<!--
doc/src/sgml/ref/clusterdb.sgml
PostgreSQL documentation
-->
<refentry id="app-clusterdb">
<indexterm zone="app-clusterdb">
<primary>clusterdb</primary>
</indexterm>
<refmeta>
<refentrytitle><application>clusterdb</application></refentrytitle>
<manvolnum>1</manvolnum>
<refmiscinfo>Application</refmiscinfo>
</refmeta>
<refnamediv>
<refname>clusterdb</refname>
<refpurpose>cluster a <productname>PostgreSQL</productname> database</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>clusterdb</command>
<arg rep="repeat"><replaceable>connection-option</replaceable></arg>
<arg rep="repeat"><replaceable>option</replaceable></arg>
<arg choice="plain" rep="repeat">
<arg choice="opt">
<group choice="plain">
<arg choice="plain"><option>--table</option></arg>
<arg choice="plain"><option>-t</option></arg>
</group>
<replaceable>table</replaceable>
</arg>
</arg>
<arg choice="opt">
<group choice="plain">
<arg choice="plain"><replaceable>dbname</replaceable></arg>
<arg choice="plain"><option>-a</option></arg>
<arg choice="plain"><option>--all</option></arg>
</group>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<application>clusterdb</application> is a utility for reclustering tables
in a <productname>PostgreSQL</productname> database. It finds tables
that have previously been clustered, and clusters them again on the same
index that was last used. Tables that have never been clustered are not
affected.
</para>
<para>
<application>clusterdb</application> is a wrapper around the SQL
command <xref linkend="sql-cluster"/>.
There is no effective difference between clustering databases via
this utility and via other methods for accessing the server.
</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>
<application>clusterdb</application> accepts the following command-line arguments:
<variablelist>
<varlistentry>
<term><option>-a</option></term>
<term><option>--all</option></term>
<listitem>
<para>
Cluster all databases.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option><optional>-d</optional> <replaceable class="parameter">dbname</replaceable></option></term>
<term><option><optional>--dbname=</optional><replaceable class="parameter">dbname</replaceable></option></term>
<listitem>
<para>
Specifies the name of the database to be clustered,
when <option>-a</option>/<option>--all</option> is not used.
If this is not specified, the database name is read
from the environment variable <envar>PGDATABASE</envar>. If
that is not set, the user name specified for the connection is
used. The <replaceable>dbname</replaceable> can be a <link
linkend="libpq-connstring">connection string</link>. If so,
connection string parameters will override any conflicting command
line options.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-e</option></term>
<term><option>--echo</option></term>
<listitem>
<para>
Echo the commands that <application>clusterdb</application> generates
and sends to the server.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-q</option></term>
<term><option>--quiet</option></term>
<listitem>
<para>
Do not display progress messages.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-t <replaceable class="parameter">table</replaceable></option></term>
<term><option>--table=<replaceable class="parameter">table</replaceable></option></term>
<listitem>
<para>
Cluster <replaceable class="parameter">table</replaceable>