511 lines
28 KiB
HTML
511 lines
28 KiB
HTML
<!DOCTYPE html>
|
|
<html><head>
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
|
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
|
|
<link href="../sqlite.css" rel="stylesheet">
|
|
<title>Configuration Options</title>
|
|
<!-- path=../ -->
|
|
</head>
|
|
<body>
|
|
<div class=nosearch>
|
|
<a href="../index.html">
|
|
<img class="logo" src="../images/sqlite370_banner.gif" alt="SQLite" border="0">
|
|
</a>
|
|
<div><!-- IE hack to prevent disappearing logo --></div>
|
|
<div class="tagline desktoponly">
|
|
Small. Fast. Reliable.<br>Choose any three.
|
|
</div>
|
|
<div class="menu mainmenu">
|
|
<ul>
|
|
<li><a href="../index.html">Home</a>
|
|
<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a>
|
|
<li class='wideonly'><a href='../about.html'>About</a>
|
|
<li class='desktoponly'><a href="../docs.html">Documentation</a>
|
|
<li class='desktoponly'><a href="../download.html">Download</a>
|
|
<li class='wideonly'><a href='../copyright.html'>License</a>
|
|
<li class='desktoponly'><a href="../support.html">Support</a>
|
|
<li class='desktoponly'><a href="../prosupport.html">Purchase</a>
|
|
<li class='search' id='search_menubutton'>
|
|
<a href="javascript:void(0)" onclick='toggle_search()'>Search</a>
|
|
</ul>
|
|
</div>
|
|
<div class="menu submenu" id="submenu">
|
|
<ul>
|
|
<li><a href='../about.html'>About</a>
|
|
<li><a href='../docs.html'>Documentation</a>
|
|
<li><a href='../download.html'>Download</a>
|
|
<li><a href='../support.html'>Support</a>
|
|
<li><a href='../prosupport.html'>Purchase</a>
|
|
</ul>
|
|
</div>
|
|
<div class="searchmenu" id="searchmenu">
|
|
<form method="GET" action="../search">
|
|
<select name="s" id="searchtype">
|
|
<option value="d">Search Documentation</option>
|
|
<option value="c">Search Changelog</option>
|
|
</select>
|
|
<input type="text" name="q" id="searchbox" value="">
|
|
<input type="submit" value="Go">
|
|
</form>
|
|
</div>
|
|
</div>
|
|
<script>
|
|
function toggle_div(nm) {
|
|
var w = document.getElementById(nm);
|
|
if( w.style.display=="block" ){
|
|
w.style.display = "none";
|
|
}else{
|
|
w.style.display = "block";
|
|
}
|
|
}
|
|
function toggle_search() {
|
|
var w = document.getElementById("searchmenu");
|
|
if( w.style.display=="block" ){
|
|
w.style.display = "none";
|
|
} else {
|
|
w.style.display = "block";
|
|
setTimeout(function(){
|
|
document.getElementById("searchbox").focus()
|
|
}, 30);
|
|
}
|
|
}
|
|
function div_off(nm){document.getElementById(nm).style.display="none";}
|
|
window.onbeforeunload = function(e){div_off("submenu");}
|
|
/* Disable the Search feature if we are not operating from CGI, since */
|
|
/* Search is accomplished using CGI and will not work without it. */
|
|
if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){
|
|
document.getElementById("search_menubutton").style.display = "none";
|
|
}
|
|
/* Used by the Hide/Show button beside syntax diagrams, to toggle the */
|
|
function hideorshow(btn,obj){
|
|
var x = document.getElementById(obj);
|
|
var b = document.getElementById(btn);
|
|
if( x.style.display!='none' ){
|
|
x.style.display = 'none';
|
|
b.innerHTML='show';
|
|
}else{
|
|
x.style.display = '';
|
|
b.innerHTML='hide';
|
|
}
|
|
return false;
|
|
}
|
|
</script>
|
|
</div>
|
|
