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Forbid SJE with result relation

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The target relation for INSERT/UPDATE/DELETE/MERGE has a different behavior
than other relations in EvalPlanQual() and RETURNING clause.  This is why we
forbid target relation to be either source or target relation in SJE.
It's not clear if we could ever support this.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/b9e8f460-f9a6-0e9b-e8ba-60d59f0bc22c%40gmail.com
pull/152/head
Alexander Korotkov 1 year ago
parent 30b4955a46
commit 8c441c0827
4 changed files with 84 additions and 48 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 11
      src/backend/optimizer/plan/analyzejoins.c
  2. 72
      src/test/regress/expected/join.out
  3. 9
      src/test/regress/expected/updatable_views.out
  4. 28
      src/test/regress/sql/join.sql

11
src/backend/optimizer/plan/analyzejoins.c
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@ -2086,6 +2086,14 @@ remove_self_joins_one_group(PlannerInfo *root, Relids relids)
{
RelOptInfo *inner = root->simple_rel_array[r];
/*
* We don't accept result relation as either source or target relation
* of SJE, because result relation has different behavior in
* EvalPlanQual() and RETURNING clause.
*/
if (root->parse->resultRelation == r)
continue;
k = r;
while ((k = bms_next_member(relids, k)) > 0)
@ -2101,6 +2109,9 @@ remove_self_joins_one_group(PlannerInfo *root, Relids relids)
PlanRowMark *imark = NULL;
List *uclauses = NIL;
if (root->parse->resultRelation == k)
continue;
/* A sanity check: the relations have the same Oid. */
Assert(root->simple_rte_array[k]->relid ==
root->simple_rte_array[r]->relid);

72
src/test/regress/expected/join.out
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@ -6868,18 +6868,58 @@ select * from emp1 t1
-> Seq Scan on emp1 t3
(6 rows)
-- Check that SJE replaces target relation correctly
-- Check that SJE doesn't replace the target relation
explain (costs off)
WITH t1 AS (SELECT * FROM emp1)
UPDATE emp1 SET code = t1.code + 1 FROM t1
WHERE t1.id = emp1.id RETURNING emp1.id, emp1.code;
WHERE t1.id = emp1.id RETURNING emp1.id, emp1.code, t1.code;
QUERY PLAN
----------------------------------
-------------------------------------------------------
Update on emp1
-> Nested Loop
-> Seq Scan on emp1
Filter: (id IS NOT NULL)
(3 rows)
-> Index Scan using emp1_pkey on emp1 emp1_1
Index Cond: (id = emp1.id)
(5 rows)
INSERT INTO emp1 VALUES (1, 1), (2, 1);
WITH t1 AS (SELECT * FROM emp1)
UPDATE emp1 SET code = t1.code + 1 FROM t1
WHERE t1.id = emp1.id RETURNING emp1.id, emp1.code, t1.code;
id | code | code
----+------+------
1 | 2 | 1
2 | 2 | 1
(2 rows)
TRUNCATE emp1;
EXPLAIN (COSTS OFF)
UPDATE sj sq SET b = 1 FROM sj as sz WHERE sq.a = sz.a;
QUERY PLAN
-------------------------------------
Update on sj sq
-> Nested Loop
Join Filter: (sq.a = sz.a)
-> Seq Scan on sj sq
-> Materialize
-> Seq Scan on sj sz
(6 rows)
CREATE RULE sj_del_rule AS ON DELETE TO sj
DO INSTEAD
UPDATE sj SET a = 1 WHERE a = old.a;
EXPLAIN (COSTS OFF) DELETE FROM sj;
QUERY PLAN
--------------------------------------
Update on sj sj_1
-> Nested Loop
Join Filter: (sj.a = sj_1.a)
-> Seq Scan on sj sj_1
-> Materialize
-> Seq Scan on sj
(6 rows)
DROP RULE sj_del_rule ON sj CASCADE;
-- Check that SJE does not mistakenly omit qual clauses (bug #18187)
insert into emp1 values (1, 1);
explain (costs off)
@ -7076,7 +7116,6 @@ ON sj_t1.id = _t2t3t4.id;
--
-- Test RowMarks-related code
--
-- TODO: Why this select returns two copies of ctid field? Should we fix it?
EXPLAIN (COSTS OFF) -- Both sides have explicit LockRows marks
SELECT a1.a FROM sj a1,sj a2 WHERE (a1.a=a2.a) FOR UPDATE;
QUERY PLAN
@ -7086,27 +7125,6 @@ SELECT a1.a FROM sj a1,sj a2 WHERE (a1.a=a2.a) FOR UPDATE;
Filter: (a IS NOT NULL)
(3 rows)
EXPLAIN (COSTS OFF) -- A RowMark exists for the table being kept
UPDATE sj sq SET b = 1 FROM sj as sz WHERE sq.a = sz.a;
QUERY PLAN
---------------------------------
Update on sj sz
-> Seq Scan on sj sz
Filter: (a IS NOT NULL)
(3 rows)
CREATE RULE sj_del_rule AS ON DELETE TO sj
DO INSTEAD
UPDATE sj SET a = 1 WHERE a = old.a;
EXPLAIN (COSTS OFF) DELETE FROM sj; -- A RowMark exists for the table being dropped
QUERY PLAN
---------------------------------
Update on sj
-> Seq Scan on sj
Filter: (a IS NOT NULL)
(3 rows)
DROP RULE sj_del_rule ON sj CASCADE;
reset enable_hashjoin;
reset enable_mergejoin;
--

