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Comment:Clarifications in "PRAGMA synchronous".
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SHA1: 73e31a30966929633cc46b196e496afd25f9f1bb
User & Date: drh 2016-03-08 13:15:43
Context
2016-03-08
16:42
Update documentation for SQLITE_DEFAULT_SYNCHRONOUS and related changes. check-in: ab3cf23c74 user: drh tags: trunk
13:15
Clarifications in "PRAGMA synchronous". check-in: 73e31a3096 user: drh tags: trunk
13:11
Add documentation for the SQLITE_STMTJRNL_SPILL compile-time option. check-in: 0449652cda user: drh tags: trunk
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Changes to pages/pragma.in.

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    <dd>
    ^When synchronous is FULL (2), the SQLite database engine will
    use the xSync method of the [VFS] 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 [WAL mode].</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 [WAL mode].</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







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    <dd>
    ^When synchronous is FULL (2), the SQLite database engine will
    use the xSync method of the [VFS] 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 [WAL mode].</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 [WAL mode].</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