Alessandro Bonazzi 5c7aa8c1c0 Patch level : 12.0 no-patch
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Aggiunta documentazione di sqlite 3
2020-11-29 00:32:36 +01:00

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<h2>SQLite Release 3.12.0 On 2016-03-29</h2><p><ol class='lessindent'>
<p><b>Potentially Disruptive Change:</b>
<li>The <a href="../compile.html#default_page_size">SQLITE_DEFAULT_PAGE_SIZE</a> is increased from 1024 to 4096.
The <a href="../compile.html#default_cache_size">SQLITE_DEFAULT_CACHE_SIZE</a> is changed from 2000 to -2000 so
the same amount of cache memory is used by default.
See the application note on the
<a href="../pgszchng2016.html">version 3.12.0 page size change</a> for further information.
<p><b>Performance enhancements:</b>
<li>Enhancements to the <a href="../lemon.html">Lemon parser generator</a>
so that it creates a smaller and faster SQL parser.
<li>Only create <font color="red">master journal</font> files if two or more attached databases are all
modified, do not have <a href="../pragma.html#pragma_synchronous">PRAGMA synchronous</a> set to OFF, and
do not have the <a href="../pragma.html#pragma_journal_mode">journal_mode</a> set to OFF, MEMORY, or WAL.
<li>Only create <a href="../tempfiles.html#stmtjrnl">statement journal</a> files when their size exceeds a threshold.
Otherwise the journal is held in memory and no I/O occurs. The threshold
can be configured at compile-time using <a href="../compile.html#stmtjrnl_spill">SQLITE_STMTJRNL_SPILL</a> or at
start-time using <a href="../c3ref/config.html">sqlite3_config</a>(<a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigstmtjrnlspill">SQLITE_CONFIG_STMTJRNL_SPILL</a>).
<li>The query planner is able to optimize IN operators on <a href="../vtab.html">virtual tables</a>
even if the <a href="../vtab.html#xbestindex">xBestIndex</a> method does not set the
sqlite3_index_constraint_usage.omit flag of the
virtual table column to the left of the IN operator.
<li>The query planner now does a better job of optimizing <a href="../vtab.html">virtual table</a>
accesses in a 3-way or higher join where constraints on the virtual
table are split across two or more other tables of the join.
<li>More efficient handling of <a href="../appfunc.html">application-defined SQL functions</a>, especially
in cases where the application defines hundreds or thousands of
custom functions.
<li>The query planner considers the LIMIT clause when estimating the cost
of ORDER BY.
<li>The configure script (on unix) automatically detects
pread() and pwrite() and sets compile-time options to use those OS
interfaces if they are available.
<li>Reduce the amount of memory needed to hold the schema.
<li>Other miscellaneous micro-optimizations for improved performance and reduced
memory usage.
<p><b>New Features:</b>
<li>Added the <a href="../c3ref/c_dbconfig_defensive.html#sqlitedbconfigenablefts3tokenizer">SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</a> option to <a href="../c3ref/db_config.html">sqlite3_db_config()</a>
which allows the two-argument version of the <a href="../fts3.html#f3tknzr">fts3_tokenizer()</a> SQL function to
be enabled or disabled at run-time.
<li>Added the <a href="https://www.sqlite.org/src/artifact/d7cc99350?ln=403-443">sqlite3rbu_bp_progress()</a>
interface to the <a href="../rbu.html">RBU</a> extension.
<li>The <a href="../pragma.html#pragma_defer_foreign_keys">PRAGMA defer_foreign_keys=ON</a> statement now also disables
<a href="../foreignkeys.html#fk_actions">RESTRICT actions</a> on foreign key.
<li>Added the <a href="../c3ref/system_errno.html">sqlite3_system_errno()</a> interface.
<li>Added the <a href="../compile.html#default_synchronous">SQLITE_DEFAULT_SYNCHRONOUS</a> and <a href="../compile.html#default_wal_synchronous">SQLITE_DEFAULT_WAL_SYNCHRONOUS</a>
compile-time options. The <a href="../compile.html#default_synchronous">SQLITE_DEFAULT_SYNCHRONOUS</a> compile-time option
replaces the <a href="../compile.html#extra_durable">SQLITE_EXTRA_DURABLE</a> option, which is no longer supported.
<li>Enhanced the ".stats" command in the <a href="../cli.html">command-line shell</a> to show more
information about I/O performance obtained from /proc, when available.
<p><b>Bug fixes:</b>
<li>Make sure the <a href="../c3ref/get_auxdata.html">sqlite3_set_auxdata()</a> values from multiple triggers
within a single statement do not interfere with one another.
Ticket <a href="https://www.sqlite.org/src/info/dc9b1c91">dc9b1c91</a>.
<li>Fix the code generator for expressions of the form "x IN (SELECT...)" where
the SELECT statement on the RHS is a correlated subquery.
Ticket <a href="https://www.sqlite.org/src/info/5e3c886796e5512e">5e3c886796e5512e</a>.
<li>Fix a harmless TSAN warning associated with the <a href="../c3ref/db_readonly.html">sqlite3_db_readonly()</a> interface.
<p><b>Hashes:</b>
<li>SQLITE_SOURCE_ID: "2016-03-29 10:14:15 e9bb4cf40f4971974a74468ef922bdee481c988b"
<li>SHA1 for sqlite3.c: cba2be96d27cb51978cd4a200397a4ad178986eb
</ol></p>
<p>A <a href="../changes.html">complete list of SQLite releases</a>
in a single page and a <a href="../chronology.html">chronology</a> are both also available.
A detailed history of every
check-in is available at
<a href="http://www.sqlite.org/src/timeline">
SQLite version control site</a>.</p>