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[PATCH v51 08/10] Introduce an option to make logical replication database specific.
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* [PATCH v51 08/10] Introduce an option to make logical replication database specific.
@ 2026-04-03 10:34  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 365+ messages in thread

From: Antonin Houska @ 2026-04-03 10:34 UTC (permalink / raw)

By default, the logical decoding assumes access to shared catalogs, so the
snapshot builder needs to consider cluster-wide XIDs during startup. That in
turn means that, if any transaction is already running (and has XID assigned),
the snapshot builder needs to wait for its completion, as it does not know if
that transaction performed catalog changes earlier.

Possible problem with this concept is that if REPACK (CONCURRENTLY) is running
in some database, backends running the same command in other databases get
stuck until the first one has committed. Thus only as single backend in the
cluster can run REPACK (CONCURRENTLY) at any time. Likewise, REPACK
(CONCURRENTLY) can block walsenders starting on behalf of subscriptions
throughout the cluster.

This patch introduces the possibility for a backend to declare that its output
plugin does not use shared catalogs (i.e. catalogs that can be changed by
transactions running in other databases in the cluster). In that case, no
snapshot the backend will use during the decoding needs to contain information
about transactions running in other databases. Thus the snapshot builder only
needs to wait for completion of transactions in the current database.

Currently we only use this option in the REPACK background worker. It could
possibly be used in walsender involved in logical replication too, however
that would need thorough analysis of its output plugin.

The patch bumps WAL version number, due to a new field in xl_running_xacts.
---
 contrib/pg_visibility/pg_visibility.c       |  4 ++--
 src/backend/access/index/genam.c            | 18 ++++++++++++++++
 src/backend/access/rmgrdesc/standbydesc.c   |  2 ++
 src/backend/access/transam/xlog.c           |  2 +-
 src/backend/access/transam/xlogfuncs.c      |  2 +-
 src/backend/commands/repack_worker.c        |  8 +++++++
 src/backend/postmaster/bgwriter.c           |  2 +-
 src/backend/replication/logical/snapbuild.c | 10 ++++++++-
 src/backend/replication/slot.c              | 12 +++++++++--
 src/backend/storage/ipc/procarray.c         | 23 ++++++++++++++++++++-
 src/backend/storage/ipc/standby.c           | 14 +++++++++++--
 src/include/access/genam.h                  |  8 +++++++
 src/include/access/xlog_internal.h          |  2 +-
 src/include/storage/procarray.h             |  2 +-
 src/include/storage/standby.h               |  3 ++-
 src/include/storage/standbydefs.h           |  1 +
 16 files changed, 99 insertions(+), 14 deletions(-)

diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c
index dfab0b64cf5..d564bd2a00c 100644
--- a/contrib/pg_visibility/pg_visibility.c
+++ b/contrib/pg_visibility/pg_visibility.c
@@ -621,7 +621,7 @@ GetStrictOldestNonRemovableTransactionId(Relation rel)
 	else if (rel == NULL || rel->rd_rel->relisshared)
 	{
 		/* Shared relation: take into account all running xids */
-		runningTransactions = GetRunningTransactionData();
+		runningTransactions = GetRunningTransactionData(InvalidOid);
 		LWLockRelease(ProcArrayLock);
 		LWLockRelease(XidGenLock);
 		return runningTransactions->oldestRunningXid;
@@ -632,7 +632,7 @@ GetStrictOldestNonRemovableTransactionId(Relation rel)
 		 * Normal relation: take into account xids running within the current
 		 * database
 		 */
-		runningTransactions = GetRunningTransactionData();
+		runningTransactions = GetRunningTransactionData(InvalidOid);
 		LWLockRelease(ProcArrayLock);
 		LWLockRelease(XidGenLock);
 		return runningTransactions->oldestDatabaseRunningXid;
diff --git a/src/backend/access/index/genam.c b/src/backend/access/index/genam.c
index 1408989c568..df092dc999a 100644
--- a/src/backend/access/index/genam.c
+++ b/src/backend/access/index/genam.c
@@ -37,6 +37,14 @@
 #include "utils/ruleutils.h"
 #include "utils/snapmgr.h"
 
