Commit c21dbf27 authored by sergefp@mysql.com's avatar sergefp@mysql.com
Browse files

BUG#35850 "Performance regression in 5.1.23/5.1.24" 

- Disable the "prefer full scan on clustered primary key over full scan
  of any secondary key" rule introduced by BUG#35850.
- Update test results accordingly 
(bk trigger: file this for BUG#35850)
parent f315e663

mysql-test/r/innodb.result

+15 −15
Original line number Diff line number Diff line
@@ -925,7 +925,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	SIMPLE	t1	index	NULL	b	4	NULL	#	Using index

explain select a,b from t1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	#	

1	SIMPLE	t1	index	NULL	b	4	NULL	#	Using index

explain select a,b,c from t1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	#
@@ -1166,14 +1166,14 @@ UPDATE t1 set a=a+100 where b between 2 and 3 and a < 1000; 
SELECT * from t1;

a	b

1	1

102	2

103	3

4	4

5	5

6	6

7	7

8	8

9	9

102	2

103	3

drop table t1;

CREATE TABLE t1 (a int not null primary key, b int not null, key (b)) engine=innodb;

CREATE TABLE t2 (a int not null primary key, b int not null, key (b)) engine=innodb;
@@ -1197,6 +1197,7 @@ a b 
update t1,t2 set t1.a=t1.a+100 where t1.a=101;

select * from t1;

a	b

201	1

102	2

103	3

104	4
@@ -1208,11 +1209,10 @@ a b 
110	10

111	11

112	12

201	1

update t1,t2 set t1.b=t1.b+10 where t1.b=2;

select * from t1;

a	b

102	12

201	1

103	3

104	4

105	5
@@ -1222,34 +1222,34 @@ a b 
109	9

110	10

111	11

102	12

112	12

201	1

update t1,t2 set t1.b=t1.b+2,t2.b=t1.b+10 where t1.b between 3 and 5 and t1.a=t2.a+100;

select * from t1;

a	b

102	12

201	1

103	5

104	6

105	7

106	6

105	7

107	7

108	8

109	9

110	10

111	11

102	12

112	12

201	1

select * from t2;

a	b

1	1

2	2

3	13

4	14

5	15

6	6

7	7

8	8

9	9

3	13

4	14

5	15

drop table t1,t2;

CREATE TABLE t2 (   NEXT_T         BIGINT NOT NULL PRIMARY KEY) ENGINE=MyISAM;

CREATE TABLE t1 (  B_ID           INTEGER NOT NULL PRIMARY KEY) ENGINE=InnoDB;
@@ -1300,11 +1300,11 @@ insert into t1 (id) values (null),(null),(null),(null),(null); 
update t1 set fk=69 where fk is null order by id limit 1;

SELECT * from t1;

id	fk

1	69

2	NULL

3	NULL

4	NULL

5	NULL

1	69

drop table t1;

create table t1 (a int not null, b int not null, key (a));

insert into t1 values (1,1),(1,2),(1,3),(3,1),(3,2),(3,3),(3,1),(3,2),(3,3),(2,1),(2,2),(2,3);
@@ -2438,8 +2438,8 @@ insert into t1 (b) values (1); 
replace into t1 (b) values (2), (1), (3);

select * from t1;

a	b

2	2

3	1

2	2

4	3

truncate table t1;

insert into t1 (b) values (1);
@@ -2448,8 +2448,8 @@ replace into t1 (b) values (1); 
replace into t1 (b) values (3);

select * from t1;

a	b

2	2

3	1

2	2

4	3

drop table t1;

create table t1 (rowid int not null auto_increment, val int not null,primary

mysql-test/r/innodb_mysql.result

+18 −8
Original line number Diff line number Diff line
@@ -355,13 +355,13 @@ EXPLAIN 
SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id

WHERE t1.name LIKE 'A%';

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	PRIMARY,name	PRIMARY	4	NULL	3	Using where

1	SIMPLE	t1	index	PRIMARY,name	name	23	NULL	3	Using where; Using index

1	SIMPLE	t2	ref	fkey	fkey	5	test.t1.id	1	Using where; Using index

EXPLAIN

SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id

WHERE t1.name LIKE 'A%' OR FALSE;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t2	index	NULL	PRIMARY	4	NULL	5	

