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Commit 00816a96 authored by Igor Babaev's avatar Igor Babaev
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Fixed bug mdev-5028. 

Apparently in a general case a short-cut for the distinct optimization
is invalid if join buffers are used to join tables after the tables whose
values are to selected.
parent ec7da156
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Showing with 179 additions and 8 deletions
mysql-test/r/distinct.result
View file @ 00816a96
...@@ -879,3 +879,113 @@ NULL ...@@ -879,3 +879,113 @@ NULL
7 7
drop view v; drop view v;
drop table t1, t2; drop table t1, t2;
CREATE TABLE t1 (
id int, i1 int, i2 int DEFAULT 0,
d1 date DEFAULT '2000-01-01', d2 date DEFAULT '2000-01-01',
t1 time DEFAULT '00:00:00', t2 time DEFAULT '00:00:00',
dt1 datetime NOT NULL DEFAULT '2000-01-01 00:00:00',
dt2 datetime NOT NULL DEFAULT '2000-01-01 00:00:00',
c1 varchar(1) NOT NULL, c2 varchar(1) NOT NULL
) ENGINE=MyISAM;
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
INSERT INTO t1 (id,i1,c1,c2) VALUES
(1,7,'t','t'),(2,4,'k','k'),(3,2,'e','e'),(4,0,'i','i'),(5,1,'t','t'),(6,91,'m','m'),
(7,6,'z','z'),(8,3,'c','c'),(9,6,'i','i'),(10,8,'v','v'), (11,1,'l','l'),(12,4,'j','j'),
(13,5,'w','w'),(14,0,'r','r'),(15,7,'o','o'),(16,9,'o','o'),(17,7,'u','u'),(18,6,'f','f'),
(19,0,'l','l'),(20,6,'g','g'),(21,1,'e','e'),(22,7,'y','y'),(23,0,'p','p'),(24,6,'v','v'),
(25,5,'d','d'),(26,9,'i','i'),(27,5,'z','z'),(28,2,'q','q'),(29,4,'j','j'),(30,9,'m','m'),
(31,8,'d','d'),(32,5,'r','r'),(33,1,'r','r'),(34,1,'k','k'),(35,4,'p','p'),(36,2,'x','x'),
(37,5,'w','w'),(38,0,'k','k'),(39,7,'y','y'),(40,4,'p','p'),(41,9,'l','l'),(42,2,'u','u'),
(43,3,'r','r'),(44,5,'y','y'),(45,3,'u','u'),(46,9,'t','t'),(47,8,'f','f'),(48,2,'f','f'),
(49,2,'q','q'),(50,6,'v','v'),(51,6,'u','u'),(52,0,'b','b'),(53,1,'n','n'),(54,2,'p','p'),
(55,0,'y','y'),(56,1,'l','l'),(57,1,'c','c'),(58,0,'d','d'),(59,2,'y','y'),(60,7,'l','l'),
(61,6,'m','m'),(62,9,'q','q'),(63,0,'j','j'),(64,3,'u','u'),(65,4,'w','w'),(66,5,'p','p'),
(67,8,'z','z'),(68,5,'u','u'),(69,7,'b','b'),(70,0,'f','f'),(71,6,'u','u'),(72,1,'i','i'),
(73,9,'s','s'),(74,3,'y','y'),(75,5,'s','s'),(76,8,'x','x'),(77,3,'s','s'),(78,3,'l','l'),
(79,8,'b','b'),(80,0,'p','p'),(81,9,'m','m'),(82,5,'k','k'),(83,7,'u','u'),(84,0,'y','y'),
(85,2,'x','x'),(86,5,'h','h'),(87,5,'j','j'),(88,5,'o','o'),(89,9,'o','o'),(90,1,'c','c'),
(91,7,'k','k'),(92,9,'t','t'),(93,3,'h','h'),(94,6,'g','g'),(95,9,'r','r'),(96,2,'i','i');
CREATE TABLE t2 (i INT) ENGINE=MyISAM;
INSERT INTO t2 VALUES (7),(8);
SELECT STRAIGHT_JOIN COUNT(DISTINCT t1.id) FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
COUNT(DISTINCT t1.id)
18
EXPLAIN EXTENDED
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 96 100.00 Using where; Using temporary
1 PRIMARY <derived2> ref key0 key0 5 test.t1.i1 9 100.00 Using where; Distinct
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00 Using where; Distinct; Using join buffer (flat, BNL join)
2 DERIVED t1 ALL NULL NULL NULL NULL 96 100.00
Warnings:
Note 1003 select straight_join distinct `test`.`t1`.`id` AS `id` from `test`.`t1` join `test`.`v1` join `test`.`t2` where ((`test`.`t2`.`i` = `v1`.`id`) and (`v1`.`i1` = `test`.`t1`.`i1`) and (`v1`.`id` <> 3))
set join_buffer_size=1024;
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
id
7
8
9
18
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24
43
45
50
51
61
64
71
74
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78
93
94
set join_buffer_size=1024*16;
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
id
7
9
18
20
24
8
50
51
61
43
45
71
64
74
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94
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set join_buffer_size=default;
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
