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Comment:Import the SQLite core library docs from upstream that correspond to version 3.12.0.
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SHA1: 94e181cde011a74ad8597d67ad93791c8485363b
User & Date: mistachkin 2016-03-29 20:40:56
Context
2016-03-30
21:02
Update the MSVCRT runtimes for VS 2015 in externals to 'Update 2', part 1. check-in: f586f38b68 user: mistachkin tags: trunk
2016-03-29
20:40
Import the SQLite core library docs from upstream that correspond to version 3.12.0. check-in: 94e181cde0 user: mistachkin tags: trunk
18:10
Update SQLite core library to the 3.12.0 release. check-in: 6b199ba3e1 user: mistachkin tags: trunk
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Changes to Doc/Extra/Core/pragma.html.

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    that SQLite will hold in memory at once per open database file.  Whether
    or not this suggestion is honored is at the discretion of the
    <a href="c3ref/pcache_methods2.html">Application Defined Page Cache</a>.
    The default page cache that is built into SQLite honors the request,
    however alternative application-defined page cache implementations
    may choose to interpret the suggested cache size in different ways
    or to ignore it all together.
    The default suggested cache size is 2000 pages.

    The default suggested cache size can be altered using the
    <a href="compile.html#default_cache_size">SQLITE_DEFAULT_CACHE_SIZE</a> compile-time options.
    The TEMP database has a default suggested cache size of 0 pages.</p>

    <p>If the argument N is positive then the suggested cache size is set 
    to N. If the argument N is negative, then the
    number of cache pages is adjusted to use approximately abs(N*1024) bytes
................................................................................
<hr>
   <p><b>PRAGMA </b><i>schema.</i><b>page_size;
       <br>PRAGMA </b><i>schema.</i><b>page_size = </b><i>bytes</i><b>;</b></p>
    <p>Query or set the page size of the database. The page
    size must be a power of two between 512 and 65536 inclusive.
    </p>

    <p>When a new database is created, SQLite assigned a default page size
    based on information received from the xSectorSize and 
    xDeviceCharacteristics methods of the <a href="c3ref/io_methods.html">sqlite3_io_methods</a> object
    of the newly created database file.  The page_size pragma will only


    cause an immediate change in the
    page size if it is issued while the database is still empty, prior 
    to the first CREATE TABLE statement.  If the page_size pragma is
    used to specify a new page size just prior to
    running the <a href="lang_vacuum.html">VACUUM</a> command and if the database is not in
    <a href="wal.html">WAL journal mode</a> then <a href="lang_vacuum.html">VACUUM</a> will change the page
    size to the new value.</p>

    <p>If SQLite is compiled with the SQLITE_ENABLE_ATOMIC_WRITE option,
    then the default page size is chosen to be the largest page size
    less than or equal to SQLITE_MAX_DEFAULT_PAGE_SIZE for which atomic
    write is enabled according to the
    xDeviceCharacteristics method of the <a href="c3ref/io_methods.html">sqlite3_io_methods</a> object for
    the database file.  If the SQLITE_ENABLE_ATOMIC_WRITE option is
    disabled or if xDeviceCharacteristics reports no suitable atomic
    write page sizes, then the default page size is the larger of 
    SQLITE_DEFAULT_PAGE_SIZE
    and the sector size as reported by the xSectorSize method of the
    <a href="c3ref/io_methods.html">sqlite3_io_methods</a> object, but not more than 
    SQLITE_MAX_DEFAULT_PAGE_SIZE.  The normal configuration for SQLite
    running on workstations is for atomic write to be
    disabled, for the maximum page size to be set to 65536, for
    SQLITE_DEFAULT_PAGE_SIZE to be 1024, and for the
    maximum default page size to be set to 8192.  The default xSectorSize
    method on unix workstation implementations always reports a sector size
    of 512 bytes.  Hence, 
    the default page size chosen by SQLite on unix is usually 1024 bytes.
    On windows, the GetDiskFreeSpace() interface is used to obtain the
    actual device sector size and hence the default page size on windows
    will sometimes be greater than 1024.</p>
<a name="pragma_parser_trace"></a>
<hr>
    <p><b>PRAGMA parser_trace = </b><i>boolean</i><b>; </b></p>

    <p>If SQLite has been compiled with the <a href="compile.html#debug">SQLITE_DEBUG</a> compile-time
    option, then the parser_trace pragma can be used to turn on tracing
    for the SQL parser used internally by SQLite.
................................................................................
    <dd>
    When synchronous is FULL (2), the SQLite database engine will
    use the xSync method of the <a href="vfs.html">VFS</a> to ensure that all content is safely
    written to the disk surface prior to continuing.
    This ensures that an operating system crash or power failure will
    not corrupt the database.
    FULL synchronous is very safe, but it is also slower.  FULL is the
    usual default setting when not in <a href="wal.html">WAL mode</a>.</dd>
    <dt><b>NORMAL</b> (1)</dt>
    <dd>
    When synchronous is NORMAL (1), the SQLite database
    engine will still sync at the most critical moments, but less often
    than in FULL mode.  There is a very small (though non-zero) chance that
    a power failure at just the wrong time could corrupt the database in
    NORMAL mode.  But in practice, you are more likely to suffer
    a catastrophic disk failure or some other unrecoverable hardware
    fault.  NORMAL is the default when in <a href="wal.html">WAL mode</a>.</dd>
    <dt><b>OFF</b> (0)</dt>
    <dd>
    With synchronous OFF (0), SQLite continues without syncing
    as soon as it has handed data off to the operating system.
    If the application running SQLite crashes, the data will be safe, but
    the database might become corrupted if the operating system
    crashes or the computer loses power before that data has been written
................................................................................
    sync operation of the WAL file happens after each transaction commit.
    The extra WAL sync following each transaction help ensure that 
    transactions are durable across a power loss, but they do not aid
    in preserving consistency.
    If durability is not a concern, then synchronous=NORMAL is normally
    all one needs in WAL mode.</p>

