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MDEV-20900: IN predicate to IN subquery conversion causes performance regression

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Disable the IN predicate to IN subquery conversion when the types on the left and
right hand side of the IN predicate are not of comparable type.
This commit is contained in:
Varun Gupta
2019-12-04 20:04:45 +05:30
parent e5e5877740
commit 246e2ae12b
5 changed files with 142 additions and 6 deletions
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31
mysql-test/main/opt_tvc.test
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@ -3,6 +3,7 @@
#
source include/have_debug.inc;
source include/default_optimizer_switch.inc;
source include/have_sequence.inc;
create table t1 (a int, b int);
@ -397,3 +398,33 @@ SELECT * FROM t3 WHERE (f1,f2) IN ((2, 2), (1, 2), (3, 5), (1, 1));
DROP TABLE t1,t2,t3;
SET @@in_predicate_conversion_threshold= default;
--echo #
--echo # MDEV-20900: IN predicate to IN subquery conversion causes performance regression
--echo #
create table t1(a int, b int);
insert into t1 select seq-1, seq-1 from seq_1_to_10;
set in_predicate_conversion_threshold=2;
let $query= select * from t1 where t1.a IN ("1","2","3","4");
eval explain $query;
eval $query;
set in_predicate_conversion_threshold=0;
eval explain $query;
eval $query;
set in_predicate_conversion_threshold=2;
let $query= select * from t1 where (t1.a,t1.b) in (("1","1"),(2,2),(3,3),(4,4));
eval explain $query;
eval $query;
set in_predicate_conversion_threshold=0;
eval explain $query;
eval $query;
drop table t1;
SET @@in_predicate_conversion_threshold= default;