allow "alter schema rename to / owner to" from any node

src/backend/distributed/commands/common.c

@@ -31,6 +31,13 @@
 #include "distributed/worker_transaction.h"
 
 
+static List * PreprocessAlterDistributedObjectStmtInternal(Node *stmt,
+														   const char *queryString,
+														   ProcessUtilityContext
+														   processUtilityContext,
+														   bool allowFromWorkers);
+
+
 /*
  * PostprocessCreateDistributedObjectFromCatalogStmt is a common function that can be used
  * for most objects during their creation phase. After the creation has happened locally
@@ -104,9 +111,39 @@ PostprocessCreateDistributedObjectFromCatalogStmt(Node *stmt, const char *queryS
 
 
 /*
- * PreprocessAlterDistributedObjectStmtFromCoordinator handles any updates to distributed
+ * PreprocessAlterDistributedObjectStmtFromCoordinator is a wrapper around
- * objects by creating the fully qualified sql to apply to all workers after checking all
+ * PreprocessAlterDistributedObjectStmtInternal to be used when altering distributed
- * predconditions that apply to propagating changes.
+ * objects that we allow altering only from the coordinator.
+ */
+List *
+PreprocessAlterDistributedObjectStmtFromCoordinator(Node *stmt, const char *queryString,
+													ProcessUtilityContext
+													processUtilityContext)
+{
+	return PreprocessAlterDistributedObjectStmtInternal(stmt, queryString,
+														processUtilityContext, false);
+}
+
+
+/*
+ * PreprocessAlterDistributedObjectStmtFromCoordinator is a wrapper around
+ * PreprocessAlterDistributedObjectStmtInternal to be used when altering distributed
+ * objects that we allow altering only from the coordinator.
+ */
+List *
+PreprocessAlterDistributedObjectStmtAnyNodes(Node *stmt, const char *queryString,
+											 ProcessUtilityContext
+											 processUtilityContext)
+{
+	return PreprocessAlterDistributedObjectStmtInternal(stmt, queryString,
+														processUtilityContext, true);
+}
+
+
+/*
+ * PreprocessAlterDistributedObjectStmtInternal handles any updates to distributed
+ * objects by creating the fully qualified sql to apply to all other nodes after checking
+ * all predconditions that apply to propagating changes.
  *
  * Preconditions are (in order):
  *  - not in a CREATE/ALTER EXTENSION code block
@@ -114,18 +151,18 @@ PostprocessCreateDistributedObjectFromCatalogStmt(Node *stmt, const char *queryS
  *  - object being altered is distributed
  *  - any object specific feature flag is turned on when a feature flag is available
  *
- * Once we conclude to propagate the changes to the workers we make sure that the command
+ * Once we conclude to propagate the changes to other nodes we make sure that the command
- * has been executed on the coordinator and force any ongoing transaction to run in
+ * has been executed on the local node and force any ongoing transaction to run in
  * sequential mode. If any of these steps fail we raise an error to inform the user.
  *
  * Lastly we recreate a fully qualified version of the original sql and prepare the tasks
- * to send these sql commands to the workers. These tasks include instructions to prevent
+ * to send these sql commands to other nodes. These tasks include instructions to prevent
  * recursion of propagation with Citus' MX functionality.
  */
-List *
+static List *
-PreprocessAlterDistributedObjectStmtFromCoordinator(Node *stmt, const char *queryString,
+PreprocessAlterDistributedObjectStmtInternal(Node *stmt, const char *queryString,
-													ProcessUtilityContext
+											 ProcessUtilityContext processUtilityContext,
-													processUtilityContext)
+											 bool allowFromWorkers)
 {
 	const DistributeObjectOps *ops = GetDistributeObjectOps(stmt);
 	Assert(ops != NULL);
@@ -146,7 +183,15 @@ PreprocessAlterDistributedObjectStmtFromCoordinator(Node *stmt, const char *quer
 		return NIL;
 	}
 
