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MDEV-12580 Wrong query result in join when using an index (Version > "10.2.3")

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JOIN_TAB::remove_redundant_bnl_scan_conds() removes select_cond
from a JOIN_TAB if join cache is enabled, and tab->cache_select->cond
is the equal to tab->select_cond.

But after 8d99166c69 the code to initialize join cache was moved
to happen much later than JOIN_TAB::remove_redundant_bnl_scan_conds(),
and that code might, under certain conditions, revert to *not* using
join cache (set_join_cache_denial()).

If JOIN_TAB::remove_redundant_bnl_scan_conds() removes the WHERE
condition from the JOIN_TAB and later set_join_cache_denial() disables
join cache, we end up with no WHERE condition at all.

Fix: move JOIN_TAB::remove_redundant_bnl_scan_conds() to happen
after all possible set_join_cache_denial() calls.
This commit is contained in:
Sergei Golubchik
2017-05-06 14:00:19 +02:00
parent d6d7e169fb
commit d53eb85997
5 changed files with 38 additions and 15 deletions
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12
mysql-test/t/join_cache.test
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@ -3900,6 +3900,18 @@ SELECT * FROM INFORMATION_SCHEMA.PROFILING, mysql.user WHERE password_expired =
set join_cache_level=default;
#
# MDEV-12580 Wrong query result in join when using an index (Version > "10.2.3")
#
create table t1 (c1 date not null, key (c1)) engine=innodb;
insert t1 values ('2017-12-27');
create table t2 (pk int, f1 int, f2 int);
insert t2 values (4,1,1), (6,1,1);
set join_buffer_size = 222222208;
select f2 from t2,t1 where f2 = 0;
drop table t1, t2;
set join_buffer_size = default;
# The following command must be the last one the file
# this must be the last command in the file
set @@optimizer_switch=@save_optimizer_switch;