Dropping publication breaks logical replication

From fa8d5b256e8d7ca1428695115aad115fbec6f11c Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Sat, 2 Aug 2025 18:46:49 +0530
Subject: [PATCH v1_PG13] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 ++++++-
 src/test/subscription/t/001_rep_changes.pl  | 48 ++++++++++++++++++++-
 2 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 3d98d60d6c4..b3bd2b92f58 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -642,6 +642,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -652,9 +657,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl
index c60ef1c4f52..8c33ae51f4b 100644
--- a/src/test/subscription/t/001_rep_changes.pl
+++ b/src/test/subscription/t/001_rep_changes.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 27;
+use Test::More tests => 28;
 
 # Initialize publisher node
 my $node_publisher = get_new_node('publisher');
@@ -390,6 +390,52 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*) FROM pg_replication_origin");
 is($result, qq(0), 'check replication origin was dropped on subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub1 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub1 CONNECTION '$publisher_connstr' PUBLICATION tap_pub1"
+);
+
+# Wait for initial table sync to finish
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub1');
+
+$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub1");
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub1/,
+	$offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub1 FOR TABLE tab_3");
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+$node_publisher->wait_for_catchup('tap_sub1');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab_3");
+is($result, qq(1),
+	'check that the incremental data is replicated after the publication is created'
+);
+
+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub1");
+
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
 
-- 
2.43.0

From 5d5e45a48ecbaf9dba05dd757a82ac98e35f0057 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 22:26:06 +0530
Subject: [PATCH v1_PG14] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c  | 16 +++++-
 src/test/subscription/t/021_alter_sub_pub.pl | 57 +++++++++++++++++++-
 2 files changed, 69 insertions(+), 4 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index a81215cff86..f463e4d6d60 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -841,6 +841,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -851,9 +856,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/021_alter_sub_pub.pl b/src/test/subscription/t/021_alter_sub_pub.pl
index 4c59d44e33f..9cc93caf7e9 100644
--- a/src/test/subscription/t/021_alter_sub_pub.pl
+++ b/src/test/subscription/t/021_alter_sub_pub.pl
@@ -1,12 +1,14 @@
 
 # Copyright (c) 2021, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 3;
+use Test::More tests => 4;
 
 # Initialize publisher node
 my $node_publisher = get_new_node('publisher');
@@ -81,6 +83,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub ADD PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From f0e05a438b89e86e6424c461aff6d2de618bd917 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 15:28:46 +0530
Subject: [PATCH v1_PG15] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 +++++-
 src/test/subscription/t/024_add_drop_pub.pl | 55 ++++++++++++++++++++-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 64f62de635f..9e427beed4f 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1773,6 +1773,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1783,9 +1788,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index eaf47e66f1a..b39feaf3119 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2022, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub SET PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH  PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 3d874dc02ccadb04723d4451da6da43bd1ed4d14 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 14:51:26 +0530
Subject: [PATCH v1_PG17] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 +++++-
 src/test/subscription/t/024_add_drop_pub.pl | 55 ++++++++++++++++++++-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 99518c6b6dd..fa0fb915f15 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1741,6 +1741,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1751,9 +1756,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index c0d7ffcb6b8..1ea7d4611da 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2024, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings FATAL => 'all';
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub SET PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH  PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 910b8d66e50050574cfb98a53d6a1ed8f00ac6ec Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 15:25:53 +0530
Subject: [PATCH v1_PG16] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 +++++-
 src/test/subscription/t/024_add_drop_pub.pl | 55 ++++++++++++++++++++-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 32b74bb4752..d83da138081 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1737,6 +1737,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1747,9 +1752,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index 8614b1b5b34..33ecfe7a415 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2023, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub SET PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH  PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 3d874dc02ccadb04723d4451da6da43bd1ed4d14 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 14:51:26 +0530
Subject: [PATCH v1_PG17] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 +++++-
 src/test/subscription/t/024_add_drop_pub.pl | 55 ++++++++++++++++++++-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 99518c6b6dd..fa0fb915f15 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1741,6 +1741,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1751,9 +1756,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index c0d7ffcb6b8..1ea7d4611da 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2024, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings FATAL => 'all';
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub SET PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH  PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From f0e05a438b89e86e6424c461aff6d2de618bd917 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 15:28:46 +0530
Subject: [PATCH v1_PG15] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 +++++-
 src/test/subscription/t/024_add_drop_pub.pl | 55 ++++++++++++++++++++-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 64f62de635f..9e427beed4f 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1773,6 +1773,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1783,9 +1788,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index eaf47e66f1a..b39feaf3119 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2022, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub SET PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH  PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 5d5e45a48ecbaf9dba05dd757a82ac98e35f0057 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 22:26:06 +0530
Subject: [PATCH v1_PG14] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c  | 16 +++++-
 src/test/subscription/t/021_alter_sub_pub.pl | 57 +++++++++++++++++++-
 2 files changed, 69 insertions(+), 4 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index a81215cff86..f463e4d6d60 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -841,6 +841,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -851,9 +856,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/021_alter_sub_pub.pl b/src/test/subscription/t/021_alter_sub_pub.pl
index 4c59d44e33f..9cc93caf7e9 100644
--- a/src/test/subscription/t/021_alter_sub_pub.pl
+++ b/src/test/subscription/t/021_alter_sub_pub.pl
@@ -1,12 +1,14 @@
 
