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help / color / mirror / Atom feedFrom: Bertrand Drouvot <[email protected]>
Subject: [PATCH v2 2/2] Re-read subscription state after lock in DropSubscription
Date: Fri, 3 Jul 2026 05:18:44 +0000
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--
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