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Fix Memoize to work with partitionwise joining.

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A couple of places weren't up to speed for this.  By sheer good
luck, we didn't fail but just selected a non-memoized join plan,
at least in the test case we have.  Nonetheless, it's a bug,
and I'm not quite sure that it couldn't have worse consequences
in other examples.  So back-patch to v14 where Memoize came in.

Richard Guo

Discussion: https://postgr.es/m/CAMbWs48GkNom272sfp0-WeD6_0HSR19BJ4H1c9ZKSfbVnJsvRg@mail.gmail.com
This commit is contained in:
Tom Lane
2022-12-05 12:36:41 -05:00
parent 1bd84ef677
commit dc3648f65b
5 changed files with 74 additions and 3 deletions
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39
src/test/regress/expected/memoize.out
View File

@@ -196,6 +196,45 @@ SELECT * FROM strtest s1 INNER JOIN strtest s2 ON s1.t >= s2.t;', false);
(8 rows)
DROP TABLE strtest;
-- Ensure memoize works with partitionwise join
SET enable_partitionwise_join TO on;
CREATE TABLE prt (a int) PARTITION BY RANGE(a);
CREATE TABLE prt_p1 PARTITION OF prt FOR VALUES FROM (0) TO (10);
CREATE TABLE prt_p2 PARTITION OF prt FOR VALUES FROM (10) TO (20);
INSERT INTO prt VALUES (0), (0), (0), (0);
INSERT INTO prt VALUES (10), (10), (10), (10);
CREATE INDEX iprt_p1_a ON prt_p1 (a);
CREATE INDEX iprt_p2_a ON prt_p2 (a);
ANALYZE prt;
SELECT explain_memoize('
SELECT * FROM prt t1 INNER JOIN prt t2 ON t1.a = t2.a;', false);
explain_memoize
------------------------------------------------------------------------------------------
Append (actual rows=32 loops=N)
-> Nested Loop (actual rows=16 loops=N)
-> Index Only Scan using iprt_p1_a on prt_p1 t1_1 (actual rows=4 loops=N)
Heap Fetches: N
-> Memoize (actual rows=4 loops=N)
Cache Key: t1_1.a
Cache Mode: logical
Hits: 3 Misses: 1 Evictions: Zero Overflows: 0 Memory Usage: NkB
-> Index Only Scan using iprt_p1_a on prt_p1 t2_1 (actual rows=4 loops=N)
Index Cond: (a = t1_1.a)
Heap Fetches: N
-> Nested Loop (actual rows=16 loops=N)
-> Index Only Scan using iprt_p2_a on prt_p2 t1_2 (actual rows=4 loops=N)
Heap Fetches: N
-> Memoize (actual rows=4 loops=N)
Cache Key: t1_2.a
Cache Mode: logical
Hits: 3 Misses: 1 Evictions: Zero Overflows: 0 Memory Usage: NkB
-> Index Only Scan using iprt_p2_a on prt_p2 t2_2 (actual rows=4 loops=N)
Index Cond: (a = t1_2.a)
Heap Fetches: N
(21 rows)
DROP TABLE prt;
RESET enable_partitionwise_join;
-- Exercise Memoize code that flushes the cache when a parameter changes which
-- is not part of the cache key.
-- Ensure we get a Memoize plan

19
src/test/regress/sql/memoize.sql
View File

@@ -103,6 +103,25 @@ SELECT * FROM strtest s1 INNER JOIN strtest s2 ON s1.t >= s2.t;', false);
DROP TABLE strtest;
-- Ensure memoize works with partitionwise join
SET enable_partitionwise_join TO on;
CREATE TABLE prt (a int) PARTITION BY RANGE(a);
CREATE TABLE prt_p1 PARTITION OF prt FOR VALUES FROM (0) TO (10);
CREATE TABLE prt_p2 PARTITION OF prt FOR VALUES FROM (10) TO (20);
INSERT INTO prt VALUES (0), (0), (0), (0);
INSERT INTO prt VALUES (10), (10), (10), (10);
CREATE INDEX iprt_p1_a ON prt_p1 (a);
CREATE INDEX iprt_p2_a ON prt_p2 (a);
ANALYZE prt;
SELECT explain_memoize('
SELECT * FROM prt t1 INNER JOIN prt t2 ON t1.a = t2.a;', false);
DROP TABLE prt;
RESET enable_partitionwise_join;
-- Exercise Memoize code that flushes the cache when a parameter changes which
-- is not part of the cache key.