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Fixed bug #54539.

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Added a possibility not to factor out the condition pushed to
the access index out of the condition pushed to a joined table.
This is useful for the condition pushed to the index when a hashed
join buffer for BKA is employed. In this case the index condition
may be false for some, but for all records with the same key.
So the condition must be checked not only after index lookup,
but after fetching row data as well, and it makes sense not to 
factor out the condition from the condition checked after reading
row data,
The bug happened because the condition pushed to an index always
was factor out from the condition pushed to the accessed table.
This commit is contained in:
Igor Babaev
2010-10-01 10:08:10 -07:00
parent 21b1b5f040
commit 1320f6073c
5 changed files with 91 additions and 14 deletions
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28
mysql-test/t/join_cache.test
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@@ -2076,5 +2076,33 @@ SELECT t2.a FROM t1 LEFT JOIN t2 ON t2.b = t1.b;
set join_cache_level = default;
DROP TABLE t1,t2;
--echo #
--echo # BUG#54359 "Extra rows with join_cache_level=7,8 and two joins
--echo # --and multi-column index"
--echo #
CREATE TABLE t1 (
pk int NOT NULL,
a int DEFAULT NULL,
b varchar(16) DEFAULT NULL,
c varchar(16) DEFAULT NULL,
INDEX idx (b,a))
;
INSERT INTO t1 VALUES (4,9,'k','k');
INSERT INTO t1 VALUES (12,5,'k','k');
set join_cache_level = 8;
EXPLAIN
SELECT t.a FROM t1 t, t1 s FORCE INDEX(idx)
WHERE s.pk AND s.a >= t.pk AND s.b = t.c;
SELECT t.a FROM t1 t, t1 s FORCE INDEX(idx)
WHERE s.pk AND s.a >= t.pk AND s.b = t.c;
set join_cache_level = default;
DROP TABLE t1;
# this must be the last command in the file
set @@optimizer_switch=@save_optimizer_switch;