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Bug#42846: wrong result returned for range scan when using

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covering index
      
When two range predicates were combined under an OR
predicate, the algorithm tried to merge overlapping ranges
into one. But the case when a range overlapped several other
ranges was not handled. This lead to

1) ranges overlapping, which gave repeated results and 
2) a range that overlapped several other ranges was cut off.  

Fixed by 

1) Making sure that a range got an upper bound equal to the
next range with a greater minimum.
2) Removing a continue statement
This commit is contained in:
Martin Hansson
2009-10-09 11:30:40 +02:00
parent bf711a743e
commit eded60737d
4 changed files with 379 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

179
mysql-test/r/range.result
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@@ -1219,3 +1219,182 @@ explain select * from t2 where a=1000 and b<11;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref a a 5 const 502 Using where
drop table t1, t2;
CREATE TABLE t1( a INT, b INT, KEY( a, b ) );
CREATE TABLE t2( a INT, b INT, KEY( a, b ) );
CREATE TABLE t3( a INT, b INT, KEY( a, b ) );
INSERT INTO t1( a, b )
VALUES (0, 1), (1, 2), (1, 4), (2, 3), (5, 0), (9, 7);
INSERT INTO t2( a, b )
VALUES ( 1, 1), ( 2, 1), ( 3, 1), ( 4, 1), ( 5, 1),
( 6, 1), ( 7, 1), ( 8, 1), ( 9, 1), (10, 1),
(11, 1), (12, 1), (13, 1), (14, 1), (15, 1),
(16, 1), (17, 1), (18, 1), (19, 1), (20, 1);
INSERT INTO t2 SELECT a, 2 FROM t2 WHERE b = 1;
INSERT INTO t2 SELECT a, 3 FROM t2 WHERE b = 1;
INSERT INTO t2 SELECT -1, -1 FROM t2;
INSERT INTO t2 SELECT -1, -1 FROM t2;
INSERT INTO t2 SELECT -1, -1 FROM t2;
INSERT INTO t3
VALUES (1, 0), (2, 0), (3, 0), (4, 0), (5, 0),
(6, 0), (7, 0), (8, 0), (9, 0), (10, 0);
INSERT INTO t3 SELECT * FROM t3 WHERE a = 10;
INSERT INTO t3 SELECT * FROM t3 WHERE a = 10;
SELECT * FROM t1 WHERE
3 <= a AND a < 5 OR
5 < a AND b = 3 OR
3 <= a;
a b
5 0
9 7
EXPLAIN
SELECT * FROM t1 WHERE
3 <= a AND a < 5 OR
5 < a AND b = 3 OR
3 <= a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 3 Using where; Using index
SELECT * FROM t1 WHERE
3 <= a AND a < 5 OR
5 <= a AND b = 3 OR
3 <= a;
a b
5 0
9 7
EXPLAIN
SELECT * FROM t1 WHERE
3 <= a AND a < 5 OR
5 <= a AND b = 3 OR
3 <= a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 4 Using where; Using index
SELECT * FROM t1 WHERE
3 <= a AND a <= 5 OR
5 <= a AND b = 3 OR
3 <= a;
a b
5 0
9 7
EXPLAIN
SELECT * FROM t1 WHERE
3 <= a AND a <= 5 OR
5 <= a AND b = 3 OR
3 <= a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 3 Using where; Using index
SELECT * FROM t1 WHERE
3 <= a AND a <= 5 OR
3 <= a;
a b
5 0
9 7
EXPLAIN
SELECT * FROM t1 WHERE
3 <= a AND a <= 5 OR
3 <= a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 3 Using where; Using index
SELECT * FROM t2 WHERE
5 <= a AND a < 10 AND b = 1 OR
15 <= a AND a < 20 AND b = 3
OR
1 <= a AND b = 1;
a b
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 1
12 1
13 1
14 1
15 1
15 3
16 1
16 3
17 1
17 3
18 1
18 3
19 1
19 3
20 1
EXPLAIN
SELECT * FROM t2 WHERE
5 <= a AND a < 10 AND b = 1 OR
15 <= a AND a < 20 AND b = 3
OR
1 <= a AND b = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range a a 10 NULL 50 Using where; Using index
SELECT * FROM t2 WHERE
5 <= a AND a < 10 AND b = 2 OR
15 <= a AND a < 20 AND b = 3
OR
1 <= a AND b = 1;
a b
1 1
2 1
3 1
4 1
5 1
5 2
6 1
6 2
7 1
7 2
8 1
8 2
9 1
9 2
10 1
11 1
12 1
13 1
14 1
15 1
15 3
16 1
16 3
17 1
17 3
18 1
18 3
19 1
19 3
20 1
EXPLAIN
SELECT * FROM t2 WHERE
5 <= a AND a < 10 AND b = 2 OR
15 <= a AND a < 20 AND b = 3
OR
1 <= a AND b = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range a a 10 NULL 50 Using where; Using index
SELECT * FROM t3 WHERE
5 <= a AND a < 10 AND b = 3 OR
a < 5 OR
a < 10;
a b
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
9 0
EXPLAIN
SELECT * FROM t3 WHERE
5 <= a AND a < 10 AND b = 3 OR
a < 5 OR
a < 10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range a a 5 NULL 8 Using where; Using index
DROP TABLE t1, t2, t3;