+/*
+ * If a backend is going to do logical decoding and if the output plugin does
+ * not need to access shared catalogs, setting this variable to false can make
+ * the decoding startup faster. In particular, the backend will not need to
+ * wait for completion of already running transactions in other databases.
+ */
+bool		accessSharedCatalogsInDecoding = true;
+
 
 /* ----------------------------------------------------------------
  *		general access method routines
@@ -394,6 +402,16 @@ systable_beginscan(Relation heapRelation,
 	SysScanDesc sysscan;
 	Relation	irel;
 
+	/*
+	 * If this backend promised that it won't access shared catalogs during
+	 * logical decoding, this seems to be the right place to check.
+	 *
+	 * XXX Should this be ereport(ERROR) ?
+	 */
+	Assert(!HistoricSnapshotActive() ||
+		   accessSharedCatalogsInDecoding ||
+		   !heapRelation->rd_rel->relisshared);
+
 	if (indexOK &&
 		!IgnoreSystemIndexes &&
 		!ReindexIsProcessingIndex(indexId))
diff --git a/src/backend/access/rmgrdesc/standbydesc.c b/src/backend/access/rmgrdesc/standbydesc.c
index 0a291354ae2..685d1bdb024 100644
--- a/src/backend/access/rmgrdesc/standbydesc.c
+++ b/src/backend/access/rmgrdesc/standbydesc.c
@@ -41,6 +41,8 @@ standby_desc_running_xacts(StringInfo buf, xl_running_xacts *xlrec)
 		for (i = 0; i < xlrec->subxcnt; i++)
 			appendStringInfo(buf, " %u", xlrec->xids[xlrec->xcnt + i]);
 	}
+
+	appendStringInfo(buf, "; dbid: %u", xlrec->dbid);
 }
 
 void
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2c1c6f88b74..8da8eff93e4 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7336,7 +7336,7 @@ CreateCheckPoint(int flags)
 	 * recovery we don't need to write running xact data.
 	 */
 	if (!shutdown && XLogStandbyInfoActive())
-		LogStandbySnapshot();
+		LogStandbySnapshot(InvalidOid);
 
 	START_CRIT_SECTION();
 
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 65bbaeda59c..0f5979691e6 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -245,7 +245,7 @@ pg_log_standby_snapshot(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("pg_log_standby_snapshot() can only be used if \"wal_level\" >= \"replica\"")));
 
-	recptr = LogStandbySnapshot();
+	recptr = LogStandbySnapshot(InvalidOid);
 
 	/*
 	 * As a convenience, return the WAL location of the last inserted record
diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c
index c85166ba849..ff34e246469 100644
--- a/src/backend/commands/repack_worker.c
+++ b/src/backend/commands/repack_worker.c
@@ -16,6 +16,7 @@
  */
 #include "postgres.h"
 
+#include "access/genam.h"
 #include "access/table.h"
 #include "access/xlog_internal.h"
 #include "access/xlogutils.h"
@@ -237,6 +238,13 @@ repack_setup_logical_decoding(Oid relid)
 
 	EnsureLogicalDecodingEnabled();
 