 # Copyright (c) 2021, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 3;
+use Test::More tests => 4;
 
 # Initialize publisher node
 my $node_publisher = get_new_node('publisher');
@@ -81,6 +83,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub ADD PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 910b8d66e50050574cfb98a53d6a1ed8f00ac6ec Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 15:25:53 +0530
Subject: [PATCH v1_PG16] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 +++++-
 src/test/subscription/t/024_add_drop_pub.pl | 55 ++++++++++++++++++++-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 32b74bb4752..d83da138081 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1737,6 +1737,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1747,9 +1752,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index 8614b1b5b34..33ecfe7a415 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2023, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,57 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+my $oldpid = $node_publisher->safe_psql('postgres',
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+);
+
+# Set the subscription with a missing publication
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub SET PUBLICATION tap_pub_3");
+
+# Wait for the walsender to restart after altering the subscription
+$node_publisher->poll_query_until('postgres',
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub' AND state = 'streaming';"
+  )
+  or die
+  "Timed out while waiting for apply worker to restart after altering the subscription";
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres',"INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/, $offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub REFRESH  PUBLICATION");
+
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT * FROM tab_3");
+is($result, qq(1
+2), 'check that the incremental data is replicated after the publication is created');
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 29ff09285362319a6938d33d14d0e84a5a778608 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Sat, 2 Aug 2025 18:46:49 +0530
Subject: [PATCH v2_PG13] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 ++++++-
 src/test/subscription/t/001_rep_changes.pl  | 47 ++++++++++++++++++++-
 2 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 3d98d60d6c4..b3bd2b92f58 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -642,6 +642,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -652,9 +657,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl
index c60ef1c4f52..311c3e0cb45 100644
--- a/src/test/subscription/t/001_rep_changes.pl
+++ b/src/test/subscription/t/001_rep_changes.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 27;
+use Test::More tests => 28;
 
 # Initialize publisher node
 my $node_publisher = get_new_node('publisher');
@@ -390,6 +390,51 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*) FROM pg_replication_origin");
 is($result, qq(0), 'check replication origin was dropped on subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub1 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub1 CONNECTION '$publisher_connstr' PUBLICATION tap_pub1"
+);
+
+# Wait for initial table sync to finish
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub1');
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub1");
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub1/,
+	$offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub1 FOR TABLE tab_3");
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+$node_publisher->wait_for_catchup('tap_sub1');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab_3");
+is($result, qq(1),
+	'check that the incremental data is replicated after the publication is created'
+);
+
+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub1");
+
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
 
-- 
2.43.0

From c3ddf0daacc43a39653c627d2bf6d822efefc27e Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 15:28:46 +0530
Subject: [PATCH v3_PG15] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 ++++++-
 src/test/subscription/t/024_add_drop_pub.pl | 49 ++++++++++++++++++++-
 2 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 64f62de635f..9e427beed4f 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1773,6 +1773,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1783,9 +1788,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index eaf47e66f1a..2aa21c9cb0d 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2022, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,51 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub");
+
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub_3"
+);
+
+# Wait for initial table sync to finish
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub_3");
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/,
+	$offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab_3");
+is($result, qq(2),
+	'check that the incremental data is replicated after the publication is created'
+);
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 5a537d1cc1c474bbaccc948bc716c3fc809add34 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 14:51:26 +0530
Subject: [PATCH v3_PG17] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ...
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 ++++++-
 src/test/subscription/t/024_add_drop_pub.pl | 49 ++++++++++++++++++++-
 2 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 99518c6b6dd..fa0fb915f15 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1741,6 +1741,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1751,9 +1756,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index c0d7ffcb6b8..6694a3cf60d 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2024, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings FATAL => 'all';
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,51 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub");
+
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub_3"
+);
+
+# Wait for initial table sync to finish
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub_3");
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/,
+	$offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab_3");
+is($result, qq(2),
+	'check that the incremental data is replicated after the publication is created'
+);
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From d18abc404f80df221ca1e0a44f80847c43851d1f Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Sat, 2 Aug 2025 18:46:49 +0530
Subject: [PATCH v3_PG13] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 ++++++-
 src/test/subscription/t/001_rep_changes.pl  | 47 ++++++++++++++++++++-
 2 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 3d98d60d6c4..b3bd2b92f58 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -642,6 +642,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -652,9 +657,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl
index c60ef1c4f52..99f05897bbf 100644
--- a/src/test/subscription/t/001_rep_changes.pl
+++ b/src/test/subscription/t/001_rep_changes.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 27;
+use Test::More tests => 28;
 
 # Initialize publisher node
 my $node_publisher = get_new_node('publisher');
@@ -390,6 +390,51 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*) FROM pg_replication_origin");
 is($result, qq(0), 'check replication origin was dropped on subscriber');
 
