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Fixed bug mdev-4366.

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When performing the range analysis for a conjunction the function
calculate_cond_selectivity_for_table should take in to account that
the analysis of some conjuncts may return SEL_ARG::IMPOSSIBLE.
This commit is contained in:
Igor Babaev
2013-04-04 14:11:31 -07:00
parent 50d4d1ca18
commit 4079a5dc3f
4 changed files with 102 additions and 11 deletions
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34
mysql-test/r/selectivity.result
View File

@ -751,10 +751,10 @@ set histogram_size=@save_histogram_size;
set histogram_type=@save_histogram_type;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
#
# Bug mdev-4367: join of a merged empty derived table
# Bug mdev-4367: 2-way join with an empty table
# when optimizer_use_condition_selectivity=3
#
SET optimizer_use_condition_selectivity=3;
set optimizer_use_condition_selectivity=3;
CREATE TABLE t1 (a varchar(1)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('j'),('k');
CREATE TABLE t2 (b varchar(1)) ENGINE=MyISAM;
@ -764,4 +764,34 @@ SELECT * FROM t1 STRAIGHT_JOIN (t2 JOIN t3 ON c = b AND b > 'z');
a b c
DROP TABLE t1,t2,t3;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
#
# Bug mdev-4366: impossible condition on an indexed column discovered after
# substitution of constant tables
# with optimizer_use_condition_selectivity=3
#
CREATE TABLE t1 (pk int PRIMARY KEY, a int);
INSERT INTO t1 VALUES
(1,4), (2,6), (3,3), (4,5);
CREATE TABLE t2 (b int);
INSERT INTO t2 VALUES (1), (7);
set optimizer_use_condition_selectivity=1;
EXPLAIN EXTENDED
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
Warnings:
Note 1003 select 1 AS `1` from `test`.`t1` join `test`.`t2` where 0
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
1
set optimizer_use_condition_selectivity=3;
EXPLAIN EXTENDED
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
Warnings:
Note 1003 select 1 AS `1` from `test`.`t1` join `test`.`t2` where 0
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
1
DROP TABLE t1,t2;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
set use_stat_tables=@save_use_stat_tables;

34
mysql-test/r/selectivity_innodb.result
View File

@ -758,10 +758,10 @@ set histogram_size=@save_histogram_size;
set histogram_type=@save_histogram_type;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
#
# Bug mdev-4367: join of a merged empty derived table
# Bug mdev-4367: 2-way join with an empty table
# when optimizer_use_condition_selectivity=3
#
SET optimizer_use_condition_selectivity=3;
set optimizer_use_condition_selectivity=3;
CREATE TABLE t1 (a varchar(1)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('j'),('k');
CREATE TABLE t2 (b varchar(1)) ENGINE=MyISAM;
@ -771,6 +771,36 @@ SELECT * FROM t1 STRAIGHT_JOIN (t2 JOIN t3 ON c = b AND b > 'z');
a b c
DROP TABLE t1,t2,t3;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
#
# Bug mdev-4366: impossible condition on an indexed column discovered after
# substitution of constant tables
# with optimizer_use_condition_selectivity=3
#
CREATE TABLE t1 (pk int PRIMARY KEY, a int);
INSERT INTO t1 VALUES
(1,4), (2,6), (3,3), (4,5);
CREATE TABLE t2 (b int);
INSERT INTO t2 VALUES (1), (7);
set optimizer_use_condition_selectivity=1;
EXPLAIN EXTENDED
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
Warnings:
Note 1003 select 1 AS `1` from `test`.`t1` join `test`.`t2` where 0
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
1
set optimizer_use_condition_selectivity=3;
EXPLAIN EXTENDED
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
Warnings:
Note 1003 select 1 AS `1` from `test`.`t1` join `test`.`t2` where 0
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
1
DROP TABLE t1,t2;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
set use_stat_tables=@save_use_stat_tables;
set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
SET SESSION STORAGE_ENGINE=DEFAULT;

31
mysql-test/t/selectivity.test
View File

@ -337,11 +337,11 @@ set histogram_type=@save_histogram_type;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
--echo #
--echo # Bug mdev-4367: join of a merged empty derived table
--echo # Bug mdev-4367: 2-way join with an empty table
--echo # when optimizer_use_condition_selectivity=3
--echo #
SET optimizer_use_condition_selectivity=3;
set optimizer_use_condition_selectivity=3;
CREATE TABLE t1 (a varchar(1)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('j'),('k');
@ -357,5 +357,32 @@ DROP TABLE t1,t2,t3;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
--echo #
--echo # Bug mdev-4366: impossible condition on an indexed column discovered after
--echo # substitution of constant tables
--echo # with optimizer_use_condition_selectivity=3
--echo #
CREATE TABLE t1 (pk int PRIMARY KEY, a int);
INSERT INTO t1 VALUES
(1,4), (2,6), (3,3), (4,5);
CREATE TABLE t2 (b int);
INSERT INTO t2 VALUES (1), (7);
set optimizer_use_condition_selectivity=1;
EXPLAIN EXTENDED
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
set optimizer_use_condition_selectivity=3;
EXPLAIN EXTENDED
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
DROP TABLE t1,t2;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
set use_stat_tables=@save_use_stat_tables;

14
sql/opt_range.cc
View File

@ -3325,11 +3325,8 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
table->cond_selectivity= 1.0;
#if 0
#else
if (table_records == 0)
DBUG_RETURN(FALSE);
#endif
if (thd->variables.optimizer_use_condition_selectivity > 2 &&
!bitmap_is_clear_all(used_fields))
@ -3338,6 +3335,7 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
MEM_ROOT alloc;
SEL_TREE *tree;
SEL_ARG **key, **end;
double rows;
uint idx= 0;
init_sql_alloc(&alloc, thd->variables.range_alloc_block_size, 0,
@ -3364,12 +3362,18 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
if (!tree)
goto free_alloc;
table->reginfo.impossible_range= 0;
if (tree->type == SEL_TREE::IMPOSSIBLE)
{
rows= 0;
table->reginfo.impossible_range= 1;
goto free_alloc;
}
for (key= tree->keys, end= key + param.keys; key != end; key++, idx++)
{
double rows;
if (*key)
{
table->reginfo.impossible_range= 0;
if ((*key)->type == SEL_ARG::IMPOSSIBLE)
{
rows= 0;