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MDEV-19245: Impossible WHERE should be noticed earlier after HAVING pushdown

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The bug appears because not all conditions are found to be knowingly
true or false in WHERE after HAVING pushdown optimization.
Impossible WHERE can be found much earlier compared with how it is done now.

To fix it and_new_conditions_to_optimized_cond() is changed.
This commit is contained in:
Galina Shalygina
2019-04-22 16:19:55 +03:00
parent a65d3b2c16
commit a765b19e5c
5 changed files with 89 additions and 12 deletions
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43
mysql-test/main/having_cond_pushdown.result
View File

@ -4733,3 +4733,46 @@ EXPLAIN
}
}
drop table t1;
#
# MDEV-19245: Impossible WHERE should be noticed earlier
# after HAVING pushdown
#
CREATE TABLE t1 (a INT, b INT, c INT);
INSERT INTO t1 VALUES (1,2,1),(3,2,2),(5,6,4),(3,4,1);
EXPLAIN SELECT t1.a,MAX(t1.b) FROM t1
WHERE t1.a > 3 GROUP BY t1.a HAVING t1.a = 3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
EXPLAIN SELECT t1.a,MAX(t1.b) FROM t1
WHERE t1.a = 3 GROUP BY t1.a HAVING t1.a > 3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
EXPLAIN SELECT t1.a,MAX(t1.b) FROM t1
WHERE t1.a > 3 AND t1.a = 3 GROUP BY t1.a ;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
EXPLAIN SELECT t1.a,MAX(t1.b) FROM t1
WHERE (t1.a < 2 OR t1.c > 1) GROUP BY t1.a HAVING t1.a = 3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where
EXPLAIN SELECT t1.a,MAX(t1.b) FROM t1
WHERE t1.a = 3 GROUP BY t1.a HAVING (t1.a < 2 OR t1.a > 3);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
EXPLAIN SELECT t1.a,MAX(t1.b) FROM t1
WHERE t1.a = 3 AND (t1.a < 2 OR t1.a > 3) GROUP BY t1.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
EXPLAIN SELECT t1.a,MAX(t1.b),t1.c FROM t1
WHERE (t1.a < 2 AND t1.c > 1) GROUP BY t1.a HAVING t1.a = 3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
EXPLAIN SELECT t1.a,MAX(t1.b),t1.c FROM t1
WHERE t1.a = 3 GROUP BY t1.a HAVING (t1.a < 2 AND t1.c > 1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
EXPLAIN SELECT t1.a,MAX(t1.b),t1.c FROM t1
WHERE t1.a = 3 AND (t1.a < 2 AND t1.b > 3) GROUP BY t1.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
DROP TABLE t1;