67 lines
1.8 KiB
Plaintext
67 lines
1.8 KiB
Plaintext
<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/checkpoint.sgml,v 1.3 2001/01/27 10:19:52 petere Exp $ -->
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<refentry id="sql-checkpoint">
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<docinfo>
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<date>2001-01-24</date>
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</docinfo>
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<refmeta>
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<refentrytitle id="sql-checkpoint-title">CHECKPOINT</refentrytitle>
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<refmiscinfo>SQL - Language Statements</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>CHECKPOINT</refname>
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<refpurpose>Force transaction log checkpoint</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<synopsis>
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CHECKPOINT
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</synopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>
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Write-Ahead Logging (WAL) puts a checkpoint in the transaction log
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every 300 seconds by default. (This may be changed by the run-time
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configuration option <parameter>CHECKPOINT_TIMEOUT</parameter>.)
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The <command>CHECKPOINT</command> command forces a checkpoint at
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the point at which the command is issued. The next automatic
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checkpoint will still happen after the original cycle expires.
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</para>
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<para>
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A checkpoint is a point in the transaction log sequence at which
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all data files have been updated to reflect the information in the
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log. All data files will be flushed to disk. Refer to the
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<citetitle>PostgreSQL Administrator's Guide</citetitle> for more
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information about the WAL system.
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</para>
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<para>
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Only superusers may call <command>CHECKPOINT</command>. The command is
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not intended for use during normal operation.
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</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citetitle>PostgreSQL Administrator's Guide</citetitle>
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</para>
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</refsect1>
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<refsect1>
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<title>Compatibility</title>
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<para>
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The <command>CHECKPOINT</command> command is a
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<productname>PostgreSQL</productname> language extension.
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</para>
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</refsect1>
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</refentry>
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