Documentation Source Text

<br clear="both">
<h2>5.0 Multi-file Commit</h2>

<p>SQLite allows a single 
<a href="c3ref/sqlite3.html">database connection</a> to talk to
two or more database files simultaneously through the use of
the <a href="/lang_attach.html">ATTACH DATABASE</a> command.
When multiple database files are modified within a single
transaction, all files are updated atomically.  
In other words, either all of the database files are updated or
else none of them are.
Achieving an atomic commit across multiple database files is
more complex that doing so for a single file.  This section
describes how SQLite works that bit of magic.</p>
................................................................................
dot-file locks or vice versa.</p>

<h3>9.2 Incomplete Disk Flushes</h3>

<p>SQLite uses the fsync() system call on unix and the FlushFileBuffers()
system call on w32 in order to sync the file system buffers onto disk
oxide as shown in  <a href="#section_3_7">step 3.7</a> and
<a href="#section_3.10">step 3.10</a>.  Unfortunately, we have received
reports that neither of these interfaces works as advertised on many
systems.  We hear that FlushFileBuffers() can be completely disabled
using registry settings on some windows versions.  Some historical
versions of Linux contain versions of fsync() which are no-ops on
some filesystems, we are told.  Even on systems where 
FlushFileBuffers() and fsync() are said to be working, often
the IDE disk control lies and says that data has reached oxide

<br clear="both">
<h2>5.0 Multi-file Commit</h2>

<p>SQLite allows a single 
<a href="c3ref/sqlite3.html">database connection</a> to talk to
two or more database files simultaneously through the use of
the <a href="lang_attach.html">ATTACH DATABASE</a> command.
When multiple database files are modified within a single
transaction, all files are updated atomically.  
In other words, either all of the database files are updated or
else none of them are.
Achieving an atomic commit across multiple database files is
more complex that doing so for a single file.  This section
describes how SQLite works that bit of magic.</p>
................................................................................
dot-file locks or vice versa.</p>

<h3>9.2 Incomplete Disk Flushes</h3>

<p>SQLite uses the fsync() system call on unix and the FlushFileBuffers()
system call on w32 in order to sync the file system buffers onto disk
oxide as shown in  <a href="#section_3_7">step 3.7</a> and
<a href="#section_3_10">step 3.10</a>.  Unfortunately, we have received
reports that neither of these interfaces works as advertised on many
systems.  We hear that FlushFileBuffers() can be completely disabled
using registry settings on some windows versions.  Some historical
versions of Linux contain versions of fsync() which are no-ops on
some filesystems, we are told.  Even on systems where 
FlushFileBuffers() and fsync() are said to be working, often
the IDE disk control lies and says that data has reached oxide

or compound.</p>

<p>The optional conflict-clause allows the specification of an alternative
constraint conflict resolution algorithm to use during this one command.
See the section titled
<a href="lang_conflict.html">ON CONFLICT</a> for additional information.
For compatibility with MySQL, the parser allows the use of the
single keyword <a href="lange_replace.html">REPLACE</a> as an 
alias for "INSERT OR REPLACE".
</p>

<tcl>
##############################################################################
Section {ON CONFLICT clause} conflict

or compound.</p>

<p>The optional conflict-clause allows the specification of an alternative
constraint conflict resolution algorithm to use during this one command.
See the section titled
<a href="lang_conflict.html">ON CONFLICT</a> for additional information.
For compatibility with MySQL, the parser allows the use of the
single keyword <a href="lang_replace.html">REPLACE</a> as an 
alias for "INSERT OR REPLACE".
</p>

<tcl>
##############################################################################
Section {ON CONFLICT clause} conflict