s.zMalloc = 0;
+  u.ah.ctx.s.flags = MEM_Null;
+  u.ah.ctx.s.db = db;
+  u.ah.ctx.s.xDel = 0;
+  u.ah.ctx.s.zMalloc = 0;
 
   /* The output cell may already have a buffer allocated. Move
-  ** the pointer to ctx.s so in case the user-function can use
+  ** the pointer to u.ah.ctx.s so in case the user-function can use
   ** the already allocated buffer instead of allocating a new one.
   */
-  sqlite3VdbeMemMove(&ctx.s, pOut);
-  MemSetTypeFlag(&ctx.s, MEM_Null);
+  sqlite3VdbeMemMove(&u.ah.ctx.s, pOut);
+  MemSetTypeFlag(&u.ah.ctx.s, MEM_Null);
 
-  ctx.isError = 0;
-  if( ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
-    assert( pOp>p->aOp );
+  u.ah.ctx.isError = 0;
+  if( u.ah.ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
+    assert( pOp>aOp );
     assert( pOp[-1].p4type==P4_COLLSEQ );
     assert( pOp[-1].opcode==OP_CollSeq );
-    ctx.pColl = pOp[-1].p4.pColl;
+    u.ah.ctx.pColl = pOp[-1].p4.pColl;
   }
-  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  (*ctx.pFunc->xFunc)(&ctx, n, apVal);
-  if( sqlite3SafetyOn(db) ){
-    sqlite3VdbeMemRelease(&ctx.s);
-    goto abort_due_to_misuse;
+  db->lastRowid = lastRowid;
+  (*u.ah.ctx.pFunc->xFunc)(&u.ah.ctx, u.ah.n, u.ah.apVal); /* IMP: R-24505-23230 */
+  lastRowid = db->lastRowid;
+
+  /* If any auxiliary data functions have been called by this user function,
+  ** immediately call the destructor for any non-static values.
+  */
+  if( u.ah.ctx.pVdbeFunc ){
+    sqlite3VdbeDeleteAuxData(u.ah.ctx.pVdbeFunc, pOp->p1);
+    pOp->p4.pVdbeFunc = u.ah.ctx.pVdbeFunc;
+    pOp->p4type = P4_VDBEFUNC;
   }
+
   if( db->mallocFailed ){
     /* Even though a malloc() has failed, the implementation of the
     ** user function may have called an sqlite3_result_XXX() function
     ** to return a value. The following call releases any resources
     ** associated with such a value.
-    **
-    ** Note: Maybe MemRelease() should be called if sqlite3SafetyOn()
-    ** fails also (the if(...) statement above). But if people are
-    ** misusing sqlite, they have bigger problems than a leaked value.
     */
-    sqlite3VdbeMemRelease(&ctx.s);
+    sqlite3VdbeMemRelease(&u.ah.ctx.s);
     goto no_mem;
   }
 
-  /* If any auxiliary data functions have been called by this user function,
-  ** immediately call the destructor for any non-static values.
-  */
-  if( ctx.pVdbeFunc ){
-    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
-    pOp->p4.pVdbeFunc = ctx.pVdbeFunc;
-    pOp->p4type = P4_VDBEFUNC;
-  }
-
   /* If the function returned an error, throw an exception */
-  if( ctx.isError ){
-    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&ctx.s));
-    rc = ctx.isError;
+  if( u.ah.ctx.isError ){
+    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&u.ah.ctx.s));
+    rc = u.ah.ctx.isError;
   }
 
   /* Copy the result of the function into register P3 */
-  sqlite3VdbeChangeEncoding(&ctx.s, encoding);
-  sqlite3VdbeMemMove(pOut, &ctx.s);
+  sqlite3VdbeChangeEncoding(&u.ah.ctx.s, encoding);
+  sqlite3VdbeMemMove(pOut, &u.ah.ctx.s);
   if( sqlite3VdbeMemTooBig(pOut) ){
     goto too_big;
   }
+
+#if 0
+  /* The app-defined function has done something that as caused this
+  ** statement to expire.  (Perhaps the function called sqlite3_exec()
+  ** with a CREATE TABLE statement.)
+  */
+  if( p->expired ) rc = SQLITE_ABORT;
+#endif
+
   REGISTER_TRACE(pOp->p3, pOut);
   UPDATE_MAX_BLOBSIZE(pOut);
   break;
@@ -50169,7 +64956,7 @@ case OP_Function: {
 /* Opcode: ShiftLeft P1 P2 P3 * *
 **
 ** Shift the integer value in register P2 to the left by the
-** number of bits specified by the integer in regiser P1.
+** number of bits specified by the integer in register P1.
 ** Store the result in register P3.
 ** If either input is NULL, the result is NULL.
 */
@@ -50184,22 +64971,52 @@ case OP_BitAnd:                 /* same as TK_BITAND, in1, in2, out3 */
 case OP_BitOr:                  /* same as TK_BITOR, in1, in2, out3 */
 case OP_ShiftLeft:              /* same as TK_LSHIFT, in1, in2, out3 */
 case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
-  i64 a, b;
+#if 0  /* local variables moved into u.ai */
+  i64 iA;
+  u64 uA;
+  i64 iB;
+  u8 op;
+#endif /* local variables moved into u.ai */
 
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
   if( (pIn1->flags | pIn2->flags) & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
     break;
   }
-  a = sqlite3VdbeIntValue(pIn2);
-  b = sqlite3VdbeIntValue(pIn1);
-  switch( pOp->opcode ){
-    case OP_BitAnd:      a &= b;     break;
-    case OP_BitOr:       a |= b;     break;
-    case OP_ShiftLeft:   a <<= b;    break;
-    default:  assert( pOp->opcode==OP_ShiftRight );
-                         a >>= b;    break;
+  u.ai.iA = sqlite3VdbeIntValue(pIn2);
+  u.ai.iB = sqlite3VdbeIntValue(pIn1);
+  u.ai.op = pOp->opcode;
+  if( u.ai.op==OP_BitAnd ){
+    u.ai.iA &= u.ai.iB;
+  }else if( u.ai.op==OP_BitOr ){
+    u.ai.iA |= u.ai.iB;
+  }else if( u.ai.iB!=0 ){
+    assert( u.ai.op==OP_ShiftRight || u.ai.op==OP_ShiftLeft );
+
+    /* If shifting by a negative amount, shift in the other direction */
+    if( u.ai.iB<0 ){
+      assert( OP_ShiftRight==OP_ShiftLeft+1 );
+      u.ai.op = 2*OP_ShiftLeft + 1 - u.ai.op;
+      u.ai.iB = u.ai.iB>(-64) ? -u.ai.iB : 64;
+    }
+
+    if( u.ai.iB>=64 ){
+      u.ai.iA = (u.ai.iA>=0 || u.ai.op==OP_ShiftLeft) ? 0 : -1;
+    }else{
+      memcpy(&u.ai.uA, &u.ai.iA, sizeof(u.ai.uA));
+      if( u.ai.op==OP_ShiftLeft ){
+        u.ai.uA <<= u.ai.iB;
+      }else{
+        u.ai.uA >>= u.ai.iB;
+        /* Sign-extend on a right shift of a negative number */
+        if( u.ai.iA<0 ) u.ai.uA |= ((((u64)0xffffffff)<<32)|0xffffffff) << (64-u.ai.iB);
+      }
+      memcpy(&u.ai.iA, &u.ai.uA, sizeof(u.ai.iA));
+    }
   }
-  pOut->u.i = a;
+  pOut->u.i = u.ai.iA;
   MemSetTypeFlag(pOut, MEM_Int);
   break;
 }
@@ -50212,6 +65029,8 @@ case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
 ** To force any register to be an integer, just add 0.
 */
 case OP_AddImm: {            /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  memAboutToChange(p, pIn1);
   sqlite3VdbeMemIntegerify(pIn1);
   pIn1->u.i += pOp->p2;
   break;
@@ -50225,6 +65044,7 @@ case OP_AddImm: {            /* in1 */
 ** raise an SQLITE_MISMATCH exception.
 */
 case OP_MustBeInt: {            /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   applyAffinity(pIn1, SQLITE_AFF_NUMERIC, encoding);
   if( (pIn1->flags & MEM_Int)==0 ){
     if( pOp->p2==0 ){
@@ -50239,6 +65059,7 @@ case OP_MustBeInt: {            /* jump, in1 */
   break;
 }
 
+#ifndef SQLITE_OMIT_FLOATING_POINT
 /* Opcode: RealAffinity P1 * * * *
 **
 ** If register P1 holds an integer convert it to a real value.
@@ -50249,11 +65070,13 @@ case OP_MustBeInt: {            /* jump, in1 */
 ** to have only a real value.
 */
 case OP_RealAffinity: {                  /* in1 */
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Int ){
     sqlite3VdbeMemRealify(pIn1);
   }
   break;
 }
+#endif
 
 #ifndef SQLITE_OMIT_CAST
 /* Opcode: ToText P1 * * * *
@@ -50266,6 +65089,8 @@ case OP_RealAffinity: {                  /* in1 */
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToText: {                  /* same as TK_TO_TEXT, in1 */
+  pIn1 = &aMem[pOp->p1];
+  memAboutToChange(p, pIn1);
   if( pIn1->flags & MEM_Null ) break;
   assert( MEM_Str==(MEM_Blob>>3) );
   pIn1->flags |= (pIn1->flags&MEM_Blob)>>3;
@@ -50287,6 +65112,7 @@ case OP_ToText: {                  /* same as TK_TO_TEXT, in1 */
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToBlob: {                  /* same as TK_TO_BLOB, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Null ) break;
   if( (pIn1->flags & MEM_Blob)==0 ){
     applyAffinity(pIn1, SQLITE_AFF_TEXT, encoding);
@@ -50310,16 +65136,15 @@ case OP_ToBlob: {                  /* same as TK_TO_BLOB, in1 */
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToNumeric: {                  /* same as TK_TO_NUMERIC, in1 */
-  if( (pIn1->flags & (MEM_Null|MEM_Int|MEM_Real))==0 ){
-    sqlite3VdbeMemNumerify(pIn1);
-  }
+  pIn1 = &aMem[pOp->p1];
+  sqlite3VdbeMemNumerify(pIn1);
   break;
 }
 #endif /* SQLITE_OMIT_CAST */
 
 /* Opcode: ToInt P1 * * * *
 **
-** Force the value in register P1 be an integer.  If
+** Force the value in register P1 to be an integer.  If
 ** The value is currently a real number, drop its fractional part.
 ** If the value is text or blob, try to convert it to an integer using the
 ** equivalent of atoi() and store 0 if no such conversion is possible.
@@ -50327,13 +65152,14 @@ case OP_ToNumeric: {                  /* same as TK_TO_NUMERIC, in1 */
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToInt: {                  /* same as TK_TO_INT, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( (pIn1->flags & MEM_Null)==0 ){
     sqlite3VdbeMemIntegerify(pIn1);
   }
   break;
 }
 
-#ifndef SQLITE_OMIT_CAST
+#if !defined(SQLITE_OMIT_CAST) && !defined(SQLITE_OMIT_FLOATING_POINT)
 /* Opcode: ToReal P1 * * * *
 **
 ** Force the value in register P1 to be a floating point number.
@@ -50344,12 +65170,14 @@ case OP_ToInt: {                  /* same as TK_TO_INT, in1 */
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
+  pIn1 = &aMem[pOp->p1];
+  memAboutToChange(p, pIn1);
   if( (pIn1->flags & MEM_Null)==0 ){
     sqlite3VdbeMemRealify(pIn1);
   }
   break;
 }
-#endif /* SQLITE_OMIT_CAST */
+#endif /* !defined(SQLITE_OMIT_CAST) && !defined(SQLITE_OMIT_FLOATING_POINT) */
 
 /* Opcode: Lt P1 P2 P3 P4 P5
 **
@@ -50358,7 +65186,7 @@ case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
 **
 ** If the SQLITE_JUMPIFNULL bit of P5 is set and either reg(P1) or
 ** reg(P3) is NULL then take the jump.  If the SQLITE_JUMPIFNULL 
-** bit is clear then fall thru if either operand is NULL.
+** bit is clear then fall through if either operand is NULL.
 **
 ** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
 ** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made 
@@ -50386,12 +65214,24 @@ case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
 ** This works just like the Lt opcode except that the jump is taken if
 ** the operands in registers P1 and P3 are not equal.  See the Lt opcode for
 ** additional information.
+**
+** If SQLITE_NULLEQ is set in P5 then the result of comparison is always either
+** true or false and is never NULL.  If both operands are NULL then the result
+** of comparison is false.  If either operand is NULL then the result is true.
+** If neither operand is NULL the result is the same as it would be if
+** the SQLITE_NULLEQ flag were omitted from P5.
 */
 /* Opcode: Eq P1 P2 P3 P4 P5
 **
 ** This works just like the Lt opcode except that the jump is taken if
 ** the operands in registers P1 and P3 are equal.
 ** See the Lt opcode for additional information.
+**
+** If SQLITE_NULLEQ is set in P5 then the result of comparison is always either
+** true or false and is never NULL.  If both operands are NULL then the result
+** of comparison is true.  If either operand is NULL then the result is false.
+** If neither operand is NULL the result is the same as it would be if
+** the SQLITE_NULLEQ flag were omitted from P5.
 */
 /* Opcode: Le P1 P2 P3 P4 P5
 **
@@ -50417,60 +65257,82 @@ case OP_Lt:               /* same as TK_LT, jump, in1, in3 */
 case OP_Le:               /* same as TK_LE, jump, in1, in3 */
 case OP_Gt:               /* same as TK_GT, jump, in1, in3 */
 case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
-  int flags;
-  int res;
-  char affinity;
+#if 0  /* local variables moved into u.aj */
+  int res;            /* Result of the comparison of pIn1 against pIn3 */
+  char affinity;      /* Affinity to use for comparison */
+  u16 flags1;         /* Copy of initial value of pIn1->flags */
+  u16 flags3;         /* Copy of initial value of pIn3->flags */
+#endif /* local variables moved into u.aj */
 
-  flags = pIn1->flags|pIn3->flags;
-
-  if( flags&MEM_Null ){
-    /* If either operand is NULL then the result is always NULL.
-    ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
-    */
-    if( pOp->p5 & SQLITE_STOREP2 ){
-      pOut = &p->aMem[pOp->p2];
-      MemSetTypeFlag(pOut, MEM_Null);
-      REGISTER_TRACE(pOp->p2, pOut);
-    }else if( pOp->p5 & SQLITE_JUMPIFNULL ){
-      pc = pOp->p2-1;
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  u.aj.flags1 = pIn1->flags;
+  u.aj.flags3 = pIn3->flags;
+  if( (u.aj.flags1 | u.aj.flags3)&MEM_Null ){
+    /* One or both operands are NULL */
+    if( pOp->p5 & SQLITE_NULLEQ ){
+      /* If SQLITE_NULLEQ is set (which will only happen if the operator is
+      ** OP_Eq or OP_Ne) then take the jump or not depending on whether
+      ** or not both operands are null.
+      */
+      assert( pOp->opcode==OP_Eq || pOp->opcode==OP_Ne );
+      u.aj.res = (u.aj.flags1 & u.aj.flags3 & MEM_Null)==0;
+    }else{
+      /* SQLITE_NULLEQ is clear and at least one operand is NULL,
+      ** then the result is always NULL.
+      ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
+      */
+      if( pOp->p5 & SQLITE_STOREP2 ){
+        pOut = &aMem[pOp->p2];
+        MemSetTypeFlag(pOut, MEM_Null);
+        REGISTER_TRACE(pOp->p2, pOut);
+      }else if( pOp->p5 & SQLITE_JUMPIFNULL ){
+        pc = pOp->p2-1;
+      }
+      break;
+    }
+  }else{
+    /* Neither operand is NULL.  Do a comparison. */
+    u.aj.affinity = pOp->p5 & SQLITE_AFF_MASK;
+    if( u.aj.affinity ){
+      applyAffinity(pIn1, u.aj.affinity, encoding);
+      applyAffinity(pIn3, u.aj.affinity, encoding);
+      if( db->mallocFailed ) goto no_mem;
     }
-    break;
-  }
 
-  affinity = pOp->p5 & SQLITE_AFF_MASK;
-  if( affinity ){
-    applyAffinity(pIn1, affinity, encoding);
-    applyAffinity(pIn3, affinity, encoding);
-    if( db->mallocFailed ) goto no_mem;
+    assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
+    ExpandBlob(pIn1);
+    ExpandBlob(pIn3);
+    u.aj.res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
   }
-
-  assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
-  ExpandBlob(pIn1);
-  ExpandBlob(pIn3);
-  res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
   switch( pOp->opcode ){
-    case OP_Eq:    res = res==0;     break;
-    case OP_Ne:    res = res!=0;     break;
-    case OP_Lt:    res = res<0;      break;
-    case OP_Le:    res = res<=0;     break;
-    case OP_Gt:    res = res>0;      break;
-    default:       res = res>=0;     break;
+    case OP_Eq:    u.aj.res = u.aj.res==0;     break;
+    case OP_Ne:    u.aj.res = u.aj.res!=0;     break;
+    case OP_Lt:    u.aj.res = u.aj.res<0;      break;
+    case OP_Le:    u.aj.res = u.aj.res<=0;     break;
+    case OP_Gt:    u.aj.res = u.aj.res>0;      break;
+    default:       u.aj.res = u.aj.res>=0;     break;
   }
 
   if( pOp->p5 & SQLITE_STOREP2 ){
-    pOut = &p->aMem[pOp->p2];
+    pOut = &aMem[pOp->p2];
+    memAboutToChange(p, pOut);
     MemSetTypeFlag(pOut, MEM_Int);
-    pOut->u.i = res;
+    pOut->u.i = u.aj.res;
     REGISTER_TRACE(pOp->p2, pOut);
-  }else if( res ){
+  }else if( u.aj.res ){
     pc = pOp->p2-1;
   }
+
+  /* Undo any changes made by applyAffinity() to the input registers. */
+  pIn1->flags = (pIn1->flags&~MEM_TypeMask) | (u.aj.flags1&MEM_TypeMask);
+  pIn3->flags = (pIn3->flags&~MEM_TypeMask) | (u.aj.flags3&MEM_TypeMask);
   break;
 }
 
 /* Opcode: Permutation * * * P4 *
 **
-** Set the permuation used by the OP_Compare operator to be the array
+** Set the permutation used by the OP_Compare operator to be the array
 ** of integers in P4.
 **
 ** The permutation is only valid until the next OP_Permutation, OP_Compare,
@@ -50486,8 +65348,8 @@ case OP_Permutation: {
 
 /* Opcode: Compare P1 P2 P3 P4 *
 **
-** Compare to vectors of registers in reg(P1)..reg(P1+P3-1) (all this
-** one "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
+** Compare two vectors of registers in reg(P1)..reg(P1+P3-1) (call this
+** vector "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
 ** the comparison for use by the next OP_Jump instruct.
 **
 ** P4 is a KeyInfo structure that defines collating sequences and sort
@@ -50499,27 +65361,46 @@ case OP_Permutation: {
 ** and strings are less than blobs.
 */
 case OP_Compare: {
-  int n = pOp->p3;
-  int i, p1, p2;
-  const KeyInfo *pKeyInfo = pOp->p4.pKeyInfo;
-  assert( n>0 );
-  assert( pKeyInfo!=0 );
-  p1 = pOp->p1;
-  assert( p1>0 && p1+n-1<p->nMem );
-  p2 = pOp->p2;
-  assert( p2>0 && p2+n-1<p->nMem );
-  for(i=0; i<n; i++){
-    int idx = aPermute ? aPermute[i] : i;
-    CollSeq *pColl;    /* Collating sequence to use on this term */
-    int bRev;          /* True for DESCENDING sort order */
-    REGISTER_TRACE(p1+idx, &p->aMem[p1+idx]);
-    REGISTER_TRACE(p2+idx, &p->aMem[p2+idx]);
-    assert( i<pKeyInfo->nField );
-    pColl = pKeyInfo->aColl[i];
-    bRev = pKeyInfo->aSortOrder[i];
-    iCompare = sqlite3MemCompare(&p->aMem[p1+idx], &p->aMem[p2+idx], pColl);
+#if 0  /* local variables moved into u.ak */
+  int n;
+  int i;
+  int p1;
+  int p2;
+  const KeyInfo *pKeyInfo;
+  int idx;
+  CollSeq *pColl;    /* Collating sequence to use on this term */
+  int bRev;          /* True for DESCENDING sort order */
+#endif /* local variables moved into u.ak */
+
+  u.ak.n = pOp->p3;
+  u.ak.pKeyInfo = pOp->p4.pKeyInfo;
+  assert( u.ak.n>0 );
+  assert( u.ak.pKeyInfo!=0 );
+  u.ak.p1 = pOp->p1;
+  u.ak.p2 = pOp->p2;
+#if SQLITE_DEBUG
+  if( aPermute ){
+    int k, mx = 0;
+    for(k=0; k<u.ak.n; k++) if( aPermute[k]>mx ) mx = aPermute[k];
+    assert( u.ak.p1>0 && u.ak.p1+mx<=p->nMem+1 );
+    assert( u.ak.p2>0 && u.ak.p2+mx<=p->nMem+1 );
+  }else{
+    assert( u.ak.p1>0 && u.ak.p1+u.ak.n<=p->nMem+1 );
+    assert( u.ak.p2>0 && u.ak.p2+u.ak.n<=p->nMem+1 );
+  }
+#endif /* SQLITE_DEBUG */
+  for(u.ak.i=0; u.ak.i<u.ak.n; u.ak.i++){
+    u.ak.idx = aPermute ? aPermute[u.ak.i] : u.ak.i;
+    assert( memIsValid(&aMem[u.ak.p1+u.ak.idx]) );
+    assert( memIsValid(&aMem[u.ak.p2+u.ak.idx]) );
+    REGISTER_TRACE(u.ak.p1+u.ak.idx, &aMem[u.ak.p1+u.ak.idx]);
+    REGISTER_TRACE(u.ak.p2+u.ak.idx, &aMem[u.ak.p2+u.ak.idx]);
+    assert( u.ak.i<u.ak.pKeyInfo->nField );
+    u.ak.pColl = u.ak.pKeyInfo->aColl[u.ak.i];
+    u.ak.bRev = u.ak.pKeyInfo->aSortOrder[u.ak.i];
+    iCompare = sqlite3MemCompare(&aMem[u.ak.p1+u.ak.idx], &aMem[u.ak.p2+u.ak.idx], u.ak.pColl);
     if( iCompare ){
-      if( bRev ) iCompare = -iCompare;
+      if( u.ak.bRev ) iCompare = -iCompare;
       break;
     }
   }
@@ -50564,29 +65445,35 @@ case OP_Jump: {             /* jump */
 */
 case OP_And:              /* same as TK_AND, in1, in2, out3 */
 case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
-  int v1, v2;    /* 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+#if 0  /* local variables moved into u.al */
+  int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+  int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+#endif /* local variables moved into u.al */
 
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Null ){
-    v1 = 2;
+    u.al.v1 = 2;
   }else{
-    v1 = sqlite3VdbeIntValue(pIn1)!=0;
+    u.al.v1 = sqlite3VdbeIntValue(pIn1)!=0;
   }
+  pIn2 = &aMem[pOp->p2];
   if( pIn2->flags & MEM_Null ){
-    v2 = 2;
+    u.al.v2 = 2;
   }else{
-    v2 = sqlite3VdbeIntValue(pIn2)!=0;
+    u.al.v2 = sqlite3VdbeIntValue(pIn2)!=0;
   }
   if( pOp->opcode==OP_And ){
     static const unsigned char and_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
-    v1 = and_logic[v1*3+v2];
+    u.al.v1 = and_logic[u.al.v1*3+u.al.v2];
   }else{
     static const unsigned char or_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
-    v1 = or_logic[v1*3+v2];
+    u.al.v1 = or_logic[u.al.v1*3+u.al.v2];
   }
-  if( v1==2 ){
+  pOut = &aMem[pOp->p3];
+  if( u.al.v1==2 ){
     MemSetTypeFlag(pOut, MEM_Null);
   }else{
-    pOut->u.i = v1;
+    pOut->u.i = u.al.v1;
     MemSetTypeFlag(pOut, MEM_Int);
   }
   break;
@@ -50598,8 +65485,9 @@ case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
 ** boolean complement in register P2.  If the value in register P1 is 
 ** NULL, then a NULL is stored in P2.
 */
-case OP_Not: {                /* same as TK_NOT, in1 */
-  pOut = &p->aMem[pOp->p2];
+case OP_Not: {                /* same as TK_NOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   if( pIn1->flags & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
   }else{
@@ -50614,8 +65502,9 @@ case OP_Not: {                /* same as TK_NOT, in1 */
 ** ones-complement of the P1 value into register P2.  If P1 holds
 ** a NULL then store a NULL in P2.
 */
-case OP_BitNot: {             /* same as TK_BITNOT, in1 */
-  pOut = &p->aMem[pOp->p2];
+case OP_BitNot: {             /* same as TK_BITNOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   if( pIn1->flags & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
   }else{
@@ -50624,53 +65513,66 @@ case OP_BitNot: {             /* same as TK_BITNOT, in1 */
   break;
 }
 
+/* Opcode: Once P1 P2 * * *
+**
+** Check if OP_Once flag P1 is set. If so, jump to instruction P2. Otherwise,
+** set the flag and fall through to the next instruction.
+**
+** See also: JumpOnce
+*/
+case OP_Once: {             /* jump */
+  assert( pOp->p1<p->nOnceFlag );
+  if( p->aOnceFlag[pOp->p1] ){
+    pc = pOp->p2-1;
+  }else{
+    p->aOnceFlag[pOp->p1] = 1;
+  }
+  break;
+}
+
 /* Opcode: If P1 P2 P3 * *
 **
-** Jump to P2 if the value in register P1 is true.  The value is
+** Jump to P2 if the value in register P1 is true.  The value
 ** is considered true if it is numeric and non-zero.  If the value
-** in P1 is NULL then take the jump if P3 is true.
+** in P1 is NULL then take the jump if P3 is non-zero.
 */
 /* Opcode: IfNot P1 P2 P3 * *
 **
-** Jump to P2 if the value in register P1 is False.  The value is
-** is considered true if it has a numeric value of zero.  If the value
-** in P1 is NULL then take the jump if P3 is true.
+** Jump to P2 if the value in register P1 is False.  The value
+** is considered false if it has a numeric value of zero.  If the value
+** in P1 is NULL then take the jump if P3 is zero.
 */
 case OP_If:                 /* jump, in1 */
 case OP_IfNot: {            /* jump, in1 */
+#if 0  /* local variables moved into u.am */
   int c;
+#endif /* local variables moved into u.am */
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Null ){
-    c = pOp->p3;
+    u.am.c = pOp->p3;
   }else{
 #ifdef SQLITE_OMIT_FLOATING_POINT
-    c = sqlite3VdbeIntValue(pIn1);
+    u.am.c = sqlite3VdbeIntValue(pIn1)!=0;
 #else
-    c = sqlite3VdbeRealValue(pIn1)!=0.0;
+    u.am.c = sqlite3VdbeRealValue(pIn1)!=0.0;
 #endif
-    if( pOp->opcode==OP_IfNot ) c = !c;
+    if( pOp->opcode==OP_IfNot ) u.am.c = !u.am.c;
   }
-  if( c ){
+  if( u.am.c ){
     pc = pOp->p2-1;
   }
   break;
 }
 
-/* Opcode: IsNull P1 P2 P3 * *
+/* Opcode: IsNull P1 P2 * * *
 **
-** Jump to P2 if the value in register P1 is NULL.  If P3 is greater
-** than zero, then check all values reg(P1), reg(P1+1), 
-** reg(P1+2), ..., reg(P1+P3-1).
+** Jump to P2 if the value in register P1 is NULL.
 */
 case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
-  int n = pOp->p3;
-  assert( pOp->p3==0 || pOp->p1>0 );
-  do{
-    if( (pIn1->flags & MEM_Null)!=0 ){
-      pc = pOp->p2 - 1;
-      break;
-    }
-    pIn1++;
-  }while( --n > 0 );
+  pIn1 = &aMem[pOp->p1];
+  if( (pIn1->flags & MEM_Null)!=0 ){
+    pc = pOp->p2 - 1;
+  }
   break;
 }
 
@@ -50679,33 +65581,14 @@ case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
 ** Jump to P2 if the value in register P1 is not NULL.  
 */
 case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( (pIn1->flags & MEM_Null)==0 ){
     pc = pOp->p2 - 1;
   }
   break;
 }
 
-/* Opcode: SetNumColumns * P2 * * *
-**
-** This opcode sets the number of columns for the cursor opened by the
-** following instruction to P2.
-**
-** An OP_SetNumColumns is only useful if it occurs immediately before 
-** one of the following opcodes:
-**
-**     OpenRead
-**     OpenWrite
-**     OpenPseudo
-**
-** If the OP_Column opcode is to be executed on a cursor, then
-** this opcode must be present immediately before the opcode that
-** opens the cursor.
-*/
-case OP_SetNumColumns: {
-  break;
-}
-
-/* Opcode: Column P1 P2 P3 P4 *
+/* Opcode: Column P1 P2 P3 P4 P5
 **
 ** Interpret the data that cursor P1 points to as a structure built using
 ** the MakeRecord instruction.  (See the MakeRecord opcode for additional
@@ -50718,12 +65601,24 @@ case OP_SetNumColumns: {
 ** If the column contains fewer than P2 fields, then extract a NULL.  Or,
 ** if the P4 argument is a P4_MEM use the value of the P4 argument as
 ** the result.
+**
+** If the OPFLAG_CLEARCACHE bit is set on P5 and P1 is a pseudo-table cursor,
+** then the cache of the cursor is reset prior to extracting the column.
+** The first OP_Column against a pseudo-table after the value of the content
+** register has changed should have this bit set.
+**
+** If the OPFLAG_LENGTHARG and OPFLAG_TYPEOFARG bits are set on P5 when
+** the result is guaranteed to only be used as the argument of a length()
+** or typeof() function, respectively.  The loading of large blobs can be
+** skipped for length() and all content loading can be skipped for typeof().
 */
 case OP_Column: {
-  int payloadSize;   /* Number of bytes in the record */
-  int p1 = pOp->p1;  /* P1 value of the opcode */
-  int p2 = pOp->p2;  /* column number to retrieve */
-  VdbeCursor *pC = 0;/* The VDBE cursor */
+#if 0  /* local variables moved into u.an */
+  u32 payloadSize;   /* Number of bytes in the record */
+  i64 payloadSize64; /* Number of bytes in the record */
+  int p1;            /* P1 value of the opcode */
+  int p2;            /* column number to retrieve */
+  VdbeCursor *pC;    /* The VDBE cursor */
   char *zRec;        /* Pointer to complete record-data */
   BtCursor *pCrsr;   /* The BTree cursor */
   u32 *aType;        /* aType[i] holds the numeric type of the i-th column */
@@ -50734,114 +65629,164 @@ case OP_Column: {
   char *zData;       /* Part of the record being decoded */
   Mem *pDest;        /* Where to write the extracted value */
   Mem sMem;          /* For storing the record being decoded */
+  u8 *zIdx;          /* Index into header */
+  u8 *zEndHdr;       /* Pointer to first byte after the header */
+  u32 offset;        /* Offset into the data */
+  u32 szField;       /* Number of bytes in the content of a field */
+  int szHdr;         /* Size of the header size field at start of record */
+  int avail;         /* Number of bytes of available data */
+  u32 t;             /* A type code from the record header */
+  Mem *pReg;         /* PseudoTable input register */
+#endif /* local variables moved into u.an */
 
-  memset(&sMem, 0, sizeof(sMem));
-  assert( p1<p->nCursor );
+
+  u.an.p1 = pOp->p1;
+  u.an.p2 = pOp->p2;
+  u.an.pC = 0;
+  memset(&u.an.sMem, 0, sizeof(u.an.sMem));
+  assert( u.an.p1<p->nCursor );
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  pDest = &p->aMem[pOp->p3];
-  MemSetTypeFlag(pDest, MEM_Null);
+  u.an.pDest = &aMem[pOp->p3];
+  memAboutToChange(p, u.an.pDest);
+  u.an.zRec = 0;
 
-  /* This block sets the variable payloadSize to be the total number of
+  /* This block sets the variable u.an.payloadSize to be the total number of
   ** bytes in the record.
   **
-  ** zRec is set to be the complete text of the record if it is available.
+  ** u.an.zRec is set to be the complete text of the record if it is available.
   ** The complete record text is always available for pseudo-tables
   ** If the record is stored in a cursor, the complete record text
-  ** might be available in the  pC->aRow cache.  Or it might not be.
-  ** If the data is unavailable,  zRec is set to NULL.
+  ** might be available in the  u.an.pC->aRow cache.  Or it might not be.
+  ** If the data is unavailable,  u.an.zRec is set to NULL.
   **
   ** We also compute the number of columns in the record.  For cursors,
   ** the number of columns is stored in the VdbeCursor.nField element.
   */
-  pC = p->apCsr[p1];
-  assert( pC!=0 );
+  u.an.pC = p->apCsr[u.an.p1];
+  assert( u.an.pC!=0 );
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-  assert( pC->pVtabCursor==0 );
+  assert( u.an.pC->pVtabCursor==0 );
 #endif
-  if( pC->pCursor!=0 ){
+  u.an.pCrsr = u.an.pC->pCursor;
+  if( u.an.pCrsr!=0 ){
     /* The record is stored in a B-Tree */
-    rc = sqlite3VdbeCursorMoveto(pC);
+    rc = sqlite3VdbeCursorMoveto(u.an.pC);
     if( rc ) goto abort_due_to_error;
-    zRec = 0;
-    pCrsr = pC->pCursor;
-    if( pC->nullRow ){
-      payloadSize = 0;
-    }else if( pC->cacheStatus==p->cacheCtr ){
-      payloadSize = pC->payloadSize;
-      zRec = (char*)pC->aRow;
-    }else if( pC->isIndex ){
-      i64 payloadSize64;
-      sqlite3BtreeKeySize(pCrsr, &payloadSize64);
-      payloadSize = (int)payloadSize64;
+    if( u.an.pC->nullRow ){
+      u.an.payloadSize = 0;
+    }else if( u.an.pC->cacheStatus==p->cacheCtr ){
+      u.an.payloadSize = u.an.pC->payloadSize;
+      u.an.zRec = (char*)u.an.pC->aRow;
+    }else if( u.an.pC->isIndex ){
+      assert( sqlite3BtreeCursorIsValid(u.an.pCrsr) );
+      VVA_ONLY(rc =) sqlite3BtreeKeySize(u.an.pCrsr, &u.an.payloadSize64);
+      assert( rc==SQLITE_OK );   /* True because of CursorMoveto() call above */
+      /* sqlite3BtreeParseCellPtr() uses getVarint32() to extract the
+      ** payload size, so it is impossible for u.an.payloadSize64 to be
+      ** larger than 32 bits. */
+      assert( (u.an.payloadSize64 & SQLITE_MAX_U32)==(u64)u.an.payloadSize64 );
+      u.an.payloadSize = (u32)u.an.payloadSize64;
     }else{
-      sqlite3BtreeDataSize(pCrsr, (u32 *)&payloadSize);
+      assert( sqlite3BtreeCursorIsValid(u.an.pCrsr) );
+      VVA_ONLY(rc =) sqlite3BtreeDataSize(u.an.pCrsr, &u.an.payloadSize);
+      assert( rc==SQLITE_OK );   /* DataSize() cannot fail */
     }
-    nField = pC->nField;
+  }else if( ALWAYS(u.an.pC->pseudoTableReg>0) ){
+    u.an.pReg = &aMem[u.an.pC->pseudoTableReg];
+    assert( u.an.pReg->flags & MEM_Blob );
+    assert( memIsValid(u.an.pReg) );
+    u.an.payloadSize = u.an.pReg->n;
+    u.an.zRec = u.an.pReg->z;
+    u.an.pC->cacheStatus = (pOp->p5&OPFLAG_CLEARCACHE) ? CACHE_STALE : p->cacheCtr;
+    assert( u.an.payloadSize==0 || u.an.zRec!=0 );
   }else{
-    assert( pC->pseudoTable );
-    /* The record is the sole entry of a pseudo-table */
-    payloadSize = pC->nData;
-    zRec = pC->pData;
-    pC->cacheStatus = CACHE_STALE;
-    assert( payloadSize==0 || zRec!=0 );
-    nField = pC->nField;
-    pCrsr = 0;
+    /* Consider the row to be NULL */
+    u.an.payloadSize = 0;
   }
 
-  /* If payloadSize is 0, then just store a NULL */
-  if( payloadSize==0 ){
-    assert( pDest->flags&MEM_Null );
+  /* If u.an.payloadSize is 0, then just store a NULL.  This can happen because of
+  ** nullRow or because of a corrupt database. */
+  if( u.an.payloadSize==0 ){
+    MemSetTypeFlag(u.an.pDest, MEM_Null);
     goto op_column_out;
   }
-  if( payloadSize>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+  assert( db->aLimit[SQLITE_LIMIT_LENGTH]>=0 );
+  if( u.an.payloadSize > (u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
     goto too_big;
   }
 
-  assert( p2<nField );
+  u.an.nField = u.an.pC->nField;
+  assert( u.an.p2<u.an.nField );
 
   /* Read and parse the table header.  Store the results of the parse
   ** into the record header cache fields of the cursor.
   */
-  aType = pC->aType;
-  if( pC->cacheStatus==p->cacheCtr ){
-    aOffset = pC->aOffset;
+  u.an.aType = u.an.pC->aType;
+  if( u.an.pC->cacheStatus==p->cacheCtr ){
+    u.an.aOffset = u.an.pC->aOffset;
   }else{
-    u8 *zIdx;        /* Index into header */
-    u8 *zEndHdr;     /* Pointer to first byte after the header */
-    int offset;      /* Offset into the data */
-    int szHdrSz;     /* Size of the header size field at start of record */
-    int avail = 0;   /* Number of bytes of available data */
-
-    assert(aType);
-    pC->aOffset = aOffset = &aType[nField];
-    pC->payloadSize = payloadSize;
-    pC->cacheStatus = p->cacheCtr;
+    assert(u.an.aType);
+    u.an.avail = 0;
+    u.an.pC->aOffset = u.an.aOffset = &u.an.aType[u.an.nField];
+    u.an.pC->payloadSize = u.an.payloadSize;
+    u.an.pC->cacheStatus = p->cacheCtr;
 
     /* Figure out how many bytes are in the header */
-    if( zRec ){
-      zData = zRec;
+    if( u.an.zRec ){
+      u.an.zData = u.an.zRec;
     }else{
-      if( pC->isIndex ){
-        zData = (char*)sqlite3BtreeKeyFetch(pCrsr, &avail);
+      if( u.an.pC->isIndex ){
+        u.an.zData = (char*)sqlite3BtreeKeyFetch(u.an.pCrsr, &u.an.avail);
       }else{
-        zData = (char*)sqlite3BtreeDataFetch(pCrsr, &avail);
+        u.an.zData = (char*)sqlite3BtreeDataFetch(u.an.pCrsr, &u.an.avail);
       }
       /* If KeyFetch()/DataFetch() managed to get the entire payload,
-      ** save the payload in the pC->aRow cache.  That will save us from
+      ** save the payload in the u.an.pC->aRow cache.  That will save us from
       ** having to make additional calls to fetch the content portion of
       ** the record.
       */
-      if( avail>=payloadSize ){
-        zRec = zData;
-        pC->aRow = (u8*)zData;
+      assert( u.an.avail>=0 );
+      if( u.an.payloadSize <= (u32)u.an.avail ){
+        u.an.zRec = u.an.zData;
+        u.an.pC->aRow = (u8*)u.an.zData;
       }else{
-        pC->aRow = 0;
+        u.an.pC->aRow = 0;
       }
     }
-    /* The following assert is true in all cases accept when
+    /* The following assert is true in all cases except when
     ** the database file has been corrupted externally.
-    **    assert( zRec!=0 || avail>=payloadSize || avail>=9 ); */
-    szHdrSz = getVarint32((u8*)zData, offset);
+    **    assert( u.an.zRec!=0 || u.an.avail>=u.an.payloadSize || u.an.avail>=9 ); */
+    u.an.szHdr = getVarint32((u8*)u.an.zData, u.an.offset);
+
+    /* Make sure a corrupt database has not given us an oversize header.
+    ** Do this now to avoid an oversize memory allocation.
+    **
+    ** Type entries can be between 1 and 5 bytes each.  But 4 and 5 byte
+    ** types use so much data space that there can only be 4096 and 32 of
+    ** them, respectively.  So the maximum header length results from a
+    ** 3-byte type for each of the maximum of 32768 columns plus three
+    ** extra bytes for the header length itself.  32768*3 + 3 = 98307.
+    */
+    if( u.an.offset > 98307 ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto op_column_out;
+    }
+
+    /* Compute in u.an.len the number of bytes of data we need to read in order
+    ** to get u.an.nField type values.  u.an.offset is an upper bound on this.  But
+    ** u.an.nField might be significantly less than the true number of columns
+    ** in the table, and in that case, 5*u.an.nField+3 might be smaller than u.an.offset.
+    ** We want to minimize u.an.len in order to limit the size of the memory
+    ** allocation, especially if a corrupt database file has caused u.an.offset
+    ** to be oversized. Offset is limited to 98307 above.  But 98307 might
+    ** still exceed Robson memory allocation limits on some configurations.
+    ** On systems that cannot tolerate large memory allocations, u.an.nField*5+3
+    ** will likely be much smaller since u.an.nField will likely be less than
+    ** 20 or so.  This insures that Robson memory allocation limits are
+    ** not exceeded even for corrupt database files.
+    */
+    u.an.len = u.an.nField*5 + 3;
+    if( u.an.len > (int)u.an.offset ) u.an.len = (int)u.an.offset;
 
     /* The KeyFetch() or DataFetch() above are fast and will get the entire
     ** record header in most cases.  But they will fail to get the complete
@@ -50849,104 +65794,130 @@ case OP_Column: {
     ** in the B-Tree.  When that happens, use sqlite3VdbeMemFromBtree() to
     ** acquire the complete header text.
     */
-    if( !zRec && avail<offset ){
-      sMem.flags = 0;
-      sMem.db = 0;
-      rc = sqlite3VdbeMemFromBtree(pCrsr, 0, offset, pC->isIndex, &sMem);
+    if( !u.an.zRec && u.an.avail<u.an.len ){
+      u.an.sMem.flags = 0;
+      u.an.sMem.db = 0;
+      rc = sqlite3VdbeMemFromBtree(u.an.pCrsr, 0, u.an.len, u.an.pC->isIndex, &u.an.sMem);
       if( rc!=SQLITE_OK ){
         goto op_column_out;
       }
-      zData = sMem.z;
+      u.an.zData = u.an.sMem.z;
     }
-    zEndHdr = (u8 *)&zData[offset];
-    zIdx = (u8 *)&zData[szHdrSz];
+    u.an.zEndHdr = (u8 *)&u.an.zData[u.an.len];
+    u.an.zIdx = (u8 *)&u.an.zData[u.an.szHdr];
 
-    /* Scan the header and use it to fill in the aType[] and aOffset[]
-    ** arrays.  aType[i] will contain the type integer for the i-th
-    ** column and aOffset[i] will contain the offset from the beginning
-    ** of the record to the start of the data for the i-th column
+    /* Scan the header and use it to fill in the u.an.aType[] and u.an.aOffset[]
+    ** arrays.  u.an.aType[u.an.i] will contain the type integer for the u.an.i-th
+    ** column and u.an.aOffset[u.an.i] will contain the u.an.offset from the beginning
+    ** of the record to the start of the data for the u.an.i-th column
     */
-    for(i=0; i<nField; i++){
-      if( zIdx<zEndHdr ){
-        aOffset[i] = offset;
-        zIdx += getVarint32(zIdx, aType[i]);
-        offset += sqlite3VdbeSerialTypeLen(aType[i]);
+    for(u.an.i=0; u.an.i<u.an.nField; u.an.i++){
+      if( u.an.zIdx<u.an.zEndHdr ){
+        u.an.aOffset[u.an.i] = u.an.offset;
+        if( u.an.zIdx[0]<0x80 ){
+          u.an.t = u.an.zIdx[0];
+          u.an.zIdx++;
+        }else{
+          u.an.zIdx += sqlite3GetVarint32(u.an.zIdx, &u.an.t);
+        }
+        u.an.aType[u.an.i] = u.an.t;
+        u.an.szField = sqlite3VdbeSerialTypeLen(u.an.t);
+        u.an.offset += u.an.szField;
+        if( u.an.offset<u.an.szField ){  /* True if u.an.offset overflows */
+          u.an.zIdx = &u.an.zEndHdr[1];  /* Forces SQLITE_CORRUPT return below */
+          break;
+        }
       }else{
-        /* If i is less that nField, then there are less fields in this
+        /* If u.an.i is less that u.an.nField, then there are fewer fields in this
         ** record than SetNumColumns indicated there are columns in the
-        ** table. Set the offset for any extra columns not present in
-        ** the record to 0. This tells code below to store a NULL
-        ** instead of deserializing a value from the record.
+        ** table. Set the u.an.offset for any extra columns not present in
+        ** the record to 0. This tells code below to store the default value
+        ** for the column instead of deserializing a value from the record.
         */
-        aOffset[i] = 0;
+        u.an.aOffset[u.an.i] = 0;
       }
     }
-    sqlite3VdbeMemRelease(&sMem);
-    sMem.flags = MEM_Null;
+    sqlite3VdbeMemRelease(&u.an.sMem);
+    u.an.sMem.flags = MEM_Null;
 
     /* If we have read more header data than was contained in the header,
     ** or if the end of the last field appears to be past the end of the
     ** record, or if the end of the last field appears to be before the end
-    ** of the record (when all fields present), then we must be dealing 
+    ** of the record (when all fields present), then we must be dealing
     ** with a corrupt database.
     */
-    if( zIdx>zEndHdr || offset>payloadSize 
-     || (zIdx==zEndHdr && offset!=payloadSize) ){
+    if( (u.an.zIdx > u.an.zEndHdr) || (u.an.offset > u.an.payloadSize)
+         || (u.an.zIdx==u.an.zEndHdr && u.an.offset!=u.an.payloadSize) ){
       rc = SQLITE_CORRUPT_BKPT;
       goto op_column_out;
     }
   }
 
-  /* Get the column information. If aOffset[p2] is non-zero, then 
-  ** deserialize the value from the record. If aOffset[p2] is zero,
+  /* Get the column information. If u.an.aOffset[u.an.p2] is non-zero, then
+  ** deserialize the value from the record. If u.an.aOffset[u.an.p2] is zero,
   ** then there are not enough fields in the record to satisfy the
   ** request.  In this case, set the value NULL or to P4 if P4 is
   ** a pointer to a Mem object.
   */
-  if( aOffset[p2] ){
+  if( u.an.aOffset[u.an.p2] ){
     assert( rc==SQLITE_OK );
-    if( zRec ){
-      sqlite3VdbeMemReleaseExternal(pDest);
-      sqlite3VdbeSerialGet((u8 *)&zRec[aOffset[p2]], aType[p2], pDest);
+    if( u.an.zRec ){
+      /* This is the common case where the whole row fits on a single page */
+      VdbeMemRelease(u.an.pDest);
+      sqlite3VdbeSerialGet((u8 *)&u.an.zRec[u.an.aOffset[u.an.p2]], u.an.aType[u.an.p2], u.an.pDest);
     }else{
-      len = sqlite3VdbeSerialTypeLen(aType[p2]);
-      sqlite3VdbeMemMove(&sMem, pDest);
-      rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex, &sMem);
-      if( rc!=SQLITE_OK ){
-        goto op_column_out;
+      /* This branch happens only when the row overflows onto multiple pages */
+      u.an.t = u.an.aType[u.an.p2];
+      if( (pOp->p5 & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG))!=0
+       && ((u.an.t>=12 && (u.an.t&1)==0) || (pOp->p5 & OPFLAG_TYPEOFARG)!=0)
+      ){
+        /* Content is irrelevant for the typeof() function and for
+        ** the length(X) function if X is a blob.  So we might as well use
+        ** bogus content rather than reading content from disk.  NULL works
+        ** for text and blob and whatever is in the u.an.payloadSize64 variable
+        ** will work for everything else. */
+        u.an.zData = u.an.t<12 ? (char*)&u.an.payloadSize64 : 0;
+      }else{
+        u.an.len = sqlite3VdbeSerialTypeLen(u.an.t);
+        sqlite3VdbeMemMove(&u.an.sMem, u.an.pDest);
+        rc = sqlite3VdbeMemFromBtree(u.an.pCrsr, u.an.aOffset[u.an.p2], u.an.len,  u.an.pC->isIndex,
+                                     &u.an.sMem);
+        if( rc!=SQLITE_OK ){
+          goto op_column_out;
+        }
+        u.an.zData = u.an.sMem.z;
       }
-      zData = sMem.z;
-      sqlite3VdbeSerialGet((u8*)zData, aType[p2], pDest);
+      sqlite3VdbeSerialGet((u8*)u.an.zData, u.an.t, u.an.pDest);
     }
-    pDest->enc = encoding;
+    u.an.pDest->enc = encoding;
   }else{
     if( pOp->p4type==P4_MEM ){
-      sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static);
+      sqlite3VdbeMemShallowCopy(u.an.pDest, pOp->p4.pMem, MEM_Static);
     }else{
-      assert( pDest->flags&MEM_Null );
+      MemSetTypeFlag(u.an.pDest, MEM_Null);
     }
   }
 
   /* If we dynamically allocated space to hold the data (in the
   ** sqlite3VdbeMemFromBtree() call above) then transfer control of that
-  ** dynamically allocated space over to the pDest structure.
+  ** dynamically allocated space over to the u.an.pDest structure.
   ** This prevents a memory copy.
   */
-  if( sMem.zMalloc ){
-    assert( sMem.z==sMem.zMalloc );
-    assert( !(pDest->flags & MEM_Dyn) );
-    assert( !(pDest->flags & (MEM_Blob|MEM_Str)) || pDest->z==sMem.z );
-    pDest->flags &= ~(MEM_Ephem|MEM_Static);
-    pDest->flags |= MEM_Term;
-    pDest->z = sMem.z;
-    pDest->zMalloc = sMem.zMalloc;
+  if( u.an.sMem.zMalloc ){
+    assert( u.an.sMem.z==u.an.sMem.zMalloc );
+    assert( !(u.an.pDest->flags & MEM_Dyn) );
+    assert( !(u.an.pDest->flags & (MEM_Blob|MEM_Str)) || u.an.pDest->z==u.an.sMem.z );
+    u.an.pDest->flags &= ~(MEM_Ephem|MEM_Static);
+    u.an.pDest->flags |= MEM_Term;
+    u.an.pDest->z = u.an.sMem.z;
+    u.an.pDest->zMalloc = u.an.sMem.zMalloc;
   }
 
-  rc = sqlite3VdbeMemMakeWriteable(pDest);
+  rc = sqlite3VdbeMemMakeWriteable(u.an.pDest);
 
 op_column_out:
-  UPDATE_MAX_BLOBSIZE(pDest);
-  REGISTER_TRACE(pOp->p3, pDest);
+  UPDATE_MAX_BLOBSIZE(u.an.pDest);
+  REGISTER_TRACE(pOp->p3, u.an.pDest);
   break;
 }
 
@@ -50959,26 +65930,30 @@ op_column_out:
 ** memory cell in the range.
 */
 case OP_Affinity: {
-  char *zAffinity = pOp->p4.z;
-  Mem *pData0 = &p->aMem[pOp->p1];
-  Mem *pLast = &pData0[pOp->p2-1];
-  Mem *pRec;
+#if 0  /* local variables moved into u.ao */
+  const char *zAffinity;   /* The affinity to be applied */
+  char cAff;               /* A single character of affinity */
+#endif /* local variables moved into u.ao */
 
-  for(pRec=pData0; pRec<=pLast; pRec++){
-    ExpandBlob(pRec);
-    applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
+  u.ao.zAffinity = pOp->p4.z;
+  assert( u.ao.zAffinity!=0 );
+  assert( u.ao.zAffinity[pOp->p2]==0 );
+  pIn1 = &aMem[pOp->p1];
+  while( (u.ao.cAff = *(u.ao.zAffinity++))!=0 ){
+    assert( pIn1 <= &p->aMem[p->nMem] );
+    assert( memIsValid(pIn1) );
+    ExpandBlob(pIn1);
+    applyAffinity(pIn1, u.ao.cAff, encoding);
+    pIn1++;
   }
   break;
 }
 
 /* Opcode: MakeRecord P1 P2 P3 P4 *
 **
-** Convert P2 registers beginning with P1 into a single entry
-** suitable for use as a data record in a database table or as a key
-** in an index.  The details of the format are irrelevant as long as
-** the OP_Column opcode can decode the record later.
-** Refer to source code comments for the details of the record
-** format.
+** Convert P2 registers beginning with P1 into the [record format]
+** use as a data record in a database table or as a key
+** in an index.  The OP_Column opcode can decode the record later.
 **
 ** P4 may be a string that is P2 characters long.  The nth character of the
 ** string indicates the column affinity that should be used for the nth
@@ -50990,27 +65965,13 @@ case OP_Affinity: {
 ** If P4 is NULL then all index fields have the affinity NONE.
 */
 case OP_MakeRecord: {
-  /* Assuming the record contains N fields, the record format looks
-  ** like this:
-  **
-  ** ------------------------------------------------------------------------
-  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 | 
-  ** ------------------------------------------------------------------------
-  **
-  ** Data(0) is taken from register P1.  Data(1) comes from register P1+1
-  ** and so froth.
-  **
-  ** Each type field is a varint representing the serial type of the 
-  ** corresponding data element (see sqlite3VdbeSerialType()). The
-  ** hdr-size field is also a varint which is the offset from the beginning
-  ** of the record to data0.
-  */
+#if 0  /* local variables moved into u.ap */
   u8 *zNewRecord;        /* A buffer to hold the data for the new record */
   Mem *pRec;             /* The new record */
-  u64 nData = 0;         /* Number of bytes of data space */
-  int nHdr = 0;          /* Number of bytes of header space */
-  i64 nByte = 0;         /* Data space required for this record */
-  int nZero = 0;         /* Number of zero bytes at the end of the record */
+  u64 nData;             /* Number of bytes of data space */
+  int nHdr;              /* Number of bytes of header space */
+  i64 nByte;             /* Data space required for this record */
+  int nZero;             /* Number of zero bytes at the end of the record */
   int nVarint;           /* Number of bytes in a varint */
   u32 serial_type;       /* Type field */
   Mem *pData0;           /* First field to be combined into the record */
@@ -51019,78 +65980,101 @@ case OP_MakeRecord: {
   char *zAffinity;       /* The affinity string for the record */
   int file_format;       /* File format to use for encoding */
   int i;                 /* Space used in zNewRecord[] */
+  int len;               /* Length of a field */
+#endif /* local variables moved into u.ap */
 
-  nField = pOp->p1;
-  zAffinity = pOp->p4.z;
-  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=p->nMem );
-  pData0 = &p->aMem[nField];
-  nField = pOp->p2;
-  pLast = &pData0[nField-1];
-  file_format = p->minWriteFileFormat;
+  /* Assuming the record contains N fields, the record format looks
+  ** like this:
+  **
+  ** ------------------------------------------------------------------------
+  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 |
+  ** ------------------------------------------------------------------------
+  **
+  ** Data(0) is taken from register P1.  Data(1) comes from register P1+1
+  ** and so froth.
+  **
+  ** Each type field is a varint representing the serial type of the
+  ** corresponding data element (see sqlite3VdbeSerialType()). The
+  ** hdr-size field is also a varint which is the offset from the beginning
+  ** of the record to data0.
+  */
+  u.ap.nData = 0;         /* Number of bytes of data space */
+  u.ap.nHdr = 0;          /* Number of bytes of header space */
+  u.ap.nZero = 0;         /* Number of zero bytes at the end of the record */
+  u.ap.nField = pOp->p1;
+  u.ap.zAffinity = pOp->p4.z;
+  assert( u.ap.nField>0 && pOp->p2>0 && pOp->p2+u.ap.nField<=p->nMem+1 );
+  u.ap.pData0 = &aMem[u.ap.nField];
+  u.ap.nField = pOp->p2;
+  u.ap.pLast = &u.ap.pData0[u.ap.nField-1];
+  u.ap.file_format = p->minWriteFileFormat;
+
+  /* Identify the output register */
+  assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
+  pOut = &aMem[pOp->p3];
+  memAboutToChange(p, pOut);
 
   /* Loop through the elements that will make up the record to figure
   ** out how much space is required for the new record.
   */
-  for(pRec=pData0; pRec<=pLast; pRec++){
-    int len;
-    if( zAffinity ){
-      applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
+  for(u.ap.pRec=u.ap.pData0; u.ap.pRec<=u.ap.pLast; u.ap.pRec++){
+    assert( memIsValid(u.ap.pRec) );
+    if( u.ap.zAffinity ){
+      applyAffinity(u.ap.pRec, u.ap.zAffinity[u.ap.pRec-u.ap.pData0], encoding);
     }
-    if( pRec->flags&MEM_Zero && pRec->n>0 ){
-      sqlite3VdbeMemExpandBlob(pRec);
+    if( u.ap.pRec->flags&MEM_Zero && u.ap.pRec->n>0 ){
+      sqlite3VdbeMemExpandBlob(u.ap.pRec);
     }
-    serial_type = sqlite3VdbeSerialType(pRec, file_format);
-    len = sqlite3VdbeSerialTypeLen(serial_type);
-    nData += len;
-    nHdr += sqlite3VarintLen(serial_type);
-    if( pRec->flags & MEM_Zero ){
+    u.ap.serial_type = sqlite3VdbeSerialType(u.ap.pRec, u.ap.file_format);
+    u.ap.len = sqlite3VdbeSerialTypeLen(u.ap.serial_type);
+    u.ap.nData += u.ap.len;
+    u.ap.nHdr += sqlite3VarintLen(u.ap.serial_type);
+    if( u.ap.pRec->flags & MEM_Zero ){
       /* Only pure zero-filled BLOBs can be input to this Opcode.
       ** We do not allow blobs with a prefix and a zero-filled tail. */
-      nZero += pRec->u.nZero;
-    }else if( len ){
-      nZero = 0;
+      u.ap.nZero += u.ap.pRec->u.nZero;
+    }else if( u.ap.len ){
+      u.ap.nZero = 0;
     }
   }
 
   /* Add the initial header varint and total the size */
-  nHdr += nVarint = sqlite3VarintLen(nHdr);
-  if( nVarint<sqlite3VarintLen(nHdr) ){
-    nHdr++;
+  u.ap.nHdr += u.ap.nVarint = sqlite3VarintLen(u.ap.nHdr);
+  if( u.ap.nVarint<sqlite3VarintLen(u.ap.nHdr) ){
+    u.ap.nHdr++;
   }
-  nByte = nHdr+nData-nZero;
-  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+  u.ap.nByte = u.ap.nHdr+u.ap.nData-u.ap.nZero;
+  if( u.ap.nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
     goto too_big;
   }
 
-  /* Make sure the output register has a buffer large enough to store 
+  /* Make sure the output register has a buffer large enough to store
   ** the new record. The output register (pOp->p3) is not allowed to
   ** be one of the input registers (because the following call to
   ** sqlite3VdbeMemGrow() could clobber the value before it is used).
   */
-  assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
-  pOut = &p->aMem[pOp->p3];
-  if( sqlite3VdbeMemGrow(pOut, (int)nByte, 0) ){
+  if( sqlite3VdbeMemGrow(pOut, (int)u.ap.nByte, 0) ){
     goto no_mem;
   }
-  zNewRecord = (u8 *)pOut->z;
+  u.ap.zNewRecord = (u8 *)pOut->z;
 
   /* Write the record */
-  i = putVarint32(zNewRecord, nHdr);
-  for(pRec=pData0; pRec<=pLast; pRec++){
-    serial_type = sqlite3VdbeSerialType(pRec, file_format);
-    i += putVarint32(&zNewRecord[i], serial_type);      /* serial type */
+  u.ap.i = putVarint32(u.ap.zNewRecord, u.ap.nHdr);
+  for(u.ap.pRec=u.ap.pData0; u.ap.pRec<=u.ap.pLast; u.ap.pRec++){
+    u.ap.serial_type = sqlite3VdbeSerialType(u.ap.pRec, u.ap.file_format);
+    u.ap.i += putVarint32(&u.ap.zNewRecord[u.ap.i], u.ap.serial_type);      /* serial type */
   }
-  for(pRec=pData0; pRec<=pLast; pRec++){  /* serial data */
-    i += sqlite3VdbeSerialPut(&zNewRecord[i], (int)(nByte-i), pRec,file_format);
+  for(u.ap.pRec=u.ap.pData0; u.ap.pRec<=u.ap.pLast; u.ap.pRec++){  /* serial data */
+    u.ap.i += sqlite3VdbeSerialPut(&u.ap.zNewRecord[u.ap.i], (int)(u.ap.nByte-u.ap.i), u.ap.pRec,u.ap.file_format);
   }
-  assert( i==nByte );
+  assert( u.ap.i==u.ap.nByte );
 
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  pOut->n = (int)nByte;
+  pOut->n = (int)u.ap.nByte;
   pOut->flags = MEM_Blob | MEM_Dyn;
   pOut->xDel = 0;
-  if( nZero ){
-    pOut->u.nZero = nZero;
+  if( u.ap.nZero ){
+    pOut->u.nZero = u.ap.nZero;
     pOut->flags |= MEM_Zero;
   }
   pOut->enc = SQLITE_UTF8;  /* In case the blob is ever converted to text */
@@ -51099,44 +66083,28 @@ case OP_MakeRecord: {
   break;
 }
 
-/* Opcode: Statement P1 * * * *
+/* Opcode: Count P1 P2 * * *
 **
-** Begin an individual statement transaction which is part of a larger
-** transaction.  This is needed so that the statement
-** can be rolled back after an error without having to roll back the
-** entire transaction.  The statement transaction will automatically
-** commit when the VDBE halts.
-**
-** If the database connection is currently in autocommit mode (that 
-** is to say, if it is in between BEGIN and COMMIT)
-** and if there are no other active statements on the same database
-** connection, then this operation is a no-op.  No statement transaction
-** is needed since any error can use the normal ROLLBACK process to
-** undo changes.
-**
-** If a statement transaction is started, then a statement journal file
-** will be allocated and initialized.
-**
-** The statement is begun on the database file with index P1.  The main
-** database file has an index of 0 and the file used for temporary tables
-** has an index of 1.
+** Store the number of entries (an integer value) in the table or index 
+** opened by cursor P1 in register P2
 */
-case OP_Statement: {
-  if( db->autoCommit==0 || db->activeVdbeCnt>1 ){
-    int i = pOp->p1;
-    Btree *pBt;
-    assert( i>=0 && i<db->nDb );
-    assert( db->aDb[i].pBt!=0 );
-    pBt = db->aDb[i].pBt;
-    assert( sqlite3BtreeIsInTrans(pBt) );
-    assert( (p->btreeMask & (1<<i))!=0 );
-    if( !sqlite3BtreeIsInStmt(pBt) ){
-      rc = sqlite3BtreeBeginStmt(pBt);
-      p->openedStatement = 1;
-    }
+#ifndef SQLITE_OMIT_BTREECOUNT
+case OP_Count: {         /* out2-prerelease */
+#if 0  /* local variables moved into u.aq */
+  i64 nEntry;
+  BtCursor *pCrsr;
+#endif /* local variables moved into u.aq */
+
+  u.aq.pCrsr = p->apCsr[pOp->p1]->pCursor;
+  if( ALWAYS(u.aq.pCrsr) ){
+    rc = sqlite3BtreeCount(u.aq.pCrsr, &u.aq.nEntry);
+  }else{
+    u.aq.nEntry = 0;
   }
+  pOut->u.i = u.aq.nEntry;
   break;
 }
+#endif
 
 /* Opcode: Savepoint P1 * * P4 *
 **
@@ -51145,35 +66113,56 @@ case OP_Statement: {
 ** existing savepoint, P1==1, or to rollback an existing savepoint P1==2.
 */
 case OP_Savepoint: {
-  int p1 = pOp->p1;
-  char *zName = pOp->p4.z;         /* Name of savepoint */
+#if 0  /* local variables moved into u.ar */
+  int p1;                         /* Value of P1 operand */
+  char *zName;                    /* Name of savepoint */
+  int nName;
+  Savepoint *pNew;
+  Savepoint *pSavepoint;
+  Savepoint *pTmp;
+  int iSavepoint;
+  int ii;
+#endif /* local variables moved into u.ar */
 
-  /* Assert that the p1 parameter is valid. Also that if there is no open
-  ** transaction, then there cannot be any savepoints. 
+  u.ar.p1 = pOp->p1;
+  u.ar.zName = pOp->p4.z;
+
+  /* Assert that the u.ar.p1 parameter is valid. Also that if there is no open
+  ** transaction, then there cannot be any savepoints.
   */
   assert( db->pSavepoint==0 || db->autoCommit==0 );
-  assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
+  assert( u.ar.p1==SAVEPOINT_BEGIN||u.ar.p1==SAVEPOINT_RELEASE||u.ar.p1==SAVEPOINT_ROLLBACK );
   assert( db->pSavepoint || db->isTransactionSavepoint==0 );
   assert( checkSavepointCount(db) );
 
-  if( p1==SAVEPOINT_BEGIN ){
+  if( u.ar.p1==SAVEPOINT_BEGIN ){
     if( db->writeVdbeCnt>0 ){
-      /* A new savepoint cannot be created if there are active write 
+      /* A new savepoint cannot be created if there are active write
       ** statements (i.e. open read/write incremental blob handles).
       */
       sqlite3SetString(&p->zErrMsg, db, "cannot open savepoint - "
         "SQL statements in progress");
       rc = SQLITE_BUSY;
     }else{
-      int nName = sqlite3Strlen30(zName);
-      Savepoint *pNew;
+      u.ar.nName = sqlite3Strlen30(u.ar.zName);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* This call is Ok even if this savepoint is actually a transaction
+      ** savepoint (and therefore should not prompt xSavepoint()) callbacks.
+      ** If this is a transaction savepoint being opened, it is guaranteed
+      ** that the db->aVTrans[] array is empty.  */
+      assert( db->autoCommit==0 || db->nVTrans==0 );
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN,
+                                db->nStatement+db->nSavepoint);
+      if( rc!=SQLITE_OK ) goto abort_due_to_error;
+#endif
 
       /* Create a new savepoint structure. */
-      pNew = sqlite3DbMallocRaw(db, sizeof(Savepoint)+nName+1);
-      if( pNew ){
-        pNew->zName = (char *)&pNew[1];
-        memcpy(pNew->zName, zName, nName+1);
-    
+      u.ar.pNew = sqlite3DbMallocRaw(db, sizeof(Savepoint)+u.ar.nName+1);
+      if( u.ar.pNew ){
+        u.ar.pNew->zName = (char *)&u.ar.pNew[1];
+        memcpy(u.ar.pNew->zName, u.ar.zName, u.ar.nName+1);
+
         /* If there is no open transaction, then mark this as a special
         ** "transaction savepoint". */
         if( db->autoCommit ){
@@ -51181,49 +66170,48 @@ case OP_Savepoint: {
           db->isTransactionSavepoint = 1;
         }else{
           db->nSavepoint++;
-	}
-    
+        }
+
         /* Link the new savepoint into the database handle's list. */
-        pNew->pNext = db->pSavepoint;
-        db->pSavepoint = pNew;
+        u.ar.pNew->pNext = db->pSavepoint;
+        db->pSavepoint = u.ar.pNew;
+        u.ar.pNew->nDeferredCons = db->nDeferredCons;
       }
     }
   }else{
-    Savepoint *pSavepoint;
-    int iSavepoint = 0;
+    u.ar.iSavepoint = 0;
 
     /* Find the named savepoint. If there is no such savepoint, then an
     ** an error is returned to the user.  */
     for(
-      pSavepoint=db->pSavepoint; 
-      pSavepoint && sqlite3StrICmp(pSavepoint->zName, zName);
-      pSavepoint=pSavepoint->pNext
+      u.ar.pSavepoint = db->pSavepoint;
+      u.ar.pSavepoint && sqlite3StrICmp(u.ar.pSavepoint->zName, u.ar.zName);
+      u.ar.pSavepoint = u.ar.pSavepoint->pNext
     ){
-      iSavepoint++;
+      u.ar.iSavepoint++;
     }
-    if( !pSavepoint ){
-      sqlite3SetString(&p->zErrMsg, db, "no such savepoint: %s", zName);
+    if( !u.ar.pSavepoint ){
+      sqlite3SetString(&p->zErrMsg, db, "no such savepoint: %s", u.ar.zName);
       rc = SQLITE_ERROR;
-    }else if( 
-        db->writeVdbeCnt>0 || (p1==SAVEPOINT_ROLLBACK && db->activeVdbeCnt>1) 
-    ){
-      /* It is not possible to release (commit) a savepoint if there are 
-      ** active write statements. It is not possible to rollback a savepoint
-      ** if there are any active statements at all.
+    }else if( db->writeVdbeCnt>0 && u.ar.p1==SAVEPOINT_RELEASE ){
+      /* It is not possible to release (commit) a savepoint if there are
+      ** active write statements.
       */
-      sqlite3SetString(&p->zErrMsg, db, 
-        "cannot %s savepoint - SQL statements in progress",
-        (p1==SAVEPOINT_ROLLBACK ? "rollback": "release")
+      sqlite3SetString(&p->zErrMsg, db,
+        "cannot release savepoint - SQL statements in progress"
       );
       rc = SQLITE_BUSY;
     }else{
 
       /* Determine whether or not this is a transaction savepoint. If so,
-      ** and this is a RELEASE command, then the current transaction 
-      ** is committed. 
+      ** and this is a RELEASE command, then the current transaction
+      ** is committed.
       */
-      int isTransaction = pSavepoint->pNext==0 && db->isTransactionSavepoint;
-      if( isTransaction && p1==SAVEPOINT_RELEASE ){
+      int isTransaction = u.ar.pSavepoint->pNext==0 && db->isTransactionSavepoint;
+      if( isTransaction && u.ar.p1==SAVEPOINT_RELEASE ){
+        if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
+          goto vdbe_return;
+        }
         db->autoCommit = 1;
         if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
           p->pc = pc;
@@ -51234,37 +66222,52 @@ case OP_Savepoint: {
         db->isTransactionSavepoint = 0;
         rc = p->rc;
       }else{
-        int ii;
-        iSavepoint = db->nSavepoint - iSavepoint - 1;
-        for(ii=0; ii<db->nDb; ii++){
-          rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
+        u.ar.iSavepoint = db->nSavepoint - u.ar.iSavepoint - 1;
+        if( u.ar.p1==SAVEPOINT_ROLLBACK ){
+          for(u.ar.ii=0; u.ar.ii<db->nDb; u.ar.ii++){
+            sqlite3BtreeTripAllCursors(db->aDb[u.ar.ii].pBt, SQLITE_ABORT);
+          }
+        }
+        for(u.ar.ii=0; u.ar.ii<db->nDb; u.ar.ii++){
+          rc = sqlite3BtreeSavepoint(db->aDb[u.ar.ii].pBt, u.ar.p1, u.ar.iSavepoint);
           if( rc!=SQLITE_OK ){
             goto abort_due_to_error;
-	  }
+          }
         }
-        if( p1==SAVEPOINT_ROLLBACK && (db->flags&SQLITE_InternChanges)!=0 ){
+        if( u.ar.p1==SAVEPOINT_ROLLBACK && (db->flags&SQLITE_InternChanges)!=0 ){
           sqlite3ExpirePreparedStatements(db);
-          sqlite3ResetInternalSchema(db, 0);
+          sqlite3ResetAllSchemasOfConnection(db);
+          db->flags = (db->flags | SQLITE_InternChanges);
         }
       }
-  
-      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
+
+      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all
       ** savepoints nested inside of the savepoint being operated on. */
-      while( db->pSavepoint!=pSavepoint ){
-        Savepoint *pTmp = db->pSavepoint;
-        db->pSavepoint = pTmp->pNext;
-        sqlite3DbFree(db, pTmp);
+      while( db->pSavepoint!=u.ar.pSavepoint ){
+        u.ar.pTmp = db->pSavepoint;
+        db->pSavepoint = u.ar.pTmp->pNext;
+        sqlite3DbFree(db, u.ar.pTmp);
         db->nSavepoint--;
       }
 
-      /* If it is a RELEASE, then destroy the savepoint being operated on too */
-      if( p1==SAVEPOINT_RELEASE ){
-        assert( pSavepoint==db->pSavepoint );
-        db->pSavepoint = pSavepoint->pNext;
-        sqlite3DbFree(db, pSavepoint);
+      /* If it is a RELEASE, then destroy the savepoint being operated on
+      ** too. If it is a ROLLBACK TO, then set the number of deferred
+      ** constraint violations present in the database to the value stored
+      ** when the savepoint was created.  */
+      if( u.ar.p1==SAVEPOINT_RELEASE ){
+        assert( u.ar.pSavepoint==db->pSavepoint );
+        db->pSavepoint = u.ar.pSavepoint->pNext;
+        sqlite3DbFree(db, u.ar.pSavepoint);
         if( !isTransaction ){
           db->nSavepoint--;
         }
+      }else{
+        db->nDeferredCons = u.ar.pSavepoint->nDeferredCons;
+      }
+
+      if( !isTransaction ){
+        rc = sqlite3VtabSavepoint(db, u.ar.p1, u.ar.iSavepoint);
+        if( rc!=SQLITE_OK ) goto abort_due_to_error;
       }
     }
   }
@@ -51276,49 +66279,60 @@ case OP_Savepoint: {
 **
 ** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
 ** back any currently active btree transactions. If there are any active
-** VMs (apart from this one), then the COMMIT or ROLLBACK statement fails.
+** VMs (apart from this one), then a ROLLBACK fails.  A COMMIT fails if
+** there are active writing VMs or active VMs that use shared cache.
 **
 ** This instruction causes the VM to halt.
 */
 case OP_AutoCommit: {
-  int desiredAutoCommit = pOp->p1;
-  int rollback = pOp->p2;
-  int turnOnAC = desiredAutoCommit && !db->autoCommit;
-
-  assert( desiredAutoCommit==1 || desiredAutoCommit==0 );
-  assert( desiredAutoCommit==1 || rollback==0 );
+#if 0  /* local variables moved into u.as */
+  int desiredAutoCommit;
+  int iRollback;
+  int turnOnAC;
+#endif /* local variables moved into u.as */
 
+  u.as.desiredAutoCommit = pOp->p1;
+  u.as.iRollback = pOp->p2;
+  u.as.turnOnAC = u.as.desiredAutoCommit && !db->autoCommit;
+  assert( u.as.desiredAutoCommit==1 || u.as.desiredAutoCommit==0 );
+  assert( u.as.desiredAutoCommit==1 || u.as.iRollback==0 );
   assert( db->activeVdbeCnt>0 );  /* At least this one VM is active */
 
-  if( turnOnAC && rollback && db->activeVdbeCnt>1 ){
+#if 0
+  if( u.as.turnOnAC && u.as.iRollback && db->activeVdbeCnt>1 ){
     /* If this instruction implements a ROLLBACK and other VMs are
     ** still running, and a transaction is active, return an error indicating
-    ** that the other VMs must complete first. 
+    ** that the other VMs must complete first.
     */
     sqlite3SetString(&p->zErrMsg, db, "cannot rollback transaction - "
         "SQL statements in progress");
     rc = SQLITE_BUSY;
-  }else if( turnOnAC && !rollback && db->writeVdbeCnt>1 ){
+  }else
+#endif
+  if( u.as.turnOnAC && !u.as.iRollback && db->writeVdbeCnt>0 ){
     /* If this instruction implements a COMMIT and other VMs are writing
-    ** return an error indicating that the other VMs must complete first. 
+    ** return an error indicating that the other VMs must complete first.
     */
     sqlite3SetString(&p->zErrMsg, db, "cannot commit transaction - "
         "SQL statements in progress");
     rc = SQLITE_BUSY;
-  }else if( desiredAutoCommit!=db->autoCommit ){
-    if( rollback ){
-      assert( desiredAutoCommit==1 );
-      sqlite3RollbackAll(db);
+  }else if( u.as.desiredAutoCommit!=db->autoCommit ){
+    if( u.as.iRollback ){
+      assert( u.as.desiredAutoCommit==1 );
+      sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
       db->autoCommit = 1;
+    }else if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
+      goto vdbe_return;
     }else{
-      db->autoCommit = (u8)desiredAutoCommit;
+      db->autoCommit = (u8)u.as.desiredAutoCommit;
       if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
         p->pc = pc;
-        db->autoCommit = (u8)(1-desiredAutoCommit);
+        db->autoCommit = (u8)(1-u.as.desiredAutoCommit);
         p->rc = rc = SQLITE_BUSY;
         goto vdbe_return;
       }
     }
+    assert( db->nStatement==0 );
     sqlite3CloseSavepoints(db);
     if( p->rc==SQLITE_OK ){
       rc = SQLITE_DONE;
@@ -51328,10 +66342,10 @@ case OP_AutoCommit: {
     goto vdbe_return;
   }else{
     sqlite3SetString(&p->zErrMsg, db,
-        (!desiredAutoCommit)?"cannot start a transaction within a transaction":(
-        (rollback)?"cannot rollback - no transaction is active":
+        (!u.as.desiredAutoCommit)?"cannot start a transaction within a transaction":(
+        (u.as.iRollback)?"cannot rollback - no transaction is active":
                    "cannot commit - no transaction is active"));
-         
+
     rc = SQLITE_ERROR;
   }
   break;
@@ -51356,26 +66370,58 @@ case OP_AutoCommit: {
 ** database.  If P2 is 2 or greater then an EXCLUSIVE lock is also obtained
 ** on the file.
 **
+** If a write-transaction is started and the Vdbe.usesStmtJournal flag is
+** true (this flag is set if the Vdbe may modify more than one row and may
+** throw an ABORT exception), a statement transaction may also be opened.
+** More specifically, a statement transaction is opened iff the database
+** connection is currently not in autocommit mode, or if there are other
+** active statements. A statement transaction allows the changes made by this
+** VDBE to be rolled back after an error without having to roll back the
+** entire transaction. If no error is encountered, the statement transaction
+** will automatically commit when the VDBE halts.
+**
 ** If P2 is zero, then a read-lock is obtained on the database file.
 */
 case OP_Transaction: {
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.at */
   Btree *pBt;
+#endif /* local variables moved into u.at */
 
-  assert( i>=0 && i<db->nDb );
-  assert( (p->btreeMask & (1<<i))!=0 );
-  pBt = db->aDb[i].pBt;
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
+  u.at.pBt = db->aDb[pOp->p1].pBt;
 
-  if( pBt ){
-    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);
+  if( u.at.pBt ){
+    rc = sqlite3BtreeBeginTrans(u.at.pBt, pOp->p2);
     if( rc==SQLITE_BUSY ){
       p->pc = pc;
       p->rc = rc = SQLITE_BUSY;
       goto vdbe_return;
     }
-    if( rc!=SQLITE_OK && rc!=SQLITE_READONLY /* && rc!=SQLITE_BUSY */ ){
+    if( rc!=SQLITE_OK ){
       goto abort_due_to_error;
     }
+
+    if( pOp->p2 && p->usesStmtJournal
+     && (db->autoCommit==0 || db->activeVdbeCnt>1)
+    ){
+      assert( sqlite3BtreeIsInTrans(u.at.pBt) );
+      if( p->iStatement==0 ){
+        assert( db->nStatement>=0 && db->nSavepoint>=0 );
+        db->nStatement++;
+        p->iStatement = db->nSavepoint + db->nStatement;
+      }
+
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN, p->iStatement-1);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3BtreeBeginStmt(u.at.pBt, p->iStatement);
+      }
+
+      /* Store the current value of the database handles deferred constraint
+      ** counter. If the statement transaction needs to be rolled back,
+      ** the value of this counter needs to be restored too.  */
+      p->nStmtDefCons = db->nDeferredCons;
+    }
   }
   break;
 }
@@ -51383,87 +66429,81 @@ case OP_Transaction: {
 /* Opcode: ReadCookie P1 P2 P3 * *
 **
 ** Read cookie number P3 from database P1 and write it into register P2.
-** P3==0 is the schema version.  P3==1 is the database format.
-** P3==2 is the recommended pager cache size, and so forth.  P1==0 is
+** P3==1 is the schema version.  P3==2 is the database format.
+** P3==3 is the recommended pager cache size, and so forth.  P1==0 is
 ** the main database file and P1==1 is the database file used to store
 ** temporary tables.
 **
-** If P1 is negative, then this is a request to read the size of a
-** databases free-list. P3 must be set to 1 in this case. The actual
-** database accessed is ((P1+1)*-1). For example, a P1 parameter of -1
-** corresponds to database 0 ("main"), a P1 of -2 is database 1 ("temp").
-**
 ** There must be a read-lock on the database (either a transaction
 ** must be started or there must be an open cursor) before
 ** executing this instruction.
 */
 case OP_ReadCookie: {               /* out2-prerelease */
+#if 0  /* local variables moved into u.au */
   int iMeta;
-  int iDb = pOp->p1;
-  int iCookie = pOp->p3;
+  int iDb;
+  int iCookie;
+#endif /* local variables moved into u.au */
 
+  u.au.iDb = pOp->p1;
+  u.au.iCookie = pOp->p3;
   assert( pOp->p3<SQLITE_N_BTREE_META );
-  if( iDb<0 ){
-    iDb = (-1*(iDb+1));
-    iCookie *= -1;
-  }
-  assert( iDb>=0 && iDb<db->nDb );
-  assert( db->aDb[iDb].pBt!=0 );
-  assert( (p->btreeMask & (1<<iDb))!=0 );
-  /* The indexing of meta values at the schema layer is off by one from
-  ** the indexing in the btree layer.  The btree considers meta[0] to
-  ** be the number of free pages in the database (a read-only value)
-  ** and meta[1] to be the schema cookie.  The schema layer considers
-  ** meta[1] to be the schema cookie.  So we have to shift the index
-  ** by one in the following statement.
-  */
-  rc = sqlite3BtreeGetMeta(db->aDb[iDb].pBt, 1 + iCookie, (u32 *)&iMeta);
-  pOut->u.i = iMeta;
-  MemSetTypeFlag(pOut, MEM_Int);
+  assert( u.au.iDb>=0 && u.au.iDb<db->nDb );
+  assert( db->aDb[u.au.iDb].pBt!=0 );
+  assert( (p->btreeMask & (((yDbMask)1)<<u.au.iDb))!=0 );
+
+  sqlite3BtreeGetMeta(db->aDb[u.au.iDb].pBt, u.au.iCookie, (u32 *)&u.au.iMeta);
+  pOut->u.i = u.au.iMeta;
   break;
 }
 
 /* Opcode: SetCookie P1 P2 P3 * *
 **
 ** Write the content of register P3 (interpreted as an integer)
-** into cookie number P2 of database P1.
-** P2==0 is the schema version.  P2==1 is the database format.
-** P2==2 is the recommended pager cache size, and so forth.  P1==0 is
-** the main database file and P1==1 is the database file used to store
-** temporary tables.
+** into cookie number P2 of database P1.  P2==1 is the schema version.  
+** P2==2 is the database format. P2==3 is the recommended pager cache 
+** size, and so forth.  P1==0 is the main database file and P1==1 is the 
+** database file used to store temporary tables.
 **
 ** A transaction must be started before executing this opcode.
 */
 case OP_SetCookie: {       /* in3 */
+#if 0  /* local variables moved into u.av */
   Db *pDb;
+#endif /* local variables moved into u.av */
   assert( pOp->p2<SQLITE_N_BTREE_META );
   assert( pOp->p1>=0 && pOp->p1<db->nDb );
-  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
-  pDb = &db->aDb[pOp->p1];
-  assert( pDb->pBt!=0 );
+  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
+  u.av.pDb = &db->aDb[pOp->p1];
+  assert( u.av.pDb->pBt!=0 );
+  assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
+  pIn3 = &aMem[pOp->p3];
   sqlite3VdbeMemIntegerify(pIn3);
   /* See note about index shifting on OP_ReadCookie */
-  rc = sqlite3BtreeUpdateMeta(pDb->pBt, 1+pOp->p2, (int)pIn3->u.i);
-  if( pOp->p2==0 ){
+  rc = sqlite3BtreeUpdateMeta(u.av.pDb->pBt, pOp->p2, (int)pIn3->u.i);
+  if( pOp->p2==BTREE_SCHEMA_VERSION ){
     /* When the schema cookie changes, record the new cookie internally */
-    pDb->pSchema->schema_cookie = (int)pIn3->u.i;
+    u.av.pDb->pSchema->schema_cookie = (int)pIn3->u.i;
     db->flags |= SQLITE_InternChanges;
-  }else if( pOp->p2==1 ){
+  }else if( pOp->p2==BTREE_FILE_FORMAT ){
     /* Record changes in the file format */
-    pDb->pSchema->file_format = (u8)pIn3->u.i;
+    u.av.pDb->pSchema->file_format = (u8)pIn3->u.i;
   }
   if( pOp->p1==1 ){
     /* Invalidate all prepared statements whenever the TEMP database
     ** schema is changed.  Ticket #1644 */
     sqlite3ExpirePreparedStatements(db);
+    p->expired = 0;
   }
   break;
 }
 
-/* Opcode: VerifyCookie P1 P2 *
+/* Opcode: VerifyCookie P1 P2 P3 * *
 **
 ** Check the value of global database parameter number 0 (the
-** schema version) and make sure it is equal to P2.  
+** schema version) and make sure it is equal to P2 and that the
+** generation counter on the local schema parse equals P3.
+**
 ** P1 is the database number which is 0 for the main database file
 ** and 1 for the file holding temporary tables and some higher number
 ** for auxiliary databases.
@@ -51477,21 +66517,26 @@ case OP_SetCookie: {       /* in3 */
 ** invoked.
 */
 case OP_VerifyCookie: {
+#if 0  /* local variables moved into u.aw */
   int iMeta;
+  int iGen;
   Btree *pBt;
+#endif /* local variables moved into u.aw */
+
   assert( pOp->p1>=0 && pOp->p1<db->nDb );
-  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
-  pBt = db->aDb[pOp->p1].pBt;
-  if( pBt ){
-    rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&iMeta);
+  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
+  assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
+  u.aw.pBt = db->aDb[pOp->p1].pBt;
+  if( u.aw.pBt ){
+    sqlite3BtreeGetMeta(u.aw.pBt, BTREE_SCHEMA_VERSION, (u32 *)&u.aw.iMeta);
+    u.aw.iGen = db->aDb[pOp->p1].pSchema->iGeneration;
   }else{
-    rc = SQLITE_OK;
-    iMeta = 0;
+    u.aw.iGen = u.aw.iMeta = 0;
   }
-  if( rc==SQLITE_OK && iMeta!=pOp->p2 ){
+  if( u.aw.iMeta!=pOp->p2 || u.aw.iGen!=pOp->p3 ){
     sqlite3DbFree(db, p->zErrMsg);
     p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
-    /* If the schema-cookie from the database file matches the cookie 
+    /* If the schema-cookie from the database file matches the cookie
     ** stored with the in-memory representation of the schema, do
     ** not reload the schema from the database file.
     **
@@ -51501,14 +66546,14 @@ case OP_VerifyCookie: {
     ** prepared queries. If such a query is out-of-date, we do not want to
     ** discard the database schema, as the user code implementing the
     ** v-table would have to be ready for the sqlite3_vtab structure itself
-    ** to be invalidated whenever sqlite3_step() is called from within 
+    ** to be invalidated whenever sqlite3_step() is called from within
     ** a v-table method.
     */
-    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
-      sqlite3ResetInternalSchema(db, pOp->p1);
+    if( db->aDb[pOp->p1].pSchema->schema_cookie!=u.aw.iMeta ){
+      sqlite3ResetOneSchema(db, pOp->p1);
     }
 
-    sqlite3ExpirePreparedStatements(db);
+    p->expired = 1;
     rc = SQLITE_SCHEMA;
   }
   break;
@@ -51536,9 +66581,11 @@ case OP_VerifyCookie: {
 ** to get a read lock but fails, the script terminates with an
 ** SQLITE_BUSY error code.
 **
-** The P4 value is a pointer to a KeyInfo structure that defines the
-** content and collating sequence of indices.  P4 is NULL for cursors
-** that are not pointing to indices.
+** The P4 value may be either an integer (P4_INT32) or a pointer to
+** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo 
+** structure, then said structure defines the content and collating 
+** sequence of the index being opened. Otherwise, if P4 is an integer 
+** value, it is set to the number of columns in the table.
 **
 ** See also OpenWrite.
 */
@@ -51548,9 +66595,12 @@ case OP_VerifyCookie: {
 ** page is P2.  Or if P5!=0 use the content of register P2 to find the
 ** root page.
 **
-** The P4 value is a pointer to a KeyInfo structure that defines the
-** content and collating sequence of indices.  P4 is NULL for cursors
-** that are not pointing to indices.
+** The P4 value may be either an integer (P4_INT32) or a pointer to
+** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo 
+** structure, then said structure defines the content and collating 
+** sequence of the index being opened. Otherwise, if P4 is an integer 
+** value, it is set to the number of columns in the table, or to the
+** largest index of any column of the table that is actually used.
 **
 ** This instruction works just like OpenRead except that it opens the cursor
 ** in read/write mode.  For a given table, there can be one or more read-only
@@ -51560,102 +66610,98 @@ case OP_VerifyCookie: {
 */
 case OP_OpenRead:
 case OP_OpenWrite: {
-  int i = pOp->p1;
-  int p2 = pOp->p2;
-  int iDb = pOp->p3;
+#if 0  /* local variables moved into u.ax */
+  int nField;
+  KeyInfo *pKeyInfo;
+  int p2;
+  int iDb;
   int wrFlag;
   Btree *pX;
   VdbeCursor *pCur;
   Db *pDb;
-  
-  assert( iDb>=0 && iDb<db->nDb );
-  assert( (p->btreeMask & (1<<iDb))!=0 );
-  pDb = &db->aDb[iDb];
-  pX = pDb->pBt;
-  assert( pX!=0 );
+#endif /* local variables moved into u.ax */
+
+  assert( (pOp->p5&(OPFLAG_P2ISREG|OPFLAG_BULKCSR))==pOp->p5 );
+  assert( pOp->opcode==OP_OpenWrite || pOp->p5==0 );
+
+  if( p->expired ){
+    rc = SQLITE_ABORT;
+    break;
+  }
+
+  u.ax.nField = 0;
+  u.ax.pKeyInfo = 0;
+  u.ax.p2 = pOp->p2;
+  u.ax.iDb = pOp->p3;
+  assert( u.ax.iDb>=0 && u.ax.iDb<db->nDb );
+  assert( (p->btreeMask & (((yDbMask)1)<<u.ax.iDb))!=0 );
+  u.ax.pDb = &db->aDb[u.ax.iDb];
+  u.ax.pX = u.ax.pDb->pBt;
+  assert( u.ax.pX!=0 );
   if( pOp->opcode==OP_OpenWrite ){
-    wrFlag = 1;
-    if( pDb->pSchema->file_format < p->minWriteFileFormat ){
-      p->minWriteFileFormat = pDb->pSchema->file_format;
+    u.ax.wrFlag = 1;
+    assert( sqlite3SchemaMutexHeld(db, u.ax.iDb, 0) );
+    if( u.ax.pDb->pSchema->file_format < p->minWriteFileFormat ){
+      p->minWriteFileFormat = u.ax.pDb->pSchema->file_format;
     }
   }else{
-    wrFlag = 0;
+    u.ax.wrFlag = 0;
   }
-  if( pOp->p5 ){
-    assert( p2>0 );
-    assert( p2<=p->nMem );
-    pIn2 = &p->aMem[p2];
+  if( pOp->p5 & OPFLAG_P2ISREG ){
+    assert( u.ax.p2>0 );
+    assert( u.ax.p2<=p->nMem );
+    pIn2 = &aMem[u.ax.p2];
+    assert( memIsValid(pIn2) );
+    assert( (pIn2->flags & MEM_Int)!=0 );
     sqlite3VdbeMemIntegerify(pIn2);
-    p2 = (int)pIn2->u.i;
-    if( p2<2 ) {
+    u.ax.p2 = (int)pIn2->u.i;
+    /* The u.ax.p2 value always comes from a prior OP_CreateTable opcode and
+    ** that opcode will always set the u.ax.p2 value to 2 or more or else fail.
+    ** If there were a failure, the prepared statement would have halted
+    ** before reaching this instruction. */
+    if( NEVER(u.ax.p2<2) ) {
       rc = SQLITE_CORRUPT_BKPT;
       goto abort_due_to_error;
     }
   }
-  assert( i>=0 );
-  pCur = allocateCursor(p, i, &pOp[-1], iDb, 1);
-  if( pCur==0 ) goto no_mem;
-  pCur->nullRow = 1;
-  rc = sqlite3BtreeCursor(pX, p2, wrFlag, pOp->p4.p, pCur->pCursor);
   if( pOp->p4type==P4_KEYINFO ){
-    pCur->pKeyInfo = pOp->p4.pKeyInfo;
-    pCur->pKeyInfo->enc = ENC(p->db);
-  }else{
-    pCur->pKeyInfo = 0;
-  }
-  switch( rc ){
-    case SQLITE_BUSY: {
-      p->pc = pc;
-      p->rc = rc = SQLITE_BUSY;
-      goto vdbe_return;
-    }
-    case SQLITE_OK: {
-      int flags = sqlite3BtreeFlags(pCur->pCursor);
-      /* Sanity checking.  Only the lower four bits of the flags byte should
-      ** be used.  Bit 3 (mask 0x08) is unpredictable.  The lower 3 bits
-      ** (mask 0x07) should be either 5 (intkey+leafdata for tables) or
-      ** 2 (zerodata for indices).  If these conditions are not met it can
-      ** only mean that we are dealing with a corrupt database file
-      */
-      if( (flags & 0xf0)!=0 || ((flags & 0x07)!=5 && (flags & 0x07)!=2) ){
-        rc = SQLITE_CORRUPT_BKPT;
-        goto abort_due_to_error;
-      }
-      pCur->isTable = (flags & BTREE_INTKEY)!=0 ?1:0;
-      pCur->isIndex = (flags & BTREE_ZERODATA)!=0 ?1:0;
-      /* If P4==0 it means we are expected to open a table.  If P4!=0 then
-      ** we expect to be opening an index.  If this is not what happened,
-      ** then the database is corrupt
-      */
-      if( (pCur->isTable && pOp->p4type==P4_KEYINFO)
-       || (pCur->isIndex && pOp->p4type!=P4_KEYINFO) ){
-        rc = SQLITE_CORRUPT_BKPT;
-        goto abort_due_to_error;
-      }
-      break;
-    }
-    case SQLITE_EMPTY: {
-      pCur->isTable = pOp->p4type!=P4_KEYINFO;
-      pCur->isIndex = !pCur->isTable;
-      pCur->pCursor = 0;
-      rc = SQLITE_OK;
-      break;
-    }
-    default: {
-      goto abort_due_to_error;
-    }
+    u.ax.pKeyInfo = pOp->p4.pKeyInfo;
+    u.ax.pKeyInfo->enc = ENC(p->db);
+    u.ax.nField = u.ax.pKeyInfo->nField+1;
+  }else if( pOp->p4type==P4_INT32 ){
+    u.ax.nField = pOp->p4.i;
   }
+  assert( pOp->p1>=0 );
+  u.ax.pCur = allocateCursor(p, pOp->p1, u.ax.nField, u.ax.iDb, 1);
+  if( u.ax.pCur==0 ) goto no_mem;
+  u.ax.pCur->nullRow = 1;
+  u.ax.pCur->isOrdered = 1;
+  rc = sqlite3BtreeCursor(u.ax.pX, u.ax.p2, u.ax.wrFlag, u.ax.pKeyInfo, u.ax.pCur->pCursor);
+  u.ax.pCur->pKeyInfo = u.ax.pKeyInfo;
+  assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
+  sqlite3BtreeCursorHints(u.ax.pCur->pCursor, (pOp->p5 & OPFLAG_BULKCSR));
+
+  /* Since it performs no memory allocation or IO, the only value that
+  ** sqlite3BtreeCursor() may return is SQLITE_OK. */
+  assert( rc==SQLITE_OK );
+
+  /* Set the VdbeCursor.isTable and isIndex variables. Previous versions of
+  ** SQLite used to check if the root-page flags were sane at this point
+  ** and report database corruption if they were not, but this check has
+  ** since moved into the btree layer.  */
+  u.ax.pCur->isTable = pOp->p4type!=P4_KEYINFO;
+  u.ax.pCur->isIndex = !u.ax.pCur->isTable;
   break;
 }
 
-/* Opcode: OpenEphemeral P1 P2 * P4 *
+/* Opcode: OpenEphemeral P1 P2 * P4 P5
 **
 ** Open a new cursor P1 to a transient table.
 ** The cursor is always opened read/write even if 
-** the main database is read-only.  The transient or virtual
+** the main database is read-only.  The ephemeral
 ** table is deleted automatically when the cursor is closed.
 **
-** P2 is the number of columns in the virtual table.
+** P2 is the number of columns in the ephemeral table.
 ** The cursor points to a BTree table if P4==0 and to a BTree index
 ** if P4 is not 0.  If P4 is not NULL, it points to a KeyInfo structure
 ** that defines the format of keys in the index.
@@ -51665,84 +66711,119 @@ case OP_OpenWrite: {
 ** to a TEMP table at the SQL level, or to a table opened by
 ** this opcode.  Then this opcode was call OpenVirtual.  But
 ** that created confusion with the whole virtual-table idea.
+**
+** The P5 parameter can be a mask of the BTREE_* flags defined
+** in btree.h.  These flags control aspects of the operation of
+** the btree.  The BTREE_OMIT_JOURNAL and BTREE_SINGLE flags are
+** added automatically.
 */
+/* Opcode: OpenAutoindex P1 P2 * P4 *
+**
+** This opcode works the same as OP_OpenEphemeral.  It has a
+** different name to distinguish its use.  Tables created using
+** by this opcode will be used for automatically created transient
+** indices in joins.
+*/
+case OP_OpenAutoindex: 
 case OP_OpenEphemeral: {
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.ay */
   VdbeCursor *pCx;
-  static const int openFlags = 
+#endif /* local variables moved into u.ay */
+  static const int vfsFlags =
       SQLITE_OPEN_READWRITE |
       SQLITE_OPEN_CREATE |
       SQLITE_OPEN_EXCLUSIVE |
       SQLITE_OPEN_DELETEONCLOSE |
       SQLITE_OPEN_TRANSIENT_DB;
 
-  assert( i>=0 );
-  pCx = allocateCursor(p, i, pOp, -1, 1);
-  if( pCx==0 ) goto no_mem;
-  pCx->nullRow = 1;
-  rc = sqlite3BtreeFactory(db, 0, 1, SQLITE_DEFAULT_TEMP_CACHE_SIZE, openFlags,
-                           &pCx->pBt);
+  assert( pOp->p1>=0 );
+  u.ay.pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, 1);
+  if( u.ay.pCx==0 ) goto no_mem;
+  u.ay.pCx->nullRow = 1;
+  rc = sqlite3BtreeOpen(db->pVfs, 0, db, &u.ay.pCx->pBt,
+                        BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5, vfsFlags);
   if( rc==SQLITE_OK ){
-    rc = sqlite3BtreeBeginTrans(pCx->pBt, 1);
+    rc = sqlite3BtreeBeginTrans(u.ay.pCx->pBt, 1);
   }
   if( rc==SQLITE_OK ){
     /* If a transient index is required, create it by calling
-    ** sqlite3BtreeCreateTable() with the BTREE_ZERODATA flag before
+    ** sqlite3BtreeCreateTable() with the BTREE_BLOBKEY flag before
     ** opening it. If a transient table is required, just use the
-    ** automatically created table with root-page 1 (an INTKEY table).
+    ** automatically created table with root-page 1 (an BLOB_INTKEY table).
     */
     if( pOp->p4.pKeyInfo ){
       int pgno;
       assert( pOp->p4type==P4_KEYINFO );
-      rc = sqlite3BtreeCreateTable(pCx->pBt, &pgno, BTREE_ZERODATA); 
+      rc = sqlite3BtreeCreateTable(u.ay.pCx->pBt, &pgno, BTREE_BLOBKEY | pOp->p5);
       if( rc==SQLITE_OK ){
         assert( pgno==MASTER_ROOT+1 );
-        rc = sqlite3BtreeCursor(pCx->pBt, pgno, 1, 
-                                (KeyInfo*)pOp->p4.z, pCx->pCursor);
-        pCx->pKeyInfo = pOp->p4.pKeyInfo;
-        pCx->pKeyInfo->enc = ENC(p->db);
+        rc = sqlite3BtreeCursor(u.ay.pCx->pBt, pgno, 1,
+                                (KeyInfo*)pOp->p4.z, u.ay.pCx->pCursor);
+        u.ay.pCx->pKeyInfo = pOp->p4.pKeyInfo;
+        u.ay.pCx->pKeyInfo->enc = ENC(p->db);
       }
-      pCx->isTable = 0;
+      u.ay.pCx->isTable = 0;
     }else{
-      rc = sqlite3BtreeCursor(pCx->pBt, MASTER_ROOT, 1, 0, pCx->pCursor);
-      pCx->isTable = 1;
+      rc = sqlite3BtreeCursor(u.ay.pCx->pBt, MASTER_ROOT, 1, 0, u.ay.pCx->pCursor);
+      u.ay.pCx->isTable = 1;
     }
   }
-  pCx->isIndex = !pCx->isTable;
+  u.ay.pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
+  u.ay.pCx->isIndex = !u.ay.pCx->isTable;
   break;
 }
 
-/* Opcode: OpenPseudo P1 P2 * * *
+/* Opcode: OpenSorter P1 P2 * P4 *
+**
+** This opcode works like OP_OpenEphemeral except that it opens
+** a transient index that is specifically designed to sort large
+** tables using an external merge-sort algorithm.
+*/
+case OP_SorterOpen: {
+#if 0  /* local variables moved into u.az */
+  VdbeCursor *pCx;
+#endif /* local variables moved into u.az */
+#ifndef SQLITE_OMIT_MERGE_SORT
+  u.az.pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, 1);
+  if( u.az.pCx==0 ) goto no_mem;
+  u.az.pCx->pKeyInfo = pOp->p4.pKeyInfo;
+  u.az.pCx->pKeyInfo->enc = ENC(p->db);
+  u.az.pCx->isSorter = 1;
+  rc = sqlite3VdbeSorterInit(db, u.az.pCx);
+#else
+  pOp->opcode = OP_OpenEphemeral;
+  pc--;
+#endif
+  break;
+}
+
+/* Opcode: OpenPseudo P1 P2 P3 * *
 **
 ** Open a new cursor that points to a fake table that contains a single
-** row of data.  Any attempt to write a second row of data causes the
-** first row to be deleted.  All data is deleted when the cursor is
-** closed.
+** row of data.  The content of that one row in the content of memory
+** register P2.  In other words, cursor P1 becomes an alias for the 
+** MEM_Blob content contained in register P2.
 **
-** A pseudo-table created by this opcode is useful for holding the
-** NEW or OLD tables in a trigger.  Also used to hold the a single
+** A pseudo-table created by this opcode is used to hold a single
 ** row output from the sorter so that the row can be decomposed into
-** individual columns using the OP_Column opcode.
+** individual columns using the OP_Column opcode.  The OP_Column opcode
+** is the only cursor opcode that works with a pseudo-table.
 **
-** When OP_Insert is executed to insert a row in to the pseudo table,
-** the pseudo-table cursor may or may not make it's own copy of the
-** original row data. If P2 is 0, then the pseudo-table will copy the
-** original row data. Otherwise, a pointer to the original memory cell
-** is stored. In this case, the vdbe program must ensure that the 
-** memory cell containing the row data is not overwritten until the
-** pseudo table is closed (or a new row is inserted into it).
+** P3 is the number of fields in the records that will be stored by
+** the pseudo-table.
 */
 case OP_OpenPseudo: {
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.ba */
   VdbeCursor *pCx;
-  assert( i>=0 );
-  pCx = allocateCursor(p, i, &pOp[-1], -1, 0);
-  if( pCx==0 ) goto no_mem;
-  pCx->nullRow = 1;
-  pCx->pseudoTable = 1;
-  pCx->ephemPseudoTable = (u8)pOp->p2;
-  pCx->isTable = 1;
-  pCx->isIndex = 0;
+#endif /* local variables moved into u.ba */
+
+  assert( pOp->p1>=0 );
+  u.ba.pCx = allocateCursor(p, pOp->p1, pOp->p3, -1, 0);
+  if( u.ba.pCx==0 ) goto no_mem;
+  u.ba.pCx->nullRow = 1;
+  u.ba.pCx->pseudoTableReg = pOp->p2;
+  u.ba.pCx->isTable = 1;
+  u.ba.pCx->isIndex = 0;
   break;
 }
 
@@ -51752,10 +66833,9 @@ case OP_OpenPseudo: {
 ** currently open, this instruction is a no-op.
 */
 case OP_Close: {
-  int i = pOp->p1;
-  assert( i>=0 && i<p->nCursor );
-  sqlite3VdbeFreeCursor(p, p->apCsr[i]);
-  p->apCsr[i] = 0;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  sqlite3VdbeFreeCursor(p, p->apCsr[pOp->p1]);
+  p->apCsr[pOp->p1] = 0;
   break;
 }
 
@@ -51815,26 +66895,35 @@ case OP_SeekLt:         /* jump, in3 */
 case OP_SeekLe:         /* jump, in3 */
 case OP_SeekGe:         /* jump, in3 */
 case OP_SeekGt: {       /* jump, in3 */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bb */
+  int res;
+  int oc;
   VdbeCursor *pC;
+  UnpackedRecord r;
+  int nField;
+  i64 iKey;      /* The rowid we are to seek to */
+#endif /* local variables moved into u.bb */
 
-  assert( i>=0 && i<p->nCursor );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   assert( pOp->p2!=0 );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  if( pC->pCursor!=0 ){
-    int res, oc;
-    oc = pOp->opcode;
-    pC->nullRow = 0;
-    if( pC->isTable ){
-      i64 iKey;      /* The rowid we are to seek to */
-
+  u.bb.pC = p->apCsr[pOp->p1];
+  assert( u.bb.pC!=0 );
+  assert( u.bb.pC->pseudoTableReg==0 );
+  assert( OP_SeekLe == OP_SeekLt+1 );
+  assert( OP_SeekGe == OP_SeekLt+2 );
+  assert( OP_SeekGt == OP_SeekLt+3 );
+  assert( u.bb.pC->isOrdered );
+  if( ALWAYS(u.bb.pC->pCursor!=0) ){
+    u.bb.oc = pOp->opcode;
+    u.bb.pC->nullRow = 0;
+    if( u.bb.pC->isTable ){
       /* The input value in P3 might be of any type: integer, real, string,
       ** blob, or NULL.  But it needs to be an integer before we can do
       ** the seek, so covert it. */
+      pIn3 = &aMem[pOp->p3];
       applyNumericAffinity(pIn3);
-      iKey = sqlite3VdbeIntValue(pIn3);
-      pC->rowidIsValid = 0;
+      u.bb.iKey = sqlite3VdbeIntValue(pIn3);
+      u.bb.pC->rowidIsValid = 0;
 
       /* If the P3 value could not be converted into an integer without
       ** loss of information, then special processing is required... */
@@ -51849,92 +66938,104 @@ case OP_SeekGt: {       /* jump, in3 */
         ** point number. */
         assert( (pIn3->flags & MEM_Real)!=0 );
 
-        if( iKey==SMALLEST_INT64 && (pIn3->r<(double)iKey || pIn3->r>0) ){
-          /* The P3 value is to large in magnitude to be expressed as an
+        if( u.bb.iKey==SMALLEST_INT64 && (pIn3->r<(double)u.bb.iKey || pIn3->r>0) ){
+          /* The P3 value is too large in magnitude to be expressed as an
           ** integer. */
-          res = 1;
+          u.bb.res = 1;
           if( pIn3->r<0 ){
-            if( oc==OP_SeekGt || oc==OP_SeekGe ){
-              rc = sqlite3BtreeFirst(pC->pCursor, &res);
+            if( u.bb.oc>=OP_SeekGe ){  assert( u.bb.oc==OP_SeekGe || u.bb.oc==OP_SeekGt );
+              rc = sqlite3BtreeFirst(u.bb.pC->pCursor, &u.bb.res);
               if( rc!=SQLITE_OK ) goto abort_due_to_error;
             }
           }else{
-            if( oc==OP_SeekLt || oc==OP_SeekLe ){
-              rc = sqlite3BtreeLast(pC->pCursor, &res);
+            if( u.bb.oc<=OP_SeekLe ){  assert( u.bb.oc==OP_SeekLt || u.bb.oc==OP_SeekLe );
+              rc = sqlite3BtreeLast(u.bb.pC->pCursor, &u.bb.res);
               if( rc!=SQLITE_OK ) goto abort_due_to_error;
             }
           }
-          if( res ){
+          if( u.bb.res ){
             pc = pOp->p2 - 1;
           }
           break;
-        }else if( oc==OP_SeekLt || oc==OP_SeekGe ){
+        }else if( u.bb.oc==OP_SeekLt || u.bb.oc==OP_SeekGe ){
           /* Use the ceiling() function to convert real->int */
-          if( pIn3->r > (double)iKey ) iKey++;
+          if( pIn3->r > (double)u.bb.iKey ) u.bb.iKey++;
         }else{
           /* Use the floor() function to convert real->int */
-          assert( oc==OP_SeekLe || oc==OP_SeekGt );
-          if( pIn3->r < (double)iKey ) iKey--;
+          assert( u.bb.oc==OP_SeekLe || u.bb.oc==OP_SeekGt );
+          if( pIn3->r < (double)u.bb.iKey ) u.bb.iKey--;
         }
-      } 
-      rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, 0, (u64)iKey, 0, &res);
+      }
+      rc = sqlite3BtreeMovetoUnpacked(u.bb.pC->pCursor, 0, (u64)u.bb.iKey, 0, &u.bb.res);
       if( rc!=SQLITE_OK ){
         goto abort_due_to_error;
       }
-      if( res==0 ){
-        pC->rowidIsValid = 1;
-        pC->lastRowid = iKey;
+      if( u.bb.res==0 ){
+        u.bb.pC->rowidIsValid = 1;
+        u.bb.pC->lastRowid = u.bb.iKey;
       }
     }else{
-      UnpackedRecord r;
-      int nField = pOp->p4.i;
+      u.bb.nField = pOp->p4.i;
       assert( pOp->p4type==P4_INT32 );
-      assert( nField>0 );
-      r.pKeyInfo = pC->pKeyInfo;
-      r.nField = (u16)nField;
-      if( oc==OP_SeekGt || oc==OP_SeekLe ){
-        r.flags = UNPACKED_INCRKEY;
-      }else{
-        r.flags = 0;
-      }
-      r.aMem = &p->aMem[pOp->p3];
-      rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, &r, 0, 0, &res);
+      assert( u.bb.nField>0 );
+      u.bb.r.pKeyInfo = u.bb.pC->pKeyInfo;
+      u.bb.r.nField = (u16)u.bb.nField;
+
+      /* The next line of code computes as follows, only faster:
+      **   if( u.bb.oc==OP_SeekGt || u.bb.oc==OP_SeekLe ){
+      **     u.bb.r.flags = UNPACKED_INCRKEY;
+      **   }else{
+      **     u.bb.r.flags = 0;
+      **   }
+      */
+      u.bb.r.flags = (u16)(UNPACKED_INCRKEY * (1 & (u.bb.oc - OP_SeekLt)));
+      assert( u.bb.oc!=OP_SeekGt || u.bb.r.flags==UNPACKED_INCRKEY );
+      assert( u.bb.oc!=OP_SeekLe || u.bb.r.flags==UNPACKED_INCRKEY );
+      assert( u.bb.oc!=OP_SeekGe || u.bb.r.flags==0 );
+      assert( u.bb.oc!=OP_SeekLt || u.bb.r.flags==0 );
+
+      u.bb.r.aMem = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+      { int i; for(i=0; i<u.bb.r.nField; i++) assert( memIsValid(&u.bb.r.aMem[i]) ); }
+#endif
+      ExpandBlob(u.bb.r.aMem);
+      rc = sqlite3BtreeMovetoUnpacked(u.bb.pC->pCursor, &u.bb.r, 0, 0, &u.bb.res);
       if( rc!=SQLITE_OK ){
         goto abort_due_to_error;
       }
-      pC->rowidIsValid = 0;
+      u.bb.pC->rowidIsValid = 0;
     }
-    pC->deferredMoveto = 0;
-    pC->cacheStatus = CACHE_STALE;
+    u.bb.pC->deferredMoveto = 0;
+    u.bb.pC->cacheStatus = CACHE_STALE;
 #ifdef SQLITE_TEST
     sqlite3_search_count++;
 #endif
-    if( oc==OP_SeekGe || oc==OP_SeekGt ){
-      if( res<0 || (res==0 && oc==OP_SeekGt) ){
-        rc = sqlite3BtreeNext(pC->pCursor, &res);
+    if( u.bb.oc>=OP_SeekGe ){  assert( u.bb.oc==OP_SeekGe || u.bb.oc==OP_SeekGt );
+      if( u.bb.res<0 || (u.bb.res==0 && u.bb.oc==OP_SeekGt) ){
+        rc = sqlite3BtreeNext(u.bb.pC->pCursor, &u.bb.res);
         if( rc!=SQLITE_OK ) goto abort_due_to_error;
-        pC->rowidIsValid = 0;
+        u.bb.pC->rowidIsValid = 0;
       }else{
-        res = 0;
+        u.bb.res = 0;
       }
     }else{
-      assert( oc==OP_SeekLt || oc==OP_SeekLe );
-      if( res>0 || (res==0 && oc==OP_SeekLt) ){
-        rc = sqlite3BtreePrevious(pC->pCursor, &res);
+      assert( u.bb.oc==OP_SeekLt || u.bb.oc==OP_SeekLe );
+      if( u.bb.res>0 || (u.bb.res==0 && u.bb.oc==OP_SeekLt) ){
+        rc = sqlite3BtreePrevious(u.bb.pC->pCursor, &u.bb.res);
         if( rc!=SQLITE_OK ) goto abort_due_to_error;
-        pC->rowidIsValid = 0;
+        u.bb.pC->rowidIsValid = 0;
       }else{
-        /* res might be negative because the table is empty.  Check to
+        /* u.bb.res might be negative because the table is empty.  Check to
         ** see if this is the case.
         */
-        res = sqlite3BtreeEof(pC->pCursor);
+        u.bb.res = sqlite3BtreeEof(u.bb.pC->pCursor);
       }
     }
     assert( pOp->p2>0 );
-    if( res ){
+    if( u.bb.res ){
       pc = pOp->p2 - 1;
     }
-  }else if( !pC->pseudoTable ){
+  }else{
     /* This happens when attempting to open the sqlite3_master table
     ** for read access returns SQLITE_EMPTY. In this case always
     ** take the jump (since there are no records in the table).
@@ -51954,199 +67055,206 @@ case OP_SeekGt: {       /* jump, in3 */
 ** occur, no unnecessary I/O happens.
 */
 case OP_Seek: {    /* in2 */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bc */
   VdbeCursor *pC;
+#endif /* local variables moved into u.bc */
 
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  if( pC->pCursor!=0 ){
-    assert( pC->isTable );
-    pC->nullRow = 0;
-    pC->movetoTarget = sqlite3VdbeIntValue(pIn2);
-    pC->rowidIsValid = 0;
-    pC->deferredMoveto = 1;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bc.pC = p->apCsr[pOp->p1];
+  assert( u.bc.pC!=0 );
+  if( ALWAYS(u.bc.pC->pCursor!=0) ){
+    assert( u.bc.pC->isTable );
+    u.bc.pC->nullRow = 0;
+    pIn2 = &aMem[pOp->p2];
+    u.bc.pC->movetoTarget = sqlite3VdbeIntValue(pIn2);
+    u.bc.pC->rowidIsValid = 0;
+    u.bc.pC->deferredMoveto = 1;
   }
   break;
 }
   
 
-/* Opcode: Found P1 P2 P3 * *
+/* Opcode: Found P1 P2 P3 P4 *
 **
-** Register P3 holds a blob constructed by MakeRecord.  P1 is an index.
-** If an entry that matches the value in register p3 exists in P1 then
-** jump to P2.  If the P3 value does not match any entry in P1
-** then fall thru.  The P1 cursor is left pointing at the matching entry
-** if it exists.
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
 **
-** This instruction is used to implement the IN operator where the
-** left-hand side is a SELECT statement.  P1 may be a true index, or it
-** may be a temporary index that holds the results of the SELECT
-** statement.   This instruction is also used to implement the
-** DISTINCT keyword in SELECT statements.
-**
-** This instruction checks if index P1 contains a record for which 
-** the first N serialized values exactly match the N serialized values
-** in the record in register P3, where N is the total number of values in
-** the P3 record (the P3 record is a prefix of the P1 record). 
-**
-** See also: NotFound, IsUnique, NotExists
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is a prefix of any entry in P1 then a jump is made to P2 and
+** P1 is left pointing at the matching entry.
 */
-/* Opcode: NotFound P1 P2 P3 * *
+/* Opcode: NotFound P1 P2 P3 P4 *
 **
-** Register P3 holds a blob constructed by MakeRecord.  P1 is
-** an index.  If no entry exists in P1 that matches the blob then jump
-** to P2.  If an entry does existing, fall through.  The cursor is left
-** pointing to the entry that matches.
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+** 
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is not the prefix of any entry in P1 then a jump is made to P2.  If P1 
+** does contain an entry whose prefix matches the P3/P4 record then control
+** falls through to the next instruction and P1 is left pointing at the
+** matching entry.
 **
 ** See also: Found, NotExists, IsUnique
 */
 case OP_NotFound:       /* jump, in3 */
 case OP_Found: {        /* jump, in3 */
-  int i = pOp->p1;
-  int alreadyExists = 0;
+#if 0  /* local variables moved into u.bd */
+  int alreadyExists;
   VdbeCursor *pC;
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
-  if( (pC = p->apCsr[i])->pCursor!=0 ){
-    int res;
-    UnpackedRecord *pIdxKey;
+  int res;
+  char *pFree;
+  UnpackedRecord *pIdxKey;
+  UnpackedRecord r;
+  char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*3 + 7];
+#endif /* local variables moved into u.bd */
 
-    assert( pC->isTable==0 );
-    assert( pIn3->flags & MEM_Blob );
-    pIdxKey = sqlite3VdbeRecordUnpack(pC->pKeyInfo, pIn3->n, pIn3->z,
-                                      aTempRec, sizeof(aTempRec));
-    if( pIdxKey==0 ){
-      goto no_mem;
+#ifdef SQLITE_TEST
+  sqlite3_found_count++;
+#endif
+
+  u.bd.alreadyExists = 0;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_INT32 );
+  u.bd.pC = p->apCsr[pOp->p1];
+  assert( u.bd.pC!=0 );
+  pIn3 = &aMem[pOp->p3];
+  if( ALWAYS(u.bd.pC->pCursor!=0) ){
+
+    assert( u.bd.pC->isTable==0 );
+    if( pOp->p4.i>0 ){
+      u.bd.r.pKeyInfo = u.bd.pC->pKeyInfo;
+      u.bd.r.nField = (u16)pOp->p4.i;
+      u.bd.r.aMem = pIn3;
+#ifdef SQLITE_DEBUG
+      { int i; for(i=0; i<u.bd.r.nField; i++) assert( memIsValid(&u.bd.r.aMem[i]) ); }
+#endif
+      u.bd.r.flags = UNPACKED_PREFIX_MATCH;
+      u.bd.pIdxKey = &u.bd.r;
+    }else{
+      u.bd.pIdxKey = sqlite3VdbeAllocUnpackedRecord(
+          u.bd.pC->pKeyInfo, u.bd.aTempRec, sizeof(u.bd.aTempRec), &u.bd.pFree
+      );
+      if( u.bd.pIdxKey==0 ) goto no_mem;
+      assert( pIn3->flags & MEM_Blob );
+      assert( (pIn3->flags & MEM_Zero)==0 );  /* zeroblobs already expanded */
+      sqlite3VdbeRecordUnpack(u.bd.pC->pKeyInfo, pIn3->n, pIn3->z, u.bd.pIdxKey);
+      u.bd.pIdxKey->flags |= UNPACKED_PREFIX_MATCH;
     }
-    if( pOp->opcode==OP_Found ){
-      pIdxKey->flags |= UNPACKED_PREFIX_MATCH;
+    rc = sqlite3BtreeMovetoUnpacked(u.bd.pC->pCursor, u.bd.pIdxKey, 0, 0, &u.bd.res);
+    if( pOp->p4.i==0 ){
+      sqlite3DbFree(db, u.bd.pFree);
     }
-    rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, pIdxKey, 0, 0, &res);
-    sqlite3VdbeDeleteUnpackedRecord(pIdxKey);
     if( rc!=SQLITE_OK ){
       break;
     }
-    alreadyExists = (res==0);
-    pC->deferredMoveto = 0;
-    pC->cacheStatus = CACHE_STALE;
+    u.bd.alreadyExists = (u.bd.res==0);
+    u.bd.pC->deferredMoveto = 0;
+    u.bd.pC->cacheStatus = CACHE_STALE;
   }
   if( pOp->opcode==OP_Found ){
-    if( alreadyExists ) pc = pOp->p2 - 1;
+    if( u.bd.alreadyExists ) pc = pOp->p2 - 1;
   }else{
-    if( !alreadyExists ) pc = pOp->p2 - 1;
+    if( !u.bd.alreadyExists ) pc = pOp->p2 - 1;
   }
   break;
 }
 
 /* Opcode: IsUnique P1 P2 P3 P4 *
 **
-** The P3 register contains an integer record number.  Call this
-** record number R.  The P4 register contains an index key created
-** using MakeRecord.  Call it K.
+** Cursor P1 is open on an index b-tree - that is to say, a btree which
+** no data and where the key are records generated by OP_MakeRecord with
+** the list field being the integer ROWID of the entry that the index
+** entry refers to.
 **
-** P1 is an index.  So it has no data and its key consists of a
-** record generated by OP_MakeRecord where the last field is the 
-** rowid of the entry that the index refers to.
-** 
-** This instruction asks if there is an entry in P1 where the
-** fields matches K but the rowid is different from R.
-** If there is no such entry, then there is an immediate
-** jump to P2.  If any entry does exist where the index string
-** matches K but the record number is not R, then the record
-** number for that entry is written into P3 and control
-** falls through to the next instruction.
+** The P3 register contains an integer record number. Call this record 
+** number R. Register P4 is the first in a set of N contiguous registers
+** that make up an unpacked index key that can be used with cursor P1.
+** The value of N can be inferred from the cursor. N includes the rowid
+** value appended to the end of the index record. This rowid value may
+** or may not be the same as R.
+**
+** If any of the N registers beginning with register P4 contains a NULL
+** value, jump immediately to P2.
+**
+** Otherwise, this instruction checks if cursor P1 contains an entry
+** where the first (N-1) fields match but the rowid value at the end
+** of the index entry is not R. If there is no such entry, control jumps
+** to instruction P2. Otherwise, the rowid of the conflicting index
+** entry is copied to register P3 and control falls through to the next
+** instruction.
 **
 ** See also: NotFound, NotExists, Found
 */
 case OP_IsUnique: {        /* jump, in3 */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.be */
+  u16 ii;
   VdbeCursor *pCx;
   BtCursor *pCrsr;
-  Mem *pK;
-  i64 R;
+  u16 nField;
+  Mem *aMx;
+  UnpackedRecord r;                  /* B-Tree index search key */
+  i64 R;                             /* Rowid stored in register P3 */
+#endif /* local variables moved into u.be */
 
-  /* Pop the value R off the top of the stack
-  */
+  pIn3 = &aMem[pOp->p3];
+  u.be.aMx = &aMem[pOp->p4.i];
+  /* Assert that the values of parameters P1 and P4 are in range. */
   assert( pOp->p4type==P4_INT32 );
   assert( pOp->p4.i>0 && pOp->p4.i<=p->nMem );
-  pK = &p->aMem[pOp->p4.i];
-  sqlite3VdbeMemIntegerify(pIn3);
-  R = pIn3->u.i;
-  assert( i>=0 && i<p->nCursor );
-  pCx = p->apCsr[i];
-  assert( pCx!=0 );
-  pCrsr = pCx->pCursor;
-  if( pCrsr!=0 ){
-    int res;
-    i64 v;                     /* The record number that matches K */
-    UnpackedRecord *pIdxKey;   /* Unpacked version of P4 */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
 
-    /* Make sure K is a string and make zKey point to K
-    */
-    assert( pK->flags & MEM_Blob );
-    pIdxKey = sqlite3VdbeRecordUnpack(pCx->pKeyInfo, pK->n, pK->z,
-                                      aTempRec, sizeof(aTempRec));
-    if( pIdxKey==0 ){
-      goto no_mem;
-    }
-    pIdxKey->flags |= UNPACKED_IGNORE_ROWID;
+  /* Find the index cursor. */
+  u.be.pCx = p->apCsr[pOp->p1];
+  assert( u.be.pCx->deferredMoveto==0 );
+  u.be.pCx->seekResult = 0;
+  u.be.pCx->cacheStatus = CACHE_STALE;
+  u.be.pCrsr = u.be.pCx->pCursor;
 
-    /* Search for an entry in P1 where all but the last rowid match K
-    ** If there is no such entry, jump immediately to P2.
-    */
-    assert( pCx->deferredMoveto==0 );
-    pCx->cacheStatus = CACHE_STALE;
-    rc = sqlite3BtreeMovetoUnpacked(pCrsr, pIdxKey, 0, 0, &res);
-    if( rc!=SQLITE_OK ){
-      sqlite3VdbeDeleteUnpackedRecord(pIdxKey);
-      goto abort_due_to_error;
-    }
-    if( res<0 ){
-      rc = sqlite3BtreeNext(pCrsr, &res);
-      if( res ){
-        pc = pOp->p2 - 1;
-        sqlite3VdbeDeleteUnpackedRecord(pIdxKey);
-        break;
-      }
-    }
-    rc = sqlite3VdbeIdxKeyCompare(pCx, pIdxKey, &res); 
-    sqlite3VdbeDeleteUnpackedRecord(pIdxKey);
-    if( rc!=SQLITE_OK ) goto abort_due_to_error;
-    if( res>0 ){
+  /* If any of the values are NULL, take the jump. */
+  u.be.nField = u.be.pCx->pKeyInfo->nField;
+  for(u.be.ii=0; u.be.ii<u.be.nField; u.be.ii++){
+    if( u.be.aMx[u.be.ii].flags & MEM_Null ){
       pc = pOp->p2 - 1;
+      u.be.pCrsr = 0;
       break;
     }
+  }
+  assert( (u.be.aMx[u.be.nField].flags & MEM_Null)==0 );
 
-    /* At this point, pCrsr is pointing to an entry in P1 where all but
-    ** the final entry (the rowid) matches K.  Check to see if the
-    ** final rowid column is different from R.  If it equals R then jump
-    ** immediately to P2.
-    */
-    rc = sqlite3VdbeIdxRowid(pCrsr, &v);
-    if( rc!=SQLITE_OK ){
-      goto abort_due_to_error;
-    }
-    if( v==R ){
+  if( u.be.pCrsr!=0 ){
+    /* Populate the index search key. */
+    u.be.r.pKeyInfo = u.be.pCx->pKeyInfo;
+    u.be.r.nField = u.be.nField + 1;
+    u.be.r.flags = UNPACKED_PREFIX_SEARCH;
+    u.be.r.aMem = u.be.aMx;
+#ifdef SQLITE_DEBUG
+    { int i; for(i=0; i<u.be.r.nField; i++) assert( memIsValid(&u.be.r.aMem[i]) ); }
+#endif
+
+    /* Extract the value of u.be.R from register P3. */
+    sqlite3VdbeMemIntegerify(pIn3);
+    u.be.R = pIn3->u.i;
+
+    /* Search the B-Tree index. If no conflicting record is found, jump
+    ** to P2. Otherwise, copy the rowid of the conflicting record to
+    ** register P3 and fall through to the next instruction.  */
+    rc = sqlite3BtreeMovetoUnpacked(u.be.pCrsr, &u.be.r, 0, 0, &u.be.pCx->seekResult);
+    if( (u.be.r.flags & UNPACKED_PREFIX_SEARCH) || u.be.r.rowid==u.be.R ){
       pc = pOp->p2 - 1;
-      break;
+    }else{
+      pIn3->u.i = u.be.r.rowid;
     }
-
-    /* The final varint of the key is different from R.  Store it back
-    ** into register R3.  (The record number of an entry that violates
-    ** a UNIQUE constraint.)
-    */
-    pIn3->u.i = v;
-    assert( pIn3->flags&MEM_Int );
   }
   break;
 }
 
 /* Opcode: NotExists P1 P2 P3 * *
 **
-** Use the content of register P3 as a integer key.  If a record 
+** Use the content of register P3 as an integer key.  If a record 
 ** with that key does not exist in table of P1, then jump to P2. 
-** If the record does exist, then fall thru.  The cursor is left 
+** If the record does exist, then fall through.  The cursor is left 
 ** pointing to the record if it exists.
 **
 ** The difference between this operation and NotFound is that this
@@ -52157,33 +67265,42 @@ case OP_IsUnique: {        /* jump, in3 */
 ** See also: Found, NotFound, IsUnique
 */
 case OP_NotExists: {        /* jump, in3 */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bf */
   VdbeCursor *pC;
   BtCursor *pCrsr;
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
-  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
-    int res = 0;
-    u64 iKey;
-    assert( pIn3->flags & MEM_Int );
-    assert( p->apCsr[i]->isTable );
-    iKey = intToKey(pIn3->u.i);
-    rc = sqlite3BtreeMovetoUnpacked(pCrsr, 0, iKey, 0,&res);
-    pC->lastRowid = pIn3->u.i;
-    pC->rowidIsValid = res==0 ?1:0;
-    pC->nullRow = 0;
-    pC->cacheStatus = CACHE_STALE;
-    if( res!=0 ){
+  int res;
+  u64 iKey;
+#endif /* local variables moved into u.bf */
+
+  pIn3 = &aMem[pOp->p3];
+  assert( pIn3->flags & MEM_Int );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bf.pC = p->apCsr[pOp->p1];
+  assert( u.bf.pC!=0 );
+  assert( u.bf.pC->isTable );
+  assert( u.bf.pC->pseudoTableReg==0 );
+  u.bf.pCrsr = u.bf.pC->pCursor;
+  if( ALWAYS(u.bf.pCrsr!=0) ){
+    u.bf.res = 0;
+    u.bf.iKey = pIn3->u.i;
+    rc = sqlite3BtreeMovetoUnpacked(u.bf.pCrsr, 0, u.bf.iKey, 0, &u.bf.res);
+    u.bf.pC->lastRowid = pIn3->u.i;
+    u.bf.pC->rowidIsValid = u.bf.res==0 ?1:0;
+    u.bf.pC->nullRow = 0;
+    u.bf.pC->cacheStatus = CACHE_STALE;
+    u.bf.pC->deferredMoveto = 0;
+    if( u.bf.res!=0 ){
       pc = pOp->p2 - 1;
-      assert( pC->rowidIsValid==0 );
+      assert( u.bf.pC->rowidIsValid==0 );
     }
-  }else if( !pC->pseudoTable ){
-    /* This happens when an attempt to open a read cursor on the 
+    u.bf.pC->seekResult = u.bf.res;
+  }else{
+    /* This happens when an attempt to open a read cursor on the
     ** sqlite_master table returns SQLITE_EMPTY.
     */
-    assert( pC->isTable );
     pc = pOp->p2 - 1;
-    assert( pC->rowidIsValid==0 );
+    assert( u.bf.pC->rowidIsValid==0 );
+    u.bf.pC->seekResult = 0;
   }
   break;
 }
@@ -52196,11 +67313,9 @@ case OP_NotExists: {        /* jump, in3 */
 ** instruction.  
 */
 case OP_Sequence: {           /* out2-prerelease */
-  int i = pOp->p1;
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
-  pOut->u.i = p->apCsr[i]->seqCount++;
-  MemSetTypeFlag(pOut, MEM_Int);
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( p->apCsr[pOp->p1]!=0 );
+  pOut->u.i = p->apCsr[pOp->p1]->seqCount++;
   break;
 }
 
@@ -52212,20 +67327,29 @@ case OP_Sequence: {           /* out2-prerelease */
 ** table that cursor P1 points to.  The new record number is written
 ** written to register P2.
 **
-** If P3>0 then P3 is a register that holds the largest previously
-** generated record number.  No new record numbers are allowed to be less
-** than this value.  When this value reaches its maximum, a SQLITE_FULL
-** error is generated.  The P3 register is updated with the generated
-** record number.  This P3 mechanism is used to help implement the
+** If P3>0 then P3 is a register in the root frame of this VDBE that holds 
+** the largest previously generated record number. No new record numbers are
+** allowed to be less than this value. When this value reaches its maximum, 
+** an SQLITE_FULL error is generated. The P3 register is updated with the '
+** generated record number. This P3 mechanism is used to help implement the
 ** AUTOINCREMENT feature.
 */
 case OP_NewRowid: {           /* out2-prerelease */
-  int i = pOp->p1;
-  i64 v = 0;
-  VdbeCursor *pC;
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
-  if( (pC = p->apCsr[i])->pCursor==0 ){
+#if 0  /* local variables moved into u.bg */
+  i64 v;                 /* The new rowid */
+  VdbeCursor *pC;        /* Cursor of table to get the new rowid */
+  int res;               /* Result of an sqlite3BtreeLast() */
+  int cnt;               /* Counter to limit the number of searches */
+  Mem *pMem;             /* Register holding largest rowid for AUTOINCREMENT */
+  VdbeFrame *pFrame;     /* Root frame of VDBE */
+#endif /* local variables moved into u.bg */
+
+  u.bg.v = 0;
+  u.bg.res = 0;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bg.pC = p->apCsr[pOp->p1];
+  assert( u.bg.pC!=0 );
+  if( NEVER(u.bg.pC->pCursor==0) ){
     /* The zero initialization above is all that is needed */
   }else{
     /* The next rowid or record number (different terms for the same
@@ -52239,36 +67363,9 @@ case OP_NewRowid: {           /* out2-prerelease */
     ** The second algorithm is to select a rowid at random and see if
     ** it already exists in the table.  If it does not exist, we have
     ** succeeded.  If the random rowid does exist, we select a new one
-    ** and try again, up to 1000 times.
-    **
-    ** For a table with less than 2 billion entries, the probability
-    ** of not finding a unused rowid is about 1.0e-300.  This is a 
-    ** non-zero probability, but it is still vanishingly small and should
-    ** never cause a problem.  You are much, much more likely to have a
-    ** hardware failure than for this algorithm to fail.
-    **
-    ** The analysis in the previous paragraph assumes that you have a good
-    ** source of random numbers.  Is a library function like lrand48()
-    ** good enough?  Maybe. Maybe not. It's hard to know whether there
-    ** might be subtle bugs is some implementations of lrand48() that
-    ** could cause problems. To avoid uncertainty, SQLite uses its own 
-    ** random number generator based on the RC4 algorithm.
-    **
-    ** To promote locality of reference for repetitive inserts, the
-    ** first few attempts at choosing a random rowid pick values just a little
-    ** larger than the previous rowid.  This has been shown experimentally
-    ** to double the speed of the COPY operation.
+    ** and try again, up to 100 times.
     */
-    int res, rx=SQLITE_OK, cnt;
-    i64 x;
-    cnt = 0;
-    if( (sqlite3BtreeFlags(pC->pCursor)&(BTREE_INTKEY|BTREE_ZERODATA)) !=
-          BTREE_INTKEY ){
-      rc = SQLITE_CORRUPT_BKPT;
-      goto abort_due_to_error;
-    }
-    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_INTKEY)!=0 );
-    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_ZERODATA)==0 );
+    assert( u.bg.pC->isTable );
 
 #ifdef SQLITE_32BIT_ROWID
 #   define MAX_ROWID 0x7fffffff
@@ -52280,81 +67377,97 @@ case OP_NewRowid: {           /* out2-prerelease */
 #   define MAX_ROWID  (i64)( (((u64)0x7fffffff)<<32) | (u64)0xffffffff )
 #endif
 
-    if( !pC->useRandomRowid ){
-      if( pC->nextRowidValid ){
-        v = pC->nextRowid;
-      }else{
-        rc = sqlite3BtreeLast(pC->pCursor, &res);
+    if( !u.bg.pC->useRandomRowid ){
+      u.bg.v = sqlite3BtreeGetCachedRowid(u.bg.pC->pCursor);
+      if( u.bg.v==0 ){
+        rc = sqlite3BtreeLast(u.bg.pC->pCursor, &u.bg.res);
         if( rc!=SQLITE_OK ){
           goto abort_due_to_error;
         }
-        if( res ){
-          v = 1;
+        if( u.bg.res ){
+          u.bg.v = 1;   /* IMP: R-61914-48074 */
         }else{
-          sqlite3BtreeKeySize(pC->pCursor, &v);
-          v = keyToInt(v);
-          if( v==MAX_ROWID ){
-            pC->useRandomRowid = 1;
+          assert( sqlite3BtreeCursorIsValid(u.bg.pC->pCursor) );
+          rc = sqlite3BtreeKeySize(u.bg.pC->pCursor, &u.bg.v);
+          assert( rc==SQLITE_OK );   /* Cannot fail following BtreeLast() */
+          if( u.bg.v>=MAX_ROWID ){
+            u.bg.pC->useRandomRowid = 1;
           }else{
-            v++;
+            u.bg.v++;   /* IMP: R-29538-34987 */
           }
         }
       }
 
 #ifndef SQLITE_OMIT_AUTOINCREMENT
       if( pOp->p3 ){
-        Mem *pMem;
-        assert( pOp->p3>0 && pOp->p3<=p->nMem ); /* P3 is a valid memory cell */
-        pMem = &p->aMem[pOp->p3];
-	REGISTER_TRACE(pOp->p3, pMem);
-        sqlite3VdbeMemIntegerify(pMem);
-        assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
-        if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
-          rc = SQLITE_FULL;
+        /* Assert that P3 is a valid memory cell. */
+        assert( pOp->p3>0 );
+        if( p->pFrame ){
+          for(u.bg.pFrame=p->pFrame; u.bg.pFrame->pParent; u.bg.pFrame=u.bg.pFrame->pParent);
+          /* Assert that P3 is a valid memory cell. */
+          assert( pOp->p3<=u.bg.pFrame->nMem );
+          u.bg.pMem = &u.bg.pFrame->aMem[pOp->p3];
+        }else{
+          /* Assert that P3 is a valid memory cell. */
+          assert( pOp->p3<=p->nMem );
+          u.bg.pMem = &aMem[pOp->p3];
+          memAboutToChange(p, u.bg.pMem);
+        }
+        assert( memIsValid(u.bg.pMem) );
+
+        REGISTER_TRACE(pOp->p3, u.bg.pMem);
+        sqlite3VdbeMemIntegerify(u.bg.pMem);
+        assert( (u.bg.pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
+        if( u.bg.pMem->u.i==MAX_ROWID || u.bg.pC->useRandomRowid ){
+          rc = SQLITE_FULL;   /* IMP: R-12275-61338 */
           goto abort_due_to_error;
         }
-        if( v<pMem->u.i+1 ){
-          v = pMem->u.i + 1;
+        if( u.bg.v<u.bg.pMem->u.i+1 ){
+          u.bg.v = u.bg.pMem->u.i + 1;
         }
-        pMem->u.i = v;
+        u.bg.pMem->u.i = u.bg.v;
       }
 #endif
 
-      if( v<MAX_ROWID ){
-        pC->nextRowidValid = 1;
-        pC->nextRowid = v+1;
-      }else{
-        pC->nextRowidValid = 0;
-      }
+      sqlite3BtreeSetCachedRowid(u.bg.pC->pCursor, u.bg.v<MAX_ROWID ? u.bg.v+1 : 0);
     }
-    if( pC->useRandomRowid ){
-      assert( pOp->p3==0 );  /* SQLITE_FULL must have occurred prior to this */
-      v = db->priorNewRowid;
-      cnt = 0;
-      do{
-        if( cnt==0 && (v&0xffffff)==v ){
-          v++;
+    if( u.bg.pC->useRandomRowid ){
+      /* IMPLEMENTATION-OF: R-07677-41881 If the largest ROWID is equal to the
+      ** largest possible integer (9223372036854775807) then the database
+      ** engine starts picking positive candidate ROWIDs at random until
+      ** it finds one that is not previously used. */
+      assert( pOp->p3==0 );  /* We cannot be in random rowid mode if this is
+                             ** an AUTOINCREMENT table. */
+      /* on the first attempt, simply do one more than previous */
+      u.bg.v = lastRowid;
+      u.bg.v &= (MAX_ROWID>>1); /* ensure doesn't go negative */
+      u.bg.v++; /* ensure non-zero */
+      u.bg.cnt = 0;
+      while(   ((rc = sqlite3BtreeMovetoUnpacked(u.bg.pC->pCursor, 0, (u64)u.bg.v,
+                                                 0, &u.bg.res))==SQLITE_OK)
+            && (u.bg.res==0)
+            && (++u.bg.cnt<100)){
+        /* collision - try another random rowid */
+        sqlite3_randomness(sizeof(u.bg.v), &u.bg.v);
+        if( u.bg.cnt<5 ){
+          /* try "small" random rowids for the initial attempts */
+          u.bg.v &= 0xffffff;
         }else{
-          sqlite3_randomness(sizeof(v), &v);
-          if( cnt<5 ) v &= 0xffffff;
+          u.bg.v &= (MAX_ROWID>>1); /* ensure doesn't go negative */
         }
-        if( v==0 ) continue;
-        x = intToKey(v);
-        rx = sqlite3BtreeMovetoUnpacked(pC->pCursor, 0, (u64)x, 0, &res);
-        cnt++;
-      }while( cnt<100 && rx==SQLITE_OK && res==0 );
-      db->priorNewRowid = v;
-      if( rx==SQLITE_OK && res==0 ){
-        rc = SQLITE_FULL;
+        u.bg.v++; /* ensure non-zero */
+      }
+      if( rc==SQLITE_OK && u.bg.res==0 ){
+        rc = SQLITE_FULL;   /* IMP: R-38219-53002 */
         goto abort_due_to_error;
       }
+      assert( u.bg.v>0 );  /* EV: R-40812-03570 */
     }
-    pC->rowidIsValid = 0;
-    pC->deferredMoveto = 0;
-    pC->cacheStatus = CACHE_STALE;
+    u.bg.pC->rowidIsValid = 0;
+    u.bg.pC->deferredMoveto = 0;
+    u.bg.pC->cacheStatus = CACHE_STALE;
   }
-  MemSetTypeFlag(pOut, MEM_Int);
-  pOut->u.i = v;
+  pOut->u.i = u.bg.v;
   break;
 }
 
@@ -52362,15 +67475,28 @@ case OP_NewRowid: {           /* out2-prerelease */
 **
 ** Write an entry into the table of cursor P1.  A new entry is
 ** created if it doesn't already exist or the data for an existing
-** entry is overwritten.  The data is the value stored register
+** entry is overwritten.  The data is the value MEM_Blob stored in register
 ** number P2. The key is stored in register P3. The key must
-** be an integer.
+** be a MEM_Int.
 **
 ** If the OPFLAG_NCHANGE flag of P5 is set, then the row change count is
 ** incremented (otherwise not).  If the OPFLAG_LASTROWID flag of P5 is set,
 ** then rowid is stored for subsequent return by the
 ** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
 **
+** If the OPFLAG_USESEEKRESULT flag of P5 is set and if the result of
+** the last seek operation (OP_NotExists) was a success, then this
+** operation will not attempt to find the appropriate row before doing
+** the insert but will instead overwrite the row that the cursor is
+** currently pointing to.  Presumably, the prior OP_NotExists opcode
+** has already positioned the cursor correctly.  This is an optimization
+** that boosts performance by avoiding redundant seeks.
+**
+** If the OPFLAG_ISUPDATE flag is set, then this opcode is part of an
+** UPDATE operation.  Otherwise (if the flag is clear) then this opcode
+** is part of an INSERT operation.  The difference is only important to
+** the update hook.
+**
 ** Parameter P4 may point to a string containing the table-name, or
 ** may be NULL. If it is not NULL, then the update-hook 
 ** (sqlite3.xUpdateCallback) is invoked following a successful insert.
@@ -52384,79 +67510,77 @@ case OP_NewRowid: {           /* out2-prerelease */
 ** This instruction only works on tables.  The equivalent instruction
 ** for indices is OP_IdxInsert.
 */
-case OP_Insert: {
-  Mem *pData = &p->aMem[pOp->p2];
-  Mem *pKey = &p->aMem[pOp->p3];
+/* Opcode: InsertInt P1 P2 P3 P4 P5
+**
+** This works exactly like OP_Insert except that the key is the
+** integer value P3, not the value of the integer stored in register P3.
+*/
+case OP_Insert: 
+case OP_InsertInt: {
+#if 0  /* local variables moved into u.bh */
+  Mem *pData;       /* MEM cell holding data for the record to be inserted */
+  Mem *pKey;        /* MEM cell holding key  for the record */
+  i64 iKey;         /* The integer ROWID or key for the record to be inserted */
+  VdbeCursor *pC;   /* Cursor to table into which insert is written */
+  int nZero;        /* Number of zero-bytes to append */
+  int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
+  const char *zDb;  /* database name - used by the update hook */
+  const char *zTbl; /* Table name - used by the opdate hook */
+  int op;           /* Opcode for update hook: SQLITE_UPDATE or SQLITE_INSERT */
+#endif /* local variables moved into u.bh */
 
-  i64 iKey;   /* The integer ROWID or key for the record to be inserted */
-  int i = pOp->p1;
-  VdbeCursor *pC;
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  assert( pC->pCursor!=0 || pC->pseudoTable );
-  assert( pKey->flags & MEM_Int );
-  assert( pC->isTable );
-  REGISTER_TRACE(pOp->p2, pData);
-  REGISTER_TRACE(pOp->p3, pKey);
+  u.bh.pData = &aMem[pOp->p2];
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( memIsValid(u.bh.pData) );
+  u.bh.pC = p->apCsr[pOp->p1];
+  assert( u.bh.pC!=0 );
+  assert( u.bh.pC->pCursor!=0 );
+  assert( u.bh.pC->pseudoTableReg==0 );
+  assert( u.bh.pC->isTable );
+  REGISTER_TRACE(pOp->p2, u.bh.pData);
+
+  if( pOp->opcode==OP_Insert ){
+    u.bh.pKey = &aMem[pOp->p3];
+    assert( u.bh.pKey->flags & MEM_Int );
+    assert( memIsValid(u.bh.pKey) );
+    REGISTER_TRACE(pOp->p3, u.bh.pKey);
+    u.bh.iKey = u.bh.pKey->u.i;
+  }else{
+    assert( pOp->opcode==OP_InsertInt );
+    u.bh.iKey = pOp->p3;
+  }
 
-  iKey = intToKey(pKey->u.i);
   if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
-  if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = pKey->u.i;
-  if( pC->nextRowidValid && pKey->u.i>=pC->nextRowid ){
-    pC->nextRowidValid = 0;
-  }
-  if( pData->flags & MEM_Null ){
-    pData->z = 0;
-    pData->n = 0;
+  if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = lastRowid = u.bh.iKey;
+  if( u.bh.pData->flags & MEM_Null ){
+    u.bh.pData->z = 0;
+    u.bh.pData->n = 0;
   }else{
-    assert( pData->flags & (MEM_Blob|MEM_Str) );
+    assert( u.bh.pData->flags & (MEM_Blob|MEM_Str) );
   }
-  if( pC->pseudoTable ){
-    if( !pC->ephemPseudoTable ){
-      sqlite3DbFree(db, pC->pData);
-    }
-    pC->iKey = iKey;
-    pC->nData = pData->n;
-    if( pData->z==pData->zMalloc || pC->ephemPseudoTable ){
-      pC->pData = pData->z;
-      if( !pC->ephemPseudoTable ){
-        pData->flags &= ~MEM_Dyn;
-        pData->flags |= MEM_Ephem;
-        pData->zMalloc = 0;
-      }
-    }else{
-      pC->pData = sqlite3Malloc( pC->nData+2 );
-      if( !pC->pData ) goto no_mem;
-      memcpy(pC->pData, pData->z, pC->nData);
-      pC->pData[pC->nData] = 0;
-      pC->pData[pC->nData+1] = 0;
-    }
-    pC->nullRow = 0;
+  u.bh.seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? u.bh.pC->seekResult : 0);
+  if( u.bh.pData->flags & MEM_Zero ){
+    u.bh.nZero = u.bh.pData->u.nZero;
   }else{
-    int nZero;
-    if( pData->flags & MEM_Zero ){
-      nZero = pData->u.nZero;
-    }else{
-      nZero = 0;
-    }
-    rc = sqlite3BtreeInsert(pC->pCursor, 0, iKey,
-                            pData->z, pData->n, nZero,
-                            pOp->p5 & OPFLAG_APPEND);
+    u.bh.nZero = 0;
   }
-  
-  pC->rowidIsValid = 0;
-  pC->deferredMoveto = 0;
-  pC->cacheStatus = CACHE_STALE;
+  sqlite3BtreeSetCachedRowid(u.bh.pC->pCursor, 0);
+  rc = sqlite3BtreeInsert(u.bh.pC->pCursor, 0, u.bh.iKey,
+                          u.bh.pData->z, u.bh.pData->n, u.bh.nZero,
+                          pOp->p5 & OPFLAG_APPEND, u.bh.seekResult
+  );
+  u.bh.pC->rowidIsValid = 0;
+  u.bh.pC->deferredMoveto = 0;
+  u.bh.pC->cacheStatus = CACHE_STALE;
 
   /* Invoke the update-hook if required. */
   if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p4.z ){
-    const char *zDb = db->aDb[pC->iDb].zName;
-    const char *zTbl = pOp->p4.z;
-    int op = ((pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
-    assert( pC->isTable );
-    db->xUpdateCallback(db->pUpdateArg, op, zDb, zTbl, iKey);
-    assert( pC->iDb>=0 );
+    u.bh.zDb = db->aDb[u.bh.pC->iDb].zName;
+    u.bh.zTbl = pOp->p4.z;
+    u.bh.op = ((pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
+    assert( u.bh.pC->isTable );
+    db->xUpdateCallback(db->pUpdateArg, u.bh.op, u.bh.zDb, u.bh.zTbl, u.bh.iKey);
+    assert( u.bh.pC->iDb>=0 );
   }
   break;
 }
@@ -52482,56 +67606,107 @@ case OP_Insert: {
 ** using OP_NotFound prior to invoking this opcode.
 */
 case OP_Delete: {
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bi */
   i64 iKey;
   VdbeCursor *pC;
+#endif /* local variables moved into u.bi */
 
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  assert( pC->pCursor!=0 );  /* Only valid for real tables, no pseudotables */
+  u.bi.iKey = 0;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bi.pC = p->apCsr[pOp->p1];
+  assert( u.bi.pC!=0 );
+  assert( u.bi.pC->pCursor!=0 );  /* Only valid for real tables, no pseudotables */
 
-  /* If the update-hook will be invoked, set iKey to the rowid of the
+  /* If the update-hook will be invoked, set u.bi.iKey to the rowid of the
   ** row being deleted.
   */
   if( db->xUpdateCallback && pOp->p4.z ){
-    assert( pC->isTable );
-    assert( pC->rowidIsValid );  /* lastRowid set by previous OP_NotFound */
-    iKey = pC->lastRowid;
+    assert( u.bi.pC->isTable );
+    assert( u.bi.pC->rowidIsValid );  /* lastRowid set by previous OP_NotFound */
+    u.bi.iKey = u.bi.pC->lastRowid;
   }
 
-  rc = sqlite3VdbeCursorMoveto(pC);
-  if( rc ) goto abort_due_to_error;
-  rc = sqlite3BtreeDelete(pC->pCursor);
-  pC->nextRowidValid = 0;
-  pC->cacheStatus = CACHE_STALE;
+  /* The OP_Delete opcode always follows an OP_NotExists or OP_Last or
+  ** OP_Column on the same table without any intervening operations that
+  ** might move or invalidate the cursor.  Hence cursor u.bi.pC is always pointing
+  ** to the row to be deleted and the sqlite3VdbeCursorMoveto() operation
+  ** below is always a no-op and cannot fail.  We will run it anyhow, though,
+  ** to guard against future changes to the code generator.
+  **/
+  assert( u.bi.pC->deferredMoveto==0 );
+  rc = sqlite3VdbeCursorMoveto(u.bi.pC);
+  if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
+
+  sqlite3BtreeSetCachedRowid(u.bi.pC->pCursor, 0);
+  rc = sqlite3BtreeDelete(u.bi.pC->pCursor);
+  u.bi.pC->cacheStatus = CACHE_STALE;
 
   /* Invoke the update-hook if required. */
   if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p4.z ){
-    const char *zDb = db->aDb[pC->iDb].zName;
+    const char *zDb = db->aDb[u.bi.pC->iDb].zName;
     const char *zTbl = pOp->p4.z;
-    db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, zTbl, iKey);
-    assert( pC->iDb>=0 );
+    db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, zTbl, u.bi.iKey);
+    assert( u.bi.pC->iDb>=0 );
   }
   if( pOp->p2 & OPFLAG_NCHANGE ) p->nChange++;
   break;
 }
-
-/* Opcode: ResetCount P1 * *
+/* Opcode: ResetCount * * * * *
 **
-** This opcode resets the VMs internal change counter to 0. If P1 is true,
-** then the value of the change counter is copied to the database handle
-** change counter (returned by subsequent calls to sqlite3_changes())
-** before it is reset. This is used by trigger programs.
+** The value of the change counter is copied to the database handle
+** change counter (returned by subsequent calls to sqlite3_changes()).
+** Then the VMs internal change counter resets to 0.
+** This is used by trigger programs.
 */
 case OP_ResetCount: {
-  if( pOp->p1 ){
-    sqlite3VdbeSetChanges(db, p->nChange);
-  }
+  sqlite3VdbeSetChanges(db, p->nChange);
   p->nChange = 0;
   break;
 }
 
+/* Opcode: SorterCompare P1 P2 P3
+**
+** P1 is a sorter cursor. This instruction compares the record blob in 
+** register P3 with the entry that the sorter cursor currently points to.
+** If, excluding the rowid fields at the end, the two records are a match,
+** fall through to the next instruction. Otherwise, jump to instruction P2.
+*/
+case OP_SorterCompare: {
+#if 0  /* local variables moved into u.bj */
+  VdbeCursor *pC;
+  int res;
+#endif /* local variables moved into u.bj */
+
+  u.bj.pC = p->apCsr[pOp->p1];
+  assert( isSorter(u.bj.pC) );
+  pIn3 = &aMem[pOp->p3];
+  rc = sqlite3VdbeSorterCompare(u.bj.pC, pIn3, &u.bj.res);
+  if( u.bj.res ){
+    pc = pOp->p2-1;
+  }
+  break;
+};
+
+/* Opcode: SorterData P1 P2 * * *
+**
+** Write into register P2 the current sorter data for sorter cursor P1.
+*/
+case OP_SorterData: {
+#if 0  /* local variables moved into u.bk */
+  VdbeCursor *pC;
+#endif /* local variables moved into u.bk */
+#ifndef SQLITE_OMIT_MERGE_SORT
+  pOut = &aMem[pOp->p2];
+  u.bk.pC = p->apCsr[pOp->p1];
+  assert( u.bk.pC->isSorter );
+  rc = sqlite3VdbeSorterRowkey(u.bk.pC, pOut);
+#else
+  pOp->opcode = OP_RowKey;
+  pc--;
+#endif
+  break;
+}
+
 /* Opcode: RowData P1 P2 * * *
 **
 ** Write into register P2 the complete row data for cursor P1.
@@ -52554,48 +67729,62 @@ case OP_ResetCount: {
 */
 case OP_RowKey:
 case OP_RowData: {
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bl */
   VdbeCursor *pC;
   BtCursor *pCrsr;
   u32 n;
+  i64 n64;
+#endif /* local variables moved into u.bl */
 
-  pOut = &p->aMem[pOp->p2];
+  pOut = &aMem[pOp->p2];
+  memAboutToChange(p, pOut);
 
   /* Note that RowKey and RowData are really exactly the same instruction */
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC->isTable || pOp->opcode==OP_RowKey );
-  assert( pC->isIndex || pOp->opcode==OP_RowData );
-  assert( pC!=0 );
-  assert( pC->nullRow==0 );
-  assert( pC->pseudoTable==0 );
-  assert( pC->pCursor!=0 );
-  pCrsr = pC->pCursor;
-  rc = sqlite3VdbeCursorMoveto(pC);
-  if( rc ) goto abort_due_to_error;
-  if( pC->isIndex ){
-    i64 n64;
-    assert( !pC->isTable );
-    sqlite3BtreeKeySize(pCrsr, &n64);
-    if( n64>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bl.pC = p->apCsr[pOp->p1];
+  assert( u.bl.pC->isSorter==0 );
+  assert( u.bl.pC->isTable || pOp->opcode!=OP_RowData );
+  assert( u.bl.pC->isIndex || pOp->opcode==OP_RowData );
+  assert( u.bl.pC!=0 );
+  assert( u.bl.pC->nullRow==0 );
+  assert( u.bl.pC->pseudoTableReg==0 );
+  assert( u.bl.pC->pCursor!=0 );
+  u.bl.pCrsr = u.bl.pC->pCursor;
+  assert( sqlite3BtreeCursorIsValid(u.bl.pCrsr) );
+
+  /* The OP_RowKey and OP_RowData opcodes always follow OP_NotExists or
+  ** OP_Rewind/Op_Next with no intervening instructions that might invalidate
+  ** the cursor.  Hence the following sqlite3VdbeCursorMoveto() call is always
+  ** a no-op and can never fail.  But we leave it in place as a safety.
+  */
+  assert( u.bl.pC->deferredMoveto==0 );
+  rc = sqlite3VdbeCursorMoveto(u.bl.pC);
+  if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
+
+  if( u.bl.pC->isIndex ){
+    assert( !u.bl.pC->isTable );
+    VVA_ONLY(rc =) sqlite3BtreeKeySize(u.bl.pCrsr, &u.bl.n64);
+    assert( rc==SQLITE_OK );    /* True because of CursorMoveto() call above */
+    if( u.bl.n64>db->aLimit[SQLITE_LIMIT_LENGTH] ){
       goto too_big;
     }
-    n = (int)n64;
+    u.bl.n = (u32)u.bl.n64;
   }else{
-    sqlite3BtreeDataSize(pCrsr, &n);
-    if( (int)n>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    VVA_ONLY(rc =) sqlite3BtreeDataSize(u.bl.pCrsr, &u.bl.n);
+    assert( rc==SQLITE_OK );    /* DataSize() cannot fail */
+    if( u.bl.n>(u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
       goto too_big;
     }
   }
-  if( sqlite3VdbeMemGrow(pOut, n, 0) ){
+  if( sqlite3VdbeMemGrow(pOut, u.bl.n, 0) ){
     goto no_mem;
   }
-  pOut->n = n;
+  pOut->n = u.bl.n;
   MemSetTypeFlag(pOut, MEM_Blob);
-  if( pC->isIndex ){
-    rc = sqlite3BtreeKey(pCrsr, 0, n, pOut->z);
+  if( u.bl.pC->isIndex ){
+    rc = sqlite3BtreeKey(u.bl.pCrsr, 0, u.bl.n, pOut->z);
   }else{
-    rc = sqlite3BtreeData(pCrsr, 0, n, pOut->z);
+    rc = sqlite3BtreeData(u.bl.pCrsr, 0, u.bl.n, pOut->z);
   }
   pOut->enc = SQLITE_UTF8;  /* In case the blob is ever cast to text */
   UPDATE_MAX_BLOBSIZE(pOut);
@@ -52606,31 +67795,48 @@ case OP_RowData: {
 **
 ** Store in register P2 an integer which is the key of the table entry that
 ** P1 is currently point to.
+**
+** P1 can be either an ordinary table or a virtual table.  There used to
+** be a separate OP_VRowid opcode for use with virtual tables, but this
+** one opcode now works for both table types.
 */
 case OP_Rowid: {                 /* out2-prerelease */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bm */
   VdbeCursor *pC;
   i64 v;
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+#endif /* local variables moved into u.bm */
 
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  rc = sqlite3VdbeCursorMoveto(pC);
-  if( rc ) goto abort_due_to_error;
-  if( pC->rowidIsValid ){
-    v = pC->lastRowid;
-  }else if( pC->pseudoTable ){
-    v = keyToInt(pC->iKey);
-  }else if( pC->nullRow ){
-    /* Leave the rowid set to a NULL */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bm.pC = p->apCsr[pOp->p1];
+  assert( u.bm.pC!=0 );
+  assert( u.bm.pC->pseudoTableReg==0 );
+  if( u.bm.pC->nullRow ){
+    pOut->flags = MEM_Null;
     break;
+  }else if( u.bm.pC->deferredMoveto ){
+    u.bm.v = u.bm.pC->movetoTarget;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  }else if( u.bm.pC->pVtabCursor ){
+    u.bm.pVtab = u.bm.pC->pVtabCursor->pVtab;
+    u.bm.pModule = u.bm.pVtab->pModule;
+    assert( u.bm.pModule->xRowid );
+    rc = u.bm.pModule->xRowid(u.bm.pC->pVtabCursor, &u.bm.v);
+    importVtabErrMsg(p, u.bm.pVtab);
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
   }else{
-    assert( pC->pCursor!=0 );
-    sqlite3BtreeKeySize(pC->pCursor, &v);
-    v = keyToInt(v);
+    assert( u.bm.pC->pCursor!=0 );
+    rc = sqlite3VdbeCursorMoveto(u.bm.pC);
+    if( rc ) goto abort_due_to_error;
+    if( u.bm.pC->rowidIsValid ){
+      u.bm.v = u.bm.pC->lastRowid;
+    }else{
+      rc = sqlite3BtreeKeySize(u.bm.pC->pCursor, &u.bm.v);
+      assert( rc==SQLITE_OK );  /* Always so because of CursorMoveto() above */
+    }
   }
-  pOut->u.i = v;
-  MemSetTypeFlag(pOut, MEM_Int);
+  pOut->u.i = u.bm.v;
   break;
 }
 
@@ -52641,16 +67847,18 @@ case OP_Rowid: {                 /* out2-prerelease */
 ** write a NULL.
 */
 case OP_NullRow: {
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bn */
   VdbeCursor *pC;
+#endif /* local variables moved into u.bn */
 
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  pC->nullRow = 1;
-  pC->rowidIsValid = 0;
-  if( pC->pCursor ){
-    sqlite3BtreeClearCursor(pC->pCursor);
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bn.pC = p->apCsr[pOp->p1];
+  assert( u.bn.pC!=0 );
+  u.bn.pC->nullRow = 1;
+  u.bn.pC->rowidIsValid = 0;
+  assert( u.bn.pC->pCursor || u.bn.pC->pVtabCursor );
+  if( u.bn.pC->pCursor ){
+    sqlite3BtreeClearCursor(u.bn.pC->pCursor);
   }
   break;
 }
@@ -52664,22 +67872,25 @@ case OP_NullRow: {
 ** to the following instruction.
 */
 case OP_Last: {        /* jump */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bo */
   VdbeCursor *pC;
   BtCursor *pCrsr;
   int res;
+#endif /* local variables moved into u.bo */
 
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  pCrsr = pC->pCursor;
-  assert( pCrsr!=0 );
-  rc = sqlite3BtreeLast(pCrsr, &res);
-  pC->nullRow = (u8)res;
-  pC->deferredMoveto = 0;
-  pC->rowidIsValid = 0;
-  pC->cacheStatus = CACHE_STALE;
-  if( res && pOp->p2>0 ){
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bo.pC = p->apCsr[pOp->p1];
+  assert( u.bo.pC!=0 );
+  u.bo.pCrsr = u.bo.pC->pCursor;
+  u.bo.res = 0;
+  if( ALWAYS(u.bo.pCrsr!=0) ){
+    rc = sqlite3BtreeLast(u.bo.pCrsr, &u.bo.res);
+  }
+  u.bo.pC->nullRow = (u8)u.bo.res;
+  u.bo.pC->deferredMoveto = 0;
+  u.bo.pC->rowidIsValid = 0;
+  u.bo.pC->cacheStatus = CACHE_STALE;
+  if( pOp->p2>0 && u.bo.res ){
     pc = pOp->p2 - 1;
   }
   break;
@@ -52698,6 +67909,10 @@ case OP_Last: {        /* jump */
 ** regression tests can determine whether or not the optimizer is
 ** correctly optimizing out sorts.
 */
+case OP_SorterSort:    /* jump */
+#ifdef SQLITE_OMIT_MERGE_SORT
+  pOp->opcode = OP_Sort;
+#endif
 case OP_Sort: {        /* jump */
 #ifdef SQLITE_TEST
   sqlite3_sort_count++;
@@ -52715,32 +67930,37 @@ case OP_Sort: {        /* jump */
 ** to the following instruction.
 */
 case OP_Rewind: {        /* jump */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bp */
   VdbeCursor *pC;
   BtCursor *pCrsr;
   int res;
+#endif /* local variables moved into u.bp */
 
-  assert( i>=0 && i<p->nCursor );
-  pC = p->apCsr[i];
-  assert( pC!=0 );
-  if( (pCrsr = pC->pCursor)!=0 ){
-    rc = sqlite3BtreeFirst(pCrsr, &res);
-    pC->atFirst = res==0 ?1:0;
-    pC->deferredMoveto = 0;
-    pC->cacheStatus = CACHE_STALE;
-    pC->rowidIsValid = 0;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bp.pC = p->apCsr[pOp->p1];
+  assert( u.bp.pC!=0 );
+  assert( u.bp.pC->isSorter==(pOp->opcode==OP_SorterSort) );
+  u.bp.res = 1;
+  if( isSorter(u.bp.pC) ){
+    rc = sqlite3VdbeSorterRewind(db, u.bp.pC, &u.bp.res);
   }else{
-    res = 1;
+    u.bp.pCrsr = u.bp.pC->pCursor;
+    assert( u.bp.pCrsr );
+    rc = sqlite3BtreeFirst(u.bp.pCrsr, &u.bp.res);
+    u.bp.pC->atFirst = u.bp.res==0 ?1:0;
+    u.bp.pC->deferredMoveto = 0;
+    u.bp.pC->cacheStatus = CACHE_STALE;
+    u.bp.pC->rowidIsValid = 0;
   }
-  pC->nullRow = (u8)res;
+  u.bp.pC->nullRow = (u8)u.bp.res;
   assert( pOp->p2>0 && pOp->p2<p->nOp );
-  if( res ){
+  if( u.bp.res ){
     pc = pOp->p2 - 1;
   }
   break;
 }
 
-/* Opcode: Next P1 P2 * * *
+/* Opcode: Next P1 P2 * P4 P5
 **
 ** Advance cursor P1 so that it points to the next key/data pair in its
 ** table or index.  If there are no more key/value pairs then fall through
@@ -52749,9 +67969,15 @@ case OP_Rewind: {        /* jump */
 **
 ** The P1 cursor must be for a real table, not a pseudo-table.
 **
+** P4 is always of type P4_ADVANCE. The function pointer points to
+** sqlite3BtreeNext().
+**
+** If P5 is positive and the jump is taken, then event counter
+** number P5-1 in the prepared statement is incremented.
+**
 ** See also: Prev
 */
-/* Opcode: Prev P1 P2 * * *
+/* Opcode: Prev P1 P2 * * P5
 **
 ** Back up cursor P1 so that it points to the previous key/data pair in its
 ** table or index.  If there is no previous key/value pairs then fall through
@@ -52759,42 +67985,60 @@ case OP_Rewind: {        /* jump */
 ** jump immediately to P2.
 **
 ** The P1 cursor must be for a real table, not a pseudo-table.
+**
+** P4 is always of type P4_ADVANCE. The function pointer points to
+** sqlite3BtreePrevious().
+**
+** If P5 is positive and the jump is taken, then event counter
+** number P5-1 in the prepared statement is incremented.
 */
+case OP_SorterNext:    /* jump */
+#ifdef SQLITE_OMIT_MERGE_SORT
+  pOp->opcode = OP_Next;
+#endif
 case OP_Prev:          /* jump */
 case OP_Next: {        /* jump */
+#if 0  /* local variables moved into u.bq */
   VdbeCursor *pC;
-  BtCursor *pCrsr;
   int res;
+#endif /* local variables moved into u.bq */
 
   CHECK_FOR_INTERRUPT;
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
-  pC = p->apCsr[pOp->p1];
-  if( pC==0 ){
+  assert( pOp->p5<=ArraySize(p->aCounter) );
+  u.bq.pC = p->apCsr[pOp->p1];
+  if( u.bq.pC==0 ){
     break;  /* See ticket #2273 */
   }
-  pCrsr = pC->pCursor;
-  assert( pCrsr );
-  res = 1;
-  assert( pC->deferredMoveto==0 );
-  rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :
-                              sqlite3BtreePrevious(pCrsr, &res);
-  pC->nullRow = (u8)res;
-  pC->cacheStatus = CACHE_STALE;
-  if( res==0 ){
+  assert( u.bq.pC->isSorter==(pOp->opcode==OP_SorterNext) );
+  if( isSorter(u.bq.pC) ){
+    assert( pOp->opcode==OP_SorterNext );
+    rc = sqlite3VdbeSorterNext(db, u.bq.pC, &u.bq.res);
+  }else{
+    u.bq.res = 1;
+    assert( u.bq.pC->deferredMoveto==0 );
+    assert( u.bq.pC->pCursor );
+    assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
+    assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
+    rc = pOp->p4.xAdvance(u.bq.pC->pCursor, &u.bq.res);
+  }
+  u.bq.pC->nullRow = (u8)u.bq.res;
+  u.bq.pC->cacheStatus = CACHE_STALE;
+  if( u.bq.res==0 ){
     pc = pOp->p2 - 1;
     if( pOp->p5 ) p->aCounter[pOp->p5-1]++;
 #ifdef SQLITE_TEST
     sqlite3_search_count++;
 #endif
   }
-  pC->rowidIsValid = 0;
+  u.bq.pC->rowidIsValid = 0;
   break;
 }
 
-/* Opcode: IdxInsert P1 P2 P3 * *
+/* Opcode: IdxInsert P1 P2 P3 * P5
 **
-** Register P2 holds a SQL index key made using the
-** MakeIdxRec instructions.  This opcode writes that key
+** Register P2 holds an SQL index key made using the
+** MakeRecord instructions.  This opcode writes that key
 ** into the index P1.  Data for the entry is nil.
 **
 ** P3 is a flag that provides a hint to the b-tree layer that this
@@ -52803,22 +68047,40 @@ case OP_Next: {        /* jump */
 ** This instruction only works for indices.  The equivalent instruction
 ** for tables is OP_Insert.
 */
+case OP_SorterInsert:       /* in2 */
+#ifdef SQLITE_OMIT_MERGE_SORT
+  pOp->opcode = OP_IdxInsert;
+#endif
 case OP_IdxInsert: {        /* in2 */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.br */
   VdbeCursor *pC;
   BtCursor *pCrsr;
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
+  int nKey;
+  const char *zKey;
+#endif /* local variables moved into u.br */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.br.pC = p->apCsr[pOp->p1];
+  assert( u.br.pC!=0 );
+  assert( u.br.pC->isSorter==(pOp->opcode==OP_SorterInsert) );
+  pIn2 = &aMem[pOp->p2];
   assert( pIn2->flags & MEM_Blob );
-  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
-    assert( pC->isTable==0 );
+  u.br.pCrsr = u.br.pC->pCursor;
+  if( ALWAYS(u.br.pCrsr!=0) ){
+    assert( u.br.pC->isTable==0 );
     rc = ExpandBlob(pIn2);
     if( rc==SQLITE_OK ){
-      int nKey = pIn2->n;
-      const char *zKey = pIn2->z;
-      rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p3);
-      assert( pC->deferredMoveto==0 );
-      pC->cacheStatus = CACHE_STALE;
+      if( isSorter(u.br.pC) ){
+        rc = sqlite3VdbeSorterWrite(db, u.br.pC, pIn2);
+      }else{
+        u.br.nKey = pIn2->n;
+        u.br.zKey = pIn2->z;
+        rc = sqlite3BtreeInsert(u.br.pCrsr, u.br.zKey, u.br.nKey, "", 0, 0, pOp->p3,
+            ((pOp->p5 & OPFLAG_USESEEKRESULT) ? u.br.pC->seekResult : 0)
+            );
+        assert( u.br.pC->deferredMoveto==0 );
+        u.br.pC->cacheStatus = CACHE_STALE;
+      }
     }
   }
   break;
@@ -52831,26 +68093,33 @@ case OP_IdxInsert: {        /* in2 */
 ** index opened by cursor P1.
 */
 case OP_IdxDelete: {
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bs */
   VdbeCursor *pC;
   BtCursor *pCrsr;
+  int res;
+  UnpackedRecord r;
+#endif /* local variables moved into u.bs */
+
   assert( pOp->p3>0 );
-  assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem );
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
-  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
-    int res;
-    UnpackedRecord r;
-    r.pKeyInfo = pC->pKeyInfo;
-    r.nField = (u16)pOp->p3;
-    r.flags = 0;
-    r.aMem = &p->aMem[pOp->p2];
-    rc = sqlite3BtreeMovetoUnpacked(pCrsr, &r, 0, 0, &res);
-    if( rc==SQLITE_OK && res==0 ){
-      rc = sqlite3BtreeDelete(pCrsr);
+  assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem+1 );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bs.pC = p->apCsr[pOp->p1];
+  assert( u.bs.pC!=0 );
+  u.bs.pCrsr = u.bs.pC->pCursor;
+  if( ALWAYS(u.bs.pCrsr!=0) ){
+    u.bs.r.pKeyInfo = u.bs.pC->pKeyInfo;
+    u.bs.r.nField = (u16)pOp->p3;
+    u.bs.r.flags = 0;
+    u.bs.r.aMem = &aMem[pOp->p2];
+#ifdef SQLITE_DEBUG
+    { int i; for(i=0; i<u.bs.r.nField; i++) assert( memIsValid(&u.bs.r.aMem[i]) ); }
+#endif
+    rc = sqlite3BtreeMovetoUnpacked(u.bs.pCrsr, &u.bs.r, 0, 0, &u.bs.res);
+    if( rc==SQLITE_OK && u.bs.res==0 ){
+      rc = sqlite3BtreeDelete(u.bs.pCrsr);
     }
-    assert( pC->deferredMoveto==0 );
-    pC->cacheStatus = CACHE_STALE;
+    assert( u.bs.pC->deferredMoveto==0 );
+    u.bs.pC->cacheStatus = CACHE_STALE;
   }
   break;
 }
@@ -52861,27 +68130,32 @@ case OP_IdxDelete: {
 ** the end of the index key pointed to by cursor P1.  This integer should be
 ** the rowid of the table entry to which this index entry points.
 **
-** See also: Rowid, MakeIdxRec.
+** See also: Rowid, MakeRecord.
 */
 case OP_IdxRowid: {              /* out2-prerelease */
-  int i = pOp->p1;
+#if 0  /* local variables moved into u.bt */
   BtCursor *pCrsr;
   VdbeCursor *pC;
+  i64 rowid;
+#endif /* local variables moved into u.bt */
 
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
-  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
-    i64 rowid;
-
-    assert( pC->deferredMoveto==0 );
-    assert( pC->isTable==0 );
-    if( !pC->nullRow ){
-      rc = sqlite3VdbeIdxRowid(pCrsr, &rowid);
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bt.pC = p->apCsr[pOp->p1];
+  assert( u.bt.pC!=0 );
+  u.bt.pCrsr = u.bt.pC->pCursor;
+  pOut->flags = MEM_Null;
+  if( ALWAYS(u.bt.pCrsr!=0) ){
+    rc = sqlite3VdbeCursorMoveto(u.bt.pC);
+    if( NEVER(rc) ) goto abort_due_to_error;
+    assert( u.bt.pC->deferredMoveto==0 );
+    assert( u.bt.pC->isTable==0 );
+    if( !u.bt.pC->nullRow ){
+      rc = sqlite3VdbeIdxRowid(db, u.bt.pCrsr, &u.bt.rowid);
       if( rc!=SQLITE_OK ){
         goto abort_due_to_error;
       }
-      MemSetTypeFlag(pOut, MEM_Int);
-      pOut->u.i = rowid;
+      pOut->u.i = u.bt.rowid;
+      pOut->flags = MEM_Int;
     }
   }
   break;
@@ -52901,7 +68175,7 @@ case OP_IdxRowid: {              /* out2-prerelease */
 ** that if the key from register P3 is a prefix of the key in the cursor,
 ** the result is false whereas it would be true with IdxGT.
 */
-/* Opcode: IdxLT P1 P2 P3 * P5
+/* Opcode: IdxLT P1 P2 P3 P4 P5
 **
 ** The P4 register values beginning with P3 form an unpacked index 
 ** key that omits the ROWID.  Compare this key value against the index 
@@ -52913,35 +68187,41 @@ case OP_IdxRowid: {              /* out2-prerelease */
 ** If P5 is non-zero then the key value is increased by an epsilon prior 
 ** to the comparison.  This makes the opcode work like IdxLE.
 */
-case OP_IdxLT:          /* jump, in3 */
-case OP_IdxGE: {        /* jump, in3 */
-  int i= pOp->p1;
+case OP_IdxLT:          /* jump */
+case OP_IdxGE: {        /* jump */
+#if 0  /* local variables moved into u.bu */
   VdbeCursor *pC;
+  int res;
+  UnpackedRecord r;
+#endif /* local variables moved into u.bu */
 
-  assert( i>=0 && i<p->nCursor );
-  assert( p->apCsr[i]!=0 );
-  if( (pC = p->apCsr[i])->pCursor!=0 ){
-    int res;
-    UnpackedRecord r;
-    assert( pC->deferredMoveto==0 );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  u.bu.pC = p->apCsr[pOp->p1];
+  assert( u.bu.pC!=0 );
+  assert( u.bu.pC->isOrdered );
+  if( ALWAYS(u.bu.pC->pCursor!=0) ){
+    assert( u.bu.pC->deferredMoveto==0 );
     assert( pOp->p5==0 || pOp->p5==1 );
     assert( pOp->p4type==P4_INT32 );
-    r.pKeyInfo = pC->pKeyInfo;
-    r.nField = (u16)pOp->p4.i;
+    u.bu.r.pKeyInfo = u.bu.pC->pKeyInfo;
+    u.bu.r.nField = (u16)pOp->p4.i;
     if( pOp->p5 ){
-      r.flags = UNPACKED_INCRKEY | UNPACKED_IGNORE_ROWID;
+      u.bu.r.flags = UNPACKED_INCRKEY | UNPACKED_PREFIX_MATCH;
     }else{
-      r.flags = UNPACKED_IGNORE_ROWID;
+      u.bu.r.flags = UNPACKED_PREFIX_MATCH;
     }
-    r.aMem = &p->aMem[pOp->p3];
-    rc = sqlite3VdbeIdxKeyCompare(pC, &r, &res);
+    u.bu.r.aMem = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+    { int i; for(i=0; i<u.bu.r.nField; i++) assert( memIsValid(&u.bu.r.aMem[i]) ); }
+#endif
+    rc = sqlite3VdbeIdxKeyCompare(u.bu.pC, &u.bu.r, &u.bu.res);
     if( pOp->opcode==OP_IdxLT ){
-      res = -res;
+      u.bu.res = -u.bu.res;
     }else{
       assert( pOp->opcode==OP_IdxGE );
-      res++;
+      u.bu.res++;
     }
-    if( res>0 ){
+    if( u.bu.res>0 ){
       pc = pOp->p2 - 1 ;
     }
   }
@@ -52969,32 +68249,39 @@ case OP_IdxGE: {        /* jump, in3 */
 ** See also: Clear
 */
 case OP_Destroy: {     /* out2-prerelease */
+#if 0  /* local variables moved into u.bv */
   int iMoved;
   int iCnt;
-#ifndef SQLITE_OMIT_VIRTUALTABLE
   Vdbe *pVdbe;
-  iCnt = 0;
-  for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pNext){
-    if( pVdbe->magic==VDBE_MAGIC_RUN && pVdbe->inVtabMethod<2 && pVdbe->pc>=0 ){
-      iCnt++;
+  int iDb;
+#endif /* local variables moved into u.bv */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  u.bv.iCnt = 0;
+  for(u.bv.pVdbe=db->pVdbe; u.bv.pVdbe; u.bv.pVdbe = u.bv.pVdbe->pNext){
+    if( u.bv.pVdbe->magic==VDBE_MAGIC_RUN && u.bv.pVdbe->inVtabMethod<2 && u.bv.pVdbe->pc>=0 ){
+      u.bv.iCnt++;
     }
   }
 #else
-  iCnt = db->activeVdbeCnt;
+  u.bv.iCnt = db->activeVdbeCnt;
 #endif
-  if( iCnt>1 ){
+  pOut->flags = MEM_Null;
+  if( u.bv.iCnt>1 ){
     rc = SQLITE_LOCKED;
     p->errorAction = OE_Abort;
   }else{
-    int iDb = pOp->p3;
-    assert( iCnt==1 );
-    assert( (p->btreeMask & (1<<iDb))!=0 );
-    rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
-    MemSetTypeFlag(pOut, MEM_Int);
-    pOut->u.i = iMoved;
+    u.bv.iDb = pOp->p3;
+    assert( u.bv.iCnt==1 );
+    assert( (p->btreeMask & (((yDbMask)1)<<u.bv.iDb))!=0 );
+    rc = sqlite3BtreeDropTable(db->aDb[u.bv.iDb].pBt, pOp->p1, &u.bv.iMoved);
+    pOut->flags = MEM_Int;
+    pOut->u.i = u.bv.iMoved;
 #ifndef SQLITE_OMIT_AUTOVACUUM
-    if( rc==SQLITE_OK && iMoved!=0 ){
-      sqlite3RootPageMoved(&db->aDb[iDb], iMoved, pOp->p1);
+    if( rc==SQLITE_OK && u.bv.iMoved!=0 ){
+      sqlite3RootPageMoved(db, u.bv.iDb, u.bv.iMoved, pOp->p1);
+      /* All OP_Destroy operations occur on the same btree */
+      assert( resetSchemaOnFault==0 || resetSchemaOnFault==u.bv.iDb+1 );
+      resetSchemaOnFault = u.bv.iDb+1;
     }
 #endif
   }
@@ -53011,7 +68298,7 @@ case OP_Destroy: {     /* out2-prerelease */
 ** P2==1 then the table to be clear is in the auxiliary database file
 ** that is used to store tables create using CREATE TEMPORARY TABLE.
 **
-** If the P3 value is non-zero, then the table refered to must be an
+** If the P3 value is non-zero, then the table referred to must be an
 ** intkey table (an SQL table, not an index). In this case the row change 
 ** count is incremented by the number of rows in the table being cleared. 
 ** If P3 is greater than zero, then the value stored in register P3 is
@@ -53020,15 +68307,21 @@ case OP_Destroy: {     /* out2-prerelease */
 ** See also: Destroy
 */
 case OP_Clear: {
-  int nChange = 0;
-  assert( (p->btreeMask & (1<<pOp->p2))!=0 );
+#if 0  /* local variables moved into u.bw */
+  int nChange;
+#endif /* local variables moved into u.bw */
+
+  u.bw.nChange = 0;
+  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p2))!=0 );
   rc = sqlite3BtreeClearTable(
-      db->aDb[pOp->p2].pBt, pOp->p1, (pOp->p3 ? &nChange : 0)
+      db->aDb[pOp->p2].pBt, pOp->p1, (pOp->p3 ? &u.bw.nChange : 0)
   );
   if( pOp->p3 ){
-    p->nChange += nChange;
+    p->nChange += u.bw.nChange;
     if( pOp->p3>0 ){
-      p->aMem[pOp->p3].u.i += nChange;
+      assert( memIsValid(&aMem[pOp->p3]) );
+      memAboutToChange(p, &aMem[pOp->p3]);
+      aMem[pOp->p3].u.i += u.bw.nChange;
     }
   }
   break;
@@ -53058,72 +68351,86 @@ case OP_Clear: {
 */
 case OP_CreateIndex:            /* out2-prerelease */
 case OP_CreateTable: {          /* out2-prerelease */
-  int pgno = 0;
+#if 0  /* local variables moved into u.bx */
+  int pgno;
   int flags;
   Db *pDb;
+#endif /* local variables moved into u.bx */
+
+  u.bx.pgno = 0;
   assert( pOp->p1>=0 && pOp->p1<db->nDb );
-  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
-  pDb = &db->aDb[pOp->p1];
-  assert( pDb->pBt!=0 );
+  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
+  u.bx.pDb = &db->aDb[pOp->p1];
+  assert( u.bx.pDb->pBt!=0 );
   if( pOp->opcode==OP_CreateTable ){
-    /* flags = BTREE_INTKEY; */
-    flags = BTREE_LEAFDATA|BTREE_INTKEY;
+    /* u.bx.flags = BTREE_INTKEY; */
+    u.bx.flags = BTREE_INTKEY;
   }else{
-    flags = BTREE_ZERODATA;
+    u.bx.flags = BTREE_BLOBKEY;
   }
-  rc = sqlite3BtreeCreateTable(pDb->pBt, &pgno, flags);
-  pOut->u.i = pgno;
-  MemSetTypeFlag(pOut, MEM_Int);
+  rc = sqlite3BtreeCreateTable(u.bx.pDb->pBt, &u.bx.pgno, u.bx.flags);
+  pOut->u.i = u.bx.pgno;
   break;
 }
 
-/* Opcode: ParseSchema P1 P2 * P4 *
+/* Opcode: ParseSchema P1 * * P4 *
 **
 ** Read and parse all entries from the SQLITE_MASTER table of database P1
-** that match the WHERE clause P4.  P2 is the "force" flag.   Always do
-** the parsing if P2 is true.  If P2 is false, then this routine is a
-** no-op if the schema is not currently loaded.  In other words, if P2
-** is false, the SQLITE_MASTER table is only parsed if the rest of the
-** schema is already loaded into the symbol table.
+** that match the WHERE clause P4. 
 **
 ** This opcode invokes the parser to create a new virtual machine,
 ** then runs the new virtual machine.  It is thus a re-entrant opcode.
 */
 case OP_ParseSchema: {
-  char *zSql;
-  int iDb = pOp->p1;
+#if 0  /* local variables moved into u.by */
+  int iDb;
   const char *zMaster;
+  char *zSql;
   InitData initData;
+#endif /* local variables moved into u.by */
 
-  assert( iDb>=0 && iDb<db->nDb );
-  if( !pOp->p2 && !DbHasProperty(db, iDb, DB_SchemaLoaded) ){
-    break;
+  /* Any prepared statement that invokes this opcode will hold mutexes
+  ** on every btree.  This is a prerequisite for invoking
+  ** sqlite3InitCallback().
+  */
+#ifdef SQLITE_DEBUG
+  for(u.by.iDb=0; u.by.iDb<db->nDb; u.by.iDb++){
+    assert( u.by.iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[u.by.iDb].pBt) );
   }
-  zMaster = SCHEMA_TABLE(iDb);
-  initData.db = db;
-  initData.iDb = pOp->p1;
-  initData.pzErrMsg = &p->zErrMsg;
-  zSql = sqlite3MPrintf(db,
-     "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s",
-     db->aDb[iDb].zName, zMaster, pOp->p4.z);
-  if( zSql==0 ) goto no_mem;
-  (void)sqlite3SafetyOff(db);
-  assert( db->init.busy==0 );
-  db->init.busy = 1;
-  initData.rc = SQLITE_OK;
-  assert( !db->mallocFailed );
-  rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
-  if( rc==SQLITE_OK ) rc = initData.rc;
-  sqlite3DbFree(db, zSql);
-  db->init.busy = 0;
-  (void)sqlite3SafetyOn(db);
+#endif
+
+  u.by.iDb = pOp->p1;
+  assert( u.by.iDb>=0 && u.by.iDb<db->nDb );
+  assert( DbHasProperty(db, u.by.iDb, DB_SchemaLoaded) );
+  /* Used to be a conditional */ {
+    u.by.zMaster = SCHEMA_TABLE(u.by.iDb);
+    u.by.initData.db = db;
+    u.by.initData.iDb = pOp->p1;
+    u.by.initData.pzErrMsg = &p->zErrMsg;
+    u.by.zSql = sqlite3MPrintf(db,
+       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
+       db->aDb[u.by.iDb].zName, u.by.zMaster, pOp->p4.z);
+    if( u.by.zSql==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      assert( db->init.busy==0 );
+      db->init.busy = 1;
+      u.by.initData.rc = SQLITE_OK;
+      assert( !db->mallocFailed );
+      rc = sqlite3_exec(db, u.by.zSql, sqlite3InitCallback, &u.by.initData, 0);
+      if( rc==SQLITE_OK ) rc = u.by.initData.rc;
+      sqlite3DbFree(db, u.by.zSql);
+      db->init.busy = 0;
+    }
+  }
+  if( rc ) sqlite3ResetAllSchemasOfConnection(db);
   if( rc==SQLITE_NOMEM ){
     goto no_mem;
   }
-  break;  
+  break;
 }
 
-#if !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)
+#if !defined(SQLITE_OMIT_ANALYZE)
 /* Opcode: LoadAnalysis P1 * * * *
 **
 ** Read the sqlite_stat1 table for database P1 and load the content
@@ -53131,12 +68438,11 @@ case OP_ParseSchema: {
 ** the analysis to be used when preparing all subsequent queries.
 */
 case OP_LoadAnalysis: {
-  int iDb = pOp->p1;
-  assert( iDb>=0 && iDb<db->nDb );
-  rc = sqlite3AnalysisLoad(db, iDb);
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  rc = sqlite3AnalysisLoad(db, pOp->p1);
   break;  
 }
-#endif /* !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)  */
+#endif /* !defined(SQLITE_OMIT_ANALYZE) */
 
 /* Opcode: DropTable P1 * * P4 *
 **
@@ -53197,39 +68503,41 @@ case OP_DropTrigger: {
 ** This opcode is used to implement the integrity_check pragma.
 */
 case OP_IntegrityCk: {
+#if 0  /* local variables moved into u.bz */
   int nRoot;      /* Number of tables to check.  (Number of root pages.) */
   int *aRoot;     /* Array of rootpage numbers for tables to be checked */
   int j;          /* Loop counter */
   int nErr;       /* Number of errors reported */
   char *z;        /* Text of the error report */
   Mem *pnErr;     /* Register keeping track of errors remaining */
-  
-  nRoot = pOp->p2;
-  assert( nRoot>0 );
-  aRoot = sqlite3DbMallocRaw(db, sizeof(int)*(nRoot+1) );
-  if( aRoot==0 ) goto no_mem;
+#endif /* local variables moved into u.bz */
+
+  u.bz.nRoot = pOp->p2;
+  assert( u.bz.nRoot>0 );
+  u.bz.aRoot = sqlite3DbMallocRaw(db, sizeof(int)*(u.bz.nRoot+1) );
+  if( u.bz.aRoot==0 ) goto no_mem;
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  pnErr = &p->aMem[pOp->p3];
-  assert( (pnErr->flags & MEM_Int)!=0 );
-  assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
-  pIn1 = &p->aMem[pOp->p1];
-  for(j=0; j<nRoot; j++){
-    aRoot[j] = (int)sqlite3VdbeIntValue(&pIn1[j]);
+  u.bz.pnErr = &aMem[pOp->p3];
+  assert( (u.bz.pnErr->flags & MEM_Int)!=0 );
+  assert( (u.bz.pnErr->flags & (MEM_Str|MEM_Blob))==0 );
+  pIn1 = &aMem[pOp->p1];
+  for(u.bz.j=0; u.bz.j<u.bz.nRoot; u.bz.j++){
+    u.bz.aRoot[u.bz.j] = (int)sqlite3VdbeIntValue(&pIn1[u.bz.j]);
   }
-  aRoot[j] = 0;
+  u.bz.aRoot[u.bz.j] = 0;
   assert( pOp->p5<db->nDb );
-  assert( (p->btreeMask & (1<<pOp->p5))!=0 );
-  z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p5].pBt, aRoot, nRoot,
-                                 (int)pnErr->u.i, &nErr);
-  sqlite3DbFree(db, aRoot);
-  pnErr->u.i -= nErr;
+  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p5))!=0 );
+  u.bz.z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p5].pBt, u.bz.aRoot, u.bz.nRoot,
+                                 (int)u.bz.pnErr->u.i, &u.bz.nErr);
+  sqlite3DbFree(db, u.bz.aRoot);
+  u.bz.pnErr->u.i -= u.bz.nErr;
   sqlite3VdbeMemSetNull(pIn1);
-  if( nErr==0 ){
-    assert( z==0 );
-  }else if( z==0 ){
+  if( u.bz.nErr==0 ){
+    assert( u.bz.z==0 );
+  }else if( u.bz.z==0 ){
     goto no_mem;
   }else{
-    sqlite3VdbeMemSetStr(pIn1, z, -1, SQLITE_UTF8, sqlite3_free);
+    sqlite3VdbeMemSetStr(pIn1, u.bz.z, -1, SQLITE_UTF8, sqlite3_free);
   }
   UPDATE_MAX_BLOBSIZE(pIn1);
   sqlite3VdbeChangeEncoding(pIn1, encoding);
@@ -53244,19 +68552,15 @@ case OP_IntegrityCk: {
 **
 ** An assertion fails if P2 is not an integer.
 */
-case OP_RowSetAdd: {       /* in2 */
-  Mem *pIdx;
-  Mem *pVal;
-  assert( pOp->p1>0 && pOp->p1<=p->nMem );
-  pIdx = &p->aMem[pOp->p1];
-  assert( pOp->p2>0 && pOp->p2<=p->nMem );
-  pVal = &p->aMem[pOp->p2];
-  assert( (pVal->flags & MEM_Int)!=0 );
-  if( (pIdx->flags & MEM_RowSet)==0 ){
-    sqlite3VdbeMemSetRowSet(pIdx);
-    if( (pIdx->flags & MEM_RowSet)==0 ) goto no_mem;
+case OP_RowSetAdd: {       /* in1, in2 */
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  assert( (pIn2->flags & MEM_Int)!=0 );
+  if( (pIn1->flags & MEM_RowSet)==0 ){
+    sqlite3VdbeMemSetRowSet(pIn1);
+    if( (pIn1->flags & MEM_RowSet)==0 ) goto no_mem;
   }
-  sqlite3RowSetInsert(pIdx->u.pRowSet, pVal->u.i);
+  sqlite3RowSetInsert(pIn1->u.pRowSet, pIn2->u.i);
   break;
 }
 
@@ -53266,82 +68570,299 @@ case OP_RowSetAdd: {       /* in2 */
 ** register P3.  Or, if boolean index P1 is initially empty, leave P3
 ** unchanged and jump to instruction P2.
 */
-case OP_RowSetRead: {       /* jump, out3 */
-  Mem *pIdx;
+case OP_RowSetRead: {       /* jump, in1, out3 */
+#if 0  /* local variables moved into u.ca */
   i64 val;
-  assert( pOp->p1>0 && pOp->p1<=p->nMem );
+#endif /* local variables moved into u.ca */
   CHECK_FOR_INTERRUPT;
-  pIdx = &p->aMem[pOp->p1];
-  pOut = &p->aMem[pOp->p3];
-  if( (pIdx->flags & MEM_RowSet)==0 
-   || sqlite3RowSetNext(pIdx->u.pRowSet, &val)==0
+  pIn1 = &aMem[pOp->p1];
+  if( (pIn1->flags & MEM_RowSet)==0
+   || sqlite3RowSetNext(pIn1->u.pRowSet, &u.ca.val)==0
   ){
     /* The boolean index is empty */
-    sqlite3VdbeMemSetNull(pIdx);
+    sqlite3VdbeMemSetNull(pIn1);
     pc = pOp->p2 - 1;
   }else{
     /* A value was pulled from the index */
-    assert( pOp->p3>0 && pOp->p3<=p->nMem );
-    sqlite3VdbeMemSetInt64(pOut, val);
+    sqlite3VdbeMemSetInt64(&aMem[pOp->p3], u.ca.val);
+  }
+  break;
+}
+
+/* Opcode: RowSetTest P1 P2 P3 P4
+**
+** Register P3 is assumed to hold a 64-bit integer value. If register P1
+** contains a RowSet object and that RowSet object contains
+** the value held in P3, jump to register P2. Otherwise, insert the
+** integer in P3 into the RowSet and continue on to the
+** next opcode.
+**
+** The RowSet object is optimized for the case where successive sets
+** of integers, where each set contains no duplicates. Each set
+** of values is identified by a unique P4 value. The first set
+** must have P4==0, the final set P4=-1.  P4 must be either -1 or
+** non-negative.  For non-negative values of P4 only the lower 4
+** bits are significant.
+**
+** This allows optimizations: (a) when P4==0 there is no need to test
+** the rowset object for P3, as it is guaranteed not to contain it,
+** (b) when P4==-1 there is no need to insert the value, as it will
+** never be tested for, and (c) when a value that is part of set X is
+** inserted, there is no need to search to see if the same value was
+** previously inserted as part of set X (only if it was previously
+** inserted as part of some other set).
+*/
+case OP_RowSetTest: {                     /* jump, in1, in3 */
+#if 0  /* local variables moved into u.cb */
+  int iSet;
+  int exists;
+#endif /* local variables moved into u.cb */
+
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  u.cb.iSet = pOp->p4.i;
+  assert( pIn3->flags&MEM_Int );
+
+  /* If there is anything other than a rowset object in memory cell P1,
+  ** delete it now and initialize P1 with an empty rowset
+  */
+  if( (pIn1->flags & MEM_RowSet)==0 ){
+    sqlite3VdbeMemSetRowSet(pIn1);
+    if( (pIn1->flags & MEM_RowSet)==0 ) goto no_mem;
+  }
+
+  assert( pOp->p4type==P4_INT32 );
+  assert( u.cb.iSet==-1 || u.cb.iSet>=0 );
+  if( u.cb.iSet ){
+    u.cb.exists = sqlite3RowSetTest(pIn1->u.pRowSet,
+                               (u8)(u.cb.iSet>=0 ? u.cb.iSet & 0xf : 0xff),
+                               pIn3->u.i);
+    if( u.cb.exists ){
+      pc = pOp->p2 - 1;
+      break;
+    }
+  }
+  if( u.cb.iSet>=0 ){
+    sqlite3RowSetInsert(pIn1->u.pRowSet, pIn3->u.i);
   }
   break;
 }
 
 
 #ifndef SQLITE_OMIT_TRIGGER
-/* Opcode: ContextPush * * * 
-**
-** Save the current Vdbe context such that it can be restored by a ContextPop
-** opcode. The context stores the last insert row id, the last statement change
-** count, and the current statement change count.
-*/
-case OP_ContextPush: {
-  int i = p->contextStackTop++;
-  Context *pContext;
 
-  assert( i>=0 );
-  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
-  if( i>=p->contextStackDepth ){
-    p->contextStackDepth = i+1;
-    p->contextStack = sqlite3DbReallocOrFree(db, p->contextStack,
-                                          sizeof(Context)*(i+1));
-    if( p->contextStack==0 ) goto no_mem;
+/* Opcode: Program P1 P2 P3 P4 *
+**
+** Execute the trigger program passed as P4 (type P4_SUBPROGRAM). 
+**
+** P1 contains the address of the memory cell that contains the first memory 
+** cell in an array of values used as arguments to the sub-program. P2 
+** contains the address to jump to if the sub-program throws an IGNORE 
+** exception using the RAISE() function. Register P3 contains the address 
+** of a memory cell in this (the parent) VM that is used to allocate the 
+** memory required by the sub-vdbe at runtime.
+**
+** P4 is a pointer to the VM containing the trigger program.
+*/
+case OP_Program: {        /* jump */
+#if 0  /* local variables moved into u.cc */
+  int nMem;               /* Number of memory registers for sub-program */
+  int nByte;              /* Bytes of runtime space required for sub-program */
+  Mem *pRt;               /* Register to allocate runtime space */
+  Mem *pMem;              /* Used to iterate through memory cells */
+  Mem *pEnd;              /* Last memory cell in new array */
+  VdbeFrame *pFrame;      /* New vdbe frame to execute in */
+  SubProgram *pProgram;   /* Sub-program to execute */
+  void *t;                /* Token identifying trigger */
+#endif /* local variables moved into u.cc */
+
+  u.cc.pProgram = pOp->p4.pProgram;
+  u.cc.pRt = &aMem[pOp->p3];
+  assert( u.cc.pProgram->nOp>0 );
+
+  /* If the p5 flag is clear, then recursive invocation of triggers is
+  ** disabled for backwards compatibility (p5 is set if this sub-program
+  ** is really a trigger, not a foreign key action, and the flag set
+  ** and cleared by the "PRAGMA recursive_triggers" command is clear).
+  **
+  ** It is recursive invocation of triggers, at the SQL level, that is
+  ** disabled. In some cases a single trigger may generate more than one
+  ** SubProgram (if the trigger may be executed with more than one different
+  ** ON CONFLICT algorithm). SubProgram structures associated with a
+  ** single trigger all have the same value for the SubProgram.token
+  ** variable.  */
+  if( pOp->p5 ){
+    u.cc.t = u.cc.pProgram->token;
+    for(u.cc.pFrame=p->pFrame; u.cc.pFrame && u.cc.pFrame->token!=u.cc.t; u.cc.pFrame=u.cc.pFrame->pParent);
+    if( u.cc.pFrame ) break;
   }
-  pContext = &p->contextStack[i];
-  pContext->lastRowid = db->lastRowid;
-  pContext->nChange = p->nChange;
+
+  if( p->nFrame>=db->aLimit[SQLITE_LIMIT_TRIGGER_DEPTH] ){
+    rc = SQLITE_ERROR;
+    sqlite3SetString(&p->zErrMsg, db, "too many levels of trigger recursion");
+    break;
+  }
+
+  /* Register u.cc.pRt is used to store the memory required to save the state
+  ** of the current program, and the memory required at runtime to execute
+  ** the trigger program. If this trigger has been fired before, then u.cc.pRt
+  ** is already allocated. Otherwise, it must be initialized.  */
+  if( (u.cc.pRt->flags&MEM_Frame)==0 ){
+    /* SubProgram.nMem is set to the number of memory cells used by the
+    ** program stored in SubProgram.aOp. As well as these, one memory
+    ** cell is required for each cursor used by the program. Set local
+    ** variable u.cc.nMem (and later, VdbeFrame.nChildMem) to this value.
+    */
+    u.cc.nMem = u.cc.pProgram->nMem + u.cc.pProgram->nCsr;
+    u.cc.nByte = ROUND8(sizeof(VdbeFrame))
+              + u.cc.nMem * sizeof(Mem)
+              + u.cc.pProgram->nCsr * sizeof(VdbeCursor *)
+              + u.cc.pProgram->nOnce * sizeof(u8);
+    u.cc.pFrame = sqlite3DbMallocZero(db, u.cc.nByte);
+    if( !u.cc.pFrame ){
+      goto no_mem;
+    }
+    sqlite3VdbeMemRelease(u.cc.pRt);
+    u.cc.pRt->flags = MEM_Frame;
+    u.cc.pRt->u.pFrame = u.cc.pFrame;
+
+    u.cc.pFrame->v = p;
+    u.cc.pFrame->nChildMem = u.cc.nMem;
+    u.cc.pFrame->nChildCsr = u.cc.pProgram->nCsr;
+    u.cc.pFrame->pc = pc;
+    u.cc.pFrame->aMem = p->aMem;
+    u.cc.pFrame->nMem = p->nMem;
+    u.cc.pFrame->apCsr = p->apCsr;
+    u.cc.pFrame->nCursor = p->nCursor;
+    u.cc.pFrame->aOp = p->aOp;
+    u.cc.pFrame->nOp = p->nOp;
+    u.cc.pFrame->token = u.cc.pProgram->token;
+    u.cc.pFrame->aOnceFlag = p->aOnceFlag;
+    u.cc.pFrame->nOnceFlag = p->nOnceFlag;
+
+    u.cc.pEnd = &VdbeFrameMem(u.cc.pFrame)[u.cc.pFrame->nChildMem];
+    for(u.cc.pMem=VdbeFrameMem(u.cc.pFrame); u.cc.pMem!=u.cc.pEnd; u.cc.pMem++){
+      u.cc.pMem->flags = MEM_Invalid;
+      u.cc.pMem->db = db;
+    }
+  }else{
+    u.cc.pFrame = u.cc.pRt->u.pFrame;
+    assert( u.cc.pProgram->nMem+u.cc.pProgram->nCsr==u.cc.pFrame->nChildMem );
+    assert( u.cc.pProgram->nCsr==u.cc.pFrame->nChildCsr );
+    assert( pc==u.cc.pFrame->pc );
+  }
+
+  p->nFrame++;
+  u.cc.pFrame->pParent = p->pFrame;
+  u.cc.pFrame->lastRowid = lastRowid;
+  u.cc.pFrame->nChange = p->nChange;
+  p->nChange = 0;
+  p->pFrame = u.cc.pFrame;
+  p->aMem = aMem = &VdbeFrameMem(u.cc.pFrame)[-1];
+  p->nMem = u.cc.pFrame->nChildMem;
+  p->nCursor = (u16)u.cc.pFrame->nChildCsr;
+  p->apCsr = (VdbeCursor **)&aMem[p->nMem+1];
+  p->aOp = aOp = u.cc.pProgram->aOp;
+  p->nOp = u.cc.pProgram->nOp;
+  p->aOnceFlag = (u8 *)&p->apCsr[p->nCursor];
+  p->nOnceFlag = u.cc.pProgram->nOnce;
+  pc = -1;
+  memset(p->aOnceFlag, 0, p->nOnceFlag);
+
   break;
 }
 
-/* Opcode: ContextPop * * * 
+/* Opcode: Param P1 P2 * * *
 **
-** Restore the Vdbe context to the state it was in when contextPush was last
-** executed. The context stores the last insert row id, the last statement
-** change count, and the current statement change count.
+** This opcode is only ever present in sub-programs called via the 
+** OP_Program instruction. Copy a value currently stored in a memory 
+** cell of the calling (parent) frame to cell P2 in the current frames 
+** address space. This is used by trigger programs to access the new.* 
+** and old.* values.
+**
+** The address of the cell in the parent frame is determined by adding
+** the value of the P1 argument to the value of the P1 argument to the
+** calling OP_Program instruction.
 */
-case OP_ContextPop: {
-  Context *pContext = &p->contextStack[--p->contextStackTop];
-  assert( p->contextStackTop>=0 );
-  db->lastRowid = pContext->lastRowid;
-  p->nChange = pContext->nChange;
+case OP_Param: {           /* out2-prerelease */
+#if 0  /* local variables moved into u.cd */
+  VdbeFrame *pFrame;
+  Mem *pIn;
+#endif /* local variables moved into u.cd */
+  u.cd.pFrame = p->pFrame;
+  u.cd.pIn = &u.cd.pFrame->aMem[pOp->p1 + u.cd.pFrame->aOp[u.cd.pFrame->pc].p1];
+  sqlite3VdbeMemShallowCopy(pOut, u.cd.pIn, MEM_Ephem);
   break;
 }
+
 #endif /* #ifndef SQLITE_OMIT_TRIGGER */
 
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+/* Opcode: FkCounter P1 P2 * * *
+**
+** Increment a "constraint counter" by P2 (P2 may be negative or positive).
+** If P1 is non-zero, the database constraint counter is incremented 
+** (deferred foreign key constraints). Otherwise, if P1 is zero, the 
+** statement counter is incremented (immediate foreign key constraints).
+*/
+case OP_FkCounter: {
+  if( pOp->p1 ){
+    db->nDeferredCons += pOp->p2;
+  }else{
+    p->nFkConstraint += pOp->p2;
+  }
+  break;
+}
+
+/* Opcode: FkIfZero P1 P2 * * *
+**
+** This opcode tests if a foreign key constraint-counter is currently zero.
+** If so, jump to instruction P2. Otherwise, fall through to the next 
+** instruction.
+**
+** If P1 is non-zero, then the jump is taken if the database constraint-counter
+** is zero (the one that counts deferred constraint violations). If P1 is
+** zero, the jump is taken if the statement constraint-counter is zero
+** (immediate foreign key constraint violations).
+*/
+case OP_FkIfZero: {         /* jump */
+  if( pOp->p1 ){
+    if( db->nDeferredCons==0 ) pc = pOp->p2-1;
+  }else{
+    if( p->nFkConstraint==0 ) pc = pOp->p2-1;
+  }
+  break;
+}
+#endif /* #ifndef SQLITE_OMIT_FOREIGN_KEY */
+
 #ifndef SQLITE_OMIT_AUTOINCREMENT
 /* Opcode: MemMax P1 P2 * * *
 **
-** Set the value of register P1 to the maximum of its current value
-** and the value in register P2.
+** P1 is a register in the root frame of this VM (the root frame is
+** different from the current frame if this instruction is being executed
+** within a sub-program). Set the value of register P1 to the maximum of 
+** its current value and the value in register P2.
 **
 ** This instruction throws an error if the memory cell is not initially
 ** an integer.
 */
-case OP_MemMax: {        /* in1, in2 */
-  sqlite3VdbeMemIntegerify(pIn1);
+case OP_MemMax: {        /* in2 */
+#if 0  /* local variables moved into u.ce */
+  Mem *pIn1;
+  VdbeFrame *pFrame;
+#endif /* local variables moved into u.ce */
+  if( p->pFrame ){
+    for(u.ce.pFrame=p->pFrame; u.ce.pFrame->pParent; u.ce.pFrame=u.ce.pFrame->pParent);
+    u.ce.pIn1 = &u.ce.pFrame->aMem[pOp->p1];
+  }else{
+    u.ce.pIn1 = &aMem[pOp->p1];
+  }
+  assert( memIsValid(u.ce.pIn1) );
+  sqlite3VdbeMemIntegerify(u.ce.pIn1);
+  pIn2 = &aMem[pOp->p2];
   sqlite3VdbeMemIntegerify(pIn2);
-  if( pIn1->u.i<pIn2->u.i){
-    pIn1->u.i = pIn2->u.i;
+  if( u.ce.pIn1->u.i<pIn2->u.i){
+    u.ce.pIn1->u.i = pIn2->u.i;
   }
   break;
 }
@@ -53355,6 +68876,7 @@ case OP_MemMax: {        /* in1, in2 */
 ** not contain an integer.  An assertion fault will result if you try.
 */
 case OP_IfPos: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
   if( pIn1->u.i>0 ){
      pc = pOp->p2 - 1;
@@ -53370,6 +68892,7 @@ case OP_IfPos: {        /* jump, in1 */
 ** not contain an integer.  An assertion fault will result if you try.
 */
 case OP_IfNeg: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
   if( pIn1->u.i<0 ){
      pc = pOp->p2 - 1;
@@ -53377,15 +68900,18 @@ case OP_IfNeg: {        /* jump, in1 */
   break;
 }
 
-/* Opcode: IfZero P1 P2 * * *
+/* Opcode: IfZero P1 P2 P3 * *
 **
-** If the value of register P1 is exactly 0, jump to P2. 
+** The register P1 must contain an integer.  Add literal P3 to the
+** value in register P1.  If the result is exactly 0, jump to P2. 
 **
 ** It is illegal to use this instruction on a register that does
 ** not contain an integer.  An assertion fault will result if you try.
 */
 case OP_IfZero: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
+  pIn1->u.i += pOp->p3;
   if( pIn1->u.i==0 ){
      pc = pOp->p2 - 1;
   }
@@ -53403,43 +68929,57 @@ case OP_IfZero: {        /* jump, in1 */
 ** successors.
 */
 case OP_AggStep: {
-  int n = pOp->p5;
+#if 0  /* local variables moved into u.cf */
+  int n;
   int i;
-  Mem *pMem, *pRec;
+  Mem *pMem;
+  Mem *pRec;
   sqlite3_context ctx;
   sqlite3_value **apVal;
+#endif /* local variables moved into u.cf */
 
-  assert( n>=0 );
-  pRec = &p->aMem[pOp->p2];
-  apVal = p->apArg;
-  assert( apVal || n==0 );
-  for(i=0; i<n; i++, pRec++){
-    apVal[i] = pRec;
-    storeTypeInfo(pRec, encoding);
+  u.cf.n = pOp->p5;
+  assert( u.cf.n>=0 );
+  u.cf.pRec = &aMem[pOp->p2];
+  u.cf.apVal = p->apArg;
+  assert( u.cf.apVal || u.cf.n==0 );
+  for(u.cf.i=0; u.cf.i<u.cf.n; u.cf.i++, u.cf.pRec++){
+    assert( memIsValid(u.cf.pRec) );
+    u.cf.apVal[u.cf.i] = u.cf.pRec;
+    memAboutToChange(p, u.cf.pRec);
+    sqlite3VdbeMemStoreType(u.cf.pRec);
   }
-  ctx.pFunc = pOp->p4.pFunc;
+  u.cf.ctx.pFunc = pOp->p4.pFunc;
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  ctx.pMem = pMem = &p->aMem[pOp->p3];
-  pMem->n++;
-  ctx.s.flags = MEM_Null;
-  ctx.s.z = 0;
-  ctx.s.zMalloc = 0;
-  ctx.s.xDel = 0;
-  ctx.s.db = db;
-  ctx.isError = 0;
-  ctx.pColl = 0;
-  if( ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
+  u.cf.ctx.pMem = u.cf.pMem = &aMem[pOp->p3];
+  u.cf.pMem->n++;
+  u.cf.ctx.s.flags = MEM_Null;
+  u.cf.ctx.s.z = 0;
+  u.cf.ctx.s.zMalloc = 0;
+  u.cf.ctx.s.xDel = 0;
+  u.cf.ctx.s.db = db;
+  u.cf.ctx.isError = 0;
+  u.cf.ctx.pColl = 0;
+  u.cf.ctx.skipFlag = 0;
+  if( u.cf.ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
     assert( pOp>p->aOp );
     assert( pOp[-1].p4type==P4_COLLSEQ );
     assert( pOp[-1].opcode==OP_CollSeq );
-    ctx.pColl = pOp[-1].p4.pColl;
+    u.cf.ctx.pColl = pOp[-1].p4.pColl;
   }
-  (ctx.pFunc->xStep)(&ctx, n, apVal);
-  if( ctx.isError ){
-    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&ctx.s));
-    rc = ctx.isError;
+  (u.cf.ctx.pFunc->xStep)(&u.cf.ctx, u.cf.n, u.cf.apVal); /* IMP: R-24505-23230 */
+  if( u.cf.ctx.isError ){
+    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&u.cf.ctx.s));
+    rc = u.cf.ctx.isError;
   }
-  sqlite3VdbeMemRelease(&ctx.s);
+  if( u.cf.ctx.skipFlag ){
+    assert( pOp[-1].opcode==OP_CollSeq );
+    u.cf.i = pOp[-1].p1;
+    if( u.cf.i ) sqlite3VdbeMemSetInt64(&aMem[u.cf.i], 1);
+  }
+
+  sqlite3VdbeMemRelease(&u.cf.ctx.s);
+
   break;
 }
 
@@ -53456,22 +68996,165 @@ case OP_AggStep: {
 ** the step function was not previously called.
 */
 case OP_AggFinal: {
+#if 0  /* local variables moved into u.cg */
   Mem *pMem;
+#endif /* local variables moved into u.cg */
   assert( pOp->p1>0 && pOp->p1<=p->nMem );
-  pMem = &p->aMem[pOp->p1];
-  assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
-  rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);
-  if( rc==SQLITE_ERROR ){
-    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(pMem));
+  u.cg.pMem = &aMem[pOp->p1];
+  assert( (u.cg.pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
+  rc = sqlite3VdbeMemFinalize(u.cg.pMem, pOp->p4.pFunc);
+  if( rc ){
+    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(u.cg.pMem));
   }
-  sqlite3VdbeChangeEncoding(pMem, encoding);
-  UPDATE_MAX_BLOBSIZE(pMem);
-  if( sqlite3VdbeMemTooBig(pMem) ){
+  sqlite3VdbeChangeEncoding(u.cg.pMem, encoding);
+  UPDATE_MAX_BLOBSIZE(u.cg.pMem);
+  if( sqlite3VdbeMemTooBig(u.cg.pMem) ){
     goto too_big;
   }
   break;
 }
 
+#ifndef SQLITE_OMIT_WAL
+/* Opcode: Checkpoint P1 P2 P3 * *
+**
+** Checkpoint database P1. This is a no-op if P1 is not currently in
+** WAL mode. Parameter P2 is one of SQLITE_CHECKPOINT_PASSIVE, FULL
+** or RESTART.  Write 1 or 0 into mem[P3] if the checkpoint returns
+** SQLITE_BUSY or not, respectively.  Write the number of pages in the
+** WAL after the checkpoint into mem[P3+1] and the number of pages
+** in the WAL that have been checkpointed after the checkpoint
+** completes into mem[P3+2].  However on an error, mem[P3+1] and
+** mem[P3+2] are initialized to -1.
+*/
+case OP_Checkpoint: {
+#if 0  /* local variables moved into u.ch */
+  int i;                          /* Loop counter */
+  int aRes[3];                    /* Results */
+  Mem *pMem;                      /* Write results here */
+#endif /* local variables moved into u.ch */
+
+  u.ch.aRes[0] = 0;
+  u.ch.aRes[1] = u.ch.aRes[2] = -1;
+  assert( pOp->p2==SQLITE_CHECKPOINT_PASSIVE
+       || pOp->p2==SQLITE_CHECKPOINT_FULL
+       || pOp->p2==SQLITE_CHECKPOINT_RESTART
+  );
+  rc = sqlite3Checkpoint(db, pOp->p1, pOp->p2, &u.ch.aRes[1], &u.ch.aRes[2]);
+  if( rc==SQLITE_BUSY ){
+    rc = SQLITE_OK;
+    u.ch.aRes[0] = 1;
+  }
+  for(u.ch.i=0, u.ch.pMem = &aMem[pOp->p3]; u.ch.i<3; u.ch.i++, u.ch.pMem++){
+    sqlite3VdbeMemSetInt64(u.ch.pMem, (i64)u.ch.aRes[u.ch.i]);
+  }
+  break;
+};  
+#endif
+
+#ifndef SQLITE_OMIT_PRAGMA
+/* Opcode: JournalMode P1 P2 P3 * P5
+**
+** Change the journal mode of database P1 to P3. P3 must be one of the
+** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
+** modes (delete, truncate, persist, off and memory), this is a simple
+** operation. No IO is required.
+**
+** If changing into or out of WAL mode the procedure is more complicated.
+**
+** Write a string containing the final journal-mode to register P2.
+*/
+case OP_JournalMode: {    /* out2-prerelease */
+#if 0  /* local variables moved into u.ci */
+  Btree *pBt;                     /* Btree to change journal mode of */
+  Pager *pPager;                  /* Pager associated with pBt */
+  int eNew;                       /* New journal mode */
+  int eOld;                       /* The old journal mode */
+  const char *zFilename;          /* Name of database file for pPager */
+#endif /* local variables moved into u.ci */
+
+  u.ci.eNew = pOp->p3;
+  assert( u.ci.eNew==PAGER_JOURNALMODE_DELETE
+       || u.ci.eNew==PAGER_JOURNALMODE_TRUNCATE
+       || u.ci.eNew==PAGER_JOURNALMODE_PERSIST
+       || u.ci.eNew==PAGER_JOURNALMODE_OFF
+       || u.ci.eNew==PAGER_JOURNALMODE_MEMORY
+       || u.ci.eNew==PAGER_JOURNALMODE_WAL
+       || u.ci.eNew==PAGER_JOURNALMODE_QUERY
+  );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+
+  u.ci.pBt = db->aDb[pOp->p1].pBt;
+  u.ci.pPager = sqlite3BtreePager(u.ci.pBt);
+  u.ci.eOld = sqlite3PagerGetJournalMode(u.ci.pPager);
+  if( u.ci.eNew==PAGER_JOURNALMODE_QUERY ) u.ci.eNew = u.ci.eOld;
+  if( !sqlite3PagerOkToChangeJournalMode(u.ci.pPager) ) u.ci.eNew = u.ci.eOld;
+
+#ifndef SQLITE_OMIT_WAL
+  u.ci.zFilename = sqlite3PagerFilename(u.ci.pPager, 1);
+
+  /* Do not allow a transition to journal_mode=WAL for a database
+  ** in temporary storage or if the VFS does not support shared memory
+  */
+  if( u.ci.eNew==PAGER_JOURNALMODE_WAL
+   && (sqlite3Strlen30(u.ci.zFilename)==0           /* Temp file */
+       || !sqlite3PagerWalSupported(u.ci.pPager))   /* No shared-memory support */
+  ){
+    u.ci.eNew = u.ci.eOld;
+  }
+
+  if( (u.ci.eNew!=u.ci.eOld)
+   && (u.ci.eOld==PAGER_JOURNALMODE_WAL || u.ci.eNew==PAGER_JOURNALMODE_WAL)
+  ){
+    if( !db->autoCommit || db->activeVdbeCnt>1 ){
+      rc = SQLITE_ERROR;
+      sqlite3SetString(&p->zErrMsg, db,
+          "cannot change %s wal mode from within a transaction",
+          (u.ci.eNew==PAGER_JOURNALMODE_WAL ? "into" : "out of")
+      );
+      break;
+    }else{
+
+      if( u.ci.eOld==PAGER_JOURNALMODE_WAL ){
+        /* If leaving WAL mode, close the log file. If successful, the call
+        ** to PagerCloseWal() checkpoints and deletes the write-ahead-log
+        ** file. An EXCLUSIVE lock may still be held on the database file
+        ** after a successful return.
+        */
+        rc = sqlite3PagerCloseWal(u.ci.pPager);
+        if( rc==SQLITE_OK ){
+          sqlite3PagerSetJournalMode(u.ci.pPager, u.ci.eNew);
+        }
+      }else if( u.ci.eOld==PAGER_JOURNALMODE_MEMORY ){
+        /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
+        ** as an intermediate */
+        sqlite3PagerSetJournalMode(u.ci.pPager, PAGER_JOURNALMODE_OFF);
+      }
+
+      /* Open a transaction on the database file. Regardless of the journal
+      ** mode, this transaction always uses a rollback journal.
+      */
+      assert( sqlite3BtreeIsInTrans(u.ci.pBt)==0 );
+      if( rc==SQLITE_OK ){
+        rc = sqlite3BtreeSetVersion(u.ci.pBt, (u.ci.eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));
+      }
+    }
+  }
+#endif /* ifndef SQLITE_OMIT_WAL */
+
+  if( rc ){
+    u.ci.eNew = u.ci.eOld;
+  }
+  u.ci.eNew = sqlite3PagerSetJournalMode(u.ci.pPager, u.ci.eNew);
+
+  pOut = &aMem[pOp->p2];
+  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
+  pOut->z = (char *)sqlite3JournalModename(u.ci.eNew);
+  pOut->n = sqlite3Strlen30(pOut->z);
+  pOut->enc = SQLITE_UTF8;
+  sqlite3VdbeChangeEncoding(pOut, encoding);
+  break;
+};
+#endif /* SQLITE_OMIT_PRAGMA */
 
 #if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
 /* Opcode: Vacuum * * * * *
@@ -53481,9 +69164,7 @@ case OP_AggFinal: {
 ** a transaction.
 */
 case OP_Vacuum: {
-  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse; 
   rc = sqlite3RunVacuum(&p->zErrMsg, db);
-  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
   break;
 }
 #endif
@@ -53496,12 +69177,14 @@ case OP_Vacuum: {
 ** P2. Otherwise, fall through to the next instruction.
 */
 case OP_IncrVacuum: {        /* jump */
+#if 0  /* local variables moved into u.cj */
   Btree *pBt;
+#endif /* local variables moved into u.cj */
 
   assert( pOp->p1>=0 && pOp->p1<db->nDb );
-  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
-  pBt = db->aDb[pOp->p1].pBt;
-  rc = sqlite3BtreeIncrVacuum(pBt);
+  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
+  u.cj.pBt = db->aDb[pOp->p1].pBt;
+  rc = sqlite3BtreeIncrVacuum(u.cj.pBt);
   if( rc==SQLITE_DONE ){
     pc = pOp->p2 - 1;
     rc = SQLITE_OK;
@@ -53534,7 +69217,7 @@ case OP_Expire: {
 ** Obtain a lock on a particular table. This instruction is only used when
 ** the shared-cache feature is enabled. 
 **
-** If P1 is  the index of the database in sqlite3.aDb[] of the database
+** P1 is the index of the database in sqlite3.aDb[] of the database
 ** on which the lock is acquired.  A readlock is obtained if P3==0 or
 ** a write lock if P3==1.
 **
@@ -53544,15 +69227,17 @@ case OP_Expire: {
 ** used to generate an error message if the lock cannot be obtained.
 */
 case OP_TableLock: {
-  int p1 = pOp->p1; 
   u8 isWriteLock = (u8)pOp->p3;
-  assert( p1>=0 && p1<db->nDb );
-  assert( (p->btreeMask & (1<<p1))!=0 );
-  assert( isWriteLock==0 || isWriteLock==1 );
-  rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
-  if( rc==SQLITE_LOCKED ){
-    const char *z = pOp->p4.z;
-    sqlite3SetString(&p->zErrMsg, db, "database table is locked: %s", z);
+  if( isWriteLock || 0==(db->flags&SQLITE_ReadUncommitted) ){
+    int p1 = pOp->p1; 
+    assert( p1>=0 && p1<db->nDb );
+    assert( (p->btreeMask & (((yDbMask)1)<<p1))!=0 );
+    assert( isWriteLock==0 || isWriteLock==1 );
+    rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
+    if( (rc&0xFF)==SQLITE_LOCKED ){
+      const char *z = pOp->p4.z;
+      sqlite3SetString(&p->zErrMsg, db, "database table is locked: %s", z);
+    }
   }
   break;
 }
@@ -53565,17 +69250,16 @@ case OP_TableLock: {
 ** xBegin method for that table.
 **
 ** Also, whether or not P4 is set, check that this is not being called from
-** within a callback to a virtual table xSync() method. If it is, set the
-** error code to SQLITE_LOCKED.
+** within a callback to a virtual table xSync() method. If it is, the error
+** code will be set to SQLITE_LOCKED.
 */
 case OP_VBegin: {
-  sqlite3_vtab *pVtab = pOp->p4.pVtab;
-  rc = sqlite3VtabBegin(db, pVtab);
-  if( pVtab ){
-    sqlite3DbFree(db, p->zErrMsg);
-    p->zErrMsg = pVtab->zErrMsg;
-    pVtab->zErrMsg = 0;
-  }
+#if 0  /* local variables moved into u.ck */
+  VTable *pVTab;
+#endif /* local variables moved into u.ck */
+  u.ck.pVTab = pOp->p4.pVtab;
+  rc = sqlite3VtabBegin(db, u.ck.pVTab);
+  if( u.ck.pVTab ) importVtabErrMsg(p, u.ck.pVTab->pVtab);
   break;
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -53614,31 +69298,32 @@ case OP_VDestroy: {
 ** table and stores that cursor in P1.
 */
 case OP_VOpen: {
-  VdbeCursor *pCur = 0;
-  sqlite3_vtab_cursor *pVtabCursor = 0;
+#if 0  /* local variables moved into u.cl */
+  VdbeCursor *pCur;
+  sqlite3_vtab_cursor *pVtabCursor;
+  sqlite3_vtab *pVtab;
+  sqlite3_module *pModule;
+#endif /* local variables moved into u.cl */
 
-  sqlite3_vtab *pVtab = pOp->p4.pVtab;
-  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
-
-  assert(pVtab && pModule);
-  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  rc = pModule->xOpen(pVtab, &pVtabCursor);
-  sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = pVtab->zErrMsg;
-  pVtab->zErrMsg = 0;
-  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+  u.cl.pCur = 0;
+  u.cl.pVtabCursor = 0;
+  u.cl.pVtab = pOp->p4.pVtab->pVtab;
+  u.cl.pModule = (sqlite3_module *)u.cl.pVtab->pModule;
+  assert(u.cl.pVtab && u.cl.pModule);
+  rc = u.cl.pModule->xOpen(u.cl.pVtab, &u.cl.pVtabCursor);
+  importVtabErrMsg(p, u.cl.pVtab);
   if( SQLITE_OK==rc ){
     /* Initialize sqlite3_vtab_cursor base class */
-    pVtabCursor->pVtab = pVtab;
+    u.cl.pVtabCursor->pVtab = u.cl.pVtab;
 
     /* Initialise vdbe cursor object */
-    pCur = allocateCursor(p, pOp->p1, &pOp[-1], -1, 0);
-    if( pCur ){
-      pCur->pVtabCursor = pVtabCursor;
-      pCur->pModule = pVtabCursor->pVtab->pModule;
+    u.cl.pCur = allocateCursor(p, pOp->p1, 0, -1, 0);
+    if( u.cl.pCur ){
+      u.cl.pCur->pVtabCursor = u.cl.pVtabCursor;
+      u.cl.pCur->pModule = u.cl.pVtabCursor->pVtab->pModule;
     }else{
       db->mallocFailed = 1;
-      pModule->xClose(pVtabCursor);
+      u.cl.pModule->xClose(u.cl.pVtabCursor);
     }
   }
   break;
@@ -53665,92 +69350,62 @@ case OP_VOpen: {
 ** A jump is made to P2 if the result set after filtering would be empty.
 */
 case OP_VFilter: {   /* jump */
+#if 0  /* local variables moved into u.cm */
   int nArg;
   int iQuery;
   const sqlite3_module *pModule;
-  Mem *pQuery = &p->aMem[pOp->p3];
-  Mem *pArgc = &pQuery[1];
+  Mem *pQuery;
+  Mem *pArgc;
   sqlite3_vtab_cursor *pVtabCursor;
   sqlite3_vtab *pVtab;
+  VdbeCursor *pCur;
+  int res;
+  int i;
+  Mem **apArg;
+#endif /* local variables moved into u.cm */
 
-  VdbeCursor *pCur = p->apCsr[pOp->p1];
-
-  REGISTER_TRACE(pOp->p3, pQuery);
-  assert( pCur->pVtabCursor );
-  pVtabCursor = pCur->pVtabCursor;
-  pVtab = pVtabCursor->pVtab;
-  pModule = pVtab->pModule;
+  u.cm.pQuery = &aMem[pOp->p3];
+  u.cm.pArgc = &u.cm.pQuery[1];
+  u.cm.pCur = p->apCsr[pOp->p1];
+  assert( memIsValid(u.cm.pQuery) );
+  REGISTER_TRACE(pOp->p3, u.cm.pQuery);
+  assert( u.cm.pCur->pVtabCursor );
+  u.cm.pVtabCursor = u.cm.pCur->pVtabCursor;
+  u.cm.pVtab = u.cm.pVtabCursor->pVtab;
+  u.cm.pModule = u.cm.pVtab->pModule;
 
   /* Grab the index number and argc parameters */
-  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
-  nArg = (int)pArgc->u.i;
-  iQuery = (int)pQuery->u.i;
+  assert( (u.cm.pQuery->flags&MEM_Int)!=0 && u.cm.pArgc->flags==MEM_Int );
+  u.cm.nArg = (int)u.cm.pArgc->u.i;
+  u.cm.iQuery = (int)u.cm.pQuery->u.i;
 
   /* Invoke the xFilter method */
   {
-    int res = 0;
-    int i;
-    Mem **apArg = p->apArg;
-    for(i = 0; i<nArg; i++){
-      apArg[i] = &pArgc[i+1];
-      storeTypeInfo(apArg[i], 0);
+    u.cm.res = 0;
+    u.cm.apArg = p->apArg;
+    for(u.cm.i = 0; u.cm.i<u.cm.nArg; u.cm.i++){
+      u.cm.apArg[u.cm.i] = &u.cm.pArgc[u.cm.i+1];
+      sqlite3VdbeMemStoreType(u.cm.apArg[u.cm.i]);
     }
 
-    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-    sqlite3VtabLock(pVtab);
     p->inVtabMethod = 1;
-    rc = pModule->xFilter(pVtabCursor, iQuery, pOp->p4.z, nArg, apArg);
+    rc = u.cm.pModule->xFilter(u.cm.pVtabCursor, u.cm.iQuery, pOp->p4.z, u.cm.nArg, u.cm.apArg);
     p->inVtabMethod = 0;
-    sqlite3DbFree(db, p->zErrMsg);
-    p->zErrMsg = pVtab->zErrMsg;
-    pVtab->zErrMsg = 0;
-    sqlite3VtabUnlock(db, pVtab);
+    importVtabErrMsg(p, u.cm.pVtab);
     if( rc==SQLITE_OK ){
-      res = pModule->xEof(pVtabCursor);
+      u.cm.res = u.cm.pModule->xEof(u.cm.pVtabCursor);
     }
-    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
 
-    if( res ){
+    if( u.cm.res ){
       pc = pOp->p2 - 1;
     }
   }
-  pCur->nullRow = 0;
+  u.cm.pCur->nullRow = 0;
 
   break;
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-/* Opcode: VRowid P1 P2 * * *
-**
-** Store into register P2  the rowid of
-** the virtual-table that the P1 cursor is pointing to.
-*/
-case OP_VRowid: {             /* out2-prerelease */
-  sqlite3_vtab *pVtab;
-  const sqlite3_module *pModule;
-  sqlite_int64 iRow;
-  VdbeCursor *pCur = p->apCsr[pOp->p1];
-
-  assert( pCur->pVtabCursor );
-  if( pCur->nullRow ){
-    break;
-  }
-  pVtab = pCur->pVtabCursor->pVtab;
-  pModule = pVtab->pModule;
-  assert( pModule->xRowid );
-  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  rc = pModule->xRowid(pCur->pVtabCursor, &iRow);
-  sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = pVtab->zErrMsg;
-  pVtab->zErrMsg = 0;
-  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
-  MemSetTypeFlag(pOut, MEM_Int);
-  pOut->u.i = iRow;
-  break;
-}
-#endif /* SQLITE_OMIT_VIRTUALTABLE */
-
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /* Opcode: VColumn P1 P2 P3 * *
 **
@@ -53759,51 +69414,51 @@ case OP_VRowid: {             /* out2-prerelease */
 ** P1 cursor is pointing to into register P3.
 */
 case OP_VColumn: {
+#if 0  /* local variables moved into u.cn */
   sqlite3_vtab *pVtab;
   const sqlite3_module *pModule;
   Mem *pDest;
   sqlite3_context sContext;
+#endif /* local variables moved into u.cn */
 
   VdbeCursor *pCur = p->apCsr[pOp->p1];
   assert( pCur->pVtabCursor );
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  pDest = &p->aMem[pOp->p3];
+  u.cn.pDest = &aMem[pOp->p3];
+  memAboutToChange(p, u.cn.pDest);
   if( pCur->nullRow ){
-    sqlite3VdbeMemSetNull(pDest);
+    sqlite3VdbeMemSetNull(u.cn.pDest);
     break;
   }
-  pVtab = pCur->pVtabCursor->pVtab;
-  pModule = pVtab->pModule;
-  assert( pModule->xColumn );
-  memset(&sContext, 0, sizeof(sContext));
+  u.cn.pVtab = pCur->pVtabCursor->pVtab;
+  u.cn.pModule = u.cn.pVtab->pModule;
+  assert( u.cn.pModule->xColumn );
+  memset(&u.cn.sContext, 0, sizeof(u.cn.sContext));
 
   /* The output cell may already have a buffer allocated. Move
-  ** the current contents to sContext.s so in case the user-function 
-  ** can use the already allocated buffer instead of allocating a 
+  ** the current contents to u.cn.sContext.s so in case the user-function
+  ** can use the already allocated buffer instead of allocating a
   ** new one.
   */
-  sqlite3VdbeMemMove(&sContext.s, pDest);
-  MemSetTypeFlag(&sContext.s, MEM_Null);
+  sqlite3VdbeMemMove(&u.cn.sContext.s, u.cn.pDest);
+  MemSetTypeFlag(&u.cn.sContext.s, MEM_Null);
 
-  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  rc = pModule->xColumn(pCur->pVtabCursor, &sContext, pOp->p2);
-  sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = pVtab->zErrMsg;
-  pVtab->zErrMsg = 0;
+  rc = u.cn.pModule->xColumn(pCur->pVtabCursor, &u.cn.sContext, pOp->p2);
+  importVtabErrMsg(p, u.cn.pVtab);
+  if( u.cn.sContext.isError ){
+    rc = u.cn.sContext.isError;
+  }
 
   /* Copy the result of the function to the P3 register. We
-  ** do this regardless of whether or not an error occured to ensure any
-  ** dynamic allocation in sContext.s (a Mem struct) is  released.
+  ** do this regardless of whether or not an error occurred to ensure any
+  ** dynamic allocation in u.cn.sContext.s (a Mem struct) is  released.
   */
-  sqlite3VdbeChangeEncoding(&sContext.s, encoding);
-  REGISTER_TRACE(pOp->p3, pDest);
-  sqlite3VdbeMemMove(pDest, &sContext.s);
-  UPDATE_MAX_BLOBSIZE(pDest);
+  sqlite3VdbeChangeEncoding(&u.cn.sContext.s, encoding);
+  sqlite3VdbeMemMove(u.cn.pDest, &u.cn.sContext.s);
+  REGISTER_TRACE(pOp->p3, u.cn.pDest);
+  UPDATE_MAX_BLOBSIZE(u.cn.pDest);
 
-  if( sqlite3SafetyOn(db) ){
-    goto abort_due_to_misuse;
-  }
-  if( sqlite3VdbeMemTooBig(pDest) ){
+  if( sqlite3VdbeMemTooBig(u.cn.pDest) ){
     goto too_big;
   }
   break;
@@ -53818,40 +69473,38 @@ case OP_VColumn: {
 ** the end of its result set, then fall through to the next instruction.
 */
 case OP_VNext: {   /* jump */
+#if 0  /* local variables moved into u.co */
   sqlite3_vtab *pVtab;
   const sqlite3_module *pModule;
-  int res = 0;
+  int res;
+  VdbeCursor *pCur;
+#endif /* local variables moved into u.co */
 
-  VdbeCursor *pCur = p->apCsr[pOp->p1];
-  assert( pCur->pVtabCursor );
-  if( pCur->nullRow ){
+  u.co.res = 0;
+  u.co.pCur = p->apCsr[pOp->p1];
+  assert( u.co.pCur->pVtabCursor );
+  if( u.co.pCur->nullRow ){
     break;
   }
-  pVtab = pCur->pVtabCursor->pVtab;
-  pModule = pVtab->pModule;
-  assert( pModule->xNext );
+  u.co.pVtab = u.co.pCur->pVtabCursor->pVtab;
+  u.co.pModule = u.co.pVtab->pModule;
+  assert( u.co.pModule->xNext );
 
   /* Invoke the xNext() method of the module. There is no way for the
   ** underlying implementation to return an error if one occurs during
-  ** xNext(). Instead, if an error occurs, true is returned (indicating that 
+  ** xNext(). Instead, if an error occurs, true is returned (indicating that
   ** data is available) and the error code returned when xColumn or
   ** some other method is next invoked on the save virtual table cursor.
   */
-  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  sqlite3VtabLock(pVtab);
   p->inVtabMethod = 1;
-  rc = pModule->xNext(pCur->pVtabCursor);
+  rc = u.co.pModule->xNext(u.co.pCur->pVtabCursor);
   p->inVtabMethod = 0;
-  sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = pVtab->zErrMsg;
-  pVtab->zErrMsg = 0;
-  sqlite3VtabUnlock(db, pVtab);
+  importVtabErrMsg(p, u.co.pVtab);
   if( rc==SQLITE_OK ){
-    res = pModule->xEof(pCur->pVtabCursor);
+    u.co.res = u.co.pModule->xEof(u.co.pCur->pVtabCursor);
   }
-  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
 
-  if( !res ){
+  if( !u.co.res ){
     /* If there is data, jump to P2 */
     pc = pOp->p2 - 1;
   }
@@ -53867,22 +69520,26 @@ case OP_VNext: {   /* jump */
 ** in register P1 is passed as the zName argument to the xRename method.
 */
 case OP_VRename: {
-  sqlite3_vtab *pVtab = pOp->p4.pVtab;
-  Mem *pName = &p->aMem[pOp->p1];
-  assert( pVtab->pModule->xRename );
-  REGISTER_TRACE(pOp->p1, pName);
-
-  Stringify(pName, encoding);
-
-  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  sqlite3VtabLock(pVtab);
-  rc = pVtab->pModule->xRename(pVtab, pName->z);
-  sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = pVtab->zErrMsg;
-  pVtab->zErrMsg = 0;
-  sqlite3VtabUnlock(db, pVtab);
-  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+#if 0  /* local variables moved into u.cp */
+  sqlite3_vtab *pVtab;
+  Mem *pName;
+#endif /* local variables moved into u.cp */
 
+  u.cp.pVtab = pOp->p4.pVtab->pVtab;
+  u.cp.pName = &aMem[pOp->p1];
+  assert( u.cp.pVtab->pModule->xRename );
+  assert( memIsValid(u.cp.pName) );
+  REGISTER_TRACE(pOp->p1, u.cp.pName);
+  assert( u.cp.pName->flags & MEM_Str );
+  testcase( u.cp.pName->enc==SQLITE_UTF8 );
+  testcase( u.cp.pName->enc==SQLITE_UTF16BE );
+  testcase( u.cp.pName->enc==SQLITE_UTF16LE );
+  rc = sqlite3VdbeChangeEncoding(u.cp.pName, SQLITE_UTF8);
+  if( rc==SQLITE_OK ){
+    rc = u.cp.pVtab->pModule->xRename(u.cp.pVtab, u.cp.pName->z);
+    importVtabErrMsg(p, u.cp.pVtab);
+    p->expired = 0;
+  }
   break;
 }
 #endif
@@ -53912,36 +69569,51 @@ case OP_VRename: {
 ** is set to the value of the rowid for the row just inserted.
 */
 case OP_VUpdate: {
-  sqlite3_vtab *pVtab = pOp->p4.pVtab;
-  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
-  int nArg = pOp->p2;
+#if 0  /* local variables moved into u.cq */
+  sqlite3_vtab *pVtab;
+  sqlite3_module *pModule;
+  int nArg;
+  int i;
+  sqlite_int64 rowid;
+  Mem **apArg;
+  Mem *pX;
+#endif /* local variables moved into u.cq */
+
+  assert( pOp->p2==1        || pOp->p5==OE_Fail   || pOp->p5==OE_Rollback
+       || pOp->p5==OE_Abort || pOp->p5==OE_Ignore || pOp->p5==OE_Replace
+  );
+  u.cq.pVtab = pOp->p4.pVtab->pVtab;
+  u.cq.pModule = (sqlite3_module *)u.cq.pVtab->pModule;
+  u.cq.nArg = pOp->p2;
   assert( pOp->p4type==P4_VTAB );
-  if( pModule->xUpdate==0 ){
-    sqlite3SetString(&p->zErrMsg, db, "read-only table");
-    rc = SQLITE_ERROR;
-  }else{
-    int i;
-    sqlite_int64 rowid;
-    Mem **apArg = p->apArg;
-    Mem *pX = &p->aMem[pOp->p3];
-    for(i=0; i<nArg; i++){
-      storeTypeInfo(pX, 0);
-      apArg[i] = pX;
-      pX++;
+  if( ALWAYS(u.cq.pModule->xUpdate) ){
+    u8 vtabOnConflict = db->vtabOnConflict;
+    u.cq.apArg = p->apArg;
+    u.cq.pX = &aMem[pOp->p3];
+    for(u.cq.i=0; u.cq.i<u.cq.nArg; u.cq.i++){
+      assert( memIsValid(u.cq.pX) );
+      memAboutToChange(p, u.cq.pX);
+      sqlite3VdbeMemStoreType(u.cq.pX);
+      u.cq.apArg[u.cq.i] = u.cq.pX;
+      u.cq.pX++;
     }
-    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-    sqlite3VtabLock(pVtab);
-    rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
-    sqlite3DbFree(db, p->zErrMsg);
-    p->zErrMsg = pVtab->zErrMsg;
-    pVtab->zErrMsg = 0;
-    sqlite3VtabUnlock(db, pVtab);
-    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
-    if( pOp->p1 && rc==SQLITE_OK ){
-      assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
-      db->lastRowid = rowid;
+    db->vtabOnConflict = pOp->p5;
+    rc = u.cq.pModule->xUpdate(u.cq.pVtab, u.cq.nArg, u.cq.apArg, &u.cq.rowid);
+    db->vtabOnConflict = vtabOnConflict;
+    importVtabErrMsg(p, u.cq.pVtab);
+    if( rc==SQLITE_OK && pOp->p1 ){
+      assert( u.cq.nArg>1 && u.cq.apArg[0] && (u.cq.apArg[0]->flags&MEM_Null) );
+      db->lastRowid = lastRowid = u.cq.rowid;
+    }
+    if( rc==SQLITE_CONSTRAINT && pOp->p4.pVtab->bConstraint ){
+      if( pOp->p5==OE_Ignore ){
+        rc = SQLITE_OK;
+      }else{
+        p->errorAction = ((pOp->p5==OE_Replace) ? OE_Abort : pOp->p5);
+      }
+    }else{
+      p->nChange++;
     }
-    p->nChange++;
   }
   break;
 }
@@ -53953,19 +69625,37 @@ case OP_VUpdate: {
 ** Write the current number of pages in database P1 to memory cell P2.
 */
 case OP_Pagecount: {            /* out2-prerelease */
-  int p1 = pOp->p1; 
-  int nPage;
-  Pager *pPager = sqlite3BtreePager(db->aDb[p1].pBt);
-
-  rc = sqlite3PagerPagecount(pPager, &nPage);
-  if( rc==SQLITE_OK ){
-    pOut->flags = MEM_Int;
-    pOut->u.i = nPage;
-  }
+  pOut->u.i = sqlite3BtreeLastPage(db->aDb[pOp->p1].pBt);
   break;
 }
 #endif
 
+
+#ifndef  SQLITE_OMIT_PAGER_PRAGMAS
+/* Opcode: MaxPgcnt P1 P2 P3 * *
+**
+** Try to set the maximum page count for database P1 to the value in P3.
+** Do not let the maximum page count fall below the current page count and
+** do not change the maximum page count value if P3==0.
+**
+** Store the maximum page count after the change in register P2.
+*/
+case OP_MaxPgcnt: {            /* out2-prerelease */
+  unsigned int newMax;
+  Btree *pBt;
+
+  pBt = db->aDb[pOp->p1].pBt;
+  newMax = 0;
+  if( pOp->p3 ){
+    newMax = sqlite3BtreeLastPage(pBt);
+    if( newMax < (unsigned)pOp->p3 ) newMax = (unsigned)pOp->p3;
+  }
+  pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
+  break;
+}
+#endif
+
+
 #ifndef SQLITE_OMIT_TRACE
 /* Opcode: Trace * * * P4 *
 **
@@ -53973,16 +69663,23 @@ case OP_Pagecount: {            /* out2-prerelease */
 ** the UTF-8 string contained in P4 is emitted on the trace callback.
 */
 case OP_Trace: {
-  if( pOp->p4.z ){
-    if( db->xTrace ){
-      db->xTrace(db->pTraceArg, pOp->p4.z);
-    }
-#ifdef SQLITE_DEBUG
-    if( (db->flags & SQLITE_SqlTrace)!=0 ){
-      sqlite3DebugPrintf("SQL-trace: %s\n", pOp->p4.z);
-    }
-#endif /* SQLITE_DEBUG */
+#if 0  /* local variables moved into u.cr */
+  char *zTrace;
+  char *z;
+#endif /* local variables moved into u.cr */
+
+  if( db->xTrace && (u.cr.zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0 ){
+    u.cr.z = sqlite3VdbeExpandSql(p, u.cr.zTrace);
+    db->xTrace(db->pTraceArg, u.cr.z);
+    sqlite3DbFree(db, u.cr.z);
   }
+#ifdef SQLITE_DEBUG
+  if( (db->flags & SQLITE_SqlTrace)!=0
+   && (u.cr.zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
+  ){
+    sqlite3DebugPrintf("SQL-trace: %s\n", u.cr.zTrace);
+  }
+#endif /* SQLITE_DEBUG */
   break;
 }
 #endif
@@ -54000,6 +69697,7 @@ case OP_Trace: {
 ** the same as a no-op.  This opcodesnever appears in a real VM program.
 */
 default: {          /* This is really OP_Noop and OP_Explain */
+  assert( pOp->opcode==OP_Noop || pOp->opcode==OP_Explain );
   break;
 }
 
@@ -54018,7 +69716,7 @@ default: {          /* This is really OP_Noop and OP_Explain */
       pOp->cnt++;
 #if 0
         fprintf(stdout, "%10llu ", elapsed);
-        sqlite3VdbePrintOp(stdout, origPc, &p->aOp[origPc]);
+        sqlite3VdbePrintOp(stdout, origPc, &aOp[origPc]);
 #endif
     }
 #endif
@@ -54034,11 +69732,11 @@ default: {          /* This is really OP_Noop and OP_Explain */
 #ifdef SQLITE_DEBUG
     if( p->trace ){
       if( rc!=0 ) fprintf(p->trace,"rc=%d\n",rc);
-      if( opProperty & OPFLG_OUT2_PRERELEASE ){
-        registerTrace(p->trace, pOp->p2, pOut);
+      if( pOp->opflags & (OPFLG_OUT2_PRERELEASE|OPFLG_OUT2) ){
+        registerTrace(p->trace, pOp->p2, &aMem[pOp->p2]);
       }
-      if( opProperty & OPFLG_OUT3 ){
-        registerTrace(p->trace, pOp->p3, pOut);
+      if( pOp->opflags & OPFLG_OUT3 ){
+        registerTrace(p->trace, pOp->p3, &aMem[pOp->p3]);
       }
     }
 #endif  /* SQLITE_DEBUG */
@@ -54051,15 +69749,22 @@ default: {          /* This is really OP_Noop and OP_Explain */
 vdbe_error_halt:
   assert( rc );
   p->rc = rc;
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  sqlite3_log(rc, "statement aborts at %d: [%s] %s", 
+                   pc, p->zSql, p->zErrMsg);
   sqlite3VdbeHalt(p);
   if( rc==SQLITE_IOERR_NOMEM ) db->mallocFailed = 1;
   rc = SQLITE_ERROR;
+  if( resetSchemaOnFault>0 ){
+    sqlite3ResetOneSchema(db, resetSchemaOnFault-1);
+  }
 
   /* This is the only way out of this procedure.  We have to
   ** release the mutexes on btrees that were acquired at the
   ** top. */
 vdbe_return:
-  sqlite3BtreeMutexArrayLeave(&p->aMutex);
+  db->lastRowid = lastRowid;
+  sqlite3VdbeLeave(p);
   return rc;
 
   /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
@@ -54078,12 +69783,6 @@ no_mem:
   rc = SQLITE_NOMEM;
   goto vdbe_error_halt;
 
-  /* Jump to here for an SQLITE_MISUSE error.
-  */
-abort_due_to_misuse:
-  rc = SQLITE_MISUSE;
-  /* Fall thru into abort_due_to_error */
-
   /* Jump to here for any other kind of fatal error.  The "rc" variable
   ** should hold the error number.
   */
@@ -54121,8 +69820,6 @@ abort_due_to_interrupt:
 *************************************************************************
 **
 ** This file contains code used to implement incremental BLOB I/O.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
@@ -54136,11 +69833,82 @@ struct Incrblob {
   int flags;              /* Copy of "flags" passed to sqlite3_blob_open() */
   int nByte;              /* Size of open blob, in bytes */
   int iOffset;            /* Byte offset of blob in cursor data */
+  int iCol;               /* Table column this handle is open on */
   BtCursor *pCsr;         /* Cursor pointing at blob row */
   sqlite3_stmt *pStmt;    /* Statement holding cursor open */
   sqlite3 *db;            /* The associated database */
 };
 
+
+/*
+** This function is used by both blob_open() and blob_reopen(). It seeks
+** the b-tree cursor associated with blob handle p to point to row iRow.
+** If successful, SQLITE_OK is returned and subsequent calls to
+** sqlite3_blob_read() or sqlite3_blob_write() access the specified row.
+**
+** If an error occurs, or if the specified row does not exist or does not
+** contain a value of type TEXT or BLOB in the column nominated when the
+** blob handle was opened, then an error code is returned and *pzErr may
+** be set to point to a buffer containing an error message. It is the
+** responsibility of the caller to free the error message buffer using
+** sqlite3DbFree().
+**
+** If an error does occur, then the b-tree cursor is closed. All subsequent
+** calls to sqlite3_blob_read(), blob_write() or blob_reopen() will 
+** immediately return SQLITE_ABORT.
+*/
+static int blobSeekToRow(Incrblob *p, sqlite3_int64 iRow, char **pzErr){
+  int rc;                         /* Error code */
+  char *zErr = 0;                 /* Error message */
+  Vdbe *v = (Vdbe *)p->pStmt;
+
+  /* Set the value of the SQL statements only variable to integer iRow. 
+  ** This is done directly instead of using sqlite3_bind_int64() to avoid 
+  ** triggering asserts related to mutexes.
+  */
+  assert( v->aVar[0].flags&MEM_Int );
+  v->aVar[0].u.i = iRow;
+
+  rc = sqlite3_step(p->pStmt);
+  if( rc==SQLITE_ROW ){
+    u32 type = v->apCsr[0]->aType[p->iCol];
+    if( type<12 ){
+      zErr = sqlite3MPrintf(p->db, "cannot open value of type %s",
+          type==0?"null": type==7?"real": "integer"
+      );
+      rc = SQLITE_ERROR;
+      sqlite3_finalize(p->pStmt);
+      p->pStmt = 0;
+    }else{
+      p->iOffset = v->apCsr[0]->aOffset[p->iCol];
+      p->nByte = sqlite3VdbeSerialTypeLen(type);
+      p->pCsr =  v->apCsr[0]->pCursor;
+      sqlite3BtreeEnterCursor(p->pCsr);
+      sqlite3BtreeCacheOverflow(p->pCsr);
+      sqlite3BtreeLeaveCursor(p->pCsr);
+    }
+  }
+
+  if( rc==SQLITE_ROW ){
+    rc = SQLITE_OK;
+  }else if( p->pStmt ){
+    rc = sqlite3_finalize(p->pStmt);
+    p->pStmt = 0;
+    if( rc==SQLITE_OK ){
+      zErr = sqlite3MPrintf(p->db, "no such rowid: %lld", iRow);
+      rc = SQLITE_ERROR;
+    }else{
+      zErr = sqlite3MPrintf(p->db, "%s", sqlite3_errmsg(p->db));
+    }
+  }
+
+  assert( rc!=SQLITE_OK || zErr==0 );
+  assert( rc!=SQLITE_ROW && rc!=SQLITE_DONE );
+
+  *pzErr = zErr;
+  return rc;
+}
+
 /*
 ** Open a blob handle.
 */
@@ -54174,194 +69942,196 @@ SQLITE_API int sqlite3_blob_open(
   static const VdbeOpList openBlob[] = {
     {OP_Transaction, 0, 0, 0},     /* 0: Start a transaction */
     {OP_VerifyCookie, 0, 0, 0},    /* 1: Check the schema cookie */
+    {OP_TableLock, 0, 0, 0},       /* 2: Acquire a read or write lock */
 
-    /* One of the following two instructions is replaced by an
-    ** OP_Noop before exection.
-    */
-    {OP_SetNumColumns, 0, 0, 0},   /* 2: Num cols for cursor */
+    /* One of the following two instructions is replaced by an OP_Noop. */
     {OP_OpenRead, 0, 0, 0},        /* 3: Open cursor 0 for reading */
-    {OP_SetNumColumns, 0, 0, 0},   /* 4: Num cols for cursor */
-    {OP_OpenWrite, 0, 0, 0},       /* 5: Open cursor 0 for read/write */
+    {OP_OpenWrite, 0, 0, 0},       /* 4: Open cursor 0 for read/write */
 
-    {OP_Variable, 1, 1, 0},        /* 6: Push the rowid to the stack */
-    {OP_NotExists, 0, 10, 1},      /* 7: Seek the cursor */
-    {OP_Column, 0, 0, 1},          /* 8  */
-    {OP_ResultRow, 1, 0, 0},       /* 9  */
-    {OP_Close, 0, 0, 0},           /* 10  */
+    {OP_Variable, 1, 1, 1},        /* 5: Push the rowid to the stack */
+    {OP_NotExists, 0, 10, 1},      /* 6: Seek the cursor */
+    {OP_Column, 0, 0, 1},          /* 7  */
+    {OP_ResultRow, 1, 0, 0},       /* 8  */
+    {OP_Goto, 0, 5, 0},            /* 9  */
+    {OP_Close, 0, 0, 0},           /* 10 */
     {OP_Halt, 0, 0, 0},            /* 11 */
   };
 
-  Vdbe *v = 0;
   int rc = SQLITE_OK;
-  char zErr[128];
+  char *zErr = 0;
+  Table *pTab;
+  Parse *pParse = 0;
+  Incrblob *pBlob = 0;
+
+  flags = !!flags;                /* flags = (flags ? 1 : 0); */
+  *ppBlob = 0;
 
-  zErr[0] = 0;
   sqlite3_mutex_enter(db->mutex);
+
+  pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
+  if( !pBlob ) goto blob_open_out;
+  pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
+  if( !pParse ) goto blob_open_out;
+
   do {
-    Parse sParse;
-    Table *pTab;
-
-    memset(&sParse, 0, sizeof(Parse));
-    sParse.db = db;
-
-    if( sqlite3SafetyOn(db) ){
-      sqlite3_mutex_leave(db->mutex);
-      return SQLITE_MISUSE;
-    }
+    memset(pParse, 0, sizeof(Parse));
+    pParse->db = db;
+    sqlite3DbFree(db, zErr);
+    zErr = 0;
 
     sqlite3BtreeEnterAll(db);
-    pTab = sqlite3LocateTable(&sParse, 0, zTable, zDb);
+    pTab = sqlite3LocateTable(pParse, 0, zTable, zDb);
     if( pTab && IsVirtual(pTab) ){
       pTab = 0;
-      sqlite3ErrorMsg(&sParse, "cannot open virtual table: %s", zTable);
+      sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable);
     }
 #ifndef SQLITE_OMIT_VIEW
     if( pTab && pTab->pSelect ){
       pTab = 0;
-      sqlite3ErrorMsg(&sParse, "cannot open view: %s", zTable);
+      sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable);
     }
 #endif
     if( !pTab ){
-      if( sParse.zErrMsg ){
-        sqlite3_snprintf(sizeof(zErr), zErr, "%s", sParse.zErrMsg);
+      if( pParse->zErrMsg ){
+        sqlite3DbFree(db, zErr);
+        zErr = pParse->zErrMsg;
+        pParse->zErrMsg = 0;
       }
-      sqlite3DbFree(db, sParse.zErrMsg);
       rc = SQLITE_ERROR;
-      (void)sqlite3SafetyOff(db);
       sqlite3BtreeLeaveAll(db);
       goto blob_open_out;
     }
 
     /* Now search pTab for the exact column. */
-    for(iCol=0; iCol < pTab->nCol; iCol++) {
+    for(iCol=0; iCol<pTab->nCol; iCol++) {
       if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
         break;
       }
     }
     if( iCol==pTab->nCol ){
-      sqlite3_snprintf(sizeof(zErr), zErr, "no such column: \"%s\"", zColumn);
+      sqlite3DbFree(db, zErr);
+      zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
       rc = SQLITE_ERROR;
-      (void)sqlite3SafetyOff(db);
       sqlite3BtreeLeaveAll(db);
       goto blob_open_out;
     }
 
     /* If the value is being opened for writing, check that the
-    ** column is not indexed. It is against the rules to open an
-    ** indexed column for writing.
-    */
+    ** column is not indexed, and that it is not part of a foreign key. 
+    ** It is against the rules to open a column to which either of these
+    ** descriptions applies for writing.  */
     if( flags ){
+      const char *zFault = 0;
       Index *pIdx;
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+      if( db->flags&SQLITE_ForeignKeys ){
+        /* Check that the column is not part of an FK child key definition. It
+        ** is not necessary to check if it is part of a parent key, as parent
+        ** key columns must be indexed. The check below will pick up this 
+        ** case.  */
+        FKey *pFKey;
+        for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
+          int j;
+          for(j=0; j<pFKey->nCol; j++){
+            if( pFKey->aCol[j].iFrom==iCol ){
+              zFault = "foreign key";
+            }
+          }
+        }
+      }
+#endif
       for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
         int j;
         for(j=0; j<pIdx->nColumn; j++){
           if( pIdx->aiColumn[j]==iCol ){
-            sqlite3_snprintf(sizeof(zErr), zErr,
-                             "cannot open indexed column for writing");
-            rc = SQLITE_ERROR;
-            (void)sqlite3SafetyOff(db);
-            sqlite3BtreeLeaveAll(db);
-            goto blob_open_out;
+            zFault = "indexed";
           }
         }
       }
+      if( zFault ){
+        sqlite3DbFree(db, zErr);
+        zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);
+        rc = SQLITE_ERROR;
+        sqlite3BtreeLeaveAll(db);
+        goto blob_open_out;
+      }
     }
 
-    v = sqlite3VdbeCreate(db);
-    if( v ){
+    pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(db);
+    assert( pBlob->pStmt || db->mallocFailed );
+    if( pBlob->pStmt ){
+      Vdbe *v = (Vdbe *)pBlob->pStmt;
       int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+
       sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
 
+
       /* Configure the OP_Transaction */
       sqlite3VdbeChangeP1(v, 0, iDb);
-      sqlite3VdbeChangeP2(v, 0, (flags ? 1 : 0));
+      sqlite3VdbeChangeP2(v, 0, flags);
 
       /* Configure the OP_VerifyCookie */
       sqlite3VdbeChangeP1(v, 1, iDb);
       sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
+      sqlite3VdbeChangeP3(v, 1, pTab->pSchema->iGeneration);
 
       /* Make sure a mutex is held on the table to be accessed */
       sqlite3VdbeUsesBtree(v, iDb); 
 
-      /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
-      ** parameter of the other to pTab->tnum. 
-      */
-      sqlite3VdbeChangeToNoop(v, (flags ? 3 : 5), 1);
-      sqlite3VdbeChangeP2(v, (flags ? 5 : 3), pTab->tnum);
-      sqlite3VdbeChangeP3(v, (flags ? 5 : 3), iDb);
+      /* Configure the OP_TableLock instruction */
+#ifdef SQLITE_OMIT_SHARED_CACHE
+      sqlite3VdbeChangeToNoop(v, 2);
+#else
+      sqlite3VdbeChangeP1(v, 2, iDb);
+      sqlite3VdbeChangeP2(v, 2, pTab->tnum);
+      sqlite3VdbeChangeP3(v, 2, flags);
+      sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
+#endif
 
-      /* Configure the OP_SetNumColumns. Configure the cursor to
+      /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
+      ** parameter of the other to pTab->tnum.  */
+      sqlite3VdbeChangeToNoop(v, 4 - flags);
+      sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
+      sqlite3VdbeChangeP3(v, 3 + flags, iDb);
+
+      /* Configure the number of columns. Configure the cursor to
       ** think that the table has one more column than it really
       ** does. An OP_Column to retrieve this imaginary column will
       ** always return an SQL NULL. This is useful because it means
       ** we can invoke OP_Column to fill in the vdbe cursors type 
       ** and offset cache without causing any IO.
       */
-      sqlite3VdbeChangeP2(v, flags ? 4 : 2, pTab->nCol+1);
-      sqlite3VdbeChangeP2(v, 8, pTab->nCol);
+      sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
+      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
       if( !db->mallocFailed ){
-        sqlite3VdbeMakeReady(v, 1, 1, 1, 0);
+        pParse->nVar = 1;
+        pParse->nMem = 1;
+        pParse->nTab = 1;
+        sqlite3VdbeMakeReady(v, pParse);
       }
     }
    
-    sqlite3BtreeLeaveAll(db);
-    rc = sqlite3SafetyOff(db);
-    if( rc!=SQLITE_OK || db->mallocFailed ){
-      goto blob_open_out;
-    }
-
-    sqlite3_bind_int64((sqlite3_stmt *)v, 1, iRow);
-    rc = sqlite3_step((sqlite3_stmt *)v);
-    if( rc!=SQLITE_ROW ){
-      nAttempt++;
-      rc = sqlite3_finalize((sqlite3_stmt *)v);
-      sqlite3_snprintf(sizeof(zErr), zErr, sqlite3_errmsg(db));
-      v = 0;
-    }
-  } while( nAttempt<5 && rc==SQLITE_SCHEMA );
-
-  if( rc==SQLITE_ROW ){
-    /* The row-record has been opened successfully. Check that the
-    ** column in question contains text or a blob. If it contains
-    ** text, it is up to the caller to get the encoding right.
-    */
-    Incrblob *pBlob;
-    u32 type = v->apCsr[0]->aType[iCol];
-
-    if( type<12 ){
-      sqlite3_snprintf(sizeof(zErr), zErr, "cannot open value of type %s",
-          type==0?"null": type==7?"real": "integer"
-      );
-      rc = SQLITE_ERROR;
-      goto blob_open_out;
-    }
-    pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
-    if( db->mallocFailed ){
-      sqlite3DbFree(db, pBlob);
-      goto blob_open_out;
-    }
     pBlob->flags = flags;
-    pBlob->pCsr =  v->apCsr[0]->pCursor;
-    sqlite3BtreeEnterCursor(pBlob->pCsr);
-    sqlite3BtreeCacheOverflow(pBlob->pCsr);
-    sqlite3BtreeLeaveCursor(pBlob->pCsr);
-    pBlob->pStmt = (sqlite3_stmt *)v;
-    pBlob->iOffset = v->apCsr[0]->aOffset[iCol];
-    pBlob->nByte = sqlite3VdbeSerialTypeLen(type);
+    pBlob->iCol = iCol;
     pBlob->db = db;
-    *ppBlob = (sqlite3_blob *)pBlob;
-    rc = SQLITE_OK;
-  }else if( rc==SQLITE_OK ){
-    sqlite3_snprintf(sizeof(zErr), zErr, "no such rowid: %lld", iRow);
-    rc = SQLITE_ERROR;
-  }
+    sqlite3BtreeLeaveAll(db);
+    if( db->mallocFailed ){
+      goto blob_open_out;
+    }
+    sqlite3_bind_int64(pBlob->pStmt, 1, iRow);
+    rc = blobSeekToRow(pBlob, iRow, &zErr);
+  } while( (++nAttempt)<5 && rc==SQLITE_SCHEMA );
 
 blob_open_out:
-  zErr[sizeof(zErr)-1] = '\0';
-  if( rc!=SQLITE_OK || db->mallocFailed ){
-    sqlite3_finalize((sqlite3_stmt *)v);
+  if( rc==SQLITE_OK && db->mallocFailed==0 ){
+    *ppBlob = (sqlite3_blob *)pBlob;
+  }else{
+    if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt);
+    sqlite3DbFree(db, pBlob);
   }
-  sqlite3Error(db, rc, (rc==SQLITE_OK?0:zErr));
+  sqlite3Error(db, rc, (zErr ? "%s" : 0), zErr);
+  sqlite3DbFree(db, zErr);
+  sqlite3StackFree(db, pParse);
   rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
@@ -54374,9 +70144,17 @@ blob_open_out:
 SQLITE_API int sqlite3_blob_close(sqlite3_blob *pBlob){
   Incrblob *p = (Incrblob *)pBlob;
   int rc;
+  sqlite3 *db;
 
-  rc = sqlite3_finalize(p->pStmt);
-  sqlite3DbFree(p->db, p);
+  if( p ){
+    db = p->db;
+    sqlite3_mutex_enter(db->mutex);
+    rc = sqlite3_finalize(p->pStmt);
+    sqlite3DbFree(db, p);
+    sqlite3_mutex_leave(db->mutex);
+  }else{
+    rc = SQLITE_OK;
+  }
   return rc;
 }
 
@@ -54393,8 +70171,10 @@ static int blobReadWrite(
   int rc;
   Incrblob *p = (Incrblob *)pBlob;
   Vdbe *v;
-  sqlite3 *db = p->db;  
+  sqlite3 *db;
 
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+  db = p->db;
   sqlite3_mutex_enter(db->mutex);
   v = (Vdbe*)p->pStmt;
 
@@ -54402,7 +70182,7 @@ static int blobReadWrite(
     /* Request is out of range. Return a transient error. */
     rc = SQLITE_ERROR;
     sqlite3Error(db, SQLITE_ERROR, 0);
-  } else if( v==0 ){
+  }else if( v==0 ){
     /* If there is no statement handle, then the blob-handle has
     ** already been invalidated. Return SQLITE_ABORT in this case.
     */
@@ -54450,12 +70230,1091 @@ SQLITE_API int sqlite3_blob_write(sqlite3_blob *pBlob, const void *z, int n, int
 */
 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *pBlob){
   Incrblob *p = (Incrblob *)pBlob;
-  return p->nByte;
+  return (p && p->pStmt) ? p->nByte : 0;
+}
+
+/*
+** Move an existing blob handle to point to a different row of the same
+** database table.
+**
+** If an error occurs, or if the specified row does not exist or does not
+** contain a blob or text value, then an error code is returned and the
+** database handle error code and message set. If this happens, then all 
+** subsequent calls to sqlite3_blob_xxx() functions (except blob_close()) 
+** immediately return SQLITE_ABORT.
+*/
+SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *pBlob, sqlite3_int64 iRow){
+  int rc;
+  Incrblob *p = (Incrblob *)pBlob;
+  sqlite3 *db;
+
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+  db = p->db;
+  sqlite3_mutex_enter(db->mutex);
+
+  if( p->pStmt==0 ){
+    /* If there is no statement handle, then the blob-handle has
+    ** already been invalidated. Return SQLITE_ABORT in this case.
+    */
+    rc = SQLITE_ABORT;
+  }else{
+    char *zErr;
+    rc = blobSeekToRow(p, iRow, &zErr);
+    if( rc!=SQLITE_OK ){
+      sqlite3Error(db, rc, (zErr ? "%s" : 0), zErr);
+      sqlite3DbFree(db, zErr);
+    }
+    assert( rc!=SQLITE_SCHEMA );
+  }
+
+  rc = sqlite3ApiExit(db, rc);
+  assert( rc==SQLITE_OK || p->pStmt==0 );
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
 }
 
 #endif /* #ifndef SQLITE_OMIT_INCRBLOB */
 
 /************** End of vdbeblob.c ********************************************/
+/************** Begin file vdbesort.c ****************************************/
+/*
+** 2011 July 9
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code for the VdbeSorter object, used in concert with
+** a VdbeCursor to sort large numbers of keys (as may be required, for
+** example, by CREATE INDEX statements on tables too large to fit in main
+** memory).
+*/
+
+
+#ifndef SQLITE_OMIT_MERGE_SORT
+
+typedef struct VdbeSorterIter VdbeSorterIter;
+typedef struct SorterRecord SorterRecord;
+typedef struct FileWriter FileWriter;
+
+/*
+** NOTES ON DATA STRUCTURE USED FOR N-WAY MERGES:
+**
+** As keys are added to the sorter, they are written to disk in a series
+** of sorted packed-memory-arrays (PMAs). The size of each PMA is roughly
+** the same as the cache-size allowed for temporary databases. In order
+** to allow the caller to extract keys from the sorter in sorted order,
+** all PMAs currently stored on disk must be merged together. This comment
+** describes the data structure used to do so. The structure supports 
+** merging any number of arrays in a single pass with no redundant comparison 
+** operations.
+**
+** The aIter[] array contains an iterator for each of the PMAs being merged.
+** An aIter[] iterator either points to a valid key or else is at EOF. For 
+** the purposes of the paragraphs below, we assume that the array is actually 
+** N elements in size, where N is the smallest power of 2 greater to or equal 
+** to the number of iterators being merged. The extra aIter[] elements are 
+** treated as if they are empty (always at EOF).
+**
+** The aTree[] array is also N elements in size. The value of N is stored in
+** the VdbeSorter.nTree variable.
+**
+** The final (N/2) elements of aTree[] contain the results of comparing
+** pairs of iterator keys together. Element i contains the result of 
+** comparing aIter[2*i-N] and aIter[2*i-N+1]. Whichever key is smaller, the
+** aTree element is set to the index of it. 
+**
+** For the purposes of this comparison, EOF is considered greater than any
+** other key value. If the keys are equal (only possible with two EOF
+** values), it doesn't matter which index is stored.
+**
+** The (N/4) elements of aTree[] that preceed the final (N/2) described 
+** above contains the index of the smallest of each block of 4 iterators.
+** And so on. So that aTree[1] contains the index of the iterator that 
+** currently points to the smallest key value. aTree[0] is unused.
+**
+** Example:
+**
+**     aIter[0] -> Banana
+**     aIter[1] -> Feijoa
+**     aIter[2] -> Elderberry
+**     aIter[3] -> Currant
+**     aIter[4] -> Grapefruit
+**     aIter[5] -> Apple
+**     aIter[6] -> Durian
+**     aIter[7] -> EOF
+**
+**     aTree[] = { X, 5   0, 5    0, 3, 5, 6 }
+**
+** The current element is "Apple" (the value of the key indicated by 
+** iterator 5). When the Next() operation is invoked, iterator 5 will
+** be advanced to the next key in its segment. Say the next key is
+** "Eggplant":
+**
+**     aIter[5] -> Eggplant
+**
+** The contents of aTree[] are updated first by comparing the new iterator
+** 5 key to the current key of iterator 4 (still "Grapefruit"). The iterator
+** 5 value is still smaller, so aTree[6] is set to 5. And so on up the tree.
+** The value of iterator 6 - "Durian" - is now smaller than that of iterator
+** 5, so aTree[3] is set to 6. Key 0 is smaller than key 6 (Banana<Durian),
+** so the value written into element 1 of the array is 0. As follows:
+**
+**     aTree[] = { X, 0   0, 6    0, 3, 5, 6 }
+**
+** In other words, each time we advance to the next sorter element, log2(N)
+** key comparison operations are required, where N is the number of segments
+** being merged (rounded up to the next power of 2).
+*/
+struct VdbeSorter {
+  i64 iWriteOff;                  /* Current write offset within file pTemp1 */
+  i64 iReadOff;                   /* Current read offset within file pTemp1 */
+  int nInMemory;                  /* Current size of pRecord list as PMA */
+  int nTree;                      /* Used size of aTree/aIter (power of 2) */
+  int nPMA;                       /* Number of PMAs stored in pTemp1 */
+  int mnPmaSize;                  /* Minimum PMA size, in bytes */
+  int mxPmaSize;                  /* Maximum PMA size, in bytes.  0==no limit */
+  VdbeSorterIter *aIter;          /* Array of iterators to merge */
+  int *aTree;                     /* Current state of incremental merge */
+  sqlite3_file *pTemp1;           /* PMA file 1 */
+  SorterRecord *pRecord;          /* Head of in-memory record list */
+  UnpackedRecord *pUnpacked;      /* Used to unpack keys */
+};
+
+/*
+** The following type is an iterator for a PMA. It caches the current key in 
+** variables nKey/aKey. If the iterator is at EOF, pFile==0.
+*/
+struct VdbeSorterIter {
+  i64 iReadOff;                   /* Current read offset */
+  i64 iEof;                       /* 1 byte past EOF for this iterator */
+  int nAlloc;                     /* Bytes of space at aAlloc */
+  int nKey;                       /* Number of bytes in key */
+  sqlite3_file *pFile;            /* File iterator is reading from */
+  u8 *aAlloc;                     /* Allocated space */
+  u8 *aKey;                       /* Pointer to current key */
+  u8 *aBuffer;                    /* Current read buffer */
+  int nBuffer;                    /* Size of read buffer in bytes */
+};
+
+/*
+** An instance of this structure is used to organize the stream of records
+** being written to files by the merge-sort code into aligned, page-sized
+** blocks.  Doing all I/O in aligned page-sized blocks helps I/O to go
+** faster on many operating systems.
+*/
+struct FileWriter {
+  int eFWErr;                     /* Non-zero if in an error state */
+  u8 *aBuffer;                    /* Pointer to write buffer */
+  int nBuffer;                    /* Size of write buffer in bytes */
+  int iBufStart;                  /* First byte of buffer to write */
+  int iBufEnd;                    /* Last byte of buffer to write */
+  i64 iWriteOff;                  /* Offset of start of buffer in file */
+  sqlite3_file *pFile;            /* File to write to */
+};
+
+/*
+** A structure to store a single record. All in-memory records are connected
+** together into a linked list headed at VdbeSorter.pRecord using the 
+** SorterRecord.pNext pointer.
+*/
+struct SorterRecord {
+  void *pVal;
+  int nVal;
+  SorterRecord *pNext;
+};
+
+/* Minimum allowable value for the VdbeSorter.nWorking variable */
+#define SORTER_MIN_WORKING 10
+
+/* Maximum number of segments to merge in a single pass. */
+#define SORTER_MAX_MERGE_COUNT 16
+
+/*
+** Free all memory belonging to the VdbeSorterIter object passed as the second
+** argument. All structure fields are set to zero before returning.
+*/
+static void vdbeSorterIterZero(sqlite3 *db, VdbeSorterIter *pIter){
+  sqlite3DbFree(db, pIter->aAlloc);
+  sqlite3DbFree(db, pIter->aBuffer);
+  memset(pIter, 0, sizeof(VdbeSorterIter));
+}
+
+/*
+** Read nByte bytes of data from the stream of data iterated by object p.
+** If successful, set *ppOut to point to a buffer containing the data
+** and return SQLITE_OK. Otherwise, if an error occurs, return an SQLite
+** error code.
+**
+** The buffer indicated by *ppOut may only be considered valid until the
+** next call to this function.
+*/
+static int vdbeSorterIterRead(
+  sqlite3 *db,                    /* Database handle (for malloc) */
+  VdbeSorterIter *p,              /* Iterator */
+  int nByte,                      /* Bytes of data to read */
+  u8 **ppOut                      /* OUT: Pointer to buffer containing data */
+){
+  int iBuf;                       /* Offset within buffer to read from */
+  int nAvail;                     /* Bytes of data available in buffer */
+  assert( p->aBuffer );
+
+  /* If there is no more data to be read from the buffer, read the next 
+  ** p->nBuffer bytes of data from the file into it. Or, if there are less
+  ** than p->nBuffer bytes remaining in the PMA, read all remaining data.  */
+  iBuf = p->iReadOff % p->nBuffer;
+  if( iBuf==0 ){
+    int nRead;                    /* Bytes to read from disk */
+    int rc;                       /* sqlite3OsRead() return code */
+
+    /* Determine how many bytes of data to read. */
+    nRead = (int)(p->iEof - p->iReadOff);
+    if( nRead>p->nBuffer ) nRead = p->nBuffer;
+    assert( nRead>0 );
+
+    /* Read data from the file. Return early if an error occurs. */
+    rc = sqlite3OsRead(p->pFile, p->aBuffer, nRead, p->iReadOff);
+    assert( rc!=SQLITE_IOERR_SHORT_READ );
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  nAvail = p->nBuffer - iBuf; 
+
+  if( nByte<=nAvail ){
+    /* The requested data is available in the in-memory buffer. In this
+    ** case there is no need to make a copy of the data, just return a 
+    ** pointer into the buffer to the caller.  */
+    *ppOut = &p->aBuffer[iBuf];
+    p->iReadOff += nByte;
+  }else{
+    /* The requested data is not all available in the in-memory buffer.
+    ** In this case, allocate space at p->aAlloc[] to copy the requested
+    ** range into. Then return a copy of pointer p->aAlloc to the caller.  */
+    int nRem;                     /* Bytes remaining to copy */
+
+    /* Extend the p->aAlloc[] allocation if required. */
+    if( p->nAlloc<nByte ){
+      int nNew = p->nAlloc*2;
+      while( nByte>nNew ) nNew = nNew*2;
+      p->aAlloc = sqlite3DbReallocOrFree(db, p->aAlloc, nNew);
+      if( !p->aAlloc ) return SQLITE_NOMEM;
+      p->nAlloc = nNew;
+    }
+
+    /* Copy as much data as is available in the buffer into the start of
+    ** p->aAlloc[].  */
+    memcpy(p->aAlloc, &p->aBuffer[iBuf], nAvail);
+    p->iReadOff += nAvail;
+    nRem = nByte - nAvail;
+
+    /* The following loop copies up to p->nBuffer bytes per iteration into
+    ** the p->aAlloc[] buffer.  */
+    while( nRem>0 ){
+      int rc;                     /* vdbeSorterIterRead() return code */
+      int nCopy;                  /* Number of bytes to copy */
+      u8 *aNext;                  /* Pointer to buffer to copy data from */
+
+      nCopy = nRem;
+      if( nRem>p->nBuffer ) nCopy = p->nBuffer;
+      rc = vdbeSorterIterRead(db, p, nCopy, &aNext);
+      if( rc!=SQLITE_OK ) return rc;
+      assert( aNext!=p->aAlloc );
+      memcpy(&p->aAlloc[nByte - nRem], aNext, nCopy);
+      nRem -= nCopy;
+    }
+
+    *ppOut = p->aAlloc;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Read a varint from the stream of data accessed by p. Set *pnOut to
+** the value read.
+*/
+static int vdbeSorterIterVarint(sqlite3 *db, VdbeSorterIter *p, u64 *pnOut){
+  int iBuf;
+
+  iBuf = p->iReadOff % p->nBuffer;
+  if( iBuf && (p->nBuffer-iBuf)>=9 ){
+    p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut);
+  }else{
+    u8 aVarint[16], *a;
+    int i = 0, rc;
+    do{
+      rc = vdbeSorterIterRead(db, p, 1, &a);
+      if( rc ) return rc;
+      aVarint[(i++)&0xf] = a[0];
+    }while( (a[0]&0x80)!=0 );
+    sqlite3GetVarint(aVarint, pnOut);
+  }
+
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance iterator pIter to the next key in its PMA. Return SQLITE_OK if
+** no error occurs, or an SQLite error code if one does.
+*/
+static int vdbeSorterIterNext(
+  sqlite3 *db,                    /* Database handle (for sqlite3DbMalloc() ) */
+  VdbeSorterIter *pIter           /* Iterator to advance */
+){
+  int rc;                         /* Return Code */
+  u64 nRec = 0;                   /* Size of record in bytes */
+
+  if( pIter->iReadOff>=pIter->iEof ){
+    /* This is an EOF condition */
+    vdbeSorterIterZero(db, pIter);
+    return SQLITE_OK;
+  }
+
+  rc = vdbeSorterIterVarint(db, pIter, &nRec);
+  if( rc==SQLITE_OK ){
+    pIter->nKey = (int)nRec;
+    rc = vdbeSorterIterRead(db, pIter, (int)nRec, &pIter->aKey);
+  }
+
+  return rc;
+}
+
+/*
+** Initialize iterator pIter to scan through the PMA stored in file pFile
+** starting at offset iStart and ending at offset iEof-1. This function 
+** leaves the iterator pointing to the first key in the PMA (or EOF if the 
+** PMA is empty).
+*/
+static int vdbeSorterIterInit(
+  sqlite3 *db,                    /* Database handle */
+  const VdbeSorter *pSorter,      /* Sorter object */
+  i64 iStart,                     /* Start offset in pFile */
+  VdbeSorterIter *pIter,          /* Iterator to populate */
+  i64 *pnByte                     /* IN/OUT: Increment this value by PMA size */
+){
+  int rc = SQLITE_OK;
+  int nBuf;
+
+  nBuf = sqlite3BtreeGetPageSize(db->aDb[0].pBt);
+
+  assert( pSorter->iWriteOff>iStart );
+  assert( pIter->aAlloc==0 );
+  assert( pIter->aBuffer==0 );
+  pIter->pFile = pSorter->pTemp1;
+  pIter->iReadOff = iStart;
+  pIter->nAlloc = 128;
+  pIter->aAlloc = (u8 *)sqlite3DbMallocRaw(db, pIter->nAlloc);
+  pIter->nBuffer = nBuf;
+  pIter->aBuffer = (u8 *)sqlite3DbMallocRaw(db, nBuf);
+
+  if( !pIter->aBuffer ){
+    rc = SQLITE_NOMEM;
+  }else{
+    int iBuf;
+
+    iBuf = iStart % nBuf;
+    if( iBuf ){
+      int nRead = nBuf - iBuf;
+      if( (iStart + nRead) > pSorter->iWriteOff ){
+        nRead = (int)(pSorter->iWriteOff - iStart);
+      }
+      rc = sqlite3OsRead(
+          pSorter->pTemp1, &pIter->aBuffer[iBuf], nRead, iStart
+      );
+      assert( rc!=SQLITE_IOERR_SHORT_READ );
+    }
+
+    if( rc==SQLITE_OK ){
+      u64 nByte;                       /* Size of PMA in bytes */
+      pIter->iEof = pSorter->iWriteOff;
+      rc = vdbeSorterIterVarint(db, pIter, &nByte);
+      pIter->iEof = pIter->iReadOff + nByte;
+      *pnByte += nByte;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = vdbeSorterIterNext(db, pIter);
+  }
+  return rc;
+}
+
+
+/*
+** Compare key1 (buffer pKey1, size nKey1 bytes) with key2 (buffer pKey2, 
+** size nKey2 bytes).  Argument pKeyInfo supplies the collation functions
+** used by the comparison. If an error occurs, return an SQLite error code.
+** Otherwise, return SQLITE_OK and set *pRes to a negative, zero or positive
+** value, depending on whether key1 is smaller, equal to or larger than key2.
+**
+** If the bOmitRowid argument is non-zero, assume both keys end in a rowid
+** field. For the purposes of the comparison, ignore it. Also, if bOmitRowid
+** is true and key1 contains even a single NULL value, it is considered to
+** be less than key2. Even if key2 also contains NULL values.
+**
+** If pKey2 is passed a NULL pointer, then it is assumed that the pCsr->aSpace
+** has been allocated and contains an unpacked record that is used as key2.
+*/
+static void vdbeSorterCompare(
+  const VdbeCursor *pCsr,         /* Cursor object (for pKeyInfo) */
+  int bOmitRowid,                 /* Ignore rowid field at end of keys */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2,   /* Right side of comparison */
+  int *pRes                       /* OUT: Result of comparison */
+){
+  KeyInfo *pKeyInfo = pCsr->pKeyInfo;
+  VdbeSorter *pSorter = pCsr->pSorter;
+  UnpackedRecord *r2 = pSorter->pUnpacked;
+  int i;
+
+  if( pKey2 ){
+    sqlite3VdbeRecordUnpack(pKeyInfo, nKey2, pKey2, r2);
+  }
+
+  if( bOmitRowid ){
+    r2->nField = pKeyInfo->nField;
+    assert( r2->nField>0 );
+    for(i=0; i<r2->nField; i++){
+      if( r2->aMem[i].flags & MEM_Null ){
+        *pRes = -1;
+        return;
+      }
+    }
+    r2->flags |= UNPACKED_PREFIX_MATCH;
+  }
+
+  *pRes = sqlite3VdbeRecordCompare(nKey1, pKey1, r2);
+}
+
+/*
+** This function is called to compare two iterator keys when merging 
+** multiple b-tree segments. Parameter iOut is the index of the aTree[] 
+** value to recalculate.
+*/
+static int vdbeSorterDoCompare(const VdbeCursor *pCsr, int iOut){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  int i1;
+  int i2;
+  int iRes;
+  VdbeSorterIter *p1;
+  VdbeSorterIter *p2;
+
+  assert( iOut<pSorter->nTree && iOut>0 );
+
+  if( iOut>=(pSorter->nTree/2) ){
+    i1 = (iOut - pSorter->nTree/2) * 2;
+    i2 = i1 + 1;
+  }else{
+    i1 = pSorter->aTree[iOut*2];
+    i2 = pSorter->aTree[iOut*2+1];
+  }
+
+  p1 = &pSorter->aIter[i1];
+  p2 = &pSorter->aIter[i2];
+
+  if( p1->pFile==0 ){
+    iRes = i2;
+  }else if( p2->pFile==0 ){
+    iRes = i1;
+  }else{
+    int res;
+    assert( pCsr->pSorter->pUnpacked!=0 );  /* allocated in vdbeSorterMerge() */
+    vdbeSorterCompare(
+        pCsr, 0, p1->aKey, p1->nKey, p2->aKey, p2->nKey, &res
+    );
+    if( res<=0 ){
+      iRes = i1;
+    }else{
+      iRes = i2;
+    }
+  }
+
+  pSorter->aTree[iOut] = iRes;
+  return SQLITE_OK;
+}
+
+/*
+** Initialize the temporary index cursor just opened as a sorter cursor.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterInit(sqlite3 *db, VdbeCursor *pCsr){
+  int pgsz;                       /* Page size of main database */
+  int mxCache;                    /* Cache size */
+  VdbeSorter *pSorter;            /* The new sorter */
+  char *d;                        /* Dummy */
+
+  assert( pCsr->pKeyInfo && pCsr->pBt==0 );
+  pCsr->pSorter = pSorter = sqlite3DbMallocZero(db, sizeof(VdbeSorter));
+  if( pSorter==0 ){
+    return SQLITE_NOMEM;
+  }
+  
+  pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pCsr->pKeyInfo, 0, 0, &d);
+  if( pSorter->pUnpacked==0 ) return SQLITE_NOMEM;
+  assert( pSorter->pUnpacked==(UnpackedRecord *)d );
+
+  if( !sqlite3TempInMemory(db) ){
+    pgsz = sqlite3BtreeGetPageSize(db->aDb[0].pBt);
+    pSorter->mnPmaSize = SORTER_MIN_WORKING * pgsz;
+    mxCache = db->aDb[0].pSchema->cache_size;
+    if( mxCache<SORTER_MIN_WORKING ) mxCache = SORTER_MIN_WORKING;
+    pSorter->mxPmaSize = mxCache * pgsz;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Free the list of sorted records starting at pRecord.
+*/
+static void vdbeSorterRecordFree(sqlite3 *db, SorterRecord *pRecord){
+  SorterRecord *p;
+  SorterRecord *pNext;
+  for(p=pRecord; p; p=pNext){
+    pNext = p->pNext;
+    sqlite3DbFree(db, p);
+  }
+}
+
+/*
+** Free any cursor components allocated by sqlite3VdbeSorterXXX routines.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  if( pSorter ){
+    if( pSorter->aIter ){
+      int i;
+      for(i=0; i<pSorter->nTree; i++){
+        vdbeSorterIterZero(db, &pSorter->aIter[i]);
+      }
+      sqlite3DbFree(db, pSorter->aIter);
+    }
+    if( pSorter->pTemp1 ){
+      sqlite3OsCloseFree(pSorter->pTemp1);
+    }
+    vdbeSorterRecordFree(db, pSorter->pRecord);
+    sqlite3DbFree(db, pSorter->pUnpacked);
+    sqlite3DbFree(db, pSorter);
+    pCsr->pSorter = 0;
+  }
+}
+
+/*
+** Allocate space for a file-handle and open a temporary file. If successful,
+** set *ppFile to point to the malloc'd file-handle and return SQLITE_OK.
+** Otherwise, set *ppFile to 0 and return an SQLite error code.
+*/
+static int vdbeSorterOpenTempFile(sqlite3 *db, sqlite3_file **ppFile){
+  int dummy;
+  return sqlite3OsOpenMalloc(db->pVfs, 0, ppFile,
+      SQLITE_OPEN_TEMP_JOURNAL |
+      SQLITE_OPEN_READWRITE    | SQLITE_OPEN_CREATE |
+      SQLITE_OPEN_EXCLUSIVE    | SQLITE_OPEN_DELETEONCLOSE, &dummy
+  );
+}
+
+/*
+** Merge the two sorted lists p1 and p2 into a single list.
+** Set *ppOut to the head of the new list.
+*/
+static void vdbeSorterMerge(
+  const VdbeCursor *pCsr,         /* For pKeyInfo */
+  SorterRecord *p1,               /* First list to merge */
+  SorterRecord *p2,               /* Second list to merge */
+  SorterRecord **ppOut            /* OUT: Head of merged list */
+){
+  SorterRecord *pFinal = 0;
+  SorterRecord **pp = &pFinal;
+  void *pVal2 = p2 ? p2->pVal : 0;
+
+  while( p1 && p2 ){
+    int res;
+    vdbeSorterCompare(pCsr, 0, p1->pVal, p1->nVal, pVal2, p2->nVal, &res);
+    if( res<=0 ){
+      *pp = p1;
+      pp = &p1->pNext;
+      p1 = p1->pNext;
+      pVal2 = 0;
+    }else{
+      *pp = p2;
+       pp = &p2->pNext;
+      p2 = p2->pNext;
+      if( p2==0 ) break;
+      pVal2 = p2->pVal;
+    }
+  }
+  *pp = p1 ? p1 : p2;
+  *ppOut = pFinal;
+}
+
+/*
+** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK
+** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error
+** occurs.
+*/
+static int vdbeSorterSort(const VdbeCursor *pCsr){
+  int i;
+  SorterRecord **aSlot;
+  SorterRecord *p;
+  VdbeSorter *pSorter = pCsr->pSorter;
+
+  aSlot = (SorterRecord **)sqlite3MallocZero(64 * sizeof(SorterRecord *));
+  if( !aSlot ){
+    return SQLITE_NOMEM;
+  }
+
+  p = pSorter->pRecord;
+  while( p ){
+    SorterRecord *pNext = p->pNext;
+    p->pNext = 0;
+    for(i=0; aSlot[i]; i++){
+      vdbeSorterMerge(pCsr, p, aSlot[i], &p);
+      aSlot[i] = 0;
+    }
+    aSlot[i] = p;
+    p = pNext;
+  }
+
+  p = 0;
+  for(i=0; i<64; i++){
+    vdbeSorterMerge(pCsr, p, aSlot[i], &p);
+  }
+  pSorter->pRecord = p;
+
+  sqlite3_free(aSlot);
+  return SQLITE_OK;
+}
+
+/*
+** Initialize a file-writer object.
+*/
+static void fileWriterInit(
+  sqlite3 *db,                    /* Database (for malloc) */
+  sqlite3_file *pFile,            /* File to write to */
+  FileWriter *p,                  /* Object to populate */
+  i64 iStart                      /* Offset of pFile to begin writing at */
+){
+  int nBuf = sqlite3BtreeGetPageSize(db->aDb[0].pBt);
+
+  memset(p, 0, sizeof(FileWriter));
+  p->aBuffer = (u8 *)sqlite3DbMallocRaw(db, nBuf);
+  if( !p->aBuffer ){
+    p->eFWErr = SQLITE_NOMEM;
+  }else{
+    p->iBufEnd = p->iBufStart = (iStart % nBuf);
+    p->iWriteOff = iStart - p->iBufStart;
+    p->nBuffer = nBuf;
+    p->pFile = pFile;
+  }
+}
+
+/*
+** Write nData bytes of data to the file-write object. Return SQLITE_OK
+** if successful, or an SQLite error code if an error occurs.
+*/
+static void fileWriterWrite(FileWriter *p, u8 *pData, int nData){
+  int nRem = nData;
+  while( nRem>0 && p->eFWErr==0 ){
+    int nCopy = nRem;
+    if( nCopy>(p->nBuffer - p->iBufEnd) ){
+      nCopy = p->nBuffer - p->iBufEnd;
+    }
+
+    memcpy(&p->aBuffer[p->iBufEnd], &pData[nData-nRem], nCopy);
+    p->iBufEnd += nCopy;
+    if( p->iBufEnd==p->nBuffer ){
+      p->eFWErr = sqlite3OsWrite(p->pFile, 
+          &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart, 
+          p->iWriteOff + p->iBufStart
+      );
+      p->iBufStart = p->iBufEnd = 0;
+      p->iWriteOff += p->nBuffer;
+    }
+    assert( p->iBufEnd<p->nBuffer );
+
+    nRem -= nCopy;
+  }
+}
+
+/*
+** Flush any buffered data to disk and clean up the file-writer object.
+** The results of using the file-writer after this call are undefined.
+** Return SQLITE_OK if flushing the buffered data succeeds or is not 
+** required. Otherwise, return an SQLite error code.
+**
+** Before returning, set *piEof to the offset immediately following the
+** last byte written to the file.
+*/
+static int fileWriterFinish(sqlite3 *db, FileWriter *p, i64 *piEof){
+  int rc;
+  if( p->eFWErr==0 && ALWAYS(p->aBuffer) && p->iBufEnd>p->iBufStart ){
+    p->eFWErr = sqlite3OsWrite(p->pFile, 
+        &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart, 
+        p->iWriteOff + p->iBufStart
+    );
+  }
+  *piEof = (p->iWriteOff + p->iBufEnd);
+  sqlite3DbFree(db, p->aBuffer);
+  rc = p->eFWErr;
+  memset(p, 0, sizeof(FileWriter));
+  return rc;
+}
+
+/*
+** Write value iVal encoded as a varint to the file-write object. Return 
+** SQLITE_OK if successful, or an SQLite error code if an error occurs.
+*/
+static void fileWriterWriteVarint(FileWriter *p, u64 iVal){
+  int nByte; 
+  u8 aByte[10];
+  nByte = sqlite3PutVarint(aByte, iVal);
+  fileWriterWrite(p, aByte, nByte);
+}
+
+/*
+** Write the current contents of the in-memory linked-list to a PMA. Return
+** SQLITE_OK if successful, or an SQLite error code otherwise.
+**
+** The format of a PMA is:
+**
+**     * A varint. This varint contains the total number of bytes of content
+**       in the PMA (not including the varint itself).
+**
+**     * One or more records packed end-to-end in order of ascending keys. 
+**       Each record consists of a varint followed by a blob of data (the 
+**       key). The varint is the number of bytes in the blob of data.
+*/
+static int vdbeSorterListToPMA(sqlite3 *db, const VdbeCursor *pCsr){
+  int rc = SQLITE_OK;             /* Return code */
+  VdbeSorter *pSorter = pCsr->pSorter;
+  FileWriter writer;
+
+  memset(&writer, 0, sizeof(FileWriter));
+
+  if( pSorter->nInMemory==0 ){
+    assert( pSorter->pRecord==0 );
+    return rc;
+  }
+
+  rc = vdbeSorterSort(pCsr);
+
+  /* If the first temporary PMA file has not been opened, open it now. */
+  if( rc==SQLITE_OK && pSorter->pTemp1==0 ){
+    rc = vdbeSorterOpenTempFile(db, &pSorter->pTemp1);
+    assert( rc!=SQLITE_OK || pSorter->pTemp1 );
+    assert( pSorter->iWriteOff==0 );
+    assert( pSorter->nPMA==0 );
+  }
+
+  if( rc==SQLITE_OK ){
+    SorterRecord *p;
+    SorterRecord *pNext = 0;
+
+    fileWriterInit(db, pSorter->pTemp1, &writer, pSorter->iWriteOff);
+    pSorter->nPMA++;
+    fileWriterWriteVarint(&writer, pSorter->nInMemory);
+    for(p=pSorter->pRecord; p; p=pNext){
+      pNext = p->pNext;
+      fileWriterWriteVarint(&writer, p->nVal);
+      fileWriterWrite(&writer, p->pVal, p->nVal);
+      sqlite3DbFree(db, p);
+    }
+    pSorter->pRecord = p;
+    rc = fileWriterFinish(db, &writer, &pSorter->iWriteOff);
+  }
+
+  return rc;
+}
+
+/*
+** Add a record to the sorter.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterWrite(
+  sqlite3 *db,                    /* Database handle */
+  const VdbeCursor *pCsr,               /* Sorter cursor */
+  Mem *pVal                       /* Memory cell containing record */
+){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  int rc = SQLITE_OK;             /* Return Code */
+  SorterRecord *pNew;             /* New list element */
+
+  assert( pSorter );
+  pSorter->nInMemory += sqlite3VarintLen(pVal->n) + pVal->n;
+
+  pNew = (SorterRecord *)sqlite3DbMallocRaw(db, pVal->n + sizeof(SorterRecord));
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    pNew->pVal = (void *)&pNew[1];
+    memcpy(pNew->pVal, pVal->z, pVal->n);
+    pNew->nVal = pVal->n;
+    pNew->pNext = pSorter->pRecord;
+    pSorter->pRecord = pNew;
+  }
+
+  /* See if the contents of the sorter should now be written out. They
+  ** are written out when either of the following are true:
+  **
+  **   * The total memory allocated for the in-memory list is greater 
+  **     than (page-size * cache-size), or
+  **
+  **   * The total memory allocated for the in-memory list is greater 
+  **     than (page-size * 10) and sqlite3HeapNearlyFull() returns true.
+  */
+  if( rc==SQLITE_OK && pSorter->mxPmaSize>0 && (
+        (pSorter->nInMemory>pSorter->mxPmaSize)
+     || (pSorter->nInMemory>pSorter->mnPmaSize && sqlite3HeapNearlyFull())
+  )){
+#ifdef SQLITE_DEBUG
+    i64 nExpect = pSorter->iWriteOff
+                + sqlite3VarintLen(pSorter->nInMemory)
+                + pSorter->nInMemory;
+#endif
+    rc = vdbeSorterListToPMA(db, pCsr);
+    pSorter->nInMemory = 0;
+    assert( rc!=SQLITE_OK || (nExpect==pSorter->iWriteOff) );
+  }
+
+  return rc;
+}
+
+/*
+** Helper function for sqlite3VdbeSorterRewind(). 
+*/
+static int vdbeSorterInitMerge(
+  sqlite3 *db,                    /* Database handle */
+  const VdbeCursor *pCsr,         /* Cursor handle for this sorter */
+  i64 *pnByte                     /* Sum of bytes in all opened PMAs */
+){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Used to iterator through aIter[] */
+  i64 nByte = 0;                  /* Total bytes in all opened PMAs */
+
+  /* Initialize the iterators. */
+  for(i=0; i<SORTER_MAX_MERGE_COUNT; i++){
+    VdbeSorterIter *pIter = &pSorter->aIter[i];
+    rc = vdbeSorterIterInit(db, pSorter, pSorter->iReadOff, pIter, &nByte);
+    pSorter->iReadOff = pIter->iEof;
+    assert( rc!=SQLITE_OK || pSorter->iReadOff<=pSorter->iWriteOff );
+    if( rc!=SQLITE_OK || pSorter->iReadOff>=pSorter->iWriteOff ) break;
+  }
+
+  /* Initialize the aTree[] array. */
+  for(i=pSorter->nTree-1; rc==SQLITE_OK && i>0; i--){
+    rc = vdbeSorterDoCompare(pCsr, i);
+  }
+
+  *pnByte = nByte;
+  return rc;
+}
+
+/*
+** Once the sorter has been populated, this function is called to prepare
+** for iterating through its contents in sorted order.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterRewind(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  int rc;                         /* Return code */
+  sqlite3_file *pTemp2 = 0;       /* Second temp file to use */
+  i64 iWrite2 = 0;                /* Write offset for pTemp2 */
+  int nIter;                      /* Number of iterators used */
+  int nByte;                      /* Bytes of space required for aIter/aTree */
+  int N = 2;                      /* Power of 2 >= nIter */
+
+  assert( pSorter );
+
+  /* If no data has been written to disk, then do not do so now. Instead,
+  ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly
+  ** from the in-memory list.  */
+  if( pSorter->nPMA==0 ){
+    *pbEof = !pSorter->pRecord;
+    assert( pSorter->aTree==0 );
+    return vdbeSorterSort(pCsr);
+  }
+
+  /* Write the current in-memory list to a PMA. */
+  rc = vdbeSorterListToPMA(db, pCsr);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Allocate space for aIter[] and aTree[]. */
+  nIter = pSorter->nPMA;
+  if( nIter>SORTER_MAX_MERGE_COUNT ) nIter = SORTER_MAX_MERGE_COUNT;
+  assert( nIter>0 );
+  while( N<nIter ) N += N;
+  nByte = N * (sizeof(int) + sizeof(VdbeSorterIter));
+  pSorter->aIter = (VdbeSorterIter *)sqlite3DbMallocZero(db, nByte);
+  if( !pSorter->aIter ) return SQLITE_NOMEM;
+  pSorter->aTree = (int *)&pSorter->aIter[N];
+  pSorter->nTree = N;
+
+  do {
+    int iNew;                     /* Index of new, merged, PMA */
+
+    for(iNew=0; 
+        rc==SQLITE_OK && iNew*SORTER_MAX_MERGE_COUNT<pSorter->nPMA; 
+        iNew++
+    ){
+      int rc2;                    /* Return code from fileWriterFinish() */
+      FileWriter writer;          /* Object used to write to disk */
+      i64 nWrite;                 /* Number of bytes in new PMA */
+
+      memset(&writer, 0, sizeof(FileWriter));
+
+      /* If there are SORTER_MAX_MERGE_COUNT or less PMAs in file pTemp1,
+      ** initialize an iterator for each of them and break out of the loop.
+      ** These iterators will be incrementally merged as the VDBE layer calls
+      ** sqlite3VdbeSorterNext().
+      **
+      ** Otherwise, if pTemp1 contains more than SORTER_MAX_MERGE_COUNT PMAs,
+      ** initialize interators for SORTER_MAX_MERGE_COUNT of them. These PMAs
+      ** are merged into a single PMA that is written to file pTemp2.
+      */
+      rc = vdbeSorterInitMerge(db, pCsr, &nWrite);
+      assert( rc!=SQLITE_OK || pSorter->aIter[ pSorter->aTree[1] ].pFile );
+      if( rc!=SQLITE_OK || pSorter->nPMA<=SORTER_MAX_MERGE_COUNT ){
+        break;
+      }
+
+      /* Open the second temp file, if it is not already open. */
+      if( pTemp2==0 ){
+        assert( iWrite2==0 );
+        rc = vdbeSorterOpenTempFile(db, &pTemp2);
+      }
+
+      if( rc==SQLITE_OK ){
+        int bEof = 0;
+        fileWriterInit(db, pTemp2, &writer, iWrite2);
+        fileWriterWriteVarint(&writer, nWrite);
+        while( rc==SQLITE_OK && bEof==0 ){
+          VdbeSorterIter *pIter = &pSorter->aIter[ pSorter->aTree[1] ];
+          assert( pIter->pFile );
+
+          fileWriterWriteVarint(&writer, pIter->nKey);
+          fileWriterWrite(&writer, pIter->aKey, pIter->nKey);
+          rc = sqlite3VdbeSorterNext(db, pCsr, &bEof);
+        }
+        rc2 = fileWriterFinish(db, &writer, &iWrite2);
+        if( rc==SQLITE_OK ) rc = rc2;
+      }
+    }
+
+    if( pSorter->nPMA<=SORTER_MAX_MERGE_COUNT ){
+      break;
+    }else{
+      sqlite3_file *pTmp = pSorter->pTemp1;
+      pSorter->nPMA = iNew;
+      pSorter->pTemp1 = pTemp2;
+      pTemp2 = pTmp;
+      pSorter->iWriteOff = iWrite2;
+      pSorter->iReadOff = 0;
+      iWrite2 = 0;
+    }
+  }while( rc==SQLITE_OK );
+
+  if( pTemp2 ){
+    sqlite3OsCloseFree(pTemp2);
+  }
+  *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0);
+  return rc;
+}
+
+/*
+** Advance to the next element in the sorter.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  int rc;                         /* Return code */
+
+  if( pSorter->aTree ){
+    int iPrev = pSorter->aTree[1];/* Index of iterator to advance */
+    int i;                        /* Index of aTree[] to recalculate */
+
+    rc = vdbeSorterIterNext(db, &pSorter->aIter[iPrev]);
+    for(i=(pSorter->nTree+iPrev)/2; rc==SQLITE_OK && i>0; i=i/2){
+      rc = vdbeSorterDoCompare(pCsr, i);
+    }
+
+    *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0);
+  }else{
+    SorterRecord *pFree = pSorter->pRecord;
+    pSorter->pRecord = pFree->pNext;
+    pFree->pNext = 0;
+    vdbeSorterRecordFree(db, pFree);
+    *pbEof = !pSorter->pRecord;
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+/*
+** Return a pointer to a buffer owned by the sorter that contains the 
+** current key.
+*/
+static void *vdbeSorterRowkey(
+  const VdbeSorter *pSorter,      /* Sorter object */
+  int *pnKey                      /* OUT: Size of current key in bytes */
+){
+  void *pKey;
+  if( pSorter->aTree ){
+    VdbeSorterIter *pIter;
+    pIter = &pSorter->aIter[ pSorter->aTree[1] ];
+    *pnKey = pIter->nKey;
+    pKey = pIter->aKey;
+  }else{
+    *pnKey = pSorter->pRecord->nVal;
+    pKey = pSorter->pRecord->pVal;
+  }
+  return pKey;
+}
+
+/*
+** Copy the current sorter key into the memory cell pOut.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *pCsr, Mem *pOut){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  void *pKey; int nKey;           /* Sorter key to copy into pOut */
+
+  pKey = vdbeSorterRowkey(pSorter, &nKey);
+  if( sqlite3VdbeMemGrow(pOut, nKey, 0) ){
+    return SQLITE_NOMEM;
+  }
+  pOut->n = nKey;
+  MemSetTypeFlag(pOut, MEM_Blob);
+  memcpy(pOut->z, pKey, nKey);
+
+  return SQLITE_OK;
+}
+
+/*
+** Compare the key in memory cell pVal with the key that the sorter cursor
+** passed as the first argument currently points to. For the purposes of
+** the comparison, ignore the rowid field at the end of each record.
+**
+** If an error occurs, return an SQLite error code (i.e. SQLITE_NOMEM).
+** Otherwise, set *pRes to a negative, zero or positive value if the
+** key in pVal is smaller than, equal to or larger than the current sorter
+** key.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterCompare(
+  const VdbeCursor *pCsr,         /* Sorter cursor */
+  Mem *pVal,                      /* Value to compare to current sorter key */
+  int *pRes                       /* OUT: Result of comparison */
+){
+  VdbeSorter *pSorter = pCsr->pSorter;
+  void *pKey; int nKey;           /* Sorter key to compare pVal with */
+
+  pKey = vdbeSorterRowkey(pSorter, &nKey);
+  vdbeSorterCompare(pCsr, 1, pVal->z, pVal->n, pKey, nKey, pRes);
+  return SQLITE_OK;
+}
+
+#endif /* #ifndef SQLITE_OMIT_MERGE_SORT */
+
+/************** End of vdbesort.c ********************************************/
 /************** Begin file journal.c *****************************************/
 /*
 ** 2007 August 22
@@ -54469,12 +71328,6 @@ SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *pBlob){
 **
 *************************************************************************
 **
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
-*/
-
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
-
-/*
 ** This file implements a special kind of sqlite3_file object used
 ** by SQLite to create journal files if the atomic-write optimization
 ** is enabled.
@@ -54487,9 +71340,9 @@ SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *pBlob){
 **
 **   1) The in-memory representation grows too large for the allocated 
 **      buffer, or
-**   2) The xSync() method is called.
+**   2) The sqlite3JournalCreate() function is called.
 */
-
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
 
 
 /*
@@ -54553,8 +71406,9 @@ static int jrnlRead(
   JournalFile *p = (JournalFile *)pJfd;
   if( p->pReal ){
     rc = sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst);
+  }else if( (iAmt+iOfst)>p->iSize ){
+    rc = SQLITE_IOERR_SHORT_READ;
   }else{
-    assert( iAmt+iOfst<=p->iSize );
     memcpy(zBuf, &p->zBuf[iOfst], iAmt);
   }
   return rc;
@@ -54645,7 +71499,11 @@ static struct sqlite3_io_methods JournalFileMethods = {
   0,             /* xCheckReservedLock */
   0,             /* xFileControl */
   0,             /* xSectorSize */
-  0              /* xDeviceCharacteristics */
+  0,             /* xDeviceCharacteristics */
+  0,             /* xShmMap */
+  0,             /* xShmLock */
+  0,             /* xShmBarrier */
+  0              /* xShmUnmap */
 };
 
 /* 
@@ -54713,8 +71571,6 @@ SQLITE_PRIVATE int sqlite3JournalSize(sqlite3_vfs *pVfs){
 ** This file contains code use to implement an in-memory rollback journal.
 ** The in-memory rollback journal is used to journal transactions for
 ** ":memory:" databases and when the journal_mode=MEMORY pragma is used.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /* Forward references to internal structures */
@@ -54724,8 +71580,13 @@ typedef struct FileChunk FileChunk;
 
 /* Space to hold the rollback journal is allocated in increments of
 ** this many bytes.
+**
+** The size chosen is a little less than a power of two.  That way,
+** the FileChunk object will have a size that almost exactly fills
+** a power-of-two allocation.  This mimimizes wasted space in power-of-two
+** memory allocators.
 */
-#define JOURNAL_CHUNKSIZE 1024
+#define JOURNAL_CHUNKSIZE ((int)(1024-sizeof(FileChunk*)))
 
 /* Macro to find the minimum of two numeric values.
 */
@@ -54762,7 +71623,8 @@ struct MemJournal {
 };
 
 /*
-** Read data from the file.
+** Read data from the in-memory journal file.  This is the implementation
+** of the sqlite3_vfs.xRead method.
 */
 static int memjrnlRead(
   sqlite3_file *pJfd,    /* The journal file from which to read */
@@ -54776,12 +71638,13 @@ static int memjrnlRead(
   int iChunkOffset;
   FileChunk *pChunk;
 
+  /* SQLite never tries to read past the end of a rollback journal file */
   assert( iOfst+iAmt<=p->endpoint.iOffset );
 
   if( p->readpoint.iOffset!=iOfst || iOfst==0 ){
     sqlite3_int64 iOff = 0;
     for(pChunk=p->pFirst; 
-        pChunk && (iOff+JOURNAL_CHUNKSIZE)<=iOfst;
+        ALWAYS(pChunk) && (iOff+JOURNAL_CHUNKSIZE)<=iOfst;
         pChunk=pChunk->pNext
     ){
       iOff += JOURNAL_CHUNKSIZE;
@@ -54821,7 +71684,7 @@ static int memjrnlWrite(
   /* An in-memory journal file should only ever be appended to. Random
   ** access writes are not required by sqlite.
   */
-  assert(iOfst==p->endpoint.iOffset);
+  assert( iOfst==p->endpoint.iOffset );
   UNUSED_PARAMETER(iOfst);
 
   while( nWrite>0 ){
@@ -54884,6 +71747,11 @@ static int memjrnlClose(sqlite3_file *pJfd){
 
 /*
 ** Sync the file.
+**
+** Syncing an in-memory journal is a no-op.  And, in fact, this routine
+** is never called in a working implementation.  This implementation
+** exists purely as a contingency, in case some malfunction in some other
+** part of SQLite causes Sync to be called by mistake.
 */
 static int memjrnlSync(sqlite3_file *NotUsed, int NotUsed2){
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
@@ -54902,7 +71770,7 @@ static int memjrnlFileSize(sqlite3_file *pJfd, sqlite_int64 *pSize){
 /*
 ** Table of methods for MemJournal sqlite3_file object.
 */
-static struct sqlite3_io_methods MemJournalMethods = {
+static const struct sqlite3_io_methods MemJournalMethods = {
   1,                /* iVersion */
   memjrnlClose,     /* xClose */
   memjrnlRead,      /* xRead */
@@ -54915,7 +71783,11 @@ static struct sqlite3_io_methods MemJournalMethods = {
   0,                /* xCheckReservedLock */
   0,                /* xFileControl */
   0,                /* xSectorSize */
-  0                 /* xDeviceCharacteristics */
+  0,                /* xDeviceCharacteristics */
+  0,                /* xShmMap */
+  0,                /* xShmLock */
+  0,                /* xShmBarrier */
+  0                 /* xShmUnlock */
 };
 
 /* 
@@ -54923,8 +71795,9 @@ static struct sqlite3_io_methods MemJournalMethods = {
 */
 SQLITE_PRIVATE void sqlite3MemJournalOpen(sqlite3_file *pJfd){
   MemJournal *p = (MemJournal *)pJfd;
+  assert( EIGHT_BYTE_ALIGNMENT(p) );
   memset(p, 0, sqlite3MemJournalSize());
-  p->pMethod = &MemJournalMethods;
+  p->pMethod = (sqlite3_io_methods*)&MemJournalMethods;
 }
 
 /*
@@ -54936,8 +71809,7 @@ SQLITE_PRIVATE int sqlite3IsMemJournal(sqlite3_file *pJfd){
 }
 
 /* 
-** Return the number of bytes required to store a MemJournal that uses vfs
-** pVfs to create the underlying on-disk files.
+** Return the number of bytes required to store a MemJournal file descriptor.
 */
 SQLITE_PRIVATE int sqlite3MemJournalSize(void){
   return sizeof(MemJournal);
@@ -54958,9 +71830,9 @@ SQLITE_PRIVATE int sqlite3MemJournalSize(void){
 *************************************************************************
 ** This file contains routines used for walking the parser tree for
 ** an SQL statement.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/* #include <stdlib.h> */
+/* #include <string.h> */
 
 
 /*
@@ -54985,13 +71857,17 @@ SQLITE_PRIVATE int sqlite3MemJournalSize(void){
 SQLITE_PRIVATE int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
   int rc;
   if( pExpr==0 ) return WRC_Continue;
+  testcase( ExprHasProperty(pExpr, EP_TokenOnly) );
+  testcase( ExprHasProperty(pExpr, EP_Reduced) );
   rc = pWalker->xExprCallback(pWalker, pExpr);
-  if( rc==WRC_Continue ){
+  if( rc==WRC_Continue
+              && !ExprHasAnyProperty(pExpr,EP_TokenOnly) ){
     if( sqlite3WalkExpr(pWalker, pExpr->pLeft) ) return WRC_Abort;
     if( sqlite3WalkExpr(pWalker, pExpr->pRight) ) return WRC_Abort;
-    if( sqlite3WalkExprList(pWalker, pExpr->pList) ) return WRC_Abort;
-    if( sqlite3WalkSelect(pWalker, pExpr->pSelect) ){
-      return WRC_Abort;
+    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+      if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
+    }else{
+      if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
     }
   }
   return rc & WRC_Abort;
@@ -55002,14 +71878,14 @@ SQLITE_PRIVATE int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
 ** an abort request is seen.
 */
 SQLITE_PRIVATE int sqlite3WalkExprList(Walker *pWalker, ExprList *p){
-  int i, rc = WRC_Continue;
+  int i;
   struct ExprList_item *pItem;
   if( p ){
     for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){
       if( sqlite3WalkExpr(pWalker, pItem->pExpr) ) return WRC_Abort;
     }
   }
-  return rc & WRC_Continue;
+  return WRC_Continue;
 }
 
 /*
@@ -55042,7 +71918,7 @@ SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
   struct SrcList_item *pItem;
 
   pSrc = p->pSrc;
-  if( pSrc ){
+  if( ALWAYS(pSrc) ){
     for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
       if( sqlite3WalkSelect(pWalker, pItem->pSelect) ){
         return WRC_Abort;
@@ -55067,13 +71943,19 @@ SQLITE_PRIVATE int sqlite3WalkSelect(Walker *pWalker, Select *p){
   int rc;
   if( p==0 || pWalker->xSelectCallback==0 ) return WRC_Continue;
   rc = WRC_Continue;
-  while( p  ){
+  pWalker->walkerDepth++;
+  while( p ){
     rc = pWalker->xSelectCallback(pWalker, p);
     if( rc ) break;
-    if( sqlite3WalkSelectExpr(pWalker, p) ) return WRC_Abort;
-    if( sqlite3WalkSelectFrom(pWalker, p) ) return WRC_Abort;
+    if( sqlite3WalkSelectExpr(pWalker, p)
+     || sqlite3WalkSelectFrom(pWalker, p)
+    ){
+      pWalker->walkerDepth--;
+      return WRC_Abort;
+    }
     p = p->pPrior;
   }
+  pWalker->walkerDepth--;
   return rc & WRC_Abort;
 }
 
@@ -55094,9 +71976,32 @@ SQLITE_PRIVATE int sqlite3WalkSelect(Walker *pWalker, Select *p){
 ** This file contains routines used for walking the parser tree and
 ** resolve all identifiers by associating them with a particular
 ** table and column.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/* #include <stdlib.h> */
+/* #include <string.h> */
+
+/*
+** Walk the expression tree pExpr and increase the aggregate function
+** depth (the Expr.op2 field) by N on every TK_AGG_FUNCTION node.
+** This needs to occur when copying a TK_AGG_FUNCTION node from an
+** outer query into an inner subquery.
+**
+** incrAggFunctionDepth(pExpr,n) is the main routine.  incrAggDepth(..)
+** is a helper function - a callback for the tree walker.
+*/
+static int incrAggDepth(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_AGG_FUNCTION ) pExpr->op2 += pWalker->u.i;
+  return WRC_Continue;
+}
+static void incrAggFunctionDepth(Expr *pExpr, int N){
+  if( N>0 ){
+    Walker w;
+    memset(&w, 0, sizeof(w));
+    w.xExprCallback = incrAggDepth;
+    w.u.i = N;
+    sqlite3WalkExpr(&w, pExpr);
+  }
+}
 
 /*
 ** Turn the pExpr expression into an alias for the iCol-th column of the
@@ -55124,13 +72029,20 @@ SQLITE_PRIVATE int sqlite3WalkSelect(Walker *pWalker, Select *p){
 ** The result of random()%5 in the GROUP BY clause is probably different
 ** from the result in the result-set.  We might fix this someday.  Or
 ** then again, we might not...
+**
+** The nSubquery parameter specifies how many levels of subquery the
+** alias is removed from the original expression.  The usually value is
+** zero but it might be more if the alias is contained within a subquery
+** of the original expression.  The Expr.op2 field of TK_AGG_FUNCTION
+** structures must be increased by the nSubquery amount.
 */
 static void resolveAlias(
   Parse *pParse,         /* Parsing context */
   ExprList *pEList,      /* A result set */
   int iCol,              /* A column in the result set.  0..pEList->nExpr-1 */
   Expr *pExpr,           /* Transform this into an alias to the result set */
-  const char *zType      /* "GROUP" or "ORDER" or "" */
+  const char *zType,     /* "GROUP" or "ORDER" or "" */
+  int nSubquery          /* Number of subqueries that the label is moving */
 ){
   Expr *pOrig;           /* The iCol-th column of the result set */
   Expr *pDup;            /* Copy of pOrig */
@@ -55141,25 +72053,62 @@ static void resolveAlias(
   assert( pOrig!=0 );
   assert( pOrig->flags & EP_Resolved );
   db = pParse->db;
-  pDup = sqlite3ExprDup(db, pOrig);
-  if( pDup==0 ) return;
-  if( pDup->op!=TK_COLUMN && zType[0]!='G' ){
+  if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
+    pDup = sqlite3ExprDup(db, pOrig, 0);
+    incrAggFunctionDepth(pDup, nSubquery);
     pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
     if( pDup==0 ) return;
     if( pEList->a[iCol].iAlias==0 ){
       pEList->a[iCol].iAlias = (u16)(++pParse->nAlias);
     }
     pDup->iTable = pEList->a[iCol].iAlias;
+  }else if( ExprHasProperty(pOrig, EP_IntValue) || pOrig->u.zToken==0 ){
+    pDup = sqlite3ExprDup(db, pOrig, 0);
+    if( pDup==0 ) return;
+  }else{
+    char *zToken = pOrig->u.zToken;
+    assert( zToken!=0 );
+    pOrig->u.zToken = 0;
+    pDup = sqlite3ExprDup(db, pOrig, 0);
+    pOrig->u.zToken = zToken;
+    if( pDup==0 ) return;
+    assert( (pDup->flags & (EP_Reduced|EP_TokenOnly))==0 );
+    pDup->flags2 |= EP2_MallocedToken;
+    pDup->u.zToken = sqlite3DbStrDup(db, zToken);
   }
   if( pExpr->flags & EP_ExpCollate ){
     pDup->pColl = pExpr->pColl;
     pDup->flags |= EP_ExpCollate;
   }
-  sqlite3ExprClear(db, pExpr);
+
+  /* Before calling sqlite3ExprDelete(), set the EP_Static flag. This 
+  ** prevents ExprDelete() from deleting the Expr structure itself,
+  ** allowing it to be repopulated by the memcpy() on the following line.
+  */
+  ExprSetProperty(pExpr, EP_Static);
+  sqlite3ExprDelete(db, pExpr);
   memcpy(pExpr, pDup, sizeof(*pExpr));
   sqlite3DbFree(db, pDup);
 }
 
+
+/*
+** Return TRUE if the name zCol occurs anywhere in the USING clause.
+**
+** Return FALSE if the USING clause is NULL or if it does not contain
+** zCol.
+*/
+static int nameInUsingClause(IdList *pUsing, const char *zCol){
+  if( pUsing ){
+    int k;
+    for(k=0; k<pUsing->nId; k++){
+      if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ) return 1;
+    }
+  }
+  return 0;
+}
+
+
 /*
 ** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
 ** that name in the set of source tables in pSrcList and make the pExpr 
@@ -55177,49 +72126,43 @@ static void resolveAlias(
 **    pExpr->pLeft         Any expression this points to is deleted
 **    pExpr->pRight        Any expression this points to is deleted.
 **
-** The pDbToken is the name of the database (the "X").  This value may be
+** The zDb variable is the name of the database (the "X").  This value may be
 ** NULL meaning that name is of the form Y.Z or Z.  Any available database
-** can be used.  The pTableToken is the name of the table (the "Y").  This
-** value can be NULL if pDbToken is also NULL.  If pTableToken is NULL it
+** can be used.  The zTable variable is the name of the table (the "Y").  This
+** value can be NULL if zDb is also NULL.  If zTable is NULL it
 ** means that the form of the name is Z and that columns from any table
 ** can be used.
 **
 ** If the name cannot be resolved unambiguously, leave an error message
-** in pParse and return non-zero.  Return zero on success.
+** in pParse and return WRC_Abort.  Return WRC_Prune on success.
 */
 static int lookupName(
   Parse *pParse,       /* The parsing context */
-  Token *pDbToken,     /* Name of the database containing table, or NULL */
-  Token *pTableToken,  /* Name of table containing column, or NULL */
-  Token *pColumnToken, /* Name of the column. */
+  const char *zDb,     /* Name of the database containing table, or NULL */
+  const char *zTab,    /* Name of table containing column, or NULL */
+  const char *zCol,    /* Name of the column. */
   NameContext *pNC,    /* The name context used to resolve the name */
   Expr *pExpr          /* Make this EXPR node point to the selected column */
 ){
-  char *zDb = 0;       /* Name of the database.  The "X" in X.Y.Z */
-  char *zTab = 0;      /* Name of the table.  The "Y" in X.Y.Z or Y.Z */
-  char *zCol = 0;      /* Name of the column.  The "Z" */
-  int i, j;            /* Loop counters */
+  int i, j;                         /* Loop counters */
   int cnt = 0;                      /* Number of matching column names */
   int cntTab = 0;                   /* Number of matching table names */
+  int nSubquery = 0;                /* How many levels of subquery */
   sqlite3 *db = pParse->db;         /* The database connection */
   struct SrcList_item *pItem;       /* Use for looping over pSrcList items */
   struct SrcList_item *pMatch = 0;  /* The matching pSrcList item */
   NameContext *pTopNC = pNC;        /* First namecontext in the list */
   Schema *pSchema = 0;              /* Schema of the expression */
+  int isTrigger = 0;
 
-  assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
-
-  /* Dequote and zero-terminate the names */
-  zDb = sqlite3NameFromToken(db, pDbToken);
-  zTab = sqlite3NameFromToken(db, pTableToken);
-  zCol = sqlite3NameFromToken(db, pColumnToken);
-  if( db->mallocFailed ){
-    goto lookupname_end;
-  }
+  assert( pNC );     /* the name context cannot be NULL. */
+  assert( zCol );    /* The Z in X.Y.Z cannot be NULL */
+  assert( ~ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_Reduced) );
 
   /* Initialize the node to no-match */
   pExpr->iTable = -1;
   pExpr->pTab = 0;
+  ExprSetIrreducible(pExpr);
 
   /* Start at the inner-most context and move outward until a match is found */
   while( pNC && cnt==0 ){
@@ -55242,7 +72185,9 @@ static int lookupName(
             if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
           }else{
             char *zTabName = pTab->zName;
-            if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
+            if( NEVER(zTabName==0) || sqlite3StrICmp(zTabName, zTab)!=0 ){
+              continue;
+            }
             if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){
               continue;
             }
@@ -55256,34 +72201,21 @@ static int lookupName(
         }
         for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
           if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
-            IdList *pUsing;
+            /* If there has been exactly one prior match and this match
+            ** is for the right-hand table of a NATURAL JOIN or is in a 
+            ** USING clause, then skip this match.
+            */
+            if( cnt==1 ){
+              if( pItem->jointype & JT_NATURAL ) continue;
+              if( nameInUsingClause(pItem->pUsing, zCol) ) continue;
+            }
             cnt++;
             pExpr->iTable = pItem->iCursor;
             pExpr->pTab = pTab;
             pMatch = pItem;
             pSchema = pTab->pSchema;
             /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
-            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
-            if( i<pSrcList->nSrc-1 ){
-              if( pItem[1].jointype & JT_NATURAL ){
-                /* If this match occurred in the left table of a natural join,
-                ** then skip the right table to avoid a duplicate match */
-                pItem++;
-                i++;
-              }else if( (pUsing = pItem[1].pUsing)!=0 ){
-                /* If this match occurs on a column that is in the USING clause
-                ** of a join, skip the search of the right table of the join
-                ** to avoid a duplicate match there. */
-                int k;
-                for(k=0; k<pUsing->nId; k++){
-                  if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
-                    pItem++;
-                    i++;
-                    break;
-                  }
-                }
-              }
-            }
+            pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
             break;
           }
         }
@@ -55294,41 +72226,51 @@ static int lookupName(
     /* If we have not already resolved the name, then maybe 
     ** it is a new.* or old.* trigger argument reference
     */
-    if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){
-      TriggerStack *pTriggerStack = pParse->trigStack;
+    if( zDb==0 && zTab!=0 && cnt==0 && pParse->pTriggerTab!=0 ){
+      int op = pParse->eTriggerOp;
       Table *pTab = 0;
-      u32 *piColMask = 0;
-      if( pTriggerStack->newIdx != -1 && sqlite3StrICmp("new", zTab) == 0 ){
-        pExpr->iTable = pTriggerStack->newIdx;
-        assert( pTriggerStack->pTab );
-        pTab = pTriggerStack->pTab;
-        piColMask = &(pTriggerStack->newColMask);
-      }else if( pTriggerStack->oldIdx != -1 && sqlite3StrICmp("old", zTab)==0 ){
-        pExpr->iTable = pTriggerStack->oldIdx;
-        assert( pTriggerStack->pTab );
-        pTab = pTriggerStack->pTab;
-        piColMask = &(pTriggerStack->oldColMask);
+      assert( op==TK_DELETE || op==TK_UPDATE || op==TK_INSERT );
+      if( op!=TK_DELETE && sqlite3StrICmp("new",zTab) == 0 ){
+        pExpr->iTable = 1;
+        pTab = pParse->pTriggerTab;
+      }else if( op!=TK_INSERT && sqlite3StrICmp("old",zTab)==0 ){
+        pExpr->iTable = 0;
+        pTab = pParse->pTriggerTab;
       }
 
       if( pTab ){ 
         int iCol;
-        Column *pCol = pTab->aCol;
-
         pSchema = pTab->pSchema;
         cntTab++;
-        for(iCol=0; iCol < pTab->nCol; iCol++, pCol++) {
+        for(iCol=0; iCol<pTab->nCol; iCol++){
+          Column *pCol = &pTab->aCol[iCol];
           if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
-            cnt++;
-            pExpr->iColumn = iCol==pTab->iPKey ? -1 : iCol;
-            pExpr->pTab = pTab;
-            if( iCol>=0 ){
-              testcase( iCol==31 );
-              testcase( iCol==32 );
-              *piColMask |= ((u32)1<<iCol) | (iCol>=32?0xffffffff:0);
+            if( iCol==pTab->iPKey ){
+              iCol = -1;
             }
             break;
           }
         }
+        if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) ){
+          iCol = -1;        /* IMP: R-44911-55124 */
+        }
+        if( iCol<pTab->nCol ){
+          cnt++;
+          if( iCol<0 ){
+            pExpr->affinity = SQLITE_AFF_INTEGER;
+          }else if( pExpr->iTable==0 ){
+            testcase( iCol==31 );
+            testcase( iCol==32 );
+            pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
+          }else{
+            testcase( iCol==31 );
+            testcase( iCol==32 );
+            pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
+          }
+          pExpr->iColumn = (i16)iCol;
+          pExpr->pTab = pTab;
+          isTrigger = 1;
+        }
       }
     }
 #endif /* !defined(SQLITE_OMIT_TRIGGER) */
@@ -55338,7 +72280,7 @@ static int lookupName(
     */
     if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
       cnt = 1;
-      pExpr->iColumn = -1;
+      pExpr->iColumn = -1;     /* IMP: R-44911-55124 */
       pExpr->affinity = SQLITE_AFF_INTEGER;
     }
 
@@ -55360,19 +72302,18 @@ static int lookupName(
         if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
           Expr *pOrig;
           assert( pExpr->pLeft==0 && pExpr->pRight==0 );
-          assert( pExpr->pList==0 );
-          assert( pExpr->pSelect==0 );
+          assert( pExpr->x.pList==0 );
+          assert( pExpr->x.pSelect==0 );
           pOrig = pEList->a[j].pExpr;
-          if( !pNC->allowAgg && ExprHasProperty(pOrig, EP_Agg) ){
+          if( (pNC->ncFlags&NC_AllowAgg)==0 && ExprHasProperty(pOrig, EP_Agg) ){
             sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
-            sqlite3DbFree(db, zCol);
-            return 2;
+            return WRC_Abort;
           }
-          resolveAlias(pParse, pEList, j, pExpr, "");
+          resolveAlias(pParse, pEList, j, pExpr, "", nSubquery);
           cnt = 1;
           pMatch = 0;
           assert( zTab==0 && zDb==0 );
-          goto lookupname_end_2;
+          goto lookupname_end;
         }
       } 
     }
@@ -55382,6 +72323,7 @@ static int lookupName(
     */
     if( cnt==0 ){
       pNC = pNC->pNext;
+      nSubquery++;
     }
   }
 
@@ -55395,11 +72337,10 @@ static int lookupName(
   ** Because no reference was made to outer contexts, the pNC->nRef
   ** fields are not changed in any context.
   */
-  if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
-    sqlite3DbFree(db, zCol);
+  if( cnt==0 && zTab==0 && ExprHasProperty(pExpr,EP_DblQuoted) ){
     pExpr->op = TK_STRING;
     pExpr->pTab = 0;
-    return 0;
+    return WRC_Prune;
   }
 
   /*
@@ -55416,6 +72357,7 @@ static int lookupName(
     }else{
       sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
     }
+    pParse->checkSchema = 1;
     pTopNC->nErr++;
   }
 
@@ -55435,18 +72377,14 @@ static int lookupName(
     pMatch->colUsed |= ((Bitmask)1)<<n;
   }
 
-lookupname_end:
   /* Clean up and return
   */
-  sqlite3DbFree(db, zDb);
-  sqlite3DbFree(db, zTab);
   sqlite3ExprDelete(db, pExpr->pLeft);
   pExpr->pLeft = 0;
   sqlite3ExprDelete(db, pExpr->pRight);
   pExpr->pRight = 0;
-  pExpr->op = TK_COLUMN;
-lookupname_end_2:
-  sqlite3DbFree(db, zCol);
+  pExpr->op = (isTrigger ? TK_TRIGGER : TK_COLUMN);
+lookupname_end:
   if( cnt==1 ){
     assert( pNC!=0 );
     sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
@@ -55458,12 +72396,35 @@ lookupname_end_2:
       if( pTopNC==pNC ) break;
       pTopNC = pTopNC->pNext;
     }
-    return 0;
+    return WRC_Prune;
   } else {
-    return 1;
+    return WRC_Abort;
   }
 }
 
+/*
+** Allocate and return a pointer to an expression to load the column iCol
+** from datasource iSrc in SrcList pSrc.
+*/
+SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *db, SrcList *pSrc, int iSrc, int iCol){
+  Expr *p = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
+  if( p ){
+    struct SrcList_item *pItem = &pSrc->a[iSrc];
+    p->pTab = pItem->pTab;
+    p->iTable = pItem->iCursor;
+    if( p->pTab->iPKey==iCol ){
+      p->iColumn = -1;
+    }else{
+      p->iColumn = (ynVar)iCol;
+      testcase( iCol==BMS );
+      testcase( iCol==BMS-1 );
+      pItem->colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
+    }
+    ExprSetProperty(p, EP_Resolved);
+  }
+  return p;
+}
+
 /*
 ** This routine is callback for sqlite3WalkExpr().
 **
@@ -55519,41 +72480,39 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
     /* A lone identifier is the name of a column.
     */
     case TK_ID: {
-      lookupName(pParse, 0, 0, &pExpr->token, pNC, pExpr);
-      return WRC_Prune;
+      return lookupName(pParse, 0, 0, pExpr->u.zToken, pNC, pExpr);
     }
   
     /* A table name and column name:     ID.ID
     ** Or a database, table and column:  ID.ID.ID
     */
     case TK_DOT: {
-      Token *pColumn;
-      Token *pTable;
-      Token *pDb;
+      const char *zColumn;
+      const char *zTable;
+      const char *zDb;
       Expr *pRight;
 
       /* if( pSrcList==0 ) break; */
       pRight = pExpr->pRight;
       if( pRight->op==TK_ID ){
-        pDb = 0;
-        pTable = &pExpr->pLeft->token;
-        pColumn = &pRight->token;
+        zDb = 0;
+        zTable = pExpr->pLeft->u.zToken;
+        zColumn = pRight->u.zToken;
       }else{
         assert( pRight->op==TK_DOT );
-        pDb = &pExpr->pLeft->token;
-        pTable = &pRight->pLeft->token;
-        pColumn = &pRight->pRight->token;
+        zDb = pExpr->pLeft->u.zToken;
+        zTable = pRight->pLeft->u.zToken;
+        zColumn = pRight->pRight->u.zToken;
       }
-      lookupName(pParse, pDb, pTable, pColumn, pNC, pExpr);
-      return WRC_Prune;
+      return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
     }
 
     /* Resolve function names
     */
     case TK_CONST_FUNC:
     case TK_FUNCTION: {
-      ExprList *pList = pExpr->pList;    /* The argument list */
-      int n = pList ? pList->nExpr : 0;  /* Number of arguments */
+      ExprList *pList = pExpr->x.pList;    /* The argument list */
+      int n = pList ? pList->nExpr : 0;    /* Number of arguments */
       int no_such_func = 0;       /* True if no such function exists */
       int wrong_num_args = 0;     /* True if wrong number of arguments */
       int is_agg = 0;             /* True if is an aggregate function */
@@ -55563,11 +72522,13 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
       FuncDef *pDef;              /* Information about the function */
       u8 enc = ENC(pParse->db);   /* The database encoding */
 
-      zId = (char*)pExpr->token.z;
-      nId = pExpr->token.n;
+      testcase( pExpr->op==TK_CONST_FUNC );
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+      zId = pExpr->u.zToken;
+      nId = sqlite3Strlen30(zId);
       pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
       if( pDef==0 ){
-        pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
+        pDef = sqlite3FindFunction(pParse->db, zId, nId, -2, enc, 0);
         if( pDef==0 ){
           no_such_func = 1;
         }else{
@@ -55590,7 +72551,7 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
         }
       }
 #endif
-      if( is_agg && !pNC->allowAgg ){
+      if( is_agg && (pNC->ncFlags & NC_AllowAgg)==0 ){
         sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
         pNC->nErr++;
         is_agg = 0;
@@ -55602,13 +72563,19 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
              nId, zId);
         pNC->nErr++;
       }
-      if( is_agg ){
-        pExpr->op = TK_AGG_FUNCTION;
-        pNC->hasAgg = 1;
-      }
-      if( is_agg ) pNC->allowAgg = 0;
+      if( is_agg ) pNC->ncFlags &= ~NC_AllowAgg;
       sqlite3WalkExprList(pWalker, pList);
-      if( is_agg ) pNC->allowAgg = 1;
+      if( is_agg ){
+        NameContext *pNC2 = pNC;
+        pExpr->op = TK_AGG_FUNCTION;
+        pExpr->op2 = 0;
+        while( pNC2 && !sqlite3FunctionUsesThisSrc(pExpr, pNC2->pSrcList) ){
+          pExpr->op2++;
+          pNC2 = pNC2->pNext;
+        }
+        if( pNC2 ) pNC2->ncFlags |= NC_HasAgg;
+        pNC->ncFlags |= NC_AllowAgg;
+      }
       /* FIX ME:  Compute pExpr->affinity based on the expected return
       ** type of the function 
       */
@@ -55616,17 +72583,18 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
     }
 #ifndef SQLITE_OMIT_SUBQUERY
     case TK_SELECT:
-    case TK_EXISTS:
+    case TK_EXISTS:  testcase( pExpr->op==TK_EXISTS );
 #endif
     case TK_IN: {
-      if( pExpr->pSelect ){
+      testcase( pExpr->op==TK_IN );
+      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
         int nRef = pNC->nRef;
 #ifndef SQLITE_OMIT_CHECK
-        if( pNC->isCheck ){
+        if( (pNC->ncFlags & NC_IsCheck)!=0 ){
           sqlite3ErrorMsg(pParse,"subqueries prohibited in CHECK constraints");
         }
 #endif
-        sqlite3WalkSelect(pWalker, pExpr->pSelect);
+        sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
         assert( pNC->nRef>=nRef );
         if( nRef!=pNC->nRef ){
           ExprSetProperty(pExpr, EP_VarSelect);
@@ -55636,7 +72604,7 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){
     }
 #ifndef SQLITE_OMIT_CHECK
     case TK_VARIABLE: {
-      if( pNC->isCheck ){
+      if( (pNC->ncFlags & NC_IsCheck)!=0 ){
         sqlite3ErrorMsg(pParse,"parameters prohibited in CHECK constraints");
       }
       break;
@@ -55665,20 +72633,16 @@ static int resolveAsName(
 ){
   int i;             /* Loop counter */
 
-  if( pE->op==TK_ID || (pE->op==TK_STRING && pE->token.z[0]!='\'') ){
-    sqlite3 *db = pParse->db;
-    char *zCol = sqlite3NameFromToken(db, &pE->token);
-    if( zCol==0 ){
-      return -1;
-    }
+  UNUSED_PARAMETER(pParse);
+
+  if( pE->op==TK_ID ){
+    char *zCol = pE->u.zToken;
     for(i=0; i<pEList->nExpr; i++){
       char *zAs = pEList->a[i].zName;
       if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
-        sqlite3DbFree(db, zCol);
         return i+1;
       }
     }
-    sqlite3DbFree(db, zCol);
   }
   return 0;
 }
@@ -55709,6 +72673,9 @@ static int resolveOrderByTermToExprList(
   int i;             /* Loop counter */
   ExprList *pEList;  /* The columns of the result set */
   NameContext nc;    /* Name context for resolving pE */
+  sqlite3 *db;       /* Database connection */
+  int rc;            /* Return code from subprocedures */
+  u8 savedSuppErr;   /* Saved value of db->suppressErr */
 
   assert( sqlite3ExprIsInteger(pE, &i)==0 );
   pEList = pSelect->pEList;
@@ -55719,19 +72686,21 @@ static int resolveOrderByTermToExprList(
   nc.pParse = pParse;
   nc.pSrcList = pSelect->pSrc;
   nc.pEList = pEList;
-  nc.allowAgg = 1;
+  nc.ncFlags = NC_AllowAgg;
   nc.nErr = 0;
-  if( sqlite3ResolveExprNames(&nc, pE) ){
-    sqlite3ErrorClear(pParse);
-    return 0;
-  }
+  db = pParse->db;
+  savedSuppErr = db->suppressErr;
+  db->suppressErr = 1;
+  rc = sqlite3ResolveExprNames(&nc, pE);
+  db->suppressErr = savedSuppErr;
+  if( rc ) return 0;
 
   /* Try to match the ORDER BY expression against an expression
   ** in the result set.  Return an 1-based index of the matching
   ** result-set entry.
   */
   for(i=0; i<pEList->nExpr; i++){
-    if( sqlite3ExprCompare(pEList->a[i].pExpr, pE) ){
+    if( sqlite3ExprCompare(pEList->a[i].pExpr, pE)<2 ){
       return i+1;
     }
   }
@@ -55807,34 +72776,31 @@ static int resolveCompoundOrderBy(
       if( pItem->done ) continue;
       pE = pItem->pExpr;
       if( sqlite3ExprIsInteger(pE, &iCol) ){
-        if( iCol<0 || iCol>pEList->nExpr ){
+        if( iCol<=0 || iCol>pEList->nExpr ){
           resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr);
           return 1;
         }
       }else{
         iCol = resolveAsName(pParse, pEList, pE);
         if( iCol==0 ){
-          pDup = sqlite3ExprDup(db, pE);
+          pDup = sqlite3ExprDup(db, pE, 0);
           if( !db->mallocFailed ){
             assert(pDup);
             iCol = resolveOrderByTermToExprList(pParse, pSelect, pDup);
           }
           sqlite3ExprDelete(db, pDup);
         }
-        if( iCol<0 ){
-          return 1;
-        }
       }
       if( iCol>0 ){
         CollSeq *pColl = pE->pColl;
         int flags = pE->flags & EP_ExpCollate;
         sqlite3ExprDelete(db, pE);
-        pItem->pExpr = pE = sqlite3Expr(db, TK_INTEGER, 0, 0, 0);
+        pItem->pExpr = pE = sqlite3Expr(db, TK_INTEGER, 0);
         if( pE==0 ) return 1;
         pE->pColl = pColl;
         pE->flags |= EP_IntValue | flags;
-        pE->iTable = iCol;
-        pItem->iCol = (u16)iCol;
+        pE->u.iValue = iCol;
+        pItem->iOrderByCol = (u16)iCol;
         pItem->done = 1;
       }else{
         moreToDo = 1;
@@ -55883,12 +72849,12 @@ SQLITE_PRIVATE int sqlite3ResolveOrderGroupBy(
   pEList = pSelect->pEList;
   assert( pEList!=0 );  /* sqlite3SelectNew() guarantees this */
   for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
-    if( pItem->iCol ){
-      if( pItem->iCol>pEList->nExpr ){
+    if( pItem->iOrderByCol ){
+      if( pItem->iOrderByCol>pEList->nExpr ){
         resolveOutOfRangeError(pParse, zType, i+1, pEList->nExpr);
         return 1;
       }
-      resolveAlias(pParse, pEList, pItem->iCol-1, pItem->pExpr, zType);
+      resolveAlias(pParse, pEList, pItem->iOrderByCol-1, pItem->pExpr, zType,0);
     }
   }
   return 0;
@@ -55918,7 +72884,7 @@ static int resolveOrderGroupBy(
   ExprList *pOrderBy,   /* An ORDER BY or GROUP BY clause to resolve */
   const char *zType     /* Either "ORDER" or "GROUP", as appropriate */
 ){
-  int i;                         /* Loop counter */
+  int i, j;                      /* Loop counters */
   int iCol;                      /* Column number */
   struct ExprList_item *pItem;   /* A term of the ORDER BY clause */
   Parse *pParse;                 /* Parsing context */
@@ -55930,15 +72896,12 @@ static int resolveOrderGroupBy(
   for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
     Expr *pE = pItem->pExpr;
     iCol = resolveAsName(pParse, pSelect->pEList, pE);
-    if( iCol<0 ){
-      return 1;  /* OOM error */
-    }
     if( iCol>0 ){
       /* If an AS-name match is found, mark this ORDER BY column as being
       ** a copy of the iCol-th result-set column.  The subsequent call to
       ** sqlite3ResolveOrderGroupBy() will convert the expression to a
       ** copy of the iCol-th result-set expression. */
-      pItem->iCol = (u16)iCol;
+      pItem->iOrderByCol = (u16)iCol;
       continue;
     }
     if( sqlite3ExprIsInteger(pE, &iCol) ){
@@ -55949,15 +72912,20 @@ static int resolveOrderGroupBy(
         resolveOutOfRangeError(pParse, zType, i+1, nResult);
         return 1;
       }
-      pItem->iCol = (u16)iCol;
+      pItem->iOrderByCol = (u16)iCol;
       continue;
     }
 
     /* Otherwise, treat the ORDER BY term as an ordinary expression */
-    pItem->iCol = 0;
+    pItem->iOrderByCol = 0;
     if( sqlite3ResolveExprNames(pNC, pE) ){
       return 1;
     }
+    for(j=0; j<pSelect->pEList->nExpr; j++){
+      if( sqlite3ExprCompare(pE, pSelect->pEList->a[j].pExpr)==0 ){
+        pItem->iOrderByCol = j+1;
+      }
+    }
   }
   return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType);
 }
@@ -56020,7 +72988,7 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     /* Set up the local name-context to pass to sqlite3ResolveExprNames() to
     ** resolve the result-set expression list.
     */
-    sNC.allowAgg = 1;
+    sNC.ncFlags = NC_AllowAgg;
     sNC.pSrcList = p->pSrc;
     sNC.pNext = pOuterNC;
   
@@ -56039,11 +73007,25 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     for(i=0; i<p->pSrc->nSrc; i++){
       struct SrcList_item *pItem = &p->pSrc->a[i];
       if( pItem->pSelect ){
+        NameContext *pNC;         /* Used to iterate name contexts */
+        int nRef = 0;             /* Refcount for pOuterNC and outer contexts */
         const char *zSavedContext = pParse->zAuthContext;
+
+        /* Count the total number of references to pOuterNC and all of its
+        ** parent contexts. After resolving references to expressions in
+        ** pItem->pSelect, check if this value has changed. If so, then
+        ** SELECT statement pItem->pSelect must be correlated. Set the
+        ** pItem->isCorrelated flag if this is the case. */
+        for(pNC=pOuterNC; pNC; pNC=pNC->pNext) nRef += pNC->nRef;
+
         if( pItem->zName ) pParse->zAuthContext = pItem->zName;
         sqlite3ResolveSelectNames(pParse, pItem->pSelect, pOuterNC);
         pParse->zAuthContext = zSavedContext;
         if( pParse->nErr || db->mallocFailed ) return WRC_Abort;
+
+        for(pNC=pOuterNC; pNC; pNC=pNC->pNext) nRef -= pNC->nRef;
+        assert( pItem->isCorrelated==0 && nRef<=0 );
+        pItem->isCorrelated = (nRef!=0);
       }
     }
   
@@ -56052,10 +73034,10 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     */
     assert( (p->selFlags & SF_Aggregate)==0 );
     pGroupBy = p->pGroupBy;
-    if( pGroupBy || sNC.hasAgg ){
+    if( pGroupBy || (sNC.ncFlags & NC_HasAgg)!=0 ){
       p->selFlags |= SF_Aggregate;
     }else{
-      sNC.allowAgg = 0;
+      sNC.ncFlags &= ~NC_AllowAgg;
     }
   
     /* If a HAVING clause is present, then there must be a GROUP BY clause.
@@ -56084,7 +73066,7 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
     ** outer queries 
     */
     sNC.pNext = 0;
-    sNC.allowAgg = 1;
+    sNC.ncFlags |= NC_AllowAgg;
 
     /* Process the ORDER BY clause for singleton SELECT statements.
     ** The ORDER BY clause for compounds SELECT statements is handled
@@ -56172,7 +73154,7 @@ static int resolveSelectStep(Walker *pWalker, Select *p){
 **
 ** Function calls are checked to make sure that the function is 
 ** defined and that the correct number of arguments are specified.
-** If the function is an aggregate function, then the pNC->hasAgg is
+** If the function is an aggregate function, then the NC_HasAgg flag is
 ** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
 ** If an expression contains aggregate functions then the EP_Agg
 ** property on the expression is set.
@@ -56184,7 +73166,7 @@ SQLITE_PRIVATE int sqlite3ResolveExprNames(
   NameContext *pNC,       /* Namespace to resolve expressions in. */
   Expr *pExpr             /* The expression to be analyzed. */
 ){
-  int savedHasAgg;
+  u8 savedHasAgg;
   Walker w;
 
   if( pExpr==0 ) return 0;
@@ -56197,8 +73179,8 @@ SQLITE_PRIVATE int sqlite3ResolveExprNames(
     pParse->nHeight += pExpr->nHeight;
   }
 #endif
-  savedHasAgg = pNC->hasAgg;
-  pNC->hasAgg = 0;
+  savedHasAgg = pNC->ncFlags & NC_HasAgg;
+  pNC->ncFlags &= ~NC_HasAgg;
   w.xExprCallback = resolveExprStep;
   w.xSelectCallback = resolveSelectStep;
   w.pParse = pNC->pParse;
@@ -56207,13 +73189,13 @@ SQLITE_PRIVATE int sqlite3ResolveExprNames(
 #if SQLITE_MAX_EXPR_DEPTH>0
   pNC->pParse->nHeight -= pExpr->nHeight;
 #endif
-  if( pNC->nErr>0 ){
+  if( pNC->nErr>0 || w.pParse->nErr>0 ){
     ExprSetProperty(pExpr, EP_Error);
   }
-  if( pNC->hasAgg ){
+  if( pNC->ncFlags & NC_HasAgg ){
     ExprSetProperty(pExpr, EP_Agg);
   }else if( savedHasAgg ){
-    pNC->hasAgg = 1;
+    pNC->ncFlags |= NC_HasAgg;
   }
   return ExprHasProperty(pExpr, EP_Error);
 }
@@ -56261,8 +73243,6 @@ SQLITE_PRIVATE void sqlite3ResolveSelectNames(
 *************************************************************************
 ** This file contains routines used for analyzing expressions and
 ** for generating VDBE code that evaluates expressions in SQLite.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -56284,11 +73264,13 @@ SQLITE_PRIVATE void sqlite3ResolveSelectNames(
 SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr){
   int op = pExpr->op;
   if( op==TK_SELECT ){
-    return sqlite3ExprAffinity(pExpr->pSelect->pEList->a[0].pExpr);
+    assert( pExpr->flags&EP_xIsSelect );
+    return sqlite3ExprAffinity(pExpr->x.pSelect->pEList->a[0].pExpr);
   }
 #ifndef SQLITE_OMIT_CAST
   if( op==TK_CAST ){
-    return sqlite3AffinityType(&pExpr->token);
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    return sqlite3AffinityType(pExpr->u.zToken);
   }
 #endif
   if( (op==TK_AGG_COLUMN || op==TK_COLUMN || op==TK_REGISTER) 
@@ -56304,6 +73286,18 @@ SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr){
   return pExpr->affinity;
 }
 
+/*
+** Set the explicit collating sequence for an expression to the
+** collating sequence supplied in the second argument.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSetColl(Expr *pExpr, CollSeq *pColl){
+  if( pExpr && pColl ){
+    pExpr->pColl = pColl;
+    pExpr->flags |= EP_ExpCollate;
+  }
+  return pExpr;
+}
+
 /*
 ** Set the collating sequence for expression pExpr to be the collating
 ** sequence named by pToken.   Return a pointer to the revised expression.
@@ -56311,18 +73305,13 @@ SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr){
 ** flag.  An explicit collating sequence will override implicit
 ** collating sequences.
 */
-SQLITE_PRIVATE Expr *sqlite3ExprSetColl(Parse *pParse, Expr *pExpr, Token *pCollName){
+SQLITE_PRIVATE Expr *sqlite3ExprSetCollByToken(Parse *pParse, Expr *pExpr, Token *pCollName){
   char *zColl = 0;            /* Dequoted name of collation sequence */
   CollSeq *pColl;
   sqlite3 *db = pParse->db;
   zColl = sqlite3NameFromToken(db, pCollName);
-  if( pExpr && zColl ){
-    pColl = sqlite3LocateCollSeq(pParse, zColl, -1);
-    if( pColl ){
-      pExpr->pColl = pColl;
-      pExpr->flags |= EP_ExpCollate;
-    }
-  }
+  pColl = sqlite3LocateCollSeq(pParse, zColl);
+  sqlite3ExprSetColl(pExpr, pColl);
   sqlite3DbFree(db, zColl);
   return pExpr;
 }
@@ -56339,7 +73328,9 @@ SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
     pColl = p->pColl;
     if( pColl ) break;
     op = p->op;
-    if( (op==TK_AGG_COLUMN || op==TK_COLUMN || op==TK_REGISTER) && p->pTab!=0 ){
+    if( p->pTab!=0 && (
+        op==TK_AGG_COLUMN || op==TK_COLUMN || op==TK_REGISTER || op==TK_TRIGGER
+    )){
       /* op==TK_REGISTER && p->pTab!=0 happens when pExpr was originally
       ** a TK_COLUMN but was previously evaluated and cached in a register */
       const char *zColl;
@@ -56347,7 +73338,7 @@ SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
       if( j>=0 ){
         sqlite3 *db = pParse->db;
         zColl = p->pTab->aCol[j].zColl;
-        pColl = sqlite3FindCollSeq(db, ENC(db), zColl, -1, 0);
+        pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
         pExpr->pColl = pColl;
       }
       break;
@@ -56399,16 +73390,14 @@ static char comparisonAffinity(Expr *pExpr){
   char aff;
   assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
           pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
-          pExpr->op==TK_NE );
+          pExpr->op==TK_NE || pExpr->op==TK_IS || pExpr->op==TK_ISNOT );
   assert( pExpr->pLeft );
   aff = sqlite3ExprAffinity(pExpr->pLeft);
   if( pExpr->pRight ){
     aff = sqlite3CompareAffinity(pExpr->pRight, aff);
-  }
-  else if( pExpr->pSelect ){
-    aff = sqlite3CompareAffinity(pExpr->pSelect->pEList->a[0].pExpr, aff);
-  }
-  else if( !aff ){
+  }else if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+    aff = sqlite3CompareAffinity(pExpr->x.pSelect->pEList->a[0].pExpr, aff);
+  }else if( !aff ){
     aff = SQLITE_AFF_NONE;
   }
   return aff;
@@ -56476,30 +73465,6 @@ SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(
   return pColl;
 }
 
-/*
-** Generate the operands for a comparison operation.  Before
-** generating the code for each operand, set the EP_AnyAff
-** flag on the expression so that it will be able to used a
-** cached column value that has previously undergone an
-** affinity change.
-*/
-static void codeCompareOperands(
-  Parse *pParse,    /* Parsing and code generating context */
-  Expr *pLeft,      /* The left operand */
-  int *pRegLeft,    /* Register where left operand is stored */
-  int *pFreeLeft,   /* Free this register when done */
-  Expr *pRight,     /* The right operand */
-  int *pRegRight,   /* Register where right operand is stored */
-  int *pFreeRight   /* Write temp register for right operand there */
-){
-  while( pLeft->op==TK_UPLUS ) pLeft = pLeft->pLeft;
-  pLeft->flags |= EP_AnyAff;
-  *pRegLeft = sqlite3ExprCodeTemp(pParse, pLeft, pFreeLeft);
-  while( pRight->op==TK_UPLUS ) pRight = pRight->pLeft;
-  pRight->flags |= EP_AnyAff;
-  *pRegRight = sqlite3ExprCodeTemp(pParse, pRight, pFreeRight);
-}
-
 /*
 ** Generate code for a comparison operator.
 */
@@ -56521,10 +73486,6 @@ static int codeCompare(
   addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
                            (void*)p4, P4_COLLSEQ);
   sqlite3VdbeChangeP5(pParse->pVdbe, (u8)p5);
-  if( (p5 & SQLITE_AFF_MASK)!=SQLITE_AFF_NONE ){
-    sqlite3ExprCacheAffinityChange(pParse, in1, 1);
-    sqlite3ExprCacheAffinityChange(pParse, in2, 1);
-  }
   return addr;
 }
 
@@ -56594,8 +73555,11 @@ static void exprSetHeight(Expr *p){
   int nHeight = 0;
   heightOfExpr(p->pLeft, &nHeight);
   heightOfExpr(p->pRight, &nHeight);
-  heightOfExprList(p->pList, &nHeight);
-  heightOfSelect(p->pSelect, &nHeight);
+  if( ExprHasProperty(p, EP_xIsSelect) ){
+    heightOfSelect(p->x.pSelect, &nHeight);
+  }else{
+    heightOfExprList(p->x.pList, &nHeight);
+  }
   p->nHeight = nHeight + 1;
 }
 
@@ -56623,59 +73587,126 @@ SQLITE_PRIVATE int sqlite3SelectExprHeight(Select *p){
 #endif /* SQLITE_MAX_EXPR_DEPTH>0 */
 
 /*
+** This routine is the core allocator for Expr nodes.
+**
 ** Construct a new expression node and return a pointer to it.  Memory
-** for this node is obtained from sqlite3_malloc().  The calling function
+** for this node and for the pToken argument is a single allocation
+** obtained from sqlite3DbMalloc().  The calling function
 ** is responsible for making sure the node eventually gets freed.
+**
+** If dequote is true, then the token (if it exists) is dequoted.
+** If dequote is false, no dequoting is performance.  The deQuote
+** parameter is ignored if pToken is NULL or if the token does not
+** appear to be quoted.  If the quotes were of the form "..." (double-quotes)
+** then the EP_DblQuoted flag is set on the expression node.
+**
+** Special case:  If op==TK_INTEGER and pToken points to a string that
+** can be translated into a 32-bit integer, then the token is not
+** stored in u.zToken.  Instead, the integer values is written
+** into u.iValue and the EP_IntValue flag is set.  No extra storage
+** is allocated to hold the integer text and the dequote flag is ignored.
 */
-SQLITE_PRIVATE Expr *sqlite3Expr(
+SQLITE_PRIVATE Expr *sqlite3ExprAlloc(
   sqlite3 *db,            /* Handle for sqlite3DbMallocZero() (may be null) */
   int op,                 /* Expression opcode */
-  Expr *pLeft,            /* Left operand */
-  Expr *pRight,           /* Right operand */
-  const Token *pToken     /* Argument token */
+  const Token *pToken,    /* Token argument.  Might be NULL */
+  int dequote             /* True to dequote */
 ){
   Expr *pNew;
-  pNew = sqlite3DbMallocZero(db, sizeof(Expr));
-  if( pNew==0 ){
-    /* When malloc fails, delete pLeft and pRight. Expressions passed to 
-    ** this function must always be allocated with sqlite3Expr() for this 
-    ** reason. 
-    */
-    sqlite3ExprDelete(db, pLeft);
-    sqlite3ExprDelete(db, pRight);
-    return 0;
-  }
-  pNew->op = (u8)op;
-  pNew->pLeft = pLeft;
-  pNew->pRight = pRight;
-  pNew->iAgg = -1;
-  pNew->span.z = (u8*)"";
-  if( pToken ){
-    assert( pToken->dyn==0 );
-    pNew->span = pNew->token = *pToken;
-  }else if( pLeft ){
-    if( pRight ){
-      if( pRight->span.dyn==0 && pLeft->span.dyn==0 ){
-        sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
-      }
-      if( pRight->flags & EP_ExpCollate ){
-        pNew->flags |= EP_ExpCollate;
-        pNew->pColl = pRight->pColl;
-      }
-    }
-    if( pLeft->flags & EP_ExpCollate ){
-      pNew->flags |= EP_ExpCollate;
-      pNew->pColl = pLeft->pColl;
-    }
-  }
+  int nExtra = 0;
+  int iValue = 0;
 
-  exprSetHeight(pNew);
+  if( pToken ){
+    if( op!=TK_INTEGER || pToken->z==0
+          || sqlite3GetInt32(pToken->z, &iValue)==0 ){
+      nExtra = pToken->n+1;
+      assert( iValue>=0 );
+    }
+  }
+  pNew = sqlite3DbMallocZero(db, sizeof(Expr)+nExtra);
+  if( pNew ){
+    pNew->op = (u8)op;
+    pNew->iAgg = -1;
+    if( pToken ){
+      if( nExtra==0 ){
+        pNew->flags |= EP_IntValue;
+        pNew->u.iValue = iValue;
+      }else{
+        int c;
+        pNew->u.zToken = (char*)&pNew[1];
+        assert( pToken->z!=0 || pToken->n==0 );
+        if( pToken->n ) memcpy(pNew->u.zToken, pToken->z, pToken->n);
+        pNew->u.zToken[pToken->n] = 0;
+        if( dequote && nExtra>=3 
+             && ((c = pToken->z[0])=='\'' || c=='"' || c=='[' || c=='`') ){
+          sqlite3Dequote(pNew->u.zToken);
+          if( c=='"' ) pNew->flags |= EP_DblQuoted;
+        }
+      }
+    }
+#if SQLITE_MAX_EXPR_DEPTH>0
+    pNew->nHeight = 1;
+#endif  
+  }
   return pNew;
 }
 
 /*
-** Works like sqlite3Expr() except that it takes an extra Parse*
-** argument and notifies the associated connection object if malloc fails.
+** Allocate a new expression node from a zero-terminated token that has
+** already been dequoted.
+*/
+SQLITE_PRIVATE Expr *sqlite3Expr(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocZero() (may be null) */
+  int op,                 /* Expression opcode */
+  const char *zToken      /* Token argument.  Might be NULL */
+){
+  Token x;
+  x.z = zToken;
+  x.n = zToken ? sqlite3Strlen30(zToken) : 0;
+  return sqlite3ExprAlloc(db, op, &x, 0);
+}
+
+/*
+** Attach subtrees pLeft and pRight to the Expr node pRoot.
+**
+** If pRoot==NULL that means that a memory allocation error has occurred.
+** In that case, delete the subtrees pLeft and pRight.
+*/
+SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(
+  sqlite3 *db,
+  Expr *pRoot,
+  Expr *pLeft,
+  Expr *pRight
+){
+  if( pRoot==0 ){
+    assert( db->mallocFailed );
+    sqlite3ExprDelete(db, pLeft);
+    sqlite3ExprDelete(db, pRight);
+  }else{
+    if( pRight ){
+      pRoot->pRight = pRight;
+      if( pRight->flags & EP_ExpCollate ){
+        pRoot->flags |= EP_ExpCollate;
+        pRoot->pColl = pRight->pColl;
+      }
+    }
+    if( pLeft ){
+      pRoot->pLeft = pLeft;
+      if( pLeft->flags & EP_ExpCollate ){
+        pRoot->flags |= EP_ExpCollate;
+        pRoot->pColl = pLeft->pColl;
+      }
+    }
+    exprSetHeight(pRoot);
+  }
+}
+
+/*
+** Allocate a Expr node which joins as many as two subtrees.
+**
+** One or both of the subtrees can be NULL.  Return a pointer to the new
+** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
+** free the subtrees and return NULL.
 */
 SQLITE_PRIVATE Expr *sqlite3PExpr(
   Parse *pParse,          /* Parsing context */
@@ -56684,64 +73715,59 @@ SQLITE_PRIVATE Expr *sqlite3PExpr(
   Expr *pRight,           /* Right operand */
   const Token *pToken     /* Argument token */
 ){
-  Expr *p = sqlite3Expr(pParse->db, op, pLeft, pRight, pToken);
-  if( p ){
+  Expr *p;
+  if( op==TK_AND && pLeft && pRight ){
+    /* Take advantage of short-circuit false optimization for AND */
+    p = sqlite3ExprAnd(pParse->db, pLeft, pRight);
+  }else{
+    p = sqlite3ExprAlloc(pParse->db, op, pToken, 1);
+    sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
+  }
+  if( p ) {
     sqlite3ExprCheckHeight(pParse, p->nHeight);
   }
   return p;
 }
 
 /*
-** When doing a nested parse, you can include terms in an expression
-** that look like this:   #1 #2 ...  These terms refer to registers
-** in the virtual machine.  #N is the N-th register.
+** Return 1 if an expression must be FALSE in all cases and 0 if the
+** expression might be true.  This is an optimization.  If is OK to
+** return 0 here even if the expression really is always false (a 
+** false negative).  But it is a bug to return 1 if the expression
+** might be true in some rare circumstances (a false positive.)
 **
-** This routine is called by the parser to deal with on of those terms.
-** It immediately generates code to store the value in a memory location.
-** The returns an expression that will code to extract the value from
-** that memory location as needed.
+** Note that if the expression is part of conditional for a
+** LEFT JOIN, then we cannot determine at compile-time whether or not
+** is it true or false, so always return 0.
 */
-SQLITE_PRIVATE Expr *sqlite3RegisterExpr(Parse *pParse, Token *pToken){
-  Vdbe *v = pParse->pVdbe;
-  Expr *p;
-  if( pParse->nested==0 ){
-    sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", pToken);
-    return sqlite3PExpr(pParse, TK_NULL, 0, 0, 0);
-  }
-  if( v==0 ) return 0;
-  p = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, pToken);
-  if( p==0 ){
-    return 0;  /* Malloc failed */
-  }
-  p->iTable = atoi((char*)&pToken->z[1]);
-  return p;
+static int exprAlwaysFalse(Expr *p){
+  int v = 0;
+  if( ExprHasProperty(p, EP_FromJoin) ) return 0;
+  if( !sqlite3ExprIsInteger(p, &v) ) return 0;
+  return v==0;
 }
 
 /*
 ** Join two expressions using an AND operator.  If either expression is
 ** NULL, then just return the other expression.
+**
+** If one side or the other of the AND is known to be false, then instead
+** of returning an AND expression, just return a constant expression with
+** a value of false.
 */
 SQLITE_PRIVATE Expr *sqlite3ExprAnd(sqlite3 *db, Expr *pLeft, Expr *pRight){
   if( pLeft==0 ){
     return pRight;
   }else if( pRight==0 ){
     return pLeft;
+  }else if( exprAlwaysFalse(pLeft) || exprAlwaysFalse(pRight) ){
+    sqlite3ExprDelete(db, pLeft);
+    sqlite3ExprDelete(db, pRight);
+    return sqlite3ExprAlloc(db, TK_INTEGER, &sqlite3IntTokens[0], 0);
   }else{
-    return sqlite3Expr(db, TK_AND, pLeft, pRight, 0);
-  }
-}
-
-/*
-** Set the Expr.span field of the given expression to span all
-** text between the two given tokens.  Both tokens must be pointing
-** at the same string.
-*/
-SQLITE_PRIVATE void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
-  assert( pRight!=0 );
-  assert( pLeft!=0 );
-  if( pExpr ){
-    pExpr->span.z = pLeft->z;
-    pExpr->span.n = pRight->n + (pRight->z - pLeft->z);
+    Expr *pNew = sqlite3ExprAlloc(db, TK_AND, 0, 0);
+    sqlite3ExprAttachSubtrees(db, pNew, pLeft, pRight);
+    return pNew;
   }
 }
 
@@ -56753,17 +73779,13 @@ SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse *pParse, ExprList *pList, Token *
   Expr *pNew;
   sqlite3 *db = pParse->db;
   assert( pToken );
-  pNew = sqlite3DbMallocZero(db, sizeof(Expr) );
+  pNew = sqlite3ExprAlloc(db, TK_FUNCTION, pToken, 1);
   if( pNew==0 ){
-    sqlite3ExprListDelete(db, pList); /* Avoid leaking memory when malloc fails */
+    sqlite3ExprListDelete(db, pList); /* Avoid memory leak when malloc fails */
     return 0;
   }
-  pNew->op = TK_FUNCTION;
-  pNew->pList = pList;
-  assert( pToken->dyn==0 );
-  pNew->token = *pToken;
-  pNew->span = pNew->token;
-
+  pNew->x.pList = pList;
+  assert( !ExprHasProperty(pNew, EP_xIsSelect) );
   sqlite3ExprSetHeight(pParse, pNew);
   return pNew;
 }
@@ -56779,70 +73801,71 @@ SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse *pParse, ExprList *pList, Token *
 ** sure "nnn" is not too be to avoid a denial of service attack when
 ** the SQL statement comes from an external source.
 **
-** Wildcards of the form ":aaa" or "$aaa" are assigned the same number
+** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
 ** as the previous instance of the same wildcard.  Or if this is the first
 ** instance of the wildcard, the next sequenial variable number is
 ** assigned.
 */
 SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
-  Token *pToken;
   sqlite3 *db = pParse->db;
+  const char *z;
 
   if( pExpr==0 ) return;
-  pToken = &pExpr->token;
-  assert( pToken->n>=1 );
-  assert( pToken->z!=0 );
-  assert( pToken->z[0]!=0 );
-  if( pToken->n==1 ){
+  assert( !ExprHasAnyProperty(pExpr, EP_IntValue|EP_Reduced|EP_TokenOnly) );
+  z = pExpr->u.zToken;
+  assert( z!=0 );
+  assert( z[0]!=0 );
+  if( z[1]==0 ){
     /* Wildcard of the form "?".  Assign the next variable number */
-    pExpr->iTable = ++pParse->nVar;
-  }else if( pToken->z[0]=='?' ){
-    /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
-    ** use it as the variable number */
-    int i;
-    pExpr->iTable = i = atoi((char*)&pToken->z[1]);
-    testcase( i==0 );
-    testcase( i==1 );
-    testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
-    testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
-    if( i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
-      sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
-          db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
-    }
-    if( i>pParse->nVar ){
-      pParse->nVar = i;
-    }
+    assert( z[0]=='?' );
+    pExpr->iColumn = (ynVar)(++pParse->nVar);
   }else{
-    /* Wildcards of the form ":aaa" or "$aaa".  Reuse the same variable
-    ** number as the prior appearance of the same name, or if the name
-    ** has never appeared before, reuse the same variable number
-    */
-    int i;
-    u32 n;
-    n = pToken->n;
-    for(i=0; i<pParse->nVarExpr; i++){
-      Expr *pE;
-      if( (pE = pParse->apVarExpr[i])!=0
-          && pE->token.n==n
-          && memcmp(pE->token.z, pToken->z, n)==0 ){
-        pExpr->iTable = pE->iTable;
-        break;
+    ynVar x = 0;
+    u32 n = sqlite3Strlen30(z);
+    if( z[0]=='?' ){
+      /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
+      ** use it as the variable number */
+      i64 i;
+      int bOk = 0==sqlite3Atoi64(&z[1], &i, n-1, SQLITE_UTF8);
+      pExpr->iColumn = x = (ynVar)i;
+      testcase( i==0 );
+      testcase( i==1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
+      if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+        sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
+            db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
+        x = 0;
       }
+      if( i>pParse->nVar ){
+        pParse->nVar = (int)i;
+      }
+    }else{
+      /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
+      ** number as the prior appearance of the same name, or if the name
+      ** has never appeared before, reuse the same variable number
+      */
+      ynVar i;
+      for(i=0; i<pParse->nzVar; i++){
+        if( pParse->azVar[i] && memcmp(pParse->azVar[i],z,n+1)==0 ){
+          pExpr->iColumn = x = (ynVar)i+1;
+          break;
+        }
+      }
+      if( x==0 ) x = pExpr->iColumn = (ynVar)(++pParse->nVar);
     }
-    if( i>=pParse->nVarExpr ){
-      pExpr->iTable = ++pParse->nVar;
-      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
-        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
-        pParse->apVarExpr =
-            sqlite3DbReallocOrFree(
-              db,
-              pParse->apVarExpr,
-              pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0])
-            );
+    if( x>0 ){
+      if( x>pParse->nzVar ){
+        char **a;
+        a = sqlite3DbRealloc(db, pParse->azVar, x*sizeof(a[0]));
+        if( a==0 ) return;  /* Error reported through db->mallocFailed */
+        pParse->azVar = a;
+        memset(&a[pParse->nzVar], 0, (x-pParse->nzVar)*sizeof(a[0]));
+        pParse->nzVar = x;
       }
-      if( !db->mallocFailed ){
-        assert( pParse->apVarExpr!=0 );
-        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
+      if( z[0]!='?' || pParse->azVar[x-1]==0 ){
+        sqlite3DbFree(db, pParse->azVar[x-1]);
+        pParse->azVar[x-1] = sqlite3DbStrNDup(db, z, n);
       }
     }
   } 
@@ -56851,41 +73874,221 @@ SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
   }
 }
 
-/*
-** Clear an expression structure without deleting the structure itself.
-** Substructure is deleted.
-*/
-SQLITE_PRIVATE void sqlite3ExprClear(sqlite3 *db, Expr *p){
-  if( p->span.dyn ) sqlite3DbFree(db, (char*)p->span.z);
-  if( p->token.dyn ) sqlite3DbFree(db, (char*)p->token.z);
-  sqlite3ExprDelete(db, p->pLeft);
-  sqlite3ExprDelete(db, p->pRight);
-  sqlite3ExprListDelete(db, p->pList);
-  sqlite3SelectDelete(db, p->pSelect);
-}
-
 /*
 ** Recursively delete an expression tree.
 */
 SQLITE_PRIVATE void sqlite3ExprDelete(sqlite3 *db, Expr *p){
   if( p==0 ) return;
-  sqlite3ExprClear(db, p);
-  sqlite3DbFree(db, p);
+  /* Sanity check: Assert that the IntValue is non-negative if it exists */
+  assert( !ExprHasProperty(p, EP_IntValue) || p->u.iValue>=0 );
+  if( !ExprHasAnyProperty(p, EP_TokenOnly) ){
+    sqlite3ExprDelete(db, p->pLeft);
+    sqlite3ExprDelete(db, p->pRight);
+    if( !ExprHasProperty(p, EP_Reduced) && (p->flags2 & EP2_MallocedToken)!=0 ){
+      sqlite3DbFree(db, p->u.zToken);
+    }
+    if( ExprHasProperty(p, EP_xIsSelect) ){
+      sqlite3SelectDelete(db, p->x.pSelect);
+    }else{
+      sqlite3ExprListDelete(db, p->x.pList);
+    }
+  }
+  if( !ExprHasProperty(p, EP_Static) ){
+    sqlite3DbFree(db, p);
+  }
 }
 
 /*
-** The Expr.token field might be a string literal that is quoted.
-** If so, remove the quotation marks.
+** Return the number of bytes allocated for the expression structure 
+** passed as the first argument. This is always one of EXPR_FULLSIZE,
+** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
 */
-SQLITE_PRIVATE void sqlite3DequoteExpr(sqlite3 *db, Expr *p){
-  if( ExprHasAnyProperty(p, EP_Dequoted) ){
-    return;
+static int exprStructSize(Expr *p){
+  if( ExprHasProperty(p, EP_TokenOnly) ) return EXPR_TOKENONLYSIZE;
+  if( ExprHasProperty(p, EP_Reduced) ) return EXPR_REDUCEDSIZE;
+  return EXPR_FULLSIZE;
+}
+
+/*
+** The dupedExpr*Size() routines each return the number of bytes required
+** to store a copy of an expression or expression tree.  They differ in
+** how much of the tree is measured.
+**
+**     dupedExprStructSize()     Size of only the Expr structure 
+**     dupedExprNodeSize()       Size of Expr + space for token
+**     dupedExprSize()           Expr + token + subtree components
+**
+***************************************************************************
+**
+** The dupedExprStructSize() function returns two values OR-ed together:  
+** (1) the space required for a copy of the Expr structure only and 
+** (2) the EP_xxx flags that indicate what the structure size should be.
+** The return values is always one of:
+**
+**      EXPR_FULLSIZE
+**      EXPR_REDUCEDSIZE   | EP_Reduced
+**      EXPR_TOKENONLYSIZE | EP_TokenOnly
+**
+** The size of the structure can be found by masking the return value
+** of this routine with 0xfff.  The flags can be found by masking the
+** return value with EP_Reduced|EP_TokenOnly.
+**
+** Note that with flags==EXPRDUP_REDUCE, this routines works on full-size
+** (unreduced) Expr objects as they or originally constructed by the parser.
+** During expression analysis, extra information is computed and moved into
+** later parts of teh Expr object and that extra information might get chopped
+** off if the expression is reduced.  Note also that it does not work to
+** make a EXPRDUP_REDUCE copy of a reduced expression.  It is only legal
+** to reduce a pristine expression tree from the parser.  The implementation
+** of dupedExprStructSize() contain multiple assert() statements that attempt
+** to enforce this constraint.
+*/
+static int dupedExprStructSize(Expr *p, int flags){
+  int nSize;
+  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
+  if( 0==(flags&EXPRDUP_REDUCE) ){
+    nSize = EXPR_FULLSIZE;
+  }else{
+    assert( !ExprHasAnyProperty(p, EP_TokenOnly|EP_Reduced) );
+    assert( !ExprHasProperty(p, EP_FromJoin) ); 
+    assert( (p->flags2 & EP2_MallocedToken)==0 );
+    assert( (p->flags2 & EP2_Irreducible)==0 );
+    if( p->pLeft || p->pRight || p->pColl || p->x.pList ){
+      nSize = EXPR_REDUCEDSIZE | EP_Reduced;
+    }else{
+      nSize = EXPR_TOKENONLYSIZE | EP_TokenOnly;
+    }
   }
-  ExprSetProperty(p, EP_Dequoted);
-  if( p->token.dyn==0 ){
-    sqlite3TokenCopy(db, &p->token, &p->token);
+  return nSize;
+}
+
+/*
+** This function returns the space in bytes required to store the copy 
+** of the Expr structure and a copy of the Expr.u.zToken string (if that
+** string is defined.)
+*/
+static int dupedExprNodeSize(Expr *p, int flags){
+  int nByte = dupedExprStructSize(p, flags) & 0xfff;
+  if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+    nByte += sqlite3Strlen30(p->u.zToken)+1;
   }
-  sqlite3Dequote((char*)p->token.z);
+  return ROUND8(nByte);
+}
+
+/*
+** Return the number of bytes required to create a duplicate of the 
+** expression passed as the first argument. The second argument is a
+** mask containing EXPRDUP_XXX flags.
+**
+** The value returned includes space to create a copy of the Expr struct
+** itself and the buffer referred to by Expr.u.zToken, if any.
+**
+** If the EXPRDUP_REDUCE flag is set, then the return value includes 
+** space to duplicate all Expr nodes in the tree formed by Expr.pLeft 
+** and Expr.pRight variables (but not for any structures pointed to or 
+** descended from the Expr.x.pList or Expr.x.pSelect variables).
+*/
+static int dupedExprSize(Expr *p, int flags){
+  int nByte = 0;
+  if( p ){
+    nByte = dupedExprNodeSize(p, flags);
+    if( flags&EXPRDUP_REDUCE ){
+      nByte += dupedExprSize(p->pLeft, flags) + dupedExprSize(p->pRight, flags);
+    }
+  }
+  return nByte;
+}
+
+/*
+** This function is similar to sqlite3ExprDup(), except that if pzBuffer 
+** is not NULL then *pzBuffer is assumed to point to a buffer large enough 
+** to store the copy of expression p, the copies of p->u.zToken
+** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
+** if any. Before returning, *pzBuffer is set to the first byte passed the
+** portion of the buffer copied into by this function.
+*/
+static Expr *exprDup(sqlite3 *db, Expr *p, int flags, u8 **pzBuffer){
+  Expr *pNew = 0;                      /* Value to return */
+  if( p ){
+    const int isReduced = (flags&EXPRDUP_REDUCE);
+    u8 *zAlloc;
+    u32 staticFlag = 0;
+
+    assert( pzBuffer==0 || isReduced );
+
+    /* Figure out where to write the new Expr structure. */
+    if( pzBuffer ){
+      zAlloc = *pzBuffer;
+      staticFlag = EP_Static;
+    }else{
+      zAlloc = sqlite3DbMallocRaw(db, dupedExprSize(p, flags));
+    }
+    pNew = (Expr *)zAlloc;
+
+    if( pNew ){
+      /* Set nNewSize to the size allocated for the structure pointed to
+      ** by pNew. This is either EXPR_FULLSIZE, EXPR_REDUCEDSIZE or
+      ** EXPR_TOKENONLYSIZE. nToken is set to the number of bytes consumed
+      ** by the copy of the p->u.zToken string (if any).
+      */
+      const unsigned nStructSize = dupedExprStructSize(p, flags);
+      const int nNewSize = nStructSize & 0xfff;
+      int nToken;
+      if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+        nToken = sqlite3Strlen30(p->u.zToken) + 1;
+      }else{
+        nToken = 0;
+      }
+      if( isReduced ){
+        assert( ExprHasProperty(p, EP_Reduced)==0 );
+        memcpy(zAlloc, p, nNewSize);
+      }else{
+        int nSize = exprStructSize(p);
+        memcpy(zAlloc, p, nSize);
+        memset(&zAlloc[nSize], 0, EXPR_FULLSIZE-nSize);
+      }
+
+      /* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
+      pNew->flags &= ~(EP_Reduced|EP_TokenOnly|EP_Static);
+      pNew->flags |= nStructSize & (EP_Reduced|EP_TokenOnly);
+      pNew->flags |= staticFlag;
+
+      /* Copy the p->u.zToken string, if any. */
+      if( nToken ){
+        char *zToken = pNew->u.zToken = (char*)&zAlloc[nNewSize];
+        memcpy(zToken, p->u.zToken, nToken);
+      }
+
+      if( 0==((p->flags|pNew->flags) & EP_TokenOnly) ){
+        /* Fill in the pNew->x.pSelect or pNew->x.pList member. */
+        if( ExprHasProperty(p, EP_xIsSelect) ){
+          pNew->x.pSelect = sqlite3SelectDup(db, p->x.pSelect, isReduced);
+        }else{
+          pNew->x.pList = sqlite3ExprListDup(db, p->x.pList, isReduced);
+        }
+      }
+
+      /* Fill in pNew->pLeft and pNew->pRight. */
+      if( ExprHasAnyProperty(pNew, EP_Reduced|EP_TokenOnly) ){
+        zAlloc += dupedExprNodeSize(p, flags);
+        if( ExprHasProperty(pNew, EP_Reduced) ){
+          pNew->pLeft = exprDup(db, p->pLeft, EXPRDUP_REDUCE, &zAlloc);
+          pNew->pRight = exprDup(db, p->pRight, EXPRDUP_REDUCE, &zAlloc);
+        }
+        if( pzBuffer ){
+          *pzBuffer = zAlloc;
+        }
+      }else{
+        pNew->flags2 = 0;
+        if( !ExprHasAnyProperty(p, EP_TokenOnly) ){
+          pNew->pLeft = sqlite3ExprDup(db, p->pLeft, 0);
+          pNew->pRight = sqlite3ExprDup(db, p->pRight, 0);
+        }
+      }
+
+    }
+  }
+  return pNew;
 }
 
