<!--
doc/src/sgml/ref/alter_subscription.sgml
PostgreSQL documentation
-->

<refentry id="sql-altersubscription">
 <indexterm zone="sql-altersubscription">
  <primary>ALTER SUBSCRIPTION</primary>
 </indexterm>

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

 <refnamediv>
  <refname>ALTER SUBSCRIPTION</refname>
  <refpurpose>change the definition of a subscription</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> CONNECTION '<replaceable>conninfo</replaceable>'
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> SET PUBLICATION <replaceable class="parameter">publication_name</replaceable> [, ...] [ WITH ( <replaceable class="parameter">publication_option</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> ADD PUBLICATION <replaceable class="parameter">publication_name</replaceable> [, ...] [ WITH ( <replaceable class="parameter">publication_option</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> DROP PUBLICATION <replaceable class="parameter">publication_name</replaceable> [, ...] [ WITH ( <replaceable class="parameter">publication_option</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> REFRESH PUBLICATION [ WITH ( <replaceable class="parameter">refresh_option</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> ENABLE
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> DISABLE
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> SET ( <replaceable class="parameter">subscription_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_ROLE | CURRENT_USER | SESSION_USER }
ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> RENAME TO <replaceable>new_name</replaceable>
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER SUBSCRIPTION</command> can change most of the subscription
   properties that can be specified
   in <xref linkend="sql-createsubscription"/>.
  </para>

  <para>
   You must own the subscription to use <command>ALTER SUBSCRIPTION</command>.
   To alter the owner, you must also be a direct or indirect member of the
   new owning role. The new owner has to be a superuser.
   (Currently, all subscription owners must be superusers, so the owner checks
   will be bypassed in practice.  But this might change in the future.)
  </para>
  
  <para>
   When refreshing a publication we remove the relations that are no longer
   part of the publication and we also remove the table synchronization slots
   if there are any. It is necessary to remove these slots so that the resources
   allocated for the subscription on the remote host are released. If due to
   network breakdown or some other error, <productname>PostgreSQL</productname>
   is unable to remove the slots, an ERROR will be reported. To proceed in this
   situation, the user either needs to retry the operation or disassociate the
   slot from the subscription and drop the subscription as explained in
   <xref linkend="sql-dropsubscription"/>.
  </para>

  <para>
   Commands <command>ALTER SUBSCRIPTION ... REFRESH PUBLICATION</command> and
   <command>ALTER SUBSCRIPTION ... {SET|ADD|DROP} PUBLICATION ...</command> with refresh
   option as true cannot be executed inside a transaction block.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="parameter">name</replaceable></term>
    <listitem>
     <para>
      The name of a subscription whose properties are to be altered.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>CONNECTION '<replaceable class="parameter">conninfo</replaceable>'</literal></term>
    <listitem>
     <para>
      This clause alters the connection property originally set by
      <xref linkend="sql-createsubscription"/>.  See there for more
      information.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>SET PUBLICATION <replaceable class="parameter">publication_name</replaceable></literal></term>
    <term><literal>ADD PUBLICATION <replaceable class="parameter">publication_name</replaceable></literal></term>
    <term><literal>DROP PUBLICATION <replaceable class="parameter">publication_name</replaceable></literal></term>
    <listitem>
     <para>
      Changes the list of subscribed publications.  <literal>SET</literal>
      replaces the entire list of publications with a new list,
      <literal>ADD</literal> adds additional publications to the list of
      publications, and <literal>DROP</literal> removes the publications from
      the list of publications.  See <xref linkend="sql-createsubscription"/>
      for more information.  By default, this command will also act like
      <literal>REFRESH PUBLICATION</literal>, except that in case of
      <literal>ADD</literal> or <literal>DROP</literal>, only the added or
      dropped publications are refreshed.
     </para>

     <para>
      <replaceable>publication_option</replaceable> specifies additional
      options for this operation.  The supported options are:

      <variablelist>
       <varlistentry>
        <term><literal>refresh</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          When false, the command will not try to refresh table information.
          <literal>REFRESH PUBLICATION</literal> should then be executed separately.
          The default is <literal>true</literal>.
         </para>
        </listitem>
       </varlistentry>
      </variablelist>

      Additionally, refresh options as described
      under <literal>REFRESH PUBLICATION</literal> may be specified,
      except in the case of <literal>DROP PUBLICATION</literal>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>REFRESH PUBLICATION</literal></term>
    <listitem>
     <para>
      Fetch missing table information from publisher.  This will start
      replication of tables that were added to the subscribed-to publications
      since the last invocation of <command>REFRESH PUBLICATION</command> or
      since <command>CREATE SUBSCRIPTION</command>.
     </para>

     <para>
      <replaceable>refresh_option</replaceable> specifies additional options for the
      refresh operation.  The supported options are:

      <variablelist>
       <varlistentry>
        <term><literal>copy_data</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the existing data in the publications that are
          being subscribed to should be copied once the replication starts.
          The default is <literal>true</literal>.  (Previously subscribed
          tables are not copied.)
         </para>
        </listitem>
       </varlistentry>
      </variablelist></para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>ENABLE</literal></term>
    <listitem>
     <para>
      Enables the previously disabled subscription, starting the logical
      replication worker at the end of transaction.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>DISABLE</literal></term>
    <listitem>
     <para>
      Disables the running subscription, stopping the logical replication
      worker at the end of transaction.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>SET ( <replaceable class="parameter">subscription_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )</literal></term>
    <listitem>
     <para>
      This clause alters parameters originally set by
      <xref linkend="sql-createsubscription"/>.  See there for more
      information.  The parameters that can be altered
      are <literal>slot_name</literal>,
      <literal>synchronous_commit</literal>,
      <literal>binary</literal>, and
      <literal>streaming</literal>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_owner</replaceable></term>
    <listitem>
     <para>
      The user name of the new owner of the subscription.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_name</replaceable></term>
    <listitem>
     <para>
      The new name for the subscription.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Change the publication subscribed by a subscription to
   <literal>insert_only</literal>:
<programlisting>
ALTER SUBSCRIPTION mysub SET PUBLICATION insert_only;
</programlisting>
  </para>

  <para>
   Disable (stop) the subscription:
<programlisting>
ALTER SUBSCRIPTION mysub DISABLE;
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   <command>ALTER 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-dropsubscription"/></member>
   <member><xref linkend="sql-createpublication"/></member>
   <member><xref linkend="sql-alterpublication"/></member>
  </simplelist>
 </refsect1>
</refentry>