9
src/test/regress/expected/updatable_views.out
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@ -2500,12 +2500,15 @@ SELECT * FROM rw_view1;
EXPLAIN (costs off) DELETE FROM rw_view1 WHERE id = 1 AND snoop(data);
QUERY PLAN
--------------------------------------------------
Update on base_tbl
-------------------------------------------------------------------
Update on base_tbl base_tbl_1
-> Nested Loop
-> Index Scan using base_tbl_pkey on base_tbl base_tbl_1
Index Cond: (id = 1)
-> Index Scan using base_tbl_pkey on base_tbl
Index Cond: (id = 1)
Filter: ((NOT deleted) AND snoop(data))
(4 rows)
(7 rows)
DELETE FROM rw_view1 WHERE id = 1 AND snoop(data);
NOTICE: snooped value: Row 1

28
src/test/regress/sql/join.sql
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@ -2616,11 +2616,25 @@ select * from emp1 t1
inner join emp1 t2 on t1.id = t2.id
left join emp1 t3 on t1.id > 1 and t1.id < 2;
-- Check that SJE replaces target relation correctly
-- Check that SJE doesn't replace the target relation
explain (costs off)
WITH t1 AS (SELECT * FROM emp1)
UPDATE emp1 SET code = t1.code + 1 FROM t1
WHERE t1.id = emp1.id RETURNING emp1.id, emp1.code;
WHERE t1.id = emp1.id RETURNING emp1.id, emp1.code, t1.code;
INSERT INTO emp1 VALUES (1, 1), (2, 1);
WITH t1 AS (SELECT * FROM emp1)
UPDATE emp1 SET code = t1.code + 1 FROM t1
WHERE t1.id = emp1.id RETURNING emp1.id, emp1.code, t1.code;
TRUNCATE emp1;
EXPLAIN (COSTS OFF)
UPDATE sj sq SET b = 1 FROM sj as sz WHERE sq.a = sz.a;
CREATE RULE sj_del_rule AS ON DELETE TO sj
DO INSTEAD
UPDATE sj SET a = 1 WHERE a = old.a;
EXPLAIN (COSTS OFF) DELETE FROM sj;
DROP RULE sj_del_rule ON sj CASCADE;
-- Check that SJE does not mistakenly omit qual clauses (bug #18187)
insert into emp1 values (1, 1);
@ -2729,19 +2743,9 @@ ON sj_t1.id = _t2t3t4.id;
-- Test RowMarks-related code
--
-- TODO: Why this select returns two copies of ctid field? Should we fix it?
EXPLAIN (COSTS OFF) -- Both sides have explicit LockRows marks
SELECT a1.a FROM sj a1,sj a2 WHERE (a1.a=a2.a) FOR UPDATE;
EXPLAIN (COSTS OFF) -- A RowMark exists for the table being kept
UPDATE sj sq SET b = 1 FROM sj as sz WHERE sq.a = sz.a;
CREATE RULE sj_del_rule AS ON DELETE TO sj
DO INSTEAD
UPDATE sj SET a = 1 WHERE a = old.a;
EXPLAIN (COSTS OFF) DELETE FROM sj; -- A RowMark exists for the table being dropped
DROP RULE sj_del_rule ON sj CASCADE;
reset enable_hashjoin;
reset enable_mergejoin;

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