 /*
@@ -56899,37 +74102,16 @@ SQLITE_PRIVATE void sqlite3DequoteExpr(sqlite3 *db, Expr *p){
 ** by subsequent calls to sqlite*ListAppend() routines.
 **
 ** Any tables that the SrcList might point to are not duplicated.
+**
+** The flags parameter contains a combination of the EXPRDUP_XXX flags.
+** If the EXPRDUP_REDUCE flag is set, then the structure returned is a
+** truncated version of the usual Expr structure that will be stored as
+** part of the in-memory representation of the database schema.
 */
-SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3 *db, Expr *p){
-  Expr *pNew;
-  if( p==0 ) return 0;
-  pNew = sqlite3DbMallocRaw(db, sizeof(*p) );
-  if( pNew==0 ) return 0;
-  memcpy(pNew, p, sizeof(*pNew));
-  if( p->token.z!=0 ){
-    pNew->token.z = (u8*)sqlite3DbStrNDup(db, (char*)p->token.z, p->token.n);
-    pNew->token.dyn = 1;
-  }else{
-    assert( pNew->token.z==0 );
-  }
-  pNew->span.z = 0;
-  pNew->pLeft = sqlite3ExprDup(db, p->pLeft);
-  pNew->pRight = sqlite3ExprDup(db, p->pRight);
-  pNew->pList = sqlite3ExprListDup(db, p->pList);
-  pNew->pSelect = sqlite3SelectDup(db, p->pSelect);
-  return pNew;
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3 *db, Expr *p, int flags){
+  return exprDup(db, p, flags, 0);
 }
-SQLITE_PRIVATE void sqlite3TokenCopy(sqlite3 *db, Token *pTo, Token *pFrom){
-  if( pTo->dyn ) sqlite3DbFree(db, (char*)pTo->z);
-  if( pFrom->z ){
-    pTo->n = pFrom->n;
-    pTo->z = (u8*)sqlite3DbStrNDup(db, (char*)pFrom->z, pFrom->n);
-    pTo->dyn = 1;
-  }else{
-    pTo->z = 0;
-  }
-}
-SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p){
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p, int flags){
   ExprList *pNew;
   struct ExprList_item *pItem, *pOldItem;
   int i;
@@ -56937,29 +74119,22 @@ SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p){
   pNew = sqlite3DbMallocRaw(db, sizeof(*pNew) );
   if( pNew==0 ) return 0;
   pNew->iECursor = 0;
-  pNew->nExpr = pNew->nAlloc = p->nExpr;
-  pNew->a = pItem = sqlite3DbMallocRaw(db,  p->nExpr*sizeof(p->a[0]) );
+  pNew->nExpr = i = p->nExpr;
+  if( (flags & EXPRDUP_REDUCE)==0 ) for(i=1; i<p->nExpr; i+=i){}
+  pNew->a = pItem = sqlite3DbMallocRaw(db,  i*sizeof(p->a[0]) );
   if( pItem==0 ){
     sqlite3DbFree(db, pNew);
     return 0;
   } 
   pOldItem = p->a;
   for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
-    Expr *pNewExpr, *pOldExpr;
-    pItem->pExpr = pNewExpr = sqlite3ExprDup(db, pOldExpr = pOldItem->pExpr);
-    if( pOldExpr->span.z!=0 && pNewExpr ){
-      /* Always make a copy of the span for top-level expressions in the
-      ** expression list.  The logic in SELECT processing that determines
-      ** the names of columns in the result set needs this information */
-      sqlite3TokenCopy(db, &pNewExpr->span, &pOldExpr->span);
-    }
-    assert( pNewExpr==0 || pNewExpr->span.z!=0 
-            || pOldExpr->span.z==0
-            || db->mallocFailed );
+    Expr *pOldExpr = pOldItem->pExpr;
+    pItem->pExpr = sqlite3ExprDup(db, pOldExpr, flags);
     pItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pItem->zSpan = sqlite3DbStrDup(db, pOldItem->zSpan);
     pItem->sortOrder = pOldItem->sortOrder;
     pItem->done = 0;
-    pItem->iCol = pOldItem->iCol;
+    pItem->iOrderByCol = pOldItem->iOrderByCol;
     pItem->iAlias = pOldItem->iAlias;
   }
   return pNew;
@@ -56973,7 +74148,7 @@ SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p){
 */
 #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
  || !defined(SQLITE_OMIT_SUBQUERY)
-SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p){
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p, int flags){
   SrcList *pNew;
   int i;
   int nByte;
@@ -56991,7 +74166,9 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p){
     pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
     pNewItem->jointype = pOldItem->jointype;
     pNewItem->iCursor = pOldItem->iCursor;
-    pNewItem->isPopulated = pOldItem->isPopulated;
+    pNewItem->addrFillSub = pOldItem->addrFillSub;
+    pNewItem->regReturn = pOldItem->regReturn;
+    pNewItem->isCorrelated = pOldItem->isCorrelated;
     pNewItem->zIndex = sqlite3DbStrDup(db, pOldItem->zIndex);
     pNewItem->notIndexed = pOldItem->notIndexed;
     pNewItem->pIndex = pOldItem->pIndex;
@@ -56999,8 +74176,8 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p){
     if( pTab ){
       pTab->nRef++;
     }
-    pNewItem->pSelect = sqlite3SelectDup(db, pOldItem->pSelect);
-    pNewItem->pOn = sqlite3ExprDup(db, pOldItem->pOn);
+    pNewItem->pSelect = sqlite3SelectDup(db, pOldItem->pSelect, flags);
+    pNewItem->pOn = sqlite3ExprDup(db, pOldItem->pOn, flags);
     pNewItem->pUsing = sqlite3IdListDup(db, pOldItem->pUsing);
     pNewItem->colUsed = pOldItem->colUsed;
   }
@@ -57012,12 +74189,15 @@ SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3 *db, IdList *p){
   if( p==0 ) return 0;
   pNew = sqlite3DbMallocRaw(db, sizeof(*pNew) );
   if( pNew==0 ) return 0;
-  pNew->nId = pNew->nAlloc = p->nId;
+  pNew->nId = p->nId;
   pNew->a = sqlite3DbMallocRaw(db, p->nId*sizeof(p->a[0]) );
   if( pNew->a==0 ){
     sqlite3DbFree(db, pNew);
     return 0;
   }
+  /* Note that because the size of the allocation for p->a[] is not
+  ** necessarily a power of two, sqlite3IdListAppend() may not be called
+  ** on the duplicate created by this function. */
   for(i=0; i<p->nId; i++){
     struct IdList_item *pNewItem = &pNew->a[i];
     struct IdList_item *pOldItem = &p->a[i];
@@ -57026,21 +74206,23 @@ SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3 *db, IdList *p){
   }
   return pNew;
 }
-SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p){
-  Select *pNew;
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
+  Select *pNew, *pPrior;
   if( p==0 ) return 0;
   pNew = sqlite3DbMallocRaw(db, sizeof(*p) );
   if( pNew==0 ) return 0;
-  pNew->pEList = sqlite3ExprListDup(db, p->pEList);
-  pNew->pSrc = sqlite3SrcListDup(db, p->pSrc);
-  pNew->pWhere = sqlite3ExprDup(db, p->pWhere);
-  pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy);
-  pNew->pHaving = sqlite3ExprDup(db, p->pHaving);
-  pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy);
+  pNew->pEList = sqlite3ExprListDup(db, p->pEList, flags);
+  pNew->pSrc = sqlite3SrcListDup(db, p->pSrc, flags);
+  pNew->pWhere = sqlite3ExprDup(db, p->pWhere, flags);
+  pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy, flags);
+  pNew->pHaving = sqlite3ExprDup(db, p->pHaving, flags);
+  pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, flags);
   pNew->op = p->op;
-  pNew->pPrior = sqlite3SelectDup(db, p->pPrior);
-  pNew->pLimit = sqlite3ExprDup(db, p->pLimit);
-  pNew->pOffset = sqlite3ExprDup(db, p->pOffset);
+  pNew->pPrior = pPrior = sqlite3SelectDup(db, p->pPrior, flags);
+  if( pPrior ) pPrior->pNext = pNew;
+  pNew->pNext = 0;
+  pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
+  pNew->pOffset = sqlite3ExprDup(db, p->pOffset, flags);
   pNew->iLimit = 0;
   pNew->iOffset = 0;
   pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
@@ -57051,7 +74233,7 @@ SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p){
   return pNew;
 }
 #else
-SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p){
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
   assert( p==0 );
   return 0;
 }
@@ -57061,12 +74243,15 @@ SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, Select *p){
 /*
 ** Add a new element to the end of an expression list.  If pList is
 ** initially NULL, then create a new expression list.
+**
+** If a memory allocation error occurs, the entire list is freed and
+** NULL is returned.  If non-NULL is returned, then it is guaranteed
+** that the new entry was successfully appended.
 */
 SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(
   Parse *pParse,          /* Parsing context */
   ExprList *pList,        /* List to which to append. Might be NULL */
-  Expr *pExpr,            /* Expression to be appended */
-  Token *pName            /* AS keyword for the expression */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
 ){
   sqlite3 *db = pParse->db;
   if( pList==0 ){
@@ -57074,25 +74259,22 @@ SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(
     if( pList==0 ){
       goto no_mem;
     }
-    assert( pList->nAlloc==0 );
-  }
-  if( pList->nAlloc<=pList->nExpr ){
+    pList->a = sqlite3DbMallocRaw(db, sizeof(pList->a[0]));
+    if( pList->a==0 ) goto no_mem;
+  }else if( (pList->nExpr & (pList->nExpr-1))==0 ){
     struct ExprList_item *a;
-    int n = pList->nAlloc*2 + 4;
-    a = sqlite3DbRealloc(db, pList->a, n*sizeof(pList->a[0]));
+    assert( pList->nExpr>0 );
+    a = sqlite3DbRealloc(db, pList->a, pList->nExpr*2*sizeof(pList->a[0]));
     if( a==0 ){
       goto no_mem;
     }
     pList->a = a;
-    pList->nAlloc = sqlite3DbMallocSize(db, a)/sizeof(a[0]);
   }
   assert( pList->a!=0 );
-  if( pExpr || pName ){
+  if( 1 ){
     struct ExprList_item *pItem = &pList->a[pList->nExpr++];
     memset(pItem, 0, sizeof(*pItem));
-    pItem->zName = sqlite3NameFromToken(db, pName);
     pItem->pExpr = pExpr;
-    pItem->iAlias = 0;
   }
   return pList;
 
@@ -57103,6 +74285,56 @@ no_mem:
   return 0;
 }
 
+/*
+** Set the ExprList.a[].zName element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pName should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetName(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  Token *pName,           /* Name to be added */
+  int dequote             /* True to cause the name to be dequoted */
+){
+  assert( pList!=0 || pParse->db->mallocFailed!=0 );
+  if( pList ){
+    struct ExprList_item *pItem;
+    assert( pList->nExpr>0 );
+    pItem = &pList->a[pList->nExpr-1];
+    assert( pItem->zName==0 );
+    pItem->zName = sqlite3DbStrNDup(pParse->db, pName->z, pName->n);
+    if( dequote && pItem->zName ) sqlite3Dequote(pItem->zName);
+  }
+}
+
+/*
+** Set the ExprList.a[].zSpan element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pSpan should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetSpan(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  ExprSpan *pSpan         /* The span to be added */
+){
+  sqlite3 *db = pParse->db;
+  assert( pList!=0 || db->mallocFailed!=0 );
+  if( pList ){
+    struct ExprList_item *pItem = &pList->a[pList->nExpr-1];
+    assert( pList->nExpr>0 );
+    assert( db->mallocFailed || pItem->pExpr==pSpan->pExpr );
+    sqlite3DbFree(db, pItem->zSpan);
+    pItem->zSpan = sqlite3DbStrNDup(db, (char*)pSpan->zStart,
+                                    (int)(pSpan->zEnd - pSpan->zStart));
+  }
+}
+
 /*
 ** If the expression list pEList contains more than iLimit elements,
 ** leave an error message in pParse.
@@ -57127,11 +74359,11 @@ SQLITE_PRIVATE void sqlite3ExprListDelete(sqlite3 *db, ExprList *pList){
   int i;
   struct ExprList_item *pItem;
   if( pList==0 ) return;
-  assert( pList->a!=0 || (pList->nExpr==0 && pList->nAlloc==0) );
-  assert( pList->nExpr<=pList->nAlloc );
+  assert( pList->a!=0 || pList->nExpr==0 );
   for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
     sqlite3ExprDelete(db, pItem->pExpr);
     sqlite3DbFree(db, pItem->zName);
+    sqlite3DbFree(db, pItem->zSpan);
   }
   sqlite3DbFree(db, pList->a);
   sqlite3DbFree(db, pList);
@@ -57170,12 +74402,6 @@ static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
     case TK_COLUMN:
     case TK_AGG_FUNCTION:
     case TK_AGG_COLUMN:
-#ifndef SQLITE_OMIT_SUBQUERY
-    case TK_SELECT:
-    case TK_EXISTS:
-      testcase( pExpr->op==TK_SELECT );
-      testcase( pExpr->op==TK_EXISTS );
-#endif
       testcase( pExpr->op==TK_ID );
       testcase( pExpr->op==TK_COLUMN );
       testcase( pExpr->op==TK_AGG_FUNCTION );
@@ -57183,6 +74409,8 @@ static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
       pWalker->u.i = 0;
       return WRC_Abort;
     default:
+      testcase( pExpr->op==TK_SELECT ); /* selectNodeIsConstant will disallow */
+      testcase( pExpr->op==TK_EXISTS ); /* selectNodeIsConstant will disallow */
       return WRC_Continue;
   }
 }
@@ -57243,15 +74471,17 @@ SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr *p){
 */
 SQLITE_PRIVATE int sqlite3ExprIsInteger(Expr *p, int *pValue){
   int rc = 0;
+
+  /* If an expression is an integer literal that fits in a signed 32-bit
+  ** integer, then the EP_IntValue flag will have already been set */
+  assert( p->op!=TK_INTEGER || (p->flags & EP_IntValue)!=0
+           || sqlite3GetInt32(p->u.zToken, &rc)==0 );
+
   if( p->flags & EP_IntValue ){
-    *pValue = p->iTable;
+    *pValue = p->u.iValue;
     return 1;
   }
   switch( p->op ){
-    case TK_INTEGER: {
-      rc = sqlite3GetInt32((char*)p->token.z, pValue);
-      break;
-    }
     case TK_UPLUS: {
       rc = sqlite3ExprIsInteger(p->pLeft, pValue);
       break;
@@ -57266,14 +74496,97 @@ SQLITE_PRIVATE int sqlite3ExprIsInteger(Expr *p, int *pValue){
     }
     default: break;
   }
-  if( rc ){
-    p->op = TK_INTEGER;
-    p->flags |= EP_IntValue;
-    p->iTable = *pValue;
-  }
   return rc;
 }
 
+/*
+** Return FALSE if there is no chance that the expression can be NULL.
+**
+** If the expression might be NULL or if the expression is too complex
+** to tell return TRUE.  
+**
+** This routine is used as an optimization, to skip OP_IsNull opcodes
+** when we know that a value cannot be NULL.  Hence, a false positive
+** (returning TRUE when in fact the expression can never be NULL) might
+** be a small performance hit but is otherwise harmless.  On the other
+** hand, a false negative (returning FALSE when the result could be NULL)
+** will likely result in an incorrect answer.  So when in doubt, return
+** TRUE.
+*/
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr *p){
+  u8 op;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER:
+    case TK_STRING:
+    case TK_FLOAT:
+    case TK_BLOB:
+      return 0;
+    default:
+      return 1;
+  }
+}
+
+/*
+** Generate an OP_IsNull instruction that tests register iReg and jumps
+** to location iDest if the value in iReg is NULL.  The value in iReg 
+** was computed by pExpr.  If we can look at pExpr at compile-time and
+** determine that it can never generate a NULL, then the OP_IsNull operation
+** can be omitted.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeIsNullJump(
+  Vdbe *v,            /* The VDBE under construction */
+  const Expr *pExpr,  /* Only generate OP_IsNull if this expr can be NULL */
+  int iReg,           /* Test the value in this register for NULL */
+  int iDest           /* Jump here if the value is null */
+){
+  if( sqlite3ExprCanBeNull(pExpr) ){
+    sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iDest);
+  }
+}
+
+/*
+** Return TRUE if the given expression is a constant which would be
+** unchanged by OP_Affinity with the affinity given in the second
+** argument.
+**
+** This routine is used to determine if the OP_Affinity operation
+** can be omitted.  When in doubt return FALSE.  A false negative
+** is harmless.  A false positive, however, can result in the wrong
+** answer.
+*/
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr *p, char aff){
+  u8 op;
+  if( aff==SQLITE_AFF_NONE ) return 1;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER: {
+      return aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_FLOAT: {
+      return aff==SQLITE_AFF_REAL || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_STRING: {
+      return aff==SQLITE_AFF_TEXT;
+    }
+    case TK_BLOB: {
+      return 1;
+    }
+    case TK_COLUMN: {
+      assert( p->iTable>=0 );  /* p cannot be part of a CHECK constraint */
+      return p->iColumn<0
+          && (aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC);
+    }
+    default: {
+      return 0;
+    }
+  }
+}
+
 /*
 ** Return TRUE if the given string is a row-id column name.
 */
@@ -57285,14 +74598,16 @@ SQLITE_PRIVATE int sqlite3IsRowid(const char *z){
 }
 
 /*
-** Return true if the IN operator optimization is enabled and
-** the SELECT statement p exists and is of the
-** simple form:
+** Return true if we are able to the IN operator optimization on a
+** query of the form
 **
-**     SELECT <column> FROM <table>
+**       x IN (SELECT ...)
 **
-** If this is the case, it may be possible to use an existing table
-** or index instead of generating an epheremal table.
+** Where the SELECT... clause is as specified by the parameter to this
+** routine.
+**
+** The Select object passed in has already been preprocessed and no
+** errors have been found.
 */
 #ifndef SQLITE_OMIT_SUBQUERY
 static int isCandidateForInOpt(Select *p){
@@ -57302,19 +74617,21 @@ static int isCandidateForInOpt(Select *p){
   if( p==0 ) return 0;                   /* right-hand side of IN is SELECT */
   if( p->pPrior ) return 0;              /* Not a compound SELECT */
   if( p->selFlags & (SF_Distinct|SF_Aggregate) ){
-      return 0; /* No DISTINCT keyword and no aggregate functions */
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
+    return 0; /* No DISTINCT keyword and no aggregate functions */
   }
-  if( p->pGroupBy ) return 0;            /* Has no GROUP BY clause */
+  assert( p->pGroupBy==0 );              /* Has no GROUP BY clause */
   if( p->pLimit ) return 0;              /* Has no LIMIT clause */
-  if( p->pOffset ) return 0;
+  assert( p->pOffset==0 );               /* No LIMIT means no OFFSET */
   if( p->pWhere ) return 0;              /* Has no WHERE clause */
   pSrc = p->pSrc;
   assert( pSrc!=0 );
   if( pSrc->nSrc!=1 ) return 0;          /* Single term in FROM clause */
-  if( pSrc->a[0].pSelect ) return 0;     /* FROM clause is not a subquery */
+  if( pSrc->a[0].pSelect ) return 0;     /* FROM is not a subquery or view */
   pTab = pSrc->a[0].pTab;
-  if( pTab==0 ) return 0;
-  if( pTab->pSelect ) return 0;          /* FROM clause is not a view */
+  if( NEVER(pTab==0) ) return 0;
+  assert( pTab->pSelect==0 );            /* FROM clause is not a view */
   if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
   pEList = p->pEList;
   if( pEList->nExpr!=1 ) return 0;       /* One column in the result set */
@@ -57323,51 +74640,60 @@ static int isCandidateForInOpt(Select *p){
 }
 #endif /* SQLITE_OMIT_SUBQUERY */
 
+/*
+** Code an OP_Once instruction and allocate space for its flag. Return the 
+** address of the new instruction.
+*/
+SQLITE_PRIVATE int sqlite3CodeOnce(Parse *pParse){
+  Vdbe *v = sqlite3GetVdbe(pParse);      /* Virtual machine being coded */
+  return sqlite3VdbeAddOp1(v, OP_Once, pParse->nOnce++);
+}
+
 /*
 ** This function is used by the implementation of the IN (...) operator.
 ** It's job is to find or create a b-tree structure that may be used
 ** either to test for membership of the (...) set or to iterate through
 ** its members, skipping duplicates.
 **
-** The cursor opened on the structure (database table, database index 
+** The index of the cursor opened on the b-tree (database table, database index 
 ** or ephermal table) is stored in pX->iTable before this function returns.
-** The returned value indicates the structure type, as follows:
+** The returned value of this function indicates the b-tree type, as follows:
 **
 **   IN_INDEX_ROWID - The cursor was opened on a database table.
 **   IN_INDEX_INDEX - The cursor was opened on a database index.
 **   IN_INDEX_EPH -   The cursor was opened on a specially created and
 **                    populated epheremal table.
 **
-** An existing structure may only be used if the SELECT is of the simple
+** An existing b-tree may only be used if the SELECT is of the simple
 ** form:
 **
 **     SELECT <column> FROM <table>
 **
-** If prNotFound parameter is 0, then the structure will be used to iterate
+** If the prNotFound parameter is 0, then the b-tree will be used to iterate
 ** through the set members, skipping any duplicates. In this case an
 ** epheremal table must be used unless the selected <column> is guaranteed
 ** to be unique - either because it is an INTEGER PRIMARY KEY or it
-** is unique by virtue of a constraint or implicit index.
+** has a UNIQUE constraint or UNIQUE index.
 **
-** If the prNotFound parameter is not 0, then the structure will be used 
+** If the prNotFound parameter is not 0, then the b-tree will be used 
 ** for fast set membership tests. In this case an epheremal table must 
 ** be used unless <column> is an INTEGER PRIMARY KEY or an index can 
 ** be found with <column> as its left-most column.
 **
-** When the structure is being used for set membership tests, the user
+** When the b-tree is being used for membership tests, the calling function
 ** needs to know whether or not the structure contains an SQL NULL 
 ** value in order to correctly evaluate expressions like "X IN (Y, Z)".
-** If there is a chance that the structure may contain a NULL value at
+** If there is any chance that the (...) might contain a NULL value at
 ** runtime, then a register is allocated and the register number written
-** to *prNotFound. If there is no chance that the structure contains a
+** to *prNotFound. If there is no chance that the (...) contains a
 ** NULL value, then *prNotFound is left unchanged.
 **
 ** If a register is allocated and its location stored in *prNotFound, then
-** its initial value is NULL. If the structure does not remain constant
-** for the duration of the query (i.e. the set is a correlated sub-select), 
-** the value of the allocated register is reset to NULL each time the 
-** structure is repopulated. This allows the caller to use vdbe code 
-** equivalent to the following:
+** its initial value is NULL.  If the (...) does not remain constant
+** for the duration of the query (i.e. the SELECT within the (...)
+** is a correlated subquery) then the value of the allocated register is
+** reset to NULL each time the subquery is rerun. This allows the
+** caller to use vdbe code equivalent to the following:
 **
 **   if( register==NULL ){
 **     has_null = <test if data structure contains null>
@@ -57379,26 +74705,38 @@ static int isCandidateForInOpt(Select *p){
 */
 #ifndef SQLITE_OMIT_SUBQUERY
 SQLITE_PRIVATE int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
-  Select *p;
-  int eType = 0;
-  int iTab = pParse->nTab++;
-  int mustBeUnique = !prNotFound;
+  Select *p;                            /* SELECT to the right of IN operator */
+  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
+  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
+  int mustBeUnique = (prNotFound==0);   /* True if RHS must be unique */
+  Vdbe *v = sqlite3GetVdbe(pParse);     /* Virtual machine being coded */
 
-  /* The follwing if(...) expression is true if the SELECT is of the 
-  ** simple form:
-  **
-  **     SELECT <column> FROM <table>
-  **
-  ** If this is the case, it may be possible to use an existing table
-  ** or index instead of generating an epheremal table.
+  assert( pX->op==TK_IN );
+
+  /* Check to see if an existing table or index can be used to
+  ** satisfy the query.  This is preferable to generating a new 
+  ** ephemeral table.
   */
-  p = pX->pSelect;
-  if( isCandidateForInOpt(p) ){
-    sqlite3 *db = pParse->db;
-    Index *pIdx;
-    Expr *pExpr = p->pEList->a[0].pExpr;
-    int iCol = pExpr->iColumn;
-    Vdbe *v = sqlite3GetVdbe(pParse);
+  p = (ExprHasProperty(pX, EP_xIsSelect) ? pX->x.pSelect : 0);
+  if( ALWAYS(pParse->nErr==0) && isCandidateForInOpt(p) ){
+    sqlite3 *db = pParse->db;              /* Database connection */
+    Table *pTab;                           /* Table <table>. */
+    Expr *pExpr;                           /* Expression <column> */
+    int iCol;                              /* Index of column <column> */
+    int iDb;                               /* Database idx for pTab */
+
+    assert( p );                        /* Because of isCandidateForInOpt(p) */
+    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
+    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
+    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
+    pTab = p->pSrc->a[0].pTab;
+    pExpr = p->pEList->a[0].pExpr;
+    iCol = pExpr->iColumn;
+   
+    /* Code an OP_VerifyCookie and OP_TableLock for <table>. */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    sqlite3CodeVerifySchema(pParse, iDb);
+    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
 
     /* This function is only called from two places. In both cases the vdbe
     ** has already been allocated. So assume sqlite3GetVdbe() is always
@@ -57406,52 +74744,40 @@ SQLITE_PRIVATE int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
     */
     assert(v);
     if( iCol<0 ){
-      int iMem = ++pParse->nMem;
       int iAddr;
-      Table *pTab = p->pSrc->a[0].pTab;
-      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
-      sqlite3VdbeUsesBtree(v, iDb);
 
-      iAddr = sqlite3VdbeAddOp1(v, OP_If, iMem);
-      sqlite3VdbeAddOp2(v, OP_Integer, 1, iMem);
+      iAddr = sqlite3CodeOnce(pParse);
 
       sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
       eType = IN_INDEX_ROWID;
 
       sqlite3VdbeJumpHere(v, iAddr);
     }else{
-      /* The collation sequence used by the comparison. If an index is to 
+      Index *pIdx;                         /* Iterator variable */
+
+      /* The collation sequence used by the comparison. If an index is to
       ** be used in place of a temp-table, it must be ordered according
-      ** to this collation sequence.
-      */
+      ** to this collation sequence.  */
       CollSeq *pReq = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pExpr);
 
       /* Check that the affinity that will be used to perform the 
       ** comparison is the same as the affinity of the column. If
       ** it is not, it is not possible to use any index.
       */
-      Table *pTab = p->pSrc->a[0].pTab;
       char aff = comparisonAffinity(pX);
       int affinity_ok = (pTab->aCol[iCol].affinity==aff||aff==SQLITE_AFF_NONE);
 
       for(pIdx=pTab->pIndex; pIdx && eType==0 && affinity_ok; pIdx=pIdx->pNext){
         if( (pIdx->aiColumn[0]==iCol)
-         && (pReq==sqlite3FindCollSeq(db, ENC(db), pIdx->azColl[0], -1, 0))
+         && sqlite3FindCollSeq(db, ENC(db), pIdx->azColl[0], 0)==pReq
          && (!mustBeUnique || (pIdx->nColumn==1 && pIdx->onError!=OE_None))
         ){
-          int iDb;
-          int iMem = ++pParse->nMem;
           int iAddr;
           char *pKey;
   
           pKey = (char *)sqlite3IndexKeyinfo(pParse, pIdx);
-          iDb = sqlite3SchemaToIndex(db, pIdx->pSchema);
-          sqlite3VdbeUsesBtree(v, iDb);
-
-          iAddr = sqlite3VdbeAddOp1(v, OP_If, iMem);
-          sqlite3VdbeAddOp2(v, OP_Integer, 1, iMem);
+          iAddr = sqlite3CodeOnce(pParse);
   
-          sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pIdx->nColumn);
           sqlite3VdbeAddOp4(v, OP_OpenRead, iTab, pIdx->tnum, iDb,
                                pKey,P4_KEYINFO_HANDOFF);
           VdbeComment((v, "%s", pIdx->zName));
@@ -57460,6 +74786,7 @@ SQLITE_PRIVATE int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
           sqlite3VdbeJumpHere(v, iAddr);
           if( prNotFound && !pTab->aCol[iCol].notNull ){
             *prNotFound = ++pParse->nMem;
+            sqlite3VdbeAddOp2(v, OP_Null, 0, *prNotFound);
           }
         }
       }
@@ -57467,14 +74794,24 @@ SQLITE_PRIVATE int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
   }
 
   if( eType==0 ){
+    /* Could not found an existing table or index to use as the RHS b-tree.
+    ** We will have to generate an ephemeral table to do the job.
+    */
+    double savedNQueryLoop = pParse->nQueryLoop;
     int rMayHaveNull = 0;
     eType = IN_INDEX_EPH;
     if( prNotFound ){
       *prNotFound = rMayHaveNull = ++pParse->nMem;
-    }else if( pX->pLeft->iColumn<0 && pX->pSelect==0 ){
-      eType = IN_INDEX_ROWID;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, *prNotFound);
+    }else{
+      testcase( pParse->nQueryLoop>(double)1 );
+      pParse->nQueryLoop = (double)1;
+      if( pX->pLeft->iColumn<0 && !ExprHasAnyProperty(pX, EP_xIsSelect) ){
+        eType = IN_INDEX_ROWID;
+      }
     }
     sqlite3CodeSubselect(pParse, pX, rMayHaveNull, eType==IN_INDEX_ROWID);
+    pParse->nQueryLoop = savedNQueryLoop;
   }else{
     pX->iTable = iTab;
   }
@@ -57483,8 +74820,8 @@ SQLITE_PRIVATE int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
 #endif
 
 /*
-** Generate code for scalar subqueries used as an expression
-** and IN operators.  Examples:
+** Generate code for scalar subqueries used as a subquery expression, EXISTS,
+** or IN operators.  Examples:
 **
 **     (SELECT a FROM b)          -- subquery
 **     EXISTS (SELECT a FROM b)   -- EXISTS subquery
@@ -57499,18 +74836,34 @@ SQLITE_PRIVATE int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
 ** to some integer key column of a table B-Tree. In this case, use an
 ** intkey B-Tree to store the set of IN(...) values instead of the usual
 ** (slower) variable length keys B-Tree.
+**
+** If rMayHaveNull is non-zero, that means that the operation is an IN
+** (not a SELECT or EXISTS) and that the RHS might contains NULLs.
+** Furthermore, the IN is in a WHERE clause and that we really want
+** to iterate over the RHS of the IN operator in order to quickly locate
+** all corresponding LHS elements.  All this routine does is initialize
+** the register given by rMayHaveNull to NULL.  Calling routines will take
+** care of changing this register value to non-NULL if the RHS is NULL-free.
+**
+** If rMayHaveNull is zero, that means that the subquery is being used
+** for membership testing only.  There is no need to initialize any
+** registers to indicate the presense or absence of NULLs on the RHS.
+**
+** For a SELECT or EXISTS operator, return the register that holds the
+** result.  For IN operators or if an error occurs, the return value is 0.
 */
 #ifndef SQLITE_OMIT_SUBQUERY
-SQLITE_PRIVATE void sqlite3CodeSubselect(
-  Parse *pParse, 
-  Expr *pExpr, 
-  int rMayHaveNull,
-  int isRowid
+SQLITE_PRIVATE int sqlite3CodeSubselect(
+  Parse *pParse,          /* Parsing context */
+  Expr *pExpr,            /* The IN, SELECT, or EXISTS operator */
+  int rMayHaveNull,       /* Register that records whether NULLs exist in RHS */
+  int isRowid             /* If true, LHS of IN operator is a rowid */
 ){
-  int testAddr = 0;                       /* One-time test address */
+  int testAddr = -1;                      /* One-time test address */
+  int rReg = 0;                           /* Register storing resulting */
   Vdbe *v = sqlite3GetVdbe(pParse);
-  if( v==0 ) return;
-
+  if( NEVER(v==0) ) return 0;
+  sqlite3ExprCachePush(pParse);
 
   /* This code must be run in its entirety every time it is encountered
   ** if any of the following is true:
@@ -57522,19 +74875,26 @@ SQLITE_PRIVATE void sqlite3CodeSubselect(
   ** If all of the above are false, then we can run this code just once
   ** save the results, and reuse the same result on subsequent invocations.
   */
-  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->trigStack ){
-    int mem = ++pParse->nMem;
-    sqlite3VdbeAddOp1(v, OP_If, mem);
-    testAddr = sqlite3VdbeAddOp2(v, OP_Integer, 1, mem);
-    assert( testAddr>0 || pParse->db->mallocFailed );
+  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) ){
+    testAddr = sqlite3CodeOnce(pParse);
   }
 
+#ifndef SQLITE_OMIT_EXPLAIN
+  if( pParse->explain==2 ){
+    char *zMsg = sqlite3MPrintf(
+        pParse->db, "EXECUTE %s%s SUBQUERY %d", testAddr>=0?"":"CORRELATED ",
+        pExpr->op==TK_IN?"LIST":"SCALAR", pParse->iNextSelectId
+    );
+    sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
+  }
+#endif
+
   switch( pExpr->op ){
     case TK_IN: {
-      char affinity;
-      KeyInfo keyInfo;
-      int addr;        /* Address of OP_OpenEphemeral instruction */
-      Expr *pLeft = pExpr->pLeft;
+      char affinity;              /* Affinity of the LHS of the IN */
+      KeyInfo keyInfo;            /* Keyinfo for the generated table */
+      int addr;                   /* Address of OP_OpenEphemeral instruction */
+      Expr *pLeft = pExpr->pLeft; /* the LHS of the IN operator */
 
       if( rMayHaveNull ){
         sqlite3VdbeAddOp2(v, OP_Null, 0, rMayHaveNull);
@@ -57543,7 +74903,7 @@ SQLITE_PRIVATE void sqlite3CodeSubselect(
       affinity = sqlite3ExprAffinity(pLeft);
 
       /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
-      ** expression it is handled the same way. A virtual table is 
+      ** expression it is handled the same way.  An ephemeral table is 
       ** filled with single-field index keys representing the results
       ** from the SELECT or the <exprlist>.
       **
@@ -57557,10 +74917,11 @@ SQLITE_PRIVATE void sqlite3CodeSubselect(
       */
       pExpr->iTable = pParse->nTab++;
       addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pExpr->iTable, !isRowid);
+      if( rMayHaveNull==0 ) sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
       memset(&keyInfo, 0, sizeof(keyInfo));
       keyInfo.nField = 1;
 
-      if( pExpr->pSelect ){
+      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
         /* Case 1:     expr IN (SELECT ...)
         **
         ** Generate code to write the results of the select into the temporary
@@ -57571,17 +74932,18 @@ SQLITE_PRIVATE void sqlite3CodeSubselect(
 
         assert( !isRowid );
         sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
-        dest.affinity = (u8)affinity;
+        dest.affSdst = (u8)affinity;
         assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
-        if( sqlite3Select(pParse, pExpr->pSelect, &dest) ){
-          return;
+        pExpr->x.pSelect->iLimit = 0;
+        if( sqlite3Select(pParse, pExpr->x.pSelect, &dest) ){
+          return 0;
         }
-        pEList = pExpr->pSelect->pEList;
-        if( pEList && pEList->nExpr>0 ){ 
+        pEList = pExpr->x.pSelect->pEList;
+        if( ALWAYS(pEList!=0 && pEList->nExpr>0) ){ 
           keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
               pEList->a[0].pExpr);
         }
-      }else if( pExpr->pList ){
+      }else if( ALWAYS(pExpr->x.pList!=0) ){
         /* Case 2:     expr IN (exprlist)
         **
         ** For each expression, build an index key from the evaluation and
@@ -57590,7 +74952,7 @@ SQLITE_PRIVATE void sqlite3CodeSubselect(
         ** a column, use numeric affinity.
         */
         int i;
-        ExprList *pList = pExpr->pList;
+        ExprList *pList = pExpr->x.pList;
         struct ExprList_item *pItem;
         int r1, r2, r3;
 
@@ -57605,30 +74967,32 @@ SQLITE_PRIVATE void sqlite3CodeSubselect(
         sqlite3VdbeAddOp2(v, OP_Null, 0, r2);
         for(i=pList->nExpr, pItem=pList->a; i>0; i--, pItem++){
           Expr *pE2 = pItem->pExpr;
+          int iValToIns;
 
           /* If the expression is not constant then we will need to
           ** disable the test that was generated above that makes sure
           ** this code only executes once.  Because for a non-constant
           ** expression we need to rerun this code each time.
           */
-          if( testAddr && !sqlite3ExprIsConstant(pE2) ){
-            sqlite3VdbeChangeToNoop(v, testAddr-1, 2);
-            testAddr = 0;
+          if( testAddr>=0 && !sqlite3ExprIsConstant(pE2) ){
+            sqlite3VdbeChangeToNoop(v, testAddr);
+            testAddr = -1;
           }
 
           /* Evaluate the expression and insert it into the temp table */
-          pParse->disableColCache++;
-          r3 = sqlite3ExprCodeTarget(pParse, pE2, r1);
-          assert( pParse->disableColCache>0 );
-          pParse->disableColCache--;
-
-          if( isRowid ){
-            sqlite3VdbeAddOp2(v, OP_MustBeInt, r3, sqlite3VdbeCurrentAddr(v)+2);
-            sqlite3VdbeAddOp3(v, OP_Insert, pExpr->iTable, r2, r3);
+          if( isRowid && sqlite3ExprIsInteger(pE2, &iValToIns) ){
+            sqlite3VdbeAddOp3(v, OP_InsertInt, pExpr->iTable, r2, iValToIns);
           }else{
-            sqlite3VdbeAddOp4(v, OP_MakeRecord, r3, 1, r2, &affinity, 1);
-            sqlite3ExprCacheAffinityChange(pParse, r3, 1);
-            sqlite3VdbeAddOp2(v, OP_IdxInsert, pExpr->iTable, r2);
+            r3 = sqlite3ExprCodeTarget(pParse, pE2, r1);
+            if( isRowid ){
+              sqlite3VdbeAddOp2(v, OP_MustBeInt, r3,
+                                sqlite3VdbeCurrentAddr(v)+2);
+              sqlite3VdbeAddOp3(v, OP_Insert, pExpr->iTable, r2, r3);
+            }else{
+              sqlite3VdbeAddOp4(v, OP_MakeRecord, r3, 1, r2, &affinity, 1);
+              sqlite3ExprCacheAffinityChange(pParse, r3, 1);
+              sqlite3VdbeAddOp2(v, OP_IdxInsert, pExpr->iTable, r2);
+            }
           }
         }
         sqlite3ReleaseTempReg(pParse, r1);
@@ -57641,41 +75005,186 @@ SQLITE_PRIVATE void sqlite3CodeSubselect(
     }
 
     case TK_EXISTS:
-    case TK_SELECT: {
-      /* This has to be a scalar SELECT.  Generate code to put the
+    case TK_SELECT:
+    default: {
+      /* If this has to be a scalar SELECT.  Generate code to put the
       ** value of this select in a memory cell and record the number
-      ** of the memory cell in iColumn.
+      ** of the memory cell in iColumn.  If this is an EXISTS, write
+      ** an integer 0 (not exists) or 1 (exists) into a memory cell
+      ** and record that memory cell in iColumn.
       */
-      static const Token one = { (u8*)"1", 0, 1 };
-      Select *pSel;
-      SelectDest dest;
+      Select *pSel;                         /* SELECT statement to encode */
+      SelectDest dest;                      /* How to deal with SELECt result */
 
-      pSel = pExpr->pSelect;
+      testcase( pExpr->op==TK_EXISTS );
+      testcase( pExpr->op==TK_SELECT );
+      assert( pExpr->op==TK_EXISTS || pExpr->op==TK_SELECT );
+
+      assert( ExprHasProperty(pExpr, EP_xIsSelect) );
+      pSel = pExpr->x.pSelect;
       sqlite3SelectDestInit(&dest, 0, ++pParse->nMem);
       if( pExpr->op==TK_SELECT ){
         dest.eDest = SRT_Mem;
-        sqlite3VdbeAddOp2(v, OP_Null, 0, dest.iParm);
+        sqlite3VdbeAddOp2(v, OP_Null, 0, dest.iSDParm);
         VdbeComment((v, "Init subquery result"));
       }else{
         dest.eDest = SRT_Exists;
-        sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iParm);
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iSDParm);
         VdbeComment((v, "Init EXISTS result"));
       }
       sqlite3ExprDelete(pParse->db, pSel->pLimit);
-      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
+      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0,
+                                  &sqlite3IntTokens[1]);
+      pSel->iLimit = 0;
       if( sqlite3Select(pParse, pSel, &dest) ){
-        return;
+        return 0;
       }
-      pExpr->iColumn = dest.iParm;
+      rReg = dest.iSDParm;
+      ExprSetIrreducible(pExpr);
       break;
     }
   }
 
-  if( testAddr ){
-    sqlite3VdbeJumpHere(v, testAddr-1);
+  if( testAddr>=0 ){
+    sqlite3VdbeJumpHere(v, testAddr);
+  }
+  sqlite3ExprCachePop(pParse, 1);
+
+  return rReg;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for an IN expression.
+**
+**      x IN (SELECT ...)
+**      x IN (value, value, ...)
+**
+** The left-hand side (LHS) is a scalar expression.  The right-hand side (RHS)
+** is an array of zero or more values.  The expression is true if the LHS is
+** contained within the RHS.  The value of the expression is unknown (NULL)
+** if the LHS is NULL or if the LHS is not contained within the RHS and the
+** RHS contains one or more NULL values.
+**
+** This routine generates code will jump to destIfFalse if the LHS is not 
+** contained within the RHS.  If due to NULLs we cannot determine if the LHS
+** is contained in the RHS then jump to destIfNull.  If the LHS is contained
+** within the RHS then fall through.
+*/
+static void sqlite3ExprCodeIN(
+  Parse *pParse,        /* Parsing and code generating context */
+  Expr *pExpr,          /* The IN expression */
+  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
+  int destIfNull        /* Jump here if the results are unknown due to NULLs */
+){
+  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
+  char affinity;        /* Comparison affinity to use */
+  int eType;            /* Type of the RHS */
+  int r1;               /* Temporary use register */
+  Vdbe *v;              /* Statement under construction */
+
+  /* Compute the RHS.   After this step, the table with cursor
+  ** pExpr->iTable will contains the values that make up the RHS.
+  */
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* OOM detected prior to this routine */
+  VdbeNoopComment((v, "begin IN expr"));
+  eType = sqlite3FindInIndex(pParse, pExpr, &rRhsHasNull);
+
+  /* Figure out the affinity to use to create a key from the results
+  ** of the expression. affinityStr stores a static string suitable for
+  ** P4 of OP_MakeRecord.
+  */
+  affinity = comparisonAffinity(pExpr);
+
+  /* Code the LHS, the <expr> from "<expr> IN (...)".
+  */
+  sqlite3ExprCachePush(pParse);
+  r1 = sqlite3GetTempReg(pParse);
+  sqlite3ExprCode(pParse, pExpr->pLeft, r1);
+
+  /* If the LHS is NULL, then the result is either false or NULL depending
+  ** on whether the RHS is empty or not, respectively.
+  */
+  if( destIfNull==destIfFalse ){
+    /* Shortcut for the common case where the false and NULL outcomes are
+    ** the same. */
+    sqlite3VdbeAddOp2(v, OP_IsNull, r1, destIfNull);
+  }else{
+    int addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, r1);
+    sqlite3VdbeAddOp2(v, OP_Rewind, pExpr->iTable, destIfFalse);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfNull);
+    sqlite3VdbeJumpHere(v, addr1);
   }
 
-  return;
+  if( eType==IN_INDEX_ROWID ){
+    /* In this case, the RHS is the ROWID of table b-tree
+    */
+    sqlite3VdbeAddOp2(v, OP_MustBeInt, r1, destIfFalse);
+    sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, destIfFalse, r1);
+  }else{
+    /* In this case, the RHS is an index b-tree.
+    */
+    sqlite3VdbeAddOp4(v, OP_Affinity, r1, 1, 0, &affinity, 1);
+
+    /* If the set membership test fails, then the result of the 
+    ** "x IN (...)" expression must be either 0 or NULL. If the set
+    ** contains no NULL values, then the result is 0. If the set 
+    ** contains one or more NULL values, then the result of the
+    ** expression is also NULL.
+    */
+    if( rRhsHasNull==0 || destIfFalse==destIfNull ){
+      /* This branch runs if it is known at compile time that the RHS
+      ** cannot contain NULL values. This happens as the result
+      ** of a "NOT NULL" constraint in the database schema.
+      **
+      ** Also run this branch if NULL is equivalent to FALSE
+      ** for this particular IN operator.
+      */
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, pExpr->iTable, destIfFalse, r1, 1);
+
+    }else{
+      /* In this branch, the RHS of the IN might contain a NULL and
+      ** the presence of a NULL on the RHS makes a difference in the
+      ** outcome.
+      */
+      int j1, j2, j3;
+
+      /* First check to see if the LHS is contained in the RHS.  If so,
+      ** then the presence of NULLs in the RHS does not matter, so jump
+      ** over all of the code that follows.
+      */
+      j1 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, r1, 1);
+
+      /* Here we begin generating code that runs if the LHS is not
+      ** contained within the RHS.  Generate additional code that
+      ** tests the RHS for NULLs.  If the RHS contains a NULL then
+      ** jump to destIfNull.  If there are no NULLs in the RHS then
+      ** jump to destIfFalse.
+      */
+      j2 = sqlite3VdbeAddOp1(v, OP_NotNull, rRhsHasNull);
+      j3 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, rRhsHasNull, 1);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, rRhsHasNull);
+      sqlite3VdbeJumpHere(v, j3);
+      sqlite3VdbeAddOp2(v, OP_AddImm, rRhsHasNull, 1);
+      sqlite3VdbeJumpHere(v, j2);
+
+      /* Jump to the appropriate target depending on whether or not
+      ** the RHS contains a NULL
+      */
+      sqlite3VdbeAddOp2(v, OP_If, rRhsHasNull, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
+
+      /* The OP_Found at the top of this branch jumps here when true, 
+      ** causing the overall IN expression evaluation to fall through.
+      */
+      sqlite3VdbeJumpHere(v, j1);
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, r1);
+  sqlite3ExprCachePop(pParse, 1);
+  VdbeComment((v, "end IN expr"));
 }
 #endif /* SQLITE_OMIT_SUBQUERY */
 
@@ -57690,6 +75199,7 @@ static char *dup8bytes(Vdbe *v, const char *in){
   return out;
 }
 
+#ifndef SQLITE_OMIT_FLOATING_POINT
 /*
 ** Generate an instruction that will put the floating point
 ** value described by z[0..n-1] into register iMem.
@@ -57698,59 +75208,212 @@ static char *dup8bytes(Vdbe *v, const char *in){
 ** z[n] character is guaranteed to be something that does not look
 ** like the continuation of the number.
 */
-static void codeReal(Vdbe *v, const char *z, int n, int negateFlag, int iMem){
-  assert( z || v==0 || sqlite3VdbeDb(v)->mallocFailed );
-  assert( !z || !isdigit(z[n]) );
-  UNUSED_PARAMETER(n);
-  if( z ){
+static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
+  if( ALWAYS(z!=0) ){
     double value;
     char *zV;
-    sqlite3AtoF(z, &value);
-    if( sqlite3IsNaN(value) ){
-      sqlite3VdbeAddOp2(v, OP_Null, 0, iMem);
-    }else{
-      if( negateFlag ) value = -value;
-      zV = dup8bytes(v, (char*)&value);
-      sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
-    }
+    sqlite3AtoF(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
+    assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
+    if( negateFlag ) value = -value;
+    zV = dup8bytes(v, (char*)&value);
+    sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
   }
 }
+#endif
 
 
 /*
 ** Generate an instruction that will put the integer describe by
 ** text z[0..n-1] into register iMem.
 **
-** The z[] string will probably not be zero-terminated.  But the 
-** z[n] character is guaranteed to be something that does not look
-** like the continuation of the number.
+** Expr.u.zToken is always UTF8 and zero-terminated.
 */
-static void codeInteger(Vdbe *v, Expr *pExpr, int negFlag, int iMem){
-  const char *z;
+static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
+  Vdbe *v = pParse->pVdbe;
   if( pExpr->flags & EP_IntValue ){
-    int i = pExpr->iTable;
+    int i = pExpr->u.iValue;
+    assert( i>=0 );
     if( negFlag ) i = -i;
     sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
-  }else if( (z = (char*)pExpr->token.z)!=0 ){
-    int i;
-    int n = pExpr->token.n;
-    assert( !isdigit(z[n]) );
-    if( sqlite3GetInt32(z, &i) ){
-      if( negFlag ) i = -i;
-      sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
-    }else if( sqlite3FitsIn64Bits(z, negFlag) ){
-      i64 value;
+  }else{
+    int c;
+    i64 value;
+    const char *z = pExpr->u.zToken;
+    assert( z!=0 );
+    c = sqlite3Atoi64(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
+    if( c==0 || (c==2 && negFlag) ){
       char *zV;
-      sqlite3Atoi64(z, &value);
-      if( negFlag ) value = -value;
+      if( negFlag ){ value = c==2 ? SMALLEST_INT64 : -value; }
       zV = dup8bytes(v, (char*)&value);
       sqlite3VdbeAddOp4(v, OP_Int64, 0, iMem, 0, zV, P4_INT64);
     }else{
-      codeReal(v, z, n, negFlag, iMem);
+#ifdef SQLITE_OMIT_FLOATING_POINT
+      sqlite3ErrorMsg(pParse, "oversized integer: %s%s", negFlag ? "-" : "", z);
+#else
+      codeReal(v, z, negFlag, iMem);
+#endif
     }
   }
 }
 
+/*
+** Clear a cache entry.
+*/
+static void cacheEntryClear(Parse *pParse, struct yColCache *p){
+  if( p->tempReg ){
+    if( pParse->nTempReg<ArraySize(pParse->aTempReg) ){
+      pParse->aTempReg[pParse->nTempReg++] = p->iReg;
+    }
+    p->tempReg = 0;
+  }
+}
+
+
+/*
+** Record in the column cache that a particular column from a
+** particular table is stored in a particular register.
+*/
+SQLITE_PRIVATE void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
+  int i;
+  int minLru;
+  int idxLru;
+  struct yColCache *p;
+
+  assert( iReg>0 );  /* Register numbers are always positive */
+  assert( iCol>=-1 && iCol<32768 );  /* Finite column numbers */
+
+  /* The SQLITE_ColumnCache flag disables the column cache.  This is used
+  ** for testing only - to verify that SQLite always gets the same answer
+  ** with and without the column cache.
+  */
+  if( pParse->db->flags & SQLITE_ColumnCache ) return;
+
+  /* First replace any existing entry.
+  **
+  ** Actually, the way the column cache is currently used, we are guaranteed
+  ** that the object will never already be in cache.  Verify this guarantee.
+  */
+#ifndef NDEBUG
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    assert( p->iReg==0 || p->iTable!=iTab || p->iColumn!=iCol );
+  }
+#endif
+
+  /* Find an empty slot and replace it */
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    if( p->iReg==0 ){
+      p->iLevel = pParse->iCacheLevel;
+      p->iTable = iTab;
+      p->iColumn = iCol;
+      p->iReg = iReg;
+      p->tempReg = 0;
+      p->lru = pParse->iCacheCnt++;
+      return;
+    }
+  }
+
+  /* Replace the last recently used */
+  minLru = 0x7fffffff;
+  idxLru = -1;
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    if( p->lru<minLru ){
+      idxLru = i;
+      minLru = p->lru;
+    }
+  }
+  if( ALWAYS(idxLru>=0) ){
+    p = &pParse->aColCache[idxLru];
+    p->iLevel = pParse->iCacheLevel;
+    p->iTable = iTab;
+    p->iColumn = iCol;
+    p->iReg = iReg;
+    p->tempReg = 0;
+    p->lru = pParse->iCacheCnt++;
+    return;
+  }
+}
+
+/*
+** Indicate that registers between iReg..iReg+nReg-1 are being overwritten.
+** Purge the range of registers from the column cache.
+*/
+SQLITE_PRIVATE void sqlite3ExprCacheRemove(Parse *pParse, int iReg, int nReg){
+  int i;
+  int iLast = iReg + nReg - 1;
+  struct yColCache *p;
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    int r = p->iReg;
+    if( r>=iReg && r<=iLast ){
+      cacheEntryClear(pParse, p);
+      p->iReg = 0;
+    }
+  }
+}
+
+/*
+** Remember the current column cache context.  Any new entries added
+** added to the column cache after this call are removed when the
+** corresponding pop occurs.
+*/
+SQLITE_PRIVATE void sqlite3ExprCachePush(Parse *pParse){
+  pParse->iCacheLevel++;
+}
+
+/*
+** Remove from the column cache any entries that were added since the
+** the previous N Push operations.  In other words, restore the cache
+** to the state it was in N Pushes ago.
+*/
+SQLITE_PRIVATE void sqlite3ExprCachePop(Parse *pParse, int N){
+  int i;
+  struct yColCache *p;
+  assert( N>0 );
+  assert( pParse->iCacheLevel>=N );
+  pParse->iCacheLevel -= N;
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    if( p->iReg && p->iLevel>pParse->iCacheLevel ){
+      cacheEntryClear(pParse, p);
+      p->iReg = 0;
+    }
+  }
+}
+
+/*
+** When a cached column is reused, make sure that its register is
+** no longer available as a temp register.  ticket #3879:  that same
+** register might be in the cache in multiple places, so be sure to
+** get them all.
+*/
+static void sqlite3ExprCachePinRegister(Parse *pParse, int iReg){
+  int i;
+  struct yColCache *p;
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    if( p->iReg==iReg ){
+      p->tempReg = 0;
+    }
+  }
+}
+
+/*
+** Generate code to extract the value of the iCol-th column of a table.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(
+  Vdbe *v,        /* The VDBE under construction */
+  Table *pTab,    /* The table containing the value */
+  int iTabCur,    /* The cursor for this table */
+  int iCol,       /* Index of the column to extract */
+  int regOut      /* Extract the valud into this register */
+){
+  if( iCol<0 || iCol==pTab->iPKey ){
+    sqlite3VdbeAddOp2(v, OP_Rowid, iTabCur, regOut);
+  }else{
+    int op = IsVirtual(pTab) ? OP_VColumn : OP_Column;
+    sqlite3VdbeAddOp3(v, op, iTabCur, iCol, regOut);
+  }
+  if( iCol>=0 ){
+    sqlite3ColumnDefault(v, pTab, iCol, regOut);
+  }
+}
 
 /*
 ** Generate code that will extract the iColumn-th column from
@@ -57760,12 +75423,6 @@ static void codeInteger(Vdbe *v, Expr *pExpr, int negFlag, int iMem){
 **
 ** There must be an open cursor to pTab in iTable when this routine
 ** is called.  If iColumn<0 then code is generated that extracts the rowid.
-**
-** This routine might attempt to reuse the value of the column that
-** has already been loaded into a register.  The value will always
-** be used if it has not undergone any affinity changes.  But if
-** an affinity change has occurred, then the cached value will only be
-** used if allowAffChng is true.
 */
 SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(
   Parse *pParse,   /* Parsing and code generating context */
@@ -57773,69 +75430,40 @@ SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(
   int iColumn,     /* Index of the table column */
   int iTable,      /* The cursor pointing to the table */
   int iReg,        /* Store results here */
-  int allowAffChng /* True if prior affinity changes are OK */
+  u8 p5            /* P5 value for OP_Column */
 ){
   Vdbe *v = pParse->pVdbe;
   int i;
   struct yColCache *p;
 
-  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
-    if( p->iTable==iTable && p->iColumn==iColumn
-           && (!p->affChange || allowAffChng) ){
-#if 0
-      sqlite3VdbeAddOp0(v, OP_Noop);
-      VdbeComment((v, "OPT: tab%d.col%d -> r%d", iTable, iColumn, p->iReg));
-#endif
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    if( p->iReg>0 && p->iTable==iTable && p->iColumn==iColumn ){
+      p->lru = pParse->iCacheCnt++;
+      sqlite3ExprCachePinRegister(pParse, p->iReg);
       return p->iReg;
     }
   }  
   assert( v!=0 );
-  if( iColumn<0 ){
-    int op = (pTab && IsVirtual(pTab)) ? OP_VRowid : OP_Rowid;
-    sqlite3VdbeAddOp2(v, op, iTable, iReg);
-  }else if( pTab==0 ){
-    sqlite3VdbeAddOp3(v, OP_Column, iTable, iColumn, iReg);
-  }else{
-    int op = IsVirtual(pTab) ? OP_VColumn : OP_Column;
-    sqlite3VdbeAddOp3(v, op, iTable, iColumn, iReg);
-    sqlite3ColumnDefault(v, pTab, iColumn);
-#ifndef SQLITE_OMIT_FLOATING_POINT
-    if( pTab->aCol[iColumn].affinity==SQLITE_AFF_REAL ){
-      sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
-    }
-#endif
-  }
-  if( pParse->disableColCache==0 ){
-    i = pParse->iColCache;
-    p = &pParse->aColCache[i];
-    p->iTable = iTable;
-    p->iColumn = iColumn;
-    p->iReg = iReg;
-    p->affChange = 0;
-    i++;
-    if( i>=ArraySize(pParse->aColCache) ) i = 0;
-    if( i>pParse->nColCache ) pParse->nColCache = i;
-    pParse->iColCache = i;
+  sqlite3ExprCodeGetColumnOfTable(v, pTab, iTable, iColumn, iReg);
+  if( p5 ){
+    sqlite3VdbeChangeP5(v, p5);
+  }else{   
+    sqlite3ExprCacheStore(pParse, iTable, iColumn, iReg);
   }
   return iReg;
 }
 
 /*
-** Clear all column cache entries associated with the vdbe
-** cursor with cursor number iTable.
+** Clear all column cache entries.
 */
-SQLITE_PRIVATE void sqlite3ExprClearColumnCache(Parse *pParse, int iTable){
-  if( iTable<0 ){
-    pParse->nColCache = 0;
-    pParse->iColCache = 0;
-  }else{
-    int i;
-    for(i=0; i<pParse->nColCache; i++){
-      if( pParse->aColCache[i].iTable==iTable ){
-        testcase( i==pParse->nColCache-1 );
-        pParse->aColCache[i] = pParse->aColCache[--pParse->nColCache];
-        pParse->iColCache = pParse->nColCache;
-      }
+SQLITE_PRIVATE void sqlite3ExprCacheClear(Parse *pParse){
+  int i;
+  struct yColCache *p;
+
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    if( p->iReg ){
+      cacheEntryClear(pParse, p);
+      p->iReg = 0;
     }
   }
 }
@@ -57845,14 +75473,7 @@ SQLITE_PRIVATE void sqlite3ExprClearColumnCache(Parse *pParse, int iTable){
 ** registers starting with iStart.
 */
 SQLITE_PRIVATE void sqlite3ExprCacheAffinityChange(Parse *pParse, int iStart, int iCount){
-  int iEnd = iStart + iCount - 1;
-  int i;
-  for(i=0; i<pParse->nColCache; i++){
-    int r = pParse->aColCache[i].iReg;
-    if( r>=iStart && r<=iEnd ){
-      pParse->aColCache[i].affChange = 1;
-    }
-  }
+  sqlite3ExprCacheRemove(pParse, iStart, iCount);
 }
 
 /*
@@ -57861,12 +75482,13 @@ SQLITE_PRIVATE void sqlite3ExprCacheAffinityChange(Parse *pParse, int iStart, in
 */
 SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
   int i;
-  if( iFrom==iTo ) return;
+  struct yColCache *p;
+  if( NEVER(iFrom==iTo) ) return;
   sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
-  for(i=0; i<pParse->nColCache; i++){
-    int x = pParse->aColCache[i].iReg;
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    int x = p->iReg;
     if( x>=iFrom && x<iFrom+nReg ){
-      pParse->aColCache[i].iReg += iTo-iFrom;
+      p->iReg += iTo-iFrom;
     }
   }
 }
@@ -57877,105 +75499,30 @@ SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int n
 */
 SQLITE_PRIVATE void sqlite3ExprCodeCopy(Parse *pParse, int iFrom, int iTo, int nReg){
   int i;
-  if( iFrom==iTo ) return;
+  if( NEVER(iFrom==iTo) ) return;
   for(i=0; i<nReg; i++){
     sqlite3VdbeAddOp2(pParse->pVdbe, OP_Copy, iFrom+i, iTo+i);
   }
 }
 
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
 /*
 ** Return true if any register in the range iFrom..iTo (inclusive)
 ** is used as part of the column cache.
+**
+** This routine is used within assert() and testcase() macros only
+** and does not appear in a normal build.
 */
 static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
   int i;
-  for(i=0; i<pParse->nColCache; i++){
-    int r = pParse->aColCache[i].iReg;
-    if( r>=iFrom && r<=iTo ) return 1;
+  struct yColCache *p;
+  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+    int r = p->iReg;
+    if( r>=iFrom && r<=iTo ) return 1;    /*NO_TEST*/
   }
   return 0;
 }
-
-/*
-** There is a value in register iReg.
-**
-** We are going to modify the value, so we need to make sure it
-** is not a cached register.  If iReg is a cached register,
-** then clear the corresponding cache line.
-*/
-SQLITE_PRIVATE void sqlite3ExprWritableRegister(Parse *pParse, int iReg){
-  int i;
-  if( usedAsColumnCache(pParse, iReg, iReg) ){
-    for(i=0; i<pParse->nColCache; i++){
-      if( pParse->aColCache[i].iReg==iReg ){
-        pParse->aColCache[i] = pParse->aColCache[--pParse->nColCache];
-        pParse->iColCache = pParse->nColCache;
-      }
-    }
-  }
-}
-
-/*
-** If the last instruction coded is an ephemeral copy of any of
-** the registers in the nReg registers beginning with iReg, then
-** convert the last instruction from OP_SCopy to OP_Copy.
-*/
-SQLITE_PRIVATE void sqlite3ExprHardCopy(Parse *pParse, int iReg, int nReg){
-  int addr;
-  VdbeOp *pOp;
-  Vdbe *v;
-
-  v = pParse->pVdbe;
-  addr = sqlite3VdbeCurrentAddr(v);
-  pOp = sqlite3VdbeGetOp(v, addr-1);
-  assert( pOp || pParse->db->mallocFailed );
-  if( pOp && pOp->opcode==OP_SCopy && pOp->p1>=iReg && pOp->p1<iReg+nReg ){
-    pOp->opcode = OP_Copy;
-  }
-}
-
-/*
-** Generate code to store the value of the iAlias-th alias in register
-** target.  The first time this is called, pExpr is evaluated to compute
-** the value of the alias.  The value is stored in an auxiliary register
-** and the number of that register is returned.  On subsequent calls,
-** the register number is returned without generating any code.
-**
-** Note that in order for this to work, code must be generated in the
-** same order that it is executed.
-**
-** Aliases are numbered starting with 1.  So iAlias is in the range
-** of 1 to pParse->nAlias inclusive.  
-**
-** pParse->aAlias[iAlias-1] records the register number where the value
-** of the iAlias-th alias is stored.  If zero, that means that the
-** alias has not yet been computed.
-*/
-static int codeAlias(Parse *pParse, int iAlias, Expr *pExpr, int target){
-  sqlite3 *db = pParse->db;
-  int iReg;
-  if( pParse->nAliasAlloc<pParse->nAlias ){
-    pParse->aAlias = sqlite3DbReallocOrFree(db, pParse->aAlias,
-                                 sizeof(pParse->aAlias[0])*pParse->nAlias );
-    testcase( db->mallocFailed && pParse->nAliasAlloc>0 );
-    if( db->mallocFailed ) return 0;
-    memset(&pParse->aAlias[pParse->nAliasAlloc], 0,
-           (pParse->nAlias-pParse->nAliasAlloc)*sizeof(pParse->aAlias[0]));
-    pParse->nAliasAlloc = pParse->nAlias;
-  }
-  assert( iAlias>0 && iAlias<=pParse->nAlias );
-  iReg = pParse->aAlias[iAlias-1];
-  if( iReg==0 ){
-    if( pParse->disableColCache ){
-      iReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
-    }else{
-      iReg = ++pParse->nMem;
-      sqlite3ExprCode(pParse, pExpr, iReg);
-      pParse->aAlias[iAlias-1] = iReg;
-    }
-  }
-  return iReg;
-}
+#endif /* SQLITE_DEBUG || SQLITE_COVERAGE_TEST */
 
 /*
 ** Generate code into the current Vdbe to evaluate the given
@@ -57995,12 +75542,13 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
   int regFree1 = 0;         /* If non-zero free this temporary register */
   int regFree2 = 0;         /* If non-zero free this temporary register */
   int r1, r2, r3, r4;       /* Various register numbers */
-  sqlite3 *db;
+  sqlite3 *db = pParse->db; /* The database connection */
 
-  db = pParse->db;
-  assert( v!=0 || db->mallocFailed );
   assert( target>0 && target<=pParse->nMem );
-  if( v==0 ) return 0;
+  if( v==0 ){
+    assert( pParse->db->mallocFailed );
+    return 0;
+  }
 
   if( pExpr==0 ){
     op = TK_NULL;
@@ -58016,7 +75564,7 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
         inReg = pCol->iMem;
         break;
       }else if( pAggInfo->useSortingIdx ){
-        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdx,
+        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdxPTab,
                               pCol->iSorterColumn, target);
         break;
       }
@@ -58028,25 +75576,26 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
         assert( pParse->ckBase>0 );
         inReg = pExpr->iColumn + pParse->ckBase;
       }else{
-        testcase( (pExpr->flags & EP_AnyAff)!=0 );
         inReg = sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
                                  pExpr->iColumn, pExpr->iTable, target,
-                                 pExpr->flags & EP_AnyAff);
+                                 pExpr->op2);
       }
       break;
     }
     case TK_INTEGER: {
-      codeInteger(v, pExpr, 0, target);
+      codeInteger(pParse, pExpr, 0, target);
       break;
     }
+#ifndef SQLITE_OMIT_FLOATING_POINT
     case TK_FLOAT: {
-      codeReal(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      codeReal(v, pExpr->u.zToken, 0, target);
       break;
     }
+#endif
     case TK_STRING: {
-      sqlite3DequoteExpr(db, pExpr);
-      sqlite3VdbeAddOp4(v,OP_String8, 0, target, 0,
-                        (char*)pExpr->token.z, pExpr->token.n);
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3VdbeAddOp4(v, OP_String8, 0, target, 0, pExpr->u.zToken, 0);
       break;
     }
     case TK_NULL: {
@@ -58058,21 +75607,26 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       int n;
       const char *z;
       char *zBlob;
-      assert( pExpr->token.n>=3 );
-      assert( pExpr->token.z[0]=='x' || pExpr->token.z[0]=='X' );
-      assert( pExpr->token.z[1]=='\'' );
-      assert( pExpr->token.z[pExpr->token.n-1]=='\'' );
-      n = pExpr->token.n - 3;
-      z = (char*)pExpr->token.z + 2;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+      assert( pExpr->u.zToken[1]=='\'' );
+      z = &pExpr->u.zToken[2];
+      n = sqlite3Strlen30(z) - 1;
+      assert( z[n]=='\'' );
       zBlob = sqlite3HexToBlob(sqlite3VdbeDb(v), z, n);
       sqlite3VdbeAddOp4(v, OP_Blob, n/2, target, 0, zBlob, P4_DYNAMIC);
       break;
     }
 #endif
     case TK_VARIABLE: {
-      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iTable, target);
-      if( pExpr->token.n>1 ){
-        sqlite3VdbeChangeP4(v, -1, (char*)pExpr->token.z, pExpr->token.n);
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken!=0 );
+      assert( pExpr->u.zToken[0]!=0 );
+      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
+      if( pExpr->u.zToken[1]!=0 ){
+        assert( pExpr->u.zToken[0]=='?' 
+             || strcmp(pExpr->u.zToken, pParse->azVar[pExpr->iColumn-1])==0 );
+        sqlite3VdbeChangeP4(v, -1, pParse->azVar[pExpr->iColumn-1], P4_STATIC);
       }
       break;
     }
@@ -58081,7 +75635,7 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       break;
     }
     case TK_AS: {
-      inReg = codeAlias(pParse, pExpr->iTable, pExpr->pLeft, target);
+      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
       break;
     }
 #ifndef SQLITE_OMIT_CAST
@@ -58089,7 +75643,8 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       /* Expressions of the form:   CAST(pLeft AS token) */
       int aff, to_op;
       inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
-      aff = sqlite3AffinityType(&pExpr->token);
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      aff = sqlite3AffinityType(pExpr->u.zToken);
       to_op = aff - SQLITE_AFF_TEXT + OP_ToText;
       assert( to_op==OP_ToText    || aff!=SQLITE_AFF_TEXT    );
       assert( to_op==OP_ToBlob    || aff!=SQLITE_AFF_NONE    );
@@ -58129,14 +75684,27 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       testcase( op==TK_GE );
       testcase( op==TK_EQ );
       testcase( op==TK_NE );
-      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
-                                  pExpr->pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                   r1, r2, inReg, SQLITE_STOREP2);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       break;
     }
+    case TK_IS:
+    case TK_ISNOT: {
+      testcase( op==TK_IS );
+      testcase( op==TK_ISNOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, inReg, SQLITE_STOREP2 | SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
     case TK_AND:
     case TK_OR:
     case TK_PLUS:
@@ -58181,12 +75749,13 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
     case TK_UMINUS: {
       Expr *pLeft = pExpr->pLeft;
       assert( pLeft );
-      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
-        if( pLeft->op==TK_FLOAT ){
-          codeReal(v, (char*)pLeft->token.z, pLeft->token.n, 1, target);
-        }else{
-          codeInteger(v, pLeft, 1, target);
-        }
+      if( pLeft->op==TK_INTEGER ){
+        codeInteger(pParse, pLeft, 1, target);
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      }else if( pLeft->op==TK_FLOAT ){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        codeReal(v, pLeft->u.zToken, 1, target);
+#endif
       }else{
         regFree1 = r1 = sqlite3GetTempReg(pParse);
         sqlite3VdbeAddOp2(v, OP_Integer, 0, r1);
@@ -58227,8 +75796,8 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
     case TK_AGG_FUNCTION: {
       AggInfo *pInfo = pExpr->pAggInfo;
       if( pInfo==0 ){
-        sqlite3ErrorMsg(pParse, "misuse of aggregate: %T",
-            &pExpr->span);
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        sqlite3ErrorMsg(pParse, "misuse of aggregate: %s()", pExpr->u.zToken);
       }else{
         inReg = pInfo->aFunc[pExpr->iAgg].iMem;
       }
@@ -58236,28 +75805,80 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
     }
     case TK_CONST_FUNC:
     case TK_FUNCTION: {
-      ExprList *pList = pExpr->pList;
-      int nExpr = pList ? pList->nExpr : 0;
-      FuncDef *pDef;
-      int nId;
-      const char *zId;
-      int constMask = 0;
-      int i;
-      u8 enc = ENC(db);
-      CollSeq *pColl = 0;
+      ExprList *pFarg;       /* List of function arguments */
+      int nFarg;             /* Number of function arguments */
+      FuncDef *pDef;         /* The function definition object */
+      int nId;               /* Length of the function name in bytes */
+      const char *zId;       /* The function name */
+      int constMask = 0;     /* Mask of function arguments that are constant */
+      int i;                 /* Loop counter */
+      u8 enc = ENC(db);      /* The text encoding used by this database */
+      CollSeq *pColl = 0;    /* A collating sequence */
 
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
       testcase( op==TK_CONST_FUNC );
       testcase( op==TK_FUNCTION );
-      zId = (char*)pExpr->token.z;
-      nId = pExpr->token.n;
-      pDef = sqlite3FindFunction(db, zId, nId, nExpr, enc, 0);
-      assert( pDef!=0 );
-      if( pList ){
-        nExpr = pList->nExpr;
-        r1 = sqlite3GetTempRange(pParse, nExpr);
-        sqlite3ExprCodeExprList(pParse, pList, r1, 1);
+      if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ){
+        pFarg = 0;
       }else{
-        nExpr = r1 = 0;
+        pFarg = pExpr->x.pList;
+      }
+      nFarg = pFarg ? pFarg->nExpr : 0;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      zId = pExpr->u.zToken;
+      nId = sqlite3Strlen30(zId);
+      pDef = sqlite3FindFunction(db, zId, nId, nFarg, enc, 0);
+      if( pDef==0 ){
+        sqlite3ErrorMsg(pParse, "unknown function: %.*s()", nId, zId);
+        break;
+      }
+
+      /* Attempt a direct implementation of the built-in COALESCE() and
+      ** IFNULL() functions.  This avoids unnecessary evalation of
+      ** arguments past the first non-NULL argument.
+      */
+      if( pDef->flags & SQLITE_FUNC_COALESCE ){
+        int endCoalesce = sqlite3VdbeMakeLabel(v);
+        assert( nFarg>=2 );
+        sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
+        for(i=1; i<nFarg; i++){
+          sqlite3VdbeAddOp2(v, OP_NotNull, target, endCoalesce);
+          sqlite3ExprCacheRemove(pParse, target, 1);
+          sqlite3ExprCachePush(pParse);
+          sqlite3ExprCode(pParse, pFarg->a[i].pExpr, target);
+          sqlite3ExprCachePop(pParse, 1);
+        }
+        sqlite3VdbeResolveLabel(v, endCoalesce);
+        break;
+      }
+
+
+      if( pFarg ){
+        r1 = sqlite3GetTempRange(pParse, nFarg);
+
+        /* For length() and typeof() functions with a column argument,
+        ** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
+        ** or OPFLAG_TYPEOFARG respectively, to avoid unnecessary data
+        ** loading.
+        */
+        if( (pDef->flags & (SQLITE_FUNC_LENGTH|SQLITE_FUNC_TYPEOF))!=0 ){
+          u8 exprOp;
+          assert( nFarg==1 );
+          assert( pFarg->a[0].pExpr!=0 );
+          exprOp = pFarg->a[0].pExpr->op;
+          if( exprOp==TK_COLUMN || exprOp==TK_AGG_COLUMN ){
+            assert( SQLITE_FUNC_LENGTH==OPFLAG_LENGTHARG );
+            assert( SQLITE_FUNC_TYPEOF==OPFLAG_TYPEOFARG );
+            testcase( pDef->flags==SQLITE_FUNC_LENGTH );
+            pFarg->a[0].pExpr->op2 = pDef->flags;
+          }
+        }
+
+        sqlite3ExprCachePush(pParse);     /* Ticket 2ea2425d34be */
+        sqlite3ExprCodeExprList(pParse, pFarg, r1, 1);
+        sqlite3ExprCachePop(pParse, 1);   /* Ticket 2ea2425d34be */
+      }else{
+        r1 = 0;
       }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
       /* Possibly overload the function if the first argument is
@@ -58272,18 +75893,18 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       ** "glob(B,A).  We want to use the A in "A glob B" to test
       ** for function overloading.  But we use the B term in "glob(B,A)".
       */
-      if( nExpr>=2 && (pExpr->flags & EP_InfixFunc) ){
-        pDef = sqlite3VtabOverloadFunction(db, pDef, nExpr, pList->a[1].pExpr);
-      }else if( nExpr>0 ){
-        pDef = sqlite3VtabOverloadFunction(db, pDef, nExpr, pList->a[0].pExpr);
+      if( nFarg>=2 && (pExpr->flags & EP_InfixFunc) ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[1].pExpr);
+      }else if( nFarg>0 ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
       }
 #endif
-      for(i=0; i<nExpr && i<32; i++){
-        if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
+      for(i=0; i<nFarg; i++){
+        if( i<32 && sqlite3ExprIsConstant(pFarg->a[i].pExpr) ){
           constMask |= (1<<i);
         }
         if( (pDef->flags & SQLITE_FUNC_NEEDCOLL)!=0 && !pColl ){
-          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
+          pColl = sqlite3ExprCollSeq(pParse, pFarg->a[i].pExpr);
         }
       }
       if( pDef->flags & SQLITE_FUNC_NEEDCOLL ){
@@ -58292,11 +75913,10 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       }
       sqlite3VdbeAddOp4(v, OP_Function, constMask, r1, target,
                         (char*)pDef, P4_FUNCDEF);
-      sqlite3VdbeChangeP5(v, (u8)nExpr);
-      if( nExpr ){
-        sqlite3ReleaseTempRange(pParse, r1, nExpr);
+      sqlite3VdbeChangeP5(v, (u8)nFarg);
+      if( nFarg ){
+        sqlite3ReleaseTempRange(pParse, r1, nFarg);
       }
-      sqlite3ExprCacheAffinityChange(pParse, r1, nExpr);
       break;
     }
 #ifndef SQLITE_OMIT_SUBQUERY
@@ -58304,102 +75924,23 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
     case TK_SELECT: {
       testcase( op==TK_EXISTS );
       testcase( op==TK_SELECT );
-      if( pExpr->iColumn==0 ){
-        sqlite3CodeSubselect(pParse, pExpr, 0, 0);
-      }
-      inReg = pExpr->iColumn;
+      inReg = sqlite3CodeSubselect(pParse, pExpr, 0, 0);
       break;
     }
     case TK_IN: {
-      int rNotFound = 0;
-      int rMayHaveNull = 0;
-      int j2, j3, j4, j5;
-      char affinity;
-      int eType;
-
-      VdbeNoopComment((v, "begin IN expr r%d", target));
-      eType = sqlite3FindInIndex(pParse, pExpr, &rMayHaveNull);
-      if( rMayHaveNull ){
-        rNotFound = ++pParse->nMem;
-      }
-
-      /* Figure out the affinity to use to create a key from the results
-      ** of the expression. affinityStr stores a static string suitable for
-      ** P4 of OP_MakeRecord.
-      */
-      affinity = comparisonAffinity(pExpr);
-
-
-      /* Code the <expr> from "<expr> IN (...)". The temporary table
-      ** pExpr->iTable contains the values that make up the (...) set.
-      */
-      pParse->disableColCache++;
-      sqlite3ExprCode(pParse, pExpr->pLeft, target);
-      pParse->disableColCache--;
-      j2 = sqlite3VdbeAddOp1(v, OP_IsNull, target);
-      if( eType==IN_INDEX_ROWID ){
-        j3 = sqlite3VdbeAddOp1(v, OP_MustBeInt, target);
-        j4 = sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, 0, target);
-        sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
-        j5 = sqlite3VdbeAddOp0(v, OP_Goto);
-        sqlite3VdbeJumpHere(v, j3);
-        sqlite3VdbeJumpHere(v, j4);
-        sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
-      }else{
-        r2 = regFree2 = sqlite3GetTempReg(pParse);
-
-        /* Create a record and test for set membership. If the set contains
-        ** the value, then jump to the end of the test code. The target
-        ** register still contains the true (1) value written to it earlier.
-        */
-        sqlite3VdbeAddOp4(v, OP_MakeRecord, target, 1, r2, &affinity, 1);
-        sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
-        j5 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, r2);
-
-        /* If the set membership test fails, then the result of the 
-        ** "x IN (...)" expression must be either 0 or NULL. If the set
-        ** contains no NULL values, then the result is 0. If the set 
-        ** contains one or more NULL values, then the result of the
-        ** expression is also NULL.
-        */
-        if( rNotFound==0 ){
-          /* This branch runs if it is known at compile time (now) that 
-          ** the set contains no NULL values. This happens as the result
-          ** of a "NOT NULL" constraint in the database schema. No need
-          ** to test the data structure at runtime in this case.
-          */
-          sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
-        }else{
-          /* This block populates the rNotFound register with either NULL
-          ** or 0 (an integer value). If the data structure contains one
-          ** or more NULLs, then set rNotFound to NULL. Otherwise, set it
-          ** to 0. If register rMayHaveNull is already set to some value
-          ** other than NULL, then the test has already been run and 
-          ** rNotFound is already populated.
-          */
-          static const char nullRecord[] = { 0x02, 0x00 };
-          j3 = sqlite3VdbeAddOp1(v, OP_NotNull, rMayHaveNull);
-          sqlite3VdbeAddOp2(v, OP_Null, 0, rNotFound);
-          sqlite3VdbeAddOp4(v, OP_Blob, 2, rMayHaveNull, 0, 
-                             nullRecord, P4_STATIC);
-          j4 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, rMayHaveNull);
-          sqlite3VdbeAddOp2(v, OP_Integer, 0, rNotFound);
-          sqlite3VdbeJumpHere(v, j4);
-          sqlite3VdbeJumpHere(v, j3);
-
-          /* Copy the value of register rNotFound (which is either NULL or 0)
-          ** into the target register. This will be the result of the
-          ** expression.
-          */
-          sqlite3VdbeAddOp2(v, OP_Copy, rNotFound, target);
-        }
-      }
-      sqlite3VdbeJumpHere(v, j2);
-      sqlite3VdbeJumpHere(v, j5);
-      VdbeComment((v, "end IN expr r%d", target));
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = sqlite3VdbeMakeLabel(v);
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, 0);
+      sqlite3VdbeResolveLabel(v, destIfNull);
       break;
     }
-#endif
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+
     /*
     **    x BETWEEN y AND z
     **
@@ -58413,11 +75954,11 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
     */
     case TK_BETWEEN: {
       Expr *pLeft = pExpr->pLeft;
-      struct ExprList_item *pLItem = pExpr->pList->a;
+      struct ExprList_item *pLItem = pExpr->x.pList->a;
       Expr *pRight = pLItem->pExpr;
 
-      codeCompareOperands(pParse, pLeft, &r1, &regFree1,
-                                  pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       r3 = sqlite3GetTempReg(pParse);
@@ -58440,6 +75981,60 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       break;
     }
 
+    case TK_TRIGGER: {
+      /* If the opcode is TK_TRIGGER, then the expression is a reference
+      ** to a column in the new.* or old.* pseudo-tables available to
+      ** trigger programs. In this case Expr.iTable is set to 1 for the
+      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
+      ** is set to the column of the pseudo-table to read, or to -1 to
+      ** read the rowid field.
+      **
+      ** The expression is implemented using an OP_Param opcode. The p1
+      ** parameter is set to 0 for an old.rowid reference, or to (i+1)
+      ** to reference another column of the old.* pseudo-table, where 
+      ** i is the index of the column. For a new.rowid reference, p1 is
+      ** set to (n+1), where n is the number of columns in each pseudo-table.
+      ** For a reference to any other column in the new.* pseudo-table, p1
+      ** is set to (n+2+i), where n and i are as defined previously. For
+      ** example, if the table on which triggers are being fired is
+      ** declared as:
+      **
+      **   CREATE TABLE t1(a, b);
+      **
+      ** Then p1 is interpreted as follows:
+      **
+      **   p1==0   ->    old.rowid     p1==3   ->    new.rowid
+      **   p1==1   ->    old.a         p1==4   ->    new.a
+      **   p1==2   ->    old.b         p1==5   ->    new.b       
+      */
+      Table *pTab = pExpr->pTab;
+      int p1 = pExpr->iTable * (pTab->nCol+1) + 1 + pExpr->iColumn;
+
+      assert( pExpr->iTable==0 || pExpr->iTable==1 );
+      assert( pExpr->iColumn>=-1 && pExpr->iColumn<pTab->nCol );
+      assert( pTab->iPKey<0 || pExpr->iColumn!=pTab->iPKey );
+      assert( p1>=0 && p1<(pTab->nCol*2+2) );
+
+      sqlite3VdbeAddOp2(v, OP_Param, p1, target);
+      VdbeComment((v, "%s.%s -> $%d",
+        (pExpr->iTable ? "new" : "old"),
+        (pExpr->iColumn<0 ? "rowid" : pExpr->pTab->aCol[pExpr->iColumn].zName),
+        target
+      ));
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      /* If the column has REAL affinity, it may currently be stored as an
+      ** integer. Use OP_RealAffinity to make sure it is really real.  */
+      if( pExpr->iColumn>=0 
+       && pTab->aCol[pExpr->iColumn].affinity==SQLITE_AFF_REAL
+      ){
+        sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+      }
+#endif
+      break;
+    }
+
+
     /*
     ** Form A:
     **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
@@ -58461,7 +76056,7 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
     ** or if there is no matching Ei, the ELSE term Y, or if there is
     ** no ELSE term, NULL.
     */
-    case TK_CASE: {
+    default: assert( op==TK_CASE ); {
       int endLabel;                     /* GOTO label for end of CASE stmt */
       int nextCase;                     /* GOTO label for next WHEN clause */
       int nExpr;                        /* 2x number of WHEN terms */
@@ -58472,26 +76067,33 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
       Expr cacheX;                      /* Cached expression X */
       Expr *pX;                         /* The X expression */
       Expr *pTest = 0;                  /* X==Ei (form A) or just Ei (form B) */
+      VVA_ONLY( int iCacheLevel = pParse->iCacheLevel; )
 
-      assert(pExpr->pList);
-      assert((pExpr->pList->nExpr % 2) == 0);
-      assert(pExpr->pList->nExpr > 0);
-      pEList = pExpr->pList;
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) && pExpr->x.pList );
+      assert((pExpr->x.pList->nExpr % 2) == 0);
+      assert(pExpr->x.pList->nExpr > 0);
+      pEList = pExpr->x.pList;
       aListelem = pEList->a;
       nExpr = pEList->nExpr;
       endLabel = sqlite3VdbeMakeLabel(v);
       if( (pX = pExpr->pLeft)!=0 ){
         cacheX = *pX;
-        testcase( pX->op==TK_COLUMN || pX->op==TK_REGISTER );
+        testcase( pX->op==TK_COLUMN );
+        testcase( pX->op==TK_REGISTER );
         cacheX.iTable = sqlite3ExprCodeTemp(pParse, pX, &regFree1);
         testcase( regFree1==0 );
         cacheX.op = TK_REGISTER;
         opCompare.op = TK_EQ;
         opCompare.pLeft = &cacheX;
         pTest = &opCompare;
+        /* Ticket b351d95f9cd5ef17e9d9dbae18f5ca8611190001:
+        ** The value in regFree1 might get SCopy-ed into the file result.
+        ** So make sure that the regFree1 register is not reused for other
+        ** purposes and possibly overwritten.  */
+        regFree1 = 0;
       }
-      pParse->disableColCache++;
       for(i=0; i<nExpr; i=i+2){
+        sqlite3ExprCachePush(pParse);
         if( pX ){
           assert( pTest!=0 );
           opCompare.pRight = aListelem[i].pExpr;
@@ -58499,44 +76101,50 @@ SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target)
           pTest = aListelem[i].pExpr;
         }
         nextCase = sqlite3VdbeMakeLabel(v);
-        testcase( pTest->op==TK_COLUMN || pTest->op==TK_REGISTER );
+        testcase( pTest->op==TK_COLUMN );
         sqlite3ExprIfFalse(pParse, pTest, nextCase, SQLITE_JUMPIFNULL);
         testcase( aListelem[i+1].pExpr->op==TK_COLUMN );
         testcase( aListelem[i+1].pExpr->op==TK_REGISTER );
         sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
         sqlite3VdbeAddOp2(v, OP_Goto, 0, endLabel);
+        sqlite3ExprCachePop(pParse, 1);
         sqlite3VdbeResolveLabel(v, nextCase);
       }
       if( pExpr->pRight ){
+        sqlite3ExprCachePush(pParse);
         sqlite3ExprCode(pParse, pExpr->pRight, target);
+        sqlite3ExprCachePop(pParse, 1);
       }else{
         sqlite3VdbeAddOp2(v, OP_Null, 0, target);
       }
+      assert( db->mallocFailed || pParse->nErr>0 
+           || pParse->iCacheLevel==iCacheLevel );
       sqlite3VdbeResolveLabel(v, endLabel);
-      assert( pParse->disableColCache>0 );
-      pParse->disableColCache--;
       break;
     }
 #ifndef SQLITE_OMIT_TRIGGER
     case TK_RAISE: {
-      if( !pParse->trigStack ){
+      assert( pExpr->affinity==OE_Rollback 
+           || pExpr->affinity==OE_Abort
+           || pExpr->affinity==OE_Fail
+           || pExpr->affinity==OE_Ignore
+      );
+      if( !pParse->pTriggerTab ){
         sqlite3ErrorMsg(pParse,
                        "RAISE() may only be used within a trigger-program");
         return 0;
       }
-      if( pExpr->iColumn!=OE_Ignore ){
-         assert( pExpr->iColumn==OE_Rollback ||
-                 pExpr->iColumn == OE_Abort ||
-                 pExpr->iColumn == OE_Fail );
-         sqlite3DequoteExpr(db, pExpr);
-         sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn, 0,
-                        (char*)pExpr->token.z, pExpr->token.n);
-      } else {
-         assert( pExpr->iColumn == OE_Ignore );
-         sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0);
-         sqlite3VdbeAddOp2(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
-         VdbeComment((v, "raise(IGNORE)"));
+      if( pExpr->affinity==OE_Abort ){
+        sqlite3MayAbort(pParse);
       }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      if( pExpr->affinity==OE_Ignore ){
+        sqlite3VdbeAddOp4(
+            v, OP_Halt, SQLITE_OK, OE_Ignore, 0, pExpr->u.zToken,0);
+      }else{
+        sqlite3HaltConstraint(pParse, pExpr->affinity, pExpr->u.zToken, 0);
+      }
+
       break;
     }
 #endif
@@ -58576,10 +76184,14 @@ SQLITE_PRIVATE int sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
   int inReg;
 
   assert( target>0 && target<=pParse->nMem );
-  inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
-  assert( pParse->pVdbe || pParse->db->mallocFailed );
-  if( inReg!=target && pParse->pVdbe ){
-    sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, inReg, target);
+  if( pExpr && pExpr->op==TK_REGISTER ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_Copy, pExpr->iTable, target);
+  }else{
+    inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
+    assert( pParse->pVdbe || pParse->db->mallocFailed );
+    if( inReg!=target && pParse->pVdbe ){
+      sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, inReg, target);
+    }
   }
   return target;
 }
@@ -58601,16 +76213,284 @@ SQLITE_PRIVATE int sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int targe
   int inReg;
   inReg = sqlite3ExprCode(pParse, pExpr, target);
   assert( target>0 );
-  if( pExpr->op!=TK_REGISTER ){  
+  /* This routine is called for terms to INSERT or UPDATE.  And the only
+  ** other place where expressions can be converted into TK_REGISTER is
+  ** in WHERE clause processing.  So as currently implemented, there is
+  ** no way for a TK_REGISTER to exist here.  But it seems prudent to
+  ** keep the ALWAYS() in case the conditions above change with future
+  ** modifications or enhancements. */
+  if( ALWAYS(pExpr->op!=TK_REGISTER) ){  
     int iMem;
     iMem = ++pParse->nMem;
     sqlite3VdbeAddOp2(v, OP_Copy, inReg, iMem);
     pExpr->iTable = iMem;
+    pExpr->op2 = pExpr->op;
     pExpr->op = TK_REGISTER;
   }
   return inReg;
 }
 
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
+/*
+** Generate a human-readable explanation of an expression tree.
+*/
+SQLITE_PRIVATE void sqlite3ExplainExpr(Vdbe *pOut, Expr *pExpr){
+  int op;                   /* The opcode being coded */
+  const char *zBinOp = 0;   /* Binary operator */
+  const char *zUniOp = 0;   /* Unary operator */
+  if( pExpr==0 ){
+    op = TK_NULL;
+  }else{
+    op = pExpr->op;
+  }
+  switch( op ){
+    case TK_AGG_COLUMN: {
+      sqlite3ExplainPrintf(pOut, "AGG{%d:%d}",
+            pExpr->iTable, pExpr->iColumn);
+      break;
+    }
+    case TK_COLUMN: {
+      if( pExpr->iTable<0 ){
+        /* This only happens when coding check constraints */
+        sqlite3ExplainPrintf(pOut, "COLUMN(%d)", pExpr->iColumn);
+      }else{
+        sqlite3ExplainPrintf(pOut, "{%d:%d}",
+                             pExpr->iTable, pExpr->iColumn);
+      }
+      break;
+    }
+    case TK_INTEGER: {
+      if( pExpr->flags & EP_IntValue ){
+        sqlite3ExplainPrintf(pOut, "%d", pExpr->u.iValue);
+      }else{
+        sqlite3ExplainPrintf(pOut, "%s", pExpr->u.zToken);
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    case TK_FLOAT: {
+      sqlite3ExplainPrintf(pOut,"%s", pExpr->u.zToken);
+      break;
+    }
+#endif
+    case TK_STRING: {
+      sqlite3ExplainPrintf(pOut,"%Q", pExpr->u.zToken);
+      break;
+    }
+    case TK_NULL: {
+      sqlite3ExplainPrintf(pOut,"NULL");
+      break;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      sqlite3ExplainPrintf(pOut,"%s", pExpr->u.zToken);
+      break;
+    }
+#endif
+    case TK_VARIABLE: {
+      sqlite3ExplainPrintf(pOut,"VARIABLE(%s,%d)",
+                           pExpr->u.zToken, pExpr->iColumn);
+      break;
+    }
+    case TK_REGISTER: {
+      sqlite3ExplainPrintf(pOut,"REGISTER(%d)", pExpr->iTable);
+      break;
+    }
+    case TK_AS: {
+      sqlite3ExplainExpr(pOut, pExpr->pLeft);
+      break;
+    }
+#ifndef SQLITE_OMIT_CAST
+    case TK_CAST: {
+      /* Expressions of the form:   CAST(pLeft AS token) */
+      const char *zAff = "unk";
+      switch( sqlite3AffinityType(pExpr->u.zToken) ){
+        case SQLITE_AFF_TEXT:    zAff = "TEXT";     break;
+        case SQLITE_AFF_NONE:    zAff = "NONE";     break;
+        case SQLITE_AFF_NUMERIC: zAff = "NUMERIC";  break;
+        case SQLITE_AFF_INTEGER: zAff = "INTEGER";  break;
+        case SQLITE_AFF_REAL:    zAff = "REAL";     break;
+      }
+      sqlite3ExplainPrintf(pOut, "CAST-%s(", zAff);
+      sqlite3ExplainExpr(pOut, pExpr->pLeft);
+      sqlite3ExplainPrintf(pOut, ")");
+      break;
+    }
+#endif /* SQLITE_OMIT_CAST */
+    case TK_LT:      zBinOp = "LT";     break;
+    case TK_LE:      zBinOp = "LE";     break;
+    case TK_GT:      zBinOp = "GT";     break;
+    case TK_GE:      zBinOp = "GE";     break;
+    case TK_NE:      zBinOp = "NE";     break;
+    case TK_EQ:      zBinOp = "EQ";     break;
+    case TK_IS:      zBinOp = "IS";     break;
+    case TK_ISNOT:   zBinOp = "ISNOT";  break;
+    case TK_AND:     zBinOp = "AND";    break;
+    case TK_OR:      zBinOp = "OR";     break;
+    case TK_PLUS:    zBinOp = "ADD";    break;
+    case TK_STAR:    zBinOp = "MUL";    break;
+    case TK_MINUS:   zBinOp = "SUB";    break;
+    case TK_REM:     zBinOp = "REM";    break;
+    case TK_BITAND:  zBinOp = "BITAND"; break;
+    case TK_BITOR:   zBinOp = "BITOR";  break;
+    case TK_SLASH:   zBinOp = "DIV";    break;
+    case TK_LSHIFT:  zBinOp = "LSHIFT"; break;
+    case TK_RSHIFT:  zBinOp = "RSHIFT"; break;
+    case TK_CONCAT:  zBinOp = "CONCAT"; break;
+
+    case TK_UMINUS:  zUniOp = "UMINUS"; break;
+    case TK_UPLUS:   zUniOp = "UPLUS";  break;
+    case TK_BITNOT:  zUniOp = "BITNOT"; break;
+    case TK_NOT:     zUniOp = "NOT";    break;
+    case TK_ISNULL:  zUniOp = "ISNULL"; break;
+    case TK_NOTNULL: zUniOp = "NOTNULL"; break;
+
+    case TK_AGG_FUNCTION:
+    case TK_CONST_FUNC:
+    case TK_FUNCTION: {
+      ExprList *pFarg;       /* List of function arguments */
+      if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ){
+        pFarg = 0;
+      }else{
+        pFarg = pExpr->x.pList;
+      }
+      if( op==TK_AGG_FUNCTION ){
+        sqlite3ExplainPrintf(pOut, "AGG_FUNCTION%d:%s(",
+                             pExpr->op2, pExpr->u.zToken);
+      }else{
+        sqlite3ExplainPrintf(pOut, "FUNCTION:%s(", pExpr->u.zToken);
+      }
+      if( pFarg ){
+        sqlite3ExplainExprList(pOut, pFarg);
+      }
+      sqlite3ExplainPrintf(pOut, ")");
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS: {
+      sqlite3ExplainPrintf(pOut, "EXISTS(");
+      sqlite3ExplainSelect(pOut, pExpr->x.pSelect);
+      sqlite3ExplainPrintf(pOut,")");
+      break;
+    }
+    case TK_SELECT: {
+      sqlite3ExplainPrintf(pOut, "(");
+      sqlite3ExplainSelect(pOut, pExpr->x.pSelect);
+      sqlite3ExplainPrintf(pOut, ")");
+      break;
+    }
+    case TK_IN: {
+      sqlite3ExplainPrintf(pOut, "IN(");
+      sqlite3ExplainExpr(pOut, pExpr->pLeft);
+      sqlite3ExplainPrintf(pOut, ",");
+      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+        sqlite3ExplainSelect(pOut, pExpr->x.pSelect);
+      }else{
+        sqlite3ExplainExprList(pOut, pExpr->x.pList);
+      }
+      sqlite3ExplainPrintf(pOut, ")");
+      break;
+    }
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+    /*
+    **    x BETWEEN y AND z
+    **
+    ** This is equivalent to
+    **
+    **    x>=y AND x<=z
+    **
+    ** X is stored in pExpr->pLeft.
+    ** Y is stored in pExpr->pList->a[0].pExpr.
+    ** Z is stored in pExpr->pList->a[1].pExpr.
+    */
+    case TK_BETWEEN: {
+      Expr *pX = pExpr->pLeft;
+      Expr *pY = pExpr->x.pList->a[0].pExpr;
+      Expr *pZ = pExpr->x.pList->a[1].pExpr;
+      sqlite3ExplainPrintf(pOut, "BETWEEN(");
+      sqlite3ExplainExpr(pOut, pX);
+      sqlite3ExplainPrintf(pOut, ",");
+      sqlite3ExplainExpr(pOut, pY);
+      sqlite3ExplainPrintf(pOut, ",");
+      sqlite3ExplainExpr(pOut, pZ);
+      sqlite3ExplainPrintf(pOut, ")");
+      break;
+    }
+    case TK_TRIGGER: {
+      /* If the opcode is TK_TRIGGER, then the expression is a reference
+      ** to a column in the new.* or old.* pseudo-tables available to
+      ** trigger programs. In this case Expr.iTable is set to 1 for the
+      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
+      ** is set to the column of the pseudo-table to read, or to -1 to
+      ** read the rowid field.
+      */
+      sqlite3ExplainPrintf(pOut, "%s(%d)", 
+          pExpr->iTable ? "NEW" : "OLD", pExpr->iColumn);
+      break;
+    }
+    case TK_CASE: {
+      sqlite3ExplainPrintf(pOut, "CASE(");
+      sqlite3ExplainExpr(pOut, pExpr->pLeft);
+      sqlite3ExplainPrintf(pOut, ",");
+      sqlite3ExplainExprList(pOut, pExpr->x.pList);
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      const char *zType = "unk";
+      switch( pExpr->affinity ){
+        case OE_Rollback:   zType = "rollback";  break;
+        case OE_Abort:      zType = "abort";     break;
+        case OE_Fail:       zType = "fail";      break;
+        case OE_Ignore:     zType = "ignore";    break;
+      }
+      sqlite3ExplainPrintf(pOut, "RAISE-%s(%s)", zType, pExpr->u.zToken);
+      break;
+    }
+#endif
+  }
+  if( zBinOp ){
+    sqlite3ExplainPrintf(pOut,"%s(", zBinOp);
+    sqlite3ExplainExpr(pOut, pExpr->pLeft);
+    sqlite3ExplainPrintf(pOut,",");
+    sqlite3ExplainExpr(pOut, pExpr->pRight);
+    sqlite3ExplainPrintf(pOut,")");
+  }else if( zUniOp ){
+    sqlite3ExplainPrintf(pOut,"%s(", zUniOp);
+    sqlite3ExplainExpr(pOut, pExpr->pLeft);
+    sqlite3ExplainPrintf(pOut,")");
+  }
+}
+#endif /* defined(SQLITE_ENABLE_TREE_EXPLAIN) */
+
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
+/*
+** Generate a human-readable explanation of an expression list.
+*/
+SQLITE_PRIVATE void sqlite3ExplainExprList(Vdbe *pOut, ExprList *pList){
+  int i;
+  if( pList==0 || pList->nExpr==0 ){
+    sqlite3ExplainPrintf(pOut, "(empty-list)");
+    return;
+  }else if( pList->nExpr==1 ){
+    sqlite3ExplainExpr(pOut, pList->a[0].pExpr);
+  }else{
+    sqlite3ExplainPush(pOut);
+    for(i=0; i<pList->nExpr; i++){
+      sqlite3ExplainPrintf(pOut, "item[%d] = ", i);
+      sqlite3ExplainPush(pOut);
+      sqlite3ExplainExpr(pOut, pList->a[i].pExpr);
+      sqlite3ExplainPop(pOut);
+      if( i<pList->nExpr-1 ){
+        sqlite3ExplainNL(pOut);
+      }
+    }
+    sqlite3ExplainPop(pOut);
+  }
+}
+#endif /* SQLITE_DEBUG */
+
 /*
 ** Return TRUE if pExpr is an constant expression that is appropriate
 ** for factoring out of a loop.  Appropriate expressions are:
@@ -58658,10 +76538,10 @@ static int isAppropriateForFactoring(Expr *p){
       return 0;
     }
     case TK_UMINUS: {
-       if( p->pLeft->op==TK_FLOAT || p->pLeft->op==TK_INTEGER ){
-         return 0;
-       }
-       break;
+      if( p->pLeft->op==TK_FLOAT || p->pLeft->op==TK_INTEGER ){
+        return 0;
+      }
+      break;
     }
     default: {
       break;
@@ -58679,8 +76559,9 @@ static int isAppropriateForFactoring(Expr *p){
 static int evalConstExpr(Walker *pWalker, Expr *pExpr){
   Parse *pParse = pWalker->pParse;
   switch( pExpr->op ){
+    case TK_IN:
     case TK_REGISTER: {
-      return 1;
+      return WRC_Prune;
     }
     case TK_FUNCTION:
     case TK_AGG_FUNCTION:
@@ -58689,12 +76570,13 @@ static int evalConstExpr(Walker *pWalker, Expr *pExpr){
       ** Mark them this way to avoid generated unneeded OP_SCopy
       ** instructions. 
       */
-      ExprList *pList = pExpr->pList;
+      ExprList *pList = pExpr->x.pList;
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
       if( pList ){
         int i = pList->nExpr;
         struct ExprList_item *pItem = pList->a;
         for(; i>0; i--, pItem++){
-          if( pItem->pExpr ) pItem->pExpr->flags |= EP_FixedDest;
+          if( ALWAYS(pItem->pExpr) ) pItem->pExpr->flags |= EP_FixedDest;
         }
       }
       break;
@@ -58704,7 +76586,8 @@ static int evalConstExpr(Walker *pWalker, Expr *pExpr){
     int r1 = ++pParse->nMem;
     int r2;
     r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
-    if( r1!=r2 ) sqlite3ReleaseTempReg(pParse, r1);
+    if( NEVER(r1!=r2) ) sqlite3ReleaseTempReg(pParse, r1);
+    pExpr->op2 = pExpr->op;
     pExpr->op = TK_REGISTER;
     pExpr->iTable = r2;
     return WRC_Prune;
@@ -58716,9 +76599,22 @@ static int evalConstExpr(Walker *pWalker, Expr *pExpr){
 ** Preevaluate constant subexpressions within pExpr and store the
 ** results in registers.  Modify pExpr so that the constant subexpresions
 ** are TK_REGISTER opcodes that refer to the precomputed values.
+**
+** This routine is a no-op if the jump to the cookie-check code has
+** already occur.  Since the cookie-check jump is generated prior to
+** any other serious processing, this check ensures that there is no
+** way to accidently bypass the constant initializations.
+**
+** This routine is also a no-op if the SQLITE_FactorOutConst optimization
+** is disabled via the sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS)
+** interface.  This allows test logic to verify that the same answer is
+** obtained for queries regardless of whether or not constants are
+** precomputed into registers or if they are inserted in-line.
 */
 SQLITE_PRIVATE void sqlite3ExprCodeConstants(Parse *pParse, Expr *pExpr){
   Walker w;
+  if( pParse->cookieGoto ) return;
+  if( (pParse->db->flags & SQLITE_FactorOutConst)!=0 ) return;
   w.xExprCallback = evalConstExpr;
   w.xSelectCallback = 0;
   w.pParse = pParse;
@@ -58742,24 +76638,75 @@ SQLITE_PRIVATE int sqlite3ExprCodeExprList(
   int i, n;
   assert( pList!=0 );
   assert( target>0 );
+  assert( pParse->pVdbe!=0 );  /* Never gets this far otherwise */
   n = pList->nExpr;
   for(pItem=pList->a, i=0; i<n; i++, pItem++){
-    if( pItem->iAlias ){
-      int iReg = codeAlias(pParse, pItem->iAlias, pItem->pExpr, target+i);
-      Vdbe *v = sqlite3GetVdbe(pParse);
-      if( iReg!=target+i ){
-        sqlite3VdbeAddOp2(v, OP_SCopy, iReg, target+i);
-      }
-    }else{
-      sqlite3ExprCode(pParse, pItem->pExpr, target+i);
-    }
-    if( doHardCopy ){
-      sqlite3ExprHardCopy(pParse, target, n);
+    Expr *pExpr = pItem->pExpr;
+    int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
+    if( inReg!=target+i ){
+      sqlite3VdbeAddOp2(pParse->pVdbe, doHardCopy ? OP_Copy : OP_SCopy,
+                        inReg, target+i);
     }
   }
   return n;
 }
 
+/*
+** Generate code for a BETWEEN operator.
+**
+**    x BETWEEN y AND z
+**
+** The above is equivalent to 
+**
+**    x>=y AND x<=z
+**
+** Code it as such, taking care to do the common subexpression
+** elementation of x.
+*/
+static void exprCodeBetween(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* The BETWEEN expression */
+  int dest,         /* Jump here if the jump is taken */
+  int jumpIfTrue,   /* Take the jump if the BETWEEN is true */
+  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
+){
+  Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
+  Expr compLeft;    /* The  x>=y  term */
+  Expr compRight;   /* The  x<=z  term */
+  Expr exprX;       /* The  x  subexpression */
+  int regFree1 = 0; /* Temporary use register */
+
+  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+  exprX = *pExpr->pLeft;
+  exprAnd.op = TK_AND;
+  exprAnd.pLeft = &compLeft;
+  exprAnd.pRight = &compRight;
+  compLeft.op = TK_GE;
+  compLeft.pLeft = &exprX;
+  compLeft.pRight = pExpr->x.pList->a[0].pExpr;
+  compRight.op = TK_LE;
+  compRight.pLeft = &exprX;
+  compRight.pRight = pExpr->x.pList->a[1].pExpr;
+  exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
+  exprX.op = TK_REGISTER;
+  if( jumpIfTrue ){
+    sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
+  }else{
+    sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+
+  /* Ensure adequate test coverage */
+  testcase( jumpIfTrue==0 && jumpIfNull==0 && regFree1==0 );
+  testcase( jumpIfTrue==0 && jumpIfNull==0 && regFree1!=0 );
+  testcase( jumpIfTrue==0 && jumpIfNull!=0 && regFree1==0 );
+  testcase( jumpIfTrue==0 && jumpIfNull!=0 && regFree1!=0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull==0 && regFree1==0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull==0 && regFree1!=0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull!=0 && regFree1==0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull!=0 && regFree1!=0 );
+}
+
 /*
 ** Generate code for a boolean expression such that a jump is made
 ** to the label "dest" if the expression is true but execution
@@ -58782,29 +76729,24 @@ SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int
   int r1, r2;
 
   assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
-  if( v==0 || pExpr==0 ) return;
+  if( NEVER(v==0) )     return;  /* Existance of VDBE checked by caller */
+  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
   op = pExpr->op;
   switch( op ){
     case TK_AND: {
       int d2 = sqlite3VdbeMakeLabel(v);
       testcase( jumpIfNull==0 );
-      testcase( pParse->disableColCache==0 );
+      sqlite3ExprCachePush(pParse);
       sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
-      pParse->disableColCache++;
       sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
-      assert( pParse->disableColCache>0 );
-      pParse->disableColCache--;
       sqlite3VdbeResolveLabel(v, d2);
+      sqlite3ExprCachePop(pParse, 1);
       break;
     }
     case TK_OR: {
       testcase( jumpIfNull==0 );
-      testcase( pParse->disableColCache==0 );
       sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
-      pParse->disableColCache++;
       sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
-      assert( pParse->disableColCache>0 );
-      pParse->disableColCache--;
       break;
     }
     case TK_NOT: {
@@ -58831,14 +76773,27 @@ SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int
       testcase( op==TK_EQ );
       testcase( op==TK_NE );
       testcase( jumpIfNull==0 );
-      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
-                                  pExpr->pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                   r1, r2, dest, jumpIfNull);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       break;
     }
+    case TK_IS:
+    case TK_ISNOT: {
+      testcase( op==TK_IS );
+      testcase( op==TK_ISNOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
     case TK_ISNULL:
     case TK_NOTNULL: {
       assert( TK_ISNULL==OP_IsNull );
@@ -58851,37 +76806,20 @@ SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int
       break;
     }
     case TK_BETWEEN: {
-      /*    x BETWEEN y AND z
-      **
-      ** Is equivalent to 
-      **
-      **    x>=y AND x<=z
-      **
-      ** Code it as such, taking care to do the common subexpression
-      ** elementation of x.
-      */
-      Expr exprAnd;
-      Expr compLeft;
-      Expr compRight;
-      Expr exprX;
-
-      exprX = *pExpr->pLeft;
-      exprAnd.op = TK_AND;
-      exprAnd.pLeft = &compLeft;
-      exprAnd.pRight = &compRight;
-      compLeft.op = TK_GE;
-      compLeft.pLeft = &exprX;
-      compLeft.pRight = pExpr->pList->a[0].pExpr;
-      compRight.op = TK_LE;
-      compRight.pLeft = &exprX;
-      compRight.pRight = pExpr->pList->a[1].pExpr;
-      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
-      testcase( regFree1==0 );
-      exprX.op = TK_REGISTER;
       testcase( jumpIfNull==0 );
-      sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
+      exprCodeBetween(pParse, pExpr, dest, 1, jumpIfNull);
       break;
     }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = jumpIfNull ? dest : destIfFalse;
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, dest);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      break;
+    }
+#endif
     default: {
       r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
       sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);
@@ -58911,7 +76849,8 @@ SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int
   int r1, r2;
 
   assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
-  if( v==0 || pExpr==0 ) return;
+  if( NEVER(v==0) ) return; /* Existance of VDBE checked by caller */
+  if( pExpr==0 )    return;
 
   /* The value of pExpr->op and op are related as follows:
   **
@@ -58947,27 +76886,22 @@ SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int
   switch( pExpr->op ){
     case TK_AND: {
       testcase( jumpIfNull==0 );
-      testcase( pParse->disableColCache==0 );
       sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
-      pParse->disableColCache++;
       sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
-      assert( pParse->disableColCache>0 );
-      pParse->disableColCache--;
       break;
     }
     case TK_OR: {
       int d2 = sqlite3VdbeMakeLabel(v);
       testcase( jumpIfNull==0 );
-      testcase( pParse->disableColCache==0 );
+      sqlite3ExprCachePush(pParse);
       sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, jumpIfNull^SQLITE_JUMPIFNULL);
-      pParse->disableColCache++;
       sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
-      assert( pParse->disableColCache>0 );
-      pParse->disableColCache--;
       sqlite3VdbeResolveLabel(v, d2);
+      sqlite3ExprCachePop(pParse, 1);
       break;
     }
     case TK_NOT: {
+      testcase( jumpIfNull==0 );
       sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
       break;
     }
@@ -58984,14 +76918,27 @@ SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int
       testcase( op==TK_EQ );
       testcase( op==TK_NE );
       testcase( jumpIfNull==0 );
-      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
-                                  pExpr->pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                   r1, r2, dest, jumpIfNull);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       break;
     }
+    case TK_IS:
+    case TK_ISNOT: {
+      testcase( pExpr->op==TK_IS );
+      testcase( pExpr->op==TK_ISNOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      op = (pExpr->op==TK_IS) ? TK_NE : TK_EQ;
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
     case TK_ISNULL:
     case TK_NOTNULL: {
       testcase( op==TK_ISNULL );
@@ -59002,37 +76949,22 @@ SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int
       break;
     }
     case TK_BETWEEN: {
-      /*    x BETWEEN y AND z
-      **
-      ** Is equivalent to 
-      **
-      **    x>=y AND x<=z
-      **
-      ** Code it as such, taking care to do the common subexpression
-      ** elementation of x.
-      */
-      Expr exprAnd;
-      Expr compLeft;
-      Expr compRight;
-      Expr exprX;
-
-      exprX = *pExpr->pLeft;
-      exprAnd.op = TK_AND;
-      exprAnd.pLeft = &compLeft;
-      exprAnd.pRight = &compRight;
-      compLeft.op = TK_GE;
-      compLeft.pLeft = &exprX;
-      compLeft.pRight = pExpr->pList->a[0].pExpr;
-      compRight.op = TK_LE;
-      compRight.pLeft = &exprX;
-      compRight.pRight = pExpr->pList->a[1].pExpr;
-      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
-      testcase( regFree1==0 );
-      exprX.op = TK_REGISTER;
       testcase( jumpIfNull==0 );
-      sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
+      exprCodeBetween(pParse, pExpr, dest, 0, jumpIfNull);
       break;
     }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      if( jumpIfNull ){
+        sqlite3ExprCodeIN(pParse, pExpr, dest, dest);
+      }else{
+        int destIfNull = sqlite3VdbeMakeLabel(v);
+        sqlite3ExprCodeIN(pParse, pExpr, dest, destIfNull);
+        sqlite3VdbeResolveLabel(v, destIfNull);
+      }
+      break;
+    }
+#endif
     default: {
       r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
       sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);
@@ -59046,51 +76978,133 @@ SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int
 }
 
 /*
-** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
-** if they are identical and return FALSE if they differ in any way.
+** Do a deep comparison of two expression trees.  Return 0 if the two
+** expressions are completely identical.  Return 1 if they differ only
+** by a COLLATE operator at the top level.  Return 2 if there are differences
+** other than the top-level COLLATE operator.
 **
-** Sometimes this routine will return FALSE even if the two expressions
+** Sometimes this routine will return 2 even if the two expressions
 ** really are equivalent.  If we cannot prove that the expressions are
-** identical, we return FALSE just to be safe.  So if this routine
-** returns false, then you do not really know for certain if the two
-** expressions are the same.  But if you get a TRUE return, then you
+** identical, we return 2 just to be safe.  So if this routine
+** returns 2, then you do not really know for certain if the two
+** expressions are the same.  But if you get a 0 or 1 return, then you
 ** can be sure the expressions are the same.  In the places where
-** this routine is used, it does not hurt to get an extra FALSE - that
+** this routine is used, it does not hurt to get an extra 2 - that
 ** just might result in some slightly slower code.  But returning
-** an incorrect TRUE could lead to a malfunction.
+** an incorrect 0 or 1 could lead to a malfunction.
 */
 SQLITE_PRIVATE int sqlite3ExprCompare(Expr *pA, Expr *pB){
-  int i;
   if( pA==0||pB==0 ){
-    return pB==pA;
+    return pB==pA ? 0 : 2;
   }
-  if( pA->op!=pB->op ) return 0;
-  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 0;
-  if( !sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 0;
-  if( !sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 0;
-  if( pA->pList ){
-    if( pB->pList==0 ) return 0;
-    if( pA->pList->nExpr!=pB->pList->nExpr ) return 0;
-    for(i=0; i<pA->pList->nExpr; i++){
-      if( !sqlite3ExprCompare(pA->pList->a[i].pExpr, pB->pList->a[i].pExpr) ){
-        return 0;
-      }
+  assert( !ExprHasAnyProperty(pA, EP_TokenOnly|EP_Reduced) );
+  assert( !ExprHasAnyProperty(pB, EP_TokenOnly|EP_Reduced) );
+  if( ExprHasProperty(pA, EP_xIsSelect) || ExprHasProperty(pB, EP_xIsSelect) ){
+    return 2;
+  }
+  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
+  if( pA->op!=pB->op ) return 2;
+  if( sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 2;
+  if( sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 2;
+  if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList) ) return 2;
+  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 2;
+  if( ExprHasProperty(pA, EP_IntValue) ){
+    if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){
+      return 2;
     }
-  }else if( pB->pList ){
-    return 0;
-  }
-  if( pA->pSelect || pB->pSelect ) return 0;
-  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 0;
-  if( pA->op!=TK_COLUMN && pA->token.z ){
-    if( pB->token.z==0 ) return 0;
-    if( pB->token.n!=pA->token.n ) return 0;
-    if( sqlite3StrNICmp((char*)pA->token.z,(char*)pB->token.z,pB->token.n)!=0 ){
-      return 0;
+  }else if( pA->op!=TK_COLUMN && ALWAYS(pA->op!=TK_AGG_COLUMN) && pA->u.zToken){
+    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 2;
+    if( strcmp(pA->u.zToken,pB->u.zToken)!=0 ){
+      return 2;
     }
   }
-  return 1;
+  if( (pA->flags & EP_ExpCollate)!=(pB->flags & EP_ExpCollate) ) return 1;
+  if( (pA->flags & EP_ExpCollate)!=0 && pA->pColl!=pB->pColl ) return 2;
+  return 0;
 }
 
+/*
+** Compare two ExprList objects.  Return 0 if they are identical and 
+** non-zero if they differ in any way.
+**
+** This routine might return non-zero for equivalent ExprLists.  The
+** only consequence will be disabled optimizations.  But this routine
+** must never return 0 if the two ExprList objects are different, or
+** a malfunction will result.
+**
+** Two NULL pointers are considered to be the same.  But a NULL pointer
+** always differs from a non-NULL pointer.
+*/
+SQLITE_PRIVATE int sqlite3ExprListCompare(ExprList *pA, ExprList *pB){
+  int i;
+  if( pA==0 && pB==0 ) return 0;
+  if( pA==0 || pB==0 ) return 1;
+  if( pA->nExpr!=pB->nExpr ) return 1;
+  for(i=0; i<pA->nExpr; i++){
+    Expr *pExprA = pA->a[i].pExpr;
+    Expr *pExprB = pB->a[i].pExpr;
+    if( pA->a[i].sortOrder!=pB->a[i].sortOrder ) return 1;
+    if( sqlite3ExprCompare(pExprA, pExprB) ) return 1;
+  }
+  return 0;
+}
+
+/*
+** An instance of the following structure is used by the tree walker
+** to count references to table columns in the arguments of an 
+** aggregate function, in order to implement the
+** sqlite3FunctionThisSrc() routine.
+*/
+struct SrcCount {
+  SrcList *pSrc;   /* One particular FROM clause in a nested query */
+  int nThis;       /* Number of references to columns in pSrcList */
+  int nOther;      /* Number of references to columns in other FROM clauses */
+};
+
+/*
+** Count the number of references to columns.
+*/
+static int exprSrcCount(Walker *pWalker, Expr *pExpr){
+  /* The NEVER() on the second term is because sqlite3FunctionUsesThisSrc()
+  ** is always called before sqlite3ExprAnalyzeAggregates() and so the
+  ** TK_COLUMNs have not yet been converted into TK_AGG_COLUMN.  If
+  ** sqlite3FunctionUsesThisSrc() is used differently in the future, the
+  ** NEVER() will need to be removed. */
+  if( pExpr->op==TK_COLUMN || NEVER(pExpr->op==TK_AGG_COLUMN) ){
+    int i;
+    struct SrcCount *p = pWalker->u.pSrcCount;
+    SrcList *pSrc = p->pSrc;
+    for(i=0; i<pSrc->nSrc; i++){
+      if( pExpr->iTable==pSrc->a[i].iCursor ) break;
+    }
+    if( i<pSrc->nSrc ){
+      p->nThis++;
+    }else{
+      p->nOther++;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Determine if any of the arguments to the pExpr Function reference
+** pSrcList.  Return true if they do.  Also return true if the function
+** has no arguments or has only constant arguments.  Return false if pExpr
+** references columns but not columns of tables found in pSrcList.
+*/
+SQLITE_PRIVATE int sqlite3FunctionUsesThisSrc(Expr *pExpr, SrcList *pSrcList){
+  Walker w;
+  struct SrcCount cnt;
+  assert( pExpr->op==TK_AGG_FUNCTION );
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = exprSrcCount;
+  w.u.pSrcCount = &cnt;
+  cnt.pSrc = pSrcList;
+  cnt.nThis = 0;
+  cnt.nOther = 0;
+  sqlite3WalkExprList(&w, pExpr->x.pList);
+  return cnt.nThis>0 || cnt.nOther==0;
+}
 
 /*
 ** Add a new element to the pAggInfo->aCol[] array.  Return the index of
@@ -59102,9 +77116,7 @@ static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){
        db,
        pInfo->aCol,
        sizeof(pInfo->aCol[0]),
-       3,
        &pInfo->nColumn,
-       &pInfo->nColumnAlloc,
        &i
   );
   return i;
@@ -59120,9 +77132,7 @@ static int addAggInfoFunc(sqlite3 *db, AggInfo *pInfo){
        db, 
        pInfo->aFunc,
        sizeof(pInfo->aFunc[0]),
-       3,
        &pInfo->nFunc,
-       &pInfo->nFuncAlloc,
        &i
   );
   return i;
@@ -59147,10 +77157,11 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
       testcase( pExpr->op==TK_COLUMN );
       /* Check to see if the column is in one of the tables in the FROM
       ** clause of the aggregate query */
-      if( pSrcList ){
+      if( ALWAYS(pSrcList!=0) ){
         struct SrcList_item *pItem = pSrcList->a;
         for(i=0; i<pSrcList->nSrc; i++, pItem++){
           struct AggInfo_col *pCol;
+          assert( !ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_Reduced) );
           if( pExpr->iTable==pItem->iCursor ){
             /* If we reach this point, it means that pExpr refers to a table
             ** that is in the FROM clause of the aggregate query.  
@@ -59199,9 +77210,10 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
             ** Convert the pExpr to be a TK_AGG_COLUMN referring to that
             ** pAggInfo->aCol[] entry.
             */
+            ExprSetIrreducible(pExpr);
             pExpr->pAggInfo = pAggInfo;
             pExpr->op = TK_AGG_COLUMN;
-            pExpr->iAgg = k;
+            pExpr->iAgg = (i16)k;
             break;
           } /* endif pExpr->iTable==pItem->iCursor */
         } /* end loop over pSrcList */
@@ -59209,15 +77221,15 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
       return WRC_Prune;
     }
     case TK_AGG_FUNCTION: {
-      /* The pNC->nDepth==0 test causes aggregate functions in subqueries
-      ** to be ignored */
-      if( pNC->nDepth==0 ){
+      if( (pNC->ncFlags & NC_InAggFunc)==0
+       && pWalker->walkerDepth==pExpr->op2
+      ){
         /* Check to see if pExpr is a duplicate of another aggregate 
         ** function that is already in the pAggInfo structure
         */
         struct AggInfo_func *pItem = pAggInfo->aFunc;
         for(i=0; i<pAggInfo->nFunc; i++, pItem++){
-          if( sqlite3ExprCompare(pItem->pExpr, pExpr) ){
+          if( sqlite3ExprCompare(pItem->pExpr, pExpr)==0 ){
             break;
           }
         }
@@ -59227,12 +77239,14 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
           u8 enc = ENC(pParse->db);
           i = addAggInfoFunc(pParse->db, pAggInfo);
           if( i>=0 ){
+            assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
             pItem = &pAggInfo->aFunc[i];
             pItem->pExpr = pExpr;
             pItem->iMem = ++pParse->nMem;
+            assert( !ExprHasProperty(pExpr, EP_IntValue) );
             pItem->pFunc = sqlite3FindFunction(pParse->db,
-                   (char*)pExpr->token.z, pExpr->token.n,
-                   pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
+                   pExpr->u.zToken, sqlite3Strlen30(pExpr->u.zToken),
+                   pExpr->x.pList ? pExpr->x.pList->nExpr : 0, enc, 0);
             if( pExpr->flags & EP_Distinct ){
               pItem->iDistinct = pParse->nTab++;
             }else{
@@ -59242,24 +77256,20 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
         }
         /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
         */
-        pExpr->iAgg = i;
+        assert( !ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+        ExprSetIrreducible(pExpr);
+        pExpr->iAgg = (i16)i;
         pExpr->pAggInfo = pAggInfo;
-        return WRC_Prune;
       }
+      return WRC_Prune;
     }
   }
   return WRC_Continue;
 }
 static int analyzeAggregatesInSelect(Walker *pWalker, Select *pSelect){
-  NameContext *pNC = pWalker->u.pNC;
-  if( pNC->nDepth==0 ){
-    pNC->nDepth++;
-    sqlite3WalkSelect(pWalker, pSelect);
-    pNC->nDepth--;
-    return WRC_Prune;
-  }else{
-    return WRC_Continue;
-  }
+  UNUSED_PARAMETER(pWalker);
+  UNUSED_PARAMETER(pSelect);
+  return WRC_Continue;
 }
 
 /*
@@ -59272,9 +77282,11 @@ static int analyzeAggregatesInSelect(Walker *pWalker, Select *pSelect){
 */
 SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
   Walker w;
+  memset(&w, 0, sizeof(w));
   w.xExprCallback = analyzeAggregate;
   w.xSelectCallback = analyzeAggregatesInSelect;
   w.u.pNC = pNC;
+  assert( pNC->pSrcList!=0 );
   sqlite3WalkExpr(&w, pExpr);
 }
 
@@ -59295,7 +77307,7 @@ SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext *pNC, ExprList *pList)
 }
 
 /*
-** Allocate or deallocate temporary use registers during code generation.
+** Allocate a single new register for use to hold some intermediate result.
 */
 SQLITE_PRIVATE int sqlite3GetTempReg(Parse *pParse){
   if( pParse->nTempReg==0 ){
@@ -59303,9 +77315,25 @@ SQLITE_PRIVATE int sqlite3GetTempReg(Parse *pParse){
   }
   return pParse->aTempReg[--pParse->nTempReg];
 }
+
+/*
+** Deallocate a register, making available for reuse for some other
+** purpose.
+**
+** If a register is currently being used by the column cache, then
+** the dallocation is deferred until the column cache line that uses
+** the register becomes stale.
+*/
 SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
   if( iReg && pParse->nTempReg<ArraySize(pParse->aTempReg) ){
-    sqlite3ExprWritableRegister(pParse, iReg);
+    int i;
+    struct yColCache *p;
+    for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+      if( p->iReg==iReg ){
+        p->tempReg = 1;
+        return;
+      }
+    }
     pParse->aTempReg[pParse->nTempReg++] = iReg;
   }
 }
@@ -59317,7 +77345,8 @@ SQLITE_PRIVATE int sqlite3GetTempRange(Parse *pParse, int nReg){
   int i, n;
   i = pParse->iRangeReg;
   n = pParse->nRangeReg;
-  if( nReg<=n && !usedAsColumnCache(pParse, i, i+n-1) ){
+  if( nReg<=n ){
+    assert( !usedAsColumnCache(pParse, i, i+n-1) );
     pParse->iRangeReg += nReg;
     pParse->nRangeReg -= nReg;
   }else{
@@ -59327,12 +77356,21 @@ SQLITE_PRIVATE int sqlite3GetTempRange(Parse *pParse, int nReg){
   return i;
 }
 SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
+  sqlite3ExprCacheRemove(pParse, iReg, nReg);
   if( nReg>pParse->nRangeReg ){
     pParse->nRangeReg = nReg;
     pParse->iRangeReg = iReg;
   }
 }
 
+/*
+** Mark all temporary registers as being unavailable for reuse.
+*/
+SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse *pParse){
+  pParse->nTempReg = 0;
+  pParse->nRangeReg = 0;
+}
+
 /************** End of expr.c ************************************************/
 /************** Begin file alter.c *******************************************/
 /*
@@ -59348,8 +77386,6 @@ SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
 *************************************************************************
 ** This file contains C code routines that used to generate VDBE code
 ** that implements the ALTER TABLE command.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -59402,7 +77438,7 @@ static void renameTableFunc(
       }
 
       /* Store the token that zCsr points to in tname. */
-      tname.z = zCsr;
+      tname.z = (char*)zCsr;
       tname.n = len;
 
       /* Advance zCsr to the next token. Store that token type in 'token',
@@ -59415,12 +77451,75 @@ static void renameTableFunc(
       assert( len>0 );
     } while( token!=TK_LP && token!=TK_USING );
 
-    zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", tname.z - zSql, zSql, 
+    zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", ((u8*)tname.z) - zSql, zSql, 
        zTableName, tname.z+tname.n);
     sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
   }
 }
 
+/*
+** This C function implements an SQL user function that is used by SQL code
+** generated by the ALTER TABLE ... RENAME command to modify the definition
+** of any foreign key constraints that use the table being renamed as the 
+** parent table. It is passed three arguments:
+**
+**   1) The complete text of the CREATE TABLE statement being modified,
+**   2) The old name of the table being renamed, and
+**   3) The new name of the table being renamed.
+**
+** It returns the new CREATE TABLE statement. For example:
+**
+**   sqlite_rename_parent('CREATE TABLE t1(a REFERENCES t2)', 't2', 't3')
+**       -> 'CREATE TABLE t1(a REFERENCES t3)'
+*/
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+static void renameParentFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char *zOutput = 0;
+  char *zResult;
+  unsigned char const *zInput = sqlite3_value_text(argv[0]);
+  unsigned char const *zOld = sqlite3_value_text(argv[1]);
+  unsigned char const *zNew = sqlite3_value_text(argv[2]);
+
+  unsigned const char *z;         /* Pointer to token */
+  int n;                          /* Length of token z */
+  int token;                      /* Type of token */
+
+  UNUSED_PARAMETER(NotUsed);
+  for(z=zInput; *z; z=z+n){
+    n = sqlite3GetToken(z, &token);
+    if( token==TK_REFERENCES ){
+      char *zParent;
+      do {
+        z += n;
+        n = sqlite3GetToken(z, &token);
+      }while( token==TK_SPACE );
+
+      zParent = sqlite3DbStrNDup(db, (const char *)z, n);
+      if( zParent==0 ) break;
+      sqlite3Dequote(zParent);
+      if( 0==sqlite3StrICmp((const char *)zOld, zParent) ){
+        char *zOut = sqlite3MPrintf(db, "%s%.*s\"%w\"", 
+            (zOutput?zOutput:""), z-zInput, zInput, (const char *)zNew
+        );
+        sqlite3DbFree(db, zOutput);
+        zOutput = zOut;
+        zInput = &z[n];
+      }
+      sqlite3DbFree(db, zParent);
+    }
+  }
+
+  zResult = sqlite3MPrintf(db, "%s%s", (zOutput?zOutput:""), zInput), 
+  sqlite3_result_text(context, zResult, -1, SQLITE_DYNAMIC);
+  sqlite3DbFree(db, zOutput);
+}
+#endif
+
 #ifndef SQLITE_OMIT_TRIGGER
 /* This function is used by SQL generated to implement the
 ** ALTER TABLE command. The first argument is the text of a CREATE TRIGGER 
@@ -59461,7 +77560,7 @@ static void renameTriggerFunc(
       }
 
       /* Store the token that zCsr points to in tname. */
-      tname.z = zCsr;
+      tname.z = (char*)zCsr;
       tname.n = len;
 
       /* Advance zCsr to the next token. Store that token type in 'token',
@@ -59491,7 +77590,7 @@ static void renameTriggerFunc(
     /* Variable tname now contains the token that is the old table-name
     ** in the CREATE TRIGGER statement.
     */
-    zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", tname.z - zSql, zSql, 
+    zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", ((u8*)tname.z) - zSql, zSql, 
        zTableName, tname.z+tname.n);
     sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
   }
@@ -59501,15 +77600,69 @@ static void renameTriggerFunc(
 /*
 ** Register built-in functions used to help implement ALTER TABLE
 */
-SQLITE_PRIVATE void sqlite3AlterFunctions(sqlite3 *db){
-  sqlite3CreateFunc(db, "sqlite_rename_table", 2, SQLITE_UTF8, 0,
-                         renameTableFunc, 0, 0);
+SQLITE_PRIVATE void sqlite3AlterFunctions(void){
+  static SQLITE_WSD FuncDef aAlterTableFuncs[] = {
+    FUNCTION(sqlite_rename_table,   2, 0, 0, renameTableFunc),
 #ifndef SQLITE_OMIT_TRIGGER
-  sqlite3CreateFunc(db, "sqlite_rename_trigger", 2, SQLITE_UTF8, 0,
-                         renameTriggerFunc, 0, 0);
+    FUNCTION(sqlite_rename_trigger, 2, 0, 0, renameTriggerFunc),
 #endif
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+    FUNCTION(sqlite_rename_parent,  3, 0, 0, renameParentFunc),
+#endif
+  };
+  int i;
+  FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
+  FuncDef *aFunc = (FuncDef*)&GLOBAL(FuncDef, aAlterTableFuncs);
+
+  for(i=0; i<ArraySize(aAlterTableFuncs); i++){
+    sqlite3FuncDefInsert(pHash, &aFunc[i]);
+  }
 }
 
+/*
+** This function is used to create the text of expressions of the form:
+**
+**   name=<constant1> OR name=<constant2> OR ...
+**
+** If argument zWhere is NULL, then a pointer string containing the text 
+** "name=<constant>" is returned, where <constant> is the quoted version
+** of the string passed as argument zConstant. The returned buffer is
+** allocated using sqlite3DbMalloc(). It is the responsibility of the
+** caller to ensure that it is eventually freed.
+**
+** If argument zWhere is not NULL, then the string returned is 
+** "<where> OR name=<constant>", where <where> is the contents of zWhere.
+** In this case zWhere is passed to sqlite3DbFree() before returning.
+** 
+*/
+static char *whereOrName(sqlite3 *db, char *zWhere, char *zConstant){
+  char *zNew;
+  if( !zWhere ){
+    zNew = sqlite3MPrintf(db, "name=%Q", zConstant);
+  }else{
+    zNew = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, zConstant);
+    sqlite3DbFree(db, zWhere);
+  }
+  return zNew;
+}
+
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+/*
+** Generate the text of a WHERE expression which can be used to select all
+** tables that have foreign key constraints that refer to table pTab (i.e.
+** constraints for which pTab is the parent table) from the sqlite_master
+** table.
+*/
+static char *whereForeignKeys(Parse *pParse, Table *pTab){
+  FKey *p;
+  char *zWhere = 0;
+  for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+    zWhere = whereOrName(pParse->db, zWhere, p->pFrom->zName);
+  }
+  return zWhere;
+}
+#endif
+
 /*
 ** Generate the text of a WHERE expression which can be used to select all
 ** temporary triggers on table pTab from the sqlite_temp_master table. If
@@ -59519,7 +77672,6 @@ SQLITE_PRIVATE void sqlite3AlterFunctions(sqlite3 *db){
 static char *whereTempTriggers(Parse *pParse, Table *pTab){
   Trigger *pTrig;
   char *zWhere = 0;
-  char *tmp = 0;
   const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */
 
   /* If the table is not located in the temp-db (in which case NULL is 
@@ -59529,18 +77681,17 @@ static char *whereTempTriggers(Parse *pParse, Table *pTab){
   */
   if( pTab->pSchema!=pTempSchema ){
     sqlite3 *db = pParse->db;
-    for( pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext ){
+    for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
       if( pTrig->pSchema==pTempSchema ){
-        if( !zWhere ){
-          zWhere = sqlite3MPrintf(db, "name=%Q", pTrig->name);
-        }else{
-          tmp = zWhere;
-          zWhere = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, pTrig->name);
-          sqlite3DbFree(db, tmp);
-        }
+        zWhere = whereOrName(db, zWhere, pTrig->zName);
       }
     }
   }
+  if( zWhere ){
+    char *zNew = sqlite3MPrintf(pParse->db, "type='trigger' AND (%s)", zWhere);
+    sqlite3DbFree(pParse->db, zWhere);
+    zWhere = zNew;
+  }
   return zWhere;
 }
 
@@ -59561,38 +77712,54 @@ static void reloadTableSchema(Parse *pParse, Table *pTab, const char *zName){
 #endif
 
   v = sqlite3GetVdbe(pParse);
-  if( !v ) return;
+  if( NEVER(v==0) ) return;
   assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
   assert( iDb>=0 );
 
 #ifndef SQLITE_OMIT_TRIGGER
   /* Drop any table triggers from the internal schema. */
-  for(pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext){
+  for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
     int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
     assert( iTrigDb==iDb || iTrigDb==1 );
-    sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->name, 0);
+    sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->zName, 0);
   }
 #endif
 
-  /* Drop the table and index from the internal schema */
+  /* Drop the table and index from the internal schema.  */
   sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
 
   /* Reload the table, index and permanent trigger schemas. */
   zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
   if( !zWhere ) return;
-  sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
+  sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);
 
 #ifndef SQLITE_OMIT_TRIGGER
   /* Now, if the table is not stored in the temp database, reload any temp 
   ** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined. 
   */
   if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
-    sqlite3VdbeAddOp4(v, OP_ParseSchema, 1, 0, 0, zWhere, P4_DYNAMIC);
+    sqlite3VdbeAddParseSchemaOp(v, 1, zWhere);
   }
 #endif
 }
 
+/*
+** Parameter zName is the name of a table that is about to be altered
+** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).
+** If the table is a system table, this function leaves an error message
+** in pParse->zErr (system tables may not be altered) and returns non-zero.
+**
+** Or, if zName is not a system table, zero is returned.
+*/
+static int isSystemTable(Parse *pParse, const char *zName){
+  if( sqlite3Strlen30(zName)>6 && 0==sqlite3StrNICmp(zName, "sqlite_", 7) ){
+    sqlite3ErrorMsg(pParse, "table %s may not be altered", zName);
+    return 1;
+  }
+  return 0;
+}
+
 /*
 ** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy" 
 ** command. 
@@ -59613,9 +77780,11 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
 #ifndef SQLITE_OMIT_TRIGGER
   char *zWhere = 0;         /* Where clause to locate temp triggers */
 #endif
-  int isVirtualRename = 0;  /* True if this is a v-table with an xRename() */
-  
-  if( db->mallocFailed ) goto exit_rename_table;
+  VTable *pVTab = 0;        /* Non-zero if this is a v-tab with an xRename() */
+  int savedDbFlags;         /* Saved value of db->flags */
+
+  savedDbFlags = db->flags;  
+  if( NEVER(db->mallocFailed) ) goto exit_rename_table;
   assert( pSrc->nSrc==1 );
   assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
 
@@ -59623,6 +77792,7 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
   if( !pTab ) goto exit_rename_table;
   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
   zDb = db->aDb[iDb].zName;
+  db->flags |= SQLITE_PreferBuiltin;
 
   /* Get a NULL terminated version of the new table name. */
   zName = sqlite3NameFromToken(db, pName);
@@ -59640,14 +77810,11 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
   /* Make sure it is not a system table being altered, or a reserved name
   ** that the table is being renamed to.
   */
-  if( sqlite3Strlen30(pTab->zName)>6 
-   && 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7)
-  ){
-    sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
+  if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
     goto exit_rename_table;
   }
-  if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
-    goto exit_rename_table;
+  if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){ goto
+    exit_rename_table;
   }
 
 #ifndef SQLITE_OMIT_VIEW
@@ -59668,8 +77835,11 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
     goto exit_rename_table;
   }
-  if( IsVirtual(pTab) && pTab->pMod->pModule->xRename ){
-    isVirtualRename = 1;
+  if( IsVirtual(pTab) ){
+    pVTab = sqlite3GetVTable(db, pTab);
+    if( pVTab->pVtab->pModule->xRename==0 ){
+      pVTab = 0;
+    }
   }
 #endif
 
@@ -59682,7 +77852,7 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
   if( v==0 ){
     goto exit_rename_table;
   }
-  sqlite3BeginWriteOperation(pParse, isVirtualRename, iDb);
+  sqlite3BeginWriteOperation(pParse, pVTab!=0, iDb);
   sqlite3ChangeCookie(pParse, iDb);
 
   /* If this is a virtual table, invoke the xRename() function if
@@ -59691,10 +77861,11 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
   ** SQLite tables) that are identified by the name of the virtual table.
   */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-  if( isVirtualRename ){
+  if( pVTab ){
     int i = ++pParse->nMem;
     sqlite3VdbeAddOp4(v, OP_String8, 0, i, 0, zName, 0);
-    sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pTab->pVtab, P4_VTAB);
+    sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pVTab, P4_VTAB);
+    sqlite3MayAbort(pParse);
   }
 #endif
 
@@ -59702,6 +77873,21 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
   zTabName = pTab->zName;
   nTabName = sqlite3Utf8CharLen(zTabName, -1);
 
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+  if( db->flags&SQLITE_ForeignKeys ){
+    /* If foreign-key support is enabled, rewrite the CREATE TABLE 
+    ** statements corresponding to all child tables of foreign key constraints
+    ** for which the renamed table is the parent table.  */
+    if( (zWhere=whereForeignKeys(pParse, pTab))!=0 ){
+      sqlite3NestedParse(pParse, 
+          "UPDATE \"%w\".%s SET "
+              "sql = sqlite_rename_parent(sql, %Q, %Q) "
+              "WHERE %s;", zDb, SCHEMA_TABLE(iDb), zTabName, zName, zWhere);
+      sqlite3DbFree(db, zWhere);
+    }
+  }
+#endif
+
   /* Modify the sqlite_master table to use the new table name. */
   sqlite3NestedParse(pParse,
       "UPDATE %Q.%s SET "
@@ -59718,7 +77904,7 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
             "WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
              "'sqlite_autoindex_' || %Q || substr(name,%d+18) "
             "ELSE name END "
-      "WHERE tbl_name=%Q AND "
+      "WHERE tbl_name=%Q COLLATE nocase AND "
           "(type='table' OR type='index' OR type='trigger');", 
       zDb, SCHEMA_TABLE(iDb), zName, zName, zName, 
 #ifndef SQLITE_OMIT_TRIGGER
@@ -59753,15 +77939,53 @@ SQLITE_PRIVATE void sqlite3AlterRenameTable(
   }
 #endif
 
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+  if( db->flags&SQLITE_ForeignKeys ){
+    FKey *p;
+    for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+      Table *pFrom = p->pFrom;
+      if( pFrom!=pTab ){
+        reloadTableSchema(pParse, p->pFrom, pFrom->zName);
+      }
+    }
+  }
+#endif
+
   /* Drop and reload the internal table schema. */
   reloadTableSchema(pParse, pTab, zName);
 
 exit_rename_table:
   sqlite3SrcListDelete(db, pSrc);
   sqlite3DbFree(db, zName);
+  db->flags = savedDbFlags;
 }
 
 
+/*
+** Generate code to make sure the file format number is at least minFormat.
+** The generated code will increase the file format number if necessary.
+*/
+SQLITE_PRIVATE void sqlite3MinimumFileFormat(Parse *pParse, int iDb, int minFormat){
+  Vdbe *v;
+  v = sqlite3GetVdbe(pParse);
+  /* The VDBE should have been allocated before this routine is called.
+  ** If that allocation failed, we would have quit before reaching this
+  ** point */
+  if( ALWAYS(v) ){
+    int r1 = sqlite3GetTempReg(pParse);
+    int r2 = sqlite3GetTempReg(pParse);
+    int j1;
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
+    sqlite3VdbeUsesBtree(v, iDb);
+    sqlite3VdbeAddOp2(v, OP_Integer, minFormat, r2);
+    j1 = sqlite3VdbeAddOp3(v, OP_Ge, r2, 0, r1);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, r2);
+    sqlite3VdbeJumpHere(v, j1);
+    sqlite3ReleaseTempReg(pParse, r1);
+    sqlite3ReleaseTempReg(pParse, r2);
+  }
+}
+
 /*
 ** This function is called after an "ALTER TABLE ... ADD" statement
 ** has been parsed. Argument pColDef contains the text of the new
@@ -59789,7 +78013,7 @@ SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
   assert( sqlite3BtreeHoldsAllMutexes(db) );
   iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
   zDb = db->aDb[iDb].zName;
-  zTab = pNew->zName;
+  zTab = &pNew->zName[16];  /* Skip the "sqlite_altertab_" prefix on the name */
   pCol = &pNew->aCol[pNew->nCol-1];
   pDflt = pCol->pDflt;
   pTab = sqlite3FindTable(db, zTab, zDb);
@@ -59822,6 +78046,11 @@ SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
     sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
     return;
   }
+  if( (db->flags&SQLITE_ForeignKeys) && pNew->pFKey && pDflt ){
+    sqlite3ErrorMsg(pParse, 
+        "Cannot add a REFERENCES column with non-NULL default value");
+    return;
+  }
   if( pCol->notNull && !pDflt ){
     sqlite3ErrorMsg(pParse, 
         "Cannot add a NOT NULL column with default value NULL");
@@ -59848,9 +78077,11 @@ SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
   zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
   if( zCol ){
     char *zEnd = &zCol[pColDef->n-1];
-    while( (zEnd>zCol && *zEnd==';') || isspace(*(unsigned char *)zEnd) ){
+    int savedDbFlags = db->flags;
+    while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
       *zEnd-- = '\0';
     }
+    db->flags |= SQLITE_PreferBuiltin;
     sqlite3NestedParse(pParse, 
         "UPDATE \"%w\".%s SET "
           "sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
@@ -59859,6 +78090,7 @@ SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
       zTab
     );
     sqlite3DbFree(db, zCol);
+    db->flags = savedDbFlags;
   }
 
   /* If the default value of the new column is NULL, then set the file
@@ -59914,24 +78146,30 @@ SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
     sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
     goto exit_begin_add_column;
   }
+  if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
+    goto exit_begin_add_column;
+  }
 
   assert( pTab->addColOffset>0 );
   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
 
   /* Put a copy of the Table struct in Parse.pNewTable for the
-  ** sqlite3AddColumn() function and friends to modify.
+  ** sqlite3AddColumn() function and friends to modify.  But modify
+  ** the name by adding an "sqlite_altertab_" prefix.  By adding this
+  ** prefix, we insure that the name will not collide with an existing
+  ** table because user table are not allowed to have the "sqlite_"
+  ** prefix on their name.
   */
   pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
   if( !pNew ) goto exit_begin_add_column;
   pParse->pNewTable = pNew;
   pNew->nRef = 1;
-  pNew->db = db;
   pNew->nCol = pTab->nCol;
   assert( pNew->nCol>0 );
   nAlloc = (((pNew->nCol-1)/8)*8)+8;
   assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
   pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
-  pNew->zName = sqlite3DbStrDup(db, pTab->zName);
+  pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
   if( !pNew->aCol || !pNew->zName ){
     db->mallocFailed = 1;
     goto exit_begin_add_column;
@@ -59943,6 +78181,7 @@ SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
     pCol->zColl = 0;
     pCol->zType = 0;
     pCol->pDflt = 0;
+    pCol->zDflt = 0;
   }
   pNew->pSchema = db->aDb[iDb].pSchema;
   pNew->addColOffset = pTab->addColOffset;
@@ -59975,73 +78214,415 @@ exit_begin_add_column:
 *************************************************************************
 ** This file contains code associated with the ANALYZE command.
 **
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+** The ANALYZE command gather statistics about the content of tables
+** and indices.  These statistics are made available to the query planner
+** to help it make better decisions about how to perform queries.
+**
+** The following system tables are or have been supported:
+**
+**    CREATE TABLE sqlite_stat1(tbl, idx, stat);
+**    CREATE TABLE sqlite_stat2(tbl, idx, sampleno, sample);
+**    CREATE TABLE sqlite_stat3(tbl, idx, nEq, nLt, nDLt, sample);
+**
+** Additional tables might be added in future releases of SQLite.
+** The sqlite_stat2 table is not created or used unless the SQLite version
+** is between 3.6.18 and 3.7.8, inclusive, and unless SQLite is compiled
+** with SQLITE_ENABLE_STAT2.  The sqlite_stat2 table is deprecated.
+** The sqlite_stat2 table is superceded by sqlite_stat3, which is only
+** created and used by SQLite versions 3.7.9 and later and with
+** SQLITE_ENABLE_STAT3 defined.  The fucntionality of sqlite_stat3
+** is a superset of sqlite_stat2.  
+**
+** Format of sqlite_stat1:
+**
+** There is normally one row per index, with the index identified by the
+** name in the idx column.  The tbl column is the name of the table to
+** which the index belongs.  In each such row, the stat column will be
+** a string consisting of a list of integers.  The first integer in this
+** list is the number of rows in the index and in the table.  The second
+** integer is the average number of rows in the index that have the same
+** value in the first column of the index.  The third integer is the average
+** number of rows in the index that have the same value for the first two
+** columns.  The N-th integer (for N>1) is the average number of rows in 
+** the index which have the same value for the first N-1 columns.  For
+** a K-column index, there will be K+1 integers in the stat column.  If
+** the index is unique, then the last integer will be 1.
+**
+** The list of integers in the stat column can optionally be followed
+** by the keyword "unordered".  The "unordered" keyword, if it is present,
+** must be separated from the last integer by a single space.  If the
+** "unordered" keyword is present, then the query planner assumes that
+** the index is unordered and will not use the index for a range query.
+** 
+** If the sqlite_stat1.idx column is NULL, then the sqlite_stat1.stat
+** column contains a single integer which is the (estimated) number of
+** rows in the table identified by sqlite_stat1.tbl.
+**
+** Format of sqlite_stat2:
+**
+** The sqlite_stat2 is only created and is only used if SQLite is compiled
+** with SQLITE_ENABLE_STAT2 and if the SQLite version number is between
+** 3.6.18 and 3.7.8.  The "stat2" table contains additional information
+** about the distribution of keys within an index.  The index is identified by
+** the "idx" column and the "tbl" column is the name of the table to which
+** the index belongs.  There are usually 10 rows in the sqlite_stat2
+** table for each index.
+**
+** The sqlite_stat2 entries for an index that have sampleno between 0 and 9
+** inclusive are samples of the left-most key value in the index taken at
+** evenly spaced points along the index.  Let the number of samples be S
+** (10 in the standard build) and let C be the number of rows in the index.
+** Then the sampled rows are given by:
+**
+**     rownumber = (i*C*2 + C)/(S*2)
+**
+** For i between 0 and S-1.  Conceptually, the index space is divided into
+** S uniform buckets and the samples are the middle row from each bucket.
+**
+** The format for sqlite_stat2 is recorded here for legacy reference.  This
+** version of SQLite does not support sqlite_stat2.  It neither reads nor
+** writes the sqlite_stat2 table.  This version of SQLite only supports
+** sqlite_stat3.
+**
+** Format for sqlite_stat3:
+**
+** The sqlite_stat3 is an enhancement to sqlite_stat2.  A new name is
+** used to avoid compatibility problems.  
+**
+** The format of the sqlite_stat3 table is similar to the format of
+** the sqlite_stat2 table.  There are multiple entries for each index.
+** The idx column names the index and the tbl column is the table of the
+** index.  If the idx and tbl columns are the same, then the sample is
+** of the INTEGER PRIMARY KEY.  The sample column is a value taken from
+** the left-most column of the index.  The nEq column is the approximate
+** number of entires in the index whose left-most column exactly matches
+** the sample.  nLt is the approximate number of entires whose left-most
+** column is less than the sample.  The nDLt column is the approximate
+** number of distinct left-most entries in the index that are less than
+** the sample.
+**
+** Future versions of SQLite might change to store a string containing
+** multiple integers values in the nDLt column of sqlite_stat3.  The first
+** integer will be the number of prior index entires that are distinct in
+** the left-most column.  The second integer will be the number of prior index
+** entries that are distinct in the first two columns.  The third integer
+** will be the number of prior index entries that are distinct in the first
+** three columns.  And so forth.  With that extension, the nDLt field is
+** similar in function to the sqlite_stat1.stat field.
+**
+** There can be an arbitrary number of sqlite_stat3 entries per index.
+** The ANALYZE command will typically generate sqlite_stat3 tables
+** that contain between 10 and 40 samples which are distributed across
+** the key space, though not uniformly, and which include samples with
+** largest possible nEq values.
 */
 #ifndef SQLITE_OMIT_ANALYZE
 
 /*
-** This routine generates code that opens the sqlite_stat1 table on cursor
-** iStatCur.
+** This routine generates code that opens the sqlite_stat1 table for
+** writing with cursor iStatCur. If the library was built with the
+** SQLITE_ENABLE_STAT3 macro defined, then the sqlite_stat3 table is
+** opened for writing using cursor (iStatCur+1)
 **
 ** If the sqlite_stat1 tables does not previously exist, it is created.
-** If it does previously exist, all entires associated with table zWhere
-** are removed.  If zWhere==0 then all entries are removed.
+** Similarly, if the sqlite_stat3 table does not exist and the library
+** is compiled with SQLITE_ENABLE_STAT3 defined, it is created. 
+**
+** Argument zWhere may be a pointer to a buffer containing a table name,
+** or it may be a NULL pointer. If it is not NULL, then all entries in
+** the sqlite_stat1 and (if applicable) sqlite_stat3 tables associated
+** with the named table are deleted. If zWhere==0, then code is generated
+** to delete all stat table entries.
 */
 static void openStatTable(
   Parse *pParse,          /* Parsing context */
   int iDb,                /* The database we are looking in */
   int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
-  const char *zWhere      /* Delete entries associated with this table */
+  const char *zWhere,     /* Delete entries for this table or index */
+  const char *zWhereType  /* Either "tbl" or "idx" */
 ){
+  static const struct {
+    const char *zName;
+    const char *zCols;
+  } aTable[] = {
+    { "sqlite_stat1", "tbl,idx,stat" },
+#ifdef SQLITE_ENABLE_STAT3
+    { "sqlite_stat3", "tbl,idx,neq,nlt,ndlt,sample" },
+#endif
+  };
+
+  int aRoot[] = {0, 0};
+  u8 aCreateTbl[] = {0, 0};
+
+  int i;
   sqlite3 *db = pParse->db;
   Db *pDb;
-  int iRootPage;
-  u8 createStat1 = 0;
-  Table *pStat;
   Vdbe *v = sqlite3GetVdbe(pParse);
-
   if( v==0 ) return;
   assert( sqlite3BtreeHoldsAllMutexes(db) );
   assert( sqlite3VdbeDb(v)==db );
   pDb = &db->aDb[iDb];
-  if( (pStat = sqlite3FindTable(db, "sqlite_stat1", pDb->zName))==0 ){
-    /* The sqlite_stat1 tables does not exist.  Create it.  
-    ** Note that a side-effect of the CREATE TABLE statement is to leave
-    ** the rootpage of the new table in register pParse->regRoot.  This is
-    ** important because the OpenWrite opcode below will be needing it. */
-    sqlite3NestedParse(pParse,
-      "CREATE TABLE %Q.sqlite_stat1(tbl,idx,stat)",
-      pDb->zName
-    );
-    iRootPage = pParse->regRoot;
-    createStat1 = 1;  /* Cause rootpage to be taken from top of stack */
-  }else if( zWhere ){
-    /* The sqlite_stat1 table exists.  Delete all entries associated with
-    ** the table zWhere. */
-    sqlite3NestedParse(pParse,
-       "DELETE FROM %Q.sqlite_stat1 WHERE tbl=%Q",
-       pDb->zName, zWhere
-    );
-    iRootPage = pStat->tnum;
-  }else{
-    /* The sqlite_stat1 table already exists.  Delete all rows. */
-    iRootPage = pStat->tnum;
-    sqlite3VdbeAddOp2(v, OP_Clear, pStat->tnum, iDb);
+
+  /* Create new statistic tables if they do not exist, or clear them
+  ** if they do already exist.
+  */
+  for(i=0; i<ArraySize(aTable); i++){
+    const char *zTab = aTable[i].zName;
+    Table *pStat;
+    if( (pStat = sqlite3FindTable(db, zTab, pDb->zName))==0 ){
+      /* The sqlite_stat[12] table does not exist. Create it. Note that a 
+      ** side-effect of the CREATE TABLE statement is to leave the rootpage 
+      ** of the new table in register pParse->regRoot. This is important 
+      ** because the OpenWrite opcode below will be needing it. */
+      sqlite3NestedParse(pParse,
+          "CREATE TABLE %Q.%s(%s)", pDb->zName, zTab, aTable[i].zCols
+      );
+      aRoot[i] = pParse->regRoot;
+      aCreateTbl[i] = OPFLAG_P2ISREG;
+    }else{
+      /* The table already exists. If zWhere is not NULL, delete all entries 
+      ** associated with the table zWhere. If zWhere is NULL, delete the
+      ** entire contents of the table. */
+      aRoot[i] = pStat->tnum;
+      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
+      if( zWhere ){
+        sqlite3NestedParse(pParse,
+           "DELETE FROM %Q.%s WHERE %s=%Q", pDb->zName, zTab, zWhereType, zWhere
+        );
+      }else{
+        /* The sqlite_stat[12] table already exists.  Delete all rows. */
+        sqlite3VdbeAddOp2(v, OP_Clear, aRoot[i], iDb);
+      }
+    }
   }
 
-  /* Open the sqlite_stat1 table for writing. Unless it was created
-  ** by this vdbe program, lock it for writing at the shared-cache level. 
-  ** If this vdbe did create the sqlite_stat1 table, then it must have 
-  ** already obtained a schema-lock, making the write-lock redundant.
-  */
-  if( !createStat1 ){
-    sqlite3TableLock(pParse, iDb, iRootPage, 1, "sqlite_stat1");
+  /* Open the sqlite_stat[13] tables for writing. */
+  for(i=0; i<ArraySize(aTable); i++){
+    sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur+i, aRoot[i], iDb);
+    sqlite3VdbeChangeP4(v, -1, (char *)3, P4_INT32);
+    sqlite3VdbeChangeP5(v, aCreateTbl[i]);
   }
-  sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, 3);
-  sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur, iRootPage, iDb);
-  sqlite3VdbeChangeP5(v, createStat1);
 }
 
+/*
+** Recommended number of samples for sqlite_stat3
+*/
+#ifndef SQLITE_STAT3_SAMPLES
+# define SQLITE_STAT3_SAMPLES 24
+#endif
+
+/*
+** Three SQL functions - stat3_init(), stat3_push(), and stat3_pop() -
+** share an instance of the following structure to hold their state
+** information.
+*/
+typedef struct Stat3Accum Stat3Accum;
+struct Stat3Accum {
+  tRowcnt nRow;             /* Number of rows in the entire table */
+  tRowcnt nPSample;         /* How often to do a periodic sample */
+  int iMin;                 /* Index of entry with minimum nEq and hash */
+  int mxSample;             /* Maximum number of samples to accumulate */
+  int nSample;              /* Current number of samples */
+  u32 iPrn;                 /* Pseudo-random number used for sampling */
+  struct Stat3Sample {
+    i64 iRowid;                /* Rowid in main table of the key */
+    tRowcnt nEq;               /* sqlite_stat3.nEq */
+    tRowcnt nLt;               /* sqlite_stat3.nLt */
+    tRowcnt nDLt;              /* sqlite_stat3.nDLt */
+    u8 isPSample;              /* True if a periodic sample */
+    u32 iHash;                 /* Tiebreaker hash */
+  } *a;                     /* An array of samples */
+};
+
+#ifdef SQLITE_ENABLE_STAT3
+/*
+** Implementation of the stat3_init(C,S) SQL function.  The two parameters
+** are the number of rows in the table or index (C) and the number of samples
+** to accumulate (S).
+**
+** This routine allocates the Stat3Accum object.
+**
+** The return value is the Stat3Accum object (P).
+*/
+static void stat3Init(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  Stat3Accum *p;
+  tRowcnt nRow;
+  int mxSample;
+  int n;
+
+  UNUSED_PARAMETER(argc);
+  nRow = (tRowcnt)sqlite3_value_int64(argv[0]);
+  mxSample = sqlite3_value_int(argv[1]);
+  n = sizeof(*p) + sizeof(p->a[0])*mxSample;
+  p = sqlite3MallocZero( n );
+  if( p==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  p->a = (struct Stat3Sample*)&p[1];
+  p->nRow = nRow;
+  p->mxSample = mxSample;
+  p->nPSample = p->nRow/(mxSample/3+1) + 1;
+  sqlite3_randomness(sizeof(p->iPrn), &p->iPrn);
+  sqlite3_result_blob(context, p, sizeof(p), sqlite3_free);
+}
+static const FuncDef stat3InitFuncdef = {
+  2,                /* nArg */
+  SQLITE_UTF8,      /* iPrefEnc */
+  0,                /* flags */
+  0,                /* pUserData */
+  0,                /* pNext */
+  stat3Init,        /* xFunc */
+  0,                /* xStep */
+  0,                /* xFinalize */
+  "stat3_init",     /* zName */
+  0,                /* pHash */
+  0                 /* pDestructor */
+};
+
+
+/*
+** Implementation of the stat3_push(nEq,nLt,nDLt,rowid,P) SQL function.  The
+** arguments describe a single key instance.  This routine makes the 
+** decision about whether or not to retain this key for the sqlite_stat3
+** table.
+**
+** The return value is NULL.
+*/
+static void stat3Push(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  Stat3Accum *p = (Stat3Accum*)sqlite3_value_blob(argv[4]);
+  tRowcnt nEq = sqlite3_value_int64(argv[0]);
+  tRowcnt nLt = sqlite3_value_int64(argv[1]);
+  tRowcnt nDLt = sqlite3_value_int64(argv[2]);
+  i64 rowid = sqlite3_value_int64(argv[3]);
+  u8 isPSample = 0;
+  u8 doInsert = 0;
+  int iMin = p->iMin;
+  struct Stat3Sample *pSample;
+  int i;
+  u32 h;
+
+  UNUSED_PARAMETER(context);
+  UNUSED_PARAMETER(argc);
+  if( nEq==0 ) return;
+  h = p->iPrn = p->iPrn*1103515245 + 12345;
+  if( (nLt/p->nPSample)!=((nEq+nLt)/p->nPSample) ){
+    doInsert = isPSample = 1;
+  }else if( p->nSample<p->mxSample ){
+    doInsert = 1;
+  }else{
+    if( nEq>p->a[iMin].nEq || (nEq==p->a[iMin].nEq && h>p->a[iMin].iHash) ){
+      doInsert = 1;
+    }
+  }
+  if( !doInsert ) return;
+  if( p->nSample==p->mxSample ){
+    assert( p->nSample - iMin - 1 >= 0 );
+    memmove(&p->a[iMin], &p->a[iMin+1], sizeof(p->a[0])*(p->nSample-iMin-1));
+    pSample = &p->a[p->nSample-1];
+  }else{
+    pSample = &p->a[p->nSample++];
+  }
+  pSample->iRowid = rowid;
+  pSample->nEq = nEq;
+  pSample->nLt = nLt;
+  pSample->nDLt = nDLt;
+  pSample->iHash = h;
+  pSample->isPSample = isPSample;
+
+  /* Find the new minimum */
+  if( p->nSample==p->mxSample ){
+    pSample = p->a;
+    i = 0;
+    while( pSample->isPSample ){
+      i++;
+      pSample++;
+      assert( i<p->nSample );
+    }
+    nEq = pSample->nEq;
+    h = pSample->iHash;
+    iMin = i;
+    for(i++, pSample++; i<p->nSample; i++, pSample++){
+      if( pSample->isPSample ) continue;
+      if( pSample->nEq<nEq
+       || (pSample->nEq==nEq && pSample->iHash<h)
+      ){
+        iMin = i;
+        nEq = pSample->nEq;
+        h = pSample->iHash;
+      }
+    }
+    p->iMin = iMin;
+  }
+}
+static const FuncDef stat3PushFuncdef = {
+  5,                /* nArg */
+  SQLITE_UTF8,      /* iPrefEnc */
+  0,                /* flags */
+  0,                /* pUserData */
+  0,                /* pNext */
+  stat3Push,        /* xFunc */
+  0,                /* xStep */
+  0,                /* xFinalize */
+  "stat3_push",     /* zName */
+  0,                /* pHash */
+  0                 /* pDestructor */
+};
+
+/*
+** Implementation of the stat3_get(P,N,...) SQL function.  This routine is
+** used to query the results.  Content is returned for the Nth sqlite_stat3
+** row where N is between 0 and S-1 and S is the number of samples.  The
+** value returned depends on the number of arguments.
+**
+**   argc==2    result:  rowid
+**   argc==3    result:  nEq
+**   argc==4    result:  nLt
+**   argc==5    result:  nDLt
+*/
+static void stat3Get(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int n = sqlite3_value_int(argv[1]);
+  Stat3Accum *p = (Stat3Accum*)sqlite3_value_blob(argv[0]);
+
+  assert( p!=0 );
+  if( p->nSample<=n ) return;
+  switch( argc ){
+    case 2:  sqlite3_result_int64(context, p->a[n].iRowid); break;
+    case 3:  sqlite3_result_int64(context, p->a[n].nEq);    break;
+    case 4:  sqlite3_result_int64(context, p->a[n].nLt);    break;
+    default: sqlite3_result_int64(context, p->a[n].nDLt);   break;
+  }
+}
+static const FuncDef stat3GetFuncdef = {
+  -1,               /* nArg */
+  SQLITE_UTF8,      /* iPrefEnc */
+  0,                /* flags */
+  0,                /* pUserData */
+  0,                /* pNext */
+  stat3Get,         /* xFunc */
+  0,                /* xStep */
+  0,                /* xFinalize */
+  "stat3_get",     /* zName */
+  0,                /* pHash */
+  0                 /* pDestructor */
+};
+#endif /* SQLITE_ENABLE_STAT3 */
+
+
+
+
 /*
 ** Generate code to do an analysis of all indices associated with
 ** a single table.
@@ -60049,30 +78630,62 @@ static void openStatTable(
 static void analyzeOneTable(
   Parse *pParse,   /* Parser context */
   Table *pTab,     /* Table whose indices are to be analyzed */
+  Index *pOnlyIdx, /* If not NULL, only analyze this one index */
   int iStatCur,    /* Index of VdbeCursor that writes the sqlite_stat1 table */
   int iMem         /* Available memory locations begin here */
 ){
-  Index *pIdx;     /* An index to being analyzed */
-  int iIdxCur;     /* Index of VdbeCursor for index being analyzed */
-  int nCol;        /* Number of columns in the index */
-  Vdbe *v;         /* The virtual machine being built up */
-  int i;           /* Loop counter */
-  int topOfLoop;   /* The top of the loop */
-  int endOfLoop;   /* The end of the loop */
-  int addr;        /* The address of an instruction */
-  int iDb;         /* Index of database containing pTab */
+  sqlite3 *db = pParse->db;    /* Database handle */
+  Index *pIdx;                 /* An index to being analyzed */
+  int iIdxCur;                 /* Cursor open on index being analyzed */
+  Vdbe *v;                     /* The virtual machine being built up */
+  int i;                       /* Loop counter */
+  int topOfLoop;               /* The top of the loop */
+  int endOfLoop;               /* The end of the loop */
+  int jZeroRows = -1;          /* Jump from here if number of rows is zero */
+  int iDb;                     /* Index of database containing pTab */
+  int regTabname = iMem++;     /* Register containing table name */
+  int regIdxname = iMem++;     /* Register containing index name */
+  int regStat1 = iMem++;       /* The stat column of sqlite_stat1 */
+#ifdef SQLITE_ENABLE_STAT3
+  int regNumEq = regStat1;     /* Number of instances.  Same as regStat1 */
+  int regNumLt = iMem++;       /* Number of keys less than regSample */
+  int regNumDLt = iMem++;      /* Number of distinct keys less than regSample */
+  int regSample = iMem++;      /* The next sample value */
+  int regRowid = regSample;    /* Rowid of a sample */
+  int regAccum = iMem++;       /* Register to hold Stat3Accum object */
+  int regLoop = iMem++;        /* Loop counter */
+  int regCount = iMem++;       /* Number of rows in the table or index */
+  int regTemp1 = iMem++;       /* Intermediate register */
+  int regTemp2 = iMem++;       /* Intermediate register */
+  int once = 1;                /* One-time initialization */
+  int shortJump = 0;           /* Instruction address */
+  int iTabCur = pParse->nTab++; /* Table cursor */
+#endif
+  int regCol = iMem++;         /* Content of a column in analyzed table */
+  int regRec = iMem++;         /* Register holding completed record */
+  int regTemp = iMem++;        /* Temporary use register */
+  int regNewRowid = iMem++;    /* Rowid for the inserted record */
+
 
   v = sqlite3GetVdbe(pParse);
-  if( v==0 || pTab==0 || pTab->pIndex==0 ){
-    /* Do no analysis for tables that have no indices */
+  if( v==0 || NEVER(pTab==0) ){
     return;
   }
-  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
-  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  if( pTab->tnum==0 ){
+    /* Do not gather statistics on views or virtual tables */
+    return;
+  }
+  if( memcmp(pTab->zName, "sqlite_", 7)==0 ){
+    /* Do not gather statistics on system tables */
+    return;
+  }
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
   assert( iDb>=0 );
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
 #ifndef SQLITE_OMIT_AUTHORIZATION
   if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0,
-      pParse->db->aDb[iDb].zName ) ){
+      db->aDb[iDb].zName ) ){
     return;
   }
 #endif
@@ -60080,43 +78693,64 @@ static void analyzeOneTable(
   /* Establish a read-lock on the table at the shared-cache level. */
   sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
 
-  iIdxCur = pParse->nTab;
+  iIdxCur = pParse->nTab++;
+  sqlite3VdbeAddOp4(v, OP_String8, 0, regTabname, 0, pTab->zName, 0);
   for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
-    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
-    int regFields;    /* Register block for building records */
-    int regRec;       /* Register holding completed record */
-    int regTemp;      /* Temporary use register */
-    int regCol;       /* Content of a column from the table being analyzed */
-    int regRowid;     /* Rowid for the inserted record */
-    int regF2;
+    int nCol;
+    KeyInfo *pKey;
+    int addrIfNot = 0;           /* address of OP_IfNot */
+    int *aChngAddr;              /* Array of jump instruction addresses */
 
-    /* Open a cursor to the index to be analyzed
-    */
-    assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
+    if( pOnlyIdx && pOnlyIdx!=pIdx ) continue;
+    VdbeNoopComment((v, "Begin analysis of %s", pIdx->zName));
     nCol = pIdx->nColumn;
-    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, nCol+1);
+    aChngAddr = sqlite3DbMallocRaw(db, sizeof(int)*nCol);
+    if( aChngAddr==0 ) continue;
+    pKey = sqlite3IndexKeyinfo(pParse, pIdx);
+    if( iMem+1+(nCol*2)>pParse->nMem ){
+      pParse->nMem = iMem+1+(nCol*2);
+    }
+
+    /* Open a cursor to the index to be analyzed. */
+    assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) );
     sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb,
         (char *)pKey, P4_KEYINFO_HANDOFF);
     VdbeComment((v, "%s", pIdx->zName));
-    regFields = iMem+nCol*2;
-    regTemp = regRowid = regCol = regFields+3;
-    regRec = regCol+1;
-    if( regRec>pParse->nMem ){
-      pParse->nMem = regRec;
-    }
 
-    /* Memory cells are used as follows:
+    /* Populate the register containing the index name. */
+    sqlite3VdbeAddOp4(v, OP_String8, 0, regIdxname, 0, pIdx->zName, 0);
+
+#ifdef SQLITE_ENABLE_STAT3
+    if( once ){
+      once = 0;
+      sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
+    }
+    sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regCount);
+    sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_STAT3_SAMPLES, regTemp1);
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regNumEq);
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regNumLt);
+    sqlite3VdbeAddOp2(v, OP_Integer, -1, regNumDLt);
+    sqlite3VdbeAddOp3(v, OP_Null, 0, regSample, regAccum);
+    sqlite3VdbeAddOp4(v, OP_Function, 1, regCount, regAccum,
+                      (char*)&stat3InitFuncdef, P4_FUNCDEF);
+    sqlite3VdbeChangeP5(v, 2);
+#endif /* SQLITE_ENABLE_STAT3 */
+
+    /* The block of memory cells initialized here is used as follows.
     **
-    **    mem[iMem]:             The total number of rows in the table.
-    **    mem[iMem+1]:           Number of distinct values in column 1
-    **    ...
-    **    mem[iMem+nCol]:        Number of distinct values in column N
-    **    mem[iMem+nCol+1]       Last observed value of column 1
-    **    ...
-    **    mem[iMem+nCol+nCol]:   Last observed value of column N
+    **    iMem:                
+    **        The total number of rows in the table.
     **
-    ** Cells iMem through iMem+nCol are initialized to 0.  The others
-    ** are initialized to NULL.
+    **    iMem+1 .. iMem+nCol: 
+    **        Number of distinct entries in index considering the 
+    **        left-most N columns only, where N is between 1 and nCol, 
+    **        inclusive.
+    **
+    **    iMem+nCol+1 .. Mem+2*nCol:  
+    **        Previous value of indexed columns, from left to right.
+    **
+    ** Cells iMem through iMem+nCol are initialized to 0. The others are 
+    ** initialized to contain an SQL NULL.
     */
     for(i=0; i<=nCol; i++){
       sqlite3VdbeAddOp2(v, OP_Integer, 0, iMem+i);
@@ -60125,34 +78759,95 @@ static void analyzeOneTable(
       sqlite3VdbeAddOp2(v, OP_Null, 0, iMem+nCol+i+1);
     }
 
-    /* Do the analysis.
-    */
+    /* Start the analysis loop. This loop runs through all the entries in
+    ** the index b-tree.  */
     endOfLoop = sqlite3VdbeMakeLabel(v);
     sqlite3VdbeAddOp2(v, OP_Rewind, iIdxCur, endOfLoop);
     topOfLoop = sqlite3VdbeCurrentAddr(v);
-    sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1);
+    sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1);  /* Increment row counter */
+
     for(i=0; i<nCol; i++){
+      CollSeq *pColl;
       sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regCol);
-      sqlite3VdbeAddOp3(v, OP_Ne, regCol, 0, iMem+nCol+i+1);
-      /**** TODO:  add collating sequence *****/
-      sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
+      if( i==0 ){
+        /* Always record the very first row */
+        addrIfNot = sqlite3VdbeAddOp1(v, OP_IfNot, iMem+1);
+      }
+      assert( pIdx->azColl!=0 );
+      assert( pIdx->azColl[i]!=0 );
+      pColl = sqlite3LocateCollSeq(pParse, pIdx->azColl[i]);
+      aChngAddr[i] = sqlite3VdbeAddOp4(v, OP_Ne, regCol, 0, iMem+nCol+i+1,
+                                      (char*)pColl, P4_COLLSEQ);
+      sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+      VdbeComment((v, "jump if column %d changed", i));
+#ifdef SQLITE_ENABLE_STAT3
+      if( i==0 ){
+        sqlite3VdbeAddOp2(v, OP_AddImm, regNumEq, 1);
+        VdbeComment((v, "incr repeat count"));
+      }
+#endif
     }
     sqlite3VdbeAddOp2(v, OP_Goto, 0, endOfLoop);
     for(i=0; i<nCol; i++){
-      sqlite3VdbeJumpHere(v, topOfLoop + 2*(i + 1));
+      sqlite3VdbeJumpHere(v, aChngAddr[i]);  /* Set jump dest for the OP_Ne */
+      if( i==0 ){
+        sqlite3VdbeJumpHere(v, addrIfNot);   /* Jump dest for OP_IfNot */
+#ifdef SQLITE_ENABLE_STAT3
+        sqlite3VdbeAddOp4(v, OP_Function, 1, regNumEq, regTemp2,
+                          (char*)&stat3PushFuncdef, P4_FUNCDEF);
+        sqlite3VdbeChangeP5(v, 5);
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, pIdx->nColumn, regRowid);
+        sqlite3VdbeAddOp3(v, OP_Add, regNumEq, regNumLt, regNumLt);
+        sqlite3VdbeAddOp2(v, OP_AddImm, regNumDLt, 1);
+        sqlite3VdbeAddOp2(v, OP_Integer, 1, regNumEq);
+#endif        
+      }
       sqlite3VdbeAddOp2(v, OP_AddImm, iMem+i+1, 1);
       sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, iMem+nCol+i+1);
     }
+    sqlite3DbFree(db, aChngAddr);
+
+    /* Always jump here after updating the iMem+1...iMem+1+nCol counters */
     sqlite3VdbeResolveLabel(v, endOfLoop);
+
     sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, topOfLoop);
     sqlite3VdbeAddOp1(v, OP_Close, iIdxCur);
+#ifdef SQLITE_ENABLE_STAT3
+    sqlite3VdbeAddOp4(v, OP_Function, 1, regNumEq, regTemp2,
+                      (char*)&stat3PushFuncdef, P4_FUNCDEF);
+    sqlite3VdbeChangeP5(v, 5);
+    sqlite3VdbeAddOp2(v, OP_Integer, -1, regLoop);
+    shortJump = 
+    sqlite3VdbeAddOp2(v, OP_AddImm, regLoop, 1);
+    sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regTemp1,
+                      (char*)&stat3GetFuncdef, P4_FUNCDEF);
+    sqlite3VdbeChangeP5(v, 2);
+    sqlite3VdbeAddOp1(v, OP_IsNull, regTemp1);
+    sqlite3VdbeAddOp3(v, OP_NotExists, iTabCur, shortJump, regTemp1);
+    sqlite3VdbeAddOp3(v, OP_Column, iTabCur, pIdx->aiColumn[0], regSample);
+    sqlite3ColumnDefault(v, pTab, pIdx->aiColumn[0], regSample);
+    sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regNumEq,
+                      (char*)&stat3GetFuncdef, P4_FUNCDEF);
+    sqlite3VdbeChangeP5(v, 3);
+    sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regNumLt,
+                      (char*)&stat3GetFuncdef, P4_FUNCDEF);
+    sqlite3VdbeChangeP5(v, 4);
+    sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regNumDLt,
+                      (char*)&stat3GetFuncdef, P4_FUNCDEF);
+    sqlite3VdbeChangeP5(v, 5);
+    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 6, regRec, "bbbbbb", 0);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regNewRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regRec, regNewRowid);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, shortJump);
+    sqlite3VdbeJumpHere(v, shortJump+2);
+#endif        
 
-    /* Store the results.  
+    /* Store the results in sqlite_stat1.
     **
     ** The result is a single row of the sqlite_stat1 table.  The first
     ** two columns are the names of the table and index.  The third column
     ** is a string composed of a list of integer statistics about the
-    ** index.  The first integer in the list is the total number of entires
+    ** index.  The first integer in the list is the total number of entries
     ** in the index.  There is one additional integer in the list for each
     ** column of the table.  This additional integer is a guess of how many
     ** rows of the table the index will select.  If D is the count of distinct
@@ -60165,31 +78860,51 @@ static void analyzeOneTable(
     ** If K>0 then it is always the case the D>0 so division by zero
     ** is never possible.
     */
-    addr = sqlite3VdbeAddOp1(v, OP_IfNot, iMem);
-    sqlite3VdbeAddOp4(v, OP_String8, 0, regFields, 0, pTab->zName, 0);
-    sqlite3VdbeAddOp4(v, OP_String8, 0, regFields+1, 0, pIdx->zName, 0);
-    regF2 = regFields+2;
-    sqlite3VdbeAddOp2(v, OP_SCopy, iMem, regF2);
+    sqlite3VdbeAddOp2(v, OP_SCopy, iMem, regStat1);
+    if( jZeroRows<0 ){
+      jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, iMem);
+    }
     for(i=0; i<nCol; i++){
       sqlite3VdbeAddOp4(v, OP_String8, 0, regTemp, 0, " ", 0);
-      sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regF2, regF2);
+      sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regStat1, regStat1);
       sqlite3VdbeAddOp3(v, OP_Add, iMem, iMem+i+1, regTemp);
       sqlite3VdbeAddOp2(v, OP_AddImm, regTemp, -1);
       sqlite3VdbeAddOp3(v, OP_Divide, iMem+i+1, regTemp, regTemp);
       sqlite3VdbeAddOp1(v, OP_ToInt, regTemp);
-      sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regF2, regF2);
+      sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regStat1, regStat1);
     }
-    sqlite3VdbeAddOp4(v, OP_MakeRecord, regFields, 3, regRec, "aaa", 0);
-    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regRowid);
-    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regRowid);
+    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regRec, "aaa", 0);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regNewRowid);
     sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
-    sqlite3VdbeJumpHere(v, addr);
   }
+
+  /* If the table has no indices, create a single sqlite_stat1 entry
+  ** containing NULL as the index name and the row count as the content.
+  */
+  if( pTab->pIndex==0 ){
+    sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pTab->tnum, iDb);
+    VdbeComment((v, "%s", pTab->zName));
+    sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat1);
+    sqlite3VdbeAddOp1(v, OP_Close, iIdxCur);
+    jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1);
+  }else{
+    sqlite3VdbeJumpHere(v, jZeroRows);
+    jZeroRows = sqlite3VdbeAddOp0(v, OP_Goto);
+  }
+  sqlite3VdbeAddOp2(v, OP_Null, 0, regIdxname);
+  sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regRec, "aaa", 0);
+  sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
+  sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regNewRowid);
+  sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+  if( pParse->nMem<regRec ) pParse->nMem = regRec;
+  sqlite3VdbeJumpHere(v, jZeroRows);
 }
 
+
 /*
 ** Generate code that will cause the most recent index analysis to
-** be laoded into internal hash tables where is can be used.
+** be loaded into internal hash tables where is can be used.
 */
 static void loadAnalysis(Parse *pParse, int iDb){
   Vdbe *v = sqlite3GetVdbe(pParse);
@@ -60209,21 +78924,24 @@ static void analyzeDatabase(Parse *pParse, int iDb){
   int iMem;
 
   sqlite3BeginWriteOperation(pParse, 0, iDb);
-  iStatCur = pParse->nTab++;
-  openStatTable(pParse, iDb, iStatCur, 0);
+  iStatCur = pParse->nTab;
+  pParse->nTab += 3;
+  openStatTable(pParse, iDb, iStatCur, 0, 0);
   iMem = pParse->nMem+1;
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
   for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
     Table *pTab = (Table*)sqliteHashData(k);
-    analyzeOneTable(pParse, pTab, iStatCur, iMem);
+    analyzeOneTable(pParse, pTab, 0, iStatCur, iMem);
   }
   loadAnalysis(pParse, iDb);
 }
 
 /*
 ** Generate code that will do an analysis of a single table in
-** a database.
+** a database.  If pOnlyIdx is not NULL then it is a single index
+** in pTab that should be analyzed.
 */
-static void analyzeTable(Parse *pParse, Table *pTab){
+static void analyzeTable(Parse *pParse, Table *pTab, Index *pOnlyIdx){
   int iDb;
   int iStatCur;
 
@@ -60231,9 +78949,14 @@ static void analyzeTable(Parse *pParse, Table *pTab){
   assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
   sqlite3BeginWriteOperation(pParse, 0, iDb);
-  iStatCur = pParse->nTab++;
-  openStatTable(pParse, iDb, iStatCur, pTab->zName);
-  analyzeOneTable(pParse, pTab, iStatCur, pParse->nMem+1);
+  iStatCur = pParse->nTab;
+  pParse->nTab += 3;
+  if( pOnlyIdx ){
+    openStatTable(pParse, iDb, iStatCur, pOnlyIdx->zName, "idx");
+  }else{
+    openStatTable(pParse, iDb, iStatCur, pTab->zName, "tbl");
+  }
+  analyzeOneTable(pParse, pTab, pOnlyIdx, iStatCur, pParse->nMem+1);
   loadAnalysis(pParse, iDb);
 }
 
@@ -60255,6 +78978,7 @@ SQLITE_PRIVATE void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
   int i;
   char *z, *zDb;
   Table *pTab;
+  Index *pIdx;
   Token *pTableName;
 
   /* Read the database schema. If an error occurs, leave an error message
@@ -60264,13 +78988,14 @@ SQLITE_PRIVATE void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
     return;
   }
 
+  assert( pName2!=0 || pName1==0 );
   if( pName1==0 ){
     /* Form 1:  Analyze everything */
     for(i=0; i<db->nDb; i++){
       if( i==1 ) continue;  /* Do not analyze the TEMP database */
       analyzeDatabase(pParse, i);
     }
-  }else if( pName2==0 || pName2->n==0 ){
+  }else if( pName2->n==0 ){
     /* Form 2:  Analyze the database or table named */
     iDb = sqlite3FindDb(db, pName1);
     if( iDb>=0 ){
@@ -60278,11 +79003,12 @@ SQLITE_PRIVATE void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
     }else{
       z = sqlite3NameFromToken(db, pName1);
       if( z ){
-        pTab = sqlite3LocateTable(pParse, 0, z, 0);
-        sqlite3DbFree(db, z);
-        if( pTab ){
-          analyzeTable(pParse, pTab);
+        if( (pIdx = sqlite3FindIndex(db, z, 0))!=0 ){
+          analyzeTable(pParse, pIdx->pTable, pIdx);
+        }else if( (pTab = sqlite3LocateTable(pParse, 0, z, 0))!=0 ){
+          analyzeTable(pParse, pTab, 0);
         }
+        sqlite3DbFree(db, z);
       }
     }
   }else{
@@ -60292,11 +79018,12 @@ SQLITE_PRIVATE void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
       zDb = db->aDb[iDb].zName;
       z = sqlite3NameFromToken(db, pTableName);
       if( z ){
-        pTab = sqlite3LocateTable(pParse, 0, z, zDb);
-        sqlite3DbFree(db, z);
-        if( pTab ){
-          analyzeTable(pParse, pTab);
+        if( (pIdx = sqlite3FindIndex(db, z, zDb))!=0 ){
+          analyzeTable(pParse, pIdx->pTable, pIdx);
+        }else if( (pTab = sqlite3LocateTable(pParse, 0, z, zDb))!=0 ){
+          analyzeTable(pParse, pTab, 0);
         }
+        sqlite3DbFree(db, z);
       }
     }   
   }
@@ -60316,41 +79043,230 @@ struct analysisInfo {
 ** This callback is invoked once for each index when reading the
 ** sqlite_stat1 table.  
 **
-**     argv[0] = name of the index
-**     argv[1] = results of analysis - on integer for each column
+**     argv[0] = name of the table
+**     argv[1] = name of the index (might be NULL)
+**     argv[2] = results of analysis - on integer for each column
+**
+** Entries for which argv[1]==NULL simply record the number of rows in
+** the table.
 */
 static int analysisLoader(void *pData, int argc, char **argv, char **NotUsed){
   analysisInfo *pInfo = (analysisInfo*)pData;
   Index *pIndex;
-  int i, c;
-  unsigned int v;
+  Table *pTable;
+  int i, c, n;
+  tRowcnt v;
   const char *z;
 
-  assert( argc==2 );
+  assert( argc==3 );
   UNUSED_PARAMETER2(NotUsed, argc);
 
-  if( argv==0 || argv[0]==0 || argv[1]==0 ){
+  if( argv==0 || argv[0]==0 || argv[2]==0 ){
     return 0;
   }
-  pIndex = sqlite3FindIndex(pInfo->db, argv[0], pInfo->zDatabase);
-  if( pIndex==0 ){
+  pTable = sqlite3FindTable(pInfo->db, argv[0], pInfo->zDatabase);
+  if( pTable==0 ){
     return 0;
   }
-  z = argv[1];
-  for(i=0; *z && i<=pIndex->nColumn; i++){
+  if( argv[1] ){
+    pIndex = sqlite3FindIndex(pInfo->db, argv[1], pInfo->zDatabase);
+  }else{
+    pIndex = 0;
+  }
+  n = pIndex ? pIndex->nColumn : 0;
+  z = argv[2];
+  for(i=0; *z && i<=n; i++){
     v = 0;
     while( (c=z[0])>='0' && c<='9' ){
       v = v*10 + c - '0';
       z++;
     }
+    if( i==0 ) pTable->nRowEst = v;
+    if( pIndex==0 ) break;
     pIndex->aiRowEst[i] = v;
     if( *z==' ' ) z++;
+    if( memcmp(z, "unordered", 10)==0 ){
+      pIndex->bUnordered = 1;
+      break;
+    }
   }
   return 0;
 }
 
 /*
-** Load the content of the sqlite_stat1 table into the index hash tables.
+** If the Index.aSample variable is not NULL, delete the aSample[] array
+** and its contents.
+*/
+SQLITE_PRIVATE void sqlite3DeleteIndexSamples(sqlite3 *db, Index *pIdx){
+#ifdef SQLITE_ENABLE_STAT3
+  if( pIdx->aSample ){
+    int j;
+    for(j=0; j<pIdx->nSample; j++){
+      IndexSample *p = &pIdx->aSample[j];
+      if( p->eType==SQLITE_TEXT || p->eType==SQLITE_BLOB ){
+        sqlite3DbFree(db, p->u.z);
+      }
+    }
+    sqlite3DbFree(db, pIdx->aSample);
+  }
+  if( db && db->pnBytesFreed==0 ){
+    pIdx->nSample = 0;
+    pIdx->aSample = 0;
+  }
+#else
+  UNUSED_PARAMETER(db);
+  UNUSED_PARAMETER(pIdx);
+#endif
+}
+
+#ifdef SQLITE_ENABLE_STAT3
+/*
+** Load content from the sqlite_stat3 table into the Index.aSample[]
+** arrays of all indices.
+*/
+static int loadStat3(sqlite3 *db, const char *zDb){
+  int rc;                       /* Result codes from subroutines */
+  sqlite3_stmt *pStmt = 0;      /* An SQL statement being run */
+  char *zSql;                   /* Text of the SQL statement */
+  Index *pPrevIdx = 0;          /* Previous index in the loop */
+  int idx = 0;                  /* slot in pIdx->aSample[] for next sample */
+  int eType;                    /* Datatype of a sample */
+  IndexSample *pSample;         /* A slot in pIdx->aSample[] */
+
+  assert( db->lookaside.bEnabled==0 );
+  if( !sqlite3FindTable(db, "sqlite_stat3", zDb) ){
+    return SQLITE_OK;
+  }
+
+  zSql = sqlite3MPrintf(db, 
+      "SELECT idx,count(*) FROM %Q.sqlite_stat3"
+      " GROUP BY idx", zDb);
+  if( !zSql ){
+    return SQLITE_NOMEM;
+  }
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  sqlite3DbFree(db, zSql);
+  if( rc ) return rc;
+
+  while( sqlite3_step(pStmt)==SQLITE_ROW ){
+    char *zIndex;   /* Index name */
+    Index *pIdx;    /* Pointer to the index object */
+    int nSample;    /* Number of samples */
+
+    zIndex = (char *)sqlite3_column_text(pStmt, 0);
+    if( zIndex==0 ) continue;
+    nSample = sqlite3_column_int(pStmt, 1);
+    pIdx = sqlite3FindIndex(db, zIndex, zDb);
+    if( pIdx==0 ) continue;
+    assert( pIdx->nSample==0 );
+    pIdx->nSample = nSample;
+    pIdx->aSample = sqlite3DbMallocZero(db, nSample*sizeof(IndexSample));
+    pIdx->avgEq = pIdx->aiRowEst[1];
+    if( pIdx->aSample==0 ){
+      db->mallocFailed = 1;
+      sqlite3_finalize(pStmt);
+      return SQLITE_NOMEM;
+    }
+  }
+  rc = sqlite3_finalize(pStmt);
+  if( rc ) return rc;
+
+  zSql = sqlite3MPrintf(db, 
+      "SELECT idx,neq,nlt,ndlt,sample FROM %Q.sqlite_stat3", zDb);
+  if( !zSql ){
+    return SQLITE_NOMEM;
+  }
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  sqlite3DbFree(db, zSql);
+  if( rc ) return rc;
+
+  while( sqlite3_step(pStmt)==SQLITE_ROW ){
+    char *zIndex;   /* Index name */
+    Index *pIdx;    /* Pointer to the index object */
+    int i;          /* Loop counter */
+    tRowcnt sumEq;  /* Sum of the nEq values */
+
+    zIndex = (char *)sqlite3_column_text(pStmt, 0);
+    if( zIndex==0 ) continue;
+    pIdx = sqlite3FindIndex(db, zIndex, zDb);
+    if( pIdx==0 ) continue;
+    if( pIdx==pPrevIdx ){
+      idx++;
+    }else{
+      pPrevIdx = pIdx;
+      idx = 0;
+    }
+    assert( idx<pIdx->nSample );
+    pSample = &pIdx->aSample[idx];
+    pSample->nEq = (tRowcnt)sqlite3_column_int64(pStmt, 1);
+    pSample->nLt = (tRowcnt)sqlite3_column_int64(pStmt, 2);
+    pSample->nDLt = (tRowcnt)sqlite3_column_int64(pStmt, 3);
+    if( idx==pIdx->nSample-1 ){
+      if( pSample->nDLt>0 ){
+        for(i=0, sumEq=0; i<=idx-1; i++) sumEq += pIdx->aSample[i].nEq;
+        pIdx->avgEq = (pSample->nLt - sumEq)/pSample->nDLt;
+      }
+      if( pIdx->avgEq<=0 ) pIdx->avgEq = 1;
+    }
+    eType = sqlite3_column_type(pStmt, 4);
+    pSample->eType = (u8)eType;
+    switch( eType ){
+      case SQLITE_INTEGER: {
+        pSample->u.i = sqlite3_column_int64(pStmt, 4);
+        break;
+      }
+      case SQLITE_FLOAT: {
+        pSample->u.r = sqlite3_column_double(pStmt, 4);
+        break;
+      }
+      case SQLITE_NULL: {
+        break;
+      }
+      default: assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB ); {
+        const char *z = (const char *)(
+              (eType==SQLITE_BLOB) ?
+              sqlite3_column_blob(pStmt, 4):
+              sqlite3_column_text(pStmt, 4)
+           );
+        int n = z ? sqlite3_column_bytes(pStmt, 4) : 0;
+        pSample->nByte = n;
+        if( n < 1){
+          pSample->u.z = 0;
+        }else{
+          pSample->u.z = sqlite3DbMallocRaw(db, n);
+          if( pSample->u.z==0 ){
+            db->mallocFailed = 1;
+            sqlite3_finalize(pStmt);
+            return SQLITE_NOMEM;
+          }
+          memcpy(pSample->u.z, z, n);
+        }
+      }
+    }
+  }
+  return sqlite3_finalize(pStmt);
+}
+#endif /* SQLITE_ENABLE_STAT3 */
+
+/*
+** Load the content of the sqlite_stat1 and sqlite_stat3 tables. The
+** contents of sqlite_stat1 are used to populate the Index.aiRowEst[]
+** arrays. The contents of sqlite_stat3 are used to populate the
+** Index.aSample[] arrays.
+**
+** If the sqlite_stat1 table is not present in the database, SQLITE_ERROR
+** is returned. In this case, even if SQLITE_ENABLE_STAT3 was defined 
+** during compilation and the sqlite_stat3 table is present, no data is 
+** read from it.
+**
+** If SQLITE_ENABLE_STAT3 was defined during compilation and the 
+** sqlite_stat3 table is not present in the database, SQLITE_ERROR is
+** returned. However, in this case, data is read from the sqlite_stat1
+** table (if it is present) before returning.
+**
+** If an OOM error occurs, this function always sets db->mallocFailed.
+** This means if the caller does not care about other errors, the return
+** code may be ignored.
 */
 SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
   analysisInfo sInfo;
@@ -60360,29 +79276,49 @@ SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
 
   assert( iDb>=0 && iDb<db->nDb );
   assert( db->aDb[iDb].pBt!=0 );
-  assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
 
   /* Clear any prior statistics */
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
   for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
     Index *pIdx = sqliteHashData(i);
     sqlite3DefaultRowEst(pIdx);
+#ifdef SQLITE_ENABLE_STAT3
+    sqlite3DeleteIndexSamples(db, pIdx);
+    pIdx->aSample = 0;
+#endif
   }
 
-  /* Check to make sure the sqlite_stat1 table existss */
+  /* Check to make sure the sqlite_stat1 table exists */
   sInfo.db = db;
   sInfo.zDatabase = db->aDb[iDb].zName;
   if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){
-     return SQLITE_ERROR;
+    return SQLITE_ERROR;
+  }
+
+  /* Load new statistics out of the sqlite_stat1 table */
+  zSql = sqlite3MPrintf(db, 
+      "SELECT tbl,idx,stat FROM %Q.sqlite_stat1", sInfo.zDatabase);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
+    sqlite3DbFree(db, zSql);
   }
 
 
-  /* Load new statistics out of the sqlite_stat1 table */
-  zSql = sqlite3MPrintf(db, "SELECT idx, stat FROM %Q.sqlite_stat1",
-                        sInfo.zDatabase);
-  (void)sqlite3SafetyOff(db);
-  rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
-  (void)sqlite3SafetyOn(db);
-  sqlite3DbFree(db, zSql);
+  /* Load the statistics from the sqlite_stat3 table. */
+#ifdef SQLITE_ENABLE_STAT3
+  if( rc==SQLITE_OK ){
+    int lookasideEnabled = db->lookaside.bEnabled;
+    db->lookaside.bEnabled = 0;
+    rc = loadStat3(db, sInfo.zDatabase);
+    db->lookaside.bEnabled = lookasideEnabled;
+  }
+#endif
+
+  if( rc==SQLITE_NOMEM ){
+    db->mallocFailed = 1;
+  }
   return rc;
 }
 
@@ -60403,8 +79339,6 @@ SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
 **
 *************************************************************************
 ** This file contains code used to implement the ATTACH and DETACH commands.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 #ifndef SQLITE_OMIT_ATTACH
@@ -60433,7 +79367,7 @@ static int resolveAttachExpr(NameContext *pName, Expr *pExpr)
     if( pExpr->op!=TK_ID ){
       rc = sqlite3ResolveExprNames(pName, pExpr);
       if( rc==SQLITE_OK && !sqlite3ExprIsConstant(pExpr) ){
-        sqlite3ErrorMsg(pName->pParse, "invalid name: \"%T\"", &pExpr->span);
+        sqlite3ErrorMsg(pName->pParse, "invalid name: \"%s\"", pExpr->u.zToken);
         return SQLITE_ERROR;
       }
     }else{
@@ -60464,9 +79398,12 @@ static void attachFunc(
   sqlite3 *db = sqlite3_context_db_handle(context);
   const char *zName;
   const char *zFile;
+  char *zPath = 0;
+  char *zErr = 0;
+  unsigned int flags;
   Db *aNew;
   char *zErrDyn = 0;
-  char zErr[128];
+  sqlite3_vfs *pVfs;
 
   UNUSED_PARAMETER(NotUsed);
 
@@ -60482,22 +79419,20 @@ static void attachFunc(
   **     * Specified database name already being used.
   */
   if( db->nDb>=db->aLimit[SQLITE_LIMIT_ATTACHED]+2 ){
-    sqlite3_snprintf(
-      sizeof(zErr), zErr, "too many attached databases - max %d", 
+    zErrDyn = sqlite3MPrintf(db, "too many attached databases - max %d", 
       db->aLimit[SQLITE_LIMIT_ATTACHED]
     );
     goto attach_error;
   }
   if( !db->autoCommit ){
-    sqlite3_snprintf(sizeof(zErr), zErr,
-                     "cannot ATTACH database within transaction");
+    zErrDyn = sqlite3MPrintf(db, "cannot ATTACH database within transaction");
     goto attach_error;
   }
   for(i=0; i<db->nDb; i++){
     char *z = db->aDb[i].zName;
-    if( z && zName && sqlite3StrICmp(z, zName)==0 ){
-      sqlite3_snprintf(sizeof(zErr), zErr, 
-                       "database %s is already in use", zName);
+    assert( z && zName );
+    if( sqlite3StrICmp(z, zName)==0 ){
+      zErrDyn = sqlite3MPrintf(db, "database %s is already in use", zName);
       goto attach_error;
     }
   }
@@ -60514,35 +79449,53 @@ static void attachFunc(
     if( aNew==0 ) return;
   }
   db->aDb = aNew;
-  aNew = &db->aDb[db->nDb++];
+  aNew = &db->aDb[db->nDb];
   memset(aNew, 0, sizeof(*aNew));
 
   /* Open the database file. If the btree is successfully opened, use
   ** it to obtain the database schema. At this point the schema may
   ** or may not be initialised.
   */
-  rc = sqlite3BtreeFactory(db, zFile, 0, SQLITE_DEFAULT_CACHE_SIZE,
-                           db->openFlags | SQLITE_OPEN_MAIN_DB,
-                           &aNew->pBt);
-  if( rc==SQLITE_OK ){
+  flags = db->openFlags;
+  rc = sqlite3ParseUri(db->pVfs->zName, zFile, &flags, &pVfs, &zPath, &zErr);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
+    sqlite3_result_error(context, zErr, -1);
+    sqlite3_free(zErr);
+    return;
+  }
+  assert( pVfs );
+  flags |= SQLITE_OPEN_MAIN_DB;
+  rc = sqlite3BtreeOpen(pVfs, zPath, db, &aNew->pBt, 0, flags);
+  sqlite3_free( zPath );
+  db->nDb++;
+  if( rc==SQLITE_CONSTRAINT ){
+    rc = SQLITE_ERROR;
+    zErrDyn = sqlite3MPrintf(db, "database is already attached");
+  }else if( rc==SQLITE_OK ){
     Pager *pPager;
     aNew->pSchema = sqlite3SchemaGet(db, aNew->pBt);
     if( !aNew->pSchema ){
       rc = SQLITE_NOMEM;
     }else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){
-      sqlite3_snprintf(sizeof(zErr), zErr, 
+      zErrDyn = sqlite3MPrintf(db, 
         "attached databases must use the same text encoding as main database");
-      goto attach_error;
+      rc = SQLITE_ERROR;
     }
     pPager = sqlite3BtreePager(aNew->pBt);
     sqlite3PagerLockingMode(pPager, db->dfltLockMode);
-    sqlite3PagerJournalMode(pPager, db->dfltJournalMode);
+    sqlite3BtreeSecureDelete(aNew->pBt,
+                             sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) );
   }
-  aNew->zName = sqlite3DbStrDup(db, zName);
   aNew->safety_level = 3;
+  aNew->zName = sqlite3DbStrDup(db, zName);
+  if( rc==SQLITE_OK && aNew->zName==0 ){
+    rc = SQLITE_NOMEM;
+  }
 
-#if SQLITE_HAS_CODEC
-  {
+
+#ifdef SQLITE_HAS_CODEC
+  if( rc==SQLITE_OK ){
     extern int sqlite3CodecAttach(sqlite3*, int, const void*, int);
     extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*);
     int nKey;
@@ -60559,13 +79512,15 @@ static void attachFunc(
       case SQLITE_BLOB:
         nKey = sqlite3_value_bytes(argv[2]);
         zKey = (char *)sqlite3_value_blob(argv[2]);
-        sqlite3CodecAttach(db, db->nDb-1, zKey, nKey);
+        rc = sqlite3CodecAttach(db, db->nDb-1, zKey, nKey);
         break;
 
       case SQLITE_NULL:
         /* No key specified.  Use the key from the main database */
         sqlite3CodecGetKey(db, 0, (void**)&zKey, &nKey);
-        sqlite3CodecAttach(db, db->nDb-1, zKey, nKey);
+        if( nKey>0 || sqlite3BtreeGetReserve(db->aDb[0].pBt)>0 ){
+          rc = sqlite3CodecAttach(db, db->nDb-1, zKey, nKey);
+        }
         break;
     }
   }
@@ -60577,11 +79532,9 @@ static void attachFunc(
   ** we found it.
   */
   if( rc==SQLITE_OK ){
-    (void)sqlite3SafetyOn(db);
     sqlite3BtreeEnterAll(db);
     rc = sqlite3Init(db, &zErrDyn);
     sqlite3BtreeLeaveAll(db);
-    (void)sqlite3SafetyOff(db);
   }
   if( rc ){
     int iDb = db->nDb - 1;
@@ -60591,13 +79544,14 @@ static void attachFunc(
       db->aDb[iDb].pBt = 0;
       db->aDb[iDb].pSchema = 0;
     }
-    sqlite3ResetInternalSchema(db, 0);
+    sqlite3ResetAllSchemasOfConnection(db);
     db->nDb = iDb;
     if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
       db->mallocFailed = 1;
-      sqlite3_snprintf(sizeof(zErr),zErr, "out of memory");
-    }else{
-      sqlite3_snprintf(sizeof(zErr),zErr, "unable to open database: %s", zFile);
+      sqlite3DbFree(db, zErrDyn);
+      zErrDyn = sqlite3MPrintf(db, "out of memory");
+    }else if( zErrDyn==0 ){
+      zErrDyn = sqlite3MPrintf(db, "unable to open database: %s", zFile);
     }
     goto attach_error;
   }
@@ -60609,9 +79563,6 @@ attach_error:
   if( zErrDyn ){
     sqlite3_result_error(context, zErrDyn, -1);
     sqlite3DbFree(db, zErrDyn);
-  }else{
-    zErr[sizeof(zErr)-1] = 0;
-    sqlite3_result_error(context, zErr, -1);
   }
   if( rc ) sqlite3_result_error_code(context, rc);
 }
@@ -60657,7 +79608,7 @@ static void detachFunc(
                      "cannot DETACH database within transaction");
     goto detach_error;
   }
-  if( sqlite3BtreeIsInReadTrans(pDb->pBt) ){
+  if( sqlite3BtreeIsInReadTrans(pDb->pBt) || sqlite3BtreeIsInBackup(pDb->pBt) ){
     sqlite3_snprintf(sizeof(zErr),zErr, "database %s is locked", zName);
     goto detach_error;
   }
@@ -60665,7 +79616,7 @@ static void detachFunc(
   sqlite3BtreeClose(pDb->pBt);
   pDb->pBt = 0;
   pDb->pSchema = 0;
-  sqlite3ResetInternalSchema(db, 0);
+  sqlite3ResetAllSchemasOfConnection(db);
   return;
 
 detach_error:
@@ -60679,7 +79630,7 @@ detach_error:
 static void codeAttach(
   Parse *pParse,       /* The parser context */
   int type,            /* Either SQLITE_ATTACH or SQLITE_DETACH */
-  FuncDef *pFunc,      /* FuncDef wrapper for detachFunc() or attachFunc() */
+  FuncDef const *pFunc,/* FuncDef wrapper for detachFunc() or attachFunc() */
   Expr *pAuthArg,      /* Expression to pass to authorization callback */
   Expr *pFilename,     /* Name of database file */
   Expr *pDbname,       /* Name of the database to use internally */
@@ -60691,21 +79642,6 @@ static void codeAttach(
   sqlite3* db = pParse->db;
   int regArgs;
 
-#ifndef SQLITE_OMIT_AUTHORIZATION
-  assert( db->mallocFailed || pAuthArg );
-  if( pAuthArg ){
-    char *zAuthArg = sqlite3NameFromToken(db, &pAuthArg->span);
-    if( !zAuthArg ){
-      goto attach_end;
-    }
-    rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
-    sqlite3DbFree(db, zAuthArg);
-    if(rc!=SQLITE_OK ){
-      goto attach_end;
-    }
-  }
-#endif /* SQLITE_OMIT_AUTHORIZATION */
-
   memset(&sName, 0, sizeof(NameContext));
   sName.pParse = pParse;
 
@@ -60718,6 +79654,22 @@ static void codeAttach(
     goto attach_end;
   }
 
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( pAuthArg ){
+    char *zAuthArg;
+    if( pAuthArg->op==TK_STRING ){
+      zAuthArg = pAuthArg->u.zToken;
+    }else{
+      zAuthArg = 0;
+    }
+    rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
+    if(rc!=SQLITE_OK ){
+      goto attach_end;
+    }
+  }
+#endif /* SQLITE_OMIT_AUTHORIZATION */
+
+
   v = sqlite3GetVdbe(pParse);
   regArgs = sqlite3GetTempRange(pParse, 4);
   sqlite3ExprCode(pParse, pFilename, regArgs);
@@ -60750,7 +79702,7 @@ attach_end:
 **     DETACH pDbname
 */
 SQLITE_PRIVATE void sqlite3Detach(Parse *pParse, Expr *pDbname){
-  static FuncDef detach_func = {
+  static const FuncDef detach_func = {
     1,                /* nArg */
     SQLITE_UTF8,      /* iPrefEnc */
     0,                /* flags */
@@ -60760,7 +79712,8 @@ SQLITE_PRIVATE void sqlite3Detach(Parse *pParse, Expr *pDbname){
     0,                /* xStep */
     0,                /* xFinalize */
     "sqlite_detach",  /* zName */
-    0                 /* pHash */
+    0,                /* pHash */
+    0                 /* pDestructor */
   };
   codeAttach(pParse, SQLITE_DETACH, &detach_func, pDbname, 0, 0, pDbname);
 }
@@ -60771,7 +79724,7 @@ SQLITE_PRIVATE void sqlite3Detach(Parse *pParse, Expr *pDbname){
 **     ATTACH p AS pDbname KEY pKey
 */
 SQLITE_PRIVATE void sqlite3Attach(Parse *pParse, Expr *p, Expr *pDbname, Expr *pKey){
-  static FuncDef attach_func = {
+  static const FuncDef attach_func = {
     3,                /* nArg */
     SQLITE_UTF8,      /* iPrefEnc */
     0,                /* flags */
@@ -60781,7 +79734,8 @@ SQLITE_PRIVATE void sqlite3Attach(Parse *pParse, Expr *p, Expr *pDbname, Expr *p
     0,                /* xStep */
     0,                /* xFinalize */
     "sqlite_attach",  /* zName */
-    0                 /* pHash */
+    0,                /* pHash */
+    0                 /* pDestructor */
   };
   codeAttach(pParse, SQLITE_ATTACH, &attach_func, p, p, pDbname, pKey);
 }
@@ -60803,7 +79757,7 @@ SQLITE_PRIVATE int sqlite3FixInit(
 ){
   sqlite3 *db;
 
-  if( iDb<0 || iDb==1 ) return 0;
+  if( NEVER(iDb<0) || iDb==1 ) return 0;
   db = pParse->db;
   assert( db->nDb>iDb );
   pFix->pParse = pParse;
@@ -60835,7 +79789,7 @@ SQLITE_PRIVATE int sqlite3FixSrcList(
   const char *zDb;
   struct SrcList_item *pItem;
 
-  if( pList==0 ) return 0;
+  if( NEVER(pList==0) ) return 0;
   zDb = pFix->zDb;
   for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
     if( pItem->zDatabase==0 ){
@@ -60880,11 +79834,11 @@ SQLITE_PRIVATE int sqlite3FixExpr(
   Expr *pExpr        /* The expression to be fixed to one database */
 ){
   while( pExpr ){
-    if( sqlite3FixSelect(pFix, pExpr->pSelect) ){
-      return 1;
-    }
-    if( sqlite3FixExprList(pFix, pExpr->pList) ){
-      return 1;
+    if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ) break;
+    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+      if( sqlite3FixSelect(pFix, pExpr->x.pSelect) ) return 1;
+    }else{
+      if( sqlite3FixExprList(pFix, pExpr->x.pList) ) return 1;
     }
     if( sqlite3FixExpr(pFix, pExpr->pRight) ){
       return 1;
@@ -60947,8 +79901,6 @@ SQLITE_PRIVATE int sqlite3FixTriggerStep(
 ** API.  This facility is an optional feature of the library.  Embedded
 ** systems that do not need this facility may omit it by recompiling
 ** the library with -DSQLITE_OMIT_AUTHORIZATION=1
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -61019,13 +79971,44 @@ SQLITE_API int sqlite3_set_authorizer(
 ** Write an error message into pParse->zErrMsg that explains that the
 ** user-supplied authorization function returned an illegal value.
 */
-static void sqliteAuthBadReturnCode(Parse *pParse, int rc){
-  sqlite3ErrorMsg(pParse, "illegal return value (%d) from the "
-    "authorization function - should be SQLITE_OK, SQLITE_IGNORE, "
-    "or SQLITE_DENY", rc);
+static void sqliteAuthBadReturnCode(Parse *pParse){
+  sqlite3ErrorMsg(pParse, "authorizer malfunction");
   pParse->rc = SQLITE_ERROR;
 }
 
+/*
+** Invoke the authorization callback for permission to read column zCol from
+** table zTab in database zDb. This function assumes that an authorization
+** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
+**
+** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
+** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
+** is treated as SQLITE_DENY. In this case an error is left in pParse.
+*/
+SQLITE_PRIVATE int sqlite3AuthReadCol(
+  Parse *pParse,                  /* The parser context */
+  const char *zTab,               /* Table name */
+  const char *zCol,               /* Column name */
+  int iDb                         /* Index of containing database. */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  char *zDb = db->aDb[iDb].zName; /* Name of attached database */
+  int rc;                         /* Auth callback return code */
+
+  rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext);
+  if( rc==SQLITE_DENY ){
+    if( db->nDb>2 || iDb!=0 ){
+      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited",zDb,zTab,zCol);
+    }else{
+      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited", zTab, zCol);
+    }
+    pParse->rc = SQLITE_AUTH;
+  }else if( rc!=SQLITE_IGNORE && rc!=SQLITE_OK ){
+    sqliteAuthBadReturnCode(pParse);
+  }
+  return rc;
+}
+
 /*
 ** The pExpr should be a TK_COLUMN expression.  The table referred to
 ** is in pTabList or else it is the NEW or OLD table of a trigger.  
@@ -61042,38 +80025,38 @@ SQLITE_PRIVATE void sqlite3AuthRead(
   SrcList *pTabList     /* All table that pExpr might refer to */
 ){
   sqlite3 *db = pParse->db;
-  int rc;
   Table *pTab = 0;      /* The table being read */
   const char *zCol;     /* Name of the column of the table */
   int iSrc;             /* Index in pTabList->a[] of table being read */
-  const char *zDBase;   /* Name of database being accessed */
-  TriggerStack *pStack; /* The stack of current triggers */
   int iDb;              /* The index of the database the expression refers to */
+  int iCol;             /* Index of column in table */
 
   if( db->xAuth==0 ) return;
-  if( pExpr->op!=TK_COLUMN ) return;
   iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
   if( iDb<0 ){
     /* An attempt to read a column out of a subquery or other
     ** temporary table. */
     return;
   }
-  for(iSrc=0; pTabList && iSrc<pTabList->nSrc; iSrc++){
-    if( pExpr->iTable==pTabList->a[iSrc].iCursor ) break;
+
+  assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
+  if( pExpr->op==TK_TRIGGER ){
+    pTab = pParse->pTriggerTab;
+  }else{
+    assert( pTabList );
+    for(iSrc=0; ALWAYS(iSrc<pTabList->nSrc); iSrc++){
+      if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
+        pTab = pTabList->a[iSrc].pTab;
+        break;
+      }
+    }
   }
-  if( iSrc>=0 && pTabList && iSrc<pTabList->nSrc ){
-    pTab = pTabList->a[iSrc].pTab;
-  }else if( (pStack = pParse->trigStack)!=0 ){
-    /* This must be an attempt to read the NEW or OLD pseudo-tables
-    ** of a trigger.
-    */
-    assert( pExpr->iTable==pStack->newIdx || pExpr->iTable==pStack->oldIdx );
-    pTab = pStack->pTab;
-  }
-  if( pTab==0 ) return;
-  if( pExpr->iColumn>=0 ){
-    assert( pExpr->iColumn<pTab->nCol );
-    zCol = pTab->aCol[pExpr->iColumn].zName;
+  iCol = pExpr->iColumn;
+  if( NEVER(pTab==0) ) return;
+
+  if( iCol>=0 ){
+    assert( iCol<pTab->nCol );
+    zCol = pTab->aCol[iCol].zName;
   }else if( pTab->iPKey>=0 ){
     assert( pTab->iPKey<pTab->nCol );
     zCol = pTab->aCol[pTab->iPKey].zName;
@@ -61081,21 +80064,8 @@ SQLITE_PRIVATE void sqlite3AuthRead(
     zCol = "ROWID";
   }
   assert( iDb>=0 && iDb<db->nDb );
-  zDBase = db->aDb[iDb].zName;
-  rc = db->xAuth(db->pAuthArg, SQLITE_READ, pTab->zName, zCol, zDBase, 
-                 pParse->zAuthContext);
-  if( rc==SQLITE_IGNORE ){
+  if( SQLITE_IGNORE==sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb) ){
     pExpr->op = TK_NULL;
-  }else if( rc==SQLITE_DENY ){
-    if( db->nDb>2 || iDb!=0 ){
-      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited", 
-         zDBase, pTab->zName, zCol);
-    }else{
-      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited",pTab->zName,zCol);
-    }
-    pParse->rc = SQLITE_AUTH;
-  }else if( rc!=SQLITE_OK ){
-    sqliteAuthBadReturnCode(pParse, rc);
   }
 }
 
@@ -61131,7 +80101,7 @@ SQLITE_PRIVATE int sqlite3AuthCheck(
     pParse->rc = SQLITE_AUTH;
   }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
     rc = SQLITE_DENY;
-    sqliteAuthBadReturnCode(pParse, rc);
+    sqliteAuthBadReturnCode(pParse);
   }
   return rc;
 }
@@ -61146,11 +80116,10 @@ SQLITE_PRIVATE void sqlite3AuthContextPush(
   AuthContext *pContext, 
   const char *zContext
 ){
+  assert( pParse );
   pContext->pParse = pParse;
-  if( pParse ){
-    pContext->zAuthContext = pParse->zAuthContext;
-    pParse->zAuthContext = zContext;
-  }
+  pContext->zAuthContext = pParse->zAuthContext;
+  pParse->zAuthContext = zContext;
 }
 
 /*
@@ -61191,8 +80160,6 @@ SQLITE_PRIVATE void sqlite3AuthContextPop(AuthContext *pContext){
 **     BEGIN TRANSACTION
 **     COMMIT
 **     ROLLBACK
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -61233,34 +80200,32 @@ SQLITE_PRIVATE void sqlite3TableLock(
   u8 isWriteLock,    /* True for a write lock */
   const char *zName  /* Name of the table to be locked */
 ){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
   int i;
   int nBytes;
   TableLock *p;
+  assert( iDb>=0 );
 
-  if( iDb<0 ){
-    return;
-  }
-
-  for(i=0; i<pParse->nTableLock; i++){
-    p = &pParse->aTableLock[i];
+  for(i=0; i<pToplevel->nTableLock; i++){
+    p = &pToplevel->aTableLock[i];
     if( p->iDb==iDb && p->iTab==iTab ){
       p->isWriteLock = (p->isWriteLock || isWriteLock);
       return;
     }
   }
 
-  nBytes = sizeof(TableLock) * (pParse->nTableLock+1);
-  pParse->aTableLock = 
-      sqlite3DbReallocOrFree(pParse->db, pParse->aTableLock, nBytes);
-  if( pParse->aTableLock ){
-    p = &pParse->aTableLock[pParse->nTableLock++];
+  nBytes = sizeof(TableLock) * (pToplevel->nTableLock+1);
+  pToplevel->aTableLock =
+      sqlite3DbReallocOrFree(pToplevel->db, pToplevel->aTableLock, nBytes);
+  if( pToplevel->aTableLock ){
+    p = &pToplevel->aTableLock[pToplevel->nTableLock++];
     p->iDb = iDb;
     p->iTab = iTab;
     p->isWriteLock = isWriteLock;
     p->zName = zName;
   }else{
-    pParse->nTableLock = 0;
-    pParse->db->mallocFailed = 1;
+    pToplevel->nTableLock = 0;
+    pToplevel->db->mallocFailed = 1;
   }
 }
 
@@ -61272,9 +80237,8 @@ static void codeTableLocks(Parse *pParse){
   int i;
   Vdbe *pVdbe; 
 
-  if( 0==(pVdbe = sqlite3GetVdbe(pParse)) ){
-    return;
-  }
+  pVdbe = sqlite3GetVdbe(pParse);
+  assert( pVdbe!=0 ); /* sqlite3GetVdbe cannot fail: VDBE already allocated */
 
   for(i=0; i<pParse->nTableLock; i++){
     TableLock *p = &pParse->aTableLock[i];
@@ -61310,6 +80274,8 @@ SQLITE_PRIVATE void sqlite3FinishCoding(Parse *pParse){
   ** vdbe program
   */
   v = sqlite3GetVdbe(pParse);
+  assert( !pParse->isMultiWrite 
+       || sqlite3VdbeAssertMayAbort(v, pParse->mayAbort));
   if( v ){
     sqlite3VdbeAddOp0(v, OP_Halt);
 
@@ -61320,20 +80286,25 @@ SQLITE_PRIVATE void sqlite3FinishCoding(Parse *pParse){
     ** on each used database.
     */
     if( pParse->cookieGoto>0 ){
-      u32 mask;
+      yDbMask mask;
       int iDb;
       sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
       for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
         if( (mask & pParse->cookieMask)==0 ) continue;
         sqlite3VdbeUsesBtree(v, iDb);
         sqlite3VdbeAddOp2(v,OP_Transaction, iDb, (mask & pParse->writeMask)!=0);
-        sqlite3VdbeAddOp2(v,OP_VerifyCookie, iDb, pParse->cookieValue[iDb]);
+        if( db->init.busy==0 ){
+          assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+          sqlite3VdbeAddOp3(v, OP_VerifyCookie,
+                            iDb, pParse->cookieValue[iDb],
+                            db->aDb[iDb].pSchema->iGeneration);
+        }
       }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
       {
         int i;
         for(i=0; i<pParse->nVtabLock; i++){
-          char *vtab = (char *)pParse->apVtabLock[i]->pVtab;
+          char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
           sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
         }
         pParse->nVtabLock = 0;
@@ -61345,37 +80316,32 @@ SQLITE_PRIVATE void sqlite3FinishCoding(Parse *pParse){
       ** shared-cache feature is enabled.
       */
       codeTableLocks(pParse);
+
+      /* Initialize any AUTOINCREMENT data structures required.
+      */
+      sqlite3AutoincrementBegin(pParse);
+
+      /* Finally, jump back to the beginning of the executable code. */
       sqlite3VdbeAddOp2(v, OP_Goto, 0, pParse->cookieGoto);
     }
-
-#ifndef SQLITE_OMIT_TRACE
-    if( !db->init.busy ){
-      /* Change the P4 argument of the first opcode (which will always be
-      ** an OP_Trace) to be the complete text of the current SQL statement.
-      */
-      VdbeOp *pOp = sqlite3VdbeGetOp(v, 0);
-      if( pOp && pOp->opcode==OP_Trace ){
-        sqlite3VdbeChangeP4(v, 0, pParse->zSql,
-                            (int)(pParse->zTail - pParse->zSql));
-      }
-    }
-#endif /* SQLITE_OMIT_TRACE */
   }
 
 
   /* Get the VDBE program ready for execution
   */
-  if( v && pParse->nErr==0 && !db->mallocFailed ){
+  if( v && ALWAYS(pParse->nErr==0) && !db->mallocFailed ){
 #ifdef SQLITE_DEBUG
     FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
     sqlite3VdbeTrace(v, trace);
 #endif
-    assert( pParse->disableColCache==0 );  /* Disables and re-enables match */
-    sqlite3VdbeMakeReady(v, pParse->nVar, pParse->nMem+3,
-                         pParse->nTab+3, pParse->explain);
+    assert( pParse->iCacheLevel==0 );  /* Disables and re-enables match */
+    /* A minimum of one cursor is required if autoincrement is used
+    *  See ticket [a696379c1f08866] */
+    if( pParse->pAinc!=0 && pParse->nTab==0 ) pParse->nTab = 1;
+    sqlite3VdbeMakeReady(v, pParse);
     pParse->rc = SQLITE_DONE;
     pParse->colNamesSet = 0;
-  }else if( pParse->rc==SQLITE_OK ){
+  }else{
     pParse->rc = SQLITE_ERROR;
   }
   pParse->nTab = 0;
@@ -61441,10 +80407,13 @@ SQLITE_PRIVATE Table *sqlite3FindTable(sqlite3 *db, const char *zName, const cha
   int i;
   int nName;
   assert( zName!=0 );
-  nName = sqlite3Strlen(db, zName) + 1;
+  nName = sqlite3Strlen30(zName);
+  /* All mutexes are required for schema access.  Make sure we hold them. */
+  assert( zDatabase!=0 || sqlite3BtreeHoldsAllMutexes(db) );
   for(i=OMIT_TEMPDB; i<db->nDb; i++){
     int j = (i<2) ? i^1 : i;   /* Search TEMP before MAIN */
     if( zDatabase!=0 && sqlite3StrICmp(zDatabase, db->aDb[j].zName) ) continue;
+    assert( sqlite3SchemaMutexHeld(db, j, 0) );
     p = sqlite3HashFind(&db->aDb[j].pSchema->tblHash, zName, nName);
     if( p ) break;
   }
@@ -61503,15 +80472,16 @@ SQLITE_PRIVATE Table *sqlite3LocateTable(
 SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const char *zDb){
   Index *p = 0;
   int i;
-  int nName = sqlite3Strlen(db, zName)+1;
+  int nName = sqlite3Strlen30(zName);
+  /* All mutexes are required for schema access.  Make sure we hold them. */
+  assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
   for(i=OMIT_TEMPDB; i<db->nDb; i++){
     int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
     Schema *pSchema = db->aDb[j].pSchema;
+    assert( pSchema );
     if( zDb && sqlite3StrICmp(zDb, db->aDb[j].zName) ) continue;
-    assert( pSchema || (j==1 && !db->aDb[1].pBt) );
-    if( pSchema ){
-      p = sqlite3HashFind(&pSchema->idxHash, zName, nName);
-    }
+    assert( sqlite3SchemaMutexHeld(db, j, 0) );
+    p = sqlite3HashFind(&pSchema->idxHash, zName, nName);
     if( p ) break;
   }
   return p;
@@ -61520,30 +80490,14 @@ SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const cha
 /*
 ** Reclaim the memory used by an index
 */
-static void freeIndex(Index *p){
-  sqlite3 *db = p->pTable->db;
+static void freeIndex(sqlite3 *db, Index *p){
+#ifndef SQLITE_OMIT_ANALYZE
+  sqlite3DeleteIndexSamples(db, p);
+#endif
   sqlite3DbFree(db, p->zColAff);
   sqlite3DbFree(db, p);
 }
 
-/*
-** Remove the given index from the index hash table, and free
-** its memory structures.
-**
-** The index is removed from the database hash tables but
-** it is not unlinked from the Table that it indexes.
-** Unlinking from the Table must be done by the calling function.
-*/
-static void sqliteDeleteIndex(Index *p){
-  Index *pOld;
-  const char *zName = p->zName;
-
-  pOld = sqlite3HashInsert(&p->pSchema->idxHash, zName,
-                           sqlite3Strlen30(zName)+1, 0);
-  assert( pOld==0 || pOld==p );
-  freeIndex(p);
-}
-
 /*
 ** For the index called zIdxName which is found in the database iDb,
 ** unlike that index from its Table then remove the index from
@@ -61553,68 +80507,40 @@ static void sqliteDeleteIndex(Index *p){
 SQLITE_PRIVATE void sqlite3UnlinkAndDeleteIndex(sqlite3 *db, int iDb, const char *zIdxName){
   Index *pIndex;
   int len;
-  Hash *pHash = &db->aDb[iDb].pSchema->idxHash;
+  Hash *pHash;
 
-  len = sqlite3Strlen(db, zIdxName);
-  pIndex = sqlite3HashInsert(pHash, zIdxName, len+1, 0);
-  if( pIndex ){
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pHash = &db->aDb[iDb].pSchema->idxHash;
+  len = sqlite3Strlen30(zIdxName);
+  pIndex = sqlite3HashInsert(pHash, zIdxName, len, 0);
+  if( ALWAYS(pIndex) ){
     if( pIndex->pTable->pIndex==pIndex ){
       pIndex->pTable->pIndex = pIndex->pNext;
     }else{
       Index *p;
-      for(p=pIndex->pTable->pIndex; p && p->pNext!=pIndex; p=p->pNext){}
-      if( p && p->pNext==pIndex ){
+      /* Justification of ALWAYS();  The index must be on the list of
+      ** indices. */
+      p = pIndex->pTable->pIndex;
+      while( ALWAYS(p) && p->pNext!=pIndex ){ p = p->pNext; }
+      if( ALWAYS(p && p->pNext==pIndex) ){
         p->pNext = pIndex->pNext;
       }
     }
-    freeIndex(pIndex);
+    freeIndex(db, pIndex);
   }
   db->flags |= SQLITE_InternChanges;
 }
 
 /*
-** Erase all schema information from the in-memory hash tables of
-** a single database.  This routine is called to reclaim memory
-** before the database closes.  It is also called during a rollback
-** if there were schema changes during the transaction or if a
-** schema-cookie mismatch occurs.
+** Look through the list of open database files in db->aDb[] and if
+** any have been closed, remove them from the list.  Reallocate the
+** db->aDb[] structure to a smaller size, if possible.
 **
-** If iDb<=0 then reset the internal schema tables for all database
-** files.  If iDb>=2 then reset the internal schema for only the
-** single file indicated.
+** Entry 0 (the "main" database) and entry 1 (the "temp" database)
+** are never candidates for being collapsed.
 */
-SQLITE_PRIVATE void sqlite3ResetInternalSchema(sqlite3 *db, int iDb){
+SQLITE_PRIVATE void sqlite3CollapseDatabaseArray(sqlite3 *db){
   int i, j;
-  assert( iDb>=0 && iDb<db->nDb );
-
-  if( iDb==0 ){
-    sqlite3BtreeEnterAll(db);
-  }
-  for(i=iDb; i<db->nDb; i++){
-    Db *pDb = &db->aDb[i];
-    if( pDb->pSchema ){
-      assert(i==1 || (pDb->pBt && sqlite3BtreeHoldsMutex(pDb->pBt)));
-      sqlite3SchemaFree(pDb->pSchema);
-    }
-    if( iDb>0 ) return;
-  }
-  assert( iDb==0 );
-  db->flags &= ~SQLITE_InternChanges;
-  sqlite3BtreeLeaveAll(db);
-
-  /* If one or more of the auxiliary database files has been closed,
-  ** then remove them from the auxiliary database list.  We take the
-  ** opportunity to do this here since we have just deleted all of the
-  ** schema hash tables and therefore do not have to make any changes
-  ** to any of those tables.
-  */
-  for(i=0; i<db->nDb; i++){
-    struct Db *pDb = &db->aDb[i];
-    if( pDb->pBt==0 ){
-      if( pDb->pAux && pDb->xFreeAux ) pDb->xFreeAux(pDb->pAux);
-      pDb->pAux = 0;
-    }
-  }
   for(i=j=2; i<db->nDb; i++){
     struct Db *pDb = &db->aDb[i];
     if( pDb->pBt==0 ){
@@ -61636,6 +80562,51 @@ SQLITE_PRIVATE void sqlite3ResetInternalSchema(sqlite3 *db, int iDb){
   }
 }
 
+/*
+** Reset the schema for the database at index iDb.  Also reset the
+** TEMP schema.
+*/
+SQLITE_PRIVATE void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
+  Db *pDb;
+  assert( iDb<db->nDb );
+
+  /* Case 1:  Reset the single schema identified by iDb */
+  pDb = &db->aDb[iDb];
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  assert( pDb->pSchema!=0 );
+  sqlite3SchemaClear(pDb->pSchema);
+
+  /* If any database other than TEMP is reset, then also reset TEMP
+  ** since TEMP might be holding triggers that reference tables in the
+  ** other database.
+  */
+  if( iDb!=1 ){
+    pDb = &db->aDb[1];
+    assert( pDb->pSchema!=0 );
+    sqlite3SchemaClear(pDb->pSchema);
+  }
+  return;
+}
+
+/*
+** Erase all schema information from all attached databases (including
+** "main" and "temp") for a single database connection.
+*/
+SQLITE_PRIVATE void sqlite3ResetAllSchemasOfConnection(sqlite3 *db){
+  int i;
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Db *pDb = &db->aDb[i];
+    if( pDb->pSchema ){
+      sqlite3SchemaClear(pDb->pSchema);
+    }
+  }
+  db->flags &= ~SQLITE_InternChanges;
+  sqlite3VtabUnlockList(db);
+  sqlite3BtreeLeaveAll(db);
+  sqlite3CollapseDatabaseArray(db);
+}
+
 /*
 ** This routine is called when a commit occurs.
 */
@@ -61644,24 +80615,23 @@ SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3 *db){
 }
 
 /*
-** Clear the column names from a table or view.
+** Delete memory allocated for the column names of a table or view (the
+** Table.aCol[] array).
 */
-static void sqliteResetColumnNames(Table *pTable){
+static void sqliteDeleteColumnNames(sqlite3 *db, Table *pTable){
   int i;
   Column *pCol;
-  sqlite3 *db = pTable->db;
   assert( pTable!=0 );
   if( (pCol = pTable->aCol)!=0 ){
     for(i=0; i<pTable->nCol; i++, pCol++){
       sqlite3DbFree(db, pCol->zName);
       sqlite3ExprDelete(db, pCol->pDflt);
+      sqlite3DbFree(db, pCol->zDflt);
       sqlite3DbFree(db, pCol->zType);
       sqlite3DbFree(db, pCol->zColl);
     }
     sqlite3DbFree(db, pTable->aCol);
   }
-  pTable->aCol = 0;
-  pTable->nCol = 0;
 }
 
 /*
@@ -61669,57 +80639,66 @@ static void sqliteResetColumnNames(Table *pTable){
 ** Table.  No changes are made to disk by this routine.
 **
 ** This routine just deletes the data structure.  It does not unlink
-** the table data structure from the hash table.  Nor does it remove
-** foreign keys from the sqlite.aFKey hash table.  But it does destroy
+** the table data structure from the hash table.  But it does destroy
 ** memory structures of the indices and foreign keys associated with 
 ** the table.
+**
+** The db parameter is optional.  It is needed if the Table object 
+** contains lookaside memory.  (Table objects in the schema do not use
+** lookaside memory, but some ephemeral Table objects do.)  Or the
+** db parameter can be used with db->pnBytesFreed to measure the memory
+** used by the Table object.
 */
-SQLITE_PRIVATE void sqlite3DeleteTable(Table *pTable){
+SQLITE_PRIVATE void sqlite3DeleteTable(sqlite3 *db, Table *pTable){
   Index *pIndex, *pNext;
-  FKey *pFKey, *pNextFKey;
-  sqlite3 *db;
+  TESTONLY( int nLookaside; ) /* Used to verify lookaside not used for schema */
 
-  if( pTable==0 ) return;
-  db = pTable->db;
+  assert( !pTable || pTable->nRef>0 );
 
   /* Do not delete the table until the reference count reaches zero. */
-  pTable->nRef--;
-  if( pTable->nRef>0 ){
-    return;
-  }
-  assert( pTable->nRef==0 );
+  if( !pTable ) return;
+  if( ((!db || db->pnBytesFreed==0) && (--pTable->nRef)>0) ) return;
 
-  /* Delete all indices associated with this table
-  */
+  /* Record the number of outstanding lookaside allocations in schema Tables
+  ** prior to doing any free() operations.  Since schema Tables do not use
+  ** lookaside, this number should not change. */
+  TESTONLY( nLookaside = (db && (pTable->tabFlags & TF_Ephemeral)==0) ?
+                         db->lookaside.nOut : 0 );
+
+  /* Delete all indices associated with this table. */
   for(pIndex = pTable->pIndex; pIndex; pIndex=pNext){
     pNext = pIndex->pNext;
     assert( pIndex->pSchema==pTable->pSchema );
-    sqliteDeleteIndex(pIndex);
+    if( !db || db->pnBytesFreed==0 ){
+      char *zName = pIndex->zName; 
+      TESTONLY ( Index *pOld = ) sqlite3HashInsert(
+         &pIndex->pSchema->idxHash, zName, sqlite3Strlen30(zName), 0
+      );
+      assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pIndex->pSchema) );
+      assert( pOld==pIndex || pOld==0 );
+    }
+    freeIndex(db, pIndex);
   }
 
-#ifndef SQLITE_OMIT_FOREIGN_KEY
-  /* Delete all foreign keys associated with this table.  The keys
-  ** should have already been unlinked from the pSchema->aFKey hash table 
-  */
-  for(pFKey=pTable->pFKey; pFKey; pFKey=pNextFKey){
-    pNextFKey = pFKey->pNextFrom;
-    assert( sqlite3HashFind(&pTable->pSchema->aFKey,
-                           pFKey->zTo, sqlite3Strlen30(pFKey->zTo)+1)!=pFKey );
-    sqlite3DbFree(db, pFKey);
-  }
-#endif
+  /* Delete any foreign keys attached to this table. */
+  sqlite3FkDelete(db, pTable);
 
   /* Delete the Table structure itself.
   */
-  sqliteResetColumnNames(pTable);
+  sqliteDeleteColumnNames(db, pTable);
   sqlite3DbFree(db, pTable->zName);
   sqlite3DbFree(db, pTable->zColAff);
   sqlite3SelectDelete(db, pTable->pSelect);
 #ifndef SQLITE_OMIT_CHECK
-  sqlite3ExprDelete(db, pTable->pCheck);
+  sqlite3ExprListDelete(db, pTable->pCheck);
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3VtabClear(db, pTable);
 #endif
-  sqlite3VtabClear(pTable);
   sqlite3DbFree(db, pTable);
+
+  /* Verify that no lookaside memory was used by schema tables */
+  assert( nLookaside==0 || nLookaside==db->lookaside.nOut );
 }
 
 /*
@@ -61728,41 +80707,29 @@ SQLITE_PRIVATE void sqlite3DeleteTable(Table *pTable){
 */
 SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3 *db, int iDb, const char *zTabName){
   Table *p;
-  FKey *pF1, *pF2;
   Db *pDb;
 
   assert( db!=0 );
   assert( iDb>=0 && iDb<db->nDb );
-  assert( zTabName && zTabName[0] );
+  assert( zTabName );
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  testcase( zTabName[0]==0 );  /* Zero-length table names are allowed */
   pDb = &db->aDb[iDb];
   p = sqlite3HashInsert(&pDb->pSchema->tblHash, zTabName,
-                        sqlite3Strlen30(zTabName)+1,0);
-  if( p ){
-#ifndef SQLITE_OMIT_FOREIGN_KEY
-    for(pF1=p->pFKey; pF1; pF1=pF1->pNextFrom){
-      int nTo = sqlite3Strlen30(pF1->zTo) + 1;
-      pF2 = sqlite3HashFind(&pDb->pSchema->aFKey, pF1->zTo, nTo);
-      if( pF2==pF1 ){
-        sqlite3HashInsert(&pDb->pSchema->aFKey, pF1->zTo, nTo, pF1->pNextTo);
-      }else{
-        while( pF2 && pF2->pNextTo!=pF1 ){ pF2=pF2->pNextTo; }
-        if( pF2 ){
-          pF2->pNextTo = pF1->pNextTo;
-        }
-      }
-    }
-#endif
-    sqlite3DeleteTable(p);
-  }
+                        sqlite3Strlen30(zTabName),0);
+  sqlite3DeleteTable(db, p);
   db->flags |= SQLITE_InternChanges;
 }
 
 /*
 ** Given a token, return a string that consists of the text of that
-** token with any quotations removed.  Space to hold the returned string
+** token.  Space to hold the returned string
 ** is obtained from sqliteMalloc() and must be freed by the calling
 ** function.
 **
+** Any quotation marks (ex:  "name", 'name', [name], or `name`) that
+** surround the body of the token are removed.
+**
 ** Tokens are often just pointers into the original SQL text and so
 ** are not \000 terminated and are not persistent.  The returned string
 ** is \000 terminated and is persistent.
@@ -61785,8 +80752,32 @@ SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3 *db, Token *pName){
 SQLITE_PRIVATE void sqlite3OpenMasterTable(Parse *p, int iDb){
   Vdbe *v = sqlite3GetVdbe(p);
   sqlite3TableLock(p, iDb, MASTER_ROOT, 1, SCHEMA_TABLE(iDb));
-  sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, 5);/* sqlite_master has 5 columns */
   sqlite3VdbeAddOp3(v, OP_OpenWrite, 0, MASTER_ROOT, iDb);
+  sqlite3VdbeChangeP4(v, -1, (char *)5, P4_INT32);  /* 5 column table */
+  if( p->nTab==0 ){
+    p->nTab = 1;
+  }
+}
+
+/*
+** Parameter zName points to a nul-terminated buffer containing the name
+** of a database ("main", "temp" or the name of an attached db). This
+** function returns the index of the named database in db->aDb[], or
+** -1 if the named db cannot be found.
+*/
+SQLITE_PRIVATE int sqlite3FindDbName(sqlite3 *db, const char *zName){
+  int i = -1;         /* Database number */
+  if( zName ){
+    Db *pDb;
+    int n = sqlite3Strlen30(zName);
+    for(i=(db->nDb-1), pDb=&db->aDb[i]; i>=0; i--, pDb--){
+      if( (!OMIT_TEMPDB || i!=1 ) && n==sqlite3Strlen30(pDb->zName) && 
+          0==sqlite3StrICmp(pDb->zName, zName) ){
+        break;
+      }
+    }
+  }
+  return i;
 }
 
 /*
@@ -61796,22 +80787,11 @@ SQLITE_PRIVATE void sqlite3OpenMasterTable(Parse *p, int iDb){
 ** does not exist.
 */
 SQLITE_PRIVATE int sqlite3FindDb(sqlite3 *db, Token *pName){
-  int i = -1;    /* Database number */
-  int n;         /* Number of characters in the name */
-  Db *pDb;       /* A database whose name space is being searched */
-  char *zName;   /* Name we are searching for */
-
+  int i;                               /* Database number */
+  char *zName;                         /* Name we are searching for */
   zName = sqlite3NameFromToken(db, pName);
-  if( zName ){
-    n = sqlite3Strlen30(zName);
-    for(i=(db->nDb-1), pDb=&db->aDb[i]; i>=0; i--, pDb--){
-      if( (!OMIT_TEMPDB || i!=1 ) && n==sqlite3Strlen30(pDb->zName) && 
-          0==sqlite3StrICmp(pDb->zName, zName) ){
-        break;
-      }
-    }
-    sqlite3DbFree(db, zName);
-  }
+  i = sqlite3FindDbName(db, zName);
+  sqlite3DbFree(db, zName);
   return i;
 }
 
@@ -61840,7 +80820,7 @@ SQLITE_PRIVATE int sqlite3TwoPartName(
   int iDb;                    /* Database holding the object */
   sqlite3 *db = pParse->db;
 
-  if( pName2 && pName2->n>0 ){
+  if( ALWAYS(pName2!=0) && pName2->n>0 ){
     if( db->init.busy ) {
       sqlite3ErrorMsg(pParse, "corrupt database");
       pParse->nErr++;
@@ -61929,8 +80909,9 @@ SQLITE_PRIVATE void sqlite3StartTable(
   */
   iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
   if( iDb<0 ) return;
-  if( !OMIT_TEMPDB && isTemp && iDb>1 ){
-    /* If creating a temp table, the name may not be qualified */
+  if( !OMIT_TEMPDB && isTemp && pName2->n>0 && iDb!=1 ){
+    /* If creating a temp table, the name may not be qualified. Unless 
+    ** the database name is "temp" anyway.  */
     sqlite3ErrorMsg(pParse, "temporary table name must be unqualified");
     return;
   }
@@ -61978,17 +80959,21 @@ SQLITE_PRIVATE void sqlite3StartTable(
   ** collisions.
   */
   if( !IN_DECLARE_VTAB ){
+    char *zDb = db->aDb[iDb].zName;
     if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
       goto begin_table_error;
     }
-    pTable = sqlite3FindTable(db, zName, db->aDb[iDb].zName);
+    pTable = sqlite3FindTable(db, zName, zDb);
     if( pTable ){
       if( !noErr ){
         sqlite3ErrorMsg(pParse, "table %T already exists", pName);
+      }else{
+        assert( !db->init.busy );
+        sqlite3CodeVerifySchema(pParse, iDb);
       }
       goto begin_table_error;
     }
-    if( sqlite3FindIndex(db, zName, 0)!=0 && (iDb==0 || !db->init.busy) ){
+    if( sqlite3FindIndex(db, zName, zDb)!=0 ){
       sqlite3ErrorMsg(pParse, "there is already an index named %s", zName);
       goto begin_table_error;
     }
@@ -62005,8 +80990,8 @@ SQLITE_PRIVATE void sqlite3StartTable(
   pTable->iPKey = -1;
   pTable->pSchema = db->aDb[iDb].pSchema;
   pTable->nRef = 1;
-  pTable->db = db;
-  if( pParse->pNewTable ) sqlite3DeleteTable(pParse->pNewTable);
+  pTable->nRowEst = 1000000;
+  assert( pParse->pNewTable==0 );
   pParse->pNewTable = pTable;
 
   /* If this is the magic sqlite_sequence table used by autoincrement,
@@ -62015,6 +81000,7 @@ SQLITE_PRIVATE void sqlite3StartTable(
   */
 #ifndef SQLITE_OMIT_AUTOINCREMENT
   if( !pParse->nested && strcmp(zName, "sqlite_sequence")==0 ){
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
     pTable->pSchema->pSeqTab = pTable;
   }
 #endif
@@ -62045,24 +81031,25 @@ SQLITE_PRIVATE void sqlite3StartTable(
     reg1 = pParse->regRowid = ++pParse->nMem;
     reg2 = pParse->regRoot = ++pParse->nMem;
     reg3 = ++pParse->nMem;
-    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, reg3, 1);   /* file_format */
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, reg3, BTREE_FILE_FORMAT);
     sqlite3VdbeUsesBtree(v, iDb);
     j1 = sqlite3VdbeAddOp1(v, OP_If, reg3);
     fileFormat = (db->flags & SQLITE_LegacyFileFmt)!=0 ?
                   1 : SQLITE_MAX_FILE_FORMAT;
     sqlite3VdbeAddOp2(v, OP_Integer, fileFormat, reg3);
-    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 1, reg3);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, reg3);
     sqlite3VdbeAddOp2(v, OP_Integer, ENC(db), reg3);
-    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 4, reg3);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_TEXT_ENCODING, reg3);
     sqlite3VdbeJumpHere(v, j1);
 
     /* This just creates a place-holder record in the sqlite_master table.
     ** The record created does not contain anything yet.  It will be replaced
     ** by the real entry in code generated at sqlite3EndTable().
     **
-    ** The rowid for the new entry is left on the top of the stack.
-    ** The rowid value is needed by the code that sqlite3EndTable will
-    ** generate.
+    ** The rowid for the new entry is left in register pParse->regRowid.
+    ** The root page number of the new table is left in reg pParse->regRoot.
+    ** The rowid and root page number values are needed by the code that
+    ** sqlite3EndTable will generate.
     */
 #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
     if( isView || isVirtual ){
@@ -62161,10 +81148,9 @@ SQLITE_PRIVATE void sqlite3AddColumn(Parse *pParse, Token *pName){
 */
 SQLITE_PRIVATE void sqlite3AddNotNull(Parse *pParse, int onError){
   Table *p;
-  int i;
-  if( (p = pParse->pNewTable)==0 ) return;
-  i = p->nCol-1;
-  if( i>=0 ) p->aCol[i].notNull = (u8)onError;
+  p = pParse->pNewTable;
+  if( p==0 || NEVER(p->nCol<1) ) return;
+  p->aCol[p->nCol-1].notNull = (u8)onError;
 }
 
 /*
@@ -62192,14 +81178,12 @@ SQLITE_PRIVATE void sqlite3AddNotNull(Parse *pParse, int onError){
 ** If none of the substrings in the above table are found,
 ** SQLITE_AFF_NUMERIC is returned.
 */
-SQLITE_PRIVATE char sqlite3AffinityType(const Token *pType){
+SQLITE_PRIVATE char sqlite3AffinityType(const char *zIn){
   u32 h = 0;
   char aff = SQLITE_AFF_NUMERIC;
-  const unsigned char *zIn = pType->z;
-  const unsigned char *zEnd = &pType->z[pType->n];
 
-  while( zIn!=zEnd ){
-    h = (h<<8) + sqlite3UpperToLower[*zIn];
+  if( zIn ) while( zIn[0] ){
+    h = (h<<8) + sqlite3UpperToLower[(*zIn)&0xff];
     zIn++;
     if( h==(('c'<<24)+('h'<<16)+('a'<<8)+'r') ){             /* CHAR */
       aff = SQLITE_AFF_TEXT; 
@@ -62241,18 +81225,14 @@ SQLITE_PRIVATE char sqlite3AffinityType(const Token *pType){
 */ 
 SQLITE_PRIVATE void sqlite3AddColumnType(Parse *pParse, Token *pType){
   Table *p;
-  int i;
   Column *pCol;
-  sqlite3 *db;
 
-  if( (p = pParse->pNewTable)==0 ) return;
-  i = p->nCol-1;
-  if( i<0 ) return;
-  pCol = &p->aCol[i];
-  db = pParse->db;
-  sqlite3DbFree(db, pCol->zType);
-  pCol->zType = sqlite3NameFromToken(db, pType);
-  pCol->affinity = sqlite3AffinityType(pType);
+  p = pParse->pNewTable;
+  if( p==0 || NEVER(p->nCol<1) ) return;
+  pCol = &p->aCol[p->nCol-1];
+  assert( pCol->zType==0 );
+  pCol->zType = sqlite3NameFromToken(pParse->db, pType);
+  pCol->affinity = sqlite3AffinityType(pCol->zType);
 }
 
 /*
@@ -62265,25 +81245,29 @@ SQLITE_PRIVATE void sqlite3AddColumnType(Parse *pParse, Token *pType){
 ** This routine is called by the parser while in the middle of
 ** parsing a CREATE TABLE statement.
 */
-SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse *pParse, Expr *pExpr){
+SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse *pParse, ExprSpan *pSpan){
   Table *p;
   Column *pCol;
   sqlite3 *db = pParse->db;
-  if( (p = pParse->pNewTable)!=0 ){
+  p = pParse->pNewTable;
+  if( p!=0 ){
     pCol = &(p->aCol[p->nCol-1]);
-    if( !sqlite3ExprIsConstantOrFunction(pExpr) ){
+    if( !sqlite3ExprIsConstantOrFunction(pSpan->pExpr) ){
       sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
           pCol->zName);
     }else{
-      Expr *pCopy;
+      /* A copy of pExpr is used instead of the original, as pExpr contains
+      ** tokens that point to volatile memory. The 'span' of the expression
+      ** is required by pragma table_info.
+      */
       sqlite3ExprDelete(db, pCol->pDflt);
-      pCol->pDflt = pCopy = sqlite3ExprDup(db, pExpr);
-      if( pCopy ){
-        sqlite3TokenCopy(db, &pCopy->span, &pExpr->span);
-      }
+      pCol->pDflt = sqlite3ExprDup(db, pSpan->pExpr, EXPRDUP_REDUCE);
+      sqlite3DbFree(db, pCol->zDflt);
+      pCol->zDflt = sqlite3DbStrNDup(db, (char*)pSpan->zStart,
+                                     (int)(pSpan->zEnd - pSpan->zStart));
     }
   }
-  sqlite3ExprDelete(db, pExpr);
+  sqlite3ExprDelete(db, pSpan->pExpr);
 }
 
 /*
@@ -62352,7 +81336,11 @@ SQLITE_PRIVATE void sqlite3AddPrimaryKey(
        "INTEGER PRIMARY KEY");
 #endif
   }else{
-    sqlite3CreateIndex(pParse, 0, 0, 0, pList, onError, 0, 0, sortOrder, 0);
+    Index *p;
+    p = sqlite3CreateIndex(pParse, 0, 0, 0, pList, onError, 0, 0, sortOrder, 0);
+    if( p ){
+      p->autoIndex = 2;
+    }
     pList = 0;
   }
 
@@ -62368,18 +81356,18 @@ SQLITE_PRIVATE void sqlite3AddCheckConstraint(
   Parse *pParse,    /* Parsing context */
   Expr *pCheckExpr  /* The check expression */
 ){
-  sqlite3 *db = pParse->db;
 #ifndef SQLITE_OMIT_CHECK
   Table *pTab = pParse->pNewTable;
   if( pTab && !IN_DECLARE_VTAB ){
-    /* The CHECK expression must be duplicated so that tokens refer
-    ** to malloced space and not the (ephemeral) text of the CREATE TABLE
-    ** statement */
-    pTab->pCheck = sqlite3ExprAnd(db, pTab->pCheck, 
-                                  sqlite3ExprDup(db, pCheckExpr));
-  }
+    pTab->pCheck = sqlite3ExprListAppend(pParse, pTab->pCheck, pCheckExpr);
+    if( pParse->constraintName.n ){
+      sqlite3ExprListSetName(pParse, pTab->pCheck, &pParse->constraintName, 1);
+    }
+  }else
 #endif
-  sqlite3ExprDelete(db, pCheckExpr);
+  {
+    sqlite3ExprDelete(pParse->db, pCheckExpr);
+  }
 }
 
 /*
@@ -62398,7 +81386,7 @@ SQLITE_PRIVATE void sqlite3AddCollateType(Parse *pParse, Token *pToken){
   zColl = sqlite3NameFromToken(db, pToken);
   if( !zColl ) return;
 
-  if( sqlite3LocateCollSeq(pParse, zColl, -1) ){
+  if( sqlite3LocateCollSeq(pParse, zColl) ){
     Index *pIdx;
     p->aCol[i].zColl = zColl;
   
@@ -62434,22 +81422,20 @@ SQLITE_PRIVATE void sqlite3AddCollateType(Parse *pParse, Token *pToken){
 ** This routine is a wrapper around sqlite3FindCollSeq().  This routine
 ** invokes the collation factory if the named collation cannot be found
 ** and generates an error message.
+**
+** See also: sqlite3FindCollSeq(), sqlite3GetCollSeq()
 */
-SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName){
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName){
   sqlite3 *db = pParse->db;
   u8 enc = ENC(db);
   u8 initbusy = db->init.busy;
   CollSeq *pColl;
 
-  pColl = sqlite3FindCollSeq(db, enc, zName, nName, initbusy);
+  pColl = sqlite3FindCollSeq(db, enc, zName, initbusy);
   if( !initbusy && (!pColl || !pColl->xCmp) ){
-    pColl = sqlite3GetCollSeq(db, pColl, zName, nName);
+    pColl = sqlite3GetCollSeq(db, enc, pColl, zName);
     if( !pColl ){
-      if( nName<0 ){
-        nName = sqlite3Strlen(db, zName);
-      }
-      sqlite3ErrorMsg(pParse, "no such collation sequence: %.*s", nName, zName);
-      pColl = 0;
+      sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
     }
   }
 
@@ -62477,8 +81463,9 @@ SQLITE_PRIVATE void sqlite3ChangeCookie(Parse *pParse, int iDb){
   int r1 = sqlite3GetTempReg(pParse);
   sqlite3 *db = pParse->db;
   Vdbe *v = pParse->pVdbe;
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
   sqlite3VdbeAddOp2(v, OP_Integer, db->aDb[iDb].pSchema->schema_cookie+1, r1);
-  sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 0, r1);
+  sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_SCHEMA_VERSION, r1);
   sqlite3ReleaseTempReg(pParse, r1);
 }
 
@@ -62499,18 +81486,31 @@ static int identLength(const char *z){
 }
 
 /*
-** Write an identifier onto the end of the given string.  Add
-** quote characters as needed.
+** The first parameter is a pointer to an output buffer. The second 
+** parameter is a pointer to an integer that contains the offset at
+** which to write into the output buffer. This function copies the
+** nul-terminated string pointed to by the third parameter, zSignedIdent,
+** to the specified offset in the buffer and updates *pIdx to refer
+** to the first byte after the last byte written before returning.
+** 
+** If the string zSignedIdent consists entirely of alpha-numeric
+** characters, does not begin with a digit and is not an SQL keyword,
+** then it is copied to the output buffer exactly as it is. Otherwise,
+** it is quoted using double-quotes.
 */
 static void identPut(char *z, int *pIdx, char *zSignedIdent){
   unsigned char *zIdent = (unsigned char*)zSignedIdent;
   int i, j, needQuote;
   i = *pIdx;
+
   for(j=0; zIdent[j]; j++){
-    if( !isalnum(zIdent[j]) && zIdent[j]!='_' ) break;
+    if( !sqlite3Isalnum(zIdent[j]) && zIdent[j]!='_' ) break;
   }
-  needQuote =  zIdent[j]!=0 || isdigit(zIdent[0])
-                  || sqlite3KeywordCode(zIdent, j)!=TK_ID;
+  needQuote = sqlite3Isdigit(zIdent[0]) || sqlite3KeywordCode(zIdent, j)!=TK_ID;
+  if( !needQuote ){
+    needQuote = zIdent[j];
+  }
+
   if( needQuote ) z[i++] = '"';
   for(j=0; zIdent[j]; j++){
     z[i++] = zIdent[j];
@@ -62526,21 +81526,17 @@ static void identPut(char *z, int *pIdx, char *zSignedIdent){
 ** table.  Memory to hold the text of the statement is obtained
 ** from sqliteMalloc() and must be freed by the calling function.
 */
-static char *createTableStmt(sqlite3 *db, Table *p, int isTemp){
+static char *createTableStmt(sqlite3 *db, Table *p){
   int i, k, n;
   char *zStmt;
-  char *zSep, *zSep2, *zEnd, *z;
+  char *zSep, *zSep2, *zEnd;
   Column *pCol;
   n = 0;
   for(pCol = p->aCol, i=0; i<p->nCol; i++, pCol++){
-    n += identLength(pCol->zName);
-    z = pCol->zType;
-    if( z ){
-      n += (sqlite3Strlen30(z) + 1);
-    }
+    n += identLength(pCol->zName) + 5;
   }
   n += identLength(p->zName);
-  if( n<50 ){
+  if( n<50 ){ 
     zSep = "";
     zSep2 = ",";
     zEnd = ")";
@@ -62550,27 +81546,45 @@ static char *createTableStmt(sqlite3 *db, Table *p, int isTemp){
     zEnd = "\n)";
   }
   n += 35 + 6*p->nCol;
-  zStmt = sqlite3Malloc( n );
+  zStmt = sqlite3DbMallocRaw(0, n);
   if( zStmt==0 ){
     db->mallocFailed = 1;
     return 0;
   }
-  sqlite3_snprintf(n, zStmt,
-                  !OMIT_TEMPDB&&isTemp ? "CREATE TEMP TABLE ":"CREATE TABLE ");
+  sqlite3_snprintf(n, zStmt, "CREATE TABLE ");
   k = sqlite3Strlen30(zStmt);
   identPut(zStmt, &k, p->zName);
   zStmt[k++] = '(';
   for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
+    static const char * const azType[] = {
+        /* SQLITE_AFF_TEXT    */ " TEXT",
+        /* SQLITE_AFF_NONE    */ "",
+        /* SQLITE_AFF_NUMERIC */ " NUM",
+        /* SQLITE_AFF_INTEGER */ " INT",
+        /* SQLITE_AFF_REAL    */ " REAL"
+    };
+    int len;
+    const char *zType;
+
     sqlite3_snprintf(n-k, &zStmt[k], zSep);
     k += sqlite3Strlen30(&zStmt[k]);
     zSep = zSep2;
     identPut(zStmt, &k, pCol->zName);
-    if( (z = pCol->zType)!=0 ){
-      zStmt[k++] = ' ';
-      assert( (int)(sqlite3Strlen30(z)+k+1)<=n );
-      sqlite3_snprintf(n-k, &zStmt[k], "%s", z);
-      k += sqlite3Strlen30(z);
-    }
+    assert( pCol->affinity-SQLITE_AFF_TEXT >= 0 );
+    assert( pCol->affinity-SQLITE_AFF_TEXT < ArraySize(azType) );
+    testcase( pCol->affinity==SQLITE_AFF_TEXT );
+    testcase( pCol->affinity==SQLITE_AFF_NONE );
+    testcase( pCol->affinity==SQLITE_AFF_NUMERIC );
+    testcase( pCol->affinity==SQLITE_AFF_INTEGER );
+    testcase( pCol->affinity==SQLITE_AFF_REAL );
+    
+    zType = azType[pCol->affinity - SQLITE_AFF_TEXT];
+    len = sqlite3Strlen30(zType);
+    assert( pCol->affinity==SQLITE_AFF_NONE 
+            || pCol->affinity==sqlite3AffinityType(zType) );
+    memcpy(&zStmt[k], zType, len);
+    k += len;
+    assert( k<=n );
   }
   sqlite3_snprintf(n-k, &zStmt[k], "%s", zEnd);
   return zStmt;
@@ -62606,7 +81620,7 @@ SQLITE_PRIVATE void sqlite3EndTable(
   sqlite3 *db = pParse->db;
   int iDb;
 
-  if( (pEnd==0 && pSelect==0) || pParse->nErr || db->mallocFailed ) {
+  if( (pEnd==0 && pSelect==0) || db->mallocFailed ){
     return;
   }
   p = pParse->pNewTable;
@@ -62622,6 +81636,8 @@ SQLITE_PRIVATE void sqlite3EndTable(
   if( p->pCheck ){
     SrcList sSrc;                   /* Fake SrcList for pParse->pNewTable */
     NameContext sNC;                /* Name context for pParse->pNewTable */
+    ExprList *pList;                /* List of all CHECK constraints */
+    int i;                          /* Loop counter */
 
     memset(&sNC, 0, sizeof(sNC));
     memset(&sSrc, 0, sizeof(sSrc));
@@ -62631,9 +81647,12 @@ SQLITE_PRIVATE void sqlite3EndTable(
     sSrc.a[0].iCursor = -1;
     sNC.pParse = pParse;
     sNC.pSrcList = &sSrc;
-    sNC.isCheck = 1;
-    if( sqlite3ResolveExprNames(&sNC, p->pCheck) ){
-      return;
+    sNC.ncFlags = NC_IsCheck;
+    pList = p->pCheck;
+    for(i=0; i<pList->nExpr; i++){
+      if( sqlite3ResolveExprNames(&sNC, pList->a[i].pExpr) ){
+        return;
+      }
     }
   }
 #endif /* !defined(SQLITE_OMIT_CHECK) */
@@ -62649,8 +81668,7 @@ SQLITE_PRIVATE void sqlite3EndTable(
   }
 
   /* If not initializing, then create a record for the new table
-  ** in the SQLITE_MASTER table of the database.  The record number
-  ** for the new table entry should already be on the stack.
+  ** in the SQLITE_MASTER table of the database.
   **
   ** If this is a TEMPORARY table, write the entry into the auxiliary
   ** file instead of into the main database file.
@@ -62663,13 +81681,12 @@ SQLITE_PRIVATE void sqlite3EndTable(
     char *zStmt;    /* Text of the CREATE TABLE or CREATE VIEW statement */
 
     v = sqlite3GetVdbe(pParse);
-    if( v==0 ) return;
+    if( NEVER(v==0) ) return;
 
     sqlite3VdbeAddOp1(v, OP_Close, 0);
 
-    /* Create the rootpage for the new table and push it onto the stack.
-    ** A view has no rootpage, so just push a zero onto the stack for
-    ** views.  Initialize zType at the same time.
+    /* 
+    ** Initialize zType for the new view or table.
     */
     if( p->pSelect==0 ){
       /* A regular table */
@@ -62685,7 +81702,7 @@ SQLITE_PRIVATE void sqlite3EndTable(
 
     /* If this is a CREATE TABLE xx AS SELECT ..., execute the SELECT
     ** statement to populate the new table. The root-page number for the
-    ** new table is on the top of the vdbe stack.
+    ** new table is in register pParse->regRoot.
     **
     ** Once the SELECT has been coded by sqlite3Select(), it is in a
     ** suitable state to query for the column names and types to be used
@@ -62700,9 +81717,9 @@ SQLITE_PRIVATE void sqlite3EndTable(
       SelectDest dest;
       Table *pSelTab;
 
-      assert(pParse->nTab==0);
+      assert(pParse->nTab==1);
       sqlite3VdbeAddOp3(v, OP_OpenWrite, 1, pParse->regRoot, iDb);
-      sqlite3VdbeChangeP5(v, 1);
+      sqlite3VdbeChangeP5(v, OPFLAG_P2ISREG);
       pParse->nTab = 2;
       sqlite3SelectDestInit(&dest, SRT_Table, 1);
       sqlite3Select(pParse, pSelect, &dest);
@@ -62715,13 +81732,13 @@ SQLITE_PRIVATE void sqlite3EndTable(
         p->aCol = pSelTab->aCol;
         pSelTab->nCol = 0;
         pSelTab->aCol = 0;
-        sqlite3DeleteTable(pSelTab);
+        sqlite3DeleteTable(db, pSelTab);
       }
     }
 
     /* Compute the complete text of the CREATE statement */
     if( pSelect ){
-      zStmt = createTableStmt(db, p, p->pSchema==db->aDb[1].pSchema);
+      zStmt = createTableStmt(db, p);
     }else{
       n = (int)(pEnd->z - pParse->sNameToken.z) + 1;
       zStmt = sqlite3MPrintf(db, 
@@ -62731,9 +81748,7 @@ SQLITE_PRIVATE void sqlite3EndTable(
 
     /* A slot for the record has already been allocated in the 
     ** SQLITE_MASTER table.  We just need to update that slot with all
-    ** the information we've collected.  The rowid for the preallocated
-    ** slot is the 2nd item on the stack.  The top of the stack is the
-    ** root page for the new table (or a 0 if this is a view).
+    ** the information we've collected.
     */
     sqlite3NestedParse(pParse,
       "UPDATE %Q.%s "
@@ -62756,6 +81771,7 @@ SQLITE_PRIVATE void sqlite3EndTable(
     */
     if( p->tabFlags & TF_Autoincrement ){
       Db *pDb = &db->aDb[iDb];
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
       if( pDb->pSchema->pSeqTab==0 ){
         sqlite3NestedParse(pParse,
           "CREATE TABLE %Q.sqlite_sequence(name,seq)",
@@ -62766,37 +81782,25 @@ SQLITE_PRIVATE void sqlite3EndTable(
 #endif
 
     /* Reparse everything to update our internal data structures */
-    sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0,
-        sqlite3MPrintf(db, "tbl_name='%q'",p->zName), P4_DYNAMIC);
+    sqlite3VdbeAddParseSchemaOp(v, iDb,
+               sqlite3MPrintf(db, "tbl_name='%q'", p->zName));
   }
 
 
   /* Add the table to the in-memory representation of the database.
   */
-  if( db->init.busy && pParse->nErr==0 ){
+  if( db->init.busy ){
     Table *pOld;
-    FKey *pFKey; 
     Schema *pSchema = p->pSchema;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
     pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName,
-                             sqlite3Strlen30(p->zName)+1,p);
+                             sqlite3Strlen30(p->zName),p);
     if( pOld ){
       assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
       db->mallocFailed = 1;
       return;
     }
-#ifndef SQLITE_OMIT_FOREIGN_KEY
-    for(pFKey=p->pFKey; pFKey; pFKey=pFKey->pNextFrom){
-      void *data;
-      int nTo = sqlite3Strlen30(pFKey->zTo) + 1;
-      pFKey->pNextTo = sqlite3HashFind(&pSchema->aFKey, pFKey->zTo, nTo);
-      data = sqlite3HashInsert(&pSchema->aFKey, pFKey->zTo, nTo, pFKey);
-      if( data==(void *)pFKey ){
-        db->mallocFailed = 1;
-      }
-    }
-#endif
     pParse->pNewTable = 0;
-    db->nTable++;
     db->flags |= SQLITE_InternChanges;
 
 #ifndef SQLITE_OMIT_ALTERTABLE
@@ -62829,10 +81833,10 @@ SQLITE_PRIVATE void sqlite3CreateView(
 ){
   Table *p;
   int n;
-  const unsigned char *z;
+  const char *z;
   Token sEnd;
   DbFixer sFix;
-  Token *pName;
+  Token *pName = 0;
   int iDb;
   sqlite3 *db = pParse->db;
 
@@ -62861,7 +81865,7 @@ SQLITE_PRIVATE void sqlite3CreateView(
   ** allocated rather than point to the input string - which means that
   ** they will persist after the current sqlite3_exec() call returns.
   */
-  p->pSelect = sqlite3SelectDup(db, pSelect);
+  p->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
   sqlite3SelectDelete(db, pSelect);
   if( db->mallocFailed ){
     return;
@@ -62874,13 +81878,13 @@ SQLITE_PRIVATE void sqlite3CreateView(
   ** the end.
   */
   sEnd = pParse->sLastToken;
-  if( sEnd.z[0]!=0 && sEnd.z[0]!=';' ){
+  if( ALWAYS(sEnd.z[0]!=0) && sEnd.z[0]!=';' ){
     sEnd.z += sEnd.n;
   }
   sEnd.n = 0;
   n = (int)(sEnd.z - pBegin->z);
-  z = (const unsigned char*)pBegin->z;
-  while( n>0 && (z[n-1]==';' || isspace(z[n-1])) ){ n--; }
+  z = pBegin->z;
+  while( ALWAYS(n>0) && sqlite3Isspace(z[n-1]) ){ n--; }
   sEnd.z = &z[n-1];
   sEnd.n = 1;
 
@@ -62926,8 +81930,13 @@ SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
   **     CREATE VIEW one AS SELECT * FROM two;
   **     CREATE VIEW two AS SELECT * FROM one;
   **
-  ** Actually, this error is caught previously and so the following test
-  ** should always fail.  But we will leave it in place just to be safe.
+  ** Actually, the error above is now caught prior to reaching this point.
+  ** But the following test is still important as it does come up
+  ** in the following:
+  ** 
+  **     CREATE TABLE main.ex1(a);
+  **     CREATE TEMP VIEW ex1 AS SELECT a FROM ex1;
+  **     SELECT * FROM temp.ex1;
   */
   if( pTable->nCol<0 ){
     sqlite3ErrorMsg(pParse, "view %s is circularly defined", pTable->zName);
@@ -62943,11 +81952,13 @@ SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
   ** statement that defines the view.
   */
   assert( pTable->pSelect );
-  pSel = sqlite3SelectDup(db, pTable->pSelect);
+  pSel = sqlite3SelectDup(db, pTable->pSelect, 0);
   if( pSel ){
+    u8 enableLookaside = db->lookaside.bEnabled;
     n = pParse->nTab;
     sqlite3SrcListAssignCursors(pParse, pSel->pSrc);
     pTable->nCol = -1;
+    db->lookaside.bEnabled = 0;
 #ifndef SQLITE_OMIT_AUTHORIZATION
     xAuth = db->xAuth;
     db->xAuth = 0;
@@ -62956,6 +81967,7 @@ SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
 #else
     pSelTab = sqlite3ResultSetOfSelect(pParse, pSel);
 #endif
+    db->lookaside.bEnabled = enableLookaside;
     pParse->nTab = n;
     if( pSelTab ){
       assert( pTable->aCol==0 );
@@ -62963,7 +81975,8 @@ SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
       pTable->aCol = pSelTab->aCol;
       pSelTab->nCol = 0;
       pSelTab->aCol = 0;
-      sqlite3DeleteTable(pSelTab);
+      sqlite3DeleteTable(db, pSelTab);
+      assert( sqlite3SchemaMutexHeld(db, 0, pTable->pSchema) );
       pTable->pSchema->flags |= DB_UnresetViews;
     }else{
       pTable->nCol = 0;
@@ -62984,11 +81997,14 @@ SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
 */
 static void sqliteViewResetAll(sqlite3 *db, int idx){
   HashElem *i;
+  assert( sqlite3SchemaMutexHeld(db, idx, 0) );
   if( !DbHasProperty(db, idx, DB_UnresetViews) ) return;
   for(i=sqliteHashFirst(&db->aDb[idx].pSchema->tblHash); i;i=sqliteHashNext(i)){
     Table *pTab = sqliteHashData(i);
     if( pTab->pSelect ){
-      sqliteResetColumnNames(pTab);
+      sqliteDeleteColumnNames(db, pTab);
+      pTab->aCol = 0;
+      pTab->nCol = 0;
     }
   }
   DbClearProperty(db, idx, DB_UnresetViews);
@@ -63015,10 +82031,13 @@ static void sqliteViewResetAll(sqlite3 *db, int idx){
 ** in order to be certain that we got the right one.
 */
 #ifndef SQLITE_OMIT_AUTOVACUUM
-SQLITE_PRIVATE void sqlite3RootPageMoved(Db *pDb, int iFrom, int iTo){
+SQLITE_PRIVATE void sqlite3RootPageMoved(sqlite3 *db, int iDb, int iFrom, int iTo){
   HashElem *pElem;
   Hash *pHash;
+  Db *pDb;
 
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pDb = &db->aDb[iDb];
   pHash = &pDb->pSchema->tblHash;
   for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
     Table *pTab = sqliteHashData(pElem);
@@ -63046,14 +82065,16 @@ static void destroyRootPage(Parse *pParse, int iTable, int iDb){
   Vdbe *v = sqlite3GetVdbe(pParse);
   int r1 = sqlite3GetTempReg(pParse);
   sqlite3VdbeAddOp3(v, OP_Destroy, iTable, r1, iDb);
+  sqlite3MayAbort(pParse);
 #ifndef SQLITE_OMIT_AUTOVACUUM
   /* OP_Destroy stores an in integer r1. If this integer
   ** is non-zero, then it is the root page number of a table moved to
   ** location iTable. The following code modifies the sqlite_master table to
   ** reflect this.
   **
-  ** The "#%d" in the SQL is a special constant that means whatever value
-  ** is on the top of the stack.  See sqlite3RegisterExpr().
+  ** The "#NNN" in the SQL is a special constant that means whatever value
+  ** is in register NNN.  See grammar rules associated with the TK_REGISTER
+  ** token for additional information.
   */
   sqlite3NestedParse(pParse, 
      "UPDATE %Q.%s SET rootpage=%d WHERE #%d AND rootpage=#%d",
@@ -63121,6 +82142,100 @@ static void destroyTable(Parse *pParse, Table *pTab){
 #endif
 }
 
+/*
+** Remove entries from the sqlite_statN tables (for N in (1,2,3))
+** after a DROP INDEX or DROP TABLE command.
+*/
+static void sqlite3ClearStatTables(
+  Parse *pParse,         /* The parsing context */
+  int iDb,               /* The database number */
+  const char *zType,     /* "idx" or "tbl" */
+  const char *zName      /* Name of index or table */
+){
+  int i;
+  const char *zDbName = pParse->db->aDb[iDb].zName;
+  for(i=1; i<=3; i++){
+    char zTab[24];
+    sqlite3_snprintf(sizeof(zTab),zTab,"sqlite_stat%d",i);
+    if( sqlite3FindTable(pParse->db, zTab, zDbName) ){
+      sqlite3NestedParse(pParse,
+        "DELETE FROM %Q.%s WHERE %s=%Q",
+        zDbName, zTab, zType, zName
+      );
+    }
+  }
+}
+
+/*
+** Generate code to drop a table.
+*/
+SQLITE_PRIVATE void sqlite3CodeDropTable(Parse *pParse, Table *pTab, int iDb, int isView){
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  Trigger *pTrigger;
+  Db *pDb = &db->aDb[iDb];
+
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );
+  sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3VdbeAddOp0(v, OP_VBegin);
+  }
+#endif
+
+  /* Drop all triggers associated with the table being dropped. Code
+  ** is generated to remove entries from sqlite_master and/or
+  ** sqlite_temp_master if required.
+  */
+  pTrigger = sqlite3TriggerList(pParse, pTab);
+  while( pTrigger ){
+    assert( pTrigger->pSchema==pTab->pSchema || 
+        pTrigger->pSchema==db->aDb[1].pSchema );
+    sqlite3DropTriggerPtr(pParse, pTrigger);
+    pTrigger = pTrigger->pNext;
+  }
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  /* Remove any entries of the sqlite_sequence table associated with
+  ** the table being dropped. This is done before the table is dropped
+  ** at the btree level, in case the sqlite_sequence table needs to
+  ** move as a result of the drop (can happen in auto-vacuum mode).
+  */
+  if( pTab->tabFlags & TF_Autoincrement ){
+    sqlite3NestedParse(pParse,
+      "DELETE FROM %Q.sqlite_sequence WHERE name=%Q",
+      pDb->zName, pTab->zName
+    );
+  }
+#endif
+
+  /* Drop all SQLITE_MASTER table and index entries that refer to the
+  ** table. The program name loops through the master table and deletes
+  ** every row that refers to a table of the same name as the one being
+  ** dropped. Triggers are handled seperately because a trigger can be
+  ** created in the temp database that refers to a table in another
+  ** database.
+  */
+  sqlite3NestedParse(pParse, 
+      "DELETE FROM %Q.%s WHERE tbl_name=%Q and type!='trigger'",
+      pDb->zName, SCHEMA_TABLE(iDb), pTab->zName);
+  if( !isView && !IsVirtual(pTab) ){
+    destroyTable(pParse, pTab);
+  }
+
+  /* Remove the table entry from SQLite's internal schema and modify
+  ** the schema cookie.
+  */
+  if( IsVirtual(pTab) ){
+    sqlite3VdbeAddOp4(v, OP_VDestroy, iDb, 0, 0, pTab->zName, 0);
+  }
+  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
+  sqlite3ChangeCookie(pParse, iDb);
+  sqliteViewResetAll(db, iDb);
+}
+
 /*
 ** This routine is called to do the work of a DROP TABLE statement.
 ** pName is the name of the table to be dropped.
@@ -63131,17 +82246,18 @@ SQLITE_PRIVATE void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView,
   sqlite3 *db = pParse->db;
   int iDb;
 
-  if( pParse->nErr || db->mallocFailed ){
+  if( db->mallocFailed ){
     goto exit_drop_table;
   }
+  assert( pParse->nErr==0 );
   assert( pName->nSrc==1 );
+  if( noErr ) db->suppressErr++;
   pTab = sqlite3LocateTable(pParse, isView, 
                             pName->a[0].zName, pName->a[0].zDatabase);
+  if( noErr ) db->suppressErr--;
 
   if( pTab==0 ){
-    if( noErr ){
-      sqlite3ErrorClear(pParse);
-    }
+    if( noErr ) sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
     goto exit_drop_table;
   }
   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
@@ -63171,7 +82287,7 @@ SQLITE_PRIVATE void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView,
 #ifndef SQLITE_OMIT_VIRTUALTABLE
     }else if( IsVirtual(pTab) ){
       code = SQLITE_DROP_VTABLE;
-      zArg2 = pTab->pMod->zName;
+      zArg2 = sqlite3GetVTable(db, pTab)->pMod->zName;
 #endif
     }else{
       if( !OMIT_TEMPDB && iDb==1 ){
@@ -63188,7 +82304,8 @@ SQLITE_PRIVATE void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView,
     }
   }
 #endif
-  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 
+    && sqlite3StrNICmp(pTab->zName, "sqlite_stat", 11)!=0 ){
     sqlite3ErrorMsg(pParse, "table %s may not be dropped", pTab->zName);
     goto exit_drop_table;
   }
@@ -63212,76 +82329,11 @@ SQLITE_PRIVATE void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView,
   */
   v = sqlite3GetVdbe(pParse);
   if( v ){
-    Trigger *pTrigger;
-    Db *pDb = &db->aDb[iDb];
     sqlite3BeginWriteOperation(pParse, 1, iDb);
-
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-    if( IsVirtual(pTab) ){
-      if( v ){
-        sqlite3VdbeAddOp0(v, OP_VBegin);
-      }
-    }
-#endif
-
-    /* Drop all triggers associated with the table being dropped. Code
-    ** is generated to remove entries from sqlite_master and/or
-    ** sqlite_temp_master if required.
-    */
-    pTrigger = pTab->pTrigger;
-    while( pTrigger ){
-      assert( pTrigger->pSchema==pTab->pSchema || 
-          pTrigger->pSchema==db->aDb[1].pSchema );
-      sqlite3DropTriggerPtr(pParse, pTrigger);
-      pTrigger = pTrigger->pNext;
-    }
-
-#ifndef SQLITE_OMIT_AUTOINCREMENT
-    /* Remove any entries of the sqlite_sequence table associated with
-    ** the table being dropped. This is done before the table is dropped
-    ** at the btree level, in case the sqlite_sequence table needs to
-    ** move as a result of the drop (can happen in auto-vacuum mode).
-    */
-    if( pTab->tabFlags & TF_Autoincrement ){
-      sqlite3NestedParse(pParse,
-        "DELETE FROM %s.sqlite_sequence WHERE name=%Q",
-        pDb->zName, pTab->zName
-      );
-    }
-#endif
-
-    /* Drop all SQLITE_MASTER table and index entries that refer to the
-    ** table. The program name loops through the master table and deletes
-    ** every row that refers to a table of the same name as the one being
-    ** dropped. Triggers are handled seperately because a trigger can be
-    ** created in the temp database that refers to a table in another
-    ** database.
-    */
-    sqlite3NestedParse(pParse, 
-        "DELETE FROM %Q.%s WHERE tbl_name=%Q and type!='trigger'",
-        pDb->zName, SCHEMA_TABLE(iDb), pTab->zName);
-
-    /* Drop any statistics from the sqlite_stat1 table, if it exists */
-    if( sqlite3FindTable(db, "sqlite_stat1", db->aDb[iDb].zName) ){
-      sqlite3NestedParse(pParse,
-        "DELETE FROM %Q.sqlite_stat1 WHERE tbl=%Q", pDb->zName, pTab->zName
-      );
-    }
-
-    if( !isView && !IsVirtual(pTab) ){
-      destroyTable(pParse, pTab);
-    }
-
-    /* Remove the table entry from SQLite's internal schema and modify
-    ** the schema cookie.
-    */
-    if( IsVirtual(pTab) ){
-      sqlite3VdbeAddOp4(v, OP_VDestroy, iDb, 0, 0, pTab->zName, 0);
-    }
-    sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
-    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3ClearStatTables(pParse, iDb, "tbl", pTab->zName);
+    sqlite3FkDropTable(pParse, pName, pTab);
+    sqlite3CodeDropTable(pParse, pTab, iDb, isView);
   }
-  sqliteViewResetAll(db, iDb);
 
 exit_drop_table:
   sqlite3SrcListDelete(db, pName);
@@ -63298,9 +82350,7 @@ exit_drop_table:
 ** in the ON DELETE, ON UPDATE and ON INSERT clauses.
 **
 ** An FKey structure is created and added to the table currently
-** under construction in the pParse->pNewTable field.  The new FKey
-** is not linked into db->aFKey at this point - that does not happen
-** until sqlite3EndTable().
+** under construction in the pParse->pNewTable field.
 **
 ** The foreign key is set for IMMEDIATE processing.  A subsequent call
 ** to sqlite3DeferForeignKey() might change this to DEFERRED.
@@ -63315,6 +82365,7 @@ SQLITE_PRIVATE void sqlite3CreateForeignKey(
   sqlite3 *db = pParse->db;
 #ifndef SQLITE_OMIT_FOREIGN_KEY
   FKey *pFKey = 0;
+  FKey *pNextTo;
   Table *p = pParse->pNewTable;
   int nByte;
   int i;
@@ -63322,10 +82373,10 @@ SQLITE_PRIVATE void sqlite3CreateForeignKey(
   char *z;
 
   assert( pTo!=0 );
-  if( p==0 || pParse->nErr || IN_DECLARE_VTAB ) goto fk_end;
+  if( p==0 || IN_DECLARE_VTAB ) goto fk_end;
   if( pFromCol==0 ){
     int iCol = p->nCol-1;
-    if( iCol<0 ) goto fk_end;
+    if( NEVER(iCol<0) ) goto fk_end;
     if( pToCol && pToCol->nExpr!=1 ){
       sqlite3ErrorMsg(pParse, "foreign key on %s"
          " should reference only one column of table %T",
@@ -63341,7 +82392,7 @@ SQLITE_PRIVATE void sqlite3CreateForeignKey(
   }else{
     nCol = pFromCol->nExpr;
   }
-  nByte = sizeof(*pFKey) + nCol*sizeof(pFKey->aCol[0]) + pTo->n + 1;
+  nByte = sizeof(*pFKey) + (nCol-1)*sizeof(pFKey->aCol[0]) + pTo->n + 1;
   if( pToCol ){
     for(i=0; i<pToCol->nExpr; i++){
       nByte += sqlite3Strlen30(pToCol->a[i].zName) + 1;
@@ -63353,14 +82404,12 @@ SQLITE_PRIVATE void sqlite3CreateForeignKey(
   }
   pFKey->pFrom = p;
   pFKey->pNextFrom = p->pFKey;
-  z = (char*)&pFKey[1];
-  pFKey->aCol = (struct sColMap*)z;
-  z += sizeof(struct sColMap)*nCol;
+  z = (char*)&pFKey->aCol[nCol];
   pFKey->zTo = z;
   memcpy(z, pTo->z, pTo->n);
   z[pTo->n] = 0;
+  sqlite3Dequote(z);
   z += pTo->n+1;
-  pFKey->pNextTo = 0;
   pFKey->nCol = nCol;
   if( pFromCol==0 ){
     pFKey->aCol[0].iFrom = p->nCol-1;
@@ -63391,9 +82440,22 @@ SQLITE_PRIVATE void sqlite3CreateForeignKey(
     }
   }
   pFKey->isDeferred = 0;
-  pFKey->deleteConf = (u8)(flags & 0xff);
-  pFKey->updateConf = (u8)((flags >> 8 ) & 0xff);
-  pFKey->insertConf = (u8)((flags >> 16 ) & 0xff);
+  pFKey->aAction[0] = (u8)(flags & 0xff);            /* ON DELETE action */
+  pFKey->aAction[1] = (u8)((flags >> 8 ) & 0xff);    /* ON UPDATE action */
+
+  assert( sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
+  pNextTo = (FKey *)sqlite3HashInsert(&p->pSchema->fkeyHash, 
+      pFKey->zTo, sqlite3Strlen30(pFKey->zTo), (void *)pFKey
+  );
+  if( pNextTo==pFKey ){
+    db->mallocFailed = 1;
+    goto fk_end;
+  }
+  if( pNextTo ){
+    assert( pNextTo->pPrevTo==0 );
+    pFKey->pNextTo = pNextTo;
+    pNextTo->pPrevTo = pFKey;
+  }
 
   /* Link the foreign key to the table as the last step.
   */
@@ -63419,7 +82481,7 @@ SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse *pParse, int isDeferred){
   Table *pTab;
   FKey *pFKey;
   if( (pTab = pParse->pNewTable)==0 || (pFKey = pTab->pFKey)==0 ) return;
-  assert( isDeferred==0 || isDeferred==1 );
+  assert( isDeferred==0 || isDeferred==1 ); /* EV: R-30323-21917 */
   pFKey->isDeferred = (u8)isDeferred;
 #endif
 }
@@ -63437,13 +82499,17 @@ SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse *pParse, int isDeferred){
 */
 static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
   Table *pTab = pIndex->pTable;  /* The table that is indexed */
-  int iTab = pParse->nTab;       /* Btree cursor used for pTab */
-  int iIdx = pParse->nTab+1;     /* Btree cursor used for pIndex */
+  int iTab = pParse->nTab++;     /* Btree cursor used for pTab */
+  int iIdx = pParse->nTab++;     /* Btree cursor used for pIndex */
+  int iSorter;                   /* Cursor opened by OpenSorter (if in use) */
   int addr1;                     /* Address of top of loop */
+  int addr2;                     /* Address to jump to for next iteration */
   int tnum;                      /* Root page of index */
   Vdbe *v;                       /* Generate code into this virtual machine */
   KeyInfo *pKey;                 /* KeyInfo for index */
+#ifdef SQLITE_OMIT_MERGE_SORT
   int regIdxKey;                 /* Registers containing the index key */
+#endif
   int regRecord;                 /* Register holding assemblied index record */
   sqlite3 *db = pParse->db;      /* The database connection */
   int iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
@@ -63469,32 +82535,73 @@ static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
   pKey = sqlite3IndexKeyinfo(pParse, pIndex);
   sqlite3VdbeAddOp4(v, OP_OpenWrite, iIdx, tnum, iDb, 
                     (char *)pKey, P4_KEYINFO_HANDOFF);
-  if( memRootPage>=0 ){
-    sqlite3VdbeChangeP5(v, 1);
-  }
+  sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR|((memRootPage>=0)?OPFLAG_P2ISREG:0));
+
+#ifndef SQLITE_OMIT_MERGE_SORT
+  /* Open the sorter cursor if we are to use one. */
+  iSorter = pParse->nTab++;
+  sqlite3VdbeAddOp4(v, OP_SorterOpen, iSorter, 0, 0, (char*)pKey, P4_KEYINFO);
+#else
+  iSorter = iTab;
+#endif
+
+  /* Open the table. Loop through all rows of the table, inserting index
+  ** records into the sorter. */
   sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
   addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
   regRecord = sqlite3GetTempReg(pParse);
-  regIdxKey = sqlite3GenerateIndexKey(pParse, pIndex, iTab, regRecord, 1);
-  if( pIndex->onError!=OE_None ){
-    int j1, j2;
-    int regRowid;
 
-    regRowid = regIdxKey + pIndex->nColumn;
-    j1 = sqlite3VdbeAddOp3(v, OP_IsNull, regIdxKey, 0, pIndex->nColumn);
-    j2 = sqlite3VdbeAddOp4(v, OP_IsUnique, iIdx,
-                           0, regRowid, SQLITE_INT_TO_PTR(regRecord), P4_INT32);
-    sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, OE_Abort, 0,
-                    "indexed columns are not unique", P4_STATIC);
-    sqlite3VdbeJumpHere(v, j1);
-    sqlite3VdbeJumpHere(v, j2);
-  }
-  sqlite3VdbeAddOp2(v, OP_IdxInsert, iIdx, regRecord);
-  sqlite3ReleaseTempReg(pParse, regRecord);
+#ifndef SQLITE_OMIT_MERGE_SORT
+  sqlite3GenerateIndexKey(pParse, pIndex, iTab, regRecord, 1);
+  sqlite3VdbeAddOp2(v, OP_SorterInsert, iSorter, regRecord);
   sqlite3VdbeAddOp2(v, OP_Next, iTab, addr1+1);
   sqlite3VdbeJumpHere(v, addr1);
+  addr1 = sqlite3VdbeAddOp2(v, OP_SorterSort, iSorter, 0);
+  if( pIndex->onError!=OE_None ){
+    int j2 = sqlite3VdbeCurrentAddr(v) + 3;
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, j2);
+    addr2 = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp3(v, OP_SorterCompare, iSorter, j2, regRecord);
+    sqlite3HaltConstraint(
+        pParse, OE_Abort, "indexed columns are not unique", P4_STATIC
+    );
+  }else{
+    addr2 = sqlite3VdbeCurrentAddr(v);
+  }
+  sqlite3VdbeAddOp2(v, OP_SorterData, iSorter, regRecord);
+  sqlite3VdbeAddOp3(v, OP_IdxInsert, iIdx, regRecord, 1);
+  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+#else
+  regIdxKey = sqlite3GenerateIndexKey(pParse, pIndex, iTab, regRecord, 1);
+  addr2 = addr1 + 1;
+  if( pIndex->onError!=OE_None ){
+    const int regRowid = regIdxKey + pIndex->nColumn;
+    const int j2 = sqlite3VdbeCurrentAddr(v) + 2;
+    void * const pRegKey = SQLITE_INT_TO_PTR(regIdxKey);
+
+    /* The registers accessed by the OP_IsUnique opcode were allocated
+    ** using sqlite3GetTempRange() inside of the sqlite3GenerateIndexKey()
+    ** call above. Just before that function was freed they were released
+    ** (made available to the compiler for reuse) using 
+    ** sqlite3ReleaseTempRange(). So in some ways having the OP_IsUnique
+    ** opcode use the values stored within seems dangerous. However, since
+    ** we can be sure that no other temp registers have been allocated
+    ** since sqlite3ReleaseTempRange() was called, it is safe to do so.
+    */
+    sqlite3VdbeAddOp4(v, OP_IsUnique, iIdx, j2, regRowid, pRegKey, P4_INT32);
+    sqlite3HaltConstraint(
+        pParse, OE_Abort, "indexed columns are not unique", P4_STATIC);
+  }
+  sqlite3VdbeAddOp3(v, OP_IdxInsert, iIdx, regRecord, 0);
+  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+#endif
+  sqlite3ReleaseTempReg(pParse, regRecord);
+  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2);
+  sqlite3VdbeJumpHere(v, addr1);
+
   sqlite3VdbeAddOp1(v, OP_Close, iTab);
   sqlite3VdbeAddOp1(v, OP_Close, iIdx);
+  sqlite3VdbeAddOp1(v, OP_Close, iSorter);
 }
 
 /*
@@ -63508,8 +82615,12 @@ static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
 ** pList is a list of columns to be indexed.  pList will be NULL if this
 ** is a primary key or unique-constraint on the most recent column added
 ** to the table currently under construction.  
+**
+** If the index is created successfully, return a pointer to the new Index
+** structure. This is used by sqlite3AddPrimaryKey() to mark the index
+** as the tables primary key (Index.autoIndex==2).
 */
-SQLITE_PRIVATE void sqlite3CreateIndex(
+SQLITE_PRIVATE Index *sqlite3CreateIndex(
   Parse *pParse,     /* All information about this parse */
   Token *pName1,     /* First part of index name. May be NULL */
   Token *pName2,     /* Second part of index name. May be NULL */
@@ -63521,6 +82632,7 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   int sortOrder,     /* Sort order of primary key when pList==NULL */
   int ifNotExist     /* Omit error if index already exists */
 ){
+  Index *pRet = 0;     /* Pointer to return */
   Table *pTab = 0;     /* Table to be indexed */
   Index *pIndex = 0;   /* The index to be created */
   char *zName = 0;     /* Name of the index */
@@ -63538,7 +82650,12 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   int nExtra = 0;
   char *zExtra;
 
-  if( pParse->nErr || db->mallocFailed || IN_DECLARE_VTAB ){
+  assert( pStart==0 || pEnd!=0 ); /* pEnd must be non-NULL if pStart is */
+  assert( pParse->nErr==0 );      /* Never called with prior errors */
+  if( db->mallocFailed || IN_DECLARE_VTAB ){
+    goto exit_create_index;
+  }
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
     goto exit_create_index;
   }
 
@@ -63554,15 +82671,16 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
     assert( pName1 && pName2 );
     iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
     if( iDb<0 ) goto exit_create_index;
+    assert( pName && pName->z );
 
 #ifndef SQLITE_OMIT_TEMPDB
-    /* If the index name was unqualified, check if the the table
+    /* If the index name was unqualified, check if the table
     ** is a temp table. If so, set the database to 1. Do not do this
     ** if initialising a database schema.
     */
     if( !db->init.busy ){
       pTab = sqlite3SrcListLookup(pParse, pTblName);
-      if( pName2 && pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
+      if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
         iDb = 1;
       }
     }
@@ -63581,14 +82699,17 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
     assert( db->aDb[iDb].pSchema==pTab->pSchema );
   }else{
     assert( pName==0 );
+    assert( pStart==0 );
     pTab = pParse->pNewTable;
     if( !pTab ) goto exit_create_index;
     iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
   }
   pDb = &db->aDb[iDb];
 
-  if( pTab==0 || pParse->nErr ) goto exit_create_index;
-  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
+  assert( pTab!=0 );
+  assert( pParse->nErr==0 );
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 
+       && memcmp(&pTab->zName[7],"altertab_",9)!=0 ){
     sqlite3ErrorMsg(pParse, "table %s may not be indexed", pTab->zName);
     goto exit_create_index;
   }
@@ -63620,13 +82741,12 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   */
   if( pName ){
     zName = sqlite3NameFromToken(db, pName);
-    if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto exit_create_index;
     if( zName==0 ) goto exit_create_index;
+    assert( pName->z!=0 );
     if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
       goto exit_create_index;
     }
     if( !db->init.busy ){
-      if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto exit_create_index;
       if( sqlite3FindTable(db, zName, 0)!=0 ){
         sqlite3ErrorMsg(pParse, "there is already a table named %s", zName);
         goto exit_create_index;
@@ -63635,6 +82755,9 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
     if( sqlite3FindIndex(db, zName, pDb->zName)!=0 ){
       if( !ifNotExist ){
         sqlite3ErrorMsg(pParse, "index %s already exists", zName);
+      }else{
+        assert( !db->init.busy );
+        sqlite3CodeVerifySchema(pParse, iDb);
       }
       goto exit_create_index;
     }
@@ -63669,10 +82792,11 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   ** So create a fake list to simulate this.
   */
   if( pList==0 ){
-    nullId.z = (u8*)pTab->aCol[pTab->nCol-1].zName;
+    nullId.z = pTab->aCol[pTab->nCol-1].zName;
     nullId.n = sqlite3Strlen30((char*)nullId.z);
-    pList = sqlite3ExprListAppend(pParse, 0, 0, &nullId);
+    pList = sqlite3ExprListAppend(pParse, 0, 0);
     if( pList==0 ) goto exit_create_index;
+    sqlite3ExprListSetName(pParse, pList, &nullId, 0);
     pList->a[0].sortOrder = (u8)sortOrder;
   }
 
@@ -63680,10 +82804,14 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   ** specified collation sequence names.
   */
   for(i=0; i<pList->nExpr; i++){
-    Expr *pExpr;
-    CollSeq *pColl;
-    if( (pExpr = pList->a[i].pExpr)!=0 && (pColl = pExpr->pColl)!=0 ){
-      nExtra += (1 + sqlite3Strlen30(pColl->zName));
+    Expr *pExpr = pList->a[i].pExpr;
+    if( pExpr ){
+      CollSeq *pColl = pExpr->pColl;
+      /* Either pColl!=0 or there was an OOM failure.  But if an OOM
+      ** failure we have quit before reaching this point. */
+      if( ALWAYS(pColl) ){
+        nExtra += (1 + sqlite3Strlen30(pColl->zName));
+      }
     }
   }
 
@@ -63693,21 +82821,25 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   nName = sqlite3Strlen30(zName);
   nCol = pList->nExpr;
   pIndex = sqlite3DbMallocZero(db, 
-      sizeof(Index) +              /* Index structure  */
-      sizeof(int)*nCol +           /* Index.aiColumn   */
-      sizeof(int)*(nCol+1) +       /* Index.aiRowEst   */
-      sizeof(char *)*nCol +        /* Index.azColl     */
-      sizeof(u8)*nCol +            /* Index.aSortOrder */
-      nName + 1 +                  /* Index.zName      */
-      nExtra                       /* Collation sequence names */
+      ROUND8(sizeof(Index)) +              /* Index structure  */
+      ROUND8(sizeof(tRowcnt)*(nCol+1)) +   /* Index.aiRowEst   */
+      sizeof(char *)*nCol +                /* Index.azColl     */
+      sizeof(int)*nCol +                   /* Index.aiColumn   */
+      sizeof(u8)*nCol +                    /* Index.aSortOrder */
+      nName + 1 +                          /* Index.zName      */
+      nExtra                               /* Collation sequence names */
   );
   if( db->mallocFailed ){
     goto exit_create_index;
   }
-  pIndex->azColl = (char**)(&pIndex[1]);
+  zExtra = (char*)pIndex;
+  pIndex->aiRowEst = (tRowcnt*)&zExtra[ROUND8(sizeof(Index))];
+  pIndex->azColl = (char**)
+     ((char*)pIndex->aiRowEst + ROUND8(sizeof(tRowcnt)*nCol+1));
+  assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowEst) );
+  assert( EIGHT_BYTE_ALIGNMENT(pIndex->azColl) );
   pIndex->aiColumn = (int *)(&pIndex->azColl[nCol]);
-  pIndex->aiRowEst = (unsigned *)(&pIndex->aiColumn[nCol]);
-  pIndex->aSortOrder = (u8 *)(&pIndex->aiRowEst[nCol+1]);
+  pIndex->aSortOrder = (u8 *)(&pIndex->aiColumn[nCol]);
   pIndex->zName = (char *)(&pIndex->aSortOrder[nCol]);
   zExtra = (char *)(&pIndex->zName[nName+1]);
   memcpy(pIndex->zName, zName, nName+1);
@@ -63716,6 +82848,7 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   pIndex->onError = (u8)onError;
   pIndex->autoIndex = (u8)(pName==0);
   pIndex->pSchema = db->aDb[iDb].pSchema;
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
 
   /* Check to see if we should honor DESC requests on index columns
   */
@@ -63728,6 +82861,12 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   /* Scan the names of the columns of the table to be indexed and
   ** load the column indices into the Index structure.  Report an error
   ** if any column is not found.
+  **
+  ** TODO:  Add a test to make sure that the same column is not named
+  ** more than once within the same index.  Only the first instance of
+  ** the column will ever be used by the optimizer.  Note that using the
+  ** same column more than once cannot be an error because that would 
+  ** break backwards compatibility - it needs to be a warning.
   */
   for(i=0, pListItem=pList->a; i<pList->nExpr; i++, pListItem++){
     const char *zColName = pListItem->zName;
@@ -63741,27 +82880,31 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
     if( j>=pTab->nCol ){
       sqlite3ErrorMsg(pParse, "table %s has no column named %s",
         pTab->zName, zColName);
+      pParse->checkSchema = 1;
       goto exit_create_index;
     }
-    /* TODO:  Add a test to make sure that the same column is not named
-    ** more than once within the same index.  Only the first instance of
-    ** the column will ever be used by the optimizer.  Note that using the
-    ** same column more than once cannot be an error because that would 
-    ** break backwards compatibility - it needs to be a warning.
-    */
     pIndex->aiColumn[i] = j;
-    if( pListItem->pExpr && pListItem->pExpr->pColl ){
-      assert( pListItem->pExpr->pColl );
+    /* Justification of the ALWAYS(pListItem->pExpr->pColl):  Because of
+    ** the way the "idxlist" non-terminal is constructed by the parser,
+    ** if pListItem->pExpr is not null then either pListItem->pExpr->pColl
+    ** must exist or else there must have been an OOM error.  But if there
+    ** was an OOM error, we would never reach this point. */
+    if( pListItem->pExpr && ALWAYS(pListItem->pExpr->pColl) ){
+      int nColl;
+      zColl = pListItem->pExpr->pColl->zName;
+      nColl = sqlite3Strlen30(zColl) + 1;
+      assert( nExtra>=nColl );
+      memcpy(zExtra, zColl, nColl);
       zColl = zExtra;
-      sqlite3_snprintf(nExtra, zExtra, "%s", pListItem->pExpr->pColl->zName);
-      zExtra += (sqlite3Strlen30(zColl) + 1);
+      zExtra += nColl;
+      nExtra -= nColl;
     }else{
       zColl = pTab->aCol[j].zColl;
       if( !zColl ){
-        zColl = db->pDfltColl->zName;
+        zColl = "BINARY";
       }
     }
-    if( !db->init.busy && !sqlite3LocateCollSeq(pParse, zColl, -1) ){
+    if( !db->init.busy && !sqlite3LocateCollSeq(pParse, zColl) ){
       goto exit_create_index;
     }
     pIndex->azColl[i] = zColl;
@@ -63783,6 +82926,14 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
     ** so, don't bother creating this one. This only applies to
     ** automatically created indices. Users can do as they wish with
     ** explicit indices.
+    **
+    ** Two UNIQUE or PRIMARY KEY constraints are considered equivalent
+    ** (and thus suppressing the second one) even if they have different
+    ** sort orders.
+    **
+    ** If there are different collating sequences or if the columns of
+    ** the constraint occur in different orders, then the constraints are
+    ** considered distinct and both result in separate indices.
     */
     Index *pIdx;
     for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
@@ -63793,10 +82944,11 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
 
       if( pIdx->nColumn!=pIndex->nColumn ) continue;
       for(k=0; k<pIdx->nColumn; k++){
-        const char *z1 = pIdx->azColl[k];
-        const char *z2 = pIndex->azColl[k];
+        const char *z1;
+        const char *z2;
         if( pIdx->aiColumn[k]!=pIndex->aiColumn[k] ) break;
-        if( pIdx->aSortOrder[k]!=pIndex->aSortOrder[k] ) break;
+        z1 = pIdx->azColl[k];
+        z2 = pIndex->azColl[k];
         if( z1!=z2 && sqlite3StrICmp(z1, z2) ) break;
       }
       if( k==pIdx->nColumn ){
@@ -63826,8 +82978,9 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   */
   if( db->init.busy ){
     Index *p;
+    assert( sqlite3SchemaMutexHeld(db, 0, pIndex->pSchema) );
     p = sqlite3HashInsert(&pIndex->pSchema->idxHash, 
-                          pIndex->zName, sqlite3Strlen30(pIndex->zName)+1,
+                          pIndex->zName, sqlite3Strlen30(pIndex->zName),
                           pIndex);
     if( p ){
       assert( p==pIndex );  /* Malloc must have failed */
@@ -63855,7 +83008,7 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
   ** has just been created, it contains no data and the index initialization
   ** step can be skipped.
   */
-  else if( db->init.busy==0 ){
+  else{ /* if( db->init.busy==0 ) */
     Vdbe *v;
     char *zStmt;
     int iMem = ++pParse->nMem;
@@ -63872,11 +83025,12 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
     /* Gather the complete text of the CREATE INDEX statement into
     ** the zStmt variable
     */
-    if( pStart && pEnd ){
+    if( pStart ){
+      assert( pEnd!=0 );
       /* A named index with an explicit CREATE INDEX statement */
       zStmt = sqlite3MPrintf(db, "CREATE%s INDEX %.*s",
         onError==OE_None ? "" : " UNIQUE",
-        pEnd->z - pName->z + 1,
+        (int)(pEnd->z - pName->z) + 1,
         pName->z);
     }else{
       /* An automatic index created by a PRIMARY KEY or UNIQUE constraint */
@@ -63902,16 +83056,17 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
     if( pTblName ){
       sqlite3RefillIndex(pParse, pIndex, iMem);
       sqlite3ChangeCookie(pParse, iDb);
-      sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0,
-         sqlite3MPrintf(db, "name='%q'", pIndex->zName), P4_DYNAMIC);
+      sqlite3VdbeAddParseSchemaOp(v, iDb,
+         sqlite3MPrintf(db, "name='%q' AND type='index'", pIndex->zName));
       sqlite3VdbeAddOp1(v, OP_Expire, 0);
     }
   }
 
   /* When adding an index to the list of indices for a table, make
   ** sure all indices labeled OE_Replace come after all those labeled
-  ** OE_Ignore.  This is necessary for the correct operation of UPDATE
-  ** and INSERT.
+  ** OE_Ignore.  This is necessary for the correct constraint check
+  ** processing (in sqlite3GenerateConstraintChecks()) as part of
+  ** UPDATE and INSERT statements.  
   */
   if( db->init.busy || pTblName==0 ){
     if( onError!=OE_Replace || pTab->pIndex==0
@@ -63926,40 +83081,20 @@ SQLITE_PRIVATE void sqlite3CreateIndex(
       pIndex->pNext = pOther->pNext;
       pOther->pNext = pIndex;
     }
+    pRet = pIndex;
     pIndex = 0;
   }
 
   /* Clean up before exiting */
 exit_create_index:
   if( pIndex ){
-    freeIndex(pIndex);
+    sqlite3DbFree(db, pIndex->zColAff);
+    sqlite3DbFree(db, pIndex);
   }
   sqlite3ExprListDelete(db, pList);
   sqlite3SrcListDelete(db, pTblName);
   sqlite3DbFree(db, zName);
-  return;
-}
-
-/*
-** Generate code to make sure the file format number is at least minFormat.
-** The generated code will increase the file format number if necessary.
-*/
-SQLITE_PRIVATE void sqlite3MinimumFileFormat(Parse *pParse, int iDb, int minFormat){
-  Vdbe *v;
-  v = sqlite3GetVdbe(pParse);
-  if( v ){
-    int r1 = sqlite3GetTempReg(pParse);
-    int r2 = sqlite3GetTempReg(pParse);
-    int j1;
-    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, 1);
-    sqlite3VdbeUsesBtree(v, iDb);
-    sqlite3VdbeAddOp2(v, OP_Integer, minFormat, r2);
-    j1 = sqlite3VdbeAddOp3(v, OP_Ge, r2, 0, r1);
-    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 1, r2);
-    sqlite3VdbeJumpHere(v, j1);
-    sqlite3ReleaseTempReg(pParse, r1);
-    sqlite3ReleaseTempReg(pParse, r2);
-  }
+  return pRet;
 }
 
 /*
@@ -63981,16 +83116,16 @@ SQLITE_PRIVATE void sqlite3MinimumFileFormat(Parse *pParse, int iDb, int minForm
 ** are based on typical values found in actual indices.
 */
 SQLITE_PRIVATE void sqlite3DefaultRowEst(Index *pIdx){
-  unsigned *a = pIdx->aiRowEst;
+  tRowcnt *a = pIdx->aiRowEst;
   int i;
+  tRowcnt n;
   assert( a!=0 );
-  a[0] = 1000000;
-  for(i=pIdx->nColumn; i>=5; i--){
-    a[i] = 5;
-  }
-  while( i>=1 ){
-    a[i] = 11 - i;
-    i--;
+  a[0] = pIdx->pTable->nRowEst;
+  if( a[0]<10 ) a[0] = 10;
+  n = 10;
+  for(i=1; i<=pIdx->nColumn; i++){
+    a[i] = n;
+    if( n>5 ) n--;
   }
   if( pIdx->onError!=OE_None ){
     a[pIdx->nColumn] = 1;
@@ -64007,7 +83142,8 @@ SQLITE_PRIVATE void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists
   sqlite3 *db = pParse->db;
   int iDb;
 
-  if( pParse->nErr || db->mallocFailed ){
+  assert( pParse->nErr==0 );   /* Never called with prior errors */
+  if( db->mallocFailed ){
     goto exit_drop_index;
   }
   assert( pName->nSrc==1 );
@@ -64018,6 +83154,8 @@ SQLITE_PRIVATE void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists
   if( pIndex==0 ){
     if( !ifExists ){
       sqlite3ErrorMsg(pParse, "no such index: %S", pName, 0);
+    }else{
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
     }
     pParse->checkSchema = 1;
     goto exit_drop_index;
@@ -64049,16 +83187,10 @@ SQLITE_PRIVATE void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists
   if( v ){
     sqlite3BeginWriteOperation(pParse, 1, iDb);
     sqlite3NestedParse(pParse,
-       "DELETE FROM %Q.%s WHERE name=%Q",
-       db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
-       pIndex->zName
+       "DELETE FROM %Q.%s WHERE name=%Q AND type='index'",
+       db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pIndex->zName
     );
-    if( sqlite3FindTable(db, "sqlite_stat1", db->aDb[iDb].zName) ){
-      sqlite3NestedParse(pParse,
-        "DELETE FROM %Q.sqlite_stat1 WHERE idx=%Q",
-        db->aDb[iDb].zName, pIndex->zName
-      );
-    }
+    sqlite3ClearStatTables(pParse, iDb, "idx", pIndex->zName);
     sqlite3ChangeCookie(pParse, iDb);
     destroyRootPage(pParse, pIndex->tnum, iDb);
     sqlite3VdbeAddOp4(v, OP_DropIndex, iDb, 0, 0, pIndex->zName, 0);
@@ -64069,45 +83201,43 @@ exit_drop_index:
 }
 
 /*
-** pArray is a pointer to an array of objects.  Each object in the
-** array is szEntry bytes in size.  This routine allocates a new
-** object on the end of the array.
+** pArray is a pointer to an array of objects. Each object in the
+** array is szEntry bytes in size. This routine uses sqlite3DbRealloc()
+** to extend the array so that there is space for a new object at the end.
 **
-** *pnEntry is the number of entries already in use.  *pnAlloc is
-** the previously allocated size of the array.  initSize is the
-** suggested initial array size allocation.
+** When this function is called, *pnEntry contains the current size of
+** the array (in entries - so the allocation is ((*pnEntry) * szEntry) bytes
+** in total).
 **
-** The index of the new entry is returned in *pIdx.
+** If the realloc() is successful (i.e. if no OOM condition occurs), the
+** space allocated for the new object is zeroed, *pnEntry updated to
+** reflect the new size of the array and a pointer to the new allocation
+** returned. *pIdx is set to the index of the new array entry in this case.
 **
-** This routine returns a pointer to the array of objects.  This
-** might be the same as the pArray parameter or it might be a different
-** pointer if the array was resized.
+** Otherwise, if the realloc() fails, *pIdx is set to -1, *pnEntry remains
+** unchanged and a copy of pArray returned.
 */
 SQLITE_PRIVATE void *sqlite3ArrayAllocate(
   sqlite3 *db,      /* Connection to notify of malloc failures */
   void *pArray,     /* Array of objects.  Might be reallocated */
   int szEntry,      /* Size of each object in the array */
-  int initSize,     /* Suggested initial allocation, in elements */
   int *pnEntry,     /* Number of objects currently in use */
-  int *pnAlloc,     /* Current size of the allocation, in elements */
   int *pIdx         /* Write the index of a new slot here */
 ){
   char *z;
-  if( *pnEntry >= *pnAlloc ){
-    void *pNew;
-    int newSize;
-    newSize = (*pnAlloc)*2 + initSize;
-    pNew = sqlite3DbRealloc(db, pArray, newSize*szEntry);
+  int n = *pnEntry;
+  if( (n & (n-1))==0 ){
+    int sz = (n==0) ? 1 : 2*n;
+    void *pNew = sqlite3DbRealloc(db, pArray, sz*szEntry);
     if( pNew==0 ){
       *pIdx = -1;
       return pArray;
     }
-    *pnAlloc = sqlite3DbMallocSize(db, pNew)/szEntry;
     pArray = pNew;
   }
   z = (char*)pArray;
-  memset(&z[*pnEntry * szEntry], 0, szEntry);
-  *pIdx = *pnEntry;
+  memset(&z[n * szEntry], 0, szEntry);
+  *pIdx = n;
   ++*pnEntry;
   return pArray;
 }
@@ -64123,15 +83253,12 @@ SQLITE_PRIVATE IdList *sqlite3IdListAppend(sqlite3 *db, IdList *pList, Token *pT
   if( pList==0 ){
     pList = sqlite3DbMallocZero(db, sizeof(IdList) );
     if( pList==0 ) return 0;
-    pList->nAlloc = 0;
   }
   pList->a = sqlite3ArrayAllocate(
       db,
       pList->a,
       sizeof(pList->a[0]),
-      5,
       &pList->nId,
-      &pList->nAlloc,
       &i
   );
   if( i<0 ){
@@ -64198,10 +83325,8 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(
   /* Sanity checking on calling parameters */
   assert( iStart>=0 );
   assert( nExtra>=1 );
-  if( pSrc==0 || iStart>pSrc->nSrc ){
-    assert( db->mallocFailed );
-    return pSrc;
-  }
+  assert( pSrc!=0 );
+  assert( iStart<=pSrc->nSrc );
 
   /* Allocate additional space if needed */
   if( pSrc->nSrc+nExtra>pSrc->nAlloc ){
@@ -64239,7 +83364,7 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(
 
 /*
 ** Append a new table name to the given SrcList.  Create a new SrcList if
-** need be.  A new entry is created in the SrcList even if pToken is NULL.
+** need be.  A new entry is created in the SrcList even if pTable is NULL.
 **
 ** A SrcList is returned, or NULL if there is an OOM error.  The returned
 ** SrcList might be the same as the SrcList that was input or it might be
@@ -64263,7 +83388,13 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(
 **
 **         sqlite3SrcListAppend(D,A,B,C);
 **
-** Then C is the table name and B is the database name.
+** Then C is the table name and B is the database name.  If C is defined
+** then so is B.  In other words, we never have a case where:
+**
+**         sqlite3SrcListAppend(D,A,0,C);
+**
+** Both pTable and pDatabase are assumed to be quoted.  They are dequoted
+** before being added to the SrcList.
 */
 SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(
   sqlite3 *db,        /* Connection to notify of malloc failures */
@@ -64272,6 +83403,7 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(
   Token *pDatabase    /* Database of the table */
 ){
   struct SrcList_item *pItem;
+  assert( pDatabase==0 || pTable!=0 );  /* Cannot have C without B */
   if( pList==0 ){
     pList = sqlite3DbMallocZero(db, sizeof(SrcList) );
     if( pList==0 ) return 0;
@@ -64286,7 +83418,7 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(
   if( pDatabase && pDatabase->z==0 ){
     pDatabase = 0;
   }
-  if( pDatabase && pTable ){
+  if( pDatabase ){
     Token *pTemp = pDatabase;
     pDatabase = pTable;
     pTable = pTemp;
@@ -64326,7 +83458,7 @@ SQLITE_PRIVATE void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
     sqlite3DbFree(db, pItem->zName);
     sqlite3DbFree(db, pItem->zAlias);
     sqlite3DbFree(db, pItem->zIndex);
-    sqlite3DeleteTable(pItem->pTab);
+    sqlite3DeleteTable(db, pItem->pTab);
     sqlite3SelectDelete(db, pItem->pSelect);
     sqlite3ExprDelete(db, pItem->pOn);
     sqlite3IdListDelete(db, pItem->pUsing);
@@ -64362,21 +83494,32 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(
 ){
   struct SrcList_item *pItem;
   sqlite3 *db = pParse->db;
+  if( !p && (pOn || pUsing) ){
+    sqlite3ErrorMsg(pParse, "a JOIN clause is required before %s", 
+      (pOn ? "ON" : "USING")
+    );
+    goto append_from_error;
+  }
   p = sqlite3SrcListAppend(db, p, pTable, pDatabase);
-  if( p==0 || p->nSrc==0 ){
-    sqlite3ExprDelete(db, pOn);
-    sqlite3IdListDelete(db, pUsing);
-    sqlite3SelectDelete(db, pSubquery);
-    return p;
+  if( p==0 || NEVER(p->nSrc==0) ){
+    goto append_from_error;
   }
   pItem = &p->a[p->nSrc-1];
-  if( pAlias && pAlias->n ){
+  assert( pAlias!=0 );
+  if( pAlias->n ){
     pItem->zAlias = sqlite3NameFromToken(db, pAlias);
   }
   pItem->pSelect = pSubquery;
   pItem->pOn = pOn;
   pItem->pUsing = pUsing;
   return p;
+
+ append_from_error:
+  assert( p==0 );
+  sqlite3ExprDelete(db, pOn);
+  sqlite3IdListDelete(db, pUsing);
+  sqlite3SelectDelete(db, pSubquery);
+  return 0;
 }
 
 /*
@@ -64384,7 +83527,8 @@ SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(
 ** element of the source-list passed as the second argument.
 */
 SQLITE_PRIVATE void sqlite3SrcListIndexedBy(Parse *pParse, SrcList *p, Token *pIndexedBy){
-  if( pIndexedBy && p && p->nSrc>0 ){
+  assert( pIndexedBy!=0 );
+  if( p && ALWAYS(p->nSrc>0) ){
     struct SrcList_item *pItem = &p->a[p->nSrc-1];
     assert( pItem->notIndexed==0 && pItem->zIndex==0 );
     if( pIndexedBy->n==1 && !pIndexedBy->z ){
@@ -64413,8 +83557,9 @@ SQLITE_PRIVATE void sqlite3SrcListIndexedBy(Parse *pParse, SrcList *p, Token *pI
 ** operator with A.  This routine shifts that operator over to B.
 */
 SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(SrcList *p){
-  if( p && p->a ){
+  if( p ){
     int i;
+    assert( p->a || p->nSrc==0 );
     for(i=p->nSrc-1; i>0; i--){
       p->a[i].jointype = p->a[i-1].jointype;
     }
@@ -64430,10 +83575,13 @@ SQLITE_PRIVATE void sqlite3BeginTransaction(Parse *pParse, int type){
   Vdbe *v;
   int i;
 
-  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
-  if( pParse->nErr || db->mallocFailed ) return;
-  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ) return;
-
+  assert( pParse!=0 );
+  db = pParse->db;
+  assert( db!=0 );
+/*  if( db->aDb[0].pBt==0 ) return; */
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ){
+    return;
+  }
   v = sqlite3GetVdbe(pParse);
   if( !v ) return;
   if( type!=TK_DEFERRED ){
@@ -64449,13 +83597,13 @@ SQLITE_PRIVATE void sqlite3BeginTransaction(Parse *pParse, int type){
 ** Commit a transaction
 */
 SQLITE_PRIVATE void sqlite3CommitTransaction(Parse *pParse){
-  sqlite3 *db;
   Vdbe *v;
 
-  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
-  if( pParse->nErr || db->mallocFailed ) return;
-  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "COMMIT", 0, 0) ) return;
-
+  assert( pParse!=0 );
+  assert( pParse->db!=0 );
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "COMMIT", 0, 0) ){
+    return;
+  }
   v = sqlite3GetVdbe(pParse);
   if( v ){
     sqlite3VdbeAddOp2(v, OP_AutoCommit, 1, 0);
@@ -64466,13 +83614,13 @@ SQLITE_PRIVATE void sqlite3CommitTransaction(Parse *pParse){
 ** Rollback a transaction
 */
 SQLITE_PRIVATE void sqlite3RollbackTransaction(Parse *pParse){
-  sqlite3 *db;
   Vdbe *v;
 
-  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
-  if( pParse->nErr || db->mallocFailed ) return;
-  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "ROLLBACK", 0, 0) ) return;
-
+  assert( pParse!=0 );
+  assert( pParse->db!=0 );
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "ROLLBACK", 0, 0) ){
+    return;
+  }
   v = sqlite3GetVdbe(pParse);
   if( v ){
     sqlite3VdbeAddOp2(v, OP_AutoCommit, 1, 1);
@@ -64488,7 +83636,7 @@ SQLITE_PRIVATE void sqlite3Savepoint(Parse *pParse, int op, Token *pName){
   if( zName ){
     Vdbe *v = sqlite3GetVdbe(pParse);
 #ifndef SQLITE_OMIT_AUTHORIZATION
-    static const char *az[] = { "BEGIN", "RELEASE", "ROLLBACK" };
+    static const char * const az[] = { "BEGIN", "RELEASE", "ROLLBACK" };
     assert( !SAVEPOINT_BEGIN && SAVEPOINT_RELEASE==1 && SAVEPOINT_ROLLBACK==2 );
 #endif
     if( !v || sqlite3AuthCheck(pParse, SQLITE_SAVEPOINT, az[op], zName, 0) ){
@@ -64507,6 +83655,7 @@ SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
   sqlite3 *db = pParse->db;
   if( db->aDb[1].pBt==0 && !pParse->explain ){
     int rc;
+    Btree *pBt;
     static const int flags = 
           SQLITE_OPEN_READWRITE |
           SQLITE_OPEN_CREATE |
@@ -64514,18 +83663,19 @@ SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
           SQLITE_OPEN_DELETEONCLOSE |
           SQLITE_OPEN_TEMP_DB;
 
-    rc = sqlite3BtreeFactory(db, 0, 0, SQLITE_DEFAULT_CACHE_SIZE, flags,
-                                 &db->aDb[1].pBt);
+    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pBt, 0, flags);
     if( rc!=SQLITE_OK ){
       sqlite3ErrorMsg(pParse, "unable to open a temporary database "
         "file for storing temporary tables");
       pParse->rc = rc;
       return 1;
     }
-    assert( (db->flags & SQLITE_InTrans)==0 || db->autoCommit );
+    db->aDb[1].pBt = pBt;
     assert( db->aDb[1].pSchema );
-    sqlite3PagerJournalMode(sqlite3BtreePager(db->aDb[1].pBt),
-                            db->dfltJournalMode);
+    if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, -1, 0) ){
+      db->mallocFailed = 1;
+      return 1;
+    }
   }
   return 0;
 }
@@ -64553,31 +83703,47 @@ SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
 ** early in the code, before we know if any database tables will be used.
 */
 SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
-  sqlite3 *db;
-  Vdbe *v;
-  int mask;
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
 
-  v = sqlite3GetVdbe(pParse);
-  if( v==0 ) return;  /* This only happens if there was a prior error */
-  db = pParse->db;
-  if( pParse->cookieGoto==0 ){
-    pParse->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
+  if( pToplevel->cookieGoto==0 ){
+    Vdbe *v = sqlite3GetVdbe(pToplevel);
+    if( v==0 ) return;  /* This only happens if there was a prior error */
+    pToplevel->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
   }
   if( iDb>=0 ){
+    sqlite3 *db = pToplevel->db;
+    yDbMask mask;
+
     assert( iDb<db->nDb );
     assert( db->aDb[iDb].pBt!=0 || iDb==1 );
     assert( iDb<SQLITE_MAX_ATTACHED+2 );
-    mask = 1<<iDb;
-    if( (pParse->cookieMask & mask)==0 ){
-      pParse->cookieMask |= mask;
-      pParse->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    mask = ((yDbMask)1)<<iDb;
+    if( (pToplevel->cookieMask & mask)==0 ){
+      pToplevel->cookieMask |= mask;
+      pToplevel->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
       if( !OMIT_TEMPDB && iDb==1 ){
-        sqlite3OpenTempDatabase(pParse);
+        sqlite3OpenTempDatabase(pToplevel);
       }
     }
   }
 }
 
+/*
+** If argument zDb is NULL, then call sqlite3CodeVerifySchema() for each 
+** attached database. Otherwise, invoke it for the database named zDb only.
+*/
+SQLITE_PRIVATE void sqlite3CodeVerifyNamedSchema(Parse *pParse, const char *zDb){
+  sqlite3 *db = pParse->db;
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Db *pDb = &db->aDb[i];
+    if( pDb->pBt && (!zDb || 0==sqlite3StrICmp(zDb, pDb->zName)) ){
+      sqlite3CodeVerifySchema(pParse, i);
+    }
+  }
+}
+
 /*
 ** Generate VDBE code that prepares for doing an operation that
 ** might change the database.
@@ -64590,23 +83756,58 @@ SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
 ** rollback the whole transaction.  For operations where all constraints
 ** can be checked before any changes are made to the database, it is never
 ** necessary to undo a write and the checkpoint should not be set.
-**
-** Only database iDb and the temp database are made writable by this call.
-** If iDb==0, then the main and temp databases are made writable.   If
-** iDb==1 then only the temp database is made writable.  If iDb>1 then the
-** specified auxiliary database and the temp database are made writable.
 */
 SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse *pParse, int setStatement, int iDb){
-  Vdbe *v = sqlite3GetVdbe(pParse);
-  if( v==0 ) return;
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
   sqlite3CodeVerifySchema(pParse, iDb);
-  pParse->writeMask |= 1<<iDb;
-  if( setStatement && pParse->nested==0 ){
-    sqlite3VdbeAddOp1(v, OP_Statement, iDb);
-  }
-  if( (OMIT_TEMPDB || iDb!=1) && pParse->db->aDb[1].pBt!=0 ){
-    sqlite3BeginWriteOperation(pParse, setStatement, 1);
+  pToplevel->writeMask |= ((yDbMask)1)<<iDb;
+  pToplevel->isMultiWrite |= setStatement;
+}
+
+/*
+** Indicate that the statement currently under construction might write
+** more than one entry (example: deleting one row then inserting another,
+** inserting multiple rows in a table, or inserting a row and index entries.)
+** If an abort occurs after some of these writes have completed, then it will
+** be necessary to undo the completed writes.
+*/
+SQLITE_PRIVATE void sqlite3MultiWrite(Parse *pParse){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  pToplevel->isMultiWrite = 1;
+}
+
+/* 
+** The code generator calls this routine if is discovers that it is
+** possible to abort a statement prior to completion.  In order to 
+** perform this abort without corrupting the database, we need to make
+** sure that the statement is protected by a statement transaction.
+**
+** Technically, we only need to set the mayAbort flag if the
+** isMultiWrite flag was previously set.  There is a time dependency
+** such that the abort must occur after the multiwrite.  This makes
+** some statements involving the REPLACE conflict resolution algorithm
+** go a little faster.  But taking advantage of this time dependency
+** makes it more difficult to prove that the code is correct (in 
+** particular, it prevents us from writing an effective
+** implementation of sqlite3AssertMayAbort()) and so we have chosen
+** to take the safe route and skip the optimization.
+*/
+SQLITE_PRIVATE void sqlite3MayAbort(Parse *pParse){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  pToplevel->mayAbort = 1;
+}
+
+/*
+** Code an OP_Halt that causes the vdbe to return an SQLITE_CONSTRAINT
+** error. The onError parameter determines which (if any) of the statement
+** and/or current transaction is rolled back.
+*/
+SQLITE_PRIVATE void sqlite3HaltConstraint(Parse *pParse, int onError, char *p4, int p4type){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( onError==OE_Abort ){
+    sqlite3MayAbort(pParse);
   }
+  sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0, p4, p4type);
 }
 
 /*
@@ -64616,9 +83817,11 @@ SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse *pParse, int setStatement,
 #ifndef SQLITE_OMIT_REINDEX
 static int collationMatch(const char *zColl, Index *pIndex){
   int i;
+  assert( zColl!=0 );
   for(i=0; i<pIndex->nColumn; i++){
     const char *z = pIndex->azColl[i];
-    if( z==zColl || (z && zColl && 0==sqlite3StrICmp(z, zColl)) ){
+    assert( z!=0 );
+    if( 0==sqlite3StrICmp(z, zColl) ){
       return 1;
     }
   }
@@ -64657,6 +83860,7 @@ static void reindexDatabases(Parse *pParse, char const *zColl){
   HashElem *k;                /* For looping over tables in pDb */
   Table *pTab;                /* A table in the database */
 
+  assert( sqlite3BtreeHoldsAllMutexes(db) );  /* Needed for schema access */
   for(iDb=0, pDb=db->aDb; iDb<db->nDb; iDb++, pDb++){
     assert( pDb!=0 );
     for(k=sqliteHashFirst(&pDb->pSchema->tblHash);  k; k=sqliteHashNext(k)){
@@ -64697,20 +83901,18 @@ SQLITE_PRIVATE void sqlite3Reindex(Parse *pParse, Token *pName1, Token *pName2){
     return;
   }
 
-  if( pName1==0 || pName1->z==0 ){
+  if( pName1==0 ){
     reindexDatabases(pParse, 0);
     return;
-  }else if( pName2==0 || pName2->z==0 ){
+  }else if( NEVER(pName2==0) || pName2->z==0 ){
     char *zColl;
     assert( pName1->z );
     zColl = sqlite3NameFromToken(pParse->db, pName1);
     if( !zColl ) return;
-    pColl = sqlite3FindCollSeq(db, ENC(db), zColl, -1, 0);
+    pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
     if( pColl ){
-      if( zColl ){
-        reindexDatabases(pParse, zColl);
-        sqlite3DbFree(db, zColl);
-      }
+      reindexDatabases(pParse, zColl);
+      sqlite3DbFree(db, zColl);
       return;
     }
     sqlite3DbFree(db, zColl);
@@ -64761,7 +83963,7 @@ SQLITE_PRIVATE KeyInfo *sqlite3IndexKeyinfo(Parse *pParse, Index *pIdx){
     for(i=0; i<nCol; i++){
       char *zColl = pIdx->azColl[i];
       assert( zColl );
-      pKey->aColl[i] = sqlite3LocateCollSeq(pParse, zColl, -1);
+      pKey->aColl[i] = sqlite3LocateCollSeq(pParse, zColl);
       pKey->aSortOrder[i] = pIdx->aSortOrder[i];
     }
     pKey->nField = (u16)nCol;
@@ -64790,30 +83992,26 @@ SQLITE_PRIVATE KeyInfo *sqlite3IndexKeyinfo(Parse *pParse, Index *pIdx){
 **
 ** This file contains functions used to access the internal hash tables
 ** of user defined functions and collation sequences.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
 /*
 ** Invoke the 'collation needed' callback to request a collation sequence
-** in the database text encoding of name zName, length nName.
-** If the collation sequence
+** in the encoding enc of name zName, length nName.
 */
-static void callCollNeeded(sqlite3 *db, const char *zName, int nName){
+static void callCollNeeded(sqlite3 *db, int enc, const char *zName){
   assert( !db->xCollNeeded || !db->xCollNeeded16 );
-  if( nName<0 ) nName = sqlite3Strlen(db, zName);
   if( db->xCollNeeded ){
-    char *zExternal = sqlite3DbStrNDup(db, zName, nName);
+    char *zExternal = sqlite3DbStrDup(db, zName);
     if( !zExternal ) return;
-    db->xCollNeeded(db->pCollNeededArg, db, (int)ENC(db), zExternal);
+    db->xCollNeeded(db->pCollNeededArg, db, enc, zExternal);
     sqlite3DbFree(db, zExternal);
   }
 #ifndef SQLITE_OMIT_UTF16
   if( db->xCollNeeded16 ){
     char const *zExternal;
     sqlite3_value *pTmp = sqlite3ValueNew(db);
-    sqlite3ValueSetStr(pTmp, nName, zName, SQLITE_UTF8, SQLITE_STATIC);
+    sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC);
     zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
     if( zExternal ){
       db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal);
@@ -64833,11 +84031,10 @@ static void callCollNeeded(sqlite3 *db, const char *zName, int nName){
 static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
   CollSeq *pColl2;
   char *z = pColl->zName;
-  int n = sqlite3Strlen30(z);
   int i;
   static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
   for(i=0; i<3; i++){
-    pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, n, 0);
+    pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 0);
     if( pColl2->xCmp!=0 ){
       memcpy(pColl, pColl2, sizeof(CollSeq));
       pColl->xDel = 0;         /* Do not copy the destructor */
@@ -64850,8 +84047,7 @@ static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
 /*
 ** This function is responsible for invoking the collation factory callback
 ** or substituting a collation sequence of a different encoding when the
-** requested collation sequence is not available in the database native
-** encoding.
+** requested collation sequence is not available in the desired encoding.
 ** 
 ** If it is not NULL, then pColl must point to the database native encoding 
 ** collation sequence with name zName, length nName.
@@ -64859,25 +84055,27 @@ static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
 ** The return value is either the collation sequence to be used in database
 ** db for collation type name zName, length nName, or NULL, if no collation
 ** sequence can be found.
+**
+** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq()
 */
 SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(
-  sqlite3* db, 
-  CollSeq *pColl, 
-  const char *zName, 
-  int nName
+  sqlite3* db,          /* The database connection */
+  u8 enc,               /* The desired encoding for the collating sequence */
+  CollSeq *pColl,       /* Collating sequence with native encoding, or NULL */
+  const char *zName     /* Collating sequence name */
 ){
   CollSeq *p;
 
   p = pColl;
   if( !p ){
-    p = sqlite3FindCollSeq(db, ENC(db), zName, nName, 0);
+    p = sqlite3FindCollSeq(db, enc, zName, 0);
   }
   if( !p || !p->xCmp ){
     /* No collation sequence of this type for this encoding is registered.
     ** Call the collation factory to see if it can supply us with one.
     */
-    callCollNeeded(db, zName, nName);
-    p = sqlite3FindCollSeq(db, ENC(db), zName, nName, 0);
+    callCollNeeded(db, enc, zName);
+    p = sqlite3FindCollSeq(db, enc, zName, 0);
   }
   if( p && !p->xCmp && synthCollSeq(db, p) ){
     p = 0;
@@ -64900,11 +84098,10 @@ SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(
 SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
   if( pColl ){
     const char *zName = pColl->zName;
-    CollSeq *p = sqlite3GetCollSeq(pParse->db, pColl, zName, -1);
+    sqlite3 *db = pParse->db;
+    CollSeq *p = sqlite3GetCollSeq(db, ENC(db), pColl, zName);
     if( !p ){
-      if( pParse->nErr==0 ){
-        sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
-      }
+      sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
       pParse->nErr++;
       return SQLITE_ERROR;
     }
@@ -64929,13 +84126,12 @@ SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
 ** each collation sequence structure.
 */
 static CollSeq *findCollSeqEntry(
-  sqlite3 *db,
-  const char *zName,
-  int nName,
-  int create
+  sqlite3 *db,          /* Database connection */
+  const char *zName,    /* Name of the collating sequence */
+  int create            /* Create a new entry if true */
 ){
   CollSeq *pColl;
-  if( nName<0 ) nName = sqlite3Strlen(db, zName);
+  int nName = sqlite3Strlen30(zName);
   pColl = sqlite3HashFind(&db->aCollSeq, zName, nName);
 
   if( 0==pColl && create ){
@@ -64952,7 +84148,7 @@ static CollSeq *findCollSeqEntry(
       pColl[0].zName[nName] = 0;
       pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl);
 
-      /* If a malloc() failure occured in sqlite3HashInsert(), it will 
+      /* If a malloc() failure occurred in sqlite3HashInsert(), it will 
       ** return the pColl pointer to be deleted (because it wasn't added
       ** to the hash table).
       */
@@ -64979,17 +84175,18 @@ static CollSeq *findCollSeqEntry(
 ** this routine.  sqlite3LocateCollSeq() invokes the collation factory
 ** if necessary and generates an error message if the collating sequence
 ** cannot be found.
+**
+** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq()
 */
 SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(
   sqlite3 *db,
   u8 enc,
   const char *zName,
-  int nName,
   int create
 ){
   CollSeq *pColl;
   if( zName ){
-    pColl = findCollSeqEntry(db, zName, nName, create);
+    pColl = findCollSeqEntry(db, zName, create);
   }else{
     pColl = db->pDfltColl;
   }
@@ -65005,35 +84202,57 @@ SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(
 ** that uses encoding enc. The value returned indicates how well the
 ** request is matched. A higher value indicates a better match.
 **
-** The returned value is always between 1 and 6, as follows:
+** If nArg is -1 that means to only return a match (non-zero) if p->nArg
+** is also -1.  In other words, we are searching for a function that
+** takes a variable number of arguments.
 **
-** 1: A variable arguments function that prefers UTF-8 when a UTF-16
-**    encoding is requested, or vice versa.
-** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is
-**    requested, or vice versa.
-** 3: A variable arguments function using the same text encoding.
-** 4: A function with the exact number of arguments requested that
-**    prefers UTF-8 when a UTF-16 encoding is requested, or vice versa.
-** 5: A function with the exact number of arguments requested that
-**    prefers UTF-16LE when UTF-16BE is requested, or vice versa.
-** 6: An exact match.
+** If nArg is -2 that means that we are searching for any function 
+** regardless of the number of arguments it uses, so return a positive
+** match score for any
 **
+** The returned value is always between 0 and 6, as follows:
+**
+** 0: Not a match.
+** 1: UTF8/16 conversion required and function takes any number of arguments.
+** 2: UTF16 byte order change required and function takes any number of args.
+** 3: encoding matches and function takes any number of arguments
+** 4: UTF8/16 conversion required - argument count matches exactly
+** 5: UTF16 byte order conversion required - argument count matches exactly
+** 6: Perfect match:  encoding and argument count match exactly.
+**
+** If nArg==(-2) then any function with a non-null xStep or xFunc is
+** a perfect match and any function with both xStep and xFunc NULL is
+** a non-match.
 */
-static int matchQuality(FuncDef *p, int nArg, u8 enc){
-  int match = 0;
-  if( p->nArg==-1 || p->nArg==nArg || nArg==-1 ){
+#define FUNC_PERFECT_MATCH 6  /* The score for a perfect match */
+static int matchQuality(
+  FuncDef *p,     /* The function we are evaluating for match quality */
+  int nArg,       /* Desired number of arguments.  (-1)==any */
+  u8 enc          /* Desired text encoding */
+){
+  int match;
+
+  /* nArg of -2 is a special case */
+  if( nArg==(-2) ) return (p->xFunc==0 && p->xStep==0) ? 0 : FUNC_PERFECT_MATCH;
+
+  /* Wrong number of arguments means "no match" */
+  if( p->nArg!=nArg && p->nArg>=0 ) return 0;
+
+  /* Give a better score to a function with a specific number of arguments
+  ** than to function that accepts any number of arguments. */
+  if( p->nArg==nArg ){
+    match = 4;
+  }else{
     match = 1;
-    if( p->nArg==nArg || nArg==-1 ){
-      match = 4;
-    }
-    if( enc==p->iPrefEnc ){
-      match += 2;
-    }
-    else if( (enc==SQLITE_UTF16LE && p->iPrefEnc==SQLITE_UTF16BE) ||
-             (enc==SQLITE_UTF16BE && p->iPrefEnc==SQLITE_UTF16LE) ){
-      match += 1;
-    }
   }
+
+  /* Bonus points if the text encoding matches */
+  if( enc==p->iPrefEnc ){
+    match += 2;  /* Exact encoding match */
+  }else if( (enc & p->iPrefEnc & 2)!=0 ){
+    match += 1;  /* Both are UTF16, but with different byte orders */
+  }
+
   return match;
 }
 
@@ -65069,6 +84288,7 @@ SQLITE_PRIVATE void sqlite3FuncDefInsert(
   int h = (sqlite3UpperToLower[c1] + nName) % ArraySize(pHash->a);
   pOther = functionSearch(pHash, h, pDef->zName, nName);
   if( pOther ){
+    assert( pOther!=pDef && pOther->pNext!=pDef );
     pDef->pNext = pOther->pNext;
     pOther->pNext = pDef;
   }else{
@@ -65088,13 +84308,12 @@ SQLITE_PRIVATE void sqlite3FuncDefInsert(
 **
 ** If the createFlag argument is true, then a new (blank) FuncDef
 ** structure is created and liked into the "db" structure if a
-** no matching function previously existed.  When createFlag is true
-** and the nArg parameter is -1, then only a function that accepts
-** any number of arguments will be returned.
+** no matching function previously existed.
 **
-** If createFlag is false and nArg is -1, then the first valid
-** function found is returned.  A function is valid if either xFunc
-** or xStep is non-zero.
+** If nArg is -2, then the first valid function found is returned.  A
+** function is valid if either xFunc or xStep is non-zero.  The nArg==(-2)
+** case is used to see if zName is a valid function name for some number
+** of arguments.  If nArg is -2, then createFlag must be 0.
 **
 ** If createFlag is false, then a function with the required name and
 ** number of arguments may be returned even if the eTextRep flag does not
@@ -65106,16 +84325,16 @@ SQLITE_PRIVATE FuncDef *sqlite3FindFunction(
   int nName,         /* Number of characters in the name */
   int nArg,          /* Number of arguments.  -1 means any number */
   u8 enc,            /* Preferred text encoding */
-  int createFlag     /* Create new entry if true and does not otherwise exist */
+  u8 createFlag      /* Create new entry if true and does not otherwise exist */
 ){
   FuncDef *p;         /* Iterator variable */
   FuncDef *pBest = 0; /* Best match found so far */
   int bestScore = 0;  /* Score of best match */
   int h;              /* Hash value */
 
-
+  assert( nArg>=(-2) );
+  assert( nArg>=(-1) || createFlag==0 );
   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
-  if( nArg<-1 ) nArg = -1;
   h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % ArraySize(db->aFunc.a);
 
   /* First search for a match amongst the application-defined functions.
@@ -65132,14 +84351,19 @@ SQLITE_PRIVATE FuncDef *sqlite3FindFunction(
 
   /* If no match is found, search the built-in functions.
   **
+  ** If the SQLITE_PreferBuiltin flag is set, then search the built-in
+  ** functions even if a prior app-defined function was found.  And give
+  ** priority to built-in functions.
+  **
   ** Except, if createFlag is true, that means that we are trying to
-  ** install a new function.  Whatever FuncDef structure is returned will
+  ** install a new function.  Whatever FuncDef structure is returned it will
   ** have fields overwritten with new information appropriate for the
   ** new function.  But the FuncDefs for built-in functions are read-only.
   ** So we must not search for built-ins when creating a new function.
   */ 
-  if( !createFlag && !pBest ){
+  if( !createFlag && (pBest==0 || (db->flags & SQLITE_PreferBuiltin)!=0) ){
     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
+    bestScore = 0;
     p = functionSearch(pHash, h, zName, nName);
     while( p ){
       int score = matchQuality(p, nArg, enc);
@@ -65155,7 +84379,7 @@ SQLITE_PRIVATE FuncDef *sqlite3FindFunction(
   ** exact match for the name, number of arguments and encoding, then add a
   ** new entry to the hash table and return it.
   */
-  if( createFlag && (bestScore<6 || pBest->nArg!=nArg) && 
+  if( createFlag && bestScore<FUNC_PERFECT_MATCH && 
       (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
     pBest->zName = (char *)&pBest[1];
     pBest->nArg = (u16)nArg;
@@ -65174,12 +84398,12 @@ SQLITE_PRIVATE FuncDef *sqlite3FindFunction(
 /*
 ** Free all resources held by the schema structure. The void* argument points
 ** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the 
-** pointer itself, it just cleans up subsiduary resources (i.e. the contents
+** pointer itself, it just cleans up subsidiary resources (i.e. the contents
 ** of the schema hash tables).
 **
 ** The Schema.cache_size variable is not cleared.
 */
-SQLITE_PRIVATE void sqlite3SchemaFree(void *p){
+SQLITE_PRIVATE void sqlite3SchemaClear(void *p){
   Hash temp1;
   Hash temp2;
   HashElem *pElem;
@@ -65187,21 +84411,24 @@ SQLITE_PRIVATE void sqlite3SchemaFree(void *p){
 
   temp1 = pSchema->tblHash;
   temp2 = pSchema->trigHash;
-  sqlite3HashInit(&pSchema->trigHash, 0);
-  sqlite3HashClear(&pSchema->aFKey);
+  sqlite3HashInit(&pSchema->trigHash);
   sqlite3HashClear(&pSchema->idxHash);
   for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
     sqlite3DeleteTrigger(0, (Trigger*)sqliteHashData(pElem));
   }
   sqlite3HashClear(&temp2);
-  sqlite3HashInit(&pSchema->tblHash, 0);
+  sqlite3HashInit(&pSchema->tblHash);
   for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){
     Table *pTab = sqliteHashData(pElem);
-    sqlite3DeleteTable(pTab);
+    sqlite3DeleteTable(0, pTab);
   }
   sqlite3HashClear(&temp1);
+  sqlite3HashClear(&pSchema->fkeyHash);
   pSchema->pSeqTab = 0;
-  pSchema->flags &= ~DB_SchemaLoaded;
+  if( pSchema->flags & DB_SchemaLoaded ){
+    pSchema->iGeneration++;
+    pSchema->flags &= ~DB_SchemaLoaded;
+  }
 }
 
 /*
@@ -65211,17 +84438,17 @@ SQLITE_PRIVATE void sqlite3SchemaFree(void *p){
 SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
   Schema * p;
   if( pBt ){
-    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaFree);
+    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
   }else{
-    p = (Schema *)sqlite3MallocZero(sizeof(Schema));
+    p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
   }
   if( !p ){
     db->mallocFailed = 1;
   }else if ( 0==p->file_format ){
-    sqlite3HashInit(&p->tblHash, 0);
-    sqlite3HashInit(&p->idxHash, 0);
-    sqlite3HashInit(&p->trigHash, 0);
-    sqlite3HashInit(&p->aFKey, 1);
+    sqlite3HashInit(&p->tblHash);
+    sqlite3HashInit(&p->idxHash);
+    sqlite3HashInit(&p->trigHash);
+    sqlite3HashInit(&p->fkeyHash);
     p->enc = SQLITE_UTF8;
   }
   return p;
@@ -65242,21 +84469,28 @@ SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** in order to generate code for DELETE FROM statements.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
-** Look up every table that is named in pSrc.  If any table is not found,
-** add an error message to pParse->zErrMsg and return NULL.  If all tables
-** are found, return a pointer to the last table.
+** While a SrcList can in general represent multiple tables and subqueries
+** (as in the FROM clause of a SELECT statement) in this case it contains
+** the name of a single table, as one might find in an INSERT, DELETE,
+** or UPDATE statement.  Look up that table in the symbol table and
+** return a pointer.  Set an error message and return NULL if the table 
+** name is not found or if any other error occurs.
+**
+** The following fields are initialized appropriate in pSrc:
+**
+**    pSrc->a[0].pTab       Pointer to the Table object
+**    pSrc->a[0].pIndex     Pointer to the INDEXED BY index, if there is one
+**
 */
 SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
   struct SrcList_item *pItem = pSrc->a;
   Table *pTab;
   assert( pItem && pSrc->nSrc==1 );
   pTab = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
-  sqlite3DeleteTable(pItem->pTab);
+  sqlite3DeleteTable(pParse->db, pItem->pTab);
   pItem->pTab = pTab;
   if( pTab ){
     pTab->nRef++;
@@ -65273,16 +84507,26 @@ SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
 ** writable return 0;
 */
 SQLITE_PRIVATE int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
-  if( ((pTab->tabFlags & TF_Readonly)!=0
-        && (pParse->db->flags & SQLITE_WriteSchema)==0
-        && pParse->nested==0) 
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-      || (pTab->pMod && pTab->pMod->pModule->xUpdate==0)
-#endif
+  /* A table is not writable under the following circumstances:
+  **
+  **   1) It is a virtual table and no implementation of the xUpdate method
+  **      has been provided, or
+  **   2) It is a system table (i.e. sqlite_master), this call is not
+  **      part of a nested parse and writable_schema pragma has not 
+  **      been specified.
+  **
+  ** In either case leave an error message in pParse and return non-zero.
+  */
+  if( ( IsVirtual(pTab) 
+     && sqlite3GetVTable(pParse->db, pTab)->pMod->pModule->xUpdate==0 )
+   || ( (pTab->tabFlags & TF_Readonly)!=0
+     && (pParse->db->flags & SQLITE_WriteSchema)==0
+     && pParse->nested==0 )
   ){
     sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
     return 1;
   }
+
 #ifndef SQLITE_OMIT_VIEW
   if( !viewOk && pTab->pSelect ){
     sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
@@ -65292,26 +84536,6 @@ SQLITE_PRIVATE int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
   return 0;
 }
 
-/*
-** Generate code that will open a table for reading.
-*/
-SQLITE_PRIVATE void sqlite3OpenTable(
-  Parse *p,       /* Generate code into this VDBE */
-  int iCur,       /* The cursor number of the table */
-  int iDb,        /* The database index in sqlite3.aDb[] */
-  Table *pTab,    /* The table to be opened */
-  int opcode      /* OP_OpenRead or OP_OpenWrite */
-){
-  Vdbe *v;
-  if( IsVirtual(pTab) ) return;
-  v = sqlite3GetVdbe(p);
-  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
-  sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite)?1:0, pTab->zName);
-  sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
-  sqlite3VdbeAddOp3(v, opcode, iCur, pTab->tnum, iDb);
-  VdbeComment((v, "%s", pTab->zName));
-}
-
 
 #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
 /*
@@ -65329,15 +84553,21 @@ SQLITE_PRIVATE void sqlite3MaterializeView(
   Select *pDup;
   sqlite3 *db = pParse->db;
 
-  pDup = sqlite3SelectDup(db, pView->pSelect);
+  pDup = sqlite3SelectDup(db, pView->pSelect, 0);
   if( pWhere ){
     SrcList *pFrom;
-    Token viewName;
     
-    pWhere = sqlite3ExprDup(db, pWhere);
-    viewName.z = (u8*)pView->zName;
-    viewName.n = (unsigned int)sqlite3Strlen30((const char*)viewName.z);
-    pFrom = sqlite3SrcListAppendFromTerm(pParse, 0, 0, 0, &viewName, pDup, 0,0);
+    pWhere = sqlite3ExprDup(db, pWhere, 0);
+    pFrom = sqlite3SrcListAppend(db, 0, 0, 0);
+    if( pFrom ){
+      assert( pFrom->nSrc==1 );
+      pFrom->a[0].zAlias = sqlite3DbStrDup(db, pView->zName);
+      pFrom->a[0].pSelect = pDup;
+      assert( pFrom->a[0].pOn==0 );
+      assert( pFrom->a[0].pUsing==0 );
+    }else{
+      sqlite3SelectDelete(db, pDup);
+    }
     pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
   }
   sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
@@ -65375,7 +84605,6 @@ SQLITE_PRIVATE Expr *sqlite3LimitWhere(
   */
   if( pOrderBy && (pLimit == 0) ) {
     sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType);
-    pParse->parseError = 1;
     goto limit_where_cleanup_2;
   }
 
@@ -65397,30 +84626,32 @@ SQLITE_PRIVATE Expr *sqlite3LimitWhere(
   **   );
   */
 
-  pSelectRowid = sqlite3Expr(pParse->db, TK_ROW, 0, 0, 0);
+  pSelectRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0, 0);
   if( pSelectRowid == 0 ) goto limit_where_cleanup_2;
-  pEList = sqlite3ExprListAppend(pParse, 0, pSelectRowid, 0);
+  pEList = sqlite3ExprListAppend(pParse, 0, pSelectRowid);
   if( pEList == 0 ) goto limit_where_cleanup_2;
 
   /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
   ** and the SELECT subtree. */
-  pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc);
+  pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc, 0);
   if( pSelectSrc == 0 ) {
     sqlite3ExprListDelete(pParse->db, pEList);
     goto limit_where_cleanup_2;
   }
 
   /* generate the SELECT expression tree. */
-  pSelect = sqlite3SelectNew(pParse,pEList,pSelectSrc,pWhere,0,0,pOrderBy,0,pLimit,pOffset);
+  pSelect = sqlite3SelectNew(pParse,pEList,pSelectSrc,pWhere,0,0,
+                             pOrderBy,0,pLimit,pOffset);
   if( pSelect == 0 ) return 0;
 
   /* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */
-  pWhereRowid = sqlite3Expr(pParse->db, TK_ROW, 0, 0, 0);
+  pWhereRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0, 0);
   if( pWhereRowid == 0 ) goto limit_where_cleanup_1;
   pInClause = sqlite3PExpr(pParse, TK_IN, pWhereRowid, 0, 0);
   if( pInClause == 0 ) goto limit_where_cleanup_1;
 
-  pInClause->pSelect = pSelect;
+  pInClause->x.pSelect = pSelect;
+  pInClause->flags |= EP_xIsSelect;
   sqlite3ExprSetHeight(pParse, pInClause);
   return pInClause;
 
@@ -65460,7 +84691,6 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
   int iCur;              /* VDBE Cursor number for pTab */
   sqlite3 *db;           /* Main database structure */
   AuthContext sContext;  /* Authorization context */
-  int oldIdx = -1;       /* Cursor for the OLD table of AFTER triggers */
   NameContext sNC;       /* Name context to resolve expressions in */
   int iDb;               /* Database number */
   int memCnt = -1;       /* Memory cell used for change counting */
@@ -65468,15 +84698,10 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
 
 #ifndef SQLITE_OMIT_TRIGGER
   int isView;                  /* True if attempting to delete from a view */
-  int triggers_exist = 0;      /* True if any triggers exist */
+  Trigger *pTrigger;           /* List of table triggers, if required */
 #endif
-  int iBeginAfterTrigger = 0;  /* Address of after trigger program */
-  int iEndAfterTrigger = 0;    /* Exit of after trigger program */
-  int iBeginBeforeTrigger = 0; /* Address of before trigger program */
-  int iEndBeforeTrigger = 0;   /* Exit of before trigger program */
-  u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
 
-  sContext.pParse = 0;
+  memset(&sContext, 0, sizeof(sContext));
   db = pParse->db;
   if( pParse->nErr || db->mallocFailed ){
     goto delete_from_cleanup;
@@ -65495,10 +84720,10 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
   ** deleted from is a view
   */
 #ifndef SQLITE_OMIT_TRIGGER
-  triggers_exist = sqlite3TriggersExist(pTab, TK_DELETE, 0);
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
   isView = pTab->pSelect!=0;
 #else
-# define triggers_exist 0
+# define pTrigger 0
 # define isView 0
 #endif
 #ifdef SQLITE_OMIT_VIEW
@@ -65506,7 +84731,13 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
 # define isView 0
 #endif
 
-  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
+  /* If pTab is really a view, make sure it has been initialized.
+  */
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto delete_from_cleanup;
+  }
+
+  if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){
     goto delete_from_cleanup;
   }
   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
@@ -65517,19 +84748,7 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
   if( rcauth==SQLITE_DENY ){
     goto delete_from_cleanup;
   }
-  assert(!isView || triggers_exist);
-
-  /* If pTab is really a view, make sure it has been initialized.
-  */
-  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
-    goto delete_from_cleanup;
-  }
-
-  /* Allocate a cursor used to store the old.* data for a trigger.
-  */
-  if( triggers_exist ){ 
-    oldIdx = pParse->nTab++;
-  }
+  assert(!isView || pTrigger);
 
   /* Assign  cursor number to the table and all its indices.
   */
@@ -65552,25 +84771,7 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
     goto delete_from_cleanup;
   }
   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
-  sqlite3BeginWriteOperation(pParse, triggers_exist, iDb);
-
-  if( triggers_exist ){
-    int orconf = ((pParse->trigStack)?pParse->trigStack->orconf:OE_Default);
-    int iGoto = sqlite3VdbeAddOp0(v, OP_Goto);
-    addr = sqlite3VdbeMakeLabel(v);
-
-    iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
-    (void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TRIGGER_BEFORE, pTab,
-        -1, oldIdx, orconf, addr, &old_col_mask, 0);
-    iEndBeforeTrigger = sqlite3VdbeAddOp0(v, OP_Goto);
-
-    iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v);
-    (void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TRIGGER_AFTER, pTab, -1,
-        oldIdx, orconf, addr, &old_col_mask, 0);
-    iEndAfterTrigger = sqlite3VdbeAddOp0(v, OP_Goto);
-
-    sqlite3VdbeJumpHere(v, iGoto);
-  }
+  sqlite3BeginWriteOperation(pParse, 1, iDb);
 
   /* If we are trying to delete from a view, realize that view into
   ** a ephemeral table.
@@ -65600,15 +84801,15 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
 
 #ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
   /* Special case: A DELETE without a WHERE clause deletes everything.
-  ** It is easier just to erase the whole table.  Note, however, that
-  ** this means that the row change count will be incorrect.
-  */
-  if( rcauth==SQLITE_OK && pWhere==0 && !triggers_exist && !IsVirtual(pTab) ){
+  ** It is easier just to erase the whole table. Prior to version 3.6.5,
+  ** this optimization caused the row change count (the value returned by 
+  ** API function sqlite3_count_changes) to be set incorrectly.  */
+  if( rcauth==SQLITE_OK && pWhere==0 && !pTrigger && !IsVirtual(pTab) 
+   && 0==sqlite3FkRequired(pParse, pTab, 0, 0)
+  ){
     assert( !isView );
-    sqlite3VdbeAddOp3(v, OP_Clear, pTab->tnum, iDb, memCnt);
-    if( !pParse->nested ){
-      sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
-    }
+    sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt,
+                      pTab->zName, P4_STATIC);
     for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
       assert( pIdx->pSchema==pTab->pSchema );
       sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb);
@@ -65619,98 +84820,60 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
   ** the table and pick which records to delete.
   */
   {
-    int iRowid = ++pParse->nMem;    /* Used for storing rowid values. */
     int iRowSet = ++pParse->nMem;   /* Register for rowset of rows to delete */
+    int iRowid = ++pParse->nMem;    /* Used for storing rowid values. */
+    int regRowid;                   /* Actual register containing rowids */
 
     /* Collect rowids of every row to be deleted.
     */
     sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
-    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
-                               WHERE_FILL_ROWSET, iRowSet);
+    pWInfo = sqlite3WhereBegin(
+        pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK, 0
+    );
     if( pWInfo==0 ) goto delete_from_cleanup;
+    regRowid = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, iRowid, 0);
+    sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, regRowid);
     if( db->flags & SQLITE_CountRows ){
       sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
     }
     sqlite3WhereEnd(pWInfo);
 
-    /* Open the pseudo-table used to store OLD if there are triggers.
-    */
-    if( triggers_exist ){
-      sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
-      sqlite3VdbeAddOp1(v, OP_OpenPseudo, oldIdx);
-    }
-
     /* Delete every item whose key was written to the list during the
     ** database scan.  We have to delete items after the scan is complete
-    ** because deleting an item can change the scan order.
-    */
+    ** because deleting an item can change the scan order.  */
     end = sqlite3VdbeMakeLabel(v);
 
+    /* Unless this is a view, open cursors for the table we are 
+    ** deleting from and all its indices. If this is a view, then the
+    ** only effect this statement has is to fire the INSTEAD OF 
+    ** triggers.  */
     if( !isView ){
-      /* Open cursors for the table we are deleting from and 
-      ** all its indices.
-      */
       sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);
     }
 
-    /* This is the beginning of the delete loop. If a trigger encounters
-    ** an IGNORE constraint, it jumps back to here.
-    */
-    if( triggers_exist ){
-      sqlite3VdbeResolveLabel(v, addr);
-    }
     addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, end, iRowid);
 
-    if( triggers_exist ){
-      int iData = ++pParse->nMem;   /* For storing row data of OLD table */
-
-      /* If the record is no longer present in the table, jump to the
-      ** next iteration of the loop through the contents of the fifo.
-      */
-      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid);
-
-      /* Populate the OLD.* pseudo-table */
-      if( old_col_mask ){
-        sqlite3VdbeAddOp2(v, OP_RowData, iCur, iData);
-      }else{
-        sqlite3VdbeAddOp2(v, OP_Null, 0, iData);
-      }
-      sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, iData, iRowid);
-
-      /* Jump back and run the BEFORE triggers */
-      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
-      sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
-    }
-
-    if( !isView ){
-      /* Delete the row */
+    /* Delete the row */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-      if( IsVirtual(pTab) ){
-        const char *pVtab = (const char *)pTab->pVtab;
-        sqlite3VtabMakeWritable(pParse, pTab);
-        sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVtab, P4_VTAB);
-      }else
+    if( IsVirtual(pTab) ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
+      sqlite3VtabMakeWritable(pParse, pTab);
+      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB);
+      sqlite3VdbeChangeP5(v, OE_Abort);
+      sqlite3MayAbort(pParse);
+    }else
 #endif
-      {
-        sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, pParse->nested==0);
-      }
-    }
-
-    /* If there are row triggers, close all cursors then invoke
-    ** the AFTER triggers
-    */
-    if( triggers_exist ){
-      /* Jump back and run the AFTER triggers */
-      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
-      sqlite3VdbeJumpHere(v, iEndAfterTrigger);
+    {
+      int count = (pParse->nested==0);    /* True to count changes */
+      sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, count, pTrigger, OE_Default);
     }
 
     /* End of the delete loop */
     sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
     sqlite3VdbeResolveLabel(v, end);
 
-    /* Close the cursors after the loop if there are no row triggers */
-    if( !isView  && !IsVirtual(pTab) ){
+    /* Close the cursors open on the table and its indexes. */
+    if( !isView && !IsVirtual(pTab) ){
       for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
         sqlite3VdbeAddOp2(v, OP_Close, iCur + i, pIdx->tnum);
       }
@@ -65718,12 +84881,19 @@ SQLITE_PRIVATE void sqlite3DeleteFrom(
     }
   }
 
-  /*
-  ** Return the number of rows that were deleted. If this routine is 
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
+
+  /* Return the number of rows that were deleted. If this routine is 
   ** generating code because of a call to sqlite3NestedParse(), do not
   ** invoke the callback function.
   */
-  if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){
+  if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
     sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1);
     sqlite3VdbeSetNumCols(v, 1);
     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC);
@@ -65735,6 +84905,15 @@ delete_from_cleanup:
   sqlite3ExprDelete(db, pWhere);
   return;
 }
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** thely may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
 
 /*
 ** This routine generates VDBE code that causes a single row of a
@@ -65744,7 +84923,7 @@ delete_from_cleanup:
 ** These are the requirements:
 **
 **   1.  A read/write cursor pointing to pTab, the table containing the row
-**       to be deleted, must be opened as cursor number "base".
+**       to be deleted, must be opened as cursor number $iCur.
 **
 **   2.  Read/write cursors for all indices of pTab must be open as
 **       cursor number base+i for the i-th index.
@@ -65752,28 +84931,97 @@ delete_from_cleanup:
 **   3.  The record number of the row to be deleted must be stored in
 **       memory cell iRowid.
 **
-** This routine pops the top of the stack to remove the record number
-** and then generates code to remove both the table record and all index
-** entries that point to that record.
+** This routine generates code to remove both the table record and all 
+** index entries that point to that record.
 */
 SQLITE_PRIVATE void sqlite3GenerateRowDelete(
   Parse *pParse,     /* Parsing context */
   Table *pTab,       /* Table containing the row to be deleted */
   int iCur,          /* Cursor number for the table */
   int iRowid,        /* Memory cell that contains the rowid to delete */
-  int count          /* Increment the row change counter */
+  int count,         /* If non-zero, increment the row change counter */
+  Trigger *pTrigger, /* List of triggers to (potentially) fire */
+  int onconf         /* Default ON CONFLICT policy for triggers */
 ){
-  int addr;
-  Vdbe *v;
+  Vdbe *v = pParse->pVdbe;        /* Vdbe */
+  int iOld = 0;                   /* First register in OLD.* array */
+  int iLabel;                     /* Label resolved to end of generated code */
 
-  v = pParse->pVdbe;
-  addr = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowid);
-  sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, 0);
-  sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
-  if( count ){
-    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
+  /* Vdbe is guaranteed to have been allocated by this stage. */
+  assert( v );
+
+  /* Seek cursor iCur to the row to delete. If this row no longer exists 
+  ** (this can happen if a trigger program has already deleted it), do
+  ** not attempt to delete it or fire any DELETE triggers.  */
+  iLabel = sqlite3VdbeMakeLabel(v);
+  sqlite3VdbeAddOp3(v, OP_NotExists, iCur, iLabel, iRowid);
+ 
+  /* If there are any triggers to fire, allocate a range of registers to
+  ** use for the old.* references in the triggers.  */
+  if( sqlite3FkRequired(pParse, pTab, 0, 0) || pTrigger ){
+    u32 mask;                     /* Mask of OLD.* columns in use */
+    int iCol;                     /* Iterator used while populating OLD.* */
+
+    /* TODO: Could use temporary registers here. Also could attempt to
+    ** avoid copying the contents of the rowid register.  */
+    mask = sqlite3TriggerColmask(
+        pParse, pTrigger, 0, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onconf
+    );
+    mask |= sqlite3FkOldmask(pParse, pTab);
+    iOld = pParse->nMem+1;
+    pParse->nMem += (1 + pTab->nCol);
+
+    /* Populate the OLD.* pseudo-table register array. These values will be 
+    ** used by any BEFORE and AFTER triggers that exist.  */
+    sqlite3VdbeAddOp2(v, OP_Copy, iRowid, iOld);
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      if( mask==0xffffffff || mask&(1<<iCol) ){
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol, iOld+iCol+1);
+      }
+    }
+
+    /* Invoke BEFORE DELETE trigger programs. */
+    sqlite3CodeRowTrigger(pParse, pTrigger, 
+        TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel
+    );
+
+    /* Seek the cursor to the row to be deleted again. It may be that
+    ** the BEFORE triggers coded above have already removed the row
+    ** being deleted. Do not attempt to delete the row a second time, and 
+    ** do not fire AFTER triggers.  */
+    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, iLabel, iRowid);
+
+    /* Do FK processing. This call checks that any FK constraints that
+    ** refer to this table (i.e. constraints attached to other tables) 
+    ** are not violated by deleting this row.  */
+    sqlite3FkCheck(pParse, pTab, iOld, 0);
   }
-  sqlite3VdbeJumpHere(v, addr);
+
+  /* Delete the index and table entries. Skip this step if pTab is really
+  ** a view (in which case the only effect of the DELETE statement is to
+  ** fire the INSTEAD OF triggers).  */ 
+  if( pTab->pSelect==0 ){
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, 0);
+    sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
+    if( count ){
+      sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_TRANSIENT);
+    }
+  }
+
+  /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+  ** handle rows (possibly in other tables) that refer via a foreign key
+  ** to the row just deleted. */ 
+  sqlite3FkActions(pParse, pTab, 0, iOld);
+
+  /* Invoke AFTER DELETE trigger programs. */
+  sqlite3CodeRowTrigger(pParse, pTrigger, 
+      TK_DELETE, 0, TRIGGER_AFTER, pTab, iOld, onconf, iLabel
+  );
+
+  /* Jump here if the row had already been deleted before any BEFORE
+  ** trigger programs were invoked. Or if a trigger program throws a 
+  ** RAISE(IGNORE) exception.  */
+  sqlite3VdbeResolveLabel(v, iLabel);
 }
 
 /*
@@ -65842,23 +85090,23 @@ SQLITE_PRIVATE int sqlite3GenerateIndexKey(
       sqlite3VdbeAddOp2(v, OP_SCopy, regBase+nCol, regBase+j);
     }else{
       sqlite3VdbeAddOp3(v, OP_Column, iCur, idx, regBase+j);
-      sqlite3ColumnDefault(v, pTab, idx);
+      sqlite3ColumnDefault(v, pTab, idx, -1);
     }
   }
   if( doMakeRec ){
+    const char *zAff;
+    if( pTab->pSelect || (pParse->db->flags & SQLITE_IdxRealAsInt)!=0 ){
+      zAff = 0;
+    }else{
+      zAff = sqlite3IndexAffinityStr(v, pIdx);
+    }
     sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol+1, regOut);
-    sqlite3IndexAffinityStr(v, pIdx);
-    sqlite3ExprCacheAffinityChange(pParse, regBase, nCol+1);
+    sqlite3VdbeChangeP4(v, -1, zAff, P4_TRANSIENT);
   }
   sqlite3ReleaseTempRange(pParse, regBase, nCol+1);
   return regBase;
 }
 
-/* Make sure "isView" gets undefined in case this file becomes part of
-** the amalgamation - so that subsequent files do not see isView as a
-** macro. */
-#undef isView
-
 /************** End of delete.c **********************************************/
 /************** Begin file func.c ********************************************/
 /*
@@ -65878,9 +85126,9 @@ SQLITE_PRIVATE int sqlite3GenerateIndexKey(
 ** There is only one exported symbol in this file - the function
 ** sqliteRegisterBuildinFunctions() found at the bottom of the file.
 ** All other code has file scope.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/* #include <stdlib.h> */
+/* #include <assert.h> */
 
 /*
 ** Return the collating function associated with a function.
@@ -65889,6 +85137,14 @@ static CollSeq *sqlite3GetFuncCollSeq(sqlite3_context *context){
   return context->pColl;
 }
 
+/*
+** Indicate that the accumulator load should be skipped on this
+** iteration of the aggregate loop.
+*/
+static void sqlite3SkipAccumulatorLoad(sqlite3_context *context){
+  context->skipFlag = 1;
+}
+
 /*
 ** Implementation of the non-aggregate min() and max() functions
 */
@@ -65902,7 +85158,7 @@ static void minmaxFunc(
   int iBest;
   CollSeq *pColl;
 
-  if( argc==0 ) return;
+  assert( argc>1 );
   mask = sqlite3_user_data(context)==0 ? 0 : -1;
   pColl = sqlite3GetFuncCollSeq(context);
   assert( pColl );
@@ -65912,6 +85168,7 @@ static void minmaxFunc(
   for(i=1; i<argc; i++){
     if( sqlite3_value_type(argv[i])==SQLITE_NULL ) return;
     if( (sqlite3MemCompare(argv[iBest], argv[i], pColl)^mask)>=0 ){
+      testcase( mask==0 );
       iBest = i;
     }
   }
@@ -65929,11 +85186,11 @@ static void typeofFunc(
   const char *z = 0;
   UNUSED_PARAMETER(NotUsed);
   switch( sqlite3_value_type(argv[0]) ){
-    case SQLITE_NULL:    z = "null";    break;
     case SQLITE_INTEGER: z = "integer"; break;
     case SQLITE_TEXT:    z = "text";    break;
     case SQLITE_FLOAT:   z = "real";    break;
     case SQLITE_BLOB:    z = "blob";    break;
+    default:             z = "null";    break;
   }
   sqlite3_result_text(context, z, -1, SQLITE_STATIC);
 }
@@ -65977,7 +85234,10 @@ static void lengthFunc(
 }
 
 /*
-** Implementation of the abs() function
+** Implementation of the abs() function.
+**
+** IMP: R-23979-26855 The abs(X) function returns the absolute value of
+** the numeric argument X. 
 */
 static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   assert( argc==1 );
@@ -65987,6 +85247,9 @@ static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
       i64 iVal = sqlite3_value_int64(argv[0]);
       if( iVal<0 ){
         if( (iVal<<1)==0 ){
+          /* IMP: R-35460-15084 If X is the integer -9223372036854775807 then
+          ** abs(X) throws an integer overflow error since there is no
+          ** equivalent positive 64-bit two complement value. */
           sqlite3_result_error(context, "integer overflow", -1);
           return;
         }
@@ -65996,10 +85259,16 @@ static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
       break;
     }
     case SQLITE_NULL: {
+      /* IMP: R-37434-19929 Abs(X) returns NULL if X is NULL. */
       sqlite3_result_null(context);
       break;
     }
     default: {
+      /* Because sqlite3_value_double() returns 0.0 if the argument is not
+      ** something that can be converted into a number, we have:
+      ** IMP: R-57326-31541 Abs(X) return 0.0 if X is a string or blob that
+      ** cannot be converted to a numeric value. 
+      */
       double rVal = sqlite3_value_double(argv[0]);
       if( rVal<0 ) rVal = -rVal;
       sqlite3_result_double(context, rVal);
@@ -66017,6 +85286,8 @@ static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
 ** If x is a blob, then we count bytes.
 **
 ** If p1 is negative, then we begin abs(p1) from the end of x[].
+**
+** If p2 is negative, return the p2 characters preceeding p1.
 */
 static void substrFunc(
   sqlite3_context *context,
@@ -66028,9 +85299,16 @@ static void substrFunc(
   int len;
   int p0type;
   i64 p1, p2;
+  int negP2 = 0;
 
   assert( argc==3 || argc==2 );
+  if( sqlite3_value_type(argv[1])==SQLITE_NULL
+   || (argc==3 && sqlite3_value_type(argv[2])==SQLITE_NULL)
+  ){
+    return;
+  }
   p0type = sqlite3_value_type(argv[0]);
+  p1 = sqlite3_value_int(argv[1]);
   if( p0type==SQLITE_BLOB ){
     len = sqlite3_value_bytes(argv[0]);
     z = sqlite3_value_blob(argv[0]);
@@ -66040,13 +85318,18 @@ static void substrFunc(
     z = sqlite3_value_text(argv[0]);
     if( z==0 ) return;
     len = 0;
-    for(z2=z; *z2; len++){
-      SQLITE_SKIP_UTF8(z2);
+    if( p1<0 ){
+      for(z2=z; *z2; len++){
+        SQLITE_SKIP_UTF8(z2);
+      }
     }
   }
-  p1 = sqlite3_value_int(argv[1]);
   if( argc==3 ){
     p2 = sqlite3_value_int(argv[2]);
+    if( p2<0 ){
+      p2 = -p2;
+      negP2 = 1;
+    }
   }else{
     p2 = sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH];
   }
@@ -66054,14 +85337,22 @@ static void substrFunc(
     p1 += len;
     if( p1<0 ){
       p2 += p1;
+      if( p2<0 ) p2 = 0;
       p1 = 0;
     }
   }else if( p1>0 ){
     p1--;
+  }else if( p2>0 ){
+    p2--;
   }
-  if( p1+p2>len ){
-    p2 = len-p1;
+  if( negP2 ){
+    p1 -= p2;
+    if( p1<0 ){
+      p2 += p1;
+      p1 = 0;
+    }
   }
+  assert( p1>=0 && p2>=0 );
   if( p0type!=SQLITE_BLOB ){
     while( *z && p1 ){
       SQLITE_SKIP_UTF8(z);
@@ -66072,7 +85363,10 @@ static void substrFunc(
     }
     sqlite3_result_text(context, (char*)z, (int)(z2-z), SQLITE_TRANSIENT);
   }else{
-    if( p2<0 ) p2 = 0;
+    if( p1+p2>len ){
+      p2 = len-p1;
+      if( p2<0 ) p2 = 0;
+    }
     sqlite3_result_blob(context, (char*)&z[p1], (int)p2, SQLITE_TRANSIENT);
   }
 }
@@ -66080,10 +85374,11 @@ static void substrFunc(
 /*
 ** Implementation of the round() function
 */
+#ifndef SQLITE_OMIT_FLOATING_POINT
 static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   int n = 0;
   double r;
-  char zBuf[500];  /* larger than the %f representation of the largest double */
+  char *zBuf;
   assert( argc==1 || argc==2 );
   if( argc==2 ){
     if( SQLITE_NULL==sqlite3_value_type(argv[1]) ) return;
@@ -66093,24 +85388,46 @@ static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   }
   if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
   r = sqlite3_value_double(argv[0]);
-  sqlite3_snprintf(sizeof(zBuf),zBuf,"%.*f",n,r);
-  sqlite3AtoF(zBuf, &r);
+  /* If Y==0 and X will fit in a 64-bit int,
+  ** handle the rounding directly,
+  ** otherwise use printf.
+  */
+  if( n==0 && r>=0 && r<LARGEST_INT64-1 ){
+    r = (double)((sqlite_int64)(r+0.5));
+  }else if( n==0 && r<0 && (-r)<LARGEST_INT64-1 ){
+    r = -(double)((sqlite_int64)((-r)+0.5));
+  }else{
+    zBuf = sqlite3_mprintf("%.*f",n,r);
+    if( zBuf==0 ){
+      sqlite3_result_error_nomem(context);
+      return;
+    }
+    sqlite3AtoF(zBuf, &r, sqlite3Strlen30(zBuf), SQLITE_UTF8);
+    sqlite3_free(zBuf);
+  }
   sqlite3_result_double(context, r);
 }
+#endif
 
 /*
 ** Allocate nByte bytes of space using sqlite3_malloc(). If the
 ** allocation fails, call sqlite3_result_error_nomem() to notify
-** the database handle that malloc() has failed.
+** the database handle that malloc() has failed and return NULL.
+** If nByte is larger than the maximum string or blob length, then
+** raise an SQLITE_TOOBIG exception and return NULL.
 */
 static void *contextMalloc(sqlite3_context *context, i64 nByte){
   char *z;
-  if( nByte>sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH] ){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  assert( nByte>0 );
+  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH] );
+  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH]+1 );
+  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
     sqlite3_result_error_toobig(context);
     z = 0;
   }else{
     z = sqlite3Malloc((int)nByte);
-    if( !z && nByte>0 ){
+    if( !z ){
       sqlite3_result_error_nomem(context);
     }
   }
@@ -66124,7 +85441,7 @@ static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   char *z1;
   const char *z2;
   int i, n;
-  if( argc<1 || SQLITE_NULL==sqlite3_value_type(argv[0]) ) return;
+  UNUSED_PARAMETER(argc);
   z2 = (char*)sqlite3_value_text(argv[0]);
   n = sqlite3_value_bytes(argv[0]);
   /* Verify that the call to _bytes() does not invalidate the _text() pointer */
@@ -66132,11 +85449,10 @@ static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   if( z2 ){
     z1 = contextMalloc(context, ((i64)n)+1);
     if( z1 ){
-      memcpy(z1, z2, n+1);
-      for(i=0; z1[i]; i++){
-        z1[i] = (char)toupper(z1[i]);
+      for(i=0; i<n; i++){
+        z1[i] = (char)sqlite3Toupper(z2[i]);
       }
-      sqlite3_result_text(context, z1, -1, sqlite3_free);
+      sqlite3_result_text(context, z1, n, sqlite3_free);
     }
   }
 }
@@ -66144,7 +85460,7 @@ static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   char *z1;
   const char *z2;
   int i, n;
-  if( argc<1 || SQLITE_NULL==sqlite3_value_type(argv[0]) ) return;
+  UNUSED_PARAMETER(argc);
   z2 = (char*)sqlite3_value_text(argv[0]);
   n = sqlite3_value_bytes(argv[0]);
   /* Verify that the call to _bytes() does not invalidate the _text() pointer */
@@ -66152,15 +85468,22 @@ static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   if( z2 ){
     z1 = contextMalloc(context, ((i64)n)+1);
     if( z1 ){
-      memcpy(z1, z2, n+1);
-      for(i=0; z1[i]; i++){
-        z1[i] = (char)tolower(z1[i]);
+      for(i=0; i<n; i++){
+        z1[i] = sqlite3Tolower(z2[i]);
       }
-      sqlite3_result_text(context, z1, -1, sqlite3_free);
+      sqlite3_result_text(context, z1, n, sqlite3_free);
     }
   }
 }
 
+
+#if 0  /* This function is never used. */
+/*
+** The COALESCE() and IFNULL() functions used to be implemented as shown
+** here.  But now they are implemented as VDBE code so that unused arguments
+** do not have to be computed.  This legacy implementation is retained as
+** comment.
+*/
 /*
 ** Implementation of the IFNULL(), NVL(), and COALESCE() functions.  
 ** All three do the same thing.  They return the first non-NULL
@@ -66179,6 +85502,8 @@ static void ifnullFunc(
     }
   }
 }
+#endif /* NOT USED */
+#define ifnullFunc versionFunc   /* Substitute function - never called */
 
 /*
 ** Implementation of random().  Return a random integer.  
@@ -66191,8 +85516,17 @@ static void randomFunc(
   sqlite_int64 r;
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
   sqlite3_randomness(sizeof(r), &r);
-  if( (r<<1)==0 ) r = 0;  /* Prevent 0x8000.... as the result so that we */
-                          /* can always do abs() of the result */
+  if( r<0 ){
+    /* We need to prevent a random number of 0x8000000000000000 
+    ** (or -9223372036854775808) since when you do abs() of that
+    ** number of you get the same value back again.  To do this
+    ** in a way that is testable, mask the sign bit off of negative
+    ** values, resulting in a positive value.  Then take the 
+    ** 2s complement of that positive value.  The end result can
+    ** therefore be no less than -9223372036854775807.
+    */
+    r = -(r & LARGEST_INT64);
+  }
   sqlite3_result_int64(context, r);
 }
 
@@ -66231,12 +85565,18 @@ static void last_insert_rowid(
 ){
   sqlite3 *db = sqlite3_context_db_handle(context);
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-51513-12026 The last_insert_rowid() SQL function is a
+  ** wrapper around the sqlite3_last_insert_rowid() C/C++ interface
+  ** function. */
   sqlite3_result_int64(context, sqlite3_last_insert_rowid(db));
 }
 
 /*
-** Implementation of the changes() SQL function.  The return value is the
-** same as the sqlite3_changes() API function.
+** Implementation of the changes() SQL function.
+**
+** IMP: R-62073-11209 The changes() SQL function is a wrapper
+** around the sqlite3_changes() C/C++ function and hence follows the same
+** rules for counting changes.
 */
 static void changes(
   sqlite3_context *context,
@@ -66259,6 +85599,8 @@ static void total_changes(
 ){
   sqlite3 *db = sqlite3_context_db_handle(context);
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-52756-41993 This function is a wrapper around the
+  ** sqlite3_total_changes() C/C++ interface. */
   sqlite3_result_int(context, sqlite3_total_changes(db));
 }
 
@@ -66279,10 +85621,10 @@ struct compareInfo {
 ** whereas only characters less than 0x80 do in ASCII.
 */
 #if defined(SQLITE_EBCDIC)
-# define sqlite3Utf8Read(A,B,C)  (*(A++))
-# define GlogUpperToLower(A)     A = sqlite3UpperToLower[A]
+# define sqlite3Utf8Read(A,C)  (*(A++))
+# define GlogUpperToLower(A)   A = sqlite3UpperToLower[A]
 #else
-# define GlogUpperToLower(A)     if( A<0x80 ){ A = sqlite3UpperToLower[A]; }
+# define GlogUpperToLower(A)   if( !((A)&~0x7f) ){ A = sqlite3UpperToLower[A]; }
 #endif
 
 static const struct compareInfo globInfo = { '*', '?', '[', 0 };
@@ -66325,9 +85667,9 @@ static int patternCompare(
   const u8 *zPattern,              /* The glob pattern */
   const u8 *zString,               /* The string to compare against the glob */
   const struct compareInfo *pInfo, /* Information about how to do the compare */
-  const int esc                    /* The escape character */
+  u32 esc                          /* The escape character */
 ){
-  int c, c2;
+  u32 c, c2;
   int invert;
   int seen;
   u8 matchOne = pInfo->matchOne;
@@ -66336,18 +85678,18 @@ static int patternCompare(
   u8 noCase = pInfo->noCase; 
   int prevEscape = 0;     /* True if the previous character was 'escape' */
 
-  while( (c = sqlite3Utf8Read(zPattern,0,&zPattern))!=0 ){
+  while( (c = sqlite3Utf8Read(zPattern,&zPattern))!=0 ){
     if( !prevEscape && c==matchAll ){
-      while( (c=sqlite3Utf8Read(zPattern,0,&zPattern)) == matchAll
+      while( (c=sqlite3Utf8Read(zPattern,&zPattern)) == matchAll
                || c == matchOne ){
-        if( c==matchOne && sqlite3Utf8Read(zString, 0, &zString)==0 ){
+        if( c==matchOne && sqlite3Utf8Read(zString, &zString)==0 ){
           return 0;
         }
       }
       if( c==0 ){
         return 1;
       }else if( c==esc ){
-        c = sqlite3Utf8Read(zPattern, 0, &zPattern);
+        c = sqlite3Utf8Read(zPattern, &zPattern);
         if( c==0 ){
           return 0;
         }
@@ -66359,17 +85701,17 @@ static int patternCompare(
         }
         return *zString!=0;
       }
-      while( (c2 = sqlite3Utf8Read(zString,0,&zString))!=0 ){
+      while( (c2 = sqlite3Utf8Read(zString,&zString))!=0 ){
         if( noCase ){
           GlogUpperToLower(c2);
           GlogUpperToLower(c);
           while( c2 != 0 && c2 != c ){
-            c2 = sqlite3Utf8Read(zString, 0, &zString);
+            c2 = sqlite3Utf8Read(zString, &zString);
             GlogUpperToLower(c2);
           }
         }else{
           while( c2 != 0 && c2 != c ){
-            c2 = sqlite3Utf8Read(zString, 0, &zString);
+            c2 = sqlite3Utf8Read(zString, &zString);
           }
         }
         if( c2==0 ) return 0;
@@ -66377,28 +85719,28 @@ static int patternCompare(
       }
       return 0;
     }else if( !prevEscape && c==matchOne ){
-      if( sqlite3Utf8Read(zString, 0, &zString)==0 ){
+      if( sqlite3Utf8Read(zString, &zString)==0 ){
         return 0;
       }
     }else if( c==matchSet ){
-      int prior_c = 0;
+      u32 prior_c = 0;
       assert( esc==0 );    /* This only occurs for GLOB, not LIKE */
       seen = 0;
       invert = 0;
-      c = sqlite3Utf8Read(zString, 0, &zString);
+      c = sqlite3Utf8Read(zString, &zString);
       if( c==0 ) return 0;
-      c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+      c2 = sqlite3Utf8Read(zPattern, &zPattern);
       if( c2=='^' ){
         invert = 1;
-        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+        c2 = sqlite3Utf8Read(zPattern, &zPattern);
       }
       if( c2==']' ){
         if( c==']' ) seen = 1;
-        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+        c2 = sqlite3Utf8Read(zPattern, &zPattern);
       }
       while( c2 && c2!=']' ){
         if( c2=='-' && zPattern[0]!=']' && zPattern[0]!=0 && prior_c>0 ){
-          c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+          c2 = sqlite3Utf8Read(zPattern, &zPattern);
           if( c>=prior_c && c<=c2 ) seen = 1;
           prior_c = 0;
         }else{
@@ -66407,7 +85749,7 @@ static int patternCompare(
           }
           prior_c = c2;
         }
-        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
+        c2 = sqlite3Utf8Read(zPattern, &zPattern);
       }
       if( c2==0 || (seen ^ invert)==0 ){
         return 0;
@@ -66415,7 +85757,7 @@ static int patternCompare(
     }else if( esc==c && !prevEscape ){
       prevEscape = 1;
     }else{
-      c2 = sqlite3Utf8Read(zString, 0, &zString);
+      c2 = sqlite3Utf8Read(zString, &zString);
       if( noCase ){
         GlogUpperToLower(c);
         GlogUpperToLower(c2);
@@ -66457,7 +85799,8 @@ static void likeFunc(
   sqlite3_value **argv
 ){
   const unsigned char *zA, *zB;
-  int escape = 0;
+  u32 escape = 0;
+  int nPat;
   sqlite3 *db = sqlite3_context_db_handle(context);
 
   zB = sqlite3_value_text(argv[0]);
@@ -66466,8 +85809,10 @@ static void likeFunc(
   /* Limit the length of the LIKE or GLOB pattern to avoid problems
   ** of deep recursion and N*N behavior in patternCompare().
   */
-  if( sqlite3_value_bytes(argv[0]) >
-        db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] ){
+  nPat = sqlite3_value_bytes(argv[0]);
+  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] );
+  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]+1 );
+  if( nPat > db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] ){
     sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
     return;
   }
@@ -66484,7 +85829,7 @@ static void likeFunc(
           "ESCAPE expression must be a single character", -1);
       return;
     }
-    escape = sqlite3Utf8Read(zEsc, 0, &zEsc);
+    escape = sqlite3Utf8Read(zEsc, &zEsc);
   }
   if( zA && zB ){
     struct compareInfo *pInfo = sqlite3_user_data(context);
@@ -66514,7 +85859,7 @@ static void nullifFunc(
 }
 
 /*
-** Implementation of the VERSION(*) function.  The result is the version
+** Implementation of the sqlite_version() function.  The result is the version
 ** of the SQLite library that is running.
 */
 static void versionFunc(
@@ -66523,9 +85868,88 @@ static void versionFunc(
   sqlite3_value **NotUsed2
 ){
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
-  sqlite3_result_text(context, sqlite3_version, -1, SQLITE_STATIC);
+  /* IMP: R-48699-48617 This function is an SQL wrapper around the
+  ** sqlite3_libversion() C-interface. */
+  sqlite3_result_text(context, sqlite3_libversion(), -1, SQLITE_STATIC);
 }
 
+/*
+** Implementation of the sqlite_source_id() function. The result is a string
+** that identifies the particular version of the source code used to build
+** SQLite.
+*/
+static void sourceidFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-24470-31136 This function is an SQL wrapper around the
+  ** sqlite3_sourceid() C interface. */
+  sqlite3_result_text(context, sqlite3_sourceid(), -1, SQLITE_STATIC);
+}
+
+/*
+** Implementation of the sqlite_log() function.  This is a wrapper around
+** sqlite3_log().  The return value is NULL.  The function exists purely for
+** its side-effects.
+*/
+static void errlogFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(context);
+  sqlite3_log(sqlite3_value_int(argv[0]), "%s", sqlite3_value_text(argv[1]));
+}
+
+/*
+** Implementation of the sqlite_compileoption_used() function.
+** The result is an integer that identifies if the compiler option
+** was used to build SQLite.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+static void compileoptionusedFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zOptName;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  /* IMP: R-39564-36305 The sqlite_compileoption_used() SQL
+  ** function is a wrapper around the sqlite3_compileoption_used() C/C++
+  ** function.
+  */
+  if( (zOptName = (const char*)sqlite3_value_text(argv[0]))!=0 ){
+    sqlite3_result_int(context, sqlite3_compileoption_used(zOptName));
+  }
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/*
+** Implementation of the sqlite_compileoption_get() function. 
+** The result is a string that identifies the compiler options 
+** used to build SQLite.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+static void compileoptiongetFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int n;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  /* IMP: R-04922-24076 The sqlite_compileoption_get() SQL function
+  ** is a wrapper around the sqlite3_compileoption_get() C/C++ function.
+  */
+  n = sqlite3_value_int(argv[0]);
+  sqlite3_result_text(context, sqlite3_compileoption_get(n), -1, SQLITE_STATIC);
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
 /* Array for converting from half-bytes (nybbles) into ASCII hex
 ** digits. */
 static const char hexdigits[] = {
@@ -66545,14 +85969,22 @@ static const char hexdigits[] = {
 ** single-quote escapes.
 */
 static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
-  if( argc<1 ) return;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
   switch( sqlite3_value_type(argv[0]) ){
-    case SQLITE_NULL: {
-      sqlite3_result_text(context, "NULL", 4, SQLITE_STATIC);
+    case SQLITE_FLOAT: {
+      double r1, r2;
+      char zBuf[50];
+      r1 = sqlite3_value_double(argv[0]);
+      sqlite3_snprintf(sizeof(zBuf), zBuf, "%!.15g", r1);
+      sqlite3AtoF(zBuf, &r2, 20, SQLITE_UTF8);
+      if( r1!=r2 ){
+        sqlite3_snprintf(sizeof(zBuf), zBuf, "%!.20e", r1);
+      }
+      sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
       break;
     }
-    case SQLITE_INTEGER:
-    case SQLITE_FLOAT: {
+    case SQLITE_INTEGER: {
       sqlite3_result_value(context, argv[0]);
       break;
     }
@@ -66598,6 +86030,12 @@ static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
         z[j] = 0;
         sqlite3_result_text(context, z, j, sqlite3_free);
       }
+      break;
+    }
+    default: {
+      assert( sqlite3_value_type(argv[0])==SQLITE_NULL );
+      sqlite3_result_text(context, "NULL", 4, SQLITE_STATIC);
+      break;
     }
   }
 }
@@ -66640,13 +86078,16 @@ static void zeroblobFunc(
   sqlite3_value **argv
 ){
   i64 n;
+  sqlite3 *db = sqlite3_context_db_handle(context);
   assert( argc==1 );
   UNUSED_PARAMETER(argc);
   n = sqlite3_value_int64(argv[0]);
-  if( n>SQLITE_MAX_LENGTH ){
+  testcase( n==db->aLimit[SQLITE_LIMIT_LENGTH] );
+  testcase( n==db->aLimit[SQLITE_LIMIT_LENGTH]+1 );
+  if( n>db->aLimit[SQLITE_LIMIT_LENGTH] ){
     sqlite3_result_error_toobig(context);
   }else{
-    sqlite3_result_zeroblob(context, (int)n);
+    sqlite3_result_zeroblob(context, (int)n); /* IMP: R-00293-64994 */
   }
 }
 
