config root man

#
# Bug#18167648: WRONG RESULTS WITH PARTITIONING, INDEX_MERGE AND NO PK
#
CREATE TABLE t1 (
a smallint,
b smallint,
c smallint,
KEY  a (a),
KEY  b (b)
) ENGINE = MyISAM
PARTITION BY HASH (c) PARTITIONS 3;
Warnings:
Warning	1287	The partition engine, used by table 'test.t1', is deprecated and will be removed in a future release. Please use native partitioning instead.
CREATE TABLE t2 (a tinyint) ENGINE = MyISAM;
INSERT INTO t2 VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),(13),
(14),(15),(16);
SET SESSION optimizer_switch="index_merge=on";
SET SESSION optimizer_switch="index_merge_intersection=on";
SET SESSION optimizer_switch="index_merge_union=off";
SET SESSION optimizer_switch="index_merge_sort_union=off";
INSERT INTO t1 VALUES (1,1,0), (1,1,0), (2,1,0), (2,2,1), (1,1,1), (2,2,4);
Warnings:
Warning	1287	The partition engine, used by table 'test.t1', is deprecated and will be removed in a future release. Please use native partitioning instead.
# Add some rows to make the index_merge_intersect possible
INSERT INTO t1 SELECT 1,1,0 FROM t2 A, t2 B;
INSERT INTO t1 SELECT 1,1,1 FROM t2 A, t2 B;
INSERT INTO t1 SELECT 1,1,2 FROM t2 A, t2 B LIMIT 68;
SELECT COUNT(*) FROM t1;
COUNT(*)
586
ANALYZE TABLE t1;
Table	Op	Msg_type	Msg_text
test.t1	analyze	status	OK
test.t1	analyze	warning	The partition engine, used by table 'test.t1', is deprecated and will be removed in a future release. Please use native partitioning instead.
EXPLAIN SELECT a,b,c FROM t1 WHERE b = 2 AND a = 2;
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t1	p0,p1,p2	index_merge	a,b	b,a	3,3	NULL	1	100.00	Using intersect(b,a); Using where
Warnings:
Warning	1287	The partition engine, used by table 'test.t1', is deprecated and will be removed in a future release. Please use native partitioning instead.
Note	1003	/* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`a` = 2) and (`test`.`t1`.`b` = 2))
# Before fix:
# (p0 - partition 0, R3 - 3rd record in that partition = offset)
# Make 'a' read p0-R3, p1-R1, p1-R3
# Make 'b' read p1-R1, p1-R3
# 'b' will skip p1-R1 since R3 is bigger than R1.
SELECT a,b,c FROM t1 WHERE b = 2 AND a = 2;
a	b	c
2	2	1
2	2	4
SET @old_opt_switch = @@session.optimizer_switch;
SET SESSION optimizer_switch="index_merge_intersection=off";
# Without index_merge_intersection
SELECT a,b,c FROM t1 WHERE b = 2 AND a = 2;
a	b	c
2	2	1
2	2	4
EXPLAIN SELECT a,b,c FROM t1 WHERE b = 2 AND a = 2;
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t1	p0,p1,p2	ref	a,b	b	3	const	2	2.50	Using where
Warnings:
Note	1003	/* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`a` = 2) and (`test`.`t1`.`b` = 2))
SET SESSION optimizer_switch="index_merge_union=on";
EXPLAIN SELECT a,b,c FROM t1 WHERE (b = 2 OR a = 2) AND  c > 0 AND c < 100;
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t1	p0,p1,p2	index_merge	a,b	b,a	3,3	NULL	5	11.11	Using union(b,a); Using where
Warnings:
Note	1003	/* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`b` = 2) or (`test`.`t1`.`a` = 2)) and (`test`.`t1`.`c` > 0) and (`test`.`t1`.`c` < 100))
SELECT a,b,c FROM t1 WHERE (b = 2 OR a = 2) AND  c > 0 AND c < 100;
a	b	c
2	2	1
2	2	4
SET SESSION optimizer_switch="index_merge_union=off";
SELECT a,b,c FROM t1 WHERE (b = 2 OR a = 2) AND  c > 0 AND c < 100;
a	b	c
2	2	1
2	2	4
EXPLAIN SELECT a,b,c FROM t1 WHERE (b = 2 OR a = 2) AND  c > 0 AND c < 100;
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t1	p0,p1,p2	ALL	a,b	NULL	NULL	NULL	586	6.29	Using where
Warnings:
Note	1003	/* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`b` = 2) or (`test`.`t1`.`a` = 2)) and (`test`.`t1`.`c` > 0) and (`test`.`t1`.`c` < 100))
SET SESSION optimizer_switch="index_merge_sort_union=on";
EXPLAIN SELECT a,b,c FROM t1 WHERE (b >= 2 OR a >= 2) AND  c > 0 AND c < 100;
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t1	p0,p1,p2	index_merge	a,b	b,a	3,3	NULL	10	11.11	Using sort_union(b,a); Using where
Warnings:
Note	1003	/* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`b` >= 2) or (`test`.`t1`.`a` >= 2)) and (`test`.`t1`.`c` > 0) and (`test`.`t1`.`c` < 100))
# Not affected, added for completeness...
SELECT a,b,c FROM t1 WHERE (b >= 2 OR a >= 2) AND  c > 0 AND c < 100;
a	b	c
2	2	1
2	2	4
SET SESSION optimizer_switch="index_merge_sort_union=off";
SELECT a,b,c FROM t1 WHERE (b >= 2 OR a >= 2) AND  c > 0 AND c < 100;
a	b	c
2	2	1
2	2	4
EXPLAIN SELECT a,b,c FROM t1 WHERE (b >= 2 OR a >= 2) AND  c > 0 AND c < 100;
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t1	p0,p1,p2	ALL	a,b	NULL	NULL	NULL	586	6.17	Using where
Warnings:
Note	1003	/* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where (((`test`.`t1`.`b` >= 2) or (`test`.`t1`.`a` >= 2)) and (`test`.`t1`.`c` > 0) and (`test`.`t1`.`c` < 100))
SET @@session.optimizer_switch = @old_opt_switch;
DROP TABLE t1, t2;