+	/*
+	 * By declaring that our output plugin does not need shared catalogs, we
+	 * avoid waiting for completion of transactions running in other databases
+	 * than the one we're connected to.
+	 */
+	accessSharedCatalogsInDecoding = false;
+
 	/*
 	 * Neither prepare_write nor do_write callback nor update_progress is
 	 * useful for us.
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1d8947774a9..a30de4262eb 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -289,7 +289,7 @@ BackgroundWriterMain(const void *startup_data, size_t startup_data_len)
 			if (now >= timeout &&
 				last_snapshot_lsn <= GetLastImportantRecPtr())
 			{
-				last_snapshot_lsn = LogStandbySnapshot();
+				last_snapshot_lsn = LogStandbySnapshot(InvalidOid);
 				last_snapshot_ts = now;
 			}
 		}
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index b4269a3b102..2e3926e1d13 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -125,6 +125,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "access/genam.h"
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
@@ -1465,7 +1466,14 @@ SnapBuildWaitSnapshot(xl_running_xacts *running, TransactionId cutoff)
 	 */
 	if (!RecoveryInProgress())
 	{
-		LogStandbySnapshot();
+		Oid			dbid;
+
+		/*
+		 * Only consider transactions of the current database if our plugin is
+		 * not supposed to access shared catalogs.
+		 */
+		dbid = accessSharedCatalogsInDecoding ? InvalidOid : MyDatabaseId;
+		LogStandbySnapshot(dbid);
 	}
 }
 
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index a9092fc2382..d553bd5dbff 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -39,6 +39,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "access/genam.h"
 #include "access/transam.h"
 #include "access/xlog_internal.h"
 #include "access/xlogrecovery.h"
@@ -1760,9 +1761,16 @@ ReplicationSlotReserveWal(void)
 	if (!RecoveryInProgress() && SlotIsLogical(slot))
 	{
 		XLogRecPtr	flushptr;
+		Oid			dbid;
 
-		/* make sure we have enough information to start */
-		flushptr = LogStandbySnapshot();
+		/*
+		 * Make sure we have enough information to start.
+		 *
+		 * Only consider transactions of the current database if our plugin is
+		 * not supposed to access shared catalogs.
+		 */
+		dbid = accessSharedCatalogsInDecoding ? InvalidOid : MyDatabaseId;
+		flushptr = LogStandbySnapshot(dbid);
 
 		/* and make sure it's fsynced to disk */
 		XLogFlush(flushptr);
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index cc207cb56e3..92ed34128e5 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -2631,9 +2631,11 @@ ProcArrayInstallRestoredXmin(TransactionId xmin, PGPROC *proc)
  *
  * Note that if any transaction has overflowed its cached subtransactions
  * then there is no real need include any subtransactions.
+ *
+ * If 'dbid' is valid, only gather transactions running in that database.
  */
 RunningTransactions
-GetRunningTransactionData(void)
+GetRunningTransactionData(Oid dbid)
 {
 	/* result workspace */
 	static RunningTransactionsData CurrentRunningXactsData;
@@ -2708,6 +2710,18 @@ GetRunningTransactionData(void)
 		if (!TransactionIdIsValid(xid))
 			continue;
 
+		/*
+		 * Filter by database OID if requested.
+		 */
+		if (OidIsValid(dbid))
+		{
+			int			pgprocno = arrayP->pgprocnos[index];
+			PGPROC	   *proc = &allProcs[pgprocno];
+
+			if (proc->databaseId != dbid)
+				continue;
+		}
+
 		/*
 		 * Be careful not to exclude any xids before calculating the values of
 		 * oldestRunningXid and suboverflowed, since these are used to clean
@@ -2758,6 +2772,12 @@ GetRunningTransactionData(void)
 			PGPROC	   *proc = &allProcs[pgprocno];
 			int			nsubxids;
 
+			/*
+			 * Filter by database OID if requested.
+			 */
+			if (OidIsValid(dbid) && proc->databaseId != dbid)
+				continue;
+
 			/*
 			 * Save subtransaction XIDs. Other backends can't add or remove
 			 * entries while we're holding XidGenLock.
@@ -2791,6 +2811,7 @@ GetRunningTransactionData(void)
 	 * increases if slots do.
 	 */
 
+	CurrentRunningXacts->dbid = dbid;
 	CurrentRunningXacts->xcnt = count - subcount;
 	CurrentRunningXacts->subxcnt = subcount;
 	CurrentRunningXacts->subxid_status = suboverflowed ? SUBXIDS_IN_SUBTRANS : SUBXIDS_IN_ARRAY;
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index de9092fdf5b..c653ea742bc 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -1188,6 +1188,14 @@ standby_redo(XLogReaderState *record)
 		xl_running_xacts *xlrec = (xl_running_xacts *) XLogRecGetData(record);
 		RunningTransactionsData running;
 