@@ -66679,7 +86120,16 @@ static void replaceFunc(
   nStr = sqlite3_value_bytes(argv[0]);
   assert( zStr==sqlite3_value_text(argv[0]) );  /* No encoding change */
   zPattern = sqlite3_value_text(argv[1]);
-  if( zPattern==0 || zPattern[0]==0 ) return;
+  if( zPattern==0 ){
+    assert( sqlite3_value_type(argv[1])==SQLITE_NULL
+            || sqlite3_context_db_handle(context)->mallocFailed );
+    return;
+  }
+  if( zPattern[0]==0 ){
+    assert( sqlite3_value_type(argv[1])!=SQLITE_NULL );
+    sqlite3_result_value(context, argv[0]);
+    return;
+  }
   nPattern = sqlite3_value_bytes(argv[1]);
   assert( zPattern==sqlite3_value_text(argv[1]) );  /* No encoding change */
   zRep = sqlite3_value_text(argv[2]);
@@ -66700,16 +86150,18 @@ static void replaceFunc(
       u8 *zOld;
       sqlite3 *db = sqlite3_context_db_handle(context);
       nOut += nRep - nPattern;
-      if( nOut>=db->aLimit[SQLITE_LIMIT_LENGTH] ){
+      testcase( nOut-1==db->aLimit[SQLITE_LIMIT_LENGTH] );
+      testcase( nOut-2==db->aLimit[SQLITE_LIMIT_LENGTH] );
+      if( nOut-1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
         sqlite3_result_error_toobig(context);
-        sqlite3DbFree(db, zOut);
+        sqlite3_free(zOut);
         return;
       }
       zOld = zOut;
       zOut = sqlite3_realloc(zOut, (int)nOut);
       if( zOut==0 ){
         sqlite3_result_error_nomem(context);
-        sqlite3DbFree(db, zOld);
+        sqlite3_free(zOld);
         return;
       }
       memcpy(&zOut[j], zRep, nRep);
@@ -66784,7 +86236,7 @@ static void trimFunc(
         int len = 0;
         for(i=0; i<nChar; i++){
           len = aLen[i];
-          if( memcmp(zIn, azChar[i], len)==0 ) break;
+          if( len<=nIn && memcmp(zIn, azChar[i], len)==0 ) break;
         }
         if( i>=nChar ) break;
         zIn += len;
@@ -66810,9 +86262,16 @@ static void trimFunc(
 }
 
 
+/* IMP: R-25361-16150 This function is omitted from SQLite by default. It
+** is only available if the SQLITE_SOUNDEX compile-time option is used
+** when SQLite is built.
+*/
 #ifdef SQLITE_SOUNDEX
 /*
 ** Compute the soundex encoding of a word.
+**
+** IMP: R-59782-00072 The soundex(X) function returns a string that is the
+** soundex encoding of the string X. 
 */
 static void soundexFunc(
   sqlite3_context *context,
@@ -66835,10 +86294,10 @@ static void soundexFunc(
   assert( argc==1 );
   zIn = (u8*)sqlite3_value_text(argv[0]);
   if( zIn==0 ) zIn = (u8*)"";
-  for(i=0; zIn[i] && !isalpha(zIn[i]); i++){}
+  for(i=0; zIn[i] && !sqlite3Isalpha(zIn[i]); i++){}
   if( zIn[i] ){
     u8 prevcode = iCode[zIn[i]&0x7f];
-    zResult[0] = toupper(zIn[i]);
+    zResult[0] = sqlite3Toupper(zIn[i]);
     for(j=1; j<4 && zIn[i]; i++){
       int code = iCode[zIn[i]&0x7f];
       if( code>0 ){
@@ -66856,10 +86315,12 @@ static void soundexFunc(
     zResult[j] = 0;
     sqlite3_result_text(context, zResult, 4, SQLITE_TRANSIENT);
   }else{
+    /* IMP: R-64894-50321 The string "?000" is returned if the argument
+    ** is NULL or contains no ASCII alphabetic characters. */
     sqlite3_result_text(context, "?000", 4, SQLITE_STATIC);
   }
 }
-#endif
+#endif /* SQLITE_SOUNDEX */
 
 #ifndef SQLITE_OMIT_LOAD_EXTENSION
 /*
@@ -66919,13 +86380,8 @@ static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
     if( type==SQLITE_INTEGER ){
       i64 v = sqlite3_value_int64(argv[0]);
       p->rSum += v;
-      if( (p->approx|p->overflow)==0 ){
-        i64 iNewSum = p->iSum + v;
-        int s1 = (int)(p->iSum >> (sizeof(i64)*8-1));
-        int s2 = (int)(v       >> (sizeof(i64)*8-1));
-        int s3 = (int)(iNewSum >> (sizeof(i64)*8-1));
-        p->overflow = ((s1&s2&~s3) | (~s1&~s2&s3))?1:0;
-        p->iSum = iNewSum;
+      if( (p->approx|p->overflow)==0 && sqlite3AddInt64(&p->iSum, v) ){
+        p->overflow = 1;
       }
     }else{
       p->rSum += sqlite3_value_double(argv[0]);
@@ -66956,7 +86412,8 @@ static void avgFinalize(sqlite3_context *context){
 static void totalFinalize(sqlite3_context *context){
   SumCtx *p;
   p = sqlite3_aggregate_context(context, 0);
-  sqlite3_result_double(context, p ? p->rSum : 0.0);
+  /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+  sqlite3_result_double(context, p ? p->rSum : (double)0);
 }
 
 /*
@@ -66977,6 +86434,15 @@ static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
   if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0])) && p ){
     p->n++;
   }
+
+#ifndef SQLITE_OMIT_DEPRECATED
+  /* The sqlite3_aggregate_count() function is deprecated.  But just to make
+  ** sure it still operates correctly, verify that its count agrees with our 
+  ** internal count when using count(*) and when the total count can be
+  ** expressed as a 32-bit integer. */
+  assert( argc==1 || p==0 || p->n>0x7fffffff
+          || p->n==sqlite3_aggregate_count(context) );
+#endif
 }   
 static void countFinalize(sqlite3_context *context){
   CountCtx *p;
@@ -66996,11 +86462,12 @@ static void minmaxStep(
   Mem *pBest;
   UNUSED_PARAMETER(NotUsed);
 
-  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
   pBest = (Mem *)sqlite3_aggregate_context(context, sizeof(*pBest));
   if( !pBest ) return;
 
-  if( pBest->flags ){
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
+    if( pBest->flags ) sqlite3SkipAccumulatorLoad(context);
+  }else if( pBest->flags ){
     int max;
     int cmp;
     CollSeq *pColl = sqlite3GetFuncCollSeq(context);
@@ -67016,6 +86483,8 @@ static void minmaxStep(
     cmp = sqlite3MemCompare(pBest, pArg, pColl);
     if( (max && cmp<0) || (!max && cmp>0) ){
       sqlite3VdbeMemCopy(pBest, pArg);
+    }else{
+      sqlite3SkipAccumulatorLoad(context);
     }
   }else{
     sqlite3VdbeMemCopy(pBest, pArg);
@@ -67043,31 +86512,29 @@ static void groupConcatStep(
   const char *zVal;
   StrAccum *pAccum;
   const char *zSep;
-  int nVal, nSep, i;
-  if( argc==0 || sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  int nVal, nSep;
+  assert( argc==1 || argc==2 );
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
   pAccum = (StrAccum*)sqlite3_aggregate_context(context, sizeof(*pAccum));
 
   if( pAccum ){
     sqlite3 *db = sqlite3_context_db_handle(context);
-    pAccum->useMalloc = 1;
+    int firstTerm = pAccum->useMalloc==0;
+    pAccum->useMalloc = 2;
     pAccum->mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
-    if( pAccum->nChar ){
-      if( argc>1 ){
-        zSep = (char*)sqlite3_value_text(argv[argc-1]);
-        nSep = sqlite3_value_bytes(argv[argc-1]);
+    if( !firstTerm ){
+      if( argc==2 ){
+        zSep = (char*)sqlite3_value_text(argv[1]);
+        nSep = sqlite3_value_bytes(argv[1]);
       }else{
         zSep = ",";
         nSep = 1;
       }
       sqlite3StrAccumAppend(pAccum, zSep, nSep);
     }
-    i = 0;
-    do{
-      zVal = (char*)sqlite3_value_text(argv[i]);
-      nVal = sqlite3_value_bytes(argv[i]);
-      sqlite3StrAccumAppend(pAccum, zVal, nVal);
-      i++;
-    }while( i<argc-1 );
+    zVal = (char*)sqlite3_value_text(argv[0]);
+    nVal = sqlite3_value_bytes(argv[0]);
+    sqlite3StrAccumAppend(pAccum, zVal, nVal);
   }
 }
 static void groupConcatFinalize(sqlite3_context *context){
@@ -67086,24 +86553,16 @@ static void groupConcatFinalize(sqlite3_context *context){
 }
 
 /*
-** This function registered all of the above C functions as SQL
-** functions.  This should be the only routine in this file with
-** external linkage.
+** This routine does per-connection function registration.  Most
+** of the built-in functions above are part of the global function set.
+** This routine only deals with those that are not global.
 */
 SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(sqlite3 *db){
-#ifndef SQLITE_OMIT_ALTERTABLE
-  sqlite3AlterFunctions(db);
-#endif
-  if( !db->mallocFailed ){
-    int rc = sqlite3_overload_function(db, "MATCH", 2);
-    assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
-    if( rc==SQLITE_NOMEM ){
-      db->mallocFailed = 1;
-    }
+  int rc = sqlite3_overload_function(db, "MATCH", 2);
+  assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
+  if( rc==SQLITE_NOMEM ){
+    db->mallocFailed = 1;
   }
-#ifdef SQLITE_SSE
-  (void)sqlite3SseFunctions(db);
-#endif
 }
 
 /*
@@ -67113,7 +86572,7 @@ static void setLikeOptFlag(sqlite3 *db, const char *zName, u8 flagVal){
   FuncDef *pDef;
   pDef = sqlite3FindFunction(db, zName, sqlite3Strlen30(zName),
                              2, SQLITE_UTF8, 0);
-  if( pDef ){
+  if( ALWAYS(pDef) ){
     pDef->flags = flagVal;
   }
 }
@@ -67130,10 +86589,10 @@ SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3 *db, int caseSensitive)
   }else{
     pInfo = (struct compareInfo*)&likeInfoNorm;
   }
-  sqlite3CreateFunc(db, "like", 2, SQLITE_UTF8, pInfo, likeFunc, 0, 0);
-  sqlite3CreateFunc(db, "like", 3, SQLITE_UTF8, pInfo, likeFunc, 0, 0);
+  sqlite3CreateFunc(db, "like", 2, SQLITE_UTF8, pInfo, likeFunc, 0, 0, 0);
+  sqlite3CreateFunc(db, "like", 3, SQLITE_UTF8, pInfo, likeFunc, 0, 0, 0);
   sqlite3CreateFunc(db, "glob", 2, SQLITE_UTF8, 
-      (struct compareInfo*)&globInfo, likeFunc, 0,0);
+      (struct compareInfo*)&globInfo, likeFunc, 0, 0, 0);
   setLikeOptFlag(db, "glob", SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE);
   setLikeOptFlag(db, "like", 
       caseSensitive ? (SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE) : SQLITE_FUNC_LIKE);
@@ -67148,15 +86607,17 @@ SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3 *db, int caseSensitive)
 */
 SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3 *db, Expr *pExpr, int *pIsNocase, char *aWc){
   FuncDef *pDef;
-  if( pExpr->op!=TK_FUNCTION || !pExpr->pList ){
+  if( pExpr->op!=TK_FUNCTION 
+   || !pExpr->x.pList 
+   || pExpr->x.pList->nExpr!=2
+  ){
     return 0;
   }
-  if( pExpr->pList->nExpr!=2 ){
-    return 0;
-  }
-  pDef = sqlite3FindFunction(db, (char*)pExpr->token.z, pExpr->token.n, 2,
-                             SQLITE_UTF8, 0);
-  if( pDef==0 || (pDef->flags & SQLITE_FUNC_LIKE)==0 ){
+  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, 
+                             sqlite3Strlen30(pExpr->u.zToken),
+                             2, SQLITE_UTF8, 0);
+  if( NEVER(pDef==0) || (pDef->flags & SQLITE_FUNC_LIKE)==0 ){
     return 0;
   }
 
@@ -67201,24 +86662,32 @@ SQLITE_PRIVATE void sqlite3RegisterGlobalFunctions(void){
     FUNCTION(max,               -1, 1, 1, minmaxFunc       ),
     FUNCTION(max,                0, 1, 1, 0                ),
     AGGREGATE(max,               1, 1, 1, minmaxStep,      minMaxFinalize ),
-    FUNCTION(typeof,             1, 0, 0, typeofFunc       ),
-    FUNCTION(length,             1, 0, 0, lengthFunc       ),
+    FUNCTION2(typeof,            1, 0, 0, typeofFunc,  SQLITE_FUNC_TYPEOF),
+    FUNCTION2(length,            1, 0, 0, lengthFunc,  SQLITE_FUNC_LENGTH),
     FUNCTION(substr,             2, 0, 0, substrFunc       ),
     FUNCTION(substr,             3, 0, 0, substrFunc       ),
     FUNCTION(abs,                1, 0, 0, absFunc          ),
+#ifndef SQLITE_OMIT_FLOATING_POINT
     FUNCTION(round,              1, 0, 0, roundFunc        ),
     FUNCTION(round,              2, 0, 0, roundFunc        ),
+#endif
     FUNCTION(upper,              1, 0, 0, upperFunc        ),
     FUNCTION(lower,              1, 0, 0, lowerFunc        ),
     FUNCTION(coalesce,           1, 0, 0, 0                ),
-    FUNCTION(coalesce,          -1, 0, 0, ifnullFunc       ),
     FUNCTION(coalesce,           0, 0, 0, 0                ),
+    FUNCTION2(coalesce,         -1, 0, 0, ifnullFunc,  SQLITE_FUNC_COALESCE),
     FUNCTION(hex,                1, 0, 0, hexFunc          ),
-    FUNCTION(ifnull,             2, 0, 1, ifnullFunc       ),
-    FUNCTION(random,            -1, 0, 0, randomFunc       ),
+    FUNCTION2(ifnull,            2, 0, 0, ifnullFunc,  SQLITE_FUNC_COALESCE),
+    FUNCTION(random,             0, 0, 0, randomFunc       ),
     FUNCTION(randomblob,         1, 0, 0, randomBlob       ),
     FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
     FUNCTION(sqlite_version,     0, 0, 0, versionFunc      ),
+    FUNCTION(sqlite_source_id,   0, 0, 0, sourceidFunc     ),
+    FUNCTION(sqlite_log,         2, 0, 0, errlogFunc       ),
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+    FUNCTION(sqlite_compileoption_used,1, 0, 0, compileoptionusedFunc  ),
+    FUNCTION(sqlite_compileoption_get, 1, 0, 0, compileoptiongetFunc  ),
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
     FUNCTION(quote,              1, 0, 0, quoteFunc        ),
     FUNCTION(last_insert_rowid,  0, 0, 0, last_insert_rowid),
     FUNCTION(changes,            0, 0, 0, changes          ),
@@ -67235,9 +86704,11 @@ SQLITE_PRIVATE void sqlite3RegisterGlobalFunctions(void){
     AGGREGATE(sum,               1, 0, 0, sumStep,         sumFinalize    ),
     AGGREGATE(total,             1, 0, 0, sumStep,         totalFinalize    ),
     AGGREGATE(avg,               1, 0, 0, sumStep,         avgFinalize    ),
-    AGGREGATE(count,             0, 0, 0, countStep,       countFinalize  ),
+ /* AGGREGATE(count,             0, 0, 0, countStep,       countFinalize  ), */
+    {0,SQLITE_UTF8,SQLITE_FUNC_COUNT,0,0,0,countStep,countFinalize,"count",0,0},
     AGGREGATE(count,             1, 0, 0, countStep,       countFinalize  ),
-    AGGREGATE(group_concat,     -1, 0, 0, groupConcatStep, groupConcatFinalize),
+    AGGREGATE(group_concat,      1, 0, 0, groupConcatStep, groupConcatFinalize),
+    AGGREGATE(group_concat,      2, 0, 0, groupConcatStep, groupConcatFinalize),
   
     LIKEFUNC(glob, 2, &globInfo, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
   #ifdef SQLITE_CASE_SENSITIVE_LIKE
@@ -67257,9 +86728,1233 @@ SQLITE_PRIVATE void sqlite3RegisterGlobalFunctions(void){
     sqlite3FuncDefInsert(pHash, &aFunc[i]);
   }
   sqlite3RegisterDateTimeFunctions();
+#ifndef SQLITE_OMIT_ALTERTABLE
+  sqlite3AlterFunctions();
+#endif
 }
 
 /************** End of func.c ************************************************/
+/************** Begin file fkey.c ********************************************/
+/*
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used by the compiler to add foreign key
+** support to compiled SQL statements.
+*/
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+#ifndef SQLITE_OMIT_TRIGGER
+
+/*
+** Deferred and Immediate FKs
+** --------------------------
+**
+** Foreign keys in SQLite come in two flavours: deferred and immediate.
+** If an immediate foreign key constraint is violated, SQLITE_CONSTRAINT
+** is returned and the current statement transaction rolled back. If a 
+** deferred foreign key constraint is violated, no action is taken 
+** immediately. However if the application attempts to commit the 
+** transaction before fixing the constraint violation, the attempt fails.
+**
+** Deferred constraints are implemented using a simple counter associated
+** with the database handle. The counter is set to zero each time a 
+** database transaction is opened. Each time a statement is executed 
+** that causes a foreign key violation, the counter is incremented. Each
+** time a statement is executed that removes an existing violation from
+** the database, the counter is decremented. When the transaction is
+** committed, the commit fails if the current value of the counter is
+** greater than zero. This scheme has two big drawbacks:
+**
+**   * When a commit fails due to a deferred foreign key constraint, 
+**     there is no way to tell which foreign constraint is not satisfied,
+**     or which row it is not satisfied for.
+**
+**   * If the database contains foreign key violations when the 
+**     transaction is opened, this may cause the mechanism to malfunction.
+**
+** Despite these problems, this approach is adopted as it seems simpler
+** than the alternatives.
+**
+** INSERT operations:
+**
+**   I.1) For each FK for which the table is the child table, search
+**        the parent table for a match. If none is found increment the
+**        constraint counter.
+**
+**   I.2) For each FK for which the table is the parent table, 
+**        search the child table for rows that correspond to the new
+**        row in the parent table. Decrement the counter for each row
+**        found (as the constraint is now satisfied).
+**
+** DELETE operations:
+**
+**   D.1) For each FK for which the table is the child table, 
+**        search the parent table for a row that corresponds to the 
+**        deleted row in the child table. If such a row is not found, 
+**        decrement the counter.
+**
+**   D.2) For each FK for which the table is the parent table, search 
+**        the child table for rows that correspond to the deleted row 
+**        in the parent table. For each found increment the counter.
+**
+** UPDATE operations:
+**
+**   An UPDATE command requires that all 4 steps above are taken, but only
+**   for FK constraints for which the affected columns are actually 
+**   modified (values must be compared at runtime).
+**
+** Note that I.1 and D.1 are very similar operations, as are I.2 and D.2.
+** This simplifies the implementation a bit.
+**
+** For the purposes of immediate FK constraints, the OR REPLACE conflict
+** resolution is considered to delete rows before the new row is inserted.
+** If a delete caused by OR REPLACE violates an FK constraint, an exception
+** is thrown, even if the FK constraint would be satisfied after the new 
+** row is inserted.
+**
+** Immediate constraints are usually handled similarly. The only difference 
+** is that the counter used is stored as part of each individual statement
+** object (struct Vdbe). If, after the statement has run, its immediate
+** constraint counter is greater than zero, it returns SQLITE_CONSTRAINT
+** and the statement transaction is rolled back. An exception is an INSERT
+** statement that inserts a single row only (no triggers). In this case,
+** instead of using a counter, an exception is thrown immediately if the
+** INSERT violates a foreign key constraint. This is necessary as such
+** an INSERT does not open a statement transaction.
+**
+** TODO: How should dropping a table be handled? How should renaming a 
+** table be handled?
+**
+**
+** Query API Notes
+** ---------------
+**
+** Before coding an UPDATE or DELETE row operation, the code-generator
+** for those two operations needs to know whether or not the operation
+** requires any FK processing and, if so, which columns of the original
+** row are required by the FK processing VDBE code (i.e. if FKs were
+** implemented using triggers, which of the old.* columns would be 
+** accessed). No information is required by the code-generator before
+** coding an INSERT operation. The functions used by the UPDATE/DELETE
+** generation code to query for this information are:
+**
+**   sqlite3FkRequired() - Test to see if FK processing is required.
+**   sqlite3FkOldmask()  - Query for the set of required old.* columns.
+**
+**
+** Externally accessible module functions
+** --------------------------------------
+**
+**   sqlite3FkCheck()    - Check for foreign key violations.
+**   sqlite3FkActions()  - Code triggers for ON UPDATE/ON DELETE actions.
+**   sqlite3FkDelete()   - Delete an FKey structure.
+*/
+
+/*
+** VDBE Calling Convention
+** -----------------------
+**
+** Example:
+**
+**   For the following INSERT statement:
+**
+**     CREATE TABLE t1(a, b INTEGER PRIMARY KEY, c);
+**     INSERT INTO t1 VALUES(1, 2, 3.1);
+**
+**   Register (x):        2    (type integer)
+**   Register (x+1):      1    (type integer)
+**   Register (x+2):      NULL (type NULL)
+**   Register (x+3):      3.1  (type real)
+*/
+
+/*
+** A foreign key constraint requires that the key columns in the parent
+** table are collectively subject to a UNIQUE or PRIMARY KEY constraint.
+** Given that pParent is the parent table for foreign key constraint pFKey, 
+** search the schema a unique index on the parent key columns. 
+**
+** If successful, zero is returned. If the parent key is an INTEGER PRIMARY 
+** KEY column, then output variable *ppIdx is set to NULL. Otherwise, *ppIdx 
+** is set to point to the unique index. 
+** 
+** If the parent key consists of a single column (the foreign key constraint
+** is not a composite foreign key), output variable *paiCol is set to NULL.
+** Otherwise, it is set to point to an allocated array of size N, where
+** N is the number of columns in the parent key. The first element of the
+** array is the index of the child table column that is mapped by the FK
+** constraint to the parent table column stored in the left-most column
+** of index *ppIdx. The second element of the array is the index of the
+** child table column that corresponds to the second left-most column of
+** *ppIdx, and so on.
+**
+** If the required index cannot be found, either because:
+**
+**   1) The named parent key columns do not exist, or
+**
+**   2) The named parent key columns do exist, but are not subject to a
+**      UNIQUE or PRIMARY KEY constraint, or
+**
+**   3) No parent key columns were provided explicitly as part of the
+**      foreign key definition, and the parent table does not have a
+**      PRIMARY KEY, or
+**
+**   4) No parent key columns were provided explicitly as part of the
+**      foreign key definition, and the PRIMARY KEY of the parent table 
+**      consists of a a different number of columns to the child key in 
+**      the child table.
+**
+** then non-zero is returned, and a "foreign key mismatch" error loaded
+** into pParse. If an OOM error occurs, non-zero is returned and the
+** pParse->db->mallocFailed flag is set.
+*/
+static int locateFkeyIndex(
+  Parse *pParse,                  /* Parse context to store any error in */
+  Table *pParent,                 /* Parent table of FK constraint pFKey */
+  FKey *pFKey,                    /* Foreign key to find index for */
+  Index **ppIdx,                  /* OUT: Unique index on parent table */
+  int **paiCol                    /* OUT: Map of index columns in pFKey */
+){
+  Index *pIdx = 0;                    /* Value to return via *ppIdx */
+  int *aiCol = 0;                     /* Value to return via *paiCol */
+  int nCol = pFKey->nCol;             /* Number of columns in parent key */
+  char *zKey = pFKey->aCol[0].zCol;   /* Name of left-most parent key column */
+
+  /* The caller is responsible for zeroing output parameters. */
+  assert( ppIdx && *ppIdx==0 );
+  assert( !paiCol || *paiCol==0 );
+  assert( pParse );
+
+  /* If this is a non-composite (single column) foreign key, check if it 
+  ** maps to the INTEGER PRIMARY KEY of table pParent. If so, leave *ppIdx 
+  ** and *paiCol set to zero and return early. 
+  **
+  ** Otherwise, for a composite foreign key (more than one column), allocate
+  ** space for the aiCol array (returned via output parameter *paiCol).
+  ** Non-composite foreign keys do not require the aiCol array.
+  */
+  if( nCol==1 ){
+    /* The FK maps to the IPK if any of the following are true:
+    **
+    **   1) There is an INTEGER PRIMARY KEY column and the FK is implicitly 
+    **      mapped to the primary key of table pParent, or
+    **   2) The FK is explicitly mapped to a column declared as INTEGER
+    **      PRIMARY KEY.
+    */
+    if( pParent->iPKey>=0 ){
+      if( !zKey ) return 0;
+      if( !sqlite3StrICmp(pParent->aCol[pParent->iPKey].zName, zKey) ) return 0;
+    }
+  }else if( paiCol ){
+    assert( nCol>1 );
+    aiCol = (int *)sqlite3DbMallocRaw(pParse->db, nCol*sizeof(int));
+    if( !aiCol ) return 1;
+    *paiCol = aiCol;
+  }
+
+  for(pIdx=pParent->pIndex; pIdx; pIdx=pIdx->pNext){
+    if( pIdx->nColumn==nCol && pIdx->onError!=OE_None ){ 
+      /* pIdx is a UNIQUE index (or a PRIMARY KEY) and has the right number
+      ** of columns. If each indexed column corresponds to a foreign key
+      ** column of pFKey, then this index is a winner.  */
+
+      if( zKey==0 ){
+        /* If zKey is NULL, then this foreign key is implicitly mapped to 
+        ** the PRIMARY KEY of table pParent. The PRIMARY KEY index may be 
+        ** identified by the test (Index.autoIndex==2).  */
+        if( pIdx->autoIndex==2 ){
+          if( aiCol ){
+            int i;
+            for(i=0; i<nCol; i++) aiCol[i] = pFKey->aCol[i].iFrom;
+          }
+          break;
+        }
+      }else{
+        /* If zKey is non-NULL, then this foreign key was declared to
+        ** map to an explicit list of columns in table pParent. Check if this
+        ** index matches those columns. Also, check that the index uses
+        ** the default collation sequences for each column. */
+        int i, j;
+        for(i=0; i<nCol; i++){
+          int iCol = pIdx->aiColumn[i];     /* Index of column in parent tbl */
+          char *zDfltColl;                  /* Def. collation for column */
+          char *zIdxCol;                    /* Name of indexed column */
+
+          /* If the index uses a collation sequence that is different from
+          ** the default collation sequence for the column, this index is
+          ** unusable. Bail out early in this case.  */
+          zDfltColl = pParent->aCol[iCol].zColl;
+          if( !zDfltColl ){
+            zDfltColl = "BINARY";
+          }
+          if( sqlite3StrICmp(pIdx->azColl[i], zDfltColl) ) break;
+
+          zIdxCol = pParent->aCol[iCol].zName;
+          for(j=0; j<nCol; j++){
+            if( sqlite3StrICmp(pFKey->aCol[j].zCol, zIdxCol)==0 ){
+              if( aiCol ) aiCol[i] = pFKey->aCol[j].iFrom;
+              break;
+            }
+          }
+          if( j==nCol ) break;
+        }
+        if( i==nCol ) break;      /* pIdx is usable */
+      }
+    }
+  }
+
+  if( !pIdx ){
+    if( !pParse->disableTriggers ){
+      sqlite3ErrorMsg(pParse, "foreign key mismatch");
+    }
+    sqlite3DbFree(pParse->db, aiCol);
+    return 1;
+  }
+
+  *ppIdx = pIdx;
+  return 0;
+}
+
+/*
+** This function is called when a row is inserted into or deleted from the 
+** child table of foreign key constraint pFKey. If an SQL UPDATE is executed 
+** on the child table of pFKey, this function is invoked twice for each row
+** affected - once to "delete" the old row, and then again to "insert" the
+** new row.
+**
+** Each time it is called, this function generates VDBE code to locate the
+** row in the parent table that corresponds to the row being inserted into 
+** or deleted from the child table. If the parent row can be found, no 
+** special action is taken. Otherwise, if the parent row can *not* be
+** found in the parent table:
+**
+**   Operation | FK type   | Action taken
+**   --------------------------------------------------------------------------
+**   INSERT      immediate   Increment the "immediate constraint counter".
+**
+**   DELETE      immediate   Decrement the "immediate constraint counter".
+**
+**   INSERT      deferred    Increment the "deferred constraint counter".
+**
+**   DELETE      deferred    Decrement the "deferred constraint counter".
+**
+** These operations are identified in the comment at the top of this file 
+** (fkey.c) as "I.1" and "D.1".
+*/
+static void fkLookupParent(
+  Parse *pParse,        /* Parse context */
+  int iDb,              /* Index of database housing pTab */
+  Table *pTab,          /* Parent table of FK pFKey */
+  Index *pIdx,          /* Unique index on parent key columns in pTab */
+  FKey *pFKey,          /* Foreign key constraint */
+  int *aiCol,           /* Map from parent key columns to child table columns */
+  int regData,          /* Address of array containing child table row */
+  int nIncr,            /* Increment constraint counter by this */
+  int isIgnore          /* If true, pretend pTab contains all NULL values */
+){
+  int i;                                    /* Iterator variable */
+  Vdbe *v = sqlite3GetVdbe(pParse);         /* Vdbe to add code to */
+  int iCur = pParse->nTab - 1;              /* Cursor number to use */
+  int iOk = sqlite3VdbeMakeLabel(v);        /* jump here if parent key found */
+
+  /* If nIncr is less than zero, then check at runtime if there are any
+  ** outstanding constraints to resolve. If there are not, there is no need
+  ** to check if deleting this row resolves any outstanding violations.
+  **
+  ** Check if any of the key columns in the child table row are NULL. If 
+  ** any are, then the constraint is considered satisfied. No need to 
+  ** search for a matching row in the parent table.  */
+  if( nIncr<0 ){
+    sqlite3VdbeAddOp2(v, OP_FkIfZero, pFKey->isDeferred, iOk);
+  }
+  for(i=0; i<pFKey->nCol; i++){
+    int iReg = aiCol[i] + regData + 1;
+    sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iOk);
+  }
+
+  if( isIgnore==0 ){
+    if( pIdx==0 ){
+      /* If pIdx is NULL, then the parent key is the INTEGER PRIMARY KEY
+      ** column of the parent table (table pTab).  */
+      int iMustBeInt;               /* Address of MustBeInt instruction */
+      int regTemp = sqlite3GetTempReg(pParse);
+  
+      /* Invoke MustBeInt to coerce the child key value to an integer (i.e. 
+      ** apply the affinity of the parent key). If this fails, then there
+      ** is no matching parent key. Before using MustBeInt, make a copy of
+      ** the value. Otherwise, the value inserted into the child key column
+      ** will have INTEGER affinity applied to it, which may not be correct.  */
+      sqlite3VdbeAddOp2(v, OP_SCopy, aiCol[0]+1+regData, regTemp);
+      iMustBeInt = sqlite3VdbeAddOp2(v, OP_MustBeInt, regTemp, 0);
+  
+      /* If the parent table is the same as the child table, and we are about
+      ** to increment the constraint-counter (i.e. this is an INSERT operation),
+      ** then check if the row being inserted matches itself. If so, do not
+      ** increment the constraint-counter.  */
+      if( pTab==pFKey->pFrom && nIncr==1 ){
+        sqlite3VdbeAddOp3(v, OP_Eq, regData, iOk, regTemp);
+      }
+  
+      sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
+      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regTemp);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, iOk);
+      sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
+      sqlite3VdbeJumpHere(v, iMustBeInt);
+      sqlite3ReleaseTempReg(pParse, regTemp);
+    }else{
+      int nCol = pFKey->nCol;
+      int regTemp = sqlite3GetTempRange(pParse, nCol);
+      int regRec = sqlite3GetTempReg(pParse);
+      KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
+  
+      sqlite3VdbeAddOp3(v, OP_OpenRead, iCur, pIdx->tnum, iDb);
+      sqlite3VdbeChangeP4(v, -1, (char*)pKey, P4_KEYINFO_HANDOFF);
+      for(i=0; i<nCol; i++){
+        sqlite3VdbeAddOp2(v, OP_Copy, aiCol[i]+1+regData, regTemp+i);
+      }
+  
+      /* If the parent table is the same as the child table, and we are about
+      ** to increment the constraint-counter (i.e. this is an INSERT operation),
+      ** then check if the row being inserted matches itself. If so, do not
+      ** increment the constraint-counter. 
+      **
+      ** If any of the parent-key values are NULL, then the row cannot match 
+      ** itself. So set JUMPIFNULL to make sure we do the OP_Found if any
+      ** of the parent-key values are NULL (at this point it is known that
+      ** none of the child key values are).
+      */
+      if( pTab==pFKey->pFrom && nIncr==1 ){
+        int iJump = sqlite3VdbeCurrentAddr(v) + nCol + 1;
+        for(i=0; i<nCol; i++){
+          int iChild = aiCol[i]+1+regData;
+          int iParent = pIdx->aiColumn[i]+1+regData;
+          assert( aiCol[i]!=pTab->iPKey );
+          if( pIdx->aiColumn[i]==pTab->iPKey ){
+            /* The parent key is a composite key that includes the IPK column */
+            iParent = regData;
+          }
+          sqlite3VdbeAddOp3(v, OP_Ne, iChild, iJump, iParent);
+          sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
+        }
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, iOk);
+      }
+  
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regTemp, nCol, regRec);
+      sqlite3VdbeChangeP4(v, -1, sqlite3IndexAffinityStr(v,pIdx), P4_TRANSIENT);
+      sqlite3VdbeAddOp4Int(v, OP_Found, iCur, iOk, regRec, 0);
+  
+      sqlite3ReleaseTempReg(pParse, regRec);
+      sqlite3ReleaseTempRange(pParse, regTemp, nCol);
+    }
+  }
+
+  if( !pFKey->isDeferred && !pParse->pToplevel && !pParse->isMultiWrite ){
+    /* Special case: If this is an INSERT statement that will insert exactly
+    ** one row into the table, raise a constraint immediately instead of
+    ** incrementing a counter. This is necessary as the VM code is being
+    ** generated for will not open a statement transaction.  */
+    assert( nIncr==1 );
+    sqlite3HaltConstraint(
+        pParse, OE_Abort, "foreign key constraint failed", P4_STATIC
+    );
+  }else{
+    if( nIncr>0 && pFKey->isDeferred==0 ){
+      sqlite3ParseToplevel(pParse)->mayAbort = 1;
+    }
+    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
+  }
+
+  sqlite3VdbeResolveLabel(v, iOk);
+  sqlite3VdbeAddOp1(v, OP_Close, iCur);
+}
+
+/*
+** This function is called to generate code executed when a row is deleted
+** from the parent table of foreign key constraint pFKey and, if pFKey is 
+** deferred, when a row is inserted into the same table. When generating
+** code for an SQL UPDATE operation, this function may be called twice -
+** once to "delete" the old row and once to "insert" the new row.
+**
+** The code generated by this function scans through the rows in the child
+** table that correspond to the parent table row being deleted or inserted.
+** For each child row found, one of the following actions is taken:
+**
+**   Operation | FK type   | Action taken
+**   --------------------------------------------------------------------------
+**   DELETE      immediate   Increment the "immediate constraint counter".
+**                           Or, if the ON (UPDATE|DELETE) action is RESTRICT,
+**                           throw a "foreign key constraint failed" exception.
+**
+**   INSERT      immediate   Decrement the "immediate constraint counter".
+**
+**   DELETE      deferred    Increment the "deferred constraint counter".
+**                           Or, if the ON (UPDATE|DELETE) action is RESTRICT,
+**                           throw a "foreign key constraint failed" exception.
+**
+**   INSERT      deferred    Decrement the "deferred constraint counter".
+**
+** These operations are identified in the comment at the top of this file 
+** (fkey.c) as "I.2" and "D.2".
+*/
+static void fkScanChildren(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pSrc,                  /* SrcList containing the table to scan */
+  Table *pTab,
+  Index *pIdx,                    /* Foreign key index */
+  FKey *pFKey,                    /* Foreign key relationship */
+  int *aiCol,                     /* Map from pIdx cols to child table cols */
+  int regData,                    /* Referenced table data starts here */
+  int nIncr                       /* Amount to increment deferred counter by */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  int i;                          /* Iterator variable */
+  Expr *pWhere = 0;               /* WHERE clause to scan with */
+  NameContext sNameContext;       /* Context used to resolve WHERE clause */
+  WhereInfo *pWInfo;              /* Context used by sqlite3WhereXXX() */
+  int iFkIfZero = 0;              /* Address of OP_FkIfZero */
+  Vdbe *v = sqlite3GetVdbe(pParse);
+
+  assert( !pIdx || pIdx->pTable==pTab );
+
+  if( nIncr<0 ){
+    iFkIfZero = sqlite3VdbeAddOp2(v, OP_FkIfZero, pFKey->isDeferred, 0);
+  }
+
+  /* Create an Expr object representing an SQL expression like:
+  **
+  **   <parent-key1> = <child-key1> AND <parent-key2> = <child-key2> ...
+  **
+  ** The collation sequence used for the comparison should be that of
+  ** the parent key columns. The affinity of the parent key column should
+  ** be applied to each child key value before the comparison takes place.
+  */
+  for(i=0; i<pFKey->nCol; i++){
+    Expr *pLeft;                  /* Value from parent table row */
+    Expr *pRight;                 /* Column ref to child table */
+    Expr *pEq;                    /* Expression (pLeft = pRight) */
+    int iCol;                     /* Index of column in child table */ 
+    const char *zCol;             /* Name of column in child table */
+
+    pLeft = sqlite3Expr(db, TK_REGISTER, 0);
+    if( pLeft ){
+      /* Set the collation sequence and affinity of the LHS of each TK_EQ
+      ** expression to the parent key column defaults.  */
+      if( pIdx ){
+        Column *pCol;
+        iCol = pIdx->aiColumn[i];
+        pCol = &pTab->aCol[iCol];
+        if( pTab->iPKey==iCol ) iCol = -1;
+        pLeft->iTable = regData+iCol+1;
+        pLeft->affinity = pCol->affinity;
+        pLeft->pColl = sqlite3LocateCollSeq(pParse, pCol->zColl);
+      }else{
+        pLeft->iTable = regData;
+        pLeft->affinity = SQLITE_AFF_INTEGER;
+      }
+    }
+    iCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
+    assert( iCol>=0 );
+    zCol = pFKey->pFrom->aCol[iCol].zName;
+    pRight = sqlite3Expr(db, TK_ID, zCol);
+    pEq = sqlite3PExpr(pParse, TK_EQ, pLeft, pRight, 0);
+    pWhere = sqlite3ExprAnd(db, pWhere, pEq);
+  }
+
+  /* If the child table is the same as the parent table, and this scan
+  ** is taking place as part of a DELETE operation (operation D.2), omit the
+  ** row being deleted from the scan by adding ($rowid != rowid) to the WHERE 
+  ** clause, where $rowid is the rowid of the row being deleted.  */
+  if( pTab==pFKey->pFrom && nIncr>0 ){
+    Expr *pEq;                    /* Expression (pLeft = pRight) */
+    Expr *pLeft;                  /* Value from parent table row */
+    Expr *pRight;                 /* Column ref to child table */
+    pLeft = sqlite3Expr(db, TK_REGISTER, 0);
+    pRight = sqlite3Expr(db, TK_COLUMN, 0);
+    if( pLeft && pRight ){
+      pLeft->iTable = regData;
+      pLeft->affinity = SQLITE_AFF_INTEGER;
+      pRight->iTable = pSrc->a[0].iCursor;
+      pRight->iColumn = -1;
+    }
+    pEq = sqlite3PExpr(pParse, TK_NE, pLeft, pRight, 0);
+    pWhere = sqlite3ExprAnd(db, pWhere, pEq);
+  }
+
+  /* Resolve the references in the WHERE clause. */
+  memset(&sNameContext, 0, sizeof(NameContext));
+  sNameContext.pSrcList = pSrc;
+  sNameContext.pParse = pParse;
+  sqlite3ResolveExprNames(&sNameContext, pWhere);
+
+  /* Create VDBE to loop through the entries in pSrc that match the WHERE
+  ** clause. If the constraint is not deferred, throw an exception for
+  ** each row found. Otherwise, for deferred constraints, increment the
+  ** deferred constraint counter by nIncr for each row selected.  */
+  pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
+  if( nIncr>0 && pFKey->isDeferred==0 ){
+    sqlite3ParseToplevel(pParse)->mayAbort = 1;
+  }
+  sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
+  if( pWInfo ){
+    sqlite3WhereEnd(pWInfo);
+  }
+
+  /* Clean up the WHERE clause constructed above. */
+  sqlite3ExprDelete(db, pWhere);
+  if( iFkIfZero ){
+    sqlite3VdbeJumpHere(v, iFkIfZero);
+  }
+}
+
+/*
+** This function returns a pointer to the head of a linked list of FK
+** constraints for which table pTab is the parent table. For example,
+** given the following schema:
+**
+**   CREATE TABLE t1(a PRIMARY KEY);
+**   CREATE TABLE t2(b REFERENCES t1(a);
+**
+** Calling this function with table "t1" as an argument returns a pointer
+** to the FKey structure representing the foreign key constraint on table
+** "t2". Calling this function with "t2" as the argument would return a
+** NULL pointer (as there are no FK constraints for which t2 is the parent
+** table).
+*/
+SQLITE_PRIVATE FKey *sqlite3FkReferences(Table *pTab){
+  int nName = sqlite3Strlen30(pTab->zName);
+  return (FKey *)sqlite3HashFind(&pTab->pSchema->fkeyHash, pTab->zName, nName);
+}
+
+/*
+** The second argument is a Trigger structure allocated by the 
+** fkActionTrigger() routine. This function deletes the Trigger structure
+** and all of its sub-components.
+**
+** The Trigger structure or any of its sub-components may be allocated from
+** the lookaside buffer belonging to database handle dbMem.
+*/
+static void fkTriggerDelete(sqlite3 *dbMem, Trigger *p){
+  if( p ){
+    TriggerStep *pStep = p->step_list;
+    sqlite3ExprDelete(dbMem, pStep->pWhere);
+    sqlite3ExprListDelete(dbMem, pStep->pExprList);
+    sqlite3SelectDelete(dbMem, pStep->pSelect);
+    sqlite3ExprDelete(dbMem, p->pWhen);
+    sqlite3DbFree(dbMem, p);
+  }
+}
+
+/*
+** This function is called to generate code that runs when table pTab is
+** being dropped from the database. The SrcList passed as the second argument
+** to this function contains a single entry guaranteed to resolve to
+** table pTab.
+**
+** Normally, no code is required. However, if either
+**
+**   (a) The table is the parent table of a FK constraint, or
+**   (b) The table is the child table of a deferred FK constraint and it is
+**       determined at runtime that there are outstanding deferred FK 
+**       constraint violations in the database,
+**
+** then the equivalent of "DELETE FROM <tbl>" is executed before dropping
+** the table from the database. Triggers are disabled while running this
+** DELETE, but foreign key actions are not.
+*/
+SQLITE_PRIVATE void sqlite3FkDropTable(Parse *pParse, SrcList *pName, Table *pTab){
+  sqlite3 *db = pParse->db;
+  if( (db->flags&SQLITE_ForeignKeys) && !IsVirtual(pTab) && !pTab->pSelect ){
+    int iSkip = 0;
+    Vdbe *v = sqlite3GetVdbe(pParse);
+
+    assert( v );                  /* VDBE has already been allocated */
+    if( sqlite3FkReferences(pTab)==0 ){
+      /* Search for a deferred foreign key constraint for which this table
+      ** is the child table. If one cannot be found, return without 
+      ** generating any VDBE code. If one can be found, then jump over
+      ** the entire DELETE if there are no outstanding deferred constraints
+      ** when this statement is run.  */
+      FKey *p;
+      for(p=pTab->pFKey; p; p=p->pNextFrom){
+        if( p->isDeferred ) break;
+      }
+      if( !p ) return;
+      iSkip = sqlite3VdbeMakeLabel(v);
+      sqlite3VdbeAddOp2(v, OP_FkIfZero, 1, iSkip);
+    }
+
+    pParse->disableTriggers = 1;
+    sqlite3DeleteFrom(pParse, sqlite3SrcListDup(db, pName, 0), 0);
+    pParse->disableTriggers = 0;
+
+    /* If the DELETE has generated immediate foreign key constraint 
+    ** violations, halt the VDBE and return an error at this point, before
+    ** any modifications to the schema are made. This is because statement
+    ** transactions are not able to rollback schema changes.  */
+    sqlite3VdbeAddOp2(v, OP_FkIfZero, 0, sqlite3VdbeCurrentAddr(v)+2);
+    sqlite3HaltConstraint(
+        pParse, OE_Abort, "foreign key constraint failed", P4_STATIC
+    );
+
+    if( iSkip ){
+      sqlite3VdbeResolveLabel(v, iSkip);
+    }
+  }
+}
+
+/*
+** This function is called when inserting, deleting or updating a row of
+** table pTab to generate VDBE code to perform foreign key constraint 
+** processing for the operation.
+**
+** For a DELETE operation, parameter regOld is passed the index of the
+** first register in an array of (pTab->nCol+1) registers containing the
+** rowid of the row being deleted, followed by each of the column values
+** of the row being deleted, from left to right. Parameter regNew is passed
+** zero in this case.
+**
+** For an INSERT operation, regOld is passed zero and regNew is passed the
+** first register of an array of (pTab->nCol+1) registers containing the new
+** row data.
+**
+** For an UPDATE operation, this function is called twice. Once before
+** the original record is deleted from the table using the calling convention
+** described for DELETE. Then again after the original record is deleted
+** but before the new record is inserted using the INSERT convention. 
+*/
+SQLITE_PRIVATE void sqlite3FkCheck(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Row is being deleted from this table */ 
+  int regOld,                     /* Previous row data is stored here */
+  int regNew                      /* New row data is stored here */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  FKey *pFKey;                    /* Used to iterate through FKs */
+  int iDb;                        /* Index of database containing pTab */
+  const char *zDb;                /* Name of database containing pTab */
+  int isIgnoreErrors = pParse->disableTriggers;
+
+  /* Exactly one of regOld and regNew should be non-zero. */
+  assert( (regOld==0)!=(regNew==0) );
+
+  /* If foreign-keys are disabled, this function is a no-op. */
+  if( (db->flags&SQLITE_ForeignKeys)==0 ) return;
+
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  zDb = db->aDb[iDb].zName;
+
+  /* Loop through all the foreign key constraints for which pTab is the
+  ** child table (the table that the foreign key definition is part of).  */
+  for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
+    Table *pTo;                   /* Parent table of foreign key pFKey */
+    Index *pIdx = 0;              /* Index on key columns in pTo */
+    int *aiFree = 0;
+    int *aiCol;
+    int iCol;
+    int i;
+    int isIgnore = 0;
+
+    /* Find the parent table of this foreign key. Also find a unique index 
+    ** on the parent key columns in the parent table. If either of these 
+    ** schema items cannot be located, set an error in pParse and return 
+    ** early.  */
+    if( pParse->disableTriggers ){
+      pTo = sqlite3FindTable(db, pFKey->zTo, zDb);
+    }else{
+      pTo = sqlite3LocateTable(pParse, 0, pFKey->zTo, zDb);
+    }
+    if( !pTo || locateFkeyIndex(pParse, pTo, pFKey, &pIdx, &aiFree) ){
+      assert( isIgnoreErrors==0 || (regOld!=0 && regNew==0) );
+      if( !isIgnoreErrors || db->mallocFailed ) return;
+      if( pTo==0 ){
+        /* If isIgnoreErrors is true, then a table is being dropped. In this
+        ** case SQLite runs a "DELETE FROM xxx" on the table being dropped
+        ** before actually dropping it in order to check FK constraints.
+        ** If the parent table of an FK constraint on the current table is
+        ** missing, behave as if it is empty. i.e. decrement the relevant
+        ** FK counter for each row of the current table with non-NULL keys.
+        */
+        Vdbe *v = sqlite3GetVdbe(pParse);
+        int iJump = sqlite3VdbeCurrentAddr(v) + pFKey->nCol + 1;
+        for(i=0; i<pFKey->nCol; i++){
+          int iReg = pFKey->aCol[i].iFrom + regOld + 1;
+          sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iJump);
+        }
+        sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, -1);
+      }
+      continue;
+    }
+    assert( pFKey->nCol==1 || (aiFree && pIdx) );
+
+    if( aiFree ){
+      aiCol = aiFree;
+    }else{
+      iCol = pFKey->aCol[0].iFrom;
+      aiCol = &iCol;
+    }
+    for(i=0; i<pFKey->nCol; i++){
+      if( aiCol[i]==pTab->iPKey ){
+        aiCol[i] = -1;
+      }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+      /* Request permission to read the parent key columns. If the 
+      ** authorization callback returns SQLITE_IGNORE, behave as if any
+      ** values read from the parent table are NULL. */
+      if( db->xAuth ){
+        int rcauth;
+        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName;
+        rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
+        isIgnore = (rcauth==SQLITE_IGNORE);
+      }
+#endif
+    }
+
+    /* Take a shared-cache advisory read-lock on the parent table. Allocate 
+    ** a cursor to use to search the unique index on the parent key columns 
+    ** in the parent table.  */
+    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
+    pParse->nTab++;
+
+    if( regOld!=0 ){
+      /* A row is being removed from the child table. Search for the parent.
+      ** If the parent does not exist, removing the child row resolves an 
+      ** outstanding foreign key constraint violation. */
+      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1,isIgnore);
+    }
+    if( regNew!=0 ){
+      /* A row is being added to the child table. If a parent row cannot
+      ** be found, adding the child row has violated the FK constraint. */ 
+      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1,isIgnore);
+    }
+
+    sqlite3DbFree(db, aiFree);
+  }
+
+  /* Loop through all the foreign key constraints that refer to this table */
+  for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
+    Index *pIdx = 0;              /* Foreign key index for pFKey */
+    SrcList *pSrc;
+    int *aiCol = 0;
+
+    if( !pFKey->isDeferred && !pParse->pToplevel && !pParse->isMultiWrite ){
+      assert( regOld==0 && regNew!=0 );
+      /* Inserting a single row into a parent table cannot cause an immediate
+      ** foreign key violation. So do nothing in this case.  */
+      continue;
+    }
+
+    if( locateFkeyIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){
+      if( !isIgnoreErrors || db->mallocFailed ) return;
+      continue;
+    }
+    assert( aiCol || pFKey->nCol==1 );
+
+    /* Create a SrcList structure containing a single table (the table 
+    ** the foreign key that refers to this table is attached to). This
+    ** is required for the sqlite3WhereXXX() interface.  */
+    pSrc = sqlite3SrcListAppend(db, 0, 0, 0);
+    if( pSrc ){
+      struct SrcList_item *pItem = pSrc->a;
+      pItem->pTab = pFKey->pFrom;
+      pItem->zName = pFKey->pFrom->zName;
+      pItem->pTab->nRef++;
+      pItem->iCursor = pParse->nTab++;
+  
+      if( regNew!=0 ){
+        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1);
+      }
+      if( regOld!=0 ){
+        /* If there is a RESTRICT action configured for the current operation
+        ** on the parent table of this FK, then throw an exception 
+        ** immediately if the FK constraint is violated, even if this is a
+        ** deferred trigger. That's what RESTRICT means. To defer checking
+        ** the constraint, the FK should specify NO ACTION (represented
+        ** using OE_None). NO ACTION is the default.  */
+        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1);
+      }
+      pItem->zName = 0;
+      sqlite3SrcListDelete(db, pSrc);
+    }
+    sqlite3DbFree(db, aiCol);
+  }
+}
+
+#define COLUMN_MASK(x) (((x)>31) ? 0xffffffff : ((u32)1<<(x)))
+
+/*
+** This function is called before generating code to update or delete a 
+** row contained in table pTab.
+*/
+SQLITE_PRIVATE u32 sqlite3FkOldmask(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab                     /* Table being modified */
+){
+  u32 mask = 0;
+  if( pParse->db->flags&SQLITE_ForeignKeys ){
+    FKey *p;
+    int i;
+    for(p=pTab->pFKey; p; p=p->pNextFrom){
+      for(i=0; i<p->nCol; i++) mask |= COLUMN_MASK(p->aCol[i].iFrom);
+    }
+    for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+      Index *pIdx = 0;
+      locateFkeyIndex(pParse, pTab, p, &pIdx, 0);
+      if( pIdx ){
+        for(i=0; i<pIdx->nColumn; i++) mask |= COLUMN_MASK(pIdx->aiColumn[i]);
+      }
+    }
+  }
+  return mask;
+}
+
+/*
+** This function is called before generating code to update or delete a 
+** row contained in table pTab. If the operation is a DELETE, then
+** parameter aChange is passed a NULL value. For an UPDATE, aChange points
+** to an array of size N, where N is the number of columns in table pTab.
+** If the i'th column is not modified by the UPDATE, then the corresponding 
+** entry in the aChange[] array is set to -1. If the column is modified,
+** the value is 0 or greater. Parameter chngRowid is set to true if the
+** UPDATE statement modifies the rowid fields of the table.
+**
+** If any foreign key processing will be required, this function returns
+** true. If there is no foreign key related processing, this function 
+** returns false.
+*/
+SQLITE_PRIVATE int sqlite3FkRequired(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being modified */
+  int *aChange,                   /* Non-NULL for UPDATE operations */
+  int chngRowid                   /* True for UPDATE that affects rowid */
+){
+  if( pParse->db->flags&SQLITE_ForeignKeys ){
+    if( !aChange ){
+      /* A DELETE operation. Foreign key processing is required if the 
+      ** table in question is either the child or parent table for any 
+      ** foreign key constraint.  */
+      return (sqlite3FkReferences(pTab) || pTab->pFKey);
+    }else{
+      /* This is an UPDATE. Foreign key processing is only required if the
+      ** operation modifies one or more child or parent key columns. */
+      int i;
+      FKey *p;
+
+      /* Check if any child key columns are being modified. */
+      for(p=pTab->pFKey; p; p=p->pNextFrom){
+        for(i=0; i<p->nCol; i++){
+          int iChildKey = p->aCol[i].iFrom;
+          if( aChange[iChildKey]>=0 ) return 1;
+          if( iChildKey==pTab->iPKey && chngRowid ) return 1;
+        }
+      }
+
+      /* Check if any parent key columns are being modified. */
+      for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+        for(i=0; i<p->nCol; i++){
+          char *zKey = p->aCol[i].zCol;
+          int iKey;
+          for(iKey=0; iKey<pTab->nCol; iKey++){
+            Column *pCol = &pTab->aCol[iKey];
+            if( (zKey ? !sqlite3StrICmp(pCol->zName, zKey) : pCol->isPrimKey) ){
+              if( aChange[iKey]>=0 ) return 1;
+              if( iKey==pTab->iPKey && chngRowid ) return 1;
+            }
+          }
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** This function is called when an UPDATE or DELETE operation is being 
+** compiled on table pTab, which is the parent table of foreign-key pFKey.
+** If the current operation is an UPDATE, then the pChanges parameter is
+** passed a pointer to the list of columns being modified. If it is a
+** DELETE, pChanges is passed a NULL pointer.
+**
+** It returns a pointer to a Trigger structure containing a trigger
+** equivalent to the ON UPDATE or ON DELETE action specified by pFKey.
+** If the action is "NO ACTION" or "RESTRICT", then a NULL pointer is
+** returned (these actions require no special handling by the triggers
+** sub-system, code for them is created by fkScanChildren()).
+**
+** For example, if pFKey is the foreign key and pTab is table "p" in 
+** the following schema:
+**
+**   CREATE TABLE p(pk PRIMARY KEY);
+**   CREATE TABLE c(ck REFERENCES p ON DELETE CASCADE);
+**
+** then the returned trigger structure is equivalent to:
+**
+**   CREATE TRIGGER ... DELETE ON p BEGIN
+**     DELETE FROM c WHERE ck = old.pk;
+**   END;
+**
+** The returned pointer is cached as part of the foreign key object. It
+** is eventually freed along with the rest of the foreign key object by 
+** sqlite3FkDelete().
+*/
+static Trigger *fkActionTrigger(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated or deleted from */
+  FKey *pFKey,                    /* Foreign key to get action for */
+  ExprList *pChanges              /* Change-list for UPDATE, NULL for DELETE */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  int action;                     /* One of OE_None, OE_Cascade etc. */
+  Trigger *pTrigger;              /* Trigger definition to return */
+  int iAction = (pChanges!=0);    /* 1 for UPDATE, 0 for DELETE */
+
+  action = pFKey->aAction[iAction];
+  pTrigger = pFKey->apTrigger[iAction];
+
+  if( action!=OE_None && !pTrigger ){
+    u8 enableLookaside;           /* Copy of db->lookaside.bEnabled */
+    char const *zFrom;            /* Name of child table */
+    int nFrom;                    /* Length in bytes of zFrom */
+    Index *pIdx = 0;              /* Parent key index for this FK */
+    int *aiCol = 0;               /* child table cols -> parent key cols */
+    TriggerStep *pStep = 0;        /* First (only) step of trigger program */
+    Expr *pWhere = 0;             /* WHERE clause of trigger step */
+    ExprList *pList = 0;          /* Changes list if ON UPDATE CASCADE */
+    Select *pSelect = 0;          /* If RESTRICT, "SELECT RAISE(...)" */
+    int i;                        /* Iterator variable */
+    Expr *pWhen = 0;              /* WHEN clause for the trigger */
+
+    if( locateFkeyIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ) return 0;
+    assert( aiCol || pFKey->nCol==1 );
+
+    for(i=0; i<pFKey->nCol; i++){
+      Token tOld = { "old", 3 };  /* Literal "old" token */
+      Token tNew = { "new", 3 };  /* Literal "new" token */
+      Token tFromCol;             /* Name of column in child table */
+      Token tToCol;               /* Name of column in parent table */
+      int iFromCol;               /* Idx of column in child table */
+      Expr *pEq;                  /* tFromCol = OLD.tToCol */
+
+      iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
+      assert( iFromCol>=0 );
+      tToCol.z = pIdx ? pTab->aCol[pIdx->aiColumn[i]].zName : "oid";
+      tFromCol.z = pFKey->pFrom->aCol[iFromCol].zName;
+
+      tToCol.n = sqlite3Strlen30(tToCol.z);
+      tFromCol.n = sqlite3Strlen30(tFromCol.z);
+
+      /* Create the expression "OLD.zToCol = zFromCol". It is important
+      ** that the "OLD.zToCol" term is on the LHS of the = operator, so
+      ** that the affinity and collation sequence associated with the
+      ** parent table are used for the comparison. */
+      pEq = sqlite3PExpr(pParse, TK_EQ,
+          sqlite3PExpr(pParse, TK_DOT, 
+            sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld),
+            sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol)
+          , 0),
+          sqlite3PExpr(pParse, TK_ID, 0, 0, &tFromCol)
+      , 0);
+      pWhere = sqlite3ExprAnd(db, pWhere, pEq);
+
+      /* For ON UPDATE, construct the next term of the WHEN clause.
+      ** The final WHEN clause will be like this:
+      **
+      **    WHEN NOT(old.col1 IS new.col1 AND ... AND old.colN IS new.colN)
+      */
+      if( pChanges ){
+        pEq = sqlite3PExpr(pParse, TK_IS,
+            sqlite3PExpr(pParse, TK_DOT, 
+              sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld),
+              sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol),
+              0),
+            sqlite3PExpr(pParse, TK_DOT, 
+              sqlite3PExpr(pParse, TK_ID, 0, 0, &tNew),
+              sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol),
+              0),
+            0);
+        pWhen = sqlite3ExprAnd(db, pWhen, pEq);
+      }
+  
+      if( action!=OE_Restrict && (action!=OE_Cascade || pChanges) ){
+        Expr *pNew;
+        if( action==OE_Cascade ){
+          pNew = sqlite3PExpr(pParse, TK_DOT, 
+            sqlite3PExpr(pParse, TK_ID, 0, 0, &tNew),
+            sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol)
+          , 0);
+        }else if( action==OE_SetDflt ){
+          Expr *pDflt = pFKey->pFrom->aCol[iFromCol].pDflt;
+          if( pDflt ){
+            pNew = sqlite3ExprDup(db, pDflt, 0);
+          }else{
+            pNew = sqlite3PExpr(pParse, TK_NULL, 0, 0, 0);
+          }
+        }else{
+          pNew = sqlite3PExpr(pParse, TK_NULL, 0, 0, 0);
+        }
+        pList = sqlite3ExprListAppend(pParse, pList, pNew);
+        sqlite3ExprListSetName(pParse, pList, &tFromCol, 0);
+      }
+    }
+    sqlite3DbFree(db, aiCol);
+
+    zFrom = pFKey->pFrom->zName;
+    nFrom = sqlite3Strlen30(zFrom);
+
+    if( action==OE_Restrict ){
+      Token tFrom;
+      Expr *pRaise; 
+
+      tFrom.z = zFrom;
+      tFrom.n = nFrom;
+      pRaise = sqlite3Expr(db, TK_RAISE, "foreign key constraint failed");
+      if( pRaise ){
+        pRaise->affinity = OE_Abort;
+      }
+      pSelect = sqlite3SelectNew(pParse, 
+          sqlite3ExprListAppend(pParse, 0, pRaise),
+          sqlite3SrcListAppend(db, 0, &tFrom, 0),
+          pWhere,
+          0, 0, 0, 0, 0, 0
+      );
+      pWhere = 0;
+    }
+
+    /* Disable lookaside memory allocation */
+    enableLookaside = db->lookaside.bEnabled;
+    db->lookaside.bEnabled = 0;
+
+    pTrigger = (Trigger *)sqlite3DbMallocZero(db, 
+        sizeof(Trigger) +         /* struct Trigger */
+        sizeof(TriggerStep) +     /* Single step in trigger program */
+        nFrom + 1                 /* Space for pStep->target.z */
+    );
+    if( pTrigger ){
+      pStep = pTrigger->step_list = (TriggerStep *)&pTrigger[1];
+      pStep->target.z = (char *)&pStep[1];
+      pStep->target.n = nFrom;
+      memcpy((char *)pStep->target.z, zFrom, nFrom);
+  
+      pStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+      pStep->pExprList = sqlite3ExprListDup(db, pList, EXPRDUP_REDUCE);
+      pStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
+      if( pWhen ){
+        pWhen = sqlite3PExpr(pParse, TK_NOT, pWhen, 0, 0);
+        pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
+      }
+    }
+
+    /* Re-enable the lookaside buffer, if it was disabled earlier. */
+    db->lookaside.bEnabled = enableLookaside;
+
+    sqlite3ExprDelete(db, pWhere);
+    sqlite3ExprDelete(db, pWhen);
+    sqlite3ExprListDelete(db, pList);
+    sqlite3SelectDelete(db, pSelect);
+    if( db->mallocFailed==1 ){
+      fkTriggerDelete(db, pTrigger);
+      return 0;
+    }
+    assert( pStep!=0 );
+
+    switch( action ){
+      case OE_Restrict:
+        pStep->op = TK_SELECT; 
+        break;
+      case OE_Cascade: 
+        if( !pChanges ){ 
+          pStep->op = TK_DELETE; 
+          break; 
+        }
+      default:
+        pStep->op = TK_UPDATE;
+    }
+    pStep->pTrig = pTrigger;
+    pTrigger->pSchema = pTab->pSchema;
+    pTrigger->pTabSchema = pTab->pSchema;
+    pFKey->apTrigger[iAction] = pTrigger;
+    pTrigger->op = (pChanges ? TK_UPDATE : TK_DELETE);
+  }
+
+  return pTrigger;
+}
+
+/*
+** This function is called when deleting or updating a row to implement
+** any required CASCADE, SET NULL or SET DEFAULT actions.
+*/
+SQLITE_PRIVATE void sqlite3FkActions(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated or deleted from */
+  ExprList *pChanges,             /* Change-list for UPDATE, NULL for DELETE */
+  int regOld                      /* Address of array containing old row */
+){
+  /* If foreign-key support is enabled, iterate through all FKs that 
+  ** refer to table pTab. If there is an action associated with the FK 
+  ** for this operation (either update or delete), invoke the associated 
+  ** trigger sub-program.  */
+  if( pParse->db->flags&SQLITE_ForeignKeys ){
+    FKey *pFKey;                  /* Iterator variable */
+    for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
+      Trigger *pAction = fkActionTrigger(pParse, pTab, pFKey, pChanges);
+      if( pAction ){
+        sqlite3CodeRowTriggerDirect(pParse, pAction, pTab, regOld, OE_Abort, 0);
+      }
+    }
+  }
+}
+
+#endif /* ifndef SQLITE_OMIT_TRIGGER */
+
+/*
+** Free all memory associated with foreign key definitions attached to
+** table pTab. Remove the deleted foreign keys from the Schema.fkeyHash
+** hash table.
+*/
+SQLITE_PRIVATE void sqlite3FkDelete(sqlite3 *db, Table *pTab){
+  FKey *pFKey;                    /* Iterator variable */
+  FKey *pNext;                    /* Copy of pFKey->pNextFrom */
+
+  assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pTab->pSchema) );
+  for(pFKey=pTab->pFKey; pFKey; pFKey=pNext){
+
+    /* Remove the FK from the fkeyHash hash table. */
+    if( !db || db->pnBytesFreed==0 ){
+      if( pFKey->pPrevTo ){
+        pFKey->pPrevTo->pNextTo = pFKey->pNextTo;
+      }else{
+        void *p = (void *)pFKey->pNextTo;
+        const char *z = (p ? pFKey->pNextTo->zTo : pFKey->zTo);
+        sqlite3HashInsert(&pTab->pSchema->fkeyHash, z, sqlite3Strlen30(z), p);
+      }
+      if( pFKey->pNextTo ){
+        pFKey->pNextTo->pPrevTo = pFKey->pPrevTo;
+      }
+    }
+
+    /* EV: R-30323-21917 Each foreign key constraint in SQLite is
+    ** classified as either immediate or deferred.
+    */
+    assert( pFKey->isDeferred==0 || pFKey->isDeferred==1 );
+
+    /* Delete any triggers created to implement actions for this FK. */
+#ifndef SQLITE_OMIT_TRIGGER
+    fkTriggerDelete(db, pFKey->apTrigger[0]);
+    fkTriggerDelete(db, pFKey->apTrigger[1]);
+#endif
+
+    pNext = pFKey->pNextFrom;
+    sqlite3DbFree(db, pFKey);
+  }
+}
+#endif /* ifndef SQLITE_OMIT_FOREIGN_KEY */
+
+/************** End of fkey.c ************************************************/
 /************** Begin file insert.c ******************************************/
 /*
 ** 2001 September 15
@@ -67274,14 +87969,32 @@ SQLITE_PRIVATE void sqlite3RegisterGlobalFunctions(void){
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** to handle INSERT statements in SQLite.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
-** Set P4 of the most recently inserted opcode to a column affinity
-** string for index pIdx. A column affinity string has one character
-** for each column in the table, according to the affinity of the column:
+** Generate code that will open a table for reading.
+*/
+SQLITE_PRIVATE void sqlite3OpenTable(
+  Parse *p,       /* Generate code into this VDBE */
+  int iCur,       /* The cursor number of the table */
+  int iDb,        /* The database index in sqlite3.aDb[] */
+  Table *pTab,    /* The table to be opened */
+  int opcode      /* OP_OpenRead or OP_OpenWrite */
+){
+  Vdbe *v;
+  if( IsVirtual(pTab) ) return;
+  v = sqlite3GetVdbe(p);
+  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
+  sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite)?1:0, pTab->zName);
+  sqlite3VdbeAddOp3(v, opcode, iCur, pTab->tnum, iDb);
+  sqlite3VdbeChangeP4(v, -1, SQLITE_INT_TO_PTR(pTab->nCol), P4_INT32);
+  VdbeComment((v, "%s", pTab->zName));
+}
+
+/*
+** Return a pointer to the column affinity string associated with index
+** pIdx. A column affinity string has one character for each column in 
+** the table, according to the affinity of the column:
 **
 **  Character      Column affinity
 **  ------------------------------
@@ -67291,10 +88004,14 @@ SQLITE_PRIVATE void sqlite3RegisterGlobalFunctions(void){
 **  'd'            INTEGER
 **  'e'            REAL
 **
-** An extra 'b' is appended to the end of the string to cover the
+** An extra 'd' is appended to the end of the string to cover the
 ** rowid that appears as the last column in every index.
+**
+** Memory for the buffer containing the column index affinity string
+** is managed along with the rest of the Index structure. It will be
+** released when sqlite3DeleteIndex() is called.
 */
-SQLITE_PRIVATE void sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
+SQLITE_PRIVATE const char *sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
   if( !pIdx->zColAff ){
     /* The first time a column affinity string for a particular index is
     ** required, it is allocated and populated here. It is then stored as
@@ -67307,19 +88024,19 @@ SQLITE_PRIVATE void sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
     int n;
     Table *pTab = pIdx->pTable;
     sqlite3 *db = sqlite3VdbeDb(v);
-    pIdx->zColAff = (char *)sqlite3Malloc(pIdx->nColumn+2);
+    pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+2);
     if( !pIdx->zColAff ){
       db->mallocFailed = 1;
-      return;
+      return 0;
     }
     for(n=0; n<pIdx->nColumn; n++){
       pIdx->zColAff[n] = pTab->aCol[pIdx->aiColumn[n]].affinity;
     }
-    pIdx->zColAff[n++] = SQLITE_AFF_NONE;
+    pIdx->zColAff[n++] = SQLITE_AFF_INTEGER;
     pIdx->zColAff[n] = 0;
   }
  
-  sqlite3VdbeChangeP4(v, -1, pIdx->zColAff, 0);
+  return pIdx->zColAff;
 }
 
 /*
@@ -67349,7 +88066,7 @@ SQLITE_PRIVATE void sqlite3TableAffinityStr(Vdbe *v, Table *pTab){
     int i;
     sqlite3 *db = sqlite3VdbeDb(v);
 
-    zColAff = (char *)sqlite3Malloc(pTab->nCol+1);
+    zColAff = (char *)sqlite3DbMallocRaw(0, pTab->nCol+1);
     if( !zColAff ){
       db->mallocFailed = 1;
       return;
@@ -67363,7 +88080,7 @@ SQLITE_PRIVATE void sqlite3TableAffinityStr(Vdbe *v, Table *pTab){
     pTab->zColAff = zColAff;
   }
 
-  sqlite3VdbeChangeP4(v, -1, pTab->zColAff, 0);
+  sqlite3VdbeChangeP4(v, -1, pTab->zColAff, P4_TRANSIENT);
 }
 
 /*
@@ -67373,9 +88090,14 @@ SQLITE_PRIVATE void sqlite3TableAffinityStr(Vdbe *v, Table *pTab){
 ** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can 
 ** run without using temporary table for the results of the SELECT. 
 */
-static int readsTable(Vdbe *v, int iStartAddr, int iDb, Table *pTab){
+static int readsTable(Parse *p, int iStartAddr, int iDb, Table *pTab){
+  Vdbe *v = sqlite3GetVdbe(p);
   int i;
   int iEnd = sqlite3VdbeCurrentAddr(v);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
+#endif
+
   for(i=iStartAddr; i<iEnd; i++){
     VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
     assert( pOp!=0 );
@@ -67392,7 +88114,7 @@ static int readsTable(Vdbe *v, int iStartAddr, int iDb, Table *pTab){
       }
     }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-    if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pTab->pVtab ){
+    if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
       assert( pOp->p4.pVtab!=0 );
       assert( pOp->p4type==P4_VTAB );
       return 1;
@@ -67404,22 +88126,24 @@ static int readsTable(Vdbe *v, int iStartAddr, int iDb, Table *pTab){
 
 #ifndef SQLITE_OMIT_AUTOINCREMENT
 /*
-** Write out code to initialize the autoincrement logic.  This code
-** looks up the current autoincrement value in the sqlite_sequence
-** table and stores that value in a register.  Code generated by
-** autoIncStep() will keep that register holding the largest
-** rowid value.  Code generated by autoIncEnd() will write the new
-** largest value of the counter back into the sqlite_sequence table.
+** Locate or create an AutoincInfo structure associated with table pTab
+** which is in database iDb.  Return the register number for the register
+** that holds the maximum rowid.
 **
-** This routine returns the index of the mem[] cell that contains
-** the maximum rowid counter.
+** There is at most one AutoincInfo structure per table even if the
+** same table is autoincremented multiple times due to inserts within
+** triggers.  A new AutoincInfo structure is created if this is the
+** first use of table pTab.  On 2nd and subsequent uses, the original
+** AutoincInfo structure is used.
 **
-** Three consecutive registers are allocated by this routine.  The
-** first two hold the name of the target table and the maximum rowid 
-** inserted into the target table, respectively.
-** The third holds the rowid in sqlite_sequence where we will
-** write back the revised maximum rowid.  This routine returns the
-** index of the second of these three registers.
+** Three memory locations are allocated:
+**
+**   (1)  Register to hold the name of the pTab table.
+**   (2)  Register to hold the maximum ROWID of pTab.
+**   (3)  Register to hold the rowid in sqlite_sequence of pTab
+**
+** The 2nd register is the one that is returned.  That is all the
+** insert routine needs to know about.
 */
 static int autoIncBegin(
   Parse *pParse,      /* Parsing context */
@@ -67428,31 +88152,66 @@ static int autoIncBegin(
 ){
   int memId = 0;      /* Register holding maximum rowid */
   if( pTab->tabFlags & TF_Autoincrement ){
-    Vdbe *v = pParse->pVdbe;
-    Db *pDb = &pParse->db->aDb[iDb];
-    int iCur = pParse->nTab;
-    int addr;               /* Address of the top of the loop */
-    assert( v );
-    pParse->nMem++;         /* Holds name of table */
-    memId = ++pParse->nMem;
-    pParse->nMem++;
-    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
-    addr = sqlite3VdbeCurrentAddr(v);
-    sqlite3VdbeAddOp4(v, OP_String8, 0, memId-1, 0, pTab->zName, 0);
-    sqlite3VdbeAddOp2(v, OP_Rewind, iCur, addr+9);
-    sqlite3VdbeAddOp3(v, OP_Column, iCur, 0, memId);
-    sqlite3VdbeAddOp3(v, OP_Ne, memId-1, addr+7, memId);
-    sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
-    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, memId+1);
-    sqlite3VdbeAddOp3(v, OP_Column, iCur, 1, memId);
-    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr+9);
-    sqlite3VdbeAddOp2(v, OP_Next, iCur, addr+2);
-    sqlite3VdbeAddOp2(v, OP_Integer, 0, memId);
-    sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
+    Parse *pToplevel = sqlite3ParseToplevel(pParse);
+    AutoincInfo *pInfo;
+
+    pInfo = pToplevel->pAinc;
+    while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
+    if( pInfo==0 ){
+      pInfo = sqlite3DbMallocRaw(pParse->db, sizeof(*pInfo));
+      if( pInfo==0 ) return 0;
+      pInfo->pNext = pToplevel->pAinc;
+      pToplevel->pAinc = pInfo;
+      pInfo->pTab = pTab;
+      pInfo->iDb = iDb;
+      pToplevel->nMem++;                  /* Register to hold name of table */
+      pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
+      pToplevel->nMem++;                  /* Rowid in sqlite_sequence */
+    }
+    memId = pInfo->regCtr;
   }
   return memId;
 }
 
+/*
+** This routine generates code that will initialize all of the
+** register used by the autoincrement tracker.  
+*/
+SQLITE_PRIVATE void sqlite3AutoincrementBegin(Parse *pParse){
+  AutoincInfo *p;            /* Information about an AUTOINCREMENT */
+  sqlite3 *db = pParse->db;  /* The database connection */
+  Db *pDb;                   /* Database only autoinc table */
+  int memId;                 /* Register holding max rowid */
+  int addr;                  /* A VDBE address */
+  Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
+
+  /* This routine is never called during trigger-generation.  It is
+  ** only called from the top-level */
+  assert( pParse->pTriggerTab==0 );
+  assert( pParse==sqlite3ParseToplevel(pParse) );
+
+  assert( v );   /* We failed long ago if this is not so */
+  for(p = pParse->pAinc; p; p = p->pNext){
+    pDb = &db->aDb[p->iDb];
+    memId = p->regCtr;
+    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
+    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
+    sqlite3VdbeAddOp3(v, OP_Null, 0, memId, memId+1);
+    addr = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, memId-1, 0, p->pTab->zName, 0);
+    sqlite3VdbeAddOp2(v, OP_Rewind, 0, addr+9);
+    sqlite3VdbeAddOp3(v, OP_Column, 0, 0, memId);
+    sqlite3VdbeAddOp3(v, OP_Ne, memId-1, addr+7, memId);
+    sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
+    sqlite3VdbeAddOp2(v, OP_Rowid, 0, memId+1);
+    sqlite3VdbeAddOp3(v, OP_Column, 0, 1, memId);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr+9);
+    sqlite3VdbeAddOp2(v, OP_Next, 0, addr+2);
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, memId);
+    sqlite3VdbeAddOp0(v, OP_Close);
+  }
+}
+
 /*
 ** Update the maximum rowid for an autoincrement calculation.
 **
@@ -67468,32 +88227,44 @@ static void autoIncStep(Parse *pParse, int memId, int regRowid){
 }
 
 /*
-** After doing one or more inserts, the maximum rowid is stored
-** in reg[memId].  Generate code to write this value back into the
-** the sqlite_sequence table.
+** This routine generates the code needed to write autoincrement
+** maximum rowid values back into the sqlite_sequence register.
+** Every statement that might do an INSERT into an autoincrement
+** table (either directly or through triggers) needs to call this
+** routine just before the "exit" code.
 */
-static void autoIncEnd(
-  Parse *pParse,     /* The parsing context */
-  int iDb,           /* Index of the database holding pTab */
-  Table *pTab,       /* Table we are inserting into */
-  int memId          /* Memory cell holding the maximum rowid */
-){
-  if( pTab->tabFlags & TF_Autoincrement ){
-    int iCur = pParse->nTab;
-    Vdbe *v = pParse->pVdbe;
-    Db *pDb = &pParse->db->aDb[iDb];
-    int j1;
-    int iRec = ++pParse->nMem;    /* Memory cell used for record */
+SQLITE_PRIVATE void sqlite3AutoincrementEnd(Parse *pParse){
+  AutoincInfo *p;
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
 
-    assert( v );
-    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
+  assert( v );
+  for(p = pParse->pAinc; p; p = p->pNext){
+    Db *pDb = &db->aDb[p->iDb];
+    int j1, j2, j3, j4, j5;
+    int iRec;
+    int memId = p->regCtr;
+
+    iRec = sqlite3GetTempReg(pParse);
+    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
+    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
     j1 = sqlite3VdbeAddOp1(v, OP_NotNull, memId+1);
-    sqlite3VdbeAddOp2(v, OP_NewRowid, iCur, memId+1);
+    j2 = sqlite3VdbeAddOp0(v, OP_Rewind);
+    j3 = sqlite3VdbeAddOp3(v, OP_Column, 0, 0, iRec);
+    j4 = sqlite3VdbeAddOp3(v, OP_Eq, memId-1, 0, iRec);
+    sqlite3VdbeAddOp2(v, OP_Next, 0, j3);
+    sqlite3VdbeJumpHere(v, j2);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, 0, memId+1);
+    j5 = sqlite3VdbeAddOp0(v, OP_Goto);
+    sqlite3VdbeJumpHere(v, j4);
+    sqlite3VdbeAddOp2(v, OP_Rowid, 0, memId+1);
     sqlite3VdbeJumpHere(v, j1);
+    sqlite3VdbeJumpHere(v, j5);
     sqlite3VdbeAddOp3(v, OP_MakeRecord, memId-1, 2, iRec);
-    sqlite3VdbeAddOp3(v, OP_Insert, iCur, iRec, memId+1);
+    sqlite3VdbeAddOp3(v, OP_Insert, 0, iRec, memId+1);
     sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
-    sqlite3VdbeAddOp1(v, OP_Close, iCur);
+    sqlite3VdbeAddOp0(v, OP_Close);
+    sqlite3ReleaseTempReg(pParse, iRec);
   }
 }
 #else
@@ -67503,7 +88274,6 @@ static void autoIncEnd(
 */
 # define autoIncBegin(A,B,C) (0)
 # define autoIncStep(A,B,C)
-# define autoIncEnd(A,B,C,D)
 #endif /* SQLITE_OMIT_AUTOINCREMENT */
 
 
@@ -67644,7 +88414,6 @@ SQLITE_PRIVATE void sqlite3Insert(
   int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
   int addrSelect = 0;   /* Address of coroutine that implements the SELECT */
   SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
-  int newIdx = -1;      /* Cursor for the NEW pseudo-table */
   int iDb;              /* Index of database holding TABLE */
   Db *pDb;              /* The database containing table being inserted into */
   int appendFlag = 0;   /* True if the insert is likely to be an append */
@@ -67656,14 +88425,13 @@ SQLITE_PRIVATE void sqlite3Insert(
   int regIns;           /* Block of regs holding rowid+data being inserted */
   int regRowid;         /* registers holding insert rowid */
   int regData;          /* register holding first column to insert */
-  int regRecord;        /* Holds the assemblied row record */
   int regEof = 0;       /* Register recording end of SELECT data */
   int *aRegIdx = 0;     /* One register allocated to each index */
 
-
 #ifndef SQLITE_OMIT_TRIGGER
   int isView;                 /* True if attempting to insert into a view */
-  int triggers_exist = 0;     /* True if there are FOR EACH ROW triggers */
+  Trigger *pTrigger;          /* List of triggers on pTab, if required */
+  int tmask;                  /* Mask of trigger times */
 #endif
 
   db = pParse->db;
@@ -67676,7 +88444,7 @@ SQLITE_PRIVATE void sqlite3Insert(
   */
   assert( pTabList->nSrc==1 );
   zTab = pTabList->a[0].zName;
-  if( zTab==0 ) goto insert_cleanup;
+  if( NEVER(zTab==0) ) goto insert_cleanup;
   pTab = sqlite3SrcListLookup(pParse, pTabList);
   if( pTab==0 ){
     goto insert_cleanup;
@@ -67693,25 +88461,18 @@ SQLITE_PRIVATE void sqlite3Insert(
   ** inserted into is a view
   */
 #ifndef SQLITE_OMIT_TRIGGER
-  triggers_exist = sqlite3TriggersExist(pTab, TK_INSERT, 0);
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
   isView = pTab->pSelect!=0;
 #else
-# define triggers_exist 0
+# define pTrigger 0
+# define tmask 0
 # define isView 0
 #endif
 #ifdef SQLITE_OMIT_VIEW
 # undef isView
 # define isView 0
 #endif
-
-  /* Ensure that:
-  *  (a) the table is not read-only, 
-  *  (b) that if it is a view then ON INSERT triggers exist
-  */
-  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
-    goto insert_cleanup;
-  }
-  assert( pTab!=0 );
+  assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
 
   /* If pTab is really a view, make sure it has been initialized.
   ** ViewGetColumnNames() is a no-op if pTab is not a view (or virtual 
@@ -67721,17 +88482,20 @@ SQLITE_PRIVATE void sqlite3Insert(
     goto insert_cleanup;
   }
 
+  /* Ensure that:
+  *  (a) the table is not read-only, 
+  *  (b) that if it is a view then ON INSERT triggers exist
+  */
+  if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
+    goto insert_cleanup;
+  }
+
   /* Allocate a VDBE
   */
   v = sqlite3GetVdbe(pParse);
   if( v==0 ) goto insert_cleanup;
   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
-  sqlite3BeginWriteOperation(pParse, pSelect || triggers_exist, iDb);
-
-  /* if there are row triggers, allocate a temp table for new.* references. */
-  if( triggers_exist ){
-    newIdx = pParse->nTab++;
-  }
+  sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
 
 #ifndef SQLITE_OMIT_XFER_OPT
   /* If the statement is of the form
@@ -67744,9 +88508,9 @@ SQLITE_PRIVATE void sqlite3Insert(
   ** This is the 2nd template.
   */
   if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
-    assert( !triggers_exist );
+    assert( !pTrigger );
     assert( pList==0 );
-    goto insert_cleanup;
+    goto insert_end;
   }
 #endif /* SQLITE_OMIT_XFER_OPT */
 
@@ -67790,25 +88554,26 @@ SQLITE_PRIVATE void sqlite3Insert(
     VdbeComment((v, "SELECT eof flag"));
     sqlite3SelectDestInit(&dest, SRT_Coroutine, ++pParse->nMem);
     addrSelect = sqlite3VdbeCurrentAddr(v)+2;
-    sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iParm);
+    sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iSDParm);
     j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
     VdbeComment((v, "Jump over SELECT coroutine"));
 
     /* Resolve the expressions in the SELECT statement and execute it. */
     rc = sqlite3Select(pParse, pSelect, &dest);
-    if( rc || pParse->nErr || db->mallocFailed ){
+    assert( pParse->nErr==0 || rc );
+    if( rc || NEVER(pParse->nErr) || db->mallocFailed ){
       goto insert_cleanup;
     }
     sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);         /* EOF <- 1 */
-    sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);   /* yield X */
+    sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);   /* yield X */
     sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
     VdbeComment((v, "End of SELECT coroutine"));
     sqlite3VdbeJumpHere(v, j1);                          /* label B: */
 
-    regFromSelect = dest.iMem;
+    regFromSelect = dest.iSdst;
     assert( pSelect->pEList );
     nColumn = pSelect->pEList->nExpr;
-    assert( dest.nMem==nColumn );
+    assert( dest.nSdst==nColumn );
 
     /* Set useTempTable to TRUE if the result of the SELECT statement
     ** should be written into a temporary table (template 4).  Set to
@@ -67819,7 +88584,7 @@ SQLITE_PRIVATE void sqlite3Insert(
     ** of the tables being read by the SELECT statement.  Also use a 
     ** temp table in the case of row triggers.
     */
-    if( triggers_exist || readsTable(v, addrSelect, iDb, pTab) ){
+    if( pTrigger || readsTable(pParse, addrSelect, iDb, pTab) ){
       useTempTable = 1;
     }
 
@@ -67844,7 +88609,7 @@ SQLITE_PRIVATE void sqlite3Insert(
       regRec = sqlite3GetTempReg(pParse);
       regTempRowid = sqlite3GetTempReg(pParse);
       sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
-      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
+      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
       addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
       sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
       sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
@@ -67882,7 +88647,7 @@ SQLITE_PRIVATE void sqlite3Insert(
   if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
     sqlite3ErrorMsg(pParse, 
        "table %S has %d columns but %d values were supplied",
-       pTabList, 0, pTab->nCol, nColumn);
+       pTabList, 0, pTab->nCol-nHidden, nColumn);
     goto insert_cleanup;
   }
   if( pColumn!=0 && nColumn!=pColumn->nId ){
@@ -67921,7 +88686,7 @@ SQLITE_PRIVATE void sqlite3Insert(
         }else{
           sqlite3ErrorMsg(pParse, "table %S has no column named %s",
               pTabList, 0, pColumn->a[i].zName);
-          pParse->nErr++;
+          pParse->checkSchema = 1;
           goto insert_cleanup;
         }
       }
@@ -67935,13 +88700,6 @@ SQLITE_PRIVATE void sqlite3Insert(
   if( pColumn==0 && nColumn>0 ){
     keyColumn = pTab->iPKey;
   }
-
-  /* Open the temp table for FOR EACH ROW triggers
-  */
-  if( triggers_exist ){
-    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
-    sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0);
-  }
     
   /* Initialize the count of rows to be inserted
   */
@@ -67988,14 +88746,13 @@ SQLITE_PRIVATE void sqlite3Insert(
     **         goto C
     **      D: ...
     */
-    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
+    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
     addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
   }
 
   /* Allocate registers for holding the rowid of the new row,
   ** the content of the new row, and the assemblied row record.
   */
-  regRecord = ++pParse->nMem;
   regRowid = regIns = pParse->nMem+1;
   pParse->nMem += pTab->nCol + 1;
   if( IsVirtual(pTab) ){
@@ -68007,10 +88764,8 @@ SQLITE_PRIVATE void sqlite3Insert(
   /* Run the BEFORE and INSTEAD OF triggers, if there are any
   */
   endOfLoop = sqlite3VdbeMakeLabel(v);
-  if( triggers_exist & TRIGGER_BEFORE ){
-    int regTrigRowid;
-    int regCols;
-    int regRec;
+  if( tmask & TRIGGER_BEFORE ){
+    int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
 
     /* build the NEW.* reference row.  Note that if there is an INTEGER
     ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
@@ -68018,29 +88773,29 @@ SQLITE_PRIVATE void sqlite3Insert(
     ** we do not know what the unique ID will be (because the insert has
     ** not happened yet) so we substitute a rowid of -1
     */
-    regTrigRowid = sqlite3GetTempReg(pParse);
     if( keyColumn<0 ){
-      sqlite3VdbeAddOp2(v, OP_Integer, -1, regTrigRowid);
-    }else if( useTempTable ){
-      sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regTrigRowid);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
     }else{
       int j1;
-      assert( pSelect==0 );  /* Otherwise useTempTable is true */
-      sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regTrigRowid);
-      j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regTrigRowid);
-      sqlite3VdbeAddOp2(v, OP_Integer, -1, regTrigRowid);
+      if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regCols);
+      }else{
+        assert( pSelect==0 );  /* Otherwise useTempTable is true */
+        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regCols);
+      }
+      j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
       sqlite3VdbeJumpHere(v, j1);
-      sqlite3VdbeAddOp1(v, OP_MustBeInt, regTrigRowid);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols);
     }
 
     /* Cannot have triggers on a virtual table. If it were possible,
     ** this block would have to account for hidden column.
     */
-    assert(!IsVirtual(pTab));
+    assert( !IsVirtual(pTab) );
 
     /* Create the new column data
     */
-    regCols = sqlite3GetTempRange(pParse, pTab->nCol);
     for(i=0; i<pTab->nCol; i++){
       if( pColumn==0 ){
         j = i;
@@ -68049,17 +88804,15 @@ SQLITE_PRIVATE void sqlite3Insert(
           if( pColumn->a[j].idx==i ) break;
         }
       }
-      if( pColumn && j>=pColumn->nId ){
-        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i);
+      if( (!useTempTable && !pList) || (pColumn && j>=pColumn->nId) ){
+        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i+1);
       }else if( useTempTable ){
-        sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i); 
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i+1); 
       }else{
         assert( pSelect==0 ); /* Otherwise useTempTable is true */
-        sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i);
+        sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i+1);
       }
     }
-    regRec = sqlite3GetTempReg(pParse);
-    sqlite3VdbeAddOp3(v, OP_MakeRecord, regCols, pTab->nCol, regRec);
 
     /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
     ** do not attempt any conversions before assembling the record.
@@ -68067,18 +88820,15 @@ SQLITE_PRIVATE void sqlite3Insert(
     ** table column affinities.
     */
     if( !isView ){
+      sqlite3VdbeAddOp2(v, OP_Affinity, regCols+1, pTab->nCol);
       sqlite3TableAffinityStr(v, pTab);
     }
-    sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRec, regTrigRowid);
-    sqlite3ReleaseTempReg(pParse, regRec);
-    sqlite3ReleaseTempReg(pParse, regTrigRowid);
-    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol);
 
     /* Fire BEFORE or INSTEAD OF triggers */
-    if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TRIGGER_BEFORE, pTab, 
-        newIdx, -1, onError, endOfLoop, 0, 0) ){
-      goto insert_cleanup;
-    }
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE, 
+        pTab, regCols-pTab->nCol-1, onError, endOfLoop);
+
+    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
   }
 
   /* Push the record number for the new entry onto the stack.  The
@@ -68099,8 +88849,8 @@ SQLITE_PRIVATE void sqlite3Insert(
       }else{
         VdbeOp *pOp;
         sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regRowid);
-        pOp = sqlite3VdbeGetOp(v, sqlite3VdbeCurrentAddr(v) - 1);
-        if( pOp && pOp->opcode==OP_Null && !IsVirtual(pTab) ){
+        pOp = sqlite3VdbeGetOp(v, -1);
+        if( ALWAYS(pOp) && pOp->opcode==OP_Null && !IsVirtual(pTab) ){
           appendFlag = 1;
           pOp->opcode = OP_NewRowid;
           pOp->p1 = baseCur;
@@ -68174,33 +88924,22 @@ SQLITE_PRIVATE void sqlite3Insert(
     */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
     if( IsVirtual(pTab) ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
       sqlite3VtabMakeWritable(pParse, pTab);
-      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns,
-                     (const char*)pTab->pVtab, P4_VTAB);
+      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
+      sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
+      sqlite3MayAbort(pParse);
     }else
 #endif
     {
-      sqlite3GenerateConstraintChecks(
-          pParse,
-          pTab,
-          baseCur,
-          regIns,
-          aRegIdx,
-          keyColumn>=0,
-          0,
-          onError,
-          endOfLoop
+      int isReplace;    /* Set to true if constraints may cause a replace */
+      sqlite3GenerateConstraintChecks(pParse, pTab, baseCur, regIns, aRegIdx,
+          keyColumn>=0, 0, onError, endOfLoop, &isReplace
       );
+      sqlite3FkCheck(pParse, pTab, 0, regIns);
       sqlite3CompleteInsertion(
-          pParse,
-          pTab,
-          baseCur,
-          regIns,
-          aRegIdx,
-          0,
-          (triggers_exist & TRIGGER_AFTER)!=0 ? newIdx : -1,
-          appendFlag
-       );
+          pParse, pTab, baseCur, regIns, aRegIdx, 0, appendFlag, isReplace==0
+      );
     }
   }
 
@@ -68210,12 +88949,10 @@ SQLITE_PRIVATE void sqlite3Insert(
     sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
   }
 
-  if( triggers_exist ){
+  if( pTrigger ){
     /* Code AFTER triggers */
-    if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TRIGGER_AFTER, pTab,
-          newIdx, -1, onError, endOfLoop, 0, 0) ){
-      goto insert_cleanup;
-    }
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER, 
+        pTab, regData-2-pTab->nCol, onError, endOfLoop);
   }
 
   /* The bottom of the main insertion loop, if the data source
@@ -68239,18 +88976,21 @@ SQLITE_PRIVATE void sqlite3Insert(
     }
   }
 
+insert_end:
   /* Update the sqlite_sequence table by storing the content of the
-  ** counter value in memory regAutoinc back into the sqlite_sequence
-  ** table.
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
   */
-  autoIncEnd(pParse, iDb, pTab, regAutoinc);
+  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
 
   /*
   ** Return the number of rows inserted. If this routine is 
   ** generating code because of a call to sqlite3NestedParse(), do not
   ** invoke the callback function.
   */
-  if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){
+  if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
     sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
     sqlite3VdbeSetNumCols(v, 1);
     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
@@ -68264,31 +89004,43 @@ insert_cleanup:
   sqlite3DbFree(db, aRegIdx);
 }
 
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** thely may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+#ifdef tmask
+ #undef tmask
+#endif
+
+
 /*
 ** Generate code to do constraint checks prior to an INSERT or an UPDATE.
 **
 ** The input is a range of consecutive registers as follows:
 **
-**    1.  The rowid of the row to be updated before the update.  This
-**        value is omitted unless we are doing an UPDATE that involves a
-**        change to the record number or writing to a virtual table.
+**    1.  The rowid of the row after the update.
 **
-**    2.  The rowid of the row after the update.
-**
-**    3.  The data in the first column of the entry after the update.
+**    2.  The data in the first column of the entry after the update.
 **
 **    i.  Data from middle columns...
 **
 **    N.  The data in the last column of the entry after the update.
 **
-** The regRowid parameter is the index of the register containing (2).
+** The regRowid parameter is the index of the register containing (1).
 **
-** The old rowid shown as entry (1) above is omitted unless both isUpdate
-** and rowidChng are 1.  isUpdate is true for UPDATEs and false for
-** INSERTs.  RowidChng means that the new rowid is explicitly specified by
-** the update or insert statement.  If rowidChng is false, it means that
-** the rowid is computed automatically in an insert or that the rowid value
-** is not modified by the update.
+** If isUpdate is true and rowidChng is non-zero, then rowidChng contains
+** the address of a register containing the rowid before the update takes
+** place. isUpdate is true for UPDATEs and false for INSERTs. If isUpdate
+** is false, indicating an INSERT statement, then a non-zero rowidChng 
+** indicates that the rowid was explicitly specified as part of the
+** INSERT statement. If rowidChng is false, it means that  the rowid is
+** computed automatically in an insert or that the rowid value is not 
+** modified by an update.
 **
 ** The code generated by this routine store new index entries into
 ** registers identified by aRegIdx[].  No index entry is created for
@@ -68312,7 +89064,7 @@ insert_cleanup:
 **                                cause sqlite3_exec() to return immediately
 **                                with SQLITE_CONSTRAINT.
 **
-**  any              FAIL         Sqlite_exec() returns immediately with a
+**  any              FAIL         Sqlite3_exec() returns immediately with a
 **                                return code of SQLITE_CONSTRAINT.  The
 **                                transaction is not rolled back and any
 **                                prior changes are retained.
@@ -68350,27 +89102,29 @@ SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
   int rowidChng,      /* True if the rowid might collide with existing entry */
   int isUpdate,       /* True for UPDATE, False for INSERT */
   int overrideError,  /* Override onError to this if not OE_Default */
-  int ignoreDest      /* Jump to this label on an OE_Ignore resolution */
+  int ignoreDest,     /* Jump to this label on an OE_Ignore resolution */
+  int *pbMayReplace   /* OUT: Set to true if constraint may cause a replace */
 ){
-  int i;
-  Vdbe *v;
-  int nCol;
-  int onError;
+  int i;              /* loop counter */
+  Vdbe *v;            /* VDBE under constrution */
+  int nCol;           /* Number of columns */
+  int onError;        /* Conflict resolution strategy */
   int j1;             /* Addresss of jump instruction */
   int j2 = 0, j3;     /* Addresses of jump instructions */
   int regData;        /* Register containing first data column */
-  int iCur;
-  Index *pIdx;
-  int seenReplace = 0;
-  int hasTwoRowids = (isUpdate && rowidChng);
+  int iCur;           /* Table cursor number */
+  Index *pIdx;         /* Pointer to one of the indices */
+  sqlite3 *db;         /* Database connection */
+  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
+  int regOldRowid = (rowidChng && isUpdate) ? rowidChng : regRowid;
 
+  db = pParse->db;
   v = sqlite3GetVdbe(pParse);
   assert( v!=0 );
   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
   nCol = pTab->nCol;
   regData = regRowid + 1;
 
-
   /* Test all NOT NULL constraints.
   */
   for(i=0; i<nCol; i++){
@@ -68387,46 +89141,59 @@ SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
     if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
       onError = OE_Abort;
     }
-    j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regData+i);
     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
         || onError==OE_Ignore || onError==OE_Replace );
     switch( onError ){
-      case OE_Rollback:
       case OE_Abort:
+        sqlite3MayAbort(pParse);
+      case OE_Rollback:
       case OE_Fail: {
         char *zMsg;
-        sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
-        zMsg = sqlite3MPrintf(pParse->db, "%s.%s may not be NULL",
+        sqlite3VdbeAddOp3(v, OP_HaltIfNull,
+                                  SQLITE_CONSTRAINT, onError, regData+i);
+        zMsg = sqlite3MPrintf(db, "%s.%s may not be NULL",
                               pTab->zName, pTab->aCol[i].zName);
         sqlite3VdbeChangeP4(v, -1, zMsg, P4_DYNAMIC);
         break;
       }
       case OE_Ignore: {
-        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
+        sqlite3VdbeAddOp2(v, OP_IsNull, regData+i, ignoreDest);
         break;
       }
-      case OE_Replace: {
+      default: {
+        assert( onError==OE_Replace );
+        j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regData+i);
         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regData+i);
+        sqlite3VdbeJumpHere(v, j1);
         break;
       }
     }
-    sqlite3VdbeJumpHere(v, j1);
   }
 
   /* Test all CHECK constraints
   */
 #ifndef SQLITE_OMIT_CHECK
-  if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
-    int allOk = sqlite3VdbeMakeLabel(v);
+  if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
+    ExprList *pCheck = pTab->pCheck;
     pParse->ckBase = regData;
-    sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, SQLITE_JUMPIFNULL);
     onError = overrideError!=OE_Default ? overrideError : OE_Abort;
-    if( onError==OE_Ignore ){
-      sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
-    }else{
-      sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
+    for(i=0; i<pCheck->nExpr; i++){
+      int allOk = sqlite3VdbeMakeLabel(v);
+      sqlite3ExprIfTrue(pParse, pCheck->a[i].pExpr, allOk, SQLITE_JUMPIFNULL);
+      if( onError==OE_Ignore ){
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
+      }else{
+        char *zConsName = pCheck->a[i].zName;
+        if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
+        if( zConsName ){
+          zConsName = sqlite3MPrintf(db, "constraint %s failed", zConsName);
+        }else{
+          zConsName = 0;
+        }
+        sqlite3HaltConstraint(pParse, onError, zConsName, P4_DYNAMIC);
+      }
+      sqlite3VdbeResolveLabel(v, allOk);
     }
-    sqlite3VdbeResolveLabel(v, allOk);
   }
 #endif /* !defined(SQLITE_OMIT_CHECK) */
 
@@ -68442,39 +89209,71 @@ SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
       onError = OE_Abort;
     }
     
-    if( onError!=OE_Replace || pTab->pIndex ){
-      if( isUpdate ){
-        j2 = sqlite3VdbeAddOp3(v, OP_Eq, regRowid, 0, regRowid-1);
+    if( isUpdate ){
+      j2 = sqlite3VdbeAddOp3(v, OP_Eq, regRowid, 0, rowidChng);
+    }
+    j3 = sqlite3VdbeAddOp3(v, OP_NotExists, baseCur, 0, regRowid);
+    switch( onError ){
+      default: {
+        onError = OE_Abort;
+        /* Fall thru into the next case */
       }
-      j3 = sqlite3VdbeAddOp3(v, OP_NotExists, baseCur, 0, regRowid);
-      switch( onError ){
-        default: {
-          onError = OE_Abort;
-          /* Fall thru into the next case */
+      case OE_Rollback:
+      case OE_Abort:
+      case OE_Fail: {
+        sqlite3HaltConstraint(
+          pParse, onError, "PRIMARY KEY must be unique", P4_STATIC);
+        break;
+      }
+      case OE_Replace: {
+        /* If there are DELETE triggers on this table and the
+        ** recursive-triggers flag is set, call GenerateRowDelete() to
+        ** remove the conflicting row from the table. This will fire
+        ** the triggers and remove both the table and index b-tree entries.
+        **
+        ** Otherwise, if there are no triggers or the recursive-triggers
+        ** flag is not set, but the table has one or more indexes, call 
+        ** GenerateRowIndexDelete(). This removes the index b-tree entries 
+        ** only. The table b-tree entry will be replaced by the new entry 
+        ** when it is inserted.  
+        **
+        ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
+        ** also invoke MultiWrite() to indicate that this VDBE may require
+        ** statement rollback (if the statement is aborted after the delete
+        ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
+        ** but being more selective here allows statements like:
+        **
+        **   REPLACE INTO t(rowid) VALUES($newrowid)
+        **
+        ** to run without a statement journal if there are no indexes on the
+        ** table.
+        */
+        Trigger *pTrigger = 0;
+        if( db->flags&SQLITE_RecTriggers ){
+          pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
         }
-        case OE_Rollback:
-        case OE_Abort:
-        case OE_Fail: {
-          sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0,
-                           "PRIMARY KEY must be unique", P4_STATIC);
-          break;
-        }
-        case OE_Replace: {
+        if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
+          sqlite3MultiWrite(pParse);
+          sqlite3GenerateRowDelete(
+              pParse, pTab, baseCur, regRowid, 0, pTrigger, OE_Replace
+          );
+        }else if( pTab->pIndex ){
+          sqlite3MultiWrite(pParse);
           sqlite3GenerateRowIndexDelete(pParse, pTab, baseCur, 0);
-          seenReplace = 1;
-          break;
-        }
-        case OE_Ignore: {
-          assert( seenReplace==0 );
-          sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
-          break;
         }
+        seenReplace = 1;
+        break;
       }
-      sqlite3VdbeJumpHere(v, j3);
-      if( isUpdate ){
-        sqlite3VdbeJumpHere(v, j2);
+      case OE_Ignore: {
+        assert( seenReplace==0 );
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
+        break;
       }
     }
+    sqlite3VdbeJumpHere(v, j3);
+    if( isUpdate ){
+      sqlite3VdbeJumpHere(v, j2);
+    }
   }
 
   /* Test all UNIQUE constraints by creating entries for each UNIQUE
@@ -68499,13 +89298,15 @@ SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
     }
     sqlite3VdbeAddOp2(v, OP_SCopy, regRowid, regIdx+i);
     sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn+1, aRegIdx[iCur]);
-    sqlite3IndexAffinityStr(v, pIdx);
+    sqlite3VdbeChangeP4(v, -1, sqlite3IndexAffinityStr(v, pIdx), P4_TRANSIENT);
     sqlite3ExprCacheAffinityChange(pParse, regIdx, pIdx->nColumn+1);
-    sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);
 
     /* Find out what action to take in case there is an indexing conflict */
     onError = pIdx->onError;
-    if( onError==OE_None ) continue;  /* pIdx is not a UNIQUE index */
+    if( onError==OE_None ){ 
+      sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);
+      continue;  /* pIdx is not a UNIQUE index */
+    }
     if( overrideError!=OE_Default ){
       onError = overrideError;
     }else if( onError==OE_Default ){
@@ -68516,14 +89317,13 @@ SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
       else if( onError==OE_Fail ) onError = OE_Abort;
     }
     
-
     /* Check to see if the new index entry will be unique */
-    j2 = sqlite3VdbeAddOp3(v, OP_IsNull, regIdx, 0, pIdx->nColumn);
     regR = sqlite3GetTempReg(pParse);
-    sqlite3VdbeAddOp2(v, OP_SCopy, regRowid-hasTwoRowids, regR);
+    sqlite3VdbeAddOp2(v, OP_SCopy, regOldRowid, regR);
     j3 = sqlite3VdbeAddOp4(v, OP_IsUnique, baseCur+iCur+1, 0,
-                           regR, SQLITE_INT_TO_PTR(aRegIdx[iCur]),
+                           regR, SQLITE_INT_TO_PTR(regIdx),
                            P4_INT32);
+    sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);
 
     /* Generate code that executes if the new index entry is not unique */
     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
@@ -68532,30 +89332,25 @@ SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
       case OE_Rollback:
       case OE_Abort:
       case OE_Fail: {
-        int j, n1, n2;
-        char zErrMsg[200];
-        sqlite3_snprintf(ArraySize(zErrMsg), zErrMsg,
-                         pIdx->nColumn>1 ? "columns " : "column ");
-        n1 = sqlite3Strlen30(zErrMsg);
-        for(j=0; j<pIdx->nColumn && n1<ArraySize(zErrMsg)-30; j++){
+        int j;
+        StrAccum errMsg;
+        const char *zSep;
+        char *zErr;
+
+        sqlite3StrAccumInit(&errMsg, 0, 0, 200);
+        errMsg.db = db;
+        zSep = pIdx->nColumn>1 ? "columns " : "column ";
+        for(j=0; j<pIdx->nColumn; j++){
           char *zCol = pTab->aCol[pIdx->aiColumn[j]].zName;
-          n2 = sqlite3Strlen30(zCol);
-          if( j>0 ){
-            sqlite3_snprintf(ArraySize(zErrMsg)-n1, &zErrMsg[n1], ", ");
-            n1 += 2;
-          }
-          if( n1+n2>ArraySize(zErrMsg)-30 ){
-            sqlite3_snprintf(ArraySize(zErrMsg)-n1, &zErrMsg[n1], "...");
-            n1 += 3;
-            break;
-          }else{
-            sqlite3_snprintf(ArraySize(zErrMsg)-n1, &zErrMsg[n1], "%s", zCol);
-            n1 += n2;
-          }
+          sqlite3StrAccumAppend(&errMsg, zSep, -1);
+          zSep = ", ";
+          sqlite3StrAccumAppend(&errMsg, zCol, -1);
         }
-        sqlite3_snprintf(ArraySize(zErrMsg)-n1, &zErrMsg[n1], 
-            pIdx->nColumn>1 ? " are not unique" : " is not unique");
-        sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0, zErrMsg,0);
+        sqlite3StrAccumAppend(&errMsg,
+            pIdx->nColumn>1 ? " are not unique" : " is not unique", -1);
+        zErr = sqlite3StrAccumFinish(&errMsg);
+        sqlite3HaltConstraint(pParse, onError, zErr, 0);
+        sqlite3DbFree(errMsg.db, zErr);
         break;
       }
       case OE_Ignore: {
@@ -68563,16 +89358,27 @@ SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
         sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
         break;
       }
-      case OE_Replace: {
-        sqlite3GenerateRowDelete(pParse, pTab, baseCur, regR, 0);
+      default: {
+        Trigger *pTrigger = 0;
+        assert( onError==OE_Replace );
+        sqlite3MultiWrite(pParse);
+        if( db->flags&SQLITE_RecTriggers ){
+          pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
+        }
+        sqlite3GenerateRowDelete(
+            pParse, pTab, baseCur, regR, 0, pTrigger, OE_Replace
+        );
         seenReplace = 1;
         break;
       }
     }
-    sqlite3VdbeJumpHere(v, j2);
     sqlite3VdbeJumpHere(v, j3);
     sqlite3ReleaseTempReg(pParse, regR);
   }
+  
+  if( pbMayReplace ){
+    *pbMayReplace = seenReplace;
+  }
 }
 
 /*
@@ -68591,8 +89397,8 @@ SQLITE_PRIVATE void sqlite3CompleteInsertion(
   int regRowid,       /* Range of content */
   int *aRegIdx,       /* Register used by each index.  0 for unused indices */
   int isUpdate,       /* True for UPDATE, False for INSERT */
-  int newIdx,         /* Index of NEW table for triggers.  -1 if none */
-  int appendBias      /* True if this is likely to be an append */
+  int appendBias,     /* True if this is likely to be an append */
+  int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
 ){
   int i;
   Vdbe *v;
@@ -68609,17 +89415,15 @@ SQLITE_PRIVATE void sqlite3CompleteInsertion(
   for(i=nIdx-1; i>=0; i--){
     if( aRegIdx[i]==0 ) continue;
     sqlite3VdbeAddOp2(v, OP_IdxInsert, baseCur+i+1, aRegIdx[i]);
+    if( useSeekResult ){
+      sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+    }
   }
   regData = regRowid + 1;
   regRec = sqlite3GetTempReg(pParse);
   sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
   sqlite3TableAffinityStr(v, pTab);
   sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
-#ifndef SQLITE_OMIT_TRIGGER
-  if( newIdx>=0 ){
-    sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRec, regRowid);
-  }
-#endif
   if( pParse->nested ){
     pik_flags = 0;
   }else{
@@ -68629,9 +89433,12 @@ SQLITE_PRIVATE void sqlite3CompleteInsertion(
   if( appendBias ){
     pik_flags |= OPFLAG_APPEND;
   }
+  if( useSeekResult ){
+    pik_flags |= OPFLAG_USESEEKRESULT;
+  }
   sqlite3VdbeAddOp3(v, OP_Insert, baseCur, regRec, regRowid);
   if( !pParse->nested ){
-    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
+    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_TRANSIENT);
   }
   sqlite3VdbeChangeP5(v, pik_flags);
 }
@@ -68666,7 +89473,7 @@ SQLITE_PRIVATE int sqlite3OpenTableAndIndices(
                       (char*)pKey, P4_KEYINFO_HANDOFF);
     VdbeComment((v, "%s", pIdx->zName));
   }
-  if( pParse->nTab<=baseCur+i ){
+  if( pParse->nTab<baseCur+i ){
     pParse->nTab = baseCur+i;
   }
   return i-1;
@@ -68726,7 +89533,7 @@ static int xferCompatibleIndex(Index *pDest, Index *pSrc){
     if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
       return 0;   /* Different sort orders */
     }
-    if( pSrc->azColl[i]!=pDest->azColl[i] ){
+    if( !xferCompatibleCollation(pSrc->azColl[i],pDest->azColl[i]) ){
       return 0;   /* Different collating sequences */
     }
   }
@@ -68740,31 +89547,25 @@ static int xferCompatibleIndex(Index *pDest, Index *pSrc){
 **
 **     INSERT INTO tab1 SELECT * FROM tab2;
 **
-** This optimization is only attempted if
+** The xfer optimization transfers raw records from tab2 over to tab1.  
+** Columns are not decoded and reassemblied, which greatly improves
+** performance.  Raw index records are transferred in the same way.
 **
-**    (1)  tab1 and tab2 have identical schemas including all the
-**         same indices and constraints
+** The xfer optimization is only attempted if tab1 and tab2 are compatible.
+** There are lots of rules for determining compatibility - see comments
+** embedded in the code for details.
 **
-**    (2)  tab1 and tab2 are different tables
+** This routine returns TRUE if the optimization is guaranteed to be used.
+** Sometimes the xfer optimization will only work if the destination table
+** is empty - a factor that can only be determined at run-time.  In that
+** case, this routine generates code for the xfer optimization but also
+** does a test to see if the destination table is empty and jumps over the
+** xfer optimization code if the test fails.  In that case, this routine
+** returns FALSE so that the caller will know to go ahead and generate
+** an unoptimized transfer.  This routine also returns FALSE if there
+** is no chance that the xfer optimization can be applied.
 **
-**    (3)  There must be no triggers on tab1
-**
-**    (4)  The result set of the SELECT statement is "*"
-**
-**    (5)  The SELECT statement has no WHERE, HAVING, ORDER BY, GROUP BY,
-**         or LIMIT clause.
-**
-**    (6)  The SELECT statement is a simple (not a compound) select that
-**         contains only tab2 in its FROM clause
-**
-** This method for implementing the INSERT transfers raw records from
-** tab2 over to tab1.  The columns are not decoded.  Raw records from
-** the indices of tab2 are transfered to tab1 as well.  In so doing,
-** the resulting tab1 has much less fragmentation.
-**
-** This routine returns TRUE if the optimization is attempted.  If any
-** of the conditions above fail so that the optimization should not
-** be attempted, then this routine returns FALSE.
+** This optimization is particularly useful at making VACUUM run faster.
 */
 static int xferOptimization(
   Parse *pParse,        /* Parser context */
@@ -68792,7 +89593,7 @@ static int xferOptimization(
   if( pSelect==0 ){
     return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
   }
-  if( pDest->pTrigger ){
+  if( sqlite3TriggerList(pParse, pDest) ){
     return 0;   /* tab1 must not have triggers */
   }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
@@ -68801,10 +89602,8 @@ static int xferOptimization(
   }
 #endif
   if( onError==OE_Default ){
-    onError = OE_Abort;
-  }
-  if( onError!=OE_Abort && onError!=OE_Rollback ){
-    return 0;   /* Cannot do OR REPLACE or OR IGNORE or OR FAIL */
+    if( pDest->iPKey>=0 ) onError = pDest->keyConf;
+    if( onError==OE_Default ) onError = OE_Abort;
   }
   assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
   if( pSelect->pSrc->nSrc!=1 ){
@@ -68893,18 +89692,29 @@ static int xferOptimization(
     }
   }
 #ifndef SQLITE_OMIT_CHECK
-  if( pDest->pCheck && !sqlite3ExprCompare(pSrc->pCheck, pDest->pCheck) ){
+  if( pDest->pCheck && sqlite3ExprListCompare(pSrc->pCheck, pDest->pCheck) ){
     return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
   }
 #endif
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  /* Disallow the transfer optimization if the destination table constains
+  ** any foreign key constraints.  This is more restrictive than necessary.
+  ** But the main beneficiary of the transfer optimization is the VACUUM 
+  ** command, and the VACUUM command disables foreign key constraints.  So
+  ** the extra complication to make this rule less restrictive is probably
+  ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
+  */
+  if( (pParse->db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
+    return 0;
+  }
+#endif
+  if( (pParse->db->flags & SQLITE_CountRows)!=0 ){
+    return 0;  /* xfer opt does not play well with PRAGMA count_changes */
+  }
 
-  /* If we get this far, it means either:
-  **
-  **    *   We can always do the transfer if the table contains an
-  **        an integer primary key
-  **
-  **    *   We can conditionally do the transfer if the destination
-  **        table is empty.
+  /* If we get this far, it means that the xfer optimization is at
+  ** least a possibility, though it might only work if the destination
+  ** table (tab1) is initially empty.
   */
 #ifdef SQLITE_TEST
   sqlite3_xferopt_count++;
@@ -68916,16 +89726,23 @@ static int xferOptimization(
   iDest = pParse->nTab++;
   regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
   sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
-  if( (pDest->iPKey<0 && pDest->pIndex!=0) || destHasUniqueIdx ){
-    /* If tables do not have an INTEGER PRIMARY KEY and there
-    ** are indices to be copied and the destination is not empty,
-    ** we have to disallow the transfer optimization because the
-    ** the rowids might change which will mess up indexing.
+  if( (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
+   || destHasUniqueIdx                              /* (2) */
+   || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
+  ){
+    /* In some circumstances, we are able to run the xfer optimization
+    ** only if the destination table is initially empty.  This code makes
+    ** that determination.  Conditions under which the destination must
+    ** be empty:
     **
-    ** Or if the destination has a UNIQUE index and is not empty,
-    ** we also disallow the transfer optimization because we cannot
-    ** insure that all entries in the union of DEST and SRC will be
-    ** unique.
+    ** (1) There is no INTEGER PRIMARY KEY but there are indices.
+    **     (If the destination is not initially empty, the rowid fields
+    **     of index entries might need to change.)
+    **
+    ** (2) The destination has a unique index.  (The xfer optimization 
+    **     is unable to test uniqueness.)
+    **
+    ** (3) onError is something other than OE_Abort and OE_Rollback.
     */
     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0);
     emptyDestTest = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
@@ -68940,8 +89757,8 @@ static int xferOptimization(
   if( pDest->iPKey>=0 ){
     addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
     addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
-    sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0,
-                      "PRIMARY KEY must be unique", P4_STATIC);
+    sqlite3HaltConstraint(
+        pParse, onError, "PRIMARY KEY must be unique", P4_STATIC);
     sqlite3VdbeJumpHere(v, addr2);
     autoIncStep(pParse, regAutoinc, regRowid);
   }else if( pDest->pIndex==0 ){
@@ -68955,9 +89772,8 @@ static int xferOptimization(
   sqlite3VdbeChangeP5(v, OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND);
   sqlite3VdbeChangeP4(v, -1, pDest->zName, 0);
   sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1);
-  autoIncEnd(pParse, iDbDest, pDest, regAutoinc);
   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
-    for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
+    for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
     }
     assert( pSrcIdx );
@@ -68993,11 +89809,6 @@ static int xferOptimization(
 }
 #endif /* SQLITE_OMIT_XFER_OPT */
 
-/* Make sure "isView" gets undefined in case this file becomes part of
-** the amalgamation - so that subsequent files do not see isView as a
-** macro. */
-#undef isView
-
 /************** End of insert.c **********************************************/
 /************** Begin file legacy.c ******************************************/
 /*
@@ -69015,8 +89826,6 @@ static int xferOptimization(
 ** implement the programmer interface to the library.  Routines in
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
@@ -69037,14 +89846,14 @@ SQLITE_API int sqlite3_exec(
   void *pArg,                 /* First argument to xCallback() */
   char **pzErrMsg             /* Write error messages here */
 ){
-  int rc = SQLITE_OK;
-  const char *zLeftover;
-  sqlite3_stmt *pStmt = 0;
-  char **azCols = 0;
-
-  int nRetry = 0;
-  int nCallback;
+  int rc = SQLITE_OK;         /* Return code */
+  const char *zLeftover;      /* Tail of unprocessed SQL */
+  sqlite3_stmt *pStmt = 0;    /* The current SQL statement */
+  char **azCols = 0;          /* Names of result columns */
+  int nRetry = 0;             /* Number of retry attempts */
+  int callbackIsInit;         /* True if callback data is initialized */
 
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
   if( zSql==0 ) zSql = "";
 
   sqlite3_mutex_enter(db->mutex);
@@ -69065,7 +89874,7 @@ SQLITE_API int sqlite3_exec(
       continue;
     }
 
-    nCallback = 0;
+    callbackIsInit = 0;
     nCol = sqlite3_column_count(pStmt);
 
     while( 1 ){
@@ -69074,13 +89883,12 @@ SQLITE_API int sqlite3_exec(
 
       /* Invoke the callback function if required */
       if( xCallback && (SQLITE_ROW==rc || 
-          (SQLITE_DONE==rc && !nCallback && db->flags&SQLITE_NullCallback)) ){
-        if( 0==nCallback ){
+          (SQLITE_DONE==rc && !callbackIsInit
+                           && db->flags&SQLITE_NullCallback)) ){
+        if( !callbackIsInit ){
+          azCols = sqlite3DbMallocZero(db, 2*nCol*sizeof(const char*) + 1);
           if( azCols==0 ){
-            azCols = sqlite3DbMallocZero(db, 2*nCol*sizeof(const char*) + 1);
-            if( azCols==0 ){
-              goto exec_out;
-            }
+            goto exec_out;
           }
           for(i=0; i<nCol; i++){
             azCols[i] = (char *)sqlite3_column_name(pStmt, i);
@@ -69088,7 +89896,7 @@ SQLITE_API int sqlite3_exec(
             ** strings so there is no way for sqlite3_column_name() to fail. */
             assert( azCols[i]!=0 );
           }
-          nCallback++;
+          callbackIsInit = 1;
         }
         if( rc==SQLITE_ROW ){
           azVals = &azCols[nCol];
@@ -69102,7 +89910,7 @@ SQLITE_API int sqlite3_exec(
         }
         if( xCallback(pArg, nCol, azVals, azCols) ){
           rc = SQLITE_ABORT;
-          sqlite3_finalize(pStmt);
+          sqlite3VdbeFinalize((Vdbe *)pStmt);
           pStmt = 0;
           sqlite3Error(db, SQLITE_ABORT, 0);
           goto exec_out;
@@ -69110,12 +89918,12 @@ SQLITE_API int sqlite3_exec(
       }
 
       if( rc!=SQLITE_ROW ){
-        rc = sqlite3_finalize(pStmt);
+        rc = sqlite3VdbeFinalize((Vdbe *)pStmt);
         pStmt = 0;
         if( rc!=SQLITE_SCHEMA ){
           nRetry = 0;
           zSql = zLeftover;
-          while( isspace((unsigned char)zSql[0]) ) zSql++;
+          while( sqlite3Isspace(zSql[0]) ) zSql++;
         }
         break;
       }
@@ -69126,15 +89934,18 @@ SQLITE_API int sqlite3_exec(
   }
 
 exec_out:
-  if( pStmt ) sqlite3_finalize(pStmt);
+  if( pStmt ) sqlite3VdbeFinalize((Vdbe *)pStmt);
   sqlite3DbFree(db, azCols);
 
   rc = sqlite3ApiExit(db, rc);
-  if( rc!=SQLITE_OK && rc==sqlite3_errcode(db) && pzErrMsg ){
+  if( rc!=SQLITE_OK && ALWAYS(rc==sqlite3_errcode(db)) && pzErrMsg ){
     int nErrMsg = 1 + sqlite3Strlen30(sqlite3_errmsg(db));
     *pzErrMsg = sqlite3Malloc(nErrMsg);
     if( *pzErrMsg ){
       memcpy(*pzErrMsg, sqlite3_errmsg(db), nErrMsg);
+    }else{
+      rc = SQLITE_NOMEM;
+      sqlite3Error(db, SQLITE_NOMEM, 0);
     }
   }else if( pzErrMsg ){
     *pzErrMsg = 0;
@@ -69160,8 +89971,6 @@ exec_out:
 *************************************************************************
 ** This file contains code used to dynamically load extensions into
 ** the SQLite library.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 #ifndef SQLITE_CORE
@@ -69185,8 +89994,6 @@ exec_out:
 ** an SQLite instance.  Shared libraries that intend to be loaded
 ** as extensions by SQLite should #include this file instead of 
 ** sqlite3.h.
-**
-** @(#) $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef _SQLITE3EXT_H_
 #define _SQLITE3EXT_H_
@@ -69221,8 +90028,10 @@ struct sqlite3_api_routines {
   int  (*busy_timeout)(sqlite3*,int ms);
   int  (*changes)(sqlite3*);
   int  (*close)(sqlite3*);
-  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,int eTextRep,const char*));
-  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,int eTextRep,const void*));
+  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                           int eTextRep,const char*));
+  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                             int eTextRep,const void*));
   const void * (*column_blob)(sqlite3_stmt*,int iCol);
   int  (*column_bytes)(sqlite3_stmt*,int iCol);
   int  (*column_bytes16)(sqlite3_stmt*,int iCol);
@@ -69247,10 +90056,18 @@ struct sqlite3_api_routines {
   void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
   int  (*complete)(const char*sql);
   int  (*complete16)(const void*sql);
-  int  (*create_collation)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*));
-  int  (*create_collation16)(sqlite3*,const void*,int,void*,int(*)(void*,int,const void*,int,const void*));
-  int  (*create_function)(sqlite3*,const char*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
-  int  (*create_function16)(sqlite3*,const void*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
+  int  (*create_collation)(sqlite3*,const char*,int,void*,
+                           int(*)(void*,int,const void*,int,const void*));
+  int  (*create_collation16)(sqlite3*,const void*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*));
+  int  (*create_function)(sqlite3*,const char*,int,int,void*,
+                          void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xFinal)(sqlite3_context*));
+  int  (*create_function16)(sqlite3*,const void*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*));
   int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
   int  (*data_count)(sqlite3_stmt*pStmt);
   sqlite3 * (*db_handle)(sqlite3_stmt*);
@@ -69295,16 +90112,19 @@ struct sqlite3_api_routines {
   void  (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
   void  (*result_value)(sqlite3_context*,sqlite3_value*);
   void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
-  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,const char*,const char*),void*);
+  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,
+                         const char*,const char*),void*);
   void  (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
   char * (*snprintf)(int,char*,const char*,...);
   int  (*step)(sqlite3_stmt*);
-  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,char const**,char const**,int*,int*,int*);
+  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,
+                                char const**,char const**,int*,int*,int*);
   void  (*thread_cleanup)(void);
   int  (*total_changes)(sqlite3*);
   void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
   int  (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
-  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,sqlite_int64),void*);
+  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,
+                                         sqlite_int64),void*);
   void * (*user_data)(sqlite3_context*);
   const void * (*value_blob)(sqlite3_value*);
   int  (*value_bytes)(sqlite3_value*);
@@ -69326,15 +90146,19 @@ struct sqlite3_api_routines {
   int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
   int (*clear_bindings)(sqlite3_stmt*);
   /* Added by 3.4.1 */
-  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,void (*xDestroy)(void *));
+  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,
+                          void (*xDestroy)(void *));
   /* Added by 3.5.0 */
   int (*bind_zeroblob)(sqlite3_stmt*,int,int);
   int (*blob_bytes)(sqlite3_blob*);
   int (*blob_close)(sqlite3_blob*);
-  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,int,sqlite3_blob**);
+  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,
+                   int,sqlite3_blob**);
   int (*blob_read)(sqlite3_blob*,void*,int,int);
   int (*blob_write)(sqlite3_blob*,const void*,int,int);
-  int (*create_collation_v2)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*),void(*)(void*));
+  int (*create_collation_v2)(sqlite3*,const char*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*),
+                             void(*)(void*));
   int (*file_control)(sqlite3*,const char*,int,void*);
   sqlite3_int64 (*memory_highwater)(int);
   sqlite3_int64 (*memory_used)(void);
@@ -69363,6 +90187,34 @@ struct sqlite3_api_routines {
   sqlite3_stmt *(*next_stmt)(sqlite3*,sqlite3_stmt*);
   const char *(*sql)(sqlite3_stmt*);
   int (*status)(int,int*,int*,int);
+  int (*backup_finish)(sqlite3_backup*);
+  sqlite3_backup *(*backup_init)(sqlite3*,const char*,sqlite3*,const char*);
+  int (*backup_pagecount)(sqlite3_backup*);
+  int (*backup_remaining)(sqlite3_backup*);
+  int (*backup_step)(sqlite3_backup*,int);
+  const char *(*compileoption_get)(int);
+  int (*compileoption_used)(const char*);
+  int (*create_function_v2)(sqlite3*,const char*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void(*xDestroy)(void*));
+  int (*db_config)(sqlite3*,int,...);
+  sqlite3_mutex *(*db_mutex)(sqlite3*);
+  int (*db_status)(sqlite3*,int,int*,int*,int);
+  int (*extended_errcode)(sqlite3*);
+  void (*log)(int,const char*,...);
+  sqlite3_int64 (*soft_heap_limit64)(sqlite3_int64);
+  const char *(*sourceid)(void);
+  int (*stmt_status)(sqlite3_stmt*,int,int);
+  int (*strnicmp)(const char*,const char*,int);
+  int (*unlock_notify)(sqlite3*,void(*)(void**,int),void*);
+  int (*wal_autocheckpoint)(sqlite3*,int);
+  int (*wal_checkpoint)(sqlite3*,const char*);
+  void *(*wal_hook)(sqlite3*,int(*)(void*,sqlite3*,const char*,int),void*);
+  int (*blob_reopen)(sqlite3_blob*,sqlite3_int64);
+  int (*vtab_config)(sqlite3*,int op,...);
+  int (*vtab_on_conflict)(sqlite3*);
 };
 
 /*
@@ -69542,6 +90394,30 @@ struct sqlite3_api_routines {
 #define sqlite3_next_stmt              sqlite3_api->next_stmt
 #define sqlite3_sql                    sqlite3_api->sql
 #define sqlite3_status                 sqlite3_api->status
+#define sqlite3_backup_finish          sqlite3_api->backup_finish
+#define sqlite3_backup_init            sqlite3_api->backup_init
+#define sqlite3_backup_pagecount       sqlite3_api->backup_pagecount
+#define sqlite3_backup_remaining       sqlite3_api->backup_remaining
+#define sqlite3_backup_step            sqlite3_api->backup_step
+#define sqlite3_compileoption_get      sqlite3_api->compileoption_get
+#define sqlite3_compileoption_used     sqlite3_api->compileoption_used
+#define sqlite3_create_function_v2     sqlite3_api->create_function_v2
+#define sqlite3_db_config              sqlite3_api->db_config
+#define sqlite3_db_mutex               sqlite3_api->db_mutex
+#define sqlite3_db_status              sqlite3_api->db_status
+#define sqlite3_extended_errcode       sqlite3_api->extended_errcode
+#define sqlite3_log                    sqlite3_api->log
+#define sqlite3_soft_heap_limit64      sqlite3_api->soft_heap_limit64
+#define sqlite3_sourceid               sqlite3_api->sourceid
+#define sqlite3_stmt_status            sqlite3_api->stmt_status
+#define sqlite3_strnicmp               sqlite3_api->strnicmp
+#define sqlite3_unlock_notify          sqlite3_api->unlock_notify
+#define sqlite3_wal_autocheckpoint     sqlite3_api->wal_autocheckpoint
+#define sqlite3_wal_checkpoint         sqlite3_api->wal_checkpoint
+#define sqlite3_wal_hook               sqlite3_api->wal_hook
+#define sqlite3_blob_reopen            sqlite3_api->blob_reopen
+#define sqlite3_vtab_config            sqlite3_api->vtab_config
+#define sqlite3_vtab_on_conflict       sqlite3_api->vtab_on_conflict
 #endif /* SQLITE_CORE */
 
 #define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api = 0;
@@ -69551,6 +90427,7 @@ struct sqlite3_api_routines {
 
 /************** End of sqlite3ext.h ******************************************/
 /************** Continuing where we left off in loadext.c ********************/
+/* #include <string.h> */
 
 #ifndef SQLITE_OMIT_LOAD_EXTENSION
 
@@ -69603,6 +90480,11 @@ struct sqlite3_api_routines {
 # define sqlite3_complete16 0
 #endif
 
+#ifdef SQLITE_OMIT_DECLTYPE
+# define sqlite3_column_decltype16      0
+# define sqlite3_column_decltype        0
+#endif
+
 #ifdef SQLITE_OMIT_PROGRESS_CALLBACK
 # define sqlite3_progress_handler 0
 #endif
@@ -69611,6 +90493,8 @@ struct sqlite3_api_routines {
 # define sqlite3_create_module 0
 # define sqlite3_create_module_v2 0
 # define sqlite3_declare_vtab 0
+# define sqlite3_vtab_config 0
+# define sqlite3_vtab_on_conflict 0
 #endif
 
 #ifdef SQLITE_OMIT_SHARED_CACHE
@@ -69634,6 +90518,7 @@ struct sqlite3_api_routines {
 #define sqlite3_blob_open      0
 #define sqlite3_blob_read      0
 #define sqlite3_blob_write     0
+#define sqlite3_blob_reopen    0
 #endif
 
 /*
@@ -69859,6 +90744,49 @@ static const sqlite3_api_routines sqlite3Apis = {
   sqlite3_next_stmt,
   sqlite3_sql,
   sqlite3_status,
+
+  /*
+  ** Added for 3.7.4
+  */
+  sqlite3_backup_finish,
+  sqlite3_backup_init,
+  sqlite3_backup_pagecount,
+  sqlite3_backup_remaining,
+  sqlite3_backup_step,
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+  sqlite3_compileoption_get,
+  sqlite3_compileoption_used,
+#else
+  0,
+  0,
+#endif
+  sqlite3_create_function_v2,
+  sqlite3_db_config,
+  sqlite3_db_mutex,
+  sqlite3_db_status,
+  sqlite3_extended_errcode,
+  sqlite3_log,
+  sqlite3_soft_heap_limit64,
+  sqlite3_sourceid,
+  sqlite3_stmt_status,
+  sqlite3_strnicmp,
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  sqlite3_unlock_notify,
+#else
+  0,
+#endif
+#ifndef SQLITE_OMIT_WAL
+  sqlite3_wal_autocheckpoint,
+  sqlite3_wal_checkpoint,
+  sqlite3_wal_hook,
+#else
+  0,
+  0,
+  0,
+#endif
+  sqlite3_blob_reopen,
+  sqlite3_vtab_config,
+  sqlite3_vtab_on_conflict,
 };
 
 /*
@@ -69884,6 +90812,9 @@ static int sqlite3LoadExtension(
   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
   char *zErrmsg = 0;
   void **aHandle;
+  int nMsg = 300 + sqlite3Strlen30(zFile);
+
+  if( pzErrMsg ) *pzErrMsg = 0;
 
   /* Ticket #1863.  To avoid a creating security problems for older
   ** applications that relink against newer versions of SQLite, the
@@ -69905,12 +90836,12 @@ static int sqlite3LoadExtension(
   handle = sqlite3OsDlOpen(pVfs, zFile);
   if( handle==0 ){
     if( pzErrMsg ){
-      char zErr[256];
-      zErr[sizeof(zErr)-1] = '\0';
-      sqlite3_snprintf(sizeof(zErr)-1, zErr, 
-          "unable to open shared library [%s]", zFile);
-      sqlite3OsDlError(pVfs, sizeof(zErr)-1, zErr);
-      *pzErrMsg = sqlite3DbStrDup(0, zErr);
+      *pzErrMsg = zErrmsg = sqlite3_malloc(nMsg);
+      if( zErrmsg ){
+        sqlite3_snprintf(nMsg, zErrmsg, 
+            "unable to open shared library [%s]", zFile);
+        sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
+      }
     }
     return SQLITE_ERROR;
   }
@@ -69918,12 +90849,13 @@ static int sqlite3LoadExtension(
                    sqlite3OsDlSym(pVfs, handle, zProc);
   if( xInit==0 ){
     if( pzErrMsg ){
-      char zErr[256];
-      zErr[sizeof(zErr)-1] = '\0';
-      sqlite3_snprintf(sizeof(zErr)-1, zErr,
-          "no entry point [%s] in shared library [%s]", zProc,zFile);
-      sqlite3OsDlError(pVfs, sizeof(zErr)-1, zErr);
-      *pzErrMsg = sqlite3DbStrDup(0, zErr);
+      nMsg += sqlite3Strlen30(zProc);
+      *pzErrMsg = zErrmsg = sqlite3_malloc(nMsg);
+      if( zErrmsg ){
+        sqlite3_snprintf(nMsg, zErrmsg,
+            "no entry point [%s] in shared library [%s]", zProc,zFile);
+        sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
+      }
       sqlite3OsDlClose(pVfs, handle);
     }
     return SQLITE_ERROR;
@@ -69959,6 +90891,7 @@ SQLITE_API int sqlite3_load_extension(
   int rc;
   sqlite3_mutex_enter(db->mutex);
   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
+  rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
 }
@@ -70095,20 +91028,22 @@ SQLITE_API void sqlite3_reset_auto_extension(void){
 
 /*
 ** Load all automatic extensions.
+**
+** If anything goes wrong, set an error in the database connection.
 */
-SQLITE_PRIVATE int sqlite3AutoLoadExtensions(sqlite3 *db){
+SQLITE_PRIVATE void sqlite3AutoLoadExtensions(sqlite3 *db){
   int i;
   int go = 1;
-  int rc = SQLITE_OK;
+  int rc;
   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
 
   wsdAutoextInit;
   if( wsdAutoext.nExt==0 ){
     /* Common case: early out without every having to acquire a mutex */
-    return SQLITE_OK;
+    return;
   }
   for(i=0; go; i++){
-    char *zErrmsg = 0;
+    char *zErrmsg;
 #if SQLITE_THREADSAFE
     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 #endif
@@ -70121,15 +91056,14 @@ SQLITE_PRIVATE int sqlite3AutoLoadExtensions(sqlite3 *db){
               wsdAutoext.aExt[i];
     }
     sqlite3_mutex_leave(mutex);
-    if( xInit && xInit(db, &zErrmsg, &sqlite3Apis) ){
-      sqlite3Error(db, SQLITE_ERROR,
+    zErrmsg = 0;
+    if( xInit && (rc = xInit(db, &zErrmsg, &sqlite3Apis))!=0 ){
+      sqlite3Error(db, rc,
             "automatic extension loading failed: %s", zErrmsg);
       go = 0;
-      rc = SQLITE_ERROR;
-      sqlite3_free(zErrmsg);
     }
+    sqlite3_free(zErrmsg);
   }
-  return rc;
 }
 
 /************** End of loadext.c *********************************************/
@@ -70146,50 +91080,51 @@ SQLITE_PRIVATE int sqlite3AutoLoadExtensions(sqlite3 *db){
 **
 *************************************************************************
 ** This file contains code used to implement the PRAGMA command.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
-/* Ignore this whole file if pragmas are disabled
-*/
-#if !defined(SQLITE_OMIT_PRAGMA) && !defined(SQLITE_OMIT_PARSER)
-
 /*
 ** Interpret the given string as a safety level.  Return 0 for OFF,
 ** 1 for ON or NORMAL and 2 for FULL.  Return 1 for an empty or 
-** unrecognized string argument.
+** unrecognized string argument.  The FULL option is disallowed
+** if the omitFull parameter it 1.
 **
 ** Note that the values returned are one less that the values that
 ** should be passed into sqlite3BtreeSetSafetyLevel().  The is done
 ** to support legacy SQL code.  The safety level used to be boolean
 ** and older scripts may have used numbers 0 for OFF and 1 for ON.
 */
-static u8 getSafetyLevel(const char *z){
+static u8 getSafetyLevel(const char *z, int omitFull, int dflt){
                              /* 123456789 123456789 */
   static const char zText[] = "onoffalseyestruefull";
   static const u8 iOffset[] = {0, 1, 2, 4, 9, 12, 16};
   static const u8 iLength[] = {2, 2, 3, 5, 3, 4, 4};
   static const u8 iValue[] =  {1, 0, 0, 0, 1, 1, 2};
   int i, n;
-  if( isdigit(*z) ){
-    return (u8)atoi(z);
+  if( sqlite3Isdigit(*z) ){
+    return (u8)sqlite3Atoi(z);
   }
   n = sqlite3Strlen30(z);
-  for(i=0; i<ArraySize(iLength); i++){
+  for(i=0; i<ArraySize(iLength)-omitFull; i++){
     if( iLength[i]==n && sqlite3StrNICmp(&zText[iOffset[i]],z,n)==0 ){
       return iValue[i];
     }
   }
-  return 1;
+  return dflt;
 }
 
 /*
 ** Interpret the given string as a boolean value.
 */
-static u8 getBoolean(const char *z){
-  return getSafetyLevel(z)&1;
+SQLITE_PRIVATE u8 sqlite3GetBoolean(const char *z, int dflt){
+  return getSafetyLevel(z,1,dflt)!=0;
 }
 
+/* The sqlite3GetBoolean() function is used by other modules but the
+** remainder of this file is specific to PRAGMA processing.  So omit
+** the rest of the file if PRAGMAs are omitted from the build.
+*/
+#if !defined(SQLITE_OMIT_PRAGMA)
+
 /*
 ** Interpret the given string as a locking mode value.
 */
@@ -70213,7 +91148,7 @@ static int getAutoVacuum(const char *z){
   if( 0==sqlite3StrICmp(z, "none") ) return BTREE_AUTOVACUUM_NONE;
   if( 0==sqlite3StrICmp(z, "full") ) return BTREE_AUTOVACUUM_FULL;
   if( 0==sqlite3StrICmp(z, "incremental") ) return BTREE_AUTOVACUUM_INCR;
-  i = atoi(z);
+  i = sqlite3Atoi(z);
   return (u8)((i>=0&&i<=2)?i:0);
 }
 #endif /* ifndef SQLITE_OMIT_AUTOVACUUM */
@@ -70252,7 +91187,7 @@ static int invalidateTempStorage(Parse *pParse){
     }
     sqlite3BtreeClose(db->aDb[1].pBt);
     db->aDb[1].pBt = 0;
-    sqlite3ResetInternalSchema(db, 0);
+    sqlite3ResetAllSchemasOfConnection(db);
   }
   return SQLITE_OK;
 }
@@ -70279,14 +91214,16 @@ static int changeTempStorage(Parse *pParse, const char *zStorageType){
 /*
 ** Generate code to return a single integer value.
 */
-static void returnSingleInt(Parse *pParse, const char *zLabel, int value){
+static void returnSingleInt(Parse *pParse, const char *zLabel, i64 value){
   Vdbe *v = sqlite3GetVdbe(pParse);
   int mem = ++pParse->nMem;
-  sqlite3VdbeAddOp2(v, OP_Integer, value, mem);
-  if( pParse->explain==0 ){
-    sqlite3VdbeSetNumCols(v, 1);
-    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zLabel, SQLITE_STATIC);
+  i64 *pI64 = sqlite3DbMallocRaw(pParse->db, sizeof(value));
+  if( pI64 ){
+    memcpy(pI64, &value, sizeof(value));
   }
+  sqlite3VdbeAddOp4(v, OP_Int64, 0, mem, 0, (char*)pI64, P4_INT64);
+  sqlite3VdbeSetNumCols(v, 1);
+  sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zLabel, SQLITE_STATIC);
   sqlite3VdbeAddOp2(v, OP_ResultRow, mem, 1);
 }
 
@@ -70307,6 +91244,11 @@ static int flagPragma(Parse *pParse, const char *zLeft, const char *zRight){
     { "empty_result_callbacks",   SQLITE_NullCallback  },
     { "legacy_file_format",       SQLITE_LegacyFileFmt },
     { "fullfsync",                SQLITE_FullFSync     },
+    { "checkpoint_fullfsync",     SQLITE_CkptFullFSync },
+    { "reverse_unordered_selects", SQLITE_ReverseOrder  },
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+    { "automatic_index",          SQLITE_AutoIndex     },
+#endif
 #ifdef SQLITE_DEBUG
     { "sql_trace",                SQLITE_SqlTrace      },
     { "vdbe_listing",             SQLITE_VdbeListing   },
@@ -70317,11 +91259,17 @@ static int flagPragma(Parse *pParse, const char *zLeft, const char *zRight){
 #endif
     /* The following is VERY experimental */
     { "writable_schema",          SQLITE_WriteSchema|SQLITE_RecoveryMode },
-    { "omit_readlock",            SQLITE_NoReadlock    },
 
     /* TODO: Maybe it shouldn't be possible to change the ReadUncommitted
     ** flag if there are any active statements. */
     { "read_uncommitted",         SQLITE_ReadUncommitted },
+    { "recursive_triggers",       SQLITE_RecTriggers },
+
+    /* This flag may only be set if both foreign-key and trigger support
+    ** are present in the build.  */
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+    { "foreign_keys",             SQLITE_ForeignKeys },
+#endif
   };
   int i;
   const struct sPragmaType *p;
@@ -70335,10 +91283,17 @@ static int flagPragma(Parse *pParse, const char *zLeft, const char *zRight){
         if( zRight==0 ){
           returnSingleInt(pParse, p->zName, (db->flags & p->mask)!=0 );
         }else{
-          if( getBoolean(zRight) ){
-            db->flags |= p->mask;
+          int mask = p->mask;          /* Mask of bits to set or clear. */
+          if( db->autoCommit==0 ){
+            /* Foreign key support may not be enabled or disabled while not
+            ** in auto-commit mode.  */
+            mask &= ~(SQLITE_ForeignKeys);
+          }
+
+          if( sqlite3GetBoolean(zRight, 0) ){
+            db->flags |= mask;
           }else{
-            db->flags &= ~p->mask;
+            db->flags &= ~mask;
           }
 
           /* Many of the flag-pragmas modify the code generated by the SQL 
@@ -70359,17 +91314,45 @@ static int flagPragma(Parse *pParse, const char *zLeft, const char *zRight){
 /*
 ** Return a human-readable name for a constraint resolution action.
 */
+#ifndef SQLITE_OMIT_FOREIGN_KEY
 static const char *actionName(u8 action){
   const char *zName;
   switch( action ){
-    case OE_SetNull:  zName = "SET NULL";            break;
-    case OE_SetDflt:  zName = "SET DEFAULT";         break;
-    case OE_Cascade:  zName = "CASCADE";             break;
-    default:          zName = "RESTRICT";  
-                      assert( action==OE_Restrict ); break;
+    case OE_SetNull:  zName = "SET NULL";        break;
+    case OE_SetDflt:  zName = "SET DEFAULT";     break;
+    case OE_Cascade:  zName = "CASCADE";         break;
+    case OE_Restrict: zName = "RESTRICT";        break;
+    default:          zName = "NO ACTION";  
+                      assert( action==OE_None ); break;
   }
   return zName;
 }
+#endif
+
+
+/*
+** Parameter eMode must be one of the PAGER_JOURNALMODE_XXX constants
+** defined in pager.h. This function returns the associated lowercase
+** journal-mode name.
+*/
+SQLITE_PRIVATE const char *sqlite3JournalModename(int eMode){
+  static char * const azModeName[] = {
+    "delete", "persist", "off", "truncate", "memory"
+#ifndef SQLITE_OMIT_WAL
+     , "wal"
+#endif
+  };
+  assert( PAGER_JOURNALMODE_DELETE==0 );
+  assert( PAGER_JOURNALMODE_PERSIST==1 );
+  assert( PAGER_JOURNALMODE_OFF==2 );
+  assert( PAGER_JOURNALMODE_TRUNCATE==3 );
+  assert( PAGER_JOURNALMODE_MEMORY==4 );
+  assert( PAGER_JOURNALMODE_WAL==5 );
+  assert( eMode>=0 && eMode<=ArraySize(azModeName) );
+
+  if( eMode==ArraySize(azModeName) ) return 0;
+  return azModeName[eMode];
+}
 
 /*
 ** Process a pragma statement.  
@@ -70398,10 +91381,14 @@ SQLITE_PRIVATE void sqlite3Pragma(
   const char *zDb = 0;   /* The database name */
   Token *pId;            /* Pointer to <id> token */
   int iDb;               /* Database index for <database> */
-  sqlite3 *db = pParse->db;
-  Db *pDb;
-  Vdbe *v = pParse->pVdbe = sqlite3VdbeCreate(db);
+  char *aFcntl[4];       /* Argument to SQLITE_FCNTL_PRAGMA */
+  int rc;                      /* return value form SQLITE_FCNTL_PRAGMA */
+  sqlite3 *db = pParse->db;    /* The database connection */
+  Db *pDb;                     /* The specific database being pragmaed */
+  Vdbe *v = pParse->pVdbe = sqlite3VdbeCreate(db);  /* Prepared statement */
+
   if( v==0 ) return;
+  sqlite3VdbeRunOnlyOnce(v);
   pParse->nMem = 2;
 
   /* Interpret the [database.] part of the pragma statement. iDb is the
@@ -70430,8 +91417,36 @@ SQLITE_PRIVATE void sqlite3Pragma(
   if( sqlite3AuthCheck(pParse, SQLITE_PRAGMA, zLeft, zRight, zDb) ){
     goto pragma_out;
   }
+
+  /* Send an SQLITE_FCNTL_PRAGMA file-control to the underlying VFS
+  ** connection.  If it returns SQLITE_OK, then assume that the VFS
+  ** handled the pragma and generate a no-op prepared statement.
+  */
+  aFcntl[0] = 0;
+  aFcntl[1] = zLeft;
+  aFcntl[2] = zRight;
+  aFcntl[3] = 0;
+  rc = sqlite3_file_control(db, zDb, SQLITE_FCNTL_PRAGMA, (void*)aFcntl);
+  if( rc==SQLITE_OK ){
+    if( aFcntl[0] ){
+      int mem = ++pParse->nMem;
+      sqlite3VdbeAddOp4(v, OP_String8, 0, mem, 0, aFcntl[0], 0);
+      sqlite3VdbeSetNumCols(v, 1);
+      sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "result", SQLITE_STATIC);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, mem, 1);
+      sqlite3_free(aFcntl[0]);
+    }
+  }else if( rc!=SQLITE_NOTFOUND ){
+    if( aFcntl[0] ){
+      sqlite3ErrorMsg(pParse, "%s", aFcntl[0]);
+      sqlite3_free(aFcntl[0]);
+    }
+    pParse->nErr++;
+    pParse->rc = rc;
+  }else
+                            
  
-#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
   /*
   **  PRAGMA [database.]default_cache_size
   **  PRAGMA [database.]default_cache_size=N
@@ -70442,20 +91457,21 @@ SQLITE_PRIVATE void sqlite3Pragma(
   ** page cache size value and the persistent page cache size value
   ** stored in the database file.
   **
-  ** The default cache size is stored in meta-value 2 of page 1 of the
-  ** database file.  The cache size is actually the absolute value of
-  ** this memory location.  The sign of meta-value 2 determines the
-  ** synchronous setting.  A negative value means synchronous is off
-  ** and a positive value means synchronous is on.
+  ** Older versions of SQLite would set the default cache size to a
+  ** negative number to indicate synchronous=OFF.  These days, synchronous
+  ** is always on by default regardless of the sign of the default cache
+  ** size.  But continue to take the absolute value of the default cache
+  ** size of historical compatibility.
   */
   if( sqlite3StrICmp(zLeft,"default_cache_size")==0 ){
     static const VdbeOpList getCacheSize[] = {
-      { OP_ReadCookie,  0, 1,        2},  /* 0 */
-      { OP_IfPos,       1, 6,        0},
+      { OP_Transaction, 0, 0,        0},                         /* 0 */
+      { OP_ReadCookie,  0, 1,        BTREE_DEFAULT_CACHE_SIZE},  /* 1 */
+      { OP_IfPos,       1, 7,        0},
       { OP_Integer,     0, 2,        0},
       { OP_Subtract,    1, 2,        1},
-      { OP_IfPos,       1, 6,        0},
-      { OP_Integer,     0, 1,        0},  /* 5 */
+      { OP_IfPos,       1, 7,        0},
+      { OP_Integer,     0, 1,        0},                         /* 6 */
       { OP_ResultRow,   1, 1,        0},
     };
     int addr;
@@ -70467,22 +91483,21 @@ SQLITE_PRIVATE void sqlite3Pragma(
       pParse->nMem += 2;
       addr = sqlite3VdbeAddOpList(v, ArraySize(getCacheSize), getCacheSize);
       sqlite3VdbeChangeP1(v, addr, iDb);
-      sqlite3VdbeChangeP1(v, addr+5, SQLITE_DEFAULT_CACHE_SIZE);
+      sqlite3VdbeChangeP1(v, addr+1, iDb);
+      sqlite3VdbeChangeP1(v, addr+6, SQLITE_DEFAULT_CACHE_SIZE);
     }else{
-      int size = atoi(zRight);
-      if( size<0 ) size = -size;
+      int size = sqlite3AbsInt32(sqlite3Atoi(zRight));
       sqlite3BeginWriteOperation(pParse, 0, iDb);
       sqlite3VdbeAddOp2(v, OP_Integer, size, 1);
-      sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, 2, 2);
-      addr = sqlite3VdbeAddOp2(v, OP_IfPos, 2, 0);
-      sqlite3VdbeAddOp2(v, OP_Integer, -size, 1);
-      sqlite3VdbeJumpHere(v, addr);
-      sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, 2, 1);
+      sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_DEFAULT_CACHE_SIZE, 1);
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
       pDb->pSchema->cache_size = size;
       sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
     }
   }else
+#endif /* !SQLITE_OMIT_PAGER_PRAGMAS && !SQLITE_OMIT_DEPRECATED */
 
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
   /*
   **  PRAGMA [database.]page_size
   **  PRAGMA [database.]page_size=N
@@ -70502,13 +91517,38 @@ SQLITE_PRIVATE void sqlite3Pragma(
       /* Malloc may fail when setting the page-size, as there is an internal
       ** buffer that the pager module resizes using sqlite3_realloc().
       */
-      db->nextPagesize = atoi(zRight);
-      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, -1) ){
+      db->nextPagesize = sqlite3Atoi(zRight);
+      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize,-1,0) ){
         db->mallocFailed = 1;
       }
     }
   }else
 
+  /*
+  **  PRAGMA [database.]secure_delete
+  **  PRAGMA [database.]secure_delete=ON/OFF
+  **
+  ** The first form reports the current setting for the
+  ** secure_delete flag.  The second form changes the secure_delete
+  ** flag setting and reports thenew value.
+  */
+  if( sqlite3StrICmp(zLeft,"secure_delete")==0 ){
+    Btree *pBt = pDb->pBt;
+    int b = -1;
+    assert( pBt!=0 );
+    if( zRight ){
+      b = sqlite3GetBoolean(zRight, 0);
+    }
+    if( pId2->n==0 && b>=0 ){
+      int ii;
+      for(ii=0; ii<db->nDb; ii++){
+        sqlite3BtreeSecureDelete(db->aDb[ii].pBt, b);
+      }
+    }
+    b = sqlite3BtreeSecureDelete(pBt, b);
+    returnSingleInt(pParse, "secure_delete", b);
+  }else
+
   /*
   **  PRAGMA [database.]max_page_count
   **  PRAGMA [database.]max_page_count=N
@@ -70517,34 +91557,31 @@ SQLITE_PRIVATE void sqlite3Pragma(
   ** maximum number of pages in the database file.  The 
   ** second form attempts to change this setting.  Both
   ** forms return the current setting.
-  */
-  if( sqlite3StrICmp(zLeft,"max_page_count")==0 ){
-    Btree *pBt = pDb->pBt;
-    int newMax = 0;
-    assert( pBt!=0 );
-    if( zRight ){
-      newMax = atoi(zRight);
-    }
-    if( ALWAYS(pBt) ){
-      newMax = sqlite3BtreeMaxPageCount(pBt, newMax);
-    }
-    returnSingleInt(pParse, "max_page_count", newMax);
-  }else
-
-  /*
+  **
+  ** The absolute value of N is used.  This is undocumented and might
+  ** change.  The only purpose is to provide an easy way to test
+  ** the sqlite3AbsInt32() function.
+  **
   **  PRAGMA [database.]page_count
   **
   ** Return the number of pages in the specified database.
   */
-  if( sqlite3StrICmp(zLeft,"page_count")==0 ){
+  if( sqlite3StrICmp(zLeft,"page_count")==0
+   || sqlite3StrICmp(zLeft,"max_page_count")==0
+  ){
     int iReg;
     if( sqlite3ReadSchema(pParse) ) goto pragma_out;
     sqlite3CodeVerifySchema(pParse, iDb);
     iReg = ++pParse->nMem;
-    sqlite3VdbeAddOp2(v, OP_Pagecount, iDb, iReg);
+    if( sqlite3Tolower(zLeft[0])=='p' ){
+      sqlite3VdbeAddOp2(v, OP_Pagecount, iDb, iReg);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_MaxPgcnt, iDb, iReg, 
+                        sqlite3AbsInt32(sqlite3Atoi(zRight)));
+    }
     sqlite3VdbeAddOp2(v, OP_ResultRow, iReg, 1);
     sqlite3VdbeSetNumCols(v, 1);
-    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "page_count", SQLITE_STATIC);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zLeft, SQLITE_TRANSIENT);
   }else
 
   /*
@@ -70596,62 +91633,51 @@ SQLITE_PRIVATE void sqlite3Pragma(
 
   /*
   **  PRAGMA [database.]journal_mode
-  **  PRAGMA [database.]journal_mode = (delete|persist|off|truncate|memory)
+  **  PRAGMA [database.]journal_mode =
+  **                      (delete|persist|off|truncate|memory|wal|off)
   */
   if( sqlite3StrICmp(zLeft,"journal_mode")==0 ){
-    int eMode;
-    static char * const azModeName[] = {
-      "delete", "persist", "off", "truncate", "memory"
-    };
+    int eMode;        /* One of the PAGER_JOURNALMODE_XXX symbols */
+    int ii;           /* Loop counter */
 
-    if( zRight==0 ){
-      eMode = PAGER_JOURNALMODE_QUERY;
-    }else{
-      int n = sqlite3Strlen30(zRight);
-      eMode = sizeof(azModeName)/sizeof(azModeName[0]) - 1;
-      while( eMode>=0 && sqlite3StrNICmp(zRight, azModeName[eMode], n)!=0 ){
-        eMode--;
-      }
+    /* Force the schema to be loaded on all databases.  This causes all
+    ** database files to be opened and the journal_modes set.  This is
+    ** necessary because subsequent processing must know if the databases
+    ** are in WAL mode. */
+    if( sqlite3ReadSchema(pParse) ){
+      goto pragma_out;
     }
-    if( pId2->n==0 && eMode==PAGER_JOURNALMODE_QUERY ){
-      /* Simple "PRAGMA journal_mode;" statement. This is a query for
-      ** the current default journal mode (which may be different to
-      ** the journal-mode of the main database).
-      */
-      eMode = db->dfltJournalMode;
-    }else{
-      Pager *pPager;
-      if( pId2->n==0 ){
-        /* This indicates that no database name was specified as part
-        ** of the PRAGMA command. In this case the journal-mode must be
-        ** set on all attached databases, as well as the main db file.
-        **
-        ** Also, the sqlite3.dfltJournalMode variable is set so that
-        ** any subsequently attached databases also use the specified
-        ** journal mode.
-        */
-        int ii;
-        assert(pDb==&db->aDb[0]);
-        for(ii=1; ii<db->nDb; ii++){
-          if( db->aDb[ii].pBt ){
-            pPager = sqlite3BtreePager(db->aDb[ii].pBt);
-            sqlite3PagerJournalMode(pPager, eMode);
-          }
-        }
-        db->dfltJournalMode = (u8)eMode;
-      }
-      pPager = sqlite3BtreePager(pDb->pBt);
-      eMode = sqlite3PagerJournalMode(pPager, eMode);
-    }
-    assert( eMode==PAGER_JOURNALMODE_DELETE
-              || eMode==PAGER_JOURNALMODE_TRUNCATE
-              || eMode==PAGER_JOURNALMODE_PERSIST
-              || eMode==PAGER_JOURNALMODE_OFF
-              || eMode==PAGER_JOURNALMODE_MEMORY );
+
     sqlite3VdbeSetNumCols(v, 1);
     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "journal_mode", SQLITE_STATIC);
-    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, 
-           azModeName[eMode], P4_STATIC);
+
+    if( zRight==0 ){
+      /* If there is no "=MODE" part of the pragma, do a query for the
+      ** current mode */
+      eMode = PAGER_JOURNALMODE_QUERY;
+    }else{
+      const char *zMode;
+      int n = sqlite3Strlen30(zRight);
+      for(eMode=0; (zMode = sqlite3JournalModename(eMode))!=0; eMode++){
+        if( sqlite3StrNICmp(zRight, zMode, n)==0 ) break;
+      }
+      if( !zMode ){
+        /* If the "=MODE" part does not match any known journal mode,
+        ** then do a query */
+        eMode = PAGER_JOURNALMODE_QUERY;
+      }
+    }
+    if( eMode==PAGER_JOURNALMODE_QUERY && pId2->n==0 ){
+      /* Convert "PRAGMA journal_mode" into "PRAGMA main.journal_mode" */
+      iDb = 0;
+      pId2->n = 1;
+    }
+    for(ii=db->nDb-1; ii>=0; ii--){
+      if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
+        sqlite3VdbeUsesBtree(v, ii);
+        sqlite3VdbeAddOp3(v, OP_JournalMode, ii, 1, eMode);
+      }
+    }
     sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
   }else
 
@@ -70665,14 +91691,11 @@ SQLITE_PRIVATE void sqlite3Pragma(
     Pager *pPager = sqlite3BtreePager(pDb->pBt);
     i64 iLimit = -2;
     if( zRight ){
-      int iLimit32 = atoi(zRight);
-      if( iLimit32<-1 ){
-        iLimit32 = -1;
-      }
-      iLimit = iLimit32;
+      sqlite3Atoi64(zRight, &iLimit, 1000000, SQLITE_UTF8);
+      if( iLimit<-1 ) iLimit = -1;
     }
     iLimit = sqlite3PagerJournalSizeLimit(pPager, iLimit);
-    returnSingleInt(pParse, "journal_size_limit", (int)iLimit);
+    returnSingleInt(pParse, "journal_size_limit", iLimit);
   }else
 
 #endif /* SQLITE_OMIT_PAGER_PRAGMAS */
@@ -70709,7 +91732,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
         ** creates the database file. It is important that it is created
         ** as an auto-vacuum capable db.
         */
-        int rc = sqlite3BtreeSetAutoVacuum(pBt, eAuto);
+        rc = sqlite3BtreeSetAutoVacuum(pBt, eAuto);
         if( rc==SQLITE_OK && (eAuto==1 || eAuto==2) ){
           /* When setting the auto_vacuum mode to either "full" or 
           ** "incremental", write the value of meta[6] in the database
@@ -70717,12 +91740,12 @@ SQLITE_PRIVATE void sqlite3Pragma(
           ** that this really is an auto-vacuum capable database.
           */
           static const VdbeOpList setMeta6[] = {
-            { OP_Transaction,    0,               1,        0},    /* 0 */
-            { OP_ReadCookie,     0,               1,        3},    /* 1 */
-            { OP_If,             1,               0,        0},    /* 2 */
-            { OP_Halt,           SQLITE_OK,       OE_Abort, 0},    /* 3 */
-            { OP_Integer,        0,               1,        0},    /* 4 */
-            { OP_SetCookie,      0,               6,        1},    /* 5 */
+            { OP_Transaction,    0,         1,                 0},    /* 0 */
+            { OP_ReadCookie,     0,         1,         BTREE_LARGEST_ROOT_PAGE},
+            { OP_If,             1,         0,                 0},    /* 2 */
+            { OP_Halt,           SQLITE_OK, OE_Abort,          0},    /* 3 */
+            { OP_Integer,        0,         1,                 0},    /* 4 */
+            { OP_SetCookie,      0,         BTREE_INCR_VACUUM, 1},    /* 5 */
           };
           int iAddr;
           iAddr = sqlite3VdbeAddOpList(v, ArraySize(setMeta6), setMeta6);
@@ -70768,22 +91791,19 @@ SQLITE_PRIVATE void sqlite3Pragma(
   **  PRAGMA [database.]cache_size=N
   **
   ** The first form reports the current local setting for the
-  ** page cache size.  The local setting can be different from
-  ** the persistent cache size value that is stored in the database
-  ** file itself.  The value returned is the maximum number of
-  ** pages in the page cache.  The second form sets the local
-  ** page cache size value.  It does not change the persistent
-  ** cache size stored on the disk so the cache size will revert
-  ** to its default value when the database is closed and reopened.
-  ** N should be a positive integer.
+  ** page cache size. The second form sets the local
+  ** page cache size value.  If N is positive then that is the
+  ** number of pages in the cache.  If N is negative, then the
+  ** number of pages is adjusted so that the cache uses -N kibibytes
+  ** of memory.
   */
   if( sqlite3StrICmp(zLeft,"cache_size")==0 ){
     if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
     if( !zRight ){
       returnSingleInt(pParse, "cache_size", pDb->pSchema->cache_size);
     }else{
-      int size = atoi(zRight);
-      if( size<0 ) size = -size;
+      int size = sqlite3Atoi(zRight);
       pDb->pSchema->cache_size = size;
       sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
     }
@@ -70830,7 +91850,6 @@ SQLITE_PRIVATE void sqlite3Pragma(
     }else{
 #ifndef SQLITE_OMIT_WSD
       if( zRight[0] ){
-        int rc;
         int res;
         rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
         if( rc!=SQLITE_OK || res==0 ){
@@ -70846,7 +91865,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
       }
       sqlite3_free(sqlite3_temp_directory);
       if( zRight[0] ){
-        sqlite3_temp_directory = sqlite3DbStrDup(0, zRight);
+        sqlite3_temp_directory = sqlite3_mprintf("%s", zRight);
       }else{
         sqlite3_temp_directory = 0;
       }
@@ -70854,6 +91873,50 @@ SQLITE_PRIVATE void sqlite3Pragma(
     }
   }else
 
+#if SQLITE_OS_WIN
+  /*
+  **   PRAGMA data_store_directory
+  **   PRAGMA data_store_directory = ""|"directory_name"
+  **
+  ** Return or set the local value of the data_store_directory flag.  Changing
+  ** the value sets a specific directory to be used for database files that
+  ** were specified with a relative pathname.  Setting to a null string reverts
+  ** to the default database directory, which for database files specified with
+  ** a relative path will probably be based on the current directory for the
+  ** process.  Database file specified with an absolute path are not impacted
+  ** by this setting, regardless of its value.
+  **
+  */
+  if( sqlite3StrICmp(zLeft, "data_store_directory")==0 ){
+    if( !zRight ){
+      if( sqlite3_data_directory ){
+        sqlite3VdbeSetNumCols(v, 1);
+        sqlite3VdbeSetColName(v, 0, COLNAME_NAME, 
+            "data_store_directory", SQLITE_STATIC);
+        sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, sqlite3_data_directory, 0);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+      }
+    }else{
+#ifndef SQLITE_OMIT_WSD
+      if( zRight[0] ){
+        int res;
+        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
+        if( rc!=SQLITE_OK || res==0 ){
+          sqlite3ErrorMsg(pParse, "not a writable directory");
+          goto pragma_out;
+        }
+      }
+      sqlite3_free(sqlite3_data_directory);
+      if( zRight[0] ){
+        sqlite3_data_directory = sqlite3_mprintf("%s", zRight);
+      }else{
+        sqlite3_data_directory = 0;
+      }
+#endif /* SQLITE_OMIT_WSD */
+    }
+  }else
+#endif
+
 #if !defined(SQLITE_ENABLE_LOCKING_STYLE)
 #  if defined(__APPLE__)
 #    define SQLITE_ENABLE_LOCKING_STYLE 1
@@ -70875,7 +91938,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
       Pager *pPager = sqlite3BtreePager(pDb->pBt);
       char *proxy_file_path = NULL;
       sqlite3_file *pFile = sqlite3PagerFile(pPager);
-      sqlite3OsFileControl(pFile, SQLITE_GET_LOCKPROXYFILE, 
+      sqlite3OsFileControlHint(pFile, SQLITE_GET_LOCKPROXYFILE, 
                            &proxy_file_path);
       
       if( proxy_file_path ){
@@ -70922,7 +91985,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
         sqlite3ErrorMsg(pParse, 
             "Safety level may not be changed inside a transaction");
       }else{
-        pDb->safety_level = getSafetyLevel(zRight)+1;
+        pDb->safety_level = getSafetyLevel(zRight,0,1)+1;
       }
     }
   }else
@@ -70966,7 +92029,6 @@ SQLITE_PRIVATE void sqlite3Pragma(
       sqlite3VdbeSetColName(v, 5, COLNAME_NAME, "pk", SQLITE_STATIC);
       sqlite3ViewGetColumnNames(pParse, pTab);
       for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
-        const Token *pDflt;
         if( IsHiddenColumn(pCol) ){
           nHidden++;
           continue;
@@ -70976,10 +92038,8 @@ SQLITE_PRIVATE void sqlite3Pragma(
         sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
            pCol->zType ? pCol->zType : "", 0);
         sqlite3VdbeAddOp2(v, OP_Integer, (pCol->notNull ? 1 : 0), 4);
-        if( pCol->pDflt ){
-          pDflt = &pCol->pDflt->span;
-          assert( pDflt->z );
-          sqlite3VdbeAddOp4(v, OP_String8, 0, 5, 0, (char*)pDflt->z, pDflt->n);
+        if( pCol->zDflt ){
+          sqlite3VdbeAddOp4(v, OP_String8, 0, 5, 0, (char*)pCol->zDflt, 0);
         }else{
           sqlite3VdbeAddOp2(v, OP_Null, 0, 5);
         }
@@ -71100,8 +92160,8 @@ SQLITE_PRIVATE void sqlite3Pragma(
           int j;
           for(j=0; j<pFK->nCol; j++){
             char *zCol = pFK->aCol[j].zCol;
-            char *zOnUpdate = (char *)actionName(pFK->updateConf);
-            char *zOnDelete = (char *)actionName(pFK->deleteConf);
+            char *zOnDelete = (char *)actionName(pFK->aAction[0]);
+            char *zOnUpdate = (char *)actionName(pFK->aAction[1]);
             sqlite3VdbeAddOp2(v, OP_Integer, i, 1);
             sqlite3VdbeAddOp2(v, OP_Integer, j, 2);
             sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, pFK->zTo, 0);
@@ -71124,7 +92184,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
 #ifndef NDEBUG
   if( sqlite3StrICmp(zLeft, "parser_trace")==0 ){
     if( zRight ){
-      if( getBoolean(zRight) ){
+      if( sqlite3GetBoolean(zRight, 0) ){
         sqlite3ParserTrace(stderr, "parser: ");
       }else{
         sqlite3ParserTrace(0, 0);
@@ -71138,7 +92198,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
   */
   if( sqlite3StrICmp(zLeft, "case_sensitive_like")==0 ){
     if( zRight ){
-      sqlite3RegisterLikeFunctions(db, getBoolean(zRight));
+      sqlite3RegisterLikeFunctions(db, sqlite3GetBoolean(zRight, 0));
     }
   }else
 
@@ -71167,7 +92227,20 @@ SQLITE_PRIVATE void sqlite3Pragma(
       { OP_ResultRow,   3, 1,        0},
     };
 
-    int isQuick = (zLeft[0]=='q');
+    int isQuick = (sqlite3Tolower(zLeft[0])=='q');
+
+    /* If the PRAGMA command was of the form "PRAGMA <db>.integrity_check",
+    ** then iDb is set to the index of the database identified by <db>.
+    ** In this case, the integrity of database iDb only is verified by
+    ** the VDBE created below.
+    **
+    ** Otherwise, if the command was simply "PRAGMA integrity_check" (or
+    ** "PRAGMA quick_check"), then iDb is set to 0. In this case, set iDb
+    ** to -1 here, to indicate that the VDBE should verify the integrity
+    ** of all attached databases.  */
+    assert( iDb>=0 );
+    assert( iDb==0 || pId2->z );
+    if( pId2->z==0 ) iDb = -1;
 
     /* Initialize the VDBE program */
     if( sqlite3ReadSchema(pParse) ) goto pragma_out;
@@ -71178,7 +92251,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
     /* Set the maximum error count */
     mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
     if( zRight ){
-      mxErr = atoi(zRight);
+      sqlite3GetInt32(zRight, &mxErr);
       if( mxErr<=0 ){
         mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
       }
@@ -71192,6 +92265,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
       int cnt = 0;
 
       if( OMIT_TEMPDB && i==1 ) continue;
+      if( iDb>=0 && i!=iDb ) continue;
 
       sqlite3CodeVerifySchema(pParse, i);
       addr = sqlite3VdbeAddOp1(v, OP_IfPos, 1); /* Halt if out of errors */
@@ -71203,6 +92277,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
       ** Begin by filling registers 2, 3, ... with the root pages numbers
       ** for all tables and indices in the database.
       */
+      assert( sqlite3SchemaMutexHeld(db, i, 0) );
       pTbls = &db->aDb[i].pSchema->tblHash;
       for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
         Table *pTab = sqliteHashData(x);
@@ -71214,7 +92289,6 @@ SQLITE_PRIVATE void sqlite3Pragma(
           cnt++;
         }
       }
-      if( cnt==0 ) continue;
 
       /* Make sure sufficient number of registers have been allocated */
       if( pParse->nMem < cnt+4 ){
@@ -71250,6 +92324,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
         sqlite3VdbeAddOp2(v, OP_AddImm, 2, 1);   /* increment entry count */
         for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
           int jmp2;
+          int r1;
           static const VdbeOpList idxErr[] = {
             { OP_AddImm,      1, -1,  0},
             { OP_String8,     0,  3,  0},    /* 1 */
@@ -71263,12 +92338,12 @@ SQLITE_PRIVATE void sqlite3Pragma(
             { OP_IfPos,       1,  0,  0},    /* 9 */
             { OP_Halt,        0,  0,  0},
           };
-          sqlite3GenerateIndexKey(pParse, pIdx, 1, 3, 1);
-          jmp2 = sqlite3VdbeAddOp3(v, OP_Found, j+2, 0, 3);
+          r1 = sqlite3GenerateIndexKey(pParse, pIdx, 1, 3, 0);
+          jmp2 = sqlite3VdbeAddOp4Int(v, OP_Found, j+2, 0, r1, pIdx->nColumn+1);
           addr = sqlite3VdbeAddOpList(v, ArraySize(idxErr), idxErr);
           sqlite3VdbeChangeP4(v, addr+1, "rowid ", P4_STATIC);
           sqlite3VdbeChangeP4(v, addr+3, " missing from index ", P4_STATIC);
-          sqlite3VdbeChangeP4(v, addr+4, pIdx->zName, P4_STATIC);
+          sqlite3VdbeChangeP4(v, addr+4, pIdx->zName, P4_TRANSIENT);
           sqlite3VdbeJumpHere(v, addr+9);
           sqlite3VdbeJumpHere(v, jmp2);
         }
@@ -71287,7 +92362,6 @@ SQLITE_PRIVATE void sqlite3Pragma(
              { OP_Concat,       3,  2,  2},
              { OP_ResultRow,    2,  1,  0},
           };
-          if( pIdx->tnum==0 ) continue;
           addr = sqlite3VdbeAddOp1(v, OP_IfPos, 1);
           sqlite3VdbeAddOp2(v, OP_Halt, 0, 0);
           sqlite3VdbeJumpHere(v, addr);
@@ -71299,7 +92373,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
           sqlite3VdbeJumpHere(v, addr+4);
           sqlite3VdbeChangeP4(v, addr+6, 
                      "wrong # of entries in index ", P4_STATIC);
-          sqlite3VdbeChangeP4(v, addr+7, pIdx->zName, P4_STATIC);
+          sqlite3VdbeChangeP4(v, addr+7, pIdx->zName, P4_TRANSIENT);
         }
       } 
     }
@@ -71413,23 +92487,21 @@ SQLITE_PRIVATE void sqlite3Pragma(
    || sqlite3StrICmp(zLeft, "user_version")==0 
    || sqlite3StrICmp(zLeft, "freelist_count")==0 
   ){
-    int iCookie;   /* Cookie index. 0 for schema-cookie, 6 for user-cookie. */
+    int iCookie;   /* Cookie index. 1 for schema-cookie, 6 for user-cookie. */
     sqlite3VdbeUsesBtree(v, iDb);
     switch( zLeft[0] ){
-      case 's': case 'S':
-        iCookie = 0;
-        break;
       case 'f': case 'F':
-        iCookie = 1;
-        iDb = (-1*(iDb+1));
-        assert(iDb<=0);
+        iCookie = BTREE_FREE_PAGE_COUNT;
+        break;
+      case 's': case 'S':
+        iCookie = BTREE_SCHEMA_VERSION;
         break;
       default:
-        iCookie = 5;
+        iCookie = BTREE_USER_VERSION;
         break;
     }
 
-    if( zRight && iDb>=0 ){
+    if( zRight && iCookie!=BTREE_FREE_PAGE_COUNT ){
       /* Write the specified cookie value */
       static const VdbeOpList setCookie[] = {
         { OP_Transaction,    0,  1,  0},    /* 0 */
@@ -71438,24 +92510,101 @@ SQLITE_PRIVATE void sqlite3Pragma(
       };
       int addr = sqlite3VdbeAddOpList(v, ArraySize(setCookie), setCookie);
       sqlite3VdbeChangeP1(v, addr, iDb);
-      sqlite3VdbeChangeP1(v, addr+1, atoi(zRight));
+      sqlite3VdbeChangeP1(v, addr+1, sqlite3Atoi(zRight));
       sqlite3VdbeChangeP1(v, addr+2, iDb);
       sqlite3VdbeChangeP2(v, addr+2, iCookie);
     }else{
       /* Read the specified cookie value */
       static const VdbeOpList readCookie[] = {
-        { OP_ReadCookie,      0,  1,  0},    /* 0 */
+        { OP_Transaction,     0,  0,  0},    /* 0 */
+        { OP_ReadCookie,      0,  1,  0},    /* 1 */
         { OP_ResultRow,       1,  1,  0}
       };
       int addr = sqlite3VdbeAddOpList(v, ArraySize(readCookie), readCookie);
       sqlite3VdbeChangeP1(v, addr, iDb);
-      sqlite3VdbeChangeP3(v, addr, iCookie);
+      sqlite3VdbeChangeP1(v, addr+1, iDb);
+      sqlite3VdbeChangeP3(v, addr+1, iCookie);
       sqlite3VdbeSetNumCols(v, 1);
       sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zLeft, SQLITE_TRANSIENT);
     }
   }else
 #endif /* SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS */
 
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+  /*
+  **   PRAGMA compile_options
+  **
+  ** Return the names of all compile-time options used in this build,
+  ** one option per row.
+  */
+  if( sqlite3StrICmp(zLeft, "compile_options")==0 ){
+    int i = 0;
+    const char *zOpt;
+    sqlite3VdbeSetNumCols(v, 1);
+    pParse->nMem = 1;
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "compile_option", SQLITE_STATIC);
+    while( (zOpt = sqlite3_compileoption_get(i++))!=0 ){
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, zOpt, 0);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+    }
+  }else
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+#ifndef SQLITE_OMIT_WAL
+  /*
+  **   PRAGMA [database.]wal_checkpoint = passive|full|restart
+  **
+  ** Checkpoint the database.
+  */
+  if( sqlite3StrICmp(zLeft, "wal_checkpoint")==0 ){
+    int iBt = (pId2->z?iDb:SQLITE_MAX_ATTACHED);
+    int eMode = SQLITE_CHECKPOINT_PASSIVE;
+    if( zRight ){
+      if( sqlite3StrICmp(zRight, "full")==0 ){
+        eMode = SQLITE_CHECKPOINT_FULL;
+      }else if( sqlite3StrICmp(zRight, "restart")==0 ){
+        eMode = SQLITE_CHECKPOINT_RESTART;
+      }
+    }
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+    sqlite3VdbeSetNumCols(v, 3);
+    pParse->nMem = 3;
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "busy", SQLITE_STATIC);
+    sqlite3VdbeSetColName(v, 1, COLNAME_NAME, "log", SQLITE_STATIC);
+    sqlite3VdbeSetColName(v, 2, COLNAME_NAME, "checkpointed", SQLITE_STATIC);
+
+    sqlite3VdbeAddOp3(v, OP_Checkpoint, iBt, eMode, 1);
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 3);
+  }else
+
+  /*
+  **   PRAGMA wal_autocheckpoint
+  **   PRAGMA wal_autocheckpoint = N
+  **
+  ** Configure a database connection to automatically checkpoint a database
+  ** after accumulating N frames in the log. Or query for the current value
+  ** of N.
+  */
+  if( sqlite3StrICmp(zLeft, "wal_autocheckpoint")==0 ){
+    if( zRight ){
+      sqlite3_wal_autocheckpoint(db, sqlite3Atoi(zRight));
+    }
+    returnSingleInt(pParse, "wal_autocheckpoint", 
+       db->xWalCallback==sqlite3WalDefaultHook ? 
+           SQLITE_PTR_TO_INT(db->pWalArg) : 0);
+  }else
+#endif
+
+  /*
+  **  PRAGMA shrink_memory
+  **
+  ** This pragma attempts to free as much memory as possible from the
+  ** current database connection.
+  */
+  if( sqlite3StrICmp(zLeft, "shrink_memory")==0 ){
+    sqlite3_db_release_memory(db);
+  }else
+
 #if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
   /*
   ** Report the current state of file logs for all databases
@@ -71490,18 +92639,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
   }else
 #endif
 
-#ifdef SQLITE_SSE
-  /*
-  ** Check to see if the sqlite_statements table exists.  Create it
-  ** if it does not.
-  */
-  if( sqlite3StrICmp(zLeft, "create_sqlite_statement_table")==0 ){
-    extern int sqlite3CreateStatementsTable(Parse*);
-    sqlite3CreateStatementsTable(pParse);
-  }else
-#endif
-
-#if SQLITE_HAS_CODEC
+#ifdef SQLITE_HAS_CODEC
   if( sqlite3StrICmp(zLeft, "key")==0 && zRight ){
     sqlite3_key(db, zRight, sqlite3Strlen30(zRight));
   }else
@@ -71524,17 +92662,15 @@ SQLITE_PRIVATE void sqlite3Pragma(
     }
   }else
 #endif
-#if SQLITE_HAS_CODEC || defined(SQLITE_ENABLE_CEROD)
+#if defined(SQLITE_HAS_CODEC) || defined(SQLITE_ENABLE_CEROD)
   if( sqlite3StrICmp(zLeft, "activate_extensions")==0 ){
-#if SQLITE_HAS_CODEC
+#ifdef SQLITE_HAS_CODEC
     if( sqlite3StrNICmp(zRight, "see-", 4)==0 ){
-      extern void sqlite3_activate_see(const char*);
       sqlite3_activate_see(&zRight[4]);
     }
 #endif
 #ifdef SQLITE_ENABLE_CEROD
     if( sqlite3StrNICmp(zRight, "cerod-", 6)==0 ){
-      extern void sqlite3_activate_cerod(const char*);
       sqlite3_activate_cerod(&zRight[6]);
     }
 #endif
@@ -71544,12 +92680,6 @@ SQLITE_PRIVATE void sqlite3Pragma(
  
   {/* Empty ELSE clause */}
 
-  /* Code an OP_Expire at the end of each PRAGMA program to cause
-  ** the VDBE implementing the pragma to expire. Most (all?) pragmas
-  ** are only valid for a single execution.
-  */
-  sqlite3VdbeAddOp2(v, OP_Expire, 1, 0);
-
   /*
   ** Reset the safety level, in case the fullfsync flag or synchronous
   ** setting changed.
@@ -71557,7 +92687,8 @@ SQLITE_PRIVATE void sqlite3Pragma(
 #ifndef SQLITE_OMIT_PAGER_PRAGMAS
   if( db->autoCommit ){
     sqlite3BtreeSetSafetyLevel(pDb->pBt, pDb->safety_level,
-               (db->flags&SQLITE_FullFSync)!=0);
+               (db->flags&SQLITE_FullFSync)!=0,
+               (db->flags&SQLITE_CkptFullFSync)!=0);
   }
 #endif
 pragma_out:
@@ -71565,7 +92696,7 @@ pragma_out:
   sqlite3DbFree(db, zRight);
 }
 
-#endif /* SQLITE_OMIT_PRAGMA || SQLITE_OMIT_PARSER */
+#endif /* SQLITE_OMIT_PRAGMA */
 
 /************** End of pragma.c **********************************************/
 /************** Begin file prepare.c *****************************************/
@@ -71583,8 +92714,6 @@ pragma_out:
 ** This file contains the implementation of the sqlite3_prepare()
 ** interface, and routines that contribute to loading the database schema
 ** from disk.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 /*
@@ -71599,14 +92728,14 @@ static void corruptSchema(
   sqlite3 *db = pData->db;
   if( !db->mallocFailed && (db->flags & SQLITE_RecoveryMode)==0 ){
     if( zObj==0 ) zObj = "?";
-    sqlite3SetString(pData->pzErrMsg, pData->db,
-       "malformed database schema (%s)", zObj);
-    if( zExtra && zExtra[0] ){
-      *pData->pzErrMsg = sqlite3MAppendf(pData->db, *pData->pzErrMsg, "%s - %s",
-                                  *pData->pzErrMsg, zExtra);
+    sqlite3SetString(pData->pzErrMsg, db,
+      "malformed database schema (%s)", zObj);
+    if( zExtra ){
+      *pData->pzErrMsg = sqlite3MAppendf(db, *pData->pzErrMsg, 
+                                 "%s - %s", *pData->pzErrMsg, zExtra);
     }
   }
-  pData->rc = SQLITE_CORRUPT;
+  pData->rc = db->mallocFailed ? SQLITE_NOMEM : SQLITE_CORRUPT_BKPT;
 }
 
 /*
@@ -71632,7 +92761,7 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
   DbClearProperty(db, iDb, DB_Empty);
   if( db->mallocFailed ){
     corruptSchema(pData, argv[0], 0);
-    return SQLITE_NOMEM;
+    return 1;
   }
 
   assert( iDb>=0 && iDb<db->nDb );
@@ -71645,27 +92774,31 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
     ** or executed.  All the parser does is build the internal data
     ** structures that describe the table, index, or view.
     */
-    char *zErr;
     int rc;
-    u8 lookasideEnabled;
+    sqlite3_stmt *pStmt;
+    TESTONLY(int rcp);            /* Return code from sqlite3_prepare() */
+
     assert( db->init.busy );
     db->init.iDb = iDb;
-    db->init.newTnum = atoi(argv[1]);
-    lookasideEnabled = db->lookaside.bEnabled;
-    db->lookaside.bEnabled = 0;
-    rc = sqlite3_exec(db, argv[2], 0, 0, &zErr);
+    db->init.newTnum = sqlite3Atoi(argv[1]);
+    db->init.orphanTrigger = 0;
+    TESTONLY(rcp = ) sqlite3_prepare(db, argv[2], -1, &pStmt, 0);
+    rc = db->errCode;
+    assert( (rc&0xFF)==(rcp&0xFF) );
     db->init.iDb = 0;
-    db->lookaside.bEnabled = lookasideEnabled;
-    assert( rc!=SQLITE_OK || zErr==0 );
     if( SQLITE_OK!=rc ){
-      pData->rc = rc;
-      if( rc==SQLITE_NOMEM ){
-        db->mallocFailed = 1;
-      }else if( rc!=SQLITE_INTERRUPT ){
-        corruptSchema(pData, argv[0], zErr);
+      if( db->init.orphanTrigger ){
+        assert( iDb==1 );
+      }else{
+        pData->rc = rc;
+        if( rc==SQLITE_NOMEM ){
+          db->mallocFailed = 1;
+        }else if( rc!=SQLITE_INTERRUPT && (rc&0xFF)!=SQLITE_LOCKED ){
+          corruptSchema(pData, argv[0], sqlite3_errmsg(db));
+        }
       }
-      sqlite3DbFree(db, zErr);
     }
+    sqlite3_finalize(pStmt);
   }else if( argv[0]==0 ){
     corruptSchema(pData, 0, 0);
   }else{
@@ -71677,15 +92810,15 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
     */
     Index *pIndex;
     pIndex = sqlite3FindIndex(db, argv[0], db->aDb[iDb].zName);
-    if( pIndex==0 || pIndex->tnum!=0 ){
+    if( pIndex==0 ){
       /* This can occur if there exists an index on a TEMP table which
       ** has the same name as another index on a permanent index.  Since
       ** the permanent table is hidden by the TEMP table, we can also
       ** safely ignore the index on the permanent table.
       */
       /* Do Nothing */;
-    }else{
-      pIndex->tnum = atoi(argv[1]);
+    }else if( sqlite3GetInt32(argv[1], &pIndex->tnum)==0 ){
+      corruptSchema(pData, argv[0], "invalid rootpage");
     }
   }
   return 0;
@@ -71701,15 +92834,16 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
 */
 static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   int rc;
-  BtCursor *curMain;
+  int i;
   int size;
   Table *pTab;
   Db *pDb;
   char const *azArg[4];
-  int meta[10];
+  int meta[5];
   InitData initData;
   char const *zMasterSchema;
-  char const *zMasterName = SCHEMA_TABLE(iDb);
+  char const *zMasterName;
+  int openedTransaction = 0;
 
   /*
   ** The master database table has a structure like this
@@ -71762,15 +92896,13 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   initData.iDb = iDb;
   initData.rc = SQLITE_OK;
   initData.pzErrMsg = pzErrMsg;
-  (void)sqlite3SafetyOff(db);
   sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
-  (void)sqlite3SafetyOn(db);
   if( initData.rc ){
     rc = initData.rc;
     goto error_out;
   }
   pTab = sqlite3FindTable(db, zMasterName, db->aDb[iDb].zName);
-  if( pTab ){
+  if( ALWAYS(pTab) ){
     pTab->tabFlags |= TF_Readonly;
   }
 
@@ -71778,21 +92910,23 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   */
   pDb = &db->aDb[iDb];
   if( pDb->pBt==0 ){
-    if( !OMIT_TEMPDB && iDb==1 ){
+    if( !OMIT_TEMPDB && ALWAYS(iDb==1) ){
       DbSetProperty(db, 1, DB_SchemaLoaded);
     }
     return SQLITE_OK;
   }
-  curMain = sqlite3MallocZero(sqlite3BtreeCursorSize());
-  if( !curMain ){
-    rc = SQLITE_NOMEM;
-    goto error_out;
-  }
+
+  /* If there is not already a read-only (or read-write) transaction opened
+  ** on the b-tree database, open one now. If a transaction is opened, it 
+  ** will be closed before this function returns.  */
   sqlite3BtreeEnter(pDb->pBt);
-  rc = sqlite3BtreeCursor(pDb->pBt, MASTER_ROOT, 0, 0, curMain);
-  if( rc!=SQLITE_OK && rc!=SQLITE_EMPTY ){
-    sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
-    goto initone_error_out;
+  if( !sqlite3BtreeIsInReadTrans(pDb->pBt) ){
+    rc = sqlite3BtreeBeginTrans(pDb->pBt, 0);
+    if( rc!=SQLITE_OK ){
+      sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
+      goto initone_error_out;
+    }
+    openedTransaction = 1;
   }
 
   /* Get the database meta information.
@@ -71801,44 +92935,37 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   **    meta[0]   Schema cookie.  Changes with each schema change.
   **    meta[1]   File format of schema layer.
   **    meta[2]   Size of the page cache.
-  **    meta[3]   Use freelist if 0.  Autovacuum if greater than zero.
+  **    meta[3]   Largest rootpage (auto/incr_vacuum mode)
   **    meta[4]   Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
-  **    meta[5]   The user cookie. Used by the application.
-  **    meta[6]   Incremental-vacuum flag.
-  **    meta[7]
-  **    meta[8]
-  **    meta[9]
+  **    meta[5]   User version
+  **    meta[6]   Incremental vacuum mode
+  **    meta[7]   unused
+  **    meta[8]   unused
+  **    meta[9]   unused
   **
   ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
   ** the possible values of meta[4].
   */
-  if( rc==SQLITE_OK ){
-    int i;
-    for(i=0; i<ArraySize(meta); i++){
-      rc = sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
-      if( rc ){
-        sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
-        goto initone_error_out;
-      }
-    }
-  }else{
-    memset(meta, 0, sizeof(meta));
+  for(i=0; i<ArraySize(meta); i++){
+    sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
   }
-  pDb->pSchema->schema_cookie = meta[0];
+  pDb->pSchema->schema_cookie = meta[BTREE_SCHEMA_VERSION-1];
 
   /* If opening a non-empty database, check the text encoding. For the
   ** main database, set sqlite3.enc to the encoding of the main database.
   ** For an attached db, it is an error if the encoding is not the same
   ** as sqlite3.enc.
   */
-  if( meta[4] ){  /* text encoding */
+  if( meta[BTREE_TEXT_ENCODING-1] ){  /* text encoding */
     if( iDb==0 ){
+      u8 encoding;
       /* If opening the main database, set ENC(db). */
-      ENC(db) = (u8)meta[4];
-      db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
+      encoding = (u8)meta[BTREE_TEXT_ENCODING-1] & 3;
+      if( encoding==0 ) encoding = SQLITE_UTF8;
+      ENC(db) = encoding;
     }else{
       /* If opening an attached database, the encoding much match ENC(db) */
-      if( meta[4]!=ENC(db) ){
+      if( meta[BTREE_TEXT_ENCODING-1]!=ENC(db) ){
         sqlite3SetString(pzErrMsg, db, "attached databases must use the same"
             " text encoding as main database");
         rc = SQLITE_ERROR;
@@ -71851,10 +92978,13 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   pDb->pSchema->enc = ENC(db);
 
   if( pDb->pSchema->cache_size==0 ){
-    size = meta[2];
+#ifndef SQLITE_OMIT_DEPRECATED
+    size = sqlite3AbsInt32(meta[BTREE_DEFAULT_CACHE_SIZE-1]);
     if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
-    if( size<0 ) size = -size;
     pDb->pSchema->cache_size = size;
+#else
+    pDb->pSchema->cache_size = SQLITE_DEFAULT_CACHE_SIZE;
+#endif
     sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
   }
 
@@ -71864,7 +92994,7 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
   ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
   */
-  pDb->pSchema->file_format = (u8)meta[1];
+  pDb->pSchema->file_format = (u8)meta[BTREE_FILE_FORMAT-1];
   if( pDb->pSchema->file_format==0 ){
     pDb->pSchema->file_format = 1;
   }
@@ -71879,22 +93009,18 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   ** not downgrade the database and thus invalidate any descending
   ** indices that the user might have created.
   */
-  if( iDb==0 && meta[1]>=4 ){
+  if( iDb==0 && meta[BTREE_FILE_FORMAT-1]>=4 ){
     db->flags &= ~SQLITE_LegacyFileFmt;
   }
 
   /* Read the schema information out of the schema tables
   */
   assert( db->init.busy );
-  if( rc==SQLITE_EMPTY ){
-    /* For an empty database, there is nothing to read */
-    rc = SQLITE_OK;
-  }else{
+  {
     char *zSql;
     zSql = sqlite3MPrintf(db, 
-        "SELECT name, rootpage, sql FROM '%q'.%s",
+        "SELECT name, rootpage, sql FROM '%q'.%s ORDER BY rowid",
         db->aDb[iDb].zName, zMasterName);
-    (void)sqlite3SafetyOff(db);
 #ifndef SQLITE_OMIT_AUTHORIZATION
     {
       int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
@@ -71907,7 +93033,6 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
     }
 #endif
     if( rc==SQLITE_OK ) rc = initData.rc;
-    (void)sqlite3SafetyOn(db);
     sqlite3DbFree(db, zSql);
 #ifndef SQLITE_OMIT_ANALYZE
     if( rc==SQLITE_OK ){
@@ -71917,14 +93042,14 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   }
   if( db->mallocFailed ){
     rc = SQLITE_NOMEM;
-    sqlite3ResetInternalSchema(db, 0);
+    sqlite3ResetAllSchemasOfConnection(db);
   }
   if( rc==SQLITE_OK || (db->flags&SQLITE_RecoveryMode)){
     /* Black magic: If the SQLITE_RecoveryMode flag is set, then consider
-    ** the schema loaded, even if errors occured. In this situation the 
+    ** the schema loaded, even if errors occurred. In this situation the 
     ** current sqlite3_prepare() operation will fail, but the following one
     ** will attempt to compile the supplied statement against whatever subset
-    ** of the schema was loaded before the error occured. The primary
+    ** of the schema was loaded before the error occurred. The primary
     ** purpose of this is to allow access to the sqlite_master table
     ** even when its contents have been corrupted.
     */
@@ -71937,8 +93062,9 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   ** before that point, jump to error_out.
   */
 initone_error_out:
-  sqlite3BtreeCloseCursor(curMain);
-  sqlite3_free(curMain);
+  if( openedTransaction ){
+    sqlite3BtreeCommit(pDb->pBt);
+  }
   sqlite3BtreeLeave(pDb->pBt);
 
 error_out:
@@ -71963,14 +93089,13 @@ SQLITE_PRIVATE int sqlite3Init(sqlite3 *db, char **pzErrMsg){
   int commit_internal = !(db->flags&SQLITE_InternChanges);
   
   assert( sqlite3_mutex_held(db->mutex) );
-  if( db->init.busy ) return SQLITE_OK;
   rc = SQLITE_OK;
   db->init.busy = 1;
   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
     if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
     rc = sqlite3InitOne(db, i, pzErrMsg);
     if( rc ){
-      sqlite3ResetInternalSchema(db, i);
+      sqlite3ResetOneSchema(db, i);
     }
   }
 
@@ -71979,10 +93104,11 @@ SQLITE_PRIVATE int sqlite3Init(sqlite3 *db, char **pzErrMsg){
   ** schema may contain references to objects in other databases.
   */
 #ifndef SQLITE_OMIT_TEMPDB
-  if( rc==SQLITE_OK && db->nDb>1 && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
+  if( rc==SQLITE_OK && ALWAYS(db->nDb>1)
+                    && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
     rc = sqlite3InitOne(db, 1, pzErrMsg);
     if( rc ){
-      sqlite3ResetInternalSchema(db, 1);
+      sqlite3ResetOneSchema(db, 1);
     }
   }
 #endif
@@ -72016,42 +93142,49 @@ SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse){
 
 /*
 ** Check schema cookies in all databases.  If any cookie is out
-** of date, return 0.  If all schema cookies are current, return 1.
+** of date set pParse->rc to SQLITE_SCHEMA.  If all schema cookies
+** make no changes to pParse->rc.
 */
-static int schemaIsValid(sqlite3 *db){
+static void schemaIsValid(Parse *pParse){
+  sqlite3 *db = pParse->db;
   int iDb;
   int rc;
-  BtCursor *curTemp;
   int cookie;
-  int allOk = 1;
 
-  curTemp = (BtCursor *)sqlite3Malloc(sqlite3BtreeCursorSize());
-  if( curTemp ){
-    assert( sqlite3_mutex_held(db->mutex) );
-    for(iDb=0; allOk && iDb<db->nDb; iDb++){
-      Btree *pBt;
-      pBt = db->aDb[iDb].pBt;
-      if( pBt==0 ) continue;
-      memset(curTemp, 0, sqlite3BtreeCursorSize());
-      rc = sqlite3BtreeCursor(pBt, MASTER_ROOT, 0, 0, curTemp);
-      if( rc==SQLITE_OK ){
-        rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&cookie);
-        if( rc==SQLITE_OK && cookie!=db->aDb[iDb].pSchema->schema_cookie ){
-          allOk = 0;
-        }
-        sqlite3BtreeCloseCursor(curTemp);
-      }
+  assert( pParse->checkSchema );
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(iDb=0; iDb<db->nDb; iDb++){
+    int openedTransaction = 0;         /* True if a transaction is opened */
+    Btree *pBt = db->aDb[iDb].pBt;     /* Btree database to read cookie from */
+    if( pBt==0 ) continue;
+
+    /* If there is not already a read-only (or read-write) transaction opened
+    ** on the b-tree database, open one now. If a transaction is opened, it 
+    ** will be closed immediately after reading the meta-value. */
+    if( !sqlite3BtreeIsInReadTrans(pBt) ){
+      rc = sqlite3BtreeBeginTrans(pBt, 0);
       if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
         db->mallocFailed = 1;
       }
+      if( rc!=SQLITE_OK ) return;
+      openedTransaction = 1;
     }
-    sqlite3_free(curTemp);
-  }else{
-    allOk = 0;
-    db->mallocFailed = 1;
-  }
 
-  return allOk;
+    /* Read the schema cookie from the database. If it does not match the 
+    ** value stored as part of the in-memory schema representation,
+    ** set Parse.rc to SQLITE_SCHEMA. */
+    sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&cookie);
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( cookie!=db->aDb[iDb].pSchema->schema_cookie ){
+      sqlite3ResetOneSchema(db, iDb);
+      pParse->rc = SQLITE_SCHEMA;
+    }
+
+    /* Close the transaction, if one was opened. */
+    if( openedTransaction ){
+      sqlite3BtreeCommit(pBt);
+    }
+  }
 }
 
 /*
@@ -72094,111 +93227,138 @@ static int sqlite3Prepare(
   const char *zSql,         /* UTF-8 encoded SQL statement. */
   int nBytes,               /* Length of zSql in bytes. */
   int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
+  Vdbe *pReprepare,         /* VM being reprepared */
   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
   const char **pzTail       /* OUT: End of parsed string */
 ){
-  Parse sParse;
-  char *zErrMsg = 0;
-  int rc = SQLITE_OK;
-  int i;
+  Parse *pParse;            /* Parsing context */
+  char *zErrMsg = 0;        /* Error message */
+  int rc = SQLITE_OK;       /* Result code */
+  int i;                    /* Loop counter */
 
-  assert( ppStmt );
-  *ppStmt = 0;
-  if( sqlite3SafetyOn(db) ){
-    return SQLITE_MISUSE;
+  /* Allocate the parsing context */
+  pParse = sqlite3StackAllocZero(db, sizeof(*pParse));
+  if( pParse==0 ){
+    rc = SQLITE_NOMEM;
+    goto end_prepare;
   }
+  pParse->pReprepare = pReprepare;
+  assert( ppStmt && *ppStmt==0 );
   assert( !db->mallocFailed );
   assert( sqlite3_mutex_held(db->mutex) );
 
-  /* If any attached database schemas are locked, do not proceed with
-  ** compilation. Instead return SQLITE_LOCKED immediately.
+  /* Check to verify that it is possible to get a read lock on all
+  ** database schemas.  The inability to get a read lock indicates that
+  ** some other database connection is holding a write-lock, which in
+  ** turn means that the other connection has made uncommitted changes
+  ** to the schema.
+  **
+  ** Were we to proceed and prepare the statement against the uncommitted
+  ** schema changes and if those schema changes are subsequently rolled
+  ** back and different changes are made in their place, then when this
+  ** prepared statement goes to run the schema cookie would fail to detect
+  ** the schema change.  Disaster would follow.
+  **
+  ** This thread is currently holding mutexes on all Btrees (because
+  ** of the sqlite3BtreeEnterAll() in sqlite3LockAndPrepare()) so it
+  ** is not possible for another thread to start a new schema change
+  ** while this routine is running.  Hence, we do not need to hold 
+  ** locks on the schema, we just need to make sure nobody else is 
+  ** holding them.
+  **
+  ** Note that setting READ_UNCOMMITTED overrides most lock detection,
+  ** but it does *not* override schema lock detection, so this all still
+  ** works even if READ_UNCOMMITTED is set.
   */
   for(i=0; i<db->nDb; i++) {
     Btree *pBt = db->aDb[i].pBt;
     if( pBt ){
+      assert( sqlite3BtreeHoldsMutex(pBt) );
       rc = sqlite3BtreeSchemaLocked(pBt);
       if( rc ){
         const char *zDb = db->aDb[i].zName;
-        sqlite3Error(db, SQLITE_LOCKED, "database schema is locked: %s", zDb);
-        (void)sqlite3SafetyOff(db);
-        return sqlite3ApiExit(db, SQLITE_LOCKED);
+        sqlite3Error(db, rc, "database schema is locked: %s", zDb);
+        testcase( db->flags & SQLITE_ReadUncommitted );
+        goto end_prepare;
       }
     }
   }
-  
-  memset(&sParse, 0, sizeof(sParse));
-  sParse.db = db;
+
+  sqlite3VtabUnlockList(db);
+
+  pParse->db = db;
+  pParse->nQueryLoop = (double)1;
   if( nBytes>=0 && (nBytes==0 || zSql[nBytes-1]!=0) ){
     char *zSqlCopy;
     int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+    testcase( nBytes==mxLen );
+    testcase( nBytes==mxLen+1 );
     if( nBytes>mxLen ){
       sqlite3Error(db, SQLITE_TOOBIG, "statement too long");
-      (void)sqlite3SafetyOff(db);
-      return sqlite3ApiExit(db, SQLITE_TOOBIG);
+      rc = sqlite3ApiExit(db, SQLITE_TOOBIG);
+      goto end_prepare;
     }
     zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
     if( zSqlCopy ){
-      sqlite3RunParser(&sParse, zSqlCopy, &zErrMsg);
+      sqlite3RunParser(pParse, zSqlCopy, &zErrMsg);
       sqlite3DbFree(db, zSqlCopy);
-      sParse.zTail = &zSql[sParse.zTail-zSqlCopy];
+      pParse->zTail = &zSql[pParse->zTail-zSqlCopy];
     }else{
-      sParse.zTail = &zSql[nBytes];
+      pParse->zTail = &zSql[nBytes];
     }
   }else{
-    sqlite3RunParser(&sParse, zSql, &zErrMsg);
+    sqlite3RunParser(pParse, zSql, &zErrMsg);
   }
+  assert( 1==(int)pParse->nQueryLoop );
 
   if( db->mallocFailed ){
-    sParse.rc = SQLITE_NOMEM;
+    pParse->rc = SQLITE_NOMEM;
   }
-  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
-  if( sParse.checkSchema && !schemaIsValid(db) ){
-    sParse.rc = SQLITE_SCHEMA;
-  }
-  if( sParse.rc==SQLITE_SCHEMA ){
-    sqlite3ResetInternalSchema(db, 0);
+  if( pParse->rc==SQLITE_DONE ) pParse->rc = SQLITE_OK;
+  if( pParse->checkSchema ){
+    schemaIsValid(pParse);
   }
   if( db->mallocFailed ){
-    sParse.rc = SQLITE_NOMEM;
+    pParse->rc = SQLITE_NOMEM;
   }
   if( pzTail ){
-    *pzTail = sParse.zTail;
+    *pzTail = pParse->zTail;
   }
-  rc = sParse.rc;
+  rc = pParse->rc;
 
 #ifndef SQLITE_OMIT_EXPLAIN
-  if( rc==SQLITE_OK && sParse.pVdbe && sParse.explain ){
-    if( sParse.explain==2 ){
-      sqlite3VdbeSetNumCols(sParse.pVdbe, 3);
-      sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "order", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "from", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "detail", SQLITE_STATIC);
+  if( rc==SQLITE_OK && pParse->pVdbe && pParse->explain ){
+    static const char * const azColName[] = {
+       "addr", "opcode", "p1", "p2", "p3", "p4", "p5", "comment",
+       "selectid", "order", "from", "detail"
+    };
+    int iFirst, mx;
+    if( pParse->explain==2 ){
+      sqlite3VdbeSetNumCols(pParse->pVdbe, 4);
+      iFirst = 8;
+      mx = 12;
     }else{
-      sqlite3VdbeSetNumCols(sParse.pVdbe, 8);
-      sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "addr", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "opcode", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "p1", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 3, COLNAME_NAME, "p2", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 4, COLNAME_NAME, "p3", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 5, COLNAME_NAME, "p4", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 6, COLNAME_NAME, "p5", SQLITE_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 7, COLNAME_NAME, "comment", SQLITE_STATIC);
+      sqlite3VdbeSetNumCols(pParse->pVdbe, 8);
+      iFirst = 0;
+      mx = 8;
+    }
+    for(i=iFirst; i<mx; i++){
+      sqlite3VdbeSetColName(pParse->pVdbe, i-iFirst, COLNAME_NAME,
+                            azColName[i], SQLITE_STATIC);
     }
   }
 #endif
 
-  if( sqlite3SafetyOff(db) ){
-    rc = SQLITE_MISUSE;
+  assert( db->init.busy==0 || saveSqlFlag==0 );
+  if( db->init.busy==0 ){
+    Vdbe *pVdbe = pParse->pVdbe;
+    sqlite3VdbeSetSql(pVdbe, zSql, (int)(pParse->zTail-zSql), saveSqlFlag);
   }
-
-  if( saveSqlFlag ){
-    sqlite3VdbeSetSql(sParse.pVdbe, zSql, (int)(sParse.zTail - zSql));
-  }
-  if( rc!=SQLITE_OK || db->mallocFailed ){
-    sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
+  if( pParse->pVdbe && (rc!=SQLITE_OK || db->mallocFailed) ){
+    sqlite3VdbeFinalize(pParse->pVdbe);
     assert(!(*ppStmt));
   }else{
-    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
+    *ppStmt = (sqlite3_stmt*)pParse->pVdbe;
   }
 
   if( zErrMsg ){
@@ -72208,6 +93368,16 @@ static int sqlite3Prepare(
     sqlite3Error(db, rc, 0);
   }
 
+  /* Delete any TriggerPrg structures allocated while parsing this statement. */
+  while( pParse->pTriggerPrg ){
+    TriggerPrg *pT = pParse->pTriggerPrg;
+    pParse->pTriggerPrg = pT->pNext;
+    sqlite3DbFree(db, pT);
+  }
+
+end_prepare:
+
+  sqlite3StackFree(db, pParse);
   rc = sqlite3ApiExit(db, rc);
   assert( (rc&db->errMask)==rc );
   return rc;
@@ -72217,25 +93387,36 @@ static int sqlite3LockAndPrepare(
   const char *zSql,         /* UTF-8 encoded SQL statement. */
   int nBytes,               /* Length of zSql in bytes. */
   int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
+  Vdbe *pOld,               /* VM being reprepared */
   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
   const char **pzTail       /* OUT: End of parsed string */
 ){
   int rc;
+  assert( ppStmt!=0 );
+  *ppStmt = 0;
   if( !sqlite3SafetyCheckOk(db) ){
-    return SQLITE_MISUSE;
+    return SQLITE_MISUSE_BKPT;
   }
   sqlite3_mutex_enter(db->mutex);
   sqlite3BtreeEnterAll(db);
-  rc = sqlite3Prepare(db, zSql, nBytes, saveSqlFlag, ppStmt, pzTail);
+  rc = sqlite3Prepare(db, zSql, nBytes, saveSqlFlag, pOld, ppStmt, pzTail);
+  if( rc==SQLITE_SCHEMA ){
+    sqlite3_finalize(*ppStmt);
+    rc = sqlite3Prepare(db, zSql, nBytes, saveSqlFlag, pOld, ppStmt, pzTail);
+  }
   sqlite3BtreeLeaveAll(db);
   sqlite3_mutex_leave(db->mutex);
+  assert( rc==SQLITE_OK || *ppStmt==0 );
   return rc;
 }
 
 /*
 ** Rerun the compilation of a statement after a schema change.
-** Return true if the statement was recompiled successfully.
-** Return false if there is an error of some kind.
+**
+** If the statement is successfully recompiled, return SQLITE_OK. Otherwise,
+** if the statement cannot be recompiled because another connection has
+** locked the sqlite3_master table, return SQLITE_LOCKED. If any other error
+** occurs, return SQLITE_SCHEMA.
 */
 SQLITE_PRIVATE int sqlite3Reprepare(Vdbe *p){
   int rc;
@@ -72248,13 +93429,13 @@ SQLITE_PRIVATE int sqlite3Reprepare(Vdbe *p){
   assert( zSql!=0 );  /* Reprepare only called for prepare_v2() statements */
   db = sqlite3VdbeDb(p);
   assert( sqlite3_mutex_held(db->mutex) );
-  rc = sqlite3LockAndPrepare(db, zSql, -1, 0, &pNew, 0);
+  rc = sqlite3LockAndPrepare(db, zSql, -1, 0, p, &pNew, 0);
   if( rc ){
     if( rc==SQLITE_NOMEM ){
       db->mallocFailed = 1;
     }
     assert( pNew==0 );
-    return 0;
+    return rc;
   }else{
     assert( pNew!=0 );
   }
@@ -72262,7 +93443,7 @@ SQLITE_PRIVATE int sqlite3Reprepare(Vdbe *p){
   sqlite3TransferBindings(pNew, (sqlite3_stmt*)p);
   sqlite3VdbeResetStepResult((Vdbe*)pNew);
   sqlite3VdbeFinalize((Vdbe*)pNew);
-  return 1;
+  return SQLITE_OK;
 }
 
 
@@ -72282,7 +93463,7 @@ SQLITE_API int sqlite3_prepare(
   const char **pzTail       /* OUT: End of parsed string */
 ){
   int rc;
-  rc = sqlite3LockAndPrepare(db,zSql,nBytes,0,ppStmt,pzTail);
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,0,0,ppStmt,pzTail);
   assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
   return rc;
 }
@@ -72294,7 +93475,7 @@ SQLITE_API int sqlite3_prepare_v2(
   const char **pzTail       /* OUT: End of parsed string */
 ){
   int rc;
-  rc = sqlite3LockAndPrepare(db,zSql,nBytes,1,ppStmt,pzTail);
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,1,0,ppStmt,pzTail);
   assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
   return rc;
 }
@@ -72306,7 +93487,7 @@ SQLITE_API int sqlite3_prepare_v2(
 */
 static int sqlite3Prepare16(
   sqlite3 *db,              /* Database handle. */ 
-  const void *zSql,         /* UTF-8 encoded SQL statement. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
   int nBytes,               /* Length of zSql in bytes. */
   int saveSqlFlag,          /* True to save SQL text into the sqlite3_stmt */
   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
@@ -72320,13 +93501,15 @@ static int sqlite3Prepare16(
   const char *zTail8 = 0;
   int rc = SQLITE_OK;
 
+  assert( ppStmt );
+  *ppStmt = 0;
   if( !sqlite3SafetyCheckOk(db) ){
-    return SQLITE_MISUSE;
+    return SQLITE_MISUSE_BKPT;
   }
   sqlite3_mutex_enter(db->mutex);
-  zSql8 = sqlite3Utf16to8(db, zSql, nBytes);
+  zSql8 = sqlite3Utf16to8(db, zSql, nBytes, SQLITE_UTF16NATIVE);
   if( zSql8 ){
-    rc = sqlite3LockAndPrepare(db, zSql8, -1, saveSqlFlag, ppStmt, &zTail8);
+    rc = sqlite3LockAndPrepare(db, zSql8, -1, saveSqlFlag, 0, ppStmt, &zTail8);
   }
 
   if( zTail8 && pzTail ){
@@ -72354,7 +93537,7 @@ static int sqlite3Prepare16(
 */
 SQLITE_API int sqlite3_prepare16(
   sqlite3 *db,              /* Database handle. */ 
-  const void *zSql,         /* UTF-8 encoded SQL statement. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
   int nBytes,               /* Length of zSql in bytes. */
   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
   const void **pzTail       /* OUT: End of parsed string */
@@ -72366,7 +93549,7 @@ SQLITE_API int sqlite3_prepare16(
 }
 SQLITE_API int sqlite3_prepare16_v2(
   sqlite3 *db,              /* Database handle. */ 
-  const void *zSql,         /* UTF-8 encoded SQL statement. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
   int nBytes,               /* Length of zSql in bytes. */
   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
   const void **pzTail       /* OUT: End of parsed string */
@@ -72394,8 +93577,6 @@ SQLITE_API int sqlite3_prepare16_v2(
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** to handle SELECT statements in SQLite.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 
@@ -72420,10 +93601,10 @@ static void clearSelect(sqlite3 *db, Select *p){
 */
 SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
   pDest->eDest = (u8)eDest;
-  pDest->iParm = iParm;
-  pDest->affinity = 0;
-  pDest->iMem = 0;
-  pDest->nMem = 0;
+  pDest->iSDParm = iParm;
+  pDest->affSdst = 0;
+  pDest->iSdst = 0;
+  pDest->nSdst = 0;
 }
 
 
@@ -72449,13 +93630,15 @@ SQLITE_PRIVATE Select *sqlite3SelectNew(
   pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
   assert( db->mallocFailed || !pOffset || pLimit ); /* OFFSET implies LIMIT */
   if( pNew==0 ){
+    assert( db->mallocFailed );
     pNew = &standin;
     memset(pNew, 0, sizeof(*pNew));
   }
   if( pEList==0 ){
-    pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0,0,0), 0);
+    pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0));
   }
   pNew->pEList = pEList;
+  if( pSrc==0 ) pSrc = sqlite3DbMallocZero(db, sizeof(*pSrc));
   pNew->pSrc = pSrc;
   pNew->pWhere = pWhere;
   pNew->pGroupBy = pGroupBy;
@@ -72465,6 +93648,7 @@ SQLITE_PRIVATE Select *sqlite3SelectNew(
   pNew->op = TK_SELECT;
   pNew->pLimit = pLimit;
   pNew->pOffset = pOffset;
+  assert( pOffset==0 || pLimit!=0 );
   pNew->addrOpenEphm[0] = -1;
   pNew->addrOpenEphm[1] = -1;
   pNew->addrOpenEphm[2] = -1;
@@ -72472,7 +93656,10 @@ SQLITE_PRIVATE Select *sqlite3SelectNew(
     clearSelect(db, pNew);
     if( pNew!=&standin ) sqlite3DbFree(db, pNew);
     pNew = 0;
+  }else{
+    assert( pNew->pSrc!=0 || pParse->nErr>0 );
   }
+  assert( pNew!=&standin );
   return pNew;
 }
 
@@ -72507,18 +93694,20 @@ SQLITE_PRIVATE int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *p
   int jointype = 0;
   Token *apAll[3];
   Token *p;
+                             /*   0123456789 123456789 123456789 123 */
+  static const char zKeyText[] = "naturaleftouterightfullinnercross";
   static const struct {
-    const char zKeyword[8];
-    u8 nChar;
-    u8 code;
-  } keywords[] = {
-    { "natural", 7, JT_NATURAL },
-    { "left",    4, JT_LEFT|JT_OUTER },
-    { "right",   5, JT_RIGHT|JT_OUTER },
-    { "full",    4, JT_LEFT|JT_RIGHT|JT_OUTER },
-    { "outer",   5, JT_OUTER },
-    { "inner",   5, JT_INNER },
-    { "cross",   5, JT_INNER|JT_CROSS },
+    u8 i;        /* Beginning of keyword text in zKeyText[] */
+    u8 nChar;    /* Length of the keyword in characters */
+    u8 code;     /* Join type mask */
+  } aKeyword[] = {
+    /* natural */ { 0,  7, JT_NATURAL                },
+    /* left    */ { 6,  4, JT_LEFT|JT_OUTER          },
+    /* outer   */ { 10, 5, JT_OUTER                  },
+    /* right   */ { 14, 5, JT_RIGHT|JT_OUTER         },
+    /* full    */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
+    /* inner   */ { 23, 5, JT_INNER                  },
+    /* cross   */ { 28, 5, JT_INNER|JT_CROSS         },
   };
   int i, j;
   apAll[0] = pA;
@@ -72526,14 +93715,15 @@ SQLITE_PRIVATE int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *p
   apAll[2] = pC;
   for(i=0; i<3 && apAll[i]; i++){
     p = apAll[i];
-    for(j=0; j<ArraySize(keywords); j++){
-      if( p->n==keywords[j].nChar 
-          && sqlite3StrNICmp((char*)p->z, keywords[j].zKeyword, p->n)==0 ){
-        jointype |= keywords[j].code;
+    for(j=0; j<ArraySize(aKeyword); j++){
+      if( p->n==aKeyword[j].nChar 
+          && sqlite3StrNICmp((char*)p->z, &zKeyText[aKeyword[j].i], p->n)==0 ){
+        jointype |= aKeyword[j].code;
         break;
       }
     }
-    if( j>=ArraySize(keywords) ){
+    testcase( j==0 || j==1 || j==2 || j==3 || j==4 || j==5 || j==6 );
+    if( j>=ArraySize(aKeyword) ){
       jointype |= JT_ERROR;
       break;
     }
@@ -72548,7 +93738,8 @@ SQLITE_PRIVATE int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *p
     sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
        "%T %T%s%T", pA, pB, zSp, pC);
     jointype = JT_INNER;
-  }else if( jointype & JT_RIGHT ){
+  }else if( (jointype & JT_OUTER)!=0 
+         && (jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ){
     sqlite3ErrorMsg(pParse, 
       "RIGHT and FULL OUTER JOINs are not currently supported");
     jointype = JT_INNER;
@@ -72569,96 +93760,80 @@ static int columnIndex(Table *pTab, const char *zCol){
 }
 
 /*
-** Set the value of a token to a '\000'-terminated string.
-*/
-static void setToken(Token *p, const char *z){
-  p->z = (u8*)z;
-  p->n = z ? sqlite3Strlen30(z) : 0;
-  p->dyn = 0;
-}
-
-/*
-** Set the token to the double-quoted and escaped version of the string pointed
-** to by z. For example;
+** Search the first N tables in pSrc, from left to right, looking for a
+** table that has a column named zCol.  
 **
-**    {a"bc}  ->  {"a""bc"}
+** When found, set *piTab and *piCol to the table index and column index
+** of the matching column and return TRUE.
+**
+** If not found, return FALSE.
 */
-static void setQuotedToken(Parse *pParse, Token *p, const char *z){
+static int tableAndColumnIndex(
+  SrcList *pSrc,       /* Array of tables to search */
+  int N,               /* Number of tables in pSrc->a[] to search */
+  const char *zCol,    /* Name of the column we are looking for */
+  int *piTab,          /* Write index of pSrc->a[] here */
+  int *piCol           /* Write index of pSrc->a[*piTab].pTab->aCol[] here */
+){
+  int i;               /* For looping over tables in pSrc */
+  int iCol;            /* Index of column matching zCol */
 
-  /* Check if the string appears to be quoted using "..." or `...`
-  ** or [...] or '...' or if the string contains any " characters.  
-  ** If it does, then record a version of the string with the special
-  ** characters escaped.
-  */
-  const char *z2 = z;
-  if( *z2!='[' && *z2!='`' && *z2!='\'' ){
-    while( *z2 ){
-      if( *z2=='"' ) break;
-      z2++;
+  assert( (piTab==0)==(piCol==0) );  /* Both or neither are NULL */
+  for(i=0; i<N; i++){
+    iCol = columnIndex(pSrc->a[i].pTab, zCol);
+    if( iCol>=0 ){
+      if( piTab ){
+        *piTab = i;
+        *piCol = iCol;
+      }
+      return 1;
     }
   }
-
-  if( *z2 ){
-    /* String contains " characters - copy and quote the string. */
-    p->z = (u8 *)sqlite3MPrintf(pParse->db, "\"%w\"", z);
-    if( p->z ){
-      p->n = sqlite3Strlen30((char *)p->z);
-      p->dyn = 1;
-    }
-  }else{
-    /* String contains no " characters - copy the pointer. */
-    p->z = (u8*)z;
-    p->n = (int)(z2 - z);
-    p->dyn = 0;
-  }
+  return 0;
 }
 
 /*
-** Create an expression node for an identifier with the name of zName
-*/
-SQLITE_PRIVATE Expr *sqlite3CreateIdExpr(Parse *pParse, const char *zName){
-  Token dummy;
-  setToken(&dummy, zName);
-  return sqlite3PExpr(pParse, TK_ID, 0, 0, &dummy);
-}
-
-/*
-** Add a term to the WHERE expression in *ppExpr that requires the
-** zCol column to be equal in the two tables pTab1 and pTab2.
+** This function is used to add terms implied by JOIN syntax to the
+** WHERE clause expression of a SELECT statement. The new term, which
+** is ANDed with the existing WHERE clause, is of the form:
+**
+**    (tab1.col1 = tab2.col2)
+**
+** where tab1 is the iSrc'th table in SrcList pSrc and tab2 is the 
+** (iSrc+1)'th. Column col1 is column iColLeft of tab1, and col2 is
+** column iColRight of tab2.
 */
 static void addWhereTerm(
-  Parse *pParse,           /* Parsing context */
-  const char *zCol,        /* Name of the column */
-  const Table *pTab1,      /* First table */
-  const char *zAlias1,     /* Alias for first table.  May be NULL */
-  const Table *pTab2,      /* Second table */
-  const char *zAlias2,     /* Alias for second table.  May be NULL */
-  int iRightJoinTable,     /* VDBE cursor for the right table */
-  Expr **ppExpr,           /* Add the equality term to this expression */
-  int isOuterJoin          /* True if dealing with an OUTER join */
+  Parse *pParse,                  /* Parsing context */
+  SrcList *pSrc,                  /* List of tables in FROM clause */
+  int iLeft,                      /* Index of first table to join in pSrc */
+  int iColLeft,                   /* Index of column in first table */
+  int iRight,                     /* Index of second table in pSrc */
+  int iColRight,                  /* Index of column in second table */
+  int isOuterJoin,                /* True if this is an OUTER join */
+  Expr **ppWhere                  /* IN/OUT: The WHERE clause to add to */
 ){
-  Expr *pE1a, *pE1b, *pE1c;
-  Expr *pE2a, *pE2b, *pE2c;
-  Expr *pE;
+  sqlite3 *db = pParse->db;
+  Expr *pE1;
+  Expr *pE2;
+  Expr *pEq;
 
-  pE1a = sqlite3CreateIdExpr(pParse, zCol);
-  pE2a = sqlite3CreateIdExpr(pParse, zCol);
-  if( zAlias1==0 ){
-    zAlias1 = pTab1->zName;
+  assert( iLeft<iRight );
+  assert( pSrc->nSrc>iRight );
+  assert( pSrc->a[iLeft].pTab );
+  assert( pSrc->a[iRight].pTab );
+
+  pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iColLeft);
+  pE2 = sqlite3CreateColumnExpr(db, pSrc, iRight, iColRight);
+
+  pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2, 0);
+  if( pEq && isOuterJoin ){
+    ExprSetProperty(pEq, EP_FromJoin);
+    assert( !ExprHasAnyProperty(pEq, EP_TokenOnly|EP_Reduced) );
+    ExprSetIrreducible(pEq);
+    pEq->iRightJoinTable = (i16)pE2->iTable;
   }
-  pE1b = sqlite3CreateIdExpr(pParse, zAlias1);
-  if( zAlias2==0 ){
-    zAlias2 = pTab2->zName;
-  }
-  pE2b = sqlite3CreateIdExpr(pParse, zAlias2);
-  pE1c = sqlite3PExpr(pParse, TK_DOT, pE1b, pE1a, 0);
-  pE2c = sqlite3PExpr(pParse, TK_DOT, pE2b, pE2a, 0);
-  pE = sqlite3PExpr(pParse, TK_EQ, pE1c, pE2c, 0);
-  if( pE && isOuterJoin ){
-    ExprSetProperty(pE, EP_FromJoin);
-    pE->iRightJoinTable = iRightJoinTable;
-  }
-  *ppExpr = sqlite3ExprAnd(pParse->db,*ppExpr, pE);
+  *ppWhere = sqlite3ExprAnd(db, *ppWhere, pEq);
 }
 
 /*
@@ -72690,7 +93865,9 @@ static void addWhereTerm(
 static void setJoinExpr(Expr *p, int iTable){
   while( p ){
     ExprSetProperty(p, EP_FromJoin);
-    p->iRightJoinTable = iTable;
+    assert( !ExprHasAnyProperty(p, EP_TokenOnly|EP_Reduced) );
+    ExprSetIrreducible(p);
+    p->iRightJoinTable = (i16)iTable;
     setJoinExpr(p->pLeft, iTable);
     p = p->pRight;
   } 
@@ -72736,13 +93913,15 @@ static int sqliteProcessJoin(Parse *pParse, Select *p){
            "an ON or USING clause", 0);
         return 1;
       }
-      for(j=0; j<pLeftTab->nCol; j++){
-        char *zName = pLeftTab->aCol[j].zName;
-        if( columnIndex(pRightTab, zName)>=0 ){
-          addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias, 
-                              pRightTab, pRight->zAlias,
-                              pRight->iCursor, &p->pWhere, isOuter);
-          
+      for(j=0; j<pRightTab->nCol; j++){
+        char *zName;   /* Name of column in the right table */
+        int iLeft;     /* Matching left table */
+        int iLeftCol;  /* Matching column in the left table */
+
+        zName = pRightTab->aCol[j].zName;
+        if( tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol) ){
+          addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, j,
+                       isOuter, &p->pWhere);
         }
       }
     }
@@ -72774,15 +93953,22 @@ static int sqliteProcessJoin(Parse *pParse, Select *p){
     if( pRight->pUsing ){
       IdList *pList = pRight->pUsing;
       for(j=0; j<pList->nId; j++){
-        char *zName = pList->a[j].zName;
-        if( columnIndex(pLeftTab, zName)<0 || columnIndex(pRightTab, zName)<0 ){
+        char *zName;     /* Name of the term in the USING clause */
+        int iLeft;       /* Table on the left with matching column name */
+        int iLeftCol;    /* Column number of matching column on the left */
+        int iRightCol;   /* Column number of matching column on the right */
+
+        zName = pList->a[j].zName;
+        iRightCol = columnIndex(pRightTab, zName);
+        if( iRightCol<0
+         || !tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol)
+        ){
           sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
             "not present in both tables", zName);
           return 1;
         }
-        addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias, 
-                            pRightTab, pRight->zAlias,
-                            pRight->iCursor, &p->pWhere, isOuter);
+        addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, iRightCol,
+                     isOuter, &p->pWhere);
       }
     }
   }
@@ -72803,11 +93989,18 @@ static void pushOntoSorter(
   int nExpr = pOrderBy->nExpr;
   int regBase = sqlite3GetTempRange(pParse, nExpr+2);
   int regRecord = sqlite3GetTempReg(pParse);
+  int op;
+  sqlite3ExprCacheClear(pParse);
   sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
   sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
   sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
   sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
-  sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
+  if( pSelect->selFlags & SF_UseSorter ){
+    op = OP_SorterInsert;
+  }else{
+    op = OP_IdxInsert;
+  }
+  sqlite3VdbeAddOp2(v, op, pOrderBy->iECursor, regRecord);
   sqlite3ReleaseTempReg(pParse, regRecord);
   sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
   if( pSelect->iLimit ){
@@ -72825,7 +94018,6 @@ static void pushOntoSorter(
     sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
     sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
     sqlite3VdbeJumpHere(v, addr2);
-    pSelect->iLimit = 0;
   }
 }
 
@@ -72868,17 +94060,19 @@ static void codeDistinct(
 
   v = pParse->pVdbe;
   r1 = sqlite3GetTempReg(pParse);
+  sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, iMem, N);
   sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
-  sqlite3VdbeAddOp3(v, OP_Found, iTab, addrRepeat, r1);
   sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
   sqlite3ReleaseTempReg(pParse, r1);
 }
 
+#ifndef SQLITE_OMIT_SUBQUERY
 /*
 ** Generate an error message when a SELECT is used within a subexpression
 ** (example:  "a IN (SELECT * FROM table)") but it has more than 1 result
-** column.  We do this in a subroutine because the error occurs in multiple
-** places.
+** column.  We do this in a subroutine because the error used to occur
+** in multiple places.  (The error only occurs in one place now, but we
+** retain the subroutine to minimize code disruption.)
 */
 static int checkForMultiColumnSelectError(
   Parse *pParse,       /* Parse context. */
@@ -72894,6 +94088,7 @@ static int checkForMultiColumnSelectError(
     return 0;
   }
 }
+#endif
 
 /*
 ** This routine generates the code for the inside of the inner loop
@@ -72921,7 +94116,7 @@ static void selectInnerLoop(
   int hasDistinct;        /* True if the DISTINCT keyword is present */
   int regResult;              /* Start of memory holding result set */
   int eDest = pDest->eDest;   /* How to dispose of results */
-  int iParm = pDest->iParm;   /* First argument to disposal method */
+  int iParm = pDest->iSDParm; /* First argument to disposal method */
   int nResultCol;             /* Number of result columns */
 
   assert( v );
@@ -72939,14 +94134,14 @@ static void selectInnerLoop(
   }else{
     nResultCol = pEList->nExpr;
   }
-  if( pDest->iMem==0 ){
-    pDest->iMem = pParse->nMem+1;
-    pDest->nMem = nResultCol;
+  if( pDest->iSdst==0 ){
+    pDest->iSdst = pParse->nMem+1;
+    pDest->nSdst = nResultCol;
     pParse->nMem += nResultCol;
   }else{ 
-    assert( pDest->nMem==nResultCol );
+    assert( pDest->nSdst==nResultCol );
   }
-  regResult = pDest->iMem;
+  regResult = pDest->iSdst;
   if( nColumn>0 ){
     for(i=0; i<nColumn; i++){
       sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
@@ -72955,6 +94150,7 @@ static void selectInnerLoop(
     /* If the destination is an EXISTS(...) expression, the actual
     ** values returned by the SELECT are not required.
     */
+    sqlite3ExprCacheClear(pParse);
     sqlite3ExprCodeExprList(pParse, pEList, regResult, eDest==SRT_Output);
   }
   nColumn = nResultCol;
@@ -72972,10 +94168,6 @@ static void selectInnerLoop(
     }
   }
 
-  if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
-    return;
-  }
-
   switch( eDest ){
     /* In this mode, write each query result to the key of the temporary
     ** table iParm.
@@ -73005,6 +94197,8 @@ static void selectInnerLoop(
     case SRT_Table:
     case SRT_EphemTab: {
       int r1 = sqlite3GetTempReg(pParse);
+      testcase( eDest==SRT_Table );
+      testcase( eDest==SRT_EphemTab );
       sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
       if( pOrderBy ){
         pushOntoSorter(pParse, pOrderBy, p, r1);
@@ -73026,7 +94220,7 @@ static void selectInnerLoop(
     */
     case SRT_Set: {
       assert( nColumn==1 );
-      p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affinity);
+      p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affSdst);
       if( pOrderBy ){
         /* At first glance you would think we could optimize out the
         ** ORDER BY in this case since the order of entries in the set
@@ -73073,13 +94267,15 @@ static void selectInnerLoop(
     */
     case SRT_Coroutine:
     case SRT_Output: {
+      testcase( eDest==SRT_Coroutine );
+      testcase( eDest==SRT_Output );
       if( pOrderBy ){
         int r1 = sqlite3GetTempReg(pParse);
         sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
         pushOntoSorter(pParse, pOrderBy, p, r1);
         sqlite3ReleaseTempReg(pParse, r1);
       }else if( eDest==SRT_Coroutine ){
-        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
+        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
       }else{
         sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
         sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
@@ -73100,13 +94296,12 @@ static void selectInnerLoop(
 #endif
   }
 
-  /* Jump to the end of the loop if the LIMIT is reached.
+  /* Jump to the end of the loop if the LIMIT is reached.  Except, if
+  ** there is a sorter, in which case the sorter has already limited
+  ** the output for us.
   */
-  if( p->iLimit ){
-    assert( pOrderBy==0 );  /* If there is an ORDER BY, the call to
-                            ** pushOntoSorter() would have cleared p->iLimit */
-    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
-    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
+  if( pOrderBy==0 && p->iLimit ){
+    sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
   }
 }
 
@@ -73152,6 +94347,92 @@ static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
   return pInfo;
 }
 
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Name of the connection operator, used for error messages.
+*/
+static const char *selectOpName(int id){
+  char *z;
+  switch( id ){
+    case TK_ALL:       z = "UNION ALL";   break;
+    case TK_INTERSECT: z = "INTERSECT";   break;
+    case TK_EXCEPT:    z = "EXCEPT";      break;
+    default:           z = "UNION";       break;
+  }
+  return z;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
+** is a no-op. Otherwise, it adds a single row of output to the EQP result,
+** where the caption is of the form:
+**
+**   "USE TEMP B-TREE FOR xxx"
+**
+** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
+** is determined by the zUsage argument.
+*/
+static void explainTempTable(Parse *pParse, const char *zUsage){
+  if( pParse->explain==2 ){
+    Vdbe *v = pParse->pVdbe;
+    char *zMsg = sqlite3MPrintf(pParse->db, "USE TEMP B-TREE FOR %s", zUsage);
+    sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
+  }
+}
+
+/*
+** Assign expression b to lvalue a. A second, no-op, version of this macro
+** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
+** in sqlite3Select() to assign values to structure member variables that
+** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
+** code with #ifndef directives.
+*/
+# define explainSetInteger(a, b) a = b
+
+#else
+/* No-op versions of the explainXXX() functions and macros. */
+# define explainTempTable(y,z)
+# define explainSetInteger(y,z)
+#endif
+
+#if !defined(SQLITE_OMIT_EXPLAIN) && !defined(SQLITE_OMIT_COMPOUND_SELECT)
+/*
+** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
+** is a no-op. Otherwise, it adds a single row of output to the EQP result,
+** where the caption is of one of the two forms:
+**
+**   "COMPOSITE SUBQUERIES iSub1 and iSub2 (op)"
+**   "COMPOSITE SUBQUERIES iSub1 and iSub2 USING TEMP B-TREE (op)"
+**
+** where iSub1 and iSub2 are the integers passed as the corresponding
+** function parameters, and op is the text representation of the parameter
+** of the same name. The parameter "op" must be one of TK_UNION, TK_EXCEPT,
+** TK_INTERSECT or TK_ALL. The first form is used if argument bUseTmp is 
+** false, or the second form if it is true.
+*/
+static void explainComposite(
+  Parse *pParse,                  /* Parse context */
+  int op,                         /* One of TK_UNION, TK_EXCEPT etc. */
+  int iSub1,                      /* Subquery id 1 */
+  int iSub2,                      /* Subquery id 2 */
+  int bUseTmp                     /* True if a temp table was used */
+){
+  assert( op==TK_UNION || op==TK_EXCEPT || op==TK_INTERSECT || op==TK_ALL );
+  if( pParse->explain==2 ){
+    Vdbe *v = pParse->pVdbe;
+    char *zMsg = sqlite3MPrintf(
+        pParse->db, "COMPOUND SUBQUERIES %d AND %d %s(%s)", iSub1, iSub2,
+        bUseTmp?"USING TEMP B-TREE ":"", selectOpName(op)
+    );
+    sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
+  }
+}
+#else
+/* No-op versions of the explainXXX() functions and macros. */
+# define explainComposite(v,w,x,y,z)
+#endif
 
 /*
 ** If the inner loop was generated using a non-null pOrderBy argument,
@@ -73174,22 +94455,34 @@ static void generateSortTail(
   ExprList *pOrderBy = p->pOrderBy;
 
   int eDest = pDest->eDest;
-  int iParm = pDest->iParm;
+  int iParm = pDest->iSDParm;
 
   int regRow;
   int regRowid;
 
   iTab = pOrderBy->iECursor;
+  regRow = sqlite3GetTempReg(pParse);
   if( eDest==SRT_Output || eDest==SRT_Coroutine ){
     pseudoTab = pParse->nTab++;
-    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, nColumn);
-    sqlite3VdbeAddOp2(v, OP_OpenPseudo, pseudoTab, eDest==SRT_Output);
+    sqlite3VdbeAddOp3(v, OP_OpenPseudo, pseudoTab, regRow, nColumn);
+    regRowid = 0;
+  }else{
+    regRowid = sqlite3GetTempReg(pParse);
+  }
+  if( p->selFlags & SF_UseSorter ){
+    int regSortOut = ++pParse->nMem;
+    int ptab2 = pParse->nTab++;
+    sqlite3VdbeAddOp3(v, OP_OpenPseudo, ptab2, regSortOut, pOrderBy->nExpr+2);
+    addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
+    codeOffset(v, p, addrContinue);
+    sqlite3VdbeAddOp2(v, OP_SorterData, iTab, regSortOut);
+    sqlite3VdbeAddOp3(v, OP_Column, ptab2, pOrderBy->nExpr+1, regRow);
+    sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
+  }else{
+    addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak);
+    codeOffset(v, p, addrContinue);
+    sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr+1, regRow);
   }
-  addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak);
-  codeOffset(v, p, addrContinue);
-  regRow = sqlite3GetTempReg(pParse);
-  regRowid = sqlite3GetTempReg(pParse);
-  sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr + 1, regRow);
   switch( eDest ){
     case SRT_Table:
     case SRT_EphemTab: {
@@ -73215,41 +94508,38 @@ static void generateSortTail(
       break;
     }
 #endif
-    case SRT_Output:
-    case SRT_Coroutine: {
+    default: {
       int i;
+      assert( eDest==SRT_Output || eDest==SRT_Coroutine ); 
       testcase( eDest==SRT_Output );
       testcase( eDest==SRT_Coroutine );
-      sqlite3VdbeAddOp2(v, OP_Integer, 1, regRowid);
-      sqlite3VdbeAddOp3(v, OP_Insert, pseudoTab, regRow, regRowid);
       for(i=0; i<nColumn; i++){
-        assert( regRow!=pDest->iMem+i );
-        sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
+        assert( regRow!=pDest->iSdst+i );
+        sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iSdst+i);
+        if( i==0 ){
+          sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
+        }
       }
       if( eDest==SRT_Output ){
-        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
-        sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iSdst, nColumn);
+        sqlite3ExprCacheAffinityChange(pParse, pDest->iSdst, nColumn);
       }else{
-        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
+        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
       }
       break;
     }
-    default: {
-      /* Do nothing */
-      break;
-    }
   }
   sqlite3ReleaseTempReg(pParse, regRow);
   sqlite3ReleaseTempReg(pParse, regRowid);
 
-  /* LIMIT has been implemented by the pushOntoSorter() routine.
-  */
-  assert( p->iLimit==0 );
-
   /* The bottom of the loop
   */
   sqlite3VdbeResolveLabel(v, addrContinue);
-  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
+  if( p->selFlags & SF_UseSorter ){
+    sqlite3VdbeAddOp2(v, OP_SorterNext, iTab, addr);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
+  }
   sqlite3VdbeResolveLabel(v, addrBreak);
   if( eDest==SRT_Output || eDest==SRT_Coroutine ){
     sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
@@ -73286,7 +94576,7 @@ static const char *columnType(
   char const *zOriginTab = 0;
   char const *zOriginCol = 0;
   int j;
-  if( pExpr==0 || pNC->pSrcList==0 ) return 0;
+  if( NEVER(pExpr==0) || pNC->pSrcList==0 ) return 0;
 
   switch( pExpr->op ){
     case TK_AGG_COLUMN:
@@ -73298,6 +94588,8 @@ static const char *columnType(
       Table *pTab = 0;            /* Table structure column is extracted from */
       Select *pS = 0;             /* Select the column is extracted from */
       int iCol = pExpr->iColumn;  /* Index of column in pTab */
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      testcase( pExpr->op==TK_COLUMN );
       while( pNC && !pTab ){
         SrcList *pTabList = pNC->pSrcList;
         for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
@@ -73310,27 +94602,33 @@ static const char *columnType(
       }
 
       if( pTab==0 ){
-        /* FIX ME:
-        ** This can occurs if you have something like "SELECT new.x;" inside
-        ** a trigger.  In other words, if you reference the special "new"
-        ** table in the result set of a select.  We do not have a good way
-        ** to find the actual table type, so call it "TEXT".  This is really
-        ** something of a bug, but I do not know how to fix it.
+        /* At one time, code such as "SELECT new.x" within a trigger would
+        ** cause this condition to run.  Since then, we have restructured how
+        ** trigger code is generated and so this condition is no longer 
+        ** possible. However, it can still be true for statements like
+        ** the following:
         **
-        ** This code does not produce the correct answer - it just prevents
-        ** a segfault.  See ticket #1229.
-        */
-        zType = "TEXT";
+        **   CREATE TABLE t1(col INTEGER);
+        **   SELECT (SELECT t1.col) FROM FROM t1;
+        **
+        ** when columnType() is called on the expression "t1.col" in the 
+        ** sub-select. In this case, set the column type to NULL, even
+        ** though it should really be "INTEGER".
+        **
+        ** This is not a problem, as the column type of "t1.col" is never
+        ** used. When columnType() is called on the expression 
+        ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT
+        ** branch below.  */
         break;
       }
 
-      assert( pTab );
+      assert( pTab && pExpr->pTab==pTab );
       if( pS ){
         /* The "table" is actually a sub-select or a view in the FROM clause
         ** of the SELECT statement. Return the declaration type and origin
         ** data for the result-set column of the sub-select.
         */
-        if( ALWAYS(iCol>=0 && iCol<pS->pEList->nExpr) ){
+        if( iCol>=0 && ALWAYS(iCol<pS->pEList->nExpr) ){
           /* If iCol is less than zero, then the expression requests the
           ** rowid of the sub-select or view. This expression is legal (see 
           ** test case misc2.2.2) - it always evaluates to NULL.
@@ -73338,7 +94636,7 @@ static const char *columnType(
           NameContext sNC;
           Expr *p = pS->pEList->a[iCol].pExpr;
           sNC.pSrcList = pS->pSrc;
-          sNC.pNext = 0;
+          sNC.pNext = pNC;
           sNC.pParse = pNC->pParse;
           zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol); 
         }
@@ -73369,8 +94667,9 @@ static const char *columnType(
       ** statement.
       */
       NameContext sNC;
-      Select *pS = pExpr->pSelect;
+      Select *pS = pExpr->x.pSelect;
       Expr *p = pS->pEList->a[0].pExpr;
+      assert( ExprHasProperty(pExpr, EP_xIsSelect) );
       sNC.pSrcList = pS->pSrc;
       sNC.pNext = pNC;
       sNC.pParse = pNC->pParse;
@@ -73450,7 +94749,6 @@ static void generateColumnNames(
   }
 #endif
 
-  assert( v!=0 );
   if( pParse->colNamesSet || NEVER(v==0) || db->mallocFailed ) return;
   pParse->colNamesSet = 1;
   fullNames = (db->flags & SQLITE_FullColNames)!=0;
@@ -73459,7 +94757,7 @@ static void generateColumnNames(
   for(i=0; i<pEList->nExpr; i++){
     Expr *p;
     p = pEList->a[i].pExpr;
-    if( p==0 ) continue;
+    if( NEVER(p==0) ) continue;
     if( pEList->a[i].zName ){
       char *zName = pEList->a[i].zName;
       sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
@@ -73481,7 +94779,7 @@ static void generateColumnNames(
       }
       if( !shortNames && !fullNames ){
         sqlite3VdbeSetColName(v, i, COLNAME_NAME, 
-            sqlite3DbStrNDup(db, (char*)p->span.z, p->span.n), SQLITE_DYNAMIC);
+            sqlite3DbStrDup(db, pEList->a[i].zSpan), SQLITE_DYNAMIC);
       }else if( fullNames ){
         char *zName = 0;
         zName = sqlite3MPrintf(db, "%s.%s", pTab->zName, zCol);
@@ -73491,28 +94789,12 @@ static void generateColumnNames(
       }
     }else{
       sqlite3VdbeSetColName(v, i, COLNAME_NAME, 
-          sqlite3DbStrNDup(db, (char*)p->span.z, p->span.n), SQLITE_DYNAMIC);
+          sqlite3DbStrDup(db, pEList->a[i].zSpan), SQLITE_DYNAMIC);
     }
   }
   generateColumnTypes(pParse, pTabList, pEList);
 }
 
-#ifndef SQLITE_OMIT_COMPOUND_SELECT
-/*
-** Name of the connection operator, used for error messages.
-*/
-static const char *selectOpName(int id){
-  char *z;
-  switch( id ){
-    case TK_ALL:       z = "UNION ALL";   break;
-    case TK_INTERSECT: z = "INTERSECT";   break;
-    case TK_EXCEPT:    z = "EXCEPT";      break;
-    default:           z = "UNION";       break;
-  }
-  return z;
-}
-#endif /* SQLITE_OMIT_COMPOUND_SELECT */
-
 /*
 ** Given a an expression list (which is really the list of expressions
 ** that form the result set of a SELECT statement) compute appropriate
@@ -73541,38 +94823,52 @@ static int selectColumnsFromExprList(
   char *zName;                /* Column name */
   int nName;                  /* Size of name in zName[] */
 
-  *pnCol = nCol = pEList->nExpr;
-  aCol = *paCol = sqlite3DbMallocZero(db, sizeof(aCol[0])*nCol);
-  if( aCol==0 ) return SQLITE_NOMEM;
+  if( pEList ){
+    nCol = pEList->nExpr;
+    aCol = sqlite3DbMallocZero(db, sizeof(aCol[0])*nCol);
+    testcase( aCol==0 );
+  }else{
+    nCol = 0;
+    aCol = 0;
+  }
+  *pnCol = nCol;
+  *paCol = aCol;
+
   for(i=0, pCol=aCol; i<nCol; i++, pCol++){
     /* Get an appropriate name for the column
     */
     p = pEList->a[i].pExpr;
-    assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
+    assert( p->pRight==0 || ExprHasProperty(p->pRight, EP_IntValue)
+               || p->pRight->u.zToken==0 || p->pRight->u.zToken[0]!=0 );
     if( (zName = pEList->a[i].zName)!=0 ){
       /* If the column contains an "AS <name>" phrase, use <name> as the name */
       zName = sqlite3DbStrDup(db, zName);
     }else{
       Expr *pColExpr = p;  /* The expression that is the result column name */
       Table *pTab;         /* Table associated with this expression */
-      while( pColExpr->op==TK_DOT ) pColExpr = pColExpr->pRight;
-      if( pColExpr->op==TK_COLUMN && (pTab = pColExpr->pTab)!=0 ){
+      while( pColExpr->op==TK_DOT ){
+        pColExpr = pColExpr->pRight;
+        assert( pColExpr!=0 );
+      }
+      if( pColExpr->op==TK_COLUMN && ALWAYS(pColExpr->pTab!=0) ){
         /* For columns use the column name name */
         int iCol = pColExpr->iColumn;
+        pTab = pColExpr->pTab;
         if( iCol<0 ) iCol = pTab->iPKey;
         zName = sqlite3MPrintf(db, "%s",
                  iCol>=0 ? pTab->aCol[iCol].zName : "rowid");
+      }else if( pColExpr->op==TK_ID ){
+        assert( !ExprHasProperty(pColExpr, EP_IntValue) );
+        zName = sqlite3MPrintf(db, "%s", pColExpr->u.zToken);
       }else{
         /* Use the original text of the column expression as its name */
-        Token *pToken = (pColExpr->span.z?&pColExpr->span:&pColExpr->token);
-        zName = sqlite3MPrintf(db, "%T", pToken);
+        zName = sqlite3MPrintf(db, "%s", pEList->a[i].zSpan);
       }
     }
     if( db->mallocFailed ){
       sqlite3DbFree(db, zName);
       break;
     }
-    sqlite3Dequote(zName);
 
     /* Make sure the column name is unique.  If the name is not unique,
     ** append a integer to the name so that it becomes unique.
@@ -73611,7 +94907,7 @@ static int selectColumnsFromExprList(
 ** The column list has only names, not types or collations.  This
 ** routine goes through and adds the types and collations.
 **
-** This routine requires that all indentifiers in the SELECT
+** This routine requires that all identifiers in the SELECT
 ** statement be resolved.
 */
 static void selectAddColumnTypeAndCollation(
@@ -73639,6 +94935,7 @@ static void selectAddColumnTypeAndCollation(
     p = a[i].pExpr;
     pCol->zType = sqlite3DbStrDup(db, columnType(&sNC, p, 0, 0, 0));
     pCol->affinity = sqlite3ExprAffinity(p);
+    if( pCol->affinity==0 ) pCol->affinity = SQLITE_AFF_NONE;
     pColl = sqlite3ExprCollSeq(pParse, p);
     if( pColl ){
       pCol->zColl = sqlite3DbStrDup(db, pColl->zName);
@@ -73666,14 +94963,17 @@ SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse *pParse, Select *pSelect){
   if( pTab==0 ){
     return 0;
   }
-  pTab->db = db;
+  /* The sqlite3ResultSetOfSelect() is only used n contexts where lookaside
+  ** is disabled */
+  assert( db->lookaside.bEnabled==0 );
   pTab->nRef = 1;
   pTab->zName = 0;
+  pTab->nRowEst = 1000000;
   selectColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
   selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSelect);
   pTab->iPKey = -1;
   if( db->mallocFailed ){
-    sqlite3DeleteTable(pTab);
+    sqlite3DeleteTable(db, pTab);
     return 0;
   }
   return pTab;
@@ -73719,7 +95019,7 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
   Vdbe *v = 0;
   int iLimit = 0;
   int iOffset;
-  int addr1;
+  int addr1, n;
   if( p->iLimit ) return;
 
   /* 
@@ -73728,29 +95028,35 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
   ** The current implementation interprets "LIMIT 0" to mean
   ** no rows.
   */
+  sqlite3ExprCacheClear(pParse);
+  assert( p->pOffset==0 || p->pLimit!=0 );
   if( p->pLimit ){
     p->iLimit = iLimit = ++pParse->nMem;
     v = sqlite3GetVdbe(pParse);
-    if( v==0 ) return;
-    sqlite3ExprCode(pParse, p->pLimit, iLimit);
-    sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
-    VdbeComment((v, "LIMIT counter"));
-    sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
-  }
-  if( p->pOffset ){
-    p->iOffset = iOffset = ++pParse->nMem;
-    if( p->pLimit ){
-      pParse->nMem++;   /* Allocate an extra register for limit+offset */
+    if( NEVER(v==0) ) return;  /* VDBE should have already been allocated */
+    if( sqlite3ExprIsInteger(p->pLimit, &n) ){
+      sqlite3VdbeAddOp2(v, OP_Integer, n, iLimit);
+      VdbeComment((v, "LIMIT counter"));
+      if( n==0 ){
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, iBreak);
+      }else{
+        if( p->nSelectRow > (double)n ) p->nSelectRow = (double)n;
+      }
+    }else{
+      sqlite3ExprCode(pParse, p->pLimit, iLimit);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
+      VdbeComment((v, "LIMIT counter"));
+      sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
     }
-    v = sqlite3GetVdbe(pParse);
-    if( v==0 ) return;
-    sqlite3ExprCode(pParse, p->pOffset, iOffset);
-    sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
-    VdbeComment((v, "OFFSET counter"));
-    addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset);
-    sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
-    sqlite3VdbeJumpHere(v, addr1);
-    if( p->pLimit ){
+    if( p->pOffset ){
+      p->iOffset = iOffset = ++pParse->nMem;
+      pParse->nMem++;   /* Allocate an extra register for limit+offset */
+      sqlite3ExprCode(pParse, p->pOffset, iOffset);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
+      VdbeComment((v, "OFFSET counter"));
+      addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
+      sqlite3VdbeJumpHere(v, addr1);
       sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
       VdbeComment((v, "LIMIT+OFFSET"));
       addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
@@ -73776,7 +95082,8 @@ static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
   }else{
     pRet = 0;
   }
-  if( pRet==0 ){
+  assert( iCol>=0 );
+  if( pRet==0 && iCol<p->pEList->nExpr ){
     pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
   }
   return pRet;
@@ -73834,6 +95141,10 @@ static int multiSelect(
   SelectDest dest;      /* Alternative data destination */
   Select *pDelete = 0;  /* Chain of simple selects to delete */
   sqlite3 *db;          /* Database connection */
+#ifndef SQLITE_OMIT_EXPLAIN
+  int iSub1;            /* EQP id of left-hand query */
+  int iSub2;            /* EQP id of right-hand query */
+#endif
 
   /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
   ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
@@ -73864,7 +95175,8 @@ static int multiSelect(
   */
   if( dest.eDest==SRT_EphemTab ){
     assert( p->pEList );
-    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, p->pEList->nExpr);
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iSDParm, p->pEList->nExpr);
+    sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
     dest.eDest = SRT_Table;
   }
 
@@ -73873,8 +95185,12 @@ static int multiSelect(
   */
   assert( p->pEList && pPrior->pEList );
   if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
-    sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
-      " do not have the same number of result columns", selectOpName(p->op));
+    if( p->selFlags & SF_Values ){
+      sqlite3ErrorMsg(pParse, "all VALUES must have the same number of terms");
+    }else{
+      sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
+        " do not have the same number of result columns", selectOpName(p->op));
+    }
     rc = 1;
     goto multi_select_end;
   }
@@ -73890,9 +95206,11 @@ static int multiSelect(
   switch( p->op ){
     case TK_ALL: {
       int addr = 0;
+      int nLimit;
       assert( !pPrior->pLimit );
       pPrior->pLimit = p->pLimit;
       pPrior->pOffset = p->pOffset;
+      explainSetInteger(iSub1, pParse->iNextSelectId);
       rc = sqlite3Select(pParse, pPrior, &dest);
       p->pLimit = 0;
       p->pOffset = 0;
@@ -73906,11 +95224,17 @@ static int multiSelect(
         addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
         VdbeComment((v, "Jump ahead if LIMIT reached"));
       }
+      explainSetInteger(iSub2, pParse->iNextSelectId);
       rc = sqlite3Select(pParse, p, &dest);
+      testcase( rc!=SQLITE_OK );
       pDelete = p->pPrior;
       p->pPrior = pPrior;
-      if( rc ){
-        goto multi_select_end;
+      p->nSelectRow += pPrior->nSelectRow;
+      if( pPrior->pLimit
+       && sqlite3ExprIsInteger(pPrior->pLimit, &nLimit)
+       && p->nSelectRow > (double)nLimit 
+      ){
+        p->nSelectRow = (double)nLimit;
       }
       if( addr ){
         sqlite3VdbeJumpHere(v, addr);
@@ -73926,6 +95250,8 @@ static int multiSelect(
       int addr;
       SelectDest uniondest;
 
+      testcase( p->op==TK_EXCEPT );
+      testcase( p->op==TK_UNION );
       priorOp = SRT_Union;
       if( dest.eDest==priorOp && ALWAYS(!p->pLimit &&!p->pOffset) ){
         /* We can reuse a temporary table generated by a SELECT to our
@@ -73935,7 +95261,7 @@ static int multiSelect(
                                      ** of a 3-way or more compound */
         assert( p->pLimit==0 );      /* Not allowed on leftward elements */
         assert( p->pOffset==0 );     /* Not allowed on leftward elements */
-        unionTab = dest.iParm;
+        unionTab = dest.iSDParm;
       }else{
         /* We will need to create our own temporary table to hold the
         ** intermediate results.
@@ -73953,6 +95279,7 @@ static int multiSelect(
       */
       assert( !pPrior->pOrderBy );
       sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
+      explainSetInteger(iSub1, pParse->iNextSelectId);
       rc = sqlite3Select(pParse, pPrior, &uniondest);
       if( rc ){
         goto multi_select_end;
@@ -73972,27 +95299,27 @@ static int multiSelect(
       pOffset = p->pOffset;
       p->pOffset = 0;
       uniondest.eDest = op;
+      explainSetInteger(iSub2, pParse->iNextSelectId);
       rc = sqlite3Select(pParse, p, &uniondest);
+      testcase( rc!=SQLITE_OK );
       /* Query flattening in sqlite3Select() might refill p->pOrderBy.
       ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
       sqlite3ExprListDelete(db, p->pOrderBy);
       pDelete = p->pPrior;
       p->pPrior = pPrior;
       p->pOrderBy = 0;
+      if( p->op==TK_UNION ) p->nSelectRow += pPrior->nSelectRow;
       sqlite3ExprDelete(db, p->pLimit);
       p->pLimit = pLimit;
       p->pOffset = pOffset;
       p->iLimit = 0;
       p->iOffset = 0;
-      if( rc ){
-        goto multi_select_end;
-      }
-
 
       /* Convert the data in the temporary table into whatever form
       ** it is that we currently need.
-      */      
-      if( dest.eDest!=priorOp || unionTab!=dest.iParm ){
+      */
+      assert( unionTab==dest.iSDParm || dest.eDest!=priorOp );
+      if( dest.eDest!=priorOp ){
         int iCont, iBreak, iStart;
         assert( p->pEList );
         if( dest.eDest==SRT_Output ){
@@ -74014,7 +95341,7 @@ static int multiSelect(
       }
       break;
     }
-    case TK_INTERSECT: {
+    default: assert( p->op==TK_INTERSECT ); {
       int tab1, tab2;
       int iCont, iBreak, iStart;
       Expr *pLimit, *pOffset;
@@ -74039,6 +95366,7 @@ static int multiSelect(
       /* Code the SELECTs to our left into temporary table "tab1".
       */
       sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
+      explainSetInteger(iSub1, pParse->iNextSelectId);
       rc = sqlite3Select(pParse, pPrior, &intersectdest);
       if( rc ){
         goto multi_select_end;
@@ -74054,16 +95382,16 @@ static int multiSelect(
       p->pLimit = 0;
       pOffset = p->pOffset;
       p->pOffset = 0;
-      intersectdest.iParm = tab2;
+      intersectdest.iSDParm = tab2;
+      explainSetInteger(iSub2, pParse->iNextSelectId);
       rc = sqlite3Select(pParse, p, &intersectdest);
+      testcase( rc!=SQLITE_OK );
       pDelete = p->pPrior;
       p->pPrior = pPrior;
+      if( p->nSelectRow>pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
       sqlite3ExprDelete(db, p->pLimit);
       p->pLimit = pLimit;
       p->pOffset = pOffset;
-      if( rc ){
-        goto multi_select_end;
-      }
 
       /* Generate code to take the intersection of the two temporary
       ** tables.
@@ -74080,7 +95408,7 @@ static int multiSelect(
       sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
       r1 = sqlite3GetTempReg(pParse);
       iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
-      sqlite3VdbeAddOp3(v, OP_NotFound, tab2, iCont, r1);
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0);
       sqlite3ReleaseTempReg(pParse, r1);
       selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
                       0, -1, &dest, iCont, iBreak);
@@ -74093,6 +95421,8 @@ static int multiSelect(
     }
   }
 
+  explainComposite(pParse, p->op, iSub1, iSub2, p->op!=TK_ALL);
+
   /* Compute collating sequences used by 
   ** temporary tables needed to implement the compound select.
   ** Attach the KeyInfo structure to all temporary tables.
@@ -74146,8 +95476,8 @@ static int multiSelect(
   }
 
 multi_select_end:
-  pDest->iMem = dest.iMem;
-  pDest->nMem = dest.nMem;
+  pDest->iSdst = dest.iSdst;
+  pDest->nSdst = dest.nSdst;
   sqlite3SelectDelete(db, pDelete);
   return rc;
 }
@@ -74157,14 +95487,14 @@ multi_select_end:
 ** Code an output subroutine for a coroutine implementation of a
 ** SELECT statment.
 **
-** The data to be output is contained in pIn->iMem.  There are
-** pIn->nMem columns to be output.  pDest is where the output should
+** The data to be output is contained in pIn->iSdst.  There are
+** pIn->nSdst columns to be output.  pDest is where the output should
 ** be sent.
 **
 ** regReturn is the number of the register holding the subroutine
 ** return address.
 **
-** If regPrev>0 then it is a the first register in a vector that
+** If regPrev>0 then it is the first register in a vector that
 ** records the previous output.  mem[regPrev] is a flag that is false
 ** if there has been no previous output.  If regPrev>0 then code is
 ** generated to suppress duplicates.  pKeyInfo is used for comparing
@@ -74196,16 +95526,16 @@ static int generateOutputSubroutine(
   if( regPrev ){
     int j1, j2;
     j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
-    j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iMem, regPrev+1, pIn->nMem,
+    j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iSdst, regPrev+1, pIn->nSdst,
                               (char*)pKeyInfo, p4type);
     sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
     sqlite3VdbeJumpHere(v, j1);
-    sqlite3ExprCodeCopy(pParse, pIn->iMem, regPrev+1, pIn->nMem);
+    sqlite3ExprCodeCopy(pParse, pIn->iSdst, regPrev+1, pIn->nSdst);
     sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
   }
   if( pParse->db->mallocFailed ) return 0;
 
-  /* Suppress the the first OFFSET entries if there is an OFFSET clause
+  /* Suppress the first OFFSET entries if there is an OFFSET clause
   */
   codeOffset(v, p, iContinue);
 
@@ -74216,9 +95546,11 @@ static int generateOutputSubroutine(
     case SRT_EphemTab: {
       int r1 = sqlite3GetTempReg(pParse);
       int r2 = sqlite3GetTempReg(pParse);
-      sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iMem, pIn->nMem, r1);
-      sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iParm, r2);
-      sqlite3VdbeAddOp3(v, OP_Insert, pDest->iParm, r1, r2);
+      testcase( pDest->eDest==SRT_Table );
+      testcase( pDest->eDest==SRT_EphemTab );
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst, r1);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iSDParm, r2);
+      sqlite3VdbeAddOp3(v, OP_Insert, pDest->iSDParm, r1, r2);
       sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
       sqlite3ReleaseTempReg(pParse, r2);
       sqlite3ReleaseTempReg(pParse, r1);
@@ -74232,13 +95564,13 @@ static int generateOutputSubroutine(
     */
     case SRT_Set: {
       int r1;
-      assert( pIn->nMem==1 );
+      assert( pIn->nSdst==1 );
       p->affinity = 
-         sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affinity);
+         sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affSdst);
       r1 = sqlite3GetTempReg(pParse);
-      sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iMem, 1, r1, &p->affinity, 1);
-      sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, 1);
-      sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iParm, r1);
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, 1, r1, &p->affinity, 1);
+      sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, 1);
+      sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iSDParm, r1);
       sqlite3ReleaseTempReg(pParse, r1);
       break;
     }
@@ -74247,7 +95579,7 @@ static int generateOutputSubroutine(
     /* If any row exist in the result set, record that fact and abort.
     */
     case SRT_Exists: {
-      sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iParm);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iSDParm);
       /* The LIMIT clause will terminate the loop for us */
       break;
     }
@@ -74258,53 +95590,46 @@ static int generateOutputSubroutine(
     ** of the scan loop.
     */
     case SRT_Mem: {
-      assert( pIn->nMem==1 );
-      sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iParm, 1);
+      assert( pIn->nSdst==1 );
+      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSDParm, 1);
       /* The LIMIT clause will jump out of the loop for us */
       break;
     }
 #endif /* #ifndef SQLITE_OMIT_SUBQUERY */
 
     /* The results are stored in a sequence of registers
-    ** starting at pDest->iMem.  Then the co-routine yields.
+    ** starting at pDest->iSdst.  Then the co-routine yields.
     */
     case SRT_Coroutine: {
-      if( pDest->iMem==0 ){
-        pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
-        pDest->nMem = pIn->nMem;
+      if( pDest->iSdst==0 ){
+        pDest->iSdst = sqlite3GetTempRange(pParse, pIn->nSdst);
+        pDest->nSdst = pIn->nSdst;
       }
-      sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iMem, pDest->nMem);
-      sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
+      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSdst, pDest->nSdst);
+      sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
       break;
     }
 
-    /* Results are stored in a sequence of registers.  Then the
-    ** OP_ResultRow opcode is used to cause sqlite3_step() to return
-    ** the next row of result.
-    */
-    case SRT_Output: {
-      sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iMem, pIn->nMem);
-      sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, pIn->nMem);
-      break;
-    }
-
-#if !defined(SQLITE_OMIT_TRIGGER)
-    /* Discard the results.  This is used for SELECT statements inside
-    ** the body of a TRIGGER.  The purpose of such selects is to call
-    ** user-defined functions that have side effects.  We do not care
-    ** about the actual results of the select.
+    /* If none of the above, then the result destination must be
+    ** SRT_Output.  This routine is never called with any other
+    ** destination other than the ones handled above or SRT_Output.
+    **
+    ** For SRT_Output, results are stored in a sequence of registers.  
+    ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
+    ** return the next row of result.
     */
     default: {
+      assert( pDest->eDest==SRT_Output );
+      sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst);
+      sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, pIn->nSdst);
       break;
     }
-#endif
   }
 
   /* Jump to the end of the loop if the LIMIT is reached.
   */
   if( p->iLimit ){
-    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
-    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
+    sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
   }
 
   /* Generate the subroutine return
@@ -74441,12 +95766,16 @@ static int multiSelectOrderBy(
   ExprList *pOrderBy;   /* The ORDER BY clause */
   int nOrderBy;         /* Number of terms in the ORDER BY clause */
   int *aPermute;        /* Mapping from ORDER BY terms to result set columns */
+#ifndef SQLITE_OMIT_EXPLAIN
+  int iSub1;            /* EQP id of left-hand query */
+  int iSub2;            /* EQP id of right-hand query */
+#endif
 
   assert( p->pOrderBy!=0 );
   assert( pKeyDup==0 ); /* "Managed" code needs this.  Ticket #3382. */
   db = pParse->db;
   v = pParse->pVdbe;
-  if( v==0 ) return SQLITE_NOMEM;
+  assert( v!=0 );       /* Already thrown the error if VDBE alloc failed */
   labelEnd = sqlite3VdbeMakeLabel(v);
   labelCmpr = sqlite3VdbeMakeLabel(v);
 
@@ -74468,22 +95797,22 @@ static int multiSelectOrderBy(
     for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
       struct ExprList_item *pItem;
       for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
-        assert( pItem->iCol>0 );
-        if( pItem->iCol==i ) break;
+        assert( pItem->iOrderByCol>0 );
+        if( pItem->iOrderByCol==i ) break;
       }
       if( j==nOrderBy ){
-        Expr *pNew = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, 0);
+        Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
         if( pNew==0 ) return SQLITE_NOMEM;
         pNew->flags |= EP_IntValue;
-        pNew->iTable = i;
-        pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew, 0);
-        pOrderBy->a[nOrderBy++].iCol = (u16)i;
+        pNew->u.iValue = i;
+        pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew);
+        if( pOrderBy ) pOrderBy->a[nOrderBy++].iOrderByCol = (u16)i;
       }
     }
   }
 
   /* Compute the comparison permutation and keyinfo that is used with
-  ** the permutation in order to comparisons to determine if the next
+  ** the permutation used to determine if the next
   ** row of results comes from selectA or selectB.  Also add explicit
   ** collations to the ORDER BY clause terms so that when the subqueries
   ** to the right and the left are evaluated, they use the correct
@@ -74493,8 +95822,8 @@ static int multiSelectOrderBy(
   if( aPermute ){
     struct ExprList_item *pItem;
     for(i=0, pItem=pOrderBy->a; i<nOrderBy; i++, pItem++){
-      assert( pItem->iCol>0  && pItem->iCol<=p->pEList->nExpr );
-      aPermute[i] = pItem->iCol - 1;
+      assert( pItem->iOrderByCol>0  && pItem->iOrderByCol<=p->pEList->nExpr );
+      aPermute[i] = pItem->iOrderByCol - 1;
     }
     pKeyMerge =
       sqlite3DbMallocRaw(db, sizeof(*pKeyMerge)+nOrderBy*(sizeof(CollSeq*)+1));
@@ -74523,7 +95852,7 @@ static int multiSelectOrderBy(
   /* Reattach the ORDER BY clause to the query.
   */
   p->pOrderBy = pOrderBy;
-  pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy);
+  pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
 
   /* Allocate a range of temporary registers and the KeyInfo needed
   ** for the logic that removes duplicate result rows when the
@@ -74552,7 +95881,6 @@ static int multiSelectOrderBy(
   /* Separate the left and the right query from one another
   */
   p->pPrior = 0;
-  pPrior->pRightmost = 0;
   sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
   if( pPrior->pPrior==0 ){
     sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
@@ -74595,6 +95923,7 @@ static int multiSelectOrderBy(
   */
   VdbeNoopComment((v, "Begin coroutine for left SELECT"));
   pPrior->iLimit = regLimitA;
+  explainSetInteger(iSub1, pParse->iNextSelectId);
   sqlite3Select(pParse, pPrior, &destA);
   sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
   sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
@@ -74609,6 +95938,7 @@ static int multiSelectOrderBy(
   savedOffset = p->iOffset;
   p->iLimit = regLimitB;
   p->iOffset = 0;  
+  explainSetInteger(iSub2, pParse->iNextSelectId);
   sqlite3Select(pParse, p, &destB);
   p->iLimit = savedLimit;
   p->iOffset = savedOffset;
@@ -74645,6 +95975,7 @@ static int multiSelectOrderBy(
     sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
     sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
     sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
+    p->nSelectRow += pPrior->nSelectRow;
   }
 
   /* Generate a subroutine to run when the results from select B
@@ -74652,6 +95983,7 @@ static int multiSelectOrderBy(
   */
   if( op==TK_INTERSECT ){
     addrEofB = addrEofA;
+    if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
   }else{  
     VdbeNoopComment((v, "eof-B subroutine"));
     addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
@@ -74708,7 +96040,7 @@ static int multiSelectOrderBy(
   */
   sqlite3VdbeResolveLabel(v, labelCmpr);
   sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
-  sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, nOrderBy,
+  sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
                          (char*)pKeyMerge, P4_KEYINFO_HANDOFF);
   sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);
 
@@ -74739,6 +96071,7 @@ static int multiSelectOrderBy(
 
   /*** TBD:  Insert subroutine calls to close cursors on incomplete
   **** subqueries ****/
+  explainComposite(pParse, p->op, iSub1, iSub2, 0);
   return SQLITE_OK;
 }
 #endif
@@ -74761,46 +96094,37 @@ static void substSelect(sqlite3*, Select *, int, ExprList *);
 ** changes to pExpr so that it refers directly to the source table
 ** of the subquery rather the result set of the subquery.
 */
-static void substExpr(
+static Expr *substExpr(
   sqlite3 *db,        /* Report malloc errors to this connection */
   Expr *pExpr,        /* Expr in which substitution occurs */
   int iTable,         /* Table to be substituted */
   ExprList *pEList    /* Substitute expressions */
 ){
-  if( pExpr==0 ) return;
+  if( pExpr==0 ) return 0;
   if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
     if( pExpr->iColumn<0 ){
       pExpr->op = TK_NULL;
     }else{
       Expr *pNew;
       assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
-      assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
-      pNew = pEList->a[pExpr->iColumn].pExpr;
-      assert( pNew!=0 );
-      pExpr->op = pNew->op;
-      assert( pExpr->pLeft==0 );
-      pExpr->pLeft = sqlite3ExprDup(db, pNew->pLeft);
-      assert( pExpr->pRight==0 );
-      pExpr->pRight = sqlite3ExprDup(db, pNew->pRight);
-      assert( pExpr->pList==0 );
-      pExpr->pList = sqlite3ExprListDup(db, pNew->pList);
-      pExpr->iTable = pNew->iTable;
-      pExpr->pTab = pNew->pTab;
-      pExpr->iColumn = pNew->iColumn;
-      pExpr->iAgg = pNew->iAgg;
-      sqlite3TokenCopy(db, &pExpr->token, &pNew->token);
-      sqlite3TokenCopy(db, &pExpr->span, &pNew->span);
-      pExpr->pSelect = sqlite3SelectDup(db, pNew->pSelect);
-      pExpr->flags = pNew->flags;
-      pExpr->pAggInfo = pNew->pAggInfo;
-      pNew->pAggInfo = 0;
+      assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+      pNew = sqlite3ExprDup(db, pEList->a[pExpr->iColumn].pExpr, 0);
+      if( pNew && pExpr->pColl ){
+        pNew->pColl = pExpr->pColl;
+      }
+      sqlite3ExprDelete(db, pExpr);
+      pExpr = pNew;
     }
   }else{
-    substExpr(db, pExpr->pLeft, iTable, pEList);
-    substExpr(db, pExpr->pRight, iTable, pEList);
-    substSelect(db, pExpr->pSelect, iTable, pEList);
-    substExprList(db, pExpr->pList, iTable, pEList);
+    pExpr->pLeft = substExpr(db, pExpr->pLeft, iTable, pEList);
+    pExpr->pRight = substExpr(db, pExpr->pRight, iTable, pEList);
+    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+      substSelect(db, pExpr->x.pSelect, iTable, pEList);
+    }else{
+      substExprList(db, pExpr->x.pList, iTable, pEList);
+    }
   }
+  return pExpr;
 }
 static void substExprList(
   sqlite3 *db,         /* Report malloc errors here */
@@ -74811,7 +96135,7 @@ static void substExprList(
   int i;
   if( pList==0 ) return;
   for(i=0; i<pList->nExpr; i++){
-    substExpr(db, pList->a[i].pExpr, iTable, pEList);
+    pList->a[i].pExpr = substExpr(db, pList->a[i].pExpr, iTable, pEList);
   }
 }
 static void substSelect(
@@ -74827,8 +96151,8 @@ static void substSelect(
   substExprList(db, p->pEList, iTable, pEList);
   substExprList(db, p->pGroupBy, iTable, pEList);
   substExprList(db, p->pOrderBy, iTable, pEList);
-  substExpr(db, p->pHaving, iTable, pEList);
-  substExpr(db, p->pWhere, iTable, pEList);
+  p->pHaving = substExpr(db, p->pHaving, iTable, pEList);
+  p->pWhere = substExpr(db, p->pWhere, iTable, pEList);
   substSelect(db, p->pPrior, iTable, pEList);
   pSrc = p->pSrc;
   assert( pSrc );  /* Even for (SELECT 1) we have: pSrc!=0 but pSrc->nSrc==0 */
@@ -74842,9 +96166,8 @@ static void substSelect(
 
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
 /*
-** This routine attempts to flatten subqueries in order to speed
-** execution.  It returns 1 if it makes changes and 0 if no flattening
-** occurs.
+** This routine attempts to flatten subqueries as a performance optimization.
+** This routine returns 1 if it makes changes and 0 if no flattening occurs.
 **
 ** To understand the concept of flattening, consider the following
 ** query:
@@ -74875,17 +96198,21 @@ static void substSelect(
 **   (2)  The subquery is not an aggregate or the outer query is not a join.
 **
 **   (3)  The subquery is not the right operand of a left outer join
-**        (Originally ticket #306.  Strenghtened by ticket #3300)
+**        (Originally ticket #306.  Strengthened by ticket #3300)
 **
-**   (4)  The subquery is not DISTINCT or the outer query is not a join.
+**   (4)  The subquery is not DISTINCT.
 **
-**   (5)  The subquery is not DISTINCT or the outer query does not use
-**        aggregates.
+**  (**)  At one point restrictions (4) and (5) defined a subset of DISTINCT
+**        sub-queries that were excluded from this optimization. Restriction 
+**        (4) has since been expanded to exclude all DISTINCT subqueries.
 **
 **   (6)  The subquery does not use aggregates or the outer query is not
 **        DISTINCT.
 **
-**   (7)  The subquery has a FROM clause.
+**   (7)  The subquery has a FROM clause.  TODO:  For subqueries without
+**        A FROM clause, consider adding a FROM close with the special
+**        table sqlite_once that consists of a single row containing a
+**        single NULL.
 **
 **   (8)  The subquery does not use LIMIT or the outer query is not a join.
 **
@@ -74897,16 +96224,16 @@ static void substSelect(
 **
 **  (11)  The subquery and the outer query do not both have ORDER BY clauses.
 **
-**  (12)  Not implemented.  Subsumed into restriction (3).  Was previously
+**  (**)  Not implemented.  Subsumed into restriction (3).  Was previously
 **        a separate restriction deriving from ticket #350.
 **
-**  (13)  The subquery and outer query do not both use LIMIT
+**  (13)  The subquery and outer query do not both use LIMIT.
 **
-**  (14)  The subquery does not use OFFSET
+**  (14)  The subquery does not use OFFSET.
 **
 **  (15)  The outer query is not part of a compound select or the
-**        subquery does not have both an ORDER BY and a LIMIT clause.
-**        (See ticket #2339)
+**        subquery does not have a LIMIT clause.
+**        (See ticket #2339 and ticket [02a8e81d44]).
 **
 **  (16)  The outer query is not an aggregate or the subquery does
 **        not contain ORDER BY.  (Ticket #2942)  This used to not matter
@@ -74918,11 +96245,20 @@ static void substSelect(
 **
 **          * is not itself part of a compound select,
 **          * is not an aggregate or DISTINCT query, and
-**          * has no other tables or sub-selects in the FROM clause.
+**          * is not a join
 **
 **        The parent and sub-query may contain WHERE clauses. Subject to
 **        rules (11), (13) and (14), they may also contain ORDER BY,
-**        LIMIT and OFFSET clauses.
+**        LIMIT and OFFSET clauses.  The subquery cannot use any compound
+**        operator other than UNION ALL because all the other compound
+**        operators have an implied DISTINCT which is disallowed by
+**        restriction (4).
+**
+**        Also, each component of the sub-query must return the same number
+**        of result columns. This is actually a requirement for any compound
+**        SELECT statement, but all the code here does is make sure that no
+**        such (illegal) sub-query is flattened. The caller will detect the
+**        syntax error and return a detailed message.
 **
 **  (18)  If the sub-query is a compound select, then all terms of the
 **        ORDER by clause of the parent must be simple references to 
@@ -74931,6 +96267,15 @@ static void substSelect(
 **  (19)  The subquery does not use LIMIT or the outer query does not
 **        have a WHERE clause.
 **
+**  (20)  If the sub-query is a compound select, then it must not use
+**        an ORDER BY clause.  Ticket #3773.  We could relax this constraint
+**        somewhat by saying that the terms of the ORDER BY clause must
+**        appear as unmodified result columns in the outer query.  But we
+**        have other optimizations in mind to deal with that case.
+**
+**  (21)  The subquery does not use LIMIT or the outer query is not
+**        DISTINCT.  (See ticket [752e1646fc]).
+**
 ** In this routine, the "p" parameter is a pointer to the outer query.
 ** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query
 ** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
@@ -74965,6 +96310,7 @@ static int flattenSubquery(
   */
   assert( p!=0 );
   assert( p->pPrior==0 );  /* Unable to flatten compound queries */
+  if( db->flags & SQLITE_QueryFlattener ) return 0;
   pSrc = p->pSrc;
   assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
   pSubitem = &pSrc->a[iFrom];
@@ -74982,13 +96328,13 @@ static int flattenSubquery(
   ** and (14). */
   if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
   if( pSub->pOffset ) return 0;                          /* Restriction (14) */
-  if( p->pRightmost && pSub->pLimit && pSub->pOrderBy ){
+  if( p->pRightmost && pSub->pLimit ){
     return 0;                                            /* Restriction (15) */
   }
   if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
-  if( ((pSub->selFlags & SF_Distinct)!=0 || pSub->pLimit) 
-         && (pSrc->nSrc>1 || isAgg) ){          /* Restrictions (4)(5)(8)(9) */
-     return 0;       
+  if( pSub->selFlags & SF_Distinct ) return 0;           /* Restriction (5)  */
+  if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
+     return 0;         /* Restrictions (8)(9) */
   }
   if( (p->selFlags & SF_Distinct)!=0 && subqueryIsAgg ){
      return 0;         /* Restriction (6)  */
@@ -74998,6 +96344,9 @@ static int flattenSubquery(
   }
   if( isAgg && pSub->pOrderBy ) return 0;                /* Restriction (16) */
   if( pSub->pLimit && p->pWhere ) return 0;              /* Restriction (19) */
+  if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
+     return 0;         /* Restriction (21) */
+  }
 
   /* OBSOLETE COMMENT 1:
   ** Restriction 3:  If the subquery is a join, make sure the subquery is 
@@ -75041,23 +96390,31 @@ static int flattenSubquery(
   ** queries.
   */
   if( pSub->pPrior ){
+    if( pSub->pOrderBy ){
+      return 0;  /* Restriction 20 */
+    }
     if( isAgg || (p->selFlags & SF_Distinct)!=0 || pSrc->nSrc!=1 ){
       return 0;
     }
     for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
+      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
+      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
+      assert( pSub->pSrc!=0 );
       if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0
        || (pSub1->pPrior && pSub1->op!=TK_ALL) 
-       || !pSub1->pSrc || pSub1->pSrc->nSrc!=1
+       || pSub1->pSrc->nSrc<1
+       || pSub->pEList->nExpr!=pSub1->pEList->nExpr
       ){
         return 0;
       }
+      testcase( pSub1->pSrc->nSrc>1 );
     }
 
     /* Restriction 18. */
     if( p->pOrderBy ){
       int ii;
       for(ii=0; ii<p->pOrderBy->nExpr; ii++){
-        if( p->pOrderBy->a[ii].iCol==0 ) return 0;
+        if( p->pOrderBy->a[ii].iOrderByCol==0 ) return 0;
       }
     }
   }
@@ -75066,7 +96423,8 @@ static int flattenSubquery(
 
   /* Authorize the subquery */
   pParse->zAuthContext = pSubitem->zName;
-  sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
+  TESTONLY(i =) sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
+  testcase( i==SQLITE_DENY );
   pParse->zAuthContext = zSavedAuthContext;
 
   /* If the sub-query is a compound SELECT statement, then (by restrictions
@@ -75111,7 +96469,7 @@ static int flattenSubquery(
     p->pSrc = 0;
     p->pPrior = 0;
     p->pLimit = 0;
-    pNew = sqlite3SelectDup(db, p);
+    pNew = sqlite3SelectDup(db, p, 0);
     p->pLimit = pLimit;
     p->pOrderBy = pOrderBy;
     p->pSrc = pSrc;
@@ -75147,12 +96505,15 @@ static int flattenSubquery(
   ** subquery until code generation is
   ** complete, since there may still exist Expr.pTab entries that
   ** refer to the subquery even after flattening.  Ticket #3346.
+  **
+  ** pSubitem->pTab is always non-NULL by test restrictions and tests above.
   */
-  if( pSubitem->pTab!=0 ){
+  if( ALWAYS(pSubitem->pTab!=0) ){
     Table *pTabToDel = pSubitem->pTab;
     if( pTabToDel->nRef==1 ){
-      pTabToDel->pNextZombie = pParse->pZombieTab;
-      pParse->pZombieTab = pTabToDel;
+      Parse *pToplevel = sqlite3ParseToplevel(pParse);
+      pTabToDel->pNextZombie = pToplevel->pZombieTab;
+      pToplevel->pZombieTab = pTabToDel;
     }else{
       pTabToDel->nRef--;
     }
@@ -75217,6 +96578,7 @@ static int flattenSubquery(
     ** outer query.
     */
     for(i=0; i<nSubSrc; i++){
+      sqlite3IdListDelete(db, pSrc->a[i+iFrom].pUsing);
       pSrc->a[i+iFrom] = pSubSrc->a[i];
       memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
     }
@@ -75236,16 +96598,17 @@ static int flattenSubquery(
     */
     pList = pParent->pEList;
     for(i=0; i<pList->nExpr; i++){
-      Expr *pExpr;
-      if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
-        pList->a[i].zName = 
-               sqlite3DbStrNDup(db, (char*)pExpr->span.z, pExpr->span.n);
+      if( pList->a[i].zName==0 ){
+        const char *zSpan = pList->a[i].zSpan;
+        if( ALWAYS(zSpan) ){
+          pList->a[i].zName = sqlite3DbStrDup(db, zSpan);
+        }
       }
     }
     substExprList(db, pParent->pEList, iParent, pSub->pEList);
     if( isAgg ){
       substExprList(db, pParent->pGroupBy, iParent, pSub->pEList);
-      substExpr(db, pParent->pHaving, iParent, pSub->pEList);
+      pParent->pHaving = substExpr(db, pParent->pHaving, iParent, pSub->pEList);
     }
     if( pSub->pOrderBy ){
       assert( pParent->pOrderBy==0 );
@@ -75255,7 +96618,7 @@ static int flattenSubquery(
       substExprList(db, pParent->pOrderBy, iParent, pSub->pEList);
     }
     if( pSub->pWhere ){
-      pWhere = sqlite3ExprDup(db, pSub->pWhere);
+      pWhere = sqlite3ExprDup(db, pSub->pWhere, 0);
     }else{
       pWhere = 0;
     }
@@ -75263,13 +96626,13 @@ static int flattenSubquery(
       assert( pParent->pHaving==0 );
       pParent->pHaving = pParent->pWhere;
       pParent->pWhere = pWhere;
-      substExpr(db, pParent->pHaving, iParent, pSub->pEList);
+      pParent->pHaving = substExpr(db, pParent->pHaving, iParent, pSub->pEList);
       pParent->pHaving = sqlite3ExprAnd(db, pParent->pHaving, 
-                                  sqlite3ExprDup(db, pSub->pHaving));
+                                  sqlite3ExprDup(db, pSub->pHaving, 0));
       assert( pParent->pGroupBy==0 );
-      pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy);
+      pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy, 0);
     }else{
-      substExpr(db, pParent->pWhere, iParent, pSub->pEList);
+      pParent->pWhere = substExpr(db, pParent->pWhere, iParent, pSub->pEList);
       pParent->pWhere = sqlite3ExprAnd(db, pParent->pWhere, pWhere);
     }
   
@@ -75316,18 +96679,55 @@ static u8 minMaxQuery(Select *p){
 
   if( pEList->nExpr!=1 ) return WHERE_ORDERBY_NORMAL;
   pExpr = pEList->a[0].pExpr;
-  pEList = pExpr->pList;
-  if( pExpr->op!=TK_AGG_FUNCTION || pEList==0 || pEList->nExpr!=1 ) return 0;
+  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
+  if( NEVER(ExprHasProperty(pExpr, EP_xIsSelect)) ) return 0;
+  pEList = pExpr->x.pList;
+  if( pEList==0 || pEList->nExpr!=1 ) return 0;
   if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return WHERE_ORDERBY_NORMAL;
-  if( pExpr->token.n!=3 ) return WHERE_ORDERBY_NORMAL;
-  if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
+  assert( !ExprHasProperty(pExpr, EP_IntValue) );
+  if( sqlite3StrICmp(pExpr->u.zToken,"min")==0 ){
     return WHERE_ORDERBY_MIN;
-  }else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
+  }else if( sqlite3StrICmp(pExpr->u.zToken,"max")==0 ){
     return WHERE_ORDERBY_MAX;
   }
   return WHERE_ORDERBY_NORMAL;
 }
 
+/*
+** The select statement passed as the first argument is an aggregate query.
+** The second argment is the associated aggregate-info object. This 
+** function tests if the SELECT is of the form:
+**
+**   SELECT count(*) FROM <tbl>
+**
+** where table is a database table, not a sub-select or view. If the query
+** does match this pattern, then a pointer to the Table object representing
+** <tbl> is returned. Otherwise, 0 is returned.
+*/
+static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
+  Table *pTab;
+  Expr *pExpr;
+
+  assert( !p->pGroupBy );
+
+  if( p->pWhere || p->pEList->nExpr!=1 
+   || p->pSrc->nSrc!=1 || p->pSrc->a[0].pSelect
+  ){
+    return 0;
+  }
+  pTab = p->pSrc->a[0].pTab;
+  pExpr = p->pEList->a[0].pExpr;
+  assert( pTab && !pTab->pSelect && pExpr );
+
+  if( IsVirtual(pTab) ) return 0;
+  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
+  if( NEVER(pAggInfo->nFunc==0) ) return 0;
+  if( (pAggInfo->aFunc[0].pFunc->flags&SQLITE_FUNC_COUNT)==0 ) return 0;
+  if( pExpr->flags&EP_Distinct ) return 0;
+
+  return pTab;
+}
+
 /*
 ** If the source-list item passed as an argument was augmented with an
 ** INDEXED BY clause, then try to locate the specified index. If there
@@ -75346,6 +96746,7 @@ SQLITE_PRIVATE int sqlite3IndexedByLookup(Parse *pParse, struct SrcList_item *pF
     );
     if( !pIdx ){
       sqlite3ErrorMsg(pParse, "no such index: %s", zIndex, 0);
+      pParse->checkSchema = 1;
       return SQLITE_ERROR;
     }
     pFrom->pIndex = pIdx;
@@ -75388,7 +96789,7 @@ static int selectExpander(Walker *pWalker, Select *p){
   if( db->mallocFailed  ){
     return WRC_Abort;
   }
-  if( p->pSrc==0 || (p->selFlags & SF_Expanded)!=0 ){
+  if( NEVER(p->pSrc==0) || (p->selFlags & SF_Expanded)!=0 ){
     return WRC_Prune;
   }
   p->selFlags |= SF_Expanded;
@@ -75421,12 +96822,12 @@ static int selectExpander(Walker *pWalker, Select *p){
       sqlite3WalkSelect(pWalker, pSel);
       pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
       if( pTab==0 ) return WRC_Abort;
-      pTab->db = db;
       pTab->nRef = 1;
       pTab->zName = sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pTab);
       while( pSel->pPrior ){ pSel = pSel->pPrior; }
       selectColumnsFromExprList(pParse, pSel->pEList, &pTab->nCol, &pTab->aCol);
       pTab->iPKey = -1;
+      pTab->nRowEst = 1000000;
       pTab->tabFlags |= TF_Ephemeral;
 #endif
     }else{
@@ -75440,16 +96841,9 @@ static int selectExpander(Walker *pWalker, Select *p){
       if( pTab->pSelect || IsVirtual(pTab) ){
         /* We reach here if the named table is a really a view */
         if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
-
-        /* If pFrom->pSelect!=0 it means we are dealing with a
-        ** view within a view.  The SELECT structure has already been
-        ** copied by the outer view so we can skip the copy step here
-        ** in the inner view.
-        */
-        if( pFrom->pSelect==0 ){
-          pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect);
-          sqlite3WalkSelect(pWalker, pFrom->pSelect);
-        }
+        assert( pFrom->pSelect==0 );
+        pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect, 0);
+        sqlite3WalkSelect(pWalker, pFrom->pSelect);
       }
 #endif
     }
@@ -75479,8 +96873,9 @@ static int selectExpander(Walker *pWalker, Select *p){
   for(k=0; k<pEList->nExpr; k++){
     Expr *pE = pEList->a[k].pExpr;
     if( pE->op==TK_ALL ) break;
-    if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
-         && pE->pLeft && pE->pLeft->op==TK_ID ) break;
+    assert( pE->op!=TK_DOT || pE->pRight!=0 );
+    assert( pE->op!=TK_DOT || (pE->pLeft!=0 && pE->pLeft->op==TK_ID) );
+    if( pE->op==TK_DOT && pE->pRight->op==TK_ALL ) break;
   }
   if( k<pEList->nExpr ){
     /*
@@ -75496,30 +96891,34 @@ static int selectExpander(Walker *pWalker, Select *p){
 
     for(k=0; k<pEList->nExpr; k++){
       Expr *pE = a[k].pExpr;
-      if( pE->op!=TK_ALL &&
-           (pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
+      assert( pE->op!=TK_DOT || pE->pRight!=0 );
+      if( pE->op!=TK_ALL && (pE->op!=TK_DOT || pE->pRight->op!=TK_ALL) ){
         /* This particular expression does not need to be expanded.
         */
-        pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr, 0);
+        pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr);
         if( pNew ){
           pNew->a[pNew->nExpr-1].zName = a[k].zName;
+          pNew->a[pNew->nExpr-1].zSpan = a[k].zSpan;
+          a[k].zName = 0;
+          a[k].zSpan = 0;
         }
         a[k].pExpr = 0;
-        a[k].zName = 0;
       }else{
         /* This expression is a "*" or a "TABLE.*" and needs to be
         ** expanded. */
         int tableSeen = 0;      /* Set to 1 when TABLE matches */
         char *zTName;            /* text of name of TABLE */
-        if( pE->op==TK_DOT && pE->pLeft ){
-          zTName = sqlite3NameFromToken(db, &pE->pLeft->token);
+        if( pE->op==TK_DOT ){
+          assert( pE->pLeft!=0 );
+          assert( !ExprHasProperty(pE->pLeft, EP_IntValue) );
+          zTName = pE->pLeft->u.zToken;
         }else{
           zTName = 0;
         }
         for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
           Table *pTab = pFrom->pTab;
           char *zTabName = pFrom->zAlias;
-          if( zTabName==0 || zTabName[0]==0 ){ 
+          if( zTabName==0 ){
             zTabName = pTab->zName;
           }
           if( db->mallocFailed ) break;
@@ -75530,6 +96929,9 @@ static int selectExpander(Walker *pWalker, Select *p){
           for(j=0; j<pTab->nCol; j++){
             Expr *pExpr, *pRight;
             char *zName = pTab->aCol[j].zName;
+            char *zColname;  /* The computed column name */
+            char *zToFree;   /* Malloced string that needs to be freed */
+            Token sColname;  /* Computed column name as a token */
 
             /* If a column is marked as 'hidden' (currently only possible
             ** for virtual tables), do not include it in the expanded
@@ -75541,43 +96943,38 @@ static int selectExpander(Walker *pWalker, Select *p){
             }
 
             if( i>0 && zTName==0 ){
-              struct SrcList_item *pLeft = &pTabList->a[i-1];
-              if( (pLeft[1].jointype & JT_NATURAL)!=0 &&
-                        columnIndex(pLeft->pTab, zName)>=0 ){
+              if( (pFrom->jointype & JT_NATURAL)!=0
+                && tableAndColumnIndex(pTabList, i, zName, 0, 0)
+              ){
                 /* In a NATURAL join, omit the join columns from the 
-                ** table on the right */
+                ** table to the right of the join */
                 continue;
               }
-              if( sqlite3IdListIndex(pLeft[1].pUsing, zName)>=0 ){
+              if( sqlite3IdListIndex(pFrom->pUsing, zName)>=0 ){
                 /* In a join with a USING clause, omit columns in the
                 ** using clause from the table on the right. */
                 continue;
               }
             }
-            pRight = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
-            if( pRight==0 ) break;
-            setQuotedToken(pParse, &pRight->token, zName);
+            pRight = sqlite3Expr(db, TK_ID, zName);
+            zColname = zName;
+            zToFree = 0;
             if( longNames || pTabList->nSrc>1 ){
-              Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
+              Expr *pLeft;
+              pLeft = sqlite3Expr(db, TK_ID, zTabName);
               pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
-              if( pExpr==0 ) break;
-              setQuotedToken(pParse, &pLeft->token, zTabName);
-              setToken(&pExpr->span, 
-                  sqlite3MPrintf(db, "%s.%s", zTabName, zName));
-              pExpr->span.dyn = 1;
-              pExpr->token.z = 0;
-              pExpr->token.n = 0;
-              pExpr->token.dyn = 0;
+              if( longNames ){
+                zColname = sqlite3MPrintf(db, "%s.%s", zTabName, zName);
+                zToFree = zColname;
+              }
             }else{
               pExpr = pRight;
-              pExpr->span = pExpr->token;
-              pExpr->span.dyn = 0;
-            }
-            if( longNames ){
-              pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pExpr->span);
-            }else{
-              pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pRight->token);
             }
+            pNew = sqlite3ExprListAppend(pParse, pNew, pExpr);
+            sColname.z = zColname;
+            sColname.n = sqlite3Strlen30(zColname);
+            sqlite3ExprListSetName(pParse, pNew, &sColname, 0);
+            sqlite3DbFree(db, zToFree);
           }
         }
         if( !tableSeen ){
@@ -75587,7 +96984,6 @@ static int selectExpander(Walker *pWalker, Select *p){
             sqlite3ErrorMsg(pParse, "no tables specified");
           }
         }
-        sqlite3DbFree(db, zTName);
       }
     }
     sqlite3ExprListDelete(db, pEList);
@@ -75664,7 +97060,7 @@ static int selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
     pTabList = p->pSrc;
     for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
       Table *pTab = pFrom->pTab;
-      if( pTab && (pTab->tabFlags & TF_Ephemeral)!=0 ){
+      if( ALWAYS(pTab!=0) && (pTab->tabFlags & TF_Ephemeral)!=0 ){
         /* A sub-query in the FROM clause of a SELECT */
         Select *pSel = pFrom->pSelect;
         assert( pSel );
@@ -75697,7 +97093,7 @@ static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
 
 
 /*
-** This routine sets of a SELECT statement for processing.  The
+** This routine sets up a SELECT statement for processing.  The
 ** following is accomplished:
 **
 **     *  VDBE Cursor numbers are assigned to all FROM-clause terms.
@@ -75714,10 +97110,9 @@ SQLITE_PRIVATE void sqlite3SelectPrep(
   NameContext *pOuterNC  /* Name context for container */
 ){
   sqlite3 *db;
-  if( p==0 ) return;
+  if( NEVER(p==0) ) return;
   db = pParse->db;
   if( p->selFlags & SF_HasTypeInfo ) return;
-  if( pParse->nErr || db->mallocFailed ) return;
   sqlite3SelectExpand(pParse, p);
   if( pParse->nErr || db->mallocFailed ) return;
   sqlite3ResolveSelectNames(pParse, p, pOuterNC);
@@ -75730,7 +97125,8 @@ SQLITE_PRIVATE void sqlite3SelectPrep(
 **
 ** The aggregate accumulator is a set of memory cells that hold
 ** intermediate results while calculating an aggregate.  This
-** routine simply stores NULLs in all of those memory cells.
+** routine generates code that stores NULLs in all of those memory
+** cells.
 */
 static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
   Vdbe *v = pParse->pVdbe;
@@ -75746,12 +97142,13 @@ static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
     sqlite3VdbeAddOp2(v, OP_Null, 0, pFunc->iMem);
     if( pFunc->iDistinct>=0 ){
       Expr *pE = pFunc->pExpr;
-      if( pE->pList==0 || pE->pList->nExpr!=1 ){
-        sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
-           "by an expression");
+      assert( !ExprHasProperty(pE, EP_xIsSelect) );
+      if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){
+        sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one "
+           "argument");
         pFunc->iDistinct = -1;
       }else{
-        KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
+        KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->x.pList);
         sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
                           (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
       }
@@ -75768,7 +97165,8 @@ static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
   int i;
   struct AggInfo_func *pF;
   for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
-    ExprList *pList = pF->pExpr->pList;
+    ExprList *pList = pF->pExpr->x.pList;
+    assert( !ExprHasProperty(pF->pExpr, EP_xIsSelect) );
     sqlite3VdbeAddOp4(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0, 0,
                       (void*)pF->pFunc, P4_FUNCDEF);
   }
@@ -75781,19 +97179,23 @@ static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
 static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
   Vdbe *v = pParse->pVdbe;
   int i;
+  int regHit = 0;
+  int addrHitTest = 0;
   struct AggInfo_func *pF;
   struct AggInfo_col *pC;
 
   pAggInfo->directMode = 1;
+  sqlite3ExprCacheClear(pParse);
   for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
     int nArg;
     int addrNext = 0;
     int regAgg;
-    ExprList *pList = pF->pExpr->pList;
+    ExprList *pList = pF->pExpr->x.pList;
+    assert( !ExprHasProperty(pF->pExpr, EP_xIsSelect) );
     if( pList ){
       nArg = pList->nExpr;
       regAgg = sqlite3GetTempRange(pParse, nArg);
-      sqlite3ExprCodeExprList(pParse, pList, regAgg, 0);
+      sqlite3ExprCodeExprList(pParse, pList, regAgg, 1);
     }else{
       nArg = 0;
       regAgg = 0;
@@ -75814,23 +97216,70 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
       if( !pColl ){
         pColl = pParse->db->pDfltColl;
       }
-      sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
+      if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem;
+      sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0, (char *)pColl, P4_COLLSEQ);
     }
     sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
                       (void*)pF->pFunc, P4_FUNCDEF);
     sqlite3VdbeChangeP5(v, (u8)nArg);
-    sqlite3ReleaseTempRange(pParse, regAgg, nArg);
     sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
+    sqlite3ReleaseTempRange(pParse, regAgg, nArg);
     if( addrNext ){
       sqlite3VdbeResolveLabel(v, addrNext);
+      sqlite3ExprCacheClear(pParse);
     }
   }
+
+  /* Before populating the accumulator registers, clear the column cache.
+  ** Otherwise, if any of the required column values are already present 
+  ** in registers, sqlite3ExprCode() may use OP_SCopy to copy the value
+  ** to pC->iMem. But by the time the value is used, the original register
+  ** may have been used, invalidating the underlying buffer holding the
+  ** text or blob value. See ticket [883034dcb5].
+  **
+  ** Another solution would be to change the OP_SCopy used to copy cached
+  ** values to an OP_Copy.
+  */
+  if( regHit ){
+    addrHitTest = sqlite3VdbeAddOp1(v, OP_If, regHit);
+  }
+  sqlite3ExprCacheClear(pParse);
   for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
     sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
   }
   pAggInfo->directMode = 0;
+  sqlite3ExprCacheClear(pParse);
+  if( addrHitTest ){
+    sqlite3VdbeJumpHere(v, addrHitTest);
+  }
 }
 
+/*
+** Add a single OP_Explain instruction to the VDBE to explain a simple
+** count(*) query ("SELECT count(*) FROM pTab").
+*/
+#ifndef SQLITE_OMIT_EXPLAIN
+static void explainSimpleCount(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being queried */
+  Index *pIdx                     /* Index used to optimize scan, or NULL */
+){
+  if( pParse->explain==2 ){
+    char *zEqp = sqlite3MPrintf(pParse->db, "SCAN TABLE %s %s%s(~%d rows)",
+        pTab->zName, 
+        pIdx ? "USING COVERING INDEX " : "",
+        pIdx ? pIdx->zName : "",
+        pTab->nRowEst
+    );
+    sqlite3VdbeAddOp4(
+        pParse->pVdbe, OP_Explain, pParse->iSelectId, 0, 0, zEqp, P4_DYNAMIC
+    );
+  }
+}
+#else
+# define explainSimpleCount(a,b,c)
+#endif
+
 /*
 ** Generate code for the SELECT statement given in the p argument.  
 **
@@ -75845,23 +97294,24 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
 **
 **     SRT_Mem         Only valid if the result is a single column.
 **                     Store the first column of the first result row
-**                     in register pDest->iParm then abandon the rest
+**                     in register pDest->iSDParm then abandon the rest
 **                     of the query.  This destination implies "LIMIT 1".
 **
 **     SRT_Set         The result must be a single column.  Store each
-**                     row of result as the key in table pDest->iParm. 
-**                     Apply the affinity pDest->affinity before storing
+**                     row of result as the key in table pDest->iSDParm. 
+**                     Apply the affinity pDest->affSdst before storing
 **                     results.  Used to implement "IN (SELECT ...)".
 **
-**     SRT_Union       Store results as a key in a temporary table pDest->iParm.
+**     SRT_Union       Store results as a key in a temporary table 
+**                     identified by pDest->iSDParm.
 **
-**     SRT_Except      Remove results from the temporary table pDest->iParm.
+**     SRT_Except      Remove results from the temporary table pDest->iSDParm.
 **
-**     SRT_Table       Store results in temporary table pDest->iParm.
+**     SRT_Table       Store results in temporary table pDest->iSDParm.
 **                     This is like SRT_EphemTab except that the table
 **                     is assumed to already be open.
 **
-**     SRT_EphemTab    Create an temporary table pDest->iParm and store
+**     SRT_EphemTab    Create an temporary table pDest->iSDParm and store
 **                     the result there. The cursor is left open after
 **                     returning.  This is like SRT_Table except that
 **                     this destination uses OP_OpenEphemeral to create
@@ -75869,9 +97319,9 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
 **
 **     SRT_Coroutine   Generate a co-routine that returns a new row of
 **                     results each time it is invoked.  The entry point
-**                     of the co-routine is stored in register pDest->iParm.
+**                     of the co-routine is stored in register pDest->iSDParm.
 **
-**     SRT_Exists      Store a 1 in memory cell pDest->iParm if the result
+**     SRT_Exists      Store a 1 in memory cell pDest->iSDParm if the result
 **                     set is not empty.
 **
 **     SRT_Discard     Throw the results away.  This is used by SELECT
@@ -75904,10 +97354,16 @@ SQLITE_PRIVATE int sqlite3Select(
   int distinct;          /* Table to use for the distinct set */
   int rc = 1;            /* Value to return from this function */
   int addrSortIndex;     /* Address of an OP_OpenEphemeral instruction */
+  int addrDistinctIndex; /* Address of an OP_OpenEphemeral instruction */
   AggInfo sAggInfo;      /* Information used by aggregate queries */
   int iEnd;              /* Address of the end of the query */
   sqlite3 *db;           /* The database connection */
 
+#ifndef SQLITE_OMIT_EXPLAIN
+  int iRestoreSelectId = pParse->iSelectId;
+  pParse->iSelectId = pParse->iNextSelectId++;
+#endif
+
   db = pParse->db;
   if( p==0 || db->mallocFailed || pParse->nErr ){
     return 1;
@@ -75915,44 +97371,39 @@ SQLITE_PRIVATE int sqlite3Select(
   if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
   memset(&sAggInfo, 0, sizeof(sAggInfo));
 
-  pOrderBy = p->pOrderBy;
   if( IgnorableOrderby(pDest) ){
-    p->pOrderBy = 0;
-
-    /* In these cases the DISTINCT operator makes no difference to the
-    ** results, so remove it if it were specified.
-    */
     assert(pDest->eDest==SRT_Exists || pDest->eDest==SRT_Union || 
            pDest->eDest==SRT_Except || pDest->eDest==SRT_Discard);
+    /* If ORDER BY makes no difference in the output then neither does
+    ** DISTINCT so it can be removed too. */
+    sqlite3ExprListDelete(db, p->pOrderBy);
+    p->pOrderBy = 0;
     p->selFlags &= ~SF_Distinct;
   }
   sqlite3SelectPrep(pParse, p, 0);
+  pOrderBy = p->pOrderBy;
   pTabList = p->pSrc;
   pEList = p->pEList;
   if( pParse->nErr || db->mallocFailed ){
     goto select_end;
   }
-  p->pOrderBy = pOrderBy;
   isAgg = (p->selFlags & SF_Aggregate)!=0;
-  if( pEList==0 ) goto select_end;
-
-  /* 
-  ** Do not even attempt to generate any code if we have already seen
-  ** errors before this routine starts.
-  */
-  if( pParse->nErr>0 ) goto select_end;
-
-  /* ORDER BY is ignored for some destinations.
-  */
-  if( IgnorableOrderby(pDest) ){
-    pOrderBy = 0;
-  }
+  assert( pEList!=0 );
 
   /* Begin generating code.
   */
   v = sqlite3GetVdbe(pParse);
   if( v==0 ) goto select_end;
 
+  /* If writing to memory or generating a set
+  ** only a single column may be output.
+  */
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
+    goto select_end;
+  }
+#endif
+
   /* Generate code for all sub-queries in the FROM clause
   */
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
@@ -75962,7 +97413,11 @@ SQLITE_PRIVATE int sqlite3Select(
     Select *pSub = pItem->pSelect;
     int isAggSub;
 
-    if( pSub==0 || pItem->isPopulated ) continue;
+    if( pSub==0 ) continue;
+    if( pItem->addrFillSub ){
+      sqlite3VdbeAddOp2(v, OP_Gosub, pItem->regReturn, pItem->addrFillSub);
+      continue;
+    }
 
     /* Increment Parse.nHeight by the height of the largest expression
     ** tree refered to by this, the parent select. The child select
@@ -75973,21 +97428,45 @@ SQLITE_PRIVATE int sqlite3Select(
     */
     pParse->nHeight += sqlite3SelectExprHeight(p);
 
-    /* Check to see if the subquery can be absorbed into the parent. */
     isAggSub = (pSub->selFlags & SF_Aggregate)!=0;
     if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
+      /* This subquery can be absorbed into its parent. */
       if( isAggSub ){
         isAgg = 1;
         p->selFlags |= SF_Aggregate;
       }
       i = -1;
     }else{
+      /* Generate a subroutine that will fill an ephemeral table with
+      ** the content of this subquery.  pItem->addrFillSub will point
+      ** to the address of the generated subroutine.  pItem->regReturn
+      ** is a register allocated to hold the subroutine return address
+      */
+      int topAddr;
+      int onceAddr = 0;
+      int retAddr;
+      assert( pItem->addrFillSub==0 );
+      pItem->regReturn = ++pParse->nMem;
+      topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
+      pItem->addrFillSub = topAddr+1;
+      VdbeNoopComment((v, "materialize %s", pItem->pTab->zName));
+      if( pItem->isCorrelated==0 ){
+        /* If the subquery is no correlated and if we are not inside of
+        ** a trigger, then we only need to compute the value of the subquery
+        ** once. */
+        onceAddr = sqlite3CodeOnce(pParse);
+      }
       sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
-      assert( pItem->isPopulated==0 );
+      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
       sqlite3Select(pParse, pSub, &dest);
-      pItem->isPopulated = 1;
+      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
+      if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
+      retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
+      VdbeComment((v, "end %s", pItem->pTab->zName));
+      sqlite3VdbeChangeP1(v, topAddr, retAddr);
+      sqlite3ClearTempRegCache(pParse);
     }
-    if( pParse->nErr || db->mallocFailed ){
+    if( /*pParse->nErr ||*/ db->mallocFailed ){
       goto select_end;
     }
     pParse->nHeight -= sqlite3SelectExprHeight(p);
@@ -76019,30 +97498,49 @@ SQLITE_PRIVATE int sqlite3Select(
       mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
       if( mxSelect && cnt>mxSelect ){
         sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
-        return 1;
+        goto select_end;
       }
     }
-    return multiSelect(pParse, p, pDest);
+    rc = multiSelect(pParse, p, pDest);
+    explainSetInteger(pParse->iSelectId, iRestoreSelectId);
+    return rc;
   }
 #endif
 
-  /* If writing to memory or generating a set
-  ** only a single column may be output.
+  /* If there is both a GROUP BY and an ORDER BY clause and they are
+  ** identical, then disable the ORDER BY clause since the GROUP BY
+  ** will cause elements to come out in the correct order.  This is
+  ** an optimization - the correct answer should result regardless.
+  ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER
+  ** to disable this optimization for testing purposes.
   */
-#ifndef SQLITE_OMIT_SUBQUERY
-  if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
-    goto select_end;
+  if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy)==0
+         && (db->flags & SQLITE_GroupByOrder)==0 ){
+    pOrderBy = 0;
   }
-#endif
 
-  /* If possible, rewrite the query to use GROUP BY instead of DISTINCT.
-  ** GROUP BY might use an index, DISTINCT never does.
+  /* If the query is DISTINCT with an ORDER BY but is not an aggregate, and 
+  ** if the select-list is the same as the ORDER BY list, then this query
+  ** can be rewritten as a GROUP BY. In other words, this:
+  **
+  **     SELECT DISTINCT xyz FROM ... ORDER BY xyz
+  **
+  ** is transformed to:
+  **
+  **     SELECT xyz FROM ... GROUP BY xyz
+  **
+  ** The second form is preferred as a single index (or temp-table) may be 
+  ** used for both the ORDER BY and DISTINCT processing. As originally 
+  ** written the query must use a temp-table for at least one of the ORDER 
+  ** BY and DISTINCT, and an index or separate temp-table for the other.
   */
-  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct && !p->pGroupBy ){
-    p->pGroupBy = sqlite3ExprListDup(db, p->pEList);
-    pGroupBy = p->pGroupBy;
+  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct 
+   && sqlite3ExprListCompare(pOrderBy, p->pEList)==0
+  ){
     p->selFlags &= ~SF_Distinct;
-    isDistinct = 0;
+    p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0);
+    pGroupBy = p->pGroupBy;
+    pOrderBy = 0;
   }
 
   /* If there is an ORDER BY clause, then this sorting
@@ -76067,48 +97565,96 @@ SQLITE_PRIVATE int sqlite3Select(
   /* If the output is destined for a temporary table, open that table.
   */
   if( pDest->eDest==SRT_EphemTab ){
-    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iParm, pEList->nExpr);
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iSDParm, pEList->nExpr);
   }
 
   /* Set the limiter.
   */
   iEnd = sqlite3VdbeMakeLabel(v);
+  p->nSelectRow = (double)LARGEST_INT64;
   computeLimitRegisters(pParse, p, iEnd);
+  if( p->iLimit==0 && addrSortIndex>=0 ){
+    sqlite3VdbeGetOp(v, addrSortIndex)->opcode = OP_SorterOpen;
+    p->selFlags |= SF_UseSorter;
+  }
 
   /* Open a virtual index to use for the distinct set.
   */
-  if( isDistinct ){
+  if( p->selFlags & SF_Distinct ){
     KeyInfo *pKeyInfo;
-    assert( isAgg || pGroupBy );
     distinct = pParse->nTab++;
     pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
-    sqlite3VdbeAddOp4(v, OP_OpenEphemeral, distinct, 0, 0,
-                        (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+    addrDistinctIndex = sqlite3VdbeAddOp4(v, OP_OpenEphemeral, distinct, 0, 0,
+        (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+    sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
   }else{
-    distinct = -1;
+    distinct = addrDistinctIndex = -1;
   }
 
   /* Aggregate and non-aggregate queries are handled differently */
   if( !isAgg && pGroupBy==0 ){
-    /* This case is for non-aggregate queries
-    ** Begin the database scan
-    */
-    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, 0, 0);
+    ExprList *pDist = (isDistinct ? p->pEList : 0);
+
+    /* Begin the database scan. */
+    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, pDist, 0,0);
     if( pWInfo==0 ) goto select_end;
+    if( pWInfo->nRowOut < p->nSelectRow ) p->nSelectRow = pWInfo->nRowOut;
 
     /* If sorting index that was created by a prior OP_OpenEphemeral 
     ** instruction ended up not being needed, then change the OP_OpenEphemeral
     ** into an OP_Noop.
     */
     if( addrSortIndex>=0 && pOrderBy==0 ){
-      sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
+      sqlite3VdbeChangeToNoop(v, addrSortIndex);
       p->addrOpenEphm[2] = -1;
     }
 
-    /* Use the standard inner loop
-    */
-    assert(!isDistinct);
-    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, pDest,
+    if( pWInfo->eDistinct ){
+      VdbeOp *pOp;                /* No longer required OpenEphemeral instr. */
+     
+      assert( addrDistinctIndex>=0 );
+      pOp = sqlite3VdbeGetOp(v, addrDistinctIndex);
+
+      assert( isDistinct );
+      assert( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED 
+           || pWInfo->eDistinct==WHERE_DISTINCT_UNIQUE 
+      );
+      distinct = -1;
+      if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED ){
+        int iJump;
+        int iExpr;
+        int iFlag = ++pParse->nMem;
+        int iBase = pParse->nMem+1;
+        int iBase2 = iBase + pEList->nExpr;
+        pParse->nMem += (pEList->nExpr*2);
+
+        /* Change the OP_OpenEphemeral coded earlier to an OP_Integer. The
+        ** OP_Integer initializes the "first row" flag.  */
+        pOp->opcode = OP_Integer;
+        pOp->p1 = 1;
+        pOp->p2 = iFlag;
+
+        sqlite3ExprCodeExprList(pParse, pEList, iBase, 1);
+        iJump = sqlite3VdbeCurrentAddr(v) + 1 + pEList->nExpr + 1 + 1;
+        sqlite3VdbeAddOp2(v, OP_If, iFlag, iJump-1);
+        for(iExpr=0; iExpr<pEList->nExpr; iExpr++){
+          CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[iExpr].pExpr);
+          sqlite3VdbeAddOp3(v, OP_Ne, iBase+iExpr, iJump, iBase2+iExpr);
+          sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
+          sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+        }
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iContinue);
+
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, iFlag);
+        assert( sqlite3VdbeCurrentAddr(v)==iJump );
+        sqlite3VdbeAddOp3(v, OP_Move, iBase, iBase2, pEList->nExpr);
+      }else{
+        pOp->opcode = OP_Noop;
+      }
+    }
+
+    /* Use the standard inner loop. */
+    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, pDest,
                     pWInfo->iContinue, pWInfo->iBreak);
 
     /* End the database scan loop.
@@ -76125,6 +97671,8 @@ SQLITE_PRIVATE int sqlite3Select(
     int iAbortFlag;     /* Mem address which causes query abort if positive */
     int groupBySort;    /* Rows come from source in GROUP BY order */
     int addrEnd;        /* End of processing for this SELECT */
+    int sortPTab = 0;   /* Pseudotable used to decode sorting results */
+    int sortOut = 0;    /* Output register from the sorter */
 
     /* Remove any and all aliases between the result set and the
     ** GROUP BY clause.
@@ -76139,6 +97687,9 @@ SQLITE_PRIVATE int sqlite3Select(
       for(k=pGroupBy->nExpr, pItem=pGroupBy->a; k>0; k--, pItem++){
         pItem->iAlias = 0;
       }
+      if( p->nSelectRow>(double)100 ) p->nSelectRow = (double)100;
+    }else{
+      p->nSelectRow = (double)1;
     }
 
  
@@ -76162,7 +97713,10 @@ SQLITE_PRIVATE int sqlite3Select(
     }
     sAggInfo.nAccumulator = sAggInfo.nColumn;
     for(i=0; i<sAggInfo.nFunc; i++){
-      sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList);
+      assert( !ExprHasProperty(sAggInfo.aFunc[i].pExpr, EP_xIsSelect) );
+      sNC.ncFlags |= NC_InAggFunc;
+      sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->x.pList);
+      sNC.ncFlags &= ~NC_InAggFunc;
     }
     if( db->mallocFailed ) goto select_end;
 
@@ -76182,12 +97736,12 @@ SQLITE_PRIVATE int sqlite3Select(
 
       /* If there is a GROUP BY clause we might need a sorting index to
       ** implement it.  Allocate that sorting index now.  If it turns out
-      ** that we do not need it after all, the OpenEphemeral instruction
+      ** that we do not need it after all, the OP_SorterOpen instruction
       ** will be converted into a Noop.  
       */
       sAggInfo.sortingIdx = pParse->nTab++;
       pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
-      addrSortingIdx = sqlite3VdbeAddOp4(v, OP_OpenEphemeral, 
+      addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen, 
           sAggInfo.sortingIdx, sAggInfo.nSortingColumn, 
           0, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
 
@@ -76207,6 +97761,7 @@ SQLITE_PRIVATE int sqlite3Select(
       VdbeComment((v, "clear abort flag"));
       sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
       VdbeComment((v, "indicate accumulator empty"));
+      sqlite3VdbeAddOp3(v, OP_Null, 0, iAMem, iAMem+pGroupBy->nExpr-1);
 
       /* Begin a loop that will extract all source rows in GROUP BY order.
       ** This might involve two separate loops with an OP_Sort in between, or
@@ -76214,7 +97769,7 @@ SQLITE_PRIVATE int sqlite3Select(
       ** in the right order to begin with.
       */
       sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
-      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0, 0);
+      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0, 0, 0);
       if( pWInfo==0 ) goto select_end;
       if( pGroupBy==0 ){
         /* The optimizer is able to deliver rows in group by order so
@@ -76234,6 +97789,9 @@ SQLITE_PRIVATE int sqlite3Select(
         int nCol;
         int nGroupBy;
 
+        explainTempTable(pParse, 
+            isDistinct && !(p->selFlags&SF_Distinct)?"DISTINCT":"GROUP BY");
+
         groupBySort = 1;
         nGroupBy = pGroupBy->nExpr;
         nCol = nGroupBy + 1;
@@ -76245,6 +97803,7 @@ SQLITE_PRIVATE int sqlite3Select(
           }
         }
         regBase = sqlite3GetTempRange(pParse, nCol);
+        sqlite3ExprCacheClear(pParse);
         sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0);
         sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx,regBase+nGroupBy);
         j = nGroupBy+1;
@@ -76264,13 +97823,17 @@ SQLITE_PRIVATE int sqlite3Select(
         }
         regRecord = sqlite3GetTempReg(pParse);
         sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
-        sqlite3VdbeAddOp2(v, OP_IdxInsert, sAggInfo.sortingIdx, regRecord);
+        sqlite3VdbeAddOp2(v, OP_SorterInsert, sAggInfo.sortingIdx, regRecord);
         sqlite3ReleaseTempReg(pParse, regRecord);
         sqlite3ReleaseTempRange(pParse, regBase, nCol);
         sqlite3WhereEnd(pWInfo);
-        sqlite3VdbeAddOp2(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
+        sAggInfo.sortingIdxPTab = sortPTab = pParse->nTab++;
+        sortOut = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp3(v, OP_OpenPseudo, sortPTab, sortOut, nCol);
+        sqlite3VdbeAddOp2(v, OP_SorterSort, sAggInfo.sortingIdx, addrEnd);
         VdbeComment((v, "GROUP BY sort"));
         sAggInfo.useSortingIdx = 1;
+        sqlite3ExprCacheClear(pParse);
       }
 
       /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
@@ -76279,9 +97842,14 @@ SQLITE_PRIVATE int sqlite3Select(
       ** from the previous row currently stored in a0, a1, a2...
       */
       addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
+      sqlite3ExprCacheClear(pParse);
+      if( groupBySort ){
+        sqlite3VdbeAddOp2(v, OP_SorterData, sAggInfo.sortingIdx, sortOut);
+      }
       for(j=0; j<pGroupBy->nExpr; j++){
         if( groupBySort ){
-          sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
+          sqlite3VdbeAddOp3(v, OP_Column, sortPTab, j, iBMem+j);
+          if( j==0 ) sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
         }else{
           sAggInfo.directMode = 1;
           sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
@@ -76320,10 +97888,10 @@ SQLITE_PRIVATE int sqlite3Select(
       /* End of the loop
       */
       if( groupBySort ){
-        sqlite3VdbeAddOp2(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
+        sqlite3VdbeAddOp2(v, OP_SorterNext, sAggInfo.sortingIdx, addrTopOfLoop);
       }else{
         sqlite3WhereEnd(pWInfo);
-        sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
+        sqlite3VdbeChangeToNoop(v, addrSortingIdx);
       }
 
       /* Output the final row of result
@@ -76352,9 +97920,7 @@ SQLITE_PRIVATE int sqlite3Select(
       VdbeComment((v, "Groupby result generator entry point"));
       sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
       finalizeAggFunctions(pParse, &sAggInfo);
-      if( pHaving ){
-        sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
-      }
+      sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
       selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
                       distinct, pDest,
                       addrOutputRow+1, addrSetAbort);
@@ -76367,80 +97933,145 @@ SQLITE_PRIVATE int sqlite3Select(
       resetAccumulator(pParse, &sAggInfo);
       sqlite3VdbeAddOp1(v, OP_Return, regReset);
      
-    } /* endif pGroupBy */
+    } /* endif pGroupBy.  Begin aggregate queries without GROUP BY: */
     else {
-      ExprList *pMinMax = 0;
       ExprList *pDel = 0;
-      u8 flag;
+#ifndef SQLITE_OMIT_BTREECOUNT
+      Table *pTab;
+      if( (pTab = isSimpleCount(p, &sAggInfo))!=0 ){
+        /* If isSimpleCount() returns a pointer to a Table structure, then
+        ** the SQL statement is of the form:
+        **
+        **   SELECT count(*) FROM <tbl>
+        **
+        ** where the Table structure returned represents table <tbl>.
+        **
+        ** This statement is so common that it is optimized specially. The
+        ** OP_Count instruction is executed either on the intkey table that
+        ** contains the data for table <tbl> or on one of its indexes. It
+        ** is better to execute the op on an index, as indexes are almost
+        ** always spread across less pages than their corresponding tables.
+        */
+        const int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+        const int iCsr = pParse->nTab++;     /* Cursor to scan b-tree */
+        Index *pIdx;                         /* Iterator variable */
+        KeyInfo *pKeyInfo = 0;               /* Keyinfo for scanned index */
+        Index *pBest = 0;                    /* Best index found so far */
+        int iRoot = pTab->tnum;              /* Root page of scanned b-tree */
 
-      /* Check if the query is of one of the following forms:
-      **
-      **   SELECT min(x) FROM ...
-      **   SELECT max(x) FROM ...
-      **
-      ** If it is, then ask the code in where.c to attempt to sort results
-      ** as if there was an "ORDER ON x" or "ORDER ON x DESC" clause. 
-      ** If where.c is able to produce results sorted in this order, then
-      ** add vdbe code to break out of the processing loop after the 
-      ** first iteration (since the first iteration of the loop is 
-      ** guaranteed to operate on the row with the minimum or maximum 
-      ** value of x, the only row required).
-      **
-      ** A special flag must be passed to sqlite3WhereBegin() to slightly
-      ** modify behaviour as follows:
-      **
-      **   + If the query is a "SELECT min(x)", then the loop coded by
-      **     where.c should not iterate over any values with a NULL value
-      **     for x.
-      **
-      **   + The optimizer code in where.c (the thing that decides which
-      **     index or indices to use) should place a different priority on 
-      **     satisfying the 'ORDER BY' clause than it does in other cases.
-      **     Refer to code and comments in where.c for details.
-      */
-      flag = minMaxQuery(p);
-      if( flag ){
-        pDel = pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->pList);
-        if( pMinMax && !db->mallocFailed ){
-          pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN ?1:0;
-          pMinMax->a[0].pExpr->op = TK_COLUMN;
+        sqlite3CodeVerifySchema(pParse, iDb);
+        sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+
+        /* Search for the index that has the least amount of columns. If
+        ** there is such an index, and it has less columns than the table
+        ** does, then we can assume that it consumes less space on disk and
+        ** will therefore be cheaper to scan to determine the query result.
+        ** In this case set iRoot to the root page number of the index b-tree
+        ** and pKeyInfo to the KeyInfo structure required to navigate the
+        ** index.
+        **
+        ** (2011-04-15) Do not do a full scan of an unordered index.
+        **
+        ** In practice the KeyInfo structure will not be used. It is only 
+        ** passed to keep OP_OpenRead happy.
+        */
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          if( pIdx->bUnordered==0 && (!pBest || pIdx->nColumn<pBest->nColumn) ){
+            pBest = pIdx;
+          }
         }
+        if( pBest && pBest->nColumn<pTab->nCol ){
+          iRoot = pBest->tnum;
+          pKeyInfo = sqlite3IndexKeyinfo(pParse, pBest);
+        }
+
+        /* Open a read-only cursor, execute the OP_Count, close the cursor. */
+        sqlite3VdbeAddOp3(v, OP_OpenRead, iCsr, iRoot, iDb);
+        if( pKeyInfo ){
+          sqlite3VdbeChangeP4(v, -1, (char *)pKeyInfo, P4_KEYINFO_HANDOFF);
+        }
+        sqlite3VdbeAddOp2(v, OP_Count, iCsr, sAggInfo.aFunc[0].iMem);
+        sqlite3VdbeAddOp1(v, OP_Close, iCsr);
+        explainSimpleCount(pParse, pTab, pBest);
+      }else
+#endif /* SQLITE_OMIT_BTREECOUNT */
+      {
+        /* Check if the query is of one of the following forms:
+        **
+        **   SELECT min(x) FROM ...
+        **   SELECT max(x) FROM ...
+        **
+        ** If it is, then ask the code in where.c to attempt to sort results
+        ** as if there was an "ORDER ON x" or "ORDER ON x DESC" clause. 
+        ** If where.c is able to produce results sorted in this order, then
+        ** add vdbe code to break out of the processing loop after the 
+        ** first iteration (since the first iteration of the loop is 
+        ** guaranteed to operate on the row with the minimum or maximum 
+        ** value of x, the only row required).
+        **
+        ** A special flag must be passed to sqlite3WhereBegin() to slightly
+        ** modify behaviour as follows:
+        **
+        **   + If the query is a "SELECT min(x)", then the loop coded by
+        **     where.c should not iterate over any values with a NULL value
+        **     for x.
+        **
+        **   + The optimizer code in where.c (the thing that decides which
+        **     index or indices to use) should place a different priority on 
+        **     satisfying the 'ORDER BY' clause than it does in other cases.
+        **     Refer to code and comments in where.c for details.
+        */
+        ExprList *pMinMax = 0;
+        u8 flag = minMaxQuery(p);
+        if( flag ){
+          assert( !ExprHasProperty(p->pEList->a[0].pExpr, EP_xIsSelect) );
+          pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->x.pList,0);
+          pDel = pMinMax;
+          if( pMinMax && !db->mallocFailed ){
+            pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN ?1:0;
+            pMinMax->a[0].pExpr->op = TK_COLUMN;
+          }
+        }
+  
+        /* This case runs if the aggregate has no GROUP BY clause.  The
+        ** processing is much simpler since there is only a single row
+        ** of output.
+        */
+        resetAccumulator(pParse, &sAggInfo);
+        pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax,0,flag,0);
+        if( pWInfo==0 ){
+          sqlite3ExprListDelete(db, pDel);
+          goto select_end;
+        }
+        updateAccumulator(pParse, &sAggInfo);
+        if( !pMinMax && flag ){
+          sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
+          VdbeComment((v, "%s() by index",
+                (flag==WHERE_ORDERBY_MIN?"min":"max")));
+        }
+        sqlite3WhereEnd(pWInfo);
+        finalizeAggFunctions(pParse, &sAggInfo);
       }
 
-      /* This case runs if the aggregate has no GROUP BY clause.  The
-      ** processing is much simpler since there is only a single row
-      ** of output.
-      */
-      resetAccumulator(pParse, &sAggInfo);
-      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax, flag, 0);
-      if( pWInfo==0 ){
-        sqlite3ExprListDelete(db, pDel);
-        goto select_end;
-      }
-      updateAccumulator(pParse, &sAggInfo);
-      if( !pMinMax && flag ){
-        sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
-        VdbeComment((v, "%s() by index",(flag==WHERE_ORDERBY_MIN?"min":"max")));
-      }
-      sqlite3WhereEnd(pWInfo);
-      finalizeAggFunctions(pParse, &sAggInfo);
       pOrderBy = 0;
-      if( pHaving ){
-        sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
-      }
+      sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
       selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, 
                       pDest, addrEnd, addrEnd);
-
       sqlite3ExprListDelete(db, pDel);
     }
     sqlite3VdbeResolveLabel(v, addrEnd);
     
   } /* endif aggregate query */
 
+  if( distinct>=0 ){
+    explainTempTable(pParse, "DISTINCT");
+  }
+
   /* If there is an ORDER BY clause, then we need to sort the results
   ** and send them to the callback one by one.
   */
   if( pOrderBy ){
+    explainTempTable(pParse, "ORDER BY");
     generateSortTail(pParse, p, v, pEList->nExpr, pDest);
   }
 
@@ -76457,6 +98088,7 @@ SQLITE_PRIVATE int sqlite3Select(
   ** successful coding of the SELECT.
   */
 select_end:
+  explainSetInteger(pParse->iSelectId, iRestoreSelectId);
 
   /* Identify column names if results of the SELECT are to be output.
   */
@@ -76469,101 +98101,101 @@ select_end:
   return rc;
 }
 
-#if defined(SQLITE_DEBUG)
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
 /*
-*******************************************************************************
-** The following code is used for testing and debugging only.  The code
-** that follows does not appear in normal builds.
-**
-** These routines are used to print out the content of all or part of a 
-** parse structures such as Select or Expr.  Such printouts are useful
-** for helping to understand what is happening inside the code generator
-** during the execution of complex SELECT statements.
-**
-** These routine are not called anywhere from within the normal
-** code base.  Then are intended to be called from within the debugger
-** or from temporary "printf" statements inserted for debugging.
+** Generate a human-readable description of a the Select object.
 */
-SQLITE_PRIVATE void sqlite3PrintExpr(Expr *p){
-  if( p->token.z && p->token.n>0 ){
-    sqlite3DebugPrintf("(%.*s", p->token.n, p->token.z);
-  }else{
-    sqlite3DebugPrintf("(%d", p->op);
-  }
-  if( p->pLeft ){
-    sqlite3DebugPrintf(" ");
-    sqlite3PrintExpr(p->pLeft);
-  }
-  if( p->pRight ){
-    sqlite3DebugPrintf(" ");
-    sqlite3PrintExpr(p->pRight);
-  }
-  sqlite3DebugPrintf(")");
-}
-SQLITE_PRIVATE void sqlite3PrintExprList(ExprList *pList){
-  int i;
-  for(i=0; i<pList->nExpr; i++){
-    sqlite3PrintExpr(pList->a[i].pExpr);
-    if( i<pList->nExpr-1 ){
-      sqlite3DebugPrintf(", ");
+static void explainOneSelect(Vdbe *pVdbe, Select *p){
+  sqlite3ExplainPrintf(pVdbe, "SELECT ");
+  if( p->selFlags & (SF_Distinct|SF_Aggregate) ){
+    if( p->selFlags & SF_Distinct ){
+      sqlite3ExplainPrintf(pVdbe, "DISTINCT ");
     }
+    if( p->selFlags & SF_Aggregate ){
+      sqlite3ExplainPrintf(pVdbe, "agg_flag ");
+    }
+    sqlite3ExplainNL(pVdbe);
+    sqlite3ExplainPrintf(pVdbe, "   ");
   }
-}
-SQLITE_PRIVATE void sqlite3PrintSelect(Select *p, int indent){
-  sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
-  sqlite3PrintExprList(p->pEList);
-  sqlite3DebugPrintf("\n");
-  if( p->pSrc ){
-    char *zPrefix;
+  sqlite3ExplainExprList(pVdbe, p->pEList);
+  sqlite3ExplainNL(pVdbe);
+  if( p->pSrc && p->pSrc->nSrc ){
     int i;
-    zPrefix = "FROM";
+    sqlite3ExplainPrintf(pVdbe, "FROM ");
+    sqlite3ExplainPush(pVdbe);
     for(i=0; i<p->pSrc->nSrc; i++){
       struct SrcList_item *pItem = &p->pSrc->a[i];
-      sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
-      zPrefix = "";
+      sqlite3ExplainPrintf(pVdbe, "{%d,*} = ", pItem->iCursor);
       if( pItem->pSelect ){
-        sqlite3DebugPrintf("(\n");
-        sqlite3PrintSelect(pItem->pSelect, indent+10);
-        sqlite3DebugPrintf("%*s)", indent+8, "");
+        sqlite3ExplainSelect(pVdbe, pItem->pSelect);
+        if( pItem->pTab ){
+          sqlite3ExplainPrintf(pVdbe, " (tabname=%s)", pItem->pTab->zName);
+        }
       }else if( pItem->zName ){
-        sqlite3DebugPrintf("%s", pItem->zName);
-      }
-      if( pItem->pTab ){
-        sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
+        sqlite3ExplainPrintf(pVdbe, "%s", pItem->zName);
       }
       if( pItem->zAlias ){
-        sqlite3DebugPrintf(" AS %s", pItem->zAlias);
+        sqlite3ExplainPrintf(pVdbe, " (AS %s)", pItem->zAlias);
       }
-      if( i<p->pSrc->nSrc-1 ){
-        sqlite3DebugPrintf(",");
+      if( pItem->jointype & JT_LEFT ){
+        sqlite3ExplainPrintf(pVdbe, " LEFT-JOIN");
       }
-      sqlite3DebugPrintf("\n");
+      sqlite3ExplainNL(pVdbe);
     }
+    sqlite3ExplainPop(pVdbe);
   }
   if( p->pWhere ){
-    sqlite3DebugPrintf("%*s WHERE ", indent, "");
-    sqlite3PrintExpr(p->pWhere);
-    sqlite3DebugPrintf("\n");
+    sqlite3ExplainPrintf(pVdbe, "WHERE ");
+    sqlite3ExplainExpr(pVdbe, p->pWhere);
+    sqlite3ExplainNL(pVdbe);
   }
   if( p->pGroupBy ){
-    sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
-    sqlite3PrintExprList(p->pGroupBy);
-    sqlite3DebugPrintf("\n");
+    sqlite3ExplainPrintf(pVdbe, "GROUPBY ");
+    sqlite3ExplainExprList(pVdbe, p->pGroupBy);
+    sqlite3ExplainNL(pVdbe);
   }
   if( p->pHaving ){
-    sqlite3DebugPrintf("%*s HAVING ", indent, "");
-    sqlite3PrintExpr(p->pHaving);
-    sqlite3DebugPrintf("\n");
+    sqlite3ExplainPrintf(pVdbe, "HAVING ");
+    sqlite3ExplainExpr(pVdbe, p->pHaving);
+    sqlite3ExplainNL(pVdbe);
   }
   if( p->pOrderBy ){
-    sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
-    sqlite3PrintExprList(p->pOrderBy);
-    sqlite3DebugPrintf("\n");
+    sqlite3ExplainPrintf(pVdbe, "ORDERBY ");
+    sqlite3ExplainExprList(pVdbe, p->pOrderBy);
+    sqlite3ExplainNL(pVdbe);
+  }
+  if( p->pLimit ){
+    sqlite3ExplainPrintf(pVdbe, "LIMIT ");
+    sqlite3ExplainExpr(pVdbe, p->pLimit);
+    sqlite3ExplainNL(pVdbe);
+  }
+  if( p->pOffset ){
+    sqlite3ExplainPrintf(pVdbe, "OFFSET ");
+    sqlite3ExplainExpr(pVdbe, p->pOffset);
+    sqlite3ExplainNL(pVdbe);
   }
 }
+SQLITE_PRIVATE void sqlite3ExplainSelect(Vdbe *pVdbe, Select *p){
+  if( p==0 ){
+    sqlite3ExplainPrintf(pVdbe, "(null-select)");
+    return;
+  }
+  while( p->pPrior ) p = p->pPrior;
+  sqlite3ExplainPush(pVdbe);
+  while( p ){
+    explainOneSelect(pVdbe, p);
+    p = p->pNext;
+    if( p==0 ) break;
+    sqlite3ExplainNL(pVdbe);
+    sqlite3ExplainPrintf(pVdbe, "%s\n", selectOpName(p->op));
+  }
+  sqlite3ExplainPrintf(pVdbe, "END");
+  sqlite3ExplainPop(pVdbe);
+}
+
 /* End of the structure debug printing code
 *****************************************************************************/
-#endif /* defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
+#endif /* defined(SQLITE_ENABLE_TREE_EXPLAIN) */
 
 /************** End of select.c **********************************************/
 /************** Begin file table.c *******************************************/
@@ -76584,9 +98216,9 @@ SQLITE_PRIVATE void sqlite3PrintSelect(Select *p, int indent){
 **
 ** These routines are in a separate files so that they will not be linked
 ** if they are not used.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/* #include <stdlib.h> */
+/* #include <string.h> */
 
 #ifndef SQLITE_OMIT_GET_TABLE
 
@@ -76595,14 +98227,13 @@ SQLITE_PRIVATE void sqlite3PrintSelect(Select *p, int indent){
 ** to the callback function is uses to build the result.
 */
 typedef struct TabResult {
-  char **azResult;
-  char *zErrMsg;
-  int nResult;
-  int nAlloc;
-  int nRow;
-  int nColumn;
-  int nData;
-  int rc;
+  char **azResult;   /* Accumulated output */
+  char *zErrMsg;     /* Error message text, if an error occurs */
+  int nAlloc;        /* Slots allocated for azResult[] */
+  int nRow;          /* Number of rows in the result */
+  int nColumn;       /* Number of columns in the result */
+  int nData;         /* Slots used in azResult[].  (nRow+1)*nColumn */
+  int rc;            /* Return code from sqlite3_exec() */
 } TabResult;
 
 /*
@@ -76611,10 +98242,10 @@ typedef struct TabResult {
 ** memory as necessary.
 */
 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
-  TabResult *p = (TabResult*)pArg;
-  int need;
-  int i;
-  char *z;
+  TabResult *p = (TabResult*)pArg;  /* Result accumulator */
+  int need;                         /* Slots needed in p->azResult[] */
+  int i;                            /* Loop counter */
+  char *z;                          /* A single column of result */
 
   /* Make sure there is enough space in p->azResult to hold everything
   ** we need to remember from this invocation of the callback.
@@ -76624,9 +98255,9 @@ static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
   }else{
     need = nCol;
   }
-  if( p->nData + need >= p->nAlloc ){
+  if( p->nData + need > p->nAlloc ){
     char **azNew;
-    p->nAlloc = p->nAlloc*2 + need + 1;
+    p->nAlloc = p->nAlloc*2 + need;
     azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc );
     if( azNew==0 ) goto malloc_failed;
     p->azResult = azNew;
@@ -76698,8 +98329,8 @@ SQLITE_API int sqlite3_get_table(
   *pazResult = 0;
   if( pnColumn ) *pnColumn = 0;
   if( pnRow ) *pnRow = 0;
+  if( pzErrMsg ) *pzErrMsg = 0;
   res.zErrMsg = 0;
-  res.nResult = 0;
   res.nRow = 0;
   res.nColumn = 0;
   res.nData = 1;
@@ -76733,13 +98364,12 @@ SQLITE_API int sqlite3_get_table(
   }
   if( res.nAlloc>res.nData ){
     char **azNew;
-    azNew = sqlite3_realloc( res.azResult, sizeof(char*)*(res.nData+1) );
+    azNew = sqlite3_realloc( res.azResult, sizeof(char*)*res.nData );
     if( azNew==0 ){
       sqlite3_free_table(&res.azResult[1]);
       db->errCode = SQLITE_NOMEM;
       return SQLITE_NOMEM;
     }
-    res.nAlloc = res.nData+1;
     res.azResult = azNew;
   }
   *pazResult = &res.azResult[1];
@@ -76778,9 +98408,7 @@ SQLITE_API void sqlite3_free_table(
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-**
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+** This file contains the implementation for TRIGGERs
 */
 
 #ifndef SQLITE_OMIT_TRIGGER
@@ -76792,7 +98420,6 @@ SQLITE_PRIVATE void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerS
     TriggerStep * pTmp = pTriggerStep;
     pTriggerStep = pTriggerStep->pNext;
 
-    if( pTmp->target.dyn ) sqlite3DbFree(db, (char*)pTmp->target.z);
     sqlite3ExprDelete(db, pTmp->pWhere);
     sqlite3ExprListDelete(db, pTmp->pExprList);
     sqlite3SelectDelete(db, pTmp->pSelect);
@@ -76802,6 +98429,45 @@ SQLITE_PRIVATE void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerS
   }
 }
 
+/*
+** Given table pTab, return a list of all the triggers attached to 
+** the table. The list is connected by Trigger.pNext pointers.
+**
+** All of the triggers on pTab that are in the same database as pTab
+** are already attached to pTab->pTrigger.  But there might be additional
+** triggers on pTab in the TEMP schema.  This routine prepends all
+** TEMP triggers on pTab to the beginning of the pTab->pTrigger list
+** and returns the combined list.
+**
+** To state it another way:  This routine returns a list of all triggers
+** that fire off of pTab.  The list will include any TEMP triggers on
+** pTab as well as the triggers lised in pTab->pTrigger.
+*/
+SQLITE_PRIVATE Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
+  Schema * const pTmpSchema = pParse->db->aDb[1].pSchema;
+  Trigger *pList = 0;                  /* List of triggers to return */
+
+  if( pParse->disableTriggers ){
+    return 0;
+  }
+
+  if( pTmpSchema!=pTab->pSchema ){
+    HashElem *p;
+    assert( sqlite3SchemaMutexHeld(pParse->db, 0, pTmpSchema) );
+    for(p=sqliteHashFirst(&pTmpSchema->trigHash); p; p=sqliteHashNext(p)){
+      Trigger *pTrig = (Trigger *)sqliteHashData(p);
+      if( pTrig->pTabSchema==pTab->pSchema
+       && 0==sqlite3StrICmp(pTrig->table, pTab->zName) 
+      ){
+        pTrig->pNext = (pList ? pList : pTab->pTrigger);
+        pList = pTrig;
+      }
+    }
+  }
+
+  return (pList ? pList : pTab->pTrigger);
+}
+
 /*
 ** This is called by the parser when it sees a CREATE TRIGGER statement
 ** up to the point of the BEGIN before the trigger actions.  A Trigger
@@ -76822,14 +98488,14 @@ SQLITE_PRIVATE void sqlite3BeginTrigger(
   int isTemp,         /* True if the TEMPORARY keyword is present */
   int noErr           /* Suppress errors if the trigger already exists */
 ){
-  Trigger *pTrigger = 0;
-  Table *pTab;
+  Trigger *pTrigger = 0;  /* The new trigger */
+  Table *pTab;            /* Table that the trigger fires off of */
   char *zName = 0;        /* Name of the trigger */
-  sqlite3 *db = pParse->db;
+  sqlite3 *db = pParse->db;  /* The database connection */
   int iDb;                /* The database to store the trigger in */
   Token *pName;           /* The unqualified db name */
-  DbFixer sFix;
-  int iTabDb;
+  DbFixer sFix;           /* State vector for the DB fixer */
+  int iTabDb;             /* Index of the database holding pTab */
 
   assert( pName1!=0 );   /* pName1->z might be NULL, but not pName1 itself */
   assert( pName2!=0 );
@@ -76844,23 +98510,37 @@ SQLITE_PRIVATE void sqlite3BeginTrigger(
     iDb = 1;
     pName = pName1;
   }else{
-    /* Figure out the db that the the trigger will be created in */
+    /* Figure out the db that the trigger will be created in */
     iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
     if( iDb<0 ){
       goto trigger_cleanup;
     }
   }
+  if( !pTableName || db->mallocFailed ){
+    goto trigger_cleanup;
+  }
+
+  /* A long-standing parser bug is that this syntax was allowed:
+  **
+  **    CREATE TRIGGER attached.demo AFTER INSERT ON attached.tab ....
+  **                                                 ^^^^^^^^
+  **
+  ** To maintain backwards compatibility, ignore the database
+  ** name on pTableName if we are reparsing our of SQLITE_MASTER.
+  */
+  if( db->init.busy && iDb!=1 ){
+    sqlite3DbFree(db, pTableName->a[0].zDatabase);
+    pTableName->a[0].zDatabase = 0;
+  }
 
   /* If the trigger name was unqualified, and the table is a temp table,
   ** then set iDb to 1 to create the trigger in the temporary database.
   ** If sqlite3SrcListLookup() returns 0, indicating the table does not
   ** exist, the error is caught by the block below.
   */
-  if( !pTableName || db->mallocFailed ){
-    goto trigger_cleanup;
-  }
   pTab = sqlite3SrcListLookup(pParse, pTableName);
-  if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
+  if( db->init.busy==0 && pName2->n==0 && pTab
+        && pTab->pSchema==db->aDb[1].pSchema ){
     iDb = 1;
   }
 
@@ -76874,6 +98554,17 @@ SQLITE_PRIVATE void sqlite3BeginTrigger(
   pTab = sqlite3SrcListLookup(pParse, pTableName);
   if( !pTab ){
     /* The table does not exist. */
+    if( db->init.iDb==1 ){
+      /* Ticket #3810.
+      ** Normally, whenever a table is dropped, all associated triggers are
+      ** dropped too.  But if a TEMP trigger is created on a non-TEMP table
+      ** and the table is dropped by a different database connection, the
+      ** trigger is not visible to the database connection that does the
+      ** drop so the trigger cannot be dropped.  This results in an
+      ** "orphaned trigger" - a trigger whose associated table is missing.
+      */
+      db->init.orphanTrigger = 1;
+    }
     goto trigger_cleanup;
   }
   if( IsVirtual(pTab) ){
@@ -76887,10 +98578,14 @@ SQLITE_PRIVATE void sqlite3BeginTrigger(
   if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
     goto trigger_cleanup;
   }
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
   if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash),
                       zName, sqlite3Strlen30(zName)) ){
     if( !noErr ){
       sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
+    }else{
+      assert( !db->init.busy );
+      sqlite3CodeVerifySchema(pParse, iDb);
     }
     goto trigger_cleanup;
   }
@@ -76944,16 +98639,15 @@ SQLITE_PRIVATE void sqlite3BeginTrigger(
   /* Build the Trigger object */
   pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
   if( pTrigger==0 ) goto trigger_cleanup;
-  pTrigger->name = zName;
+  pTrigger->zName = zName;
   zName = 0;
   pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
   pTrigger->pSchema = db->aDb[iDb].pSchema;
   pTrigger->pTabSchema = pTab->pSchema;
   pTrigger->op = (u8)op;
   pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
-  pTrigger->pWhen = sqlite3ExprDup(db, pWhen);
+  pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
   pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
-  sqlite3TokenCopy(db, &pTrigger->nameToken,pName);
   assert( pParse->pNewTrigger==0 );
   pParse->pNewTrigger = pTrigger;
 
@@ -76978,26 +98672,30 @@ SQLITE_PRIVATE void sqlite3FinishTrigger(
   TriggerStep *pStepList, /* The triggered program */
   Token *pAll             /* Token that describes the complete CREATE TRIGGER */
 ){
-  Trigger *pTrig = 0;     /* The trigger whose construction is finishing up */
-  sqlite3 *db = pParse->db;  /* The database */
-  DbFixer sFix;
-  int iDb;                   /* Database containing the trigger */
+  Trigger *pTrig = pParse->pNewTrigger;   /* Trigger being finished */
+  char *zName;                            /* Name of trigger */
+  sqlite3 *db = pParse->db;               /* The database */
+  DbFixer sFix;                           /* Fixer object */
+  int iDb;                                /* Database containing the trigger */
+  Token nameToken;                        /* Trigger name for error reporting */
 
-  pTrig = pParse->pNewTrigger;
   pParse->pNewTrigger = 0;
-  if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
+  if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
+  zName = pTrig->zName;
   iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
   pTrig->step_list = pStepList;
   while( pStepList ){
     pStepList->pTrig = pTrig;
     pStepList = pStepList->pNext;
   }
-  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken) 
+  nameToken.z = pTrig->zName;
+  nameToken.n = sqlite3Strlen30(nameToken.z);
+  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken) 
           && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
     goto triggerfinish_cleanup;
   }
 
-  /* if we are not initializing, and this trigger is not on a TEMP table, 
+  /* if we are not initializing,
   ** build the sqlite_master entry
   */
   if( !db->init.busy ){
@@ -77011,32 +98709,29 @@ SQLITE_PRIVATE void sqlite3FinishTrigger(
     z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n);
     sqlite3NestedParse(pParse,
        "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
-       db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pTrig->name,
+       db->aDb[iDb].zName, SCHEMA_TABLE(iDb), zName,
        pTrig->table, z);
     sqlite3DbFree(db, z);
     sqlite3ChangeCookie(pParse, iDb);
-    sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, sqlite3MPrintf(
-        db, "type='trigger' AND name='%q'", pTrig->name), P4_DYNAMIC
-    );
+    sqlite3VdbeAddParseSchemaOp(v, iDb,
+        sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName));
   }
 
   if( db->init.busy ){
-    int n;
-    Table *pTab;
-    Trigger *pDel;
-    pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash, 
-                     pTrig->name, sqlite3Strlen30(pTrig->name), pTrig);
-    if( pDel ){
-      assert( pDel==pTrig );
+    Trigger *pLink = pTrig;
+    Hash *pHash = &db->aDb[iDb].pSchema->trigHash;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    pTrig = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), pTrig);
+    if( pTrig ){
       db->mallocFailed = 1;
-      goto triggerfinish_cleanup;
+    }else if( pLink->pSchema==pLink->pTabSchema ){
+      Table *pTab;
+      int n = sqlite3Strlen30(pLink->table);
+      pTab = sqlite3HashFind(&pLink->pTabSchema->tblHash, pLink->table, n);
+      assert( pTab!=0 );
+      pLink->pNext = pTab->pTrigger;
+      pTab->pTrigger = pLink;
     }
-    n = sqlite3Strlen30(pTrig->table) + 1;
-    pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
-    assert( pTab!=0 );
-    pTrig->pNext = pTab->pTrigger;
-    pTab->pTrigger = pTrig;
-    pTrig = 0;
   }
 
 triggerfinish_cleanup:
@@ -77045,43 +98740,6 @@ triggerfinish_cleanup:
   sqlite3DeleteTriggerStep(db, pStepList);
 }
 
-/*
-** Make a copy of all components of the given trigger step.  This has
-** the effect of copying all Expr.token.z values into memory obtained
-** from sqlite3_malloc().  As initially created, the Expr.token.z values
-** all point to the input string that was fed to the parser.  But that
-** string is ephemeral - it will go away as soon as the sqlite3_exec()
-** call that started the parser exits.  This routine makes a persistent
-** copy of all the Expr.token.z strings so that the TriggerStep structure
-** will be valid even after the sqlite3_exec() call returns.
-*/
-static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){
-  if( p->target.z ){
-    p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n);
-    p->target.dyn = 1;
-  }
-  if( p->pSelect ){
-    Select *pNew = sqlite3SelectDup(db, p->pSelect);
-    sqlite3SelectDelete(db, p->pSelect);
-    p->pSelect = pNew;
-  }
-  if( p->pWhere ){
-    Expr *pNew = sqlite3ExprDup(db, p->pWhere);
-    sqlite3ExprDelete(db, p->pWhere);
-    p->pWhere = pNew;
-  }
-  if( p->pExprList ){
-    ExprList *pNew = sqlite3ExprListDup(db, p->pExprList);
-    sqlite3ExprListDelete(db, p->pExprList);
-    p->pExprList = pNew;
-  }
-  if( p->pIdList ){
-    IdList *pNew = sqlite3IdListDup(db, p->pIdList);
-    sqlite3IdListDelete(db, p->pIdList);
-    p->pIdList = pNew;
-  }
-}
-
 /*
 ** Turn a SELECT statement (that the pSelect parameter points to) into
 ** a trigger step.  Return a pointer to a TriggerStep structure.
@@ -77095,12 +98753,33 @@ SQLITE_PRIVATE TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelec
     sqlite3SelectDelete(db, pSelect);
     return 0;
   }
-
   pTriggerStep->op = TK_SELECT;
   pTriggerStep->pSelect = pSelect;
   pTriggerStep->orconf = OE_Default;
-  sqlitePersistTriggerStep(db, pTriggerStep);
+  return pTriggerStep;
+}
 
+/*
+** Allocate space to hold a new trigger step.  The allocated space
+** holds both the TriggerStep object and the TriggerStep.target.z string.
+**
+** If an OOM error occurs, NULL is returned and db->mallocFailed is set.
+*/
+static TriggerStep *triggerStepAllocate(
+  sqlite3 *db,                /* Database connection */
+  u8 op,                      /* Trigger opcode */
+  Token *pName                /* The target name */
+){
+  TriggerStep *pTriggerStep;
+
+  pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep) + pName->n);
+  if( pTriggerStep ){
+    char *z = (char*)&pTriggerStep[1];
+    memcpy(z, pName->z, pName->n);
+    pTriggerStep->target.z = z;
+    pTriggerStep->target.n = pName->n;
+    pTriggerStep->op = op;
+  }
   return pTriggerStep;
 }
 
@@ -77117,27 +98796,24 @@ SQLITE_PRIVATE TriggerStep *sqlite3TriggerInsertStep(
   IdList *pColumn,    /* List of columns in pTableName to insert into */
   ExprList *pEList,   /* The VALUE clause: a list of values to be inserted */
   Select *pSelect,    /* A SELECT statement that supplies values */
-  int orconf          /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
+  u8 orconf           /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
 ){
   TriggerStep *pTriggerStep;
 
   assert(pEList == 0 || pSelect == 0);
   assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
 
-  pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
+  pTriggerStep = triggerStepAllocate(db, TK_INSERT, pTableName);
   if( pTriggerStep ){
-    pTriggerStep->op = TK_INSERT;
-    pTriggerStep->pSelect = pSelect;
-    pTriggerStep->target  = *pTableName;
+    pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
     pTriggerStep->pIdList = pColumn;
-    pTriggerStep->pExprList = pEList;
+    pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
     pTriggerStep->orconf = orconf;
-    sqlitePersistTriggerStep(db, pTriggerStep);
   }else{
     sqlite3IdListDelete(db, pColumn);
-    sqlite3ExprListDelete(db, pEList);
-    sqlite3SelectDelete(db, pSelect);
   }
+  sqlite3ExprListDelete(db, pEList);
+  sqlite3SelectDelete(db, pSelect);
 
   return pTriggerStep;
 }
@@ -77152,22 +98828,18 @@ SQLITE_PRIVATE TriggerStep *sqlite3TriggerUpdateStep(
   Token *pTableName,   /* Name of the table to be updated */
   ExprList *pEList,    /* The SET clause: list of column and new values */
   Expr *pWhere,        /* The WHERE clause */
-  int orconf           /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
+  u8 orconf            /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
 ){
-  TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
-  if( pTriggerStep==0 ){
-     sqlite3ExprListDelete(db, pEList);
-     sqlite3ExprDelete(db, pWhere);
-     return 0;
+  TriggerStep *pTriggerStep;
+
+  pTriggerStep = triggerStepAllocate(db, TK_UPDATE, pTableName);
+  if( pTriggerStep ){
+    pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
+    pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+    pTriggerStep->orconf = orconf;
   }
-
-  pTriggerStep->op = TK_UPDATE;
-  pTriggerStep->target  = *pTableName;
-  pTriggerStep->pExprList = pEList;
-  pTriggerStep->pWhere = pWhere;
-  pTriggerStep->orconf = orconf;
-  sqlitePersistTriggerStep(db, pTriggerStep);
-
+  sqlite3ExprListDelete(db, pEList);
+  sqlite3ExprDelete(db, pWhere);
   return pTriggerStep;
 }
 
@@ -77181,18 +98853,14 @@ SQLITE_PRIVATE TriggerStep *sqlite3TriggerDeleteStep(
   Token *pTableName,      /* The table from which rows are deleted */
   Expr *pWhere            /* The WHERE clause */
 ){
-  TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
-  if( pTriggerStep==0 ){
-    sqlite3ExprDelete(db, pWhere);
-    return 0;
+  TriggerStep *pTriggerStep;
+
+  pTriggerStep = triggerStepAllocate(db, TK_DELETE, pTableName);
+  if( pTriggerStep ){
+    pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+    pTriggerStep->orconf = OE_Default;
   }
-
-  pTriggerStep->op = TK_DELETE;
-  pTriggerStep->target  = *pTableName;
-  pTriggerStep->pWhere = pWhere;
-  pTriggerStep->orconf = OE_Default;
-  sqlitePersistTriggerStep(db, pTriggerStep);
-
+  sqlite3ExprDelete(db, pWhere);
   return pTriggerStep;
 }
 
@@ -77202,11 +98870,10 @@ SQLITE_PRIVATE TriggerStep *sqlite3TriggerDeleteStep(
 SQLITE_PRIVATE void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
   if( pTrigger==0 ) return;
   sqlite3DeleteTriggerStep(db, pTrigger->step_list);
-  sqlite3DbFree(db, pTrigger->name);
+  sqlite3DbFree(db, pTrigger->zName);
   sqlite3DbFree(db, pTrigger->table);
   sqlite3ExprDelete(db, pTrigger->pWhen);
   sqlite3IdListDelete(db, pTrigger->pColumns);
-  if( pTrigger->nameToken.dyn ) sqlite3DbFree(db, (char*)pTrigger->nameToken.z);
   sqlite3DbFree(db, pTrigger);
 }
 
@@ -77235,16 +98902,21 @@ SQLITE_PRIVATE void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr)
   zDb = pName->a[0].zDatabase;
   zName = pName->a[0].zName;
   nName = sqlite3Strlen30(zName);
+  assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
   for(i=OMIT_TEMPDB; i<db->nDb; i++){
     int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
     if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
+    assert( sqlite3SchemaMutexHeld(db, j, 0) );
     pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
     if( pTrigger ) break;
   }
   if( !pTrigger ){
     if( !noErr ){
       sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
+    }else{
+      sqlite3CodeVerifyNamedSchema(pParse, zDb);
     }
+    pParse->checkSchema = 1;
     goto drop_trigger_cleanup;
   }
   sqlite3DropTriggerPtr(pParse, pTrigger);
@@ -77258,7 +98930,7 @@ drop_trigger_cleanup:
 ** is set on.
 */
 static Table *tableOfTrigger(Trigger *pTrigger){
-  int n = sqlite3Strlen30(pTrigger->table) + 1;
+  int n = sqlite3Strlen30(pTrigger->table);
   return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
 }
 
@@ -77283,7 +98955,7 @@ SQLITE_PRIVATE void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
     const char *zDb = db->aDb[iDb].zName;
     const char *zTab = SCHEMA_TABLE(iDb);
     if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
-    if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
+    if( sqlite3AuthCheck(pParse, code, pTrigger->zName, pTable->zName, zDb) ||
       sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
       return;
     }
@@ -77310,11 +98982,14 @@ SQLITE_PRIVATE void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
     sqlite3BeginWriteOperation(pParse, 0, iDb);
     sqlite3OpenMasterTable(pParse, iDb);
     base = sqlite3VdbeAddOpList(v,  ArraySize(dropTrigger), dropTrigger);
-    sqlite3VdbeChangeP4(v, base+1, pTrigger->name, 0);
+    sqlite3VdbeChangeP4(v, base+1, pTrigger->zName, P4_TRANSIENT);
     sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC);
     sqlite3ChangeCookie(pParse, iDb);
     sqlite3VdbeAddOp2(v, OP_Close, 0, 0);
-    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->name, 0);
+    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);
+    if( pParse->nMem<3 ){
+      pParse->nMem = 3;
+    }
   }
 }
 
@@ -77323,24 +98998,17 @@ SQLITE_PRIVATE void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
 */
 SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
   Trigger *pTrigger;
-  int nName = sqlite3Strlen30(zName);
-  pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash),
-                               zName, nName, 0);
-  if( pTrigger ){
-    Table *pTable = tableOfTrigger(pTrigger);
-    assert( pTable!=0 );
-    if( pTable->pTrigger == pTrigger ){
-      pTable->pTrigger = pTrigger->pNext;
-    }else{
-      Trigger *cc = pTable->pTrigger;
-      while( cc ){ 
-        if( cc->pNext == pTrigger ){
-          cc->pNext = cc->pNext->pNext;
-          break;
-        }
-        cc = cc->pNext;
-      }
-      assert(cc);
+  Hash *pHash;
+
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pHash = &(db->aDb[iDb].pSchema->trigHash);
+  pTrigger = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), 0);
+  if( ALWAYS(pTrigger) ){
+    if( pTrigger->pSchema==pTrigger->pTabSchema ){
+      Table *pTab = tableOfTrigger(pTrigger);
+      Trigger **pp;
+      for(pp=&pTab->pTrigger; *pp!=pTrigger; pp=&((*pp)->pNext));
+      *pp = (*pp)->pNext;
     }
     sqlite3DeleteTrigger(db, pTrigger);
     db->flags |= SQLITE_InternChanges;
@@ -77356,9 +99024,9 @@ SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const ch
 ** it matches anything so always return true.  Return false only
 ** if there is no match.
 */
-static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
+static int checkColumnOverlap(IdList *pIdList, ExprList *pEList){
   int e;
-  if( !pIdList || !pEList ) return 1;
+  if( pIdList==0 || NEVER(pEList==0) ) return 1;
   for(e=0; e<pEList->nExpr; e++){
     if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
   }
@@ -77366,30 +99034,35 @@ static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
 }
 
 /*
-** Return a bit vector to indicate what kind of triggers exist for operation
-** "op" on table pTab.  If pChanges is not NULL then it is a list of columns
-** that are being updated.  Triggers only match if the ON clause of the
-** trigger definition overlaps the set of columns being updated.
-**
-** The returned bit vector is some combination of TRIGGER_BEFORE and
-** TRIGGER_AFTER.
+** Return a list of all triggers on table pTab if there exists at least
+** one trigger that must be fired when an operation of type 'op' is 
+** performed on the table, and, if that operation is an UPDATE, if at
+** least one of the columns in pChanges is being modified.
 */
-SQLITE_PRIVATE int sqlite3TriggersExist(
+SQLITE_PRIVATE Trigger *sqlite3TriggersExist(
+  Parse *pParse,          /* Parse context */
   Table *pTab,            /* The table the contains the triggers */
   int op,                 /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
-  ExprList *pChanges      /* Columns that change in an UPDATE statement */
+  ExprList *pChanges,     /* Columns that change in an UPDATE statement */
+  int *pMask              /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
 ){
-  Trigger *pTrigger;
   int mask = 0;
+  Trigger *pList = 0;
+  Trigger *p;
 
-  pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger;
-  while( pTrigger ){
-    if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
-      mask |= pTrigger->tr_tm;
-    }
-    pTrigger = pTrigger->pNext;
+  if( (pParse->db->flags & SQLITE_EnableTrigger)!=0 ){
+    pList = sqlite3TriggerList(pParse, pTab);
   }
-  return mask;
+  assert( pList==0 || IsVirtual(pTab)==0 );
+  for(p=pList; p; p=p->pNext){
+    if( p->op==op && checkColumnOverlap(p->pColumns, pChanges) ){
+      mask |= p->tr_tm;
+    }
+  }
+  if( pMask ){
+    *pMask = mask;
+  }
+  return (mask ? pList : 0);
 }
 
 /*
@@ -77406,221 +99079,447 @@ static SrcList *targetSrcList(
   Parse *pParse,       /* The parsing context */
   TriggerStep *pStep   /* The trigger containing the target token */
 ){
-  Token sDb;           /* Dummy database name token */
   int iDb;             /* Index of the database to use */
   SrcList *pSrc;       /* SrcList to be returned */
 
-  iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
-  if( iDb==0 || iDb>=2 ){
-    assert( iDb<pParse->db->nDb );
-    sDb.z = (u8*)pParse->db->aDb[iDb].zName;
-    sDb.n = sqlite3Strlen30((char*)sDb.z);
-    pSrc = sqlite3SrcListAppend(pParse->db, 0, &sDb, &pStep->target);
-  } else {
-    pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
+  pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
+  if( pSrc ){
+    assert( pSrc->nSrc>0 );
+    assert( pSrc->a!=0 );
+    iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
+    if( iDb==0 || iDb>=2 ){
+      sqlite3 *db = pParse->db;
+      assert( iDb<pParse->db->nDb );
+      pSrc->a[pSrc->nSrc-1].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zName);
+    }
   }
   return pSrc;
 }
 
 /*
-** Generate VDBE code for zero or more statements inside the body of a
-** trigger.  
+** Generate VDBE code for the statements inside the body of a single 
+** trigger.
 */
 static int codeTriggerProgram(
   Parse *pParse,            /* The parser context */
   TriggerStep *pStepList,   /* List of statements inside the trigger body */
-  int orconfin              /* Conflict algorithm. (OE_Abort, etc) */  
+  int orconf                /* Conflict algorithm. (OE_Abort, etc) */  
 ){
-  TriggerStep * pTriggerStep = pStepList;
-  int orconf;
+  TriggerStep *pStep;
   Vdbe *v = pParse->pVdbe;
   sqlite3 *db = pParse->db;
 
-  assert( pTriggerStep!=0 );
+  assert( pParse->pTriggerTab && pParse->pToplevel );
+  assert( pStepList );
   assert( v!=0 );
-  sqlite3VdbeAddOp2(v, OP_ContextPush, 0, 0);
-  VdbeComment((v, "begin trigger %s", pStepList->pTrig->name));
-  while( pTriggerStep ){
-    sqlite3ExprClearColumnCache(pParse, -1);
-    orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
-    pParse->trigStack->orconf = orconf;
-    switch( pTriggerStep->op ){
-      case TK_SELECT: {
-        Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
-        if( ss ){
-          SelectDest dest;
+  for(pStep=pStepList; pStep; pStep=pStep->pNext){
+    /* Figure out the ON CONFLICT policy that will be used for this step
+    ** of the trigger program. If the statement that caused this trigger
+    ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use
+    ** the ON CONFLICT policy that was specified as part of the trigger
+    ** step statement. Example:
+    **
+    **   CREATE TRIGGER AFTER INSERT ON t1 BEGIN;
+    **     INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
+    **   END;
+    **
+    **   INSERT INTO t1 ... ;            -- insert into t2 uses REPLACE policy
+    **   INSERT OR IGNORE INTO t1 ... ;  -- insert into t2 uses IGNORE policy
+    */
+    pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;
 
-          sqlite3SelectDestInit(&dest, SRT_Discard, 0);
-          sqlite3Select(pParse, ss, &dest);
-          sqlite3SelectDelete(db, ss);
-        }
-        break;
-      }
+    switch( pStep->op ){
       case TK_UPDATE: {
-        SrcList *pSrc;
-        pSrc = targetSrcList(pParse, pTriggerStep);
-        sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
-        sqlite3Update(pParse, pSrc,
-                sqlite3ExprListDup(db, pTriggerStep->pExprList), 
-                sqlite3ExprDup(db, pTriggerStep->pWhere), orconf);
-        sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
+        sqlite3Update(pParse, 
+          targetSrcList(pParse, pStep),
+          sqlite3ExprListDup(db, pStep->pExprList, 0), 
+          sqlite3ExprDup(db, pStep->pWhere, 0), 
+          pParse->eOrconf
+        );
         break;
       }
       case TK_INSERT: {
-        SrcList *pSrc;
-        pSrc = targetSrcList(pParse, pTriggerStep);
-        sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
-        sqlite3Insert(pParse, pSrc,
-          sqlite3ExprListDup(db, pTriggerStep->pExprList), 
-          sqlite3SelectDup(db, pTriggerStep->pSelect), 
-          sqlite3IdListDup(db, pTriggerStep->pIdList), orconf);
-        sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
+        sqlite3Insert(pParse, 
+          targetSrcList(pParse, pStep),
+          sqlite3ExprListDup(db, pStep->pExprList, 0), 
+          sqlite3SelectDup(db, pStep->pSelect, 0), 
+          sqlite3IdListDup(db, pStep->pIdList), 
+          pParse->eOrconf
+        );
         break;
       }
       case TK_DELETE: {
-        SrcList *pSrc;
-        sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
-        pSrc = targetSrcList(pParse, pTriggerStep);
-        sqlite3DeleteFrom(pParse, pSrc, 
-                          sqlite3ExprDup(db, pTriggerStep->pWhere));
-        sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
+        sqlite3DeleteFrom(pParse, 
+          targetSrcList(pParse, pStep),
+          sqlite3ExprDup(db, pStep->pWhere, 0)
+        );
+        break;
+      }
+      default: assert( pStep->op==TK_SELECT ); {
+        SelectDest sDest;
+        Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0);
+        sqlite3SelectDestInit(&sDest, SRT_Discard, 0);
+        sqlite3Select(pParse, pSelect, &sDest);
+        sqlite3SelectDelete(db, pSelect);
         break;
       }
-      default:
-        assert(0);
     } 
-    pTriggerStep = pTriggerStep->pNext;
+    if( pStep->op!=TK_SELECT ){
+      sqlite3VdbeAddOp0(v, OP_ResetCount);
+    }
   }
-  sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0);
-  VdbeComment((v, "end trigger %s", pStepList->pTrig->name));
 
   return 0;
 }
 
+#ifdef SQLITE_DEBUG
 /*
-** This is called to code FOR EACH ROW triggers.
-**
-** When the code that this function generates is executed, the following 
-** must be true:
-**
-** 1. No cursors may be open in the main database.  (But newIdx and oldIdx
-**    can be indices of cursors in temporary tables.  See below.)
-**
-** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
-**    a temporary vdbe cursor (index newIdx) must be open and pointing at
-**    a row containing values to be substituted for new.* expressions in the
-**    trigger program(s).
-**
-** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
-**    a temporary vdbe cursor (index oldIdx) must be open and pointing at
-**    a row containing values to be substituted for old.* expressions in the
-**    trigger program(s).
-**
-** If they are not NULL, the piOldColMask and piNewColMask output variables
-** are set to values that describe the columns used by the trigger program
-** in the OLD.* and NEW.* tables respectively. If column N of the 
-** pseudo-table is read at least once, the corresponding bit of the output
-** mask is set. If a column with an index greater than 32 is read, the
-** output mask is set to the special value 0xffffffff.
-**
+** This function is used to add VdbeComment() annotations to a VDBE
+** program. It is not used in production code, only for debugging.
 */
-SQLITE_PRIVATE int sqlite3CodeRowTrigger(
+static const char *onErrorText(int onError){
+  switch( onError ){
+    case OE_Abort:    return "abort";
+    case OE_Rollback: return "rollback";
+    case OE_Fail:     return "fail";
+    case OE_Replace:  return "replace";
+    case OE_Ignore:   return "ignore";
+    case OE_Default:  return "default";
+  }
+  return "n/a";
+}
+#endif
+
+/*
+** Parse context structure pFrom has just been used to create a sub-vdbe
+** (trigger program). If an error has occurred, transfer error information
+** from pFrom to pTo.
+*/
+static void transferParseError(Parse *pTo, Parse *pFrom){
+  assert( pFrom->zErrMsg==0 || pFrom->nErr );
+  assert( pTo->zErrMsg==0 || pTo->nErr );
+  if( pTo->nErr==0 ){
+    pTo->zErrMsg = pFrom->zErrMsg;
+    pTo->nErr = pFrom->nErr;
+  }else{
+    sqlite3DbFree(pFrom->db, pFrom->zErrMsg);
+  }
+}
+
+/*
+** Create and populate a new TriggerPrg object with a sub-program 
+** implementing trigger pTrigger with ON CONFLICT policy orconf.
+*/
+static TriggerPrg *codeRowTrigger(
+  Parse *pParse,       /* Current parse context */
+  Trigger *pTrigger,   /* Trigger to code */
+  Table *pTab,         /* The table pTrigger is attached to */
+  int orconf           /* ON CONFLICT policy to code trigger program with */
+){
+  Parse *pTop = sqlite3ParseToplevel(pParse);
+  sqlite3 *db = pParse->db;   /* Database handle */
+  TriggerPrg *pPrg;           /* Value to return */
+  Expr *pWhen = 0;            /* Duplicate of trigger WHEN expression */
+  Vdbe *v;                    /* Temporary VM */
+  NameContext sNC;            /* Name context for sub-vdbe */
+  SubProgram *pProgram = 0;   /* Sub-vdbe for trigger program */
+  Parse *pSubParse;           /* Parse context for sub-vdbe */
+  int iEndTrigger = 0;        /* Label to jump to if WHEN is false */
+
+  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+  assert( pTop->pVdbe );
+
+  /* Allocate the TriggerPrg and SubProgram objects. To ensure that they
+  ** are freed if an error occurs, link them into the Parse.pTriggerPrg 
+  ** list of the top-level Parse object sooner rather than later.  */
+  pPrg = sqlite3DbMallocZero(db, sizeof(TriggerPrg));
+  if( !pPrg ) return 0;
+  pPrg->pNext = pTop->pTriggerPrg;
+  pTop->pTriggerPrg = pPrg;
+  pPrg->pProgram = pProgram = sqlite3DbMallocZero(db, sizeof(SubProgram));
+  if( !pProgram ) return 0;
+  sqlite3VdbeLinkSubProgram(pTop->pVdbe, pProgram);
+  pPrg->pTrigger = pTrigger;
+  pPrg->orconf = orconf;
+  pPrg->aColmask[0] = 0xffffffff;
+  pPrg->aColmask[1] = 0xffffffff;
+
+  /* Allocate and populate a new Parse context to use for coding the 
+  ** trigger sub-program.  */
+  pSubParse = sqlite3StackAllocZero(db, sizeof(Parse));
+  if( !pSubParse ) return 0;
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pSubParse;
+  pSubParse->db = db;
+  pSubParse->pTriggerTab = pTab;
+  pSubParse->pToplevel = pTop;
+  pSubParse->zAuthContext = pTrigger->zName;
+  pSubParse->eTriggerOp = pTrigger->op;
+  pSubParse->nQueryLoop = pParse->nQueryLoop;
+
+  v = sqlite3GetVdbe(pSubParse);
+  if( v ){
+    VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)", 
+      pTrigger->zName, onErrorText(orconf),
+      (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"),
+        (pTrigger->op==TK_UPDATE ? "UPDATE" : ""),
+        (pTrigger->op==TK_INSERT ? "INSERT" : ""),
+        (pTrigger->op==TK_DELETE ? "DELETE" : ""),
+      pTab->zName
+    ));
+#ifndef SQLITE_OMIT_TRACE
+    sqlite3VdbeChangeP4(v, -1, 
+      sqlite3MPrintf(db, "-- TRIGGER %s", pTrigger->zName), P4_DYNAMIC
+    );
+#endif
+
+    /* If one was specified, code the WHEN clause. If it evaluates to false
+    ** (or NULL) the sub-vdbe is immediately halted by jumping to the 
+    ** OP_Halt inserted at the end of the program.  */
+    if( pTrigger->pWhen ){
+      pWhen = sqlite3ExprDup(db, pTrigger->pWhen, 0);
+      if( SQLITE_OK==sqlite3ResolveExprNames(&sNC, pWhen) 
+       && db->mallocFailed==0 
+      ){
+        iEndTrigger = sqlite3VdbeMakeLabel(v);
+        sqlite3ExprIfFalse(pSubParse, pWhen, iEndTrigger, SQLITE_JUMPIFNULL);
+      }
+      sqlite3ExprDelete(db, pWhen);
+    }
+
+    /* Code the trigger program into the sub-vdbe. */
+    codeTriggerProgram(pSubParse, pTrigger->step_list, orconf);
+
+    /* Insert an OP_Halt at the end of the sub-program. */
+    if( iEndTrigger ){
+      sqlite3VdbeResolveLabel(v, iEndTrigger);
+    }
+    sqlite3VdbeAddOp0(v, OP_Halt);
+    VdbeComment((v, "End: %s.%s", pTrigger->zName, onErrorText(orconf)));
+
+    transferParseError(pParse, pSubParse);
+    if( db->mallocFailed==0 ){
+      pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pTop->nMaxArg);
+    }
+    pProgram->nMem = pSubParse->nMem;
+    pProgram->nCsr = pSubParse->nTab;
+    pProgram->nOnce = pSubParse->nOnce;
+    pProgram->token = (void *)pTrigger;
+    pPrg->aColmask[0] = pSubParse->oldmask;
+    pPrg->aColmask[1] = pSubParse->newmask;
+    sqlite3VdbeDelete(v);
+  }
+
+  assert( !pSubParse->pAinc       && !pSubParse->pZombieTab );
+  assert( !pSubParse->pTriggerPrg && !pSubParse->nMaxArg );
+  sqlite3StackFree(db, pSubParse);
+
+  return pPrg;
+}
+    
+/*
+** Return a pointer to a TriggerPrg object containing the sub-program for
+** trigger pTrigger with default ON CONFLICT algorithm orconf. If no such
+** TriggerPrg object exists, a new object is allocated and populated before
+** being returned.
+*/
+static TriggerPrg *getRowTrigger(
+  Parse *pParse,       /* Current parse context */
+  Trigger *pTrigger,   /* Trigger to code */
+  Table *pTab,         /* The table trigger pTrigger is attached to */
+  int orconf           /* ON CONFLICT algorithm. */
+){
+  Parse *pRoot = sqlite3ParseToplevel(pParse);
+  TriggerPrg *pPrg;
+
+  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+
+  /* It may be that this trigger has already been coded (or is in the
+  ** process of being coded). If this is the case, then an entry with
+  ** a matching TriggerPrg.pTrigger field will be present somewhere
+  ** in the Parse.pTriggerPrg list. Search for such an entry.  */
+  for(pPrg=pRoot->pTriggerPrg; 
+      pPrg && (pPrg->pTrigger!=pTrigger || pPrg->orconf!=orconf); 
+      pPrg=pPrg->pNext
+  );
+
+  /* If an existing TriggerPrg could not be located, create a new one. */
+  if( !pPrg ){
+    pPrg = codeRowTrigger(pParse, pTrigger, pTab, orconf);
+  }
+
+  return pPrg;
+}
+
+/*
+** Generate code for the trigger program associated with trigger p on 
+** table pTab. The reg, orconf and ignoreJump parameters passed to this
+** function are the same as those described in the header function for
+** sqlite3CodeRowTrigger()
+*/
+SQLITE_PRIVATE void sqlite3CodeRowTriggerDirect(
   Parse *pParse,       /* Parse context */
+  Trigger *p,          /* Trigger to code */
+  Table *pTab,         /* The table to code triggers from */
+  int reg,             /* Reg array containing OLD.* and NEW.* values */
+  int orconf,          /* ON CONFLICT policy */
+  int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */
+){
+  Vdbe *v = sqlite3GetVdbe(pParse); /* Main VM */
+  TriggerPrg *pPrg;
+  pPrg = getRowTrigger(pParse, p, pTab, orconf);
+  assert( pPrg || pParse->nErr || pParse->db->mallocFailed );
+
+  /* Code the OP_Program opcode in the parent VDBE. P4 of the OP_Program 
+  ** is a pointer to the sub-vdbe containing the trigger program.  */
+  if( pPrg ){
+    int bRecursive = (p->zName && 0==(pParse->db->flags&SQLITE_RecTriggers));
+
+    sqlite3VdbeAddOp3(v, OP_Program, reg, ignoreJump, ++pParse->nMem);
+    sqlite3VdbeChangeP4(v, -1, (const char *)pPrg->pProgram, P4_SUBPROGRAM);
+    VdbeComment(
+        (v, "Call: %s.%s", (p->zName?p->zName:"fkey"), onErrorText(orconf)));
+
+    /* Set the P5 operand of the OP_Program instruction to non-zero if
+    ** recursive invocation of this trigger program is disallowed. Recursive
+    ** invocation is disallowed if (a) the sub-program is really a trigger,
+    ** not a foreign key action, and (b) the flag to enable recursive triggers
+    ** is clear.  */
+    sqlite3VdbeChangeP5(v, (u8)bRecursive);
+  }
+}
+
+/*
+** This is called to code the required FOR EACH ROW triggers for an operation
+** on table pTab. The operation to code triggers for (INSERT, UPDATE or DELETE)
+** is given by the op paramater. The tr_tm parameter determines whether the
+** BEFORE or AFTER triggers are coded. If the operation is an UPDATE, then
+** parameter pChanges is passed the list of columns being modified.
+**
+** If there are no triggers that fire at the specified time for the specified
+** operation on pTab, this function is a no-op.
+**
+** The reg argument is the address of the first in an array of registers 
+** that contain the values substituted for the new.* and old.* references
+** in the trigger program. If N is the number of columns in table pTab
+** (a copy of pTab->nCol), then registers are populated as follows:
+**
+**   Register       Contains
+**   ------------------------------------------------------
+**   reg+0          OLD.rowid
+**   reg+1          OLD.* value of left-most column of pTab
+**   ...            ...
+**   reg+N          OLD.* value of right-most column of pTab
+**   reg+N+1        NEW.rowid
+**   reg+N+2        OLD.* value of left-most column of pTab
+**   ...            ...
+**   reg+N+N+1      NEW.* value of right-most column of pTab
+**
+** For ON DELETE triggers, the registers containing the NEW.* values will
+** never be accessed by the trigger program, so they are not allocated or 
+** populated by the caller (there is no data to populate them with anyway). 
+** Similarly, for ON INSERT triggers the values stored in the OLD.* registers
+** are never accessed, and so are not allocated by the caller. So, for an
+** ON INSERT trigger, the value passed to this function as parameter reg
+** is not a readable register, although registers (reg+N) through 
+** (reg+N+N+1) are.
+**
+** Parameter orconf is the default conflict resolution algorithm for the
+** trigger program to use (REPLACE, IGNORE etc.). Parameter ignoreJump
+** is the instruction that control should jump to if a trigger program
+** raises an IGNORE exception.
+*/
+SQLITE_PRIVATE void sqlite3CodeRowTrigger(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* List of triggers on table pTab */
   int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
   ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
   int tr_tm,           /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
   Table *pTab,         /* The table to code triggers from */
-  int newIdx,          /* The indice of the "new" row to access */
-  int oldIdx,          /* The indice of the "old" row to access */
+  int reg,             /* The first in an array of registers (see above) */
   int orconf,          /* ON CONFLICT policy */
-  int ignoreJump,      /* Instruction to jump to for RAISE(IGNORE) */
-  u32 *piOldColMask,   /* OUT: Mask of columns used from the OLD.* table */
-  u32 *piNewColMask    /* OUT: Mask of columns used from the NEW.* table */
+  int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */
 ){
-  Trigger *p;
-  sqlite3 *db = pParse->db;
-  TriggerStack trigStackEntry;
+  Trigger *p;          /* Used to iterate through pTrigger list */
 
-  trigStackEntry.oldColMask = 0;
-  trigStackEntry.newColMask = 0;
+  assert( op==TK_UPDATE || op==TK_INSERT || op==TK_DELETE );
+  assert( tr_tm==TRIGGER_BEFORE || tr_tm==TRIGGER_AFTER );
+  assert( (op==TK_UPDATE)==(pChanges!=0) );
 
-  assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
-  assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
+  for(p=pTrigger; p; p=p->pNext){
 
-  assert(newIdx != -1 || oldIdx != -1);
-
-  for(p=pTab->pTrigger; p; p=p->pNext){
-    int fire_this = 0;
+    /* Sanity checking:  The schema for the trigger and for the table are
+    ** always defined.  The trigger must be in the same schema as the table
+    ** or else it must be a TEMP trigger. */
+    assert( p->pSchema!=0 );
+    assert( p->pTabSchema!=0 );
+    assert( p->pSchema==p->pTabSchema 
+         || p->pSchema==pParse->db->aDb[1].pSchema );
 
