v3_amit.1.patch.txt

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index bf7fbb79341..4c01d21b2f3 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -1802,7 +1802,13 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	List	   *rstates;
 	bool		must_use_password;
 
-	rel = table_open(SubscriptionRelationId, AccessShareLock);
+	/*
+	 * The launcher may concurrently start a new worker for this subscription.
+	 * During initialization, the worker checks for subscription validity and
+	 * exits if the subscription has already been dropped. See
+	 * InitializeLogRepWorker.
+	 */
+	rel = table_open(SubscriptionRelationId, RowExclusiveLock);
 
 	tup = SearchSysCache2(SUBSCRIPTIONNAME, ObjectIdGetDatum(MyDatabaseId),
 						  CStringGetDatum(stmt->subname));
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 4688becd34f..1c2c9889be7 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -5417,7 +5417,8 @@ InitializeLogRepWorker(void)
 
 	/*
 	 * Lock the subscription to prevent it from being concurrently dropped,
-	 * then re-verify its existence.
+	 * then re-verify its existence. After the initialization, the worker will
+	 * be terminated gracefully if the subscription is dropped.
 	 */
 	LockSharedObject(SubscriptionRelationId, MyLogicalRepWorker->subid, 0,
 					 AccessShareLock);
@@ -5432,18 +5433,9 @@ InitializeLogRepWorker(void)
 		if (am_leader_apply_worker())
 			ApplyLauncherForgetWorkerStartTime(MyLogicalRepWorker->subid);
 
-		/*
-		 * The shared object lock on subid is automatically released by
-		 * proc_exit(), so no explicit unlock is necessary here.
-		 */
-
 		proc_exit(0);
 	}
 
-	/*
-	 * The shared object lock on subid will be released at transaction end.
-	 */
-
 	MySubscriptionValid = true;
 	MemoryContextSwitchTo(oldctx);