id
7
9
18
20
24
50
51
61
71
94
8
43
45
64
74
77
78
93
DROP VIEW v1;
DROP TABLE t1,t2;
mysql-test/t/distinct.test
View file @ 00816a96
...@@ -682,3 +682,62 @@ select * from v; ...@@ -682,3 +682,62 @@ select * from v;
select distinct (select max(a) from t1 where alias.b = a) as field1 from t2 as alias group by field1; select distinct (select max(a) from t1 where alias.b = a) as field1 from t2 as alias group by field1;
drop view v; drop view v;
drop table t1, t2; drop table t1, t2;
#
# Bug mdev-5028: invalid distinct optimization when join buffer is used
#
CREATE TABLE t1 (
id int, i1 int, i2 int DEFAULT 0,
d1 date DEFAULT '2000-01-01', d2 date DEFAULT '2000-01-01',
t1 time DEFAULT '00:00:00', t2 time DEFAULT '00:00:00',
dt1 datetime NOT NULL DEFAULT '2000-01-01 00:00:00',
dt2 datetime NOT NULL DEFAULT '2000-01-01 00:00:00',
c1 varchar(1) NOT NULL, c2 varchar(1) NOT NULL
) ENGINE=MyISAM;
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
INSERT INTO t1 (id,i1,c1,c2) VALUES
(1,7,'t','t'),(2,4,'k','k'),(3,2,'e','e'),(4,0,'i','i'),(5,1,'t','t'),(6,91,'m','m'),
(7,6,'z','z'),(8,3,'c','c'),(9,6,'i','i'),(10,8,'v','v'), (11,1,'l','l'),(12,4,'j','j'),
(13,5,'w','w'),(14,0,'r','r'),(15,7,'o','o'),(16,9,'o','o'),(17,7,'u','u'),(18,6,'f','f'),
(19,0,'l','l'),(20,6,'g','g'),(21,1,'e','e'),(22,7,'y','y'),(23,0,'p','p'),(24,6,'v','v'),
(25,5,'d','d'),(26,9,'i','i'),(27,5,'z','z'),(28,2,'q','q'),(29,4,'j','j'),(30,9,'m','m'),
(31,8,'d','d'),(32,5,'r','r'),(33,1,'r','r'),(34,1,'k','k'),(35,4,'p','p'),(36,2,'x','x'),
(37,5,'w','w'),(38,0,'k','k'),(39,7,'y','y'),(40,4,'p','p'),(41,9,'l','l'),(42,2,'u','u'),
(43,3,'r','r'),(44,5,'y','y'),(45,3,'u','u'),(46,9,'t','t'),(47,8,'f','f'),(48,2,'f','f'),
(49,2,'q','q'),(50,6,'v','v'),(51,6,'u','u'),(52,0,'b','b'),(53,1,'n','n'),(54,2,'p','p'),
(55,0,'y','y'),(56,1,'l','l'),(57,1,'c','c'),(58,0,'d','d'),(59,2,'y','y'),(60,7,'l','l'),
(61,6,'m','m'),(62,9,'q','q'),(63,0,'j','j'),(64,3,'u','u'),(65,4,'w','w'),(66,5,'p','p'),
(67,8,'z','z'),(68,5,'u','u'),(69,7,'b','b'),(70,0,'f','f'),(71,6,'u','u'),(72,1,'i','i'),
(73,9,'s','s'),(74,3,'y','y'),(75,5,'s','s'),(76,8,'x','x'),(77,3,'s','s'),(78,3,'l','l'),
(79,8,'b','b'),(80,0,'p','p'),(81,9,'m','m'),(82,5,'k','k'),(83,7,'u','u'),(84,0,'y','y'),
(85,2,'x','x'),(86,5,'h','h'),(87,5,'j','j'),(88,5,'o','o'),(89,9,'o','o'),(90,1,'c','c'),
(91,7,'k','k'),(92,9,'t','t'),(93,3,'h','h'),(94,6,'g','g'),(95,9,'r','r'),(96,2,'i','i');
CREATE TABLE t2 (i INT) ENGINE=MyISAM;
INSERT INTO t2 VALUES (7),(8);
SELECT STRAIGHT_JOIN COUNT(DISTINCT t1.id) FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
EXPLAIN EXTENDED
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
set join_buffer_size=1024;
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
set join_buffer_size=1024*16;
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
set join_buffer_size=default;
SELECT STRAIGHT_JOIN DISTINCT t1.id FROM
t1, v1, t2 WHERE v1.id = t2.i AND t1.i1 = v1.i1 AND t2.i != 3;
DROP VIEW v1;
DROP TABLE t1,t2;
sql/sql_cursor.cc
View file @ 00816a96
...@@ -398,7 +398,7 @@ Sensitive_cursor::open(JOIN *join_arg) ...@@ -398,7 +398,7 @@ Sensitive_cursor::open(JOIN *join_arg)
#ifndef DBUG_OFF #ifndef DBUG_OFF
JOIN_TAB *first_tab= first_linear_tab(join, WITHOUT_CONST_TABLES); JOIN_TAB *first_tab= first_linear_tab(join, WITHOUT_CONST_TABLES);
DBUG_ASSERT(first_tab->table->reginfo.not_exists_optimize == 0); DBUG_ASSERT(first_tab->table->reginfo.not_exists_optimize == 0);
DBUG_ASSERT(first_tab->not_used_in_distinct == 0); DBUG_ASSERT(first_tab->shortcut_for_distinct == 0);
/* /*
null_row is set only if row not found and it's outer join: should never null_row is set only if row not found and it's outer join: should never
happen for the first table in join_tab list happen for the first table in join_tab list
......