     /* Determine whether we should code this trigger */
-    if( 
-      p->op==op && 
-      p->tr_tm==tr_tm && 
-      (p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema) &&
-      (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))
+    if( p->op==op 
+     && p->tr_tm==tr_tm 
+     && checkColumnOverlap(p->pColumns, pChanges)
     ){
-      TriggerStack *pS;      /* Pointer to trigger-stack entry */
-      for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){}
-      if( !pS ){
-        fire_this = 1;
-      }
-#if 0    /* Give no warning for recursive triggers.  Just do not do them */
-      else{
-        sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)",
-            p->name);
-        return SQLITE_ERROR;
-      }
-#endif
-    }
- 
-    if( fire_this ){
-      int endTrigger;
-      Expr * whenExpr;
-      AuthContext sContext;
-      NameContext sNC;
-
-#ifndef SQLITE_OMIT_TRACE
-      sqlite3VdbeAddOp4(pParse->pVdbe, OP_Trace, 0, 0, 0,
-                        sqlite3MPrintf(db, "-- TRIGGER %s", p->name),
-                        P4_DYNAMIC);
-#endif
-      memset(&sNC, 0, sizeof(sNC));
-      sNC.pParse = pParse;
-
-      /* Push an entry on to the trigger stack */
-      trigStackEntry.pTrigger = p;
-      trigStackEntry.newIdx = newIdx;
-      trigStackEntry.oldIdx = oldIdx;
-      trigStackEntry.pTab = pTab;
-      trigStackEntry.pNext = pParse->trigStack;
-      trigStackEntry.ignoreJump = ignoreJump;
-      pParse->trigStack = &trigStackEntry;
-      sqlite3AuthContextPush(pParse, &sContext, p->name);
-
-      /* code the WHEN clause */
-      endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
-      whenExpr = sqlite3ExprDup(db, p->pWhen);
-      if( db->mallocFailed || sqlite3ResolveExprNames(&sNC, whenExpr) ){
-        pParse->trigStack = trigStackEntry.pNext;
-        sqlite3ExprDelete(db, whenExpr);
-        return 1;
-      }
-      sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, SQLITE_JUMPIFNULL);
-      sqlite3ExprDelete(db, whenExpr);
-
-      codeTriggerProgram(pParse, p->step_list, orconf); 
-
-      /* Pop the entry off the trigger stack */
-      pParse->trigStack = trigStackEntry.pNext;
-      sqlite3AuthContextPop(&sContext);
-
-      sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger);
+      sqlite3CodeRowTriggerDirect(pParse, p, pTab, reg, orconf, ignoreJump);
     }
   }
-  if( piOldColMask ) *piOldColMask |= trigStackEntry.oldColMask;
-  if( piNewColMask ) *piNewColMask |= trigStackEntry.newColMask;
-  return 0;
 }
+
+/*
+** Triggers may access values stored in the old.* or new.* pseudo-table. 
+** This function returns a 32-bit bitmask indicating which columns of the 
+** old.* or new.* tables actually are used by triggers. This information 
+** may be used by the caller, for example, to avoid having to load the entire
+** old.* record into memory when executing an UPDATE or DELETE command.
+**
+** Bit 0 of the returned mask is set if the left-most column of the
+** table may be accessed using an [old|new].<col> reference. Bit 1 is set if
+** the second leftmost column value is required, and so on. If there
+** are more than 32 columns in the table, and at least one of the columns
+** with an index greater than 32 may be accessed, 0xffffffff is returned.
+**
+** It is not possible to determine if the old.rowid or new.rowid column is 
+** accessed by triggers. The caller must always assume that it is.
+**
+** Parameter isNew must be either 1 or 0. If it is 0, then the mask returned
+** applies to the old.* table. If 1, the new.* table.
+**
+** Parameter tr_tm must be a mask with one or both of the TRIGGER_BEFORE
+** and TRIGGER_AFTER bits set. Values accessed by BEFORE triggers are only
+** included in the returned mask if the TRIGGER_BEFORE bit is set in the
+** tr_tm parameter. Similarly, values accessed by AFTER triggers are only
+** included in the returned mask if the TRIGGER_AFTER bit is set in tr_tm.
+*/
+SQLITE_PRIVATE u32 sqlite3TriggerColmask(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* List of triggers on table pTab */
+  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
+  int isNew,           /* 1 for new.* ref mask, 0 for old.* ref mask */
+  int tr_tm,           /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+  Table *pTab,         /* The table to code triggers from */
+  int orconf           /* Default ON CONFLICT policy for trigger steps */
+){
+  const int op = pChanges ? TK_UPDATE : TK_DELETE;
+  u32 mask = 0;
+  Trigger *p;
+
+  assert( isNew==1 || isNew==0 );
+  for(p=pTrigger; p; p=p->pNext){
+    if( p->op==op && (tr_tm&p->tr_tm)
+     && checkColumnOverlap(p->pColumns,pChanges)
+    ){
+      TriggerPrg *pPrg;
+      pPrg = getRowTrigger(pParse, p, pTab, orconf);
+      if( pPrg ){
+        mask |= pPrg->aColmask[isNew];
+      }
+    }
+  }
+
+  return mask;
+}
+
 #endif /* !defined(SQLITE_OMIT_TRIGGER) */
 
 /************** End of trigger.c *********************************************/
@@ -77638,8 +99537,6 @@ SQLITE_PRIVATE int sqlite3CodeRowTrigger(
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** to handle UPDATE statements.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
@@ -77651,7 +99548,8 @@ static void updateVirtualTable(
   ExprList *pChanges,  /* The columns to change in the UPDATE statement */
   Expr *pRowidExpr,    /* Expression used to recompute the rowid */
   int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
-  Expr *pWhere         /* WHERE clause of the UPDATE statement */
+  Expr *pWhere,        /* WHERE clause of the UPDATE statement */
+  int onError          /* ON CONFLICT strategy */
 );
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
@@ -77679,9 +99577,15 @@ static void updateVirtualTable(
 ** the column is a literal number, string or null. The sqlite3ValueFromExpr()
 ** function is capable of transforming these types of expressions into
 ** sqlite3_value objects.
+**
+** If parameter iReg is not negative, code an OP_RealAffinity instruction
+** on register iReg. This is used when an equivalent integer value is 
+** stored in place of an 8-byte floating point value in order to save 
+** space.
 */
-SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
-  if( pTab && !pTab->pSelect ){
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i, int iReg){
+  assert( pTab!=0 );
+  if( !pTab->pSelect ){
     sqlite3_value *pValue;
     u8 enc = ENC(sqlite3VdbeDb(v));
     Column *pCol = &pTab->aCol[i];
@@ -77692,6 +99596,11 @@ SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
     if( pValue ){
       sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
     }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    if( iReg>=0 && pTab->aCol[i].affinity==SQLITE_AFF_REAL ){
+      sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
+    }
+#endif
   }
 }
 
@@ -77728,31 +99637,25 @@ SQLITE_PRIVATE void sqlite3Update(
   AuthContext sContext;  /* The authorization context */
   NameContext sNC;       /* The name-context to resolve expressions in */
   int iDb;               /* Database containing the table being updated */
-  int j1;                /* Addresses of jump instructions */
   int okOnePass;         /* True for one-pass algorithm without the FIFO */
+  int hasFK;             /* True if foreign key processing is required */
 
 #ifndef SQLITE_OMIT_TRIGGER
-  int isView;                  /* Trying to update a view */
-  int triggers_exist = 0;      /* True if any row triggers exist */
+  int isView;            /* True when updating a view (INSTEAD OF trigger) */
+  Trigger *pTrigger;     /* List of triggers on pTab, if required */
+  int tmask;             /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
 #endif
-  int iBeginAfterTrigger = 0;  /* Address of after trigger program */
-  int iEndAfterTrigger = 0;    /* Exit of after trigger program */
-  int iBeginBeforeTrigger = 0; /* Address of before trigger program */
-  int iEndBeforeTrigger = 0;   /* Exit of before trigger program */
-  u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
-  u32 new_col_mask = 0;        /* Mask of NEW.* columns in use */
-
-  int newIdx      = -1;  /* index of trigger "new" temp table       */
-  int oldIdx      = -1;  /* index of trigger "old" temp table       */
+  int newmask;           /* Mask of NEW.* columns accessed by BEFORE triggers */
 
   /* Register Allocations */
   int regRowCount = 0;   /* A count of rows changed */
   int regOldRowid;       /* The old rowid */
   int regNewRowid;       /* The new rowid */
-  int regData;           /* New data for the row */
+  int regNew;            /* Content of the NEW.* table in triggers */
+  int regOld = 0;        /* Content of OLD.* table in triggers */
   int regRowSet = 0;     /* Rowset of rows to be updated */
 
-  sContext.pParse = 0;
+  memset(&sContext, 0, sizeof(sContext));
   db = pParse->db;
   if( pParse->nErr || db->mallocFailed ){
     goto update_cleanup;
@@ -77766,38 +99669,32 @@ SQLITE_PRIVATE void sqlite3Update(
   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
 
   /* Figure out if we have any triggers and if the table being
-  ** updated is a view
+  ** updated is a view.
   */
 #ifndef SQLITE_OMIT_TRIGGER
-  triggers_exist = sqlite3TriggersExist(pTab, TK_UPDATE, pChanges);
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, &tmask);
   isView = pTab->pSelect!=0;
+  assert( pTrigger || tmask==0 );
 #else
-# define triggers_exist 0
+# define pTrigger 0
 # define isView 0
+# define tmask 0
 #endif
 #ifdef SQLITE_OMIT_VIEW
 # undef isView
 # define isView 0
 #endif
 
-  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
     goto update_cleanup;
   }
-  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+  if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
     goto update_cleanup;
   }
   aXRef = sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol );
   if( aXRef==0 ) goto update_cleanup;
   for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
 
-  /* If there are FOR EACH ROW triggers, allocate cursors for the
-  ** special OLD and NEW tables
-  */
-  if( triggers_exist ){
-    newIdx = pParse->nTab++;
-    oldIdx = pParse->nTab++;
-  }
-
   /* Allocate a cursors for the main database table and for all indices.
   ** The index cursors might not be used, but if they are used they
   ** need to occur right after the database cursor.  So go ahead and
@@ -77840,6 +99737,7 @@ SQLITE_PRIVATE void sqlite3Update(
         pRowidExpr = pChanges->a[i].pExpr;
       }else{
         sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
+        pParse->checkSchema = 1;
         goto update_cleanup;
       }
     }
@@ -77857,6 +99755,8 @@ SQLITE_PRIVATE void sqlite3Update(
 #endif
   }
 
+  hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngRowid);
+
   /* Allocate memory for the array aRegIdx[].  There is one entry in the
   ** array for each index associated with table being updated.  Fill in
   ** the value with a register number for indices that are to be used
@@ -77869,7 +99769,7 @@ SQLITE_PRIVATE void sqlite3Update(
   }
   for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
     int reg;
-    if( chngRowid ){
+    if( hasFK || chngRowid ){
       reg = ++pParse->nMem;
     }else{
       reg = 0;
@@ -77883,24 +99783,7 @@ SQLITE_PRIVATE void sqlite3Update(
     aRegIdx[j] = reg;
   }
 
-  /* Allocate a block of register used to store the change record
-  ** sent to sqlite3GenerateConstraintChecks().  There are either
-  ** one or two registers for holding the rowid.  One rowid register
-  ** is used if chngRowid is false and two are used if chngRowid is
-  ** true.  Following these are pTab->nCol register holding column
-  ** data.
-  */
-  regOldRowid = regNewRowid = pParse->nMem + 1;
-  pParse->nMem += pTab->nCol + 1;
-  if( chngRowid ){
-    regNewRowid++;
-    pParse->nMem++;
-  }
-  regData = regNewRowid+1;
- 
-
-  /* Begin generating code.
-  */
+  /* Begin generating code. */
   v = sqlite3GetVdbe(pParse);
   if( v==0 ) goto update_cleanup;
   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
@@ -77910,48 +99793,31 @@ SQLITE_PRIVATE void sqlite3Update(
   /* Virtual tables must be handled separately */
   if( IsVirtual(pTab) ){
     updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
-                       pWhere);
+                       pWhere, onError);
     pWhere = 0;
     pTabList = 0;
     goto update_cleanup;
   }
 #endif
 
-  /* Start the view context
-  */
+  /* Allocate required registers. */
+  regRowSet = ++pParse->nMem;
+  regOldRowid = regNewRowid = ++pParse->nMem;
+  if( pTrigger || hasFK ){
+    regOld = pParse->nMem + 1;
+    pParse->nMem += pTab->nCol;
+  }
+  if( chngRowid || pTrigger || hasFK ){
+    regNewRowid = ++pParse->nMem;
+  }
+  regNew = pParse->nMem + 1;
+  pParse->nMem += pTab->nCol;
+
+  /* Start the view context. */
   if( isView ){
     sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
   }
 
-  /* Generate the code for triggers.
-  */
-  if( triggers_exist ){
-    int iGoto;
-
-    /* Create pseudo-tables for NEW and OLD
-    */
-    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
-    sqlite3VdbeAddOp2(v, OP_OpenPseudo, oldIdx, 0);
-    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
-    sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0);
-
-    iGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
-    addr = sqlite3VdbeMakeLabel(v);
-    iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
-    if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab,
-          newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
-      goto update_cleanup;
-    }
-    iEndBeforeTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
-    iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v);
-    if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab, 
-          newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
-      goto update_cleanup;
-    }
-    iEndAfterTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
-    sqlite3VdbeJumpHere(v, iGoto);
-  }
-
   /* If we are trying to update a view, realize that view into
   ** a ephemeral table.
   */
@@ -77970,17 +99836,17 @@ SQLITE_PRIVATE void sqlite3Update(
 
   /* Begin the database scan
   */
-  sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
-  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
-                             WHERE_ONEPASS_DESIRED, 0);
+  sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
+  pWInfo = sqlite3WhereBegin(
+      pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED, 0
+  );
   if( pWInfo==0 ) goto update_cleanup;
   okOnePass = pWInfo->okOnePass;
 
   /* Remember the rowid of every item to be updated.
   */
-  sqlite3VdbeAddOp2(v, IsVirtual(pTab)?OP_VRowid:OP_Rowid, iCur, regOldRowid);
+  sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regOldRowid);
   if( !okOnePass ){
-    regRowSet = ++pParse->nMem;
     sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid);
   }
 
@@ -77990,12 +99856,12 @@ SQLITE_PRIVATE void sqlite3Update(
 
   /* Initialize the count of updated rows
   */
-  if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
+  if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab ){
     regRowCount = ++pParse->nMem;
     sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
   }
 
-  if( !isView && !IsVirtual(pTab) ){
+  if( !isView ){
     /* 
     ** Open every index that needs updating.  Note that if any
     ** index could potentially invoke a REPLACE conflict resolution 
@@ -78015,6 +99881,7 @@ SQLITE_PRIVATE void sqlite3Update(
       }
     }
     for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+      assert( aRegIdx );
       if( openAll || aRegIdx[i]>0 ){
         KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
         sqlite3VdbeAddOp4(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, iDb,
@@ -78023,11 +99890,6 @@ SQLITE_PRIVATE void sqlite3Update(
       }
     }
   }
-  
-  /* Jump back to this point if a trigger encounters an IGNORE constraint. */
-  if( triggers_exist ){
-    sqlite3VdbeResolveLabel(v, addr);
-  }
 
   /* Top of the update loop */
   if( okOnePass ){
@@ -78038,139 +99900,153 @@ SQLITE_PRIVATE void sqlite3Update(
     addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, regRowSet, 0, regOldRowid);
   }
 
-  if( triggers_exist ){
-    int regRowid;
-    int regRow;
-    int regCols;
+  /* Make cursor iCur point to the record that is being updated. If
+  ** this record does not exist for some reason (deleted by a trigger,
+  ** for example, then jump to the next iteration of the RowSet loop.  */
+  sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
 
-    /* Make cursor iCur point to the record that is being updated.
-    */
-    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
-
-    /* Generate the OLD table
-    */
-    regRowid = sqlite3GetTempReg(pParse);
-    regRow = sqlite3GetTempReg(pParse);
-    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
-    if( !old_col_mask ){
-      sqlite3VdbeAddOp2(v, OP_Null, 0, regRow);
-    }else{
-      sqlite3VdbeAddOp2(v, OP_RowData, iCur, regRow);
-    }
-    sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, regRow, regRowid);
-
-    /* Generate the NEW table
-    */
-    if( chngRowid ){
-      sqlite3ExprCodeAndCache(pParse, pRowidExpr, regRowid);
-      sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid);
-    }else{
-      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
-    }
-    regCols = sqlite3GetTempRange(pParse, pTab->nCol);
-    for(i=0; i<pTab->nCol; i++){
-      if( i==pTab->iPKey ){
-        sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
-        continue;
-      }
-      j = aXRef[i];
-      if( new_col_mask&((u32)1<<i) || new_col_mask==0xffffffff ){
-        if( j<0 ){
-          sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regCols+i);
-          sqlite3ColumnDefault(v, pTab, i);
-        }else{
-          sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr, regCols+i);
-        }
-      }else{
-        sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
-      }
-    }
-    sqlite3VdbeAddOp3(v, OP_MakeRecord, regCols, pTab->nCol, regRow);
-    if( !isView ){
-      sqlite3TableAffinityStr(v, pTab);
-      sqlite3ExprCacheAffinityChange(pParse, regCols, pTab->nCol);
-    }
-    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol);
-    /* if( pParse->nErr ) goto update_cleanup; */
-    sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRow, regRowid);
-    sqlite3ReleaseTempReg(pParse, regRowid);
-    sqlite3ReleaseTempReg(pParse, regRow);
-
-    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
-    sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
+  /* If the record number will change, set register regNewRowid to
+  ** contain the new value. If the record number is not being modified,
+  ** then regNewRowid is the same register as regOldRowid, which is
+  ** already populated.  */
+  assert( chngRowid || pTrigger || hasFK || regOldRowid==regNewRowid );
+  if( chngRowid ){
+    sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
+    sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid);
   }
 
-  if( !isView && !IsVirtual(pTab) ){
-    /* Loop over every record that needs updating.  We have to load
-    ** the old data for each record to be updated because some columns
-    ** might not change and we will need to copy the old value.
-    ** Also, the old data is needed to delete the old index entries.
-    ** So make the cursor point at the old record.
+  /* If there are triggers on this table, populate an array of registers 
+  ** with the required old.* column data.  */
+  if( hasFK || pTrigger ){
+    u32 oldmask = (hasFK ? sqlite3FkOldmask(pParse, pTab) : 0);
+    oldmask |= sqlite3TriggerColmask(pParse, 
+        pTrigger, pChanges, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onError
+    );
+    for(i=0; i<pTab->nCol; i++){
+      if( aXRef[i]<0 || oldmask==0xffffffff || (i<32 && (oldmask & (1<<i))) ){
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, i, regOld+i);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regOld+i);
+      }
+    }
+    if( chngRowid==0 ){
+      sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
+    }
+  }
+
+  /* Populate the array of registers beginning at regNew with the new
+  ** row data. This array is used to check constaints, create the new
+  ** table and index records, and as the values for any new.* references
+  ** made by triggers.
+  **
+  ** If there are one or more BEFORE triggers, then do not populate the
+  ** registers associated with columns that are (a) not modified by
+  ** this UPDATE statement and (b) not accessed by new.* references. The
+  ** values for registers not modified by the UPDATE must be reloaded from 
+  ** the database after the BEFORE triggers are fired anyway (as the trigger 
+  ** may have modified them). So not loading those that are not going to
+  ** be used eliminates some redundant opcodes.
+  */
+  newmask = sqlite3TriggerColmask(
+      pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
+  );
+  sqlite3VdbeAddOp3(v, OP_Null, 0, regNew, regNew+pTab->nCol-1);
+  for(i=0; i<pTab->nCol; i++){
+    if( i==pTab->iPKey ){
+      /*sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);*/
+    }else{
+      j = aXRef[i];
+      if( j>=0 ){
+        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);
+      }else if( 0==(tmask&TRIGGER_BEFORE) || i>31 || (newmask&(1<<i)) ){
+        /* This branch loads the value of a column that will not be changed 
+        ** into a register. This is done if there are no BEFORE triggers, or
+        ** if there are one or more BEFORE triggers that use this value via
+        ** a new.* reference in a trigger program.
+        */
+        testcase( i==31 );
+        testcase( i==32 );
+        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regNew+i);
+        sqlite3ColumnDefault(v, pTab, i, regNew+i);
+      }
+    }
+  }
+
+  /* Fire any BEFORE UPDATE triggers. This happens before constraints are
+  ** verified. One could argue that this is wrong.
+  */
+  if( tmask&TRIGGER_BEFORE ){
+    sqlite3VdbeAddOp2(v, OP_Affinity, regNew, pTab->nCol);
+    sqlite3TableAffinityStr(v, pTab);
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges, 
+        TRIGGER_BEFORE, pTab, regOldRowid, onError, addr);
+
+    /* The row-trigger may have deleted the row being updated. In this
+    ** case, jump to the next row. No updates or AFTER triggers are 
+    ** required. This behaviour - what happens when the row being updated
+    ** is deleted or renamed by a BEFORE trigger - is left undefined in the
+    ** documentation.
     */
     sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
 
-    /* If the record number will change, push the record number as it
-    ** will be after the update. (The old record number is currently
-    ** on top of the stack.)
-    */
-    if( chngRowid ){
-      sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
-      sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid);
-    }
-
-    /* Compute new data for this record.  
+    /* If it did not delete it, the row-trigger may still have modified 
+    ** some of the columns of the row being updated. Load the values for 
+    ** all columns not modified by the update statement into their 
+    ** registers in case this has happened.
     */
     for(i=0; i<pTab->nCol; i++){
-      if( i==pTab->iPKey ){
-        sqlite3VdbeAddOp2(v, OP_Null, 0, regData+i);
-        continue;
-      }
-      j = aXRef[i];
-      if( j<0 ){
-        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regData+i);
-        sqlite3ColumnDefault(v, pTab, i);
-      }else{
-        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regData+i);
+      if( aXRef[i]<0 && i!=pTab->iPKey ){
+        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regNew+i);
+        sqlite3ColumnDefault(v, pTab, i, regNew+i);
       }
     }
+  }
 
-    /* Do constraint checks
-    */
+  if( !isView ){
+    int j1;                       /* Address of jump instruction */
+
+    /* Do constraint checks. */
     sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid,
-                                    aRegIdx, chngRowid, 1,
-                                    onError, addr);
+        aRegIdx, (chngRowid?regOldRowid:0), 1, onError, addr, 0);
 
-    /* Delete the old indices for the current record.
-    */
+    /* Do FK constraint checks. */
+    if( hasFK ){
+      sqlite3FkCheck(pParse, pTab, regOldRowid, 0);
+    }
+
+    /* Delete the index entries associated with the current record.  */
     j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regOldRowid);
     sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, aRegIdx);
-
-    /* If changing the record number, delete the old record.
-    */
-    if( chngRowid ){
+  
+    /* If changing the record number, delete the old record.  */
+    if( hasFK || chngRowid ){
       sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
     }
     sqlite3VdbeJumpHere(v, j1);
 
-    /* Create the new index entries and the new record.
-    */
-    sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, 
-                             aRegIdx, 1, -1, 0);
+    if( hasFK ){
+      sqlite3FkCheck(pParse, pTab, 0, regNewRowid);
+    }
+  
+    /* Insert the new index entries and the new record. */
+    sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, aRegIdx, 1, 0, 0);
+
+    /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+    ** handle rows (possibly in other tables) that refer via a foreign key
+    ** to the row just updated. */ 
+    if( hasFK ){
+      sqlite3FkActions(pParse, pTab, pChanges, regOldRowid);
+    }
   }
 
   /* Increment the row counter 
   */
-  if( db->flags & SQLITE_CountRows && !pParse->trigStack){
+  if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab){
     sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
   }
 
-  /* If there are triggers, close all the cursors after each iteration
-  ** through the loop.  The fire the after triggers.
-  */
-  if( triggers_exist ){
-    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
-    sqlite3VdbeJumpHere(v, iEndAfterTrigger);
-  }
+  sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges, 
+      TRIGGER_AFTER, pTab, regOldRowid, onError, addr);
 
   /* Repeat the above with the next record to be updated, until
   ** all record selected by the WHERE clause have been updated.
@@ -78180,14 +100056,19 @@ SQLITE_PRIVATE void sqlite3Update(
 
   /* Close all tables */
   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+    assert( aRegIdx );
     if( openAll || aRegIdx[i]>0 ){
       sqlite3VdbeAddOp2(v, OP_Close, iCur+i+1, 0);
     }
   }
   sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
-  if( triggers_exist ){
-    sqlite3VdbeAddOp2(v, OP_Close, newIdx, 0);
-    sqlite3VdbeAddOp2(v, OP_Close, oldIdx, 0);
+
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
+    sqlite3AutoincrementEnd(pParse);
   }
 
   /*
@@ -78195,7 +100076,7 @@ SQLITE_PRIVATE void sqlite3Update(
   ** generating code because of a call to sqlite3NestedParse(), do not
   ** invoke the callback function.
   */
-  if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
+  if( (db->flags&SQLITE_CountRows) && !pParse->pTriggerTab && !pParse->nested ){
     sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
     sqlite3VdbeSetNumCols(v, 1);
     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", SQLITE_STATIC);
@@ -78210,6 +100091,15 @@ update_cleanup:
   sqlite3ExprDelete(db, pWhere);
   return;
 }
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** thely may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /*
@@ -78238,7 +100128,8 @@ static void updateVirtualTable(
   ExprList *pChanges,  /* The columns to change in the UPDATE statement */
   Expr *pRowid,        /* Expression used to recompute the rowid */
   int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
-  Expr *pWhere         /* WHERE clause of the UPDATE statement */
+  Expr *pWhere,        /* WHERE clause of the UPDATE statement */
+  int onError          /* ON CONFLICT strategy */
 ){
   Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
   ExprList *pEList = 0;     /* The result set of the SELECT statement */
@@ -78249,26 +100140,25 @@ static void updateVirtualTable(
   int addr;                 /* Address of top of loop */
   int iReg;                 /* First register in set passed to OP_VUpdate */
   sqlite3 *db = pParse->db; /* Database connection */
-  const char *pVtab = (const char*)pTab->pVtab;
+  const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
   SelectDest dest;
 
   /* Construct the SELECT statement that will find the new values for
   ** all updated rows. 
   */
-  pEList = sqlite3ExprListAppend(pParse, 0, 
-                                 sqlite3CreateIdExpr(pParse, "_rowid_"), 0);
+  pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, "_rowid_"));
   if( pRowid ){
     pEList = sqlite3ExprListAppend(pParse, pEList,
-                                   sqlite3ExprDup(db, pRowid), 0);
+                                   sqlite3ExprDup(db, pRowid, 0));
   }
   assert( pTab->iPKey<0 );
   for(i=0; i<pTab->nCol; i++){
     if( aXRef[i]>=0 ){
-      pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr);
+      pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0);
     }else{
-      pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName);
+      pExpr = sqlite3Expr(db, TK_ID, pTab->aCol[i].zName);
     }
-    pEList = sqlite3ExprListAppend(pParse, pEList, pExpr, 0);
+    pEList = sqlite3ExprListAppend(pParse, pEList, pExpr);
   }
   pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
   
@@ -78278,6 +100168,7 @@ static void updateVirtualTable(
   assert( v );
   ephemTab = pParse->nTab++;
   sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
+  sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
 
   /* fill the ephemeral table 
   */
@@ -78287,17 +100178,18 @@ static void updateVirtualTable(
   /* Generate code to scan the ephemeral table and call VUpdate. */
   iReg = ++pParse->nMem;
   pParse->nMem += pTab->nCol+1;
-  sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
-  addr = sqlite3VdbeCurrentAddr(v);
+  addr = sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
   sqlite3VdbeAddOp3(v, OP_Column,  ephemTab, 0, iReg);
   sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
   for(i=0; i<pTab->nCol; i++){
     sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
   }
   sqlite3VtabMakeWritable(pParse, pTab);
-  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVtab, P4_VTAB);
-  sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr);
-  sqlite3VdbeJumpHere(v, addr-1);
+  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVTab, P4_VTAB);
+  sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
+  sqlite3MayAbort(pParse);
+  sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1);
+  sqlite3VdbeJumpHere(v, addr);
   sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
 
   /* Cleanup */
@@ -78305,11 +100197,6 @@ static void updateVirtualTable(
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
-/* Make sure "isView" gets undefined in case this file becomes part of
-** the amalgamation - so that subsequent files do not see isView as a
-** macro. */
-#undef isView
-
 /************** End of update.c **********************************************/
 /************** Begin file vacuum.c ******************************************/
 /*
@@ -78327,31 +100214,45 @@ static void updateVirtualTable(
 **
 ** Most of the code in this file may be omitted by defining the
 ** SQLITE_OMIT_VACUUM macro.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 #if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+/*
+** Finalize a prepared statement.  If there was an error, store the
+** text of the error message in *pzErrMsg.  Return the result code.
+*/
+static int vacuumFinalize(sqlite3 *db, sqlite3_stmt *pStmt, char **pzErrMsg){
+  int rc;
+  rc = sqlite3VdbeFinalize((Vdbe*)pStmt);
+  if( rc ){
+    sqlite3SetString(pzErrMsg, db, sqlite3_errmsg(db));
+  }
+  return rc;
+}
+
 /*
 ** Execute zSql on database db. Return an error code.
 */
-static int execSql(sqlite3 *db, const char *zSql){
+static int execSql(sqlite3 *db, char **pzErrMsg, const char *zSql){
   sqlite3_stmt *pStmt;
+  VVA_ONLY( int rc; )
   if( !zSql ){
     return SQLITE_NOMEM;
   }
   if( SQLITE_OK!=sqlite3_prepare(db, zSql, -1, &pStmt, 0) ){
+    sqlite3SetString(pzErrMsg, db, sqlite3_errmsg(db));
     return sqlite3_errcode(db);
   }
-  while( SQLITE_ROW==sqlite3_step(pStmt) ){}
-  return sqlite3_finalize(pStmt);
+  VVA_ONLY( rc = ) sqlite3_step(pStmt);
+  assert( rc!=SQLITE_ROW || (db->flags&SQLITE_CountRows) );
+  return vacuumFinalize(db, pStmt, pzErrMsg);
 }
 
 /*
 ** Execute zSql on database db. The statement returns exactly
 ** one column. Execute this as SQL on the same database.
 */
-static int execExecSql(sqlite3 *db, const char *zSql){
+static int execExecSql(sqlite3 *db, char **pzErrMsg, const char *zSql){
   sqlite3_stmt *pStmt;
   int rc;
 
@@ -78359,14 +100260,14 @@ static int execExecSql(sqlite3 *db, const char *zSql){
   if( rc!=SQLITE_OK ) return rc;
 
   while( SQLITE_ROW==sqlite3_step(pStmt) ){
-    rc = execSql(db, (char*)sqlite3_column_text(pStmt, 0));
+    rc = execSql(db, pzErrMsg, (char*)sqlite3_column_text(pStmt, 0));
     if( rc!=SQLITE_OK ){
-      sqlite3_finalize(pStmt);
+      vacuumFinalize(db, pStmt, pzErrMsg);
       return rc;
     }
   }
 
-  return sqlite3_finalize(pStmt);
+  return vacuumFinalize(db, pStmt, pzErrMsg);
 }
 
 /*
@@ -78393,30 +100294,39 @@ SQLITE_PRIVATE void sqlite3Vacuum(Parse *pParse){
 SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
   int rc = SQLITE_OK;     /* Return code from service routines */
   Btree *pMain;           /* The database being vacuumed */
-  Pager *pMainPager;      /* Pager for database being vacuumed */
   Btree *pTemp;           /* The temporary database we vacuum into */
   char *zSql = 0;         /* SQL statements */
   int saved_flags;        /* Saved value of the db->flags */
   int saved_nChange;      /* Saved value of db->nChange */
   int saved_nTotalChange; /* Saved value of db->nTotalChange */
+  void (*saved_xTrace)(void*,const char*);  /* Saved db->xTrace */
   Db *pDb = 0;            /* Database to detach at end of vacuum */
-  int isMemDb;            /* True is vacuuming a :memory: database */
-  int nRes;
-
-  /* Save the current value of the write-schema flag before setting it. */
-  saved_flags = db->flags;
-  saved_nChange = db->nChange;
-  saved_nTotalChange = db->nTotalChange;
-  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
+  int isMemDb;            /* True if vacuuming a :memory: database */
+  int nRes;               /* Bytes of reserved space at the end of each page */
+  int nDb;                /* Number of attached databases */
 
   if( !db->autoCommit ){
     sqlite3SetString(pzErrMsg, db, "cannot VACUUM from within a transaction");
-    rc = SQLITE_ERROR;
-    goto end_of_vacuum;
+    return SQLITE_ERROR;
   }
+  if( db->activeVdbeCnt>1 ){
+    sqlite3SetString(pzErrMsg, db,"cannot VACUUM - SQL statements in progress");
+    return SQLITE_ERROR;
+  }
+
+  /* Save the current value of the database flags so that it can be 
+  ** restored before returning. Then set the writable-schema flag, and
+  ** disable CHECK and foreign key constraints.  */
+  saved_flags = db->flags;
+  saved_nChange = db->nChange;
+  saved_nTotalChange = db->nTotalChange;
+  saved_xTrace = db->xTrace;
+  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks | SQLITE_PreferBuiltin;
+  db->flags &= ~(SQLITE_ForeignKeys | SQLITE_ReverseOrder);
+  db->xTrace = 0;
+
   pMain = db->aDb[0].pBt;
-  pMainPager = sqlite3BtreePager(pMain);
-  isMemDb = sqlite3PagerFile(pMainPager)->pMethods==0;
+  isMemDb = sqlite3PagerIsMemdb(sqlite3BtreePager(pMain));
 
   /* Attach the temporary database as 'vacuum_db'. The synchronous pragma
   ** can be set to 'off' for this file, as it is not recovered if a crash
@@ -78432,13 +100342,26 @@ SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
   ** time to parse and run the PRAGMA to turn journalling off than it does
   ** to write the journal header file.
   */
-  zSql = "ATTACH '' AS vacuum_db;";
-  rc = execSql(db, zSql);
+  nDb = db->nDb;
+  if( sqlite3TempInMemory(db) ){
+    zSql = "ATTACH ':memory:' AS vacuum_db;";
+  }else{
+    zSql = "ATTACH '' AS vacuum_db;";
+  }
+  rc = execSql(db, pzErrMsg, zSql);
+  if( db->nDb>nDb ){
+    pDb = &db->aDb[db->nDb-1];
+    assert( strcmp(pDb->zName,"vacuum_db")==0 );
+  }
   if( rc!=SQLITE_OK ) goto end_of_vacuum;
-  pDb = &db->aDb[db->nDb-1];
-  assert( strcmp(db->aDb[db->nDb-1].zName,"vacuum_db")==0 );
   pTemp = db->aDb[db->nDb-1].pBt;
 
+  /* The call to execSql() to attach the temp database has left the file
+  ** locked (as there was more than one active statement when the transaction
+  ** to read the schema was concluded. Unlock it here so that this doesn't
+  ** cause problems for the call to BtreeSetPageSize() below.  */
+  sqlite3BtreeCommit(pTemp);
+
   nRes = sqlite3BtreeGetReserve(pMain);
 
   /* A VACUUM cannot change the pagesize of an encrypted database. */
@@ -78452,69 +100375,78 @@ SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
   }
 #endif
 
-  if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes)
-   || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes))
-   || db->mallocFailed 
+  rc = execSql(db, pzErrMsg, "PRAGMA vacuum_db.synchronous=OFF");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Begin a transaction and take an exclusive lock on the main database
+  ** file. This is done before the sqlite3BtreeGetPageSize(pMain) call below,
+  ** to ensure that we do not try to change the page-size on a WAL database.
+  */
+  rc = execSql(db, pzErrMsg, "BEGIN;");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = sqlite3BtreeBeginTrans(pMain, 2);
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Do not attempt to change the page size for a WAL database */
+  if( sqlite3PagerGetJournalMode(sqlite3BtreePager(pMain))
+                                               ==PAGER_JOURNALMODE_WAL ){
+    db->nextPagesize = 0;
+  }
+
+  if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes, 0)
+   || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes, 0))
+   || NEVER(db->mallocFailed)
   ){
     rc = SQLITE_NOMEM;
     goto end_of_vacuum;
   }
-  rc = execSql(db, "PRAGMA vacuum_db.synchronous=OFF");
-  if( rc!=SQLITE_OK ){
-    goto end_of_vacuum;
-  }
 
 #ifndef SQLITE_OMIT_AUTOVACUUM
   sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac :
                                            sqlite3BtreeGetAutoVacuum(pMain));
 #endif
 
-  /* Begin a transaction */
-  rc = execSql(db, "BEGIN EXCLUSIVE;");
-  if( rc!=SQLITE_OK ) goto end_of_vacuum;
-
   /* Query the schema of the main database. Create a mirror schema
   ** in the temporary database.
   */
-  rc = execExecSql(db, 
+  rc = execExecSql(db, pzErrMsg,
       "SELECT 'CREATE TABLE vacuum_db.' || substr(sql,14) "
       "  FROM sqlite_master WHERE type='table' AND name!='sqlite_sequence'"
       "   AND rootpage>0"
   );
   if( rc!=SQLITE_OK ) goto end_of_vacuum;
-  rc = execExecSql(db, 
+  rc = execExecSql(db, pzErrMsg,
       "SELECT 'CREATE INDEX vacuum_db.' || substr(sql,14)"
       "  FROM sqlite_master WHERE sql LIKE 'CREATE INDEX %' ");
   if( rc!=SQLITE_OK ) goto end_of_vacuum;
-  rc = execExecSql(db, 
+  rc = execExecSql(db, pzErrMsg,
       "SELECT 'CREATE UNIQUE INDEX vacuum_db.' || substr(sql,21) "
       "  FROM sqlite_master WHERE sql LIKE 'CREATE UNIQUE INDEX %'");
   if( rc!=SQLITE_OK ) goto end_of_vacuum;
 
   /* Loop through the tables in the main database. For each, do
-  ** an "INSERT INTO vacuum_db.xxx SELECT * FROM xxx;" to copy
+  ** an "INSERT INTO vacuum_db.xxx SELECT * FROM main.xxx;" to copy
   ** the contents to the temporary database.
   */
-  rc = execExecSql(db, 
+  rc = execExecSql(db, pzErrMsg,
       "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
-      "|| ' SELECT * FROM ' || quote(name) || ';'"
-      "FROM sqlite_master "
+      "|| ' SELECT * FROM main.' || quote(name) || ';'"
+      "FROM main.sqlite_master "
       "WHERE type = 'table' AND name!='sqlite_sequence' "
       "  AND rootpage>0"
-
   );
   if( rc!=SQLITE_OK ) goto end_of_vacuum;
 
   /* Copy over the sequence table
   */
-  rc = execExecSql(db, 
+  rc = execExecSql(db, pzErrMsg,
       "SELECT 'DELETE FROM vacuum_db.' || quote(name) || ';' "
       "FROM vacuum_db.sqlite_master WHERE name='sqlite_sequence' "
   );
   if( rc!=SQLITE_OK ) goto end_of_vacuum;
-  rc = execExecSql(db, 
+  rc = execExecSql(db, pzErrMsg,
       "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
-      "|| ' SELECT * FROM ' || quote(name) || ';' "
+      "|| ' SELECT * FROM main.' || quote(name) || ';' "
       "FROM vacuum_db.sqlite_master WHERE name=='sqlite_sequence';"
   );
   if( rc!=SQLITE_OK ) goto end_of_vacuum;
@@ -78525,24 +100457,22 @@ SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
   ** associated storage, so all we have to do is copy their entries
   ** from the SQLITE_MASTER table.
   */
-  rc = execSql(db,
+  rc = execSql(db, pzErrMsg,
       "INSERT INTO vacuum_db.sqlite_master "
       "  SELECT type, name, tbl_name, rootpage, sql"
-      "    FROM sqlite_master"
+      "    FROM main.sqlite_master"
       "   WHERE type='view' OR type='trigger'"
       "      OR (type='table' AND rootpage=0)"
   );
   if( rc ) goto end_of_vacuum;
 
-  /* At this point, unless the main db was completely empty, there is now a
-  ** transaction open on the vacuum database, but not on the main database.
-  ** Open a btree level transaction on the main database. This allows a
-  ** call to sqlite3BtreeCopyFile(). The main database btree level
-  ** transaction is then committed, so the SQL level never knows it was
-  ** opened for writing. This way, the SQL transaction used to create the
-  ** temporary database never needs to be committed.
+  /* At this point, there is a write transaction open on both the 
+  ** vacuum database and the main database. Assuming no error occurs,
+  ** both transactions are closed by this block - the main database
+  ** transaction by sqlite3BtreeCopyFile() and the other by an explicit
+  ** call to sqlite3BtreeCommit().
   */
-  if( rc==SQLITE_OK ){
+  {
     u32 meta;
     int i;
 
@@ -78553,10 +100483,10 @@ SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
     ** connections to the same database will know to reread the schema.
     */
     static const unsigned char aCopy[] = {
-       1, 1,    /* Add one to the old schema cookie */
-       3, 0,    /* Preserve the default page cache size */
-       5, 0,    /* Preserve the default text encoding */
-       6, 0,    /* Preserve the user version */
+       BTREE_SCHEMA_VERSION,     1,  /* Add one to the old schema cookie */
+       BTREE_DEFAULT_CACHE_SIZE, 0,  /* Preserve the default page cache size */
+       BTREE_TEXT_ENCODING,      0,  /* Preserve the text encoding */
+       BTREE_USER_VERSION,       0,  /* Preserve the user version */
     };
 
     assert( 1==sqlite3BtreeIsInTrans(pTemp) );
@@ -78564,10 +100494,11 @@ SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
 
     /* Copy Btree meta values */
     for(i=0; i<ArraySize(aCopy); i+=2){
-      rc = sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
-      if( rc!=SQLITE_OK ) goto end_of_vacuum;
+      /* GetMeta() and UpdateMeta() cannot fail in this context because
+      ** we already have page 1 loaded into cache and marked dirty. */
+      sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
       rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]);
-      if( rc!=SQLITE_OK ) goto end_of_vacuum;
+      if( NEVER(rc!=SQLITE_OK) ) goto end_of_vacuum;
     }
 
     rc = sqlite3BtreeCopyFile(pMain, pTemp);
@@ -78577,18 +100508,18 @@ SQLITE_PRIVATE int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
 #ifndef SQLITE_OMIT_AUTOVACUUM
     sqlite3BtreeSetAutoVacuum(pMain, sqlite3BtreeGetAutoVacuum(pTemp));
 #endif
-    rc = sqlite3BtreeCommit(pMain);
   }
 
-  if( rc==SQLITE_OK ){
-    rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes);
-  }
+  assert( rc==SQLITE_OK );
+  rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes,1);
 
 end_of_vacuum:
   /* Restore the original value of db->flags */
   db->flags = saved_flags;
   db->nChange = saved_nChange;
   db->nTotalChange = saved_nTotalChange;
+  db->xTrace = saved_xTrace;
+  sqlite3BtreeSetPageSize(pMain, -1, -1, 1);
 
   /* Currently there is an SQL level transaction open on the vacuum
   ** database. No locks are held on any other files (since the main file
@@ -78605,10 +100536,13 @@ end_of_vacuum:
     pDb->pSchema = 0;
   }
 
-  sqlite3ResetInternalSchema(db, 0);
+  /* This both clears the schemas and reduces the size of the db->aDb[]
+  ** array. */ 
+  sqlite3ResetAllSchemasOfConnection(db);
 
   return rc;
 }
+
 #endif  /* SQLITE_OMIT_VACUUM && SQLITE_OMIT_ATTACH */
 
 /************** End of vacuum.c **********************************************/
@@ -78625,45 +100559,62 @@ end_of_vacuum:
 **
 *************************************************************************
 ** This file contains code used to help implement virtual tables.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 
+/*
+** Before a virtual table xCreate() or xConnect() method is invoked, the
+** sqlite3.pVtabCtx member variable is set to point to an instance of
+** this struct allocated on the stack. It is used by the implementation of 
+** the sqlite3_declare_vtab() and sqlite3_vtab_config() APIs, both of which
+** are invoked only from within xCreate and xConnect methods.
+*/
+struct VtabCtx {
+  VTable *pVTable;    /* The virtual table being constructed */
+  Table *pTab;        /* The Table object to which the virtual table belongs */
+};
+
+/*
+** The actual function that does the work of creating a new module.
+** This function implements the sqlite3_create_module() and
+** sqlite3_create_module_v2() interfaces.
+*/
 static int createModule(
   sqlite3 *db,                    /* Database in which module is registered */
   const char *zName,              /* Name assigned to this module */
   const sqlite3_module *pModule,  /* The definition of the module */
   void *pAux,                     /* Context pointer for xCreate/xConnect */
   void (*xDestroy)(void *)        /* Module destructor function */
-) {
-  int rc, nName;
-  Module *pMod;
+){
+  int rc = SQLITE_OK;
+  int nName;
 
   sqlite3_mutex_enter(db->mutex);
   nName = sqlite3Strlen30(zName);
-  pMod = (Module *)sqlite3DbMallocRaw(db, sizeof(Module) + nName + 1);
-  if( pMod ){
-    Module *pDel;
-    char *zCopy = (char *)(&pMod[1]);
-    memcpy(zCopy, zName, nName+1);
-    pMod->zName = zCopy;
-    pMod->pModule = pModule;
-    pMod->pAux = pAux;
-    pMod->xDestroy = xDestroy;
-    pDel = (Module *)sqlite3HashInsert(&db->aModule, zCopy, nName, (void*)pMod);
-    if( pDel && pDel->xDestroy ){
-      pDel->xDestroy(pDel->pAux);
+  if( sqlite3HashFind(&db->aModule, zName, nName) ){
+    rc = SQLITE_MISUSE_BKPT;
+  }else{
+    Module *pMod;
+    pMod = (Module *)sqlite3DbMallocRaw(db, sizeof(Module) + nName + 1);
+    if( pMod ){
+      Module *pDel;
+      char *zCopy = (char *)(&pMod[1]);
+      memcpy(zCopy, zName, nName+1);
+      pMod->zName = zCopy;
+      pMod->pModule = pModule;
+      pMod->pAux = pAux;
+      pMod->xDestroy = xDestroy;
+      pDel = (Module *)sqlite3HashInsert(&db->aModule,zCopy,nName,(void*)pMod);
+      assert( pDel==0 || pDel==pMod );
+      if( pDel ){
+        db->mallocFailed = 1;
+        sqlite3DbFree(db, pDel);
+      }
     }
-    sqlite3DbFree(db, pDel);
-    if( pDel==pMod ){
-      db->mallocFailed = 1;
-    }
-    sqlite3ResetInternalSchema(db, 0);
-  }else if( xDestroy ){
-    xDestroy(pAux);
   }
-  rc = sqlite3ApiExit(db, SQLITE_OK);
+  rc = sqlite3ApiExit(db, rc);
+  if( rc!=SQLITE_OK && xDestroy ) xDestroy(pAux);
+
   sqlite3_mutex_leave(db->mutex);
   return rc;
 }
@@ -78702,26 +100653,143 @@ SQLITE_API int sqlite3_create_module_v2(
 ** If a disconnect is attempted while a virtual table is locked,
 ** the disconnect is deferred until all locks have been removed.
 */
-SQLITE_PRIVATE void sqlite3VtabLock(sqlite3_vtab *pVtab){
-  pVtab->nRef++;
+SQLITE_PRIVATE void sqlite3VtabLock(VTable *pVTab){
+  pVTab->nRef++;
+}
+
+
+/*
+** pTab is a pointer to a Table structure representing a virtual-table.
+** Return a pointer to the VTable object used by connection db to access 
+** this virtual-table, if one has been created, or NULL otherwise.
+*/
+SQLITE_PRIVATE VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){
+  VTable *pVtab;
+  assert( IsVirtual(pTab) );
+  for(pVtab=pTab->pVTable; pVtab && pVtab->db!=db; pVtab=pVtab->pNext);
+  return pVtab;
 }
 
 /*
-** Unlock a virtual table.  When the last lock is removed,
-** disconnect the virtual table.
+** Decrement the ref-count on a virtual table object. When the ref-count
+** reaches zero, call the xDisconnect() method to delete the object.
 */
-SQLITE_PRIVATE void sqlite3VtabUnlock(sqlite3 *db, sqlite3_vtab *pVtab){
-  pVtab->nRef--;
-  assert(db);
-  assert( sqlite3SafetyCheckOk(db) );
-  if( pVtab->nRef==0 ){
-    if( db->magic==SQLITE_MAGIC_BUSY ){
-      (void)sqlite3SafetyOff(db);
-      pVtab->pModule->xDisconnect(pVtab);
-      (void)sqlite3SafetyOn(db);
-    } else {
-      pVtab->pModule->xDisconnect(pVtab);
+SQLITE_PRIVATE void sqlite3VtabUnlock(VTable *pVTab){
+  sqlite3 *db = pVTab->db;
+
+  assert( db );
+  assert( pVTab->nRef>0 );
+  assert( db->magic==SQLITE_MAGIC_OPEN || db->magic==SQLITE_MAGIC_ZOMBIE );
+
+  pVTab->nRef--;
+  if( pVTab->nRef==0 ){
+    sqlite3_vtab *p = pVTab->pVtab;
+    if( p ){
+      p->pModule->xDisconnect(p);
     }
+    sqlite3DbFree(db, pVTab);
+  }
+}
+
+/*
+** Table p is a virtual table. This function moves all elements in the
+** p->pVTable list to the sqlite3.pDisconnect lists of their associated
+** database connections to be disconnected at the next opportunity. 
+** Except, if argument db is not NULL, then the entry associated with
+** connection db is left in the p->pVTable list.
+*/
+static VTable *vtabDisconnectAll(sqlite3 *db, Table *p){
+  VTable *pRet = 0;
+  VTable *pVTable = p->pVTable;
+  p->pVTable = 0;
+
+  /* Assert that the mutex (if any) associated with the BtShared database 
+  ** that contains table p is held by the caller. See header comments 
+  ** above function sqlite3VtabUnlockList() for an explanation of why
+  ** this makes it safe to access the sqlite3.pDisconnect list of any
+  ** database connection that may have an entry in the p->pVTable list.
+  */
+  assert( db==0 || sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
+
+  while( pVTable ){
+    sqlite3 *db2 = pVTable->db;
+    VTable *pNext = pVTable->pNext;
+    assert( db2 );
+    if( db2==db ){
+      pRet = pVTable;
+      p->pVTable = pRet;
+      pRet->pNext = 0;
+    }else{
+      pVTable->pNext = db2->pDisconnect;
+      db2->pDisconnect = pVTable;
+    }
+    pVTable = pNext;
+  }
+
+  assert( !db || pRet );
+  return pRet;
+}
+
+/*
+** Table *p is a virtual table. This function removes the VTable object
+** for table *p associated with database connection db from the linked
+** list in p->pVTab. It also decrements the VTable ref count. This is
+** used when closing database connection db to free all of its VTable
+** objects without disturbing the rest of the Schema object (which may
+** be being used by other shared-cache connections).
+*/
+SQLITE_PRIVATE void sqlite3VtabDisconnect(sqlite3 *db, Table *p){
+  VTable **ppVTab;
+
+  assert( IsVirtual(p) );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  for(ppVTab=&p->pVTable; *ppVTab; ppVTab=&(*ppVTab)->pNext){
+    if( (*ppVTab)->db==db  ){
+      VTable *pVTab = *ppVTab;
+      *ppVTab = pVTab->pNext;
+      sqlite3VtabUnlock(pVTab);
+      break;
+    }
+  }
+}
+
+
+/*
+** Disconnect all the virtual table objects in the sqlite3.pDisconnect list.
+**
+** This function may only be called when the mutexes associated with all
+** shared b-tree databases opened using connection db are held by the 
+** caller. This is done to protect the sqlite3.pDisconnect list. The
+** sqlite3.pDisconnect list is accessed only as follows:
+**
+**   1) By this function. In this case, all BtShared mutexes and the mutex
+**      associated with the database handle itself must be held.
+**
+**   2) By function vtabDisconnectAll(), when it adds a VTable entry to
+**      the sqlite3.pDisconnect list. In this case either the BtShared mutex
+**      associated with the database the virtual table is stored in is held
+**      or, if the virtual table is stored in a non-sharable database, then
+**      the database handle mutex is held.
+**
+** As a result, a sqlite3.pDisconnect cannot be accessed simultaneously 
+** by multiple threads. It is thread-safe.
+*/
+SQLITE_PRIVATE void sqlite3VtabUnlockList(sqlite3 *db){
+  VTable *p = db->pDisconnect;
+  db->pDisconnect = 0;
+
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  if( p ){
+    sqlite3ExpirePreparedStatements(db);
+    do {
+      VTable *pNext = p->pNext;
+      sqlite3VtabUnlock(p);
+      p = pNext;
+    }while( p );
   }
 }
 
@@ -78729,15 +100797,18 @@ SQLITE_PRIVATE void sqlite3VtabUnlock(sqlite3 *db, sqlite3_vtab *pVtab){
 ** Clear any and all virtual-table information from the Table record.
 ** This routine is called, for example, just before deleting the Table
 ** record.
+**
+** Since it is a virtual-table, the Table structure contains a pointer
+** to the head of a linked list of VTable structures. Each VTable 
+** structure is associated with a single sqlite3* user of the schema.
+** The reference count of the VTable structure associated with database 
+** connection db is decremented immediately (which may lead to the 
+** structure being xDisconnected and free). Any other VTable structures
+** in the list are moved to the sqlite3.pDisconnect list of the associated 
+** database connection.
 */
-SQLITE_PRIVATE void sqlite3VtabClear(Table *p){
-  sqlite3_vtab *pVtab = p->pVtab;
-  sqlite3 *db = p->db;
-  if( pVtab ){
-    assert( p->pMod && p->pMod->pModule );
-    sqlite3VtabUnlock(db, pVtab);
-    p->pVtab = 0;
-  }
+SQLITE_PRIVATE void sqlite3VtabClear(sqlite3 *db, Table *p){
+  if( !db || db->pnBytesFreed==0 ) vtabDisconnectAll(0, p);
   if( p->azModuleArg ){
     int i;
     for(i=0; i<p->nModuleArg; i++){
@@ -78782,20 +100853,16 @@ SQLITE_PRIVATE void sqlite3VtabBeginParse(
   Parse *pParse,        /* Parsing context */
   Token *pName1,        /* Name of new table, or database name */
   Token *pName2,        /* Name of new table or NULL */
-  Token *pModuleName    /* Name of the module for the virtual table */
+  Token *pModuleName,   /* Name of the module for the virtual table */
+  int ifNotExists       /* No error if the table already exists */
 ){
   int iDb;              /* The database the table is being created in */
   Table *pTable;        /* The new virtual table */
   sqlite3 *db;          /* Database connection */
 
-  if( pParse->db->flags & SQLITE_SharedCache ){
-    sqlite3ErrorMsg(pParse, "Cannot use virtual tables in shared-cache mode");
-    return;
-  }
-
-  sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, 0);
+  sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, ifNotExists);
   pTable = pParse->pNewTable;
-  if( pTable==0 || pParse->nErr ) return;
+  if( pTable==0 ) return;
   assert( 0==pTable->pIndex );
 
   db = pParse->db;
@@ -78841,23 +100908,13 @@ static void addArgumentToVtab(Parse *pParse){
 ** has been completely parsed.
 */
 SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
-  Table *pTab;        /* The table being constructed */
-  sqlite3 *db;        /* The database connection */
-  char *zModule;      /* The module name of the table: USING modulename */
-  Module *pMod = 0;
+  Table *pTab = pParse->pNewTable;  /* The table being constructed */
+  sqlite3 *db = pParse->db;         /* The database connection */
 
+  if( pTab==0 ) return;
   addArgumentToVtab(pParse);
   pParse->sArg.z = 0;
-
-  /* Lookup the module name. */
-  pTab = pParse->pNewTable;
-  if( pTab==0 ) return;
-  db = pParse->db;
   if( pTab->nModuleArg<1 ) return;
-  zModule = pTab->azModuleArg[0];
-  pMod = (Module*)sqlite3HashFind(&db->aModule, zModule,
-                                  sqlite3Strlen30(zModule));
-  pTab->pMod = pMod;
   
   /* If the CREATE VIRTUAL TABLE statement is being entered for the
   ** first time (in other words if the virtual table is actually being
@@ -78901,28 +100958,29 @@ SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
     sqlite3ChangeCookie(pParse, iDb);
 
     sqlite3VdbeAddOp2(v, OP_Expire, 0, 0);
-    zWhere = sqlite3MPrintf(db, "name='%q'", pTab->zName);
-    sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 1, 0, zWhere, P4_DYNAMIC);
+    zWhere = sqlite3MPrintf(db, "name='%q' AND type='table'", pTab->zName);
+    sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);
     sqlite3VdbeAddOp4(v, OP_VCreate, iDb, 0, 0, 
                          pTab->zName, sqlite3Strlen30(pTab->zName) + 1);
   }
 
   /* If we are rereading the sqlite_master table create the in-memory
-  ** record of the table. If the module has already been registered,
-  ** also call the xConnect method here.
-  */
+  ** record of the table. The xConnect() method is not called until
+  ** the first time the virtual table is used in an SQL statement. This
+  ** allows a schema that contains virtual tables to be loaded before
+  ** the required virtual table implementations are registered.  */
   else {
     Table *pOld;
     Schema *pSchema = pTab->pSchema;
     const char *zName = pTab->zName;
-    int nName = sqlite3Strlen30(zName) + 1;
+    int nName = sqlite3Strlen30(zName);
+    assert( sqlite3SchemaMutexHeld(db, 0, pSchema) );
     pOld = sqlite3HashInsert(&pSchema->tblHash, zName, nName, pTab);
     if( pOld ){
       db->mallocFailed = 1;
       assert( pTab==pOld );  /* Malloc must have failed inside HashInsert() */
       return;
     }
-    pSchema->db = pParse->db;
     pParse->pNewTable = 0;
   }
 }
@@ -78964,9 +101022,9 @@ static int vtabCallConstructor(
   int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**),
   char **pzErr
 ){
+  VtabCtx sCtx, *pPriorCtx;
+  VTable *pVTable;
   int rc;
-  int rc2;
-  sqlite3_vtab *pVtab = 0;
   const char *const*azArg = (const char *const*)pTab->azModuleArg;
   int nArg = pTab->nModuleArg;
   char *zErr = 0;
@@ -78976,75 +101034,86 @@ static int vtabCallConstructor(
     return SQLITE_NOMEM;
   }
 
-  assert( !db->pVTab );
-  assert( xConstruct );
-
-  db->pVTab = pTab;
-  rc = sqlite3SafetyOff(db);
-  assert( rc==SQLITE_OK );
-  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVtab, &zErr);
-  rc2 = sqlite3SafetyOn(db);
-  if( rc==SQLITE_OK && pVtab ){
-    pVtab->pModule = pMod->pModule;
-    pVtab->nRef = 1;
-    pTab->pVtab = pVtab;
+  pVTable = sqlite3DbMallocZero(db, sizeof(VTable));
+  if( !pVTable ){
+    sqlite3DbFree(db, zModuleName);
+    return SQLITE_NOMEM;
   }
+  pVTable->db = db;
+  pVTable->pMod = pMod;
+
+  /* Invoke the virtual table constructor */
+  assert( &db->pVtabCtx );
+  assert( xConstruct );
+  sCtx.pTab = pTab;
+  sCtx.pVTable = pVTable;
+  pPriorCtx = db->pVtabCtx;
+  db->pVtabCtx = &sCtx;
+  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr);
+  db->pVtabCtx = pPriorCtx;
+  if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
 
   if( SQLITE_OK!=rc ){
     if( zErr==0 ){
       *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
     }else {
       *pzErr = sqlite3MPrintf(db, "%s", zErr);
-      sqlite3DbFree(db, zErr);
+      sqlite3_free(zErr);
     }
-  }else if( db->pVTab ){
-    const char *zFormat = "vtable constructor did not declare schema: %s";
-    *pzErr = sqlite3MPrintf(db, zFormat, pTab->zName);
-    rc = SQLITE_ERROR;
-  } 
-  if( rc==SQLITE_OK ){
-    rc = rc2;
-  }
-  db->pVTab = 0;
-  sqlite3DbFree(db, zModuleName);
+    sqlite3DbFree(db, pVTable);
+  }else if( ALWAYS(pVTable->pVtab) ){
+    /* Justification of ALWAYS():  A correct vtab constructor must allocate
+    ** the sqlite3_vtab object if successful.  */
+    pVTable->pVtab->pModule = pMod->pModule;
+    pVTable->nRef = 1;
+    if( sCtx.pTab ){
+      const char *zFormat = "vtable constructor did not declare schema: %s";
+      *pzErr = sqlite3MPrintf(db, zFormat, pTab->zName);
+      sqlite3VtabUnlock(pVTable);
+      rc = SQLITE_ERROR;
+    }else{
+      int iCol;
+      /* If everything went according to plan, link the new VTable structure
+      ** into the linked list headed by pTab->pVTable. Then loop through the 
+      ** columns of the table to see if any of them contain the token "hidden".
+      ** If so, set the Column.isHidden flag and remove the token from
+      ** the type string.  */
+      pVTable->pNext = pTab->pVTable;
+      pTab->pVTable = pVTable;
 
-  /* If everything went according to plan, loop through the columns
-  ** of the table to see if any of them contain the token "hidden".
-  ** If so, set the Column.isHidden flag and remove the token from
-  ** the type string.
-  */
-  if( rc==SQLITE_OK ){
-    int iCol;
-    for(iCol=0; iCol<pTab->nCol; iCol++){
-      char *zType = pTab->aCol[iCol].zType;
-      int nType;
-      int i = 0;
-      if( !zType ) continue;
-      nType = sqlite3Strlen30(zType);
-      if( sqlite3StrNICmp("hidden", zType, 6) || (zType[6] && zType[6]!=' ') ){
-        for(i=0; i<nType; i++){
-          if( (0==sqlite3StrNICmp(" hidden", &zType[i], 7))
-           && (zType[i+7]=='\0' || zType[i+7]==' ')
-          ){
-            i++;
-            break;
+      for(iCol=0; iCol<pTab->nCol; iCol++){
+        char *zType = pTab->aCol[iCol].zType;
+        int nType;
+        int i = 0;
+        if( !zType ) continue;
+        nType = sqlite3Strlen30(zType);
+        if( sqlite3StrNICmp("hidden", zType, 6)||(zType[6] && zType[6]!=' ') ){
+          for(i=0; i<nType; i++){
+            if( (0==sqlite3StrNICmp(" hidden", &zType[i], 7))
+             && (zType[i+7]=='\0' || zType[i+7]==' ')
+            ){
+              i++;
+              break;
+            }
           }
         }
-      }
-      if( i<nType ){
-        int j;
-        int nDel = 6 + (zType[i+6] ? 1 : 0);
-        for(j=i; (j+nDel)<=nType; j++){
-          zType[j] = zType[j+nDel];
+        if( i<nType ){
+          int j;
+          int nDel = 6 + (zType[i+6] ? 1 : 0);
+          for(j=i; (j+nDel)<=nType; j++){
+            zType[j] = zType[j+nDel];
+          }
+          if( zType[i]=='\0' && i>0 ){
+            assert(zType[i-1]==' ');
+            zType[i-1] = '\0';
+          }
+          pTab->aCol[iCol].isHidden = 1;
         }
-        if( zType[i]=='\0' && i>0 ){
-          assert(zType[i-1]==' ');
-          zType[i-1] = '\0';
-        }
-        pTab->aCol[iCol].isHidden = 1;
       }
     }
   }
+
+  sqlite3DbFree(db, zModuleName);
   return rc;
 }
 
@@ -79056,21 +101125,26 @@ static int vtabCallConstructor(
 ** This call is a no-op if table pTab is not a virtual table.
 */
 SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
+  sqlite3 *db = pParse->db;
+  const char *zMod;
   Module *pMod;
-  int rc = SQLITE_OK;
+  int rc;
 
-  if( !pTab || (pTab->tabFlags & TF_Virtual)==0 || pTab->pVtab ){
+  assert( pTab );
+  if( (pTab->tabFlags & TF_Virtual)==0 || sqlite3GetVTable(db, pTab) ){
     return SQLITE_OK;
   }
 
-  pMod = pTab->pMod;
+  /* Locate the required virtual table module */
+  zMod = pTab->azModuleArg[0];
+  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod, sqlite3Strlen30(zMod));
+
   if( !pMod ){
     const char *zModule = pTab->azModuleArg[0];
     sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
     rc = SQLITE_ERROR;
-  } else {
+  }else{
     char *zErr = 0;
-    sqlite3 *db = pParse->db;
     rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr);
     if( rc!=SQLITE_OK ){
       sqlite3ErrorMsg(pParse, "%s", zErr);
@@ -79080,16 +101154,16 @@ SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
 
   return rc;
 }
-
 /*
-** Add the virtual table pVtab to the array sqlite3.aVTrans[].
+** Grow the db->aVTrans[] array so that there is room for at least one
+** more v-table. Return SQLITE_NOMEM if a malloc fails, or SQLITE_OK otherwise.
 */
-static int addToVTrans(sqlite3 *db, sqlite3_vtab *pVtab){
+static int growVTrans(sqlite3 *db){
   const int ARRAY_INCR = 5;
 
   /* Grow the sqlite3.aVTrans array if required */
   if( (db->nVTrans%ARRAY_INCR)==0 ){
-    sqlite3_vtab **aVTrans;
+    VTable **aVTrans;
     int nBytes = sizeof(sqlite3_vtab *) * (db->nVTrans + ARRAY_INCR);
     aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes);
     if( !aVTrans ){
@@ -79099,12 +101173,19 @@ static int addToVTrans(sqlite3 *db, sqlite3_vtab *pVtab){
     db->aVTrans = aVTrans;
   }
 
-  /* Add pVtab to the end of sqlite3.aVTrans */
-  db->aVTrans[db->nVTrans++] = pVtab;
-  sqlite3VtabLock(pVtab);
   return SQLITE_OK;
 }
 
+/*
+** Add the virtual table pVTab to the array sqlite3.aVTrans[]. Space should
+** have already been reserved using growVTrans().
+*/
+static void addToVTrans(sqlite3 *db, VTable *pVTab){
+  /* Add pVtab to the end of sqlite3.aVTrans */
+  db->aVTrans[db->nVTrans++] = pVTab;
+  sqlite3VtabLock(pVTab);
+}
+
 /*
 ** This function is invoked by the vdbe to call the xCreate method
 ** of the virtual table named zTab in database iDb. 
@@ -79117,26 +101198,33 @@ SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab,
   int rc = SQLITE_OK;
   Table *pTab;
   Module *pMod;
-  const char *zModule;
+  const char *zMod;
 
   pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
-  assert(pTab && (pTab->tabFlags & TF_Virtual)!=0 && !pTab->pVtab);
-  pMod = pTab->pMod;
-  zModule = pTab->azModuleArg[0];
+  assert( pTab && (pTab->tabFlags & TF_Virtual)!=0 && !pTab->pVTable );
+
+  /* Locate the required virtual table module */
+  zMod = pTab->azModuleArg[0];
+  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod, sqlite3Strlen30(zMod));
 
   /* If the module has been registered and includes a Create method, 
   ** invoke it now. If the module has not been registered, return an 
   ** error. Otherwise, do nothing.
   */
   if( !pMod ){
-    *pzErr = sqlite3MPrintf(db, "no such module: %s", zModule);
+    *pzErr = sqlite3MPrintf(db, "no such module: %s", zMod);
     rc = SQLITE_ERROR;
   }else{
     rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
   }
 
-  if( rc==SQLITE_OK && pTab->pVtab ){
-      rc = addToVTrans(db, pTab->pVtab);
+  /* Justification of ALWAYS():  The xConstructor method is required to
+  ** create a valid sqlite3_vtab if it returns SQLITE_OK. */
+  if( rc==SQLITE_OK && ALWAYS(sqlite3GetVTable(db, pTab)) ){
+    rc = growVTrans(db);
+    if( rc==SQLITE_OK ){
+      addToVTrans(db, sqlite3GetVTable(db, pTab));
+    }
   }
 
   return rc;
@@ -79148,46 +101236,54 @@ SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab,
 ** virtual table module.
 */
 SQLITE_API int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
-  Parse sParse;
+  Parse *pParse;
 
   int rc = SQLITE_OK;
   Table *pTab;
   char *zErr = 0;
 
   sqlite3_mutex_enter(db->mutex);
-  pTab = db->pVTab;
-  if( !pTab ){
+  if( !db->pVtabCtx || !(pTab = db->pVtabCtx->pTab) ){
     sqlite3Error(db, SQLITE_MISUSE, 0);
     sqlite3_mutex_leave(db->mutex);
-    return SQLITE_MISUSE;
+    return SQLITE_MISUSE_BKPT;
   }
-  assert((pTab->tabFlags & TF_Virtual)!=0 && pTab->nCol==0 && pTab->aCol==0);
+  assert( (pTab->tabFlags & TF_Virtual)!=0 );
 
-  memset(&sParse, 0, sizeof(Parse));
-  sParse.declareVtab = 1;
-  sParse.db = db;
-
-  if( 
-      SQLITE_OK == sqlite3RunParser(&sParse, zCreateTable, &zErr) && 
-      sParse.pNewTable && 
-      !sParse.pNewTable->pSelect && 
-      (sParse.pNewTable->tabFlags & TF_Virtual)==0
-  ){
-    pTab->aCol = sParse.pNewTable->aCol;
-    pTab->nCol = sParse.pNewTable->nCol;
-    sParse.pNewTable->nCol = 0;
-    sParse.pNewTable->aCol = 0;
-    db->pVTab = 0;
-  } else {
-    sqlite3Error(db, SQLITE_ERROR, zErr);
-    sqlite3DbFree(db, zErr);
-    rc = SQLITE_ERROR;
+  pParse = sqlite3StackAllocZero(db, sizeof(*pParse));
+  if( pParse==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    pParse->declareVtab = 1;
+    pParse->db = db;
+    pParse->nQueryLoop = 1;
+  
+    if( SQLITE_OK==sqlite3RunParser(pParse, zCreateTable, &zErr) 
+     && pParse->pNewTable
+     && !db->mallocFailed
+     && !pParse->pNewTable->pSelect
+     && (pParse->pNewTable->tabFlags & TF_Virtual)==0
+    ){
+      if( !pTab->aCol ){
+        pTab->aCol = pParse->pNewTable->aCol;
+        pTab->nCol = pParse->pNewTable->nCol;
+        pParse->pNewTable->nCol = 0;
+        pParse->pNewTable->aCol = 0;
+      }
+      db->pVtabCtx->pTab = 0;
+    }else{
+      sqlite3Error(db, SQLITE_ERROR, (zErr ? "%s" : 0), zErr);
+      sqlite3DbFree(db, zErr);
+      rc = SQLITE_ERROR;
+    }
+    pParse->declareVtab = 0;
+  
+    if( pParse->pVdbe ){
+      sqlite3VdbeFinalize(pParse->pVdbe);
+    }
+    sqlite3DeleteTable(db, pParse->pNewTable);
+    sqlite3StackFree(db, pParse);
   }
-  sParse.declareVtab = 0;
-
-  sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
-  sqlite3DeleteTable(sParse.pNewTable);
-  sParse.pNewTable = 0;
 
   assert( (rc&0xff)==rc );
   rc = sqlite3ApiExit(db, rc);
@@ -79202,30 +101298,23 @@ SQLITE_API int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
 **
 ** This call is a no-op if zTab is not a virtual table.
 */
-SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab)
-{
+SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){
   int rc = SQLITE_OK;
   Table *pTab;
 
   pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
-  assert(pTab);
-  if( pTab->pVtab ){
-    int (*xDestroy)(sqlite3_vtab *pVTab) = pTab->pMod->pModule->xDestroy;
-    rc = sqlite3SafetyOff(db);
+  if( ALWAYS(pTab!=0 && pTab->pVTable!=0) ){
+    VTable *p = vtabDisconnectAll(db, pTab);
+
     assert( rc==SQLITE_OK );
-    if( xDestroy ){
-      rc = xDestroy(pTab->pVtab);
-    }
-    (void)sqlite3SafetyOn(db);
+    rc = p->pMod->pModule->xDestroy(p->pVtab);
+
+    /* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */
     if( rc==SQLITE_OK ){
-      int i;
-      for(i=0; i<db->nVTrans; i++){
-        if( db->aVTrans[i]==pTab->pVtab ){
-          db->aVTrans[i] = db->aVTrans[--db->nVTrans];
-          break;
-        }
-      }
-      pTab->pVtab = 0;
+      assert( pTab->pVTable==p && p->pNext==0 );
+      p->pVtab = 0;
+      pTab->pVTable = 0;
+      sqlite3VtabUnlock(p);
     }
   }
 
@@ -79243,12 +101332,16 @@ SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab
 static void callFinaliser(sqlite3 *db, int offset){
   int i;
   if( db->aVTrans ){
-    for(i=0; i<db->nVTrans && db->aVTrans[i]; i++){
-      sqlite3_vtab *pVtab = db->aVTrans[i];
-      int (*x)(sqlite3_vtab *);
-      x = *(int (**)(sqlite3_vtab *))((char *)pVtab->pModule + offset);
-      if( x ) x(pVtab);
-      sqlite3VtabUnlock(db, pVtab);
+    for(i=0; i<db->nVTrans; i++){
+      VTable *pVTab = db->aVTrans[i];
+      sqlite3_vtab *p = pVTab->pVtab;
+      if( p ){
+        int (*x)(sqlite3_vtab *);
+        x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
+        if( x ) x(p);
+      }
+      pVTab->iSavepoint = 0;
+      sqlite3VtabUnlock(pVTab);
     }
     sqlite3DbFree(db, db->aVTrans);
     db->nVTrans = 0;
@@ -79267,28 +101360,20 @@ static void callFinaliser(sqlite3 *db, int offset){
 SQLITE_PRIVATE int sqlite3VtabSync(sqlite3 *db, char **pzErrmsg){
   int i;
   int rc = SQLITE_OK;
-  int rcsafety;
-  sqlite3_vtab **aVTrans = db->aVTrans;
+  VTable **aVTrans = db->aVTrans;
 
-  rc = sqlite3SafetyOff(db);
   db->aVTrans = 0;
-  for(i=0; rc==SQLITE_OK && i<db->nVTrans && aVTrans[i]; i++){
-    sqlite3_vtab *pVtab = aVTrans[i];
+  for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
     int (*x)(sqlite3_vtab *);
-    x = pVtab->pModule->xSync;
-    if( x ){
+    sqlite3_vtab *pVtab = aVTrans[i]->pVtab;
+    if( pVtab && (x = pVtab->pModule->xSync)!=0 ){
       rc = x(pVtab);
       sqlite3DbFree(db, *pzErrmsg);
-      *pzErrmsg = pVtab->zErrMsg;
-      pVtab->zErrMsg = 0;
+      *pzErrmsg = sqlite3DbStrDup(db, pVtab->zErrMsg);
+      sqlite3_free(pVtab->zErrMsg);
     }
   }
   db->aVTrans = aVTrans;
-  rcsafety = sqlite3SafetyOn(db);
-
-  if( rc==SQLITE_OK ){
-    rc = rcsafety;
-  }
   return rc;
 }
 
@@ -79318,7 +101403,7 @@ SQLITE_PRIVATE int sqlite3VtabCommit(sqlite3 *db){
 ** If the xBegin call is successful, place the sqlite3_vtab pointer
 ** in the sqlite3.aVTrans array.
 */
-SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *db, sqlite3_vtab *pVtab){
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *db, VTable *pVTab){
   int rc = SQLITE_OK;
   const sqlite3_module *pModule;
 
@@ -79330,26 +101415,77 @@ SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *db, sqlite3_vtab *pVtab){
   if( sqlite3VtabInSync(db) ){
     return SQLITE_LOCKED;
   }
-  if( !pVtab ){
+  if( !pVTab ){
     return SQLITE_OK;
   } 
-  pModule = pVtab->pModule;
+  pModule = pVTab->pVtab->pModule;
 
   if( pModule->xBegin ){
     int i;
 
-
     /* If pVtab is already in the aVTrans array, return early */
-    for(i=0; (i<db->nVTrans) && 0!=db->aVTrans[i]; i++){
-      if( db->aVTrans[i]==pVtab ){
+    for(i=0; i<db->nVTrans; i++){
+      if( db->aVTrans[i]==pVTab ){
         return SQLITE_OK;
       }
     }
 
-    /* Invoke the xBegin method */
-    rc = pModule->xBegin(pVtab);
+    /* Invoke the xBegin method. If successful, add the vtab to the 
+    ** sqlite3.aVTrans[] array. */
+    rc = growVTrans(db);
     if( rc==SQLITE_OK ){
-      rc = addToVTrans(db, pVtab);
+      rc = pModule->xBegin(pVTab->pVtab);
+      if( rc==SQLITE_OK ){
+        addToVTrans(db, pVTab);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Invoke either the xSavepoint, xRollbackTo or xRelease method of all
+** virtual tables that currently have an open transaction. Pass iSavepoint
+** as the second argument to the virtual table method invoked.
+**
+** If op is SAVEPOINT_BEGIN, the xSavepoint method is invoked. If it is
+** SAVEPOINT_ROLLBACK, the xRollbackTo method. Otherwise, if op is 
+** SAVEPOINT_RELEASE, then the xRelease method of each virtual table with
+** an open transaction is invoked.
+**
+** If any virtual table method returns an error code other than SQLITE_OK, 
+** processing is abandoned and the error returned to the caller of this
+** function immediately. If all calls to virtual table methods are successful,
+** SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3VtabSavepoint(sqlite3 *db, int op, int iSavepoint){
+  int rc = SQLITE_OK;
+
+  assert( op==SAVEPOINT_RELEASE||op==SAVEPOINT_ROLLBACK||op==SAVEPOINT_BEGIN );
+  assert( iSavepoint>=0 );
+  if( db->aVTrans ){
+    int i;
+    for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
+      VTable *pVTab = db->aVTrans[i];
+      const sqlite3_module *pMod = pVTab->pMod->pModule;
+      if( pVTab->pVtab && pMod->iVersion>=2 ){
+        int (*xMethod)(sqlite3_vtab *, int);
+        switch( op ){
+          case SAVEPOINT_BEGIN:
+            xMethod = pMod->xSavepoint;
+            pVTab->iSavepoint = iSavepoint+1;
+            break;
+          case SAVEPOINT_ROLLBACK:
+            xMethod = pMod->xRollbackTo;
+            break;
+          default:
+            xMethod = pMod->xRelease;
+            break;
+        }
+        if( xMethod && pVTab->iSavepoint>iSavepoint ){
+          rc = xMethod(pVTab->pVtab, iSavepoint);
+        }
+      }
     }
   }
   return rc;
@@ -79386,12 +101522,12 @@ SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(
 
 
   /* Check to see the left operand is a column in a virtual table */
-  if( pExpr==0 ) return pDef;
+  if( NEVER(pExpr==0) ) return pDef;
   if( pExpr->op!=TK_COLUMN ) return pDef;
   pTab = pExpr->pTab;
-  if( pTab==0 ) return pDef;
+  if( NEVER(pTab==0) ) return pDef;
   if( (pTab->tabFlags & TF_Virtual)==0 ) return pDef;
-  pVtab = pTab->pVtab;
+  pVtab = sqlite3GetVTable(db, pTab)->pVtab;
   assert( pVtab!=0 );
   assert( pVtab->pModule!=0 );
   pMod = (sqlite3_module *)pVtab->pModule;
@@ -79407,11 +101543,6 @@ SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(
     }
     rc = pMod->xFindFunction(pVtab, nArg, zLowerName, &xFunc, &pArg);
     sqlite3DbFree(db, zLowerName);
-    if( pVtab->zErrMsg ){
-      sqlite3Error(db, rc, "%s", pVtab->zErrMsg);
-      sqlite3DbFree(db, pVtab->zErrMsg);
-      pVtab->zErrMsg = 0;
-    }
   }
   if( rc==0 ){
     return pDef;
@@ -79420,7 +101551,7 @@ SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(
   /* Create a new ephemeral function definition for the overloaded
   ** function */
   pNew = sqlite3DbMallocZero(db, sizeof(*pNew)
-                             + sqlite3Strlen30(pDef->zName) );
+                             + sqlite3Strlen30(pDef->zName) + 1);
   if( pNew==0 ){
     return pDef;
   }
@@ -79440,20 +101571,75 @@ SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(
 ** is a no-op.
 */
 SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
   int i, n;
+  Table **apVtabLock;
+
   assert( IsVirtual(pTab) );
-  for(i=0; i<pParse->nVtabLock; i++){
-    if( pTab==pParse->apVtabLock[i] ) return;
+  for(i=0; i<pToplevel->nVtabLock; i++){
+    if( pTab==pToplevel->apVtabLock[i] ) return;
   }
-  n = (pParse->nVtabLock+1)*sizeof(pParse->apVtabLock[0]);
-  pParse->apVtabLock = sqlite3_realloc(pParse->apVtabLock, n);
-  if( pParse->apVtabLock ){
-    pParse->apVtabLock[pParse->nVtabLock++] = pTab;
+  n = (pToplevel->nVtabLock+1)*sizeof(pToplevel->apVtabLock[0]);
+  apVtabLock = sqlite3_realloc(pToplevel->apVtabLock, n);
+  if( apVtabLock ){
+    pToplevel->apVtabLock = apVtabLock;
+    pToplevel->apVtabLock[pToplevel->nVtabLock++] = pTab;
   }else{
-    pParse->db->mallocFailed = 1;
+    pToplevel->db->mallocFailed = 1;
   }
 }
 
+/*
+** Return the ON CONFLICT resolution mode in effect for the virtual
+** table update operation currently in progress.
+**
+** The results of this routine are undefined unless it is called from
+** within an xUpdate method.
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *db){
+  static const unsigned char aMap[] = { 
+    SQLITE_ROLLBACK, SQLITE_ABORT, SQLITE_FAIL, SQLITE_IGNORE, SQLITE_REPLACE 
+  };
+  assert( OE_Rollback==1 && OE_Abort==2 && OE_Fail==3 );
+  assert( OE_Ignore==4 && OE_Replace==5 );
+  assert( db->vtabOnConflict>=1 && db->vtabOnConflict<=5 );
+  return (int)aMap[db->vtabOnConflict-1];
+}
+
+/*
+** Call from within the xCreate() or xConnect() methods to provide 
+** the SQLite core with additional information about the behavior
+** of the virtual table being implemented.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3 *db, int op, ...){
+  va_list ap;
+  int rc = SQLITE_OK;
+
+  sqlite3_mutex_enter(db->mutex);
+
+  va_start(ap, op);
+  switch( op ){
+    case SQLITE_VTAB_CONSTRAINT_SUPPORT: {
+      VtabCtx *p = db->pVtabCtx;
+      if( !p ){
+        rc = SQLITE_MISUSE_BKPT;
+      }else{
+        assert( p->pTab==0 || (p->pTab->tabFlags & TF_Virtual)!=0 );
+        p->pVTable->bConstraint = (u8)va_arg(ap, int);
+      }
+      break;
+    }
+    default:
+      rc = SQLITE_MISUSE_BKPT;
+      break;
+  }
+  va_end(ap);
+
+  if( rc!=SQLITE_OK ) sqlite3Error(db, rc, 0);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
 /************** End of vtab.c ************************************************/
@@ -79475,17 +101661,16 @@ SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
 ** rows.  Indices are selected and used to speed the search when doing
 ** so is applicable.  Because this module is responsible for selecting
 ** indices, you might also think of this module as the "query optimizer".
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
+
 /*
 ** Trace output macros
 */
 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
 SQLITE_PRIVATE int sqlite3WhereTrace = 0;
 #endif
-#if 0
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
 # define WHERETRACE(X)  if(sqlite3WhereTrace) sqlite3DebugPrintf X
 #else
 # define WHERETRACE(X)
@@ -79502,10 +101687,8 @@ typedef struct WhereCost WhereCost;
 /*
 ** The query generator uses an array of instances of this structure to
 ** help it analyze the subexpressions of the WHERE clause.  Each WHERE
-** clause subexpression is separated from the others by AND operators.
-** (Note: the same data structure is also reused to hold a group of terms
-** separated by OR operators.  But at the top-level, everything is AND
-** separated.)
+** clause subexpression is separated from the others by AND operators,
+** usually, or sometimes subexpressions separated by OR.
 **
 ** All WhereTerms are collected into a single WhereClause structure.  
 ** The following identity holds:
@@ -79580,19 +101763,39 @@ struct WhereTerm {
 #define TERM_ORINFO     0x10   /* Need to free the WhereTerm.u.pOrInfo object */
 #define TERM_ANDINFO    0x20   /* Need to free the WhereTerm.u.pAndInfo obj */
 #define TERM_OR_OK      0x40   /* Used during OR-clause processing */
+#ifdef SQLITE_ENABLE_STAT3
+#  define TERM_VNULL    0x80   /* Manufactured x>NULL or x<=NULL term */
+#else
+#  define TERM_VNULL    0x00   /* Disabled if not using stat3 */
+#endif
 
 /*
 ** An instance of the following structure holds all information about a
 ** WHERE clause.  Mostly this is a container for one or more WhereTerms.
+**
+** Explanation of pOuter:  For a WHERE clause of the form
+**
+**           a AND ((b AND c) OR (d AND e)) AND f
+**
+** There are separate WhereClause objects for the whole clause and for
+** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
+** subclauses points to the WhereClause object for the whole clause.
 */
 struct WhereClause {
   Parse *pParse;           /* The parser context */
   WhereMaskSet *pMaskSet;  /* Mapping of table cursor numbers to bitmasks */
+  Bitmask vmask;           /* Bitmask identifying virtual table cursors */
+  WhereClause *pOuter;     /* Outer conjunction */
   u8 op;                   /* Split operator.  TK_AND or TK_OR */
+  u16 wctrlFlags;          /* Might include WHERE_AND_ONLY */
   int nTerm;               /* Number of terms */
   int nSlot;               /* Number of entries in a[] */
   WhereTerm *a;            /* Each a[] describes a term of the WHERE cluase */
-  WhereTerm aStatic[4];    /* Initial static space for a[] */
+#if defined(SQLITE_SMALL_STACK)
+  WhereTerm aStatic[1];    /* Initial static space for a[] */
+#else
+  WhereTerm aStatic[8];    /* Initial static space for a[] */
+#endif
 };
 
 /*
@@ -79650,7 +101853,7 @@ struct WhereMaskSet {
 struct WhereCost {
   WherePlan plan;    /* The lookup strategy */
   double rCost;      /* Overall cost of pursuing this search strategy */
-  double nRow;       /* Estimated number of output rows */
+  Bitmask used;      /* Bitmask of cursors used by this plan */
 };
 
 /*
@@ -79668,6 +101871,7 @@ struct WhereCost {
 #define WO_ISNULL 0x080
 #define WO_OR     0x100       /* Two or more OR-connected terms */
 #define WO_AND    0x200       /* Two or more AND-connected terms */
+#define WO_NOOP   0x800       /* This term does not restrict search space */
 
 #define WO_ALL    0xfff       /* Mask of all possible WO_* values */
 #define WO_SINGLE 0x0ff       /* Mask of all non-compound WO_* values */
@@ -79687,19 +101891,24 @@ struct WhereCost {
 */
 #define WHERE_ROWID_EQ     0x00001000  /* rowid=EXPR or rowid IN (...) */
 #define WHERE_ROWID_RANGE  0x00002000  /* rowid<EXPR and/or rowid>EXPR */
-#define WHERE_COLUMN_EQ    0x00010000  /* x=EXPR or x IN (...) */
+#define WHERE_COLUMN_EQ    0x00010000  /* x=EXPR or x IN (...) or x IS NULL */
 #define WHERE_COLUMN_RANGE 0x00020000  /* x<EXPR and/or x>EXPR */
 #define WHERE_COLUMN_IN    0x00040000  /* x IN (...) */
-#define WHERE_INDEXED      0x00070000  /* Anything that uses an index */
-#define WHERE_IN_ABLE      0x00071000  /* Able to support an IN operator */
+#define WHERE_COLUMN_NULL  0x00080000  /* x IS NULL */
+#define WHERE_INDEXED      0x000f0000  /* Anything that uses an index */
+#define WHERE_NOT_FULLSCAN 0x100f3000  /* Does not do a full table scan */
+#define WHERE_IN_ABLE      0x000f1000  /* Able to support an IN operator */
 #define WHERE_TOP_LIMIT    0x00100000  /* x<EXPR or x<=EXPR constraint */
 #define WHERE_BTM_LIMIT    0x00200000  /* x>EXPR or x>=EXPR constraint */
+#define WHERE_BOTH_LIMIT   0x00300000  /* Both x>EXPR and x<EXPR */
 #define WHERE_IDX_ONLY     0x00800000  /* Use index only - omit table */
 #define WHERE_ORDERBY      0x01000000  /* Output will appear in correct order */
 #define WHERE_REVERSE      0x02000000  /* Scan in reverse order */
 #define WHERE_UNIQUE       0x04000000  /* Selects no more than one row */
 #define WHERE_VIRTUALTABLE 0x08000000  /* Use virtual-table processing */
 #define WHERE_MULTI_OR     0x10000000  /* OR using multiple indices */
+#define WHERE_TEMP_INDEX   0x20000000  /* Uses an ephemeral index */
+#define WHERE_DISTINCT     0x40000000  /* Correct order for DISTINCT */
 
 /*
 ** Initialize a preallocated WhereClause structure.
@@ -79707,13 +101916,17 @@ struct WhereCost {
 static void whereClauseInit(
   WhereClause *pWC,        /* The WhereClause to be initialized */
   Parse *pParse,           /* The parsing context */
-  WhereMaskSet *pMaskSet   /* Mapping from table cursor numbers to bitmasks */
+  WhereMaskSet *pMaskSet,  /* Mapping from table cursor numbers to bitmasks */
+  u16 wctrlFlags           /* Might include WHERE_AND_ONLY */
 ){
   pWC->pParse = pParse;
   pWC->pMaskSet = pMaskSet;
+  pWC->pOuter = 0;
   pWC->nTerm = 0;
   pWC->nSlot = ArraySize(pWC->aStatic);
   pWC->a = pWC->aStatic;
+  pWC->vmask = 0;
+  pWC->wctrlFlags = wctrlFlags;
 }
 
 /* Forward reference */
@@ -79780,6 +101993,7 @@ static void whereClauseClear(WhereClause *pWC){
 static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){
   WhereTerm *pTerm;
   int idx;
+  testcase( wtFlags & TERM_VIRTUAL );  /* EV: R-00211-15100 */
   if( pWC->nTerm>=pWC->nSlot ){
     WhereTerm *pOld = pWC->a;
     sqlite3 *db = pWC->pParse->db;
@@ -79834,7 +102048,7 @@ static void whereSplit(WhereClause *pWC, Expr *pExpr, int op){
 }
 
 /*
-** Initialize an expression mask set
+** Initialize an expression mask set (a WhereMaskSet object)
 */
 #define initMaskSet(P)  memset(P, 0, sizeof(*P))
 
@@ -79844,6 +102058,7 @@ static void whereSplit(WhereClause *pWC, Expr *pExpr, int op){
 */
 static Bitmask getMask(WhereMaskSet *pMaskSet, int iCursor){
   int i;
+  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
   for(i=0; i<pMaskSet->n; i++){
     if( pMaskSet->ix[i]==iCursor ){
       return ((Bitmask)1)<<i;
@@ -79890,8 +102105,11 @@ static Bitmask exprTableUsage(WhereMaskSet *pMaskSet, Expr *p){
   }
   mask = exprTableUsage(pMaskSet, p->pRight);
   mask |= exprTableUsage(pMaskSet, p->pLeft);
-  mask |= exprListTableUsage(pMaskSet, p->pList);
-  mask |= exprSelectTableUsage(pMaskSet, p->pSelect);
+  if( ExprHasProperty(p, EP_xIsSelect) ){
+    mask |= exprSelectTableUsage(pMaskSet, p->x.pSelect);
+  }else{
+    mask |= exprListTableUsage(pMaskSet, p->x.pList);
+  }
   return mask;
 }
 static Bitmask exprListTableUsage(WhereMaskSet *pMaskSet, ExprList *pList){
@@ -79907,11 +102125,19 @@ static Bitmask exprListTableUsage(WhereMaskSet *pMaskSet, ExprList *pList){
 static Bitmask exprSelectTableUsage(WhereMaskSet *pMaskSet, Select *pS){
   Bitmask mask = 0;
   while( pS ){
+    SrcList *pSrc = pS->pSrc;
     mask |= exprListTableUsage(pMaskSet, pS->pEList);
     mask |= exprListTableUsage(pMaskSet, pS->pGroupBy);
     mask |= exprListTableUsage(pMaskSet, pS->pOrderBy);
     mask |= exprTableUsage(pMaskSet, pS->pWhere);
     mask |= exprTableUsage(pMaskSet, pS->pHaving);
+    if( ALWAYS(pSrc!=0) ){
+      int i;
+      for(i=0; i<pSrc->nSrc; i++){
+        mask |= exprSelectTableUsage(pMaskSet, pSrc->a[i].pSelect);
+        mask |= exprTableUsage(pMaskSet, pSrc->a[i].pOn);
+      }
+    }
     pS = pS->pPrior;
   }
   return mask;
@@ -79921,6 +102147,13 @@ static Bitmask exprSelectTableUsage(WhereMaskSet *pMaskSet, Select *pS){
 ** Return TRUE if the given operator is one of the operators that is
 ** allowed for an indexable WHERE clause term.  The allowed operators are
 ** "=", "<", ">", "<=", ">=", and "IN".
+**
+** IMPLEMENTATION-OF: R-59926-26393 To be usable by an index a term must be
+** of one of the following forms: column = expression column > expression
+** column >= expression column < expression column <= expression
+** expression = column expression > column expression >= column
+** expression < column expression <= column column IN
+** (expression-list) column IN (subquery) column IS NULL
 */
 static int allowedOp(int op){
   assert( TK_GT>TK_EQ && TK_GT<TK_GE );
@@ -80009,36 +102242,38 @@ static WhereTerm *findTerm(
   int k;
   assert( iCur>=0 );
   op &= WO_ALL;
-  for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
-    if( pTerm->leftCursor==iCur
-       && (pTerm->prereqRight & notReady)==0
-       && pTerm->u.leftColumn==iColumn
-       && (pTerm->eOperator & op)!=0
-    ){
-      if( pIdx && pTerm->eOperator!=WO_ISNULL ){
-        Expr *pX = pTerm->pExpr;
-        CollSeq *pColl;
-        char idxaff;
-        int j;
-        Parse *pParse = pWC->pParse;
-
-        idxaff = pIdx->pTable->aCol[iColumn].affinity;
-        if( !sqlite3IndexAffinityOk(pX, idxaff) ) continue;
-
-        /* Figure out the collation sequence required from an index for
-        ** it to be useful for optimising expression pX. Store this
-        ** value in variable pColl.
-        */
-        assert(pX->pLeft);
-        pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
-        assert(pColl || pParse->nErr);
-
-        for(j=0; pIdx->aiColumn[j]!=iColumn; j++){
-          if( NEVER(j>=pIdx->nColumn) ) return 0;
+  for(; pWC; pWC=pWC->pOuter){
+    for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
+      if( pTerm->leftCursor==iCur
+         && (pTerm->prereqRight & notReady)==0
+         && pTerm->u.leftColumn==iColumn
+         && (pTerm->eOperator & op)!=0
+      ){
+        if( iColumn>=0 && pIdx && pTerm->eOperator!=WO_ISNULL ){
+          Expr *pX = pTerm->pExpr;
+          CollSeq *pColl;
+          char idxaff;
+          int j;
+          Parse *pParse = pWC->pParse;
+  
+          idxaff = pIdx->pTable->aCol[iColumn].affinity;
+          if( !sqlite3IndexAffinityOk(pX, idxaff) ) continue;
+  
+          /* Figure out the collation sequence required from an index for
+          ** it to be useful for optimising expression pX. Store this
+          ** value in variable pColl.
+          */
+          assert(pX->pLeft);
+          pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
+          assert(pColl || pParse->nErr);
+  
+          for(j=0; pIdx->aiColumn[j]!=iColumn; j++){
+            if( NEVER(j>=pIdx->nColumn) ) return 0;
+          }
+          if( pColl && sqlite3StrICmp(pColl->zName, pIdx->azColl[j]) ) continue;
         }
-        if( pColl && sqlite3StrICmp(pColl->zName, pIdx->azColl[j]) ) continue;
+        return pTerm;
       }
-      return pTerm;
     }
   }
   return 0;
@@ -80074,18 +102309,19 @@ static void exprAnalyzeAll(
 static int isLikeOrGlob(
   Parse *pParse,    /* Parsing and code generating context */
   Expr *pExpr,      /* Test this expression */
-  int *pnPattern,   /* Number of non-wildcard prefix characters */
+  Expr **ppPrefix,  /* Pointer to TK_STRING expression with pattern prefix */
   int *pisComplete, /* True if the only wildcard is % in the last character */
   int *pnoCase      /* True if uppercase is equivalent to lowercase */
 ){
-  const char *z;             /* String on RHS of LIKE operator */
+  const char *z = 0;         /* String on RHS of LIKE operator */
   Expr *pRight, *pLeft;      /* Right and left size of LIKE operator */
   ExprList *pList;           /* List of operands to the LIKE operator */
   int c;                     /* One character in z[] */
   int cnt;                   /* Number of non-wildcard prefix characters */
   char wc[3];                /* Wildcard characters */
-  CollSeq *pColl;            /* Collating sequence for LHS */
   sqlite3 *db = pParse->db;  /* Database connection */
+  sqlite3_value *pVal = 0;
+  int op;                    /* Opcode of pRight */
 
   if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, wc) ){
     return 0;
@@ -80093,37 +102329,69 @@ static int isLikeOrGlob(
 #ifdef SQLITE_EBCDIC
   if( *pnoCase ) return 0;
 #endif
-  pList = pExpr->pList;
-  pRight = pList->a[0].pExpr;
-  if( pRight->op!=TK_STRING ){
-    return 0;
-  }
+  pList = pExpr->x.pList;
   pLeft = pList->a[1].pExpr;
-  if( pLeft->op!=TK_COLUMN ){
+  if( pLeft->op!=TK_COLUMN 
+   || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT 
+   || IsVirtual(pLeft->pTab)
+  ){
+    /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
+    ** be the name of an indexed column with TEXT affinity. */
     return 0;
   }
-  pColl = sqlite3ExprCollSeq(pParse, pLeft);
-  assert( pColl!=0 || pLeft->iColumn==-1 );
-  if( pColl==0 ){
-    /* No collation is defined for the ROWID.  Use the default. */
-    pColl = db->pDfltColl;
+  assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */
+
+  pRight = pList->a[0].pExpr;
+  op = pRight->op;
+  if( op==TK_REGISTER ){
+    op = pRight->op2;
   }
-  if( (pColl->type!=SQLITE_COLL_BINARY || *pnoCase) &&
-      (pColl->type!=SQLITE_COLL_NOCASE || !*pnoCase) ){
-    return 0;
+  if( op==TK_VARIABLE ){
+    Vdbe *pReprepare = pParse->pReprepare;
+    int iCol = pRight->iColumn;
+    pVal = sqlite3VdbeGetValue(pReprepare, iCol, SQLITE_AFF_NONE);
+    if( pVal && sqlite3_value_type(pVal)==SQLITE_TEXT ){
+      z = (char *)sqlite3_value_text(pVal);
+    }
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iCol);
+    assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
+  }else if( op==TK_STRING ){
+    z = pRight->u.zToken;
   }
-  sqlite3DequoteExpr(db, pRight);
-  z = (char *)pRight->token.z;
-  cnt = 0;
   if( z ){
-    while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){ cnt++; }
+    cnt = 0;
+    while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){
+      cnt++;
+    }
+    if( cnt!=0 && 255!=(u8)z[cnt-1] ){
+      Expr *pPrefix;
+      *pisComplete = c==wc[0] && z[cnt+1]==0;
+      pPrefix = sqlite3Expr(db, TK_STRING, z);
+      if( pPrefix ) pPrefix->u.zToken[cnt] = 0;
+      *ppPrefix = pPrefix;
+      if( op==TK_VARIABLE ){
+        Vdbe *v = pParse->pVdbe;
+        sqlite3VdbeSetVarmask(v, pRight->iColumn);
+        if( *pisComplete && pRight->u.zToken[1] ){
+          /* If the rhs of the LIKE expression is a variable, and the current
+          ** value of the variable means there is no need to invoke the LIKE
+          ** function, then no OP_Variable will be added to the program.
+          ** This causes problems for the sqlite3_bind_parameter_name()
+          ** API. To workaround them, add a dummy OP_Variable here.
+          */ 
+          int r1 = sqlite3GetTempReg(pParse);
+          sqlite3ExprCodeTarget(pParse, pRight, r1);
+          sqlite3VdbeChangeP3(v, sqlite3VdbeCurrentAddr(v)-1, 0);
+          sqlite3ReleaseTempReg(pParse, r1);
+        }
+      }
+    }else{
+      z = 0;
+    }
   }
-  if( cnt==0 || 255==(u8)z[cnt-1] ){
-    return 0;
-  }
-  *pisComplete = z[cnt]==wc[0] && z[cnt+1]==0;
-  *pnPattern = cnt;
-  return 1;
+
+  sqlite3ValueFree(pVal);
+  return (z!=0);
 }
 #endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
 
@@ -80144,11 +102412,10 @@ static int isMatchOfColumn(
   if( pExpr->op!=TK_FUNCTION ){
     return 0;
   }
-  if( pExpr->token.n!=5 ||
-       sqlite3StrNICmp((const char*)pExpr->token.z,"match",5)!=0 ){
+  if( sqlite3StrICmp(pExpr->u.zToken,"match")!=0 ){
     return 0;
   }
-  pList = pExpr->pList;
+  pList = pExpr->x.pList;
   if( pList->nExpr!=2 ){
     return 0;
   }
@@ -80273,7 +102540,7 @@ static void exprAnalyzeOrTerm(
   if( pOrInfo==0 ) return;
   pTerm->wtFlags |= TERM_ORINFO;
   pOrWc = &pOrInfo->wc;
-  whereClauseInit(pOrWc, pWC->pParse, pMaskSet);
+  whereClauseInit(pOrWc, pWC->pParse, pMaskSet, pWC->wctrlFlags);
   whereSplit(pOrWc, pExpr, TK_OR);
   exprAnalyzeAll(pSrc, pOrWc);
   if( db->mallocFailed ) return;
@@ -80282,7 +102549,8 @@ static void exprAnalyzeOrTerm(
   /*
   ** Compute the set of tables that might satisfy cases 1 or 2.
   */
-  indexable = chngToIN = ~(Bitmask)0;
+  indexable = ~(Bitmask)0;
+  chngToIN = ~(pWC->vmask);
   for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
     if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
       WhereAndInfo *pAndInfo;
@@ -80299,9 +102567,10 @@ static void exprAnalyzeOrTerm(
         pOrTerm->wtFlags |= TERM_ANDINFO;
         pOrTerm->eOperator = WO_AND;
         pAndWC = &pAndInfo->wc;
-        whereClauseInit(pAndWC, pWC->pParse, pMaskSet);
+        whereClauseInit(pAndWC, pWC->pParse, pMaskSet, pWC->wctrlFlags);
         whereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
         exprAnalyzeAll(pSrc, pAndWC);
+        pAndWC->pOuter = pWC;
         testcase( db->mallocFailed );
         if( !db->mallocFailed ){
           for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
@@ -80343,11 +102612,27 @@ static void exprAnalyzeOrTerm(
   ** chngToIN holds a set of tables that *might* satisfy case 1.  But
   ** we have to do some additional checking to see if case 1 really
   ** is satisfied.
+  **
+  ** chngToIN will hold either 0, 1, or 2 bits.  The 0-bit case means
+  ** that there is no possibility of transforming the OR clause into an
+  ** IN operator because one or more terms in the OR clause contain
+  ** something other than == on a column in the single table.  The 1-bit
+  ** case means that every term of the OR clause is of the form
+  ** "table.column=expr" for some single table.  The one bit that is set
+  ** will correspond to the common table.  We still need to check to make
+  ** sure the same column is used on all terms.  The 2-bit case is when
+  ** the all terms are of the form "table1.column=table2.column".  It
+  ** might be possible to form an IN operator with either table1.column
+  ** or table2.column as the LHS if either is common to every term of
+  ** the OR clause.
+  **
+  ** Note that terms of the form "table.column1=table.column2" (the
+  ** same table on both sizes of the ==) cannot be optimized.
   */
   if( chngToIN ){
     int okToChngToIN = 0;     /* True if the conversion to IN is valid */
     int iColumn = -1;         /* Column index on lhs of IN operator */
-    int iCursor;              /* Table cursor common to all terms */
+    int iCursor = -1;         /* Table cursor common to all terms */
     int j = 0;                /* Loop counter */
 
     /* Search for a table and column that appears on one side or the
@@ -80361,18 +102646,38 @@ static void exprAnalyzeOrTerm(
       for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
         assert( pOrTerm->eOperator==WO_EQ );
         pOrTerm->wtFlags &= ~TERM_OR_OK;
-        if( pOrTerm->leftCursor==iColumn ) continue;
-        if( (chngToIN & getMask(pMaskSet, pOrTerm->leftCursor))==0 ) continue;
+        if( pOrTerm->leftCursor==iCursor ){
+          /* This is the 2-bit case and we are on the second iteration and
+          ** current term is from the first iteration.  So skip this term. */
+          assert( j==1 );
+          continue;
+        }
+        if( (chngToIN & getMask(pMaskSet, pOrTerm->leftCursor))==0 ){
+          /* This term must be of the form t1.a==t2.b where t2 is in the
+          ** chngToIN set but t1 is not.  This term will be either preceeded
+          ** or follwed by an inverted copy (t2.b==t1.a).  Skip this term 
+          ** and use its inversion. */
+          testcase( pOrTerm->wtFlags & TERM_COPIED );
+          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
+          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
+          continue;
+        }
         iColumn = pOrTerm->u.leftColumn;
         iCursor = pOrTerm->leftCursor;
         break;
       }
       if( i<0 ){
+        /* No candidate table+column was found.  This can only occur
+        ** on the second iteration */
         assert( j==1 );
         assert( (chngToIN&(chngToIN-1))==0 );
-        assert( chngToIN==getMask(pMaskSet, iColumn) );
+        assert( chngToIN==getMask(pMaskSet, iCursor) );
         break;
       }
+      testcase( j==1 );
+
+      /* We have found a candidate table and column.  Check to see if that
+      ** table and column is common to every term in the OR clause */
       okToChngToIN = 1;
       for(; i>=0 && okToChngToIN; i--, pOrTerm++){
         assert( pOrTerm->eOperator==WO_EQ );
@@ -80400,6 +102705,8 @@ static void exprAnalyzeOrTerm(
     /* At this point, okToChngToIN is true if original pTerm satisfies
     ** case 1.  In that case, construct a new virtual term that is 
     ** pTerm converted into an IN operator.
+    **
+    ** EV: R-00211-15100
     */
     if( okToChngToIN ){
       Expr *pDup;            /* A transient duplicate expression */
@@ -80412,17 +102719,18 @@ static void exprAnalyzeOrTerm(
         assert( pOrTerm->eOperator==WO_EQ );
         assert( pOrTerm->leftCursor==iCursor );
         assert( pOrTerm->u.leftColumn==iColumn );
-        pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight);
-        pList = sqlite3ExprListAppend(pWC->pParse, pList, pDup, 0);
+        pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight, 0);
+        pList = sqlite3ExprListAppend(pWC->pParse, pList, pDup);
         pLeft = pOrTerm->pExpr->pLeft;
       }
       assert( pLeft!=0 );
-      pDup = sqlite3ExprDup(db, pLeft);
-      pNew = sqlite3Expr(db, TK_IN, pDup, 0, 0);
+      pDup = sqlite3ExprDup(db, pLeft, 0);
+      pNew = sqlite3PExpr(pParse, TK_IN, pDup, 0, 0);
       if( pNew ){
         int idxNew;
         transferJoinMarkings(pNew, pExpr);
-        pNew->pList = pList;
+        assert( !ExprHasProperty(pNew, EP_xIsSelect) );
+        pNew->x.pList = pList;
         idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
         testcase( idxNew==0 );
         exprAnalyze(pSrc, pWC, idxNew);
@@ -80432,7 +102740,7 @@ static void exprAnalyzeOrTerm(
       }else{
         sqlite3ExprListDelete(db, pList);
       }
-      pTerm->eOperator = 0;  /* case 1 trumps case 2 */
+      pTerm->eOperator = WO_NOOP;  /* case 1 trumps case 2 */
     }
   }
 }
@@ -80467,10 +102775,10 @@ static void exprAnalyze(
   Expr *pExpr;                     /* The expression to be analyzed */
   Bitmask prereqLeft;              /* Prerequesites of the pExpr->pLeft */
   Bitmask prereqAll;               /* Prerequesites of pExpr */
-  Bitmask extraRight = 0;
-  int nPattern;
-  int isComplete;
-  int noCase;
+  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
+  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
+  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
+  int noCase = 0;                  /* LIKE/GLOB distinguishes case */
   int op;                          /* Top-level operator.  pExpr->op */
   Parse *pParse = pWC->pParse;     /* Parsing context */
   sqlite3 *db = pParse->db;        /* Database connection */
@@ -80485,8 +102793,11 @@ static void exprAnalyze(
   op = pExpr->op;
   if( op==TK_IN ){
     assert( pExpr->pRight==0 );
-    pTerm->prereqRight = exprListTableUsage(pMaskSet, pExpr->pList)
-                          | exprSelectTableUsage(pMaskSet, pExpr->pSelect);
+    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+      pTerm->prereqRight = exprSelectTableUsage(pMaskSet, pExpr->x.pSelect);
+    }else{
+      pTerm->prereqRight = exprListTableUsage(pMaskSet, pExpr->x.pList);
+    }
   }else if( op==TK_ISNULL ){
     pTerm->prereqRight = 0;
   }else{
@@ -80516,7 +102827,7 @@ static void exprAnalyze(
       Expr *pDup;
       if( pTerm->leftCursor>=0 ){
         int idxNew;
-        pDup = sqlite3ExprDup(db, pExpr);
+        pDup = sqlite3ExprDup(db, pExpr, 0);
         if( db->mallocFailed ){
           sqlite3ExprDelete(db, pDup);
           return;
@@ -80536,7 +102847,8 @@ static void exprAnalyze(
       pLeft = pDup->pLeft;
       pNew->leftCursor = pLeft->iTable;
       pNew->u.leftColumn = pLeft->iColumn;
-      pNew->prereqRight = prereqLeft;
+      testcase( (prereqLeft | extraRight) != prereqLeft );
+      pNew->prereqRight = prereqLeft | extraRight;
       pNew->prereqAll = prereqAll;
       pNew->eOperator = operatorMask(pDup->op);
     }
@@ -80559,7 +102871,7 @@ static void exprAnalyze(
   ** BETWEEN term is skipped.
   */
   else if( pExpr->op==TK_BETWEEN && pWC->op==TK_AND ){
-    ExprList *pList = pExpr->pList;
+    ExprList *pList = pExpr->x.pList;
     int i;
     static const u8 ops[] = {TK_GE, TK_LE};
     assert( pList!=0 );
@@ -80567,8 +102879,9 @@ static void exprAnalyze(
     for(i=0; i<2; i++){
       Expr *pNewExpr;
       int idxNew;
-      pNewExpr = sqlite3Expr(db, ops[i], sqlite3ExprDup(db, pExpr->pLeft),
-                             sqlite3ExprDup(db, pList->a[i].pExpr), 0);
+      pNewExpr = sqlite3PExpr(pParse, ops[i], 
+                             sqlite3ExprDup(db, pExpr->pLeft, 0),
+                             sqlite3ExprDup(db, pList->a[i].pExpr, 0), 0);
       idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
       testcase( idxNew==0 );
       exprAnalyze(pSrc, pWC, idxNew);
@@ -80586,6 +102899,7 @@ static void exprAnalyze(
   else if( pExpr->op==TK_OR ){
     assert( pWC->op==TK_AND );
     exprAnalyzeOrTerm(pSrc, pWC, idxTerm);
+    pTerm = &pWC->a[idxTerm];
   }
 #endif /* SQLITE_OMIT_OR_OPTIMIZATION */
 
@@ -80600,38 +102914,47 @@ static void exprAnalyze(
   ** The last character of the prefix "abc" is incremented to form the
   ** termination condition "abd".
   */
-  if( isLikeOrGlob(pParse, pExpr, &nPattern, &isComplete, &noCase)
-         && pWC->op==TK_AND ){
-    Expr *pLeft, *pRight;
-    Expr *pStr1, *pStr2;
-    Expr *pNewExpr1, *pNewExpr2;
-    int idxNew1, idxNew2;
+  if( pWC->op==TK_AND 
+   && isLikeOrGlob(pParse, pExpr, &pStr1, &isComplete, &noCase)
+  ){
+    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
+    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
+    Expr *pNewExpr1;
+    Expr *pNewExpr2;
+    int idxNew1;
+    int idxNew2;
+    CollSeq *pColl;    /* Collating sequence to use */
 
-    pLeft = pExpr->pList->a[1].pExpr;
-    pRight = pExpr->pList->a[0].pExpr;
-    pStr1 = sqlite3PExpr(pParse, TK_STRING, 0, 0, 0);
-    if( pStr1 ){
-      sqlite3TokenCopy(db, &pStr1->token, &pRight->token);
-      pStr1->token.n = nPattern;
-      pStr1->flags = EP_Dequoted;
-    }
-    pStr2 = sqlite3ExprDup(db, pStr1);
+    pLeft = pExpr->x.pList->a[1].pExpr;
+    pStr2 = sqlite3ExprDup(db, pStr1, 0);
     if( !db->mallocFailed ){
-      u8 c, *pC;
-      assert( pStr2->token.dyn );
-      pC = (u8*)&pStr2->token.z[nPattern-1];
+      u8 c, *pC;       /* Last character before the first wildcard */
+      pC = (u8*)&pStr2->u.zToken[sqlite3Strlen30(pStr2->u.zToken)-1];
       c = *pC;
       if( noCase ){
-        if( c=='@' ) isComplete = 0;
+        /* The point is to increment the last character before the first
+        ** wildcard.  But if we increment '@', that will push it into the
+        ** alphabetic range where case conversions will mess up the 
+        ** inequality.  To avoid this, make sure to also run the full
+        ** LIKE on all candidate expressions by clearing the isComplete flag
+        */
+        if( c=='A'-1 ) isComplete = 0;   /* EV: R-64339-08207 */
+
+
         c = sqlite3UpperToLower[c];
       }
       *pC = c + 1;
     }
-    pNewExpr1 = sqlite3PExpr(pParse, TK_GE, sqlite3ExprDup(db,pLeft), pStr1, 0);
+    pColl = sqlite3FindCollSeq(db, SQLITE_UTF8, noCase ? "NOCASE" : "BINARY",0);
+    pNewExpr1 = sqlite3PExpr(pParse, TK_GE, 
+                     sqlite3ExprSetColl(sqlite3ExprDup(db,pLeft,0), pColl),
+                     pStr1, 0);
     idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
     testcase( idxNew1==0 );
     exprAnalyze(pSrc, pWC, idxNew1);
-    pNewExpr2 = sqlite3PExpr(pParse, TK_LT, sqlite3ExprDup(db,pLeft), pStr2, 0);
+    pNewExpr2 = sqlite3PExpr(pParse, TK_LT,
+                     sqlite3ExprSetColl(sqlite3ExprDup(db,pLeft,0), pColl),
+                     pStr2, 0);
     idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
     testcase( idxNew2==0 );
     exprAnalyze(pSrc, pWC, idxNew2);
@@ -80657,13 +102980,14 @@ static void exprAnalyze(
     WhereTerm *pNewTerm;
     Bitmask prereqColumn, prereqExpr;
 
-    pRight = pExpr->pList->a[0].pExpr;
-    pLeft = pExpr->pList->a[1].pExpr;
+    pRight = pExpr->x.pList->a[0].pExpr;
+    pLeft = pExpr->x.pList->a[1].pExpr;
     prereqExpr = exprTableUsage(pMaskSet, pRight);
     prereqColumn = exprTableUsage(pMaskSet, pLeft);
     if( (prereqExpr & prereqColumn)==0 ){
       Expr *pNewExpr;
-      pNewExpr = sqlite3Expr(db, TK_MATCH, 0, sqlite3ExprDup(db, pRight), 0);
+      pNewExpr = sqlite3PExpr(pParse, TK_MATCH, 
+                              0, sqlite3ExprDup(db, pRight, 0), 0);
       idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
       testcase( idxNew==0 );
       pNewTerm = &pWC->a[idxNew];
@@ -80680,6 +103004,47 @@ static void exprAnalyze(
   }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
+#ifdef SQLITE_ENABLE_STAT3
+  /* When sqlite_stat3 histogram data is available an operator of the
+  ** form "x IS NOT NULL" can sometimes be evaluated more efficiently
+  ** as "x>NULL" if x is not an INTEGER PRIMARY KEY.  So construct a
+  ** virtual term of that form.
+  **
+  ** Note that the virtual term must be tagged with TERM_VNULL.  This
+  ** TERM_VNULL tag will suppress the not-null check at the beginning
+  ** of the loop.  Without the TERM_VNULL flag, the not-null check at
+  ** the start of the loop will prevent any results from being returned.
+  */
+  if( pExpr->op==TK_NOTNULL
+   && pExpr->pLeft->op==TK_COLUMN
+   && pExpr->pLeft->iColumn>=0
+  ){
+    Expr *pNewExpr;
+    Expr *pLeft = pExpr->pLeft;
+    int idxNew;
+    WhereTerm *pNewTerm;
+
+    pNewExpr = sqlite3PExpr(pParse, TK_GT,
+                            sqlite3ExprDup(db, pLeft, 0),
+                            sqlite3PExpr(pParse, TK_NULL, 0, 0, 0), 0);
+
+    idxNew = whereClauseInsert(pWC, pNewExpr,
+                              TERM_VIRTUAL|TERM_DYNAMIC|TERM_VNULL);
+    if( idxNew ){
+      pNewTerm = &pWC->a[idxNew];
+      pNewTerm->prereqRight = 0;
+      pNewTerm->leftCursor = pLeft->iTable;
+      pNewTerm->u.leftColumn = pLeft->iColumn;
+      pNewTerm->eOperator = WO_GT;
+      pNewTerm->iParent = idxTerm;
+      pTerm = &pWC->a[idxTerm];
+      pTerm->nChild = 1;
+      pTerm->wtFlags |= TERM_COPIED;
+      pNewTerm->prereqAll = pTerm->prereqAll;
+    }
+  }
+#endif /* SQLITE_ENABLE_STAT */
+
   /* Prevent ON clause terms of a LEFT JOIN from being used to drive
   ** an index for tables to the left of the join.
   */
@@ -80705,6 +103070,166 @@ static int referencesOtherTables(
   return 0;
 }
 
+/*
+** This function searches the expression list passed as the second argument
+** for an expression of type TK_COLUMN that refers to the same column and
+** uses the same collation sequence as the iCol'th column of index pIdx.
+** Argument iBase is the cursor number used for the table that pIdx refers
+** to.
+**
+** If such an expression is found, its index in pList->a[] is returned. If
+** no expression is found, -1 is returned.
+*/
+static int findIndexCol(
+  Parse *pParse,                  /* Parse context */
+  ExprList *pList,                /* Expression list to search */
+  int iBase,                      /* Cursor for table associated with pIdx */
+  Index *pIdx,                    /* Index to match column of */
+  int iCol                        /* Column of index to match */
+){
+  int i;
+  const char *zColl = pIdx->azColl[iCol];
+
+  for(i=0; i<pList->nExpr; i++){
+    Expr *p = pList->a[i].pExpr;
+    if( p->op==TK_COLUMN
+     && p->iColumn==pIdx->aiColumn[iCol]
+     && p->iTable==iBase
+    ){
+      CollSeq *pColl = sqlite3ExprCollSeq(pParse, p);
+      if( ALWAYS(pColl) && 0==sqlite3StrICmp(pColl->zName, zColl) ){
+        return i;
+      }
+    }
+  }
+
+  return -1;
+}
+
+/*
+** This routine determines if pIdx can be used to assist in processing a
+** DISTINCT qualifier. In other words, it tests whether or not using this
+** index for the outer loop guarantees that rows with equal values for
+** all expressions in the pDistinct list are delivered grouped together.
+**
+** For example, the query 
+**
+**   SELECT DISTINCT a, b, c FROM tbl WHERE a = ?
+**
+** can benefit from any index on columns "b" and "c".
+*/
+static int isDistinctIndex(
+  Parse *pParse,                  /* Parsing context */
+  WhereClause *pWC,               /* The WHERE clause */
+  Index *pIdx,                    /* The index being considered */
+  int base,                       /* Cursor number for the table pIdx is on */
+  ExprList *pDistinct,            /* The DISTINCT expressions */
+  int nEqCol                      /* Number of index columns with == */
+){
+  Bitmask mask = 0;               /* Mask of unaccounted for pDistinct exprs */
+  int i;                          /* Iterator variable */
+
+  if( pIdx->zName==0 || pDistinct==0 || pDistinct->nExpr>=BMS ) return 0;
+  testcase( pDistinct->nExpr==BMS-1 );
+
+  /* Loop through all the expressions in the distinct list. If any of them
+  ** are not simple column references, return early. Otherwise, test if the
+  ** WHERE clause contains a "col=X" clause. If it does, the expression
+  ** can be ignored. If it does not, and the column does not belong to the
+  ** same table as index pIdx, return early. Finally, if there is no
+  ** matching "col=X" expression and the column is on the same table as pIdx,
+  ** set the corresponding bit in variable mask.
+  */
+  for(i=0; i<pDistinct->nExpr; i++){
+    WhereTerm *pTerm;
+    Expr *p = pDistinct->a[i].pExpr;
+    if( p->op!=TK_COLUMN ) return 0;
+    pTerm = findTerm(pWC, p->iTable, p->iColumn, ~(Bitmask)0, WO_EQ, 0);
+    if( pTerm ){
+      Expr *pX = pTerm->pExpr;
+      CollSeq *p1 = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
+      CollSeq *p2 = sqlite3ExprCollSeq(pParse, p);
+      if( p1==p2 ) continue;
+    }
+    if( p->iTable!=base ) return 0;
+    mask |= (((Bitmask)1) << i);
+  }
+
+  for(i=nEqCol; mask && i<pIdx->nColumn; i++){
+    int iExpr = findIndexCol(pParse, pDistinct, base, pIdx, i);
+    if( iExpr<0 ) break;
+    mask &= ~(((Bitmask)1) << iExpr);
+  }
+
+  return (mask==0);
+}
+
+
+/*
+** Return true if the DISTINCT expression-list passed as the third argument
+** is redundant. A DISTINCT list is redundant if the database contains a
+** UNIQUE index that guarantees that the result of the query will be distinct
+** anyway.
+*/
+static int isDistinctRedundant(
+  Parse *pParse,
+  SrcList *pTabList,
+  WhereClause *pWC,
+  ExprList *pDistinct
+){
+  Table *pTab;
+  Index *pIdx;
+  int i;                          
+  int iBase;
+
+  /* If there is more than one table or sub-select in the FROM clause of
+  ** this query, then it will not be possible to show that the DISTINCT 
+  ** clause is redundant. */
+  if( pTabList->nSrc!=1 ) return 0;
+  iBase = pTabList->a[0].iCursor;
+  pTab = pTabList->a[0].pTab;
+
+  /* If any of the expressions is an IPK column on table iBase, then return 
+  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
+  ** current SELECT is a correlated sub-query.
+  */
+  for(i=0; i<pDistinct->nExpr; i++){
+    Expr *p = pDistinct->a[i].pExpr;
+    if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1;
+  }
+
+  /* Loop through all indices on the table, checking each to see if it makes
+  ** the DISTINCT qualifier redundant. It does so if:
+  **
+  **   1. The index is itself UNIQUE, and
+  **
+  **   2. All of the columns in the index are either part of the pDistinct
+  **      list, or else the WHERE clause contains a term of the form "col=X",
+  **      where X is a constant value. The collation sequences of the
+  **      comparison and select-list expressions must match those of the index.
+  **
+  **   3. All of those index columns for which the WHERE clause does not
+  **      contain a "col=X" term are subject to a NOT NULL constraint.
+  */
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    if( pIdx->onError==OE_None ) continue;
+    for(i=0; i<pIdx->nColumn; i++){
+      int iCol = pIdx->aiColumn[i];
+      if( 0==findTerm(pWC, iBase, iCol, ~(Bitmask)0, WO_EQ, pIdx) ){
+        int iIdxCol = findIndexCol(pParse, pDistinct, iBase, pIdx, i);
+        if( iIdxCol<0 || pTab->aCol[pIdx->aiColumn[i]].notNull==0 ){
+          break;
+        }
+      }
+    }
+    if( i==pIdx->nColumn ){
+      /* This index implies that the DISTINCT qualifier is redundant. */
+      return 1;
+    }
+  }
+
+  return 0;
+}
 
 /*
 ** This routine decides if pIdx can be used to satisfy the ORDER BY
@@ -80732,6 +103257,7 @@ static int isSortingIndex(
   int base,               /* Cursor number for the table to be sorted */
   ExprList *pOrderBy,     /* The ORDER BY clause */
   int nEqCol,             /* Number of index columns with == constraints */
+  int wsFlags,            /* Index usages flags */
   int *pbRev              /* Set to 1 if ORDER BY is DESC */
 ){
   int i, j;                       /* Loop counters */
@@ -80740,10 +103266,18 @@ static int isSortingIndex(
   struct ExprList_item *pTerm;    /* A term of the ORDER BY clause */
   sqlite3 *db = pParse->db;
 
-  assert( pOrderBy!=0 );
+  if( !pOrderBy ) return 0;
+  if( wsFlags & WHERE_COLUMN_IN ) return 0;
+  if( pIdx->bUnordered ) return 0;
+
   nTerm = pOrderBy->nExpr;
   assert( nTerm>0 );
 
+  /* Argument pIdx must either point to a 'real' named index structure, 
+  ** or an index structure allocated on the stack by bestBtreeIndex() to
+  ** represent the rowid index that is part of every table.  */
+  assert( pIdx->zName || (pIdx->nColumn==1 && pIdx->aiColumn[0]==-1) );
+
   /* Match terms of the ORDER BY clause against columns of
   ** the index.
   **
@@ -80770,7 +103304,7 @@ static int isSortingIndex(
     if( !pColl ){
       pColl = db->pDfltColl;
     }
-    if( i<pIdx->nColumn ){
+    if( pIdx->zName && i<pIdx->nColumn ){
       iColumn = pIdx->aiColumn[i];
       if( iColumn==pIdx->pTable->iPKey ){
         iColumn = -1;
@@ -80799,7 +103333,7 @@ static int isSortingIndex(
         return 0;
       }
     }
-    assert( pIdx->aSortOrder!=0 );
+    assert( pIdx->aSortOrder!=0 || iColumn==-1 );
     assert( pTerm->sortOrder==0 || pTerm->sortOrder==1 );
     assert( iSortOrder==0 || iSortOrder==1 );
     termSortOrder = iSortOrder ^ pTerm->sortOrder;
@@ -80832,36 +103366,26 @@ static int isSortingIndex(
     return 1;
   }
   if( pIdx->onError!=OE_None && i==pIdx->nColumn
-      && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
-    /* All terms of this index match some prefix of the ORDER BY clause
-    ** and the index is UNIQUE and no terms on the tail of the ORDER BY
-    ** clause reference other tables in a join.  If this is all true then
-    ** the order by clause is superfluous. */
-    return 1;
-  }
-  return 0;
-}
+      && (wsFlags & WHERE_COLUMN_NULL)==0
+      && !referencesOtherTables(pOrderBy, pMaskSet, j, base) 
+  ){
+    Column *aCol = pIdx->pTable->aCol;
 
-/*
-** Check table to see if the ORDER BY clause in pOrderBy can be satisfied
-** by sorting in order of ROWID.  Return true if so and set *pbRev to be
-** true for reverse ROWID and false for forward ROWID order.
-*/
-static int sortableByRowid(
-  int base,               /* Cursor number for table to be sorted */
-  ExprList *pOrderBy,     /* The ORDER BY clause */
-  WhereMaskSet *pMaskSet, /* Mapping from table cursors to bitmaps */
-  int *pbRev              /* Set to 1 if ORDER BY is DESC */
-){
-  Expr *p;
-
-  assert( pOrderBy!=0 );
-  assert( pOrderBy->nExpr>0 );
-  p = pOrderBy->a[0].pExpr;
-  if( p->op==TK_COLUMN && p->iTable==base && p->iColumn==-1
-    && !referencesOtherTables(pOrderBy, pMaskSet, 1, base) ){
-    *pbRev = pOrderBy->a[0].sortOrder;
-    return 1;
+    /* All terms of this index match some prefix of the ORDER BY clause,
+    ** the index is UNIQUE, and no terms on the tail of the ORDER BY
+    ** refer to other tables in a join. So, assuming that the index entries
+    ** visited contain no NULL values, then this index delivers rows in
+    ** the required order.
+    **
+    ** It is not possible for any of the first nEqCol index fields to be
+    ** NULL (since the corresponding "=" operator in the WHERE clause would 
+    ** not be true). So if all remaining index columns have NOT NULL 
+    ** constaints attached to them, we can be confident that the visited
+    ** index entries are free of NULLs.  */
+    for(i=nEqCol; i<pIdx->nColumn; i++){
+      if( aCol[pIdx->aiColumn[i]].notNull==0 ) break;
+    }
+    return (i==pIdx->nColumn);
   }
   return 0;
 }
@@ -80927,7 +103451,509 @@ static void TRACE_IDX_OUTPUTS(sqlite3_index_info *p){
 #define TRACE_IDX_OUTPUTS(A)
 #endif
 
+/* 
+** Required because bestIndex() is called by bestOrClauseIndex() 
+*/
+static void bestIndex(
+    Parse*, WhereClause*, struct SrcList_item*,
+    Bitmask, Bitmask, ExprList*, WhereCost*);
+
+/*
+** This routine attempts to find an scanning strategy that can be used 
+** to optimize an 'OR' expression that is part of a WHERE clause. 
+**
+** The table associated with FROM clause term pSrc may be either a
+** regular B-Tree table or a virtual table.
+*/
+static void bestOrClauseIndex(
+  Parse *pParse,              /* The parsing context */
+  WhereClause *pWC,           /* The WHERE clause */
+  struct SrcList_item *pSrc,  /* The FROM clause term to search */
+  Bitmask notReady,           /* Mask of cursors not available for indexing */
+  Bitmask notValid,           /* Cursors not available for any purpose */
+  ExprList *pOrderBy,         /* The ORDER BY clause */
+  WhereCost *pCost            /* Lowest cost query plan */
+){
+#ifndef SQLITE_OMIT_OR_OPTIMIZATION
+  const int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
+  const Bitmask maskSrc = getMask(pWC->pMaskSet, iCur);  /* Bitmask for pSrc */
+  WhereTerm * const pWCEnd = &pWC->a[pWC->nTerm];        /* End of pWC->a[] */
+  WhereTerm *pTerm;                 /* A single term of the WHERE clause */
+
+  /* The OR-clause optimization is disallowed if the INDEXED BY or
+  ** NOT INDEXED clauses are used or if the WHERE_AND_ONLY bit is set. */
+  if( pSrc->notIndexed || pSrc->pIndex!=0 ){
+    return;
+  }
+  if( pWC->wctrlFlags & WHERE_AND_ONLY ){
+    return;
+  }
+
+  /* Search the WHERE clause terms for a usable WO_OR term. */
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    if( pTerm->eOperator==WO_OR 
+     && ((pTerm->prereqAll & ~maskSrc) & notReady)==0
+     && (pTerm->u.pOrInfo->indexable & maskSrc)!=0 
+    ){
+      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
+      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
+      WhereTerm *pOrTerm;
+      int flags = WHERE_MULTI_OR;
+      double rTotal = 0;
+      double nRow = 0;
+      Bitmask used = 0;
+
+      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
+        WhereCost sTermCost;
+        WHERETRACE(("... Multi-index OR testing for term %d of %d....\n", 
+          (pOrTerm - pOrWC->a), (pTerm - pWC->a)
+        ));
+        if( pOrTerm->eOperator==WO_AND ){
+          WhereClause *pAndWC = &pOrTerm->u.pAndInfo->wc;
+          bestIndex(pParse, pAndWC, pSrc, notReady, notValid, 0, &sTermCost);
+        }else if( pOrTerm->leftCursor==iCur ){
+          WhereClause tempWC;
+          tempWC.pParse = pWC->pParse;
+          tempWC.pMaskSet = pWC->pMaskSet;
+          tempWC.pOuter = pWC;
+          tempWC.op = TK_AND;
+          tempWC.a = pOrTerm;
+          tempWC.wctrlFlags = 0;
+          tempWC.nTerm = 1;
+          bestIndex(pParse, &tempWC, pSrc, notReady, notValid, 0, &sTermCost);
+        }else{
+          continue;
+        }
+        rTotal += sTermCost.rCost;
+        nRow += sTermCost.plan.nRow;
+        used |= sTermCost.used;
+        if( rTotal>=pCost->rCost ) break;
+      }
+
+      /* If there is an ORDER BY clause, increase the scan cost to account 
+      ** for the cost of the sort. */
+      if( pOrderBy!=0 ){
+        WHERETRACE(("... sorting increases OR cost %.9g to %.9g\n",
+                    rTotal, rTotal+nRow*estLog(nRow)));
+        rTotal += nRow*estLog(nRow);
+      }
+
+      /* If the cost of scanning using this OR term for optimization is
+      ** less than the current cost stored in pCost, replace the contents
+      ** of pCost. */
+      WHERETRACE(("... multi-index OR cost=%.9g nrow=%.9g\n", rTotal, nRow));
+      if( rTotal<pCost->rCost ){
+        pCost->rCost = rTotal;
+        pCost->used = used;
+        pCost->plan.nRow = nRow;
+        pCost->plan.wsFlags = flags;
+        pCost->plan.u.pTerm = pTerm;
+      }
+    }
+  }
+#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
+}
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+/*
+** Return TRUE if the WHERE clause term pTerm is of a form where it
+** could be used with an index to access pSrc, assuming an appropriate
+** index existed.
+*/
+static int termCanDriveIndex(
+  WhereTerm *pTerm,              /* WHERE clause term to check */
+  struct SrcList_item *pSrc,     /* Table we are trying to access */
+  Bitmask notReady               /* Tables in outer loops of the join */
+){
+  char aff;
+  if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
+  if( pTerm->eOperator!=WO_EQ ) return 0;
+  if( (pTerm->prereqRight & notReady)!=0 ) return 0;
+  aff = pSrc->pTab->aCol[pTerm->u.leftColumn].affinity;
+  if( !sqlite3IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
+  return 1;
+}
+#endif
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+/*
+** If the query plan for pSrc specified in pCost is a full table scan
+** and indexing is allows (if there is no NOT INDEXED clause) and it
+** possible to construct a transient index that would perform better
+** than a full table scan even when the cost of constructing the index
+** is taken into account, then alter the query plan to use the
+** transient index.
+*/
+static void bestAutomaticIndex(
+  Parse *pParse,              /* The parsing context */
+  WhereClause *pWC,           /* The WHERE clause */
+  struct SrcList_item *pSrc,  /* The FROM clause term to search */
+  Bitmask notReady,           /* Mask of cursors that are not available */
+  WhereCost *pCost            /* Lowest cost query plan */
+){
+  double nTableRow;           /* Rows in the input table */
+  double logN;                /* log(nTableRow) */
+  double costTempIdx;         /* per-query cost of the transient index */
+  WhereTerm *pTerm;           /* A single term of the WHERE clause */
+  WhereTerm *pWCEnd;          /* End of pWC->a[] */
+  Table *pTable;              /* Table tht might be indexed */
+
+  if( pParse->nQueryLoop<=(double)1 ){
+    /* There is no point in building an automatic index for a single scan */
+    return;
+  }
+  if( (pParse->db->flags & SQLITE_AutoIndex)==0 ){
+    /* Automatic indices are disabled at run-time */
+    return;
+  }
+  if( (pCost->plan.wsFlags & WHERE_NOT_FULLSCAN)!=0 ){
+    /* We already have some kind of index in use for this query. */
+    return;
+  }
+  if( pSrc->notIndexed ){
+    /* The NOT INDEXED clause appears in the SQL. */
+    return;
+  }
+  if( pSrc->isCorrelated ){
+    /* The source is a correlated sub-query. No point in indexing it. */
+    return;
+  }
+
+  assert( pParse->nQueryLoop >= (double)1 );
+  pTable = pSrc->pTab;
+  nTableRow = pTable->nRowEst;
+  logN = estLog(nTableRow);
+  costTempIdx = 2*logN*(nTableRow/pParse->nQueryLoop + 1);
+  if( costTempIdx>=pCost->rCost ){
+    /* The cost of creating the transient table would be greater than
+    ** doing the full table scan */
+    return;
+  }
+
+  /* Search for any equality comparison term */
+  pWCEnd = &pWC->a[pWC->nTerm];
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
+      WHERETRACE(("auto-index reduces cost from %.1f to %.1f\n",
+                    pCost->rCost, costTempIdx));
+      pCost->rCost = costTempIdx;
+      pCost->plan.nRow = logN + 1;
+      pCost->plan.wsFlags = WHERE_TEMP_INDEX;
+      pCost->used = pTerm->prereqRight;
+      break;
+    }
+  }
+}
+#else
+# define bestAutomaticIndex(A,B,C,D,E)  /* no-op */
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+/*
+** Generate code to construct the Index object for an automatic index
+** and to set up the WhereLevel object pLevel so that the code generator
+** makes use of the automatic index.
+*/
+static void constructAutomaticIndex(
+  Parse *pParse,              /* The parsing context */
+  WhereClause *pWC,           /* The WHERE clause */
+  struct SrcList_item *pSrc,  /* The FROM clause term to get the next index */
+  Bitmask notReady,           /* Mask of cursors that are not available */
+  WhereLevel *pLevel          /* Write new index here */
+){
+  int nColumn;                /* Number of columns in the constructed index */
+  WhereTerm *pTerm;           /* A single term of the WHERE clause */
+  WhereTerm *pWCEnd;          /* End of pWC->a[] */
+  int nByte;                  /* Byte of memory needed for pIdx */
+  Index *pIdx;                /* Object describing the transient index */
+  Vdbe *v;                    /* Prepared statement under construction */
+  int addrInit;               /* Address of the initialization bypass jump */
+  Table *pTable;              /* The table being indexed */
+  KeyInfo *pKeyinfo;          /* Key information for the index */   
+  int addrTop;                /* Top of the index fill loop */
+  int regRecord;              /* Register holding an index record */
+  int n;                      /* Column counter */
+  int i;                      /* Loop counter */
+  int mxBitCol;               /* Maximum column in pSrc->colUsed */
+  CollSeq *pColl;             /* Collating sequence to on a column */
+  Bitmask idxCols;            /* Bitmap of columns used for indexing */
+  Bitmask extraCols;          /* Bitmap of additional columns */
+
+  /* Generate code to skip over the creation and initialization of the
+  ** transient index on 2nd and subsequent iterations of the loop. */
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  addrInit = sqlite3CodeOnce(pParse);
+
+  /* Count the number of columns that will be added to the index
+  ** and used to match WHERE clause constraints */
+  nColumn = 0;
+  pTable = pSrc->pTab;
+  pWCEnd = &pWC->a[pWC->nTerm];
+  idxCols = 0;
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
+      int iCol = pTerm->u.leftColumn;
+      Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;
+      testcase( iCol==BMS );
+      testcase( iCol==BMS-1 );
+      if( (idxCols & cMask)==0 ){
+        nColumn++;
+        idxCols |= cMask;
+      }
+    }
+  }
+  assert( nColumn>0 );
+  pLevel->plan.nEq = nColumn;
+
+  /* Count the number of additional columns needed to create a
+  ** covering index.  A "covering index" is an index that contains all
+  ** columns that are needed by the query.  With a covering index, the
+  ** original table never needs to be accessed.  Automatic indices must
+  ** be a covering index because the index will not be updated if the
+  ** original table changes and the index and table cannot both be used
+  ** if they go out of sync.
+  */
+  extraCols = pSrc->colUsed & (~idxCols | (((Bitmask)1)<<(BMS-1)));
+  mxBitCol = (pTable->nCol >= BMS-1) ? BMS-1 : pTable->nCol;
+  testcase( pTable->nCol==BMS-1 );
+  testcase( pTable->nCol==BMS-2 );
+  for(i=0; i<mxBitCol; i++){
+    if( extraCols & (((Bitmask)1)<<i) ) nColumn++;
+  }
+  if( pSrc->colUsed & (((Bitmask)1)<<(BMS-1)) ){
+    nColumn += pTable->nCol - BMS + 1;
+  }
+  pLevel->plan.wsFlags |= WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WO_EQ;
+
+  /* Construct the Index object to describe this index */
+  nByte = sizeof(Index);
+  nByte += nColumn*sizeof(int);     /* Index.aiColumn */
+  nByte += nColumn*sizeof(char*);   /* Index.azColl */
+  nByte += nColumn;                 /* Index.aSortOrder */
+  pIdx = sqlite3DbMallocZero(pParse->db, nByte);
+  if( pIdx==0 ) return;
+  pLevel->plan.u.pIdx = pIdx;
+  pIdx->azColl = (char**)&pIdx[1];
+  pIdx->aiColumn = (int*)&pIdx->azColl[nColumn];
+  pIdx->aSortOrder = (u8*)&pIdx->aiColumn[nColumn];
+  pIdx->zName = "auto-index";
+  pIdx->nColumn = nColumn;
+  pIdx->pTable = pTable;
+  n = 0;
+  idxCols = 0;
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
+      int iCol = pTerm->u.leftColumn;
+      Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;
+      if( (idxCols & cMask)==0 ){
+        Expr *pX = pTerm->pExpr;
+        idxCols |= cMask;
+        pIdx->aiColumn[n] = pTerm->u.leftColumn;
+        pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
+        pIdx->azColl[n] = ALWAYS(pColl) ? pColl->zName : "BINARY";
+        n++;
+      }
+    }
+  }
+  assert( (u32)n==pLevel->plan.nEq );
+
+  /* Add additional columns needed to make the automatic index into
+  ** a covering index */
+  for(i=0; i<mxBitCol; i++){
+    if( extraCols & (((Bitmask)1)<<i) ){
+      pIdx->aiColumn[n] = i;
+      pIdx->azColl[n] = "BINARY";
+      n++;
+    }
+  }
+  if( pSrc->colUsed & (((Bitmask)1)<<(BMS-1)) ){
+    for(i=BMS-1; i<pTable->nCol; i++){
+      pIdx->aiColumn[n] = i;
+      pIdx->azColl[n] = "BINARY";
+      n++;
+    }
+  }
+  assert( n==nColumn );
+
+  /* Create the automatic index */
+  pKeyinfo = sqlite3IndexKeyinfo(pParse, pIdx);
+  assert( pLevel->iIdxCur>=0 );
+  sqlite3VdbeAddOp4(v, OP_OpenAutoindex, pLevel->iIdxCur, nColumn+1, 0,
+                    (char*)pKeyinfo, P4_KEYINFO_HANDOFF);
+  VdbeComment((v, "for %s", pTable->zName));
+
+  /* Fill the automatic index with content */
+  addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur);
+  regRecord = sqlite3GetTempReg(pParse);
+  sqlite3GenerateIndexKey(pParse, pIdx, pLevel->iTabCur, regRecord, 1);
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
+  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+  sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
+  sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX);
+  sqlite3VdbeJumpHere(v, addrTop);
+  sqlite3ReleaseTempReg(pParse, regRecord);
+  
+  /* Jump here when skipping the initialization */
+  sqlite3VdbeJumpHere(v, addrInit);
+}
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
 #ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Allocate and populate an sqlite3_index_info structure. It is the 
+** responsibility of the caller to eventually release the structure
+** by passing the pointer returned by this function to sqlite3_free().
+*/
+static sqlite3_index_info *allocateIndexInfo(
+  Parse *pParse, 
+  WhereClause *pWC,
+  struct SrcList_item *pSrc,
+  ExprList *pOrderBy
+){
+  int i, j;
+  int nTerm;
+  struct sqlite3_index_constraint *pIdxCons;
+  struct sqlite3_index_orderby *pIdxOrderBy;
+  struct sqlite3_index_constraint_usage *pUsage;
+  WhereTerm *pTerm;
+  int nOrderBy;
+  sqlite3_index_info *pIdxInfo;
+
+  WHERETRACE(("Recomputing index info for %s...\n", pSrc->pTab->zName));
+
+  /* Count the number of possible WHERE clause constraints referring
+  ** to this virtual table */
+  for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+    if( pTerm->leftCursor != pSrc->iCursor ) continue;
+    assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
+    testcase( pTerm->eOperator==WO_IN );
+    testcase( pTerm->eOperator==WO_ISNULL );
+    if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
+    if( pTerm->wtFlags & TERM_VNULL ) continue;
+    nTerm++;
+  }
+
+  /* If the ORDER BY clause contains only columns in the current 
+  ** virtual table then allocate space for the aOrderBy part of
+  ** the sqlite3_index_info structure.
+  */
+  nOrderBy = 0;
+  if( pOrderBy ){
+    for(i=0; i<pOrderBy->nExpr; i++){
+      Expr *pExpr = pOrderBy->a[i].pExpr;
+      if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
+    }
+    if( i==pOrderBy->nExpr ){
+      nOrderBy = pOrderBy->nExpr;
+    }
+  }
+
+  /* Allocate the sqlite3_index_info structure
+  */
+  pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
+                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
+                           + sizeof(*pIdxOrderBy)*nOrderBy );
+  if( pIdxInfo==0 ){
+    sqlite3ErrorMsg(pParse, "out of memory");
+    /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+    return 0;
+  }
+
+  /* Initialize the structure.  The sqlite3_index_info structure contains
+  ** many fields that are declared "const" to prevent xBestIndex from
+  ** changing them.  We have to do some funky casting in order to
+  ** initialize those fields.
+  */
+  pIdxCons = (struct sqlite3_index_constraint*)&pIdxInfo[1];
+  pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
+  pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
+  *(int*)&pIdxInfo->nConstraint = nTerm;
+  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
+  *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
+  *(struct sqlite3_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
+  *(struct sqlite3_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
+                                                                   pUsage;
+
+  for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+    if( pTerm->leftCursor != pSrc->iCursor ) continue;
+    assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
+    testcase( pTerm->eOperator==WO_IN );
+    testcase( pTerm->eOperator==WO_ISNULL );
+    if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
+    if( pTerm->wtFlags & TERM_VNULL ) continue;
+    pIdxCons[j].iColumn = pTerm->u.leftColumn;
+    pIdxCons[j].iTermOffset = i;
+    pIdxCons[j].op = (u8)pTerm->eOperator;
+    /* The direct assignment in the previous line is possible only because
+    ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical.  The
+    ** following asserts verify this fact. */
+    assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
+    assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
+    assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
+    assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
+    assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
+    assert( WO_MATCH==SQLITE_INDEX_CONSTRAINT_MATCH );
+    assert( pTerm->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
+    j++;
+  }
+  for(i=0; i<nOrderBy; i++){
+    Expr *pExpr = pOrderBy->a[i].pExpr;
+    pIdxOrderBy[i].iColumn = pExpr->iColumn;
+    pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
+  }
+
+  return pIdxInfo;
+}
+
+/*
+** The table object reference passed as the second argument to this function
+** must represent a virtual table. This function invokes the xBestIndex()
+** method of the virtual table with the sqlite3_index_info pointer passed
+** as the argument.
+**
+** If an error occurs, pParse is populated with an error message and a
+** non-zero value is returned. Otherwise, 0 is returned and the output
+** part of the sqlite3_index_info structure is left populated.
+**
+** Whether or not an error is returned, it is the responsibility of the
+** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
+** that this is required.
+*/
+static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){
+  sqlite3_vtab *pVtab = sqlite3GetVTable(pParse->db, pTab)->pVtab;
+  int i;
+  int rc;
+
+  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
+  TRACE_IDX_INPUTS(p);
+  rc = pVtab->pModule->xBestIndex(pVtab, p);
+  TRACE_IDX_OUTPUTS(p);
+
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ){
+      pParse->db->mallocFailed = 1;
+    }else if( !pVtab->zErrMsg ){
+      sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
+    }else{
+      sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg);
+    }
+  }
+  sqlite3_free(pVtab->zErrMsg);
+  pVtab->zErrMsg = 0;
+
+  for(i=0; i<p->nConstraint; i++){
+    if( !p->aConstraint[i].usable && p->aConstraintUsage[i].argvIndex>0 ){
+      sqlite3ErrorMsg(pParse, 
+          "table %s: xBestIndex returned an invalid plan", pTab->zName);
+    }
+  }
+
+  return pParse->nErr;
+}
+
+
 /*
 ** Compute the best index for a virtual table.
 **
@@ -80944,113 +103970,41 @@ static void TRACE_IDX_OUTPUTS(sqlite3_index_info *p){
 ** routine takes care of freeing the sqlite3_index_info structure after
 ** everybody has finished with it.
 */
-static double bestVirtualIndex(
-  Parse *pParse,                 /* The parsing context */
-  WhereClause *pWC,              /* The WHERE clause */
-  struct SrcList_item *pSrc,     /* The FROM clause term to search */
-  Bitmask notReady,              /* Mask of cursors that are not available */
-  ExprList *pOrderBy,            /* The order by clause */
-  int orderByUsable,             /* True if we can potential sort */
-  sqlite3_index_info **ppIdxInfo /* Index information passed to xBestIndex */
+static void bestVirtualIndex(
+  Parse *pParse,                  /* The parsing context */
+  WhereClause *pWC,               /* The WHERE clause */
+  struct SrcList_item *pSrc,      /* The FROM clause term to search */
+  Bitmask notReady,               /* Mask of cursors not available for index */
+  Bitmask notValid,               /* Cursors not valid for any purpose */
+  ExprList *pOrderBy,             /* The order by clause */
+  WhereCost *pCost,               /* Lowest cost query plan */
+  sqlite3_index_info **ppIdxInfo  /* Index information passed to xBestIndex */
 ){
   Table *pTab = pSrc->pTab;
-  sqlite3_vtab *pVtab = pTab->pVtab;
   sqlite3_index_info *pIdxInfo;
   struct sqlite3_index_constraint *pIdxCons;
-  struct sqlite3_index_orderby *pIdxOrderBy;
   struct sqlite3_index_constraint_usage *pUsage;
   WhereTerm *pTerm;
   int i, j;
   int nOrderBy;
-  int rc;
+  double rCost;
+
+  /* Make sure wsFlags is initialized to some sane value. Otherwise, if the 
+  ** malloc in allocateIndexInfo() fails and this function returns leaving
+  ** wsFlags in an uninitialized state, the caller may behave unpredictably.
+  */
+  memset(pCost, 0, sizeof(*pCost));
+  pCost->plan.wsFlags = WHERE_VIRTUALTABLE;
 
   /* If the sqlite3_index_info structure has not been previously
-  ** allocated and initialized for this virtual table, then allocate
-  ** and initialize it now
+  ** allocated and initialized, then allocate and initialize it now.
   */
   pIdxInfo = *ppIdxInfo;
   if( pIdxInfo==0 ){
-    int nTerm;
-    WHERETRACE(("Recomputing index info for %s...\n", pTab->zName));
-
-    /* Count the number of possible WHERE clause constraints referring
-    ** to this virtual table */
-    for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
-      if( pTerm->leftCursor != pSrc->iCursor ) continue;
-      assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
-      testcase( pTerm->eOperator==WO_IN );
-      testcase( pTerm->eOperator==WO_ISNULL );
-      if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
-      nTerm++;
-    }
-
-    /* If the ORDER BY clause contains only columns in the current 
-    ** virtual table then allocate space for the aOrderBy part of
-    ** the sqlite3_index_info structure.
-    */
-    nOrderBy = 0;
-    if( pOrderBy ){
-      for(i=0; i<pOrderBy->nExpr; i++){
-        Expr *pExpr = pOrderBy->a[i].pExpr;
-        if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
-      }
-      if( i==pOrderBy->nExpr ){
-        nOrderBy = pOrderBy->nExpr;
-      }
-    }
-
-    /* Allocate the sqlite3_index_info structure
-    */
-    pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
-                             + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
-                             + sizeof(*pIdxOrderBy)*nOrderBy );
-    if( pIdxInfo==0 ){
-      sqlite3ErrorMsg(pParse, "out of memory");
-      return 0.0;
-    }
-    *ppIdxInfo = pIdxInfo;
-
-    /* Initialize the structure.  The sqlite3_index_info structure contains
-    ** many fields that are declared "const" to prevent xBestIndex from
-    ** changing them.  We have to do some funky casting in order to
-    ** initialize those fields.
-    */
-    pIdxCons = (struct sqlite3_index_constraint*)&pIdxInfo[1];
-    pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
-    pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
-    *(int*)&pIdxInfo->nConstraint = nTerm;
-    *(int*)&pIdxInfo->nOrderBy = nOrderBy;
-    *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
-    *(struct sqlite3_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
-    *(struct sqlite3_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
-                                                                     pUsage;
-
-    for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
-      if( pTerm->leftCursor != pSrc->iCursor ) continue;
-      assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
-      testcase( pTerm->eOperator==WO_IN );
-      testcase( pTerm->eOperator==WO_ISNULL );
-      if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
-      pIdxCons[j].iColumn = pTerm->u.leftColumn;
-      pIdxCons[j].iTermOffset = i;
-      pIdxCons[j].op = (u8)pTerm->eOperator;
-      /* The direct assignment in the previous line is possible only because
-      ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical.  The
-      ** following asserts verify this fact. */
-      assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
-      assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
-      assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
-      assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
-      assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
-      assert( WO_MATCH==SQLITE_INDEX_CONSTRAINT_MATCH );
-      assert( pTerm->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
-      j++;
-    }
-    for(i=0; i<nOrderBy; i++){
-      Expr *pExpr = pOrderBy->a[i].pExpr;
-      pIdxOrderBy[i].iColumn = pExpr->iColumn;
-      pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
-    }
+    *ppIdxInfo = pIdxInfo = allocateIndexInfo(pParse, pWC, pSrc, pOrderBy);
+  }
+  if( pIdxInfo==0 ){
+    return;
   }
 
   /* At this point, the sqlite3_index_info structure that pIdxInfo points
@@ -81065,14 +104019,7 @@ static double bestVirtualIndex(
   ** sqlite3ViewGetColumnNames() would have picked up the error. 
   */
   assert( pTab->azModuleArg && pTab->azModuleArg[0] );
-  assert( pVtab );
-#if 0
-  if( pTab->pVtab==0 ){
-    sqlite3ErrorMsg(pParse, "undefined module %s for table %s",
-        pTab->azModuleArg[0], pTab->zName);
-    return 0.0;
-  }
-#endif
+  assert( sqlite3GetVTable(pParse->db, pTab) );
 
   /* Set the aConstraint[].usable fields and initialize all 
   ** output variables to zero.
@@ -81099,7 +104046,7 @@ static double bestVirtualIndex(
   for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
     j = pIdxCons->iTermOffset;
     pTerm = &pWC->a[j];
-    pIdxCons->usable =  (pTerm->prereqRight & notReady)==0 ?1:0;
+    pIdxCons->usable = (pTerm->prereqRight&notReady) ? 0 : 1;
   }
   memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
   if( pIdxInfo->needToFreeIdxStr ){
@@ -81109,51 +104056,462 @@ static double bestVirtualIndex(
   pIdxInfo->idxNum = 0;
   pIdxInfo->needToFreeIdxStr = 0;
   pIdxInfo->orderByConsumed = 0;
-  pIdxInfo->estimatedCost = SQLITE_BIG_DBL / 2.0;
+  /* ((double)2) In case of SQLITE_OMIT_FLOATING_POINT... */
+  pIdxInfo->estimatedCost = SQLITE_BIG_DBL / ((double)2);
   nOrderBy = pIdxInfo->nOrderBy;
-  if( pIdxInfo->nOrderBy && !orderByUsable ){
-    *(int*)&pIdxInfo->nOrderBy = 0;
+  if( !pOrderBy ){
+    pIdxInfo->nOrderBy = 0;
   }
 
-  (void)sqlite3SafetyOff(pParse->db);
-  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
-  TRACE_IDX_INPUTS(pIdxInfo);
-  rc = pVtab->pModule->xBestIndex(pVtab, pIdxInfo);
-  TRACE_IDX_OUTPUTS(pIdxInfo);
-  (void)sqlite3SafetyOn(pParse->db);
-
-  if( rc!=SQLITE_OK ){
-    if( rc==SQLITE_NOMEM ){
-      pParse->db->mallocFailed = 1;
-    }else if( !pVtab->zErrMsg ){
-      sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
-    }else{
-      sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg);
-    }
+  if( vtabBestIndex(pParse, pTab, pIdxInfo) ){
+    return;
   }
-  sqlite3DbFree(pParse->db, pVtab->zErrMsg);
-  pVtab->zErrMsg = 0;
 
+  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
   for(i=0; i<pIdxInfo->nConstraint; i++){
-    if( !pIdxInfo->aConstraint[i].usable && pUsage[i].argvIndex>0 ){
-      sqlite3ErrorMsg(pParse, 
-          "table %s: xBestIndex returned an invalid plan", pTab->zName);
-      return 0.0;
+    if( pUsage[i].argvIndex>0 ){
+      pCost->used |= pWC->a[pIdxCons[i].iTermOffset].prereqRight;
     }
   }
 
-  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
-  return pIdxInfo->estimatedCost;
+  /* If there is an ORDER BY clause, and the selected virtual table index
+  ** does not satisfy it, increase the cost of the scan accordingly. This
+  ** matches the processing for non-virtual tables in bestBtreeIndex().
+  */
+  rCost = pIdxInfo->estimatedCost;
+  if( pOrderBy && pIdxInfo->orderByConsumed==0 ){
+    rCost += estLog(rCost)*rCost;
+  }
+
+  /* The cost is not allowed to be larger than SQLITE_BIG_DBL (the
+  ** inital value of lowestCost in this loop. If it is, then the
+  ** (cost<lowestCost) test below will never be true.
+  ** 
+  ** Use "(double)2" instead of "2.0" in case OMIT_FLOATING_POINT 
+  ** is defined.
+  */
+  if( (SQLITE_BIG_DBL/((double)2))<rCost ){
+    pCost->rCost = (SQLITE_BIG_DBL/((double)2));
+  }else{
+    pCost->rCost = rCost;
+  }
+  pCost->plan.u.pVtabIdx = pIdxInfo;
+  if( pIdxInfo->orderByConsumed ){
+    pCost->plan.wsFlags |= WHERE_ORDERBY;
+  }
+  pCost->plan.nEq = 0;
+  pIdxInfo->nOrderBy = nOrderBy;
+
+  /* Try to find a more efficient access pattern by using multiple indexes
+  ** to optimize an OR expression within the WHERE clause. 
+  */
+  bestOrClauseIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost);
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
+#ifdef SQLITE_ENABLE_STAT3
 /*
-** Find the query plan for accessing a particular table.  Write the
+** Estimate the location of a particular key among all keys in an
+** index.  Store the results in aStat as follows:
+**
+**    aStat[0]      Est. number of rows less than pVal
+**    aStat[1]      Est. number of rows equal to pVal
+**
+** Return SQLITE_OK on success.
+*/
+static int whereKeyStats(
+  Parse *pParse,              /* Database connection */
+  Index *pIdx,                /* Index to consider domain of */
+  sqlite3_value *pVal,        /* Value to consider */
+  int roundUp,                /* Round up if true.  Round down if false */
+  tRowcnt *aStat              /* OUT: stats written here */
+){
+  tRowcnt n;
+  IndexSample *aSample;
+  int i, eType;
+  int isEq = 0;
+  i64 v;
+  double r, rS;
+
+  assert( roundUp==0 || roundUp==1 );
+  assert( pIdx->nSample>0 );
+  if( pVal==0 ) return SQLITE_ERROR;
+  n = pIdx->aiRowEst[0];
+  aSample = pIdx->aSample;
+  eType = sqlite3_value_type(pVal);
+
+  if( eType==SQLITE_INTEGER ){
+    v = sqlite3_value_int64(pVal);
+    r = (i64)v;
+    for(i=0; i<pIdx->nSample; i++){
+      if( aSample[i].eType==SQLITE_NULL ) continue;
+      if( aSample[i].eType>=SQLITE_TEXT ) break;
+      if( aSample[i].eType==SQLITE_INTEGER ){
+        if( aSample[i].u.i>=v ){
+          isEq = aSample[i].u.i==v;
+          break;
+        }
+      }else{
+        assert( aSample[i].eType==SQLITE_FLOAT );
+        if( aSample[i].u.r>=r ){
+          isEq = aSample[i].u.r==r;
+          break;
+        }
+      }
+    }
+  }else if( eType==SQLITE_FLOAT ){
+    r = sqlite3_value_double(pVal);
+    for(i=0; i<pIdx->nSample; i++){
+      if( aSample[i].eType==SQLITE_NULL ) continue;
+      if( aSample[i].eType>=SQLITE_TEXT ) break;
+      if( aSample[i].eType==SQLITE_FLOAT ){
+        rS = aSample[i].u.r;
+      }else{
+        rS = aSample[i].u.i;
+      }
+      if( rS>=r ){
+        isEq = rS==r;
+        break;
+      }
+    }
+  }else if( eType==SQLITE_NULL ){
+    i = 0;
+    if( aSample[0].eType==SQLITE_NULL ) isEq = 1;
+  }else{
+    assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+    for(i=0; i<pIdx->nSample; i++){
+      if( aSample[i].eType==SQLITE_TEXT || aSample[i].eType==SQLITE_BLOB ){
+        break;
+      }
+    }
+    if( i<pIdx->nSample ){      
+      sqlite3 *db = pParse->db;
+      CollSeq *pColl;
+      const u8 *z;
+      if( eType==SQLITE_BLOB ){
+        z = (const u8 *)sqlite3_value_blob(pVal);
+        pColl = db->pDfltColl;
+        assert( pColl->enc==SQLITE_UTF8 );
+      }else{
+        pColl = sqlite3GetCollSeq(db, SQLITE_UTF8, 0, *pIdx->azColl);
+        if( pColl==0 ){
+          sqlite3ErrorMsg(pParse, "no such collation sequence: %s",
+                          *pIdx->azColl);
+          return SQLITE_ERROR;
+        }
+        z = (const u8 *)sqlite3ValueText(pVal, pColl->enc);
+        if( !z ){
+          return SQLITE_NOMEM;
+        }
+        assert( z && pColl && pColl->xCmp );
+      }
+      n = sqlite3ValueBytes(pVal, pColl->enc);
+  
+      for(; i<pIdx->nSample; i++){
+        int c;
+        int eSampletype = aSample[i].eType;
+        if( eSampletype<eType ) continue;
+        if( eSampletype!=eType ) break;
+#ifndef SQLITE_OMIT_UTF16
+        if( pColl->enc!=SQLITE_UTF8 ){
+          int nSample;
+          char *zSample = sqlite3Utf8to16(
+              db, pColl->enc, aSample[i].u.z, aSample[i].nByte, &nSample
+          );
+          if( !zSample ){
+            assert( db->mallocFailed );
+            return SQLITE_NOMEM;
+          }
+          c = pColl->xCmp(pColl->pUser, nSample, zSample, n, z);
+          sqlite3DbFree(db, zSample);
+        }else
+#endif
+        {
+          c = pColl->xCmp(pColl->pUser, aSample[i].nByte, aSample[i].u.z, n, z);
+        }
+        if( c>=0 ){
+          if( c==0 ) isEq = 1;
+          break;
+        }
+      }
+    }
+  }
+
+  /* At this point, aSample[i] is the first sample that is greater than
+  ** or equal to pVal.  Or if i==pIdx->nSample, then all samples are less
+  ** than pVal.  If aSample[i]==pVal, then isEq==1.
+  */
+  if( isEq ){
+    assert( i<pIdx->nSample );
+    aStat[0] = aSample[i].nLt;
+    aStat[1] = aSample[i].nEq;
+  }else{
+    tRowcnt iLower, iUpper, iGap;
+    if( i==0 ){
+      iLower = 0;
+      iUpper = aSample[0].nLt;
+    }else{
+      iUpper = i>=pIdx->nSample ? n : aSample[i].nLt;
+      iLower = aSample[i-1].nEq + aSample[i-1].nLt;
+    }
+    aStat[1] = pIdx->avgEq;
+    if( iLower>=iUpper ){
+      iGap = 0;
+    }else{
+      iGap = iUpper - iLower;
+    }
+    if( roundUp ){
+      iGap = (iGap*2)/3;
+    }else{
+      iGap = iGap/3;
+    }
+    aStat[0] = iLower + iGap;
+  }
+  return SQLITE_OK;
+}
+#endif /* SQLITE_ENABLE_STAT3 */
+
+/*
+** If expression pExpr represents a literal value, set *pp to point to
+** an sqlite3_value structure containing the same value, with affinity
+** aff applied to it, before returning. It is the responsibility of the 
+** caller to eventually release this structure by passing it to 
+** sqlite3ValueFree().
+**
+** If the current parse is a recompile (sqlite3Reprepare()) and pExpr
+** is an SQL variable that currently has a non-NULL value bound to it,
+** create an sqlite3_value structure containing this value, again with
+** affinity aff applied to it, instead.
+**
+** If neither of the above apply, set *pp to NULL.
+**
+** If an error occurs, return an error code. Otherwise, SQLITE_OK.
+*/
+#ifdef SQLITE_ENABLE_STAT3
+static int valueFromExpr(
+  Parse *pParse, 
+  Expr *pExpr, 
+  u8 aff, 
+  sqlite3_value **pp
+){
+  if( pExpr->op==TK_VARIABLE
+   || (pExpr->op==TK_REGISTER && pExpr->op2==TK_VARIABLE)
+  ){
+    int iVar = pExpr->iColumn;
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iVar);
+    *pp = sqlite3VdbeGetValue(pParse->pReprepare, iVar, aff);
+    return SQLITE_OK;
+  }
+  return sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, aff, pp);
+}
+#endif
+
+/*
+** This function is used to estimate the number of rows that will be visited
+** by scanning an index for a range of values. The range may have an upper
+** bound, a lower bound, or both. The WHERE clause terms that set the upper
+** and lower bounds are represented by pLower and pUpper respectively. For
+** example, assuming that index p is on t1(a):
+**
+**   ... FROM t1 WHERE a > ? AND a < ? ...
+**                    |_____|   |_____|
+**                       |         |
+**                     pLower    pUpper
+**
+** If either of the upper or lower bound is not present, then NULL is passed in
+** place of the corresponding WhereTerm.
+**
+** The nEq parameter is passed the index of the index column subject to the
+** range constraint. Or, equivalently, the number of equality constraints
+** optimized by the proposed index scan. For example, assuming index p is
+** on t1(a, b), and the SQL query is:
+**
+**   ... FROM t1 WHERE a = ? AND b > ? AND b < ? ...
+**
+** then nEq should be passed the value 1 (as the range restricted column,
+** b, is the second left-most column of the index). Or, if the query is:
+**
+**   ... FROM t1 WHERE a > ? AND a < ? ...
+**
+** then nEq should be passed 0.
+**
+** The returned value is an integer divisor to reduce the estimated
+** search space.  A return value of 1 means that range constraints are
+** no help at all.  A return value of 2 means range constraints are
+** expected to reduce the search space by half.  And so forth...
+**
+** In the absence of sqlite_stat3 ANALYZE data, each range inequality
+** reduces the search space by a factor of 4.  Hence a single constraint (x>?)
+** results in a return of 4 and a range constraint (x>? AND x<?) results
+** in a return of 16.
+*/
+static int whereRangeScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  Index *p,            /* The index containing the range-compared column; "x" */
+  int nEq,             /* index into p->aCol[] of the range-compared column */
+  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
+  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
+  double *pRangeDiv   /* OUT: Reduce search space by this divisor */
+){
+  int rc = SQLITE_OK;
+
+#ifdef SQLITE_ENABLE_STAT3
+
+  if( nEq==0 && p->nSample ){
+    sqlite3_value *pRangeVal;
+    tRowcnt iLower = 0;
+    tRowcnt iUpper = p->aiRowEst[0];
+    tRowcnt a[2];
+    u8 aff = p->pTable->aCol[p->aiColumn[0]].affinity;
+
+    if( pLower ){
+      Expr *pExpr = pLower->pExpr->pRight;
+      rc = valueFromExpr(pParse, pExpr, aff, &pRangeVal);
+      assert( pLower->eOperator==WO_GT || pLower->eOperator==WO_GE );
+      if( rc==SQLITE_OK
+       && whereKeyStats(pParse, p, pRangeVal, 0, a)==SQLITE_OK
+      ){
+        iLower = a[0];
+        if( pLower->eOperator==WO_GT ) iLower += a[1];
+      }
+      sqlite3ValueFree(pRangeVal);
+    }
+    if( rc==SQLITE_OK && pUpper ){
+      Expr *pExpr = pUpper->pExpr->pRight;
+      rc = valueFromExpr(pParse, pExpr, aff, &pRangeVal);
+      assert( pUpper->eOperator==WO_LT || pUpper->eOperator==WO_LE );
+      if( rc==SQLITE_OK
+       && whereKeyStats(pParse, p, pRangeVal, 1, a)==SQLITE_OK
+      ){
+        iUpper = a[0];
+        if( pUpper->eOperator==WO_LE ) iUpper += a[1];
+      }
+      sqlite3ValueFree(pRangeVal);
+    }
+    if( rc==SQLITE_OK ){
+      if( iUpper<=iLower ){
+        *pRangeDiv = (double)p->aiRowEst[0];
+      }else{
+        *pRangeDiv = (double)p->aiRowEst[0]/(double)(iUpper - iLower);
+      }
+      WHERETRACE(("range scan regions: %u..%u  div=%g\n",
+                  (u32)iLower, (u32)iUpper, *pRangeDiv));
+      return SQLITE_OK;
+    }
+  }
+#else
+  UNUSED_PARAMETER(pParse);
+  UNUSED_PARAMETER(p);
+  UNUSED_PARAMETER(nEq);
+#endif
+  assert( pLower || pUpper );
+  *pRangeDiv = (double)1;
+  if( pLower && (pLower->wtFlags & TERM_VNULL)==0 ) *pRangeDiv *= (double)4;
+  if( pUpper ) *pRangeDiv *= (double)4;
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_STAT3
+/*
+** Estimate the number of rows that will be returned based on
+** an equality constraint x=VALUE and where that VALUE occurs in
+** the histogram data.  This only works when x is the left-most
+** column of an index and sqlite_stat3 histogram data is available
+** for that index.  When pExpr==NULL that means the constraint is
+** "x IS NULL" instead of "x=VALUE".
+**
+** Write the estimated row count into *pnRow and return SQLITE_OK. 
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
+**
+** This routine can fail if it is unable to load a collating sequence
+** required for string comparison, or if unable to allocate memory
+** for a UTF conversion required for comparison.  The error is stored
+** in the pParse structure.
+*/
+static int whereEqualScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  Index *p,            /* The index whose left-most column is pTerm */
+  Expr *pExpr,         /* Expression for VALUE in the x=VALUE constraint */
+  double *pnRow        /* Write the revised row estimate here */
+){
+  sqlite3_value *pRhs = 0;  /* VALUE on right-hand side of pTerm */
+  u8 aff;                   /* Column affinity */
+  int rc;                   /* Subfunction return code */
+  tRowcnt a[2];             /* Statistics */
+
+  assert( p->aSample!=0 );
+  assert( p->nSample>0 );
+  aff = p->pTable->aCol[p->aiColumn[0]].affinity;
+  if( pExpr ){
+    rc = valueFromExpr(pParse, pExpr, aff, &pRhs);
+    if( rc ) goto whereEqualScanEst_cancel;
+  }else{
+    pRhs = sqlite3ValueNew(pParse->db);
+  }
+  if( pRhs==0 ) return SQLITE_NOTFOUND;
+  rc = whereKeyStats(pParse, p, pRhs, 0, a);
+  if( rc==SQLITE_OK ){
+    WHERETRACE(("equality scan regions: %d\n", (int)a[1]));
+    *pnRow = a[1];
+  }
+whereEqualScanEst_cancel:
+  sqlite3ValueFree(pRhs);
+  return rc;
+}
+#endif /* defined(SQLITE_ENABLE_STAT3) */
+
+#ifdef SQLITE_ENABLE_STAT3
+/*
+** Estimate the number of rows that will be returned based on
+** an IN constraint where the right-hand side of the IN operator
+** is a list of values.  Example:
+**
+**        WHERE x IN (1,2,3,4)
+**
+** Write the estimated row count into *pnRow and return SQLITE_OK. 
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
+**
+** This routine can fail if it is unable to load a collating sequence
+** required for string comparison, or if unable to allocate memory
+** for a UTF conversion required for comparison.  The error is stored
+** in the pParse structure.
+*/
+static int whereInScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  Index *p,            /* The index whose left-most column is pTerm */
+  ExprList *pList,     /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
+  double *pnRow        /* Write the revised row estimate here */
+){
+  int rc = SQLITE_OK;         /* Subfunction return code */
+  double nEst;                /* Number of rows for a single term */
+  double nRowEst = (double)0; /* New estimate of the number of rows */
+  int i;                      /* Loop counter */
+
+  assert( p->aSample!=0 );
+  for(i=0; rc==SQLITE_OK && i<pList->nExpr; i++){
+    nEst = p->aiRowEst[0];
+    rc = whereEqualScanEst(pParse, p, pList->a[i].pExpr, &nEst);
+    nRowEst += nEst;
+  }
+  if( rc==SQLITE_OK ){
+    if( nRowEst > p->aiRowEst[0] ) nRowEst = p->aiRowEst[0];
+    *pnRow = nRowEst;
+    WHERETRACE(("IN row estimate: est=%g\n", nRowEst));
+  }
+  return rc;
+}
+#endif /* defined(SQLITE_ENABLE_STAT3) */
+
+
+/*
+** Find the best query plan for accessing a particular table.  Write the
 ** best query plan and its cost into the WhereCost object supplied as the
 ** last parameter.
 **
 ** The lowest cost plan wins.  The cost is an estimate of the amount of
-** CPU and disk I/O need to process the request using the selected plan.
+** CPU and disk I/O needed to process the requested result.
 ** Factors that influence cost include:
 **
 **    *  The estimated number of rows that will be retrieved.  (The
@@ -81164,319 +104522,525 @@ static double bestVirtualIndex(
 **    *  Whether or not there must be separate lookups in the
 **       index and in the main table.
 **
-** If there was an INDEXED BY clause attached to the table in the SELECT
-** statement, then this function only considers plans using the 
-** named index. If one cannot be found, then the returned cost is
-** SQLITE_BIG_DBL. If a plan can be found that uses the named index, 
+** If there was an INDEXED BY clause (pSrc->pIndex) attached to the table in
+** the SQL statement, then this function only considers plans using the 
+** named index. If no such plan is found, then the returned cost is
+** SQLITE_BIG_DBL. If a plan is found that uses the named index, 
 ** then the cost is calculated in the usual way.
 **
-** If a NOT INDEXED clause was attached to the table in the SELECT 
-** statement, then no indexes are considered. However, the selected 
-** plan may still take advantage of the tables built-in rowid
+** If a NOT INDEXED clause (pSrc->notIndexed!=0) was attached to the table 
+** in the SELECT statement, then no indexes are considered. However, the 
+** selected plan may still take advantage of the built-in rowid primary key
 ** index.
 */
-static void bestIndex(
+static void bestBtreeIndex(
   Parse *pParse,              /* The parsing context */
   WhereClause *pWC,           /* The WHERE clause */
   struct SrcList_item *pSrc,  /* The FROM clause term to search */
-  Bitmask notReady,           /* Mask of cursors that are not available */
+  Bitmask notReady,           /* Mask of cursors not available for indexing */
+  Bitmask notValid,           /* Cursors not available for any purpose */
   ExprList *pOrderBy,         /* The ORDER BY clause */
+  ExprList *pDistinct,        /* The select-list if query is DISTINCT */
   WhereCost *pCost            /* Lowest cost query plan */
 ){
-  WhereTerm *pTerm;           /* A single term of the WHERE clause */
   int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
   Index *pProbe;              /* An index we are evaluating */
-  int rev;                    /* True to scan in reverse order */
-  int wsFlags;                /* Flags associated with pProbe */
-  int nEq;                    /* Number of == or IN constraints */
-  int eqTermMask;             /* Mask of valid equality operators */
-  double cost;                /* Cost of using pProbe */
-  double nRow;                /* Estimated number of rows in result set */
-  int i;                      /* Loop counter */
-  Bitmask maskSrc;            /* Bitmask for the pSrc table */
+  Index *pIdx;                /* Copy of pProbe, or zero for IPK index */
+  int eqTermMask;             /* Current mask of valid equality operators */
+  int idxEqTermMask;          /* Index mask of valid equality operators */
+  Index sPk;                  /* A fake index object for the primary key */
+  tRowcnt aiRowEstPk[2];      /* The aiRowEst[] value for the sPk index */
+  int aiColumnPk = -1;        /* The aColumn[] value for the sPk index */
+  int wsFlagMask;             /* Allowed flags in pCost->plan.wsFlag */
 
-  WHERETRACE(("bestIndex: tbl=%s notReady=%llx\n", pSrc->pTab->zName,notReady));
-  pProbe = pSrc->pTab->pIndex;
-  if( pSrc->notIndexed ){
-    pProbe = 0;
-  }
-
-  /* If the table has no indices and there are no terms in the where
-  ** clause that refer to the ROWID, then we will never be able to do
-  ** anything other than a full table scan on this table.  We might as
-  ** well put it first in the join order.  That way, perhaps it can be
-  ** referenced by other tables in the join.
-  */
+  /* Initialize the cost to a worst-case value */
   memset(pCost, 0, sizeof(*pCost));
-  if( pProbe==0 &&
-     findTerm(pWC, iCur, -1, 0, WO_EQ|WO_IN|WO_LT|WO_LE|WO_GT|WO_GE,0)==0 &&
-     (pOrderBy==0 || !sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev)) ){
-    return;
-  }
   pCost->rCost = SQLITE_BIG_DBL;
 
-  /* Check for a rowid=EXPR or rowid IN (...) constraints. If there was
-  ** an INDEXED BY clause attached to this table, skip this step.
-  */
-  if( !pSrc->pIndex ){
-    pTerm = findTerm(pWC, iCur, -1, notReady, WO_EQ|WO_IN, 0);
-    if( pTerm ){
-      Expr *pExpr;
-      pCost->plan.wsFlags = WHERE_ROWID_EQ;
-      if( pTerm->eOperator & WO_EQ ){
-        /* Rowid== is always the best pick.  Look no further.  Because only
-        ** a single row is generated, output is always in sorted order */
-        pCost->plan.wsFlags = WHERE_ROWID_EQ | WHERE_UNIQUE;
-        pCost->plan.nEq = 1;
-        WHERETRACE(("... best is rowid\n"));
-        pCost->rCost = 0;
-        pCost->nRow = 1;
-        return;
-      }else if( (pExpr = pTerm->pExpr)->pList!=0 ){
-        /* Rowid IN (LIST): cost is NlogN where N is the number of list
-        ** elements.  */
-        pCost->rCost = pCost->nRow = pExpr->pList->nExpr;
-        pCost->rCost *= estLog(pCost->rCost);
-      }else{
-        /* Rowid IN (SELECT): cost is NlogN where N is the number of rows
-        ** in the result of the inner select.  We have no way to estimate
-        ** that value so make a wild guess. */
-        pCost->nRow = 100;
-        pCost->rCost = 200;
-      }
-      WHERETRACE(("... rowid IN cost: %.9g\n", pCost->rCost));
-    }
-  
-    /* Estimate the cost of a table scan.  If we do not know how many
-    ** entries are in the table, use 1 million as a guess.
-    */
-    cost = pProbe ? pProbe->aiRowEst[0] : 1000000;
-    WHERETRACE(("... table scan base cost: %.9g\n", cost));
-    wsFlags = WHERE_ROWID_RANGE;
-  
-    /* Check for constraints on a range of rowids in a table scan.
-    */
-    pTerm = findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE|WO_GT|WO_GE, 0);
-    if( pTerm ){
-      if( findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE, 0) ){
-        wsFlags |= WHERE_TOP_LIMIT;
-        cost /= 3;  /* Guess that rowid<EXPR eliminates two-thirds of rows */
-      }
-      if( findTerm(pWC, iCur, -1, notReady, WO_GT|WO_GE, 0) ){
-        wsFlags |= WHERE_BTM_LIMIT;
-        cost /= 3;  /* Guess that rowid>EXPR eliminates two-thirds of rows */
-      }
-      WHERETRACE(("... rowid range reduces cost to %.9g\n", cost));
-    }else{
-      wsFlags = 0;
-    }
-    nRow = cost;
-  
-    /* If the table scan does not satisfy the ORDER BY clause, increase
-    ** the cost by NlogN to cover the expense of sorting. */
-    if( pOrderBy ){
-      if( sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev) ){
-        wsFlags |= WHERE_ORDERBY|WHERE_ROWID_RANGE;
-        if( rev ){
-          wsFlags |= WHERE_REVERSE;
-        }
-      }else{
-        cost += cost*estLog(cost);
-        WHERETRACE(("... sorting increases cost to %.9g\n", cost));
-      }
-    }
-    if( cost<pCost->rCost ){
-      pCost->rCost = cost;
-      pCost->nRow = nRow;
-      pCost->plan.wsFlags = wsFlags;
-    }
-  }
-
-#ifndef SQLITE_OMIT_OR_OPTIMIZATION
-  /* Search for an OR-clause that can be used to look up the table.
-  */
-  maskSrc = getMask(pWC->pMaskSet, iCur);
-  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
-    WhereClause tempWC;
-    tempWC = *pWC;
-    if( pTerm->eOperator==WO_OR 
-        && ((pTerm->prereqAll & ~maskSrc) & notReady)==0
-        && (pTerm->u.pOrInfo->indexable & maskSrc)!=0 ){
-      WhereClause *pOrWC = &pTerm->u.pOrInfo->wc;
-      WhereTerm *pOrTerm;
-      int j;
-      int sortable = 0;
-      double rTotal = 0;
-      nRow = 0;
-      for(j=0, pOrTerm=pOrWC->a; j<pOrWC->nTerm; j++, pOrTerm++){
-        WhereCost sTermCost;
-        WHERETRACE(("... Multi-index OR testing for term %d of %d....\n", j,i));
-        if( pOrTerm->eOperator==WO_AND ){
-          WhereClause *pAndWC = &pOrTerm->u.pAndInfo->wc;
-          bestIndex(pParse, pAndWC, pSrc, notReady, 0, &sTermCost);
-        }else if( pOrTerm->leftCursor==iCur ){
-          tempWC.a = pOrTerm;
-          tempWC.nTerm = 1;
-          bestIndex(pParse, &tempWC, pSrc, notReady, 0, &sTermCost);
-        }else{
-          continue;
-        }
-        rTotal += sTermCost.rCost;
-        nRow += sTermCost.nRow;
-        if( rTotal>=pCost->rCost ) break;
-      }
-      if( pOrderBy!=0 ){
-        if( sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev) && !rev ){
-          sortable = 1;
-        }else{
-          rTotal += nRow*estLog(nRow);
-          WHERETRACE(("... sorting increases OR cost to %.9g\n", rTotal));
-        }
-      }
-      WHERETRACE(("... multi-index OR cost=%.9g nrow=%.9g\n",
-                  rTotal, nRow));
-      if( rTotal<pCost->rCost ){
-        pCost->rCost = rTotal;
-        pCost->nRow = nRow;
-        pCost->plan.wsFlags = WHERE_MULTI_OR;
-        pCost->plan.u.pTerm = pTerm;
-        if( sortable ){
-          pCost->plan.wsFlags = WHERE_ORDERBY|WHERE_MULTI_OR;
-        }
-      }
-    }
-  }
-#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
-
   /* If the pSrc table is the right table of a LEFT JOIN then we may not
   ** use an index to satisfy IS NULL constraints on that table.  This is
   ** because columns might end up being NULL if the table does not match -
   ** a circumstance which the index cannot help us discover.  Ticket #2177.
   */
-  if( (pSrc->jointype & JT_LEFT)!=0 ){
-    eqTermMask = WO_EQ|WO_IN;
+  if( pSrc->jointype & JT_LEFT ){
+    idxEqTermMask = WO_EQ|WO_IN;
   }else{
-    eqTermMask = WO_EQ|WO_IN|WO_ISNULL;
+    idxEqTermMask = WO_EQ|WO_IN|WO_ISNULL;
   }
 
-  /* Look at each index.
-  */
   if( pSrc->pIndex ){
-    pProbe = pSrc->pIndex;
+    /* An INDEXED BY clause specifies a particular index to use */
+    pIdx = pProbe = pSrc->pIndex;
+    wsFlagMask = ~(WHERE_ROWID_EQ|WHERE_ROWID_RANGE);
+    eqTermMask = idxEqTermMask;
+  }else{
+    /* There is no INDEXED BY clause.  Create a fake Index object in local
+    ** variable sPk to represent the rowid primary key index.  Make this
+    ** fake index the first in a chain of Index objects with all of the real
+    ** indices to follow */
+    Index *pFirst;                  /* First of real indices on the table */
+    memset(&sPk, 0, sizeof(Index));
+    sPk.nColumn = 1;
+    sPk.aiColumn = &aiColumnPk;
+    sPk.aiRowEst = aiRowEstPk;
+    sPk.onError = OE_Replace;
+    sPk.pTable = pSrc->pTab;
+    aiRowEstPk[0] = pSrc->pTab->nRowEst;
+    aiRowEstPk[1] = 1;
+    pFirst = pSrc->pTab->pIndex;
+    if( pSrc->notIndexed==0 ){
+      /* The real indices of the table are only considered if the
+      ** NOT INDEXED qualifier is omitted from the FROM clause */
+      sPk.pNext = pFirst;
+    }
+    pProbe = &sPk;
+    wsFlagMask = ~(
+        WHERE_COLUMN_IN|WHERE_COLUMN_EQ|WHERE_COLUMN_NULL|WHERE_COLUMN_RANGE
+    );
+    eqTermMask = WO_EQ|WO_IN;
+    pIdx = 0;
   }
-  for(; pProbe; pProbe=(pSrc->pIndex ? 0 : pProbe->pNext)){
-    double inMultiplier = 1;
 
-    WHERETRACE(("... index %s:\n", pProbe->zName));
+  /* Loop over all indices looking for the best one to use
+  */
+  for(; pProbe; pIdx=pProbe=pProbe->pNext){
+    const tRowcnt * const aiRowEst = pProbe->aiRowEst;
+    double cost;                /* Cost of using pProbe */
+    double nRow;                /* Estimated number of rows in result set */
+    double log10N = (double)1;  /* base-10 logarithm of nRow (inexact) */
+    int rev;                    /* True to scan in reverse order */
+    int wsFlags = 0;
+    Bitmask used = 0;
 
-    /* Count the number of columns in the index that are satisfied
-    ** by x=EXPR constraints or x IN (...) constraints.
+    /* The following variables are populated based on the properties of
+    ** index being evaluated. They are then used to determine the expected
+    ** cost and number of rows returned.
+    **
+    **  nEq: 
+    **    Number of equality terms that can be implemented using the index.
+    **    In other words, the number of initial fields in the index that
+    **    are used in == or IN or NOT NULL constraints of the WHERE clause.
+    **
+    **  nInMul:  
+    **    The "in-multiplier". This is an estimate of how many seek operations 
+    **    SQLite must perform on the index in question. For example, if the 
+    **    WHERE clause is:
+    **
+    **      WHERE a IN (1, 2, 3) AND b IN (4, 5, 6)
+    **
+    **    SQLite must perform 9 lookups on an index on (a, b), so nInMul is 
+    **    set to 9. Given the same schema and either of the following WHERE 
+    **    clauses:
+    **
+    **      WHERE a =  1
+    **      WHERE a >= 2
+    **
+    **    nInMul is set to 1.
+    **
+    **    If there exists a WHERE term of the form "x IN (SELECT ...)", then 
+    **    the sub-select is assumed to return 25 rows for the purposes of 
+    **    determining nInMul.
+    **
+    **  bInEst:  
+    **    Set to true if there was at least one "x IN (SELECT ...)" term used 
+    **    in determining the value of nInMul.  Note that the RHS of the
+    **    IN operator must be a SELECT, not a value list, for this variable
+    **    to be true.
+    **
+    **  rangeDiv:
+    **    An estimate of a divisor by which to reduce the search space due
+    **    to inequality constraints.  In the absence of sqlite_stat3 ANALYZE
+    **    data, a single inequality reduces the search space to 1/4rd its
+    **    original size (rangeDiv==4).  Two inequalities reduce the search
+    **    space to 1/16th of its original size (rangeDiv==16).
+    **
+    **  bSort:   
+    **    Boolean. True if there is an ORDER BY clause that will require an 
+    **    external sort (i.e. scanning the index being evaluated will not 
+    **    correctly order records).
+    **
+    **  bLookup: 
+    **    Boolean. True if a table lookup is required for each index entry
+    **    visited.  In other words, true if this is not a covering index.
+    **    This is always false for the rowid primary key index of a table.
+    **    For other indexes, it is true unless all the columns of the table
+    **    used by the SELECT statement are present in the index (such an
+    **    index is sometimes described as a covering index).
+    **    For example, given the index on (a, b), the second of the following 
+    **    two queries requires table b-tree lookups in order to find the value
+    **    of column c, but the first does not because columns a and b are
+    **    both available in the index.
+    **
+    **             SELECT a, b    FROM tbl WHERE a = 1;
+    **             SELECT a, b, c FROM tbl WHERE a = 1;
     */
-    wsFlags = 0;
-    for(i=0; i<pProbe->nColumn; i++){
-      int j = pProbe->aiColumn[i];
-      pTerm = findTerm(pWC, iCur, j, notReady, eqTermMask, pProbe);
+    int nEq;                      /* Number of == or IN terms matching index */
+    int bInEst = 0;               /* True if "x IN (SELECT...)" seen */
+    int nInMul = 1;               /* Number of distinct equalities to lookup */
+    double rangeDiv = (double)1;  /* Estimated reduction in search space */
+    int nBound = 0;               /* Number of range constraints seen */
+    int bSort = !!pOrderBy;       /* True if external sort required */
+    int bDist = !!pDistinct;      /* True if index cannot help with DISTINCT */
+    int bLookup = 0;              /* True if not a covering index */
+    WhereTerm *pTerm;             /* A single term of the WHERE clause */
+#ifdef SQLITE_ENABLE_STAT3
+    WhereTerm *pFirstTerm = 0;    /* First term matching the index */
+#endif
+
+    /* Determine the values of nEq and nInMul */
+    for(nEq=0; nEq<pProbe->nColumn; nEq++){
+      int j = pProbe->aiColumn[nEq];
+      pTerm = findTerm(pWC, iCur, j, notReady, eqTermMask, pIdx);
       if( pTerm==0 ) break;
-      wsFlags |= WHERE_COLUMN_EQ;
+      wsFlags |= (WHERE_COLUMN_EQ|WHERE_ROWID_EQ);
+      testcase( pTerm->pWC!=pWC );
       if( pTerm->eOperator & WO_IN ){
         Expr *pExpr = pTerm->pExpr;
         wsFlags |= WHERE_COLUMN_IN;
-        if( pExpr->pSelect!=0 ){
-          inMultiplier *= 25;
-        }else if( ALWAYS(pExpr->pList) ){
-          inMultiplier *= pExpr->pList->nExpr + 1;
+        if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+          /* "x IN (SELECT ...)":  Assume the SELECT returns 25 rows */
+          nInMul *= 25;
+          bInEst = 1;
+        }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
+          /* "x IN (value, value, ...)" */
+          nInMul *= pExpr->x.pList->nExpr;
         }
+      }else if( pTerm->eOperator & WO_ISNULL ){
+        wsFlags |= WHERE_COLUMN_NULL;
       }
+#ifdef SQLITE_ENABLE_STAT3
+      if( nEq==0 && pProbe->aSample ) pFirstTerm = pTerm;
+#endif
+      used |= pTerm->prereqRight;
     }
-    nRow = pProbe->aiRowEst[i] * inMultiplier;
-    cost = nRow * estLog(inMultiplier);
-    nEq = i;
-    if( pProbe->onError!=OE_None && (wsFlags & WHERE_COLUMN_IN)==0
-         && nEq==pProbe->nColumn ){
-      wsFlags |= WHERE_UNIQUE;
-    }
-    WHERETRACE(("...... nEq=%d inMult=%.9g cost=%.9g\n",nEq,inMultiplier,cost));
-
-    /* Look for range constraints
+ 
+    /* If the index being considered is UNIQUE, and there is an equality 
+    ** constraint for all columns in the index, then this search will find
+    ** at most a single row. In this case set the WHERE_UNIQUE flag to 
+    ** indicate this to the caller.
+    **
+    ** Otherwise, if the search may find more than one row, test to see if
+    ** there is a range constraint on indexed column (nEq+1) that can be 
+    ** optimized using the index. 
     */
-    if( nEq<pProbe->nColumn ){
-      int j = pProbe->aiColumn[nEq];
-      pTerm = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pProbe);
-      if( pTerm ){
-        wsFlags |= WHERE_COLUMN_RANGE;
-        if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe) ){
+    if( nEq==pProbe->nColumn && pProbe->onError!=OE_None ){
+      testcase( wsFlags & WHERE_COLUMN_IN );
+      testcase( wsFlags & WHERE_COLUMN_NULL );
+      if( (wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_NULL))==0 ){
+        wsFlags |= WHERE_UNIQUE;
+      }
+    }else if( pProbe->bUnordered==0 ){
+      int j = (nEq==pProbe->nColumn ? -1 : pProbe->aiColumn[nEq]);
+      if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pIdx) ){
+        WhereTerm *pTop = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pIdx);
+        WhereTerm *pBtm = findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pIdx);
+        whereRangeScanEst(pParse, pProbe, nEq, pBtm, pTop, &rangeDiv);
+        if( pTop ){
+          nBound = 1;
           wsFlags |= WHERE_TOP_LIMIT;
-          cost /= 3;
-          nRow /= 3;
+          used |= pTop->prereqRight;
+          testcase( pTop->pWC!=pWC );
         }
-        if( findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe) ){
+        if( pBtm ){
+          nBound++;
           wsFlags |= WHERE_BTM_LIMIT;
-          cost /= 3;
-          nRow /= 3;
+          used |= pBtm->prereqRight;
+          testcase( pBtm->pWC!=pWC );
         }
-        WHERETRACE(("...... range reduces cost to %.9g\n", cost));
+        wsFlags |= (WHERE_COLUMN_RANGE|WHERE_ROWID_RANGE);
       }
     }
 
-    /* Add the additional cost of sorting if that is a factor.
-    */
-    if( pOrderBy ){
-      if( (wsFlags & WHERE_COLUMN_IN)==0 &&
-           isSortingIndex(pParse,pWC->pMaskSet,pProbe,iCur,pOrderBy,nEq,&rev) ){
-        if( wsFlags==0 ){
-          wsFlags = WHERE_COLUMN_RANGE;
-        }
-        wsFlags |= WHERE_ORDERBY;
-        if( rev ){
-          wsFlags |= WHERE_REVERSE;
-        }
-      }else{
-        cost += cost*estLog(cost);
-        WHERETRACE(("...... orderby increases cost to %.9g\n", cost));
-      }
+    /* If there is an ORDER BY clause and the index being considered will
+    ** naturally scan rows in the required order, set the appropriate flags
+    ** in wsFlags. Otherwise, if there is an ORDER BY clause but the index
+    ** will scan rows in a different order, set the bSort variable.  */
+    if( isSortingIndex(
+          pParse, pWC->pMaskSet, pProbe, iCur, pOrderBy, nEq, wsFlags, &rev)
+    ){
+      bSort = 0;
+      wsFlags |= WHERE_ROWID_RANGE|WHERE_COLUMN_RANGE|WHERE_ORDERBY;
+      wsFlags |= (rev ? WHERE_REVERSE : 0);
     }
 
-    /* Check to see if we can get away with using just the index without
-    ** ever reading the table.  If that is the case, then halve the
-    ** cost of this index.
-    */
-    if( wsFlags && pSrc->colUsed < (((Bitmask)1)<<(BMS-1)) ){
+    /* If there is a DISTINCT qualifier and this index will scan rows in
+    ** order of the DISTINCT expressions, clear bDist and set the appropriate
+    ** flags in wsFlags. */
+    if( isDistinctIndex(pParse, pWC, pProbe, iCur, pDistinct, nEq)
+     && (wsFlags & WHERE_COLUMN_IN)==0
+    ){
+      bDist = 0;
+      wsFlags |= WHERE_ROWID_RANGE|WHERE_COLUMN_RANGE|WHERE_DISTINCT;
+    }
+
+    /* If currently calculating the cost of using an index (not the IPK
+    ** index), determine if all required column data may be obtained without 
+    ** using the main table (i.e. if the index is a covering
+    ** index for this query). If it is, set the WHERE_IDX_ONLY flag in
+    ** wsFlags. Otherwise, set the bLookup variable to true.  */
+    if( pIdx && wsFlags ){
       Bitmask m = pSrc->colUsed;
       int j;
-      for(j=0; j<pProbe->nColumn; j++){
-        int x = pProbe->aiColumn[j];
+      for(j=0; j<pIdx->nColumn; j++){
+        int x = pIdx->aiColumn[j];
         if( x<BMS-1 ){
           m &= ~(((Bitmask)1)<<x);
         }
       }
       if( m==0 ){
         wsFlags |= WHERE_IDX_ONLY;
-        cost /= 2;
-        WHERETRACE(("...... idx-only reduces cost to %.9g\n", cost));
+      }else{
+        bLookup = 1;
       }
     }
 
-    /* If this index has achieved the lowest cost so far, then use it.
+    /*
+    ** Estimate the number of rows of output.  For an "x IN (SELECT...)"
+    ** constraint, do not let the estimate exceed half the rows in the table.
     */
-    if( wsFlags!=0 && cost < pCost->rCost ){
-      pCost->rCost = cost;
-      pCost->nRow = nRow;
-      pCost->plan.wsFlags = wsFlags;
-      pCost->plan.nEq = nEq;
-      assert( pCost->plan.wsFlags & WHERE_INDEXED );
-      pCost->plan.u.pIdx = pProbe;
+    nRow = (double)(aiRowEst[nEq] * nInMul);
+    if( bInEst && nRow*2>aiRowEst[0] ){
+      nRow = aiRowEst[0]/2;
+      nInMul = (int)(nRow / aiRowEst[nEq]);
     }
+
+#ifdef SQLITE_ENABLE_STAT3
+    /* If the constraint is of the form x=VALUE or x IN (E1,E2,...)
+    ** and we do not think that values of x are unique and if histogram
+    ** data is available for column x, then it might be possible
+    ** to get a better estimate on the number of rows based on
+    ** VALUE and how common that value is according to the histogram.
+    */
+    if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 && aiRowEst[1]>1 ){
+      assert( (pFirstTerm->eOperator & (WO_EQ|WO_ISNULL|WO_IN))!=0 );
+      if( pFirstTerm->eOperator & (WO_EQ|WO_ISNULL) ){
+        testcase( pFirstTerm->eOperator==WO_EQ );
+        testcase( pFirstTerm->eOperator==WO_ISNULL );
+        whereEqualScanEst(pParse, pProbe, pFirstTerm->pExpr->pRight, &nRow);
+      }else if( bInEst==0 ){
+        assert( pFirstTerm->eOperator==WO_IN );
+        whereInScanEst(pParse, pProbe, pFirstTerm->pExpr->x.pList, &nRow);
+      }
+    }
+#endif /* SQLITE_ENABLE_STAT3 */
+
+    /* Adjust the number of output rows and downward to reflect rows
+    ** that are excluded by range constraints.
+    */
+    nRow = nRow/rangeDiv;
+    if( nRow<1 ) nRow = 1;
+
+    /* Experiments run on real SQLite databases show that the time needed
+    ** to do a binary search to locate a row in a table or index is roughly
+    ** log10(N) times the time to move from one row to the next row within
+    ** a table or index.  The actual times can vary, with the size of
+    ** records being an important factor.  Both moves and searches are
+    ** slower with larger records, presumably because fewer records fit
+    ** on one page and hence more pages have to be fetched.
+    **
+    ** The ANALYZE command and the sqlite_stat1 and sqlite_stat3 tables do
+    ** not give us data on the relative sizes of table and index records.
+    ** So this computation assumes table records are about twice as big
+    ** as index records
+    */
+    if( (wsFlags & WHERE_NOT_FULLSCAN)==0 ){
+      /* The cost of a full table scan is a number of move operations equal
+      ** to the number of rows in the table.
+      **
+      ** We add an additional 4x penalty to full table scans.  This causes
+      ** the cost function to err on the side of choosing an index over
+      ** choosing a full scan.  This 4x full-scan penalty is an arguable
+      ** decision and one which we expect to revisit in the future.  But
+      ** it seems to be working well enough at the moment.
+      */
+      cost = aiRowEst[0]*4;
+    }else{
+      log10N = estLog(aiRowEst[0]);
+      cost = nRow;
+      if( pIdx ){
+        if( bLookup ){
+          /* For an index lookup followed by a table lookup:
+          **    nInMul index searches to find the start of each index range
+          **  + nRow steps through the index
+          **  + nRow table searches to lookup the table entry using the rowid
+          */
+          cost += (nInMul + nRow)*log10N;
+        }else{
+          /* For a covering index:
+          **     nInMul index searches to find the initial entry 
+          **   + nRow steps through the index
+          */
+          cost += nInMul*log10N;
+        }
+      }else{
+        /* For a rowid primary key lookup:
+        **    nInMult table searches to find the initial entry for each range
+        **  + nRow steps through the table
+        */
+        cost += nInMul*log10N;
+      }
+    }
+
+    /* Add in the estimated cost of sorting the result.  Actual experimental
+    ** measurements of sorting performance in SQLite show that sorting time
+    ** adds C*N*log10(N) to the cost, where N is the number of rows to be 
+    ** sorted and C is a factor between 1.95 and 4.3.  We will split the
+    ** difference and select C of 3.0.
+    */
+    if( bSort ){
+      cost += nRow*estLog(nRow)*3;
+    }
+    if( bDist ){
+      cost += nRow*estLog(nRow)*3;
+    }
+
+    /**** Cost of using this index has now been computed ****/
+
+    /* If there are additional constraints on this table that cannot
+    ** be used with the current index, but which might lower the number
+    ** of output rows, adjust the nRow value accordingly.  This only 
+    ** matters if the current index is the least costly, so do not bother
+    ** with this step if we already know this index will not be chosen.
+    ** Also, never reduce the output row count below 2 using this step.
+    **
+    ** It is critical that the notValid mask be used here instead of
+    ** the notReady mask.  When computing an "optimal" index, the notReady
+    ** mask will only have one bit set - the bit for the current table.
+    ** The notValid mask, on the other hand, always has all bits set for
+    ** tables that are not in outer loops.  If notReady is used here instead
+    ** of notValid, then a optimal index that depends on inner joins loops
+    ** might be selected even when there exists an optimal index that has
+    ** no such dependency.
+    */
+    if( nRow>2 && cost<=pCost->rCost ){
+      int k;                       /* Loop counter */
+      int nSkipEq = nEq;           /* Number of == constraints to skip */
+      int nSkipRange = nBound;     /* Number of < constraints to skip */
+      Bitmask thisTab;             /* Bitmap for pSrc */
+
+      thisTab = getMask(pWC->pMaskSet, iCur);
+      for(pTerm=pWC->a, k=pWC->nTerm; nRow>2 && k; k--, pTerm++){
+        if( pTerm->wtFlags & TERM_VIRTUAL ) continue;
+        if( (pTerm->prereqAll & notValid)!=thisTab ) continue;
+        if( pTerm->eOperator & (WO_EQ|WO_IN|WO_ISNULL) ){
+          if( nSkipEq ){
+            /* Ignore the first nEq equality matches since the index
+            ** has already accounted for these */
+            nSkipEq--;
+          }else{
+            /* Assume each additional equality match reduces the result
+            ** set size by a factor of 10 */
+            nRow /= 10;
+          }
+        }else if( pTerm->eOperator & (WO_LT|WO_LE|WO_GT|WO_GE) ){
+          if( nSkipRange ){
+            /* Ignore the first nSkipRange range constraints since the index
+            ** has already accounted for these */
+            nSkipRange--;
+          }else{
+            /* Assume each additional range constraint reduces the result
+            ** set size by a factor of 3.  Indexed range constraints reduce
+            ** the search space by a larger factor: 4.  We make indexed range
+            ** more selective intentionally because of the subjective 
+            ** observation that indexed range constraints really are more
+            ** selective in practice, on average. */
+            nRow /= 3;
+          }
+        }else if( pTerm->eOperator!=WO_NOOP ){
+          /* Any other expression lowers the output row count by half */
+          nRow /= 2;
+        }
+      }
+      if( nRow<2 ) nRow = 2;
+    }
+
+
+    WHERETRACE((
+      "%s(%s): nEq=%d nInMul=%d rangeDiv=%d bSort=%d bLookup=%d wsFlags=0x%x\n"
+      "         notReady=0x%llx log10N=%.1f nRow=%.1f cost=%.1f used=0x%llx\n",
+      pSrc->pTab->zName, (pIdx ? pIdx->zName : "ipk"), 
+      nEq, nInMul, (int)rangeDiv, bSort, bLookup, wsFlags,
+      notReady, log10N, nRow, cost, used
+    ));
+
+    /* If this index is the best we have seen so far, then record this
+    ** index and its cost in the pCost structure.
+    */
+    if( (!pIdx || wsFlags)
+     && (cost<pCost->rCost || (cost<=pCost->rCost && nRow<pCost->plan.nRow))
+    ){
+      pCost->rCost = cost;
+      pCost->used = used;
+      pCost->plan.nRow = nRow;
+      pCost->plan.wsFlags = (wsFlags&wsFlagMask);
+      pCost->plan.nEq = nEq;
+      pCost->plan.u.pIdx = pIdx;
+    }
+
+    /* If there was an INDEXED BY clause, then only that one index is
+    ** considered. */
+    if( pSrc->pIndex ) break;
+
+    /* Reset masks for the next index in the loop */
+    wsFlagMask = ~(WHERE_ROWID_EQ|WHERE_ROWID_RANGE);
+    eqTermMask = idxEqTermMask;
   }
 
-  /* Report the best result
-  */
+  /* If there is no ORDER BY clause and the SQLITE_ReverseOrder flag
+  ** is set, then reverse the order that the index will be scanned
+  ** in. This is used for application testing, to help find cases
+  ** where application behaviour depends on the (undefined) order that
+  ** SQLite outputs rows in in the absence of an ORDER BY clause.  */
+  if( !pOrderBy && pParse->db->flags & SQLITE_ReverseOrder ){
+    pCost->plan.wsFlags |= WHERE_REVERSE;
+  }
+
+  assert( pOrderBy || (pCost->plan.wsFlags&WHERE_ORDERBY)==0 );
+  assert( pCost->plan.u.pIdx==0 || (pCost->plan.wsFlags&WHERE_ROWID_EQ)==0 );
+  assert( pSrc->pIndex==0 
+       || pCost->plan.u.pIdx==0 
+       || pCost->plan.u.pIdx==pSrc->pIndex 
+  );
+
+  WHERETRACE(("best index is: %s\n", 
+    ((pCost->plan.wsFlags & WHERE_NOT_FULLSCAN)==0 ? "none" : 
+         pCost->plan.u.pIdx ? pCost->plan.u.pIdx->zName : "ipk")
+  ));
+  
+  bestOrClauseIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost);
+  bestAutomaticIndex(pParse, pWC, pSrc, notReady, pCost);
   pCost->plan.wsFlags |= eqTermMask;
-  WHERETRACE(("best index is %s, cost=%.9g, nrow=%.9g, wsFlags=%x, nEq=%d\n",
-        (pCost->plan.wsFlags & WHERE_INDEXED)!=0 ?
-             pCost->plan.u.pIdx->zName : "(none)", pCost->nRow,
-        pCost->rCost, pCost->plan.wsFlags, pCost->plan.nEq));
 }
 
+/*
+** Find the query plan for accessing table pSrc->pTab. Write the
+** best query plan and its cost into the WhereCost object supplied 
+** as the last parameter. This function may calculate the cost of
+** both real and virtual table scans.
+*/
+static void bestIndex(
+  Parse *pParse,              /* The parsing context */
+  WhereClause *pWC,           /* The WHERE clause */
+  struct SrcList_item *pSrc,  /* The FROM clause term to search */
+  Bitmask notReady,           /* Mask of cursors not available for indexing */
+  Bitmask notValid,           /* Cursors not available for any purpose */
+  ExprList *pOrderBy,         /* The ORDER BY clause */
+  WhereCost *pCost            /* Lowest cost query plan */
+){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pSrc->pTab) ){
+    sqlite3_index_info *p = 0;
+    bestVirtualIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost,&p);
+    if( p->needToFreeIdxStr ){
+      sqlite3_free(p->idxStr);
+    }
+    sqlite3DbFree(pParse->db, p);
+  }else
+#endif
+  {
+    bestBtreeIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, 0, pCost);
+  }
+}
 
 /*
 ** Disable a term in the WHERE clause.  Except, do not disable the term
@@ -81493,6 +105057,9 @@ static void bestIndex(
 ** in the ON clause.  The term is disabled in (3) because it is not part
 ** of a LEFT OUTER JOIN.  In (1), the term is not disabled.
 **
+** IMPLEMENTATION-OF: R-24597-58655 No tests are done for terms that are
+** completely satisfied by indices.
+**
 ** Disabling a term causes that term to not be tested in the inner loop
 ** of the join.  Disabling is an optimization.  When terms are satisfied
 ** by indices, we disable them to prevent redundant tests in the inner
@@ -81503,7 +105070,7 @@ static void bestIndex(
 */
 static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){
   if( pTerm
-      && ALWAYS((pTerm->wtFlags & TERM_CODED)==0)
+      && (pTerm->wtFlags & TERM_CODED)==0
       && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_FromJoin))
   ){
     pTerm->wtFlags |= TERM_CODED;
@@ -81517,15 +105084,40 @@ static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){
 }
 
 /*
-** Apply the affinities associated with the first n columns of index
-** pIdx to the values in the n registers starting at base.
+** Code an OP_Affinity opcode to apply the column affinity string zAff
+** to the n registers starting at base. 
+**
+** As an optimization, SQLITE_AFF_NONE entries (which are no-ops) at the
+** beginning and end of zAff are ignored.  If all entries in zAff are
+** SQLITE_AFF_NONE, then no code gets generated.
+**
+** This routine makes its own copy of zAff so that the caller is free
+** to modify zAff after this routine returns.
 */
-static void codeApplyAffinity(Parse *pParse, int base, int n, Index *pIdx){
+static void codeApplyAffinity(Parse *pParse, int base, int n, char *zAff){
+  Vdbe *v = pParse->pVdbe;
+  if( zAff==0 ){
+    assert( pParse->db->mallocFailed );
+    return;
+  }
+  assert( v!=0 );
+
+  /* Adjust base and n to skip over SQLITE_AFF_NONE entries at the beginning
+  ** and end of the affinity string.
+  */
+  while( n>0 && zAff[0]==SQLITE_AFF_NONE ){
+    n--;
+    base++;
+    zAff++;
+  }
+  while( n>1 && zAff[n-1]==SQLITE_AFF_NONE ){
+    n--;
+  }
+
+  /* Code the OP_Affinity opcode if there is anything left to do. */
   if( n>0 ){
-    Vdbe *v = pParse->pVdbe;
-    assert( v!=0 );
     sqlite3VdbeAddOp2(v, OP_Affinity, base, n);
-    sqlite3IndexAffinityStr(v, pIdx);
+    sqlite3VdbeChangeP4(v, -1, zAff, n);
     sqlite3ExprCacheAffinityChange(pParse, base, n);
   }
 }
@@ -81569,7 +105161,6 @@ static int codeEqualityTerm(
     eType = sqlite3FindInIndex(pParse, pX, 0);
     iTab = pX->iTable;
     sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
-    VdbeComment((v, "%.*s", pX->span.n, pX->span.z));
     assert( pLevel->plan.wsFlags & WHERE_IN_ABLE );
     if( pLevel->u.in.nIn==0 ){
       pLevel->addrNxt = sqlite3VdbeMakeLabel(v);
@@ -81599,7 +105190,7 @@ static int codeEqualityTerm(
 
 /*
 ** Generate code that will evaluate all == and IN constraints for an
-** index.  The values for all constraints are left on the stack.
+** index.
 **
 ** For example, consider table t1(a,b,c,d,e,f) with index i1(a,b,c).
 ** Suppose the WHERE clause is this:  a==5 AND b IN (1,2,3) AND c>5 AND c<10
@@ -81611,7 +105202,8 @@ static int codeEqualityTerm(
 **
 ** In the example above nEq==2.  But this subroutine works for any value
 ** of nEq including 0.  If nEq==0, this routine is nearly a no-op.
-** The only thing it does is allocate the pLevel->iMem memory cell.
+** The only thing it does is allocate the pLevel->iMem memory cell and
+** compute the affinity string.
 **
 ** This routine always allocates at least one memory cell and returns
 ** the index of that memory cell. The code that
@@ -81619,13 +105211,29 @@ static int codeEqualityTerm(
 ** key value of the loop.  If one or more IN operators appear, then
 ** this routine allocates an additional nEq memory cells for internal
 ** use.
+**
+** Before returning, *pzAff is set to point to a buffer containing a
+** copy of the column affinity string of the index allocated using
+** sqlite3DbMalloc(). Except, entries in the copy of the string associated
+** with equality constraints that use NONE affinity are set to
+** SQLITE_AFF_NONE. This is to deal with SQL such as the following:
+**
+**   CREATE TABLE t1(a TEXT PRIMARY KEY, b);
+**   SELECT ... FROM t1 AS t2, t1 WHERE t1.a = t2.b;
+**
+** In the example above, the index on t1(a) has TEXT affinity. But since
+** the right hand side of the equality constraint (t2.b) has NONE affinity,
+** no conversion should be attempted before using a t2.b value as part of
+** a key to search the index. Hence the first byte in the returned affinity
+** string in this example would be set to SQLITE_AFF_NONE.
 */
 static int codeAllEqualityTerms(
   Parse *pParse,        /* Parsing context */
   WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
   WhereClause *pWC,     /* The WHERE clause */
   Bitmask notReady,     /* Which parts of FROM have not yet been coded */
-  int nExtraReg         /* Number of extra registers to allocate */
+  int nExtraReg,        /* Number of extra registers to allocate */
+  char **pzAff          /* OUT: Set to point to affinity string */
 ){
   int nEq = pLevel->plan.nEq;   /* The number of == or IN constraints to code */
   Vdbe *v = pParse->pVdbe;      /* The vm under construction */
@@ -81635,6 +105243,7 @@ static int codeAllEqualityTerms(
   int j;                        /* Loop counter */
   int regBase;                  /* Base register */
   int nReg;                     /* Number of registers to allocate */
+  char *zAff;                   /* Affinity string to return */
 
   /* This module is only called on query plans that use an index. */
   assert( pLevel->plan.wsFlags & WHERE_INDEXED );
@@ -81646,6 +105255,11 @@ static int codeAllEqualityTerms(
   nReg = pLevel->plan.nEq + nExtraReg;
   pParse->nMem += nReg;
 
+  zAff = sqlite3DbStrDup(pParse->db, sqlite3IndexAffinityStr(v, pIdx));
+  if( !zAff ){
+    pParse->db->mallocFailed = 1;
+  }
+
   /* Evaluate the equality constraints
   */
   assert( pIdx->nColumn>=nEq );
@@ -81653,8 +105267,11 @@ static int codeAllEqualityTerms(
     int r1;
     int k = pIdx->aiColumn[j];
     pTerm = findTerm(pWC, iCur, k, notReady, pLevel->plan.wsFlags, pIdx);
-    if( NEVER(pTerm==0) ) break;
-    assert( (pTerm->wtFlags & TERM_CODED)==0 );
+    if( pTerm==0 ) break;
+    /* The following true for indices with redundant columns. 
+    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
+    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
+    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
     r1 = codeEqualityTerm(pParse, pTerm, pLevel, regBase+j);
     if( r1!=regBase+j ){
       if( nReg==1 ){
@@ -81667,31 +105284,179 @@ static int codeAllEqualityTerms(
     testcase( pTerm->eOperator & WO_ISNULL );
     testcase( pTerm->eOperator & WO_IN );
     if( (pTerm->eOperator & (WO_ISNULL|WO_IN))==0 ){
-      sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->addrBrk);
+      Expr *pRight = pTerm->pExpr->pRight;
+      sqlite3ExprCodeIsNullJump(v, pRight, regBase+j, pLevel->addrBrk);
+      if( zAff ){
+        if( sqlite3CompareAffinity(pRight, zAff[j])==SQLITE_AFF_NONE ){
+          zAff[j] = SQLITE_AFF_NONE;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zAff[j]) ){
+          zAff[j] = SQLITE_AFF_NONE;
+        }
+      }
     }
   }
+  *pzAff = zAff;
   return regBase;
 }
 
+#ifndef SQLITE_OMIT_EXPLAIN
 /*
-** Return TRUE if the WhereClause pWC contains no terms that
-** are not virtual and which have not been coded.
+** This routine is a helper for explainIndexRange() below
 **
-** To put it another way, return TRUE if no additional WHERE clauses
-** tests are required in order to establish that the current row
-** should go to output and return FALSE if there are some terms of
-** the WHERE clause that need to be validated before outputing the row.
+** pStr holds the text of an expression that we are building up one term
+** at a time.  This routine adds a new term to the end of the expression.
+** Terms are separated by AND so add the "AND" text for second and subsequent
+** terms only.
 */
-static int whereRowReadyForOutput(WhereClause *pWC){
-  WhereTerm *pTerm;
-  int j;
- 
-  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
-    if( (pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED))==0 ) return 0;
-  }
-  return 1;
+static void explainAppendTerm(
+  StrAccum *pStr,             /* The text expression being built */
+  int iTerm,                  /* Index of this term.  First is zero */
+  const char *zColumn,        /* Name of the column */
+  const char *zOp             /* Name of the operator */
+){
+  if( iTerm ) sqlite3StrAccumAppend(pStr, " AND ", 5);
+  sqlite3StrAccumAppend(pStr, zColumn, -1);
+  sqlite3StrAccumAppend(pStr, zOp, 1);
+  sqlite3StrAccumAppend(pStr, "?", 1);
 }
 
+/*
+** Argument pLevel describes a strategy for scanning table pTab. This 
+** function returns a pointer to a string buffer containing a description
+** of the subset of table rows scanned by the strategy in the form of an
+** SQL expression. Or, if all rows are scanned, NULL is returned.
+**
+** For example, if the query:
+**
+**   SELECT * FROM t1 WHERE a=1 AND b>2;
+**
+** is run and there is an index on (a, b), then this function returns a
+** string similar to:
+**
+**   "a=? AND b>?"
+**
+** The returned pointer points to memory obtained from sqlite3DbMalloc().
+** It is the responsibility of the caller to free the buffer when it is
+** no longer required.
+*/
+static char *explainIndexRange(sqlite3 *db, WhereLevel *pLevel, Table *pTab){
+  WherePlan *pPlan = &pLevel->plan;
+  Index *pIndex = pPlan->u.pIdx;
+  int nEq = pPlan->nEq;
+  int i, j;
+  Column *aCol = pTab->aCol;
+  int *aiColumn = pIndex->aiColumn;
+  StrAccum txt;
+
+  if( nEq==0 && (pPlan->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ){
+    return 0;
+  }
+  sqlite3StrAccumInit(&txt, 0, 0, SQLITE_MAX_LENGTH);
+  txt.db = db;
+  sqlite3StrAccumAppend(&txt, " (", 2);
+  for(i=0; i<nEq; i++){
+    explainAppendTerm(&txt, i, aCol[aiColumn[i]].zName, "=");
+  }
+
+  j = i;
+  if( pPlan->wsFlags&WHERE_BTM_LIMIT ){
+    char *z = (j==pIndex->nColumn ) ? "rowid" : aCol[aiColumn[j]].zName;
+    explainAppendTerm(&txt, i++, z, ">");
+  }
+  if( pPlan->wsFlags&WHERE_TOP_LIMIT ){
+    char *z = (j==pIndex->nColumn ) ? "rowid" : aCol[aiColumn[j]].zName;
+    explainAppendTerm(&txt, i, z, "<");
+  }
+  sqlite3StrAccumAppend(&txt, ")", 1);
+  return sqlite3StrAccumFinish(&txt);
+}
+
+/*
+** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
+** command. If the query being compiled is an EXPLAIN QUERY PLAN, a single
+** record is added to the output to describe the table scan strategy in 
+** pLevel.
+*/
+static void explainOneScan(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  int iLevel,                     /* Value for "level" column of output */
+  int iFrom,                      /* Value for "from" column of output */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+){
+  if( pParse->explain==2 ){
+    u32 flags = pLevel->plan.wsFlags;
+    struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom];
+    Vdbe *v = pParse->pVdbe;      /* VM being constructed */
+    sqlite3 *db = pParse->db;     /* Database handle */
+    char *zMsg;                   /* Text to add to EQP output */
+    sqlite3_int64 nRow;           /* Expected number of rows visited by scan */
+    int iId = pParse->iSelectId;  /* Select id (left-most output column) */
+    int isSearch;                 /* True for a SEARCH. False for SCAN. */
+
+    if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return;
+
+    isSearch = (pLevel->plan.nEq>0)
+             || (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0
+             || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));
+
+    zMsg = sqlite3MPrintf(db, "%s", isSearch?"SEARCH":"SCAN");
+    if( pItem->pSelect ){
+      zMsg = sqlite3MAppendf(db, zMsg, "%s SUBQUERY %d", zMsg,pItem->iSelectId);
+    }else{
+      zMsg = sqlite3MAppendf(db, zMsg, "%s TABLE %s", zMsg, pItem->zName);
+    }
+
+    if( pItem->zAlias ){
+      zMsg = sqlite3MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
+    }
+    if( (flags & WHERE_INDEXED)!=0 ){
+      char *zWhere = explainIndexRange(db, pLevel, pItem->pTab);
+      zMsg = sqlite3MAppendf(db, zMsg, "%s USING %s%sINDEX%s%s%s", zMsg, 
+          ((flags & WHERE_TEMP_INDEX)?"AUTOMATIC ":""),
+          ((flags & WHERE_IDX_ONLY)?"COVERING ":""),
+          ((flags & WHERE_TEMP_INDEX)?"":" "),
+          ((flags & WHERE_TEMP_INDEX)?"": pLevel->plan.u.pIdx->zName),
+          zWhere
+      );
+      sqlite3DbFree(db, zWhere);
+    }else if( flags & (WHERE_ROWID_EQ|WHERE_ROWID_RANGE) ){
+      zMsg = sqlite3MAppendf(db, zMsg, "%s USING INTEGER PRIMARY KEY", zMsg);
+
+      if( flags&WHERE_ROWID_EQ ){
+        zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid=?)", zMsg);
+      }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){
+        zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid>? AND rowid<?)", zMsg);
+      }else if( flags&WHERE_BTM_LIMIT ){
+        zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid>?)", zMsg);
+      }else if( flags&WHERE_TOP_LIMIT ){
+        zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid<?)", zMsg);
+      }
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
+      sqlite3_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
+      zMsg = sqlite3MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
+                  pVtabIdx->idxNum, pVtabIdx->idxStr);
+    }
+#endif
+    if( wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX) ){
+      testcase( wctrlFlags & WHERE_ORDERBY_MIN );
+      nRow = 1;
+    }else{
+      nRow = (sqlite3_int64)pLevel->plan.nRow;
+    }
+    zMsg = sqlite3MAppendf(db, zMsg, "%s (~%lld rows)", zMsg, nRow);
+    sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
+  }
+}
+#else
+# define explainOneScan(u,v,w,x,y,z)
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+
 /*
 ** Generate code for the start of the iLevel-th loop in the WHERE clause
 ** implementation described by pWInfo.
@@ -81699,7 +105464,7 @@ static int whereRowReadyForOutput(WhereClause *pWC){
 static Bitmask codeOneLoopStart(
   WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
   int iLevel,          /* Which level of pWInfo->a[] should be coded */
-  u8 wctrlFlags,       /* One of the WHERE_* flags defined in sqliteInt.h */
+  u16 wctrlFlags,      /* One of the WHERE_* flags defined in sqliteInt.h */
   Bitmask notReady     /* Which tables are currently available */
 ){
   int j, k;            /* Loop counters */
@@ -81715,9 +105480,8 @@ static Bitmask codeOneLoopStart(
   struct SrcList_item *pTabItem;  /* FROM clause term being coded */
   int addrBrk;                    /* Jump here to break out of the loop */
   int addrCont;                   /* Jump here to continue with next cycle */
-  int regRowSet;       /* Write rowids to this RowSet if non-negative */
-  int codeRowSetEarly; /* True if index fully constrains the search */
-  
+  int iRowidReg = 0;        /* Rowid is stored in this register, if not zero */
+  int iReleaseReg = 0;      /* Temp register to free before returning */
 
   pParse = pWInfo->pParse;
   v = pParse->pVdbe;
@@ -81726,9 +105490,8 @@ static Bitmask codeOneLoopStart(
   pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
   iCur = pTabItem->iCursor;
   bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;
-  omitTable = (pLevel->plan.wsFlags & WHERE_IDX_ONLY)!=0;
-  regRowSet = pWInfo->regRowSet;
-  codeRowSetEarly = 0;
+  omitTable = (pLevel->plan.wsFlags & WHERE_IDX_ONLY)!=0 
+           && (wctrlFlags & WHERE_FORCE_TABLE)==0;
 
   /* Create labels for the "break" and "continue" instructions
   ** for the current loop.  Jump to addrBrk to break out of a loop.
@@ -81766,21 +105529,18 @@ static Bitmask codeOneLoopStart(
     const struct sqlite3_index_constraint *aConstraint =
                                                 pVtabIdx->aConstraint;
 
+    sqlite3ExprCachePush(pParse);
     iReg = sqlite3GetTempRange(pParse, nConstraint+2);
-    pParse->disableColCache++;
     for(j=1; j<=nConstraint; j++){
       for(k=0; k<nConstraint; k++){
         if( aUsage[k].argvIndex==j ){
           int iTerm = aConstraint[k].iTermOffset;
-          assert( pParse->disableColCache );
           sqlite3ExprCode(pParse, pWC->a[iTerm].pExpr->pRight, iReg+j+1);
           break;
         }
       }
       if( k==nConstraint ) break;
     }
-    assert( pParse->disableColCache );
-    pParse->disableColCache--;
     sqlite3VdbeAddOp2(v, OP_Integer, pVtabIdx->idxNum, iReg);
     sqlite3VdbeAddOp2(v, OP_Integer, j-1, iReg+1);
     sqlite3VdbeAddOp4(v, OP_VFilter, iCur, addrBrk, iReg, pVtabIdx->idxStr,
@@ -81795,12 +105555,8 @@ static Bitmask codeOneLoopStart(
     pLevel->op = OP_VNext;
     pLevel->p1 = iCur;
     pLevel->p2 = sqlite3VdbeCurrentAddr(v);
-    codeRowSetEarly = regRowSet>=0 ? whereRowReadyForOutput(pWC) : 0;
-    if( codeRowSetEarly ){
-      sqlite3VdbeAddOp2(v, OP_VRowid, iCur, iReg);
-      sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, iReg);
-    }
     sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2);
+    sqlite3ExprCachePop(pParse, 1);
   }else
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
@@ -81810,22 +105566,18 @@ static Bitmask codeOneLoopStart(
     **          we reference multiple rows using a "rowid IN (...)"
     **          construct.
     */
-    int r1;
-    int rtmp = sqlite3GetTempReg(pParse);
+    iReleaseReg = sqlite3GetTempReg(pParse);
     pTerm = findTerm(pWC, iCur, -1, notReady, WO_EQ|WO_IN, 0);
     assert( pTerm!=0 );
     assert( pTerm->pExpr!=0 );
     assert( pTerm->leftCursor==iCur );
     assert( omitTable==0 );
-    r1 = codeEqualityTerm(pParse, pTerm, pLevel, rtmp);
+    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
+    iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, iReleaseReg);
     addrNxt = pLevel->addrNxt;
-    sqlite3VdbeAddOp2(v, OP_MustBeInt, r1, addrNxt);
-    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addrNxt, r1);
-    codeRowSetEarly = (pWC->nTerm==1 && regRowSet>=0) ?1:0;
-    if( codeRowSetEarly ){
-      sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, r1);
-    }
-    sqlite3ReleaseTempReg(pParse, rtmp);
+    sqlite3VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt);
+    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addrNxt, iRowidReg);
+    sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
     VdbeComment((v, "pk"));
     pLevel->op = OP_Noop;
   }else if( pLevel->plan.wsFlags & WHERE_ROWID_RANGE ){
@@ -81861,6 +105613,7 @@ static Bitmask codeOneLoopStart(
       assert( TK_LT==TK_GT+2 );      /*  ... of the TK_xx values... */
       assert( TK_GE==TK_GT+3 );      /*  ... is correcct. */
 
+      testcase( pStart->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
       pX = pStart->pExpr;
       assert( pX!=0 );
       assert( pStart->leftCursor==iCur );
@@ -81878,6 +105631,7 @@ static Bitmask codeOneLoopStart(
       pX = pEnd->pExpr;
       assert( pX!=0 );
       assert( pEnd->leftCursor==iCur );
+      testcase( pEnd->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
       memEndValue = ++pParse->nMem;
       sqlite3ExprCode(pParse, pX->pRight, memEndValue);
       if( pX->op==TK_LT || pX->op==TK_GT ){
@@ -81891,19 +105645,17 @@ static Bitmask codeOneLoopStart(
     pLevel->op = bRev ? OP_Prev : OP_Next;
     pLevel->p1 = iCur;
     pLevel->p2 = start;
-    pLevel->p5 = (pStart==0 && pEnd==0) ?1:0;
-    codeRowSetEarly = regRowSet>=0 ? whereRowReadyForOutput(pWC) : 0;
-    if( codeRowSetEarly || testOp!=OP_Noop ){
-      int r1 = sqlite3GetTempReg(pParse);
-      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
-      if( testOp!=OP_Noop ){
-        sqlite3VdbeAddOp3(v, testOp, memEndValue, addrBrk, r1);
-        sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
-      }
-      if( codeRowSetEarly ){
-        sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, r1);
-      }
-      sqlite3ReleaseTempReg(pParse, r1);
+    if( pStart==0 && pEnd==0 ){
+      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
+    }else{
+      assert( pLevel->p5==0 );
+    }
+    if( testOp!=OP_Noop ){
+      iRowidReg = iReleaseReg = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
+      sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
+      sqlite3VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
+      sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
     }
   }else if( pLevel->plan.wsFlags & (WHERE_COLUMN_RANGE|WHERE_COLUMN_EQ) ){
     /* Case 3: A scan using an index.
@@ -81937,7 +105689,7 @@ static Bitmask codeOneLoopStart(
     **         constraints but an index is selected anyway, in order
     **         to force the output order to conform to an ORDER BY.
     */  
-    int aStartOp[] = {
+    static const u8 aStartOp[] = {
       0,
       0,
       OP_Rewind,           /* 2: (!start_constraints && startEq &&  !bRev) */
@@ -81947,12 +105699,12 @@ static Bitmask codeOneLoopStart(
       OP_SeekGe,           /* 6: (start_constraints  &&  startEq && !bRev) */
       OP_SeekLe            /* 7: (start_constraints  &&  startEq &&  bRev) */
     };
-    int aEndOp[] = {
+    static const u8 aEndOp[] = {
       OP_Noop,             /* 0: (!end_constraints) */
       OP_IdxGE,            /* 1: (end_constraints && !bRev) */
       OP_IdxLT             /* 2: (end_constraints && bRev) */
     };
-    int nEq = pLevel->plan.nEq;
+    int nEq = pLevel->plan.nEq;  /* Number of == or IN terms */
     int isMinQuery = 0;          /* If this is an optimized SELECT min(x).. */
     int regBase;                 /* Base register holding constraint values */
     int r1;                      /* Temp register */
@@ -81962,14 +105714,16 @@ static Bitmask codeOneLoopStart(
     int endEq;                   /* True if range end uses ==, >= or <= */
     int start_constraints;       /* Start of range is constrained */
     int nConstraint;             /* Number of constraint terms */
-    Index *pIdx;         /* The index we will be using */
-    int iIdxCur;         /* The VDBE cursor for the index */
-    int nExtraReg = 0;   /* Number of extra registers needed */
-    int op;              /* Instruction opcode */
+    Index *pIdx;                 /* The index we will be using */
+    int iIdxCur;                 /* The VDBE cursor for the index */
+    int nExtraReg = 0;           /* Number of extra registers needed */
+    int op;                      /* Instruction opcode */
+    char *zStartAff;             /* Affinity for start of range constraint */
+    char *zEndAff;               /* Affinity for end of range constraint */
 
     pIdx = pLevel->plan.u.pIdx;
     iIdxCur = pLevel->iIdxCur;
-    k = pIdx->aiColumn[nEq];     /* Column for inequality constraints */
+    k = (nEq==pIdx->nColumn ? -1 : pIdx->aiColumn[nEq]);
 
     /* If this loop satisfies a sort order (pOrderBy) request that 
     ** was passed to this function to implement a "SELECT min(x) ..." 
@@ -82005,15 +105759,19 @@ static Bitmask codeOneLoopStart(
     ** and store the values of those terms in an array of registers
     ** starting at regBase.
     */
-    regBase = codeAllEqualityTerms(pParse, pLevel, pWC, notReady, nExtraReg);
+    regBase = codeAllEqualityTerms(
+        pParse, pLevel, pWC, notReady, nExtraReg, &zStartAff
+    );
+    zEndAff = sqlite3DbStrDup(pParse->db, zStartAff);
     addrNxt = pLevel->addrNxt;
 
-
     /* If we are doing a reverse order scan on an ascending index, or
     ** a forward order scan on a descending index, interchange the 
     ** start and end terms (pRangeStart and pRangeEnd).
     */
-    if( bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
+    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC))
+     || (bRev && pIdx->nColumn==nEq)
+    ){
       SWAP(WhereTerm *, pRangeEnd, pRangeStart);
     }
 
@@ -82028,21 +105786,31 @@ static Bitmask codeOneLoopStart(
     /* Seek the index cursor to the start of the range. */
     nConstraint = nEq;
     if( pRangeStart ){
-      int dcc = pParse->disableColCache;
-      if( pRangeEnd ){
-        pParse->disableColCache++;
+      Expr *pRight = pRangeStart->pExpr->pRight;
+      sqlite3ExprCode(pParse, pRight, regBase+nEq);
+      if( (pRangeStart->wtFlags & TERM_VNULL)==0 ){
+        sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
       }
-      sqlite3ExprCode(pParse, pRangeStart->pExpr->pRight, regBase+nEq);
-      pParse->disableColCache = dcc;
-      sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
+      if( zStartAff ){
+        if( sqlite3CompareAffinity(pRight, zStartAff[nEq])==SQLITE_AFF_NONE){
+          /* Since the comparison is to be performed with no conversions
+          ** applied to the operands, set the affinity to apply to pRight to 
+          ** SQLITE_AFF_NONE.  */
+          zStartAff[nEq] = SQLITE_AFF_NONE;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zStartAff[nEq]) ){
+          zStartAff[nEq] = SQLITE_AFF_NONE;
+        }
+      }  
       nConstraint++;
+      testcase( pRangeStart->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
     }else if( isMinQuery ){
       sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
       nConstraint++;
       startEq = 0;
       start_constraints = 1;
     }
-    codeApplyAffinity(pParse, regBase, nConstraint, pIdx);
+    codeApplyAffinity(pParse, regBase, nConstraint, zStartAff);
     op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
     assert( op!=0 );
     testcase( op==OP_Rewind );
@@ -82051,19 +105819,36 @@ static Bitmask codeOneLoopStart(
     testcase( op==OP_SeekGe );
     testcase( op==OP_SeekLe );
     testcase( op==OP_SeekLt );
-    sqlite3VdbeAddOp4(v, op, iIdxCur, addrNxt, regBase, 
-                      SQLITE_INT_TO_PTR(nConstraint), P4_INT32);
+    sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
 
     /* Load the value for the inequality constraint at the end of the
     ** range (if any).
     */
     nConstraint = nEq;
     if( pRangeEnd ){
-      sqlite3ExprCode(pParse, pRangeEnd->pExpr->pRight, regBase+nEq);
-      sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
-      codeApplyAffinity(pParse, regBase, nEq+1, pIdx);
+      Expr *pRight = pRangeEnd->pExpr->pRight;
+      sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
+      sqlite3ExprCode(pParse, pRight, regBase+nEq);
+      if( (pRangeEnd->wtFlags & TERM_VNULL)==0 ){
+        sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
+      }
+      if( zEndAff ){
+        if( sqlite3CompareAffinity(pRight, zEndAff[nEq])==SQLITE_AFF_NONE){
+          /* Since the comparison is to be performed with no conversions
+          ** applied to the operands, set the affinity to apply to pRight to 
+          ** SQLITE_AFF_NONE.  */
+          zEndAff[nEq] = SQLITE_AFF_NONE;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zEndAff[nEq]) ){
+          zEndAff[nEq] = SQLITE_AFF_NONE;
+        }
+      }  
+      codeApplyAffinity(pParse, regBase, nEq+1, zEndAff);
       nConstraint++;
+      testcase( pRangeEnd->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
     }
+    sqlite3DbFree(pParse->db, zStartAff);
+    sqlite3DbFree(pParse->db, zEndAff);
 
     /* Top of the loop body */
     pLevel->p2 = sqlite3VdbeCurrentAddr(v);
@@ -82074,8 +105859,7 @@ static Bitmask codeOneLoopStart(
     testcase( op==OP_IdxGE );
     testcase( op==OP_IdxLT );
     if( op!=OP_Noop ){
-      sqlite3VdbeAddOp4(v, op, iIdxCur, addrNxt, regBase,
-                        SQLITE_INT_TO_PTR(nConstraint), P4_INT32);
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
       sqlite3VdbeChangeP5(v, endEq!=bRev ?1:0);
     }
 
@@ -82086,29 +105870,32 @@ static Bitmask codeOneLoopStart(
     r1 = sqlite3GetTempReg(pParse);
     testcase( pLevel->plan.wsFlags & WHERE_BTM_LIMIT );
     testcase( pLevel->plan.wsFlags & WHERE_TOP_LIMIT );
-    if( pLevel->plan.wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT) ){
+    if( (pLevel->plan.wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 ){
       sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, nEq, r1);
       sqlite3VdbeAddOp2(v, OP_IsNull, r1, addrCont);
     }
+    sqlite3ReleaseTempReg(pParse, r1);
 
     /* Seek the table cursor, if required */
     disableTerm(pLevel, pRangeStart);
     disableTerm(pLevel, pRangeEnd);
-    codeRowSetEarly = regRowSet>=0 ? whereRowReadyForOutput(pWC) : 0;
-    if( !omitTable || codeRowSetEarly ){
-      sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, r1);
-      if( codeRowSetEarly ){
-        sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, r1);
-      }else{
-        sqlite3VdbeAddOp2(v, OP_Seek, iCur, r1);  /* Deferred seek */
-      }
+    if( !omitTable ){
+      iRowidReg = iReleaseReg = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, iRowidReg);
+      sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
+      sqlite3VdbeAddOp2(v, OP_Seek, iCur, iRowidReg);  /* Deferred seek */
     }
-    sqlite3ReleaseTempReg(pParse, r1);
 
     /* Record the instruction used to terminate the loop. Disable 
     ** WHERE clause terms made redundant by the index range scan.
     */
-    pLevel->op = bRev ? OP_Prev : OP_Next;
+    if( pLevel->plan.wsFlags & WHERE_UNIQUE ){
+      pLevel->op = OP_Noop;
+    }else if( bRev ){
+      pLevel->op = OP_Prev;
+    }else{
+      pLevel->op = OP_Next;
+    }
     pLevel->p1 = iIdxCur;
   }else
 
@@ -82126,67 +105913,196 @@ static Bitmask codeOneLoopStart(
     **   SELECT * FROM t1 WHERE a=5 OR b=7 OR (c=11 AND d=13)
     **
     ** In the example, there are three indexed terms connected by OR.
-    ** The top of the loop is constructed by creating a RowSet object
-    ** and populating it.  Then looping over elements of the rowset.
+    ** The top of the loop looks like this:
     **
-    **        Null 1
-    **        # fill RowSet 1 with entries where a=5 using i1
-    **        # fill Rowset 1 with entries where b=7 using i2
-    **        # fill Rowset 1 with entries where c=11 and d=13 i3 and t1
-    **     A: RowSetRead 1, B, 2
-    **        Seek       i, 2
+    **          Null       1                # Zero the rowset in reg 1
     **
-    ** The bottom of the loop looks like this:
+    ** Then, for each indexed term, the following. The arguments to
+    ** RowSetTest are such that the rowid of the current row is inserted
+    ** into the RowSet. If it is already present, control skips the
+    ** Gosub opcode and jumps straight to the code generated by WhereEnd().
+    **
+    **        sqlite3WhereBegin(<term>)
+    **          RowSetTest                  # Insert rowid into rowset
+    **          Gosub      2 A
+    **        sqlite3WhereEnd()
+    **
+    ** Following the above, code to terminate the loop. Label A, the target
+    ** of the Gosub above, jumps to the instruction right after the Goto.
+    **
+    **          Null       1                # Zero the rowset in reg 1
+    **          Goto       B                # The loop is finished.
+    **
+    **       A: <loop body>                 # Return data, whatever.
+    **
+    **          Return     2                # Jump back to the Gosub
+    **
+    **       B: <after the loop>
     **
-    **        Goto       0, A
-    **     B:
     */
-    int regOrRowset;       /* Register holding the RowSet object */
-    int regNextRowid;      /* Register holding next rowid */
     WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
-    WhereTerm *pOrTerm;    /* A single subterm within the OR-clause */
-    SrcList oneTab;        /* Shortened table list */
+    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */
+    Index *pCov = 0;             /* Potential covering index (or NULL) */
+    int iCovCur = pParse->nTab++;  /* Cursor used for index scans (if any) */
+
+    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
+    int regRowset = 0;                        /* Register for RowSet object */
+    int regRowid = 0;                         /* Register holding rowid */
+    int iLoopBody = sqlite3VdbeMakeLabel(v);  /* Start of loop body */
+    int iRetInit;                             /* Address of regReturn init */
+    int untestedTerms = 0;             /* Some terms not completely tested */
+    int ii;                            /* Loop counter */
+    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
    
     pTerm = pLevel->plan.u.pTerm;
     assert( pTerm!=0 );
     assert( pTerm->eOperator==WO_OR );
     assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
     pOrWc = &pTerm->u.pOrInfo->wc;
-    codeRowSetEarly = (regRowSet>=0 && pWC->nTerm==1) ?1:0;
+    pLevel->op = OP_Return;
+    pLevel->p1 = regReturn;
 
-    if( codeRowSetEarly ){
-      regOrRowset = regRowSet;
+    /* Set up a new SrcList in pOrTab containing the table being scanned
+    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
+    ** This becomes the SrcList in the recursive call to sqlite3WhereBegin().
+    */
+    if( pWInfo->nLevel>1 ){
+      int nNotReady;                 /* The number of notReady tables */
+      struct SrcList_item *origSrc;     /* Original list of tables */
+      nNotReady = pWInfo->nLevel - iLevel - 1;
+      pOrTab = sqlite3StackAllocRaw(pParse->db,
+                            sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0]));
+      if( pOrTab==0 ) return notReady;
+      pOrTab->nAlloc = (i16)(nNotReady + 1);
+      pOrTab->nSrc = pOrTab->nAlloc;
+      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
+      origSrc = pWInfo->pTabList->a;
+      for(k=1; k<=nNotReady; k++){
+        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
+      }
     }else{
-      regOrRowset = sqlite3GetTempReg(pParse);
-      sqlite3VdbeAddOp2(v, OP_Null, 0, regOrRowset);
+      pOrTab = pWInfo->pTabList;
     }
-    oneTab.nSrc = 1;
-    oneTab.nAlloc = 1;
-    oneTab.a[0] = *pTabItem;
-    for(j=0, pOrTerm=pOrWc->a; j<pOrWc->nTerm; j++, pOrTerm++){
-      WhereInfo *pSubWInfo;
-      if( pOrTerm->leftCursor!=iCur && pOrTerm->eOperator!=WO_AND ) continue;
-      pSubWInfo = sqlite3WhereBegin(pParse, &oneTab, pOrTerm->pExpr, 0,
-                        WHERE_FILL_ROWSET | WHERE_OMIT_OPEN | WHERE_OMIT_CLOSE,
-                        regOrRowset);
-      if( pSubWInfo ){
-        sqlite3WhereEnd(pSubWInfo);
+
+    /* Initialize the rowset register to contain NULL. An SQL NULL is 
+    ** equivalent to an empty rowset.
+    **
+    ** Also initialize regReturn to contain the address of the instruction 
+    ** immediately following the OP_Return at the bottom of the loop. This
+    ** is required in a few obscure LEFT JOIN cases where control jumps
+    ** over the top of the loop into the body of it. In this case the 
+    ** correct response for the end-of-loop code (the OP_Return) is to 
+    ** fall through to the next instruction, just as an OP_Next does if
+    ** called on an uninitialized cursor.
+    */
+    if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
+      regRowset = ++pParse->nMem;
+      regRowid = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
+    }
+    iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn);
+
+    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
+    ** Then for every term xN, evaluate as the subexpression: xN AND z
+    ** That way, terms in y that are factored into the disjunction will
+    ** be picked up by the recursive calls to sqlite3WhereBegin() below.
+    **
+    ** Actually, each subexpression is converted to "xN AND w" where w is
+    ** the "interesting" terms of z - terms that did not originate in the
+    ** ON or USING clause of a LEFT JOIN, and terms that are usable as 
+    ** indices.
+    */
+    if( pWC->nTerm>1 ){
+      int iTerm;
+      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
+        Expr *pExpr = pWC->a[iTerm].pExpr;
+        if( ExprHasProperty(pExpr, EP_FromJoin) ) continue;
+        if( pWC->a[iTerm].wtFlags & (TERM_VIRTUAL|TERM_ORINFO) ) continue;
+        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
+        pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
+        pAndExpr = sqlite3ExprAnd(pParse->db, pAndExpr, pExpr);
+      }
+      if( pAndExpr ){
+        pAndExpr = sqlite3PExpr(pParse, TK_AND, 0, pAndExpr, 0);
       }
     }
-    sqlite3VdbeResolveLabel(v, addrCont);
-    if( !codeRowSetEarly ){
-      regNextRowid = sqlite3GetTempReg(pParse);
-      addrCont = 
-         sqlite3VdbeAddOp3(v, OP_RowSetRead, regOrRowset,addrBrk,regNextRowid);
-      sqlite3VdbeAddOp2(v, OP_Seek, iCur, regNextRowid);
-      sqlite3ReleaseTempReg(pParse, regNextRowid);
-      /* sqlite3ReleaseTempReg(pParse, regOrRowset); // Preserve the RowSet */
-      pLevel->op = OP_Goto;
-      pLevel->p2 = addrCont;
-    }else{
-      pLevel->op = OP_Noop;
+
+    for(ii=0; ii<pOrWc->nTerm; ii++){
+      WhereTerm *pOrTerm = &pOrWc->a[ii];
+      if( pOrTerm->leftCursor==iCur || pOrTerm->eOperator==WO_AND ){
+        WhereInfo *pSubWInfo;          /* Info for single OR-term scan */
+        Expr *pOrExpr = pOrTerm->pExpr;
+        if( pAndExpr ){
+          pAndExpr->pLeft = pOrExpr;
+          pOrExpr = pAndExpr;
+        }
+        /* Loop through table entries that match term pOrTerm. */
+        pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
+                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
+                        WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur);
+        assert( pSubWInfo || pParse->nErr || pParse->db->mallocFailed );
+        if( pSubWInfo ){
+          WhereLevel *pLvl;
+          explainOneScan(
+              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
+          );
+          if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
+            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
+            int r;
+            r = sqlite3ExprCodeGetColumn(pParse, pTabItem->pTab, -1, iCur, 
+                                         regRowid, 0);
+            sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset,
+                                 sqlite3VdbeCurrentAddr(v)+2, r, iSet);
+          }
+          sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);
+
+          /* The pSubWInfo->untestedTerms flag means that this OR term
+          ** contained one or more AND term from a notReady table.  The
+          ** terms from the notReady table could not be tested and will
+          ** need to be tested later.
+          */
+          if( pSubWInfo->untestedTerms ) untestedTerms = 1;
+
+          /* If all of the OR-connected terms are optimized using the same
+          ** index, and the index is opened using the same cursor number
+          ** by each call to sqlite3WhereBegin() made by this loop, it may
+          ** be possible to use that index as a covering index.
+          **
+          ** If the call to sqlite3WhereBegin() above resulted in a scan that
+          ** uses an index, and this is either the first OR-connected term
+          ** processed or the index is the same as that used by all previous
+          ** terms, set pCov to the candidate covering index. Otherwise, set 
+          ** pCov to NULL to indicate that no candidate covering index will 
+          ** be available.
+          */
+          pLvl = &pSubWInfo->a[0];
+          if( (pLvl->plan.wsFlags & WHERE_INDEXED)!=0
+           && (pLvl->plan.wsFlags & WHERE_TEMP_INDEX)==0
+           && (ii==0 || pLvl->plan.u.pIdx==pCov)
+          ){
+            assert( pLvl->iIdxCur==iCovCur );
+            pCov = pLvl->plan.u.pIdx;
+          }else{
+            pCov = 0;
+          }
+
+          /* Finish the loop through table entries that match term pOrTerm. */
+          sqlite3WhereEnd(pSubWInfo);
+        }
+      }
     }
-    disableTerm(pLevel, pTerm);
+    pLevel->u.pCovidx = pCov;
+    if( pCov ) pLevel->iIdxCur = iCovCur;
+    if( pAndExpr ){
+      pAndExpr->pLeft = 0;
+      sqlite3ExprDelete(pParse->db, pAndExpr);
+    }
+    sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
+    sqlite3VdbeResolveLabel(v, iLoopBody);
+
+    if( pWInfo->nLevel>1 ) sqlite3StackFree(pParse->db, pOrTab);
+    if( !untestedTerms ) disableTerm(pLevel, pTerm);
   }else
 #endif /* SQLITE_OMIT_OR_OPTIMIZATION */
 
@@ -82194,35 +106110,41 @@ static Bitmask codeOneLoopStart(
     /* Case 5:  There is no usable index.  We must do a complete
     **          scan of the entire table.
     */
+    static const u8 aStep[] = { OP_Next, OP_Prev };
+    static const u8 aStart[] = { OP_Rewind, OP_Last };
+    assert( bRev==0 || bRev==1 );
     assert( omitTable==0 );
-    assert( bRev==0 );
-    pLevel->op = OP_Next;
+    pLevel->op = aStep[bRev];
     pLevel->p1 = iCur;
-    pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, OP_Rewind, iCur, addrBrk);
+    pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
     pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
-    codeRowSetEarly = 0;
   }
   notReady &= ~getMask(pWC->pMaskSet, iCur);
 
   /* Insert code to test every subexpression that can be completely
   ** computed using the current set of tables.
+  **
+  ** IMPLEMENTATION-OF: R-49525-50935 Terms that cannot be satisfied through
+  ** the use of indices become tests that are evaluated against each row of
+  ** the relevant input tables.
   */
-  k = 0;
   for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
     Expr *pE;
-    testcase( pTerm->wtFlags & TERM_VIRTUAL );
+    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
     testcase( pTerm->wtFlags & TERM_CODED );
     if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
-    if( (pTerm->prereqAll & notReady)!=0 ) continue;
+    if( (pTerm->prereqAll & notReady)!=0 ){
+      testcase( pWInfo->untestedTerms==0
+               && (pWInfo->wctrlFlags & WHERE_ONETABLE_ONLY)!=0 );
+      pWInfo->untestedTerms = 1;
+      continue;
+    }
     pE = pTerm->pExpr;
     assert( pE!=0 );
     if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
       continue;
     }
-    pParse->disableColCache += k;
     sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL);
-    pParse->disableColCache -= k;
-    k = 1;
     pTerm->wtFlags |= TERM_CODED;
   }
 
@@ -82233,36 +106155,21 @@ static Bitmask codeOneLoopStart(
     pLevel->addrFirst = sqlite3VdbeCurrentAddr(v);
     sqlite3VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
     VdbeComment((v, "record LEFT JOIN hit"));
-    sqlite3ExprClearColumnCache(pParse, pLevel->iTabCur);
-    sqlite3ExprClearColumnCache(pParse, pLevel->iIdxCur);
+    sqlite3ExprCacheClear(pParse);
     for(pTerm=pWC->a, j=0; j<pWC->nTerm; j++, pTerm++){
-      testcase( pTerm->wtFlags & TERM_VIRTUAL );
+      testcase( pTerm->wtFlags & TERM_VIRTUAL );  /* IMP: R-30575-11662 */
       testcase( pTerm->wtFlags & TERM_CODED );
       if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
-      if( (pTerm->prereqAll & notReady)!=0 ) continue;
+      if( (pTerm->prereqAll & notReady)!=0 ){
+        assert( pWInfo->untestedTerms );
+        continue;
+      }
       assert( pTerm->pExpr );
       sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
       pTerm->wtFlags |= TERM_CODED;
     }
   }
-
-  /*
-  ** If it was requested to store the results in a rowset and that has
-  ** not already been do, then do so now.
-  */
-  if( regRowSet>=0 && !codeRowSetEarly ){
-    int r1 = sqlite3GetTempReg(pParse);
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-    if(  (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
-      sqlite3VdbeAddOp2(v, OP_VRowid, iCur, r1);
-    }else
-#endif
-    {
-      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
-    }
-    sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, r1);
-    sqlite3ReleaseTempReg(pParse, r1);
-  }
+  sqlite3ReleaseTempReg(pParse, iReleaseReg);
 
   return notReady;
 }
@@ -82284,17 +106191,24 @@ static int nQPlan = 0;              /* Next free slow in _query_plan[] */
 ** Free a WhereInfo structure
 */
 static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
-  if( pWInfo ){
+  if( ALWAYS(pWInfo) ){
     int i;
     for(i=0; i<pWInfo->nLevel; i++){
       sqlite3_index_info *pInfo = pWInfo->a[i].pIdxInfo;
       if( pInfo ){
-        assert( pInfo->needToFreeIdxStr==0 || db->mallocFailed );
+        /* assert( pInfo->needToFreeIdxStr==0 || db->mallocFailed ); */
         if( pInfo->needToFreeIdxStr ){
           sqlite3_free(pInfo->idxStr);
-	}
+        }
         sqlite3DbFree(db, pInfo);
       }
+      if( pWInfo->a[i].plan.wsFlags & WHERE_TEMP_INDEX ){
+        Index *pIdx = pWInfo->a[i].plan.u.pIdx;
+        if( pIdx ){
+          sqlite3DbFree(db, pIdx->zColAff);
+          sqlite3DbFree(db, pIdx);
+        }
+      }
     }
     whereClauseClear(pWInfo->pWC);
     sqlite3DbFree(db, pWInfo);
@@ -82395,10 +106309,13 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
   SrcList *pTabList,    /* A list of all tables to be scanned */
   Expr *pWhere,         /* The WHERE clause */
   ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
-  u8 wctrlFlags,        /* One of the WHERE_* flags defined in sqliteInt.h */
-  int regRowSet         /* Register hold RowSet if WHERE_FILL_ROWSET is set */
+  ExprList *pDistinct,  /* The select-list for DISTINCT queries - or NULL */
+  u16 wctrlFlags,       /* One of the WHERE_* flags defined in sqliteInt.h */
+  int iIdxCur           /* If WHERE_ONETABLE_ONLY is set, index cursor number */
 ){
   int i;                     /* Loop counter */
+  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
+  int nTabList;              /* Number of elements in pTabList */
   WhereInfo *pWInfo;         /* Will become the return value of this function */
   Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
   Bitmask notReady;          /* Cursors that are not yet positioned */
@@ -82409,54 +106326,67 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
   int iFrom;                      /* First unused FROM clause element */
   int andFlags;              /* AND-ed combination of all pWC->a[].wtFlags */
   sqlite3 *db;               /* Database connection */
-  ExprList *pOrderBy = 0;
 
   /* The number of tables in the FROM clause is limited by the number of
   ** bits in a Bitmask 
   */
+  testcase( pTabList->nSrc==BMS );
   if( pTabList->nSrc>BMS ){
     sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);
     return 0;
   }
 
-  if( ppOrderBy ){
-    pOrderBy = *ppOrderBy;
-  }
+  /* This function normally generates a nested loop for all tables in 
+  ** pTabList.  But if the WHERE_ONETABLE_ONLY flag is set, then we should
+  ** only generate code for the first table in pTabList and assume that
+  ** any cursors associated with subsequent tables are uninitialized.
+  */
+  nTabList = (wctrlFlags & WHERE_ONETABLE_ONLY) ? 1 : pTabList->nSrc;
 
   /* Allocate and initialize the WhereInfo structure that will become the
-  ** return value.
+  ** return value. A single allocation is used to store the WhereInfo
+  ** struct, the contents of WhereInfo.a[], the WhereClause structure
+  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
+  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
+  ** some architectures. Hence the ROUND8() below.
   */
   db = pParse->db;
-  pWInfo = sqlite3DbMallocZero(db,  
-                      sizeof(WhereInfo)
-                      + (pTabList->nSrc-1)*sizeof(WhereLevel)
-                      + sizeof(WhereClause)
-                      + sizeof(WhereMaskSet)
-           );
+  nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel));
+  pWInfo = sqlite3DbMallocZero(db, 
+      nByteWInfo + 
+      sizeof(WhereClause) +
+      sizeof(WhereMaskSet)
+  );
   if( db->mallocFailed ){
+    sqlite3DbFree(db, pWInfo);
+    pWInfo = 0;
     goto whereBeginError;
   }
-  pWInfo->nLevel = pTabList->nSrc;
+  pWInfo->nLevel = nTabList;
   pWInfo->pParse = pParse;
   pWInfo->pTabList = pTabList;
   pWInfo->iBreak = sqlite3VdbeMakeLabel(v);
-  pWInfo->regRowSet = (wctrlFlags & WHERE_FILL_ROWSET) ? regRowSet : -1;
-  pWInfo->pWC = pWC = (WhereClause*)&pWInfo->a[pWInfo->nLevel];
+  pWInfo->pWC = pWC = (WhereClause *)&((u8 *)pWInfo)[nByteWInfo];
   pWInfo->wctrlFlags = wctrlFlags;
+  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
   pMaskSet = (WhereMaskSet*)&pWC[1];
 
+  /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
+  ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
+  if( db->flags & SQLITE_DistinctOpt ) pDistinct = 0;
+
   /* Split the WHERE clause into separate subexpressions where each
   ** subexpression is separated by an AND operator.
   */
   initMaskSet(pMaskSet);
-  whereClauseInit(pWC, pParse, pMaskSet);
+  whereClauseInit(pWC, pParse, pMaskSet, wctrlFlags);
   sqlite3ExprCodeConstants(pParse, pWhere);
-  whereSplit(pWC, pWhere, TK_AND);
+  whereSplit(pWC, pWhere, TK_AND);   /* IMP: R-15842-53296 */
     
   /* Special case: a WHERE clause that is constant.  Evaluate the
   ** expression and either jump over all of the code or fall thru.
   */
-  if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstantNotJoin(pWhere)) ){
+  if( pWhere && (nTabList==0 || sqlite3ExprIsConstantNotJoin(pWhere)) ){
     sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE_JUMPIFNULL);
     pWhere = 0;
   }
@@ -82471,9 +106401,25 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
   ** of the join.  Subtracting one from the right table bitmask gives a
   ** bitmask for all tables to the left of the join.  Knowing the bitmask
   ** for all tables to the left of a left join is important.  Ticket #3015.
+  **
+  ** Configure the WhereClause.vmask variable so that bits that correspond
+  ** to virtual table cursors are set. This is used to selectively disable 
+  ** the OR-to-IN transformation in exprAnalyzeOrTerm(). It is not helpful 
+  ** with virtual tables.
+  **
+  ** Note that bitmasks are created for all pTabList->nSrc tables in
+  ** pTabList, not just the first nTabList tables.  nTabList is normally
+  ** equal to pTabList->nSrc but might be shortened to 1 if the
+  ** WHERE_ONETABLE_ONLY flag is set.
   */
+  assert( pWC->vmask==0 && pMaskSet->n==0 );
   for(i=0; i<pTabList->nSrc; i++){
     createMask(pMaskSet, pTabList->a[i].iCursor);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( ALWAYS(pTabList->a[i].pTab) && IsVirtual(pTabList->a[i].pTab) ){
+      pWC->vmask |= ((Bitmask)1 << i);
+    }
+#endif
   }
 #ifndef NDEBUG
   {
@@ -82496,6 +106442,15 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
     goto whereBeginError;
   }
 
+  /* Check if the DISTINCT qualifier, if there is one, is redundant. 
+  ** If it is, then set pDistinct to NULL and WhereInfo.eDistinct to
+  ** WHERE_DISTINCT_UNIQUE to tell the caller to ignore the DISTINCT.
+  */
+  if( pDistinct && isDistinctRedundant(pParse, pTabList, pWC, pDistinct) ){
+    pDistinct = 0;
+    pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+  }
+
   /* Chose the best index to use for each table in the FROM clause.
   **
   ** This loop fills in the following fields:
@@ -82512,81 +106467,185 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
   ** clause.
   */
   notReady = ~(Bitmask)0;
-  pTabItem = pTabList->a;
-  pLevel = pWInfo->a;
   andFlags = ~0;
   WHERETRACE(("*** Optimizer Start ***\n"));
-  for(i=iFrom=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
+  for(i=iFrom=0, pLevel=pWInfo->a; i<nTabList; i++, pLevel++){
     WhereCost bestPlan;         /* Most efficient plan seen so far */
     Index *pIdx;                /* Index for FROM table at pTabItem */
     int j;                      /* For looping over FROM tables */
-    int bestJ = 0;              /* The value of j */
+    int bestJ = -1;             /* The value of j */
     Bitmask m;                  /* Bitmask value for j or bestJ */
-    int once = 0;               /* True when first table is seen */
+    int isOptimal;              /* Iterator for optimal/non-optimal search */
+    int nUnconstrained;         /* Number tables without INDEXED BY */
+    Bitmask notIndexed;         /* Mask of tables that cannot use an index */
 
     memset(&bestPlan, 0, sizeof(bestPlan));
     bestPlan.rCost = SQLITE_BIG_DBL;
-    for(j=iFrom, pTabItem=&pTabList->a[j]; j<pTabList->nSrc; j++, pTabItem++){
-      int doNotReorder;  /* True if this table should not be reordered */
-      WhereCost sCost;   /* Cost information from bestIndex() */
+    WHERETRACE(("*** Begin search for loop %d ***\n", i));
 
-      doNotReorder =  (pTabItem->jointype & (JT_LEFT|JT_CROSS))!=0;
-      if( once && doNotReorder ) break;
-      m = getMask(pMaskSet, pTabItem->iCursor);
-      if( (m & notReady)==0 ){
-        if( j==iFrom ) iFrom++;
-        continue;
-      }
-      assert( pTabItem->pTab );
+    /* Loop through the remaining entries in the FROM clause to find the
+    ** next nested loop. The loop tests all FROM clause entries
+    ** either once or twice. 
+    **
+    ** The first test is always performed if there are two or more entries
+    ** remaining and never performed if there is only one FROM clause entry
+    ** to choose from.  The first test looks for an "optimal" scan.  In
+    ** this context an optimal scan is one that uses the same strategy
+    ** for the given FROM clause entry as would be selected if the entry
+    ** were used as the innermost nested loop.  In other words, a table
+    ** is chosen such that the cost of running that table cannot be reduced
+    ** by waiting for other tables to run first.  This "optimal" test works
+    ** by first assuming that the FROM clause is on the inner loop and finding
+    ** its query plan, then checking to see if that query plan uses any
+    ** other FROM clause terms that are notReady.  If no notReady terms are
+    ** used then the "optimal" query plan works.
+    **
+    ** Note that the WhereCost.nRow parameter for an optimal scan might
+    ** not be as small as it would be if the table really were the innermost
+    ** join.  The nRow value can be reduced by WHERE clause constraints
+    ** that do not use indices.  But this nRow reduction only happens if the
+    ** table really is the innermost join.  
+    **
+    ** The second loop iteration is only performed if no optimal scan
+    ** strategies were found by the first iteration. This second iteration
+    ** is used to search for the lowest cost scan overall.
+    **
+    ** Previous versions of SQLite performed only the second iteration -
+    ** the next outermost loop was always that with the lowest overall
+    ** cost. However, this meant that SQLite could select the wrong plan
+    ** for scripts such as the following:
+    **   
+    **   CREATE TABLE t1(a, b); 
+    **   CREATE TABLE t2(c, d);
+    **   SELECT * FROM t2, t1 WHERE t2.rowid = t1.a;
+    **
+    ** The best strategy is to iterate through table t1 first. However it
+    ** is not possible to determine this with a simple greedy algorithm.
+    ** Since the cost of a linear scan through table t2 is the same 
+    ** as the cost of a linear scan through table t1, a simple greedy 
+    ** algorithm may choose to use t2 for the outer loop, which is a much
+    ** costlier approach.
+    */
+    nUnconstrained = 0;
+    notIndexed = 0;
+    for(isOptimal=(iFrom<nTabList-1); isOptimal>=0 && bestJ<0; isOptimal--){
+      Bitmask mask;             /* Mask of tables not yet ready */
+      for(j=iFrom, pTabItem=&pTabList->a[j]; j<nTabList; j++, pTabItem++){
+        int doNotReorder;    /* True if this table should not be reordered */
+        WhereCost sCost;     /* Cost information from best[Virtual]Index() */
+        ExprList *pOrderBy;  /* ORDER BY clause for index to optimize */
+        ExprList *pDist;     /* DISTINCT clause for index to optimize */
+  
+        doNotReorder =  (pTabItem->jointype & (JT_LEFT|JT_CROSS))!=0;
+        if( j!=iFrom && doNotReorder ) break;
+        m = getMask(pMaskSet, pTabItem->iCursor);
+        if( (m & notReady)==0 ){
+          if( j==iFrom ) iFrom++;
+          continue;
+        }
+        mask = (isOptimal ? m : notReady);
+        pOrderBy = ((i==0 && ppOrderBy )?*ppOrderBy:0);
+        pDist = (i==0 ? pDistinct : 0);
+        if( pTabItem->pIndex==0 ) nUnconstrained++;
+  
+        WHERETRACE(("=== trying table %d with isOptimal=%d ===\n",
+                    j, isOptimal));
+        assert( pTabItem->pTab );
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-      if( IsVirtual(pTabItem->pTab) ){
-        sqlite3_index_info *pVtabIdx; /* Current virtual index */
-        sqlite3_index_info **ppIdxInfo = &pWInfo->a[j].pIdxInfo;
-        sCost.rCost = bestVirtualIndex(pParse, pWC, pTabItem, notReady,
-                                       ppOrderBy ? *ppOrderBy : 0, i==0,
-                                       ppIdxInfo);
-        sCost.plan.wsFlags = WHERE_VIRTUALTABLE;
-        sCost.plan.u.pVtabIdx = pVtabIdx = *ppIdxInfo;
-        if( pVtabIdx && pVtabIdx->orderByConsumed ){
-          sCost.plan.wsFlags = WHERE_VIRTUALTABLE | WHERE_ORDERBY;
-        }
-        sCost.plan.nEq = 0;
-        if( (SQLITE_BIG_DBL/2.0)<sCost.rCost ){
-          /* The cost is not allowed to be larger than SQLITE_BIG_DBL (the
-          ** inital value of lowestCost in this loop. If it is, then
-          ** the (cost<lowestCost) test below will never be true.
-          */ 
-          sCost.rCost = (SQLITE_BIG_DBL/2.0);
-        }
-      }else 
+        if( IsVirtual(pTabItem->pTab) ){
+          sqlite3_index_info **pp = &pWInfo->a[j].pIdxInfo;
+          bestVirtualIndex(pParse, pWC, pTabItem, mask, notReady, pOrderBy,
+                           &sCost, pp);
+        }else 
 #endif
-      {
-        bestIndex(pParse, pWC, pTabItem, notReady,
-                  (i==0 && ppOrderBy) ? *ppOrderBy : 0, &sCost);
+        {
+          bestBtreeIndex(pParse, pWC, pTabItem, mask, notReady, pOrderBy,
+              pDist, &sCost);
+        }
+        assert( isOptimal || (sCost.used&notReady)==0 );
+
+        /* If an INDEXED BY clause is present, then the plan must use that
+        ** index if it uses any index at all */
+        assert( pTabItem->pIndex==0 
+                  || (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0
+                  || sCost.plan.u.pIdx==pTabItem->pIndex );
+
+        if( isOptimal && (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0 ){
+          notIndexed |= m;
+        }
+
+        /* Conditions under which this table becomes the best so far:
+        **
+        **   (1) The table must not depend on other tables that have not
+        **       yet run.
+        **
+        **   (2) A full-table-scan plan cannot supercede indexed plan unless
+        **       the full-table-scan is an "optimal" plan as defined above.
+        **
+        **   (3) All tables have an INDEXED BY clause or this table lacks an
+        **       INDEXED BY clause or this table uses the specific
+        **       index specified by its INDEXED BY clause.  This rule ensures
+        **       that a best-so-far is always selected even if an impossible
+        **       combination of INDEXED BY clauses are given.  The error
+        **       will be detected and relayed back to the application later.
+        **       The NEVER() comes about because rule (2) above prevents
+        **       An indexable full-table-scan from reaching rule (3).
+        **
+        **   (4) The plan cost must be lower than prior plans or else the
+        **       cost must be the same and the number of rows must be lower.
+        */
+        if( (sCost.used&notReady)==0                       /* (1) */
+            && (bestJ<0 || (notIndexed&m)!=0               /* (2) */
+                || (bestPlan.plan.wsFlags & WHERE_NOT_FULLSCAN)==0
+                || (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0)
+            && (nUnconstrained==0 || pTabItem->pIndex==0   /* (3) */
+                || NEVER((sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0))
+            && (bestJ<0 || sCost.rCost<bestPlan.rCost      /* (4) */
+                || (sCost.rCost<=bestPlan.rCost 
+                 && sCost.plan.nRow<bestPlan.plan.nRow))
+        ){
+          WHERETRACE(("=== table %d is best so far"
+                      " with cost=%g and nRow=%g\n",
+                      j, sCost.rCost, sCost.plan.nRow));
+          bestPlan = sCost;
+          bestJ = j;
+        }
+        if( doNotReorder ) break;
       }
-      if( once==0 || sCost.rCost<bestPlan.rCost ){
-        once = 1;
-        bestPlan = sCost;
-        bestJ = j;
-      }
-      if( doNotReorder ) break;
     }
-    assert( once );
+    assert( bestJ>=0 );
     assert( notReady & getMask(pMaskSet, pTabList->a[bestJ].iCursor) );
-    WHERETRACE(("*** Optimizer selects table %d for loop %d\n", bestJ,
-           pLevel-pWInfo->a));
-    if( (bestPlan.plan.wsFlags & WHERE_ORDERBY)!=0 ){
+    WHERETRACE(("*** Optimizer selects table %d for loop %d"
+                " with cost=%g and nRow=%g\n",
+                bestJ, pLevel-pWInfo->a, bestPlan.rCost, bestPlan.plan.nRow));
+    /* The ALWAYS() that follows was added to hush up clang scan-build */
+    if( (bestPlan.plan.wsFlags & WHERE_ORDERBY)!=0 && ALWAYS(ppOrderBy) ){
       *ppOrderBy = 0;
     }
+    if( (bestPlan.plan.wsFlags & WHERE_DISTINCT)!=0 ){
+      assert( pWInfo->eDistinct==0 );
+      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+    }
     andFlags &= bestPlan.plan.wsFlags;
     pLevel->plan = bestPlan.plan;
-    if( bestPlan.plan.wsFlags & WHERE_INDEXED ){
-      pLevel->iIdxCur = pParse->nTab++;
+    testcase( bestPlan.plan.wsFlags & WHERE_INDEXED );
+    testcase( bestPlan.plan.wsFlags & WHERE_TEMP_INDEX );
+    if( bestPlan.plan.wsFlags & (WHERE_INDEXED|WHERE_TEMP_INDEX) ){
+      if( (wctrlFlags & WHERE_ONETABLE_ONLY) 
+       && (bestPlan.plan.wsFlags & WHERE_TEMP_INDEX)==0 
+      ){
+        pLevel->iIdxCur = iIdxCur;
+      }else{
+        pLevel->iIdxCur = pParse->nTab++;
+      }
     }else{
       pLevel->iIdxCur = -1;
     }
     notReady &= ~getMask(pMaskSet, pTabList->a[bestJ].iCursor);
-    pLevel->iFrom = bestJ;
+    pLevel->iFrom = (u8)bestJ;
+    if( bestPlan.plan.nRow>=(double)1 ){
+      pParse->nQueryLoop *= bestPlan.plan.nRow;
+    }
 
     /* Check that if the table scanned by this loop iteration had an
     ** INDEXED BY clause attached to it, that the named index is being
@@ -82607,7 +106666,7 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
     }
   }
   WHERETRACE(("*** Optimizer Finished ***\n"));
-  if( db->mallocFailed ){
+  if( pParse->nErr || db->mallocFailed ){
     goto whereBeginError;
   }
 
@@ -82633,88 +106692,75 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
   ** searching those tables.
   */
   sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
-  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
+  notReady = ~(Bitmask)0;
+  pWInfo->nRowOut = (double)1;
+  for(i=0, pLevel=pWInfo->a; i<nTabList; i++, pLevel++){
     Table *pTab;     /* Table to open */
     int iDb;         /* Index of database containing table/index */
 
-#ifndef SQLITE_OMIT_EXPLAIN
-    if( pParse->explain==2 ){
-      char *zMsg;
-      struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom];
-      zMsg = sqlite3MPrintf(db, "TABLE %s", pItem->zName);
-      if( pItem->zAlias ){
-        zMsg = sqlite3MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
-      }
-      if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
-        zMsg = sqlite3MAppendf(db, zMsg, "%s WITH INDEX %s",
-           zMsg, pLevel->plan.u.pIdx->zName);
-      }else if( pLevel->plan.wsFlags & WHERE_MULTI_OR ){
-        zMsg = sqlite3MAppendf(db, zMsg, "%s VIA MULTI-INDEX UNION", zMsg);
-      }else if( pLevel->plan.wsFlags & (WHERE_ROWID_EQ|WHERE_ROWID_RANGE) ){
-        zMsg = sqlite3MAppendf(db, zMsg, "%s USING PRIMARY KEY", zMsg);
-      }
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-      else if( (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
-        sqlite3_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
-        zMsg = sqlite3MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
-                    pVtabIdx->idxNum, pVtabIdx->idxStr);
-      }
-#endif
-      if( pLevel->plan.wsFlags & WHERE_ORDERBY ){
-        zMsg = sqlite3MAppendf(db, zMsg, "%s ORDER BY", zMsg);
-      }
-      sqlite3VdbeAddOp4(v, OP_Explain, i, pLevel->iFrom, 0, zMsg, P4_DYNAMIC);
-    }
-#endif /* SQLITE_OMIT_EXPLAIN */
     pTabItem = &pTabList->a[pLevel->iFrom];
     pTab = pTabItem->pTab;
-    iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
-    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ) continue;
+    pLevel->iTabCur = pTabItem->iCursor;
+    pWInfo->nRowOut *= pLevel->plan.nRow;
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){
+      /* Do nothing */
+    }else
 #ifndef SQLITE_OMIT_VIRTUALTABLE
     if( (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
       int iCur = pTabItem->iCursor;
-      sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0,
-                        (const char*)pTab->pVtab, P4_VTAB);
+      sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);
     }else
 #endif
     if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
-         && (wctrlFlags & WHERE_OMIT_OPEN)==0 ){
+         && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){
       int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
       sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
+      testcase( pTab->nCol==BMS-1 );
+      testcase( pTab->nCol==BMS );
       if( !pWInfo->okOnePass && pTab->nCol<BMS ){
         Bitmask b = pTabItem->colUsed;
         int n = 0;
         for(; b; b=b>>1, n++){}
-        sqlite3VdbeChangeP2(v, sqlite3VdbeCurrentAddr(v)-2, n);
+        sqlite3VdbeChangeP4(v, sqlite3VdbeCurrentAddr(v)-1, 
+                            SQLITE_INT_TO_PTR(n), P4_INT32);
         assert( n<=pTab->nCol );
       }
     }else{
       sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
     }
-    pLevel->iTabCur = pTabItem->iCursor;
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+    if( (pLevel->plan.wsFlags & WHERE_TEMP_INDEX)!=0 ){
+      constructAutomaticIndex(pParse, pWC, pTabItem, notReady, pLevel);
+    }else
+#endif
     if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
       Index *pIx = pLevel->plan.u.pIdx;
       KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIx);
-      int iIdxCur = pLevel->iIdxCur;
+      int iIndexCur = pLevel->iIdxCur;
       assert( pIx->pSchema==pTab->pSchema );
-      assert( iIdxCur>=0 );
-      sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pIx->nColumn+1);
-      sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIx->tnum, iDb,
+      assert( iIndexCur>=0 );
+      sqlite3VdbeAddOp4(v, OP_OpenRead, iIndexCur, pIx->tnum, iDb,
                         (char*)pKey, P4_KEYINFO_HANDOFF);
       VdbeComment((v, "%s", pIx->zName));
     }
     sqlite3CodeVerifySchema(pParse, iDb);
+    notReady &= ~getMask(pWC->pMaskSet, pTabItem->iCursor);
   }
   pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
+  if( db->mallocFailed ) goto whereBeginError;
 
   /* Generate the code to do the search.  Each iteration of the for
   ** loop below generates code for a single nested loop of the VM
   ** program.
   */
   notReady = ~(Bitmask)0;
-  for(i=0; i<pTabList->nSrc; i++){
+  for(i=0; i<nTabList; i++){
+    pLevel = &pWInfo->a[i];
+    explainOneScan(pParse, pTabList, pLevel, i, pLevel->iFrom, wctrlFlags);
     notReady = codeOneLoopStart(pWInfo, i, wctrlFlags, notReady);
-    pWInfo->iContinue = pWInfo->a[i].addrCont;
+    pWInfo->iContinue = pLevel->addrCont;
   }
 
 #ifdef SQLITE_TEST  /* For testing and debugging use only */
@@ -82724,7 +106770,7 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
   ** the index is listed as "{}".  If the primary key is used the
   ** index name is '*'.
   */
-  for(i=0; i<pTabList->nSrc; i++){
+  for(i=0; i<nTabList; i++){
     char *z;
     int n;
     pLevel = &pWInfo->a[i];
@@ -82773,7 +106819,10 @@ SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
 
   /* Jump here if malloc fails */
 whereBeginError:
-  whereInfoFree(db, pWInfo);
+  if( pWInfo ){
+    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
+    whereInfoFree(db, pWInfo);
+  }
   return 0;
 }
 
@@ -82791,8 +106840,8 @@ SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
 
   /* Generate loop termination code.
   */
-  sqlite3ExprClearColumnCache(pParse, -1);
-  for(i=pTabList->nSrc-1; i>=0; i--){
+  sqlite3ExprCacheClear(pParse);
+  for(i=pWInfo->nLevel-1; i>=0; i--){
     pLevel = &pWInfo->a[i];
     sqlite3VdbeResolveLabel(v, pLevel->addrCont);
     if( pLevel->op!=OP_Noop ){
@@ -82814,11 +106863,19 @@ SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
     if( pLevel->iLeftJoin ){
       int addr;
       addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
-      sqlite3VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
+      assert( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
+           || (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 );
+      if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0 ){
+        sqlite3VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
+      }
       if( pLevel->iIdxCur>=0 ){
         sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
       }
-      sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
+      if( pLevel->op==OP_Return ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
+      }
       sqlite3VdbeJumpHere(v, addr);
     }
   }
@@ -82830,16 +106887,21 @@ SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
 
   /* Close all of the cursors that were opened by sqlite3WhereBegin.
   */
-  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
+  assert( pWInfo->nLevel==1 || pWInfo->nLevel==pTabList->nSrc );
+  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
+    Index *pIdx = 0;
     struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];
     Table *pTab = pTabItem->pTab;
     assert( pTab!=0 );
-    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ) continue;
-    if( (pWInfo->wctrlFlags & WHERE_OMIT_CLOSE)==0 ){
-      if( !pWInfo->okOnePass && (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0 ){
+    if( (pTab->tabFlags & TF_Ephemeral)==0
+     && pTab->pSelect==0
+     && (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
+    ){
+      int ws = pLevel->plan.wsFlags;
+      if( !pWInfo->okOnePass && (ws & WHERE_IDX_ONLY)==0 ){
         sqlite3VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
       }
-      if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
+      if( (ws & WHERE_INDEXED)!=0 && (ws & WHERE_TEMP_INDEX)==0 ){
         sqlite3VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
       }
     }
@@ -82857,13 +106919,15 @@ SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
     ** that reference the table and converts them into opcodes that
     ** reference the index.
     */
-    if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
+    if( pLevel->plan.wsFlags & WHERE_INDEXED ){
+      pIdx = pLevel->plan.u.pIdx;
+    }else if( pLevel->plan.wsFlags & WHERE_MULTI_OR ){
+      pIdx = pLevel->u.pCovidx;
+    }
+    if( pIdx && !db->mallocFailed){
       int k, j, last;
       VdbeOp *pOp;
-      Index *pIdx = pLevel->plan.u.pIdx;
-      int useIndexOnly = pLevel->plan.wsFlags & WHERE_IDX_ONLY;
 
-      assert( pIdx!=0 );
       pOp = sqlite3VdbeGetOp(v, pWInfo->iTop);
       last = sqlite3VdbeCurrentAddr(v);
       for(k=pWInfo->iTop; k<last; k++, pOp++){
@@ -82876,12 +106940,11 @@ SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
               break;
             }
           }
-          assert(!useIndexOnly || j<pIdx->nColumn);
+          assert( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
+               || j<pIdx->nColumn );
         }else if( pOp->opcode==OP_Rowid ){
           pOp->p1 = pLevel->iIdxCur;
           pOp->opcode = OP_IdxRowid;
-        }else if( pOp->opcode==OP_NullRow && useIndexOnly ){
-          pOp->opcode = OP_Noop;
         }
       }
     }
@@ -82889,6 +106952,7 @@ SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
 
   /* Final cleanup
   */
+  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
   whereInfoFree(db, pWInfo);
   return;
 }
@@ -82897,11 +106961,29 @@ SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
 /************** Begin file parse.c *******************************************/
 /* Driver template for the LEMON parser generator.
 ** The author disclaims copyright to this source code.
+**
+** This version of "lempar.c" is modified, slightly, for use by SQLite.
+** The only modifications are the addition of a couple of NEVER()
+** macros to disable tests that are needed in the case of a general
+** LALR(1) grammar but which are always false in the
+** specific grammar used by SQLite.
 */
 /* First off, code is included that follows the "include" declaration
 ** in the input grammar file. */
+/* #include <stdio.h> */
 
 
+/*
+** Disable all error recovery processing in the parser push-down
+** automaton.
+*/
+#define YYNOERRORRECOVERY 1
+
+/*
+** Make yytestcase() the same as testcase()
+*/
+#define yytestcase(X) testcase(X)
+
 /*
 ** An instance of this structure holds information about the
 ** LIMIT clause of a SELECT statement.
@@ -82917,7 +106999,7 @@ struct LimitVal {
 */
 struct LikeOp {
   Token eOperator;  /* "like" or "glob" or "regexp" */
-  int not;         /* True if the NOT keyword is present */
+  int bNot;         /* True if the NOT keyword is present */
 };
 
 /*
@@ -82936,6 +107018,87 @@ struct TrigEvent { int a; IdList * b; };
 */
 struct AttachKey { int type;  Token key; };
 
+/*
+** One or more VALUES claues
+*/
+struct ValueList {
+  ExprList *pList;
+  Select *pSelect;
+};
+
+
+  /* This is a utility routine used to set the ExprSpan.zStart and
+  ** ExprSpan.zEnd values of pOut so that the span covers the complete
+  ** range of text beginning with pStart and going to the end of pEnd.
+  */
+  static void spanSet(ExprSpan *pOut, Token *pStart, Token *pEnd){
+    pOut->zStart = pStart->z;
+    pOut->zEnd = &pEnd->z[pEnd->n];
+  }
+
+  /* Construct a new Expr object from a single identifier.  Use the
+  ** new Expr to populate pOut.  Set the span of pOut to be the identifier
+  ** that created the expression.
+  */
+  static void spanExpr(ExprSpan *pOut, Parse *pParse, int op, Token *pValue){
+    pOut->pExpr = sqlite3PExpr(pParse, op, 0, 0, pValue);
+    pOut->zStart = pValue->z;
+    pOut->zEnd = &pValue->z[pValue->n];
+  }
+
+  /* This routine constructs a binary expression node out of two ExprSpan
+  ** objects and uses the result to populate a new ExprSpan object.
+  */
+  static void spanBinaryExpr(
+    ExprSpan *pOut,     /* Write the result here */
+    Parse *pParse,      /* The parsing context.  Errors accumulate here */
+    int op,             /* The binary operation */
+    ExprSpan *pLeft,    /* The left operand */
+    ExprSpan *pRight    /* The right operand */
+  ){
+    pOut->pExpr = sqlite3PExpr(pParse, op, pLeft->pExpr, pRight->pExpr, 0);
+    pOut->zStart = pLeft->zStart;
+    pOut->zEnd = pRight->zEnd;
+  }
+
+  /* Construct an expression node for a unary postfix operator
+  */
+  static void spanUnaryPostfix(
+    ExprSpan *pOut,        /* Write the new expression node here */
+    Parse *pParse,         /* Parsing context to record errors */
+    int op,                /* The operator */
+    ExprSpan *pOperand,    /* The operand */
+    Token *pPostOp         /* The operand token for setting the span */
+  ){
+    pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
+    pOut->zStart = pOperand->zStart;
+    pOut->zEnd = &pPostOp->z[pPostOp->n];
+  }                           
+
+  /* A routine to convert a binary TK_IS or TK_ISNOT expression into a
+  ** unary TK_ISNULL or TK_NOTNULL expression. */
+  static void binaryToUnaryIfNull(Parse *pParse, Expr *pY, Expr *pA, int op){
+    sqlite3 *db = pParse->db;
+    if( db->mallocFailed==0 && pY->op==TK_NULL ){
+      pA->op = (u8)op;
+      sqlite3ExprDelete(db, pA->pRight);
+      pA->pRight = 0;
+    }
+  }
+
+  /* Construct an expression node for a unary prefix operator
+  */
+  static void spanUnaryPrefix(
+    ExprSpan *pOut,        /* Write the new expression node here */
+    Parse *pParse,         /* Parsing context to record errors */
+    int op,                /* The operator */
+    ExprSpan *pOperand,    /* The operand */
+    Token *pPreOp         /* The operand token for setting the span */
+  ){
+    pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
+    pOut->zStart = pPreOp->z;
+    pOut->zEnd = pOperand->zEnd;
+  }
 /* Next is all token values, in a form suitable for use by makeheaders.
 ** This section will be null unless lemon is run with the -m switch.
 */
@@ -82988,7 +107151,7 @@ struct AttachKey { int type;  Token key; };
 #define YYCODETYPE unsigned char
 #define YYNOCODE 251
 #define YYACTIONTYPE unsigned short int
-#define YYWILDCARD 62
+#define YYWILDCARD 67
 #define sqlite3ParserTOKENTYPE Token
 typedef union {
   int yyinit;
@@ -82998,12 +107161,15 @@ typedef union {
   Select* yy159;
   IdList* yy180;
   struct {int value; int mask;} yy207;
+  u8 yy258;
   struct LikeOp yy318;
   TriggerStep* yy327;
+  ExprSpan yy342;
   SrcList* yy347;
   int yy392;
   struct TrigEvent yy410;
   ExprList* yy442;
+  struct ValueList yy487;
 } YYMINORTYPE;
 #ifndef YYSTACKDEPTH
 #define YYSTACKDEPTH 100
@@ -83012,8 +107178,8 @@ typedef union {
 #define sqlite3ParserARG_PDECL ,Parse *pParse
 #define sqlite3ParserARG_FETCH Parse *pParse = yypParser->pParse
 #define sqlite3ParserARG_STORE yypParser->pParse = pParse
-#define YYNSTATE 610
-#define YYNRULE 319
+#define YYNSTATE 627
+#define YYNRULE 327
 #define YYFALLBACK 1
 #define YY_NO_ACTION      (YYNSTATE+YYNRULE+2)
 #define YY_ACCEPT_ACTION  (YYNSTATE+YYNRULE+1)
@@ -83023,6 +107189,18 @@ typedef union {
 ** YYMINORTYPE objects to zero. */
 static const YYMINORTYPE yyzerominor = { 0 };
 
+/* Define the yytestcase() macro to be a no-op if is not already defined
+** otherwise.
+**
+** Applications can choose to define yytestcase() in the %include section
+** to a macro that can assist in verifying code coverage.  For production
+** code the yytestcase() macro should be turned off.  But it is useful
+** for testing.
+*/
+#ifndef yytestcase
+# define yytestcase(X)
+#endif
+
 
 /* Next are the tables used to determine what action to take based on the
 ** current state and lookahead token.  These tables are used to implement
@@ -83071,430 +107249,475 @@ static const YYMINORTYPE yyzerominor = { 0 };
 **                     shifting non-terminals after a reduce.
 **  yy_default[]       Default action for each state.
 */
+#define YY_ACTTAB_COUNT (1564)
 static const YYACTIONTYPE yy_action[] = {
- /*     0 */   304,  930,  120,  609,    1,  178,  214,  436,   62,   62,
- /*    10 */    62,   62,  216,   64,   64,   64,   64,   65,   65,   66,
- /*    20 */    66,   66,   67,  216,  406,  403,  443,  449,   69,   64,
- /*    30 */    64,   64,   64,   65,   65,   66,   66,   66,   67,  216,
- /*    40 */   469,  467,  336,  174,   61,   60,  309,  453,  454,  450,
- /*    50 */   450,   63,   63,   62,   62,   62,   62,  200,   64,   64,
- /*    60 */    64,   64,   65,   65,   66,   66,   66,   67,  216,  304,
- /*    70 */   510,  312,  436,  509,  438,   83,   64,   64,   64,   64,
- /*    80 */    65,   65,   66,   66,   66,   67,  216,   65,   65,   66,
- /*    90 */    66,   66,   67,  216,  511,  443,  449,  325,  408,   59,
- /*   100 */   465,  218,   57,  213,  411,  496,  428,  440,  440,  440,
- /*   110 */   206,   67,  216,   61,   60,  309,  453,  454,  450,  450,
- /*   120 */    63,   63,   62,   62,   62,   62,  552,   64,   64,   64,
- /*   130 */    64,   65,   65,   66,   66,   66,   67,  216,  304,  228,
- /*   140 */   186,  469,  544,  312,  433,  170,  114,  256,  357,  261,
- /*   150 */   358,  181,  425,   20,  426,  542,  153,   85,  265,  465,
- /*   160 */   218,  150,  151,  539,  443,  449,   95,  311,  394,  412,
- /*   170 */   413,  510,  276,  427,  436,  438,  152,  553,  545,  589,
- /*   180 */   590,  539,   61,   60,  309,  453,  454,  450,  450,   63,
- /*   190 */    63,   62,   62,   62,   62,  402,   64,   64,   64,   64,
- /*   200 */    65,   65,   66,   66,   66,   67,  216,  304,  440,  440,
- /*   210 */   440,  228,  109,  411,  399,  523,  593,  330,  114,  256,
- /*   220 */   357,  261,  358,  181,  187,  330,  485,  359,  362,  363,
- /*   230 */   265,  593,  241,  443,  449,  592,  591,  248,  364,  436,
- /*   240 */   432,   35,  492,   66,   66,   66,   67,  216,  432,   42,
- /*   250 */   592,   61,   60,  309,  453,  454,  450,  450,   63,   63,
- /*   260 */    62,   62,   62,   62,  401,   64,   64,   64,   64,   65,
- /*   270 */    65,   66,   66,   66,   67,  216,  304,  570,  412,  413,
- /*   280 */   187,  501,  344,  359,  362,  363,  215,  354,  346,  221,
- /*   290 */   330,  341,  330,   56,  364,  569,  588,  217,   68,  156,
- /*   300 */    70,  155,  443,  449,   68,  187,   70,  155,  359,  362,
- /*   310 */   363,  397,  217,  432,   35,  432,   36,  148,  569,  364,
- /*   320 */    61,   60,  309,  453,  454,  450,  450,   63,   63,   62,
- /*   330 */    62,   62,   62,  433,   64,   64,   64,   64,   65,   65,
- /*   340 */    66,   66,   66,   67,  216,  387,  282,  281,  330,  304,
- /*   350 */   474,   68,  480,   70,  155,  344,  214,  154,  299,  330,
- /*   360 */   343,  467,  543,  174,  384,  475,  257,  247,  387,  282,
- /*   370 */   281,  432,   28,  411,  160,  443,  449,  258,  476,  214,
- /*   380 */   516,  496,  432,   42,  198,  492,   68,  162,   70,  155,
- /*   390 */   517,  433,   78,   61,   60,  309,  453,  454,  450,  450,
- /*   400 */    63,   63,   62,   62,   62,   62,  595,   64,   64,   64,
- /*   410 */    64,   65,   65,   66,   66,   66,   67,  216,  433,  367,
- /*   420 */   349,  433,  304,  220,  222,  544,  505,  330,  465,  330,
- /*   430 */   230,  330,  240,  163,  161,  554,   20,  431,  412,  413,
- /*   440 */     2,  430,  385,  375,  411,  198,  182,  249,  443,  449,
- /*   450 */   432,   35,  432,   50,  432,   50,  310,  460,  461,   17,
- /*   460 */   207,  335,  460,  461,  388,   81,   61,   60,  309,  453,
- /*   470 */   454,  450,  450,   63,   63,   62,   62,   62,   62,  433,
- /*   480 */    64,   64,   64,   64,   65,   65,   66,   66,   66,   67,
- /*   490 */   216,  304,  348,  504,  433,  508,  531,  486,  320,  353,
- /*   500 */   321,  306,  457,  385,   23,  331,  265,  470,  411,  412,
- /*   510 */   413,  444,  445,  551,  526,  307,  532,  443,  449,  217,
- /*   520 */   550,  496,  432,    3,  217,  381,  607,  921,  333,  921,
- /*   530 */   456,  456,  447,  448,  276,   61,   60,  309,  453,  454,
- /*   540 */   450,  450,   63,   63,   62,   62,   62,   62,  410,   64,
- /*   550 */    64,   64,   64,   65,   65,   66,   66,   66,   67,  216,
- /*   560 */   304,  446,  607,  920,  525,  920,  604,  264,  314,  474,
- /*   570 */   411,  123,  411,  412,  413,  124,  277,  487,  234,  333,
- /*   580 */   411,  456,  456,  319,  475,  411,  443,  449,  333,  377,
- /*   590 */   456,  456,  286,  333,  380,  456,  456,  476,  178,  340,
- /*   600 */   436,  420,  604,  315,   61,   60,  309,  453,  454,  450,
- /*   610 */   450,   63,   63,   62,   62,   62,   62,  330,   64,   64,
- /*   620 */    64,   64,   65,   65,   66,   66,   66,   67,  216,  304,
- /*   630 */   289,    5,  287,  268,  466,  412,  413,  412,  413,  396,
- /*   640 */   432,   29,  503,  330,  159,  412,  413,  610,  406,  403,
- /*   650 */   412,  413,  414,  415,  416,  443,  449,  333,  214,  456,
- /*   660 */   456,  488,  276,  489,   21,  436,  432,   24,  436,  487,
- /*   670 */   514,  515,  395,   61,   60,  309,  453,  454,  450,  450,
- /*   680 */    63,   63,   62,   62,   62,   62,  330,   64,   64,   64,
- /*   690 */    64,   65,   65,   66,   66,   66,   67,  216,  304,  560,
- /*   700 */   374,  560,  352,   94,  578,  330,  567,  515,  330,  432,
- /*   710 */    33,  330,  288,  330,  562,  330,  544,  330,  561,  183,
- /*   720 */   184,  185,  603,  303,  443,  449,  600,   20,  432,   54,
- /*   730 */   376,  432,   53,  436,  432,   99,  432,   97,  432,  102,
- /*   740 */   432,  103,   61,   60,  309,  453,  454,  450,  450,   63,
- /*   750 */    63,   62,   62,   62,   62,  330,   64,   64,   64,   64,
- /*   760 */    65,   65,   66,   66,   66,   67,  216,  304,  330,  405,
- /*   770 */     1,  202,  330,  512,  330,  214,  330,  171,  432,  108,
- /*   780 */   330,  421,  429,  330,  487,  342,  330,  384,   19,  386,
- /*   790 */   145,  432,  110,  443,  449,  432,   16,  432,  100,  432,
- /*   800 */    34,  351,  270,  432,   98,  433,  432,   25,  276,  432,
- /*   810 */    55,   61,   60,  309,  453,  454,  450,  450,   63,   63,
- /*   820 */    62,   62,   62,   62,  330,   64,   64,   64,   64,   65,
- /*   830 */    65,   66,   66,   66,   67,  216,  304,  330,  323,  119,
- /*   840 */   274,  330,  272,  330,  355,  330,  422,  432,  111,  330,
- /*   850 */   580,  159,  115,  233,  330,  177,  161,  439,  463,  463,
- /*   860 */   432,  112,  443,  449,  432,  113,  432,   26,  432,   37,
- /*   870 */   649,  431,  432,   38,  492,  430,  487,  432,   27,  264,
- /*   880 */    61,   71,  309,  453,  454,  450,  450,   63,   63,   62,
- /*   890 */    62,   62,   62,  330,   64,   64,   64,   64,   65,   65,
- /*   900 */    66,   66,   66,   67,  216,  304,  330,  264,  264,  528,
- /*   910 */   330,  157,  330,  252,  330,  229,  432,   39,  330,  482,
- /*   920 */   332,  478,   77,  330,   79,  330,  483,  520,  521,  432,
- /*   930 */    40,  443,  449,  432,   41,  432,   43,  432,   44,  492,
- /*   940 */   491,  432,   45,  316,  317,  433,  432,   30,  432,   31,
- /*   950 */    60,  309,  453,  454,  450,  450,   63,   63,   62,   62,
- /*   960 */    62,   62,  330,   64,   64,   64,   64,   65,   65,   66,
- /*   970 */    66,   66,   67,  216,  304,  330,  264,  564,  254,  330,
- /*   980 */   458,  330,   22,  330,  495,  432,   46,  330,  494,  535,
- /*   990 */   179,  186,  330,  267,  330,  186,  451,  497,  432,   47,
- /*  1000 */   443,  449,  432,   48,  432,   49,  432,   32,  182,  262,
- /*  1010 */   432,   10,  318,  276,  389,  432,   51,  432,   52,  276,
- /*  1020 */   309,  453,  454,  450,  450,   63,   63,   62,   62,   62,
- /*  1030 */    62,  276,   64,   64,   64,   64,   65,   65,   66,   66,
- /*  1040 */    66,   67,  216,  165,  276,  276,  189,  192,  235,  236,
- /*  1050 */   237,  168,  239,  566,  105,  581,   18,  530,  529,   73,
- /*  1060 */   337,  582,    4,  306,  605,  527,  308,  211,  366,  294,
- /*  1070 */   186,  263,  533,  231,  334,  565,  295,  186,  534,  546,
- /*  1080 */   433,  433,  573,  574,  179,   92,  232,  292,  209,  269,
- /*  1090 */   569,  339,  271,  853,  208,  273,  275,  210,  585,  195,
- /*  1100 */    92,  469,  371,  606,  602,    8,  302,  423,  280,  379,
- /*  1110 */   382,  383,  147,  242,  283,  437,  462,  284,  285,  577,
- /*  1120 */   338,   76,   75,  587,  293,  296,  297,  599,  481,  464,
- /*  1130 */    74,  328,  329,  250,  526,  438,  572,  166,  290,  393,
- /*  1140 */   392,  291,  281,  409,  537,  584,  305,  484,  259,  540,
- /*  1150 */   417,  214,  418,  214,  536,  326,  538,  419,  361,  167,
- /*  1160 */    73,  337,  169,    4,    7,  327,  347,  308,  440,  440,
- /*  1170 */   440,  441,  442,   11,   85,  334,  398,   84,  434,  345,
- /*  1180 */   243,   58,  244,   73,  337,   80,    4,  245,  435,  246,
- /*  1190 */   308,  176,  339,  479,   86,  121,  356,  350,  334,  493,
- /*  1200 */   251,  253,  469,  499,  255,  513,  500,  518,  313,  519,
- /*  1210 */   260,  523,  125,  522,  226,  339,  219,  524,  368,  190,
- /*  1220 */   191,  300,   76,   75,  502,  469,  225,  227,  547,  541,
- /*  1230 */   548,   74,  328,  329,  301,  555,  438,  549,  370,  193,
- /*  1240 */   372,  194,  557,   89,  196,   76,   75,  278,  378,  117,
- /*  1250 */   558,  568,  133,  390,   74,  328,  329,  199,  391,  438,
- /*  1260 */   322,  134,  135,  136,  575,  143,  583,  596,  139,  440,
- /*  1270 */   440,  440,  441,  442,   11,  597,  598,  601,  137,  142,
- /*  1280 */   101,  224,  104,  407,  238,  424,  650,  651,   93,  172,
- /*  1290 */    96,  173,  440,  440,  440,  441,  442,   11,  452,  455,
- /*  1300 */    72,  471,  459,  468,  472,  144,  158,    6,  473,  490,
- /*  1310 */   107,  175,  477,   82,   13,  122,   12,  180,  506,  118,
- /*  1320 */   498,  164,  507,  324,  223,   87,  126,  116,  266,  127,
- /*  1330 */    88,  128,  188,  258,  360,  369,  146,  556,  129,  373,
- /*  1340 */   179,  365,  279,  197,  131,  130,  563,    9,  571,  132,
- /*  1350 */   559,  201,   14,  576,  203,  204,  205,  579,  140,  138,
- /*  1360 */   141,   15,  586,  594,  212,  106,  400,  298,  149,  404,
- /*  1370 */   931,  608,   90,   91,
+ /*     0 */   309,  955,  184,  417,    2,  171,  624,  594,   56,   56,
+ /*    10 */    56,   56,   49,   54,   54,   54,   54,   53,   53,   52,
+ /*    20 */    52,   52,   51,  233,  620,  619,  298,  620,  619,  234,
+ /*    30 */   587,  581,   56,   56,   56,   56,   19,   54,   54,   54,
+ /*    40 */    54,   53,   53,   52,   52,   52,   51,  233,  605,   57,
+ /*    50 */    58,   48,  579,  578,  580,  580,   55,   55,   56,   56,
+ /*    60 */    56,   56,  541,   54,   54,   54,   54,   53,   53,   52,
+ /*    70 */    52,   52,   51,  233,  309,  594,  325,  196,  195,  194,
+ /*    80 */    33,   54,   54,   54,   54,   53,   53,   52,   52,   52,
+ /*    90 */    51,  233,  617,  616,  165,  617,  616,  380,  377,  376,
+ /*   100 */   407,  532,  576,  576,  587,  581,  303,  422,  375,   59,
+ /*   110 */    53,   53,   52,   52,   52,   51,  233,   50,   47,  146,
+ /*   120 */   574,  545,   65,   57,   58,   48,  579,  578,  580,  580,
+ /*   130 */    55,   55,   56,   56,   56,   56,  213,   54,   54,   54,
+ /*   140 */    54,   53,   53,   52,   52,   52,   51,  233,  309,  223,
+ /*   150 */   539,  420,  170,  176,  138,  280,  383,  275,  382,  168,
+ /*   160 */   489,  551,  409,  668,  620,  619,  271,  438,  409,  438,
+ /*   170 */   550,  604,   67,  482,  507,  618,  599,  412,  587,  581,
+ /*   180 */   600,  483,  618,  412,  618,  598,   91,  439,  440,  439,
+ /*   190 */   335,  598,   73,  669,  222,  266,  480,   57,   58,   48,
+ /*   200 */   579,  578,  580,  580,   55,   55,   56,   56,   56,   56,
+ /*   210 */   670,   54,   54,   54,   54,   53,   53,   52,   52,   52,
+ /*   220 */    51,  233,  309,  279,  232,  231,    1,  132,  200,  385,
+ /*   230 */   620,  619,  617,  616,  278,  435,  289,  563,  175,  262,
+ /*   240 */   409,  264,  437,  497,  436,  166,  441,  568,  336,  568,
+ /*   250 */   201,  537,  587,  581,  599,  412,  165,  594,  600,  380,
+ /*   260 */   377,  376,  597,  598,   92,  523,  618,  569,  569,  592,
+ /*   270 */   375,   57,   58,   48,  579,  578,  580,  580,   55,   55,
+ /*   280 */    56,   56,   56,   56,  597,   54,   54,   54,   54,   53,
+ /*   290 */    53,   52,   52,   52,   51,  233,  309,  463,  617,  616,
+ /*   300 */   590,  590,  590,  174,  272,  396,  409,  272,  409,  548,
+ /*   310 */   397,  620,  619,   68,  326,  620,  619,  620,  619,  618,
+ /*   320 */   546,  412,  618,  412,  471,  594,  587,  581,  472,  598,
+ /*   330 */    92,  598,   92,   52,   52,   52,   51,  233,  513,  512,
+ /*   340 */   206,  322,  363,  464,  221,   57,   58,   48,  579,  578,
+ /*   350 */   580,  580,   55,   55,   56,   56,   56,   56,  529,   54,
+ /*   360 */    54,   54,   54,   53,   53,   52,   52,   52,   51,  233,
+ /*   370 */   309,  396,  409,  396,  597,  372,  386,  530,  347,  617,
+ /*   380 */   616,  575,  202,  617,  616,  617,  616,  412,  620,  619,
+ /*   390 */   145,  255,  346,  254,  577,  598,   74,  351,   45,  489,
+ /*   400 */   587,  581,  235,  189,  464,  544,  167,  296,  187,  469,
+ /*   410 */   479,   67,   62,   39,  618,  546,  597,  345,  573,   57,
+ /*   420 */    58,   48,  579,  578,  580,  580,   55,   55,   56,   56,
+ /*   430 */    56,   56,    6,   54,   54,   54,   54,   53,   53,   52,
+ /*   440 */    52,   52,   51,  233,  309,  562,  558,  407,  528,  576,
+ /*   450 */   576,  344,  255,  346,  254,  182,  617,  616,  503,  504,
+ /*   460 */   314,  409,  557,  235,  166,  271,  409,  352,  564,  181,
+ /*   470 */   407,  546,  576,  576,  587,  581,  412,  537,  556,  561,
+ /*   480 */   517,  412,  618,  249,  598,   16,    7,   36,  467,  598,
+ /*   490 */    92,  516,  618,   57,   58,   48,  579,  578,  580,  580,
+ /*   500 */    55,   55,   56,   56,   56,   56,  541,   54,   54,   54,
+ /*   510 */    54,   53,   53,   52,   52,   52,   51,  233,  309,  327,
+ /*   520 */   572,  571,  525,  558,  560,  394,  871,  246,  409,  248,
+ /*   530 */   171,  392,  594,  219,  407,  409,  576,  576,  502,  557,
+ /*   540 */   364,  145,  510,  412,  407,  229,  576,  576,  587,  581,
+ /*   550 */   412,  598,   92,  381,  269,  556,  166,  400,  598,   69,
+ /*   560 */   501,  419,  945,  199,  945,  198,  546,   57,   58,   48,
+ /*   570 */   579,  578,  580,  580,   55,   55,   56,   56,   56,   56,
+ /*   580 */   568,   54,   54,   54,   54,   53,   53,   52,   52,   52,
+ /*   590 */    51,  233,  309,  317,  419,  944,  508,  944,  308,  597,
+ /*   600 */   594,  565,  490,  212,  173,  247,  423,  615,  614,  613,
+ /*   610 */   323,  197,  143,  405,  572,  571,  489,   66,   50,   47,
+ /*   620 */   146,  594,  587,  581,  232,  231,  559,  427,   67,  555,
+ /*   630 */    15,  618,  186,  543,  303,  421,   35,  206,  432,  423,
+ /*   640 */   552,   57,   58,   48,  579,  578,  580,  580,   55,   55,
+ /*   650 */    56,   56,   56,   56,  205,   54,   54,   54,   54,   53,
+ /*   660 */    53,   52,   52,   52,   51,  233,  309,  569,  569,  260,
+ /*   670 */   268,  597,   12,  373,  568,  166,  409,  313,  409,  420,
+ /*   680 */   409,  473,  473,  365,  618,   50,   47,  146,  597,  594,
+ /*   690 */   468,  412,  166,  412,  351,  412,  587,  581,   32,  598,
+ /*   700 */    94,  598,   97,  598,   95,  627,  625,  329,  142,   50,
+ /*   710 */    47,  146,  333,  349,  358,   57,   58,   48,  579,  578,
+ /*   720 */   580,  580,   55,   55,   56,   56,   56,   56,  409,   54,
+ /*   730 */    54,   54,   54,   53,   53,   52,   52,   52,   51,  233,
+ /*   740 */   309,  409,  388,  412,  409,   22,  565,  404,  212,  362,
+ /*   750 */   389,  598,  104,  359,  409,  156,  412,  409,  603,  412,
+ /*   760 */   537,  331,  569,  569,  598,  103,  493,  598,  105,  412,
+ /*   770 */   587,  581,  412,  260,  549,  618,   11,  598,  106,  521,
+ /*   780 */   598,  133,  169,  457,  456,  170,   35,  601,  618,   57,
+ /*   790 */    58,   48,  579,  578,  580,  580,   55,   55,   56,   56,
+ /*   800 */    56,   56,  409,   54,   54,   54,   54,   53,   53,   52,
+ /*   810 */    52,   52,   51,  233,  309,  409,  259,  412,  409,   50,
+ /*   820 */    47,  146,  357,  318,  355,  598,  134,  527,  352,  337,
+ /*   830 */   412,  409,  356,  412,  357,  409,  357,  618,  598,   98,
+ /*   840 */   129,  598,  102,  618,  587,  581,  412,   21,  235,  618,
+ /*   850 */   412,  618,  211,  143,  598,  101,   30,  167,  598,   93,
+ /*   860 */   350,  535,  203,   57,   58,   48,  579,  578,  580,  580,
+ /*   870 */    55,   55,   56,   56,   56,   56,  409,   54,   54,   54,
+ /*   880 */    54,   53,   53,   52,   52,   52,   51,  233,  309,  409,
+ /*   890 */   526,  412,  409,  425,  215,  305,  597,  551,  141,  598,
+ /*   900 */   100,   40,  409,   38,  412,  409,  550,  412,  409,  228,
+ /*   910 */   220,  314,  598,   77,  500,  598,   96,  412,  587,  581,
+ /*   920 */   412,  338,  253,  412,  218,  598,  137,  379,  598,  136,
+ /*   930 */    28,  598,  135,  270,  715,  210,  481,   57,   58,   48,
+ /*   940 */   579,  578,  580,  580,   55,   55,   56,   56,   56,   56,
+ /*   950 */   409,   54,   54,   54,   54,   53,   53,   52,   52,   52,
+ /*   960 */    51,  233,  309,  409,  272,  412,  409,  315,  147,  597,
+ /*   970 */   272,  626,    2,  598,   76,  209,  409,  127,  412,  618,
+ /*   980 */   126,  412,  409,  621,  235,  618,  598,   90,  374,  598,
+ /*   990 */    89,  412,  587,  581,   27,  260,  350,  412,  618,  598,
+ /*  1000 */    75,  321,  541,  541,  125,  598,   88,  320,  278,  597,
+ /*  1010 */   618,   57,   46,   48,  579,  578,  580,  580,   55,   55,
+ /*  1020 */    56,   56,   56,   56,  409,   54,   54,   54,   54,   53,
+ /*  1030 */    53,   52,   52,   52,   51,  233,  309,  409,  450,  412,
+ /*  1040 */   164,  284,  282,  272,  609,  424,  304,  598,   87,  370,
+ /*  1050 */   409,  477,  412,  409,  608,  409,  607,  602,  618,  618,
+ /*  1060 */   598,   99,  586,  585,  122,  412,  587,  581,  412,  618,
+ /*  1070 */   412,  618,  618,  598,   86,  366,  598,   17,  598,   85,
+ /*  1080 */   319,  185,  519,  518,  583,  582,   58,   48,  579,  578,
+ /*  1090 */   580,  580,   55,   55,   56,   56,   56,   56,  409,   54,
+ /*  1100 */    54,   54,   54,   53,   53,   52,   52,   52,   51,  233,
+ /*  1110 */   309,  584,  409,  412,  409,  260,  260,  260,  408,  591,
+ /*  1120 */   474,  598,   84,  170,  409,  466,  518,  412,  121,  412,
+ /*  1130 */   618,  618,  618,  618,  618,  598,   83,  598,   72,  412,
+ /*  1140 */   587,  581,   51,  233,  625,  329,  470,  598,   71,  257,
+ /*  1150 */   159,  120,   14,  462,  157,  158,  117,  260,  448,  447,
+ /*  1160 */   446,   48,  579,  578,  580,  580,   55,   55,   56,   56,
+ /*  1170 */    56,   56,  618,   54,   54,   54,   54,   53,   53,   52,
+ /*  1180 */    52,   52,   51,  233,   44,  403,  260,    3,  409,  459,
+ /*  1190 */   260,  413,  619,  118,  398,   10,   25,   24,  554,  348,
+ /*  1200 */   217,  618,  406,  412,  409,  618,    4,   44,  403,  618,
+ /*  1210 */     3,  598,   82,  618,  413,  619,  455,  542,  115,  412,
+ /*  1220 */   538,  401,  536,  274,  506,  406,  251,  598,   81,  216,
+ /*  1230 */   273,  563,  618,  243,  453,  618,  154,  618,  618,  618,
+ /*  1240 */   449,  416,  623,  110,  401,  618,  409,  236,   64,  123,
+ /*  1250 */   487,   41,   42,  531,  563,  204,  409,  267,   43,  411,
+ /*  1260 */   410,  412,  265,  592,  108,  618,  107,  434,  332,  598,
+ /*  1270 */    80,  412,  618,  263,   41,   42,  443,  618,  409,  598,
+ /*  1280 */    70,   43,  411,  410,  433,  261,  592,  149,  618,  597,
+ /*  1290 */   256,  237,  188,  412,  590,  590,  590,  589,  588,   13,
+ /*  1300 */   618,  598,   18,  328,  235,  618,   44,  403,  360,    3,
+ /*  1310 */   418,  461,  339,  413,  619,  227,  124,  590,  590,  590,
+ /*  1320 */   589,  588,   13,  618,  406,  409,  618,  409,  139,   34,
+ /*  1330 */   403,  387,    3,  148,  622,  312,  413,  619,  311,  330,
+ /*  1340 */   412,  460,  412,  401,  180,  353,  412,  406,  598,   79,
+ /*  1350 */   598,   78,  250,  563,  598,    9,  618,  612,  611,  610,
+ /*  1360 */   618,    8,  452,  442,  242,  415,  401,  618,  239,  235,
+ /*  1370 */   179,  238,  428,   41,   42,  288,  563,  618,  618,  618,
+ /*  1380 */    43,  411,  410,  618,  144,  592,  618,  618,  177,   61,
+ /*  1390 */   618,  596,  391,  620,  619,  287,   41,   42,  414,  618,
+ /*  1400 */   293,   30,  393,   43,  411,  410,  292,  618,  592,   31,
+ /*  1410 */   618,  395,  291,   60,  230,   37,  590,  590,  590,  589,
+ /*  1420 */   588,   13,  214,  553,  183,  290,  172,  301,  300,  299,
+ /*  1430 */   178,  297,  595,  563,  451,   29,  285,  390,  540,  590,
+ /*  1440 */   590,  590,  589,  588,   13,  283,  520,  534,  150,  533,
+ /*  1450 */   241,  281,  384,  192,  191,  324,  515,  514,  276,  240,
+ /*  1460 */   510,  523,  307,  511,  128,  592,  509,  225,  226,  486,
+ /*  1470 */   485,  224,  152,  491,  464,  306,  484,  163,  153,  371,
+ /*  1480 */   478,  151,  162,  258,  369,  161,  367,  208,  475,  476,
+ /*  1490 */    26,  160,  465,  140,  361,  131,  590,  590,  590,  116,
+ /*  1500 */   119,  454,  343,  155,  114,  342,  113,  112,  445,  111,
+ /*  1510 */   130,  109,  431,  316,  426,  430,   23,  429,   20,  606,
+ /*  1520 */   190,  507,  255,  341,  244,   63,  294,  593,  310,  570,
+ /*  1530 */   277,  402,  354,  235,  567,  496,  495,  492,  494,  302,
+ /*  1540 */   458,  378,  286,  245,  566,    5,  252,  547,  193,  444,
+ /*  1550 */   233,  340,  207,  524,  368,  505,  334,  522,  499,  399,
+ /*  1560 */   295,  498,  956,  488,
 };
 static const YYCODETYPE yy_lookahead[] = {
- /*     0 */    19,  142,  143,  144,  145,   24,  113,   26,   72,   73,
- /*    10 */    74,   75,   87,   77,   78,   79,   80,   81,   82,   83,
- /*    20 */    84,   85,   86,   87,    1,    2,   45,   46,   76,   77,
- /*    30 */    78,   79,   80,   81,   82,   83,   84,   85,   86,   87,
- /*    40 */    61,  165,  166,  167,   63,   64,   65,   66,   67,   68,
- /*    50 */    69,   70,   71,   72,   73,   74,   75,   25,   77,   78,
- /*    60 */    79,   80,   81,   82,   83,   84,   85,   86,   87,   19,
- /*    70 */    91,   19,   91,  173,   95,   25,   77,   78,   79,   80,
- /*    80 */    81,   82,   83,   84,   85,   86,   87,   81,   82,   83,
- /*    90 */    84,   85,   86,   87,  173,   45,   46,  146,  147,   49,
- /*   100 */    81,   82,   22,  152,   26,  150,   26,  128,  129,  130,
- /*   110 */   159,   86,   87,   63,   64,   65,   66,   67,   68,   69,
- /*   120 */    70,   71,   72,   73,   74,   75,  185,   77,   78,   79,
- /*   130 */    80,   81,   82,   83,   84,   85,   86,   87,   19,   87,
- /*   140 */    25,   61,  150,   19,  193,   93,   94,   95,   96,   97,
- /*   150 */    98,   99,  160,  161,  171,  172,   25,  125,  106,   81,
- /*   160 */    82,   81,   82,  180,   45,   46,   47,  212,  217,   91,
- /*   170 */    92,   91,  150,  172,   26,   95,  184,  185,  185,  101,
- /*   180 */   102,  180,   63,   64,   65,   66,   67,   68,   69,   70,
- /*   190 */    71,   72,   73,   74,   75,  244,   77,   78,   79,   80,
- /*   200 */    81,   82,   83,   84,   85,   86,   87,   19,  128,  129,
- /*   210 */   130,   87,   24,   26,  192,  100,  150,  150,   94,   95,
- /*   220 */    96,   97,   98,   99,   93,  150,   25,   96,   97,   98,
- /*   230 */   106,  150,  194,   45,   46,  169,  170,  150,  107,   91,
- /*   240 */   173,  174,  165,   83,   84,   85,   86,   87,  173,  174,
- /*   250 */   169,   63,   64,   65,   66,   67,   68,   69,   70,   71,
- /*   260 */    72,   73,   74,   75,  242,   77,   78,   79,   80,   81,
- /*   270 */    82,   83,   84,   85,   86,   87,   19,   11,   91,   92,
- /*   280 */    93,  204,  215,   96,   97,   98,  196,  220,  213,  214,
- /*   290 */   150,  190,  150,  203,  107,   52,  230,  231,  221,  159,
- /*   300 */   223,  224,   45,   46,  221,   93,  223,  224,   96,   97,
- /*   310 */    98,  230,  231,  173,  174,  173,  174,  116,   52,  107,
- /*   320 */    63,   64,   65,   66,   67,   68,   69,   70,   71,   72,
- /*   330 */    73,   74,   75,  193,   77,   78,   79,   80,   81,   82,
- /*   340 */    83,   84,   85,   86,   87,  102,  103,  104,  150,   19,
- /*   350 */    12,  221,  222,  223,  224,  215,  113,  159,  162,  150,
- /*   360 */   220,  165,  166,  167,  150,   27,   95,  225,  102,  103,
- /*   370 */   104,  173,  174,   26,  150,   45,   46,  106,   40,  113,
- /*   380 */    42,  150,  173,  174,  159,  165,  221,  159,  223,  224,
- /*   390 */    52,  193,  135,   63,   64,   65,   66,   67,   68,   69,
- /*   400 */    70,   71,   72,   73,   74,   75,  241,   77,   78,   79,
- /*   410 */    80,   81,   82,   83,   84,   85,   86,   87,  193,   19,
- /*   420 */   150,  193,   19,  214,  204,  150,   23,  150,   81,  150,
- /*   430 */   216,  150,  157,  205,  206,  160,  161,  110,   91,   92,
- /*   440 */    22,  114,  217,  212,   26,  159,   46,  150,   45,   46,
- /*   450 */   173,  174,  173,  174,  173,  174,  168,  169,  170,  234,
- /*   460 */   159,  168,  169,  170,  239,  135,   63,   64,   65,   66,
- /*   470 */    67,   68,   69,   70,   71,   72,   73,   74,   75,  193,
- /*   480 */    77,   78,   79,   80,   81,   82,   83,   84,   85,   86,
- /*   490 */    87,   19,  215,   23,  193,   23,   33,  207,  219,  150,
- /*   500 */   219,  101,   23,  217,   22,  150,  106,   23,   26,   91,
- /*   510 */    92,   45,   46,  180,  181,  154,   53,   45,   46,  231,
- /*   520 */   187,  150,  173,  174,  231,  239,   22,   23,  109,   25,
- /*   530 */   111,  112,   66,   67,  150,   63,   64,   65,   66,   67,
- /*   540 */    68,   69,   70,   71,   72,   73,   74,   75,  150,   77,
- /*   550 */    78,   79,   80,   81,   82,   83,   84,   85,   86,   87,
- /*   560 */    19,   95,   22,   23,   23,   25,   62,  150,  105,   12,
- /*   570 */    26,   23,   26,   91,   92,   23,  192,   25,  148,  109,
- /*   580 */    26,  111,  112,  212,   27,   26,   45,   46,  109,  228,
- /*   590 */   111,  112,   17,  109,  233,  111,  112,   40,   24,   42,
- /*   600 */    26,  150,   62,  186,   63,   64,   65,   66,   67,   68,
- /*   610 */    69,   70,   71,   72,   73,   74,   75,  150,   77,   78,
- /*   620 */    79,   80,   81,   82,   83,   84,   85,   86,   87,   19,
- /*   630 */    55,  195,   57,   23,  165,   91,   92,   91,   92,   94,
- /*   640 */   173,  174,   83,  150,   92,   91,   92,    0,    1,    2,
- /*   650 */    91,   92,    7,    8,    9,   45,   46,  109,  113,  111,
- /*   660 */   112,  117,  150,  117,   22,   91,  173,  174,   26,  117,
- /*   670 */   189,  190,  127,   63,   64,   65,   66,   67,   68,   69,
- /*   680 */    70,   71,   72,   73,   74,   75,  150,   77,   78,   79,
- /*   690 */    80,   81,   82,   83,   84,   85,   86,   87,   19,  102,
- /*   700 */   103,  104,   19,   24,  192,  150,  189,  190,  150,  173,
- /*   710 */   174,  150,  137,  150,   28,  150,  150,  150,   32,  102,
- /*   720 */   103,  104,  247,  248,   45,   46,  160,  161,  173,  174,
- /*   730 */    44,  173,  174,   91,  173,  174,  173,  174,  173,  174,
- /*   740 */   173,  174,   63,   64,   65,   66,   67,   68,   69,   70,
- /*   750 */    71,   72,   73,   74,   75,  150,   77,   78,   79,   80,
- /*   760 */    81,   82,   83,   84,   85,   86,   87,   19,  150,  144,
- /*   770 */   145,  159,  150,  164,  150,  113,  150,   22,  173,  174,
- /*   780 */   150,  150,  173,  150,   25,  150,  150,  150,   22,  127,
- /*   790 */    24,  173,  174,   45,   46,  173,  174,  173,  174,  173,
- /*   800 */   174,  118,   17,  173,  174,  193,  173,  174,  150,  173,
- /*   810 */   174,   63,   64,   65,   66,   67,   68,   69,   70,   71,
- /*   820 */    72,   73,   74,   75,  150,   77,   78,   79,   80,   81,
- /*   830 */    82,   83,   84,   85,   86,   87,   19,  150,  245,  246,
- /*   840 */    55,  150,   57,  150,   83,  150,  150,  173,  174,  150,
- /*   850 */   192,   92,  150,  216,  150,  205,  206,  150,  128,  129,
- /*   860 */   173,  174,   45,   46,  173,  174,  173,  174,  173,  174,
- /*   870 */   115,  110,  173,  174,  165,  114,  117,  173,  174,  150,
- /*   880 */    63,   64,   65,   66,   67,   68,   69,   70,   71,   72,
- /*   890 */    73,   74,   75,  150,   77,   78,   79,   80,   81,   82,
- /*   900 */    83,   84,   85,   86,   87,   19,  150,  150,  150,  182,
- /*   910 */   150,  159,  150,  204,  150,  186,  173,  174,  150,   30,
- /*   920 */    19,  150,  134,  150,  136,  150,   37,    7,    8,  173,
- /*   930 */   174,   45,   46,  173,  174,  173,  174,  173,  174,  165,
- /*   940 */   150,  173,  174,  186,  186,  193,  173,  174,  173,  174,
- /*   950 */    64,   65,   66,   67,   68,   69,   70,   71,   72,   73,
- /*   960 */    74,   75,  150,   77,   78,   79,   80,   81,   82,   83,
- /*   970 */    84,   85,   86,   87,   19,  150,  150,   21,  204,  150,
- /*   980 */    23,  150,   25,  150,  150,  173,  174,  150,   23,   23,
- /*   990 */    25,   25,  150,   23,  150,   25,   95,  150,  173,  174,
- /*  1000 */    45,   46,  173,  174,  173,  174,  173,  174,   46,  150,
- /*  1010 */   173,  174,  186,  150,   58,  173,  174,  173,  174,  150,
- /*  1020 */    65,   66,   67,   68,   69,   70,   71,   72,   73,   74,
- /*  1030 */    75,  150,   77,   78,   79,   80,   81,   82,   83,   84,
- /*  1040 */    85,   86,   87,    5,  150,  150,  159,  159,   10,   11,
- /*  1050 */    12,   13,   14,   97,   16,  192,   22,   94,   95,   19,
- /*  1060 */    20,  192,   22,  101,   23,  150,   26,   29,   23,   31,
- /*  1070 */    25,  150,  182,  192,   34,   23,   38,   25,  182,  150,
- /*  1080 */   193,  193,   23,   23,   25,   25,  192,  192,   50,  150,
- /*  1090 */    52,   51,  150,  137,   56,  150,  150,   59,   23,  235,
- /*  1100 */    25,   61,  236,   62,   23,   71,   25,  153,  150,  150,
- /*  1110 */   150,  150,  195,  197,  150,  165,  232,  150,  150,  150,
- /*  1120 */   227,   81,   82,  150,  150,  150,  150,  150,  176,  232,
- /*  1130 */    90,   91,   92,  208,  181,   95,  198,    6,  208,  208,
- /*  1140 */   102,  103,  104,  149,  165,  198,  108,  176,  176,  165,
- /*  1150 */   149,  113,  149,  113,  176,  149,  176,   13,  177,  151,
- /*  1160 */    19,   20,  151,   22,   25,  158,  122,   26,  128,  129,
- /*  1170 */   130,  131,  132,  133,  125,   34,  138,  123,  193,  121,
- /*  1180 */   198,  124,  199,   19,   20,  134,   22,  200,  202,  201,
- /*  1190 */    26,  115,   51,  156,  101,  156,  101,  120,   34,  210,
- /*  1200 */   209,  209,   61,  210,  209,  175,  210,  175,   43,  183,
- /*  1210 */   175,  100,   22,  177,   87,   51,  226,  175,   18,  155,
- /*  1220 */   155,  178,   81,   82,   83,   61,  229,  229,  175,  183,
- /*  1230 */   175,   90,   91,   92,  178,  156,   95,  175,  156,  155,
- /*  1240 */    41,  156,  156,  134,  155,   81,   82,  237,  156,   63,
- /*  1250 */   238,  188,   22,  156,   90,   91,   92,  188,   18,   95,
- /*  1260 */   156,  191,  191,  191,  198,  218,  198,   36,  188,  128,
- /*  1270 */   129,  130,  131,  132,  133,  156,  156,  140,  191,  218,
- /*  1280 */   163,  179,  179,    1,   15,   23,  115,  115,  240,  115,
- /*  1290 */   240,  115,  128,  129,  130,  131,  132,  133,   95,  110,
- /*  1300 */    22,   11,   23,   23,   23,   22,   22,  119,   23,  117,
- /*  1310 */   243,   25,   23,   25,  119,   22,   25,  119,   23,  246,
- /*  1320 */   118,  115,   23,  249,   47,   22,   22,   35,   23,   22,
- /*  1330 */    22,   22,   99,  106,   47,   19,   24,   20,  101,   39,
- /*  1340 */    25,   47,  137,  101,   22,   48,   48,    5,    1,  105,
- /*  1350 */    54,  126,   22,    1,  116,   17,  120,   20,  105,  116,
- /*  1360 */   126,   22,  127,   23,   15,   17,   60,  139,   22,    3,
- /*  1370 */   250,    4,   71,   71,
+ /*     0 */    19,  142,  143,  144,  145,   24,    1,   26,   77,   78,
+ /*    10 */    79,   80,   81,   82,   83,   84,   85,   86,   87,   88,
+ /*    20 */    89,   90,   91,   92,   26,   27,   15,   26,   27,  197,
+ /*    30 */    49,   50,   77,   78,   79,   80,  204,   82,   83,   84,
+ /*    40 */    85,   86,   87,   88,   89,   90,   91,   92,   23,   68,
+ /*    50 */    69,   70,   71,   72,   73,   74,   75,   76,   77,   78,
+ /*    60 */    79,   80,  166,   82,   83,   84,   85,   86,   87,   88,
+ /*    70 */    89,   90,   91,   92,   19,   94,   19,  105,  106,  107,
+ /*    80 */    25,   82,   83,   84,   85,   86,   87,   88,   89,   90,
+ /*    90 */    91,   92,   94,   95,   96,   94,   95,   99,  100,  101,
+ /*   100 */   112,  205,  114,  115,   49,   50,   22,   23,  110,   54,
+ /*   110 */    86,   87,   88,   89,   90,   91,   92,  221,  222,  223,
+ /*   120 */    23,  120,   25,   68,   69,   70,   71,   72,   73,   74,
+ /*   130 */    75,   76,   77,   78,   79,   80,   22,   82,   83,   84,
+ /*   140 */    85,   86,   87,   88,   89,   90,   91,   92,   19,   92,
+ /*   150 */    23,   67,   25,   96,   97,   98,   99,  100,  101,  102,
+ /*   160 */   150,   32,  150,  118,   26,   27,  109,  150,  150,  150,
+ /*   170 */    41,  161,  162,  180,  181,  165,  113,  165,   49,   50,
+ /*   180 */   117,  188,  165,  165,  165,  173,  174,  170,  171,  170,
+ /*   190 */   171,  173,  174,  118,  184,   16,  186,   68,   69,   70,
+ /*   200 */    71,   72,   73,   74,   75,   76,   77,   78,   79,   80,
+ /*   210 */   118,   82,   83,   84,   85,   86,   87,   88,   89,   90,
+ /*   220 */    91,   92,   19,   98,   86,   87,   22,   24,  160,   88,
+ /*   230 */    26,   27,   94,   95,  109,   97,  224,   66,  118,   60,
+ /*   240 */   150,   62,  104,   23,  106,   25,  229,  230,  229,  230,
+ /*   250 */   160,  150,   49,   50,  113,  165,   96,   26,  117,   99,
+ /*   260 */   100,  101,  194,  173,  174,   94,  165,  129,  130,   98,
+ /*   270 */   110,   68,   69,   70,   71,   72,   73,   74,   75,   76,
+ /*   280 */    77,   78,   79,   80,  194,   82,   83,   84,   85,   86,
+ /*   290 */    87,   88,   89,   90,   91,   92,   19,   11,   94,   95,
+ /*   300 */   129,  130,  131,  118,  150,  215,  150,  150,  150,   25,
+ /*   310 */   220,   26,   27,   22,  213,   26,   27,   26,   27,  165,
+ /*   320 */    25,  165,  165,  165,   30,   94,   49,   50,   34,  173,
+ /*   330 */   174,  173,  174,   88,   89,   90,   91,   92,    7,    8,
+ /*   340 */   160,  187,   48,   57,  187,   68,   69,   70,   71,   72,
+ /*   350 */    73,   74,   75,   76,   77,   78,   79,   80,   23,   82,
+ /*   360 */    83,   84,   85,   86,   87,   88,   89,   90,   91,   92,
+ /*   370 */    19,  215,  150,  215,  194,   19,  220,   88,  220,   94,
+ /*   380 */    95,   23,  160,   94,   95,   94,   95,  165,   26,   27,
+ /*   390 */    95,  105,  106,  107,  113,  173,  174,  217,   22,  150,
+ /*   400 */    49,   50,  116,  119,   57,  120,   50,  158,   22,   21,
+ /*   410 */   161,  162,  232,  136,  165,  120,  194,  237,   23,   68,
+ /*   420 */    69,   70,   71,   72,   73,   74,   75,   76,   77,   78,
+ /*   430 */    79,   80,   22,   82,   83,   84,   85,   86,   87,   88,
+ /*   440 */    89,   90,   91,   92,   19,   23,   12,  112,   23,  114,
+ /*   450 */   115,   63,  105,  106,  107,   23,   94,   95,   97,   98,
+ /*   460 */   104,  150,   28,  116,   25,  109,  150,  150,   23,   23,
+ /*   470 */   112,   25,  114,  115,   49,   50,  165,  150,   44,   11,
+ /*   480 */    46,  165,  165,   16,  173,  174,   76,  136,  100,  173,
+ /*   490 */   174,   57,  165,   68,   69,   70,   71,   72,   73,   74,
+ /*   500 */    75,   76,   77,   78,   79,   80,  166,   82,   83,   84,
+ /*   510 */    85,   86,   87,   88,   89,   90,   91,   92,   19,  169,
+ /*   520 */   170,  171,   23,   12,   23,  214,  138,   60,  150,   62,
+ /*   530 */    24,  215,   26,  216,  112,  150,  114,  115,   36,   28,
+ /*   540 */   213,   95,  103,  165,  112,  205,  114,  115,   49,   50,
+ /*   550 */   165,  173,  174,   51,   23,   44,   25,   46,  173,  174,
+ /*   560 */    58,   22,   23,   22,   25,  160,  120,   68,   69,   70,
+ /*   570 */    71,   72,   73,   74,   75,   76,   77,   78,   79,   80,
+ /*   580 */   230,   82,   83,   84,   85,   86,   87,   88,   89,   90,
+ /*   590 */    91,   92,   19,  215,   22,   23,   23,   25,  163,  194,
+ /*   600 */    94,  166,  167,  168,   25,  138,   67,    7,    8,    9,
+ /*   610 */   108,  206,  207,  169,  170,  171,  150,   22,  221,  222,
+ /*   620 */   223,   26,   49,   50,   86,   87,   23,  161,  162,   23,
+ /*   630 */    22,  165,   24,  120,   22,   23,   25,  160,  241,   67,
+ /*   640 */   176,   68,   69,   70,   71,   72,   73,   74,   75,   76,
+ /*   650 */    77,   78,   79,   80,  160,   82,   83,   84,   85,   86,
+ /*   660 */    87,   88,   89,   90,   91,   92,   19,  129,  130,  150,
+ /*   670 */    23,  194,   35,   23,  230,   25,  150,  155,  150,   67,
+ /*   680 */   150,  105,  106,  107,  165,  221,  222,  223,  194,   94,
+ /*   690 */    23,  165,   25,  165,  217,  165,   49,   50,   25,  173,
+ /*   700 */   174,  173,  174,  173,  174,    0,    1,    2,  118,  221,
+ /*   710 */   222,  223,  193,  219,  237,   68,   69,   70,   71,   72,
+ /*   720 */    73,   74,   75,   76,   77,   78,   79,   80,  150,   82,
+ /*   730 */    83,   84,   85,   86,   87,   88,   89,   90,   91,   92,
+ /*   740 */    19,  150,   19,  165,  150,   24,  166,  167,  168,  227,
+ /*   750 */    27,  173,  174,  231,  150,   25,  165,  150,  172,  165,
+ /*   760 */   150,  242,  129,  130,  173,  174,  180,  173,  174,  165,
+ /*   770 */    49,   50,  165,  150,  176,  165,   35,  173,  174,  165,
+ /*   780 */   173,  174,   35,   23,   23,   25,   25,  173,  165,   68,
+ /*   790 */    69,   70,   71,   72,   73,   74,   75,   76,   77,   78,
+ /*   800 */    79,   80,  150,   82,   83,   84,   85,   86,   87,   88,
+ /*   810 */    89,   90,   91,   92,   19,  150,  193,  165,  150,  221,
+ /*   820 */   222,  223,  150,  213,   19,  173,  174,   23,  150,   97,
+ /*   830 */   165,  150,   27,  165,  150,  150,  150,  165,  173,  174,
+ /*   840 */    22,  173,  174,  165,   49,   50,  165,   52,  116,  165,
+ /*   850 */   165,  165,  206,  207,  173,  174,  126,   50,  173,  174,
+ /*   860 */   128,   27,  160,   68,   69,   70,   71,   72,   73,   74,
+ /*   870 */    75,   76,   77,   78,   79,   80,  150,   82,   83,   84,
+ /*   880 */    85,   86,   87,   88,   89,   90,   91,   92,   19,  150,
+ /*   890 */    23,  165,  150,   23,  216,   25,  194,   32,   39,  173,
+ /*   900 */   174,  135,  150,  137,  165,  150,   41,  165,  150,   52,
+ /*   910 */   238,  104,  173,  174,   29,  173,  174,  165,   49,   50,
+ /*   920 */   165,  219,  238,  165,  238,  173,  174,   52,  173,  174,
+ /*   930 */    22,  173,  174,   23,   23,  160,   25,   68,   69,   70,
+ /*   940 */    71,   72,   73,   74,   75,   76,   77,   78,   79,   80,
+ /*   950 */   150,   82,   83,   84,   85,   86,   87,   88,   89,   90,
+ /*   960 */    91,   92,   19,  150,  150,  165,  150,  245,  246,  194,
+ /*   970 */   150,  144,  145,  173,  174,  160,  150,   22,  165,  165,
+ /*   980 */    22,  165,  150,  150,  116,  165,  173,  174,   52,  173,
+ /*   990 */   174,  165,   49,   50,   22,  150,  128,  165,  165,  173,
+ /*  1000 */   174,  187,  166,  166,   22,  173,  174,  187,  109,  194,
+ /*  1010 */   165,   68,   69,   70,   71,   72,   73,   74,   75,   76,
+ /*  1020 */    77,   78,   79,   80,  150,   82,   83,   84,   85,   86,
+ /*  1030 */    87,   88,   89,   90,   91,   92,   19,  150,  193,  165,
+ /*  1040 */   102,  205,  205,  150,  150,  247,  248,  173,  174,   19,
+ /*  1050 */   150,   20,  165,  150,  150,  150,  150,  150,  165,  165,
+ /*  1060 */   173,  174,   49,   50,  104,  165,   49,   50,  165,  165,
+ /*  1070 */   165,  165,  165,  173,  174,   43,  173,  174,  173,  174,
+ /*  1080 */   187,   24,  190,  191,   71,   72,   69,   70,   71,   72,
+ /*  1090 */    73,   74,   75,   76,   77,   78,   79,   80,  150,   82,
+ /*  1100 */    83,   84,   85,   86,   87,   88,   89,   90,   91,   92,
+ /*  1110 */    19,   98,  150,  165,  150,  150,  150,  150,  150,  150,
+ /*  1120 */    59,  173,  174,   25,  150,  190,  191,  165,   53,  165,
+ /*  1130 */   165,  165,  165,  165,  165,  173,  174,  173,  174,  165,
+ /*  1140 */    49,   50,   91,   92,    1,    2,   53,  173,  174,  138,
+ /*  1150 */   104,   22,    5,    1,   35,  118,  127,  150,  193,  193,
+ /*  1160 */   193,   70,   71,   72,   73,   74,   75,   76,   77,   78,
+ /*  1170 */    79,   80,  165,   82,   83,   84,   85,   86,   87,   88,
+ /*  1180 */    89,   90,   91,   92,   19,   20,  150,   22,  150,   27,
+ /*  1190 */   150,   26,   27,  108,  150,   22,   76,   76,  150,   25,
+ /*  1200 */   193,  165,   37,  165,  150,  165,   22,   19,   20,  165,
+ /*  1210 */    22,  173,  174,  165,   26,   27,   23,  150,  119,  165,
+ /*  1220 */   150,   56,  150,  150,  150,   37,   16,  173,  174,  193,
+ /*  1230 */   150,   66,  165,  193,    1,  165,  121,  165,  165,  165,
+ /*  1240 */    20,  146,  147,  119,   56,  165,  150,  152,   16,  154,
+ /*  1250 */   150,   86,   87,   88,   66,  160,  150,  150,   93,   94,
+ /*  1260 */    95,  165,  150,   98,  108,  165,  127,   23,   65,  173,
+ /*  1270 */   174,  165,  165,  150,   86,   87,  128,  165,  150,  173,
+ /*  1280 */   174,   93,   94,   95,   23,  150,   98,   15,  165,  194,
+ /*  1290 */   150,  140,   22,  165,  129,  130,  131,  132,  133,  134,
+ /*  1300 */   165,  173,  174,    3,  116,  165,   19,   20,  150,   22,
+ /*  1310 */     4,  150,  217,   26,   27,  179,  179,  129,  130,  131,
+ /*  1320 */   132,  133,  134,  165,   37,  150,  165,  150,  164,   19,
+ /*  1330 */    20,  150,   22,  246,  149,  249,   26,   27,  249,  244,
+ /*  1340 */   165,  150,  165,   56,    6,  150,  165,   37,  173,  174,
+ /*  1350 */   173,  174,  150,   66,  173,  174,  165,  149,  149,   13,
+ /*  1360 */   165,   25,  150,  150,  150,  149,   56,  165,  150,  116,
+ /*  1370 */   151,  150,  150,   86,   87,  150,   66,  165,  165,  165,
+ /*  1380 */    93,   94,   95,  165,  150,   98,  165,  165,  151,   22,
+ /*  1390 */   165,  194,  150,   26,   27,  150,   86,   87,  159,  165,
+ /*  1400 */   199,  126,  123,   93,   94,   95,  200,  165,   98,  124,
+ /*  1410 */   165,  122,  201,  125,  225,  135,  129,  130,  131,  132,
+ /*  1420 */   133,  134,    5,  157,  157,  202,  118,   10,   11,   12,
+ /*  1430 */    13,   14,  203,   66,   17,  104,  210,  121,  211,  129,
+ /*  1440 */   130,  131,  132,  133,  134,  210,  175,  211,   31,  211,
+ /*  1450 */    33,  210,  104,   86,   87,   47,  175,  183,  175,   42,
+ /*  1460 */   103,   94,  178,  177,   22,   98,  175,   92,  228,  175,
+ /*  1470 */   175,  228,   55,  183,   57,  178,  175,  156,   61,   18,
+ /*  1480 */   157,   64,  156,  235,  157,  156,   45,  157,  236,  157,
+ /*  1490 */   135,  156,  189,   68,  157,  218,  129,  130,  131,   22,
+ /*  1500 */   189,  199,  157,  156,  192,   18,  192,  192,  199,  192,
+ /*  1510 */   218,  189,   40,  157,   38,  157,  240,  157,  240,  153,
+ /*  1520 */   196,  181,  105,  106,  107,  243,  198,  166,  111,  230,
+ /*  1530 */   176,  226,  239,  116,  230,  176,  166,  166,  176,  148,
+ /*  1540 */   199,  177,  209,  209,  166,  196,  239,  208,  185,  199,
+ /*  1550 */    92,  209,  233,  173,  234,  182,  139,  173,  182,  191,
+ /*  1560 */   195,  182,  250,  186,
 };
-#define YY_SHIFT_USE_DFLT (-108)
-#define YY_SHIFT_MAX 404
+#define YY_SHIFT_USE_DFLT (-70)
+#define YY_SHIFT_COUNT (416)
+#define YY_SHIFT_MIN   (-69)
+#define YY_SHIFT_MAX   (1487)
 static const short yy_shift_ofst[] = {
- /*     0 */    23, 1038, 1040,  -19, 1040, 1164, 1164,  187,   78,  243,
- /*    10 */   119, 1164, 1164, 1164, 1164, 1164,  -48,  266,  347,  554,
- /*    20 */   148,   19,   19, -107,   50,  188,  257,  330,  403,  472,
- /*    30 */   541,  610,  679,  748,  817,  748,  748,  748,  748,  748,
- /*    40 */   748,  748,  748,  748,  748,  748,  748,  748,  748,  748,
- /*    50 */   748,  748,  748,  886,  955,  955, 1141, 1164, 1164, 1164,
- /*    60 */  1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164,
- /*    70 */  1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164,
- /*    80 */  1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164, 1164,
- /*    90 */  1164, 1164, 1164, 1164, 1164, 1164, 1164,  -64,  -64,   -1,
- /*   100 */    -1,   52,    6,  160,  400,  956,  554,  554,   25,  148,
- /*   110 */   -75, -108, -108, -108,   80,  124,  338,  338,  504,  540,
- /*   120 */   647,  574,  554,  574,  574,  554,  554,  554,  554,  554,
- /*   130 */   554,  554,  554,  554,  554,  554,  554,  554,  554,  554,
- /*   140 */   554,  554,  545,  662, -107, -107, -107, -108, -108, -108,
- /*   150 */   -21,  -21,  131,  212,  470,  418,  479,  484,  557,  544,
- /*   160 */   546,  482,  548,  552,  559,  645,  554,  554,  554,  554,
- /*   170 */   554,  761,  554,  554,  642,  554,  554,  759,  554,  554,
- /*   180 */   554,  554,  554,  463,  463,  463,  554,  554,  554,  419,
- /*   190 */   554,  554,  419,  554,  686,  597,  554,  554,  419,  554,
- /*   200 */   554,  554,  419,  554,  554,  554,  419,  419,  554,  554,
- /*   210 */   554,  554,  554,  766,  327,  201,  148,  730,  730,  788,
- /*   220 */   889,  889,  683,  889,  962,  889,  148,  889,  148,  115,
- /*   230 */    32,  683,  683,   32, 1131, 1131, 1131, 1131, 1144, 1144,
- /*   240 */  1139, -107, 1049, 1044, 1054, 1058, 1057, 1051, 1076, 1076,
- /*   250 */  1093, 1077, 1093, 1077, 1093, 1077, 1095, 1095, 1165, 1095,
- /*   260 */  1111, 1095, 1190, 1127, 1127, 1165, 1095, 1095, 1095, 1190,
- /*   270 */  1200, 1076, 1200, 1076, 1200, 1076, 1076, 1199, 1109, 1200,
- /*   280 */  1076, 1186, 1186, 1230, 1049, 1076, 1240, 1240, 1240, 1240,
- /*   290 */  1049, 1186, 1230, 1076, 1231, 1231, 1076, 1076, 1137, -108,
- /*   300 */  -108, -108, -108, -108,  466,  575,  617,  785,  755,  901,
- /*   310 */   957,  965,  271,  920,  963,  966,  970, 1045, 1052, 1059,
- /*   320 */  1060, 1075, 1034, 1081, 1041, 1282, 1269, 1262, 1171, 1172,
- /*   330 */  1174, 1176, 1203, 1189, 1278, 1279, 1280, 1283, 1290, 1284,
- /*   340 */  1281, 1286, 1285, 1289, 1288, 1188, 1291, 1195, 1288, 1192,
- /*   350 */  1293, 1198, 1202, 1206, 1295, 1299, 1292, 1277, 1303, 1287,
- /*   360 */  1304, 1305, 1307, 1308, 1294, 1309, 1233, 1227, 1316, 1317,
- /*   370 */  1312, 1237, 1300, 1296, 1297, 1315, 1298, 1205, 1242, 1322,
- /*   380 */  1342, 1347, 1244, 1301, 1302, 1225, 1330, 1238, 1352, 1338,
- /*   390 */  1236, 1337, 1243, 1253, 1234, 1339, 1235, 1340, 1348, 1306,
- /*   400 */  1349, 1228, 1346, 1366, 1367,
+ /*     0 */  1143, 1188, 1417, 1188, 1287, 1287,  138,  138,   -2,  -19,
+ /*    10 */  1287, 1287, 1287, 1287,  347,  362,  129,  129,  795, 1165,
+ /*    20 */  1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287,
+ /*    30 */  1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287,
+ /*    40 */  1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287, 1310, 1287,
+ /*    50 */  1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287, 1287,
+ /*    60 */  1287, 1287,  286,  362,  362,  538,  538,  231, 1253,   55,
+ /*    70 */   721,  647,  573,  499,  425,  351,  277,  203,  869,  869,
+ /*    80 */   869,  869,  869,  869,  869,  869,  869,  869,  869,  869,
+ /*    90 */   869,  869,  869,  943,  869, 1017, 1091, 1091,  -69,  -45,
+ /*   100 */   -45,  -45,  -45,  -45,   -1,   24,  245,  362,  362,  362,
+ /*   110 */   362,  362,  362,  362,  362,  362,  362,  362,  362,  362,
+ /*   120 */   362,  362,  362,  388,  356,  362,  362,  362,  362,  362,
+ /*   130 */   732,  868,  231, 1051, 1458,  -70,  -70,  -70, 1367,   57,
+ /*   140 */   434,  434,  289,  291,  285,    1,  204,  572,  539,  362,
+ /*   150 */   362,  362,  362,  362,  362,  362,  362,  362,  362,  362,
+ /*   160 */   362,  362,  362,  362,  362,  362,  362,  362,  362,  362,
+ /*   170 */   362,  362,  362,  362,  362,  362,  362,  362,  362,  362,
+ /*   180 */   362,  506,  506,  506,  705, 1253, 1253, 1253,  -70,  -70,
+ /*   190 */   -70,  171,  171,  160,  502,  502,  502,  446,  432,  511,
+ /*   200 */   422,  358,  335,  -12,  -12,  -12,  -12,  576,  294,  -12,
+ /*   210 */   -12,  295,  595,  141,  600,  730,  723,  723,  805,  730,
+ /*   220 */   805,  439,  911,  231,  865,  231,  865,  807,  865,  723,
+ /*   230 */   766,  633,  633,  231,  284,   63,  608, 1476, 1308, 1308,
+ /*   240 */  1472, 1472, 1308, 1477, 1425, 1275, 1487, 1487, 1487, 1487,
+ /*   250 */  1308, 1461, 1275, 1477, 1425, 1425, 1308, 1461, 1355, 1441,
+ /*   260 */  1308, 1308, 1461, 1308, 1461, 1308, 1461, 1442, 1348, 1348,
+ /*   270 */  1348, 1408, 1375, 1375, 1442, 1348, 1357, 1348, 1408, 1348,
+ /*   280 */  1348, 1316, 1331, 1316, 1331, 1316, 1331, 1308, 1308, 1280,
+ /*   290 */  1288, 1289, 1285, 1279, 1275, 1253, 1336, 1346, 1346, 1338,
+ /*   300 */  1338, 1338, 1338,  -70,  -70,  -70,  -70,  -70,  -70, 1013,
+ /*   310 */   467,  612,   84,  179,  -28,  870,  410,  761,  760,  667,
+ /*   320 */   650,  531,  220,  361,  331,  125,  127,   97, 1306, 1300,
+ /*   330 */  1270, 1151, 1272, 1203, 1232, 1261, 1244, 1148, 1174, 1139,
+ /*   340 */  1156, 1124, 1220, 1115, 1210, 1233, 1099, 1193, 1184, 1174,
+ /*   350 */  1173, 1029, 1121, 1120, 1085, 1162, 1119, 1037, 1152, 1147,
+ /*   360 */  1129, 1046, 1011, 1093, 1098, 1075, 1061, 1032,  960, 1057,
+ /*   370 */  1031, 1030,  899,  938,  982,  936,  972,  958,  910,  955,
+ /*   380 */   875,  885,  908,  857,  859,  867,  804,  590,  834,  747,
+ /*   390 */   818,  513,  611,  741,  673,  637,  611,  606,  603,  579,
+ /*   400 */   501,  541,  468,  386,  445,  395,  376,  281,  185,  120,
+ /*   410 */    92,   75,   45,  114,   25,   11,    5,
 };
-#define YY_REDUCE_USE_DFLT (-142)
-#define YY_REDUCE_MAX 303
+#define YY_REDUCE_USE_DFLT (-169)
+#define YY_REDUCE_COUNT (308)
+#define YY_REDUCE_MIN   (-168)
+#define YY_REDUCE_MAX   (1391)
 static const short yy_reduce_ofst[] = {
- /*     0 */  -141,  -49,  140,   77,  198,   67,   75,   -8,   66,  225,
- /*    10 */   165,  142,  209,  277,  279,  281,  130,  286,   81,  275,
- /*    20 */   196,  288,  293,  228,   83,   83,   83,   83,   83,   83,
- /*    30 */    83,   83,   83,   83,   83,   83,   83,   83,   83,   83,
- /*    40 */    83,   83,   83,   83,   83,   83,   83,   83,   83,   83,
- /*    50 */    83,   83,   83,   83,   83,   83,  349,  467,  493,  536,
- /*    60 */   555,  558,  561,  563,  565,  567,  605,  618,  622,  624,
- /*    70 */   626,  630,  633,  636,  674,  687,  691,  693,  695,  699,
- /*    80 */   704,  743,  756,  760,  762,  764,  768,  773,  775,  812,
- /*    90 */   825,  829,  831,  833,  837,  842,  844,   83,   83,   83,
- /*   100 */    83,  -17,   83,   83,  333,  361,   22,  566,   83, -124,
- /*   110 */    83,   83,   83,   83,  609,    1,  481,  517,  475,  475,
- /*   120 */   625,  220,  -45,  709,  774,  417,  729,  757,  758,  384,
- /*   130 */   231,  826,  214,  371,  512,  658,  863,  869,  881,  894,
- /*   140 */   637,  895,  301,  612,  752,  887,  888,   90,  650,  593,
- /*   150 */  -100,  -79,  -59,   -7,   38,   87,   38,   38,  101,  224,
- /*   160 */   270,  297,   38,  290,  355,  430,  398,  451,  631,  696,
- /*   170 */   702,  436,  355,  707,  469,  635,  771,  290,  790,  834,
- /*   180 */   847,  859,  915,  727,  890,  896,  921,  929,  939,   38,
- /*   190 */   942,  945,   38,  946,  864,  866,  958,  959,   38,  960,
- /*   200 */   961,  964,   38,  967,  968,  969,   38,   38,  973,  974,
- /*   210 */   975,  976,  977,  954,  917,  916,  950,  884,  897,  893,
- /*   220 */   952,  971,  925,  972,  953,  978,  979,  980,  984,  981,
- /*   230 */   938,  930,  931,  947,  994, 1001, 1003, 1006, 1008, 1011,
- /*   240 */  1007,  985,  982,  983,  987,  988,  986,  990, 1037, 1039,
- /*   250 */   991,  989,  992,  993,  995,  996, 1030, 1032, 1026, 1035,
- /*   260 */  1036, 1042, 1043,  997,  998, 1046, 1053, 1055, 1062, 1056,
- /*   270 */  1064, 1079, 1065, 1082, 1084, 1085, 1086, 1010, 1012, 1089,
- /*   280 */  1092, 1063, 1069, 1047, 1066, 1097, 1070, 1071, 1072, 1087,
- /*   290 */  1068, 1080, 1061, 1104, 1048, 1050, 1119, 1120, 1067, 1117,
- /*   300 */  1102, 1103, 1073, 1074,
+ /*     0 */  -141,   90, 1095,  222,  158,  156,   19,   17,   10, -104,
+ /*    10 */   378,  316,  311,   12,  180,  249,  598,  464,  397, 1181,
+ /*    20 */  1177, 1175, 1128, 1106, 1096, 1054, 1038,  974,  964,  962,
+ /*    30 */   948,  905,  903,  900,  887,  874,  832,  826,  816,  813,
+ /*    40 */   800,  758,  755,  752,  742,  739,  726,  685,  681,  668,
+ /*    50 */   665,  652,  607,  604,  594,  591,  578,  530,  528,  526,
+ /*    60 */   385,   18,  477,  466,  519,  444,  350,  435,  405,  488,
+ /*    70 */   488,  488,  488,  488,  488,  488,  488,  488,  488,  488,
+ /*    80 */   488,  488,  488,  488,  488,  488,  488,  488,  488,  488,
+ /*    90 */   488,  488,  488,  488,  488,  488,  488,  488,  488,  488,
+ /*   100 */   488,  488,  488,  488,  488,  488,  488, 1040,  678, 1036,
+ /*   110 */  1007,  967,  966,  965,  845,  686,  610,  684,  317,  672,
+ /*   120 */   893,  327,  623,  522,   -7,  820,  814,  157,  154,  101,
+ /*   130 */   702,  494,  580,  488,  488,  488,  488,  488,  614,  586,
+ /*   140 */   935,  892,  968, 1245, 1242, 1234, 1225,  798,  798, 1222,
+ /*   150 */  1221, 1218, 1214, 1213, 1212, 1202, 1195, 1191, 1161, 1158,
+ /*   160 */  1140, 1135, 1123, 1112, 1107, 1100, 1080, 1074, 1073, 1072,
+ /*   170 */  1070, 1067, 1048, 1044,  969,  968,  907,  906,  904,  894,
+ /*   180 */   833,  837,  836,  340,  827,  815,  775,   68,  722,  646,
+ /*   190 */  -168, 1384, 1380, 1377, 1379, 1376, 1373, 1339, 1365, 1368,
+ /*   200 */  1365, 1365, 1365, 1365, 1365, 1365, 1365, 1320, 1319, 1365,
+ /*   210 */  1365, 1339, 1378, 1349, 1391, 1350, 1342, 1334, 1307, 1341,
+ /*   220 */  1293, 1364, 1363, 1371, 1362, 1370, 1359, 1340, 1354, 1333,
+ /*   230 */  1305, 1304, 1299, 1361, 1328, 1324, 1366, 1282, 1360, 1358,
+ /*   240 */  1278, 1276, 1356, 1292, 1322, 1309, 1317, 1315, 1314, 1312,
+ /*   250 */  1345, 1347, 1302, 1277, 1311, 1303, 1337, 1335, 1252, 1248,
+ /*   260 */  1332, 1330, 1329, 1327, 1326, 1323, 1321, 1297, 1301, 1295,
+ /*   270 */  1294, 1290, 1243, 1240, 1284, 1291, 1286, 1283, 1274, 1281,
+ /*   280 */  1271, 1238, 1241, 1236, 1235, 1227, 1226, 1267, 1266, 1189,
+ /*   290 */  1229, 1223, 1211, 1206, 1201, 1197, 1239, 1237, 1219, 1216,
+ /*   300 */  1209, 1208, 1185, 1089, 1086, 1087, 1137, 1136, 1164,
 };
 static const YYACTIONTYPE yy_default[] = {
- /*     0 */   615,  929,  848,  736,  929,  848,  929,  929,  875,  929,
- /*    10 */   904,  846,  929,  929,  929,  929,  820,  929,  875,  929,
- /*    20 */   652,  875,  875,  740,  771,  929,  929,  929,  929,  929,
- /*    30 */   929,  929,  929,  772,  929,  850,  845,  841,  843,  842,
- /*    40 */   849,  773,  762,  769,  776,  751,  888,  778,  779,  785,
- /*    50 */   786,  905,  903,  808,  807,  826,  929,  929,  929,  929,
- /*    60 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*    70 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*    80 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*    90 */   929,  929,  929,  929,  929,  929,  929,  810,  832,  809,
- /*   100 */   819,  645,  811,  812,  705,  640,  929,  929,  813,  929,
- /*   110 */   814,  827,  828,  829,  929,  929,  929,  929,  929,  929,
- /*   120 */   615,  736,  929,  736,  736,  929,  929,  929,  929,  929,
- /*   130 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*   140 */   929,  929,  929,  929,  929,  929,  929,  730,  740,  922,
- /*   150 */   929,  929,  696,  929,  929,  929,  929,  929,  929,  929,
- /*   160 */   929,  929,  929,  929,  929,  623,  621,  929,  929,  929,
- /*   170 */   929,  728,  929,  929,  654,  929,  929,  738,  929,  929,
- /*   180 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  642,
- /*   190 */   929,  929,  717,  929,  881,  929,  929,  929,  895,  929,
- /*   200 */   929,  929,  893,  929,  929,  929,  719,  781,  861,  929,
- /*   210 */   908,  910,  929,  929,  728,  737,  929,  929,  929,  844,
- /*   220 */   765,  765,  753,  765,  675,  765,  929,  765,  929,  678,
- /*   230 */   775,  753,  753,  775,  620,  620,  620,  620,  631,  631,
- /*   240 */   695,  929,  775,  766,  768,  758,  770,  929,  744,  744,
- /*   250 */   752,  757,  752,  757,  752,  757,  707,  707,  692,  707,
- /*   260 */   678,  707,  854,  858,  858,  692,  707,  707,  707,  854,
- /*   270 */   637,  744,  637,  744,  637,  744,  744,  885,  887,  637,
- /*   280 */   744,  709,  709,  787,  775,  744,  716,  716,  716,  716,
- /*   290 */   775,  709,  787,  744,  907,  907,  744,  744,  915,  662,
- /*   300 */   680,  680,  922,  927,  929,  929,  929,  929,  794,  929,
- /*   310 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*   320 */   929,  929,  868,  929,  929,  929,  629,  929,  799,  795,
- /*   330 */   929,  796,  929,  722,  929,  929,  929,  929,  929,  929,
- /*   340 */   929,  929,  929,  929,  847,  929,  759,  929,  767,  929,
- /*   350 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*   360 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*   370 */   929,  929,  929,  929,  883,  884,  929,  929,  929,  929,
- /*   380 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  929,
- /*   390 */   929,  929,  929,  929,  929,  929,  929,  929,  929,  914,
- /*   400 */   929,  929,  917,  616,  929,  611,  613,  614,  618,  619,
- /*   410 */   622,  649,  650,  651,  624,  625,  626,  627,  628,  630,
- /*   420 */   634,  632,  633,  635,  641,  643,  661,  663,  647,  665,
- /*   430 */   726,  727,  791,  720,  721,  725,  648,  802,  793,  797,
- /*   440 */   798,  800,  801,  815,  816,  818,  824,  831,  834,  817,
- /*   450 */   822,  823,  825,  830,  833,  723,  724,  837,  655,  656,
- /*   460 */   659,  660,  871,  873,  872,  874,  658,  657,  803,  806,
- /*   470 */   839,  840,  896,  897,  898,  899,  900,  835,  745,  838,
- /*   480 */   821,  760,  763,  764,  761,  729,  739,  747,  748,  749,
- /*   490 */   750,  734,  735,  741,  756,  789,  790,  754,  755,  742,
- /*   500 */   743,  731,  732,  733,  836,  792,  804,  805,  666,  667,
- /*   510 */   799,  668,  669,  670,  708,  711,  712,  713,  671,  690,
- /*   520 */   693,  694,  672,  679,  673,  674,  681,  682,  683,  686,
- /*   530 */   687,  688,  689,  684,  685,  855,  856,  859,  857,  676,
- /*   540 */   677,  691,  664,  653,  646,  697,  700,  701,  702,  703,
- /*   550 */   704,  706,  698,  699,  644,  636,  638,  746,  877,  886,
- /*   560 */   882,  878,  879,  880,  639,  851,  852,  710,  783,  784,
- /*   570 */   876,  889,  891,  788,  892,  894,  890,  919,  714,  715,
- /*   580 */   718,  860,  901,  774,  777,  780,  782,  862,  863,  864,
- /*   590 */   865,  866,  869,  870,  867,  902,  906,  909,  911,  912,
- /*   600 */   913,  916,  918,  923,  924,  925,  928,  926,  617,  612,
+ /*     0 */   632,  866,  954,  954,  866,  866,  954,  954,  954,  756,
+ /*    10 */   954,  954,  954,  864,  954,  954,  784,  784,  928,  954,
+ /*    20 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*    30 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*    40 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*    50 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*    60 */   954,  954,  954,  954,  954,  954,  954,  671,  760,  790,
+ /*    70 */   954,  954,  954,  954,  954,  954,  954,  954,  927,  929,
+ /*    80 */   798,  797,  907,  771,  795,  788,  792,  867,  860,  861,
+ /*    90 */   859,  863,  868,  954,  791,  827,  844,  826,  838,  843,
+ /*   100 */   850,  842,  839,  829,  828,  830,  831,  954,  954,  954,
+ /*   110 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*   120 */   954,  954,  954,  658,  725,  954,  954,  954,  954,  954,
+ /*   130 */   954,  954,  954,  832,  833,  847,  846,  845,  954,  663,
+ /*   140 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*   150 */   934,  932,  954,  879,  954,  954,  954,  954,  954,  954,
+ /*   160 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*   170 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*   180 */   638,  756,  756,  756,  632,  954,  954,  954,  946,  760,
+ /*   190 */   750,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*   200 */   954,  954,  954,  800,  739,  917,  919,  954,  900,  737,
+ /*   210 */   660,  758,  673,  748,  640,  794,  773,  773,  912,  794,
+ /*   220 */   912,  696,  719,  954,  784,  954,  784,  693,  784,  773,
+ /*   230 */   862,  954,  954,  954,  757,  748,  954,  939,  764,  764,
+ /*   240 */   931,  931,  764,  806,  729,  794,  736,  736,  736,  736,
+ /*   250 */   764,  655,  794,  806,  729,  729,  764,  655,  906,  904,
+ /*   260 */   764,  764,  655,  764,  655,  764,  655,  872,  727,  727,
+ /*   270 */   727,  711,  876,  876,  872,  727,  696,  727,  711,  727,
+ /*   280 */   727,  777,  772,  777,  772,  777,  772,  764,  764,  954,
+ /*   290 */   789,  778,  787,  785,  794,  954,  714,  648,  648,  637,
+ /*   300 */   637,  637,  637,  951,  951,  946,  698,  698,  681,  954,
+ /*   310 */   954,  954,  954,  954,  954,  954,  881,  954,  954,  954,
+ /*   320 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  633,
+ /*   330 */   941,  954,  954,  938,  954,  954,  954,  954,  799,  954,
+ /*   340 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  916,
+ /*   350 */   954,  954,  954,  954,  954,  954,  954,  910,  954,  954,
+ /*   360 */   954,  954,  954,  954,  903,  902,  954,  954,  954,  954,
+ /*   370 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*   380 */   954,  954,  954,  954,  954,  954,  954,  954,  954,  954,
+ /*   390 */   954,  954,  786,  954,  779,  954,  865,  954,  954,  954,
+ /*   400 */   954,  954,  954,  954,  954,  954,  954,  742,  815,  954,
+ /*   410 */   814,  818,  813,  665,  954,  646,  954,  629,  634,  950,
+ /*   420 */   953,  952,  949,  948,  947,  942,  940,  937,  936,  935,
+ /*   430 */   933,  930,  926,  885,  883,  890,  889,  888,  887,  886,
+ /*   440 */   884,  882,  880,  801,  796,  793,  925,  878,  738,  735,
+ /*   450 */   734,  654,  943,  909,  918,  805,  804,  807,  915,  914,
+ /*   460 */   913,  911,  908,  895,  803,  802,  730,  870,  869,  657,
+ /*   470 */   899,  898,  897,  901,  905,  896,  766,  656,  653,  662,
+ /*   480 */   717,  718,  726,  724,  723,  722,  721,  720,  716,  664,
+ /*   490 */   672,  710,  695,  694,  875,  877,  874,  873,  703,  702,
+ /*   500 */   708,  707,  706,  705,  704,  701,  700,  699,  692,  691,
+ /*   510 */   697,  690,  713,  712,  709,  689,  733,  732,  731,  728,
+ /*   520 */   688,  687,  686,  818,  685,  684,  824,  823,  811,  854,
+ /*   530 */   753,  752,  751,  763,  762,  775,  774,  809,  808,  776,
+ /*   540 */   761,  755,  754,  770,  769,  768,  767,  759,  749,  781,
+ /*   550 */   783,  782,  780,  856,  765,  853,  924,  923,  922,  921,
+ /*   560 */   920,  858,  857,  825,  822,  676,  677,  893,  892,  894,
+ /*   570 */   891,  679,  678,  675,  674,  855,  744,  743,  851,  848,
+ /*   580 */   840,  836,  852,  849,  841,  837,  835,  834,  820,  819,
+ /*   590 */   817,  816,  812,  821,  667,  745,  741,  740,  810,  747,
+ /*   600 */   746,  683,  682,  680,  661,  659,  652,  650,  649,  651,
+ /*   610 */   647,  645,  644,  643,  642,  641,  670,  669,  668,  666,
+ /*   620 */   665,  639,  636,  635,  631,  630,  628,
 };
-#define YY_SZ_ACTTAB (int)(sizeof(yy_action)/sizeof(yy_action[0]))
 
 /* The next table maps tokens into fallback tokens.  If a construct
 ** like the following:
@@ -83520,12 +107743,12 @@ static const YYCODETYPE yyFallback[] = {
    26,  /*  EXCLUSIVE => ID */
     0,  /*     COMMIT => nothing */
    26,  /*        END => ID */
-    0,  /*   ROLLBACK => nothing */
-    0,  /*  SAVEPOINT => nothing */
-    0,  /*    RELEASE => nothing */
+   26,  /*   ROLLBACK => ID */
+   26,  /*  SAVEPOINT => ID */
+   26,  /*    RELEASE => ID */
     0,  /*         TO => nothing */
-    0,  /*     CREATE => nothing */
     0,  /*      TABLE => nothing */
+    0,  /*     CREATE => nothing */
    26,  /*         IF => ID */
     0,  /*        NOT => nothing */
     0,  /*     EXISTS => nothing */
@@ -83535,14 +107758,18 @@ static const YYCODETYPE yyFallback[] = {
     0,  /*         AS => nothing */
     0,  /*      COMMA => nothing */
     0,  /*         ID => nothing */
+    0,  /*    INDEXED => nothing */
    26,  /*      ABORT => ID */
+   26,  /*     ACTION => ID */
    26,  /*      AFTER => ID */
    26,  /*    ANALYZE => ID */
    26,  /*        ASC => ID */
    26,  /*     ATTACH => ID */
    26,  /*     BEFORE => ID */
+   26,  /*         BY => ID */
    26,  /*    CASCADE => ID */
    26,  /*       CAST => ID */
+   26,  /*   COLUMNKW => ID */
    26,  /*   CONFLICT => ID */
    26,  /*   DATABASE => ID */
    26,  /*       DESC => ID */
@@ -83555,6 +107782,7 @@ static const YYCODETYPE yyFallback[] = {
    26,  /*    INSTEAD => ID */
    26,  /*    LIKE_KW => ID */
    26,  /*      MATCH => ID */
+   26,  /*         NO => ID */
    26,  /*        KEY => ID */
    26,  /*         OF => ID */
    26,  /*     OFFSET => ID */
@@ -83570,85 +107798,6 @@ static const YYCODETYPE yyFallback[] = {
    26,  /*    REINDEX => ID */
    26,  /*     RENAME => ID */
    26,  /*   CTIME_KW => ID */
-    0,  /*        ANY => nothing */
-    0,  /*         OR => nothing */
-    0,  /*        AND => nothing */
-    0,  /*         IS => nothing */
-    0,  /*    BETWEEN => nothing */
-    0,  /*         IN => nothing */
-    0,  /*     ISNULL => nothing */
-    0,  /*    NOTNULL => nothing */
-    0,  /*         NE => nothing */
-    0,  /*         EQ => nothing */
-    0,  /*         GT => nothing */
-    0,  /*         LE => nothing */
-    0,  /*         LT => nothing */
-    0,  /*         GE => nothing */
-    0,  /*     ESCAPE => nothing */
-    0,  /*     BITAND => nothing */
-    0,  /*      BITOR => nothing */
-    0,  /*     LSHIFT => nothing */
-    0,  /*     RSHIFT => nothing */
-    0,  /*       PLUS => nothing */
-    0,  /*      MINUS => nothing */
-    0,  /*       STAR => nothing */
-    0,  /*      SLASH => nothing */
-    0,  /*        REM => nothing */
-    0,  /*     CONCAT => nothing */
-    0,  /*    COLLATE => nothing */
-    0,  /*     UMINUS => nothing */
-    0,  /*      UPLUS => nothing */
-    0,  /*     BITNOT => nothing */
-    0,  /*     STRING => nothing */
-    0,  /*    JOIN_KW => nothing */
-    0,  /* CONSTRAINT => nothing */
-    0,  /*    DEFAULT => nothing */
-    0,  /*       NULL => nothing */
-    0,  /*    PRIMARY => nothing */
-    0,  /*     UNIQUE => nothing */
-    0,  /*      CHECK => nothing */
-    0,  /* REFERENCES => nothing */
-    0,  /*   AUTOINCR => nothing */
-    0,  /*         ON => nothing */
-    0,  /*     DELETE => nothing */
-    0,  /*     UPDATE => nothing */
-    0,  /*     INSERT => nothing */
-    0,  /*        SET => nothing */
-    0,  /* DEFERRABLE => nothing */
-    0,  /*    FOREIGN => nothing */
-    0,  /*       DROP => nothing */
-    0,  /*      UNION => nothing */
-    0,  /*        ALL => nothing */
-    0,  /*     EXCEPT => nothing */
-    0,  /*  INTERSECT => nothing */
-    0,  /*     SELECT => nothing */
-    0,  /*   DISTINCT => nothing */
-    0,  /*        DOT => nothing */
-    0,  /*       FROM => nothing */
-    0,  /*       JOIN => nothing */
-    0,  /*    INDEXED => nothing */
-    0,  /*         BY => nothing */
-    0,  /*      USING => nothing */
-    0,  /*      ORDER => nothing */
-    0,  /*      GROUP => nothing */
-    0,  /*     HAVING => nothing */
-    0,  /*      LIMIT => nothing */
-    0,  /*      WHERE => nothing */
-    0,  /*       INTO => nothing */
-    0,  /*     VALUES => nothing */
-    0,  /*    INTEGER => nothing */
-    0,  /*      FLOAT => nothing */
-    0,  /*       BLOB => nothing */
-    0,  /*   REGISTER => nothing */
-    0,  /*   VARIABLE => nothing */
-    0,  /*       CASE => nothing */
-    0,  /*       WHEN => nothing */
-    0,  /*       THEN => nothing */
-    0,  /*       ELSE => nothing */
-    0,  /*      INDEX => nothing */
-    0,  /*      ALTER => nothing */
-    0,  /*        ADD => nothing */
-    0,  /*   COLUMNKW => nothing */
 };
 #endif /* YYFALLBACK */
 
@@ -83692,6 +107841,7 @@ struct yyParser {
 typedef struct yyParser yyParser;
 
