From 34cd7afbeafb90da3c65a71cf12362c980019061 Mon Sep 17 00:00:00 2001
From: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Date: Tue, 9 Jul 2024 08:01:43 +0000
Subject: [PATCH v19 3/3] Notify users to roll back prepared transactions

---
 doc/src/sgml/ref/alter_subscription.sgml | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/ref/alter_subscription.sgml b/doc/src/sgml/ref/alter_subscription.sgml
index df44415661..58db97f415 100644
--- a/doc/src/sgml/ref/alter_subscription.sgml
+++ b/doc/src/sgml/ref/alter_subscription.sgml
@@ -233,8 +233,6 @@ ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> RENAME TO <
       <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>.
       Only a superuser can set <literal>password_required = false</literal>.
-      The <literal>two_phase</literal> parameter can only be altered when the
-      subscription is disabled.
      </para>
 
      <para>
@@ -256,6 +254,20 @@ ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> RENAME TO <
       <link linkend="sql-createsubscription-params-with-failover"><literal>failover</literal></link>
       option is enabled.
      </para>
+
+     <para>
+      The <link linkend="sql-createsubscription-params-with-two-phase"><literal>two_phase</literal></link>
+      parameter can only be altered when the subscription is disabled.
+      When altering the parameter from <literal>true</literal>
+      to <literal>false</literal>, the backend process checks for any incomplete
+      prepared transactions done by the logical replication worker (from when
+      <literal>two_phase</literal> parameter was still <literal>true</literal>)
+      and, if any are found, an error is reported. If this happens, you can
+      resolve prepared transactions on the publisher node or
+      manually roll back them on the subscriber, then try again. After the altering from
+      <literal>true</literal> to <literal>false</literal>, the publisher will
+      replicate transactions again when they are committed.
+     </para>
     </listitem>
    </varlistentry>
 
-- 
2.43.0