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MDEV-9602 crash in st_key::actual_rec_per_key when group by constant

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Problem was that cost_group_min_max() could not handle if group by was optimized away.
This commit is contained in:
Monty 2016-04-27 16:37:01 +03:00
parent 646c4cea58
commit 48f02af761
3 changed files with 35 additions and 1 deletions
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14
mysql-test/r/group_by.result
View File

@ -2678,3 +2678,17 @@ NULL
100098
100099
drop table t0,t1,t2;
#
# MDEV-9602 crash in st_key::actual_rec_per_key when group by constant
#
create table t1 (a date not null,unique (a)) engine=innodb;
Warnings:
Warning 1286 Unknown storage engine 'innodb'
Warning 1266 Using storage engine MyISAM for table 't1'
select distinct a from t1 group by 'a';
a
insert into t1 values("2001-02-02"),("2001-02-03");
select distinct a from t1 group by 'a';
a
2001-02-02
drop table t1;

10
mysql-test/t/group_by.test
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@ -1793,3 +1793,13 @@ from t1
group by t1.b;
drop table t0,t1,t2;
--echo #
--echo # MDEV-9602 crash in st_key::actual_rec_per_key when group by constant
--echo #
create table t1 (a date not null,unique (a)) engine=innodb;
select distinct a from t1 group by 'a';
insert into t1 values("2001-02-02"),("2001-02-03");
select distinct a from t1 group by 'a';
drop table t1;

12
sql/opt_range.cc
View File

@ -13105,7 +13105,17 @@ void cost_group_min_max(TABLE* table, KEY *index_info, uint used_key_parts,
num_blocks= (ha_rows)(table_records / keys_per_block) + 1;
/* Compute the number of keys in a group. */
keys_per_group= (ha_rows) index_info->actual_rec_per_key(group_key_parts - 1);
if (!group_key_parts)
{
/* Summary over the whole table */
keys_per_group= table_records;
}
else
{
keys_per_group= (ha_rows) index_info->actual_rec_per_key(group_key_parts -
1);
}
if (keys_per_group == 0) /* If there is no statistics try to guess */
/* each group contains 10% of all records */
keys_per_group= (table_records / 10) + 1;