Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Won't Fix
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10.1.26, 10.0.32
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None
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GNU/Linux Debian 8 Jessie
GNU/Linux Debian 9 stretch
Description
Hello
I have just applied the PTI patch on the OS and it is causing a massive difference in the execution time of a specific query.
Disabling and reenabling PTI enables me to reproduce the difference at will :
PTI disabled : 7s
PTI enabled : 87s
The query :
SELECT * FROM `test` as b1 WHERE b1.`dateFin` > '2018-01-24' AND NOT EXISTS (SELECT 1 FROM `test` as b2 WHERE b2.`ip` = b1.`ip` AND b2.`dateFin` > b1.`dateFin`); |
Explain doesn't help much :
+------+--------------------+-------+------+---------------+------+---------+------+------+-------------+
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| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
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+------+--------------------+-------+------+---------------+------+---------+------+------+-------------+
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| 1 | PRIMARY | b1 | ALL | NULL | NULL | NULL | NULL | 4499 | Using where |
|
| 2 | DEPENDENT SUBQUERY | b2 | ALL | NULL | NULL | NULL | NULL | 4499 | Using where |
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+------+--------------------+-------+------+---------------+------+---------+------+------+-------------+
|
Can't see any report matching that kind of difference so far so i'm wondering what's up
Attachments
Issue Links
- relates to
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- Closed
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