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Fixed bug mdev-7316.

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The function table_cond_selectivity() should take into account that condition selectivity
for some fields can be set to 0.
This commit is contained in:
Igor Babaev
2015-02-05 20:09:08 -08:00
parent 826d7c68d2
commit 587c72088c
4 changed files with 104 additions and 2 deletions
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30
mysql-test/r/selectivity_innodb.result
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@ -1419,6 +1419,36 @@ Note 1003 select `test`.`a`.`a` AS `a`,`test`.`a`.`b` AS `b`,`test`.`b`.`a` AS `
set histogram_size=@save_histogram_size;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
drop table t0,t1,t2;
#
# Bug mdev-7316: a conjunct in WHERE with selectivity == 0
#
CREATE TABLE t1 (a varchar(16), b int, PRIMARY KEY(a), KEY(b)) ENGINE=INNODB;
INSERT INTO t1 VALUES
('USAChinese',10), ('USAEnglish',20), ('USAFrench',30);
CREATE TABLE t2 (i int) ENGINE=INNODB;
INSERT INTO t2 VALUES
(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(1),(2),(3),(4);
ANALYZE TABLE t1, t2;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
test.t2 analyze status Engine-independent statistics collected
test.t2 analyze status OK
set use_stat_tables='preferably';
set optimizer_use_condition_selectivity=3;
EXPLAIN EXTENDED
SELECT * FROM t1, t2
WHERE a <> 'USARussian' AND b IS NULL;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ref PRIMARY,b b 5 const 2 66.67 Using where; Using index
1 SIMPLE t2 ALL NULL NULL NULL NULL 14 100.00 Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`i` AS `i` from `test`.`t1` join `test`.`t2` where ((`test`.`t1`.`a` <> 'USARussian') and isnull(`test`.`t1`.`b`))
SELECT * FROM t1, t2
WHERE a <> 'USARussian' AND b IS NULL;
a b i
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
DROP TABLE t1,t2;
set use_stat_tables=@save_use_stat_tables;
set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
set @tmp_ust= @@use_stat_tables;