 #ifndef NDEBUG
+/* #include <stdio.h> */
 static FILE *yyTraceFILE = 0;
 static char *yyTracePrompt = 0;
 #endif /* NDEBUG */
@@ -83730,62 +107880,62 @@ static const char *const yyTokenName[] = {
   "PLAN",          "BEGIN",         "TRANSACTION",   "DEFERRED",    
   "IMMEDIATE",     "EXCLUSIVE",     "COMMIT",        "END",         
   "ROLLBACK",      "SAVEPOINT",     "RELEASE",       "TO",          
-  "CREATE",        "TABLE",         "IF",            "NOT",         
+  "TABLE",         "CREATE",        "IF",            "NOT",         
   "EXISTS",        "TEMP",          "LP",            "RP",          
-  "AS",            "COMMA",         "ID",            "ABORT",       
-  "AFTER",         "ANALYZE",       "ASC",           "ATTACH",      
-  "BEFORE",        "CASCADE",       "CAST",          "CONFLICT",    
+  "AS",            "COMMA",         "ID",            "INDEXED",     
+  "ABORT",         "ACTION",        "AFTER",         "ANALYZE",     
+  "ASC",           "ATTACH",        "BEFORE",        "BY",          
+  "CASCADE",       "CAST",          "COLUMNKW",      "CONFLICT",    
   "DATABASE",      "DESC",          "DETACH",        "EACH",        
   "FAIL",          "FOR",           "IGNORE",        "INITIALLY",   
-  "INSTEAD",       "LIKE_KW",       "MATCH",         "KEY",         
-  "OF",            "OFFSET",        "PRAGMA",        "RAISE",       
-  "REPLACE",       "RESTRICT",      "ROW",           "TRIGGER",     
-  "VACUUM",        "VIEW",          "VIRTUAL",       "REINDEX",     
-  "RENAME",        "CTIME_KW",      "ANY",           "OR",          
-  "AND",           "IS",            "BETWEEN",       "IN",          
-  "ISNULL",        "NOTNULL",       "NE",            "EQ",          
-  "GT",            "LE",            "LT",            "GE",          
-  "ESCAPE",        "BITAND",        "BITOR",         "LSHIFT",      
-  "RSHIFT",        "PLUS",          "MINUS",         "STAR",        
-  "SLASH",         "REM",           "CONCAT",        "COLLATE",     
-  "UMINUS",        "UPLUS",         "BITNOT",        "STRING",      
-  "JOIN_KW",       "CONSTRAINT",    "DEFAULT",       "NULL",        
-  "PRIMARY",       "UNIQUE",        "CHECK",         "REFERENCES",  
-  "AUTOINCR",      "ON",            "DELETE",        "UPDATE",      
-  "INSERT",        "SET",           "DEFERRABLE",    "FOREIGN",     
-  "DROP",          "UNION",         "ALL",           "EXCEPT",      
-  "INTERSECT",     "SELECT",        "DISTINCT",      "DOT",         
-  "FROM",          "JOIN",          "INDEXED",       "BY",          
-  "USING",         "ORDER",         "GROUP",         "HAVING",      
-  "LIMIT",         "WHERE",         "INTO",          "VALUES",      
-  "INTEGER",       "FLOAT",         "BLOB",          "REGISTER",    
-  "VARIABLE",      "CASE",          "WHEN",          "THEN",        
-  "ELSE",          "INDEX",         "ALTER",         "ADD",         
-  "COLUMNKW",      "error",         "input",         "cmdlist",     
+  "INSTEAD",       "LIKE_KW",       "MATCH",         "NO",          
+  "KEY",           "OF",            "OFFSET",        "PRAGMA",      
+  "RAISE",         "REPLACE",       "RESTRICT",      "ROW",         
+  "TRIGGER",       "VACUUM",        "VIEW",          "VIRTUAL",     
+  "REINDEX",       "RENAME",        "CTIME_KW",      "ANY",         
+  "OR",            "AND",           "IS",            "BETWEEN",     
+  "IN",            "ISNULL",        "NOTNULL",       "NE",          
+  "EQ",            "GT",            "LE",            "LT",          
+  "GE",            "ESCAPE",        "BITAND",        "BITOR",       
+  "LSHIFT",        "RSHIFT",        "PLUS",          "MINUS",       
+  "STAR",          "SLASH",         "REM",           "CONCAT",      
+  "COLLATE",       "BITNOT",        "STRING",        "JOIN_KW",     
+  "CONSTRAINT",    "DEFAULT",       "NULL",          "PRIMARY",     
+  "UNIQUE",        "CHECK",         "REFERENCES",    "AUTOINCR",    
+  "ON",            "INSERT",        "DELETE",        "UPDATE",      
+  "SET",           "DEFERRABLE",    "FOREIGN",       "DROP",        
+  "UNION",         "ALL",           "EXCEPT",        "INTERSECT",   
+  "SELECT",        "DISTINCT",      "DOT",           "FROM",        
+  "JOIN",          "USING",         "ORDER",         "GROUP",       
+  "HAVING",        "LIMIT",         "WHERE",         "INTO",        
+  "VALUES",        "INTEGER",       "FLOAT",         "BLOB",        
+  "REGISTER",      "VARIABLE",      "CASE",          "WHEN",        
+  "THEN",          "ELSE",          "INDEX",         "ALTER",       
+  "ADD",           "error",         "input",         "cmdlist",     
   "ecmd",          "explain",       "cmdx",          "cmd",         
   "transtype",     "trans_opt",     "nm",            "savepoint_opt",
-  "create_table",  "create_table_args",  "temp",          "ifnotexists", 
-  "dbnm",          "columnlist",    "conslist_opt",  "select",      
-  "column",        "columnid",      "type",          "carglist",    
-  "id",            "ids",           "typetoken",     "typename",    
-  "signed",        "plus_num",      "minus_num",     "carg",        
+  "create_table",  "create_table_args",  "createkw",      "temp",        
+  "ifnotexists",   "dbnm",          "columnlist",    "conslist_opt",
+  "select",        "column",        "columnid",      "type",        
+  "carglist",      "id",            "ids",           "typetoken",   
+  "typename",      "signed",        "plus_num",      "minus_num",   
   "ccons",         "term",          "expr",          "onconf",      
   "sortorder",     "autoinc",       "idxlist_opt",   "refargs",     
   "defer_subclause",  "refarg",        "refact",        "init_deferred_pred_opt",
-  "conslist",      "tcons",         "idxlist",       "defer_subclause_opt",
-  "orconf",        "resolvetype",   "raisetype",     "ifexists",    
-  "fullname",      "oneselect",     "multiselect_op",  "distinct",    
-  "selcollist",    "from",          "where_opt",     "groupby_opt", 
-  "having_opt",    "orderby_opt",   "limit_opt",     "sclp",        
-  "as",            "seltablist",    "stl_prefix",    "joinop",      
-  "indexed_opt",   "on_opt",        "using_opt",     "joinop2",     
-  "inscollist",    "sortlist",      "sortitem",      "nexprlist",   
-  "setlist",       "insert_cmd",    "inscollist_opt",  "itemlist",    
-  "exprlist",      "likeop",        "escape",        "between_op",  
-  "in_op",         "case_operand",  "case_exprlist",  "case_else",   
-  "uniqueflag",    "collate",       "nmnum",         "plus_opt",    
-  "number",        "trigger_decl",  "trigger_cmd_list",  "trigger_time",
-  "trigger_event",  "foreach_clause",  "when_clause",   "trigger_cmd", 
+  "conslist",      "tconscomma",    "tcons",         "idxlist",     
+  "defer_subclause_opt",  "orconf",        "resolvetype",   "raisetype",   
+  "ifexists",      "fullname",      "oneselect",     "multiselect_op",
+  "distinct",      "selcollist",    "from",          "where_opt",   
+  "groupby_opt",   "having_opt",    "orderby_opt",   "limit_opt",   
+  "sclp",          "as",            "seltablist",    "stl_prefix",  
+  "joinop",        "indexed_opt",   "on_opt",        "using_opt",   
+  "joinop2",       "inscollist",    "sortlist",      "nexprlist",   
+  "setlist",       "insert_cmd",    "inscollist_opt",  "valuelist",   
+  "exprlist",      "likeop",        "between_op",    "in_op",       
+  "case_operand",  "case_exprlist",  "case_else",     "uniqueflag",  
+  "collate",       "nmnum",         "number",        "trigger_decl",
+  "trigger_cmd_list",  "trigger_time",  "trigger_event",  "foreach_clause",
+  "when_clause",   "trigger_cmd",   "trnm",          "tridxby",     
   "database_kw_opt",  "key_opt",       "add_column_fullname",  "kwcolumn_opt",
   "create_vtab",   "vtabarglist",   "vtabarg",       "vtabargtoken",
   "lp",            "anylist",     
@@ -83822,299 +107972,307 @@ static const char *const yyRuleName[] = {
  /*  23 */ "cmd ::= RELEASE savepoint_opt nm",
  /*  24 */ "cmd ::= ROLLBACK trans_opt TO savepoint_opt nm",
  /*  25 */ "cmd ::= create_table create_table_args",
- /*  26 */ "create_table ::= CREATE temp TABLE ifnotexists nm dbnm",
- /*  27 */ "ifnotexists ::=",
- /*  28 */ "ifnotexists ::= IF NOT EXISTS",
- /*  29 */ "temp ::= TEMP",
- /*  30 */ "temp ::=",
- /*  31 */ "create_table_args ::= LP columnlist conslist_opt RP",
- /*  32 */ "create_table_args ::= AS select",
- /*  33 */ "columnlist ::= columnlist COMMA column",
- /*  34 */ "columnlist ::= column",
- /*  35 */ "column ::= columnid type carglist",
- /*  36 */ "columnid ::= nm",
- /*  37 */ "id ::= ID",
- /*  38 */ "ids ::= ID|STRING",
- /*  39 */ "nm ::= ID",
- /*  40 */ "nm ::= STRING",
- /*  41 */ "nm ::= JOIN_KW",
- /*  42 */ "type ::=",
- /*  43 */ "type ::= typetoken",
- /*  44 */ "typetoken ::= typename",
- /*  45 */ "typetoken ::= typename LP signed RP",
- /*  46 */ "typetoken ::= typename LP signed COMMA signed RP",
- /*  47 */ "typename ::= ids",
- /*  48 */ "typename ::= typename ids",
- /*  49 */ "signed ::= plus_num",
- /*  50 */ "signed ::= minus_num",
- /*  51 */ "carglist ::= carglist carg",
- /*  52 */ "carglist ::=",
- /*  53 */ "carg ::= CONSTRAINT nm ccons",
- /*  54 */ "carg ::= ccons",
- /*  55 */ "ccons ::= DEFAULT term",
- /*  56 */ "ccons ::= DEFAULT LP expr RP",
- /*  57 */ "ccons ::= DEFAULT PLUS term",
- /*  58 */ "ccons ::= DEFAULT MINUS term",
- /*  59 */ "ccons ::= DEFAULT id",
- /*  60 */ "ccons ::= NULL onconf",
- /*  61 */ "ccons ::= NOT NULL onconf",
- /*  62 */ "ccons ::= PRIMARY KEY sortorder onconf autoinc",
- /*  63 */ "ccons ::= UNIQUE onconf",
- /*  64 */ "ccons ::= CHECK LP expr RP",
- /*  65 */ "ccons ::= REFERENCES nm idxlist_opt refargs",
- /*  66 */ "ccons ::= defer_subclause",
- /*  67 */ "ccons ::= COLLATE ids",
- /*  68 */ "autoinc ::=",
- /*  69 */ "autoinc ::= AUTOINCR",
- /*  70 */ "refargs ::=",
- /*  71 */ "refargs ::= refargs refarg",
- /*  72 */ "refarg ::= MATCH nm",
- /*  73 */ "refarg ::= ON DELETE refact",
- /*  74 */ "refarg ::= ON UPDATE refact",
- /*  75 */ "refarg ::= ON INSERT refact",
- /*  76 */ "refact ::= SET NULL",
- /*  77 */ "refact ::= SET DEFAULT",
- /*  78 */ "refact ::= CASCADE",
- /*  79 */ "refact ::= RESTRICT",
- /*  80 */ "defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt",
- /*  81 */ "defer_subclause ::= DEFERRABLE init_deferred_pred_opt",
- /*  82 */ "init_deferred_pred_opt ::=",
- /*  83 */ "init_deferred_pred_opt ::= INITIALLY DEFERRED",
- /*  84 */ "init_deferred_pred_opt ::= INITIALLY IMMEDIATE",
- /*  85 */ "conslist_opt ::=",
- /*  86 */ "conslist_opt ::= COMMA conslist",
- /*  87 */ "conslist ::= conslist COMMA tcons",
- /*  88 */ "conslist ::= conslist tcons",
- /*  89 */ "conslist ::= tcons",
- /*  90 */ "tcons ::= CONSTRAINT nm",
- /*  91 */ "tcons ::= PRIMARY KEY LP idxlist autoinc RP onconf",
- /*  92 */ "tcons ::= UNIQUE LP idxlist RP onconf",
- /*  93 */ "tcons ::= CHECK LP expr RP onconf",
- /*  94 */ "tcons ::= FOREIGN KEY LP idxlist RP REFERENCES nm idxlist_opt refargs defer_subclause_opt",
- /*  95 */ "defer_subclause_opt ::=",
- /*  96 */ "defer_subclause_opt ::= defer_subclause",
- /*  97 */ "onconf ::=",
- /*  98 */ "onconf ::= ON CONFLICT resolvetype",
- /*  99 */ "orconf ::=",
- /* 100 */ "orconf ::= OR resolvetype",
- /* 101 */ "resolvetype ::= raisetype",
- /* 102 */ "resolvetype ::= IGNORE",
- /* 103 */ "resolvetype ::= REPLACE",
- /* 104 */ "cmd ::= DROP TABLE ifexists fullname",
- /* 105 */ "ifexists ::= IF EXISTS",
- /* 106 */ "ifexists ::=",
- /* 107 */ "cmd ::= CREATE temp VIEW ifnotexists nm dbnm AS select",
- /* 108 */ "cmd ::= DROP VIEW ifexists fullname",
- /* 109 */ "cmd ::= select",
- /* 110 */ "select ::= oneselect",
- /* 111 */ "select ::= select multiselect_op oneselect",
- /* 112 */ "multiselect_op ::= UNION",
- /* 113 */ "multiselect_op ::= UNION ALL",
- /* 114 */ "multiselect_op ::= EXCEPT|INTERSECT",
- /* 115 */ "oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt",
- /* 116 */ "distinct ::= DISTINCT",
- /* 117 */ "distinct ::= ALL",
- /* 118 */ "distinct ::=",
- /* 119 */ "sclp ::= selcollist COMMA",
- /* 120 */ "sclp ::=",
- /* 121 */ "selcollist ::= sclp expr as",
- /* 122 */ "selcollist ::= sclp STAR",
- /* 123 */ "selcollist ::= sclp nm DOT STAR",
- /* 124 */ "as ::= AS nm",
- /* 125 */ "as ::= ids",
- /* 126 */ "as ::=",
- /* 127 */ "from ::=",
- /* 128 */ "from ::= FROM seltablist",
- /* 129 */ "stl_prefix ::= seltablist joinop",
- /* 130 */ "stl_prefix ::=",
- /* 131 */ "seltablist ::= stl_prefix nm dbnm as indexed_opt on_opt using_opt",
- /* 132 */ "seltablist ::= stl_prefix LP select RP as on_opt using_opt",
- /* 133 */ "seltablist ::= stl_prefix LP seltablist RP as on_opt using_opt",
- /* 134 */ "dbnm ::=",
- /* 135 */ "dbnm ::= DOT nm",
- /* 136 */ "fullname ::= nm dbnm",
- /* 137 */ "joinop ::= COMMA|JOIN",
- /* 138 */ "joinop ::= JOIN_KW JOIN",
- /* 139 */ "joinop ::= JOIN_KW nm JOIN",
- /* 140 */ "joinop ::= JOIN_KW nm nm JOIN",
- /* 141 */ "on_opt ::= ON expr",
- /* 142 */ "on_opt ::=",
- /* 143 */ "indexed_opt ::=",
- /* 144 */ "indexed_opt ::= INDEXED BY nm",
- /* 145 */ "indexed_opt ::= NOT INDEXED",
- /* 146 */ "using_opt ::= USING LP inscollist RP",
- /* 147 */ "using_opt ::=",
- /* 148 */ "orderby_opt ::=",
- /* 149 */ "orderby_opt ::= ORDER BY sortlist",
- /* 150 */ "sortlist ::= sortlist COMMA sortitem sortorder",
- /* 151 */ "sortlist ::= sortitem sortorder",
- /* 152 */ "sortitem ::= expr",
- /* 153 */ "sortorder ::= ASC",
- /* 154 */ "sortorder ::= DESC",
- /* 155 */ "sortorder ::=",
- /* 156 */ "groupby_opt ::=",
- /* 157 */ "groupby_opt ::= GROUP BY nexprlist",
- /* 158 */ "having_opt ::=",
- /* 159 */ "having_opt ::= HAVING expr",
- /* 160 */ "limit_opt ::=",
- /* 161 */ "limit_opt ::= LIMIT expr",
- /* 162 */ "limit_opt ::= LIMIT expr OFFSET expr",
- /* 163 */ "limit_opt ::= LIMIT expr COMMA expr",
- /* 164 */ "cmd ::= DELETE FROM fullname indexed_opt where_opt",
- /* 165 */ "where_opt ::=",
- /* 166 */ "where_opt ::= WHERE expr",
- /* 167 */ "cmd ::= UPDATE orconf fullname indexed_opt SET setlist where_opt",
- /* 168 */ "setlist ::= setlist COMMA nm EQ expr",
- /* 169 */ "setlist ::= nm EQ expr",
- /* 170 */ "cmd ::= insert_cmd INTO fullname inscollist_opt VALUES LP itemlist RP",
- /* 171 */ "cmd ::= insert_cmd INTO fullname inscollist_opt select",
- /* 172 */ "cmd ::= insert_cmd INTO fullname inscollist_opt DEFAULT VALUES",
- /* 173 */ "insert_cmd ::= INSERT orconf",
- /* 174 */ "insert_cmd ::= REPLACE",
- /* 175 */ "itemlist ::= itemlist COMMA expr",
- /* 176 */ "itemlist ::= expr",
- /* 177 */ "inscollist_opt ::=",
- /* 178 */ "inscollist_opt ::= LP inscollist RP",
- /* 179 */ "inscollist ::= inscollist COMMA nm",
- /* 180 */ "inscollist ::= nm",
- /* 181 */ "expr ::= term",
- /* 182 */ "expr ::= LP expr RP",
- /* 183 */ "term ::= NULL",
- /* 184 */ "expr ::= ID",
- /* 185 */ "expr ::= JOIN_KW",
- /* 186 */ "expr ::= nm DOT nm",
- /* 187 */ "expr ::= nm DOT nm DOT nm",
- /* 188 */ "term ::= INTEGER|FLOAT|BLOB",
- /* 189 */ "term ::= STRING",
- /* 190 */ "expr ::= REGISTER",
- /* 191 */ "expr ::= VARIABLE",
- /* 192 */ "expr ::= expr COLLATE ids",
- /* 193 */ "expr ::= CAST LP expr AS typetoken RP",
- /* 194 */ "expr ::= ID LP distinct exprlist RP",
- /* 195 */ "expr ::= ID LP STAR RP",
- /* 196 */ "term ::= CTIME_KW",
- /* 197 */ "expr ::= expr AND expr",
- /* 198 */ "expr ::= expr OR expr",
- /* 199 */ "expr ::= expr LT|GT|GE|LE expr",
- /* 200 */ "expr ::= expr EQ|NE expr",
- /* 201 */ "expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr",
- /* 202 */ "expr ::= expr PLUS|MINUS expr",
- /* 203 */ "expr ::= expr STAR|SLASH|REM expr",
- /* 204 */ "expr ::= expr CONCAT expr",
- /* 205 */ "likeop ::= LIKE_KW",
- /* 206 */ "likeop ::= NOT LIKE_KW",
- /* 207 */ "likeop ::= MATCH",
- /* 208 */ "likeop ::= NOT MATCH",
- /* 209 */ "escape ::= ESCAPE expr",
- /* 210 */ "escape ::=",
- /* 211 */ "expr ::= expr likeop expr escape",
- /* 212 */ "expr ::= expr ISNULL|NOTNULL",
- /* 213 */ "expr ::= expr IS NULL",
+ /*  26 */ "create_table ::= createkw temp TABLE ifnotexists nm dbnm",
+ /*  27 */ "createkw ::= CREATE",
+ /*  28 */ "ifnotexists ::=",
+ /*  29 */ "ifnotexists ::= IF NOT EXISTS",
+ /*  30 */ "temp ::= TEMP",
+ /*  31 */ "temp ::=",
+ /*  32 */ "create_table_args ::= LP columnlist conslist_opt RP",
+ /*  33 */ "create_table_args ::= AS select",
+ /*  34 */ "columnlist ::= columnlist COMMA column",
+ /*  35 */ "columnlist ::= column",
+ /*  36 */ "column ::= columnid type carglist",
+ /*  37 */ "columnid ::= nm",
+ /*  38 */ "id ::= ID",
+ /*  39 */ "id ::= INDEXED",
+ /*  40 */ "ids ::= ID|STRING",
+ /*  41 */ "nm ::= id",
+ /*  42 */ "nm ::= STRING",
+ /*  43 */ "nm ::= JOIN_KW",
+ /*  44 */ "type ::=",
+ /*  45 */ "type ::= typetoken",
+ /*  46 */ "typetoken ::= typename",
+ /*  47 */ "typetoken ::= typename LP signed RP",
+ /*  48 */ "typetoken ::= typename LP signed COMMA signed RP",
+ /*  49 */ "typename ::= ids",
+ /*  50 */ "typename ::= typename ids",
+ /*  51 */ "signed ::= plus_num",
+ /*  52 */ "signed ::= minus_num",
+ /*  53 */ "carglist ::= carglist ccons",
+ /*  54 */ "carglist ::=",
+ /*  55 */ "ccons ::= CONSTRAINT nm",
+ /*  56 */ "ccons ::= DEFAULT term",
+ /*  57 */ "ccons ::= DEFAULT LP expr RP",
+ /*  58 */ "ccons ::= DEFAULT PLUS term",
+ /*  59 */ "ccons ::= DEFAULT MINUS term",
+ /*  60 */ "ccons ::= DEFAULT id",
+ /*  61 */ "ccons ::= NULL onconf",
+ /*  62 */ "ccons ::= NOT NULL onconf",
+ /*  63 */ "ccons ::= PRIMARY KEY sortorder onconf autoinc",
+ /*  64 */ "ccons ::= UNIQUE onconf",
+ /*  65 */ "ccons ::= CHECK LP expr RP",
+ /*  66 */ "ccons ::= REFERENCES nm idxlist_opt refargs",
+ /*  67 */ "ccons ::= defer_subclause",
+ /*  68 */ "ccons ::= COLLATE ids",
+ /*  69 */ "autoinc ::=",
+ /*  70 */ "autoinc ::= AUTOINCR",
+ /*  71 */ "refargs ::=",
+ /*  72 */ "refargs ::= refargs refarg",
+ /*  73 */ "refarg ::= MATCH nm",
+ /*  74 */ "refarg ::= ON INSERT refact",
+ /*  75 */ "refarg ::= ON DELETE refact",
+ /*  76 */ "refarg ::= ON UPDATE refact",
+ /*  77 */ "refact ::= SET NULL",
+ /*  78 */ "refact ::= SET DEFAULT",
+ /*  79 */ "refact ::= CASCADE",
+ /*  80 */ "refact ::= RESTRICT",
+ /*  81 */ "refact ::= NO ACTION",
+ /*  82 */ "defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt",
+ /*  83 */ "defer_subclause ::= DEFERRABLE init_deferred_pred_opt",
+ /*  84 */ "init_deferred_pred_opt ::=",
+ /*  85 */ "init_deferred_pred_opt ::= INITIALLY DEFERRED",
+ /*  86 */ "init_deferred_pred_opt ::= INITIALLY IMMEDIATE",
+ /*  87 */ "conslist_opt ::=",
+ /*  88 */ "conslist_opt ::= COMMA conslist",
+ /*  89 */ "conslist ::= conslist tconscomma tcons",
+ /*  90 */ "conslist ::= tcons",
+ /*  91 */ "tconscomma ::= COMMA",
+ /*  92 */ "tconscomma ::=",
+ /*  93 */ "tcons ::= CONSTRAINT nm",
+ /*  94 */ "tcons ::= PRIMARY KEY LP idxlist autoinc RP onconf",
+ /*  95 */ "tcons ::= UNIQUE LP idxlist RP onconf",
+ /*  96 */ "tcons ::= CHECK LP expr RP onconf",
+ /*  97 */ "tcons ::= FOREIGN KEY LP idxlist RP REFERENCES nm idxlist_opt refargs defer_subclause_opt",
+ /*  98 */ "defer_subclause_opt ::=",
+ /*  99 */ "defer_subclause_opt ::= defer_subclause",
+ /* 100 */ "onconf ::=",
+ /* 101 */ "onconf ::= ON CONFLICT resolvetype",
+ /* 102 */ "orconf ::=",
+ /* 103 */ "orconf ::= OR resolvetype",
+ /* 104 */ "resolvetype ::= raisetype",
+ /* 105 */ "resolvetype ::= IGNORE",
+ /* 106 */ "resolvetype ::= REPLACE",
+ /* 107 */ "cmd ::= DROP TABLE ifexists fullname",
+ /* 108 */ "ifexists ::= IF EXISTS",
+ /* 109 */ "ifexists ::=",
+ /* 110 */ "cmd ::= createkw temp VIEW ifnotexists nm dbnm AS select",
+ /* 111 */ "cmd ::= DROP VIEW ifexists fullname",
+ /* 112 */ "cmd ::= select",
+ /* 113 */ "select ::= oneselect",
+ /* 114 */ "select ::= select multiselect_op oneselect",
+ /* 115 */ "multiselect_op ::= UNION",
+ /* 116 */ "multiselect_op ::= UNION ALL",
+ /* 117 */ "multiselect_op ::= EXCEPT|INTERSECT",
+ /* 118 */ "oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt",
+ /* 119 */ "distinct ::= DISTINCT",
+ /* 120 */ "distinct ::= ALL",
+ /* 121 */ "distinct ::=",
+ /* 122 */ "sclp ::= selcollist COMMA",
+ /* 123 */ "sclp ::=",
+ /* 124 */ "selcollist ::= sclp expr as",
+ /* 125 */ "selcollist ::= sclp STAR",
+ /* 126 */ "selcollist ::= sclp nm DOT STAR",
+ /* 127 */ "as ::= AS nm",
+ /* 128 */ "as ::= ids",
+ /* 129 */ "as ::=",
+ /* 130 */ "from ::=",
+ /* 131 */ "from ::= FROM seltablist",
+ /* 132 */ "stl_prefix ::= seltablist joinop",
+ /* 133 */ "stl_prefix ::=",
+ /* 134 */ "seltablist ::= stl_prefix nm dbnm as indexed_opt on_opt using_opt",
+ /* 135 */ "seltablist ::= stl_prefix LP select RP as on_opt using_opt",
+ /* 136 */ "seltablist ::= stl_prefix LP seltablist RP as on_opt using_opt",
+ /* 137 */ "dbnm ::=",
+ /* 138 */ "dbnm ::= DOT nm",
+ /* 139 */ "fullname ::= nm dbnm",
+ /* 140 */ "joinop ::= COMMA|JOIN",
+ /* 141 */ "joinop ::= JOIN_KW JOIN",
+ /* 142 */ "joinop ::= JOIN_KW nm JOIN",
+ /* 143 */ "joinop ::= JOIN_KW nm nm JOIN",
+ /* 144 */ "on_opt ::= ON expr",
+ /* 145 */ "on_opt ::=",
+ /* 146 */ "indexed_opt ::=",
+ /* 147 */ "indexed_opt ::= INDEXED BY nm",
+ /* 148 */ "indexed_opt ::= NOT INDEXED",
+ /* 149 */ "using_opt ::= USING LP inscollist RP",
+ /* 150 */ "using_opt ::=",
+ /* 151 */ "orderby_opt ::=",
+ /* 152 */ "orderby_opt ::= ORDER BY sortlist",
+ /* 153 */ "sortlist ::= sortlist COMMA expr sortorder",
+ /* 154 */ "sortlist ::= expr sortorder",
+ /* 155 */ "sortorder ::= ASC",
+ /* 156 */ "sortorder ::= DESC",
+ /* 157 */ "sortorder ::=",
+ /* 158 */ "groupby_opt ::=",
+ /* 159 */ "groupby_opt ::= GROUP BY nexprlist",
+ /* 160 */ "having_opt ::=",
+ /* 161 */ "having_opt ::= HAVING expr",
+ /* 162 */ "limit_opt ::=",
+ /* 163 */ "limit_opt ::= LIMIT expr",
+ /* 164 */ "limit_opt ::= LIMIT expr OFFSET expr",
+ /* 165 */ "limit_opt ::= LIMIT expr COMMA expr",
+ /* 166 */ "cmd ::= DELETE FROM fullname indexed_opt where_opt",
+ /* 167 */ "where_opt ::=",
+ /* 168 */ "where_opt ::= WHERE expr",
+ /* 169 */ "cmd ::= UPDATE orconf fullname indexed_opt SET setlist where_opt",
+ /* 170 */ "setlist ::= setlist COMMA nm EQ expr",
+ /* 171 */ "setlist ::= nm EQ expr",
+ /* 172 */ "cmd ::= insert_cmd INTO fullname inscollist_opt valuelist",
+ /* 173 */ "cmd ::= insert_cmd INTO fullname inscollist_opt select",
+ /* 174 */ "cmd ::= insert_cmd INTO fullname inscollist_opt DEFAULT VALUES",
+ /* 175 */ "insert_cmd ::= INSERT orconf",
+ /* 176 */ "insert_cmd ::= REPLACE",
+ /* 177 */ "valuelist ::= VALUES LP nexprlist RP",
+ /* 178 */ "valuelist ::= valuelist COMMA LP exprlist RP",
+ /* 179 */ "inscollist_opt ::=",
+ /* 180 */ "inscollist_opt ::= LP inscollist RP",
+ /* 181 */ "inscollist ::= inscollist COMMA nm",
+ /* 182 */ "inscollist ::= nm",
+ /* 183 */ "expr ::= term",
+ /* 184 */ "expr ::= LP expr RP",
+ /* 185 */ "term ::= NULL",
+ /* 186 */ "expr ::= id",
+ /* 187 */ "expr ::= JOIN_KW",
+ /* 188 */ "expr ::= nm DOT nm",
+ /* 189 */ "expr ::= nm DOT nm DOT nm",
+ /* 190 */ "term ::= INTEGER|FLOAT|BLOB",
+ /* 191 */ "term ::= STRING",
+ /* 192 */ "expr ::= REGISTER",
+ /* 193 */ "expr ::= VARIABLE",
+ /* 194 */ "expr ::= expr COLLATE ids",
+ /* 195 */ "expr ::= CAST LP expr AS typetoken RP",
+ /* 196 */ "expr ::= ID LP distinct exprlist RP",
+ /* 197 */ "expr ::= ID LP STAR RP",
+ /* 198 */ "term ::= CTIME_KW",
+ /* 199 */ "expr ::= expr AND expr",
+ /* 200 */ "expr ::= expr OR expr",
+ /* 201 */ "expr ::= expr LT|GT|GE|LE expr",
+ /* 202 */ "expr ::= expr EQ|NE expr",
+ /* 203 */ "expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr",
+ /* 204 */ "expr ::= expr PLUS|MINUS expr",
+ /* 205 */ "expr ::= expr STAR|SLASH|REM expr",
+ /* 206 */ "expr ::= expr CONCAT expr",
+ /* 207 */ "likeop ::= LIKE_KW",
+ /* 208 */ "likeop ::= NOT LIKE_KW",
+ /* 209 */ "likeop ::= MATCH",
+ /* 210 */ "likeop ::= NOT MATCH",
+ /* 211 */ "expr ::= expr likeop expr",
+ /* 212 */ "expr ::= expr likeop expr ESCAPE expr",
+ /* 213 */ "expr ::= expr ISNULL|NOTNULL",
  /* 214 */ "expr ::= expr NOT NULL",
- /* 215 */ "expr ::= expr IS NOT NULL",
- /* 216 */ "expr ::= NOT expr",
- /* 217 */ "expr ::= BITNOT expr",
- /* 218 */ "expr ::= MINUS expr",
- /* 219 */ "expr ::= PLUS expr",
- /* 220 */ "between_op ::= BETWEEN",
- /* 221 */ "between_op ::= NOT BETWEEN",
- /* 222 */ "expr ::= expr between_op expr AND expr",
- /* 223 */ "in_op ::= IN",
- /* 224 */ "in_op ::= NOT IN",
- /* 225 */ "expr ::= expr in_op LP exprlist RP",
- /* 226 */ "expr ::= LP select RP",
- /* 227 */ "expr ::= expr in_op LP select RP",
- /* 228 */ "expr ::= expr in_op nm dbnm",
- /* 229 */ "expr ::= EXISTS LP select RP",
- /* 230 */ "expr ::= CASE case_operand case_exprlist case_else END",
- /* 231 */ "case_exprlist ::= case_exprlist WHEN expr THEN expr",
- /* 232 */ "case_exprlist ::= WHEN expr THEN expr",
- /* 233 */ "case_else ::= ELSE expr",
- /* 234 */ "case_else ::=",
- /* 235 */ "case_operand ::= expr",
- /* 236 */ "case_operand ::=",
- /* 237 */ "exprlist ::= nexprlist",
- /* 238 */ "exprlist ::=",
- /* 239 */ "nexprlist ::= nexprlist COMMA expr",
- /* 240 */ "nexprlist ::= expr",
- /* 241 */ "cmd ::= CREATE uniqueflag INDEX ifnotexists nm dbnm ON nm LP idxlist RP",
- /* 242 */ "uniqueflag ::= UNIQUE",
- /* 243 */ "uniqueflag ::=",
- /* 244 */ "idxlist_opt ::=",
- /* 245 */ "idxlist_opt ::= LP idxlist RP",
- /* 246 */ "idxlist ::= idxlist COMMA nm collate sortorder",
- /* 247 */ "idxlist ::= nm collate sortorder",
- /* 248 */ "collate ::=",
- /* 249 */ "collate ::= COLLATE ids",
- /* 250 */ "cmd ::= DROP INDEX ifexists fullname",
- /* 251 */ "cmd ::= VACUUM",
- /* 252 */ "cmd ::= VACUUM nm",
- /* 253 */ "cmd ::= PRAGMA nm dbnm EQ nmnum",
- /* 254 */ "cmd ::= PRAGMA nm dbnm EQ ON",
- /* 255 */ "cmd ::= PRAGMA nm dbnm EQ DELETE",
- /* 256 */ "cmd ::= PRAGMA nm dbnm EQ minus_num",
- /* 257 */ "cmd ::= PRAGMA nm dbnm LP nmnum RP",
- /* 258 */ "cmd ::= PRAGMA nm dbnm",
+ /* 215 */ "expr ::= expr IS expr",
+ /* 216 */ "expr ::= expr IS NOT expr",
+ /* 217 */ "expr ::= NOT expr",
+ /* 218 */ "expr ::= BITNOT expr",
+ /* 219 */ "expr ::= MINUS expr",
+ /* 220 */ "expr ::= PLUS expr",
+ /* 221 */ "between_op ::= BETWEEN",
+ /* 222 */ "between_op ::= NOT BETWEEN",
+ /* 223 */ "expr ::= expr between_op expr AND expr",
+ /* 224 */ "in_op ::= IN",
+ /* 225 */ "in_op ::= NOT IN",
+ /* 226 */ "expr ::= expr in_op LP exprlist RP",
+ /* 227 */ "expr ::= LP select RP",
+ /* 228 */ "expr ::= expr in_op LP select RP",
+ /* 229 */ "expr ::= expr in_op nm dbnm",
+ /* 230 */ "expr ::= EXISTS LP select RP",
+ /* 231 */ "expr ::= CASE case_operand case_exprlist case_else END",
+ /* 232 */ "case_exprlist ::= case_exprlist WHEN expr THEN expr",
+ /* 233 */ "case_exprlist ::= WHEN expr THEN expr",
+ /* 234 */ "case_else ::= ELSE expr",
+ /* 235 */ "case_else ::=",
+ /* 236 */ "case_operand ::= expr",
+ /* 237 */ "case_operand ::=",
+ /* 238 */ "exprlist ::= nexprlist",
+ /* 239 */ "exprlist ::=",
+ /* 240 */ "nexprlist ::= nexprlist COMMA expr",
+ /* 241 */ "nexprlist ::= expr",
+ /* 242 */ "cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP idxlist RP",
+ /* 243 */ "uniqueflag ::= UNIQUE",
+ /* 244 */ "uniqueflag ::=",
+ /* 245 */ "idxlist_opt ::=",
+ /* 246 */ "idxlist_opt ::= LP idxlist RP",
+ /* 247 */ "idxlist ::= idxlist COMMA nm collate sortorder",
+ /* 248 */ "idxlist ::= nm collate sortorder",
+ /* 249 */ "collate ::=",
+ /* 250 */ "collate ::= COLLATE ids",
+ /* 251 */ "cmd ::= DROP INDEX ifexists fullname",
+ /* 252 */ "cmd ::= VACUUM",
+ /* 253 */ "cmd ::= VACUUM nm",
+ /* 254 */ "cmd ::= PRAGMA nm dbnm",
+ /* 255 */ "cmd ::= PRAGMA nm dbnm EQ nmnum",
+ /* 256 */ "cmd ::= PRAGMA nm dbnm LP nmnum RP",
+ /* 257 */ "cmd ::= PRAGMA nm dbnm EQ minus_num",
+ /* 258 */ "cmd ::= PRAGMA nm dbnm LP minus_num RP",
  /* 259 */ "nmnum ::= plus_num",
  /* 260 */ "nmnum ::= nm",
- /* 261 */ "plus_num ::= plus_opt number",
- /* 262 */ "minus_num ::= MINUS number",
- /* 263 */ "number ::= INTEGER|FLOAT",
- /* 264 */ "plus_opt ::= PLUS",
- /* 265 */ "plus_opt ::=",
- /* 266 */ "cmd ::= CREATE trigger_decl BEGIN trigger_cmd_list END",
- /* 267 */ "trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause",
- /* 268 */ "trigger_time ::= BEFORE",
- /* 269 */ "trigger_time ::= AFTER",
- /* 270 */ "trigger_time ::= INSTEAD OF",
- /* 271 */ "trigger_time ::=",
- /* 272 */ "trigger_event ::= DELETE|INSERT",
- /* 273 */ "trigger_event ::= UPDATE",
- /* 274 */ "trigger_event ::= UPDATE OF inscollist",
- /* 275 */ "foreach_clause ::=",
- /* 276 */ "foreach_clause ::= FOR EACH ROW",
- /* 277 */ "when_clause ::=",
- /* 278 */ "when_clause ::= WHEN expr",
- /* 279 */ "trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI",
- /* 280 */ "trigger_cmd_list ::= trigger_cmd SEMI",
- /* 281 */ "trigger_cmd ::= UPDATE orconf nm SET setlist where_opt",
- /* 282 */ "trigger_cmd ::= insert_cmd INTO nm inscollist_opt VALUES LP itemlist RP",
- /* 283 */ "trigger_cmd ::= insert_cmd INTO nm inscollist_opt select",
- /* 284 */ "trigger_cmd ::= DELETE FROM nm where_opt",
- /* 285 */ "trigger_cmd ::= select",
- /* 286 */ "expr ::= RAISE LP IGNORE RP",
- /* 287 */ "expr ::= RAISE LP raisetype COMMA nm RP",
- /* 288 */ "raisetype ::= ROLLBACK",
- /* 289 */ "raisetype ::= ABORT",
- /* 290 */ "raisetype ::= FAIL",
- /* 291 */ "cmd ::= DROP TRIGGER ifexists fullname",
- /* 292 */ "cmd ::= ATTACH database_kw_opt expr AS expr key_opt",
- /* 293 */ "cmd ::= DETACH database_kw_opt expr",
- /* 294 */ "key_opt ::=",
- /* 295 */ "key_opt ::= KEY expr",
- /* 296 */ "database_kw_opt ::= DATABASE",
- /* 297 */ "database_kw_opt ::=",
- /* 298 */ "cmd ::= REINDEX",
- /* 299 */ "cmd ::= REINDEX nm dbnm",
- /* 300 */ "cmd ::= ANALYZE",
- /* 301 */ "cmd ::= ANALYZE nm dbnm",
- /* 302 */ "cmd ::= ALTER TABLE fullname RENAME TO nm",
- /* 303 */ "cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column",
- /* 304 */ "add_column_fullname ::= fullname",
- /* 305 */ "kwcolumn_opt ::=",
- /* 306 */ "kwcolumn_opt ::= COLUMNKW",
- /* 307 */ "cmd ::= create_vtab",
- /* 308 */ "cmd ::= create_vtab LP vtabarglist RP",
- /* 309 */ "create_vtab ::= CREATE VIRTUAL TABLE nm dbnm USING nm",
- /* 310 */ "vtabarglist ::= vtabarg",
- /* 311 */ "vtabarglist ::= vtabarglist COMMA vtabarg",
- /* 312 */ "vtabarg ::=",
- /* 313 */ "vtabarg ::= vtabarg vtabargtoken",
- /* 314 */ "vtabargtoken ::= ANY",
- /* 315 */ "vtabargtoken ::= lp anylist RP",
- /* 316 */ "lp ::= LP",
- /* 317 */ "anylist ::=",
- /* 318 */ "anylist ::= anylist ANY",
+ /* 261 */ "nmnum ::= ON",
+ /* 262 */ "nmnum ::= DELETE",
+ /* 263 */ "nmnum ::= DEFAULT",
+ /* 264 */ "plus_num ::= PLUS number",
+ /* 265 */ "plus_num ::= number",
+ /* 266 */ "minus_num ::= MINUS number",
+ /* 267 */ "number ::= INTEGER|FLOAT",
+ /* 268 */ "cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END",
+ /* 269 */ "trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause",
+ /* 270 */ "trigger_time ::= BEFORE",
+ /* 271 */ "trigger_time ::= AFTER",
+ /* 272 */ "trigger_time ::= INSTEAD OF",
+ /* 273 */ "trigger_time ::=",
+ /* 274 */ "trigger_event ::= DELETE|INSERT",
+ /* 275 */ "trigger_event ::= UPDATE",
+ /* 276 */ "trigger_event ::= UPDATE OF inscollist",
+ /* 277 */ "foreach_clause ::=",
+ /* 278 */ "foreach_clause ::= FOR EACH ROW",
+ /* 279 */ "when_clause ::=",
+ /* 280 */ "when_clause ::= WHEN expr",
+ /* 281 */ "trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI",
+ /* 282 */ "trigger_cmd_list ::= trigger_cmd SEMI",
+ /* 283 */ "trnm ::= nm",
+ /* 284 */ "trnm ::= nm DOT nm",
+ /* 285 */ "tridxby ::=",
+ /* 286 */ "tridxby ::= INDEXED BY nm",
+ /* 287 */ "tridxby ::= NOT INDEXED",
+ /* 288 */ "trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist where_opt",
+ /* 289 */ "trigger_cmd ::= insert_cmd INTO trnm inscollist_opt valuelist",
+ /* 290 */ "trigger_cmd ::= insert_cmd INTO trnm inscollist_opt select",
+ /* 291 */ "trigger_cmd ::= DELETE FROM trnm tridxby where_opt",
+ /* 292 */ "trigger_cmd ::= select",
+ /* 293 */ "expr ::= RAISE LP IGNORE RP",
+ /* 294 */ "expr ::= RAISE LP raisetype COMMA nm RP",
+ /* 295 */ "raisetype ::= ROLLBACK",
+ /* 296 */ "raisetype ::= ABORT",
+ /* 297 */ "raisetype ::= FAIL",
+ /* 298 */ "cmd ::= DROP TRIGGER ifexists fullname",
+ /* 299 */ "cmd ::= ATTACH database_kw_opt expr AS expr key_opt",
+ /* 300 */ "cmd ::= DETACH database_kw_opt expr",
+ /* 301 */ "key_opt ::=",
+ /* 302 */ "key_opt ::= KEY expr",
+ /* 303 */ "database_kw_opt ::= DATABASE",
+ /* 304 */ "database_kw_opt ::=",
+ /* 305 */ "cmd ::= REINDEX",
+ /* 306 */ "cmd ::= REINDEX nm dbnm",
+ /* 307 */ "cmd ::= ANALYZE",
+ /* 308 */ "cmd ::= ANALYZE nm dbnm",
+ /* 309 */ "cmd ::= ALTER TABLE fullname RENAME TO nm",
+ /* 310 */ "cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column",
+ /* 311 */ "add_column_fullname ::= fullname",
+ /* 312 */ "kwcolumn_opt ::=",
+ /* 313 */ "kwcolumn_opt ::= COLUMNKW",
+ /* 314 */ "cmd ::= create_vtab",
+ /* 315 */ "cmd ::= create_vtab LP vtabarglist RP",
+ /* 316 */ "create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm",
+ /* 317 */ "vtabarglist ::= vtabarg",
+ /* 318 */ "vtabarglist ::= vtabarglist COMMA vtabarg",
+ /* 319 */ "vtabarg ::=",
+ /* 320 */ "vtabarg ::= vtabarg vtabargtoken",
+ /* 321 */ "vtabargtoken ::= ANY",
+ /* 322 */ "vtabargtoken ::= lp anylist RP",
+ /* 323 */ "lp ::= LP",
+ /* 324 */ "anylist ::=",
+ /* 325 */ "anylist ::= anylist LP anylist RP",
+ /* 326 */ "anylist ::= anylist ANY",
 };
 #endif /* NDEBUG */
 
@@ -84193,65 +108351,74 @@ static void yy_destructor(
     ** which appear on the RHS of the rule, but which are not used
     ** inside the C code.
     */
-    case 159: /* select */
-    case 193: /* oneselect */
+    case 160: /* select */
+    case 194: /* oneselect */
 {
 sqlite3SelectDelete(pParse->db, (yypminor->yy159));
 }
       break;
     case 173: /* term */
     case 174: /* expr */
-    case 198: /* where_opt */
-    case 200: /* having_opt */
-    case 209: /* on_opt */
-    case 214: /* sortitem */
-    case 222: /* escape */
-    case 225: /* case_operand */
-    case 227: /* case_else */
-    case 238: /* when_clause */
+{
+sqlite3ExprDelete(pParse->db, (yypminor->yy342).pExpr);
+}
+      break;
+    case 178: /* idxlist_opt */
+    case 187: /* idxlist */
+    case 197: /* selcollist */
+    case 200: /* groupby_opt */
+    case 202: /* orderby_opt */
+    case 204: /* sclp */
+    case 214: /* sortlist */
+    case 215: /* nexprlist */
+    case 216: /* setlist */
+    case 220: /* exprlist */
+    case 225: /* case_exprlist */
+{
+sqlite3ExprListDelete(pParse->db, (yypminor->yy442));
+}
+      break;
+    case 193: /* fullname */
+    case 198: /* from */
+    case 206: /* seltablist */
+    case 207: /* stl_prefix */
+{
+sqlite3SrcListDelete(pParse->db, (yypminor->yy347));
+}
+      break;
+    case 199: /* where_opt */
+    case 201: /* having_opt */
+    case 210: /* on_opt */
+    case 224: /* case_operand */
+    case 226: /* case_else */
+    case 236: /* when_clause */
     case 241: /* key_opt */
 {
 sqlite3ExprDelete(pParse->db, (yypminor->yy122));
 }
       break;
-    case 178: /* idxlist_opt */
-    case 186: /* idxlist */
-    case 196: /* selcollist */
-    case 199: /* groupby_opt */
-    case 201: /* orderby_opt */
-    case 203: /* sclp */
-    case 213: /* sortlist */
-    case 215: /* nexprlist */
-    case 216: /* setlist */
-    case 219: /* itemlist */
-    case 220: /* exprlist */
-    case 226: /* case_exprlist */
-{
-sqlite3ExprListDelete(pParse->db, (yypminor->yy442));
-}
-      break;
-    case 192: /* fullname */
-    case 197: /* from */
-    case 205: /* seltablist */
-    case 206: /* stl_prefix */
-{
-sqlite3SrcListDelete(pParse->db, (yypminor->yy347));
-}
-      break;
-    case 210: /* using_opt */
-    case 212: /* inscollist */
+    case 211: /* using_opt */
+    case 213: /* inscollist */
     case 218: /* inscollist_opt */
 {
 sqlite3IdListDelete(pParse->db, (yypminor->yy180));
 }
       break;
-    case 234: /* trigger_cmd_list */
-    case 239: /* trigger_cmd */
+    case 219: /* valuelist */
+{
+
+  sqlite3ExprListDelete(pParse->db, (yypminor->yy487).pList);
+  sqlite3SelectDelete(pParse->db, (yypminor->yy487).pSelect);
+
+}
+      break;
+    case 232: /* trigger_cmd_list */
+    case 237: /* trigger_cmd */
 {
 sqlite3DeleteTriggerStep(pParse->db, (yypminor->yy327));
 }
       break;
-    case 236: /* trigger_event */
+    case 234: /* trigger_event */
 {
 sqlite3IdListDelete(pParse->db, (yypminor->yy410).b);
 }
@@ -84272,7 +108439,9 @@ static int yy_pop_parser_stack(yyParser *pParser){
   YYCODETYPE yymajor;
   yyStackEntry *yytos = &pParser->yystack[pParser->yyidx];
 
-  if( pParser->yyidx<0 ) return 0;
+  /* There is no mechanism by which the parser stack can be popped below
+  ** empty in SQLite.  */
+  if( NEVER(pParser->yyidx<0) ) return 0;
 #ifndef NDEBUG
   if( yyTraceFILE && pParser->yyidx>=0 ){
     fprintf(yyTraceFILE,"%sPopping %s\n",
@@ -84303,7 +108472,9 @@ SQLITE_PRIVATE void sqlite3ParserFree(
   void (*freeProc)(void*)     /* Function used to reclaim memory */
 ){
   yyParser *pParser = (yyParser*)p;
-  if( pParser==0 ) return;
+  /* In SQLite, we never try to destroy a parser that was not successfully
+  ** created in the first place. */
+  if( NEVER(pParser==0) ) return;
   while( pParser->yyidx>=0 ) yy_pop_parser_stack(pParser);
 #if YYSTACKDEPTH<=0
   free(pParser->yystack);
@@ -84336,12 +108507,13 @@ static int yy_find_shift_action(
   int i;
   int stateno = pParser->yystack[pParser->yyidx].stateno;
  
-  if( stateno>YY_SHIFT_MAX || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
+  if( stateno>YY_SHIFT_COUNT
+   || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
     return yy_default[stateno];
   }
   assert( iLookAhead!=YYNOCODE );
   i += iLookAhead;
-  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
+  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
     if( iLookAhead>0 ){
 #ifdef YYFALLBACK
       YYCODETYPE iFallback;            /* Fallback token */
@@ -84359,7 +108531,15 @@ static int yy_find_shift_action(
 #ifdef YYWILDCARD
       {
         int j = i - iLookAhead + YYWILDCARD;
-        if( j>=0 && j<YY_SZ_ACTTAB && yy_lookahead[j]==YYWILDCARD ){
+        if( 
+#if YY_SHIFT_MIN+YYWILDCARD<0
+          j>=0 &&
+#endif
+#if YY_SHIFT_MAX+YYWILDCARD>=YY_ACTTAB_COUNT
+          j<YY_ACTTAB_COUNT &&
+#endif
+          yy_lookahead[j]==YYWILDCARD
+        ){
 #ifndef NDEBUG
           if( yyTraceFILE ){
             fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
@@ -84391,22 +108571,22 @@ static int yy_find_reduce_action(
 ){
   int i;
 #ifdef YYERRORSYMBOL
-  if( stateno>YY_REDUCE_MAX ){
+  if( stateno>YY_REDUCE_COUNT ){
     return yy_default[stateno];
   }
 #else
-  assert( stateno<=YY_REDUCE_MAX );
+  assert( stateno<=YY_REDUCE_COUNT );
 #endif
   i = yy_reduce_ofst[stateno];
   assert( i!=YY_REDUCE_USE_DFLT );
   assert( iLookAhead!=YYNOCODE );
   i += iLookAhead;
 #ifdef YYERRORSYMBOL
-  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
+  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
     return yy_default[stateno];
   }
 #else
-  assert( i>=0 && i<YY_SZ_ACTTAB );
+  assert( i>=0 && i<YY_ACTTAB_COUNT );
   assert( yy_lookahead[i]==iLookAhead );
 #endif
   return yy_action[i];
@@ -84429,7 +108609,6 @@ static void yyStackOverflow(yyParser *yypParser, YYMINORTYPE *yypMinor){
 
   UNUSED_PARAMETER(yypMinor); /* Silence some compiler warnings */
   sqlite3ErrorMsg(pParse, "parser stack overflow");
-  pParse->parseError = 1;
    sqlite3ParserARG_STORE; /* Suppress warning about unused %extra_argument var */
 }
 
@@ -84513,34 +108692,35 @@ static const struct {
   { 147, 5 },
   { 147, 2 },
   { 152, 6 },
-  { 155, 0 },
-  { 155, 3 },
   { 154, 1 },
-  { 154, 0 },
+  { 156, 0 },
+  { 156, 3 },
+  { 155, 1 },
+  { 155, 0 },
   { 153, 4 },
   { 153, 2 },
-  { 157, 3 },
-  { 157, 1 },
-  { 160, 3 },
-  { 161, 1 },
-  { 164, 1 },
-  { 165, 1 },
-  { 150, 1 },
-  { 150, 1 },
-  { 150, 1 },
-  { 162, 0 },
+  { 158, 3 },
+  { 158, 1 },
+  { 161, 3 },
   { 162, 1 },
+  { 165, 1 },
+  { 165, 1 },
   { 166, 1 },
-  { 166, 4 },
-  { 166, 6 },
-  { 167, 1 },
-  { 167, 2 },
-  { 168, 1 },
-  { 168, 1 },
-  { 163, 2 },
+  { 150, 1 },
+  { 150, 1 },
+  { 150, 1 },
   { 163, 0 },
-  { 171, 3 },
-  { 171, 1 },
+  { 163, 1 },
+  { 167, 1 },
+  { 167, 4 },
+  { 167, 6 },
+  { 168, 1 },
+  { 168, 2 },
+  { 169, 1 },
+  { 169, 1 },
+  { 164, 2 },
+  { 164, 0 },
+  { 172, 2 },
   { 172, 2 },
   { 172, 4 },
   { 172, 3 },
@@ -84566,107 +108746,108 @@ static const struct {
   { 182, 2 },
   { 182, 1 },
   { 182, 1 },
+  { 182, 2 },
   { 180, 3 },
   { 180, 2 },
   { 183, 0 },
   { 183, 2 },
   { 183, 2 },
-  { 158, 0 },
-  { 158, 2 },
+  { 159, 0 },
+  { 159, 2 },
   { 184, 3 },
-  { 184, 2 },
   { 184, 1 },
-  { 185, 2 },
-  { 185, 7 },
-  { 185, 5 },
-  { 185, 5 },
-  { 185, 10 },
-  { 187, 0 },
-  { 187, 1 },
+  { 185, 1 },
+  { 185, 0 },
+  { 186, 2 },
+  { 186, 7 },
+  { 186, 5 },
+  { 186, 5 },
+  { 186, 10 },
+  { 188, 0 },
+  { 188, 1 },
   { 175, 0 },
   { 175, 3 },
-  { 188, 0 },
-  { 188, 2 },
-  { 189, 1 },
-  { 189, 1 },
-  { 189, 1 },
+  { 189, 0 },
+  { 189, 2 },
+  { 190, 1 },
+  { 190, 1 },
+  { 190, 1 },
   { 147, 4 },
-  { 191, 2 },
-  { 191, 0 },
+  { 192, 2 },
+  { 192, 0 },
   { 147, 8 },
   { 147, 4 },
   { 147, 1 },
-  { 159, 1 },
-  { 159, 3 },
-  { 194, 1 },
-  { 194, 2 },
-  { 194, 1 },
-  { 193, 9 },
+  { 160, 1 },
+  { 160, 3 },
   { 195, 1 },
+  { 195, 2 },
   { 195, 1 },
-  { 195, 0 },
-  { 203, 2 },
-  { 203, 0 },
-  { 196, 3 },
-  { 196, 2 },
-  { 196, 4 },
+  { 194, 9 },
+  { 196, 1 },
+  { 196, 1 },
+  { 196, 0 },
   { 204, 2 },
-  { 204, 1 },
   { 204, 0 },
-  { 197, 0 },
+  { 197, 3 },
   { 197, 2 },
-  { 206, 2 },
-  { 206, 0 },
-  { 205, 7 },
-  { 205, 7 },
-  { 205, 7 },
-  { 156, 0 },
-  { 156, 2 },
-  { 192, 2 },
-  { 207, 1 },
+  { 197, 4 },
+  { 205, 2 },
+  { 205, 1 },
+  { 205, 0 },
+  { 198, 0 },
+  { 198, 2 },
   { 207, 2 },
-  { 207, 3 },
-  { 207, 4 },
-  { 209, 2 },
-  { 209, 0 },
-  { 208, 0 },
-  { 208, 3 },
+  { 207, 0 },
+  { 206, 7 },
+  { 206, 7 },
+  { 206, 7 },
+  { 157, 0 },
+  { 157, 2 },
+  { 193, 2 },
+  { 208, 1 },
   { 208, 2 },
-  { 210, 4 },
+  { 208, 3 },
+  { 208, 4 },
+  { 210, 2 },
   { 210, 0 },
-  { 201, 0 },
-  { 201, 3 },
-  { 213, 4 },
-  { 213, 2 },
-  { 214, 1 },
+  { 209, 0 },
+  { 209, 3 },
+  { 209, 2 },
+  { 211, 4 },
+  { 211, 0 },
+  { 202, 0 },
+  { 202, 3 },
+  { 214, 4 },
+  { 214, 2 },
   { 176, 1 },
   { 176, 1 },
   { 176, 0 },
-  { 199, 0 },
-  { 199, 3 },
   { 200, 0 },
-  { 200, 2 },
-  { 202, 0 },
-  { 202, 2 },
-  { 202, 4 },
-  { 202, 4 },
+  { 200, 3 },
+  { 201, 0 },
+  { 201, 2 },
+  { 203, 0 },
+  { 203, 2 },
+  { 203, 4 },
+  { 203, 4 },
   { 147, 5 },
-  { 198, 0 },
-  { 198, 2 },
+  { 199, 0 },
+  { 199, 2 },
   { 147, 7 },
   { 216, 5 },
   { 216, 3 },
-  { 147, 8 },
+  { 147, 5 },
   { 147, 5 },
   { 147, 6 },
   { 217, 2 },
   { 217, 1 },
-  { 219, 3 },
-  { 219, 1 },
+  { 219, 4 },
+  { 219, 5 },
   { 218, 0 },
   { 218, 3 },
-  { 212, 3 },
-  { 212, 1 },
+  { 213, 3 },
+  { 213, 1 },
   { 174, 1 },
   { 174, 3 },
   { 173, 1 },
@@ -84695,88 +108876,93 @@ static const struct {
   { 221, 2 },
   { 221, 1 },
   { 221, 2 },
+  { 174, 3 },
+  { 174, 5 },
+  { 174, 2 },
+  { 174, 3 },
+  { 174, 3 },
+  { 174, 4 },
+  { 174, 2 },
+  { 174, 2 },
+  { 174, 2 },
+  { 174, 2 },
+  { 222, 1 },
   { 222, 2 },
-  { 222, 0 },
-  { 174, 4 },
-  { 174, 2 },
-  { 174, 3 },
-  { 174, 3 },
-  { 174, 4 },
-  { 174, 2 },
-  { 174, 2 },
-  { 174, 2 },
-  { 174, 2 },
+  { 174, 5 },
   { 223, 1 },
   { 223, 2 },
   { 174, 5 },
-  { 224, 1 },
-  { 224, 2 },
-  { 174, 5 },
   { 174, 3 },
   { 174, 5 },
   { 174, 4 },
   { 174, 4 },
   { 174, 5 },
-  { 226, 5 },
-  { 226, 4 },
-  { 227, 2 },
-  { 227, 0 },
-  { 225, 1 },
-  { 225, 0 },
+  { 225, 5 },
+  { 225, 4 },
+  { 226, 2 },
+  { 226, 0 },
+  { 224, 1 },
+  { 224, 0 },
   { 220, 1 },
   { 220, 0 },
   { 215, 3 },
   { 215, 1 },
   { 147, 11 },
-  { 228, 1 },
-  { 228, 0 },
+  { 227, 1 },
+  { 227, 0 },
   { 178, 0 },
   { 178, 3 },
-  { 186, 5 },
-  { 186, 3 },
-  { 229, 0 },
-  { 229, 2 },
+  { 187, 5 },
+  { 187, 3 },
+  { 228, 0 },
+  { 228, 2 },
   { 147, 4 },
   { 147, 1 },
   { 147, 2 },
-  { 147, 5 },
-  { 147, 5 },
-  { 147, 5 },
+  { 147, 3 },
   { 147, 5 },
   { 147, 6 },
-  { 147, 3 },
-  { 230, 1 },
-  { 230, 1 },
-  { 169, 2 },
-  { 170, 2 },
-  { 232, 1 },
-  { 231, 1 },
-  { 231, 0 },
   { 147, 5 },
-  { 233, 11 },
-  { 235, 1 },
-  { 235, 1 },
-  { 235, 2 },
-  { 235, 0 },
-  { 236, 1 },
-  { 236, 1 },
-  { 236, 3 },
-  { 237, 0 },
-  { 237, 3 },
-  { 238, 0 },
-  { 238, 2 },
+  { 147, 6 },
+  { 229, 1 },
+  { 229, 1 },
+  { 229, 1 },
+  { 229, 1 },
+  { 229, 1 },
+  { 170, 2 },
+  { 170, 1 },
+  { 171, 2 },
+  { 230, 1 },
+  { 147, 5 },
+  { 231, 11 },
+  { 233, 1 },
+  { 233, 1 },
+  { 233, 2 },
+  { 233, 0 },
+  { 234, 1 },
+  { 234, 1 },
   { 234, 3 },
-  { 234, 2 },
-  { 239, 6 },
-  { 239, 8 },
-  { 239, 5 },
-  { 239, 4 },
-  { 239, 1 },
+  { 235, 0 },
+  { 235, 3 },
+  { 236, 0 },
+  { 236, 2 },
+  { 232, 3 },
+  { 232, 2 },
+  { 238, 1 },
+  { 238, 3 },
+  { 239, 0 },
+  { 239, 3 },
+  { 239, 2 },
+  { 237, 7 },
+  { 237, 5 },
+  { 237, 5 },
+  { 237, 5 },
+  { 237, 1 },
   { 174, 4 },
   { 174, 6 },
-  { 190, 1 },
-  { 190, 1 },
-  { 190, 1 },
+  { 191, 1 },
+  { 191, 1 },
+  { 191, 1 },
   { 147, 4 },
   { 147, 6 },
   { 147, 3 },
@@ -84795,7 +108981,7 @@ static const struct {
   { 243, 1 },
   { 147, 1 },
   { 147, 4 },
-  { 244, 7 },
+  { 244, 8 },
   { 245, 1 },
   { 245, 3 },
   { 246, 0 },
@@ -84804,6 +108990,7 @@ static const struct {
   { 247, 3 },
   { 248, 1 },
   { 249, 0 },
+  { 249, 4 },
   { 249, 2 },
 };
 
@@ -84859,46 +109046,6 @@ static void yy_reduce(
   **  #line <lineno> <thisfile>
   **     break;
   */
-      case 0: /* input ::= cmdlist */
-      case 1: /* cmdlist ::= cmdlist ecmd */
-      case 2: /* cmdlist ::= ecmd */
-      case 3: /* ecmd ::= SEMI */
-      case 4: /* ecmd ::= explain cmdx SEMI */
-      case 10: /* trans_opt ::= */
-      case 11: /* trans_opt ::= TRANSACTION */
-      case 12: /* trans_opt ::= TRANSACTION nm */
-      case 20: /* savepoint_opt ::= SAVEPOINT */
-      case 21: /* savepoint_opt ::= */
-      case 25: /* cmd ::= create_table create_table_args */
-      case 33: /* columnlist ::= columnlist COMMA column */
-      case 34: /* columnlist ::= column */
-      case 42: /* type ::= */
-      case 49: /* signed ::= plus_num */
-      case 50: /* signed ::= minus_num */
-      case 51: /* carglist ::= carglist carg */
-      case 52: /* carglist ::= */
-      case 53: /* carg ::= CONSTRAINT nm ccons */
-      case 54: /* carg ::= ccons */
-      case 60: /* ccons ::= NULL onconf */
-      case 87: /* conslist ::= conslist COMMA tcons */
-      case 88: /* conslist ::= conslist tcons */
-      case 89: /* conslist ::= tcons */
-      case 90: /* tcons ::= CONSTRAINT nm */
-      case 264: /* plus_opt ::= PLUS */
-      case 265: /* plus_opt ::= */
-      case 275: /* foreach_clause ::= */
-      case 276: /* foreach_clause ::= FOR EACH ROW */
-      case 296: /* database_kw_opt ::= DATABASE */
-      case 297: /* database_kw_opt ::= */
-      case 305: /* kwcolumn_opt ::= */
-      case 306: /* kwcolumn_opt ::= COLUMNKW */
-      case 310: /* vtabarglist ::= vtabarg */
-      case 311: /* vtabarglist ::= vtabarglist COMMA vtabarg */
-      case 313: /* vtabarg ::= vtabarg vtabargtoken */
-      case 317: /* anylist ::= */
-{
-}
-        break;
       case 5: /* explain ::= */
 { sqlite3BeginParse(pParse, 0); }
         break;
@@ -84918,14 +109065,14 @@ static void yy_reduce(
 {yygotominor.yy392 = TK_DEFERRED;}
         break;
       case 14: /* transtype ::= DEFERRED */
-      case 15: /* transtype ::= IMMEDIATE */
-      case 16: /* transtype ::= EXCLUSIVE */
-      case 112: /* multiselect_op ::= UNION */
-      case 114: /* multiselect_op ::= EXCEPT|INTERSECT */
+      case 15: /* transtype ::= IMMEDIATE */ yytestcase(yyruleno==15);
+      case 16: /* transtype ::= EXCLUSIVE */ yytestcase(yyruleno==16);
+      case 115: /* multiselect_op ::= UNION */ yytestcase(yyruleno==115);
+      case 117: /* multiselect_op ::= EXCEPT|INTERSECT */ yytestcase(yyruleno==117);
 {yygotominor.yy392 = yymsp[0].major;}
         break;
       case 17: /* cmd ::= COMMIT trans_opt */
-      case 18: /* cmd ::= END trans_opt */
+      case 18: /* cmd ::= END trans_opt */ yytestcase(yyruleno==18);
 {sqlite3CommitTransaction(pParse);}
         break;
       case 19: /* cmd ::= ROLLBACK trans_opt */
@@ -84946,232 +109093,261 @@ static void yy_reduce(
   sqlite3Savepoint(pParse, SAVEPOINT_ROLLBACK, &yymsp[0].minor.yy0);
 }
         break;
-      case 26: /* create_table ::= CREATE temp TABLE ifnotexists nm dbnm */
+      case 26: /* create_table ::= createkw temp TABLE ifnotexists nm dbnm */
 {
    sqlite3StartTable(pParse,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0,yymsp[-4].minor.yy392,0,0,yymsp[-2].minor.yy392);
 }
         break;
-      case 27: /* ifnotexists ::= */
-      case 30: /* temp ::= */
-      case 68: /* autoinc ::= */
-      case 82: /* init_deferred_pred_opt ::= */
-      case 84: /* init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
-      case 95: /* defer_subclause_opt ::= */
-      case 106: /* ifexists ::= */
-      case 117: /* distinct ::= ALL */
-      case 118: /* distinct ::= */
-      case 220: /* between_op ::= BETWEEN */
-      case 223: /* in_op ::= IN */
+      case 27: /* createkw ::= CREATE */
+{
+  pParse->db->lookaside.bEnabled = 0;
+  yygotominor.yy0 = yymsp[0].minor.yy0;
+}
+        break;
+      case 28: /* ifnotexists ::= */
+      case 31: /* temp ::= */ yytestcase(yyruleno==31);
+      case 69: /* autoinc ::= */ yytestcase(yyruleno==69);
+      case 82: /* defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */ yytestcase(yyruleno==82);
+      case 84: /* init_deferred_pred_opt ::= */ yytestcase(yyruleno==84);
+      case 86: /* init_deferred_pred_opt ::= INITIALLY IMMEDIATE */ yytestcase(yyruleno==86);
+      case 98: /* defer_subclause_opt ::= */ yytestcase(yyruleno==98);
+      case 109: /* ifexists ::= */ yytestcase(yyruleno==109);
+      case 120: /* distinct ::= ALL */ yytestcase(yyruleno==120);
+      case 121: /* distinct ::= */ yytestcase(yyruleno==121);
+      case 221: /* between_op ::= BETWEEN */ yytestcase(yyruleno==221);
+      case 224: /* in_op ::= IN */ yytestcase(yyruleno==224);
 {yygotominor.yy392 = 0;}
         break;
-      case 28: /* ifnotexists ::= IF NOT EXISTS */
-      case 29: /* temp ::= TEMP */
-      case 69: /* autoinc ::= AUTOINCR */
-      case 83: /* init_deferred_pred_opt ::= INITIALLY DEFERRED */
-      case 105: /* ifexists ::= IF EXISTS */
-      case 116: /* distinct ::= DISTINCT */
-      case 221: /* between_op ::= NOT BETWEEN */
-      case 224: /* in_op ::= NOT IN */
+      case 29: /* ifnotexists ::= IF NOT EXISTS */
+      case 30: /* temp ::= TEMP */ yytestcase(yyruleno==30);
+      case 70: /* autoinc ::= AUTOINCR */ yytestcase(yyruleno==70);
+      case 85: /* init_deferred_pred_opt ::= INITIALLY DEFERRED */ yytestcase(yyruleno==85);
+      case 108: /* ifexists ::= IF EXISTS */ yytestcase(yyruleno==108);
+      case 119: /* distinct ::= DISTINCT */ yytestcase(yyruleno==119);
+      case 222: /* between_op ::= NOT BETWEEN */ yytestcase(yyruleno==222);
+      case 225: /* in_op ::= NOT IN */ yytestcase(yyruleno==225);
 {yygotominor.yy392 = 1;}
         break;
-      case 31: /* create_table_args ::= LP columnlist conslist_opt RP */
+      case 32: /* create_table_args ::= LP columnlist conslist_opt RP */
 {
   sqlite3EndTable(pParse,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0,0);
 }
         break;
-      case 32: /* create_table_args ::= AS select */
+      case 33: /* create_table_args ::= AS select */
 {
   sqlite3EndTable(pParse,0,0,yymsp[0].minor.yy159);
   sqlite3SelectDelete(pParse->db, yymsp[0].minor.yy159);
 }
         break;
-      case 35: /* column ::= columnid type carglist */
+      case 36: /* column ::= columnid type carglist */
 {
   yygotominor.yy0.z = yymsp[-2].minor.yy0.z;
   yygotominor.yy0.n = (int)(pParse->sLastToken.z-yymsp[-2].minor.yy0.z) + pParse->sLastToken.n;
 }
         break;
-      case 36: /* columnid ::= nm */
+      case 37: /* columnid ::= nm */
 {
   sqlite3AddColumn(pParse,&yymsp[0].minor.yy0);
   yygotominor.yy0 = yymsp[0].minor.yy0;
+  pParse->constraintName.n = 0;
 }
         break;
-      case 37: /* id ::= ID */
-      case 38: /* ids ::= ID|STRING */
-      case 39: /* nm ::= ID */
-      case 40: /* nm ::= STRING */
-      case 41: /* nm ::= JOIN_KW */
-      case 44: /* typetoken ::= typename */
-      case 47: /* typename ::= ids */
-      case 124: /* as ::= AS nm */
-      case 125: /* as ::= ids */
-      case 135: /* dbnm ::= DOT nm */
-      case 144: /* indexed_opt ::= INDEXED BY nm */
-      case 249: /* collate ::= COLLATE ids */
-      case 259: /* nmnum ::= plus_num */
-      case 260: /* nmnum ::= nm */
-      case 261: /* plus_num ::= plus_opt number */
-      case 262: /* minus_num ::= MINUS number */
-      case 263: /* number ::= INTEGER|FLOAT */
+      case 38: /* id ::= ID */
+      case 39: /* id ::= INDEXED */ yytestcase(yyruleno==39);
+      case 40: /* ids ::= ID|STRING */ yytestcase(yyruleno==40);
+      case 41: /* nm ::= id */ yytestcase(yyruleno==41);
+      case 42: /* nm ::= STRING */ yytestcase(yyruleno==42);
+      case 43: /* nm ::= JOIN_KW */ yytestcase(yyruleno==43);
+      case 46: /* typetoken ::= typename */ yytestcase(yyruleno==46);
+      case 49: /* typename ::= ids */ yytestcase(yyruleno==49);
+      case 127: /* as ::= AS nm */ yytestcase(yyruleno==127);
+      case 128: /* as ::= ids */ yytestcase(yyruleno==128);
+      case 138: /* dbnm ::= DOT nm */ yytestcase(yyruleno==138);
+      case 147: /* indexed_opt ::= INDEXED BY nm */ yytestcase(yyruleno==147);
+      case 250: /* collate ::= COLLATE ids */ yytestcase(yyruleno==250);
+      case 259: /* nmnum ::= plus_num */ yytestcase(yyruleno==259);
+      case 260: /* nmnum ::= nm */ yytestcase(yyruleno==260);
+      case 261: /* nmnum ::= ON */ yytestcase(yyruleno==261);
+      case 262: /* nmnum ::= DELETE */ yytestcase(yyruleno==262);
+      case 263: /* nmnum ::= DEFAULT */ yytestcase(yyruleno==263);
+      case 264: /* plus_num ::= PLUS number */ yytestcase(yyruleno==264);
+      case 265: /* plus_num ::= number */ yytestcase(yyruleno==265);
+      case 266: /* minus_num ::= MINUS number */ yytestcase(yyruleno==266);
+      case 267: /* number ::= INTEGER|FLOAT */ yytestcase(yyruleno==267);
+      case 283: /* trnm ::= nm */ yytestcase(yyruleno==283);
 {yygotominor.yy0 = yymsp[0].minor.yy0;}
         break;
-      case 43: /* type ::= typetoken */
+      case 45: /* type ::= typetoken */
 {sqlite3AddColumnType(pParse,&yymsp[0].minor.yy0);}
         break;
-      case 45: /* typetoken ::= typename LP signed RP */
+      case 47: /* typetoken ::= typename LP signed RP */
 {
   yygotominor.yy0.z = yymsp[-3].minor.yy0.z;
   yygotominor.yy0.n = (int)(&yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-3].minor.yy0.z);
 }
         break;
-      case 46: /* typetoken ::= typename LP signed COMMA signed RP */
+      case 48: /* typetoken ::= typename LP signed COMMA signed RP */
 {
   yygotominor.yy0.z = yymsp[-5].minor.yy0.z;
   yygotominor.yy0.n = (int)(&yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-5].minor.yy0.z);
 }
         break;
-      case 48: /* typename ::= typename ids */
+      case 50: /* typename ::= typename ids */
 {yygotominor.yy0.z=yymsp[-1].minor.yy0.z; yygotominor.yy0.n=yymsp[0].minor.yy0.n+(int)(yymsp[0].minor.yy0.z-yymsp[-1].minor.yy0.z);}
         break;
-      case 55: /* ccons ::= DEFAULT term */
-      case 57: /* ccons ::= DEFAULT PLUS term */
-{sqlite3AddDefaultValue(pParse,yymsp[0].minor.yy122);}
+      case 55: /* ccons ::= CONSTRAINT nm */
+      case 93: /* tcons ::= CONSTRAINT nm */ yytestcase(yyruleno==93);
+{pParse->constraintName = yymsp[0].minor.yy0;}
         break;
-      case 56: /* ccons ::= DEFAULT LP expr RP */
-{sqlite3AddDefaultValue(pParse,yymsp[-1].minor.yy122);}
+      case 56: /* ccons ::= DEFAULT term */
+      case 58: /* ccons ::= DEFAULT PLUS term */ yytestcase(yyruleno==58);
+{sqlite3AddDefaultValue(pParse,&yymsp[0].minor.yy342);}
         break;
-      case 58: /* ccons ::= DEFAULT MINUS term */
+      case 57: /* ccons ::= DEFAULT LP expr RP */
+{sqlite3AddDefaultValue(pParse,&yymsp[-1].minor.yy342);}
+        break;
+      case 59: /* ccons ::= DEFAULT MINUS term */
 {
-  Expr *p = sqlite3PExpr(pParse, TK_UMINUS, yymsp[0].minor.yy122, 0, 0);
-  sqlite3ExprSpan(p,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy122->span);
-  sqlite3AddDefaultValue(pParse,p);
+  ExprSpan v;
+  v.pExpr = sqlite3PExpr(pParse, TK_UMINUS, yymsp[0].minor.yy342.pExpr, 0, 0);
+  v.zStart = yymsp[-1].minor.yy0.z;
+  v.zEnd = yymsp[0].minor.yy342.zEnd;
+  sqlite3AddDefaultValue(pParse,&v);
 }
         break;
-      case 59: /* ccons ::= DEFAULT id */
+      case 60: /* ccons ::= DEFAULT id */
 {
-  Expr *p = sqlite3PExpr(pParse, TK_STRING, 0, 0, &yymsp[0].minor.yy0);
-  sqlite3AddDefaultValue(pParse,p);
+  ExprSpan v;
+  spanExpr(&v, pParse, TK_STRING, &yymsp[0].minor.yy0);
+  sqlite3AddDefaultValue(pParse,&v);
 }
         break;
-      case 61: /* ccons ::= NOT NULL onconf */
+      case 62: /* ccons ::= NOT NULL onconf */
 {sqlite3AddNotNull(pParse, yymsp[0].minor.yy392);}
         break;
-      case 62: /* ccons ::= PRIMARY KEY sortorder onconf autoinc */
+      case 63: /* ccons ::= PRIMARY KEY sortorder onconf autoinc */
 {sqlite3AddPrimaryKey(pParse,0,yymsp[-1].minor.yy392,yymsp[0].minor.yy392,yymsp[-2].minor.yy392);}
         break;
-      case 63: /* ccons ::= UNIQUE onconf */
+      case 64: /* ccons ::= UNIQUE onconf */
 {sqlite3CreateIndex(pParse,0,0,0,0,yymsp[0].minor.yy392,0,0,0,0);}
         break;
-      case 64: /* ccons ::= CHECK LP expr RP */
-{sqlite3AddCheckConstraint(pParse,yymsp[-1].minor.yy122);}
+      case 65: /* ccons ::= CHECK LP expr RP */
+{sqlite3AddCheckConstraint(pParse,yymsp[-1].minor.yy342.pExpr);}
         break;
-      case 65: /* ccons ::= REFERENCES nm idxlist_opt refargs */
+      case 66: /* ccons ::= REFERENCES nm idxlist_opt refargs */
 {sqlite3CreateForeignKey(pParse,0,&yymsp[-2].minor.yy0,yymsp[-1].minor.yy442,yymsp[0].minor.yy392);}
         break;
-      case 66: /* ccons ::= defer_subclause */
+      case 67: /* ccons ::= defer_subclause */
 {sqlite3DeferForeignKey(pParse,yymsp[0].minor.yy392);}
         break;
-      case 67: /* ccons ::= COLLATE ids */
+      case 68: /* ccons ::= COLLATE ids */
 {sqlite3AddCollateType(pParse, &yymsp[0].minor.yy0);}
         break;
-      case 70: /* refargs ::= */
-{ yygotominor.yy392 = OE_Restrict * 0x010101; }
+      case 71: /* refargs ::= */
+{ yygotominor.yy392 = OE_None*0x0101; /* EV: R-19803-45884 */}
         break;
-      case 71: /* refargs ::= refargs refarg */
+      case 72: /* refargs ::= refargs refarg */
 { yygotominor.yy392 = (yymsp[-1].minor.yy392 & ~yymsp[0].minor.yy207.mask) | yymsp[0].minor.yy207.value; }
         break;
-      case 72: /* refarg ::= MATCH nm */
+      case 73: /* refarg ::= MATCH nm */
+      case 74: /* refarg ::= ON INSERT refact */ yytestcase(yyruleno==74);
 { yygotominor.yy207.value = 0;     yygotominor.yy207.mask = 0x000000; }
         break;
-      case 73: /* refarg ::= ON DELETE refact */
+      case 75: /* refarg ::= ON DELETE refact */
 { yygotominor.yy207.value = yymsp[0].minor.yy392;     yygotominor.yy207.mask = 0x0000ff; }
         break;
-      case 74: /* refarg ::= ON UPDATE refact */
+      case 76: /* refarg ::= ON UPDATE refact */
 { yygotominor.yy207.value = yymsp[0].minor.yy392<<8;  yygotominor.yy207.mask = 0x00ff00; }
         break;
-      case 75: /* refarg ::= ON INSERT refact */
-{ yygotominor.yy207.value = yymsp[0].minor.yy392<<16; yygotominor.yy207.mask = 0xff0000; }
+      case 77: /* refact ::= SET NULL */
+{ yygotominor.yy392 = OE_SetNull;  /* EV: R-33326-45252 */}
         break;
-      case 76: /* refact ::= SET NULL */
-{ yygotominor.yy392 = OE_SetNull; }
+      case 78: /* refact ::= SET DEFAULT */
+{ yygotominor.yy392 = OE_SetDflt;  /* EV: R-33326-45252 */}
         break;
-      case 77: /* refact ::= SET DEFAULT */
-{ yygotominor.yy392 = OE_SetDflt; }
+      case 79: /* refact ::= CASCADE */
+{ yygotominor.yy392 = OE_Cascade;  /* EV: R-33326-45252 */}
         break;
-      case 78: /* refact ::= CASCADE */
-{ yygotominor.yy392 = OE_Cascade; }
+      case 80: /* refact ::= RESTRICT */
+{ yygotominor.yy392 = OE_Restrict; /* EV: R-33326-45252 */}
         break;
-      case 79: /* refact ::= RESTRICT */
-{ yygotominor.yy392 = OE_Restrict; }
+      case 81: /* refact ::= NO ACTION */
+{ yygotominor.yy392 = OE_None;     /* EV: R-33326-45252 */}
         break;
-      case 80: /* defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
-      case 81: /* defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
-      case 96: /* defer_subclause_opt ::= defer_subclause */
-      case 98: /* onconf ::= ON CONFLICT resolvetype */
-      case 100: /* orconf ::= OR resolvetype */
-      case 101: /* resolvetype ::= raisetype */
-      case 173: /* insert_cmd ::= INSERT orconf */
+      case 83: /* defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+      case 99: /* defer_subclause_opt ::= defer_subclause */ yytestcase(yyruleno==99);
+      case 101: /* onconf ::= ON CONFLICT resolvetype */ yytestcase(yyruleno==101);
+      case 104: /* resolvetype ::= raisetype */ yytestcase(yyruleno==104);
 {yygotominor.yy392 = yymsp[0].minor.yy392;}
         break;
-      case 85: /* conslist_opt ::= */
+      case 87: /* conslist_opt ::= */
 {yygotominor.yy0.n = 0; yygotominor.yy0.z = 0;}
         break;
-      case 86: /* conslist_opt ::= COMMA conslist */
+      case 88: /* conslist_opt ::= COMMA conslist */
 {yygotominor.yy0 = yymsp[-1].minor.yy0;}
         break;
-      case 91: /* tcons ::= PRIMARY KEY LP idxlist autoinc RP onconf */
+      case 91: /* tconscomma ::= COMMA */
+{pParse->constraintName.n = 0;}
+        break;
+      case 94: /* tcons ::= PRIMARY KEY LP idxlist autoinc RP onconf */
 {sqlite3AddPrimaryKey(pParse,yymsp[-3].minor.yy442,yymsp[0].minor.yy392,yymsp[-2].minor.yy392,0);}
         break;
-      case 92: /* tcons ::= UNIQUE LP idxlist RP onconf */
+      case 95: /* tcons ::= UNIQUE LP idxlist RP onconf */
 {sqlite3CreateIndex(pParse,0,0,0,yymsp[-2].minor.yy442,yymsp[0].minor.yy392,0,0,0,0);}
         break;
-      case 93: /* tcons ::= CHECK LP expr RP onconf */
-{sqlite3AddCheckConstraint(pParse,yymsp[-2].minor.yy122);}
+      case 96: /* tcons ::= CHECK LP expr RP onconf */
+{sqlite3AddCheckConstraint(pParse,yymsp[-2].minor.yy342.pExpr);}
         break;
-      case 94: /* tcons ::= FOREIGN KEY LP idxlist RP REFERENCES nm idxlist_opt refargs defer_subclause_opt */
+      case 97: /* tcons ::= FOREIGN KEY LP idxlist RP REFERENCES nm idxlist_opt refargs defer_subclause_opt */
 {
     sqlite3CreateForeignKey(pParse, yymsp[-6].minor.yy442, &yymsp[-3].minor.yy0, yymsp[-2].minor.yy442, yymsp[-1].minor.yy392);
     sqlite3DeferForeignKey(pParse, yymsp[0].minor.yy392);
 }
         break;
-      case 97: /* onconf ::= */
-      case 99: /* orconf ::= */
+      case 100: /* onconf ::= */
 {yygotominor.yy392 = OE_Default;}
         break;
-      case 102: /* resolvetype ::= IGNORE */
+      case 102: /* orconf ::= */
+{yygotominor.yy258 = OE_Default;}
+        break;
+      case 103: /* orconf ::= OR resolvetype */
+{yygotominor.yy258 = (u8)yymsp[0].minor.yy392;}
+        break;
+      case 105: /* resolvetype ::= IGNORE */
 {yygotominor.yy392 = OE_Ignore;}
         break;
-      case 103: /* resolvetype ::= REPLACE */
-      case 174: /* insert_cmd ::= REPLACE */
+      case 106: /* resolvetype ::= REPLACE */
 {yygotominor.yy392 = OE_Replace;}
         break;
-      case 104: /* cmd ::= DROP TABLE ifexists fullname */
+      case 107: /* cmd ::= DROP TABLE ifexists fullname */
 {
   sqlite3DropTable(pParse, yymsp[0].minor.yy347, 0, yymsp[-1].minor.yy392);
 }
         break;
-      case 107: /* cmd ::= CREATE temp VIEW ifnotexists nm dbnm AS select */
+      case 110: /* cmd ::= createkw temp VIEW ifnotexists nm dbnm AS select */
 {
   sqlite3CreateView(pParse, &yymsp[-7].minor.yy0, &yymsp[-3].minor.yy0, &yymsp[-2].minor.yy0, yymsp[0].minor.yy159, yymsp[-6].minor.yy392, yymsp[-4].minor.yy392);
 }
         break;
-      case 108: /* cmd ::= DROP VIEW ifexists fullname */
+      case 111: /* cmd ::= DROP VIEW ifexists fullname */
 {
   sqlite3DropTable(pParse, yymsp[0].minor.yy347, 1, yymsp[-1].minor.yy392);
 }
         break;
-      case 109: /* cmd ::= select */
+      case 112: /* cmd ::= select */
 {
   SelectDest dest = {SRT_Output, 0, 0, 0, 0};
   sqlite3Select(pParse, yymsp[0].minor.yy159, &dest);
+  sqlite3ExplainBegin(pParse->pVdbe);
+  sqlite3ExplainSelect(pParse->pVdbe, yymsp[0].minor.yy159);
+  sqlite3ExplainFinish(pParse->pVdbe);
   sqlite3SelectDelete(pParse->db, yymsp[0].minor.yy159);
 }
         break;
-      case 110: /* select ::= oneselect */
+      case 113: /* select ::= oneselect */
 {yygotominor.yy159 = yymsp[0].minor.yy159;}
         break;
-      case 111: /* select ::= select multiselect_op oneselect */
+      case 114: /* select ::= select multiselect_op oneselect */
 {
   if( yymsp[0].minor.yy159 ){
     yymsp[0].minor.yy159->op = (u8)yymsp[-1].minor.yy392;
@@ -85182,77 +109358,79 @@ static void yy_reduce(
   yygotominor.yy159 = yymsp[0].minor.yy159;
 }
         break;
-      case 113: /* multiselect_op ::= UNION ALL */
+      case 116: /* multiselect_op ::= UNION ALL */
 {yygotominor.yy392 = TK_ALL;}
         break;
-      case 115: /* oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+      case 118: /* oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
 {
   yygotominor.yy159 = sqlite3SelectNew(pParse,yymsp[-6].minor.yy442,yymsp[-5].minor.yy347,yymsp[-4].minor.yy122,yymsp[-3].minor.yy442,yymsp[-2].minor.yy122,yymsp[-1].minor.yy442,yymsp[-7].minor.yy392,yymsp[0].minor.yy64.pLimit,yymsp[0].minor.yy64.pOffset);
 }
         break;
-      case 119: /* sclp ::= selcollist COMMA */
-      case 245: /* idxlist_opt ::= LP idxlist RP */
+      case 122: /* sclp ::= selcollist COMMA */
+      case 246: /* idxlist_opt ::= LP idxlist RP */ yytestcase(yyruleno==246);
 {yygotominor.yy442 = yymsp[-1].minor.yy442;}
         break;
-      case 120: /* sclp ::= */
-      case 148: /* orderby_opt ::= */
-      case 156: /* groupby_opt ::= */
-      case 238: /* exprlist ::= */
-      case 244: /* idxlist_opt ::= */
+      case 123: /* sclp ::= */
+      case 151: /* orderby_opt ::= */ yytestcase(yyruleno==151);
+      case 158: /* groupby_opt ::= */ yytestcase(yyruleno==158);
+      case 239: /* exprlist ::= */ yytestcase(yyruleno==239);
+      case 245: /* idxlist_opt ::= */ yytestcase(yyruleno==245);
 {yygotominor.yy442 = 0;}
         break;
-      case 121: /* selcollist ::= sclp expr as */
+      case 124: /* selcollist ::= sclp expr as */
 {
-   yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy442,yymsp[-1].minor.yy122,yymsp[0].minor.yy0.n?&yymsp[0].minor.yy0:0);
+   yygotominor.yy442 = sqlite3ExprListAppend(pParse, yymsp[-2].minor.yy442, yymsp[-1].minor.yy342.pExpr);
+   if( yymsp[0].minor.yy0.n>0 ) sqlite3ExprListSetName(pParse, yygotominor.yy442, &yymsp[0].minor.yy0, 1);
+   sqlite3ExprListSetSpan(pParse,yygotominor.yy442,&yymsp[-1].minor.yy342);
 }
         break;
-      case 122: /* selcollist ::= sclp STAR */
+      case 125: /* selcollist ::= sclp STAR */
 {
-  Expr *p = sqlite3PExpr(pParse, TK_ALL, 0, 0, 0);
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse, yymsp[-1].minor.yy442, p, 0);
+  Expr *p = sqlite3Expr(pParse->db, TK_ALL, 0);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse, yymsp[-1].minor.yy442, p);
 }
         break;
-      case 123: /* selcollist ::= sclp nm DOT STAR */
+      case 126: /* selcollist ::= sclp nm DOT STAR */
 {
   Expr *pRight = sqlite3PExpr(pParse, TK_ALL, 0, 0, &yymsp[0].minor.yy0);
   Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-2].minor.yy0);
   Expr *pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy442, pDot, 0);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy442, pDot);
 }
         break;
-      case 126: /* as ::= */
+      case 129: /* as ::= */
 {yygotominor.yy0.n = 0;}
         break;
-      case 127: /* from ::= */
+      case 130: /* from ::= */
 {yygotominor.yy347 = sqlite3DbMallocZero(pParse->db, sizeof(*yygotominor.yy347));}
         break;
-      case 128: /* from ::= FROM seltablist */
+      case 131: /* from ::= FROM seltablist */
 {
   yygotominor.yy347 = yymsp[0].minor.yy347;
   sqlite3SrcListShiftJoinType(yygotominor.yy347);
 }
         break;
-      case 129: /* stl_prefix ::= seltablist joinop */
+      case 132: /* stl_prefix ::= seltablist joinop */
 {
    yygotominor.yy347 = yymsp[-1].minor.yy347;
-   if( yygotominor.yy347 && yygotominor.yy347->nSrc>0 ) yygotominor.yy347->a[yygotominor.yy347->nSrc-1].jointype = (u8)yymsp[0].minor.yy392;
+   if( ALWAYS(yygotominor.yy347 && yygotominor.yy347->nSrc>0) ) yygotominor.yy347->a[yygotominor.yy347->nSrc-1].jointype = (u8)yymsp[0].minor.yy392;
 }
         break;
-      case 130: /* stl_prefix ::= */
+      case 133: /* stl_prefix ::= */
 {yygotominor.yy347 = 0;}
         break;
-      case 131: /* seltablist ::= stl_prefix nm dbnm as indexed_opt on_opt using_opt */
+      case 134: /* seltablist ::= stl_prefix nm dbnm as indexed_opt on_opt using_opt */
 {
   yygotominor.yy347 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-6].minor.yy347,&yymsp[-5].minor.yy0,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,0,yymsp[-1].minor.yy122,yymsp[0].minor.yy180);
   sqlite3SrcListIndexedBy(pParse, yygotominor.yy347, &yymsp[-2].minor.yy0);
 }
         break;
-      case 132: /* seltablist ::= stl_prefix LP select RP as on_opt using_opt */
+      case 135: /* seltablist ::= stl_prefix LP select RP as on_opt using_opt */
 {
     yygotominor.yy347 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-6].minor.yy347,0,0,&yymsp[-2].minor.yy0,yymsp[-4].minor.yy159,yymsp[-1].minor.yy122,yymsp[0].minor.yy180);
   }
         break;
-      case 133: /* seltablist ::= stl_prefix LP seltablist RP as on_opt using_opt */
+      case 136: /* seltablist ::= stl_prefix LP seltablist RP as on_opt using_opt */
 {
     if( yymsp[-6].minor.yy347==0 && yymsp[-2].minor.yy0.n==0 && yymsp[-1].minor.yy122==0 && yymsp[0].minor.yy180==0 ){
       yygotominor.yy347 = yymsp[-4].minor.yy347;
@@ -85264,452 +109442,525 @@ static void yy_reduce(
     }
   }
         break;
-      case 134: /* dbnm ::= */
-      case 143: /* indexed_opt ::= */
+      case 137: /* dbnm ::= */
+      case 146: /* indexed_opt ::= */ yytestcase(yyruleno==146);
 {yygotominor.yy0.z=0; yygotominor.yy0.n=0;}
         break;
-      case 136: /* fullname ::= nm dbnm */
+      case 139: /* fullname ::= nm dbnm */
 {yygotominor.yy347 = sqlite3SrcListAppend(pParse->db,0,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0);}
         break;
-      case 137: /* joinop ::= COMMA|JOIN */
+      case 140: /* joinop ::= COMMA|JOIN */
 { yygotominor.yy392 = JT_INNER; }
         break;
-      case 138: /* joinop ::= JOIN_KW JOIN */
+      case 141: /* joinop ::= JOIN_KW JOIN */
 { yygotominor.yy392 = sqlite3JoinType(pParse,&yymsp[-1].minor.yy0,0,0); }
         break;
-      case 139: /* joinop ::= JOIN_KW nm JOIN */
+      case 142: /* joinop ::= JOIN_KW nm JOIN */
 { yygotominor.yy392 = sqlite3JoinType(pParse,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0,0); }
         break;
-      case 140: /* joinop ::= JOIN_KW nm nm JOIN */
+      case 143: /* joinop ::= JOIN_KW nm nm JOIN */
 { yygotominor.yy392 = sqlite3JoinType(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0); }
         break;
-      case 141: /* on_opt ::= ON expr */
-      case 152: /* sortitem ::= expr */
-      case 159: /* having_opt ::= HAVING expr */
-      case 166: /* where_opt ::= WHERE expr */
-      case 181: /* expr ::= term */
-      case 209: /* escape ::= ESCAPE expr */
-      case 233: /* case_else ::= ELSE expr */
-      case 235: /* case_operand ::= expr */
-{yygotominor.yy122 = yymsp[0].minor.yy122;}
+      case 144: /* on_opt ::= ON expr */
+      case 161: /* having_opt ::= HAVING expr */ yytestcase(yyruleno==161);
+      case 168: /* where_opt ::= WHERE expr */ yytestcase(yyruleno==168);
+      case 234: /* case_else ::= ELSE expr */ yytestcase(yyruleno==234);
+      case 236: /* case_operand ::= expr */ yytestcase(yyruleno==236);
+{yygotominor.yy122 = yymsp[0].minor.yy342.pExpr;}
         break;
-      case 142: /* on_opt ::= */
-      case 158: /* having_opt ::= */
-      case 165: /* where_opt ::= */
-      case 210: /* escape ::= */
-      case 234: /* case_else ::= */
-      case 236: /* case_operand ::= */
+      case 145: /* on_opt ::= */
+      case 160: /* having_opt ::= */ yytestcase(yyruleno==160);
+      case 167: /* where_opt ::= */ yytestcase(yyruleno==167);
+      case 235: /* case_else ::= */ yytestcase(yyruleno==235);
+      case 237: /* case_operand ::= */ yytestcase(yyruleno==237);
 {yygotominor.yy122 = 0;}
         break;
-      case 145: /* indexed_opt ::= NOT INDEXED */
+      case 148: /* indexed_opt ::= NOT INDEXED */
 {yygotominor.yy0.z=0; yygotominor.yy0.n=1;}
         break;
-      case 146: /* using_opt ::= USING LP inscollist RP */
-      case 178: /* inscollist_opt ::= LP inscollist RP */
+      case 149: /* using_opt ::= USING LP inscollist RP */
+      case 180: /* inscollist_opt ::= LP inscollist RP */ yytestcase(yyruleno==180);
 {yygotominor.yy180 = yymsp[-1].minor.yy180;}
         break;
-      case 147: /* using_opt ::= */
-      case 177: /* inscollist_opt ::= */
+      case 150: /* using_opt ::= */
+      case 179: /* inscollist_opt ::= */ yytestcase(yyruleno==179);
 {yygotominor.yy180 = 0;}
         break;
-      case 149: /* orderby_opt ::= ORDER BY sortlist */
-      case 157: /* groupby_opt ::= GROUP BY nexprlist */
-      case 237: /* exprlist ::= nexprlist */
+      case 152: /* orderby_opt ::= ORDER BY sortlist */
+      case 159: /* groupby_opt ::= GROUP BY nexprlist */ yytestcase(yyruleno==159);
+      case 238: /* exprlist ::= nexprlist */ yytestcase(yyruleno==238);
 {yygotominor.yy442 = yymsp[0].minor.yy442;}
         break;
-      case 150: /* sortlist ::= sortlist COMMA sortitem sortorder */
+      case 153: /* sortlist ::= sortlist COMMA expr sortorder */
 {
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy442,yymsp[-1].minor.yy122,0);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy442,yymsp[-1].minor.yy342.pExpr);
   if( yygotominor.yy442 ) yygotominor.yy442->a[yygotominor.yy442->nExpr-1].sortOrder = (u8)yymsp[0].minor.yy392;
 }
         break;
-      case 151: /* sortlist ::= sortitem sortorder */
+      case 154: /* sortlist ::= expr sortorder */
 {
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,0,yymsp[-1].minor.yy122,0);
-  if( yygotominor.yy442 && yygotominor.yy442->a ) yygotominor.yy442->a[0].sortOrder = (u8)yymsp[0].minor.yy392;
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,0,yymsp[-1].minor.yy342.pExpr);
+  if( yygotominor.yy442 && ALWAYS(yygotominor.yy442->a) ) yygotominor.yy442->a[0].sortOrder = (u8)yymsp[0].minor.yy392;
 }
         break;
-      case 153: /* sortorder ::= ASC */
-      case 155: /* sortorder ::= */
+      case 155: /* sortorder ::= ASC */
+      case 157: /* sortorder ::= */ yytestcase(yyruleno==157);
 {yygotominor.yy392 = SQLITE_SO_ASC;}
         break;
-      case 154: /* sortorder ::= DESC */
+      case 156: /* sortorder ::= DESC */
 {yygotominor.yy392 = SQLITE_SO_DESC;}
         break;
-      case 160: /* limit_opt ::= */
+      case 162: /* limit_opt ::= */
 {yygotominor.yy64.pLimit = 0; yygotominor.yy64.pOffset = 0;}
         break;
-      case 161: /* limit_opt ::= LIMIT expr */
-{yygotominor.yy64.pLimit = yymsp[0].minor.yy122; yygotominor.yy64.pOffset = 0;}
+      case 163: /* limit_opt ::= LIMIT expr */
+{yygotominor.yy64.pLimit = yymsp[0].minor.yy342.pExpr; yygotominor.yy64.pOffset = 0;}
         break;
-      case 162: /* limit_opt ::= LIMIT expr OFFSET expr */
-{yygotominor.yy64.pLimit = yymsp[-2].minor.yy122; yygotominor.yy64.pOffset = yymsp[0].minor.yy122;}
+      case 164: /* limit_opt ::= LIMIT expr OFFSET expr */
+{yygotominor.yy64.pLimit = yymsp[-2].minor.yy342.pExpr; yygotominor.yy64.pOffset = yymsp[0].minor.yy342.pExpr;}
         break;
-      case 163: /* limit_opt ::= LIMIT expr COMMA expr */
-{yygotominor.yy64.pOffset = yymsp[-2].minor.yy122; yygotominor.yy64.pLimit = yymsp[0].minor.yy122;}
+      case 165: /* limit_opt ::= LIMIT expr COMMA expr */
+{yygotominor.yy64.pOffset = yymsp[-2].minor.yy342.pExpr; yygotominor.yy64.pLimit = yymsp[0].minor.yy342.pExpr;}
         break;
-      case 164: /* cmd ::= DELETE FROM fullname indexed_opt where_opt */
+      case 166: /* cmd ::= DELETE FROM fullname indexed_opt where_opt */
 {
   sqlite3SrcListIndexedBy(pParse, yymsp[-2].minor.yy347, &yymsp[-1].minor.yy0);
   sqlite3DeleteFrom(pParse,yymsp[-2].minor.yy347,yymsp[0].minor.yy122);
 }
         break;
-      case 167: /* cmd ::= UPDATE orconf fullname indexed_opt SET setlist where_opt */
+      case 169: /* cmd ::= UPDATE orconf fullname indexed_opt SET setlist where_opt */
 {
   sqlite3SrcListIndexedBy(pParse, yymsp[-4].minor.yy347, &yymsp[-3].minor.yy0);
   sqlite3ExprListCheckLength(pParse,yymsp[-1].minor.yy442,"set list"); 
-  sqlite3Update(pParse,yymsp[-4].minor.yy347,yymsp[-1].minor.yy442,yymsp[0].minor.yy122,yymsp[-5].minor.yy392);
+  sqlite3Update(pParse,yymsp[-4].minor.yy347,yymsp[-1].minor.yy442,yymsp[0].minor.yy122,yymsp[-5].minor.yy258);
 }
         break;
-      case 168: /* setlist ::= setlist COMMA nm EQ expr */
-{yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy442,yymsp[0].minor.yy122,&yymsp[-2].minor.yy0);}
+      case 170: /* setlist ::= setlist COMMA nm EQ expr */
+{
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse, yymsp[-4].minor.yy442, yymsp[0].minor.yy342.pExpr);
+  sqlite3ExprListSetName(pParse, yygotominor.yy442, &yymsp[-2].minor.yy0, 1);
+}
         break;
-      case 169: /* setlist ::= nm EQ expr */
-{yygotominor.yy442 = sqlite3ExprListAppend(pParse,0,yymsp[0].minor.yy122,&yymsp[-2].minor.yy0);}
+      case 171: /* setlist ::= nm EQ expr */
+{
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse, 0, yymsp[0].minor.yy342.pExpr);
+  sqlite3ExprListSetName(pParse, yygotominor.yy442, &yymsp[-2].minor.yy0, 1);
+}
         break;
-      case 170: /* cmd ::= insert_cmd INTO fullname inscollist_opt VALUES LP itemlist RP */
-{sqlite3Insert(pParse, yymsp[-5].minor.yy347, yymsp[-1].minor.yy442, 0, yymsp[-4].minor.yy180, yymsp[-7].minor.yy392);}
+      case 172: /* cmd ::= insert_cmd INTO fullname inscollist_opt valuelist */
+{sqlite3Insert(pParse, yymsp[-2].minor.yy347, yymsp[0].minor.yy487.pList, yymsp[0].minor.yy487.pSelect, yymsp[-1].minor.yy180, yymsp[-4].minor.yy258);}
         break;
-      case 171: /* cmd ::= insert_cmd INTO fullname inscollist_opt select */
-{sqlite3Insert(pParse, yymsp[-2].minor.yy347, 0, yymsp[0].minor.yy159, yymsp[-1].minor.yy180, yymsp[-4].minor.yy392);}
+      case 173: /* cmd ::= insert_cmd INTO fullname inscollist_opt select */
+{sqlite3Insert(pParse, yymsp[-2].minor.yy347, 0, yymsp[0].minor.yy159, yymsp[-1].minor.yy180, yymsp[-4].minor.yy258);}
         break;
-      case 172: /* cmd ::= insert_cmd INTO fullname inscollist_opt DEFAULT VALUES */
-{sqlite3Insert(pParse, yymsp[-3].minor.yy347, 0, 0, yymsp[-2].minor.yy180, yymsp[-5].minor.yy392);}
+      case 174: /* cmd ::= insert_cmd INTO fullname inscollist_opt DEFAULT VALUES */
+{sqlite3Insert(pParse, yymsp[-3].minor.yy347, 0, 0, yymsp[-2].minor.yy180, yymsp[-5].minor.yy258);}
         break;
-      case 175: /* itemlist ::= itemlist COMMA expr */
-      case 239: /* nexprlist ::= nexprlist COMMA expr */
-{yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy442,yymsp[0].minor.yy122,0);}
+      case 175: /* insert_cmd ::= INSERT orconf */
+{yygotominor.yy258 = yymsp[0].minor.yy258;}
         break;
-      case 176: /* itemlist ::= expr */
-      case 240: /* nexprlist ::= expr */
-{yygotominor.yy442 = sqlite3ExprListAppend(pParse,0,yymsp[0].minor.yy122,0);}
+      case 176: /* insert_cmd ::= REPLACE */
+{yygotominor.yy258 = OE_Replace;}
         break;
-      case 179: /* inscollist ::= inscollist COMMA nm */
+      case 177: /* valuelist ::= VALUES LP nexprlist RP */
+{
+  yygotominor.yy487.pList = yymsp[-1].minor.yy442;
+  yygotominor.yy487.pSelect = 0;
+}
+        break;
+      case 178: /* valuelist ::= valuelist COMMA LP exprlist RP */
+{
+  Select *pRight = sqlite3SelectNew(pParse, yymsp[-1].minor.yy442, 0, 0, 0, 0, 0, 0, 0, 0);
+  if( yymsp[-4].minor.yy487.pList ){
+    yymsp[-4].minor.yy487.pSelect = sqlite3SelectNew(pParse, yymsp[-4].minor.yy487.pList, 0, 0, 0, 0, 0, 0, 0, 0);
+    yymsp[-4].minor.yy487.pList = 0;
+  }
+  yygotominor.yy487.pList = 0;
+  if( yymsp[-4].minor.yy487.pSelect==0 || pRight==0 ){
+    sqlite3SelectDelete(pParse->db, pRight);
+    sqlite3SelectDelete(pParse->db, yymsp[-4].minor.yy487.pSelect);
+    yygotominor.yy487.pSelect = 0;
+  }else{
+    pRight->op = TK_ALL;
+    pRight->pPrior = yymsp[-4].minor.yy487.pSelect;
+    pRight->selFlags |= SF_Values;
+    pRight->pPrior->selFlags |= SF_Values;
+    yygotominor.yy487.pSelect = pRight;
+  }
+}
+        break;
+      case 181: /* inscollist ::= inscollist COMMA nm */
 {yygotominor.yy180 = sqlite3IdListAppend(pParse->db,yymsp[-2].minor.yy180,&yymsp[0].minor.yy0);}
         break;
-      case 180: /* inscollist ::= nm */
+      case 182: /* inscollist ::= nm */
 {yygotominor.yy180 = sqlite3IdListAppend(pParse->db,0,&yymsp[0].minor.yy0);}
         break;
-      case 182: /* expr ::= LP expr RP */
-{yygotominor.yy122 = yymsp[-1].minor.yy122; sqlite3ExprSpan(yygotominor.yy122,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0); }
+      case 183: /* expr ::= term */
+{yygotominor.yy342 = yymsp[0].minor.yy342;}
         break;
-      case 183: /* term ::= NULL */
-      case 188: /* term ::= INTEGER|FLOAT|BLOB */
-      case 189: /* term ::= STRING */
-{yygotominor.yy122 = sqlite3PExpr(pParse, yymsp[0].major, 0, 0, &yymsp[0].minor.yy0);}
+      case 184: /* expr ::= LP expr RP */
+{yygotominor.yy342.pExpr = yymsp[-1].minor.yy342.pExpr; spanSet(&yygotominor.yy342,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0);}
         break;
-      case 184: /* expr ::= ID */
-      case 185: /* expr ::= JOIN_KW */
-{yygotominor.yy122 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[0].minor.yy0);}
+      case 185: /* term ::= NULL */
+      case 190: /* term ::= INTEGER|FLOAT|BLOB */ yytestcase(yyruleno==190);
+      case 191: /* term ::= STRING */ yytestcase(yyruleno==191);
+{spanExpr(&yygotominor.yy342, pParse, yymsp[0].major, &yymsp[0].minor.yy0);}
         break;
-      case 186: /* expr ::= nm DOT nm */
+      case 186: /* expr ::= id */
+      case 187: /* expr ::= JOIN_KW */ yytestcase(yyruleno==187);
+{spanExpr(&yygotominor.yy342, pParse, TK_ID, &yymsp[0].minor.yy0);}
+        break;
+      case 188: /* expr ::= nm DOT nm */
 {
   Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-2].minor.yy0);
   Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[0].minor.yy0);
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_DOT, temp1, temp2, 0);
+  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp2, 0);
+  spanSet(&yygotominor.yy342,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0);
 }
         break;
-      case 187: /* expr ::= nm DOT nm DOT nm */
+      case 189: /* expr ::= nm DOT nm DOT nm */
 {
   Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-4].minor.yy0);
   Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[-2].minor.yy0);
   Expr *temp3 = sqlite3PExpr(pParse, TK_ID, 0, 0, &yymsp[0].minor.yy0);
   Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3, 0);
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
+  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
+  spanSet(&yygotominor.yy342,&yymsp[-4].minor.yy0,&yymsp[0].minor.yy0);
 }
         break;
-      case 190: /* expr ::= REGISTER */
-{yygotominor.yy122 = sqlite3RegisterExpr(pParse, &yymsp[0].minor.yy0);}
-        break;
-      case 191: /* expr ::= VARIABLE */
+      case 192: /* expr ::= REGISTER */
 {
-  Token *pToken = &yymsp[0].minor.yy0;
-  Expr *pExpr = yygotominor.yy122 = sqlite3PExpr(pParse, TK_VARIABLE, 0, 0, pToken);
-  sqlite3ExprAssignVarNumber(pParse, pExpr);
+  /* When doing a nested parse, one can include terms in an expression
+  ** that look like this:   #1 #2 ...  These terms refer to registers
+  ** in the virtual machine.  #N is the N-th register. */
+  if( pParse->nested==0 ){
+    sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &yymsp[0].minor.yy0);
+    yygotominor.yy342.pExpr = 0;
+  }else{
+    yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, &yymsp[0].minor.yy0);
+    if( yygotominor.yy342.pExpr ) sqlite3GetInt32(&yymsp[0].minor.yy0.z[1], &yygotominor.yy342.pExpr->iTable);
+  }
+  spanSet(&yygotominor.yy342, &yymsp[0].minor.yy0, &yymsp[0].minor.yy0);
 }
         break;
-      case 192: /* expr ::= expr COLLATE ids */
+      case 193: /* expr ::= VARIABLE */
 {
-  yygotominor.yy122 = sqlite3ExprSetColl(pParse, yymsp[-2].minor.yy122, &yymsp[0].minor.yy0);
+  spanExpr(&yygotominor.yy342, pParse, TK_VARIABLE, &yymsp[0].minor.yy0);
+  sqlite3ExprAssignVarNumber(pParse, yygotominor.yy342.pExpr);
+  spanSet(&yygotominor.yy342, &yymsp[0].minor.yy0, &yymsp[0].minor.yy0);
 }
         break;
-      case 193: /* expr ::= CAST LP expr AS typetoken RP */
+      case 194: /* expr ::= expr COLLATE ids */
 {
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_CAST, yymsp[-3].minor.yy122, 0, &yymsp[-1].minor.yy0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-5].minor.yy0,&yymsp[0].minor.yy0);
+  yygotominor.yy342.pExpr = sqlite3ExprSetCollByToken(pParse, yymsp[-2].minor.yy342.pExpr, &yymsp[0].minor.yy0);
+  yygotominor.yy342.zStart = yymsp[-2].minor.yy342.zStart;
+  yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
 }
         break;
-      case 194: /* expr ::= ID LP distinct exprlist RP */
+      case 195: /* expr ::= CAST LP expr AS typetoken RP */
 {
-  if( yymsp[-1].minor.yy442 && yymsp[-1].minor.yy442->nExpr>SQLITE_MAX_FUNCTION_ARG ){
+  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_CAST, yymsp[-3].minor.yy342.pExpr, 0, &yymsp[-1].minor.yy0);
+  spanSet(&yygotominor.yy342,&yymsp[-5].minor.yy0,&yymsp[0].minor.yy0);
+}
+        break;
+      case 196: /* expr ::= ID LP distinct exprlist RP */
+{
+  if( yymsp[-1].minor.yy442 && yymsp[-1].minor.yy442->nExpr>pParse->db->aLimit[SQLITE_LIMIT_FUNCTION_ARG] ){
     sqlite3ErrorMsg(pParse, "too many arguments on function %T", &yymsp[-4].minor.yy0);
   }
-  yygotominor.yy122 = sqlite3ExprFunction(pParse, yymsp[-1].minor.yy442, &yymsp[-4].minor.yy0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-4].minor.yy0,&yymsp[0].minor.yy0);
-  if( yymsp[-2].minor.yy392 && yygotominor.yy122 ){
-    yygotominor.yy122->flags |= EP_Distinct;
+  yygotominor.yy342.pExpr = sqlite3ExprFunction(pParse, yymsp[-1].minor.yy442, &yymsp[-4].minor.yy0);
+  spanSet(&yygotominor.yy342,&yymsp[-4].minor.yy0,&yymsp[0].minor.yy0);
+  if( yymsp[-2].minor.yy392 && yygotominor.yy342.pExpr ){
+    yygotominor.yy342.pExpr->flags |= EP_Distinct;
   }
 }
         break;
-      case 195: /* expr ::= ID LP STAR RP */
+      case 197: /* expr ::= ID LP STAR RP */
 {
-  yygotominor.yy122 = sqlite3ExprFunction(pParse, 0, &yymsp[-3].minor.yy0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-3].minor.yy0,&yymsp[0].minor.yy0);
+  yygotominor.yy342.pExpr = sqlite3ExprFunction(pParse, 0, &yymsp[-3].minor.yy0);
+  spanSet(&yygotominor.yy342,&yymsp[-3].minor.yy0,&yymsp[0].minor.yy0);
 }
         break;
-      case 196: /* term ::= CTIME_KW */
+      case 198: /* term ::= CTIME_KW */
 {
   /* The CURRENT_TIME, CURRENT_DATE, and CURRENT_TIMESTAMP values are
   ** treated as functions that return constants */
-  yygotominor.yy122 = sqlite3ExprFunction(pParse, 0,&yymsp[0].minor.yy0);
-  if( yygotominor.yy122 ){
-    yygotominor.yy122->op = TK_CONST_FUNC;  
-    yygotominor.yy122->span = yymsp[0].minor.yy0;
+  yygotominor.yy342.pExpr = sqlite3ExprFunction(pParse, 0,&yymsp[0].minor.yy0);
+  if( yygotominor.yy342.pExpr ){
+    yygotominor.yy342.pExpr->op = TK_CONST_FUNC;  
   }
+  spanSet(&yygotominor.yy342, &yymsp[0].minor.yy0, &yymsp[0].minor.yy0);
 }
         break;
-      case 197: /* expr ::= expr AND expr */
-      case 198: /* expr ::= expr OR expr */
-      case 199: /* expr ::= expr LT|GT|GE|LE expr */
-      case 200: /* expr ::= expr EQ|NE expr */
-      case 201: /* expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */
-      case 202: /* expr ::= expr PLUS|MINUS expr */
-      case 203: /* expr ::= expr STAR|SLASH|REM expr */
-      case 204: /* expr ::= expr CONCAT expr */
-{yygotominor.yy122 = sqlite3PExpr(pParse,yymsp[-1].major,yymsp[-2].minor.yy122,yymsp[0].minor.yy122,0);}
+      case 199: /* expr ::= expr AND expr */
+      case 200: /* expr ::= expr OR expr */ yytestcase(yyruleno==200);
+      case 201: /* expr ::= expr LT|GT|GE|LE expr */ yytestcase(yyruleno==201);
+      case 202: /* expr ::= expr EQ|NE expr */ yytestcase(yyruleno==202);
+      case 203: /* expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */ yytestcase(yyruleno==203);
+      case 204: /* expr ::= expr PLUS|MINUS expr */ yytestcase(yyruleno==204);
+      case 205: /* expr ::= expr STAR|SLASH|REM expr */ yytestcase(yyruleno==205);
+      case 206: /* expr ::= expr CONCAT expr */ yytestcase(yyruleno==206);
+{spanBinaryExpr(&yygotominor.yy342,pParse,yymsp[-1].major,&yymsp[-2].minor.yy342,&yymsp[0].minor.yy342);}
         break;
-      case 205: /* likeop ::= LIKE_KW */
-      case 207: /* likeop ::= MATCH */
-{yygotominor.yy318.eOperator = yymsp[0].minor.yy0; yygotominor.yy318.not = 0;}
+      case 207: /* likeop ::= LIKE_KW */
+      case 209: /* likeop ::= MATCH */ yytestcase(yyruleno==209);
+{yygotominor.yy318.eOperator = yymsp[0].minor.yy0; yygotominor.yy318.bNot = 0;}
         break;
-      case 206: /* likeop ::= NOT LIKE_KW */
-      case 208: /* likeop ::= NOT MATCH */
-{yygotominor.yy318.eOperator = yymsp[0].minor.yy0; yygotominor.yy318.not = 1;}
+      case 208: /* likeop ::= NOT LIKE_KW */
+      case 210: /* likeop ::= NOT MATCH */ yytestcase(yyruleno==210);
+{yygotominor.yy318.eOperator = yymsp[0].minor.yy0; yygotominor.yy318.bNot = 1;}
         break;
-      case 211: /* expr ::= expr likeop expr escape */
+      case 211: /* expr ::= expr likeop expr */
 {
   ExprList *pList;
-  pList = sqlite3ExprListAppend(pParse,0, yymsp[-1].minor.yy122, 0);
-  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-3].minor.yy122, 0);
-  if( yymsp[0].minor.yy122 ){
-    pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy122, 0);
-  }
-  yygotominor.yy122 = sqlite3ExprFunction(pParse, pList, &yymsp[-2].minor.yy318.eOperator);
-  if( yymsp[-2].minor.yy318.not ) yygotominor.yy122 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122, &yymsp[-3].minor.yy122->span, &yymsp[-1].minor.yy122->span);
-  if( yygotominor.yy122 ) yygotominor.yy122->flags |= EP_InfixFunc;
+  pList = sqlite3ExprListAppend(pParse,0, yymsp[0].minor.yy342.pExpr);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-2].minor.yy342.pExpr);
+  yygotominor.yy342.pExpr = sqlite3ExprFunction(pParse, pList, &yymsp[-1].minor.yy318.eOperator);
+  if( yymsp[-1].minor.yy318.bNot ) yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy342.pExpr, 0, 0);
+  yygotominor.yy342.zStart = yymsp[-2].minor.yy342.zStart;
+  yygotominor.yy342.zEnd = yymsp[0].minor.yy342.zEnd;
+  if( yygotominor.yy342.pExpr ) yygotominor.yy342.pExpr->flags |= EP_InfixFunc;
 }
         break;
-      case 212: /* expr ::= expr ISNULL|NOTNULL */
+      case 212: /* expr ::= expr likeop expr ESCAPE expr */
 {
-  yygotominor.yy122 = sqlite3PExpr(pParse, yymsp[0].major, yymsp[-1].minor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-1].minor.yy122->span,&yymsp[0].minor.yy0);
+  ExprList *pList;
+  pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy342.pExpr);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-4].minor.yy342.pExpr);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy342.pExpr);
+  yygotominor.yy342.pExpr = sqlite3ExprFunction(pParse, pList, &yymsp[-3].minor.yy318.eOperator);
+  if( yymsp[-3].minor.yy318.bNot ) yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy342.pExpr, 0, 0);
+  yygotominor.yy342.zStart = yymsp[-4].minor.yy342.zStart;
+  yygotominor.yy342.zEnd = yymsp[0].minor.yy342.zEnd;
+  if( yygotominor.yy342.pExpr ) yygotominor.yy342.pExpr->flags |= EP_InfixFunc;
 }
         break;
-      case 213: /* expr ::= expr IS NULL */
-{
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_ISNULL, yymsp[-2].minor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-2].minor.yy122->span,&yymsp[0].minor.yy0);
-}
+      case 213: /* expr ::= expr ISNULL|NOTNULL */
+{spanUnaryPostfix(&yygotominor.yy342,pParse,yymsp[0].major,&yymsp[-1].minor.yy342,&yymsp[0].minor.yy0);}
         break;
       case 214: /* expr ::= expr NOT NULL */
+{spanUnaryPostfix(&yygotominor.yy342,pParse,TK_NOTNULL,&yymsp[-2].minor.yy342,&yymsp[0].minor.yy0);}
+        break;
+      case 215: /* expr ::= expr IS expr */
 {
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_NOTNULL, yymsp[-2].minor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-2].minor.yy122->span,&yymsp[0].minor.yy0);
+  spanBinaryExpr(&yygotominor.yy342,pParse,TK_IS,&yymsp[-2].minor.yy342,&yymsp[0].minor.yy342);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy342.pExpr, yygotominor.yy342.pExpr, TK_ISNULL);
 }
         break;
-      case 215: /* expr ::= expr IS NOT NULL */
+      case 216: /* expr ::= expr IS NOT expr */
 {
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_NOTNULL, yymsp[-3].minor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-3].minor.yy122->span,&yymsp[0].minor.yy0);
+  spanBinaryExpr(&yygotominor.yy342,pParse,TK_ISNOT,&yymsp[-3].minor.yy342,&yymsp[0].minor.yy342);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy342.pExpr, yygotominor.yy342.pExpr, TK_NOTNULL);
 }
         break;
-      case 216: /* expr ::= NOT expr */
-      case 217: /* expr ::= BITNOT expr */
-{
-  yygotominor.yy122 = sqlite3PExpr(pParse, yymsp[-1].major, yymsp[0].minor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy122->span);
-}
+      case 217: /* expr ::= NOT expr */
+      case 218: /* expr ::= BITNOT expr */ yytestcase(yyruleno==218);
+{spanUnaryPrefix(&yygotominor.yy342,pParse,yymsp[-1].major,&yymsp[0].minor.yy342,&yymsp[-1].minor.yy0);}
         break;
-      case 218: /* expr ::= MINUS expr */
-{
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_UMINUS, yymsp[0].minor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy122->span);
-}
+      case 219: /* expr ::= MINUS expr */
+{spanUnaryPrefix(&yygotominor.yy342,pParse,TK_UMINUS,&yymsp[0].minor.yy342,&yymsp[-1].minor.yy0);}
         break;
-      case 219: /* expr ::= PLUS expr */
-{
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_UPLUS, yymsp[0].minor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy122->span);
-}
+      case 220: /* expr ::= PLUS expr */
+{spanUnaryPrefix(&yygotominor.yy342,pParse,TK_UPLUS,&yymsp[0].minor.yy342,&yymsp[-1].minor.yy0);}
         break;
-      case 222: /* expr ::= expr between_op expr AND expr */
+      case 223: /* expr ::= expr between_op expr AND expr */
 {
-  ExprList *pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy122, 0);
-  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy122, 0);
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_BETWEEN, yymsp[-4].minor.yy122, 0, 0);
-  if( yygotominor.yy122 ){
-    yygotominor.yy122->pList = pList;
+  ExprList *pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy342.pExpr);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy342.pExpr);
+  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_BETWEEN, yymsp[-4].minor.yy342.pExpr, 0, 0);
+  if( yygotominor.yy342.pExpr ){
+    yygotominor.yy342.pExpr->x.pList = pList;
   }else{
     sqlite3ExprListDelete(pParse->db, pList);
   } 
-  if( yymsp[-3].minor.yy392 ) yygotominor.yy122 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy122, 0, 0);
-  sqlite3ExprSpan(yygotominor.yy122,&yymsp[-4].minor.yy122->span,&yymsp[0].minor.yy122->span);
+  if( yymsp[-3].minor.yy392 ) yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy342.pExpr, 0, 0);
+  yygotominor.yy342.zStart = yymsp[-4].minor.yy342.zStart;
+  yygotominor.yy342.zEnd = yymsp[0].minor.yy342.zEnd;
 }
         break;
-      case 225: /* expr ::= expr in_op LP exprlist RP */
+      case 226: /* expr ::= expr in_op LP exprlist RP */
 {
-    yygotominor.yy122 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy122, 0, 0);
-    if( yygotominor.yy122 ){
-      yygotominor.yy122->pList = yymsp[-1].minor.yy442;
-      sqlite3ExprSetHeight(pParse, yygotominor.yy122);
+    if( yymsp[-1].minor.yy442==0 ){
+      /* Expressions of the form
+      **
+      **      expr1 IN ()
+      **      expr1 NOT IN ()
+      **
+      ** simplify to constants 0 (false) and 1 (true), respectively,
+      ** regardless of the value of expr1.
+      */
+      yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &sqlite3IntTokens[yymsp[-3].minor.yy392]);
+      sqlite3ExprDelete(pParse->db, yymsp[-4].minor.yy342.pExpr);
     }else{
-      sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy442);
+      yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy342.pExpr, 0, 0);
+      if( yygotominor.yy342.pExpr ){
+        yygotominor.yy342.pExpr->x.pList = yymsp[-1].minor.yy442;
+        sqlite3ExprSetHeight(pParse, yygotominor.yy342.pExpr);
+      }else{
+        sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy442);
+      }
+      if( yymsp[-3].minor.yy392 ) yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy342.pExpr, 0, 0);
     }
-    if( yymsp[-3].minor.yy392 ) yygotominor.yy122 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy122, 0, 0);
-    sqlite3ExprSpan(yygotominor.yy122,&yymsp[-4].minor.yy122->span,&yymsp[0].minor.yy0);
+    yygotominor.yy342.zStart = yymsp[-4].minor.yy342.zStart;
+    yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
   }
         break;
-      case 226: /* expr ::= LP select RP */
+      case 227: /* expr ::= LP select RP */
 {
-    yygotominor.yy122 = sqlite3PExpr(pParse, TK_SELECT, 0, 0, 0);
-    if( yygotominor.yy122 ){
-      yygotominor.yy122->pSelect = yymsp[-1].minor.yy159;
-      sqlite3ExprSetHeight(pParse, yygotominor.yy122);
+    yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_SELECT, 0, 0, 0);
+    if( yygotominor.yy342.pExpr ){
+      yygotominor.yy342.pExpr->x.pSelect = yymsp[-1].minor.yy159;
+      ExprSetProperty(yygotominor.yy342.pExpr, EP_xIsSelect);
+      sqlite3ExprSetHeight(pParse, yygotominor.yy342.pExpr);
     }else{
       sqlite3SelectDelete(pParse->db, yymsp[-1].minor.yy159);
     }
-    sqlite3ExprSpan(yygotominor.yy122,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0);
+    yygotominor.yy342.zStart = yymsp[-2].minor.yy0.z;
+    yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
   }
         break;
-      case 227: /* expr ::= expr in_op LP select RP */
+      case 228: /* expr ::= expr in_op LP select RP */
 {
-    yygotominor.yy122 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy122, 0, 0);
-    if( yygotominor.yy122 ){
-      yygotominor.yy122->pSelect = yymsp[-1].minor.yy159;
-      sqlite3ExprSetHeight(pParse, yygotominor.yy122);
+    yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy342.pExpr, 0, 0);
+    if( yygotominor.yy342.pExpr ){
+      yygotominor.yy342.pExpr->x.pSelect = yymsp[-1].minor.yy159;
+      ExprSetProperty(yygotominor.yy342.pExpr, EP_xIsSelect);
+      sqlite3ExprSetHeight(pParse, yygotominor.yy342.pExpr);
     }else{
       sqlite3SelectDelete(pParse->db, yymsp[-1].minor.yy159);
     }
-    if( yymsp[-3].minor.yy392 ) yygotominor.yy122 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy122, 0, 0);
-    sqlite3ExprSpan(yygotominor.yy122,&yymsp[-4].minor.yy122->span,&yymsp[0].minor.yy0);
+    if( yymsp[-3].minor.yy392 ) yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy342.pExpr, 0, 0);
+    yygotominor.yy342.zStart = yymsp[-4].minor.yy342.zStart;
+    yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
   }
         break;
-      case 228: /* expr ::= expr in_op nm dbnm */
+      case 229: /* expr ::= expr in_op nm dbnm */
 {
     SrcList *pSrc = sqlite3SrcListAppend(pParse->db, 0,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0);
-    yygotominor.yy122 = sqlite3PExpr(pParse, TK_IN, yymsp[-3].minor.yy122, 0, 0);
-    if( yygotominor.yy122 ){
-      yygotominor.yy122->pSelect = sqlite3SelectNew(pParse, 0,pSrc,0,0,0,0,0,0,0);
-      sqlite3ExprSetHeight(pParse, yygotominor.yy122);
+    yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_IN, yymsp[-3].minor.yy342.pExpr, 0, 0);
+    if( yygotominor.yy342.pExpr ){
+      yygotominor.yy342.pExpr->x.pSelect = sqlite3SelectNew(pParse, 0,pSrc,0,0,0,0,0,0,0);
+      ExprSetProperty(yygotominor.yy342.pExpr, EP_xIsSelect);
+      sqlite3ExprSetHeight(pParse, yygotominor.yy342.pExpr);
     }else{
       sqlite3SrcListDelete(pParse->db, pSrc);
     }
-    if( yymsp[-2].minor.yy392 ) yygotominor.yy122 = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy122, 0, 0);
-    sqlite3ExprSpan(yygotominor.yy122,&yymsp[-3].minor.yy122->span,yymsp[0].minor.yy0.z?&yymsp[0].minor.yy0:&yymsp[-1].minor.yy0);
+    if( yymsp[-2].minor.yy392 ) yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_NOT, yygotominor.yy342.pExpr, 0, 0);
+    yygotominor.yy342.zStart = yymsp[-3].minor.yy342.zStart;
+    yygotominor.yy342.zEnd = yymsp[0].minor.yy0.z ? &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] : &yymsp[-1].minor.yy0.z[yymsp[-1].minor.yy0.n];
   }
         break;
-      case 229: /* expr ::= EXISTS LP select RP */
+      case 230: /* expr ::= EXISTS LP select RP */
 {
-    Expr *p = yygotominor.yy122 = sqlite3PExpr(pParse, TK_EXISTS, 0, 0, 0);
+    Expr *p = yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_EXISTS, 0, 0, 0);
     if( p ){
-      p->pSelect = yymsp[-1].minor.yy159;
-      sqlite3ExprSpan(p,&yymsp[-3].minor.yy0,&yymsp[0].minor.yy0);
-      sqlite3ExprSetHeight(pParse, yygotominor.yy122);
+      p->x.pSelect = yymsp[-1].minor.yy159;
+      ExprSetProperty(p, EP_xIsSelect);
+      sqlite3ExprSetHeight(pParse, p);
     }else{
       sqlite3SelectDelete(pParse->db, yymsp[-1].minor.yy159);
     }
+    yygotominor.yy342.zStart = yymsp[-3].minor.yy0.z;
+    yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
   }
         break;
-      case 230: /* expr ::= CASE case_operand case_exprlist case_else END */
+      case 231: /* expr ::= CASE case_operand case_exprlist case_else END */
 {
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_CASE, yymsp[-3].minor.yy122, yymsp[-1].minor.yy122, 0);
-  if( yygotominor.yy122 ){
-    yygotominor.yy122->pList = yymsp[-2].minor.yy442;
-    sqlite3ExprSetHeight(pParse, yygotominor.yy122);
+  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_CASE, yymsp[-3].minor.yy122, yymsp[-1].minor.yy122, 0);
+  if( yygotominor.yy342.pExpr ){
+    yygotominor.yy342.pExpr->x.pList = yymsp[-2].minor.yy442;
+    sqlite3ExprSetHeight(pParse, yygotominor.yy342.pExpr);
   }else{
     sqlite3ExprListDelete(pParse->db, yymsp[-2].minor.yy442);
   }
-  sqlite3ExprSpan(yygotominor.yy122, &yymsp[-4].minor.yy0, &yymsp[0].minor.yy0);
+  yygotominor.yy342.zStart = yymsp[-4].minor.yy0.z;
+  yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
 }
         break;
-      case 231: /* case_exprlist ::= case_exprlist WHEN expr THEN expr */
+      case 232: /* case_exprlist ::= case_exprlist WHEN expr THEN expr */
 {
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy442, yymsp[-2].minor.yy122, 0);
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yygotominor.yy442, yymsp[0].minor.yy122, 0);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy442, yymsp[-2].minor.yy342.pExpr);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yygotominor.yy442, yymsp[0].minor.yy342.pExpr);
 }
         break;
-      case 232: /* case_exprlist ::= WHEN expr THEN expr */
+      case 233: /* case_exprlist ::= WHEN expr THEN expr */
 {
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy122, 0);
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yygotominor.yy442, yymsp[0].minor.yy122, 0);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy342.pExpr);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yygotominor.yy442, yymsp[0].minor.yy342.pExpr);
 }
         break;
-      case 241: /* cmd ::= CREATE uniqueflag INDEX ifnotexists nm dbnm ON nm LP idxlist RP */
+      case 240: /* nexprlist ::= nexprlist COMMA expr */
+{yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy442,yymsp[0].minor.yy342.pExpr);}
+        break;
+      case 241: /* nexprlist ::= expr */
+{yygotominor.yy442 = sqlite3ExprListAppend(pParse,0,yymsp[0].minor.yy342.pExpr);}
+        break;
+      case 242: /* cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP idxlist RP */
 {
   sqlite3CreateIndex(pParse, &yymsp[-6].minor.yy0, &yymsp[-5].minor.yy0, 
                      sqlite3SrcListAppend(pParse->db,0,&yymsp[-3].minor.yy0,0), yymsp[-1].minor.yy442, yymsp[-9].minor.yy392,
                       &yymsp[-10].minor.yy0, &yymsp[0].minor.yy0, SQLITE_SO_ASC, yymsp[-7].minor.yy392);
 }
         break;
-      case 242: /* uniqueflag ::= UNIQUE */
-      case 289: /* raisetype ::= ABORT */
+      case 243: /* uniqueflag ::= UNIQUE */
+      case 296: /* raisetype ::= ABORT */ yytestcase(yyruleno==296);
 {yygotominor.yy392 = OE_Abort;}
         break;
-      case 243: /* uniqueflag ::= */
+      case 244: /* uniqueflag ::= */
 {yygotominor.yy392 = OE_None;}
         break;
-      case 246: /* idxlist ::= idxlist COMMA nm collate sortorder */
+      case 247: /* idxlist ::= idxlist COMMA nm collate sortorder */
 {
   Expr *p = 0;
   if( yymsp[-1].minor.yy0.n>0 ){
-    p = sqlite3PExpr(pParse, TK_COLUMN, 0, 0, 0);
-    sqlite3ExprSetColl(pParse, p, &yymsp[-1].minor.yy0);
+    p = sqlite3Expr(pParse->db, TK_COLUMN, 0);
+    sqlite3ExprSetCollByToken(pParse, p, &yymsp[-1].minor.yy0);
   }
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy442, p, &yymsp[-2].minor.yy0);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy442, p);
+  sqlite3ExprListSetName(pParse,yygotominor.yy442,&yymsp[-2].minor.yy0,1);
   sqlite3ExprListCheckLength(pParse, yygotominor.yy442, "index");
   if( yygotominor.yy442 ) yygotominor.yy442->a[yygotominor.yy442->nExpr-1].sortOrder = (u8)yymsp[0].minor.yy392;
 }
         break;
-      case 247: /* idxlist ::= nm collate sortorder */
+      case 248: /* idxlist ::= nm collate sortorder */
 {
   Expr *p = 0;
   if( yymsp[-1].minor.yy0.n>0 ){
     p = sqlite3PExpr(pParse, TK_COLUMN, 0, 0, 0);
-    sqlite3ExprSetColl(pParse, p, &yymsp[-1].minor.yy0);
+    sqlite3ExprSetCollByToken(pParse, p, &yymsp[-1].minor.yy0);
   }
-  yygotominor.yy442 = sqlite3ExprListAppend(pParse,0, p, &yymsp[-2].minor.yy0);
+  yygotominor.yy442 = sqlite3ExprListAppend(pParse,0, p);
+  sqlite3ExprListSetName(pParse, yygotominor.yy442, &yymsp[-2].minor.yy0, 1);
   sqlite3ExprListCheckLength(pParse, yygotominor.yy442, "index");
   if( yygotominor.yy442 ) yygotominor.yy442->a[yygotominor.yy442->nExpr-1].sortOrder = (u8)yymsp[0].minor.yy392;
 }
         break;
-      case 248: /* collate ::= */
+      case 249: /* collate ::= */
 {yygotominor.yy0.z = 0; yygotominor.yy0.n = 0;}
         break;
-      case 250: /* cmd ::= DROP INDEX ifexists fullname */
+      case 251: /* cmd ::= DROP INDEX ifexists fullname */
 {sqlite3DropIndex(pParse, yymsp[0].minor.yy347, yymsp[-1].minor.yy392);}
         break;
-      case 251: /* cmd ::= VACUUM */
-      case 252: /* cmd ::= VACUUM nm */
+      case 252: /* cmd ::= VACUUM */
+      case 253: /* cmd ::= VACUUM nm */ yytestcase(yyruleno==253);
 {sqlite3Vacuum(pParse);}
         break;
-      case 253: /* cmd ::= PRAGMA nm dbnm EQ nmnum */
-      case 254: /* cmd ::= PRAGMA nm dbnm EQ ON */
-      case 255: /* cmd ::= PRAGMA nm dbnm EQ DELETE */
-{sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,0);}
-        break;
-      case 256: /* cmd ::= PRAGMA nm dbnm EQ minus_num */
-{
-  sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,1);
-}
-        break;
-      case 257: /* cmd ::= PRAGMA nm dbnm LP nmnum RP */
-{sqlite3Pragma(pParse,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-1].minor.yy0,0);}
-        break;
-      case 258: /* cmd ::= PRAGMA nm dbnm */
+      case 254: /* cmd ::= PRAGMA nm dbnm */
 {sqlite3Pragma(pParse,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0,0,0);}
         break;
-      case 266: /* cmd ::= CREATE trigger_decl BEGIN trigger_cmd_list END */
+      case 255: /* cmd ::= PRAGMA nm dbnm EQ nmnum */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,0);}
+        break;
+      case 256: /* cmd ::= PRAGMA nm dbnm LP nmnum RP */
+{sqlite3Pragma(pParse,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-1].minor.yy0,0);}
+        break;
+      case 257: /* cmd ::= PRAGMA nm dbnm EQ minus_num */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,1);}
+        break;
+      case 258: /* cmd ::= PRAGMA nm dbnm LP minus_num RP */
+{sqlite3Pragma(pParse,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-1].minor.yy0,1);}
+        break;
+      case 268: /* cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END */
 {
   Token all;
   all.z = yymsp[-3].minor.yy0.z;
@@ -85717,161 +109968,214 @@ static void yy_reduce(
   sqlite3FinishTrigger(pParse, yymsp[-1].minor.yy327, &all);
 }
         break;
-      case 267: /* trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+      case 269: /* trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
 {
   sqlite3BeginTrigger(pParse, &yymsp[-7].minor.yy0, &yymsp[-6].minor.yy0, yymsp[-5].minor.yy392, yymsp[-4].minor.yy410.a, yymsp[-4].minor.yy410.b, yymsp[-2].minor.yy347, yymsp[0].minor.yy122, yymsp[-10].minor.yy392, yymsp[-8].minor.yy392);
   yygotominor.yy0 = (yymsp[-6].minor.yy0.n==0?yymsp[-7].minor.yy0:yymsp[-6].minor.yy0);
 }
         break;
-      case 268: /* trigger_time ::= BEFORE */
-      case 271: /* trigger_time ::= */
+      case 270: /* trigger_time ::= BEFORE */
+      case 273: /* trigger_time ::= */ yytestcase(yyruleno==273);
 { yygotominor.yy392 = TK_BEFORE; }
         break;
-      case 269: /* trigger_time ::= AFTER */
+      case 271: /* trigger_time ::= AFTER */
 { yygotominor.yy392 = TK_AFTER;  }
         break;
-      case 270: /* trigger_time ::= INSTEAD OF */
+      case 272: /* trigger_time ::= INSTEAD OF */
 { yygotominor.yy392 = TK_INSTEAD;}
         break;
-      case 272: /* trigger_event ::= DELETE|INSERT */
-      case 273: /* trigger_event ::= UPDATE */
+      case 274: /* trigger_event ::= DELETE|INSERT */
+      case 275: /* trigger_event ::= UPDATE */ yytestcase(yyruleno==275);
 {yygotominor.yy410.a = yymsp[0].major; yygotominor.yy410.b = 0;}
         break;
-      case 274: /* trigger_event ::= UPDATE OF inscollist */
+      case 276: /* trigger_event ::= UPDATE OF inscollist */
 {yygotominor.yy410.a = TK_UPDATE; yygotominor.yy410.b = yymsp[0].minor.yy180;}
         break;
-      case 277: /* when_clause ::= */
-      case 294: /* key_opt ::= */
+      case 279: /* when_clause ::= */
+      case 301: /* key_opt ::= */ yytestcase(yyruleno==301);
 { yygotominor.yy122 = 0; }
         break;
-      case 278: /* when_clause ::= WHEN expr */
-      case 295: /* key_opt ::= KEY expr */
-{ yygotominor.yy122 = yymsp[0].minor.yy122; }
+      case 280: /* when_clause ::= WHEN expr */
+      case 302: /* key_opt ::= KEY expr */ yytestcase(yyruleno==302);
+{ yygotominor.yy122 = yymsp[0].minor.yy342.pExpr; }
         break;
-      case 279: /* trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+      case 281: /* trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
 {
-/*
-  if( yymsp[-2].minor.yy327 ){
-    yymsp[-2].minor.yy327->pLast->pNext = yymsp[-1].minor.yy327;
-  }else{
-    yymsp[-2].minor.yy327 = yymsp[-1].minor.yy327;
-  }
-*/
   assert( yymsp[-2].minor.yy327!=0 );
   yymsp[-2].minor.yy327->pLast->pNext = yymsp[-1].minor.yy327;
   yymsp[-2].minor.yy327->pLast = yymsp[-1].minor.yy327;
   yygotominor.yy327 = yymsp[-2].minor.yy327;
 }
         break;
-      case 280: /* trigger_cmd_list ::= trigger_cmd SEMI */
+      case 282: /* trigger_cmd_list ::= trigger_cmd SEMI */
 { 
-  /* if( yymsp[-1].minor.yy327 ) */
   assert( yymsp[-1].minor.yy327!=0 );
   yymsp[-1].minor.yy327->pLast = yymsp[-1].minor.yy327;
   yygotominor.yy327 = yymsp[-1].minor.yy327;
 }
         break;
-      case 281: /* trigger_cmd ::= UPDATE orconf nm SET setlist where_opt */
-{ yygotominor.yy327 = sqlite3TriggerUpdateStep(pParse->db, &yymsp[-3].minor.yy0, yymsp[-1].minor.yy442, yymsp[0].minor.yy122, yymsp[-4].minor.yy392); }
+      case 284: /* trnm ::= nm DOT nm */
+{
+  yygotominor.yy0 = yymsp[0].minor.yy0;
+  sqlite3ErrorMsg(pParse, 
+        "qualified table names are not allowed on INSERT, UPDATE, and DELETE "
+        "statements within triggers");
+}
         break;
-      case 282: /* trigger_cmd ::= insert_cmd INTO nm inscollist_opt VALUES LP itemlist RP */
-{yygotominor.yy327 = sqlite3TriggerInsertStep(pParse->db, &yymsp[-5].minor.yy0, yymsp[-4].minor.yy180, yymsp[-1].minor.yy442, 0, yymsp[-7].minor.yy392);}
+      case 286: /* tridxby ::= INDEXED BY nm */
+{
+  sqlite3ErrorMsg(pParse,
+        "the INDEXED BY clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
         break;
-      case 283: /* trigger_cmd ::= insert_cmd INTO nm inscollist_opt select */
-{yygotominor.yy327 = sqlite3TriggerInsertStep(pParse->db, &yymsp[-2].minor.yy0, yymsp[-1].minor.yy180, 0, yymsp[0].minor.yy159, yymsp[-4].minor.yy392);}
+      case 287: /* tridxby ::= NOT INDEXED */
+{
+  sqlite3ErrorMsg(pParse,
+        "the NOT INDEXED clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
         break;
-      case 284: /* trigger_cmd ::= DELETE FROM nm where_opt */
-{yygotominor.yy327 = sqlite3TriggerDeleteStep(pParse->db, &yymsp[-1].minor.yy0, yymsp[0].minor.yy122);}
+      case 288: /* trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist where_opt */
+{ yygotominor.yy327 = sqlite3TriggerUpdateStep(pParse->db, &yymsp[-4].minor.yy0, yymsp[-1].minor.yy442, yymsp[0].minor.yy122, yymsp[-5].minor.yy258); }
         break;
-      case 285: /* trigger_cmd ::= select */
+      case 289: /* trigger_cmd ::= insert_cmd INTO trnm inscollist_opt valuelist */
+{yygotominor.yy327 = sqlite3TriggerInsertStep(pParse->db, &yymsp[-2].minor.yy0, yymsp[-1].minor.yy180, yymsp[0].minor.yy487.pList, yymsp[0].minor.yy487.pSelect, yymsp[-4].minor.yy258);}
+        break;
+      case 290: /* trigger_cmd ::= insert_cmd INTO trnm inscollist_opt select */
+{yygotominor.yy327 = sqlite3TriggerInsertStep(pParse->db, &yymsp[-2].minor.yy0, yymsp[-1].minor.yy180, 0, yymsp[0].minor.yy159, yymsp[-4].minor.yy258);}
+        break;
+      case 291: /* trigger_cmd ::= DELETE FROM trnm tridxby where_opt */
+{yygotominor.yy327 = sqlite3TriggerDeleteStep(pParse->db, &yymsp[-2].minor.yy0, yymsp[0].minor.yy122);}
+        break;
+      case 292: /* trigger_cmd ::= select */
 {yygotominor.yy327 = sqlite3TriggerSelectStep(pParse->db, yymsp[0].minor.yy159); }
         break;
-      case 286: /* expr ::= RAISE LP IGNORE RP */
+      case 293: /* expr ::= RAISE LP IGNORE RP */
 {
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_RAISE, 0, 0, 0); 
-  if( yygotominor.yy122 ){
-    yygotominor.yy122->iColumn = OE_Ignore;
-    sqlite3ExprSpan(yygotominor.yy122, &yymsp[-3].minor.yy0, &yymsp[0].minor.yy0);
+  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_RAISE, 0, 0, 0); 
+  if( yygotominor.yy342.pExpr ){
+    yygotominor.yy342.pExpr->affinity = OE_Ignore;
   }
+  yygotominor.yy342.zStart = yymsp[-3].minor.yy0.z;
+  yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
 }
         break;
-      case 287: /* expr ::= RAISE LP raisetype COMMA nm RP */
+      case 294: /* expr ::= RAISE LP raisetype COMMA nm RP */
 {
-  yygotominor.yy122 = sqlite3PExpr(pParse, TK_RAISE, 0, 0, &yymsp[-1].minor.yy0); 
-  if( yygotominor.yy122 ) {
-    yygotominor.yy122->iColumn = yymsp[-3].minor.yy392;
-    sqlite3ExprSpan(yygotominor.yy122, &yymsp[-5].minor.yy0, &yymsp[0].minor.yy0);
+  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_RAISE, 0, 0, &yymsp[-1].minor.yy0); 
+  if( yygotominor.yy342.pExpr ) {
+    yygotominor.yy342.pExpr->affinity = (char)yymsp[-3].minor.yy392;
   }
+  yygotominor.yy342.zStart = yymsp[-5].minor.yy0.z;
+  yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
 }
         break;
-      case 288: /* raisetype ::= ROLLBACK */
+      case 295: /* raisetype ::= ROLLBACK */
 {yygotominor.yy392 = OE_Rollback;}
         break;
-      case 290: /* raisetype ::= FAIL */
+      case 297: /* raisetype ::= FAIL */
 {yygotominor.yy392 = OE_Fail;}
         break;
-      case 291: /* cmd ::= DROP TRIGGER ifexists fullname */
+      case 298: /* cmd ::= DROP TRIGGER ifexists fullname */
 {
   sqlite3DropTrigger(pParse,yymsp[0].minor.yy347,yymsp[-1].minor.yy392);
 }
         break;
-      case 292: /* cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+      case 299: /* cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
 {
-  sqlite3Attach(pParse, yymsp[-3].minor.yy122, yymsp[-1].minor.yy122, yymsp[0].minor.yy122);
+  sqlite3Attach(pParse, yymsp[-3].minor.yy342.pExpr, yymsp[-1].minor.yy342.pExpr, yymsp[0].minor.yy122);
 }
         break;
-      case 293: /* cmd ::= DETACH database_kw_opt expr */
+      case 300: /* cmd ::= DETACH database_kw_opt expr */
 {
-  sqlite3Detach(pParse, yymsp[0].minor.yy122);
+  sqlite3Detach(pParse, yymsp[0].minor.yy342.pExpr);
 }
         break;
-      case 298: /* cmd ::= REINDEX */
+      case 305: /* cmd ::= REINDEX */
 {sqlite3Reindex(pParse, 0, 0);}
         break;
-      case 299: /* cmd ::= REINDEX nm dbnm */
+      case 306: /* cmd ::= REINDEX nm dbnm */
 {sqlite3Reindex(pParse, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy0);}
         break;
-      case 300: /* cmd ::= ANALYZE */
+      case 307: /* cmd ::= ANALYZE */
 {sqlite3Analyze(pParse, 0, 0);}
         break;
-      case 301: /* cmd ::= ANALYZE nm dbnm */
+      case 308: /* cmd ::= ANALYZE nm dbnm */
 {sqlite3Analyze(pParse, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy0);}
         break;
-      case 302: /* cmd ::= ALTER TABLE fullname RENAME TO nm */
+      case 309: /* cmd ::= ALTER TABLE fullname RENAME TO nm */
 {
   sqlite3AlterRenameTable(pParse,yymsp[-3].minor.yy347,&yymsp[0].minor.yy0);
 }
         break;
-      case 303: /* cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column */
+      case 310: /* cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column */
 {
   sqlite3AlterFinishAddColumn(pParse, &yymsp[0].minor.yy0);
 }
         break;
-      case 304: /* add_column_fullname ::= fullname */
+      case 311: /* add_column_fullname ::= fullname */
 {
+  pParse->db->lookaside.bEnabled = 0;
   sqlite3AlterBeginAddColumn(pParse, yymsp[0].minor.yy347);
 }
         break;
-      case 307: /* cmd ::= create_vtab */
+      case 314: /* cmd ::= create_vtab */
 {sqlite3VtabFinishParse(pParse,0);}
         break;
-      case 308: /* cmd ::= create_vtab LP vtabarglist RP */
+      case 315: /* cmd ::= create_vtab LP vtabarglist RP */
 {sqlite3VtabFinishParse(pParse,&yymsp[0].minor.yy0);}
         break;
-      case 309: /* create_vtab ::= CREATE VIRTUAL TABLE nm dbnm USING nm */
+      case 316: /* create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm */
 {
-    sqlite3VtabBeginParse(pParse, &yymsp[-3].minor.yy0, &yymsp[-2].minor.yy0, &yymsp[0].minor.yy0);
+    sqlite3VtabBeginParse(pParse, &yymsp[-3].minor.yy0, &yymsp[-2].minor.yy0, &yymsp[0].minor.yy0, yymsp[-4].minor.yy392);
 }
         break;
-      case 312: /* vtabarg ::= */
+      case 319: /* vtabarg ::= */
 {sqlite3VtabArgInit(pParse);}
         break;
-      case 314: /* vtabargtoken ::= ANY */
-      case 315: /* vtabargtoken ::= lp anylist RP */
-      case 316: /* lp ::= LP */
-      case 318: /* anylist ::= anylist ANY */
+      case 321: /* vtabargtoken ::= ANY */
+      case 322: /* vtabargtoken ::= lp anylist RP */ yytestcase(yyruleno==322);
+      case 323: /* lp ::= LP */ yytestcase(yyruleno==323);
 {sqlite3VtabArgExtend(pParse,&yymsp[0].minor.yy0);}
         break;
+      default:
+      /* (0) input ::= cmdlist */ yytestcase(yyruleno==0);
+      /* (1) cmdlist ::= cmdlist ecmd */ yytestcase(yyruleno==1);
+      /* (2) cmdlist ::= ecmd */ yytestcase(yyruleno==2);
+      /* (3) ecmd ::= SEMI */ yytestcase(yyruleno==3);
+      /* (4) ecmd ::= explain cmdx SEMI */ yytestcase(yyruleno==4);
+      /* (10) trans_opt ::= */ yytestcase(yyruleno==10);
+      /* (11) trans_opt ::= TRANSACTION */ yytestcase(yyruleno==11);
+      /* (12) trans_opt ::= TRANSACTION nm */ yytestcase(yyruleno==12);
+      /* (20) savepoint_opt ::= SAVEPOINT */ yytestcase(yyruleno==20);
+      /* (21) savepoint_opt ::= */ yytestcase(yyruleno==21);
+      /* (25) cmd ::= create_table create_table_args */ yytestcase(yyruleno==25);
+      /* (34) columnlist ::= columnlist COMMA column */ yytestcase(yyruleno==34);
+      /* (35) columnlist ::= column */ yytestcase(yyruleno==35);
+      /* (44) type ::= */ yytestcase(yyruleno==44);
+      /* (51) signed ::= plus_num */ yytestcase(yyruleno==51);
+      /* (52) signed ::= minus_num */ yytestcase(yyruleno==52);
+      /* (53) carglist ::= carglist ccons */ yytestcase(yyruleno==53);
+      /* (54) carglist ::= */ yytestcase(yyruleno==54);
+      /* (61) ccons ::= NULL onconf */ yytestcase(yyruleno==61);
+      /* (89) conslist ::= conslist tconscomma tcons */ yytestcase(yyruleno==89);
+      /* (90) conslist ::= tcons */ yytestcase(yyruleno==90);
+      /* (92) tconscomma ::= */ yytestcase(yyruleno==92);
+      /* (277) foreach_clause ::= */ yytestcase(yyruleno==277);
+      /* (278) foreach_clause ::= FOR EACH ROW */ yytestcase(yyruleno==278);
+      /* (285) tridxby ::= */ yytestcase(yyruleno==285);
+      /* (303) database_kw_opt ::= DATABASE */ yytestcase(yyruleno==303);
+      /* (304) database_kw_opt ::= */ yytestcase(yyruleno==304);
+      /* (312) kwcolumn_opt ::= */ yytestcase(yyruleno==312);
+      /* (313) kwcolumn_opt ::= COLUMNKW */ yytestcase(yyruleno==313);
+      /* (317) vtabarglist ::= vtabarg */ yytestcase(yyruleno==317);
+      /* (318) vtabarglist ::= vtabarglist COMMA vtabarg */ yytestcase(yyruleno==318);
+      /* (320) vtabarg ::= vtabarg vtabargtoken */ yytestcase(yyruleno==320);
+      /* (324) anylist ::= */ yytestcase(yyruleno==324);
+      /* (325) anylist ::= anylist LP anylist RP */ yytestcase(yyruleno==325);
+      /* (326) anylist ::= anylist ANY */ yytestcase(yyruleno==326);
+        break;
   };
   yygoto = yyRuleInfo[yyruleno].lhs;
   yysize = yyRuleInfo[yyruleno].nrhs;
@@ -85886,8 +110190,8 @@ static void yy_reduce(
     if( yysize ){
       yypParser->yyidx++;
       yymsp -= yysize-1;
-      yymsp->stateno = yyact;
-      yymsp->major = yygoto;
+      yymsp->stateno = (YYACTIONTYPE)yyact;
+      yymsp->major = (YYCODETYPE)yygoto;
       yymsp->minor = yygotominor;
     }else
 #endif
@@ -85903,6 +110207,7 @@ static void yy_reduce(
 /*
 ** The following code executes when the parse fails
 */
+#ifndef YYNOERRORRECOVERY
 static void yy_parse_failed(
   yyParser *yypParser           /* The parser */
 ){
@@ -85917,6 +110222,7 @@ static void yy_parse_failed(
   ** parser fails */
   sqlite3ParserARG_STORE; /* Suppress warning about unused %extra_argument variable */
 }
+#endif /* YYNOERRORRECOVERY */
 
 /*
 ** The following code executes when a syntax error first occurs.
@@ -85932,7 +110238,6 @@ static void yy_syntax_error(
   UNUSED_PARAMETER(yymajor);  /* Silence some compiler warnings */
   assert( TOKEN.z[0] );  /* The tokenizer always gives us a token */
   sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &TOKEN);
-  pParse->parseError = 1;
   sqlite3ParserARG_STORE; /* Suppress warning about unused %extra_argument variable */
 }
 
@@ -85981,7 +110286,9 @@ SQLITE_PRIVATE void sqlite3Parser(
 ){
   YYMINORTYPE yyminorunion;
   int yyact;            /* The parser action. */
+#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
   int yyendofinput;     /* True if we are at the end of input */
+#endif
 #ifdef YYERRORSYMBOL
   int yyerrorhit = 0;   /* True if yymajor has invoked an error */
 #endif
@@ -86004,7 +110311,9 @@ SQLITE_PRIVATE void sqlite3Parser(
     yypParser->yystack[0].major = 0;
   }
   yyminorunion.yy0 = yyminor;
+#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
   yyendofinput = (yymajor==0);
+#endif
   sqlite3ParserARG_STORE;
 
 #ifndef NDEBUG
@@ -86016,7 +110325,6 @@ SQLITE_PRIVATE void sqlite3Parser(
   do{
     yyact = yy_find_shift_action(yypParser,(YYCODETYPE)yymajor);
     if( yyact<YYNSTATE ){
-      assert( !yyendofinput );  /* Impossible to shift the $ token */
       yy_shift(yypParser,yyact,yymajor,&yyminorunion);
       yypParser->yyerrcnt--;
       yymajor = YYNOCODE;
@@ -86087,6 +110395,18 @@ SQLITE_PRIVATE void sqlite3Parser(
       }
       yypParser->yyerrcnt = 3;
       yyerrorhit = 1;
+#elif defined(YYNOERRORRECOVERY)
+      /* If the YYNOERRORRECOVERY macro is defined, then do not attempt to
+      ** do any kind of error recovery.  Instead, simply invoke the syntax
+      ** error routine and continue going as if nothing had happened.
+      **
+      ** Applications can set this macro (for example inside %include) if
+      ** they intend to abandon the parse upon the first syntax error seen.
+      */
+      yy_syntax_error(yypParser,yymajor,yyminorunion);
+      yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+      yymajor = YYNOCODE;
+      
 #else  /* YYERRORSYMBOL is not defined */
       /* This is what we do if the grammar does not define ERROR:
       **
@@ -86130,9 +110450,8 @@ SQLITE_PRIVATE void sqlite3Parser(
 ** This file contains C code that splits an SQL input string up into
 ** individual tokens and sends those tokens one-by-one over to the
 ** parser for analysis.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
+/* #include <stdlib.h> */
 
 /*
 ** The charMap() macro maps alphabetic characters into their
@@ -86184,7 +110503,7 @@ const unsigned char ebcdicToAscii[] = {
 **
 ** The code in this file has been automatically generated by
 **
-**     $Header: /test/repos/sqlite/sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+**   sqlite/tool/mkkeywordhash.c
 **
 ** The code in this file implements a function that determines whether
 ** or not a given identifier is really an SQL keyword.  The same thing
@@ -86193,9 +110512,9 @@ const unsigned char ebcdicToAscii[] = {
 ** is substantially reduced.  This is important for embedded applications
 ** on platforms with limited memory.
 */
-/* Hash score: 171 */
+/* Hash score: 175 */
 static int keywordCode(const char *z, int n){
-  /* zText[] encodes 801 bytes of keywords in 541 bytes */
+  /* zText[] encodes 811 bytes of keywords in 541 bytes */
   /*   REINDEXEDESCAPEACHECKEYBEFOREIGNOREGEXPLAINSTEADDATABASELECT       */
   /*   ABLEFTHENDEFERRABLELSEXCEPTRANSACTIONATURALTERAISEXCLUSIVE         */
   /*   XISTSAVEPOINTERSECTRIGGEREFERENCESCONSTRAINTOFFSETEMPORARY         */
@@ -86239,78 +110558,79 @@ static int keywordCode(const char *z, int n){
     'A','C','U','U','M','V','I','E','W','I','N','I','T','I','A','L','L','Y',
   };
   static const unsigned char aHash[127] = {
-      70,  99, 112,  68,   0,  43,   0,   0,  76,   0,  71,   0,   0,
-      41,  12,  72,  15,   0, 111,  79,  49, 106,   0,  19,   0,   0,
-     116,   0, 114, 109,   0,  22,  87,   0,   9,   0,   0,  64,  65,
-       0,  63,   6,   0,  47,  84,  96,   0, 113,  95,   0,   0,  44,
-       0,  97,  24,   0,  17,   0, 117,  48,  23,   0,   5, 104,  25,
-      90,   0,   0, 119, 100,  55, 118,  52,   7,  50,   0,  85,   0,
-      94,  26,   0,  93,   0,   0,   0,  89,  86,  91,  82, 103,  14,
-      38, 102,   0,  75,   0,  18,  83, 105,  31,   0, 115,  74, 107,
-      57,  45,  78,   0,   0,  88,  39,   0, 110,   0,  35,   0,   0,
-      28,   0,  80,  53,  58,   0,  20,  56,   0,  51,
+      72, 101, 114,  70,   0,  45,   0,   0,  78,   0,  73,   0,   0,
+      42,  12,  74,  15,   0, 113,  81,  50, 108,   0,  19,   0,   0,
+     118,   0, 116, 111,   0,  22,  89,   0,   9,   0,   0,  66,  67,
+       0,  65,   6,   0,  48,  86,  98,   0, 115,  97,   0,   0,  44,
+       0,  99,  24,   0,  17,   0, 119,  49,  23,   0,   5, 106,  25,
+      92,   0,   0, 121, 102,  56, 120,  53,  28,  51,   0,  87,   0,
+      96,  26,   0,  95,   0,   0,   0,  91,  88,  93,  84, 105,  14,
+      39, 104,   0,  77,   0,  18,  85, 107,  32,   0, 117,  76, 109,
+      58,  46,  80,   0,   0,  90,  40,   0, 112,   0,  36,   0,   0,
+      29,   0,  82,  59,  60,   0,  20,  57,   0,  52,
   };
-  static const unsigned char aNext[119] = {
+  static const unsigned char aNext[121] = {
        0,   0,   0,   0,   4,   0,   0,   0,   0,   0,   0,   0,   0,
        0,   2,   0,   0,   0,   0,   0,   0,  13,   0,   0,   0,   0,
-       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
-       0,   0,   0,   0,  32,  21,   0,   0,   0,  42,   3,  46,   0,
-       0,   0,   0,  29,   0,   0,  37,   0,   0,   0,   1,  60,   0,
-       0,  61,   0,  40,   0,   0,   0,   0,   0,   0,   0,  59,   0,
-       0,   0,   0,  30,  54,  16,  33,  10,   0,   0,   0,   0,   0,
-       0,   0,  11,  66,  73,   0,   8,   0,  98,  92,   0, 101,   0,
-      81,   0,  69,   0,   0, 108,  27,  36,  67,  77,   0,  34,  62,
-       0,   0,
+       0,   7,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,  33,   0,  21,   0,   0,   0,  43,   3,  47,
+       0,   0,   0,   0,  30,   0,  54,   0,  38,   0,   0,   0,   1,
+      62,   0,   0,  63,   0,  41,   0,   0,   0,   0,   0,   0,   0,
+      61,   0,   0,   0,   0,  31,  55,  16,  34,  10,   0,   0,   0,
+       0,   0,   0,   0,  11,  68,  75,   0,   8,   0, 100,  94,   0,
+     103,   0,  83,   0,  71,   0,   0, 110,  27,  37,  69,  79,   0,
+      35,  64,   0,   0,
   };
-  static const unsigned char aLen[119] = {
+  static const unsigned char aLen[121] = {
        7,   7,   5,   4,   6,   4,   5,   3,   6,   7,   3,   6,   6,
        7,   7,   3,   8,   2,   6,   5,   4,   4,   3,  10,   4,   6,
-      11,   2,   7,   5,   5,   9,   6,   9,   9,   7,  10,  10,   4,
-       6,   2,   3,   4,   9,   2,   6,   5,   6,   6,   5,   6,   5,
-       5,   7,   7,   7,   3,   4,   4,   7,   3,   6,   4,   7,   6,
-      12,   6,   9,   4,   6,   5,   4,   7,   6,   5,   6,   7,   5,
-       4,   5,   6,   5,   7,   3,   7,  13,   2,   2,   4,   6,   6,
-       8,   5,  17,  12,   7,   8,   8,   2,   4,   4,   4,   4,   4,
-       2,   2,   6,   5,   8,   5,   5,   8,   3,   5,   5,   6,   4,
-       9,   3,
+      11,   6,   2,   7,   5,   5,   9,   6,   9,   9,   7,  10,  10,
+       4,   6,   2,   3,   9,   4,   2,   6,   5,   6,   6,   5,   6,
+       5,   5,   7,   7,   7,   3,   2,   4,   4,   7,   3,   6,   4,
+       7,   6,  12,   6,   9,   4,   6,   5,   4,   7,   6,   5,   6,
+       7,   5,   4,   5,   6,   5,   7,   3,   7,  13,   2,   2,   4,
+       6,   6,   8,   5,  17,  12,   7,   8,   8,   2,   4,   4,   4,
+       4,   4,   2,   2,   6,   5,   8,   5,   5,   8,   3,   5,   5,
+       6,   4,   9,   3,
   };
-  static const unsigned short int aOffset[119] = {
+  static const unsigned short int aOffset[121] = {
        0,   2,   2,   8,   9,  14,  16,  20,  23,  25,  25,  29,  33,
       36,  41,  46,  48,  53,  54,  59,  62,  65,  67,  69,  78,  81,
-      86,  95,  96, 101, 105, 109, 117, 122, 128, 136, 142, 152, 159,
-     162, 162, 165, 167, 167, 171, 176, 179, 184, 189, 194, 197, 203,
-     206, 210, 217, 223, 223, 226, 229, 233, 234, 238, 244, 248, 255,
-     261, 273, 279, 288, 290, 296, 301, 303, 310, 315, 320, 326, 332,
-     337, 341, 344, 350, 354, 361, 363, 370, 372, 374, 383, 387, 393,
-     399, 407, 412, 412, 428, 435, 442, 443, 450, 454, 458, 462, 466,
-     469, 471, 473, 479, 483, 491, 495, 500, 508, 511, 516, 521, 527,
-     531, 536,
+      86,  91,  95,  96, 101, 105, 109, 117, 122, 128, 136, 142, 152,
+     159, 162, 162, 165, 167, 167, 171, 176, 179, 184, 189, 194, 197,
+     203, 206, 210, 217, 223, 223, 223, 226, 229, 233, 234, 238, 244,
+     248, 255, 261, 273, 279, 288, 290, 296, 301, 303, 310, 315, 320,
+     326, 332, 337, 341, 344, 350, 354, 361, 363, 370, 372, 374, 383,
+     387, 393, 399, 407, 412, 412, 428, 435, 442, 443, 450, 454, 458,
+     462, 466, 469, 471, 473, 479, 483, 491, 495, 500, 508, 511, 516,
+     521, 527, 531, 536,
   };
-  static const unsigned char aCode[119] = {
+  static const unsigned char aCode[121] = {
     TK_REINDEX,    TK_INDEXED,    TK_INDEX,      TK_DESC,       TK_ESCAPE,     
     TK_EACH,       TK_CHECK,      TK_KEY,        TK_BEFORE,     TK_FOREIGN,    
     TK_FOR,        TK_IGNORE,     TK_LIKE_KW,    TK_EXPLAIN,    TK_INSTEAD,    
     TK_ADD,        TK_DATABASE,   TK_AS,         TK_SELECT,     TK_TABLE,      
     TK_JOIN_KW,    TK_THEN,       TK_END,        TK_DEFERRABLE, TK_ELSE,       
-    TK_EXCEPT,     TK_TRANSACTION,TK_ON,         TK_JOIN_KW,    TK_ALTER,      
-    TK_RAISE,      TK_EXCLUSIVE,  TK_EXISTS,     TK_SAVEPOINT,  TK_INTERSECT,  
-    TK_TRIGGER,    TK_REFERENCES, TK_CONSTRAINT, TK_INTO,       TK_OFFSET,     
-    TK_OF,         TK_SET,        TK_TEMP,       TK_TEMP,       TK_OR,         
-    TK_UNIQUE,     TK_QUERY,      TK_ATTACH,     TK_HAVING,     TK_GROUP,      
-    TK_UPDATE,     TK_BEGIN,      TK_JOIN_KW,    TK_RELEASE,    TK_BETWEEN,    
-    TK_NOTNULL,    TK_NOT,        TK_NULL,       TK_LIKE_KW,    TK_CASCADE,    
-    TK_ASC,        TK_DELETE,     TK_CASE,       TK_COLLATE,    TK_CREATE,     
-    TK_CTIME_KW,   TK_DETACH,     TK_IMMEDIATE,  TK_JOIN,       TK_INSERT,     
-    TK_MATCH,      TK_PLAN,       TK_ANALYZE,    TK_PRAGMA,     TK_ABORT,      
-    TK_VALUES,     TK_VIRTUAL,    TK_LIMIT,      TK_WHEN,       TK_WHERE,      
-    TK_RENAME,     TK_AFTER,      TK_REPLACE,    TK_AND,        TK_DEFAULT,    
-    TK_AUTOINCR,   TK_TO,         TK_IN,         TK_CAST,       TK_COLUMNKW,   
-    TK_COMMIT,     TK_CONFLICT,   TK_JOIN_KW,    TK_CTIME_KW,   TK_CTIME_KW,   
-    TK_PRIMARY,    TK_DEFERRED,   TK_DISTINCT,   TK_IS,         TK_DROP,       
-    TK_FAIL,       TK_FROM,       TK_JOIN_KW,    TK_LIKE_KW,    TK_BY,         
-    TK_IF,         TK_ISNULL,     TK_ORDER,      TK_RESTRICT,   TK_JOIN_KW,    
-    TK_JOIN_KW,    TK_ROLLBACK,   TK_ROW,        TK_UNION,      TK_USING,      
-    TK_VACUUM,     TK_VIEW,       TK_INITIALLY,  TK_ALL,        
+    TK_EXCEPT,     TK_TRANSACTION,TK_ACTION,     TK_ON,         TK_JOIN_KW,    
+    TK_ALTER,      TK_RAISE,      TK_EXCLUSIVE,  TK_EXISTS,     TK_SAVEPOINT,  
+    TK_INTERSECT,  TK_TRIGGER,    TK_REFERENCES, TK_CONSTRAINT, TK_INTO,       
+    TK_OFFSET,     TK_OF,         TK_SET,        TK_TEMP,       TK_TEMP,       
+    TK_OR,         TK_UNIQUE,     TK_QUERY,      TK_ATTACH,     TK_HAVING,     
+    TK_GROUP,      TK_UPDATE,     TK_BEGIN,      TK_JOIN_KW,    TK_RELEASE,    
+    TK_BETWEEN,    TK_NOTNULL,    TK_NOT,        TK_NO,         TK_NULL,       
+    TK_LIKE_KW,    TK_CASCADE,    TK_ASC,        TK_DELETE,     TK_CASE,       
+    TK_COLLATE,    TK_CREATE,     TK_CTIME_KW,   TK_DETACH,     TK_IMMEDIATE,  
+    TK_JOIN,       TK_INSERT,     TK_MATCH,      TK_PLAN,       TK_ANALYZE,    
+    TK_PRAGMA,     TK_ABORT,      TK_VALUES,     TK_VIRTUAL,    TK_LIMIT,      
+    TK_WHEN,       TK_WHERE,      TK_RENAME,     TK_AFTER,      TK_REPLACE,    
+    TK_AND,        TK_DEFAULT,    TK_AUTOINCR,   TK_TO,         TK_IN,         
+    TK_CAST,       TK_COLUMNKW,   TK_COMMIT,     TK_CONFLICT,   TK_JOIN_KW,    
+    TK_CTIME_KW,   TK_CTIME_KW,   TK_PRIMARY,    TK_DEFERRED,   TK_DISTINCT,   
+    TK_IS,         TK_DROP,       TK_FAIL,       TK_FROM,       TK_JOIN_KW,    
+    TK_LIKE_KW,    TK_BY,         TK_IF,         TK_ISNULL,     TK_ORDER,      
+    TK_RESTRICT,   TK_JOIN_KW,    TK_JOIN_KW,    TK_ROLLBACK,   TK_ROW,        
+    TK_UNION,      TK_USING,      TK_VACUUM,     TK_VIEW,       TK_INITIALLY,  
+    TK_ALL,        
   };
   int h, i;
   if( n<2 ) return TK_ID;
@@ -86319,125 +110639,127 @@ static int keywordCode(const char *z, int n){
       n) % 127;
   for(i=((int)aHash[h])-1; i>=0; i=((int)aNext[i])-1){
     if( aLen[i]==n && sqlite3StrNICmp(&zText[aOffset[i]],z,n)==0 ){
-      testcase( i==0 ); /* TK_REINDEX */
-      testcase( i==1 ); /* TK_INDEXED */
-      testcase( i==2 ); /* TK_INDEX */
-      testcase( i==3 ); /* TK_DESC */
-      testcase( i==4 ); /* TK_ESCAPE */
-      testcase( i==5 ); /* TK_EACH */
-      testcase( i==6 ); /* TK_CHECK */
-      testcase( i==7 ); /* TK_KEY */
-      testcase( i==8 ); /* TK_BEFORE */
-      testcase( i==9 ); /* TK_FOREIGN */
-      testcase( i==10 ); /* TK_FOR */
-      testcase( i==11 ); /* TK_IGNORE */
-      testcase( i==12 ); /* TK_LIKE_KW */
-      testcase( i==13 ); /* TK_EXPLAIN */
-      testcase( i==14 ); /* TK_INSTEAD */
-      testcase( i==15 ); /* TK_ADD */
-      testcase( i==16 ); /* TK_DATABASE */
-      testcase( i==17 ); /* TK_AS */
-      testcase( i==18 ); /* TK_SELECT */
-      testcase( i==19 ); /* TK_TABLE */
-      testcase( i==20 ); /* TK_JOIN_KW */
-      testcase( i==21 ); /* TK_THEN */
-      testcase( i==22 ); /* TK_END */
-      testcase( i==23 ); /* TK_DEFERRABLE */
-      testcase( i==24 ); /* TK_ELSE */
-      testcase( i==25 ); /* TK_EXCEPT */
-      testcase( i==26 ); /* TK_TRANSACTION */
-      testcase( i==27 ); /* TK_ON */
-      testcase( i==28 ); /* TK_JOIN_KW */
-      testcase( i==29 ); /* TK_ALTER */
-      testcase( i==30 ); /* TK_RAISE */
-      testcase( i==31 ); /* TK_EXCLUSIVE */
-      testcase( i==32 ); /* TK_EXISTS */
-      testcase( i==33 ); /* TK_SAVEPOINT */
-      testcase( i==34 ); /* TK_INTERSECT */
-      testcase( i==35 ); /* TK_TRIGGER */
-      testcase( i==36 ); /* TK_REFERENCES */
-      testcase( i==37 ); /* TK_CONSTRAINT */
-      testcase( i==38 ); /* TK_INTO */
-      testcase( i==39 ); /* TK_OFFSET */
-      testcase( i==40 ); /* TK_OF */
-      testcase( i==41 ); /* TK_SET */
-      testcase( i==42 ); /* TK_TEMP */
-      testcase( i==43 ); /* TK_TEMP */
-      testcase( i==44 ); /* TK_OR */
-      testcase( i==45 ); /* TK_UNIQUE */
-      testcase( i==46 ); /* TK_QUERY */
-      testcase( i==47 ); /* TK_ATTACH */
-      testcase( i==48 ); /* TK_HAVING */
-      testcase( i==49 ); /* TK_GROUP */
-      testcase( i==50 ); /* TK_UPDATE */
-      testcase( i==51 ); /* TK_BEGIN */
-      testcase( i==52 ); /* TK_JOIN_KW */
-      testcase( i==53 ); /* TK_RELEASE */
-      testcase( i==54 ); /* TK_BETWEEN */
-      testcase( i==55 ); /* TK_NOTNULL */
-      testcase( i==56 ); /* TK_NOT */
-      testcase( i==57 ); /* TK_NULL */
-      testcase( i==58 ); /* TK_LIKE_KW */
-      testcase( i==59 ); /* TK_CASCADE */
-      testcase( i==60 ); /* TK_ASC */
-      testcase( i==61 ); /* TK_DELETE */
-      testcase( i==62 ); /* TK_CASE */
-      testcase( i==63 ); /* TK_COLLATE */
-      testcase( i==64 ); /* TK_CREATE */
-      testcase( i==65 ); /* TK_CTIME_KW */
-      testcase( i==66 ); /* TK_DETACH */
-      testcase( i==67 ); /* TK_IMMEDIATE */
-      testcase( i==68 ); /* TK_JOIN */
-      testcase( i==69 ); /* TK_INSERT */
-      testcase( i==70 ); /* TK_MATCH */
-      testcase( i==71 ); /* TK_PLAN */
-      testcase( i==72 ); /* TK_ANALYZE */
-      testcase( i==73 ); /* TK_PRAGMA */
-      testcase( i==74 ); /* TK_ABORT */
-      testcase( i==75 ); /* TK_VALUES */
-      testcase( i==76 ); /* TK_VIRTUAL */
-      testcase( i==77 ); /* TK_LIMIT */
-      testcase( i==78 ); /* TK_WHEN */
-      testcase( i==79 ); /* TK_WHERE */
-      testcase( i==80 ); /* TK_RENAME */
-      testcase( i==81 ); /* TK_AFTER */
-      testcase( i==82 ); /* TK_REPLACE */
-      testcase( i==83 ); /* TK_AND */
-      testcase( i==84 ); /* TK_DEFAULT */
-      testcase( i==85 ); /* TK_AUTOINCR */
-      testcase( i==86 ); /* TK_TO */
-      testcase( i==87 ); /* TK_IN */
-      testcase( i==88 ); /* TK_CAST */
-      testcase( i==89 ); /* TK_COLUMNKW */
-      testcase( i==90 ); /* TK_COMMIT */
-      testcase( i==91 ); /* TK_CONFLICT */
-      testcase( i==92 ); /* TK_JOIN_KW */
-      testcase( i==93 ); /* TK_CTIME_KW */
-      testcase( i==94 ); /* TK_CTIME_KW */
-      testcase( i==95 ); /* TK_PRIMARY */
-      testcase( i==96 ); /* TK_DEFERRED */
-      testcase( i==97 ); /* TK_DISTINCT */
-      testcase( i==98 ); /* TK_IS */
-      testcase( i==99 ); /* TK_DROP */
-      testcase( i==100 ); /* TK_FAIL */
-      testcase( i==101 ); /* TK_FROM */
-      testcase( i==102 ); /* TK_JOIN_KW */
-      testcase( i==103 ); /* TK_LIKE_KW */
-      testcase( i==104 ); /* TK_BY */
-      testcase( i==105 ); /* TK_IF */
-      testcase( i==106 ); /* TK_ISNULL */
-      testcase( i==107 ); /* TK_ORDER */
-      testcase( i==108 ); /* TK_RESTRICT */
-      testcase( i==109 ); /* TK_JOIN_KW */
-      testcase( i==110 ); /* TK_JOIN_KW */
-      testcase( i==111 ); /* TK_ROLLBACK */
-      testcase( i==112 ); /* TK_ROW */
-      testcase( i==113 ); /* TK_UNION */
-      testcase( i==114 ); /* TK_USING */
-      testcase( i==115 ); /* TK_VACUUM */
-      testcase( i==116 ); /* TK_VIEW */
-      testcase( i==117 ); /* TK_INITIALLY */
-      testcase( i==118 ); /* TK_ALL */
+      testcase( i==0 ); /* REINDEX */
+      testcase( i==1 ); /* INDEXED */
+      testcase( i==2 ); /* INDEX */
+      testcase( i==3 ); /* DESC */
+      testcase( i==4 ); /* ESCAPE */
+      testcase( i==5 ); /* EACH */
+      testcase( i==6 ); /* CHECK */
+      testcase( i==7 ); /* KEY */
+      testcase( i==8 ); /* BEFORE */
+      testcase( i==9 ); /* FOREIGN */
+      testcase( i==10 ); /* FOR */
+      testcase( i==11 ); /* IGNORE */
+      testcase( i==12 ); /* REGEXP */
+      testcase( i==13 ); /* EXPLAIN */
+      testcase( i==14 ); /* INSTEAD */
+      testcase( i==15 ); /* ADD */
+      testcase( i==16 ); /* DATABASE */
+      testcase( i==17 ); /* AS */
+      testcase( i==18 ); /* SELECT */
+      testcase( i==19 ); /* TABLE */
+      testcase( i==20 ); /* LEFT */
+      testcase( i==21 ); /* THEN */
+      testcase( i==22 ); /* END */
+      testcase( i==23 ); /* DEFERRABLE */
+      testcase( i==24 ); /* ELSE */
+      testcase( i==25 ); /* EXCEPT */
+      testcase( i==26 ); /* TRANSACTION */
+      testcase( i==27 ); /* ACTION */
+      testcase( i==28 ); /* ON */
+      testcase( i==29 ); /* NATURAL */
+      testcase( i==30 ); /* ALTER */
+      testcase( i==31 ); /* RAISE */
+      testcase( i==32 ); /* EXCLUSIVE */
+      testcase( i==33 ); /* EXISTS */
+      testcase( i==34 ); /* SAVEPOINT */
+      testcase( i==35 ); /* INTERSECT */
+      testcase( i==36 ); /* TRIGGER */
+      testcase( i==37 ); /* REFERENCES */
+      testcase( i==38 ); /* CONSTRAINT */
+      testcase( i==39 ); /* INTO */
+      testcase( i==40 ); /* OFFSET */
+      testcase( i==41 ); /* OF */
+      testcase( i==42 ); /* SET */
+      testcase( i==43 ); /* TEMPORARY */
+      testcase( i==44 ); /* TEMP */
+      testcase( i==45 ); /* OR */
+      testcase( i==46 ); /* UNIQUE */
+      testcase( i==47 ); /* QUERY */
+      testcase( i==48 ); /* ATTACH */
+      testcase( i==49 ); /* HAVING */
+      testcase( i==50 ); /* GROUP */
+      testcase( i==51 ); /* UPDATE */
+      testcase( i==52 ); /* BEGIN */
+      testcase( i==53 ); /* INNER */
+      testcase( i==54 ); /* RELEASE */
+      testcase( i==55 ); /* BETWEEN */
+      testcase( i==56 ); /* NOTNULL */
+      testcase( i==57 ); /* NOT */
+      testcase( i==58 ); /* NO */
+      testcase( i==59 ); /* NULL */
+      testcase( i==60 ); /* LIKE */
+      testcase( i==61 ); /* CASCADE */
+      testcase( i==62 ); /* ASC */
+      testcase( i==63 ); /* DELETE */
+      testcase( i==64 ); /* CASE */
+      testcase( i==65 ); /* COLLATE */
+      testcase( i==66 ); /* CREATE */
+      testcase( i==67 ); /* CURRENT_DATE */
+      testcase( i==68 ); /* DETACH */
+      testcase( i==69 ); /* IMMEDIATE */
+      testcase( i==70 ); /* JOIN */
+      testcase( i==71 ); /* INSERT */
+      testcase( i==72 ); /* MATCH */
+      testcase( i==73 ); /* PLAN */
+      testcase( i==74 ); /* ANALYZE */
+      testcase( i==75 ); /* PRAGMA */
+      testcase( i==76 ); /* ABORT */
+      testcase( i==77 ); /* VALUES */
+      testcase( i==78 ); /* VIRTUAL */
+      testcase( i==79 ); /* LIMIT */
+      testcase( i==80 ); /* WHEN */
+      testcase( i==81 ); /* WHERE */
+      testcase( i==82 ); /* RENAME */
+      testcase( i==83 ); /* AFTER */
+      testcase( i==84 ); /* REPLACE */
+      testcase( i==85 ); /* AND */
+      testcase( i==86 ); /* DEFAULT */
+      testcase( i==87 ); /* AUTOINCREMENT */
+      testcase( i==88 ); /* TO */
+      testcase( i==89 ); /* IN */
+      testcase( i==90 ); /* CAST */
+      testcase( i==91 ); /* COLUMN */
+      testcase( i==92 ); /* COMMIT */
+      testcase( i==93 ); /* CONFLICT */
+      testcase( i==94 ); /* CROSS */
+      testcase( i==95 ); /* CURRENT_TIMESTAMP */
+      testcase( i==96 ); /* CURRENT_TIME */
+      testcase( i==97 ); /* PRIMARY */
+      testcase( i==98 ); /* DEFERRED */
+      testcase( i==99 ); /* DISTINCT */
+      testcase( i==100 ); /* IS */
+      testcase( i==101 ); /* DROP */
+      testcase( i==102 ); /* FAIL */
+      testcase( i==103 ); /* FROM */
+      testcase( i==104 ); /* FULL */
+      testcase( i==105 ); /* GLOB */
+      testcase( i==106 ); /* BY */
+      testcase( i==107 ); /* IF */
+      testcase( i==108 ); /* ISNULL */
+      testcase( i==109 ); /* ORDER */
+      testcase( i==110 ); /* RESTRICT */
+      testcase( i==111 ); /* OUTER */
+      testcase( i==112 ); /* RIGHT */
+      testcase( i==113 ); /* ROLLBACK */
+      testcase( i==114 ); /* ROW */
+      testcase( i==115 ); /* UNION */
+      testcase( i==116 ); /* USING */
+      testcase( i==117 ); /* VACUUM */
+      testcase( i==118 ); /* VIEW */
+      testcase( i==119 ); /* INITIALLY */
+      testcase( i==120 ); /* ALL */
       return aCode[i];
     }
   }
@@ -86446,6 +110768,7 @@ static int keywordCode(const char *z, int n){
 SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char *z, int n){
   return keywordCode((char*)z, n);
 }
+#define SQLITE_N_KEYWORD 121
 
 /************** End of keywordhash.h *****************************************/
 /************** Continuing where we left off in tokenize.c *******************/
@@ -86468,16 +110791,7 @@ SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char *z, int n){
 ** But the feature is undocumented.
 */
 #ifdef SQLITE_ASCII
-SQLITE_PRIVATE const char sqlite3IsAsciiIdChar[] = {
-/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
-    0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
-};
-#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && sqlite3IsAsciiIdChar[c-0x20]))
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
 #endif
 #ifdef SQLITE_EBCDIC
 SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[] = {
@@ -86507,14 +110821,20 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
   int i, c;
   switch( *z ){
     case ' ': case '\t': case '\n': case '\f': case '\r': {
-      for(i=1; isspace(z[i]); i++){}
+      testcase( z[0]==' ' );
+      testcase( z[0]=='\t' );
+      testcase( z[0]=='\n' );
+      testcase( z[0]=='\f' );
+      testcase( z[0]=='\r' );
+      for(i=1; sqlite3Isspace(z[i]); i++){}
       *tokenType = TK_SPACE;
       return i;
     }
     case '-': {
       if( z[1]=='-' ){
+        /* IMP: R-50417-27976 -- syntax diagram for comments */
         for(i=2; (c=z[i])!=0 && c!='\n'; i++){}
-        *tokenType = TK_SPACE;
+        *tokenType = TK_SPACE;   /* IMP: R-22934-25134 */
         return i;
       }
       *tokenType = TK_MINUS;
@@ -86545,9 +110865,10 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
         *tokenType = TK_SLASH;
         return 1;
       }
+      /* IMP: R-50417-27976 -- syntax diagram for comments */
       for(i=3, c=z[2]; (c!='*' || z[i]!='/') && (c=z[i])!=0; i++){}
       if( c ) i++;
-      *tokenType = TK_SPACE;
+      *tokenType = TK_SPACE;   /* IMP: R-22934-25134 */
       return i;
     }
     case '%': {
@@ -86619,6 +110940,9 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
     case '\'':
     case '"': {
       int delim = z[0];
+      testcase( delim=='`' );
+      testcase( delim=='\'' );
+      testcase( delim=='"' );
       for(i=1; (c=z[i])!=0; i++){
         if( c==delim ){
           if( z[i+1]==delim ){
@@ -86641,7 +110965,7 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
     }
     case '.': {
 #ifndef SQLITE_OMIT_FLOATING_POINT
-      if( !isdigit(z[1]) )
+      if( !sqlite3Isdigit(z[1]) )
 #endif
       {
         *tokenType = TK_DOT;
@@ -86652,21 +110976,25 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
     }
     case '0': case '1': case '2': case '3': case '4':
     case '5': case '6': case '7': case '8': case '9': {
+      testcase( z[0]=='0' );  testcase( z[0]=='1' );  testcase( z[0]=='2' );
+      testcase( z[0]=='3' );  testcase( z[0]=='4' );  testcase( z[0]=='5' );
+      testcase( z[0]=='6' );  testcase( z[0]=='7' );  testcase( z[0]=='8' );
+      testcase( z[0]=='9' );
       *tokenType = TK_INTEGER;
-      for(i=0; isdigit(z[i]); i++){}
+      for(i=0; sqlite3Isdigit(z[i]); i++){}
 #ifndef SQLITE_OMIT_FLOATING_POINT
       if( z[i]=='.' ){
         i++;
-        while( isdigit(z[i]) ){ i++; }
+        while( sqlite3Isdigit(z[i]) ){ i++; }
         *tokenType = TK_FLOAT;
       }
       if( (z[i]=='e' || z[i]=='E') &&
-           ( isdigit(z[i+1]) 
-            || ((z[i+1]=='+' || z[i+1]=='-') && isdigit(z[i+2]))
+           ( sqlite3Isdigit(z[i+1]) 
+            || ((z[i+1]=='+' || z[i+1]=='-') && sqlite3Isdigit(z[i+2]))
            )
       ){
         i += 2;
-        while( isdigit(z[i]) ){ i++; }
+        while( sqlite3Isdigit(z[i]) ){ i++; }
         *tokenType = TK_FLOAT;
       }
 #endif
@@ -86683,11 +111011,11 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
     }
     case '?': {
       *tokenType = TK_VARIABLE;
-      for(i=1; isdigit(z[i]); i++){}
+      for(i=1; sqlite3Isdigit(z[i]); i++){}
       return i;
     }
     case '#': {
-      for(i=1; isdigit(z[i]); i++){}
+      for(i=1; sqlite3Isdigit(z[i]); i++){}
       if( i>1 ){
         /* Parameters of the form #NNN (where NNN is a number) are used
         ** internally by sqlite3NestedParse.  */
@@ -86703,6 +111031,7 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
     case '@':  /* For compatibility with MS SQL Server */
     case ':': {
       int n = 0;
+      testcase( z[0]=='$' );  testcase( z[0]=='@' );  testcase( z[0]==':' );
       *tokenType = TK_VARIABLE;
       for(i=1; (c=z[i])!=0; i++){
         if( IdChar(c) ){
@@ -86711,7 +111040,7 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
         }else if( c=='(' && n>0 ){
           do{
             i++;
-          }while( (c=z[i])!=0 && !isspace(c) && c!=')' );
+          }while( (c=z[i])!=0 && !sqlite3Isspace(c) && c!=')' );
           if( c==')' ){
             i++;
           }else{
@@ -86730,15 +111059,15 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
     }
 #ifndef SQLITE_OMIT_BLOB_LITERAL
     case 'x': case 'X': {
+      testcase( z[0]=='x' ); testcase( z[0]=='X' );
       if( z[1]=='\'' ){
         *tokenType = TK_BLOB;
-        for(i=2; (c=z[i])!=0 && c!='\''; i++){
-          if( !isxdigit(c) ){
-            *tokenType = TK_ILLEGAL;
-          }
+        for(i=2; sqlite3Isxdigit(z[i]); i++){}
+        if( z[i]!='\'' || i%2 ){
+          *tokenType = TK_ILLEGAL;
+          while( z[i] && z[i]!='\'' ){ i++; }
         }
-        if( i%2 || !c ) *tokenType = TK_ILLEGAL;
-        if( c ) i++;
+        if( z[i] ) i++;
         return i;
       }
       /* Otherwise fall through to the next case */
@@ -86765,19 +111094,22 @@ SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
 ** error message.
 */
 SQLITE_PRIVATE int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
-  int nErr = 0;
-  int i;
-  void *pEngine;
-  int tokenType;
-  int lastTokenParsed = -1;
-  sqlite3 *db = pParse->db;
-  int mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+  int nErr = 0;                   /* Number of errors encountered */
+  int i;                          /* Loop counter */
+  void *pEngine;                  /* The LEMON-generated LALR(1) parser */
+  int tokenType;                  /* type of the next token */
+  int lastTokenParsed = -1;       /* type of the previous token */
+  u8 enableLookaside;             /* Saved value of db->lookaside.bEnabled */
+  sqlite3 *db = pParse->db;       /* The database connection */
+  int mxSqlLen;                   /* Max length of an SQL string */
 
+
+  mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
   if( db->activeVdbeCnt==0 ){
     db->u1.isInterrupted = 0;
   }
   pParse->rc = SQLITE_OK;
-  pParse->zTail = pParse->zSql = zSql;
+  pParse->zTail = zSql;
   i = 0;
   assert( pzErrMsg!=0 );
   pEngine = sqlite3ParserAlloc((void*(*)(size_t))sqlite3Malloc);
@@ -86785,17 +111117,16 @@ SQLITE_PRIVATE int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzEr
     db->mallocFailed = 1;
     return SQLITE_NOMEM;
   }
-  assert( pParse->sLastToken.dyn==0 );
   assert( pParse->pNewTable==0 );
   assert( pParse->pNewTrigger==0 );
   assert( pParse->nVar==0 );
-  assert( pParse->nVarExpr==0 );
-  assert( pParse->nVarExprAlloc==0 );
-  assert( pParse->apVarExpr==0 );
+  assert( pParse->nzVar==0 );
+  assert( pParse->azVar==0 );
+  enableLookaside = db->lookaside.bEnabled;
+  if( db->lookaside.pStart ) db->lookaside.bEnabled = 1;
   while( !db->mallocFailed && zSql[i]!=0 ){
     assert( i>=0 );
-    pParse->sLastToken.z = (u8*)&zSql[i];
-    assert( pParse->sLastToken.dyn==0 );
+    pParse->sLastToken.z = &zSql[i];
     pParse->sLastToken.n = sqlite3GetToken((unsigned char*)&zSql[i],&tokenType);
     i += pParse->sLastToken.n;
     if( i>mxSqlLen ){
@@ -86805,8 +111136,8 @@ SQLITE_PRIVATE int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzEr
     switch( tokenType ){
       case TK_SPACE: {
         if( db->u1.isInterrupted ){
+          sqlite3ErrorMsg(pParse, "interrupt");
           pParse->rc = SQLITE_INTERRUPT;
-          sqlite3SetString(pzErrMsg, db, "interrupt");
           goto abort_parse;
         }
         break;
@@ -86846,18 +111177,17 @@ abort_parse:
   );
 #endif /* YYDEBUG */
   sqlite3ParserFree(pEngine, sqlite3_free);
+  db->lookaside.bEnabled = enableLookaside;
   if( db->mallocFailed ){
     pParse->rc = SQLITE_NOMEM;
   }
   if( pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE && pParse->zErrMsg==0 ){
     sqlite3SetString(&pParse->zErrMsg, db, "%s", sqlite3ErrStr(pParse->rc));
   }
+  assert( pzErrMsg!=0 );
   if( pParse->zErrMsg ){
-    if( *pzErrMsg==0 ){
-      *pzErrMsg = pParse->zErrMsg;
-    }else{
-      sqlite3DbFree(db, pParse->zErrMsg);
-    }
+    *pzErrMsg = pParse->zErrMsg;
+    sqlite3_log(pParse->rc, "%s", *pzErrMsg);
     pParse->zErrMsg = 0;
     nErr++;
   }
@@ -86873,7 +111203,7 @@ abort_parse:
   }
 #endif
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-  sqlite3DbFree(db, pParse->apVtabLock);
+  sqlite3_free(pParse->apVtabLock);
 #endif
 
   if( !IN_DECLARE_VTAB ){
@@ -86881,18 +111211,24 @@ abort_parse:
     ** structure built up in pParse->pNewTable. The calling code (see vtab.c)
     ** will take responsibility for freeing the Table structure.
     */
-    sqlite3DeleteTable(pParse->pNewTable);
+    sqlite3DeleteTable(db, pParse->pNewTable);
   }
 
   sqlite3DeleteTrigger(db, pParse->pNewTrigger);
-  sqlite3DbFree(db, pParse->apVarExpr);
+  for(i=pParse->nzVar-1; i>=0; i--) sqlite3DbFree(db, pParse->azVar[i]);
+  sqlite3DbFree(db, pParse->azVar);
   sqlite3DbFree(db, pParse->aAlias);
+  while( pParse->pAinc ){
+    AutoincInfo *p = pParse->pAinc;
+    pParse->pAinc = p->pNext;
+    sqlite3DbFree(db, p);
+  }
   while( pParse->pZombieTab ){
     Table *p = pParse->pZombieTab;
     pParse->pZombieTab = p->pNextZombie;
-    sqlite3DeleteTable(p);
+    sqlite3DeleteTable(db, p);
   }
-  if( nErr>0 && (pParse->rc==SQLITE_OK || pParse->rc==SQLITE_DONE) ){
+  if( nErr>0 && pParse->rc==SQLITE_OK ){
     pParse->rc = SQLITE_ERROR;
   }
   return nErr;
@@ -86917,8 +111253,6 @@ abort_parse:
 ** This code used to be part of the tokenizer.c source file.  But by
 ** separating it out, the code will be automatically omitted from
 ** static links that do not use it.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 #ifndef SQLITE_OMIT_COMPLETE
 
@@ -86927,8 +111261,7 @@ abort_parse:
 */
 #ifndef SQLITE_AMALGAMATION
 #ifdef SQLITE_ASCII
-SQLITE_PRIVATE const char sqlite3IsAsciiIdChar[];
-#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && sqlite3IsAsciiIdChar[c-0x20]))
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
 #endif
 #ifdef SQLITE_EBCDIC
 SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
@@ -86944,11 +111277,13 @@ SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
 #define tkSEMI    0
 #define tkWS      1
 #define tkOTHER   2
+#ifndef SQLITE_OMIT_TRIGGER
 #define tkEXPLAIN 3
 #define tkCREATE  4
 #define tkTEMP    5
 #define tkTRIGGER 6
 #define tkEND     7
+#endif
 
 /*
 ** Return TRUE if the given SQL string ends in a semicolon.
@@ -86957,36 +111292,38 @@ SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
 ** Whenever the CREATE TRIGGER keywords are seen, the statement
 ** must end with ";END;".
 **
-** This implementation uses a state machine with 7 states:
+** This implementation uses a state machine with 8 states:
 **
-**   (0) START     At the beginning or end of an SQL statement.  This routine
+**   (0) INVALID   We have not yet seen a non-whitespace character.
+**
+**   (1) START     At the beginning or end of an SQL statement.  This routine
 **                 returns 1 if it ends in the START state and 0 if it ends
 **                 in any other state.
 **
-**   (1) NORMAL    We are in the middle of statement which ends with a single
+**   (2) NORMAL    We are in the middle of statement which ends with a single
 **                 semicolon.
 **
-**   (2) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of 
+**   (3) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of 
 **                 a statement.
 **
-**   (3) CREATE    The keyword CREATE has been seen at the beginning of a
+**   (4) CREATE    The keyword CREATE has been seen at the beginning of a
 **                 statement, possibly preceeded by EXPLAIN and/or followed by
 **                 TEMP or TEMPORARY
 **
-**   (4) TRIGGER   We are in the middle of a trigger definition that must be
+**   (5) TRIGGER   We are in the middle of a trigger definition that must be
 **                 ended by a semicolon, the keyword END, and another semicolon.
 **
-**   (5) SEMI      We've seen the first semicolon in the ";END;" that occurs at
+**   (6) SEMI      We've seen the first semicolon in the ";END;" that occurs at
 **                 the end of a trigger definition.
 **
-**   (6) END       We've seen the ";END" of the ";END;" that occurs at the end
+**   (7) END       We've seen the ";END" of the ";END;" that occurs at the end
 **                 of a trigger difinition.
 **
 ** Transitions between states above are determined by tokens extracted
 ** from the input.  The following tokens are significant:
 **
 **   (0) tkSEMI      A semicolon.
-**   (1) tkWS        Whitespace
+**   (1) tkWS        Whitespace.
 **   (2) tkOTHER     Any other SQL token.
 **   (3) tkEXPLAIN   The "explain" keyword.
 **   (4) tkCREATE    The "create" keyword.
@@ -86995,6 +111332,7 @@ SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
 **   (7) tkEND       The "end" keyword.
 **
 ** Whitespace never causes a state transition and is always ignored.
+** This means that a SQL string of all whitespace is invalid.
 **
 ** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed
 ** to recognize the end of a trigger can be omitted.  All we have to do
@@ -87008,26 +111346,28 @@ SQLITE_API int sqlite3_complete(const char *zSql){
   /* A complex statement machine used to detect the end of a CREATE TRIGGER
   ** statement.  This is the normal case.
   */
-  static const u8 trans[7][8] = {
+  static const u8 trans[8][8] = {
                      /* Token:                                                */
-     /* State:       **  SEMI  WS  OTHER EXPLAIN  CREATE  TEMP  TRIGGER  END  */
-     /* 0   START: */ {    0,  0,     1,      2,      3,    1,       1,   1,  },
-     /* 1  NORMAL: */ {    0,  1,     1,      1,      1,    1,       1,   1,  },
-     /* 2 EXPLAIN: */ {    0,  2,     1,      1,      3,    1,       1,   1,  },
-     /* 3  CREATE: */ {    0,  3,     1,      1,      1,    3,       4,   1,  },
-     /* 4 TRIGGER: */ {    5,  4,     4,      4,      4,    4,       4,   4,  },
-     /* 5    SEMI: */ {    5,  5,     4,      4,      4,    4,       4,   6,  },
-     /* 6     END: */ {    0,  6,     4,      4,      4,    4,       4,   4,  },
+     /* State:       **  SEMI  WS  OTHER  EXPLAIN  CREATE  TEMP  TRIGGER  END */
+     /* 0 INVALID: */ {    1,  0,     2,       3,      4,    2,       2,   2, },
+     /* 1   START: */ {    1,  1,     2,       3,      4,    2,       2,   2, },
+     /* 2  NORMAL: */ {    1,  2,     2,       2,      2,    2,       2,   2, },
+     /* 3 EXPLAIN: */ {    1,  3,     3,       2,      4,    2,       2,   2, },
+     /* 4  CREATE: */ {    1,  4,     2,       2,      2,    4,       5,   2, },
+     /* 5 TRIGGER: */ {    6,  5,     5,       5,      5,    5,       5,   5, },
+     /* 6    SEMI: */ {    6,  6,     5,       5,      5,    5,       5,   7, },
+     /* 7     END: */ {    1,  7,     5,       5,      5,    5,       5,   5, },
   };
 #else
-  /* If triggers are not suppored by this compile then the statement machine
+  /* If triggers are not supported by this compile then the statement machine
   ** used to detect the end of a statement is much simplier
   */
-  static const u8 trans[2][3] = {
+  static const u8 trans[3][3] = {
                      /* Token:           */
      /* State:       **  SEMI  WS  OTHER */
-     /* 0   START: */ {    0,  0,     1, },
-     /* 1  NORMAL: */ {    0,  1,     1, },
+     /* 0 INVALID: */ {    1,  0,     2, },
+     /* 1   START: */ {    1,  1,     2, },
+     /* 2  NORMAL: */ {    1,  2,     2, },
   };
 #endif /* SQLITE_OMIT_TRIGGER */
 
@@ -87063,7 +111403,7 @@ SQLITE_API int sqlite3_complete(const char *zSql){
           break;
         }
         while( *zSql && *zSql!='\n' ){ zSql++; }
-        if( *zSql==0 ) return state==0;
+        if( *zSql==0 ) return state==1;
         token = tkWS;
         break;
       }
@@ -87085,7 +111425,9 @@ SQLITE_API int sqlite3_complete(const char *zSql){
         break;
       }
       default: {
-        int c;
+#ifdef SQLITE_EBCDIC
+        unsigned char c;
+#endif
         if( IdChar((u8)*zSql) ){
           /* Keywords and unquoted identifiers */
           int nId;
@@ -87145,7 +111487,7 @@ SQLITE_API int sqlite3_complete(const char *zSql){
     state = trans[state][token];
     zSql++;
   }
-  return state==0;
+  return state==1;
 }
 
 #ifndef SQLITE_OMIT_UTF16
@@ -87194,8 +111536,6 @@ SQLITE_API int sqlite3_complete16(const void *zSql){
 ** implement the programmer interface to the library.  Routines in
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
-**
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
 
 #ifdef SQLITE_ENABLE_FTS3
@@ -87296,14 +111636,33 @@ SQLITE_PRIVATE int sqlite3IcuInit(sqlite3 *db);
 /************** Continuing where we left off in main.c ***********************/
 #endif
 
-/*
-** The version of the library
-*/
 #ifndef SQLITE_AMALGAMATION
+/* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
+** contains the text of SQLITE_VERSION macro. 
+*/
 SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
 #endif
+
+/* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
+** a pointer to the to the sqlite3_version[] string constant. 
+*/
 SQLITE_API const char *sqlite3_libversion(void){ return sqlite3_version; }
+
+/* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
+** pointer to a string constant whose value is the same as the
+** SQLITE_SOURCE_ID C preprocessor macro. 
+*/
+SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
+
+/* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
+** returns an integer equal to SQLITE_VERSION_NUMBER.
+*/
 SQLITE_API int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
+
+/* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
+** zero if and only if SQLite was compiled with mutexing code omitted due to
+** the SQLITE_THREADSAFE compile-time option being set to 0.
+*/
 SQLITE_API int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
 
 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
@@ -87325,6 +111684,15 @@ SQLITE_PRIVATE void (*sqlite3IoTrace)(const char*, ...) = 0;
 */
 SQLITE_API char *sqlite3_temp_directory = 0;
 
+/*
+** If the following global variable points to a string which is the
+** name of a directory, then that directory will be used to store
+** all database files specified with a relative pathname.
+**
+** See also the "PRAGMA data_store_directory" SQL command.
+*/
+SQLITE_API char *sqlite3_data_directory = 0;
+
 /*
 ** Initialize SQLite.  
 **
@@ -87357,7 +111725,7 @@ SQLITE_API char *sqlite3_temp_directory = 0;
 **       without blocking.
 */
 SQLITE_API int sqlite3_initialize(void){
-  sqlite3_mutex *pMaster;                      /* The main static mutex */
+  MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
   int rc;                                      /* Result code */
 
 #ifdef SQLITE_OMIT_WSD
@@ -87391,15 +111759,17 @@ SQLITE_API int sqlite3_initialize(void){
   ** malloc subsystem - this implies that the allocation of a static
   ** mutex must not require support from the malloc subsystem.
   */
-  pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
+  MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
   sqlite3_mutex_enter(pMaster);
+  sqlite3GlobalConfig.isMutexInit = 1;
   if( !sqlite3GlobalConfig.isMallocInit ){
     rc = sqlite3MallocInit();
   }
   if( rc==SQLITE_OK ){
     sqlite3GlobalConfig.isMallocInit = 1;
     if( !sqlite3GlobalConfig.pInitMutex ){
-      sqlite3GlobalConfig.pInitMutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
+      sqlite3GlobalConfig.pInitMutex =
+           sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
         rc = SQLITE_NOMEM;
       }
@@ -87410,10 +111780,9 @@ SQLITE_API int sqlite3_initialize(void){
   }
   sqlite3_mutex_leave(pMaster);
 
-  /* If unable to initialize the malloc subsystem, then return early.
-  ** There is little hope of getting SQLite to run if the malloc
-  ** subsystem cannot be initialized.
-  */
+  /* If rc is not SQLITE_OK at this point, then either the malloc
+  ** subsystem could not be initialized or the system failed to allocate
+  ** the pInitMutex mutex. Return an error in either case.  */
   if( rc!=SQLITE_OK ){
     return rc;
   }
@@ -87423,6 +111792,13 @@ SQLITE_API int sqlite3_initialize(void){
   ** sqlite3_initialize().  The recursive calls normally come through
   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
   ** recursive calls might also be possible.
+  **
+  ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
+  ** to the xInit method, so the xInit method need not be threadsafe.
+  **
+  ** The following mutex is what serializes access to the appdef pcache xInit
+  ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
+  ** call to sqlite3PcacheInitialize().
   */
   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
@@ -87430,14 +111806,19 @@ SQLITE_API int sqlite3_initialize(void){
     sqlite3GlobalConfig.inProgress = 1;
     memset(pHash, 0, sizeof(sqlite3GlobalFunctions));
     sqlite3RegisterGlobalFunctions();
-    rc = sqlite3_os_init();
-    if( rc==SQLITE_OK ){
+    if( sqlite3GlobalConfig.isPCacheInit==0 ){
       rc = sqlite3PcacheInitialize();
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3GlobalConfig.isPCacheInit = 1;
+      rc = sqlite3OsInit();
+    }
+    if( rc==SQLITE_OK ){
       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage, 
           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
+      sqlite3GlobalConfig.isInit = 1;
     }
     sqlite3GlobalConfig.inProgress = 0;
-    sqlite3GlobalConfig.isInit = (rc==SQLITE_OK ? 1 : 0);
   }
   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
 
@@ -87459,6 +111840,7 @@ SQLITE_API int sqlite3_initialize(void){
   ** reason.  So we run it once during initialization.
   */
 #ifndef NDEBUG
+#ifndef SQLITE_OMIT_FLOATING_POINT
   /* This section of code's only "output" is via assert() statements. */
   if ( rc==SQLITE_OK ){
     u64 x = (((u64)1)<<63)-1;
@@ -87469,6 +111851,17 @@ SQLITE_API int sqlite3_initialize(void){
     assert( sqlite3IsNaN(y) );
   }
 #endif
+#endif
+
+  /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
+  ** compile-time option.
+  */
+#ifdef SQLITE_EXTRA_INIT
+  if( rc==SQLITE_OK && sqlite3GlobalConfig.isInit ){
+    int SQLITE_EXTRA_INIT(const char*);
+    rc = SQLITE_EXTRA_INIT(0);
+  }
+#endif
 
   return rc;
 }
@@ -87477,17 +111870,45 @@ SQLITE_API int sqlite3_initialize(void){
 ** Undo the effects of sqlite3_initialize().  Must not be called while
 ** there are outstanding database connections or memory allocations or
 ** while any part of SQLite is otherwise in use in any thread.  This
-** routine is not threadsafe.  Not by a long shot.
+** routine is not threadsafe.  But it is safe to invoke this routine
+** on when SQLite is already shut down.  If SQLite is already shut down
+** when this routine is invoked, then this routine is a harmless no-op.
 */
 SQLITE_API int sqlite3_shutdown(void){
-  sqlite3GlobalConfig.isMallocInit = 0;
-  sqlite3PcacheShutdown();
   if( sqlite3GlobalConfig.isInit ){
+#ifdef SQLITE_EXTRA_SHUTDOWN
+    void SQLITE_EXTRA_SHUTDOWN(void);
+    SQLITE_EXTRA_SHUTDOWN();
+#endif
     sqlite3_os_end();
+    sqlite3_reset_auto_extension();
+    sqlite3GlobalConfig.isInit = 0;
   }
-  sqlite3MallocEnd();
-  sqlite3MutexEnd();
-  sqlite3GlobalConfig.isInit = 0;
+  if( sqlite3GlobalConfig.isPCacheInit ){
+    sqlite3PcacheShutdown();
+    sqlite3GlobalConfig.isPCacheInit = 0;
+  }
+  if( sqlite3GlobalConfig.isMallocInit ){
+    sqlite3MallocEnd();
+    sqlite3GlobalConfig.isMallocInit = 0;
+
+#ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
+    /* The heap subsystem has now been shutdown and these values are supposed
+    ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
+    ** which would rely on that heap subsystem; therefore, make sure these
+    ** values cannot refer to heap memory that was just invalidated when the
+    ** heap subsystem was shutdown.  This is only done if the current call to
+    ** this function resulted in the heap subsystem actually being shutdown.
+    */
+    sqlite3_data_directory = 0;
+    sqlite3_temp_directory = 0;
+#endif
+  }
+  if( sqlite3GlobalConfig.isMutexInit ){
+    sqlite3MutexEnd();
+    sqlite3GlobalConfig.isMutexInit = 0;
+  }
+
   return SQLITE_OK;
 }
 
@@ -87506,7 +111927,7 @@ SQLITE_API int sqlite3_config(int op, ...){
 
   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
   ** the SQLite library is in use. */
-  if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE;
+  if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
 
   va_start(ap, op);
   switch( op ){
@@ -87514,7 +111935,7 @@ SQLITE_API int sqlite3_config(int op, ...){
     /* Mutex configuration options are only available in a threadsafe
     ** compile. 
     */
-#if SQLITE_THREADSAFE
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0
     case SQLITE_CONFIG_SINGLETHREAD: {
       /* Disable all mutexing */
       sqlite3GlobalConfig.bCoreMutex = 0;
@@ -87571,7 +111992,7 @@ SQLITE_API int sqlite3_config(int op, ...){
       break;
     }
     case SQLITE_CONFIG_PAGECACHE: {
-      /* Designate a buffer for scratch memory space */
+      /* Designate a buffer for page cache memory space */
       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
       sqlite3GlobalConfig.szPage = va_arg(ap, int);
       sqlite3GlobalConfig.nPage = va_arg(ap, int);
@@ -87579,16 +112000,25 @@ SQLITE_API int sqlite3_config(int op, ...){
     }
 
     case SQLITE_CONFIG_PCACHE: {
-      /* Specify an alternative malloc implementation */
-      sqlite3GlobalConfig.pcache = *va_arg(ap, sqlite3_pcache_methods*);
+      /* no-op */
+      break;
+    }
+    case SQLITE_CONFIG_GETPCACHE: {
+      /* now an error */
+      rc = SQLITE_ERROR;
       break;
     }
 
-    case SQLITE_CONFIG_GETPCACHE: {
-      if( sqlite3GlobalConfig.pcache.xInit==0 ){
+    case SQLITE_CONFIG_PCACHE2: {
+      /* Specify an alternative page cache implementation */
+      sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
+      break;
+    }
+    case SQLITE_CONFIG_GETPCACHE2: {
+      if( sqlite3GlobalConfig.pcache2.xInit==0 ){
         sqlite3PCacheSetDefault();
       }
-      *va_arg(ap, sqlite3_pcache_methods*) = sqlite3GlobalConfig.pcache;
+      *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
       break;
     }
 
@@ -87599,6 +112029,13 @@ SQLITE_API int sqlite3_config(int op, ...){
       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
 
+      if( sqlite3GlobalConfig.mnReq<1 ){
+        sqlite3GlobalConfig.mnReq = 1;
+      }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
+        /* cap min request size at 2^12 */
+        sqlite3GlobalConfig.mnReq = (1<<12);
+      }
+
       if( sqlite3GlobalConfig.pHeap==0 ){
         /* If the heap pointer is NULL, then restore the malloc implementation
         ** back to NULL pointers too.  This will cause the malloc to go
@@ -87610,7 +112047,6 @@ SQLITE_API int sqlite3_config(int op, ...){
         /* The heap pointer is not NULL, then install one of the
         ** mem5.c/mem3.c methods. If neither ENABLE_MEMSYS3 nor
         ** ENABLE_MEMSYS5 is defined, return an error.
-        ** the default case and return an error.
         */
 #ifdef SQLITE_ENABLE_MEMSYS3
         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
@@ -87628,6 +112064,26 @@ SQLITE_API int sqlite3_config(int op, ...){
       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
       break;
     }
+    
+    /* Record a pointer to the logger funcction and its first argument.
+    ** The default is NULL.  Logging is disabled if the function pointer is
+    ** NULL.
+    */
+    case SQLITE_CONFIG_LOG: {
+      /* MSVC is picky about pulling func ptrs from va lists.
+      ** http://support.microsoft.com/kb/47961
+      ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
+      */
+      typedef void(*LOGFUNC_t)(void*,int,const char*);
+      sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
+      sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
+      break;
+    }
+
+    case SQLITE_CONFIG_URI: {
+      sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
+      break;
+    }
 
     default: {
       rc = SQLITE_ERROR;
@@ -87654,27 +112110,37 @@ static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
   if( db->lookaside.nOut ){
     return SQLITE_BUSY;
   }
-  if( sz<0 ) sz = 0;
-  if( cnt<0 ) cnt = 0;
-  if( pBuf==0 ){
-    sz = (sz + 7)&~7;
-    sqlite3BeginBenignMalloc();
-    pStart = sqlite3Malloc( sz*cnt );
-    sqlite3EndBenignMalloc();
-  }else{
-    sz = sz&~7;
-    pStart = pBuf;
-  }
+  /* Free any existing lookaside buffer for this handle before
+  ** allocating a new one so we don't have to have space for 
+  ** both at the same time.
+  */
   if( db->lookaside.bMalloced ){
     sqlite3_free(db->lookaside.pStart);
   }
+  /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
+  ** than a pointer to be useful.
+  */
+  sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
+  if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
+  if( cnt<0 ) cnt = 0;
+  if( sz==0 || cnt==0 ){
+    sz = 0;
+    pStart = 0;
+  }else if( pBuf==0 ){
+    sqlite3BeginBenignMalloc();
+    pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
+    sqlite3EndBenignMalloc();
+    if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
+  }else{
+    pStart = pBuf;
+  }
   db->lookaside.pStart = pStart;
   db->lookaside.pFree = 0;
   db->lookaside.sz = (u16)sz;
-  db->lookaside.bMalloced = pBuf==0 ?1:0;
   if( pStart ){
     int i;
     LookasideSlot *p;
+    assert( sz > (int)sizeof(LookasideSlot*) );
     p = (LookasideSlot*)pStart;
     for(i=cnt-1; i>=0; i--){
       p->pNext = db->lookaside.pFree;
@@ -87683,9 +112149,11 @@ static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
     }
     db->lookaside.pEnd = p;
     db->lookaside.bEnabled = 1;
+    db->lookaside.bMalloced = pBuf==0 ?1:0;
   }else{
     db->lookaside.pEnd = 0;
     db->lookaside.bEnabled = 0;
+    db->lookaside.bMalloced = 0;
   }
   return SQLITE_OK;
 }
@@ -87697,6 +112165,26 @@ SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
   return db->mutex;
 }
 
+/*
+** Free up as much memory as we can from the given database
+** connection.
+*/
+SQLITE_API int sqlite3_db_release_memory(sqlite3 *db){
+  int i;
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      Pager *pPager = sqlite3BtreePager(pBt);
+      sqlite3PagerShrink(pPager);
+    }
+  }
+  sqlite3BtreeLeaveAll(db);
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
 /*
 ** Configuration settings for an individual database connection
 */
@@ -87706,14 +112194,42 @@ SQLITE_API int sqlite3_db_config(sqlite3 *db, int op, ...){
   va_start(ap, op);
   switch( op ){
     case SQLITE_DBCONFIG_LOOKASIDE: {
-      void *pBuf = va_arg(ap, void*);
-      int sz = va_arg(ap, int);
-      int cnt = va_arg(ap, int);
+      void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
+      int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
+      int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
       rc = setupLookaside(db, pBuf, sz, cnt);
       break;
     }
     default: {
-      rc = SQLITE_ERROR;
+      static const struct {
+        int op;      /* The opcode */
+        u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
+      } aFlagOp[] = {
+        { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
+        { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
+      };
+      unsigned int i;
+      rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
+      for(i=0; i<ArraySize(aFlagOp); i++){
+        if( aFlagOp[i].op==op ){
+          int onoff = va_arg(ap, int);
+          int *pRes = va_arg(ap, int*);
+          int oldFlags = db->flags;
+          if( onoff>0 ){
+            db->flags |= aFlagOp[i].mask;
+          }else if( onoff==0 ){
+            db->flags &= ~aFlagOp[i].mask;
+          }
+          if( oldFlags!=db->flags ){
+            sqlite3ExpirePreparedStatements(db);
+          }
+          if( pRes ){
+            *pRes = (db->flags & aFlagOp[i].mask)!=0;
+          }
+          rc = SQLITE_OK;
+          break;
+        }
+      }
       break;
     }
   }
@@ -87814,34 +112330,82 @@ SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *db){
     sqlite3DbFree(db, pTmp);
   }
   db->nSavepoint = 0;
+  db->nStatement = 0;
   db->isTransactionSavepoint = 0;
 }
 
+/*
+** Invoke the destructor function associated with FuncDef p, if any. Except,
+** if this is not the last copy of the function, do not invoke it. Multiple
+** copies of a single function are created when create_function() is called
+** with SQLITE_ANY as the encoding.
+*/
+static void functionDestroy(sqlite3 *db, FuncDef *p){
+  FuncDestructor *pDestructor = p->pDestructor;
+  if( pDestructor ){
+    pDestructor->nRef--;
+    if( pDestructor->nRef==0 ){
+      pDestructor->xDestroy(pDestructor->pUserData);
+      sqlite3DbFree(db, pDestructor);
+    }
+  }
+}
+
+/*
+** Disconnect all sqlite3_vtab objects that belong to database connection
+** db. This is called when db is being closed.
+*/
+static void disconnectAllVtab(sqlite3 *db){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int i;
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Schema *pSchema = db->aDb[i].pSchema;
+    if( db->aDb[i].pSchema ){
+      HashElem *p;
+      for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
+        Table *pTab = (Table *)sqliteHashData(p);
+        if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
+      }
+    }
+  }
+  sqlite3BtreeLeaveAll(db);
+#else
+  UNUSED_PARAMETER(db);
+#endif
+}
+
+/*
+** Return TRUE if database connection db has unfinalized prepared
+** statements or unfinished sqlite3_backup objects.  
+*/
+static int connectionIsBusy(sqlite3 *db){
+  int j;
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( db->pVdbe ) return 1;
+  for(j=0; j<db->nDb; j++){
+    Btree *pBt = db->aDb[j].pBt;
+    if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
+  }
+  return 0;
+}
+
 /*
 ** Close an existing SQLite database
 */
-SQLITE_API int sqlite3_close(sqlite3 *db){
-  HashElem *i;
-  int j;
-
+static int sqlite3Close(sqlite3 *db, int forceZombie){
   if( !db ){
     return SQLITE_OK;
   }
   if( !sqlite3SafetyCheckSickOrOk(db) ){
-    return SQLITE_MISUSE;
+    return SQLITE_MISUSE_BKPT;
   }
   sqlite3_mutex_enter(db->mutex);
 
-#ifdef SQLITE_SSE
-  {
-    extern void sqlite3SseCleanup(sqlite3*);
-    sqlite3SseCleanup(db);
-  }
-#endif 
+  /* Force xDisconnect calls on all virtual tables */
+  disconnectAllVtab(db);
 
-  sqlite3ResetInternalSchema(db, 0);
-
-  /* If a transaction is open, the ResetInternalSchema() call above
+  /* If a transaction is open, the disconnectAllVtab() call above
   ** will not have called the xDisconnect() method on any virtual
   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
   ** call will do so. We need to do this before the check for active
@@ -87850,18 +112414,67 @@ SQLITE_API int sqlite3_close(sqlite3 *db){
   */
   sqlite3VtabRollback(db);
 
-  /* If there are any outstanding VMs, return SQLITE_BUSY. */
-  if( db->pVdbe ){
-    sqlite3Error(db, SQLITE_BUSY, 
-        "Unable to close due to unfinalised statements");
+  /* Legacy behavior (sqlite3_close() behavior) is to return
+  ** SQLITE_BUSY if the connection can not be closed immediately.
+  */
+  if( !forceZombie && connectionIsBusy(db) ){
+    sqlite3Error(db, SQLITE_BUSY, "unable to close due to unfinalized "
+       "statements or unfinished backups");
     sqlite3_mutex_leave(db->mutex);
     return SQLITE_BUSY;
   }
-  assert( sqlite3SafetyCheckSickOrOk(db) );
+
+  /* Convert the connection into a zombie and then close it.
+  */
+  db->magic = SQLITE_MAGIC_ZOMBIE;
+  sqlite3LeaveMutexAndCloseZombie(db);
+  return SQLITE_OK;
+}
+
+/*
+** Two variations on the public interface for closing a database
+** connection. The sqlite3_close() version returns SQLITE_BUSY and
+** leaves the connection option if there are unfinalized prepared
+** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
+** version forces the connection to become a zombie if there are
+** unclosed resources, and arranges for deallocation when the last
+** prepare statement or sqlite3_backup closes.
+*/
+SQLITE_API int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
+SQLITE_API int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
+
+
+/*
+** Close the mutex on database connection db.
+**
+** Furthermore, if database connection db is a zombie (meaning that there
+** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
+** every sqlite3_stmt has now been finalized and every sqlite3_backup has
+** finished, then free all resources.
+*/
+SQLITE_PRIVATE void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
+  HashElem *i;                    /* Hash table iterator */
+  int j;
+
+  /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
+  ** or if the connection has not yet been closed by sqlite3_close_v2(),
+  ** then just leave the mutex and return.
+  */
+  if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
+    sqlite3_mutex_leave(db->mutex);
+    return;
+  }
+
+  /* If we reach this point, it means that the database connection has
+  ** closed all sqlite3_stmt and sqlite3_backup objects and has been
+  ** pased to sqlite3_close (meaning that it is a zombie).  Therefore,
+  ** go ahead and free all resources.
+  */
 
   /* Free any outstanding Savepoint structures. */
   sqlite3CloseSavepoints(db);
 
+  /* Close all database connections */
   for(j=0; j<db->nDb; j++){
     struct Db *pDb = &db->aDb[j];
     if( pDb->pBt ){
@@ -87872,14 +112485,28 @@ SQLITE_API int sqlite3_close(sqlite3 *db){
       }
     }
   }
-  sqlite3ResetInternalSchema(db, 0);
+  /* Clear the TEMP schema separately and last */
+  if( db->aDb[1].pSchema ){
+    sqlite3SchemaClear(db->aDb[1].pSchema);
+  }
+  sqlite3VtabUnlockList(db);
+
+  /* Free up the array of auxiliary databases */
+  sqlite3CollapseDatabaseArray(db);
   assert( db->nDb<=2 );
   assert( db->aDb==db->aDbStatic );
+
+  /* Tell the code in notify.c that the connection no longer holds any
+  ** locks and does not require any further unlock-notify callbacks.
+  */
+  sqlite3ConnectionClosed(db);
+
   for(j=0; j<ArraySize(db->aFunc.a); j++){
     FuncDef *pNext, *pHash, *p;
     for(p=db->aFunc.a[j]; p; p=pHash){
       pHash = p->pHash;
       while( p ){
+        functionDestroy(db, p);
         pNext = p->pNext;
         sqlite3DbFree(db, p);
         p = pNext;
@@ -87931,23 +112558,26 @@ SQLITE_API int sqlite3_close(sqlite3 *db){
     sqlite3_free(db->lookaside.pStart);
   }
   sqlite3_free(db);
-  return SQLITE_OK;
 }
 
 /*
-** Rollback all database files.
+** Rollback all database files.  If tripCode is not SQLITE_OK, then
+** any open cursors are invalidated ("tripped" - as in "tripping a circuit
+** breaker") and made to return tripCode if there are any further
+** attempts to use that cursor.
 */
-SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db){
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db, int tripCode){
   int i;
   int inTrans = 0;
   assert( sqlite3_mutex_held(db->mutex) );
   sqlite3BeginBenignMalloc();
   for(i=0; i<db->nDb; i++){
-    if( db->aDb[i].pBt ){
-      if( sqlite3BtreeIsInTrans(db->aDb[i].pBt) ){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      if( sqlite3BtreeIsInTrans(p) ){
         inTrans = 1;
       }
-      sqlite3BtreeRollback(db->aDb[i].pBt);
+      sqlite3BtreeRollback(p, tripCode);
       db->aDb[i].inTrans = 0;
     }
   }
@@ -87956,9 +112586,12 @@ SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db){
 
   if( db->flags&SQLITE_InternChanges ){
     sqlite3ExpirePreparedStatements(db);
-    sqlite3ResetInternalSchema(db, 0);
+    sqlite3ResetAllSchemasOfConnection(db);
   }
 
+  /* Any deferred constraint violations have now been resolved. */
+  db->nDeferredCons = 0;
+
   /* If one has been configured, invoke the rollback-hook callback */
   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
     db->xRollbackCallback(db->pRollbackArg);
@@ -87970,37 +112603,50 @@ SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db){
 ** argument.
 */
 SQLITE_PRIVATE const char *sqlite3ErrStr(int rc){
-  const char *z;
-  switch( rc & 0xff ){
-    case SQLITE_ROW:
-    case SQLITE_DONE:
-    case SQLITE_OK:         z = "not an error";                          break;
-    case SQLITE_ERROR:      z = "SQL logic error or missing database";   break;
-    case SQLITE_PERM:       z = "access permission denied";              break;
-    case SQLITE_ABORT:      z = "callback requested query abort";        break;
-    case SQLITE_BUSY:       z = "database is locked";                    break;
-    case SQLITE_LOCKED:     z = "database table is locked";              break;
-    case SQLITE_NOMEM:      z = "out of memory";                         break;
-    case SQLITE_READONLY:   z = "attempt to write a readonly database";  break;
-    case SQLITE_INTERRUPT:  z = "interrupted";                           break;
-    case SQLITE_IOERR:      z = "disk I/O error";                        break;
-    case SQLITE_CORRUPT:    z = "database disk image is malformed";      break;
-    case SQLITE_FULL:       z = "database or disk is full";              break;
-    case SQLITE_CANTOPEN:   z = "unable to open database file";          break;
-    case SQLITE_EMPTY:      z = "table contains no data";                break;
-    case SQLITE_SCHEMA:     z = "database schema has changed";           break;
-    case SQLITE_TOOBIG:     z = "String or BLOB exceeded size limit";    break;
-    case SQLITE_CONSTRAINT: z = "constraint failed";                     break;
-    case SQLITE_MISMATCH:   z = "datatype mismatch";                     break;
-    case SQLITE_MISUSE:     z = "library routine called out of sequence";break;
-    case SQLITE_NOLFS:      z = "large file support is disabled";        break;
-    case SQLITE_AUTH:       z = "authorization denied";                  break;
-    case SQLITE_FORMAT:     z = "auxiliary database format error";       break;
-    case SQLITE_RANGE:      z = "bind or column index out of range";     break;
-    case SQLITE_NOTADB:     z = "file is encrypted or is not a database";break;
-    default:                z = "unknown error";                         break;
+  static const char* const aMsg[] = {
+    /* SQLITE_OK          */ "not an error",
+    /* SQLITE_ERROR       */ "SQL logic error or missing database",
+    /* SQLITE_INTERNAL    */ 0,
+    /* SQLITE_PERM        */ "access permission denied",
+    /* SQLITE_ABORT       */ "callback requested query abort",
+    /* SQLITE_BUSY        */ "database is locked",
+    /* SQLITE_LOCKED      */ "database table is locked",
+    /* SQLITE_NOMEM       */ "out of memory",
+    /* SQLITE_READONLY    */ "attempt to write a readonly database",
+    /* SQLITE_INTERRUPT   */ "interrupted",
+    /* SQLITE_IOERR       */ "disk I/O error",
+    /* SQLITE_CORRUPT     */ "database disk image is malformed",
+    /* SQLITE_NOTFOUND    */ "unknown operation",
+    /* SQLITE_FULL        */ "database or disk is full",
+    /* SQLITE_CANTOPEN    */ "unable to open database file",
+    /* SQLITE_PROTOCOL    */ "locking protocol",
+    /* SQLITE_EMPTY       */ "table contains no data",
+    /* SQLITE_SCHEMA      */ "database schema has changed",
+    /* SQLITE_TOOBIG      */ "string or blob too big",
+    /* SQLITE_CONSTRAINT  */ "constraint failed",
+    /* SQLITE_MISMATCH    */ "datatype mismatch",
+    /* SQLITE_MISUSE      */ "library routine called out of sequence",
+    /* SQLITE_NOLFS       */ "large file support is disabled",
+    /* SQLITE_AUTH        */ "authorization denied",
+    /* SQLITE_FORMAT      */ "auxiliary database format error",
+    /* SQLITE_RANGE       */ "bind or column index out of range",
+    /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
+  };
+  const char *zErr = "unknown error";
+  switch( rc ){
+    case SQLITE_ABORT_ROLLBACK: {
+      zErr = "abort due to ROLLBACK";
+      break;
+    }
+    default: {
+      rc &= 0xff;
+      if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
+        zErr = aMsg[rc];
+      }
+      break;
+    }
   }
-  return z;
+  return zErr;
 }
 
 /*
@@ -88018,7 +112664,7 @@ static int sqliteDefaultBusyCallback(
      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
   static const u8 totals[] =
      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
-# define NDELAY (sizeof(delays)/sizeof(delays[0]))
+# define NDELAY ArraySize(delays)
   sqlite3 *db = (sqlite3 *)ptr;
   int timeout = db->busyTimeout;
   int delay, prior;
@@ -88147,7 +112793,8 @@ SQLITE_PRIVATE int sqlite3CreateFunc(
   void *pUserData,
   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
-  void (*xFinal)(sqlite3_context*)
+  void (*xFinal)(sqlite3_context*),
+  FuncDestructor *pDestructor
 ){
   FuncDef *p;
   int nName;
@@ -88158,9 +112805,8 @@ SQLITE_PRIVATE int sqlite3CreateFunc(
       (!xFunc && (xFinal && !xStep)) ||
       (!xFunc && (!xFinal && xStep)) ||
       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
-      (255<(nName = sqlite3Strlen(db, zFunctionName))) ){
-    sqlite3Error(db, SQLITE_ERROR, "bad parameters");
-    return SQLITE_ERROR;
+      (255<(nName = sqlite3Strlen30( zFunctionName))) ){
+    return SQLITE_MISUSE_BKPT;
   }
   
 #ifndef SQLITE_OMIT_UTF16
@@ -88176,10 +112822,10 @@ SQLITE_PRIVATE int sqlite3CreateFunc(
   }else if( enc==SQLITE_ANY ){
     int rc;
     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8,
-         pUserData, xFunc, xStep, xFinal);
+         pUserData, xFunc, xStep, xFinal, pDestructor);
     if( rc==SQLITE_OK ){
       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE,
-          pUserData, xFunc, xStep, xFinal);
+          pUserData, xFunc, xStep, xFinal, pDestructor);
     }
     if( rc!=SQLITE_OK ){
       return rc;
@@ -88199,7 +112845,7 @@ SQLITE_PRIVATE int sqlite3CreateFunc(
   if( p && p->iPrefEnc==enc && p->nArg==nArg ){
     if( db->activeVdbeCnt ){
       sqlite3Error(db, SQLITE_BUSY, 
-        "Unable to delete/modify user-function due to active statements");
+        "unable to delete/modify user-function due to active statements");
       assert( !db->mallocFailed );
       return SQLITE_BUSY;
     }else{
@@ -88212,6 +112858,15 @@ SQLITE_PRIVATE int sqlite3CreateFunc(
   if( !p ){
     return SQLITE_NOMEM;
   }
+
+  /* If an older version of the function with a configured destructor is
+  ** being replaced invoke the destructor function here. */
+  functionDestroy(db, p);
+
+  if( pDestructor ){
+    pDestructor->nRef++;
+  }
+  p->pDestructor = pDestructor;
   p->flags = 0;
   p->xFunc = xFunc;
   p->xStep = xStep;
@@ -88226,7 +112881,7 @@ SQLITE_PRIVATE int sqlite3CreateFunc(
 */
 SQLITE_API int sqlite3_create_function(
   sqlite3 *db,
-  const char *zFunctionName,
+  const char *zFunc,
   int nArg,
   int enc,
   void *p,
@@ -88234,9 +112889,41 @@ SQLITE_API int sqlite3_create_function(
   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
   void (*xFinal)(sqlite3_context*)
 ){
-  int rc;
+  return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xFunc, xStep,
+                                    xFinal, 0);
+}
+
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*),
+  void (*xDestroy)(void *)
+){
+  int rc = SQLITE_ERROR;
+  FuncDestructor *pArg = 0;
   sqlite3_mutex_enter(db->mutex);
-  rc = sqlite3CreateFunc(db, zFunctionName, nArg, enc, p, xFunc, xStep, xFinal);
+  if( xDestroy ){
+    pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
+    if( !pArg ){
+      xDestroy(p);
+      goto out;
+    }
+    pArg->xDestroy = xDestroy;
+    pArg->pUserData = p;
+  }
+  rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, pArg);
+  if( pArg && pArg->nRef==0 ){
+    assert( rc!=SQLITE_OK );
+    xDestroy(p);
+    sqlite3DbFree(db, pArg);
+  }
+
+ out:
   rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
@@ -88257,8 +112944,8 @@ SQLITE_API int sqlite3_create_function16(
   char *zFunc8;
   sqlite3_mutex_enter(db->mutex);
   assert( !db->mallocFailed );
-  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1);
-  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal);
+  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
+  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
   sqlite3DbFree(db, zFunc8);
   rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
@@ -88284,14 +112971,14 @@ SQLITE_API int sqlite3_overload_function(
   const char *zName,
   int nArg
 ){
-  int nName = sqlite3Strlen(db, zName);
-  int rc;
+  int nName = sqlite3Strlen30(zName);
+  int rc = SQLITE_OK;
   sqlite3_mutex_enter(db->mutex);
   if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
-    sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
-                      0, sqlite3InvalidFunction, 0, 0);
+    rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
+                           0, sqlite3InvalidFunction, 0, 0, 0);
   }
-  rc = sqlite3ApiExit(db, SQLITE_OK);
+  rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
 }
@@ -88337,9 +113024,8 @@ SQLITE_API void *sqlite3_profile(
 }
 #endif /* SQLITE_OMIT_TRACE */
 
-/*** EXPERIMENTAL ***
-**
-** Register a function to be invoked when a transaction comments.
+/*
+** Register a function to be invoked when a transaction commits.
 ** If the invoked function returns non-zero, then the commit becomes a
 ** rollback.
 */
@@ -88393,81 +113079,206 @@ SQLITE_API void *sqlite3_rollback_hook(
   return pRet;
 }
 
+#ifndef SQLITE_OMIT_WAL
 /*
-** This routine is called to create a connection to a database BTree
-** driver.  If zFilename is the name of a file, then that file is
-** opened and used.  If zFilename is the magic name ":memory:" then
-** the database is stored in memory (and is thus forgotten as soon as
-** the connection is closed.)  If zFilename is NULL then the database
-** is a "virtual" database for transient use only and is deleted as
-** soon as the connection is closed.
+** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
+** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
+** is greater than sqlite3.pWalArg cast to an integer (the value configured by
+** wal_autocheckpoint()).
+*/ 
+SQLITE_PRIVATE int sqlite3WalDefaultHook(
+  void *pClientData,     /* Argument */
+  sqlite3 *db,           /* Connection */
+  const char *zDb,       /* Database */
+  int nFrame             /* Size of WAL */
+){
+  if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
+    sqlite3BeginBenignMalloc();
+    sqlite3_wal_checkpoint(db, zDb);
+    sqlite3EndBenignMalloc();
+  }
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_WAL */
+
+/*
+** Configure an sqlite3_wal_hook() callback to automatically checkpoint
+** a database after committing a transaction if there are nFrame or
+** more frames in the log file. Passing zero or a negative value as the
+** nFrame parameter disables automatic checkpoints entirely.
 **
-** A virtual database can be either a disk file (that is automatically
-** deleted when the file is closed) or it an be held entirely in memory,
-** depending on the values of the SQLITE_TEMP_STORE compile-time macro and the
-** db->temp_store variable, according to the following chart:
+** The callback registered by this function replaces any existing callback
+** registered using sqlite3_wal_hook(). Likewise, registering a callback
+** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
+** configured by this function.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
+#ifdef SQLITE_OMIT_WAL
+  UNUSED_PARAMETER(db);
+  UNUSED_PARAMETER(nFrame);
+#else
+  if( nFrame>0 ){
+    sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
+  }else{
+    sqlite3_wal_hook(db, 0, 0);
+  }
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Register a callback to be invoked each time a transaction is written
+** into the write-ahead-log by this database connection.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3 *db,                    /* Attach the hook to this db handle */
+  int(*xCallback)(void *, sqlite3*, const char*, int),
+  void *pArg                      /* First argument passed to xCallback() */
+){
+#ifndef SQLITE_OMIT_WAL
+  void *pRet;
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pWalArg;
+  db->xWalCallback = xCallback;
+  db->pWalArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+#else
+  return 0;
+#endif
+}
+
+/*
+** Checkpoint database zDb.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+){
+#ifdef SQLITE_OMIT_WAL
+  return SQLITE_OK;
+#else
+  int rc;                         /* Return code */
+  int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
+
+  /* Initialize the output variables to -1 in case an error occurs. */
+  if( pnLog ) *pnLog = -1;
+  if( pnCkpt ) *pnCkpt = -1;
+
+  assert( SQLITE_CHECKPOINT_FULL>SQLITE_CHECKPOINT_PASSIVE );
+  assert( SQLITE_CHECKPOINT_FULL<SQLITE_CHECKPOINT_RESTART );
+  assert( SQLITE_CHECKPOINT_PASSIVE+2==SQLITE_CHECKPOINT_RESTART );
+  if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_RESTART ){
+    return SQLITE_MISUSE;
+  }
+
+  sqlite3_mutex_enter(db->mutex);
+  if( zDb && zDb[0] ){
+    iDb = sqlite3FindDbName(db, zDb);
+  }
+  if( iDb<0 ){
+    rc = SQLITE_ERROR;
+    sqlite3Error(db, SQLITE_ERROR, "unknown database: %s", zDb);
+  }else{
+    rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
+    sqlite3Error(db, rc, 0);
+  }
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+#endif
+}
+
+
+/*
+** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
+** to contains a zero-length string, all attached databases are 
+** checkpointed.
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
+  return sqlite3_wal_checkpoint_v2(db, zDb, SQLITE_CHECKPOINT_PASSIVE, 0, 0);
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Run a checkpoint on database iDb. This is a no-op if database iDb is
+** not currently open in WAL mode.
+**
+** If a transaction is open on the database being checkpointed, this 
+** function returns SQLITE_LOCKED and a checkpoint is not attempted. If 
+** an error occurs while running the checkpoint, an SQLite error code is 
+** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
+**
+** The mutex on database handle db should be held by the caller. The mutex
+** associated with the specific b-tree being checkpointed is taken by
+** this function while the checkpoint is running.
+**
+** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
+** checkpointed. If an error is encountered it is returned immediately -
+** no attempt is made to checkpoint any remaining databases.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
+*/
+SQLITE_PRIVATE int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Used to iterate through attached dbs */
+  int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( !pnLog || *pnLog==-1 );
+  assert( !pnCkpt || *pnCkpt==-1 );
+
+  for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
+    if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
+      rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
+      pnLog = 0;
+      pnCkpt = 0;
+      if( rc==SQLITE_BUSY ){
+        bBusy = 1;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
+}
+#endif /* SQLITE_OMIT_WAL */
+
+/*
+** This function returns true if main-memory should be used instead of
+** a temporary file for transient pager files and statement journals.
+** The value returned depends on the value of db->temp_store (runtime
+** parameter) and the compile time value of SQLITE_TEMP_STORE. The
+** following table describes the relationship between these two values
+** and this functions return value.
 **
 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
 **   -----------------     --------------     ------------------------------
-**   0                     any                file
-**   1                     1                  file
-**   1                     2                  memory
-**   1                     0                  file
-**   2                     1                  file
-**   2                     2                  memory
-**   2                     0                  memory
-**   3                     any                memory
+**   0                     any                file      (return 0)
+**   1                     1                  file      (return 0)
+**   1                     2                  memory    (return 1)
+**   1                     0                  file      (return 0)
+**   2                     1                  file      (return 0)
+**   2                     2                  memory    (return 1)
+**   2                     0                  memory    (return 1)
+**   3                     any                memory    (return 1)
 */
-SQLITE_PRIVATE int sqlite3BtreeFactory(
-  const sqlite3 *db,        /* Main database when opening aux otherwise 0 */
-  const char *zFilename,    /* Name of the file containing the BTree database */
-  int omitJournal,          /* if TRUE then do not journal this file */
-  int nCache,               /* How many pages in the page cache */
-  int vfsFlags,             /* Flags passed through to vfsOpen */
-  Btree **ppBtree           /* Pointer to new Btree object written here */
-){
-  int btFlags = 0;
-  int rc;
-  
-  assert( sqlite3_mutex_held(db->mutex) );
-  assert( ppBtree != 0);
-  if( omitJournal ){
-    btFlags |= BTREE_OMIT_JOURNAL;
-  }
-  if( db->flags & SQLITE_NoReadlock ){
-    btFlags |= BTREE_NO_READLOCK;
-  }
-  if( zFilename==0 ){
-#if SQLITE_TEMP_STORE==0
-    /* Do nothing */
-#endif
-#ifndef SQLITE_OMIT_MEMORYDB
+SQLITE_PRIVATE int sqlite3TempInMemory(const sqlite3 *db){
 #if SQLITE_TEMP_STORE==1
-    if( db->temp_store==2 ) zFilename = ":memory:";
+  return ( db->temp_store==2 );
 #endif
 #if SQLITE_TEMP_STORE==2
-    if( db->temp_store!=1 ) zFilename = ":memory:";
+  return ( db->temp_store!=1 );
 #endif
 #if SQLITE_TEMP_STORE==3
-    zFilename = ":memory:";
+  return 1;
+#endif
+#if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
+  return 0;
 #endif
-#endif /* SQLITE_OMIT_MEMORYDB */
-  }
-
-  if( (vfsFlags & SQLITE_OPEN_MAIN_DB)!=0 && (zFilename==0 || *zFilename==0) ){
-    vfsFlags = (vfsFlags & ~SQLITE_OPEN_MAIN_DB) | SQLITE_OPEN_TEMP_DB;
-  }
-  rc = sqlite3BtreeOpen(zFilename, (sqlite3 *)db, ppBtree, btFlags, vfsFlags);
-
-  /* If the B-Tree was successfully opened, set the pager-cache size to the
-  ** default value. Except, if the call to BtreeOpen() returned a handle
-  ** open on an existing shared pager-cache, do not change the pager-cache 
-  ** size.
-  */
-  if( rc==SQLITE_OK && 0==sqlite3BtreeSchema(*ppBtree, 0, 0) ){
-    sqlite3BtreeSetCacheSize(*ppBtree, nCache);
-  }
-  return rc;
 }
 
 /*
@@ -88480,17 +113291,17 @@ SQLITE_API const char *sqlite3_errmsg(sqlite3 *db){
     return sqlite3ErrStr(SQLITE_NOMEM);
   }
   if( !sqlite3SafetyCheckSickOrOk(db) ){
-    return sqlite3ErrStr(SQLITE_MISUSE);
-  }
-  if( db->mallocFailed ){
-    return sqlite3ErrStr(SQLITE_NOMEM);
+    return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
   }
   sqlite3_mutex_enter(db->mutex);
-  assert( !db->mallocFailed );
-  z = (char*)sqlite3_value_text(db->pErr);
-  assert( !db->mallocFailed );
-  if( z==0 ){
-    z = sqlite3ErrStr(db->errCode);
+  if( db->mallocFailed ){
+    z = sqlite3ErrStr(SQLITE_NOMEM);
+  }else{
+    z = (char*)sqlite3_value_text(db->pErr);
+    assert( !db->mallocFailed );
+    if( z==0 ){
+      z = sqlite3ErrStr(db->errCode);
+    }
   }
   sqlite3_mutex_leave(db->mutex);
   return z;
@@ -88502,46 +113313,42 @@ SQLITE_API const char *sqlite3_errmsg(sqlite3 *db){
 ** error.
 */
 SQLITE_API const void *sqlite3_errmsg16(sqlite3 *db){
-  /* Because all the characters in the string are in the unicode
-  ** range 0x00-0xFF, if we pad the big-endian string with a 
-  ** zero byte, we can obtain the little-endian string with
-  ** &big_endian[1].
-  */
-  static const char outOfMemBe[] = {
-    0, 'o', 0, 'u', 0, 't', 0, ' ', 
-    0, 'o', 0, 'f', 0, ' ', 
-    0, 'm', 0, 'e', 0, 'm', 0, 'o', 0, 'r', 0, 'y', 0, 0, 0
+  static const u16 outOfMem[] = {
+    'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
   };
-  static const char misuseBe [] = {
-    0, 'l', 0, 'i', 0, 'b', 0, 'r', 0, 'a', 0, 'r', 0, 'y', 0, ' ', 
-    0, 'r', 0, 'o', 0, 'u', 0, 't', 0, 'i', 0, 'n', 0, 'e', 0, ' ', 
-    0, 'c', 0, 'a', 0, 'l', 0, 'l', 0, 'e', 0, 'd', 0, ' ', 
-    0, 'o', 0, 'u', 0, 't', 0, ' ', 
-    0, 'o', 0, 'f', 0, ' ', 
-    0, 's', 0, 'e', 0, 'q', 0, 'u', 0, 'e', 0, 'n', 0, 'c', 0, 'e', 0, 0, 0
+  static const u16 misuse[] = {
+    'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ', 
+    'r', 'o', 'u', 't', 'i', 'n', 'e', ' ', 
+    'c', 'a', 'l', 'l', 'e', 'd', ' ', 
+    'o', 'u', 't', ' ', 
+    'o', 'f', ' ', 
+    's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
   };
 
   const void *z;
   if( !db ){
-    return (void *)(&outOfMemBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
+    return (void *)outOfMem;
   }
   if( !sqlite3SafetyCheckSickOrOk(db) ){
-    return (void *)(&misuseBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
+    return (void *)misuse;
   }
   sqlite3_mutex_enter(db->mutex);
-  assert( !db->mallocFailed );
-  z = sqlite3_value_text16(db->pErr);
-  if( z==0 ){
-    sqlite3ValueSetStr(db->pErr, -1, sqlite3ErrStr(db->errCode),
-         SQLITE_UTF8, SQLITE_STATIC);
+  if( db->mallocFailed ){
+    z = (void *)outOfMem;
+  }else{
     z = sqlite3_value_text16(db->pErr);
+    if( z==0 ){
+      sqlite3ValueSetStr(db->pErr, -1, sqlite3ErrStr(db->errCode),
+           SQLITE_UTF8, SQLITE_STATIC);
+      z = sqlite3_value_text16(db->pErr);
+    }
+    /* A malloc() may have failed within the call to sqlite3_value_text16()
+    ** above. If this is the case, then the db->mallocFailed flag needs to
+    ** be cleared before returning. Do this directly, instead of via
+    ** sqlite3ApiExit(), to avoid setting the database handle error message.
+    */
+    db->mallocFailed = 0;
   }
-  /* A malloc() may have failed within the call to sqlite3_value_text16()
-  ** above. If this is the case, then the db->mallocFailed flag needs to
-  ** be cleared before returning. Do this directly, instead of via
-  ** sqlite3ApiExit(), to avoid setting the database handle error message.
-  */
-  db->mallocFailed = 0;
   sqlite3_mutex_leave(db->mutex);
   return z;
 }
@@ -88553,7 +113360,7 @@ SQLITE_API const void *sqlite3_errmsg16(sqlite3 *db){
 */
 SQLITE_API int sqlite3_errcode(sqlite3 *db){
   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
-    return SQLITE_MISUSE;
+    return SQLITE_MISUSE_BKPT;
   }
   if( !db || db->mallocFailed ){
     return SQLITE_NOMEM;
@@ -88562,7 +113369,7 @@ SQLITE_API int sqlite3_errcode(sqlite3 *db){
 }
 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db){
   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
-    return SQLITE_MISUSE;
+    return SQLITE_MISUSE_BKPT;
   }
   if( !db || db->mallocFailed ){
     return SQLITE_NOMEM;
@@ -88575,16 +113382,16 @@ SQLITE_API int sqlite3_extended_errcode(sqlite3 *db){
 ** and the encoding is enc.
 */
 static int createCollation(
-  sqlite3* db, 
+  sqlite3* db,
   const char *zName, 
-  int enc, 
+  u8 enc,
   void* pCtx,
   int(*xCompare)(void*,int,const void*,int,const void*),
   void(*xDel)(void*)
 ){
   CollSeq *pColl;
   int enc2;
-  int nName;
+  int nName = sqlite3Strlen30(zName);
   
   assert( sqlite3_mutex_held(db->mutex) );
 
@@ -88592,24 +113399,25 @@ static int createCollation(
   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
   */
-  enc2 = enc & ~SQLITE_UTF16_ALIGNED;
-  if( enc2==SQLITE_UTF16 ){
+  enc2 = enc;
+  testcase( enc2==SQLITE_UTF16 );
+  testcase( enc2==SQLITE_UTF16_ALIGNED );
+  if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
     enc2 = SQLITE_UTF16NATIVE;
   }
-  if( (enc2&~3)!=0 ){
-    return SQLITE_MISUSE;
+  if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
+    return SQLITE_MISUSE_BKPT;
   }
 
   /* Check if this call is removing or replacing an existing collation 
   ** sequence. If so, and there are active VMs, return busy. If there
   ** are no active VMs, invalidate any pre-compiled statements.
   */
-  nName = sqlite3Strlen(db, zName);
-  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, nName, 0);
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
   if( pColl && pColl->xCmp ){
     if( db->activeVdbeCnt ){
       sqlite3Error(db, SQLITE_BUSY, 
-        "Unable to delete/modify collation sequence due to active statements");
+        "unable to delete/modify collation sequence due to active statements");
       return SQLITE_BUSY;
     }
     sqlite3ExpirePreparedStatements(db);
@@ -88635,13 +113443,12 @@ static int createCollation(
     }
   }
 
-  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, nName, 1);
-  if( pColl ){
-    pColl->xCmp = xCompare;
-    pColl->pUser = pCtx;
-    pColl->xDel = xDel;
-    pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
-  }
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
+  if( pColl==0 ) return SQLITE_NOMEM;
+  pColl->xCmp = xCompare;
+  pColl->pUser = pCtx;
+  pColl->xDel = xDel;
+  pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
   sqlite3Error(db, SQLITE_OK, 0);
   return SQLITE_OK;
 }
@@ -88663,6 +113470,7 @@ static const int aHardLimit[] = {
   SQLITE_MAX_ATTACHED,
   SQLITE_MAX_LIKE_PATTERN_LENGTH,
   SQLITE_MAX_VARIABLE_NUMBER,
+  SQLITE_MAX_TRIGGER_DEPTH,
 };
 
 /*
@@ -88686,18 +113494,18 @@ static const int aHardLimit[] = {
 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
 #endif
-#if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>30
-# error SQLITE_MAX_ATTACHED must be between 0 and 30
+#if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>62
+# error SQLITE_MAX_ATTACHED must be between 0 and 62
 #endif
 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
 #endif
-#if SQLITE_MAX_VARIABLE_NUMBER<1
-# error SQLITE_MAX_VARIABLE_NUMBER must be at least 1
-#endif
 #if SQLITE_MAX_COLUMN>32767
 # error SQLITE_MAX_COLUMN must not exceed 32767
 #endif
+#if SQLITE_MAX_TRIGGER_DEPTH<1
+# error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
+#endif
 
 
 /*
@@ -88712,19 +113520,274 @@ static const int aHardLimit[] = {
 */
 SQLITE_API int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
   int oldLimit;
+
+
+  /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
+  ** there is a hard upper bound set at compile-time by a C preprocessor
+  ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
+  ** "_MAX_".)
+  */
+  assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
+  assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
+  assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
+  assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
+  assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
+  assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
+  assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
+                                               SQLITE_MAX_LIKE_PATTERN_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
+  assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
+  assert( SQLITE_LIMIT_TRIGGER_DEPTH==(SQLITE_N_LIMIT-1) );
+
+
   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
     return -1;
   }
   oldLimit = db->aLimit[limitId];
-  if( newLimit>=0 ){
+  if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
     if( newLimit>aHardLimit[limitId] ){
-      newLimit = aHardLimit[limitId];
+      newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
     }
     db->aLimit[limitId] = newLimit;
   }
-  return oldLimit;
+  return oldLimit;                     /* IMP: R-53341-35419 */
 }
 
+/*
+** This function is used to parse both URIs and non-URI filenames passed by the
+** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
+** URIs specified as part of ATTACH statements.
+**
+** The first argument to this function is the name of the VFS to use (or
+** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
+** query parameter. The second argument contains the URI (or non-URI filename)
+** itself. When this function is called the *pFlags variable should contain
+** the default flags to open the database handle with. The value stored in
+** *pFlags may be updated before returning if the URI filename contains 
+** "cache=xxx" or "mode=xxx" query parameters.
+**
+** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
+** the VFS that should be used to open the database file. *pzFile is set to
+** point to a buffer containing the name of the file to open. It is the 
+** responsibility of the caller to eventually call sqlite3_free() to release
+** this buffer.
+**
+** If an error occurs, then an SQLite error code is returned and *pzErrMsg
+** may be set to point to a buffer containing an English language error 
+** message. It is the responsibility of the caller to eventually release
+** this buffer by calling sqlite3_free().
+*/
+SQLITE_PRIVATE int sqlite3ParseUri(
+  const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
+  const char *zUri,               /* Nul-terminated URI to parse */
+  unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
+  sqlite3_vfs **ppVfs,            /* OUT: VFS to use */ 
+  char **pzFile,                  /* OUT: Filename component of URI */
+  char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
+){
+  int rc = SQLITE_OK;
+  unsigned int flags = *pFlags;
+  const char *zVfs = zDefaultVfs;
+  char *zFile;
+  char c;
+  int nUri = sqlite3Strlen30(zUri);
+
+  assert( *pzErrMsg==0 );
+
+  if( ((flags & SQLITE_OPEN_URI) || sqlite3GlobalConfig.bOpenUri) 
+   && nUri>=5 && memcmp(zUri, "file:", 5)==0 
+  ){
+    char *zOpt;
+    int eState;                   /* Parser state when parsing URI */
+    int iIn;                      /* Input character index */
+    int iOut = 0;                 /* Output character index */
+    int nByte = nUri+2;           /* Bytes of space to allocate */
+
+    /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen 
+    ** method that there may be extra parameters following the file-name.  */
+    flags |= SQLITE_OPEN_URI;
+
+    for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
+    zFile = sqlite3_malloc(nByte);
+    if( !zFile ) return SQLITE_NOMEM;
+
+    /* Discard the scheme and authority segments of the URI. */
+    if( zUri[5]=='/' && zUri[6]=='/' ){
+      iIn = 7;
+      while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
+
+      if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
+        *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s", 
+            iIn-7, &zUri[7]);
+        rc = SQLITE_ERROR;
+        goto parse_uri_out;
+      }
+    }else{
+      iIn = 5;
+    }
+
+    /* Copy the filename and any query parameters into the zFile buffer. 
+    ** Decode %HH escape codes along the way. 
+    **
+    ** Within this loop, variable eState may be set to 0, 1 or 2, depending
+    ** on the parsing context. As follows:
+    **
+    **   0: Parsing file-name.
+    **   1: Parsing name section of a name=value query parameter.
+    **   2: Parsing value section of a name=value query parameter.
+    */
+    eState = 0;
+    while( (c = zUri[iIn])!=0 && c!='#' ){
+      iIn++;
+      if( c=='%' 
+       && sqlite3Isxdigit(zUri[iIn]) 
+       && sqlite3Isxdigit(zUri[iIn+1]) 
+      ){
+        int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
+        octet += sqlite3HexToInt(zUri[iIn++]);
+
+        assert( octet>=0 && octet<256 );
+        if( octet==0 ){
+          /* This branch is taken when "%00" appears within the URI. In this
+          ** case we ignore all text in the remainder of the path, name or
+          ** value currently being parsed. So ignore the current character
+          ** and skip to the next "?", "=" or "&", as appropriate. */
+          while( (c = zUri[iIn])!=0 && c!='#' 
+              && (eState!=0 || c!='?')
+              && (eState!=1 || (c!='=' && c!='&'))
+              && (eState!=2 || c!='&')
+          ){
+            iIn++;
+          }
+          continue;
+        }
+        c = octet;
+      }else if( eState==1 && (c=='&' || c=='=') ){
+        if( zFile[iOut-1]==0 ){
+          /* An empty option name. Ignore this option altogether. */
+          while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
+          continue;
+        }
+        if( c=='&' ){
+          zFile[iOut++] = '\0';
+        }else{
+          eState = 2;
+        }
+        c = 0;
+      }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
+        c = 0;
+        eState = 1;
+      }
+      zFile[iOut++] = c;
+    }
+    if( eState==1 ) zFile[iOut++] = '\0';
+    zFile[iOut++] = '\0';
+    zFile[iOut++] = '\0';
+
+    /* Check if there were any options specified that should be interpreted 
+    ** here. Options that are interpreted here include "vfs" and those that
+    ** correspond to flags that may be passed to the sqlite3_open_v2()
+    ** method. */
+    zOpt = &zFile[sqlite3Strlen30(zFile)+1];
+    while( zOpt[0] ){
+      int nOpt = sqlite3Strlen30(zOpt);
+      char *zVal = &zOpt[nOpt+1];
+      int nVal = sqlite3Strlen30(zVal);
+
+      if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
+        zVfs = zVal;
+      }else{
+        struct OpenMode {
+          const char *z;
+          int mode;
+        } *aMode = 0;
+        char *zModeType = 0;
+        int mask = 0;
+        int limit = 0;
+
+        if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
+          static struct OpenMode aCacheMode[] = {
+            { "shared",  SQLITE_OPEN_SHAREDCACHE },
+            { "private", SQLITE_OPEN_PRIVATECACHE },
+            { 0, 0 }
+          };
+
+          mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
+          aMode = aCacheMode;
+          limit = mask;
+          zModeType = "cache";
+        }
+        if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
+          static struct OpenMode aOpenMode[] = {
+            { "ro",  SQLITE_OPEN_READONLY },
+            { "rw",  SQLITE_OPEN_READWRITE }, 
+            { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
+            { "memory", SQLITE_OPEN_MEMORY },
+            { 0, 0 }
+          };
+
+          mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
+                   | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
+          aMode = aOpenMode;
+          limit = mask & flags;
+          zModeType = "access";
+        }
+
+        if( aMode ){
+          int i;
+          int mode = 0;
+          for(i=0; aMode[i].z; i++){
+            const char *z = aMode[i].z;
+            if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
+              mode = aMode[i].mode;
+              break;
+            }
+          }
+          if( mode==0 ){
+            *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
+            rc = SQLITE_ERROR;
+            goto parse_uri_out;
+          }
+          if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
+            *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
+                                        zModeType, zVal);
+            rc = SQLITE_PERM;
+            goto parse_uri_out;
+          }
+          flags = (flags & ~mask) | mode;
+        }
+      }
+
+      zOpt = &zVal[nVal+1];
+    }
+
+  }else{
+    zFile = sqlite3_malloc(nUri+2);
+    if( !zFile ) return SQLITE_NOMEM;
+    memcpy(zFile, zUri, nUri);
+    zFile[nUri] = '\0';
+    zFile[nUri+1] = '\0';
+    flags &= ~SQLITE_OPEN_URI;
+  }
+
+  *ppVfs = sqlite3_vfs_find(zVfs);
+  if( *ppVfs==0 ){
+    *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
+    rc = SQLITE_ERROR;
+  }
+ parse_uri_out:
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(zFile);
+    zFile = 0;
+  }
+  *pFlags = flags;
+  *pzFile = zFile;
+  return rc;
+}
+
+
 /*
 ** This routine does the work of opening a database on behalf of
 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"  
@@ -88733,19 +113796,39 @@ SQLITE_API int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
 static int openDatabase(
   const char *zFilename, /* Database filename UTF-8 encoded */
   sqlite3 **ppDb,        /* OUT: Returned database handle */
-  unsigned flags,        /* Operational flags */
+  unsigned int flags,    /* Operational flags */
   const char *zVfs       /* Name of the VFS to use */
 ){
-  sqlite3 *db;
-  int rc;
-  CollSeq *pColl;
-  int isThreadsafe;
+  sqlite3 *db;                    /* Store allocated handle here */
+  int rc;                         /* Return code */
+  int isThreadsafe;               /* True for threadsafe connections */
+  char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
+  char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
 
+  *ppDb = 0;
 #ifndef SQLITE_OMIT_AUTOINIT
   rc = sqlite3_initialize();
   if( rc ) return rc;
 #endif
 
+  /* Only allow sensible combinations of bits in the flags argument.  
+  ** Throw an error if any non-sense combination is used.  If we
+  ** do not block illegal combinations here, it could trigger
+  ** assert() statements in deeper layers.  Sensible combinations
+  ** are:
+  **
+  **  1:  SQLITE_OPEN_READONLY
+  **  2:  SQLITE_OPEN_READWRITE
+  **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
+  */
+  assert( SQLITE_OPEN_READONLY  == 0x01 );
+  assert( SQLITE_OPEN_READWRITE == 0x02 );
+  assert( SQLITE_OPEN_CREATE    == 0x04 );
+  testcase( (1<<(flags&7))==0x02 ); /* READONLY */
+  testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
+  testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
+  if( ((1<<(flags&7)) & 0x46)==0 ) return SQLITE_MISUSE_BKPT;
+
   if( sqlite3GlobalConfig.bCoreMutex==0 ){
     isThreadsafe = 0;
   }else if( flags & SQLITE_OPEN_NOMUTEX ){
@@ -88755,9 +113838,23 @@ static int openDatabase(
   }else{
     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
   }
+  if( flags & SQLITE_OPEN_PRIVATECACHE ){
+    flags &= ~SQLITE_OPEN_SHAREDCACHE;
+  }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
+    flags |= SQLITE_OPEN_SHAREDCACHE;
+  }
 
-  /* Remove harmful bits from the flags parameter */
+  /* Remove harmful bits from the flags parameter
+  **
+  ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
+  ** dealt with in the previous code block.  Besides these, the only
+  ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
+  ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
+  ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
+  ** off all other flags.
+  */
   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
+               SQLITE_OPEN_EXCLUSIVE |
                SQLITE_OPEN_MAIN_DB |
                SQLITE_OPEN_TEMP_DB | 
                SQLITE_OPEN_TRANSIENT_DB | 
@@ -88766,7 +113863,8 @@ static int openDatabase(
                SQLITE_OPEN_SUBJOURNAL | 
                SQLITE_OPEN_MASTER_JOURNAL |
                SQLITE_OPEN_NOMUTEX |
-               SQLITE_OPEN_FULLMUTEX
+               SQLITE_OPEN_FULLMUTEX |
+               SQLITE_OPEN_WAL
              );
 
   /* Allocate the sqlite data structure */
@@ -88782,7 +113880,6 @@ static int openDatabase(
   }
   sqlite3_mutex_enter(db->mutex);
   db->errMask = 0xff;
-  db->priorNewRowid = 0;
   db->nDb = 2;
   db->magic = SQLITE_MAGIC_BUSY;
   db->aDb = db->aDbStatic;
@@ -88792,25 +113889,24 @@ static int openDatabase(
   db->autoCommit = 1;
   db->nextAutovac = -1;
   db->nextPagesize = 0;
-  db->flags |= SQLITE_ShortColNames
+  db->flags |= SQLITE_ShortColNames | SQLITE_AutoIndex | SQLITE_EnableTrigger
 #if SQLITE_DEFAULT_FILE_FORMAT<4
                  | SQLITE_LegacyFileFmt
 #endif
 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
                  | SQLITE_LoadExtension
 #endif
-      ;
-  sqlite3HashInit(&db->aCollSeq, 0);
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-  sqlite3HashInit(&db->aModule, 0);
+#if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+                 | SQLITE_RecTriggers
+#endif
+#if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
+                 | SQLITE_ForeignKeys
+#endif
+      ;
+  sqlite3HashInit(&db->aCollSeq);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3HashInit(&db->aModule);
 #endif
-
-  db->pVfs = sqlite3_vfs_find(zVfs);
-  if( !db->pVfs ){
-    rc = SQLITE_ERROR;
-    sqlite3Error(db, rc, "no such vfs: %s", zVfs);
-    goto opendb_out;
-  }
 
   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
   ** and UTF-16, so add a version for each to avoid any unnecessary
@@ -88823,24 +113919,25 @@ static int openDatabase(
   if( db->mallocFailed ){
     goto opendb_out;
   }
-  db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
+  db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
   assert( db->pDfltColl!=0 );
 
   /* Also add a UTF-8 case-insensitive collation sequence. */
   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
 
-  /* Set flags on the built-in collating sequences */
-  db->pDfltColl->type = SQLITE_COLL_BINARY;
-  pColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "NOCASE", 6, 0);
-  if( pColl ){
-    pColl->type = SQLITE_COLL_NOCASE;
+  /* Parse the filename/URI argument. */
+  db->openFlags = flags;
+  rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
+    sqlite3Error(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
+    sqlite3_free(zErrMsg);
+    goto opendb_out;
   }
 
   /* Open the backend database driver */
-  db->openFlags = flags;
-  rc = sqlite3BtreeFactory(db, zFilename, 0, SQLITE_DEFAULT_CACHE_SIZE, 
-                           flags | SQLITE_OPEN_MAIN_DB,
-                           &db->aDb[0].pBt);
+  rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
+                        flags | SQLITE_OPEN_MAIN_DB);
   if( rc!=SQLITE_OK ){
     if( rc==SQLITE_IOERR_NOMEM ){
       rc = SQLITE_NOMEM;
@@ -88857,10 +113954,8 @@ static int openDatabase(
   */
   db->aDb[0].zName = "main";
   db->aDb[0].safety_level = 3;
-#ifndef SQLITE_OMIT_TEMPDB
   db->aDb[1].zName = "temp";
   db->aDb[1].safety_level = 1;
-#endif
 
   db->magic = SQLITE_MAGIC_OPEN;
   if( db->mallocFailed ){
@@ -88877,9 +113972,13 @@ static int openDatabase(
   /* Load automatic extensions - extensions that have been registered
   ** using the sqlite3_automatic_extension() API.
   */
-  (void)sqlite3AutoLoadExtensions(db);
-  if( sqlite3_errcode(db)!=SQLITE_OK ){
-    goto opendb_out;
+  rc = sqlite3_errcode(db);
+  if( rc==SQLITE_OK ){
+    sqlite3AutoLoadExtensions(db);
+    rc = sqlite3_errcode(db);
+    if( rc!=SQLITE_OK ){
+      goto opendb_out;
+    }
   }
 
 #ifdef SQLITE_ENABLE_FTS1
@@ -88930,12 +114029,16 @@ static int openDatabase(
   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
                         sqlite3GlobalConfig.nLookaside);
 
+  sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
+
 opendb_out:
+  sqlite3_free(zOpen);
   if( db ){
     assert( db->mutex!=0 || isThreadsafe==0 || sqlite3GlobalConfig.bFullMutex==0 );
     sqlite3_mutex_leave(db->mutex);
   }
   rc = sqlite3_errcode(db);
+  assert( db!=0 || rc==SQLITE_NOMEM );
   if( rc==SQLITE_NOMEM ){
     sqlite3_close(db);
     db = 0;
@@ -88962,7 +114065,7 @@ SQLITE_API int sqlite3_open_v2(
   int flags,              /* Flags */
   const char *zVfs        /* Name of VFS module to use */
 ){
-  return openDatabase(filename, ppDb, flags, zVfs);
+  return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
 }
 
 #ifndef SQLITE_OMIT_UTF16
@@ -89016,7 +114119,7 @@ SQLITE_API int sqlite3_create_collation(
   int rc;
   sqlite3_mutex_enter(db->mutex);
   assert( !db->mallocFailed );
-  rc = createCollation(db, zName, enc, pCtx, xCompare, 0);
+  rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, 0);
   rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
@@ -89036,7 +114139,7 @@ SQLITE_API int sqlite3_create_collation_v2(
   int rc;
   sqlite3_mutex_enter(db->mutex);
   assert( !db->mallocFailed );
-  rc = createCollation(db, zName, enc, pCtx, xCompare, xDel);
+  rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
   rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
@@ -89057,9 +114160,9 @@ SQLITE_API int sqlite3_create_collation16(
   char *zName8;
   sqlite3_mutex_enter(db->mutex);
   assert( !db->mallocFailed );
-  zName8 = sqlite3Utf16to8(db, zName, -1);
+  zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
   if( zName8 ){
-    rc = createCollation(db, zName8, enc, pCtx, xCompare, 0);
+    rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
     sqlite3DbFree(db, zName8);
   }
   rc = sqlite3ApiExit(db, rc);
@@ -89104,7 +114207,6 @@ SQLITE_API int sqlite3_collation_needed16(
 }
 #endif /* SQLITE_OMIT_UTF16 */
 
-#ifndef SQLITE_OMIT_GLOBALRECOVER
 #ifndef SQLITE_OMIT_DEPRECATED
 /*
 ** This function is now an anachronism. It used to be used to recover from a
@@ -89114,7 +114216,6 @@ SQLITE_API int sqlite3_global_recover(void){
   return SQLITE_OK;
 }
 #endif
-#endif
 
 /*
 ** Test to see whether or not the database connection is in autocommit
@@ -89128,16 +114229,39 @@ SQLITE_API int sqlite3_get_autocommit(sqlite3 *db){
   return db->autoCommit;
 }
 
-#ifdef SQLITE_DEBUG
 /*
-** The following routine is subtituted for constant SQLITE_CORRUPT in
-** debugging builds.  This provides a way to set a breakpoint for when
-** corruption is first detected.
+** The following routines are subtitutes for constants SQLITE_CORRUPT,
+** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
+** constants.  They server two purposes:
+**
+**   1.  Serve as a convenient place to set a breakpoint in a debugger
+**       to detect when version error conditions occurs.
+**
+**   2.  Invoke sqlite3_log() to provide the source code location where
+**       a low-level error is first detected.
 */
-SQLITE_PRIVATE int sqlite3Corrupt(void){
+SQLITE_PRIVATE int sqlite3CorruptError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  sqlite3_log(SQLITE_CORRUPT,
+              "database corruption at line %d of [%.10s]",
+              lineno, 20+sqlite3_sourceid());
   return SQLITE_CORRUPT;
 }
-#endif
+SQLITE_PRIVATE int sqlite3MisuseError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  sqlite3_log(SQLITE_MISUSE, 
+              "misuse at line %d of [%.10s]",
+              lineno, 20+sqlite3_sourceid());
+  return SQLITE_MISUSE;
+}
+SQLITE_PRIVATE int sqlite3CantopenError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  sqlite3_log(SQLITE_CANTOPEN, 
+              "cannot open file at line %d of [%.10s]",
+              lineno, 20+sqlite3_sourceid());
+  return SQLITE_CANTOPEN;
+}
+
 
 #ifndef SQLITE_OMIT_DEPRECATED
 /*
@@ -89181,10 +114305,8 @@ SQLITE_API int sqlite3_table_column_metadata(
 
   /* Ensure the database schema has been loaded */
   sqlite3_mutex_enter(db->mutex);
-  (void)sqlite3SafetyOn(db);
   sqlite3BtreeEnterAll(db);
   rc = sqlite3Init(db, &zErrMsg);
-  sqlite3BtreeLeaveAll(db);
   if( SQLITE_OK!=rc ){
     goto error_out;
   }
@@ -89240,7 +114362,7 @@ SQLITE_API int sqlite3_table_column_metadata(
   }
 
 error_out:
-  (void)sqlite3SafetyOff(db);
+  sqlite3BtreeLeaveAll(db);
 
   /* Whether the function call succeeded or failed, set the output parameters
   ** to whatever their local counterparts contain. If an error did occur,
@@ -89297,30 +114419,27 @@ SQLITE_API int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
 */
 SQLITE_API int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
   int rc = SQLITE_ERROR;
-  int iDb;
+  Btree *pBtree;
+
   sqlite3_mutex_enter(db->mutex);
-  if( zDbName==0 ){
-    iDb = 0;
-  }else{
-    for(iDb=0; iDb<db->nDb; iDb++){
-      if( strcmp(db->aDb[iDb].zName, zDbName)==0 ) break;
-    }
-  }
-  if( iDb<db->nDb ){
-    Btree *pBtree = db->aDb[iDb].pBt;
-    if( pBtree ){
-      Pager *pPager;
-      sqlite3_file *fd;
-      sqlite3BtreeEnter(pBtree);
-      pPager = sqlite3BtreePager(pBtree);
-      assert( pPager!=0 );
-      fd = sqlite3PagerFile(pPager);
-      assert( fd!=0 );
-      if( fd->pMethods ){
-        rc = sqlite3OsFileControl(fd, op, pArg);
-      }
-      sqlite3BtreeLeave(pBtree);
+  pBtree = sqlite3DbNameToBtree(db, zDbName);
+  if( pBtree ){
+    Pager *pPager;
+    sqlite3_file *fd;
+    sqlite3BtreeEnter(pBtree);
+    pPager = sqlite3BtreePager(pBtree);
+    assert( pPager!=0 );
+    fd = sqlite3PagerFile(pPager);
+    assert( fd!=0 );
+    if( op==SQLITE_FCNTL_FILE_POINTER ){
+      *(sqlite3_file**)pArg = fd;
+      rc = SQLITE_OK;
+    }else if( fd->pMethods ){
+      rc = sqlite3OsFileControl(fd, op, pArg);
+    }else{
+      rc = SQLITE_NOTFOUND;
     }
+    sqlite3BtreeLeave(pBtree);
   }
   sqlite3_mutex_leave(db->mutex);
   return rc;   
@@ -89394,13 +114513,594 @@ SQLITE_API int sqlite3_test_control(int op, ...){
       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
       break;
     }
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
+    **
+    ** Set the PENDING byte to the value in the argument, if X>0.
+    ** Make no changes if X==0.  Return the value of the pending byte
+    ** as it existing before this routine was called.
+    **
+    ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
+    ** an incompatible database file format.  Changing the PENDING byte
+    ** while any database connection is open results in undefined and
+    ** dileterious behavior.
+    */
+    case SQLITE_TESTCTRL_PENDING_BYTE: {
+      rc = PENDING_BYTE;
+#ifndef SQLITE_OMIT_WSD
+      {
+        unsigned int newVal = va_arg(ap, unsigned int);
+        if( newVal ) sqlite3PendingByte = newVal;
+      }
+#endif
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
+    **
+    ** This action provides a run-time test to see whether or not
+    ** assert() was enabled at compile-time.  If X is true and assert()
+    ** is enabled, then the return value is true.  If X is true and
+    ** assert() is disabled, then the return value is zero.  If X is
+    ** false and assert() is enabled, then the assertion fires and the
+    ** process aborts.  If X is false and assert() is disabled, then the
+    ** return value is zero.
+    */
+    case SQLITE_TESTCTRL_ASSERT: {
+      volatile int x = 0;
+      assert( (x = va_arg(ap,int))!=0 );
+      rc = x;
+      break;
+    }
+
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
+    **
+    ** This action provides a run-time test to see how the ALWAYS and
+    ** NEVER macros were defined at compile-time.
+    **
+    ** The return value is ALWAYS(X).  
+    **
+    ** The recommended test is X==2.  If the return value is 2, that means
+    ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
+    ** default setting.  If the return value is 1, then ALWAYS() is either
+    ** hard-coded to true or else it asserts if its argument is false.
+    ** The first behavior (hard-coded to true) is the case if
+    ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
+    ** behavior (assert if the argument to ALWAYS() is false) is the case if
+    ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
+    **
+    ** The run-time test procedure might look something like this:
+    **
+    **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
+    **      // ALWAYS() and NEVER() are no-op pass-through macros
+    **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
+    **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
+    **    }else{
+    **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
+    **    }
+    */
+    case SQLITE_TESTCTRL_ALWAYS: {
+      int x = va_arg(ap,int);
+      rc = ALWAYS(x);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
+    **
+    ** Set the nReserve size to N for the main database on the database
+    ** connection db.
+    */
+    case SQLITE_TESTCTRL_RESERVE: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int x = va_arg(ap,int);
+      sqlite3_mutex_enter(db->mutex);
+      sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
+      sqlite3_mutex_leave(db->mutex);
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
+    **
+    ** Enable or disable various optimizations for testing purposes.  The 
+    ** argument N is a bitmask of optimizations to be disabled.  For normal
+    ** operation N should be 0.  The idea is that a test program (like the
+    ** SQL Logic Test or SLT test module) can run the same SQL multiple times
+    ** with various optimizations disabled to verify that the same answer
+    ** is obtained in every case.
+    */
+    case SQLITE_TESTCTRL_OPTIMIZATIONS: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int x = va_arg(ap,int);
+      db->flags = (x & SQLITE_OptMask) | (db->flags & ~SQLITE_OptMask);
+      break;
+    }
+
+#ifdef SQLITE_N_KEYWORD
+    /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
+    **
+    ** If zWord is a keyword recognized by the parser, then return the
+    ** number of keywords.  Or if zWord is not a keyword, return 0.
+    ** 
+    ** This test feature is only available in the amalgamation since
+    ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
+    ** is built using separate source files.
+    */
+    case SQLITE_TESTCTRL_ISKEYWORD: {
+      const char *zWord = va_arg(ap, const char*);
+      int n = sqlite3Strlen30(zWord);
+      rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
+      break;
+    }
+#endif 
+
+    /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
+    **
+    ** Pass pFree into sqlite3ScratchFree(). 
+    ** If sz>0 then allocate a scratch buffer into pNew.  
+    */
+    case SQLITE_TESTCTRL_SCRATCHMALLOC: {
+      void *pFree, **ppNew;
+      int sz;
+      sz = va_arg(ap, int);
+      ppNew = va_arg(ap, void**);
+      pFree = va_arg(ap, void*);
+      if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
+      sqlite3ScratchFree(pFree);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
+    **
+    ** If parameter onoff is non-zero, configure the wrappers so that all
+    ** subsequent calls to localtime() and variants fail. If onoff is zero,
+    ** undo this setting.
+    */
+    case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
+      sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
+      break;
+    }
+
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_EXPLAIN_STMT,
+    **                        sqlite3_stmt*,const char**);
+    **
+    ** If compiled with SQLITE_ENABLE_TREE_EXPLAIN, each sqlite3_stmt holds
+    ** a string that describes the optimized parse tree.  This test-control
+    ** returns a pointer to that string.
+    */
+    case SQLITE_TESTCTRL_EXPLAIN_STMT: {
+      sqlite3_stmt *pStmt = va_arg(ap, sqlite3_stmt*);
+      const char **pzRet = va_arg(ap, const char**);
+      *pzRet = sqlite3VdbeExplanation((Vdbe*)pStmt);
+      break;
+    }
+#endif
+
   }
   va_end(ap);
 #endif /* SQLITE_OMIT_BUILTIN_TEST */
   return rc;
 }
 
+/*
+** This is a utility routine, useful to VFS implementations, that checks
+** to see if a database file was a URI that contained a specific query 
+** parameter, and if so obtains the value of the query parameter.
+**
+** The zFilename argument is the filename pointer passed into the xOpen()
+** method of a VFS implementation.  The zParam argument is the name of the
+** query parameter we seek.  This routine returns the value of the zParam
+** parameter if it exists.  If the parameter does not exist, this routine
+** returns a NULL pointer.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
+  if( zFilename==0 ) return 0;
+  zFilename += sqlite3Strlen30(zFilename) + 1;
+  while( zFilename[0] ){
+    int x = strcmp(zFilename, zParam);
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+    if( x==0 ) return zFilename;
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+  }
+  return 0;
+}
+
+/*
+** Return a boolean value for a query parameter.
+*/
+SQLITE_API int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
+  const char *z = sqlite3_uri_parameter(zFilename, zParam);
+  bDflt = bDflt!=0;
+  return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
+}
+
+/*
+** Return a 64-bit integer value for a query parameter.
+*/
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(
+  const char *zFilename,    /* Filename as passed to xOpen */
+  const char *zParam,       /* URI parameter sought */
+  sqlite3_int64 bDflt       /* return if parameter is missing */
+){
+  const char *z = sqlite3_uri_parameter(zFilename, zParam);
+  sqlite3_int64 v;
+  if( z && sqlite3Atoi64(z, &v, sqlite3Strlen30(z), SQLITE_UTF8)==SQLITE_OK ){
+    bDflt = v;
+  }
+  return bDflt;
+}
+
+/*
+** Return the Btree pointer identified by zDbName.  Return NULL if not found.
+*/
+SQLITE_PRIVATE Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
+  int i;
+  for(i=0; i<db->nDb; i++){
+    if( db->aDb[i].pBt
+     && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
+    ){
+      return db->aDb[i].pBt;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return the filename of the database associated with a database
+** connection.
+*/
+SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
+  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
+  return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
+}
+
+/*
+** Return 1 if database is read-only or 0 if read/write.  Return -1 if
+** no such database exists.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
+  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
+  return pBt ? sqlite3PagerIsreadonly(sqlite3BtreePager(pBt)) : -1;
+}
+
 /************** End of main.c ************************************************/
+/************** Begin file notify.c ******************************************/
+/*
+** 2009 March 3
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the implementation of the sqlite3_unlock_notify()
+** API method and its associated functionality.
+*/
+
+/* Omit this entire file if SQLITE_ENABLE_UNLOCK_NOTIFY is not defined. */
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+
+/*
+** Public interfaces:
+**
+**   sqlite3ConnectionBlocked()
+**   sqlite3ConnectionUnlocked()
+**   sqlite3ConnectionClosed()
+**   sqlite3_unlock_notify()
+*/
+
+#define assertMutexHeld() \
+  assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER)) )
+
+/*
+** Head of a linked list of all sqlite3 objects created by this process
+** for which either sqlite3.pBlockingConnection or sqlite3.pUnlockConnection
+** is not NULL. This variable may only accessed while the STATIC_MASTER
+** mutex is held.
+*/
+static sqlite3 *SQLITE_WSD sqlite3BlockedList = 0;
+
+#ifndef NDEBUG
+/*
+** This function is a complex assert() that verifies the following 
+** properties of the blocked connections list:
+**
+**   1) Each entry in the list has a non-NULL value for either 
+**      pUnlockConnection or pBlockingConnection, or both.
+**
+**   2) All entries in the list that share a common value for 
+**      xUnlockNotify are grouped together.
+**
+**   3) If the argument db is not NULL, then none of the entries in the
+**      blocked connections list have pUnlockConnection or pBlockingConnection
+**      set to db. This is used when closing connection db.
+*/
+static void checkListProperties(sqlite3 *db){
+  sqlite3 *p;
+  for(p=sqlite3BlockedList; p; p=p->pNextBlocked){
+    int seen = 0;
+    sqlite3 *p2;
+
+    /* Verify property (1) */
+    assert( p->pUnlockConnection || p->pBlockingConnection );
+
+    /* Verify property (2) */
+    for(p2=sqlite3BlockedList; p2!=p; p2=p2->pNextBlocked){
+      if( p2->xUnlockNotify==p->xUnlockNotify ) seen = 1;
+      assert( p2->xUnlockNotify==p->xUnlockNotify || !seen );
+      assert( db==0 || p->pUnlockConnection!=db );
+      assert( db==0 || p->pBlockingConnection!=db );
+    }
+  }
+}
+#else
+# define checkListProperties(x)
+#endif
+
+/*
+** Remove connection db from the blocked connections list. If connection
+** db is not currently a part of the list, this function is a no-op.
+*/
+static void removeFromBlockedList(sqlite3 *db){
+  sqlite3 **pp;
+  assertMutexHeld();
+  for(pp=&sqlite3BlockedList; *pp; pp = &(*pp)->pNextBlocked){
+    if( *pp==db ){
+      *pp = (*pp)->pNextBlocked;
+      break;
+    }
+  }
+}
+
+/*
+** Add connection db to the blocked connections list. It is assumed
+** that it is not already a part of the list.
+*/
+static void addToBlockedList(sqlite3 *db){
+  sqlite3 **pp;
+  assertMutexHeld();
+  for(
+    pp=&sqlite3BlockedList; 
+    *pp && (*pp)->xUnlockNotify!=db->xUnlockNotify; 
+    pp=&(*pp)->pNextBlocked
+  );
+  db->pNextBlocked = *pp;
+  *pp = db;
+}
+
+/*
+** Obtain the STATIC_MASTER mutex.
+*/
+static void enterMutex(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+  checkListProperties(0);
+}
+
+/*
+** Release the STATIC_MASTER mutex.
+*/
+static void leaveMutex(void){
+  assertMutexHeld();
+  checkListProperties(0);
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+
+/*
+** Register an unlock-notify callback.
+**
+** This is called after connection "db" has attempted some operation
+** but has received an SQLITE_LOCKED error because another connection
+** (call it pOther) in the same process was busy using the same shared
+** cache.  pOther is found by looking at db->pBlockingConnection.
+**
+** If there is no blocking connection, the callback is invoked immediately,
+** before this routine returns.
+**
+** If pOther is already blocked on db, then report SQLITE_LOCKED, to indicate
+** a deadlock.
+**
+** Otherwise, make arrangements to invoke xNotify when pOther drops
+** its locks.
+**
+** Each call to this routine overrides any prior callbacks registered
+** on the same "db".  If xNotify==0 then any prior callbacks are immediately
+** cancelled.
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *db,
+  void (*xNotify)(void **, int),
+  void *pArg
+){
+  int rc = SQLITE_OK;
+
+  sqlite3_mutex_enter(db->mutex);
+  enterMutex();
+
+  if( xNotify==0 ){
+    removeFromBlockedList(db);
+    db->pBlockingConnection = 0;
+    db->pUnlockConnection = 0;
+    db->xUnlockNotify = 0;
+    db->pUnlockArg = 0;
+  }else if( 0==db->pBlockingConnection ){
+    /* The blocking transaction has been concluded. Or there never was a 
+    ** blocking transaction. In either case, invoke the notify callback
+    ** immediately. 
+    */
+    xNotify(&pArg, 1);
+  }else{
+    sqlite3 *p;
+
+    for(p=db->pBlockingConnection; p && p!=db; p=p->pUnlockConnection){}
+    if( p ){
+      rc = SQLITE_LOCKED;              /* Deadlock detected. */
+    }else{
+      db->pUnlockConnection = db->pBlockingConnection;
+      db->xUnlockNotify = xNotify;
+      db->pUnlockArg = pArg;
+      removeFromBlockedList(db);
+      addToBlockedList(db);
+    }
+  }
+
+  leaveMutex();
+  assert( !db->mallocFailed );
+  sqlite3Error(db, rc, (rc?"database is deadlocked":0));
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This function is called while stepping or preparing a statement 
+** associated with connection db. The operation will return SQLITE_LOCKED
+** to the user because it requires a lock that will not be available
+** until connection pBlocker concludes its current transaction.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionBlocked(sqlite3 *db, sqlite3 *pBlocker){
+  enterMutex();
+  if( db->pBlockingConnection==0 && db->pUnlockConnection==0 ){
+    addToBlockedList(db);
+  }
+  db->pBlockingConnection = pBlocker;
+  leaveMutex();
+}
+
+/*
+** This function is called when
+** the transaction opened by database db has just finished. Locks held 
+** by database connection db have been released.
+**
+** This function loops through each entry in the blocked connections
+** list and does the following:
+**
+**   1) If the sqlite3.pBlockingConnection member of a list entry is
+**      set to db, then set pBlockingConnection=0.
+**
+**   2) If the sqlite3.pUnlockConnection member of a list entry is
+**      set to db, then invoke the configured unlock-notify callback and
+**      set pUnlockConnection=0.
+**
+**   3) If the two steps above mean that pBlockingConnection==0 and
+**      pUnlockConnection==0, remove the entry from the blocked connections
+**      list.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionUnlocked(sqlite3 *db){
+  void (*xUnlockNotify)(void **, int) = 0; /* Unlock-notify cb to invoke */
+  int nArg = 0;                            /* Number of entries in aArg[] */
+  sqlite3 **pp;                            /* Iterator variable */
+  void **aArg;               /* Arguments to the unlock callback */
+  void **aDyn = 0;           /* Dynamically allocated space for aArg[] */
+  void *aStatic[16];         /* Starter space for aArg[].  No malloc required */
+
+  aArg = aStatic;
+  enterMutex();         /* Enter STATIC_MASTER mutex */
+
+  /* This loop runs once for each entry in the blocked-connections list. */
+  for(pp=&sqlite3BlockedList; *pp; /* no-op */ ){
+    sqlite3 *p = *pp;
+
+    /* Step 1. */
+    if( p->pBlockingConnection==db ){
+      p->pBlockingConnection = 0;
+    }
+
+    /* Step 2. */
+    if( p->pUnlockConnection==db ){
+      assert( p->xUnlockNotify );
+      if( p->xUnlockNotify!=xUnlockNotify && nArg!=0 ){
+        xUnlockNotify(aArg, nArg);
+        nArg = 0;
+      }
+
+      sqlite3BeginBenignMalloc();
+      assert( aArg==aDyn || (aDyn==0 && aArg==aStatic) );
+      assert( nArg<=(int)ArraySize(aStatic) || aArg==aDyn );
+      if( (!aDyn && nArg==(int)ArraySize(aStatic))
+       || (aDyn && nArg==(int)(sqlite3MallocSize(aDyn)/sizeof(void*)))
+      ){
+        /* The aArg[] array needs to grow. */
+        void **pNew = (void **)sqlite3Malloc(nArg*sizeof(void *)*2);
+        if( pNew ){
+          memcpy(pNew, aArg, nArg*sizeof(void *));
+          sqlite3_free(aDyn);
+          aDyn = aArg = pNew;
+        }else{
+          /* This occurs when the array of context pointers that need to
+          ** be passed to the unlock-notify callback is larger than the
+          ** aStatic[] array allocated on the stack and the attempt to 
+          ** allocate a larger array from the heap has failed.
+          **
+          ** This is a difficult situation to handle. Returning an error
+          ** code to the caller is insufficient, as even if an error code
+          ** is returned the transaction on connection db will still be
+          ** closed and the unlock-notify callbacks on blocked connections
+          ** will go unissued. This might cause the application to wait
+          ** indefinitely for an unlock-notify callback that will never 
+          ** arrive.
+          **
+          ** Instead, invoke the unlock-notify callback with the context
+          ** array already accumulated. We can then clear the array and
+          ** begin accumulating any further context pointers without 
+          ** requiring any dynamic allocation. This is sub-optimal because
+          ** it means that instead of one callback with a large array of
+          ** context pointers the application will receive two or more
+          ** callbacks with smaller arrays of context pointers, which will
+          ** reduce the applications ability to prioritize multiple 
+          ** connections. But it is the best that can be done under the
+          ** circumstances.
+          */
+          xUnlockNotify(aArg, nArg);
+          nArg = 0;
+        }
+      }
+      sqlite3EndBenignMalloc();
+
+      aArg[nArg++] = p->pUnlockArg;
+      xUnlockNotify = p->xUnlockNotify;
+      p->pUnlockConnection = 0;
+      p->xUnlockNotify = 0;
+      p->pUnlockArg = 0;
+    }
+
+    /* Step 3. */
+    if( p->pBlockingConnection==0 && p->pUnlockConnection==0 ){
+      /* Remove connection p from the blocked connections list. */
+      *pp = p->pNextBlocked;
+      p->pNextBlocked = 0;
+    }else{
+      pp = &p->pNextBlocked;
+    }
+  }
+
+  if( nArg!=0 ){
+    xUnlockNotify(aArg, nArg);
+  }
+  sqlite3_free(aDyn);
+  leaveMutex();         /* Leave STATIC_MASTER mutex */
+}
+
+/*
+** This is called when the database connection passed as an argument is 
+** being closed. The connection is removed from the blocked list.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionClosed(sqlite3 *db){
+  sqlite3ConnectionUnlocked(db);
+  enterMutex();
+  removeFromBlockedList(db);
+  checkListProperties(db);
+  leaveMutex();
+}
+#endif
+
+/************** End of notify.c **********************************************/
 /************** Begin file fts3.c ********************************************/
 /*
 ** 2006 Oct 10
@@ -89427,9 +115127,6 @@ SQLITE_API int sqlite3_test_control(int op, ...){
 **       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
 */
 
-/* TODO(shess) Consider exporting this comment to an HTML file or the
-** wiki.
-*/
 /* The full-text index is stored in a series of b+tree (-like)
 ** structures called segments which map terms to doclists.  The
 ** structures are like b+trees in layout, but are constructed from the
@@ -89452,30 +115149,40 @@ SQLITE_API int sqlite3_test_control(int op, ...){
 ** 21 bits - BBA
 ** and so on.
 **
-** This is identical to how sqlite encodes varints (see util.c).
+** This is similar in concept to how sqlite encodes "varints" but
+** the encoding is not the same.  SQLite varints are big-endian
+** are are limited to 9 bytes in length whereas FTS3 varints are
+** little-endian and can be up to 10 bytes in length (in theory).
+**
+** Example encodings:
+**
+**     1:    0x01
+**   127:    0x7f
+**   128:    0x81 0x00
 **
 **
 **** Document lists ****
 ** A doclist (document list) holds a docid-sorted list of hits for a
-** given term.  Doclists hold docids, and can optionally associate
-** token positions and offsets with docids.
+** given term.  Doclists hold docids and associated token positions.
+** A docid is the unique integer identifier for a single document.
+** A position is the index of a word within the document.  The first 
+** word of the document has a position of 0.
 **
-** A DL_POSITIONS_OFFSETS doclist is stored like this:
+** FTS3 used to optionally store character offsets using a compile-time
+** option.  But that functionality is no longer supported.
+**
+** A doclist is stored like this:
 **
 ** array {
-**   varint docid;
+**   varint docid;          (delta from previous doclist)
 **   array {                (position list for column 0)
-**     varint position;     (delta from previous position plus POS_BASE)
-**     varint startOffset;  (delta from previous startOffset)
-**     varint endOffset;    (delta from startOffset)
+**     varint position;     (2 more than the delta from previous position)
 **   }
 **   array {
 **     varint POS_COLUMN;   (marks start of position list for new column)
 **     varint column;       (index of new column)
 **     array {
-**       varint position;   (delta from previous position plus POS_BASE)
-**       varint startOffset;(delta from previous startOffset)
-**       varint endOffset;  (delta from startOffset)
+**       varint position;   (2 more than the delta from previous position)
 **     }
 **   }
 **   varint POS_END;        (marks end of positions for this document.
@@ -89483,19 +115190,32 @@ SQLITE_API int sqlite3_test_control(int op, ...){
 **
 ** Here, array { X } means zero or more occurrences of X, adjacent in
 ** memory.  A "position" is an index of a token in the token stream
-** generated by the tokenizer, while an "offset" is a byte offset,
-** both based at 0.  Note that POS_END and POS_COLUMN occur in the
-** same logical place as the position element, and act as sentinals
-** ending a position list array.
+** generated by the tokenizer. Note that POS_END and POS_COLUMN occur 
+** in the same logical place as the position element, and act as sentinals
+** ending a position list array.  POS_END is 0.  POS_COLUMN is 1.
+** The positions numbers are not stored literally but rather as two more
+** than the difference from the prior position, or the just the position plus
+** 2 for the first position.  Example:
 **
-** A DL_POSITIONS doclist omits the startOffset and endOffset
-** information.  A DL_DOCIDS doclist omits both the position and
-** offset information, becoming an array of varint-encoded docids.
+**   label:       A B C D E  F  G H   I  J K
+**   value:     123 5 9 1 1 14 35 0 234 72 0
 **
-** On-disk data is stored as type DL_DEFAULT, so we don't serialize
-** the type.  Due to how deletion is implemented in the segmentation
-** system, on-disk doclists MUST store at least positions.
+** The 123 value is the first docid.  For column zero in this document
+** there are two matches at positions 3 and 10 (5-2 and 9-2+3).  The 1
+** at D signals the start of a new column; the 1 at E indicates that the
+** new column is column number 1.  There are two positions at 12 and 45
+** (14-2 and 35-2+12).  The 0 at H indicate the end-of-document.  The
+** 234 at I is the delta to next docid (357).  It has one position 70
+** (72-2) and then terminates with the 0 at K.
 **
+** A "position-list" is the list of positions for multiple columns for
+** a single docid.  A "column-list" is the set of positions for a single
+** column.  Hence, a position-list consists of one or more column-lists,
+** a document record consists of a docid followed by a position-list and
+** a doclist consists of one or more document records.
+**
+** A bare doclist omits the position information, becoming an 
+** array of varint-encoded docids.
 **
 **** Segment leaf nodes ****
 ** Segment leaf nodes store terms and doclists, ordered by term.  Leaf
@@ -89670,23 +115390,12 @@ SQLITE_API int sqlite3_test_control(int op, ...){
 ** will eventually overtake the earlier data and knock it out.  The
 ** query logic likewise merges doclists so that newer data knocks out
 ** older data.
-**
-** TODO(shess) Provide a VACUUM type operation to clear out all
-** deletions and duplications.  This would basically be a forced merge
-** into a single segment.
 */
 
-#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
-
-#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
-# define SQLITE_CORE 1
-#endif
-
-
-/************** Include fts3_expr.h in the middle of fts3.c ******************/
-/************** Begin file fts3_expr.h ***************************************/
+/************** Include fts3Int.h in the middle of fts3.c ********************/
+/************** Begin file fts3Int.h *****************************************/
 /*
-** 2008 Nov 28
+** 2009 Nov 12
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
@@ -89698,8 +115407,30 @@ SQLITE_API int sqlite3_test_control(int op, ...){
 ******************************************************************************
 **
 */
+#ifndef _FTSINT_H
+#define _FTSINT_H
 
-/************** Include fts3_tokenizer.h in the middle of fts3_expr.h ********/
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG) 
+# define NDEBUG 1
+#endif
+
+/*
+** FTS4 is really an extension for FTS3.  It is enabled using the
+** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also all
+** the SQLITE_ENABLE_FTS4 macro to serve as an alisse for SQLITE_ENABLE_FTS3.
+*/
+#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
+# define SQLITE_ENABLE_FTS3
+#endif
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* If not building as part of the core, include sqlite3ext.h. */
+#ifndef SQLITE_CORE
+SQLITE_API extern const sqlite3_api_routines *sqlite3_api;
+#endif
+
+/************** Include fts3_tokenizer.h in the middle of fts3Int.h **********/
 /************** Begin file fts3_tokenizer.h **********************************/
 /*
 ** 2006 July 10
@@ -89754,7 +115485,7 @@ typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
 struct sqlite3_tokenizer_module {
 
   /*
-  ** Structure version. Should always be set to 0.
+  ** Structure version. Should always be set to 0 or 1.
   */
   int iVersion;
 
@@ -89815,7 +115546,10 @@ struct sqlite3_tokenizer_module {
   ** stemming has been performed). *pnBytes should be set to the length
   ** of this buffer in bytes. The input text that generated the token is
   ** identified by the byte offsets returned in *piStartOffset and
-  ** *piEndOffset.
+  ** *piEndOffset. *piStartOffset should be set to the index of the first
+  ** byte of the token in the input buffer. *piEndOffset should be set
+  ** to the index of the first byte just past the end of the token in
+  ** the input buffer.
   **
   ** The buffer *ppToken is set to point at is managed by the tokenizer
   ** implementation. It is only required to be valid until the next call
@@ -89832,6 +115566,15 @@ struct sqlite3_tokenizer_module {
     int *piEndOffset,    /* OUT: Byte offset of end of token in input buffer */
     int *piPosition      /* OUT: Number of tokens returned before this one */
   );
+
+  /***********************************************************************
+  ** Methods below this point are only available if iVersion>=1.
+  */
+
+  /* 
+  ** Configure the language id of a tokenizer cursor.
+  */
+  int (*xLanguageid)(sqlite3_tokenizer_cursor *pCsr, int iLangid);
 };
 
 struct sqlite3_tokenizer {
@@ -89844,94 +115587,15 @@ struct sqlite3_tokenizer_cursor {
   /* Tokenizer implementations will typically add additional fields */
 };
 
+int fts3_global_term_cnt(int iTerm, int iCol);
+int fts3_term_cnt(int iTerm, int iCol);
+
+
 #endif /* _FTS3_TOKENIZER_H_ */
 
 /************** End of fts3_tokenizer.h **************************************/
-/************** Continuing where we left off in fts3_expr.h ******************/
-
-/*
-** The following describes the syntax supported by the fts3 MATCH
-** operator in a similar format to that used by the lemon parser
-** generator. This module does not use actually lemon, it uses a
-** custom parser.
-**
-**   query ::= andexpr (OR andexpr)*.
-**
-**   andexpr ::= notexpr (AND? notexpr)*.
-**
-**   notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*.
-**   notexpr ::= LP query RP.
-**
-**   nearexpr ::= phrase (NEAR distance_opt nearexpr)*.
-**
-**   distance_opt ::= .
-**   distance_opt ::= / INTEGER.
-**
-**   phrase ::= TOKEN.
-**   phrase ::= COLUMN:TOKEN.
-**   phrase ::= "TOKEN TOKEN TOKEN...".
-*/
-
-typedef struct Fts3Expr Fts3Expr;
-typedef struct Fts3Phrase Fts3Phrase;
-
-/*
-** A "phrase" is a sequence of one or more tokens that must match in
-** sequence.  A single token is the base case and the most common case.
-** For a sequence of tokens contained in "...", nToken will be the number
-** of tokens in the string.
-*/
-struct Fts3Phrase {
-  int nToken;          /* Number of tokens in the phrase */
-  int iColumn;         /* Index of column this phrase must match */
-  int isNot;           /* Phrase prefixed by unary not (-) operator */
-  struct PhraseToken {
-    char *z;              /* Text of the token */
-    int n;                /* Number of bytes in buffer pointed to by z */
-    int isPrefix;         /* True if token ends in with a "*" character */
-  } aToken[1];         /* One entry for each token in the phrase */
-};
-
-/*
-** A tree of these objects forms the RHS of a MATCH operator.
-*/
-struct Fts3Expr {
-  int eType;                 /* One of the FTSQUERY_XXX values defined below */
-  int nNear;                 /* Valid if eType==FTSQUERY_NEAR */
-  Fts3Expr *pParent;         /* pParent->pLeft==this or pParent->pRight==this */
-  Fts3Expr *pLeft;           /* Left operand */
-  Fts3Expr *pRight;          /* Right operand */
-  Fts3Phrase *pPhrase;       /* Valid if eType==FTSQUERY_PHRASE */
-};
-
-SQLITE_PRIVATE int sqlite3Fts3ExprParse(sqlite3_tokenizer *, char **, int, int, 
-                         const char *, int, Fts3Expr **);
-SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *);
-
-/*
-** Candidate values for Fts3Query.eType. Note that the order of the first
-** four values is in order of precedence when parsing expressions. For 
-** example, the following:
-**
-**   "a OR b AND c NOT d NEAR e"
-**
-** is equivalent to:
-**
-**   "a OR (b AND (c NOT (d NEAR e)))"
-*/
-#define FTSQUERY_NEAR   1
-#define FTSQUERY_NOT    2
-#define FTSQUERY_AND    3
-#define FTSQUERY_OR     4
-#define FTSQUERY_PHRASE 5
-
-#ifdef SQLITE_TEST
-SQLITE_PRIVATE void sqlite3Fts3ExprInitTestInterface(sqlite3 *db);
-#endif
-
-/************** End of fts3_expr.h *******************************************/
-/************** Continuing where we left off in fts3.c ***********************/
-/************** Include fts3_hash.h in the middle of fts3.c ******************/
+/************** Continuing where we left off in fts3Int.h ********************/
+/************** Include fts3_hash.h in the middle of fts3Int.h ***************/
 /************** Begin file fts3_hash.h ***************************************/
 /*
 ** 2001 September 22
@@ -89953,8 +115617,8 @@ SQLITE_PRIVATE void sqlite3Fts3ExprInitTestInterface(sqlite3 *db);
 #define _FTS3_HASH_H_
 
 /* Forward declarations of structures. */
-typedef struct fts3Hash fts3Hash;
-typedef struct fts3HashElem fts3HashElem;
+typedef struct Fts3Hash Fts3Hash;
+typedef struct Fts3HashElem Fts3HashElem;
 
 /* A complete hash table is an instance of the following structure.
 ** The internals of this structure are intended to be opaque -- client
@@ -89964,15 +115628,15 @@ typedef struct fts3HashElem fts3HashElem;
 ** accessing this structure are really macros, so we can't really make
 ** this structure opaque.
 */
-struct fts3Hash {
+struct Fts3Hash {
   char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
   char copyKey;           /* True if copy of key made on insert */
   int count;              /* Number of entries in this table */
-  fts3HashElem *first;    /* The first element of the array */
+  Fts3HashElem *first;    /* The first element of the array */
   int htsize;             /* Number of buckets in the hash table */
   struct _fts3ht {        /* the hash table */
     int count;               /* Number of entries with this hash */
-    fts3HashElem *chain;     /* Pointer to first entry with this hash */
+    Fts3HashElem *chain;     /* Pointer to first entry with this hash */
   } *ht;
 };
 
@@ -89982,8 +115646,8 @@ struct fts3Hash {
 ** Again, this structure is intended to be opaque, but it can't really
 ** be opaque because it is used by macros.
 */
-struct fts3HashElem {
-  fts3HashElem *next, *prev; /* Next and previous elements in the table */
+struct Fts3HashElem {
+  Fts3HashElem *next, *prev; /* Next and previous elements in the table */
   void *data;                /* Data associated with this element */
   void *pKey; int nKey;      /* Key associated with this element */
 };
@@ -90006,25 +115670,27 @@ struct fts3HashElem {
 /*
 ** Access routines.  To delete, insert a NULL pointer.
 */
-SQLITE_PRIVATE void sqlite3Fts3HashInit(fts3Hash*, int keytype, int copyKey);
-SQLITE_PRIVATE void *sqlite3Fts3HashInsert(fts3Hash*, const void *pKey, int nKey, void *pData);
-SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash*, const void *pKey, int nKey);
-SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash*);
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey);
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(Fts3Hash*, const void *pKey, int nKey, void *pData);
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash*);
+SQLITE_PRIVATE Fts3HashElem *sqlite3Fts3HashFindElem(const Fts3Hash *, const void *, int);
 
 /*
 ** Shorthand for the functions above
 */
-#define fts3HashInit   sqlite3Fts3HashInit
-#define fts3HashInsert sqlite3Fts3HashInsert
-#define fts3HashFind   sqlite3Fts3HashFind
-#define fts3HashClear  sqlite3Fts3HashClear
+#define fts3HashInit     sqlite3Fts3HashInit
+#define fts3HashInsert   sqlite3Fts3HashInsert
+#define fts3HashFind     sqlite3Fts3HashFind
+#define fts3HashClear    sqlite3Fts3HashClear
+#define fts3HashFindElem sqlite3Fts3HashFindElem
 
 /*
 ** Macros for looping over all elements of a hash table.  The idiom is
 ** like this:
 **
-**   fts3Hash h;
-**   fts3HashElem *p;
+**   Fts3Hash h;
+**   Fts3HashElem *p;
 **   ...
 **   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
 **     SomeStructure *pData = fts3HashData(p);
@@ -90045,105 +115711,558 @@ SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash*);
 #endif /* _FTS3_HASH_H_ */
 
 /************** End of fts3_hash.h *******************************************/
+/************** Continuing where we left off in fts3Int.h ********************/
+
+/*
+** This constant controls how often segments are merged. Once there are
+** FTS3_MERGE_COUNT segments of level N, they are merged into a single
+** segment of level N+1.
+*/
+#define FTS3_MERGE_COUNT 16
+
+/*
+** This is the maximum amount of data (in bytes) to store in the 
+** Fts3Table.pendingTerms hash table. Normally, the hash table is
+** populated as documents are inserted/updated/deleted in a transaction
+** and used to create a new segment when the transaction is committed.
+** However if this limit is reached midway through a transaction, a new 
+** segment is created and the hash table cleared immediately.
+*/
+#define FTS3_MAX_PENDING_DATA (1*1024*1024)
+
+/*
+** Macro to return the number of elements in an array. SQLite has a
+** similar macro called ArraySize(). Use a different name to avoid
+** a collision when building an amalgamation with built-in FTS3.
+*/
+#define SizeofArray(X) ((int)(sizeof(X)/sizeof(X[0])))
+
+
+#ifndef MIN
+# define MIN(x,y) ((x)<(y)?(x):(y))
+#endif
+#ifndef MAX
+# define MAX(x,y) ((x)>(y)?(x):(y))
+#endif
+
+/*
+** Maximum length of a varint encoded integer. The varint format is different
+** from that used by SQLite, so the maximum length is 10, not 9.
+*/
+#define FTS3_VARINT_MAX 10
+
+/*
+** FTS4 virtual tables may maintain multiple indexes - one index of all terms
+** in the document set and zero or more prefix indexes. All indexes are stored
+** as one or more b+-trees in the %_segments and %_segdir tables. 
+**
+** It is possible to determine which index a b+-tree belongs to based on the
+** value stored in the "%_segdir.level" column. Given this value L, the index
+** that the b+-tree belongs to is (L<<10). In other words, all b+-trees with
+** level values between 0 and 1023 (inclusive) belong to index 0, all levels
+** between 1024 and 2047 to index 1, and so on.
+**
+** It is considered impossible for an index to use more than 1024 levels. In 
+** theory though this may happen, but only after at least 
+** (FTS3_MERGE_COUNT^1024) separate flushes of the pending-terms tables.
+*/
+#define FTS3_SEGDIR_MAXLEVEL      1024
+#define FTS3_SEGDIR_MAXLEVEL_STR "1024"
+
+/*
+** The testcase() macro is only used by the amalgamation.  If undefined,
+** make it a no-op.
+*/
+#ifndef testcase
+# define testcase(X)
+#endif
+
+/*
+** Terminator values for position-lists and column-lists.
+*/
+#define POS_COLUMN  (1)     /* Column-list terminator */
+#define POS_END     (0)     /* Position-list terminator */ 
+
+/*
+** This section provides definitions to allow the
+** FTS3 extension to be compiled outside of the 
+** amalgamation.
+*/
+#ifndef SQLITE_AMALGAMATION
+/*
+** Macros indicating that conditional expressions are always true or
+** false.
+*/
+#ifdef SQLITE_COVERAGE_TEST
+# define ALWAYS(x) (1)
+# define NEVER(X)  (0)
+#else
+# define ALWAYS(x) (x)
+# define NEVER(x)  (x)
+#endif
+
+/*
+** Internal types used by SQLite.
+*/
+typedef unsigned char u8;         /* 1-byte (or larger) unsigned integer */
+typedef short int i16;            /* 2-byte (or larger) signed integer */
+typedef unsigned int u32;         /* 4-byte unsigned integer */
+typedef sqlite3_uint64 u64;       /* 8-byte unsigned integer */
+typedef sqlite3_int64 i64;        /* 8-byte signed integer */
+
+/*
+** Macro used to suppress compiler warnings for unused parameters.
+*/
+#define UNUSED_PARAMETER(x) (void)(x)
+
+/*
+** Activate assert() only if SQLITE_TEST is enabled.
+*/
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG) 
+# define NDEBUG 1
+#endif
+
+/*
+** The TESTONLY macro is used to enclose variable declarations or
+** other bits of code that are needed to support the arguments
+** within testcase() and assert() macros.
+*/
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+# define TESTONLY(X)  X
+#else
+# define TESTONLY(X)
+#endif
+
+#endif /* SQLITE_AMALGAMATION */
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3Fts3Corrupt(void);
+# define FTS_CORRUPT_VTAB sqlite3Fts3Corrupt()
+#else
+# define FTS_CORRUPT_VTAB SQLITE_CORRUPT_VTAB
+#endif
+
+typedef struct Fts3Table Fts3Table;
+typedef struct Fts3Cursor Fts3Cursor;
+typedef struct Fts3Expr Fts3Expr;
+typedef struct Fts3Phrase Fts3Phrase;
+typedef struct Fts3PhraseToken Fts3PhraseToken;
+
+typedef struct Fts3Doclist Fts3Doclist;
+typedef struct Fts3SegFilter Fts3SegFilter;
+typedef struct Fts3DeferredToken Fts3DeferredToken;
+typedef struct Fts3SegReader Fts3SegReader;
+typedef struct Fts3MultiSegReader Fts3MultiSegReader;
+
+/*
+** A connection to a fulltext index is an instance of the following
+** structure. The xCreate and xConnect methods create an instance
+** of this structure and xDestroy and xDisconnect free that instance.
+** All other methods receive a pointer to the structure as one of their
+** arguments.
+*/
+struct Fts3Table {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  sqlite3 *db;                    /* The database connection */
+  const char *zDb;                /* logical database name */
+  const char *zName;              /* virtual table name */
+  int nColumn;                    /* number of named columns in virtual table */
+  char **azColumn;                /* column names.  malloced */
+  sqlite3_tokenizer *pTokenizer;  /* tokenizer for inserts and queries */
+  char *zContentTbl;              /* content=xxx option, or NULL */
+  char *zLanguageid;              /* languageid=xxx option, or NULL */
+  u8 bAutoincrmerge;              /* True if automerge=1 */
+  u32 nLeafAdd;                   /* Number of leaf blocks added this trans */
+
+  /* Precompiled statements used by the implementation. Each of these 
+  ** statements is run and reset within a single virtual table API call. 
+  */
+  sqlite3_stmt *aStmt[37];
+
+  char *zReadExprlist;
+  char *zWriteExprlist;
+
+  int nNodeSize;                  /* Soft limit for node size */
+  u8 bFts4;                       /* True for FTS4, false for FTS3 */
+  u8 bHasStat;                    /* True if %_stat table exists */
+  u8 bHasDocsize;                 /* True if %_docsize table exists */
+  u8 bDescIdx;                    /* True if doclists are in reverse order */
+  u8 bIgnoreSavepoint;            /* True to ignore xSavepoint invocations */
+  int nPgsz;                      /* Page size for host database */
+  char *zSegmentsTbl;             /* Name of %_segments table */
+  sqlite3_blob *pSegments;        /* Blob handle open on %_segments table */
+
+  /* 
+  ** The following array of hash tables is used to buffer pending index 
+  ** updates during transactions. All pending updates buffered at any one
+  ** time must share a common language-id (see the FTS4 langid= feature).
+  ** The current language id is stored in variable iPrevLangid.
+  **
+  ** A single FTS4 table may have multiple full-text indexes. For each index
+  ** there is an entry in the aIndex[] array. Index 0 is an index of all the
+  ** terms that appear in the document set. Each subsequent index in aIndex[]
+  ** is an index of prefixes of a specific length.
+  **
+  ** Variable nPendingData contains an estimate the memory consumed by the 
+  ** pending data structures, including hash table overhead, but not including
+  ** malloc overhead.  When nPendingData exceeds nMaxPendingData, all hash
+  ** tables are flushed to disk. Variable iPrevDocid is the docid of the most 
+  ** recently inserted record.
+  */
+  int nIndex;                     /* Size of aIndex[] */
+  struct Fts3Index {
+    int nPrefix;                  /* Prefix length (0 for main terms index) */
+    Fts3Hash hPending;            /* Pending terms table for this index */
+  } *aIndex;
+  int nMaxPendingData;            /* Max pending data before flush to disk */
+  int nPendingData;               /* Current bytes of pending data */
+  sqlite_int64 iPrevDocid;        /* Docid of most recently inserted document */
+  int iPrevLangid;                /* Langid of recently inserted document */
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+  /* State variables used for validating that the transaction control
+  ** methods of the virtual table are called at appropriate times.  These
+  ** values do not contribute to FTS functionality; they are used for
+  ** verifying the operation of the SQLite core.
+  */
+  int inTransaction;     /* True after xBegin but before xCommit/xRollback */
+  int mxSavepoint;       /* Largest valid xSavepoint integer */
+#endif
+};
+
+/*
+** When the core wants to read from the virtual table, it creates a
+** virtual table cursor (an instance of the following structure) using
+** the xOpen method. Cursors are destroyed using the xClose method.
+*/
+struct Fts3Cursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  i16 eSearch;                    /* Search strategy (see below) */
+  u8 isEof;                       /* True if at End Of Results */
+  u8 isRequireSeek;               /* True if must seek pStmt to %_content row */
+  sqlite3_stmt *pStmt;            /* Prepared statement in use by the cursor */
+  Fts3Expr *pExpr;                /* Parsed MATCH query string */
+  int iLangid;                    /* Language being queried for */
+  int nPhrase;                    /* Number of matchable phrases in query */
+  Fts3DeferredToken *pDeferred;   /* Deferred search tokens, if any */
+  sqlite3_int64 iPrevId;          /* Previous id read from aDoclist */
+  char *pNextId;                  /* Pointer into the body of aDoclist */
+  char *aDoclist;                 /* List of docids for full-text queries */
+  int nDoclist;                   /* Size of buffer at aDoclist */
+  u8 bDesc;                       /* True to sort in descending order */
+  int eEvalmode;                  /* An FTS3_EVAL_XX constant */
+  int nRowAvg;                    /* Average size of database rows, in pages */
+  sqlite3_int64 nDoc;             /* Documents in table */
+
+  int isMatchinfoNeeded;          /* True when aMatchinfo[] needs filling in */
+  u32 *aMatchinfo;                /* Information about most recent match */
+  int nMatchinfo;                 /* Number of elements in aMatchinfo[] */
+  char *zMatchinfo;               /* Matchinfo specification */
+};
+
+#define FTS3_EVAL_FILTER    0
+#define FTS3_EVAL_NEXT      1
+#define FTS3_EVAL_MATCHINFO 2
+
+/*
+** The Fts3Cursor.eSearch member is always set to one of the following.
+** Actualy, Fts3Cursor.eSearch can be greater than or equal to
+** FTS3_FULLTEXT_SEARCH.  If so, then Fts3Cursor.eSearch - 2 is the index
+** of the column to be searched.  For example, in
+**
+**     CREATE VIRTUAL TABLE ex1 USING fts3(a,b,c,d);
+**     SELECT docid FROM ex1 WHERE b MATCH 'one two three';
+** 
+** Because the LHS of the MATCH operator is 2nd column "b",
+** Fts3Cursor.eSearch will be set to FTS3_FULLTEXT_SEARCH+1.  (+0 for a,
+** +1 for b, +2 for c, +3 for d.)  If the LHS of MATCH were "ex1" 
+** indicating that all columns should be searched,
+** then eSearch would be set to FTS3_FULLTEXT_SEARCH+4.
+*/
+#define FTS3_FULLSCAN_SEARCH 0    /* Linear scan of %_content table */
+#define FTS3_DOCID_SEARCH    1    /* Lookup by rowid on %_content table */
+#define FTS3_FULLTEXT_SEARCH 2    /* Full-text index search */
+
+
+struct Fts3Doclist {
+  char *aAll;                    /* Array containing doclist (or NULL) */
+  int nAll;                      /* Size of a[] in bytes */
+  char *pNextDocid;              /* Pointer to next docid */
+
+  sqlite3_int64 iDocid;          /* Current docid (if pList!=0) */
+  int bFreeList;                 /* True if pList should be sqlite3_free()d */
+  char *pList;                   /* Pointer to position list following iDocid */
+  int nList;                     /* Length of position list */
+};
+
+/*
+** A "phrase" is a sequence of one or more tokens that must match in
+** sequence.  A single token is the base case and the most common case.
+** For a sequence of tokens contained in double-quotes (i.e. "one two three")
+** nToken will be the number of tokens in the string.
+*/
+struct Fts3PhraseToken {
+  char *z;                        /* Text of the token */
+  int n;                          /* Number of bytes in buffer z */
+  int isPrefix;                   /* True if token ends with a "*" character */
+  int bFirst;                     /* True if token must appear at position 0 */
+
+  /* Variables above this point are populated when the expression is
+  ** parsed (by code in fts3_expr.c). Below this point the variables are
+  ** used when evaluating the expression. */
+  Fts3DeferredToken *pDeferred;   /* Deferred token object for this token */
+  Fts3MultiSegReader *pSegcsr;    /* Segment-reader for this token */
+};
+
+struct Fts3Phrase {
+  /* Cache of doclist for this phrase. */
+  Fts3Doclist doclist;
+  int bIncr;                 /* True if doclist is loaded incrementally */
+  int iDoclistToken;
+
+  /* Variables below this point are populated by fts3_expr.c when parsing 
+  ** a MATCH expression. Everything above is part of the evaluation phase. 
+  */
+  int nToken;                /* Number of tokens in the phrase */
+  int iColumn;               /* Index of column this phrase must match */
+  Fts3PhraseToken aToken[1]; /* One entry for each token in the phrase */
+};
+
+/*
+** A tree of these objects forms the RHS of a MATCH operator.
+**
+** If Fts3Expr.eType is FTSQUERY_PHRASE and isLoaded is true, then aDoclist 
+** points to a malloced buffer, size nDoclist bytes, containing the results 
+** of this phrase query in FTS3 doclist format. As usual, the initial 
+** "Length" field found in doclists stored on disk is omitted from this 
+** buffer.
+**
+** Variable aMI is used only for FTSQUERY_NEAR nodes to store the global
+** matchinfo data. If it is not NULL, it points to an array of size nCol*3,
+** where nCol is the number of columns in the queried FTS table. The array
+** is populated as follows:
+**
+**   aMI[iCol*3 + 0] = Undefined
+**   aMI[iCol*3 + 1] = Number of occurrences
+**   aMI[iCol*3 + 2] = Number of rows containing at least one instance
+**
+** The aMI array is allocated using sqlite3_malloc(). It should be freed 
+** when the expression node is.
+*/
+struct Fts3Expr {
+  int eType;                 /* One of the FTSQUERY_XXX values defined below */
+  int nNear;                 /* Valid if eType==FTSQUERY_NEAR */
+  Fts3Expr *pParent;         /* pParent->pLeft==this or pParent->pRight==this */
+  Fts3Expr *pLeft;           /* Left operand */
+  Fts3Expr *pRight;          /* Right operand */
+  Fts3Phrase *pPhrase;       /* Valid if eType==FTSQUERY_PHRASE */
+
+  /* The following are used by the fts3_eval.c module. */
+  sqlite3_int64 iDocid;      /* Current docid */
+  u8 bEof;                   /* True this expression is at EOF already */
+  u8 bStart;                 /* True if iDocid is valid */
+  u8 bDeferred;              /* True if this expression is entirely deferred */
+
+  u32 *aMI;
+};
+
+/*
+** Candidate values for Fts3Query.eType. Note that the order of the first
+** four values is in order of precedence when parsing expressions. For 
+** example, the following:
+**
+**   "a OR b AND c NOT d NEAR e"
+**
+** is equivalent to:
+**
+**   "a OR (b AND (c NOT (d NEAR e)))"
+*/
+#define FTSQUERY_NEAR   1
+#define FTSQUERY_NOT    2
+#define FTSQUERY_AND    3
+#define FTSQUERY_OR     4
+#define FTSQUERY_PHRASE 5
+
+
+/* fts3_write.c */
+SQLITE_PRIVATE int sqlite3Fts3UpdateMethod(sqlite3_vtab*,int,sqlite3_value**,sqlite3_int64*);
+SQLITE_PRIVATE int sqlite3Fts3PendingTermsFlush(Fts3Table *);
+SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3Optimize(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderNew(int, int, sqlite3_int64,
+  sqlite3_int64, sqlite3_int64, const char *, int, Fts3SegReader**);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderPending(
+  Fts3Table*,int,const char*,int,int,Fts3SegReader**);
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFree(Fts3SegReader *);
+SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(Fts3Table*, int, int, int, sqlite3_stmt **);
+SQLITE_PRIVATE int sqlite3Fts3ReadLock(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3ReadBlock(Fts3Table*, sqlite3_int64, char **, int*, int*);
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDoctotal(Fts3Table *, sqlite3_stmt **);
+SQLITE_PRIVATE int sqlite3Fts3SelectDocsize(Fts3Table *, sqlite3_int64, sqlite3_stmt **);
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *);
+SQLITE_PRIVATE int sqlite3Fts3DeferToken(Fts3Cursor *, Fts3PhraseToken *, int);
+SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *);
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *);
+SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(Fts3DeferredToken *, char **, int *);
+#else
+# define sqlite3Fts3FreeDeferredTokens(x)
+# define sqlite3Fts3DeferToken(x,y,z) SQLITE_OK
+# define sqlite3Fts3CacheDeferredDoclists(x) SQLITE_OK
+# define sqlite3Fts3FreeDeferredDoclists(x)
+# define sqlite3Fts3DeferredTokenList(x,y,z) SQLITE_OK
+#endif
+
+SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3MaxLevel(Fts3Table *, int *);
+
+/* Special values interpreted by sqlite3SegReaderCursor() */
+#define FTS3_SEGCURSOR_PENDING        -1
+#define FTS3_SEGCURSOR_ALL            -2
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStart(Fts3Table*, Fts3MultiSegReader*, Fts3SegFilter*);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStep(Fts3Table *, Fts3MultiSegReader *);
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFinish(Fts3MultiSegReader *);
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderCursor(Fts3Table *, 
+    int, int, int, const char *, int, int, int, Fts3MultiSegReader *);
+
+/* Flags allowed as part of the 4th argument to SegmentReaderIterate() */
+#define FTS3_SEGMENT_REQUIRE_POS   0x00000001
+#define FTS3_SEGMENT_IGNORE_EMPTY  0x00000002
+#define FTS3_SEGMENT_COLUMN_FILTER 0x00000004
+#define FTS3_SEGMENT_PREFIX        0x00000008
+#define FTS3_SEGMENT_SCAN          0x00000010
+#define FTS3_SEGMENT_FIRST         0x00000020
+
+/* Type passed as 4th argument to SegmentReaderIterate() */
+struct Fts3SegFilter {
+  const char *zTerm;
+  int nTerm;
+  int iCol;
+  int flags;
+};
+
+struct Fts3MultiSegReader {
+  /* Used internally by sqlite3Fts3SegReaderXXX() calls */
+  Fts3SegReader **apSegment;      /* Array of Fts3SegReader objects */
+  int nSegment;                   /* Size of apSegment array */
+  int nAdvance;                   /* How many seg-readers to advance */
+  Fts3SegFilter *pFilter;         /* Pointer to filter object */
+  char *aBuffer;                  /* Buffer to merge doclists in */
+  int nBuffer;                    /* Allocated size of aBuffer[] in bytes */
+
+  int iColFilter;                 /* If >=0, filter for this column */
+  int bRestart;
+
+  /* Used by fts3.c only. */
+  int nCost;                      /* Cost of running iterator */
+  int bLookup;                    /* True if a lookup of a single entry. */
+
+  /* Output values. Valid only after Fts3SegReaderStep() returns SQLITE_ROW. */
+  char *zTerm;                    /* Pointer to term buffer */
+  int nTerm;                      /* Size of zTerm in bytes */
+  char *aDoclist;                 /* Pointer to doclist buffer */
+  int nDoclist;                   /* Size of aDoclist[] in bytes */
+};
+
+SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table*,int,int);
+
+/* fts3.c */
+SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *, sqlite3_int64);
+SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
+SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *, int *);
+SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64);
+SQLITE_PRIVATE void sqlite3Fts3Dequote(char *);
+SQLITE_PRIVATE void sqlite3Fts3DoclistPrev(int,char*,int,char**,sqlite3_int64*,int*,u8*);
+SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(Fts3Cursor *, Fts3Expr *, u32 *);
+SQLITE_PRIVATE int sqlite3Fts3FirstFilter(sqlite3_int64, char *, int, char *);
+SQLITE_PRIVATE void sqlite3Fts3CreateStatTable(int*, Fts3Table*);
+
+/* fts3_tokenizer.c */
+SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *, int *);
+SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
+SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(Fts3Hash *pHash, const char *, 
+    sqlite3_tokenizer **, char **
+);
+SQLITE_PRIVATE int sqlite3Fts3IsIdChar(char);
+
+/* fts3_snippet.c */
+SQLITE_PRIVATE void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);
+SQLITE_PRIVATE void sqlite3Fts3Snippet(sqlite3_context *, Fts3Cursor *, const char *,
+  const char *, const char *, int, int
+);
+SQLITE_PRIVATE void sqlite3Fts3Matchinfo(sqlite3_context *, Fts3Cursor *, const char *);
+
+/* fts3_expr.c */
+SQLITE_PRIVATE int sqlite3Fts3ExprParse(sqlite3_tokenizer *, int,
+  char **, int, int, int, const char *, int, Fts3Expr **
+);
+SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *);
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3Fts3ExprInitTestInterface(sqlite3 *db);
+SQLITE_PRIVATE int sqlite3Fts3InitTerm(sqlite3 *db);
+#endif
+
+SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(sqlite3_tokenizer *, int, const char *, int,
+  sqlite3_tokenizer_cursor **
+);
+
+/* fts3_aux.c */
+SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db);
+
+SQLITE_PRIVATE void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *);
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrStart(
+    Fts3Table*, Fts3MultiSegReader*, int, const char*, int);
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
+    Fts3Table *, Fts3MultiSegReader *, sqlite3_int64 *, char **, int *);
+SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(Fts3Cursor *, Fts3Expr *, int iCol, char **); 
+SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr);
+
+/* fts3_unicode2.c (functions generated by parsing unicode text files) */
+#ifdef SQLITE_ENABLE_FTS4_UNICODE61
+SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int, int);
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int);
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int);
+#endif
+
+#endif /* !SQLITE_CORE || SQLITE_ENABLE_FTS3 */
+#endif /* _FTSINT_H */
+
+/************** End of fts3Int.h *********************************************/
 /************** Continuing where we left off in fts3.c ***********************/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
+# define SQLITE_CORE 1
+#endif
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stddef.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+/* #include <stdarg.h> */
+
 #ifndef SQLITE_CORE 
   SQLITE_EXTENSION_INIT1
 #endif
 
+static int fts3EvalNext(Fts3Cursor *pCsr);
+static int fts3EvalStart(Fts3Cursor *pCsr);
+static int fts3TermSegReaderCursor(
+    Fts3Cursor *, const char *, int, int, Fts3MultiSegReader **);
 
-/* TODO(shess) MAN, this thing needs some refactoring.  At minimum, it
-** would be nice to order the file better, perhaps something along the
-** lines of:
-**
-**  - utility functions
-**  - table setup functions
-**  - table update functions
-**  - table query functions
-**
-** Put the query functions last because they're likely to reference
-** typedefs or functions from the table update section.
+/* 
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data written will be between 1 and FTS3_VARINT_MAX bytes.
+** The number of bytes written is returned.
 */
-
-#if 0
-# define FTSTRACE(A)  printf A; fflush(stdout)
-#else
-# define FTSTRACE(A)
-#endif
-
-/* It is not safe to call isspace(), tolower(), or isalnum() on
-** hi-bit-set characters.  This is the same solution used in the
-** tokenizer.
-*/
-/* TODO(shess) The snippet-generation code should be using the
-** tokenizer-generated tokens rather than doing its own local
-** tokenization.
-*/
-/* TODO(shess) Is __isascii() a portable version of (c&0x80)==0? */
-static int safe_isspace(char c){
-  return (c&0x80)==0 ? isspace(c) : 0;
-}
-static int safe_tolower(char c){
-  return (c&0x80)==0 ? tolower(c) : c;
-}
-static int safe_isalnum(char c){
-  return (c&0x80)==0 ? isalnum(c) : 0;
-}
-
-typedef enum DocListType {
-  DL_DOCIDS,              /* docids only */
-  DL_POSITIONS,           /* docids + positions */
-  DL_POSITIONS_OFFSETS    /* docids + positions + offsets */
-} DocListType;
-
-/*
-** By default, only positions and not offsets are stored in the doclists.
-** To change this so that offsets are stored too, compile with
-**
-**          -DDL_DEFAULT=DL_POSITIONS_OFFSETS
-**
-** If DL_DEFAULT is set to DL_DOCIDS, your table can only be inserted
-** into (no deletes or updates).
-*/
-#ifndef DL_DEFAULT
-# define DL_DEFAULT DL_POSITIONS
-#endif
-
-enum {
-  POS_END = 0,        /* end of this position list */
-  POS_COLUMN,         /* followed by new column number */
-  POS_BASE
-};
-
-/* MERGE_COUNT controls how often we merge segments (see comment at
-** top of file).
-*/
-#define MERGE_COUNT 16
-
-/* utility functions */
-
-/* CLEAR() and SCRAMBLE() abstract memset() on a pointer to a single
-** record to prevent errors of the form:
-**
-** my_function(SomeType *b){
-**   memset(b, '\0', sizeof(b));  // sizeof(b)!=sizeof(*b)
-** }
-*/
-/* TODO(shess) Obvious candidates for a header file. */
-#define CLEAR(b) memset(b, '\0', sizeof(*(b)))
-
-#ifndef NDEBUG
-#  define SCRAMBLE(b) memset(b, 0x55, sizeof(*(b)))
-#else
-#  define SCRAMBLE(b)
-#endif
-
-/* We may need up to VARINT_MAX bytes to store an encoded 64-bit integer. */
-#define VARINT_MAX 10
-
-/* Write a 64-bit variable-length integer to memory starting at p[0].
- * The length of data written will be between 1 and VARINT_MAX bytes.
- * The number of bytes written is returned. */
-static int fts3PutVarint(char *p, sqlite_int64 v){
+SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){
   unsigned char *q = (unsigned char *) p;
   sqlite_uint64 vu = v;
   do{
@@ -90151,2207 +116270,48 @@ static int fts3PutVarint(char *p, sqlite_int64 v){
     vu >>= 7;
   }while( vu!=0 );
   q[-1] &= 0x7f;  /* turn off high bit in final byte */
-  assert( q - (unsigned char *)p <= VARINT_MAX );
+  assert( q - (unsigned char *)p <= FTS3_VARINT_MAX );
   return (int) (q - (unsigned char *)p);
 }
 
-/* Read a 64-bit variable-length integer from memory starting at p[0].
- * Return the number of bytes read, or 0 on error.
- * The value is stored in *v. */
-static int fts3GetVarint(const char *p, sqlite_int64 *v){
+/* 
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read, or 0 on error.
+** The value is stored in *v.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *p, sqlite_int64 *v){
   const unsigned char *q = (const unsigned char *) p;
   sqlite_uint64 x = 0, y = 1;
-  while( (*q & 0x80) == 0x80 ){
+  while( (*q&0x80)==0x80 && q-(unsigned char *)p<FTS3_VARINT_MAX ){
     x += y * (*q++ & 0x7f);
     y <<= 7;
-    if( q - (unsigned char *)p >= VARINT_MAX ){  /* bad data */
-      assert( 0 );
-      return 0;
-    }
   }
   x += y * (*q++);
   *v = (sqlite_int64) x;
   return (int) (q - (unsigned char *)p);
 }
 
-static int fts3GetVarint32(const char *p, int *pi){
+/*
+** Similar to sqlite3Fts3GetVarint(), except that the output is truncated to a
+** 32-bit integer before it is returned.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *p, int *pi){
  sqlite_int64 i;
- int ret = fts3GetVarint(p, &i);
+ int ret = sqlite3Fts3GetVarint(p, &i);
  *pi = (int) i;
- assert( *pi==i );
  return ret;
 }
 
-/*******************************************************************/
-/* DataBuffer is used to collect data into a buffer in piecemeal
-** fashion.  It implements the usual distinction between amount of
-** data currently stored (nData) and buffer capacity (nCapacity).
-**
-** dataBufferInit - create a buffer with given initial capacity.
-** dataBufferReset - forget buffer's data, retaining capacity.
-** dataBufferDestroy - free buffer's data.
-** dataBufferSwap - swap contents of two buffers.
-** dataBufferExpand - expand capacity without adding data.
-** dataBufferAppend - append data.
-** dataBufferAppend2 - append two pieces of data at once.
-** dataBufferReplace - replace buffer's data.
-*/
-typedef struct DataBuffer {
-  char *pData;          /* Pointer to malloc'ed buffer. */
-  int nCapacity;        /* Size of pData buffer. */
-  int nData;            /* End of data loaded into pData. */
-} DataBuffer;
-
-static void dataBufferInit(DataBuffer *pBuffer, int nCapacity){
-  assert( nCapacity>=0 );
-  pBuffer->nData = 0;
-  pBuffer->nCapacity = nCapacity;
-  pBuffer->pData = nCapacity==0 ? NULL : sqlite3_malloc(nCapacity);
-}
-static void dataBufferReset(DataBuffer *pBuffer){
-  pBuffer->nData = 0;
-}
-static void dataBufferDestroy(DataBuffer *pBuffer){
-  if( pBuffer->pData!=NULL ) sqlite3_free(pBuffer->pData);
-  SCRAMBLE(pBuffer);
-}
-static void dataBufferSwap(DataBuffer *pBuffer1, DataBuffer *pBuffer2){
-  DataBuffer tmp = *pBuffer1;
-  *pBuffer1 = *pBuffer2;
-  *pBuffer2 = tmp;
-}
-static void dataBufferExpand(DataBuffer *pBuffer, int nAddCapacity){
-  assert( nAddCapacity>0 );
-  /* TODO(shess) Consider expanding more aggressively.  Note that the
-  ** underlying malloc implementation may take care of such things for
-  ** us already.
-  */
-  if( pBuffer->nData+nAddCapacity>pBuffer->nCapacity ){
-    pBuffer->nCapacity = pBuffer->nData+nAddCapacity;
-    pBuffer->pData = sqlite3_realloc(pBuffer->pData, pBuffer->nCapacity);
-  }
-}
-static void dataBufferAppend(DataBuffer *pBuffer,
-                             const char *pSource, int nSource){
-  assert( nSource>0 && pSource!=NULL );
-  dataBufferExpand(pBuffer, nSource);
-  memcpy(pBuffer->pData+pBuffer->nData, pSource, nSource);
-  pBuffer->nData += nSource;
-}
-static void dataBufferAppend2(DataBuffer *pBuffer,
-                              const char *pSource1, int nSource1,
-                              const char *pSource2, int nSource2){
-  assert( nSource1>0 && pSource1!=NULL );
-  assert( nSource2>0 && pSource2!=NULL );
-  dataBufferExpand(pBuffer, nSource1+nSource2);
-  memcpy(pBuffer->pData+pBuffer->nData, pSource1, nSource1);
-  memcpy(pBuffer->pData+pBuffer->nData+nSource1, pSource2, nSource2);
-  pBuffer->nData += nSource1+nSource2;
-}
-static void dataBufferReplace(DataBuffer *pBuffer,
-                              const char *pSource, int nSource){
-  dataBufferReset(pBuffer);
-  dataBufferAppend(pBuffer, pSource, nSource);
-}
-
-/* StringBuffer is a null-terminated version of DataBuffer. */
-typedef struct StringBuffer {
-  DataBuffer b;            /* Includes null terminator. */
-} StringBuffer;
-
-static void initStringBuffer(StringBuffer *sb){
-  dataBufferInit(&sb->b, 100);
-  dataBufferReplace(&sb->b, "", 1);
-}
-static int stringBufferLength(StringBuffer *sb){
-  return sb->b.nData-1;
-}
-static char *stringBufferData(StringBuffer *sb){
-  return sb->b.pData;
-}
-static void stringBufferDestroy(StringBuffer *sb){
-  dataBufferDestroy(&sb->b);
-}
-
-static void nappend(StringBuffer *sb, const char *zFrom, int nFrom){
-  assert( sb->b.nData>0 );
-  if( nFrom>0 ){
-    sb->b.nData--;
-    dataBufferAppend2(&sb->b, zFrom, nFrom, "", 1);
-  }
-}
-static void append(StringBuffer *sb, const char *zFrom){
-  nappend(sb, zFrom, strlen(zFrom));
-}
-
-/* Append a list of strings separated by commas. */
-static void appendList(StringBuffer *sb, int nString, char **azString){
-  int i;
-  for(i=0; i<nString; ++i){
-    if( i>0 ) append(sb, ", ");
-    append(sb, azString[i]);
-  }
-}
-
-static int endsInWhiteSpace(StringBuffer *p){
-  return stringBufferLength(p)>0 &&
-    safe_isspace(stringBufferData(p)[stringBufferLength(p)-1]);
-}
-
-/* If the StringBuffer ends in something other than white space, add a
-** single space character to the end.
-*/
-static void appendWhiteSpace(StringBuffer *p){
-  if( stringBufferLength(p)==0 ) return;
-  if( !endsInWhiteSpace(p) ) append(p, " ");
-}
-
-/* Remove white space from the end of the StringBuffer */
-static void trimWhiteSpace(StringBuffer *p){
-  while( endsInWhiteSpace(p) ){
-    p->b.pData[--p->b.nData-1] = '\0';
-  }
-}
-
-/*******************************************************************/
-/* DLReader is used to read document elements from a doclist.  The
-** current docid is cached, so dlrDocid() is fast.  DLReader does not
-** own the doclist buffer.
-**
-** dlrAtEnd - true if there's no more data to read.
-** dlrDocid - docid of current document.
-** dlrDocData - doclist data for current document (including docid).
-** dlrDocDataBytes - length of same.
-** dlrAllDataBytes - length of all remaining data.
-** dlrPosData - position data for current document.
-** dlrPosDataLen - length of pos data for current document (incl POS_END).
-** dlrStep - step to current document.
-** dlrInit - initial for doclist of given type against given data.
-** dlrDestroy - clean up.
-**
-** Expected usage is something like:
-**
-**   DLReader reader;
-**   dlrInit(&reader, pData, nData);
-**   while( !dlrAtEnd(&reader) ){
-**     // calls to dlrDocid() and kin.
-**     dlrStep(&reader);
-**   }
-**   dlrDestroy(&reader);
-*/
-typedef struct DLReader {
-  DocListType iType;
-  const char *pData;
-  int nData;
-
-  sqlite_int64 iDocid;
-  int nElement;
-} DLReader;
-
-static int dlrAtEnd(DLReader *pReader){
-  assert( pReader->nData>=0 );
-  return pReader->nData==0;
-}
-static sqlite_int64 dlrDocid(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->iDocid;
-}
-static const char *dlrDocData(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->pData;
-}
-static int dlrDocDataBytes(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->nElement;
-}
-static int dlrAllDataBytes(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->nData;
-}
-/* TODO(shess) Consider adding a field to track iDocid varint length
-** to make these two functions faster.  This might matter (a tiny bit)
-** for queries.
-*/
-static const char *dlrPosData(DLReader *pReader){
-  sqlite_int64 iDummy;
-  int n = fts3GetVarint(pReader->pData, &iDummy);
-  assert( !dlrAtEnd(pReader) );
-  return pReader->pData+n;
-}
-static int dlrPosDataLen(DLReader *pReader){
-  sqlite_int64 iDummy;
-  int n = fts3GetVarint(pReader->pData, &iDummy);
-  assert( !dlrAtEnd(pReader) );
-  return pReader->nElement-n;
-}
-static void dlrStep(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-
-  /* Skip past current doclist element. */
-  assert( pReader->nElement<=pReader->nData );
-  pReader->pData += pReader->nElement;
-  pReader->nData -= pReader->nElement;
-
-  /* If there is more data, read the next doclist element. */
-  if( pReader->nData!=0 ){
-    sqlite_int64 iDocidDelta;
-    int iDummy, n = fts3GetVarint(pReader->pData, &iDocidDelta);
-    pReader->iDocid += iDocidDelta;
-    if( pReader->iType>=DL_POSITIONS ){
-      assert( n<pReader->nData );
-      while( 1 ){
-        n += fts3GetVarint32(pReader->pData+n, &iDummy);
-        assert( n<=pReader->nData );
-        if( iDummy==POS_END ) break;
-        if( iDummy==POS_COLUMN ){
-          n += fts3GetVarint32(pReader->pData+n, &iDummy);
-          assert( n<pReader->nData );
-        }else if( pReader->iType==DL_POSITIONS_OFFSETS ){
-          n += fts3GetVarint32(pReader->pData+n, &iDummy);
-          n += fts3GetVarint32(pReader->pData+n, &iDummy);
-          assert( n<pReader->nData );
-        }
-      }
-    }
-    pReader->nElement = n;
-    assert( pReader->nElement<=pReader->nData );
-  }
-}
-static void dlrInit(DLReader *pReader, DocListType iType,
-                    const char *pData, int nData){
-  assert( pData!=NULL && nData!=0 );
-  pReader->iType = iType;
-  pReader->pData = pData;
-  pReader->nData = nData;
-  pReader->nElement = 0;
-  pReader->iDocid = 0;
-
-  /* Load the first element's data.  There must be a first element. */
-  dlrStep(pReader);
-}
-static void dlrDestroy(DLReader *pReader){
-  SCRAMBLE(pReader);
-}
-
-#ifndef NDEBUG
-/* Verify that the doclist can be validly decoded.  Also returns the
-** last docid found because it is convenient in other assertions for
-** DLWriter.
-*/
-static void docListValidate(DocListType iType, const char *pData, int nData,
-                            sqlite_int64 *pLastDocid){
-  sqlite_int64 iPrevDocid = 0;
-  assert( nData>0 );
-  assert( pData!=0 );
-  assert( pData+nData>pData );
-  while( nData!=0 ){
-    sqlite_int64 iDocidDelta;
-    int n = fts3GetVarint(pData, &iDocidDelta);
-    iPrevDocid += iDocidDelta;
-    if( iType>DL_DOCIDS ){
-      int iDummy;
-      while( 1 ){
-        n += fts3GetVarint32(pData+n, &iDummy);
-        if( iDummy==POS_END ) break;
-        if( iDummy==POS_COLUMN ){
-          n += fts3GetVarint32(pData+n, &iDummy);
-        }else if( iType>DL_POSITIONS ){
-          n += fts3GetVarint32(pData+n, &iDummy);
-          n += fts3GetVarint32(pData+n, &iDummy);
-        }
-        assert( n<=nData );
-      }
-    }
-    assert( n<=nData );
-    pData += n;
-    nData -= n;
-  }
-  if( pLastDocid ) *pLastDocid = iPrevDocid;
-}
-#define ASSERT_VALID_DOCLIST(i, p, n, o) docListValidate(i, p, n, o)
-#else
-#define ASSERT_VALID_DOCLIST(i, p, n, o) assert( 1 )
-#endif
-
-/*******************************************************************/
-/* DLWriter is used to write doclist data to a DataBuffer.  DLWriter
-** always appends to the buffer and does not own it.
-**
-** dlwInit - initialize to write a given type doclistto a buffer.
-** dlwDestroy - clear the writer's memory.  Does not free buffer.
-** dlwAppend - append raw doclist data to buffer.
-** dlwCopy - copy next doclist from reader to writer.
-** dlwAdd - construct doclist element and append to buffer.
-**    Only apply dlwAdd() to DL_DOCIDS doclists (else use PLWriter).
-*/
-typedef struct DLWriter {
-  DocListType iType;
-  DataBuffer *b;
-  sqlite_int64 iPrevDocid;
-#ifndef NDEBUG
-  int has_iPrevDocid;
-#endif
-} DLWriter;
-
-static void dlwInit(DLWriter *pWriter, DocListType iType, DataBuffer *b){
-  pWriter->b = b;
-  pWriter->iType = iType;
-  pWriter->iPrevDocid = 0;
-#ifndef NDEBUG
-  pWriter->has_iPrevDocid = 0;
-#endif
-}
-static void dlwDestroy(DLWriter *pWriter){
-  SCRAMBLE(pWriter);
-}
-/* iFirstDocid is the first docid in the doclist in pData.  It is
-** needed because pData may point within a larger doclist, in which
-** case the first item would be delta-encoded.
-**
-** iLastDocid is the final docid in the doclist in pData.  It is
-** needed to create the new iPrevDocid for future delta-encoding.  The
-** code could decode the passed doclist to recreate iLastDocid, but
-** the only current user (docListMerge) already has decoded this
-** information.
-*/
-/* TODO(shess) This has become just a helper for docListMerge.
-** Consider a refactor to make this cleaner.
-*/
-static void dlwAppend(DLWriter *pWriter,
-                      const char *pData, int nData,
-                      sqlite_int64 iFirstDocid, sqlite_int64 iLastDocid){
-  sqlite_int64 iDocid = 0;
-  char c[VARINT_MAX];
-  int nFirstOld, nFirstNew;     /* Old and new varint len of first docid. */
-#ifndef NDEBUG
-  sqlite_int64 iLastDocidDelta;
-#endif
-
-  /* Recode the initial docid as delta from iPrevDocid. */
-  nFirstOld = fts3GetVarint(pData, &iDocid);
-  assert( nFirstOld<nData || (nFirstOld==nData && pWriter->iType==DL_DOCIDS) );
-  nFirstNew = fts3PutVarint(c, iFirstDocid-pWriter->iPrevDocid);
-
-  /* Verify that the incoming doclist is valid AND that it ends with
-  ** the expected docid.  This is essential because we'll trust this
-  ** docid in future delta-encoding.
-  */
-  ASSERT_VALID_DOCLIST(pWriter->iType, pData, nData, &iLastDocidDelta);
-  assert( iLastDocid==iFirstDocid-iDocid+iLastDocidDelta );
-
-  /* Append recoded initial docid and everything else.  Rest of docids
-  ** should have been delta-encoded from previous initial docid.
-  */
-  if( nFirstOld<nData ){
-    dataBufferAppend2(pWriter->b, c, nFirstNew,
-                      pData+nFirstOld, nData-nFirstOld);
-  }else{
-    dataBufferAppend(pWriter->b, c, nFirstNew);
-  }
-  pWriter->iPrevDocid = iLastDocid;
-}
-static void dlwCopy(DLWriter *pWriter, DLReader *pReader){
-  dlwAppend(pWriter, dlrDocData(pReader), dlrDocDataBytes(pReader),
-            dlrDocid(pReader), dlrDocid(pReader));
-}
-static void dlwAdd(DLWriter *pWriter, sqlite_int64 iDocid){
-  char c[VARINT_MAX];
-  int n = fts3PutVarint(c, iDocid-pWriter->iPrevDocid);
-
-  /* Docids must ascend. */
-  assert( !pWriter->has_iPrevDocid || iDocid>pWriter->iPrevDocid );
-  assert( pWriter->iType==DL_DOCIDS );
-
-  dataBufferAppend(pWriter->b, c, n);
-  pWriter->iPrevDocid = iDocid;
-#ifndef NDEBUG
-  pWriter->has_iPrevDocid = 1;
-#endif
-}
-
-/*******************************************************************/
-/* PLReader is used to read data from a document's position list.  As
-** the caller steps through the list, data is cached so that varints
-** only need to be decoded once.
-**
-** plrInit, plrDestroy - create/destroy a reader.
-** plrColumn, plrPosition, plrStartOffset, plrEndOffset - accessors
-** plrAtEnd - at end of stream, only call plrDestroy once true.
-** plrStep - step to the next element.
-*/
-typedef struct PLReader {
-  /* These refer to the next position's data.  nData will reach 0 when
-  ** reading the last position, so plrStep() signals EOF by setting
-  ** pData to NULL.
-  */
-  const char *pData;
-  int nData;
-
-  DocListType iType;
-  int iColumn;         /* the last column read */
-  int iPosition;       /* the last position read */
-  int iStartOffset;    /* the last start offset read */
-  int iEndOffset;      /* the last end offset read */
-} PLReader;
-
-static int plrAtEnd(PLReader *pReader){
-  return pReader->pData==NULL;
-}
-static int plrColumn(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iColumn;
-}
-static int plrPosition(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iPosition;
-}
-static int plrStartOffset(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iStartOffset;
-}
-static int plrEndOffset(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iEndOffset;
-}
-static void plrStep(PLReader *pReader){
-  int i, n;
-
-  assert( !plrAtEnd(pReader) );
-
-  if( pReader->nData==0 ){
-    pReader->pData = NULL;
-    return;
-  }
-
-  n = fts3GetVarint32(pReader->pData, &i);
-  if( i==POS_COLUMN ){
-    n += fts3GetVarint32(pReader->pData+n, &pReader->iColumn);
-    pReader->iPosition = 0;
-    pReader->iStartOffset = 0;
-    n += fts3GetVarint32(pReader->pData+n, &i);
-  }
-  /* Should never see adjacent column changes. */
-  assert( i!=POS_COLUMN );
-
-  if( i==POS_END ){
-    pReader->nData = 0;
-    pReader->pData = NULL;
-    return;
-  }
-
-  pReader->iPosition += i-POS_BASE;
-  if( pReader->iType==DL_POSITIONS_OFFSETS ){
-    n += fts3GetVarint32(pReader->pData+n, &i);
-    pReader->iStartOffset += i;
-    n += fts3GetVarint32(pReader->pData+n, &i);
-    pReader->iEndOffset = pReader->iStartOffset+i;
-  }
-  assert( n<=pReader->nData );
-  pReader->pData += n;
-  pReader->nData -= n;
-}
-
-static void plrInit(PLReader *pReader, DLReader *pDLReader){
-  pReader->pData = dlrPosData(pDLReader);
-  pReader->nData = dlrPosDataLen(pDLReader);
-  pReader->iType = pDLReader->iType;
-  pReader->iColumn = 0;
-  pReader->iPosition = 0;
-  pReader->iStartOffset = 0;
-  pReader->iEndOffset = 0;
-  plrStep(pReader);
-}
-static void plrDestroy(PLReader *pReader){
-  SCRAMBLE(pReader);
-}
-
-/*******************************************************************/
-/* PLWriter is used in constructing a document's position list.  As a
-** convenience, if iType is DL_DOCIDS, PLWriter becomes a no-op.
-** PLWriter writes to the associated DLWriter's buffer.
-**
-** plwInit - init for writing a document's poslist.
-** plwDestroy - clear a writer.
-** plwAdd - append position and offset information.
-** plwCopy - copy next position's data from reader to writer.
-** plwTerminate - add any necessary doclist terminator.
-**
-** Calling plwAdd() after plwTerminate() may result in a corrupt
-** doclist.
-*/
-/* TODO(shess) Until we've written the second item, we can cache the
-** first item's information.  Then we'd have three states:
-**
-** - initialized with docid, no positions.
-** - docid and one position.
-** - docid and multiple positions.
-**
-** Only the last state needs to actually write to dlw->b, which would
-** be an improvement in the DLCollector case.
-*/
-typedef struct PLWriter {
-  DLWriter *dlw;
-
-  int iColumn;    /* the last column written */
-  int iPos;       /* the last position written */
-  int iOffset;    /* the last start offset written */
-} PLWriter;
-
-/* TODO(shess) In the case where the parent is reading these values
-** from a PLReader, we could optimize to a copy if that PLReader has
-** the same type as pWriter.
-*/
-static void plwAdd(PLWriter *pWriter, int iColumn, int iPos,
-                   int iStartOffset, int iEndOffset){
-  /* Worst-case space for POS_COLUMN, iColumn, iPosDelta,
-  ** iStartOffsetDelta, and iEndOffsetDelta.
-  */
-  char c[5*VARINT_MAX];
-  int n = 0;
-
-  /* Ban plwAdd() after plwTerminate(). */
-  assert( pWriter->iPos!=-1 );
-
-  if( pWriter->dlw->iType==DL_DOCIDS ) return;
-
-  if( iColumn!=pWriter->iColumn ){
-    n += fts3PutVarint(c+n, POS_COLUMN);
-    n += fts3PutVarint(c+n, iColumn);
-    pWriter->iColumn = iColumn;
-    pWriter->iPos = 0;
-    pWriter->iOffset = 0;
-  }
-  assert( iPos>=pWriter->iPos );
-  n += fts3PutVarint(c+n, POS_BASE+(iPos-pWriter->iPos));
-  pWriter->iPos = iPos;
-  if( pWriter->dlw->iType==DL_POSITIONS_OFFSETS ){
-    assert( iStartOffset>=pWriter->iOffset );
-    n += fts3PutVarint(c+n, iStartOffset-pWriter->iOffset);
-    pWriter->iOffset = iStartOffset;
-    assert( iEndOffset>=iStartOffset );
-    n += fts3PutVarint(c+n, iEndOffset-iStartOffset);
-  }
-  dataBufferAppend(pWriter->dlw->b, c, n);
-}
-static void plwCopy(PLWriter *pWriter, PLReader *pReader){
-  plwAdd(pWriter, plrColumn(pReader), plrPosition(pReader),
-         plrStartOffset(pReader), plrEndOffset(pReader));
-}
-static void plwInit(PLWriter *pWriter, DLWriter *dlw, sqlite_int64 iDocid){
-  char c[VARINT_MAX];
-  int n;
-
-  pWriter->dlw = dlw;
-
-  /* Docids must ascend. */
-  assert( !pWriter->dlw->has_iPrevDocid || iDocid>pWriter->dlw->iPrevDocid );
-  n = fts3PutVarint(c, iDocid-pWriter->dlw->iPrevDocid);
-  dataBufferAppend(pWriter->dlw->b, c, n);
-  pWriter->dlw->iPrevDocid = iDocid;
-#ifndef NDEBUG
-  pWriter->dlw->has_iPrevDocid = 1;
-#endif
-
-  pWriter->iColumn = 0;
-  pWriter->iPos = 0;
-  pWriter->iOffset = 0;
-}
-/* TODO(shess) Should plwDestroy() also terminate the doclist?  But
-** then plwDestroy() would no longer be just a destructor, it would
-** also be doing work, which isn't consistent with the overall idiom.
-** Another option would be for plwAdd() to always append any necessary
-** terminator, so that the output is always correct.  But that would
-** add incremental work to the common case with the only benefit being
-** API elegance.  Punt for now.
-*/
-static void plwTerminate(PLWriter *pWriter){
-  if( pWriter->dlw->iType>DL_DOCIDS ){
-    char c[VARINT_MAX];
-    int n = fts3PutVarint(c, POS_END);
-    dataBufferAppend(pWriter->dlw->b, c, n);
-  }
-#ifndef NDEBUG
-  /* Mark as terminated for assert in plwAdd(). */
-  pWriter->iPos = -1;
-#endif
-}
-static void plwDestroy(PLWriter *pWriter){
-  SCRAMBLE(pWriter);
-}
-
-/*******************************************************************/
-/* DLCollector wraps PLWriter and DLWriter to provide a
-** dynamically-allocated doclist area to use during tokenization.
-**
-** dlcNew - malloc up and initialize a collector.
-** dlcDelete - destroy a collector and all contained items.
-** dlcAddPos - append position and offset information.
-** dlcAddDoclist - add the collected doclist to the given buffer.
-** dlcNext - terminate the current document and open another.
-*/
-typedef struct DLCollector {
-  DataBuffer b;
-  DLWriter dlw;
-  PLWriter plw;
-} DLCollector;
-
-/* TODO(shess) This could also be done by calling plwTerminate() and
-** dataBufferAppend().  I tried that, expecting nominal performance
-** differences, but it seemed to pretty reliably be worth 1% to code
-** it this way.  I suspect it is the incremental malloc overhead (some
-** percentage of the plwTerminate() calls will cause a realloc), so
-** this might be worth revisiting if the DataBuffer implementation
-** changes.
-*/
-static void dlcAddDoclist(DLCollector *pCollector, DataBuffer *b){
-  if( pCollector->dlw.iType>DL_DOCIDS ){
-    char c[VARINT_MAX];
-    int n = fts3PutVarint(c, POS_END);
-    dataBufferAppend2(b, pCollector->b.pData, pCollector->b.nData, c, n);
-  }else{
-    dataBufferAppend(b, pCollector->b.pData, pCollector->b.nData);
-  }
-}
-static void dlcNext(DLCollector *pCollector, sqlite_int64 iDocid){
-  plwTerminate(&pCollector->plw);
-  plwDestroy(&pCollector->plw);
-  plwInit(&pCollector->plw, &pCollector->dlw, iDocid);
-}
-static void dlcAddPos(DLCollector *pCollector, int iColumn, int iPos,
-                      int iStartOffset, int iEndOffset){
-  plwAdd(&pCollector->plw, iColumn, iPos, iStartOffset, iEndOffset);
-}
-
-static DLCollector *dlcNew(sqlite_int64 iDocid, DocListType iType){
-  DLCollector *pCollector = sqlite3_malloc(sizeof(DLCollector));
-  dataBufferInit(&pCollector->b, 0);
-  dlwInit(&pCollector->dlw, iType, &pCollector->b);
-  plwInit(&pCollector->plw, &pCollector->dlw, iDocid);
-  return pCollector;
-}
-static void dlcDelete(DLCollector *pCollector){
-  plwDestroy(&pCollector->plw);
-  dlwDestroy(&pCollector->dlw);
-  dataBufferDestroy(&pCollector->b);
-  SCRAMBLE(pCollector);
-  sqlite3_free(pCollector);
-}
-
-
-/* Copy the doclist data of iType in pData/nData into *out, trimming
-** unnecessary data as we go.  Only columns matching iColumn are
-** copied, all columns copied if iColumn is -1.  Elements with no
-** matching columns are dropped.  The output is an iOutType doclist.
-*/
-/* NOTE(shess) This code is only valid after all doclists are merged.
-** If this is run before merges, then doclist items which represent
-** deletion will be trimmed, and will thus not effect a deletion
-** during the merge.
-*/
-static void docListTrim(DocListType iType, const char *pData, int nData,
-                        int iColumn, DocListType iOutType, DataBuffer *out){
-  DLReader dlReader;
-  DLWriter dlWriter;
-
-  assert( iOutType<=iType );
-
-  dlrInit(&dlReader, iType, pData, nData);
-  dlwInit(&dlWriter, iOutType, out);
-
-  while( !dlrAtEnd(&dlReader) ){
-    PLReader plReader;
-    PLWriter plWriter;
-    int match = 0;
-
-    plrInit(&plReader, &dlReader);
-
-    while( !plrAtEnd(&plReader) ){
-      if( iColumn==-1 || plrColumn(&plReader)==iColumn ){
-        if( !match ){
-          plwInit(&plWriter, &dlWriter, dlrDocid(&dlReader));
-          match = 1;
-        }
-        plwAdd(&plWriter, plrColumn(&plReader), plrPosition(&plReader),
-               plrStartOffset(&plReader), plrEndOffset(&plReader));
-      }
-      plrStep(&plReader);
-    }
-    if( match ){
-      plwTerminate(&plWriter);
-      plwDestroy(&plWriter);
-    }
-
-    plrDestroy(&plReader);
-    dlrStep(&dlReader);
-  }
-  dlwDestroy(&dlWriter);
-  dlrDestroy(&dlReader);
-}
-
-/* Used by docListMerge() to keep doclists in the ascending order by
-** docid, then ascending order by age (so the newest comes first).
-*/
-typedef struct OrderedDLReader {
-  DLReader *pReader;
-
-  /* TODO(shess) If we assume that docListMerge pReaders is ordered by
-  ** age (which we do), then we could use pReader comparisons to break
-  ** ties.
-  */
-  int idx;
-} OrderedDLReader;
-
-/* Order eof to end, then by docid asc, idx desc. */
-static int orderedDLReaderCmp(OrderedDLReader *r1, OrderedDLReader *r2){
-  if( dlrAtEnd(r1->pReader) ){
-    if( dlrAtEnd(r2->pReader) ) return 0;  /* Both atEnd(). */
-    return 1;                              /* Only r1 atEnd(). */
-  }
-  if( dlrAtEnd(r2->pReader) ) return -1;   /* Only r2 atEnd(). */
-
-  if( dlrDocid(r1->pReader)<dlrDocid(r2->pReader) ) return -1;
-  if( dlrDocid(r1->pReader)>dlrDocid(r2->pReader) ) return 1;
-
-  /* Descending on idx. */
-  return r2->idx-r1->idx;
-}
-
-/* Bubble p[0] to appropriate place in p[1..n-1].  Assumes that
-** p[1..n-1] is already sorted.
-*/
-/* TODO(shess) Is this frequent enough to warrant a binary search?
-** Before implementing that, instrument the code to check.  In most
-** current usage, I expect that p[0] will be less than p[1] a very
-** high proportion of the time.
-*/
-static void orderedDLReaderReorder(OrderedDLReader *p, int n){
-  while( n>1 && orderedDLReaderCmp(p, p+1)>0 ){
-    OrderedDLReader tmp = p[0];
-    p[0] = p[1];
-    p[1] = tmp;
-    n--;
-    p++;
-  }
-}
-
-/* Given an array of doclist readers, merge their doclist elements
-** into out in sorted order (by docid), dropping elements from older
-** readers when there is a duplicate docid.  pReaders is assumed to be
-** ordered by age, oldest first.
-*/
-/* TODO(shess) nReaders must be <= MERGE_COUNT.  This should probably
-** be fixed.
-*/
-static void docListMerge(DataBuffer *out,
-                         DLReader *pReaders, int nReaders){
-  OrderedDLReader readers[MERGE_COUNT];
-  DLWriter writer;
-  int i, n;
-  const char *pStart = 0;
-  int nStart = 0;
-  sqlite_int64 iFirstDocid = 0, iLastDocid = 0;
-
-  assert( nReaders>0 );
-  if( nReaders==1 ){
-    dataBufferAppend(out, dlrDocData(pReaders), dlrAllDataBytes(pReaders));
-    return;
-  }
-
-  assert( nReaders<=MERGE_COUNT );
-  n = 0;
-  for(i=0; i<nReaders; i++){
-    assert( pReaders[i].iType==pReaders[0].iType );
-    readers[i].pReader = pReaders+i;
-    readers[i].idx = i;
-    n += dlrAllDataBytes(&pReaders[i]);
-  }
-  /* Conservatively size output to sum of inputs.  Output should end
-  ** up strictly smaller than input.
-  */
-  dataBufferExpand(out, n);
-
-  /* Get the readers into sorted order. */
-  while( i-->0 ){
-    orderedDLReaderReorder(readers+i, nReaders-i);
-  }
-
-  dlwInit(&writer, pReaders[0].iType, out);
-  while( !dlrAtEnd(readers[0].pReader) ){
-    sqlite_int64 iDocid = dlrDocid(readers[0].pReader);
-
-    /* If this is a continuation of the current buffer to copy, extend
-    ** that buffer.  memcpy() seems to be more efficient if it has a
-    ** lots of data to copy.
-    */
-    if( dlrDocData(readers[0].pReader)==pStart+nStart ){
-      nStart += dlrDocDataBytes(readers[0].pReader);
-    }else{
-      if( pStart!=0 ){
-        dlwAppend(&writer, pStart, nStart, iFirstDocid, iLastDocid);
-      }
-      pStart = dlrDocData(readers[0].pReader);
-      nStart = dlrDocDataBytes(readers[0].pReader);
-      iFirstDocid = iDocid;
-    }
-    iLastDocid = iDocid;
-    dlrStep(readers[0].pReader);
-
-    /* Drop all of the older elements with the same docid. */
-    for(i=1; i<nReaders &&
-             !dlrAtEnd(readers[i].pReader) &&
-             dlrDocid(readers[i].pReader)==iDocid; i++){
-      dlrStep(readers[i].pReader);
-    }
-
-    /* Get the readers back into order. */
-    while( i-->0 ){
-      orderedDLReaderReorder(readers+i, nReaders-i);
-    }
-  }
-
-  /* Copy over any remaining elements. */
-  if( nStart>0 ) dlwAppend(&writer, pStart, nStart, iFirstDocid, iLastDocid);
-  dlwDestroy(&writer);
-}
-
-/* Helper function for posListUnion().  Compares the current position
-** between left and right, returning as standard C idiom of <0 if
-** left<right, >0 if left>right, and 0 if left==right.  "End" always
-** compares greater.
-*/
-static int posListCmp(PLReader *pLeft, PLReader *pRight){
-  assert( pLeft->iType==pRight->iType );
-  if( pLeft->iType==DL_DOCIDS ) return 0;
-
-  if( plrAtEnd(pLeft) ) return plrAtEnd(pRight) ? 0 : 1;
-  if( plrAtEnd(pRight) ) return -1;
-
-  if( plrColumn(pLeft)<plrColumn(pRight) ) return -1;
-  if( plrColumn(pLeft)>plrColumn(pRight) ) return 1;
-
-  if( plrPosition(pLeft)<plrPosition(pRight) ) return -1;
-  if( plrPosition(pLeft)>plrPosition(pRight) ) return 1;
-  if( pLeft->iType==DL_POSITIONS ) return 0;
-
-  if( plrStartOffset(pLeft)<plrStartOffset(pRight) ) return -1;
-  if( plrStartOffset(pLeft)>plrStartOffset(pRight) ) return 1;
-
-  if( plrEndOffset(pLeft)<plrEndOffset(pRight) ) return -1;
-  if( plrEndOffset(pLeft)>plrEndOffset(pRight) ) return 1;
-
-  return 0;
-}
-
-/* Write the union of position lists in pLeft and pRight to pOut.
-** "Union" in this case meaning "All unique position tuples".  Should
-** work with any doclist type, though both inputs and the output
-** should be the same type.
-*/
-static void posListUnion(DLReader *pLeft, DLReader *pRight, DLWriter *pOut){
-  PLReader left, right;
-  PLWriter writer;
-
-  assert( dlrDocid(pLeft)==dlrDocid(pRight) );
-  assert( pLeft->iType==pRight->iType );
-  assert( pLeft->iType==pOut->iType );
-
-  plrInit(&left, pLeft);
-  plrInit(&right, pRight);
-  plwInit(&writer, pOut, dlrDocid(pLeft));
-
-  while( !plrAtEnd(&left) || !plrAtEnd(&right) ){
-    int c = posListCmp(&left, &right);
-    if( c<0 ){
-      plwCopy(&writer, &left);
-      plrStep(&left);
-    }else if( c>0 ){
-      plwCopy(&writer, &right);
-      plrStep(&right);
-    }else{
-      plwCopy(&writer, &left);
-      plrStep(&left);
-      plrStep(&right);
-    }
-  }
-
-  plwTerminate(&writer);
-  plwDestroy(&writer);
-  plrDestroy(&left);
-  plrDestroy(&right);
-}
-
-/* Write the union of doclists in pLeft and pRight to pOut.  For
-** docids in common between the inputs, the union of the position
-** lists is written.  Inputs and outputs are always type DL_DEFAULT.
-*/
-static void docListUnion(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 ){
-    if( nRight!=0) dataBufferAppend(pOut, pRight, nRight);
-    return;
-  }
-  if( nRight==0 ){
-    dataBufferAppend(pOut, pLeft, nLeft);
-    return;
-  }
-
-  dlrInit(&left, DL_DEFAULT, pLeft, nLeft);
-  dlrInit(&right, DL_DEFAULT, pRight, nRight);
-  dlwInit(&writer, DL_DEFAULT, pOut);
-
-  while( !dlrAtEnd(&left) || !dlrAtEnd(&right) ){
-    if( dlrAtEnd(&right) ){
-      dlwCopy(&writer, &left);
-      dlrStep(&left);
-    }else if( dlrAtEnd(&left) ){
-      dlwCopy(&writer, &right);
-      dlrStep(&right);
-    }else if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlwCopy(&writer, &left);
-      dlrStep(&left);
-    }else if( dlrDocid(&left)>dlrDocid(&right) ){
-      dlwCopy(&writer, &right);
-      dlrStep(&right);
-    }else{
-      posListUnion(&left, &right, &writer);
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/* 
-** This function is used as part of the implementation of phrase and
-** NEAR matching.
-**
-** pLeft and pRight are DLReaders positioned to the same docid in
-** lists of type DL_POSITION. This function writes an entry to the
-** DLWriter pOut for each position in pRight that is less than
-** (nNear+1) greater (but not equal to or smaller) than a position 
-** in pLeft. For example, if nNear is 0, and the positions contained
-** by pLeft and pRight are:
-**
-**    pLeft:  5 10 15 20
-**    pRight: 6  9 17 21
-**
-** then the docid is added to pOut. If pOut is of type DL_POSITIONS,
-** then a positionids "6" and "21" are also added to pOut.
-**
-** If boolean argument isSaveLeft is true, then positionids are copied
-** from pLeft instead of pRight. In the example above, the positions "5"
-** and "20" would be added instead of "6" and "21".
-*/
-static void posListPhraseMerge(
-  DLReader *pLeft, 
-  DLReader *pRight,
-  int nNear,
-  int isSaveLeft,
-  DLWriter *pOut
-){
-  PLReader left, right;
-  PLWriter writer;
-  int match = 0;
-
-  assert( dlrDocid(pLeft)==dlrDocid(pRight) );
-  assert( pOut->iType!=DL_POSITIONS_OFFSETS );
-
-  plrInit(&left, pLeft);
-  plrInit(&right, pRight);
-
-  while( !plrAtEnd(&left) && !plrAtEnd(&right) ){
-    if( plrColumn(&left)<plrColumn(&right) ){
-      plrStep(&left);
-    }else if( plrColumn(&left)>plrColumn(&right) ){
-      plrStep(&right);
-    }else if( plrPosition(&left)>=plrPosition(&right) ){
-      plrStep(&right);
-    }else{
-      if( (plrPosition(&right)-plrPosition(&left))<=(nNear+1) ){
-        if( !match ){
-          plwInit(&writer, pOut, dlrDocid(pLeft));
-          match = 1;
-        }
-        if( !isSaveLeft ){
-          plwAdd(&writer, plrColumn(&right), plrPosition(&right), 0, 0);
-        }else{
-          plwAdd(&writer, plrColumn(&left), plrPosition(&left), 0, 0);
-        }
-        plrStep(&right);
-      }else{
-        plrStep(&left);
-      }
-    }
-  }
-
-  if( match ){
-    plwTerminate(&writer);
-    plwDestroy(&writer);
-  }
-
-  plrDestroy(&left);
-  plrDestroy(&right);
-}
-
 /*
-** Compare the values pointed to by the PLReaders passed as arguments. 
-** Return -1 if the value pointed to by pLeft is considered less than
-** the value pointed to by pRight, +1 if it is considered greater
-** than it, or 0 if it is equal. i.e.
-**
-**     (*pLeft - *pRight)
-**
-** A PLReader that is in the EOF condition is considered greater than
-** any other. If neither argument is in EOF state, the return value of
-** plrColumn() is used. If the plrColumn() values are equal, the
-** comparison is on the basis of plrPosition().
+** Return the number of bytes required to encode v as a varint
 */
-static int plrCompare(PLReader *pLeft, PLReader *pRight){
-  assert(!plrAtEnd(pLeft) || !plrAtEnd(pRight));
-
-  if( plrAtEnd(pRight) || plrAtEnd(pLeft) ){
-    return (plrAtEnd(pRight) ? -1 : 1);
-  }
-  if( plrColumn(pLeft)!=plrColumn(pRight) ){
-    return ((plrColumn(pLeft)<plrColumn(pRight)) ? -1 : 1);
-  }
-  if( plrPosition(pLeft)!=plrPosition(pRight) ){
-    return ((plrPosition(pLeft)<plrPosition(pRight)) ? -1 : 1);
-  }
-  return 0;
-}
-
-/* We have two doclists with positions:  pLeft and pRight. Depending
-** on the value of the nNear parameter, perform either a phrase
-** intersection (if nNear==0) or a NEAR intersection (if nNear>0)
-** and write the results into pOut.
-**
-** A phrase intersection means that two documents only match
-** if pLeft.iPos+1==pRight.iPos.
-**
-** A NEAR intersection means that two documents only match if 
-** (abs(pLeft.iPos-pRight.iPos)<nNear).
-**
-** If a NEAR intersection is requested, then the nPhrase argument should
-** be passed the number of tokens in the two operands to the NEAR operator
-** combined. For example:
-**
-**       Query syntax               nPhrase
-**      ------------------------------------
-**       "A B C" NEAR "D E"         5
-**       A NEAR B                   2
-**
-** iType controls the type of data written to pOut.  If iType is
-** DL_POSITIONS, the positions are those from pRight.
-*/
-static void docListPhraseMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  int nNear,            /* 0 for a phrase merge, non-zero for a NEAR merge */
-  int nPhrase,          /* Number of tokens in left+right operands to NEAR */
-  DocListType iType,    /* Type of doclist to write to pOut */
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 || nRight==0 ) return;
-
-  assert( iType!=DL_POSITIONS_OFFSETS );
-
-  dlrInit(&left, DL_POSITIONS, pLeft, nLeft);
-  dlrInit(&right, DL_POSITIONS, pRight, nRight);
-  dlwInit(&writer, iType, pOut);
-
-  while( !dlrAtEnd(&left) && !dlrAtEnd(&right) ){
-    if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlrStep(&left);
-    }else if( dlrDocid(&right)<dlrDocid(&left) ){
-      dlrStep(&right);
-    }else{
-      if( nNear==0 ){
-        posListPhraseMerge(&left, &right, 0, 0, &writer);
-      }else{
-        /* This case occurs when two terms (simple terms or phrases) are
-         * connected by a NEAR operator, span (nNear+1). i.e.
-         *
-         *     '"terrible company" NEAR widget'
-         */
-        DataBuffer one = {0, 0, 0};
-        DataBuffer two = {0, 0, 0};
-
-        DLWriter dlwriter2;
-        DLReader dr1 = {0, 0, 0, 0, 0}; 
-        DLReader dr2 = {0, 0, 0, 0, 0};
-
-        dlwInit(&dlwriter2, iType, &one);
-        posListPhraseMerge(&right, &left, nNear-3+nPhrase, 1, &dlwriter2);
-        dlwInit(&dlwriter2, iType, &two);
-        posListPhraseMerge(&left, &right, nNear-1, 0, &dlwriter2);
-
-        if( one.nData) dlrInit(&dr1, iType, one.pData, one.nData);
-        if( two.nData) dlrInit(&dr2, iType, two.pData, two.nData);
-
-        if( !dlrAtEnd(&dr1) || !dlrAtEnd(&dr2) ){
-          PLReader pr1 = {0};
-          PLReader pr2 = {0};
-
-          PLWriter plwriter;
-          plwInit(&plwriter, &writer, dlrDocid(dlrAtEnd(&dr1)?&dr2:&dr1));
-
-          if( one.nData ) plrInit(&pr1, &dr1);
-          if( two.nData ) plrInit(&pr2, &dr2);
-          while( !plrAtEnd(&pr1) || !plrAtEnd(&pr2) ){
-            int iCompare = plrCompare(&pr1, &pr2);
-            switch( iCompare ){
-              case -1:
-                plwCopy(&plwriter, &pr1);
-                plrStep(&pr1);
-                break;
-              case 1:
-                plwCopy(&plwriter, &pr2);
-                plrStep(&pr2);
-                break;
-              case 0:
-                plwCopy(&plwriter, &pr1);
-                plrStep(&pr1);
-                plrStep(&pr2);
-                break;
-            }
-          }
-          plwTerminate(&plwriter);
-        }
-        dataBufferDestroy(&one);
-        dataBufferDestroy(&two);
-      }
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/* We have two DL_DOCIDS doclists:  pLeft and pRight.
-** Write the intersection of these two doclists into pOut as a
-** DL_DOCIDS doclist.
-*/
-static void docListAndMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 || nRight==0 ) return;
-
-  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
-  dlrInit(&right, DL_DOCIDS, pRight, nRight);
-  dlwInit(&writer, DL_DOCIDS, pOut);
-
-  while( !dlrAtEnd(&left) && !dlrAtEnd(&right) ){
-    if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlrStep(&left);
-    }else if( dlrDocid(&right)<dlrDocid(&left) ){
-      dlrStep(&right);
-    }else{
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/* We have two DL_DOCIDS doclists:  pLeft and pRight.
-** Write the union of these two doclists into pOut as a
-** DL_DOCIDS doclist.
-*/
-static void docListOrMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 ){
-    if( nRight!=0 ) dataBufferAppend(pOut, pRight, nRight);
-    return;
-  }
-  if( nRight==0 ){
-    dataBufferAppend(pOut, pLeft, nLeft);
-    return;
-  }
-
-  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
-  dlrInit(&right, DL_DOCIDS, pRight, nRight);
-  dlwInit(&writer, DL_DOCIDS, pOut);
-
-  while( !dlrAtEnd(&left) || !dlrAtEnd(&right) ){
-    if( dlrAtEnd(&right) ){
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-    }else if( dlrAtEnd(&left) ){
-      dlwAdd(&writer, dlrDocid(&right));
-      dlrStep(&right);
-    }else if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-    }else if( dlrDocid(&right)<dlrDocid(&left) ){
-      dlwAdd(&writer, dlrDocid(&right));
-      dlrStep(&right);
-    }else{
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/* We have two DL_DOCIDS doclists:  pLeft and pRight.
-** Write into pOut as DL_DOCIDS doclist containing all documents that
-** occur in pLeft but not in pRight.
-*/
-static void docListExceptMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 ) return;
-  if( nRight==0 ){
-    dataBufferAppend(pOut, pLeft, nLeft);
-    return;
-  }
-
-  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
-  dlrInit(&right, DL_DOCIDS, pRight, nRight);
-  dlwInit(&writer, DL_DOCIDS, pOut);
-
-  while( !dlrAtEnd(&left) ){
-    while( !dlrAtEnd(&right) && dlrDocid(&right)<dlrDocid(&left) ){
-      dlrStep(&right);
-    }
-    if( dlrAtEnd(&right) || dlrDocid(&left)<dlrDocid(&right) ){
-      dlwAdd(&writer, dlrDocid(&left));
-    }
-    dlrStep(&left);
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-static char *string_dup_n(const char *s, int n){
-  char *str = sqlite3_malloc(n + 1);
-  memcpy(str, s, n);
-  str[n] = '\0';
-  return str;
-}
-
-/* Duplicate a string; the caller must free() the returned string.
- * (We don't use strdup() since it is not part of the standard C library and
- * may not be available everywhere.) */
-static char *string_dup(const char *s){
-  return string_dup_n(s, strlen(s));
-}
-
-/* Format a string, replacing each occurrence of the % character with
- * zDb.zName.  This may be more convenient than sqlite_mprintf()
- * when one string is used repeatedly in a format string.
- * The caller must free() the returned string. */
-static char *string_format(const char *zFormat,
-                           const char *zDb, const char *zName){
-  const char *p;
-  size_t len = 0;
-  size_t nDb = strlen(zDb);
-  size_t nName = strlen(zName);
-  size_t nFullTableName = nDb+1+nName;
-  char *result;
-  char *r;
-
-  /* first compute length needed */
-  for(p = zFormat ; *p ; ++p){
-    len += (*p=='%' ? nFullTableName : 1);
-  }
-  len += 1;  /* for null terminator */
-
-  r = result = sqlite3_malloc(len);
-  for(p = zFormat; *p; ++p){
-    if( *p=='%' ){
-      memcpy(r, zDb, nDb);
-      r += nDb;
-      *r++ = '.';
-      memcpy(r, zName, nName);
-      r += nName;
-    } else {
-      *r++ = *p;
-    }
-  }
-  *r++ = '\0';
-  assert( r == result + len );
-  return result;
-}
-
-static int sql_exec(sqlite3 *db, const char *zDb, const char *zName,
-                    const char *zFormat){
-  char *zCommand = string_format(zFormat, zDb, zName);
-  int rc;
-  FTSTRACE(("FTS3 sql: %s\n", zCommand));
-  rc = sqlite3_exec(db, zCommand, NULL, 0, NULL);
-  sqlite3_free(zCommand);
-  return rc;
-}
-
-static int sql_prepare(sqlite3 *db, const char *zDb, const char *zName,
-                       sqlite3_stmt **ppStmt, const char *zFormat){
-  char *zCommand = string_format(zFormat, zDb, zName);
-  int rc;
-  FTSTRACE(("FTS3 prepare: %s\n", zCommand));
-  rc = sqlite3_prepare_v2(db, zCommand, -1, ppStmt, NULL);
-  sqlite3_free(zCommand);
-  return rc;
-}
-
-/* end utility functions */
-
-/* Forward reference */
-typedef struct fulltext_vtab fulltext_vtab;
-
-/*
-** An instance of the following structure keeps track of generated
-** matching-word offset information and snippets.
-*/
-typedef struct Snippet {
-  int nMatch;     /* Total number of matches */
-  int nAlloc;     /* Space allocated for aMatch[] */
-  struct snippetMatch { /* One entry for each matching term */
-    char snStatus;       /* Status flag for use while constructing snippets */
-    short int iCol;      /* The column that contains the match */
-    short int iTerm;     /* The index in Query.pTerms[] of the matching term */
-    int iToken;          /* The index of the matching document token */
-    short int nByte;     /* Number of bytes in the term */
-    int iStart;          /* The offset to the first character of the term */
-  } *aMatch;      /* Points to space obtained from malloc */
-  char *zOffset;  /* Text rendering of aMatch[] */
-  int nOffset;    /* strlen(zOffset) */
-  char *zSnippet; /* Snippet text */
-  int nSnippet;   /* strlen(zSnippet) */
-} Snippet;
-
-
-typedef enum QueryType {
-  QUERY_GENERIC,   /* table scan */
-  QUERY_DOCID,     /* lookup by docid */
-  QUERY_FULLTEXT   /* QUERY_FULLTEXT + [i] is a full-text search for column i*/
-} QueryType;
-
-typedef enum fulltext_statement {
-  CONTENT_INSERT_STMT,
-  CONTENT_SELECT_STMT,
-  CONTENT_UPDATE_STMT,
-  CONTENT_DELETE_STMT,
-  CONTENT_EXISTS_STMT,
-
-  BLOCK_INSERT_STMT,
-  BLOCK_SELECT_STMT,
-  BLOCK_DELETE_STMT,
-  BLOCK_DELETE_ALL_STMT,
-
-  SEGDIR_MAX_INDEX_STMT,
-  SEGDIR_SET_STMT,
-  SEGDIR_SELECT_LEVEL_STMT,
-  SEGDIR_SPAN_STMT,
-  SEGDIR_DELETE_STMT,
-  SEGDIR_SELECT_SEGMENT_STMT,
-  SEGDIR_SELECT_ALL_STMT,
-  SEGDIR_DELETE_ALL_STMT,
-  SEGDIR_COUNT_STMT,
-
-  MAX_STMT                     /* Always at end! */
-} fulltext_statement;
-
-/* These must exactly match the enum above. */
-/* TODO(shess): Is there some risk that a statement will be used in two
-** cursors at once, e.g.  if a query joins a virtual table to itself?
-** If so perhaps we should move some of these to the cursor object.
-*/
-static const char *const fulltext_zStatement[MAX_STMT] = {
-  /* CONTENT_INSERT */ NULL,  /* generated in contentInsertStatement() */
-  /* CONTENT_SELECT */ NULL,  /* generated in contentSelectStatement() */
-  /* CONTENT_UPDATE */ NULL,  /* generated in contentUpdateStatement() */
-  /* CONTENT_DELETE */ "delete from %_content where docid = ?",
-  /* CONTENT_EXISTS */ "select docid from %_content limit 1",
-
-  /* BLOCK_INSERT */
-  "insert into %_segments (blockid, block) values (null, ?)",
-  /* BLOCK_SELECT */ "select block from %_segments where blockid = ?",
-  /* BLOCK_DELETE */ "delete from %_segments where blockid between ? and ?",
-  /* BLOCK_DELETE_ALL */ "delete from %_segments",
-
-  /* SEGDIR_MAX_INDEX */ "select max(idx) from %_segdir where level = ?",
-  /* SEGDIR_SET */ "insert into %_segdir values (?, ?, ?, ?, ?, ?)",
-  /* SEGDIR_SELECT_LEVEL */
-  "select start_block, leaves_end_block, root from %_segdir "
-  " where level = ? order by idx",
-  /* SEGDIR_SPAN */
-  "select min(start_block), max(end_block) from %_segdir "
-  " where level = ? and start_block <> 0",
-  /* SEGDIR_DELETE */ "delete from %_segdir where level = ?",
-
-  /* NOTE(shess): The first three results of the following two
-  ** statements must match.
-  */
-  /* SEGDIR_SELECT_SEGMENT */
-  "select start_block, leaves_end_block, root from %_segdir "
-  " where level = ? and idx = ?",
-  /* SEGDIR_SELECT_ALL */
-  "select start_block, leaves_end_block, root from %_segdir "
-  " order by level desc, idx asc",
-  /* SEGDIR_DELETE_ALL */ "delete from %_segdir",
-  /* SEGDIR_COUNT */ "select count(*), ifnull(max(level),0) from %_segdir",
-};
-
-/*
-** A connection to a fulltext index is an instance of the following
-** structure.  The xCreate and xConnect methods create an instance
-** of this structure and xDestroy and xDisconnect free that instance.
-** All other methods receive a pointer to the structure as one of their
-** arguments.
-*/
-struct fulltext_vtab {
-  sqlite3_vtab base;               /* Base class used by SQLite core */
-  sqlite3 *db;                     /* The database connection */
-  const char *zDb;                 /* logical database name */
-  const char *zName;               /* virtual table name */
-  int nColumn;                     /* number of columns in virtual table */
-  char **azColumn;                 /* column names.  malloced */
-  char **azContentColumn;          /* column names in content table; malloced */
-  sqlite3_tokenizer *pTokenizer;   /* tokenizer for inserts and queries */
-
-  /* Precompiled statements which we keep as long as the table is
-  ** open.
-  */
-  sqlite3_stmt *pFulltextStatements[MAX_STMT];
-
-  /* Precompiled statements used for segment merges.  We run a
-  ** separate select across the leaf level of each tree being merged.
-  */
-  sqlite3_stmt *pLeafSelectStmts[MERGE_COUNT];
-  /* The statement used to prepare pLeafSelectStmts. */
-#define LEAF_SELECT \
-  "select block from %_segments where blockid between ? and ? order by blockid"
-
-  /* These buffer pending index updates during transactions.
-  ** nPendingData estimates the memory size of the pending data.  It
-  ** doesn't include the hash-bucket overhead, nor any malloc
-  ** overhead.  When nPendingData exceeds kPendingThreshold, the
-  ** buffer is flushed even before the transaction closes.
-  ** pendingTerms stores the data, and is only valid when nPendingData
-  ** is >=0 (nPendingData<0 means pendingTerms has not been
-  ** initialized).  iPrevDocid is the last docid written, used to make
-  ** certain we're inserting in sorted order.
-  */
-  int nPendingData;
-#define kPendingThreshold (1*1024*1024)
-  sqlite_int64 iPrevDocid;
-  fts3Hash pendingTerms;
-};
-
-/*
-** When the core wants to do a query, it create a cursor using a
-** call to xOpen.  This structure is an instance of a cursor.  It
-** is destroyed by xClose.
-*/
-typedef struct fulltext_cursor {
-  sqlite3_vtab_cursor base;        /* Base class used by SQLite core */
-  QueryType iCursorType;           /* Copy of sqlite3_index_info.idxNum */
-  sqlite3_stmt *pStmt;             /* Prepared statement in use by the cursor */
-  int eof;                         /* True if at End Of Results */
-  Fts3Expr *pExpr;                 /* Parsed MATCH query string */
-  Snippet snippet;                 /* Cached snippet for the current row */
-  int iColumn;                     /* Column being searched */
-  DataBuffer result;               /* Doclist results from fulltextQuery */
-  DLReader reader;                 /* Result reader if result not empty */
-} fulltext_cursor;
-
-static fulltext_vtab *cursor_vtab(fulltext_cursor *c){
-  return (fulltext_vtab *) c->base.pVtab;
-}
-
-static const sqlite3_module fts3Module;   /* forward declaration */
-
-/* Return a dynamically generated statement of the form
- *   insert into %_content (docid, ...) values (?, ...)
- */
-static const char *contentInsertStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  int i;
-
-  initStringBuffer(&sb);
-  append(&sb, "insert into %_content (docid, ");
-  appendList(&sb, v->nColumn, v->azContentColumn);
-  append(&sb, ") values (?");
-  for(i=0; i<v->nColumn; ++i)
-    append(&sb, ", ?");
-  append(&sb, ")");
-  return stringBufferData(&sb);
-}
-
-/* Return a dynamically generated statement of the form
- *   select <content columns> from %_content where docid = ?
- */
-static const char *contentSelectStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  initStringBuffer(&sb);
-  append(&sb, "SELECT ");
-  appendList(&sb, v->nColumn, v->azContentColumn);
-  append(&sb, " FROM %_content WHERE docid = ?");
-  return stringBufferData(&sb);
-}
-
-/* Return a dynamically generated statement of the form
- *   update %_content set [col_0] = ?, [col_1] = ?, ...
- *                    where docid = ?
- */
-static const char *contentUpdateStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  int i;
-
-  initStringBuffer(&sb);
-  append(&sb, "update %_content set ");
-  for(i=0; i<v->nColumn; ++i) {
-    if( i>0 ){
-      append(&sb, ", ");
-    }
-    append(&sb, v->azContentColumn[i]);
-    append(&sb, " = ?");
-  }
-  append(&sb, " where docid = ?");
-  return stringBufferData(&sb);
-}
-
-/* Puts a freshly-prepared statement determined by iStmt in *ppStmt.
-** If the indicated statement has never been prepared, it is prepared
-** and cached, otherwise the cached version is reset.
-*/
-static int sql_get_statement(fulltext_vtab *v, fulltext_statement iStmt,
-                             sqlite3_stmt **ppStmt){
-  assert( iStmt<MAX_STMT );
-  if( v->pFulltextStatements[iStmt]==NULL ){
-    const char *zStmt;
-    int rc;
-    switch( iStmt ){
-      case CONTENT_INSERT_STMT:
-        zStmt = contentInsertStatement(v); break;
-      case CONTENT_SELECT_STMT:
-        zStmt = contentSelectStatement(v); break;
-      case CONTENT_UPDATE_STMT:
-        zStmt = contentUpdateStatement(v); break;
-      default:
-        zStmt = fulltext_zStatement[iStmt];
-    }
-    rc = sql_prepare(v->db, v->zDb, v->zName, &v->pFulltextStatements[iStmt],
-                         zStmt);
-    if( zStmt != fulltext_zStatement[iStmt]) sqlite3_free((void *) zStmt);
-    if( rc!=SQLITE_OK ) return rc;
-  } else {
-    int rc = sqlite3_reset(v->pFulltextStatements[iStmt]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  *ppStmt = v->pFulltextStatements[iStmt];
-  return SQLITE_OK;
-}
-
-/* Like sqlite3_step(), but convert SQLITE_DONE to SQLITE_OK and
-** SQLITE_ROW to SQLITE_ERROR.  Useful for statements like UPDATE,
-** where we expect no results.
-*/
-static int sql_single_step(sqlite3_stmt *s){
-  int rc = sqlite3_step(s);
-  return (rc==SQLITE_DONE) ? SQLITE_OK : rc;
-}
-
-/* Like sql_get_statement(), but for special replicated LEAF_SELECT
-** statements.  idx -1 is a special case for an uncached version of
-** the statement (used in the optimize implementation).
-*/
-/* TODO(shess) Write version for generic statements and then share
-** that between the cached-statement functions.
-*/
-static int sql_get_leaf_statement(fulltext_vtab *v, int idx,
-                                  sqlite3_stmt **ppStmt){
-  assert( idx>=-1 && idx<MERGE_COUNT );
-  if( idx==-1 ){
-    return sql_prepare(v->db, v->zDb, v->zName, ppStmt, LEAF_SELECT);
-  }else if( v->pLeafSelectStmts[idx]==NULL ){
-    int rc = sql_prepare(v->db, v->zDb, v->zName, &v->pLeafSelectStmts[idx],
-                         LEAF_SELECT);
-    if( rc!=SQLITE_OK ) return rc;
-  }else{
-    int rc = sqlite3_reset(v->pLeafSelectStmts[idx]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  *ppStmt = v->pLeafSelectStmts[idx];
-  return SQLITE_OK;
-}
-
-/* insert into %_content (docid, ...) values ([docid], [pValues])
-** If the docid contains SQL NULL, then a unique docid will be
-** generated.
-*/
-static int content_insert(fulltext_vtab *v, sqlite3_value *docid,
-                          sqlite3_value **pValues){
-  sqlite3_stmt *s;
-  int i;
-  int rc = sql_get_statement(v, CONTENT_INSERT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_value(s, 1, docid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i=0; i<v->nColumn; ++i){
-    rc = sqlite3_bind_value(s, 2+i, pValues[i]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  return sql_single_step(s);
-}
-
-/* update %_content set col0 = pValues[0], col1 = pValues[1], ...
- *                  where docid = [iDocid] */
-static int content_update(fulltext_vtab *v, sqlite3_value **pValues,
-                          sqlite_int64 iDocid){
-  sqlite3_stmt *s;
-  int i;
-  int rc = sql_get_statement(v, CONTENT_UPDATE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i=0; i<v->nColumn; ++i){
-    rc = sqlite3_bind_value(s, 1+i, pValues[i]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  rc = sqlite3_bind_int64(s, 1+v->nColumn, iDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-static void freeStringArray(int nString, const char **pString){
-  int i;
-
-  for (i=0 ; i < nString ; ++i) {
-    if( pString[i]!=NULL ) sqlite3_free((void *) pString[i]);
-  }
-  sqlite3_free((void *) pString);
-}
-
-/* select * from %_content where docid = [iDocid]
- * The caller must delete the returned array and all strings in it.
- * null fields will be NULL in the returned array.
- *
- * TODO: Perhaps we should return pointer/length strings here for consistency
- * with other code which uses pointer/length. */
-static int content_select(fulltext_vtab *v, sqlite_int64 iDocid,
-                          const char ***pValues){
-  sqlite3_stmt *s;
-  const char **values;
-  int i;
-  int rc;
-
-  *pValues = NULL;
-
-  rc = sql_get_statement(v, CONTENT_SELECT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc!=SQLITE_ROW ) return rc;
-
-  values = (const char **) sqlite3_malloc(v->nColumn * sizeof(const char *));
-  for(i=0; i<v->nColumn; ++i){
-    if( sqlite3_column_type(s, i)==SQLITE_NULL ){
-      values[i] = NULL;
-    }else{
-      values[i] = string_dup((char*)sqlite3_column_text(s, i));
-    }
-  }
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ){
-    *pValues = values;
-    return SQLITE_OK;
-  }
-
-  freeStringArray(v->nColumn, values);
-  return rc;
-}
-
-/* delete from %_content where docid = [iDocid ] */
-static int content_delete(fulltext_vtab *v, sqlite_int64 iDocid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, CONTENT_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Returns SQLITE_ROW if any rows exist in %_content, SQLITE_DONE if
-** no rows exist, and any error in case of failure.
-*/
-static int content_exists(fulltext_vtab *v){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, CONTENT_EXISTS_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc!=SQLITE_ROW ) return rc;
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_ROW;
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  return rc;
-}
-
-/* insert into %_segments values ([pData])
-**   returns assigned blockid in *piBlockid
-*/
-static int block_insert(fulltext_vtab *v, const char *pData, int nData,
-                        sqlite_int64 *piBlockid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, BLOCK_INSERT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_blob(s, 1, pData, nData, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-
-  /* blockid column is an alias for rowid. */
-  *piBlockid = sqlite3_last_insert_rowid(v->db);
-  return SQLITE_OK;
-}
-
-/* delete from %_segments
-**   where blockid between [iStartBlockid] and [iEndBlockid]
-**
-** Deletes the range of blocks, inclusive, used to delete the blocks
-** which form a segment.
-*/
-static int block_delete(fulltext_vtab *v,
-                        sqlite_int64 iStartBlockid, sqlite_int64 iEndBlockid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, BLOCK_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iStartBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 2, iEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Returns SQLITE_ROW with *pidx set to the maximum segment idx found
-** at iLevel.  Returns SQLITE_DONE if there are no segments at
-** iLevel.  Otherwise returns an error.
-*/
-static int segdir_max_index(fulltext_vtab *v, int iLevel, int *pidx){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_MAX_INDEX_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  /* Should always get at least one row due to how max() works. */
-  if( rc==SQLITE_DONE ) return SQLITE_DONE;
-  if( rc!=SQLITE_ROW ) return rc;
-
-  /* NULL means that there were no inputs to max(). */
-  if( SQLITE_NULL==sqlite3_column_type(s, 0) ){
-    rc = sqlite3_step(s);
-    if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-    return rc;
-  }
-
-  *pidx = sqlite3_column_int(s, 0);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-  return SQLITE_ROW;
-}
-
-/* insert into %_segdir values (
-**   [iLevel], [idx],
-**   [iStartBlockid], [iLeavesEndBlockid], [iEndBlockid],
-**   [pRootData]
-** )
-*/
-static int segdir_set(fulltext_vtab *v, int iLevel, int idx,
-                      sqlite_int64 iStartBlockid,
-                      sqlite_int64 iLeavesEndBlockid,
-                      sqlite_int64 iEndBlockid,
-                      const char *pRootData, int nRootData){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_SET_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 2, idx);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 3, iStartBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 4, iLeavesEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 5, iEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_blob(s, 6, pRootData, nRootData, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Queries %_segdir for the block span of the segments in level
-** iLevel.  Returns SQLITE_DONE if there are no blocks for iLevel,
-** SQLITE_ROW if there are blocks, else an error.
-*/
-static int segdir_span(fulltext_vtab *v, int iLevel,
-                       sqlite_int64 *piStartBlockid,
-                       sqlite_int64 *piEndBlockid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_SPAN_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_DONE;  /* Should never happen */
-  if( rc!=SQLITE_ROW ) return rc;
-
-  /* This happens if all segments at this level are entirely inline. */
-  if( SQLITE_NULL==sqlite3_column_type(s, 0) ){
-    /* We expect only one row.  We must execute another sqlite3_step()
-     * to complete the iteration; otherwise the table will remain locked. */
-    int rc2 = sqlite3_step(s);
-    if( rc2==SQLITE_ROW ) return SQLITE_ERROR;
-    return rc2;
-  }
-
-  *piStartBlockid = sqlite3_column_int64(s, 0);
-  *piEndBlockid = sqlite3_column_int64(s, 1);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-  return SQLITE_ROW;
-}
-
-/* Delete the segment blocks and segment directory records for all
-** segments at iLevel.
-*/
-static int segdir_delete(fulltext_vtab *v, int iLevel){
-  sqlite3_stmt *s;
-  sqlite_int64 iStartBlockid, iEndBlockid;
-  int rc = segdir_span(v, iLevel, &iStartBlockid, &iEndBlockid);
-  if( rc!=SQLITE_ROW && rc!=SQLITE_DONE ) return rc;
-
-  if( rc==SQLITE_ROW ){
-    rc = block_delete(v, iStartBlockid, iEndBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  /* Delete the segment directory itself. */
-  rc = sql_get_statement(v, SEGDIR_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Delete entire fts index, SQLITE_OK on success, relevant error on
-** failure.
-*/
-static int segdir_delete_all(fulltext_vtab *v){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_DELETE_ALL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sql_single_step(s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sql_get_statement(v, BLOCK_DELETE_ALL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Returns SQLITE_OK with *pnSegments set to the number of entries in
-** %_segdir and *piMaxLevel set to the highest level which has a
-** segment.  Otherwise returns the SQLite error which caused failure.
-*/
-static int segdir_count(fulltext_vtab *v, int *pnSegments, int *piMaxLevel){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_COUNT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  /* TODO(shess): This case should not be possible?  Should stronger
-  ** measures be taken if it happens?
-  */
-  if( rc==SQLITE_DONE ){
-    *pnSegments = 0;
-    *piMaxLevel = 0;
-    return SQLITE_OK;
-  }
-  if( rc!=SQLITE_ROW ) return rc;
-
-  *pnSegments = sqlite3_column_int(s, 0);
-  *piMaxLevel = sqlite3_column_int(s, 1);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_OK;
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  return rc;
-}
-
-/* TODO(shess) clearPendingTerms() is far down the file because
-** writeZeroSegment() is far down the file because LeafWriter is far
-** down the file.  Consider refactoring the code to move the non-vtab
-** code above the vtab code so that we don't need this forward
-** reference.
-*/
-static int clearPendingTerms(fulltext_vtab *v);
-
-/*
-** Free the memory used to contain a fulltext_vtab structure.
-*/
-static void fulltext_vtab_destroy(fulltext_vtab *v){
-  int iStmt, i;
-
-  FTSTRACE(("FTS3 Destroy %p\n", v));
-  for( iStmt=0; iStmt<MAX_STMT; iStmt++ ){
-    if( v->pFulltextStatements[iStmt]!=NULL ){
-      sqlite3_finalize(v->pFulltextStatements[iStmt]);
-      v->pFulltextStatements[iStmt] = NULL;
-    }
-  }
-
-  for( i=0; i<MERGE_COUNT; i++ ){
-    if( v->pLeafSelectStmts[i]!=NULL ){
-      sqlite3_finalize(v->pLeafSelectStmts[i]);
-      v->pLeafSelectStmts[i] = NULL;
-    }
-  }
-
-  if( v->pTokenizer!=NULL ){
-    v->pTokenizer->pModule->xDestroy(v->pTokenizer);
-    v->pTokenizer = NULL;
-  }
-
-  clearPendingTerms(v);
-
-  sqlite3_free(v->azColumn);
-  for(i = 0; i < v->nColumn; ++i) {
-    sqlite3_free(v->azContentColumn[i]);
-  }
-  sqlite3_free(v->azContentColumn);
-  sqlite3_free(v);
-}
-
-/*
-** Token types for parsing the arguments to xConnect or xCreate.
-*/
-#define TOKEN_EOF         0    /* End of file */
-#define TOKEN_SPACE       1    /* Any kind of whitespace */
-#define TOKEN_ID          2    /* An identifier */
-#define TOKEN_STRING      3    /* A string literal */
-#define TOKEN_PUNCT       4    /* A single punctuation character */
-
-/*
-** If X is a character that can be used in an identifier then
-** ftsIdChar(X) will be true.  Otherwise it is false.
-**
-** For ASCII, any character with the high-order bit set is
-** allowed in an identifier.  For 7-bit characters, 
-** isFtsIdChar[X] must be 1.
-**
-** Ticket #1066.  the SQL standard does not allow '$' in the
-** middle of identfiers.  But many SQL implementations do. 
-** SQLite will allow '$' in identifiers for compatibility.
-** But the feature is undocumented.
-*/
-static const char isFtsIdChar[] = {
-/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
-    0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
-};
-#define ftsIdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && isFtsIdChar[c-0x20]))
-
-
-/*
-** Return the length of the token that begins at z[0]. 
-** Store the token type in *tokenType before returning.
-*/
-static int ftsGetToken(const char *z, int *tokenType){
-  int i, c;
-  switch( *z ){
-    case 0: {
-      *tokenType = TOKEN_EOF;
-      return 0;
-    }
-    case ' ': case '\t': case '\n': case '\f': case '\r': {
-      for(i=1; safe_isspace(z[i]); i++){}
-      *tokenType = TOKEN_SPACE;
-      return i;
-    }
-    case '`':
-    case '\'':
-    case '"': {
-      int delim = z[0];
-      for(i=1; (c=z[i])!=0; i++){
-        if( c==delim ){
-          if( z[i+1]==delim ){
-            i++;
-          }else{
-            break;
-          }
-        }
-      }
-      *tokenType = TOKEN_STRING;
-      return i + (c!=0);
-    }
-    case '[': {
-      for(i=1, c=z[0]; c!=']' && (c=z[i])!=0; i++){}
-      *tokenType = TOKEN_ID;
-      return i;
-    }
-    default: {
-      if( !ftsIdChar(*z) ){
-        break;
-      }
-      for(i=1; ftsIdChar(z[i]); i++){}
-      *tokenType = TOKEN_ID;
-      return i;
-    }
-  }
-  *tokenType = TOKEN_PUNCT;
-  return 1;
-}
-
-/*
-** A token extracted from a string is an instance of the following
-** structure.
-*/
-typedef struct FtsToken {
-  const char *z;       /* Pointer to token text.  Not '\000' terminated */
-  short int n;         /* Length of the token text in bytes. */
-} FtsToken;
-
-/*
-** Given a input string (which is really one of the argv[] parameters
-** passed into xConnect or xCreate) split the string up into tokens.
-** Return an array of pointers to '\000' terminated strings, one string
-** for each non-whitespace token.
-**
-** The returned array is terminated by a single NULL pointer.
-**
-** Space to hold the returned array is obtained from a single
-** malloc and should be freed by passing the return value to free().
-** The individual strings within the token list are all a part of
-** the single memory allocation and will all be freed at once.
-*/
-static char **tokenizeString(const char *z, int *pnToken){
-  int nToken = 0;
-  FtsToken *aToken = sqlite3_malloc( strlen(z) * sizeof(aToken[0]) );
-  int n = 1;
-  int e, i;
-  int totalSize = 0;
-  char **azToken;
-  char *zCopy;
-  while( n>0 ){
-    n = ftsGetToken(z, &e);
-    if( e!=TOKEN_SPACE ){
-      aToken[nToken].z = z;
-      aToken[nToken].n = n;
-      nToken++;
-      totalSize += n+1;
-    }
-    z += n;
-  }
-  azToken = (char**)sqlite3_malloc( nToken*sizeof(char*) + totalSize );
-  zCopy = (char*)&azToken[nToken];
-  nToken--;
-  for(i=0; i<nToken; i++){
-    azToken[i] = zCopy;
-    n = aToken[i].n;
-    memcpy(zCopy, aToken[i].z, n);
-    zCopy[n] = 0;
-    zCopy += n+1;
-  }
-  azToken[nToken] = 0;
-  sqlite3_free(aToken);
-  *pnToken = nToken;
-  return azToken;
+SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64 v){
+  int i = 0;
+  do{
+    i++;
+    v >>= 7;
+  }while( v!=0 );
+  return i;
 }
 
