mariadb/mysql-test/t/func_group_innodb.test
Chaithra Gopalareddy 25f82f8a26 Bug#12713907:STRANGE OPTIMIZE & WRONG RESULT UNDER
ORDER BY COUNT(*) LIMIT.

PROBLEM:
With respect to problem in the bug description, we
exhibit different behaviors for the two tables
presented, because innodb statistics (rec_per_key
in this case) are updated for the first table
and not so for the second one. As a result the
query plan gets changed in test_if_skip_sort_order
to use 'index' scan. Hence the difference in the
explain output. (NOTE: We can reproduce the problem
with first table by reducing the number of tuples
and changing the table structure)

The varied output w.r.t the query on the second table
is because of the result in the query plan change.
When a query plan is changed to use 'index' scan,
after the call to test_if_skip_sort_order, we set
keyread to TRUE immedietly. If for some reason
we drop this index scan for a filesort later on,
we fetch only the keys not the entire tuple.
As a result we would see junk values in the result set.

Following is the code flow:

Call test_if_skip_sort_order
-Choose an index to give sorted output
-If this is a covering index, set_keyread to TRUE
-Set the scan to INDEX scan

Call test_if_skip_sort_order second time
-Index is not chosen (note that we do not pass the
actual limit value second time. Hence we do not choose
index scan second time which in itself is a bug fixed
in 5.6 with WL#5558)
-goto filesort

Call filesort
-Create quick range on a different index
-Since keyread is set to TRUE, we fetch only the columns of
the index
-results in the required columns are not fetched

FIX:
Remove the call to set_keyread(TRUE) from
test_if_skip_sort_order. The access function which is
'join_read_first' or 'join_read_last' calls set_keyread anyways.


mysql-test/r/func_group_innodb.result:
  Added test result for Bug#12713907
mysql-test/t/func_group_innodb.test:
  Added test case for Bug#12713907
sql/sql_select.cc:
  Remove the call to set_keyread as we do it from access
  functions 'join_read_first' and 'join_read_last'
2012-04-18 11:25:01 +05:30

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Text

#
# Test of group functions that depend on innodb
#
--source include/have_innodb.inc
--disable_warnings
create table t1 (USR_ID integer not null, MAX_REQ integer not null, constraint PK_SEA_USER primary key (USR_ID)) engine=InnoDB;
--enable_warnings
insert into t1 values (1, 3);
select count(*) + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ from t1 group by MAX_REQ;
select Case When Count(*) < MAX_REQ Then 1 Else 0 End from t1 where t1.USR_ID = 1 group by MAX_REQ;
drop table t1;
#
# Bug #12882 min/max inconsistent on empty table
#
--disable_warnings
create table t1m (a int) engine=myisam;
create table t1i (a int) engine=innodb;
create table t2m (a int) engine=myisam;
create table t2i (a int) engine=innodb;
--enable_warnings
insert into t2m values (5);
insert into t2i values (5);
# test with MyISAM
select min(a) from t1m;
select min(7) from t1m;
select min(7) from DUAL;
explain select min(7) from t2m join t1m;
select min(7) from t2m join t1m;
select max(a) from t1m;
select max(7) from t1m;
select max(7) from DUAL;
explain select max(7) from t2m join t1m;
select max(7) from t2m join t1m;
select 1, min(a) from t1m where a=99;
select 1, min(a) from t1m where 1=99;
select 1, min(1) from t1m where a=99;
select 1, min(1) from t1m where 1=99;
select 1, max(a) from t1m where a=99;
select 1, max(a) from t1m where 1=99;
select 1, max(1) from t1m where a=99;
select 1, max(1) from t1m where 1=99;
# test with InnoDB
select min(a) from t1i;
select min(7) from t1i;
select min(7) from DUAL;
explain select min(7) from t2i join t1i;
select min(7) from t2i join t1i;
select max(a) from t1i;
select max(7) from t1i;
select max(7) from DUAL;
explain select max(7) from t2i join t1i;
select max(7) from t2i join t1i;
select 1, min(a) from t1i where a=99;
select 1, min(a) from t1i where 1=99;
select 1, min(1) from t1i where a=99;
select 1, min(1) from t1i where 1=99;
select 1, max(a) from t1i where a=99;
select 1, max(a) from t1i where 1=99;
select 1, max(1) from t1i where a=99;
select 1, max(1) from t1i where 1=99;
# mixed MyISAM/InnoDB test
explain select count(*), min(7), max(7) from t1m, t1i;
select count(*), min(7), max(7) from t1m, t1i;
explain select count(*), min(7), max(7) from t1m, t2i;
select count(*), min(7), max(7) from t1m, t2i;
explain select count(*), min(7), max(7) from t2m, t1i;
select count(*), min(7), max(7) from t2m, t1i;
drop table t1m, t1i, t2m, t2i;
--echo #
--echo # Bug#12713907: STRANGE OPTIMIZE & WRONG RESULT UNDER ORDER BY
--echo # COUNT(*) LIMIT.
--echo #
CREATE TABLE t1 (
id BIGINT(20) ,
member_id_to INT(11) ,
r_date DATE ,
PRIMARY KEY (id,r_date),
KEY r_date_idx (r_date),
KEY t1_idx01 (member_id_to)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES
(107924526,518491,'2011-05-01'),
(107924527,518491,'2011-05-01'),
(107924528,518491,'2011-05-01'),
(107924529,518491,'2011-05-01'),
(107924530,518491,'2011-05-01'),
(107924531,518491,'2011-05-01'),
(107924532,518491,'2011-05-01'),
(107924534,518491,'2011-06-21'),
(107924535,518491,'2011-06-21'),
(107924536,518491,'2011-06-21'),
(107924537,518491,'2011-06-21'),
(107924538,518491,'2011-06-21'),
(107924542,1601319,'2011-06-21'),
(107924543,1601319,'2011-06-21'),
(107924544,1601319,'2011-06-21'),
(107924545,1601319,'2011-06-21'),
(107924546,1601319,'2011-06-21'),
(107924547,1601319,'2011-06-21'),
(107924548,1601319,'2011-06-21'),
(107924549,1601319,'2011-06-21'),
(107924550,1601319,'2011-06-21');
SELECT member_id_to, COUNT(*) FROM t1 WHERE r_date =
'2011-06-21' GROUP BY member_id_to ORDER BY 2 LIMIT 1;
DROP TABLE t1;
--echo # End of test BUG#12713907