Bug #54782 Performance schema per thread accounting and thread cache

• Submitted: 24 Jun 2010 15:31
• Modified: 4 Aug 2010 20:08
• Reporter: Marc ALFF
• Status: Closed
• Category: MySQL Server: Performance Schema
• Severity: S3 (Non-critical)
• Version: 5.5.3-m3, 5.5.4-m3
• OS: Any
• Assigned to: Marc ALFF
• CPU Architecture: Any

[24 Jun 2010 15:31] Marc ALFF

Description:
Reported by Ranger.

When the server calls cache_thread(),
a posix thread running connection 1 is parked,
waits for a user job to pick up (THD),
then runs the job from connection 2.

The performance schema instrumentation then leaks from connection 1 to 2,
and continues to accumulate statistics on the old connection.

How to repeat:
Code review in mysqld.cc, cache_thread.

[25 Jun 2010 7:57] Bugs System

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/112172

3271 Marc Alff	2010-06-25
      Bug#54782 Performance schema per thread accounting and thread cache
      
      Before this fix, when using the performance schema with the thread cache,
      a thread executing connection A, then cached, then executing connection B
      would account B actions with the statistics for A.
      
      With this fix:
      - the instrumentation for connection A is cleaned up when A completes,
      - a new instrumentation for connection B is created when B is executed
        from a cached thread.

[25 Jun 2010 21:03] Christopher Powers

Bug fix reviewed.

[28 Jun 2010 23:50] Marc ALFF

Pushed into mysql-next-mr-bugfixing

[16 Jul 2010 12:51] Bugs System

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/113753

3120 Marc Alff	2010-07-16
      Bug#54782 Performance schema per thread accounting and thread cache
      
      Backport from mysql-next-mr (5.6) to mysql-trunk (5.5)

[16 Jul 2010 19:29] Marc ALFF

Now also queued in mysql-trunk-bugfixing (5.5)

[23 Jul 2010 12:25] Bugs System

Pushed into mysql-trunk 5.5.6-m3 (revid:[e-mail]-20100723121820-jryu2fuw3pc53q9w) (version source revid:[e-mail]-20100531152341-x2d4hma644icamh1) (merge vers: 5.5.5-m3) (pib:18)

[23 Jul 2010 12:32] Bugs System

Pushed into mysql-next-mr (revid:[e-mail]-20100723121929-90e9zemk3jkr2ocy) (version source revid:[e-mail]-20100531152341-x2d4hma644icamh1) (pib:18)

[29 Jul 2010 18:52] Paul DuBois

Noted in 5.5.6 changelog.

Performance Schema event collection for a thread could "leak" from
one connection to another if the thread was used for one connection,
then cached, then reused for another connection.

[4 Aug 2010 8:07] Bugs System

Pushed into mysql-trunk 5.6.1-m4 (revid:alik@ibmvm-20100804080001-bny5271e65xo34ig) (version source revid:[e-mail]-20100531152341-x2d4hma644icamh1) (merge vers: 5.5.5-m3) (pib:18)

[4 Aug 2010 8:23] Bugs System

Pushed into mysql-trunk 5.6.1-m4 (revid:alik@ibmvm-20100804081533-c1d3rbipo9e8rt1s) (version source revid:[e-mail]-20100531152341-x2d4hma644icamh1) (merge vers: 5.5.5-m3) (pib:18)

[4 Aug 2010 20:08] Paul DuBois

Bug is not present in any released 5.6.x version.