 /*
@@ -92366,1266 +116326,2537 @@ static char **tokenizeString(const char *z, int *pnToken){
 **     'xyz'   becomes   xyz
 **     [pqr]   becomes   pqr
 **     `mno`   becomes   mno
+**
 */
-static void dequoteString(char *z){
-  int quote;
-  int i, j;
-  if( z==0 ) return;
+SQLITE_PRIVATE void sqlite3Fts3Dequote(char *z){
+  char quote;                     /* Quote character (if any ) */
+
   quote = z[0];
-  switch( quote ){
-    case '\'':  break;
-    case '"':   break;
-    case '`':   break;                /* For MySQL compatibility */
-    case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
-    default:    return;
-  }
-  for(i=1, j=0; z[i]; i++){
-    if( z[i]==quote ){
-      if( z[i+1]==quote ){
-        z[j++] = quote;
-        i++;
+  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
+    int iIn = 1;                  /* Index of next byte to read from input */
+    int iOut = 0;                 /* Index of next byte to write to output */
+
+    /* If the first byte was a '[', then the close-quote character is a ']' */
+    if( quote=='[' ) quote = ']';  
+
+    while( ALWAYS(z[iIn]) ){
+      if( z[iIn]==quote ){
+        if( z[iIn+1]!=quote ) break;
+        z[iOut++] = quote;
+        iIn += 2;
       }else{
-        z[j++] = 0;
-        break;
-      }
-    }else{
-      z[j++] = z[i];
-    }
-  }
-}
-
-/*
-** The input azIn is a NULL-terminated list of tokens.  Remove the first
-** token and all punctuation tokens.  Remove the quotes from
-** around string literal tokens.
-**
-** Example:
-**
-**     input:      tokenize chinese ( 'simplifed' , 'mixed' )
-**     output:     chinese simplifed mixed
-**
-** Another example:
-**
-**     input:      delimiters ( '[' , ']' , '...' )
-**     output:     [ ] ...
-*/
-static void tokenListToIdList(char **azIn){
-  int i, j;
-  if( azIn ){
-    for(i=0, j=-1; azIn[i]; i++){
-      if( safe_isalnum(azIn[i][0]) || azIn[i][1] ){
-        dequoteString(azIn[i]);
-        if( j>=0 ){
-          azIn[j] = azIn[i];
-        }
-        j++;
+        z[iOut++] = z[iIn++];
       }
     }
-    azIn[j] = 0;
+    z[iOut] = '\0';
   }
 }
 
-
 /*
-** Find the first alphanumeric token in the string zIn.  Null-terminate
-** this token.  Remove any quotation marks.  And return a pointer to
-** the result.
+** Read a single varint from the doclist at *pp and advance *pp to point
+** to the first byte past the end of the varint.  Add the value of the varint
+** to *pVal.
 */
-static char *firstToken(char *zIn, char **pzTail){
-  int n, ttype;
-  while(1){
-    n = ftsGetToken(zIn, &ttype);
-    if( ttype==TOKEN_SPACE ){
-      zIn += n;
-    }else if( ttype==TOKEN_EOF ){
-      *pzTail = zIn;
-      return 0;
-    }else{
-      zIn[n] = 0;
-      *pzTail = &zIn[1];
-      dequoteString(zIn);
-      return zIn;
-    }
-  }
-  /*NOTREACHED*/
+static void fts3GetDeltaVarint(char **pp, sqlite3_int64 *pVal){
+  sqlite3_int64 iVal;
+  *pp += sqlite3Fts3GetVarint(*pp, &iVal);
+  *pVal += iVal;
 }
 
-/* Return true if...
+/*
+** When this function is called, *pp points to the first byte following a
+** varint that is part of a doclist (or position-list, or any other list
+** of varints). This function moves *pp to point to the start of that varint,
+** and sets *pVal by the varint value.
 **
-**   *  s begins with the string t, ignoring case
-**   *  s is longer than t
-**   *  The first character of s beyond t is not a alphanumeric
-** 
-** Ignore leading space in *s.
-**
-** To put it another way, return true if the first token of
-** s[] is t[].
+** Argument pStart points to the first byte of the doclist that the
+** varint is part of.
 */
-static int startsWith(const char *s, const char *t){
-  while( safe_isspace(*s) ){ s++; }
-  while( *t ){
-    if( safe_tolower(*s++)!=safe_tolower(*t++) ) return 0;
-  }
-  return *s!='_' && !safe_isalnum(*s);
+static void fts3GetReverseVarint(
+  char **pp, 
+  char *pStart, 
+  sqlite3_int64 *pVal
+){
+  sqlite3_int64 iVal;
+  char *p;
+
+  /* Pointer p now points at the first byte past the varint we are 
+  ** interested in. So, unless the doclist is corrupt, the 0x80 bit is
+  ** clear on character p[-1]. */
+  for(p = (*pp)-2; p>=pStart && *p&0x80; p--);
+  p++;
+  *pp = p;
+
+  sqlite3Fts3GetVarint(p, &iVal);
+  *pVal = iVal;
 }
 
 /*
-** An instance of this structure defines the "spec" of a
-** full text index.  This structure is populated by parseSpec
-** and use by fulltextConnect and fulltextCreate.
+** The xDisconnect() virtual table method.
 */
-typedef struct TableSpec {
-  const char *zDb;         /* Logical database name */
-  const char *zName;       /* Name of the full-text index */
-  int nColumn;             /* Number of columns to be indexed */
-  char **azColumn;         /* Original names of columns to be indexed */
-  char **azContentColumn;  /* Column names for %_content */
-  char **azTokenizer;      /* Name of tokenizer and its arguments */
-} TableSpec;
+static int fts3DisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int i;
 
-/*
-** Reclaim all of the memory used by a TableSpec
-*/
-static void clearTableSpec(TableSpec *p) {
-  sqlite3_free(p->azColumn);
-  sqlite3_free(p->azContentColumn);
-  sqlite3_free(p->azTokenizer);
-}
+  assert( p->nPendingData==0 );
+  assert( p->pSegments==0 );
 
-/* Parse a CREATE VIRTUAL TABLE statement, which looks like this:
- *
- * CREATE VIRTUAL TABLE email
- *        USING fts3(subject, body, tokenize mytokenizer(myarg))
- *
- * We return parsed information in a TableSpec structure.
- * 
- */
-static int parseSpec(TableSpec *pSpec, int argc, const char *const*argv,
-                     char**pzErr){
-  int i, n;
-  char *z, *zDummy;
-  char **azArg;
-  const char *zTokenizer = 0;    /* argv[] entry describing the tokenizer */
-
-  assert( argc>=3 );
-  /* Current interface:
-  ** argv[0] - module name
-  ** argv[1] - database name
-  ** argv[2] - table name
-  ** argv[3..] - columns, optionally followed by tokenizer specification
-  **             and snippet delimiters specification.
-  */
-
-  /* Make a copy of the complete argv[][] array in a single allocation.
-  ** The argv[][] array is read-only and transient.  We can write to the
-  ** copy in order to modify things and the copy is persistent.
-  */
-  CLEAR(pSpec);
-  for(i=n=0; i<argc; i++){
-    n += strlen(argv[i]) + 1;
-  }
-  azArg = sqlite3_malloc( sizeof(char*)*argc + n );
-  if( azArg==0 ){
-    return SQLITE_NOMEM;
-  }
-  z = (char*)&azArg[argc];
-  for(i=0; i<argc; i++){
-    azArg[i] = z;
-    strcpy(z, argv[i]);
-    z += strlen(z)+1;
+  /* Free any prepared statements held */
+  for(i=0; i<SizeofArray(p->aStmt); i++){
+    sqlite3_finalize(p->aStmt[i]);
   }
+  sqlite3_free(p->zSegmentsTbl);
+  sqlite3_free(p->zReadExprlist);
+  sqlite3_free(p->zWriteExprlist);
+  sqlite3_free(p->zContentTbl);
+  sqlite3_free(p->zLanguageid);
 
-  /* Identify the column names and the tokenizer and delimiter arguments
-  ** in the argv[][] array.
-  */
-  pSpec->zDb = azArg[1];
-  pSpec->zName = azArg[2];
-  pSpec->nColumn = 0;
-  pSpec->azColumn = azArg;
-  zTokenizer = "tokenize simple";
-  for(i=3; i<argc; ++i){
-    if( startsWith(azArg[i],"tokenize") ){
-      zTokenizer = azArg[i];
-    }else{
-      z = azArg[pSpec->nColumn] = firstToken(azArg[i], &zDummy);
-      pSpec->nColumn++;
-    }
-  }
-  if( pSpec->nColumn==0 ){
-    azArg[0] = "content";
-    pSpec->nColumn = 1;
-  }
-
-  /*
-  ** Construct the list of content column names.
-  **
-  ** Each content column name will be of the form cNNAAAA
-  ** where NN is the column number and AAAA is the sanitized
-  ** column name.  "sanitized" means that special characters are
-  ** converted to "_".  The cNN prefix guarantees that all column
-  ** names are unique.
-  **
-  ** The AAAA suffix is not strictly necessary.  It is included
-  ** for the convenience of people who might examine the generated
-  ** %_content table and wonder what the columns are used for.
-  */
-  pSpec->azContentColumn = sqlite3_malloc( pSpec->nColumn * sizeof(char *) );
-  if( pSpec->azContentColumn==0 ){
-    clearTableSpec(pSpec);
-    return SQLITE_NOMEM;
-  }
-  for(i=0; i<pSpec->nColumn; i++){
-    char *p;
-    pSpec->azContentColumn[i] = sqlite3_mprintf("c%d%s", i, azArg[i]);
-    for (p = pSpec->azContentColumn[i]; *p ; ++p) {
-      if( !safe_isalnum(*p) ) *p = '_';
-    }
-  }
-
-  /*
-  ** Parse the tokenizer specification string.
-  */
-  pSpec->azTokenizer = tokenizeString(zTokenizer, &n);
-  tokenListToIdList(pSpec->azTokenizer);
+  /* Invoke the tokenizer destructor to free the tokenizer. */
+  p->pTokenizer->pModule->xDestroy(p->pTokenizer);
 
+  sqlite3_free(p);
   return SQLITE_OK;
 }
 
 /*
-** Generate a CREATE TABLE statement that describes the schema of
-** the virtual table.  Return a pointer to this schema string.
+** Construct one or more SQL statements from the format string given
+** and then evaluate those statements. The success code is written
+** into *pRc.
 **
-** Space is obtained from sqlite3_mprintf() and should be freed
-** using sqlite3_free().
+** If *pRc is initially non-zero then this routine is a no-op.
 */
-static char *fulltextSchema(
-  int nColumn,                  /* Number of columns */
-  const char *const* azColumn,  /* List of columns */
-  const char *zTableName        /* Name of the table */
+static void fts3DbExec(
+  int *pRc,              /* Success code */
+  sqlite3 *db,           /* Database in which to run SQL */
+  const char *zFormat,   /* Format string for SQL */
+  ...                    /* Arguments to the format string */
 ){
-  int i;
-  char *zSchema, *zNext;
-  const char *zSep = "(";
-  zSchema = sqlite3_mprintf("CREATE TABLE x");
-  for(i=0; i<nColumn; i++){
-    zNext = sqlite3_mprintf("%s%s%Q", zSchema, zSep, azColumn[i]);
-    sqlite3_free(zSchema);
-    zSchema = zNext;
-    zSep = ",";
-  }
-  zNext = sqlite3_mprintf("%s,%Q HIDDEN", zSchema, zTableName);
-  sqlite3_free(zSchema);
-  zSchema = zNext;
-  zNext = sqlite3_mprintf("%s,docid HIDDEN)", zSchema);
-  sqlite3_free(zSchema);
-  return zNext;
-}
-
-/*
-** Build a new sqlite3_vtab structure that will describe the
-** fulltext index defined by spec.
-*/
-static int constructVtab(
-  sqlite3 *db,              /* The SQLite database connection */
-  fts3Hash *pHash,          /* Hash table containing tokenizers */
-  TableSpec *spec,          /* Parsed spec information from parseSpec() */
-  sqlite3_vtab **ppVTab,    /* Write the resulting vtab structure here */
-  char **pzErr              /* Write any error message here */
-){
-  int rc;
-  int n;
-  fulltext_vtab *v = 0;
-  const sqlite3_tokenizer_module *m = NULL;
-  char *schema;
-
-  char const *zTok;         /* Name of tokenizer to use for this fts table */
-  int nTok;                 /* Length of zTok, including nul terminator */
-
-  v = (fulltext_vtab *) sqlite3_malloc(sizeof(fulltext_vtab));
-  if( v==0 ) return SQLITE_NOMEM;
-  CLEAR(v);
-  /* sqlite will initialize v->base */
-  v->db = db;
-  v->zDb = spec->zDb;       /* Freed when azColumn is freed */
-  v->zName = spec->zName;   /* Freed when azColumn is freed */
-  v->nColumn = spec->nColumn;
-  v->azContentColumn = spec->azContentColumn;
-  spec->azContentColumn = 0;
-  v->azColumn = spec->azColumn;
-  spec->azColumn = 0;
-
-  if( spec->azTokenizer==0 ){
-    return SQLITE_NOMEM;
-  }
-
-  zTok = spec->azTokenizer[0]; 
-  if( !zTok ){
-    zTok = "simple";
-  }
-  nTok = strlen(zTok)+1;
-
-  m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zTok, nTok);
-  if( !m ){
-    *pzErr = sqlite3_mprintf("unknown tokenizer: %s", spec->azTokenizer[0]);
-    rc = SQLITE_ERROR;
-    goto err;
-  }
-
-  for(n=0; spec->azTokenizer[n]; n++){}
-  if( n ){
-    rc = m->xCreate(n-1, (const char*const*)&spec->azTokenizer[1],
-                    &v->pTokenizer);
+  va_list ap;
+  char *zSql;
+  if( *pRc ) return;
+  va_start(ap, zFormat);
+  zSql = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+  if( zSql==0 ){
+    *pRc = SQLITE_NOMEM;
   }else{
-    rc = m->xCreate(0, 0, &v->pTokenizer);
+    *pRc = sqlite3_exec(db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
   }
-  if( rc!=SQLITE_OK ) goto err;
-  v->pTokenizer->pModule = m;
-
-  /* TODO: verify the existence of backing tables foo_content, foo_term */
-
-  schema = fulltextSchema(v->nColumn, (const char*const*)v->azColumn,
-                          spec->zName);
-  rc = sqlite3_declare_vtab(db, schema);
-  sqlite3_free(schema);
-  if( rc!=SQLITE_OK ) goto err;
-
-  memset(v->pFulltextStatements, 0, sizeof(v->pFulltextStatements));
-
-  /* Indicate that the buffer is not live. */
-  v->nPendingData = -1;
-
-  *ppVTab = &v->base;
-  FTSTRACE(("FTS3 Connect %p\n", v));
-
-  return rc;
-
-err:
-  fulltext_vtab_destroy(v);
-  return rc;
-}
-
-static int fulltextConnect(
-  sqlite3 *db,
-  void *pAux,
-  int argc, const char *const*argv,
-  sqlite3_vtab **ppVTab,
-  char **pzErr
-){
-  TableSpec spec;
-  int rc = parseSpec(&spec, argc, argv, pzErr);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = constructVtab(db, (fts3Hash *)pAux, &spec, ppVTab, pzErr);
-  clearTableSpec(&spec);
-  return rc;
-}
-
-/* The %_content table holds the text of each document, with
-** the docid column exposed as the SQLite rowid for the table.
-*/
-/* TODO(shess) This comment needs elaboration to match the updated
-** code.  Work it into the top-of-file comment at that time.
-*/
-static int fulltextCreate(sqlite3 *db, void *pAux,
-                          int argc, const char * const *argv,
-                          sqlite3_vtab **ppVTab, char **pzErr){
-  int rc;
-  TableSpec spec;
-  StringBuffer schema;
-  FTSTRACE(("FTS3 Create\n"));
-
-  rc = parseSpec(&spec, argc, argv, pzErr);
-  if( rc!=SQLITE_OK ) return rc;
-
-  initStringBuffer(&schema);
-  append(&schema, "CREATE TABLE %_content(");
-  append(&schema, "  docid INTEGER PRIMARY KEY,");
-  appendList(&schema, spec.nColumn, spec.azContentColumn);
-  append(&schema, ")");
-  rc = sql_exec(db, spec.zDb, spec.zName, stringBufferData(&schema));
-  stringBufferDestroy(&schema);
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = sql_exec(db, spec.zDb, spec.zName,
-                "create table %_segments("
-                "  blockid INTEGER PRIMARY KEY,"
-                "  block blob"
-                ");"
-                );
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = sql_exec(db, spec.zDb, spec.zName,
-                "create table %_segdir("
-                "  level integer,"
-                "  idx integer,"
-                "  start_block integer,"
-                "  leaves_end_block integer,"
-                "  end_block integer,"
-                "  root blob,"
-                "  primary key(level, idx)"
-                ");");
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = constructVtab(db, (fts3Hash *)pAux, &spec, ppVTab, pzErr);
-
-out:
-  clearTableSpec(&spec);
-  return rc;
-}
-
-/* Decide how to handle an SQL query. */
-static int fulltextBestIndex(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
-  fulltext_vtab *v = (fulltext_vtab *)pVTab;
-  int i;
-  FTSTRACE(("FTS3 BestIndex\n"));
-
-  for(i=0; i<pInfo->nConstraint; ++i){
-    const struct sqlite3_index_constraint *pConstraint;
-    pConstraint = &pInfo->aConstraint[i];
-    if( pConstraint->usable ) {
-      if( (pConstraint->iColumn==-1 || pConstraint->iColumn==v->nColumn+1) &&
-          pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){
-        pInfo->idxNum = QUERY_DOCID;      /* lookup by docid */
-        FTSTRACE(("FTS3 QUERY_DOCID\n"));
-      } else if( pConstraint->iColumn>=0 && pConstraint->iColumn<=v->nColumn &&
-                 pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH ){
-        /* full-text search */
-        pInfo->idxNum = QUERY_FULLTEXT + pConstraint->iColumn;
-        FTSTRACE(("FTS3 QUERY_FULLTEXT %d\n", pConstraint->iColumn));
-      } else continue;
-
-      pInfo->aConstraintUsage[i].argvIndex = 1;
-      pInfo->aConstraintUsage[i].omit = 1;
-
-      /* An arbitrary value for now.
-       * TODO: Perhaps docid matches should be considered cheaper than
-       * full-text searches. */
-      pInfo->estimatedCost = 1.0;   
-
-      return SQLITE_OK;
-    }
-  }
-  pInfo->idxNum = QUERY_GENERIC;
-  return SQLITE_OK;
-}
-
-static int fulltextDisconnect(sqlite3_vtab *pVTab){
-  FTSTRACE(("FTS3 Disconnect %p\n", pVTab));
-  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
-  return SQLITE_OK;
-}
-
-static int fulltextDestroy(sqlite3_vtab *pVTab){
-  fulltext_vtab *v = (fulltext_vtab *)pVTab;
-  int rc;
-
-  FTSTRACE(("FTS3 Destroy %p\n", pVTab));
-  rc = sql_exec(v->db, v->zDb, v->zName,
-                "drop table if exists %_content;"
-                "drop table if exists %_segments;"
-                "drop table if exists %_segdir;"
-                );
-  if( rc!=SQLITE_OK ) return rc;
-
-  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
-  return SQLITE_OK;
-}
-
-static int fulltextOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
-  fulltext_cursor *c;
-
-  c = (fulltext_cursor *) sqlite3_malloc(sizeof(fulltext_cursor));
-  if( c ){
-    memset(c, 0, sizeof(fulltext_cursor));
-    /* sqlite will initialize c->base */
-    *ppCursor = &c->base;
-    FTSTRACE(("FTS3 Open %p: %p\n", pVTab, c));
-    return SQLITE_OK;
-  }else{
-    return SQLITE_NOMEM;
-  }
-}
-
-/* Free all of the dynamically allocated memory held by the
-** Snippet
-*/
-static void snippetClear(Snippet *p){
-  sqlite3_free(p->aMatch);
-  sqlite3_free(p->zOffset);
-  sqlite3_free(p->zSnippet);
-  CLEAR(p);
 }
 
 /*
-** Append a single entry to the p->aMatch[] log.
+** The xDestroy() virtual table method.
 */
-static void snippetAppendMatch(
-  Snippet *p,               /* Append the entry to this snippet */
-  int iCol, int iTerm,      /* The column and query term */
-  int iToken,               /* Matching token in document */
-  int iStart, int nByte     /* Offset and size of the match */
-){
-  int i;
-  struct snippetMatch *pMatch;
-  if( p->nMatch+1>=p->nAlloc ){
-    p->nAlloc = p->nAlloc*2 + 10;
-    p->aMatch = sqlite3_realloc(p->aMatch, p->nAlloc*sizeof(p->aMatch[0]) );
-    if( p->aMatch==0 ){
-      p->nMatch = 0;
-      p->nAlloc = 0;
-      return;
-    }
+static int fts3DestroyMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_OK;              /* Return code */
+  const char *zDb = p->zDb;        /* Name of database (e.g. "main", "temp") */
+  sqlite3 *db = p->db;             /* Database handle */
+
+  /* Drop the shadow tables */
+  if( p->zContentTbl==0 ){
+    fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_content'", zDb, p->zName);
   }
-  i = p->nMatch++;
-  pMatch = &p->aMatch[i];
-  pMatch->iCol = iCol;
-  pMatch->iTerm = iTerm;
-  pMatch->iToken = iToken;
-  pMatch->iStart = iStart;
-  pMatch->nByte = nByte;
+  fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_segments'", zDb,p->zName);
+  fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_segdir'", zDb, p->zName);
+  fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_docsize'", zDb, p->zName);
+  fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_stat'", zDb, p->zName);
+
+  /* If everything has worked, invoke fts3DisconnectMethod() to free the
+  ** memory associated with the Fts3Table structure and return SQLITE_OK.
+  ** Otherwise, return an SQLite error code.
+  */
+  return (rc==SQLITE_OK ? fts3DisconnectMethod(pVtab) : rc);
 }
 
-/*
-** Sizing information for the circular buffer used in snippetOffsetsOfColumn()
-*/
-#define FTS3_ROTOR_SZ   (32)
-#define FTS3_ROTOR_MASK (FTS3_ROTOR_SZ-1)
 
 /*
-** Function to iterate through the tokens of a compiled expression.
+** Invoke sqlite3_declare_vtab() to declare the schema for the FTS3 table
+** passed as the first argument. This is done as part of the xConnect()
+** and xCreate() methods.
 **
-** Except, skip all tokens on the right-hand side of a NOT operator.
-** This function is used to find tokens as part of snippet and offset
-** generation and we do nt want snippets and offsets to report matches
-** for tokens on the RHS of a NOT.
+** If *pRc is non-zero when this function is called, it is a no-op. 
+** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
+** before returning.
 */
-static int fts3NextExprToken(Fts3Expr **ppExpr, int *piToken){
-  Fts3Expr *p = *ppExpr;
-  int iToken = *piToken;
-  if( iToken<0 ){
-    /* In this case the expression p is the root of an expression tree.
-    ** Move to the first token in the expression tree.
-    */
-    while( p->pLeft ){
-      p = p->pLeft;
+static void fts3DeclareVtab(int *pRc, Fts3Table *p){
+  if( *pRc==SQLITE_OK ){
+    int i;                        /* Iterator variable */
+    int rc;                       /* Return code */
+    char *zSql;                   /* SQL statement passed to declare_vtab() */
+    char *zCols;                  /* List of user defined columns */
+    const char *zLanguageid;
+
+    zLanguageid = (p->zLanguageid ? p->zLanguageid : "__langid");
+    sqlite3_vtab_config(p->db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
+
+    /* Create a list of user columns for the virtual table */
+    zCols = sqlite3_mprintf("%Q, ", p->azColumn[0]);
+    for(i=1; zCols && i<p->nColumn; i++){
+      zCols = sqlite3_mprintf("%z%Q, ", zCols, p->azColumn[i]);
     }
-    iToken = 0;
-  }else{
-    assert(p && p->eType==FTSQUERY_PHRASE );
-    if( iToken<(p->pPhrase->nToken-1) ){
-      iToken++;
+
+    /* Create the whole "CREATE TABLE" statement to pass to SQLite */
+    zSql = sqlite3_mprintf(
+        "CREATE TABLE x(%s %Q HIDDEN, docid HIDDEN, %Q HIDDEN)", 
+        zCols, p->zName, zLanguageid
+    );
+    if( !zCols || !zSql ){
+      rc = SQLITE_NOMEM;
     }else{
-      iToken = 0;
-      while( p->pParent && p->pParent->pLeft!=p ){
-        assert( p->pParent->pRight==p );
-        p = p->pParent;
-      }
-      p = p->pParent;
-      if( p ){
-        assert( p->pRight!=0 );
-        p = p->pRight;
-        while( p->pLeft ){
-          p = p->pLeft;
-        }
-      }
+      rc = sqlite3_declare_vtab(p->db, zSql);
     }
-  }
 
-  *ppExpr = p;
-  *piToken = iToken;
-  return p?1:0;
+    sqlite3_free(zSql);
+    sqlite3_free(zCols);
+    *pRc = rc;
+  }
 }
 
 /*
-** Return TRUE if the expression node pExpr is located beneath the
-** RHS of a NOT operator.
+** Create the %_stat table if it does not already exist.
 */
-static int fts3ExprBeneathNot(Fts3Expr *p){
-  Fts3Expr *pParent;
-  while( p ){
-    pParent = p->pParent;
-    if( pParent && pParent->eType==FTSQUERY_NOT && pParent->pRight==p ){
-      return 1;
-    }
-    p = pParent;
-  }
-  return 0;
+SQLITE_PRIVATE void sqlite3Fts3CreateStatTable(int *pRc, Fts3Table *p){
+  fts3DbExec(pRc, p->db, 
+      "CREATE TABLE IF NOT EXISTS %Q.'%q_stat'"
+          "(id INTEGER PRIMARY KEY, value BLOB);",
+      p->zDb, p->zName
+  );
+  if( (*pRc)==SQLITE_OK ) p->bHasStat = 1;
 }
 
 /*
-** Add entries to pSnippet->aMatch[] for every match that occurs against
-** document zDoc[0..nDoc-1] which is stored in column iColumn.
-*/
-static void snippetOffsetsOfColumn(
-  fulltext_cursor *pCur,         /* The fulltest search cursor */
-  Snippet *pSnippet,             /* The Snippet object to be filled in */
-  int iColumn,                   /* Index of fulltext table column */
-  const char *zDoc,              /* Text of the fulltext table column */
-  int nDoc                       /* Length of zDoc in bytes */
-){
-  const sqlite3_tokenizer_module *pTModule;  /* The tokenizer module */
-  sqlite3_tokenizer *pTokenizer;             /* The specific tokenizer */
-  sqlite3_tokenizer_cursor *pTCursor;        /* Tokenizer cursor */
-  fulltext_vtab *pVtab;                /* The full text index */
-  int nColumn;                         /* Number of columns in the index */
-  int i, j;                            /* Loop counters */
-  int rc;                              /* Return code */
-  unsigned int match, prevMatch;       /* Phrase search bitmasks */
-  const char *zToken;                  /* Next token from the tokenizer */
-  int nToken;                          /* Size of zToken */
-  int iBegin, iEnd, iPos;              /* Offsets of beginning and end */
-
-  /* The following variables keep a circular buffer of the last
-  ** few tokens */
-  unsigned int iRotor = 0;             /* Index of current token */
-  int iRotorBegin[FTS3_ROTOR_SZ];      /* Beginning offset of token */
-  int iRotorLen[FTS3_ROTOR_SZ];        /* Length of token */
-
-  pVtab = cursor_vtab(pCur);
-  nColumn = pVtab->nColumn;
-  pTokenizer = pVtab->pTokenizer;
-  pTModule = pTokenizer->pModule;
-  rc = pTModule->xOpen(pTokenizer, zDoc, nDoc, &pTCursor);
-  if( rc ) return;
-  pTCursor->pTokenizer = pTokenizer;
-
-  prevMatch = 0;
-  while( !pTModule->xNext(pTCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos) ){
-    Fts3Expr *pIter = pCur->pExpr;
-    int iIter = -1;
-    iRotorBegin[iRotor&FTS3_ROTOR_MASK] = iBegin;
-    iRotorLen[iRotor&FTS3_ROTOR_MASK] = iEnd-iBegin;
-    match = 0;
-    for(i=0; i<(FTS3_ROTOR_SZ-1) && fts3NextExprToken(&pIter, &iIter); i++){
-      int nPhrase;                    /* Number of tokens in current phrase */
-      struct PhraseToken *pToken;     /* Current token */
-      int iCol;                       /* Column index */
-
-      if( fts3ExprBeneathNot(pIter) ) continue;
-      nPhrase = pIter->pPhrase->nToken;
-      pToken = &pIter->pPhrase->aToken[iIter];
-      iCol = pIter->pPhrase->iColumn;
-      if( iCol>=0 && iCol<nColumn && iCol!=iColumn ) continue;
-      if( pToken->n>nToken ) continue;
-      if( !pToken->isPrefix && pToken->n<nToken ) continue;
-      assert( pToken->n<=nToken );
-      if( memcmp(pToken->z, zToken, pToken->n) ) continue;
-      if( iIter>0 && (prevMatch & (1<<i))==0 ) continue;
-      match |= 1<<i;
-      if( i==(FTS3_ROTOR_SZ-2) || nPhrase==iIter+1 ){
-        for(j=nPhrase-1; j>=0; j--){
-          int k = (iRotor-j) & FTS3_ROTOR_MASK;
-          snippetAppendMatch(pSnippet, iColumn, i-j, iPos-j,
-                iRotorBegin[k], iRotorLen[k]);
-        }
-      }
-    }
-    prevMatch = match<<1;
-    iRotor++;
-  }
-  pTModule->xClose(pTCursor);  
-}
-
-/*
-** Remove entries from the pSnippet structure to account for the NEAR
-** operator. When this is called, pSnippet contains the list of token 
-** offsets produced by treating all NEAR operators as AND operators.
-** This function removes any entries that should not be present after
-** accounting for the NEAR restriction. For example, if the queried
-** document is:
+** Create the backing store tables (%_content, %_segments and %_segdir)
+** required by the FTS3 table passed as the only argument. This is done
+** as part of the vtab xCreate() method.
 **
-**     "A B C D E A"
-**
-** and the query is:
-** 
-**     A NEAR/0 E
-**
-** then when this function is called the Snippet contains token offsets
-** 0, 4 and 5. This function removes the "0" entry (because the first A
-** is not near enough to an E).
-**
-** When this function is called, the value pointed to by parameter piLeft is
-** the integer id of the left-most token in the expression tree headed by
-** pExpr. This function increments *piLeft by the total number of tokens
-** in the expression tree headed by pExpr.
-**
-** Return 1 if any trimming occurs.  Return 0 if no trimming is required.
+** If the p->bHasDocsize boolean is true (indicating that this is an
+** FTS4 table, not an FTS3 table) then also create the %_docsize and
+** %_stat tables required by FTS4.
 */
-static int trimSnippetOffsets(
-  Fts3Expr *pExpr,      /* The search expression */
-  Snippet *pSnippet,    /* The set of snippet offsets to be trimmed */
-  int *piLeft           /* Index of left-most token in pExpr */
-){
-  if( pExpr ){
-    if( trimSnippetOffsets(pExpr->pLeft, pSnippet, piLeft) ){
-      return 1;
+static int fts3CreateTables(Fts3Table *p){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Iterator variable */
+  sqlite3 *db = p->db;            /* The database connection */
+
+  if( p->zContentTbl==0 ){
+    const char *zLanguageid = p->zLanguageid;
+    char *zContentCols;           /* Columns of %_content table */
+
+    /* Create a list of user columns for the content table */
+    zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY");
+    for(i=0; zContentCols && i<p->nColumn; i++){
+      char *z = p->azColumn[i];
+      zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i, z);
     }
-
-    switch( pExpr->eType ){
-      case FTSQUERY_PHRASE:
-        *piLeft += pExpr->pPhrase->nToken;
-        break;
-      case FTSQUERY_NEAR: {
-        /* The right-hand-side of a NEAR operator is always a phrase. The
-        ** left-hand-side is either a phrase or an expression tree that is 
-        ** itself headed by a NEAR operator. The following initializations
-        ** set local variable iLeft to the token number of the left-most
-        ** token in the right-hand phrase, and iRight to the right most
-        ** token in the same phrase. For example, if we had:
-        **
-        **     <col> MATCH '"abc def" NEAR/2 "ghi jkl"'
-        **
-        ** then iLeft will be set to 2 (token number of ghi) and nToken will
-        ** be set to 4.
-        */
-        Fts3Expr *pLeft = pExpr->pLeft;
-        Fts3Expr *pRight = pExpr->pRight;
-        int iLeft = *piLeft;
-        int nNear = pExpr->nNear;
-        int nToken = pRight->pPhrase->nToken;
-        int jj, ii;
-        if( pLeft->eType==FTSQUERY_NEAR ){
-          pLeft = pLeft->pRight;
-        }
-        assert( pRight->eType==FTSQUERY_PHRASE );
-        assert( pLeft->eType==FTSQUERY_PHRASE );
-        nToken += pLeft->pPhrase->nToken;
-
-        for(ii=0; ii<pSnippet->nMatch; ii++){
-          struct snippetMatch *p = &pSnippet->aMatch[ii];
-          if( p->iTerm==iLeft ){
-            int isOk = 0;
-            /* Snippet ii is an occurence of query term iLeft in the document.
-            ** It occurs at position (p->iToken) of the document. We now
-            ** search for an instance of token (iLeft-1) somewhere in the 
-            ** range (p->iToken - nNear)...(p->iToken + nNear + nToken) within 
-            ** the set of snippetMatch structures. If one is found, proceed. 
-            ** If one cannot be found, then remove snippets ii..(ii+N-1) 
-            ** from the matching snippets, where N is the number of tokens 
-            ** in phrase pRight->pPhrase.
-            */
-            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
-              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
-              if( p2->iTerm==(iLeft-1) ){
-                if( p2->iToken>=(p->iToken-nNear-1) 
-                 && p2->iToken<(p->iToken+nNear+nToken) 
-                ){
-                  isOk = 1;
-                }
-              }
-            }
-            if( !isOk ){
-              int kk;
-              for(kk=0; kk<pRight->pPhrase->nToken; kk++){
-                pSnippet->aMatch[kk+ii].iTerm = -2;
-              }
-              return 1;
-            }
-          }
-          if( p->iTerm==(iLeft-1) ){
-            int isOk = 0;
-            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
-              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
-              if( p2->iTerm==iLeft ){
-                if( p2->iToken<=(p->iToken+nNear+1) 
-                 && p2->iToken>(p->iToken-nNear-nToken) 
-                ){
-                  isOk = 1;
-                }
-              }
-            }
-            if( !isOk ){
-              int kk;
-              for(kk=0; kk<pLeft->pPhrase->nToken; kk++){
-                pSnippet->aMatch[ii-kk].iTerm = -2;
-              }
-              return 1;
-            }
-          }
-        }
-        break;
-      }
+    if( zLanguageid && zContentCols ){
+      zContentCols = sqlite3_mprintf("%z, langid", zContentCols, zLanguageid);
     }
-
-    if( trimSnippetOffsets(pExpr->pRight, pSnippet, piLeft) ){
-      return 1;
-    }
-  }
-  return 0;
-}
-
-/*
-** Compute all offsets for the current row of the query.  
-** If the offsets have already been computed, this routine is a no-op.
-*/
-static void snippetAllOffsets(fulltext_cursor *p){
-  int nColumn;
-  int iColumn, i;
-  int iFirst, iLast;
-  int iTerm = 0;
-  fulltext_vtab *pFts = cursor_vtab(p);
-
-  if( p->snippet.nMatch || p->pExpr==0 ){
-    return;
-  }
-  nColumn = pFts->nColumn;
-  iColumn = (p->iCursorType - QUERY_FULLTEXT);
-  if( iColumn<0 || iColumn>=nColumn ){
-    /* Look for matches over all columns of the full-text index */
-    iFirst = 0;
-    iLast = nColumn-1;
-  }else{
-    /* Look for matches in the iColumn-th column of the index only */
-    iFirst = iColumn;
-    iLast = iColumn;
-  }
-  for(i=iFirst; i<=iLast; i++){
-    const char *zDoc;
-    int nDoc;
-    zDoc = (const char*)sqlite3_column_text(p->pStmt, i+1);
-    nDoc = sqlite3_column_bytes(p->pStmt, i+1);
-    snippetOffsetsOfColumn(p, &p->snippet, i, zDoc, nDoc);
-  }
-
-  while( trimSnippetOffsets(p->pExpr, &p->snippet, &iTerm) ){
-    iTerm = 0;
-  }
-}
-
-/*
-** Convert the information in the aMatch[] array of the snippet
-** into the string zOffset[0..nOffset-1]. This string is used as
-** the return of the SQL offsets() function.
-*/
-static void snippetOffsetText(Snippet *p){
-  int i;
-  int cnt = 0;
-  StringBuffer sb;
-  char zBuf[200];
-  if( p->zOffset ) return;
-  initStringBuffer(&sb);
-  for(i=0; i<p->nMatch; i++){
-    struct snippetMatch *pMatch = &p->aMatch[i];
-    if( pMatch->iTerm>=0 ){
-      /* If snippetMatch.iTerm is less than 0, then the match was 
-      ** discarded as part of processing the NEAR operator (see the 
-      ** trimSnippetOffsetsForNear() function for details). Ignore 
-      ** it in this case
-      */
-      zBuf[0] = ' ';
-      sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
-          pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
-      append(&sb, zBuf);
-      cnt++;
-    }
-  }
-  p->zOffset = stringBufferData(&sb);
-  p->nOffset = stringBufferLength(&sb);
-}
-
-/*
-** zDoc[0..nDoc-1] is phrase of text.  aMatch[0..nMatch-1] are a set
-** of matching words some of which might be in zDoc.  zDoc is column
-** number iCol.
-**
-** iBreak is suggested spot in zDoc where we could begin or end an
-** excerpt.  Return a value similar to iBreak but possibly adjusted
-** to be a little left or right so that the break point is better.
-*/
-static int wordBoundary(
-  int iBreak,                   /* The suggested break point */
-  const char *zDoc,             /* Document text */
-  int nDoc,                     /* Number of bytes in zDoc[] */
-  struct snippetMatch *aMatch,  /* Matching words */
-  int nMatch,                   /* Number of entries in aMatch[] */
-  int iCol                      /* The column number for zDoc[] */
-){
-  int i;
-  if( iBreak<=10 ){
-    return 0;
-  }
-  if( iBreak>=nDoc-10 ){
-    return nDoc;
-  }
-  for(i=0; i<nMatch && aMatch[i].iCol<iCol; i++){}
-  while( i<nMatch && aMatch[i].iStart+aMatch[i].nByte<iBreak ){ i++; }
-  if( i<nMatch ){
-    if( aMatch[i].iStart<iBreak+10 ){
-      return aMatch[i].iStart;
-    }
-    if( i>0 && aMatch[i-1].iStart+aMatch[i-1].nByte>=iBreak ){
-      return aMatch[i-1].iStart;
-    }
-  }
-  for(i=1; i<=10; i++){
-    if( safe_isspace(zDoc[iBreak-i]) ){
-      return iBreak - i + 1;
-    }
-    if( safe_isspace(zDoc[iBreak+i]) ){
-      return iBreak + i + 1;
-    }
-  }
-  return iBreak;
-}
-
-
-
-/*
-** Allowed values for Snippet.aMatch[].snStatus
-*/
-#define SNIPPET_IGNORE  0   /* It is ok to omit this match from the snippet */
-#define SNIPPET_DESIRED 1   /* We want to include this match in the snippet */
-
-/*
-** Generate the text of a snippet.
-*/
-static void snippetText(
-  fulltext_cursor *pCursor,   /* The cursor we need the snippet for */
-  const char *zStartMark,     /* Markup to appear before each match */
-  const char *zEndMark,       /* Markup to appear after each match */
-  const char *zEllipsis       /* Ellipsis mark */
-){
-  int i, j;
-  struct snippetMatch *aMatch;
-  int nMatch;
-  int nDesired;
-  StringBuffer sb;
-  int tailCol;
-  int tailOffset;
-  int iCol;
-  int nDoc;
-  const char *zDoc;
-  int iStart, iEnd;
-  int tailEllipsis = 0;
-  int iMatch;
+    if( zContentCols==0 ) rc = SQLITE_NOMEM;
   
-
-  sqlite3_free(pCursor->snippet.zSnippet);
-  pCursor->snippet.zSnippet = 0;
-  aMatch = pCursor->snippet.aMatch;
-  nMatch = pCursor->snippet.nMatch;
-  initStringBuffer(&sb);
-
-  for(i=0; i<nMatch; i++){
-    aMatch[i].snStatus = SNIPPET_IGNORE;
-  }
-  nDesired = 0;
-  for(i=0; i<FTS3_ROTOR_SZ; i++){
-    for(j=0; j<nMatch; j++){
-      if( aMatch[j].iTerm==i ){
-        aMatch[j].snStatus = SNIPPET_DESIRED;
-        nDesired++;
-        break;
-      }
-    }
+    /* Create the content table */
+    fts3DbExec(&rc, db, 
+       "CREATE TABLE %Q.'%q_content'(%s)",
+       p->zDb, p->zName, zContentCols
+    );
+    sqlite3_free(zContentCols);
   }
 
-  iMatch = 0;
-  tailCol = -1;
-  tailOffset = 0;
-  for(i=0; i<nMatch && nDesired>0; i++){
-    if( aMatch[i].snStatus!=SNIPPET_DESIRED ) continue;
-    nDesired--;
-    iCol = aMatch[i].iCol;
-    zDoc = (const char*)sqlite3_column_text(pCursor->pStmt, iCol+1);
-    nDoc = sqlite3_column_bytes(pCursor->pStmt, iCol+1);
-    iStart = aMatch[i].iStart - 40;
-    iStart = wordBoundary(iStart, zDoc, nDoc, aMatch, nMatch, iCol);
-    if( iStart<=10 ){
-      iStart = 0;
-    }
-    if( iCol==tailCol && iStart<=tailOffset+20 ){
-      iStart = tailOffset;
-    }
-    if( (iCol!=tailCol && tailCol>=0) || iStart!=tailOffset ){
-      trimWhiteSpace(&sb);
-      appendWhiteSpace(&sb);
-      append(&sb, zEllipsis);
-      appendWhiteSpace(&sb);
-    }
-    iEnd = aMatch[i].iStart + aMatch[i].nByte + 40;
-    iEnd = wordBoundary(iEnd, zDoc, nDoc, aMatch, nMatch, iCol);
-    if( iEnd>=nDoc-10 ){
-      iEnd = nDoc;
-      tailEllipsis = 0;
-    }else{
-      tailEllipsis = 1;
-    }
-    while( iMatch<nMatch && aMatch[iMatch].iCol<iCol ){ iMatch++; }
-    while( iStart<iEnd ){
-      while( iMatch<nMatch && aMatch[iMatch].iStart<iStart
-             && aMatch[iMatch].iCol<=iCol ){
-        iMatch++;
-      }
-      if( iMatch<nMatch && aMatch[iMatch].iStart<iEnd
-             && aMatch[iMatch].iCol==iCol ){
-        nappend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
-        iStart = aMatch[iMatch].iStart;
-        append(&sb, zStartMark);
-        nappend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
-        append(&sb, zEndMark);
-        iStart += aMatch[iMatch].nByte;
-        for(j=iMatch+1; j<nMatch; j++){
-          if( aMatch[j].iTerm==aMatch[iMatch].iTerm
-              && aMatch[j].snStatus==SNIPPET_DESIRED ){
-            nDesired--;
-            aMatch[j].snStatus = SNIPPET_IGNORE;
-          }
-        }
-      }else{
-        nappend(&sb, &zDoc[iStart], iEnd - iStart);
-        iStart = iEnd;
-      }
-    }
-    tailCol = iCol;
-    tailOffset = iEnd;
+  /* Create other tables */
+  fts3DbExec(&rc, db, 
+      "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);",
+      p->zDb, p->zName
+  );
+  fts3DbExec(&rc, db, 
+      "CREATE TABLE %Q.'%q_segdir'("
+        "level INTEGER,"
+        "idx INTEGER,"
+        "start_block INTEGER,"
+        "leaves_end_block INTEGER,"
+        "end_block INTEGER,"
+        "root BLOB,"
+        "PRIMARY KEY(level, idx)"
+      ");",
+      p->zDb, p->zName
+  );
+  if( p->bHasDocsize ){
+    fts3DbExec(&rc, db, 
+        "CREATE TABLE %Q.'%q_docsize'(docid INTEGER PRIMARY KEY, size BLOB);",
+        p->zDb, p->zName
+    );
   }
-  trimWhiteSpace(&sb);
-  if( tailEllipsis ){
-    appendWhiteSpace(&sb);
-    append(&sb, zEllipsis);
+  assert( p->bHasStat==p->bFts4 );
+  if( p->bHasStat ){
+    sqlite3Fts3CreateStatTable(&rc, p);
   }
-  pCursor->snippet.zSnippet = stringBufferData(&sb);
-  pCursor->snippet.nSnippet = stringBufferLength(&sb);
+  return rc;
 }
 
+/*
+** Store the current database page-size in bytes in p->nPgsz.
+**
+** If *pRc is non-zero when this function is called, it is a no-op. 
+** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
+** before returning.
+*/
+static void fts3DatabasePageSize(int *pRc, Fts3Table *p){
+  if( *pRc==SQLITE_OK ){
+    int rc;                       /* Return code */
+    char *zSql;                   /* SQL text "PRAGMA %Q.page_size" */
+    sqlite3_stmt *pStmt;          /* Compiled "PRAGMA %Q.page_size" statement */
+  
+    zSql = sqlite3_mprintf("PRAGMA %Q.page_size", p->zDb);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare(p->db, zSql, -1, &pStmt, 0);
+      if( rc==SQLITE_OK ){
+        sqlite3_step(pStmt);
+        p->nPgsz = sqlite3_column_int(pStmt, 0);
+        rc = sqlite3_finalize(pStmt);
+      }else if( rc==SQLITE_AUTH ){
+        p->nPgsz = 1024;
+        rc = SQLITE_OK;
+      }
+    }
+    assert( p->nPgsz>0 || rc!=SQLITE_OK );
+    sqlite3_free(zSql);
+    *pRc = rc;
+  }
+}
+
+/*
+** "Special" FTS4 arguments are column specifications of the following form:
+**
+**   <key> = <value>
+**
+** There may not be whitespace surrounding the "=" character. The <value> 
+** term may be quoted, but the <key> may not.
+*/
+static int fts3IsSpecialColumn(
+  const char *z, 
+  int *pnKey,
+  char **pzValue
+){
+  char *zValue;
+  const char *zCsr = z;
+
+  while( *zCsr!='=' ){
+    if( *zCsr=='\0' ) return 0;
+    zCsr++;
+  }
+
+  *pnKey = (int)(zCsr-z);
+  zValue = sqlite3_mprintf("%s", &zCsr[1]);
+  if( zValue ){
+    sqlite3Fts3Dequote(zValue);
+  }
+  *pzValue = zValue;
+  return 1;
+}
+
+/*
+** Append the output of a printf() style formatting to an existing string.
+*/
+static void fts3Appendf(
+  int *pRc,                       /* IN/OUT: Error code */
+  char **pz,                      /* IN/OUT: Pointer to string buffer */
+  const char *zFormat,            /* Printf format string to append */
+  ...                             /* Arguments for printf format string */
+){
+  if( *pRc==SQLITE_OK ){
+    va_list ap;
+    char *z;
+    va_start(ap, zFormat);
+    z = sqlite3_vmprintf(zFormat, ap);
+    va_end(ap);
+    if( z && *pz ){
+      char *z2 = sqlite3_mprintf("%s%s", *pz, z);
+      sqlite3_free(z);
+      z = z2;
+    }
+    if( z==0 ) *pRc = SQLITE_NOMEM;
+    sqlite3_free(*pz);
+    *pz = z;
+  }
+}
+
+/*
+** Return a copy of input string zInput enclosed in double-quotes (") and
+** with all double quote characters escaped. For example:
+**
+**     fts3QuoteId("un \"zip\"")   ->    "un \"\"zip\"\""
+**
+** The pointer returned points to memory obtained from sqlite3_malloc(). It
+** is the callers responsibility to call sqlite3_free() to release this
+** memory.
+*/
+static char *fts3QuoteId(char const *zInput){
+  int nRet;
+  char *zRet;
+  nRet = 2 + (int)strlen(zInput)*2 + 1;
+  zRet = sqlite3_malloc(nRet);
+  if( zRet ){
+    int i;
+    char *z = zRet;
+    *(z++) = '"';
+    for(i=0; zInput[i]; i++){
+      if( zInput[i]=='"' ) *(z++) = '"';
+      *(z++) = zInput[i];
+    }
+    *(z++) = '"';
+    *(z++) = '\0';
+  }
+  return zRet;
+}
+
+/*
+** Return a list of comma separated SQL expressions and a FROM clause that 
+** could be used in a SELECT statement such as the following:
+**
+**     SELECT <list of expressions> FROM %_content AS x ...
+**
+** to return the docid, followed by each column of text data in order
+** from left to write. If parameter zFunc is not NULL, then instead of
+** being returned directly each column of text data is passed to an SQL
+** function named zFunc first. For example, if zFunc is "unzip" and the
+** table has the three user-defined columns "a", "b", and "c", the following
+** string is returned:
+**
+**     "docid, unzip(x.'a'), unzip(x.'b'), unzip(x.'c') FROM %_content AS x"
+**
+** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
+** is the responsibility of the caller to eventually free it.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
+** a NULL pointer is returned). Otherwise, if an OOM error is encountered
+** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
+** no error occurs, *pRc is left unmodified.
+*/
+static char *fts3ReadExprList(Fts3Table *p, const char *zFunc, int *pRc){
+  char *zRet = 0;
+  char *zFree = 0;
+  char *zFunction;
+  int i;
+
+  if( p->zContentTbl==0 ){
+    if( !zFunc ){
+      zFunction = "";
+    }else{
+      zFree = zFunction = fts3QuoteId(zFunc);
+    }
+    fts3Appendf(pRc, &zRet, "docid");
+    for(i=0; i<p->nColumn; i++){
+      fts3Appendf(pRc, &zRet, ",%s(x.'c%d%q')", zFunction, i, p->azColumn[i]);
+    }
+    if( p->zLanguageid ){
+      fts3Appendf(pRc, &zRet, ", x.%Q", "langid");
+    }
+    sqlite3_free(zFree);
+  }else{
+    fts3Appendf(pRc, &zRet, "rowid");
+    for(i=0; i<p->nColumn; i++){
+      fts3Appendf(pRc, &zRet, ", x.'%q'", p->azColumn[i]);
+    }
+    if( p->zLanguageid ){
+      fts3Appendf(pRc, &zRet, ", x.%Q", p->zLanguageid);
+    }
+  }
+  fts3Appendf(pRc, &zRet, " FROM '%q'.'%q%s' AS x", 
+      p->zDb,
+      (p->zContentTbl ? p->zContentTbl : p->zName),
+      (p->zContentTbl ? "" : "_content")
+  );
+  return zRet;
+}
+
+/*
+** Return a list of N comma separated question marks, where N is the number
+** of columns in the %_content table (one for the docid plus one for each
+** user-defined text column).
+**
+** If argument zFunc is not NULL, then all but the first question mark
+** is preceded by zFunc and an open bracket, and followed by a closed
+** bracket. For example, if zFunc is "zip" and the FTS3 table has three 
+** user-defined text columns, the following string is returned:
+**
+**     "?, zip(?), zip(?), zip(?)"
+**
+** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
+** is the responsibility of the caller to eventually free it.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
+** a NULL pointer is returned). Otherwise, if an OOM error is encountered
+** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
+** no error occurs, *pRc is left unmodified.
+*/
+static char *fts3WriteExprList(Fts3Table *p, const char *zFunc, int *pRc){
+  char *zRet = 0;
+  char *zFree = 0;
+  char *zFunction;
+  int i;
+
+  if( !zFunc ){
+    zFunction = "";
+  }else{
+    zFree = zFunction = fts3QuoteId(zFunc);
+  }
+  fts3Appendf(pRc, &zRet, "?");
+  for(i=0; i<p->nColumn; i++){
+    fts3Appendf(pRc, &zRet, ",%s(?)", zFunction);
+  }
+  if( p->zLanguageid ){
+    fts3Appendf(pRc, &zRet, ", ?");
+  }
+  sqlite3_free(zFree);
+  return zRet;
+}
+
+/*
+** This function interprets the string at (*pp) as a non-negative integer
+** value. It reads the integer and sets *pnOut to the value read, then 
+** sets *pp to point to the byte immediately following the last byte of
+** the integer value.
+**
+** Only decimal digits ('0'..'9') may be part of an integer value. 
+**
+** If *pp does not being with a decimal digit SQLITE_ERROR is returned and
+** the output value undefined. Otherwise SQLITE_OK is returned.
+**
+** This function is used when parsing the "prefix=" FTS4 parameter.
+*/
+static int fts3GobbleInt(const char **pp, int *pnOut){
+  const char *p;                  /* Iterator pointer */
+  int nInt = 0;                   /* Output value */
+
+  for(p=*pp; p[0]>='0' && p[0]<='9'; p++){
+    nInt = nInt * 10 + (p[0] - '0');
+  }
+  if( p==*pp ) return SQLITE_ERROR;
+  *pnOut = nInt;
+  *pp = p;
+  return SQLITE_OK;
+}
+
+/*
+** This function is called to allocate an array of Fts3Index structures
+** representing the indexes maintained by the current FTS table. FTS tables
+** always maintain the main "terms" index, but may also maintain one or
+** more "prefix" indexes, depending on the value of the "prefix=" parameter
+** (if any) specified as part of the CREATE VIRTUAL TABLE statement.
+**
+** Argument zParam is passed the value of the "prefix=" option if one was
+** specified, or NULL otherwise.
+**
+** If no error occurs, SQLITE_OK is returned and *apIndex set to point to
+** the allocated array. *pnIndex is set to the number of elements in the
+** array. If an error does occur, an SQLite error code is returned.
+**
+** Regardless of whether or not an error is returned, it is the responsibility
+** of the caller to call sqlite3_free() on the output array to free it.
+*/
+static int fts3PrefixParameter(
+  const char *zParam,             /* ABC in prefix=ABC parameter to parse */
+  int *pnIndex,                   /* OUT: size of *apIndex[] array */
+  struct Fts3Index **apIndex      /* OUT: Array of indexes for this table */
+){
+  struct Fts3Index *aIndex;       /* Allocated array */
+  int nIndex = 1;                 /* Number of entries in array */
+
+  if( zParam && zParam[0] ){
+    const char *p;
+    nIndex++;
+    for(p=zParam; *p; p++){
+      if( *p==',' ) nIndex++;
+    }
+  }
+
+  aIndex = sqlite3_malloc(sizeof(struct Fts3Index) * nIndex);
+  *apIndex = aIndex;
+  *pnIndex = nIndex;
+  if( !aIndex ){
+    return SQLITE_NOMEM;
+  }
+
+  memset(aIndex, 0, sizeof(struct Fts3Index) * nIndex);
+  if( zParam ){
+    const char *p = zParam;
+    int i;
+    for(i=1; i<nIndex; i++){
+      int nPrefix;
+      if( fts3GobbleInt(&p, &nPrefix) ) return SQLITE_ERROR;
+      aIndex[i].nPrefix = nPrefix;
+      p++;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** This function is called when initializing an FTS4 table that uses the
+** content=xxx option. It determines the number of and names of the columns
+** of the new FTS4 table.
+**
+** The third argument passed to this function is the value passed to the
+** config=xxx option (i.e. "xxx"). This function queries the database for
+** a table of that name. If found, the output variables are populated
+** as follows:
+**
+**   *pnCol:   Set to the number of columns table xxx has,
+**
+**   *pnStr:   Set to the total amount of space required to store a copy
+**             of each columns name, including the nul-terminator.
+**
+**   *pazCol:  Set to point to an array of *pnCol strings. Each string is
+**             the name of the corresponding column in table xxx. The array
+**             and its contents are allocated using a single allocation. It
+**             is the responsibility of the caller to free this allocation
+**             by eventually passing the *pazCol value to sqlite3_free().
+**
+** If the table cannot be found, an error code is returned and the output
+** variables are undefined. Or, if an OOM is encountered, SQLITE_NOMEM is
+** returned (and the output variables are undefined).
+*/
+static int fts3ContentColumns(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (i.e. "main", "temp" etc.) */
+  const char *zTbl,               /* Name of content table */
+  const char ***pazCol,           /* OUT: Malloc'd array of column names */
+  int *pnCol,                     /* OUT: Size of array *pazCol */
+  int *pnStr                      /* OUT: Bytes of string content */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  char *zSql;                     /* "SELECT *" statement on zTbl */  
+  sqlite3_stmt *pStmt = 0;        /* Compiled version of zSql */
+
+  zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", zDb, zTbl);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  }
+  sqlite3_free(zSql);
+
+  if( rc==SQLITE_OK ){
+    const char **azCol;           /* Output array */
+    int nStr = 0;                 /* Size of all column names (incl. 0x00) */
+    int nCol;                     /* Number of table columns */
+    int i;                        /* Used to iterate through columns */
+
+    /* Loop through the returned columns. Set nStr to the number of bytes of
+    ** space required to store a copy of each column name, including the
+    ** nul-terminator byte.  */
+    nCol = sqlite3_column_count(pStmt);
+    for(i=0; i<nCol; i++){
+      const char *zCol = sqlite3_column_name(pStmt, i);
+      nStr += (int)strlen(zCol) + 1;
+    }
+
+    /* Allocate and populate the array to return. */
+    azCol = (const char **)sqlite3_malloc(sizeof(char *) * nCol + nStr);
+    if( azCol==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      char *p = (char *)&azCol[nCol];
+      for(i=0; i<nCol; i++){
+        const char *zCol = sqlite3_column_name(pStmt, i);
+        int n = (int)strlen(zCol)+1;
+        memcpy(p, zCol, n);
+        azCol[i] = p;
+        p += n;
+      }
+    }
+    sqlite3_finalize(pStmt);
+
+    /* Set the output variables. */
+    *pnCol = nCol;
+    *pnStr = nStr;
+    *pazCol = azCol;
+  }
+
+  return rc;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts3" or "fts4")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" and other module argument fields.
+*/
+static int fts3InitVtab(
+  int isCreate,                   /* True for xCreate, false for xConnect */
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Hash table containing tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  Fts3Hash *pHash = (Fts3Hash *)pAux;
+  Fts3Table *p = 0;               /* Pointer to allocated vtab */
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Iterator variable */
+  int nByte;                      /* Size of allocation used for *p */
+  int iCol;                       /* Column index */
+  int nString = 0;                /* Bytes required to hold all column names */
+  int nCol = 0;                   /* Number of columns in the FTS table */
+  char *zCsr;                     /* Space for holding column names */
+  int nDb;                        /* Bytes required to hold database name */
+  int nName;                      /* Bytes required to hold table name */
+  int isFts4 = (argv[0][3]=='4'); /* True for FTS4, false for FTS3 */
+  const char **aCol;              /* Array of column names */
+  sqlite3_tokenizer *pTokenizer = 0;        /* Tokenizer for this table */
+
+  int nIndex;                     /* Size of aIndex[] array */
+  struct Fts3Index *aIndex = 0;   /* Array of indexes for this table */
+
+  /* The results of parsing supported FTS4 key=value options: */
+  int bNoDocsize = 0;             /* True to omit %_docsize table */
+  int bDescIdx = 0;               /* True to store descending indexes */
+  char *zPrefix = 0;              /* Prefix parameter value (or NULL) */
+  char *zCompress = 0;            /* compress=? parameter (or NULL) */
+  char *zUncompress = 0;          /* uncompress=? parameter (or NULL) */
+  char *zContent = 0;             /* content=? parameter (or NULL) */
+  char *zLanguageid = 0;          /* languageid=? parameter (or NULL) */
+
+  assert( strlen(argv[0])==4 );
+  assert( (sqlite3_strnicmp(argv[0], "fts4", 4)==0 && isFts4)
+       || (sqlite3_strnicmp(argv[0], "fts3", 4)==0 && !isFts4)
+  );
+
+  nDb = (int)strlen(argv[1]) + 1;
+  nName = (int)strlen(argv[2]) + 1;
+
+  aCol = (const char **)sqlite3_malloc(sizeof(const char *) * (argc-2) );
+  if( !aCol ) return SQLITE_NOMEM;
+  memset((void *)aCol, 0, sizeof(const char *) * (argc-2));
+
+  /* Loop through all of the arguments passed by the user to the FTS3/4
+  ** module (i.e. all the column names and special arguments). This loop
+  ** does the following:
+  **
+  **   + Figures out the number of columns the FTSX table will have, and
+  **     the number of bytes of space that must be allocated to store copies
+  **     of the column names.
+  **
+  **   + If there is a tokenizer specification included in the arguments,
+  **     initializes the tokenizer pTokenizer.
+  */
+  for(i=3; rc==SQLITE_OK && i<argc; i++){
+    char const *z = argv[i];
+    int nKey;
+    char *zVal;
+
+    /* Check if this is a tokenizer specification */
+    if( !pTokenizer 
+     && strlen(z)>8
+     && 0==sqlite3_strnicmp(z, "tokenize", 8) 
+     && 0==sqlite3Fts3IsIdChar(z[8])
+    ){
+      rc = sqlite3Fts3InitTokenizer(pHash, &z[9], &pTokenizer, pzErr);
+    }
+
+    /* Check if it is an FTS4 special argument. */
+    else if( isFts4 && fts3IsSpecialColumn(z, &nKey, &zVal) ){
+      struct Fts4Option {
+        const char *zOpt;
+        int nOpt;
+      } aFts4Opt[] = {
+        { "matchinfo",   9 },     /* 0 -> MATCHINFO */
+        { "prefix",      6 },     /* 1 -> PREFIX */
+        { "compress",    8 },     /* 2 -> COMPRESS */
+        { "uncompress", 10 },     /* 3 -> UNCOMPRESS */
+        { "order",       5 },     /* 4 -> ORDER */
+        { "content",     7 },     /* 5 -> CONTENT */
+        { "languageid", 10 }      /* 6 -> LANGUAGEID */
+      };
+
+      int iOpt;
+      if( !zVal ){
+        rc = SQLITE_NOMEM;
+      }else{
+        for(iOpt=0; iOpt<SizeofArray(aFts4Opt); iOpt++){
+          struct Fts4Option *pOp = &aFts4Opt[iOpt];
+          if( nKey==pOp->nOpt && !sqlite3_strnicmp(z, pOp->zOpt, pOp->nOpt) ){
+            break;
+          }
+        }
+        if( iOpt==SizeofArray(aFts4Opt) ){
+          *pzErr = sqlite3_mprintf("unrecognized parameter: %s", z);
+          rc = SQLITE_ERROR;
+        }else{
+          switch( iOpt ){
+            case 0:               /* MATCHINFO */
+              if( strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "fts3", 4) ){
+                *pzErr = sqlite3_mprintf("unrecognized matchinfo: %s", zVal);
+                rc = SQLITE_ERROR;
+              }
+              bNoDocsize = 1;
+              break;
+
+            case 1:               /* PREFIX */
+              sqlite3_free(zPrefix);
+              zPrefix = zVal;
+              zVal = 0;
+              break;
+
+            case 2:               /* COMPRESS */
+              sqlite3_free(zCompress);
+              zCompress = zVal;
+              zVal = 0;
+              break;
+
+            case 3:               /* UNCOMPRESS */
+              sqlite3_free(zUncompress);
+              zUncompress = zVal;
+              zVal = 0;
+              break;
+
+            case 4:               /* ORDER */
+              if( (strlen(zVal)!=3 || sqlite3_strnicmp(zVal, "asc", 3)) 
+               && (strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "desc", 4)) 
+              ){
+                *pzErr = sqlite3_mprintf("unrecognized order: %s", zVal);
+                rc = SQLITE_ERROR;
+              }
+              bDescIdx = (zVal[0]=='d' || zVal[0]=='D');
+              break;
+
+            case 5:              /* CONTENT */
+              sqlite3_free(zContent);
+              zContent = zVal;
+              zVal = 0;
+              break;
+
+            case 6:              /* LANGUAGEID */
+              assert( iOpt==6 );
+              sqlite3_free(zLanguageid);
+              zLanguageid = zVal;
+              zVal = 0;
+              break;
+          }
+        }
+        sqlite3_free(zVal);
+      }
+    }
+
+    /* Otherwise, the argument is a column name. */
+    else {
+      nString += (int)(strlen(z) + 1);
+      aCol[nCol++] = z;
+    }
+  }
+
+  /* If a content=xxx option was specified, the following:
+  **
+  **   1. Ignore any compress= and uncompress= options.
+  **
+  **   2. If no column names were specified as part of the CREATE VIRTUAL
+  **      TABLE statement, use all columns from the content table.
+  */
+  if( rc==SQLITE_OK && zContent ){
+    sqlite3_free(zCompress); 
+    sqlite3_free(zUncompress); 
+    zCompress = 0;
+    zUncompress = 0;
+    if( nCol==0 ){
+      sqlite3_free((void*)aCol); 
+      aCol = 0;
+      rc = fts3ContentColumns(db, argv[1], zContent, &aCol, &nCol, &nString);
+
+      /* If a languageid= option was specified, remove the language id
+      ** column from the aCol[] array. */ 
+      if( rc==SQLITE_OK && zLanguageid ){
+        int j;
+        for(j=0; j<nCol; j++){
+          if( sqlite3_stricmp(zLanguageid, aCol[j])==0 ){
+            int k;
+            for(k=j; k<nCol; k++) aCol[k] = aCol[k+1];
+            nCol--;
+            break;
+          }
+        }
+      }
+    }
+  }
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  if( nCol==0 ){
+    assert( nString==0 );
+    aCol[0] = "content";
+    nString = 8;
+    nCol = 1;
+  }
+
+  if( pTokenizer==0 ){
+    rc = sqlite3Fts3InitTokenizer(pHash, "simple", &pTokenizer, pzErr);
+    if( rc!=SQLITE_OK ) goto fts3_init_out;
+  }
+  assert( pTokenizer );
+
+  rc = fts3PrefixParameter(zPrefix, &nIndex, &aIndex);
+  if( rc==SQLITE_ERROR ){
+    assert( zPrefix );
+    *pzErr = sqlite3_mprintf("error parsing prefix parameter: %s", zPrefix);
+  }
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  /* Allocate and populate the Fts3Table structure. */
+  nByte = sizeof(Fts3Table) +                  /* Fts3Table */
+          nCol * sizeof(char *) +              /* azColumn */
+          nIndex * sizeof(struct Fts3Index) +  /* aIndex */
+          nName +                              /* zName */
+          nDb +                                /* zDb */
+          nString;                             /* Space for azColumn strings */
+  p = (Fts3Table*)sqlite3_malloc(nByte);
+  if( p==0 ){
+    rc = SQLITE_NOMEM;
+    goto fts3_init_out;
+  }
+  memset(p, 0, nByte);
+  p->db = db;
+  p->nColumn = nCol;
+  p->nPendingData = 0;
+  p->azColumn = (char **)&p[1];
+  p->pTokenizer = pTokenizer;
+  p->nMaxPendingData = FTS3_MAX_PENDING_DATA;
+  p->bHasDocsize = (isFts4 && bNoDocsize==0);
+  p->bHasStat = isFts4;
+  p->bFts4 = isFts4;
+  p->bDescIdx = bDescIdx;
+  p->bAutoincrmerge = 0xff;   /* 0xff means setting unknown */
+  p->zContentTbl = zContent;
+  p->zLanguageid = zLanguageid;
+  zContent = 0;
+  zLanguageid = 0;
+  TESTONLY( p->inTransaction = -1 );
+  TESTONLY( p->mxSavepoint = -1 );
+
+  p->aIndex = (struct Fts3Index *)&p->azColumn[nCol];
+  memcpy(p->aIndex, aIndex, sizeof(struct Fts3Index) * nIndex);
+  p->nIndex = nIndex;
+  for(i=0; i<nIndex; i++){
+    fts3HashInit(&p->aIndex[i].hPending, FTS3_HASH_STRING, 1);
+  }
+
+  /* Fill in the zName and zDb fields of the vtab structure. */
+  zCsr = (char *)&p->aIndex[nIndex];
+  p->zName = zCsr;
+  memcpy(zCsr, argv[2], nName);
+  zCsr += nName;
+  p->zDb = zCsr;
+  memcpy(zCsr, argv[1], nDb);
+  zCsr += nDb;
+
+  /* Fill in the azColumn array */
+  for(iCol=0; iCol<nCol; iCol++){
+    char *z; 
+    int n = 0;
+    z = (char *)sqlite3Fts3NextToken(aCol[iCol], &n);
+    memcpy(zCsr, z, n);
+    zCsr[n] = '\0';
+    sqlite3Fts3Dequote(zCsr);
+    p->azColumn[iCol] = zCsr;
+    zCsr += n+1;
+    assert( zCsr <= &((char *)p)[nByte] );
+  }
+
+  if( (zCompress==0)!=(zUncompress==0) ){
+    char const *zMiss = (zCompress==0 ? "compress" : "uncompress");
+    rc = SQLITE_ERROR;
+    *pzErr = sqlite3_mprintf("missing %s parameter in fts4 constructor", zMiss);
+  }
+  p->zReadExprlist = fts3ReadExprList(p, zUncompress, &rc);
+  p->zWriteExprlist = fts3WriteExprList(p, zCompress, &rc);
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  /* If this is an xCreate call, create the underlying tables in the 
+  ** database. TODO: For xConnect(), it could verify that said tables exist.
+  */
+  if( isCreate ){
+    rc = fts3CreateTables(p);
+  }
+
+  /* Check to see if a legacy fts3 table has been "upgraded" by the
+  ** addition of a %_stat table so that it can use incremental merge.
+  */
+  if( !isFts4 && !isCreate ){
+    int rc2 = SQLITE_OK;
+    fts3DbExec(&rc2, db, "SELECT 1 FROM %Q.'%q_stat' WHERE id=2",
+               p->zDb, p->zName);
+    if( rc2==SQLITE_OK ) p->bHasStat = 1;
+  }
+
+  /* Figure out the page-size for the database. This is required in order to
+  ** estimate the cost of loading large doclists from the database.  */
+  fts3DatabasePageSize(&rc, p);
+  p->nNodeSize = p->nPgsz-35;
+
+  /* Declare the table schema to SQLite. */
+  fts3DeclareVtab(&rc, p);
+
+fts3_init_out:
+  sqlite3_free(zPrefix);
+  sqlite3_free(aIndex);
+  sqlite3_free(zCompress);
+  sqlite3_free(zUncompress);
+  sqlite3_free(zContent);
+  sqlite3_free(zLanguageid);
+  sqlite3_free((void *)aCol);
+  if( rc!=SQLITE_OK ){
+    if( p ){
+      fts3DisconnectMethod((sqlite3_vtab *)p);
+    }else if( pTokenizer ){
+      pTokenizer->pModule->xDestroy(pTokenizer);
+    }
+  }else{
+    assert( p->pSegments==0 );
+    *ppVTab = &p->base;
+  }
+  return rc;
+}
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts3InitVtab().
+*/
+static int fts3ConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts3CreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/* 
+** Implementation of the xBestIndex method for FTS3 tables. There
+** are three possible strategies, in order of preference:
+**
+**   1. Direct lookup by rowid or docid. 
+**   2. Full-text search using a MATCH operator on a non-docid column.
+**   3. Linear scan of %_content table.
+*/
+static int fts3BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  Fts3Table *p = (Fts3Table *)pVTab;
+  int i;                          /* Iterator variable */
+  int iCons = -1;                 /* Index of constraint to use */
+  int iLangidCons = -1;           /* Index of langid=x constraint, if present */
+
+  /* By default use a full table scan. This is an expensive option,
+  ** so search through the constraints to see if a more efficient 
+  ** strategy is possible.
+  */
+  pInfo->idxNum = FTS3_FULLSCAN_SEARCH;
+  pInfo->estimatedCost = 500000;
+  for(i=0; i<pInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *pCons = &pInfo->aConstraint[i];
+    if( pCons->usable==0 ) continue;
+
+    /* A direct lookup on the rowid or docid column. Assign a cost of 1.0. */
+    if( iCons<0 
+     && pCons->op==SQLITE_INDEX_CONSTRAINT_EQ 
+     && (pCons->iColumn<0 || pCons->iColumn==p->nColumn+1 )
+    ){
+      pInfo->idxNum = FTS3_DOCID_SEARCH;
+      pInfo->estimatedCost = 1.0;
+      iCons = i;
+    }
+
+    /* A MATCH constraint. Use a full-text search.
+    **
+    ** If there is more than one MATCH constraint available, use the first
+    ** one encountered. If there is both a MATCH constraint and a direct
+    ** rowid/docid lookup, prefer the MATCH strategy. This is done even 
+    ** though the rowid/docid lookup is faster than a MATCH query, selecting
+    ** it would lead to an "unable to use function MATCH in the requested 
+    ** context" error.
+    */
+    if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH 
+     && pCons->iColumn>=0 && pCons->iColumn<=p->nColumn
+    ){
+      pInfo->idxNum = FTS3_FULLTEXT_SEARCH + pCons->iColumn;
+      pInfo->estimatedCost = 2.0;
+      iCons = i;
+    }
+
+    /* Equality constraint on the langid column */
+    if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ 
+     && pCons->iColumn==p->nColumn + 2
+    ){
+      iLangidCons = i;
+    }
+  }
+
+  if( iCons>=0 ){
+    pInfo->aConstraintUsage[iCons].argvIndex = 1;
+    pInfo->aConstraintUsage[iCons].omit = 1;
+  } 
+  if( iLangidCons>=0 ){
+    pInfo->aConstraintUsage[iLangidCons].argvIndex = 2;
+  } 
+
+  /* Regardless of the strategy selected, FTS can deliver rows in rowid (or
+  ** docid) order. Both ascending and descending are possible. 
+  */
+  if( pInfo->nOrderBy==1 ){
+    struct sqlite3_index_orderby *pOrder = &pInfo->aOrderBy[0];
+    if( pOrder->iColumn<0 || pOrder->iColumn==p->nColumn+1 ){
+      if( pOrder->desc ){
+        pInfo->idxStr = "DESC";
+      }else{
+        pInfo->idxStr = "ASC";
+      }
+      pInfo->orderByConsumed = 1;
+    }
+  }
+
+  assert( p->pSegments==0 );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  sqlite3_vtab_cursor *pCsr;               /* Allocated cursor */
+
+  UNUSED_PARAMETER(pVTab);
+
+  /* Allocate a buffer large enough for an Fts3Cursor structure. If the
+  ** allocation succeeds, zero it and return SQLITE_OK. Otherwise, 
+  ** if the allocation fails, return SQLITE_NOMEM.
+  */
+  *ppCsr = pCsr = (sqlite3_vtab_cursor *)sqlite3_malloc(sizeof(Fts3Cursor));
+  if( !pCsr ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(Fts3Cursor));
+  return SQLITE_OK;
+}
 
 /*
 ** Close the cursor.  For additional information see the documentation
 ** on the xClose method of the virtual table interface.
 */
-static int fulltextClose(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  FTSTRACE(("FTS3 Close %p\n", c));
-  sqlite3_finalize(c->pStmt);
-  sqlite3Fts3ExprFree(c->pExpr);
-  snippetClear(&c->snippet);
-  if( c->result.nData!=0 ){
-    dlrDestroy(&c->reader);
-  }
-  dataBufferDestroy(&c->result);
-  sqlite3_free(c);
+static int fts3CloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3Fts3ExprFree(pCsr->pExpr);
+  sqlite3Fts3FreeDeferredTokens(pCsr);
+  sqlite3_free(pCsr->aDoclist);
+  sqlite3_free(pCsr->aMatchinfo);
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  sqlite3_free(pCsr);
   return SQLITE_OK;
 }
 
-static int fulltextNext(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  int rc;
-
-  FTSTRACE(("FTS3 Next %p\n", pCursor));
-  snippetClear(&c->snippet);
-  if( c->iCursorType < QUERY_FULLTEXT ){
-    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
-    rc = sqlite3_step(c->pStmt);
-    switch( rc ){
-      case SQLITE_ROW:
-        c->eof = 0;
-        return SQLITE_OK;
-      case SQLITE_DONE:
-        c->eof = 1;
-        return SQLITE_OK;
-      default:
-        c->eof = 1;
-        return rc;
-    }
-  } else {  /* full-text query */
-    rc = sqlite3_reset(c->pStmt);
-    if( rc!=SQLITE_OK ) return rc;
-
-    if( c->result.nData==0 || dlrAtEnd(&c->reader) ){
-      c->eof = 1;
-      return SQLITE_OK;
-    }
-    rc = sqlite3_bind_int64(c->pStmt, 1, dlrDocid(&c->reader));
-    dlrStep(&c->reader);
-    if( rc!=SQLITE_OK ) return rc;
-    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
-    rc = sqlite3_step(c->pStmt);
-    if( rc==SQLITE_ROW ){   /* the case we expect */
-      c->eof = 0;
-      return SQLITE_OK;
-    }
-    /* an error occurred; abort */
-    return rc==SQLITE_DONE ? SQLITE_ERROR : rc;
+/*
+** If pCsr->pStmt has not been prepared (i.e. if pCsr->pStmt==0), then
+** compose and prepare an SQL statement of the form:
+**
+**    "SELECT <columns> FROM %_content WHERE rowid = ?"
+**
+** (or the equivalent for a content=xxx table) and set pCsr->pStmt to
+** it. If an error occurs, return an SQLite error code.
+**
+** Otherwise, set *ppStmt to point to pCsr->pStmt and return SQLITE_OK.
+*/
+static int fts3CursorSeekStmt(Fts3Cursor *pCsr, sqlite3_stmt **ppStmt){
+  int rc = SQLITE_OK;
+  if( pCsr->pStmt==0 ){
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    char *zSql;
+    zSql = sqlite3_mprintf("SELECT %s WHERE rowid = ?", p->zReadExprlist);
+    if( !zSql ) return SQLITE_NOMEM;
+    rc = sqlite3_prepare_v2(p->db, zSql, -1, &pCsr->pStmt, 0);
+    sqlite3_free(zSql);
   }
+  *ppStmt = pCsr->pStmt;
+  return rc;
+}
+
+/*
+** Position the pCsr->pStmt statement so that it is on the row
+** of the %_content table that contains the last match.  Return
+** SQLITE_OK on success.  
+*/
+static int fts3CursorSeek(sqlite3_context *pContext, Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;
+  if( pCsr->isRequireSeek ){
+    sqlite3_stmt *pStmt = 0;
+
+    rc = fts3CursorSeekStmt(pCsr, &pStmt);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
+      pCsr->isRequireSeek = 0;
+      if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
+        return SQLITE_OK;
+      }else{
+        rc = sqlite3_reset(pCsr->pStmt);
+        if( rc==SQLITE_OK && ((Fts3Table *)pCsr->base.pVtab)->zContentTbl==0 ){
+          /* If no row was found and no error has occured, then the %_content
+          ** table is missing a row that is present in the full-text index.
+          ** The data structures are corrupt.  */
+          rc = FTS_CORRUPT_VTAB;
+          pCsr->isEof = 1;
+        }
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK && pContext ){
+    sqlite3_result_error_code(pContext, rc);
+  }
+  return rc;
+}
+
+/*
+** This function is used to process a single interior node when searching
+** a b-tree for a term or term prefix. The node data is passed to this 
+** function via the zNode/nNode parameters. The term to search for is
+** passed in zTerm/nTerm.
+**
+** If piFirst is not NULL, then this function sets *piFirst to the blockid
+** of the child node that heads the sub-tree that may contain the term.
+**
+** If piLast is not NULL, then *piLast is set to the right-most child node
+** that heads a sub-tree that may contain a term for which zTerm/nTerm is
+** a prefix.
+**
+** If an OOM error occurs, SQLITE_NOMEM is returned. Otherwise, SQLITE_OK.
+*/
+static int fts3ScanInteriorNode(
+  const char *zTerm,              /* Term to select leaves for */
+  int nTerm,                      /* Size of term zTerm in bytes */
+  const char *zNode,              /* Buffer containing segment interior node */
+  int nNode,                      /* Size of buffer at zNode */
+  sqlite3_int64 *piFirst,         /* OUT: Selected child node */
+  sqlite3_int64 *piLast           /* OUT: Selected child node */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  const char *zCsr = zNode;       /* Cursor to iterate through node */
+  const char *zEnd = &zCsr[nNode];/* End of interior node buffer */
+  char *zBuffer = 0;              /* Buffer to load terms into */
+  int nAlloc = 0;                 /* Size of allocated buffer */
+  int isFirstTerm = 1;            /* True when processing first term on page */
+  sqlite3_int64 iChild;           /* Block id of child node to descend to */
+
+  /* Skip over the 'height' varint that occurs at the start of every 
+  ** interior node. Then load the blockid of the left-child of the b-tree
+  ** node into variable iChild.  
+  **
+  ** Even if the data structure on disk is corrupted, this (reading two
+  ** varints from the buffer) does not risk an overread. If zNode is a
+  ** root node, then the buffer comes from a SELECT statement. SQLite does
+  ** not make this guarantee explicitly, but in practice there are always
+  ** either more than 20 bytes of allocated space following the nNode bytes of
+  ** contents, or two zero bytes. Or, if the node is read from the %_segments
+  ** table, then there are always 20 bytes of zeroed padding following the
+  ** nNode bytes of content (see sqlite3Fts3ReadBlock() for details).
+  */
+  zCsr += sqlite3Fts3GetVarint(zCsr, &iChild);
+  zCsr += sqlite3Fts3GetVarint(zCsr, &iChild);
+  if( zCsr>zEnd ){
+    return FTS_CORRUPT_VTAB;
+  }
+  
+  while( zCsr<zEnd && (piFirst || piLast) ){
+    int cmp;                      /* memcmp() result */
+    int nSuffix;                  /* Size of term suffix */
+    int nPrefix = 0;              /* Size of term prefix */
+    int nBuffer;                  /* Total term size */
+  
+    /* Load the next term on the node into zBuffer. Use realloc() to expand
+    ** the size of zBuffer if required.  */
+    if( !isFirstTerm ){
+      zCsr += sqlite3Fts3GetVarint32(zCsr, &nPrefix);
+    }
+    isFirstTerm = 0;
+    zCsr += sqlite3Fts3GetVarint32(zCsr, &nSuffix);
+    
+    if( nPrefix<0 || nSuffix<0 || &zCsr[nSuffix]>zEnd ){
+      rc = FTS_CORRUPT_VTAB;
+      goto finish_scan;
+    }
+    if( nPrefix+nSuffix>nAlloc ){
+      char *zNew;
+      nAlloc = (nPrefix+nSuffix) * 2;
+      zNew = (char *)sqlite3_realloc(zBuffer, nAlloc);
+      if( !zNew ){
+        rc = SQLITE_NOMEM;
+        goto finish_scan;
+      }
+      zBuffer = zNew;
+    }
+    assert( zBuffer );
+    memcpy(&zBuffer[nPrefix], zCsr, nSuffix);
+    nBuffer = nPrefix + nSuffix;
+    zCsr += nSuffix;
+
+    /* Compare the term we are searching for with the term just loaded from
+    ** the interior node. If the specified term is greater than or equal
+    ** to the term from the interior node, then all terms on the sub-tree 
+    ** headed by node iChild are smaller than zTerm. No need to search 
+    ** iChild.
+    **
+    ** If the interior node term is larger than the specified term, then
+    ** the tree headed by iChild may contain the specified term.
+    */
+    cmp = memcmp(zTerm, zBuffer, (nBuffer>nTerm ? nTerm : nBuffer));
+    if( piFirst && (cmp<0 || (cmp==0 && nBuffer>nTerm)) ){
+      *piFirst = iChild;
+      piFirst = 0;
+    }
+
+    if( piLast && cmp<0 ){
+      *piLast = iChild;
+      piLast = 0;
+    }
+
+    iChild++;
+  };
+
+  if( piFirst ) *piFirst = iChild;
+  if( piLast ) *piLast = iChild;
+
+ finish_scan:
+  sqlite3_free(zBuffer);
+  return rc;
 }
 
 
-/* TODO(shess) If we pushed LeafReader to the top of the file, or to
-** another file, term_select() could be pushed above
-** docListOfTerm().
-*/
-static int termSelect(fulltext_vtab *v, int iColumn,
-                      const char *pTerm, int nTerm, int isPrefix,
-                      DocListType iType, DataBuffer *out);
-
-/* 
-** Return a DocList corresponding to the phrase *pPhrase.
+/*
+** The buffer pointed to by argument zNode (size nNode bytes) contains an
+** interior node of a b-tree segment. The zTerm buffer (size nTerm bytes)
+** contains a term. This function searches the sub-tree headed by the zNode
+** node for the range of leaf nodes that may contain the specified term
+** or terms for which the specified term is a prefix.
 **
-** The resulting DL_DOCIDS doclist is stored in pResult, which is
-** overwritten.
-*/
-static int docListOfPhrase(
-  fulltext_vtab *pTab,   /* The full text index */
-  Fts3Phrase *pPhrase,   /* Phrase to return a doclist corresponding to */
-  DocListType eListType, /* Either DL_DOCIDS or DL_POSITIONS */
-  DataBuffer *pResult    /* Write the result here */
+** If piLeaf is not NULL, then *piLeaf is set to the blockid of the 
+** left-most leaf node in the tree that may contain the specified term.
+** If piLeaf2 is not NULL, then *piLeaf2 is set to the blockid of the
+** right-most leaf node that may contain a term for which the specified
+** term is a prefix.
+**
+** It is possible that the range of returned leaf nodes does not contain 
+** the specified term or any terms for which it is a prefix. However, if the 
+** segment does contain any such terms, they are stored within the identified
+** range. Because this function only inspects interior segment nodes (and
+** never loads leaf nodes into memory), it is not possible to be sure.
+**
+** If an error occurs, an error code other than SQLITE_OK is returned.
+*/ 
+static int fts3SelectLeaf(
+  Fts3Table *p,                   /* Virtual table handle */
+  const char *zTerm,              /* Term to select leaves for */
+  int nTerm,                      /* Size of term zTerm in bytes */
+  const char *zNode,              /* Buffer containing segment interior node */
+  int nNode,                      /* Size of buffer at zNode */
+  sqlite3_int64 *piLeaf,          /* Selected leaf node */
+  sqlite3_int64 *piLeaf2          /* Selected leaf node */
 ){
-  int ii;
-  int rc = SQLITE_OK;
-  int iCol = pPhrase->iColumn;
-  DocListType eType = eListType;
-  assert( eType==DL_POSITIONS || eType==DL_DOCIDS );
-  if( pPhrase->nToken>1 ){
-    eType = DL_POSITIONS;
-  }
+  int rc;                         /* Return code */
+  int iHeight;                    /* Height of this node in tree */
 
-  /* This code should never be called with buffered updates. */
-  assert( pTab->nPendingData<0 );
+  assert( piLeaf || piLeaf2 );
 
-  for(ii=0; rc==SQLITE_OK && ii<pPhrase->nToken; ii++){
-    DataBuffer tmp;
-    struct PhraseToken *p = &pPhrase->aToken[ii];
-    rc = termSelect(pTab, iCol, p->z, p->n, p->isPrefix, eType, &tmp);
-    if( rc==SQLITE_OK ){
-      if( ii==0 ){
-        *pResult = tmp;
-      }else{
-        DataBuffer res = *pResult;
-        dataBufferInit(pResult, 0);
-        if( ii==(pPhrase->nToken-1) ){
-          eType = eListType;
-        }
-        docListPhraseMerge(
-          res.pData, res.nData, tmp.pData, tmp.nData, 0, 0, eType, pResult
-        );
-        dataBufferDestroy(&res);
-        dataBufferDestroy(&tmp);
+  sqlite3Fts3GetVarint32(zNode, &iHeight);
+  rc = fts3ScanInteriorNode(zTerm, nTerm, zNode, nNode, piLeaf, piLeaf2);
+  assert( !piLeaf2 || !piLeaf || rc!=SQLITE_OK || (*piLeaf<=*piLeaf2) );
+
+  if( rc==SQLITE_OK && iHeight>1 ){
+    char *zBlob = 0;              /* Blob read from %_segments table */
+    int nBlob;                    /* Size of zBlob in bytes */
+
+    if( piLeaf && piLeaf2 && (*piLeaf!=*piLeaf2) ){
+      rc = sqlite3Fts3ReadBlock(p, *piLeaf, &zBlob, &nBlob, 0);
+      if( rc==SQLITE_OK ){
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, 0);
       }
+      sqlite3_free(zBlob);
+      piLeaf = 0;
+      zBlob = 0;
     }
+
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3ReadBlock(p, piLeaf?*piLeaf:*piLeaf2, &zBlob, &nBlob, 0);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, piLeaf2);
+    }
+    sqlite3_free(zBlob);
   }
 
   return rc;
 }
 
 /*
-** Evaluate the full-text expression pExpr against fts3 table pTab. Write
-** the results into pRes.
+** This function is used to create delta-encoded serialized lists of FTS3 
+** varints. Each call to this function appends a single varint to a list.
 */
-static int evalFts3Expr(
-  fulltext_vtab *pTab,           /* Fts3 Virtual table object */
-  Fts3Expr *pExpr,               /* Parsed fts3 expression */
-  DataBuffer *pRes               /* OUT: Write results of the expression here */
+static void fts3PutDeltaVarint(
+  char **pp,                      /* IN/OUT: Output pointer */
+  sqlite3_int64 *piPrev,          /* IN/OUT: Previous value written to list */
+  sqlite3_int64 iVal              /* Write this value to the list */
 ){
-  int rc = SQLITE_OK;
+  assert( iVal-*piPrev > 0 || (*piPrev==0 && iVal==0) );
+  *pp += sqlite3Fts3PutVarint(*pp, iVal-*piPrev);
+  *piPrev = iVal;
+}
 
-  /* Initialize the output buffer. If this is an empty query (pExpr==0), 
-  ** this is all that needs to be done. Empty queries produce empty 
-  ** result sets.
+/*
+** When this function is called, *ppPoslist is assumed to point to the 
+** start of a position-list. After it returns, *ppPoslist points to the
+** first byte after the position-list.
+**
+** A position list is list of positions (delta encoded) and columns for 
+** a single document record of a doclist.  So, in other words, this
+** routine advances *ppPoslist so that it points to the next docid in
+** the doclist, or to the first byte past the end of the doclist.
+**
+** If pp is not NULL, then the contents of the position list are copied
+** to *pp. *pp is set to point to the first byte past the last byte copied
+** before this function returns.
+*/
+static void fts3PoslistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+
+  /* The end of a position list is marked by a zero encoded as an FTS3 
+  ** varint. A single POS_END (0) byte. Except, if the 0 byte is preceded by
+  ** a byte with the 0x80 bit set, then it is not a varint 0, but the tail
+  ** of some other, multi-byte, value.
+  **
+  ** The following while-loop moves pEnd to point to the first byte that is not 
+  ** immediately preceded by a byte with the 0x80 bit set. Then increments
+  ** pEnd once more so that it points to the byte immediately following the
+  ** last byte in the position-list.
   */
-  dataBufferInit(pRes, 0);
+  while( *pEnd | c ){
+    c = *pEnd++ & 0x80;
+    testcase( c!=0 && (*pEnd)==0 );
+  }
+  pEnd++;  /* Advance past the POS_END terminator byte */
 
-  if( pExpr ){
-    if( pExpr->eType==FTSQUERY_PHRASE ){
-      DocListType eType = DL_DOCIDS;
-      if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
-        eType = DL_POSITIONS;
-      }
-      rc = docListOfPhrase(pTab, pExpr->pPhrase, eType, pRes);
-    }else{
-      DataBuffer lhs;
-      DataBuffer rhs;
+  if( pp ){
+    int n = (int)(pEnd - *ppPoslist);
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
 
-      dataBufferInit(&rhs, 0);
-      if( SQLITE_OK==(rc = evalFts3Expr(pTab, pExpr->pLeft, &lhs)) 
-       && SQLITE_OK==(rc = evalFts3Expr(pTab, pExpr->pRight, &rhs)) 
-      ){
-        switch( pExpr->eType ){
-          case FTSQUERY_NEAR: {
-            int nToken;
-            Fts3Expr *pLeft;
-            DocListType eType = DL_DOCIDS;
-            if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
-              eType = DL_POSITIONS;
-            }
-            pLeft = pExpr->pLeft;
-            while( pLeft->eType==FTSQUERY_NEAR ){ 
-              pLeft=pLeft->pRight;
-            }
-            assert( pExpr->pRight->eType==FTSQUERY_PHRASE );
-            assert( pLeft->eType==FTSQUERY_PHRASE );
-            nToken = pLeft->pPhrase->nToken + pExpr->pRight->pPhrase->nToken;
-            docListPhraseMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData, 
-                pExpr->nNear+1, nToken, eType, pRes
-            );
-            break;
-          }
-          case FTSQUERY_NOT: {
-            docListExceptMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData,pRes);
-            break;
-          }
-          case FTSQUERY_AND: {
-            docListAndMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData, pRes);
-            break;
-          }
-          case FTSQUERY_OR: {
-            docListOrMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData, pRes);
-            break;
-          }
+/*
+** When this function is called, *ppPoslist is assumed to point to the 
+** start of a column-list. After it returns, *ppPoslist points to the
+** to the terminator (POS_COLUMN or POS_END) byte of the column-list.
+**
+** A column-list is list of delta-encoded positions for a single column
+** within a single document within a doclist.
+**
+** The column-list is terminated either by a POS_COLUMN varint (1) or
+** a POS_END varint (0).  This routine leaves *ppPoslist pointing to
+** the POS_COLUMN or POS_END that terminates the column-list.
+**
+** If pp is not NULL, then the contents of the column-list are copied
+** to *pp. *pp is set to point to the first byte past the last byte copied
+** before this function returns.  The POS_COLUMN or POS_END terminator
+** is not copied into *pp.
+*/
+static void fts3ColumnlistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+
+  /* A column-list is terminated by either a 0x01 or 0x00 byte that is
+  ** not part of a multi-byte varint.
+  */
+  while( 0xFE & (*pEnd | c) ){
+    c = *pEnd++ & 0x80;
+    testcase( c!=0 && ((*pEnd)&0xfe)==0 );
+  }
+  if( pp ){
+    int n = (int)(pEnd - *ppPoslist);
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
+
+/*
+** Value used to signify the end of an position-list. This is safe because
+** it is not possible to have a document with 2^31 terms.
+*/
+#define POSITION_LIST_END 0x7fffffff
+
+/*
+** This function is used to help parse position-lists. When this function is
+** called, *pp may point to the start of the next varint in the position-list
+** being parsed, or it may point to 1 byte past the end of the position-list
+** (in which case **pp will be a terminator bytes POS_END (0) or
+** (1)).
+**
+** If *pp points past the end of the current position-list, set *pi to 
+** POSITION_LIST_END and return. Otherwise, read the next varint from *pp,
+** increment the current value of *pi by the value read, and set *pp to
+** point to the next value before returning.
+**
+** Before calling this routine *pi must be initialized to the value of
+** the previous position, or zero if we are reading the first position
+** in the position-list.  Because positions are delta-encoded, the value
+** of the previous position is needed in order to compute the value of
+** the next position.
+*/
+static void fts3ReadNextPos(
+  char **pp,                    /* IN/OUT: Pointer into position-list buffer */
+  sqlite3_int64 *pi             /* IN/OUT: Value read from position-list */
+){
+  if( (**pp)&0xFE ){
+    fts3GetDeltaVarint(pp, pi);
+    *pi -= 2;
+  }else{
+    *pi = POSITION_LIST_END;
+  }
+}
+
+/*
+** If parameter iCol is not 0, write an POS_COLUMN (1) byte followed by
+** the value of iCol encoded as a varint to *pp.   This will start a new
+** column list.
+**
+** Set *pp to point to the byte just after the last byte written before 
+** returning (do not modify it if iCol==0). Return the total number of bytes
+** written (0 if iCol==0).
+*/
+static int fts3PutColNumber(char **pp, int iCol){
+  int n = 0;                      /* Number of bytes written */
+  if( iCol ){
+    char *p = *pp;                /* Output pointer */
+    n = 1 + sqlite3Fts3PutVarint(&p[1], iCol);
+    *p = 0x01;
+    *pp = &p[n];
+  }
+  return n;
+}
+
+/*
+** Compute the union of two position lists.  The output written
+** into *pp contains all positions of both *pp1 and *pp2 in sorted
+** order and with any duplicates removed.  All pointers are
+** updated appropriately.   The caller is responsible for insuring
+** that there is enough space in *pp to hold the complete output.
+*/
+static void fts3PoslistMerge(
+  char **pp,                      /* Output buffer */
+  char **pp1,                     /* Left input list */
+  char **pp2                      /* Right input list */
+){
+  char *p = *pp;
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  while( *p1 || *p2 ){
+    int iCol1;         /* The current column index in pp1 */
+    int iCol2;         /* The current column index in pp2 */
+
+    if( *p1==POS_COLUMN ) sqlite3Fts3GetVarint32(&p1[1], &iCol1);
+    else if( *p1==POS_END ) iCol1 = POSITION_LIST_END;
+    else iCol1 = 0;
+
+    if( *p2==POS_COLUMN ) sqlite3Fts3GetVarint32(&p2[1], &iCol2);
+    else if( *p2==POS_END ) iCol2 = POSITION_LIST_END;
+    else iCol2 = 0;
+
+    if( iCol1==iCol2 ){
+      sqlite3_int64 i1 = 0;       /* Last position from pp1 */
+      sqlite3_int64 i2 = 0;       /* Last position from pp2 */
+      sqlite3_int64 iPrev = 0;
+      int n = fts3PutColNumber(&p, iCol1);
+      p1 += n;
+      p2 += n;
+
+      /* At this point, both p1 and p2 point to the start of column-lists
+      ** for the same column (the column with index iCol1 and iCol2).
+      ** A column-list is a list of non-negative delta-encoded varints, each 
+      ** incremented by 2 before being stored. Each list is terminated by a
+      ** POS_END (0) or POS_COLUMN (1). The following block merges the two lists
+      ** and writes the results to buffer p. p is left pointing to the byte
+      ** after the list written. No terminator (POS_END or POS_COLUMN) is
+      ** written to the output.
+      */
+      fts3GetDeltaVarint(&p1, &i1);
+      fts3GetDeltaVarint(&p2, &i2);
+      do {
+        fts3PutDeltaVarint(&p, &iPrev, (i1<i2) ? i1 : i2); 
+        iPrev -= 2;
+        if( i1==i2 ){
+          fts3ReadNextPos(&p1, &i1);
+          fts3ReadNextPos(&p2, &i2);
+        }else if( i1<i2 ){
+          fts3ReadNextPos(&p1, &i1);
+        }else{
+          fts3ReadNextPos(&p2, &i2);
         }
-      }
-      dataBufferDestroy(&lhs);
-      dataBufferDestroy(&rhs);
+      }while( i1!=POSITION_LIST_END || i2!=POSITION_LIST_END );
+    }else if( iCol1<iCol2 ){
+      p1 += fts3PutColNumber(&p, iCol1);
+      fts3ColumnlistCopy(&p, &p1);
+    }else{
+      p2 += fts3PutColNumber(&p, iCol2);
+      fts3ColumnlistCopy(&p, &p2);
     }
   }
 
+  *p++ = POS_END;
+  *pp = p;
+  *pp1 = p1 + 1;
+  *pp2 = p2 + 1;
+}
+
+/*
+** This function is used to merge two position lists into one. When it is
+** called, *pp1 and *pp2 must both point to position lists. A position-list is
+** the part of a doclist that follows each document id. For example, if a row
+** contains:
+**
+**     'a b c'|'x y z'|'a b b a'
+**
+** Then the position list for this row for token 'b' would consist of:
+**
+**     0x02 0x01 0x02 0x03 0x03 0x00
+**
+** When this function returns, both *pp1 and *pp2 are left pointing to the
+** byte following the 0x00 terminator of their respective position lists.
+**
+** If isSaveLeft is 0, an entry is added to the output position list for 
+** each position in *pp2 for which there exists one or more positions in
+** *pp1 so that (pos(*pp2)>pos(*pp1) && pos(*pp2)-pos(*pp1)<=nToken). i.e.
+** when the *pp1 token appears before the *pp2 token, but not more than nToken
+** slots before it.
+**
+** e.g. nToken==1 searches for adjacent positions.
+*/
+static int fts3PoslistPhraseMerge(
+  char **pp,                      /* IN/OUT: Preallocated output buffer */
+  int nToken,                     /* Maximum difference in token positions */
+  int isSaveLeft,                 /* Save the left position */
+  int isExact,                    /* If *pp1 is exactly nTokens before *pp2 */
+  char **pp1,                     /* IN/OUT: Left input list */
+  char **pp2                      /* IN/OUT: Right input list */
+){
+  char *p = *pp;
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+  int iCol1 = 0;
+  int iCol2 = 0;
+
+  /* Never set both isSaveLeft and isExact for the same invocation. */
+  assert( isSaveLeft==0 || isExact==0 );
+
+  assert( p!=0 && *p1!=0 && *p2!=0 );
+  if( *p1==POS_COLUMN ){ 
+    p1++;
+    p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
+  }
+  if( *p2==POS_COLUMN ){ 
+    p2++;
+    p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
+  }
+
+  while( 1 ){
+    if( iCol1==iCol2 ){
+      char *pSave = p;
+      sqlite3_int64 iPrev = 0;
+      sqlite3_int64 iPos1 = 0;
+      sqlite3_int64 iPos2 = 0;
+
+      if( iCol1 ){
+        *p++ = POS_COLUMN;
+        p += sqlite3Fts3PutVarint(p, iCol1);
+      }
+
+      assert( *p1!=POS_END && *p1!=POS_COLUMN );
+      assert( *p2!=POS_END && *p2!=POS_COLUMN );
+      fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+      fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+
+      while( 1 ){
+        if( iPos2==iPos1+nToken 
+         || (isExact==0 && iPos2>iPos1 && iPos2<=iPos1+nToken) 
+        ){
+          sqlite3_int64 iSave;
+          iSave = isSaveLeft ? iPos1 : iPos2;
+          fts3PutDeltaVarint(&p, &iPrev, iSave+2); iPrev -= 2;
+          pSave = 0;
+          assert( p );
+        }
+        if( (!isSaveLeft && iPos2<=(iPos1+nToken)) || iPos2<=iPos1 ){
+          if( (*p2&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+        }else{
+          if( (*p1&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+        }
+      }
+
+      if( pSave ){
+        assert( pp && p );
+        p = pSave;
+      }
+
+      fts3ColumnlistCopy(0, &p1);
+      fts3ColumnlistCopy(0, &p2);
+      assert( (*p1&0xFE)==0 && (*p2&0xFE)==0 );
+      if( 0==*p1 || 0==*p2 ) break;
+
+      p1++;
+      p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
+      p2++;
+      p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
+    }
+
+    /* Advance pointer p1 or p2 (whichever corresponds to the smaller of
+    ** iCol1 and iCol2) so that it points to either the 0x00 that marks the
+    ** end of the position list, or the 0x01 that precedes the next 
+    ** column-number in the position list. 
+    */
+    else if( iCol1<iCol2 ){
+      fts3ColumnlistCopy(0, &p1);
+      if( 0==*p1 ) break;
+      p1++;
+      p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
+    }else{
+      fts3ColumnlistCopy(0, &p2);
+      if( 0==*p2 ) break;
+      p2++;
+      p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
+    }
+  }
+
+  fts3PoslistCopy(0, &p2);
+  fts3PoslistCopy(0, &p1);
+  *pp1 = p1;
+  *pp2 = p2;
+  if( *pp==p ){
+    return 0;
+  }
+  *p++ = 0x00;
+  *pp = p;
+  return 1;
+}
+
+/*
+** Merge two position-lists as required by the NEAR operator. The argument
+** position lists correspond to the left and right phrases of an expression 
+** like:
+**
+**     "phrase 1" NEAR "phrase number 2"
+**
+** Position list *pp1 corresponds to the left-hand side of the NEAR 
+** expression and *pp2 to the right. As usual, the indexes in the position 
+** lists are the offsets of the last token in each phrase (tokens "1" and "2" 
+** in the example above).
+**
+** The output position list - written to *pp - is a copy of *pp2 with those
+** entries that are not sufficiently NEAR entries in *pp1 removed.
+*/
+static int fts3PoslistNearMerge(
+  char **pp,                      /* Output buffer */
+  char *aTmp,                     /* Temporary buffer space */
+  int nRight,                     /* Maximum difference in token positions */
+  int nLeft,                      /* Maximum difference in token positions */
+  char **pp1,                     /* IN/OUT: Left input list */
+  char **pp2                      /* IN/OUT: Right input list */
+){
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  char *pTmp1 = aTmp;
+  char *pTmp2;
+  char *aTmp2;
+  int res = 1;
+
+  fts3PoslistPhraseMerge(&pTmp1, nRight, 0, 0, pp1, pp2);
+  aTmp2 = pTmp2 = pTmp1;
+  *pp1 = p1;
+  *pp2 = p2;
+  fts3PoslistPhraseMerge(&pTmp2, nLeft, 1, 0, pp2, pp1);
+  if( pTmp1!=aTmp && pTmp2!=aTmp2 ){
+    fts3PoslistMerge(pp, &aTmp, &aTmp2);
+  }else if( pTmp1!=aTmp ){
+    fts3PoslistCopy(pp, &aTmp);
+  }else if( pTmp2!=aTmp2 ){
+    fts3PoslistCopy(pp, &aTmp2);
+  }else{
+    res = 0;
+  }
+
+  return res;
+}
+
+/* 
+** An instance of this function is used to merge together the (potentially
+** large number of) doclists for each term that matches a prefix query.
+** See function fts3TermSelectMerge() for details.
+*/
+typedef struct TermSelect TermSelect;
+struct TermSelect {
+  char *aaOutput[16];             /* Malloc'd output buffers */
+  int anOutput[16];               /* Size each output buffer in bytes */
+};
+
+/*
+** This function is used to read a single varint from a buffer. Parameter
+** pEnd points 1 byte past the end of the buffer. When this function is
+** called, if *pp points to pEnd or greater, then the end of the buffer
+** has been reached. In this case *pp is set to 0 and the function returns.
+**
+** If *pp does not point to or past pEnd, then a single varint is read
+** from *pp. *pp is then set to point 1 byte past the end of the read varint.
+**
+** If bDescIdx is false, the value read is added to *pVal before returning.
+** If it is true, the value read is subtracted from *pVal before this 
+** function returns.
+*/
+static void fts3GetDeltaVarint3(
+  char **pp,                      /* IN/OUT: Point to read varint from */
+  char *pEnd,                     /* End of buffer */
+  int bDescIdx,                   /* True if docids are descending */
+  sqlite3_int64 *pVal             /* IN/OUT: Integer value */
+){
+  if( *pp>=pEnd ){
+    *pp = 0;
+  }else{
+    sqlite3_int64 iVal;
+    *pp += sqlite3Fts3GetVarint(*pp, &iVal);
+    if( bDescIdx ){
+      *pVal -= iVal;
+    }else{
+      *pVal += iVal;
+    }
+  }
+}
+
+/*
+** This function is used to write a single varint to a buffer. The varint
+** is written to *pp. Before returning, *pp is set to point 1 byte past the
+** end of the value written.
+**
+** If *pbFirst is zero when this function is called, the value written to
+** the buffer is that of parameter iVal. 
+**
+** If *pbFirst is non-zero when this function is called, then the value 
+** written is either (iVal-*piPrev) (if bDescIdx is zero) or (*piPrev-iVal)
+** (if bDescIdx is non-zero).
+**
+** Before returning, this function always sets *pbFirst to 1 and *piPrev
+** to the value of parameter iVal.
+*/
+static void fts3PutDeltaVarint3(
+  char **pp,                      /* IN/OUT: Output pointer */
+  int bDescIdx,                   /* True for descending docids */
+  sqlite3_int64 *piPrev,          /* IN/OUT: Previous value written to list */
+  int *pbFirst,                   /* IN/OUT: True after first int written */
+  sqlite3_int64 iVal              /* Write this value to the list */
+){
+  sqlite3_int64 iWrite;
+  if( bDescIdx==0 || *pbFirst==0 ){
+    iWrite = iVal - *piPrev;
+  }else{
+    iWrite = *piPrev - iVal;
+  }
+  assert( *pbFirst || *piPrev==0 );
+  assert( *pbFirst==0 || iWrite>0 );
+  *pp += sqlite3Fts3PutVarint(*pp, iWrite);
+  *piPrev = iVal;
+  *pbFirst = 1;
+}
+
+
+/*
+** This macro is used by various functions that merge doclists. The two
+** arguments are 64-bit docid values. If the value of the stack variable
+** bDescDoclist is 0 when this macro is invoked, then it returns (i1-i2). 
+** Otherwise, (i2-i1).
+**
+** Using this makes it easier to write code that can merge doclists that are
+** sorted in either ascending or descending order.
+*/
+#define DOCID_CMP(i1, i2) ((bDescDoclist?-1:1) * (i1-i2))
+
+/*
+** This function does an "OR" merge of two doclists (output contains all
+** positions contained in either argument doclist). If the docids in the 
+** input doclists are sorted in ascending order, parameter bDescDoclist
+** should be false. If they are sorted in ascending order, it should be
+** passed a non-zero value.
+**
+** If no error occurs, *paOut is set to point at an sqlite3_malloc'd buffer
+** containing the output doclist and SQLITE_OK is returned. In this case
+** *pnOut is set to the number of bytes in the output doclist.
+**
+** If an error occurs, an SQLite error code is returned. The output values
+** are undefined in this case.
+*/
+static int fts3DoclistOrMerge(
+  int bDescDoclist,               /* True if arguments are desc */
+  char *a1, int n1,               /* First doclist */
+  char *a2, int n2,               /* Second doclist */
+  char **paOut, int *pnOut        /* OUT: Malloc'd doclist */
+){
+  sqlite3_int64 i1 = 0;
+  sqlite3_int64 i2 = 0;
+  sqlite3_int64 iPrev = 0;
+  char *pEnd1 = &a1[n1];
+  char *pEnd2 = &a2[n2];
+  char *p1 = a1;
+  char *p2 = a2;
+  char *p;
+  char *aOut;
+  int bFirstOut = 0;
+
+  *paOut = 0;
+  *pnOut = 0;
+
+  /* Allocate space for the output. Both the input and output doclists
+  ** are delta encoded. If they are in ascending order (bDescDoclist==0),
+  ** then the first docid in each list is simply encoded as a varint. For
+  ** each subsequent docid, the varint stored is the difference between the
+  ** current and previous docid (a positive number - since the list is in
+  ** ascending order).
+  **
+  ** The first docid written to the output is therefore encoded using the 
+  ** same number of bytes as it is in whichever of the input lists it is
+  ** read from. And each subsequent docid read from the same input list 
+  ** consumes either the same or less bytes as it did in the input (since
+  ** the difference between it and the previous value in the output must
+  ** be a positive value less than or equal to the delta value read from 
+  ** the input list). The same argument applies to all but the first docid
+  ** read from the 'other' list. And to the contents of all position lists
+  ** that will be copied and merged from the input to the output.
+  **
+  ** However, if the first docid copied to the output is a negative number,
+  ** then the encoding of the first docid from the 'other' input list may
+  ** be larger in the output than it was in the input (since the delta value
+  ** may be a larger positive integer than the actual docid).
+  **
+  ** The space required to store the output is therefore the sum of the
+  ** sizes of the two inputs, plus enough space for exactly one of the input
+  ** docids to grow. 
+  **
+  ** A symetric argument may be made if the doclists are in descending 
+  ** order.
+  */
+  aOut = sqlite3_malloc(n1+n2+FTS3_VARINT_MAX-1);
+  if( !aOut ) return SQLITE_NOMEM;
+
+  p = aOut;
+  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
+  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
+  while( p1 || p2 ){
+    sqlite3_int64 iDiff = DOCID_CMP(i1, i2);
+
+    if( p2 && p1 && iDiff==0 ){
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      fts3PoslistMerge(&p, &p1, &p2);
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }else if( !p2 || (p1 && iDiff<0) ){
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      fts3PoslistCopy(&p, &p1);
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+    }else{
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i2);
+      fts3PoslistCopy(&p, &p2);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }
+  }
+
+  *paOut = aOut;
+  *pnOut = (int)(p-aOut);
+  assert( *pnOut<=n1+n2+FTS3_VARINT_MAX-1 );
+  return SQLITE_OK;
+}
+
+/*
+** This function does a "phrase" merge of two doclists. In a phrase merge,
+** the output contains a copy of each position from the right-hand input
+** doclist for which there is a position in the left-hand input doclist
+** exactly nDist tokens before it.
+**
+** If the docids in the input doclists are sorted in ascending order,
+** parameter bDescDoclist should be false. If they are sorted in ascending 
+** order, it should be passed a non-zero value.
+**
+** The right-hand input doclist is overwritten by this function.
+*/
+static void fts3DoclistPhraseMerge(
+  int bDescDoclist,               /* True if arguments are desc */
+  int nDist,                      /* Distance from left to right (1=adjacent) */
+  char *aLeft, int nLeft,         /* Left doclist */
+  char *aRight, int *pnRight      /* IN/OUT: Right/output doclist */
+){
+  sqlite3_int64 i1 = 0;
+  sqlite3_int64 i2 = 0;
+  sqlite3_int64 iPrev = 0;
+  char *pEnd1 = &aLeft[nLeft];
+  char *pEnd2 = &aRight[*pnRight];
+  char *p1 = aLeft;
+  char *p2 = aRight;
+  char *p;
+  int bFirstOut = 0;
+  char *aOut = aRight;
+
+  assert( nDist>0 );
+
+  p = aOut;
+  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
+  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
+
+  while( p1 && p2 ){
+    sqlite3_int64 iDiff = DOCID_CMP(i1, i2);
+    if( iDiff==0 ){
+      char *pSave = p;
+      sqlite3_int64 iPrevSave = iPrev;
+      int bFirstOutSave = bFirstOut;
+
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      if( 0==fts3PoslistPhraseMerge(&p, nDist, 0, 1, &p1, &p2) ){
+        p = pSave;
+        iPrev = iPrevSave;
+        bFirstOut = bFirstOutSave;
+      }
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }else if( iDiff<0 ){
+      fts3PoslistCopy(0, &p1);
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+    }else{
+      fts3PoslistCopy(0, &p2);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }
+  }
+
+  *pnRight = (int)(p - aOut);
+}
+
+/*
+** Argument pList points to a position list nList bytes in size. This
+** function checks to see if the position list contains any entries for
+** a token in position 0 (of any column). If so, it writes argument iDelta
+** to the output buffer pOut, followed by a position list consisting only
+** of the entries from pList at position 0, and terminated by an 0x00 byte.
+** The value returned is the number of bytes written to pOut (if any).
+*/
+SQLITE_PRIVATE int sqlite3Fts3FirstFilter(
+  sqlite3_int64 iDelta,           /* Varint that may be written to pOut */
+  char *pList,                    /* Position list (no 0x00 term) */
+  int nList,                      /* Size of pList in bytes */
+  char *pOut                      /* Write output here */
+){
+  int nOut = 0;
+  int bWritten = 0;               /* True once iDelta has been written */
+  char *p = pList;
+  char *pEnd = &pList[nList];
+
+  if( *p!=0x01 ){
+    if( *p==0x02 ){
+      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
+      pOut[nOut++] = 0x02;
+      bWritten = 1;
+    }
+    fts3ColumnlistCopy(0, &p);
+  }
+
+  while( p<pEnd && *p==0x01 ){
+    sqlite3_int64 iCol;
+    p++;
+    p += sqlite3Fts3GetVarint(p, &iCol);
+    if( *p==0x02 ){
+      if( bWritten==0 ){
+        nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
+        bWritten = 1;
+      }
+      pOut[nOut++] = 0x01;
+      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iCol);
+      pOut[nOut++] = 0x02;
+    }
+    fts3ColumnlistCopy(0, &p);
+  }
+  if( bWritten ){
+    pOut[nOut++] = 0x00;
+  }
+
+  return nOut;
+}
+
+
+/*
+** Merge all doclists in the TermSelect.aaOutput[] array into a single
+** doclist stored in TermSelect.aaOutput[0]. If successful, delete all
+** other doclists (except the aaOutput[0] one) and return SQLITE_OK.
+**
+** If an OOM error occurs, return SQLITE_NOMEM. In this case it is
+** the responsibility of the caller to free any doclists left in the
+** TermSelect.aaOutput[] array.
+*/
+static int fts3TermSelectFinishMerge(Fts3Table *p, TermSelect *pTS){
+  char *aOut = 0;
+  int nOut = 0;
+  int i;
+
+  /* Loop through the doclists in the aaOutput[] array. Merge them all
+  ** into a single doclist.
+  */
+  for(i=0; i<SizeofArray(pTS->aaOutput); i++){
+    if( pTS->aaOutput[i] ){
+      if( !aOut ){
+        aOut = pTS->aaOutput[i];
+        nOut = pTS->anOutput[i];
+        pTS->aaOutput[i] = 0;
+      }else{
+        int nNew;
+        char *aNew;
+
+        int rc = fts3DoclistOrMerge(p->bDescIdx, 
+            pTS->aaOutput[i], pTS->anOutput[i], aOut, nOut, &aNew, &nNew
+        );
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(aOut);
+          return rc;
+        }
+
+        sqlite3_free(pTS->aaOutput[i]);
+        sqlite3_free(aOut);
+        pTS->aaOutput[i] = 0;
+        aOut = aNew;
+        nOut = nNew;
+      }
+    }
+  }
+
+  pTS->aaOutput[0] = aOut;
+  pTS->anOutput[0] = nOut;
+  return SQLITE_OK;
+}
+
+/*
+** Merge the doclist aDoclist/nDoclist into the TermSelect object passed
+** as the first argument. The merge is an "OR" merge (see function
+** fts3DoclistOrMerge() for details).
+**
+** This function is called with the doclist for each term that matches
+** a queried prefix. It merges all these doclists into one, the doclist
+** for the specified prefix. Since there can be a very large number of
+** doclists to merge, the merging is done pair-wise using the TermSelect
+** object.
+**
+** This function returns SQLITE_OK if the merge is successful, or an
+** SQLite error code (SQLITE_NOMEM) if an error occurs.
+*/
+static int fts3TermSelectMerge(
+  Fts3Table *p,                   /* FTS table handle */
+  TermSelect *pTS,                /* TermSelect object to merge into */
+  char *aDoclist,                 /* Pointer to doclist */
+  int nDoclist                    /* Size of aDoclist in bytes */
+){
+  if( pTS->aaOutput[0]==0 ){
+    /* If this is the first term selected, copy the doclist to the output
+    ** buffer using memcpy(). */
+    pTS->aaOutput[0] = sqlite3_malloc(nDoclist);
+    pTS->anOutput[0] = nDoclist;
+    if( pTS->aaOutput[0] ){
+      memcpy(pTS->aaOutput[0], aDoclist, nDoclist);
+    }else{
+      return SQLITE_NOMEM;
+    }
+  }else{
+    char *aMerge = aDoclist;
+    int nMerge = nDoclist;
+    int iOut;
+
+    for(iOut=0; iOut<SizeofArray(pTS->aaOutput); iOut++){
+      if( pTS->aaOutput[iOut]==0 ){
+        assert( iOut>0 );
+        pTS->aaOutput[iOut] = aMerge;
+        pTS->anOutput[iOut] = nMerge;
+        break;
+      }else{
+        char *aNew;
+        int nNew;
+
+        int rc = fts3DoclistOrMerge(p->bDescIdx, aMerge, nMerge, 
+            pTS->aaOutput[iOut], pTS->anOutput[iOut], &aNew, &nNew
+        );
+        if( rc!=SQLITE_OK ){
+          if( aMerge!=aDoclist ) sqlite3_free(aMerge);
+          return rc;
+        }
+
+        if( aMerge!=aDoclist ) sqlite3_free(aMerge);
+        sqlite3_free(pTS->aaOutput[iOut]);
+        pTS->aaOutput[iOut] = 0;
+  
+        aMerge = aNew;
+        nMerge = nNew;
+        if( (iOut+1)==SizeofArray(pTS->aaOutput) ){
+          pTS->aaOutput[iOut] = aMerge;
+          pTS->anOutput[iOut] = nMerge;
+        }
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Append SegReader object pNew to the end of the pCsr->apSegment[] array.
+*/
+static int fts3SegReaderCursorAppend(
+  Fts3MultiSegReader *pCsr, 
+  Fts3SegReader *pNew
+){
+  if( (pCsr->nSegment%16)==0 ){
+    Fts3SegReader **apNew;
+    int nByte = (pCsr->nSegment + 16)*sizeof(Fts3SegReader*);
+    apNew = (Fts3SegReader **)sqlite3_realloc(pCsr->apSegment, nByte);
+    if( !apNew ){
+      sqlite3Fts3SegReaderFree(pNew);
+      return SQLITE_NOMEM;
+    }
+    pCsr->apSegment = apNew;
+  }
+  pCsr->apSegment[pCsr->nSegment++] = pNew;
+  return SQLITE_OK;
+}
+
+/*
+** Add seg-reader objects to the Fts3MultiSegReader object passed as the
+** 8th argument.
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+static int fts3SegReaderCursor(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
+  int iLevel,                     /* Level of segments to scan */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  int isScan,                     /* True to scan from zTerm to EOF */
+  Fts3MultiSegReader *pCsr        /* Cursor object to populate */
+){
+  int rc = SQLITE_OK;             /* Error code */
+  sqlite3_stmt *pStmt = 0;        /* Statement to iterate through segments */
+  int rc2;                        /* Result of sqlite3_reset() */
+
+  /* If iLevel is less than 0 and this is not a scan, include a seg-reader 
+  ** for the pending-terms. If this is a scan, then this call must be being
+  ** made by an fts4aux module, not an FTS table. In this case calling
+  ** Fts3SegReaderPending might segfault, as the data structures used by 
+  ** fts4aux are not completely populated. So it's easiest to filter these
+  ** calls out here.  */
+  if( iLevel<0 && p->aIndex ){
+    Fts3SegReader *pSeg = 0;
+    rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix, &pSeg);
+    if( rc==SQLITE_OK && pSeg ){
+      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
+    }
+  }
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3AllSegdirs(p, iLangid, iIndex, iLevel, &pStmt);
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
+      Fts3SegReader *pSeg = 0;
+
+      /* Read the values returned by the SELECT into local variables. */
+      sqlite3_int64 iStartBlock = sqlite3_column_int64(pStmt, 1);
+      sqlite3_int64 iLeavesEndBlock = sqlite3_column_int64(pStmt, 2);
+      sqlite3_int64 iEndBlock = sqlite3_column_int64(pStmt, 3);
+      int nRoot = sqlite3_column_bytes(pStmt, 4);
+      char const *zRoot = sqlite3_column_blob(pStmt, 4);
+
+      /* If zTerm is not NULL, and this segment is not stored entirely on its
+      ** root node, the range of leaves scanned can be reduced. Do this. */
+      if( iStartBlock && zTerm ){
+        sqlite3_int64 *pi = (isPrefix ? &iLeavesEndBlock : 0);
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &iStartBlock, pi);
+        if( rc!=SQLITE_OK ) goto finished;
+        if( isPrefix==0 && isScan==0 ) iLeavesEndBlock = iStartBlock;
+      }
+ 
+      rc = sqlite3Fts3SegReaderNew(pCsr->nSegment+1, 
+          (isPrefix==0 && isScan==0),
+          iStartBlock, iLeavesEndBlock, 
+          iEndBlock, zRoot, nRoot, &pSeg
+      );
+      if( rc!=SQLITE_OK ) goto finished;
+      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
+    }
+  }
+
+ finished:
+  rc2 = sqlite3_reset(pStmt);
+  if( rc==SQLITE_DONE ) rc = rc2;
+
   return rc;
 }
 
-/* TODO(shess) Refactor the code to remove this forward decl. */
-static int flushPendingTerms(fulltext_vtab *v);
-
-/* Perform a full-text query using the search expression in
-** zInput[0..nInput-1].  Return a list of matching documents
-** in pResult.
-**
-** Queries must match column iColumn.  Or if iColumn>=nColumn
-** they are allowed to match against any column.
+/*
+** Set up a cursor object for iterating through a full-text index or a 
+** single level therein.
 */
-static int fulltextQuery(
-  fulltext_vtab *v,      /* The full text index */
-  int iColumn,           /* Match against this column by default */
-  const char *zInput,    /* The query string */
-  int nInput,            /* Number of bytes in zInput[] */
-  DataBuffer *pResult,   /* Write the result doclist here */
-  Fts3Expr **ppExpr        /* Put parsed query string here */
+SQLITE_PRIVATE int sqlite3Fts3SegReaderCursor(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language-id to search */
+  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
+  int iLevel,                     /* Level of segments to scan */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  int isScan,                     /* True to scan from zTerm to EOF */
+  Fts3MultiSegReader *pCsr       /* Cursor object to populate */
 ){
-  int rc;
-
-  /* TODO(shess) Instead of flushing pendingTerms, we could query for
-  ** the relevant term and merge the doclist into what we receive from
-  ** the database.  Wait and see if this is a common issue, first.
-  **
-  ** A good reason not to flush is to not generate update-related
-  ** error codes from here.
-  */
-
-  /* Flush any buffered updates before executing the query. */
-  rc = flushPendingTerms(v);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
-
-  /* Parse the query passed to the MATCH operator. */
-  rc = sqlite3Fts3ExprParse(v->pTokenizer, 
-      v->azColumn, v->nColumn, iColumn, zInput, nInput, ppExpr
+  assert( iIndex>=0 && iIndex<p->nIndex );
+  assert( iLevel==FTS3_SEGCURSOR_ALL
+      ||  iLevel==FTS3_SEGCURSOR_PENDING 
+      ||  iLevel>=0
   );
-  if( rc!=SQLITE_OK ){
-    assert( 0==(*ppExpr) );
-    return rc;
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( FTS3_SEGCURSOR_ALL<0 && FTS3_SEGCURSOR_PENDING<0 );
+  assert( isPrefix==0 || isScan==0 );
+
+  memset(pCsr, 0, sizeof(Fts3MultiSegReader));
+  return fts3SegReaderCursor(
+      p, iLangid, iIndex, iLevel, zTerm, nTerm, isPrefix, isScan, pCsr
+  );
+}
+
+/*
+** In addition to its current configuration, have the Fts3MultiSegReader
+** passed as the 4th argument also scan the doclist for term zTerm/nTerm.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3SegReaderCursorAddZero(
+  Fts3Table *p,                   /* FTS virtual table handle */
+  int iLangid,
+  const char *zTerm,              /* Term to scan doclist of */
+  int nTerm,                      /* Number of bytes in zTerm */
+  Fts3MultiSegReader *pCsr        /* Fts3MultiSegReader to modify */
+){
+  return fts3SegReaderCursor(p, 
+      iLangid, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0,pCsr
+  );
+}
+
+/*
+** Open an Fts3MultiSegReader to scan the doclist for term zTerm/nTerm. Or,
+** if isPrefix is true, to scan the doclist for all terms for which 
+** zTerm/nTerm is a prefix. If successful, return SQLITE_OK and write
+** a pointer to the new Fts3MultiSegReader to *ppSegcsr. Otherwise, return
+** an SQLite error code.
+**
+** It is the responsibility of the caller to free this object by eventually
+** passing it to fts3SegReaderCursorFree() 
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+** Output parameter *ppSegcsr is set to 0 if an error occurs.
+*/
+static int fts3TermSegReaderCursor(
+  Fts3Cursor *pCsr,               /* Virtual table cursor handle */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  Fts3MultiSegReader **ppSegcsr   /* OUT: Allocated seg-reader cursor */
+){
+  Fts3MultiSegReader *pSegcsr;    /* Object to allocate and return */
+  int rc = SQLITE_NOMEM;          /* Return code */
+
+  pSegcsr = sqlite3_malloc(sizeof(Fts3MultiSegReader));
+  if( pSegcsr ){
+    int i;
+    int bFound = 0;               /* True once an index has been found */
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+
+    if( isPrefix ){
+      for(i=1; bFound==0 && i<p->nIndex; i++){
+        if( p->aIndex[i].nPrefix==nTerm ){
+          bFound = 1;
+          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid, 
+              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0, pSegcsr
+          );
+          pSegcsr->bLookup = 1;
+        }
+      }
+
+      for(i=1; bFound==0 && i<p->nIndex; i++){
+        if( p->aIndex[i].nPrefix==nTerm+1 ){
+          bFound = 1;
+          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid, 
+              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 1, 0, pSegcsr
+          );
+          if( rc==SQLITE_OK ){
+            rc = fts3SegReaderCursorAddZero(
+                p, pCsr->iLangid, zTerm, nTerm, pSegcsr
+            );
+          }
+        }
+      }
+    }
+
+    if( bFound==0 ){
+      rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid, 
+          0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr
+      );
+      pSegcsr->bLookup = !isPrefix;
+    }
   }
 
-  return evalFts3Expr(v, *ppExpr, pResult);
+  *ppSegcsr = pSegcsr;
+  return rc;
+}
+
+/*
+** Free an Fts3MultiSegReader allocated by fts3TermSegReaderCursor().
+*/
+static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){
+  sqlite3Fts3SegReaderFinish(pSegcsr);
+  sqlite3_free(pSegcsr);
+}
+
+/*
+** This function retreives the doclist for the specified term (or term
+** prefix) from the database.
+*/
+static int fts3TermSelect(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3PhraseToken *pTok,          /* Token to query for */
+  int iColumn,                    /* Column to query (or -ve for all columns) */
+  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
+  char **ppOut                    /* OUT: Malloced result buffer */
+){
+  int rc;                         /* Return code */
+  Fts3MultiSegReader *pSegcsr;    /* Seg-reader cursor for this term */
+  TermSelect tsc;                 /* Object for pair-wise doclist merging */
+  Fts3SegFilter filter;           /* Segment term filter configuration */
+
+  pSegcsr = pTok->pSegcsr;
+  memset(&tsc, 0, sizeof(TermSelect));
+
+  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY | FTS3_SEGMENT_REQUIRE_POS
+        | (pTok->isPrefix ? FTS3_SEGMENT_PREFIX : 0)
+        | (pTok->bFirst ? FTS3_SEGMENT_FIRST : 0)
+        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
+  filter.iCol = iColumn;
+  filter.zTerm = pTok->z;
+  filter.nTerm = pTok->n;
+
+  rc = sqlite3Fts3SegReaderStart(p, pSegcsr, &filter);
+  while( SQLITE_OK==rc
+      && SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pSegcsr)) 
+  ){
+    rc = fts3TermSelectMerge(p, &tsc, pSegcsr->aDoclist, pSegcsr->nDoclist);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts3TermSelectFinishMerge(p, &tsc);
+  }
+  if( rc==SQLITE_OK ){
+    *ppOut = tsc.aaOutput[0];
+    *pnOut = tsc.anOutput[0];
+  }else{
+    int i;
+    for(i=0; i<SizeofArray(tsc.aaOutput); i++){
+      sqlite3_free(tsc.aaOutput[i]);
+    }
+  }
+
+  fts3SegReaderCursorFree(pSegcsr);
+  pTok->pSegcsr = 0;
+  return rc;
+}
+
+/*
+** This function counts the total number of docids in the doclist stored
+** in buffer aList[], size nList bytes.
+**
+** If the isPoslist argument is true, then it is assumed that the doclist
+** contains a position-list following each docid. Otherwise, it is assumed
+** that the doclist is simply a list of docids stored as delta encoded 
+** varints.
+*/
+static int fts3DoclistCountDocids(char *aList, int nList){
+  int nDoc = 0;                   /* Return value */
+  if( aList ){
+    char *aEnd = &aList[nList];   /* Pointer to one byte after EOF */
+    char *p = aList;              /* Cursor */
+    while( p<aEnd ){
+      nDoc++;
+      while( (*p++)&0x80 );     /* Skip docid varint */
+      fts3PoslistCopy(0, &p);   /* Skip over position list */
+    }
+  }
+
+  return nDoc;
+}
+
+/*
+** Advance the cursor to the next row in the %_content table that
+** matches the search criteria.  For a MATCH search, this will be
+** the next row that matches. For a full-table scan, this will be
+** simply the next row in the %_content table.  For a docid lookup,
+** this routine simply sets the EOF flag.
+**
+** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
+** even if we reach end-of-file.  The fts3EofMethod() will be called
+** subsequently to determine whether or not an EOF was hit.
+*/
+static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
+  int rc;
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+  if( pCsr->eSearch==FTS3_DOCID_SEARCH || pCsr->eSearch==FTS3_FULLSCAN_SEARCH ){
+    if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
+      pCsr->isEof = 1;
+      rc = sqlite3_reset(pCsr->pStmt);
+    }else{
+      pCsr->iPrevId = sqlite3_column_int64(pCsr->pStmt, 0);
+      rc = SQLITE_OK;
+    }
+  }else{
+    rc = fts3EvalNext((Fts3Cursor *)pCursor);
+  }
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  return rc;
 }
 
 /*
@@ -93633,3070 +118864,646 @@ static int fulltextQuery(
 ** the virtual table xFilter method documentation for additional
 ** information.
 **
-** If idxNum==QUERY_GENERIC then do a full table scan against
+** If idxNum==FTS3_FULLSCAN_SEARCH then do a full table scan against
 ** the %_content table.
 **
-** If idxNum==QUERY_DOCID then do a docid lookup for a single entry
+** If idxNum==FTS3_DOCID_SEARCH then do a docid lookup for a single entry
 ** in the %_content table.
 **
-** If idxNum>=QUERY_FULLTEXT then use the full text index.  The
+** If idxNum>=FTS3_FULLTEXT_SEARCH then use the full text index.  The
 ** column on the left-hand side of the MATCH operator is column
-** number idxNum-QUERY_FULLTEXT, 0 indexed.  argv[0] is the right-hand
+** number idxNum-FTS3_FULLTEXT_SEARCH, 0 indexed.  argv[0] is the right-hand
 ** side of the MATCH operator.
 */
-/* TODO(shess) Upgrade the cursor initialization and destruction to
-** account for fulltextFilter() being called multiple times on the
-** same cursor.  The current solution is very fragile.  Apply fix to
-** fts3 as appropriate.
-*/
-static int fulltextFilter(
-  sqlite3_vtab_cursor *pCursor,     /* The cursor used for this query */
-  int idxNum, const char *idxStr,   /* Which indexing scheme to use */
-  int argc, sqlite3_value **argv    /* Arguments for the indexing scheme */
+static int fts3FilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
 ){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  fulltext_vtab *v = cursor_vtab(c);
   int rc;
+  char *zSql;                     /* SQL statement used to access %_content */
+  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
 
-  FTSTRACE(("FTS3 Filter %p\n",pCursor));
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(nVal);
 
-  /* If the cursor has a statement that was not prepared according to
-  ** idxNum, clear it.  I believe all calls to fulltextFilter with a
-  ** given cursor will have the same idxNum , but in this case it's
-  ** easy to be safe.
-  */
-  if( c->pStmt && c->iCursorType!=idxNum ){
-    sqlite3_finalize(c->pStmt);
-    c->pStmt = NULL;
-  }
+  assert( idxNum>=0 && idxNum<=(FTS3_FULLTEXT_SEARCH+p->nColumn) );
+  assert( nVal==0 || nVal==1 || nVal==2 );
+  assert( (nVal==0)==(idxNum==FTS3_FULLSCAN_SEARCH) );
+  assert( p->pSegments==0 );
 
-  /* Get a fresh statement appropriate to idxNum. */
-  /* TODO(shess): Add a prepared-statement cache in the vt structure.
-  ** The cache must handle multiple open cursors.  Easier to cache the
-  ** statement variants at the vt to reduce malloc/realloc/free here.
-  ** Or we could have a StringBuffer variant which allowed stack
-  ** construction for small values.
-  */
-  if( !c->pStmt ){
-    StringBuffer sb;
-    initStringBuffer(&sb);
-    append(&sb, "SELECT docid, ");
-    appendList(&sb, v->nColumn, v->azContentColumn);
-    append(&sb, " FROM %_content");
-    if( idxNum!=QUERY_GENERIC ) append(&sb, " WHERE docid = ?");
-    rc = sql_prepare(v->db, v->zDb, v->zName, &c->pStmt,
-                     stringBufferData(&sb));
-    stringBufferDestroy(&sb);
-    if( rc!=SQLITE_OK ) return rc;
-    c->iCursorType = idxNum;
+  /* In case the cursor has been used before, clear it now. */
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3_free(pCsr->aDoclist);
+  sqlite3Fts3ExprFree(pCsr->pExpr);
+  memset(&pCursor[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));
+
+  if( idxStr ){
+    pCsr->bDesc = (idxStr[0]=='D');
   }else{
-    sqlite3_reset(c->pStmt);
-    assert( c->iCursorType==idxNum );
+    pCsr->bDesc = p->bDescIdx;
+  }
+  pCsr->eSearch = (i16)idxNum;
+
+  if( idxNum!=FTS3_DOCID_SEARCH && idxNum!=FTS3_FULLSCAN_SEARCH ){
+    int iCol = idxNum-FTS3_FULLTEXT_SEARCH;
+    const char *zQuery = (const char *)sqlite3_value_text(apVal[0]);
+
+    if( zQuery==0 && sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
+      return SQLITE_NOMEM;
+    }
+
+    pCsr->iLangid = 0;
+    if( nVal==2 ) pCsr->iLangid = sqlite3_value_int(apVal[1]);
+
+    rc = sqlite3Fts3ExprParse(p->pTokenizer, pCsr->iLangid,
+        p->azColumn, p->bFts4, p->nColumn, iCol, zQuery, -1, &pCsr->pExpr
+    );
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_ERROR ){
+        static const char *zErr = "malformed MATCH expression: [%s]";
+        p->base.zErrMsg = sqlite3_mprintf(zErr, zQuery);
+      }
+      return rc;
+    }
+
+    rc = sqlite3Fts3ReadLock(p);
+    if( rc!=SQLITE_OK ) return rc;
+
+    rc = fts3EvalStart(pCsr);
+
+    sqlite3Fts3SegmentsClose(p);
+    if( rc!=SQLITE_OK ) return rc;
+    pCsr->pNextId = pCsr->aDoclist;
+    pCsr->iPrevId = 0;
   }
 
-  switch( idxNum ){
-    case QUERY_GENERIC:
-      break;
-
-    case QUERY_DOCID:
-      rc = sqlite3_bind_int64(c->pStmt, 1, sqlite3_value_int64(argv[0]));
-      if( rc!=SQLITE_OK ) return rc;
-      break;
-
-    default:   /* full-text search */
-    {
-      int iCol = idxNum-QUERY_FULLTEXT;
-      const char *zQuery = (const char *)sqlite3_value_text(argv[0]);
-      assert( idxNum<=QUERY_FULLTEXT+v->nColumn);
-      assert( argc==1 );
-      if( c->result.nData!=0 ){
-        /* This case happens if the same cursor is used repeatedly. */
-        dlrDestroy(&c->reader);
-        dataBufferReset(&c->result);
-      }else{
-        dataBufferInit(&c->result, 0);
-      }
-      rc = fulltextQuery(v, iCol, zQuery, -1, &c->result, &c->pExpr);
-      if( rc!=SQLITE_OK ) return rc;
-      if( c->result.nData!=0 ){
-        dlrInit(&c->reader, DL_DOCIDS, c->result.pData, c->result.nData);
-      }
-      break;
+  /* Compile a SELECT statement for this cursor. For a full-table-scan, the
+  ** statement loops through all rows of the %_content table. For a
+  ** full-text query or docid lookup, the statement retrieves a single
+  ** row by docid.
+  */
+  if( idxNum==FTS3_FULLSCAN_SEARCH ){
+    zSql = sqlite3_mprintf(
+        "SELECT %s ORDER BY rowid %s",
+        p->zReadExprlist, (pCsr->bDesc ? "DESC" : "ASC")
+    );
+    if( zSql ){
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pCsr->pStmt, 0);
+      sqlite3_free(zSql);
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }else if( idxNum==FTS3_DOCID_SEARCH ){
+    rc = fts3CursorSeekStmt(pCsr, &pCsr->pStmt);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_bind_value(pCsr->pStmt, 1, apVal[0]);
     }
   }
+  if( rc!=SQLITE_OK ) return rc;
 
-  return fulltextNext(pCursor);
+  return fts3NextMethod(pCursor);
 }
 
-/* This is the xEof method of the virtual table.  The SQLite core
-** calls this routine to find out if it has reached the end of
-** a query's results set.
+/* 
+** This is the xEof method of the virtual table. SQLite calls this 
+** routine to find out if it has reached the end of a result set.
 */
-static int fulltextEof(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  return c->eof;
+static int fts3EofMethod(sqlite3_vtab_cursor *pCursor){
+  return ((Fts3Cursor *)pCursor)->isEof;
 }
 
-/* This is the xColumn method of the virtual table.  The SQLite
-** core calls this method during a query when it needs the value
-** of a column from the virtual table.  This method needs to use
-** one of the sqlite3_result_*() routines to store the requested
-** value back in the pContext.
-*/
-static int fulltextColumn(sqlite3_vtab_cursor *pCursor,
-                          sqlite3_context *pContext, int idxCol){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  fulltext_vtab *v = cursor_vtab(c);
-
-  if( idxCol<v->nColumn ){
-    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, idxCol+1);
-    sqlite3_result_value(pContext, pVal);
-  }else if( idxCol==v->nColumn ){
-    /* The extra column whose name is the same as the table.
-    ** Return a blob which is a pointer to the cursor
-    */
-    sqlite3_result_blob(pContext, &c, sizeof(c), SQLITE_TRANSIENT);
-  }else if( idxCol==v->nColumn+1 ){
-    /* The docid column, which is an alias for rowid. */
-    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, 0);
-    sqlite3_result_value(pContext, pVal);
-  }
-  return SQLITE_OK;
-}
-
-/* This is the xRowid method.  The SQLite core calls this routine to
-** retrieve the rowid for the current row of the result set.  fts3
-** exposes %_content.docid as the rowid for the virtual table.  The
+/* 
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. fts3
+** exposes %_content.docid as the rowid for the virtual table. The
 ** rowid should be written to *pRowid.
 */
-static int fulltextRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-
-  *pRowid = sqlite3_column_int64(c->pStmt, 0);
+static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
+  *pRowid = pCsr->iPrevId;
   return SQLITE_OK;
 }
 
-/* Add all terms in [zText] to pendingTerms table.  If [iColumn] > 0,
-** we also store positions and offsets in the hash table using that
-** column number.
-*/
-static int buildTerms(fulltext_vtab *v, sqlite_int64 iDocid,
-                      const char *zText, int iColumn){
-  sqlite3_tokenizer *pTokenizer = v->pTokenizer;
-  sqlite3_tokenizer_cursor *pCursor;
-  const char *pToken;
-  int nTokenBytes;
-  int iStartOffset, iEndOffset, iPosition;
-  int rc;
-
-  rc = pTokenizer->pModule->xOpen(pTokenizer, zText, -1, &pCursor);
-  if( rc!=SQLITE_OK ) return rc;
-
-  pCursor->pTokenizer = pTokenizer;
-  while( SQLITE_OK==(rc=pTokenizer->pModule->xNext(pCursor,
-                                                   &pToken, &nTokenBytes,
-                                                   &iStartOffset, &iEndOffset,
-                                                   &iPosition)) ){
-    DLCollector *p;
-    int nData;                   /* Size of doclist before our update. */
-
-    /* Positions can't be negative; we use -1 as a terminator
-     * internally.  Token can't be NULL or empty. */
-    if( iPosition<0 || pToken == NULL || nTokenBytes == 0 ){
-      rc = SQLITE_ERROR;
-      break;
-    }
-
-    p = fts3HashFind(&v->pendingTerms, pToken, nTokenBytes);
-    if( p==NULL ){
-      nData = 0;
-      p = dlcNew(iDocid, DL_DEFAULT);
-      fts3HashInsert(&v->pendingTerms, pToken, nTokenBytes, p);
-
-      /* Overhead for our hash table entry, the key, and the value. */
-      v->nPendingData += sizeof(struct fts3HashElem)+sizeof(*p)+nTokenBytes;
-    }else{
-      nData = p->b.nData;
-      if( p->dlw.iPrevDocid!=iDocid ) dlcNext(p, iDocid);
-    }
-    if( iColumn>=0 ){
-      dlcAddPos(p, iColumn, iPosition, iStartOffset, iEndOffset);
-    }
-
-    /* Accumulate data added by dlcNew or dlcNext, and dlcAddPos. */
-    v->nPendingData += p->b.nData-nData;
-  }
-
-  /* TODO(shess) Check return?  Should this be able to cause errors at
-  ** this point?  Actually, same question about sqlite3_finalize(),
-  ** though one could argue that failure there means that the data is
-  ** not durable.  *ponder*
-  */
-  pTokenizer->pModule->xClose(pCursor);
-  if( SQLITE_DONE == rc ) return SQLITE_OK;
-  return rc;
-}
-
-/* Add doclists for all terms in [pValues] to pendingTerms table. */
-static int insertTerms(fulltext_vtab *v, sqlite_int64 iDocid,
-                       sqlite3_value **pValues){
-  int i;
-  for(i = 0; i < v->nColumn ; ++i){
-    char *zText = (char*)sqlite3_value_text(pValues[i]);
-    int rc = buildTerms(v, iDocid, zText, i);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-  return SQLITE_OK;
-}
-
-/* Add empty doclists for all terms in the given row's content to
-** pendingTerms.
-*/
-static int deleteTerms(fulltext_vtab *v, sqlite_int64 iDocid){
-  const char **pValues;
-  int i, rc;
-
-  /* TODO(shess) Should we allow such tables at all? */
-  if( DL_DEFAULT==DL_DOCIDS ) return SQLITE_ERROR;
-
-  rc = content_select(v, iDocid, &pValues);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i = 0 ; i < v->nColumn; ++i) {
-    rc = buildTerms(v, iDocid, pValues[i], -1);
-    if( rc!=SQLITE_OK ) break;
-  }
-
-  freeStringArray(v->nColumn, pValues);
-  return SQLITE_OK;
-}
-
-/* TODO(shess) Refactor the code to remove this forward decl. */
-static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid);
-
-/* Insert a row into the %_content table; set *piDocid to be the ID of the
-** new row.  Add doclists for terms to pendingTerms.
-*/
-static int index_insert(fulltext_vtab *v, sqlite3_value *pRequestDocid,
-                        sqlite3_value **pValues, sqlite_int64 *piDocid){
-  int rc;
-
-  rc = content_insert(v, pRequestDocid, pValues);  /* execute an SQL INSERT */
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* docid column is an alias for rowid. */
-  *piDocid = sqlite3_last_insert_rowid(v->db);
-  rc = initPendingTerms(v, *piDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return insertTerms(v, *piDocid, pValues);
-}
-
-/* Delete a row from the %_content table; add empty doclists for terms
-** to pendingTerms.
-*/
-static int index_delete(fulltext_vtab *v, sqlite_int64 iRow){
-  int rc = initPendingTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = deleteTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return content_delete(v, iRow);  /* execute an SQL DELETE */
-}
-
-/* Update a row in the %_content table; add delete doclists to
-** pendingTerms for old terms not in the new data, add insert doclists
-** to pendingTerms for terms in the new data.
-*/
-static int index_update(fulltext_vtab *v, sqlite_int64 iRow,
-                        sqlite3_value **pValues){
-  int rc = initPendingTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Generate an empty doclist for each term that previously appeared in this
-   * row. */
-  rc = deleteTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = content_update(v, pValues, iRow);  /* execute an SQL UPDATE */
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Now add positions for terms which appear in the updated row. */
-  return insertTerms(v, iRow, pValues);
-}
-
-/*******************************************************************/
-/* InteriorWriter is used to collect terms and block references into
-** interior nodes in %_segments.  See commentary at top of file for
-** format.
-*/
-
-/* How large interior nodes can grow. */
-#define INTERIOR_MAX 2048
-
-/* Minimum number of terms per interior node (except the root). This
-** prevents large terms from making the tree too skinny - must be >0
-** so that the tree always makes progress.  Note that the min tree
-** fanout will be INTERIOR_MIN_TERMS+1.
-*/
-#define INTERIOR_MIN_TERMS 7
-#if INTERIOR_MIN_TERMS<1
-# error INTERIOR_MIN_TERMS must be greater than 0.
-#endif
-
-/* ROOT_MAX controls how much data is stored inline in the segment
-** directory.
-*/
-/* TODO(shess) Push ROOT_MAX down to whoever is writing things.  It's
-** only here so that interiorWriterRootInfo() and leafWriterRootInfo()
-** can both see it, but if the caller passed it in, we wouldn't even
-** need a define.
-*/
-#define ROOT_MAX 1024
-#if ROOT_MAX<VARINT_MAX*2
-# error ROOT_MAX must have enough space for a header.
-#endif
-
-/* InteriorBlock stores a linked-list of interior blocks while a lower
-** layer is being constructed.
-*/
-typedef struct InteriorBlock {
-  DataBuffer term;           /* Leftmost term in block's subtree. */
-  DataBuffer data;           /* Accumulated data for the block. */
-  struct InteriorBlock *next;
-} InteriorBlock;
-
-static InteriorBlock *interiorBlockNew(int iHeight, sqlite_int64 iChildBlock,
-                                       const char *pTerm, int nTerm){
-  InteriorBlock *block = sqlite3_malloc(sizeof(InteriorBlock));
-  char c[VARINT_MAX+VARINT_MAX];
-  int n;
-
-  if( block ){
-    memset(block, 0, sizeof(*block));
-    dataBufferInit(&block->term, 0);
-    dataBufferReplace(&block->term, pTerm, nTerm);
-
-    n = fts3PutVarint(c, iHeight);
-    n += fts3PutVarint(c+n, iChildBlock);
-    dataBufferInit(&block->data, INTERIOR_MAX);
-    dataBufferReplace(&block->data, c, n);
-  }
-  return block;
-}
-
-#ifndef NDEBUG
-/* Verify that the data is readable as an interior node. */
-static void interiorBlockValidate(InteriorBlock *pBlock){
-  const char *pData = pBlock->data.pData;
-  int nData = pBlock->data.nData;
-  int n, iDummy;
-  sqlite_int64 iBlockid;
-
-  assert( nData>0 );
-  assert( pData!=0 );
-  assert( pData+nData>pData );
-
-  /* Must lead with height of node as a varint(n), n>0 */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( n>0 );
-  assert( iDummy>0 );
-  assert( n<nData );
-  pData += n;
-  nData -= n;
-
-  /* Must contain iBlockid. */
-  n = fts3GetVarint(pData, &iBlockid);
-  assert( n>0 );
-  assert( n<=nData );
-  pData += n;
-  nData -= n;
-
-  /* Zero or more terms of positive length */
-  if( nData!=0 ){
-    /* First term is not delta-encoded. */
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>0 );
-    assert( n+iDummy>0);
-    assert( n+iDummy<=nData );
-    pData += n+iDummy;
-    nData -= n+iDummy;
-
-    /* Following terms delta-encoded. */
-    while( nData!=0 ){
-      /* Length of shared prefix. */
-      n = fts3GetVarint32(pData, &iDummy);
-      assert( n>0 );
-      assert( iDummy>=0 );
-      assert( n<nData );
-      pData += n;
-      nData -= n;
-
-      /* Length and data of distinct suffix. */
-      n = fts3GetVarint32(pData, &iDummy);
-      assert( n>0 );
-      assert( iDummy>0 );
-      assert( n+iDummy>0);
-      assert( n+iDummy<=nData );
-      pData += n+iDummy;
-      nData -= n+iDummy;
-    }
-  }
-}
-#define ASSERT_VALID_INTERIOR_BLOCK(x) interiorBlockValidate(x)
-#else
-#define ASSERT_VALID_INTERIOR_BLOCK(x) assert( 1 )
-#endif
-
-typedef struct InteriorWriter {
-  int iHeight;                   /* from 0 at leaves. */
-  InteriorBlock *first, *last;
-  struct InteriorWriter *parentWriter;
-
-  DataBuffer term;               /* Last term written to block "last". */
-  sqlite_int64 iOpeningChildBlock; /* First child block in block "last". */
-#ifndef NDEBUG
-  sqlite_int64 iLastChildBlock;  /* for consistency checks. */
-#endif
-} InteriorWriter;
-
-/* Initialize an interior node where pTerm[nTerm] marks the leftmost
-** term in the tree.  iChildBlock is the leftmost child block at the
-** next level down the tree.
-*/
-static void interiorWriterInit(int iHeight, const char *pTerm, int nTerm,
-                               sqlite_int64 iChildBlock,
-                               InteriorWriter *pWriter){
-  InteriorBlock *block;
-  assert( iHeight>0 );
-  CLEAR(pWriter);
-
-  pWriter->iHeight = iHeight;
-  pWriter->iOpeningChildBlock = iChildBlock;
-#ifndef NDEBUG
-  pWriter->iLastChildBlock = iChildBlock;
-#endif
-  block = interiorBlockNew(iHeight, iChildBlock, pTerm, nTerm);
-  pWriter->last = pWriter->first = block;
-  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
-  dataBufferInit(&pWriter->term, 0);
-}
-
-/* Append the child node rooted at iChildBlock to the interior node,
-** with pTerm[nTerm] as the leftmost term in iChildBlock's subtree.
-*/
-static void interiorWriterAppend(InteriorWriter *pWriter,
-                                 const char *pTerm, int nTerm,
-                                 sqlite_int64 iChildBlock){
-  char c[VARINT_MAX+VARINT_MAX];
-  int n, nPrefix = 0;
-
-  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
-
-  /* The first term written into an interior node is actually
-  ** associated with the second child added (the first child was added
-  ** in interiorWriterInit, or in the if clause at the bottom of this
-  ** function).  That term gets encoded straight up, with nPrefix left
-  ** at 0.
-  */
-  if( pWriter->term.nData==0 ){
-    n = fts3PutVarint(c, nTerm);
-  }else{
-    while( nPrefix<pWriter->term.nData &&
-           pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
-      nPrefix++;
-    }
-
-    n = fts3PutVarint(c, nPrefix);
-    n += fts3PutVarint(c+n, nTerm-nPrefix);
-  }
-
-#ifndef NDEBUG
-  pWriter->iLastChildBlock++;
-#endif
-  assert( pWriter->iLastChildBlock==iChildBlock );
-
-  /* Overflow to a new block if the new term makes the current block
-  ** too big, and the current block already has enough terms.
-  */
-  if( pWriter->last->data.nData+n+nTerm-nPrefix>INTERIOR_MAX &&
-      iChildBlock-pWriter->iOpeningChildBlock>INTERIOR_MIN_TERMS ){
-    pWriter->last->next = interiorBlockNew(pWriter->iHeight, iChildBlock,
-                                           pTerm, nTerm);
-    pWriter->last = pWriter->last->next;
-    pWriter->iOpeningChildBlock = iChildBlock;
-    dataBufferReset(&pWriter->term);
-  }else{
-    dataBufferAppend2(&pWriter->last->data, c, n,
-                      pTerm+nPrefix, nTerm-nPrefix);
-    dataBufferReplace(&pWriter->term, pTerm, nTerm);
-  }
-  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
-}
-
-/* Free the space used by pWriter, including the linked-list of
-** InteriorBlocks, and parentWriter, if present.
-*/
-static int interiorWriterDestroy(InteriorWriter *pWriter){
-  InteriorBlock *block = pWriter->first;
-
-  while( block!=NULL ){
-    InteriorBlock *b = block;
-    block = block->next;
-    dataBufferDestroy(&b->term);
-    dataBufferDestroy(&b->data);
-    sqlite3_free(b);
-  }
-  if( pWriter->parentWriter!=NULL ){
-    interiorWriterDestroy(pWriter->parentWriter);
-    sqlite3_free(pWriter->parentWriter);
-  }
-  dataBufferDestroy(&pWriter->term);
-  SCRAMBLE(pWriter);
-  return SQLITE_OK;
-}
-
-/* If pWriter can fit entirely in ROOT_MAX, return it as the root info
-** directly, leaving *piEndBlockid unchanged.  Otherwise, flush
-** pWriter to %_segments, building a new layer of interior nodes, and
-** recursively ask for their root into.
-*/
-static int interiorWriterRootInfo(fulltext_vtab *v, InteriorWriter *pWriter,
-                                  char **ppRootInfo, int *pnRootInfo,
-                                  sqlite_int64 *piEndBlockid){
-  InteriorBlock *block = pWriter->first;
-  sqlite_int64 iBlockid = 0;
-  int rc;
-
-  /* If we can fit the segment inline */
-  if( block==pWriter->last && block->data.nData<ROOT_MAX ){
-    *ppRootInfo = block->data.pData;
-    *pnRootInfo = block->data.nData;
-    return SQLITE_OK;
-  }
-
-  /* Flush the first block to %_segments, and create a new level of
-  ** interior node.
-  */
-  ASSERT_VALID_INTERIOR_BLOCK(block);
-  rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-  *piEndBlockid = iBlockid;
-
-  pWriter->parentWriter = sqlite3_malloc(sizeof(*pWriter->parentWriter));
-  interiorWriterInit(pWriter->iHeight+1,
-                     block->term.pData, block->term.nData,
-                     iBlockid, pWriter->parentWriter);
-
-  /* Flush additional blocks and append to the higher interior
-  ** node.
-  */
-  for(block=block->next; block!=NULL; block=block->next){
-    ASSERT_VALID_INTERIOR_BLOCK(block);
-    rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-    *piEndBlockid = iBlockid;
-
-    interiorWriterAppend(pWriter->parentWriter,
-                         block->term.pData, block->term.nData, iBlockid);
-  }
-
-  /* Parent node gets the chance to be the root. */
-  return interiorWriterRootInfo(v, pWriter->parentWriter,
-                                ppRootInfo, pnRootInfo, piEndBlockid);
-}
-
-/****************************************************************/
-/* InteriorReader is used to read off the data from an interior node
-** (see comment at top of file for the format).
-*/
-typedef struct InteriorReader {
-  const char *pData;
-  int nData;
-
-  DataBuffer term;          /* previous term, for decoding term delta. */
-
-  sqlite_int64 iBlockid;
-} InteriorReader;
-
-static void interiorReaderDestroy(InteriorReader *pReader){
-  dataBufferDestroy(&pReader->term);
-  SCRAMBLE(pReader);
-}
-
-/* TODO(shess) The assertions are great, but what if we're in NDEBUG
-** and the blob is empty or otherwise contains suspect data?
-*/
-static void interiorReaderInit(const char *pData, int nData,
-                               InteriorReader *pReader){
-  int n, nTerm;
-
-  /* Require at least the leading flag byte */
-  assert( nData>0 );
-  assert( pData[0]!='\0' );
-
-  CLEAR(pReader);
-
-  /* Decode the base blockid, and set the cursor to the first term. */
-  n = fts3GetVarint(pData+1, &pReader->iBlockid);
-  assert( 1+n<=nData );
-  pReader->pData = pData+1+n;
-  pReader->nData = nData-(1+n);
-
-  /* A single-child interior node (such as when a leaf node was too
-  ** large for the segment directory) won't have any terms.
-  ** Otherwise, decode the first term.
-  */
-  if( pReader->nData==0 ){
-    dataBufferInit(&pReader->term, 0);
-  }else{
-    n = fts3GetVarint32(pReader->pData, &nTerm);
-    dataBufferInit(&pReader->term, nTerm);
-    dataBufferReplace(&pReader->term, pReader->pData+n, nTerm);
-    assert( n+nTerm<=pReader->nData );
-    pReader->pData += n+nTerm;
-    pReader->nData -= n+nTerm;
-  }
-}
-
-static int interiorReaderAtEnd(InteriorReader *pReader){
-  return pReader->term.nData==0;
-}
-
-static sqlite_int64 interiorReaderCurrentBlockid(InteriorReader *pReader){
-  return pReader->iBlockid;
-}
-
-static int interiorReaderTermBytes(InteriorReader *pReader){
-  assert( !interiorReaderAtEnd(pReader) );
-  return pReader->term.nData;
-}
-static const char *interiorReaderTerm(InteriorReader *pReader){
-  assert( !interiorReaderAtEnd(pReader) );
-  return pReader->term.pData;
-}
-
-/* Step forward to the next term in the node. */
-static void interiorReaderStep(InteriorReader *pReader){
-  assert( !interiorReaderAtEnd(pReader) );
-
-  /* If the last term has been read, signal eof, else construct the
-  ** next term.
-  */
-  if( pReader->nData==0 ){
-    dataBufferReset(&pReader->term);
-  }else{
-    int n, nPrefix, nSuffix;
-
-    n = fts3GetVarint32(pReader->pData, &nPrefix);
-    n += fts3GetVarint32(pReader->pData+n, &nSuffix);
-
-    /* Truncate the current term and append suffix data. */
-    pReader->term.nData = nPrefix;
-    dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
-
-    assert( n+nSuffix<=pReader->nData );
-    pReader->pData += n+nSuffix;
-    pReader->nData -= n+nSuffix;
-  }
-  pReader->iBlockid++;
-}
-
-/* Compare the current term to pTerm[nTerm], returning strcmp-style
-** results.  If isPrefix, equality means equal through nTerm bytes.
-*/
-static int interiorReaderTermCmp(InteriorReader *pReader,
-                                 const char *pTerm, int nTerm, int isPrefix){
-  const char *pReaderTerm = interiorReaderTerm(pReader);
-  int nReaderTerm = interiorReaderTermBytes(pReader);
-  int c, n = nReaderTerm<nTerm ? nReaderTerm : nTerm;
-
-  if( n==0 ){
-    if( nReaderTerm>0 ) return -1;
-    if( nTerm>0 ) return 1;
-    return 0;
-  }
-
-  c = memcmp(pReaderTerm, pTerm, n);
-  if( c!=0 ) return c;
-  if( isPrefix && n==nTerm ) return 0;
-  return nReaderTerm - nTerm;
-}
-
-/****************************************************************/
-/* LeafWriter is used to collect terms and associated doclist data
-** into leaf blocks in %_segments (see top of file for format info).
-** Expected usage is:
+/* 
+** This is the xColumn method, called by SQLite to request a value from
+** the row that the supplied cursor currently points to.
 **
-** LeafWriter writer;
-** leafWriterInit(0, 0, &writer);
-** while( sorted_terms_left_to_process ){
-**   // data is doclist data for that term.
-**   rc = leafWriterStep(v, &writer, pTerm, nTerm, pData, nData);
-**   if( rc!=SQLITE_OK ) goto err;
-** }
-** rc = leafWriterFinalize(v, &writer);
-**err:
-** leafWriterDestroy(&writer);
-** return rc;
+** If:
 **
-** leafWriterStep() may write a collected leaf out to %_segments.
-** leafWriterFinalize() finishes writing any buffered data and stores
-** a root node in %_segdir.  leafWriterDestroy() frees all buffers and
-** InteriorWriters allocated as part of writing this segment.
-**
-** TODO(shess) Document leafWriterStepMerge().
+**   (iCol <  p->nColumn)   -> The value of the iCol'th user column.
+**   (iCol == p->nColumn)   -> Magic column with the same name as the table.
+**   (iCol == p->nColumn+1) -> Docid column
+**   (iCol == p->nColumn+2) -> Langid column
 */
-
-/* Put terms with data this big in their own block. */
-#define STANDALONE_MIN 1024
-
-/* Keep leaf blocks below this size. */
-#define LEAF_MAX 2048
-
-typedef struct LeafWriter {
-  int iLevel;
-  int idx;
-  sqlite_int64 iStartBlockid;     /* needed to create the root info */
-  sqlite_int64 iEndBlockid;       /* when we're done writing. */
-
-  DataBuffer term;                /* previous encoded term */
-  DataBuffer data;                /* encoding buffer */
-
-  /* bytes of first term in the current node which distinguishes that
-  ** term from the last term of the previous node.
-  */
-  int nTermDistinct;
-
-  InteriorWriter parentWriter;    /* if we overflow */
-  int has_parent;
-} LeafWriter;
-
-static void leafWriterInit(int iLevel, int idx, LeafWriter *pWriter){
-  CLEAR(pWriter);
-  pWriter->iLevel = iLevel;
-  pWriter->idx = idx;
-
-  dataBufferInit(&pWriter->term, 32);
-
-  /* Start out with a reasonably sized block, though it can grow. */
-  dataBufferInit(&pWriter->data, LEAF_MAX);
-}
-
-#ifndef NDEBUG
-/* Verify that the data is readable as a leaf node. */
-static void leafNodeValidate(const char *pData, int nData){
-  int n, iDummy;
-
-  if( nData==0 ) return;
-  assert( nData>0 );
-  assert( pData!=0 );
-  assert( pData+nData>pData );
-
-  /* Must lead with a varint(0) */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( iDummy==0 );
-  assert( n>0 );
-  assert( n<nData );
-  pData += n;
-  nData -= n;
-
-  /* Leading term length and data must fit in buffer. */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( n>0 );
-  assert( iDummy>0 );
-  assert( n+iDummy>0 );
-  assert( n+iDummy<nData );
-  pData += n+iDummy;
-  nData -= n+iDummy;
-
-  /* Leading term's doclist length and data must fit. */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( n>0 );
-  assert( iDummy>0 );
-  assert( n+iDummy>0 );
-  assert( n+iDummy<=nData );
-  ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
-  pData += n+iDummy;
-  nData -= n+iDummy;
-
-  /* Verify that trailing terms and doclists also are readable. */
-  while( nData!=0 ){
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>=0 );
-    assert( n<nData );
-    pData += n;
-    nData -= n;
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>0 );
-    assert( n+iDummy>0 );
-    assert( n+iDummy<nData );
-    pData += n+iDummy;
-    nData -= n+iDummy;
-
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>0 );
-    assert( n+iDummy>0 );
-    assert( n+iDummy<=nData );
-    ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
-    pData += n+iDummy;
-    nData -= n+iDummy;
-  }
-}
-#define ASSERT_VALID_LEAF_NODE(p, n) leafNodeValidate(p, n)
-#else
-#define ASSERT_VALID_LEAF_NODE(p, n) assert( 1 )
-#endif
-
-/* Flush the current leaf node to %_segments, and adding the resulting
-** blockid and the starting term to the interior node which will
-** contain it.
-*/
-static int leafWriterInternalFlush(fulltext_vtab *v, LeafWriter *pWriter,
-                                   int iData, int nData){
-  sqlite_int64 iBlockid = 0;
-  const char *pStartingTerm;
-  int nStartingTerm, rc, n;
-
-  /* Must have the leading varint(0) flag, plus at least some
-  ** valid-looking data.
-  */
-  assert( nData>2 );
-  assert( iData>=0 );
-  assert( iData+nData<=pWriter->data.nData );
-  ASSERT_VALID_LEAF_NODE(pWriter->data.pData+iData, nData);
-
-  rc = block_insert(v, pWriter->data.pData+iData, nData, &iBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-  assert( iBlockid!=0 );
-
-  /* Reconstruct the first term in the leaf for purposes of building
-  ** the interior node.
-  */
-  n = fts3GetVarint32(pWriter->data.pData+iData+1, &nStartingTerm);
-  pStartingTerm = pWriter->data.pData+iData+1+n;
-  assert( pWriter->data.nData>iData+1+n+nStartingTerm );
-  assert( pWriter->nTermDistinct>0 );
-  assert( pWriter->nTermDistinct<=nStartingTerm );
-  nStartingTerm = pWriter->nTermDistinct;
-
-  if( pWriter->has_parent ){
-    interiorWriterAppend(&pWriter->parentWriter,
-                         pStartingTerm, nStartingTerm, iBlockid);
-  }else{
-    interiorWriterInit(1, pStartingTerm, nStartingTerm, iBlockid,
-                       &pWriter->parentWriter);
-    pWriter->has_parent = 1;
-  }
-
-  /* Track the span of this segment's leaf nodes. */
-  if( pWriter->iEndBlockid==0 ){
-    pWriter->iEndBlockid = pWriter->iStartBlockid = iBlockid;
-  }else{
-    pWriter->iEndBlockid++;
-    assert( iBlockid==pWriter->iEndBlockid );
-  }
-
-  return SQLITE_OK;
-}
-static int leafWriterFlush(fulltext_vtab *v, LeafWriter *pWriter){
-  int rc = leafWriterInternalFlush(v, pWriter, 0, pWriter->data.nData);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Re-initialize the output buffer. */
-  dataBufferReset(&pWriter->data);
-
-  return SQLITE_OK;
-}
-
-/* Fetch the root info for the segment.  If the entire leaf fits
-** within ROOT_MAX, then it will be returned directly, otherwise it
-** will be flushed and the root info will be returned from the
-** interior node.  *piEndBlockid is set to the blockid of the last
-** interior or leaf node written to disk (0 if none are written at
-** all).
-*/
-static int leafWriterRootInfo(fulltext_vtab *v, LeafWriter *pWriter,
-                              char **ppRootInfo, int *pnRootInfo,
-                              sqlite_int64 *piEndBlockid){
-  /* we can fit the segment entirely inline */
-  if( !pWriter->has_parent && pWriter->data.nData<ROOT_MAX ){
-    *ppRootInfo = pWriter->data.pData;
-    *pnRootInfo = pWriter->data.nData;
-    *piEndBlockid = 0;
-    return SQLITE_OK;
-  }
-
-  /* Flush remaining leaf data. */
-  if( pWriter->data.nData>0 ){
-    int rc = leafWriterFlush(v, pWriter);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  /* We must have flushed a leaf at some point. */
-  assert( pWriter->has_parent );
-
-  /* Tenatively set the end leaf blockid as the end blockid.  If the
-  ** interior node can be returned inline, this will be the final
-  ** blockid, otherwise it will be overwritten by
-  ** interiorWriterRootInfo().
-  */
-  *piEndBlockid = pWriter->iEndBlockid;
-
-  return interiorWriterRootInfo(v, &pWriter->parentWriter,
-                                ppRootInfo, pnRootInfo, piEndBlockid);
-}
-
-/* Collect the rootInfo data and store it into the segment directory.
-** This has the effect of flushing the segment's leaf data to
-** %_segments, and also flushing any interior nodes to %_segments.
-*/
-static int leafWriterFinalize(fulltext_vtab *v, LeafWriter *pWriter){
-  sqlite_int64 iEndBlockid;
-  char *pRootInfo;
-  int rc, nRootInfo;
-
-  rc = leafWriterRootInfo(v, pWriter, &pRootInfo, &nRootInfo, &iEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Don't bother storing an entirely empty segment. */
-  if( iEndBlockid==0 && nRootInfo==0 ) return SQLITE_OK;
-
-  return segdir_set(v, pWriter->iLevel, pWriter->idx,
-                    pWriter->iStartBlockid, pWriter->iEndBlockid,
-                    iEndBlockid, pRootInfo, nRootInfo);
-}
-
-static void leafWriterDestroy(LeafWriter *pWriter){
-  if( pWriter->has_parent ) interiorWriterDestroy(&pWriter->parentWriter);
-  dataBufferDestroy(&pWriter->term);
-  dataBufferDestroy(&pWriter->data);
-}
-
-/* Encode a term into the leafWriter, delta-encoding as appropriate.
-** Returns the length of the new term which distinguishes it from the
-** previous term, which can be used to set nTermDistinct when a node
-** boundary is crossed.
-*/
-static int leafWriterEncodeTerm(LeafWriter *pWriter,
-                                const char *pTerm, int nTerm){
-  char c[VARINT_MAX+VARINT_MAX];
-  int n, nPrefix = 0;
-
-  assert( nTerm>0 );
-  while( nPrefix<pWriter->term.nData &&
-         pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
-    nPrefix++;
-    /* Failing this implies that the terms weren't in order. */
-    assert( nPrefix<nTerm );
-  }
-
-  if( pWriter->data.nData==0 ){
-    /* Encode the node header and leading term as:
-    **  varint(0)
-    **  varint(nTerm)
-    **  char pTerm[nTerm]
-    */
-    n = fts3PutVarint(c, '\0');
-    n += fts3PutVarint(c+n, nTerm);
-    dataBufferAppend2(&pWriter->data, c, n, pTerm, nTerm);
-  }else{
-    /* Delta-encode the term as:
-    **  varint(nPrefix)
-    **  varint(nSuffix)
-    **  char pTermSuffix[nSuffix]
-    */
-    n = fts3PutVarint(c, nPrefix);
-    n += fts3PutVarint(c+n, nTerm-nPrefix);
-    dataBufferAppend2(&pWriter->data, c, n, pTerm+nPrefix, nTerm-nPrefix);
-  }
-  dataBufferReplace(&pWriter->term, pTerm, nTerm);
-
-  return nPrefix+1;
-}
-
-/* Used to avoid a memmove when a large amount of doclist data is in
-** the buffer.  This constructs a node and term header before
-** iDoclistData and flushes the resulting complete node using
-** leafWriterInternalFlush().
-*/
-static int leafWriterInlineFlush(fulltext_vtab *v, LeafWriter *pWriter,
-                                 const char *pTerm, int nTerm,
-                                 int iDoclistData){
-  char c[VARINT_MAX+VARINT_MAX];
-  int iData, n = fts3PutVarint(c, 0);
-  n += fts3PutVarint(c+n, nTerm);
-
-  /* There should always be room for the header.  Even if pTerm shared
-  ** a substantial prefix with the previous term, the entire prefix
-  ** could be constructed from earlier data in the doclist, so there
-  ** should be room.
-  */
-  assert( iDoclistData>=n+nTerm );
-
-  iData = iDoclistData-(n+nTerm);
-  memcpy(pWriter->data.pData+iData, c, n);
-  memcpy(pWriter->data.pData+iData+n, pTerm, nTerm);
-
-  return leafWriterInternalFlush(v, pWriter, iData, pWriter->data.nData-iData);
-}
-
-/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
-** %_segments.
-*/
-static int leafWriterStepMerge(fulltext_vtab *v, LeafWriter *pWriter,
-                               const char *pTerm, int nTerm,
-                               DLReader *pReaders, int nReaders){
-  char c[VARINT_MAX+VARINT_MAX];
-  int iTermData = pWriter->data.nData, iDoclistData;
-  int i, nData, n, nActualData, nActual, rc, nTermDistinct;
-
-  ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
-  nTermDistinct = leafWriterEncodeTerm(pWriter, pTerm, nTerm);
-
-  /* Remember nTermDistinct if opening a new node. */
-  if( iTermData==0 ) pWriter->nTermDistinct = nTermDistinct;
-
-  iDoclistData = pWriter->data.nData;
-
-  /* Estimate the length of the merged doclist so we can leave space
-  ** to encode it.
-  */
-  for(i=0, nData=0; i<nReaders; i++){
-    nData += dlrAllDataBytes(&pReaders[i]);
-  }
-  n = fts3PutVarint(c, nData);
-  dataBufferAppend(&pWriter->data, c, n);
-
-  docListMerge(&pWriter->data, pReaders, nReaders);
-  ASSERT_VALID_DOCLIST(DL_DEFAULT,
-                       pWriter->data.pData+iDoclistData+n,
-                       pWriter->data.nData-iDoclistData-n, NULL);
-
-  /* The actual amount of doclist data at this point could be smaller
-  ** than the length we encoded.  Additionally, the space required to
-  ** encode this length could be smaller.  For small doclists, this is
-  ** not a big deal, we can just use memmove() to adjust things.
-  */
-  nActualData = pWriter->data.nData-(iDoclistData+n);
-  nActual = fts3PutVarint(c, nActualData);
-  assert( nActualData<=nData );
-  assert( nActual<=n );
-
-  /* If the new doclist is big enough for force a standalone leaf
-  ** node, we can immediately flush it inline without doing the
-  ** memmove().
-  */
-  /* TODO(shess) This test matches leafWriterStep(), which does this
-  ** test before it knows the cost to varint-encode the term and
-  ** doclist lengths.  At some point, change to
-  ** pWriter->data.nData-iTermData>STANDALONE_MIN.
-  */
-  if( nTerm+nActualData>STANDALONE_MIN ){
-    /* Push leaf node from before this term. */
-    if( iTermData>0 ){
-      rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
-      if( rc!=SQLITE_OK ) return rc;
-
-      pWriter->nTermDistinct = nTermDistinct;
-    }
-
-    /* Fix the encoded doclist length. */
-    iDoclistData += n - nActual;
-    memcpy(pWriter->data.pData+iDoclistData, c, nActual);
-
-    /* Push the standalone leaf node. */
-    rc = leafWriterInlineFlush(v, pWriter, pTerm, nTerm, iDoclistData);
-    if( rc!=SQLITE_OK ) return rc;
-
-    /* Leave the node empty. */
-    dataBufferReset(&pWriter->data);
-
-    return rc;
-  }
-
-  /* At this point, we know that the doclist was small, so do the
-  ** memmove if indicated.
-  */
-  if( nActual<n ){
-    memmove(pWriter->data.pData+iDoclistData+nActual,
-            pWriter->data.pData+iDoclistData+n,
-            pWriter->data.nData-(iDoclistData+n));
-    pWriter->data.nData -= n-nActual;
-  }
-
-  /* Replace written length with actual length. */
-  memcpy(pWriter->data.pData+iDoclistData, c, nActual);
-
-  /* If the node is too large, break things up. */
-  /* TODO(shess) This test matches leafWriterStep(), which does this
-  ** test before it knows the cost to varint-encode the term and
-  ** doclist lengths.  At some point, change to
-  ** pWriter->data.nData>LEAF_MAX.
-  */
-  if( iTermData+nTerm+nActualData>LEAF_MAX ){
-    /* Flush out the leading data as a node */
-    rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
-    if( rc!=SQLITE_OK ) return rc;
-
-    pWriter->nTermDistinct = nTermDistinct;
-
-    /* Rebuild header using the current term */
-    n = fts3PutVarint(pWriter->data.pData, 0);
-    n += fts3PutVarint(pWriter->data.pData+n, nTerm);
-    memcpy(pWriter->data.pData+n, pTerm, nTerm);
-    n += nTerm;
-
-    /* There should always be room, because the previous encoding
-    ** included all data necessary to construct the term.
-    */
-    assert( n<iDoclistData );
-    /* So long as STANDALONE_MIN is half or less of LEAF_MAX, the
-    ** following memcpy() is safe (as opposed to needing a memmove).
-    */
-    assert( 2*STANDALONE_MIN<=LEAF_MAX );
-    assert( n+pWriter->data.nData-iDoclistData<iDoclistData );
-    memcpy(pWriter->data.pData+n,
-           pWriter->data.pData+iDoclistData,
-           pWriter->data.nData-iDoclistData);
-    pWriter->data.nData -= iDoclistData-n;
-  }
-  ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
-
-  return SQLITE_OK;
-}
-
-/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
-** %_segments.
-*/
-/* TODO(shess) Revise writeZeroSegment() so that doclists are
-** constructed directly in pWriter->data.
-*/
-static int leafWriterStep(fulltext_vtab *v, LeafWriter *pWriter,
-                          const char *pTerm, int nTerm,
-                          const char *pData, int nData){
-  int rc;
-  DLReader reader;
-
-  dlrInit(&reader, DL_DEFAULT, pData, nData);
-  rc = leafWriterStepMerge(v, pWriter, pTerm, nTerm, &reader, 1);
-  dlrDestroy(&reader);
-
-  return rc;
-}
-
-
-/****************************************************************/
-/* LeafReader is used to iterate over an individual leaf node. */
-typedef struct LeafReader {
-  DataBuffer term;          /* copy of current term. */
-
-  const char *pData;        /* data for current term. */
-  int nData;
-} LeafReader;
-
-static void leafReaderDestroy(LeafReader *pReader){
-  dataBufferDestroy(&pReader->term);
-  SCRAMBLE(pReader);
-}
-
-static int leafReaderAtEnd(LeafReader *pReader){
-  return pReader->nData<=0;
-}
-
-/* Access the current term. */
-static int leafReaderTermBytes(LeafReader *pReader){
-  return pReader->term.nData;
-}
-static const char *leafReaderTerm(LeafReader *pReader){
-  assert( pReader->term.nData>0 );
-  return pReader->term.pData;
-}
-
-/* Access the doclist data for the current term. */
-static int leafReaderDataBytes(LeafReader *pReader){
-  int nData;
-  assert( pReader->term.nData>0 );
-  fts3GetVarint32(pReader->pData, &nData);
-  return nData;
-}
-static const char *leafReaderData(LeafReader *pReader){
-  int n, nData;
-  assert( pReader->term.nData>0 );
-  n = fts3GetVarint32(pReader->pData, &nData);
-  return pReader->pData+n;
-}
-
-static void leafReaderInit(const char *pData, int nData,
-                           LeafReader *pReader){
-  int nTerm, n;
-
-  assert( nData>0 );
-  assert( pData[0]=='\0' );
-
-  CLEAR(pReader);
-
-  /* Read the first term, skipping the header byte. */
-  n = fts3GetVarint32(pData+1, &nTerm);
-  dataBufferInit(&pReader->term, nTerm);
-  dataBufferReplace(&pReader->term, pData+1+n, nTerm);
-
-  /* Position after the first term. */
-  assert( 1+n+nTerm<nData );
-  pReader->pData = pData+1+n+nTerm;
-  pReader->nData = nData-1-n-nTerm;
-}
-
-/* Step the reader forward to the next term. */
-static void leafReaderStep(LeafReader *pReader){
-  int n, nData, nPrefix, nSuffix;
-  assert( !leafReaderAtEnd(pReader) );
-
-  /* Skip previous entry's data block. */
-  n = fts3GetVarint32(pReader->pData, &nData);
-  assert( n+nData<=pReader->nData );
-  pReader->pData += n+nData;
-  pReader->nData -= n+nData;
-
-  if( !leafReaderAtEnd(pReader) ){
-    /* Construct the new term using a prefix from the old term plus a
-    ** suffix from the leaf data.
-    */
-    n = fts3GetVarint32(pReader->pData, &nPrefix);
-    n += fts3GetVarint32(pReader->pData+n, &nSuffix);
-    assert( n+nSuffix<pReader->nData );
-    pReader->term.nData = nPrefix;
-    dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
-
-    pReader->pData += n+nSuffix;
-    pReader->nData -= n+nSuffix;
-  }
-}
-
-/* strcmp-style comparison of pReader's current term against pTerm.
-** If isPrefix, equality means equal through nTerm bytes.
-*/
-static int leafReaderTermCmp(LeafReader *pReader,
-                             const char *pTerm, int nTerm, int isPrefix){
-  int c, n = pReader->term.nData<nTerm ? pReader->term.nData : nTerm;
-  if( n==0 ){
-    if( pReader->term.nData>0 ) return -1;
-    if(nTerm>0 ) return 1;
-    return 0;
-  }
-
-  c = memcmp(pReader->term.pData, pTerm, n);
-  if( c!=0 ) return c;
-  if( isPrefix && n==nTerm ) return 0;
-  return pReader->term.nData - nTerm;
-}
-
-
-/****************************************************************/
-/* LeavesReader wraps LeafReader to allow iterating over the entire
-** leaf layer of the tree.
-*/
-typedef struct LeavesReader {
-  int idx;                  /* Index within the segment. */
-
-  sqlite3_stmt *pStmt;      /* Statement we're streaming leaves from. */
-  int eof;                  /* we've seen SQLITE_DONE from pStmt. */
-
-  LeafReader leafReader;    /* reader for the current leaf. */
-  DataBuffer rootData;      /* root data for inline. */
-} LeavesReader;
-
-/* Access the current term. */
-static int leavesReaderTermBytes(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderTermBytes(&pReader->leafReader);
-}
-static const char *leavesReaderTerm(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderTerm(&pReader->leafReader);
-}
-
-/* Access the doclist data for the current term. */
-static int leavesReaderDataBytes(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderDataBytes(&pReader->leafReader);
-}
-static const char *leavesReaderData(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderData(&pReader->leafReader);
-}
-
-static int leavesReaderAtEnd(LeavesReader *pReader){
-  return pReader->eof;
-}
-
-/* loadSegmentLeaves() may not read all the way to SQLITE_DONE, thus
-** leaving the statement handle open, which locks the table.
-*/
-/* TODO(shess) This "solution" is not satisfactory.  Really, there
-** should be check-in function for all statement handles which
-** arranges to call sqlite3_reset().  This most likely will require
-** modification to control flow all over the place, though, so for now
-** just punt.
-**
-** Note the the current system assumes that segment merges will run to
-** completion, which is why this particular probably hasn't arisen in
-** this case.  Probably a brittle assumption.
-*/
-static int leavesReaderReset(LeavesReader *pReader){
-  return sqlite3_reset(pReader->pStmt);
-}
-
-static void leavesReaderDestroy(LeavesReader *pReader){
-  /* If idx is -1, that means we're using a non-cached statement
-  ** handle in the optimize() case, so we need to release it.
-  */
-  if( pReader->pStmt!=NULL && pReader->idx==-1 ){
-    sqlite3_finalize(pReader->pStmt);
-  }
-  leafReaderDestroy(&pReader->leafReader);
-  dataBufferDestroy(&pReader->rootData);
-  SCRAMBLE(pReader);
-}
-
-/* Initialize pReader with the given root data (if iStartBlockid==0
-** the leaf data was entirely contained in the root), or from the
-** stream of blocks between iStartBlockid and iEndBlockid, inclusive.
-*/
-static int leavesReaderInit(fulltext_vtab *v,
-                            int idx,
-                            sqlite_int64 iStartBlockid,
-                            sqlite_int64 iEndBlockid,
-                            const char *pRootData, int nRootData,
-                            LeavesReader *pReader){
-  CLEAR(pReader);
-  pReader->idx = idx;
-
-  dataBufferInit(&pReader->rootData, 0);
-  if( iStartBlockid==0 ){
-    /* Entire leaf level fit in root data. */
-    dataBufferReplace(&pReader->rootData, pRootData, nRootData);
-    leafReaderInit(pReader->rootData.pData, pReader->rootData.nData,
-                   &pReader->leafReader);
-  }else{
-    sqlite3_stmt *s;
-    int rc = sql_get_leaf_statement(v, idx, &s);
-    if( rc!=SQLITE_OK ) return rc;
-
-    rc = sqlite3_bind_int64(s, 1, iStartBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-
-    rc = sqlite3_bind_int64(s, 2, iEndBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-
-    rc = sqlite3_step(s);
-    if( rc==SQLITE_DONE ){
-      pReader->eof = 1;
-      return SQLITE_OK;
-    }
-    if( rc!=SQLITE_ROW ) return rc;
-
-    pReader->pStmt = s;
-    leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
-                   sqlite3_column_bytes(pReader->pStmt, 0),
-                   &pReader->leafReader);
-  }
-  return SQLITE_OK;
-}
-
-/* Step the current leaf forward to the next term.  If we reach the
-** end of the current leaf, step forward to the next leaf block.
-*/
-static int leavesReaderStep(fulltext_vtab *v, LeavesReader *pReader){
-  assert( !leavesReaderAtEnd(pReader) );
-  leafReaderStep(&pReader->leafReader);
-
-  if( leafReaderAtEnd(&pReader->leafReader) ){
-    int rc;
-    if( pReader->rootData.pData ){
-      pReader->eof = 1;
-      return SQLITE_OK;
-    }
-    rc = sqlite3_step(pReader->pStmt);
-    if( rc!=SQLITE_ROW ){
-      pReader->eof = 1;
-      return rc==SQLITE_DONE ? SQLITE_OK : rc;
-    }
-    leafReaderDestroy(&pReader->leafReader);
-    leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
-                   sqlite3_column_bytes(pReader->pStmt, 0),
-                   &pReader->leafReader);
-  }
-  return SQLITE_OK;
-}
-
-/* Order LeavesReaders by their term, ignoring idx.  Readers at eof
-** always sort to the end.
-*/
-static int leavesReaderTermCmp(LeavesReader *lr1, LeavesReader *lr2){
-  if( leavesReaderAtEnd(lr1) ){
-    if( leavesReaderAtEnd(lr2) ) return 0;
-    return 1;
-  }
-  if( leavesReaderAtEnd(lr2) ) return -1;
-
-  return leafReaderTermCmp(&lr1->leafReader,
-                           leavesReaderTerm(lr2), leavesReaderTermBytes(lr2),
-                           0);
-}
-
-/* Similar to leavesReaderTermCmp(), with additional ordering by idx
-** so that older segments sort before newer segments.
-*/
-static int leavesReaderCmp(LeavesReader *lr1, LeavesReader *lr2){
-  int c = leavesReaderTermCmp(lr1, lr2);
-  if( c!=0 ) return c;
-  return lr1->idx-lr2->idx;
-}
-
-/* Assume that pLr[1]..pLr[nLr] are sorted.  Bubble pLr[0] into its
-** sorted position.
-*/
-static void leavesReaderReorder(LeavesReader *pLr, int nLr){
-  while( nLr>1 && leavesReaderCmp(pLr, pLr+1)>0 ){
-    LeavesReader tmp = pLr[0];
-    pLr[0] = pLr[1];
-    pLr[1] = tmp;
-    nLr--;
-    pLr++;
-  }
-}
-
-/* Initializes pReaders with the segments from level iLevel, returning
-** the number of segments in *piReaders.  Leaves pReaders in sorted
-** order.
-*/
-static int leavesReadersInit(fulltext_vtab *v, int iLevel,
-                             LeavesReader *pReaders, int *piReaders){
-  sqlite3_stmt *s;
-  int i, rc = sql_get_statement(v, SEGDIR_SELECT_LEVEL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  i = 0;
-  while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-    sqlite_int64 iStart = sqlite3_column_int64(s, 0);
-    sqlite_int64 iEnd = sqlite3_column_int64(s, 1);
-    const char *pRootData = sqlite3_column_blob(s, 2);
-    int nRootData = sqlite3_column_bytes(s, 2);
-
-    assert( i<MERGE_COUNT );
-    rc = leavesReaderInit(v, i, iStart, iEnd, pRootData, nRootData,
-                          &pReaders[i]);
-    if( rc!=SQLITE_OK ) break;
-
-    i++;
-  }
-  if( rc!=SQLITE_DONE ){
-    while( i-->0 ){
-      leavesReaderDestroy(&pReaders[i]);
-    }
-    return rc;
-  }
-
-  *piReaders = i;
-
-  /* Leave our results sorted by term, then age. */
-  while( i-- ){
-    leavesReaderReorder(pReaders+i, *piReaders-i);
-  }
-  return SQLITE_OK;
-}
-
-/* Merge doclists from pReaders[nReaders] into a single doclist, which
-** is written to pWriter.  Assumes pReaders is ordered oldest to
-** newest.
-*/
-/* TODO(shess) Consider putting this inline in segmentMerge(). */
-static int leavesReadersMerge(fulltext_vtab *v,
-                              LeavesReader *pReaders, int nReaders,
-                              LeafWriter *pWriter){
-  DLReader dlReaders[MERGE_COUNT];
-  const char *pTerm = leavesReaderTerm(pReaders);
-  int i, nTerm = leavesReaderTermBytes(pReaders);
-
-  assert( nReaders<=MERGE_COUNT );
-
-  for(i=0; i<nReaders; i++){
-    dlrInit(&dlReaders[i], DL_DEFAULT,
-            leavesReaderData(pReaders+i),
-            leavesReaderDataBytes(pReaders+i));
-  }
-
-  return leafWriterStepMerge(v, pWriter, pTerm, nTerm, dlReaders, nReaders);
-}
-
-/* Forward ref due to mutual recursion with segdirNextIndex(). */
-static int segmentMerge(fulltext_vtab *v, int iLevel);
-
-/* Put the next available index at iLevel into *pidx.  If iLevel
-** already has MERGE_COUNT segments, they are merged to a higher
-** level to make room.
-*/
-static int segdirNextIndex(fulltext_vtab *v, int iLevel, int *pidx){
-  int rc = segdir_max_index(v, iLevel, pidx);
-  if( rc==SQLITE_DONE ){              /* No segments at iLevel. */
-    *pidx = 0;
-  }else if( rc==SQLITE_ROW ){
-    if( *pidx==(MERGE_COUNT-1) ){
-      rc = segmentMerge(v, iLevel);
-      if( rc!=SQLITE_OK ) return rc;
-      *pidx = 0;
-    }else{
-      (*pidx)++;
-    }
-  }else{
-    return rc;
-  }
-  return SQLITE_OK;
-}
-
-/* Merge MERGE_COUNT segments at iLevel into a new segment at
-** iLevel+1.  If iLevel+1 is already full of segments, those will be
-** merged to make room.
-*/
-static int segmentMerge(fulltext_vtab *v, int iLevel){
-  LeafWriter writer;
-  LeavesReader lrs[MERGE_COUNT];
-  int i, rc, idx = 0;
-
-  /* Determine the next available segment index at the next level,
-  ** merging as necessary.
-  */
-  rc = segdirNextIndex(v, iLevel+1, &idx);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* TODO(shess) This assumes that we'll always see exactly
-  ** MERGE_COUNT segments to merge at a given level.  That will be
-  ** broken if we allow the developer to request preemptive or
-  ** deferred merging.
-  */
-  memset(&lrs, '\0', sizeof(lrs));
-  rc = leavesReadersInit(v, iLevel, lrs, &i);
-  if( rc!=SQLITE_OK ) return rc;
-  assert( i==MERGE_COUNT );
-
-  leafWriterInit(iLevel+1, idx, &writer);
-
-  /* Since leavesReaderReorder() pushes readers at eof to the end,
-  ** when the first reader is empty, all will be empty.
-  */
-  while( !leavesReaderAtEnd(lrs) ){
-    /* Figure out how many readers share their next term. */
-    for(i=1; i<MERGE_COUNT && !leavesReaderAtEnd(lrs+i); i++){
-      if( 0!=leavesReaderTermCmp(lrs, lrs+i) ) break;
-    }
-
-    rc = leavesReadersMerge(v, lrs, i, &writer);
-    if( rc!=SQLITE_OK ) goto err;
-
-    /* Step forward those that were merged. */
-    while( i-->0 ){
-      rc = leavesReaderStep(v, lrs+i);
-      if( rc!=SQLITE_OK ) goto err;
-
-      /* Reorder by term, then by age. */
-      leavesReaderReorder(lrs+i, MERGE_COUNT-i);
-    }
-  }
-
-  for(i=0; i<MERGE_COUNT; i++){
-    leavesReaderDestroy(&lrs[i]);
-  }
-
-  rc = leafWriterFinalize(v, &writer);
-  leafWriterDestroy(&writer);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Delete the merged segment data. */
-  return segdir_delete(v, iLevel);
-
- err:
-  for(i=0; i<MERGE_COUNT; i++){
-    leavesReaderDestroy(&lrs[i]);
-  }
-  leafWriterDestroy(&writer);
-  return rc;
-}
-
-/* Accumulate the union of *acc and *pData into *acc. */
-static void docListAccumulateUnion(DataBuffer *acc,
-                                   const char *pData, int nData) {
-  DataBuffer tmp = *acc;
-  dataBufferInit(acc, tmp.nData+nData);
-  docListUnion(tmp.pData, tmp.nData, pData, nData, acc);
-  dataBufferDestroy(&tmp);
-}
-
-/* TODO(shess) It might be interesting to explore different merge
-** strategies, here.  For instance, since this is a sorted merge, we
-** could easily merge many doclists in parallel.  With some
-** comprehension of the storage format, we could merge all of the
-** doclists within a leaf node directly from the leaf node's storage.
-** It may be worthwhile to merge smaller doclists before larger
-** doclists, since they can be traversed more quickly - but the
-** results may have less overlap, making them more expensive in a
-** different way.
-*/
-
-/* Scan pReader for pTerm/nTerm, and merge the term's doclist over
-** *out (any doclists with duplicate docids overwrite those in *out).
-** Internal function for loadSegmentLeaf().
-*/
-static int loadSegmentLeavesInt(fulltext_vtab *v, LeavesReader *pReader,
-                                const char *pTerm, int nTerm, int isPrefix,
-                                DataBuffer *out){
-  /* doclist data is accumulated into pBuffers similar to how one does
-  ** increment in binary arithmetic.  If index 0 is empty, the data is
-  ** stored there.  If there is data there, it is merged and the
-  ** results carried into position 1, with further merge-and-carry
-  ** until an empty position is found.
-  */
-  DataBuffer *pBuffers = NULL;
-  int nBuffers = 0, nMaxBuffers = 0, rc;
-
-  assert( nTerm>0 );
-
-  for(rc=SQLITE_OK; rc==SQLITE_OK && !leavesReaderAtEnd(pReader);
-      rc=leavesReaderStep(v, pReader)){
-    /* TODO(shess) Really want leavesReaderTermCmp(), but that name is
-    ** already taken to compare the terms of two LeavesReaders.  Think
-    ** on a better name.  [Meanwhile, break encapsulation rather than
-    ** use a confusing name.]
-    */
-    int c = leafReaderTermCmp(&pReader->leafReader, pTerm, nTerm, isPrefix);
-    if( c>0 ) break;      /* Past any possible matches. */
-    if( c==0 ){
-      const char *pData = leavesReaderData(pReader);
-      int iBuffer, nData = leavesReaderDataBytes(pReader);
-
-      /* Find the first empty buffer. */
-      for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
-        if( 0==pBuffers[iBuffer].nData ) break;
-      }
-
-      /* Out of buffers, add an empty one. */
-      if( iBuffer==nBuffers ){
-        if( nBuffers==nMaxBuffers ){
-          DataBuffer *p;
-          nMaxBuffers += 20;
-
-          /* Manual realloc so we can handle NULL appropriately. */
-          p = sqlite3_malloc(nMaxBuffers*sizeof(*pBuffers));
-          if( p==NULL ){
-            rc = SQLITE_NOMEM;
-            break;
-          }
-
-          if( nBuffers>0 ){
-            assert(pBuffers!=NULL);
-            memcpy(p, pBuffers, nBuffers*sizeof(*pBuffers));
-            sqlite3_free(pBuffers);
-          }
-          pBuffers = p;
-        }
-        dataBufferInit(&(pBuffers[nBuffers]), 0);
-        nBuffers++;
-      }
-
-      /* At this point, must have an empty at iBuffer. */
-      assert(iBuffer<nBuffers && pBuffers[iBuffer].nData==0);
-
-      /* If empty was first buffer, no need for merge logic. */
-      if( iBuffer==0 ){
-        dataBufferReplace(&(pBuffers[0]), pData, nData);
-      }else{
-        /* pAcc is the empty buffer the merged data will end up in. */
-        DataBuffer *pAcc = &(pBuffers[iBuffer]);
-        DataBuffer *p = &(pBuffers[0]);
-
-        /* Handle position 0 specially to avoid need to prime pAcc
-        ** with pData/nData.
-        */
-        dataBufferSwap(p, pAcc);
-        docListAccumulateUnion(pAcc, pData, nData);
-
-        /* Accumulate remaining doclists into pAcc. */
-        for(++p; p<pAcc; ++p){
-          docListAccumulateUnion(pAcc, p->pData, p->nData);
-
-          /* dataBufferReset() could allow a large doclist to blow up
-          ** our memory requirements.
-          */
-          if( p->nCapacity<1024 ){
-            dataBufferReset(p);
-          }else{
-            dataBufferDestroy(p);
-            dataBufferInit(p, 0);
-          }
-        }
-      }
-    }
-  }
-
-  /* Union all the doclists together into *out. */
-  /* TODO(shess) What if *out is big?  Sigh. */
-  if( rc==SQLITE_OK && nBuffers>0 ){
-    int iBuffer;
-    for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
-      if( pBuffers[iBuffer].nData>0 ){
-        if( out->nData==0 ){
-          dataBufferSwap(out, &(pBuffers[iBuffer]));
-        }else{
-          docListAccumulateUnion(out, pBuffers[iBuffer].pData,
-                                 pBuffers[iBuffer].nData);
-        }
-      }
-    }
-  }
-
-  while( nBuffers-- ){
-    dataBufferDestroy(&(pBuffers[nBuffers]));
-  }
-  if( pBuffers!=NULL ) sqlite3_free(pBuffers);
-
-  return rc;
-}
-
-/* Call loadSegmentLeavesInt() with pData/nData as input. */
-static int loadSegmentLeaf(fulltext_vtab *v, const char *pData, int nData,
-                           const char *pTerm, int nTerm, int isPrefix,
-                           DataBuffer *out){
-  LeavesReader reader;
-  int rc;
-
-  assert( nData>1 );
-  assert( *pData=='\0' );
-  rc = leavesReaderInit(v, 0, 0, 0, pData, nData, &reader);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
-  leavesReaderReset(&reader);
-  leavesReaderDestroy(&reader);
-  return rc;
-}
-
-/* Call loadSegmentLeavesInt() with the leaf nodes from iStartLeaf to
-** iEndLeaf (inclusive) as input, and merge the resulting doclist into
-** out.
-*/
-static int loadSegmentLeaves(fulltext_vtab *v,
-                             sqlite_int64 iStartLeaf, sqlite_int64 iEndLeaf,
-                             const char *pTerm, int nTerm, int isPrefix,
-                             DataBuffer *out){
-  int rc;
-  LeavesReader reader;
-
-  assert( iStartLeaf<=iEndLeaf );
-  rc = leavesReaderInit(v, 0, iStartLeaf, iEndLeaf, NULL, 0, &reader);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
-  leavesReaderReset(&reader);
-  leavesReaderDestroy(&reader);
-  return rc;
-}
-
-/* Taking pData/nData as an interior node, find the sequence of child
-** nodes which could include pTerm/nTerm/isPrefix.  Note that the
-** interior node terms logically come between the blocks, so there is
-** one more blockid than there are terms (that block contains terms >=
-** the last interior-node term).
-*/
-/* TODO(shess) The calling code may already know that the end child is
-** not worth calculating, because the end may be in a later sibling
-** node.  Consider whether breaking symmetry is worthwhile.  I suspect
-** it is not worthwhile.
-*/
-static void getChildrenContaining(const char *pData, int nData,
-                                  const char *pTerm, int nTerm, int isPrefix,
-                                  sqlite_int64 *piStartChild,
-                                  sqlite_int64 *piEndChild){
-  InteriorReader reader;
-
-  assert( nData>1 );
-  assert( *pData!='\0' );
-  interiorReaderInit(pData, nData, &reader);
-
-  /* Scan for the first child which could contain pTerm/nTerm. */
-  while( !interiorReaderAtEnd(&reader) ){
-    if( interiorReaderTermCmp(&reader, pTerm, nTerm, 0)>0 ) break;
-    interiorReaderStep(&reader);
-  }
-  *piStartChild = interiorReaderCurrentBlockid(&reader);
-
-  /* Keep scanning to find a term greater than our term, using prefix
-  ** comparison if indicated.  If isPrefix is false, this will be the
-  ** same blockid as the starting block.
-  */
-  while( !interiorReaderAtEnd(&reader) ){
-    if( interiorReaderTermCmp(&reader, pTerm, nTerm, isPrefix)>0 ) break;
-    interiorReaderStep(&reader);
-  }
-  *piEndChild = interiorReaderCurrentBlockid(&reader);
-
-  interiorReaderDestroy(&reader);
-
-  /* Children must ascend, and if !prefix, both must be the same. */
-  assert( *piEndChild>=*piStartChild );
-  assert( isPrefix || *piStartChild==*piEndChild );
-}
-
-/* Read block at iBlockid and pass it with other params to
-** getChildrenContaining().
-*/
-static int loadAndGetChildrenContaining(
-  fulltext_vtab *v,
-  sqlite_int64 iBlockid,
-  const char *pTerm, int nTerm, int isPrefix,
-  sqlite_int64 *piStartChild, sqlite_int64 *piEndChild
+static int fts3ColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
 ){
-  sqlite3_stmt *s = NULL;
-  int rc;
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
+  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
 
-  assert( iBlockid!=0 );
-  assert( pTerm!=NULL );
-  assert( nTerm!=0 );        /* TODO(shess) Why not allow this? */
-  assert( piStartChild!=NULL );
-  assert( piEndChild!=NULL );
+  /* The column value supplied by SQLite must be in range. */
+  assert( iCol>=0 && iCol<=p->nColumn+2 );
 
-  rc = sql_get_statement(v, BLOCK_SELECT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_ERROR;
-  if( rc!=SQLITE_ROW ) return rc;
-
-  getChildrenContaining(sqlite3_column_blob(s, 0), sqlite3_column_bytes(s, 0),
-                        pTerm, nTerm, isPrefix, piStartChild, piEndChild);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain
-   * locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-
-  return SQLITE_OK;
-}
-
-/* Traverse the tree represented by pData[nData] looking for
-** pTerm[nTerm], placing its doclist into *out.  This is internal to
-** loadSegment() to make error-handling cleaner.
-*/
-static int loadSegmentInt(fulltext_vtab *v, const char *pData, int nData,
-                          sqlite_int64 iLeavesEnd,
-                          const char *pTerm, int nTerm, int isPrefix,
-                          DataBuffer *out){
-  /* Special case where root is a leaf. */
-  if( *pData=='\0' ){
-    return loadSegmentLeaf(v, pData, nData, pTerm, nTerm, isPrefix, out);
-  }else{
-    int rc;
-    sqlite_int64 iStartChild, iEndChild;
-
-    /* Process pData as an interior node, then loop down the tree
-    ** until we find the set of leaf nodes to scan for the term.
+  if( iCol==p->nColumn+1 ){
+    /* This call is a request for the "docid" column. Since "docid" is an 
+    ** alias for "rowid", use the xRowid() method to obtain the value.
     */
-    getChildrenContaining(pData, nData, pTerm, nTerm, isPrefix,
-                          &iStartChild, &iEndChild);
-    while( iStartChild>iLeavesEnd ){
-      sqlite_int64 iNextStart, iNextEnd;
-      rc = loadAndGetChildrenContaining(v, iStartChild, pTerm, nTerm, isPrefix,
-                                        &iNextStart, &iNextEnd);
-      if( rc!=SQLITE_OK ) return rc;
+    sqlite3_result_int64(pCtx, pCsr->iPrevId);
+  }else if( iCol==p->nColumn ){
+    /* The extra column whose name is the same as the table.
+    ** Return a blob which is a pointer to the cursor.  */
+    sqlite3_result_blob(pCtx, &pCsr, sizeof(pCsr), SQLITE_TRANSIENT);
+  }else if( iCol==p->nColumn+2 && pCsr->pExpr ){
+    sqlite3_result_int64(pCtx, pCsr->iLangid);
+  }else{
+    /* The requested column is either a user column (one that contains 
+    ** indexed data), or the language-id column.  */
+    rc = fts3CursorSeek(0, pCsr);
 
-      /* If we've branched, follow the end branch, too. */
-      if( iStartChild!=iEndChild ){
-        sqlite_int64 iDummy;
-        rc = loadAndGetChildrenContaining(v, iEndChild, pTerm, nTerm, isPrefix,
-                                          &iDummy, &iNextEnd);
-        if( rc!=SQLITE_OK ) return rc;
-      }
-
-      assert( iNextStart<=iNextEnd );
-      iStartChild = iNextStart;
-      iEndChild = iNextEnd;
-    }
-    assert( iStartChild<=iLeavesEnd );
-    assert( iEndChild<=iLeavesEnd );
-
-    /* Scan through the leaf segments for doclists. */
-    return loadSegmentLeaves(v, iStartChild, iEndChild,
-                             pTerm, nTerm, isPrefix, out);
-  }
-}
-
-/* Call loadSegmentInt() to collect the doclist for pTerm/nTerm, then
-** merge its doclist over *out (any duplicate doclists read from the
-** segment rooted at pData will overwrite those in *out).
-*/
-/* TODO(shess) Consider changing this to determine the depth of the
-** leaves using either the first characters of interior nodes (when
-** ==1, we're one level above the leaves), or the first character of
-** the root (which will describe the height of the tree directly).
-** Either feels somewhat tricky to me.
-*/
-/* TODO(shess) The current merge is likely to be slow for large
-** doclists (though it should process from newest/smallest to
-** oldest/largest, so it may not be that bad).  It might be useful to
-** modify things to allow for N-way merging.  This could either be
-** within a segment, with pairwise merges across segments, or across
-** all segments at once.
-*/
-static int loadSegment(fulltext_vtab *v, const char *pData, int nData,
-                       sqlite_int64 iLeavesEnd,
-                       const char *pTerm, int nTerm, int isPrefix,
-                       DataBuffer *out){
-  DataBuffer result;
-  int rc;
-
-  assert( nData>1 );
-
-  /* This code should never be called with buffered updates. */
-  assert( v->nPendingData<0 );
-
-  dataBufferInit(&result, 0);
-  rc = loadSegmentInt(v, pData, nData, iLeavesEnd,
-                      pTerm, nTerm, isPrefix, &result);
-  if( rc==SQLITE_OK && result.nData>0 ){
-    if( out->nData==0 ){
-      DataBuffer tmp = *out;
-      *out = result;
-      result = tmp;
-    }else{
-      DataBuffer merged;
-      DLReader readers[2];
-
-      dlrInit(&readers[0], DL_DEFAULT, out->pData, out->nData);
-      dlrInit(&readers[1], DL_DEFAULT, result.pData, result.nData);
-      dataBufferInit(&merged, out->nData+result.nData);
-      docListMerge(&merged, readers, 2);
-      dataBufferDestroy(out);
-      *out = merged;
-      dlrDestroy(&readers[0]);
-      dlrDestroy(&readers[1]);
-    }
-  }
-  dataBufferDestroy(&result);
-  return rc;
-}
-
-/* Scan the database and merge together the posting lists for the term
-** into *out.
-*/
-static int termSelect(
-  fulltext_vtab *v, 
-  int iColumn,
-  const char *pTerm, int nTerm,             /* Term to query for */
-  int isPrefix,                             /* True for a prefix search */
-  DocListType iType, 
-  DataBuffer *out                           /* Write results here */
-){
-  DataBuffer doclist;
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* This code should never be called with buffered updates. */
-  assert( v->nPendingData<0 );
-
-  dataBufferInit(&doclist, 0);
-  dataBufferInit(out, 0);
-
-  /* Traverse the segments from oldest to newest so that newer doclist
-  ** elements for given docids overwrite older elements.
-  */
-  while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-    const char *pData = sqlite3_column_blob(s, 2);
-    const int nData = sqlite3_column_bytes(s, 2);
-    const sqlite_int64 iLeavesEnd = sqlite3_column_int64(s, 1);
-    rc = loadSegment(v, pData, nData, iLeavesEnd, pTerm, nTerm, isPrefix,
-                     &doclist);
-    if( rc!=SQLITE_OK ) goto err;
-  }
-  if( rc==SQLITE_DONE ){
-    if( doclist.nData!=0 ){
-      /* TODO(shess) The old term_select_all() code applied the column
-      ** restrict as we merged segments, leading to smaller buffers.
-      ** This is probably worthwhile to bring back, once the new storage
-      ** system is checked in.
-      */
-      if( iColumn==v->nColumn) iColumn = -1;
-      docListTrim(DL_DEFAULT, doclist.pData, doclist.nData,
-                  iColumn, iType, out);
-    }
-    rc = SQLITE_OK;
-  }
-
- err:
-  dataBufferDestroy(&doclist);
-  return rc;
-}
-
-/****************************************************************/
-/* Used to hold hashtable data for sorting. */
-typedef struct TermData {
-  const char *pTerm;
-  int nTerm;
-  DLCollector *pCollector;
-} TermData;
-
-/* Orders TermData elements in strcmp fashion ( <0 for less-than, 0
-** for equal, >0 for greater-than).
-*/
-static int termDataCmp(const void *av, const void *bv){
-  const TermData *a = (const TermData *)av;
-  const TermData *b = (const TermData *)bv;
-  int n = a->nTerm<b->nTerm ? a->nTerm : b->nTerm;
-  int c = memcmp(a->pTerm, b->pTerm, n);
-  if( c!=0 ) return c;
-  return a->nTerm-b->nTerm;
-}
-
-/* Order pTerms data by term, then write a new level 0 segment using
-** LeafWriter.
-*/
-static int writeZeroSegment(fulltext_vtab *v, fts3Hash *pTerms){
-  fts3HashElem *e;
-  int idx, rc, i, n;
-  TermData *pData;
-  LeafWriter writer;
-  DataBuffer dl;
-
-  /* Determine the next index at level 0, merging as necessary. */
-  rc = segdirNextIndex(v, 0, &idx);
-  if( rc!=SQLITE_OK ) return rc;
-
-  n = fts3HashCount(pTerms);
-  pData = sqlite3_malloc(n*sizeof(TermData));
-
-  for(i = 0, e = fts3HashFirst(pTerms); e; i++, e = fts3HashNext(e)){
-    assert( i<n );
-    pData[i].pTerm = fts3HashKey(e);
-    pData[i].nTerm = fts3HashKeysize(e);
-    pData[i].pCollector = fts3HashData(e);
-  }
-  assert( i==n );
-
-  /* TODO(shess) Should we allow user-defined collation sequences,
-  ** here?  I think we only need that once we support prefix searches.
-  */
-  if( n>1 ) qsort(pData, n, sizeof(*pData), termDataCmp);
-
-  /* TODO(shess) Refactor so that we can write directly to the segment
-  ** DataBuffer, as happens for segment merges.
-  */
-  leafWriterInit(0, idx, &writer);
-  dataBufferInit(&dl, 0);
-  for(i=0; i<n; i++){
-    dataBufferReset(&dl);
-    dlcAddDoclist(pData[i].pCollector, &dl);
-    rc = leafWriterStep(v, &writer,
-                        pData[i].pTerm, pData[i].nTerm, dl.pData, dl.nData);
-    if( rc!=SQLITE_OK ) goto err;
-  }
-  rc = leafWriterFinalize(v, &writer);
-
- err:
-  dataBufferDestroy(&dl);
-  sqlite3_free(pData);
-  leafWriterDestroy(&writer);
-  return rc;
-}
-
-/* If pendingTerms has data, free it. */
-static int clearPendingTerms(fulltext_vtab *v){
-  if( v->nPendingData>=0 ){
-    fts3HashElem *e;
-    for(e=fts3HashFirst(&v->pendingTerms); e; e=fts3HashNext(e)){
-      dlcDelete(fts3HashData(e));
-    }
-    fts3HashClear(&v->pendingTerms);
-    v->nPendingData = -1;
-  }
-  return SQLITE_OK;
-}
-
-/* If pendingTerms has data, flush it to a level-zero segment, and
-** free it.
-*/
-static int flushPendingTerms(fulltext_vtab *v){
-  if( v->nPendingData>=0 ){
-    int rc = writeZeroSegment(v, &v->pendingTerms);
-    if( rc==SQLITE_OK ) clearPendingTerms(v);
-    return rc;
-  }
-  return SQLITE_OK;
-}
-
-/* If pendingTerms is "too big", or docid is out of order, flush it.
-** Regardless, be certain that pendingTerms is initialized for use.
-*/
-static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid){
-  /* TODO(shess) Explore whether partially flushing the buffer on
-  ** forced-flush would provide better performance.  I suspect that if
-  ** we ordered the doclists by size and flushed the largest until the
-  ** buffer was half empty, that would let the less frequent terms
-  ** generate longer doclists.
-  */
-  if( iDocid<=v->iPrevDocid || v->nPendingData>kPendingThreshold ){
-    int rc = flushPendingTerms(v);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-  if( v->nPendingData<0 ){
-    fts3HashInit(&v->pendingTerms, FTS3_HASH_STRING, 1);
-    v->nPendingData = 0;
-  }
-  v->iPrevDocid = iDocid;
-  return SQLITE_OK;
-}
-
-/* This function implements the xUpdate callback; it is the top-level entry
- * point for inserting, deleting or updating a row in a full-text table. */
-static int fulltextUpdate(sqlite3_vtab *pVtab, int nArg, sqlite3_value **ppArg,
-                          sqlite_int64 *pRowid){
-  fulltext_vtab *v = (fulltext_vtab *) pVtab;
-  int rc;
-
-  FTSTRACE(("FTS3 Update %p\n", pVtab));
-
-  if( nArg<2 ){
-    rc = index_delete(v, sqlite3_value_int64(ppArg[0]));
     if( rc==SQLITE_OK ){
-      /* If we just deleted the last row in the table, clear out the
-      ** index data.
-      */
-      rc = content_exists(v);
-      if( rc==SQLITE_ROW ){
-        rc = SQLITE_OK;
-      }else if( rc==SQLITE_DONE ){
-        /* Clear the pending terms so we don't flush a useless level-0
-        ** segment when the transaction closes.
-        */
-        rc = clearPendingTerms(v);
-        if( rc==SQLITE_OK ){
-          rc = segdir_delete_all(v);
+      if( iCol==p->nColumn+2 ){
+        int iLangid = 0;
+        if( p->zLanguageid ){
+          iLangid = sqlite3_column_int(pCsr->pStmt, p->nColumn+1);
         }
+        sqlite3_result_int(pCtx, iLangid);
+      }else if( sqlite3_data_count(pCsr->pStmt)>(iCol+1) ){
+        sqlite3_result_value(pCtx, sqlite3_column_value(pCsr->pStmt, iCol+1));
       }
     }
-  } else if( sqlite3_value_type(ppArg[0]) != SQLITE_NULL ){
-    /* An update:
-     * ppArg[0] = old rowid
-     * ppArg[1] = new rowid
-     * ppArg[2..2+v->nColumn-1] = values
-     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
-     * ppArg[2+v->nColumn+1] = value for docid
-     */
-    sqlite_int64 rowid = sqlite3_value_int64(ppArg[0]);
-    if( sqlite3_value_type(ppArg[1]) != SQLITE_INTEGER ||
-        sqlite3_value_int64(ppArg[1]) != rowid ){
-      rc = SQLITE_ERROR;  /* we don't allow changing the rowid */
-    }else if( sqlite3_value_type(ppArg[2+v->nColumn+1]) != SQLITE_INTEGER ||
-              sqlite3_value_int64(ppArg[2+v->nColumn+1]) != rowid ){
-      rc = SQLITE_ERROR;  /* we don't allow changing the docid */
-    }else{
-      assert( nArg==2+v->nColumn+2);
-      rc = index_update(v, rowid, &ppArg[2]);
-    }
-  } else {
-    /* An insert:
-     * ppArg[1] = requested rowid
-     * ppArg[2..2+v->nColumn-1] = values
-     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
-     * ppArg[2+v->nColumn+1] = value for docid
-     */
-    sqlite3_value *pRequestDocid = ppArg[2+v->nColumn+1];
-    assert( nArg==2+v->nColumn+2);
-    if( SQLITE_NULL != sqlite3_value_type(pRequestDocid) &&
-        SQLITE_NULL != sqlite3_value_type(ppArg[1]) ){
-      /* TODO(shess) Consider allowing this to work if the values are
-      ** identical.  I'm inclined to discourage that usage, though,
-      ** given that both rowid and docid are special columns.  Better
-      ** would be to define one or the other as the default winner,
-      ** but should it be fts3-centric (docid) or SQLite-centric
-      ** (rowid)?
-      */
-      rc = SQLITE_ERROR;
-    }else{
-      if( SQLITE_NULL == sqlite3_value_type(pRequestDocid) ){
-        pRequestDocid = ppArg[1];
-      }
-      rc = index_insert(v, pRequestDocid, &ppArg[2], pRowid);
-    }
   }
 
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
   return rc;
 }
 
-static int fulltextSync(sqlite3_vtab *pVtab){
-  FTSTRACE(("FTS3 xSync()\n"));
-  return flushPendingTerms((fulltext_vtab *)pVtab);
+/* 
+** This function is the implementation of the xUpdate callback used by 
+** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
+** inserted, updated or deleted.
+*/
+static int fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  return sqlite3Fts3UpdateMethod(pVtab, nArg, apVal, pRowid);
 }
 
-static int fulltextBegin(sqlite3_vtab *pVtab){
-  fulltext_vtab *v = (fulltext_vtab *) pVtab;
-  FTSTRACE(("FTS3 xBegin()\n"));
+/*
+** Implementation of xSync() method. Flush the contents of the pending-terms
+** hash-table to the database.
+*/
+static int fts3SyncMethod(sqlite3_vtab *pVtab){
 
-  /* Any buffered updates should have been cleared by the previous
-  ** transaction.
+  /* Following an incremental-merge operation, assuming that the input
+  ** segments are not completely consumed (the usual case), they are updated
+  ** in place to remove the entries that have already been merged. This
+  ** involves updating the leaf block that contains the smallest unmerged
+  ** entry and each block (if any) between the leaf and the root node. So
+  ** if the height of the input segment b-trees is N, and input segments
+  ** are merged eight at a time, updating the input segments at the end
+  ** of an incremental-merge requires writing (8*(1+N)) blocks. N is usually
+  ** small - often between 0 and 2. So the overhead of the incremental
+  ** merge is somewhere between 8 and 24 blocks. To avoid this overhead
+  ** dwarfing the actual productive work accomplished, the incremental merge
+  ** is only attempted if it will write at least 64 leaf blocks. Hence
+  ** nMinMerge.
+  **
+  ** Of course, updating the input segments also involves deleting a bunch
+  ** of blocks from the segments table. But this is not considered overhead
+  ** as it would also be required by a crisis-merge that used the same input 
+  ** segments.
   */
-  assert( v->nPendingData<0 );
-  return clearPendingTerms(v);
+  const u32 nMinMerge = 64;       /* Minimum amount of incr-merge work to do */
+
+  Fts3Table *p = (Fts3Table*)pVtab;
+  int rc = sqlite3Fts3PendingTermsFlush(p);
+
+  if( rc==SQLITE_OK && p->bAutoincrmerge==1 && p->nLeafAdd>(nMinMerge/16) ){
+    int mxLevel = 0;              /* Maximum relative level value in db */
+    int A;                        /* Incr-merge parameter A */
+
+    rc = sqlite3Fts3MaxLevel(p, &mxLevel);
+    assert( rc==SQLITE_OK || mxLevel==0 );
+    A = p->nLeafAdd * mxLevel;
+    A += (A/2);
+    if( A>(int)nMinMerge ) rc = sqlite3Fts3Incrmerge(p, A, 8);
+  }
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
 }
 
-static int fulltextCommit(sqlite3_vtab *pVtab){
-  fulltext_vtab *v = (fulltext_vtab *) pVtab;
-  FTSTRACE(("FTS3 xCommit()\n"));
-
-  /* Buffered updates should have been cleared by fulltextSync(). */
-  assert( v->nPendingData<0 );
-  return clearPendingTerms(v);
+/*
+** Implementation of xBegin() method. This is a no-op.
+*/
+static int fts3BeginMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  UNUSED_PARAMETER(pVtab);
+  assert( p->pSegments==0 );
+  assert( p->nPendingData==0 );
+  assert( p->inTransaction!=1 );
+  TESTONLY( p->inTransaction = 1 );
+  TESTONLY( p->mxSavepoint = -1; );
+  p->nLeafAdd = 0;
+  return SQLITE_OK;
 }
 
-static int fulltextRollback(sqlite3_vtab *pVtab){
-  FTSTRACE(("FTS3 xRollback()\n"));
-  return clearPendingTerms((fulltext_vtab *)pVtab);
+/*
+** Implementation of xCommit() method. This is a no-op. The contents of
+** the pending-terms hash-table have already been flushed into the database
+** by fts3SyncMethod().
+*/
+static int fts3CommitMethod(sqlite3_vtab *pVtab){
+  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
+  UNUSED_PARAMETER(pVtab);
+  assert( p->nPendingData==0 );
+  assert( p->inTransaction!=0 );
+  assert( p->pSegments==0 );
+  TESTONLY( p->inTransaction = 0 );
+  TESTONLY( p->mxSavepoint = -1; );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xRollback(). Discard the contents of the pending-terms
+** hash-table. Any changes made to the database are reverted by SQLite.
+*/
+static int fts3RollbackMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  sqlite3Fts3PendingTermsClear(p);
+  assert( p->inTransaction!=0 );
+  TESTONLY( p->inTransaction = 0 );
+  TESTONLY( p->mxSavepoint = -1; );
+  return SQLITE_OK;
+}
+
+/*
+** When called, *ppPoslist must point to the byte immediately following the
+** end of a position-list. i.e. ( (*ppPoslist)[-1]==POS_END ). This function
+** moves *ppPoslist so that it instead points to the first byte of the
+** same position list.
+*/
+static void fts3ReversePoslist(char *pStart, char **ppPoslist){
+  char *p = &(*ppPoslist)[-2];
+  char c = 0;
+
+  while( p>pStart && (c=*p--)==0 );
+  while( p>pStart && (*p & 0x80) | c ){ 
+    c = *p--; 
+  }
+  if( p>pStart ){ p = &p[2]; }
+  while( *p++&0x80 );
+  *ppPoslist = p;
+}
+
+/*
+** Helper function used by the implementation of the overloaded snippet(),
+** offsets() and optimize() SQL functions.
+**
+** If the value passed as the third argument is a blob of size
+** sizeof(Fts3Cursor*), then the blob contents are copied to the 
+** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error
+** message is written to context pContext and SQLITE_ERROR returned. The
+** string passed via zFunc is used as part of the error message.
+*/
+static int fts3FunctionArg(
+  sqlite3_context *pContext,      /* SQL function call context */
+  const char *zFunc,              /* Function name */
+  sqlite3_value *pVal,            /* argv[0] passed to function */
+  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
+){
+  Fts3Cursor *pRet;
+  if( sqlite3_value_type(pVal)!=SQLITE_BLOB 
+   || sqlite3_value_bytes(pVal)!=sizeof(Fts3Cursor *)
+  ){
+    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
+    sqlite3_result_error(pContext, zErr, -1);
+    sqlite3_free(zErr);
+    return SQLITE_ERROR;
+  }
+  memcpy(&pRet, sqlite3_value_blob(pVal), sizeof(Fts3Cursor *));
+  *ppCsr = pRet;
+  return SQLITE_OK;
 }
 
 /*
 ** Implementation of the snippet() function for FTS3
 */
-static void snippetFunc(
-  sqlite3_context *pContext,
-  int argc,
-  sqlite3_value **argv
+static void fts3SnippetFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of apVal[] array */
+  sqlite3_value **apVal           /* Array of arguments */
 ){
-  fulltext_cursor *pCursor;
-  if( argc<1 ) return;
-  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to html_snippet",-1);
-  }else{
-    const char *zStart = "<b>";
-    const char *zEnd = "</b>";
-    const char *zEllipsis = "<b>...</b>";
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    if( argc>=2 ){
-      zStart = (const char*)sqlite3_value_text(argv[1]);
-      if( argc>=3 ){
-        zEnd = (const char*)sqlite3_value_text(argv[2]);
-        if( argc>=4 ){
-          zEllipsis = (const char*)sqlite3_value_text(argv[3]);
-        }
-      }
-    }
-    snippetAllOffsets(pCursor);
-    snippetText(pCursor, zStart, zEnd, zEllipsis);
-    sqlite3_result_text(pContext, pCursor->snippet.zSnippet,
-                        pCursor->snippet.nSnippet, SQLITE_STATIC);
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+  const char *zStart = "<b>";
+  const char *zEnd = "</b>";
+  const char *zEllipsis = "<b>...</b>";
+  int iCol = -1;
+  int nToken = 15;                /* Default number of tokens in snippet */
+
+  /* There must be at least one argument passed to this function (otherwise
+  ** the non-overloaded version would have been called instead of this one).
+  */
+  assert( nVal>=1 );
+
+  if( nVal>6 ){
+    sqlite3_result_error(pContext, 
+        "wrong number of arguments to function snippet()", -1);
+    return;
+  }
+  if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return;
+
+  switch( nVal ){
+    case 6: nToken = sqlite3_value_int(apVal[5]);
+    case 5: iCol = sqlite3_value_int(apVal[4]);
+    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
+    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
+    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
+  }
+  if( !zEllipsis || !zEnd || !zStart ){
+    sqlite3_result_error_nomem(pContext);
+  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
+    sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
   }
 }
 
 /*
 ** Implementation of the offsets() function for FTS3
 */
-static void snippetOffsetsFunc(
-  sqlite3_context *pContext,
-  int argc,
-  sqlite3_value **argv
+static void fts3OffsetsFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
 ){
-  fulltext_cursor *pCursor;
-  if( argc<1 ) return;
-  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to offsets",-1);
-  }else{
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    snippetAllOffsets(pCursor);
-    snippetOffsetText(&pCursor->snippet);
-    sqlite3_result_text(pContext,
-                        pCursor->snippet.zOffset, pCursor->snippet.nOffset,
-                        SQLITE_STATIC);
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+
+  UNUSED_PARAMETER(nVal);
+
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "offsets", apVal[0], &pCsr) ) return;
+  assert( pCsr );
+  if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
+    sqlite3Fts3Offsets(pContext, pCsr);
   }
 }
 
-/* OptLeavesReader is nearly identical to LeavesReader, except that
-** where LeavesReader is geared towards the merging of complete
-** segment levels (with exactly MERGE_COUNT segments), OptLeavesReader
-** is geared towards implementation of the optimize() function, and
-** can merge all segments simultaneously.  This version may be
-** somewhat less efficient than LeavesReader because it merges into an
-** accumulator rather than doing an N-way merge, but since segment
-** size grows exponentially (so segment count logrithmically) this is
-** probably not an immediate problem.
+/* 
+** Implementation of the special optimize() function for FTS3. This 
+** function merges all segments in the database to a single segment.
+** Example usage is:
+**
+**   SELECT optimize(t) FROM t LIMIT 1;
+**
+** where 't' is the name of an FTS3 table.
 */
-/* TODO(shess): Prove that assertion, or extend the merge code to
-** merge tree fashion (like the prefix-searching code does).
-*/
-/* TODO(shess): OptLeavesReader and LeavesReader could probably be
-** merged with little or no loss of performance for LeavesReader.  The
-** merged code would need to handle >MERGE_COUNT segments, and would
-** also need to be able to optionally optimize away deletes.
-*/
-typedef struct OptLeavesReader {
-  /* Segment number, to order readers by age. */
-  int segment;
-  LeavesReader reader;
-} OptLeavesReader;
-
-static int optLeavesReaderAtEnd(OptLeavesReader *pReader){
-  return leavesReaderAtEnd(&pReader->reader);
-}
-static int optLeavesReaderTermBytes(OptLeavesReader *pReader){
-  return leavesReaderTermBytes(&pReader->reader);
-}
-static const char *optLeavesReaderData(OptLeavesReader *pReader){
-  return leavesReaderData(&pReader->reader);
-}
-static int optLeavesReaderDataBytes(OptLeavesReader *pReader){
-  return leavesReaderDataBytes(&pReader->reader);
-}
-static const char *optLeavesReaderTerm(OptLeavesReader *pReader){
-  return leavesReaderTerm(&pReader->reader);
-}
-static int optLeavesReaderStep(fulltext_vtab *v, OptLeavesReader *pReader){
-  return leavesReaderStep(v, &pReader->reader);
-}
-static int optLeavesReaderTermCmp(OptLeavesReader *lr1, OptLeavesReader *lr2){
-  return leavesReaderTermCmp(&lr1->reader, &lr2->reader);
-}
-/* Order by term ascending, segment ascending (oldest to newest), with
-** exhausted readers to the end.
-*/
-static int optLeavesReaderCmp(OptLeavesReader *lr1, OptLeavesReader *lr2){
-  int c = optLeavesReaderTermCmp(lr1, lr2);
-  if( c!=0 ) return c;
-  return lr1->segment-lr2->segment;
-}
-/* Bubble pLr[0] to appropriate place in pLr[1..nLr-1].  Assumes that
-** pLr[1..nLr-1] is already sorted.
-*/
-static void optLeavesReaderReorder(OptLeavesReader *pLr, int nLr){
-  while( nLr>1 && optLeavesReaderCmp(pLr, pLr+1)>0 ){
-    OptLeavesReader tmp = pLr[0];
-    pLr[0] = pLr[1];
-    pLr[1] = tmp;
-    nLr--;
-    pLr++;
-  }
-}
-
-/* optimize() helper function.  Put the readers in order and iterate
-** through them, merging doclists for matching terms into pWriter.
-** Returns SQLITE_OK on success, or the SQLite error code which
-** prevented success.
-*/
-static int optimizeInternal(fulltext_vtab *v,
-                            OptLeavesReader *readers, int nReaders,
-                            LeafWriter *pWriter){
-  int i, rc = SQLITE_OK;
-  DataBuffer doclist, merged, tmp;
-
-  /* Order the readers. */
-  i = nReaders;
-  while( i-- > 0 ){
-    optLeavesReaderReorder(&readers[i], nReaders-i);
-  }
-
-  dataBufferInit(&doclist, LEAF_MAX);
-  dataBufferInit(&merged, LEAF_MAX);
-
-  /* Exhausted readers bubble to the end, so when the first reader is
-  ** at eof, all are at eof.
-  */
-  while( !optLeavesReaderAtEnd(&readers[0]) ){
-
-    /* Figure out how many readers share the next term. */
-    for(i=1; i<nReaders && !optLeavesReaderAtEnd(&readers[i]); i++){
-      if( 0!=optLeavesReaderTermCmp(&readers[0], &readers[i]) ) break;
-    }
-
-    /* Special-case for no merge. */
-    if( i==1 ){
-      /* Trim deletions from the doclist. */
-      dataBufferReset(&merged);
-      docListTrim(DL_DEFAULT,
-                  optLeavesReaderData(&readers[0]),
-                  optLeavesReaderDataBytes(&readers[0]),
-                  -1, DL_DEFAULT, &merged);
-    }else{
-      DLReader dlReaders[MERGE_COUNT];
-      int iReader, nReaders;
-
-      /* Prime the pipeline with the first reader's doclist.  After
-      ** one pass index 0 will reference the accumulated doclist.
-      */
-      dlrInit(&dlReaders[0], DL_DEFAULT,
-              optLeavesReaderData(&readers[0]),
-              optLeavesReaderDataBytes(&readers[0]));
-      iReader = 1;
-
-      assert( iReader<i );  /* Must execute the loop at least once. */
-      while( iReader<i ){
-        /* Merge 16 inputs per pass. */
-        for( nReaders=1; iReader<i && nReaders<MERGE_COUNT;
-             iReader++, nReaders++ ){
-          dlrInit(&dlReaders[nReaders], DL_DEFAULT,
-                  optLeavesReaderData(&readers[iReader]),
-                  optLeavesReaderDataBytes(&readers[iReader]));
-        }
-
-        /* Merge doclists and swap result into accumulator. */
-        dataBufferReset(&merged);
-        docListMerge(&merged, dlReaders, nReaders);
-        tmp = merged;
-        merged = doclist;
-        doclist = tmp;
-
-        while( nReaders-- > 0 ){
-          dlrDestroy(&dlReaders[nReaders]);
-        }
-
-        /* Accumulated doclist to reader 0 for next pass. */
-        dlrInit(&dlReaders[0], DL_DEFAULT, doclist.pData, doclist.nData);
-      }
-
-      /* Destroy reader that was left in the pipeline. */
-      dlrDestroy(&dlReaders[0]);
-
-      /* Trim deletions from the doclist. */
-      dataBufferReset(&merged);
-      docListTrim(DL_DEFAULT, doclist.pData, doclist.nData,
-                  -1, DL_DEFAULT, &merged);
-    }
-
-    /* Only pass doclists with hits (skip if all hits deleted). */
-    if( merged.nData>0 ){
-      rc = leafWriterStep(v, pWriter,
-                          optLeavesReaderTerm(&readers[0]),
-                          optLeavesReaderTermBytes(&readers[0]),
-                          merged.pData, merged.nData);
-      if( rc!=SQLITE_OK ) goto err;
-    }
-
-    /* Step merged readers to next term and reorder. */
-    while( i-- > 0 ){
-      rc = optLeavesReaderStep(v, &readers[i]);
-      if( rc!=SQLITE_OK ) goto err;
-
-      optLeavesReaderReorder(&readers[i], nReaders-i);
-    }
-  }
-
- err:
-  dataBufferDestroy(&doclist);
-  dataBufferDestroy(&merged);
-  return rc;
-}
-
-/* Implement optimize() function for FTS3.  optimize(t) merges all
-** segments in the fts index into a single segment.  't' is the magic
-** table-named column.
-*/
-static void optimizeFunc(sqlite3_context *pContext,
-                         int argc, sqlite3_value **argv){
-  fulltext_cursor *pCursor;
-  if( argc>1 ){
-    sqlite3_result_error(pContext, "excess arguments to optimize()",-1);
-  }else if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-            sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to optimize",-1);
-  }else{
-    fulltext_vtab *v;
-    int i, rc, iMaxLevel;
-    OptLeavesReader *readers;
-    int nReaders;
-    LeafWriter writer;
-    sqlite3_stmt *s;
-
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    v = cursor_vtab(pCursor);
-
-    /* Flush any buffered updates before optimizing. */
-    rc = flushPendingTerms(v);
-    if( rc!=SQLITE_OK ) goto err;
-
-    rc = segdir_count(v, &nReaders, &iMaxLevel);
-    if( rc!=SQLITE_OK ) goto err;
-    if( nReaders==0 || nReaders==1 ){
-      sqlite3_result_text(pContext, "Index already optimal", -1,
-                          SQLITE_STATIC);
-      return;
-    }
-
-    rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
-    if( rc!=SQLITE_OK ) goto err;
-
-    readers = sqlite3_malloc(nReaders*sizeof(readers[0]));
-    if( readers==NULL ) goto err;
-
-    /* Note that there will already be a segment at this position
-    ** until we call segdir_delete() on iMaxLevel.
-    */
-    leafWriterInit(iMaxLevel, 0, &writer);
-
-    i = 0;
-    while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-      sqlite_int64 iStart = sqlite3_column_int64(s, 0);
-      sqlite_int64 iEnd = sqlite3_column_int64(s, 1);
-      const char *pRootData = sqlite3_column_blob(s, 2);
-      int nRootData = sqlite3_column_bytes(s, 2);
-
-      assert( i<nReaders );
-      rc = leavesReaderInit(v, -1, iStart, iEnd, pRootData, nRootData,
-                            &readers[i].reader);
-      if( rc!=SQLITE_OK ) break;
-
-      readers[i].segment = i;
-      i++;
-    }
-
-    /* If we managed to succesfully read them all, optimize them. */
-    if( rc==SQLITE_DONE ){
-      assert( i==nReaders );
-      rc = optimizeInternal(v, readers, nReaders, &writer);
-    }
-
-    while( i-- > 0 ){
-      leavesReaderDestroy(&readers[i].reader);
-    }
-    sqlite3_free(readers);
-
-    /* If we've successfully gotten to here, delete the old segments
-    ** and flush the interior structure of the new segment.
-    */
-    if( rc==SQLITE_OK ){
-      for( i=0; i<=iMaxLevel; i++ ){
-        rc = segdir_delete(v, i);
-        if( rc!=SQLITE_OK ) break;
-      }
-
-      if( rc==SQLITE_OK ) rc = leafWriterFinalize(v, &writer);
-    }
-
-    leafWriterDestroy(&writer);
-
-    if( rc!=SQLITE_OK ) goto err;
-
-    sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
-    return;
-
-    /* TODO(shess): Error-handling needs to be improved along the
-    ** lines of the dump_ functions.
-    */
- err:
-    {
-      char buf[512];
-      sqlite3_snprintf(sizeof(buf), buf, "Error in optimize: %s",
-                       sqlite3_errmsg(sqlite3_context_db_handle(pContext)));
-      sqlite3_result_error(pContext, buf, -1);
-    }
-  }
-}
-
-#ifdef SQLITE_TEST
-/* Generate an error of the form "<prefix>: <msg>".  If msg is NULL,
-** pull the error from the context's db handle.
-*/
-static void generateError(sqlite3_context *pContext,
-                          const char *prefix, const char *msg){
-  char buf[512];
-  if( msg==NULL ) msg = sqlite3_errmsg(sqlite3_context_db_handle(pContext));
-  sqlite3_snprintf(sizeof(buf), buf, "%s: %s", prefix, msg);
-  sqlite3_result_error(pContext, buf, -1);
-}
-
-/* Helper function to collect the set of terms in the segment into
-** pTerms.  The segment is defined by the leaf nodes between
-** iStartBlockid and iEndBlockid, inclusive, or by the contents of
-** pRootData if iStartBlockid is 0 (in which case the entire segment
-** fit in a leaf).
-*/
-static int collectSegmentTerms(fulltext_vtab *v, sqlite3_stmt *s,
-                               fts3Hash *pTerms){
-  const sqlite_int64 iStartBlockid = sqlite3_column_int64(s, 0);
-  const sqlite_int64 iEndBlockid = sqlite3_column_int64(s, 1);
-  const char *pRootData = sqlite3_column_blob(s, 2);
-  const int nRootData = sqlite3_column_bytes(s, 2);
-  LeavesReader reader;
-  int rc = leavesReaderInit(v, 0, iStartBlockid, iEndBlockid,
-                            pRootData, nRootData, &reader);
-  if( rc!=SQLITE_OK ) return rc;
-
-  while( rc==SQLITE_OK && !leavesReaderAtEnd(&reader) ){
-    const char *pTerm = leavesReaderTerm(&reader);
-    const int nTerm = leavesReaderTermBytes(&reader);
-    void *oldValue = sqlite3Fts3HashFind(pTerms, pTerm, nTerm);
-    void *newValue = (void *)((char *)oldValue+1);
-
-    /* From the comment before sqlite3Fts3HashInsert in fts3_hash.c,
-    ** the data value passed is returned in case of malloc failure.
-    */
-    if( newValue==sqlite3Fts3HashInsert(pTerms, pTerm, nTerm, newValue) ){
-      rc = SQLITE_NOMEM;
-    }else{
-      rc = leavesReaderStep(v, &reader);
-    }
-  }
-
-  leavesReaderDestroy(&reader);
-  return rc;
-}
-
-/* Helper function to build the result string for dump_terms(). */
-static int generateTermsResult(sqlite3_context *pContext, fts3Hash *pTerms){
-  int iTerm, nTerms, nResultBytes, iByte;
-  char *result;
-  TermData *pData;
-  fts3HashElem *e;
-
-  /* Iterate pTerms to generate an array of terms in pData for
-  ** sorting.
-  */
-  nTerms = fts3HashCount(pTerms);
-  assert( nTerms>0 );
-  pData = sqlite3_malloc(nTerms*sizeof(TermData));
-  if( pData==NULL ) return SQLITE_NOMEM;
-
-  nResultBytes = 0;
-  for(iTerm = 0, e = fts3HashFirst(pTerms); e; iTerm++, e = fts3HashNext(e)){
-    nResultBytes += fts3HashKeysize(e)+1;   /* Term plus trailing space */
-    assert( iTerm<nTerms );
-    pData[iTerm].pTerm = fts3HashKey(e);
-    pData[iTerm].nTerm = fts3HashKeysize(e);
-    pData[iTerm].pCollector = fts3HashData(e);  /* unused */
-  }
-  assert( iTerm==nTerms );
-
-  assert( nResultBytes>0 );   /* nTerms>0, nResultsBytes must be, too. */
-  result = sqlite3_malloc(nResultBytes);
-  if( result==NULL ){
-    sqlite3_free(pData);
-    return SQLITE_NOMEM;
-  }
-
-  if( nTerms>1 ) qsort(pData, nTerms, sizeof(*pData), termDataCmp);
-
-  /* Read the terms in order to build the result. */
-  iByte = 0;
-  for(iTerm=0; iTerm<nTerms; ++iTerm){
-    memcpy(result+iByte, pData[iTerm].pTerm, pData[iTerm].nTerm);
-    iByte += pData[iTerm].nTerm;
-    result[iByte++] = ' ';
-  }
-  assert( iByte==nResultBytes );
-  assert( result[nResultBytes-1]==' ' );
-  result[nResultBytes-1] = '\0';
-
-  /* Passes away ownership of result. */
-  sqlite3_result_text(pContext, result, nResultBytes-1, sqlite3_free);
-  sqlite3_free(pData);
-  return SQLITE_OK;
-}
-
-/* Implements dump_terms() for use in inspecting the fts3 index from
-** tests.  TEXT result containing the ordered list of terms joined by
-** spaces.  dump_terms(t, level, idx) dumps the terms for the segment
-** specified by level, idx (in %_segdir), while dump_terms(t) dumps
-** all terms in the index.  In both cases t is the fts table's magic
-** table-named column.
-*/
-static void dumpTermsFunc(
-  sqlite3_context *pContext,
-  int argc, sqlite3_value **argv
+static void fts3OptimizeFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
 ){
-  fulltext_cursor *pCursor;
-  if( argc!=3 && argc!=1 ){
-    generateError(pContext, "dump_terms", "incorrect arguments");
-  }else if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-            sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    generateError(pContext, "dump_terms", "illegal first argument");
-  }else{
-    fulltext_vtab *v;
-    fts3Hash terms;
-    sqlite3_stmt *s = NULL;
-    int rc;
+  int rc;                         /* Return code */
+  Fts3Table *p;                   /* Virtual table handle */
+  Fts3Cursor *pCursor;            /* Cursor handle passed through apVal[0] */
 
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    v = cursor_vtab(pCursor);
+  UNUSED_PARAMETER(nVal);
 
-    /* If passed only the cursor column, get all segments.  Otherwise
-    ** get the segment described by the following two arguments.
-    */
-    if( argc==1 ){
-      rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
-    }else{
-      rc = sql_get_statement(v, SEGDIR_SELECT_SEGMENT_STMT, &s);
-      if( rc==SQLITE_OK ){
-        rc = sqlite3_bind_int(s, 1, sqlite3_value_int(argv[1]));
-        if( rc==SQLITE_OK ){
-          rc = sqlite3_bind_int(s, 2, sqlite3_value_int(argv[2]));
-        }
-      }
-    }
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "optimize", apVal[0], &pCursor) ) return;
+  p = (Fts3Table *)pCursor->base.pVtab;
+  assert( p );
 
-    if( rc!=SQLITE_OK ){
-      generateError(pContext, "dump_terms", NULL);
-      return;
-    }
+  rc = sqlite3Fts3Optimize(p);
 
-    /* Collect the terms for each segment. */
-    sqlite3Fts3HashInit(&terms, FTS3_HASH_STRING, 1);
-    while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-      rc = collectSegmentTerms(v, s, &terms);
-      if( rc!=SQLITE_OK ) break;
-    }
-
-    if( rc!=SQLITE_DONE ){
-      sqlite3_reset(s);
-      generateError(pContext, "dump_terms", NULL);
-    }else{
-      const int nTerms = fts3HashCount(&terms);
-      if( nTerms>0 ){
-        rc = generateTermsResult(pContext, &terms);
-        if( rc==SQLITE_NOMEM ){
-          generateError(pContext, "dump_terms", "out of memory");
-        }else{
-          assert( rc==SQLITE_OK );
-        }
-      }else if( argc==3 ){
-        /* The specific segment asked for could not be found. */
-        generateError(pContext, "dump_terms", "segment not found");
-      }else{
-        /* No segments found. */
-        /* TODO(shess): It should be impossible to reach this.  This
-        ** case can only happen for an empty table, in which case
-        ** SQLite has no rows to call this function on.
-        */
-        sqlite3_result_null(pContext);
-      }
-    }
-    sqlite3Fts3HashClear(&terms);
+  switch( rc ){
+    case SQLITE_OK:
+      sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
+      break;
+    case SQLITE_DONE:
+      sqlite3_result_text(pContext, "Index already optimal", -1, SQLITE_STATIC);
+      break;
+    default:
+      sqlite3_result_error_code(pContext, rc);
+      break;
   }
 }
 
-/* Expand the DL_DEFAULT doclist in pData into a text result in
-** pContext.
+/*
+** Implementation of the matchinfo() function for FTS3
 */
-static void createDoclistResult(sqlite3_context *pContext,
-                                const char *pData, int nData){
-  DataBuffer dump;
-  DLReader dlReader;
-
-  assert( pData!=NULL && nData>0 );
-
-  dataBufferInit(&dump, 0);
-  dlrInit(&dlReader, DL_DEFAULT, pData, nData);
-  for( ; !dlrAtEnd(&dlReader); dlrStep(&dlReader) ){
-    char buf[256];
-    PLReader plReader;
-
-    plrInit(&plReader, &dlReader);
-    if( DL_DEFAULT==DL_DOCIDS || plrAtEnd(&plReader) ){
-      sqlite3_snprintf(sizeof(buf), buf, "[%lld] ", dlrDocid(&dlReader));
-      dataBufferAppend(&dump, buf, strlen(buf));
-    }else{
-      int iColumn = plrColumn(&plReader);
-
-      sqlite3_snprintf(sizeof(buf), buf, "[%lld %d[",
-                       dlrDocid(&dlReader), iColumn);
-      dataBufferAppend(&dump, buf, strlen(buf));
-
-      for( ; !plrAtEnd(&plReader); plrStep(&plReader) ){
-        if( plrColumn(&plReader)!=iColumn ){
-          iColumn = plrColumn(&plReader);
-          sqlite3_snprintf(sizeof(buf), buf, "] %d[", iColumn);
-          assert( dump.nData>0 );
-          dump.nData--;                     /* Overwrite trailing space. */
-          assert( dump.pData[dump.nData]==' ');
-          dataBufferAppend(&dump, buf, strlen(buf));
-        }
-        if( DL_DEFAULT==DL_POSITIONS_OFFSETS ){
-          sqlite3_snprintf(sizeof(buf), buf, "%d,%d,%d ",
-                           plrPosition(&plReader),
-                           plrStartOffset(&plReader), plrEndOffset(&plReader));
-        }else if( DL_DEFAULT==DL_POSITIONS ){
-          sqlite3_snprintf(sizeof(buf), buf, "%d ", plrPosition(&plReader));
-        }else{
-          assert( NULL=="Unhandled DL_DEFAULT value");
-        }
-        dataBufferAppend(&dump, buf, strlen(buf));
-      }
-      plrDestroy(&plReader);
-
-      assert( dump.nData>0 );
-      dump.nData--;                     /* Overwrite trailing space. */
-      assert( dump.pData[dump.nData]==' ');
-      dataBufferAppend(&dump, "]] ", 3);
-    }
-  }
-  dlrDestroy(&dlReader);
-
-  assert( dump.nData>0 );
-  dump.nData--;                     /* Overwrite trailing space. */
-  assert( dump.pData[dump.nData]==' ');
-  dump.pData[dump.nData] = '\0';
-  assert( dump.nData>0 );
-
-  /* Passes ownership of dump's buffer to pContext. */
-  sqlite3_result_text(pContext, dump.pData, dump.nData, sqlite3_free);
-  dump.pData = NULL;
-  dump.nData = dump.nCapacity = 0;
-}
-
-/* Implements dump_doclist() for use in inspecting the fts3 index from
-** tests.  TEXT result containing a string representation of the
-** doclist for the indicated term.  dump_doclist(t, term, level, idx)
-** dumps the doclist for term from the segment specified by level, idx
-** (in %_segdir), while dump_doclist(t, term) dumps the logical
-** doclist for the term across all segments.  The per-segment doclist
-** can contain deletions, while the full-index doclist will not
-** (deletions are omitted).
-**
-** Result formats differ with the setting of DL_DEFAULTS.  Examples:
-**
-** DL_DOCIDS: [1] [3] [7]
-** DL_POSITIONS: [1 0[0 4] 1[17]] [3 1[5]]
-** DL_POSITIONS_OFFSETS: [1 0[0,0,3 4,23,26] 1[17,102,105]] [3 1[5,20,23]]
-**
-** In each case the number after the outer '[' is the docid.  In the
-** latter two cases, the number before the inner '[' is the column
-** associated with the values within.  For DL_POSITIONS the numbers
-** within are the positions, for DL_POSITIONS_OFFSETS they are the
-** position, the start offset, and the end offset.
-*/
-static void dumpDoclistFunc(
-  sqlite3_context *pContext,
-  int argc, sqlite3_value **argv
+static void fts3MatchinfoFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
 ){
-  fulltext_cursor *pCursor;
-  if( argc!=2 && argc!=4 ){
-    generateError(pContext, "dump_doclist", "incorrect arguments");
-  }else if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-            sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    generateError(pContext, "dump_doclist", "illegal first argument");
-  }else if( sqlite3_value_text(argv[1])==NULL ||
-            sqlite3_value_text(argv[1])[0]=='\0' ){
-    generateError(pContext, "dump_doclist", "empty second argument");
-  }else{
-    const char *pTerm = (const char *)sqlite3_value_text(argv[1]);
-    const int nTerm = strlen(pTerm);
-    fulltext_vtab *v;
-    int rc;
-    DataBuffer doclist;
-
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    v = cursor_vtab(pCursor);
-
-    dataBufferInit(&doclist, 0);
-
-    /* termSelect() yields the same logical doclist that queries are
-    ** run against.
-    */
-    if( argc==2 ){
-      rc = termSelect(v, v->nColumn, pTerm, nTerm, 0, DL_DEFAULT, &doclist);
-    }else{
-      sqlite3_stmt *s = NULL;
-
-      /* Get our specific segment's information. */
-      rc = sql_get_statement(v, SEGDIR_SELECT_SEGMENT_STMT, &s);
-      if( rc==SQLITE_OK ){
-        rc = sqlite3_bind_int(s, 1, sqlite3_value_int(argv[2]));
-        if( rc==SQLITE_OK ){
-          rc = sqlite3_bind_int(s, 2, sqlite3_value_int(argv[3]));
-        }
-      }
-
-      if( rc==SQLITE_OK ){
-        rc = sqlite3_step(s);
-
-        if( rc==SQLITE_DONE ){
-          dataBufferDestroy(&doclist);
-          generateError(pContext, "dump_doclist", "segment not found");
-          return;
-        }
-
-        /* Found a segment, load it into doclist. */
-        if( rc==SQLITE_ROW ){
-          const sqlite_int64 iLeavesEnd = sqlite3_column_int64(s, 1);
-          const char *pData = sqlite3_column_blob(s, 2);
-          const int nData = sqlite3_column_bytes(s, 2);
-
-          /* loadSegment() is used by termSelect() to load each
-          ** segment's data.
-          */
-          rc = loadSegment(v, pData, nData, iLeavesEnd, pTerm, nTerm, 0,
-                           &doclist);
-          if( rc==SQLITE_OK ){
-            rc = sqlite3_step(s);
-
-            /* Should not have more than one matching segment. */
-            if( rc!=SQLITE_DONE ){
-              sqlite3_reset(s);
-              dataBufferDestroy(&doclist);
-              generateError(pContext, "dump_doclist", "invalid segdir");
-              return;
-            }
-            rc = SQLITE_OK;
-          }
-        }
-      }
-
-      sqlite3_reset(s);
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+  assert( nVal==1 || nVal==2 );
+  if( SQLITE_OK==fts3FunctionArg(pContext, "matchinfo", apVal[0], &pCsr) ){
+    const char *zArg = 0;
+    if( nVal>1 ){
+      zArg = (const char *)sqlite3_value_text(apVal[1]);
     }
-
-    if( rc==SQLITE_OK ){
-      if( doclist.nData>0 ){
-        createDoclistResult(pContext, doclist.pData, doclist.nData);
-      }else{
-        /* TODO(shess): This can happen if the term is not present, or
-        ** if all instances of the term have been deleted and this is
-        ** an all-index dump.  It may be interesting to distinguish
-        ** these cases.
-        */
-        sqlite3_result_text(pContext, "", 0, SQLITE_STATIC);
-      }
-    }else if( rc==SQLITE_NOMEM ){
-      /* Handle out-of-memory cases specially because if they are
-      ** generated in fts3 code they may not be reflected in the db
-      ** handle.
-      */
-      /* TODO(shess): Handle this more comprehensively.
-      ** sqlite3ErrStr() has what I need, but is internal.
-      */
-      generateError(pContext, "dump_doclist", "out of memory");
-    }else{
-      generateError(pContext, "dump_doclist", NULL);
-    }
-
-    dataBufferDestroy(&doclist);
+    sqlite3Fts3Matchinfo(pContext, pCsr, zArg);
   }
 }
-#endif
 
 /*
 ** This routine implements the xFindFunction method for the FTS3
 ** virtual table.
 */
-static int fulltextFindFunction(
-  sqlite3_vtab *pVtab,
-  int nArg,
-  const char *zName,
-  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
-  void **ppArg
+static int fts3FindFunctionMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* Unused */
 ){
-  if( strcmp(zName,"snippet")==0 ){
-    *pxFunc = snippetFunc;
-    return 1;
-  }else if( strcmp(zName,"offsets")==0 ){
-    *pxFunc = snippetOffsetsFunc;
-    return 1;
-  }else if( strcmp(zName,"optimize")==0 ){
-    *pxFunc = optimizeFunc;
-    return 1;
-#ifdef SQLITE_TEST
-    /* NOTE(shess): These functions are present only for testing
-    ** purposes.  No particular effort is made to optimize their
-    ** execution or how they build their results.
-    */
-  }else if( strcmp(zName,"dump_terms")==0 ){
-    /* fprintf(stderr, "Found dump_terms\n"); */
-    *pxFunc = dumpTermsFunc;
-    return 1;
-  }else if( strcmp(zName,"dump_doclist")==0 ){
-    /* fprintf(stderr, "Found dump_doclist\n"); */
-    *pxFunc = dumpDoclistFunc;
-    return 1;
-#endif
+  struct Overloaded {
+    const char *zName;
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } aOverload[] = {
+    { "snippet", fts3SnippetFunc },
+    { "offsets", fts3OffsetsFunc },
+    { "optimize", fts3OptimizeFunc },
+    { "matchinfo", fts3MatchinfoFunc },
+  };
+  int i;                          /* Iterator variable */
+
+  UNUSED_PARAMETER(pVtab);
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(ppArg);
+
+  for(i=0; i<SizeofArray(aOverload); i++){
+    if( strcmp(zName, aOverload[i].zName)==0 ){
+      *pxFunc = aOverload[i].xFunc;
+      return 1;
+    }
   }
+
+  /* No function of the specified name was found. Return 0. */
   return 0;
 }
 
 /*
-** Rename an fts3 table.
+** Implementation of FTS3 xRename method. Rename an fts3 table.
 */
-static int fulltextRename(
-  sqlite3_vtab *pVtab,
-  const char *zName
+static int fts3RenameMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  const char *zName               /* New name of table */
 ){
-  fulltext_vtab *p = (fulltext_vtab *)pVtab;
-  int rc = SQLITE_NOMEM;
-  char *zSql = sqlite3_mprintf(
-    "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';"
-    "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';"
-    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';"
-    , p->zDb, p->zName, zName 
-    , p->zDb, p->zName, zName 
-    , p->zDb, p->zName, zName
+  Fts3Table *p = (Fts3Table *)pVtab;
+  sqlite3 *db = p->db;            /* Database connection */
+  int rc;                         /* Return Code */
+
+  /* As it happens, the pending terms table is always empty here. This is
+  ** because an "ALTER TABLE RENAME TABLE" statement inside a transaction 
+  ** always opens a savepoint transaction. And the xSavepoint() method 
+  ** flushes the pending terms table. But leave the (no-op) call to
+  ** PendingTermsFlush() in in case that changes.
+  */
+  assert( p->nPendingData==0 );
+  rc = sqlite3Fts3PendingTermsFlush(p);
+
+  if( p->zContentTbl==0 ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';",
+      p->zDb, p->zName, zName
+    );
+  }
+
+  if( p->bHasDocsize ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_docsize'  RENAME TO '%q_docsize';",
+      p->zDb, p->zName, zName
+    );
+  }
+  if( p->bHasStat ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_stat'  RENAME TO '%q_stat';",
+      p->zDb, p->zName, zName
+    );
+  }
+  fts3DbExec(&rc, db,
+    "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';",
+    p->zDb, p->zName, zName
   );
-  if( zSql ){
-    rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
-    sqlite3_free(zSql);
+  fts3DbExec(&rc, db,
+    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';",
+    p->zDb, p->zName, zName
+  );
+  return rc;
+}
+
+/*
+** The xSavepoint() method.
+**
+** Flush the contents of the pending-terms table to disk.
+*/
+static int fts3SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  int rc = SQLITE_OK;
+  UNUSED_PARAMETER(iSavepoint);
+  assert( ((Fts3Table *)pVtab)->inTransaction );
+  assert( ((Fts3Table *)pVtab)->mxSavepoint < iSavepoint );
+  TESTONLY( ((Fts3Table *)pVtab)->mxSavepoint = iSavepoint );
+  if( ((Fts3Table *)pVtab)->bIgnoreSavepoint==0 ){
+    rc = fts3SyncMethod(pVtab);
   }
   return rc;
 }
 
+/*
+** The xRelease() method.
+**
+** This is a no-op.
+*/
+static int fts3ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
+  UNUSED_PARAMETER(iSavepoint);
+  UNUSED_PARAMETER(pVtab);
+  assert( p->inTransaction );
+  assert( p->mxSavepoint >= iSavepoint );
+  TESTONLY( p->mxSavepoint = iSavepoint-1 );
+  return SQLITE_OK;
+}
+
+/*
+** The xRollbackTo() method.
+**
+** Discard the contents of the pending terms table.
+*/
+static int fts3RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  UNUSED_PARAMETER(iSavepoint);
+  assert( p->inTransaction );
+  assert( p->mxSavepoint >= iSavepoint );
+  TESTONLY( p->mxSavepoint = iSavepoint );
+  sqlite3Fts3PendingTermsClear(p);
+  return SQLITE_OK;
+}
+
 static const sqlite3_module fts3Module = {
-  /* iVersion      */ 0,
-  /* xCreate       */ fulltextCreate,
-  /* xConnect      */ fulltextConnect,
-  /* xBestIndex    */ fulltextBestIndex,
-  /* xDisconnect   */ fulltextDisconnect,
-  /* xDestroy      */ fulltextDestroy,
-  /* xOpen         */ fulltextOpen,
-  /* xClose        */ fulltextClose,
-  /* xFilter       */ fulltextFilter,
-  /* xNext         */ fulltextNext,
-  /* xEof          */ fulltextEof,
-  /* xColumn       */ fulltextColumn,
-  /* xRowid        */ fulltextRowid,
-  /* xUpdate       */ fulltextUpdate,
-  /* xBegin        */ fulltextBegin,
-  /* xSync         */ fulltextSync,
-  /* xCommit       */ fulltextCommit,
-  /* xRollback     */ fulltextRollback,
-  /* xFindFunction */ fulltextFindFunction,
-  /* xRename */       fulltextRename,
+  /* iVersion      */ 2,
+  /* xCreate       */ fts3CreateMethod,
+  /* xConnect      */ fts3ConnectMethod,
+  /* xBestIndex    */ fts3BestIndexMethod,
+  /* xDisconnect   */ fts3DisconnectMethod,
+  /* xDestroy      */ fts3DestroyMethod,
+  /* xOpen         */ fts3OpenMethod,
+  /* xClose        */ fts3CloseMethod,
+  /* xFilter       */ fts3FilterMethod,
+  /* xNext         */ fts3NextMethod,
+  /* xEof          */ fts3EofMethod,
+  /* xColumn       */ fts3ColumnMethod,
+  /* xRowid        */ fts3RowidMethod,
+  /* xUpdate       */ fts3UpdateMethod,
+  /* xBegin        */ fts3BeginMethod,
+  /* xSync         */ fts3SyncMethod,
+  /* xCommit       */ fts3CommitMethod,
+  /* xRollback     */ fts3RollbackMethod,
+  /* xFindFunction */ fts3FindFunctionMethod,
+  /* xRename */       fts3RenameMethod,
+  /* xSavepoint    */ fts3SavepointMethod,
+  /* xRelease      */ fts3ReleaseMethod,
+  /* xRollbackTo   */ fts3RollbackToMethod,
 };
 
+/*
+** This function is registered as the module destructor (called when an
+** FTS3 enabled database connection is closed). It frees the memory
+** allocated for the tokenizer hash table.
+*/
 static void hashDestroy(void *p){
-  fts3Hash *pHash = (fts3Hash *)p;
+  Fts3Hash *pHash = (Fts3Hash *)p;
   sqlite3Fts3HashClear(pHash);
   sqlite3_free(pHash);
 }
 
 /*
-** The fts3 built-in tokenizers - "simple" and "porter" - are implemented
-** in files fts3_tokenizer1.c and fts3_porter.c respectively. The following
-** two forward declarations are for functions declared in these files
-** used to retrieve the respective implementations.
+** The fts3 built-in tokenizers - "simple", "porter" and "icu"- are 
+** implemented in files fts3_tokenizer1.c, fts3_porter.c and fts3_icu.c
+** respectively. The following three forward declarations are for functions
+** declared in these files used to retrieve the respective implementations.
 **
 ** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
-** to by the argument to point a the "simple" tokenizer implementation.
-** Function ...PorterTokenizerModule() sets *pModule to point to the
-** porter tokenizer/stemmer implementation.
+** to by the argument to point to the "simple" tokenizer implementation.
+** And so on.
 */
 SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
 SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+#ifdef SQLITE_ENABLE_FTS4_UNICODE61
+SQLITE_PRIVATE void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const**ppModule);
+#endif
+#ifdef SQLITE_ENABLE_ICU
 SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
-
-SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, fts3Hash *, const char *);
+#endif
 
 /*
 ** Initialise the fts3 extension. If this extension is built as part
@@ -96706,19 +119513,35 @@ SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, fts3Hash *, const char *)
 */
 SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
   int rc = SQLITE_OK;
-  fts3Hash *pHash = 0;
+  Fts3Hash *pHash = 0;
   const sqlite3_tokenizer_module *pSimple = 0;
   const sqlite3_tokenizer_module *pPorter = 0;
-  const sqlite3_tokenizer_module *pIcu = 0;
+#ifdef SQLITE_ENABLE_FTS4_UNICODE61
+  const sqlite3_tokenizer_module *pUnicode = 0;
+#endif
 
-  sqlite3Fts3SimpleTokenizerModule(&pSimple);
-  sqlite3Fts3PorterTokenizerModule(&pPorter);
 #ifdef SQLITE_ENABLE_ICU
+  const sqlite3_tokenizer_module *pIcu = 0;
   sqlite3Fts3IcuTokenizerModule(&pIcu);
 #endif
 
+#ifdef SQLITE_ENABLE_FTS4_UNICODE61
+  sqlite3Fts3UnicodeTokenizer(&pUnicode);
+#endif
+
+#ifdef SQLITE_TEST
+  rc = sqlite3Fts3InitTerm(db);
+  if( rc!=SQLITE_OK ) return rc;
+#endif
+
+  rc = sqlite3Fts3InitAux(db);
+  if( rc!=SQLITE_OK ) return rc;
+
+  sqlite3Fts3SimpleTokenizerModule(&pSimple);
+  sqlite3Fts3PorterTokenizerModule(&pPorter);
+
   /* Allocate and initialise the hash-table used to store tokenizers. */
-  pHash = sqlite3_malloc(sizeof(fts3Hash));
+  pHash = sqlite3_malloc(sizeof(Fts3Hash));
   if( !pHash ){
     rc = SQLITE_NOMEM;
   }else{
@@ -96729,14 +119552,22 @@ SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
   if( rc==SQLITE_OK ){
     if( sqlite3Fts3HashInsert(pHash, "simple", 7, (void *)pSimple)
      || sqlite3Fts3HashInsert(pHash, "porter", 7, (void *)pPorter) 
+
+#ifdef SQLITE_ENABLE_FTS4_UNICODE61
+     || sqlite3Fts3HashInsert(pHash, "unicode61", 10, (void *)pUnicode) 
+#endif
+#ifdef SQLITE_ENABLE_ICU
      || (pIcu && sqlite3Fts3HashInsert(pHash, "icu", 4, (void *)pIcu))
+#endif
     ){
       rc = SQLITE_NOMEM;
     }
   }
 
 #ifdef SQLITE_TEST
-  sqlite3Fts3ExprInitTestInterface(db);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3ExprInitTestInterface(db);
+  }
 #endif
 
   /* Create the virtual table wrapper around the hash-table and overload 
@@ -96746,19 +119577,23 @@ SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
   if( SQLITE_OK==rc 
    && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
    && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", -1))
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", -1))
-#ifdef SQLITE_TEST
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_terms", -1))
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_doclist", -1))
-#endif
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 2))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
   ){
-    return sqlite3_create_module_v2(
+    rc = sqlite3_create_module_v2(
         db, "fts3", &fts3Module, (void *)pHash, hashDestroy
     );
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_module_v2(
+          db, "fts4", &fts3Module, (void *)pHash, 0
+      );
+    }
+    return rc;
   }
 
-  /* An error has occured. Delete the hash table and return the error code. */
+  /* An error has occurred. Delete the hash table and return the error code. */
   assert( rc!=SQLITE_OK );
   if( pHash ){
     sqlite3Fts3HashClear(pHash);
@@ -96767,7 +119602,1681 @@ SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
   return rc;
 }
 
+/*
+** Allocate an Fts3MultiSegReader for each token in the expression headed
+** by pExpr. 
+**
+** An Fts3SegReader object is a cursor that can seek or scan a range of
+** entries within a single segment b-tree. An Fts3MultiSegReader uses multiple
+** Fts3SegReader objects internally to provide an interface to seek or scan
+** within the union of all segments of a b-tree. Hence the name.
+**
+** If the allocated Fts3MultiSegReader just seeks to a single entry in a
+** segment b-tree (if the term is not a prefix or it is a prefix for which
+** there exists prefix b-tree of the right length) then it may be traversed
+** and merged incrementally. Otherwise, it has to be merged into an in-memory 
+** doclist and then traversed.
+*/
+static void fts3EvalAllocateReaders(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Allocate readers for this expression */
+  int *pnToken,                   /* OUT: Total number of tokens in phrase. */
+  int *pnOr,                      /* OUT: Total number of OR nodes in expr. */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( pExpr && SQLITE_OK==*pRc ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      int i;
+      int nToken = pExpr->pPhrase->nToken;
+      *pnToken += nToken;
+      for(i=0; i<nToken; i++){
+        Fts3PhraseToken *pToken = &pExpr->pPhrase->aToken[i];
+        int rc = fts3TermSegReaderCursor(pCsr, 
+            pToken->z, pToken->n, pToken->isPrefix, &pToken->pSegcsr
+        );
+        if( rc!=SQLITE_OK ){
+          *pRc = rc;
+          return;
+        }
+      }
+      assert( pExpr->pPhrase->iDoclistToken==0 );
+      pExpr->pPhrase->iDoclistToken = -1;
+    }else{
+      *pnOr += (pExpr->eType==FTSQUERY_OR);
+      fts3EvalAllocateReaders(pCsr, pExpr->pLeft, pnToken, pnOr, pRc);
+      fts3EvalAllocateReaders(pCsr, pExpr->pRight, pnToken, pnOr, pRc);
+    }
+  }
+}
+
+/*
+** Arguments pList/nList contain the doclist for token iToken of phrase p.
+** It is merged into the main doclist stored in p->doclist.aAll/nAll.
+**
+** This function assumes that pList points to a buffer allocated using
+** sqlite3_malloc(). This function takes responsibility for eventually
+** freeing the buffer.
+*/
+static void fts3EvalPhraseMergeToken(
+  Fts3Table *pTab,                /* FTS Table pointer */
+  Fts3Phrase *p,                  /* Phrase to merge pList/nList into */
+  int iToken,                     /* Token pList/nList corresponds to */
+  char *pList,                    /* Pointer to doclist */
+  int nList                       /* Number of bytes in pList */
+){
+  assert( iToken!=p->iDoclistToken );
+
+  if( pList==0 ){
+    sqlite3_free(p->doclist.aAll);
+    p->doclist.aAll = 0;
+    p->doclist.nAll = 0;
+  }
+
+  else if( p->iDoclistToken<0 ){
+    p->doclist.aAll = pList;
+    p->doclist.nAll = nList;
+  }
+
+  else if( p->doclist.aAll==0 ){
+    sqlite3_free(pList);
+  }
+
+  else {
+    char *pLeft;
+    char *pRight;
+    int nLeft;
+    int nRight;
+    int nDiff;
+
+    if( p->iDoclistToken<iToken ){
+      pLeft = p->doclist.aAll;
+      nLeft = p->doclist.nAll;
+      pRight = pList;
+      nRight = nList;
+      nDiff = iToken - p->iDoclistToken;
+    }else{
+      pRight = p->doclist.aAll;
+      nRight = p->doclist.nAll;
+      pLeft = pList;
+      nLeft = nList;
+      nDiff = p->iDoclistToken - iToken;
+    }
+
+    fts3DoclistPhraseMerge(pTab->bDescIdx, nDiff, pLeft, nLeft, pRight,&nRight);
+    sqlite3_free(pLeft);
+    p->doclist.aAll = pRight;
+    p->doclist.nAll = nRight;
+  }
+
+  if( iToken>p->iDoclistToken ) p->iDoclistToken = iToken;
+}
+
+/*
+** Load the doclist for phrase p into p->doclist.aAll/nAll. The loaded doclist
+** does not take deferred tokens into account.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalPhraseLoad(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p                   /* Phrase object */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int iToken;
+  int rc = SQLITE_OK;
+
+  for(iToken=0; rc==SQLITE_OK && iToken<p->nToken; iToken++){
+    Fts3PhraseToken *pToken = &p->aToken[iToken];
+    assert( pToken->pDeferred==0 || pToken->pSegcsr==0 );
+
+    if( pToken->pSegcsr ){
+      int nThis = 0;
+      char *pThis = 0;
+      rc = fts3TermSelect(pTab, pToken, p->iColumn, &nThis, &pThis);
+      if( rc==SQLITE_OK ){
+        fts3EvalPhraseMergeToken(pTab, p, iToken, pThis, nThis);
+      }
+    }
+    assert( pToken->pSegcsr==0 );
+  }
+
+  return rc;
+}
+
+/*
+** This function is called on each phrase after the position lists for
+** any deferred tokens have been loaded into memory. It updates the phrases
+** current position list to include only those positions that are really
+** instances of the phrase (after considering deferred tokens). If this
+** means that the phrase does not appear in the current row, doclist.pList
+** and doclist.nList are both zeroed.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
+  int iToken;                     /* Used to iterate through phrase tokens */
+  char *aPoslist = 0;             /* Position list for deferred tokens */
+  int nPoslist = 0;               /* Number of bytes in aPoslist */
+  int iPrev = -1;                 /* Token number of previous deferred token */
+
+  assert( pPhrase->doclist.bFreeList==0 );
+
+  for(iToken=0; iToken<pPhrase->nToken; iToken++){
+    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
+    Fts3DeferredToken *pDeferred = pToken->pDeferred;
+
+    if( pDeferred ){
+      char *pList;
+      int nList;
+      int rc = sqlite3Fts3DeferredTokenList(pDeferred, &pList, &nList);
+      if( rc!=SQLITE_OK ) return rc;
+
+      if( pList==0 ){
+        sqlite3_free(aPoslist);
+        pPhrase->doclist.pList = 0;
+        pPhrase->doclist.nList = 0;
+        return SQLITE_OK;
+
+      }else if( aPoslist==0 ){
+        aPoslist = pList;
+        nPoslist = nList;
+
+      }else{
+        char *aOut = pList;
+        char *p1 = aPoslist;
+        char *p2 = aOut;
+
+        assert( iPrev>=0 );
+        fts3PoslistPhraseMerge(&aOut, iToken-iPrev, 0, 1, &p1, &p2);
+        sqlite3_free(aPoslist);
+        aPoslist = pList;
+        nPoslist = (int)(aOut - aPoslist);
+        if( nPoslist==0 ){
+          sqlite3_free(aPoslist);
+          pPhrase->doclist.pList = 0;
+          pPhrase->doclist.nList = 0;
+          return SQLITE_OK;
+        }
+      }
+      iPrev = iToken;
+    }
+  }
+
+  if( iPrev>=0 ){
+    int nMaxUndeferred = pPhrase->iDoclistToken;
+    if( nMaxUndeferred<0 ){
+      pPhrase->doclist.pList = aPoslist;
+      pPhrase->doclist.nList = nPoslist;
+      pPhrase->doclist.iDocid = pCsr->iPrevId;
+      pPhrase->doclist.bFreeList = 1;
+    }else{
+      int nDistance;
+      char *p1;
+      char *p2;
+      char *aOut;
+
+      if( nMaxUndeferred>iPrev ){
+        p1 = aPoslist;
+        p2 = pPhrase->doclist.pList;
+        nDistance = nMaxUndeferred - iPrev;
+      }else{
+        p1 = pPhrase->doclist.pList;
+        p2 = aPoslist;
+        nDistance = iPrev - nMaxUndeferred;
+      }
+
+      aOut = (char *)sqlite3_malloc(nPoslist+8);
+      if( !aOut ){
+        sqlite3_free(aPoslist);
+        return SQLITE_NOMEM;
+      }
+      
+      pPhrase->doclist.pList = aOut;
+      if( fts3PoslistPhraseMerge(&aOut, nDistance, 0, 1, &p1, &p2) ){
+        pPhrase->doclist.bFreeList = 1;
+        pPhrase->doclist.nList = (int)(aOut - pPhrase->doclist.pList);
+      }else{
+        sqlite3_free(aOut);
+        pPhrase->doclist.pList = 0;
+        pPhrase->doclist.nList = 0;
+      }
+      sqlite3_free(aPoslist);
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** This function is called for each Fts3Phrase in a full-text query 
+** expression to initialize the mechanism for returning rows. Once this
+** function has been called successfully on an Fts3Phrase, it may be
+** used with fts3EvalPhraseNext() to iterate through the matching docids.
+**
+** If parameter bOptOk is true, then the phrase may (or may not) use the
+** incremental loading strategy. Otherwise, the entire doclist is loaded into
+** memory within this call.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalPhraseStart(Fts3Cursor *pCsr, int bOptOk, Fts3Phrase *p){
+  int rc;                         /* Error code */
+  Fts3PhraseToken *pFirst = &p->aToken[0];
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+
+  if( pCsr->bDesc==pTab->bDescIdx 
+   && bOptOk==1 
+   && p->nToken==1 
+   && pFirst->pSegcsr 
+   && pFirst->pSegcsr->bLookup 
+   && pFirst->bFirst==0
+  ){
+    /* Use the incremental approach. */
+    int iCol = (p->iColumn >= pTab->nColumn ? -1 : p->iColumn);
+    rc = sqlite3Fts3MsrIncrStart(
+        pTab, pFirst->pSegcsr, iCol, pFirst->z, pFirst->n);
+    p->bIncr = 1;
+
+  }else{
+    /* Load the full doclist for the phrase into memory. */
+    rc = fts3EvalPhraseLoad(pCsr, p);
+    p->bIncr = 0;
+  }
+
+  assert( rc!=SQLITE_OK || p->nToken<1 || p->aToken[0].pSegcsr==0 || p->bIncr );
+  return rc;
+}
+
+/*
+** This function is used to iterate backwards (from the end to start) 
+** through doclists. It is used by this module to iterate through phrase
+** doclists in reverse and by the fts3_write.c module to iterate through
+** pending-terms lists when writing to databases with "order=desc".
+**
+** The doclist may be sorted in ascending (parameter bDescIdx==0) or 
+** descending (parameter bDescIdx==1) order of docid. Regardless, this
+** function iterates from the end of the doclist to the beginning.
+*/
+SQLITE_PRIVATE void sqlite3Fts3DoclistPrev(
+  int bDescIdx,                   /* True if the doclist is desc */
+  char *aDoclist,                 /* Pointer to entire doclist */
+  int nDoclist,                   /* Length of aDoclist in bytes */
+  char **ppIter,                  /* IN/OUT: Iterator pointer */
+  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
+  int *pnList,                    /* OUT: List length pointer */
+  u8 *pbEof                       /* OUT: End-of-file flag */
+){
+  char *p = *ppIter;
+
+  assert( nDoclist>0 );
+  assert( *pbEof==0 );
+  assert( p || *piDocid==0 );
+  assert( !p || (p>aDoclist && p<&aDoclist[nDoclist]) );
+
+  if( p==0 ){
+    sqlite3_int64 iDocid = 0;
+    char *pNext = 0;
+    char *pDocid = aDoclist;
+    char *pEnd = &aDoclist[nDoclist];
+    int iMul = 1;
+
+    while( pDocid<pEnd ){
+      sqlite3_int64 iDelta;
+      pDocid += sqlite3Fts3GetVarint(pDocid, &iDelta);
+      iDocid += (iMul * iDelta);
+      pNext = pDocid;
+      fts3PoslistCopy(0, &pDocid);
+      while( pDocid<pEnd && *pDocid==0 ) pDocid++;
+      iMul = (bDescIdx ? -1 : 1);
+    }
+
+    *pnList = (int)(pEnd - pNext);
+    *ppIter = pNext;
+    *piDocid = iDocid;
+  }else{
+    int iMul = (bDescIdx ? -1 : 1);
+    sqlite3_int64 iDelta;
+    fts3GetReverseVarint(&p, aDoclist, &iDelta);
+    *piDocid -= (iMul * iDelta);
+
+    if( p==aDoclist ){
+      *pbEof = 1;
+    }else{
+      char *pSave = p;
+      fts3ReversePoslist(aDoclist, &p);
+      *pnList = (int)(pSave - p);
+    }
+    *ppIter = p;
+  }
+}
+
+/*
+** Iterate forwards through a doclist.
+*/
+SQLITE_PRIVATE void sqlite3Fts3DoclistNext(
+  int bDescIdx,                   /* True if the doclist is desc */
+  char *aDoclist,                 /* Pointer to entire doclist */
+  int nDoclist,                   /* Length of aDoclist in bytes */
+  char **ppIter,                  /* IN/OUT: Iterator pointer */
+  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
+  u8 *pbEof                       /* OUT: End-of-file flag */
+){
+  char *p = *ppIter;
+
+  assert( nDoclist>0 );
+  assert( *pbEof==0 );
+  assert( p || *piDocid==0 );
+  assert( !p || (p>=aDoclist && p<=&aDoclist[nDoclist]) );
+
+  if( p==0 ){
+    p = aDoclist;
+    p += sqlite3Fts3GetVarint(p, piDocid);
+  }else{
+    fts3PoslistCopy(0, &p);
+    if( p>=&aDoclist[nDoclist] ){
+      *pbEof = 1;
+    }else{
+      sqlite3_int64 iVar;
+      p += sqlite3Fts3GetVarint(p, &iVar);
+      *piDocid += ((bDescIdx ? -1 : 1) * iVar);
+    }
+  }
+
+  *ppIter = p;
+}
+
+/*
+** Attempt to move the phrase iterator to point to the next matching docid. 
+** If an error occurs, return an SQLite error code. Otherwise, return 
+** SQLITE_OK.
+**
+** If there is no "next" entry and no error occurs, then *pbEof is set to
+** 1 before returning. Otherwise, if no error occurs and the iterator is
+** successfully advanced, *pbEof is set to 0.
+*/
+static int fts3EvalPhraseNext(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p,                  /* Phrase object to advance to next docid */
+  u8 *pbEof                       /* OUT: Set to 1 if EOF */
+){
+  int rc = SQLITE_OK;
+  Fts3Doclist *pDL = &p->doclist;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+
+  if( p->bIncr ){
+    assert( p->nToken==1 );
+    assert( pDL->pNextDocid==0 );
+    rc = sqlite3Fts3MsrIncrNext(pTab, p->aToken[0].pSegcsr, 
+        &pDL->iDocid, &pDL->pList, &pDL->nList
+    );
+    if( rc==SQLITE_OK && !pDL->pList ){
+      *pbEof = 1;
+    }
+  }else if( pCsr->bDesc!=pTab->bDescIdx && pDL->nAll ){
+    sqlite3Fts3DoclistPrev(pTab->bDescIdx, pDL->aAll, pDL->nAll, 
+        &pDL->pNextDocid, &pDL->iDocid, &pDL->nList, pbEof
+    );
+    pDL->pList = pDL->pNextDocid;
+  }else{
+    char *pIter;                            /* Used to iterate through aAll */
+    char *pEnd = &pDL->aAll[pDL->nAll];     /* 1 byte past end of aAll */
+    if( pDL->pNextDocid ){
+      pIter = pDL->pNextDocid;
+    }else{
+      pIter = pDL->aAll;
+    }
+
+    if( pIter>=pEnd ){
+      /* We have already reached the end of this doclist. EOF. */
+      *pbEof = 1;
+    }else{
+      sqlite3_int64 iDelta;
+      pIter += sqlite3Fts3GetVarint(pIter, &iDelta);
+      if( pTab->bDescIdx==0 || pDL->pNextDocid==0 ){
+        pDL->iDocid += iDelta;
+      }else{
+        pDL->iDocid -= iDelta;
+      }
+      pDL->pList = pIter;
+      fts3PoslistCopy(0, &pIter);
+      pDL->nList = (int)(pIter - pDL->pList);
+
+      /* pIter now points just past the 0x00 that terminates the position-
+      ** list for document pDL->iDocid. However, if this position-list was
+      ** edited in place by fts3EvalNearTrim(), then pIter may not actually
+      ** point to the start of the next docid value. The following line deals
+      ** with this case by advancing pIter past the zero-padding added by
+      ** fts3EvalNearTrim().  */
+      while( pIter<pEnd && *pIter==0 ) pIter++;
+
+      pDL->pNextDocid = pIter;
+      assert( pIter>=&pDL->aAll[pDL->nAll] || *pIter );
+      *pbEof = 0;
+    }
+  }
+
+  return rc;
+}
+
+/*
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, fts3EvalPhraseStart() is called on all phrases within the
+** expression. Also the Fts3Expr.bDeferred variable is set to true for any
+** expressions for which all descendent tokens are deferred.
+**
+** If parameter bOptOk is zero, then it is guaranteed that the
+** Fts3Phrase.doclist.aAll/nAll variables contain the entire doclist for
+** each phrase in the expression (subject to deferred token processing).
+** Or, if bOptOk is non-zero, then one or more tokens within the expression
+** may be loaded incrementally, meaning doclist.aAll/nAll is not available.
+**
+** If an error occurs within this function, *pRc is set to an SQLite error
+** code before returning.
+*/
+static void fts3EvalStartReaders(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pExpr,                /* Expression to initialize phrases in */
+  int bOptOk,                     /* True to enable incremental loading */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( pExpr && SQLITE_OK==*pRc ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      int i;
+      int nToken = pExpr->pPhrase->nToken;
+      for(i=0; i<nToken; i++){
+        if( pExpr->pPhrase->aToken[i].pDeferred==0 ) break;
+      }
+      pExpr->bDeferred = (i==nToken);
+      *pRc = fts3EvalPhraseStart(pCsr, bOptOk, pExpr->pPhrase);
+    }else{
+      fts3EvalStartReaders(pCsr, pExpr->pLeft, bOptOk, pRc);
+      fts3EvalStartReaders(pCsr, pExpr->pRight, bOptOk, pRc);
+      pExpr->bDeferred = (pExpr->pLeft->bDeferred && pExpr->pRight->bDeferred);
+    }
+  }
+}
+
+/*
+** An array of the following structures is assembled as part of the process
+** of selecting tokens to defer before the query starts executing (as part
+** of the xFilter() method). There is one element in the array for each
+** token in the FTS expression.
+**
+** Tokens are divided into AND/NEAR clusters. All tokens in a cluster belong
+** to phrases that are connected only by AND and NEAR operators (not OR or
+** NOT). When determining tokens to defer, each AND/NEAR cluster is considered
+** separately. The root of a tokens AND/NEAR cluster is stored in 
+** Fts3TokenAndCost.pRoot.
+*/
+typedef struct Fts3TokenAndCost Fts3TokenAndCost;
+struct Fts3TokenAndCost {
+  Fts3Phrase *pPhrase;            /* The phrase the token belongs to */
+  int iToken;                     /* Position of token in phrase */
+  Fts3PhraseToken *pToken;        /* The token itself */
+  Fts3Expr *pRoot;                /* Root of NEAR/AND cluster */
+  int nOvfl;                      /* Number of overflow pages to load doclist */
+  int iCol;                       /* The column the token must match */
+};
+
+/*
+** This function is used to populate an allocated Fts3TokenAndCost array.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, if an error occurs during execution, *pRc is set to an
+** SQLite error code.
+*/
+static void fts3EvalTokenCosts(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pRoot,                /* Root of current AND/NEAR cluster */
+  Fts3Expr *pExpr,                /* Expression to consider */
+  Fts3TokenAndCost **ppTC,        /* Write new entries to *(*ppTC)++ */
+  Fts3Expr ***ppOr,               /* Write new OR root to *(*ppOr)++ */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      Fts3Phrase *pPhrase = pExpr->pPhrase;
+      int i;
+      for(i=0; *pRc==SQLITE_OK && i<pPhrase->nToken; i++){
+        Fts3TokenAndCost *pTC = (*ppTC)++;
+        pTC->pPhrase = pPhrase;
+        pTC->iToken = i;
+        pTC->pRoot = pRoot;
+        pTC->pToken = &pPhrase->aToken[i];
+        pTC->iCol = pPhrase->iColumn;
+        *pRc = sqlite3Fts3MsrOvfl(pCsr, pTC->pToken->pSegcsr, &pTC->nOvfl);
+      }
+    }else if( pExpr->eType!=FTSQUERY_NOT ){
+      assert( pExpr->eType==FTSQUERY_OR
+           || pExpr->eType==FTSQUERY_AND
+           || pExpr->eType==FTSQUERY_NEAR
+      );
+      assert( pExpr->pLeft && pExpr->pRight );
+      if( pExpr->eType==FTSQUERY_OR ){
+        pRoot = pExpr->pLeft;
+        **ppOr = pRoot;
+        (*ppOr)++;
+      }
+      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pLeft, ppTC, ppOr, pRc);
+      if( pExpr->eType==FTSQUERY_OR ){
+        pRoot = pExpr->pRight;
+        **ppOr = pRoot;
+        (*ppOr)++;
+      }
+      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pRight, ppTC, ppOr, pRc);
+    }
+  }
+}
+
+/*
+** Determine the average document (row) size in pages. If successful,
+** write this value to *pnPage and return SQLITE_OK. Otherwise, return
+** an SQLite error code.
+**
+** The average document size in pages is calculated by first calculating 
+** determining the average size in bytes, B. If B is less than the amount
+** of data that will fit on a single leaf page of an intkey table in
+** this database, then the average docsize is 1. Otherwise, it is 1 plus
+** the number of overflow pages consumed by a record B bytes in size.
+*/
+static int fts3EvalAverageDocsize(Fts3Cursor *pCsr, int *pnPage){
+  if( pCsr->nRowAvg==0 ){
+    /* The average document size, which is required to calculate the cost
+    ** of each doclist, has not yet been determined. Read the required 
+    ** data from the %_stat table to calculate it.
+    **
+    ** Entry 0 of the %_stat table is a blob containing (nCol+1) FTS3 
+    ** varints, where nCol is the number of columns in the FTS3 table.
+    ** The first varint is the number of documents currently stored in
+    ** the table. The following nCol varints contain the total amount of
+    ** data stored in all rows of each column of the table, from left
+    ** to right.
+    */
+    int rc;
+    Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
+    sqlite3_stmt *pStmt;
+    sqlite3_int64 nDoc = 0;
+    sqlite3_int64 nByte = 0;
+    const char *pEnd;
+    const char *a;
+
+    rc = sqlite3Fts3SelectDoctotal(p, &pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+    a = sqlite3_column_blob(pStmt, 0);
+    assert( a );
+
+    pEnd = &a[sqlite3_column_bytes(pStmt, 0)];
+    a += sqlite3Fts3GetVarint(a, &nDoc);
+    while( a<pEnd ){
+      a += sqlite3Fts3GetVarint(a, &nByte);
+    }
+    if( nDoc==0 || nByte==0 ){
+      sqlite3_reset(pStmt);
+      return FTS_CORRUPT_VTAB;
+    }
+
+    pCsr->nDoc = nDoc;
+    pCsr->nRowAvg = (int)(((nByte / nDoc) + p->nPgsz) / p->nPgsz);
+    assert( pCsr->nRowAvg>0 ); 
+    rc = sqlite3_reset(pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  *pnPage = pCsr->nRowAvg;
+  return SQLITE_OK;
+}
+
+/*
+** This function is called to select the tokens (if any) that will be 
+** deferred. The array aTC[] has already been populated when this is
+** called.
+**
+** This function is called once for each AND/NEAR cluster in the 
+** expression. Each invocation determines which tokens to defer within
+** the cluster with root node pRoot. See comments above the definition
+** of struct Fts3TokenAndCost for more details.
+**
+** If no error occurs, SQLITE_OK is returned and sqlite3Fts3DeferToken()
+** called on each token to defer. Otherwise, an SQLite error code is
+** returned.
+*/
+static int fts3EvalSelectDeferred(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pRoot,                /* Consider tokens with this root node */
+  Fts3TokenAndCost *aTC,          /* Array of expression tokens and costs */
+  int nTC                         /* Number of entries in aTC[] */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int nDocSize = 0;               /* Number of pages per doc loaded */
+  int rc = SQLITE_OK;             /* Return code */
+  int ii;                         /* Iterator variable for various purposes */
+  int nOvfl = 0;                  /* Total overflow pages used by doclists */
+  int nToken = 0;                 /* Total number of tokens in cluster */
+
+  int nMinEst = 0;                /* The minimum count for any phrase so far. */
+  int nLoad4 = 1;                 /* (Phrases that will be loaded)^4. */
+
+  /* Tokens are never deferred for FTS tables created using the content=xxx
+  ** option. The reason being that it is not guaranteed that the content
+  ** table actually contains the same data as the index. To prevent this from
+  ** causing any problems, the deferred token optimization is completely
+  ** disabled for content=xxx tables. */
+  if( pTab->zContentTbl ){
+    return SQLITE_OK;
+  }
+
+  /* Count the tokens in this AND/NEAR cluster. If none of the doclists
+  ** associated with the tokens spill onto overflow pages, or if there is
+  ** only 1 token, exit early. No tokens to defer in this case. */
+  for(ii=0; ii<nTC; ii++){
+    if( aTC[ii].pRoot==pRoot ){
+      nOvfl += aTC[ii].nOvfl;
+      nToken++;
+    }
+  }
+  if( nOvfl==0 || nToken<2 ) return SQLITE_OK;
+
+  /* Obtain the average docsize (in pages). */
+  rc = fts3EvalAverageDocsize(pCsr, &nDocSize);
+  assert( rc!=SQLITE_OK || nDocSize>0 );
+
+
+  /* Iterate through all tokens in this AND/NEAR cluster, in ascending order 
+  ** of the number of overflow pages that will be loaded by the pager layer 
+  ** to retrieve the entire doclist for the token from the full-text index.
+  ** Load the doclists for tokens that are either:
+  **
+  **   a. The cheapest token in the entire query (i.e. the one visited by the
+  **      first iteration of this loop), or
+  **
+  **   b. Part of a multi-token phrase.
+  **
+  ** After each token doclist is loaded, merge it with the others from the
+  ** same phrase and count the number of documents that the merged doclist
+  ** contains. Set variable "nMinEst" to the smallest number of documents in 
+  ** any phrase doclist for which 1 or more token doclists have been loaded.
+  ** Let nOther be the number of other phrases for which it is certain that
+  ** one or more tokens will not be deferred.
+  **
+  ** Then, for each token, defer it if loading the doclist would result in
+  ** loading N or more overflow pages into memory, where N is computed as:
+  **
+  **    (nMinEst + 4^nOther - 1) / (4^nOther)
+  */
+  for(ii=0; ii<nToken && rc==SQLITE_OK; ii++){
+    int iTC;                      /* Used to iterate through aTC[] array. */
+    Fts3TokenAndCost *pTC = 0;    /* Set to cheapest remaining token. */
+
+    /* Set pTC to point to the cheapest remaining token. */
+    for(iTC=0; iTC<nTC; iTC++){
+      if( aTC[iTC].pToken && aTC[iTC].pRoot==pRoot 
+       && (!pTC || aTC[iTC].nOvfl<pTC->nOvfl) 
+      ){
+        pTC = &aTC[iTC];
+      }
+    }
+    assert( pTC );
+
+    if( ii && pTC->nOvfl>=((nMinEst+(nLoad4/4)-1)/(nLoad4/4))*nDocSize ){
+      /* The number of overflow pages to load for this (and therefore all
+      ** subsequent) tokens is greater than the estimated number of pages 
+      ** that will be loaded if all subsequent tokens are deferred.
+      */
+      Fts3PhraseToken *pToken = pTC->pToken;
+      rc = sqlite3Fts3DeferToken(pCsr, pToken, pTC->iCol);
+      fts3SegReaderCursorFree(pToken->pSegcsr);
+      pToken->pSegcsr = 0;
+    }else{
+      /* Set nLoad4 to the value of (4^nOther) for the next iteration of the
+      ** for-loop. Except, limit the value to 2^24 to prevent it from 
+      ** overflowing the 32-bit integer it is stored in. */
+      if( ii<12 ) nLoad4 = nLoad4*4;
+
+      if( ii==0 || pTC->pPhrase->nToken>1 ){
+        /* Either this is the cheapest token in the entire query, or it is
+        ** part of a multi-token phrase. Either way, the entire doclist will
+        ** (eventually) be loaded into memory. It may as well be now. */
+        Fts3PhraseToken *pToken = pTC->pToken;
+        int nList = 0;
+        char *pList = 0;
+        rc = fts3TermSelect(pTab, pToken, pTC->iCol, &nList, &pList);
+        assert( rc==SQLITE_OK || pList==0 );
+        if( rc==SQLITE_OK ){
+          int nCount;
+          fts3EvalPhraseMergeToken(pTab, pTC->pPhrase, pTC->iToken,pList,nList);
+          nCount = fts3DoclistCountDocids(
+              pTC->pPhrase->doclist.aAll, pTC->pPhrase->doclist.nAll
+          );
+          if( ii==0 || nCount<nMinEst ) nMinEst = nCount;
+        }
+      }
+    }
+    pTC->pToken = 0;
+  }
+
+  return rc;
+}
+
+/*
+** This function is called from within the xFilter method. It initializes
+** the full-text query currently stored in pCsr->pExpr. To iterate through
+** the results of a query, the caller does:
+**
+**    fts3EvalStart(pCsr);
+**    while( 1 ){
+**      fts3EvalNext(pCsr);
+**      if( pCsr->bEof ) break;
+**      ... return row pCsr->iPrevId to the caller ...
+**    }
+*/
+static int fts3EvalStart(Fts3Cursor *pCsr){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int nToken = 0;
+  int nOr = 0;
+
+  /* Allocate a MultiSegReader for each token in the expression. */
+  fts3EvalAllocateReaders(pCsr, pCsr->pExpr, &nToken, &nOr, &rc);
+
+  /* Determine which, if any, tokens in the expression should be deferred. */
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+  if( rc==SQLITE_OK && nToken>1 && pTab->bFts4 ){
+    Fts3TokenAndCost *aTC;
+    Fts3Expr **apOr;
+    aTC = (Fts3TokenAndCost *)sqlite3_malloc(
+        sizeof(Fts3TokenAndCost) * nToken
+      + sizeof(Fts3Expr *) * nOr * 2
+    );
+    apOr = (Fts3Expr **)&aTC[nToken];
+
+    if( !aTC ){
+      rc = SQLITE_NOMEM;
+    }else{
+      int ii;
+      Fts3TokenAndCost *pTC = aTC;
+      Fts3Expr **ppOr = apOr;
+
+      fts3EvalTokenCosts(pCsr, 0, pCsr->pExpr, &pTC, &ppOr, &rc);
+      nToken = (int)(pTC-aTC);
+      nOr = (int)(ppOr-apOr);
+
+      if( rc==SQLITE_OK ){
+        rc = fts3EvalSelectDeferred(pCsr, 0, aTC, nToken);
+        for(ii=0; rc==SQLITE_OK && ii<nOr; ii++){
+          rc = fts3EvalSelectDeferred(pCsr, apOr[ii], aTC, nToken);
+        }
+      }
+
+      sqlite3_free(aTC);
+    }
+  }
+#endif
+
+  fts3EvalStartReaders(pCsr, pCsr->pExpr, 1, &rc);
+  return rc;
+}
+
+/*
+** Invalidate the current position list for phrase pPhrase.
+*/
+static void fts3EvalInvalidatePoslist(Fts3Phrase *pPhrase){
+  if( pPhrase->doclist.bFreeList ){
+    sqlite3_free(pPhrase->doclist.pList);
+  }
+  pPhrase->doclist.pList = 0;
+  pPhrase->doclist.nList = 0;
+  pPhrase->doclist.bFreeList = 0;
+}
+
+/*
+** This function is called to edit the position list associated with
+** the phrase object passed as the fifth argument according to a NEAR
+** condition. For example:
+**
+**     abc NEAR/5 "def ghi"
+**
+** Parameter nNear is passed the NEAR distance of the expression (5 in
+** the example above). When this function is called, *paPoslist points to
+** the position list, and *pnToken is the number of phrase tokens in, the
+** phrase on the other side of the NEAR operator to pPhrase. For example,
+** if pPhrase refers to the "def ghi" phrase, then *paPoslist points to
+** the position list associated with phrase "abc".
+**
+** All positions in the pPhrase position list that are not sufficiently
+** close to a position in the *paPoslist position list are removed. If this
+** leaves 0 positions, zero is returned. Otherwise, non-zero.
+**
+** Before returning, *paPoslist is set to point to the position lsit 
+** associated with pPhrase. And *pnToken is set to the number of tokens in
+** pPhrase.
+*/
+static int fts3EvalNearTrim(
+  int nNear,                      /* NEAR distance. As in "NEAR/nNear". */
+  char *aTmp,                     /* Temporary space to use */
+  char **paPoslist,               /* IN/OUT: Position list */
+  int *pnToken,                   /* IN/OUT: Tokens in phrase of *paPoslist */
+  Fts3Phrase *pPhrase             /* The phrase object to trim the doclist of */
+){
+  int nParam1 = nNear + pPhrase->nToken;
+  int nParam2 = nNear + *pnToken;
+  int nNew;
+  char *p2; 
+  char *pOut; 
+  int res;
+
+  assert( pPhrase->doclist.pList );
+
+  p2 = pOut = pPhrase->doclist.pList;
+  res = fts3PoslistNearMerge(
+    &pOut, aTmp, nParam1, nParam2, paPoslist, &p2
+  );
+  if( res ){
+    nNew = (int)(pOut - pPhrase->doclist.pList) - 1;
+    assert( pPhrase->doclist.pList[nNew]=='\0' );
+    assert( nNew<=pPhrase->doclist.nList && nNew>0 );
+    memset(&pPhrase->doclist.pList[nNew], 0, pPhrase->doclist.nList - nNew);
+    pPhrase->doclist.nList = nNew;
+    *paPoslist = pPhrase->doclist.pList;
+    *pnToken = pPhrase->nToken;
+  }
+
+  return res;
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is called.
+** Otherwise, it advances the expression passed as the second argument to
+** point to the next matching row in the database. Expressions iterate through
+** matching rows in docid order. Ascending order if Fts3Cursor.bDesc is zero,
+** or descending if it is non-zero.
+**
+** If an error occurs, *pRc is set to an SQLite error code. Otherwise, if
+** successful, the following variables in pExpr are set:
+**
+**   Fts3Expr.bEof                (non-zero if EOF - there is no next row)
+**   Fts3Expr.iDocid              (valid if bEof==0. The docid of the next row)
+**
+** If the expression is of type FTSQUERY_PHRASE, and the expression is not
+** at EOF, then the following variables are populated with the position list
+** for the phrase for the visited row:
+**
+**   FTs3Expr.pPhrase->doclist.nList        (length of pList in bytes)
+**   FTs3Expr.pPhrase->doclist.pList        (pointer to position list)
+**
+** It says above that this function advances the expression to the next
+** matching row. This is usually true, but there are the following exceptions:
+**
+**   1. Deferred tokens are not taken into account. If a phrase consists
+**      entirely of deferred tokens, it is assumed to match every row in
+**      the db. In this case the position-list is not populated at all. 
+**
+**      Or, if a phrase contains one or more deferred tokens and one or
+**      more non-deferred tokens, then the expression is advanced to the 
+**      next possible match, considering only non-deferred tokens. In other
+**      words, if the phrase is "A B C", and "B" is deferred, the expression
+**      is advanced to the next row that contains an instance of "A * C", 
+**      where "*" may match any single token. The position list in this case
+**      is populated as for "A * C" before returning.
+**
+**   2. NEAR is treated as AND. If the expression is "x NEAR y", it is 
+**      advanced to point to the next row that matches "x AND y".
+** 
+** See fts3EvalTestDeferredAndNear() for details on testing if a row is
+** really a match, taking into account deferred tokens and NEAR operators.
+*/
+static void fts3EvalNextRow(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pExpr,                /* Expr. to advance to next matching row */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK ){
+    int bDescDoclist = pCsr->bDesc;         /* Used by DOCID_CMP() macro */
+    assert( pExpr->bEof==0 );
+    pExpr->bStart = 1;
+
+    switch( pExpr->eType ){
+      case FTSQUERY_NEAR:
+      case FTSQUERY_AND: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+        assert( !pLeft->bDeferred || !pRight->bDeferred );
+
+        if( pLeft->bDeferred ){
+          /* LHS is entirely deferred. So we assume it matches every row.
+          ** Advance the RHS iterator to find the next row visited. */
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          pExpr->iDocid = pRight->iDocid;
+          pExpr->bEof = pRight->bEof;
+        }else if( pRight->bDeferred ){
+          /* RHS is entirely deferred. So we assume it matches every row.
+          ** Advance the LHS iterator to find the next row visited. */
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          pExpr->iDocid = pLeft->iDocid;
+          pExpr->bEof = pLeft->bEof;
+        }else{
+          /* Neither the RHS or LHS are deferred. */
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          while( !pLeft->bEof && !pRight->bEof && *pRc==SQLITE_OK ){
+            sqlite3_int64 iDiff = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+            if( iDiff==0 ) break;
+            if( iDiff<0 ){
+              fts3EvalNextRow(pCsr, pLeft, pRc);
+            }else{
+              fts3EvalNextRow(pCsr, pRight, pRc);
+            }
+          }
+          pExpr->iDocid = pLeft->iDocid;
+          pExpr->bEof = (pLeft->bEof || pRight->bEof);
+        }
+        break;
+      }
+  
+      case FTSQUERY_OR: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+        sqlite3_int64 iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+
+        assert( pLeft->bStart || pLeft->iDocid==pRight->iDocid );
+        assert( pRight->bStart || pLeft->iDocid==pRight->iDocid );
+
+        if( pRight->bEof || (pLeft->bEof==0 && iCmp<0) ){
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+        }else if( pLeft->bEof || (pRight->bEof==0 && iCmp>0) ){
+          fts3EvalNextRow(pCsr, pRight, pRc);
+        }else{
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          fts3EvalNextRow(pCsr, pRight, pRc);
+        }
+
+        pExpr->bEof = (pLeft->bEof && pRight->bEof);
+        iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+        if( pRight->bEof || (pLeft->bEof==0 &&  iCmp<0) ){
+          pExpr->iDocid = pLeft->iDocid;
+        }else{
+          pExpr->iDocid = pRight->iDocid;
+        }
+
+        break;
+      }
+
+      case FTSQUERY_NOT: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+
+        if( pRight->bStart==0 ){
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          assert( *pRc!=SQLITE_OK || pRight->bStart );
+        }
+
+        fts3EvalNextRow(pCsr, pLeft, pRc);
+        if( pLeft->bEof==0 ){
+          while( !*pRc 
+              && !pRight->bEof 
+              && DOCID_CMP(pLeft->iDocid, pRight->iDocid)>0 
+          ){
+            fts3EvalNextRow(pCsr, pRight, pRc);
+          }
+        }
+        pExpr->iDocid = pLeft->iDocid;
+        pExpr->bEof = pLeft->bEof;
+        break;
+      }
+
+      default: {
+        Fts3Phrase *pPhrase = pExpr->pPhrase;
+        fts3EvalInvalidatePoslist(pPhrase);
+        *pRc = fts3EvalPhraseNext(pCsr, pPhrase, &pExpr->bEof);
+        pExpr->iDocid = pPhrase->doclist.iDocid;
+        break;
+      }
+    }
+  }
+}
+
+/*
+** If *pRc is not SQLITE_OK, or if pExpr is not the root node of a NEAR
+** cluster, then this function returns 1 immediately.
+**
+** Otherwise, it checks if the current row really does match the NEAR 
+** expression, using the data currently stored in the position lists 
+** (Fts3Expr->pPhrase.doclist.pList/nList) for each phrase in the expression. 
+**
+** If the current row is a match, the position list associated with each
+** phrase in the NEAR expression is edited in place to contain only those
+** phrase instances sufficiently close to their peers to satisfy all NEAR
+** constraints. In this case it returns 1. If the NEAR expression does not 
+** match the current row, 0 is returned. The position lists may or may not
+** be edited if 0 is returned.
+*/
+static int fts3EvalNearTest(Fts3Expr *pExpr, int *pRc){
+  int res = 1;
+
+  /* The following block runs if pExpr is the root of a NEAR query.
+  ** For example, the query:
+  **
+  **         "w" NEAR "x" NEAR "y" NEAR "z"
+  **
+  ** which is represented in tree form as:
+  **
+  **                               |
+  **                          +--NEAR--+      <-- root of NEAR query
+  **                          |        |
+  **                     +--NEAR--+   "z"
+  **                     |        |
+  **                +--NEAR--+   "y"
+  **                |        |
+  **               "w"      "x"
+  **
+  ** The right-hand child of a NEAR node is always a phrase. The 
+  ** left-hand child may be either a phrase or a NEAR node. There are
+  ** no exceptions to this - it's the way the parser in fts3_expr.c works.
+  */
+  if( *pRc==SQLITE_OK 
+   && pExpr->eType==FTSQUERY_NEAR 
+   && pExpr->bEof==0
+   && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
+  ){
+    Fts3Expr *p; 
+    int nTmp = 0;                 /* Bytes of temp space */
+    char *aTmp;                   /* Temp space for PoslistNearMerge() */
+
+    /* Allocate temporary working space. */
+    for(p=pExpr; p->pLeft; p=p->pLeft){
+      nTmp += p->pRight->pPhrase->doclist.nList;
+    }
+    nTmp += p->pPhrase->doclist.nList;
+    aTmp = sqlite3_malloc(nTmp*2);
+    if( !aTmp ){
+      *pRc = SQLITE_NOMEM;
+      res = 0;
+    }else{
+      char *aPoslist = p->pPhrase->doclist.pList;
+      int nToken = p->pPhrase->nToken;
+
+      for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){
+        Fts3Phrase *pPhrase = p->pRight->pPhrase;
+        int nNear = p->nNear;
+        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
+      }
+  
+      aPoslist = pExpr->pRight->pPhrase->doclist.pList;
+      nToken = pExpr->pRight->pPhrase->nToken;
+      for(p=pExpr->pLeft; p && res; p=p->pLeft){
+        int nNear;
+        Fts3Phrase *pPhrase;
+        assert( p->pParent && p->pParent->pLeft==p );
+        nNear = p->pParent->nNear;
+        pPhrase = (
+            p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase
+        );
+        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
+      }
+    }
+
+    sqlite3_free(aTmp);
+  }
+
+  return res;
+}
+
+/*
+** This function is a helper function for fts3EvalTestDeferredAndNear().
+** Assuming no error occurs or has occurred, It returns non-zero if the
+** expression passed as the second argument matches the row that pCsr 
+** currently points to, or zero if it does not.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** If an error occurs during execution of this function, *pRc is set to 
+** the appropriate SQLite error code. In this case the returned value is 
+** undefined.
+*/
+static int fts3EvalTestExpr(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Expr to test. May or may not be root. */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int bHit = 1;                   /* Return value */
+  if( *pRc==SQLITE_OK ){
+    switch( pExpr->eType ){
+      case FTSQUERY_NEAR:
+      case FTSQUERY_AND:
+        bHit = (
+            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
+         && fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
+         && fts3EvalNearTest(pExpr, pRc)
+        );
+
+        /* If the NEAR expression does not match any rows, zero the doclist for 
+        ** all phrases involved in the NEAR. This is because the snippet(),
+        ** offsets() and matchinfo() functions are not supposed to recognize 
+        ** any instances of phrases that are part of unmatched NEAR queries. 
+        ** For example if this expression:
+        **
+        **    ... MATCH 'a OR (b NEAR c)'
+        **
+        ** is matched against a row containing:
+        **
+        **        'a b d e'
+        **
+        ** then any snippet() should ony highlight the "a" term, not the "b"
+        ** (as "b" is part of a non-matching NEAR clause).
+        */
+        if( bHit==0 
+         && pExpr->eType==FTSQUERY_NEAR 
+         && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
+        ){
+          Fts3Expr *p;
+          for(p=pExpr; p->pPhrase==0; p=p->pLeft){
+            if( p->pRight->iDocid==pCsr->iPrevId ){
+              fts3EvalInvalidatePoslist(p->pRight->pPhrase);
+            }
+          }
+          if( p->iDocid==pCsr->iPrevId ){
+            fts3EvalInvalidatePoslist(p->pPhrase);
+          }
+        }
+
+        break;
+
+      case FTSQUERY_OR: {
+        int bHit1 = fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc);
+        int bHit2 = fts3EvalTestExpr(pCsr, pExpr->pRight, pRc);
+        bHit = bHit1 || bHit2;
+        break;
+      }
+
+      case FTSQUERY_NOT:
+        bHit = (
+            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
+         && !fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
+        );
+        break;
+
+      default: {
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+        if( pCsr->pDeferred 
+         && (pExpr->iDocid==pCsr->iPrevId || pExpr->bDeferred)
+        ){
+          Fts3Phrase *pPhrase = pExpr->pPhrase;
+          assert( pExpr->bDeferred || pPhrase->doclist.bFreeList==0 );
+          if( pExpr->bDeferred ){
+            fts3EvalInvalidatePoslist(pPhrase);
+          }
+          *pRc = fts3EvalDeferredPhrase(pCsr, pPhrase);
+          bHit = (pPhrase->doclist.pList!=0);
+          pExpr->iDocid = pCsr->iPrevId;
+        }else
+#endif
+        {
+          bHit = (pExpr->bEof==0 && pExpr->iDocid==pCsr->iPrevId);
+        }
+        break;
+      }
+    }
+  }
+  return bHit;
+}
+
+/*
+** This function is called as the second part of each xNext operation when
+** iterating through the results of a full-text query. At this point the
+** cursor points to a row that matches the query expression, with the
+** following caveats:
+**
+**   * Up until this point, "NEAR" operators in the expression have been
+**     treated as "AND".
+**
+**   * Deferred tokens have not yet been considered.
+**
+** If *pRc is not SQLITE_OK when this function is called, it immediately
+** returns 0. Otherwise, it tests whether or not after considering NEAR
+** operators and deferred tokens the current row is still a match for the
+** expression. It returns 1 if both of the following are true:
+**
+**   1. *pRc is SQLITE_OK when this function returns, and
+**
+**   2. After scanning the current FTS table row for the deferred tokens,
+**      it is determined that the row does *not* match the query.
+**
+** Or, if no error occurs and it seems the current row does match the FTS
+** query, return 0.
+*/
+static int fts3EvalTestDeferredAndNear(Fts3Cursor *pCsr, int *pRc){
+  int rc = *pRc;
+  int bMiss = 0;
+  if( rc==SQLITE_OK ){
+
+    /* If there are one or more deferred tokens, load the current row into
+    ** memory and scan it to determine the position list for each deferred
+    ** token. Then, see if this row is really a match, considering deferred
+    ** tokens and NEAR operators (neither of which were taken into account
+    ** earlier, by fts3EvalNextRow()). 
+    */
+    if( pCsr->pDeferred ){
+      rc = fts3CursorSeek(0, pCsr);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3Fts3CacheDeferredDoclists(pCsr);
+      }
+    }
+    bMiss = (0==fts3EvalTestExpr(pCsr, pCsr->pExpr, &rc));
+
+    /* Free the position-lists accumulated for each deferred token above. */
+    sqlite3Fts3FreeDeferredDoclists(pCsr);
+    *pRc = rc;
+  }
+  return (rc==SQLITE_OK && bMiss);
+}
+
+/*
+** Advance to the next document that matches the FTS expression in
+** Fts3Cursor.pExpr.
+*/
+static int fts3EvalNext(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Expr *pExpr = pCsr->pExpr;
+  assert( pCsr->isEof==0 );
+  if( pExpr==0 ){
+    pCsr->isEof = 1;
+  }else{
+    do {
+      if( pCsr->isRequireSeek==0 ){
+        sqlite3_reset(pCsr->pStmt);
+      }
+      assert( sqlite3_data_count(pCsr->pStmt)==0 );
+      fts3EvalNextRow(pCsr, pExpr, &rc);
+      pCsr->isEof = pExpr->bEof;
+      pCsr->isRequireSeek = 1;
+      pCsr->isMatchinfoNeeded = 1;
+      pCsr->iPrevId = pExpr->iDocid;
+    }while( pCsr->isEof==0 && fts3EvalTestDeferredAndNear(pCsr, &rc) );
+  }
+  return rc;
+}
+
+/*
+** Restart interation for expression pExpr so that the next call to
+** fts3EvalNext() visits the first row. Do not allow incremental 
+** loading or merging of phrase doclists for this iteration.
+**
+** If *pRc is other than SQLITE_OK when this function is called, it is
+** a no-op. If an error occurs within this function, *pRc is set to an
+** SQLite error code before returning.
+*/
+static void fts3EvalRestart(
+  Fts3Cursor *pCsr,
+  Fts3Expr *pExpr,
+  int *pRc
+){
+  if( pExpr && *pRc==SQLITE_OK ){
+    Fts3Phrase *pPhrase = pExpr->pPhrase;
+
+    if( pPhrase ){
+      fts3EvalInvalidatePoslist(pPhrase);
+      if( pPhrase->bIncr ){
+        assert( pPhrase->nToken==1 );
+        assert( pPhrase->aToken[0].pSegcsr );
+        sqlite3Fts3MsrIncrRestart(pPhrase->aToken[0].pSegcsr);
+        *pRc = fts3EvalPhraseStart(pCsr, 0, pPhrase);
+      }
+
+      pPhrase->doclist.pNextDocid = 0;
+      pPhrase->doclist.iDocid = 0;
+    }
+
+    pExpr->iDocid = 0;
+    pExpr->bEof = 0;
+    pExpr->bStart = 0;
+
+    fts3EvalRestart(pCsr, pExpr->pLeft, pRc);
+    fts3EvalRestart(pCsr, pExpr->pRight, pRc);
+  }
+}
+
+/*
+** After allocating the Fts3Expr.aMI[] array for each phrase in the 
+** expression rooted at pExpr, the cursor iterates through all rows matched
+** by pExpr, calling this function for each row. This function increments
+** the values in Fts3Expr.aMI[] according to the position-list currently
+** found in Fts3Expr.pPhrase->doclist.pList for each of the phrase 
+** expression nodes.
+*/
+static void fts3EvalUpdateCounts(Fts3Expr *pExpr){
+  if( pExpr ){
+    Fts3Phrase *pPhrase = pExpr->pPhrase;
+    if( pPhrase && pPhrase->doclist.pList ){
+      int iCol = 0;
+      char *p = pPhrase->doclist.pList;
+
+      assert( *p );
+      while( 1 ){
+        u8 c = 0;
+        int iCnt = 0;
+        while( 0xFE & (*p | c) ){
+          if( (c&0x80)==0 ) iCnt++;
+          c = *p++ & 0x80;
+        }
+
+        /* aMI[iCol*3 + 1] = Number of occurrences
+        ** aMI[iCol*3 + 2] = Number of rows containing at least one instance
+        */
+        pExpr->aMI[iCol*3 + 1] += iCnt;
+        pExpr->aMI[iCol*3 + 2] += (iCnt>0);
+        if( *p==0x00 ) break;
+        p++;
+        p += sqlite3Fts3GetVarint32(p, &iCol);
+      }
+    }
+
+    fts3EvalUpdateCounts(pExpr->pLeft);
+    fts3EvalUpdateCounts(pExpr->pRight);
+  }
+}
+
+/*
+** Expression pExpr must be of type FTSQUERY_PHRASE.
+**
+** If it is not already allocated and populated, this function allocates and
+** populates the Fts3Expr.aMI[] array for expression pExpr. If pExpr is part
+** of a NEAR expression, then it also allocates and populates the same array
+** for all other phrases that are part of the NEAR expression.
+**
+** SQLITE_OK is returned if the aMI[] array is successfully allocated and
+** populated. Otherwise, if an error occurs, an SQLite error code is returned.
+*/
+static int fts3EvalGatherStats(
+  Fts3Cursor *pCsr,               /* Cursor object */
+  Fts3Expr *pExpr                 /* FTSQUERY_PHRASE expression */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( pExpr->eType==FTSQUERY_PHRASE );
+  if( pExpr->aMI==0 ){
+    Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+    Fts3Expr *pRoot;                /* Root of NEAR expression */
+    Fts3Expr *p;                    /* Iterator used for several purposes */
+
+    sqlite3_int64 iPrevId = pCsr->iPrevId;
+    sqlite3_int64 iDocid;
+    u8 bEof;
+
+    /* Find the root of the NEAR expression */
+    pRoot = pExpr;
+    while( pRoot->pParent && pRoot->pParent->eType==FTSQUERY_NEAR ){
+      pRoot = pRoot->pParent;
+    }
+    iDocid = pRoot->iDocid;
+    bEof = pRoot->bEof;
+    assert( pRoot->bStart );
+
+    /* Allocate space for the aMSI[] array of each FTSQUERY_PHRASE node */
+    for(p=pRoot; p; p=p->pLeft){
+      Fts3Expr *pE = (p->eType==FTSQUERY_PHRASE?p:p->pRight);
+      assert( pE->aMI==0 );
+      pE->aMI = (u32 *)sqlite3_malloc(pTab->nColumn * 3 * sizeof(u32));
+      if( !pE->aMI ) return SQLITE_NOMEM;
+      memset(pE->aMI, 0, pTab->nColumn * 3 * sizeof(u32));
+    }
+
+    fts3EvalRestart(pCsr, pRoot, &rc);
+
+    while( pCsr->isEof==0 && rc==SQLITE_OK ){
+
+      do {
+        /* Ensure the %_content statement is reset. */
+        if( pCsr->isRequireSeek==0 ) sqlite3_reset(pCsr->pStmt);
+        assert( sqlite3_data_count(pCsr->pStmt)==0 );
+
+        /* Advance to the next document */
+        fts3EvalNextRow(pCsr, pRoot, &rc);
+        pCsr->isEof = pRoot->bEof;
+        pCsr->isRequireSeek = 1;
+        pCsr->isMatchinfoNeeded = 1;
+        pCsr->iPrevId = pRoot->iDocid;
+      }while( pCsr->isEof==0 
+           && pRoot->eType==FTSQUERY_NEAR 
+           && fts3EvalTestDeferredAndNear(pCsr, &rc) 
+      );
+
+      if( rc==SQLITE_OK && pCsr->isEof==0 ){
+        fts3EvalUpdateCounts(pRoot);
+      }
+    }
+
+    pCsr->isEof = 0;
+    pCsr->iPrevId = iPrevId;
+
+    if( bEof ){
+      pRoot->bEof = bEof;
+    }else{
+      /* Caution: pRoot may iterate through docids in ascending or descending
+      ** order. For this reason, even though it seems more defensive, the 
+      ** do loop can not be written:
+      **
+      **   do {...} while( pRoot->iDocid<iDocid && rc==SQLITE_OK );
+      */
+      fts3EvalRestart(pCsr, pRoot, &rc);
+      do {
+        fts3EvalNextRow(pCsr, pRoot, &rc);
+        assert( pRoot->bEof==0 );
+      }while( pRoot->iDocid!=iDocid && rc==SQLITE_OK );
+      fts3EvalTestDeferredAndNear(pCsr, &rc);
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is used by the matchinfo() module to query a phrase 
+** expression node for the following information:
+**
+**   1. The total number of occurrences of the phrase in each column of 
+**      the FTS table (considering all rows), and
+**
+**   2. For each column, the number of rows in the table for which the
+**      column contains at least one instance of the phrase.
+**
+** If no error occurs, SQLITE_OK is returned and the values for each column
+** written into the array aiOut as follows:
+**
+**   aiOut[iCol*3 + 1] = Number of occurrences
+**   aiOut[iCol*3 + 2] = Number of rows containing at least one instance
+**
+** Caveats:
+**
+**   * If a phrase consists entirely of deferred tokens, then all output 
+**     values are set to the number of documents in the table. In other
+**     words we assume that very common tokens occur exactly once in each 
+**     column of each row of the table.
+**
+**   * If a phrase contains some deferred tokens (and some non-deferred 
+**     tokens), count the potential occurrence identified by considering
+**     the non-deferred tokens instead of actual phrase occurrences.
+**
+**   * If the phrase is part of a NEAR expression, then only phrase instances
+**     that meet the NEAR constraint are included in the counts.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Phrase expression */
+  u32 *aiOut                      /* Array to write results into (see above) */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int iCol;
+
+  if( pExpr->bDeferred && pExpr->pParent->eType!=FTSQUERY_NEAR ){
+    assert( pCsr->nDoc>0 );
+    for(iCol=0; iCol<pTab->nColumn; iCol++){
+      aiOut[iCol*3 + 1] = (u32)pCsr->nDoc;
+      aiOut[iCol*3 + 2] = (u32)pCsr->nDoc;
+    }
+  }else{
+    rc = fts3EvalGatherStats(pCsr, pExpr);
+    if( rc==SQLITE_OK ){
+      assert( pExpr->aMI );
+      for(iCol=0; iCol<pTab->nColumn; iCol++){
+        aiOut[iCol*3 + 1] = pExpr->aMI[iCol*3 + 1];
+        aiOut[iCol*3 + 2] = pExpr->aMI[iCol*3 + 2];
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The expression pExpr passed as the second argument to this function
+** must be of type FTSQUERY_PHRASE. 
+**
+** The returned value is either NULL or a pointer to a buffer containing
+** a position-list indicating the occurrences of the phrase in column iCol
+** of the current row. 
+**
+** More specifically, the returned buffer contains 1 varint for each 
+** occurence of the phrase in the column, stored using the normal (delta+2) 
+** compression and is terminated by either an 0x01 or 0x00 byte. For example,
+** if the requested column contains "a b X c d X X" and the position-list
+** for 'X' is requested, the buffer returned may contain:
+**
+**     0x04 0x05 0x03 0x01   or   0x04 0x05 0x03 0x00
+**
+** This function works regardless of whether or not the phrase is deferred,
+** incremental, or neither.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(
+  Fts3Cursor *pCsr,               /* FTS3 cursor object */
+  Fts3Expr *pExpr,                /* Phrase to return doclist for */
+  int iCol,                       /* Column to return position list for */
+  char **ppOut                    /* OUT: Pointer to position list */
+){
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  char *pIter;
+  int iThis;
+  sqlite3_int64 iDocid;
+
+  /* If this phrase is applies specifically to some column other than 
+  ** column iCol, return a NULL pointer.  */
+  *ppOut = 0;
+  assert( iCol>=0 && iCol<pTab->nColumn );
+  if( (pPhrase->iColumn<pTab->nColumn && pPhrase->iColumn!=iCol) ){
+    return SQLITE_OK;
+  }
+
+  iDocid = pExpr->iDocid;
+  pIter = pPhrase->doclist.pList;
+  if( iDocid!=pCsr->iPrevId || pExpr->bEof ){
+    int bDescDoclist = pTab->bDescIdx;      /* For DOCID_CMP macro */
+    int bOr = 0;
+    u8 bEof = 0;
+    Fts3Expr *p;
+
+    /* Check if this phrase descends from an OR expression node. If not, 
+    ** return NULL. Otherwise, the entry that corresponds to docid 
+    ** pCsr->iPrevId may lie earlier in the doclist buffer. */
+    for(p=pExpr->pParent; p; p=p->pParent){
+      if( p->eType==FTSQUERY_OR ) bOr = 1;
+    }
+    if( bOr==0 ) return SQLITE_OK;
+
+    /* This is the descendent of an OR node. In this case we cannot use
+    ** an incremental phrase. Load the entire doclist for the phrase
+    ** into memory in this case.  */
+    if( pPhrase->bIncr ){
+      int rc = SQLITE_OK;
+      int bEofSave = pExpr->bEof;
+      fts3EvalRestart(pCsr, pExpr, &rc);
+      while( rc==SQLITE_OK && !pExpr->bEof ){
+        fts3EvalNextRow(pCsr, pExpr, &rc);
+        if( bEofSave==0 && pExpr->iDocid==iDocid ) break;
+      }
+      pIter = pPhrase->doclist.pList;
+      assert( rc!=SQLITE_OK || pPhrase->bIncr==0 );
+      if( rc!=SQLITE_OK ) return rc;
+    }
+
+    if( pExpr->bEof ){
+      pIter = 0;
+      iDocid = 0;
+    }
+    bEof = (pPhrase->doclist.nAll==0);
+    assert( bDescDoclist==0 || bDescDoclist==1 );
+    assert( pCsr->bDesc==0 || pCsr->bDesc==1 );
+
+    if( pCsr->bDesc==bDescDoclist ){
+      int dummy;
+      while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)>0 ) && bEof==0 ){
+        sqlite3Fts3DoclistPrev(
+            bDescDoclist, pPhrase->doclist.aAll, pPhrase->doclist.nAll, 
+            &pIter, &iDocid, &dummy, &bEof
+        );
+      }
+    }else{
+      while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)<0 ) && bEof==0 ){
+        sqlite3Fts3DoclistNext(
+            bDescDoclist, pPhrase->doclist.aAll, pPhrase->doclist.nAll, 
+            &pIter, &iDocid, &bEof
+        );
+      }
+    }
+
+    if( bEof || iDocid!=pCsr->iPrevId ) pIter = 0;
+  }
+  if( pIter==0 ) return SQLITE_OK;
+
+  if( *pIter==0x01 ){
+    pIter++;
+    pIter += sqlite3Fts3GetVarint32(pIter, &iThis);
+  }else{
+    iThis = 0;
+  }
+  while( iThis<iCol ){
+    fts3ColumnlistCopy(0, &pIter);
+    if( *pIter==0x00 ) return 0;
+    pIter++;
+    pIter += sqlite3Fts3GetVarint32(pIter, &iThis);
+  }
+
+  *ppOut = ((iCol==iThis)?pIter:0);
+  return SQLITE_OK;
+}
+
+/*
+** Free all components of the Fts3Phrase structure that were allocated by
+** the eval module. Specifically, this means to free:
+**
+**   * the contents of pPhrase->doclist, and
+**   * any Fts3MultiSegReader objects held by phrase tokens.
+*/
+SQLITE_PRIVATE void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *pPhrase){
+  if( pPhrase ){
+    int i;
+    sqlite3_free(pPhrase->doclist.aAll);
+    fts3EvalInvalidatePoslist(pPhrase);
+    memset(&pPhrase->doclist, 0, sizeof(Fts3Doclist));
+    for(i=0; i<pPhrase->nToken; i++){
+      fts3SegReaderCursorFree(pPhrase->aToken[i].pSegcsr);
+      pPhrase->aToken[i].pSegcsr = 0;
+    }
+  }
+}
+
+
+/*
+** Return SQLITE_CORRUPT_VTAB.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3Fts3Corrupt(){
+  return SQLITE_CORRUPT_VTAB;
+}
+#endif
+
 #if !SQLITE_CORE
+/*
+** Initialize API pointer table, if required.
+*/
 SQLITE_API int sqlite3_extension_init(
   sqlite3 *db, 
   char **pzErrMsg,
@@ -96778,9 +121287,485 @@ SQLITE_API int sqlite3_extension_init(
 }
 #endif
 
-#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+#endif
 
 /************** End of fts3.c ************************************************/
+/************** Begin file fts3_aux.c ****************************************/
+/*
+** 2011 Jan 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+typedef struct Fts3auxTable Fts3auxTable;
+typedef struct Fts3auxCursor Fts3auxCursor;
+
+struct Fts3auxTable {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  Fts3Table *pFts3Tab;
+};
+
+struct Fts3auxCursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  Fts3MultiSegReader csr;        /* Must be right after "base" */
+  Fts3SegFilter filter;
+  char *zStop;
+  int nStop;                      /* Byte-length of string zStop */
+  int isEof;                      /* True if cursor is at EOF */
+  sqlite3_int64 iRowid;           /* Current rowid */
+
+  int iCol;                       /* Current value of 'col' column */
+  int nStat;                      /* Size of aStat[] array */
+  struct Fts3auxColstats {
+    sqlite3_int64 nDoc;           /* 'documents' values for current csr row */
+    sqlite3_int64 nOcc;           /* 'occurrences' values for current csr row */
+  } *aStat;
+};
+
+/*
+** Schema of the terms table.
+*/
+#define FTS3_TERMS_SCHEMA "CREATE TABLE x(term, col, documents, occurrences)"
+
+/*
+** This function does all the work for both the xConnect and xCreate methods.
+** These tables have no persistent representation of their own, so xConnect
+** and xCreate are identical operations.
+*/
+static int fts3auxConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pUnused,                  /* Unused */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  char const *zDb;                /* Name of database (e.g. "main") */
+  char const *zFts3;              /* Name of fts3 table */
+  int nDb;                        /* Result of strlen(zDb) */
+  int nFts3;                      /* Result of strlen(zFts3) */
+  int nByte;                      /* Bytes of space to allocate here */
+  int rc;                         /* value returned by declare_vtab() */
+  Fts3auxTable *p;                /* Virtual table object to return */
+
+  UNUSED_PARAMETER(pUnused);
+
+  /* The user should specify a single argument - the name of an fts3 table. */
+  if( argc!=4 ){
+    *pzErr = sqlite3_mprintf(
+        "wrong number of arguments to fts4aux constructor"
+    );
+    return SQLITE_ERROR;
+  }
+
+  zDb = argv[1]; 
+  nDb = (int)strlen(zDb);
+  zFts3 = argv[3];
+  nFts3 = (int)strlen(zFts3);
+
+  rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
+  if( rc!=SQLITE_OK ) return rc;
+
+  nByte = sizeof(Fts3auxTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
+  p = (Fts3auxTable *)sqlite3_malloc(nByte);
+  if( !p ) return SQLITE_NOMEM;
+  memset(p, 0, nByte);
+
+  p->pFts3Tab = (Fts3Table *)&p[1];
+  p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
+  p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
+  p->pFts3Tab->db = db;
+  p->pFts3Tab->nIndex = 1;
+
+  memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
+  memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
+  sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
+
+  *ppVtab = (sqlite3_vtab *)p;
+  return SQLITE_OK;
+}
+
+/*
+** This function does the work for both the xDisconnect and xDestroy methods.
+** These tables have no persistent representation of their own, so xDisconnect
+** and xDestroy are identical operations.
+*/
+static int fts3auxDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3auxTable *p = (Fts3auxTable *)pVtab;
+  Fts3Table *pFts3 = p->pFts3Tab;
+  int i;
+
+  /* Free any prepared statements held */
+  for(i=0; i<SizeofArray(pFts3->aStmt); i++){
+    sqlite3_finalize(pFts3->aStmt[i]);
+  }
+  sqlite3_free(pFts3->zSegmentsTbl);
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+#define FTS4AUX_EQ_CONSTRAINT 1
+#define FTS4AUX_GE_CONSTRAINT 2
+#define FTS4AUX_LE_CONSTRAINT 4
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3auxBestIndexMethod(
+  sqlite3_vtab *pVTab, 
+  sqlite3_index_info *pInfo
+){
+  int i;
+  int iEq = -1;
+  int iGe = -1;
+  int iLe = -1;
+
+  UNUSED_PARAMETER(pVTab);
+
+  /* This vtab delivers always results in "ORDER BY term ASC" order. */
+  if( pInfo->nOrderBy==1 
+   && pInfo->aOrderBy[0].iColumn==0 
+   && pInfo->aOrderBy[0].desc==0
+  ){
+    pInfo->orderByConsumed = 1;
+  }
+
+  /* Search for equality and range constraints on the "term" column. */
+  for(i=0; i<pInfo->nConstraint; i++){
+    if( pInfo->aConstraint[i].usable && pInfo->aConstraint[i].iColumn==0 ){
+      int op = pInfo->aConstraint[i].op;
+      if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iEq = i;
+      if( op==SQLITE_INDEX_CONSTRAINT_LT ) iLe = i;
+      if( op==SQLITE_INDEX_CONSTRAINT_LE ) iLe = i;
+      if( op==SQLITE_INDEX_CONSTRAINT_GT ) iGe = i;
+      if( op==SQLITE_INDEX_CONSTRAINT_GE ) iGe = i;
+    }
+  }
+
+  if( iEq>=0 ){
+    pInfo->idxNum = FTS4AUX_EQ_CONSTRAINT;
+    pInfo->aConstraintUsage[iEq].argvIndex = 1;
+    pInfo->estimatedCost = 5;
+  }else{
+    pInfo->idxNum = 0;
+    pInfo->estimatedCost = 20000;
+    if( iGe>=0 ){
+      pInfo->idxNum += FTS4AUX_GE_CONSTRAINT;
+      pInfo->aConstraintUsage[iGe].argvIndex = 1;
+      pInfo->estimatedCost /= 2;
+    }
+    if( iLe>=0 ){
+      pInfo->idxNum += FTS4AUX_LE_CONSTRAINT;
+      pInfo->aConstraintUsage[iLe].argvIndex = 1 + (iGe>=0);
+      pInfo->estimatedCost /= 2;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xOpen - Open a cursor.
+*/
+static int fts3auxOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts3auxCursor *pCsr;            /* Pointer to cursor object to return */
+
+  UNUSED_PARAMETER(pVTab);
+
+  pCsr = (Fts3auxCursor *)sqlite3_malloc(sizeof(Fts3auxCursor));
+  if( !pCsr ) return SQLITE_NOMEM;
+  memset(pCsr, 0, sizeof(Fts3auxCursor));
+
+  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** xClose - Close a cursor.
+*/
+static int fts3auxCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+
+  sqlite3Fts3SegmentsClose(pFts3);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  sqlite3_free((void *)pCsr->filter.zTerm);
+  sqlite3_free(pCsr->zStop);
+  sqlite3_free(pCsr->aStat);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+static int fts3auxGrowStatArray(Fts3auxCursor *pCsr, int nSize){
+  if( nSize>pCsr->nStat ){
+    struct Fts3auxColstats *aNew;
+    aNew = (struct Fts3auxColstats *)sqlite3_realloc(pCsr->aStat, 
+        sizeof(struct Fts3auxColstats) * nSize
+    );
+    if( aNew==0 ) return SQLITE_NOMEM;
+    memset(&aNew[pCsr->nStat], 0, 
+        sizeof(struct Fts3auxColstats) * (nSize - pCsr->nStat)
+    );
+    pCsr->aStat = aNew;
+    pCsr->nStat = nSize;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** xNext - Advance the cursor to the next row, if any.
+*/
+static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  int rc;
+
+  /* Increment our pretend rowid value. */
+  pCsr->iRowid++;
+
+  for(pCsr->iCol++; pCsr->iCol<pCsr->nStat; pCsr->iCol++){
+    if( pCsr->aStat[pCsr->iCol].nDoc>0 ) return SQLITE_OK;
+  }
+
+  rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
+  if( rc==SQLITE_ROW ){
+    int i = 0;
+    int nDoclist = pCsr->csr.nDoclist;
+    char *aDoclist = pCsr->csr.aDoclist;
+    int iCol;
+
+    int eState = 0;
+
+    if( pCsr->zStop ){
+      int n = (pCsr->nStop<pCsr->csr.nTerm) ? pCsr->nStop : pCsr->csr.nTerm;
+      int mc = memcmp(pCsr->zStop, pCsr->csr.zTerm, n);
+      if( mc<0 || (mc==0 && pCsr->csr.nTerm>pCsr->nStop) ){
+        pCsr->isEof = 1;
+        return SQLITE_OK;
+      }
+    }
+
+    if( fts3auxGrowStatArray(pCsr, 2) ) return SQLITE_NOMEM;
+    memset(pCsr->aStat, 0, sizeof(struct Fts3auxColstats) * pCsr->nStat);
+    iCol = 0;
+
+    while( i<nDoclist ){
+      sqlite3_int64 v = 0;
+
+      i += sqlite3Fts3GetVarint(&aDoclist[i], &v);
+      switch( eState ){
+        /* State 0. In this state the integer just read was a docid. */
+        case 0:
+          pCsr->aStat[0].nDoc++;
+          eState = 1;
+          iCol = 0;
+          break;
+
+        /* State 1. In this state we are expecting either a 1, indicating
+        ** that the following integer will be a column number, or the
+        ** start of a position list for column 0.  
+        ** 
+        ** The only difference between state 1 and state 2 is that if the
+        ** integer encountered in state 1 is not 0 or 1, then we need to
+        ** increment the column 0 "nDoc" count for this term.
+        */
+        case 1:
+          assert( iCol==0 );
+          if( v>1 ){
+            pCsr->aStat[1].nDoc++;
+          }
+          eState = 2;
+          /* fall through */
+
+        case 2:
+          if( v==0 ){       /* 0x00. Next integer will be a docid. */
+            eState = 0;
+          }else if( v==1 ){ /* 0x01. Next integer will be a column number. */
+            eState = 3;
+          }else{            /* 2 or greater. A position. */
+            pCsr->aStat[iCol+1].nOcc++;
+            pCsr->aStat[0].nOcc++;
+          }
+          break;
+
+        /* State 3. The integer just read is a column number. */
+        default: assert( eState==3 );
+          iCol = (int)v;
+          if( fts3auxGrowStatArray(pCsr, iCol+2) ) return SQLITE_NOMEM;
+          pCsr->aStat[iCol+1].nDoc++;
+          eState = 2;
+          break;
+      }
+    }
+
+    pCsr->iCol = 0;
+    rc = SQLITE_OK;
+  }else{
+    pCsr->isEof = 1;
+  }
+  return rc;
+}
+
+/*
+** xFilter - Initialize a cursor to point at the start of its data.
+*/
+static int fts3auxFilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  int rc;
+  int isScan;
+
+  UNUSED_PARAMETER(nVal);
+  UNUSED_PARAMETER(idxStr);
+
+  assert( idxStr==0 );
+  assert( idxNum==FTS4AUX_EQ_CONSTRAINT || idxNum==0
+       || idxNum==FTS4AUX_LE_CONSTRAINT || idxNum==FTS4AUX_GE_CONSTRAINT
+       || idxNum==(FTS4AUX_LE_CONSTRAINT|FTS4AUX_GE_CONSTRAINT)
+  );
+  isScan = (idxNum!=FTS4AUX_EQ_CONSTRAINT);
+
+  /* In case this cursor is being reused, close and zero it. */
+  testcase(pCsr->filter.zTerm);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  sqlite3_free((void *)pCsr->filter.zTerm);
+  sqlite3_free(pCsr->aStat);
+  memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
+
+  pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+  if( isScan ) pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
+
+  if( idxNum&(FTS4AUX_EQ_CONSTRAINT|FTS4AUX_GE_CONSTRAINT) ){
+    const unsigned char *zStr = sqlite3_value_text(apVal[0]);
+    if( zStr ){
+      pCsr->filter.zTerm = sqlite3_mprintf("%s", zStr);
+      pCsr->filter.nTerm = sqlite3_value_bytes(apVal[0]);
+      if( pCsr->filter.zTerm==0 ) return SQLITE_NOMEM;
+    }
+  }
+  if( idxNum&FTS4AUX_LE_CONSTRAINT ){
+    int iIdx = (idxNum&FTS4AUX_GE_CONSTRAINT) ? 1 : 0;
+    pCsr->zStop = sqlite3_mprintf("%s", sqlite3_value_text(apVal[iIdx]));
+    pCsr->nStop = sqlite3_value_bytes(apVal[iIdx]);
+    if( pCsr->zStop==0 ) return SQLITE_NOMEM;
+  }
+
+  rc = sqlite3Fts3SegReaderCursor(pFts3, 0, 0, FTS3_SEGCURSOR_ALL,
+      pCsr->filter.zTerm, pCsr->filter.nTerm, 0, isScan, &pCsr->csr
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
+  }
+
+  if( rc==SQLITE_OK ) rc = fts3auxNextMethod(pCursor);
+  return rc;
+}
+
+/*
+** xEof - Return true if the cursor is at EOF, or false otherwise.
+*/
+static int fts3auxEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  return pCsr->isEof;
+}
+
+/*
+** xColumn - Return a column value.
+*/
+static int fts3auxColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pContext,      /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts3auxCursor *p = (Fts3auxCursor *)pCursor;
+
+  assert( p->isEof==0 );
+  if( iCol==0 ){        /* Column "term" */
+    sqlite3_result_text(pContext, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
+  }else if( iCol==1 ){  /* Column "col" */
+    if( p->iCol ){
+      sqlite3_result_int(pContext, p->iCol-1);
+    }else{
+      sqlite3_result_text(pContext, "*", -1, SQLITE_STATIC);
+    }
+  }else if( iCol==2 ){  /* Column "documents" */
+    sqlite3_result_int64(pContext, p->aStat[p->iCol].nDoc);
+  }else{                /* Column "occurrences" */
+    sqlite3_result_int64(pContext, p->aStat[p->iCol].nOcc);
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xRowid - Return the current rowid for the cursor.
+*/
+static int fts3auxRowidMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite_int64 *pRowid            /* OUT: Rowid value */
+){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  *pRowid = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Register the fts3aux module with database connection db. Return SQLITE_OK
+** if successful or an error code if sqlite3_create_module() fails.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db){
+  static const sqlite3_module fts3aux_module = {
+     0,                           /* iVersion      */
+     fts3auxConnectMethod,        /* xCreate       */
+     fts3auxConnectMethod,        /* xConnect      */
+     fts3auxBestIndexMethod,      /* xBestIndex    */
+     fts3auxDisconnectMethod,     /* xDisconnect   */
+     fts3auxDisconnectMethod,     /* xDestroy      */
+     fts3auxOpenMethod,           /* xOpen         */
+     fts3auxCloseMethod,          /* xClose        */
+     fts3auxFilterMethod,         /* xFilter       */
+     fts3auxNextMethod,           /* xNext         */
+     fts3auxEofMethod,            /* xEof          */
+     fts3auxColumnMethod,         /* xColumn       */
+     fts3auxRowidMethod,          /* xRowid        */
+     0,                           /* xUpdate       */
+     0,                           /* xBegin        */
+     0,                           /* xSync         */
+     0,                           /* xCommit       */
+     0,                           /* xRollback     */
+     0,                           /* xFindFunction */
+     0,                           /* xRename       */
+     0,                           /* xSavepoint    */
+     0,                           /* xRelease      */
+     0                            /* xRollbackTo   */
+  };
+  int rc;                         /* Return code */
+
+  rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_aux.c ********************************************/
 /************** Begin file fts3_expr.c ***************************************/
 /*
 ** 2008 Nov 28
@@ -96797,8 +121782,7 @@ SQLITE_API int sqlite3_extension_init(
 ** This module contains code that implements a parser for fts3 query strings
 ** (the right-hand argument to the MATCH operator). Because the supported 
 ** syntax is relatively simple, the whole tokenizer/parser system is
-** hand-coded. The public interface to this module is declared in source
-** code file "fts3_expr.h".
+** hand-coded. 
 */
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 
@@ -96824,7 +121808,29 @@ SQLITE_API int sqlite3_extension_init(
 ** to zero causes the module to use the old syntax. If it is set to 
 ** non-zero the new syntax is activated. This is so both syntaxes can
 ** be tested using a single build of testfixture.
+**
+** The following describes the syntax supported by the fts3 MATCH
+** operator in a similar format to that used by the lemon parser
+** generator. This module does not use actually lemon, it uses a
+** custom parser.
+**
+**   query ::= andexpr (OR andexpr)*.
+**
+**   andexpr ::= notexpr (AND? notexpr)*.
+**
+**   notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*.
+**   notexpr ::= LP query RP.
+**
+**   nearexpr ::= phrase (NEAR distance_opt nearexpr)*.
+**
+**   distance_opt ::= .
+**   distance_opt ::= / INTEGER.
+**
+**   phrase ::= TOKEN.
+**   phrase ::= COLUMN:TOKEN.
+**   phrase ::= "TOKEN TOKEN TOKEN...".
 */
+
 #ifdef SQLITE_TEST
 SQLITE_API int sqlite3_fts3_enable_parentheses = 0;
 #else
@@ -96840,13 +121846,26 @@ SQLITE_API int sqlite3_fts3_enable_parentheses = 0;
 */
 #define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10
 
+/* #include <string.h> */
+/* #include <assert.h> */
 
+/*
+** isNot:
+**   This variable is used by function getNextNode(). When getNextNode() is
+**   called, it sets ParseContext.isNot to true if the 'next node' is a 
+**   FTSQUERY_PHRASE with a unary "-" attached to it. i.e. "mysql" in the
+**   FTS3 query "sqlite -mysql". Otherwise, ParseContext.isNot is set to
+**   zero.
+*/
 typedef struct ParseContext ParseContext;
 struct ParseContext {
   sqlite3_tokenizer *pTokenizer;      /* Tokenizer module */
+  int iLangid;                        /* Language id used with tokenizer */
   const char **azCol;                 /* Array of column names for fts3 table */
+  int bFts4;                          /* True to allow FTS4-only syntax */
   int nCol;                           /* Number of entries in azCol[] */
   int iDefaultCol;                    /* Default column to query */
+  int isNot;                          /* True if getNextNode() sees a unary - */
   sqlite3_context *pCtx;              /* Write error message here */
   int nNest;                          /* Number of nested brackets */
 };
@@ -96863,9 +121882,48 @@ struct ParseContext {
 ** negative values).
 */
 static int fts3isspace(char c){
-  return (c&0x80)==0 ? isspace(c) : 0;
+  return c==' ' || c=='\t' || c=='\n' || c=='\r' || c=='\v' || c=='\f';
 }
 
+/*
+** Allocate nByte bytes of memory using sqlite3_malloc(). If successful,
+** zero the memory before returning a pointer to it. If unsuccessful, 
+** return NULL.
+*/
+static void *fts3MallocZero(int nByte){
+  void *pRet = sqlite3_malloc(nByte);
+  if( pRet ) memset(pRet, 0, nByte);
+  return pRet;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(
+  sqlite3_tokenizer *pTokenizer,
+  int iLangid,
+  const char *z,
+  int n,
+  sqlite3_tokenizer_cursor **ppCsr
+){
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCsr = 0;
+  int rc;
+
+  rc = pModule->xOpen(pTokenizer, z, n, &pCsr);
+  assert( rc==SQLITE_OK || pCsr==0 );
+  if( rc==SQLITE_OK ){
+    pCsr->pTokenizer = pTokenizer;
+    if( pModule->iVersion>=1 ){
+      rc = pModule->xLanguageid(pCsr, iLangid);
+      if( rc!=SQLITE_OK ){
+        pModule->xClose(pCsr);
+        pCsr = 0;
+      }
+    }
+  }
+  *ppCsr = pCsr;
+  return rc;
+}
+
+
 /*
 ** Extract the next token from buffer z (length n) using the tokenizer
 ** and other information (column names etc.) in pParse. Create an Fts3Expr
@@ -96892,22 +121950,19 @@ static int getNextToken(
   Fts3Expr *pRet = 0;
   int nConsumed = 0;
 
-  rc = pModule->xOpen(pTokenizer, z, n, &pCursor);
+  rc = sqlite3Fts3OpenTokenizer(pTokenizer, pParse->iLangid, z, n, &pCursor);
   if( rc==SQLITE_OK ){
     const char *zToken;
     int nToken, iStart, iEnd, iPosition;
     int nByte;                               /* total space to allocate */
 
-    pCursor->pTokenizer = pTokenizer;
     rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
-
     if( rc==SQLITE_OK ){
       nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken;
-      pRet = (Fts3Expr *)sqlite3_malloc(nByte);
+      pRet = (Fts3Expr *)fts3MallocZero(nByte);
       if( !pRet ){
         rc = SQLITE_NOMEM;
       }else{
-        memset(pRet, 0, nByte);
         pRet->eType = FTSQUERY_PHRASE;
         pRet->pPhrase = (Fts3Phrase *)&pRet[1];
         pRet->pPhrase->nToken = 1;
@@ -96920,12 +121975,24 @@ static int getNextToken(
           pRet->pPhrase->aToken[0].isPrefix = 1;
           iEnd++;
         }
-        if( !sqlite3_fts3_enable_parentheses && iStart>0 && z[iStart-1]=='-' ){
-          pRet->pPhrase->isNot = 1;
+
+        while( 1 ){
+          if( !sqlite3_fts3_enable_parentheses 
+           && iStart>0 && z[iStart-1]=='-' 
+          ){
+            pParse->isNot = 1;
+            iStart--;
+          }else if( pParse->bFts4 && iStart>0 && z[iStart-1]=='^' ){
+            pRet->pPhrase->aToken[0].bFirst = 1;
+            iStart--;
+          }else{
+            break;
+          }
         }
+
       }
+      nConsumed = iEnd;
     }
-    nConsumed = iEnd;
 
     pModule->xClose(pCursor);
   }
@@ -96940,7 +122007,7 @@ static int getNextToken(
 ** Enlarge a memory allocation.  If an out-of-memory allocation occurs,
 ** then free the old allocation.
 */
-void *fts3ReallocOrFree(void *pOrig, int nNew){
+static void *fts3ReallocOrFree(void *pOrig, int nNew){
   void *pRet = sqlite3_realloc(pOrig, nNew);
   if( !pRet ){
     sqlite3_free(pOrig);
@@ -96973,37 +122040,56 @@ static int getNextString(
   char *zTemp = 0;
   int nTemp = 0;
 
-  rc = pModule->xOpen(pTokenizer, zInput, nInput, &pCursor);
+  const int nSpace = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
+  int nToken = 0;
+
+  /* The final Fts3Expr data structure, including the Fts3Phrase,
+  ** Fts3PhraseToken structures token buffers are all stored as a single 
+  ** allocation so that the expression can be freed with a single call to
+  ** sqlite3_free(). Setting this up requires a two pass approach.
+  **
+  ** The first pass, in the block below, uses a tokenizer cursor to iterate
+  ** through the tokens in the expression. This pass uses fts3ReallocOrFree()
+  ** to assemble data in two dynamic buffers:
+  **
+  **   Buffer p: Points to the Fts3Expr structure, followed by the Fts3Phrase
+  **             structure, followed by the array of Fts3PhraseToken 
+  **             structures. This pass only populates the Fts3PhraseToken array.
+  **
+  **   Buffer zTemp: Contains copies of all tokens.
+  **
+  ** The second pass, in the block that begins "if( rc==SQLITE_DONE )" below,
+  ** appends buffer zTemp to buffer p, and fills in the Fts3Expr and Fts3Phrase
+  ** structures.
+  */
+  rc = sqlite3Fts3OpenTokenizer(
+      pTokenizer, pParse->iLangid, zInput, nInput, &pCursor);
   if( rc==SQLITE_OK ){
     int ii;
-    pCursor->pTokenizer = pTokenizer;
     for(ii=0; rc==SQLITE_OK; ii++){
-      const char *zToken;
-      int nToken, iBegin, iEnd, iPos;
-      rc = pModule->xNext(pCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos);
+      const char *zByte;
+      int nByte, iBegin, iEnd, iPos;
+      rc = pModule->xNext(pCursor, &zByte, &nByte, &iBegin, &iEnd, &iPos);
       if( rc==SQLITE_OK ){
-        int nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
-        p = fts3ReallocOrFree(p, nByte+ii*sizeof(struct PhraseToken));
-        zTemp = fts3ReallocOrFree(zTemp, nTemp + nToken);
-        if( !p || !zTemp ){
-          goto no_mem;
-        }
-        if( ii==0 ){
-          memset(p, 0, nByte);
-          p->pPhrase = (Fts3Phrase *)&p[1];
-          p->eType = FTSQUERY_PHRASE;
-          p->pPhrase->iColumn = pParse->iDefaultCol;
-        }
-        p->pPhrase = (Fts3Phrase *)&p[1];
-        p->pPhrase->nToken = ii+1;
-        p->pPhrase->aToken[ii].n = nToken;
-        memcpy(&zTemp[nTemp], zToken, nToken);
-        nTemp += nToken;
-        if( iEnd<nInput && zInput[iEnd]=='*' ){
-          p->pPhrase->aToken[ii].isPrefix = 1;
-        }else{
-          p->pPhrase->aToken[ii].isPrefix = 0;
-        }
+        Fts3PhraseToken *pToken;
+
+        p = fts3ReallocOrFree(p, nSpace + ii*sizeof(Fts3PhraseToken));
+        if( !p ) goto no_mem;
+
+        zTemp = fts3ReallocOrFree(zTemp, nTemp + nByte);
+        if( !zTemp ) goto no_mem;
+
+        assert( nToken==ii );
+        pToken = &((Fts3Phrase *)(&p[1]))->aToken[ii];
+        memset(pToken, 0, sizeof(Fts3PhraseToken));
+
+        memcpy(&zTemp[nTemp], zByte, nByte);
+        nTemp += nByte;
+
+        pToken->n = nByte;
+        pToken->isPrefix = (iEnd<nInput && zInput[iEnd]=='*');
+        pToken->bFirst = (iBegin>0 && zInput[iBegin-1]=='^');
+        nToken = ii+1;
       }
     }
 
@@ -97013,22 +122099,28 @@ static int getNextString(
 
   if( rc==SQLITE_DONE ){
     int jj;
-    char *zNew;
-    int nNew = 0;
-    int nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
-    nByte += (p->pPhrase->nToken-1) * sizeof(struct PhraseToken);
-    p = fts3ReallocOrFree(p, nByte + nTemp);
-    if( !p ){
-      goto no_mem;
-    }
+    char *zBuf = 0;
+
+    p = fts3ReallocOrFree(p, nSpace + nToken*sizeof(Fts3PhraseToken) + nTemp);
+    if( !p ) goto no_mem;
+    memset(p, 0, (char *)&(((Fts3Phrase *)&p[1])->aToken[0])-(char *)p);
+    p->eType = FTSQUERY_PHRASE;
     p->pPhrase = (Fts3Phrase *)&p[1];
-    zNew = &(((char *)p)[nByte]);
-    memcpy(zNew, zTemp, nTemp);
-    for(jj=0; jj<p->pPhrase->nToken; jj++){
-      p->pPhrase->aToken[jj].z = &zNew[nNew];
-      nNew += p->pPhrase->aToken[jj].n;
+    p->pPhrase->iColumn = pParse->iDefaultCol;
+    p->pPhrase->nToken = nToken;
+
+    zBuf = (char *)&p->pPhrase->aToken[nToken];
+    if( zTemp ){
+      memcpy(zBuf, zTemp, nTemp);
+      sqlite3_free(zTemp);
+    }else{
+      assert( nTemp==0 );
+    }
+
+    for(jj=0; jj<p->pPhrase->nToken; jj++){
+      p->pPhrase->aToken[jj].z = zBuf;
+      zBuf += p->pPhrase->aToken[jj].n;
     }
-    sqlite3_free(zTemp);
     rc = SQLITE_OK;
   }
 
@@ -97066,7 +122158,7 @@ static int getNextNode(
   int *pnConsumed                         /* OUT: Number of bytes consumed */
 ){
   static const struct Fts3Keyword {
-    char z[4];                            /* Keyword text */
+    char *z;                              /* Keyword text */
     unsigned char n;                      /* Length of the keyword */
     unsigned char parenOnly;              /* Only valid in paren mode */
     unsigned char eType;                  /* Keyword code */
@@ -97085,6 +122177,8 @@ static int getNextNode(
   const char *zInput = z;
   int nInput = n;
 
+  pParse->isNot = 0;
+
   /* Skip over any whitespace before checking for a keyword, an open or
   ** close bracket, or a quoted string. 
   */
@@ -97128,12 +122222,14 @@ static int getNextNode(
       if( fts3isspace(cNext) 
        || cNext=='"' || cNext=='(' || cNext==')' || cNext==0
       ){
-        pRet = (Fts3Expr *)sqlite3_malloc(sizeof(Fts3Expr));
-        memset(pRet, 0, sizeof(Fts3Expr));
+        pRet = (Fts3Expr *)fts3MallocZero(sizeof(Fts3Expr));
+        if( !pRet ){
+          return SQLITE_NOMEM;
+        }
         pRet->eType = pKey->eType;
         pRet->nNear = nNear;
         *ppExpr = pRet;
-        *pnConsumed = (zInput - z) + nKey;
+        *pnConsumed = (int)((zInput - z) + nKey);
         return SQLITE_OK;
       }
 
@@ -97147,20 +122243,19 @@ static int getNextNode(
   if( sqlite3_fts3_enable_parentheses ){
     if( *zInput=='(' ){
       int nConsumed;
-      int rc;
       pParse->nNest++;
       rc = fts3ExprParse(pParse, &zInput[1], nInput-1, ppExpr, &nConsumed);
       if( rc==SQLITE_OK && !*ppExpr ){
         rc = SQLITE_DONE;
       }
-      *pnConsumed = (zInput - z) + 1 + nConsumed;
+      *pnConsumed = (int)((zInput - z) + 1 + nConsumed);
       return rc;
     }
   
     /* Check for a close bracket. */
     if( *zInput==')' ){
       pParse->nNest--;
-      *pnConsumed = (zInput - z) + 1;
+      *pnConsumed = (int)((zInput - z) + 1);
       return SQLITE_DONE;
     }
   }
@@ -97172,7 +122267,7 @@ static int getNextNode(
   */
   if( *zInput=='"' ){
     for(ii=1; ii<nInput && zInput[ii]!='"'; ii++);
-    *pnConsumed = (zInput - z) + ii + 1;
+    *pnConsumed = (int)((zInput - z) + ii + 1);
     if( ii==nInput ){
       return SQLITE_ERROR;
     }
@@ -97195,10 +122290,12 @@ static int getNextNode(
   iColLen = 0;
   for(ii=0; ii<pParse->nCol; ii++){
     const char *zStr = pParse->azCol[ii];
-    int nStr = strlen(zStr);
-    if( nInput>nStr && zInput[nStr]==':' && memcmp(zStr, zInput, nStr)==0 ){
+    int nStr = (int)strlen(zStr);
+    if( nInput>nStr && zInput[nStr]==':' 
+     && sqlite3_strnicmp(zStr, zInput, nStr)==0 
+    ){
       iCol = ii;
-      iColLen = ((zInput - z) + nStr + 1);
+      iColLen = (int)((zInput - z) + nStr + 1);
       break;
     }
   }
@@ -97300,26 +122397,24 @@ static int fts3ExprParse(
       int isPhrase;
 
       if( !sqlite3_fts3_enable_parentheses 
-       && p->eType==FTSQUERY_PHRASE && p->pPhrase->isNot 
+       && p->eType==FTSQUERY_PHRASE && pParse->isNot 
       ){
         /* Create an implicit NOT operator. */
-        Fts3Expr *pNot = sqlite3_malloc(sizeof(Fts3Expr));
+        Fts3Expr *pNot = fts3MallocZero(sizeof(Fts3Expr));
         if( !pNot ){
           sqlite3Fts3ExprFree(p);
           rc = SQLITE_NOMEM;
           goto exprparse_out;
         }
-        memset(pNot, 0, sizeof(Fts3Expr));
         pNot->eType = FTSQUERY_NOT;
         pNot->pRight = p;
         if( pNotBranch ){
-          pNotBranch->pLeft = p;
-          pNot->pRight = pNotBranch;
+          pNot->pLeft = pNotBranch;
         }
         pNotBranch = pNot;
+        p = pPrev;
       }else{
         int eType = p->eType;
-        assert( eType!=FTSQUERY_PHRASE || !p->pPhrase->isNot );
         isPhrase = (eType==FTSQUERY_PHRASE || p->pLeft);
 
         /* The isRequirePhrase variable is set to true if a phrase or
@@ -97337,13 +122432,12 @@ static int fts3ExprParse(
           /* Insert an implicit AND operator. */
           Fts3Expr *pAnd;
           assert( pRet && pPrev );
-          pAnd = sqlite3_malloc(sizeof(Fts3Expr));
+          pAnd = fts3MallocZero(sizeof(Fts3Expr));
           if( !pAnd ){
             sqlite3Fts3ExprFree(p);
             rc = SQLITE_NOMEM;
             goto exprparse_out;
           }
-          memset(pAnd, 0, sizeof(Fts3Expr));
           pAnd->eType = FTSQUERY_AND;
           insertBinaryOperator(&pRet, pPrev, pAnd);
           pPrev = pAnd;
@@ -97398,7 +122492,11 @@ static int fts3ExprParse(
       if( !pRet ){
         rc = SQLITE_ERROR;
       }else{
-        pNotBranch->pLeft = pRet;
+        Fts3Expr *pIter = pNotBranch;
+        while( pIter->pLeft ){
+          pIter = pIter->pLeft;
+        }
+        pIter->pLeft = pRet;
         pRet = pNotBranch;
       }
     }
@@ -97441,7 +122539,9 @@ exprparse_out:
 */
 SQLITE_PRIVATE int sqlite3Fts3ExprParse(
   sqlite3_tokenizer *pTokenizer,      /* Tokenizer module */
+  int iLangid,                        /* Language id for tokenizer */
   char **azCol,                       /* Array of column names for fts3 table */
+  int bFts4,                          /* True to allow FTS4-only syntax */
   int nCol,                           /* Number of entries in azCol[] */
   int iDefaultCol,                    /* Default column to query */
   const char *z, int n,               /* Text of MATCH query */
@@ -97450,17 +122550,20 @@ SQLITE_PRIVATE int sqlite3Fts3ExprParse(
   int nParsed;
   int rc;
   ParseContext sParse;
+
+  memset(&sParse, 0, sizeof(ParseContext));
   sParse.pTokenizer = pTokenizer;
+  sParse.iLangid = iLangid;
   sParse.azCol = (const char **)azCol;
   sParse.nCol = nCol;
   sParse.iDefaultCol = iDefaultCol;
-  sParse.nNest = 0;
+  sParse.bFts4 = bFts4;
   if( z==0 ){
     *ppExpr = 0;
     return SQLITE_OK;
   }
   if( n<0 ){
-    n = strlen(z);
+    n = (int)strlen(z);
   }
   rc = fts3ExprParse(&sParse, z, n, ppExpr, &nParsed);
 
@@ -97479,8 +122582,11 @@ SQLITE_PRIVATE int sqlite3Fts3ExprParse(
 */
 SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *p){
   if( p ){
+    assert( p->eType==FTSQUERY_PHRASE || p->pPhrase==0 );
     sqlite3Fts3ExprFree(p->pLeft);
     sqlite3Fts3ExprFree(p->pRight);
+    sqlite3Fts3EvalPhraseCleanup(p->pPhrase);
+    sqlite3_free(p->aMI);
     sqlite3_free(p);
   }
 }
@@ -97492,6 +122598,7 @@ SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *p){
 
 #ifdef SQLITE_TEST
 
+/* #include <stdio.h> */
 
 /*
 ** Function to query the hash-table of tokenizers (see README.tokenizers).
@@ -97514,7 +122621,7 @@ static int queryTestTokenizer(
   sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
   if( SQLITE_ROW==sqlite3_step(pStmt) ){
     if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){
-      memcpy(pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
+      memcpy((void *)pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
     }
   }
 
@@ -97522,47 +122629,53 @@ static int queryTestTokenizer(
 }
 
 /*
-** This function is part of the test interface for the query parser. It
-** writes a text representation of the query expression pExpr into the
-** buffer pointed to by argument zBuf. It is assumed that zBuf is large 
-** enough to store the required text representation.
+** Return a pointer to a buffer containing a text representation of the
+** expression passed as the first argument. The buffer is obtained from
+** sqlite3_malloc(). It is the responsibility of the caller to use 
+** sqlite3_free() to release the memory. If an OOM condition is encountered,
+** NULL is returned.
+**
+** If the second argument is not NULL, then its contents are prepended to 
+** the returned expression text and then freed using sqlite3_free().
 */
-static void exprToString(Fts3Expr *pExpr, char *zBuf){
+static char *exprToString(Fts3Expr *pExpr, char *zBuf){
   switch( pExpr->eType ){
     case FTSQUERY_PHRASE: {
       Fts3Phrase *pPhrase = pExpr->pPhrase;
       int i;
-      zBuf += sprintf(zBuf, "PHRASE %d %d", pPhrase->iColumn, pPhrase->isNot);
-      for(i=0; i<pPhrase->nToken; i++){
-        zBuf += sprintf(zBuf," %.*s",pPhrase->aToken[i].n,pPhrase->aToken[i].z);
-        zBuf += sprintf(zBuf,"%s", (pPhrase->aToken[i].isPrefix?"+":""));
+      zBuf = sqlite3_mprintf(
+          "%zPHRASE %d 0", zBuf, pPhrase->iColumn);
+      for(i=0; zBuf && i<pPhrase->nToken; i++){
+        zBuf = sqlite3_mprintf("%z %.*s%s", zBuf, 
+            pPhrase->aToken[i].n, pPhrase->aToken[i].z,
+            (pPhrase->aToken[i].isPrefix?"+":"")
+        );
       }
-      return;
+      return zBuf;
     }
 
     case FTSQUERY_NEAR:
-      zBuf += sprintf(zBuf, "NEAR/%d ", pExpr->nNear);
+      zBuf = sqlite3_mprintf("%zNEAR/%d ", zBuf, pExpr->nNear);
       break;
     case FTSQUERY_NOT:
-      zBuf += sprintf(zBuf, "NOT ");
+      zBuf = sqlite3_mprintf("%zNOT ", zBuf);
       break;
     case FTSQUERY_AND:
-      zBuf += sprintf(zBuf, "AND ");
+      zBuf = sqlite3_mprintf("%zAND ", zBuf);
       break;
     case FTSQUERY_OR:
-      zBuf += sprintf(zBuf, "OR ");
+      zBuf = sqlite3_mprintf("%zOR ", zBuf);
       break;
   }
 
-  zBuf += sprintf(zBuf, "{");
-  exprToString(pExpr->pLeft, zBuf);
-  zBuf += strlen(zBuf);
-  zBuf += sprintf(zBuf, "} ");
+  if( zBuf ) zBuf = sqlite3_mprintf("%z{", zBuf);
+  if( zBuf ) zBuf = exprToString(pExpr->pLeft, zBuf);
+  if( zBuf ) zBuf = sqlite3_mprintf("%z} {", zBuf);
 
-  zBuf += sprintf(zBuf, "{");
-  exprToString(pExpr->pRight, zBuf);
-  zBuf += strlen(zBuf);
-  zBuf += sprintf(zBuf, "}");
+  if( zBuf ) zBuf = exprToString(pExpr->pRight, zBuf);
+  if( zBuf ) zBuf = sqlite3_mprintf("%z}", zBuf);
+
+  return zBuf;
 }
 
 /*
@@ -97593,6 +122706,7 @@ static void fts3ExprTest(
   int nCol;
   int ii;
   Fts3Expr *pExpr;
+  char *zBuf = 0;
   sqlite3 *db = sqlite3_context_db_handle(context);
 
   if( argc<3 ){
@@ -97633,20 +122747,19 @@ static void fts3ExprTest(
   }
 
   rc = sqlite3Fts3ExprParse(
-      pTokenizer, azCol, nCol, nCol, zExpr, nExpr, &pExpr
+      pTokenizer, 0, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr
   );
-  if( rc==SQLITE_NOMEM ){
-    sqlite3_result_error_nomem(context);
-    goto exprtest_out;
-  }else if( rc==SQLITE_OK ){
-    char zBuf[4096];
-    exprToString(pExpr, zBuf);
-    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
-    sqlite3Fts3ExprFree(pExpr);
-  }else{
+  if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){
     sqlite3_result_error(context, "Error parsing expression", -1);
+  }else if( rc==SQLITE_NOMEM || !(zBuf = exprToString(pExpr, 0)) ){
+    sqlite3_result_error_nomem(context);
+  }else{
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+    sqlite3_free(zBuf);
   }
 
+  sqlite3Fts3ExprFree(pExpr);
+
 exprtest_out:
   if( pModule && pTokenizer ){
     rc = pModule->xDestroy(pTokenizer);
@@ -97658,8 +122771,8 @@ exprtest_out:
 ** Register the query expression parser test function fts3_exprtest() 
 ** with database connection db. 
 */
-SQLITE_PRIVATE void sqlite3Fts3ExprInitTestInterface(sqlite3* db){
-  sqlite3_create_function(
+SQLITE_PRIVATE int sqlite3Fts3ExprInitTestInterface(sqlite3* db){
+  return sqlite3_create_function(
       db, "fts3_exprtest", -1, SQLITE_UTF8, 0, fts3ExprTest, 0, 0
   );
 }
@@ -97696,6 +122809,9 @@ SQLITE_PRIVATE void sqlite3Fts3ExprInitTestInterface(sqlite3* db){
 */
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <string.h> */
 
 
 /*
@@ -97722,7 +122838,7 @@ static void fts3HashFree(void *p){
 ** true if the hash table should make its own private copy of keys and
 ** false if it should just use the supplied pointer.
 */
-SQLITE_PRIVATE void sqlite3Fts3HashInit(fts3Hash *pNew, int keyClass, int copyKey){
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey){
   assert( pNew!=0 );
   assert( keyClass>=FTS3_HASH_STRING && keyClass<=FTS3_HASH_BINARY );
   pNew->keyClass = keyClass;
@@ -97737,8 +122853,8 @@ SQLITE_PRIVATE void sqlite3Fts3HashInit(fts3Hash *pNew, int keyClass, int copyKe
 ** Call this routine to delete a hash table or to reset a hash table
 ** to the empty state.
 */
-SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash *pH){
-  fts3HashElem *elem;         /* For looping over all elements of the table */
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash *pH){
+  Fts3HashElem *elem;         /* For looping over all elements of the table */
 
   assert( pH!=0 );
   elem = pH->first;
@@ -97747,7 +122863,7 @@ SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash *pH){
   pH->ht = 0;
   pH->htsize = 0;
   while( elem ){
-    fts3HashElem *next_elem = elem->next;
+    Fts3HashElem *next_elem = elem->next;
     if( pH->copyKey && elem->pKey ){
       fts3HashFree(elem->pKey);
     }
@@ -97830,11 +122946,11 @@ static int (*ftsCompareFunction(int keyClass))(const void*,int,const void*,int){
 /* Link an element into the hash table
 */
 static void fts3HashInsertElement(
-  fts3Hash *pH,            /* The complete hash table */
+  Fts3Hash *pH,            /* The complete hash table */
   struct _fts3ht *pEntry,  /* The entry into which pNew is inserted */
-  fts3HashElem *pNew       /* The element to be inserted */
+  Fts3HashElem *pNew       /* The element to be inserted */
 ){
-  fts3HashElem *pHead;     /* First element already in pEntry */
+  Fts3HashElem *pHead;     /* First element already in pEntry */
   pHead = pEntry->chain;
   if( pHead ){
     pNew->next = pHead;
@@ -97856,15 +122972,17 @@ static void fts3HashInsertElement(
 /* Resize the hash table so that it cantains "new_size" buckets.
 ** "new_size" must be a power of 2.  The hash table might fail 
 ** to resize if sqliteMalloc() fails.
+**
+** Return non-zero if a memory allocation error occurs.
 */
-static void fts3Rehash(fts3Hash *pH, int new_size){
+static int fts3Rehash(Fts3Hash *pH, int new_size){
   struct _fts3ht *new_ht;          /* The new hash table */
-  fts3HashElem *elem, *next_elem;  /* For looping over existing elements */
+  Fts3HashElem *elem, *next_elem;  /* For looping over existing elements */
   int (*xHash)(const void*,int);   /* The hash function */
 
   assert( (new_size & (new_size-1))==0 );
   new_ht = (struct _fts3ht *)fts3HashMalloc( new_size*sizeof(struct _fts3ht) );
-  if( new_ht==0 ) return;
+  if( new_ht==0 ) return 1;
   fts3HashFree(pH->ht);
   pH->ht = new_ht;
   pH->htsize = new_size;
@@ -97874,19 +122992,20 @@ static void fts3Rehash(fts3Hash *pH, int new_size){
     next_elem = elem->next;
     fts3HashInsertElement(pH, &new_ht[h], elem);
   }
+  return 0;
 }
 
 /* This function (for internal use only) locates an element in an
 ** hash table that matches the given key.  The hash for this key has
 ** already been computed and is passed as the 4th parameter.
 */
-static fts3HashElem *fts3FindElementByHash(
-  const fts3Hash *pH, /* The pH to be searched */
+static Fts3HashElem *fts3FindElementByHash(
+  const Fts3Hash *pH, /* The pH to be searched */
   const void *pKey,   /* The key we are searching for */
   int nKey,
   int h               /* The hash for this key. */
 ){
-  fts3HashElem *elem;            /* Used to loop thru the element list */
+  Fts3HashElem *elem;            /* Used to loop thru the element list */
   int count;                     /* Number of elements left to test */
   int (*xCompare)(const void*,int,const void*,int);  /* comparison function */
 
@@ -97909,8 +123028,8 @@ static fts3HashElem *fts3FindElementByHash(
 ** element and a hash on the element's key.
 */
 static void fts3RemoveElementByHash(
-  fts3Hash *pH,         /* The pH containing "elem" */
-  fts3HashElem* elem,   /* The element to be removed from the pH */
+  Fts3Hash *pH,         /* The pH containing "elem" */
+  Fts3HashElem* elem,   /* The element to be removed from the pH */
   int h                 /* Hash value for the element */
 ){
   struct _fts3ht *pEntry;
@@ -97942,13 +123061,12 @@ static void fts3RemoveElementByHash(
   }
 }
 
-/* Attempt to locate an element of the hash table pH with a key
-** that matches pKey,nKey.  Return the data for this element if it is
-** found, or NULL if there is no match.
-*/
-SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash *pH, const void *pKey, int nKey){
-  int h;                 /* A hash on key */
-  fts3HashElem *elem;    /* The element that matches key */
+SQLITE_PRIVATE Fts3HashElem *sqlite3Fts3HashFindElem(
+  const Fts3Hash *pH, 
+  const void *pKey, 
+  int nKey
+){
+  int h;                          /* A hash on key */
   int (*xHash)(const void*,int);  /* The hash function */
 
   if( pH==0 || pH->ht==0 ) return 0;
@@ -97956,8 +123074,19 @@ SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash *pH, const void *pKey, i
   assert( xHash!=0 );
   h = (*xHash)(pKey,nKey);
   assert( (pH->htsize & (pH->htsize-1))==0 );
-  elem = fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
-  return elem ? elem->data : 0;
+  return fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
+}
+
+/* 
+** Attempt to locate an element of the hash table pH with a key
+** that matches pKey,nKey.  Return the data for this element if it is
+** found, or NULL if there is no match.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash *pH, const void *pKey, int nKey){
+  Fts3HashElem *pElem;            /* The element that matches key (if any) */
+
+  pElem = sqlite3Fts3HashFindElem(pH, pKey, nKey);
+  return pElem ? pElem->data : 0;
 }
 
 /* Insert an element into the hash table pH.  The key is pKey,nKey
@@ -97976,15 +123105,15 @@ SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash *pH, const void *pKey, i
 ** element corresponding to "key" is removed from the hash table.
 */
 SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
-  fts3Hash *pH,        /* The hash table to insert into */
+  Fts3Hash *pH,        /* The hash table to insert into */
   const void *pKey,    /* The key */
   int nKey,            /* Number of bytes in the key */
   void *data           /* The data */
 ){
   int hraw;                 /* Raw hash value of the key */
   int h;                    /* the hash of the key modulo hash table size */
-  fts3HashElem *elem;       /* Used to loop thru the element list */
-  fts3HashElem *new_elem;   /* New element added to the pH */
+  Fts3HashElem *elem;       /* Used to loop thru the element list */
+  Fts3HashElem *new_elem;   /* New element added to the pH */
   int (*xHash)(const void*,int);  /* The hash function */
 
   assert( pH!=0 );
@@ -98004,14 +123133,14 @@ SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
     return old_data;
   }
   if( data==0 ) return 0;
-  if( pH->htsize==0 ){
-    fts3Rehash(pH,8);
-    if( pH->htsize==0 ){
-      pH->count = 0;
-      return data;
-    }
+  if( (pH->htsize==0 && fts3Rehash(pH,8))
+   || (pH->count>=pH->htsize && fts3Rehash(pH, pH->htsize*2))
+  ){
+    pH->count = 0;
+    return data;
   }
-  new_elem = (fts3HashElem*)fts3HashMalloc( sizeof(fts3HashElem) );
+  assert( pH->htsize>0 );
+  new_elem = (Fts3HashElem*)fts3HashMalloc( sizeof(Fts3HashElem) );
   if( new_elem==0 ) return data;
   if( pH->copyKey && pKey!=0 ){
     new_elem->pKey = fts3HashMalloc( nKey );
@@ -98025,9 +123154,6 @@ SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
   }
   new_elem->nKey = nKey;
   pH->count++;
-  if( pH->count > pH->htsize ){
-    fts3Rehash(pH,pH->htsize*2);
-  }
   assert( pH->htsize>0 );
   assert( (pH->htsize & (pH->htsize-1))==0 );
   h = hraw & (pH->htsize-1);
@@ -98066,7 +123192,10 @@ SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
 */
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 
-
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
 
 
 /*
@@ -98077,7 +123206,7 @@ typedef struct porter_tokenizer {
 } porter_tokenizer;
 
 /*
-** Class derived from sqlit3_tokenizer_cursor
+** Class derived from sqlite3_tokenizer_cursor
 */
 typedef struct porter_tokenizer_cursor {
   sqlite3_tokenizer_cursor base;
@@ -98090,10 +123219,6 @@ typedef struct porter_tokenizer_cursor {
 } porter_tokenizer_cursor;
 
