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  1. MariaDB MaxScale
  2. MXS-401

Possible MaxScale hangs?

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Cannot Reproduce
    • 1.2.1
    • 2.0.0
    • Core
    • None
    • Galera, RWSplit, CentOS 7, MS Azure

    Description

      I'm trying to do some benchmarking through MaxScale using linkbench and I'm running into a problem where the linkbench threads will occasionally fail to close. I really can't tell whether this is a problem in MariaDB, a problem in MaxScale, or a problem in the Java client program (which I obviously did not write and have not studied). I don't think I ever see this hang when I have linkbench connected straight to the backend (bypassing MaxScale).

      Right now, I have a state where I've manually killed all app connections across all backends, but MaxScale still shows open sessions that are in "Session ready for routing" with associated DCBs in "DCB in the polling loop". Does it seem right that MaxScale sessions/DCBs would be in those states even when the associated threads on the backends have been killed?

      [mdbe@mdbec-max1 ~]$ maxadmin show sessions
      Session 8182 (0x1fa56f0)
             State:                  Session ready for routing
             Service:                CLI (0x1f947d0)
             Client DCB:             0x1fa5540
             Client Address:         127.0.0.1
             Connected:              Thu Oct  8 07:01:40 2015
             Idle:                           0 seconds
      Session 8002 (0x7f91084c1c60)
             State:                  Session ready for routing
             Service:                RW Split Router (0x1f95080)
             Client DCB:             0x7f910c4aefa0
             Client Address:         myapp@10.0.1.7
             Connected:              Thu Oct  8 05:44:41 2015
             Idle:                           4443 seconds
      Session 7874 (0x7f9108016b90)
             State:                  Session ready for routing
             Service:                RW Split Router (0x1f95080)
             Client DCB:             0x7f9108016830
             Client Address:         myapp@10.0.1.7
             Connected:              Thu Oct  8 05:44:40 2015
             Idle:                           4443 seconds
      Session 5 (0x1f93740)
             State:                  Listener Session
             Service:                CLI (0x1f947d0)
             Client DCB:             0x1f933a0
             Connected:              Wed Oct  7 13:48:33 2015
      Session 4 (0x1f93300)
             State:                  Listener Session
             Service:                RW Split Router (0x1f95080)
             Client DCB:             0x1f93860
             Connected:              Wed Oct  7 13:48:33 2015
      Session 3 (0x1f93b10)
             State:                  Listener Session
             Service:                RW Split Router (0x1f95080)
             Client DCB:             0x1f92ee0
             Connected:              Wed Oct  7 13:48:33 2015
      Session 2 (0x1f92d30)
             State:                  Listener Session
             Service:                Read Connection Router (0x1f96150)
             Client DCB:             0x1f92b60
             Connected:              Wed Oct  7 13:48:30 2015
      Session 1 (0x1f92ac0)
             State:                  Listener Session
             Service:                Read Connection Router (0x1f96150)
             Client DCB:             0x1fa0280
             Connected:              Wed Oct  7 13:48:30 2015