1	SIMPLE	t2	index	NULL	fkey	5	NULL	5	Using index

1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.fkey	1	Using where

DROP TABLE t1,t2;

CREATE TABLE t1 (
@@ -1268,11 +1268,11 @@ select_type SIMPLE 
table	t1

type	index

possible_keys	NULL

key	PRIMARY

key_len	4

key	b

key_len	5

ref	NULL

rows	3

Extra	Using filesort

Extra	Using index; Using filesort

SELECT * FROM t1 ORDER BY b ASC, a DESC;

a	b

1	1
@@ -1284,11 +1284,11 @@ select_type SIMPLE 
table	t1

type	index

possible_keys	NULL

key	PRIMARY

key_len	4

key	b

key_len	5

ref	NULL

rows	3

Extra	Using filesort

Extra	Using index; Using filesort

SELECT * FROM t1 ORDER BY b DESC, a ASC;

a	b

2	2
@@ -1654,3 +1654,13 @@ ALTER TABLE t1 CHANGE id id2 INT; 
DROP TABLE t2;

DROP TABLE t1;

End of 5.1 tests

drop table if exists t1, t2, t3;

create table t1(a int);

insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

create table t2 (a int, b int, pk int, key(a,b), primary key(pk)) engine=innodb;

insert into t2 select @a:=A.a+10*(B.a + 10*C.a),@a, @a from t1 A, t1 B, t1 C;

this must use key 'a', not PRIMARY:

explain select a from t2 where a=b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t2	index	NULL	a	10	NULL	#	Using where; Using index

drop table t1, t2;

mysql-test/r/join_outer_innodb.result

+2 −2
Original line number Diff line number Diff line
@@ -8,12 +8,12 @@ EXPLAIN 
SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id 

WHERE t1.name LIKE 'A%';

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	PRIMARY,name	PRIMARY	4	NULL	3	Using where

1	SIMPLE	t1	index	PRIMARY,name	name	23	NULL	3	Using where; Using index

1	SIMPLE	t2	ref	fkey	fkey	5	test.t1.id	1	Using where; Using index

EXPLAIN

SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id 

WHERE t1.name LIKE 'A%' OR FALSE;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t2	index	NULL	PRIMARY	4	NULL	5	

1	SIMPLE	t2	index	NULL	fkey	5	NULL	5	Using index

1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.fkey	1	Using where

DROP TABLE t1,t2;

mysql-test/t/innodb_mysql.test

+16 −0
Original line number Diff line number Diff line
@@ -13,3 +13,19 @@ let $test_foreign_keys= 1; 
set global innodb_support_xa=default;

set session innodb_support_xa=default;

--source include/mix1.inc



--disable_warnings

drop table if exists t1, t2, t3;

--enable_warnings

#

# BUG#35850: Performance regression in 5.1.23/5.1.24

#

create table t1(a int);

insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

create table t2 (a int, b int, pk int, key(a,b), primary key(pk)) engine=innodb;

insert into t2 select @a:=A.a+10*(B.a + 10*C.a),@a, @a from t1 A, t1 B, t1 C;

--echo this must use key 'a', not PRIMARY:

--replace_column 9 #

explain select a from t2 where a=b;

drop table t1, t2;

sql/sql_select.cc

+6 −3
Original line number Diff line number Diff line
@@ -6506,13 +6506,16 @@ make_join_readinfo(JOIN *join, ulonglong options) 
		   !(tab->select && tab->select->quick))

	  {					// Only read index tree

	    /*

	      See bug #26447: "Using the clustered index for a table scan

	      is always faster than using a secondary index".

	    */

            It has turned out that the below change, while speeding things

            up for disk-bound loads, slows them down for cases when the data

            is in disk cache (see BUG#35850):

	    //  See bug #26447: "Using the clustered index for a table scan

	    //  is always faster than using a secondary index".

            if (table->s->primary_key != MAX_KEY &&

                table->file->primary_key_is_clustered())

              tab->index= table->s->primary_key;

            else

	    */

              tab->index=find_shortest_key(table, & table->covering_keys);

	    tab->read_first_record= join_read_first;

	    tab->type=JT_NEXT;		// Read with index_first / index_next