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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>27.1. Archive Recovery Settings</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="recovery-config.html" title="Chapter 27. Recovery Configuration" /><link rel="next" href="recovery-target-settings.html" title="27.2. Recovery Target Settings" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">27.1. Archive Recovery Settings</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="recovery-config.html" title="Chapter 27. Recovery Configuration">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="recovery-config.html" title="Chapter 27. Recovery Configuration">Up</a></td><th width="60%" align="center">Chapter 27. Recovery Configuration</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="recovery-target-settings.html" title="27.2. Recovery Target Settings">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="ARCHIVE-RECOVERY-SETTINGS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">27.1. Archive Recovery Settings</h2></div></div></div><div class="variablelist"><dl class="variablelist"><dt id="RESTORE-COMMAND"><span class="term"><code class="varname">restore_command</code> (<code class="type">string</code>)
<a id="id-1.6.14.6.2.1.1.3" class="indexterm"></a>
</span></dt><dd><p>
The local shell command to execute to retrieve an archived segment of
the WAL file series. This parameter is required for archive recovery,
but optional for streaming replication.
Any <code class="literal">%f</code> in the string is
replaced by the name of the file to retrieve from the archive,
and any <code class="literal">%p</code> is replaced by the copy destination path name
on the server.
(The path name is relative to the current working directory,
i.e., the cluster's data directory.)
Any <code class="literal">%r</code> is replaced by the name of the file containing the
last valid restart point. That is the earliest file that must be kept
to allow a restore to be restartable, so this information can be used
to truncate the archive to just the minimum required to support
restarting from the current restore. <code class="literal">%r</code> is typically only
used by warm-standby configurations
(see <a class="xref" href="warm-standby.html" title="26.2. Log-Shipping Standby Servers">Section 26.2</a>).
Write <code class="literal">%%</code> to embed an actual <code class="literal">%</code> character.
</p><p>
It is important for the command to return a zero exit status
only if it succeeds. The command <span class="emphasis"><em>will</em></span> be asked for file
names that are not present in the archive; it must return nonzero
when so asked. Examples:
</p><pre class="programlisting">
restore_command = 'cp /mnt/server/archivedir/%f "%p"'
restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</pre><p>
An exception is that if the command was terminated by a signal (other
than <span class="systemitem">SIGTERM</span>, which is used as part of a
database server shutdown) or an error by the shell (such as command
not found), then recovery will abort and the server will not start up.
</p></dd><dt id="ARCHIVE-CLEANUP-COMMAND"><span class="term"><code class="varname">archive_cleanup_command</code> (<code class="type">string</code>)
<a id="id-1.6.14.6.2.2.1.3" class="indexterm"></a>
</span></dt><dd><p>
This optional parameter specifies a shell command that will be executed
at every restartpoint. The purpose of
<code class="varname">archive_cleanup_command</code> is to provide a mechanism for
cleaning up old archived WAL files that are no longer needed by the
standby server.
Any <code class="literal">%r</code> is replaced by the name of the file containing the
last valid restart point.
That is the earliest file that must be <span class="emphasis"><em>kept</em></span> to allow a
restore to be restartable, and so all files earlier than <code class="literal">%r</code>
may be safely removed.
This information can be used to truncate the archive to just the
minimum required to support restart from the current restore.
The <a class="xref" href="pgarchivecleanup.html" title="pg_archivecleanup"><span class="refentrytitle"><span class="application">pg_archivecleanup</span></span></a> module
is often used in <code class="varname">archive_cleanup_command</code> for
single-standby configurations, for example:
</p><pre class="programlisting">archive_cleanup_command = 'pg_archivecleanup /mnt/server/archivedir %r'</pre><p>
Note however that if multiple standby servers are restoring from the
same archive directory, you will need to ensure that you do not delete
WAL files until they are no longer needed by any of the servers.
<code class="varname">archive_cleanup_command</code> would typically be used in a
warm-standby configuration (see <a class="xref" href="warm-standby.html" title="26.2. Log-Shipping Standby Servers">Section 26.2</a>).
Write <code class="literal">%%</code> to embed an actual <code class="literal">%</code> character in the
command.
</p><p>
If the command returns a nonzero exit status then a warning log
message will be written. An exception is that if the command was
terminated by a signal or an error by the shell (such as command not
found), a fatal error will be raised.
</p></dd><dt id="RECOVERY-END-COMMAND"><span class="term"><code class="varname">recovery_end_command</code> (<code class="type">string</code>)
<a id="id-1.6.14.6.2.3.1.3" class="indexterm"></a>
</span></dt><dd><p>
This parameter specifies a shell command that will be executed once only
at the end of recovery. This parameter is optional. The purpose of the
<code class="varname">recovery_end_command</code> is to provide a mechanism for cleanup
following replication or recovery.
Any <code class="literal">%r</code> is replaced by the name of the file containing the
last valid restart point, like in <a class="xref" href="archive-recovery-settings.html#ARCHIVE-CLEANUP-COMMAND">archive_cleanup_command</a>.
</p><p>
If the command returns a nonzero exit status then a warning log
message will be written and the database will proceed to start up
anyway. An exception is that if the command was terminated by a
signal or an error by the shell (such as command not found), the
database will not proceed with startup.
</p></dd></dl></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="recovery-config.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="recovery-config.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="recovery-target-settings.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 27. Recovery Configuration </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 27.2. Recovery Target Settings</td></tr></table></div></body></html>
