Code review for c94e6942.

validateCheckConstraint() shouldn't try to access the storage for
a partitioned table, because it no longer has any.  Creating a
_RETURN table on a partitioned table shouldn't be allowed, both
because there's no value in it and because trying to do so would
involve a validation scan against its nonexistent storage.

Amit Langote, reviewed by Tom Lane.  Regression test outputs
updated to pass by me.

Discussion: http://postgr.es/m/e5c3cbd3-1551-d6f8-c9e2-51777d632fd2@lab.ntt.co.jp

src/backend/commands/tablecmds.c

@@ -8120,8 +8120,12 @@ validateCheckConstraint(Relation rel, HeapTuple constrtup)
 	bool		isnull;
 	Snapshot	snapshot;
 
-	/* VALIDATE CONSTRAINT is a no-op for foreign tables */
-	if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+	/*
+	 * VALIDATE CONSTRAINT is a no-op for foreign tables and partitioned
+	 * tables.
+	 */
+	if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE ||
+		rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
 	constrForm = (Form_pg_constraint) GETSTRUCT(constrtup);

src/backend/rewrite/rewriteDefine.c

@@ -422,6 +422,12 @@ DefineQueryRewrite(char *rulename,
 			HeapScanDesc scanDesc;
 			Snapshot	snapshot;
 
+			if (event_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+				ereport(ERROR,
+						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+						 errmsg("could not convert partitioned table \"%s\" to a view",
+								RelationGetRelationName(event_relation))));
+
 			snapshot = RegisterSnapshot(GetLatestSnapshot());
 			scanDesc = heap_beginscan(event_relation, snapshot, 0, NULL);
 			if (heap_getnext(scanDesc, ForwardScanDirection) != NULL)

src/test/regress/expected/alter_table.out

@@ -3372,3 +3372,9 @@ ERROR:  partition constraint is violated by some row
 -- cleanup
 drop table p;
 drop table p1;
+-- validate constraint on partitioned tables should only scan leaf partitions
+create table parted_validate_test (a int) partition by list (a);
+create table parted_validate_test_1 partition of parted_validate_test for values in (0, 1);
+alter table parted_validate_test add constraint parted_validate_test_chka check (a > 0) not valid;
+alter table parted_validate_test validate constraint parted_validate_test_chka;
+drop table parted_validate_test;

src/test/regress/expected/rules.out

@@ -2574,6 +2574,11 @@ select reltoastrelid, relkind, relfrozenxid
 (1 row)
 
 drop view fooview;
+-- trying to convert a partitioned table to view is not allowed
+create table fooview (x int, y text) partition by list (x);
+create rule "_RETURN" as on select to fooview do instead
+  select 1 as x, 'aaa'::text as y;
+ERROR:  could not convert partitioned table "fooview" to a view
 --
 -- check for planner problems with complex inherited UPDATES
 --

src/test/regress/sql/alter_table.sql

@@ -2228,3 +2228,10 @@ alter table p attach partition p1 for values from (1, 2) to (1, 10);
 -- cleanup
 drop table p;
 drop table p1;
+
+-- validate constraint on partitioned tables should only scan leaf partitions
+create table parted_validate_test (a int) partition by list (a);
+create table parted_validate_test_1 partition of parted_validate_test for values in (0, 1);
+alter table parted_validate_test add constraint parted_validate_test_chka check (a > 0) not valid;
+alter table parted_validate_test validate constraint parted_validate_test_chka;
+drop table parted_validate_test;

src/test/regress/sql/rules.sql

@@ -898,6 +898,11 @@ select reltoastrelid, relkind, relfrozenxid
 
 drop view fooview;
 
+-- trying to convert a partitioned table to view is not allowed
+create table fooview (x int, y text) partition by list (x);
+create rule "_RETURN" as on select to fooview do instead
+  select 1 as x, 'aaa'::text as y;
+
 --
 -- check for planner problems with complex inherited UPDATES
 --