v85_amit_1.patch.txt

diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml
index bfa2a13377..a9ff6acd31 100644
--- a/doc/src/sgml/logicaldecoding.sgml
+++ b/doc/src/sgml/logicaldecoding.sgml
@@ -365,19 +365,18 @@ postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NU
     <title>Replication Slot Synchronization</title>
     <para>
      The logical replication slots on the primary can be synchronized to
-     the hot standby by enabling <literal>failover</literal> during slot
-     creation (e.g., using the <literal>failover</literal> parameter of
+     the hot standby by using the <literal>failover</literal> parameter of
      <link linkend="pg-create-logical-replication-slot">
      <function>pg_create_logical_replication_slot</function></link>, or
      using the <link linkend="sql-createsubscription-params-with-failover">
      <literal>failover</literal></link> option of
-     <command>CREATE SUBSCRIPTION</command>), and then calling
+     <command>CREATE SUBSCRIPTION</command> during slot creation, and then calling
      <link linkend="pg-sync-replication-slots">
      <function>pg_sync_replication_slots</function></link>
      on the standby. For the synchronization to work, it is mandatory to
-     have a physical replication slot between the primary and the standby (e.g.,
+     have a physical replication slot between the primary and the standby aka
      <link linkend="guc-primary-slot-name"><varname>primary_slot_name</varname></link>
-     should be configured on the standby), and
+     should be configured on the standby, and
      <link linkend="guc-hot-standby-feedback"><varname>hot_standby_feedback</varname></link>
      must be enabled on the standby. It is also necessary to specify a valid
      <literal>dbname</literal> in the
diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c
index feb04e1451..eb238cef92 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -304,6 +304,12 @@ reserve_wal_for_local_slot(XLogRecPtr restart_lsn)
 		 * number. However, if no WAL segment files have been removed by a
 		 * checkpoint since startup, we need to search for the oldest segment
 		 * file from the current timeline existing in XLOGDIR.
+		 *
+		 * XXX: Currently, we are searching for the oldest segment in the
+		 * current timeline as there is less chance of the slot's restart_lsn
+		 * from being some prior timeline, and even if it happens, in the worst
+		 * case, we will wait to sync till the slot's restart_lsn moved to the
+		 * current timeline.
 		 */
 		oldest_segno = XLogGetLastRemovedSegno() + 1;
 
@@ -685,11 +691,10 @@ synchronize_slots(WalReceiverConn *wrconn)
 }
 
 /*
- * Checks the primary server info.
+ * Checks the remote server info.
  *
- * Using the specified primary server connection, check whether we are a
- * cascading standby. It also validates primary_slot_name for non-cascading
- * standbys.
+ * We ensure that the 'primary_slot_name' exists on the remote server and
+ * the remote server is not a standby node.
  */
 static void
 check_primary_info(WalReceiverConn *wrconn, int elevel)