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Fixed LP bug #904345.

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The MIN/MAX optimizer code from the function opt_sum_query erroneously
did not take into account conjunctive conditions that did not depend on
any table, yet were not identified as constant items. These could be
items containing rand() or PS/SP parameters. These items are supposed
to be evaluated at the execution phase. That's why if such conditions
can be extracted from the WHERE condition the MIN/MAX optimization is
not applied as currently it is always done at the optimization phase.

(In 5.3 expensive subqueries are also evaluated only at the execution
phase. So, if a constant condition with such subquery can be extracted
from the WHERE clause the MIN/MAX optimization should not be applied 
in 5.3.)

IF an IN/ALL/SOME predicate with a constant left part is transformed
into an EXISTS subquery the resulting subquery should not be considered
uncacheable if the right part of the predicate is not uncacheable.

Backported the function dbug_print_item() from 5.3. The function is used
only for debugging.
This commit is contained in:
Igor Babaev
2011-12-27 13:19:13 -08:00
parent a22ab047e5
commit c9259f166b
12 changed files with 123 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
mysql-test/r/func_group.result
View File

@@ -1767,4 +1767,42 @@ MAX(a)
10
drop table t1;
#
End of 5.1 tests
# Bug #904345: MIN/MAX optimization with constant FALSE condition
#
CREATE TABLE t1 (a int NOT NULL, KEY(a));
INSERT INTO t1 VALUES (10), (8), (11), (7), (15), (12), (9);
CREATE TABLE t2 (a int, b int);
INSERT INTO t2 VALUES
(8,2), (6,9), (8,4), (5,3), (9,1);
EXPLAIN EXTENDED
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT 3,4) AND a<10;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
Warnings:
Note 1003 select max(`test`.`t1`.`a`) AS `MAX(a)` from `test`.`t1` where 0
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT 3,4) AND a<10;
MAX(a)
NULL
EXPLAIN EXTENDED
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT a,b FROM t2 WHERE b<5) and a<10;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 100.00 Using where
Warnings:
Note 1003 select max(`test`.`t1`.`a`) AS `MAX(a)` from `test`.`t1` where 0
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT a,b FROM t2 WHERE b<5) and a<10;
MAX(a)
NULL
EXPLAIN EXTENDED
SELECT MAX(a) FROM t1 WHERE RAND()*0<>0 AND a<10;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 range a a 4 NULL 4 100.00 Using where; Using index
Warnings:
Note 1003 select max(`test`.`t1`.`a`) AS `MAX(a)` from `test`.`t1` where (((rand() * 0) <> 0) and (`test`.`t1`.`a` < 10))
SELECT MAX(a) FROM t1 WHERE RAND()*0<>0 AND a<10;
MAX(a)
NULL
DROP TABLE t1,t2;
#
End of 5.2 tests

6
mysql-test/r/ps_11bugs.result
View File

@@ -120,9 +120,9 @@ create table t1 (a int primary key);
insert into t1 values (1);
explain select * from t1 where 3 in (select (1+1) union select 1);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
3 UNION NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
select * from t1 where 3 in (select (1+1) union select 1);
a

8
mysql-test/r/select.result
View File

@@ -2778,10 +2778,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
explain select max(key1) from t1 where key1 <= 0.6158 and rand() + 0.5 >= 0.5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
1 SIMPLE t1 index key1 key1 5 NULL 4 Using where; Using index
explain select min(key1) from t1 where key1 >= 0.3762 and rand() + 0.5 >= 0.5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
1 SIMPLE t1 range key1 key1 5 NULL 3 Using where; Using index
select max(key1) from t1 where key1 <= 0.6158;
max(key1)
0.615800023078918
@@ -2800,10 +2800,10 @@ max(key1) min(key2)
0.615800023078918 1.37619996070862
select max(key1) from t1 where key1 <= 0.6158 and rand() + 0.5 >= 0.5;
max(key1)
0.615800023078918
0.384499996900558
select min(key1) from t1 where key1 >= 0.3762 and rand() + 0.5 >= 0.5;
min(key1)
0.376199990510941
0.384499996900558
DROP TABLE t1,t2;
CREATE TABLE t1 (i BIGINT UNSIGNED NOT NULL);
INSERT INTO t1 VALUES (10);

