Commit 45cad70f authored by unknown's avatar unknown
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Bug #22781: SQL_BIG_RESULT fails to influence sort plan 

 Currently SQL_BIG_RESULT is checked only at compile time.
 However, additional optimizations may take place after
 this check that change the sort method from 'filesort'
 to sorting via index. As a result the actual plan
 executed is not the one specified by the SQL_BIG_RESULT
 hint. Similarly, there is no such test when executing
 EXPLAIN, resulting in incorrect output.
 The patch corrects the problem by testing for
 SQL_BIG_RESULT both during the explain and execution
 phases.


mysql-test/r/bdb.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - updated sql_big_result testcase
mysql-test/r/group_by.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with MyISAM
mysql-test/r/innodb.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - updated sql_big_result testcase
mysql-test/r/innodb_mysql.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with InnoDB
mysql-test/r/myisam.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - updated sql_big_result testcase
mysql-test/t/group_by.test:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with MyISAM
mysql-test/t/innodb_mysql.test:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with InnoDB
sql/sql_select.cc:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - When SQL_BIG_RESULT is specified, disable the optimization performed
  at execution/explain time that decides to use an index instead
  of filesort.
parent 04bf9cc7

mysql-test/r/group_by.result

+65 −2
Original line number Diff line number Diff line
@@ -303,10 +303,10 @@ spid sum(userid) 
1	1

explain select sql_big_result score,count(*) from t1 group by score desc;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	NULL	score	3	NULL	8	Using index

1	SIMPLE	t1	index	NULL	score	3	NULL	8	Using index; Using filesort

explain select sql_big_result score,count(*) from t1 group by score desc order by null;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	NULL	score	3	NULL	8	Using index

1	SIMPLE	t1	index	NULL	score	3	NULL	8	Using index; Using filesort

select sql_big_result score,count(*) from t1 group by score desc;

score	count(*)

3	5
@@ -821,3 +821,66 @@ a b real_b 
68	France	France

DROP VIEW v1;

DROP TABLE t1,t2;

CREATE TABLE t1 (a INT PRIMARY KEY, b INT, key (b));

INSERT INTO t1 VALUES (1,      1);

INSERT INTO t1 SELECT  a + 1 , MOD(a + 1 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 2 , MOD(a + 2 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 4 , MOD(a + 4 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 8 , MOD(a + 8 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 16, MOD(a + 16, 20) FROM t1;

INSERT INTO t1 SELECT  a + 32, MOD(a + 32, 20) FROM t1;

INSERT INTO t1 SELECT  a + 64, MOD(a + 64, 20) FROM t1;

SELECT MIN(b), MAX(b) from t1;

MIN(b)	MAX(b)

0	19

EXPLAIN SELECT b, sum(1) FROM t1 GROUP BY b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	NULL	b	5	NULL	128	Using index

EXPLAIN SELECT SQL_BIG_RESULT b, sum(1) FROM t1 GROUP BY b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	NULL	b	5	NULL	128	Using index; Using filesort

SELECT b, sum(1) FROM t1 GROUP BY b;

b	sum(1)

0	6

1	7

2	7

3	7

4	7

5	7

6	7

7	7

8	7

9	6

10	6

11	6

12	6

13	6

14	6

15	6

16	6

17	6

18	6

19	6

SELECT SQL_BIG_RESULT b, sum(1) FROM t1 GROUP BY b;

b	sum(1)

0	6

1	7

2	7

3	7

4	7

5	7

6	7

7	7

8	7

9	6

10	6

11	6

12	6

13	6

14	6

15	6

16	6

17	6

18	6

19	6

DROP TABLE t1;

mysql-test/r/innodb_mysql.result

+16 −0
Original line number Diff line number Diff line
@@ -337,3 +337,19 @@ id select_type table type possible_keys key key_len ref rows Extra 
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 (a INT PRIMARY KEY, b INT, c FLOAT, KEY b(b)) ENGINE = INNODB;

INSERT INTO t1 VALUES (    1 , 1              , 1);

INSERT INTO t1 SELECT  a + 1 , MOD(a + 1 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 2 , MOD(a + 2 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 4 , MOD(a + 4 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 8 , MOD(a + 8 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 16, MOD(a + 16, 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 32, MOD(a + 32, 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 64, MOD(a + 64, 20), 1 FROM t1;

