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Bug #28591: MySQL need not sort the records in case of 

ORDER BY primary_key on InnoDB table

Queries that use an InnoDB secondary index to retrieve
data don't need to sort in case of ORDER BY primary key
if the secondary index is compared to constant(s).
They can also skip sorting if ORDER BY contains both the
the secondary key parts and the primary key parts (in
that order).
This is because InnoDB returns the rows in order of the
primary key for rows with the same values of the secondary
key columns.
Fixed by preventing temp table sort for the qualifying 
queries.


mysql-test/r/innodb_mysql.result:
  Bug #28591: test case
mysql-test/t/innodb_mysql.test:
  Bug #28591: test case
sql/sql_select.cc:
  Bug #28591: Use the primary key as suffix when testing
  if the key can be used for ORDER BY on supporting engines.
sql/table.cc:
  Bug #28591: can use the primary key
  as a suffix for the secondary keys
parent d1dd69f5
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Inline Side-by-side
Showing with 309 additions and 2 deletions
mysql-test/r/innodb_mysql.result
View file @ a3c979b0
......@@ -735,4 +735,249 @@ COUNT(*)
3072
set @@sort_buffer_size=default;
DROP TABLE t1,t2;
CREATE TABLE t1 (a int, b int, PRIMARY KEY (a), KEY bkey (b)) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,2),(3,2),(2,2),(4,2),(5,2),(6,2),(7,2),(8,2);
INSERT INTO t1 SELECT a + 8, 2 FROM t1;
INSERT INTO t1 SELECT a + 16, 1 FROM t1;
EXPLAIN SELECT * FROM t1 WHERE b=2 ORDER BY a;
id 1
select_type SIMPLE
table t1
type ref
possible_keys bkey
key bkey
key_len 5
ref const
rows 16
Extra Using where; Using index
SELECT * FROM t1 WHERE b=2 ORDER BY a;
a b
1 2
2 2
3 2
4 2
5 2
6 2
7 2
8 2
9 2
10 2
11 2
12 2
13 2
14 2
15 2
16 2
EXPLAIN SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY a;
id 1
select_type SIMPLE
table t1
type range
possible_keys bkey
key bkey
key_len 5
ref NULL
rows 16
Extra Using where; Using index; Using filesort
SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY a;
a b
1 2
2 2
3 2
4 2
5 2
6 2
7 2
8 2
9 2
10 2
11 2
12 2
13 2
14 2
15 2
16 2
17 1
18 1
19 1
20 1
21 1
22 1
23 1
24 1
25 1
26 1
27 1
28 1
29 1
30 1
31 1
32 1
EXPLAIN SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY b,a;
id 1
select_type SIMPLE
table t1
type range
possible_keys bkey
key bkey
key_len 5
ref NULL
rows 16
Extra Using where; Using index
SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY b,a;
a b
17 1
18 1
19 1
20 1
21 1
22 1
23 1
24 1
25 1
26 1
27 1
28 1
29 1
30 1
31 1
32 1
1 2
2 2
3 2
4 2
5 2
6 2
7 2
8 2
9 2
10 2
11 2
12 2
13 2
14 2
15 2
16 2
CREATE TABLE t2 (a int, b int, c int, PRIMARY KEY (a), KEY bkey (b,c))
ENGINE=InnoDB;
INSERT INTO t2 VALUES (1,1,1),(3,1,1),(2,1,1),(4,1,1);
INSERT INTO t2 SELECT a + 4, 1, 1 FROM t2;
INSERT INTO t2 SELECT a + 8, 1, 1 FROM t2;
EXPLAIN SELECT * FROM t2 WHERE b=1 ORDER BY a;
id 1
select_type SIMPLE
table t2
type ref
possible_keys bkey
key bkey
key_len 5
ref const
rows 8
Extra Using where; Using index; Using filesort
SELECT * FROM t2 WHERE b=1 ORDER BY a;
a b c
1 1 1
2 1 1
3 1 1
4 1 1
5 1 1
6 1 1
7 1 1
8 1 1
9 1 1
10 1 1
11 1 1
12 1 1
13 1 1
14 1 1
15 1 1
16 1 1
EXPLAIN SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY a;
id 1
select_type SIMPLE
table t2
type ref
possible_keys bkey
key bkey
key_len 10
ref const,const
rows 8
Extra Using where; Using index
SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY a;
a b c
1 1 1
2 1 1
3 1 1
4 1 1
5 1 1
6 1 1
7 1 1
8 1 1
9 1 1
10 1 1
11 1 1
12 1 1
13 1 1
14 1 1
15 1 1
16 1 1
EXPLAIN SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY b,c,a;
id 1
select_type SIMPLE
table t2
type ref
possible_keys bkey
key bkey
key_len 10
ref const,const
rows 8
Extra Using where; Using index
SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY b,c,a;
a b c
1 1 1
2 1 1
3 1 1
4 1 1
5 1 1
6 1 1
7 1 1
8 1 1
9 1 1
10 1 1
11 1 1
12 1 1
13 1 1
14 1 1
15 1 1
16 1 1
EXPLAIN SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY c,a;
id 1
select_type SIMPLE
table t2
type ref
possible_keys bkey
key bkey
key_len 10
ref const,const
rows 8