+		/*
+		 * Records issued for specific database are not suitable for physical
+		 * replication because that affects the whole cluster. In particular,
+		 * the list of XID is probably incomplete here.
+		 */
+		if (OidIsValid(xlrec->dbid))
+			return;
+
 		running.xcnt = xlrec->xcnt;
 		running.subxcnt = xlrec->subxcnt;
 		running.subxid_status = xlrec->subxid_overflow ? SUBXIDS_MISSING : SUBXIDS_IN_ARRAY;
@@ -1277,11 +1285,12 @@ standby_redo(XLogReaderState *record)
  * as there's no independent knob to just enable logical decoding. For
  * details of how this is used, check snapbuild.c's introductory comment.
  *
+ * If 'dbid' is valid, only gather transactions running in that database.
  *
  * Returns the RecPtr of the last inserted record.
  */
 XLogRecPtr
-LogStandbySnapshot(void)
+LogStandbySnapshot(Oid dbid)
 {
 	XLogRecPtr	recptr;
 	RunningTransactions running;
@@ -1314,7 +1323,7 @@ LogStandbySnapshot(void)
 	 * Log details of all in-progress transactions. This should be the last
 	 * record we write, because standby will open up when it sees this.
 	 */
-	running = GetRunningTransactionData();
+	running = GetRunningTransactionData(dbid);
 
 	/*
 	 * GetRunningTransactionData() acquired ProcArrayLock, we must release it.
@@ -1358,6 +1367,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts)
 	xl_running_xacts xlrec;
 	XLogRecPtr	recptr;
 
+	xlrec.dbid = CurrRunningXacts->dbid;
 	xlrec.xcnt = CurrRunningXacts->xcnt;
 	xlrec.subxcnt = CurrRunningXacts->subxcnt;
 	xlrec.subxid_overflow = (CurrRunningXacts->subxid_status != SUBXIDS_IN_ARRAY);
diff --git a/src/include/access/genam.h b/src/include/access/genam.h
index b69320a7fc8..56c573399ab 100644
--- a/src/include/access/genam.h
+++ b/src/include/access/genam.h
@@ -136,6 +136,14 @@ typedef struct IndexOrderByDistance
 	bool		isnull;
 } IndexOrderByDistance;
 
+/*
+ * Is the backend interested in shared catalogs when performing logical
+ * decoding?
+ *
+ * XXX Is there a better place for this declaration?
+ */
+extern bool accessSharedCatalogsInDecoding;
+
 /*
  * generalized index_ interface routines (in indexam.c)
  */
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index 755835d63bf..ae19982d88d 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -31,7 +31,7 @@
 /*
  * Each page of XLOG file has a header like this:
  */
-#define XLOG_PAGE_MAGIC 0xD11E	/* can be used as WAL version indicator */
+#define XLOG_PAGE_MAGIC 0xD11F	/* can be used as WAL version indicator */
 
 typedef struct XLogPageHeaderData
 {
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index abdf021e66e..377b3060b9f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -49,7 +49,7 @@ extern bool ProcArrayInstallImportedXmin(TransactionId xmin,
 										 VirtualTransactionId *sourcevxid);
 extern bool ProcArrayInstallRestoredXmin(TransactionId xmin, PGPROC *proc);
 