<!-- keywords: SQLITE_CONFIG_COVERING_INDEX_SCAN SQLITE_CONFIG_GETMALLOC SQLITE_CONFIG_GETMUTEX SQLITE_CONFIG_GETPCACHE SQLITE_CONFIG_GETPCACHE2 SQLITE_CONFIG_HEAP SQLITE_CONFIG_LOG SQLITE_CONFIG_LOOKASIDE SQLITE_CONFIG_MALLOC SQLITE_CONFIG_MEMDB_MAXSIZE SQLITE_CONFIG_MEMSTATUS SQLITE_CONFIG_MMAP_SIZE SQLITE_CONFIG_MULTITHREAD SQLITE_CONFIG_MUTEX SQLITE_CONFIG_PAGECACHE SQLITE_CONFIG_PCACHE SQLITE_CONFIG_PCACHE2 SQLITE_CONFIG_PCACHE_HDRSZ SQLITE_CONFIG_PMASZ SQLITE_CONFIG_SCRATCH SQLITE_CONFIG_SERIALIZED SQLITE_CONFIG_SINGLETHREAD SQLITE_CONFIG_SMALL_MALLOC SQLITE_CONFIG_SORTERREF_SIZE SQLITE_CONFIG_SQLLOG SQLITE_CONFIG_STMTJRNL_SPILL SQLITE_CONFIG_URI SQLITE_CONFIG_WIN32_HEAPSIZE {configuration option} -->
|
|
<div class=nosearch>
|
|
<a href="intro.html"><h2>SQLite C Interface</h2></a>
|
|
<h2>Configuration Options</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
|
|
#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
|
|
#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
|
|
#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
|
|
#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
|
|
#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
|
|
#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
|
|
#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
|
|
#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
|
|
#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_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 /* 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* */
|
|
#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
|
|
#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
|
|
#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
|
|
#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
|
|
#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
|
|
#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
|
|
#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
|
|
#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
|
|
#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
|
|
#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants are the available integer configuration options that
|
|
can be passed as the first argument to the <a href="../c3ref/config.html">sqlite3_config()</a> interface.</p>
|
|
|
|
<p>New configuration options may be added in future releases of SQLite.
|
|
Existing configuration options might be discontinued. Applications
|
|
should check the return code from <a href="../c3ref/config.html">sqlite3_config()</a> to make sure that
|
|
the call worked. The <a href="../c3ref/config.html">sqlite3_config()</a> interface will return a
|
|
non-zero <a href="../rescode.html">error code</a> if a discontinued or unsupported configuration option
|
|
is invoked.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqliteconfigsinglethread"></a>
|
|
<dt>SQLITE_CONFIG_SINGLETHREAD</dt>
|
|
<dd>There are no arguments to this option. This option sets the
|
|
<a href="../threadsafe.html">threading mode</a> 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. If SQLite is compiled with
|
|
the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
it is not possible to change the <a href="../threadsafe.html">threading mode</a> from its default
|
|
value of Single-thread and so <a href="../c3ref/config.html">sqlite3_config()</a> will return
|
|
<a href="../rescode.html#error">SQLITE_ERROR</a> if called with the SQLITE_CONFIG_SINGLETHREAD
|
|
configuration option.</dd></p>
|
|
|
|
<p><a name="sqliteconfigmultithread"></a>
|
|
<dt>SQLITE_CONFIG_MULTITHREAD</dt>
|
|
<dd>There are no arguments to this option. This option sets the
|
|
<a href="../threadsafe.html">threading mode</a> to Multi-thread. In other words, it disables
|
|
mutexing on <a href="../c3ref/sqlite3.html">database connection</a> and <a href="../c3ref/stmt.html">prepared statement</a> objects.
