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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
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Inline Side-by-side
Showing with 183 additions and 57 deletions
mysql-test/r/group_by.result
View file @ 45cad70f
......@@ -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
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2 7
3 7
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5 7
6 7
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12 6
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SELECT SQL_BIG_RESULT b, sum(1) FROM t1 GROUP BY b;
b sum(1)
0 6
1 7
2 7
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5 7
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7 7
8 7
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DROP TABLE t1;
mysql-test/r/innodb_mysql.result
View file @ 45cad70f
......@@ -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
View file @ 45cad70f
......@@ -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
View file @ 45cad70f
......@@ -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
View file @ 45cad70f
......@@ -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
......
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