      $ for h in mdbec-db{1,2,3}; do ssh $h mysql -t -u root -p5mA6txkHXo7vAXn/hDOn -e "'show processlist'"; done
      +-------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      | Id    | User            | Host            | db   | Command | Time  | State              | Info             | Progress |
      +-------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      |     1 | system user     |                 | NULL | Sleep   |  4077 | committed 27226826 | NULL             |    0.000 |
      |     2 | system user     |                 | NULL | Sleep   | 62845 | wsrep aborter idle | NULL             |    0.000 |
      |     4 | system user     |                 | NULL | Sleep   |  4077 | committed 27226820 | NULL             |    0.000 |
      |     5 | system user     |                 | NULL | Sleep   |  4077 | committed 27226823 | NULL             |    0.000 |
      |     6 | system user     |                 | NULL | Sleep   |  4077 | committed 27226825 | NULL             |    0.000 |
      |     7 | system user     |                 | NULL | Sleep   |  4077 | committed 27226822 | NULL             |    0.000 |
      |     8 | system user     |                 | NULL | Sleep   |  4077 | committed 27226827 | NULL             |    0.000 |
      |     9 | system user     |                 | NULL | Sleep   |  4077 | committed 27226824 | NULL             |    0.000 |
      |    10 | system user     |                 | NULL | Sleep   |  4077 | committed 27226821 | NULL             |    0.000 |
      | 16122 | root            | localhost       | NULL | Sleep   |  1766 |                    | NULL             |    0.000 |
      | 16132 | maxscalemonitor | 10.0.1.11:38129 | NULL | Sleep   |     0 |                    | NULL             |    0.000 |
      | 16133 | root            | localhost       | NULL | Query   |     0 | init               | show processlist |    0.000 |
      +-------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      +------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      | Id   | User            | Host            | db   | Command | Time  | State              | Info             | Progress |
      +------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      |    1 | system user     |                 | NULL | Sleep   | 62441 | wsrep aborter idle | NULL             |    0.000 |
      |    2 | system user     |                 | NULL | Sleep   |  7108 | committed 25608867 | NULL             |    0.000 |
      |    4 | system user     |                 | NULL | Sleep   |  7108 | committed 25608866 | NULL             |    0.000 |
      |    5 | system user     |                 | NULL | Sleep   |  7108 | committed 25608871 | NULL             |    0.000 |
      |    6 | system user     |                 | NULL | Sleep   |  7108 | committed 25608869 | NULL             |    0.000 |
      |    7 | system user     |                 | NULL | Sleep   |  7108 | committed 25608870 | NULL             |    0.000 |
      |    8 | system user     |                 | NULL | Sleep   |  7108 | committed 25608872 | NULL             |    0.000 |
      |   10 | system user     |                 | NULL | Sleep   |  7109 | committed 25608865 | NULL             |    0.000 |
      |   11 | system user     |                 | NULL | Sleep   |  7108 | committed 25608868 | NULL             |    0.000 |
      | 8183 | root            | localhost       | NULL | Sleep   |  1772 |                    | NULL             |    0.000 |
      | 8186 | maxscalemonitor | 10.0.1.11:34503 | NULL | Sleep   |     1 |                    | NULL             |    0.000 |
      | 8188 | root            | localhost       | NULL | Query   |     0 | init               | show processlist |    0.000 |
      +------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      +------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      | Id   | User            | Host            | db   | Command | Time  | State              | Info             | Progress |
      +------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+
      |    1 | system user     |                 | NULL | Sleep   | 61417 | wsrep aborter idle | NULL             |    0.000 |
      |    2 | system user     |                 | NULL | Sleep   |  4080 | committed 27226821 | NULL             |    0.000 |
      |    4 | system user     |                 | NULL | Sleep   |  4080 | committed 27226826 | NULL             |    0.000 |
      |    5 | system user     |                 | NULL | Sleep   |  4080 | committed 27226822 | NULL             |    0.000 |
      |    6 | system user     |                 | NULL | Sleep   |  4080 | committed 27226825 | NULL             |    0.000 |
      |    7 | system user     |                 | NULL | Sleep   |  4080 | committed 27226820 | NULL             |    0.000 |
      |    8 | system user     |                 | NULL | Sleep   |  4080 | committed 27226824 | NULL             |    0.000 |
      |    9 | system user     |                 | NULL | Sleep   |  4080 | committed 27226823 | NULL             |    0.000 |
      |   11 | system user     |                 | NULL | Sleep   |  4080 | committed 27226827 | NULL             |    0.000 |
      |   12 | maxscalemonitor | 10.0.1.11:56629 | NULL | Sleep   |     0 |                    | NULL             |    0.000 |
      | 8180 | root            | localhost       | NULL | Sleep   |   552 |                    | NULL             |    0.000 |
      | 8183 | root            | localhost       | NULL | Query   |     0 | init               | show processlist |    0.000 |
      +------+-----------------+-----------------+------+---------+-------+--------------------+------------------+----------+

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            johan.wikman Johan Wikman
            kolbe Kolbe Kegel (Inactive)
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              Updated:
              Resolved:

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