|
|
The application is responsible for serializing access to
|
|
<a href="../c3ref/sqlite3.html">database connections</a> and <a href="../c3ref/stmt.html">prepared statements</a>. 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
|
|
<a href="../c3ref/sqlite3.html">database connection</a> at the same time. If SQLite is compiled with
|
|
the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
it is not possible to set the Multi-thread <a href="../threadsafe.html">threading mode</a> and
|
|
<a href="../c3ref/config.html">sqlite3_config()</a> will return <a href="../rescode.html#error">SQLITE_ERROR</a> if called with the
|
|
SQLITE_CONFIG_MULTITHREAD configuration option.</dd></p>
|
|
|
|
<p><a name="sqliteconfigserialized"></a>
|
|
<dt>SQLITE_CONFIG_SERIALIZED</dt>
|
|
<dd>There are no arguments to this option. This option sets the
|
|
<a href="../threadsafe.html">threading mode</a> to Serialized. In other words, this option enables
|
|
all mutexes including the recursive
|
|
mutexes on <a href="../c3ref/sqlite3.html">database connection</a> and <a href="../c3ref/stmt.html">prepared statement</a> objects.
|
|
In this mode (which is the default when SQLite is compiled with
|
|
<a href="../compile.html#threadsafe">SQLITE_THREADSAFE=1</a>) the SQLite library will itself serialize access
|
|
to <a href="../c3ref/sqlite3.html">database connections</a> and <a href="../c3ref/stmt.html">prepared statements</a> so that the
|
|
application is free to use the same <a href="../c3ref/sqlite3.html">database connection</a> or the
|
|
same <a href="../c3ref/stmt.html">prepared statement</a> in different threads at the same time.
|
|
If SQLite is compiled with
|
|
the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
it is not possible to set the Serialized <a href="../threadsafe.html">threading mode</a> and
|
|
<a href="../c3ref/config.html">sqlite3_config()</a> will return <a href="../rescode.html#error">SQLITE_ERROR</a> if called with the
|
|
SQLITE_CONFIG_SERIALIZED configuration option.</dd></p>
|
|
|
|
<p><a name="sqliteconfigmalloc"></a>
|
|
<dt>SQLITE_CONFIG_MALLOC</dt>
|
|
<dd> The SQLITE_CONFIG_MALLOC option takes a single argument which is
|
|
a pointer to an instance of the <a href="../c3ref/mem_methods.html">sqlite3_mem_methods</a> structure.
|
|
The argument specifies
|
|
alternative low-level memory allocation routines to be used in place of
|
|
the memory allocation routines built into SQLite. SQLite makes
|
|
its own private copy of the content of the <a href="../c3ref/mem_methods.html">sqlite3_mem_methods</a> structure
|
|
before the <a href="../c3ref/config.html">sqlite3_config()</a> call returns.</dd></p>
|
|
|
|
<p><a name="sqliteconfiggetmalloc"></a>
|
|
<dt>SQLITE_CONFIG_GETMALLOC</dt>
|
|
<dd> The SQLITE_CONFIG_GETMALLOC option takes a single argument which
|
|
is a pointer to an instance of the <a href="../c3ref/mem_methods.html">sqlite3_mem_methods</a> structure.
|
|
The <a href="../c3ref/mem_methods.html">sqlite3_mem_methods</a>
|
|
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></p>
|
|
|
|
<p><a name="sqliteconfigsmallmalloc"></a>
|
|
<dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
|
|
<dd> The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
|
|
type int, interpreted as a boolean, which if true provides a hint to
|
|
SQLite that it should avoid large memory allocations if possible.
|
|
SQLite will run faster if it is free to make large memory allocations,
|
|
but some application might prefer to run slower in exchange for
|
|
guarantees about memory fragmentation that are possible if large
|
|
allocations are avoided. This hint is normally off.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigmemstatus"></a>
|
|
<dt>SQLITE_CONFIG_MEMSTATUS</dt>
|
|
<dd> The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
|
|
interpreted as a boolean, which enables or disables the collection of
|
|
memory allocation statistics. When memory allocation statistics are
|
|
disabled, the following SQLite interfaces become non-operational:
|
|
<ul>
|
|
<li> <a href="../c3ref/hard_heap_limit64.html">sqlite3_hard_heap_limit64()</a>
|
|
<li> <a href="../c3ref/memory_highwater.html">sqlite3_memory_used()</a>
|
|
<li> <a href="../c3ref/memory_highwater.html">sqlite3_memory_highwater()</a>
|
|
<li> <a href="../c3ref/hard_heap_limit64.html">sqlite3_soft_heap_limit64()</a>
|
|
<li> <a href="../c3ref/status.html">sqlite3_status64()</a>
|
|
</ul>
|
|
Memory allocation statistics are enabled by default unless SQLite is
|
|
compiled with <a href="../compile.html#default_memstatus">SQLITE_DEFAULT_MEMSTATUS</a>=0 in which case memory
|
|
allocation statistics are disabled by default.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigscratch"></a>
|
|
<dt>SQLITE_CONFIG_SCRATCH</dt>
|
|
<dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigpagecache"></a>
|
|
<dt>SQLITE_CONFIG_PAGECACHE</dt>
|
|
<dd> The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
|
|
that SQLite can use for the database page cache with the default page
|
|
cache implementation.