    <p>The default setting is usually synchronous=FULL, 
    except in <a href="wal.html">WAL mode</a> when the default is synchronous=NORMAL.
    The <a href="compile.html#extra_durable">SQLITE_EXTRA_DURABLE</a> compile-time option changes the
    default to synchronous=EXTRA.</p>

    <p>See also the <a href="pragma.html#pragma_fullfsync">fullfsync</a> and <a href="pragma.html#pragma_checkpoint_fullfsync">checkpoint_fullfsync</a> pragmas.</p>
<a name="pragma_table_info"></a>
<hr>
    <p><b>PRAGMA </b><i>schema.</i><b>table_info(</b><i>table-name</i><b>);</b></p>







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    that SQLite will hold in memory at once per open database file.  Whether
    or not this suggestion is honored is at the discretion of the
    <a href="c3ref/pcache_methods2.html">Application Defined Page Cache</a>.
    The default page cache that is built into SQLite honors the request,
    however alternative application-defined page cache implementations
    may choose to interpret the suggested cache size in different ways
    or to ignore it all together.
    The default suggested cache size is -2000, which means the cache size
    is limited to 2048000 bytes of memory.
    The default suggested cache size can be altered using the
    <a href="compile.html#default_cache_size">SQLITE_DEFAULT_CACHE_SIZE</a> compile-time options.
    The TEMP database has a default suggested cache size of 0 pages.</p>

    <p>If the argument N is positive then the suggested cache size is set 
    to N. If the argument N is negative, then the
    number of cache pages is adjusted to use approximately abs(N*1024) bytes
................................................................................
<hr>
   <p><b>PRAGMA </b><i>schema.</i><b>page_size;
       <br>PRAGMA </b><i>schema.</i><b>page_size = </b><i>bytes</i><b>;</b></p>
    <p>Query or set the page size of the database. The page
    size must be a power of two between 512 and 65536 inclusive.
    </p>

    <p>When a new database is created, SQLite assigned a page size to
    the database based on platform and filesystem.  For many years,
    the default page size was almost always 1024 bytes, but beginning
    with SQLite <a href="releaselog/3_12_0.html">version 3.12.0</a> in 2016, the default page size increased
    to 4096.

    <p>The page_size pragma will only cause an immediate change in the
    page size if it is issued while the database is still empty, prior 
    to the first CREATE TABLE statement.  If the page_size pragma is
    used to specify a new page size just prior to
    running the <a href="lang_vacuum.html">VACUUM</a> command and if the database is not in
    <a href="wal.html">WAL journal mode</a> then <a href="lang_vacuum.html">VACUUM</a> will change the page
    size to the new value.</p>









    <p>The <a href="compile.html#default_page_size">SQLITE_DEFAULT_PAGE_SIZE</a> compile-time option can be used











    to change the default page size assigned to new databases.

<a name="pragma_parser_trace"></a>
<hr>
    <p><b>PRAGMA parser_trace = </b><i>boolean</i><b>; </b></p>

    <p>If SQLite has been compiled with the <a href="compile.html#debug">SQLITE_DEBUG</a> compile-time
    option, then the parser_trace pragma can be used to turn on tracing
    for the SQL parser used internally by SQLite.
................................................................................
    <dd>
    When synchronous is FULL (2), the SQLite database engine will
    use the xSync method of the <a href="vfs.html">VFS</a> to ensure that all content is safely
    written to the disk surface prior to continuing.
    This ensures that an operating system crash or power failure will
    not corrupt the database.
    FULL synchronous is very safe, but it is also slower.  FULL is the
    most commonly used synchronous setting when not in <a href="wal.html">WAL mode</a>.</dd>
    <dt><b>NORMAL</b> (1)</dt>
    <dd>
    When synchronous is NORMAL (1), the SQLite database
    engine will still sync at the most critical moments, but less often
    than in FULL mode.  There is a very small (though non-zero) chance that
    a power failure at just the wrong time could corrupt the database in
    NORMAL mode.  But in practice, you are more likely to suffer
    a catastrophic disk failure or some other unrecoverable hardware
    fault.  Many applications choose NORMAL when in <a href="wal.html">WAL mode</a>.</dd>
    <dt><b>OFF</b> (0)</dt>
    <dd>
    With synchronous OFF (0), SQLite continues without syncing
    as soon as it has handed data off to the operating system.
    If the application running SQLite crashes, the data will be safe, but
    the database might become corrupted if the operating system
    crashes or the computer loses power before that data has been written
................................................................................
    sync operation of the WAL file happens after each transaction commit.
    The extra WAL sync following each transaction help ensure that 
    transactions are durable across a power loss, but they do not aid
    in preserving consistency.
    If durability is not a concern, then synchronous=NORMAL is normally
    all one needs in WAL mode.</p>

    <p>The default setting is usually synchronous=FULL.

    The <a href="compile.html#extra_durable">SQLITE_EXTRA_DURABLE</a> compile-time option changes the
    default to synchronous=EXTRA.</p>

    <p>See also the <a href="pragma.html#pragma_fullfsync">fullfsync</a> and <a href="pragma.html#pragma_checkpoint_fullfsync">checkpoint_fullfsync</a> pragmas.</p>
<a name="pragma_table_info"></a>
<hr>
    <p><b>PRAGMA </b><i>schema.</i><b>table_info(</b><i>table-name</i><b>);</b></p>