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Bug #31001: ORDER BY DESC in InnoDB not working

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The optimizer sets index traversal in reverse order only if there are 
used key parts that are not compared to a constant.
However using the primary key as an ORDER BY suffix rendered the check
incomplete : going in reverse order must still be used even if 
all the parts of the secondary key are compared to a constant.

Fixed by relaxing the check and set reverse traversal even when all
the secondary index keyparts are compared to a const.
Also account for the case when all the primary keys are compared to a
constant.
This commit is contained in:
gkodinov/kgeorge@magare.gmz
2007-09-14 18:20:17 +03:00
parent c66df1c169
commit dc02820236
3 changed files with 127 additions and 1 deletions
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23
mysql-test/include/mix1.inc
View File

@ -939,6 +939,29 @@ alter table t1 add index(a(1024));
show create table t1;
drop table t1;
#
# Bug #31001: ORDER BY DESC in InnoDB not working
#
CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a), INDEX b (b)) ENGINE=InnoDB;
INSERT INTO t1(a,b) VALUES (1,1), (2,2), (3,2);
#The two queries below should produce different results, but they don't.
query_vertical EXPLAIN SELECT * FROM t1 WHERE b=2 ORDER BY a ASC;
SELECT * FROM t1 WHERE b=2 ORDER BY a ASC;
query_vertical EXPLAIN SELECT * FROM t1 WHERE b=2 ORDER BY a DESC;
SELECT * FROM t1 WHERE b=2 ORDER BY a DESC;
query_vertical EXPLAIN SELECT * FROM t1 ORDER BY b ASC, a ASC;
SELECT * FROM t1 ORDER BY b ASC, a ASC;
query_vertical EXPLAIN SELECT * FROM t1 ORDER BY b DESC, a DESC;
SELECT * FROM t1 ORDER BY b DESC, a DESC;
query_vertical EXPLAIN SELECT * FROM t1 ORDER BY b ASC, a DESC;
SELECT * FROM t1 ORDER BY b ASC, a DESC;
query_vertical EXPLAIN SELECT * FROM t1 ORDER BY b DESC, a ASC;
SELECT * FROM t1 ORDER BY b DESC, a ASC;
DROP TABLE t1;
--echo End of 5.0 tests
# Fix for BUG#19243 "wrong LAST_INSERT_ID() after ON DUPLICATE KEY

97
mysql-test/r/innodb_mysql.result
View File

@ -1123,6 +1123,103 @@ t1 CREATE TABLE `t1` (
KEY `a` (`a`(255))
) ENGINE=InnoDB DEFAULT CHARSET=utf8
drop table t1;
CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a), INDEX b (b)) ENGINE=InnoDB;
INSERT INTO t1(a,b) VALUES (1,1), (2,2), (3,2);
EXPLAIN SELECT * FROM t1 WHERE b=2 ORDER BY a ASC;
id 1
select_type SIMPLE
table t1
type ref
possible_keys b
key b
key_len 5
ref const
rows 1
Extra Using where; Using index
SELECT * FROM t1 WHERE b=2 ORDER BY a ASC;
a b
2 2
3 2
EXPLAIN SELECT * FROM t1 WHERE b=2 ORDER BY a DESC;
id 1
select_type SIMPLE
table t1
type ref
possible_keys b
key b
key_len 5
ref const
rows 1
Extra Using where; Using index
SELECT * FROM t1 WHERE b=2 ORDER BY a DESC;
a b
3 2
2 2
EXPLAIN SELECT * FROM t1 ORDER BY b ASC, a ASC;
id 1
select_type SIMPLE
table t1
type index
possible_keys NULL
key b
key_len 5
ref NULL
rows 3
Extra Using index
SELECT * FROM t1 ORDER BY b ASC, a ASC;
a b
1 1
2 2
3 2
EXPLAIN SELECT * FROM t1 ORDER BY b DESC, a DESC;
id 1
select_type SIMPLE
table t1
type index
possible_keys NULL
key b
key_len 5
ref NULL
rows 3
Extra Using index
SELECT * FROM t1 ORDER BY b DESC, a DESC;
a b
3 2
2 2
1 1
EXPLAIN SELECT * FROM t1 ORDER BY b ASC, a DESC;
id 1
select_type SIMPLE
table t1
type index
possible_keys NULL
key b
key_len 5
ref NULL
rows 3
Extra Using index; Using filesort
SELECT * FROM t1 ORDER BY b ASC, a DESC;
a b
1 1
3 2
2 2
EXPLAIN SELECT * FROM t1 ORDER BY b DESC, a ASC;
id 1
select_type SIMPLE
table t1
type index
possible_keys NULL
key b
key_len 5
ref NULL
rows 3
Extra Using index; Using filesort
SELECT * FROM t1 ORDER BY b DESC, a ASC;
a b
2 2
3 2
1 1
DROP TABLE t1;
End of 5.0 tests
CREATE TABLE `t2` (
`k` int(11) NOT NULL auto_increment,