|
|
This configuration option is a no-op if an application-defined page
|
|
cache implementation is loaded using the <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigpcache2">SQLITE_CONFIG_PCACHE2</a>.
|
|
There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
|
|
8-byte aligned memory (pMem), the size of each page cache line (sz),
|
|
and the number of cache lines (N).
|
|
The sz argument should be the size of the largest database page
|
|
(a power of two between 512 and 65536) plus some extra bytes for each
|
|
page header. The number of extra bytes needed by the page header
|
|
can be determined using <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigpcachehdrsz">SQLITE_CONFIG_PCACHE_HDRSZ</a>.
|
|
It is harmless, apart from the wasted memory,
|
|
for the sz parameter to be larger than necessary. The pMem
|
|
argument must be either a NULL pointer or a pointer to an 8-byte
|
|
aligned block of memory of at least sz*N bytes, otherwise
|
|
subsequent behavior is undefined.
|
|
When pMem is not NULL, SQLite will strive to use the memory provided
|
|
to satisfy page cache needs, falling back to <a href="../c3ref/free.html">sqlite3_malloc()</a> if
|
|
a page cache line is larger than sz bytes or if all of the pMem buffer
|
|
is exhausted.
|
|
If pMem is NULL and N is non-zero, then each database connection
|
|
does an initial bulk allocation for page cache memory
|
|
from <a href="../c3ref/free.html">sqlite3_malloc()</a> sufficient for N cache lines if N is positive or
|
|
of -1024*N bytes if N is negative, . If additional
|
|
page cache memory is needed beyond what is provided by the initial
|
|
allocation, then SQLite goes to <a href="../c3ref/free.html">sqlite3_malloc()</a> separately for each
|
|
additional cache line. </dd></p>
|
|
|
|
<p><a name="sqliteconfigheap"></a>
|
|
<dt>SQLITE_CONFIG_HEAP</dt>
|
|
<dd> The SQLITE_CONFIG_HEAP option specifies a static memory buffer
|
|
that SQLite will use for all of its dynamic memory allocation needs
|
|
beyond those provided for by <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>.
|
|
The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
|
|
with either <a href="../compile.html#enable_memsys3">SQLITE_ENABLE_MEMSYS3</a> or <a href="../compile.html#enable_memsys5">SQLITE_ENABLE_MEMSYS5</a> and returns
|
|
<a href="../rescode.html#error">SQLITE_ERROR</a> if invoked otherwise.
|
|
There are three arguments to SQLITE_CONFIG_HEAP:
|
|
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 <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a>. If the
|
|
memory pointer is not NULL then the alternative memory
|
|
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></p>
|
|
|
|
<p><a name="sqliteconfigmutex"></a>
|
|
<dt>SQLITE_CONFIG_MUTEX</dt>
|
|
<dd> The SQLITE_CONFIG_MUTEX option takes a single argument which is a
|
|
pointer to an instance of the <a href="../c3ref/mutex_methods.html">sqlite3_mutex_methods</a> structure.
