Check for Citus table in worker_copy_table_to_node

src/backend/distributed/operations/worker_copy_table_to_node_udf.c

@@ -40,6 +40,15 @@ worker_copy_table_to_node(PG_FUNCTION_ARGS)
 	Oid relationId = PG_GETARG_OID(0);
 	uint32_t targetNodeId = PG_GETARG_INT32(1);
 
+	if (IsCitusTable(relationId))
+	{
+		char *qualifiedRelationName = generate_qualified_relation_name(relationId);
+		ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("table %s is a Citus table, only copies of "
+							   "shards or regular postgres tables are supported",
+							   qualifiedRelationName)));
+	}
+
 	Oid schemaOid = get_rel_namespace(relationId);
 	char *relationSchemaName = get_namespace_name(schemaOid);
 	char *relationName = get_rel_name(relationId);

src/test/regress/expected/worker_copy_table_to_node.out

@@ -37,11 +37,9 @@ CREATE TABLE t_62629600(a int);
 SET search_path TO worker_copy_table_to_node;
 -- Make sure that the UDF doesn't work on Citus tables
 SELECT worker_copy_table_to_node('t', :worker_1_node);
-ERROR:  cannot execute a distributed query from a query on a shard
-DETAIL:  Executing a distributed query in a function call that may be pushed to a remote node can lead to incorrect results.
+ERROR:  table worker_copy_table_to_node.t is a Citus table, only copies of shards or regular postgres tables are supported
 SELECT worker_copy_table_to_node('ref', :worker_1_node);
-ERROR:  cannot execute a distributed query from a query on a shard
-DETAIL:  Executing a distributed query in a function call that may be pushed to a remote node can lead to incorrect results.
+ERROR:  table worker_copy_table_to_node.ref is a Citus table, only copies of shards or regular postgres tables are supported
 -- It should work on shards
 SELECT worker_copy_table_to_node('t_62629600', :worker_1_node);
  worker_copy_table_to_node