Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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10.1.9, 10.1(EOL)
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None
Description
After the upgrade from 10.1.8 to 10.1.9 or 10.1.10, frequent queries involving index merge went crazy.
Here is a repeatable test case :
DROP TABLE if exists t; |
CREATE TABLE t |
(
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id bigint PRIMARY KEY AUTO_INCREMENT, |
a bigint, |
b int, |
c bigint, |
KEY(a), KEY(b), KEY(c) |
) ENGINE = InnoDB;
|
|
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INSERT INTO t(a, b, c) |
VALUES (rand() * 44, rand() * 283, rand() * 131072); |
|
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INSERT INTO t(a, b, c) |
VALUES (rand() * 44, rand() * 283, rand() * 131072); |
|
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REPLACE INTO t(a, b, c) |
SELECT rand() * 44, rand() * 283, rand() * 131072 |
FROM t t1, |
t t2,
|
t t3,
|
t t4,
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t t5,
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t t6,
|
t t7,
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t t8,
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t t9,
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t t10,
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t t11,
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t t12,
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t t13,
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t t14,
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t t15,
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t t16,
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t t17;
|
ANALYZE TABLE t; |
|
|
EXPLAIN
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SELECT DISTINCT c |
FROM t |
WHERE b = 5 AND a = 10\G |
10.1.8 :
*************************** 1. row ***************************
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id: 1
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select_type: SIMPLE
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table: t
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type: index_merge
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possible_keys: a,b
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key: b,a
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key_len: 5,9
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ref: NULL
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rows: 10
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Extra: Using intersect(b,a); Using where; Using temporary
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1 row in set (0.00 sec)
|
10.1.9 :
*************************** 1. row ***************************
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id: 1
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select_type: SIMPLE
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table: t
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type: index
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possible_keys: a,b
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key: c
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key_len: 9
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ref: NULL
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rows: 131109
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Extra: Using where
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1 row in set (0.00 sec)
|