-	EnsureCoordinator();
+	if (allowFromWorkers)
+	{
+		EnsurePropagationToCoordinator();
+	}
+	else
+	{
+		EnsureCoordinator();
+	}
+
 	EnsureSequentialMode(ops->objectType);
 
 	QualifyTreeNode(stmt);
@@ -156,7 +201,7 @@ PreprocessAlterDistributedObjectStmtFromCoordinator(Node *stmt, const char *quer
 								(void *) sql,
 								ENABLE_DDL_PROPAGATION);
 
-	return NodeDDLTaskList(NON_COORDINATOR_NODES, commands);
+	return NodeDDLTaskList(REMOTE_NODES, commands);
 }
 
 

src/backend/distributed/commands/distribute_object_ops.c

@@ -1190,7 +1190,7 @@ static DistributeObjectOps Routine_Rename = {
 static DistributeObjectOps Schema_AlterOwner = {
 	.deparse = DeparseAlterSchemaOwnerStmt,
 	.qualify = NULL,
-	.preprocess = PreprocessAlterDistributedObjectStmtFromCoordinator,
+	.preprocess = PreprocessAlterDistributedObjectStmtAnyNodes,
 	.operationType = DIST_OPS_ALTER,
 	.postprocess = NULL,
 	.address = AlterSchemaOwnerStmtObjectAddress,
@@ -1217,7 +1217,7 @@ static DistributeObjectOps Schema_Grant = {
 static DistributeObjectOps Schema_Rename = {
 	.deparse = DeparseAlterSchemaRenameStmt,
 	.qualify = NULL,
-	.preprocess = PreprocessAlterDistributedObjectStmtFromCoordinator,
+	.preprocess = PreprocessAlterDistributedObjectStmtAnyNodes,
 	.postprocess = NULL,
 	.objectType = OBJECT_SCHEMA,
 	.operationType = DIST_OPS_ALTER,

src/include/distributed/commands.h

@@ -191,6 +191,10 @@ extern List * PreprocessAlterDistributedObjectStmtFromCoordinator(Node *stmt,
 																  const char *queryString,
 																  ProcessUtilityContext
 																  processUtilityContext);
+extern List * PreprocessAlterDistributedObjectStmtAnyNodes(Node *stmt,
+														   const char *queryString,
+														   ProcessUtilityContext
+														   processUtilityContext);
 extern List * PostprocessAlterDistributedObjectStmtFromCoordinator(Node *stmt,
 																   const char *queryString);
 extern List * PreprocessDropDistributedObjectStmt(Node *node, const char *queryString,

src/test/regress/expected/multi_mx_schema_support.out

@@ -487,9 +487,16 @@ SELECT table_schema AS "Shards' Schema"
 (1 row)
 
 -- Show that altering distributed schema is not allowed on worker nodes
+-- when the coordinator is not in the metadata.
+SELECT COUNT(*)=0 FROM pg_dist_node WHERE groupid = 0; -- verify that the coordinator is not in the metadata
+ ?column?
+---------------------------------------------------------------------
+ t
+(1 row)
+
 ALTER SCHEMA mx_old_schema RENAME TO temp_mx_old_schema;
-ERROR:  operation is not allowed on this node
+ERROR:  coordinator is not added to the metadata
-HINT:  Connect to the coordinator and run it again.
+HINT:  Use SELECT citus_set_coordinator_host('<hostname>') on coordinator to configure the coordinator hostname
 \c - - - :master_port
 ALTER TABLE mx_old_schema.table_set_schema SET SCHEMA mx_new_schema;
 SELECT objid::oid::regnamespace::text as "Distributed Schemas"

src/test/regress/sql/multi_mx_schema_support.sql

@@ -321,6 +321,8 @@ SELECT table_schema AS "Shards' Schema"
     GROUP BY table_schema;
 
 -- Show that altering distributed schema is not allowed on worker nodes
+-- when the coordinator is not in the metadata.
+SELECT COUNT(*)=0 FROM pg_dist_node WHERE groupid = 0; -- verify that the coordinator is not in the metadata
 ALTER SCHEMA mx_old_schema RENAME TO temp_mx_old_schema;
 \c - - - :master_port