-extern RunningTransactions GetRunningTransactionData(void);
+extern RunningTransactions GetRunningTransactionData(Oid dbid);
 
 extern bool TransactionIdIsInProgress(TransactionId xid);
 extern TransactionId GetOldestNonRemovableTransactionId(Relation rel);
diff --git a/src/include/storage/standby.h b/src/include/storage/standby.h
index 6a314c693cd..8715c08e94f 100644
--- a/src/include/storage/standby.h
+++ b/src/include/storage/standby.h
@@ -126,6 +126,7 @@ typedef enum
 
 typedef struct RunningTransactionsData
 {
+	Oid			dbid;			/* only track xacts in this database */
 	int			xcnt;			/* # of xact ids in xids[] */
 	int			subxcnt;		/* # of subxact ids in xids[] */
 	subxids_array_status subxid_status;
@@ -143,7 +144,7 @@ typedef RunningTransactionsData *RunningTransactions;
 extern void LogAccessExclusiveLock(Oid dbOid, Oid relOid);
 extern void LogAccessExclusiveLockPrepare(void);
 
-extern XLogRecPtr LogStandbySnapshot(void);
+extern XLogRecPtr LogStandbySnapshot(Oid dbid);
 extern void LogStandbyInvalidations(int nmsgs, SharedInvalidationMessage *msgs,
 									bool relcacheInitFileInval);
 
diff --git a/src/include/storage/standbydefs.h b/src/include/storage/standbydefs.h
index 231d251fd51..e75b7078766 100644
--- a/src/include/storage/standbydefs.h
+++ b/src/include/storage/standbydefs.h
@@ -46,6 +46,7 @@ typedef struct xl_standby_locks
  */
 typedef struct xl_running_xacts
 {
+	Oid			dbid;			/* only track xacts in this database */
 	int			xcnt;			/* # of xact ids in xids[] */
 	int			subxcnt;		/* # of subxact ids in xids[] */
 	bool		subxid_overflow;	/* snapshot overflowed, subxids missing */
-- 
2.47.3


--r2slln3zpmilwu22
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
	filename="v51-0009-Reserve-replication-slots-specifically-for-REPAC.patch"



^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v1] Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 11:07  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 12:08  Bertrand Drouvot <[email protected]>
  0 siblings, 1 reply; 365+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 12:08 UTC (permalink / raw)
  To: [email protected]

Hi hackers,

while playing with the new ALTER SUBSCRIPTION parameter added in a5918fddf10,
I realized that the subscription is not re-read once we acquire the lock in
AlterSubscription().

This pre-existing issue is now more visible after a5918fddf10:

1/ two concurrent ALTER SUBSCRIPTION SET (conflict_log_destination = 'table')
could result in the second session attempting to create an already-existing
conflict log table, producing a confusing "relation already exists" error:

ERROR:  relation "pg_conflict_log_24614" already exists

It's confusing because ALTER SUBSCRIPTION SET (conflict_log_destination = 'table')
would not report an error if the conflict table already exists (and no concurrent
ALTER is running).

2/ a concurrent DROP followed by the ALTER would emit a NOTICE about creating the
conflict log table before failing with "referenced subscription was concurrently
dropped". That sounds like a weird messaging:

NOTICE:  created conflict log table "pg_conflict.pg_conflict_log_24620" for subscription "mysub"
ERROR:  referenced subscription was concurrently dropped

The attached fixes it 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.

3/ the "privileges" checks are still also done before the lock acquisition because
we don't want to lock an object we don't have privileges on.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com


^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* Re: Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 12:27  Dilip Kumar <[email protected]>
  parent: Bertrand Drouvot <[email protected]>
  0 siblings, 1 reply; 365+ messages in thread

From: Dilip Kumar @ 2026-07-02 12:27 UTC (permalink / raw)
  To: Bertrand Drouvot <[email protected]>; +Cc: [email protected]

