<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >CHECKPOINT</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 8.0.11 Documentation" HREF="index.html"><LINK REL="UP" TITLE="SQL Commands" HREF="sql-commands.html"><LINK REL="PREVIOUS" TITLE="BEGIN" HREF="sql-begin.html"><LINK REL="NEXT" TITLE="CLOSE" HREF="sql-close.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2007-02-02T03:57:22"></HEAD ><BODY CLASS="REFENTRY" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-begin.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-begin.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-close.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-close.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SQL-CHECKPOINT" ></A >CHECKPOINT</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN37872" ></A ><H2 >Name</H2 >CHECKPOINT -- force a transaction log checkpoint</DIV ><A NAME="AEN37875" ></A ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN37877" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >CHECKPOINT</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN37879" ></A ><H2 >Description</H2 ><P > Write-Ahead Logging (WAL) puts a checkpoint in the transaction log every so often. (To adjust the automatic checkpoint interval, see the run-time configuration options <A HREF="runtime-config.html#GUC-CHECKPOINT-SEGMENTS" >checkpoint_segments</A > and <A HREF="runtime-config.html#GUC-CHECKPOINT-TIMEOUT" >checkpoint_timeout</A >.) The <TT CLASS="COMMAND" >CHECKPOINT</TT > command forces an immediate checkpoint when the command is issued, without waiting for a scheduled checkpoint. </P ><P > 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 <A HREF="wal.html" >Chapter 25</A > for more information about the WAL system. </P ><P > Only superusers may call <TT CLASS="COMMAND" >CHECKPOINT</TT >. The command is not intended for use during normal operation. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN37889" ></A ><H2 >Compatibility</H2 ><P > The <TT CLASS="COMMAND" >CHECKPOINT</TT > command is a <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > language extension. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sql-begin.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sql-close.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >BEGIN</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >CLOSE</TD ></TR ></TABLE ></DIV ></BODY ></HTML >