Split handling of reloptions for partitioned tables

Partitioned tables do not have relation options yet, but, similarly to
what's done for views which have their own parsing table, it could make
sense to introduce new parameters for some of the existing default ones
like fillfactor, autovacuum, etc.  Splitting things has the advantage to
make the information stored in rd_options include only the necessary
information, reducing the amount of memory used for a relcache entry
with partitioned tables if new reloptions are introduced at this level.

Author:  Nikolay Shaplov
Reviewed-by: Amit Langote, Michael Paquier
Discussion: https://postgr.es/m/1627387.Qykg9O6zpu@x200m

src/backend/access/common/reloptions.c

@@ -1099,9 +1099,11 @@ extractRelOptions(HeapTuple tuple, TupleDesc tupdesc,
 		case RELKIND_RELATION:
 		case RELKIND_TOASTVALUE:
 		case RELKIND_MATVIEW:
-		case RELKIND_PARTITIONED_TABLE:
 			options = heap_reloptions(classForm->relkind, datum, false);
 			break;
+		case RELKIND_PARTITIONED_TABLE:
+			options = partitioned_table_reloptions(datum, false);
+			break;
 		case RELKIND_VIEW:
 			options = view_reloptions(datum, false);
 			break;
@@ -1571,6 +1573,21 @@ build_reloptions(Datum reloptions, bool validate,
 	return rdopts;
 }
 
+/*
+ * Option parser for partitioned tables
+ */
+bytea *
+partitioned_table_reloptions(Datum reloptions, bool validate)
+{
+	/*
+	 * There are no options for partitioned tables yet, but this is able to do
+	 * some validation.
+	 */
+	return (bytea *) build_reloptions(reloptions, validate,
+									  RELOPT_KIND_PARTITIONED,
+									  0, NULL, 0);
+}
+
 /*
  * Option parser for views
  */
@@ -1614,9 +1631,6 @@ heap_reloptions(char relkind, Datum reloptions, bool validate)
 		case RELKIND_RELATION:
 		case RELKIND_MATVIEW:
 			return default_reloptions(reloptions, validate, RELOPT_KIND_HEAP);
-		case RELKIND_PARTITIONED_TABLE:
-			return default_reloptions(reloptions, validate,
-									  RELOPT_KIND_PARTITIONED);
 		default:
 			/* other relkinds are not supported */
 			return NULL;

src/backend/commands/tablecmds.c

@@ -719,10 +719,17 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
-	if (relkind == RELKIND_VIEW)
-		(void) view_reloptions(reloptions, true);
-	else
-		(void) heap_reloptions(relkind, reloptions, true);
+	switch (relkind)
+	{
+		case RELKIND_VIEW:
+			(void) view_reloptions(reloptions, true);
+			break;
+		case RELKIND_PARTITIONED_TABLE:
+			(void) partitioned_table_reloptions(reloptions, true);
+			break;
+		default:
+			(void) heap_reloptions(relkind, reloptions, true);
+	}
 
 	if (stmt->ofTypename)
 	{
@@ -12187,9 +12194,11 @@ ATExecSetRelOptions(Relation rel, List *defList, AlterTableType operation,
 		case RELKIND_RELATION:
 		case RELKIND_TOASTVALUE:
 		case RELKIND_MATVIEW:
-		case RELKIND_PARTITIONED_TABLE:
 			(void) heap_reloptions(rel->rd_rel->relkind, newOptions, true);
 			break;
+		case RELKIND_PARTITIONED_TABLE:
+			(void) partitioned_table_reloptions(newOptions, true);
+			break;
 		case RELKIND_VIEW:
 			(void) view_reloptions(newOptions, true);
 			break;

src/include/access/reloptions.h

@@ -306,6 +306,7 @@ extern bytea *default_reloptions(Datum reloptions, bool validate,
 								 relopt_kind kind);
 extern bytea *heap_reloptions(char relkind, Datum reloptions, bool validate);
 extern bytea *view_reloptions(Datum reloptions, bool validate);
+extern bytea *partitioned_table_reloptions(Datum reloptions, bool validate);
 extern bytea *index_reloptions(amoptions_function amoptions, Datum reloptions,
 							   bool validate);
 extern bytea *attribute_reloptions(Datum reloptions, bool validate);