Extra Using where; Using index
SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY c,a;
a b c
1 1 1
2 1 1
3 1 1
4 1 1
5 1 1
6 1 1
7 1 1
8 1 1
9 1 1
10 1 1
11 1 1
12 1 1
13 1 1
14 1 1
15 1 1
16 1 1
DROP TABLE t1,t2;
End of 5.0 tests
mysql-test/t/innodb_mysql.test
View file @ a3c979b0
......@@ -741,4 +741,37 @@ set @@sort_buffer_size=default;
DROP TABLE t1,t2;
#
# Bug #28591: MySQL need not sort the records in case of ORDER BY
# primary_key on InnoDB table
#
CREATE TABLE t1 (a int, b int, PRIMARY KEY (a), KEY bkey (b)) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,2),(3,2),(2,2),(4,2),(5,2),(6,2),(7,2),(8,2);
INSERT INTO t1 SELECT a + 8, 2 FROM t1;
INSERT INTO t1 SELECT a + 16, 1 FROM t1;
query_vertical EXPLAIN SELECT * FROM t1 WHERE b=2 ORDER BY a;
SELECT * FROM t1 WHERE b=2 ORDER BY a;
query_vertical EXPLAIN SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY a;
SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY a;
query_vertical EXPLAIN SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY b,a;
SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY b,a;
CREATE TABLE t2 (a int, b int, c int, PRIMARY KEY (a), KEY bkey (b,c))
ENGINE=InnoDB;
INSERT INTO t2 VALUES (1,1,1),(3,1,1),(2,1,1),(4,1,1);
INSERT INTO t2 SELECT a + 4, 1, 1 FROM t2;
INSERT INTO t2 SELECT a + 8, 1, 1 FROM t2;
query_vertical EXPLAIN SELECT * FROM t2 WHERE b=1 ORDER BY a;
SELECT * FROM t2 WHERE b=1 ORDER BY a;
query_vertical EXPLAIN SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY a;
SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY a;
query_vertical EXPLAIN SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY b,c,a;
SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY b,c,a;
query_vertical EXPLAIN SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY c,a;
SELECT * FROM t2 WHERE b=1 AND c=1 ORDER BY c,a;
DROP TABLE t1,t2;
--echo End of 5.0 tests
sql/sql_select.cc
View file @ a3c979b0
......@@ -12009,6 +12009,7 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
key_part_end=key_part+table->key_info[idx].key_parts;
key_part_map const_key_parts=table->const_key_parts[idx];
int reverse=0;
my_bool on_primary_key= FALSE;
DBUG_ENTER("test_if_order_by_key");
for (; order ; order=order->next, const_key_parts>>=1)
......@@ -12023,7 +12024,30 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
for (; const_key_parts & 1 ; const_key_parts>>= 1)
key_part++;
if (key_part == key_part_end || key_part->field != field)
if (key_part == key_part_end)
{
/*
We are at the end of the key. Check if the engine has the primary
key as a suffix to the secondary keys. If it has continue to check
the primary key as a suffix.
*/
if (!on_primary_key &&
(table->file->table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
table->s->primary_key != MAX_KEY)
{
on_primary_key= TRUE;
key_part= table->key_info[table->s->primary_key].key_part;
key_part_end=key_part+table->key_info[table->s->primary_key].key_parts;
const_key_parts=table->const_key_parts[table->s->primary_key];
for (; const_key_parts & 1 ; const_key_parts>>= 1)
key_part++;
}
else
DBUG_RETURN(0);
}
if (key_part->field != field)
DBUG_RETURN(0);
/* set flag to 1 if we can use read-next on key, else to -1 */
......@@ -12034,7 +12058,8 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
reverse=flag; // Remember if reverse
key_part++;
}
*used_key_parts= (uint) (key_part - table->key_info[idx].key_part);
*used_key_parts= on_primary_key ? table->key_info[idx].key_parts :
(uint) (key_part - table->key_info[idx].key_part);
if (reverse == -1 && !(table->file->index_flags(idx, *used_key_parts-1, 1) &
HA_READ_PREV))
reverse= 0; // Index can't be used
......
sql/table.cc
View file @ a3c979b0
......@@ -780,7 +780,11 @@ int openfrm(THD *thd, const char *name, const char *alias, uint db_stat,
the primary key, then we can use any key to find this column
*/
if (ha_option & HA_PRIMARY_KEY_IN_READ_INDEX)
{
field->part_of_key= share->keys_in_use;
if (field->part_of_sortkey.is_set(key))
field->part_of_sortkey= share->keys_in_use;
}
}
if (field->key_length() != key_part->length)
{
......
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