<!-- $PostgreSQL: pgsql/doc/src/sgml/pgarchivecleanup.sgml,v 1.1.2.3 2010/08/17 04:37:17 petere Exp $ -->

<sect1 id="pgarchivecleanup">
 <title>pg_archivecleanup</title>

 <indexterm zone="pgarchivecleanup">
  <primary>pg_archivecleanup</primary>
 </indexterm>

 <para>
  <application>pg_archivecleanup</> is designed to be used as an
  <literal>archive_cleanup_command</literal> to clean up WAL file archives when
  running as a standby server (see <xref linkend="warm-standby">).
  <application>pg_archivecleanup</> can also be used as a standalone program to
  clean WAL file archives.
 </para>

 <para>
  <application>pg_archivecleanup</application> features include:
 </para>
 <itemizedlist>
  <listitem>
   <para>
    Written in C, so very portable and easy to install
   </para>
  </listitem>
  <listitem>
   <para>
    Easy-to-modify source code, with specifically designated
    sections to modify for your own needs
   </para>
  </listitem>
 </itemizedlist>

 <sect2>
  <title>Usage</title>

  <para>
   To configure a standby
   server to use <application>pg_archivecleanup</>, put this into its
   <filename>recovery.conf</filename> configuration file:
<programlisting>
archive_cleanup_command = 'pg_archivecleanup <replaceable>archivelocation</> %r'
</programlisting>
   where <replaceable>archivelocation</> is the directory from which WAL segment
   files should be removed.
  </para>
  <para>
   When used within <xref linkend="archive-cleanup-command">, all WAL files
   logically preceding the value of the <literal>%r</> argument will be removed
   from <replaceable>archivelocation</>. This minimizes the number of files
   that need to be retained, while preserving crash-restart capability.  Use of
   this parameter is appropriate if the <replaceable>archivelocation</> is a
   transient staging area for this particular standby server, but
   <emphasis>not</> when the <replaceable>archivelocation</> is intended as a
   long-term WAL archive area, or when multiple standby servers are recovering
   from the same archive location.
  </para>
  <para>
   The full syntax of <application>pg_archivecleanup</>'s command line is
<synopsis>
pg_archivecleanup <optional> <replaceable>option</> ... </optional> <replaceable>archivelocation</> <replaceable>restartwalfile</>
</synopsis>
   When used as a standalone program all WAL files logically preceding the 
   <literal>restartwalfile</> will be removed <replaceable>archivelocation</>.
   In this mode, if you specify a <filename>.backup</> file name, then only the file prefix
   will be used as the <literal>restartwalfile</>. This allows you to remove
   all WAL files archived prior to a specific base backup without error.
   For example, the following example will remove all files older than
   WAL file name <filename>000000010000003700000010</>:
<programlisting>
pg_archivecleanup -d archive 000000010000003700000010.00000020.backup

pg_archivecleanup:  keep WAL file "archive/000000010000003700000010" and later
pg_archivecleanup:  removing file "archive/00000001000000370000000F"
pg_archivecleanup:  removing file "archive/00000001000000370000000E"
</programlisting>
   <application>pg_archivecleanup</application> assumes that
   <replaceable>archivelocation</> is a directory readable and writable by the
   server-owning user.
  </para>
 </sect2>

 <sect2>
  <title><application>pg_archivecleanup</> Options</title>

   <para>
    <application>pg_archivecleanup</application> accepts the following command-line arguments:

    <variablelist>

     <varlistentry>
      <term><option>-d</option></term>
      <listitem>
       <para>
        Print lots of debug logging output on <filename>stderr</>.
       </para>
      </listitem>
     </varlistentry>

    </variablelist>
   </para>

 </sect2>

 <sect2>
  <title>Examples</title>

  <para>On Linux or Unix systems, you might use:
<programlisting>
archive_cleanup_command = 'pg_archivecleanup -d /mnt/standby/archive %r 2>>cleanup.log'
</programlisting>
   where the archive directory is physically located on the standby server,
   so that the <literal>archive_command</> is accessing it across NFS,
   but the files are local to the standby.
   This will:
  </para>
  <itemizedlist>
   <listitem>
    <para>
     produce debugging output in <filename>cleanup.log</>
    </para>
   </listitem>
   <listitem>
    <para>
     remove no-longer-needed files from the archive directory
    </para>
   </listitem>
  </itemizedlist>

 </sect2>

 <sect2>
  <title>Supported server versions</title>

  <para>
   <application>pg_archivecleanup</application> is designed to work with
   <productname>PostgreSQL</> 8.0 and later when used as a standalone utility,
   or with <productname>PostgreSQL</> 9.0 and later when used as an
   archive cleanup command.
  </para>
 </sect2>

 <sect2>
  <title>Author</title>

  <para>
   Simon Riggs <email>simon@2ndquadrant.com</email>
  </para>
 </sect2>

</sect1>
