PostgreSQL/doc/src/sgml/ref/checkpoint.sgml
Robert Haas c53d3a9ee1 Make the CHECKPOINT reference page more clear.
Josh Kupershmidt, reviewed by Fujii Masao
2011-10-18 20:14:51 -04:00

65 lines
1.7 KiB
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<!-- doc/src/sgml/ref/checkpoint.sgml -->
<refentry id="sql-checkpoint">
<refmeta>
<refentrytitle>CHECKPOINT</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>CHECKPOINT</refname>
<refpurpose>force a transaction log checkpoint</refpurpose>
</refnamediv>
<indexterm zone="sql-checkpoint">
<primary>CHECKPOINT</primary>
</indexterm>
<refsynopsisdiv>
<synopsis>
CHECKPOINT
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
A checkpoint is a point in the transaction log sequence at which
all data files have been updated to reflect the information in the
log. All data files will be flushed to disk. Refer to
<xref linkend="wal-configuration"> for more details about what happens
during a checkpoint.
</para>
<para>
The <command>CHECKPOINT</command> command forces an immediate
checkpoint when the command is issued, without waiting for a
regular checkpoint scheduled by the system (controlled by the settings in
<xref linkend="runtime-config-wal-checkpoints">).
<command>CHECKPOINT</command> is not intended for use during normal
operation.
</para>
<para>
If executed during recovery, the <command>CHECKPOINT</command> command
will force a restartpoint (see <xref linkend="wal-configuration">)
rather than writing a new checkpoint.
</para>
<para>
Only superusers can call <command>CHECKPOINT</command>.
</para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
The <command>CHECKPOINT</command> command is a
<productname>PostgreSQL</productname> language extension.
</para>
</refsect1>
</refentry>