<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/pg_controldata.sgml,v 1.9 2007/01/31 23:26:04 momjian Exp $
PostgreSQL documentation
-->

<refentry id="APP-PGCONTROLDATA">
 <refmeta>
  <refentrytitle id="APP-PGCONTROLDATA-TITLE"><application>pg_controldata</application></refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo>Application</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>pg_controldata</refname>
  <refpurpose>display control information of a <productname>PostgreSQL</productname> database cluster</refpurpose>
 </refnamediv>

 <indexterm zone="app-pgcontroldata">
  <primary>pg_controldata</primary>
 </indexterm>

 <refsynopsisdiv>
  <cmdsynopsis>
   <command>pg_controldata</command>
   <arg><replaceable class="parameter">datadir</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>

 <refsect1 id="R1-APP-PGCONTROLDATA-1">
  <title>Description</title>
  <para>
   <command>pg_controldata</command> prints information initialized during
   <command>initdb</>, such as the catalog version and server locale.
   It also shows information about write-ahead logging and checkpoint 
   processing.  This information is cluster-wide, and not specific to any one
   database.
  </para>

  <para>
   This utility can only be run by the user who initialized the cluster because
   it requires read access to the data directory.
   You can specify the data directory on the command line, or use 
   the environment variable <envar>PGDATA</>.
  </para>
 </refsect1>

 <refsect1>
  <title>Environment</title>

  <variablelist>
   <varlistentry>
    <term><envar>PGDATA</envar></term>

    <listitem>
     <para>
      Default data directory location
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </refsect1>
</refentry>
