Even if some partitions are foreign, allow tuple routing.

This doesn't allow routing tuple to the foreign partitions themselves,
but it permits tuples to be routed to regular partitions despite the
presence of foreign partitions in the same inheritance hierarchy.

Etsuro Fujita, reviewed by Amit Langote and by me.

Discussion: http://postgr.es/m/bc3db4c1-1693-3b8a-559f-33ad2b50b7ad@lab.ntt.co.jp

contrib/file_fdw/input/file_fdw.source

@@ -162,6 +162,27 @@ SELECT tableoid::regclass, * FROM agg FOR UPDATE;
 ALTER FOREIGN TABLE agg_csv NO INHERIT agg;
 DROP TABLE agg;
 
+-- declarative partitioning tests
+SET ROLE regress_file_fdw_superuser;
+CREATE TABLE pt (a int, b text) partition by list (a);
+CREATE FOREIGN TABLE p1 partition of pt for values in (1) SERVER file_server
+OPTIONS (format 'csv', filename '@abs_srcdir@/data/list1.csv', delimiter ',');
+CREATE TABLE p2 partition of pt for values in (2);
+SELECT tableoid::regclass, * FROM pt;
+SELECT tableoid::regclass, * FROM p1;
+SELECT tableoid::regclass, * FROM p2;
+COPY pt FROM '@abs_srcdir@/data/list2.bad' with (format 'csv', delimiter ','); -- ERROR
+COPY pt FROM '@abs_srcdir@/data/list2.csv' with (format 'csv', delimiter ',');
+SELECT tableoid::regclass, * FROM pt;
+SELECT tableoid::regclass, * FROM p1;
+SELECT tableoid::regclass, * FROM p2;
+INSERT INTO pt VALUES (1, 'xyzzy'); -- ERROR
+INSERT INTO pt VALUES (2, 'xyzzy');
+SELECT tableoid::regclass, * FROM pt;
+SELECT tableoid::regclass, * FROM p1;
+SELECT tableoid::regclass, * FROM p2;
+DROP TABLE pt;
+
 -- privilege tests
 SET ROLE regress_file_fdw_superuser;
 SELECT * FROM agg_text ORDER BY a;

contrib/file_fdw/output/file_fdw.source

@@ -289,6 +289,87 @@ SELECT tableoid::regclass, * FROM agg FOR UPDATE;
 
 ALTER FOREIGN TABLE agg_csv NO INHERIT agg;
 DROP TABLE agg;
+-- declarative partitioning tests
+SET ROLE regress_file_fdw_superuser;
+CREATE TABLE pt (a int, b text) partition by list (a);
+CREATE FOREIGN TABLE p1 partition of pt for values in (1) SERVER file_server
+OPTIONS (format 'csv', filename '@abs_srcdir@/data/list1.csv', delimiter ',');
+CREATE TABLE p2 partition of pt for values in (2);
+SELECT tableoid::regclass, * FROM pt;
+ tableoid | a |  b  
+----------+---+-----
+ p1       | 1 | foo
+ p1       | 1 | bar
+(2 rows)
+
+SELECT tableoid::regclass, * FROM p1;
+ tableoid | a |  b  
+----------+---+-----
+ p1       | 1 | foo
+ p1       | 1 | bar
+(2 rows)
+
+SELECT tableoid::regclass, * FROM p2;
+ tableoid | a | b 
+----------+---+---
+(0 rows)
+
+COPY pt FROM '@abs_srcdir@/data/list2.bad' with (format 'csv', delimiter ','); -- ERROR
+ERROR:  cannot route inserted tuples to a foreign table
+CONTEXT:  COPY pt, line 2: "1,qux"
+COPY pt FROM '@abs_srcdir@/data/list2.csv' with (format 'csv', delimiter ',');
+SELECT tableoid::regclass, * FROM pt;
+ tableoid | a |  b  
+----------+---+-----
+ p1       | 1 | foo
+ p1       | 1 | bar
+ p2       | 2 | baz
+ p2       | 2 | qux
+(4 rows)
+
+SELECT tableoid::regclass, * FROM p1;
+ tableoid | a |  b  
+----------+---+-----
+ p1       | 1 | foo
+ p1       | 1 | bar
+(2 rows)
+
+SELECT tableoid::regclass, * FROM p2;
+ tableoid | a |  b  
+----------+---+-----
+ p2       | 2 | baz
+ p2       | 2 | qux
+(2 rows)
+
+INSERT INTO pt VALUES (1, 'xyzzy'); -- ERROR
+ERROR:  cannot route inserted tuples to a foreign table
+INSERT INTO pt VALUES (2, 'xyzzy');
+SELECT tableoid::regclass, * FROM pt;
+ tableoid | a |   b   
+----------+---+-------
+ p1       | 1 | foo
+ p1       | 1 | bar
+ p2       | 2 | baz
+ p2       | 2 | qux
+ p2       | 2 | xyzzy
+(5 rows)
+
+SELECT tableoid::regclass, * FROM p1;
+ tableoid | a |  b  
+----------+---+-----
+ p1       | 1 | foo
+ p1       | 1 | bar
+(2 rows)
+
+SELECT tableoid::regclass, * FROM p2;
+ tableoid | a |   b   
+----------+---+-------
+ p2       | 2 | baz
+ p2       | 2 | qux
+ p2       | 2 | xyzzy
+(3 rows)
+
+DROP TABLE pt;
 -- privilege tests
 SET ROLE regress_file_fdw_superuser;
 SELECT * FROM agg_text ORDER BY a;

