doc/src/sgml/ref/drop_subscription.sgml - master - githubmirror/postgres

doc/src/sgml/ref/drop_subscription.sgml
156 строк5 KB
Amit Kapila
Doc: Clarify DROP SUBSCRIPTION behavior after SET (slot_name = NONE).
17 июл 2026, 07:17
17 июл 2026, 07:170348090
<!--
doc/src/sgml/ref/drop_subscription.sgml
PostgreSQL documentation
-->

<refentry id="sql-dropsubscription">
 <indexterm zone="sql-dropsubscription">
  <primary>DROP SUBSCRIPTION</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>DROP SUBSCRIPTION</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>DROP SUBSCRIPTION</refname>
  <refpurpose>remove a subscription</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
DROP SUBSCRIPTION [ IF EXISTS ] <replaceable class="parameter">name</replaceable> [ CASCADE | RESTRICT ]
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>DROP SUBSCRIPTION</command> removes a subscription from the
   database cluster.
  </para>

  <para>
   To execute this command the user must be the owner of the subscription.
  </para>

  <para>
   <command>DROP SUBSCRIPTION</command> cannot be executed inside a
   transaction block if the subscription is associated with a replication
   slot.  (You can use <link linkend="sql-altersubscription"><command>ALTER SUBSCRIPTION</command></link> to unset the
   slot.)
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><literal>IF EXISTS</literal></term>
    <listitem>
     <para>
      Do not throw an error if the subscription does not exist. A notice is
      issued in this case.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">name</replaceable></term>
    <listitem>
     <para>
      The name of a subscription to be dropped.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>CASCADE</literal></term>
    <term><literal>RESTRICT</literal></term>

    <listitem>
     <para>
      These key words do not have any effect, since there are no dependencies
      on subscriptions.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   When dropping a subscription that is associated with a replication slot on
   the remote host (the normal state), <command>DROP SUBSCRIPTION</command>
   will connect to the remote host and try to drop the replication slot (and
   any remaining table synchronization slots) as
   part of its operation.  This is necessary so that the resources allocated
   for the subscription on the remote host are released.  If this fails,
   either because the remote host is not reachable or because the remote
   replication slot cannot be dropped or does not exist or never existed,
   the <command>DROP SUBSCRIPTION</command> command will fail.  To proceed
   in this situation, first disable the subscription by executing
   <link linkend="sql-altersubscription-params-disable">
   <literal>ALTER SUBSCRIPTION ... DISABLE</literal></link>, and then disassociate
   it from the replication slot by executing
   <link linkend="sql-altersubscription-params-set">
   <literal>ALTER SUBSCRIPTION ... SET (slot_name = NONE)</literal></link>.
   After that, <command>DROP SUBSCRIPTION</command> will not attempt to drop
   the subscription's own replication slot.  It may still connect to the publisher
   to drop internally-created table synchronization slots if some table
   synchronization is left unfinished; if the publisher is unreachable, those
   slots (and the main slot, if it still exists) must be dropped manually.  Otherwise
   it/they will continue to reserve WAL and might eventually cause the disk to
   fill up.  See also
   <xref linkend="logical-replication-subscription-slot"/>.
  </para>

  <para>
   If a subscription is associated with a replication slot, then <command>DROP
   SUBSCRIPTION</command> cannot be executed inside a transaction block.
  </para>

  <para>
   If a conflict log table exists for the subscription (that is, when
   <link linkend="sql-createsubscription-params-with-conflict-log-destination">
   <literal>conflict_log_destination</literal></link> is set to <literal>table</literal>
   or <literal>all</literal>), <command>DROP SUBSCRIPTION</command> automatically drops
   the associated conflict log table.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Drop a subscription:
<programlisting>
DROP SUBSCRIPTION mysub;
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   <command>DROP SUBSCRIPTION</command> is a <productname>PostgreSQL</productname>
   extension.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-createsubscription"/></member>
   <member><xref linkend="sql-altersubscription"/></member>
  </simplelist>
 </refsect1>
</refentry>