<!--
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> REFRESH SEQUENCES
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> SKIP ( <replaceable class="parameter">skip_option</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 rename a subscription or alter the owner, you must have
   <literal>CREATE</literal> permission on the database. In addition,
   to alter the owner, you must be able to <literal>SET ROLE</literal> to the
   new owning role. If the subscription has
   <literal>password_required=false</literal>, only superusers can modify it.
  </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>,
   <command>ALTER SUBSCRIPTION ... {SET|ADD|DROP} PUBLICATION ...</command>
   with <literal>refresh</literal> option as <literal>true</literal>,
   <command>ALTER SUBSCRIPTION ... SET (failover = true|false)</command> and
   <command>ALTER SUBSCRIPTION ... SET (two_phase = false)</command>
   cannot be executed inside a transaction block.
  </para>

  <para>
   Commands <command>ALTER SUBSCRIPTION ... REFRESH PUBLICATION</command> and
   <command>ALTER SUBSCRIPTION ... {SET|ADD|DROP} PUBLICATION ...</command>
   with <literal>refresh</literal> option as <literal>true</literal> also cannot
   be executed when the subscription has
   <link linkend="sql-createsubscription-params-with-two-phase"><literal>two_phase</literal></link>
   commit enabled, unless
   <link linkend="sql-createsubscription-params-with-copy-data"><literal>copy_data</literal></link>
   is <literal>false</literal>. See column <structfield>subtwophasestate</structfield>
   of <link linkend="catalog-pg-subscription"><structname>pg_subscription</structname></link>
   to know the actual two-phase state.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

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

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

   <varlistentry id="sql-altersubscription-params-setadddrop-publication">
    <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>
      These forms change 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.  We allow non-existent publications to be
      specified in <literal>ADD</literal> and <literal>SET</literal> variants
      so that users can add those later.  See <xref linkend="sql-createsubscription"/>
      for more information.  By default, this command will also act like
      <literal>REFRESH PUBLICATION</literal>.
     </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 <literal>false</literal>, the command will not try to refresh
          table and sequence information. <literal>REFRESH PUBLICATION</literal>
          should then be executed separately. The default is
          <literal>true</literal>.
         </para>
        </listitem>
       </varlistentry>
      </variablelist>

      Additionally, the options described under
      <literal>REFRESH PUBLICATION</literal> may be specified, to control the
      implicit refresh operation.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altersubscription-params-refresh-publication">
    <term><literal>REFRESH PUBLICATION</literal></term>
    <listitem>
     <para>
      Fetch missing table and sequence information from the publisher.  This will start
      replication of tables that were added to the subscribed-to publications
      since <link linkend="sql-createsubscription">
      <command>CREATE SUBSCRIPTION</command></link> or
      the last invocation of <command>REFRESH PUBLICATION</command>.
     </para>