src/backend/executor/execMain.c

@@ -1097,8 +1097,9 @@ InitPlan(QueryDesc *queryDesc, int eflags)
  * CheckValidRowMarkRel.
  */
 void
-CheckValidResultRel(Relation resultRel, CmdType operation)
+CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation)
 {
+	Relation	resultRel = resultRelInfo->ri_RelationDesc;
 	TriggerDesc *trigDesc = resultRel->trigdesc;
 	FdwRoutine *fdwroutine;
 
@@ -1169,10 +1170,16 @@ CheckValidResultRel(Relation resultRel, CmdType operation)
 			break;
 		case RELKIND_FOREIGN_TABLE:
 			/* Okay only if the FDW supports it */
-			fdwroutine = GetFdwRoutineForRelation(resultRel, false);
+			fdwroutine = resultRelInfo->ri_FdwRoutine;
 			switch (operation)
 			{
 				case CMD_INSERT:
+					/*
+					 * If foreign partition to do tuple-routing for, skip the
+					 * check; it's disallowed elsewhere.
+					 */
+					if (resultRelInfo->ri_PartitionRoot)
+						break;
 					if (fdwroutine->ExecForeignInsert == NULL)
 						ereport(ERROR,
 								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
@@ -3307,11 +3314,6 @@ ExecSetupPartitionTupleRouting(Relation rel,
 		partrel = heap_open(lfirst_oid(cell), NoLock);
 		part_tupdesc = RelationGetDescr(partrel);
 
-		/*
-		 * Verify result relation is a valid target for the current operation.
-		 */
-		CheckValidResultRel(partrel, CMD_INSERT);
-
 		/*
 		 * Save a tuple conversion map to convert a tuple routed to this
 		 * partition from the parent's type to the partition's.
@@ -3325,8 +3327,10 @@ ExecSetupPartitionTupleRouting(Relation rel,
 						  rel,
 						  estate->es_instrument);
 
-		estate->es_leaf_result_relations =
-			lappend(estate->es_leaf_result_relations, leaf_part_rri);
+		/*
+		 * Verify result relation is a valid target for INSERT.
+		 */
+		CheckValidResultRel(leaf_part_rri, CMD_INSERT);
 
 		/*
 		 * Open partition indices (remember we do not support ON CONFLICT in
@@ -3337,6 +3341,9 @@ ExecSetupPartitionTupleRouting(Relation rel,
 			leaf_part_rri->ri_IndexRelationDescs == NULL)
 			ExecOpenIndices(leaf_part_rri, false);
 
+		estate->es_leaf_result_relations =
+			lappend(estate->es_leaf_result_relations, leaf_part_rri);
+
 		leaf_part_rri++;
 		i++;
 	}

src/backend/executor/nodeModifyTable.c

@@ -1854,7 +1854,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		/*
 		 * Verify result relation is a valid target for the current operation
 		 */
-		CheckValidResultRel(resultRelInfo->ri_RelationDesc, operation);
+		CheckValidResultRel(resultRelInfo, operation);
 
 		/*
 		 * If there are indices on the result relation, open them and save

src/include/executor/executor.h

@@ -177,7 +177,7 @@ extern void ExecutorEnd(QueryDesc *queryDesc);
 extern void standard_ExecutorEnd(QueryDesc *queryDesc);
 extern void ExecutorRewind(QueryDesc *queryDesc);
 extern bool ExecCheckRTPerms(List *rangeTable, bool ereport_on_violation);
-extern void CheckValidResultRel(Relation resultRel, CmdType operation);
+extern void CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation);
 extern void InitResultRelInfo(ResultRelInfo *resultRelInfo,
 				  Relation resultRelationDesc,
 				  Index resultRelationIndex,