8
mysql-test/r/select_pkeycache.result
View File

@@ -2778,10 +2778,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
explain select max(key1) from t1 where key1 <= 0.6158 and rand() + 0.5 >= 0.5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
1 SIMPLE t1 index key1 key1 5 NULL 4 Using where; Using index
explain select min(key1) from t1 where key1 >= 0.3762 and rand() + 0.5 >= 0.5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
1 SIMPLE t1 range key1 key1 5 NULL 3 Using where; Using index
select max(key1) from t1 where key1 <= 0.6158;
max(key1)
0.615800023078918
@@ -2800,10 +2800,10 @@ max(key1) min(key2)
0.615800023078918 1.37619996070862
select max(key1) from t1 where key1 <= 0.6158 and rand() + 0.5 >= 0.5;
max(key1)
0.615800023078918
0.384499996900558
select min(key1) from t1 where key1 >= 0.3762 and rand() + 0.5 >= 0.5;
min(key1)
0.376199990510941
0.384499996900558
DROP TABLE t1,t2;
CREATE TABLE t1 (i BIGINT UNSIGNED NOT NULL);
INSERT INTO t1 VALUES (10);

14
mysql-test/r/subselect.result
View File

@@ -1302,7 +1302,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL No tables used
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
Warnings:
Note 1003 select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
INSERT INTO t1 (pseudo) VALUES ('test1');
@@ -1312,7 +1312,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL No tables used
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
Warnings:
Note 1003 select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
drop table t1;
@@ -4476,15 +4476,15 @@ INSERT INTO t1 VALUES (1),(2);
EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 GROUP BY a);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
2 SUBQUERY t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
Warnings:
Note 1003 select 1 AS `1` from `test`.`t1` where <in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having 1))
Note 1003 select 1 AS `1` from `test`.`t1` where 1
EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 WHERE a > 3 GROUP BY a);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 2 100.00 Using where; Using temporary; Using filesort
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY t1 ALL NULL NULL NULL NULL 2 100.00 Using where; Using temporary; Using filesort
Warnings:
Note 1003 select 1 AS `1` from `test`.`t1` where <in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having 1))
Note 1003 select 1 AS `1` from `test`.`t1` where 0
DROP TABLE t1;
#
# Bug#45061: Incorrectly market field caused wrong result.

6
mysql-test/suite/pbxt/r/ps_11bugs.result
View File

@@ -120,9 +120,9 @@ create table t1 (a int primary key);
insert into t1 values (1);
explain select * from t1 where 3 in (select (1+1) union select 1);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
3 UNION NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
select * from t1 where 3 in (select (1+1) union select 1);
a

8
mysql-test/suite/pbxt/r/select.result
View File

@@ -2786,10 +2786,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
explain select max(key1) from t1 where key1 <= 0.6158 and rand() + 0.5 >= 0.5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
1 SIMPLE t1 index key1 key1 5 NULL 4 Using where; Using index
explain select min(key1) from t1 where key1 >= 0.3762 and rand() + 0.5 >= 0.5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
1 SIMPLE t1 index key1 key1 5 NULL 4 Using where; Using index
select max(key1) from t1 where key1 <= 0.6158;
max(key1)
0.615800023078918
@@ -2808,10 +2808,10 @@ max(key1) min(key2)
0.615800023078918 1.37619996070862
select max(key1) from t1 where key1 <= 0.6158 and rand() + 0.5 >= 0.5;
max(key1)
0.615800023078918
0.384499996900558
select min(key1) from t1 where key1 >= 0.3762 and rand() + 0.5 >= 0.5;
min(key1)
0.376199990510941
0.384499996900558
DROP TABLE t1,t2;
CREATE TABLE t1 (i BIGINT UNSIGNED NOT NULL);
INSERT INTO t1 VALUES (10);

4
mysql-test/suite/pbxt/r/subselect.result
View File

@@ -1177,7 +1177,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL No tables used
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
Warnings:
Note 1003 select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
INSERT INTO t1 (pseudo) VALUES ('test1');
@@ -1187,7 +1187,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL No tables used
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
Warnings:
Note 1003 select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
drop table t1;

