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Diffstat (limited to 'mysql-test/r/range.result')
| -rw-r--r-- | mysql-test/r/range.result | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/mysql-test/r/range.result b/mysql-test/r/range.result index 64e00521cd2..ad8aec7383a 100644 --- a/mysql-test/r/range.result +++ b/mysql-test/r/range.result @@ -1653,4 +1653,48 @@ a b 0 0 1 1 DROP TABLE t1; +# +# Bug#50939: Loose Index Scan unduly relies on engine to remember range +# endpoints +# +CREATE TABLE t1 ( +a INT, +b INT, +KEY ( a, b ) +) PARTITION BY HASH (a) PARTITIONS 1; +CREATE TABLE t2 ( +a INT, +b INT, +KEY ( a, b ) +); +INSERT INTO t1 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5); +INSERT INTO t1 SELECT a + 5, b + 5 FROM t1; +INSERT INTO t1 SELECT a + 10, b + 10 FROM t1; +INSERT INTO t1 SELECT a + 20, b + 20 FROM t1; +INSERT INTO t1 SELECT a + 40, b + 40 FROM t1; +INSERT INTO t2 SELECT * FROM t1; +# plans should be identical +EXPLAIN SELECT a, MAX(b) FROM t1 WHERE a IN (10,100) GROUP BY a; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 range a a 5 NULL 1 Using where; Using index for group-by +EXPLAIN SELECT a, MAX(b) FROM t2 WHERE a IN (10,100) GROUP BY a; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t2 range a a 5 NULL 2 Using where; Using index for group-by +FLUSH status; +SELECT a, MAX(b) FROM t1 WHERE a IN (10, 100) GROUP BY a; +a MAX(b) +10 10 +# Should be no more than 4 reads. +SHOW status LIKE 'handler_read_key'; +Variable_name Value +Handler_read_key 4 +FLUSH status; +SELECT a, MAX(b) FROM t2 WHERE a IN (10, 100) GROUP BY a; +a MAX(b) +10 10 +# Should be no more than 4 reads. +SHOW status LIKE 'handler_read_key'; +Variable_name Value +Handler_read_key 4 +DROP TABLE t1, t2; End of 5.1 tests |