 
-/* Forward declaration */
-static const sqlite3_tokenizer_module porterTokenizerModule;
-
-
 /*
 ** Create a new tokenizer instance.
 */
@@ -98102,6 +123227,10 @@ static int porterCreate(
   sqlite3_tokenizer **ppTokenizer
 ){
   porter_tokenizer *t;
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
   t = (porter_tokenizer *) sqlite3_malloc(sizeof(*t));
   if( t==NULL ) return SQLITE_NOMEM;
   memset(t, 0, sizeof(*t));
@@ -98130,6 +123259,8 @@ static int porterOpen(
 ){
   porter_tokenizer_cursor *c;
 
+  UNUSED_PARAMETER(pTokenizer);
+
   c = (porter_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
   if( c==NULL ) return SQLITE_NOMEM;
 
@@ -98270,7 +123401,7 @@ static int hasVowel(const char *z){
 ** the first two characters of z[].
 */
 static int doubleConsonant(const char *z){
-  return isConsonant(z) && z[0]==z[1] && isConsonant(z+1);
+  return isConsonant(z) && z[0]==z[1];
 }
 
 /*
@@ -98283,10 +123414,10 @@ static int doubleConsonant(const char *z){
 */
 static int star_oh(const char *z){
   return
-    z[0]!=0 && isConsonant(z) &&
+    isConsonant(z) &&
     z[0]!='w' && z[0]!='x' && z[0]!='y' &&
-    z[1]!=0 && isVowel(z+1) &&
-    z[2]!=0 && isConsonant(z+2);
+    isVowel(z+1) &&
+    isConsonant(z+2);
 }
 
 /*
@@ -98330,7 +123461,7 @@ static void copy_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
   int i, mx, j;
   int hasDigit = 0;
   for(i=0; i<nIn; i++){
-    int c = zIn[i];
+    char c = zIn[i];
     if( c>='A' && c<='Z' ){
       zOut[i] = c - 'A' + 'a';
     }else{
@@ -98374,17 +123505,17 @@ static void copy_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
 ** no chance of overflowing the zOut buffer.
 */
 static void porter_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
-  int i, j, c;
+  int i, j;
   char zReverse[28];
   char *z, *z2;
-  if( nIn<3 || nIn>=sizeof(zReverse)-7 ){
+  if( nIn<3 || nIn>=(int)sizeof(zReverse)-7 ){
     /* The word is too big or too small for the porter stemmer.
     ** Fallback to the copy stemmer */
     copy_stemmer(zIn, nIn, zOut, pnOut);
     return;
   }
   for(i=0, j=sizeof(zReverse)-6; i<nIn; i++, j--){
-    c = zIn[i];
+    char c = zIn[i];
     if( c>='A' && c<='Z' ){
       zReverse[j] = c + 'a' - 'A';
     }else if( c>='a' && c<='z' ){
@@ -98583,7 +123714,7 @@ static void porter_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
   /* z[] is now the stemmed word in reverse order.  Flip it back
   ** around into forward order and return.
   */
-  *pnOut = i = strlen(z);
+  *pnOut = i = (int)strlen(z);
   zOut[i] = 0;
   while( *z ){
     zOut[--i] = *(z++);
@@ -98638,9 +123769,11 @@ static int porterNext(
     if( c->iOffset>iStartOffset ){
       int n = c->iOffset-iStartOffset;
       if( n>c->nAllocated ){
+        char *pNew;
         c->nAllocated = n+20;
-        c->zToken = sqlite3_realloc(c->zToken, c->nAllocated);
-        if( c->zToken==NULL ) return SQLITE_NOMEM;
+        pNew = sqlite3_realloc(c->zToken, c->nAllocated);
+        if( !pNew ) return SQLITE_NOMEM;
+        c->zToken = pNew;
       }
       porter_stemmer(&z[iStartOffset], n, c->zToken, pnBytes);
       *pzToken = c->zToken;
@@ -98663,6 +123796,7 @@ static const sqlite3_tokenizer_module porterTokenizerModule = {
   porterOpen,
   porterClose,
   porterNext,
+  0
 };
 
 /*
@@ -98706,10 +123840,8 @@ SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(
 */
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 
-#ifndef SQLITE_CORE
-  SQLITE_EXTENSION_INIT1
-#endif
-
+/* #include <assert.h> */
+/* #include <string.h> */
 
 /*
 ** Implementation of the SQL scalar function for accessing the underlying 
@@ -98736,14 +123868,14 @@ static void scalarFunc(
   int argc,
   sqlite3_value **argv
 ){
-  fts3Hash *pHash;
+  Fts3Hash *pHash;
   void *pPtr = 0;
   const unsigned char *zName;
   int nName;
 
   assert( argc==1 || argc==2 );
 
-  pHash = (fts3Hash *)sqlite3_user_data(context);
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
 
   zName = sqlite3_value_text(argv[0]);
   nName = sqlite3_value_bytes(argv[0])+1;
@@ -98774,16 +123906,126 @@ static void scalarFunc(
   sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
 }
 
+SQLITE_PRIVATE int sqlite3Fts3IsIdChar(char c){
+  static const char isFtsIdChar[] = {
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 0x */
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 1x */
+      0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+  };
+  return (c&0x80 || isFtsIdChar[(int)(c)]);
+}
+
+SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *zStr, int *pn){
+  const char *z1;
+  const char *z2 = 0;
+
+  /* Find the start of the next token. */
+  z1 = zStr;
+  while( z2==0 ){
+    char c = *z1;
+    switch( c ){
+      case '\0': return 0;        /* No more tokens here */
+      case '\'':
+      case '"':
+      case '`': {
+        z2 = z1;
+        while( *++z2 && (*z2!=c || *++z2==c) );
+        break;
+      }
+      case '[':
+        z2 = &z1[1];
+        while( *z2 && z2[0]!=']' ) z2++;
+        if( *z2 ) z2++;
+        break;
+
+      default:
+        if( sqlite3Fts3IsIdChar(*z1) ){
+          z2 = &z1[1];
+          while( sqlite3Fts3IsIdChar(*z2) ) z2++;
+        }else{
+          z1++;
+        }
+    }
+  }
+
+  *pn = (int)(z2-z1);
+  return z1;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(
+  Fts3Hash *pHash,                /* Tokenizer hash table */
+  const char *zArg,               /* Tokenizer name */
+  sqlite3_tokenizer **ppTok,      /* OUT: Tokenizer (if applicable) */
+  char **pzErr                    /* OUT: Set to malloced error message */
+){
+  int rc;
+  char *z = (char *)zArg;
+  int n = 0;
+  char *zCopy;
+  char *zEnd;                     /* Pointer to nul-term of zCopy */
+  sqlite3_tokenizer_module *m;
+
+  zCopy = sqlite3_mprintf("%s", zArg);
+  if( !zCopy ) return SQLITE_NOMEM;
+  zEnd = &zCopy[strlen(zCopy)];
+
+  z = (char *)sqlite3Fts3NextToken(zCopy, &n);
+  z[n] = '\0';
+  sqlite3Fts3Dequote(z);
+
+  m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash,z,(int)strlen(z)+1);
+  if( !m ){
+    *pzErr = sqlite3_mprintf("unknown tokenizer: %s", z);
+    rc = SQLITE_ERROR;
+  }else{
+    char const **aArg = 0;
+    int iArg = 0;
+    z = &z[n+1];
+    while( z<zEnd && (NULL!=(z = (char *)sqlite3Fts3NextToken(z, &n))) ){
+      int nNew = sizeof(char *)*(iArg+1);
+      char const **aNew = (const char **)sqlite3_realloc((void *)aArg, nNew);
+      if( !aNew ){
+        sqlite3_free(zCopy);
+        sqlite3_free((void *)aArg);
+        return SQLITE_NOMEM;
+      }
+      aArg = aNew;
+      aArg[iArg++] = z;
+      z[n] = '\0';
+      sqlite3Fts3Dequote(z);
+      z = &z[n+1];
+    }
+    rc = m->xCreate(iArg, aArg, ppTok);
+    assert( rc!=SQLITE_OK || *ppTok );
+    if( rc!=SQLITE_OK ){
+      *pzErr = sqlite3_mprintf("unknown tokenizer");
+    }else{
+      (*ppTok)->pModule = m; 
+    }
+    sqlite3_free((void *)aArg);
+  }
+
+  sqlite3_free(zCopy);
+  return rc;
+}
+
+
 #ifdef SQLITE_TEST
 
+/* #include <tcl.h> */
+/* #include <string.h> */
 
 /*
 ** Implementation of a special SQL scalar function for testing tokenizers 
 ** designed to be used in concert with the Tcl testing framework. This
-** function must be called with two arguments:
+** function must be called with two or more arguments:
 **
-**   SELECT <function-name>(<key-name>, <input-string>);
-**   SELECT <function-name>(<key-name>, <pointer>);
+**   SELECT <function-name>(<key-name>, ..., <input-string>);
 **
 ** where <function-name> is the name passed as the second argument
 ** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer')
@@ -98808,7 +124050,7 @@ static void testFunc(
   int argc,
   sqlite3_value **argv
 ){
-  fts3Hash *pHash;
+  Fts3Hash *pHash;
   sqlite3_tokenizer_module *p;
   sqlite3_tokenizer *pTokenizer = 0;
   sqlite3_tokenizer_cursor *pCsr = 0;
@@ -98820,28 +124062,28 @@ static void testFunc(
   const char *zInput;
   int nInput;
 
-  const char *zArg = 0;
+  const char *azArg[64];
 
   const char *zToken;
   int nToken;
   int iStart;
   int iEnd;
   int iPos;
+  int i;
 
   Tcl_Obj *pRet;
 
-  assert( argc==2 || argc==3 );
+  if( argc<2 ){
+    sqlite3_result_error(context, "insufficient arguments", -1);
+    return;
+  }
 
   nName = sqlite3_value_bytes(argv[0]);
   zName = (const char *)sqlite3_value_text(argv[0]);
   nInput = sqlite3_value_bytes(argv[argc-1]);
   zInput = (const char *)sqlite3_value_text(argv[argc-1]);
 
-  if( argc==3 ){
-    zArg = (const char *)sqlite3_value_text(argv[1]);
-  }
-
-  pHash = (fts3Hash *)sqlite3_user_data(context);
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
   p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
 
   if( !p ){
@@ -98854,16 +124096,19 @@ static void testFunc(
   pRet = Tcl_NewObj();
   Tcl_IncrRefCount(pRet);
 
-  if( SQLITE_OK!=p->xCreate(zArg ? 1 : 0, &zArg, &pTokenizer) ){
+  for(i=1; i<argc-1; i++){
+    azArg[i-1] = (const char *)sqlite3_value_text(argv[i]);
+  }
+
+  if( SQLITE_OK!=p->xCreate(argc-2, azArg, &pTokenizer) ){
     zErr = "error in xCreate()";
     goto finish;
   }
   pTokenizer->pModule = p;
-  if( SQLITE_OK!=p->xOpen(pTokenizer, zInput, nInput, &pCsr) ){
+  if( sqlite3Fts3OpenTokenizer(pTokenizer, 0, zInput, nInput, &pCsr) ){
     zErr = "error in xOpen()";
     goto finish;
   }
-  pCsr->pTokenizer = pTokenizer;
 
   while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
     Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
@@ -98932,7 +124177,7 @@ int queryTokenizer(
   sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
   if( SQLITE_ROW==sqlite3_step(pStmt) ){
     if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){
-      memcpy(pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
+      memcpy((void *)pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
     }
   }
 
@@ -98969,6 +124214,9 @@ static void intTestFunc(
   const sqlite3_tokenizer_module *p2;
   sqlite3 *db = (sqlite3 *)sqlite3_user_data(context);
 
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
   /* Test the query function */
   sqlite3Fts3SimpleTokenizerModule(&p1);
   rc = queryTokenizer(db, "simple", &p2);
@@ -99010,16 +124258,16 @@ static void intTestFunc(
 */
 SQLITE_PRIVATE int sqlite3Fts3InitHashTable(
   sqlite3 *db, 
-  fts3Hash *pHash, 
+  Fts3Hash *pHash, 
   const char *zName
 ){
   int rc = SQLITE_OK;
   void *p = (void *)pHash;
   const int any = SQLITE_ANY;
-  char *zTest = 0;
-  char *zTest2 = 0;
 
 #ifdef SQLITE_TEST
+  char *zTest = 0;
+  char *zTest2 = 0;
   void *pdb = (void *)db;
   zTest = sqlite3_mprintf("%s_test", zName);
   zTest2 = sqlite3_mprintf("%s_internal_test", zName);
@@ -99028,18 +124276,26 @@ SQLITE_PRIVATE int sqlite3Fts3InitHashTable(
   }
 #endif
 
-  if( rc!=SQLITE_OK
-   || (rc = sqlite3_create_function(db, zName, 1, any, p, scalarFunc, 0, 0))
-   || (rc = sqlite3_create_function(db, zName, 2, any, p, scalarFunc, 0, 0))
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zName, 1, any, p, scalarFunc, 0, 0);
+  }
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zName, 2, any, p, scalarFunc, 0, 0);
+  }
 #ifdef SQLITE_TEST
-   || (rc = sqlite3_create_function(db, zTest, 2, any, p, testFunc, 0, 0))
-   || (rc = sqlite3_create_function(db, zTest, 3, any, p, testFunc, 0, 0))
-   || (rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0))
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zTest, -1, any, p, testFunc, 0, 0);
+  }
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0);
+  }
 #endif
-  );
 
+#ifdef SQLITE_TEST
   sqlite3_free(zTest);
   sqlite3_free(zTest2);
+#endif
+
   return rc;
 }
 
@@ -99073,7 +124329,10 @@ SQLITE_PRIVATE int sqlite3Fts3InitHashTable(
 */
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 
-
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
 
 
 typedef struct simple_tokenizer {
@@ -99092,12 +124351,12 @@ typedef struct simple_tokenizer_cursor {
 } simple_tokenizer_cursor;
 
 
-/* Forward declaration */
-static const sqlite3_tokenizer_module simpleTokenizerModule;
-
 static int simpleDelim(simple_tokenizer *t, unsigned char c){
   return c<0x80 && t->delim[c];
 }
+static int fts3_isalnum(int x){
+  return (x>='0' && x<='9') || (x>='A' && x<='Z') || (x>='a' && x<='z');
+}
 
 /*
 ** Create a new tokenizer instance.
@@ -99118,7 +124377,7 @@ static int simpleCreate(
   ** information on the initial create.
   */
   if( argc>1 ){
-    int i, n = strlen(argv[1]);
+    int i, n = (int)strlen(argv[1]);
     for(i=0; i<n; i++){
       unsigned char ch = argv[1][i];
       /* We explicitly don't support UTF-8 delimiters for now. */
@@ -99132,7 +124391,7 @@ static int simpleCreate(
     /* Mark non-alphanumeric ASCII characters as delimiters */
     int i;
     for(i=1; i<0x80; i++){
-      t->delim[i] = !isalnum(i);
+      t->delim[i] = !fts3_isalnum(i) ? -1 : 0;
     }
   }
 
@@ -99161,6 +124420,8 @@ static int simpleOpen(
 ){
   simple_tokenizer_cursor *c;
 
+  UNUSED_PARAMETER(pTokenizer);
+
   c = (simple_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
   if( c==NULL ) return SQLITE_NOMEM;
 
@@ -99225,16 +124486,18 @@ static int simpleNext(
     if( c->iOffset>iStartOffset ){
       int i, n = c->iOffset-iStartOffset;
       if( n>c->nTokenAllocated ){
+        char *pNew;
         c->nTokenAllocated = n+20;
-        c->pToken = sqlite3_realloc(c->pToken, c->nTokenAllocated);
-        if( c->pToken==NULL ) return SQLITE_NOMEM;
+        pNew = sqlite3_realloc(c->pToken, c->nTokenAllocated);
+        if( !pNew ) return SQLITE_NOMEM;
+        c->pToken = pNew;
       }
       for(i=0; i<n; i++){
         /* TODO(shess) This needs expansion to handle UTF-8
         ** case-insensitivity.
         */
         unsigned char ch = p[iStartOffset+i];
-        c->pToken[i] = ch<0x80 ? tolower(ch) : ch;
+        c->pToken[i] = (char)((ch>='A' && ch<='Z') ? ch-'A'+'a' : ch);
       }
       *ppToken = c->pToken;
       *pnBytes = n;
@@ -99258,6 +124521,7 @@ static const sqlite3_tokenizer_module simpleTokenizerModule = {
   simpleOpen,
   simpleClose,
   simpleNext,
+  0,
 };
 
 /*
@@ -99273,6 +124537,7677 @@ SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(
 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
 
 /************** End of fts3_tokenizer1.c *************************************/
+/************** Begin file fts3_write.c **************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file is part of the SQLite FTS3 extension module. Specifically,
+** this file contains code to insert, update and delete rows from FTS3
+** tables. It also contains code to merge FTS3 b-tree segments. Some
+** of the sub-routines used to merge segments are also used by the query 
+** code in fts3.c.
+*/
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+
+
+#define FTS_MAX_APPENDABLE_HEIGHT 16
+
+/*
+** When full-text index nodes are loaded from disk, the buffer that they
+** are loaded into has the following number of bytes of padding at the end 
+** of it. i.e. if a full-text index node is 900 bytes in size, then a buffer
+** of 920 bytes is allocated for it.
+**
+** This means that if we have a pointer into a buffer containing node data,
+** it is always safe to read up to two varints from it without risking an
+** overread, even if the node data is corrupted.
+*/
+#define FTS3_NODE_PADDING (FTS3_VARINT_MAX*2)
+
+/*
+** Under certain circumstances, b-tree nodes (doclists) can be loaded into
+** memory incrementally instead of all at once. This can be a big performance
+** win (reduced IO and CPU) if SQLite stops calling the virtual table xNext()
+** method before retrieving all query results (as may happen, for example,
+** if a query has a LIMIT clause).
+**
+** Incremental loading is used for b-tree nodes FTS3_NODE_CHUNK_THRESHOLD 
+** bytes and larger. Nodes are loaded in chunks of FTS3_NODE_CHUNKSIZE bytes.
+** The code is written so that the hard lower-limit for each of these values 
+** is 1. Clearly such small values would be inefficient, but can be useful 
+** for testing purposes.
+**
+** If this module is built with SQLITE_TEST defined, these constants may
+** be overridden at runtime for testing purposes. File fts3_test.c contains
+** a Tcl interface to read and write the values.
+*/
+#ifdef SQLITE_TEST
+int test_fts3_node_chunksize = (4*1024);
+int test_fts3_node_chunk_threshold = (4*1024)*4;
+# define FTS3_NODE_CHUNKSIZE       test_fts3_node_chunksize
+# define FTS3_NODE_CHUNK_THRESHOLD test_fts3_node_chunk_threshold
+#else
+# define FTS3_NODE_CHUNKSIZE (4*1024) 
+# define FTS3_NODE_CHUNK_THRESHOLD (FTS3_NODE_CHUNKSIZE*4)
+#endif
+
+/*
+** The two values that may be meaningfully bound to the :1 parameter in
+** statements SQL_REPLACE_STAT and SQL_SELECT_STAT.
+*/
+#define FTS_STAT_DOCTOTAL      0
+#define FTS_STAT_INCRMERGEHINT 1
+#define FTS_STAT_AUTOINCRMERGE 2
+
+/*
+** If FTS_LOG_MERGES is defined, call sqlite3_log() to report each automatic
+** and incremental merge operation that takes place. This is used for 
+** debugging FTS only, it should not usually be turned on in production
+** systems.
+*/
+#ifdef FTS3_LOG_MERGES
+static void fts3LogMerge(int nMerge, sqlite3_int64 iAbsLevel){
+  sqlite3_log(SQLITE_OK, "%d-way merge from level %d", nMerge, (int)iAbsLevel);
+}
+#else
+#define fts3LogMerge(x, y)
+#endif
+
+
+typedef struct PendingList PendingList;
+typedef struct SegmentNode SegmentNode;
+typedef struct SegmentWriter SegmentWriter;
+
+/*
+** An instance of the following data structure is used to build doclists
+** incrementally. See function fts3PendingListAppend() for details.
+*/
+struct PendingList {
+  int nData;
+  char *aData;
+  int nSpace;
+  sqlite3_int64 iLastDocid;
+  sqlite3_int64 iLastCol;
+  sqlite3_int64 iLastPos;
+};
+
+
+/*
+** Each cursor has a (possibly empty) linked list of the following objects.
+*/
+struct Fts3DeferredToken {
+  Fts3PhraseToken *pToken;        /* Pointer to corresponding expr token */
+  int iCol;                       /* Column token must occur in */
+  Fts3DeferredToken *pNext;       /* Next in list of deferred tokens */
+  PendingList *pList;             /* Doclist is assembled here */
+};
+
+/*
+** An instance of this structure is used to iterate through the terms on
+** a contiguous set of segment b-tree leaf nodes. Although the details of
+** this structure are only manipulated by code in this file, opaque handles
+** of type Fts3SegReader* are also used by code in fts3.c to iterate through
+** terms when querying the full-text index. See functions:
+**
+**   sqlite3Fts3SegReaderNew()
+**   sqlite3Fts3SegReaderFree()
+**   sqlite3Fts3SegReaderIterate()
+**
+** Methods used to manipulate Fts3SegReader structures:
+**
+**   fts3SegReaderNext()
+**   fts3SegReaderFirstDocid()
+**   fts3SegReaderNextDocid()
+*/
+struct Fts3SegReader {
+  int iIdx;                       /* Index within level, or 0x7FFFFFFF for PT */
+  u8 bLookup;                     /* True for a lookup only */
+  u8 rootOnly;                    /* True for a root-only reader */
+
+  sqlite3_int64 iStartBlock;      /* Rowid of first leaf block to traverse */
+  sqlite3_int64 iLeafEndBlock;    /* Rowid of final leaf block to traverse */
+  sqlite3_int64 iEndBlock;        /* Rowid of final block in segment (or 0) */
+  sqlite3_int64 iCurrentBlock;    /* Current leaf block (or 0) */
+
+  char *aNode;                    /* Pointer to node data (or NULL) */
+  int nNode;                      /* Size of buffer at aNode (or 0) */
+  int nPopulate;                  /* If >0, bytes of buffer aNode[] loaded */
+  sqlite3_blob *pBlob;            /* If not NULL, blob handle to read node */
+
+  Fts3HashElem **ppNextElem;
+
+  /* Variables set by fts3SegReaderNext(). These may be read directly
+  ** by the caller. They are valid from the time SegmentReaderNew() returns
+  ** until SegmentReaderNext() returns something other than SQLITE_OK
+  ** (i.e. SQLITE_DONE).
+  */
+  int nTerm;                      /* Number of bytes in current term */
+  char *zTerm;                    /* Pointer to current term */
+  int nTermAlloc;                 /* Allocated size of zTerm buffer */
+  char *aDoclist;                 /* Pointer to doclist of current entry */
+  int nDoclist;                   /* Size of doclist in current entry */
+
+  /* The following variables are used by fts3SegReaderNextDocid() to iterate 
+  ** through the current doclist (aDoclist/nDoclist).
+  */
+  char *pOffsetList;
+  int nOffsetList;                /* For descending pending seg-readers only */
+  sqlite3_int64 iDocid;
+};
+
+#define fts3SegReaderIsPending(p) ((p)->ppNextElem!=0)
+#define fts3SegReaderIsRootOnly(p) ((p)->rootOnly!=0)
+
+/*
+** An instance of this structure is used to create a segment b-tree in the
+** database. The internal details of this type are only accessed by the
+** following functions:
+**
+**   fts3SegWriterAdd()
+**   fts3SegWriterFlush()
+**   fts3SegWriterFree()
+*/
+struct SegmentWriter {
+  SegmentNode *pTree;             /* Pointer to interior tree structure */
+  sqlite3_int64 iFirst;           /* First slot in %_segments written */
+  sqlite3_int64 iFree;            /* Next free slot in %_segments */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nSize;                      /* Size of allocation at aData */
+  int nData;                      /* Bytes of data in aData */
+  char *aData;                    /* Pointer to block from malloc() */
+};
+
+/*
+** Type SegmentNode is used by the following three functions to create
+** the interior part of the segment b+-tree structures (everything except
+** the leaf nodes). These functions and type are only ever used by code
+** within the fts3SegWriterXXX() family of functions described above.
+**
+**   fts3NodeAddTerm()
+**   fts3NodeWrite()
+**   fts3NodeFree()
+**
+** When a b+tree is written to the database (either as a result of a merge
+** or the pending-terms table being flushed), leaves are written into the 
+** database file as soon as they are completely populated. The interior of
+** the tree is assembled in memory and written out only once all leaves have
+** been populated and stored. This is Ok, as the b+-tree fanout is usually
+** very large, meaning that the interior of the tree consumes relatively 
+** little memory.
+*/
+struct SegmentNode {
+  SegmentNode *pParent;           /* Parent node (or NULL for root node) */
+  SegmentNode *pRight;            /* Pointer to right-sibling */
+  SegmentNode *pLeftmost;         /* Pointer to left-most node of this depth */
+  int nEntry;                     /* Number of terms written to node so far */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nData;                      /* Bytes of valid data so far */
+  char *aData;                    /* Node data */
+};
+
+/*
+** Valid values for the second argument to fts3SqlStmt().
+*/
+#define SQL_DELETE_CONTENT             0
+#define SQL_IS_EMPTY                   1
+#define SQL_DELETE_ALL_CONTENT         2 
+#define SQL_DELETE_ALL_SEGMENTS        3
+#define SQL_DELETE_ALL_SEGDIR          4
+#define SQL_DELETE_ALL_DOCSIZE         5
+#define SQL_DELETE_ALL_STAT            6
+#define SQL_SELECT_CONTENT_BY_ROWID    7
+#define SQL_NEXT_SEGMENT_INDEX         8
+#define SQL_INSERT_SEGMENTS            9
+#define SQL_NEXT_SEGMENTS_ID          10
+#define SQL_INSERT_SEGDIR             11
+#define SQL_SELECT_LEVEL              12
+#define SQL_SELECT_LEVEL_RANGE        13
+#define SQL_SELECT_LEVEL_COUNT        14
+#define SQL_SELECT_SEGDIR_MAX_LEVEL   15
+#define SQL_DELETE_SEGDIR_LEVEL       16
+#define SQL_DELETE_SEGMENTS_RANGE     17
+#define SQL_CONTENT_INSERT            18
+#define SQL_DELETE_DOCSIZE            19
+#define SQL_REPLACE_DOCSIZE           20
+#define SQL_SELECT_DOCSIZE            21
+#define SQL_SELECT_STAT               22
+#define SQL_REPLACE_STAT              23
+
+#define SQL_SELECT_ALL_PREFIX_LEVEL   24
+#define SQL_DELETE_ALL_TERMS_SEGDIR   25
+#define SQL_DELETE_SEGDIR_RANGE       26
+#define SQL_SELECT_ALL_LANGID         27
+#define SQL_FIND_MERGE_LEVEL          28
+#define SQL_MAX_LEAF_NODE_ESTIMATE    29
+#define SQL_DELETE_SEGDIR_ENTRY       30
+#define SQL_SHIFT_SEGDIR_ENTRY        31
+#define SQL_SELECT_SEGDIR             32
+#define SQL_CHOMP_SEGDIR              33
+#define SQL_SEGMENT_IS_APPENDABLE     34
+#define SQL_SELECT_INDEXES            35
+#define SQL_SELECT_MXLEVEL            36
+
+/*
+** This function is used to obtain an SQLite prepared statement handle
+** for the statement identified by the second argument. If successful,
+** *pp is set to the requested statement handle and SQLITE_OK returned.
+** Otherwise, an SQLite error code is returned and *pp is set to 0.
+**
+** If argument apVal is not NULL, then it must point to an array with
+** at least as many entries as the requested statement has bound 
+** parameters. The values are bound to the statements parameters before
+** returning.
+*/
+static int fts3SqlStmt(
+  Fts3Table *p,                   /* Virtual table handle */
+  int eStmt,                      /* One of the SQL_XXX constants above */
+  sqlite3_stmt **pp,              /* OUT: Statement handle */
+  sqlite3_value **apVal           /* Values to bind to statement */
+){
+  const char *azSql[] = {
+/* 0  */  "DELETE FROM %Q.'%q_content' WHERE rowid = ?",
+/* 1  */  "SELECT NOT EXISTS(SELECT docid FROM %Q.'%q_content' WHERE rowid!=?)",
+/* 2  */  "DELETE FROM %Q.'%q_content'",
+/* 3  */  "DELETE FROM %Q.'%q_segments'",
+/* 4  */  "DELETE FROM %Q.'%q_segdir'",
+/* 5  */  "DELETE FROM %Q.'%q_docsize'",
+/* 6  */  "DELETE FROM %Q.'%q_stat'",
+/* 7  */  "SELECT %s WHERE rowid=?",
+/* 8  */  "SELECT (SELECT max(idx) FROM %Q.'%q_segdir' WHERE level = ?) + 1",
+/* 9  */  "REPLACE INTO %Q.'%q_segments'(blockid, block) VALUES(?, ?)",
+/* 10 */  "SELECT coalesce((SELECT max(blockid) FROM %Q.'%q_segments') + 1, 1)",
+/* 11 */  "REPLACE INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",
+
+          /* Return segments in order from oldest to newest.*/ 
+/* 12 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
+/* 13 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?"
+            "ORDER BY level DESC, idx ASC",
+
+/* 14 */  "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
+/* 15 */  "SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
+
+/* 16 */  "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
+/* 17 */  "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
+/* 18 */  "INSERT INTO %Q.'%q_content' VALUES(%s)",
+/* 19 */  "DELETE FROM %Q.'%q_docsize' WHERE docid = ?",
+/* 20 */  "REPLACE INTO %Q.'%q_docsize' VALUES(?,?)",
+/* 21 */  "SELECT size FROM %Q.'%q_docsize' WHERE docid=?",
+/* 22 */  "SELECT value FROM %Q.'%q_stat' WHERE id=?",
+/* 23 */  "REPLACE INTO %Q.'%q_stat' VALUES(?,?)",
+/* 24 */  "",
+/* 25 */  "",
+
+/* 26 */ "DELETE FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
+/* 27 */ "SELECT DISTINCT level / (1024 * ?) FROM %Q.'%q_segdir'",
+
+/* This statement is used to determine which level to read the input from
+** when performing an incremental merge. It returns the absolute level number
+** of the oldest level in the db that contains at least ? segments. Or,
+** if no level in the FTS index contains more than ? segments, the statement
+** returns zero rows.  */
+/* 28 */ "SELECT level FROM %Q.'%q_segdir' GROUP BY level HAVING count(*)>=?"
+         "  ORDER BY (level %% 1024) ASC LIMIT 1",
+
+/* Estimate the upper limit on the number of leaf nodes in a new segment
+** created by merging the oldest :2 segments from absolute level :1. See 
+** function sqlite3Fts3Incrmerge() for details.  */
+/* 29 */ "SELECT 2 * total(1 + leaves_end_block - start_block) "
+         "  FROM %Q.'%q_segdir' WHERE level = ? AND idx < ?",
+
+/* SQL_DELETE_SEGDIR_ENTRY
+**   Delete the %_segdir entry on absolute level :1 with index :2.  */
+/* 30 */ "DELETE FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
+
+/* SQL_SHIFT_SEGDIR_ENTRY
+**   Modify the idx value for the segment with idx=:3 on absolute level :2
+**   to :1.  */
+/* 31 */ "UPDATE %Q.'%q_segdir' SET idx = ? WHERE level=? AND idx=?",
+
+/* SQL_SELECT_SEGDIR
+**   Read a single entry from the %_segdir table. The entry from absolute 
+**   level :1 with index value :2.  */
+/* 32 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
+
+/* SQL_CHOMP_SEGDIR
+**   Update the start_block (:1) and root (:2) fields of the %_segdir
+**   entry located on absolute level :3 with index :4.  */
+/* 33 */  "UPDATE %Q.'%q_segdir' SET start_block = ?, root = ?"
+            "WHERE level = ? AND idx = ?",
+
+/* SQL_SEGMENT_IS_APPENDABLE
+**   Return a single row if the segment with end_block=? is appendable. Or
+**   no rows otherwise.  */
+/* 34 */  "SELECT 1 FROM %Q.'%q_segments' WHERE blockid=? AND block IS NULL",
+
+/* SQL_SELECT_INDEXES
+**   Return the list of valid segment indexes for absolute level ?  */
+/* 35 */  "SELECT idx FROM %Q.'%q_segdir' WHERE level=? ORDER BY 1 ASC",
+
+/* SQL_SELECT_MXLEVEL
+**   Return the largest relative level in the FTS index or indexes.  */
+/* 36 */  "SELECT max( level %% 1024 ) FROM %Q.'%q_segdir'"
+  };
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt;
+
+  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
+  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
+  
+  pStmt = p->aStmt[eStmt];
+  if( !pStmt ){
+    char *zSql;
+    if( eStmt==SQL_CONTENT_INSERT ){
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName, p->zWriteExprlist);
+    }else if( eStmt==SQL_SELECT_CONTENT_BY_ROWID ){
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zReadExprlist);
+    }else{
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName);
+    }
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, NULL);
+      sqlite3_free(zSql);
+      assert( rc==SQLITE_OK || pStmt==0 );
+      p->aStmt[eStmt] = pStmt;
+    }
+  }
+  if( apVal ){
+    int i;
+    int nParam = sqlite3_bind_parameter_count(pStmt);
+    for(i=0; rc==SQLITE_OK && i<nParam; i++){
+      rc = sqlite3_bind_value(pStmt, i+1, apVal[i]);
+    }
+  }
+  *pp = pStmt;
+  return rc;
+}
+
+
+static int fts3SelectDocsize(
+  Fts3Table *pTab,                /* FTS3 table handle */
+  sqlite3_int64 iDocid,           /* Docid to bind for SQL_SELECT_DOCSIZE */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  sqlite3_stmt *pStmt = 0;        /* Statement requested from fts3SqlStmt() */
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(pTab, SQL_SELECT_DOCSIZE, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iDocid);
+    rc = sqlite3_step(pStmt);
+    if( rc!=SQLITE_ROW || sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB ){
+      rc = sqlite3_reset(pStmt);
+      if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
+      pStmt = 0;
+    }else{
+      rc = SQLITE_OK;
+    }
+  }
+
+  *ppStmt = pStmt;
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDoctotal(
+  Fts3Table *pTab,                /* Fts3 table handle */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  sqlite3_stmt *pStmt = 0;
+  int rc;
+  rc = fts3SqlStmt(pTab, SQL_SELECT_STAT, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+    if( sqlite3_step(pStmt)!=SQLITE_ROW
+     || sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB
+    ){
+      rc = sqlite3_reset(pStmt);
+      if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
+      pStmt = 0;
+    }
+  }
+  *ppStmt = pStmt;
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDocsize(
+  Fts3Table *pTab,                /* Fts3 table handle */
+  sqlite3_int64 iDocid,           /* Docid to read size data for */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  return fts3SelectDocsize(pTab, iDocid, ppStmt);
+}
+
+/*
+** Similar to fts3SqlStmt(). Except, after binding the parameters in
+** array apVal[] to the SQL statement identified by eStmt, the statement
+** is executed.
+**
+** Returns SQLITE_OK if the statement is successfully executed, or an
+** SQLite error code otherwise.
+*/
+static void fts3SqlExec(
+  int *pRC,                /* Result code */
+  Fts3Table *p,            /* The FTS3 table */
+  int eStmt,               /* Index of statement to evaluate */
+  sqlite3_value **apVal    /* Parameters to bind */
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+  if( *pRC ) return;
+  rc = fts3SqlStmt(p, eStmt, &pStmt, apVal); 
+  if( rc==SQLITE_OK ){
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+  }
+  *pRC = rc;
+}
+
+
+/*
+** This function ensures that the caller has obtained a shared-cache
+** table-lock on the %_content table. This is required before reading
+** data from the fts3 table. If this lock is not acquired first, then
+** the caller may end up holding read-locks on the %_segments and %_segdir
+** tables, but no read-lock on the %_content table. If this happens 
+** a second connection will be able to write to the fts3 table, but
+** attempting to commit those writes might return SQLITE_LOCKED or
+** SQLITE_LOCKED_SHAREDCACHE (because the commit attempts to obtain 
+** write-locks on the %_segments and %_segdir ** tables). 
+**
+** We try to avoid this because if FTS3 returns any error when committing
+** a transaction, the whole transaction will be rolled back. And this is
+** not what users expect when they get SQLITE_LOCKED_SHAREDCACHE. It can
+** still happen if the user reads data directly from the %_segments or
+** %_segdir tables instead of going through FTS3 though.
+**
+** This reasoning does not apply to a content=xxx table.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ReadLock(Fts3Table *p){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pStmt;            /* Statement used to obtain lock */
+
+  if( p->zContentTbl==0 ){
+    rc = fts3SqlStmt(p, SQL_SELECT_CONTENT_BY_ROWID, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_null(pStmt, 1);
+      sqlite3_step(pStmt);
+      rc = sqlite3_reset(pStmt);
+    }
+  }else{
+    rc = SQLITE_OK;
+  }
+
+  return rc;
+}
+
+/*
+** FTS maintains a separate indexes for each language-id (a 32-bit integer).
+** Within each language id, a separate index is maintained to store the
+** document terms, and each configured prefix size (configured the FTS 
+** "prefix=" option). And each index consists of multiple levels ("relative
+** levels").
+**
+** All three of these values (the language id, the specific index and the
+** level within the index) are encoded in 64-bit integer values stored
+** in the %_segdir table on disk. This function is used to convert three
+** separate component values into the single 64-bit integer value that
+** can be used to query the %_segdir table.
+**
+** Specifically, each language-id/index combination is allocated 1024 
+** 64-bit integer level values ("absolute levels"). The main terms index
+** for language-id 0 is allocate values 0-1023. The first prefix index
+** (if any) for language-id 0 is allocated values 1024-2047. And so on.
+** Language 1 indexes are allocated immediately following language 0.
+**
+** So, for a system with nPrefix prefix indexes configured, the block of
+** absolute levels that corresponds to language-id iLangid and index 
+** iIndex starts at absolute level ((iLangid * (nPrefix+1) + iIndex) * 1024).
+*/
+static sqlite3_int64 getAbsoluteLevel(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index in p->aIndex[] */
+  int iLevel                      /* Level of segments */
+){
+  sqlite3_int64 iBase;            /* First absolute level for iLangid/iIndex */
+  assert( iLangid>=0 );
+  assert( p->nIndex>0 );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  iBase = ((sqlite3_int64)iLangid * p->nIndex + iIndex) * FTS3_SEGDIR_MAXLEVEL;
+  return iBase + iLevel;
+}
+
+/*
+** Set *ppStmt to a statement handle that may be used to iterate through
+** all rows in the %_segdir table, from oldest to newest. If successful,
+** return SQLITE_OK. If an error occurs while preparing the statement, 
+** return an SQLite error code.
+**
+** There is only ever one instance of this SQL statement compiled for
+** each FTS3 table.
+**
+** The statement returns the following columns from the %_segdir table:
+**
+**   0: idx
+**   1: start_block
+**   2: leaves_end_block
+**   3: end_block
+**   4: root
+*/
+SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(
+  Fts3Table *p,                   /* FTS3 table */
+  int iLangid,                    /* Language being queried */
+  int iIndex,                     /* Index for p->aIndex[] */
+  int iLevel,                     /* Level to select (relative level) */
+  sqlite3_stmt **ppStmt           /* OUT: Compiled statement */
+){
+  int rc;
+  sqlite3_stmt *pStmt = 0;
+
+  assert( iLevel==FTS3_SEGCURSOR_ALL || iLevel>=0 );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  if( iLevel<0 ){
+    /* "SELECT * FROM %_segdir WHERE level BETWEEN ? AND ? ORDER BY ..." */
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE, &pStmt, 0);
+    if( rc==SQLITE_OK ){ 
+      sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+      sqlite3_bind_int64(pStmt, 2, 
+          getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+      );
+    }
+  }else{
+    /* "SELECT * FROM %_segdir WHERE level = ? ORDER BY ..." */
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
+    if( rc==SQLITE_OK ){ 
+      sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex,iLevel));
+    }
+  }
+  *ppStmt = pStmt;
+  return rc;
+}
+
+
+/*
+** Append a single varint to a PendingList buffer. SQLITE_OK is returned
+** if successful, or an SQLite error code otherwise.
+**
+** This function also serves to allocate the PendingList structure itself.
+** For example, to create a new PendingList structure containing two
+** varints:
+**
+**   PendingList *p = 0;
+**   fts3PendingListAppendVarint(&p, 1);
+**   fts3PendingListAppendVarint(&p, 2);
+*/
+static int fts3PendingListAppendVarint(
+  PendingList **pp,               /* IN/OUT: Pointer to PendingList struct */
+  sqlite3_int64 i                 /* Value to append to data */
+){
+  PendingList *p = *pp;
+
+  /* Allocate or grow the PendingList as required. */
+  if( !p ){
+    p = sqlite3_malloc(sizeof(*p) + 100);
+    if( !p ){
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = 100;
+    p->aData = (char *)&p[1];
+    p->nData = 0;
+  }
+  else if( p->nData+FTS3_VARINT_MAX+1>p->nSpace ){
+    int nNew = p->nSpace * 2;
+    p = sqlite3_realloc(p, sizeof(*p) + nNew);
+    if( !p ){
+      sqlite3_free(*pp);
+      *pp = 0;
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = nNew;
+    p->aData = (char *)&p[1];
+  }
+
+  /* Append the new serialized varint to the end of the list. */
+  p->nData += sqlite3Fts3PutVarint(&p->aData[p->nData], i);
+  p->aData[p->nData] = '\0';
+  *pp = p;
+  return SQLITE_OK;
+}
+
+/*
+** Add a docid/column/position entry to a PendingList structure. Non-zero
+** is returned if the structure is sqlite3_realloced as part of adding
+** the entry. Otherwise, zero.
+**
+** If an OOM error occurs, *pRc is set to SQLITE_NOMEM before returning.
+** Zero is always returned in this case. Otherwise, if no OOM error occurs,
+** it is set to SQLITE_OK.
+*/
+static int fts3PendingListAppend(
+  PendingList **pp,               /* IN/OUT: PendingList structure */
+  sqlite3_int64 iDocid,           /* Docid for entry to add */
+  sqlite3_int64 iCol,             /* Column for entry to add */
+  sqlite3_int64 iPos,             /* Position of term for entry to add */
+  int *pRc                        /* OUT: Return code */
+){
+  PendingList *p = *pp;
+  int rc = SQLITE_OK;
+
+  assert( !p || p->iLastDocid<=iDocid );
+
+  if( !p || p->iLastDocid!=iDocid ){
+    sqlite3_int64 iDelta = iDocid - (p ? p->iLastDocid : 0);
+    if( p ){
+      assert( p->nData<p->nSpace );
+      assert( p->aData[p->nData]==0 );
+      p->nData++;
+    }
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iDelta)) ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = -1;
+    p->iLastPos = 0;
+    p->iLastDocid = iDocid;
+  }
+  if( iCol>0 && p->iLastCol!=iCol ){
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, 1))
+     || SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iCol))
+    ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = iCol;
+    p->iLastPos = 0;
+  }
+  if( iCol>=0 ){
+    assert( iPos>p->iLastPos || (iPos==0 && p->iLastPos==0) );
+    rc = fts3PendingListAppendVarint(&p, 2+iPos-p->iLastPos);
+    if( rc==SQLITE_OK ){
+      p->iLastPos = iPos;
+    }
+  }
+
+ pendinglistappend_out:
+  *pRc = rc;
+  if( p!=*pp ){
+    *pp = p;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Free a PendingList object allocated by fts3PendingListAppend().
+*/
+static void fts3PendingListDelete(PendingList *pList){
+  sqlite3_free(pList);
+}
+
+/*
+** Add an entry to one of the pending-terms hash tables.
+*/
+static int fts3PendingTermsAddOne(
+  Fts3Table *p,
+  int iCol,
+  int iPos,
+  Fts3Hash *pHash,                /* Pending terms hash table to add entry to */
+  const char *zToken,
+  int nToken
+){
+  PendingList *pList;
+  int rc = SQLITE_OK;
+
+  pList = (PendingList *)fts3HashFind(pHash, zToken, nToken);
+  if( pList ){
+    p->nPendingData -= (pList->nData + nToken + sizeof(Fts3HashElem));
+  }
+  if( fts3PendingListAppend(&pList, p->iPrevDocid, iCol, iPos, &rc) ){
+    if( pList==fts3HashInsert(pHash, zToken, nToken, pList) ){
+      /* Malloc failed while inserting the new entry. This can only 
+      ** happen if there was no previous entry for this token.
+      */
+      assert( 0==fts3HashFind(pHash, zToken, nToken) );
+      sqlite3_free(pList);
+      rc = SQLITE_NOMEM;
+    }
+  }
+  if( rc==SQLITE_OK ){
+    p->nPendingData += (pList->nData + nToken + sizeof(Fts3HashElem));
+  }
+  return rc;
+}
+
+/*
+** Tokenize the nul-terminated string zText and add all tokens to the
+** pending-terms hash-table. The docid used is that currently stored in
+** p->iPrevDocid, and the column is specified by argument iCol.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3PendingTermsAdd(
+  Fts3Table *p,                   /* Table into which text will be inserted */
+  int iLangid,                    /* Language id to use */
+  const char *zText,              /* Text of document to be inserted */
+  int iCol,                       /* Column into which text is being inserted */
+  u32 *pnWord                     /* OUT: Number of tokens inserted */
+){
+  int rc;
+  int iStart;
+  int iEnd;
+  int iPos;
+  int nWord = 0;
+
+  char const *zToken;
+  int nToken;
+
+  sqlite3_tokenizer *pTokenizer = p->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCsr;
+  int (*xNext)(sqlite3_tokenizer_cursor *pCursor,
+      const char**,int*,int*,int*,int*);
+
+  assert( pTokenizer && pModule );
+
+  /* If the user has inserted a NULL value, this function may be called with
+  ** zText==0. In this case, add zero token entries to the hash table and 
+  ** return early. */
+  if( zText==0 ){
+    *pnWord = 0;
+    return SQLITE_OK;
+  }
+
+  rc = sqlite3Fts3OpenTokenizer(pTokenizer, iLangid, zText, -1, &pCsr);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  xNext = pModule->xNext;
+  while( SQLITE_OK==rc
+      && SQLITE_OK==(rc = xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos))
+  ){
+    int i;
+    if( iPos>=nWord ) nWord = iPos+1;
+
+    /* Positions cannot be negative; we use -1 as a terminator internally.
+    ** Tokens must have a non-zero length.
+    */
+    if( iPos<0 || !zToken || nToken<=0 ){
+      rc = SQLITE_ERROR;
+      break;
+    }
+
+    /* Add the term to the terms index */
+    rc = fts3PendingTermsAddOne(
+        p, iCol, iPos, &p->aIndex[0].hPending, zToken, nToken
+    );
+    
+    /* Add the term to each of the prefix indexes that it is not too 
+    ** short for. */
+    for(i=1; rc==SQLITE_OK && i<p->nIndex; i++){
+      struct Fts3Index *pIndex = &p->aIndex[i];
+      if( nToken<pIndex->nPrefix ) continue;
+      rc = fts3PendingTermsAddOne(
+          p, iCol, iPos, &pIndex->hPending, zToken, pIndex->nPrefix
+      );
+    }
+  }
+
+  pModule->xClose(pCsr);
+  *pnWord = nWord;
+  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
+}
+
+/* 
+** Calling this function indicates that subsequent calls to 
+** fts3PendingTermsAdd() are to add term/position-list pairs for the
+** contents of the document with docid iDocid.
+*/
+static int fts3PendingTermsDocid(
+  Fts3Table *p,                   /* Full-text table handle */
+  int iLangid,                    /* Language id of row being written */
+  sqlite_int64 iDocid             /* Docid of row being written */
+){
+  assert( iLangid>=0 );
+
+  /* TODO(shess) Explore whether partially flushing the buffer on
+  ** forced-flush would provide better performance.  I suspect that if
+  ** we ordered the doclists by size and flushed the largest until the
+  ** buffer was half empty, that would let the less frequent terms
+  ** generate longer doclists.
+  */
+  if( iDocid<=p->iPrevDocid 
+   || p->iPrevLangid!=iLangid
+   || p->nPendingData>p->nMaxPendingData 
+  ){
+    int rc = sqlite3Fts3PendingTermsFlush(p);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  p->iPrevDocid = iDocid;
+  p->iPrevLangid = iLangid;
+  return SQLITE_OK;
+}
+
+/*
+** Discard the contents of the pending-terms hash tables. 
+*/
+SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *p){
+  int i;
+  for(i=0; i<p->nIndex; i++){
+    Fts3HashElem *pElem;
+    Fts3Hash *pHash = &p->aIndex[i].hPending;
+    for(pElem=fts3HashFirst(pHash); pElem; pElem=fts3HashNext(pElem)){
+      PendingList *pList = (PendingList *)fts3HashData(pElem);
+      fts3PendingListDelete(pList);
+    }
+    fts3HashClear(pHash);
+  }
+  p->nPendingData = 0;
+}
+
+/*
+** This function is called by the xUpdate() method as part of an INSERT
+** operation. It adds entries for each term in the new record to the
+** pendingTerms hash table.
+**
+** Argument apVal is the same as the similarly named argument passed to
+** fts3InsertData(). Parameter iDocid is the docid of the new row.
+*/
+static int fts3InsertTerms(
+  Fts3Table *p, 
+  int iLangid, 
+  sqlite3_value **apVal, 
+  u32 *aSz
+){
+  int i;                          /* Iterator variable */
+  for(i=2; i<p->nColumn+2; i++){
+    const char *zText = (const char *)sqlite3_value_text(apVal[i]);
+    int rc = fts3PendingTermsAdd(p, iLangid, zText, i-2, &aSz[i-2]);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    aSz[p->nColumn] += sqlite3_value_bytes(apVal[i]);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is called by the xUpdate() method for an INSERT operation.
+** The apVal parameter is passed a copy of the apVal argument passed by
+** SQLite to the xUpdate() method. i.e:
+**
+**   apVal[0]                Not used for INSERT.
+**   apVal[1]                rowid
+**   apVal[2]                Left-most user-defined column
+**   ...
+**   apVal[p->nColumn+1]     Right-most user-defined column
+**   apVal[p->nColumn+2]     Hidden column with same name as table
+**   apVal[p->nColumn+3]     Hidden "docid" column (alias for rowid)
+**   apVal[p->nColumn+4]     Hidden languageid column
+*/
+static int fts3InsertData(
+  Fts3Table *p,                   /* Full-text table */
+  sqlite3_value **apVal,          /* Array of values to insert */
+  sqlite3_int64 *piDocid          /* OUT: Docid for row just inserted */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pContentInsert;   /* INSERT INTO %_content VALUES(...) */
+
+  if( p->zContentTbl ){
+    sqlite3_value *pRowid = apVal[p->nColumn+3];
+    if( sqlite3_value_type(pRowid)==SQLITE_NULL ){
+      pRowid = apVal[1];
+    }
+    if( sqlite3_value_type(pRowid)!=SQLITE_INTEGER ){
+      return SQLITE_CONSTRAINT;
+    }
+    *piDocid = sqlite3_value_int64(pRowid);
+    return SQLITE_OK;
+  }
+
+  /* Locate the statement handle used to insert data into the %_content
+  ** table. The SQL for this statement is:
+  **
+  **   INSERT INTO %_content VALUES(?, ?, ?, ...)
+  **
+  ** The statement features N '?' variables, where N is the number of user
+  ** defined columns in the FTS3 table, plus one for the docid field.
+  */
+  rc = fts3SqlStmt(p, SQL_CONTENT_INSERT, &pContentInsert, &apVal[1]);
+  if( rc==SQLITE_OK && p->zLanguageid ){
+    rc = sqlite3_bind_int(
+        pContentInsert, p->nColumn+2, 
+        sqlite3_value_int(apVal[p->nColumn+4])
+    );
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* There is a quirk here. The users INSERT statement may have specified
+  ** a value for the "rowid" field, for the "docid" field, or for both.
+  ** Which is a problem, since "rowid" and "docid" are aliases for the
+  ** same value. For example:
+  **
+  **   INSERT INTO fts3tbl(rowid, docid) VALUES(1, 2);
+  **
+  ** In FTS3, this is an error. It is an error to specify non-NULL values
+  ** for both docid and some other rowid alias.
+  */
+  if( SQLITE_NULL!=sqlite3_value_type(apVal[3+p->nColumn]) ){
+    if( SQLITE_NULL==sqlite3_value_type(apVal[0])
+     && SQLITE_NULL!=sqlite3_value_type(apVal[1])
+    ){
+      /* A rowid/docid conflict. */
+      return SQLITE_ERROR;
+    }
+    rc = sqlite3_bind_value(pContentInsert, 1, apVal[3+p->nColumn]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  /* Execute the statement to insert the record. Set *piDocid to the 
+  ** new docid value. 
+  */
+  sqlite3_step(pContentInsert);
+  rc = sqlite3_reset(pContentInsert);
+
+  *piDocid = sqlite3_last_insert_rowid(p->db);
+  return rc;
+}
+
+
+
+/*
+** Remove all data from the FTS3 table. Clear the hash table containing
+** pending terms.
+*/
+static int fts3DeleteAll(Fts3Table *p, int bContent){
+  int rc = SQLITE_OK;             /* Return code */
+
+  /* Discard the contents of the pending-terms hash table. */
+  sqlite3Fts3PendingTermsClear(p);
+
+  /* Delete everything from the shadow tables. Except, leave %_content as
+  ** is if bContent is false.  */
+  assert( p->zContentTbl==0 || bContent==0 );
+  if( bContent ) fts3SqlExec(&rc, p, SQL_DELETE_ALL_CONTENT, 0);
+  fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGMENTS, 0);
+  fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGDIR, 0);
+  if( p->bHasDocsize ){
+    fts3SqlExec(&rc, p, SQL_DELETE_ALL_DOCSIZE, 0);
+  }
+  if( p->bHasStat ){
+    fts3SqlExec(&rc, p, SQL_DELETE_ALL_STAT, 0);
+  }
+  return rc;
+}
+
+/*
+**
+*/
+static int langidFromSelect(Fts3Table *p, sqlite3_stmt *pSelect){
+  int iLangid = 0;
+  if( p->zLanguageid ) iLangid = sqlite3_column_int(pSelect, p->nColumn+1);
+  return iLangid;
+}
+
+/*
+** The first element in the apVal[] array is assumed to contain the docid
+** (an integer) of a row about to be deleted. Remove all terms from the
+** full-text index.
+*/
+static void fts3DeleteTerms( 
+  int *pRC,               /* Result code */
+  Fts3Table *p,           /* The FTS table to delete from */
+  sqlite3_value *pRowid,  /* The docid to be deleted */
+  u32 *aSz                /* Sizes of deleted document written here */
+){
+  int rc;
+  sqlite3_stmt *pSelect;
+
+  if( *pRC ) return;
+  rc = fts3SqlStmt(p, SQL_SELECT_CONTENT_BY_ROWID, &pSelect, &pRowid);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pSelect) ){
+      int i;
+      int iLangid = langidFromSelect(p, pSelect);
+      rc = fts3PendingTermsDocid(p, iLangid, sqlite3_column_int64(pSelect, 0));
+      for(i=1; rc==SQLITE_OK && i<=p->nColumn; i++){
+        const char *zText = (const char *)sqlite3_column_text(pSelect, i);
+        rc = fts3PendingTermsAdd(p, iLangid, zText, -1, &aSz[i-1]);
+        aSz[p->nColumn] += sqlite3_column_bytes(pSelect, i);
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_reset(pSelect);
+        *pRC = rc;
+        return;
+      }
+    }
+    rc = sqlite3_reset(pSelect);
+  }else{
+    sqlite3_reset(pSelect);
+  }
+  *pRC = rc;
+}
+
+/*
+** Forward declaration to account for the circular dependency between
+** functions fts3SegmentMerge() and fts3AllocateSegdirIdx().
+*/
+static int fts3SegmentMerge(Fts3Table *, int, int, int);
+
+/* 
+** This function allocates a new level iLevel index in the segdir table.
+** Usually, indexes are allocated within a level sequentially starting
+** with 0, so the allocated index is one greater than the value returned
+** by:
+**
+**   SELECT max(idx) FROM %_segdir WHERE level = :iLevel
+**
+** However, if there are already FTS3_MERGE_COUNT indexes at the requested
+** level, they are merged into a single level (iLevel+1) segment and the 
+** allocated index is 0.
+**
+** If successful, *piIdx is set to the allocated index slot and SQLITE_OK
+** returned. Otherwise, an SQLite error code is returned.
+*/
+static int fts3AllocateSegdirIdx(
+  Fts3Table *p, 
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index for p->aIndex */
+  int iLevel, 
+  int *piIdx
+){
+  int rc;                         /* Return Code */
+  sqlite3_stmt *pNextIdx;         /* Query for next idx at level iLevel */
+  int iNext = 0;                  /* Result of query pNextIdx */
+
+  assert( iLangid>=0 );
+  assert( p->nIndex>=1 );
+
+  /* Set variable iNext to the next available segdir index at level iLevel. */
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pNextIdx, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(
+        pNextIdx, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
+    );
+    if( SQLITE_ROW==sqlite3_step(pNextIdx) ){
+      iNext = sqlite3_column_int(pNextIdx, 0);
+    }
+    rc = sqlite3_reset(pNextIdx);
+  }
+
+  if( rc==SQLITE_OK ){
+    /* If iNext is FTS3_MERGE_COUNT, indicating that level iLevel is already
+    ** full, merge all segments in level iLevel into a single iLevel+1
+    ** segment and allocate (newly freed) index 0 at level iLevel. Otherwise,
+    ** if iNext is less than FTS3_MERGE_COUNT, allocate index iNext.
+    */
+    if( iNext>=FTS3_MERGE_COUNT ){
+      fts3LogMerge(16, getAbsoluteLevel(p, iLangid, iIndex, iLevel));
+      rc = fts3SegmentMerge(p, iLangid, iIndex, iLevel);
+      *piIdx = 0;
+    }else{
+      *piIdx = iNext;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The %_segments table is declared as follows:
+**
+**   CREATE TABLE %_segments(blockid INTEGER PRIMARY KEY, block BLOB)
+**
+** This function reads data from a single row of the %_segments table. The
+** specific row is identified by the iBlockid parameter. If paBlob is not
+** NULL, then a buffer is allocated using sqlite3_malloc() and populated
+** with the contents of the blob stored in the "block" column of the 
+** identified table row is. Whether or not paBlob is NULL, *pnBlob is set
+** to the size of the blob in bytes before returning.
+**
+** If an error occurs, or the table does not contain the specified row,
+** an SQLite error code is returned. Otherwise, SQLITE_OK is returned. If
+** paBlob is non-NULL, then it is the responsibility of the caller to
+** eventually free the returned buffer.
+**
+** This function may leave an open sqlite3_blob* handle in the
+** Fts3Table.pSegments variable. This handle is reused by subsequent calls
+** to this function. The handle may be closed by calling the
+** sqlite3Fts3SegmentsClose() function. Reusing a blob handle is a handy
+** performance improvement, but the blob handle should always be closed
+** before control is returned to the user (to prevent a lock being held
+** on the database file for longer than necessary). Thus, any virtual table
+** method (xFilter etc.) that may directly or indirectly call this function
+** must call sqlite3Fts3SegmentsClose() before returning.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ReadBlock(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iBlockid,         /* Access the row with blockid=$iBlockid */
+  char **paBlob,                  /* OUT: Blob data in malloc'd buffer */
+  int *pnBlob,                    /* OUT: Size of blob data */
+  int *pnLoad                     /* OUT: Bytes actually loaded */
+){
+  int rc;                         /* Return code */
+
+  /* pnBlob must be non-NULL. paBlob may be NULL or non-NULL. */
+  assert( pnBlob );
+
+  if( p->pSegments ){
+    rc = sqlite3_blob_reopen(p->pSegments, iBlockid);
+  }else{
+    if( 0==p->zSegmentsTbl ){
+      p->zSegmentsTbl = sqlite3_mprintf("%s_segments", p->zName);
+      if( 0==p->zSegmentsTbl ) return SQLITE_NOMEM;
+    }
+    rc = sqlite3_blob_open(
+       p->db, p->zDb, p->zSegmentsTbl, "block", iBlockid, 0, &p->pSegments
+    );
+  }
+
+  if( rc==SQLITE_OK ){
+    int nByte = sqlite3_blob_bytes(p->pSegments);
+    *pnBlob = nByte;
+    if( paBlob ){
+      char *aByte = sqlite3_malloc(nByte + FTS3_NODE_PADDING);
+      if( !aByte ){
+        rc = SQLITE_NOMEM;
+      }else{
+        if( pnLoad && nByte>(FTS3_NODE_CHUNK_THRESHOLD) ){
+          nByte = FTS3_NODE_CHUNKSIZE;
+          *pnLoad = nByte;
+        }
+        rc = sqlite3_blob_read(p->pSegments, aByte, nByte, 0);
+        memset(&aByte[nByte], 0, FTS3_NODE_PADDING);
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(aByte);
+          aByte = 0;
+        }
+      }
+      *paBlob = aByte;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Close the blob handle at p->pSegments, if it is open. See comments above
+** the sqlite3Fts3ReadBlock() function for details.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *p){
+  sqlite3_blob_close(p->pSegments);
+  p->pSegments = 0;
+}
+    
+static int fts3SegReaderIncrRead(Fts3SegReader *pReader){
+  int nRead;                      /* Number of bytes to read */
+  int rc;                         /* Return code */
+
+  nRead = MIN(pReader->nNode - pReader->nPopulate, FTS3_NODE_CHUNKSIZE);
+  rc = sqlite3_blob_read(
+      pReader->pBlob, 
+      &pReader->aNode[pReader->nPopulate],
+      nRead,
+      pReader->nPopulate
+  );
+
+  if( rc==SQLITE_OK ){
+    pReader->nPopulate += nRead;
+    memset(&pReader->aNode[pReader->nPopulate], 0, FTS3_NODE_PADDING);
+    if( pReader->nPopulate==pReader->nNode ){
+      sqlite3_blob_close(pReader->pBlob);
+      pReader->pBlob = 0;
+      pReader->nPopulate = 0;
+    }
+  }
+  return rc;
+}
+
+static int fts3SegReaderRequire(Fts3SegReader *pReader, char *pFrom, int nByte){
+  int rc = SQLITE_OK;
+  assert( !pReader->pBlob 
+       || (pFrom>=pReader->aNode && pFrom<&pReader->aNode[pReader->nNode])
+  );
+  while( pReader->pBlob && rc==SQLITE_OK 
+     &&  (pFrom - pReader->aNode + nByte)>pReader->nPopulate
+  ){
+    rc = fts3SegReaderIncrRead(pReader);
+  }
+  return rc;
+}
+
+/*
+** Set an Fts3SegReader cursor to point at EOF.
+*/
+static void fts3SegReaderSetEof(Fts3SegReader *pSeg){
+  if( !fts3SegReaderIsRootOnly(pSeg) ){
+    sqlite3_free(pSeg->aNode);
+    sqlite3_blob_close(pSeg->pBlob);
+    pSeg->pBlob = 0;
+  }
+  pSeg->aNode = 0;
+}
+
+/*
+** Move the iterator passed as the first argument to the next term in the
+** segment. If successful, SQLITE_OK is returned. If there is no next term,
+** SQLITE_DONE. Otherwise, an SQLite error code.
+*/
+static int fts3SegReaderNext(
+  Fts3Table *p, 
+  Fts3SegReader *pReader,
+  int bIncr
+){
+  int rc;                         /* Return code of various sub-routines */
+  char *pNext;                    /* Cursor variable */
+  int nPrefix;                    /* Number of bytes in term prefix */
+  int nSuffix;                    /* Number of bytes in term suffix */
+
+  if( !pReader->aDoclist ){
+    pNext = pReader->aNode;
+  }else{
+    pNext = &pReader->aDoclist[pReader->nDoclist];
+  }
+
+  if( !pNext || pNext>=&pReader->aNode[pReader->nNode] ){
+
+    if( fts3SegReaderIsPending(pReader) ){
+      Fts3HashElem *pElem = *(pReader->ppNextElem);
+      if( pElem==0 ){
+        pReader->aNode = 0;
+      }else{
+        PendingList *pList = (PendingList *)fts3HashData(pElem);
+        pReader->zTerm = (char *)fts3HashKey(pElem);
+        pReader->nTerm = fts3HashKeysize(pElem);
+        pReader->nNode = pReader->nDoclist = pList->nData + 1;
+        pReader->aNode = pReader->aDoclist = pList->aData;
+        pReader->ppNextElem++;
+        assert( pReader->aNode );
+      }
+      return SQLITE_OK;
+    }
+
+    fts3SegReaderSetEof(pReader);
+
+    /* If iCurrentBlock>=iLeafEndBlock, this is an EOF condition. All leaf 
+    ** blocks have already been traversed.  */
+    assert( pReader->iCurrentBlock<=pReader->iLeafEndBlock );
+    if( pReader->iCurrentBlock>=pReader->iLeafEndBlock ){
+      return SQLITE_OK;
+    }
+
+    rc = sqlite3Fts3ReadBlock(
+        p, ++pReader->iCurrentBlock, &pReader->aNode, &pReader->nNode, 
+        (bIncr ? &pReader->nPopulate : 0)
+    );
+    if( rc!=SQLITE_OK ) return rc;
+    assert( pReader->pBlob==0 );
+    if( bIncr && pReader->nPopulate<pReader->nNode ){
+      pReader->pBlob = p->pSegments;
+      p->pSegments = 0;
+    }
+    pNext = pReader->aNode;
+  }
+
+  assert( !fts3SegReaderIsPending(pReader) );
+
+  rc = fts3SegReaderRequire(pReader, pNext, FTS3_VARINT_MAX*2);
+  if( rc!=SQLITE_OK ) return rc;
+  
+  /* Because of the FTS3_NODE_PADDING bytes of padding, the following is 
+  ** safe (no risk of overread) even if the node data is corrupted. */
+  pNext += sqlite3Fts3GetVarint32(pNext, &nPrefix);
+  pNext += sqlite3Fts3GetVarint32(pNext, &nSuffix);
+  if( nPrefix<0 || nSuffix<=0 
+   || &pNext[nSuffix]>&pReader->aNode[pReader->nNode] 
+  ){
+    return FTS_CORRUPT_VTAB;
+  }
+
+  if( nPrefix+nSuffix>pReader->nTermAlloc ){
+    int nNew = (nPrefix+nSuffix)*2;
+    char *zNew = sqlite3_realloc(pReader->zTerm, nNew);
+    if( !zNew ){
+      return SQLITE_NOMEM;
+    }
+    pReader->zTerm = zNew;
+    pReader->nTermAlloc = nNew;
+  }
+
+  rc = fts3SegReaderRequire(pReader, pNext, nSuffix+FTS3_VARINT_MAX);
+  if( rc!=SQLITE_OK ) return rc;
+
+  memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
+  pReader->nTerm = nPrefix+nSuffix;
+  pNext += nSuffix;
+  pNext += sqlite3Fts3GetVarint32(pNext, &pReader->nDoclist);
+  pReader->aDoclist = pNext;
+  pReader->pOffsetList = 0;
+
+  /* Check that the doclist does not appear to extend past the end of the
+  ** b-tree node. And that the final byte of the doclist is 0x00. If either 
+  ** of these statements is untrue, then the data structure is corrupt.
+  */
+  if( &pReader->aDoclist[pReader->nDoclist]>&pReader->aNode[pReader->nNode] 
+   || (pReader->nPopulate==0 && pReader->aDoclist[pReader->nDoclist-1])
+  ){
+    return FTS_CORRUPT_VTAB;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Set the SegReader to point to the first docid in the doclist associated
+** with the current term.
+*/
+static int fts3SegReaderFirstDocid(Fts3Table *pTab, Fts3SegReader *pReader){
+  int rc = SQLITE_OK;
+  assert( pReader->aDoclist );
+  assert( !pReader->pOffsetList );
+  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
+    u8 bEof = 0;
+    pReader->iDocid = 0;
+    pReader->nOffsetList = 0;
+    sqlite3Fts3DoclistPrev(0,
+        pReader->aDoclist, pReader->nDoclist, &pReader->pOffsetList, 
+        &pReader->iDocid, &pReader->nOffsetList, &bEof
+    );
+  }else{
+    rc = fts3SegReaderRequire(pReader, pReader->aDoclist, FTS3_VARINT_MAX);
+    if( rc==SQLITE_OK ){
+      int n = sqlite3Fts3GetVarint(pReader->aDoclist, &pReader->iDocid);
+      pReader->pOffsetList = &pReader->aDoclist[n];
+    }
+  }
+  return rc;
+}
+
+/*
+** Advance the SegReader to point to the next docid in the doclist
+** associated with the current term.
+** 
+** If arguments ppOffsetList and pnOffsetList are not NULL, then 
+** *ppOffsetList is set to point to the first column-offset list
+** in the doclist entry (i.e. immediately past the docid varint).
+** *pnOffsetList is set to the length of the set of column-offset
+** lists, not including the nul-terminator byte. For example:
+*/
+static int fts3SegReaderNextDocid(
+  Fts3Table *pTab,
+  Fts3SegReader *pReader,         /* Reader to advance to next docid */
+  char **ppOffsetList,            /* OUT: Pointer to current position-list */
+  int *pnOffsetList               /* OUT: Length of *ppOffsetList in bytes */
+){
+  int rc = SQLITE_OK;
+  char *p = pReader->pOffsetList;
+  char c = 0;
+
+  assert( p );
+
+  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
+    /* A pending-terms seg-reader for an FTS4 table that uses order=desc.
+    ** Pending-terms doclists are always built up in ascending order, so
+    ** we have to iterate through them backwards here. */
+    u8 bEof = 0;
+    if( ppOffsetList ){
+      *ppOffsetList = pReader->pOffsetList;
+      *pnOffsetList = pReader->nOffsetList - 1;
+    }
+    sqlite3Fts3DoclistPrev(0,
+        pReader->aDoclist, pReader->nDoclist, &p, &pReader->iDocid,
+        &pReader->nOffsetList, &bEof
+    );
+    if( bEof ){
+      pReader->pOffsetList = 0;
+    }else{
+      pReader->pOffsetList = p;
+    }
+  }else{
+    char *pEnd = &pReader->aDoclist[pReader->nDoclist];
+
+    /* Pointer p currently points at the first byte of an offset list. The
+    ** following block advances it to point one byte past the end of
+    ** the same offset list. */
+    while( 1 ){
+  
+      /* The following line of code (and the "p++" below the while() loop) is
+      ** normally all that is required to move pointer p to the desired 
+      ** position. The exception is if this node is being loaded from disk
+      ** incrementally and pointer "p" now points to the first byte passed
+      ** the populated part of pReader->aNode[].
+      */
+      while( *p | c ) c = *p++ & 0x80;
+      assert( *p==0 );
+  
+      if( pReader->pBlob==0 || p<&pReader->aNode[pReader->nPopulate] ) break;
+      rc = fts3SegReaderIncrRead(pReader);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    p++;
+  
+    /* If required, populate the output variables with a pointer to and the
+    ** size of the previous offset-list.
+    */
+    if( ppOffsetList ){
+      *ppOffsetList = pReader->pOffsetList;
+      *pnOffsetList = (int)(p - pReader->pOffsetList - 1);
+    }
+
+    while( p<pEnd && *p==0 ) p++;
+  
+    /* If there are no more entries in the doclist, set pOffsetList to
+    ** NULL. Otherwise, set Fts3SegReader.iDocid to the next docid and
+    ** Fts3SegReader.pOffsetList to point to the next offset list before
+    ** returning.
+    */
+    if( p>=pEnd ){
+      pReader->pOffsetList = 0;
+    }else{
+      rc = fts3SegReaderRequire(pReader, p, FTS3_VARINT_MAX);
+      if( rc==SQLITE_OK ){
+        sqlite3_int64 iDelta;
+        pReader->pOffsetList = p + sqlite3Fts3GetVarint(p, &iDelta);
+        if( pTab->bDescIdx ){
+          pReader->iDocid -= iDelta;
+        }else{
+          pReader->iDocid += iDelta;
+        }
+      }
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+
+SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(
+  Fts3Cursor *pCsr, 
+  Fts3MultiSegReader *pMsr,
+  int *pnOvfl
+){
+  Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
+  int nOvfl = 0;
+  int ii;
+  int rc = SQLITE_OK;
+  int pgsz = p->nPgsz;
+
+  assert( p->bFts4 );
+  assert( pgsz>0 );
+
+  for(ii=0; rc==SQLITE_OK && ii<pMsr->nSegment; ii++){
+    Fts3SegReader *pReader = pMsr->apSegment[ii];
+    if( !fts3SegReaderIsPending(pReader) 
+     && !fts3SegReaderIsRootOnly(pReader) 
+    ){
+      sqlite3_int64 jj;
+      for(jj=pReader->iStartBlock; jj<=pReader->iLeafEndBlock; jj++){
+        int nBlob;
+        rc = sqlite3Fts3ReadBlock(p, jj, 0, &nBlob, 0);
+        if( rc!=SQLITE_OK ) break;
+        if( (nBlob+35)>pgsz ){
+          nOvfl += (nBlob + 34)/pgsz;
+        }
+      }
+    }
+  }
+  *pnOvfl = nOvfl;
+  return rc;
+}
+
+/*
+** Free all allocations associated with the iterator passed as the 
+** second argument.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFree(Fts3SegReader *pReader){
+  if( pReader && !fts3SegReaderIsPending(pReader) ){
+    sqlite3_free(pReader->zTerm);
+    if( !fts3SegReaderIsRootOnly(pReader) ){
+      sqlite3_free(pReader->aNode);
+      sqlite3_blob_close(pReader->pBlob);
+    }
+  }
+  sqlite3_free(pReader);
+}
+
+/*
+** Allocate a new SegReader object.
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderNew(
+  int iAge,                       /* Segment "age". */
+  int bLookup,                    /* True for a lookup only */
+  sqlite3_int64 iStartLeaf,       /* First leaf to traverse */
+  sqlite3_int64 iEndLeaf,         /* Final leaf to traverse */
+  sqlite3_int64 iEndBlock,        /* Final block of segment */
+  const char *zRoot,              /* Buffer containing root node */
+  int nRoot,                      /* Size of buffer containing root node */
+  Fts3SegReader **ppReader        /* OUT: Allocated Fts3SegReader */
+){
+  Fts3SegReader *pReader;         /* Newly allocated SegReader object */
+  int nExtra = 0;                 /* Bytes to allocate segment root node */
+
+  assert( iStartLeaf<=iEndLeaf );
+  if( iStartLeaf==0 ){
+    nExtra = nRoot + FTS3_NODE_PADDING;
+  }
+
+  pReader = (Fts3SegReader *)sqlite3_malloc(sizeof(Fts3SegReader) + nExtra);
+  if( !pReader ){
+    return SQLITE_NOMEM;
+  }
+  memset(pReader, 0, sizeof(Fts3SegReader));
+  pReader->iIdx = iAge;
+  pReader->bLookup = bLookup!=0;
+  pReader->iStartBlock = iStartLeaf;
+  pReader->iLeafEndBlock = iEndLeaf;
+  pReader->iEndBlock = iEndBlock;
+
+  if( nExtra ){
+    /* The entire segment is stored in the root node. */
+    pReader->aNode = (char *)&pReader[1];
+    pReader->rootOnly = 1;
+    pReader->nNode = nRoot;
+    memcpy(pReader->aNode, zRoot, nRoot);
+    memset(&pReader->aNode[nRoot], 0, FTS3_NODE_PADDING);
+  }else{
+    pReader->iCurrentBlock = iStartLeaf-1;
+  }
+  *ppReader = pReader;
+  return SQLITE_OK;
+}
+
+/*
+** This is a comparison function used as a qsort() callback when sorting
+** an array of pending terms by term. This occurs as part of flushing
+** the contents of the pending-terms hash table to the database.
+*/
+static int fts3CompareElemByTerm(const void *lhs, const void *rhs){
+  char *z1 = fts3HashKey(*(Fts3HashElem **)lhs);
+  char *z2 = fts3HashKey(*(Fts3HashElem **)rhs);
+  int n1 = fts3HashKeysize(*(Fts3HashElem **)lhs);
+  int n2 = fts3HashKeysize(*(Fts3HashElem **)rhs);
+
+  int n = (n1<n2 ? n1 : n2);
+  int c = memcmp(z1, z2, n);
+  if( c==0 ){
+    c = n1 - n2;
+  }
+  return c;
+}
+
+/*
+** This function is used to allocate an Fts3SegReader that iterates through
+** a subset of the terms stored in the Fts3Table.pendingTerms array.
+**
+** If the isPrefixIter parameter is zero, then the returned SegReader iterates
+** through each term in the pending-terms table. Or, if isPrefixIter is
+** non-zero, it iterates through each term and its prefixes. For example, if
+** the pending terms hash table contains the terms "sqlite", "mysql" and
+** "firebird", then the iterator visits the following 'terms' (in the order
+** shown):
+**
+**   f fi fir fire fireb firebi firebir firebird
+**   m my mys mysq mysql
+**   s sq sql sqli sqlit sqlite
+**
+** Whereas if isPrefixIter is zero, the terms visited are:
+**
+**   firebird mysql sqlite
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderPending(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iIndex,                     /* Index for p->aIndex */
+  const char *zTerm,              /* Term to search for */
+  int nTerm,                      /* Size of buffer zTerm */
+  int bPrefix,                    /* True for a prefix iterator */
+  Fts3SegReader **ppReader        /* OUT: SegReader for pending-terms */
+){
+  Fts3SegReader *pReader = 0;     /* Fts3SegReader object to return */
+  Fts3HashElem *pE;               /* Iterator variable */
+  Fts3HashElem **aElem = 0;       /* Array of term hash entries to scan */
+  int nElem = 0;                  /* Size of array at aElem */
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Hash *pHash;
+
+  pHash = &p->aIndex[iIndex].hPending;
+  if( bPrefix ){
+    int nAlloc = 0;               /* Size of allocated array at aElem */
+
+    for(pE=fts3HashFirst(pHash); pE; pE=fts3HashNext(pE)){
+      char *zKey = (char *)fts3HashKey(pE);
+      int nKey = fts3HashKeysize(pE);
+      if( nTerm==0 || (nKey>=nTerm && 0==memcmp(zKey, zTerm, nTerm)) ){
+        if( nElem==nAlloc ){
+          Fts3HashElem **aElem2;
+          nAlloc += 16;
+          aElem2 = (Fts3HashElem **)sqlite3_realloc(
+              aElem, nAlloc*sizeof(Fts3HashElem *)
+          );
+          if( !aElem2 ){
+            rc = SQLITE_NOMEM;
+            nElem = 0;
+            break;
+          }
+          aElem = aElem2;
+        }
+
+        aElem[nElem++] = pE;
+      }
+    }
+
+    /* If more than one term matches the prefix, sort the Fts3HashElem
+    ** objects in term order using qsort(). This uses the same comparison
+    ** callback as is used when flushing terms to disk.
+    */
+    if( nElem>1 ){
+      qsort(aElem, nElem, sizeof(Fts3HashElem *), fts3CompareElemByTerm);
+    }
+
+  }else{
+    /* The query is a simple term lookup that matches at most one term in
+    ** the index. All that is required is a straight hash-lookup. 
+    **
+    ** Because the stack address of pE may be accessed via the aElem pointer
+    ** below, the "Fts3HashElem *pE" must be declared so that it is valid
+    ** within this entire function, not just this "else{...}" block.
+    */
+    pE = fts3HashFindElem(pHash, zTerm, nTerm);
+    if( pE ){
+      aElem = &pE;
+      nElem = 1;
+    }
+  }
+
+  if( nElem>0 ){
+    int nByte = sizeof(Fts3SegReader) + (nElem+1)*sizeof(Fts3HashElem *);
+    pReader = (Fts3SegReader *)sqlite3_malloc(nByte);
+    if( !pReader ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pReader, 0, nByte);
+      pReader->iIdx = 0x7FFFFFFF;
+      pReader->ppNextElem = (Fts3HashElem **)&pReader[1];
+      memcpy(pReader->ppNextElem, aElem, nElem*sizeof(Fts3HashElem *));
+    }
+  }
+
+  if( bPrefix ){
+    sqlite3_free(aElem);
+  }
+  *ppReader = pReader;
+  return rc;
+}
+
+/*
+** Compare the entries pointed to by two Fts3SegReader structures. 
+** Comparison is as follows:
+**
+**   1) EOF is greater than not EOF.
+**
+**   2) The current terms (if any) are compared using memcmp(). If one
+**      term is a prefix of another, the longer term is considered the
+**      larger.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc;
+  if( pLhs->aNode && pRhs->aNode ){
+    int rc2 = pLhs->nTerm - pRhs->nTerm;
+    if( rc2<0 ){
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pLhs->nTerm);
+    }else{
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pRhs->nTerm);
+    }
+    if( rc==0 ){
+      rc = rc2;
+    }
+  }else{
+    rc = (pLhs->aNode==0) - (pRhs->aNode==0);
+  }
+  if( rc==0 ){
+    rc = pRhs->iIdx - pLhs->iIdx;
+  }
+  assert( rc!=0 );
+  return rc;
+}
+
+/*
+** A different comparison function for SegReader structures. In this
+** version, it is assumed that each SegReader points to an entry in
+** a doclist for identical terms. Comparison is made as follows:
+**
+**   1) EOF (end of doclist in this case) is greater than not EOF.
+**
+**   2) By current docid.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderDoclistCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
+  if( rc==0 ){
+    if( pLhs->iDocid==pRhs->iDocid ){
+      rc = pRhs->iIdx - pLhs->iIdx;
+    }else{
+      rc = (pLhs->iDocid > pRhs->iDocid) ? 1 : -1;
+    }
+  }
+  assert( pLhs->aNode && pRhs->aNode );
+  return rc;
+}
+static int fts3SegReaderDoclistCmpRev(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
+  if( rc==0 ){
+    if( pLhs->iDocid==pRhs->iDocid ){
+      rc = pRhs->iIdx - pLhs->iIdx;
+    }else{
+      rc = (pLhs->iDocid < pRhs->iDocid) ? 1 : -1;
+    }
+  }
+  assert( pLhs->aNode && pRhs->aNode );
+  return rc;
+}
+
+/*
+** Compare the term that the Fts3SegReader object passed as the first argument
+** points to with the term specified by arguments zTerm and nTerm. 
+**
+** If the pSeg iterator is already at EOF, return 0. Otherwise, return
+** -ve if the pSeg term is less than zTerm/nTerm, 0 if the two terms are
+** equal, or +ve if the pSeg term is greater than zTerm/nTerm.
+*/
+static int fts3SegReaderTermCmp(
+  Fts3SegReader *pSeg,            /* Segment reader object */
+  const char *zTerm,              /* Term to compare to */
+  int nTerm                       /* Size of term zTerm in bytes */
+){
+  int res = 0;
+  if( pSeg->aNode ){
+    if( pSeg->nTerm>nTerm ){
+      res = memcmp(pSeg->zTerm, zTerm, nTerm);
+    }else{
+      res = memcmp(pSeg->zTerm, zTerm, pSeg->nTerm);
+    }
+    if( res==0 ){
+      res = pSeg->nTerm-nTerm;
+    }
+  }
+  return res;
+}
+
+/*
+** Argument apSegment is an array of nSegment elements. It is known that
+** the final (nSegment-nSuspect) members are already in sorted order
+** (according to the comparison function provided). This function shuffles
+** the array around until all entries are in sorted order.
+*/
+static void fts3SegReaderSort(
+  Fts3SegReader **apSegment,                     /* Array to sort entries of */
+  int nSegment,                                  /* Size of apSegment array */
+  int nSuspect,                                  /* Unsorted entry count */
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *)  /* Comparison function */
+){
+  int i;                          /* Iterator variable */
+
+  assert( nSuspect<=nSegment );
+
+  if( nSuspect==nSegment ) nSuspect--;
+  for(i=nSuspect-1; i>=0; i--){
+    int j;
+    for(j=i; j<(nSegment-1); j++){
+      Fts3SegReader *pTmp;
+      if( xCmp(apSegment[j], apSegment[j+1])<0 ) break;
+      pTmp = apSegment[j+1];
+      apSegment[j+1] = apSegment[j];
+      apSegment[j] = pTmp;
+    }
+  }
+
+#ifndef NDEBUG
+  /* Check that the list really is sorted now. */
+  for(i=0; i<(nSuspect-1); i++){
+    assert( xCmp(apSegment[i], apSegment[i+1])<0 );
+  }
+#endif
+}
+
+/* 
+** Insert a record into the %_segments table.
+*/
+static int fts3WriteSegment(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_int64 iBlock,           /* Block id for new block */
+  char *z,                        /* Pointer to buffer containing block data */
+  int n                           /* Size of buffer z in bytes */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGMENTS, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iBlock);
+    sqlite3_bind_blob(pStmt, 2, z, n, SQLITE_STATIC);
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+  }
+  return rc;
+}
+
+/*
+** Find the largest relative level number in the table. If successful, set
+** *pnMax to this value and return SQLITE_OK. Otherwise, if an error occurs,
+** set *pnMax to zero and return an SQLite error code.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MaxLevel(Fts3Table *p, int *pnMax){
+  int rc;
+  int mxLevel = 0;
+  sqlite3_stmt *pStmt = 0;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_MXLEVEL, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      mxLevel = sqlite3_column_int(pStmt, 0);
+    }
+    rc = sqlite3_reset(pStmt);
+  }
+  *pnMax = mxLevel;
+  return rc;
+}
+
+/* 
+** Insert a record into the %_segdir table.
+*/
+static int fts3WriteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_int64 iLevel,           /* Value for "level" field (absolute level) */
+  int iIdx,                       /* Value for "idx" field */
+  sqlite3_int64 iStartBlock,      /* Value for "start_block" field */
+  sqlite3_int64 iLeafEndBlock,    /* Value for "leaves_end_block" field */
+  sqlite3_int64 iEndBlock,        /* Value for "end_block" field */
+  char *zRoot,                    /* Blob value for "root" field */
+  int nRoot                       /* Number of bytes in buffer zRoot */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGDIR, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iLevel);
+    sqlite3_bind_int(pStmt, 2, iIdx);
+    sqlite3_bind_int64(pStmt, 3, iStartBlock);
+    sqlite3_bind_int64(pStmt, 4, iLeafEndBlock);
+    sqlite3_bind_int64(pStmt, 5, iEndBlock);
+    sqlite3_bind_blob(pStmt, 6, zRoot, nRoot, SQLITE_STATIC);
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+  }
+  return rc;
+}
+
+/*
+** Return the size of the common prefix (if any) shared by zPrev and
+** zNext, in bytes. For example, 
+**
+**   fts3PrefixCompress("abc", 3, "abcdef", 6)   // returns 3
+**   fts3PrefixCompress("abX", 3, "abcdef", 6)   // returns 2
+**   fts3PrefixCompress("abX", 3, "Xbcdef", 6)   // returns 0
+*/
+static int fts3PrefixCompress(
+  const char *zPrev,              /* Buffer containing previous term */
+  int nPrev,                      /* Size of buffer zPrev in bytes */
+  const char *zNext,              /* Buffer containing next term */
+  int nNext                       /* Size of buffer zNext in bytes */
+){
+  int n;
+  UNUSED_PARAMETER(nNext);
+  for(n=0; n<nPrev && zPrev[n]==zNext[n]; n++);
+  return n;
+}
+
+/*
+** Add term zTerm to the SegmentNode. It is guaranteed that zTerm is larger
+** (according to memcmp) than the previous term.
+*/
+static int fts3NodeAddTerm(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentNode **ppTree,           /* IN/OUT: SegmentNode handle */ 
+  int isCopyTerm,                 /* True if zTerm/nTerm is transient */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm                       /* Size of term in bytes */
+){
+  SegmentNode *pTree = *ppTree;
+  int rc;
+  SegmentNode *pNew;
+
+  /* First try to append the term to the current node. Return early if 
+  ** this is possible.
+  */
+  if( pTree ){
+    int nData = pTree->nData;     /* Current size of node in bytes */
+    int nReq = nData;             /* Required space after adding zTerm */
+    int nPrefix;                  /* Number of bytes of prefix compression */
+    int nSuffix;                  /* Suffix length */
+
+    nPrefix = fts3PrefixCompress(pTree->zTerm, pTree->nTerm, zTerm, nTerm);
+    nSuffix = nTerm-nPrefix;
+
+    nReq += sqlite3Fts3VarintLen(nPrefix)+sqlite3Fts3VarintLen(nSuffix)+nSuffix;
+    if( nReq<=p->nNodeSize || !pTree->zTerm ){
+
+      if( nReq>p->nNodeSize ){
+        /* An unusual case: this is the first term to be added to the node
+        ** and the static node buffer (p->nNodeSize bytes) is not large
+        ** enough. Use a separately malloced buffer instead This wastes
+        ** p->nNodeSize bytes, but since this scenario only comes about when
+        ** the database contain two terms that share a prefix of almost 2KB, 
+        ** this is not expected to be a serious problem. 
+        */
+        assert( pTree->aData==(char *)&pTree[1] );
+        pTree->aData = (char *)sqlite3_malloc(nReq);
+        if( !pTree->aData ){
+          return SQLITE_NOMEM;
+        }
+      }
+
+      if( pTree->zTerm ){
+        /* There is no prefix-length field for first term in a node */
+        nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nPrefix);
+      }
+
+      nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nSuffix);
+      memcpy(&pTree->aData[nData], &zTerm[nPrefix], nSuffix);
+      pTree->nData = nData + nSuffix;
+      pTree->nEntry++;
+
+      if( isCopyTerm ){
+        if( pTree->nMalloc<nTerm ){
+          char *zNew = sqlite3_realloc(pTree->zMalloc, nTerm*2);
+          if( !zNew ){
+            return SQLITE_NOMEM;
+          }
+          pTree->nMalloc = nTerm*2;
+          pTree->zMalloc = zNew;
+        }
+        pTree->zTerm = pTree->zMalloc;
+        memcpy(pTree->zTerm, zTerm, nTerm);
+        pTree->nTerm = nTerm;
+      }else{
+        pTree->zTerm = (char *)zTerm;
+        pTree->nTerm = nTerm;
+      }
+      return SQLITE_OK;
+    }
+  }
+
+  /* If control flows to here, it was not possible to append zTerm to the
+  ** current node. Create a new node (a right-sibling of the current node).
+  ** If this is the first node in the tree, the term is added to it.
+  **
+  ** Otherwise, the term is not added to the new node, it is left empty for
+  ** now. Instead, the term is inserted into the parent of pTree. If pTree 
+  ** has no parent, one is created here.
+  */
+  pNew = (SegmentNode *)sqlite3_malloc(sizeof(SegmentNode) + p->nNodeSize);
+  if( !pNew ){
+    return SQLITE_NOMEM;
+  }
+  memset(pNew, 0, sizeof(SegmentNode));
+  pNew->nData = 1 + FTS3_VARINT_MAX;
+  pNew->aData = (char *)&pNew[1];
+
+  if( pTree ){
+    SegmentNode *pParent = pTree->pParent;
+    rc = fts3NodeAddTerm(p, &pParent, isCopyTerm, zTerm, nTerm);
+    if( pTree->pParent==0 ){
+      pTree->pParent = pParent;
+    }
+    pTree->pRight = pNew;
+    pNew->pLeftmost = pTree->pLeftmost;
+    pNew->pParent = pParent;
+    pNew->zMalloc = pTree->zMalloc;
+    pNew->nMalloc = pTree->nMalloc;
+    pTree->zMalloc = 0;
+  }else{
+    pNew->pLeftmost = pNew;
+    rc = fts3NodeAddTerm(p, &pNew, isCopyTerm, zTerm, nTerm); 
+  }
+
+  *ppTree = pNew;
+  return rc;
+}
+
+/*
+** Helper function for fts3NodeWrite().
+*/
+static int fts3TreeFinishNode(
+  SegmentNode *pTree, 
+  int iHeight, 
+  sqlite3_int64 iLeftChild
+){
+  int nStart;
+  assert( iHeight>=1 && iHeight<128 );
+  nStart = FTS3_VARINT_MAX - sqlite3Fts3VarintLen(iLeftChild);
+  pTree->aData[nStart] = (char)iHeight;
+  sqlite3Fts3PutVarint(&pTree->aData[nStart+1], iLeftChild);
+  return nStart;
+}
+
+/*
+** Write the buffer for the segment node pTree and all of its peers to the
+** database. Then call this function recursively to write the parent of 
+** pTree and its peers to the database. 
+**
+** Except, if pTree is a root node, do not write it to the database. Instead,
+** set output variables *paRoot and *pnRoot to contain the root node.
+**
+** If successful, SQLITE_OK is returned and output variable *piLast is
+** set to the largest blockid written to the database (or zero if no
+** blocks were written to the db). Otherwise, an SQLite error code is 
+** returned.
+*/
+static int fts3NodeWrite(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentNode *pTree,             /* SegmentNode handle */
+  int iHeight,                    /* Height of this node in tree */
+  sqlite3_int64 iLeaf,            /* Block id of first leaf node */
+  sqlite3_int64 iFree,            /* Block id of next free slot in %_segments */
+  sqlite3_int64 *piLast,          /* OUT: Block id of last entry written */
+  char **paRoot,                  /* OUT: Data for root node */
+  int *pnRoot                     /* OUT: Size of root node in bytes */
+){
+  int rc = SQLITE_OK;
+
+  if( !pTree->pParent ){
+    /* Root node of the tree. */
+    int nStart = fts3TreeFinishNode(pTree, iHeight, iLeaf);
+    *piLast = iFree-1;
+    *pnRoot = pTree->nData - nStart;
+    *paRoot = &pTree->aData[nStart];
+  }else{
+    SegmentNode *pIter;
+    sqlite3_int64 iNextFree = iFree;
+    sqlite3_int64 iNextLeaf = iLeaf;
+    for(pIter=pTree->pLeftmost; pIter && rc==SQLITE_OK; pIter=pIter->pRight){
+      int nStart = fts3TreeFinishNode(pIter, iHeight, iNextLeaf);
+      int nWrite = pIter->nData - nStart;
+  
+      rc = fts3WriteSegment(p, iNextFree, &pIter->aData[nStart], nWrite);
+      iNextFree++;
+      iNextLeaf += (pIter->nEntry+1);
+    }
+    if( rc==SQLITE_OK ){
+      assert( iNextLeaf==iFree );
+      rc = fts3NodeWrite(
+          p, pTree->pParent, iHeight+1, iFree, iNextFree, piLast, paRoot, pnRoot
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Free all memory allocations associated with the tree pTree.
+*/
+static void fts3NodeFree(SegmentNode *pTree){
+  if( pTree ){
+    SegmentNode *p = pTree->pLeftmost;
+    fts3NodeFree(p->pParent);
+    while( p ){
+      SegmentNode *pRight = p->pRight;
+      if( p->aData!=(char *)&p[1] ){
+        sqlite3_free(p->aData);
+      }
+      assert( pRight==0 || p->zMalloc==0 );
+      sqlite3_free(p->zMalloc);
+      sqlite3_free(p);
+      p = pRight;
+    }
+  }
+}
+
+/*
+** Add a term to the segment being constructed by the SegmentWriter object
+** *ppWriter. When adding the first term to a segment, *ppWriter should
+** be passed NULL. This function will allocate a new SegmentWriter object
+** and return it via the input/output variable *ppWriter in this case.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterAdd(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter **ppWriter,       /* IN/OUT: SegmentWriter handle */ 
+  int isCopyTerm,                 /* True if buffer zTerm must be copied */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm,                      /* Size of term in bytes */
+  const char *aDoclist,           /* Pointer to buffer containing doclist */
+  int nDoclist                    /* Size of doclist in bytes */
+){
+  int nPrefix;                    /* Size of term prefix in bytes */
+  int nSuffix;                    /* Size of term suffix in bytes */
+  int nReq;                       /* Number of bytes required on leaf page */
+  int nData;
+  SegmentWriter *pWriter = *ppWriter;
+
+  if( !pWriter ){
+    int rc;
+    sqlite3_stmt *pStmt;
+
+    /* Allocate the SegmentWriter structure */
+    pWriter = (SegmentWriter *)sqlite3_malloc(sizeof(SegmentWriter));
+    if( !pWriter ) return SQLITE_NOMEM;
+    memset(pWriter, 0, sizeof(SegmentWriter));
+    *ppWriter = pWriter;
+
+    /* Allocate a buffer in which to accumulate data */
+    pWriter->aData = (char *)sqlite3_malloc(p->nNodeSize);
+    if( !pWriter->aData ) return SQLITE_NOMEM;
+    pWriter->nSize = p->nNodeSize;
+
+    /* Find the next free blockid in the %_segments table */
+    rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pStmt, 0);
+    if( rc!=SQLITE_OK ) return rc;
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      pWriter->iFree = sqlite3_column_int64(pStmt, 0);
+      pWriter->iFirst = pWriter->iFree;
+    }
+    rc = sqlite3_reset(pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  nData = pWriter->nData;
+
+  nPrefix = fts3PrefixCompress(pWriter->zTerm, pWriter->nTerm, zTerm, nTerm);
+  nSuffix = nTerm-nPrefix;
+
+  /* Figure out how many bytes are required by this new entry */
+  nReq = sqlite3Fts3VarintLen(nPrefix) +    /* varint containing prefix size */
+    sqlite3Fts3VarintLen(nSuffix) +         /* varint containing suffix size */
+    nSuffix +                               /* Term suffix */
+    sqlite3Fts3VarintLen(nDoclist) +        /* Size of doclist */
+    nDoclist;                               /* Doclist data */
+
+  if( nData>0 && nData+nReq>p->nNodeSize ){
+    int rc;
+
+    /* The current leaf node is full. Write it out to the database. */
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, nData);
+    if( rc!=SQLITE_OK ) return rc;
+    p->nLeafAdd++;
+
+    /* Add the current term to the interior node tree. The term added to
+    ** the interior tree must:
+    **
+    **   a) be greater than the largest term on the leaf node just written
+    **      to the database (still available in pWriter->zTerm), and
+    **
+    **   b) be less than or equal to the term about to be added to the new
+    **      leaf node (zTerm/nTerm).
+    **
+    ** In other words, it must be the prefix of zTerm 1 byte longer than
+    ** the common prefix (if any) of zTerm and pWriter->zTerm.
+    */
+    assert( nPrefix<nTerm );
+    rc = fts3NodeAddTerm(p, &pWriter->pTree, isCopyTerm, zTerm, nPrefix+1);
+    if( rc!=SQLITE_OK ) return rc;
+
+    nData = 0;
+    pWriter->nTerm = 0;
+
+    nPrefix = 0;
+    nSuffix = nTerm;
+    nReq = 1 +                              /* varint containing prefix size */
+      sqlite3Fts3VarintLen(nTerm) +         /* varint containing suffix size */
+      nTerm +                               /* Term suffix */
+      sqlite3Fts3VarintLen(nDoclist) +      /* Size of doclist */
+      nDoclist;                             /* Doclist data */
+  }
+
+  /* If the buffer currently allocated is too small for this entry, realloc
+  ** the buffer to make it large enough.
+  */
+  if( nReq>pWriter->nSize ){
+    char *aNew = sqlite3_realloc(pWriter->aData, nReq);
+    if( !aNew ) return SQLITE_NOMEM;
+    pWriter->aData = aNew;
+    pWriter->nSize = nReq;
+  }
+  assert( nData+nReq<=pWriter->nSize );
+
+  /* Append the prefix-compressed term and doclist to the buffer. */
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nPrefix);
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nSuffix);
+  memcpy(&pWriter->aData[nData], &zTerm[nPrefix], nSuffix);
+  nData += nSuffix;
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nDoclist);
+  memcpy(&pWriter->aData[nData], aDoclist, nDoclist);
+  pWriter->nData = nData + nDoclist;
+
+  /* Save the current term so that it can be used to prefix-compress the next.
+  ** If the isCopyTerm parameter is true, then the buffer pointed to by
+  ** zTerm is transient, so take a copy of the term data. Otherwise, just
+  ** store a copy of the pointer.
+  */
+  if( isCopyTerm ){
+    if( nTerm>pWriter->nMalloc ){
+      char *zNew = sqlite3_realloc(pWriter->zMalloc, nTerm*2);
+      if( !zNew ){
+        return SQLITE_NOMEM;
+      }
+      pWriter->nMalloc = nTerm*2;
+      pWriter->zMalloc = zNew;
+      pWriter->zTerm = zNew;
+    }
+    assert( pWriter->zTerm==pWriter->zMalloc );
+    memcpy(pWriter->zTerm, zTerm, nTerm);
+  }else{
+    pWriter->zTerm = (char *)zTerm;
+  }
+  pWriter->nTerm = nTerm;
+
+  return SQLITE_OK;
+}
+
+/*
+** Flush all data associated with the SegmentWriter object pWriter to the
+** database. This function must be called after all terms have been added
+** to the segment using fts3SegWriterAdd(). If successful, SQLITE_OK is
+** returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterFlush(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter *pWriter,         /* SegmentWriter to flush to the db */
+  sqlite3_int64 iLevel,           /* Value for 'level' column of %_segdir */
+  int iIdx                        /* Value for 'idx' column of %_segdir */
+){
+  int rc;                         /* Return code */
+  if( pWriter->pTree ){
+    sqlite3_int64 iLast = 0;      /* Largest block id written to database */
+    sqlite3_int64 iLastLeaf;      /* Largest leaf block id written to db */
+    char *zRoot = NULL;           /* Pointer to buffer containing root node */
+    int nRoot = 0;                /* Size of buffer zRoot */
+
+    iLastLeaf = pWriter->iFree;
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, pWriter->nData);
+    if( rc==SQLITE_OK ){
+      rc = fts3NodeWrite(p, pWriter->pTree, 1,
+          pWriter->iFirst, pWriter->iFree, &iLast, &zRoot, &nRoot);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3WriteSegdir(
+          p, iLevel, iIdx, pWriter->iFirst, iLastLeaf, iLast, zRoot, nRoot);
+    }
+  }else{
+    /* The entire tree fits on the root node. Write it to the segdir table. */
+    rc = fts3WriteSegdir(
+        p, iLevel, iIdx, 0, 0, 0, pWriter->aData, pWriter->nData);
+  }
+  p->nLeafAdd++;
+  return rc;
+}
+
+/*
+** Release all memory held by the SegmentWriter object passed as the 
+** first argument.
+*/
+static void fts3SegWriterFree(SegmentWriter *pWriter){
+  if( pWriter ){
+    sqlite3_free(pWriter->aData);
+    sqlite3_free(pWriter->zMalloc);
+    fts3NodeFree(pWriter->pTree);
+    sqlite3_free(pWriter);
+  }
+}
+
+/*
+** The first value in the apVal[] array is assumed to contain an integer.
+** This function tests if there exist any documents with docid values that
+** are different from that integer. i.e. if deleting the document with docid
+** pRowid would mean the FTS3 table were empty.
+**
+** If successful, *pisEmpty is set to true if the table is empty except for
+** document pRowid, or false otherwise, and SQLITE_OK is returned. If an
+** error occurs, an SQLite error code is returned.
+*/
+static int fts3IsEmpty(Fts3Table *p, sqlite3_value *pRowid, int *pisEmpty){
+  sqlite3_stmt *pStmt;
+  int rc;
+  if( p->zContentTbl ){
+    /* If using the content=xxx option, assume the table is never empty */
+    *pisEmpty = 0;
+    rc = SQLITE_OK;
+  }else{
+    rc = fts3SqlStmt(p, SQL_IS_EMPTY, &pStmt, &pRowid);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        *pisEmpty = sqlite3_column_int(pStmt, 0);
+      }
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** Set *pnMax to the largest segment level in the database for the index
+** iIndex.
+**
+** Segment levels are stored in the 'level' column of the %_segdir table.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if not.
+*/
+static int fts3SegmentMaxLevel(
+  Fts3Table *p, 
+  int iLangid,
+  int iIndex, 
+  sqlite3_int64 *pnMax
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  /* Set pStmt to the compiled version of:
+  **
+  **   SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
+  **
+  ** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
+  */
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+  sqlite3_bind_int64(pStmt, 2, 
+      getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+  );
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    *pnMax = sqlite3_column_int64(pStmt, 0);
+  }
+  return sqlite3_reset(pStmt);
+}
+
+/*
+** Delete all entries in the %_segments table associated with the segment
+** opened with seg-reader pSeg. This function does not affect the contents
+** of the %_segdir table.
+*/
+static int fts3DeleteSegment(
+  Fts3Table *p,                   /* FTS table handle */
+  Fts3SegReader *pSeg             /* Segment to delete */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  if( pSeg->iStartBlock ){
+    sqlite3_stmt *pDelete;        /* SQL statement to delete rows */
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDelete, 1, pSeg->iStartBlock);
+      sqlite3_bind_int64(pDelete, 2, pSeg->iEndBlock);
+      sqlite3_step(pDelete);
+      rc = sqlite3_reset(pDelete);
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is used after merging multiple segments into a single large
+** segment to delete the old, now redundant, segment b-trees. Specifically,
+** it:
+** 
+**   1) Deletes all %_segments entries for the segments associated with 
+**      each of the SegReader objects in the array passed as the third 
+**      argument, and
+**
+**   2) deletes all %_segdir entries with level iLevel, or all %_segdir
+**      entries regardless of level if (iLevel<0).
+**
+** SQLITE_OK is returned if successful, otherwise an SQLite error code.
+*/
+static int fts3DeleteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index for p->aIndex */
+  int iLevel,                     /* Level of %_segdir entries to delete */
+  Fts3SegReader **apSegment,      /* Array of SegReader objects */
+  int nReader                     /* Size of array apSegment */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pDelete = 0;      /* SQL statement to delete rows */
+
+  for(i=0; rc==SQLITE_OK && i<nReader; i++){
+    rc = fts3DeleteSegment(p, apSegment[i]);
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  assert( iLevel>=0 || iLevel==FTS3_SEGCURSOR_ALL );
+  if( iLevel==FTS3_SEGCURSOR_ALL ){
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_RANGE, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+      sqlite3_bind_int64(pDelete, 2, 
+          getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+      );
+    }
+  }else{
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(
+          pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
+      );
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3_step(pDelete);
+    rc = sqlite3_reset(pDelete);
+  }
+
+  return rc;
+}
+
+/*
+** When this function is called, buffer *ppList (size *pnList bytes) contains 
+** a position list that may (or may not) feature multiple columns. This
+** function adjusts the pointer *ppList and the length *pnList so that they
+** identify the subset of the position list that corresponds to column iCol.
+**
+** If there are no entries in the input position list for column iCol, then
+** *pnList is set to zero before returning.
+*/
+static void fts3ColumnFilter(
+  int iCol,                       /* Column to filter on */
+  char **ppList,                  /* IN/OUT: Pointer to position list */
+  int *pnList                     /* IN/OUT: Size of buffer *ppList in bytes */
+){
+  char *pList = *ppList;
+  int nList = *pnList;
+  char *pEnd = &pList[nList];
+  int iCurrent = 0;
+  char *p = pList;
+
+  assert( iCol>=0 );
+  while( 1 ){
+    char c = 0;
+    while( p<pEnd && (c | *p)&0xFE ) c = *p++ & 0x80;
+  
+    if( iCol==iCurrent ){
+      nList = (int)(p - pList);
+      break;
+    }
+
+    nList -= (int)(p - pList);
+    pList = p;
+    if( nList==0 ){
+      break;
+    }
+    p = &pList[1];
+    p += sqlite3Fts3GetVarint32(p, &iCurrent);
+  }
+
+  *ppList = pList;
+  *pnList = nList;
+}
+
+/*
+** Cache data in the Fts3MultiSegReader.aBuffer[] buffer (overwriting any
+** existing data). Grow the buffer if required.
+**
+** If successful, return SQLITE_OK. Otherwise, if an OOM error is encountered
+** trying to resize the buffer, return SQLITE_NOMEM.
+*/
+static int fts3MsrBufferData(
+  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
+  char *pList,
+  int nList
+){
+  if( nList>pMsr->nBuffer ){
+    char *pNew;
+    pMsr->nBuffer = nList*2;
+    pNew = (char *)sqlite3_realloc(pMsr->aBuffer, pMsr->nBuffer);
+    if( !pNew ) return SQLITE_NOMEM;
+    pMsr->aBuffer = pNew;
+  }
+
+  memcpy(pMsr->aBuffer, pList, nList);
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
+  sqlite3_int64 *piDocid,         /* OUT: Docid value */
+  char **paPoslist,               /* OUT: Pointer to position list */
+  int *pnPoslist                  /* OUT: Size of position list in bytes */
+){
+  int nMerge = pMsr->nAdvance;
+  Fts3SegReader **apSegment = pMsr->apSegment;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  if( nMerge==0 ){
+    *paPoslist = 0;
+    return SQLITE_OK;
+  }
+
+  while( 1 ){
+    Fts3SegReader *pSeg;
+    pSeg = pMsr->apSegment[0];
+
+    if( pSeg->pOffsetList==0 ){
+      *paPoslist = 0;
+      break;
+    }else{
+      int rc;
+      char *pList;
+      int nList;
+      int j;
+      sqlite3_int64 iDocid = apSegment[0]->iDocid;
+
+      rc = fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
+      j = 1;
+      while( rc==SQLITE_OK 
+        && j<nMerge
+        && apSegment[j]->pOffsetList
+        && apSegment[j]->iDocid==iDocid
+      ){
+        rc = fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
+        j++;
+      }
+      if( rc!=SQLITE_OK ) return rc;
+      fts3SegReaderSort(pMsr->apSegment, nMerge, j, xCmp);
+
+      if( pMsr->iColFilter>=0 ){
+        fts3ColumnFilter(pMsr->iColFilter, &pList, &nList);
+      }
+
+      if( nList>0 ){
+        if( fts3SegReaderIsPending(apSegment[0]) ){
+          rc = fts3MsrBufferData(pMsr, pList, nList+1);
+          if( rc!=SQLITE_OK ) return rc;
+          *paPoslist = pMsr->aBuffer;
+          assert( (pMsr->aBuffer[nList] & 0xFE)==0x00 );
+        }else{
+          *paPoslist = pList;
+        }
+        *piDocid = iDocid;
+        *pnPoslist = nList;
+        break;
+      }
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+static int fts3SegReaderStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  const char *zTerm,              /* Term searched for (or NULL) */
+  int nTerm                       /* Length of zTerm in bytes */
+){
+  int i;
+  int nSeg = pCsr->nSegment;
+
+  /* If the Fts3SegFilter defines a specific term (or term prefix) to search 
+  ** for, then advance each segment iterator until it points to a term of
+  ** equal or greater value than the specified term. This prevents many
+  ** unnecessary merge/sort operations for the case where single segment
+  ** b-tree leaf nodes contain more than one term.
+  */
+  for(i=0; pCsr->bRestart==0 && i<pCsr->nSegment; i++){
+    int res = 0;
+    Fts3SegReader *pSeg = pCsr->apSegment[i];
+    do {
+      int rc = fts3SegReaderNext(p, pSeg, 0);
+      if( rc!=SQLITE_OK ) return rc;
+    }while( zTerm && (res = fts3SegReaderTermCmp(pSeg, zTerm, nTerm))<0 );
+
+    if( pSeg->bLookup && res!=0 ){
+      fts3SegReaderSetEof(pSeg);
+    }
+  }
+  fts3SegReaderSort(pCsr->apSegment, nSeg, nSeg, fts3SegReaderCmp);
+
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  Fts3SegFilter *pFilter          /* Restrictions on range of iteration */
+){
+  pCsr->pFilter = pFilter;
+  return fts3SegReaderStart(p, pCsr, pFilter->zTerm, pFilter->nTerm);
+}
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  int iCol,                       /* Column to match on. */
+  const char *zTerm,              /* Term to iterate through a doclist for */
+  int nTerm                       /* Number of bytes in zTerm */
+){
+  int i;
+  int rc;
+  int nSegment = pCsr->nSegment;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  assert( pCsr->pFilter==0 );
+  assert( zTerm && nTerm>0 );
+
+  /* Advance each segment iterator until it points to the term zTerm/nTerm. */
+  rc = fts3SegReaderStart(p, pCsr, zTerm, nTerm);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Determine how many of the segments actually point to zTerm/nTerm. */
+  for(i=0; i<nSegment; i++){
+    Fts3SegReader *pSeg = pCsr->apSegment[i];
+    if( !pSeg->aNode || fts3SegReaderTermCmp(pSeg, zTerm, nTerm) ){
+      break;
+    }
+  }
+  pCsr->nAdvance = i;
+
+  /* Advance each of the segments to point to the first docid. */
+  for(i=0; i<pCsr->nAdvance; i++){
+    rc = fts3SegReaderFirstDocid(p, pCsr->apSegment[i]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  fts3SegReaderSort(pCsr->apSegment, i, i, xCmp);
+
+  assert( iCol<0 || iCol<p->nColumn );
+  pCsr->iColFilter = iCol;
+
+  return SQLITE_OK;
+}
+
+/*
+** This function is called on a MultiSegReader that has been started using
+** sqlite3Fts3MsrIncrStart(). One or more calls to MsrIncrNext() may also
+** have been made. Calling this function puts the MultiSegReader in such
+** a state that if the next two calls are:
+**
+**   sqlite3Fts3SegReaderStart()
+**   sqlite3Fts3SegReaderStep()
+**
+** then the entire doclist for the term is available in 
+** MultiSegReader.aDoclist/nDoclist.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr){
+  int i;                          /* Used to iterate through segment-readers */
+
+  assert( pCsr->zTerm==0 );
+  assert( pCsr->nTerm==0 );
+  assert( pCsr->aDoclist==0 );
+  assert( pCsr->nDoclist==0 );
+
+  pCsr->nAdvance = 0;
+  pCsr->bRestart = 1;
+  for(i=0; i<pCsr->nSegment; i++){
+    pCsr->apSegment[i]->pOffsetList = 0;
+    pCsr->apSegment[i]->nOffsetList = 0;
+    pCsr->apSegment[i]->iDocid = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStep(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr        /* Cursor object */
+){
+  int rc = SQLITE_OK;
+
+  int isIgnoreEmpty =  (pCsr->pFilter->flags & FTS3_SEGMENT_IGNORE_EMPTY);
+  int isRequirePos =   (pCsr->pFilter->flags & FTS3_SEGMENT_REQUIRE_POS);
+  int isColFilter =    (pCsr->pFilter->flags & FTS3_SEGMENT_COLUMN_FILTER);
+  int isPrefix =       (pCsr->pFilter->flags & FTS3_SEGMENT_PREFIX);
+  int isScan =         (pCsr->pFilter->flags & FTS3_SEGMENT_SCAN);
+  int isFirst =        (pCsr->pFilter->flags & FTS3_SEGMENT_FIRST);
+
+  Fts3SegReader **apSegment = pCsr->apSegment;
+  int nSegment = pCsr->nSegment;
+  Fts3SegFilter *pFilter = pCsr->pFilter;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  if( pCsr->nSegment==0 ) return SQLITE_OK;
+
+  do {
+    int nMerge;
+    int i;
+  
+    /* Advance the first pCsr->nAdvance entries in the apSegment[] array
+    ** forward. Then sort the list in order of current term again.  
+    */
+    for(i=0; i<pCsr->nAdvance; i++){
+      Fts3SegReader *pSeg = apSegment[i];
+      if( pSeg->bLookup ){
+        fts3SegReaderSetEof(pSeg);
+      }else{
+        rc = fts3SegReaderNext(p, pSeg, 0);
+      }
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    fts3SegReaderSort(apSegment, nSegment, pCsr->nAdvance, fts3SegReaderCmp);
+    pCsr->nAdvance = 0;
+
+    /* If all the seg-readers are at EOF, we're finished. return SQLITE_OK. */
+    assert( rc==SQLITE_OK );
+    if( apSegment[0]->aNode==0 ) break;
+
+    pCsr->nTerm = apSegment[0]->nTerm;
+    pCsr->zTerm = apSegment[0]->zTerm;
+
+    /* If this is a prefix-search, and if the term that apSegment[0] points
+    ** to does not share a suffix with pFilter->zTerm/nTerm, then all 
+    ** required callbacks have been made. In this case exit early.
+    **
+    ** Similarly, if this is a search for an exact match, and the first term
+    ** of segment apSegment[0] is not a match, exit early.
+    */
+    if( pFilter->zTerm && !isScan ){
+      if( pCsr->nTerm<pFilter->nTerm 
+       || (!isPrefix && pCsr->nTerm>pFilter->nTerm)
+       || memcmp(pCsr->zTerm, pFilter->zTerm, pFilter->nTerm) 
+      ){
+        break;
+      }
+    }
+
+    nMerge = 1;
+    while( nMerge<nSegment 
+        && apSegment[nMerge]->aNode
+        && apSegment[nMerge]->nTerm==pCsr->nTerm 
+        && 0==memcmp(pCsr->zTerm, apSegment[nMerge]->zTerm, pCsr->nTerm)
+    ){
+      nMerge++;
+    }
+
+    assert( isIgnoreEmpty || (isRequirePos && !isColFilter) );
+    if( nMerge==1 
+     && !isIgnoreEmpty 
+     && !isFirst 
+     && (p->bDescIdx==0 || fts3SegReaderIsPending(apSegment[0])==0)
+    ){
+      pCsr->nDoclist = apSegment[0]->nDoclist;
+      if( fts3SegReaderIsPending(apSegment[0]) ){
+        rc = fts3MsrBufferData(pCsr, apSegment[0]->aDoclist, pCsr->nDoclist);
+        pCsr->aDoclist = pCsr->aBuffer;
+      }else{
+        pCsr->aDoclist = apSegment[0]->aDoclist;
+      }
+      if( rc==SQLITE_OK ) rc = SQLITE_ROW;
+    }else{
+      int nDoclist = 0;           /* Size of doclist */
+      sqlite3_int64 iPrev = 0;    /* Previous docid stored in doclist */
+
+      /* The current term of the first nMerge entries in the array
+      ** of Fts3SegReader objects is the same. The doclists must be merged
+      ** and a single term returned with the merged doclist.
+      */
+      for(i=0; i<nMerge; i++){
+        fts3SegReaderFirstDocid(p, apSegment[i]);
+      }
+      fts3SegReaderSort(apSegment, nMerge, nMerge, xCmp);
+      while( apSegment[0]->pOffsetList ){
+        int j;                    /* Number of segments that share a docid */
+        char *pList;
+        int nList;
+        int nByte;
+        sqlite3_int64 iDocid = apSegment[0]->iDocid;
+        fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
+        j = 1;
+        while( j<nMerge
+            && apSegment[j]->pOffsetList
+            && apSegment[j]->iDocid==iDocid
+        ){
+          fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
+          j++;
+        }
+
+        if( isColFilter ){
+          fts3ColumnFilter(pFilter->iCol, &pList, &nList);
+        }
+
+        if( !isIgnoreEmpty || nList>0 ){
+
+          /* Calculate the 'docid' delta value to write into the merged 
+          ** doclist. */
+          sqlite3_int64 iDelta;
+          if( p->bDescIdx && nDoclist>0 ){
+            iDelta = iPrev - iDocid;
+          }else{
+            iDelta = iDocid - iPrev;
+          }
+          assert( iDelta>0 || (nDoclist==0 && iDelta==iDocid) );
+          assert( nDoclist>0 || iDelta==iDocid );
+
+          nByte = sqlite3Fts3VarintLen(iDelta) + (isRequirePos?nList+1:0);
+          if( nDoclist+nByte>pCsr->nBuffer ){
+            char *aNew;
+            pCsr->nBuffer = (nDoclist+nByte)*2;
+            aNew = sqlite3_realloc(pCsr->aBuffer, pCsr->nBuffer);
+            if( !aNew ){
+              return SQLITE_NOMEM;
+            }
+            pCsr->aBuffer = aNew;
+          }
+
+          if( isFirst ){
+            char *a = &pCsr->aBuffer[nDoclist];
+            int nWrite;
+           
+            nWrite = sqlite3Fts3FirstFilter(iDelta, pList, nList, a);
+            if( nWrite ){
+              iPrev = iDocid;
+              nDoclist += nWrite;
+            }
+          }else{
+            nDoclist += sqlite3Fts3PutVarint(&pCsr->aBuffer[nDoclist], iDelta);
+            iPrev = iDocid;
+            if( isRequirePos ){
+              memcpy(&pCsr->aBuffer[nDoclist], pList, nList);
+              nDoclist += nList;
+              pCsr->aBuffer[nDoclist++] = '\0';
+            }
+          }
+        }
+
+        fts3SegReaderSort(apSegment, nMerge, j, xCmp);
+      }
+      if( nDoclist>0 ){
+        pCsr->aDoclist = pCsr->aBuffer;
+        pCsr->nDoclist = nDoclist;
+        rc = SQLITE_ROW;
+      }
+    }
+    pCsr->nAdvance = nMerge;
+  }while( rc==SQLITE_OK );
+
+  return rc;
+}
+
+
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFinish(
+  Fts3MultiSegReader *pCsr       /* Cursor object */
+){
+  if( pCsr ){
+    int i;
+    for(i=0; i<pCsr->nSegment; i++){
+      sqlite3Fts3SegReaderFree(pCsr->apSegment[i]);
+    }
+    sqlite3_free(pCsr->apSegment);
+    sqlite3_free(pCsr->aBuffer);
+
+    pCsr->nSegment = 0;
+    pCsr->apSegment = 0;
+    pCsr->aBuffer = 0;
+  }
+}
+
+/*
+** Merge all level iLevel segments in the database into a single 
+** iLevel+1 segment. Or, if iLevel<0, merge all segments into a
+** single segment with a level equal to the numerically largest level 
+** currently present in the database.
+**
+** If this function is called with iLevel<0, but there is only one
+** segment in the database, SQLITE_DONE is returned immediately. 
+** Otherwise, if successful, SQLITE_OK is returned. If an error occurs, 
+** an SQLite error code is returned.
+*/
+static int fts3SegmentMerge(
+  Fts3Table *p, 
+  int iLangid,                    /* Language id to merge */
+  int iIndex,                     /* Index in p->aIndex[] to merge */
+  int iLevel                      /* Level to merge */
+){
+  int rc;                         /* Return code */
+  int iIdx = 0;                   /* Index of new segment */
+  sqlite3_int64 iNewLevel = 0;    /* Level/index to create new segment at */
+  SegmentWriter *pWriter = 0;     /* Used to write the new, merged, segment */
+  Fts3SegFilter filter;           /* Segment term filter condition */
+  Fts3MultiSegReader csr;         /* Cursor to iterate through level(s) */
+  int bIgnoreEmpty = 0;           /* True to ignore empty segments */
+
+  assert( iLevel==FTS3_SEGCURSOR_ALL
+       || iLevel==FTS3_SEGCURSOR_PENDING
+       || iLevel>=0
+  );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  rc = sqlite3Fts3SegReaderCursor(p, iLangid, iIndex, iLevel, 0, 0, 1, 0, &csr);
+  if( rc!=SQLITE_OK || csr.nSegment==0 ) goto finished;
+
+  if( iLevel==FTS3_SEGCURSOR_ALL ){
+    /* This call is to merge all segments in the database to a single
+    ** segment. The level of the new segment is equal to the numerically
+    ** greatest segment level currently present in the database for this
+    ** index. The idx of the new segment is always 0.  */
+    if( csr.nSegment==1 ){
+      rc = SQLITE_DONE;
+      goto finished;
+    }
+    rc = fts3SegmentMaxLevel(p, iLangid, iIndex, &iNewLevel);
+    bIgnoreEmpty = 1;
+
+  }else if( iLevel==FTS3_SEGCURSOR_PENDING ){
+    iNewLevel = getAbsoluteLevel(p, iLangid, iIndex, 0);
+    rc = fts3AllocateSegdirIdx(p, iLangid, iIndex, 0, &iIdx);
+  }else{
+    /* This call is to merge all segments at level iLevel. find the next
+    ** available segment index at level iLevel+1. The call to
+    ** fts3AllocateSegdirIdx() will merge the segments at level iLevel+1 to 
+    ** a single iLevel+2 segment if necessary.  */
+    rc = fts3AllocateSegdirIdx(p, iLangid, iIndex, iLevel+1, &iIdx);
+    iNewLevel = getAbsoluteLevel(p, iLangid, iIndex, iLevel+1);
+  }
+  if( rc!=SQLITE_OK ) goto finished;
+  assert( csr.nSegment>0 );
+  assert( iNewLevel>=getAbsoluteLevel(p, iLangid, iIndex, 0) );
+  assert( iNewLevel<getAbsoluteLevel(p, iLangid, iIndex,FTS3_SEGDIR_MAXLEVEL) );
+
+  memset(&filter, 0, sizeof(Fts3SegFilter));
+  filter.flags = FTS3_SEGMENT_REQUIRE_POS;
+  filter.flags |= (bIgnoreEmpty ? FTS3_SEGMENT_IGNORE_EMPTY : 0);
+
+  rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
+  while( SQLITE_OK==rc ){
+    rc = sqlite3Fts3SegReaderStep(p, &csr);
+    if( rc!=SQLITE_ROW ) break;
+    rc = fts3SegWriterAdd(p, &pWriter, 1, 
+        csr.zTerm, csr.nTerm, csr.aDoclist, csr.nDoclist);
+  }
+  if( rc!=SQLITE_OK ) goto finished;
+  assert( pWriter );
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    rc = fts3DeleteSegdir(
+        p, iLangid, iIndex, iLevel, csr.apSegment, csr.nSegment
+    );
+    if( rc!=SQLITE_OK ) goto finished;
+  }
+  rc = fts3SegWriterFlush(p, pWriter, iNewLevel, iIdx);
+
+ finished:
+  fts3SegWriterFree(pWriter);
+  sqlite3Fts3SegReaderFinish(&csr);
+  return rc;
+}
+
+
+/* 
+** Flush the contents of pendingTerms to level 0 segments.
+*/
+SQLITE_PRIVATE int sqlite3Fts3PendingTermsFlush(Fts3Table *p){
+  int rc = SQLITE_OK;
+  int i;
+        
+  for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
+    rc = fts3SegmentMerge(p, p->iPrevLangid, i, FTS3_SEGCURSOR_PENDING);
+    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  }
+  sqlite3Fts3PendingTermsClear(p);
+
+  /* Determine the auto-incr-merge setting if unknown.  If enabled,
+  ** estimate the number of leaf blocks of content to be written
+  */
+  if( rc==SQLITE_OK && p->bHasStat
+   && p->bAutoincrmerge==0xff && p->nLeafAdd>0
+  ){
+    sqlite3_stmt *pStmt = 0;
+    rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
+      rc = sqlite3_step(pStmt);
+      p->bAutoincrmerge = (rc==SQLITE_ROW && sqlite3_column_int(pStmt, 0));
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** Encode N integers as varints into a blob.
+*/
+static void fts3EncodeIntArray(
+  int N,             /* The number of integers to encode */
+  u32 *a,            /* The integer values */
+  char *zBuf,        /* Write the BLOB here */
+  int *pNBuf         /* Write number of bytes if zBuf[] used here */
+){
+  int i, j;
+  for(i=j=0; i<N; i++){
+    j += sqlite3Fts3PutVarint(&zBuf[j], (sqlite3_int64)a[i]);
+  }
+  *pNBuf = j;
+}
+
+/*
+** Decode a blob of varints into N integers
+*/
+static void fts3DecodeIntArray(
+  int N,             /* The number of integers to decode */
+  u32 *a,            /* Write the integer values */
+  const char *zBuf,  /* The BLOB containing the varints */
+  int nBuf           /* size of the BLOB */
+){
+  int i, j;
+  UNUSED_PARAMETER(nBuf);
+  for(i=j=0; i<N; i++){
+    sqlite3_int64 x;
+    j += sqlite3Fts3GetVarint(&zBuf[j], &x);
+    assert(j<=nBuf);
+    a[i] = (u32)(x & 0xffffffff);
+  }
+}
+
+/*
+** Insert the sizes (in tokens) for each column of the document
+** with docid equal to p->iPrevDocid.  The sizes are encoded as
+** a blob of varints.
+*/
+static void fts3InsertDocsize(
+  int *pRC,                       /* Result code */
+  Fts3Table *p,                   /* Table into which to insert */
+  u32 *aSz                        /* Sizes of each column, in tokens */
+){
+  char *pBlob;             /* The BLOB encoding of the document size */
+  int nBlob;               /* Number of bytes in the BLOB */
+  sqlite3_stmt *pStmt;     /* Statement used to insert the encoding */
+  int rc;                  /* Result code from subfunctions */
+
+  if( *pRC ) return;
+  pBlob = sqlite3_malloc( 10*p->nColumn );
+  if( pBlob==0 ){
+    *pRC = SQLITE_NOMEM;
+    return;
+  }
+  fts3EncodeIntArray(p->nColumn, aSz, pBlob, &nBlob);
+  rc = fts3SqlStmt(p, SQL_REPLACE_DOCSIZE, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(pBlob);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int64(pStmt, 1, p->iPrevDocid);
+  sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, sqlite3_free);
+  sqlite3_step(pStmt);
+  *pRC = sqlite3_reset(pStmt);
+}
+
+/*
+** Record 0 of the %_stat table contains a blob consisting of N varints,
+** where N is the number of user defined columns in the fts3 table plus
+** two. If nCol is the number of user defined columns, then values of the 
+** varints are set as follows:
+**
+**   Varint 0:       Total number of rows in the table.
+**
+**   Varint 1..nCol: For each column, the total number of tokens stored in
+**                   the column for all rows of the table.
+**
+**   Varint 1+nCol:  The total size, in bytes, of all text values in all
+**                   columns of all rows of the table.
+**
+*/
+static void fts3UpdateDocTotals(
+  int *pRC,                       /* The result code */
+  Fts3Table *p,                   /* Table being updated */
+  u32 *aSzIns,                    /* Size increases */
+  u32 *aSzDel,                    /* Size decreases */
+  int nChng                       /* Change in the number of documents */
+){
+  char *pBlob;             /* Storage for BLOB written into %_stat */
+  int nBlob;               /* Size of BLOB written into %_stat */
+  u32 *a;                  /* Array of integers that becomes the BLOB */
+  sqlite3_stmt *pStmt;     /* Statement for reading and writing */
+  int i;                   /* Loop counter */
+  int rc;                  /* Result code from subfunctions */
+
+  const int nStat = p->nColumn+2;
+
+  if( *pRC ) return;
+  a = sqlite3_malloc( (sizeof(u32)+10)*nStat );
+  if( a==0 ){
+    *pRC = SQLITE_NOMEM;
+    return;
+  }
+  pBlob = (char*)&a[nStat];
+  rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+  if( sqlite3_step(pStmt)==SQLITE_ROW ){
+    fts3DecodeIntArray(nStat, a,
+         sqlite3_column_blob(pStmt, 0),
+         sqlite3_column_bytes(pStmt, 0));
+  }else{
+    memset(a, 0, sizeof(u32)*(nStat) );
+  }
+  rc = sqlite3_reset(pStmt);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  if( nChng<0 && a[0]<(u32)(-nChng) ){
+    a[0] = 0;
+  }else{
+    a[0] += nChng;
+  }
+  for(i=0; i<p->nColumn+1; i++){
+    u32 x = a[i+1];
+    if( x+aSzIns[i] < aSzDel[i] ){
+      x = 0;
+    }else{
+      x = x + aSzIns[i] - aSzDel[i];
+    }
+    a[i+1] = x;
+  }
+  fts3EncodeIntArray(nStat, a, pBlob, &nBlob);
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+  sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, SQLITE_STATIC);
+  sqlite3_step(pStmt);
+  *pRC = sqlite3_reset(pStmt);
+  sqlite3_free(a);
+}
+
+/*
+** Merge the entire database so that there is one segment for each 
+** iIndex/iLangid combination.
+*/
+static int fts3DoOptimize(Fts3Table *p, int bReturnDone){
+  int bSeenDone = 0;
+  int rc;
+  sqlite3_stmt *pAllLangid = 0;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pAllLangid, 1, p->nIndex);
+    while( sqlite3_step(pAllLangid)==SQLITE_ROW ){
+      int i;
+      int iLangid = sqlite3_column_int(pAllLangid, 0);
+      for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
+        rc = fts3SegmentMerge(p, iLangid, i, FTS3_SEGCURSOR_ALL);
+        if( rc==SQLITE_DONE ){
+          bSeenDone = 1;
+          rc = SQLITE_OK;
+        }
+      }
+    }
+    rc2 = sqlite3_reset(pAllLangid);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  sqlite3Fts3SegmentsClose(p);
+  sqlite3Fts3PendingTermsClear(p);
+
+  return (rc==SQLITE_OK && bReturnDone && bSeenDone) ? SQLITE_DONE : rc;
+}
+
+/*
+** This function is called when the user executes the following statement:
+**
+**     INSERT INTO <tbl>(<tbl>) VALUES('rebuild');
+**
+** The entire FTS index is discarded and rebuilt. If the table is one 
+** created using the content=xxx option, then the new index is based on
+** the current contents of the xxx table. Otherwise, it is rebuilt based
+** on the contents of the %_content table.
+*/
+static int fts3DoRebuild(Fts3Table *p){
+  int rc;                         /* Return Code */
+
+  rc = fts3DeleteAll(p, 0);
+  if( rc==SQLITE_OK ){
+    u32 *aSz = 0;
+    u32 *aSzIns = 0;
+    u32 *aSzDel = 0;
+    sqlite3_stmt *pStmt = 0;
+    int nEntry = 0;
+
+    /* Compose and prepare an SQL statement to loop through the content table */
+    char *zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
+      sqlite3_free(zSql);
+    }
+
+    if( rc==SQLITE_OK ){
+      int nByte = sizeof(u32) * (p->nColumn+1)*3;
+      aSz = (u32 *)sqlite3_malloc(nByte);
+      if( aSz==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(aSz, 0, nByte);
+        aSzIns = &aSz[p->nColumn+1];
+        aSzDel = &aSzIns[p->nColumn+1];
+      }
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      int iCol;
+      int iLangid = langidFromSelect(p, pStmt);
+      rc = fts3PendingTermsDocid(p, iLangid, sqlite3_column_int64(pStmt, 0));
+      aSz[p->nColumn] = 0;
+      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
+        const char *z = (const char *) sqlite3_column_text(pStmt, iCol+1);
+        rc = fts3PendingTermsAdd(p, iLangid, z, iCol, &aSz[iCol]);
+        aSz[p->nColumn] += sqlite3_column_bytes(pStmt, iCol+1);
+      }
+      if( p->bHasDocsize ){
+        fts3InsertDocsize(&rc, p, aSz);
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_finalize(pStmt);
+        pStmt = 0;
+      }else{
+        nEntry++;
+        for(iCol=0; iCol<=p->nColumn; iCol++){
+          aSzIns[iCol] += aSz[iCol];
+        }
+      }
+    }
+    if( p->bFts4 ){
+      fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nEntry);
+    }
+    sqlite3_free(aSz);
+
+    if( pStmt ){
+      int rc2 = sqlite3_finalize(pStmt);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+/*
+** This function opens a cursor used to read the input data for an 
+** incremental merge operation. Specifically, it opens a cursor to scan
+** the oldest nSeg segments (idx=0 through idx=(nSeg-1)) in absolute 
+** level iAbsLevel.
+*/
+static int fts3IncrmergeCsr(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level to open */
+  int nSeg,                       /* Number of segments to merge */
+  Fts3MultiSegReader *pCsr        /* Cursor object to populate */
+){
+  int rc;                         /* Return Code */
+  sqlite3_stmt *pStmt = 0;        /* Statement used to read %_segdir entry */  
+  int nByte;                      /* Bytes allocated at pCsr->apSegment[] */
+
+  /* Allocate space for the Fts3MultiSegReader.aCsr[] array */
+  memset(pCsr, 0, sizeof(*pCsr));
+  nByte = sizeof(Fts3SegReader *) * nSeg;
+  pCsr->apSegment = (Fts3SegReader **)sqlite3_malloc(nByte);
+
+  if( pCsr->apSegment==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(pCsr->apSegment, 0, nByte);
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
+  }
+  if( rc==SQLITE_OK ){
+    int i;
+    int rc2;
+    sqlite3_bind_int64(pStmt, 1, iAbsLevel);
+    assert( pCsr->nSegment==0 );
+    for(i=0; rc==SQLITE_OK && sqlite3_step(pStmt)==SQLITE_ROW && i<nSeg; i++){
+      rc = sqlite3Fts3SegReaderNew(i, 0,
+          sqlite3_column_int64(pStmt, 1),        /* segdir.start_block */
+          sqlite3_column_int64(pStmt, 2),        /* segdir.leaves_end_block */
+          sqlite3_column_int64(pStmt, 3),        /* segdir.end_block */
+          sqlite3_column_blob(pStmt, 4),         /* segdir.root */
+          sqlite3_column_bytes(pStmt, 4),        /* segdir.root */
+          &pCsr->apSegment[i]
+      );
+      pCsr->nSegment++;
+    }
+    rc2 = sqlite3_reset(pStmt);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+typedef struct IncrmergeWriter IncrmergeWriter;
+typedef struct NodeWriter NodeWriter;
+typedef struct Blob Blob;
+typedef struct NodeReader NodeReader;
+
+/*
+** An instance of the following structure is used as a dynamic buffer
+** to build up nodes or other blobs of data in.
+**
+** The function blobGrowBuffer() is used to extend the allocation.
+*/
+struct Blob {
+  char *a;                        /* Pointer to allocation */
+  int n;                          /* Number of valid bytes of data in a[] */
+  int nAlloc;                     /* Allocated size of a[] (nAlloc>=n) */
+};
+
+/*
+** This structure is used to build up buffers containing segment b-tree 
+** nodes (blocks).
+*/
+struct NodeWriter {
+  sqlite3_int64 iBlock;           /* Current block id */
+  Blob key;                       /* Last key written to the current block */
+  Blob block;                     /* Current block image */
+};
+
+/*
+** An object of this type contains the state required to create or append
+** to an appendable b-tree segment.
+*/
+struct IncrmergeWriter {
+  int nLeafEst;                   /* Space allocated for leaf blocks */
+  int nWork;                      /* Number of leaf pages flushed */
+  sqlite3_int64 iAbsLevel;        /* Absolute level of input segments */
+  int iIdx;                       /* Index of *output* segment in iAbsLevel+1 */
+  sqlite3_int64 iStart;           /* Block number of first allocated block */
+  sqlite3_int64 iEnd;             /* Block number of last allocated block */
+  NodeWriter aNodeWriter[FTS_MAX_APPENDABLE_HEIGHT];
+};
+
+/*
+** An object of the following type is used to read data from a single
+** FTS segment node. See the following functions:
+**
+**     nodeReaderInit()
+**     nodeReaderNext()
+**     nodeReaderRelease()
+*/
+struct NodeReader {
+  const char *aNode;
+  int nNode;
+  int iOff;                       /* Current offset within aNode[] */
+
+  /* Output variables. Containing the current node entry. */
+  sqlite3_int64 iChild;           /* Pointer to child node */
+  Blob term;                      /* Current term */
+  const char *aDoclist;           /* Pointer to doclist */
+  int nDoclist;                   /* Size of doclist in bytes */
+};
+
+/*
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, if the allocation at pBlob->a is not already at least nMin
+** bytes in size, extend (realloc) it to be so.
+**
+** If an OOM error occurs, set *pRc to SQLITE_NOMEM and leave pBlob->a
+** unmodified. Otherwise, if the allocation succeeds, update pBlob->nAlloc
+** to reflect the new size of the pBlob->a[] buffer.
+*/
+static void blobGrowBuffer(Blob *pBlob, int nMin, int *pRc){
+  if( *pRc==SQLITE_OK && nMin>pBlob->nAlloc ){
+    int nAlloc = nMin;
+    char *a = (char *)sqlite3_realloc(pBlob->a, nAlloc);
+    if( a ){
+      pBlob->nAlloc = nAlloc;
+      pBlob->a = a;
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+}
+
+/*
+** Attempt to advance the node-reader object passed as the first argument to
+** the next entry on the node. 
+**
+** Return an error code if an error occurs (SQLITE_NOMEM is possible). 
+** Otherwise return SQLITE_OK. If there is no next entry on the node
+** (e.g. because the current entry is the last) set NodeReader->aNode to
+** NULL to indicate EOF. Otherwise, populate the NodeReader structure output 
+** variables for the new entry.
+*/
+static int nodeReaderNext(NodeReader *p){
+  int bFirst = (p->term.n==0);    /* True for first term on the node */
+  int nPrefix = 0;                /* Bytes to copy from previous term */
+  int nSuffix = 0;                /* Bytes to append to the prefix */
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( p->aNode );
+  if( p->iChild && bFirst==0 ) p->iChild++;
+  if( p->iOff>=p->nNode ){
+    /* EOF */
+    p->aNode = 0;
+  }else{
+    if( bFirst==0 ){
+      p->iOff += sqlite3Fts3GetVarint32(&p->aNode[p->iOff], &nPrefix);
+    }
+    p->iOff += sqlite3Fts3GetVarint32(&p->aNode[p->iOff], &nSuffix);
+
+    blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
+    if( rc==SQLITE_OK ){
+      memcpy(&p->term.a[nPrefix], &p->aNode[p->iOff], nSuffix);
+      p->term.n = nPrefix+nSuffix;
+      p->iOff += nSuffix;
+      if( p->iChild==0 ){
+        p->iOff += sqlite3Fts3GetVarint32(&p->aNode[p->iOff], &p->nDoclist);
+        p->aDoclist = &p->aNode[p->iOff];
+        p->iOff += p->nDoclist;
+      }
+    }
+  }
+
+  assert( p->iOff<=p->nNode );
+
+  return rc;
+}
+
+/*
+** Release all dynamic resources held by node-reader object *p.
+*/
+static void nodeReaderRelease(NodeReader *p){
+  sqlite3_free(p->term.a);
+}
+
+/*
+** Initialize a node-reader object to read the node in buffer aNode/nNode.
+**
+** If successful, SQLITE_OK is returned and the NodeReader object set to 
+** point to the first entry on the node (if any). Otherwise, an SQLite
+** error code is returned.
+*/
+static int nodeReaderInit(NodeReader *p, const char *aNode, int nNode){
+  memset(p, 0, sizeof(NodeReader));
+  p->aNode = aNode;
+  p->nNode = nNode;
+
+  /* Figure out if this is a leaf or an internal node. */
+  if( p->aNode[0] ){
+    /* An internal node. */
+    p->iOff = 1 + sqlite3Fts3GetVarint(&p->aNode[1], &p->iChild);
+  }else{
+    p->iOff = 1;
+  }
+
+  return nodeReaderNext(p);
+}
+
+/*
+** This function is called while writing an FTS segment each time a leaf o
+** node is finished and written to disk. The key (zTerm/nTerm) is guaranteed
+** to be greater than the largest key on the node just written, but smaller
+** than or equal to the first key that will be written to the next leaf
+** node.
+**
+** The block id of the leaf node just written to disk may be found in
+** (pWriter->aNodeWriter[0].iBlock) when this function is called.
+*/
+static int fts3IncrmergePush(
+  Fts3Table *p,                   /* Fts3 table handle */
+  IncrmergeWriter *pWriter,       /* Writer object */
+  const char *zTerm,              /* Term to write to internal node */
+  int nTerm                       /* Bytes at zTerm */
+){
+  sqlite3_int64 iPtr = pWriter->aNodeWriter[0].iBlock;
+  int iLayer;
+
+  assert( nTerm>0 );
+  for(iLayer=1; ALWAYS(iLayer<FTS_MAX_APPENDABLE_HEIGHT); iLayer++){
+    sqlite3_int64 iNextPtr = 0;
+    NodeWriter *pNode = &pWriter->aNodeWriter[iLayer];
+    int rc = SQLITE_OK;
+    int nPrefix;
+    int nSuffix;
+    int nSpace;
+
+    /* Figure out how much space the key will consume if it is written to
+    ** the current node of layer iLayer. Due to the prefix compression, 
+    ** the space required changes depending on which node the key is to
+    ** be added to.  */
+    nPrefix = fts3PrefixCompress(pNode->key.a, pNode->key.n, zTerm, nTerm);
+    nSuffix = nTerm - nPrefix;
+    nSpace  = sqlite3Fts3VarintLen(nPrefix);
+    nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+
+    if( pNode->key.n==0 || (pNode->block.n + nSpace)<=p->nNodeSize ){ 
+      /* If the current node of layer iLayer contains zero keys, or if adding
+      ** the key to it will not cause it to grow to larger than nNodeSize 
+      ** bytes in size, write the key here.  */
+
+      Blob *pBlk = &pNode->block;
+      if( pBlk->n==0 ){
+        blobGrowBuffer(pBlk, p->nNodeSize, &rc);
+        if( rc==SQLITE_OK ){
+          pBlk->a[0] = (char)iLayer;
+          pBlk->n = 1 + sqlite3Fts3PutVarint(&pBlk->a[1], iPtr);
+        }
+      }
+      blobGrowBuffer(pBlk, pBlk->n + nSpace, &rc);
+      blobGrowBuffer(&pNode->key, nTerm, &rc);
+
+      if( rc==SQLITE_OK ){
+        if( pNode->key.n ){
+          pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nPrefix);
+        }
+        pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nSuffix);
+        memcpy(&pBlk->a[pBlk->n], &zTerm[nPrefix], nSuffix);
+        pBlk->n += nSuffix;
+
+        memcpy(pNode->key.a, zTerm, nTerm);
+        pNode->key.n = nTerm;
+      }
+    }else{
+      /* Otherwise, flush the current node of layer iLayer to disk.
+      ** Then allocate a new, empty sibling node. The key will be written
+      ** into the parent of this node. */
+      rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
+
+      assert( pNode->block.nAlloc>=p->nNodeSize );
+      pNode->block.a[0] = (char)iLayer;
+      pNode->block.n = 1 + sqlite3Fts3PutVarint(&pNode->block.a[1], iPtr+1);
+
+      iNextPtr = pNode->iBlock;
+      pNode->iBlock++;
+      pNode->key.n = 0;
+    }
+
+    if( rc!=SQLITE_OK || iNextPtr==0 ) return rc;
+    iPtr = iNextPtr;
+  }
+
+  assert( 0 );
+  return 0;
+}
+
+/*
+** Append a term and (optionally) doclist to the FTS segment node currently
+** stored in blob *pNode. The node need not contain any terms, but the
+** header must be written before this function is called.
+**
+** A node header is a single 0x00 byte for a leaf node, or a height varint
+** followed by the left-hand-child varint for an internal node.
+**
+** The term to be appended is passed via arguments zTerm/nTerm. For a 
+** leaf node, the doclist is passed as aDoclist/nDoclist. For an internal
+** node, both aDoclist and nDoclist must be passed 0.
+**
+** If the size of the value in blob pPrev is zero, then this is the first
+** term written to the node. Otherwise, pPrev contains a copy of the 
+** previous term. Before this function returns, it is updated to contain a
+** copy of zTerm/nTerm.
+**
+** It is assumed that the buffer associated with pNode is already large
+** enough to accommodate the new entry. The buffer associated with pPrev
+** is extended by this function if requrired.
+**
+** If an error (i.e. OOM condition) occurs, an SQLite error code is
+** returned. Otherwise, SQLITE_OK.
+*/
+static int fts3AppendToNode(
+  Blob *pNode,                    /* Current node image to append to */
+  Blob *pPrev,                    /* Buffer containing previous term written */
+  const char *zTerm,              /* New term to write */
+  int nTerm,                      /* Size of zTerm in bytes */
+  const char *aDoclist,           /* Doclist (or NULL) to write */
+  int nDoclist                    /* Size of aDoclist in bytes */ 
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int bFirst = (pPrev->n==0);     /* True if this is the first term written */
+  int nPrefix;                    /* Size of term prefix in bytes */
+  int nSuffix;                    /* Size of term suffix in bytes */
+
+  /* Node must have already been started. There must be a doclist for a
+  ** leaf node, and there must not be a doclist for an internal node.  */
+  assert( pNode->n>0 );
+  assert( (pNode->a[0]=='\0')==(aDoclist!=0) );
+
+  blobGrowBuffer(pPrev, nTerm, &rc);
+  if( rc!=SQLITE_OK ) return rc;
+
+  nPrefix = fts3PrefixCompress(pPrev->a, pPrev->n, zTerm, nTerm);
+  nSuffix = nTerm - nPrefix;
+  memcpy(pPrev->a, zTerm, nTerm);
+  pPrev->n = nTerm;
+
+  if( bFirst==0 ){
+    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nPrefix);
+  }
+  pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nSuffix);
+  memcpy(&pNode->a[pNode->n], &zTerm[nPrefix], nSuffix);
+  pNode->n += nSuffix;
+
+  if( aDoclist ){
+    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nDoclist);
+    memcpy(&pNode->a[pNode->n], aDoclist, nDoclist);
+    pNode->n += nDoclist;
+  }
+
+  assert( pNode->n<=pNode->nAlloc );
+
+  return SQLITE_OK;
+}
+
+/*
+** Append the current term and doclist pointed to by cursor pCsr to the
+** appendable b-tree segment opened for writing by pWriter.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int fts3IncrmergeAppend(
+  Fts3Table *p,                   /* Fts3 table handle */
+  IncrmergeWriter *pWriter,       /* Writer object */
+  Fts3MultiSegReader *pCsr        /* Cursor containing term and doclist */
+){
+  const char *zTerm = pCsr->zTerm;
+  int nTerm = pCsr->nTerm;
+  const char *aDoclist = pCsr->aDoclist;
+  int nDoclist = pCsr->nDoclist;
+  int rc = SQLITE_OK;           /* Return code */
+  int nSpace;                   /* Total space in bytes required on leaf */
+  int nPrefix;                  /* Size of prefix shared with previous term */
+  int nSuffix;                  /* Size of suffix (nTerm - nPrefix) */
+  NodeWriter *pLeaf;            /* Object used to write leaf nodes */
+
+  pLeaf = &pWriter->aNodeWriter[0];
+  nPrefix = fts3PrefixCompress(pLeaf->key.a, pLeaf->key.n, zTerm, nTerm);
+  nSuffix = nTerm - nPrefix;
+
+  nSpace  = sqlite3Fts3VarintLen(nPrefix);
+  nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+  nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
+
+  /* If the current block is not empty, and if adding this term/doclist
+  ** to the current block would make it larger than Fts3Table.nNodeSize
+  ** bytes, write this block out to the database. */
+  if( pLeaf->block.n>0 && (pLeaf->block.n + nSpace)>p->nNodeSize ){
+    rc = fts3WriteSegment(p, pLeaf->iBlock, pLeaf->block.a, pLeaf->block.n);
+    pWriter->nWork++;
+
+    /* Add the current term to the parent node. The term added to the 
+    ** parent must:
+    **
+    **   a) be greater than the largest term on the leaf node just written
+    **      to the database (still available in pLeaf->key), and
+    **
+    **   b) be less than or equal to the term about to be added to the new
+    **      leaf node (zTerm/nTerm).
+    **
+    ** In other words, it must be the prefix of zTerm 1 byte longer than
+    ** the common prefix (if any) of zTerm and pWriter->zTerm.
+    */
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergePush(p, pWriter, zTerm, nPrefix+1);
+    }
+
+    /* Advance to the next output block */
+    pLeaf->iBlock++;
+    pLeaf->key.n = 0;
+    pLeaf->block.n = 0;
+
+    nSuffix = nTerm;
+    nSpace  = 1;
+    nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+    nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
+  }
+
+  blobGrowBuffer(&pLeaf->block, pLeaf->block.n + nSpace, &rc);
+
+  if( rc==SQLITE_OK ){
+    if( pLeaf->block.n==0 ){
+      pLeaf->block.n = 1;
+      pLeaf->block.a[0] = '\0';
+    }
+    rc = fts3AppendToNode(
+        &pLeaf->block, &pLeaf->key, zTerm, nTerm, aDoclist, nDoclist
+    );
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to release all dynamic resources held by the
+** merge-writer object pWriter, and if no error has occurred, to flush
+** all outstanding node buffers held by pWriter to disk.
+**
+** If *pRc is not SQLITE_OK when this function is called, then no attempt
+** is made to write any data to disk. Instead, this function serves only
+** to release outstanding resources.
+**
+** Otherwise, if *pRc is initially SQLITE_OK and an error occurs while
+** flushing buffers to disk, *pRc is set to an SQLite error code before
+** returning.
+*/
+static void fts3IncrmergeRelease(
+  Fts3Table *p,                   /* FTS3 table handle */
+  IncrmergeWriter *pWriter,       /* Merge-writer object */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int i;                          /* Used to iterate through non-root layers */
+  int iRoot;                      /* Index of root in pWriter->aNodeWriter */
+  NodeWriter *pRoot;              /* NodeWriter for root node */
+  int rc = *pRc;                  /* Error code */
+
+  /* Set iRoot to the index in pWriter->aNodeWriter[] of the output segment 
+  ** root node. If the segment fits entirely on a single leaf node, iRoot
+  ** will be set to 0. If the root node is the parent of the leaves, iRoot
+  ** will be 1. And so on.  */
+  for(iRoot=FTS_MAX_APPENDABLE_HEIGHT-1; iRoot>=0; iRoot--){
+    NodeWriter *pNode = &pWriter->aNodeWriter[iRoot];
+    if( pNode->block.n>0 ) break;
+    assert( *pRc || pNode->block.nAlloc==0 );
+    assert( *pRc || pNode->key.nAlloc==0 );
+    sqlite3_free(pNode->block.a);
+    sqlite3_free(pNode->key.a);
+  }
+
+  /* Empty output segment. This is a no-op. */
+  if( iRoot<0 ) return;
+
+  /* The entire output segment fits on a single node. Normally, this means
+  ** the node would be stored as a blob in the "root" column of the %_segdir
+  ** table. However, this is not permitted in this case. The problem is that 
+  ** space has already been reserved in the %_segments table, and so the 
+  ** start_block and end_block fields of the %_segdir table must be populated. 
+  ** And, by design or by accident, released versions of FTS cannot handle 
+  ** segments that fit entirely on the root node with start_block!=0.
+  **
+  ** Instead, create a synthetic root node that contains nothing but a 
+  ** pointer to the single content node. So that the segment consists of a
+  ** single leaf and a single interior (root) node.
+  **
+  ** Todo: Better might be to defer allocating space in the %_segments 
+  ** table until we are sure it is needed.
+  */
+  if( iRoot==0 ){
+    Blob *pBlock = &pWriter->aNodeWriter[1].block;
+    blobGrowBuffer(pBlock, 1 + FTS3_VARINT_MAX, &rc);
+    if( rc==SQLITE_OK ){
+      pBlock->a[0] = 0x01;
+      pBlock->n = 1 + sqlite3Fts3PutVarint(
+          &pBlock->a[1], pWriter->aNodeWriter[0].iBlock
+      );
+    }
+    iRoot = 1;
+  }
+  pRoot = &pWriter->aNodeWriter[iRoot];
+
+  /* Flush all currently outstanding nodes to disk. */
+  for(i=0; i<iRoot; i++){
+    NodeWriter *pNode = &pWriter->aNodeWriter[i];
+    if( pNode->block.n>0 && rc==SQLITE_OK ){
+      rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
+    }
+    sqlite3_free(pNode->block.a);
+    sqlite3_free(pNode->key.a);
+  }
+
+  /* Write the %_segdir record. */
+  if( rc==SQLITE_OK ){
+    rc = fts3WriteSegdir(p, 
+        pWriter->iAbsLevel+1,               /* level */
+        pWriter->iIdx,                      /* idx */
+        pWriter->iStart,                    /* start_block */
+        pWriter->aNodeWriter[0].iBlock,     /* leaves_end_block */
+        pWriter->iEnd,                      /* end_block */
+        pRoot->block.a, pRoot->block.n      /* root */
+    );
+  }
+  sqlite3_free(pRoot->block.a);
+  sqlite3_free(pRoot->key.a);
+
+  *pRc = rc;
+}
+
+/*
+** Compare the term in buffer zLhs (size in bytes nLhs) with that in
+** zRhs (size in bytes nRhs) using memcmp. If one term is a prefix of
+** the other, it is considered to be smaller than the other.
+**
+** Return -ve if zLhs is smaller than zRhs, 0 if it is equal, or +ve
+** if it is greater.
+*/
+static int fts3TermCmp(
+  const char *zLhs, int nLhs,     /* LHS of comparison */
+  const char *zRhs, int nRhs      /* RHS of comparison */
+){
+  int nCmp = MIN(nLhs, nRhs);
+  int res;
+
+  res = memcmp(zLhs, zRhs, nCmp);
+  if( res==0 ) res = nLhs - nRhs;
+
+  return res;
+}
+
+
+/*
+** Query to see if the entry in the %_segments table with blockid iEnd is 
+** NULL. If no error occurs and the entry is NULL, set *pbRes 1 before
+** returning. Otherwise, set *pbRes to 0. 
+**
+** Or, if an error occurs while querying the database, return an SQLite 
+** error code. The final value of *pbRes is undefined in this case.
+**
+** This is used to test if a segment is an "appendable" segment. If it
+** is, then a NULL entry has been inserted into the %_segments table
+** with blockid %_segdir.end_block.
+*/
+static int fts3IsAppendable(Fts3Table *p, sqlite3_int64 iEnd, int *pbRes){
+  int bRes = 0;                   /* Result to set *pbRes to */
+  sqlite3_stmt *pCheck = 0;       /* Statement to query database with */
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(p, SQL_SEGMENT_IS_APPENDABLE, &pCheck, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pCheck, 1, iEnd);
+    if( SQLITE_ROW==sqlite3_step(pCheck) ) bRes = 1;
+    rc = sqlite3_reset(pCheck);
+  }
+  
+  *pbRes = bRes;
+  return rc;
+}
+
+/*
+** This function is called when initializing an incremental-merge operation.
+** It checks if the existing segment with index value iIdx at absolute level 
+** (iAbsLevel+1) can be appended to by the incremental merge. If it can, the
+** merge-writer object *pWriter is initialized to write to it.
+**
+** An existing segment can be appended to by an incremental merge if:
+**
+**   * It was initially created as an appendable segment (with all required
+**     space pre-allocated), and
+**
+**   * The first key read from the input (arguments zKey and nKey) is 
+**     greater than the largest key currently stored in the potential
+**     output segment.
+*/
+static int fts3IncrmergeLoad(
+  Fts3Table *p,                   /* Fts3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of input segments */
+  int iIdx,                       /* Index of candidate output segment */
+  const char *zKey,               /* First key to write */
+  int nKey,                       /* Number of bytes in nKey */
+  IncrmergeWriter *pWriter        /* Populate this object */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pSelect = 0;      /* SELECT to read %_segdir entry */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_int64 iStart = 0;     /* Value of %_segdir.start_block */
+    sqlite3_int64 iLeafEnd = 0;   /* Value of %_segdir.leaves_end_block */
+    sqlite3_int64 iEnd = 0;       /* Value of %_segdir.end_block */
+    const char *aRoot = 0;        /* Pointer to %_segdir.root buffer */
+    int nRoot = 0;                /* Size of aRoot[] in bytes */
+    int rc2;                      /* Return code from sqlite3_reset() */
+    int bAppendable = 0;          /* Set to true if segment is appendable */
+
+    /* Read the %_segdir entry for index iIdx absolute level (iAbsLevel+1) */
+    sqlite3_bind_int64(pSelect, 1, iAbsLevel+1);
+    sqlite3_bind_int(pSelect, 2, iIdx);
+    if( sqlite3_step(pSelect)==SQLITE_ROW ){
+      iStart = sqlite3_column_int64(pSelect, 1);
+      iLeafEnd = sqlite3_column_int64(pSelect, 2);
+      iEnd = sqlite3_column_int64(pSelect, 3);
+      nRoot = sqlite3_column_bytes(pSelect, 4);
+      aRoot = sqlite3_column_blob(pSelect, 4);
+    }else{
+      return sqlite3_reset(pSelect);
+    }
+
+    /* Check for the zero-length marker in the %_segments table */
+    rc = fts3IsAppendable(p, iEnd, &bAppendable);
+
+    /* Check that zKey/nKey is larger than the largest key the candidate */
+    if( rc==SQLITE_OK && bAppendable ){
+      char *aLeaf = 0;
+      int nLeaf = 0;
+
+      rc = sqlite3Fts3ReadBlock(p, iLeafEnd, &aLeaf, &nLeaf, 0);
+      if( rc==SQLITE_OK ){
+        NodeReader reader;
+        for(rc = nodeReaderInit(&reader, aLeaf, nLeaf);
+            rc==SQLITE_OK && reader.aNode;
+            rc = nodeReaderNext(&reader)
+        ){
+          assert( reader.aNode );
+        }
+        if( fts3TermCmp(zKey, nKey, reader.term.a, reader.term.n)<=0 ){
+          bAppendable = 0;
+        }
+        nodeReaderRelease(&reader);
+      }
+      sqlite3_free(aLeaf);
+    }
+
+    if( rc==SQLITE_OK && bAppendable ){
+      /* It is possible to append to this segment. Set up the IncrmergeWriter
+      ** object to do so.  */
+      int i;
+      int nHeight = (int)aRoot[0];
+      NodeWriter *pNode;
+
+      pWriter->nLeafEst = (int)((iEnd - iStart) + 1)/FTS_MAX_APPENDABLE_HEIGHT;
+      pWriter->iStart = iStart;
+      pWriter->iEnd = iEnd;
+      pWriter->iAbsLevel = iAbsLevel;
+      pWriter->iIdx = iIdx;
+
+      for(i=nHeight+1; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
+        pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
+      }
+
+      pNode = &pWriter->aNodeWriter[nHeight];
+      pNode->iBlock = pWriter->iStart + pWriter->nLeafEst*nHeight;
+      blobGrowBuffer(&pNode->block, MAX(nRoot, p->nNodeSize), &rc);
+      if( rc==SQLITE_OK ){
+        memcpy(pNode->block.a, aRoot, nRoot);
+        pNode->block.n = nRoot;
+      }
+
+      for(i=nHeight; i>=0 && rc==SQLITE_OK; i--){
+        NodeReader reader;
+        pNode = &pWriter->aNodeWriter[i];
+
+        rc = nodeReaderInit(&reader, pNode->block.a, pNode->block.n);
+        while( reader.aNode && rc==SQLITE_OK ) rc = nodeReaderNext(&reader);
+        blobGrowBuffer(&pNode->key, reader.term.n, &rc);
+        if( rc==SQLITE_OK ){
+          memcpy(pNode->key.a, reader.term.a, reader.term.n);
+          pNode->key.n = reader.term.n;
+          if( i>0 ){
+            char *aBlock = 0;
+            int nBlock = 0;
+            pNode = &pWriter->aNodeWriter[i-1];
+            pNode->iBlock = reader.iChild;
+            rc = sqlite3Fts3ReadBlock(p, reader.iChild, &aBlock, &nBlock, 0);
+            blobGrowBuffer(&pNode->block, MAX(nBlock, p->nNodeSize), &rc);
+            if( rc==SQLITE_OK ){
+              memcpy(pNode->block.a, aBlock, nBlock);
+              pNode->block.n = nBlock;
+            }
+            sqlite3_free(aBlock);
+          }
+        }
+        nodeReaderRelease(&reader);
+      }
+    }
+
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+/*
+** Determine the largest segment index value that exists within absolute
+** level iAbsLevel+1. If no error occurs, set *piIdx to this value plus
+** one before returning SQLITE_OK. Or, if there are no segments at all 
+** within level iAbsLevel, set *piIdx to zero.
+**
+** If an error occurs, return an SQLite error code. The final value of
+** *piIdx is undefined in this case.
+*/
+static int fts3IncrmergeOutputIdx( 
+  Fts3Table *p,                   /* FTS Table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute index of input segments */
+  int *piIdx                      /* OUT: Next free index at iAbsLevel+1 */
+){
+  int rc;
+  sqlite3_stmt *pOutputIdx = 0;   /* SQL used to find output index */
+
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pOutputIdx, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pOutputIdx, 1, iAbsLevel+1);
+    sqlite3_step(pOutputIdx);
+    *piIdx = sqlite3_column_int(pOutputIdx, 0);
+    rc = sqlite3_reset(pOutputIdx);
+  }
+
+  return rc;
+}
+
+/* 
+** Allocate an appendable output segment on absolute level iAbsLevel+1
+** with idx value iIdx.
+**
+** In the %_segdir table, a segment is defined by the values in three
+** columns:
+**
+**     start_block
+**     leaves_end_block
+**     end_block
+**
+** When an appendable segment is allocated, it is estimated that the
+** maximum number of leaf blocks that may be required is the sum of the
+** number of leaf blocks consumed by the input segments, plus the number
+** of input segments, multiplied by two. This value is stored in stack 
+** variable nLeafEst.
+**
+** A total of 16*nLeafEst blocks are allocated when an appendable segment
+** is created ((1 + end_block - start_block)==16*nLeafEst). The contiguous
+** array of leaf nodes starts at the first block allocated. The array
+** of interior nodes that are parents of the leaf nodes start at block
+** (start_block + (1 + end_block - start_block) / 16). And so on.
+**
+** In the actual code below, the value "16" is replaced with the 
+** pre-processor macro FTS_MAX_APPENDABLE_HEIGHT.
+*/
+static int fts3IncrmergeWriter( 
+  Fts3Table *p,                   /* Fts3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of input segments */
+  int iIdx,                       /* Index of new output segment */
+  Fts3MultiSegReader *pCsr,       /* Cursor that data will be read from */
+  IncrmergeWriter *pWriter        /* Populate this object */
+){
+  int rc;                         /* Return Code */
+  int i;                          /* Iterator variable */
+  int nLeafEst = 0;               /* Blocks allocated for leaf nodes */
+  sqlite3_stmt *pLeafEst = 0;     /* SQL used to determine nLeafEst */
+  sqlite3_stmt *pFirstBlock = 0;  /* SQL used to determine first block */
+
+  /* Calculate nLeafEst. */
+  rc = fts3SqlStmt(p, SQL_MAX_LEAF_NODE_ESTIMATE, &pLeafEst, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pLeafEst, 1, iAbsLevel);
+    sqlite3_bind_int64(pLeafEst, 2, pCsr->nSegment);
+    if( SQLITE_ROW==sqlite3_step(pLeafEst) ){
+      nLeafEst = sqlite3_column_int(pLeafEst, 0);
+    }
+    rc = sqlite3_reset(pLeafEst);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Calculate the first block to use in the output segment */
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pFirstBlock, 0);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pFirstBlock) ){
+      pWriter->iStart = sqlite3_column_int64(pFirstBlock, 0);
+      pWriter->iEnd = pWriter->iStart - 1;
+      pWriter->iEnd += nLeafEst * FTS_MAX_APPENDABLE_HEIGHT;
+    }
+    rc = sqlite3_reset(pFirstBlock);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Insert the marker in the %_segments table to make sure nobody tries
+  ** to steal the space just allocated. This is also used to identify 
+  ** appendable segments.  */
+  rc = fts3WriteSegment(p, pWriter->iEnd, 0, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  pWriter->iAbsLevel = iAbsLevel;
+  pWriter->nLeafEst = nLeafEst;
+  pWriter->iIdx = iIdx;
+
+  /* Set up the array of NodeWriter objects */
+  for(i=0; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
+    pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Remove an entry from the %_segdir table. This involves running the 
+** following two statements:
+**
+**   DELETE FROM %_segdir WHERE level = :iAbsLevel AND idx = :iIdx
+**   UPDATE %_segdir SET idx = idx - 1 WHERE level = :iAbsLevel AND idx > :iIdx
+**
+** The DELETE statement removes the specific %_segdir level. The UPDATE 
+** statement ensures that the remaining segments have contiguously allocated
+** idx values.
+*/
+static int fts3RemoveSegdirEntry(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level to delete from */
+  int iIdx                        /* Index of %_segdir entry to delete */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pDelete = 0;      /* DELETE statement */
+
+  rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_ENTRY, &pDelete, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pDelete, 1, iAbsLevel);
+    sqlite3_bind_int(pDelete, 2, iIdx);
+    sqlite3_step(pDelete);
+    rc = sqlite3_reset(pDelete);
+  }
+
+  return rc;
+}
+
+/*
+** One or more segments have just been removed from absolute level iAbsLevel.
+** Update the 'idx' values of the remaining segments in the level so that
+** the idx values are a contiguous sequence starting from 0.
+*/
+static int fts3RepackSegdirLevel(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel         /* Absolute level to repack */
+){
+  int rc;                         /* Return code */
+  int *aIdx = 0;                  /* Array of remaining idx values */
+  int nIdx = 0;                   /* Valid entries in aIdx[] */
+  int nAlloc = 0;                 /* Allocated size of aIdx[] */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pSelect = 0;      /* Select statement to read idx values */
+  sqlite3_stmt *pUpdate = 0;      /* Update statement to modify idx values */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_INDEXES, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int64(pSelect, 1, iAbsLevel);
+    while( SQLITE_ROW==sqlite3_step(pSelect) ){
+      if( nIdx>=nAlloc ){
+        int *aNew;
+        nAlloc += 16;
+        aNew = sqlite3_realloc(aIdx, nAlloc*sizeof(int));
+        if( !aNew ){
+          rc = SQLITE_NOMEM;
+          break;
+        }
+        aIdx = aNew;
+      }
+      aIdx[nIdx++] = sqlite3_column_int(pSelect, 0);
+    }
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts3SqlStmt(p, SQL_SHIFT_SEGDIR_ENTRY, &pUpdate, 0);
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pUpdate, 2, iAbsLevel);
+  }
+
+  assert( p->bIgnoreSavepoint==0 );
+  p->bIgnoreSavepoint = 1;
+  for(i=0; rc==SQLITE_OK && i<nIdx; i++){
+    if( aIdx[i]!=i ){
+      sqlite3_bind_int(pUpdate, 3, aIdx[i]);
+      sqlite3_bind_int(pUpdate, 1, i);
+      sqlite3_step(pUpdate);
+      rc = sqlite3_reset(pUpdate);
+    }
+  }
+  p->bIgnoreSavepoint = 0;
+
+  sqlite3_free(aIdx);
+  return rc;
+}
+
+static void fts3StartNode(Blob *pNode, int iHeight, sqlite3_int64 iChild){
+  pNode->a[0] = (char)iHeight;
+  if( iChild ){
+    assert( pNode->nAlloc>=1+sqlite3Fts3VarintLen(iChild) );
+    pNode->n = 1 + sqlite3Fts3PutVarint(&pNode->a[1], iChild);
+  }else{
+    assert( pNode->nAlloc>=1 );
+    pNode->n = 1;
+  }
+}
+
+/*
+** The first two arguments are a pointer to and the size of a segment b-tree
+** node. The node may be a leaf or an internal node.
+**
+** This function creates a new node image in blob object *pNew by copying
+** all terms that are greater than or equal to zTerm/nTerm (for leaf nodes)
+** or greater than zTerm/nTerm (for internal nodes) from aNode/nNode.
+*/
+static int fts3TruncateNode(
+  const char *aNode,              /* Current node image */
+  int nNode,                      /* Size of aNode in bytes */
+  Blob *pNew,                     /* OUT: Write new node image here */
+  const char *zTerm,              /* Omit all terms smaller than this */
+  int nTerm,                      /* Size of zTerm in bytes */
+  sqlite3_int64 *piBlock          /* OUT: Block number in next layer down */
+){
+  NodeReader reader;              /* Reader object */
+  Blob prev = {0, 0, 0};          /* Previous term written to new node */
+  int rc = SQLITE_OK;             /* Return code */
+  int bLeaf = aNode[0]=='\0';     /* True for a leaf node */
+
+  /* Allocate required output space */
+  blobGrowBuffer(pNew, nNode, &rc);
+  if( rc!=SQLITE_OK ) return rc;
+  pNew->n = 0;
+
+  /* Populate new node buffer */
+  for(rc = nodeReaderInit(&reader, aNode, nNode); 
+      rc==SQLITE_OK && reader.aNode; 
+      rc = nodeReaderNext(&reader)
+  ){
+    if( pNew->n==0 ){
+      int res = fts3TermCmp(reader.term.a, reader.term.n, zTerm, nTerm);
+      if( res<0 || (bLeaf==0 && res==0) ) continue;
+      fts3StartNode(pNew, (int)aNode[0], reader.iChild);
+      *piBlock = reader.iChild;
+    }
+    rc = fts3AppendToNode(
+        pNew, &prev, reader.term.a, reader.term.n,
+        reader.aDoclist, reader.nDoclist
+    );
+    if( rc!=SQLITE_OK ) break;
+  }
+  if( pNew->n==0 ){
+    fts3StartNode(pNew, (int)aNode[0], reader.iChild);
+    *piBlock = reader.iChild;
+  }
+  assert( pNew->n<=pNew->nAlloc );
+
+  nodeReaderRelease(&reader);
+  sqlite3_free(prev.a);
+  return rc;
+}
+
+/*
+** Remove all terms smaller than zTerm/nTerm from segment iIdx in absolute 
+** level iAbsLevel. This may involve deleting entries from the %_segments
+** table, and modifying existing entries in both the %_segments and %_segdir
+** tables.
+**
+** SQLITE_OK is returned if the segment is updated successfully. Or an
+** SQLite error code otherwise.
+*/
+static int fts3TruncateSegment(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of segment to modify */
+  int iIdx,                       /* Index within level of segment to modify */
+  const char *zTerm,              /* Remove terms smaller than this */
+  int nTerm                      /* Number of bytes in buffer zTerm */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Blob root = {0,0,0};            /* New root page image */
+  Blob block = {0,0,0};           /* Buffer used for any other block */
+  sqlite3_int64 iBlock = 0;       /* Block id */
+  sqlite3_int64 iNewStart = 0;    /* New value for iStartBlock */
+  sqlite3_int64 iOldStart = 0;    /* Old value for iStartBlock */
+  sqlite3_stmt *pFetch = 0;       /* Statement used to fetch segdir */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pFetch, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;                      /* sqlite3_reset() return code */
+    sqlite3_bind_int64(pFetch, 1, iAbsLevel);
+    sqlite3_bind_int(pFetch, 2, iIdx);
+    if( SQLITE_ROW==sqlite3_step(pFetch) ){
+      const char *aRoot = sqlite3_column_blob(pFetch, 4);
+      int nRoot = sqlite3_column_bytes(pFetch, 4);
+      iOldStart = sqlite3_column_int64(pFetch, 1);
+      rc = fts3TruncateNode(aRoot, nRoot, &root, zTerm, nTerm, &iBlock);
+    }
+    rc2 = sqlite3_reset(pFetch);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  while( rc==SQLITE_OK && iBlock ){
+    char *aBlock = 0;
+    int nBlock = 0;
+    iNewStart = iBlock;
+
+    rc = sqlite3Fts3ReadBlock(p, iBlock, &aBlock, &nBlock, 0);
+    if( rc==SQLITE_OK ){
+      rc = fts3TruncateNode(aBlock, nBlock, &block, zTerm, nTerm, &iBlock);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3WriteSegment(p, iNewStart, block.a, block.n);
+    }
+    sqlite3_free(aBlock);
+  }
+
+  /* Variable iNewStart now contains the first valid leaf node. */
+  if( rc==SQLITE_OK && iNewStart ){
+    sqlite3_stmt *pDel = 0;
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDel, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDel, 1, iOldStart);
+      sqlite3_bind_int64(pDel, 2, iNewStart-1);
+      sqlite3_step(pDel);
+      rc = sqlite3_reset(pDel);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3_stmt *pChomp = 0;
+    rc = fts3SqlStmt(p, SQL_CHOMP_SEGDIR, &pChomp, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pChomp, 1, iNewStart);
+      sqlite3_bind_blob(pChomp, 2, root.a, root.n, SQLITE_STATIC);
+      sqlite3_bind_int64(pChomp, 3, iAbsLevel);
+      sqlite3_bind_int(pChomp, 4, iIdx);
+      sqlite3_step(pChomp);
+      rc = sqlite3_reset(pChomp);
+    }
+  }
+
+  sqlite3_free(root.a);
+  sqlite3_free(block.a);
+  return rc;
+}
+
+/*
+** This function is called after an incrmental-merge operation has run to
+** merge (or partially merge) two or more segments from absolute level
+** iAbsLevel.
+**
+** Each input segment is either removed from the db completely (if all of
+** its data was copied to the output segment by the incrmerge operation)
+** or modified in place so that it no longer contains those entries that
+** have been duplicated in the output segment.
+*/
+static int fts3IncrmergeChomp(
+  Fts3Table *p,                   /* FTS table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level containing segments */
+  Fts3MultiSegReader *pCsr,       /* Chomp all segments opened by this cursor */
+  int *pnRem                      /* Number of segments not deleted */
+){
+  int i;
+  int nRem = 0;
+  int rc = SQLITE_OK;
+
+  for(i=pCsr->nSegment-1; i>=0 && rc==SQLITE_OK; i--){
+    Fts3SegReader *pSeg = 0;
+    int j;
+
+    /* Find the Fts3SegReader object with Fts3SegReader.iIdx==i. It is hiding
+    ** somewhere in the pCsr->apSegment[] array.  */
+    for(j=0; ALWAYS(j<pCsr->nSegment); j++){
+      pSeg = pCsr->apSegment[j];
+      if( pSeg->iIdx==i ) break;
+    }
+    assert( j<pCsr->nSegment && pSeg->iIdx==i );
+
+    if( pSeg->aNode==0 ){
+      /* Seg-reader is at EOF. Remove the entire input segment. */
+      rc = fts3DeleteSegment(p, pSeg);
+      if( rc==SQLITE_OK ){
+        rc = fts3RemoveSegdirEntry(p, iAbsLevel, pSeg->iIdx);
+      }
+      *pnRem = 0;
+    }else{
+      /* The incremental merge did not copy all the data from this 
+      ** segment to the upper level. The segment is modified in place
+      ** so that it contains no keys smaller than zTerm/nTerm. */ 
+      const char *zTerm = pSeg->zTerm;
+      int nTerm = pSeg->nTerm;
+      rc = fts3TruncateSegment(p, iAbsLevel, pSeg->iIdx, zTerm, nTerm);
+      nRem++;
+    }
+  }
+
+  if( rc==SQLITE_OK && nRem!=pCsr->nSegment ){
+    rc = fts3RepackSegdirLevel(p, iAbsLevel);
+  }
+
+  *pnRem = nRem;
+  return rc;
+}
+
+/*
+** Store an incr-merge hint in the database.
+*/
+static int fts3IncrmergeHintStore(Fts3Table *p, Blob *pHint){
+  sqlite3_stmt *pReplace = 0;
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pReplace, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pReplace, 1, FTS_STAT_INCRMERGEHINT);
+    sqlite3_bind_blob(pReplace, 2, pHint->a, pHint->n, SQLITE_STATIC);
+    sqlite3_step(pReplace);
+    rc = sqlite3_reset(pReplace);
+  }
+
+  return rc;
+}
+
+/*
+** Load an incr-merge hint from the database. The incr-merge hint, if one 
+** exists, is stored in the rowid==1 row of the %_stat table.
+**
+** If successful, populate blob *pHint with the value read from the %_stat
+** table and return SQLITE_OK. Otherwise, if an error occurs, return an
+** SQLite error code.
+*/
+static int fts3IncrmergeHintLoad(Fts3Table *p, Blob *pHint){
+  sqlite3_stmt *pSelect = 0;
+  int rc;
+
+  pHint->n = 0;
+  rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pSelect, 1, FTS_STAT_INCRMERGEHINT);
+    if( SQLITE_ROW==sqlite3_step(pSelect) ){
+      const char *aHint = sqlite3_column_blob(pSelect, 0);
+      int nHint = sqlite3_column_bytes(pSelect, 0);
+      if( aHint ){
+        blobGrowBuffer(pHint, nHint, &rc);
+        if( rc==SQLITE_OK ){
+          memcpy(pHint->a, aHint, nHint);
+          pHint->n = nHint;
+        }
+      }
+    }
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+/*
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, append an entry to the hint stored in blob *pHint. Each entry
+** consists of two varints, the absolute level number of the input segments 
+** and the number of input segments.
+**
+** If successful, leave *pRc set to SQLITE_OK and return. If an error occurs,
+** set *pRc to an SQLite error code before returning.
+*/
+static void fts3IncrmergeHintPush(
+  Blob *pHint,                    /* Hint blob to append to */
+  i64 iAbsLevel,                  /* First varint to store in hint */
+  int nInput,                     /* Second varint to store in hint */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  blobGrowBuffer(pHint, pHint->n + 2*FTS3_VARINT_MAX, pRc);
+  if( *pRc==SQLITE_OK ){
+    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], iAbsLevel);
+    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], (i64)nInput);
+  }
+}
+
+/*
+** Read the last entry (most recently pushed) from the hint blob *pHint
+** and then remove the entry. Write the two values read to *piAbsLevel and 
+** *pnInput before returning.
+**
+** If no error occurs, return SQLITE_OK. If the hint blob in *pHint does
+** not contain at least two valid varints, return SQLITE_CORRUPT_VTAB.
+*/
+static int fts3IncrmergeHintPop(Blob *pHint, i64 *piAbsLevel, int *pnInput){
+  const int nHint = pHint->n;
+  int i;
+
+  i = pHint->n-2;
+  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
+  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
+
+  pHint->n = i;
+  i += sqlite3Fts3GetVarint(&pHint->a[i], piAbsLevel);
+  i += sqlite3Fts3GetVarint32(&pHint->a[i], pnInput);
+  if( i!=nHint ) return SQLITE_CORRUPT_VTAB;
+
+  return SQLITE_OK;
+}
+
+
+/*
+** Attempt an incremental merge that writes nMerge leaf blocks.
+**
+** Incremental merges happen nMin segments at a time. The two
+** segments to be merged are the nMin oldest segments (the ones with
+** the smallest indexes) in the highest level that contains at least
+** nMin segments. Multiple merges might occur in an attempt to write the 
+** quota of nMerge leaf blocks.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){
+  int rc;                         /* Return code */
+  int nRem = nMerge;              /* Number of leaf pages yet to  be written */
+  Fts3MultiSegReader *pCsr;       /* Cursor used to read input data */
+  Fts3SegFilter *pFilter;         /* Filter used with cursor pCsr */
+  IncrmergeWriter *pWriter;       /* Writer object */
+  int nSeg = 0;                   /* Number of input segments */
+  sqlite3_int64 iAbsLevel = 0;    /* Absolute level number to work on */
+  Blob hint = {0, 0, 0};          /* Hint read from %_stat table */
+  int bDirtyHint = 0;             /* True if blob 'hint' has been modified */
+
+  /* Allocate space for the cursor, filter and writer objects */
+  const int nAlloc = sizeof(*pCsr) + sizeof(*pFilter) + sizeof(*pWriter);
+  pWriter = (IncrmergeWriter *)sqlite3_malloc(nAlloc);
+  if( !pWriter ) return SQLITE_NOMEM;
+  pFilter = (Fts3SegFilter *)&pWriter[1];
+  pCsr = (Fts3MultiSegReader *)&pFilter[1];
+
+  rc = fts3IncrmergeHintLoad(p, &hint);
+  while( rc==SQLITE_OK && nRem>0 ){
+    const i64 nMod = FTS3_SEGDIR_MAXLEVEL * p->nIndex;
+    sqlite3_stmt *pFindLevel = 0; /* SQL used to determine iAbsLevel */
+    int bUseHint = 0;             /* True if attempting to append */
+
+    /* Search the %_segdir table for the absolute level with the smallest
+    ** relative level number that contains at least nMin segments, if any.
+    ** If one is found, set iAbsLevel to the absolute level number and
+    ** nSeg to nMin. If no level with at least nMin segments can be found, 
+    ** set nSeg to -1.
+    */
+    rc = fts3SqlStmt(p, SQL_FIND_MERGE_LEVEL, &pFindLevel, 0);
+    sqlite3_bind_int(pFindLevel, 1, nMin);
+    if( sqlite3_step(pFindLevel)==SQLITE_ROW ){
+      iAbsLevel = sqlite3_column_int64(pFindLevel, 0);
+      nSeg = nMin;
+    }else{
+      nSeg = -1;
+    }
+    rc = sqlite3_reset(pFindLevel);
+
+    /* If the hint read from the %_stat table is not empty, check if the
+    ** last entry in it specifies a relative level smaller than or equal
+    ** to the level identified by the block above (if any). If so, this 
+    ** iteration of the loop will work on merging at the hinted level.
+    */
+    if( rc==SQLITE_OK && hint.n ){
+      int nHint = hint.n;
+      sqlite3_int64 iHintAbsLevel = 0;      /* Hint level */
+      int nHintSeg = 0;                     /* Hint number of segments */
+
+      rc = fts3IncrmergeHintPop(&hint, &iHintAbsLevel, &nHintSeg);
+      if( nSeg<0 || (iAbsLevel % nMod) >= (iHintAbsLevel % nMod) ){
+        iAbsLevel = iHintAbsLevel;
+        nSeg = nHintSeg;
+        bUseHint = 1;
+        bDirtyHint = 1;
+      }else{
+        /* This undoes the effect of the HintPop() above - so that no entry
+        ** is removed from the hint blob.  */
+        hint.n = nHint;
+      }
+    }
+
+    /* If nSeg is less that zero, then there is no level with at least
+    ** nMin segments and no hint in the %_stat table. No work to do.
+    ** Exit early in this case.  */
+    if( nSeg<0 ) break;
+
+    /* Open a cursor to iterate through the contents of the oldest nSeg 
+    ** indexes of absolute level iAbsLevel. If this cursor is opened using 
+    ** the 'hint' parameters, it is possible that there are less than nSeg
+    ** segments available in level iAbsLevel. In this case, no work is
+    ** done on iAbsLevel - fall through to the next iteration of the loop 
+    ** to start work on some other level.  */
+    memset(pWriter, 0, nAlloc);
+    pFilter->flags = FTS3_SEGMENT_REQUIRE_POS;
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergeCsr(p, iAbsLevel, nSeg, pCsr);
+    }
+    if( SQLITE_OK==rc && pCsr->nSegment==nSeg
+     && SQLITE_OK==(rc = sqlite3Fts3SegReaderStart(p, pCsr, pFilter))
+     && SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pCsr))
+    ){
+      int iIdx = 0;               /* Largest idx in level (iAbsLevel+1) */
+      rc = fts3IncrmergeOutputIdx(p, iAbsLevel, &iIdx);
+      if( rc==SQLITE_OK ){
+        if( bUseHint && iIdx>0 ){
+          const char *zKey = pCsr->zTerm;
+          int nKey = pCsr->nTerm;
+          rc = fts3IncrmergeLoad(p, iAbsLevel, iIdx-1, zKey, nKey, pWriter);
+        }else{
+          rc = fts3IncrmergeWriter(p, iAbsLevel, iIdx, pCsr, pWriter);
+        }
+      }
+
+      if( rc==SQLITE_OK && pWriter->nLeafEst ){
+        fts3LogMerge(nSeg, iAbsLevel);
+        do {
+          rc = fts3IncrmergeAppend(p, pWriter, pCsr);
+          if( rc==SQLITE_OK ) rc = sqlite3Fts3SegReaderStep(p, pCsr);
+          if( pWriter->nWork>=nRem && rc==SQLITE_ROW ) rc = SQLITE_OK;
+        }while( rc==SQLITE_ROW );
+
+        /* Update or delete the input segments */
+        if( rc==SQLITE_OK ){
+          nRem -= (1 + pWriter->nWork);
+          rc = fts3IncrmergeChomp(p, iAbsLevel, pCsr, &nSeg);
+          if( nSeg!=0 ){
+            bDirtyHint = 1;
+            fts3IncrmergeHintPush(&hint, iAbsLevel, nSeg, &rc);
+          }
+        }
+      }
+
+      fts3IncrmergeRelease(p, pWriter, &rc);
+    }
+
+    sqlite3Fts3SegReaderFinish(pCsr);
+  }
+
+  /* Write the hint values into the %_stat table for the next incr-merger */
+  if( bDirtyHint && rc==SQLITE_OK ){
+    rc = fts3IncrmergeHintStore(p, &hint);
+  }
+
+  sqlite3_free(pWriter);
+  sqlite3_free(hint.a);
+  return rc;
+}
+
+/*
+** Convert the text beginning at *pz into an integer and return
+** its value.  Advance *pz to point to the first character past
+** the integer.
+*/
+static int fts3Getint(const char **pz){
+  const char *z = *pz;
+  int i = 0;
+  while( (*z)>='0' && (*z)<='9' ) i = 10*i + *(z++) - '0';
+  *pz = z;
+  return i;
+}
+
+/*
+** Process statements of the form:
+**
+**    INSERT INTO table(table) VALUES('merge=A,B');
+**
+** A and B are integers that decode to be the number of leaf pages
+** written for the merge, and the minimum number of segments on a level
+** before it will be selected for a merge, respectively.
+*/
+static int fts3DoIncrmerge(
+  Fts3Table *p,                   /* FTS3 table handle */
+  const char *zParam              /* Nul-terminated string containing "A,B" */
+){
+  int rc;
+  int nMin = (FTS3_MERGE_COUNT / 2);
+  int nMerge = 0;
+  const char *z = zParam;
+
+  /* Read the first integer value */
+  nMerge = fts3Getint(&z);
+
+  /* If the first integer value is followed by a ',',  read the second
+  ** integer value. */
+  if( z[0]==',' && z[1]!='\0' ){
+    z++;
+    nMin = fts3Getint(&z);
+  }
+
+  if( z[0]!='\0' || nMin<2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    rc = SQLITE_OK;
+    if( !p->bHasStat ){
+      assert( p->bFts4==0 );
+      sqlite3Fts3CreateStatTable(&rc, p);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3Incrmerge(p, nMerge, nMin);
+    }
+    sqlite3Fts3SegmentsClose(p);
+  }
+  return rc;
+}
+
+/*
+** Process statements of the form:
+**
+**    INSERT INTO table(table) VALUES('automerge=X');
+**
+** where X is an integer.  X==0 means to turn automerge off.  X!=0 means
+** turn it on.  The setting is persistent.
+*/
+static int fts3DoAutoincrmerge(
+  Fts3Table *p,                   /* FTS3 table handle */
+  const char *zParam              /* Nul-terminated string containing boolean */
+){
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt = 0;
+  p->bAutoincrmerge = fts3Getint(&zParam)!=0;
+  if( !p->bHasStat ){
+    assert( p->bFts4==0 );
+    sqlite3Fts3CreateStatTable(&rc, p);
+    if( rc ) return rc;
+  }
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
+  if( rc ) return rc;;
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
+  sqlite3_bind_int(pStmt, 2, p->bAutoincrmerge);
+  sqlite3_step(pStmt);
+  rc = sqlite3_reset(pStmt);
+  return rc;
+}
+
+/*
+** Return a 64-bit checksum for the FTS index entry specified by the
+** arguments to this function.
+*/
+static u64 fts3ChecksumEntry(
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int iLangid,                    /* Language id for current row */
+  int iIndex,                     /* Index (0..Fts3Table.nIndex-1) */
+  i64 iDocid,                     /* Docid for current row. */
+  int iCol,                       /* Column number */
+  int iPos                        /* Position */
+){
+  int i;
+  u64 ret = (u64)iDocid;
+
+  ret += (ret<<3) + iLangid;
+  ret += (ret<<3) + iIndex;
+  ret += (ret<<3) + iCol;
+  ret += (ret<<3) + iPos;
+  for(i=0; i<nTerm; i++) ret += (ret<<3) + zTerm[i];
+
+  return ret;
+}
+
+/*
+** Return a checksum of all entries in the FTS index that correspond to
+** language id iLangid. The checksum is calculated by XORing the checksums
+** of each individual entry (see fts3ChecksumEntry()) together.
+**
+** If successful, the checksum value is returned and *pRc set to SQLITE_OK.
+** Otherwise, if an error occurs, *pRc is set to an SQLite error code. The
+** return value is undefined in this case.
+*/
+static u64 fts3ChecksumIndex(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id to return cksum for */
+  int iIndex,                     /* Index to cksum (0..p->nIndex-1) */
+  int *pRc                        /* OUT: Return code */
+){
+  Fts3SegFilter filter;
+  Fts3MultiSegReader csr;
+  int rc;
+  u64 cksum = 0;
+
+  assert( *pRc==SQLITE_OK );
+
+  memset(&filter, 0, sizeof(filter));
+  memset(&csr, 0, sizeof(csr));
+  filter.flags =  FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+  filter.flags |= FTS3_SEGMENT_SCAN;
+
+  rc = sqlite3Fts3SegReaderCursor(
+      p, iLangid, iIndex, FTS3_SEGCURSOR_ALL, 0, 0, 0, 1,&csr
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
+  }
+
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, &csr)) ){
+      char *pCsr = csr.aDoclist;
+      char *pEnd = &pCsr[csr.nDoclist];
+
+      i64 iDocid = 0;
+      i64 iCol = 0;
+      i64 iPos = 0;
+
+      pCsr += sqlite3Fts3GetVarint(pCsr, &iDocid);
+      while( pCsr<pEnd ){
+        i64 iVal = 0;
+        pCsr += sqlite3Fts3GetVarint(pCsr, &iVal);
+        if( pCsr<pEnd ){
+          if( iVal==0 || iVal==1 ){
+            iCol = 0;
+            iPos = 0;
+            if( iVal ){
+              pCsr += sqlite3Fts3GetVarint(pCsr, &iCol);
+            }else{
+              pCsr += sqlite3Fts3GetVarint(pCsr, &iVal);
+              iDocid += iVal;
+            }
+          }else{
+            iPos += (iVal - 2);
+            cksum = cksum ^ fts3ChecksumEntry(
+                csr.zTerm, csr.nTerm, iLangid, iIndex, iDocid,
+                (int)iCol, (int)iPos
+            );
+          }
+        }
+      }
+    }
+  }
+  sqlite3Fts3SegReaderFinish(&csr);
+
+  *pRc = rc;
+  return cksum;
+}
+
+/*
+** Check if the contents of the FTS index match the current contents of the
+** content table. If no error occurs and the contents do match, set *pbOk
+** to true and return SQLITE_OK. Or if the contents do not match, set *pbOk
+** to false before returning.
+**
+** If an error occurs (e.g. an OOM or IO error), return an SQLite error 
+** code. The final value of *pbOk is undefined in this case.
+*/
+static int fts3IntegrityCheck(Fts3Table *p, int *pbOk){
+  int rc = SQLITE_OK;             /* Return code */
+  u64 cksum1 = 0;                 /* Checksum based on FTS index contents */
+  u64 cksum2 = 0;                 /* Checksum based on %_content contents */
+  sqlite3_stmt *pAllLangid = 0;   /* Statement to return all language-ids */
+
+  /* This block calculates the checksum according to the FTS index. */
+  rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pAllLangid, 1, p->nIndex);
+    while( rc==SQLITE_OK && sqlite3_step(pAllLangid)==SQLITE_ROW ){
+      int iLangid = sqlite3_column_int(pAllLangid, 0);
+      int i;
+      for(i=0; i<p->nIndex; i++){
+        cksum1 = cksum1 ^ fts3ChecksumIndex(p, iLangid, i, &rc);
+      }
+    }
+    rc2 = sqlite3_reset(pAllLangid);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  /* This block calculates the checksum according to the %_content table */
+  rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_tokenizer_module const *pModule = p->pTokenizer->pModule;
+    sqlite3_stmt *pStmt = 0;
+    char *zSql;
+   
+    zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
+      sqlite3_free(zSql);
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      i64 iDocid = sqlite3_column_int64(pStmt, 0);
+      int iLang = langidFromSelect(p, pStmt);
+      int iCol;
+
+      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
+        const char *zText = (const char *)sqlite3_column_text(pStmt, iCol+1);
+        int nText = sqlite3_column_bytes(pStmt, iCol+1);
+        sqlite3_tokenizer_cursor *pT = 0;
+
+        rc = sqlite3Fts3OpenTokenizer(p->pTokenizer, iLang, zText, nText, &pT);
+        while( rc==SQLITE_OK ){
+          char const *zToken;       /* Buffer containing token */
+          int nToken;               /* Number of bytes in token */
+          int iDum1, iDum2;         /* Dummy variables */
+          int iPos;                 /* Position of token in zText */
+
+          rc = pModule->xNext(pT, &zToken, &nToken, &iDum1, &iDum2, &iPos);
+          if( rc==SQLITE_OK ){
+            int i;
+            cksum2 = cksum2 ^ fts3ChecksumEntry(
+                zToken, nToken, iLang, 0, iDocid, iCol, iPos
+            );
+            for(i=1; i<p->nIndex; i++){
+              if( p->aIndex[i].nPrefix<=nToken ){
+                cksum2 = cksum2 ^ fts3ChecksumEntry(
+                  zToken, p->aIndex[i].nPrefix, iLang, i, iDocid, iCol, iPos
+                );
+              }
+            }
+          }
+        }
+        if( pT ) pModule->xClose(pT);
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+      }
+    }
+
+    sqlite3_finalize(pStmt);
+  }
+
+  *pbOk = (cksum1==cksum2);
+  return rc;
+}
+
+/*
+** Run the integrity-check. If no error occurs and the current contents of
+** the FTS index are correct, return SQLITE_OK. Or, if the contents of the
+** FTS index are incorrect, return SQLITE_CORRUPT_VTAB.
+**
+** Or, if an error (e.g. an OOM or IO error) occurs, return an SQLite 
+** error code.
+**
+** The integrity-check works as follows. For each token and indexed token
+** prefix in the document set, a 64-bit checksum is calculated (by code
+** in fts3ChecksumEntry()) based on the following:
+**
+**     + The index number (0 for the main index, 1 for the first prefix
+**       index etc.),
+**     + The token (or token prefix) text itself, 
+**     + The language-id of the row it appears in,
+**     + The docid of the row it appears in,
+**     + The column it appears in, and
+**     + The tokens position within that column.
+**
+** The checksums for all entries in the index are XORed together to create
+** a single checksum for the entire index.
+**
+** The integrity-check code calculates the same checksum in two ways:
+**
+**     1. By scanning the contents of the FTS index, and 
+**     2. By scanning and tokenizing the content table.
+**
+** If the two checksums are identical, the integrity-check is deemed to have
+** passed.
+*/
+static int fts3DoIntegrityCheck(
+  Fts3Table *p                    /* FTS3 table handle */
+){
+  int rc;
+  int bOk = 0;
+  rc = fts3IntegrityCheck(p, &bOk);
+  if( rc==SQLITE_OK && bOk==0 ) rc = SQLITE_CORRUPT_VTAB;
+  return rc;
+}
+
+/*
+** Handle a 'special' INSERT of the form:
+**
+**   "INSERT INTO tbl(tbl) VALUES(<expr>)"
+**
+** Argument pVal contains the result of <expr>. Currently the only 
+** meaningful value to insert is the text 'optimize'.
+*/
+static int fts3SpecialInsert(Fts3Table *p, sqlite3_value *pVal){
+  int rc;                         /* Return Code */
+  const char *zVal = (const char *)sqlite3_value_text(pVal);
+  int nVal = sqlite3_value_bytes(pVal);
+
+  if( !zVal ){
+    return SQLITE_NOMEM;
+  }else if( nVal==8 && 0==sqlite3_strnicmp(zVal, "optimize", 8) ){
+    rc = fts3DoOptimize(p, 0);
+  }else if( nVal==7 && 0==sqlite3_strnicmp(zVal, "rebuild", 7) ){
+    rc = fts3DoRebuild(p);
+  }else if( nVal==15 && 0==sqlite3_strnicmp(zVal, "integrity-check", 15) ){
+    rc = fts3DoIntegrityCheck(p);
+  }else if( nVal>6 && 0==sqlite3_strnicmp(zVal, "merge=", 6) ){
+    rc = fts3DoIncrmerge(p, &zVal[6]);
+  }else if( nVal>10 && 0==sqlite3_strnicmp(zVal, "automerge=", 10) ){
+    rc = fts3DoAutoincrmerge(p, &zVal[10]);
+#ifdef SQLITE_TEST
+  }else if( nVal>9 && 0==sqlite3_strnicmp(zVal, "nodesize=", 9) ){
+    p->nNodeSize = atoi(&zVal[9]);
+    rc = SQLITE_OK;
+  }else if( nVal>11 && 0==sqlite3_strnicmp(zVal, "maxpending=", 9) ){
+    p->nMaxPendingData = atoi(&zVal[11]);
+    rc = SQLITE_OK;
+#endif
+  }else{
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+/*
+** Delete all cached deferred doclists. Deferred doclists are cached
+** (allocated) by the sqlite3Fts3CacheDeferredDoclists() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *pCsr){
+  Fts3DeferredToken *pDef;
+  for(pDef=pCsr->pDeferred; pDef; pDef=pDef->pNext){
+    fts3PendingListDelete(pDef->pList);
+    pDef->pList = 0;
+  }
+}
+
+/*
+** Free all entries in the pCsr->pDeffered list. Entries are added to 
+** this list using sqlite3Fts3DeferToken().
+*/
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *pCsr){
+  Fts3DeferredToken *pDef;
+  Fts3DeferredToken *pNext;
+  for(pDef=pCsr->pDeferred; pDef; pDef=pNext){
+    pNext = pDef->pNext;
+    fts3PendingListDelete(pDef->pList);
+    sqlite3_free(pDef);
+  }
+  pCsr->pDeferred = 0;
+}
+
+/*
+** Generate deferred-doclists for all tokens in the pCsr->pDeferred list
+** based on the row that pCsr currently points to.
+**
+** A deferred-doclist is like any other doclist with position information
+** included, except that it only contains entries for a single row of the
+** table, not for all rows.
+*/
+SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;             /* Return code */
+  if( pCsr->pDeferred ){
+    int i;                        /* Used to iterate through table columns */
+    sqlite3_int64 iDocid;         /* Docid of the row pCsr points to */
+    Fts3DeferredToken *pDef;      /* Used to iterate through deferred tokens */
+  
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    sqlite3_tokenizer *pT = p->pTokenizer;
+    sqlite3_tokenizer_module const *pModule = pT->pModule;
+   
+    assert( pCsr->isRequireSeek==0 );
+    iDocid = sqlite3_column_int64(pCsr->pStmt, 0);
+  
+    for(i=0; i<p->nColumn && rc==SQLITE_OK; i++){
+      const char *zText = (const char *)sqlite3_column_text(pCsr->pStmt, i+1);
+      sqlite3_tokenizer_cursor *pTC = 0;
+  
+      rc = sqlite3Fts3OpenTokenizer(pT, pCsr->iLangid, zText, -1, &pTC);
+      while( rc==SQLITE_OK ){
+        char const *zToken;       /* Buffer containing token */
+        int nToken;               /* Number of bytes in token */
+        int iDum1, iDum2;         /* Dummy variables */
+        int iPos;                 /* Position of token in zText */
+  
+        rc = pModule->xNext(pTC, &zToken, &nToken, &iDum1, &iDum2, &iPos);
+        for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
+          Fts3PhraseToken *pPT = pDef->pToken;
+          if( (pDef->iCol>=p->nColumn || pDef->iCol==i)
+           && (pPT->bFirst==0 || iPos==0)
+           && (pPT->n==nToken || (pPT->isPrefix && pPT->n<nToken))
+           && (0==memcmp(zToken, pPT->z, pPT->n))
+          ){
+            fts3PendingListAppend(&pDef->pList, iDocid, i, iPos, &rc);
+          }
+        }
+      }
+      if( pTC ) pModule->xClose(pTC);
+      if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+    }
+  
+    for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
+      if( pDef->pList ){
+        rc = fts3PendingListAppendVarint(&pDef->pList, 0);
+      }
+    }
+  }
+
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(
+  Fts3DeferredToken *p, 
+  char **ppData, 
+  int *pnData
+){
+  char *pRet;
+  int nSkip;
+  sqlite3_int64 dummy;
+
+  *ppData = 0;
+  *pnData = 0;
+
+  if( p->pList==0 ){
+    return SQLITE_OK;
+  }
+
+  pRet = (char *)sqlite3_malloc(p->pList->nData);
+  if( !pRet ) return SQLITE_NOMEM;
+
+  nSkip = sqlite3Fts3GetVarint(p->pList->aData, &dummy);
+  *pnData = p->pList->nData - nSkip;
+  *ppData = pRet;
+  
+  memcpy(pRet, &p->pList->aData[nSkip], *pnData);
+  return SQLITE_OK;
+}
+
+/*
+** Add an entry for token pToken to the pCsr->pDeferred list.
+*/
+SQLITE_PRIVATE int sqlite3Fts3DeferToken(
+  Fts3Cursor *pCsr,               /* Fts3 table cursor */
+  Fts3PhraseToken *pToken,        /* Token to defer */
+  int iCol                        /* Column that token must appear in (or -1) */
+){
+  Fts3DeferredToken *pDeferred;
+  pDeferred = sqlite3_malloc(sizeof(*pDeferred));
+  if( !pDeferred ){
+    return SQLITE_NOMEM;
+  }
+  memset(pDeferred, 0, sizeof(*pDeferred));
+  pDeferred->pToken = pToken;
+  pDeferred->pNext = pCsr->pDeferred; 
+  pDeferred->iCol = iCol;
+  pCsr->pDeferred = pDeferred;
+
+  assert( pToken->pDeferred==0 );
+  pToken->pDeferred = pDeferred;
+
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** SQLite value pRowid contains the rowid of a row that may or may not be
+** present in the FTS3 table. If it is, delete it and adjust the contents
+** of subsiduary data structures accordingly.
+*/
+static int fts3DeleteByRowid(
+  Fts3Table *p, 
+  sqlite3_value *pRowid, 
+  int *pnDoc,
+  u32 *aSzDel
+){
+  int isEmpty = 0;
+  int rc = fts3IsEmpty(p, pRowid, &isEmpty);
+  if( rc==SQLITE_OK ){
+    if( isEmpty ){
+      /* Deleting this row means the whole table is empty. In this case
+      ** delete the contents of all three tables and throw away any
+      ** data in the pendingTerms hash table.  */
+      rc = fts3DeleteAll(p, 1);
+      *pnDoc = *pnDoc - 1;
+    }else{
+      fts3DeleteTerms(&rc, p, pRowid, aSzDel);
+      if( p->zContentTbl==0 ){
+        fts3SqlExec(&rc, p, SQL_DELETE_CONTENT, &pRowid);
+        if( sqlite3_changes(p->db) ) *pnDoc = *pnDoc - 1;
+      }else{
+        *pnDoc = *pnDoc - 1;
+      }
+      if( p->bHasDocsize ){
+        fts3SqlExec(&rc, p, SQL_DELETE_DOCSIZE, &pRowid);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function does the work for the xUpdate method of FTS3 virtual
+** tables. The schema of the virtual table being:
+**
+**     CREATE TABLE <table name>( 
+**       <user columns>,
+**       <table name> HIDDEN, 
+**       docid HIDDEN, 
+**       <langid> HIDDEN
+**     );
+**
+** 
+*/
+SQLITE_PRIVATE int sqlite3Fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* FTS3 vtab object */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_OK;             /* Return Code */
+  int isRemove = 0;               /* True for an UPDATE or DELETE */
+  u32 *aSzIns = 0;                /* Sizes of inserted documents */
+  u32 *aSzDel;                    /* Sizes of deleted documents */
+  int nChng = 0;                  /* Net change in number of documents */
+  int bInsertDone = 0;
+
+  assert( p->pSegments==0 );
+  assert( 
+      nArg==1                     /* DELETE operations */
+   || nArg==(2 + p->nColumn + 3)  /* INSERT or UPDATE operations */
+  );
+
+  /* Check for a "special" INSERT operation. One of the form:
+  **
+  **   INSERT INTO xyz(xyz) VALUES('command');
+  */
+  if( nArg>1 
+   && sqlite3_value_type(apVal[0])==SQLITE_NULL 
+   && sqlite3_value_type(apVal[p->nColumn+2])!=SQLITE_NULL 
+  ){
+    rc = fts3SpecialInsert(p, apVal[p->nColumn+2]);
+    goto update_out;
+  }
+
+  if( nArg>1 && sqlite3_value_int(apVal[2 + p->nColumn + 2])<0 ){
+    rc = SQLITE_CONSTRAINT;
+    goto update_out;
+  }
+
+  /* Allocate space to hold the change in document sizes */
+  aSzIns = sqlite3_malloc( sizeof(aSzIns[0])*(p->nColumn+1)*2 );
+  if( aSzIns==0 ){
+    rc = SQLITE_NOMEM;
+    goto update_out;
+  }
+  aSzDel = &aSzIns[p->nColumn+1];
+  memset(aSzIns, 0, sizeof(aSzIns[0])*(p->nColumn+1)*2);
+
+  /* If this is an INSERT operation, or an UPDATE that modifies the rowid
+  ** value, then this operation requires constraint handling.
+  **
+  ** If the on-conflict mode is REPLACE, this means that the existing row
+  ** should be deleted from the database before inserting the new row. Or,
+  ** if the on-conflict mode is other than REPLACE, then this method must
+  ** detect the conflict and return SQLITE_CONSTRAINT before beginning to
+  ** modify the database file.
+  */
+  if( nArg>1 && p->zContentTbl==0 ){
+    /* Find the value object that holds the new rowid value. */
+    sqlite3_value *pNewRowid = apVal[3+p->nColumn];
+    if( sqlite3_value_type(pNewRowid)==SQLITE_NULL ){
+      pNewRowid = apVal[1];
+    }
+
+    if( sqlite3_value_type(pNewRowid)!=SQLITE_NULL && ( 
+        sqlite3_value_type(apVal[0])==SQLITE_NULL
+     || sqlite3_value_int64(apVal[0])!=sqlite3_value_int64(pNewRowid)
+    )){
+      /* The new rowid is not NULL (in this case the rowid will be
+      ** automatically assigned and there is no chance of a conflict), and 
+      ** the statement is either an INSERT or an UPDATE that modifies the
+      ** rowid column. So if the conflict mode is REPLACE, then delete any
+      ** existing row with rowid=pNewRowid. 
+      **
+      ** Or, if the conflict mode is not REPLACE, insert the new record into 
+      ** the %_content table. If we hit the duplicate rowid constraint (or any
+      ** other error) while doing so, return immediately.
+      **
+      ** This branch may also run if pNewRowid contains a value that cannot
+      ** be losslessly converted to an integer. In this case, the eventual 
+      ** call to fts3InsertData() (either just below or further on in this
+      ** function) will return SQLITE_MISMATCH. If fts3DeleteByRowid is 
+      ** invoked, it will delete zero rows (since no row will have
+      ** docid=$pNewRowid if $pNewRowid is not an integer value).
+      */
+      if( sqlite3_vtab_on_conflict(p->db)==SQLITE_REPLACE ){
+        rc = fts3DeleteByRowid(p, pNewRowid, &nChng, aSzDel);
+      }else{
+        rc = fts3InsertData(p, apVal, pRowid);
+        bInsertDone = 1;
+      }
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    goto update_out;
+  }
+
+  /* If this is a DELETE or UPDATE operation, remove the old record. */
+  if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
+    assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER );
+    rc = fts3DeleteByRowid(p, apVal[0], &nChng, aSzDel);
+    isRemove = 1;
+  }
+  
+  /* If this is an INSERT or UPDATE operation, insert the new record. */
+  if( nArg>1 && rc==SQLITE_OK ){
+    int iLangid = sqlite3_value_int(apVal[2 + p->nColumn + 2]);
+    if( bInsertDone==0 ){
+      rc = fts3InsertData(p, apVal, pRowid);
+      if( rc==SQLITE_CONSTRAINT && p->zContentTbl==0 ){
+        rc = FTS_CORRUPT_VTAB;
+      }
+    }
+    if( rc==SQLITE_OK && (!isRemove || *pRowid!=p->iPrevDocid ) ){
+      rc = fts3PendingTermsDocid(p, iLangid, *pRowid);
+    }
+    if( rc==SQLITE_OK ){
+      assert( p->iPrevDocid==*pRowid );
+      rc = fts3InsertTerms(p, iLangid, apVal, aSzIns);
+    }
+    if( p->bHasDocsize ){
+      fts3InsertDocsize(&rc, p, aSzIns);
+    }
+    nChng++;
+  }
+
+  if( p->bFts4 ){
+    fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nChng);
+  }
+
+ update_out:
+  sqlite3_free(aSzIns);
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+/* 
+** Flush any data in the pending-terms hash table to disk. If successful,
+** merge all segments in the database (including the new segment, if 
+** there was any data to flush) into a single segment. 
+*/
+SQLITE_PRIVATE int sqlite3Fts3Optimize(Fts3Table *p){
+  int rc;
+  rc = sqlite3_exec(p->db, "SAVEPOINT fts3", 0, 0, 0);
+  if( rc==SQLITE_OK ){
+    rc = fts3DoOptimize(p, 1);
+    if( rc==SQLITE_OK || rc==SQLITE_DONE ){
+      int rc2 = sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
+      if( rc2!=SQLITE_OK ) rc = rc2;
+    }else{
+      sqlite3_exec(p->db, "ROLLBACK TO fts3", 0, 0, 0);
+      sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
+    }
+  }
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+#endif
+
+/************** End of fts3_write.c ******************************************/
+/************** Begin file fts3_snippet.c ************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+/*
+** Characters that may appear in the second argument to matchinfo().
+*/
+#define FTS3_MATCHINFO_NPHRASE   'p'        /* 1 value */
+#define FTS3_MATCHINFO_NCOL      'c'        /* 1 value */
+#define FTS3_MATCHINFO_NDOC      'n'        /* 1 value */
+#define FTS3_MATCHINFO_AVGLENGTH 'a'        /* nCol values */
+#define FTS3_MATCHINFO_LENGTH    'l'        /* nCol values */
+#define FTS3_MATCHINFO_LCS       's'        /* nCol values */
+#define FTS3_MATCHINFO_HITS      'x'        /* 3*nCol*nPhrase values */
+
+/*
+** The default value for the second argument to matchinfo(). 
+*/
+#define FTS3_MATCHINFO_DEFAULT   "pcx"
+
+
+/*
+** Used as an fts3ExprIterate() context when loading phrase doclists to
+** Fts3Expr.aDoclist[]/nDoclist.
+*/
+typedef struct LoadDoclistCtx LoadDoclistCtx;
+struct LoadDoclistCtx {
+  Fts3Cursor *pCsr;               /* FTS3 Cursor */
+  int nPhrase;                    /* Number of phrases seen so far */
+  int nToken;                     /* Number of tokens seen so far */
+};
+
+/*
+** The following types are used as part of the implementation of the 
+** fts3BestSnippet() routine.
+*/
+typedef struct SnippetIter SnippetIter;
+typedef struct SnippetPhrase SnippetPhrase;
+typedef struct SnippetFragment SnippetFragment;
+
+struct SnippetIter {
+  Fts3Cursor *pCsr;               /* Cursor snippet is being generated from */
+  int iCol;                       /* Extract snippet from this column */
+  int nSnippet;                   /* Requested snippet length (in tokens) */
+  int nPhrase;                    /* Number of phrases in query */
+  SnippetPhrase *aPhrase;         /* Array of size nPhrase */
+  int iCurrent;                   /* First token of current snippet */
+};
+
+struct SnippetPhrase {
+  int nToken;                     /* Number of tokens in phrase */
+  char *pList;                    /* Pointer to start of phrase position list */
+  int iHead;                      /* Next value in position list */
+  char *pHead;                    /* Position list data following iHead */
+  int iTail;                      /* Next value in trailing position list */
+  char *pTail;                    /* Position list data following iTail */
+};
+
+struct SnippetFragment {
+  int iCol;                       /* Column snippet is extracted from */
+  int iPos;                       /* Index of first token in snippet */
+  u64 covered;                    /* Mask of query phrases covered */
+  u64 hlmask;                     /* Mask of snippet terms to highlight */
+};
+
+/*
+** This type is used as an fts3ExprIterate() context object while 
+** accumulating the data returned by the matchinfo() function.
+*/
+typedef struct MatchInfo MatchInfo;
+struct MatchInfo {
+  Fts3Cursor *pCursor;            /* FTS3 Cursor */
+  int nCol;                       /* Number of columns in table */
+  int nPhrase;                    /* Number of matchable phrases in query */
+  sqlite3_int64 nDoc;             /* Number of docs in database */
+  u32 *aMatchinfo;                /* Pre-allocated buffer */
+};
+
+
+
+/*
+** The snippet() and offsets() functions both return text values. An instance
+** of the following structure is used to accumulate those values while the
+** functions are running. See fts3StringAppend() for details.
+*/
+typedef struct StrBuffer StrBuffer;
+struct StrBuffer {
+  char *z;                        /* Pointer to buffer containing string */
+  int n;                          /* Length of z in bytes (excl. nul-term) */
+  int nAlloc;                     /* Allocated size of buffer z in bytes */
+};
+
+
+/*
+** This function is used to help iterate through a position-list. A position
+** list is a list of unique integers, sorted from smallest to largest. Each
+** element of the list is represented by an FTS3 varint that takes the value
+** of the difference between the current element and the previous one plus
+** two. For example, to store the position-list:
+**
+**     4 9 113
+**
+** the three varints:
+**
+**     6 7 106
+**
+** are encoded.
+**
+** When this function is called, *pp points to the start of an element of
+** the list. *piPos contains the value of the previous entry in the list.
+** After it returns, *piPos contains the value of the next element of the
+** list and *pp is advanced to the following varint.
+*/
+static void fts3GetDeltaPosition(char **pp, int *piPos){
+  int iVal;
+  *pp += sqlite3Fts3GetVarint32(*pp, &iVal);
+  *piPos += (iVal-2);
+}
+
+/*
+** Helper function for fts3ExprIterate() (see below).
+*/
+static int fts3ExprIterate2(
+  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
+  int *piPhrase,                  /* Pointer to phrase counter */
+  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
+  void *pCtx                      /* Second argument to pass to callback */
+){
+  int rc;                         /* Return code */
+  int eType = pExpr->eType;       /* Type of expression node pExpr */
+
+  if( eType!=FTSQUERY_PHRASE ){
+    assert( pExpr->pLeft && pExpr->pRight );
+    rc = fts3ExprIterate2(pExpr->pLeft, piPhrase, x, pCtx);
+    if( rc==SQLITE_OK && eType!=FTSQUERY_NOT ){
+      rc = fts3ExprIterate2(pExpr->pRight, piPhrase, x, pCtx);
+    }
+  }else{
+    rc = x(pExpr, *piPhrase, pCtx);
+    (*piPhrase)++;
+  }
+  return rc;
+}
+
+/*
+** Iterate through all phrase nodes in an FTS3 query, except those that
+** are part of a sub-tree that is the right-hand-side of a NOT operator.
+** For each phrase node found, the supplied callback function is invoked.
+**
+** If the callback function returns anything other than SQLITE_OK, 
+** the iteration is abandoned and the error code returned immediately.
+** Otherwise, SQLITE_OK is returned after a callback has been made for
+** all eligible phrase nodes.
+*/
+static int fts3ExprIterate(
+  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
+  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
+  void *pCtx                      /* Second argument to pass to callback */
+){
+  int iPhrase = 0;                /* Variable used as the phrase counter */
+  return fts3ExprIterate2(pExpr, &iPhrase, x, pCtx);
+}
+
+/*
+** This is an fts3ExprIterate() callback used while loading the doclists
+** for each phrase into Fts3Expr.aDoclist[]/nDoclist. See also
+** fts3ExprLoadDoclists().
+*/
+static int fts3ExprLoadDoclistsCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  int rc = SQLITE_OK;
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;
+
+  UNUSED_PARAMETER(iPhrase);
+
+  p->nPhrase++;
+  p->nToken += pPhrase->nToken;
+
+  return rc;
+}
+
+/*
+** Load the doclists for each phrase in the query associated with FTS3 cursor
+** pCsr. 
+**
+** If pnPhrase is not NULL, then *pnPhrase is set to the number of matchable 
+** phrases in the expression (all phrases except those directly or 
+** indirectly descended from the right-hand-side of a NOT operator). If 
+** pnToken is not NULL, then it is set to the number of tokens in all
+** matchable phrases of the expression.
+*/
+static int fts3ExprLoadDoclists(
+  Fts3Cursor *pCsr,               /* Fts3 cursor for current query */
+  int *pnPhrase,                  /* OUT: Number of phrases in query */
+  int *pnToken                    /* OUT: Number of tokens in query */
+){
+  int rc;                         /* Return Code */
+  LoadDoclistCtx sCtx = {0,0,0};  /* Context for fts3ExprIterate() */
+  sCtx.pCsr = pCsr;
+  rc = fts3ExprIterate(pCsr->pExpr, fts3ExprLoadDoclistsCb, (void *)&sCtx);
+  if( pnPhrase ) *pnPhrase = sCtx.nPhrase;
+  if( pnToken ) *pnToken = sCtx.nToken;
+  return rc;
+}
+
+static int fts3ExprPhraseCountCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  (*(int *)ctx)++;
+  UNUSED_PARAMETER(pExpr);
+  UNUSED_PARAMETER(iPhrase);
+  return SQLITE_OK;
+}
+static int fts3ExprPhraseCount(Fts3Expr *pExpr){
+  int nPhrase = 0;
+  (void)fts3ExprIterate(pExpr, fts3ExprPhraseCountCb, (void *)&nPhrase);
+  return nPhrase;
+}
+
+/*
+** Advance the position list iterator specified by the first two 
+** arguments so that it points to the first element with a value greater
+** than or equal to parameter iNext.
+*/
+static void fts3SnippetAdvance(char **ppIter, int *piIter, int iNext){
+  char *pIter = *ppIter;
+  if( pIter ){
+    int iIter = *piIter;
+
+    while( iIter<iNext ){
+      if( 0==(*pIter & 0xFE) ){
+        iIter = -1;
+        pIter = 0;
+        break;
+      }
+      fts3GetDeltaPosition(&pIter, &iIter);
+    }
+
+    *piIter = iIter;
+    *ppIter = pIter;
+  }
+}
+
+/*
+** Advance the snippet iterator to the next candidate snippet.
+*/
+static int fts3SnippetNextCandidate(SnippetIter *pIter){
+  int i;                          /* Loop counter */
+
+  if( pIter->iCurrent<0 ){
+    /* The SnippetIter object has just been initialized. The first snippet
+    ** candidate always starts at offset 0 (even if this candidate has a
+    ** score of 0.0).
+    */
+    pIter->iCurrent = 0;
+
+    /* Advance the 'head' iterator of each phrase to the first offset that
+    ** is greater than or equal to (iNext+nSnippet).
+    */
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      fts3SnippetAdvance(&pPhrase->pHead, &pPhrase->iHead, pIter->nSnippet);
+    }
+  }else{
+    int iStart;
+    int iEnd = 0x7FFFFFFF;
+
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      if( pPhrase->pHead && pPhrase->iHead<iEnd ){
+        iEnd = pPhrase->iHead;
+      }
+    }
+    if( iEnd==0x7FFFFFFF ){
+      return 1;
+    }
+
+    pIter->iCurrent = iStart = iEnd - pIter->nSnippet + 1;
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      fts3SnippetAdvance(&pPhrase->pHead, &pPhrase->iHead, iEnd+1);
+      fts3SnippetAdvance(&pPhrase->pTail, &pPhrase->iTail, iStart);
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Retrieve information about the current candidate snippet of snippet 
+** iterator pIter.
+*/
+static void fts3SnippetDetails(
+  SnippetIter *pIter,             /* Snippet iterator */
+  u64 mCovered,                   /* Bitmask of phrases already covered */
+  int *piToken,                   /* OUT: First token of proposed snippet */
+  int *piScore,                   /* OUT: "Score" for this snippet */
+  u64 *pmCover,                   /* OUT: Bitmask of phrases covered */
+  u64 *pmHighlight                /* OUT: Bitmask of terms to highlight */
+){
+  int iStart = pIter->iCurrent;   /* First token of snippet */
+  int iScore = 0;                 /* Score of this snippet */
+  int i;                          /* Loop counter */
+  u64 mCover = 0;                 /* Mask of phrases covered by this snippet */
+  u64 mHighlight = 0;             /* Mask of tokens to highlight in snippet */
+
+  for(i=0; i<pIter->nPhrase; i++){
+    SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+    if( pPhrase->pTail ){
+      char *pCsr = pPhrase->pTail;
+      int iCsr = pPhrase->iTail;
+
+      while( iCsr<(iStart+pIter->nSnippet) ){
+        int j;
+        u64 mPhrase = (u64)1 << i;
+        u64 mPos = (u64)1 << (iCsr - iStart);
+        assert( iCsr>=iStart );
+        if( (mCover|mCovered)&mPhrase ){
+          iScore++;
+        }else{
+          iScore += 1000;
+        }
+        mCover |= mPhrase;
+
+        for(j=0; j<pPhrase->nToken; j++){
+          mHighlight |= (mPos>>j);
+        }
+
+        if( 0==(*pCsr & 0x0FE) ) break;
+        fts3GetDeltaPosition(&pCsr, &iCsr);
+      }
+    }
+  }
+
+  /* Set the output variables before returning. */
+  *piToken = iStart;
+  *piScore = iScore;
+  *pmCover = mCover;
+  *pmHighlight = mHighlight;
+}
+
+/*
+** This function is an fts3ExprIterate() callback used by fts3BestSnippet().
+** Each invocation populates an element of the SnippetIter.aPhrase[] array.
+*/
+static int fts3SnippetFindPositions(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  SnippetIter *p = (SnippetIter *)ctx;
+  SnippetPhrase *pPhrase = &p->aPhrase[iPhrase];
+  char *pCsr;
+  int rc;
+
+  pPhrase->nToken = pExpr->pPhrase->nToken;
+  rc = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol, &pCsr);
+  assert( rc==SQLITE_OK || pCsr==0 );
+  if( pCsr ){
+    int iFirst = 0;
+    pPhrase->pList = pCsr;
+    fts3GetDeltaPosition(&pCsr, &iFirst);
+    assert( iFirst>=0 );
+    pPhrase->pHead = pCsr;
+    pPhrase->pTail = pCsr;
+    pPhrase->iHead = iFirst;
+    pPhrase->iTail = iFirst;
+  }else{
+    assert( rc!=SQLITE_OK || (
+       pPhrase->pList==0 && pPhrase->pHead==0 && pPhrase->pTail==0 
+    ));
+  }
+
+  return rc;
+}
+
+/*
+** Select the fragment of text consisting of nFragment contiguous tokens 
+** from column iCol that represent the "best" snippet. The best snippet
+** is the snippet with the highest score, where scores are calculated
+** by adding:
+**
+**   (a) +1 point for each occurence of a matchable phrase in the snippet.
+**
+**   (b) +1000 points for the first occurence of each matchable phrase in 
+**       the snippet for which the corresponding mCovered bit is not set.
+**
+** The selected snippet parameters are stored in structure *pFragment before
+** returning. The score of the selected snippet is stored in *piScore
+** before returning.
+*/
+static int fts3BestSnippet(
+  int nSnippet,                   /* Desired snippet length */
+  Fts3Cursor *pCsr,               /* Cursor to create snippet for */
+  int iCol,                       /* Index of column to create snippet from */
+  u64 mCovered,                   /* Mask of phrases already covered */
+  u64 *pmSeen,                    /* IN/OUT: Mask of phrases seen */
+  SnippetFragment *pFragment,     /* OUT: Best snippet found */
+  int *piScore                    /* OUT: Score of snippet pFragment */
+){
+  int rc;                         /* Return Code */
+  int nList;                      /* Number of phrases in expression */
+  SnippetIter sIter;              /* Iterates through snippet candidates */
+  int nByte;                      /* Number of bytes of space to allocate */
+  int iBestScore = -1;            /* Best snippet score found so far */
+  int i;                          /* Loop counter */
+
+  memset(&sIter, 0, sizeof(sIter));
+
+  /* Iterate through the phrases in the expression to count them. The same
+  ** callback makes sure the doclists are loaded for each phrase.
+  */
+  rc = fts3ExprLoadDoclists(pCsr, &nList, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Now that it is known how many phrases there are, allocate and zero
+  ** the required space using malloc().
+  */
+  nByte = sizeof(SnippetPhrase) * nList;
+  sIter.aPhrase = (SnippetPhrase *)sqlite3_malloc(nByte);
+  if( !sIter.aPhrase ){
+    return SQLITE_NOMEM;
+  }
+  memset(sIter.aPhrase, 0, nByte);
+
+  /* Initialize the contents of the SnippetIter object. Then iterate through
+  ** the set of phrases in the expression to populate the aPhrase[] array.
+  */
+  sIter.pCsr = pCsr;
+  sIter.iCol = iCol;
+  sIter.nSnippet = nSnippet;
+  sIter.nPhrase = nList;
+  sIter.iCurrent = -1;
+  (void)fts3ExprIterate(pCsr->pExpr, fts3SnippetFindPositions, (void *)&sIter);
+
+  /* Set the *pmSeen output variable. */
+  for(i=0; i<nList; i++){
+    if( sIter.aPhrase[i].pHead ){
+      *pmSeen |= (u64)1 << i;
+    }
+  }
+
+  /* Loop through all candidate snippets. Store the best snippet in 
+  ** *pFragment. Store its associated 'score' in iBestScore.
+  */
+  pFragment->iCol = iCol;
+  while( !fts3SnippetNextCandidate(&sIter) ){
+    int iPos;
+    int iScore;
+    u64 mCover;
+    u64 mHighlight;
+    fts3SnippetDetails(&sIter, mCovered, &iPos, &iScore, &mCover, &mHighlight);
+    assert( iScore>=0 );
+    if( iScore>iBestScore ){
+      pFragment->iPos = iPos;
+      pFragment->hlmask = mHighlight;
+      pFragment->covered = mCover;
+      iBestScore = iScore;
+    }
+  }
+
+  sqlite3_free(sIter.aPhrase);
+  *piScore = iBestScore;
+  return SQLITE_OK;
+}
+
+
+/*
+** Append a string to the string-buffer passed as the first argument.
+**
+** If nAppend is negative, then the length of the string zAppend is
+** determined using strlen().
+*/
+static int fts3StringAppend(
+  StrBuffer *pStr,                /* Buffer to append to */
+  const char *zAppend,            /* Pointer to data to append to buffer */
+  int nAppend                     /* Size of zAppend in bytes (or -1) */
+){
+  if( nAppend<0 ){
+    nAppend = (int)strlen(zAppend);
+  }
+
+  /* If there is insufficient space allocated at StrBuffer.z, use realloc()
+  ** to grow the buffer until so that it is big enough to accomadate the
+  ** appended data.
+  */
+  if( pStr->n+nAppend+1>=pStr->nAlloc ){
+    int nAlloc = pStr->nAlloc+nAppend+100;
+    char *zNew = sqlite3_realloc(pStr->z, nAlloc);
+    if( !zNew ){
+      return SQLITE_NOMEM;
+    }
+    pStr->z = zNew;
+    pStr->nAlloc = nAlloc;
+  }
+
+  /* Append the data to the string buffer. */
+  memcpy(&pStr->z[pStr->n], zAppend, nAppend);
+  pStr->n += nAppend;
+  pStr->z[pStr->n] = '\0';
+
+  return SQLITE_OK;
+}
+
+/*
+** The fts3BestSnippet() function often selects snippets that end with a
+** query term. That is, the final term of the snippet is always a term
+** that requires highlighting. For example, if 'X' is a highlighted term
+** and '.' is a non-highlighted term, BestSnippet() may select:
+**
+**     ........X.....X
+**
+** This function "shifts" the beginning of the snippet forward in the 
+** document so that there are approximately the same number of 
+** non-highlighted terms to the right of the final highlighted term as there
+** are to the left of the first highlighted term. For example, to this:
+**
+**     ....X.....X....
+**
+** This is done as part of extracting the snippet text, not when selecting
+** the snippet. Snippet selection is done based on doclists only, so there
+** is no way for fts3BestSnippet() to know whether or not the document 
+** actually contains terms that follow the final highlighted term. 
+*/
+static int fts3SnippetShift(
+  Fts3Table *pTab,                /* FTS3 table snippet comes from */
+  int iLangid,                    /* Language id to use in tokenizing */
+  int nSnippet,                   /* Number of tokens desired for snippet */
+  const char *zDoc,               /* Document text to extract snippet from */
+  int nDoc,                       /* Size of buffer zDoc in bytes */
+  int *piPos,                     /* IN/OUT: First token of snippet */
+  u64 *pHlmask                    /* IN/OUT: Mask of tokens to highlight */
+){
+  u64 hlmask = *pHlmask;          /* Local copy of initial highlight-mask */
+
+  if( hlmask ){
+    int nLeft;                    /* Tokens to the left of first highlight */
+    int nRight;                   /* Tokens to the right of last highlight */
+    int nDesired;                 /* Ideal number of tokens to shift forward */
+
+    for(nLeft=0; !(hlmask & ((u64)1 << nLeft)); nLeft++);
+    for(nRight=0; !(hlmask & ((u64)1 << (nSnippet-1-nRight))); nRight++);
+    nDesired = (nLeft-nRight)/2;
+
+    /* Ideally, the start of the snippet should be pushed forward in the
+    ** document nDesired tokens. This block checks if there are actually
+    ** nDesired tokens to the right of the snippet. If so, *piPos and
+    ** *pHlMask are updated to shift the snippet nDesired tokens to the
+    ** right. Otherwise, the snippet is shifted by the number of tokens
+    ** available.
+    */
+    if( nDesired>0 ){
+      int nShift;                 /* Number of tokens to shift snippet by */
+      int iCurrent = 0;           /* Token counter */
+      int rc;                     /* Return Code */
+      sqlite3_tokenizer_module *pMod;
+      sqlite3_tokenizer_cursor *pC;
+      pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
+
+      /* Open a cursor on zDoc/nDoc. Check if there are (nSnippet+nDesired)
+      ** or more tokens in zDoc/nDoc.
+      */
+      rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, iLangid, zDoc, nDoc, &pC);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      while( rc==SQLITE_OK && iCurrent<(nSnippet+nDesired) ){
+        const char *ZDUMMY; int DUMMY1, DUMMY2, DUMMY3;
+        rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
+      }
+      pMod->xClose(pC);
+      if( rc!=SQLITE_OK && rc!=SQLITE_DONE ){ return rc; }
+
+      nShift = (rc==SQLITE_DONE)+iCurrent-nSnippet;
+      assert( nShift<=nDesired );
+      if( nShift>0 ){
+        *piPos += nShift;
+        *pHlmask = hlmask >> nShift;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Extract the snippet text for fragment pFragment from cursor pCsr and
+** append it to string buffer pOut.
+*/
+static int fts3SnippetText(
+  Fts3Cursor *pCsr,               /* FTS3 Cursor */
+  SnippetFragment *pFragment,     /* Snippet to extract */
+  int iFragment,                  /* Fragment number */
+  int isLast,                     /* True for final fragment in snippet */
+  int nSnippet,                   /* Number of tokens in extracted snippet */
+  const char *zOpen,              /* String inserted before highlighted term */
+  const char *zClose,             /* String inserted after highlighted term */
+  const char *zEllipsis,          /* String inserted between snippets */
+  StrBuffer *pOut                 /* Write output here */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc;                         /* Return code */
+  const char *zDoc;               /* Document text to extract snippet from */
+  int nDoc;                       /* Size of zDoc in bytes */
+  int iCurrent = 0;               /* Current token number of document */
+  int iEnd = 0;                   /* Byte offset of end of current token */
+  int isShiftDone = 0;            /* True after snippet is shifted */
+  int iPos = pFragment->iPos;     /* First token of snippet */
+  u64 hlmask = pFragment->hlmask; /* Highlight-mask for snippet */
+  int iCol = pFragment->iCol+1;   /* Query column to extract text from */
+  sqlite3_tokenizer_module *pMod; /* Tokenizer module methods object */
+  sqlite3_tokenizer_cursor *pC;   /* Tokenizer cursor open on zDoc/nDoc */
+  const char *ZDUMMY;             /* Dummy argument used with tokenizer */
+  int DUMMY1;                     /* Dummy argument used with tokenizer */
+  
+  zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol);
+  if( zDoc==0 ){
+    if( sqlite3_column_type(pCsr->pStmt, iCol)!=SQLITE_NULL ){
+      return SQLITE_NOMEM;
+    }
+    return SQLITE_OK;
+  }
+  nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol);
+
+  /* Open a token cursor on the document. */
+  pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
+  rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid, zDoc,nDoc,&pC);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  while( rc==SQLITE_OK ){
+    int iBegin;                   /* Offset in zDoc of start of token */
+    int iFin;                     /* Offset in zDoc of end of token */
+    int isHighlight;              /* True for highlighted terms */
+
+    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iBegin, &iFin, &iCurrent);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_DONE ){
+        /* Special case - the last token of the snippet is also the last token
+        ** of the column. Append any punctuation that occurred between the end
+        ** of the previous token and the end of the document to the output. 
+        ** Then break out of the loop. */
+        rc = fts3StringAppend(pOut, &zDoc[iEnd], -1);
+      }
+      break;
+    }
+    if( iCurrent<iPos ){ continue; }
+
+    if( !isShiftDone ){
+      int n = nDoc - iBegin;
+      rc = fts3SnippetShift(
+          pTab, pCsr->iLangid, nSnippet, &zDoc[iBegin], n, &iPos, &hlmask
+      );
+      isShiftDone = 1;
+
+      /* Now that the shift has been done, check if the initial "..." are
+      ** required. They are required if (a) this is not the first fragment,
+      ** or (b) this fragment does not begin at position 0 of its column. 
+      */
+      if( rc==SQLITE_OK && (iPos>0 || iFragment>0) ){
+        rc = fts3StringAppend(pOut, zEllipsis, -1);
+      }
+      if( rc!=SQLITE_OK || iCurrent<iPos ) continue;
+    }
+
+    if( iCurrent>=(iPos+nSnippet) ){
+      if( isLast ){
+        rc = fts3StringAppend(pOut, zEllipsis, -1);
+      }
+      break;
+    }
+
+    /* Set isHighlight to true if this term should be highlighted. */
+    isHighlight = (hlmask & ((u64)1 << (iCurrent-iPos)))!=0;
+
+    if( iCurrent>iPos ) rc = fts3StringAppend(pOut, &zDoc[iEnd], iBegin-iEnd);
+    if( rc==SQLITE_OK && isHighlight ) rc = fts3StringAppend(pOut, zOpen, -1);
+    if( rc==SQLITE_OK ) rc = fts3StringAppend(pOut, &zDoc[iBegin], iFin-iBegin);
+    if( rc==SQLITE_OK && isHighlight ) rc = fts3StringAppend(pOut, zClose, -1);
+
+    iEnd = iFin;
+  }
+
+  pMod->xClose(pC);
+  return rc;
+}
+
+
+/*
+** This function is used to count the entries in a column-list (a 
+** delta-encoded list of term offsets within a single column of a single 
+** row). When this function is called, *ppCollist should point to the
+** beginning of the first varint in the column-list (the varint that
+** contains the position of the first matching term in the column data).
+** Before returning, *ppCollist is set to point to the first byte after
+** the last varint in the column-list (either the 0x00 signifying the end
+** of the position-list, or the 0x01 that precedes the column number of
+** the next column in the position-list).
+**
+** The number of elements in the column-list is returned.
+*/
+static int fts3ColumnlistCount(char **ppCollist){
+  char *pEnd = *ppCollist;
+  char c = 0;
+  int nEntry = 0;
+
+  /* A column-list is terminated by either a 0x01 or 0x00. */
+  while( 0xFE & (*pEnd | c) ){
+    c = *pEnd++ & 0x80;
+    if( !c ) nEntry++;
+  }
+
+  *ppCollist = pEnd;
+  return nEntry;
+}
+
+/*
+** fts3ExprIterate() callback used to collect the "global" matchinfo stats
+** for a single query. 
+**
+** fts3ExprIterate() callback to load the 'global' elements of a
+** FTS3_MATCHINFO_HITS matchinfo array. The global stats are those elements 
+** of the matchinfo array that are constant for all rows returned by the 
+** current query.
+**
+** Argument pCtx is actually a pointer to a struct of type MatchInfo. This
+** function populates Matchinfo.aMatchinfo[] as follows:
+**
+**   for(iCol=0; iCol<nCol; iCol++){
+**     aMatchinfo[3*iPhrase*nCol + 3*iCol + 1] = X;
+**     aMatchinfo[3*iPhrase*nCol + 3*iCol + 2] = Y;
+**   }
+**
+** where X is the number of matches for phrase iPhrase is column iCol of all
+** rows of the table. Y is the number of rows for which column iCol contains
+** at least one instance of phrase iPhrase.
+**
+** If the phrase pExpr consists entirely of deferred tokens, then all X and
+** Y values are set to nDoc, where nDoc is the number of documents in the 
+** file system. This is done because the full-text index doclist is required
+** to calculate these values properly, and the full-text index doclist is
+** not available for deferred tokens.
+*/
+static int fts3ExprGlobalHitsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number (numbered from zero) */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  MatchInfo *p = (MatchInfo *)pCtx;
+  return sqlite3Fts3EvalPhraseStats(
+      p->pCursor, pExpr, &p->aMatchinfo[3*iPhrase*p->nCol]
+  );
+}
+
+/*
+** fts3ExprIterate() callback used to collect the "local" part of the
+** FTS3_MATCHINFO_HITS array. The local stats are those elements of the 
+** array that are different for each row returned by the query.
+*/
+static int fts3ExprLocalHitsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  int rc = SQLITE_OK;
+  MatchInfo *p = (MatchInfo *)pCtx;
+  int iStart = iPhrase * p->nCol * 3;
+  int i;
+
+  for(i=0; i<p->nCol && rc==SQLITE_OK; i++){
+    char *pCsr;
+    rc = sqlite3Fts3EvalPhrasePoslist(p->pCursor, pExpr, i, &pCsr);
+    if( pCsr ){
+      p->aMatchinfo[iStart+i*3] = fts3ColumnlistCount(&pCsr);
+    }else{
+      p->aMatchinfo[iStart+i*3] = 0;
+    }
+  }
+
+  return rc;
+}
+
+static int fts3MatchinfoCheck(
+  Fts3Table *pTab, 
+  char cArg,
+  char **pzErr
+){
+  if( (cArg==FTS3_MATCHINFO_NPHRASE)
+   || (cArg==FTS3_MATCHINFO_NCOL)
+   || (cArg==FTS3_MATCHINFO_NDOC && pTab->bFts4)
+   || (cArg==FTS3_MATCHINFO_AVGLENGTH && pTab->bFts4)
+   || (cArg==FTS3_MATCHINFO_LENGTH && pTab->bHasDocsize)
+   || (cArg==FTS3_MATCHINFO_LCS)
+   || (cArg==FTS3_MATCHINFO_HITS)
+  ){
+    return SQLITE_OK;
+  }
+  *pzErr = sqlite3_mprintf("unrecognized matchinfo request: %c", cArg);
+  return SQLITE_ERROR;
+}
+
+static int fts3MatchinfoSize(MatchInfo *pInfo, char cArg){
+  int nVal;                       /* Number of integers output by cArg */
+
+  switch( cArg ){
+    case FTS3_MATCHINFO_NDOC:
+    case FTS3_MATCHINFO_NPHRASE: 
+    case FTS3_MATCHINFO_NCOL: 
+      nVal = 1;
+      break;
+
+    case FTS3_MATCHINFO_AVGLENGTH:
+    case FTS3_MATCHINFO_LENGTH:
+    case FTS3_MATCHINFO_LCS:
+      nVal = pInfo->nCol;
+      break;
+
+    default:
+      assert( cArg==FTS3_MATCHINFO_HITS );
+      nVal = pInfo->nCol * pInfo->nPhrase * 3;
+      break;
+  }
+
+  return nVal;
+}
+
+static int fts3MatchinfoSelectDoctotal(
+  Fts3Table *pTab,
+  sqlite3_stmt **ppStmt,
+  sqlite3_int64 *pnDoc,
+  const char **paLen
+){
+  sqlite3_stmt *pStmt;
+  const char *a;
+  sqlite3_int64 nDoc;
+
+  if( !*ppStmt ){
+    int rc = sqlite3Fts3SelectDoctotal(pTab, ppStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  pStmt = *ppStmt;
+  assert( sqlite3_data_count(pStmt)==1 );
+
+  a = sqlite3_column_blob(pStmt, 0);
+  a += sqlite3Fts3GetVarint(a, &nDoc);
+  if( nDoc==0 ) return FTS_CORRUPT_VTAB;
+  *pnDoc = (u32)nDoc;
+
+  if( paLen ) *paLen = a;
+  return SQLITE_OK;
+}
+
+/*
+** An instance of the following structure is used to store state while 
+** iterating through a multi-column position-list corresponding to the
+** hits for a single phrase on a single row in order to calculate the
+** values for a matchinfo() FTS3_MATCHINFO_LCS request.
+*/
+typedef struct LcsIterator LcsIterator;
+struct LcsIterator {
+  Fts3Expr *pExpr;                /* Pointer to phrase expression */
+  int iPosOffset;                 /* Tokens count up to end of this phrase */
+  char *pRead;                    /* Cursor used to iterate through aDoclist */
+  int iPos;                       /* Current position */
+};
+
+/* 
+** If LcsIterator.iCol is set to the following value, the iterator has
+** finished iterating through all offsets for all columns.
+*/
+#define LCS_ITERATOR_FINISHED 0x7FFFFFFF;
+
+static int fts3MatchinfoLcsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number (numbered from zero) */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  LcsIterator *aIter = (LcsIterator *)pCtx;
+  aIter[iPhrase].pExpr = pExpr;
+  return SQLITE_OK;
+}
+
+/*
+** Advance the iterator passed as an argument to the next position. Return
+** 1 if the iterator is at EOF or if it now points to the start of the
+** position list for the next column.
+*/
+static int fts3LcsIteratorAdvance(LcsIterator *pIter){
+  char *pRead = pIter->pRead;
+  sqlite3_int64 iRead;
+  int rc = 0;
+
+  pRead += sqlite3Fts3GetVarint(pRead, &iRead);
+  if( iRead==0 || iRead==1 ){
+    pRead = 0;
+    rc = 1;
+  }else{
+    pIter->iPos += (int)(iRead-2);
+  }
+
+  pIter->pRead = pRead;
+  return rc;
+}
+  
+/*
+** This function implements the FTS3_MATCHINFO_LCS matchinfo() flag. 
+**
+** If the call is successful, the longest-common-substring lengths for each
+** column are written into the first nCol elements of the pInfo->aMatchinfo[] 
+** array before returning. SQLITE_OK is returned in this case.
+**
+** Otherwise, if an error occurs, an SQLite error code is returned and the
+** data written to the first nCol elements of pInfo->aMatchinfo[] is 
+** undefined.
+*/
+static int fts3MatchinfoLcs(Fts3Cursor *pCsr, MatchInfo *pInfo){
+  LcsIterator *aIter;
+  int i;
+  int iCol;
+  int nToken = 0;
+
+  /* Allocate and populate the array of LcsIterator objects. The array
+  ** contains one element for each matchable phrase in the query.
+  **/
+  aIter = sqlite3_malloc(sizeof(LcsIterator) * pCsr->nPhrase);
+  if( !aIter ) return SQLITE_NOMEM;
+  memset(aIter, 0, sizeof(LcsIterator) * pCsr->nPhrase);
+  (void)fts3ExprIterate(pCsr->pExpr, fts3MatchinfoLcsCb, (void*)aIter);
+
+  for(i=0; i<pInfo->nPhrase; i++){
+    LcsIterator *pIter = &aIter[i];
+    nToken -= pIter->pExpr->pPhrase->nToken;
+    pIter->iPosOffset = nToken;
+  }
+
+  for(iCol=0; iCol<pInfo->nCol; iCol++){
+    int nLcs = 0;                 /* LCS value for this column */
+    int nLive = 0;                /* Number of iterators in aIter not at EOF */
+
+    for(i=0; i<pInfo->nPhrase; i++){
+      int rc;
+      LcsIterator *pIt = &aIter[i];
+      rc = sqlite3Fts3EvalPhrasePoslist(pCsr, pIt->pExpr, iCol, &pIt->pRead);
+      if( rc!=SQLITE_OK ) return rc;
+      if( pIt->pRead ){
+        pIt->iPos = pIt->iPosOffset;
+        fts3LcsIteratorAdvance(&aIter[i]);
+        nLive++;
+      }
+    }
+
+    while( nLive>0 ){
+      LcsIterator *pAdv = 0;      /* The iterator to advance by one position */
+      int nThisLcs = 0;           /* LCS for the current iterator positions */
+
+      for(i=0; i<pInfo->nPhrase; i++){
+        LcsIterator *pIter = &aIter[i];
+        if( pIter->pRead==0 ){
+          /* This iterator is already at EOF for this column. */
+          nThisLcs = 0;
+        }else{
+          if( pAdv==0 || pIter->iPos<pAdv->iPos ){
+            pAdv = pIter;
+          }
+          if( nThisLcs==0 || pIter->iPos==pIter[-1].iPos ){
+            nThisLcs++;
+          }else{
+            nThisLcs = 1;
+          }
+          if( nThisLcs>nLcs ) nLcs = nThisLcs;
+        }
+      }
+      if( fts3LcsIteratorAdvance(pAdv) ) nLive--;
+    }
+
+    pInfo->aMatchinfo[iCol] = nLcs;
+  }
+
+  sqlite3_free(aIter);
+  return SQLITE_OK;
+}
+
+/*
+** Populate the buffer pInfo->aMatchinfo[] with an array of integers to
+** be returned by the matchinfo() function. Argument zArg contains the 
+** format string passed as the second argument to matchinfo (or the
+** default value "pcx" if no second argument was specified). The format
+** string has already been validated and the pInfo->aMatchinfo[] array
+** is guaranteed to be large enough for the output.
+**
+** If bGlobal is true, then populate all fields of the matchinfo() output.
+** If it is false, then assume that those fields that do not change between
+** rows (i.e. FTS3_MATCHINFO_NPHRASE, NCOL, NDOC, AVGLENGTH and part of HITS)
+** have already been populated.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error 
+** occurs. If a value other than SQLITE_OK is returned, the state the
+** pInfo->aMatchinfo[] buffer is left in is undefined.
+*/
+static int fts3MatchinfoValues(
+  Fts3Cursor *pCsr,               /* FTS3 cursor object */
+  int bGlobal,                    /* True to grab the global stats */
+  MatchInfo *pInfo,               /* Matchinfo context object */
+  const char *zArg                /* Matchinfo format string */
+){
+  int rc = SQLITE_OK;
+  int i;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  sqlite3_stmt *pSelect = 0;
+
+  for(i=0; rc==SQLITE_OK && zArg[i]; i++){
+
+    switch( zArg[i] ){
+      case FTS3_MATCHINFO_NPHRASE:
+        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nPhrase;
+        break;
+
+      case FTS3_MATCHINFO_NCOL:
+        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nCol;
+        break;
+        
+      case FTS3_MATCHINFO_NDOC:
+        if( bGlobal ){
+          sqlite3_int64 nDoc = 0;
+          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, 0);
+          pInfo->aMatchinfo[0] = (u32)nDoc;
+        }
+        break;
+
+      case FTS3_MATCHINFO_AVGLENGTH: 
+        if( bGlobal ){
+          sqlite3_int64 nDoc;     /* Number of rows in table */
+          const char *a;          /* Aggregate column length array */
+
+          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, &a);
+          if( rc==SQLITE_OK ){
+            int iCol;
+            for(iCol=0; iCol<pInfo->nCol; iCol++){
+              u32 iVal;
+              sqlite3_int64 nToken;
+              a += sqlite3Fts3GetVarint(a, &nToken);
+              iVal = (u32)(((u32)(nToken&0xffffffff)+nDoc/2)/nDoc);
+              pInfo->aMatchinfo[iCol] = iVal;
+            }
+          }
+        }
+        break;
+
+      case FTS3_MATCHINFO_LENGTH: {
+        sqlite3_stmt *pSelectDocsize = 0;
+        rc = sqlite3Fts3SelectDocsize(pTab, pCsr->iPrevId, &pSelectDocsize);
+        if( rc==SQLITE_OK ){
+          int iCol;
+          const char *a = sqlite3_column_blob(pSelectDocsize, 0);
+          for(iCol=0; iCol<pInfo->nCol; iCol++){
+            sqlite3_int64 nToken;
+            a += sqlite3Fts3GetVarint(a, &nToken);
+            pInfo->aMatchinfo[iCol] = (u32)nToken;
+          }
+        }
+        sqlite3_reset(pSelectDocsize);
+        break;
+      }
+
+      case FTS3_MATCHINFO_LCS:
+        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
+        if( rc==SQLITE_OK ){
+          rc = fts3MatchinfoLcs(pCsr, pInfo);
+        }
+        break;
+
+      default: {
+        Fts3Expr *pExpr;
+        assert( zArg[i]==FTS3_MATCHINFO_HITS );
+        pExpr = pCsr->pExpr;
+        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
+        if( rc!=SQLITE_OK ) break;
+        if( bGlobal ){
+          if( pCsr->pDeferred ){
+            rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &pInfo->nDoc, 0);
+            if( rc!=SQLITE_OK ) break;
+          }
+          rc = fts3ExprIterate(pExpr, fts3ExprGlobalHitsCb,(void*)pInfo);
+          if( rc!=SQLITE_OK ) break;
+        }
+        (void)fts3ExprIterate(pExpr, fts3ExprLocalHitsCb,(void*)pInfo);
+        break;
+      }
+    }
+
+    pInfo->aMatchinfo += fts3MatchinfoSize(pInfo, zArg[i]);
+  }
+
+  sqlite3_reset(pSelect);
+  return rc;
+}
+
+
+/*
+** Populate pCsr->aMatchinfo[] with data for the current row. The 
+** 'matchinfo' data is an array of 32-bit unsigned integers (C type u32).
+*/
+static int fts3GetMatchinfo(
+  Fts3Cursor *pCsr,               /* FTS3 Cursor object */
+  const char *zArg                /* Second argument to matchinfo() function */
+){
+  MatchInfo sInfo;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int bGlobal = 0;                /* Collect 'global' stats as well as local */
+
+  memset(&sInfo, 0, sizeof(MatchInfo));
+  sInfo.pCursor = pCsr;
+  sInfo.nCol = pTab->nColumn;
+
+  /* If there is cached matchinfo() data, but the format string for the 
+  ** cache does not match the format string for this request, discard 
+  ** the cached data. */
+  if( pCsr->zMatchinfo && strcmp(pCsr->zMatchinfo, zArg) ){
+    assert( pCsr->aMatchinfo );
+    sqlite3_free(pCsr->aMatchinfo);
+    pCsr->zMatchinfo = 0;
+    pCsr->aMatchinfo = 0;
+  }
+
+  /* If Fts3Cursor.aMatchinfo[] is NULL, then this is the first time the
+  ** matchinfo function has been called for this query. In this case 
+  ** allocate the array used to accumulate the matchinfo data and
+  ** initialize those elements that are constant for every row.
+  */
+  if( pCsr->aMatchinfo==0 ){
+    int nMatchinfo = 0;           /* Number of u32 elements in match-info */
+    int nArg;                     /* Bytes in zArg */
+    int i;                        /* Used to iterate through zArg */
+
+    /* Determine the number of phrases in the query */
+    pCsr->nPhrase = fts3ExprPhraseCount(pCsr->pExpr);
+    sInfo.nPhrase = pCsr->nPhrase;
+
+    /* Determine the number of integers in the buffer returned by this call. */
+    for(i=0; zArg[i]; i++){
+      nMatchinfo += fts3MatchinfoSize(&sInfo, zArg[i]);
+    }
+
+    /* Allocate space for Fts3Cursor.aMatchinfo[] and Fts3Cursor.zMatchinfo. */
+    nArg = (int)strlen(zArg);
+    pCsr->aMatchinfo = (u32 *)sqlite3_malloc(sizeof(u32)*nMatchinfo + nArg + 1);
+    if( !pCsr->aMatchinfo ) return SQLITE_NOMEM;
+
+    pCsr->zMatchinfo = (char *)&pCsr->aMatchinfo[nMatchinfo];
+    pCsr->nMatchinfo = nMatchinfo;
+    memcpy(pCsr->zMatchinfo, zArg, nArg+1);
+    memset(pCsr->aMatchinfo, 0, sizeof(u32)*nMatchinfo);
+    pCsr->isMatchinfoNeeded = 1;
+    bGlobal = 1;
+  }
+
+  sInfo.aMatchinfo = pCsr->aMatchinfo;
+  sInfo.nPhrase = pCsr->nPhrase;
+  if( pCsr->isMatchinfoNeeded ){
+    rc = fts3MatchinfoValues(pCsr, bGlobal, &sInfo, zArg);
+    pCsr->isMatchinfoNeeded = 0;
+  }
+
+  return rc;
+}
+
+/*
+** Implementation of snippet() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Snippet(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr,               /* Cursor object */
+  const char *zStart,             /* Snippet start text - "<b>" */
+  const char *zEnd,               /* Snippet end text - "</b>" */
+  const char *zEllipsis,          /* Snippet ellipsis text - "<b>...</b>" */
+  int iCol,                       /* Extract snippet from this column */
+  int nToken                      /* Approximate number of tokens in snippet */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int i;
+  StrBuffer res = {0, 0, 0};
+
+  /* The returned text includes up to four fragments of text extracted from
+  ** the data in the current row. The first iteration of the for(...) loop
+  ** below attempts to locate a single fragment of text nToken tokens in 
+  ** size that contains at least one instance of all phrases in the query
+  ** expression that appear in the current row. If such a fragment of text
+  ** cannot be found, the second iteration of the loop attempts to locate
+  ** a pair of fragments, and so on.
+  */
+  int nSnippet = 0;               /* Number of fragments in this snippet */
+  SnippetFragment aSnippet[4];    /* Maximum of 4 fragments per snippet */
+  int nFToken = -1;               /* Number of tokens in each fragment */
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  for(nSnippet=1; 1; nSnippet++){
+
+    int iSnip;                    /* Loop counter 0..nSnippet-1 */
+    u64 mCovered = 0;             /* Bitmask of phrases covered by snippet */
+    u64 mSeen = 0;                /* Bitmask of phrases seen by BestSnippet() */
+
+    if( nToken>=0 ){
+      nFToken = (nToken+nSnippet-1) / nSnippet;
+    }else{
+      nFToken = -1 * nToken;
+    }
+
+    for(iSnip=0; iSnip<nSnippet; iSnip++){
+      int iBestScore = -1;        /* Best score of columns checked so far */
+      int iRead;                  /* Used to iterate through columns */
+      SnippetFragment *pFragment = &aSnippet[iSnip];
+
+      memset(pFragment, 0, sizeof(*pFragment));
+
+      /* Loop through all columns of the table being considered for snippets.
+      ** If the iCol argument to this function was negative, this means all
+      ** columns of the FTS3 table. Otherwise, only column iCol is considered.
+      */
+      for(iRead=0; iRead<pTab->nColumn; iRead++){
+        SnippetFragment sF = {0, 0, 0, 0};
+        int iS;
+        if( iCol>=0 && iRead!=iCol ) continue;
+
+        /* Find the best snippet of nFToken tokens in column iRead. */
+        rc = fts3BestSnippet(nFToken, pCsr, iRead, mCovered, &mSeen, &sF, &iS);
+        if( rc!=SQLITE_OK ){
+          goto snippet_out;
+        }
+        if( iS>iBestScore ){
+          *pFragment = sF;
+          iBestScore = iS;
+        }
+      }
+
+      mCovered |= pFragment->covered;
+    }
+
+    /* If all query phrases seen by fts3BestSnippet() are present in at least
+    ** one of the nSnippet snippet fragments, break out of the loop.
+    */
+    assert( (mCovered&mSeen)==mCovered );
+    if( mSeen==mCovered || nSnippet==SizeofArray(aSnippet) ) break;
+  }
+
+  assert( nFToken>0 );
+
+  for(i=0; i<nSnippet && rc==SQLITE_OK; i++){
+    rc = fts3SnippetText(pCsr, &aSnippet[i], 
+        i, (i==nSnippet-1), nFToken, zStart, zEnd, zEllipsis, &res
+    );
+  }
+
+ snippet_out:
+  sqlite3Fts3SegmentsClose(pTab);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+    sqlite3_free(res.z);
+  }else{
+    sqlite3_result_text(pCtx, res.z, -1, sqlite3_free);
+  }
+}
+
+
+typedef struct TermOffset TermOffset;
+typedef struct TermOffsetCtx TermOffsetCtx;
+
+struct TermOffset {
+  char *pList;                    /* Position-list */
+  int iPos;                       /* Position just read from pList */
+  int iOff;                       /* Offset of this term from read positions */
+};
+
+struct TermOffsetCtx {
+  Fts3Cursor *pCsr;
+  int iCol;                       /* Column of table to populate aTerm for */
+  int iTerm;
+  sqlite3_int64 iDocid;
+  TermOffset *aTerm;
+};
+
+/*
+** This function is an fts3ExprIterate() callback used by sqlite3Fts3Offsets().
+*/
+static int fts3ExprTermOffsetInit(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  TermOffsetCtx *p = (TermOffsetCtx *)ctx;
+  int nTerm;                      /* Number of tokens in phrase */
+  int iTerm;                      /* For looping through nTerm phrase terms */
+  char *pList;                    /* Pointer to position list for phrase */
+  int iPos = 0;                   /* First position in position-list */
+  int rc;
+
+  UNUSED_PARAMETER(iPhrase);
+  rc = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol, &pList);
+  nTerm = pExpr->pPhrase->nToken;
+  if( pList ){
+    fts3GetDeltaPosition(&pList, &iPos);
+    assert( iPos>=0 );
+  }
+
+  for(iTerm=0; iTerm<nTerm; iTerm++){
+    TermOffset *pT = &p->aTerm[p->iTerm++];
+    pT->iOff = nTerm-iTerm-1;
+    pT->pList = pList;
+    pT->iPos = iPos;
+  }
+
+  return rc;
+}
+
+/*
+** Implementation of offsets() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Offsets(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr                /* Cursor object */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  sqlite3_tokenizer_module const *pMod = pTab->pTokenizer->pModule;
+  const char *ZDUMMY;             /* Dummy argument used with xNext() */
+  int NDUMMY;                     /* Dummy argument used with xNext() */
+  int rc;                         /* Return Code */
+  int nToken;                     /* Number of tokens in query */
+  int iCol;                       /* Column currently being processed */
+  StrBuffer res = {0, 0, 0};      /* Result string */
+  TermOffsetCtx sCtx;             /* Context for fts3ExprTermOffsetInit() */
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  memset(&sCtx, 0, sizeof(sCtx));
+  assert( pCsr->isRequireSeek==0 );
+
+  /* Count the number of terms in the query */
+  rc = fts3ExprLoadDoclists(pCsr, 0, &nToken);
+  if( rc!=SQLITE_OK ) goto offsets_out;
+
+  /* Allocate the array of TermOffset iterators. */
+  sCtx.aTerm = (TermOffset *)sqlite3_malloc(sizeof(TermOffset)*nToken);
+  if( 0==sCtx.aTerm ){
+    rc = SQLITE_NOMEM;
+    goto offsets_out;
+  }
+  sCtx.iDocid = pCsr->iPrevId;
+  sCtx.pCsr = pCsr;
+
+  /* Loop through the table columns, appending offset information to 
+  ** string-buffer res for each column.
+  */
+  for(iCol=0; iCol<pTab->nColumn; iCol++){
+    sqlite3_tokenizer_cursor *pC; /* Tokenizer cursor */
+    int iStart;
+    int iEnd;
+    int iCurrent;
+    const char *zDoc;
+    int nDoc;
+
+    /* Initialize the contents of sCtx.aTerm[] for column iCol. There is 
+    ** no way that this operation can fail, so the return code from
+    ** fts3ExprIterate() can be discarded.
+    */
+    sCtx.iCol = iCol;
+    sCtx.iTerm = 0;
+    (void)fts3ExprIterate(pCsr->pExpr, fts3ExprTermOffsetInit, (void *)&sCtx);
+
+    /* Retreive the text stored in column iCol. If an SQL NULL is stored 
+    ** in column iCol, jump immediately to the next iteration of the loop.
+    ** If an OOM occurs while retrieving the data (this can happen if SQLite
+    ** needs to transform the data from utf-16 to utf-8), return SQLITE_NOMEM 
+    ** to the caller. 
+    */
+    zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol+1);
+    nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol+1);
+    if( zDoc==0 ){
+      if( sqlite3_column_type(pCsr->pStmt, iCol+1)==SQLITE_NULL ){
+        continue;
+      }
+      rc = SQLITE_NOMEM;
+      goto offsets_out;
+    }
+
+    /* Initialize a tokenizer iterator to iterate through column iCol. */
+    rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid,
+        zDoc, nDoc, &pC
+    );
+    if( rc!=SQLITE_OK ) goto offsets_out;
+
+    rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
+    while( rc==SQLITE_OK ){
+      int i;                      /* Used to loop through terms */
+      int iMinPos = 0x7FFFFFFF;   /* Position of next token */
+      TermOffset *pTerm = 0;      /* TermOffset associated with next token */
+
+      for(i=0; i<nToken; i++){
+        TermOffset *pT = &sCtx.aTerm[i];
+        if( pT->pList && (pT->iPos-pT->iOff)<iMinPos ){
+          iMinPos = pT->iPos-pT->iOff;
+          pTerm = pT;
+        }
+      }
+
+      if( !pTerm ){
+        /* All offsets for this column have been gathered. */
+        rc = SQLITE_DONE;
+      }else{
+        assert( iCurrent<=iMinPos );
+        if( 0==(0xFE&*pTerm->pList) ){
+          pTerm->pList = 0;
+        }else{
+          fts3GetDeltaPosition(&pTerm->pList, &pTerm->iPos);
+        }
+        while( rc==SQLITE_OK && iCurrent<iMinPos ){
+          rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
+        }
+        if( rc==SQLITE_OK ){
+          char aBuffer[64];
+          sqlite3_snprintf(sizeof(aBuffer), aBuffer, 
+              "%d %d %d %d ", iCol, pTerm-sCtx.aTerm, iStart, iEnd-iStart
+          );
+          rc = fts3StringAppend(&res, aBuffer, -1);
+        }else if( rc==SQLITE_DONE && pTab->zContentTbl==0 ){
+          rc = FTS_CORRUPT_VTAB;
+        }
+      }
+    }
+    if( rc==SQLITE_DONE ){
+      rc = SQLITE_OK;
+    }
+
+    pMod->xClose(pC);
+    if( rc!=SQLITE_OK ) goto offsets_out;
+  }
+
+ offsets_out:
+  sqlite3_free(sCtx.aTerm);
+  assert( rc!=SQLITE_DONE );
+  sqlite3Fts3SegmentsClose(pTab);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx,  rc);
+    sqlite3_free(res.z);
+  }else{
+    sqlite3_result_text(pCtx, res.z, res.n-1, sqlite3_free);
+  }
+  return;
+}
+
+/*
+** Implementation of matchinfo() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Matchinfo(
+  sqlite3_context *pContext,      /* Function call context */
+  Fts3Cursor *pCsr,               /* FTS3 table cursor */
+  const char *zArg                /* Second arg to matchinfo() function */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc;
+  int i;
+  const char *zFormat;
+
+  if( zArg ){
+    for(i=0; zArg[i]; i++){
+      char *zErr = 0;
+      if( fts3MatchinfoCheck(pTab, zArg[i], &zErr) ){
+        sqlite3_result_error(pContext, zErr, -1);
+        sqlite3_free(zErr);
+        return;
+      }
+    }
+    zFormat = zArg;
+  }else{
+    zFormat = FTS3_MATCHINFO_DEFAULT;
+  }
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_blob(pContext, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  /* Retrieve matchinfo() data. */
+  rc = fts3GetMatchinfo(pCsr, zFormat);
+  sqlite3Fts3SegmentsClose(pTab);
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pContext, rc);
+  }else{
+    int n = pCsr->nMatchinfo * sizeof(u32);
+    sqlite3_result_blob(pContext, pCsr->aMatchinfo, n, SQLITE_TRANSIENT);
+  }
+}
+
+#endif
+
+/************** End of fts3_snippet.c ****************************************/
+/************** Begin file fts3_unicode.c ************************************/
+/*
+** 2012 May 24
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Implementation of the "unicode" full-text-search tokenizer.
+*/
+
+#ifdef SQLITE_ENABLE_FTS4_UNICODE61
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+
+
+/*
+** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied
+** from the sqlite3 source file utf.c. If this file is compiled as part
+** of the amalgamation, they are not required.
+*/
+#ifndef SQLITE_AMALGAMATION
+
+static const unsigned char sqlite3Utf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+#define READ_UTF8(zIn, zTerm, c)                           \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = sqlite3Utf8Trans1[c-0xc0];                         \
+    while( zIn!=zTerm && (*zIn & 0xc0)==0x80 ){            \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+    if( c<0x80                                             \
+        || (c&0xFFFFF800)==0xD800                          \
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
+  }
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (u8)(c&0xFF);                            \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);                \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);               \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }else{                                               \
+    *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);             \
+    *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);             \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+}
+
+#endif /* ifndef SQLITE_AMALGAMATION */
+
+typedef struct unicode_tokenizer unicode_tokenizer;
+typedef struct unicode_cursor unicode_cursor;
+
+struct unicode_tokenizer {
+  sqlite3_tokenizer base;
+  int bRemoveDiacritic;
+  int nException;
+  int *aiException;
+};
+
+struct unicode_cursor {
+  sqlite3_tokenizer_cursor base;
+  const unsigned char *aInput;    /* Input text being tokenized */
+  int nInput;                     /* Size of aInput[] in bytes */
+  int iOff;                       /* Current offset within aInput[] */
+  int iToken;                     /* Index of next token to be returned */
+  char *zToken;                   /* storage for current token */
+  int nAlloc;                     /* space allocated at zToken */
+};
+
+
+/*
+** Destroy a tokenizer allocated by unicodeCreate().
+*/
+static int unicodeDestroy(sqlite3_tokenizer *pTokenizer){
+  if( pTokenizer ){
+    unicode_tokenizer *p = (unicode_tokenizer *)pTokenizer;
+    sqlite3_free(p->aiException);
+    sqlite3_free(p);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** As part of a tokenchars= or separators= option, the CREATE VIRTUAL TABLE
+** statement has specified that the tokenizer for this table shall consider
+** all characters in string zIn/nIn to be separators (if bAlnum==0) or
+** token characters (if bAlnum==1).
+**
+** For each codepoint in the zIn/nIn string, this function checks if the
+** sqlite3FtsUnicodeIsalnum() function already returns the desired result.
+** If so, no action is taken. Otherwise, the codepoint is added to the 
+** unicode_tokenizer.aiException[] array. For the purposes of tokenization,
+** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all
+** codepoints in the aiException[] array.
+**
+** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic()
+** identifies as a diacritic) occurs in the zIn/nIn string it is ignored.
+** It is not possible to change the behaviour of the tokenizer with respect
+** to these codepoints.
+*/
+static int unicodeAddExceptions(
+  unicode_tokenizer *p,           /* Tokenizer to add exceptions to */
+  int bAlnum,                     /* Replace Isalnum() return value with this */
+  const char *zIn,                /* Array of characters to make exceptions */
+  int nIn                         /* Length of z in bytes */
+){
+  const unsigned char *z = (const unsigned char *)zIn;
+  const unsigned char *zTerm = &z[nIn];
+  int iCode;
+  int nEntry = 0;
+
+  assert( bAlnum==0 || bAlnum==1 );
+
+  while( z<zTerm ){
+    READ_UTF8(z, zTerm, iCode);
+    assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
+    if( sqlite3FtsUnicodeIsalnum(iCode)!=bAlnum 
+     && sqlite3FtsUnicodeIsdiacritic(iCode)==0 
+    ){
+      nEntry++;
+    }
+  }
+
+  if( nEntry ){
+    int *aNew;                    /* New aiException[] array */
+    int nNew;                     /* Number of valid entries in array aNew[] */
+
+    aNew = sqlite3_realloc(p->aiException, (p->nException+nEntry)*sizeof(int));
+    if( aNew==0 ) return SQLITE_NOMEM;
+    nNew = p->nException;
+
+    z = (const unsigned char *)zIn;
+    while( z<zTerm ){
+      READ_UTF8(z, zTerm, iCode);
+      if( sqlite3FtsUnicodeIsalnum(iCode)!=bAlnum 
+       && sqlite3FtsUnicodeIsdiacritic(iCode)==0
+      ){
+        int i, j;
+        for(i=0; i<nNew && aNew[i]<iCode; i++);
+        for(j=nNew; j>i; j--) aNew[j] = aNew[j-1];
+        aNew[i] = iCode;
+        nNew++;
+      }
+    }
+    p->aiException = aNew;
+    p->nException = nNew;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Return true if the p->aiException[] array contains the value iCode.
+*/
+static int unicodeIsException(unicode_tokenizer *p, int iCode){
+  if( p->nException>0 ){
+    int *a = p->aiException;
+    int iLo = 0;
+    int iHi = p->nException-1;
+
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( iCode==a[iTest] ){
+        return 1;
+      }else if( iCode>a[iTest] ){
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Return true if, for the purposes of tokenization, codepoint iCode is
+** considered a token character (not a separator).
+*/
+static int unicodeIsAlnum(unicode_tokenizer *p, int iCode){
+  assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
+  return sqlite3FtsUnicodeIsalnum(iCode) ^ unicodeIsException(p, iCode);
+}
+
+/*
+** Create a new tokenizer instance.
+*/
+static int unicodeCreate(
+  int nArg,                       /* Size of array argv[] */
+  const char * const *azArg,      /* Tokenizer creation arguments */
+  sqlite3_tokenizer **pp          /* OUT: New tokenizer handle */
+){
+  unicode_tokenizer *pNew;        /* New tokenizer object */
+  int i;
+  int rc = SQLITE_OK;
+
+  pNew = (unicode_tokenizer *) sqlite3_malloc(sizeof(unicode_tokenizer));
+  if( pNew==NULL ) return SQLITE_NOMEM;
+  memset(pNew, 0, sizeof(unicode_tokenizer));
+  pNew->bRemoveDiacritic = 1;
+
+  for(i=0; rc==SQLITE_OK && i<nArg; i++){
+    const char *z = azArg[i];
+    int n = strlen(z);
+
+    if( n==19 && memcmp("remove_diacritics=1", z, 19)==0 ){
+      pNew->bRemoveDiacritic = 1;
+    }
+    else if( n==19 && memcmp("remove_diacritics=0", z, 19)==0 ){
+      pNew->bRemoveDiacritic = 0;
+    }
+    else if( n>=11 && memcmp("tokenchars=", z, 11)==0 ){
+      rc = unicodeAddExceptions(pNew, 1, &z[11], n-11);
+    }
+    else if( n>=11 && memcmp("separators=", z, 11)==0 ){
+      rc = unicodeAddExceptions(pNew, 0, &z[11], n-11);
+    }
+    else{
+      /* Unrecognized argument */
+      rc  = SQLITE_ERROR;
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    unicodeDestroy((sqlite3_tokenizer *)pNew);
+    pNew = 0;
+  }
+  *pp = (sqlite3_tokenizer *)pNew;
+  return rc;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in 
+** *ppCursor.
+*/
+static int unicodeOpen(
+  sqlite3_tokenizer *p,           /* The tokenizer */
+  const char *aInput,             /* Input string */
+  int nInput,                     /* Size of string aInput in bytes */
+  sqlite3_tokenizer_cursor **pp   /* OUT: New cursor object */
+){
+  unicode_cursor *pCsr;
+
+  pCsr = (unicode_cursor *)sqlite3_malloc(sizeof(unicode_cursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(unicode_cursor));
+
+  pCsr->aInput = (const unsigned char *)aInput;
+  if( aInput==0 ){
+    pCsr->nInput = 0;
+  }else if( nInput<0 ){
+    pCsr->nInput = (int)strlen(aInput);
+  }else{
+    pCsr->nInput = nInput;
+  }
+
+  *pp = &pCsr->base;
+  UNUSED_PARAMETER(p);
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** simpleOpen() above.
+*/
+static int unicodeClose(sqlite3_tokenizer_cursor *pCursor){
+  unicode_cursor *pCsr = (unicode_cursor *) pCursor;
+  sqlite3_free(pCsr->zToken);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to simpleOpen().
+*/
+static int unicodeNext(
+  sqlite3_tokenizer_cursor *pC,   /* Cursor returned by simpleOpen */
+  const char **paToken,           /* OUT: Token text */
+  int *pnToken,                   /* OUT: Number of bytes at *paToken */
+  int *piStart,                   /* OUT: Starting offset of token */
+  int *piEnd,                     /* OUT: Ending offset of token */
+  int *piPos                      /* OUT: Position integer of token */
+){
+  unicode_cursor *pCsr = (unicode_cursor *)pC;
+  unicode_tokenizer *p = ((unicode_tokenizer *)pCsr->base.pTokenizer);
+  int iCode;
+  char *zOut;
+  const unsigned char *z = &pCsr->aInput[pCsr->iOff];
+  const unsigned char *zStart = z;
+  const unsigned char *zEnd;
+  const unsigned char *zTerm = &pCsr->aInput[pCsr->nInput];
+
+  /* Scan past any delimiter characters before the start of the next token.
+  ** Return SQLITE_DONE early if this takes us all the way to the end of 
+  ** the input.  */
+  while( z<zTerm ){
+    READ_UTF8(z, zTerm, iCode);
+    if( unicodeIsAlnum(p, iCode) ) break;
+    zStart = z;
+  }
+  if( zStart>=zTerm ) return SQLITE_DONE;
+
+  zOut = pCsr->zToken;
+  do {
+    int iOut;
+
+    /* Grow the output buffer if required. */
+    if( (zOut-pCsr->zToken)>=(pCsr->nAlloc-4) ){
+      char *zNew = sqlite3_realloc(pCsr->zToken, pCsr->nAlloc+64);
+      if( !zNew ) return SQLITE_NOMEM;
+      zOut = &zNew[zOut - pCsr->zToken];
+      pCsr->zToken = zNew;
+      pCsr->nAlloc += 64;
+    }
+
+    /* Write the folded case of the last character read to the output */
+    zEnd = z;
+    iOut = sqlite3FtsUnicodeFold(iCode, p->bRemoveDiacritic);
+    if( iOut ){
+      WRITE_UTF8(zOut, iOut);
+    }
+
+    /* If the cursor is not at EOF, read the next character */
+    if( z>=zTerm ) break;
+    READ_UTF8(z, zTerm, iCode);
+  }while( unicodeIsAlnum(p, iCode) 
+       || sqlite3FtsUnicodeIsdiacritic(iCode)
+  );
+
+  /* Set the output variables and return. */
+  pCsr->iOff = (z - pCsr->aInput);
+  *paToken = pCsr->zToken;
+  *pnToken = zOut - pCsr->zToken;
+  *piStart = (zStart - pCsr->aInput);
+  *piEnd = (zEnd - pCsr->aInput);
+  *piPos = pCsr->iToken++;
+  return SQLITE_OK;
+}
+
+/*
+** Set *ppModule to a pointer to the sqlite3_tokenizer_module 
+** structure for the unicode tokenizer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const **ppModule){
+  static const sqlite3_tokenizer_module module = {
+    0,
+    unicodeCreate,
+    unicodeDestroy,
+    unicodeOpen,
+    unicodeClose,
+    unicodeNext,
+    0,
+  };
+  *ppModule = &module;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+#endif /* ifndef SQLITE_ENABLE_FTS4_UNICODE61 */
+
+/************** End of fts3_unicode.c ****************************************/
+/************** Begin file fts3_unicode2.c ***********************************/
+/*
+** 2012 May 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+/*
+** DO NOT EDIT THIS MACHINE GENERATED FILE.
+*/
+
+#if defined(SQLITE_ENABLE_FTS4_UNICODE61)
+#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
+
+/* #include <assert.h> */
+
+/*
+** Return true if the argument corresponds to a unicode codepoint
+** classified as either a letter or a number. Otherwise false.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int c){
+  /* Each unsigned integer in the following array corresponds to a contiguous
+  ** range of unicode codepoints that are not either letters or numbers (i.e.
+  ** codepoints for which this function should return 0).
+  **
+  ** The most significant 22 bits in each 32-bit value contain the first 
+  ** codepoint in the range. The least significant 10 bits are used to store
+  ** the size of the range (always at least 1). In other words, the value 
+  ** ((C<<22) + N) represents a range of N codepoints starting with codepoint 
+  ** C. It is not possible to represent a range larger than 1023 codepoints 
+  ** using this format.
+  */
+  const static unsigned int aEntry[] = {
+    0x00000030, 0x0000E807, 0x00016C06, 0x0001EC2F, 0x0002AC07,
+    0x0002D001, 0x0002D803, 0x0002EC01, 0x0002FC01, 0x00035C01,
+    0x0003DC01, 0x000B0804, 0x000B480E, 0x000B9407, 0x000BB401,
+    0x000BBC81, 0x000DD401, 0x000DF801, 0x000E1002, 0x000E1C01,
+    0x000FD801, 0x00120808, 0x00156806, 0x00162402, 0x00163C01,
+    0x00164437, 0x0017CC02, 0x00180005, 0x00181816, 0x00187802,
+    0x00192C15, 0x0019A804, 0x0019C001, 0x001B5001, 0x001B580F,
+    0x001B9C07, 0x001BF402, 0x001C000E, 0x001C3C01, 0x001C4401,
+    0x001CC01B, 0x001E980B, 0x001FAC09, 0x001FD804, 0x00205804,
+    0x00206C09, 0x00209403, 0x0020A405, 0x0020C00F, 0x00216403,
+    0x00217801, 0x0023901B, 0x00240004, 0x0024E803, 0x0024F812,
+    0x00254407, 0x00258804, 0x0025C001, 0x00260403, 0x0026F001,
+    0x0026F807, 0x00271C02, 0x00272C03, 0x00275C01, 0x00278802,
+    0x0027C802, 0x0027E802, 0x00280403, 0x0028F001, 0x0028F805,
+    0x00291C02, 0x00292C03, 0x00294401, 0x0029C002, 0x0029D401,
+    0x002A0403, 0x002AF001, 0x002AF808, 0x002B1C03, 0x002B2C03,
+    0x002B8802, 0x002BC002, 0x002C0403, 0x002CF001, 0x002CF807,
+    0x002D1C02, 0x002D2C03, 0x002D5802, 0x002D8802, 0x002DC001,
+    0x002E0801, 0x002EF805, 0x002F1803, 0x002F2804, 0x002F5C01,
+    0x002FCC08, 0x00300403, 0x0030F807, 0x00311803, 0x00312804,
+    0x00315402, 0x00318802, 0x0031FC01, 0x00320802, 0x0032F001,
+    0x0032F807, 0x00331803, 0x00332804, 0x00335402, 0x00338802,
+    0x00340802, 0x0034F807, 0x00351803, 0x00352804, 0x00355C01,
+    0x00358802, 0x0035E401, 0x00360802, 0x00372801, 0x00373C06,
+    0x00375801, 0x00376008, 0x0037C803, 0x0038C401, 0x0038D007,
+    0x0038FC01, 0x00391C09, 0x00396802, 0x003AC401, 0x003AD006,
+    0x003AEC02, 0x003B2006, 0x003C041F, 0x003CD00C, 0x003DC417,
+    0x003E340B, 0x003E6424, 0x003EF80F, 0x003F380D, 0x0040AC14,
+    0x00412806, 0x00415804, 0x00417803, 0x00418803, 0x00419C07,
+    0x0041C404, 0x0042080C, 0x00423C01, 0x00426806, 0x0043EC01,
+    0x004D740C, 0x004E400A, 0x00500001, 0x0059B402, 0x005A0001,
+    0x005A6C02, 0x005BAC03, 0x005C4803, 0x005CC805, 0x005D4802,
+    0x005DC802, 0x005ED023, 0x005F6004, 0x005F7401, 0x0060000F,
+    0x0062A401, 0x0064800C, 0x0064C00C, 0x00650001, 0x00651002,
+    0x0066C011, 0x00672002, 0x00677822, 0x00685C05, 0x00687802,
+    0x0069540A, 0x0069801D, 0x0069FC01, 0x006A8007, 0x006AA006,
+    0x006C0005, 0x006CD011, 0x006D6823, 0x006E0003, 0x006E840D,
+    0x006F980E, 0x006FF004, 0x00709014, 0x0070EC05, 0x0071F802,
+    0x00730008, 0x00734019, 0x0073B401, 0x0073C803, 0x00770027,
+    0x0077F004, 0x007EF401, 0x007EFC03, 0x007F3403, 0x007F7403,
+    0x007FB403, 0x007FF402, 0x00800065, 0x0081A806, 0x0081E805,
+    0x00822805, 0x0082801A, 0x00834021, 0x00840002, 0x00840C04,
+    0x00842002, 0x00845001, 0x00845803, 0x00847806, 0x00849401,
+    0x00849C01, 0x0084A401, 0x0084B801, 0x0084E802, 0x00850005,
+    0x00852804, 0x00853C01, 0x00864264, 0x00900027, 0x0091000B,
+    0x0092704E, 0x00940200, 0x009C0475, 0x009E53B9, 0x00AD400A,
+    0x00B39406, 0x00B3BC03, 0x00B3E404, 0x00B3F802, 0x00B5C001,
+    0x00B5FC01, 0x00B7804F, 0x00B8C00C, 0x00BA001A, 0x00BA6C59,
+    0x00BC00D6, 0x00BFC00C, 0x00C00005, 0x00C02019, 0x00C0A807,
+    0x00C0D802, 0x00C0F403, 0x00C26404, 0x00C28001, 0x00C3EC01,
+    0x00C64002, 0x00C6580A, 0x00C70024, 0x00C8001F, 0x00C8A81E,
+    0x00C94001, 0x00C98020, 0x00CA2827, 0x00CB003F, 0x00CC0100,
+    0x01370040, 0x02924037, 0x0293F802, 0x02983403, 0x0299BC10,
+    0x029A7C01, 0x029BC008, 0x029C0017, 0x029C8002, 0x029E2402,
+    0x02A00801, 0x02A01801, 0x02A02C01, 0x02A08C09, 0x02A0D804,
+    0x02A1D004, 0x02A20002, 0x02A2D011, 0x02A33802, 0x02A38012,
+    0x02A3E003, 0x02A4980A, 0x02A51C0D, 0x02A57C01, 0x02A60004,
+    0x02A6CC1B, 0x02A77802, 0x02A8A40E, 0x02A90C01, 0x02A93002,
+    0x02A97004, 0x02A9DC03, 0x02A9EC01, 0x02AAC001, 0x02AAC803,
+    0x02AADC02, 0x02AAF802, 0x02AB0401, 0x02AB7802, 0x02ABAC07,
+    0x02ABD402, 0x02AF8C0B, 0x03600001, 0x036DFC02, 0x036FFC02,
+    0x037FFC02, 0x03E3FC01, 0x03EC7801, 0x03ECA401, 0x03EEC810,
+    0x03F4F802, 0x03F7F002, 0x03F8001A, 0x03F88007, 0x03F8C023,
+    0x03F95013, 0x03F9A004, 0x03FBFC01, 0x03FC040F, 0x03FC6807,
+    0x03FCEC06, 0x03FD6C0B, 0x03FF8007, 0x03FFA007, 0x03FFE405,
+    0x04040003, 0x0404DC09, 0x0405E411, 0x0406400C, 0x0407402E,
+    0x040E7C01, 0x040F4001, 0x04215C01, 0x04247C01, 0x0424FC01,
+    0x04280403, 0x04281402, 0x04283004, 0x0428E003, 0x0428FC01,
+    0x04294009, 0x0429FC01, 0x042CE407, 0x04400003, 0x0440E016,
+    0x04420003, 0x0442C012, 0x04440003, 0x04449C0E, 0x04450004,
+    0x04460003, 0x0446CC0E, 0x04471404, 0x045AAC0D, 0x0491C004,
+    0x05BD442E, 0x05BE3C04, 0x074000F6, 0x07440027, 0x0744A4B5,
+    0x07480046, 0x074C0057, 0x075B0401, 0x075B6C01, 0x075BEC01,
+    0x075C5401, 0x075CD401, 0x075D3C01, 0x075DBC01, 0x075E2401,
+    0x075EA401, 0x075F0C01, 0x07BBC002, 0x07C0002C, 0x07C0C064,
+    0x07C2800F, 0x07C2C40E, 0x07C3040F, 0x07C3440F, 0x07C4401F,
+    0x07C4C03C, 0x07C5C02B, 0x07C7981D, 0x07C8402B, 0x07C90009,
+    0x07C94002, 0x07CC0021, 0x07CCC006, 0x07CCDC46, 0x07CE0014,
+    0x07CE8025, 0x07CF1805, 0x07CF8011, 0x07D0003F, 0x07D10001,
+    0x07D108B6, 0x07D3E404, 0x07D4003E, 0x07D50004, 0x07D54018,
+    0x07D7EC46, 0x07D9140B, 0x07DA0046, 0x07DC0074, 0x38000401,
+    0x38008060, 0x380400F0, 0x3C000001, 0x3FFFF401, 0x40000001,
+    0x43FFF401,
+  };
+  static const unsigned int aAscii[4] = {
+    0xFFFFFFFF, 0xFC00FFFF, 0xF8000001, 0xF8000001,
+  };
+
+  if( c<128 ){
+    return ( (aAscii[c >> 5] & (1 << (c & 0x001F)))==0 );
+  }else if( c<(1<<22) ){
+    unsigned int key = (((unsigned int)c)<<10) | 0x000003FF;
+    int iRes;
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( key >= aEntry[iTest] ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+    assert( aEntry[0]<key );
+    assert( key>=aEntry[iRes] );
+    return (((unsigned int)c) >= ((aEntry[iRes]>>10) + (aEntry[iRes]&0x3FF)));
+  }
+  return 1;
+}
+
+
+/*
+** If the argument is a codepoint corresponding to a lowercase letter
+** in the ASCII range with a diacritic added, return the codepoint
+** of the ASCII letter only. For example, if passed 235 - "LATIN
+** SMALL LETTER E WITH DIAERESIS" - return 65 ("LATIN SMALL LETTER
+** E"). The resuls of passing a codepoint that corresponds to an
+** uppercase letter are undefined.
+*/
+static int remove_diacritic(int c){
+  unsigned short aDia[] = {
+        0,  1797,  1848,  1859,  1891,  1928,  1940,  1995, 
+     2024,  2040,  2060,  2110,  2168,  2206,  2264,  2286, 
+     2344,  2383,  2472,  2488,  2516,  2596,  2668,  2732, 
+     2782,  2842,  2894,  2954,  2984,  3000,  3028,  3336, 
+     3456,  3696,  3712,  3728,  3744,  3896,  3912,  3928, 
+     3968,  4008,  4040,  4106,  4138,  4170,  4202,  4234, 
+     4266,  4296,  4312,  4344,  4408,  4424,  4472,  4504, 
+     6148,  6198,  6264,  6280,  6360,  6429,  6505,  6529, 
+    61448, 61468, 61534, 61592, 61642, 61688, 61704, 61726, 
+    61784, 61800, 61836, 61880, 61914, 61948, 61998, 62122, 
+    62154, 62200, 62218, 62302, 62364, 62442, 62478, 62536, 
+    62554, 62584, 62604, 62640, 62648, 62656, 62664, 62730, 
+    62924, 63050, 63082, 63274, 63390, 
+  };
+  char aChar[] = {
+    '\0', 'a',  'c',  'e',  'i',  'n',  'o',  'u',  'y',  'y',  'a',  'c',  
+    'd',  'e',  'e',  'g',  'h',  'i',  'j',  'k',  'l',  'n',  'o',  'r',  
+    's',  't',  'u',  'u',  'w',  'y',  'z',  'o',  'u',  'a',  'i',  'o',  
+    'u',  'g',  'k',  'o',  'j',  'g',  'n',  'a',  'e',  'i',  'o',  'r',  
+    'u',  's',  't',  'h',  'a',  'e',  'o',  'y',  '\0', '\0', '\0', '\0', 
+    '\0', '\0', '\0', '\0', 'a',  'b',  'd',  'd',  'e',  'f',  'g',  'h',  
+    'h',  'i',  'k',  'l',  'l',  'm',  'n',  'p',  'r',  'r',  's',  't',  
+    'u',  'v',  'w',  'w',  'x',  'y',  'z',  'h',  't',  'w',  'y',  'a',  
+    'e',  'i',  'o',  'u',  'y',  
+  };
+
+  unsigned int key = (((unsigned int)c)<<3) | 0x00000007;
+  int iRes = 0;
+  int iHi = sizeof(aDia)/sizeof(aDia[0]) - 1;
+  int iLo = 0;
+  while( iHi>=iLo ){
+    int iTest = (iHi + iLo) / 2;
+    if( key >= aDia[iTest] ){
+      iRes = iTest;
+      iLo = iTest+1;
+    }else{
+      iHi = iTest-1;
+    }
+  }
+  assert( key>=aDia[iRes] );
+  return ((c > (aDia[iRes]>>3) + (aDia[iRes]&0x07)) ? c : (int)aChar[iRes]);
+};
+
+
+/*
+** Return true if the argument interpreted as a unicode codepoint
+** is a diacritical modifier character.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int c){
+  unsigned int mask0 = 0x08029FDF;
+  unsigned int mask1 = 0x000361F8;
+  if( c<768 || c>817 ) return 0;
+  return (c < 768+32) ?
+      (mask0 & (1 << (c-768))) :
+      (mask1 & (1 << (c-768-32)));
+}
+
+
+/*
+** Interpret the argument as a unicode codepoint. If the codepoint
+** is an upper case character that has a lower case equivalent,
+** return the codepoint corresponding to the lower case version.
+** Otherwise, return a copy of the argument.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int c, int bRemoveDiacritic){
+  /* Each entry in the following array defines a rule for folding a range
+  ** of codepoints to lower case. The rule applies to a range of nRange
+  ** codepoints starting at codepoint iCode.
+  **
+  ** If the least significant bit in flags is clear, then the rule applies
+  ** to all nRange codepoints (i.e. all nRange codepoints are upper case and
+  ** need to be folded). Or, if it is set, then the rule only applies to
+  ** every second codepoint in the range, starting with codepoint C.
+  **
+  ** The 7 most significant bits in flags are an index into the aiOff[]
+  ** array. If a specific codepoint C does require folding, then its lower
+  ** case equivalent is ((C + aiOff[flags>>1]) & 0xFFFF).
+  **
+  ** The contents of this array are generated by parsing the CaseFolding.txt
+  ** file distributed as part of the "Unicode Character Database". See
+  ** http://www.unicode.org for details.
+  */
+  static const struct TableEntry {
+    unsigned short iCode;
+    unsigned char flags;
+    unsigned char nRange;
+  } aEntry[] = {
+    {65, 14, 26},          {181, 64, 1},          {192, 14, 23},
+    {216, 14, 7},          {256, 1, 48},          {306, 1, 6},
+    {313, 1, 16},          {330, 1, 46},          {376, 116, 1},
+    {377, 1, 6},           {383, 104, 1},         {385, 50, 1},
+    {386, 1, 4},           {390, 44, 1},          {391, 0, 1},
+    {393, 42, 2},          {395, 0, 1},           {398, 32, 1},
+    {399, 38, 1},          {400, 40, 1},          {401, 0, 1},
+    {403, 42, 1},          {404, 46, 1},          {406, 52, 1},
+    {407, 48, 1},          {408, 0, 1},           {412, 52, 1},
+    {413, 54, 1},          {415, 56, 1},          {416, 1, 6},
+    {422, 60, 1},          {423, 0, 1},           {425, 60, 1},
+    {428, 0, 1},           {430, 60, 1},          {431, 0, 1},
+    {433, 58, 2},          {435, 1, 4},           {439, 62, 1},
+    {440, 0, 1},           {444, 0, 1},           {452, 2, 1},
+    {453, 0, 1},           {455, 2, 1},           {456, 0, 1},
+    {458, 2, 1},           {459, 1, 18},          {478, 1, 18},
+    {497, 2, 1},           {498, 1, 4},           {502, 122, 1},
+    {503, 134, 1},         {504, 1, 40},          {544, 110, 1},
+    {546, 1, 18},          {570, 70, 1},          {571, 0, 1},
+    {573, 108, 1},         {574, 68, 1},          {577, 0, 1},
+    {579, 106, 1},         {580, 28, 1},          {581, 30, 1},
+    {582, 1, 10},          {837, 36, 1},          {880, 1, 4},
+    {886, 0, 1},           {902, 18, 1},          {904, 16, 3},
+    {908, 26, 1},          {910, 24, 2},          {913, 14, 17},
+    {931, 14, 9},          {962, 0, 1},           {975, 4, 1},
+    {976, 140, 1},         {977, 142, 1},         {981, 146, 1},
+    {982, 144, 1},         {984, 1, 24},          {1008, 136, 1},
+    {1009, 138, 1},        {1012, 130, 1},        {1013, 128, 1},
+    {1015, 0, 1},          {1017, 152, 1},        {1018, 0, 1},
+    {1021, 110, 3},        {1024, 34, 16},        {1040, 14, 32},
+    {1120, 1, 34},         {1162, 1, 54},         {1216, 6, 1},
+    {1217, 1, 14},         {1232, 1, 88},         {1329, 22, 38},
+    {4256, 66, 38},        {4295, 66, 1},         {4301, 66, 1},
+    {7680, 1, 150},        {7835, 132, 1},        {7838, 96, 1},
+    {7840, 1, 96},         {7944, 150, 8},        {7960, 150, 6},
+    {7976, 150, 8},        {7992, 150, 8},        {8008, 150, 6},
+    {8025, 151, 8},        {8040, 150, 8},        {8072, 150, 8},
+    {8088, 150, 8},        {8104, 150, 8},        {8120, 150, 2},
+    {8122, 126, 2},        {8124, 148, 1},        {8126, 100, 1},
+    {8136, 124, 4},        {8140, 148, 1},        {8152, 150, 2},
+    {8154, 120, 2},        {8168, 150, 2},        {8170, 118, 2},
+    {8172, 152, 1},        {8184, 112, 2},        {8186, 114, 2},
+    {8188, 148, 1},        {8486, 98, 1},         {8490, 92, 1},
+    {8491, 94, 1},         {8498, 12, 1},         {8544, 8, 16},
+    {8579, 0, 1},          {9398, 10, 26},        {11264, 22, 47},
+    {11360, 0, 1},         {11362, 88, 1},        {11363, 102, 1},
+    {11364, 90, 1},        {11367, 1, 6},         {11373, 84, 1},
+    {11374, 86, 1},        {11375, 80, 1},        {11376, 82, 1},
+    {11378, 0, 1},         {11381, 0, 1},         {11390, 78, 2},
+    {11392, 1, 100},       {11499, 1, 4},         {11506, 0, 1},
+    {42560, 1, 46},        {42624, 1, 24},        {42786, 1, 14},
+    {42802, 1, 62},        {42873, 1, 4},         {42877, 76, 1},
+    {42878, 1, 10},        {42891, 0, 1},         {42893, 74, 1},
+    {42896, 1, 4},         {42912, 1, 10},        {42922, 72, 1},
+    {65313, 14, 26},       
+  };
+  static const unsigned short aiOff[] = {
+   1,     2,     8,     15,    16,    26,    28,    32,    
+   37,    38,    40,    48,    63,    64,    69,    71,    
+   79,    80,    116,   202,   203,   205,   206,   207,   
+   209,   210,   211,   213,   214,   217,   218,   219,   
+   775,   7264,  10792, 10795, 23228, 23256, 30204, 54721, 
+   54753, 54754, 54756, 54787, 54793, 54809, 57153, 57274, 
+   57921, 58019, 58363, 61722, 65268, 65341, 65373, 65406, 
+   65408, 65410, 65415, 65424, 65436, 65439, 65450, 65462, 
+   65472, 65476, 65478, 65480, 65482, 65488, 65506, 65511, 
+   65514, 65521, 65527, 65528, 65529, 
+  };
+
+  int ret = c;
+
+  assert( c>=0 );
+  assert( sizeof(unsigned short)==2 && sizeof(unsigned char)==1 );
+
+  if( c<128 ){
+    if( c>='A' && c<='Z' ) ret = c + ('a' - 'A');
+  }else if( c<65536 ){
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    int iRes = -1;
+
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      int cmp = (c - aEntry[iTest].iCode);
+      if( cmp>=0 ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+    assert( iRes<0 || c>=aEntry[iRes].iCode );
+
+    if( iRes>=0 ){
+      const struct TableEntry *p = &aEntry[iRes];
+      if( c<(p->iCode + p->nRange) && 0==(0x01 & p->flags & (p->iCode ^ c)) ){
+        ret = (c + (aiOff[p->flags>>1])) & 0x0000FFFF;
+        assert( ret>0 );
+      }
+    }
+
+    if( bRemoveDiacritic ) ret = remove_diacritic(ret);
+  }
+  
+  else if( c>=66560 && c<66600 ){
+    ret = c + 40;
+  }
+
+  return ret;
+}
+#endif /* defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4) */
+#endif /* !defined(SQLITE_ENABLE_FTS4_UNICODE61) */
+
+/************** End of fts3_unicode2.c ***************************************/
 /************** Begin file rtree.c *******************************************/
 /*
 ** 2001 September 15
@@ -99287,8 +132222,45 @@ SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(
 *************************************************************************
 ** This file contains code for implementations of the r-tree and r*-tree
 ** algorithms packaged as an SQLite virtual table module.
+*/
+
+/*
+** Database Format of R-Tree Tables
+** --------------------------------
 **
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+** The data structure for a single virtual r-tree table is stored in three 
+** native SQLite tables declared as follows. In each case, the '%' character
+** in the table name is replaced with the user-supplied name of the r-tree
+** table.
+**
+**   CREATE TABLE %_node(nodeno INTEGER PRIMARY KEY, data BLOB)
+**   CREATE TABLE %_parent(nodeno INTEGER PRIMARY KEY, parentnode INTEGER)
+**   CREATE TABLE %_rowid(rowid INTEGER PRIMARY KEY, nodeno INTEGER)
+**
+** The data for each node of the r-tree structure is stored in the %_node
+** table. For each node that is not the root node of the r-tree, there is
+** an entry in the %_parent table associating the node with its parent.
+** And for each row of data in the table, there is an entry in the %_rowid
+** table that maps from the entries rowid to the id of the node that it
+** is stored on.
+**
+** The root node of an r-tree always exists, even if the r-tree table is
+** empty. The nodeno of the root node is always 1. All other nodes in the
+** table must be the same size as the root node. The content of each node
+** is formatted as follows:
+**
+**   1. If the node is the root node (node 1), then the first 2 bytes
+**      of the node contain the tree depth as a big-endian integer.
+**      For non-root nodes, the first 2 bytes are left unused.
+**
+**   2. The next 2 bytes contain the number of entries currently 
+**      stored in the node.
+**
+**   3. The remainder of the node contains the node entries. Each entry
+**      consists of a single 8-byte integer followed by an even number
+**      of 4-byte coordinates. For leaf nodes the integer is the rowid
+**      of a record. For internal nodes it is the node number of a
+**      child page.
 */
 
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RTREE)
@@ -99331,24 +132303,38 @@ SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(
   #define AssignCells splitNodeStartree
 #endif
 
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG) 
+# define NDEBUG 1
+#endif
 
 #ifndef SQLITE_CORE
   SQLITE_EXTENSION_INIT1
 #else
 #endif
 
+/* #include <string.h> */
+/* #include <assert.h> */
 
 #ifndef SQLITE_AMALGAMATION
+#include "sqlite3rtree.h"
 typedef sqlite3_int64 i64;
 typedef unsigned char u8;
 typedef unsigned int u32;
 #endif
 
+/*  The following macro is used to suppress compiler warnings.
+*/
+#ifndef UNUSED_PARAMETER
+# define UNUSED_PARAMETER(x) (void)(x)
+#endif
+
 typedef struct Rtree Rtree;
 typedef struct RtreeCursor RtreeCursor;
 typedef struct RtreeNode RtreeNode;
 typedef struct RtreeCell RtreeCell;
 typedef struct RtreeConstraint RtreeConstraint;
+typedef struct RtreeMatchArg RtreeMatchArg;
+typedef struct RtreeGeomCallback RtreeGeomCallback;
 typedef union RtreeCoord RtreeCoord;
 
 /* The rtree may have between 1 and RTREE_MAX_DIMENSIONS dimensions. */
@@ -99405,6 +132391,19 @@ struct Rtree {
 #define RTREE_COORD_REAL32 0
 #define RTREE_COORD_INT32  1
 
+/*
+** If SQLITE_RTREE_INT_ONLY is defined, then this virtual table will
+** only deal with integer coordinates.  No floating point operations
+** will be done.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+  typedef sqlite3_int64 RtreeDValue;       /* High accuracy coordinate */
+  typedef int RtreeValue;                  /* Low accuracy coordinate */
+#else
+  typedef double RtreeDValue;              /* High accuracy coordinate */
+  typedef float RtreeValue;                /* Low accuracy coordinate */
+#endif
+
 /*
 ** The minimum number of cells allowed for a node is a third of the 
 ** maximum. In Gutman's notation:
@@ -99418,6 +132417,15 @@ struct Rtree {
 #define RTREE_REINSERT(p) RTREE_MINCELLS(p)
 #define RTREE_MAXCELLS 51
 
+/*
+** The smallest possible node-size is (512-64)==448 bytes. And the largest
+** supported cell size is 48 bytes (8 byte rowid + ten 4 byte coordinates).
+** Therefore all non-root nodes must contain at least 3 entries. Since 
+** 2^40 is greater than 2^64, an r-tree structure always has a depth of
+** 40 or less.
+*/
+#define RTREE_MAX_DEPTH 40
+
 /* 
 ** An rtree cursor object.
 */
@@ -99431,54 +132439,47 @@ struct RtreeCursor {
 };
 
 union RtreeCoord {
-  float f;
+  RtreeValue f;
   int i;
 };
 
 /*
 ** The argument is an RtreeCoord. Return the value stored within the RtreeCoord
-** formatted as a double. This macro assumes that local variable pRtree points
-** to the Rtree structure associated with the RtreeCoord.
+** formatted as a RtreeDValue (double or int64). This macro assumes that local
+** variable pRtree points to the Rtree structure associated with the
+** RtreeCoord.
 */
-#define DCOORD(coord) (                           \
-  (pRtree->eCoordType==RTREE_COORD_REAL32) ?      \
-    ((double)coord.f) :                           \
-    ((double)coord.i)                             \
-)
+#ifdef SQLITE_RTREE_INT_ONLY
+# define DCOORD(coord) ((RtreeDValue)coord.i)
+#else
+# define DCOORD(coord) (                           \
+    (pRtree->eCoordType==RTREE_COORD_REAL32) ?      \
+      ((double)coord.f) :                           \
+      ((double)coord.i)                             \
+  )
+#endif
 
 /*
 ** A search constraint.
 */
 struct RtreeConstraint {
-  int iCoord;                       /* Index of constrained coordinate */
-  int op;                           /* Constraining operation */
-  double rValue;                    /* Constraint value. */
+  int iCoord;                     /* Index of constrained coordinate */
+  int op;                         /* Constraining operation */
+  RtreeDValue rValue;             /* Constraint value. */
+  int (*xGeom)(sqlite3_rtree_geometry*, int, RtreeDValue*, int*);
+  sqlite3_rtree_geometry *pGeom;  /* Constraint callback argument for a MATCH */
 };
 
 /* Possible values for RtreeConstraint.op */
-#define RTREE_EQ 0x41
-#define RTREE_LE 0x42
-#define RTREE_LT 0x43
-#define RTREE_GE 0x44
-#define RTREE_GT 0x45
+#define RTREE_EQ    0x41
+#define RTREE_LE    0x42
+#define RTREE_LT    0x43
+#define RTREE_GE    0x44
+#define RTREE_GT    0x45
+#define RTREE_MATCH 0x46
 
 /* 
 ** An rtree structure node.
-**
-** Data format (RtreeNode.zData):
-**
-**   1. If the node is the root node (node 1), then the first 2 bytes
-**      of the node contain the tree depth as a big-endian integer.
-**      For non-root nodes, the first 2 bytes are left unused.
-**
-**   2. The next 2 bytes contain the number of entries currently 
-**      stored in the node.
-**
-**   3. The remainder of the node contains the node entries. Each entry
-**      consists of a single 8-byte integer followed by an even number
-**      of 4-byte coordinates. For leaf nodes the integer is the rowid
-**      of a record. For internal nodes it is the node number of a
-**      child page.
 */
 struct RtreeNode {
   RtreeNode *pParent;               /* Parent node */
@@ -99498,6 +132499,40 @@ struct RtreeCell {
   RtreeCoord aCoord[RTREE_MAX_DIMENSIONS*2];
 };
 
+
+/*
+** Value for the first field of every RtreeMatchArg object. The MATCH
+** operator tests that the first field of a blob operand matches this
+** value to avoid operating on invalid blobs (which could cause a segfault).
+*/
+#define RTREE_GEOMETRY_MAGIC 0x891245AB
+
+/*
+** An instance of this structure must be supplied as a blob argument to
+** the right-hand-side of an SQL MATCH operator used to constrain an
+** r-tree query.
+*/
+struct RtreeMatchArg {
+  u32 magic;                      /* Always RTREE_GEOMETRY_MAGIC */
+  int (*xGeom)(sqlite3_rtree_geometry *, int, RtreeDValue*, int *);
+  void *pContext;
+  int nParam;
+  RtreeDValue aParam[1];
+};
+
+/*
+** When a geometry callback is created (see sqlite3_rtree_geometry_callback),
+** a single instance of the following structure is allocated. It is used
+** as the context for the user-function created by by s_r_g_c(). The object
+** is eventually deleted by the destructor mechanism provided by
+** sqlite3_create_function_v2() (which is called by s_r_g_c() to create
+** the geometry callback function).
+*/
+struct RtreeGeomCallback {
+  int (*xGeom)(sqlite3_rtree_geometry*, int, RtreeDValue*, int*);
+  void *pContext;
+};
+
 #ifndef MAX
 # define MAX(x,y) ((x) < (y) ? (y) : (x))
 #endif
@@ -99580,10 +132615,8 @@ static void nodeReference(RtreeNode *p){
 ** Clear the content of node p (set all bytes to 0x00).
 */
 static void nodeZero(Rtree *pRtree, RtreeNode *p){
-  if( p ){
-    memset(&p->zData[2], 0, pRtree->iNodeSize-2);
-    p->isDirty = 1;
-  }
+  memset(&p->zData[2], 0, pRtree->iNodeSize-2);
+  p->isDirty = 1;
 }
 
 /*
@@ -99603,7 +132636,6 @@ static int nodeHash(i64 iNode){
 */
 static RtreeNode *nodeHashLookup(Rtree *pRtree, i64 iNode){
   RtreeNode *p;
-  assert( iNode!=0 );
   for(p=pRtree->aHash[nodeHash(iNode)]; p && p->iNode!=iNode; p=p->pNext);
   return p;
 }
@@ -99612,13 +132644,11 @@ static RtreeNode *nodeHashLookup(Rtree *pRtree, i64 iNode){
 ** Add node pNode to the node hash table.
 */
 static void nodeHashInsert(Rtree *pRtree, RtreeNode *pNode){
-  if( pNode ){
-    int iHash;
-    assert( pNode->pNext==0 );
-    iHash = nodeHash(pNode->iNode);
-    pNode->pNext = pRtree->aHash[iHash];
-    pRtree->aHash[iHash] = pNode;
-  }
+  int iHash;
+  assert( pNode->pNext==0 );
+  iHash = nodeHash(pNode->iNode);
+  pNode->pNext = pRtree->aHash[iHash];
+  pRtree->aHash[iHash] = pNode;
 }
 
 /*
@@ -99640,11 +132670,11 @@ static void nodeHashDelete(Rtree *pRtree, RtreeNode *pNode){
 ** assigned a node number when nodeWrite() is called to write the
 ** node contents out to the database.
 */
-static RtreeNode *nodeNew(Rtree *pRtree, RtreeNode *pParent, int zero){
+static RtreeNode *nodeNew(Rtree *pRtree, RtreeNode *pParent){
   RtreeNode *pNode;
   pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode) + pRtree->iNodeSize);
   if( pNode ){
-    memset(pNode, 0, sizeof(RtreeNode) + (zero?pRtree->iNodeSize:0));
+    memset(pNode, 0, sizeof(RtreeNode) + pRtree->iNodeSize);
     pNode->zData = (u8 *)&pNode[1];
     pNode->nRef = 1;
     pNode->pParent = pParent;
@@ -99665,6 +132695,7 @@ nodeAcquire(
   RtreeNode **ppNode         /* OUT: Acquired node */
 ){
   int rc;
+  int rc2 = SQLITE_OK;
   RtreeNode *pNode;
 
   /* Check if the requested node is already in the hash table. If so,
@@ -99681,39 +132712,64 @@ nodeAcquire(
     return SQLITE_OK;
   }
 
-  pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode) + pRtree->iNodeSize);
-  if( !pNode ){
-    *ppNode = 0;
-    return SQLITE_NOMEM;
-  }
-  pNode->pParent = pParent;
-  pNode->zData = (u8 *)&pNode[1];
-  pNode->nRef = 1;
-  pNode->iNode = iNode;
-  pNode->isDirty = 0;
-  pNode->pNext = 0;
-
   sqlite3_bind_int64(pRtree->pReadNode, 1, iNode);
   rc = sqlite3_step(pRtree->pReadNode);
   if( rc==SQLITE_ROW ){
     const u8 *zBlob = sqlite3_column_blob(pRtree->pReadNode, 0);
-    memcpy(pNode->zData, zBlob, pRtree->iNodeSize);
-    nodeReference(pParent);
+    if( pRtree->iNodeSize==sqlite3_column_bytes(pRtree->pReadNode, 0) ){
+      pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode)+pRtree->iNodeSize);
+      if( !pNode ){
+        rc2 = SQLITE_NOMEM;
+      }else{
+        pNode->pParent = pParent;
+        pNode->zData = (u8 *)&pNode[1];
+        pNode->nRef = 1;
+        pNode->iNode = iNode;
+        pNode->isDirty = 0;
+        pNode->pNext = 0;
+        memcpy(pNode->zData, zBlob, pRtree->iNodeSize);
+        nodeReference(pParent);
+      }
+    }
+  }
+  rc = sqlite3_reset(pRtree->pReadNode);
+  if( rc==SQLITE_OK ) rc = rc2;
+
+  /* If the root node was just loaded, set pRtree->iDepth to the height
+  ** of the r-tree structure. A height of zero means all data is stored on
+  ** the root node. A height of one means the children of the root node
+  ** are the leaves, and so on. If the depth as specified on the root node
+  ** is greater than RTREE_MAX_DEPTH, the r-tree structure must be corrupt.
+  */
+  if( pNode && iNode==1 ){
+    pRtree->iDepth = readInt16(pNode->zData);
+    if( pRtree->iDepth>RTREE_MAX_DEPTH ){
+      rc = SQLITE_CORRUPT_VTAB;
+    }
+  }
+
+  /* If no error has occurred so far, check if the "number of entries"
+  ** field on the node is too large. If so, set the return code to 
+  ** SQLITE_CORRUPT_VTAB.
+  */
+  if( pNode && rc==SQLITE_OK ){
+    if( NCELL(pNode)>((pRtree->iNodeSize-4)/pRtree->nBytesPerCell) ){
+      rc = SQLITE_CORRUPT_VTAB;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( pNode!=0 ){
+      nodeHashInsert(pRtree, pNode);
+    }else{
+      rc = SQLITE_CORRUPT_VTAB;
+    }
+    *ppNode = pNode;
   }else{
     sqlite3_free(pNode);
-    pNode = 0;
+    *ppNode = 0;
   }
 
-  *ppNode = pNode;
-  rc = sqlite3_reset(pRtree->pReadNode);
-
-  if( rc==SQLITE_OK && iNode==1 ){
-    pRtree->iDepth = readInt16(pNode->zData);
-  }
-
-  assert( (rc==SQLITE_OK && pNode) || (pNode==0 && rc!=SQLITE_OK) );
-  nodeHashInsert(pRtree, pNode);
-
   return rc;
 }
 
@@ -99765,8 +132821,7 @@ nodeInsertCell(
   nMaxCell = (pRtree->iNodeSize-4)/pRtree->nBytesPerCell;
   nCell = NCELL(pNode);
 
-  assert(nCell<=nMaxCell);
-
+  assert( nCell<=nMaxCell );
   if( nCell<nMaxCell ){
     nodeOverwriteCell(pRtree, pNode, pCell, nCell);
     writeInt16(&pNode->zData[2], nCell+1);
@@ -99986,6 +133041,25 @@ static int rtreeOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
   return rc;
 }
 
+
+/*
+** Free the RtreeCursor.aConstraint[] array and its contents.
+*/
+static void freeCursorConstraints(RtreeCursor *pCsr){
+  if( pCsr->aConstraint ){
+    int i;                        /* Used to iterate through constraint array */
+    for(i=0; i<pCsr->nConstraint; i++){
+      sqlite3_rtree_geometry *pGeom = pCsr->aConstraint[i].pGeom;
+      if( pGeom ){
+        if( pGeom->xDelUser ) pGeom->xDelUser(pGeom->pUser);
+        sqlite3_free(pGeom);
+      }
+    }
+    sqlite3_free(pCsr->aConstraint);
+    pCsr->aConstraint = 0;
+  }
+}
+
 /* 
 ** Rtree virtual table module xClose method.
 */
@@ -99993,7 +133067,7 @@ static int rtreeClose(sqlite3_vtab_cursor *cur){
   Rtree *pRtree = (Rtree *)(cur->pVtab);
   int rc;
   RtreeCursor *pCsr = (RtreeCursor *)cur;
-  sqlite3_free(pCsr->aConstraint);
+  freeCursorConstraints(pCsr);
   rc = nodeRelease(pRtree, pCsr->pNode);
   sqlite3_free(pCsr);
   return rc;
@@ -100010,57 +133084,104 @@ static int rtreeEof(sqlite3_vtab_cursor *cur){
   return (pCsr->pNode==0);
 }
 
+/*
+** The r-tree constraint passed as the second argument to this function is
+** guaranteed to be a MATCH constraint.
+*/
+static int testRtreeGeom(
+  Rtree *pRtree,                  /* R-Tree object */
+  RtreeConstraint *pConstraint,   /* MATCH constraint to test */
+  RtreeCell *pCell,               /* Cell to test */
+  int *pbRes                      /* OUT: Test result */
+){
+  int i;
+  RtreeDValue aCoord[RTREE_MAX_DIMENSIONS*2];
+  int nCoord = pRtree->nDim*2;
+
+  assert( pConstraint->op==RTREE_MATCH );
+  assert( pConstraint->pGeom );
+
+  for(i=0; i<nCoord; i++){
+    aCoord[i] = DCOORD(pCell->aCoord[i]);
+  }
+  return pConstraint->xGeom(pConstraint->pGeom, nCoord, aCoord, pbRes);
+}
+
 /* 
 ** Cursor pCursor currently points to a cell in a non-leaf page.
-** Return true if the sub-tree headed by the cell is filtered
+** Set *pbEof to true if the sub-tree headed by the cell is filtered
 ** (excluded) by the constraints in the pCursor->aConstraint[] 
 ** array, or false otherwise.
+**
+** Return SQLITE_OK if successful or an SQLite error code if an error
+** occurs within a geometry callback.
 */
-static int testRtreeCell(Rtree *pRtree, RtreeCursor *pCursor){
+static int testRtreeCell(Rtree *pRtree, RtreeCursor *pCursor, int *pbEof){
   RtreeCell cell;
   int ii;
   int bRes = 0;
+  int rc = SQLITE_OK;
 
   nodeGetCell(pRtree, pCursor->pNode, pCursor->iCell, &cell);
   for(ii=0; bRes==0 && ii<pCursor->nConstraint; ii++){
     RtreeConstraint *p = &pCursor->aConstraint[ii];
-    double cell_min = DCOORD(cell.aCoord[(p->iCoord>>1)*2]);
-    double cell_max = DCOORD(cell.aCoord[(p->iCoord>>1)*2+1]);
+    RtreeDValue cell_min = DCOORD(cell.aCoord[(p->iCoord>>1)*2]);
+    RtreeDValue cell_max = DCOORD(cell.aCoord[(p->iCoord>>1)*2+1]);
 
     assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE 
-        || p->op==RTREE_GT || p->op==RTREE_EQ
+        || p->op==RTREE_GT || p->op==RTREE_EQ || p->op==RTREE_MATCH
     );
 
     switch( p->op ){
-      case RTREE_LE: case RTREE_LT: bRes = p->rValue<cell_min; break;
-      case RTREE_GE: case RTREE_GT: bRes = p->rValue>cell_max; break;
-      case RTREE_EQ: 
+      case RTREE_LE: case RTREE_LT: 
+        bRes = p->rValue<cell_min; 
+        break;
+
+      case RTREE_GE: case RTREE_GT: 
+        bRes = p->rValue>cell_max; 
+        break;
+
+      case RTREE_EQ:
         bRes = (p->rValue>cell_max || p->rValue<cell_min);
         break;
+
+      default: {
+        assert( p->op==RTREE_MATCH );
+        rc = testRtreeGeom(pRtree, p, &cell, &bRes);
+        bRes = !bRes;
+        break;
+      }
     }
   }
 
-  return bRes;
+  *pbEof = bRes;
+  return rc;
 }
 
 /* 
-** Return true if the cell that cursor pCursor currently points to
+** Test if the cell that cursor pCursor currently points to
 ** would be filtered (excluded) by the constraints in the 
-** pCursor->aConstraint[] array, or false otherwise.
+** pCursor->aConstraint[] array. If so, set *pbEof to true before
+** returning. If the cell is not filtered (excluded) by the constraints,
+** set pbEof to zero.
+**
+** Return SQLITE_OK if successful or an SQLite error code if an error
+** occurs within a geometry callback.
 **
 ** This function assumes that the cell is part of a leaf node.
 */
-static int testRtreeEntry(Rtree *pRtree, RtreeCursor *pCursor){
+static int testRtreeEntry(Rtree *pRtree, RtreeCursor *pCursor, int *pbEof){
   RtreeCell cell;
   int ii;
+  *pbEof = 0;
 
   nodeGetCell(pRtree, pCursor->pNode, pCursor->iCell, &cell);
   for(ii=0; ii<pCursor->nConstraint; ii++){
     RtreeConstraint *p = &pCursor->aConstraint[ii];
-    double coord = DCOORD(cell.aCoord[p->iCoord]);
+    RtreeDValue coord = DCOORD(cell.aCoord[p->iCoord]);
     int res;
     assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE 
-        || p->op==RTREE_GT || p->op==RTREE_EQ
+        || p->op==RTREE_GT || p->op==RTREE_EQ || p->op==RTREE_MATCH
     );
     switch( p->op ){
       case RTREE_LE: res = (coord<=p->rValue); break;
@@ -100068,12 +133189,24 @@ static int testRtreeEntry(Rtree *pRtree, RtreeCursor *pCursor){
       case RTREE_GE: res = (coord>=p->rValue); break;
       case RTREE_GT: res = (coord>p->rValue);  break;
       case RTREE_EQ: res = (coord==p->rValue); break;
+      default: {
+        int rc;
+        assert( p->op==RTREE_MATCH );
+        rc = testRtreeGeom(pRtree, p, &cell, &res);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        break;
+      }
     }
 
-    if( !res ) return 1;
+    if( !res ){
+      *pbEof = 1;
+      return SQLITE_OK;
+    }
   }
 
-  return 0;
+  return SQLITE_OK;
 }
 
 /*
@@ -100100,19 +133233,18 @@ static int descendToCell(
   assert( iHeight>=0 );
 
   if( iHeight==0 ){
-    isEof = testRtreeEntry(pRtree, pCursor);
+    rc = testRtreeEntry(pRtree, pCursor, &isEof);
   }else{
-    isEof = testRtreeCell(pRtree, pCursor);
+    rc = testRtreeCell(pRtree, pCursor, &isEof);
   }
-  if( isEof || iHeight==0 ){
-    *pEof = isEof;
-    return SQLITE_OK;
+  if( rc!=SQLITE_OK || isEof || iHeight==0 ){
+    goto descend_to_cell_out;
   }
 
   iRowid = nodeGetRowid(pRtree, pCursor->pNode, pCursor->iCell);
   rc = nodeAcquire(pRtree, iRowid, pCursor->pNode, &pChild);
   if( rc!=SQLITE_OK ){
-    return rc;
+    goto descend_to_cell_out;
   }
 
   nodeRelease(pRtree, pCursor->pNode);
@@ -100122,7 +133254,7 @@ static int descendToCell(
     pCursor->iCell = ii;
     rc = descendToCell(pRtree, pCursor, iHeight-1, &isEof);
     if( rc!=SQLITE_OK ){
-      return rc;
+      goto descend_to_cell_out;
     }
   }
 
@@ -100134,32 +133266,43 @@ static int descendToCell(
     pCursor->iCell = iSavedCell;
   }
 
+descend_to_cell_out:
   *pEof = isEof;
-  return SQLITE_OK;
+  return rc;
 }
 
 /*
 ** One of the cells in node pNode is guaranteed to have a 64-bit 
 ** integer value equal to iRowid. Return the index of this cell.
 */
-static int nodeRowidIndex(Rtree *pRtree, RtreeNode *pNode, i64 iRowid){
+static int nodeRowidIndex(
+  Rtree *pRtree, 
+  RtreeNode *pNode, 
+  i64 iRowid,
+  int *piIndex
+){
   int ii;
-  for(ii=0; nodeGetRowid(pRtree, pNode, ii)!=iRowid; ii++){
-    assert( ii<(NCELL(pNode)-1) );
+  int nCell = NCELL(pNode);
+  for(ii=0; ii<nCell; ii++){
+    if( nodeGetRowid(pRtree, pNode, ii)==iRowid ){
+      *piIndex = ii;
+      return SQLITE_OK;
+    }
   }
-  return ii;
+  return SQLITE_CORRUPT_VTAB;
 }
 
 /*
 ** Return the index of the cell containing a pointer to node pNode
 ** in its parent. If pNode is the root node, return -1.
 */
-static int nodeParentIndex(Rtree *pRtree, RtreeNode *pNode){
+static int nodeParentIndex(Rtree *pRtree, RtreeNode *pNode, int *piIndex){
   RtreeNode *pParent = pNode->pParent;
   if( pParent ){
-    return nodeRowidIndex(pRtree, pParent, pNode->iNode);
+    return nodeRowidIndex(pRtree, pParent, pNode->iNode, piIndex);
   }
-  return -1;
+  *piIndex = -1;
+  return SQLITE_OK;
 }
 
 /* 
@@ -100170,13 +133313,17 @@ static int rtreeNext(sqlite3_vtab_cursor *pVtabCursor){
   RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
   int rc = SQLITE_OK;
 
+  /* RtreeCursor.pNode must not be NULL. If is is NULL, then this cursor is
+  ** already at EOF. It is against the rules to call the xNext() method of
+  ** a cursor that has already reached EOF.
+  */
+  assert( pCsr->pNode );
+
   if( pCsr->iStrategy==1 ){
     /* This "scan" is a direct lookup by rowid. There is no next entry. */
     nodeRelease(pRtree, pCsr->pNode);
     pCsr->pNode = 0;
-  }
-
-  else if( pCsr->pNode ){
+  }else{
     /* Move to the next entry that matches the configured constraints. */
     int iHeight = 0;
     while( pCsr->pNode ){
@@ -100190,7 +133337,10 @@ static int rtreeNext(sqlite3_vtab_cursor *pVtabCursor){
         }
       }
       pCsr->pNode = pNode->pParent;
-      pCsr->iCell = nodeParentIndex(pRtree, pNode);
+      rc = nodeParentIndex(pRtree, pNode, &pCsr->iCell);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
       nodeReference(pCsr->pNode);
       nodeRelease(pRtree, pNode);
       iHeight++;
@@ -100226,9 +133376,12 @@ static int rtreeColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
   }else{
     RtreeCoord c;
     nodeGetCoord(pRtree, pCsr->pNode, pCsr->iCell, i-1, &c);
+#ifndef SQLITE_RTREE_INT_ONLY
     if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
       sqlite3_result_double(ctx, c.f);
-    }else{
+    }else
+#endif
+    {
       assert( pRtree->eCoordType==RTREE_COORD_INT32 );
       sqlite3_result_int(ctx, c.i);
     }
@@ -100258,6 +133411,51 @@ static int findLeafNode(Rtree *pRtree, i64 iRowid, RtreeNode **ppLeaf){
   return rc;
 }
 
+/*
+** This function is called to configure the RtreeConstraint object passed
+** as the second argument for a MATCH constraint. The value passed as the
+** first argument to this function is the right-hand operand to the MATCH
+** operator.
+*/
+static int deserializeGeometry(sqlite3_value *pValue, RtreeConstraint *pCons){
+  RtreeMatchArg *p;
+  sqlite3_rtree_geometry *pGeom;
+  int nBlob;
+
+  /* Check that value is actually a blob. */
+  if( sqlite3_value_type(pValue)!=SQLITE_BLOB ) return SQLITE_ERROR;
+
+  /* Check that the blob is roughly the right size. */
+  nBlob = sqlite3_value_bytes(pValue);
+  if( nBlob<(int)sizeof(RtreeMatchArg) 
+   || ((nBlob-sizeof(RtreeMatchArg))%sizeof(RtreeDValue))!=0
+  ){
+    return SQLITE_ERROR;
+  }
+
+  pGeom = (sqlite3_rtree_geometry *)sqlite3_malloc(
+      sizeof(sqlite3_rtree_geometry) + nBlob
+  );
+  if( !pGeom ) return SQLITE_NOMEM;
+  memset(pGeom, 0, sizeof(sqlite3_rtree_geometry));
+  p = (RtreeMatchArg *)&pGeom[1];
+
+  memcpy(p, sqlite3_value_blob(pValue), nBlob);
+  if( p->magic!=RTREE_GEOMETRY_MAGIC 
+   || nBlob!=(int)(sizeof(RtreeMatchArg) + (p->nParam-1)*sizeof(RtreeDValue))
+  ){
+    sqlite3_free(pGeom);
+    return SQLITE_ERROR;
+  }
+
+  pGeom->pContext = p->pContext;
+  pGeom->nParam = p->nParam;
+  pGeom->aParam = p->aParam;
+
+  pCons->xGeom = p->xGeom;
+  pCons->pGeom = pGeom;
+  return SQLITE_OK;
+}
 
 /* 
 ** Rtree virtual table module xFilter method.
@@ -100276,8 +133474,7 @@ static int rtreeFilter(
 
   rtreeReference(pRtree);
 
-  sqlite3_free(pCsr->aConstraint);
-  pCsr->aConstraint = 0;
+  freeCursorConstraints(pCsr);
   pCsr->iStrategy = idxNum;
 
   if( idxNum==1 ){
@@ -100286,8 +133483,9 @@ static int rtreeFilter(
     i64 iRowid = sqlite3_value_int64(argv[0]);
     rc = findLeafNode(pRtree, iRowid, &pLeaf);
     pCsr->pNode = pLeaf; 
-    if( pLeaf && rc==SQLITE_OK ){
-      pCsr->iCell = nodeRowidIndex(pRtree, pLeaf, iRowid);
+    if( pLeaf ){
+      assert( rc==SQLITE_OK );
+      rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &pCsr->iCell);
     }
   }else{
     /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array 
@@ -100299,12 +133497,29 @@ static int rtreeFilter(
       if( !pCsr->aConstraint ){
         rc = SQLITE_NOMEM;
       }else{
-        assert( (idxStr==0 && argc==0) || strlen(idxStr)==argc*2 );
+        memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*argc);
+        assert( (idxStr==0 && argc==0)
+                || (idxStr && (int)strlen(idxStr)==argc*2) );
         for(ii=0; ii<argc; ii++){
           RtreeConstraint *p = &pCsr->aConstraint[ii];
           p->op = idxStr[ii*2];
           p->iCoord = idxStr[ii*2+1]-'a';
-          p->rValue = sqlite3_value_double(argv[ii]);
+          if( p->op==RTREE_MATCH ){
+            /* A MATCH operator. The right-hand-side must be a blob that
+            ** can be cast into an RtreeMatchArg object. One created using
+            ** an sqlite3_rtree_geometry_callback() SQL user function.
+            */
+            rc = deserializeGeometry(argv[ii], p);
+            if( rc!=SQLITE_OK ){
+              break;
+            }
+          }else{
+#ifdef SQLITE_RTREE_INT_ONLY
+            p->rValue = sqlite3_value_int64(argv[ii]);
+#else
+            p->rValue = sqlite3_value_double(argv[ii]);
+#endif
+          }
         }
       }
     }
@@ -100345,11 +133560,10 @@ static int rtreeFilter(
 **   idxNum     idxStr        Strategy
 **   ------------------------------------------------
 **     1        Unused        Direct lookup by rowid.
-**     2        See below     R-tree query.
-**     3        Unused        Full table scan.
+**     2        See below     R-tree query or full-table scan.
 **   ------------------------------------------------
 **
-** If strategy 1 or 3 is used, then idxStr is not meaningful. If strategy
+** If strategy 1 is used, then idxStr is not meaningful. If strategy
 ** 2 is used, idxStr is formatted to contain 2 bytes for each 
 ** constraint used. The first two bytes of idxStr correspond to 
 ** the constraint in sqlite3_index_info.aConstraintUsage[] with
@@ -100365,6 +133579,7 @@ static int rtreeFilter(
 **      <        0x43 ('C')
 **     >=        0x44 ('D')
 **      >        0x45 ('E')
+**   MATCH       0x46 ('F')
 **   ----------------------
 **
 ** The second of each pair of bytes identifies the coordinate column
@@ -100373,14 +133588,15 @@ static int rtreeFilter(
 */
 static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
   int rc = SQLITE_OK;
-  int ii, cCol;
+  int ii;
 
   int iIdx = 0;
   char zIdxStr[RTREE_MAX_DIMENSIONS*8+1];
   memset(zIdxStr, 0, sizeof(zIdxStr));
+  UNUSED_PARAMETER(tab);
 
   assert( pIdxInfo->idxStr==0 );
-  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
+  for(ii=0; ii<pIdxInfo->nConstraint && iIdx<(int)(sizeof(zIdxStr)-1); ii++){
     struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
 
     if( p->usable && p->iColumn==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
@@ -100403,48 +133619,23 @@ static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
       return SQLITE_OK;
     }
 
-    if( p->usable && p->iColumn>0 ){
-      u8 op = 0;
+    if( p->usable && (p->iColumn>0 || p->op==SQLITE_INDEX_CONSTRAINT_MATCH) ){
+      u8 op;
       switch( p->op ){
         case SQLITE_INDEX_CONSTRAINT_EQ: op = RTREE_EQ; break;
         case SQLITE_INDEX_CONSTRAINT_GT: op = RTREE_GT; break;
         case SQLITE_INDEX_CONSTRAINT_LE: op = RTREE_LE; break;
         case SQLITE_INDEX_CONSTRAINT_LT: op = RTREE_LT; break;
         case SQLITE_INDEX_CONSTRAINT_GE: op = RTREE_GE; break;
+        default:
+          assert( p->op==SQLITE_INDEX_CONSTRAINT_MATCH );
+          op = RTREE_MATCH; 
+          break;
       }
-      if( op ){
-        /* Make sure this particular constraint has not been used before.
-        ** If it has been used before, ignore it.
-        **
-        ** A <= or < can be used if there is a prior >= or >.
-        ** A >= or > can be used if there is a prior < or <=.
-        ** A <= or < is disqualified if there is a prior <=, <, or ==.
-        ** A >= or > is disqualified if there is a prior >=, >, or ==.
-        ** A == is disqualifed if there is any prior constraint.
-        */
-        int j, opmsk;
-        static const unsigned char compatible[] = { 0, 0, 1, 1, 2, 2 };
-        assert( compatible[RTREE_EQ & 7]==0 );
-        assert( compatible[RTREE_LT & 7]==1 );
-        assert( compatible[RTREE_LE & 7]==1 );
-        assert( compatible[RTREE_GT & 7]==2 );
-        assert( compatible[RTREE_GE & 7]==2 );
-        cCol = p->iColumn - 1 + 'a';
-        opmsk = compatible[op & 7];
-        for(j=0; j<iIdx; j+=2){
-          if( zIdxStr[j+1]==cCol && (compatible[zIdxStr[j] & 7] & opmsk)!=0 ){
-            op = 0;
-            break;
-          }
-        }
-      }
-      if( op ){
-        assert( iIdx<sizeof(zIdxStr)-1 );
-        zIdxStr[iIdx++] = op;
-        zIdxStr[iIdx++] = cCol;
-        pIdxInfo->aConstraintUsage[ii].argvIndex = (iIdx/2);
-        pIdxInfo->aConstraintUsage[ii].omit = 1;
-      }
+      zIdxStr[iIdx++] = op;
+      zIdxStr[iIdx++] = p->iColumn - 1 + 'a';
+      pIdxInfo->aConstraintUsage[ii].argvIndex = (iIdx/2);
+      pIdxInfo->aConstraintUsage[ii].omit = 1;
     }
   }
 
@@ -100461,11 +133652,11 @@ static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
 /*
 ** Return the N-dimensional volumn of the cell stored in *p.
 */
-static float cellArea(Rtree *pRtree, RtreeCell *p){
-  float area = 1.0;
+static RtreeDValue cellArea(Rtree *pRtree, RtreeCell *p){
+  RtreeDValue area = (RtreeDValue)1;
   int ii;
   for(ii=0; ii<(pRtree->nDim*2); ii+=2){
-    area = area * (DCOORD(p->aCoord[ii+1]) - DCOORD(p->aCoord[ii]));
+    area = (area * (DCOORD(p->aCoord[ii+1]) - DCOORD(p->aCoord[ii])));
   }
   return area;
 }
@@ -100474,8 +133665,8 @@ static float cellArea(Rtree *pRtree, RtreeCell *p){
 ** Return the margin length of cell p. The margin length is the sum
 ** of the objects size in each dimension.
 */
-static float cellMargin(Rtree *pRtree, RtreeCell *p){
-  float margin = 0.0;
+static RtreeDValue cellMargin(Rtree *pRtree, RtreeCell *p){
+  RtreeDValue margin = (RtreeDValue)0;
   int ii;
   for(ii=0; ii<(pRtree->nDim*2); ii+=2){
     margin += (DCOORD(p->aCoord[ii+1]) - DCOORD(p->aCoord[ii]));
@@ -100523,8 +133714,8 @@ static int cellContains(Rtree *pRtree, RtreeCell *p1, RtreeCell *p2){
 /*
 ** Return the amount cell p would grow by if it were unioned with pCell.
 */
-static float cellGrowth(Rtree *pRtree, RtreeCell *p, RtreeCell *pCell){
-  float area;
+static RtreeDValue cellGrowth(Rtree *pRtree, RtreeCell *p, RtreeCell *pCell){
+  RtreeDValue area;
   RtreeCell cell;
   memcpy(&cell, p, sizeof(RtreeCell));
   area = cellArea(pRtree, &cell);
@@ -100533,7 +133724,7 @@ static float cellGrowth(Rtree *pRtree, RtreeCell *p, RtreeCell *pCell){
 }
 
 #if VARIANT_RSTARTREE_CHOOSESUBTREE || VARIANT_RSTARTREE_SPLIT
-static float cellOverlap(
+static RtreeDValue cellOverlap(
   Rtree *pRtree, 
   RtreeCell *p, 
   RtreeCell *aCell, 
@@ -100541,14 +133732,19 @@ static float cellOverlap(
   int iExclude
 ){
   int ii;
-  float overlap = 0.0;
+  RtreeDValue overlap = 0.0;
   for(ii=0; ii<nCell; ii++){
-    if( ii!=iExclude ){
+#if VARIANT_RSTARTREE_CHOOSESUBTREE
+    if( ii!=iExclude )
+#else
+    assert( iExclude==-1 );
+    UNUSED_PARAMETER(iExclude);
+#endif
+    {
       int jj;
-      float o = 1.0;
+      RtreeDValue o = (RtreeDValue)1;
       for(jj=0; jj<(pRtree->nDim*2); jj+=2){
-        double x1;
-        double x2;
+        RtreeDValue x1, x2;
 
         x1 = MAX(DCOORD(p->aCoord[jj]), DCOORD(aCell[ii].aCoord[jj]));
         x2 = MIN(DCOORD(p->aCoord[jj+1]), DCOORD(aCell[ii].aCoord[jj+1]));
@@ -100568,7 +133764,7 @@ static float cellOverlap(
 #endif
 
 #if VARIANT_RSTARTREE_CHOOSESUBTREE
-static float cellOverlapEnlargement(
+static RtreeDValue cellOverlapEnlargement(
   Rtree *pRtree, 
   RtreeCell *p, 
   RtreeCell *pInsert, 
@@ -100576,12 +133772,11 @@ static float cellOverlapEnlargement(
   int nCell, 
   int iExclude
 ){
-  float before;
-  float after;
+  RtreeDValue before, after;
   before = cellOverlap(pRtree, p, aCell, nCell, iExclude);
   cellUnion(pRtree, p, pInsert);
   after = cellOverlap(pRtree, p, aCell, nCell, iExclude);
-  return after-before;
+  return (after-before);
 }
 #endif
 
@@ -100603,11 +133798,14 @@ static int ChooseLeaf(
 
   for(ii=0; rc==SQLITE_OK && ii<(pRtree->iDepth-iHeight); ii++){
     int iCell;
-    sqlite3_int64 iBest;
+    sqlite3_int64 iBest = 0;
 
-    float fMinGrowth;
-    float fMinArea;
-    float fMinOverlap;
+    RtreeDValue fMinGrowth = 0.0;
+    RtreeDValue fMinArea = 0.0;
+#if VARIANT_RSTARTREE_CHOOSESUBTREE
+    RtreeDValue fMinOverlap = 0.0;
+    RtreeDValue overlap;
+#endif
 
     int nCell = NCELL(pNode);
     RtreeCell cell;
@@ -100636,23 +133834,33 @@ static int ChooseLeaf(
     ** the smallest area.
     */
     for(iCell=0; iCell<nCell; iCell++){
-      float growth;
-      float area;
-      float overlap = 0.0;
+      int bBest = 0;
+      RtreeDValue growth;
+      RtreeDValue area;
       nodeGetCell(pRtree, pNode, iCell, &cell);
       growth = cellGrowth(pRtree, &cell, pCell);
       area = cellArea(pRtree, &cell);
+
 #if VARIANT_RSTARTREE_CHOOSESUBTREE
       if( ii==(pRtree->iDepth-1) ){
         overlap = cellOverlapEnlargement(pRtree,&cell,pCell,aCell,nCell,iCell);
+      }else{
+        overlap = 0.0;
       }
-#endif
       if( (iCell==0) 
        || (overlap<fMinOverlap) 
        || (overlap==fMinOverlap && growth<fMinGrowth)
        || (overlap==fMinOverlap && growth==fMinGrowth && area<fMinArea)
       ){
+        bBest = 1;
         fMinOverlap = overlap;
+      }
+#else
+      if( iCell==0||growth<fMinGrowth||(growth==fMinGrowth && area<fMinArea) ){
+        bBest = 1;
+      }
+#endif
+      if( bBest ){
         fMinGrowth = growth;
         fMinArea = area;
         iBest = cell.iRowid;
@@ -100674,16 +133882,20 @@ static int ChooseLeaf(
 ** the node pNode. This function updates the bounding box cells in
 ** all ancestor elements.
 */
-static void AdjustTree(
+static int AdjustTree(
   Rtree *pRtree,                    /* Rtree table */
   RtreeNode *pNode,                 /* Adjust ancestry of this node. */
   RtreeCell *pCell                  /* This cell was just inserted */
 ){
   RtreeNode *p = pNode;
   while( p->pParent ){
-    RtreeCell cell;
     RtreeNode *pParent = p->pParent;
-    int iCell = nodeParentIndex(pRtree, p);
+    RtreeCell cell;
+    int iCell;
+
+    if( nodeParentIndex(pRtree, p, &iCell) ){
+      return SQLITE_CORRUPT_VTAB;
+    }
 
     nodeGetCell(pRtree, pParent, iCell, &cell);
     if( !cellContains(pRtree, &cell, pCell) ){
@@ -100693,6 +133905,7 @@ static void AdjustTree(
  
     p = pParent;
   }
+  return SQLITE_OK;
 }
 
 /*
@@ -100750,7 +133963,7 @@ static void LinearPickSeeds(
   int i;
   int iLeftSeed = 0;
   int iRightSeed = 1;
-  float maxNormalInnerWidth = 0.0;
+  RtreeDValue maxNormalInnerWidth = (RtreeDValue)0;
 
   /* Pick two "seed" cells from the array of cells. The algorithm used
   ** here is the LinearPickSeeds algorithm from Gutman[1984]. The 
@@ -100758,18 +133971,18 @@ static void LinearPickSeeds(
   ** variables iLeftSeek and iRightSeed.
   */
   for(i=0; i<pRtree->nDim; i++){
-    float x1 = aCell[0].aCoord[i*2];
-    float x2 = aCell[0].aCoord[i*2+1];
-    float x3 = x1;
-    float x4 = x2;
+    RtreeDValue x1 = DCOORD(aCell[0].aCoord[i*2]);
+    RtreeDValue x2 = DCOORD(aCell[0].aCoord[i*2+1]);
+    RtreeDValue x3 = x1;
+    RtreeDValue x4 = x2;
     int jj;
 
     int iCellLeft = 0;
     int iCellRight = 0;
 
     for(jj=1; jj<nCell; jj++){
-      float left = aCell[jj].aCoord[i*2];
-      float right = aCell[jj].aCoord[i*2+1];
+      RtreeDValue left = DCOORD(aCell[jj].aCoord[i*2]);
+      RtreeDValue right = DCOORD(aCell[jj].aCoord[i*2+1]);
 
       if( left<x1 ) x1 = left;
       if( right>x4 ) x4 = right;
@@ -100784,7 +133997,7 @@ static void LinearPickSeeds(
     }
 
     if( x4!=x1 ){
-      float normalwidth = (x3 - x2) / (x4 - x1);
+      RtreeDValue normalwidth = (x3 - x2) / (x4 - x1);
       if( normalwidth>maxNormalInnerWidth ){
         iLeftSeed = iCellLeft;
         iRightSeed = iCellRight;
@@ -100813,13 +134026,13 @@ static RtreeCell *QuadraticPickNext(
   #define FABS(a) ((a)<0.0?-1.0*(a):(a))
 
   int iSelect = -1;
-  float fDiff;
+  RtreeDValue fDiff;
   int ii;
   for(ii=0; ii<nCell; ii++){
     if( aiUsed[ii]==0 ){
-      float left = cellGrowth(pRtree, pLeftBox, &aCell[ii]);
-      float right = cellGrowth(pRtree, pLeftBox, &aCell[ii]);
-      float diff = FABS(right-left);
+      RtreeDValue left = cellGrowth(pRtree, pLeftBox, &aCell[ii]);
+      RtreeDValue right = cellGrowth(pRtree, pLeftBox, &aCell[ii]);
+      RtreeDValue diff = FABS(right-left);
       if( iSelect<0 || diff>fDiff ){
         fDiff = diff;
         iSelect = ii;
@@ -100846,13 +134059,13 @@ static void QuadraticPickSeeds(
 
   int iLeftSeed = 0;
   int iRightSeed = 1;
-  float fWaste = 0.0;
+  RtreeDValue fWaste = 0.0;
 
   for(ii=0; ii<nCell; ii++){
     for(jj=ii+1; jj<nCell; jj++){
-      float right = cellArea(pRtree, &aCell[jj]);
-      float growth = cellGrowth(pRtree, &aCell[ii], &aCell[jj]);
-      float waste = growth - right;
+      RtreeDValue right = cellArea(pRtree, &aCell[jj]);
+      RtreeDValue growth = cellGrowth(pRtree, &aCell[ii], &aCell[jj]);
+      RtreeDValue waste = growth - right;
 
       if( waste>fWaste ){
         iLeftSeed = ii;
@@ -100887,7 +134100,7 @@ static void QuadraticPickSeeds(
 static void SortByDistance(
   int *aIdx, 
   int nIdx, 
-  float *aDistance, 
+  RtreeDValue *aDistance, 
   int *aSpare
 ){
   if( nIdx>1 ){
@@ -100913,8 +134126,8 @@ static void SortByDistance(
         aIdx[iLeft+iRight] = aLeft[iLeft];
         iLeft++;
       }else{
-        float fLeft = aDistance[aLeft[iLeft]];
-        float fRight = aDistance[aRight[iRight]];
+        RtreeDValue fLeft = aDistance[aLeft[iLeft]];
+        RtreeDValue fRight = aDistance[aRight[iRight]];
         if( fLeft<fRight ){
           aIdx[iLeft+iRight] = aLeft[iLeft];
           iLeft++;
@@ -100930,8 +134143,8 @@ static void SortByDistance(
     {
       int jj;
       for(jj=1; jj<nIdx; jj++){
-        float left = aDistance[aIdx[jj-1]];
-        float right = aDistance[aIdx[jj]];
+        RtreeDValue left = aDistance[aIdx[jj-1]];
+        RtreeDValue right = aDistance[aIdx[jj]];
         assert( left<=right );
       }
     }
@@ -100974,10 +134187,10 @@ static void SortByDimension(
     memcpy(aSpare, aLeft, sizeof(int)*nLeft);
     aLeft = aSpare;
     while( iLeft<nLeft || iRight<nRight ){
-      double xleft1 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2]);
-      double xleft2 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2+1]);
-      double xright1 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2]);
-      double xright2 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2+1]);
+      RtreeDValue xleft1 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2]);
+      RtreeDValue xleft2 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2+1]);
+      RtreeDValue xright1 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2]);
+      RtreeDValue xright2 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2+1]);
       if( (iLeft!=nLeft) && ((iRight==nRight)
        || (xleft1<xright1)
        || (xleft1==xright1 && xleft2<xright2)
@@ -100995,10 +134208,10 @@ static void SortByDimension(
     {
       int jj;
       for(jj=1; jj<nIdx; jj++){
-        float xleft1 = aCell[aIdx[jj-1]].aCoord[iDim*2];
-        float xleft2 = aCell[aIdx[jj-1]].aCoord[iDim*2+1];
-        float xright1 = aCell[aIdx[jj]].aCoord[iDim*2];
-        float xright2 = aCell[aIdx[jj]].aCoord[iDim*2+1];
+        RtreeDValue xleft1 = aCell[aIdx[jj-1]].aCoord[iDim*2];
+        RtreeDValue xleft2 = aCell[aIdx[jj-1]].aCoord[iDim*2+1];
+        RtreeDValue xright1 = aCell[aIdx[jj]].aCoord[iDim*2];
+        RtreeDValue xright2 = aCell[aIdx[jj]].aCoord[iDim*2+1];
         assert( xleft1<=xright1 && (xleft1<xright1 || xleft2<=xright2) );
       }
     }
@@ -101023,9 +134236,9 @@ static int splitNodeStartree(
   int *aSpare;
   int ii;
 
-  int iBestDim;
-  int iBestSplit;
-  float fBestMargin;
+  int iBestDim = 0;
+  int iBestSplit = 0;
+  RtreeDValue fBestMargin = 0.0;
 
   int nByte = (pRtree->nDim+1)*(sizeof(int*)+nCell*sizeof(int));
 
@@ -101046,10 +134259,10 @@ static int splitNodeStartree(
   }
 
   for(ii=0; ii<pRtree->nDim; ii++){
-    float margin = 0.0;
-    float fBestOverlap;
-    float fBestArea;
-    int iBestLeft;
+    RtreeDValue margin = 0.0;
+    RtreeDValue fBestOverlap = 0.0;
+    RtreeDValue fBestArea = 0.0;
+    int iBestLeft = 0;
     int nLeft;
 
     for(
@@ -101060,8 +134273,8 @@ static int splitNodeStartree(
       RtreeCell left;
       RtreeCell right;
       int kk;
-      float overlap;
-      float area;
+      RtreeDValue overlap;
+      RtreeDValue area;
 
       memcpy(&left, &aCell[aaSorted[ii][0]], sizeof(RtreeCell));
       memcpy(&right, &aCell[aaSorted[ii][nCell-1]], sizeof(RtreeCell));
@@ -101127,6 +134340,9 @@ static int splitNodeGuttman(
   int i;
 
   aiUsed = sqlite3_malloc(sizeof(int)*nCell);
+  if( !aiUsed ){
+    return SQLITE_NOMEM;
+  }
   memset(aiUsed, 0, sizeof(int)*nCell);
 
   PickSeeds(pRtree, aCell, nCell, &iLeftSeed, &iRightSeed);
@@ -101141,7 +134357,7 @@ static int splitNodeGuttman(
   for(i=nCell-2; i>0; i--){
     RtreeCell *pNext;
     pNext = PickNext(pRtree, aCell, nCell, pBboxLeft, pBboxRight, aiUsed);
-    float diff =  
+    RtreeDValue diff =  
       cellGrowth(pRtree, pBboxLeft, pNext) - 
       cellGrowth(pRtree, pBboxRight, pNext)
     ;
@@ -101218,14 +134434,14 @@ static int SplitNode(
   nCell++;
 
   if( pNode->iNode==1 ){
-    pRight = nodeNew(pRtree, pNode, 1);
-    pLeft = nodeNew(pRtree, pNode, 1);
+    pRight = nodeNew(pRtree, pNode);
+    pLeft = nodeNew(pRtree, pNode);
     pRtree->iDepth++;
     pNode->isDirty = 1;
     writeInt16(pNode->zData, pRtree->iDepth);
   }else{
     pLeft = pNode;
-    pRight = nodeNew(pRtree, pLeft->pParent, 1);
+    pRight = nodeNew(pRtree, pLeft->pParent);
     nodeReference(pLeft);
   }
 
@@ -101242,8 +134458,12 @@ static int SplitNode(
     goto splitnode_out;
   }
 
-  /* Ensure both child nodes have node numbers assigned to them. */
-  if( (0==pRight->iNode && SQLITE_OK!=(rc = nodeWrite(pRtree, pRight)))
+  /* Ensure both child nodes have node numbers assigned to them by calling
+  ** nodeWrite(). Node pRight always needs a node number, as it was created
+  ** by nodeNew() above. But node pLeft sometimes already has a node number.
+  ** In this case avoid the all to nodeWrite().
+  */
+  if( SQLITE_OK!=(rc = nodeWrite(pRtree, pRight))
    || (0==pLeft->iNode && SQLITE_OK!=(rc = nodeWrite(pRtree, pLeft)))
   ){
     goto splitnode_out;
@@ -101259,9 +134479,15 @@ static int SplitNode(
     }
   }else{
     RtreeNode *pParent = pLeft->pParent;
-    int iCell = nodeParentIndex(pRtree, pLeft);
-    nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell);
-    AdjustTree(pRtree, pParent, &leftbbox);
+    int iCell;
+    rc = nodeParentIndex(pRtree, pLeft, &iCell);
+    if( rc==SQLITE_OK ){
+      nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell);
+      rc = AdjustTree(pRtree, pParent, &leftbbox);
+    }
+    if( rc!=SQLITE_OK ){
+      goto splitnode_out;
+    }
   }
   if( (rc = rtreeInsertCell(pRtree, pRight->pParent, &rightbbox, iHeight+1)) ){
     goto splitnode_out;
@@ -101305,20 +134531,43 @@ splitnode_out:
   return rc;
 }
 
+/*
+** If node pLeaf is not the root of the r-tree and its pParent pointer is 
+** still NULL, load all ancestor nodes of pLeaf into memory and populate
+** the pLeaf->pParent chain all the way up to the root node.
+**
+** This operation is required when a row is deleted (or updated - an update
+** is implemented as a delete followed by an insert). SQLite provides the
+** rowid of the row to delete, which can be used to find the leaf on which
+** the entry resides (argument pLeaf). Once the leaf is located, this 
+** function is called to determine its ancestry.
+*/
 static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){
   int rc = SQLITE_OK;
-  if( pLeaf->iNode!=1 && pLeaf->pParent==0 ){
-    sqlite3_bind_int64(pRtree->pReadParent, 1, pLeaf->iNode);
-    if( sqlite3_step(pRtree->pReadParent)==SQLITE_ROW ){
-      i64 iNode = sqlite3_column_int64(pRtree->pReadParent, 0);
-      rc = nodeAcquire(pRtree, iNode, 0, &pLeaf->pParent);
-    }else{
-      rc = SQLITE_ERROR;
-    }
-    sqlite3_reset(pRtree->pReadParent);
-    if( rc==SQLITE_OK ){
-      rc = fixLeafParent(pRtree, pLeaf->pParent);
+  RtreeNode *pChild = pLeaf;
+  while( rc==SQLITE_OK && pChild->iNode!=1 && pChild->pParent==0 ){
+    int rc2 = SQLITE_OK;          /* sqlite3_reset() return code */
+    sqlite3_bind_int64(pRtree->pReadParent, 1, pChild->iNode);
+    rc = sqlite3_step(pRtree->pReadParent);
+    if( rc==SQLITE_ROW ){
+      RtreeNode *pTest;           /* Used to test for reference loops */
+      i64 iNode;                  /* Node number of parent node */
+
+      /* Before setting pChild->pParent, test that we are not creating a
+      ** loop of references (as we would if, say, pChild==pParent). We don't
+      ** want to do this as it leads to a memory leak when trying to delete
+      ** the referenced counted node structures.
+      */
+      iNode = sqlite3_column_int64(pRtree->pReadParent, 0);
+      for(pTest=pLeaf; pTest && pTest->iNode!=iNode; pTest=pTest->pParent);
+      if( !pTest ){
+        rc2 = nodeAcquire(pRtree, iNode, 0, &pChild->pParent);
+      }
     }
+    rc = sqlite3_reset(pRtree->pReadParent);
+    if( rc==SQLITE_OK ) rc = rc2;
+    if( rc==SQLITE_OK && !pChild->pParent ) rc = SQLITE_CORRUPT_VTAB;
+    pChild = pChild->pParent;
   }
   return rc;
 }
@@ -101327,18 +134576,24 @@ static int deleteCell(Rtree *, RtreeNode *, int, int);
 
 static int removeNode(Rtree *pRtree, RtreeNode *pNode, int iHeight){
   int rc;
-  RtreeNode *pParent;
+  int rc2;
+  RtreeNode *pParent = 0;
   int iCell;
 
   assert( pNode->nRef==1 );
 
   /* Remove the entry in the parent cell. */
-  iCell = nodeParentIndex(pRtree, pNode);
-  pParent = pNode->pParent;
-  pNode->pParent = 0;
-  if( SQLITE_OK!=(rc = deleteCell(pRtree, pParent, iCell, iHeight+1)) 
-   || SQLITE_OK!=(rc = nodeRelease(pRtree, pParent))
-  ){
+  rc = nodeParentIndex(pRtree, pNode, &iCell);
+  if( rc==SQLITE_OK ){
+    pParent = pNode->pParent;
+    pNode->pParent = 0;
+    rc = deleteCell(pRtree, pParent, iCell, iHeight+1);
+  }
+  rc2 = nodeRelease(pRtree, pParent);
+  if( rc==SQLITE_OK ){
+    rc = rc2;
+  }
+  if( rc!=SQLITE_OK ){
     return rc;
   }
 
@@ -101368,8 +134623,9 @@ static int removeNode(Rtree *pRtree, RtreeNode *pNode, int iHeight){
   return SQLITE_OK;
 }
 
-static void fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
+static int fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
   RtreeNode *pParent = pNode->pParent;
+  int rc = SQLITE_OK; 
   if( pParent ){
     int ii; 
     int nCell = NCELL(pNode);
@@ -101381,10 +134637,13 @@ static void fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
       cellUnion(pRtree, &box, &cell);
     }
     box.iRowid = pNode->iNode;
-    ii = nodeParentIndex(pRtree, pNode);
-    nodeOverwriteCell(pRtree, pParent, &box, ii);
-    fixBoundingBox(pRtree, pParent);
+    rc = nodeParentIndex(pRtree, pNode, &ii);
+    if( rc==SQLITE_OK ){
+      nodeOverwriteCell(pRtree, pParent, &box, ii);
+      rc = fixBoundingBox(pRtree, pParent);
+    }
   }
+  return rc;
 }
 
 /*
@@ -101392,6 +134651,7 @@ static void fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
 ** cell, adjust the r-tree data structure if required.
 */
 static int deleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell, int iHeight){
+  RtreeNode *pParent;
   int rc;
 
   if( SQLITE_OK!=(rc = fixLeafParent(pRtree, pNode)) ){
@@ -101408,14 +134668,13 @@ static int deleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell, int iHeight){
   ** cell in the parent node so that it tightly contains the updated
   ** node.
   */
-  if( pNode->iNode!=1 ){
-    RtreeNode *pParent = pNode->pParent;
-    if( (pParent->iNode!=1 || NCELL(pParent)!=1) 
-     && (NCELL(pNode)<RTREE_MINCELLS(pRtree))
-    ){
+  pParent = pNode->pParent;
+  assert( pParent || pNode->iNode==1 );
+  if( pParent ){
+    if( NCELL(pNode)<RTREE_MINCELLS(pRtree) ){
       rc = removeNode(pRtree, pNode, iHeight);
     }else{
-      fixBoundingBox(pRtree, pNode);
+      rc = fixBoundingBox(pRtree, pNode);
     }
   }
 
@@ -101431,32 +134690,34 @@ static int Reinsert(
   int *aOrder;
   int *aSpare;
   RtreeCell *aCell;
-  float *aDistance;
+  RtreeDValue *aDistance;
   int nCell;
-  float aCenterCoord[RTREE_MAX_DIMENSIONS];
+  RtreeDValue aCenterCoord[RTREE_MAX_DIMENSIONS];
   int iDim;
   int ii;
   int rc = SQLITE_OK;
+  int n;
 
-  memset(aCenterCoord, 0, sizeof(float)*RTREE_MAX_DIMENSIONS);
+  memset(aCenterCoord, 0, sizeof(RtreeDValue)*RTREE_MAX_DIMENSIONS);
 
   nCell = NCELL(pNode)+1;
+  n = (nCell+1)&(~1);
 
   /* Allocate the buffers used by this operation. The allocation is
   ** relinquished before this function returns.
   */
-  aCell = (RtreeCell *)sqlite3_malloc(nCell * (
-    sizeof(RtreeCell) +         /* aCell array */
-    sizeof(int)       +         /* aOrder array */
-    sizeof(int)       +         /* aSpare array */
-    sizeof(float)               /* aDistance array */
+  aCell = (RtreeCell *)sqlite3_malloc(n * (
+    sizeof(RtreeCell)     +         /* aCell array */
+    sizeof(int)           +         /* aOrder array */
+    sizeof(int)           +         /* aSpare array */
+    sizeof(RtreeDValue)             /* aDistance array */
   ));
   if( !aCell ){
     return SQLITE_NOMEM;
   }
-  aOrder    = (int *)&aCell[nCell];
-  aSpare    = (int *)&aOrder[nCell];
-  aDistance = (float *)&aSpare[nCell];
+  aOrder    = (int *)&aCell[n];
+  aSpare    = (int *)&aOrder[n];
+  aDistance = (RtreeDValue *)&aSpare[n];
 
   for(ii=0; ii<nCell; ii++){
     if( ii==(nCell-1) ){
@@ -101471,14 +134732,14 @@ static int Reinsert(
     }
   }
   for(iDim=0; iDim<pRtree->nDim; iDim++){
-    aCenterCoord[iDim] = aCenterCoord[iDim]/((float)nCell*2.0);
+    aCenterCoord[iDim] = (aCenterCoord[iDim]/(nCell*(RtreeDValue)2));
   }
 
   for(ii=0; ii<nCell; ii++){
     aDistance[ii] = 0.0;
     for(iDim=0; iDim<pRtree->nDim; iDim++){
-      float coord = DCOORD(aCell[ii].aCoord[iDim*2+1]) - 
-          DCOORD(aCell[ii].aCoord[iDim*2]);
+      RtreeDValue coord = (DCOORD(aCell[ii].aCoord[iDim*2+1]) - 
+                               DCOORD(aCell[ii].aCoord[iDim*2]));
       aDistance[ii] += (coord-aCenterCoord[iDim])*(coord-aCenterCoord[iDim]);
     }
   }
@@ -101498,7 +134759,7 @@ static int Reinsert(
     }
   }
   if( rc==SQLITE_OK ){
-    fixBoundingBox(pRtree, pNode);
+    rc = fixBoundingBox(pRtree, pNode);
   }
   for(; rc==SQLITE_OK && ii<nCell; ii++){
     /* Find a node to store this cell in. pNode->iNode currently contains
@@ -101552,11 +134813,13 @@ static int rtreeInsertCell(
     rc = SplitNode(pRtree, pNode, pCell, iHeight);
 #endif
   }else{
-    AdjustTree(pRtree, pNode, pCell);
-    if( iHeight==0 ){
-      rc = rowidWrite(pRtree, pCell->iRowid, pNode->iNode);
-    }else{
-      rc = parentWrite(pRtree, pCell->iRowid, pNode->iNode);
+    rc = AdjustTree(pRtree, pNode, pCell);
+    if( rc==SQLITE_OK ){
+      if( iHeight==0 ){
+        rc = rowidWrite(pRtree, pCell->iRowid, pNode->iNode);
+      }else{
+        rc = parentWrite(pRtree, pCell->iRowid, pNode->iNode);
+      }
     }
   }
   return rc;
@@ -101575,10 +134838,10 @@ static int reinsertNodeContent(Rtree *pRtree, RtreeNode *pNode){
     /* Find a node to store this cell in. pNode->iNode currently contains
     ** the height of the sub-tree headed by the cell.
     */
-    rc = ChooseLeaf(pRtree, &cell, pNode->iNode, &pInsert);
+    rc = ChooseLeaf(pRtree, &cell, (int)pNode->iNode, &pInsert);
     if( rc==SQLITE_OK ){
       int rc2;
-      rc = rtreeInsertCell(pRtree, pInsert, &cell, pNode->iNode);
+      rc = rtreeInsertCell(pRtree, pInsert, &cell, (int)pNode->iNode);
       rc2 = nodeRelease(pRtree, pInsert);
       if( rc==SQLITE_OK ){
         rc = rc2;
@@ -101601,20 +134864,124 @@ static int newRowid(Rtree *pRtree, i64 *piRowid){
   return rc;
 }
 
-#ifndef NDEBUG
-static int hashIsEmpty(Rtree *pRtree){
-  int ii;
-  for(ii=0; ii<HASHSIZE; ii++){
-    assert( !pRtree->aHash[ii] );
+/*
+** Remove the entry with rowid=iDelete from the r-tree structure.
+*/
+static int rtreeDeleteRowid(Rtree *pRtree, sqlite3_int64 iDelete){
+  int rc;                         /* Return code */
+  RtreeNode *pLeaf;               /* Leaf node containing record iDelete */
+  int iCell;                      /* Index of iDelete cell in pLeaf */
+  RtreeNode *pRoot;               /* Root node of rtree structure */
+
+
+  /* Obtain a reference to the root node to initialise Rtree.iDepth */
+  rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+
+  /* Obtain a reference to the leaf node that contains the entry 
+  ** about to be deleted. 
+  */
+  if( rc==SQLITE_OK ){
+    rc = findLeafNode(pRtree, iDelete, &pLeaf);
   }
-  return 1;
+
+  /* Delete the cell in question from the leaf node. */
+  if( rc==SQLITE_OK ){
+    int rc2;
+    rc = nodeRowidIndex(pRtree, pLeaf, iDelete, &iCell);
+    if( rc==SQLITE_OK ){
+      rc = deleteCell(pRtree, pLeaf, iCell, 0);
+    }
+    rc2 = nodeRelease(pRtree, pLeaf);
+    if( rc==SQLITE_OK ){
+      rc = rc2;
+    }
+  }
+
+  /* Delete the corresponding entry in the <rtree>_rowid table. */
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pRtree->pDeleteRowid, 1, iDelete);
+    sqlite3_step(pRtree->pDeleteRowid);
+    rc = sqlite3_reset(pRtree->pDeleteRowid);
+  }
+
+  /* Check if the root node now has exactly one child. If so, remove
+  ** it, schedule the contents of the child for reinsertion and 
+  ** reduce the tree height by one.
+  **
+  ** This is equivalent to copying the contents of the child into
+  ** the root node (the operation that Gutman's paper says to perform 
+  ** in this scenario).
+  */
+  if( rc==SQLITE_OK && pRtree->iDepth>0 && NCELL(pRoot)==1 ){
+    int rc2;
+    RtreeNode *pChild;
+    i64 iChild = nodeGetRowid(pRtree, pRoot, 0);
+    rc = nodeAcquire(pRtree, iChild, pRoot, &pChild);
+    if( rc==SQLITE_OK ){
+      rc = removeNode(pRtree, pChild, pRtree->iDepth-1);
+    }
+    rc2 = nodeRelease(pRtree, pChild);
+    if( rc==SQLITE_OK ) rc = rc2;
+    if( rc==SQLITE_OK ){
+      pRtree->iDepth--;
+      writeInt16(pRoot->zData, pRtree->iDepth);
+      pRoot->isDirty = 1;
+    }
+  }
+
+  /* Re-insert the contents of any underfull nodes removed from the tree. */
+  for(pLeaf=pRtree->pDeleted; pLeaf; pLeaf=pRtree->pDeleted){
+    if( rc==SQLITE_OK ){
+      rc = reinsertNodeContent(pRtree, pLeaf);
+    }
+    pRtree->pDeleted = pLeaf->pNext;
+    sqlite3_free(pLeaf);
+  }
+
+  /* Release the reference to the root node. */
+  if( rc==SQLITE_OK ){
+    rc = nodeRelease(pRtree, pRoot);
+  }else{
+    nodeRelease(pRtree, pRoot);
+  }
+
+  return rc;
 }
-#endif
+
+/*
+** Rounding constants for float->double conversion.
+*/
+#define RNDTOWARDS  (1.0 - 1.0/8388608.0)  /* Round towards zero */
+#define RNDAWAY     (1.0 + 1.0/8388608.0)  /* Round away from zero */
+
+#if !defined(SQLITE_RTREE_INT_ONLY)
+/*
+** Convert an sqlite3_value into an RtreeValue (presumably a float)
+** while taking care to round toward negative or positive, respectively.
+*/
+static RtreeValue rtreeValueDown(sqlite3_value *v){
+  double d = sqlite3_value_double(v);
+  float f = (float)d;
+  if( f>d ){
+    f = (float)(d*(d<0 ? RNDAWAY : RNDTOWARDS));
+  }
+  return f;
+}
+static RtreeValue rtreeValueUp(sqlite3_value *v){
+  double d = sqlite3_value_double(v);
+  float f = (float)d;
+  if( f<d ){
+    f = (float)(d*(d<0 ? RNDTOWARDS : RNDAWAY));
+  }
+  return f;
+}
+#endif /* !defined(SQLITE_RTREE_INT_ONLY) */
+
 
 /*
 ** The xUpdate method for rtree module virtual tables.
 */
-int rtreeUpdate(
+static int rtreeUpdate(
   sqlite3_vtab *pVtab, 
   int nData, 
   sqlite3_value **azData, 
@@ -101622,114 +134989,41 @@ int rtreeUpdate(
 ){
   Rtree *pRtree = (Rtree *)pVtab;
   int rc = SQLITE_OK;
+  RtreeCell cell;                 /* New cell to insert if nData>1 */
+  int bHaveRowid = 0;             /* Set to 1 after new rowid is determined */
 
   rtreeReference(pRtree);
-
   assert(nData>=1);
-  assert(hashIsEmpty(pRtree));
 
-  /* If azData[0] is not an SQL NULL value, it is the rowid of a
-  ** record to delete from the r-tree table. The following block does
-  ** just that.
+  /* Constraint handling. A write operation on an r-tree table may return
+  ** SQLITE_CONSTRAINT for two reasons:
+  **
+  **   1. A duplicate rowid value, or
+  **   2. The supplied data violates the "x2>=x1" constraint.
+  **
+  ** In the first case, if the conflict-handling mode is REPLACE, then
+  ** the conflicting row can be removed before proceeding. In the second
+  ** case, SQLITE_CONSTRAINT must be returned regardless of the
+  ** conflict-handling mode specified by the user.
   */
-  if( sqlite3_value_type(azData[0])!=SQLITE_NULL ){
-    i64 iDelete;                /* The rowid to delete */
-    RtreeNode *pLeaf;           /* Leaf node containing record iDelete */
-    int iCell;                  /* Index of iDelete cell in pLeaf */
-    RtreeNode *pRoot;
-
-    /* Obtain a reference to the root node to initialise Rtree.iDepth */
-    rc = nodeAcquire(pRtree, 1, 0, &pRoot);
-
-    /* Obtain a reference to the leaf node that contains the entry 
-    ** about to be deleted. 
-    */
-    if( rc==SQLITE_OK ){
-      iDelete = sqlite3_value_int64(azData[0]);
-      rc = findLeafNode(pRtree, iDelete, &pLeaf);
-    }
-
-    /* Delete the cell in question from the leaf node. */
-    if( rc==SQLITE_OK ){
-      int rc2;
-      iCell = nodeRowidIndex(pRtree, pLeaf, iDelete);
-      rc = deleteCell(pRtree, pLeaf, iCell, 0);
-      rc2 = nodeRelease(pRtree, pLeaf);
-      if( rc==SQLITE_OK ){
-        rc = rc2;
-      }
-    }
-
-    /* Delete the corresponding entry in the <rtree>_rowid table. */
-    if( rc==SQLITE_OK ){
-      sqlite3_bind_int64(pRtree->pDeleteRowid, 1, iDelete);
-      sqlite3_step(pRtree->pDeleteRowid);
-      rc = sqlite3_reset(pRtree->pDeleteRowid);
-    }
-
-    /* Check if the root node now has exactly one child. If so, remove
-    ** it, schedule the contents of the child for reinsertion and 
-    ** reduce the tree height by one.
-    **
-    ** This is equivalent to copying the contents of the child into
-    ** the root node (the operation that Gutman's paper says to perform 
-    ** in this scenario).
-    */
-    if( rc==SQLITE_OK && pRtree->iDepth>0 ){
-      if( rc==SQLITE_OK && NCELL(pRoot)==1 ){
-        RtreeNode *pChild;
-        i64 iChild = nodeGetRowid(pRtree, pRoot, 0);
-        rc = nodeAcquire(pRtree, iChild, pRoot, &pChild);
-        if( rc==SQLITE_OK ){
-          rc = removeNode(pRtree, pChild, pRtree->iDepth-1);
-        }
-        if( rc==SQLITE_OK ){
-          pRtree->iDepth--;
-          writeInt16(pRoot->zData, pRtree->iDepth);
-          pRoot->isDirty = 1;
-        }
-      }
-    }
-
-    /* Re-insert the contents of any underfull nodes removed from the tree. */
-    for(pLeaf=pRtree->pDeleted; pLeaf; pLeaf=pRtree->pDeleted){
-      if( rc==SQLITE_OK ){
-        rc = reinsertNodeContent(pRtree, pLeaf);
-      }
-      pRtree->pDeleted = pLeaf->pNext;
-      sqlite3_free(pLeaf);
-    }
-
-    /* Release the reference to the root node. */
-    if( rc==SQLITE_OK ){
-      rc = nodeRelease(pRtree, pRoot);
-    }else{
-      nodeRelease(pRtree, pRoot);
-    }
-  }
-
-  /* If the azData[] array contains more than one element, elements
-  ** (azData[2]..azData[argc-1]) contain a new record to insert into
-  ** the r-tree structure.
-  */
-  if( rc==SQLITE_OK && nData>1 ){
-    /* Insert a new record into the r-tree */
-    RtreeCell cell;
+  if( nData>1 ){
     int ii;
-    RtreeNode *pLeaf;
 
     /* Populate the cell.aCoord[] array. The first coordinate is azData[3]. */
     assert( nData==(pRtree->nDim*2 + 3) );
+#ifndef SQLITE_RTREE_INT_ONLY
     if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
       for(ii=0; ii<(pRtree->nDim*2); ii+=2){
-        cell.aCoord[ii].f = (float)sqlite3_value_double(azData[ii+3]);
-        cell.aCoord[ii+1].f = (float)sqlite3_value_double(azData[ii+4]);
+        cell.aCoord[ii].f = rtreeValueDown(azData[ii+3]);
+        cell.aCoord[ii+1].f = rtreeValueUp(azData[ii+4]);
         if( cell.aCoord[ii].f>cell.aCoord[ii+1].f ){
           rc = SQLITE_CONSTRAINT;
           goto constraint;
         }
       }
-    }else{
+    }else
+#endif
+    {
       for(ii=0; ii<(pRtree->nDim*2); ii+=2){
         cell.aCoord[ii].i = sqlite3_value_int(azData[ii+3]);
         cell.aCoord[ii+1].i = sqlite3_value_int(azData[ii+4]);
@@ -101740,19 +135034,51 @@ int rtreeUpdate(
       }
     }
 
-    /* Figure out the rowid of the new row. */
-    if( sqlite3_value_type(azData[2])==SQLITE_NULL ){
-      rc = newRowid(pRtree, &cell.iRowid);
-    }else{
+    /* If a rowid value was supplied, check if it is already present in 
+    ** the table. If so, the constraint has failed. */
+    if( sqlite3_value_type(azData[2])!=SQLITE_NULL ){
       cell.iRowid = sqlite3_value_int64(azData[2]);
-      sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
-      if( SQLITE_ROW==sqlite3_step(pRtree->pReadRowid) ){
-        sqlite3_reset(pRtree->pReadRowid);
-        rc = SQLITE_CONSTRAINT;
-        goto constraint;
+      if( sqlite3_value_type(azData[0])==SQLITE_NULL
+       || sqlite3_value_int64(azData[0])!=cell.iRowid
+      ){
+        int steprc;
+        sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
+        steprc = sqlite3_step(pRtree->pReadRowid);
+        rc = sqlite3_reset(pRtree->pReadRowid);
+        if( SQLITE_ROW==steprc ){
+          if( sqlite3_vtab_on_conflict(pRtree->db)==SQLITE_REPLACE ){
+            rc = rtreeDeleteRowid(pRtree, cell.iRowid);
+          }else{
+            rc = SQLITE_CONSTRAINT;
+            goto constraint;
+          }
+        }
       }
-      rc = sqlite3_reset(pRtree->pReadRowid);
+      bHaveRowid = 1;
     }
+  }
+
+  /* If azData[0] is not an SQL NULL value, it is the rowid of a
+  ** record to delete from the r-tree table. The following block does
+  ** just that.
+  */
+  if( sqlite3_value_type(azData[0])!=SQLITE_NULL ){
+    rc = rtreeDeleteRowid(pRtree, sqlite3_value_int64(azData[0]));
+  }
+
+  /* If the azData[] array contains more than one element, elements
+  ** (azData[2]..azData[argc-1]) contain a new record to insert into
+  ** the r-tree structure.
+  */
+  if( rc==SQLITE_OK && nData>1 ){
+    /* Insert the new record into the r-tree */
+    RtreeNode *pLeaf;
+
+    /* Figure out the rowid of the new row. */
+    if( bHaveRowid==0 ){
+      rc = newRowid(pRtree, &cell.iRowid);
+    }
+    *pRowid = cell.iRowid;
 
     if( rc==SQLITE_OK ){
       rc = ChooseLeaf(pRtree, &cell, 0, &pLeaf);
@@ -101795,7 +135121,7 @@ static int rtreeRename(sqlite3_vtab *pVtab, const char *zNewName){
 }
 
 static sqlite3_module rtreeModule = {
-  0,                         /* iVersion */
+  0,                          /* iVersion */
   rtreeCreate,                /* xCreate - create a table */
   rtreeConnect,               /* xConnect - connect to an existing table */
   rtreeBestIndex,             /* xBestIndex - Determine search strategy */
@@ -101814,7 +135140,10 @@ static sqlite3_module rtreeModule = {
   0,                          /* xCommit - commit transaction */
   0,                          /* xRollback - rollback transaction */
   0,                          /* xFindFunction - function overloading */
-  rtreeRename                 /* xRename - rename the table */
+  rtreeRename,                /* xRename - rename the table */
+  0,                          /* xSavepoint */
+  0,                          /* xRelease */
+  0                           /* xRollbackTo */
 };
 
 static int rtreeSqlInit(
@@ -101890,31 +135219,69 @@ static int rtreeSqlInit(
 }
 
 /*
-** This routine queries database handle db for the page-size used by
-** database zDb. If successful, the page-size in bytes is written to
-** *piPageSize and SQLITE_OK returned. Otherwise, and an SQLite error 
-** code is returned.
+** The second argument to this function contains the text of an SQL statement
+** that returns a single integer value. The statement is compiled and executed
+** using database connection db. If successful, the integer value returned
+** is written to *piVal and SQLITE_OK returned. Otherwise, an SQLite error
+** code is returned and the value of *piVal after returning is not defined.
 */
-static int getPageSize(sqlite3 *db, const char *zDb, int *piPageSize){
+static int getIntFromStmt(sqlite3 *db, const char *zSql, int *piVal){
   int rc = SQLITE_NOMEM;
+  if( zSql ){
+    sqlite3_stmt *pStmt = 0;
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        *piVal = sqlite3_column_int(pStmt, 0);
+      }
+      rc = sqlite3_finalize(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is called from within the xConnect() or xCreate() method to
+** determine the node-size used by the rtree table being created or connected
+** to. If successful, pRtree->iNodeSize is populated and SQLITE_OK returned.
+** Otherwise, an SQLite error code is returned.
+**
+** If this function is being called as part of an xConnect(), then the rtree
+** table already exists. In this case the node-size is determined by inspecting
+** the root node of the tree.
+**
+** Otherwise, for an xCreate(), use 64 bytes less than the database page-size. 
+** This ensures that each node is stored on a single database page. If the 
+** database page-size is so large that more than RTREE_MAXCELLS entries 
+** would fit in a single node, use a smaller node-size.
+*/
+static int getNodeSize(
+  sqlite3 *db,                    /* Database handle */
+  Rtree *pRtree,                  /* Rtree handle */
+  int isCreate                    /* True for xCreate, false for xConnect */
+){
+  int rc;
   char *zSql;
-  sqlite3_stmt *pStmt = 0;
-
-  zSql = sqlite3_mprintf("PRAGMA %Q.page_size", zDb);
-  if( !zSql ){
-    return SQLITE_NOMEM;
+  if( isCreate ){
+    int iPageSize = 0;
+    zSql = sqlite3_mprintf("PRAGMA %Q.page_size", pRtree->zDb);
+    rc = getIntFromStmt(db, zSql, &iPageSize);
+    if( rc==SQLITE_OK ){
+      pRtree->iNodeSize = iPageSize-64;
+      if( (4+pRtree->nBytesPerCell*RTREE_MAXCELLS)<pRtree->iNodeSize ){
+        pRtree->iNodeSize = 4+pRtree->nBytesPerCell*RTREE_MAXCELLS;
+      }
+    }
+  }else{
+    zSql = sqlite3_mprintf(
+        "SELECT length(data) FROM '%q'.'%q_node' WHERE nodeno = 1",
+        pRtree->zDb, pRtree->zName
+    );
+    rc = getIntFromStmt(db, zSql, &pRtree->iNodeSize);
   }
 
-  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
   sqlite3_free(zSql);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
-
-  if( SQLITE_ROW==sqlite3_step(pStmt) ){
-    *piPageSize = sqlite3_column_int(pStmt, 0);
-  }
-  return sqlite3_finalize(pStmt);
+  return rc;
 }
 
 /* 
@@ -101935,11 +135302,10 @@ static int rtreeInit(
   int isCreate                        /* True for xCreate, false for xConnect */
 ){
   int rc = SQLITE_OK;
-  int iPageSize = 0;
   Rtree *pRtree;
   int nDb;              /* Length of string argv[1] */
   int nName;            /* Length of string argv[2] */
-  int eCoordType = (int)pAux;
+  int eCoordType = (pAux ? RTREE_COORD_INT32 : RTREE_COORD_REAL32);
 
   const char *aErrMsg[] = {
     0,                                                    /* 0 */
@@ -101954,14 +135320,11 @@ static int rtreeInit(
     return SQLITE_ERROR;
   }
 
-  rc = getPageSize(db, argv[1], &iPageSize);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
+  sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
 
   /* Allocate the sqlite3_vtab structure */
-  nDb = strlen(argv[1]);
-  nName = strlen(argv[2]);
+  nDb = (int)strlen(argv[1]);
+  nName = (int)strlen(argv[2]);
   pRtree = (Rtree *)sqlite3_malloc(sizeof(Rtree)+nDb+nName+2);
   if( !pRtree ){
     return SQLITE_NOMEM;
@@ -101977,42 +135340,37 @@ static int rtreeInit(
   memcpy(pRtree->zDb, argv[1], nDb);
   memcpy(pRtree->zName, argv[2], nName);
 
-  /* Figure out the node size to use. By default, use 64 bytes less than
-  ** the database page-size. This ensures that each node is stored on
-  ** a single database page.
-  **
-  ** If the databasd page-size is so large that more than RTREE_MAXCELLS
-  ** entries would fit in a single node, use a smaller node-size.
-  */
-  pRtree->iNodeSize = iPageSize-64;
-  if( (4+pRtree->nBytesPerCell*RTREE_MAXCELLS)<pRtree->iNodeSize ){
-    pRtree->iNodeSize = 4+pRtree->nBytesPerCell*RTREE_MAXCELLS;
-  }
+  /* Figure out the node size to use. */
+  rc = getNodeSize(db, pRtree, isCreate);
 
   /* Create/Connect to the underlying relational database schema. If
   ** that is successful, call sqlite3_declare_vtab() to configure
   ** the r-tree table schema.
   */
-  if( (rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate)) ){
-    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
-  }else{
-    char *zSql = sqlite3_mprintf("CREATE TABLE x(%s", argv[3]);
-    char *zTmp;
-    int ii;
-    for(ii=4; zSql && ii<argc; ii++){
-      zTmp = zSql;
-      zSql = sqlite3_mprintf("%s, %s", zTmp, argv[ii]);
-      sqlite3_free(zTmp);
+  if( rc==SQLITE_OK ){
+    if( (rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate)) ){
+      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    }else{
+      char *zSql = sqlite3_mprintf("CREATE TABLE x(%s", argv[3]);
+      char *zTmp;
+      int ii;
+      for(ii=4; zSql && ii<argc; ii++){
+        zTmp = zSql;
+        zSql = sqlite3_mprintf("%s, %s", zTmp, argv[ii]);
+        sqlite3_free(zTmp);
+      }
+      if( zSql ){
+        zTmp = zSql;
+        zSql = sqlite3_mprintf("%s);", zTmp);
+        sqlite3_free(zTmp);
+      }
+      if( !zSql ){
+        rc = SQLITE_NOMEM;
+      }else if( SQLITE_OK!=(rc = sqlite3_declare_vtab(db, zSql)) ){
+        *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+      }
+      sqlite3_free(zSql);
     }
-    if( zSql ){
-      zTmp = zSql;
-      zSql = sqlite3_mprintf("%s);", zTmp);
-      sqlite3_free(zTmp);
-    }
-    if( !zSql || sqlite3_declare_vtab(db, zSql) ){
-      rc = SQLITE_NOMEM;
-    }
-    sqlite3_free(zSql);
   }
 
   if( rc==SQLITE_OK ){
@@ -102046,6 +135404,7 @@ static void rtreenode(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
   Rtree tree;
   int ii;
 
+  UNUSED_PARAMETER(nArg);
   memset(&node, 0, sizeof(RtreeNode));
   memset(&tree, 0, sizeof(Rtree));
   tree.nDim = sqlite3_value_int(apArg[0]);
@@ -102059,11 +135418,17 @@ static void rtreenode(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
     int jj;
 
     nodeGetCell(&tree, &node, ii, &cell);
-    sqlite3_snprintf(512-nCell,&zCell[nCell],"%d", cell.iRowid);
-    nCell = strlen(zCell);
+    sqlite3_snprintf(512-nCell,&zCell[nCell],"%lld", cell.iRowid);
+    nCell = (int)strlen(zCell);
     for(jj=0; jj<tree.nDim*2; jj++){
-      sqlite3_snprintf(512-nCell,&zCell[nCell]," %f",(double)cell.aCoord[jj].f);
-      nCell = strlen(zCell);
+#ifndef SQLITE_RTREE_INT_ONLY
+      sqlite3_snprintf(512-nCell,&zCell[nCell], " %f",
+                       (double)cell.aCoord[jj].f);
+#else
+      sqlite3_snprintf(512-nCell,&zCell[nCell], " %d",
+                       cell.aCoord[jj].i);
+#endif
+      nCell = (int)strlen(zCell);
     }
 
     if( zText ){
@@ -102079,6 +135444,7 @@ static void rtreenode(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
 }
 
 static void rtreedepth(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
+  UNUSED_PARAMETER(nArg);
   if( sqlite3_value_type(apArg[0])!=SQLITE_BLOB 
    || sqlite3_value_bytes(apArg[0])<2
   ){
@@ -102095,18 +135461,19 @@ static void rtreedepth(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
 ** function "rtreenode".
 */
 SQLITE_PRIVATE int sqlite3RtreeInit(sqlite3 *db){
-  int rc = SQLITE_OK;
+  const int utf8 = SQLITE_UTF8;
+  int rc;
 
+  rc = sqlite3_create_function(db, "rtreenode", 2, utf8, 0, rtreenode, 0, 0);
   if( rc==SQLITE_OK ){
-    int utf8 = SQLITE_UTF8;
-    rc = sqlite3_create_function(db, "rtreenode", 2, utf8, 0, rtreenode, 0, 0);
-  }
-  if( rc==SQLITE_OK ){
-    int utf8 = SQLITE_UTF8;
     rc = sqlite3_create_function(db, "rtreedepth", 1, utf8, 0,rtreedepth, 0, 0);
   }
   if( rc==SQLITE_OK ){
+#ifdef SQLITE_RTREE_INT_ONLY
+    void *c = (void *)RTREE_COORD_INT32;
+#else
     void *c = (void *)RTREE_COORD_REAL32;
+#endif
     rc = sqlite3_create_module_v2(db, "rtree", &rtreeModule, c, 0);
   }
   if( rc==SQLITE_OK ){
@@ -102117,6 +135484,74 @@ SQLITE_PRIVATE int sqlite3RtreeInit(sqlite3 *db){
   return rc;
 }
 
