v2-0001-clean-up-for-776621a5.patch

From 9828953dc478a2dd4895f3482cb1aafb332b142c Mon Sep 17 00:00:00 2001
From: Hou Zhijie <houzj.fnst@cn.fujitsu.com>
Date: Wed, 31 Jan 2024 10:53:08 +0800
Subject: [PATCH v2] clean up for 776621a5

1. Improve the documentation in create_subscription.sgml.
2. Remove the spurious blank line in subscriptioncmds.c.
3. Remove the NOTICE section for alter_replication_slot in subscriptioncmds.c.
4. Optimize ReplicationSlotAlter() function to prevent disk flushing when the
   slot's data remains unchanged.
---
 doc/src/sgml/ref/create_subscription.sgml |  5 ++---
 doc/src/sgml/ref/pg_dump.sgml             |  4 +---
 src/backend/commands/subscriptioncmds.c   |  8 --------
 src/backend/replication/slot.c            | 14 +++++++++-----
 4 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/doc/src/sgml/ref/create_subscription.sgml b/doc/src/sgml/ref/create_subscription.sgml
index ee89ffb1d1..15794731bb 100644
--- a/doc/src/sgml/ref/create_subscription.sgml
+++ b/doc/src/sgml/ref/create_subscription.sgml
@@ -117,9 +117,8 @@ CREATE SUBSCRIPTION <replaceable class="parameter">subscription_name</replaceabl
           command should connect to the publisher at all.  The default
           is <literal>true</literal>.  Setting this to
           <literal>false</literal> will force the values of
-          <literal>create_slot</literal>, <literal>enabled</literal>,
-          <literal>copy_data</literal>, and <literal>failover</literal>
-          to <literal>false</literal>.
+          <literal>create_slot</literal>, <literal>enabled</literal> and
+          <literal>copy_data</literal> to <literal>false</literal>.
           (You cannot combine setting <literal>connect</literal>
           to <literal>false</literal> with
           setting <literal>create_slot</literal>, <literal>enabled</literal>,
diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml
index f8ae4220e1..0caf56e0e0 100644
--- a/doc/src/sgml/ref/pg_dump.sgml
+++ b/doc/src/sgml/ref/pg_dump.sgml
@@ -1591,9 +1591,7 @@ CREATE DATABASE foo WITH TEMPLATE template0;
    information might have to be changed.  If the subscription needs to
    be enabled for
    <link linkend="sql-createsubscription-params-with-failover"><literal>failover</literal></link>,
-   then same needs to be done by executing
-   <link linkend="sql-altersubscription-params-set">
-   <literal>ALTER SUBSCRIPTION ... SET (failover = true)</literal></link>
+   execute <link linkend="sql-altersubscription-params-set"><literal>ALTER SUBSCRIPTION ... SET (failover = true)</literal></link>
    after the slot has been created.  It might also be appropriate to
    truncate the target tables before initiating a new full table copy.  If users
    intend to copy initial data during refresh they must create the slot with
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index b647a81fc8..860f091eeb 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -73,7 +73,6 @@
 #define SUBOPT_LSN					0x00004000
 #define SUBOPT_ORIGIN				0x00008000
 
-
 /* check if the 'val' has 'bits' set */
 #define IsSet(val, bits)  (((val) & (bits)) == (bits))
 
@@ -852,9 +851,6 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
 					 (opts.failover || walrcv_server_version(wrconn) >= 170000))
 			{
 				walrcv_alter_slot(wrconn, opts.slot_name, opts.failover);
-				ereport(NOTICE,
-						(errmsg("changed the failover state of replication slot \"%s\" on publisher to %s",
-								opts.slot_name, opts.failover ? "true" : "false")));
 			}
 		}
 		PG_FINALLY();
@@ -1547,10 +1543,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 		PG_TRY();
 		{
 			walrcv_alter_slot(wrconn, sub->slotname, opts.failover);
-
-			ereport(NOTICE,
-					(errmsg("changed the failover state of replication slot \"%s\" on publisher to %s",
-							sub->slotname, opts.failover ? "true" : "false")));
 		}
 		PG_FINALLY();
 		{
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 110cb59783..fd4e96c9d6 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -696,12 +696,16 @@ ReplicationSlotAlter(const char *name, bool failover)
 				errmsg("cannot use %s with a physical replication slot",
 					   "ALTER_REPLICATION_SLOT"));
 
-	SpinLockAcquire(&MyReplicationSlot->mutex);
-	MyReplicationSlot->data.failover = failover;
-	SpinLockRelease(&MyReplicationSlot->mutex);
+	if (MyReplicationSlot->data.failover != failover)
+	{
+		SpinLockAcquire(&MyReplicationSlot->mutex);
+		MyReplicationSlot->data.failover = failover;
+		SpinLockRelease(&MyReplicationSlot->mutex);
+
+		ReplicationSlotMarkDirty();
+		ReplicationSlotSave();
+	}
 
-	ReplicationSlotMarkDirty();
-	ReplicationSlotSave();
 	ReplicationSlotRelease();
 }
 
-- 
2.30.0.windows.2