Ignore partitioned tables when processing ON COMMIT DELETE ROWS

Those tables have no physical storage, making this option unusable with
partition trees as at commit time an actual truncation was attempted.
There are still issues with the way ON COMMIT actions are done when
mixing several action types, however this impacts as well inheritance
trees, so this issue will be dealt with later.

Reported-by: Rajkumar Raghuwanshi
Author: Amit Langote
Reviewed-by: Michael Paquier, Tom Lane
Discussion: https://postgr.es/m/CAKcux6mhgcjSiB_egqEAEFgX462QZtncU8QCAJ2HZwM-wWGVew@mail.gmail.com

src/backend/catalog/heap.c

@@ -3181,6 +3181,13 @@ heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
 
+	/*
+	 * Truncate the relation.  Partitioned tables have no storage, so there is
+	 * nothing to do for them here.
+	 */
+	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+		return;
+
 	/* Truncate the actual file (and discard buffers) */
 	RelationTruncate(rel, 0);
 

src/test/regress/expected/temp.out

@@ -199,3 +199,20 @@ select pg_temp.whoami();
 (1 row)
 
 drop table public.whereami;
+-- For partitioned temp tables, ON COMMIT actions ignore storage-less
+-- partitioned tables.
+begin;
+create temp table temp_parted_oncommit (a int)
+  partition by list (a) on commit delete rows;
+create temp table temp_parted_oncommit_1
+  partition of temp_parted_oncommit
+  for values in (1) on commit delete rows;
+insert into temp_parted_oncommit values (1);
+commit;
+-- partitions are emptied by the previous commit
+select * from temp_parted_oncommit;
+ a 
+---
+(0 rows)
+
+drop table temp_parted_oncommit;

src/test/regress/sql/temp.sql

@@ -151,3 +151,17 @@ select whoami();
 select pg_temp.whoami();
 
 drop table public.whereami;
+
+-- For partitioned temp tables, ON COMMIT actions ignore storage-less
+-- partitioned tables.
+begin;
+create temp table temp_parted_oncommit (a int)
+  partition by list (a) on commit delete rows;
+create temp table temp_parted_oncommit_1
+  partition of temp_parted_oncommit
+  for values in (1) on commit delete rows;
+insert into temp_parted_oncommit values (1);
+commit;
+-- partitions are emptied by the previous commit
+select * from temp_parted_oncommit;
+drop table temp_parted_oncommit;