+/*
+** A version of sqlite3_free() that can be used as a callback. This is used
+** in two places - as the destructor for the blob value returned by the
+** invocation of a geometry function, and as the destructor for the geometry
+** functions themselves.
+*/
+static void doSqlite3Free(void *p){
+  sqlite3_free(p);
+}
+
+/*
+** Each call to sqlite3_rtree_geometry_callback() creates an ordinary SQLite
+** scalar user function. This C function is the callback used for all such
+** registered SQL functions.
+**
+** The scalar user functions return a blob that is interpreted by r-tree
+** table MATCH operators.
+*/
+static void geomCallback(sqlite3_context *ctx, int nArg, sqlite3_value **aArg){
+  RtreeGeomCallback *pGeomCtx = (RtreeGeomCallback *)sqlite3_user_data(ctx);
+  RtreeMatchArg *pBlob;
+  int nBlob;
+
+  nBlob = sizeof(RtreeMatchArg) + (nArg-1)*sizeof(RtreeDValue);
+  pBlob = (RtreeMatchArg *)sqlite3_malloc(nBlob);
+  if( !pBlob ){
+    sqlite3_result_error_nomem(ctx);
+  }else{
+    int i;
+    pBlob->magic = RTREE_GEOMETRY_MAGIC;
+    pBlob->xGeom = pGeomCtx->xGeom;
+    pBlob->pContext = pGeomCtx->pContext;
+    pBlob->nParam = nArg;
+    for(i=0; i<nArg; i++){
+#ifdef SQLITE_RTREE_INT_ONLY
+      pBlob->aParam[i] = sqlite3_value_int64(aArg[i]);
+#else
+      pBlob->aParam[i] = sqlite3_value_double(aArg[i]);
+#endif
+    }
+    sqlite3_result_blob(ctx, pBlob, nBlob, doSqlite3Free);
+  }
+}
+
+/*
+** Register a new geometry function for use with the r-tree MATCH operator.
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,
+  const char *zGeom,
+  int (*xGeom)(sqlite3_rtree_geometry *, int, RtreeDValue *, int *),
+  void *pContext
+){
+  RtreeGeomCallback *pGeomCtx;      /* Context object for new user-function */
+
+  /* Allocate and populate the context object. */
+  pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback));
+  if( !pGeomCtx ) return SQLITE_NOMEM;
+  pGeomCtx->xGeom = xGeom;
+  pGeomCtx->pContext = pContext;
+
+  /* Create the new user-function. Register a destructor function to delete
+  ** the context object when it is no longer required.  */
+  return sqlite3_create_function_v2(db, zGeom, -1, SQLITE_ANY, 
+      (void *)pGeomCtx, geomCallback, 0, 0, doSqlite3Free
+  );
+}
+
 #if !SQLITE_CORE
 SQLITE_API int sqlite3_extension_init(
   sqlite3 *db,
@@ -102143,7 +135578,7 @@ SQLITE_API int sqlite3_extension_init(
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
+** $Id: icu.c,v 1.7 2007/12/13 21:54:11 drh Exp $
 **
 ** This file implements an integration between the ICU library 
 ** ("International Components for Unicode", an open-source library 
@@ -102170,6 +135605,7 @@ SQLITE_API int sqlite3_extension_init(
 #include <unicode/ustring.h>
 #include <unicode/ucol.h>
 
+/* #include <assert.h> */
 
 #ifndef SQLITE_CORE
   SQLITE_EXTENSION_INIT1
@@ -102378,6 +135814,8 @@ static void icuRegexpFunc(sqlite3_context *p, int nArg, sqlite3_value **apArg){
   UBool res;
   const UChar *zString = sqlite3_value_text16(apArg[1]);
 
+  (void)nArg;  /* Unused parameter */
+
   /* If the left hand side of the regexp operator is NULL, 
   ** then the result is also NULL. 
   */
@@ -102585,7 +136023,7 @@ SQLITE_PRIVATE int sqlite3IcuInit(sqlite3 *db){
     void *pContext;                           /* sqlite3_user_data() context */
     void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
   } scalars[] = {
-    {"regexp",-1, SQLITE_ANY,          0, icuRegexpFunc},
+    {"regexp", 2, SQLITE_ANY,          0, icuRegexpFunc},
 
     {"lower",  1, SQLITE_UTF16,        0, icuCaseFunc16},
     {"lower",  2, SQLITE_UTF16,        0, icuCaseFunc16},
@@ -102606,7 +136044,7 @@ SQLITE_PRIVATE int sqlite3IcuInit(sqlite3 *db){
   int rc = SQLITE_OK;
   int i;
 
-  for(i=0; rc==SQLITE_OK && i<(sizeof(scalars)/sizeof(struct IcuScalar)); i++){
+  for(i=0; rc==SQLITE_OK && i<(int)(sizeof(scalars)/sizeof(scalars[0])); i++){
     struct IcuScalar *p = &scalars[i];
     rc = sqlite3_create_function(
         db, p->zName, p->nArg, p->enc, p->pContext, p->xFunc, 0, 0
@@ -102643,15 +136081,16 @@ SQLITE_API int sqlite3_extension_init(
 **
 *************************************************************************
 ** This file implements a tokenizer for fts3 based on the ICU library.
-** 
-** $Id: sqlite3.c,v 1.5 2009-01-28 09:07:54 guy Exp $
 */
-
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 #ifdef SQLITE_ENABLE_ICU
 
+/* #include <assert.h> */
+/* #include <string.h> */
 
 #include <unicode/ubrk.h>
+/* #include <unicode/ucol.h> */
+/* #include <unicode/ustring.h> */
 #include <unicode/utf16.h>
 
 typedef struct IcuTokenizer IcuTokenizer;
@@ -102740,7 +136179,10 @@ static int icuOpen(
 
   *ppCursor = 0;
 
-  if( nInput<0 ){
+  if( zInput==0 ){
+    nInput = 0;
+    zInput = "";
+  }else if( nInput<0 ){
     nInput = strlen(zInput);
   }
   nChar = nInput+1;
@@ -102826,7 +136268,7 @@ static int icuNext(
 
     while( iStart<iEnd ){
       int iWhite = iStart;
-      U8_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
+      U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
       if( u_isspace(c) ){
         iStart = iWhite;
       }else{
diff --git a/sqlite/sqlite3.h b/sqlite/sqlite3.h
index 964dd5f87..5a1f9d462 100755
--- a/sqlite/sqlite3.h
+++ b/sqlite/sqlite3.h
@@ -18,8 +18,8 @@
 ** Some of the definitions that are in this file are marked as
 ** "experimental".  Experimental interfaces are normally new
 ** features recently added to SQLite.  We do not anticipate changes
-** to experimental interfaces but reserve to make minor changes if
-** experience from use "in the wild" suggest such changes are prudent.
+** to experimental interfaces but reserve the right to make minor changes
+** if experience from use "in the wild" suggest such changes are prudent.
 **
 ** The official C-language API documentation for SQLite is derived
 ** from comments in this file.  This file is the authoritative source
@@ -29,8 +29,6 @@
 ** The makefile makes some minor changes to this file (such as inserting
 ** the version number) and changes its name to "sqlite3.h" as
 ** part of the build process.
-**
-** @(#) $Id: sqlite3.h,v 1.8 2009-01-28 09:09:17 guy Exp $
 */
 #ifndef _SQLITE3_H_
 #define _SQLITE3_H_
@@ -51,10 +49,15 @@ extern "C" {
 # define SQLITE_EXTERN extern
 #endif
 
+#ifndef SQLITE_API
+# define SQLITE_API
+#endif
+
+
 /*
 ** These no-op macros are used in front of interfaces to mark those
 ** interfaces as either deprecated or experimental.  New applications
-** should not use deprecated intrfaces - they are support for backwards
+** should not use deprecated interfaces - they are support for backwards
 ** compatibility only.  Application writers should be aware that
 ** experimental interfaces are subject to change in point releases.
 **
@@ -78,74 +81,107 @@ extern "C" {
 #endif
 
 /*
-** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100>
+** CAPI3REF: Compile-Time Library Version Numbers
 **
-** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in
-** the sqlite3.h file specify the version of SQLite with which
-** that header file is associated.
+** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
+** evaluates to a string literal that is the SQLite version in the
+** format "X.Y.Z" where X is the major version number (always 3 for
+** SQLite3) and Y is the minor version number and Z is the release number.)^
+** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
+** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
+** numbers used in [SQLITE_VERSION].)^
+** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
+** be larger than the release from which it is derived.  Either Y will
+** be held constant and Z will be incremented or else Y will be incremented
+** and Z will be reset to zero.
 **
-** The "version" of SQLite is a string of the form "X.Y.Z".
-** The phrase "alpha" or "beta" might be appended after the Z.
-** The X value is major version number always 3 in SQLite3.
-** The X value only changes when backwards compatibility is
-** broken and we intend to never break backwards compatibility.
-** The Y value is the minor version number and only changes when
-** there are major feature enhancements that are forwards compatible
-** but not backwards compatible.
-** The Z value is the release number and is incremented with
-** each release but resets back to 0 whenever Y is incremented.
+** Since version 3.6.18, SQLite source code has been stored in the
+** <a href="http://www.fossil-scm.org/">Fossil configuration management
+** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
+** a string which identifies a particular check-in of SQLite
+** within its configuration management system.  ^The SQLITE_SOURCE_ID
+** string contains the date and time of the check-in (UTC) and an SHA1
+** hash of the entire source tree.
 **
-** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()].
-**
-** INVARIANTS:
-**
-** {H10011} The SQLITE_VERSION #define in the sqlite3.h header file shall
-**          evaluate to a string literal that is the SQLite version
-**          with which the header file is associated.
-**
-** {H10014} The SQLITE_VERSION_NUMBER #define shall resolve to an integer
-**          with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z
-**          are the major version, minor version, and release number.
+** See also: [sqlite3_libversion()],
+** [sqlite3_libversion_number()], [sqlite3_sourceid()],
+** [sqlite_version()] and [sqlite_source_id()].
 */
-#define SQLITE_VERSION         "3.6.10"
-#define SQLITE_VERSION_NUMBER  3006010
+#define SQLITE_VERSION        "3.7.14.1"
+#define SQLITE_VERSION_NUMBER 3007014
+#define SQLITE_SOURCE_ID      "2012-10-04 19:37:12 091570e46d04e84b67228e0bdbcd6e1fb60c6bdb"
 
 /*
-** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
-** KEYWORDS: sqlite3_version
+** CAPI3REF: Run-Time Library Version Numbers
+** KEYWORDS: sqlite3_version, sqlite3_sourceid
 **
-** These features provide the same information as the [SQLITE_VERSION]
-** and [SQLITE_VERSION_NUMBER] #defines in the header, but are associated
-** with the library instead of the header file.  Cautious programmers might
-** include a check in their application to verify that
-** sqlite3_libversion_number() always returns the value
-** [SQLITE_VERSION_NUMBER].
+** These interfaces provide the same information as the [SQLITE_VERSION],
+** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
+** but are associated with the library instead of the header file.  ^(Cautious
+** programmers might include assert() statements in their application to
+** verify that values returned by these interfaces match the macros in
+** the header, and thus insure that the application is
+** compiled with matching library and header files.
 **
-** The sqlite3_libversion() function returns the same information as is
-** in the sqlite3_version[] string constant.  The function is provided
-** for use in DLLs since DLL users usually do not have direct access to string
-** constants within the DLL.
+** <blockquote><pre>
+** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
+** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
+** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
+** </pre></blockquote>)^
 **
-** INVARIANTS:
+** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
+** macro.  ^The sqlite3_libversion() function returns a pointer to the
+** to the sqlite3_version[] string constant.  The sqlite3_libversion()
+** function is provided for use in DLLs since DLL users usually do not have
+** direct access to string constants within the DLL.  ^The
+** sqlite3_libversion_number() function returns an integer equal to
+** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns 
+** a pointer to a string constant whose value is the same as the 
+** [SQLITE_SOURCE_ID] C preprocessor macro.
 **
-** {H10021} The [sqlite3_libversion_number()] interface shall return
-**          an integer equal to [SQLITE_VERSION_NUMBER].
-**
-** {H10022} The [sqlite3_version] string constant shall contain
-**          the text of the [SQLITE_VERSION] string.
-**
-** {H10023} The [sqlite3_libversion()] function shall return
-**          a pointer to the [sqlite3_version] string constant.
+** See also: [sqlite_version()] and [sqlite_source_id()].
 */
-SQLITE_EXTERN const char sqlite3_version[];
-const char *sqlite3_libversion(void);
-int sqlite3_libversion_number(void);
+SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
+SQLITE_API const char *sqlite3_libversion(void);
+SQLITE_API const char *sqlite3_sourceid(void);
+SQLITE_API int sqlite3_libversion_number(void);
 
 /*
-** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100>
+** CAPI3REF: Run-Time Library Compilation Options Diagnostics
+**
+** ^The sqlite3_compileoption_used() function returns 0 or 1 
+** indicating whether the specified option was defined at 
+** compile time.  ^The SQLITE_ prefix may be omitted from the 
+** option name passed to sqlite3_compileoption_used().  
+**
+** ^The sqlite3_compileoption_get() function allows iterating
+** over the list of options that were defined at compile time by
+** returning the N-th compile time option string.  ^If N is out of range,
+** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_ 
+** prefix is omitted from any strings returned by 
+** sqlite3_compileoption_get().
+**
+** ^Support for the diagnostic functions sqlite3_compileoption_used()
+** and sqlite3_compileoption_get() may be omitted by specifying the 
+** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
+**
+** See also: SQL functions [sqlite_compileoption_used()] and
+** [sqlite_compileoption_get()] and the [compile_options pragma].
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
+SQLITE_API const char *sqlite3_compileoption_get(int N);
+#endif
+
+/*
+** CAPI3REF: Test To See If The Library Is Threadsafe
+**
+** ^The sqlite3_threadsafe() function returns zero if and only if
+** SQLite was compiled with mutexing code omitted due to the
+** [SQLITE_THREADSAFE] compile-time option being set to 0.
 **
 ** SQLite can be compiled with or without mutexes.  When
-** the [SQLITE_THREADSAFE] C preprocessor macro 1 or 2, mutexes
+** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
 ** are enabled and SQLite is threadsafe.  When the
 ** [SQLITE_THREADSAFE] macro is 0, 
 ** the mutexes are omitted.  Without the mutexes, it is not safe
@@ -154,42 +190,37 @@ int sqlite3_libversion_number(void);
 ** Enabling mutexes incurs a measurable performance penalty.
 ** So if speed is of utmost importance, it makes sense to disable
 ** the mutexes.  But for maximum safety, mutexes should be enabled.
-** The default behavior is for mutexes to be enabled.
+** ^The default behavior is for mutexes to be enabled.
 **
-** This interface can be used by a program to make sure that the
+** This interface can be used by an application to make sure that the
 ** version of SQLite that it is linking against was compiled with
 ** the desired setting of the [SQLITE_THREADSAFE] macro.
 **
 ** This interface only reports on the compile-time mutex setting
 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
-** SQLITE_THREADSAFE=1 then mutexes are enabled by default but
+** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
 ** can be fully or partially disabled using a call to [sqlite3_config()]
 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
-** or [SQLITE_CONFIG_MUTEX].  The return value of this function shows
-** only the default compile-time setting, not any run-time changes
-** to that setting.
+** or [SQLITE_CONFIG_MUTEX].  ^(The return value of the
+** sqlite3_threadsafe() function shows only the compile-time setting of
+** thread safety, not any run-time changes to that setting made by
+** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
+** is unchanged by calls to sqlite3_config().)^
 **
 ** See the [threading mode] documentation for additional information.
-**
-** INVARIANTS:
-**
-** {H10101} The [sqlite3_threadsafe()] function shall return zero if
-**          and only if SQLite was compiled with mutexing code omitted.
-**
-** {H10102} The value returned by the [sqlite3_threadsafe()] function
-**          shall remain the same across calls to [sqlite3_config()].
 */
-int sqlite3_threadsafe(void);
+SQLITE_API int sqlite3_threadsafe(void);
 
 /*
-** CAPI3REF: Database Connection Handle {H12000} <S40200>
+** CAPI3REF: Database Connection Handle
 ** KEYWORDS: {database connection} {database connections}
 **
 ** Each open SQLite database is represented by a pointer to an instance of
 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
-** is its destructor.  There are many other interfaces (such as
+** and [sqlite3_close_v2()] are its destructors.  There are many other
+** interfaces (such as
 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
 ** sqlite3 object.
@@ -197,7 +228,7 @@ int sqlite3_threadsafe(void);
 typedef struct sqlite3 sqlite3;
 
 /*
-** CAPI3REF: 64-Bit Integer Types {H10200} <S10110>
+** CAPI3REF: 64-Bit Integer Types
 ** KEYWORDS: sqlite_int64 sqlite_uint64
 **
 ** Because there is no cross-platform way to specify 64-bit integer types
@@ -207,13 +238,10 @@ typedef struct sqlite3 sqlite3;
 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
 ** compatibility only.
 **
-** INVARIANTS:
-**
-** {H10201} The [sqlite_int64] and [sqlite3_int64] type shall specify
-**          a 64-bit signed integer.
-**
-** {H10202} The [sqlite_uint64] and [sqlite3_uint64] type shall specify
-**          a 64-bit unsigned integer.
+** ^The sqlite3_int64 and sqlite_int64 types can store integer values
+** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
+** sqlite3_uint64 and sqlite_uint64 types can store integer values 
+** between 0 and +18446744073709551615 inclusive.
 */
 #ifdef SQLITE_INT64_TYPE
   typedef SQLITE_INT64_TYPE sqlite_int64;
@@ -237,57 +265,48 @@ typedef sqlite_uint64 sqlite3_uint64;
 #endif
 
 /*
-** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200>
+** CAPI3REF: Closing A Database Connection
 **
-** This routine is the destructor for the [sqlite3] object.
+** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
+** for the [sqlite3] object.
+** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if
+** the [sqlite3] object is successfully destroyed and all associated
+** resources are deallocated.
 **
-** Applications should [sqlite3_finalize | finalize] all [prepared statements]
-** and [sqlite3_blob_close | close] all [BLOB handles] associated with
-** the [sqlite3] object prior to attempting to close the object.
-** The [sqlite3_next_stmt()] interface can be used to locate all
-** [prepared statements] associated with a [database connection] if desired.
-** Typical code might look like this:
+** ^If the database connection is associated with unfinalized prepared
+** statements or unfinished sqlite3_backup objects then sqlite3_close()
+** will leave the database connection open and return [SQLITE_BUSY].
+** ^If sqlite3_close_v2() is called with unfinalized prepared statements
+** and unfinished sqlite3_backups, then the database connection becomes
+** an unusable "zombie" which will automatically be deallocated when the
+** last prepared statement is finalized or the last sqlite3_backup is
+** finished.  The sqlite3_close_v2() interface is intended for use with
+** host languages that are garbage collected, and where the order in which
+** destructors are called is arbitrary.
 **
-** <blockquote><pre>
-** sqlite3_stmt *pStmt;
-** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){
-** &nbsp;   sqlite3_finalize(pStmt);
-** }
-** </pre></blockquote>
+** Applications should [sqlite3_finalize | finalize] all [prepared statements],
+** [sqlite3_blob_close | close] all [BLOB handles], and 
+** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
+** with the [sqlite3] object prior to attempting to close the object.  ^If
+** sqlite3_close() is called on a [database connection] that still has
+** outstanding [prepared statements], [BLOB handles], and/or
+** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation
+** of resources is deferred until all [prepared statements], [BLOB handles],
+** and [sqlite3_backup] objects are also destroyed.
 **
-** If [sqlite3_close()] is invoked while a transaction is open,
+** ^If an [sqlite3] object is destroyed while a transaction is open,
 ** the transaction is automatically rolled back.
 **
-** INVARIANTS:
-**
-** {H12011} A successful call to [sqlite3_close(C)] shall destroy the
-**          [database connection] object C.
-**
-** {H12012} A successful call to [sqlite3_close(C)] shall return SQLITE_OK.
-**
-** {H12013} A successful call to [sqlite3_close(C)] shall release all
-**          memory and system resources associated with [database connection]
-**          C.
-**
-** {H12014} A call to [sqlite3_close(C)] on a [database connection] C that
-**          has one or more open [prepared statements] shall fail with
-**          an [SQLITE_BUSY] error code.
-**
-** {H12015} A call to [sqlite3_close(C)] where C is a NULL pointer shall
-**          be a harmless no-op returning SQLITE_OK.
-**
-** {H12019} When [sqlite3_close(C)] is invoked on a [database connection] C
-**          that has a pending transaction, the transaction shall be
-**          rolled back.
-**
-** ASSUMPTIONS:
-**
-** {A12016} The C parameter to [sqlite3_close(C)] must be either a NULL
-**          pointer or an [sqlite3] object pointer obtained
-**          from [sqlite3_open()], [sqlite3_open16()], or
-**          [sqlite3_open_v2()], and not previously closed.
+** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
+** must be either a NULL
+** pointer or an [sqlite3] object pointer obtained
+** from [sqlite3_open()], [sqlite3_open16()], or
+** [sqlite3_open_v2()], and not previously closed.
+** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
+** argument is a harmless no-op.
 */
-int sqlite3_close(sqlite3 *);
+SQLITE_API int sqlite3_close(sqlite3*);
+SQLITE_API int sqlite3_close_v2(sqlite3*);
 
 /*
 ** The type for a callback function.
@@ -297,114 +316,67 @@ int sqlite3_close(sqlite3 *);
 typedef int (*sqlite3_callback)(void*,int,char**, char**);
 
 /*
-** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000>
+** CAPI3REF: One-Step Query Execution Interface
 **
-** The sqlite3_exec() interface is a convenient way of running one or more
-** SQL statements without having to write a lot of C code.  The UTF-8 encoded
-** SQL statements are passed in as the second parameter to sqlite3_exec().
-** The statements are evaluated one by one until either an error or
-** an interrupt is encountered, or until they are all done.  The 3rd parameter
-** is an optional callback that is invoked once for each row of any query
-** results produced by the SQL statements.  The 5th parameter tells where
-** to write any error messages.
+** The sqlite3_exec() interface is a convenience wrapper around
+** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
+** that allows an application to run multiple statements of SQL
+** without having to use a lot of C code. 
 **
-** The error message passed back through the 5th parameter is held
-** in memory obtained from [sqlite3_malloc()].  To avoid a memory leak,
-** the calling application should call [sqlite3_free()] on any error
-** message returned through the 5th parameter when it has finished using
-** the error message.
+** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
+** semicolon-separate SQL statements passed into its 2nd argument,
+** in the context of the [database connection] passed in as its 1st
+** argument.  ^If the callback function of the 3rd argument to
+** sqlite3_exec() is not NULL, then it is invoked for each result row
+** coming out of the evaluated SQL statements.  ^The 4th argument to
+** sqlite3_exec() is relayed through to the 1st argument of each
+** callback invocation.  ^If the callback pointer to sqlite3_exec()
+** is NULL, then no callback is ever invoked and result rows are
+** ignored.
 **
-** If the SQL statement in the 2nd parameter is NULL or an empty string
-** or a string containing only whitespace and comments, then no SQL
-** statements are evaluated and the database is not changed.
+** ^If an error occurs while evaluating the SQL statements passed into
+** sqlite3_exec(), then execution of the current statement stops and
+** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
+** is not NULL then any error message is written into memory obtained
+** from [sqlite3_malloc()] and passed back through the 5th parameter.
+** To avoid memory leaks, the application should invoke [sqlite3_free()]
+** on error message strings returned through the 5th parameter of
+** of sqlite3_exec() after the error message string is no longer needed.
+** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
+** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
+** NULL before returning.
 **
-** The sqlite3_exec() interface is implemented in terms of
-** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
-** The sqlite3_exec() routine does nothing to the database that cannot be done
-** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
+** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
+** routine returns SQLITE_ABORT without invoking the callback again and
+** without running any subsequent SQL statements.
 **
-** INVARIANTS:
+** ^The 2nd argument to the sqlite3_exec() callback function is the
+** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
+** callback is an array of pointers to strings obtained as if from
+** [sqlite3_column_text()], one for each column.  ^If an element of a
+** result row is NULL then the corresponding string pointer for the
+** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
+** sqlite3_exec() callback is an array of pointers to strings where each
+** entry represents the name of corresponding result column as obtained
+** from [sqlite3_column_name()].
 **
-** {H12101} A successful invocation of [sqlite3_exec(D,S,C,A,E)]
-**          shall sequentially evaluate all of the UTF-8 encoded,
-**          semicolon-separated SQL statements in the zero-terminated
-**          string S within the context of the [database connection] D.
+** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
+** to an empty string, or a pointer that contains only whitespace and/or 
+** SQL comments, then no SQL statements are evaluated and the database
+** is not changed.
 **
-** {H12102} If the S parameter to [sqlite3_exec(D,S,C,A,E)] is NULL then
-**          the actions of the interface shall be the same as if the
-**          S parameter were an empty string.
+** Restrictions:
 **
-** {H12104} The return value of [sqlite3_exec()] shall be [SQLITE_OK] if all
-**          SQL statements run successfully and to completion.
-**
-** {H12105} The return value of [sqlite3_exec()] shall be an appropriate
-**          non-zero [error code] if any SQL statement fails.
-**
-** {H12107} If one or more of the SQL statements handed to [sqlite3_exec()]
-**          return results and the 3rd parameter is not NULL, then
-**          the callback function specified by the 3rd parameter shall be
-**          invoked once for each row of result.
-**
-** {H12110} If the callback returns a non-zero value then [sqlite3_exec()]
-**          shall abort the SQL statement it is currently evaluating,
-**          skip all subsequent SQL statements, and return [SQLITE_ABORT].
-**
-** {H12113} The [sqlite3_exec()] routine shall pass its 4th parameter through
-**          as the 1st parameter of the callback.
-**
-** {H12116} The [sqlite3_exec()] routine shall set the 2nd parameter of its
-**          callback to be the number of columns in the current row of
-**          result.
-**
-** {H12119} The [sqlite3_exec()] routine shall set the 3rd parameter of its
-**          callback to be an array of pointers to strings holding the
-**          values for each column in the current result set row as
-**          obtained from [sqlite3_column_text()].
-**
-** {H12122} The [sqlite3_exec()] routine shall set the 4th parameter of its
-**          callback to be an array of pointers to strings holding the
-**          names of result columns as obtained from [sqlite3_column_name()].
-**
-** {H12125} If the 3rd parameter to [sqlite3_exec()] is NULL then
-**          [sqlite3_exec()] shall silently discard query results.
-**
-** {H12131} If an error occurs while parsing or evaluating any of the SQL
-**          statements in the S parameter of [sqlite3_exec(D,S,C,A,E)] and if
-**          the E parameter is not NULL, then [sqlite3_exec()] shall store
-**          in *E an appropriate error message written into memory obtained
-**          from [sqlite3_malloc()].
-**
-** {H12134} The [sqlite3_exec(D,S,C,A,E)] routine shall set the value of
-**          *E to NULL if E is not NULL and there are no errors.
-**
-** {H12137} The [sqlite3_exec(D,S,C,A,E)] function shall set the [error code]
-**          and message accessible via [sqlite3_errcode()], 
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], and [sqlite3_errmsg16()].
-**
-** {H12138} If the S parameter to [sqlite3_exec(D,S,C,A,E)] is NULL or an
-**          empty string or contains nothing other than whitespace, comments,
-**          and/or semicolons, then results of [sqlite3_errcode()],
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], and [sqlite3_errmsg16()]
-**          shall reset to indicate no errors.
-**
-** ASSUMPTIONS:
-**
-** {A12141} The first parameter to [sqlite3_exec()] must be an valid and open
-**          [database connection].
-**
-** {A12142} The database connection must not be closed while
-**          [sqlite3_exec()] is running.
-**
-** {A12143} The calling function should use [sqlite3_free()] to free
-**          the memory that *errmsg is left pointing at once the error
-**          message is no longer needed.
-**
-** {A12145} The SQL statement text in the 2nd parameter to [sqlite3_exec()]
-**          must remain unchanged while [sqlite3_exec()] is running.
+** <ul>
+** <li> The application must insure that the 1st parameter to sqlite3_exec()
+**      is a valid and open [database connection].
+** <li> The application must not close [database connection] specified by
+**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not modify the SQL statement text passed into
+**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
+** </ul>
 */
-int sqlite3_exec(
+SQLITE_API int sqlite3_exec(
   sqlite3*,                                  /* An open database */
   const char *sql,                           /* SQL to be evaluated */
   int (*callback)(void*,int,char**,char**),  /* Callback function */
@@ -413,16 +385,17 @@ int sqlite3_exec(
 );
 
 /*
-** CAPI3REF: Result Codes {H10210} <S10700>
+** CAPI3REF: Result Codes
 ** KEYWORDS: SQLITE_OK {error code} {error codes}
 ** KEYWORDS: {result code} {result codes}
 **
 ** Many SQLite functions return an integer result code from the set shown
-** here in order to indicates success or failure.
+** here in order to indicate success or failure.
 **
 ** New error codes may be added in future versions of SQLite.
 **
-** See also: [SQLITE_IOERR_READ | extended result codes]
+** See also: [SQLITE_IOERR_READ | extended result codes],
+** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
 */
 #define SQLITE_OK           0   /* Successful result */
 /* beginning-of-error-codes */
@@ -437,10 +410,10 @@ int sqlite3_exec(
 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
-#define SQLITE_NOTFOUND    12   /* NOT USED. Table or record not found */
+#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
 #define SQLITE_FULL        13   /* Insertion failed because database is full */
 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
-#define SQLITE_PROTOCOL    15   /* NOT USED. Database lock protocol error */
+#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
 #define SQLITE_EMPTY       16   /* Database is empty */
 #define SQLITE_SCHEMA      17   /* The database schema changed */
 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
@@ -457,7 +430,7 @@ int sqlite3_exec(
 /* end-of-error-codes */
 
 /*
-** CAPI3REF: Extended Result Codes {H10220} <S10700>
+** CAPI3REF: Extended Result Codes
 ** KEYWORDS: {extended error code} {extended error codes}
 ** KEYWORDS: {extended result code} {extended result codes}
 **
@@ -478,19 +451,6 @@ int sqlite3_exec(
 **
 ** The SQLITE_OK result code will never be extended.  It will always
 ** be exactly zero.
-**
-** INVARIANTS:
-**
-** {H10223} The symbolic name for an extended result code shall contains
-**          a related primary result code as a prefix.
-**
-** {H10224} Primary result code names shall contain a single "_" character.
-**
-** {H10225} Extended result code names shall contain two or more "_" characters.
-**
-** {H10226} The numeric value of an extended result code shall contain the
-**          numeric value of its corresponding primary result code in
-**          its least significant 8 bits.
 */
 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
@@ -509,35 +469,55 @@ int sqlite3_exec(
 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
+#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
+#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
+#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
+#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
+#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
+#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
+#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
+#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
+#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
+#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
+#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
+#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
+#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
 
 /*
-** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700>
+** CAPI3REF: Flags For File Open Operations
 **
 ** These bit values are intended for use in the
 ** 3rd parameter to the [sqlite3_open_v2()] interface and
-** in the 4th parameter to the xOpen method of the
-** [sqlite3_vfs] object.
+** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
 */
-#define SQLITE_OPEN_READONLY         0x00000001
-#define SQLITE_OPEN_READWRITE        0x00000002
-#define SQLITE_OPEN_CREATE           0x00000004
-#define SQLITE_OPEN_DELETEONCLOSE    0x00000008
-#define SQLITE_OPEN_EXCLUSIVE        0x00000010
-#define SQLITE_OPEN_MAIN_DB          0x00000100
-#define SQLITE_OPEN_TEMP_DB          0x00000200
-#define SQLITE_OPEN_TRANSIENT_DB     0x00000400
-#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800
-#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000
-#define SQLITE_OPEN_SUBJOURNAL       0x00002000
-#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000
-#define SQLITE_OPEN_NOMUTEX          0x00008000
-#define SQLITE_OPEN_FULLMUTEX        0x00010000
+#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
+#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
+#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
+#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
+#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
+#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
+#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
+#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
+#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
+#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
+#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
+
+/* Reserved:                         0x00F00000 */
 
 /*
-** CAPI3REF: Device Characteristics {H10240} <H11120>
+** CAPI3REF: Device Characteristics
 **
-** The xDeviceCapabilities method of the [sqlite3_io_methods]
-** object returns an integer which is a vector of the these
+** The xDeviceCharacteristics method of the [sqlite3_io_methods]
+** object returns an integer which is a vector of these
 ** bit values expressing I/O characteristics of the mass storage
 ** device that holds the file that the [sqlite3_io_methods]
 ** refers to.
@@ -551,22 +531,28 @@ int sqlite3_exec(
 ** first then the size of the file is extended, never the other
 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
 ** information is written to disk in the same order as calls
-** to xWrite().
+** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
+** after reboot following a crash or power loss, the only bytes in a
+** file that were written at the application level might have changed
+** and that adjacent bytes, even bytes within the same sector are
+** guaranteed to be unchanged.
 */
-#define SQLITE_IOCAP_ATOMIC          0x00000001
-#define SQLITE_IOCAP_ATOMIC512       0x00000002
-#define SQLITE_IOCAP_ATOMIC1K        0x00000004
-#define SQLITE_IOCAP_ATOMIC2K        0x00000008
-#define SQLITE_IOCAP_ATOMIC4K        0x00000010
-#define SQLITE_IOCAP_ATOMIC8K        0x00000020
-#define SQLITE_IOCAP_ATOMIC16K       0x00000040
-#define SQLITE_IOCAP_ATOMIC32K       0x00000080
-#define SQLITE_IOCAP_ATOMIC64K       0x00000100
-#define SQLITE_IOCAP_SAFE_APPEND     0x00000200
-#define SQLITE_IOCAP_SEQUENTIAL      0x00000400
+#define SQLITE_IOCAP_ATOMIC                 0x00000001
+#define SQLITE_IOCAP_ATOMIC512              0x00000002
+#define SQLITE_IOCAP_ATOMIC1K               0x00000004
+#define SQLITE_IOCAP_ATOMIC2K               0x00000008
+#define SQLITE_IOCAP_ATOMIC4K               0x00000010
+#define SQLITE_IOCAP_ATOMIC8K               0x00000020
+#define SQLITE_IOCAP_ATOMIC16K              0x00000040
+#define SQLITE_IOCAP_ATOMIC32K              0x00000080
+#define SQLITE_IOCAP_ATOMIC64K              0x00000100
+#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
+#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
+#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
+#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
 
 /*
-** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310>
+** CAPI3REF: File Locking Levels
 **
 ** SQLite uses one of these integer values as the second
 ** argument to calls it makes to the xLock() and xUnlock() methods
@@ -579,7 +565,7 @@ int sqlite3_exec(
 #define SQLITE_LOCK_EXCLUSIVE     4
 
 /*
-** CAPI3REF: Synchronization Type Flags {H10260} <H11120>
+** CAPI3REF: Synchronization Type Flags
 **
 ** When SQLite invokes the xSync() method of an
 ** [sqlite3_io_methods] object it uses a combination of
@@ -587,19 +573,33 @@ int sqlite3_exec(
 **
 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
 ** sync operation only needs to flush data to mass storage.  Inode
-** information need not be flushed. The SQLITE_SYNC_NORMAL flag means
-** to use normal fsync() semantics. The SQLITE_SYNC_FULL flag means
+** information need not be flushed. If the lower four bits of the flag
+** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
+** If the lower four bits equal SQLITE_SYNC_FULL, that means
 ** to use Mac OS X style fullsync instead of fsync().
+**
+** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
+** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
+** settings.  The [synchronous pragma] determines when calls to the
+** xSync VFS method occur and applies uniformly across all platforms.
+** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
+** energetic or rigorous or forceful the sync operations are and
+** only make a difference on Mac OSX for the default SQLite code.
+** (Third-party VFS implementations might also make the distinction
+** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
+** operating systems natively supported by SQLite, only Mac OSX
+** cares about the difference.)
 */
 #define SQLITE_SYNC_NORMAL        0x00002
 #define SQLITE_SYNC_FULL          0x00003
 #define SQLITE_SYNC_DATAONLY      0x00010
 
 /*
-** CAPI3REF: OS Interface Open File Handle {H11110} <S20110>
+** CAPI3REF: OS Interface Open File Handle
 **
-** An [sqlite3_file] object represents an open file in the OS
-** interface layer.  Individual OS interface implementations will
+** An [sqlite3_file] object represents an open file in the 
+** [sqlite3_vfs | OS interface layer].  Individual OS interface
+** implementations will
 ** want to subclass this object by appending additional fields
 ** for their own use.  The pMethods entry is a pointer to an
 ** [sqlite3_io_methods] object that defines methods for performing
@@ -611,14 +611,21 @@ struct sqlite3_file {
 };
 
 /*
-** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110>
+** CAPI3REF: OS Interface File Virtual Methods Object
 **
-** Every file opened by the [sqlite3_vfs] xOpen method populates an
+** Every file opened by the [sqlite3_vfs.xOpen] method populates an
 ** [sqlite3_file] object (or, more commonly, a subclass of the
 ** [sqlite3_file] object) with a pointer to an instance of this object.
 ** This object defines the methods used to perform various operations
 ** against the open file represented by the [sqlite3_file] object.
 **
+** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 
+** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
+** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
+** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
+** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
+** to NULL.
+**
 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
@@ -651,7 +658,9 @@ struct sqlite3_file {
 ** core reserves all opcodes less than 100 for its own use.
 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
 ** Applications that define a custom xFileControl method should use opcodes
-** greater than 100 to avoid conflicts.
+** greater than 100 to avoid conflicts.  VFS implementations should
+** return [SQLITE_NOTFOUND] for file control opcodes that they do not
+** recognize.
 **
 ** The xSectorSize() method returns the sector size of the
 ** device that underlies the file.  The sector size is the
@@ -706,11 +715,17 @@ struct sqlite3_io_methods {
   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
   int (*xSectorSize)(sqlite3_file*);
   int (*xDeviceCharacteristics)(sqlite3_file*);
+  /* Methods above are valid for version 1 */
+  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
+  void (*xShmBarrier)(sqlite3_file*);
+  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
+  /* Methods above are valid for version 2 */
   /* Additional methods may be added in future releases */
 };
 
 /*
-** CAPI3REF: Standard File Control Opcodes {H11310} <S30800>
+** CAPI3REF: Standard File Control Opcodes
 **
 ** These integer constants are opcodes for the xFileControl method
 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
@@ -723,14 +738,142 @@ struct sqlite3_io_methods {
 ** into an integer that the pArg argument points to. This capability
 ** is used during testing and only needs to be supported when SQLITE_TEST
 ** is defined.
+** <ul>
+** <li>[[SQLITE_FCNTL_SIZE_HINT]]
+** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
+** layer a hint of how large the database file will grow to be during the
+** current transaction.  This hint is not guaranteed to be accurate but it
+** is often close.  The underlying VFS might choose to preallocate database
+** file space based on this hint in order to help writes to the database
+** file run faster.
+**
+** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
+** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
+** extends and truncates the database file in chunks of a size specified
+** by the user. The fourth argument to [sqlite3_file_control()] should 
+** point to an integer (type int) containing the new chunk-size to use
+** for the nominated database. Allocating database file space in large
+** chunks (say 1MB at a time), may reduce file-system fragmentation and
+** improve performance on some systems.
+**
+** <li>[[SQLITE_FCNTL_FILE_POINTER]]
+** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with a particular database
+** connection.  See the [sqlite3_file_control()] documentation for
+** additional information.
+**
+** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
+** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
+** SQLite and sent to all VFSes in place of a call to the xSync method
+** when the database connection has [PRAGMA synchronous] set to OFF.)^
+** Some specialized VFSes need this signal in order to operate correctly
+** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 
+** VFSes do not need this signal and should silently ignore this opcode.
+** Applications should not call [sqlite3_file_control()] with this
+** opcode as doing so may disrupt the operation of the specialized VFSes
+** that do require it.  
+**
+** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
+** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
+** retry counts and intervals for certain disk I/O operations for the
+** windows [VFS] in order to provide robustness in the presence of
+** anti-virus programs.  By default, the windows VFS will retry file read,
+** file write, and file delete operations up to 10 times, with a delay
+** of 25 milliseconds before the first retry and with the delay increasing
+** by an additional 25 milliseconds with each subsequent retry.  This
+** opcode allows these two values (10 retries and 25 milliseconds of delay)
+** to be adjusted.  The values are changed for all database connections
+** within the same process.  The argument is a pointer to an array of two
+** integers where the first integer i the new retry count and the second
+** integer is the delay.  If either integer is negative, then the setting
+** is not changed but instead the prior value of that setting is written
+** into the array entry, allowing the current retry settings to be
+** interrogated.  The zDbName parameter is ignored.
+**
+** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
+** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
+** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
+** write ahead log and shared memory files used for transaction control
+** are automatically deleted when the latest connection to the database
+** closes.  Setting persistent WAL mode causes those files to persist after
+** close.  Persisting the files is useful when other processes that do not
+** have write permission on the directory containing the database file want
+** to read the database file, as the WAL and shared memory files must exist
+** in order for the database to be readable.  The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
+** WAL mode.  If the integer is -1, then it is overwritten with the current
+** WAL persistence setting.
+**
+** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
+** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
+** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
+** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
+** xDeviceCharacteristics methods. The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
+** mode.  If the integer is -1, then it is overwritten with the current
+** zero-damage mode setting.
+**
+** <li>[[SQLITE_FCNTL_OVERWRITE]]
+** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
+** a write transaction to indicate that, unless it is rolled back for some
+** reason, the entire database file will be overwritten by the current 
+** transaction. This is used by VACUUM operations.
+**
+** <li>[[SQLITE_FCNTL_VFSNAME]]
+** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
+** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
+** final bottom-level VFS are written into memory obtained from 
+** [sqlite3_malloc()] and the result is stored in the char* variable
+** that the fourth parameter of [sqlite3_file_control()] points to.
+** The caller is responsible for freeing the memory when done.  As with
+** all file-control actions, there is no guarantee that this will actually
+** do anything.  Callers should initialize the char* variable to a NULL
+** pointer in case this file-control is not implemented.  This file-control
+** is intended for diagnostic use only.
+**
+** <li>[[SQLITE_FCNTL_PRAGMA]]
+** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 
+** file control is sent to the open [sqlite3_file] object corresponding
+** to the database file to which the pragma statement refers. ^The argument
+** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
+** pointers to strings (char**) in which the second element of the array
+** is the name of the pragma and the third element is the argument to the
+** pragma or NULL if the pragma has no argument.  ^The handler for an
+** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
+** of the char** argument point to a string obtained from [sqlite3_mprintf()]
+** or the equivalent and that string will become the result of the pragma or
+** the error message if the pragma fails. ^If the
+** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 
+** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
+** file control returns [SQLITE_OK], then the parser assumes that the
+** VFS has handled the PRAGMA itself and the parser generates a no-op
+** prepared statement.  ^If the [SQLITE_FCNTL_PRAGMA] file control returns
+** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
+** that the VFS encountered an error while handling the [PRAGMA] and the
+** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
+** file control occurs at the beginning of pragma statement analysis and so
+** it is able to override built-in [PRAGMA] statements.
+** </ul>
 */
-#define SQLITE_FCNTL_LOCKSTATE        1
-#define SQLITE_GET_LOCKPROXYFILE      2
-#define SQLITE_SET_LOCKPROXYFILE      3
-#define SQLITE_LAST_ERRNO             4
+#define SQLITE_FCNTL_LOCKSTATE               1
+#define SQLITE_GET_LOCKPROXYFILE             2
+#define SQLITE_SET_LOCKPROXYFILE             3
+#define SQLITE_LAST_ERRNO                    4
+#define SQLITE_FCNTL_SIZE_HINT               5
+#define SQLITE_FCNTL_CHUNK_SIZE              6
+#define SQLITE_FCNTL_FILE_POINTER            7
+#define SQLITE_FCNTL_SYNC_OMITTED            8
+#define SQLITE_FCNTL_WIN32_AV_RETRY          9
+#define SQLITE_FCNTL_PERSIST_WAL            10
+#define SQLITE_FCNTL_OVERWRITE              11
+#define SQLITE_FCNTL_VFSNAME                12
+#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
+#define SQLITE_FCNTL_PRAGMA                 14
 
 /*
-** CAPI3REF: Mutex Handle {H17110} <S20130>
+** CAPI3REF: Mutex Handle
 **
 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
 ** abstract type for a mutex object.  The SQLite core never looks
@@ -742,11 +885,12 @@ struct sqlite3_io_methods {
 typedef struct sqlite3_mutex sqlite3_mutex;
 
 /*
-** CAPI3REF: OS Interface Object {H11140} <S20100>
+** CAPI3REF: OS Interface Object
 **
 ** An instance of the sqlite3_vfs object defines the interface between
 ** the SQLite core and the underlying operating system.  The "vfs"
-** in the name of the object stands for "virtual file system".
+** in the name of the object stands for "virtual file system".  See
+** the [VFS | VFS documentation] for further information.
 **
 ** The value of the iVersion field is initially 1 but may be larger in
 ** future versions of SQLite.  Additional fields may be appended to this
@@ -775,15 +919,20 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** The zName field holds the name of the VFS module.  The name must
 ** be unique across all VFS modules.
 **
-** SQLite will guarantee that the zFilename parameter to xOpen
+** [[sqlite3_vfs.xOpen]]
+** ^SQLite guarantees that the zFilename parameter to xOpen
 ** is either a NULL pointer or string obtained
-** from xFullPathname().  SQLite further guarantees that
+** from xFullPathname() with an optional suffix added.
+** ^If a suffix is added to the zFilename parameter, it will
+** consist of a single "-" character followed by no more than
+** 11 alphanumeric and/or "-" characters.
+** ^SQLite further guarantees that
 ** the string will be valid and unchanged until xClose() is
-** called. Because of the previous sentense,
+** called. Because of the previous sentence,
 ** the [sqlite3_file] can safely store a pointer to the
 ** filename if it needs to remember the filename for some reason.
-** If the zFilename parameter is xOpen is a NULL pointer then xOpen
-** must invite its own temporary name for the file.  Whenever the 
+** If the zFilename parameter to xOpen is a NULL pointer then xOpen
+** must invent its own temporary name for the file.  ^Whenever the 
 ** xFilename parameter is NULL it will also be the case that the
 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
 **
@@ -794,7 +943,7 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** If xOpen() opens a file read-only then it sets *pOutFlags to
 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
 **
-** SQLite will also add one of the following flags to the xOpen()
+** ^(SQLite will also add one of the following flags to the xOpen()
 ** call, depending on the object being opened:
 **
 ** <ul>
@@ -805,7 +954,8 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
-** </ul>
+** <li>  [SQLITE_OPEN_WAL]
+** </ul>)^
 **
 ** The file I/O implementation can use the object type flags to
 ** change the way it deals with files.  For example, an application
@@ -824,45 +974,77 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** </ul>
 **
 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
-** deleted when it is closed.  The [SQLITE_OPEN_DELETEONCLOSE]
-** will be set for TEMP  databases, journals and for subjournals.
+** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
+** will be set for TEMP databases and their journals, transient
+** databases, and subjournals.
 **
-** The [SQLITE_OPEN_EXCLUSIVE] flag means the file should be opened
-** for exclusive access.  This flag is set for all files except
-** for the main database file.
+** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
+** with the [SQLITE_OPEN_CREATE] flag, which are both directly
+** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
+** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 
+** SQLITE_OPEN_CREATE, is used to indicate that file should always
+** be created, and that it is an error if it already exists.
+** It is <i>not</i> used to indicate the file should be opened 
+** for exclusive access.
 **
-** At least szOsFile bytes of memory are allocated by SQLite
+** ^At least szOsFile bytes of memory are allocated by SQLite
 ** to hold the  [sqlite3_file] structure passed as the third
 ** argument to xOpen.  The xOpen method does not have to
-** allocate the structure; it should just fill it in.
+** allocate the structure; it should just fill it in.  Note that
+** the xOpen method must set the sqlite3_file.pMethods to either
+** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
+** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
+** element will be valid after xOpen returns regardless of the success
+** or failure of the xOpen call.
 **
-** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
+** [[sqlite3_vfs.xAccess]]
+** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
 ** to test whether a file is at least readable.   The file can be a
 ** directory.
 **
-** SQLite will always allocate at least mxPathname+1 bytes for the
+** ^SQLite will always allocate at least mxPathname+1 bytes for the
 ** output buffer xFullPathname.  The exact size of the output buffer
 ** is also passed as a parameter to both  methods. If the output buffer
 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
 ** handled as a fatal error by SQLite, vfs implementations should endeavor
 ** to prevent this by setting mxPathname to a sufficiently large value.
 **
-** The xRandomness(), xSleep(), and xCurrentTime() interfaces
-** are not strictly a part of the filesystem, but they are
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
 ** included in the VFS structure for completeness.
 ** The xRandomness() function attempts to return nBytes bytes
 ** of good-quality randomness into zOut.  The return value is
 ** the actual number of bytes of randomness obtained.
 ** The xSleep() method causes the calling thread to sleep for at
-** least the number of microseconds given.  The xCurrentTime()
-** method returns a Julian Day Number for the current date and time.
+** least the number of microseconds given.  ^The xCurrentTime()
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multiplied by 86400000 (the number of milliseconds in 
+** a 24-hour day).  
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or 
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
 **
+** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
+** are not used by the SQLite core.  These optional interfaces are provided
+** by some VFSes to facilitate testing of the VFS code. By overriding 
+** system calls with functions under its control, a test program can
+** simulate faults and error conditions that would otherwise be difficult
+** or impossible to induce.  The set of system calls that can be overridden
+** varies from one VFS to another, and from one version of the same VFS to the
+** next.  Applications that use these interfaces must be prepared for any
+** or all of these interfaces to be NULL or for their behavior to change
+** from one release to the next.  Applications must not attempt to access
+** any of these methods if the iVersion of the VFS is less than 3.
 */
 typedef struct sqlite3_vfs sqlite3_vfs;
+typedef void (*sqlite3_syscall_ptr)(void);
 struct sqlite3_vfs {
-  int iVersion;            /* Structure version number */
+  int iVersion;            /* Structure version number (currently 3) */
   int szOsFile;            /* Size of subclassed sqlite3_file */
   int mxPathname;          /* Maximum file pathname length */
   sqlite3_vfs *pNext;      /* Next registered VFS */
@@ -881,56 +1063,130 @@ struct sqlite3_vfs {
   int (*xSleep)(sqlite3_vfs*, int microseconds);
   int (*xCurrentTime)(sqlite3_vfs*, double*);
   int (*xGetLastError)(sqlite3_vfs*, int, char *);
-  /* New fields may be appended in figure versions.  The iVersion
-  ** value will increment whenever this happens. */
+  /*
+  ** The methods above are in version 1 of the sqlite_vfs object
+  ** definition.  Those that follow are added in version 2 or later
+  */
+  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
+  /*
+  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
+  ** Those below are for version 3 and greater.
+  */
+  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
+  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
+  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
+  /*
+  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
+  ** New fields may be appended in figure versions.  The iVersion
+  ** value will increment whenever this happens. 
+  */
 };
 
 /*
-** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140>
+** CAPI3REF: Flags for the xAccess VFS method
 **
 ** These integer constants can be used as the third parameter to
-** the xAccess method of an [sqlite3_vfs] object. {END}  They determine
+** the xAccess method of an [sqlite3_vfs] object.  They determine
 ** what kind of permissions the xAccess method is looking for.
 ** With SQLITE_ACCESS_EXISTS, the xAccess method
 ** simply checks whether the file exists.
 ** With SQLITE_ACCESS_READWRITE, the xAccess method
-** checks whether the file is both readable and writable.
+** checks whether the named directory is both readable and writable
+** (in other words, if files can be added, removed, and renamed within
+** the directory).
+** The SQLITE_ACCESS_READWRITE constant is currently used only by the
+** [temp_store_directory pragma], though this could change in a future
+** release of SQLite.
 ** With SQLITE_ACCESS_READ, the xAccess method
-** checks whether the file is readable.
+** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
+** currently unused, though it might be used in a future release of
+** SQLite.
 */
 #define SQLITE_ACCESS_EXISTS    0
-#define SQLITE_ACCESS_READWRITE 1
-#define SQLITE_ACCESS_READ      2
+#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
+#define SQLITE_ACCESS_READ      2   /* Unused */
 
 /*
-** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100>
+** CAPI3REF: Flags for the xShmLock VFS method
 **
-** The sqlite3_initialize() routine initializes the
-** SQLite library.  The sqlite3_shutdown() routine
+** These integer constants define the various locking operations
+** allowed by the xShmLock method of [sqlite3_io_methods].  The
+** following are the only legal combinations of flags to the
+** xShmLock method:
+**
+** <ul>
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
+** </ul>
+**
+** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
+** was given no the corresponding lock.  
+**
+** The xShmLock method can transition between unlocked and SHARED or
+** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
+** and EXCLUSIVE.
+*/
+#define SQLITE_SHM_UNLOCK       1
+#define SQLITE_SHM_LOCK         2
+#define SQLITE_SHM_SHARED       4
+#define SQLITE_SHM_EXCLUSIVE    8
+
+/*
+** CAPI3REF: Maximum xShmLock index
+**
+** The xShmLock method on [sqlite3_io_methods] may use values
+** between 0 and this upper bound as its "offset" argument.
+** The SQLite core will never attempt to acquire or release a
+** lock outside of this range
+*/
+#define SQLITE_SHM_NLOCK        8
+
+
+/*
+** CAPI3REF: Initialize The SQLite Library
+**
+** ^The sqlite3_initialize() routine initializes the
+** SQLite library.  ^The sqlite3_shutdown() routine
 ** deallocates any resources that were allocated by sqlite3_initialize().
+** These routines are designed to aid in process initialization and
+** shutdown on embedded systems.  Workstation applications using
+** SQLite normally do not need to invoke either of these routines.
 **
 ** A call to sqlite3_initialize() is an "effective" call if it is
 ** the first time sqlite3_initialize() is invoked during the lifetime of
 ** the process, or if it is the first time sqlite3_initialize() is invoked
-** following a call to sqlite3_shutdown().  Only an effective call
+** following a call to sqlite3_shutdown().  ^(Only an effective call
 ** of sqlite3_initialize() does any initialization.  All other calls
-** are harmless no-ops.
+** are harmless no-ops.)^
 **
-** Among other things, sqlite3_initialize() shall invoke
-** sqlite3_os_init().  Similarly, sqlite3_shutdown()
-** shall invoke sqlite3_os_end().
+** A call to sqlite3_shutdown() is an "effective" call if it is the first
+** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
+** an effective call to sqlite3_shutdown() does any deinitialization.
+** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
 **
-** The sqlite3_initialize() routine returns [SQLITE_OK] on success.
-** If for some reason, sqlite3_initialize() is unable to initialize
+** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
+** is not.  The sqlite3_shutdown() interface must only be called from a
+** single thread.  All open [database connections] must be closed and all
+** other SQLite resources must be deallocated prior to invoking
+** sqlite3_shutdown().
+**
+** Among other things, ^sqlite3_initialize() will invoke
+** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
+** will invoke sqlite3_os_end().
+**
+** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
+** ^If for some reason, sqlite3_initialize() is unable to initialize
 ** the library (perhaps it is unable to allocate a needed resource such
 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
 **
-** The sqlite3_initialize() routine is called internally by many other
+** ^The sqlite3_initialize() routine is called internally by many other
 ** SQLite interfaces so that an application usually does not need to
 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
 ** calls sqlite3_initialize() so the SQLite library will be automatically
 ** initialized when [sqlite3_open()] is called if it has not be initialized
-** already.  However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
+** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
 ** compile-time option, then the automatic calls to sqlite3_initialize()
 ** are omitted and the application must call sqlite3_initialize() directly
 ** prior to using any other SQLite interface.  For maximum portability,
@@ -954,22 +1210,22 @@ struct sqlite3_vfs {
 ** interface is called automatically by sqlite3_initialize() and
 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
 ** implementations for sqlite3_os_init() and sqlite3_os_end()
-** are built into SQLite when it is compiled for unix, windows, or os/2.
-** When built for other platforms (using the [SQLITE_OS_OTHER=1] compile-time
+** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
+** When [custom builds | built for other platforms]
+** (using the [SQLITE_OS_OTHER=1] compile-time
 ** option) the application must supply a suitable implementation for
 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
 ** implementation of sqlite3_os_init() or sqlite3_os_end()
 ** must return [SQLITE_OK] on success and some other [error code] upon
 ** failure.
 */
-int sqlite3_initialize(void);
-int sqlite3_shutdown(void);
-int sqlite3_os_init(void);
-int sqlite3_os_end(void);
+SQLITE_API int sqlite3_initialize(void);
+SQLITE_API int sqlite3_shutdown(void);
+SQLITE_API int sqlite3_os_init(void);
+SQLITE_API int sqlite3_os_end(void);
 
 /*
-** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200>
-** EXPERIMENTAL
+** CAPI3REF: Configuring The SQLite Library
 **
 ** The sqlite3_config() interface is used to make global configuration
 ** changes to SQLite in order to tune SQLite to the specific needs of
@@ -982,166 +1238,43 @@ int sqlite3_os_end(void);
 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
 ** may only be invoked prior to library initialization using
 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
-** Note, however, that sqlite3_config() can be called as part of the
+** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
+** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
+** Note, however, that ^sqlite3_config() can be called as part of the
 ** implementation of an application-defined [sqlite3_os_init()].
 **
 ** The first argument to sqlite3_config() is an integer
-** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
+** [configuration option] that determines
 ** what property of SQLite is to be configured.  Subsequent arguments
-** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
+** vary depending on the [configuration option]
 ** in the first argument.
 **
-** When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
-** If the option is unknown or SQLite is unable to set the option
+** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
+** ^If the option is unknown or SQLite is unable to set the option
 ** then this routine returns a non-zero [error code].
-**
-** INVARIANTS:
-**
-** {H14103} A successful invocation of [sqlite3_config()] shall return
-**          [SQLITE_OK].
-**
-** {H14106} The [sqlite3_config()] interface shall return [SQLITE_MISUSE]
-**          if it is invoked in between calls to [sqlite3_initialize()] and
-**          [sqlite3_shutdown()].
-**
-** {H14120} A successful call to [sqlite3_config]([SQLITE_CONFIG_SINGLETHREAD])
-**          shall set the default [threading mode] to Single-thread.
-**
-** {H14123} A successful call to [sqlite3_config]([SQLITE_CONFIG_MULTITHREAD])
-**          shall set the default [threading mode] to Multi-thread.
-**
-** {H14126} A successful call to [sqlite3_config]([SQLITE_CONFIG_SERIALIZED])
-**          shall set the default [threading mode] to Serialized.
-**
-** {H14129} A successful call to [sqlite3_config]([SQLITE_CONFIG_MUTEX],X)
-**          where X is a pointer to an initialized [sqlite3_mutex_methods]
-**          object shall cause all subsequent mutex operations performed
-**          by SQLite to use the mutex methods that were present in X
-**          during the call to [sqlite3_config()].
-**
-** {H14132} A successful call to [sqlite3_config]([SQLITE_CONFIG_GETMUTEX],X)
-**          where X is a pointer to an [sqlite3_mutex_methods] object 
-**          shall overwrite the content of [sqlite3_mutex_methods] object
-**          with the mutex methods currently in use by SQLite.
-**
-** {H14135} A successful call to [sqlite3_config]([SQLITE_CONFIG_MALLOC],M)
-**          where M is a pointer to an initialized [sqlite3_mem_methods]
-**          object shall cause all subsequent memory allocation operations
-**          performed by SQLite to use the methods that were present in 
-**          M during the call to [sqlite3_config()].
-**
-** {H14138} A successful call to [sqlite3_config]([SQLITE_CONFIG_GETMALLOC],M)
-**          where M is a pointer to an [sqlite3_mem_methods] object shall
-**          overwrite the content of [sqlite3_mem_methods] object with 
-**          the memory allocation methods currently in use by
-**          SQLite.
-**
-** {H14141} A successful call to [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],1)
-**          shall enable the memory allocation status collection logic.
-**
-** {H14144} A successful call to [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],0)
-**          shall disable the memory allocation status collection logic.
-**
-** {H14147} The memory allocation status collection logic shall be
-**          enabled by default.
-**
-** {H14150} A successful call to [sqlite3_config]([SQLITE_CONFIG_SCRATCH],S,Z,N)
-**          where Z and N are non-negative integers and 
-**          S is a pointer to an aligned memory buffer not less than
-**          Z*N bytes in size shall cause S to be used by the
-**          [scratch memory allocator] for as many as N simulataneous
-**          allocations each of size (Z & ~7).
-**
-** {H14153} A successful call to [sqlite3_config]([SQLITE_CONFIG_SCRATCH],S,Z,N)
-**          where S is a NULL pointer shall disable the
-**          [scratch memory allocator].
-**
-** {H14156} A successful call to
-**          [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],S,Z,N)
-**          where Z and N are non-negative integers and 
-**          S is a pointer to an aligned memory buffer not less than
-**          Z*N bytes in size shall cause S to be used by the
-**          [pagecache memory allocator] for as many as N simulataneous
-**          allocations each of size (Z & ~7).
-**
-** {H14159} A successful call to
-**          [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],S,Z,N)
-**          where S is a NULL pointer shall disable the
-**          [pagecache memory allocator].
-**
-** {H14162} A successful call to [sqlite3_config]([SQLITE_CONFIG_HEAP],H,Z,N)
-**          where Z and N are non-negative integers and 
-**          H is a pointer to an aligned memory buffer not less than
-**          Z bytes in size shall enable the [memsys5] memory allocator
-**          and cause it to use buffer S as its memory source and to use
-**          a minimum allocation size of N.
-**
-** {H14165} A successful call to [sqlite3_config]([SQLITE_CONFIG_HEAP],H,Z,N)
-**          where H is a NULL pointer shall disable the
-**          [memsys5] memory allocator.
-**
-** {H14168} A successful call to [sqlite3_config]([SQLITE_CONFIG_LOOKASIDE],Z,N)
-**          shall cause the default [lookaside memory allocator] configuration
-**          for new [database connections] to be N slots of Z bytes each.
 */
-SQLITE_EXPERIMENTAL int sqlite3_config(int, ...);
+SQLITE_API int sqlite3_config(int, ...);
 
 /*
-** CAPI3REF: Configure database connections  {H14200} <S20000>
-** EXPERIMENTAL
+** CAPI3REF: Configure database connections
 **
 ** The sqlite3_db_config() interface is used to make configuration
 ** changes to a [database connection].  The interface is similar to
 ** [sqlite3_config()] except that the changes apply to a single
-** [database connection] (specified in the first argument).  The
-** sqlite3_db_config() interface can only be used immediately after
-** the database connection is created using [sqlite3_open()],
-** [sqlite3_open16()], or [sqlite3_open_v2()].  
+** [database connection] (specified in the first argument).
 **
 ** The second argument to sqlite3_db_config(D,V,...)  is the
-** configuration verb - an integer code that indicates what
-** aspect of the [database connection] is being configured.
-** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE].
-** New verbs are likely to be added in future releases of SQLite.
-** Additional arguments depend on the verb.
-**
-** INVARIANTS:
-**
-** {H14203} A call to [sqlite3_db_config(D,V,...)] shall return [SQLITE_OK]
-**          if and only if the call is successful.
-**
-** {H14206} If one or more slots of the [lookaside memory allocator] for
-**          [database connection] D are in use, then a call to
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],...) shall
-**          fail with an [SQLITE_BUSY] return code.
-**
-** {H14209} A successful call to 
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],B,Z,N) where
-**          D is an open [database connection] and Z and N are positive
-**          integers and B is an aligned buffer at least Z*N bytes in size
-**          shall cause the [lookaside memory allocator] for D to use buffer B 
-**          with N slots of Z bytes each.
-**
-** {H14212} A successful call to 
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],B,Z,N) where
-**          D is an open [database connection] and Z and N are positive
-**          integers and B is NULL pointer shall cause the
-**          [lookaside memory allocator] for D to a obtain Z*N byte buffer
-**          from the primary memory allocator and use that buffer
-**          with N lookaside slots of Z bytes each.
-**
-** {H14215} A successful call to 
-**          [sqlite3_db_config](D,[SQLITE_DBCONFIG_LOOKASIDE],B,Z,N) where
-**          D is an open [database connection] and Z and N are zero shall
-**          disable the [lookaside memory allocator] for D.
-**
+** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 
+** that indicates what aspect of the [database connection] is being configured.
+** Subsequent arguments vary depending on the configuration verb.
 **
+** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
+** the call is considered successful.
 */
-SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
+SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
 
 /*
-** CAPI3REF: Memory Allocation Routines {H10155} <S20120>
-** EXPERIMENTAL
+** CAPI3REF: Memory Allocation Routines
 **
 ** An instance of this object defines the interface between SQLite
 ** and low-level memory allocation routines.
@@ -1149,13 +1282,15 @@ SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** This object is used in only one place in the SQLite interface.
 ** A pointer to an instance of this object is the argument to
 ** [sqlite3_config()] when the configuration option is
-** [SQLITE_CONFIG_MALLOC].  By creating an instance of this object
-** and passing it to [sqlite3_config()] during configuration, an
-** application can specify an alternative memory allocation subsystem
-** for SQLite to use for all of its dynamic memory needs.
+** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].  
+** By creating an instance of this object
+** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
+** during configuration, an application can specify an alternative
+** memory allocation subsystem for SQLite to use for all of its
+** dynamic memory needs.
 **
-** Note that SQLite comes with a built-in memory allocator that is
-** perfectly adequate for the overwhelming majority of applications
+** Note that SQLite comes with several [built-in memory allocators]
+** that are perfectly adequate for the overwhelming majority of applications
 ** and that this object is only useful to a tiny minority of applications
 ** with specialized memory allocation requirements.  This object is
 ** also used during testing of SQLite in order to specify an alternative
@@ -1163,8 +1298,10 @@ SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** order to verify that SQLite recovers gracefully from such
 ** conditions.
 **
-** The xMalloc, xFree, and xRealloc methods must work like the
-** malloc(), free(), and realloc() functions from the standard library.
+** The xMalloc, xRealloc, and xFree methods must work like the
+** malloc(), realloc() and free() functions from the standard C library.
+** ^SQLite guarantees that the second argument to
+** xRealloc is always a value returned by a prior call to xRoundup.
 **
 ** xSize should return the allocated size of a memory allocation
 ** previously obtained from xMalloc or xRealloc.  The allocated size
@@ -1174,6 +1311,9 @@ SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** a memory allocation given a particular requested size.  Most memory
 ** allocators round up memory allocations at least to the next multiple
 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
+** Every memory allocation request coming in through [sqlite3_malloc()]
+** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0, 
+** that causes the corresponding memory allocation to fail.
 **
 ** The xInit method initializes the memory allocator.  (For example,
 ** it might allocate any require mutexes or initialize internal data
@@ -1181,6 +1321,20 @@ SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
 ** [sqlite3_shutdown()] and should deallocate any resources acquired
 ** by xInit.  The pAppData pointer is used as the only parameter to
 ** xInit and xShutdown.
+**
+** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
+** the xInit method, so the xInit method need not be threadsafe.  The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  For all other methods, SQLite
+** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
+** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
+** it is by default) and so the methods are automatically serialized.
+** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
+** methods must be threadsafe or else make their own arrangements for
+** serialization.
+**
+** SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
 */
 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
 struct sqlite3_mem_methods {
@@ -1195,8 +1349,8 @@ struct sqlite3_mem_methods {
 };
 
 /*
-** CAPI3REF: Configuration Options {H10160} <S20000>
-** EXPERIMENTAL
+** CAPI3REF: Configuration Options
+** KEYWORDS: {configuration option}
 **
 ** These constants are the available integer configuration options that
 ** can be passed as the first argument to the [sqlite3_config()] interface.
@@ -1209,23 +1363,34 @@ struct sqlite3_mem_methods {
 ** is invoked.
 **
 ** <dl>
-** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
-** <dd>There are no arguments to this option.  This option disables
+** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Single-thread.  In other words, it disables
 ** all mutexing and puts SQLite into a mode where it can only be used
-** by a single thread.</dd>
+** by a single thread.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to change the [threading mode] from its default
+** value of Single-thread and so [sqlite3_config()] will return 
+** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
+** configuration option.</dd>
 **
-** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
-** <dd>There are no arguments to this option.  This option disables
+** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Multi-thread.  In other words, it disables
 ** mutexing on [database connection] and [prepared statement] objects.
 ** The application is responsible for serializing access to
 ** [database connections] and [prepared statements].  But other mutexes
 ** are enabled so that SQLite will be safe to use in a multi-threaded
 ** environment as long as no two threads attempt to use the same
-** [database connection] at the same time.  See the [threading mode]
-** documentation for additional information.</dd>
+** [database connection] at the same time.  ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Multi-thread [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
 **
-** <dt>SQLITE_CONFIG_SERIALIZED</dt>
-** <dd>There are no arguments to this option.  This option enables
+** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Serialized. In other words, this option enables
 ** all mutexes including the recursive
 ** mutexes on [database connection] and [prepared statement] objects.
 ** In this mode (which is the default when SQLite is compiled with
@@ -1233,112 +1398,179 @@ struct sqlite3_mem_methods {
 ** to [database connections] and [prepared statements] so that the
 ** application is free to use the same [database connection] or the
 ** same [prepared statement] in different threads at the same time.
-** See the [threading mode] documentation for additional information.</dd>
+** ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Serialized [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
 **
-** <dt>SQLITE_CONFIG_MALLOC</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mem_methods] structure.  The argument specifies
 ** alternative low-level memory allocation routines to be used in place of
-** the memory allocation routines built into SQLite.</dd>
+** the memory allocation routines built into SQLite.)^ ^SQLite makes
+** its own private copy of the content of the [sqlite3_mem_methods] structure
+** before the [sqlite3_config()] call returns.</dd>
 **
-** <dt>SQLITE_CONFIG_GETMALLOC</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
-** structure is filled with the currently defined memory allocation routines.
+** structure is filled with the currently defined memory allocation routines.)^
 ** This option can be used to overload the default memory allocation
 ** routines with a wrapper that simulations memory allocation failure or
-** tracks memory usage, for example.</dd>
+** tracks memory usage, for example. </dd>
 **
-** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
-** <dd>This option takes single argument of type int, interpreted as a 
+** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
+** <dd> ^This option takes single argument of type int, interpreted as a 
 ** boolean, which enables or disables the collection of memory allocation 
-** statistics. When disabled, the following SQLite interfaces become 
-** non-operational:
+** statistics. ^(When memory allocation statistics are disabled, the 
+** following SQLite interfaces become non-operational:
 **   <ul>
 **   <li> [sqlite3_memory_used()]
 **   <li> [sqlite3_memory_highwater()]
-**   <li> [sqlite3_soft_heap_limit()]
+**   <li> [sqlite3_soft_heap_limit64()]
 **   <li> [sqlite3_status()]
-**   </ul>
+**   </ul>)^
+** ^Memory allocation statistics are enabled by default unless SQLite is
+** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
+** allocation statistics are disabled by default.
 ** </dd>
 **
-** <dt>SQLITE_CONFIG_SCRATCH</dt>
-** <dd>This option specifies a static memory buffer that SQLite can use for
-** scratch memory.  There are three arguments:  A pointer to the memory, the
-** size of each scratch buffer (sz), and the number of buffers (N).  The sz
-** argument must be a multiple of 16. The sz parameter should be a few bytes
-** larger than the actual scratch space required due internal overhead.
-** The first
-** argument should point to an allocation of at least sz*N bytes of memory.
-** SQLite will use no more than one scratch buffer at once per thread, so
-** N should be set to the expected maximum number of threads.  The sz
-** parameter should be 6 times the size of the largest database page size.
-** Scratch buffers are used as part of the btree balance operation.  If
-** The btree balancer needs additional memory beyond what is provided by
-** scratch buffers or if no scratch buffer space is specified, then SQLite
-** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd>
+** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
+** <dd> ^This option specifies a static memory buffer that SQLite can use for
+** scratch memory.  There are three arguments:  A pointer an 8-byte
+** aligned memory buffer from which the scratch allocations will be
+** drawn, the size of each scratch allocation (sz),
+** and the maximum number of scratch allocations (N).  The sz
+** argument must be a multiple of 16.
+** The first argument must be a pointer to an 8-byte aligned buffer
+** of at least sz*N bytes of memory.
+** ^SQLite will use no more than two scratch buffers per thread.  So
+** N should be set to twice the expected maximum number of threads.
+** ^SQLite will never require a scratch buffer that is more than 6
+** times the database page size. ^If SQLite needs needs additional
+** scratch memory beyond what is provided by this configuration option, then 
+** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
 **
-** <dt>SQLITE_CONFIG_PAGECACHE</dt>
-** <dd>This option specifies a static memory buffer that SQLite can use for
-** the database page cache with the default page cache implemenation.  
+** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
+** <dd> ^This option specifies a static memory buffer that SQLite can use for
+** the database page cache with the default page cache implementation.  
 ** This configuration should not be used if an application-define page
-** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
-** There are three arguments to this option: A pointer to the
+** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
+** There are three arguments to this option: A pointer to 8-byte aligned
 ** memory, the size of each page buffer (sz), and the number of pages (N).
-** The sz argument must be a power of two between 512 and 32768.  The first
+** The sz argument should be the size of the largest database page
+** (a power of two between 512 and 32768) plus a little extra for each
+** page header.  ^The page header size is 20 to 40 bytes depending on
+** the host architecture.  ^It is harmless, apart from the wasted memory,
+** to make sz a little too large.  The first
 ** argument should point to an allocation of at least sz*N bytes of memory.
-** SQLite will use the memory provided by the first argument to satisfy its
-** memory needs for the first N pages that it adds to cache.  If additional
+** ^SQLite will use the memory provided by the first argument to satisfy its
+** memory needs for the first N pages that it adds to cache.  ^If additional
 ** page cache memory is needed beyond what is provided by this option, then
 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
-** The implementation might use one or more of the N buffers to hold 
-** memory accounting information. </dd>
+** The pointer in the first argument must
+** be aligned to an 8-byte boundary or subsequent behavior of SQLite
+** will be undefined.</dd>
 **
-** <dt>SQLITE_CONFIG_HEAP</dt>
-** <dd>This option specifies a static memory buffer that SQLite will use
+** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
+** <dd> ^This option specifies a static memory buffer that SQLite will use
 ** for all of its dynamic memory allocation needs beyond those provided
 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
-** There are three arguments: A pointer to the memory, the number of
-** bytes in the memory buffer, and the minimum allocation size.  If
-** the first pointer (the memory pointer) is NULL, then SQLite reverts
+** There are three arguments: An 8-byte aligned pointer to the memory,
+** the number of bytes in the memory buffer, and the minimum allocation size.
+** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
 ** to using its default memory allocator (the system malloc() implementation),
-** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  If the
+** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
-** allocator is engaged to handle all of SQLites memory allocation needs.</dd>
+** allocator is engaged to handle all of SQLites memory allocation needs.
+** The first pointer (the memory pointer) must be aligned to an 8-byte
+** boundary or subsequent behavior of SQLite will be undefined.
+** The minimum allocation size is capped at 2**12. Reasonable values
+** for the minimum allocation size are 2**5 through 2**8.</dd>
 **
-** <dt>SQLITE_CONFIG_MUTEX</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
 ** alternative low-level mutex routines to be used in place
-** the mutex routines built into SQLite.</dd>
+** the mutex routines built into SQLite.)^  ^SQLite makes a copy of the
+** content of the [sqlite3_mutex_methods] structure before the call to
+** [sqlite3_config()] returns. ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
 **
-** <dt>SQLITE_CONFIG_GETMUTEX</dt>
-** <dd>This option takes a single argument which is a pointer to an
+** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
 ** instance of the [sqlite3_mutex_methods] structure.  The
 ** [sqlite3_mutex_methods]
-** structure is filled with the currently defined mutex routines.
+** structure is filled with the currently defined mutex routines.)^
 ** This option can be used to overload the default mutex allocation
 ** routines with a wrapper used to track mutex usage for performance
-** profiling or testing, for example.</dd>
+** profiling or testing, for example.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
 **
-** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
-** <dd>This option takes two arguments that determine the default
-** memory allcation lookaside optimization.  The first argument is the
+** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
+** <dd> ^(This option takes two arguments that determine the default
+** memory allocation for the lookaside memory allocator on each
+** [database connection].  The first argument is the
 ** size of each lookaside buffer slot and the second is the number of
-** slots allocated to each database connection.</dd>
+** slots allocated to each database connection.)^  ^(This option sets the
+** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
+** verb to [sqlite3_db_config()] can be used to change the lookaside
+** configuration on individual connections.)^ </dd>
 **
-** <dt>SQLITE_CONFIG_PCACHE</dt>
-** <dd>This option takes a single argument which is a pointer to
-** an [sqlite3_pcache_methods] object.  This object specifies the interface
-** to a custom page cache implementation.  SQLite makes a copy of the
+** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
+** <dd> ^(This option takes a single argument which is a pointer to
+** an [sqlite3_pcache_methods2] object.  This object specifies the interface
+** to a custom page cache implementation.)^  ^SQLite makes a copy of the
 ** object and uses it for page cache memory allocations.</dd>
 **
-** <dt>SQLITE_CONFIG_GETPCACHE</dt>
-** <dd>This option takes a single argument which is a pointer to an
-** [sqlite3_pcache_methods] object.  SQLite copies of the current
-** page cache implementation into that object.</dd>
+** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
+** <dd> ^(This option takes a single argument which is a pointer to an
+** [sqlite3_pcache_methods2] object.  SQLite copies of the current
+** page cache implementation into that object.)^ </dd>
 **
+** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
+** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
+** function with a call signature of void(*)(void*,int,const char*), 
+** and a pointer to void. ^If the function pointer is not NULL, it is
+** invoked by [sqlite3_log()] to process each logging event.  ^If the
+** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
+** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
+** passed through as the first parameter to the application-defined logger
+** function whenever that function is invoked.  ^The second parameter to
+** the logger function is a copy of the first parameter to the corresponding
+** [sqlite3_log()] call and is intended to be a [result code] or an
+** [extended result code].  ^The third parameter passed to the logger is
+** log message after formatting via [sqlite3_snprintf()].
+** The SQLite logging interface is not reentrant; the logger function
+** supplied by the application must not invoke any SQLite interface.
+** In a multi-threaded application, the application-defined logger
+** function must be threadsafe. </dd>
+**
+** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
+** <dd> This option takes a single argument of type int. If non-zero, then
+** URI handling is globally enabled. If the parameter is zero, then URI handling
+** is globally disabled. If URI handling is globally enabled, all filenames
+** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
+** specified as part of [ATTACH] commands are interpreted as URIs, regardless
+** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
+** connection is opened. If it is globally disabled, filenames are
+** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
+** database connection is opened. By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** [SQLITE_USE_URI] symbol defined.
+**
+** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
+** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
+** <dd> These options are obsolete and should not be used by new code.
+** They are retained for backwards compatibility but are now no-ops.
 ** </dl>
 */
 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
@@ -1354,12 +1586,15 @@ struct sqlite3_mem_methods {
 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
-#define SQLITE_CONFIG_PCACHE       14  /* sqlite3_pcache_methods* */
-#define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
+#define SQLITE_CONFIG_PCACHE       14  /* no-op */
+#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
+#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
+#define SQLITE_CONFIG_URI          17  /* int */
+#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
 
 /*
-** CAPI3REF: Configuration Options {H10170} <S20000>
-** EXPERIMENTAL
+** CAPI3REF: Database Connection Configuration Options
 **
 ** These constants are the available integer configuration options that
 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
@@ -1367,322 +1602,295 @@ struct sqlite3_mem_methods {
 ** New configuration options may be added in future releases of SQLite.
 ** Existing configuration options might be discontinued.  Applications
 ** should check the return code from [sqlite3_db_config()] to make sure that
-** the call worked.  The [sqlite3_db_config()] interface will return a
+** the call worked.  ^The [sqlite3_db_config()] interface will return a
 ** non-zero [error code] if a discontinued or unsupported configuration option
 ** is invoked.
 **
 ** <dl>
 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
-** <dd>This option takes three additional arguments that determine the 
+** <dd> ^This option takes three additional arguments that determine the 
 ** [lookaside memory allocator] configuration for the [database connection].
-** The first argument (the third parameter to [sqlite3_db_config()] is a
-** pointer to a memory buffer to use for lookaside memory.  The first
-** argument may be NULL in which case SQLite will allocate the lookaside
-** buffer itself using [sqlite3_malloc()].  The second argument is the
-** size of each lookaside buffer slot and the third argument is the number of
+** ^The first argument (the third parameter to [sqlite3_db_config()] is a
+** pointer to a memory buffer to use for lookaside memory.
+** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
+** may be NULL in which case SQLite will allocate the
+** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
+** size of each lookaside buffer slot.  ^The third argument is the number of
 ** slots.  The size of the buffer in the first argument must be greater than
-** or equal to the product of the second and third arguments.</dd>
+** or equal to the product of the second and third arguments.  The buffer
+** must be aligned to an 8-byte boundary.  ^If the second argument to
+** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
+** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
+** configuration for a database connection can only be changed when that
+** connection is not currently using lookaside memory, or in other words
+** when the "current value" returned by
+** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
+** Any attempt to change the lookaside memory configuration when lookaside
+** memory is in use leaves the configuration unchanged and returns 
+** [SQLITE_BUSY].)^</dd>
+**
+** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
+** <dd> ^This option is used to enable or disable the enforcement of
+** [foreign key constraints].  There should be two additional arguments.
+** The first argument is an integer which is 0 to disable FK enforcement,
+** positive to enable FK enforcement or negative to leave FK enforcement
+** unchanged.  The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether FK enforcement is off or on
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the FK enforcement setting is not reported back. </dd>
+**
+** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
+** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
+** There should be two additional arguments.
+** The first argument is an integer which is 0 to disable triggers,
+** positive to enable triggers or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether triggers are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the trigger setting is not reported back. </dd>
 **
 ** </dl>
 */
-#define SQLITE_DBCONFIG_LOOKASIDE    1001  /* void* int int */
+#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
+#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
 
 
 /*
-** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700>
+** CAPI3REF: Enable Or Disable Extended Result Codes
 **
-** The sqlite3_extended_result_codes() routine enables or disables the
-** [extended result codes] feature of SQLite. The extended result
-** codes are disabled by default for historical compatibility considerations.
-**
-** INVARIANTS:
-**
-** {H12201} Each new [database connection] shall have the
-**          [extended result codes] feature disabled by default.
-**
-** {H12202} The [sqlite3_extended_result_codes(D,F)] interface shall enable
-**          [extended result codes] for the  [database connection] D
-**          if the F parameter is true, or disable them if F is false.
+** ^The sqlite3_extended_result_codes() routine enables or disables the
+** [extended result codes] feature of SQLite. ^The extended result
+** codes are disabled by default for historical compatibility.
 */
-int sqlite3_extended_result_codes(sqlite3*, int onoff);
+SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
 
 /*
-** CAPI3REF: Last Insert Rowid {H12220} <S10700>
+** CAPI3REF: Last Insert Rowid
 **
-** Each entry in an SQLite table has a unique 64-bit signed
-** integer key called the [ROWID | "rowid"]. The rowid is always available
+** ^Each entry in an SQLite table has a unique 64-bit signed
+** integer key called the [ROWID | "rowid"]. ^The rowid is always available
 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
-** names are not also used by explicitly declared columns. If
+** names are not also used by explicitly declared columns. ^If
 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
 ** is another alias for the rowid.
 **
-** This routine returns the [rowid] of the most recent
+** ^This routine returns the [rowid] of the most recent
 ** successful [INSERT] into the database from the [database connection]
-** in the first argument.  If no successful [INSERT]s
+** in the first argument.  ^As of SQLite version 3.7.7, this routines
+** records the last insert rowid of both ordinary tables and [virtual tables].
+** ^If no successful [INSERT]s
 ** have ever occurred on that database connection, zero is returned.
 **
-** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
-** row is returned by this routine as long as the trigger is running.
-** But once the trigger terminates, the value returned by this routine
-** reverts to the last value inserted before the trigger fired.
+** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
+** method, then this routine will return the [rowid] of the inserted
+** row as long as the trigger or virtual table method is running.
+** But once the trigger or virtual table method ends, the value returned 
+** by this routine reverts to what it was before the trigger or virtual
+** table method began.)^
 **
-** An [INSERT] that fails due to a constraint violation is not a
+** ^An [INSERT] that fails due to a constraint violation is not a
 ** successful [INSERT] and does not change the value returned by this
-** routine.  Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
+** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
 ** and INSERT OR ABORT make no changes to the return value of this
-** routine when their insertion fails.  When INSERT OR REPLACE
+** routine when their insertion fails.  ^(When INSERT OR REPLACE
 ** encounters a constraint violation, it does not fail.  The
 ** INSERT continues to completion after deleting rows that caused
 ** the constraint problem so INSERT OR REPLACE will always change
-** the return value of this interface.
+** the return value of this interface.)^
 **
-** For the purposes of this routine, an [INSERT] is considered to
+** ^For the purposes of this routine, an [INSERT] is considered to
 ** be successful even if it is subsequently rolled back.
 **
-** INVARIANTS:
+** This function is accessible to SQL statements via the
+** [last_insert_rowid() SQL function].
 **
-** {H12221} The [sqlite3_last_insert_rowid()] function shall return
-**          the [rowid]
-**          of the most recent successful [INSERT] performed on the same
-**          [database connection] and within the same or higher level
-**          trigger context, or zero if there have been no qualifying
-**          [INSERT] statements.
-**
-** {H12223} The [sqlite3_last_insert_rowid()] function shall return the
-**          same value when called from the same trigger context
-**          immediately before and after a [ROLLBACK].
-**
-** ASSUMPTIONS:
-**
-** {A12232} If a separate thread performs a new [INSERT] on the same
-**          database connection while the [sqlite3_last_insert_rowid()]
-**          function is running and thus changes the last insert [rowid],
-**          then the value returned by [sqlite3_last_insert_rowid()] is
-**          unpredictable and might not equal either the old or the new
-**          last insert [rowid].
+** If a separate thread performs a new [INSERT] on the same
+** database connection while the [sqlite3_last_insert_rowid()]
+** function is running and thus changes the last insert [rowid],
+** then the value returned by [sqlite3_last_insert_rowid()] is
+** unpredictable and might not equal either the old or the new
+** last insert [rowid].
 */
-sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
 
 /*
-** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600>
+** CAPI3REF: Count The Number Of Rows Modified
 **
-** This function returns the number of database rows that were changed
+** ^This function returns the number of database rows that were changed
 ** or inserted or deleted by the most recently completed SQL statement
 ** on the [database connection] specified by the first parameter.
-** Only changes that are directly specified by the [INSERT], [UPDATE],
+** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
 ** or [DELETE] statement are counted.  Auxiliary changes caused by
-** triggers are not counted. Use the [sqlite3_total_changes()] function
-** to find the total number of changes including changes caused by triggers.
+** triggers or [foreign key actions] are not counted.)^ Use the
+** [sqlite3_total_changes()] function to find the total number of changes
+** including changes caused by triggers and foreign key actions.
 **
-** A "row change" is a change to a single row of a single table
+** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
+** are not counted.  Only real table changes are counted.
+**
+** ^(A "row change" is a change to a single row of a single table
 ** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
-** are changed as side effects of REPLACE constraint resolution,
-** rollback, ABORT processing, DROP TABLE, or by any other
-** mechanisms do not count as direct row changes.
+** are changed as side effects of [REPLACE] constraint resolution,
+** rollback, ABORT processing, [DROP TABLE], or by any other
+** mechanisms do not count as direct row changes.)^
 **
 ** A "trigger context" is a scope of execution that begins and
-** ends with the script of a trigger.  Most SQL statements are
+** ends with the script of a [CREATE TRIGGER | trigger]. 
+** Most SQL statements are
 ** evaluated outside of any trigger.  This is the "top level"
 ** trigger context.  If a trigger fires from the top level, a
 ** new trigger context is entered for the duration of that one
 ** trigger.  Subtriggers create subcontexts for their duration.
 **
-** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
+** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
 ** not create a new trigger context.
 **
-** This function returns the number of direct row changes in the
+** ^This function returns the number of direct row changes in the
 ** most recent INSERT, UPDATE, or DELETE statement within the same
 ** trigger context.
 **
-** Thus, when called from the top level, this function returns the
+** ^Thus, when called from the top level, this function returns the
 ** number of changes in the most recent INSERT, UPDATE, or DELETE
-** that also occurred at the top level.  Within the body of a trigger,
+** that also occurred at the top level.  ^(Within the body of a trigger,
 ** the sqlite3_changes() interface can be called to find the number of
 ** changes in the most recently completed INSERT, UPDATE, or DELETE
 ** statement within the body of the same trigger.
 ** However, the number returned does not include changes
-** caused by subtriggers since those have their own context.
+** caused by subtriggers since those have their own context.)^
 **
-** SQLite implements the command "DELETE FROM table" without a WHERE clause
-** by dropping and recreating the table.  Doing so is much faster than going
-** through and deleting individual elements from the table.  Because of this
-** optimization, the deletions in "DELETE FROM table" are not row changes and
-** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
-** functions, regardless of the number of elements that were originally
-** in the table.  To get an accurate count of the number of rows deleted, use
-** "DELETE FROM table WHERE 1" instead.  Or recompile using the
-** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the
-** optimization on all queries.
+** See also the [sqlite3_total_changes()] interface, the
+** [count_changes pragma], and the [changes() SQL function].
 **
-** INVARIANTS:
-**
-** {H12241} The [sqlite3_changes()] function shall return the number of
-**          row changes caused by the most recent INSERT, UPDATE,
-**          or DELETE statement on the same database connection and
-**          within the same or higher trigger context, or zero if there have
-**          not been any qualifying row changes.
-**
-** {H12243} Statements of the form "DELETE FROM tablename" with no
-**          WHERE clause shall cause subsequent calls to
-**          [sqlite3_changes()] to return zero, regardless of the
-**          number of rows originally in the table.
-**
-** ASSUMPTIONS:
-**
-** {A12252} If a separate thread makes changes on the same database connection
-**          while [sqlite3_changes()] is running then the value returned
-**          is unpredictable and not meaningful.
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_changes()] is running then the value returned
+** is unpredictable and not meaningful.
 */
-int sqlite3_changes(sqlite3*);
+SQLITE_API int sqlite3_changes(sqlite3*);
 
 /*
-** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600>
+** CAPI3REF: Total Number Of Rows Modified
 **
-** This function returns the number of row changes caused by INSERT,
-** UPDATE or DELETE statements since the [database connection] was opened.
-** The count includes all changes from all trigger contexts.  However,
-** the count does not include changes used to implement REPLACE constraints,
-** do rollbacks or ABORT processing, or DROP table processing.
-** The changes are counted as soon as the statement that makes them is
-** completed (when the statement handle is passed to [sqlite3_reset()] or
-** [sqlite3_finalize()]).
+** ^This function returns the number of row changes caused by [INSERT],
+** [UPDATE] or [DELETE] statements since the [database connection] was opened.
+** ^(The count returned by sqlite3_total_changes() includes all changes
+** from all [CREATE TRIGGER | trigger] contexts and changes made by
+** [foreign key actions]. However,
+** the count does not include changes used to implement [REPLACE] constraints,
+** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The
+** count does not include rows of views that fire an [INSTEAD OF trigger],
+** though if the INSTEAD OF trigger makes changes of its own, those changes 
+** are counted.)^
+** ^The sqlite3_total_changes() function counts the changes as soon as
+** the statement that makes them is completed (when the statement handle
+** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
 **
-** SQLite implements the command "DELETE FROM table" without a WHERE clause
-** by dropping and recreating the table.  (This is much faster than going
-** through and deleting individual elements from the table.)  Because of this
-** optimization, the deletions in "DELETE FROM table" are not row changes and
-** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
-** functions, regardless of the number of elements that were originally
-** in the table.  To get an accurate count of the number of rows deleted, use
-** "DELETE FROM table WHERE 1" instead.   Or recompile using the
-** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the
-** optimization on all queries.
+** See also the [sqlite3_changes()] interface, the
+** [count_changes pragma], and the [total_changes() SQL function].
 **
-** See also the [sqlite3_changes()] interface.
-**
-** INVARIANTS:
-**
-** {H12261} The [sqlite3_total_changes()] returns the total number
-**          of row changes caused by INSERT, UPDATE, and/or DELETE
-**          statements on the same [database connection], in any
-**          trigger context, since the database connection was created.
-**
-** {H12263} Statements of the form "DELETE FROM tablename" with no
-**          WHERE clause shall not change the value returned
-**          by [sqlite3_total_changes()].
-**
-** ASSUMPTIONS:
-**
-** {A12264} If a separate thread makes changes on the same database connection
-**          while [sqlite3_total_changes()] is running then the value
-**          returned is unpredictable and not meaningful.
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_total_changes()] is running then the value
+** returned is unpredictable and not meaningful.
 */
-int sqlite3_total_changes(sqlite3*);
+SQLITE_API int sqlite3_total_changes(sqlite3*);
 
 /*
-** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500>
+** CAPI3REF: Interrupt A Long-Running Query
 **
-** This function causes any pending database operation to abort and
+** ^This function causes any pending database operation to abort and
 ** return at its earliest opportunity. This routine is typically
 ** called in response to a user action such as pressing "Cancel"
 ** or Ctrl-C where the user wants a long query operation to halt
 ** immediately.
 **
-** It is safe to call this routine from a thread different from the
+** ^It is safe to call this routine from a thread different from the
 ** thread that is currently running the database operation.  But it
 ** is not safe to call this routine with a [database connection] that
 ** is closed or might close before sqlite3_interrupt() returns.
 **
-** If an SQL operation is very nearly finished at the time when
+** ^If an SQL operation is very nearly finished at the time when
 ** sqlite3_interrupt() is called, then it might not have an opportunity
 ** to be interrupted and might continue to completion.
 **
-** An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
-** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
+** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
+** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
 ** that is inside an explicit transaction, then the entire transaction
 ** will be rolled back automatically.
 **
-** A call to sqlite3_interrupt() has no effect on SQL statements
-** that are started after sqlite3_interrupt() returns.
+** ^The sqlite3_interrupt(D) call is in effect until all currently running
+** SQL statements on [database connection] D complete.  ^Any new SQL statements
+** that are started after the sqlite3_interrupt() call and before the 
+** running statements reaches zero are interrupted as if they had been
+** running prior to the sqlite3_interrupt() call.  ^New SQL statements
+** that are started after the running statement count reaches zero are
+** not effected by the sqlite3_interrupt().
+** ^A call to sqlite3_interrupt(D) that occurs when there are no running
+** SQL statements is a no-op and has no effect on SQL statements
+** that are started after the sqlite3_interrupt() call returns.
 **
-** INVARIANTS:
-**
-** {H12271} The [sqlite3_interrupt()] interface will force all running
-**          SQL statements associated with the same database connection
-**          to halt after processing at most one additional row of data.
-**
-** {H12272} Any SQL statement that is interrupted by [sqlite3_interrupt()]
-**          will return [SQLITE_INTERRUPT].
-**
-** ASSUMPTIONS:
-**
-** {A12279} If the database connection closes while [sqlite3_interrupt()]
-**          is running then bad things will likely happen.
+** If the database connection closes while [sqlite3_interrupt()]
+** is running then bad things will likely happen.
 */
-void sqlite3_interrupt(sqlite3*);
+SQLITE_API void sqlite3_interrupt(sqlite3*);
 
 /*
-** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200>
+** CAPI3REF: Determine If An SQL Statement Is Complete
 **
-** These routines are useful for command-line input to determine if the
-** currently entered text seems to form complete a SQL statement or
+** These routines are useful during command-line input to determine if the
+** currently entered text seems to form a complete SQL statement or
 ** if additional input is needed before sending the text into
-** SQLite for parsing.  These routines return true if the input string
-** appears to be a complete SQL statement.  A statement is judged to be
-** complete if it ends with a semicolon token and is not a fragment of a
-** CREATE TRIGGER statement.  Semicolons that are embedded within
+** SQLite for parsing.  ^These routines return 1 if the input string
+** appears to be a complete SQL statement.  ^A statement is judged to be
+** complete if it ends with a semicolon token and is not a prefix of a
+** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
 ** string literals or quoted identifier names or comments are not
 ** independent tokens (they are part of the token in which they are
-** embedded) and thus do not count as a statement terminator.
+** embedded) and thus do not count as a statement terminator.  ^Whitespace
+** and comments that follow the final semicolon are ignored.
 **
-** These routines do not parse the SQL statements thus
+** ^These routines return 0 if the statement is incomplete.  ^If a
+** memory allocation fails, then SQLITE_NOMEM is returned.
+**
+** ^These routines do not parse the SQL statements thus
 ** will not detect syntactically incorrect SQL.
 **
-** INVARIANTS:
+** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 
+** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
+** automatically by sqlite3_complete16().  If that initialization fails,
+** then the return value from sqlite3_complete16() will be non-zero
+** regardless of whether or not the input SQL is complete.)^
 **
-** {H10511} A successful evaluation of [sqlite3_complete()] or
-**          [sqlite3_complete16()] functions shall
-**          return a numeric 1 if and only if the last non-whitespace
-**          token in their input is a semicolon that is not in between
-**          the BEGIN and END of a CREATE TRIGGER statement.
+** The input to [sqlite3_complete()] must be a zero-terminated
+** UTF-8 string.
 **
-** {H10512} If a memory allocation error occurs during an invocation
-**          of [sqlite3_complete()] or [sqlite3_complete16()] then the
-**          routine shall return [SQLITE_NOMEM].
-**
-** ASSUMPTIONS:
-**
-** {A10512} The input to [sqlite3_complete()] must be a zero-terminated
-**          UTF-8 string.
-**
-** {A10513} The input to [sqlite3_complete16()] must be a zero-terminated
-**          UTF-16 string in native byte order.
+** The input to [sqlite3_complete16()] must be a zero-terminated
+** UTF-16 string in native byte order.
 */
-int sqlite3_complete(const char *sql);
-int sqlite3_complete16(const void *sql);
+SQLITE_API int sqlite3_complete(const char *sql);
+SQLITE_API int sqlite3_complete16(const void *sql);
 
 /*
-** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400>
+** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
 **
-** This routine sets a callback function that might be invoked whenever
+** ^This routine sets a callback function that might be invoked whenever
 ** an attempt is made to open a database table that another thread
 ** or process has locked.
 **
-** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
-** is returned immediately upon encountering the lock. If the busy callback
-** is not NULL, then the callback will be invoked with two arguments.
+** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
+** is returned immediately upon encountering the lock.  ^If the busy callback
+** is not NULL, then the callback might be invoked with two arguments.
 **
-** The first argument to the handler is a copy of the void* pointer which
-** is the third argument to sqlite3_busy_handler().  The second argument to
-** the handler callback is the number of times that the busy handler has
-** been invoked for this locking event.  If the
+** ^The first argument to the busy handler is a copy of the void* pointer which
+** is the third argument to sqlite3_busy_handler().  ^The second argument to
+** the busy handler callback is the number of times that the busy handler has
+** been invoked for this locking event.  ^If the
 ** busy callback returns 0, then no additional attempts are made to
 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
-** If the callback returns non-zero, then another attempt
+** ^If the callback returns non-zero, then another attempt
 ** is made to open the database for reading and the cycle repeats.
 **
 ** The presence of a busy handler does not guarantee that it will be invoked
-** when there is lock contention. If SQLite determines that invoking the busy
+** when there is lock contention. ^If SQLite determines that invoking the busy
 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
 ** Consider a scenario where one process is holding a read lock that
@@ -1696,99 +1904,62 @@ int sqlite3_complete16(const void *sql);
 ** will induce the first process to release its read lock and allow
 ** the second process to proceed.
 **
-** The default busy callback is NULL.
+** ^The default busy callback is NULL.
 **
-** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
+** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
 ** when SQLite is in the middle of a large transaction where all the
 ** changes will not fit into the in-memory cache.  SQLite will
 ** already hold a RESERVED lock on the database file, but it needs
 ** to promote this lock to EXCLUSIVE so that it can spill cache
 ** pages into the database file without harm to concurrent
-** readers.  If it is unable to promote the lock, then the in-memory
+** readers.  ^If it is unable to promote the lock, then the in-memory
 ** cache will be left in an inconsistent state and so the error
 ** code is promoted from the relatively benign [SQLITE_BUSY] to
-** the more severe [SQLITE_IOERR_BLOCKED].  This error code promotion
+** the more severe [SQLITE_IOERR_BLOCKED].  ^This error code promotion
 ** forces an automatic rollback of the changes.  See the
 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
 ** this is important.
 **
-** There can only be a single busy handler defined for each
+** ^(There can only be a single busy handler defined for each
 ** [database connection].  Setting a new busy handler clears any
-** previously set handler.  Note that calling [sqlite3_busy_timeout()]
+** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
 ** will also set or clear the busy handler.
 **
 ** The busy callback should not take any actions which modify the
 ** database connection that invoked the busy handler.  Any such actions
 ** result in undefined behavior.
 ** 
-** INVARIANTS:
-**
-** {H12311} The [sqlite3_busy_handler(D,C,A)] function shall replace
-**          busy callback in the [database connection] D with a new
-**          a new busy handler C and application data pointer A.
-**
-** {H12312} Newly created [database connections] shall have a busy
-**          handler of NULL.
-**
-** {H12314} When two or more [database connections] share a
-**          [sqlite3_enable_shared_cache | common cache],
-**          the busy handler for the database connection currently using
-**          the cache shall be invoked when the cache encounters a lock.
-**
-** {H12316} If a busy handler callback returns zero, then the SQLite interface
-**          that provoked the locking event shall return [SQLITE_BUSY].
-**
-** {H12318} SQLite shall invokes the busy handler with two arguments which
-**          are a copy of the pointer supplied by the 3rd parameter to
-**          [sqlite3_busy_handler()] and a count of the number of prior
-**          invocations of the busy handler for the same locking event.
-**
-** ASSUMPTIONS:
-**
-** {A12319} A busy handler must not close the database connection
-**          or [prepared statement] that invoked the busy handler.
+** A busy handler must not close the database connection
+** or [prepared statement] that invoked the busy handler.
 */
-int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
+SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
 
 /*
-** CAPI3REF: Set A Busy Timeout {H12340} <S40410>
+** CAPI3REF: Set A Busy Timeout
 **
-** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
-** for a specified amount of time when a table is locked.  The handler
+** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
+** for a specified amount of time when a table is locked.  ^The handler
 ** will sleep multiple times until at least "ms" milliseconds of sleeping
-** have accumulated. {H12343} After "ms" milliseconds of sleeping,
+** have accumulated.  ^After at least "ms" milliseconds of sleeping,
 ** the handler returns 0 which causes [sqlite3_step()] to return
 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
 **
-** Calling this routine with an argument less than or equal to zero
+** ^Calling this routine with an argument less than or equal to zero
 ** turns off all busy handlers.
 **
-** There can only be a single busy handler for a particular
+** ^(There can only be a single busy handler for a particular
 ** [database connection] any any given moment.  If another busy handler
 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
-** this routine, that other busy handler is cleared.
-**
-** INVARIANTS:
-**
-** {H12341} The [sqlite3_busy_timeout()] function shall override any prior
-**          [sqlite3_busy_timeout()] or [sqlite3_busy_handler()] setting
-**          on the same [database connection].
-**
-** {H12343} If the 2nd parameter to [sqlite3_busy_timeout()] is less than
-**          or equal to zero, then the busy handler shall be cleared so that
-**          all subsequent locking events immediately return [SQLITE_BUSY].
-**
-** {H12344} If the 2nd parameter to [sqlite3_busy_timeout()] is a positive
-**          number N, then a busy handler shall be set that repeatedly calls
-**          the xSleep() method in the [sqlite3_vfs | VFS interface] until
-**          either the lock clears or until the cumulative sleep time
-**          reported back by xSleep() exceeds N milliseconds.
+** this routine, that other busy handler is cleared.)^
 */
-int sqlite3_busy_timeout(sqlite3*, int ms);
+SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
 
 /*
-** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000>
+** CAPI3REF: Convenience Routines For Running Queries
+**
+** This is a legacy interface that is preserved for backwards compatibility.
+** Use of this interface is not recommended.
 **
 ** Definition: A <b>result table</b> is memory data structure created by the
 ** [sqlite3_get_table()] interface.  A result table records the
@@ -1810,7 +1981,7 @@ int sqlite3_busy_timeout(sqlite3*, int ms);
 ** It is not safe to pass a result table directly to [sqlite3_free()].
 ** A result table should be deallocated using [sqlite3_free_table()].
 **
-** As an example of the result table format, suppose a query result
+** ^(As an example of the result table format, suppose a query result
 ** is as follows:
 **
 ** <blockquote><pre>
@@ -1834,15 +2005,15 @@ int sqlite3_busy_timeout(sqlite3*, int ms);
 **        azResult&#91;5] = "28";
 **        azResult&#91;6] = "Cindy";
 **        azResult&#91;7] = "21";
-** </pre></blockquote>
+** </pre></blockquote>)^
 **
-** The sqlite3_get_table() function evaluates one or more
+** ^The sqlite3_get_table() function evaluates one or more
 ** semicolon-separated SQL statements in the zero-terminated UTF-8
-** string of its 2nd parameter.  It returns a result table to the
+** string of its 2nd parameter and returns a result table to the
 ** pointer given in its 3rd parameter.
 **
-** After the calling function has finished using the result, it should
-** pass the pointer to the result table to sqlite3_free_table() in order to
+** After the application has finished with the result from sqlite3_get_table(),
+** it must pass the result table pointer to sqlite3_free_table() in order to
 ** release the memory that was malloced.  Because of the way the
 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
 ** function must not try to call [sqlite3_free()] directly.  Only
@@ -1853,42 +2024,10 @@ int sqlite3_busy_timeout(sqlite3*, int ms);
 ** to any internal data structures of SQLite.  It uses only the public
 ** interface defined here.  As a consequence, errors that occur in the
 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
-** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()].
-**
-** INVARIANTS:
-**
-** {H12371} If a [sqlite3_get_table()] fails a memory allocation, then
-**          it shall free the result table under construction, abort the
-**          query in process, skip any subsequent queries, set the
-**          *pazResult output pointer to NULL and return [SQLITE_NOMEM].
-**
-** {H12373} If the pnColumn parameter to [sqlite3_get_table()] is not NULL
-**          then a successful invocation of [sqlite3_get_table()] shall
-**          write the number of columns in the
-**          result set of the query into *pnColumn.
-**
-** {H12374} If the pnRow parameter to [sqlite3_get_table()] is not NULL
-**          then a successful invocation of [sqlite3_get_table()] shall
-**          writes the number of rows in the
-**          result set of the query into *pnRow.
-**
-** {H12376} A successful invocation of [sqlite3_get_table()] that computes
-**          N rows of result with C columns per row shall make *pazResult
-**          point to an array of pointers to (N+1)*C strings where the first
-**          C strings are column names as obtained from
-**          [sqlite3_column_name()] and the rest are column result values
-**          obtained from [sqlite3_column_text()].
-**
-** {H12379} The values in the pazResult array returned by [sqlite3_get_table()]
-**          shall remain valid until cleared by [sqlite3_free_table()].
-**
-** {H12382} When an error occurs during evaluation of [sqlite3_get_table()]
-**          the function shall set *pazResult to NULL, write an error message
-**          into memory obtained from [sqlite3_malloc()], make
-**          **pzErrmsg point to that error message, and return a
-**          appropriate [error code].
+** reflected in subsequent calls to [sqlite3_errcode()] or
+** [sqlite3_errmsg()].
 */
-int sqlite3_get_table(
+SQLITE_API int sqlite3_get_table(
   sqlite3 *db,          /* An open database */
   const char *zSql,     /* SQL to be evaluated */
   char ***pazResult,    /* Results of the query */
@@ -1896,48 +2035,50 @@ int sqlite3_get_table(
   int *pnColumn,        /* Number of result columns written here */
   char **pzErrmsg       /* Error msg written here */
 );
-void sqlite3_free_table(char **result);
+SQLITE_API void sqlite3_free_table(char **result);
 
 /*
-** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000>
+** CAPI3REF: Formatted String Printing Functions
 **
-** These routines are workalikes of the "printf()" family of functions
+** These routines are work-alikes of the "printf()" family of functions
 ** from the standard C library.
 **
-** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
+** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
 ** results into memory obtained from [sqlite3_malloc()].
 ** The strings returned by these two routines should be
-** released by [sqlite3_free()].  Both routines return a
+** released by [sqlite3_free()].  ^Both routines return a
 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
 ** memory to hold the resulting string.
 **
-** In sqlite3_snprintf() routine is similar to "snprintf()" from
+** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
 ** the standard C library.  The result is written into the
 ** buffer supplied as the second parameter whose size is given by
 ** the first parameter. Note that the order of the
-** first two parameters is reversed from snprintf().  This is an
+** first two parameters is reversed from snprintf().)^  This is an
 ** historical accident that cannot be fixed without breaking
-** backwards compatibility.  Note also that sqlite3_snprintf()
+** backwards compatibility.  ^(Note also that sqlite3_snprintf()
 ** returns a pointer to its buffer instead of the number of
-** characters actually written into the buffer.  We admit that
+** characters actually written into the buffer.)^  We admit that
 ** the number of characters written would be a more useful return
 ** value but we cannot change the implementation of sqlite3_snprintf()
 ** now without breaking compatibility.
 **
-** As long as the buffer size is greater than zero, sqlite3_snprintf()
-** guarantees that the buffer is always zero-terminated.  The first
+** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
+** guarantees that the buffer is always zero-terminated.  ^The first
 ** parameter "n" is the total size of the buffer, including space for
 ** the zero terminator.  So the longest string that can be completely
 ** written will be n-1 characters.
 **
+** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
+**
 ** These routines all implement some additional formatting
 ** options that are useful for constructing SQL statements.
 ** All of the usual printf() formatting options apply.  In addition, there
 ** is are "%q", "%Q", and "%z" options.
 **
-** The %q option works like %s in that it substitutes a null-terminated
+** ^(The %q option works like %s in that it substitutes a nul-terminated
 ** string from the argument list.  But %q also doubles every '\'' character.
-** %q is designed for use inside a string literal.  By doubling each '\''
+** %q is designed for use inside a string literal.)^  By doubling each '\''
 ** character it escapes that character and allows it to be inserted into
 ** the string.
 **
@@ -1972,10 +2113,10 @@ void sqlite3_free_table(char **result);
 ** This second example is an SQL syntax error.  As a general rule you should
 ** always use %q instead of %s when inserting text into a string literal.
 **
-** The %Q option works like %q except it also adds single quotes around
+** ^(The %Q option works like %q except it also adds single quotes around
 ** the outside of the total string.  Additionally, if the parameter in the
 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
-** single quotes) in place of the %Q option.  So, for example, one could say:
+** single quotes).)^  So, for example, one could say:
 **
 ** <blockquote><pre>
 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
@@ -1986,49 +2127,33 @@ void sqlite3_free_table(char **result);
 ** The code above will render a correct SQL statement in the zSQL
 ** variable even if the zText variable is a NULL pointer.
 **
-** The "%z" formatting option works exactly like "%s" with the
+** ^(The "%z" formatting option works like "%s" but with the
 ** addition that after the string has been read and copied into
-** the result, [sqlite3_free()] is called on the input string. {END}
-**
-** INVARIANTS:
-**
-** {H17403}  The [sqlite3_mprintf()] and [sqlite3_vmprintf()] interfaces
-**           return either pointers to zero-terminated UTF-8 strings held in
-**           memory obtained from [sqlite3_malloc()] or NULL pointers if
-**           a call to [sqlite3_malloc()] fails.
-**
-** {H17406}  The [sqlite3_snprintf()] interface writes a zero-terminated
-**           UTF-8 string into the buffer pointed to by the second parameter
-**           provided that the first parameter is greater than zero.
-**
-** {H17407}  The [sqlite3_snprintf()] interface does not write slots of
-**           its output buffer (the second parameter) outside the range
-**           of 0 through N-1 (where N is the first parameter)
-**           regardless of the length of the string
-**           requested by the format specification.
+** the result, [sqlite3_free()] is called on the input string.)^
 */
-char *sqlite3_mprintf(const char*,...);
-char *sqlite3_vmprintf(const char*, va_list);
-char *sqlite3_snprintf(int,char*,const char*, ...);
+SQLITE_API char *sqlite3_mprintf(const char*,...);
+SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
+SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
+SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
 
 /*
-** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000>
+** CAPI3REF: Memory Allocation Subsystem
 **
-** The SQLite core  uses these three routines for all of its own
+** The SQLite core uses these three routines for all of its own
 ** internal memory allocation needs. "Core" in the previous sentence
 ** does not include operating-system specific VFS implementation.  The
 ** Windows VFS uses native malloc() and free() for some operations.
 **
-** The sqlite3_malloc() routine returns a pointer to a block
+** ^The sqlite3_malloc() routine returns a pointer to a block
 ** of memory at least N bytes in length, where N is the parameter.
-** If sqlite3_malloc() is unable to obtain sufficient free
-** memory, it returns a NULL pointer.  If the parameter N to
+** ^If sqlite3_malloc() is unable to obtain sufficient free
+** memory, it returns a NULL pointer.  ^If the parameter N to
 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
 ** a NULL pointer.
 **
-** Calling sqlite3_free() with a pointer previously returned
+** ^Calling sqlite3_free() with a pointer previously returned
 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
-** that it might be reused.  The sqlite3_free() routine is
+** that it might be reused.  ^The sqlite3_free() routine is
 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
 ** to sqlite3_free() is harmless.  After being freed, memory
 ** should neither be read nor written.  Even reading previously freed
@@ -2037,137 +2162,82 @@ char *sqlite3_snprintf(int,char*,const char*, ...);
 ** might result if sqlite3_free() is called with a non-NULL pointer that
 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
 **
-** The sqlite3_realloc() interface attempts to resize a
+** ^(The sqlite3_realloc() interface attempts to resize a
 ** prior memory allocation to be at least N bytes, where N is the
 ** second parameter.  The memory allocation to be resized is the first
-** parameter.  If the first parameter to sqlite3_realloc()
+** parameter.)^ ^ If the first parameter to sqlite3_realloc()
 ** is a NULL pointer then its behavior is identical to calling
 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
-** If the second parameter to sqlite3_realloc() is zero or
+** ^If the second parameter to sqlite3_realloc() is zero or
 ** negative then the behavior is exactly the same as calling
 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
-** sqlite3_realloc() returns a pointer to a memory allocation
+** ^sqlite3_realloc() returns a pointer to a memory allocation
 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
-** If M is the size of the prior allocation, then min(N,M) bytes
+** ^If M is the size of the prior allocation, then min(N,M) bytes
 ** of the prior allocation are copied into the beginning of buffer returned
 ** by sqlite3_realloc() and the prior allocation is freed.
-** If sqlite3_realloc() returns NULL, then the prior allocation
+** ^If sqlite3_realloc() returns NULL, then the prior allocation
 ** is not freed.
 **
-** The memory returned by sqlite3_malloc() and sqlite3_realloc()
-** is always aligned to at least an 8 byte boundary. {END}
-**
-** The default implementation of the memory allocation subsystem uses
-** the malloc(), realloc() and free() provided by the standard C library.
-** {H17382} However, if SQLite is compiled with the
-** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i>
-** is an integer), then SQLite create a static array of at least
-** <i>NNN</i> bytes in size and uses that array for all of its dynamic
-** memory allocation needs. {END}  Additional memory allocator options
-** may be added in future releases.
+** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
+** is always aligned to at least an 8 byte boundary, or to a
+** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
+** option is used.
 **
 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
 ** implementation of these routines to be omitted.  That capability
 ** is no longer provided.  Only built-in memory allocators can be used.
 **
-** The Windows OS interface layer calls
+** Prior to SQLite version 3.7.10, the Windows OS interface layer called
 ** the system malloc() and free() directly when converting
 ** filenames between the UTF-8 encoding used by SQLite
 ** and whatever filename encoding is used by the particular Windows
-** installation.  Memory allocation errors are detected, but
-** they are reported back as [SQLITE_CANTOPEN] or
+** installation.  Memory allocation errors were detected, but
+** they were reported back as [SQLITE_CANTOPEN] or
 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
 **
-** INVARIANTS:
+** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
+** must be either NULL or else pointers obtained from a prior
+** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
+** not yet been released.
 **
-** {H17303}  The [sqlite3_malloc(N)] interface returns either a pointer to
-**           a newly checked-out block of at least N bytes of memory
-**           that is 8-byte aligned, or it returns NULL if it is unable
-**           to fulfill the request.
-**
-** {H17304}  The [sqlite3_malloc(N)] interface returns a NULL pointer if
-**           N is less than or equal to zero.
-**
-** {H17305}  The [sqlite3_free(P)] interface releases memory previously
-**           returned from [sqlite3_malloc()] or [sqlite3_realloc()],
-**           making it available for reuse.
-**
-** {H17306}  A call to [sqlite3_free(NULL)] is a harmless no-op.
-**
-** {H17310}  A call to [sqlite3_realloc(0,N)] is equivalent to a call
-**           to [sqlite3_malloc(N)].
-**
-** {H17312}  A call to [sqlite3_realloc(P,0)] is equivalent to a call
-**           to [sqlite3_free(P)].
-**
-** {H17315}  The SQLite core uses [sqlite3_malloc()], [sqlite3_realloc()],
-**           and [sqlite3_free()] for all of its memory allocation and
-**           deallocation needs.
-**
-** {H17318}  The [sqlite3_realloc(P,N)] interface returns either a pointer
-**           to a block of checked-out memory of at least N bytes in size
-**           that is 8-byte aligned, or a NULL pointer.
-**
-** {H17321}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
-**           copies the first K bytes of content from P into the newly
-**           allocated block, where K is the lesser of N and the size of
-**           the buffer P.
-**
-** {H17322}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
-**           releases the buffer P.
-**
-** {H17323}  When [sqlite3_realloc(P,N)] returns NULL, the buffer P is
-**           not modified or released.
-**
-** ASSUMPTIONS:
-**
-** {A17350}  The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
-**           must be either NULL or else pointers obtained from a prior
-**           invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
-**           not yet been released.
-**
-** {A17351}  The application must not read or write any part of
-**           a block of memory after it has been released using
-**           [sqlite3_free()] or [sqlite3_realloc()].
+** The application must not read or write any part of
+** a block of memory after it has been released using
+** [sqlite3_free()] or [sqlite3_realloc()].
 */
-void *sqlite3_malloc(int);
-void *sqlite3_realloc(void*, int);
-void sqlite3_free(void*);
+SQLITE_API void *sqlite3_malloc(int);
+SQLITE_API void *sqlite3_realloc(void*, int);
+SQLITE_API void sqlite3_free(void*);
 
 /*
-** CAPI3REF: Memory Allocator Statistics {H17370} <S30210>
+** CAPI3REF: Memory Allocator Statistics
 **
 ** SQLite provides these two interfaces for reporting on the status
 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
 ** routines, which form the built-in memory allocation subsystem.
 **
-** INVARIANTS:
+** ^The [sqlite3_memory_used()] routine returns the number of bytes
+** of memory currently outstanding (malloced but not freed).
+** ^The [sqlite3_memory_highwater()] routine returns the maximum
+** value of [sqlite3_memory_used()] since the high-water mark
+** was last reset.  ^The values returned by [sqlite3_memory_used()] and
+** [sqlite3_memory_highwater()] include any overhead
+** added by SQLite in its implementation of [sqlite3_malloc()],
+** but not overhead added by the any underlying system library
+** routines that [sqlite3_malloc()] may call.
 **
-** {H17371} The [sqlite3_memory_used()] routine returns the number of bytes
-**          of memory currently outstanding (malloced but not freed).
-**
-** {H17373} The [sqlite3_memory_highwater()] routine returns the maximum
-**          value of [sqlite3_memory_used()] since the high-water mark
-**          was last reset.
-**
-** {H17374} The values returned by [sqlite3_memory_used()] and
-**          [sqlite3_memory_highwater()] include any overhead
-**          added by SQLite in its implementation of [sqlite3_malloc()],
-**          but not overhead added by the any underlying system library
-**          routines that [sqlite3_malloc()] may call.
-**
-** {H17375} The memory high-water mark is reset to the current value of
-**          [sqlite3_memory_used()] if and only if the parameter to
-**          [sqlite3_memory_highwater()] is true.  The value returned
-**          by [sqlite3_memory_highwater(1)] is the high-water mark
-**          prior to the reset.
+** ^The memory high-water mark is reset to the current value of
+** [sqlite3_memory_used()] if and only if the parameter to
+** [sqlite3_memory_highwater()] is true.  ^The value returned
+** by [sqlite3_memory_highwater(1)] is the high-water mark
+** prior to the reset.
 */
-sqlite3_int64 sqlite3_memory_used(void);
-sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
 
 /*
-** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000>
+** CAPI3REF: Pseudo-Random Number Generator
 **
 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
 ** select random [ROWID | ROWIDs] when inserting new records into a table that
@@ -2175,59 +2245,59 @@ sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
 ** the build-in random() and randomblob() SQL functions.  This interface allows
 ** applications to access the same PRNG for other purposes.
 **
-** A call to this routine stores N bytes of randomness into buffer P.
+** ^A call to this routine stores N bytes of randomness into buffer P.
 **
-** The first time this routine is invoked (either internally or by
+** ^The first time this routine is invoked (either internally or by
 ** the application) the PRNG is seeded using randomness obtained
 ** from the xRandomness method of the default [sqlite3_vfs] object.
-** On all subsequent invocations, the pseudo-randomness is generated
+** ^On all subsequent invocations, the pseudo-randomness is generated
 ** internally and without recourse to the [sqlite3_vfs] xRandomness
 ** method.
-**
-** INVARIANTS:
-**
-** {H17392} The [sqlite3_randomness(N,P)] interface writes N bytes of
-**          high-quality pseudo-randomness into buffer P.
 */
-void sqlite3_randomness(int N, void *P);
+SQLITE_API void sqlite3_randomness(int N, void *P);
 
 /*
-** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100>
+** CAPI3REF: Compile-Time Authorization Callbacks
 **
-** This routine registers a authorizer callback with a particular
+** ^This routine registers an authorizer callback with a particular
 ** [database connection], supplied in the first argument.
-** The authorizer callback is invoked as SQL statements are being compiled
+** ^The authorizer callback is invoked as SQL statements are being compiled
 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
-** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  At various
+** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
 ** points during the compilation process, as logic is being created
 ** to perform various actions, the authorizer callback is invoked to
-** see if those actions are allowed.  The authorizer callback should
+** see if those actions are allowed.  ^The authorizer callback should
 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
 ** specific action but allow the SQL statement to continue to be
 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
-** rejected with an error.  If the authorizer callback returns
+** rejected with an error.  ^If the authorizer callback returns
 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
 ** the authorizer will fail with an error message.
 **
 ** When the callback returns [SQLITE_OK], that means the operation
-** requested is ok.  When the callback returns [SQLITE_DENY], the
+** requested is ok.  ^When the callback returns [SQLITE_DENY], the
 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
 ** authorizer will fail with an error message explaining that
-** access is denied.  If the authorizer code is [SQLITE_READ]
+** access is denied. 
+**
+** ^The first parameter to the authorizer callback is a copy of the third
+** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
+** to the callback is an integer [SQLITE_COPY | action code] that specifies
+** the particular action to be authorized. ^The third through sixth parameters
+** to the callback are zero-terminated strings that contain additional
+** details about the action to be authorized.
+**
+** ^If the action code is [SQLITE_READ]
 ** and the callback returns [SQLITE_IGNORE] then the
 ** [prepared statement] statement is constructed to substitute
 ** a NULL value in place of the table column that would have
 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
 ** return can be used to deny an untrusted user access to individual
 ** columns of a table.
-**
-** The first parameter to the authorizer callback is a copy of the third
-** parameter to the sqlite3_set_authorizer() interface. The second parameter
-** to the callback is an integer [SQLITE_COPY | action code] that specifies
-** the particular action to be authorized. The third through sixth parameters
-** to the callback are zero-terminated strings that contain additional
-** details about the action to be authorized.
+** ^If the action code is [SQLITE_DELETE] and the callback returns
+** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
+** [truncate optimization] is disabled and all rows are deleted individually.
 **
 ** An authorizer is used when [sqlite3_prepare | preparing]
 ** SQL statements from an untrusted source, to ensure that the SQL statements
@@ -2245,9 +2315,9 @@ void sqlite3_randomness(int N, void *P);
 ** and limiting database size using the [max_page_count] [PRAGMA]
 ** in addition to using an authorizer.
 **
-** Only a single authorizer can be in place on a database connection
+** ^(Only a single authorizer can be in place on a database connection
 ** at a time.  Each call to sqlite3_set_authorizer overrides the
-** previous call.  Disable the authorizer by installing a NULL callback.
+** previous call.)^  ^Disable the authorizer by installing a NULL callback.
 ** The authorizer is disabled by default.
 **
 ** The authorizer callback must not do anything that will modify
@@ -2255,87 +2325,40 @@ void sqlite3_randomness(int N, void *P);
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
-** When [sqlite3_prepare_v2()] is used to prepare a statement, the
-** statement might be reprepared during [sqlite3_step()] due to a 
+** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
+** statement might be re-prepared during [sqlite3_step()] due to a 
 ** schema change.  Hence, the application should ensure that the
 ** correct authorizer callback remains in place during the [sqlite3_step()].
 **
-** Note that the authorizer callback is invoked only during
+** ^Note that the authorizer callback is invoked only during
 ** [sqlite3_prepare()] or its variants.  Authorization is not
-** performed during statement evaluation in [sqlite3_step()].
-**
-** INVARIANTS:
-**
-** {H12501} The [sqlite3_set_authorizer(D,...)] interface registers a
-**          authorizer callback with database connection D.
-**
-** {H12502} The authorizer callback is invoked as SQL statements are
-**          being parseed and compiled.
-**
-** {H12503} If the authorizer callback returns any value other than
-**          [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY], then
-**          the application interface call that caused
-**          the authorizer callback to run shall fail with an
-**          [SQLITE_ERROR] error code and an appropriate error message.
-**
-** {H12504} When the authorizer callback returns [SQLITE_OK], the operation
-**          described is processed normally.
-**
-** {H12505} When the authorizer callback returns [SQLITE_DENY], the
-**          application interface call that caused the
-**          authorizer callback to run shall fail
-**          with an [SQLITE_ERROR] error code and an error message
-**          explaining that access is denied.
-**
-** {H12506} If the authorizer code (the 2nd parameter to the authorizer
-**          callback) is [SQLITE_READ] and the authorizer callback returns
-**          [SQLITE_IGNORE], then the prepared statement is constructed to
-**          insert a NULL value in place of the table column that would have
-**          been read if [SQLITE_OK] had been returned.
-**
-** {H12507} If the authorizer code (the 2nd parameter to the authorizer
-**          callback) is anything other than [SQLITE_READ], then
-**          a return of [SQLITE_IGNORE] has the same effect as [SQLITE_DENY].
-**
-** {H12510} The first parameter to the authorizer callback is a copy of
-**          the third parameter to the [sqlite3_set_authorizer()] interface.
-**
-** {H12511} The second parameter to the callback is an integer
-**          [SQLITE_COPY | action code] that specifies the particular action
-**          to be authorized.
-**
-** {H12512} The third through sixth parameters to the callback are
-**          zero-terminated strings that contain
-**          additional details about the action to be authorized.
-**
-** {H12520} Each call to [sqlite3_set_authorizer()] overrides
-**          any previously installed authorizer.
-**
-** {H12521} A NULL authorizer means that no authorization
-**          callback is invoked.
-**
-** {H12522} The default authorizer is NULL.
+** performed during statement evaluation in [sqlite3_step()], unless
+** as stated in the previous paragraph, sqlite3_step() invokes
+** sqlite3_prepare_v2() to reprepare a statement after a schema change.
 */
-int sqlite3_set_authorizer(
+SQLITE_API int sqlite3_set_authorizer(
   sqlite3*,
   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
   void *pUserData
 );
 
 /*
-** CAPI3REF: Authorizer Return Codes {H12590} <H12500>
+** CAPI3REF: Authorizer Return Codes
 **
 ** The [sqlite3_set_authorizer | authorizer callback function] must
 ** return either [SQLITE_OK] or one of these two constants in order
 ** to signal SQLite whether or not the action is permitted.  See the
 ** [sqlite3_set_authorizer | authorizer documentation] for additional
 ** information.
+**
+** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
+** from the [sqlite3_vtab_on_conflict()] interface.
 */
 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
 
 /*
-** CAPI3REF: Authorizer Action Codes {H12550} <H12500>
+** CAPI3REF: Authorizer Action Codes
 **
 ** The [sqlite3_set_authorizer()] interface registers a callback function
 ** that is invoked to authorize certain SQL statement actions.  The
@@ -2346,34 +2369,12 @@ int sqlite3_set_authorizer(
 ** These action code values signify what kind of operation is to be
 ** authorized.  The 3rd and 4th parameters to the authorization
 ** callback function will be parameters or NULL depending on which of these
-** codes is used as the second parameter.  The 5th parameter to the
+** codes is used as the second parameter.  ^(The 5th parameter to the
 ** authorizer callback is the name of the database ("main", "temp",
-** etc.) if applicable.  The 6th parameter to the authorizer callback
+** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
 ** is the name of the inner-most trigger or view that is responsible for
 ** the access attempt or NULL if this access attempt is directly from
 ** top-level SQL code.
-**
-** INVARIANTS:
-**
-** {H12551} The second parameter to an
-**          [sqlite3_set_authorizer | authorizer callback] shall be an integer
-**          [SQLITE_COPY | authorizer code] that specifies what action
-**          is being authorized.
-**
-** {H12552} The 3rd and 4th parameters to the
-**          [sqlite3_set_authorizer | authorization callback]
-**          shall be parameters or NULL depending on which
-**          [SQLITE_COPY | authorizer code] is used as the second parameter.
-**
-** {H12553} The 5th parameter to the
-**          [sqlite3_set_authorizer | authorizer callback] shall be the name
-**          of the database (example: "main", "temp", etc.) if applicable.
-**
-** {H12554} The 6th parameter to the
-**          [sqlite3_set_authorizer | authorizer callback] shall be the name
-**          of the inner-most trigger or view that is responsible for
-**          the access attempt or NULL if this access attempt is directly from
-**          top-level SQL code.
 */
 /******************************************* 3rd ************ 4th ***********/
 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
@@ -2411,132 +2412,83 @@ int sqlite3_set_authorizer(
 #define SQLITE_COPY                  0   /* No longer used */
 
 /*
-** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400>
-** EXPERIMENTAL
+** CAPI3REF: Tracing And Profiling Functions
 **
 ** These routines register callback functions that can be used for
 ** tracing and profiling the execution of SQL statements.
 **
-** The callback function registered by sqlite3_trace() is invoked at
+** ^The callback function registered by sqlite3_trace() is invoked at
 ** various times when an SQL statement is being run by [sqlite3_step()].
-** The callback returns a UTF-8 rendering of the SQL statement text
-** as the statement first begins executing.  Additional callbacks occur
+** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
+** SQL statement text as the statement first begins executing.
+** ^(Additional sqlite3_trace() callbacks might occur
 ** as each triggered subprogram is entered.  The callbacks for triggers
-** contain a UTF-8 SQL comment that identifies the trigger.
+** contain a UTF-8 SQL comment that identifies the trigger.)^
 **
-** The callback function registered by sqlite3_profile() is invoked
-** as each SQL statement finishes.  The profile callback contains
+** ^The callback function registered by sqlite3_profile() is invoked
+** as each SQL statement finishes.  ^The profile callback contains
 ** the original statement text and an estimate of wall-clock time
-** of how long that statement took to run.
-**
-** INVARIANTS:
-**
-** {H12281} The callback function registered by [sqlite3_trace()] 
-**          shall be invoked
-**          whenever an SQL statement first begins to execute and
-**          whenever a trigger subprogram first begins to run.
-**
-** {H12282} Each call to [sqlite3_trace()] shall override the previously
-**          registered trace callback.
-**
-** {H12283} A NULL trace callback shall disable tracing.
-**
-** {H12284} The first argument to the trace callback shall be a copy of
-**          the pointer which was the 3rd argument to [sqlite3_trace()].
-**
-** {H12285} The second argument to the trace callback is a
-**          zero-terminated UTF-8 string containing the original text
-**          of the SQL statement as it was passed into [sqlite3_prepare_v2()]
-**          or the equivalent, or an SQL comment indicating the beginning
-**          of a trigger subprogram.
-**
-** {H12287} The callback function registered by [sqlite3_profile()] is invoked
-**          as each SQL statement finishes.
-**
-** {H12288} The first parameter to the profile callback is a copy of
-**          the 3rd parameter to [sqlite3_profile()].
-**
-** {H12289} The second parameter to the profile callback is a
-**          zero-terminated UTF-8 string that contains the complete text of
-**          the SQL statement as it was processed by [sqlite3_prepare_v2()]
-**          or the equivalent.
-**
-** {H12290} The third parameter to the profile callback is an estimate
-**          of the number of nanoseconds of wall-clock time required to
-**          run the SQL statement from start to finish.
+** of how long that statement took to run.  ^The profile callback
+** time is in units of nanoseconds, however the current implementation
+** is only capable of millisecond resolution so the six least significant
+** digits in the time are meaningless.  Future versions of SQLite
+** might provide greater resolution on the profiler callback.  The
+** sqlite3_profile() function is considered experimental and is
+** subject to change in future versions of SQLite.
 */
-SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
-SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
+SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
+SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
 
 /*
-** CAPI3REF: Query Progress Callbacks {H12910} <S60400>
+** CAPI3REF: Query Progress Callbacks
 **
-** This routine configures a callback function - the
-** progress callback - that is invoked periodically during long
-** running calls to [sqlite3_exec()], [sqlite3_step()] and
-** [sqlite3_get_table()].  An example use for this
+** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
+** function X to be invoked periodically during long running calls to
+** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
+** database connection D.  An example use for this
 ** interface is to keep a GUI updated during a large query.
 **
-** If the progress callback returns non-zero, the operation is
+** ^The parameter P is passed through as the only parameter to the 
+** callback function X.  ^The parameter N is the number of 
+** [virtual machine instructions] that are evaluated between successive
+** invocations of the callback X.
+**
+** ^Only a single progress handler may be defined at one time per
+** [database connection]; setting a new progress handler cancels the
+** old one.  ^Setting parameter X to NULL disables the progress handler.
+** ^The progress handler is also disabled by setting N to a value less
+** than 1.
+**
+** ^If the progress callback returns non-zero, the operation is
 ** interrupted.  This feature can be used to implement a
 ** "Cancel" button on a GUI progress dialog box.
 **
-** The progress handler must not do anything that will modify
+** The progress handler callback must not do anything that will modify
 ** the database connection that invoked the progress handler.
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
-** INVARIANTS:
-**
-** {H12911} The callback function registered by sqlite3_progress_handler()
-**          is invoked periodically during long running calls to
-**          [sqlite3_step()].
-**
-** {H12912} The progress callback is invoked once for every N virtual
-**          machine opcodes, where N is the second argument to
-**          the [sqlite3_progress_handler()] call that registered
-**          the callback.  If N is less than 1, sqlite3_progress_handler()
-**          acts as if a NULL progress handler had been specified.
-**
-** {H12913} The progress callback itself is identified by the third
-**          argument to sqlite3_progress_handler().
-**
-** {H12914} The fourth argument to sqlite3_progress_handler() is a
-**          void pointer passed to the progress callback
-**          function each time it is invoked.
-**
-** {H12915} If a call to [sqlite3_step()] results in fewer than N opcodes
-**          being executed, then the progress callback is never invoked.
-**
-** {H12916} Every call to [sqlite3_progress_handler()]
-**          overwrites any previously registered progress handler.
-**
-** {H12917} If the progress handler callback is NULL then no progress
-**          handler is invoked.
-**
-** {H12918} If the progress callback returns a result other than 0, then
-**          the behavior is a if [sqlite3_interrupt()] had been called.
-**          <S30500>
 */
-void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
+SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 
 /*
-** CAPI3REF: Opening A New Database Connection {H12700} <S40200>
+** CAPI3REF: Opening A New Database Connection
 **
-** These routines open an SQLite database file whose name is given by the
-** filename argument. The filename argument is interpreted as UTF-8 for
+** ^These routines open an SQLite database file as specified by the 
+** filename argument. ^The filename argument is interpreted as UTF-8 for
 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
-** order for sqlite3_open16(). A [database connection] handle is usually
+** order for sqlite3_open16(). ^(A [database connection] handle is usually
 ** returned in *ppDb, even if an error occurs.  The only exception is that
 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
-** object. If the database is opened (and/or created) successfully, then
-** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.  The
+** object.)^ ^(If the database is opened (and/or created) successfully, then
+** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
-** an English language description of the error.
+** an English language description of the error following a failure of any
+** of the sqlite3_open() routines.
 **
-** The default encoding for the database will be UTF-8 if
+** ^The default encoding for the database will be UTF-8 if
 ** sqlite3_open() or sqlite3_open_v2() is called and
 ** UTF-16 in the native byte order if sqlite3_open16() is used.
 **
@@ -2546,54 +2498,169 @@ void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 **
 ** The sqlite3_open_v2() interface works like sqlite3_open()
 ** except that it accepts two additional parameters for additional control
-** over the new database connection.  The flags parameter can take one of
+** over the new database connection.  ^(The flags parameter to
+** sqlite3_open_v2() can take one of
 ** the following three values, optionally combined with the 
-** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags:
+** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
+** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
 **
 ** <dl>
-** <dt>[SQLITE_OPEN_READONLY]</dt>
+** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
 ** <dd>The database is opened in read-only mode.  If the database does not
-** already exist, an error is returned.</dd>
+** already exist, an error is returned.</dd>)^
 **
-** <dt>[SQLITE_OPEN_READWRITE]</dt>
+** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
 ** <dd>The database is opened for reading and writing if possible, or reading
 ** only if the file is write protected by the operating system.  In either
-** case the database must already exist, otherwise an error is returned.</dd>
+** case the database must already exist, otherwise an error is returned.</dd>)^
 **
-** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
-** <dd>The database is opened for reading and writing, and is creates it if
+** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
+** <dd>The database is opened for reading and writing, and is created if
 ** it does not already exist. This is the behavior that is always used for
-** sqlite3_open() and sqlite3_open16().</dd>
+** sqlite3_open() and sqlite3_open16().</dd>)^
 ** </dl>
 **
 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
-** combinations shown above or one of the combinations shown above combined
-** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags,
+** combinations shown above optionally combined with other
+** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
 ** then the behavior is undefined.
 **
-** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
+** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
 ** opens in the multi-thread [threading mode] as long as the single-thread
-** mode has not been set at compile-time or start-time.  If the
+** mode has not been set at compile-time or start-time.  ^If the
 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
 ** in the serialized [threading mode] unless single-thread was
 ** previously selected at compile-time or start-time.
+** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
+** eligible to use [shared cache mode], regardless of whether or not shared
+** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
+** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
+** participate in [shared cache mode] even if it is enabled.
 **
-** If the filename is ":memory:", then a private, temporary in-memory database
-** is created for the connection.  This in-memory database will vanish when
+** ^The fourth parameter to sqlite3_open_v2() is the name of the
+** [sqlite3_vfs] object that defines the operating system interface that
+** the new database connection should use.  ^If the fourth parameter is
+** a NULL pointer then the default [sqlite3_vfs] object is used.
+**
+** ^If the filename is ":memory:", then a private, temporary in-memory database
+** is created for the connection.  ^This in-memory database will vanish when
 ** the database connection is closed.  Future versions of SQLite might
 ** make use of additional special filenames that begin with the ":" character.
 ** It is recommended that when a database filename actually does begin with
 ** a ":" character you should prefix the filename with a pathname such as
 ** "./" to avoid ambiguity.
 **
-** If the filename is an empty string, then a private, temporary
-** on-disk database will be created.  This private database will be
+** ^If the filename is an empty string, then a private, temporary
+** on-disk database will be created.  ^This private database will be
 ** automatically deleted as soon as the database connection is closed.
 **
-** The fourth parameter to sqlite3_open_v2() is the name of the
-** [sqlite3_vfs] object that defines the operating system interface that
-** the new database connection should use.  If the fourth parameter is
-** a NULL pointer then the default [sqlite3_vfs] object is used.
+** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
+**
+** ^If [URI filename] interpretation is enabled, and the filename argument
+** begins with "file:", then the filename is interpreted as a URI. ^URI
+** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
+** set in the fourth argument to sqlite3_open_v2(), or if it has
+** been enabled globally using the [SQLITE_CONFIG_URI] option with the
+** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
+** As of SQLite version 3.7.7, URI filename interpretation is turned off
+** by default, but future releases of SQLite might enable URI filename
+** interpretation by default.  See "[URI filenames]" for additional
+** information.
+**
+** URI filenames are parsed according to RFC 3986. ^If the URI contains an
+** authority, then it must be either an empty string or the string 
+** "localhost". ^If the authority is not an empty string or "localhost", an 
+** error is returned to the caller. ^The fragment component of a URI, if 
+** present, is ignored.
+**
+** ^SQLite uses the path component of the URI as the name of the disk file
+** which contains the database. ^If the path begins with a '/' character, 
+** then it is interpreted as an absolute path. ^If the path does not begin 
+** with a '/' (meaning that the authority section is omitted from the URI)
+** then the path is interpreted as a relative path. 
+** ^On windows, the first component of an absolute path 
+** is a drive specification (e.g. "C:").
+**
+** [[core URI query parameters]]
+** The query component of a URI may contain parameters that are interpreted
+** either by SQLite itself, or by a [VFS | custom VFS implementation].
+** SQLite interprets the following three query parameters:
+**
+** <ul>
+**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
+**     a VFS object that provides the operating system interface that should
+**     be used to access the database file on disk. ^If this option is set to
+**     an empty string the default VFS object is used. ^Specifying an unknown
+**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
+**     present, then the VFS specified by the option takes precedence over
+**     the value passed as the fourth parameter to sqlite3_open_v2().
+**
+**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
+**     "rwc", or "memory". Attempting to set it to any other value is
+**     an error)^. 
+**     ^If "ro" is specified, then the database is opened for read-only 
+**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 
+**     third argument to sqlite3_prepare_v2(). ^If the mode option is set to 
+**     "rw", then the database is opened for read-write (but not create) 
+**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 
+**     been set. ^Value "rwc" is equivalent to setting both 
+**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
+**     set to "memory" then a pure [in-memory database] that never reads
+**     or writes from disk is used. ^It is an error to specify a value for
+**     the mode parameter that is less restrictive than that specified by
+**     the flags passed in the third parameter to sqlite3_open_v2().
+**
+**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
+**     "private". ^Setting it to "shared" is equivalent to setting the
+**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
+**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is 
+**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
+**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
+**     a URI filename, its value overrides any behaviour requested by setting
+**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
+** </ul>
+**
+** ^Specifying an unknown parameter in the query component of a URI is not an
+** error.  Future versions of SQLite might understand additional query
+** parameters.  See "[query parameters with special meaning to SQLite]" for
+** additional information.
+**
+** [[URI filename examples]] <h3>URI filename examples</h3>
+**
+** <table border="1" align=center cellpadding=5>
+** <tr><th> URI filenames <th> Results
+** <tr><td> file:data.db <td> 
+**          Open the file "data.db" in the current directory.
+** <tr><td> file:/home/fred/data.db<br>
+**          file:///home/fred/data.db <br> 
+**          file://localhost/home/fred/data.db <br> <td> 
+**          Open the database file "/home/fred/data.db".
+** <tr><td> file://darkstar/home/fred/data.db <td> 
+**          An error. "darkstar" is not a recognized authority.
+** <tr><td style="white-space:nowrap"> 
+**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
+**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
+**          C:. Note that the %20 escaping in this example is not strictly 
+**          necessary - space characters can be used literally
+**          in URI filenames.
+** <tr><td> file:data.db?mode=ro&cache=private <td> 
+**          Open file "data.db" in the current directory for read-only access.
+**          Regardless of whether or not shared-cache mode is enabled by
+**          default, use a private cache.
+** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
+**          Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
+** <tr><td> file:data.db?mode=readonly <td> 
+**          An error. "readonly" is not a valid option for the "mode" parameter.
+** </table>
+**
+** ^URI hexadecimal escape sequences (%HH) are supported within the path and
+** query components of a URI. A hexadecimal escape sequence consists of a
+** percent sign - "%" - followed by exactly two hexadecimal digits 
+** specifying an octet value. ^Before the path or query components of a
+** URI filename are interpreted, they are encoded using UTF-8 and all 
+** hexadecimal escape sequences replaced by a single byte containing the
+** corresponding octet. If this process generates an invalid UTF-8 encoding,
+** the results are undefined.
 **
 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
@@ -2601,82 +2668,21 @@ void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 ** characters must be converted to UTF-8 prior to passing them into
 ** sqlite3_open() or sqlite3_open_v2().
 **
-** INVARIANTS:
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
+** features that require the use of temporary files may fail.
 **
-** {H12701} The [sqlite3_open()], [sqlite3_open16()], and
-**          [sqlite3_open_v2()] interfaces create a new
-**          [database connection] associated with
-**          the database file given in their first parameter.
-**
-** {H12702} The filename argument is interpreted as UTF-8
-**          for [sqlite3_open()] and [sqlite3_open_v2()] and as UTF-16
-**          in the native byte order for [sqlite3_open16()].
-**
-** {H12703} A successful invocation of [sqlite3_open()], [sqlite3_open16()],
-**          or [sqlite3_open_v2()] writes a pointer to a new
-**          [database connection] into *ppDb.
-**
-** {H12704} The [sqlite3_open()], [sqlite3_open16()], and
-**          [sqlite3_open_v2()] interfaces return [SQLITE_OK] upon success,
-**          or an appropriate [error code] on failure.
-**
-** {H12706} The default text encoding for a new database created using
-**          [sqlite3_open()] or [sqlite3_open_v2()] will be UTF-8.
-**
-** {H12707} The default text encoding for a new database created using
-**          [sqlite3_open16()] will be UTF-16.
-**
-** {H12709} The [sqlite3_open(F,D)] interface is equivalent to
-**          [sqlite3_open_v2(F,D,G,0)] where the G parameter is
-**          [SQLITE_OPEN_READWRITE]|[SQLITE_OPEN_CREATE].
-**
-** {H12711} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
-**          bit value [SQLITE_OPEN_READONLY] then the database is opened
-**          for reading only.
-**
-** {H12712} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
-**          bit value [SQLITE_OPEN_READWRITE] then the database is opened
-**          reading and writing if possible, or for reading only if the
-**          file is write protected by the operating system.
-**
-** {H12713} If the G parameter to [sqlite3_open_v2(F,D,G,V)] omits the
-**          bit value [SQLITE_OPEN_CREATE] and the database does not
-**          previously exist, an error is returned.
-**
-** {H12714} If the G parameter to [sqlite3_open_v2(F,D,G,V)] contains the
-**          bit value [SQLITE_OPEN_CREATE] and the database does not
-**          previously exist, then an attempt is made to create and
-**          initialize the database.
-**
-** {H12717} If the filename argument to [sqlite3_open()], [sqlite3_open16()],
-**          or [sqlite3_open_v2()] is ":memory:", then an private,
-**          ephemeral, in-memory database is created for the connection.
-**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
-**          in sqlite3_open_v2()?</todo>
-**
-** {H12719} If the filename is NULL or an empty string, then a private,
-**          ephemeral on-disk database will be created.
-**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
-**          in sqlite3_open_v2()?</todo>
-**
-** {H12721} The [database connection] created by [sqlite3_open_v2(F,D,G,V)]
-**          will use the [sqlite3_vfs] object identified by the V parameter,
-**          or the default [sqlite3_vfs] object if V is a NULL pointer.
-**
-** {H12723} Two [database connections] will share a common cache if both were
-**          opened with the same VFS while [shared cache mode] was enabled and
-**          if both filenames compare equal using memcmp() after having been
-**          processed by the [sqlite3_vfs | xFullPathname] method of the VFS.
+** See also: [sqlite3_temp_directory]
 */
-int sqlite3_open(
+SQLITE_API int sqlite3_open(
   const char *filename,   /* Database filename (UTF-8) */
   sqlite3 **ppDb          /* OUT: SQLite db handle */
 );
-int sqlite3_open16(
+SQLITE_API int sqlite3_open16(
   const void *filename,   /* Database filename (UTF-16) */
   sqlite3 **ppDb          /* OUT: SQLite db handle */
 );
-int sqlite3_open_v2(
+SQLITE_API int sqlite3_open_v2(
   const char *filename,   /* Database filename (UTF-8) */
   sqlite3 **ppDb,         /* OUT: SQLite db handle */
   int flags,              /* Flags */
@@ -2684,23 +2690,67 @@ int sqlite3_open_v2(
 );
 
 /*
-** CAPI3REF: Error Codes And Messages {H12800} <S60200>
+** CAPI3REF: Obtain Values For URI Parameters
 **
-** The sqlite3_errcode() interface returns the numeric [result code] or
+** These are utility routines, useful to VFS implementations, that check
+** to see if a database file was a URI that contained a specific query 
+** parameter, and if so obtains the value of that query parameter.
+**
+** If F is the database filename pointer passed into the xOpen() method of 
+** a VFS implementation when the flags parameter to xOpen() has one or 
+** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
+** P is the name of the query parameter, then
+** sqlite3_uri_parameter(F,P) returns the value of the P
+** parameter if it exists or a NULL pointer if P does not appear as a 
+** query parameter on F.  If P is a query parameter of F
+** has no explicit value, then sqlite3_uri_parameter(F,P) returns
+** a pointer to an empty string.
+**
+** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
+** parameter and returns true (1) or false (0) according to the value
+** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
+** value of query parameter P is one of "yes", "true", or "on" in any
+** case or if the value begins with a non-zero number.  The 
+** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
+** query parameter P is one of "no", "false", or "off" in any case or
+** if the value begins with a numeric zero.  If P is not a query
+** parameter on F or if the value of P is does not match any of the
+** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
+**
+** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
+** 64-bit signed integer and returns that integer, or D if P does not
+** exist.  If the value of P is something other than an integer, then
+** zero is returned.
+** 
+** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
+** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
+** is not a database file pathname pointer that SQLite passed into the xOpen
+** VFS method, then the behavior of this routine is undefined and probably
+** undesirable.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
+SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
+
+
+/*
+** CAPI3REF: Error Codes And Messages
+**
+** ^The sqlite3_errcode() interface returns the numeric [result code] or
 ** [extended result code] for the most recent failed sqlite3_* API call
 ** associated with a [database connection]. If a prior API call failed
 ** but the most recent API call succeeded, the return value from
-** sqlite3_errcode() is undefined.  The sqlite3_extended_errcode()
+** sqlite3_errcode() is undefined.  ^The sqlite3_extended_errcode()
 ** interface is the same except that it always returns the 
 ** [extended result code] even when extended result codes are
 ** disabled.
 **
-** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
+** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
-** Memory to hold the error message string is managed internally.
+** ^(Memory to hold the error message string is managed internally.
 ** The application does not need to worry about freeing the result.
 ** However, the error string might be overwritten or deallocated by
-** subsequent calls to other SQLite interface functions.
+** subsequent calls to other SQLite interface functions.)^
 **
 ** When the serialized [threading mode] is in use, it might be the
 ** case that a second error occurs on a separate thread in between
@@ -2715,45 +2765,14 @@ int sqlite3_open_v2(
 ** If an interface fails with SQLITE_MISUSE, that means the interface
 ** was invoked incorrectly by the application.  In that case, the
 ** error code and message may or may not be set.
-**
-** INVARIANTS:
-**
-** {H12801} The [sqlite3_errcode(D)] interface returns the numeric
-**          [result code] or [extended result code] for the most recently
-**          failed interface call associated with the [database connection] D.
-**
-** {H12802} The [sqlite3_extended_errcode(D)] interface returns the numeric
-**          [extended result code] for the most recently
-**          failed interface call associated with the [database connection] D.
-**
-** {H12803} The [sqlite3_errmsg(D)] and [sqlite3_errmsg16(D)]
-**          interfaces return English-language text that describes
-**          the error in the mostly recently failed interface call,
-**          encoded as either UTF-8 or UTF-16 respectively.
-**
-** {H12807} The strings returned by [sqlite3_errmsg()] and [sqlite3_errmsg16()]
-**          are valid until the next SQLite interface call.
-**
-** {H12808} Calls to API routines that do not return an error code
-**          (example: [sqlite3_data_count()]) do not
-**          change the error code or message returned by
-**          [sqlite3_errcode()], [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], or [sqlite3_errmsg16()].
-**
-** {H12809} Interfaces that are not associated with a specific
-**          [database connection] (examples:
-**          [sqlite3_mprintf()] or [sqlite3_enable_shared_cache()]
-**          do not change the values returned by
-**          [sqlite3_errcode()], [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg()], or [sqlite3_errmsg16()].
 */
-int sqlite3_errcode(sqlite3 *db);
-int sqlite3_extended_errcode(sqlite3 *db);
-const char *sqlite3_errmsg(sqlite3*);
-const void *sqlite3_errmsg16(sqlite3*);
+SQLITE_API int sqlite3_errcode(sqlite3 *db);
+SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
+SQLITE_API const char *sqlite3_errmsg(sqlite3*);
+SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
 
 /*
-** CAPI3REF: SQL Statement Object {H13000} <H13010>
+** CAPI3REF: SQL Statement Object
 ** KEYWORDS: {prepared statement} {prepared statements}
 **
 ** An instance of this object represents a single SQL statement.
@@ -2779,26 +2798,33 @@ const void *sqlite3_errmsg16(sqlite3*);
 typedef struct sqlite3_stmt sqlite3_stmt;
 
 /*
-** CAPI3REF: Run-time Limits {H12760} <S20600>
+** CAPI3REF: Run-time Limits
 **
-** This interface allows the size of various constructs to be limited
+** ^(This interface allows the size of various constructs to be limited
 ** on a connection by connection basis.  The first parameter is the
 ** [database connection] whose limit is to be set or queried.  The
 ** second parameter is one of the [limit categories] that define a
 ** class of constructs to be size limited.  The third parameter is the
-** new limit for that construct.  The function returns the old limit.
+** new limit for that construct.)^
 **
-** If the new limit is a negative number, the limit is unchanged.
-** For the limit category of SQLITE_LIMIT_XYZ there is a hard upper
-** bound set by a compile-time C preprocessor macro named SQLITE_MAX_XYZ.
-** (The "_LIMIT_" in the name is changed to "_MAX_".)
-** Attempts to increase a limit above its hard upper bound are
-** silently truncated to the hard upper limit.
+** ^If the new limit is a negative number, the limit is unchanged.
+** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 
+** [limits | hard upper bound]
+** set at compile-time by a C preprocessor macro called
+** [limits | SQLITE_MAX_<i>NAME</i>].
+** (The "_LIMIT_" in the name is changed to "_MAX_".))^
+** ^Attempts to increase a limit above its hard upper bound are
+** silently truncated to the hard upper bound.
 **
-** Run time limits are intended for use in applications that manage
+** ^Regardless of whether or not the limit was changed, the 
+** [sqlite3_limit()] interface returns the prior value of the limit.
+** ^Hence, to find the current value of a limit without changing it,
+** simply invoke this interface with the third parameter set to -1.
+**
+** Run-time limits are intended for use in applications that manage
 ** both their own internal database and also databases that are controlled
 ** by untrusted external sources.  An example application might be a
-** webbrowser that has its own databases for storing history and
+** web browser that has its own databases for storing history and
 ** separate databases controlled by JavaScript applications downloaded
 ** off the Internet.  The internal databases can be given the
 ** large, default limits.  Databases managed by external sources can
@@ -2809,66 +2835,59 @@ typedef struct sqlite3_stmt sqlite3_stmt;
 ** [max_page_count] [PRAGMA].
 **
 ** New run-time limit categories may be added in future releases.
-**
-** INVARIANTS:
-**
-** {H12762} A successful call to [sqlite3_limit(D,C,V)] where V is
-**          positive changes the limit on the size of construct C in the
-**          [database connection] D to the lesser of V and the hard upper
-**          bound on the size of C that is set at compile-time.
-**
-** {H12766} A successful call to [sqlite3_limit(D,C,V)] where V is negative
-**          leaves the state of the [database connection] D unchanged.
-**
-** {H12769} A successful call to [sqlite3_limit(D,C,V)] returns the
-**          value of the limit on the size of construct C in the
-**          [database connection] D as it was prior to the call.
 */
-int sqlite3_limit(sqlite3*, int id, int newVal);
+SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
 
 /*
-** CAPI3REF: Run-Time Limit Categories {H12790} <H12760>
-** KEYWORDS: {limit category} {limit categories}
+** CAPI3REF: Run-Time Limit Categories
+** KEYWORDS: {limit category} {*limit categories}
 **
-** These constants define various aspects of a [database connection]
-** that can be limited in size by calls to [sqlite3_limit()].
-** The meanings of the various limits are as follows:
+** These constants define various performance limits
+** that can be lowered at run-time using [sqlite3_limit()].
+** The synopsis of the meanings of the various limits is shown below.
+** Additional information is available at [limits | Limits in SQLite].
 **
 ** <dl>
-** <dt>SQLITE_LIMIT_LENGTH</dt>
-** <dd>The maximum size of any string or BLOB or table row.<dd>
+** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
+** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
 **
-** <dt>SQLITE_LIMIT_SQL_LENGTH</dt>
-** <dd>The maximum length of an SQL statement.</dd>
+** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
+** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
 **
-** <dt>SQLITE_LIMIT_COLUMN</dt>
+** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
 ** <dd>The maximum number of columns in a table definition or in the
-** result set of a SELECT or the maximum number of columns in an index
-** or in an ORDER BY or GROUP BY clause.</dd>
+** result set of a [SELECT] or the maximum number of columns in an index
+** or in an ORDER BY or GROUP BY clause.</dd>)^
 **
-** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
-** <dd>The maximum depth of the parse tree on any expression.</dd>
+** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
+** <dd>The maximum depth of the parse tree on any expression.</dd>)^
 **
-** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
-** <dd>The maximum number of terms in a compound SELECT statement.</dd>
+** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
+** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
 **
-** <dt>SQLITE_LIMIT_VDBE_OP</dt>
+** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
 ** <dd>The maximum number of instructions in a virtual machine program
-** used to implement an SQL statement.</dd>
+** used to implement an SQL statement.  This limit is not currently
+** enforced, though that might be added in some future release of
+** SQLite.</dd>)^
 **
-** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
-** <dd>The maximum number of arguments on a function.</dd>
+** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
+** <dd>The maximum number of arguments on a function.</dd>)^
 **
-** <dt>SQLITE_LIMIT_ATTACHED</dt>
-** <dd>The maximum number of attached databases.</dd>
+** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
+** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
 **
-** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
-** <dd>The maximum length of the pattern argument to the LIKE or
-** GLOB operators.</dd>
+** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
+** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
+** <dd>The maximum length of the pattern argument to the [LIKE] or
+** [GLOB] operators.</dd>)^
 **
-** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
-** <dd>The maximum number of variables in an SQL statement that can
-** be bound.</dd>
+** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
+** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
+** <dd>The maximum index number of any [parameter] in an SQL statement.)^
+**
+** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
+** <dd>The maximum depth of recursion for triggers.</dd>)^
 ** </dl>
 */
 #define SQLITE_LIMIT_LENGTH                    0
@@ -2881,134 +2900,111 @@ int sqlite3_limit(sqlite3*, int id, int newVal);
 #define SQLITE_LIMIT_ATTACHED                  7
 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
+#define SQLITE_LIMIT_TRIGGER_DEPTH            10
 
 /*
-** CAPI3REF: Compiling An SQL Statement {H13010} <S10000>
+** CAPI3REF: Compiling An SQL Statement
 ** KEYWORDS: {SQL statement compiler}
 **
 ** To execute an SQL query, it must first be compiled into a byte-code
 ** program using one of these routines.
 **
 ** The first argument, "db", is a [database connection] obtained from a
-** prior call to [sqlite3_open()], [sqlite3_open_v2()] or [sqlite3_open16()].
+** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
+** [sqlite3_open16()].  The database connection must not have been closed.
 **
 ** The second argument, "zSql", is the statement to be compiled, encoded
 ** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
 ** use UTF-16.
 **
-** If the nByte argument is less than zero, then zSql is read up to the
-** first zero terminator. If nByte is non-negative, then it is the maximum
-** number of  bytes read from zSql.  When nByte is non-negative, the
+** ^If the nByte argument is less than zero, then zSql is read up to the
+** first zero terminator. ^If nByte is non-negative, then it is the maximum
+** number of  bytes read from zSql.  ^When nByte is non-negative, the
 ** zSql string ends at either the first '\000' or '\u0000' character or
 ** the nByte-th byte, whichever comes first. If the caller knows
 ** that the supplied string is nul-terminated, then there is a small
 ** performance advantage to be gained by passing an nByte parameter that
 ** is equal to the number of bytes in the input string <i>including</i>
-** the nul-terminator bytes.
+** the nul-terminator bytes as this saves SQLite from having to
+** make a copy of the input string.
 **
-** *pzTail is made to point to the first byte past the end of the
-** first SQL statement in zSql.  These routines only compile the first
-** statement in zSql, so *pzTail is left pointing to what remains
-** uncompiled.
+** ^If pzTail is not NULL then *pzTail is made to point to the first byte
+** past the end of the first SQL statement in zSql.  These routines only
+** compile the first statement in zSql, so *pzTail is left pointing to
+** what remains uncompiled.
 **
-** *ppStmt is left pointing to a compiled [prepared statement] that can be
-** executed using [sqlite3_step()].  If there is an error, *ppStmt is set
-** to NULL.  If the input text contains no SQL (if the input is an empty
+** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
+** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
+** to NULL.  ^If the input text contains no SQL (if the input is an empty
 ** string or a comment) then *ppStmt is set to NULL.
-** {A13018} The calling procedure is responsible for deleting the compiled
+** The calling procedure is responsible for deleting the compiled
 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
+** ppStmt may not be NULL.
 **
-** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned.
+** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
+** otherwise an [error code] is returned.
 **
 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
 ** recommended for all new programs. The two older interfaces are retained
 ** for backwards compatibility, but their use is discouraged.
-** In the "v2" interfaces, the prepared statement
+** ^In the "v2" interfaces, the prepared statement
 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
 ** original SQL text. This causes the [sqlite3_step()] interface to
-** behave a differently in two ways:
+** behave differently in three ways:
 **
 ** <ol>
 ** <li>
-** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
+** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
-** statement and try to run it again.  If the schema has changed in
-** a way that makes the statement no longer valid, [sqlite3_step()] will still
-** return [SQLITE_SCHEMA].  But unlike the legacy behavior, [SQLITE_SCHEMA] is
-** now a fatal error.  Calling [sqlite3_prepare_v2()] again will not make the
-** error go away.  Note: use [sqlite3_errmsg()] to find the text
-** of the parsing error that results in an [SQLITE_SCHEMA] return.
+** statement and try to run it again.
 ** </li>
 **
 ** <li>
-** When an error occurs, [sqlite3_step()] will return one of the detailed
-** [error codes] or [extended error codes].  The legacy behavior was that
+** ^When an error occurs, [sqlite3_step()] will return one of the detailed
+** [error codes] or [extended error codes].  ^The legacy behavior was that
 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
-** and you would have to make a second call to [sqlite3_reset()] in order
-** to find the underlying cause of the problem. With the "v2" prepare
+** and the application would have to make a second call to [sqlite3_reset()]
+** in order to find the underlying cause of the problem. With the "v2" prepare
 ** interfaces, the underlying reason for the error is returned immediately.
 ** </li>
+**
+** <li>
+** ^If the specific value bound to [parameter | host parameter] in the 
+** WHERE clause might influence the choice of query plan for a statement,
+** then the statement will be automatically recompiled, as if there had been 
+** a schema change, on the first  [sqlite3_step()] call following any change
+** to the [sqlite3_bind_text | bindings] of that [parameter]. 
+** ^The specific value of WHERE-clause [parameter] might influence the 
+** choice of query plan if the parameter is the left-hand side of a [LIKE]
+** or [GLOB] operator or if the parameter is compared to an indexed column
+** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
+** the 
+** </li>
 ** </ol>
-**
-** INVARIANTS:
-**
-** {H13011} The [sqlite3_prepare(db,zSql,...)] and
-**          [sqlite3_prepare_v2(db,zSql,...)] interfaces interpret the
-**          text in their zSql parameter as UTF-8.
-**
-** {H13012} The [sqlite3_prepare16(db,zSql,...)] and
-**          [sqlite3_prepare16_v2(db,zSql,...)] interfaces interpret the
-**          text in their zSql parameter as UTF-16 in the native byte order.
-**
-** {H13013} If the nByte argument to [sqlite3_prepare_v2(db,zSql,nByte,...)]
-**          and its variants is less than zero, the SQL text is
-**          read from zSql is read up to the first zero terminator.
-**
-** {H13014} If the nByte argument to [sqlite3_prepare_v2(db,zSql,nByte,...)]
-**          and its variants is non-negative, then at most nBytes bytes of
-**          SQL text is read from zSql.
-**
-** {H13015} In [sqlite3_prepare_v2(db,zSql,N,P,pzTail)] and its variants
-**          if the zSql input text contains more than one SQL statement
-**          and pzTail is not NULL, then *pzTail is made to point to the
-**          first byte past the end of the first SQL statement in zSql.
-**          <todo>What does *pzTail point to if there is one statement?</todo>
-**
-** {H13016} A successful call to [sqlite3_prepare_v2(db,zSql,N,ppStmt,...)]
-**          or one of its variants writes into *ppStmt a pointer to a new
-**          [prepared statement] or a pointer to NULL if zSql contains
-**          nothing other than whitespace or comments.
-**
-** {H13019} The [sqlite3_prepare_v2()] interface and its variants return
-**          [SQLITE_OK] or an appropriate [error code] upon failure.
-**
-** {H13021} Before [sqlite3_prepare(db,zSql,nByte,ppStmt,pzTail)] or its
-**          variants returns an error (any value other than [SQLITE_OK]),
-**          they first set *ppStmt to NULL.
 */
-int sqlite3_prepare(
+SQLITE_API int sqlite3_prepare(
   sqlite3 *db,            /* Database handle */
   const char *zSql,       /* SQL statement, UTF-8 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
-int sqlite3_prepare_v2(
+SQLITE_API int sqlite3_prepare_v2(
   sqlite3 *db,            /* Database handle */
   const char *zSql,       /* SQL statement, UTF-8 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
-int sqlite3_prepare16(
+SQLITE_API int sqlite3_prepare16(
   sqlite3 *db,            /* Database handle */
   const void *zSql,       /* SQL statement, UTF-16 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
-int sqlite3_prepare16_v2(
+SQLITE_API int sqlite3_prepare16_v2(
   sqlite3 *db,            /* Database handle */
   const void *zSql,       /* SQL statement, UTF-16 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
@@ -3017,36 +3013,71 @@ int sqlite3_prepare16_v2(
 );
 
 /*
-** CAPI3REF: Retrieving Statement SQL {H13100} <H13000>
+** CAPI3REF: Retrieving Statement SQL
 **
-** This interface can be used to retrieve a saved copy of the original
+** ^This interface can be used to retrieve a saved copy of the original
 ** SQL text used to create a [prepared statement] if that statement was
 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
-**
-** INVARIANTS:
-**
-** {H13101} If the [prepared statement] passed as the argument to
-**          [sqlite3_sql()] was compiled using either [sqlite3_prepare_v2()] or
-**          [sqlite3_prepare16_v2()], then [sqlite3_sql()] returns
-**          a pointer to a zero-terminated string containing a UTF-8 rendering
-**          of the original SQL statement.
-**
-** {H13102} If the [prepared statement] passed as the argument to
-**          [sqlite3_sql()] was compiled using either [sqlite3_prepare()] or
-**          [sqlite3_prepare16()], then [sqlite3_sql()] returns a NULL pointer.
-**
-** {H13103} The string returned by [sqlite3_sql(S)] is valid until the
-**          [prepared statement] S is deleted using [sqlite3_finalize(S)].
 */
-const char *sqlite3_sql(sqlite3_stmt *pStmt);
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200>
+** CAPI3REF: Determine If An SQL Statement Writes The Database
+**
+** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
+** and only if the [prepared statement] X makes no direct changes to
+** the content of the database file.
+**
+** Note that [application-defined SQL functions] or
+** [virtual tables] might change the database indirectly as a side effect.  
+** ^(For example, if an application defines a function "eval()" that 
+** calls [sqlite3_exec()], then the following SQL statement would
+** change the database file through side-effects:
+**
+** <blockquote><pre>
+**    SELECT eval('DELETE FROM t1') FROM t2;
+** </pre></blockquote>
+**
+** But because the [SELECT] statement does not change the database file
+** directly, sqlite3_stmt_readonly() would still return true.)^
+**
+** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
+** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
+** since the statements themselves do not actually modify the database but
+** rather they control the timing of when other statements modify the 
+** database.  ^The [ATTACH] and [DETACH] statements also cause
+** sqlite3_stmt_readonly() to return true since, while those statements
+** change the configuration of a database connection, they do not make 
+** changes to the content of the database files on disk.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Determine If A Prepared Statement Has Been Reset
+**
+** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
+** [prepared statement] S has been stepped at least once using 
+** [sqlite3_step(S)] but has not run to completion and/or has not 
+** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
+** interface returns false if S is a NULL pointer.  If S is not a 
+** NULL pointer and is not a pointer to a valid [prepared statement]
+** object, then the behavior is undefined and probably undesirable.
+**
+** This interface can be used in combination [sqlite3_next_stmt()]
+** to locate all prepared statements associated with a database 
+** connection that are in need of being reset.  This can be used,
+** for example, in diagnostic routines to search for prepared 
+** statements that are holding a transaction open.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Dynamically Typed Value Object
 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
 **
 ** SQLite uses the sqlite3_value object to represent all values
 ** that can be stored in a database table. SQLite uses dynamic typing
-** for the values it stores. Values stored in sqlite3_value objects
+** for the values it stores.  ^Values stored in sqlite3_value objects
 ** can be integers, floating point values, strings, BLOBs, or NULL.
 **
 ** An sqlite3_value object may be either "protected" or "unprotected".
@@ -3056,7 +3087,7 @@ const char *sqlite3_sql(sqlite3_stmt *pStmt);
 ** whether or not it requires a protected sqlite3_value.
 **
 ** The terms "protected" and "unprotected" refer to whether or not
-** a mutex is held.  A internal mutex is held for a protected
+** a mutex is held.  An internal mutex is held for a protected
 ** sqlite3_value object but no mutex is held for an unprotected
 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
@@ -3065,12 +3096,12 @@ const char *sqlite3_sql(sqlite3_stmt *pStmt);
 ** then there is no distinction between protected and unprotected
 ** sqlite3_value objects and they can be used interchangeably.  However,
 ** for maximum code portability it is recommended that applications
-** still make the distinction between between protected and unprotected
+** still make the distinction between protected and unprotected
 ** sqlite3_value objects even when not strictly required.
 **
-** The sqlite3_value objects that are passed as parameters into the
+** ^The sqlite3_value objects that are passed as parameters into the
 ** implementation of [application-defined SQL functions] are protected.
-** The sqlite3_value object returned by
+** ^The sqlite3_value object returned by
 ** [sqlite3_column_value()] is unprotected.
 ** Unprotected sqlite3_value objects may only be used with
 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
@@ -3080,10 +3111,10 @@ const char *sqlite3_sql(sqlite3_stmt *pStmt);
 typedef struct Mem sqlite3_value;
 
 /*
-** CAPI3REF: SQL Function Context Object {H16001} <S20200>
+** CAPI3REF: SQL Function Context Object
 **
 ** The context in which an SQL function executes is stored in an
-** sqlite3_context object.  A pointer to an sqlite3_context object
+** sqlite3_context object.  ^A pointer to an sqlite3_context object
 ** is always first parameter to [application-defined SQL functions].
 ** The application-defined SQL function implementation will pass this
 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
@@ -3094,12 +3125,13 @@ typedef struct Mem sqlite3_value;
 typedef struct sqlite3_context sqlite3_context;
 
 /*
-** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300>
+** CAPI3REF: Binding Values To Prepared Statements
 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
 **
-** In the SQL strings input to [sqlite3_prepare_v2()] and its variants,
-** literals may be replaced by a parameter in one of these forms:
+** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
+** literals may be replaced by a [parameter] that matches one of following
+** templates:
 **
 ** <ul>
 ** <li>  ?
@@ -3109,196 +3141,128 @@ typedef struct sqlite3_context sqlite3_context;
 ** <li>  $VVV
 ** </ul>
 **
-** In the parameter forms shown above NNN is an integer literal,
-** and VVV is an alpha-numeric parameter name. The values of these
+** In the templates above, NNN represents an integer literal,
+** and VVV represents an alphanumeric identifier.)^  ^The values of these
 ** parameters (also called "host parameter names" or "SQL parameters")
 ** can be set using the sqlite3_bind_*() routines defined here.
 **
-** The first argument to the sqlite3_bind_*() routines is always
+** ^The first argument to the sqlite3_bind_*() routines is always
 ** a pointer to the [sqlite3_stmt] object returned from
 ** [sqlite3_prepare_v2()] or its variants.
 **
-** The second argument is the index of the SQL parameter to be set.
-** The leftmost SQL parameter has an index of 1.  When the same named
+** ^The second argument is the index of the SQL parameter to be set.
+** ^The leftmost SQL parameter has an index of 1.  ^When the same named
 ** SQL parameter is used more than once, second and subsequent
 ** occurrences have the same index as the first occurrence.
-** The index for named parameters can be looked up using the
-** [sqlite3_bind_parameter_index()] API if desired.  The index
+** ^The index for named parameters can be looked up using the
+** [sqlite3_bind_parameter_index()] API if desired.  ^The index
 ** for "?NNN" parameters is the value of NNN.
-** The NNN value must be between 1 and the [sqlite3_limit()]
+** ^The NNN value must be between 1 and the [sqlite3_limit()]
 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
 **
-** The third argument is the value to bind to the parameter.
+** ^The third argument is the value to bind to the parameter.
 **
-** In those routines that have a fourth argument, its value is the
+** ^(In those routines that have a fourth argument, its value is the
 ** number of bytes in the parameter.  To be clear: the value is the
-** number of <u>bytes</u> in the value, not the number of characters.
-** If the fourth parameter is negative, the length of the string is
+** number of <u>bytes</u> in the value, not the number of characters.)^
+** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** is negative, then the length of the string is
 ** the number of bytes up to the first zero terminator.
+** If the fourth parameter to sqlite3_bind_blob() is negative, then
+** the behavior is undefined.
+** If a non-negative fourth parameter is provided to sqlite3_bind_text()
+** or sqlite3_bind_text16() then that parameter must be the byte offset
+** where the NUL terminator would occur assuming the string were NUL
+** terminated.  If any NUL characters occur at byte offsets less than 
+** the value of the fourth parameter then the resulting string value will
+** contain embedded NULs.  The result of expressions involving strings
+** with embedded NULs is undefined.
 **
-** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
+** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
-** string after SQLite has finished with it. If the fifth argument is
+** string after SQLite has finished with it.  ^The destructor is called
+** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
+** sqlite3_bind_text(), or sqlite3_bind_text16() fails.  
+** ^If the fifth argument is
 ** the special value [SQLITE_STATIC], then SQLite assumes that the
 ** information is in static, unmanaged space and does not need to be freed.
-** If the fifth argument has the value [SQLITE_TRANSIENT], then
+** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
 ** SQLite makes its own private copy of the data immediately, before
 ** the sqlite3_bind_*() routine returns.
 **
-** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
-** is filled with zeroes.  A zeroblob uses a fixed amount of memory
+** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
+** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
 ** (just an integer to hold its size) while it is being processed.
 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
 ** content is later written using
 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
-** A negative value for the zeroblob results in a zero-length BLOB.
+** ^A negative value for the zeroblob results in a zero-length BLOB.
 **
-** The sqlite3_bind_*() routines must be called after
-** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
-** before [sqlite3_step()].
-** Bindings are not cleared by the [sqlite3_reset()] routine.
-** Unbound parameters are interpreted as NULL.
+** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
+** for the [prepared statement] or with a prepared statement for which
+** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
+** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
+** routine is passed a [prepared statement] that has been finalized, the
+** result is undefined and probably harmful.
 **
-** These routines return [SQLITE_OK] on success or an error code if
-** anything goes wrong.  [SQLITE_RANGE] is returned if the parameter
-** index is out of range.  [SQLITE_NOMEM] is returned if malloc() fails.
-** [SQLITE_MISUSE] might be returned if these routines are called on a
-** virtual machine that is the wrong state or which has already been finalized.
-** Detection of misuse is unreliable.  Applications should not depend
-** on SQLITE_MISUSE returns.  SQLITE_MISUSE is intended to indicate a
-** a logic error in the application.  Future versions of SQLite might
-** panic rather than return SQLITE_MISUSE.
+** ^Bindings are not cleared by the [sqlite3_reset()] routine.
+** ^Unbound parameters are interpreted as NULL.
+**
+** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
+** [error code] if anything goes wrong.
+** ^[SQLITE_RANGE] is returned if the parameter
+** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
 **
 ** See also: [sqlite3_bind_parameter_count()],
 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13506} The [SQL statement compiler] recognizes tokens of the forms
-**          "?", "?NNN", "$VVV", ":VVV", and "@VVV" as SQL parameters,
-**          where NNN is any sequence of one or more digits
-**          and where VVV is any sequence of one or more alphanumeric
-**          characters or "::" optionally followed by a string containing
-**          no spaces and contained within parentheses.
-**
-** {H13509} The initial value of an SQL parameter is NULL.
-**
-** {H13512} The index of an "?" SQL parameter is one larger than the
-**          largest index of SQL parameter to the left, or 1 if
-**          the "?" is the leftmost SQL parameter.
-**
-** {H13515} The index of an "?NNN" SQL parameter is the integer NNN.
-**
-** {H13518} The index of an ":VVV", "$VVV", or "@VVV" SQL parameter is
-**          the same as the index of leftmost occurrences of the same
-**          parameter, or one more than the largest index over all
-**          parameters to the left if this is the first occurrence
-**          of this parameter, or 1 if this is the leftmost parameter.
-**
-** {H13521} The [SQL statement compiler] fails with an [SQLITE_RANGE]
-**          error if the index of an SQL parameter is less than 1
-**          or greater than the compile-time SQLITE_MAX_VARIABLE_NUMBER
-**          parameter.
-**
-** {H13524} Calls to [sqlite3_bind_text | sqlite3_bind(S,N,V,...)]
-**          associate the value V with all SQL parameters having an
-**          index of N in the [prepared statement] S.
-**
-** {H13527} Calls to [sqlite3_bind_text | sqlite3_bind(S,N,...)]
-**          override prior calls with the same values of S and N.
-**
-** {H13530} Bindings established by [sqlite3_bind_text | sqlite3_bind(S,...)]
-**          persist across calls to [sqlite3_reset(S)].
-**
-** {H13533} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] SQLite binds the first L
-**          bytes of the BLOB or string pointed to by V, when L
-**          is non-negative.
-**
-** {H13536} In calls to [sqlite3_bind_text(S,N,V,L,D)] or
-**          [sqlite3_bind_text16(S,N,V,L,D)] SQLite binds characters
-**          from V through the first zero character when L is negative.
-**
-** {H13539} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] when D is the special
-**          constant [SQLITE_STATIC], SQLite assumes that the value V
-**          is held in static unmanaged space that will not change
-**          during the lifetime of the binding.
-**
-** {H13542} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] when D is the special
-**          constant [SQLITE_TRANSIENT], the routine makes a
-**          private copy of the value V before it returns.
-**
-** {H13545} In calls to [sqlite3_bind_blob(S,N,V,L,D)],
-**          [sqlite3_bind_text(S,N,V,L,D)], or
-**          [sqlite3_bind_text16(S,N,V,L,D)] when D is a pointer to
-**          a function, SQLite invokes that function to destroy the
-**          value V after it has finished using the value V.
-**
-** {H13548} In calls to [sqlite3_bind_zeroblob(S,N,V,L)] the value bound
-**          is a BLOB of L bytes, or a zero-length BLOB if L is negative.
-**
-** {H13551} In calls to [sqlite3_bind_value(S,N,V)] the V argument may
-**          be either a [protected sqlite3_value] object or an
-**          [unprotected sqlite3_value] object.
 */
-int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
-int sqlite3_bind_double(sqlite3_stmt*, int, double);
-int sqlite3_bind_int(sqlite3_stmt*, int, int);
-int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
-int sqlite3_bind_null(sqlite3_stmt*, int);
-int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
-int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
-int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
-int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
+SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
+SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
 
 /*
-** CAPI3REF: Number Of SQL Parameters {H13600} <S70300>
+** CAPI3REF: Number Of SQL Parameters
 **
-** This routine can be used to find the number of [SQL parameters]
+** ^This routine can be used to find the number of [SQL parameters]
 ** in a [prepared statement].  SQL parameters are tokens of the
 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
 ** placeholders for values that are [sqlite3_bind_blob | bound]
 ** to the parameters at a later time.
 **
-** This routine actually returns the index of the largest (rightmost)
+** ^(This routine actually returns the index of the largest (rightmost)
 ** parameter. For all forms except ?NNN, this will correspond to the
-** number of unique parameters.  If parameters of the ?NNN are used,
-** there may be gaps in the list.
+** number of unique parameters.  If parameters of the ?NNN form are used,
+** there may be gaps in the list.)^
 **
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_name()], and
 ** [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13601} The [sqlite3_bind_parameter_count(S)] interface returns
-**          the largest index of all SQL parameters in the
-**          [prepared statement] S, or 0 if S contains no SQL parameters.
 */
-int sqlite3_bind_parameter_count(sqlite3_stmt*);
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Name Of A Host Parameter {H13620} <S70300>
+** CAPI3REF: Name Of A Host Parameter
 **
-** This routine returns a pointer to the name of the n-th
-** [SQL parameter] in a [prepared statement].
-** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** ^The sqlite3_bind_parameter_name(P,N) interface returns
+** the name of the N-th [SQL parameter] in the [prepared statement] P.
+** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
 ** respectively.
 ** In other words, the initial ":" or "$" or "@" or "?"
-** is included as part of the name.
-** Parameters of the form "?" without a following integer have no name
-** and are also referred to as "anonymous parameters".
+** is included as part of the name.)^
+** ^Parameters of the form "?" without a following integer have no name
+** and are referred to as "nameless" or "anonymous parameters".
 **
-** The first host parameter has an index of 1, not 0.
+** ^The first host parameter has an index of 1, not 0.
 **
-** If the value n is out of range or if the n-th parameter is
-** nameless, then NULL is returned.  The returned string is
+** ^If the value N is out of range or if the N-th parameter is
+** nameless, then NULL is returned.  ^The returned string is
 ** always in UTF-8 encoding even if the named parameter was
 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
 ** [sqlite3_prepare16_v2()].
@@ -3306,234 +3270,138 @@ int sqlite3_bind_parameter_count(sqlite3_stmt*);
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_count()], and
 ** [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13621} The [sqlite3_bind_parameter_name(S,N)] interface returns
-**          a UTF-8 rendering of the name of the SQL parameter in
-**          the [prepared statement] S having index N, or
-**          NULL if there is no SQL parameter with index N or if the
-**          parameter with index N is an anonymous parameter "?".
 */
-const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
 
 /*
-** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300>
+** CAPI3REF: Index Of A Parameter With A Given Name
 **
-** Return the index of an SQL parameter given its name.  The
+** ^Return the index of an SQL parameter given its name.  ^The
 ** index value returned is suitable for use as the second
-** parameter to [sqlite3_bind_blob|sqlite3_bind()].  A zero
-** is returned if no matching parameter is found.  The parameter
+** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
+** is returned if no matching parameter is found.  ^The parameter
 ** name must be given in UTF-8 even if the original statement
 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
 **
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_count()], and
 ** [sqlite3_bind_parameter_index()].
-**
-** INVARIANTS:
-**
-** {H13641} The [sqlite3_bind_parameter_index(S,N)] interface returns
-**          the index of SQL parameter in the [prepared statement]
-**          S whose name matches the UTF-8 string N, or 0 if there is
-**          no match.
 */
-int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
 
 /*
-** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300>
+** CAPI3REF: Reset All Bindings On A Prepared Statement
 **
-** Contrary to the intuition of many, [sqlite3_reset()] does not reset
+** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
-** Use this routine to reset all host parameters to NULL.
-**
-** INVARIANTS:
-**
-** {H13661} The [sqlite3_clear_bindings(S)] interface resets all SQL
-**          parameter bindings in the [prepared statement] S back to NULL.
+** ^Use this routine to reset all host parameters to NULL.
 */
-int sqlite3_clear_bindings(sqlite3_stmt*);
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700>
+** CAPI3REF: Number Of Columns In A Result Set
 **
-** Return the number of columns in the result set returned by the
-** [prepared statement]. This routine returns 0 if pStmt is an SQL
+** ^Return the number of columns in the result set returned by the
+** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
 ** statement that does not return data (for example an [UPDATE]).
 **
-** INVARIANTS:
-**
-** {H13711} The [sqlite3_column_count(S)] interface returns the number of
-**          columns in the result set generated by the [prepared statement] S,
-**          or 0 if S does not generate a result set.
+** See also: [sqlite3_data_count()]
 */
-int sqlite3_column_count(sqlite3_stmt *pStmt);
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Column Names In A Result Set {H13720} <S10700>
+** CAPI3REF: Column Names In A Result Set
 **
-** These routines return the name assigned to a particular column
-** in the result set of a [SELECT] statement.  The sqlite3_column_name()
+** ^These routines return the name assigned to a particular column
+** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
 ** interface returns a pointer to a zero-terminated UTF-8 string
 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
-** UTF-16 string.  The first parameter is the [prepared statement]
-** that implements the [SELECT] statement. The second parameter is the
-** column number.  The leftmost column is number 0.
+** UTF-16 string.  ^The first parameter is the [prepared statement]
+** that implements the [SELECT] statement. ^The second parameter is the
+** column number.  ^The leftmost column is number 0.
 **
-** The returned string pointer is valid until either the [prepared statement]
-** is destroyed by [sqlite3_finalize()] or until the next call to
+** ^The returned string pointer is valid until either the [prepared statement]
+** is destroyed by [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the next call to
 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
 **
-** If sqlite3_malloc() fails during the processing of either routine
+** ^If sqlite3_malloc() fails during the processing of either routine
 ** (for example during a conversion from UTF-8 to UTF-16) then a
 ** NULL pointer is returned.
 **
-** The name of a result column is the value of the "AS" clause for
+** ^The name of a result column is the value of the "AS" clause for
 ** that column, if there is an AS clause.  If there is no AS clause
 ** then the name of the column is unspecified and may change from
 ** one release of SQLite to the next.
-**
-** INVARIANTS:
-**
-** {H13721} A successful invocation of the [sqlite3_column_name(S,N)]
-**          interface returns the name of the Nth column (where 0 is
-**          the leftmost column) for the result set of the
-**          [prepared statement] S as a zero-terminated UTF-8 string.
-**
-** {H13723} A successful invocation of the [sqlite3_column_name16(S,N)]
-**          interface returns the name of the Nth column (where 0 is
-**          the leftmost column) for the result set of the
-**          [prepared statement] S as a zero-terminated UTF-16 string
-**          in the native byte order.
-**
-** {H13724} The [sqlite3_column_name()] and [sqlite3_column_name16()]
-**          interfaces return a NULL pointer if they are unable to
-**          allocate memory to hold their normal return strings.
-**
-** {H13725} If the N parameter to [sqlite3_column_name(S,N)] or
-**          [sqlite3_column_name16(S,N)] is out of range, then the
-**          interfaces return a NULL pointer.
-**
-** {H13726} The strings returned by [sqlite3_column_name(S,N)] and
-**          [sqlite3_column_name16(S,N)] are valid until the next
-**          call to either routine with the same S and N parameters
-**          or until [sqlite3_finalize(S)] is called.
-**
-** {H13727} When a result column of a [SELECT] statement contains
-**          an AS clause, the name of that column is the identifier
-**          to the right of the AS keyword.
 */
-const char *sqlite3_column_name(sqlite3_stmt*, int N);
-const void *sqlite3_column_name16(sqlite3_stmt*, int N);
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
 
 /*
-** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700>
+** CAPI3REF: Source Of Data In A Query Result
 **
-** These routines provide a means to determine what column of what
-** table in which database a result of a [SELECT] statement comes from.
-** The name of the database or table or column can be returned as
-** either a UTF-8 or UTF-16 string.  The _database_ routines return
+** ^These routines provide a means to determine the database, table, and
+** table column that is the origin of a particular result column in
+** [SELECT] statement.
+** ^The name of the database or table or column can be returned as
+** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
 ** the database name, the _table_ routines return the table name, and
 ** the origin_ routines return the column name.
-** The returned string is valid until the [prepared statement] is destroyed
-** using [sqlite3_finalize()] or until the same information is requested
+** ^The returned string is valid until the [prepared statement] is destroyed
+** using [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the same information is requested
 ** again in a different encoding.
 **
-** The names returned are the original un-aliased names of the
+** ^The names returned are the original un-aliased names of the
 ** database, table, and column.
 **
-** The first argument to the following calls is a [prepared statement].
-** These functions return information about the Nth column returned by
+** ^The first argument to these interfaces is a [prepared statement].
+** ^These functions return information about the Nth result column returned by
 ** the statement, where N is the second function argument.
+** ^The left-most column is column 0 for these routines.
 **
-** If the Nth column returned by the statement is an expression or
+** ^If the Nth column returned by the statement is an expression or
 ** subquery and is not a column value, then all of these functions return
-** NULL.  These routine might also return NULL if a memory allocation error
-** occurs.  Otherwise, they return the name of the attached database, table
-** and column that query result column was extracted from.
+** NULL.  ^These routine might also return NULL if a memory allocation error
+** occurs.  ^Otherwise, they return the name of the attached database, table,
+** or column that query result column was extracted from.
 **
-** As with all other SQLite APIs, those postfixed with "16" return
-** UTF-16 encoded strings, the other functions return UTF-8. {END}
+** ^As with all other SQLite APIs, those whose names end with "16" return
+** UTF-16 encoded strings and the other functions return UTF-8.
 **
-** These APIs are only available if the library was compiled with the
-** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
+** ^These APIs are only available if the library was compiled with the
+** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
 **
-** {A13751}
 ** If two or more threads call one or more of these routines against the same
 ** prepared statement and column at the same time then the results are
 ** undefined.
 **
-** INVARIANTS:
-**
-** {H13741} The [sqlite3_column_database_name(S,N)] interface returns either
-**          the UTF-8 zero-terminated name of the database from which the
-**          Nth result column of the [prepared statement] S is extracted,
-**          or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13742} The [sqlite3_column_database_name16(S,N)] interface returns either
-**          the UTF-16 native byte order zero-terminated name of the database
-**          from which the Nth result column of the [prepared statement] S is
-**          extracted, or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13743} The [sqlite3_column_table_name(S,N)] interface returns either
-**          the UTF-8 zero-terminated name of the table from which the
-**          Nth result column of the [prepared statement] S is extracted,
-**          or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13744} The [sqlite3_column_table_name16(S,N)] interface returns either
-**          the UTF-16 native byte order zero-terminated name of the table
-**          from which the Nth result column of the [prepared statement] S is
-**          extracted, or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13745} The [sqlite3_column_origin_name(S,N)] interface returns either
-**          the UTF-8 zero-terminated name of the table column from which the
-**          Nth result column of the [prepared statement] S is extracted,
-**          or NULL if the Nth column of S is a general expression
-**          or if unable to allocate memory to store the name.
-**
-** {H13746} The [sqlite3_column_origin_name16(S,N)] interface returns either
-**          the UTF-16 native byte order zero-terminated name of the table
-**          column from which the Nth result column of the
-**          [prepared statement] S is extracted, or NULL if the Nth column
-**          of S is a general expression or if unable to allocate memory
-**          to store the name.
-**
-** {H13748} The return values from
-**          [sqlite3_column_database_name | column metadata interfaces]
-**          are valid for the lifetime of the [prepared statement]
-**          or until the encoding is changed by another metadata
-**          interface call for the same prepared statement and column.
-**
-** ASSUMPTIONS:
-**
-** {A13751} If two or more threads call one or more
-**          [sqlite3_column_database_name | column metadata interfaces]
-**          for the same [prepared statement] and result column
-**          at the same time then the results are undefined.
+** If two or more threads call one or more
+** [sqlite3_column_database_name | column metadata interfaces]
+** for the same [prepared statement] and result column
+** at the same time then the results are undefined.
 */
-const char *sqlite3_column_database_name(sqlite3_stmt*,int);
-const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
-const char *sqlite3_column_table_name(sqlite3_stmt*,int);
-const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
-const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
-const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
 
 /*
-** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700>
+** CAPI3REF: Declared Datatype Of A Query Result
 **
-** The first parameter is a [prepared statement].
+** ^(The first parameter is a [prepared statement].
 ** If this statement is a [SELECT] statement and the Nth column of the
 ** returned result set of that [SELECT] is a table column (not an
 ** expression or subquery) then the declared type of the table
-** column is returned.  If the Nth column of the result set is an
+** column is returned.)^  ^If the Nth column of the result set is an
 ** expression or subquery, then a NULL pointer is returned.
-** The returned string is always UTF-8 encoded. {END}
+** ^The returned string is always UTF-8 encoded.
 **
-** For example, given the database schema:
+** ^(For example, given the database schema:
 **
 ** CREATE TABLE t1(c1 VARIANT);
 **
@@ -3542,41 +3410,20 @@ const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
 ** SELECT c1 + 1, c1 FROM t1;
 **
 ** this routine would return the string "VARIANT" for the second result
-** column (i==1), and a NULL pointer for the first result column (i==0).
+** column (i==1), and a NULL pointer for the first result column (i==0).)^
 **
-** SQLite uses dynamic run-time typing.  So just because a column
+** ^SQLite uses dynamic run-time typing.  ^So just because a column
 ** is declared to contain a particular type does not mean that the
 ** data stored in that column is of the declared type.  SQLite is
-** strongly typed, but the typing is dynamic not static.  Type
+** strongly typed, but the typing is dynamic not static.  ^Type
 ** is associated with individual values, not with the containers
 ** used to hold those values.
-**
-** INVARIANTS:
-**
-** {H13761}  A successful call to [sqlite3_column_decltype(S,N)] returns a
-**           zero-terminated UTF-8 string containing the declared datatype
-**           of the table column that appears as the Nth column (numbered
-**           from 0) of the result set to the [prepared statement] S.
-**
-** {H13762}  A successful call to [sqlite3_column_decltype16(S,N)]
-**           returns a zero-terminated UTF-16 native byte order string
-**           containing the declared datatype of the table column that appears
-**           as the Nth column (numbered from 0) of the result set to the
-**           [prepared statement] S.
-**
-** {H13763}  If N is less than 0 or N is greater than or equal to
-**           the number of columns in the [prepared statement] S,
-**           or if the Nth column of S is an expression or subquery rather
-**           than a table column, or if a memory allocation failure
-**           occurs during encoding conversions, then
-**           calls to [sqlite3_column_decltype(S,N)] or
-**           [sqlite3_column_decltype16(S,N)] return NULL.
 */
-const char *sqlite3_column_decltype(sqlite3_stmt*,int);
-const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 
 /*
-** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000>
+** CAPI3REF: Evaluate An SQL Statement
 **
 ** After a [prepared statement] has been prepared using either
 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
@@ -3590,35 +3437,35 @@ const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 ** new "v2" interface is recommended for new applications but the legacy
 ** interface will continue to be supported.
 **
-** In the legacy interface, the return value will be either [SQLITE_BUSY],
+** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
-** With the "v2" interface, any of the other [result codes] or
+** ^With the "v2" interface, any of the other [result codes] or
 ** [extended result codes] might be returned as well.
 **
-** [SQLITE_BUSY] means that the database engine was unable to acquire the
-** database locks it needs to do its job.  If the statement is a [COMMIT]
+** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
+** database locks it needs to do its job.  ^If the statement is a [COMMIT]
 ** or occurs outside of an explicit transaction, then you can retry the
-** statement.  If the statement is not a [COMMIT] and occurs within a
+** statement.  If the statement is not a [COMMIT] and occurs within an
 ** explicit transaction then you should rollback the transaction before
 ** continuing.
 **
-** [SQLITE_DONE] means that the statement has finished executing
+** ^[SQLITE_DONE] means that the statement has finished executing
 ** successfully.  sqlite3_step() should not be called again on this virtual
 ** machine without first calling [sqlite3_reset()] to reset the virtual
 ** machine back to its initial state.
 **
-** If the SQL statement being executed returns any data, then [SQLITE_ROW]
+** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
 ** is returned each time a new row of data is ready for processing by the
 ** caller. The values may be accessed using the [column access functions].
 ** sqlite3_step() is called again to retrieve the next row of data.
 **
-** [SQLITE_ERROR] means that a run-time error (such as a constraint
+** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
 ** violation) has occurred.  sqlite3_step() should not be called again on
 ** the VM. More information may be found by calling [sqlite3_errmsg()].
-** With the legacy interface, a more specific error code (for example,
+** ^With the legacy interface, a more specific error code (for example,
 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
 ** can be obtained by calling [sqlite3_reset()] on the
-** [prepared statement].  In the "v2" interface,
+** [prepared statement].  ^In the "v2" interface,
 ** the more specific error code is returned directly by sqlite3_step().
 **
 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
@@ -3628,6 +3475,18 @@ const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 ** be the case that the same database connection is being used by two or
 ** more threads at the same moment in time.
 **
+** For all versions of SQLite up to and including 3.6.23.1, a call to
+** [sqlite3_reset()] was required after sqlite3_step() returned anything
+** other than [SQLITE_ROW] before any subsequent invocation of
+** sqlite3_step().  Failure to reset the prepared statement using 
+** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
+** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
+** calling [sqlite3_reset()] automatically in this circumstance rather
+** than returning [SQLITE_MISUSE].  This is not considered a compatibility
+** break because any application that ever receives an SQLITE_MISUSE error
+** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
+** can be used to restore the legacy behavior.
+**
 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
 ** API always returns a generic error code, [SQLITE_ERROR], following any
 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
@@ -3639,59 +3498,34 @@ const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
 ** then the more specific [error codes] are returned directly
 ** by sqlite3_step().  The use of the "v2" interface is recommended.
-**
-** INVARIANTS:
-**
-** {H13202}  If the [prepared statement] S is ready to be run, then
-**           [sqlite3_step(S)] advances that prepared statement until
-**           completion or until it is ready to return another row of the
-**           result set, or until an [sqlite3_interrupt | interrupt]
-**           or a run-time error occurs.
-**
-** {H15304}  When a call to [sqlite3_step(S)] causes the [prepared statement]
-**           S to run to completion, the function returns [SQLITE_DONE].
-**
-** {H15306}  When a call to [sqlite3_step(S)] stops because it is ready to
-**           return another row of the result set, it returns [SQLITE_ROW].
-**
-** {H15308}  If a call to [sqlite3_step(S)] encounters an
-**           [sqlite3_interrupt | interrupt] or a run-time error,
-**           it returns an appropriate error code that is not one of
-**           [SQLITE_OK], [SQLITE_ROW], or [SQLITE_DONE].
-**
-** {H15310}  If an [sqlite3_interrupt | interrupt] or a run-time error
-**           occurs during a call to [sqlite3_step(S)]
-**           for a [prepared statement] S created using
-**           legacy interfaces [sqlite3_prepare()] or
-**           [sqlite3_prepare16()], then the function returns either
-**           [SQLITE_ERROR], [SQLITE_BUSY], or [SQLITE_MISUSE].
 */
-int sqlite3_step(sqlite3_stmt*);
+SQLITE_API int sqlite3_step(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Number of columns in a result set {H13770} <S10700>
+** CAPI3REF: Number of columns in a result set
 **
-** Returns the number of values in the current row of the result set.
+** ^The sqlite3_data_count(P) interface returns the number of columns in the
+** current row of the result set of [prepared statement] P.
+** ^If prepared statement P does not have results ready to return
+** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
+** interfaces) then sqlite3_data_count(P) returns 0.
+** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
+** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
+** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
+** will return non-zero if previous call to [sqlite3_step](P) returned
+** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
+** where it always returns zero since each step of that multi-step
+** pragma returns 0 columns of data.
 **
-** INVARIANTS:
-**
-** {H13771}  After a call to [sqlite3_step(S)] that returns [SQLITE_ROW],
-**           the [sqlite3_data_count(S)] routine will return the same value
-**           as the [sqlite3_column_count(S)] function.
-**
-** {H13772}  After [sqlite3_step(S)] has returned any value other than
-**           [SQLITE_ROW] or before [sqlite3_step(S)] has been called on the
-**           [prepared statement] for the first time since it was
-**           [sqlite3_prepare | prepared] or [sqlite3_reset | reset],
-**           the [sqlite3_data_count(S)] routine returns zero.
+** See also: [sqlite3_column_count()]
 */
-int sqlite3_data_count(sqlite3_stmt *pStmt);
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120>
+** CAPI3REF: Fundamental Datatypes
 ** KEYWORDS: SQLITE_TEXT
 **
-** {H10266} Every value in SQLite has one of five fundamental datatypes:
+** ^(Every value in SQLite has one of five fundamental datatypes:
 **
 ** <ul>
 ** <li> 64-bit signed integer
@@ -3699,7 +3533,7 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** <li> string
 ** <li> BLOB
 ** <li> NULL
-** </ul> {END}
+** </ul>)^
 **
 ** These constants are codes for each of those types.
 **
@@ -3720,17 +3554,19 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 #define SQLITE3_TEXT     3
 
 /*
-** CAPI3REF: Result Values From A Query {H13800} <S10700>
+** CAPI3REF: Result Values From A Query
 ** KEYWORDS: {column access functions}
 **
-** These routines form the "result set query" interface.
+** These routines form the "result set" interface.
 **
-** These routines return information about a single column of the current
-** result row of a query.  In every case the first argument is a pointer
+** ^These routines return information about a single column of the current
+** result row of a query.  ^In every case the first argument is a pointer
 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
 ** and the second argument is the index of the column for which information
-** should be returned.  The leftmost column of the result set has the index 0.
+** should be returned. ^The leftmost column of the result set has the index 0.
+** ^The number of columns in the result can be determined using
+** [sqlite3_column_count()].
 **
 ** If the SQL statement does not currently point to a valid row, or if the
 ** column index is out of range, the result is undefined.
@@ -3744,9 +3580,9 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** are called from a different thread while any of these routines
 ** are pending, then the results are undefined.
 **
-** The sqlite3_column_type() routine returns the
+** ^The sqlite3_column_type() routine returns the
 ** [SQLITE_INTEGER | datatype code] for the initial data type
-** of the result column.  The returned value is one of [SQLITE_INTEGER],
+** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
 ** returned by sqlite3_column_type() is only meaningful if no type
 ** conversions have occurred as described below.  After a type conversion,
@@ -3754,27 +3590,35 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** versions of SQLite may change the behavior of sqlite3_column_type()
 ** following a type conversion.
 **
-** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
+** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
 ** routine returns the number of bytes in that BLOB or string.
-** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
+** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
 ** the string to UTF-8 and then returns the number of bytes.
-** If the result is a numeric value then sqlite3_column_bytes() uses
+** ^If the result is a numeric value then sqlite3_column_bytes() uses
 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
 ** the number of bytes in that string.
-** The value returned does not include the zero terminator at the end
-** of the string.  For clarity: the value returned is the number of
+** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
+**
+** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
+** the string to UTF-16 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes16() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
+**
+** ^The values returned by [sqlite3_column_bytes()] and 
+** [sqlite3_column_bytes16()] do not include the zero terminators at the end
+** of the string.  ^For clarity: the values returned by
+** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
 ** bytes in the string, not the number of characters.
 **
-** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
-** even empty strings, are always zero terminated.  The return
-** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary
-** pointer, possibly even a NULL pointer.
+** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
+** even empty strings, are always zero-terminated.  ^The return
+** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
 **
-** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
-** but leaves the result in UTF-16 in native byte order instead of UTF-8.
-** The zero terminator is not included in this count.
-**
-** The object returned by [sqlite3_column_value()] is an
+** ^The object returned by [sqlite3_column_value()] is an
 ** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
 ** If the [unprotected sqlite3_value] object returned by
@@ -3782,10 +3626,10 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
 ** or [sqlite3_value_bytes()], then the behavior is undefined.
 **
-** These routines attempt to convert the value where appropriate.  For
+** These routines attempt to convert the value where appropriate.  ^For
 ** example, if the internal representation is FLOAT and a text result
 ** is requested, [sqlite3_snprintf()] is used internally to perform the
-** conversion automatically.  The following table details the conversions
+** conversion automatically.  ^(The following table details the conversions
 ** that are applied:
 **
 ** <blockquote>
@@ -3809,7 +3653,7 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
 ** </table>
-** </blockquote>
+** </blockquote>)^
 **
 ** The table above makes reference to standard C library functions atoi()
 ** and atof().  SQLite does not really use these functions.  It has its
@@ -3835,9 +3679,9 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 **      to UTF-8.</li>
 ** </ul>
 **
-** Conversions between UTF-16be and UTF-16le are always done in place and do
+** ^Conversions between UTF-16be and UTF-16le are always done in place and do
 ** not invalidate a prior pointer, though of course the content of the buffer
-** that the prior pointer points to will have been modified.  Other kinds
+** that the prior pointer references will have been modified.  Other kinds
 ** of conversion are done in place when it is possible, but sometimes they
 ** are not possible and in those cases prior pointers are invalidated.
 **
@@ -3858,282 +3702,172 @@ int sqlite3_data_count(sqlite3_stmt *pStmt);
 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
 ** with calls to sqlite3_column_bytes().
 **
-** The pointers returned are valid until a type conversion occurs as
+** ^The pointers returned are valid until a type conversion occurs as
 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
-** [sqlite3_finalize()] is called.  The memory space used to hold strings
+** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
 ** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
 ** [sqlite3_free()].
 **
-** If a memory allocation error occurs during the evaluation of any
+** ^(If a memory allocation error occurs during the evaluation of any
 ** of these routines, a default value is returned.  The default value
 ** is either the integer 0, the floating point number 0.0, or a NULL
 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
-** [SQLITE_NOMEM].
-**
-** INVARIANTS:
-**
-** {H13803} The [sqlite3_column_blob(S,N)] interface converts the
-**          Nth column in the current row of the result set for
-**          the [prepared statement] S into a BLOB and then returns a
-**          pointer to the converted value.
-**
-** {H13806} The [sqlite3_column_bytes(S,N)] interface returns the
-**          number of bytes in the BLOB or string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_column_blob(S,N)] or
-**          [sqlite3_column_text(S,N)].
-**
-** {H13809} The [sqlite3_column_bytes16(S,N)] interface returns the
-**          number of bytes in the string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_column_text16(S,N)].
-**
-** {H13812} The [sqlite3_column_double(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a floating point value and
-**          returns a copy of that value.
-**
-** {H13815} The [sqlite3_column_int(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a 64-bit signed integer and
-**          returns the lower 32 bits of that integer.
-**
-** {H13818} The [sqlite3_column_int64(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a 64-bit signed integer and
-**          returns a copy of that integer.
-**
-** {H13821} The [sqlite3_column_text(S,N)] interface converts the
-**          Nth column in the current row of the result set for
-**          the [prepared statement] S into a zero-terminated UTF-8
-**          string and returns a pointer to that string.
-**
-** {H13824} The [sqlite3_column_text16(S,N)] interface converts the
-**          Nth column in the current row of the result set for the
-**          [prepared statement] S into a zero-terminated 2-byte
-**          aligned UTF-16 native byte order string and returns
-**          a pointer to that string.
-**
-** {H13827} The [sqlite3_column_type(S,N)] interface returns
-**          one of [SQLITE_NULL], [SQLITE_INTEGER], [SQLITE_FLOAT],
-**          [SQLITE_TEXT], or [SQLITE_BLOB] as appropriate for
-**          the Nth column in the current row of the result set for
-**          the [prepared statement] S.
-**
-** {H13830} The [sqlite3_column_value(S,N)] interface returns a
-**          pointer to an [unprotected sqlite3_value] object for the
-**          Nth column in the current row of the result set for
-**          the [prepared statement] S.
+** [SQLITE_NOMEM].)^
 */
-const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
-int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
-int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
-double sqlite3_column_double(sqlite3_stmt*, int iCol);
-int sqlite3_column_int(sqlite3_stmt*, int iCol);
-sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
-const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
-const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
-int sqlite3_column_type(sqlite3_stmt*, int iCol);
-sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
+SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
 
 /*
-** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100>
+** CAPI3REF: Destroy A Prepared Statement Object
 **
-** The sqlite3_finalize() function is called to delete a [prepared statement].
-** If the statement was executed successfully or not executed at all, then
-** SQLITE_OK is returned. If execution of the statement failed then an
-** [error code] or [extended error code] is returned.
+** ^The sqlite3_finalize() function is called to delete a [prepared statement].
+** ^If the most recent evaluation of the statement encountered no errors
+** or if the statement is never been evaluated, then sqlite3_finalize() returns
+** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
+** sqlite3_finalize(S) returns the appropriate [error code] or
+** [extended error code].
 **
-** This routine can be called at any point during the execution of the
-** [prepared statement].  If the virtual machine has not
-** completed execution when this routine is called, that is like
-** encountering an error or an [sqlite3_interrupt | interrupt].
-** Incomplete updates may be rolled back and transactions canceled,
-** depending on the circumstances, and the
-** [error code] returned will be [SQLITE_ABORT].
+** ^The sqlite3_finalize(S) routine can be called at any point during
+** the life cycle of [prepared statement] S:
+** before statement S is ever evaluated, after
+** one or more calls to [sqlite3_reset()], or after any call
+** to [sqlite3_step()] regardless of whether or not the statement has
+** completed execution.
 **
-** INVARIANTS:
+** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
 **
-** {H11302} The [sqlite3_finalize(S)] interface destroys the
-**          [prepared statement] S and releases all
-**          memory and file resources held by that object.
-**
-** {H11304} If the most recent call to [sqlite3_step(S)] for the
-**          [prepared statement] S returned an error,
-**          then [sqlite3_finalize(S)] returns that same error.
+** The application must finalize every [prepared statement] in order to avoid
+** resource leaks.  It is a grievous error for the application to try to use
+** a prepared statement after it has been finalized.  Any use of a prepared
+** statement after it has been finalized can result in undefined and
+** undesirable behavior such as segfaults and heap corruption.
 */
-int sqlite3_finalize(sqlite3_stmt *pStmt);
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300>
+** CAPI3REF: Reset A Prepared Statement Object
 **
 ** The sqlite3_reset() function is called to reset a [prepared statement]
 ** object back to its initial state, ready to be re-executed.
-** Any SQL statement variables that had values bound to them using
+** ^Any SQL statement variables that had values bound to them using
 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
 ** Use [sqlite3_clear_bindings()] to reset the bindings.
 **
-** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S
-**          back to the beginning of its program.
+** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
+** back to the beginning of its program.
 **
-** {H11334} If the most recent call to [sqlite3_step(S)] for the
-**          [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
-**          or if [sqlite3_step(S)] has never before been called on S,
-**          then [sqlite3_reset(S)] returns [SQLITE_OK].
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
+** or if [sqlite3_step(S)] has never before been called on S,
+** then [sqlite3_reset(S)] returns [SQLITE_OK].
 **
-** {H11336} If the most recent call to [sqlite3_step(S)] for the
-**          [prepared statement] S indicated an error, then
-**          [sqlite3_reset(S)] returns an appropriate [error code].
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S indicated an error, then
+** [sqlite3_reset(S)] returns an appropriate [error code].
 **
-** {H11338} The [sqlite3_reset(S)] interface does not change the values
-**          of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
+** ^The [sqlite3_reset(S)] interface does not change the values
+** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
 */
-int sqlite3_reset(sqlite3_stmt *pStmt);
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200>
+** CAPI3REF: Create Or Redefine SQL Functions
 ** KEYWORDS: {function creation routines}
 ** KEYWORDS: {application-defined SQL function}
 ** KEYWORDS: {application-defined SQL functions}
 **
-** These two functions (collectively known as "function creation routines")
+** ^These functions (collectively known as "function creation routines")
 ** are used to add SQL functions or aggregates or to redefine the behavior
-** of existing SQL functions or aggregates.  The only difference between the
-** two is that the second parameter, the name of the (scalar) function or
-** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16
-** for sqlite3_create_function16().
+** of existing SQL functions or aggregates.  The only differences between
+** these routines are the text encoding expected for
+** the second parameter (the name of the function being created)
+** and the presence or absence of a destructor callback for
+** the application data pointer.
 **
-** The first parameter is the [database connection] to which the SQL
-** function is to be added.  If a single program uses more than one database
-** connection internally, then SQL functions must be added individually to
-** each database connection.
+** ^The first parameter is the [database connection] to which the SQL
+** function is to be added.  ^If an application uses more than one database
+** connection then application-defined SQL functions must be added
+** to each database connection separately.
 **
-** The second parameter is the name of the SQL function to be created or
-** redefined.  The length of the name is limited to 255 bytes, exclusive of
-** the zero-terminator.  Note that the name length limit is in bytes, not
-** characters.  Any attempt to create a function with a longer name
-** will result in [SQLITE_ERROR] being returned.
+** ^The second parameter is the name of the SQL function to be created or
+** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
+** representation, exclusive of the zero-terminator.  ^Note that the name
+** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.  
+** ^Any attempt to create a function with a longer name
+** will result in [SQLITE_MISUSE] being returned.
 **
-** The third parameter (nArg)
+** ^The third parameter (nArg)
 ** is the number of arguments that the SQL function or
-** aggregate takes. If this parameter is negative, then the SQL function or
-** aggregate may take any number of arguments.
+** aggregate takes. ^If this parameter is -1, then the SQL function or
+** aggregate may take any number of arguments between 0 and the limit
+** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
+** parameter is less than -1 or greater than 127 then the behavior is
+** undefined.
 **
-** The fourth parameter, eTextRep, specifies what
+** ^The fourth parameter, eTextRep, specifies what
 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
-** its parameters.  Any SQL function implementation should be able to work
-** work with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
-** more efficient with one encoding than another.  It is allowed to
+** its parameters.  Every SQL function implementation must be able to work
+** with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
+** more efficient with one encoding than another.  ^An application may
 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
 ** times with the same function but with different values of eTextRep.
-** When multiple implementations of the same function are available, SQLite
+** ^When multiple implementations of the same function are available, SQLite
 ** will pick the one that involves the least amount of data conversion.
 ** If there is only a single implementation which does not care what text
 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
 **
-** The fifth parameter is an arbitrary pointer.  The implementation of the
-** function can gain access to this pointer using [sqlite3_user_data()].
+** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
+** function can gain access to this pointer using [sqlite3_user_data()].)^
 **
-** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
+** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
 ** pointers to C-language functions that implement the SQL function or
-** aggregate. A scalar SQL function requires an implementation of the xFunc
-** callback only, NULL pointers should be passed as the xStep and xFinal
-** parameters. An aggregate SQL function requires an implementation of xStep
-** and xFinal and NULL should be passed for xFunc. To delete an existing
-** SQL function or aggregate, pass NULL for all three function callbacks.
+** aggregate. ^A scalar SQL function requires an implementation of the xFunc
+** callback only; NULL pointers must be passed as the xStep and xFinal
+** parameters. ^An aggregate SQL function requires an implementation of xStep
+** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
+** SQL function or aggregate, pass NULL pointers for all three function
+** callbacks.
 **
-** It is permitted to register multiple implementations of the same
+** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
+** then it is destructor for the application data pointer. 
+** The destructor is invoked when the function is deleted, either by being
+** overloaded or when the database connection closes.)^
+** ^The destructor is also invoked if the call to
+** sqlite3_create_function_v2() fails.
+** ^When the destructor callback of the tenth parameter is invoked, it
+** is passed a single argument which is a copy of the application data 
+** pointer which was the fifth parameter to sqlite3_create_function_v2().
+**
+** ^It is permitted to register multiple implementations of the same
 ** functions with the same name but with either differing numbers of
-** arguments or differing preferred text encodings.  SQLite will use
-** the implementation most closely matches the way in which the
-** SQL function is used.  A function implementation with a non-negative
+** arguments or differing preferred text encodings.  ^SQLite will use
+** the implementation that most closely matches the way in which the
+** SQL function is used.  ^A function implementation with a non-negative
 ** nArg parameter is a better match than a function implementation with
-** a negative nArg.  A function where the preferred text encoding
+** a negative nArg.  ^A function where the preferred text encoding
 ** matches the database encoding is a better
 ** match than a function where the encoding is different.  
-** A function where the encoding difference is between UTF16le and UTF16be
+** ^A function where the encoding difference is between UTF16le and UTF16be
 ** is a closer match than a function where the encoding difference is
 ** between UTF8 and UTF16.
 **
-** Built-in functions may be overloaded by new application-defined functions.
-** The first application-defined function with a given name overrides all
-** built-in functions in the same [database connection] with the same name.
-** Subsequent application-defined functions of the same name only override 
-** prior application-defined functions that are an exact match for the
-** number of parameters and preferred encoding.
+** ^Built-in functions may be overloaded by new application-defined functions.
 **
-** An application-defined function is permitted to call other
+** ^An application-defined function is permitted to call other
 ** SQLite interfaces.  However, such calls must not
 ** close the database connection nor finalize or reset the prepared
 ** statement in which the function is running.
-**
-** INVARIANTS:
-**
-** {H16103} The [sqlite3_create_function16(D,X,...)] interface shall behave
-**          as [sqlite3_create_function(D,X,...)] in every way except that it
-**          interprets the X argument as zero-terminated UTF-16
-**          native byte order instead of as zero-terminated UTF-8.
-**
-** {H16106} A successful invocation of the
-**          [sqlite3_create_function(D,X,N,E,...)] interface shall register
-**          or replaces callback functions in the [database connection] D
-**          used to implement the SQL function named X with N parameters
-**          and having a preferred text encoding of E.
-**
-** {H16109} A successful call to [sqlite3_create_function(D,X,N,E,P,F,S,L)]
-**          shall replace the P, F, S, and L values from any prior calls with
-**          the same D, X, N, and E values.
-**
-** {H16112} The [sqlite3_create_function(D,X,...)] interface shall fail
-**          if the SQL function name X is
-**          longer than 255 bytes exclusive of the zero terminator.
-**
-** {H16118} The [sqlite3_create_function(D,X,N,E,P,F,S,L)] interface
-**          shall fail unless either F is NULL and S and L are non-NULL or
-***         F is non-NULL and S and L are NULL.
-**
-** {H16121} The [sqlite3_create_function(D,...)] interface shall fails with an
-**          error code of [SQLITE_BUSY] if there exist [prepared statements]
-**          associated with the [database connection] D.
-**
-** {H16124} The [sqlite3_create_function(D,X,N,...)] interface shall fail with
-**          an error code of [SQLITE_ERROR] if parameter N is less
-**          than -1 or greater than 127.
-**
-** {H16127} When N is non-negative, the [sqlite3_create_function(D,X,N,...)]
-**          interface shall register callbacks to be invoked for the
-**          SQL function
-**          named X when the number of arguments to the SQL function is
-**          exactly N.
-**
-** {H16130} When N is -1, the [sqlite3_create_function(D,X,N,...)]
-**          interface shall register callbacks to be invoked for the SQL
-**          function named X with any number of arguments.
-**
-** {H16133} When calls to [sqlite3_create_function(D,X,N,...)]
-**          specify multiple implementations of the same function X
-**          and when one implementation has N>=0 and the other has N=(-1)
-**          the implementation with a non-zero N shall be preferred.
-**
-** {H16136} When calls to [sqlite3_create_function(D,X,N,E,...)]
-**          specify multiple implementations of the same function X with
-**          the same number of arguments N but with different
-**          encodings E, then the implementation where E matches the
-**          database encoding shall preferred.
-**
-** {H16139} For an aggregate SQL function created using
-**          [sqlite3_create_function(D,X,N,E,P,0,S,L)] the finalizer
-**          function L shall always be invoked exactly once if the
-**          step function S is called one or more times.
-**
-** {H16142} When SQLite invokes either the xFunc or xStep function of
-**          an application-defined SQL function or aggregate created
-**          by [sqlite3_create_function()] or [sqlite3_create_function16()],
-**          then the array of [sqlite3_value] objects passed as the
-**          third parameter shall be [protected sqlite3_value] objects.
 */
-int sqlite3_create_function(
+SQLITE_API int sqlite3_create_function(
   sqlite3 *db,
   const char *zFunctionName,
   int nArg,
@@ -4143,7 +3877,7 @@ int sqlite3_create_function(
   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
   void (*xFinal)(sqlite3_context*)
 );
-int sqlite3_create_function16(
+SQLITE_API int sqlite3_create_function16(
   sqlite3 *db,
   const void *zFunctionName,
   int nArg,
@@ -4153,9 +3887,20 @@ int sqlite3_create_function16(
   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
   void (*xFinal)(sqlite3_context*)
 );
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void(*xDestroy)(void*)
+);
 
 /*
-** CAPI3REF: Text Encodings {H10267} <S50200> <H16100>
+** CAPI3REF: Text Encodings
 **
 ** These constant define integer codes that represent the various
 ** text encodings supported by SQLite.
@@ -4178,16 +3923,16 @@ int sqlite3_create_function16(
 ** using these functions, we are not going to tell you what they do.
 */
 #ifndef SQLITE_OMIT_DEPRECATED
-SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
-SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
-SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
-SQLITE_DEPRECATED int sqlite3_global_recover(void);
-SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
-SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
+SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
 #endif
 
 /*
-** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200>
+** CAPI3REF: Obtaining SQL Function Parameter Values
 **
 ** The C-language implementation of SQL functions and aggregates uses
 ** this set of interface routines to access the parameter values on
@@ -4196,7 +3941,7 @@ SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void
 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
 ** define callbacks that implement the SQL functions and aggregates.
-** The 4th parameter to these callbacks is an array of pointers to
+** The 3rd parameter to these callbacks is an array of pointers to
 ** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
 ** each parameter to the SQL function.  These routines are used to
 ** extract values from the [sqlite3_value] objects.
@@ -4205,22 +3950,22 @@ SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void
 ** Any attempt to use these routines on an [unprotected sqlite3_value]
 ** object results in undefined behavior.
 **
-** These routines work just like the corresponding [column access functions]
+** ^These routines work just like the corresponding [column access functions]
 ** except that  these routines take a single [protected sqlite3_value] object
 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
 **
-** The sqlite3_value_text16() interface extracts a UTF-16 string
-** in the native byte-order of the host machine.  The
+** ^The sqlite3_value_text16() interface extracts a UTF-16 string
+** in the native byte-order of the host machine.  ^The
 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
 ** extract UTF-16 strings as big-endian and little-endian respectively.
 **
-** The sqlite3_value_numeric_type() interface attempts to apply
+** ^(The sqlite3_value_numeric_type() interface attempts to apply
 ** numeric affinity to the value.  This means that an attempt is
 ** made to convert the value to an integer or floating point.  If
 ** such a conversion is possible without loss of information (in other
 ** words, if the value is a string that looks like a number)
 ** then the conversion is performed.  Otherwise no conversion occurs.
-** The [SQLITE_INTEGER | datatype] after conversion is returned.
+** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
 **
 ** Please pay particular attention to the fact that the pointer returned
 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
@@ -4230,168 +3975,88 @@ SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void
 **
 ** These routines must be called from the same thread as
 ** the SQL function that supplied the [sqlite3_value*] parameters.
-**
-** INVARIANTS:
-**
-** {H15103} The [sqlite3_value_blob(V)] interface converts the
-**          [protected sqlite3_value] object V into a BLOB and then
-**          returns a pointer to the converted value.
-**
-** {H15106} The [sqlite3_value_bytes(V)] interface returns the
-**          number of bytes in the BLOB or string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_value_blob(V)] or
-**          [sqlite3_value_text(V)].
-**
-** {H15109} The [sqlite3_value_bytes16(V)] interface returns the
-**          number of bytes in the string (exclusive of the
-**          zero terminator on the string) that was returned by the
-**          most recent call to [sqlite3_value_text16(V)],
-**          [sqlite3_value_text16be(V)], or [sqlite3_value_text16le(V)].
-**
-** {H15112} The [sqlite3_value_double(V)] interface converts the
-**          [protected sqlite3_value] object V into a floating point value and
-**          returns a copy of that value.
-**
-** {H15115} The [sqlite3_value_int(V)] interface converts the
-**          [protected sqlite3_value] object V into a 64-bit signed integer and
-**          returns the lower 32 bits of that integer.
-**
-** {H15118} The [sqlite3_value_int64(V)] interface converts the
-**          [protected sqlite3_value] object V into a 64-bit signed integer and
-**          returns a copy of that integer.
-**
-** {H15121} The [sqlite3_value_text(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated UTF-8
-**          string and returns a pointer to that string.
-**
-** {H15124} The [sqlite3_value_text16(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated 2-byte
-**          aligned UTF-16 native byte order
-**          string and returns a pointer to that string.
-**
-** {H15127} The [sqlite3_value_text16be(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated 2-byte
-**          aligned UTF-16 big-endian
-**          string and returns a pointer to that string.
-**
-** {H15130} The [sqlite3_value_text16le(V)] interface converts the
-**          [protected sqlite3_value] object V into a zero-terminated 2-byte
-**          aligned UTF-16 little-endian
-**          string and returns a pointer to that string.
-**
-** {H15133} The [sqlite3_value_type(V)] interface returns
-**          one of [SQLITE_NULL], [SQLITE_INTEGER], [SQLITE_FLOAT],
-**          [SQLITE_TEXT], or [SQLITE_BLOB] as appropriate for
-**          the [sqlite3_value] object V.
-**
-** {H15136} The [sqlite3_value_numeric_type(V)] interface converts
-**          the [protected sqlite3_value] object V into either an integer or
-**          a floating point value if it can do so without loss of
-**          information, and returns one of [SQLITE_NULL],
-**          [SQLITE_INTEGER], [SQLITE_FLOAT], [SQLITE_TEXT], or
-**          [SQLITE_BLOB] as appropriate for the
-**          [protected sqlite3_value] object V after the conversion attempt.
 */
-const void *sqlite3_value_blob(sqlite3_value*);
-int sqlite3_value_bytes(sqlite3_value*);
-int sqlite3_value_bytes16(sqlite3_value*);
-double sqlite3_value_double(sqlite3_value*);
-int sqlite3_value_int(sqlite3_value*);
-sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
-const unsigned char *sqlite3_value_text(sqlite3_value*);
-const void *sqlite3_value_text16(sqlite3_value*);
-const void *sqlite3_value_text16le(sqlite3_value*);
-const void *sqlite3_value_text16be(sqlite3_value*);
-int sqlite3_value_type(sqlite3_value*);
-int sqlite3_value_numeric_type(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
+SQLITE_API double sqlite3_value_double(sqlite3_value*);
+SQLITE_API int sqlite3_value_int(sqlite3_value*);
+SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
+SQLITE_API int sqlite3_value_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
 
 /*
-** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200>
+** CAPI3REF: Obtain Aggregate Function Context
 **
-** The implementation of aggregate SQL functions use this routine to allocate
-** a structure for storing their state.
+** Implementations of aggregate SQL functions use this
+** routine to allocate memory for storing their state.
 **
-** The first time the sqlite3_aggregate_context() routine is called for a
-** particular aggregate, SQLite allocates nBytes of memory, zeroes out that
-** memory, and returns a pointer to it. On second and subsequent calls to
-** sqlite3_aggregate_context() for the same aggregate function index,
-** the same buffer is returned. The implementation of the aggregate can use
-** the returned buffer to accumulate data.
+** ^The first time the sqlite3_aggregate_context(C,N) routine is called 
+** for a particular aggregate function, SQLite
+** allocates N of memory, zeroes out that memory, and returns a pointer
+** to the new memory. ^On second and subsequent calls to
+** sqlite3_aggregate_context() for the same aggregate function instance,
+** the same buffer is returned.  Sqlite3_aggregate_context() is normally
+** called once for each invocation of the xStep callback and then one
+** last time when the xFinal callback is invoked.  ^(When no rows match
+** an aggregate query, the xStep() callback of the aggregate function
+** implementation is never called and xFinal() is called exactly once.
+** In those cases, sqlite3_aggregate_context() might be called for the
+** first time from within xFinal().)^
 **
-** SQLite automatically frees the allocated buffer when the aggregate
-** query concludes.
+** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
+** less than or equal to zero or if a memory allocate error occurs.
 **
-** The first parameter should be a copy of the
+** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
+** determined by the N parameter on first successful call.  Changing the
+** value of N in subsequent call to sqlite3_aggregate_context() within
+** the same aggregate function instance will not resize the memory
+** allocation.)^
+**
+** ^SQLite automatically frees the memory allocated by 
+** sqlite3_aggregate_context() when the aggregate query concludes.
+**
+** The first parameter must be a copy of the
 ** [sqlite3_context | SQL function context] that is the first parameter
-** to the callback routine that implements the aggregate function.
+** to the xStep or xFinal callback routine that implements the aggregate
+** function.
 **
 ** This routine must be called from the same thread in which
 ** the aggregate SQL function is running.
-**
-** INVARIANTS:
-**
-** {H16211} The first invocation of [sqlite3_aggregate_context(C,N)] for
-**          a particular instance of an aggregate function (for a particular
-**          context C) causes SQLite to allocate N bytes of memory,
-**          zero that memory, and return a pointer to the allocated memory.
-**
-** {H16213} If a memory allocation error occurs during
-**          [sqlite3_aggregate_context(C,N)] then the function returns 0.
-**
-** {H16215} Second and subsequent invocations of
-**          [sqlite3_aggregate_context(C,N)] for the same context pointer C
-**          ignore the N parameter and return a pointer to the same
-**          block of memory returned by the first invocation.
-**
-** {H16217} The memory allocated by [sqlite3_aggregate_context(C,N)] is
-**          automatically freed on the next call to [sqlite3_reset()]
-**          or [sqlite3_finalize()] for the [prepared statement] containing
-**          the aggregate function associated with context C.
 */
-void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
 
 /*
-** CAPI3REF: User Data For Functions {H16240} <S20200>
+** CAPI3REF: User Data For Functions
 **
-** The sqlite3_user_data() interface returns a copy of
+** ^The sqlite3_user_data() interface returns a copy of
 ** the pointer that was the pUserData parameter (the 5th parameter)
 ** of the [sqlite3_create_function()]
 ** and [sqlite3_create_function16()] routines that originally
-** registered the application defined function. {END}
-**
-** This routine must be called from the same thread in which
-** the application-defined function is running.
-**
-** INVARIANTS:
-**
-** {H16243} The [sqlite3_user_data(C)] interface returns a copy of the
-**          P pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]
-**          or [sqlite3_create_function16(D,X,N,E,P,F,S,L)] call that
-**          registered the SQL function associated with [sqlite3_context] C.
-*/
-void *sqlite3_user_data(sqlite3_context*);
-
-/*
-** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200>
-**
-** The sqlite3_context_db_handle() interface returns a copy of
-** the pointer to the [database connection] (the 1st parameter)
-** of the [sqlite3_create_function()]
-** and [sqlite3_create_function16()] routines that originally
 ** registered the application defined function.
 **
-** INVARIANTS:
-**
-** {H16253} The [sqlite3_context_db_handle(C)] interface returns a copy of the
-**          D pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]
-**          or [sqlite3_create_function16(D,X,N,E,P,F,S,L)] call that
-**          registered the SQL function associated with [sqlite3_context] C.
+** This routine must be called from the same thread in which
+** the application-defined function is running.
 */
-sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
+SQLITE_API void *sqlite3_user_data(sqlite3_context*);
 
 /*
-** CAPI3REF: Function Auxiliary Data {H16270} <S20200>
+** CAPI3REF: Database Connection For Functions
+**
+** ^The sqlite3_context_db_handle() interface returns a copy of
+** the pointer to the [database connection] (the 1st parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
+
+/*
+** CAPI3REF: Function Auxiliary Data
 **
 ** The following two functions may be used by scalar SQL functions to
 ** associate metadata with argument values. If the same value is passed to
@@ -4404,71 +4069,45 @@ sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
 ** invocations of the same function so that the original pattern string
 ** does not need to be recompiled on each invocation.
 **
-** The sqlite3_get_auxdata() interface returns a pointer to the metadata
+** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
 ** associated by the sqlite3_set_auxdata() function with the Nth argument
-** value to the application-defined function. If no metadata has been ever
+** value to the application-defined function. ^If no metadata has been ever
 ** been set for the Nth argument of the function, or if the corresponding
 ** function parameter has changed since the meta-data was set,
 ** then sqlite3_get_auxdata() returns a NULL pointer.
 **
-** The sqlite3_set_auxdata() interface saves the metadata
+** ^The sqlite3_set_auxdata() interface saves the metadata
 ** pointed to by its 3rd parameter as the metadata for the N-th
 ** argument of the application-defined function.  Subsequent
 ** calls to sqlite3_get_auxdata() might return this data, if it has
 ** not been destroyed.
-** If it is not NULL, SQLite will invoke the destructor
+** ^If it is not NULL, SQLite will invoke the destructor
 ** function given by the 4th parameter to sqlite3_set_auxdata() on
 ** the metadata when the corresponding function parameter changes
 ** or when the SQL statement completes, whichever comes first.
 **
 ** SQLite is free to call the destructor and drop metadata on any
-** parameter of any function at any time.  The only guarantee is that
+** parameter of any function at any time.  ^The only guarantee is that
 ** the destructor will be called before the metadata is dropped.
 **
-** In practice, metadata is preserved between function calls for
+** ^(In practice, metadata is preserved between function calls for
 ** expressions that are constant at compile time. This includes literal
-** values and SQL variables.
+** values and [parameters].)^
 **
 ** These routines must be called from the same thread in which
 ** the SQL function is running.
-**
-** INVARIANTS:
-**
-** {H16272} The [sqlite3_get_auxdata(C,N)] interface returns a pointer
-**          to metadata associated with the Nth parameter of the SQL function
-**          whose context is C, or NULL if there is no metadata associated
-**          with that parameter.
-**
-** {H16274} The [sqlite3_set_auxdata(C,N,P,D)] interface assigns a metadata
-**          pointer P to the Nth parameter of the SQL function with context C.
-**
-** {H16276} SQLite will invoke the destructor D with a single argument
-**          which is the metadata pointer P following a call to
-**          [sqlite3_set_auxdata(C,N,P,D)] when SQLite ceases to hold
-**          the metadata.
-**
-** {H16277} SQLite ceases to hold metadata for an SQL function parameter
-**          when the value of that parameter changes.
-**
-** {H16278} When [sqlite3_set_auxdata(C,N,P,D)] is invoked, the destructor
-**          is called for any prior metadata associated with the same function
-**          context C and parameter N.
-**
-** {H16279} SQLite will call destructors for any metadata it is holding
-**          in a particular [prepared statement] S when either
-**          [sqlite3_reset(S)] or [sqlite3_finalize(S)] is called.
 */
-void *sqlite3_get_auxdata(sqlite3_context*, int N);
-void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
+SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
 
 
 /*
-** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100>
+** CAPI3REF: Constants Defining Special Destructor Behavior
 **
 ** These are special values for the destructor that is passed in as the
-** final argument to routines like [sqlite3_result_blob()].  If the destructor
+** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
 ** argument is SQLITE_STATIC, it means that the content pointer is constant
-** and will never change.  It does not need to be destroyed.  The
+** and will never change.  It does not need to be destroyed.  ^The
 ** SQLITE_TRANSIENT value means that the content will likely change in
 ** the near future and that SQLite should make its own private copy of
 ** the content before returning.
@@ -4481,7 +4120,7 @@ typedef void (*sqlite3_destructor_type)(void*);
 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
 
 /*
-** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200>
+** CAPI3REF: Setting The Result Of An SQL Function
 **
 ** These routines are used by the xFunc or xFinal callbacks that
 ** implement SQL functions and aggregates.  See
@@ -4492,381 +4131,261 @@ typedef void (*sqlite3_destructor_type)(void*);
 ** functions used to bind values to host parameters in prepared statements.
 ** Refer to the [SQL parameter] documentation for additional information.
 **
-** The sqlite3_result_blob() interface sets the result from
+** ^The sqlite3_result_blob() interface sets the result from
 ** an application-defined function to be the BLOB whose content is pointed
 ** to by the second parameter and which is N bytes long where N is the
 ** third parameter.
 **
-** The sqlite3_result_zeroblob() interfaces set the result of
+** ^The sqlite3_result_zeroblob() interfaces set the result of
 ** the application-defined function to be a BLOB containing all zero
 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
 **
-** The sqlite3_result_double() interface sets the result from
+** ^The sqlite3_result_double() interface sets the result from
 ** an application-defined function to be a floating point value specified
 ** by its 2nd argument.
 **
-** The sqlite3_result_error() and sqlite3_result_error16() functions
+** ^The sqlite3_result_error() and sqlite3_result_error16() functions
 ** cause the implemented SQL function to throw an exception.
-** SQLite uses the string pointed to by the
+** ^SQLite uses the string pointed to by the
 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
-** as the text of an error message.  SQLite interprets the error
-** message string from sqlite3_result_error() as UTF-8. SQLite
+** as the text of an error message.  ^SQLite interprets the error
+** message string from sqlite3_result_error() as UTF-8. ^SQLite
 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
-** byte order.  If the third parameter to sqlite3_result_error()
+** byte order.  ^If the third parameter to sqlite3_result_error()
 ** or sqlite3_result_error16() is negative then SQLite takes as the error
 ** message all text up through the first zero character.
-** If the third parameter to sqlite3_result_error() or
+** ^If the third parameter to sqlite3_result_error() or
 ** sqlite3_result_error16() is non-negative then SQLite takes that many
 ** bytes (not characters) from the 2nd parameter as the error message.
-** The sqlite3_result_error() and sqlite3_result_error16()
+** ^The sqlite3_result_error() and sqlite3_result_error16()
 ** routines make a private copy of the error message text before
 ** they return.  Hence, the calling function can deallocate or
 ** modify the text after they return without harm.
-** The sqlite3_result_error_code() function changes the error code
-** returned by SQLite as a result of an error in a function.  By default,
-** the error code is SQLITE_ERROR.  A subsequent call to sqlite3_result_error()
+** ^The sqlite3_result_error_code() function changes the error code
+** returned by SQLite as a result of an error in a function.  ^By default,
+** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
 **
-** The sqlite3_result_toobig() interface causes SQLite to throw an error
-** indicating that a string or BLOB is to long to represent.
+** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
+** error indicating that a string or BLOB is too long to represent.
 **
-** The sqlite3_result_nomem() interface causes SQLite to throw an error
-** indicating that a memory allocation failed.
+** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
+** error indicating that a memory allocation failed.
 **
-** The sqlite3_result_int() interface sets the return value
+** ^The sqlite3_result_int() interface sets the return value
 ** of the application-defined function to be the 32-bit signed integer
 ** value given in the 2nd argument.
-** The sqlite3_result_int64() interface sets the return value
+** ^The sqlite3_result_int64() interface sets the return value
 ** of the application-defined function to be the 64-bit signed integer
 ** value given in the 2nd argument.
 **
-** The sqlite3_result_null() interface sets the return value
+** ^The sqlite3_result_null() interface sets the return value
 ** of the application-defined function to be NULL.
 **
-** The sqlite3_result_text(), sqlite3_result_text16(),
+** ^The sqlite3_result_text(), sqlite3_result_text16(),
 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
 ** set the return value of the application-defined function to be
 ** a text string which is represented as UTF-8, UTF-16 native byte order,
 ** UTF-16 little endian, or UTF-16 big endian, respectively.
-** SQLite takes the text result from the application from
+** ^SQLite takes the text result from the application from
 ** the 2nd parameter of the sqlite3_result_text* interfaces.
-** If the 3rd parameter to the sqlite3_result_text* interfaces
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 ** is negative, then SQLite takes result text from the 2nd parameter
 ** through the first zero character.
-** If the 3rd parameter to the sqlite3_result_text* interfaces
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 ** is non-negative, then as many bytes (not characters) of the text
 ** pointed to by the 2nd parameter are taken as the application-defined
-** function result.
-** If the 4th parameter to the sqlite3_result_text* interfaces
+** function result.  If the 3rd parameter is non-negative, then it
+** must be the byte offset into the string where the NUL terminator would
+** appear if the string where NUL terminated.  If any NUL characters occur
+** in the string at a byte offset that is less than the value of the 3rd
+** parameter, then the resulting string will contain embedded NULs and the
+** result of expressions operating on strings with embedded NULs is undefined.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
 ** function as the destructor on the text or BLOB result when it has
 ** finished using that result.
-** If the 4th parameter to the sqlite3_result_text* interfaces or
+** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
 ** assumes that the text or BLOB result is in constant space and does not
-** copy the it or call a destructor when it has finished using that result.
-** If the 4th parameter to the sqlite3_result_text* interfaces
+** copy the content of the parameter nor call a destructor on the content
+** when it has finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
 ** then SQLite makes a copy of the result into space obtained from
 ** from [sqlite3_malloc()] before it returns.
 **
-** The sqlite3_result_value() interface sets the result of
+** ^The sqlite3_result_value() interface sets the result of
 ** the application-defined function to be a copy the
-** [unprotected sqlite3_value] object specified by the 2nd parameter.  The
+** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
 ** so that the [sqlite3_value] specified in the parameter may change or
 ** be deallocated after sqlite3_result_value() returns without harm.
-** A [protected sqlite3_value] object may always be used where an
+** ^A [protected sqlite3_value] object may always be used where an
 ** [unprotected sqlite3_value] object is required, so either
 ** kind of [sqlite3_value] object can be used with this interface.
 **
 ** If these routines are called from within the different thread
 ** than the one containing the application-defined function that received
 ** the [sqlite3_context] pointer, the results are undefined.
-**
-** INVARIANTS:
-**
-** {H16403} The default return value from any SQL function is NULL.
-**
-** {H16406} The [sqlite3_result_blob(C,V,N,D)] interface changes the
-**          return value of function C to be a BLOB that is N bytes
-**          in length and with content pointed to by V.
-**
-** {H16409} The [sqlite3_result_double(C,V)] interface changes the
-**          return value of function C to be the floating point value V.
-**
-** {H16412} The [sqlite3_result_error(C,V,N)] interface changes the return
-**          value of function C to be an exception with error code
-**          [SQLITE_ERROR] and a UTF-8 error message copied from V up to the
-**          first zero byte or until N bytes are read if N is positive.
-**
-** {H16415} The [sqlite3_result_error16(C,V,N)] interface changes the return
-**          value of function C to be an exception with error code
-**          [SQLITE_ERROR] and a UTF-16 native byte order error message
-**          copied from V up to the first zero terminator or until N bytes
-**          are read if N is positive.
-**
-** {H16418} The [sqlite3_result_error_toobig(C)] interface changes the return
-**          value of the function C to be an exception with error code
-**          [SQLITE_TOOBIG] and an appropriate error message.
-**
-** {H16421} The [sqlite3_result_error_nomem(C)] interface changes the return
-**          value of the function C to be an exception with error code
-**          [SQLITE_NOMEM] and an appropriate error message.
-**
-** {H16424} The [sqlite3_result_error_code(C,E)] interface changes the return
-**          value of the function C to be an exception with error code E.
-**          The error message text is unchanged.
-**
-** {H16427} The [sqlite3_result_int(C,V)] interface changes the
-**          return value of function C to be the 32-bit integer value V.
-**
-** {H16430} The [sqlite3_result_int64(C,V)] interface changes the
-**          return value of function C to be the 64-bit integer value V.
-**
-** {H16433} The [sqlite3_result_null(C)] interface changes the
-**          return value of function C to be NULL.
-**
-** {H16436} The [sqlite3_result_text(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-8 string
-**          V up to the first zero if N is negative
-**          or the first N bytes of V if N is non-negative.
-**
-** {H16439} The [sqlite3_result_text16(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-16 native byte order
-**          string V up to the first zero if N is negative
-**          or the first N bytes of V if N is non-negative.
-**
-** {H16442} The [sqlite3_result_text16be(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-16 big-endian
-**          string V up to the first zero if N is negative
-**          or the first N bytes or V if N is non-negative.
-**
-** {H16445} The [sqlite3_result_text16le(C,V,N,D)] interface changes the
-**          return value of function C to be the UTF-16 little-endian
-**          string V up to the first zero if N is negative
-**          or the first N bytes of V if N is non-negative.
-**
-** {H16448} The [sqlite3_result_value(C,V)] interface changes the
-**          return value of function C to be the [unprotected sqlite3_value]
-**          object V.
-**
-** {H16451} The [sqlite3_result_zeroblob(C,N)] interface changes the
-**          return value of function C to be an N-byte BLOB of all zeros.
-**
-** {H16454} The [sqlite3_result_error()] and [sqlite3_result_error16()]
-**          interfaces make a copy of their error message strings before
-**          returning.
-**
-** {H16457} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
-**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
-**          [sqlite3_result_text16be(C,V,N,D)], or
-**          [sqlite3_result_text16le(C,V,N,D)] is the constant [SQLITE_STATIC]
-**          then no destructor is ever called on the pointer V and SQLite
-**          assumes that V is immutable.
-**
-** {H16460} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
-**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
-**          [sqlite3_result_text16be(C,V,N,D)], or
-**          [sqlite3_result_text16le(C,V,N,D)] is the constant
-**          [SQLITE_TRANSIENT] then the interfaces makes a copy of the
-**          content of V and retains the copy.
-**
-** {H16463} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
-**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
-**          [sqlite3_result_text16be(C,V,N,D)], or
-**          [sqlite3_result_text16le(C,V,N,D)] is some value other than
-**          the constants [SQLITE_STATIC] and [SQLITE_TRANSIENT] then
-**          SQLite will invoke the destructor D with V as its only argument
-**          when it has finished with the V value.
 */
-void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
-void sqlite3_result_double(sqlite3_context*, double);
-void sqlite3_result_error(sqlite3_context*, const char*, int);
-void sqlite3_result_error16(sqlite3_context*, const void*, int);
-void sqlite3_result_error_toobig(sqlite3_context*);
-void sqlite3_result_error_nomem(sqlite3_context*);
-void sqlite3_result_error_code(sqlite3_context*, int);
-void sqlite3_result_int(sqlite3_context*, int);
-void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
-void sqlite3_result_null(sqlite3_context*);
-void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
-void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
-void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
-void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
-void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
-void sqlite3_result_zeroblob(sqlite3_context*, int n);
+SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
+SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
+SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
+SQLITE_API void sqlite3_result_null(sqlite3_context*);
+SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
 
 /*
-** CAPI3REF: Define New Collating Sequences {H16600} <S20300>
+** CAPI3REF: Define New Collating Sequences
 **
-** These functions are used to add new collation sequences to the
-** [database connection] specified as the first argument.
+** ^These functions add, remove, or modify a [collation] associated
+** with the [database connection] specified as the first argument.
 **
-** The name of the new collation sequence is specified as a UTF-8 string
+** ^The name of the collation is a UTF-8 string
 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
-** and a UTF-16 string for sqlite3_create_collation16(). In all cases
-** the name is passed as the second function argument.
+** and a UTF-16 string in native byte order for sqlite3_create_collation16().
+** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
+** considered to be the same name.
 **
-** The third argument may be one of the constants [SQLITE_UTF8],
-** [SQLITE_UTF16LE] or [SQLITE_UTF16BE], indicating that the user-supplied
-** routine expects to be passed pointers to strings encoded using UTF-8,
-** UTF-16 little-endian, or UTF-16 big-endian, respectively. The
-** third argument might also be [SQLITE_UTF16_ALIGNED] to indicate that
-** the routine expects pointers to 16-bit word aligned strings
-** of UTF-16 in the native byte order of the host computer.
+** ^(The third argument (eTextRep) must be one of the constants:
+** <ul>
+** <li> [SQLITE_UTF8],
+** <li> [SQLITE_UTF16LE],
+** <li> [SQLITE_UTF16BE],
+** <li> [SQLITE_UTF16], or
+** <li> [SQLITE_UTF16_ALIGNED].
+** </ul>)^
+** ^The eTextRep argument determines the encoding of strings passed
+** to the collating function callback, xCallback.
+** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
+** force strings to be UTF16 with native byte order.
+** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
+** on an even byte address.
 **
-** A pointer to the user supplied routine must be passed as the fifth
-** argument.  If it is NULL, this is the same as deleting the collation
-** sequence (so that SQLite cannot call it anymore).
-** Each time the application supplied function is invoked, it is passed
-** as its first parameter a copy of the void* passed as the fourth argument
-** to sqlite3_create_collation() or sqlite3_create_collation16().
+** ^The fourth argument, pArg, is an application data pointer that is passed
+** through as the first argument to the collating function callback.
 **
-** The remaining arguments to the application-supplied routine are two strings,
-** each represented by a (length, data) pair and encoded in the encoding
-** that was passed as the third argument when the collation sequence was
-** registered. {END}  The application defined collation routine should
-** return negative, zero or positive if the first string is less than,
-** equal to, or greater than the second string. i.e. (STRING1 - STRING2).
+** ^The fifth argument, xCallback, is a pointer to the collating function.
+** ^Multiple collating functions can be registered using the same name but
+** with different eTextRep parameters and SQLite will use whichever
+** function requires the least amount of data transformation.
+** ^If the xCallback argument is NULL then the collating function is
+** deleted.  ^When all collating functions having the same name are deleted,
+** that collation is no longer usable.
 **
-** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
-** except that it takes an extra argument which is a destructor for
-** the collation.  The destructor is called when the collation is
-** destroyed and is passed a copy of the fourth parameter void* pointer
-** of the sqlite3_create_collation_v2().
-** Collations are destroyed when they are overridden by later calls to the
-** collation creation functions or when the [database connection] is closed
-** using [sqlite3_close()].
+** ^The collating function callback is invoked with a copy of the pArg 
+** application data pointer and with two strings in the encoding specified
+** by the eTextRep argument.  The collating function must return an
+** integer that is negative, zero, or positive
+** if the first string is less than, equal to, or greater than the second,
+** respectively.  A collating function must always return the same answer
+** given the same inputs.  If two or more collating functions are registered
+** to the same collation name (using different eTextRep values) then all
+** must give an equivalent answer when invoked with equivalent strings.
+** The collating function must obey the following properties for all
+** strings A, B, and C:
 **
-** INVARIANTS:
+** <ol>
+** <li> If A==B then B==A.
+** <li> If A==B and B==C then A==C.
+** <li> If A&lt;B THEN B&gt;A.
+** <li> If A&lt;B and B&lt;C then A&lt;C.
+** </ol>
 **
-** {H16603} A successful call to the
-**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] interface
-**          registers function F as the comparison function used to
-**          implement collation X on the [database connection] B for
-**          databases having encoding E.
+** If a collating function fails any of the above constraints and that
+** collating function is  registered and used, then the behavior of SQLite
+** is undefined.
 **
-** {H16604} SQLite understands the X parameter to
-**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] as a zero-terminated
-**          UTF-8 string in which case is ignored for ASCII characters and
-**          is significant for non-ASCII characters.
+** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
+** with the addition that the xDestroy callback is invoked on pArg when
+** the collating function is deleted.
+** ^Collating functions are deleted when they are overridden by later
+** calls to the collation creation functions or when the
+** [database connection] is closed using [sqlite3_close()].
 **
-** {H16606} Successive calls to [sqlite3_create_collation_v2(B,X,E,P,F,D)]
-**          with the same values for B, X, and E, override prior values
-**          of P, F, and D.
+** ^The xDestroy callback is <u>not</u> called if the 
+** sqlite3_create_collation_v2() function fails.  Applications that invoke
+** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 
+** check the return code and dispose of the application data pointer
+** themselves rather than expecting SQLite to deal with it for them.
+** This is different from every other SQLite interface.  The inconsistency 
+** is unfortunate but cannot be changed without breaking backwards 
+** compatibility.
 **
-** {H16609} If the destructor D in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
-**          is not NULL then it is called with argument P when the
-**          collating function is dropped by SQLite.
-**
-** {H16612} A collating function is dropped when it is overloaded.
-**
-** {H16615} A collating function is dropped when the database connection
-**          is closed using [sqlite3_close()].
-**
-** {H16618} The pointer P in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
-**          is passed through as the first parameter to the comparison
-**          function F for all subsequent invocations of F.
-**
-** {H16621} A call to [sqlite3_create_collation(B,X,E,P,F)] is exactly
-**          the same as a call to [sqlite3_create_collation_v2()] with
-**          the same parameters and a NULL destructor.
-**
-** {H16624} Following a [sqlite3_create_collation_v2(B,X,E,P,F,D)],
-**          SQLite uses the comparison function F for all text comparison
-**          operations on the [database connection] B on text values that
-**          use the collating sequence named X.
-**
-** {H16627} The [sqlite3_create_collation16(B,X,E,P,F)] works the same
-**          as [sqlite3_create_collation(B,X,E,P,F)] except that the
-**          collation name X is understood as UTF-16 in native byte order
-**          instead of UTF-8.
-**
-** {H16630} When multiple comparison functions are available for the same
-**          collating sequence, SQLite chooses the one whose text encoding
-**          requires the least amount of conversion from the default
-**          text encoding of the database.
+** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
 */
-int sqlite3_create_collation(
+SQLITE_API int sqlite3_create_collation(
   sqlite3*, 
   const char *zName, 
   int eTextRep, 
-  void*,
+  void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*)
 );
-int sqlite3_create_collation_v2(
+SQLITE_API int sqlite3_create_collation_v2(
   sqlite3*, 
   const char *zName, 
   int eTextRep, 
-  void*,
+  void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*),
   void(*xDestroy)(void*)
 );
-int sqlite3_create_collation16(
+SQLITE_API int sqlite3_create_collation16(
   sqlite3*, 
   const void *zName,
   int eTextRep, 
-  void*,
+  void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*)
 );
 
 /*
-** CAPI3REF: Collation Needed Callbacks {H16700} <S20300>
+** CAPI3REF: Collation Needed Callbacks
 **
-** To avoid having to register all collation sequences before a database
+** ^To avoid having to register all collation sequences before a database
 ** can be used, a single callback function may be registered with the
-** [database connection] to be called whenever an undefined collation
+** [database connection] to be invoked whenever an undefined collation
 ** sequence is required.
 **
-** If the function is registered using the sqlite3_collation_needed() API,
+** ^If the function is registered using the sqlite3_collation_needed() API,
 ** then it is passed the names of undefined collation sequences as strings
-** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used,
+** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
 ** the names are passed as UTF-16 in machine native byte order.
-** A call to either function replaces any existing callback.
+** ^A call to either function replaces the existing collation-needed callback.
 **
-** When the callback is invoked, the first argument passed is a copy
+** ^(When the callback is invoked, the first argument passed is a copy
 ** of the second argument to sqlite3_collation_needed() or
 ** sqlite3_collation_needed16().  The second argument is the database
 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
 ** sequence function required.  The fourth parameter is the name of the
-** required collation sequence.
+** required collation sequence.)^
 **
 ** The callback function should register the desired collation using
 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
 ** [sqlite3_create_collation_v2()].
-**
-** INVARIANTS:
-**
-** {H16702} A successful call to [sqlite3_collation_needed(D,P,F)]
-**          or [sqlite3_collation_needed16(D,P,F)] causes
-**          the [database connection] D to invoke callback F with first
-**          parameter P whenever it needs a comparison function for a
-**          collating sequence that it does not know about.
-**
-** {H16704} Each successful call to [sqlite3_collation_needed()] or
-**          [sqlite3_collation_needed16()] overrides the callback registered
-**          on the same [database connection] by prior calls to either
-**          interface.
-**
-** {H16706} The name of the requested collating function passed in the
-**          4th parameter to the callback is in UTF-8 if the callback
-**          was registered using [sqlite3_collation_needed()] and
-**          is in UTF-16 native byte order if the callback was
-**          registered using [sqlite3_collation_needed16()].
 */
-int sqlite3_collation_needed(
+SQLITE_API int sqlite3_collation_needed(
   sqlite3*, 
   void*, 
   void(*)(void*,sqlite3*,int eTextRep,const char*)
 );
-int sqlite3_collation_needed16(
+SQLITE_API int sqlite3_collation_needed16(
   sqlite3*, 
   void*,
   void(*)(void*,sqlite3*,int eTextRep,const void*)
 );
 
+#ifdef SQLITE_HAS_CODEC
 /*
 ** Specify the key for an encrypted database.  This routine should be
 ** called right after sqlite3_open().
@@ -4874,7 +4393,7 @@ int sqlite3_collation_needed16(
 ** The code to implement this API is not available in the public release
 ** of SQLite.
 */
-int sqlite3_key(
+SQLITE_API int sqlite3_key(
   sqlite3 *db,                   /* Database to be rekeyed */
   const void *pKey, int nKey     /* The key */
 );
@@ -4887,13 +4406,32 @@ int sqlite3_key(
 ** The code to implement this API is not available in the public release
 ** of SQLite.
 */
-int sqlite3_rekey(
+SQLITE_API int sqlite3_rekey(
   sqlite3 *db,                   /* Database to be rekeyed */
   const void *pKey, int nKey     /* The new key */
 );
 
 /*
-** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410>
+** Specify the activation key for a SEE database.  Unless 
+** activated, none of the SEE routines will work.
+*/
+SQLITE_API void sqlite3_activate_see(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+#ifdef SQLITE_ENABLE_CEROD
+/*
+** Specify the activation key for a CEROD database.  Unless 
+** activated, none of the CEROD routines will work.
+*/
+SQLITE_API void sqlite3_activate_cerod(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+/*
+** CAPI3REF: Suspend Execution For A Short Time
 **
 ** The sqlite3_sleep() function causes the current thread to suspend execution
 ** for at least a number of milliseconds specified in its parameter.
@@ -4903,47 +4441,106 @@ int sqlite3_rekey(
 ** the nearest second. The number of milliseconds of sleep actually
 ** requested from the operating system is returned.
 **
-** SQLite implements this interface by calling the xSleep()
-** method of the default [sqlite3_vfs] object.
-**
-** INVARIANTS:
-**
-** {H10533} The [sqlite3_sleep(M)] interface invokes the xSleep
-**          method of the default [sqlite3_vfs|VFS] in order to
-**          suspend execution of the current thread for at least
-**          M milliseconds.
-**
-** {H10536} The [sqlite3_sleep(M)] interface returns the number of
-**          milliseconds of sleep actually requested of the operating
-**          system, which might be larger than the parameter M.
+** ^SQLite implements this interface by calling the xSleep()
+** method of the default [sqlite3_vfs] object.  If the xSleep() method
+** of the default VFS is not implemented correctly, or not implemented at
+** all, then the behavior of sqlite3_sleep() may deviate from the description
+** in the previous paragraphs.
 */
-int sqlite3_sleep(int);
+SQLITE_API int sqlite3_sleep(int);
 
 /*
-** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000>
+** CAPI3REF: Name Of The Folder Holding Temporary Files
 **
-** If this global variable is made to point to a string which is
+** ^(If this global variable is made to point to a string which is
 ** the name of a folder (a.k.a. directory), then all temporary files
-** created by SQLite will be placed in that directory.  If this variable
+** created by SQLite when using a built-in [sqlite3_vfs | VFS]
+** will be placed in that directory.)^  ^If this variable
 ** is a NULL pointer, then SQLite performs a search for an appropriate
 ** temporary file directory.
 **
-** It is not safe to modify this variable once a [database connection]
-** has been opened.  It is intended that this variable be set once
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
 ** as part of process initialization and before any SQLite interface
-** routines have been call and remain unchanged thereafter.
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [temp_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [temp_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from 
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [temp_store_directory pragma] should be avoided.
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
+** features that require the use of temporary files may fail.  Here is an
+** example of how to do this using C++ with the Windows Runtime:
+**
+** <blockquote><pre>
+** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
+** &nbsp;     TemporaryFolder->Path->Data();
+** char zPathBuf&#91;MAX_PATH + 1&#93;;
+** memset(zPathBuf, 0, sizeof(zPathBuf));
+** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
+** &nbsp;     NULL, NULL);
+** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
+** </pre></blockquote>
 */
-SQLITE_EXTERN char *sqlite3_temp_directory;
+SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
 
 /*
-** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200>
+** CAPI3REF: Name Of The Folder Holding Database Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all database files
+** specified with a relative pathname and created or accessed by
+** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
+** to be relative to that directory.)^ ^If this variable is a NULL
+** pointer, then SQLite assumes that all database files specified
+** with a relative pathname are relative to the current directory
+** for the process.  Only the windows VFS makes use of this global
+** variable; it is ignored by the unix VFS.
+**
+** Changing the value of this variable while a database connection is
+** open can result in a corrupt database.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [data_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [data_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from 
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [data_store_directory pragma] should be avoided.
+*/
+SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
+
+/*
+** CAPI3REF: Test For Auto-Commit Mode
 ** KEYWORDS: {autocommit mode}
 **
-** The sqlite3_get_autocommit() interface returns non-zero or
+** ^The sqlite3_get_autocommit() interface returns non-zero or
 ** zero if the given database connection is or is not in autocommit mode,
-** respectively.  Autocommit mode is on by default.
-** Autocommit mode is disabled by a [BEGIN] statement.
-** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
+** respectively.  ^Autocommit mode is on by default.
+** ^Autocommit mode is disabled by a [BEGIN] statement.
+** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
 **
 ** If certain kinds of errors occur on a statement within a multi-statement
 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
@@ -4952,180 +4549,143 @@ SQLITE_EXTERN char *sqlite3_temp_directory;
 ** find out whether SQLite automatically rolled back the transaction after
 ** an error is to use this function.
 **
-** INVARIANTS:
-**
-** {H12931} The [sqlite3_get_autocommit(D)] interface returns non-zero or
-**          zero if the [database connection] D is or is not in autocommit
-**          mode, respectively.
-**
-** {H12932} Autocommit mode is on by default.
-**
-** {H12933} Autocommit mode is disabled by a successful [BEGIN] statement.
-**
-** {H12934} Autocommit mode is enabled by a successful [COMMIT] or [ROLLBACK]
-**          statement.
-**
-** ASSUMPTIONS:
-**
-** {A12936} If another thread changes the autocommit status of the database
-**          connection while this routine is running, then the return value
-**          is undefined.
+** If another thread changes the autocommit status of the database
+** connection while this routine is running, then the return value
+** is undefined.
 */
-int sqlite3_get_autocommit(sqlite3*);
+SQLITE_API int sqlite3_get_autocommit(sqlite3*);
 
 /*
-** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600>
+** CAPI3REF: Find The Database Handle Of A Prepared Statement
 **
-** The sqlite3_db_handle interface returns the [database connection] handle
-** to which a [prepared statement] belongs.  The database handle returned by
-** sqlite3_db_handle is the same database handle that was the first argument
+** ^The sqlite3_db_handle interface returns the [database connection] handle
+** to which a [prepared statement] belongs.  ^The [database connection]
+** returned by sqlite3_db_handle is the same [database connection]
+** that was the first argument
 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
 ** create the statement in the first place.
-**
-** INVARIANTS:
-**
-** {H13123} The [sqlite3_db_handle(S)] interface returns a pointer
-**          to the [database connection] associated with the
-**          [prepared statement] S.
 */
-sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
 
 /*
-** CAPI3REF: Find the next prepared statement {H13140} <S60600>
+** CAPI3REF: Return The Filename For A Database Connection
 **
-** This interface returns a pointer to the next [prepared statement] after
-** pStmt associated with the [database connection] pDb.  If pStmt is NULL
+** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
+** associated with database N of connection D.  ^The main database file
+** has the name "main".  If there is no attached database N on the database
+** connection D, or if database N is a temporary or in-memory database, then
+** a NULL pointer is returned.
+**
+** ^The filename returned by this function is the output of the
+** xFullPathname method of the [VFS].  ^In other words, the filename
+** will be an absolute pathname, even if the filename used
+** to open the database originally was a URI or relative pathname.
+*/
+SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine if a database is read-only
+**
+** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
+** of connection D is read-only, 0 if it is read/write, or -1 if N is not
+** the name of a database on connection D.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Find the next prepared statement
+**
+** ^This interface returns a pointer to the next [prepared statement] after
+** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
 ** then this interface returns a pointer to the first prepared statement
-** associated with the database connection pDb.  If no prepared statement
+** associated with the database connection pDb.  ^If no prepared statement
 ** satisfies the conditions of this routine, it returns NULL.
 **
-** INVARIANTS:
-**
-** {H13143} If D is a [database connection] that holds one or more
-**          unfinalized [prepared statements] and S is a NULL pointer,
-**          then [sqlite3_next_stmt(D, S)] routine shall return a pointer
-**          to one of the prepared statements associated with D.
-**
-** {H13146} If D is a [database connection] that holds no unfinalized
-**          [prepared statements] and S is a NULL pointer, then
-**          [sqlite3_next_stmt(D, S)] routine shall return a NULL pointer.
-**
-** {H13149} If S is a [prepared statement] in the [database connection] D
-**          and S is not the last prepared statement in D, then
-**          [sqlite3_next_stmt(D, S)] routine shall return a pointer
-**          to the next prepared statement in D after S.
-**
-** {H13152} If S is the last [prepared statement] in the
-**          [database connection] D then the [sqlite3_next_stmt(D, S)]
-**          routine shall return a NULL pointer.
-**
-** ASSUMPTIONS:
-**
-** {A13154} The [database connection] pointer D in a call to
-**          [sqlite3_next_stmt(D,S)] must refer to an open database
-**          connection and in particular must not be a NULL pointer.
+** The [database connection] pointer D in a call to
+** [sqlite3_next_stmt(D,S)] must refer to an open database
+** connection and in particular must not be a NULL pointer.
 */
-sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
+SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
 
 /*
-** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400>
+** CAPI3REF: Commit And Rollback Notification Callbacks
 **
-** The sqlite3_commit_hook() interface registers a callback
-** function to be invoked whenever a transaction is committed.
-** Any callback set by a previous call to sqlite3_commit_hook()
+** ^The sqlite3_commit_hook() interface registers a callback
+** function to be invoked whenever a transaction is [COMMIT | committed].
+** ^Any callback set by a previous call to sqlite3_commit_hook()
 ** for the same database connection is overridden.
-** The sqlite3_rollback_hook() interface registers a callback
-** function to be invoked whenever a transaction is committed.
-** Any callback set by a previous call to sqlite3_commit_hook()
+** ^The sqlite3_rollback_hook() interface registers a callback
+** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
+** ^Any callback set by a previous call to sqlite3_rollback_hook()
 ** for the same database connection is overridden.
-** The pArg argument is passed through to the callback.
-** If the callback on a commit hook function returns non-zero,
+** ^The pArg argument is passed through to the callback.
+** ^If the callback on a commit hook function returns non-zero,
 ** then the commit is converted into a rollback.
 **
-** If another function was previously registered, its
-** pArg value is returned.  Otherwise NULL is returned.
+** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
+** return the P argument from the previous call of the same function
+** on the same [database connection] D, or NULL for
+** the first call for each function on D.
 **
+** The commit and rollback hook callbacks are not reentrant.
 ** The callback implementation must not do anything that will modify
 ** the database connection that invoked the callback.  Any actions
 ** to modify the database connection must be deferred until after the
 ** completion of the [sqlite3_step()] call that triggered the commit
 ** or rollback hook in the first place.
-** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
-** database connections for the meaning of "modify" in this paragraph.
+** Note that running any other SQL statements, including SELECT statements,
+** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
+** the database connections for the meaning of "modify" in this paragraph.
 **
-** Registering a NULL function disables the callback.
+** ^Registering a NULL function disables the callback.
 **
-** For the purposes of this API, a transaction is said to have been
+** ^When the commit hook callback routine returns zero, the [COMMIT]
+** operation is allowed to continue normally.  ^If the commit hook
+** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
+** ^The rollback hook is invoked on a rollback that results from a commit
+** hook returning non-zero, just as it would be with any other rollback.
+**
+** ^For the purposes of this API, a transaction is said to have been
 ** rolled back if an explicit "ROLLBACK" statement is executed, or
 ** an error or constraint causes an implicit rollback to occur.
-** The rollback callback is not invoked if a transaction is
+** ^The rollback callback is not invoked if a transaction is
 ** automatically rolled back because the database connection is closed.
-** The rollback callback is not invoked if a transaction is
-** rolled back because a commit callback returned non-zero.
-** <todo> Check on this </todo>
 **
-** INVARIANTS:
-**
-** {H12951} The [sqlite3_commit_hook(D,F,P)] interface registers the
-**          callback function F to be invoked with argument P whenever
-**          a transaction commits on the [database connection] D.
-**
-** {H12952} The [sqlite3_commit_hook(D,F,P)] interface returns the P argument
-**          from the previous call with the same [database connection] D,
-**          or NULL on the first call for a particular database connection D.
-**
-** {H12953} Each call to [sqlite3_commit_hook()] overwrites the callback
-**          registered by prior calls.
-**
-** {H12954} If the F argument to [sqlite3_commit_hook(D,F,P)] is NULL
-**          then the commit hook callback is canceled and no callback
-**          is invoked when a transaction commits.
-**
-** {H12955} If the commit callback returns non-zero then the commit is
-**          converted into a rollback.
-**
-** {H12961} The [sqlite3_rollback_hook(D,F,P)] interface registers the
-**          callback function F to be invoked with argument P whenever
-**          a transaction rolls back on the [database connection] D.
-**
-** {H12962} The [sqlite3_rollback_hook(D,F,P)] interface returns the P
-**          argument from the previous call with the same
-**          [database connection] D, or NULL on the first call
-**          for a particular database connection D.
-**
-** {H12963} Each call to [sqlite3_rollback_hook()] overwrites the callback
-**          registered by prior calls.
-**
-** {H12964} If the F argument to [sqlite3_rollback_hook(D,F,P)] is NULL
-**          then the rollback hook callback is canceled and no callback
-**          is invoked when a transaction rolls back.
+** See also the [sqlite3_update_hook()] interface.
 */
-void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
-void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
+SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
+SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
 
 /*
-** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400>
+** CAPI3REF: Data Change Notification Callbacks
 **
-** The sqlite3_update_hook() interface registers a callback function
+** ^The sqlite3_update_hook() interface registers a callback function
 ** with the [database connection] identified by the first argument
 ** to be invoked whenever a row is updated, inserted or deleted.
-** Any callback set by a previous call to this function
+** ^Any callback set by a previous call to this function
 ** for the same database connection is overridden.
 **
-** The second argument is a pointer to the function to invoke when a
+** ^The second argument is a pointer to the function to invoke when a
 ** row is updated, inserted or deleted.
-** The first argument to the callback is a copy of the third argument
+** ^The first argument to the callback is a copy of the third argument
 ** to sqlite3_update_hook().
-** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
+** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
 ** to be invoked.
-** The third and fourth arguments to the callback contain pointers to the
+** ^The third and fourth arguments to the callback contain pointers to the
 ** database and table name containing the affected row.
-** The final callback parameter is the [rowid] of the row.
-** In the case of an update, this is the [rowid] after the update takes place.
+** ^The final callback parameter is the [rowid] of the row.
+** ^In the case of an update, this is the [rowid] after the update takes place.
 **
-** The update hook is not invoked when internal system tables are
-** modified (i.e. sqlite_master and sqlite_sequence).
+** ^(The update hook is not invoked when internal system tables are
+** modified (i.e. sqlite_master and sqlite_sequence).)^
+**
+** ^In the current implementation, the update hook
+** is not invoked when duplication rows are deleted because of an
+** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
+** invoked when rows are deleted using the [truncate optimization].
+** The exceptions defined in this paragraph might change in a future
+** release of SQLite.
 **
 ** The update hook implementation must not do anything that will modify
 ** the database connection that invoked the update hook.  Any actions
@@ -5134,196 +4694,164 @@ void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
-** If another function was previously registered, its pArg value
-** is returned.  Otherwise NULL is returned.
+** ^The sqlite3_update_hook(D,C,P) function
+** returns the P argument from the previous call
+** on the same [database connection] D, or NULL for
+** the first call on D.
 **
-** INVARIANTS:
-**
-** {H12971} The [sqlite3_update_hook(D,F,P)] interface causes the callback
-**          function F to be invoked with first parameter P whenever
-**          a table row is modified, inserted, or deleted on
-**          the [database connection] D.
-**
-** {H12973} The [sqlite3_update_hook(D,F,P)] interface returns the value
-**          of P for the previous call on the same [database connection] D,
-**          or NULL for the first call.
-**
-** {H12975} If the update hook callback F in [sqlite3_update_hook(D,F,P)]
-**          is NULL then the no update callbacks are made.
-**
-** {H12977} Each call to [sqlite3_update_hook(D,F,P)] overrides prior calls
-**          to the same interface on the same [database connection] D.
-**
-** {H12979} The update hook callback is not invoked when internal system
-**          tables such as sqlite_master and sqlite_sequence are modified.
-**
-** {H12981} The second parameter to the update callback
-**          is one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
-**          depending on the operation that caused the callback to be invoked.
-**
-** {H12983} The third and fourth arguments to the callback contain pointers
-**          to zero-terminated UTF-8 strings which are the names of the
-**          database and table that is being updated.
-
-** {H12985} The final callback parameter is the [rowid] of the row after
-**          the change occurs.
+** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
+** interfaces.
 */
-void *sqlite3_update_hook(
+SQLITE_API void *sqlite3_update_hook(
   sqlite3*, 
   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
   void*
 );
 
 /*
-** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900>
-** KEYWORDS: {shared cache} {shared cache mode}
+** CAPI3REF: Enable Or Disable Shared Pager Cache
 **
-** This routine enables or disables the sharing of the database cache
+** ^(This routine enables or disables the sharing of the database cache
 ** and schema data structures between [database connection | connections]
 ** to the same database. Sharing is enabled if the argument is true
-** and disabled if the argument is false.
+** and disabled if the argument is false.)^
 **
-** Cache sharing is enabled and disabled for an entire process. {END}
+** ^Cache sharing is enabled and disabled for an entire process.
 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
 ** sharing was enabled or disabled for each thread separately.
 **
-** The cache sharing mode set by this interface effects all subsequent
+** ^(The cache sharing mode set by this interface effects all subsequent
 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
 ** Existing database connections continue use the sharing mode
-** that was in effect at the time they were opened.
+** that was in effect at the time they were opened.)^
 **
-** Virtual tables cannot be used with a shared cache.  When shared
-** cache is enabled, the [sqlite3_create_module()] API used to register
-** virtual tables will always return an error.
+** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
+** successfully.  An [error code] is returned otherwise.)^
 **
-** This routine returns [SQLITE_OK] if shared cache was enabled or disabled
-** successfully.  An [error code] is returned otherwise.
-**
-** Shared cache is disabled by default. But this might change in
+** ^Shared cache is disabled by default. But this might change in
 ** future releases of SQLite.  Applications that care about shared
 ** cache setting should set it explicitly.
 **
-** INVARIANTS:
-**
-** {H10331} A successful invocation of [sqlite3_enable_shared_cache(B)]
-**          will enable or disable shared cache mode for any subsequently
-**          created [database connection] in the same process.
-**
-** {H10336} When shared cache is enabled, the [sqlite3_create_module()]
-**          interface will always return an error.
-**
-** {H10337} The [sqlite3_enable_shared_cache(B)] interface returns
-**          [SQLITE_OK] if shared cache was enabled or disabled successfully.
-**
-** {H10339} Shared cache is disabled by default.
+** See Also:  [SQLite Shared-Cache Mode]
 */
-int sqlite3_enable_shared_cache(int);
+SQLITE_API int sqlite3_enable_shared_cache(int);
 
 /*
-** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220>
+** CAPI3REF: Attempt To Free Heap Memory
 **
-** The sqlite3_release_memory() interface attempts to free N bytes
+** ^The sqlite3_release_memory() interface attempts to free N bytes
 ** of heap memory by deallocating non-essential memory allocations
-** held by the database library. {END}  Memory used to cache database
+** held by the database library.   Memory used to cache database
 ** pages to improve performance is an example of non-essential memory.
-** sqlite3_release_memory() returns the number of bytes actually freed,
+** ^sqlite3_release_memory() returns the number of bytes actually freed,
 ** which might be more or less than the amount requested.
+** ^The sqlite3_release_memory() routine is a no-op returning zero
+** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
 **
-** INVARIANTS:
-**
-** {H17341} The [sqlite3_release_memory(N)] interface attempts to
-**          free N bytes of heap memory by deallocating non-essential
-**          memory allocations held by the database library.
-**
-** {H16342} The [sqlite3_release_memory(N)] returns the number
-**          of bytes actually freed, which might be more or less
-**          than the amount requested.
+** See also: [sqlite3_db_release_memory()]
 */
-int sqlite3_release_memory(int);
+SQLITE_API int sqlite3_release_memory(int);
 
 /*
-** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220>
+** CAPI3REF: Free Memory Used By A Database Connection
 **
-** The sqlite3_soft_heap_limit() interface places a "soft" limit
-** on the amount of heap memory that may be allocated by SQLite.
-** If an internal allocation is requested that would exceed the
-** soft heap limit, [sqlite3_release_memory()] is invoked one or
-** more times to free up some space before the allocation is performed.
+** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
+** memory as possible from database connection D. Unlike the
+** [sqlite3_release_memory()] interface, this interface is effect even
+** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
+** omitted.
 **
-** The limit is called "soft", because if [sqlite3_release_memory()]
-** cannot free sufficient memory to prevent the limit from being exceeded,
-** the memory is allocated anyway and the current operation proceeds.
-**
-** A negative or zero value for N means that there is no soft heap limit and
-** [sqlite3_release_memory()] will only be called when memory is exhausted.
-** The default value for the soft heap limit is zero.
-**
-** SQLite makes a best effort to honor the soft heap limit.
-** But if the soft heap limit cannot be honored, execution will
-** continue without error or notification.  This is why the limit is
-** called a "soft" limit.  It is advisory only.
-**
-** Prior to SQLite version 3.5.0, this routine only constrained the memory
-** allocated by a single thread - the same thread in which this routine
-** runs.  Beginning with SQLite version 3.5.0, the soft heap limit is
-** applied to all threads. The value specified for the soft heap limit
-** is an upper bound on the total memory allocation for all threads. In
-** version 3.5.0 there is no mechanism for limiting the heap usage for
-** individual threads.
-**
-** INVARIANTS:
-**
-** {H16351} The [sqlite3_soft_heap_limit(N)] interface places a soft limit
-**          of N bytes on the amount of heap memory that may be allocated
-**          using [sqlite3_malloc()] or [sqlite3_realloc()] at any point
-**          in time.
-**
-** {H16352} If a call to [sqlite3_malloc()] or [sqlite3_realloc()] would
-**          cause the total amount of allocated memory to exceed the
-**          soft heap limit, then [sqlite3_release_memory()] is invoked
-**          in an attempt to reduce the memory usage prior to proceeding
-**          with the memory allocation attempt.
-**
-** {H16353} Calls to [sqlite3_malloc()] or [sqlite3_realloc()] that trigger
-**          attempts to reduce memory usage through the soft heap limit
-**          mechanism continue even if the attempt to reduce memory
-**          usage is unsuccessful.
-**
-** {H16354} A negative or zero value for N in a call to
-**          [sqlite3_soft_heap_limit(N)] means that there is no soft
-**          heap limit and [sqlite3_release_memory()] will only be
-**          called when memory is completely exhausted.
-**
-** {H16355} The default value for the soft heap limit is zero.
-**
-** {H16358} Each call to [sqlite3_soft_heap_limit(N)] overrides the
-**          values set by all prior calls.
+** See also: [sqlite3_release_memory()]
 */
-void sqlite3_soft_heap_limit(int);
+SQLITE_API int sqlite3_db_release_memory(sqlite3*);
 
 /*
-** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300>
+** CAPI3REF: Impose A Limit On Heap Size
 **
-** This routine returns metadata about a specific column of a specific
+** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
+** soft limit on the amount of heap memory that may be allocated by SQLite.
+** ^SQLite strives to keep heap memory utilization below the soft heap
+** limit by reducing the number of pages held in the page cache
+** as heap memory usages approaches the limit.
+** ^The soft heap limit is "soft" because even though SQLite strives to stay
+** below the limit, it will exceed the limit rather than generate
+** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
+** is advisory only.
+**
+** ^The return value from sqlite3_soft_heap_limit64() is the size of
+** the soft heap limit prior to the call, or negative in the case of an
+** error.  ^If the argument N is negative
+** then no change is made to the soft heap limit.  Hence, the current
+** size of the soft heap limit can be determined by invoking
+** sqlite3_soft_heap_limit64() with a negative argument.
+**
+** ^If the argument N is zero then the soft heap limit is disabled.
+**
+** ^(The soft heap limit is not enforced in the current implementation
+** if one or more of following conditions are true:
+**
+** <ul>
+** <li> The soft heap limit is set to zero.
+** <li> Memory accounting is disabled using a combination of the
+**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
+**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
+** <li> An alternative page cache implementation is specified using
+**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
+** <li> The page cache allocates from its own memory pool supplied
+**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
+**      from the heap.
+** </ul>)^
+**
+** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
+** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
+** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
+** the soft heap limit is enforced on every memory allocation.  Without
+** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
+** when memory is allocated by the page cache.  Testing suggests that because
+** the page cache is the predominate memory user in SQLite, most
+** applications will achieve adequate soft heap limit enforcement without
+** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
+**
+** The circumstances under which SQLite will enforce the soft heap limit may
+** changes in future releases of SQLite.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
+
+/*
+** CAPI3REF: Deprecated Soft Heap Limit Interface
+** DEPRECATED
+**
+** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
+** interface.  This routine is provided for historical compatibility
+** only.  All new applications should use the
+** [sqlite3_soft_heap_limit64()] interface rather than this one.
+*/
+SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
+
+
+/*
+** CAPI3REF: Extract Metadata About A Column Of A Table
+**
+** ^This routine returns metadata about a specific column of a specific
 ** database table accessible using the [database connection] handle
 ** passed as the first function argument.
 **
-** The column is identified by the second, third and fourth parameters to
-** this function. The second parameter is either the name of the database
-** (i.e. "main", "temp" or an attached database) containing the specified
-** table or NULL. If it is NULL, then all attached databases are searched
+** ^The column is identified by the second, third and fourth parameters to
+** this function. ^The second parameter is either the name of the database
+** (i.e. "main", "temp", or an attached database) containing the specified
+** table or NULL. ^If it is NULL, then all attached databases are searched
 ** for the table using the same algorithm used by the database engine to
 ** resolve unqualified table references.
 **
-** The third and fourth parameters to this function are the table and column
+** ^The third and fourth parameters to this function are the table and column
 ** name of the desired column, respectively. Neither of these parameters
 ** may be NULL.
 **
-** Metadata is returned by writing to the memory locations passed as the 5th
-** and subsequent parameters to this function. Any of these arguments may be
+** ^Metadata is returned by writing to the memory locations passed as the 5th
+** and subsequent parameters to this function. ^Any of these arguments may be
 ** NULL, in which case the corresponding element of metadata is omitted.
 **
-** <blockquote>
+** ^(<blockquote>
 ** <table border="1">
 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
 **
@@ -5333,17 +4861,17 @@ void sqlite3_soft_heap_limit(int);
 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
 ** </table>
-** </blockquote>
+** </blockquote>)^
 **
-** The memory pointed to by the character pointers returned for the
+** ^The memory pointed to by the character pointers returned for the
 ** declaration type and collation sequence is valid only until the next
 ** call to any SQLite API function.
 **
-** If the specified table is actually a view, an [error code] is returned.
+** ^If the specified table is actually a view, an [error code] is returned.
 **
-** If the specified column is "rowid", "oid" or "_rowid_" and an
+** ^If the specified column is "rowid", "oid" or "_rowid_" and an
 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
-** parameters are set for the explicitly declared column. If there is no
+** parameters are set for the explicitly declared column. ^(If there is no
 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
 ** parameters are set as follows:
 **
@@ -5353,17 +4881,17 @@ void sqlite3_soft_heap_limit(int);
 **     not null: 0
 **     primary key: 1
 **     auto increment: 0
-** </pre>
+** </pre>)^
 **
-** This function may load one or more schemas from database files. If an
+** ^(This function may load one or more schemas from database files. If an
 ** error occurs during this process, or if the requested table or column
 ** cannot be found, an [error code] is returned and an error message left
-** in the [database connection] (to be retrieved using sqlite3_errmsg()).
+** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
 **
-** This API is only available if the library was compiled with the
+** ^This API is only available if the library was compiled with the
 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
 */
-int sqlite3_table_column_metadata(
+SQLITE_API int sqlite3_table_column_metadata(
   sqlite3 *db,                /* Connection handle */
   const char *zDbName,        /* Database name or NULL */
   const char *zTableName,     /* Table name */
@@ -5376,32 +4904,31 @@ int sqlite3_table_column_metadata(
 );
 
 /*
-** CAPI3REF: Load An Extension {H12600} <S20500>
+** CAPI3REF: Load An Extension
 **
-** This interface loads an SQLite extension library from the named file.
+** ^This interface loads an SQLite extension library from the named file.
 **
-** {H12601} The sqlite3_load_extension() interface attempts to load an
-**          SQLite extension library contained in the file zFile.
+** ^The sqlite3_load_extension() interface attempts to load an
+** SQLite extension library contained in the file zFile.
 **
-** {H12602} The entry point is zProc.
+** ^The entry point is zProc.
+** ^zProc may be 0, in which case the name of the entry point
+** defaults to "sqlite3_extension_init".
+** ^The sqlite3_load_extension() interface returns
+** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
+** ^If an error occurs and pzErrMsg is not 0, then the
+** [sqlite3_load_extension()] interface shall attempt to
+** fill *pzErrMsg with error message text stored in memory
+** obtained from [sqlite3_malloc()]. The calling function
+** should free this memory by calling [sqlite3_free()].
 **
-** {H12603} zProc may be 0, in which case the name of the entry point
-**          defaults to "sqlite3_extension_init".
+** ^Extension loading must be enabled using
+** [sqlite3_enable_load_extension()] prior to calling this API,
+** otherwise an error will be returned.
 **
-** {H12604} The sqlite3_load_extension() interface shall return
-**          [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
-**
-** {H12605} If an error occurs and pzErrMsg is not 0, then the
-**          [sqlite3_load_extension()] interface shall attempt to
-**          fill *pzErrMsg with error message text stored in memory
-**          obtained from [sqlite3_malloc()]. {END}  The calling function
-**          should free this memory by calling [sqlite3_free()].
-**
-** {H12606} Extension loading must be enabled using
-**          [sqlite3_enable_load_extension()] prior to calling this API,
-**          otherwise an error will be returned.
+** See also the [load_extension() SQL function].
 */
-int sqlite3_load_extension(
+SQLITE_API int sqlite3_load_extension(
   sqlite3 *db,          /* Load the extension into this database connection */
   const char *zFile,    /* Name of the shared library containing extension */
   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
@@ -5409,67 +4936,66 @@ int sqlite3_load_extension(
 );
 
 /*
-** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500>
+** CAPI3REF: Enable Or Disable Extension Loading
 **
-** So as not to open security holes in older applications that are
+** ^So as not to open security holes in older applications that are
 ** unprepared to deal with extension loading, and as a means of disabling
 ** extension loading while evaluating user-entered SQL, the following API
 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
 **
-** Extension loading is off by default. See ticket #1863.
-**
-** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1
-**          to turn extension loading on and call it with onoff==0 to turn
-**          it back off again.
-**
-** {H12622} Extension loading is off by default.
+** ^Extension loading is off by default. See ticket #1863.
+** ^Call the sqlite3_enable_load_extension() routine with onoff==1
+** to turn extension loading on and call it with onoff==0 to turn
+** it back off again.
 */
-int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
 
 /*
-** CAPI3REF: Automatically Load An Extensions {H12640} <S20500>
+** CAPI3REF: Automatically Load Statically Linked Extensions
 **
-** This API can be invoked at program startup in order to register
-** one or more statically linked extensions that will be available
-** to all new [database connections]. {END}
+** ^This interface causes the xEntryPoint() function to be invoked for
+** each new [database connection] that is created.  The idea here is that
+** xEntryPoint() is the entry point for a statically linked SQLite extension
+** that is to be automatically loaded into all new database connections.
 **
-** This routine stores a pointer to the extension in an array that is
-** obtained from [sqlite3_malloc()].  If you run a memory leak checker
-** on your program and it reports a leak because of this array, invoke
-** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory.
+** ^(Even though the function prototype shows that xEntryPoint() takes
+** no arguments and returns void, SQLite invokes xEntryPoint() with three
+** arguments and expects and integer result as if the signature of the
+** entry point where as follows:
 **
-** {H12641} This function registers an extension entry point that is
-**          automatically invoked whenever a new [database connection]
-**          is opened using [sqlite3_open()], [sqlite3_open16()],
-**          or [sqlite3_open_v2()].
+** <blockquote><pre>
+** &nbsp;  int xEntryPoint(
+** &nbsp;    sqlite3 *db,
+** &nbsp;    const char **pzErrMsg,
+** &nbsp;    const struct sqlite3_api_routines *pThunk
+** &nbsp;  );
+** </pre></blockquote>)^
 **
-** {H12642} Duplicate extensions are detected so calling this routine
-**          multiple times with the same extension is harmless.
+** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
+** point to an appropriate error message (obtained from [sqlite3_mprintf()])
+** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
+** is NULL before calling the xEntryPoint().  ^SQLite will invoke
+** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
+** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
+** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
 **
-** {H12643} This routine stores a pointer to the extension in an array
-**          that is obtained from [sqlite3_malloc()].
+** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
+** on the list of automatic extensions is a harmless no-op. ^No entry point
+** will be called more than once for each database connection that is opened.
 **
-** {H12644} Automatic extensions apply across all threads.
+** See also: [sqlite3_reset_auto_extension()].
 */
-int sqlite3_auto_extension(void (*xEntryPoint)(void));
+SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
 
 /*
-** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500>
+** CAPI3REF: Reset Automatic Extension Loading
 **
-** This function disables all previously registered automatic
-** extensions. {END}  It undoes the effect of all prior
-** [sqlite3_auto_extension()] calls.
-**
-** {H12661} This function disables all previously registered
-**          automatic extensions.
-**
-** {H12662} This function disables automatic extensions in all threads.
+** ^This interface disables all automatic extensions previously
+** registered using [sqlite3_auto_extension()].
 */
-void sqlite3_reset_auto_extension(void);
+SQLITE_API void sqlite3_reset_auto_extension(void);
 
 /*
-****** EXPERIMENTAL - subject to change without notice **************
-**
 ** The interface to the virtual-table mechanism is currently considered
 ** to be experimental.  The interface might change in incompatible ways.
 ** If this is a problem for you, do not use the interface at this time.
@@ -5487,16 +5013,20 @@ typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
 typedef struct sqlite3_module sqlite3_module;
 
 /*
-** CAPI3REF: Virtual Table Object {H18000} <S20400>
-** KEYWORDS: sqlite3_module
-** EXPERIMENTAL
+** CAPI3REF: Virtual Table Object
+** KEYWORDS: sqlite3_module {virtual table module}
 **
-** A module is a class of virtual tables.  Each module is defined
-** by an instance of the following structure.  This structure consists
-** mostly of methods for the module.
+** This structure, sometimes called a "virtual table module", 
+** defines the implementation of a [virtual tables].  
+** This structure consists mostly of methods for the module.
 **
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
+** ^A virtual table module is created by filling in a persistent
+** instance of this structure and passing a pointer to that instance
+** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
+** ^The registration remains valid until it is replaced by a different
+** module or until the [database connection] closes.  The content
+** of this structure must not change while it is registered with
+** any database connection.
 */
 struct sqlite3_module {
   int iVersion;
@@ -5526,59 +5056,65 @@ struct sqlite3_module {
                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
                        void **ppArg);
   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
+  /* The methods above are in version 1 of the sqlite_module object. Those 
+  ** below are for version 2 and greater. */
+  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
+  int (*xRelease)(sqlite3_vtab *pVTab, int);
+  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
 };
 
 /*
-** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400>
+** CAPI3REF: Virtual Table Indexing Information
 ** KEYWORDS: sqlite3_index_info
-** EXPERIMENTAL
 **
-** The sqlite3_index_info structure and its substructures is used to
-** pass information into and receive the reply from the xBestIndex
-** method of an sqlite3_module.  The fields under **Inputs** are the
+** The sqlite3_index_info structure and its substructures is used as part
+** of the [virtual table] interface to
+** pass information into and receive the reply from the [xBestIndex]
+** method of a [virtual table module].  The fields under **Inputs** are the
 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
 ** results into the **Outputs** fields.
 **
-** The aConstraint[] array records WHERE clause constraints of the form:
+** ^(The aConstraint[] array records WHERE clause constraints of the form:
 **
-** <pre>column OP expr</pre>
+** <blockquote>column OP expr</blockquote>
 **
-** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.  The particular operator is
-** stored in aConstraint[].op.  The index of the column is stored in
-** aConstraint[].iColumn.  aConstraint[].usable is TRUE if the
+** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
+** stored in aConstraint[].op using one of the
+** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
+** ^(The index of the column is stored in
+** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
 ** expr on the right-hand side can be evaluated (and thus the constraint
-** is usable) and false if it cannot.
+** is usable) and false if it cannot.)^
 **
-** The optimizer automatically inverts terms of the form "expr OP column"
+** ^The optimizer automatically inverts terms of the form "expr OP column"
 ** and makes other simplifications to the WHERE clause in an attempt to
 ** get as many WHERE clause terms into the form shown above as possible.
-** The aConstraint[] array only reports WHERE clause terms in the correct
-** form that refer to the particular virtual table being queried.
+** ^The aConstraint[] array only reports WHERE clause terms that are
+** relevant to the particular virtual table being queried.
 **
-** Information about the ORDER BY clause is stored in aOrderBy[].
-** Each term of aOrderBy records a column of the ORDER BY clause.
+** ^Information about the ORDER BY clause is stored in aOrderBy[].
+** ^Each term of aOrderBy records a column of the ORDER BY clause.
 **
-** The xBestIndex method must fill aConstraintUsage[] with information
-** about what parameters to pass to xFilter.  If argvIndex>0 then
+** The [xBestIndex] method must fill aConstraintUsage[] with information
+** about what parameters to pass to xFilter.  ^If argvIndex>0 then
 ** the right-hand side of the corresponding aConstraint[] is evaluated
-** and becomes the argvIndex-th entry in argv.  If aConstraintUsage[].omit
+** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
 ** is true, then the constraint is assumed to be fully handled by the
-** virtual table and is not checked again by SQLite.
+** virtual table and is not checked again by SQLite.)^
 **
-** The idxNum and idxPtr values are recorded and passed into xFilter.
-** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true.
+** ^The idxNum and idxPtr values are recorded and passed into the
+** [xFilter] method.
+** ^[sqlite3_free()] is used to free idxPtr if and only if
+** needToFreeIdxPtr is true.
 **
-** The orderByConsumed means that output from xFilter will occur in
+** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
 ** the correct order to satisfy the ORDER BY clause so that no separate
 ** sorting step is required.
 **
-** The estimatedCost value is an estimate of the cost of doing the
+** ^The estimatedCost value is an estimate of the cost of doing the
 ** particular lookup.  A full scan of a table with N entries should have
 ** a cost of N.  A binary search of a table of N entries should have a
 ** cost of approximately log(N).
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
 */
 struct sqlite3_index_info {
   /* Inputs */
@@ -5605,6 +5141,15 @@ struct sqlite3_index_info {
   int orderByConsumed;       /* True if output is already ordered */
   double estimatedCost;      /* Estimated cost of using this index */
 };
+
+/*
+** CAPI3REF: Virtual Table Constraint Operator Codes
+**
+** These macros defined the allowed values for the
+** [sqlite3_index_info].aConstraint[].op field.  Each value represents
+** an operator that is part of a constraint term in the wHERE clause of
+** a query that uses a [virtual table].
+*/
 #define SQLITE_INDEX_CONSTRAINT_EQ    2
 #define SQLITE_INDEX_CONSTRAINT_GT    4
 #define SQLITE_INDEX_CONSTRAINT_LE    8
@@ -5613,87 +5158,85 @@ struct sqlite3_index_info {
 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
 
 /*
-** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400>
-** EXPERIMENTAL
+** CAPI3REF: Register A Virtual Table Implementation
 **
-** This routine is used to register a new module name with a
-** [database connection].  Module names must be registered before
-** creating new virtual tables on the module, or before using
-** preexisting virtual tables of the module.
+** ^These routines are used to register a new [virtual table module] name.
+** ^Module names must be registered before
+** creating a new [virtual table] using the module and before using a
+** preexisting [virtual table] for the module.
 **
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
+** ^The module name is registered on the [database connection] specified
+** by the first parameter.  ^The name of the module is given by the 
+** second parameter.  ^The third parameter is a pointer to
+** the implementation of the [virtual table module].   ^The fourth
+** parameter is an arbitrary client data pointer that is passed through
+** into the [xCreate] and [xConnect] methods of the virtual table module
+** when a new virtual table is be being created or reinitialized.
+**
+** ^The sqlite3_create_module_v2() interface has a fifth parameter which
+** is a pointer to a destructor for the pClientData.  ^SQLite will
+** invoke the destructor function (if it is not NULL) when SQLite
+** no longer needs the pClientData pointer.  ^The destructor will also
+** be invoked if the call to sqlite3_create_module_v2() fails.
+** ^The sqlite3_create_module()
+** interface is equivalent to sqlite3_create_module_v2() with a NULL
+** destructor.
 */
-SQLITE_EXPERIMENTAL int sqlite3_create_module(
+SQLITE_API int sqlite3_create_module(
   sqlite3 *db,               /* SQLite connection to register module with */
   const char *zName,         /* Name of the module */
-  const sqlite3_module *,    /* Methods for the module */
-  void *                     /* Client data for xCreate/xConnect */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData          /* Client data for xCreate/xConnect */
 );
-
-/*
-** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400>
-** EXPERIMENTAL
-**
-** This routine is identical to the [sqlite3_create_module()] method above,
-** except that it allows a destructor function to be specified. It is
-** even more experimental than the rest of the virtual tables API.
-*/
-SQLITE_EXPERIMENTAL int sqlite3_create_module_v2(
+SQLITE_API int sqlite3_create_module_v2(
   sqlite3 *db,               /* SQLite connection to register module with */
   const char *zName,         /* Name of the module */
-  const sqlite3_module *,    /* Methods for the module */
-  void *,                    /* Client data for xCreate/xConnect */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData,         /* Client data for xCreate/xConnect */
   void(*xDestroy)(void*)     /* Module destructor function */
 );
 
 /*
-** CAPI3REF: Virtual Table Instance Object {H18010} <S20400>
+** CAPI3REF: Virtual Table Instance Object
 ** KEYWORDS: sqlite3_vtab
-** EXPERIMENTAL
 **
-** Every module implementation uses a subclass of the following structure
-** to describe a particular instance of the module.  Each subclass will
+** Every [virtual table module] implementation uses a subclass
+** of this object to describe a particular instance
+** of the [virtual table].  Each subclass will
 ** be tailored to the specific needs of the module implementation.
 ** The purpose of this superclass is to define certain fields that are
 ** common to all module implementations.
 **
-** Virtual tables methods can set an error message by assigning a
+** ^Virtual tables methods can set an error message by assigning a
 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
 ** take care that any prior string is freed by a call to [sqlite3_free()]
-** prior to assigning a new string to zErrMsg.  After the error message
+** prior to assigning a new string to zErrMsg.  ^After the error message
 ** is delivered up to the client application, the string will be automatically
-** freed by sqlite3_free() and the zErrMsg field will be zeroed.  Note
-** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
-** since virtual tables are commonly implemented in loadable extensions which
-** do not have access to sqlite3MPrintf() or sqlite3Free().
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
+** freed by sqlite3_free() and the zErrMsg field will be zeroed.
 */
 struct sqlite3_vtab {
   const sqlite3_module *pModule;  /* The module for this virtual table */
-  int nRef;                       /* Used internally */
+  int nRef;                       /* NO LONGER USED */
   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
   /* Virtual table implementations will typically add additional fields */
 };
 
 /*
-** CAPI3REF: Virtual Table Cursor Object  {H18020} <S20400>
-** KEYWORDS: sqlite3_vtab_cursor
-** EXPERIMENTAL
+** CAPI3REF: Virtual Table Cursor Object
+** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
 **
-** Every module implementation uses a subclass of the following structure
-** to describe cursors that point into the virtual table and are used
+** Every [virtual table module] implementation uses a subclass of the
+** following structure to describe cursors that point into the
+** [virtual table] and are used
 ** to loop through the virtual table.  Cursors are created using the
-** xOpen method of the module.  Each module implementation will define
+** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
+** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
+** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
+** of the module.  Each module implementation will define
 ** the content of a cursor structure to suit its own needs.
 **
 ** This superclass exists in order to define fields of the cursor that
 ** are common to all implementations.
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
 */
 struct sqlite3_vtab_cursor {
   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
@@ -5701,38 +5244,32 @@ struct sqlite3_vtab_cursor {
 };
 
 /*
-** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400>
-** EXPERIMENTAL
+** CAPI3REF: Declare The Schema Of A Virtual Table
 **
-** The xCreate and xConnect methods of a module use the following API
+** ^The [xCreate] and [xConnect] methods of a
+** [virtual table module] call this interface
 ** to declare the format (the names and datatypes of the columns) of
 ** the virtual tables they implement.
-**
-** This interface is experimental and is subject to change or
-** removal in future releases of SQLite.
 */
-SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable);
+SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
 
 /*
-** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400>
-** EXPERIMENTAL
+** CAPI3REF: Overload A Function For A Virtual Table
 **
-** Virtual tables can provide alternative implementations of functions
-** using the xFindFunction method.  But global versions of those functions
-** must exist in order to be overloaded.
+** ^(Virtual tables can provide alternative implementations of functions
+** using the [xFindFunction] method of the [virtual table module].  
+** But global versions of those functions
+** must exist in order to be overloaded.)^
 **
-** This API makes sure a global version of a function with a particular
+** ^(This API makes sure a global version of a function with a particular
 ** name and number of parameters exists.  If no such function exists
-** before this API is called, a new function is created.  The implementation
+** before this API is called, a new function is created.)^  ^The implementation
 ** of the new function always causes an exception to be thrown.  So
 ** the new function is not good for anything by itself.  Its only
 ** purpose is to be a placeholder function that can be overloaded
-** by virtual tables.
-**
-** This API should be considered part of the virtual table interface,
-** which is experimental and subject to change.
+** by a [virtual table].
 */
-SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
+SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
 
 /*
 ** The interface to the virtual-table mechanism defined above (back up
@@ -5742,91 +5279,79 @@ SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncNam
 **
 ** When the virtual-table mechanism stabilizes, we will declare the
 ** interface fixed, support it indefinitely, and remove this comment.
-**
-****** EXPERIMENTAL - subject to change without notice **************
 */
 
 /*
-** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230>
+** CAPI3REF: A Handle To An Open BLOB
 ** KEYWORDS: {BLOB handle} {BLOB handles}
 **
 ** An instance of this object represents an open BLOB on which
 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
-** Objects of this type are created by [sqlite3_blob_open()]
+** ^Objects of this type are created by [sqlite3_blob_open()]
 ** and destroyed by [sqlite3_blob_close()].
-** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
+** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
 ** can be used to read or write small subsections of the BLOB.
-** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
+** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
 */
 typedef struct sqlite3_blob sqlite3_blob;
 
 /*
-** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230>
+** CAPI3REF: Open A BLOB For Incremental I/O
 **
-** This interfaces opens a [BLOB handle | handle] to the BLOB located
+** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
 ** in row iRow, column zColumn, table zTable in database zDb;
 ** in other words, the same BLOB that would be selected by:
 **
 ** <pre>
 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
-** </pre> {END}
+** </pre>)^
 **
-** If the flags parameter is non-zero, the the BLOB is opened for read
-** and write access. If it is zero, the BLOB is opened for read access.
+** ^If the flags parameter is non-zero, then the BLOB is opened for read
+** and write access. ^If it is zero, the BLOB is opened for read access.
+** ^It is not possible to open a column that is part of an index or primary 
+** key for writing. ^If [foreign key constraints] are enabled, it is 
+** not possible to open a column that is part of a [child key] for writing.
 **
-** Note that the database name is not the filename that contains
+** ^Note that the database name is not the filename that contains
 ** the database but rather the symbolic name of the database that
-** is assigned when the database is connected using [ATTACH].
-** For the main database file, the database name is "main".
-** For TEMP tables, the database name is "temp".
+** appears after the AS keyword when the database is connected using [ATTACH].
+** ^For the main database file, the database name is "main".
+** ^For TEMP tables, the database name is "temp".
 **
-** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
-** to *ppBlob. Otherwise an [error code] is returned and any value written
-** to *ppBlob should not be used by the caller.
-** This function sets the [database connection] error code and message
-** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()].
+** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
+** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
+** to be a null pointer.)^
+** ^This function sets the [database connection] error code and message
+** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
+** functions. ^Note that the *ppBlob variable is always initialized in a
+** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
+** regardless of the success or failure of this routine.
 **
-** If the row that a BLOB handle points to is modified by an
+** ^(If the row that a BLOB handle points to is modified by an
 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
 ** then the BLOB handle is marked as "expired".
 ** This is true if any column of the row is changed, even a column
-** other than the one the BLOB handle is open on.
-** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
-** a expired BLOB handle fail with an return code of [SQLITE_ABORT].
-** Changes written into a BLOB prior to the BLOB expiring are not
-** rollback by the expiration of the BLOB.  Such changes will eventually
-** commit if the transaction continues to completion.
+** other than the one the BLOB handle is open on.)^
+** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
+** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
+** ^(Changes written into a BLOB prior to the BLOB expiring are not
+** rolled back by the expiration of the BLOB.  Such changes will eventually
+** commit if the transaction continues to completion.)^
 **
-** INVARIANTS:
+** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
+** the opened blob.  ^The size of a blob may not be changed by this
+** interface.  Use the [UPDATE] SQL command to change the size of a
+** blob.
 **
-** {H17813} A successful invocation of the [sqlite3_blob_open(D,B,T,C,R,F,P)]
-**          interface shall open an [sqlite3_blob] object P on the BLOB
-**          in column C of the table T in the database B on
-**          the [database connection] D.
+** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
+** and the built-in [zeroblob] SQL function can be used, if desired,
+** to create an empty, zero-filled blob in which to read or write using
+** this interface.
 **
-** {H17814} A successful invocation of [sqlite3_blob_open(D,...)] shall start
-**          a new transaction on the [database connection] D if that
-**          connection is not already in a transaction.
-**
-** {H17816} The [sqlite3_blob_open(D,B,T,C,R,F,P)] interface shall open
-**          the BLOB for read and write access if and only if the F
-**          parameter is non-zero.
-**
-** {H17819} The [sqlite3_blob_open()] interface shall return [SQLITE_OK] on
-**          success and an appropriate [error code] on failure.
-**
-** {H17821} If an error occurs during evaluation of [sqlite3_blob_open(D,...)]
-**          then subsequent calls to [sqlite3_errcode(D)],
-**          [sqlite3_extended_errcode()], 
-**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] shall return
-**          information appropriate for that error.
-**
-** {H17824} If any column in the row that a [sqlite3_blob] has open is
-**          changed by a separate [UPDATE] or [DELETE] statement or by
-**          an [ON CONFLICT] side effect, then the [sqlite3_blob] shall
-**          be marked as invalid.
+** To avoid a resource leak, every open [BLOB handle] should eventually
+** be released by a call to [sqlite3_blob_close()].
 */
-int sqlite3_blob_open(
+SQLITE_API int sqlite3_blob_open(
   sqlite3*,
   const char *zDb,
   const char *zTable,
@@ -5837,178 +5362,136 @@ int sqlite3_blob_open(
 );
 
 /*
-** CAPI3REF: Close A BLOB Handle {H17830} <S30230>
+** CAPI3REF: Move a BLOB Handle to a New Row
 **
-** Closes an open [BLOB handle].
+** ^This function is used to move an existing blob handle so that it points
+** to a different row of the same database table. ^The new row is identified
+** by the rowid value passed as the second argument. Only the row can be
+** changed. ^The database, table and column on which the blob handle is open
+** remain the same. Moving an existing blob handle to a new row can be
+** faster than closing the existing handle and opening a new one.
 **
-** Closing a BLOB shall cause the current transaction to commit
+** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
+** it must exist and there must be either a blob or text value stored in
+** the nominated column.)^ ^If the new row is not present in the table, or if
+** it does not contain a blob or text value, or if another error occurs, an
+** SQLite error code is returned and the blob handle is considered aborted.
+** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
+** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
+** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
+** always returns zero.
+**
+** ^This function sets the database handle error code and message.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
+
+/*
+** CAPI3REF: Close A BLOB Handle
+**
+** ^Closes an open [BLOB handle].
+**
+** ^Closing a BLOB shall cause the current transaction to commit
 ** if there are no other BLOBs, no pending prepared statements, and the
 ** database connection is in [autocommit mode].
-** If any writes were made to the BLOB, they might be held in cache
-** until the close operation if they will fit. {END}
+** ^If any writes were made to the BLOB, they might be held in cache
+** until the close operation if they will fit.
 **
-** Closing the BLOB often forces the changes
+** ^(Closing the BLOB often forces the changes
 ** out to disk and so if any I/O errors occur, they will likely occur
-** at the time when the BLOB is closed.  {H17833} Any errors that occur during
-** closing are reported as a non-zero return value.
+** at the time when the BLOB is closed.  Any errors that occur during
+** closing are reported as a non-zero return value.)^
 **
-** The BLOB is closed unconditionally.  Even if this routine returns
-** an error code, the BLOB is still closed.
+** ^(The BLOB is closed unconditionally.  Even if this routine returns
+** an error code, the BLOB is still closed.)^
 **
-** INVARIANTS:
-**
-** {H17833} The [sqlite3_blob_close(P)] interface closes an [sqlite3_blob]
-**          object P previously opened using [sqlite3_blob_open()].
-**
-** {H17836} Closing an [sqlite3_blob] object using
-**          [sqlite3_blob_close()] shall cause the current transaction to
-**          commit if there are no other open [sqlite3_blob] objects
-**          or [prepared statements] on the same [database connection] and
-**          the database connection is in [autocommit mode].
-**
-** {H17839} The [sqlite3_blob_close(P)] interfaces shall close the
-**          [sqlite3_blob] object P unconditionally, even if
-**          [sqlite3_blob_close(P)] returns something other than [SQLITE_OK].
+** ^Calling this routine with a null pointer (such as would be returned
+** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
 */
-int sqlite3_blob_close(sqlite3_blob *);
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
 
 /*
-** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230>
+** CAPI3REF: Return The Size Of An Open BLOB
 **
-** Returns the size in bytes of the BLOB accessible via the open
-** []BLOB handle] in its only argument.
+** ^Returns the size in bytes of the BLOB accessible via the 
+** successfully opened [BLOB handle] in its only argument.  ^The
+** incremental blob I/O routines can only read or overwriting existing
+** blob content; they cannot change the size of a blob.
 **
-** INVARIANTS:
-**
-** {H17843} The [sqlite3_blob_bytes(P)] interface returns the size
-**          in bytes of the BLOB that the [sqlite3_blob] object P
-**          refers to.
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
 */
-int sqlite3_blob_bytes(sqlite3_blob *);
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
 
 /*
-** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230>
+** CAPI3REF: Read Data From A BLOB Incrementally
 **
-** This function is used to read data from an open [BLOB handle] into a
+** ^(This function is used to read data from an open [BLOB handle] into a
 ** caller-supplied buffer. N bytes of data are copied into buffer Z
-** from the open BLOB, starting at offset iOffset.
+** from the open BLOB, starting at offset iOffset.)^
 **
-** If offset iOffset is less than N bytes from the end of the BLOB,
-** [SQLITE_ERROR] is returned and no data is read.  If N or iOffset is
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
+** ^The size of the blob (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
 **
-** An attempt to read from an expired [BLOB handle] fails with an
+** ^An attempt to read from an expired [BLOB handle] fails with an
 ** error code of [SQLITE_ABORT].
 **
-** On success, SQLITE_OK is returned.
-** Otherwise, an [error code] or an [extended error code] is returned.
+** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
+** Otherwise, an [error code] or an [extended error code] is returned.)^
 **
-** INVARIANTS:
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
 **
-** {H17853} A successful invocation of [sqlite3_blob_read(P,Z,N,X)] 
-**          shall reads N bytes of data out of the BLOB referenced by
-**          [BLOB handle] P beginning at offset X and store those bytes
-**          into buffer Z.
-**
-** {H17856} In [sqlite3_blob_read(P,Z,N,X)] if the size of the BLOB
-**          is less than N+X bytes, then the function shall leave the
-**          Z buffer unchanged and return [SQLITE_ERROR].
-**
-** {H17859} In [sqlite3_blob_read(P,Z,N,X)] if X or N is less than zero
-**          then the function shall leave the Z buffer unchanged
-**          and return [SQLITE_ERROR].
-**
-** {H17862} The [sqlite3_blob_read(P,Z,N,X)] interface shall return [SQLITE_OK]
-**          if N bytes are successfully read into buffer Z.
-**
-** {H17863} If the [BLOB handle] P is expired and X and N are within bounds
-**          then [sqlite3_blob_read(P,Z,N,X)] shall leave the Z buffer
-**          unchanged and return [SQLITE_ABORT].
-**
-** {H17865} If the requested read could not be completed,
-**          the [sqlite3_blob_read(P,Z,N,X)] interface shall return an
-**          appropriate [error code] or [extended error code].
-**
-** {H17868} If an error occurs during evaluation of [sqlite3_blob_read(P,...)]
-**          then subsequent calls to [sqlite3_errcode(D)],
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] shall return
-**          information appropriate for that error, where D is the
-**          [database connection] that was used to open the [BLOB handle] P.
+** See also: [sqlite3_blob_write()].
 */
-int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
 
 /*
-** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230>
+** CAPI3REF: Write Data Into A BLOB Incrementally
 **
-** This function is used to write data into an open [BLOB handle] from a
-** caller-supplied buffer. N bytes of data are copied from the buffer Z
+** ^This function is used to write data into an open [BLOB handle] from a
+** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
 ** into the open BLOB, starting at offset iOffset.
 **
-** If the [BLOB handle] passed as the first argument was not opened for
+** ^If the [BLOB handle] passed as the first argument was not opened for
 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
 ** this function returns [SQLITE_READONLY].
 **
-** This function may only modify the contents of the BLOB; it is
+** ^This function may only modify the contents of the BLOB; it is
 ** not possible to increase the size of a BLOB using this API.
-** If offset iOffset is less than N bytes from the end of the BLOB,
-** [SQLITE_ERROR] is returned and no data is written.  If N is
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is written.  ^If N is
 ** less than zero [SQLITE_ERROR] is returned and no data is written.
+** The size of the BLOB (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
 **
-** An attempt to write to an expired [BLOB handle] fails with an
-** error code of [SQLITE_ABORT].  Writes to the BLOB that occurred
+** ^An attempt to write to an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
 ** before the [BLOB handle] expired are not rolled back by the
 ** expiration of the handle, though of course those changes might
 ** have been overwritten by the statement that expired the BLOB handle
 ** or by other independent statements.
 **
-** On success, SQLITE_OK is returned.
-** Otherwise, an  [error code] or an [extended error code] is returned.
+** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
+** Otherwise, an  [error code] or an [extended error code] is returned.)^
 **
-** INVARIANTS:
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
 **
-** {H17873} A successful invocation of [sqlite3_blob_write(P,Z,N,X)]
-**          shall write N bytes of data from buffer Z into the BLOB 
-**          referenced by [BLOB handle] P beginning at offset X into
-**          the BLOB.
-**
-** {H17874} In the absence of other overridding changes, the changes
-**          written to a BLOB by [sqlite3_blob_write()] shall
-**          remain in effect after the associated [BLOB handle] expires.
-**
-** {H17875} If the [BLOB handle] P was opened for reading only then
-**          an invocation of [sqlite3_blob_write(P,Z,N,X)] shall leave
-**          the referenced BLOB unchanged and return [SQLITE_READONLY].
-**
-** {H17876} If the size of the BLOB referenced by [BLOB handle] P is
-**          less than N+X bytes then [sqlite3_blob_write(P,Z,N,X)] shall
-**          leave the BLOB unchanged and return [SQLITE_ERROR].
-**
-** {H17877} If the [BLOB handle] P is expired and X and N are within bounds
-**          then [sqlite3_blob_read(P,Z,N,X)] shall leave the BLOB
-**          unchanged and return [SQLITE_ABORT].
-**
-** {H17879} If X or N are less than zero then [sqlite3_blob_write(P,Z,N,X)]
-**          shall leave the BLOB referenced by [BLOB handle] P unchanged
-**          and return [SQLITE_ERROR].
-**
-** {H17882} The [sqlite3_blob_write(P,Z,N,X)] interface shall return
-**          [SQLITE_OK] if N bytes where successfully written into the BLOB.
-**
-** {H17885} If the requested write could not be completed,
-**          the [sqlite3_blob_write(P,Z,N,X)] interface shall return an
-**          appropriate [error code] or [extended error code].
-**
-** {H17888} If an error occurs during evaluation of [sqlite3_blob_write(D,...)]
-**          then subsequent calls to [sqlite3_errcode(D)],
-**          [sqlite3_extended_errcode()],
-**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] shall return
-**          information appropriate for that error.
+** See also: [sqlite3_blob_read()].
 */
-int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
 
 /*
-** CAPI3REF: Virtual File System Objects {H11200} <S20100>
+** CAPI3REF: Virtual File System Objects
 **
 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
 ** that SQLite uses to interact
@@ -6017,57 +5500,31 @@ int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
 ** New VFSes can be registered and existing VFSes can be unregistered.
 ** The following interfaces are provided.
 **
-** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
-** Names are case sensitive.
-** Names are zero-terminated UTF-8 strings.
-** If there is no match, a NULL pointer is returned.
-** If zVfsName is NULL then the default VFS is returned.
+** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
+** ^Names are case sensitive.
+** ^Names are zero-terminated UTF-8 strings.
+** ^If there is no match, a NULL pointer is returned.
+** ^If zVfsName is NULL then the default VFS is returned.
 **
-** New VFSes are registered with sqlite3_vfs_register().
-** Each new VFS becomes the default VFS if the makeDflt flag is set.
-** The same VFS can be registered multiple times without injury.
-** To make an existing VFS into the default VFS, register it again
+** ^New VFSes are registered with sqlite3_vfs_register().
+** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
+** ^The same VFS can be registered multiple times without injury.
+** ^To make an existing VFS into the default VFS, register it again
 ** with the makeDflt flag set.  If two different VFSes with the
 ** same name are registered, the behavior is undefined.  If a
 ** VFS is registered with a name that is NULL or an empty string,
 ** then the behavior is undefined.
 **
-** Unregister a VFS with the sqlite3_vfs_unregister() interface.
-** If the default VFS is unregistered, another VFS is chosen as
-** the default.  The choice for the new VFS is arbitrary.
-**
-** INVARIANTS:
-**
-** {H11203} The [sqlite3_vfs_find(N)] interface returns a pointer to the
-**          registered [sqlite3_vfs] object whose name exactly matches
-**          the zero-terminated UTF-8 string N, or it returns NULL if
-**          there is no match.
-**
-** {H11206} If the N parameter to [sqlite3_vfs_find(N)] is NULL then
-**          the function returns a pointer to the default [sqlite3_vfs]
-**          object if there is one, or NULL if there is no default
-**          [sqlite3_vfs] object.
-**
-** {H11209} The [sqlite3_vfs_register(P,F)] interface registers the
-**          well-formed [sqlite3_vfs] object P using the name given
-**          by the zName field of the object.
-**
-** {H11212} Using the [sqlite3_vfs_register(P,F)] interface to register
-**          the same [sqlite3_vfs] object multiple times is a harmless no-op.
-**
-** {H11215} The [sqlite3_vfs_register(P,F)] interface makes the [sqlite3_vfs]
-**          object P the default [sqlite3_vfs] object if F is non-zero.
-**
-** {H11218} The [sqlite3_vfs_unregister(P)] interface unregisters the
-**          [sqlite3_vfs] object P so that it is no longer returned by
-**          subsequent calls to [sqlite3_vfs_find()].
+** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
+** ^(If the default VFS is unregistered, another VFS is chosen as
+** the default.  The choice for the new VFS is arbitrary.)^
 */
-sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
-int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
-int sqlite3_vfs_unregister(sqlite3_vfs*);
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
 
 /*
-** CAPI3REF: Mutexes {H17000} <S20000>
+** CAPI3REF: Mutexes
 **
 ** The SQLite core uses these routines for thread
 ** synchronization. Though they are intended for internal
@@ -6076,34 +5533,33 @@ int sqlite3_vfs_unregister(sqlite3_vfs*);
 **
 ** The SQLite source code contains multiple implementations
 ** of these mutex routines.  An appropriate implementation
-** is selected automatically at compile-time.  The following
+** is selected automatically at compile-time.  ^(The following
 ** implementations are available in the SQLite core:
 **
 ** <ul>
-** <li>   SQLITE_MUTEX_OS2
-** <li>   SQLITE_MUTEX_PTHREAD
+** <li>   SQLITE_MUTEX_PTHREADS
 ** <li>   SQLITE_MUTEX_W32
 ** <li>   SQLITE_MUTEX_NOOP
-** </ul>
+** </ul>)^
 **
-** The SQLITE_MUTEX_NOOP implementation is a set of routines
+** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
 ** that does no real locking and is appropriate for use in
-** a single-threaded application.  The SQLITE_MUTEX_OS2,
-** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
-** are appropriate for use on OS/2, Unix, and Windows.
+** a single-threaded application.  ^The SQLITE_MUTEX_PTHREADS and
+** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
+** and Windows.
 **
-** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
+** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
 ** implementation is included with the library. In this case the
 ** application must supply a custom mutex implementation using the
 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
 ** before calling sqlite3_initialize() or any other public sqlite3_
-** function that calls sqlite3_initialize().
+** function that calls sqlite3_initialize().)^
 **
-** {H17011} The sqlite3_mutex_alloc() routine allocates a new
-** mutex and returns a pointer to it. {H17012} If it returns NULL
-** that means that a mutex could not be allocated. {H17013} SQLite
-** will unwind its stack and return an error. {H17014} The argument
+** ^The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it. ^If it returns NULL
+** that means that a mutex could not be allocated.  ^SQLite
+** will unwind its stack and return an error.  ^(The argument
 ** to sqlite3_mutex_alloc() is one of these integer constants:
 **
 ** <ul>
@@ -6115,78 +5571,79 @@ int sqlite3_vfs_unregister(sqlite3_vfs*);
 ** <li>  SQLITE_MUTEX_STATIC_PRNG
 ** <li>  SQLITE_MUTEX_STATIC_LRU
 ** <li>  SQLITE_MUTEX_STATIC_LRU2
-** </ul>
+** </ul>)^
 **
-** {H17015} The first two constants cause sqlite3_mutex_alloc() to create
-** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
-** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
+** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
+** cause sqlite3_mutex_alloc() to create
+** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
 ** The mutex implementation does not need to make a distinction
 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
-** not want to.  {H17016} But SQLite will only request a recursive mutex in
-** cases where it really needs one.  {END} If a faster non-recursive mutex
+** not want to.  ^SQLite will only request a recursive mutex in
+** cases where it really needs one.  ^If a faster non-recursive mutex
 ** implementation is available on the host platform, the mutex subsystem
 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
 **
-** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return
-** a pointer to a static preexisting mutex. {END}  Four static mutexes are
+** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
+** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
+** a pointer to a static preexisting mutex.  ^Six static mutexes are
 ** used by the current version of SQLite.  Future versions of SQLite
 ** may add additional static mutexes.  Static mutexes are for internal
 ** use by SQLite only.  Applications that use SQLite mutexes should
 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
 ** SQLITE_MUTEX_RECURSIVE.
 **
-** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
-** returns a different mutex on every call.  {H17034} But for the static
+** returns a different mutex on every call.  ^But for the static
 ** mutex types, the same mutex is returned on every call that has
 ** the same type number.
 **
-** {H17019} The sqlite3_mutex_free() routine deallocates a previously
-** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every
-** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in
-** use when they are deallocated. {A17022} Attempting to deallocate a static
-** mutex results in undefined behavior. {H17023} SQLite never deallocates
-** a static mutex. {END}
+** ^The sqlite3_mutex_free() routine deallocates a previously
+** allocated dynamic mutex.  ^SQLite is careful to deallocate every
+** dynamic mutex that it allocates.  The dynamic mutexes must not be in
+** use when they are deallocated.  Attempting to deallocate a static
+** mutex results in undefined behavior.  ^SQLite never deallocates
+** a static mutex.
 **
-** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
-** to enter a mutex. {H17024} If another thread is already within the mutex,
+** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  ^If another thread is already within the mutex,
 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
-** SQLITE_BUSY. {H17025}  The sqlite3_mutex_try() interface returns [SQLITE_OK]
-** upon successful entry.  {H17026} Mutexes created using
+** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
+** upon successful entry.  ^(Mutexes created using
 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
-** {H17027} In such cases the,
+** In such cases the,
 ** mutex must be exited an equal number of times before another thread
-** can enter.  {A17028} If the same thread tries to enter any other
+** can enter.)^  ^(If the same thread tries to enter any other
 ** kind of mutex more than once, the behavior is undefined.
-** {H17029} SQLite will never exhibit
-** such behavior in its own use of mutexes.
+** SQLite will never exhibit
+** such behavior in its own use of mutexes.)^
 **
-** Some systems (for example, Windows 95) do not support the operation
+** ^(Some systems (for example, Windows 95) do not support the operation
 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
-** will always return SQLITE_BUSY.  {H17030} The SQLite core only ever uses
-** sqlite3_mutex_try() as an optimization so this is acceptable behavior.
+** will always return SQLITE_BUSY.  The SQLite core only ever uses
+** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
 **
-** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was
-** previously entered by the same thread.  {A17032} The behavior
+** ^The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.   ^(The behavior
 ** is undefined if the mutex is not currently entered by the
-** calling thread or is not currently allocated.  {H17033} SQLite will
-** never do either. {END}
+** calling thread or is not currently allocated.  SQLite will
+** never do either.)^
 **
-** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
+** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
 ** behave as no-ops.
 **
 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
 */
-sqlite3_mutex *sqlite3_mutex_alloc(int);
-void sqlite3_mutex_free(sqlite3_mutex*);
-void sqlite3_mutex_enter(sqlite3_mutex*);
-int sqlite3_mutex_try(sqlite3_mutex*);
-void sqlite3_mutex_leave(sqlite3_mutex*);
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
 
 /*
-** CAPI3REF: Mutex Methods Object {H17120} <S20130>
-** EXPERIMENTAL
+** CAPI3REF: Mutex Methods Object
 **
 ** An instance of this structure defines the low-level routines
 ** used to allocate and use mutexes.
@@ -6201,19 +5658,19 @@ void sqlite3_mutex_leave(sqlite3_mutex*);
 ** output variable when querying the system for the current mutex
 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
 **
-** The xMutexInit method defined by this structure is invoked as
+** ^The xMutexInit method defined by this structure is invoked as
 ** part of system initialization by the sqlite3_initialize() function.
-** {H17001} The xMutexInit routine shall be called by SQLite once for each
+** ^The xMutexInit routine is called by SQLite exactly once for each
 ** effective call to [sqlite3_initialize()].
 **
-** The xMutexEnd method defined by this structure is invoked as
+** ^The xMutexEnd method defined by this structure is invoked as
 ** part of system shutdown by the sqlite3_shutdown() function. The
 ** implementation of this method is expected to release all outstanding
 ** resources obtained by the mutex methods implementation, especially
-** those obtained by the xMutexInit method. {H17003} The xMutexEnd()
-** interface shall be invoked once for each call to [sqlite3_shutdown()].
+** those obtained by the xMutexInit method.  ^The xMutexEnd()
+** interface is invoked exactly once for each call to [sqlite3_shutdown()].
 **
-** The remaining seven methods defined by this structure (xMutexAlloc,
+** ^(The remaining seven methods defined by this structure (xMutexAlloc,
 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
 ** xMutexNotheld) implement the following interfaces (respectively):
 **
@@ -6225,7 +5682,7 @@ void sqlite3_mutex_leave(sqlite3_mutex*);
 **   <li>  [sqlite3_mutex_leave()] </li>
 **   <li>  [sqlite3_mutex_held()] </li>
 **   <li>  [sqlite3_mutex_notheld()] </li>
-** </ul>
+** </ul>)^
 **
 ** The only difference is that the public sqlite3_XXX functions enumerated
 ** above silently ignore any invocations that pass a NULL pointer instead
@@ -6234,6 +5691,21 @@ void sqlite3_mutex_leave(sqlite3_mutex*);
 ** of passing a NULL pointer instead of a valid mutex handle are undefined
 ** (i.e. it is acceptable to provide an implementation that segfaults if
 ** it is passed a NULL pointer).
+**
+** The xMutexInit() method must be threadsafe.  ^It must be harmless to
+** invoke xMutexInit() multiple times within the same process and without
+** intervening calls to xMutexEnd().  Second and subsequent calls to
+** xMutexInit() must be no-ops.
+**
+** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
+** and its associates).  ^Similarly, xMutexAlloc() must not use SQLite memory
+** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
+** memory allocation for a fast or recursive mutex.
+**
+** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
+** called, but only if the prior call to xMutexInit returned SQLITE_OK.
+** If xMutexInit fails in any way, it is expected to clean up after itself
+** prior to returning.
 */
 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
 struct sqlite3_mutex_methods {
@@ -6249,39 +5721,41 @@ struct sqlite3_mutex_methods {
 };
 
 /*
-** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800>
+** CAPI3REF: Mutex Verification Routines
 **
 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
-** are intended for use inside assert() statements. {H17081} The SQLite core
+** are intended for use inside assert() statements.  ^The SQLite core
 ** never uses these routines except inside an assert() and applications
-** are advised to follow the lead of the core.  {H17082} The core only
+** are advised to follow the lead of the core.  ^The SQLite core only
 ** provides implementations for these routines when it is compiled
-** with the SQLITE_DEBUG flag.  {A17087} External mutex implementations
+** with the SQLITE_DEBUG flag.  ^External mutex implementations
 ** are only required to provide these routines if SQLITE_DEBUG is
 ** defined and if NDEBUG is not defined.
 **
-** {H17083} These routines should return true if the mutex in their argument
+** ^These routines should return true if the mutex in their argument
 ** is held or not held, respectively, by the calling thread.
 **
-** {X17084} The implementation is not required to provided versions of these
+** ^The implementation is not required to provide versions of these
 ** routines that actually work. If the implementation does not provide working
 ** versions of these routines, it should at least provide stubs that always
 ** return true so that one does not get spurious assertion failures.
 **
-** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then
-** the routine should return 1.  {END} This seems counter-intuitive since
-** clearly the mutex cannot be held if it does not exist.  But the
+** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
+** the routine should return 1.   This seems counter-intuitive since
+** clearly the mutex cannot be held if it does not exist.  But
 ** the reason the mutex does not exist is because the build is not
 ** using mutexes.  And we do not want the assert() containing the
 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
-** the appropriate thing to do.  {H17086} The sqlite3_mutex_notheld()
+** the appropriate thing to do.  ^The sqlite3_mutex_notheld()
 ** interface should also return 1 when given a NULL pointer.
 */
-int sqlite3_mutex_held(sqlite3_mutex*);
-int sqlite3_mutex_notheld(sqlite3_mutex*);
+#ifndef NDEBUG
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
+#endif
 
 /*
-** CAPI3REF: Mutex Types {H17001} <H17000>
+** CAPI3REF: Mutex Types
 **
 ** The [sqlite3_mutex_alloc()] interface takes a single argument
 ** which is one of these integer constants.
@@ -6294,54 +5768,64 @@ int sqlite3_mutex_notheld(sqlite3_mutex*);
 #define SQLITE_MUTEX_RECURSIVE        1
 #define SQLITE_MUTEX_STATIC_MASTER    2
 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
-#define SQLITE_MUTEX_STATIC_MEM2      4  /* sqlite3_release_memory() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
-#define SQLITE_MUTEX_STATIC_LRU2      7  /* lru page list */
+#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
 
 /*
-** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000>
+** CAPI3REF: Retrieve the mutex for a database connection
 **
-** This interface returns a pointer the [sqlite3_mutex] object that 
+** ^This interface returns a pointer the [sqlite3_mutex] object that 
 ** serializes access to the [database connection] given in the argument
 ** when the [threading mode] is Serialized.
-** If the [threading mode] is Single-thread or Multi-thread then this
+** ^If the [threading mode] is Single-thread or Multi-thread then this
 ** routine returns a NULL pointer.
 */
-sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
+SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
 
 /*
-** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800>
+** CAPI3REF: Low-Level Control Of Database Files
 **
-** {H11301} The [sqlite3_file_control()] interface makes a direct call to the
+** ^The [sqlite3_file_control()] interface makes a direct call to the
 ** xFileControl method for the [sqlite3_io_methods] object associated
-** with a particular database identified by the second argument. {H11302} The
-** name of the database is the name assigned to the database by the
-** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
-** database. {H11303} To control the main database file, use the name "main"
-** or a NULL pointer. {H11304} The third and fourth parameters to this routine
+** with a particular database identified by the second argument. ^The
+** name of the database is "main" for the main database or "temp" for the
+** TEMP database, or the name that appears after the AS keyword for
+** databases that are added using the [ATTACH] SQL command.
+** ^A NULL pointer can be used in place of "main" to refer to the
+** main database file.
+** ^The third and fourth parameters to this routine
 ** are passed directly through to the second and third parameters of
-** the xFileControl method.  {H11305} The return value of the xFileControl
+** the xFileControl method.  ^The return value of the xFileControl
 ** method becomes the return value of this routine.
 **
-** {H11306} If the second parameter (zDbName) does not match the name of any
-** open database file, then SQLITE_ERROR is returned. {H11307} This error
+** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
+** a pointer to the underlying [sqlite3_file] object to be written into
+** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
+** case is a short-circuit path which does not actually invoke the
+** underlying sqlite3_io_methods.xFileControl method.
+**
+** ^If the second parameter (zDbName) does not match the name of any
+** open database file, then SQLITE_ERROR is returned.  ^This error
 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
-** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might
-** also return SQLITE_ERROR.  {A11309} There is no way to distinguish between
+** or [sqlite3_errmsg()].  The underlying xFileControl method might
+** also return SQLITE_ERROR.  There is no way to distinguish between
 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
-** xFileControl method. {END}
+** xFileControl method.
 **
 ** See also: [SQLITE_FCNTL_LOCKSTATE]
 */
-int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
+SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
 
 /*
-** CAPI3REF: Testing Interface {H11400} <S30800>
+** CAPI3REF: Testing Interface
 **
-** The sqlite3_test_control() interface is used to read out internal
+** ^The sqlite3_test_control() interface is used to read out internal
 ** state of SQLite and to inject faults into SQLite for testing
-** purposes.  The first parameter is an operation code that determines
+** purposes.  ^The first parameter is an operation code that determines
 ** the number, meaning, and operation of all subsequent parameters.
 **
 ** This interface is not for use by applications.  It exists solely
@@ -6353,10 +5837,10 @@ int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
 ** Unlike most of the SQLite API, this function is not guaranteed to
 ** operate consistently from one release to the next.
 */
-int sqlite3_test_control(int op, ...);
+SQLITE_API int sqlite3_test_control(int op, ...);
 
 /*
-** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400>
+** CAPI3REF: Testing Interface Operation Codes
 **
 ** These constants are the valid operation code parameters used
 ** as the first argument to [sqlite3_test_control()].
@@ -6366,35 +5850,45 @@ int sqlite3_test_control(int op, ...);
 ** Applications should not use any of these parameters or the
 ** [sqlite3_test_control()] interface.
 */
+#define SQLITE_TESTCTRL_FIRST                    5
 #define SQLITE_TESTCTRL_PRNG_SAVE                5
 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
 #define SQLITE_TESTCTRL_PRNG_RESET               7
 #define SQLITE_TESTCTRL_BITVEC_TEST              8
 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
+#define SQLITE_TESTCTRL_PENDING_BYTE            11
+#define SQLITE_TESTCTRL_ASSERT                  12
+#define SQLITE_TESTCTRL_ALWAYS                  13
+#define SQLITE_TESTCTRL_RESERVE                 14
+#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
+#define SQLITE_TESTCTRL_ISKEYWORD               16
+#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
+#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
+#define SQLITE_TESTCTRL_EXPLAIN_STMT            19
+#define SQLITE_TESTCTRL_LAST                    19
 
 /*
-** CAPI3REF: SQLite Runtime Status {H17200} <S60200>
-** EXPERIMENTAL
+** CAPI3REF: SQLite Runtime Status
 **
-** This interface is used to retrieve runtime status information
-** about the preformance of SQLite, and optionally to reset various
-** highwater marks.  The first argument is an integer code for
-** the specific parameter to measure.  Recognized integer codes
-** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].
-** The current value of the parameter is returned into *pCurrent.
-** The highest recorded value is returned in *pHighwater.  If the
+** ^This interface is used to retrieve runtime status information
+** about the performance of SQLite, and optionally to reset various
+** highwater marks.  ^The first argument is an integer code for
+** the specific parameter to measure.  ^(Recognized integer codes
+** are of the form [status parameters | SQLITE_STATUS_...].)^
+** ^The current value of the parameter is returned into *pCurrent.
+** ^The highest recorded value is returned in *pHighwater.  ^If the
 ** resetFlag is true, then the highest record value is reset after
-** *pHighwater is written. Some parameters do not record the highest
+** *pHighwater is written.  ^(Some parameters do not record the highest
 ** value.  For those parameters
-** nothing is written into *pHighwater and the resetFlag is ignored.
-** Other parameters record only the highwater mark and not the current
-** value.  For these latter parameters nothing is written into *pCurrent.
+** nothing is written into *pHighwater and the resetFlag is ignored.)^
+** ^(Other parameters record only the highwater mark and not the current
+** value.  For these latter parameters nothing is written into *pCurrent.)^
 **
-** This routine returns SQLITE_OK on success and a non-zero
-** [error code] on failure.
+** ^The sqlite3_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
 **
-** This routine is threadsafe but is not atomic.  This routine can
+** This routine is threadsafe but is not atomic.  This routine can be
 ** called while other threads are running the same or different SQLite
 ** interfaces.  However the values returned in *pCurrent and
 ** *pHighwater reflect the status of SQLite at different points in time
@@ -6403,18 +5897,18 @@ int sqlite3_test_control(int op, ...);
 **
 ** See also: [sqlite3_db_status()]
 */
-SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
 
 
 /*
-** CAPI3REF: Status Parameters {H17250} <H17200>
-** EXPERIMENTAL
+** CAPI3REF: Status Parameters
+** KEYWORDS: {status parameters}
 **
 ** These integer constants designate various run-time status parameters
 ** that can be returned by [sqlite3_status()].
 **
 ** <dl>
-** <dt>SQLITE_STATUS_MEMORY_USED</dt>
+** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
 ** <dd>This parameter is the current amount of memory checked out
 ** using [sqlite3_malloc()], either directly or indirectly.  The
 ** figure includes calls made to [sqlite3_malloc()] by the application
@@ -6422,63 +5916,68 @@ SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, i
 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
 ** this parameter.  The amount returned is the sum of the allocation
-** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>
+** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
 **
-** <dt>SQLITE_STATUS_MALLOC_SIZE</dt>
+** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
 ** internal equivalents).  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
-** The value written into the *pCurrent parameter is undefined.</dd>
+** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
-** <dt>SQLITE_STATUS_PAGECACHE_USED</dt>
+** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
+** <dd>This parameter records the number of separate memory allocations
+** currently checked out.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
 ** <dd>This parameter returns the number of pages used out of the
 ** [pagecache memory allocator] that was configured using 
 ** [SQLITE_CONFIG_PAGECACHE].  The
-** value returned is in pages, not in bytes.</dd>
+** value returned is in pages, not in bytes.</dd>)^
 **
-** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
+** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 
+** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
 ** <dd>This parameter returns the number of bytes of page cache
-** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE]
+** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
 ** returned value includes allocations that overflowed because they
 ** where too large (they were larger than the "sz" parameter to
 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
-** no space was left in the page cache.</dd>
+** no space was left in the page cache.</dd>)^
 **
-** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
+** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [pagecache memory allocator].  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
-** The value written into the *pCurrent parameter is undefined.</dd>
+** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
-** <dt>SQLITE_STATUS_SCRATCH_USED</dt>
+** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
 ** <dd>This parameter returns the number of allocations used out of the
 ** [scratch memory allocator] configured using
 ** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
 ** in bytes.  Since a single thread may only have one scratch allocation
 ** outstanding at time, this parameter also reports the number of threads
-** using scratch memory at the same time.</dd>
+** using scratch memory at the same time.</dd>)^
 **
-** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
+** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
 ** <dd>This parameter returns the number of bytes of scratch memory
-** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH]
+** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
 ** buffer and where forced to overflow to [sqlite3_malloc()].  The values
 ** returned include overflows because the requested allocation was too
 ** larger (that is, because the requested allocation was larger than the
 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
 ** slots were available.
-** </dd>
+** </dd>)^
 **
-** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
+** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [scratch memory allocator].  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
-** The value written into the *pCurrent parameter is undefined.</dd>
+** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
-** <dt>SQLITE_STATUS_PARSER_STACK</dt>
+** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
 ** <dd>This parameter records the deepest parser stack.  It is only
-** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>
+** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
 ** </dl>
 **
 ** New status parameters may be added from time to time.
@@ -6492,96 +5991,188 @@ SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, i
 #define SQLITE_STATUS_PARSER_STACK         6
 #define SQLITE_STATUS_PAGECACHE_SIZE       7
 #define SQLITE_STATUS_SCRATCH_SIZE         8
+#define SQLITE_STATUS_MALLOC_COUNT         9
 
 /*
-** CAPI3REF: Database Connection Status {H17500} <S60200>
-** EXPERIMENTAL
+** CAPI3REF: Database Connection Status
 **
-** This interface is used to retrieve runtime status information 
-** about a single [database connection].  The first argument is the
-** database connection object to be interrogated.  The second argument
-** is the parameter to interrogate.  Currently, the only allowed value
-** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED].
-** Additional options will likely appear in future releases of SQLite.
+** ^This interface is used to retrieve runtime status information 
+** about a single [database connection].  ^The first argument is the
+** database connection object to be interrogated.  ^The second argument
+** is an integer constant, taken from the set of
+** [SQLITE_DBSTATUS options], that
+** determines the parameter to interrogate.  The set of 
+** [SQLITE_DBSTATUS options] is likely
+** to grow in future releases of SQLite.
 **
-** The current value of the requested parameter is written into *pCur
-** and the highest instantaneous value is written into *pHiwtr.  If
+** ^The current value of the requested parameter is written into *pCur
+** and the highest instantaneous value is written into *pHiwtr.  ^If
 ** the resetFlg is true, then the highest instantaneous value is
 ** reset back down to the current value.
 **
+** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
+**
 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
 */
-SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
+SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
 
 /*
-** CAPI3REF: Status Parameters for database connections {H17520} <H17500>
-** EXPERIMENTAL
+** CAPI3REF: Status Parameters for database connections
+** KEYWORDS: {SQLITE_DBSTATUS options}
 **
-** Status verbs for [sqlite3_db_status()].
+** These constants are the available integer "verbs" that can be passed as
+** the second argument to the [sqlite3_db_status()] interface.
+**
+** New verbs may be added in future releases of SQLite. Existing verbs
+** might be discontinued. Applications should check the return code from
+** [sqlite3_db_status()] to make sure that the call worked.
+** The [sqlite3_db_status()] interface will return a non-zero error code
+** if a discontinued or unsupported verb is invoked.
 **
 ** <dl>
-** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
+** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
 ** <dd>This parameter returns the number of lookaside memory slots currently
-** checked out.</dd>
+** checked out.</dd>)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
+** <dd>This parameter returns the number malloc attempts that were 
+** satisfied using lookaside memory. Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to the amount of
+** memory requested being larger than the lookaside slot size.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to all lookaside
+** memory already being in use.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
+** <dd>This parameter returns the approximate number of of bytes of heap
+** memory used by all pager caches associated with the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
+** <dd>This parameter returns the approximate number of of bytes of heap
+** memory used to store the schema for all databases associated
+** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 
+** ^The full amount of memory used by the schemas is reported, even if the
+** schema memory is shared with other database connections due to
+** [shared cache mode] being enabled.
+** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
+** <dd>This parameter returns the approximate number of of bytes of heap
+** and lookaside memory used by all prepared statements associated with
+** the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
+** <dd>This parameter returns the number of pager cache hits that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
+** <dd>This parameter returns the number of pager cache misses that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk. Specifically, the number of pages written to the
+** wal file in wal mode databases, or the number of pages written to the
+** database file in rollback mode databases. Any pages written as part of
+** transaction rollback or database recovery operations are not included.
+** If an IO or other error occurs while writing a page to disk, the effect
+** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
+** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
+** </dd>
 ** </dl>
 */
-#define SQLITE_DBSTATUS_LOOKASIDE_USED     0
+#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
+#define SQLITE_DBSTATUS_CACHE_USED           1
+#define SQLITE_DBSTATUS_SCHEMA_USED          2
+#define SQLITE_DBSTATUS_STMT_USED            3
+#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
+#define SQLITE_DBSTATUS_CACHE_HIT            7
+#define SQLITE_DBSTATUS_CACHE_MISS           8
+#define SQLITE_DBSTATUS_CACHE_WRITE          9
+#define SQLITE_DBSTATUS_MAX                  9   /* Largest defined DBSTATUS */
 
 
 /*
-** CAPI3REF: Prepared Statement Status {H17550} <S60200>
-** EXPERIMENTAL
+** CAPI3REF: Prepared Statement Status
 **
-** Each prepared statement maintains various
-** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
-** of times it has performed specific operations.  These counters can
+** ^(Each prepared statement maintains various
+** [SQLITE_STMTSTATUS counters] that measure the number
+** of times it has performed specific operations.)^  These counters can
 ** be used to monitor the performance characteristics of the prepared
 ** statements.  For example, if the number of table steps greatly exceeds
 ** the number of table searches or result rows, that would tend to indicate
 ** that the prepared statement is using a full table scan rather than
 ** an index.  
 **
-** This interface is used to retrieve and reset counter values from
+** ^(This interface is used to retrieve and reset counter values from
 ** a [prepared statement].  The first argument is the prepared statement
 ** object to be interrogated.  The second argument
-** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
-** to be interrogated. 
-** The current value of the requested counter is returned.
-** If the resetFlg is true, then the counter is reset to zero after this
+** is an integer code for a specific [SQLITE_STMTSTATUS counter]
+** to be interrogated.)^
+** ^The current value of the requested counter is returned.
+** ^If the resetFlg is true, then the counter is reset to zero after this
 ** interface call returns.
 **
 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
 */
-SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
 
 /*
-** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550>
-** EXPERIMENTAL
+** CAPI3REF: Status Parameters for prepared statements
+** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
 **
 ** These preprocessor macros define integer codes that name counter
 ** values associated with the [sqlite3_stmt_status()] interface.
 ** The meanings of the various counters are as follows:
 **
 ** <dl>
-** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
-** <dd>This is the number of times that SQLite has stepped forward in
+** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
+** <dd>^This is the number of times that SQLite has stepped forward in
 ** a table as part of a full table scan.  Large numbers for this counter
 ** may indicate opportunities for performance improvement through 
 ** careful use of indices.</dd>
 **
-** <dt>SQLITE_STMTSTATUS_SORT</dt>
-** <dd>This is the number of sort operations that have occurred.
+** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
+** <dd>^This is the number of sort operations that have occurred.
 ** A non-zero value in this counter may indicate an opportunity to
 ** improvement performance through careful use of indices.</dd>
 **
+** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
+** <dd>^This is the number of rows inserted into transient indices that
+** were created automatically in order to help joins run faster.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance by adding permanent indices that do not
+** need to be reinitialized each time the statement is run.</dd>
 ** </dl>
 */
 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
 #define SQLITE_STMTSTATUS_SORT              2
+#define SQLITE_STMTSTATUS_AUTOINDEX         3
 
 /*
 ** CAPI3REF: Custom Page Cache Object
-** EXPERIMENTAL
 **
 ** The sqlite3_pcache type is opaque.  It is implemented by
 ** the pluggable module.  The SQLite core has no knowledge of
@@ -6589,110 +6180,164 @@ SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
 ** sqlite3_pcache object except by holding and passing pointers
 ** to the object.
 **
-** See [sqlite3_pcache_methods] for additional information.
+** See [sqlite3_pcache_methods2] for additional information.
 */
 typedef struct sqlite3_pcache sqlite3_pcache;
 
 /*
-** CAPI3REF: Application Defined Page Cache.
-** EXPERIMENTAL
+** CAPI3REF: Custom Page Cache Object
 **
-** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
+** The sqlite3_pcache_page object represents a single page in the
+** page cache.  The page cache will allocate instances of this
+** object.  Various methods of the page cache use pointers to instances
+** of this object as parameters or as their return value.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache_page sqlite3_pcache_page;
+struct sqlite3_pcache_page {
+  void *pBuf;        /* The content of the page */
+  void *pExtra;      /* Extra information associated with the page */
+};
+
+/*
+** CAPI3REF: Application Defined Page Cache.
+** KEYWORDS: {page cache}
+**
+** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
 ** register an alternative page cache implementation by passing in an 
-** instance of the sqlite3_pcache_methods structure. The majority of the 
-** heap memory used by sqlite is used by the page cache to cache data read 
-** from, or ready to be written to, the database file. By implementing a 
-** custom page cache using this API, an application can control more 
-** precisely the amount of memory consumed by sqlite, the way in which 
-** said memory is allocated and released, and the policies used to 
+** instance of the sqlite3_pcache_methods2 structure.)^
+** In many applications, most of the heap memory allocated by 
+** SQLite is used for the page cache.
+** By implementing a 
+** custom page cache using this API, an application can better control
+** the amount of memory consumed by SQLite, the way in which 
+** that memory is allocated and released, and the policies used to 
 ** determine exactly which parts of a database file are cached and for 
 ** how long.
 **
-** The contents of the structure are copied to an internal buffer by sqlite
-** within the call to [sqlite3_config].
+** The alternative page cache mechanism is an
+** extreme measure that is only needed by the most demanding applications.
+** The built-in page cache is recommended for most uses.
 **
-** The xInit() method is called once for each call to [sqlite3_initialize()]
-** (usually only once during the lifetime of the process). It is passed
-** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set
-** up global structures and mutexes required by the custom page cache 
-** implementation. The xShutdown() method is called from within 
-** [sqlite3_shutdown()], if the application invokes this API. It can be used
-** to clean up any outstanding resources before process shutdown, if required.
+** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
+** internal buffer by SQLite within the call to [sqlite3_config].  Hence
+** the application may discard the parameter after the call to
+** [sqlite3_config()] returns.)^
 **
-** The xCreate() method is used to construct a new cache instance. The
+** [[the xInit() page cache method]]
+** ^(The xInit() method is called once for each effective 
+** call to [sqlite3_initialize()])^
+** (usually only once during the lifetime of the process). ^(The xInit()
+** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
+** The intent of the xInit() method is to set up global data structures 
+** required by the custom page cache implementation. 
+** ^(If the xInit() method is NULL, then the 
+** built-in default page cache is used instead of the application defined
+** page cache.)^
+**
+** [[the xShutdown() page cache method]]
+** ^The xShutdown() method is called by [sqlite3_shutdown()].
+** It can be used to clean up 
+** any outstanding resources before process shutdown, if required.
+** ^The xShutdown() method may be NULL.
+**
+** ^SQLite automatically serializes calls to the xInit method,
+** so the xInit method need not be threadsafe.  ^The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  All other methods must be threadsafe
+** in multithreaded applications.
+**
+** ^SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+**
+** [[the xCreate() page cache methods]]
+** ^SQLite invokes the xCreate() method to construct a new cache instance.
+** SQLite will typically create one cache instance for each open database file,
+** though this is not guaranteed. ^The
 ** first parameter, szPage, is the size in bytes of the pages that must
-** be allocated by the cache. szPage will not be a power of two. The
-** second argument, bPurgeable, is true if the cache being created will
-** be used to cache database pages read from a file stored on disk, or
+** be allocated by the cache.  ^szPage will always a power of two.  ^The
+** second parameter szExtra is a number of bytes of extra storage 
+** associated with each page cache entry.  ^The szExtra parameter will
+** a number less than 250.  SQLite will use the
+** extra szExtra bytes on each page to store metadata about the underlying
+** database page on disk.  The value passed into szExtra depends
+** on the SQLite version, the target platform, and how SQLite was compiled.
+** ^The third argument to xCreate(), bPurgeable, is true if the cache being
+** created will be used to cache database pages of a file stored on disk, or
 ** false if it is used for an in-memory database. The cache implementation
-** does not have to do anything special based on the value of bPurgeable,
-** it is purely advisory. 
+** does not have to do anything special based with the value of bPurgeable;
+** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
+** never invoke xUnpin() except to deliberately delete a page.
+** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
+** false will always have the "discard" flag set to true.  
+** ^Hence, a cache created with bPurgeable false will
+** never contain any unpinned pages.
 **
-** The xCachesize() method may be called at any time by SQLite to set the
+** [[the xCachesize() page cache method]]
+** ^(The xCachesize() method may be called at any time by SQLite to set the
 ** suggested maximum cache-size (number of pages stored by) the cache
 ** instance passed as the first argument. This is the value configured using
-** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter,
-** the implementation is not required to do anything special with this
-** value, it is advisory only.
+** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
+** parameter, the implementation is not required to do anything with this
+** value; it is advisory only.
 **
-** The xPagecount() method should return the number of pages currently
-** stored in the cache supplied as an argument.
+** [[the xPagecount() page cache methods]]
+** The xPagecount() method must return the number of pages currently
+** stored in the cache, both pinned and unpinned.
 ** 
-** The xFetch() method is used to fetch a page and return a pointer to it. 
-** A 'page', in this context, is a buffer of szPage bytes aligned at an
-** 8-byte boundary. The page to be fetched is determined by the key. The
-** mimimum key value is 1. After it has been retrieved using xFetch, the page 
-** is considered to be pinned.
+** [[the xFetch() page cache methods]]
+** The xFetch() method locates a page in the cache and returns a pointer to 
+** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
+** The pBuf element of the returned sqlite3_pcache_page object will be a
+** pointer to a buffer of szPage bytes used to store the content of a 
+** single database page.  The pExtra element of sqlite3_pcache_page will be
+** a pointer to the szExtra bytes of extra storage that SQLite has requested
+** for each entry in the page cache.
 **
-** If the requested page is already in the page cache, then a pointer to
-** the cached buffer should be returned with its contents intact. If the
-** page is not already in the cache, then the expected behaviour of the
-** cache is determined by the value of the createFlag parameter passed
-** to xFetch, according to the following table:
+** The page to be fetched is determined by the key. ^The minimum key value
+** is 1.  After it has been retrieved using xFetch, the page is considered
+** to be "pinned".
+**
+** If the requested page is already in the page cache, then the page cache
+** implementation must return a pointer to the page buffer with its content
+** intact.  If the requested page is not already in the cache, then the
+** cache implementation should use the value of the createFlag
+** parameter to help it determined what action to take:
 **
 ** <table border=1 width=85% align=center>
-**   <tr><th>createFlag<th>Expected Behaviour
-**   <tr><td>0<td>NULL should be returned. No new cache entry is created.
-**   <tr><td>1<td>If createFlag is set to 1, this indicates that 
-**                SQLite is holding pinned pages that can be unpinned
-**                by writing their contents to the database file (a
-**                relatively expensive operation). In this situation the
-**                cache implementation has two choices: it can return NULL,
-**                in which case SQLite will attempt to unpin one or more 
-**                pages before re-requesting the same page, or it can
-**                allocate a new page and return a pointer to it. If a new
-**                page is allocated, then it must be completely zeroed before 
-**                it is returned.
-**   <tr><td>2<td>If createFlag is set to 2, then SQLite is not holding any
-**                pinned pages associated with the specific cache passed
-**                as the first argument to xFetch() that can be unpinned. The
-**                cache implementation should attempt to allocate a new
-**                cache entry and return a pointer to it. Again, the new
-**                page should be zeroed before it is returned. If the xFetch()
-**                method returns NULL when createFlag==2, SQLite assumes that
-**                a memory allocation failed and returns SQLITE_NOMEM to the
-**                user.
+** <tr><th> createFlag <th> Behaviour when page is not already in cache
+** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
+** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
+**                 Otherwise return NULL.
+** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
+**                 NULL if allocating a new page is effectively impossible.
 ** </table>
 **
-** xUnpin() is called by SQLite with a pointer to a currently pinned page
-** as its second argument. If the third parameter, discard, is non-zero,
-** then the page should be evicted from the cache. In this case SQLite 
-** assumes that the next time the page is retrieved from the cache using
-** the xFetch() method, it will be zeroed. If the discard parameter is
-** zero, then the page is considered to be unpinned. The cache implementation
-** may choose to reclaim (free or recycle) unpinned pages at any time.
-** SQLite assumes that next time the page is retrieved from the cache
-** it will either be zeroed, or contain the same data that it did when it
-** was unpinned.
+** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
+** will only use a createFlag of 2 after a prior call with a createFlag of 1
+** failed.)^  In between the to xFetch() calls, SQLite may
+** attempt to unpin one or more cache pages by spilling the content of
+** pinned pages to disk and synching the operating system disk cache.
 **
-** The cache is not required to perform any reference counting. A single 
+** [[the xUnpin() page cache method]]
+** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
+** as its second argument.  If the third parameter, discard, is non-zero,
+** then the page must be evicted from the cache.
+** ^If the discard parameter is
+** zero, then the page may be discarded or retained at the discretion of
+** page cache implementation. ^The page cache implementation
+** may choose to evict unpinned pages at any time.
+**
+** The cache must not perform any reference counting. A single 
 ** call to xUnpin() unpins the page regardless of the number of prior calls 
 ** to xFetch().
 **
+** [[the xRekey() page cache methods]]
 ** The xRekey() method is used to change the key value associated with the
-** page passed as the second argument from oldKey to newKey. If the cache
-** previously contains an entry associated with newKey, it should be
-** discarded. Any prior cache entry associated with newKey is guaranteed not
+** page passed as the second argument. If the cache
+** previously contains an entry associated with newKey, it must be
+** discarded. ^Any prior cache entry associated with newKey is guaranteed not
 ** to be pinned.
 **
 ** When SQLite calls the xTruncate() method, the cache must discard all
@@ -6701,11 +6346,41 @@ typedef struct sqlite3_pcache sqlite3_pcache;
 ** of these pages are pinned, they are implicitly unpinned, meaning that
 ** they can be safely discarded.
 **
-** The xDestroy() method is used to delete a cache allocated by xCreate().
-** All resources associated with the specified cache should be freed. After
+** [[the xDestroy() page cache method]]
+** ^The xDestroy() method is used to delete a cache allocated by xCreate().
+** All resources associated with the specified cache should be freed. ^After
 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
-** handle invalid, and will not use it with any other sqlite3_pcache_methods
+** handle invalid, and will not use it with any other sqlite3_pcache_methods2
 ** functions.
+**
+** [[the xShrink() page cache method]]
+** ^SQLite invokes the xShrink() method when it wants the page cache to
+** free up as much of heap memory as possible.  The page cache implementation
+** is not obligated to free any memory, but well-behaved implementations should
+** do their best.
+*/
+typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
+struct sqlite3_pcache_methods2 {
+  int iVersion;
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
+  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 
+      unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+  void (*xShrink)(sqlite3_pcache*);
+};
+
+/*
+** This is the obsolete pcache_methods object that has now been replaced
+** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
+** retained in the header file for backwards compatibility only.
 */
 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
 struct sqlite3_pcache_methods {
@@ -6722,6 +6397,631 @@ struct sqlite3_pcache_methods {
   void (*xDestroy)(sqlite3_pcache*);
 };
 
+
+/*
+** CAPI3REF: Online Backup Object
+**
+** The sqlite3_backup object records state information about an ongoing
+** online backup operation.  ^The sqlite3_backup object is created by
+** a call to [sqlite3_backup_init()] and is destroyed by a call to
+** [sqlite3_backup_finish()].
+**
+** See Also: [Using the SQLite Online Backup API]
+*/
+typedef struct sqlite3_backup sqlite3_backup;
+
+/*
+** CAPI3REF: Online Backup API.
+**
+** The backup API copies the content of one database into another.
+** It is useful either for creating backups of databases or
+** for copying in-memory databases to or from persistent files. 
+**
+** See Also: [Using the SQLite Online Backup API]
+**
+** ^SQLite holds a write transaction open on the destination database file
+** for the duration of the backup operation.
+** ^The source database is read-locked only while it is being read;
+** it is not locked continuously for the entire backup operation.
+** ^Thus, the backup may be performed on a live source database without
+** preventing other database connections from
+** reading or writing to the source database while the backup is underway.
+** 
+** ^(To perform a backup operation: 
+**   <ol>
+**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
+**         backup, 
+**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 
+**         the data between the two databases, and finally
+**     <li><b>sqlite3_backup_finish()</b> is called to release all resources 
+**         associated with the backup operation. 
+**   </ol>)^
+** There should be exactly one call to sqlite3_backup_finish() for each
+** successful call to sqlite3_backup_init().
+**
+** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
+**
+** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 
+** [database connection] associated with the destination database 
+** and the database name, respectively.
+** ^The database name is "main" for the main database, "temp" for the
+** temporary database, or the name specified after the AS keyword in
+** an [ATTACH] statement for an attached database.
+** ^The S and M arguments passed to 
+** sqlite3_backup_init(D,N,S,M) identify the [database connection]
+** and database name of the source database, respectively.
+** ^The source and destination [database connections] (parameters S and D)
+** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
+** an error.
+**
+** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
+** returned and an error code and error message are stored in the
+** destination [database connection] D.
+** ^The error code and message for the failed call to sqlite3_backup_init()
+** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
+** [sqlite3_errmsg16()] functions.
+** ^A successful call to sqlite3_backup_init() returns a pointer to an
+** [sqlite3_backup] object.
+** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
+** sqlite3_backup_finish() functions to perform the specified backup 
+** operation.
+**
+** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
+**
+** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 
+** the source and destination databases specified by [sqlite3_backup] object B.
+** ^If N is negative, all remaining source pages are copied. 
+** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
+** are still more pages to be copied, then the function returns [SQLITE_OK].
+** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
+** from source to destination, then it returns [SQLITE_DONE].
+** ^If an error occurs while running sqlite3_backup_step(B,N),
+** then an [error code] is returned. ^As well as [SQLITE_OK] and
+** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
+** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
+**
+** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
+** <ol>
+** <li> the destination database was opened read-only, or
+** <li> the destination database is using write-ahead-log journaling
+** and the destination and source page sizes differ, or
+** <li> the destination database is an in-memory database and the
+** destination and source page sizes differ.
+** </ol>)^
+**
+** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
+** the [sqlite3_busy_handler | busy-handler function]
+** is invoked (if one is specified). ^If the 
+** busy-handler returns non-zero before the lock is available, then 
+** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
+** sqlite3_backup_step() can be retried later. ^If the source
+** [database connection]
+** is being used to write to the source database when sqlite3_backup_step()
+** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
+** case the call to sqlite3_backup_step() can be retried later on. ^(If
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
+** [SQLITE_READONLY] is returned, then 
+** there is no point in retrying the call to sqlite3_backup_step(). These 
+** errors are considered fatal.)^  The application must accept 
+** that the backup operation has failed and pass the backup operation handle 
+** to the sqlite3_backup_finish() to release associated resources.
+**
+** ^The first call to sqlite3_backup_step() obtains an exclusive lock
+** on the destination file. ^The exclusive lock is not released until either 
+** sqlite3_backup_finish() is called or the backup operation is complete 
+** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
+** sqlite3_backup_step() obtains a [shared lock] on the source database that
+** lasts for the duration of the sqlite3_backup_step() call.
+** ^Because the source database is not locked between calls to
+** sqlite3_backup_step(), the source database may be modified mid-way
+** through the backup process.  ^If the source database is modified by an
+** external process or via a database connection other than the one being
+** used by the backup operation, then the backup will be automatically
+** restarted by the next call to sqlite3_backup_step(). ^If the source 
+** database is modified by the using the same database connection as is used
+** by the backup operation, then the backup database is automatically
+** updated at the same time.
+**
+** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
+**
+** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 
+** application wishes to abandon the backup operation, the application
+** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
+** ^The sqlite3_backup_finish() interfaces releases all
+** resources associated with the [sqlite3_backup] object. 
+** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
+** active write-transaction on the destination database is rolled back.
+** The [sqlite3_backup] object is invalid
+** and may not be used following a call to sqlite3_backup_finish().
+**
+** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
+** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() completed.
+** ^If an out-of-memory condition or IO error occurred during any prior
+** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
+** sqlite3_backup_finish() returns the corresponding [error code].
+**
+** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
+** is not a permanent error and does not affect the return value of
+** sqlite3_backup_finish().
+**
+** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
+** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
+**
+** ^Each call to sqlite3_backup_step() sets two values inside
+** the [sqlite3_backup] object: the number of pages still to be backed
+** up and the total number of pages in the source database file.
+** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
+** retrieve these two values, respectively.
+**
+** ^The values returned by these functions are only updated by
+** sqlite3_backup_step(). ^If the source database is modified during a backup
+** operation, then the values are not updated to account for any extra
+** pages that need to be updated or the size of the source database file
+** changing.
+**
+** <b>Concurrent Usage of Database Handles</b>
+**
+** ^The source [database connection] may be used by the application for other
+** purposes while a backup operation is underway or being initialized.
+** ^If SQLite is compiled and configured to support threadsafe database
+** connections, then the source database connection may be used concurrently
+** from within other threads.
+**
+** However, the application must guarantee that the destination 
+** [database connection] is not passed to any other API (by any thread) after 
+** sqlite3_backup_init() is called and before the corresponding call to
+** sqlite3_backup_finish().  SQLite does not currently check to see
+** if the application incorrectly accesses the destination [database connection]
+** and so no error code is reported, but the operations may malfunction
+** nevertheless.  Use of the destination database connection while a
+** backup is in progress might also also cause a mutex deadlock.
+**
+** If running in [shared cache mode], the application must
+** guarantee that the shared cache used by the destination database
+** is not accessed while the backup is running. In practice this means
+** that the application must guarantee that the disk file being 
+** backed up to is not accessed by any connection within the process,
+** not just the specific connection that was passed to sqlite3_backup_init().
+**
+** The [sqlite3_backup] object itself is partially threadsafe. Multiple 
+** threads may safely make multiple concurrent calls to sqlite3_backup_step().
+** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
+** APIs are not strictly speaking threadsafe. If they are invoked at the
+** same time as another thread is invoking sqlite3_backup_step() it is
+** possible that they return invalid values.
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3 *pDest,                        /* Destination database handle */
+  const char *zDestName,                 /* Destination database name */
+  sqlite3 *pSource,                      /* Source database handle */
+  const char *zSourceName                /* Source database name */
+);
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
+
+/*
+** CAPI3REF: Unlock Notification
+**
+** ^When running in shared-cache mode, a database operation may fail with
+** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
+** individual tables within the shared-cache cannot be obtained. See
+** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 
+** ^This API may be used to register a callback that SQLite will invoke 
+** when the connection currently holding the required lock relinquishes it.
+** ^This API is only available if the library was compiled with the
+** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
+**
+** See Also: [Using the SQLite Unlock Notification Feature].
+**
+** ^Shared-cache locks are released when a database connection concludes
+** its current transaction, either by committing it or rolling it back. 
+**
+** ^When a connection (known as the blocked connection) fails to obtain a
+** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
+** identity of the database connection (the blocking connection) that
+** has locked the required resource is stored internally. ^After an 
+** application receives an SQLITE_LOCKED error, it may call the
+** sqlite3_unlock_notify() method with the blocked connection handle as 
+** the first argument to register for a callback that will be invoked
+** when the blocking connections current transaction is concluded. ^The
+** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
+** call that concludes the blocking connections transaction.
+**
+** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
+** there is a chance that the blocking connection will have already
+** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
+** If this happens, then the specified callback is invoked immediately,
+** from within the call to sqlite3_unlock_notify().)^
+**
+** ^If the blocked connection is attempting to obtain a write-lock on a
+** shared-cache table, and more than one other connection currently holds
+** a read-lock on the same table, then SQLite arbitrarily selects one of 
+** the other connections to use as the blocking connection.
+**
+** ^(There may be at most one unlock-notify callback registered by a 
+** blocked connection. If sqlite3_unlock_notify() is called when the
+** blocked connection already has a registered unlock-notify callback,
+** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
+** called with a NULL pointer as its second argument, then any existing
+** unlock-notify callback is canceled. ^The blocked connections 
+** unlock-notify callback may also be canceled by closing the blocked
+** connection using [sqlite3_close()].
+**
+** The unlock-notify callback is not reentrant. If an application invokes
+** any sqlite3_xxx API functions from within an unlock-notify callback, a
+** crash or deadlock may be the result.
+**
+** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
+** returns SQLITE_OK.
+**
+** <b>Callback Invocation Details</b>
+**
+** When an unlock-notify callback is registered, the application provides a 
+** single void* pointer that is passed to the callback when it is invoked.
+** However, the signature of the callback function allows SQLite to pass
+** it an array of void* context pointers. The first argument passed to
+** an unlock-notify callback is a pointer to an array of void* pointers,
+** and the second is the number of entries in the array.
+**
+** When a blocking connections transaction is concluded, there may be
+** more than one blocked connection that has registered for an unlock-notify
+** callback. ^If two or more such blocked connections have specified the
+** same callback function, then instead of invoking the callback function
+** multiple times, it is invoked once with the set of void* context pointers
+** specified by the blocked connections bundled together into an array.
+** This gives the application an opportunity to prioritize any actions 
+** related to the set of unblocked database connections.
+**
+** <b>Deadlock Detection</b>
+**
+** Assuming that after registering for an unlock-notify callback a 
+** database waits for the callback to be issued before taking any further
+** action (a reasonable assumption), then using this API may cause the
+** application to deadlock. For example, if connection X is waiting for
+** connection Y's transaction to be concluded, and similarly connection
+** Y is waiting on connection X's transaction, then neither connection
+** will proceed and the system may remain deadlocked indefinitely.
+**
+** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
+** detection. ^If a given call to sqlite3_unlock_notify() would put the
+** system in a deadlocked state, then SQLITE_LOCKED is returned and no
+** unlock-notify callback is registered. The system is said to be in
+** a deadlocked state if connection A has registered for an unlock-notify
+** callback on the conclusion of connection B's transaction, and connection
+** B has itself registered for an unlock-notify callback when connection
+** A's transaction is concluded. ^Indirect deadlock is also detected, so
+** the system is also considered to be deadlocked if connection B has
+** registered for an unlock-notify callback on the conclusion of connection
+** C's transaction, where connection C is waiting on connection A. ^Any
+** number of levels of indirection are allowed.
+**
+** <b>The "DROP TABLE" Exception</b>
+**
+** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 
+** always appropriate to call sqlite3_unlock_notify(). There is however,
+** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
+** SQLite checks if there are any currently executing SELECT statements
+** that belong to the same connection. If there are, SQLITE_LOCKED is
+** returned. In this case there is no "blocking connection", so invoking
+** sqlite3_unlock_notify() results in the unlock-notify callback being
+** invoked immediately. If the application then re-attempts the "DROP TABLE"
+** or "DROP INDEX" query, an infinite loop might be the result.
+**
+** One way around this problem is to check the extended error code returned
+** by an sqlite3_step() call. ^(If there is a blocking connection, then the
+** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
+** the special "DROP TABLE/INDEX" case, the extended error code is just 
+** SQLITE_LOCKED.)^
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *pBlocked,                          /* Waiting connection */
+  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
+  void *pNotifyArg                            /* Argument to pass to xNotify */
+);
+
+
+/*
+** CAPI3REF: String Comparison
+**
+** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
+** and extensions to compare the contents of two buffers containing UTF-8
+** strings in a case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *, const char *);
+SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
+
+/*
+** CAPI3REF: Error Logging Interface
+**
+** ^The [sqlite3_log()] interface writes a message into the error log
+** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
+** ^If logging is enabled, the zFormat string and subsequent arguments are
+** used with [sqlite3_snprintf()] to generate the final output string.
+**
+** The sqlite3_log() interface is intended for use by extensions such as
+** virtual tables, collating functions, and SQL functions.  While there is
+** nothing to prevent an application from calling sqlite3_log(), doing so
+** is considered bad form.
+**
+** The zFormat string must not be NULL.
+**
+** To avoid deadlocks and other threading problems, the sqlite3_log() routine
+** will not use dynamically allocated memory.  The log message is stored in
+** a fixed-length buffer on the stack.  If the log message is longer than
+** a few hundred characters, it will be truncated to the length of the
+** buffer.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
+
+/*
+** CAPI3REF: Write-Ahead Log Commit Hook
+**
+** ^The [sqlite3_wal_hook()] function is used to register a callback that
+** will be invoked each time a database connection commits data to a
+** [write-ahead log] (i.e. whenever a transaction is committed in
+** [journal_mode | journal_mode=WAL mode]). 
+**
+** ^The callback is invoked by SQLite after the commit has taken place and 
+** the associated write-lock on the database released, so the implementation 
+** may read, write or [checkpoint] the database as required.
+**
+** ^The first parameter passed to the callback function when it is invoked
+** is a copy of the third parameter passed to sqlite3_wal_hook() when
+** registering the callback. ^The second is a copy of the database handle.
+** ^The third parameter is the name of the database that was written to -
+** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
+** is the number of pages currently in the write-ahead log file,
+** including those that were just committed.
+**
+** The callback function should normally return [SQLITE_OK].  ^If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to report an error, though the commit will have still occurred. If the
+** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
+** that does not correspond to any valid SQLite error code, the results
+** are undefined.
+**
+** A single database handle may have at most a single write-ahead log callback 
+** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
+** previously registered write-ahead log callback. ^Note that the
+** [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
+** those overwrite any prior [sqlite3_wal_hook()] settings.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3*, 
+  int(*)(void *,sqlite3*,const char*,int),
+  void*
+);
+
+/*
+** CAPI3REF: Configure an auto-checkpoint
+**
+** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
+** [sqlite3_wal_hook()] that causes any database on [database connection] D
+** to automatically [checkpoint]
+** after committing a transaction if there are N or
+** more frames in the [write-ahead log] file.  ^Passing zero or 
+** a negative value as the nFrame parameter disables automatic
+** checkpoints entirely.
+**
+** ^The callback registered by this function replaces any existing callback
+** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
+** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
+** configured by this function.
+**
+** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
+** from SQL.
+**
+** ^Every new [database connection] defaults to having the auto-checkpoint
+** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
+** pages.  The use of this interface
+** is only necessary if the default setting is found to be suboptimal
+** for a particular application.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Checkpoint a database
+**
+** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
+** on [database connection] D to be [checkpointed].  ^If X is NULL or an
+** empty string, then a checkpoint is run on all databases of
+** connection D.  ^If the database connection D is not in
+** [WAL | write-ahead log mode] then this interface is a harmless no-op.
+**
+** ^The [wal_checkpoint pragma] can be used to invoke this interface
+** from SQL.  ^The [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] can be used to cause this interface to be
+** run whenever the WAL reaches a certain size threshold.
+**
+** See also: [sqlite3_wal_checkpoint_v2()]
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Checkpoint a database
+**
+** Run a checkpoint operation on WAL database zDb attached to database 
+** handle db. The specific operation is determined by the value of the 
+** eMode parameter:
+**
+** <dl>
+** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
+**   Checkpoint as many frames as possible without waiting for any database 
+**   readers or writers to finish. Sync the db file if all frames in the log
+**   are checkpointed. This mode is the same as calling 
+**   sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
+**
+** <dt>SQLITE_CHECKPOINT_FULL<dd>
+**   This mode blocks (calls the busy-handler callback) until there is no
+**   database writer and all readers are reading from the most recent database
+**   snapshot. It then checkpoints all frames in the log file and syncs the
+**   database file. This call blocks database writers while it is running,
+**   but not database readers.
+**
+** <dt>SQLITE_CHECKPOINT_RESTART<dd>
+**   This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 
+**   checkpointing the log file it blocks (calls the busy-handler callback)
+**   until all readers are reading from the database file only. This ensures 
+**   that the next client to write to the database file restarts the log file 
+**   from the beginning. This call blocks database writers while it is running,
+**   but not database readers.
+** </dl>
+**
+** If pnLog is not NULL, then *pnLog is set to the total number of frames in
+** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
+** the total number of checkpointed frames (including any that were already
+** checkpointed when this function is called). *pnLog and *pnCkpt may be
+** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
+** If no values are available because of an error, they are both set to -1
+** before returning to communicate this to the caller.
+**
+** All calls obtain an exclusive "checkpoint" lock on the database file. If
+** any other process is running a checkpoint operation at the same time, the 
+** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 
+** busy-handler configured, it will not be invoked in this case.
+**
+** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 
+** "writer" lock on the database file. If the writer lock cannot be obtained
+** immediately, and a busy-handler is configured, it is invoked and the writer
+** lock retried until either the busy-handler returns 0 or the lock is
+** successfully obtained. The busy-handler is also invoked while waiting for
+** database readers as described above. If the busy-handler returns 0 before
+** the writer lock is obtained or while waiting for database readers, the
+** checkpoint operation proceeds from that point in the same way as 
+** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 
+** without blocking any further. SQLITE_BUSY is returned in this case.
+**
+** If parameter zDb is NULL or points to a zero length string, then the
+** specified operation is attempted on all WAL databases. In this case the
+** values written to output parameters *pnLog and *pnCkpt are undefined. If 
+** an SQLITE_BUSY error is encountered when processing one or more of the 
+** attached WAL databases, the operation is still attempted on any remaining 
+** attached databases and SQLITE_BUSY is returned to the caller. If any other 
+** error occurs while processing an attached database, processing is abandoned 
+** and the error code returned to the caller immediately. If no error 
+** (SQLITE_BUSY or otherwise) is encountered while processing the attached 
+** databases, SQLITE_OK is returned.
+**
+** If database zDb is the name of an attached database that is not in WAL
+** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
+** zDb is not NULL (or a zero length string) and is not the name of any
+** attached database, SQLITE_ERROR is returned to the caller.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+);
+
+/*
+** CAPI3REF: Checkpoint operation parameters
+**
+** These constants can be used as the 3rd parameter to
+** [sqlite3_wal_checkpoint_v2()].  See the [sqlite3_wal_checkpoint_v2()]
+** documentation for additional information about the meaning and use of
+** each of these values.
+*/
+#define SQLITE_CHECKPOINT_PASSIVE 0
+#define SQLITE_CHECKPOINT_FULL    1
+#define SQLITE_CHECKPOINT_RESTART 2
+
+/*
+** CAPI3REF: Virtual Table Interface Configuration
+**
+** This function may be called by either the [xConnect] or [xCreate] method
+** of a [virtual table] implementation to configure
+** various facets of the virtual table interface.
+**
+** If this interface is invoked outside the context of an xConnect or
+** xCreate virtual table method then the behavior is undefined.
+**
+** At present, there is only one option that may be configured using
+** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
+** may be added in the future.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Virtual Table Configuration Options
+**
+** These macros define the various options to the
+** [sqlite3_vtab_config()] interface that [virtual table] implementations
+** can use to customize and optimize their behavior.
+**
+** <dl>
+** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
+** where X is an integer.  If X is zero, then the [virtual table] whose
+** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
+** support constraints.  In this configuration (which is the default) if
+** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
+** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
+** specified as part of the users SQL statement, regardless of the actual
+** ON CONFLICT mode specified.
+**
+** If X is non-zero, then the virtual table implementation guarantees
+** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
+** any modifications to internal or persistent data structures have been made.
+** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 
+** is able to roll back a statement or database transaction, and abandon
+** or continue processing the current SQL statement as appropriate. 
+** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
+** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
+** had been ABORT.
+**
+** Virtual table implementations that are required to handle OR REPLACE
+** must do so within the [xUpdate] method. If a call to the 
+** [sqlite3_vtab_on_conflict()] function indicates that the current ON 
+** CONFLICT policy is REPLACE, the virtual table implementation should 
+** silently replace the appropriate rows within the xUpdate callback and
+** return SQLITE_OK. Or, if this is not possible, it may return
+** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 
+** constraint handling.
+** </dl>
+*/
+#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
+
+/*
+** CAPI3REF: Determine The Virtual Table Conflict Policy
+**
+** This function may only be called from within a call to the [xUpdate] method
+** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
+** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
+** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
+** of the SQL statement that triggered the call to the [xUpdate] method of the
+** [virtual table].
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
+
+/*
+** CAPI3REF: Conflict resolution modes
+**
+** These constants are returned by [sqlite3_vtab_on_conflict()] to
+** inform a [virtual table] implementation what the [ON CONFLICT] mode
+** is for the SQL statement being evaluated.
+**
+** Note that the [SQLITE_IGNORE] constant is also used as a potential
+** return value from the [sqlite3_set_authorizer()] callback and that
+** [SQLITE_ABORT] is also a [result code].
+*/
+#define SQLITE_ROLLBACK 1
+/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
+#define SQLITE_FAIL     3
+/* #define SQLITE_ABORT 4  // Also an error code */
+#define SQLITE_REPLACE  5
+
+
+
 /*
 ** Undo the hack that converts floating point types to integer for
 ** builds on processors without floating point support.
@@ -6734,3 +7034,64 @@ struct sqlite3_pcache_methods {
 }  /* End of the 'extern "C"' block */
 #endif
 #endif
+
+/*
+** 2010 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#ifndef _SQLITE3RTREE_H_
+#define _SQLITE3RTREE_H_
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
+
+/*
+** Register a geometry callback named zGeom that can be used as part of an
+** R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,
+  const char *zGeom,
+#ifdef SQLITE_RTREE_INT_ONLY
+  int (*xGeom)(sqlite3_rtree_geometry*, int n, sqlite3_int64 *a, int *pRes),
+#else
+  int (*xGeom)(sqlite3_rtree_geometry*, int n, double *a, int *pRes),
+#endif
+  void *pContext
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the first
+** argument to callbacks registered using rtree_geometry_callback().
+*/
+struct sqlite3_rtree_geometry {
+  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
+  int nParam;                     /* Size of array aParam[] */
+  double *aParam;                 /* Parameters passed to SQL geom function */
+  void *pUser;                    /* Callback implementation user data */
+  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
+};
+
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif  /* ifndef _SQLITE3RTREE_H_ */
+
diff --git a/sqlite/sqlite3ext.h b/sqlite/sqlite3ext.h
index 0b9345f86..5abcde2c8 100755
--- a/sqlite/sqlite3ext.h
+++ b/sqlite/sqlite3ext.h
@@ -14,8 +14,6 @@
 ** an SQLite instance.  Shared libraries that intend to be loaded
 ** as extensions by SQLite should #include this file instead of 
 ** sqlite3.h.
-**
-** @(#) $Id: sqlite3ext.h,v 1.4 2009-01-28 09:09:17 guy Exp $
 */
 #ifndef _SQLITE3EXT_H_
 #define _SQLITE3EXT_H_
@@ -51,8 +49,10 @@ struct sqlite3_api_routines {
   int  (*busy_timeout)(sqlite3*,int ms);
   int  (*changes)(sqlite3*);
   int  (*close)(sqlite3*);
-  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,int eTextRep,const char*));
-  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,int eTextRep,const void*));
+  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                           int eTextRep,const char*));
+  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                             int eTextRep,const void*));
   const void * (*column_blob)(sqlite3_stmt*,int iCol);
   int  (*column_bytes)(sqlite3_stmt*,int iCol);
   int  (*column_bytes16)(sqlite3_stmt*,int iCol);
@@ -77,10 +77,18 @@ struct sqlite3_api_routines {
   void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
   int  (*complete)(const char*sql);
   int  (*complete16)(const void*sql);
-  int  (*create_collation)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*));
-  int  (*create_collation16)(sqlite3*,const void*,int,void*,int(*)(void*,int,const void*,int,const void*));
-  int  (*create_function)(sqlite3*,const char*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
-  int  (*create_function16)(sqlite3*,const void*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
+  int  (*create_collation)(sqlite3*,const char*,int,void*,
+                           int(*)(void*,int,const void*,int,const void*));
+  int  (*create_collation16)(sqlite3*,const void*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*));
+  int  (*create_function)(sqlite3*,const char*,int,int,void*,
+                          void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xFinal)(sqlite3_context*));
+  int  (*create_function16)(sqlite3*,const void*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*));
   int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
   int  (*data_count)(sqlite3_stmt*pStmt);
   sqlite3 * (*db_handle)(sqlite3_stmt*);
@@ -125,16 +133,19 @@ struct sqlite3_api_routines {
   void  (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
   void  (*result_value)(sqlite3_context*,sqlite3_value*);
   void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
-  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,const char*,const char*),void*);
+  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,
+                         const char*,const char*),void*);
   void  (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
   char * (*snprintf)(int,char*,const char*,...);
   int  (*step)(sqlite3_stmt*);
-  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,char const**,char const**,int*,int*,int*);
+  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,
+                                char const**,char const**,int*,int*,int*);
   void  (*thread_cleanup)(void);
   int  (*total_changes)(sqlite3*);
   void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
   int  (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
-  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,sqlite_int64),void*);
+  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,
+                                         sqlite_int64),void*);
   void * (*user_data)(sqlite3_context*);
   const void * (*value_blob)(sqlite3_value*);
   int  (*value_bytes)(sqlite3_value*);
@@ -156,15 +167,19 @@ struct sqlite3_api_routines {
   int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
   int (*clear_bindings)(sqlite3_stmt*);
   /* Added by 3.4.1 */
-  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,void (*xDestroy)(void *));
+  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,
+                          void (*xDestroy)(void *));
   /* Added by 3.5.0 */
   int (*bind_zeroblob)(sqlite3_stmt*,int,int);
   int (*blob_bytes)(sqlite3_blob*);
   int (*blob_close)(sqlite3_blob*);
-  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,int,sqlite3_blob**);
+  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,
+                   int,sqlite3_blob**);
   int (*blob_read)(sqlite3_blob*,void*,int,int);
   int (*blob_write)(sqlite3_blob*,const void*,int,int);
-  int (*create_collation_v2)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*),void(*)(void*));
+  int (*create_collation_v2)(sqlite3*,const char*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*),
+                             void(*)(void*));
   int (*file_control)(sqlite3*,const char*,int,void*);
   sqlite3_int64 (*memory_highwater)(int);
   sqlite3_int64 (*memory_used)(void);
@@ -193,6 +208,34 @@ struct sqlite3_api_routines {
   sqlite3_stmt *(*next_stmt)(sqlite3*,sqlite3_stmt*);
   const char *(*sql)(sqlite3_stmt*);
   int (*status)(int,int*,int*,int);
+  int (*backup_finish)(sqlite3_backup*);
+  sqlite3_backup *(*backup_init)(sqlite3*,const char*,sqlite3*,const char*);
+  int (*backup_pagecount)(sqlite3_backup*);
+  int (*backup_remaining)(sqlite3_backup*);
+  int (*backup_step)(sqlite3_backup*,int);
+  const char *(*compileoption_get)(int);
+  int (*compileoption_used)(const char*);
+  int (*create_function_v2)(sqlite3*,const char*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void(*xDestroy)(void*));
+  int (*db_config)(sqlite3*,int,...);
+  sqlite3_mutex *(*db_mutex)(sqlite3*);
+  int (*db_status)(sqlite3*,int,int*,int*,int);
+  int (*extended_errcode)(sqlite3*);
+  void (*log)(int,const char*,...);
+  sqlite3_int64 (*soft_heap_limit64)(sqlite3_int64);
+  const char *(*sourceid)(void);
+  int (*stmt_status)(sqlite3_stmt*,int,int);
+  int (*strnicmp)(const char*,const char*,int);
+  int (*unlock_notify)(sqlite3*,void(*)(void**,int),void*);
+  int (*wal_autocheckpoint)(sqlite3*,int);
+  int (*wal_checkpoint)(sqlite3*,const char*);
+  void *(*wal_hook)(sqlite3*,int(*)(void*,sqlite3*,const char*,int),void*);
+  int (*blob_reopen)(sqlite3_blob*,sqlite3_int64);
+  int (*vtab_config)(sqlite3*,int op,...);
+  int (*vtab_on_conflict)(sqlite3*);
 };
 
 /*
@@ -372,6 +415,30 @@ struct sqlite3_api_routines {
 #define sqlite3_next_stmt              sqlite3_api->next_stmt
 #define sqlite3_sql                    sqlite3_api->sql
 #define sqlite3_status                 sqlite3_api->status
+#define sqlite3_backup_finish          sqlite3_api->backup_finish
+#define sqlite3_backup_init            sqlite3_api->backup_init
+#define sqlite3_backup_pagecount       sqlite3_api->backup_pagecount
+#define sqlite3_backup_remaining       sqlite3_api->backup_remaining
+#define sqlite3_backup_step            sqlite3_api->backup_step
+#define sqlite3_compileoption_get      sqlite3_api->compileoption_get
+#define sqlite3_compileoption_used     sqlite3_api->compileoption_used
+#define sqlite3_create_function_v2     sqlite3_api->create_function_v2
+#define sqlite3_db_config              sqlite3_api->db_config
+#define sqlite3_db_mutex               sqlite3_api->db_mutex
+#define sqlite3_db_status              sqlite3_api->db_status
+#define sqlite3_extended_errcode       sqlite3_api->extended_errcode
+#define sqlite3_log                    sqlite3_api->log
+#define sqlite3_soft_heap_limit64      sqlite3_api->soft_heap_limit64
+#define sqlite3_sourceid               sqlite3_api->sourceid
+#define sqlite3_stmt_status            sqlite3_api->stmt_status
+#define sqlite3_strnicmp               sqlite3_api->strnicmp
+#define sqlite3_unlock_notify          sqlite3_api->unlock_notify
+#define sqlite3_wal_autocheckpoint     sqlite3_api->wal_autocheckpoint
+#define sqlite3_wal_checkpoint         sqlite3_api->wal_checkpoint
+#define sqlite3_wal_hook               sqlite3_api->wal_hook
+#define sqlite3_blob_reopen            sqlite3_api->blob_reopen
+#define sqlite3_vtab_config            sqlite3_api->vtab_config
+#define sqlite3_vtab_on_conflict       sqlite3_api->vtab_on_conflict
 #endif /* SQLITE_CORE */
 
 #define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api = 0;