EXPLAIN SELECT b, SUM(c) FROM t1 GROUP BY b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	NULL	b	5	NULL	128	

EXPLAIN SELECT SQL_BIG_RESULT b, SUM(c) FROM t1 GROUP BY b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	128	Using filesort

DROP TABLE t1;

mysql-test/t/group_by.test

+22 −0
Original line number Diff line number Diff line
@@ -655,3 +655,25 @@ where t2.b=v1.a GROUP BY t2.b; 


DROP VIEW v1;

DROP TABLE t1,t2;



#

# Bug#22781: SQL_BIG_RESULT fails to influence sort plan

#

CREATE TABLE t1 (a INT PRIMARY KEY, b INT, key (b));



INSERT INTO t1 VALUES (1,      1);

INSERT INTO t1 SELECT  a + 1 , MOD(a + 1 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 2 , MOD(a + 2 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 4 , MOD(a + 4 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 8 , MOD(a + 8 , 20) FROM t1;

INSERT INTO t1 SELECT  a + 16, MOD(a + 16, 20) FROM t1;

INSERT INTO t1 SELECT  a + 32, MOD(a + 32, 20) FROM t1;

INSERT INTO t1 SELECT  a + 64, MOD(a + 64, 20) FROM t1;



SELECT MIN(b), MAX(b) from t1;



EXPLAIN SELECT b, sum(1) FROM t1 GROUP BY b;

EXPLAIN SELECT SQL_BIG_RESULT b, sum(1) FROM t1 GROUP BY b;

SELECT b, sum(1) FROM t1 GROUP BY b;

SELECT SQL_BIG_RESULT b, sum(1) FROM t1 GROUP BY b;

DROP TABLE t1;

mysql-test/t/innodb_mysql.test

+18 −0
Original line number Diff line number Diff line
@@ -302,3 +302,21 @@ SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id 
  WHERE t1.name LIKE 'A%' OR FALSE;



DROP TABLE t1,t2;



#

# Bug#22781: SQL_BIG_RESULT fails to influence sort plan

#

CREATE TABLE t1 (a INT PRIMARY KEY, b INT, c FLOAT, KEY b(b)) ENGINE = INNODB;



INSERT INTO t1 VALUES (    1 , 1              , 1);

INSERT INTO t1 SELECT  a + 1 , MOD(a + 1 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 2 , MOD(a + 2 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 4 , MOD(a + 4 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 8 , MOD(a + 8 , 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 16, MOD(a + 16, 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 32, MOD(a + 32, 20), 1 FROM t1;

INSERT INTO t1 SELECT  a + 64, MOD(a + 64, 20), 1 FROM t1;



EXPLAIN SELECT b, SUM(c) FROM t1 GROUP BY b;

EXPLAIN SELECT SQL_BIG_RESULT b, SUM(c) FROM t1 GROUP BY b;

DROP TABLE t1;

sql/sql_select.cc

+10 −3
Original line number Diff line number Diff line
@@ -1400,6 +1400,7 @@ JOIN::exec() 
      skip_sort_order= 0;

    }

    if (order && 

        (order != group_list || !(select_options & SELECT_BIG_RESULT)) &&

	(const_tables == tables ||

 	 ((simple_order || skip_sort_order) &&

	  test_if_skip_sort_order(&join_tab[const_tables], order,
@@ -11995,11 +11996,17 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order, 
  table=  tab->table;

  select= tab->select;



  if (test_if_skip_sort_order(tab,order,select_limit,0))

  /*

    When there is SQL_BIG_RESULT do not sort using index for GROUP BY,

    and thus force sorting on disk.

  */

  if ((order != join->group_list || 

       !(join->select_options & SELECT_BIG_RESULT)) &&

      test_if_skip_sort_order(tab,order,select_limit,0))

    DBUG_RETURN(0);

  if (!(sortorder=make_unireg_sortorder(order,&length)))

    goto err;				/* purecov: inspected */

  /* It's not fatal if the following alloc fails */



  table->sort.io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),

                                             MYF(MY_WME | MY_ZEROFILL));

  table->status=0;				// May be wrong if quick_select

mysql-test/r/bdb.result

+36 −36

File changed.

Contains only whitespace changes.

mysql-test/r/innodb.result

+8 −8

File changed.

Contains only whitespace changes.

mysql-test/r/myisam.result

+8 −8

File changed.

Contains only whitespace changes.