From 58b9cfaa5f806d527ad36904f8b3b67c05b70478 Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Fri, 3 Jul 2026 11:54:29 +0000 Subject: [PATCH v3 2/4] Re-read subscription state after lock in DropSubscription 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 Reviewed-by: Zhijie Hou Reviewed-by: Amit Kapila 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 517d46f47f9..e23b366a87d 100644 --- a/src/backend/commands/subscriptioncmds.c +++ b/src/backend/commands/subscriptioncmds.c @@ -2567,17 +2567,8 @@ 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())) @@ -2587,12 +2578,39 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel) /* DROP hook for the subscription being removed */ InvokeObjectDropHook(SubscriptionRelationId, subid, 0); + ReleaseSysCache(tup); + /* * Lock the subscription so nobody else can do anything with it (including * the replication workers). */ LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock); + /* + * Re-read the subscription tuple after acquiring the lock. A concurrent + * ALTER or DROP may have committed before we acquired the lock. + */ + tup = SearchSysCache1(SUBSCRIPTIONOID, ObjectIdGetDatum(subid)); + + 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