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<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/clean_connection.sgml,v 1.50 2010/04/03 07:22:59 petere Exp $
PostgreSQL documentation
-->
<refentry id="SQL-CLEANCONNECTION">
<indexterm zone="sql-cleanconnection">
<primary>CLEAN CONNECTION</primary>
</indexterm>
<refmeta>
<refentrytitle>CLEAN CONNECTION</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>CLEAN CONNECTION</refname>
<refpurpose>Clean up pooler connections in a cluster</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis>
CLEAN CONNECTION TO { COORDINATOR ( <replaceable class="parameter">nodename</replaceable> [, ... ] ) | NODE ( <replaceable class="parameter">nodename</replaceable> [, ... ] ) | ALL {FORCE} }
[ FOR DATABASE <replaceable class="parameter">dbname</replaceable> ]
[ TO USER <replaceable class="parameter">username</replaceable> ]
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>CLEAN CONNECTION</command> cleans pooler connections in
a Postgres-XL cluster. This can be done for a given database or
role. This command's usage is restricted to superusers. It is
possible to clean connections to a list of Postgres-XL Coordinators
or Datanodes. If TO ALL is specified, connections to all the nodes
are cleaned. A <replaceable class="parameter">username</replaceable>
or a <replaceable class="parameter">dbname</replaceable> has to be
specified to perform <command>CLEAN CONNECTION</command>.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><literal>FORCE</literal></term>
<listitem>
<para>
It can only be specified with the clause <literal>TO ALL</literal>.
If specified, all the backends connected to the specified node(s)
are closed by sending to them a signal SIGTERM.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">dbname</replaceable></term>
<listitem>
<para>
If specified in the optional clause <literal>FOR DATABASE</literal>,
pooler connections are cleaned for given database.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">username</replaceable></term>
<listitem>
<para>
If specified in the optional clause <literal>TO USER</literal>, pooler
connections are cleaned for the given role.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">nodename</replaceable></term>
<listitem>
<para>
In the case of cleaning connections to a given list of Coordinators,
<replaceable class="parameter">nodename</replaceable> has to be specified
with the clause <literal>TO COORDINATOR </literal>.
</para>
<para>
In the case of cleaning connections to a given list of
Datanodes, <replaceable class="parameter">nodename</replaceable>
has to be specified with the clause <literal>TO NODE
</literal>.
</para>
<para>
<replaceable class="parameter">num</replaceable> can contain
a list of nodes like in the query:
<programlisting>
CLEAN CONNECTION TO COORDINATOR coord1,coord2 FOR DATABASE<replaceable>name</replaceable>;
</programlisting>
to clean connections to Coordinators coord1 and coord2.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
Cleaning connection to Datanodes dn1 and dn2 for database template1:
<programlisting>
CLEAN CONNECTION TO NODE dn1,dn2 FOR DATABASE template1;
</programlisting>
</para>
<para>
Cleaning connection to Datanode dn3 for role postgres:
<programlisting>
CLEAN CONNECTION TO NODE dn3 TO USER postgres;
</programlisting>
</para>
<para>
Cleaning connection to all nodes on database postgres for
role admin and cut connections to backends.
<programlisting>
CLEAN CONNECTION TO ALL FORCE FOR DATABASE postgres TO USER admin;
</programlisting>
</para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
<command>CLEAN CONNECTION</command> does not conform to the <acronym>
SQL</acronym> standards, it is a Postgres-XL specific command.
</para>
</refsect1>
</refentry>
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