|
|
The argument specifies alternative low-level mutex routines to be used
|
|
in place the mutex routines built into SQLite. SQLite makes a copy of
|
|
the content of the <a href="../c3ref/mutex_methods.html">sqlite3_mutex_methods</a> structure before the call to
|
|
<a href="../c3ref/config.html">sqlite3_config()</a> returns. If SQLite is compiled with
|
|
the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
the entire mutexing subsystem is omitted from the build and hence calls to
|
|
<a href="../c3ref/config.html">sqlite3_config()</a> with the SQLITE_CONFIG_MUTEX configuration option will
|
|
return <a href="../rescode.html#error">SQLITE_ERROR</a>.</dd></p>
|
|
|
|
<p><a name="sqliteconfiggetmutex"></a>
|
|
<dt>SQLITE_CONFIG_GETMUTEX</dt>
|
|
<dd> The SQLITE_CONFIG_GETMUTEX option takes a single argument which
|
|
is a pointer to an instance of the <a href="../c3ref/mutex_methods.html">sqlite3_mutex_methods</a> structure. The
|
|
<a href="../c3ref/mutex_methods.html">sqlite3_mutex_methods</a>
|
|
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. If SQLite is compiled with
|
|
the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
the entire mutexing subsystem is omitted from the build and hence calls to
|
|
<a href="../c3ref/config.html">sqlite3_config()</a> with the SQLITE_CONFIG_GETMUTEX configuration option will
|
|
return <a href="../rescode.html#error">SQLITE_ERROR</a>.</dd></p>
|
|
|
|
<p><a name="sqliteconfiglookaside"></a>
|
|
<dt>SQLITE_CONFIG_LOOKASIDE</dt>
|
|
<dd> The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
|
|
the default size of lookaside memory on each <a href="../c3ref/sqlite3.html">database connection</a>.
|
|
The first argument is the
|
|
size of each lookaside buffer slot and the second is the number of
|
|
slots allocated to each database connection. SQLITE_CONFIG_LOOKASIDE
|
|
sets the <i>default</i> lookaside size. The <a href="../c3ref/c_dbconfig_defensive.html#sqlitedbconfiglookaside">SQLITE_DBCONFIG_LOOKASIDE</a>
|
|
option to <a href="../c3ref/db_config.html">sqlite3_db_config()</a> can be used to change the lookaside
|
|
configuration on individual connections. </dd></p>
|
|
|
|
<p><a name="sqliteconfigpcache2"></a>
|
|
<dt>SQLITE_CONFIG_PCACHE2</dt>
|
|
<dd> The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
|
|
a pointer to an <a href="../c3ref/pcache_methods2.html">sqlite3_pcache_methods2</a> object. This object specifies
|
|
the interface to a custom page cache implementation.
|
|
SQLite makes a copy of the <a href="../c3ref/pcache_methods2.html">sqlite3_pcache_methods2</a> object.</dd></p>
|
|
|
|
<p><a name="sqliteconfiggetpcache2"></a>
|
|
<dt>SQLITE_CONFIG_GETPCACHE2</dt>
|
|
<dd> The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
|
|
is a pointer to an <a href="../c3ref/pcache_methods2.html">sqlite3_pcache_methods2</a> object. SQLite copies of
|
|
the current page cache implementation into that object. </dd></p>
|
|
|
|
<p><a name="sqliteconfiglog"></a>
|
|
<dt>SQLITE_CONFIG_LOG</dt>
|
|
<dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
|
|
global <a href="../errlog.html">error log</a>.
|
|
(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 <a href="../c3ref/log.html">sqlite3_log()</a> to process each logging event. If the
|
|
function pointer is NULL, the <a href="../c3ref/log.html">sqlite3_log()</a> 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
|
|
<a href="../c3ref/log.html">sqlite3_log()</a> call and is intended to be a <a href="../rescode.html">result code</a> or an
|
|
<a href="../rescode.html#extrc">extended result code</a>. The third parameter passed to the logger is
|
|
log message after formatting via <a href="../c3ref/mprintf.html">sqlite3_snprintf()</a>.