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub1 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub1 CONNECTION '$publisher_connstr' PUBLICATION tap_pub1"
+);
+
+# Wait for initial table sync to finish
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub1');
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub1");
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub1/,
+	$offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub1 FOR TABLE tab_3");
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub1');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab_3");
+is($result, qq(2),
+	'check that the incremental data is replicated after the publication is created'
+);
+
+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub1");
+
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
 
-- 
2.43.0

From c0e734988024bcf6001d52259a197a3e2df385e4 Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 15:25:53 +0530
Subject: [PATCH v3_PG16] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ...
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c | 16 ++++++-
 src/test/subscription/t/024_add_drop_pub.pl | 49 ++++++++++++++++++++-
 2 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 32b74bb4752..d83da138081 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1737,6 +1737,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -1747,9 +1752,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/024_add_drop_pub.pl b/src/test/subscription/t/024_add_drop_pub.pl
index 8614b1b5b34..5266fe30172 100644
--- a/src/test/subscription/t/024_add_drop_pub.pl
+++ b/src/test/subscription/t/024_add_drop_pub.pl
@@ -1,7 +1,9 @@
 
 # Copyright (c) 2021-2023, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgreSQL::Test::Cluster;
@@ -80,6 +82,51 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub");
+
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub_3"
+);
+
+# Wait for initial table sync to finish
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub_3");
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/,
+	$offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab_3");
+is($result, qq(2),
+	'check that the incremental data is replicated after the publication is created'
+);
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0

From 5729539bde15f1810b01590610fa4b2b2f01c4db Mon Sep 17 00:00:00 2001
From: Vignesh C <vignesh21@gmail.com>
Date: Fri, 1 Aug 2025 22:26:06 +0530
Subject: [PATCH v3_PG14] Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... 
 command.

The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.
---
 src/backend/replication/pgoutput/pgoutput.c  | 16 +++++-
 src/test/subscription/t/021_alter_sub_pub.pl | 51 +++++++++++++++++++-
 2 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index a81215cff86..f463e4d6d60 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -841,6 +841,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
 
 /*
  * Load publications from the list of publication names.
+ *
+ * Here, we skip the publications that don't exist yet. This will allow us
+ * to silently continue the replication in the absence of a missing publication.
+ * This is required because we allow the users to create publications after they
+ * have specified the required publications at the time of replication start.
  */
 static List *
 LoadPublications(List *pubnames)
@@ -851,9 +856,16 @@ LoadPublications(List *pubnames)
 	foreach(lc, pubnames)
 	{
 		char	   *pubname = (char *) lfirst(lc);
-		Publication *pub = GetPublicationByName(pubname, false);
+		Publication *pub = GetPublicationByName(pubname, true);
 
-		result = lappend(result, pub);
+		if (pub)
+			result = lappend(result, pub);
+		else
+			ereport(WARNING,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("skipped loading publication: %s", pubname),
+					errdetail("The publication does not exist at this point in the WAL."),
+					errhint("Create the publication if it does not exist."));
 	}
 
 	return result;
diff --git a/src/test/subscription/t/021_alter_sub_pub.pl b/src/test/subscription/t/021_alter_sub_pub.pl
index 4c59d44e33f..c4d0b99a66a 100644
--- a/src/test/subscription/t/021_alter_sub_pub.pl
+++ b/src/test/subscription/t/021_alter_sub_pub.pl
@@ -1,12 +1,14 @@
 
 # Copyright (c) 2021, PostgreSQL Global Development Group
 
-# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION
+# This test checks behaviour of ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION and
+# ensures that creating a publication associated with a subscription at a later
+# point of time does not break logical replication.
 use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 3;
+use Test::More tests => 4;
 
 # Initialize publisher node
 my $node_publisher = get_new_node('publisher');
@@ -81,6 +83,51 @@ $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_1");
 is($result, qq(20|1|10), 'check initial data is copied to subscriber');
 
+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub");
+
+# Ensure that setting a missing publication to the subscription does not
+# disrupt existing logical replication. Instead, it should log a warning
+# while allowing replication to continue. Additionally, verify that replication
+# resumes after the missing publication is created for the publication table.
+
+# Create table on publisher and subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_3 (a int)");
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub_3"
+);
+
+# Wait for initial table sync to finish
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+my $offset = -s $node_publisher->logfile;
+
+$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub_3");
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(1)");
+
+# Verify that a warning is logged.
+$node_publisher->wait_for_log(
+	qr/WARNING: ( [A-Z0-9]+:)? skipped loading publication: tap_pub_3/,
+	$offset);
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_3 FOR TABLE tab_3");
+
+$node_publisher->safe_psql('postgres', "INSERT INTO tab_3 values(2)");
+
+$node_publisher->wait_for_catchup('tap_sub');
+
+# Verify that the insert operation gets replicated to subscriber after
+# publication is created.
+$result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab_3");
+is($result, qq(2),
+	'check that the incremental data is replicated after the publication is created'
+);
+
 # shutdown
 $node_subscriber->stop('fast');
 $node_publisher->stop('fast');
-- 
2.43.0