On Thu, Jul 2, 2026 at 5:38 PM Bertrand Drouvot
<[email protected]> wrote:
>
> Hi hackers,
>
> while playing with the new ALTER SUBSCRIPTION parameter added in a5918fddf10,
> I realized that the subscription is not re-read once we acquire the lock in
> AlterSubscription().
>
> This pre-existing issue is now more visible after a5918fddf10:
>
> 1/ two concurrent ALTER SUBSCRIPTION SET (conflict_log_destination = 'table')
> could result in the second session attempting to create an already-existing
> conflict log table, producing a confusing "relation already exists" error:
>
> ERROR:  relation "pg_conflict_log_24614" already exists
>
> It's confusing because ALTER SUBSCRIPTION SET (conflict_log_destination = 'table')
> would not report an error if the conflict table already exists (and no concurrent
> ALTER is running).
>
> 2/ a concurrent DROP followed by the ALTER would emit a NOTICE about creating the
> conflict log table before failing with "referenced subscription was concurrently
> dropped". That sounds like a weird messaging:
>
> NOTICE:  created conflict log table "pg_conflict.pg_conflict_log_24620" for subscription "mysub"
> ERROR:  referenced subscription was concurrently dropped
>
> The attached fixes it 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.
>
> 3/ the "privileges" checks are still also done before the lock acquisition because
> we don't want to lock an object we don't have privileges on.
>

Thanks Bertrand, yeah this seems like a valid issue, and I agree we
need to reread the subscription after acquiring the object lock.

-- 
Regards,
Dilip Kumar
Google





^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* RE: Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 12:48  Hayato Kuroda (Fujitsu) <[email protected]>
  parent: Dilip Kumar <[email protected]>
  0 siblings, 1 reply; 365+ messages in thread

From: Hayato Kuroda (Fujitsu) @ 2026-07-02 12:48 UTC (permalink / raw)
  To: Bertrand Drouvot <[email protected]>; +Cc: [email protected] <[email protected]>; 'Dilip Kumar' <[email protected]>

Dear Bertrand,

Good catch. Current code allows that old `sub` value is retained, so it sounds
reasonable fix even for me.

BTW, the issue that GetSubscription() is called before the LockSharedObject() looks
the existing issues even on REL_13_STABLE. So does it mean that there were no
cases that concurrent altering can be the unexpected state? At least,
"retain_dead_tuples" can avoid the issue because the launcher manages the
conflict slot.

Best regards,
Hayato Kuroda
FUJITSU LIMITED



^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* Re: Re-read subscription state after lock in AlterSubscription
@ 2026-07-02 13:20  Bertrand Drouvot <[email protected]>
  parent: Hayato Kuroda (Fujitsu) <[email protected]>
  0 siblings, 1 reply; 365+ messages in thread

From: Bertrand Drouvot @ 2026-07-02 13:20 UTC (permalink / raw)
  To: Hayato Kuroda (Fujitsu) <[email protected]>; +Cc: [email protected] <[email protected]>; 'Dilip Kumar' <[email protected]>

Hi Kuroda-san,

On Thu, Jul 02, 2026 at 12:48:53PM +0000, Hayato Kuroda (Fujitsu) wrote:
> Dear Bertrand,
> 
> Good catch. Current code allows that old `sub` value is retained, so it sounds
> reasonable fix even for me.
> 
> BTW, the issue that GetSubscription() is called before the LockSharedObject() looks
> the existing issues even on REL_13_STABLE. So does it mean that there were no
> cases that concurrent altering can be the unexpected state?

Yeah, but I think they would produce "tuple concurrently updated" error (due to 
CatalogTupleUpdate) so that invalid information could not be used.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com





^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* RE: Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 03:13  Hayato Kuroda (Fujitsu) <[email protected]>
  parent: Bertrand Drouvot <[email protected]>
  0 siblings, 1 reply; 365+ messages in thread

From: Hayato Kuroda (Fujitsu) @ 2026-07-03 03:13 UTC (permalink / raw)
  To: 'Bertrand Drouvot' <[email protected]>; +Cc: [email protected] <[email protected]>; 'Dilip Kumar' <[email protected]>

Dear Bertrand,

> Yeah, but I think they would produce "tuple concurrently updated" error (due to
> CatalogTupleUpdate) so that invalid information could not be used.

I confirmed with PG14 that tuple concurrently updated ERROR can be raised when
ALTER SUBSCRIPTION DISABLE happens concurrently:

```
postgres=# ALTER SUBSCRIPTION sub DISABLE ;
ERROR:  tuple concurrently updated
```

It might be harmless but I think the correct ERROR should be reported: the patch
should be backpatched. Thought?