|
|
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></p>
|
|
|
|
<p><a name="sqliteconfiguri"></a>
|
|
<dt>SQLITE_CONFIG_URI
|
|
<dd>The SQLITE_CONFIG_URI 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 <a href="../c3ref/open.html">sqlite3_open()</a>, <a href="../c3ref/open.html">sqlite3_open_v2()</a>,
|
|
<a href="../c3ref/open.html">sqlite3_open16()</a> or
|
|
specified as part of <a href="../lang_attach.html">ATTACH</a> commands are interpreted as URIs, regardless
|
|
of whether or not the <a href="../c3ref/c_open_autoproxy.html">SQLITE_OPEN_URI</a> 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
|
|
<a href="../compile.html#use_uri">SQLITE_USE_URI</a> symbol defined.</p>
|
|
|
|
<p><a name="sqliteconfigcoveringindexscan"></a>
|
|
<dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
|
|
<dd>The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
|
|
argument which is interpreted as a boolean in order to enable or disable
|
|
the use of covering indices for full table scans in the query optimizer.
|
|
The default setting is determined
|
|
by the <a href="../compile.html#allow_covering_index_scan">SQLITE_ALLOW_COVERING_INDEX_SCAN</a> compile-time option, or is "on"
|
|
if that compile-time option is omitted.
|
|
The ability to disable the use of covering indices for full table scans
|
|
is because some incorrectly coded legacy applications might malfunction
|
|
when the optimization is enabled. Providing the ability to
|
|
disable the optimization allows the older, buggy application code to work
|
|
without change even with newer versions of SQLite.</p>
|
|
|
|
<p><a name="sqliteconfigpcache"></a>
|
|
<a name="sqliteconfiggetpcache"></a>
|
|
|
|
<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.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigsqllog"></a>
|
|
|
|
<dt>SQLITE_CONFIG_SQLLOG
|
|
<dd>This option is only available if sqlite is compiled with the
|
|
<a href="../compile.html#enable_sqllog">SQLITE_ENABLE_SQLLOG</a> pre-processor macro defined. The first argument should
|
|
be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
|
|
The second should be of type (void*). The callback is invoked by the library
|
|
in three separate circumstances, identified by the value passed as the
|
|
fourth parameter. If the fourth parameter is 0, then the database connection
|
|
passed as the second argument has just been opened. The third argument
|
|
points to a buffer containing the name of the main database file. If the
|
|
fourth parameter is 1, then the SQL statement that the third parameter
|
|
points to has just been executed. Or, if the fourth parameter is 2, then
|
|
the connection being passed as the second parameter is being closed. The
|
|
third parameter is passed NULL In this case. An example of using this
|
|
configuration option can be seen in the "test_sqllog.c" source file in
|
|
the canonical SQLite source tree.</dd></p>
|
|
|
|
<p><a name="sqliteconfigmmapsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_MMAP_SIZE
|
|
<dd>SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
|
|
that are the default mmap size limit (the default setting for
|
|
<a href="../pragma.html#pragma_mmap_size">PRAGMA mmap_size</a>) and the maximum allowed mmap size limit.
|
|
The default setting can be overridden by each database connection using
|
|
either the <a href="../pragma.html#pragma_mmap_size">PRAGMA mmap_size</a> command, or by using the
|
|
<a href="../c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlmmapsize">SQLITE_FCNTL_MMAP_SIZE</a> file control. The maximum allowed mmap size
|
|
will be silently truncated if necessary so that it does not exceed the
|
|
compile-time maximum mmap size set by the
|
|
<a href="../compile.html#max_mmap_size">SQLITE_MAX_MMAP_SIZE</a> compile-time option.
|
|
If either argument to this option is negative, then that argument is
|
|
changed to its compile-time default.</p>
|
|
|
|
<p><a name="sqliteconfigwin32heapsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_WIN32_HEAPSIZE
|
|
<dd>The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
|
|
compiled for Windows with the <a href="../compile.html#win32_malloc">SQLITE_WIN32_MALLOC</a> pre-processor macro
|
|
defined. SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
|
|
that specifies the maximum size of the created heap.</p>
|
|
|
|
<p><a name="sqliteconfigpcachehdrsz"></a>
|
|
|
|
<dt>SQLITE_CONFIG_PCACHE_HDRSZ
|
|
<dd>The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
|
|
is a pointer to an integer and writes into that integer the number of extra
|
|
bytes per page required for each page in <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>.