     <para>
      The system catalog <link linkend="catalog-pg-subscription-rel">pg_subscription_rel</link>
      is updated to record all tables and sequences known to the subscription,
      that are still part of the publication.
     </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 to copy pre-existing data for tables and synchronize
          sequences in the publications that are being subscribed to when the replication
          starts. The default is <literal>true</literal>.
         </para>
         <para>
          Previously subscribed tables are not copied, even if a table's row
          filter <literal>WHERE</literal> clause has since been modified.
         </para>
         <para>
          Previously subscribed sequences are not re-synchronized. To do that,
          use <link linkend="sql-altersubscription-params-refresh-sequences">
          <command>ALTER SUBSCRIPTION ... REFRESH SEQUENCES</command></link>.
         </para>
         <para>
          See <xref linkend="sequence-definition-mismatches"/> for recommendations on how
          to handle any warnings about sequence definition differences between
          the publisher and the subscriber, which might occur when
          <literal>copy_data = true</literal>.
         </para>
         <para>
          See <xref linkend="sql-createsubscription-notes"/> for details of
          how <literal>copy_data = true</literal> can interact with the
          <link linkend="sql-createsubscription-params-with-origin"><literal>origin</literal></link>
          parameter.
         </para>
         <para>
          See the
          <link linkend="sql-createsubscription-params-with-binary"><literal>binary</literal></link>
          parameter of <command>CREATE SUBSCRIPTION</command> for details about
          copying pre-existing data in binary format.
         </para>
        </listitem>
       </varlistentry>
      </variablelist></para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altersubscription-params-refresh-sequences">
    <term><literal>REFRESH SEQUENCES</literal></term>
    <listitem>
     <para>
      Re-synchronize sequence data with the publisher. Unlike
      <link linkend="sql-altersubscription-params-refresh-publication">
      <command>ALTER SUBSCRIPTION ... REFRESH PUBLICATION</command></link> which
      only has the ability to synchronize newly added sequences,
      <literal>REFRESH SEQUENCES</literal> will re-synchronize the sequence
      data for all currently subscribed sequences. It does not add or remove
      sequences from the subscription to match the publication.
     </para>
     <para>
      See <xref linkend="sequence-definition-mismatches"/> for
      recommendations on how to handle any warnings about sequence definition
      differences between the publisher and the subscriber.
     </para>
     <para>
      See <xref linkend="sequences-out-of-sync"/> for recommendations on how to
      identify and handle out-of-sync sequences.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altersubscription-params-enable">
    <term><literal>ENABLE</literal></term>
    <listitem>
     <para>
      Enables a previously disabled subscription, starting the logical
      replication worker at the end of the transaction.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altersubscription-params-disable">
    <term><literal>DISABLE</literal></term>
    <listitem>
     <para>
      Disables a running subscription, stopping the logical replication
      worker at the end of the transaction.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altersubscription-params-set">
    <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
      <link linkend="sql-createsubscription-params-with-slot-name"><literal>slot_name</literal></link>,
      <link linkend="sql-createsubscription-params-with-synchronous-commit"><literal>synchronous_commit</literal></link>,
      <link linkend="sql-createsubscription-params-with-binary"><literal>binary</literal></link>,
      <link linkend="sql-createsubscription-params-with-streaming"><literal>streaming</literal></link>,
      <link linkend="sql-createsubscription-params-with-disable-on-error"><literal>disable_on_error</literal></link>,
      <link linkend="sql-createsubscription-params-with-password-required"><literal>password_required</literal></link>,
      <link linkend="sql-createsubscription-params-with-run-as-owner"><literal>run_as_owner</literal></link>,
      <link linkend="sql-createsubscription-params-with-origin"><literal>origin</literal></link>,
      <link linkend="sql-createsubscription-params-with-failover"><literal>failover</literal></link>,
      <link linkend="sql-createsubscription-params-with-two-phase"><literal>two_phase</literal></link>,
      <link linkend="sql-createsubscription-params-with-retain-dead-tuples"><literal>retain_dead_tuples</literal></link>, and
      <link linkend="sql-createsubscription-params-with-max-retention-duration"><literal>max_retention_duration</literal></link>.
      Only a superuser can set <literal>password_required = false</literal>.
     </para>

     <para>
      When altering the
      <link linkend="sql-createsubscription-params-with-slot-name"><literal>slot_name</literal></link>,
      the <literal>failover</literal> and <literal>two_phase</literal> property
      values of the named slot may differ from the counterpart
      <link linkend="sql-createsubscription-params-with-failover"><literal>failover</literal></link>
      and <link linkend="sql-createsubscription-params-with-two-phase"><literal>two_phase</literal></link>
      parameters specified in the subscription. When creating the slot, ensure
      the slot properties <literal>failover</literal> and <literal>two_phase</literal>
      match their counterpart parameters of the subscription.
      Otherwise, the slot on the publisher may behave differently from what these
      subscription options say: for example, the slot on the publisher could either be
      synced to the standbys even when the subscription's
      <link linkend="sql-createsubscription-params-with-failover"><literal>failover</literal></link>
      option is disabled or could be disabled for sync
      even when the subscription's
      <link linkend="sql-createsubscription-params-with-failover"><literal>failover</literal></link>
      option is enabled.
     </para>

