Details
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Bug
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Status: Closed (View Workflow)
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Critical
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Resolution: Fixed
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5.5.36, 10.0.9
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None
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None
Description
Using mariadb-10.0.9-linux-x86_64.tar.gz.
MariaDB [test]> show global status like 'com_insert';
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+---------------+--------+
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| Variable_name | Value |
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+---------------+--------+
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| Com_insert | 646298 |
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+---------------+--------+
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1 row in set (0.00 sec)
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|
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MariaDB [test]> stop slave;
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Query OK, 0 rows affected (0.00 sec)
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|
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MariaDB [test]> show global status like 'com_insert';
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+---------------+-------+
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| Variable_name | Value |
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+---------------+-------+
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| Com_insert | 0 |
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+---------------+-------+
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1 row in set (0.00 sec)
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Attachments
Activity
Problem was that global status was not updated when slave thread thd was deleted.
Fix pushed into 5.5. Will be in 10.0.10 when we do next merge from 5.5
The problem was introduced in 5.5 tree by the following revision:
revno: 3601revision-id: wlad@montyprogram.com-20121220231237-0xv7egt3s225bx7jparent: timour@askmonty.org-20121220203840-ofoavsm70g8ouk0mcommitter: Vladislav Vaintroub <wlad@montyprogram.com>branch nick: 5.5timestamp: Fri 2012-12-21 00:12:37 +0100message:MDEV-3945 - do not hold LOCK_thread_count when freeing THD.The patch decreases the duration of LOCK_thread_count, so it is not hold during THD destructor and freeing memory.This mutex now only protects the integrity of threads list, when removing THD from it, and thread_count variable.The add_to_status() function that updates global status during client disconnect, is now correctly protected by the LOCK_status mutex.Benchmark : in a "non-persistent" sysbench test (oltp_ro with reconnect after each query), ~ 25% more connects/disconnects were measuredI agree that the effect is bad and must be fixed, but given that it had survived for over an year without affecting anybody heavily enough to be noticed, I demote it from Blocker