Best regards,
Hayato Kuroda
FUJITSU LIMITED






^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* Re: Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 04:19  Bertrand Drouvot <[email protected]>
  parent: Hayato Kuroda (Fujitsu) <[email protected]>
  0 siblings, 1 reply; 365+ messages in thread

From: Bertrand Drouvot @ 2026-07-03 04:19 UTC (permalink / raw)
  To: Hayato Kuroda (Fujitsu) <[email protected]>; +Cc: [email protected] <[email protected]>; 'Dilip Kumar' <[email protected]>

Hi Kuroda-san,

On Fri, Jul 03, 2026 at 03:13:08AM +0000, Hayato Kuroda (Fujitsu) wrote:
> Dear Bertrand,
> 
> > Yeah, but I think they would produce "tuple concurrently updated" error (due to
> > CatalogTupleUpdate) so that invalid information could not be used.
> 
> I confirmed with PG14 that tuple concurrently updated ERROR can be raised when
> ALTER SUBSCRIPTION DISABLE happens concurrently:
> 
> ```
> postgres=# ALTER SUBSCRIPTION sub DISABLE ;
> ERROR:  tuple concurrently updated
> ```

Yeah, reproducible by using a breakpoint just before acquiring the lock for example.

> It might be harmless but I think the correct ERROR should be reported: the patch
> should be backpatched. Thought?

I'm not sure about the back patch part as it would only improve error messages
in a rare race condition (and there is no risk of invalid data being used).

Since a5918fddf10, that's a different story because a table creation is now
involved.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com





^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* Re: Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 04:50  Dilip Kumar <[email protected]>
  parent: Bertrand Drouvot <[email protected]>
  0 siblings, 1 reply; 365+ messages in thread

From: Dilip Kumar @ 2026-07-03 04:50 UTC (permalink / raw)
  To: Bertrand Drouvot <[email protected]>; +Cc: Hayato Kuroda (Fujitsu) <[email protected]>; [email protected] <[email protected]>

On Fri, Jul 3, 2026 at 9:49 AM Bertrand Drouvot
<[email protected]> wrote:
>
> Hi Kuroda-san,
>
> On Fri, Jul 03, 2026 at 03:13:08AM +0000, Hayato Kuroda (Fujitsu) wrote:
> > Dear Bertrand,
> >
> > > Yeah, but I think they would produce "tuple concurrently updated" error (due to
> > > CatalogTupleUpdate) so that invalid information could not be used.
> >
> > I confirmed with PG14 that tuple concurrently updated ERROR can be raised when
> > ALTER SUBSCRIPTION DISABLE happens concurrently:
> >
> > ```
> > postgres=# ALTER SUBSCRIPTION sub DISABLE ;
> > ERROR:  tuple concurrently updated
> > ```
>
> Yeah, reproducible by using a breakpoint just before acquiring the lock for example.
>
> > It might be harmless but I think the correct ERROR should be reported: the patch
> > should be backpatched. Thought?
>
> I'm not sure about the back patch part as it would only improve error messages
> in a rare race condition (and there is no risk of invalid data being used).

Patch LGTM. IMHO we can backpatch this as it is a small change and
also fixes the bug, without this fix a non-superuser executing  ALTER
SUBSCRIPTION could bypass the password_required=false restriction if a
concurrent transaction
updated that flag.  However, we could argue that this is a corner case
and can be skipped but given the patch's simplicity, I recommend
backpatching.

-- 
Regards,
Dilip Kumar
Google





^ permalink  raw  reply  [nested|flat] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 1/2] Re-read subscription state after lock in AlterSubscription
@ 2026-07-03 05:17  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Hayato Kuroda (Fujitsu) <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread

* [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
@ 2026-07-03 05:18  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 365+ 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 <[email protected]>
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] 365+ messages in thread