$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.210 2004/06/24 19:57:14 tgl Exp $

<indexterm zone="functions-misc">

<primary>pg_cancel_backend</primary>

</indexterm>

<indexterm zone="functions-misc">

<primary>pg_terminate_backend</primary>

</indexterm>

<indexterm zone="functions-misc">

<primary>signal</primary>

<secondary sortas="backend">backend processes</secondary>

</indexterm>

<para>

The functions shown in <xref

linkend="functions-misc-signal-table"> send control signals to

other server processes. Use of these functions is restricted

to superusers.

</para>

<table id="functions-misc-signal-table">

<title>Backend Signalling Functions</title>

<tgroup cols="3">

<thead>

<row><entry>Name</entry> <entry>Return Type</entry> <entry>Description</entry>

</row>

</thead>

<tbody>

<row>

<entry>

<literal><function>pg_cancel_backend</function>(<parameter>pid</parameter>)</literal>

</entry>

<entry><type>int</type></entry>

<entry>Cancel a backend's current query</entry>

</row>

<row>

<entry>

<literal><function>pg_terminate_backend</function>(<parameter>pid</parameter>)</literal>

</entry>

<entry><type>int</type></entry>

<entry>Terminate a backend process</entry>

</row>

</tbody>

</tgroup>

</table>

<para>

These functions return 1 if successful, 0 if not successful.

The process ID (<literal>pid</literal>) of an active backend can be found

from the <structfield>procpid</structfield> column in the

<structname>pg_stat_activity</structname> view, or by listing the postgres

processes on the server.

</para>