First commit to change APIs

src/backend/distributed/metadata/metadata_sync.c

@@ -663,12 +663,21 @@ DropMetadataSnapshotOnNode(WorkerNode *workerNode)
 	EnsureSequentialModeMetadataOperations();
 
 	char *userName = CurrentUserName();
+	List *dropMetadataCommandList = NIL;
 
 	/*
 	 * Detach partitions, break dependencies between sequences and table then
 	 * remove shell tables first.
 	 */
-	List *dropMetadataCommandList = DetachPartitionCommandList();
+
+	List *detachPartitionCommandList = NIL;
+
+	DetachPartitionCommandList(&detachPartitionCommandList);
+
+	dropMetadataCommandList = list_concat(dropMetadataCommandList,
+										  detachPartitionCommandList);
+
+
 	dropMetadataCommandList = lappend(dropMetadataCommandList,
 									  BREAK_CITUS_TABLE_SEQUENCE_DEPENDENCY_COMMAND);
 	dropMetadataCommandList = lappend(dropMetadataCommandList,
@@ -2657,10 +2666,9 @@ CreateTableMetadataOnWorkers(Oid relationId)
  * an extra step, if there are no partitions to DETACH, this function simply returns
  * empty list to not disable/enable DDL propagation for nothing.
  */
-List *
+void
-DetachPartitionCommandList(void)
+DetachPartitionCommandList(List **detachPartitionCommandList)
 {
-	List *detachPartitionCommandList = NIL;
 	List *distributedTableList = CitusTableList();
 
 	/* we iterate over all distributed partitioned tables and DETACH their partitions */
@@ -2675,26 +2683,24 @@ DetachPartitionCommandList(void)
 		List *partitionList = PartitionList(cacheEntry->relationId);
 		List *detachCommands =
 			GenerateDetachPartitionCommandRelationIdList(partitionList);
-		detachPartitionCommandList = list_concat(detachPartitionCommandList,
+		*detachPartitionCommandList = list_concat(*detachPartitionCommandList,
 												  detachCommands);
 	}
 
-	if (list_length(detachPartitionCommandList) == 0)
+	if (list_length(*detachPartitionCommandList) == 0)
 	{
-		return NIL;
+		return;
 	}
 
-	detachPartitionCommandList =
+	*detachPartitionCommandList =
-		lcons(DISABLE_DDL_PROPAGATION, detachPartitionCommandList);
+		lcons(DISABLE_DDL_PROPAGATION, *detachPartitionCommandList);
 
 	/*
 	 * We probably do not need this but as an extra precaution, we are enabling
 	 * DDL propagation to switch back to original state.
 	 */
-	detachPartitionCommandList = lappend(detachPartitionCommandList,
+	*detachPartitionCommandList = lappend(*detachPartitionCommandList,
 										  ENABLE_DDL_PROPAGATION);
-
-	return detachPartitionCommandList;
 }
 
 

src/backend/distributed/metadata/node_metadata.c

@@ -106,7 +106,7 @@ static void SyncPgDistTableMetadataToNodeList(List *nodeList);
 static List * InterTableRelationshipCommandList();
 static void BlockDistributedQueriesOnMetadataNodes(void);
 static WorkerNode * TupleToWorkerNode(TupleDesc tupleDescriptor, HeapTuple heapTuple);
-static List * PropagateNodeWideObjectsCommandList();
+static void PropagateNodeWideObjectsCommandList(List **nodeWideObjectCommandList);
 static WorkerNode * ModifiableWorkerNode(const char *nodeName, int32 nodePort);
 static bool NodeIsLocal(WorkerNode *worker);
 static void SetLockTimeoutLocally(int32 lock_cooldown);
@@ -759,12 +759,9 @@ PgDistTableMetadataSyncCommandList(void)
  * propagate any object that should be propagated for every node. These are
  * generally not linked to any distributed object but change system wide behaviour.
  */
-static List *
+static void
-PropagateNodeWideObjectsCommandList()
+PropagateNodeWideObjectsCommandList(List **nodeWideObjectCommandList)
 {
-	/* collect all commands */
-	List *ddlCommands = NIL;
-
 	if (EnableAlterRoleSetPropagation)
 	{
 		/*
@@ -772,17 +769,18 @@ PropagateNodeWideObjectsCommandList()
 		 * linked to any role that can be distributed we need to distribute them seperately
 		 */
 		List *alterRoleSetCommands = GenerateAlterRoleSetCommandForRole(InvalidOid);
-		ddlCommands = list_concat(ddlCommands, alterRoleSetCommands);
+		*nodeWideObjectCommandList = list_concat(*nodeWideObjectCommandList,
+												 alterRoleSetCommands);
 	}
 
-	if (list_length(ddlCommands) > 0)
+	if (list_length(*nodeWideObjectCommandList) > 0)
 	{
 		/* if there are command wrap them in enable_ddl_propagation off */
-		ddlCommands = lcons(DISABLE_DDL_PROPAGATION, ddlCommands);
+		*nodeWideObjectCommandList = lcons(DISABLE_DDL_PROPAGATION,
-		ddlCommands = lappend(ddlCommands, ENABLE_DDL_PROPAGATION);
+										   *nodeWideObjectCommandList);
+		*nodeWideObjectCommandList = lappend(*nodeWideObjectCommandList,
+											 ENABLE_DDL_PROPAGATION);
 	}
-
-	return ddlCommands;
 }
 
