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13th chunk of `doc/src/sgml/ref/alter_table.sgml`
68827fdfec90621196c67288b4d7e9c6234ebf27c1ff58550000000100000fa9
 replicate the propagated data; so the
      trigger should not fire a second time on the replica, because that would
      lead to duplication.  However, if a trigger is used for another purpose
      such as creating external alerts, then it might be appropriate to set it
      to <literal>ENABLE ALWAYS</literal> so that it is also fired on
      replicas.
     </para>

     <para>
      When this command is applied to a partitioned table, the states of
      corresponding clone triggers in the partitions are updated too,
      unless <literal>ONLY</literal> is specified.
     </para>

     <para>
      This command acquires a <literal>SHARE ROW EXCLUSIVE</literal> lock.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altertable-desc-disable-enable-rule">
    <term><literal>DISABLE</literal>/<literal>ENABLE [ REPLICA | ALWAYS ] RULE</literal></term>
    <listitem>
     <para>
      These forms configure the firing of rewrite rules belonging to the table.
      A disabled rule is still known to the system, but is not applied
      during query rewriting. The semantics are as for disabled/enabled
      triggers. This configuration is ignored for <literal>ON SELECT</literal> rules, which
      are always applied in order to keep views working even if the current
      session is in a non-default replication role.
     </para>

     <para>
      The rule firing mechanism is also affected by the configuration variable
      <xref linkend="guc-session-replication-role"/>, analogous to triggers as
      described above.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altertable-desc-disable-enable-row-level-security">
    <term><literal>DISABLE</literal>/<literal>ENABLE ROW LEVEL SECURITY</literal></term>
    <listitem>
     <para>
      These forms control the application of row security policies belonging
      to the table.  If enabled and no policies exist for the table, then a
      default-deny policy is applied.  Note that policies can exist for a table
      even if row-level security is disabled.  In this case, the policies will
      <emphasis>not</emphasis> be applied and the policies will be ignored.
      See also
      <link linkend="sql-createpolicy"><command>CREATE POLICY</command></link>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altertable-desc-force-row-level-security">
    <term><literal>NO FORCE</literal>/<literal>FORCE ROW LEVEL SECURITY</literal></term>
    <listitem>
     <para>
      These forms control the application of row security policies belonging
      to the table when the user is the table owner.  If enabled, row-level
      security policies will be applied when the user is the table owner.  If
      disabled (the default) then row-level security will not be applied when
      the user is the table owner.
      See also
      <link linkend="sql-createpolicy"><command>CREATE POLICY</command></link>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altertable-desc-cluster-on">
    <term><literal>CLUSTER ON</literal></term>
    <listitem>
     <para>
      This form selects the default index for future
      <link linkend="sql-cluster"><command>CLUSTER</command></link>
      operations.  It does not actually re-cluster the table.
     </para>
     <para>
      Changing cluster options acquires a <literal>SHARE UPDATE EXCLUSIVE</literal> lock.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-altertable-desc-set-without-cluster">
    <term><literal>SET WITHOUT CLUSTER</literal></term>
    <listitem>
     <para>
      This form removes the most recently used
      <link linkend="sql-cluster"><command>CLUSTER</command></link>
      index specification from the table.  This affects
      future cluster operations that don't specify an index.
     </para>
     <para>
      Changing cluster options acquires a <literal>SHARE UPDATE EXCLUSIVE</literal> lock.
     </para>
    </listitem>
Title: ALTER TABLE: Rule Management (Enable/Disable), Row-Level Security (Enable/Disable/Force), and Clustering
Summary
This section covers ALTER TABLE's rule management features, including enabling and disabling rewrite rules, similar to triggers, and explains how replication roles affect rule firing. It also details row-level security controls, such as enabling or disabling row-level security policies and forcing row-level security for table owners. Finally, it describes how to set or remove the default index for future CLUSTER operations.