|
|
The amount of extra space required can change depending on the compiler,
|
|
target platform, and SQLite version.</p>
|
|
|
|
<p><a name="sqliteconfigpmasz"></a>
|
|
|
|
<dt>SQLITE_CONFIG_PMASZ
|
|
<dd>The SQLITE_CONFIG_PMASZ option takes a single parameter which
|
|
is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
|
|
sorter to that integer. The default minimum PMA Size is set by the
|
|
<a href="../compile.html#sorter_pmasz">SQLITE_SORTER_PMASZ</a> compile-time option. New threads are launched
|
|
to help with sort operations when multithreaded sorting
|
|
is enabled (using the <a href="../pragma.html#pragma_threads">PRAGMA threads</a> command) and the amount of content
|
|
to be sorted exceeds the page size times the minimum of the
|
|
<a href="../pragma.html#pragma_cache_size">PRAGMA cache_size</a> setting and this value.</p>
|
|
|
|
<p><a name="sqliteconfigstmtjrnlspill"></a>
|
|
|
|
<dt>SQLITE_CONFIG_STMTJRNL_SPILL
|
|
<dd>The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
|
|
becomes the <a href="../tempfiles.html#stmtjrnl">statement journal</a> spill-to-disk threshold.
|
|
<a href="../tempfiles.html#stmtjrnl">Statement journals</a> are held in memory until their size (in bytes)
|
|
exceeds this threshold, at which point they are written to disk.
|
|
Or if the threshold is -1, statement journals are always held
|
|
exclusively in memory.
|
|
Since many statement journals never become large, setting the spill
|
|
threshold to a value such as 64KiB can greatly reduce the amount of
|
|
I/O required to support statement rollback.
|
|
The default value for this setting is controlled by the
|
|
<a href="../compile.html#stmtjrnl_spill">SQLITE_STMTJRNL_SPILL</a> compile-time option.</p>
|
|
|
|
<p><a name="sqliteconfigsorterrefsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_SORTERREF_SIZE
|
|
<dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
|
|
of type (int) - the new value of the sorter-reference size threshold.
|
|
Usually, when SQLite uses an external sort to order records according
|
|
to an ORDER BY clause, all fields required by the caller are present in the
|
|
sorted records. However, if SQLite determines based on the declared type
|
|
of a table column that its values are likely to be very large - larger
|
|
than the configured sorter-reference size threshold - then a reference
|
|
is stored in each sorted record and the required column values loaded
|
|
from the database as records are returned in sorted order. The default
|
|
value for this option is to never use this optimization. Specifying a
|
|
negative value for this option restores the default behaviour.
|
|
This option is only available if SQLite is compiled with the
|
|
<a href="../compile.html#enable_sorter_references">SQLITE_ENABLE_SORTER_REFERENCES</a> compile-time option.</p>
|
|
|
|
<p><a name="sqliteconfigmemdbmaxsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_MEMDB_MAXSIZE
|
|
<dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
|
|
<a href="../c3ref/int64.html">sqlite3_int64</a> parameter which is the default maximum size for an in-memory
|
|
database created using <a href="../c3ref/deserialize.html">sqlite3_deserialize()</a>. This default maximum
|
|
size can be adjusted up or down for individual databases using the
|
|
<a href="../c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlsizelimit">SQLITE_FCNTL_SIZE_LIMIT</a> <a href="../c3ref/file_control.html">file-control</a>. If this
|
|
configuration setting is never used, then the default maximum is determined
|
|
by the <a href="../compile.html#memdb_default_maxsize">SQLITE_MEMDB_DEFAULT_MAXSIZE</a> compile-time option. If that
|
|
compile-time option is not set, then the default maximum is 1073741824.
|
|
</dl>
|
|
</p><p>See also lists of
|
|
<a href="objlist.html">Objects</a>,
|
|
<a href="constlist.html">Constants</a>, and
|
|
<a href="funclist.html">Functions</a>.</p>
|