27
mysql-test/t/func_group.test
View File

@@ -1150,4 +1150,29 @@ SELECT MAX(a) FROM t1 WHERE a NOT BETWEEN 3 AND 9;
drop table t1;
--echo #
--echo End of 5.1 tests
--echo # Bug #904345: MIN/MAX optimization with constant FALSE condition
--echo #
CREATE TABLE t1 (a int NOT NULL, KEY(a));
INSERT INTO t1 VALUES (10), (8), (11), (7), (15), (12), (9);
CREATE TABLE t2 (a int, b int);
INSERT INTO t2 VALUES
(8,2), (6,9), (8,4), (5,3), (9,1);
EXPLAIN EXTENDED
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT 3,4) AND a<10;
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT 3,4) AND a<10;
EXPLAIN EXTENDED
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT a,b FROM t2 WHERE b<5) and a<10;
SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT a,b FROM t2 WHERE b<5) and a<10;
EXPLAIN EXTENDED
SELECT MAX(a) FROM t1 WHERE RAND()*0<>0 AND a<10;
SELECT MAX(a) FROM t1 WHERE RAND()*0<>0 AND a<10;
DROP TABLE t1,t2;
--echo #
--echo End of 5.2 tests

21
sql/item.cc
View File

@@ -7915,6 +7915,27 @@ void view_error_processor(THD *thd, void *data)
((TABLE_LIST *)data)->hide_view_error(thd);
}
#ifndef DBUG_OFF
/* Debugger help function */
static char dbug_item_print_buf[256];
const char *dbug_print_item(Item *item)
{
char *buf= dbug_item_print_buf;
String str(buf, sizeof(dbug_item_print_buf), &my_charset_bin);
str.length(0);
if (!item)
return "(Item*)NULL";
item->print(&str ,QT_ORDINARY);
if (str.c_ptr() == buf)
return buf;
else
return "Couldn't fit into buffer";
}
#endif /*DBUG_OFF*/
/*****************************************************************************
** Instantiate templates
*****************************************************************************/

13
sql/item_subselect.cc
View File

@@ -1117,8 +1117,8 @@ Item_in_subselect::single_value_transformer(JOIN *join,
(Item**)optimizer->get_cache(),
(char *)"<no matter>",
(char *)in_left_expr_name);
master_unit->uncacheable|= UNCACHEABLE_DEPENDENT;
if (!left_expr->const_item())
master_unit->uncacheable|= UNCACHEABLE_DEPENDENT;
}
if (!abort_on_null && left_expr->maybe_null && !pushed_cond_guards)
{
@@ -1127,7 +1127,8 @@ Item_in_subselect::single_value_transformer(JOIN *join,
pushed_cond_guards[0]= TRUE;
}
select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
if (!left_expr->const_item())
select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
if (join->having || select_lex->with_sum_func ||
select_lex->group_list.elements)
{
@@ -1338,7 +1339,8 @@ Item_in_subselect::row_value_transformer(JOIN *join)
optimizer->keep_top_level_cache();
thd->lex->current_select= current;
master_unit->uncacheable|= UNCACHEABLE_DEPENDENT;
if (!left_expr->const_item())
master_unit->uncacheable|= UNCACHEABLE_DEPENDENT;
if (!abort_on_null && left_expr->maybe_null && !pushed_cond_guards)
{
@@ -1350,7 +1352,8 @@ Item_in_subselect::row_value_transformer(JOIN *join)
}
}
select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
if (!left_expr->const_item())
select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
if (is_having_used)
{
/*

3
sql/opt_sum.cc
View File

@@ -608,7 +608,8 @@ static bool matching_cond(bool max_fl, TABLE_REF *ref, KEY *keyinfo,
if (!cond)
DBUG_RETURN(TRUE);
Field *field= field_part->field;
if (!(cond->used_tables() & field->table->map))
if (!(cond->used_tables() & field->table->map) &&
test(cond->used_tables() & ~PSEUDO_TABLE_BITS))
{
/* Condition doesn't restrict the used table */
DBUG_RETURN(TRUE);