sql/sql_select.cc
View file @ 00816a96
...@@ -1811,9 +1811,10 @@ int JOIN::init_execution() ...@@ -1811,9 +1811,10 @@ int JOIN::init_execution()
JOIN_TAB *last_join_tab= join_tab + top_join_tab_count - 1; JOIN_TAB *last_join_tab= join_tab + top_join_tab_count - 1;
do do
{ {
if (used_tables & last_join_tab->table->map) if (used_tables & last_join_tab->table->map ||
last_join_tab->use_join_cache)
break; break;
last_join_tab->not_used_in_distinct=1; last_join_tab->shortcut_for_distinct= true;
} while (last_join_tab-- != join_tab); } while (last_join_tab-- != join_tab);
/* Optimize "select distinct b from t1 order by key_part_1 limit #" */ /* Optimize "select distinct b from t1 order by key_part_1 limit #" */
if (order && skip_sort_order) if (order && skip_sort_order)
...@@ -7983,7 +7984,7 @@ JOIN::make_simple_join(JOIN *parent, TABLE *temp_table) ...@@ -7983,7 +7984,7 @@ JOIN::make_simple_join(JOIN *parent, TABLE *temp_table)
join_tab->last_inner= 0; join_tab->last_inner= 0;
join_tab->first_unmatched= 0; join_tab->first_unmatched= 0;
join_tab->ref.key = -1; join_tab->ref.key = -1;
join_tab->not_used_in_distinct=0; join_tab->shortcut_for_distinct= false;
join_tab->read_first_record= join_init_read_record; join_tab->read_first_record= join_init_read_record;
join_tab->preread_init_done= FALSE; join_tab->preread_init_done= FALSE;
join_tab->join= this; join_tab->join= this;
...@@ -16223,7 +16224,7 @@ static enum_nested_loop_state ...@@ -16223,7 +16224,7 @@ static enum_nested_loop_state
evaluate_join_record(JOIN *join, JOIN_TAB *join_tab, evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
int error) int error)
{ {
bool not_used_in_distinct=join_tab->not_used_in_distinct; bool shortcut_for_distinct= join_tab->shortcut_for_distinct;
ha_rows found_records=join->found_records; ha_rows found_records=join->found_records;
COND *select_cond= join_tab->select_cond; COND *select_cond= join_tab->select_cond;
bool select_cond_result= TRUE; bool select_cond_result= TRUE;
...@@ -16362,7 +16363,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab, ...@@ -16362,7 +16363,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
was not in the field list; In this case we can abort if was not in the field list; In this case we can abort if
we found a row, as no new rows can be added to the result. we found a row, as no new rows can be added to the result.
*/ */
if (not_used_in_distinct && found_records != join->found_records) if (shortcut_for_distinct && found_records != join->found_records)
DBUG_RETURN(NESTED_LOOP_NO_MORE_ROWS); DBUG_RETURN(NESTED_LOOP_NO_MORE_ROWS);
} }
else else
......
sql/sql_select.h
View file @ 00816a96
...@@ -314,7 +314,8 @@ typedef struct st_join_table { ...@@ -314,7 +314,8 @@ typedef struct st_join_table {
uint used_null_fields; uint used_null_fields;
uint used_uneven_bit_fields; uint used_uneven_bit_fields;
enum join_type type; enum join_type type;
bool cached_eq_ref_table,eq_ref_table,not_used_in_distinct; bool cached_eq_ref_table,eq_ref_table;
bool shortcut_for_distinct;
bool sorted; bool sorted;
/* /*
If it's not 0 the number stored this field indicates that the index If it's not 0 the number stored this field indicates that the index
......
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