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MDEV-17518: Range optimization doesn't use ON expressions from nested outer joins

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Continuation of the fix: Make condition selectivity estimate use the
right estimate, too.
This commit is contained in:
Sergei Petrunia
2018-10-23 13:17:14 +02:00
parent 3b6d903852
commit 14b62b1578
3 changed files with 60 additions and 3 deletions
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32
mysql-test/main/join_outer.result
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@ -2531,5 +2531,37 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10
1 SIMPLE t2 ALL NULL NULL NULL NULL 2
1 SIMPLE t3 range a a 5 NULL 5 Using where
#
# .. part 2: make sure condition selectivity can use the condition too.
#
alter table t3 drop key a;
set @tmp1=@@optimizer_use_condition_selectivity;
set @tmp2=@@use_stat_tables;
set @tmp3=@@histogram_size;
set use_stat_tables=preferably;
set optimizer_use_condition_selectivity=4;
set histogram_size=100;
analyze table t3 persistent for all;
Table Op Msg_type Msg_text
test.t3 analyze status Engine-independent statistics collected
test.t3 analyze status OK
# t3.filtered is less than 100%:
explain extended select * from t1 left join t3 on t1.a=t3.b and t3.a<5;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 100.00
1 SIMPLE t3 ALL NULL NULL NULL NULL 1000 0.99 Using where
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b` from `test`.`t1` left join `test`.`t3` on(`test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t3`.`a` < 5) where 1
# t3.filtered must less than 100%, too:
explain extended select * from t1 left join (t3 join t2) on t1.a=t3.b and t3.a<5;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 100.00
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 100.00
1 SIMPLE t3 ALL NULL NULL NULL NULL 1000 0.99 Using where
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` left join (`test`.`t3` join `test`.`t2`) on(`test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t3`.`a` < 5) where 1
drop table t1,t2,t3;
set optimizer_use_condition_selectivity= @tmp1;
set use_stat_tables= @tmp2;
set histogram_size= @tmp3;
SET optimizer_switch=@save_optimizer_switch;