MariaDB

  1. Bug #725050
  2. Comment #3

Comment 3 for bug 725050

Revision history for this message
Timour Katchaounov (timour) wrote : Re: Carsh with join_cache_hashed with semijoin and join_cache_level=3

Reduced test case.
It turns out that in 5.3 there is no need for
all the subquery levels, 2 are enough.

create table t1 (a int not null);

set @@optimizer_switch='join_cache_hashed=on,semijoin=on';
set join_cache_level=3;

SET @@debug = 'd:t:O,/tmp/trace.out';

explain
select a from t1 where a in ( select a from t1);

drop table t1;