     <para>
      The <link linkend="sql-createsubscription-params-with-failover"><literal>failover</literal></link>,
      <link linkend="sql-createsubscription-params-with-two-phase"><literal>two_phase</literal></link>, and
      <link linkend="sql-createsubscription-params-with-retain-dead-tuples"><literal>retain_dead_tuples</literal></link>
      parameters can only be altered when the subscription is disabled.
     </para>

     <para>
      When altering <link linkend="sql-createsubscription-params-with-two-phase"><literal>two_phase</literal></link>
      from <literal>true</literal> to <literal>false</literal>, the backend
      process reports an error if any prepared transactions done by the
      logical replication worker (from when <literal>two_phase</literal>
      parameter was still <literal>true</literal>) are found. You can resolve
      prepared transactions on the publisher node, or manually roll back them
      on the subscriber, and then try again. The transactions prepared by
      logical replication worker corresponding to a particular subscription have
      the following pattern: <quote><literal>pg_gid_%u_%u</literal></quote>
      (parameters: subscription <parameter>oid</parameter>, remote transaction id <parameter>xid</parameter>).
      To resolve such transactions manually, you need to roll back all
      the prepared transactions with corresponding subscription IDs in their
      names. Applications can check
      <link linkend="view-pg-prepared-xacts"><structname>pg_prepared_xacts</structname></link>
      to find the required prepared transactions. After the <literal>two_phase</literal>
      option is changed from <literal>true</literal> to <literal>false</literal>,
      the publisher will replicate the transactions again when they are committed.
     </para>

     <para>
      If the <link linkend="sql-createsubscription-params-with-retain-dead-tuples"><literal>retain_dead_tuples</literal></link>
      option is altered to <literal>false</literal> and no other subscription
      has this option enabled, the replication slot named
      <quote><literal>pg_conflict_detection</literal></quote>, created to retain
      dead tuples for conflict detection, will be dropped.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altersubscription-params-skip">
    <term><literal>SKIP ( <replaceable class="parameter">skip_option</replaceable> = <replaceable class="parameter">value</replaceable> )</literal></term>
    <listitem>
     <para>
      Skips applying all changes of the remote transaction.  If incoming data
      violates any constraints, logical replication will stop until it is
      resolved.  By using the <command>ALTER SUBSCRIPTION ... SKIP</command> command,
      the logical replication worker skips all data modification changes within
      the transaction.  This option has no effect on the transactions that are
      already prepared by enabling
      <link linkend="sql-createsubscription-params-with-two-phase"><literal>two_phase</literal></link>
      on the subscriber.
      After the logical replication worker successfully skips the transaction or
      finishes a transaction, the LSN (stored in
      <structname>pg_subscription</structname>.<structfield>subskiplsn</structfield>)
      is cleared.  See <xref linkend="logical-replication-conflicts"/> for
      the details of logical replication conflicts.
     </para>

     <para>
      <replaceable>skip_option</replaceable> specifies options for this operation.
      The supported option is:

      <variablelist>
       <varlistentry>
        <term><literal>lsn</literal> (<type>pg_lsn</type>)</term>
        <listitem>
         <para>
          Specifies the finish LSN of the remote transaction whose changes
          are to be skipped by the logical replication worker.  The finish LSN
          is the LSN at which the transaction is either committed or prepared.
          Skipping individual subtransactions is not supported.  Setting
          <literal>NONE</literal> resets the LSN.
         </para>
        </listitem>
       </varlistentry>
      </variablelist></para>
    </listitem>
   </varlistentry>

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

   <varlistentry id="sql-altersubscription-params-new-name">
    <term><replaceable class="parameter">new_name</replaceable></term>
    <listitem>
     <para>
      The new name for the subscription.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>

  <para>
   When specifying a parameter of type <type>boolean</type>, the
   <literal>=</literal> <replaceable class="parameter">value</replaceable>
   part can be omitted, which is equivalent to
   specifying <literal>TRUE</literal>.
  </para>
 </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>
