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

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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.
This commit is contained in:
gkodinov/kgeorge@magare.gmz
2007-07-20 21:05:29 +03:00
parent 17654758a4
commit 8fc401e21f
4 changed files with 309 additions and 2 deletions
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33
mysql-test/t/innodb_mysql.test
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@ -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