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Merge of fix for Bug#50394.

This commit is contained in:
Martin Hansson
2010-09-13 14:46:55 +02:00
3 changed files with 55 additions and 0 deletions

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@@ -1617,6 +1617,27 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 2 Using where; Using temporary; Using filesort
1 SIMPLE t2 ALL NULL NULL NULL NULL 10 Using join buffer
DROP TABLE t1, t2;
#
# Bug #50394: Regression in EXPLAIN with index scan, LIMIT, GROUP BY and
# ORDER BY computed col
#
CREATE TABLE t1 ( a INT NOT NULL, b INT NOT NULL, KEY( a, b ) );
INSERT INTO t1 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5);
INSERT INTO t1 SELECT a + 5, b + 5 FROM t1;
CREATE TABLE t2( a INT PRIMARY KEY, b INT );
INSERT INTO t2 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5);
INSERT INTO t2 SELECT a + 5, b + 5 FROM t2;
EXPLAIN
SELECT count(*) AS c, t1.a
FROM t1 JOIN t2 ON t1.b = t2.a
WHERE t2.b = 1
GROUP BY t1.a
ORDER by c
LIMIT 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 8 NULL 10 Using index; Using temporary; Using filesort
1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 Using where
DROP TABLE t1, t2;
End of 5.1 tests
#
# Bug #38745: MySQL 5.1 optimizer uses filesort for ORDER BY