fix_block_by_drop_subscription_v1.patch

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 5de9999..f07143e 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -511,51 +511,67 @@ DropSubscription(DropSubscriptionStmt *stmt)
 	/* Protect against launcher restarting the worker. */
 	LWLockAcquire(LogicalRepLauncherLock, LW_EXCLUSIVE);
 
-	/* Kill the apply worker so that the slot becomes accessible. */
-	logicalrep_worker_stop(subid);
-
-	/* Remove the origin tracking if exists. */
-	snprintf(originname, sizeof(originname), "pg_%u", subid);
-	originid = replorigin_by_name(originname, true);
-	if (originid != InvalidRepOriginId)
-		replorigin_drop(originid);
-
-	/* If the user asked to not drop the slot, we are done mow.*/
-	if (!stmt->drop_slot)
-	{
-		heap_close(rel, NoLock);
-		return;
-	}
-
 	/*
-	 * Otherwise drop the replication slot at the publisher node using
-	 * the replication connection.
+	 * replorigin_drop can throw an exception. we must release
+	 * LogicalRepLauncherLock for the case.
 	 */
-	load_file("libpqwalreceiver", false);
+	PG_TRY();
+	{
+		/* Kill the apply worker so that the slot becomes accessible. */
+		logicalrep_worker_stop(subid);
 
-	initStringInfo(&cmd);
-	appendStringInfo(&cmd, "DROP_REPLICATION_SLOT \"%s\"", slotname);
+		/* Remove the origin tracking if exists. */
+		snprintf(originname, sizeof(originname), "pg_%u", subid);
+		originid = replorigin_by_name(originname, true);
+		if (originid != InvalidRepOriginId)
+			replorigin_drop(originid);
 
-	wrconn = walrcv_connect(conninfo, true, subname, &err);
-	if (wrconn == NULL)
-		ereport(ERROR,
-				(errmsg("could not connect to publisher when attempting to "
-						"drop the replication slot \"%s\"", slotname),
-				 errdetail("The error was: %s", err)));
+		/* If the user asked to not drop the slot, we are done now.*/
+		if (stmt->drop_slot)
+		{
+			/*
+			 * Otherwise drop the replication slot at the publisher node using
+			 * the replication connection.
+			 */
+			load_file("libpqwalreceiver", false);
+
+			initStringInfo(&cmd);
+			appendStringInfo(&cmd, "DROP_REPLICATION_SLOT \"%s\"", slotname);
+
+			wrconn = walrcv_connect(conninfo, true, subname, &err);
+			if (wrconn == NULL || !walrcv_command(wrconn, cmd.data, &err))
+			{
+				if (wrconn == NULL)
+					ereport(ERROR,
+							(errmsg("could not connect to publisher when "
+									"attempting to drop the "
+									"replication slot \"%s\"", slotname),
+							 errdetail("The error was: %s", err)));
 
-	if (!walrcv_command(wrconn, cmd.data, &err))
-		ereport(ERROR,
-				(errmsg("could not drop the replication slot \"%s\" on publisher",
-						slotname),
-				 errdetail("The error was: %s", err)));
-	else
-		ereport(NOTICE,
-				(errmsg("dropped replication slot \"%s\" on publisher",
-						slotname)));
+				ereport(ERROR,
+						(errmsg("could not drop the replication slot \"%s\" on publisher",
+								slotname),
+						 errdetail("The error was: %s", err)));
+			}
 
-	walrcv_disconnect(wrconn);
+			ereport(NOTICE,
+					(errmsg("dropped replication slot \"%s\" on publisher",
+							slotname)));
 
-	pfree(cmd.data);
+			pfree(cmd.data);
+		}
+	}
+	PG_CATCH();
+	{
+		LWLockRelease(LogicalRepLauncherLock);
+		PG_RE_THROW();
+	}
+	PG_END_TRY();
+
+	LWLockRelease(LogicalRepLauncherLock);
+
+	if (wrconn)
+		walrcv_disconnect(wrconn);
 
 	heap_close(rel, NoLock);
 }