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[PATCH v1] Re-read subscription state after lock in AlterSubscription
334+ messages / 1 participants
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* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 11:07 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion:
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--MHKy70OBPdw7Q14M--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:17 UTC (permalink / raw)

AlterSubscription() reads the subscription's catalog state via GetSubscription()
before acquiring AccessExclusiveLock on the subscription object. A concurrent
session that commits a DROP or ALTER between the read and the lock acquisition
leaves the other session acting with stale information once it unblocks.

Fix by:

- Re-reading the subscription tuple after LockSharedObject() and refreshing the
  Subscription struct.
- Moving the local variable assignments to after the re-read.
- Re-checking the password_required privilege restriction after the re-read.

Remarks:

1/ not re-checking password_required after the re-read would still produce a
"tuple concurrently updated" error, but re-checking it allows us to display a
better error message.

2/ the ownership check is intentionally not re-done after the lock because
AlterSubscriptionOwner() does not take AccessExclusiveLock on the subscription
object: it only takes RowExclusiveLock on the pg_subscription catalog table.
This means ownership can change regardless of our lock, making a re-check after
lock acquisition pointless. The existing "tuple concurrently updated" error from
CatalogTupleUpdate() already provides a protection if ownership changes
concurrently.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 41 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 5 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 4292e7fb8f4..be03b3eb7e1 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1695,11 +1695,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	 */
 	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
 
-	retain_dead_tuples = sub->retaindeadtuples;
-	origin = sub->origin;
-	max_retention = sub->maxretention;
-	retention_active = sub->retentionactive;
-
 	/*
 	 * Don't allow non-superuser modification of a subscription with
 	 * password_required=false.
@@ -1713,6 +1708,42 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 	/* Lock the subscription so nobody else can do anything with it. */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	heap_freetuple(tup);
+	tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+							  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+
+	/* Refresh the subscription. */
+	pfree(sub);
+	sub = GetSubscription(subid, false, orig_conninfo_needed, false);
+
+	/*
+	 * Re-check whether a non-superuser is allowed to alter this subscription.
+	 * A concurrent ALTER may have set password_required=false while we were
+	 * waiting for the lock.
+	 */
+	if (!sub->passwordrequired && !superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("password_required=false is superuser-only"),
+				 errhint("Subscriptions with the password_required option set to false may only be created or modified by the superuser.")));
+
+	retain_dead_tuples = sub->retaindeadtuples;
+	origin = sub->origin;
+	max_retention = sub->maxretention;
+	retention_active = sub->retentionactive;
+
 	/* Form a new tuple. */
 	memset(values, 0, sizeof(values));
 	memset(nulls, false, sizeof(nulls));
-- 
2.34.1


--IX1d9TnmxjGKMYcM
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-Re-read-subscription-state-after-lock-in-DropSubs.patch"



^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--






^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--






^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--






^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--






^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--






^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--






^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--





^ permalink  raw  reply  [nested|flat] 334+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18 Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
  0 siblings, 0 replies; 334+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 05:18 UTC (permalink / raw)

Similarly to what has been done for AlterSubscription() in XXXX, re-read the
subscription tuple after LockSharedObject() in DropSubscription().

A concurrent DROP or ALTER may have committed while we were waiting for the lock.
Without a re-read, DropSubscription would deal with invalid data, which currently
produces a confusing "tuple concurrently updated" elog() from CatalogTupleDelete().

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Reviewed-by:
Discussion: https://postgr.es/m/akZUpiDa1UfmzYxL%40bdtpg
---
 src/backend/commands/subscriptioncmds.c | 36 ++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)
 100.0% src/backend/commands/

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index be03b3eb7e1..6db92a931b9 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -2582,17 +2582,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		return;
 	}
 
-	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
-							Anum_pg_subscription_subconninfo, &isnull);
-	if (!isnull)
-		subconninfo = TextDatumGetCString(datum);
-
 	form = (Form_pg_subscription) GETSTRUCT(tup);
 	subid = form->oid;
-	subowner = form->subowner;
-	subserver = form->subserver;
-	subconflictlogrelid = form->subconflictlogrelid;
-	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
 
 	/* must be owner */
 	if (!object_ownercheck(SubscriptionRelationId, subid, GetUserId()))
@@ -2608,6 +2599,33 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 */
 	LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock);
 
+	/*
+	 * Re-read the subscription tuple after acquiring the lock. A concurrent
+	 * DROP or ALTER may have committed before we acquired the lock.
+	 */
+	ReleaseSysCache(tup);
+	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
+						  CStringGetDatum(stmt->subname));
+
+	if (!HeapTupleIsValid(tup))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("subscription \"%s\" does not exist",
+						stmt->subname)));
+
+	form = (Form_pg_subscription) GETSTRUCT(tup);
+	subowner = form->subowner;
+	subserver = form->subserver;
+	subconflictlogrelid = form->subconflictlogrelid;
+	must_use_password = !superuser_arg(subowner) && form->subpasswordrequired;
+
+	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
+							Anum_pg_subscription_subconninfo, &isnull);
+	if (!isnull)
+		subconninfo = TextDatumGetCString(datum);
+	else
+		subconninfo = NULL;
+
 	/* Get subname */
 	datum = SysCacheGetAttrNotNull(SUBSCRIPTIONOID, tup,
 								   Anum_pg_subscription_subname);
-- 
2.34.1


--IX1d9TnmxjGKMYcM--






^ permalink  raw  reply  [nested|flat] 334+ messages in thread