 
@@ -802,36 +800,43 @@ PropagateNodeWideObjectsCommandList()
  * requires it.
  */
 List *
-SyncDistributedObjectsCommandList(WorkerNode *workerNode)
+SyncDistributedObjectsCommandList(WorkerNode *workerNode, List **commandList)
 {
-	List *commandList = NIL;
-
 	/*
 	 * Propagate node wide objects. It includes only roles for now.
 	 */
-	commandList = list_concat(commandList, PropagateNodeWideObjectsCommandList());
+	List *nodeWideObjectCommandList = NIL;
+	PropagateNodeWideObjectsCommandList(&nodeWideObjectCommandList);
+
+	*commandList = list_concat(*commandList, nodeWideObjectCommandList);
+
 
 	/*
 	 * Detach partitions, break dependencies between sequences and table then
 	 * remove shell tables first.
 	 */
-	commandList = list_concat(commandList, DetachPartitionCommandList());
+	List *detachPartitionCommandList = NIL;
-	commandList = lappend(commandList, BREAK_CITUS_TABLE_SEQUENCE_DEPENDENCY_COMMAND);
+
-	commandList = lappend(commandList, REMOVE_ALL_SHELL_TABLES_COMMAND);
+	DetachPartitionCommandList(&detachPartitionCommandList);
+	*commandList = list_concat(*commandList, detachPartitionCommandList);
+
+
+	*commandList = lappend(*commandList, BREAK_CITUS_TABLE_SEQUENCE_DEPENDENCY_COMMAND);
+	*commandList = lappend(*commandList, REMOVE_ALL_SHELL_TABLES_COMMAND);
 
 	/*
 	 * Replicate all objects of the pg_dist_object to the remote node.
 	 */
-	commandList = list_concat(commandList, ReplicateAllObjectsToNodeCommandList(
+	*commandList = list_concat(*commandList, ReplicateAllObjectsToNodeCommandList(
 								   workerNode->workerName, workerNode->workerPort));
 
 	/*
 	 * After creating each table, handle the inter table relationship between
 	 * those tables.
 	 */
-	commandList = list_concat(commandList, InterTableRelationshipCommandList());
+	*commandList = list_concat(*commandList, InterTableRelationshipCommandList());
 
-	return commandList;
+	return *commandList;
 }
 
 
@@ -875,7 +880,9 @@ SyncDistributedObjectsToNodeList(List *workerNodeList)
 
 	Assert(ShouldPropagate());
 
-	List *commandList = SyncDistributedObjectsCommandList(workerNode);
+	List *commandList = NIL;
+
+	SyncDistributedObjectsCommandList(workerNode, &commandList);
 
 	/* send commands to new workers, the current user should be a superuser */
 	Assert(superuser());

src/backend/distributed/test/metadata_sync.c

@@ -51,7 +51,10 @@ activate_node_snapshot(PG_FUNCTION_ARGS)
 
 	List *updateLocalGroupCommand =
 		list_make1(LocalGroupIdUpdateCommand(dummyWorkerNode->groupId));
-	List *syncDistObjCommands = SyncDistributedObjectsCommandList(dummyWorkerNode);
+
+	List *syncDistObjCommands = NIL;
+	SyncDistributedObjectsCommandList(dummyWorkerNode, &syncDistObjCommands);
+
 	List *dropSnapshotCommands = NodeMetadataDropCommands();
 	List *createSnapshotCommands = NodeMetadataCreateCommands();
 	List *pgDistTableMetadataSyncCommands = PgDistTableMetadataSyncCommandList();

src/include/distributed/metadata_sync.h

@@ -90,7 +90,7 @@ extern char * PlacementUpsertCommand(uint64 shardId, uint64 placementId, int sha
 extern TableDDLCommand * TruncateTriggerCreateCommand(Oid relationId);
 extern void CreateInterTableRelationshipOfRelationOnWorkers(Oid relationId);
 extern List * InterTableRelationshipOfRelationCommandList(Oid relationId);
-extern List * DetachPartitionCommandList(void);
+extern void DetachPartitionCommandList(List **detachPartitionCommandList);
 extern void SyncNodeMetadataToNodes(void);
 extern BackgroundWorkerHandle * SpawnSyncNodeMetadataToNodes(Oid database, Oid owner);
 extern void SyncNodeMetadataToNodesMain(Datum main_arg);

src/include/distributed/worker_manager.h

@@ -105,7 +105,8 @@ extern WorkerNode * SetWorkerColumnLocalOnly(WorkerNode *workerNode, int columnI
 											 Datum value);
 extern uint32 CountPrimariesWithMetadata(void);
 extern WorkerNode * GetFirstPrimaryWorkerNode(void);
-extern List * SyncDistributedObjectsCommandList(WorkerNode *workerNode);
+extern List * SyncDistributedObjectsCommandList(WorkerNode *workerNode,
+												List **commandList);
 extern List * PgDistTableMetadataSyncCommandList(void);
 
 /* Function declarations for worker node utilities */