Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-26440

Missing connection id value in I_S.thread_pool_queues

Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • 10.5.10, 10.5.11, 10.5.12
    • 10.5.13, 10.6.5
    • Server
    • None

    Description

      As far as I can tell, column I_S.thread_pool_queues.connection_id is supposed to contain ids of connections that are waiting for available worker threads.
      The issue is that I haven't observed any values in this column besides NULL.
      That makes it not quite possible to discern connections that are really sleeping from those that have queued queries.

      Can be reproduced using official docker image.

      MARIADB_VERSION=10.5.12 ./test-in-contaner.sh ./thread-pool-queues.sh > ./result.txt

      Result:

      cat result.txt 
      +----------+----------+----------+---------------+----------------------------+
      		 
      | GROUP_ID | POSITION | PRIORITY | CONNECTION_ID | QUEUEING_TIME_MICROSECONDS |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      |        0 |        0 |        0 |          NULL |                      18301 |
      		 
      |        0 |        1 |        0 |          NULL |                      16621 |
      		 
      |        0 |        2 |        0 |          NULL |                      16214 |
      		 
      |        0 |        3 |        0 |          NULL |                      15903 |
      		 
      |        0 |        4 |        0 |          NULL |                      14968 |
      		 
      |        0 |        5 |        0 |          NULL |                      14366 |
      		 
      |        0 |        6 |        0 |          NULL |                      12835 |
      		 
      |        0 |        7 |        0 |          NULL |                      11526 |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      | GROUP_ID | POSITION | PRIORITY | CONNECTION_ID | QUEUEING_TIME_MICROSECONDS |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      |        0 |        0 |        1 |          NULL |                      56000 |
      		 
      |        0 |        1 |        1 |          NULL |                      56000 |
      		 
      |        0 |        2 |        1 |          NULL |                      56000 |
      		 
      |        0 |        3 |        1 |          NULL |                      56000 |
      		 
      |        0 |        4 |        1 |          NULL |                      56000 |
      		 
      |        0 |        5 |        1 |          NULL |                      56000 |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      | GROUP_ID | POSITION | PRIORITY | CONNECTION_ID | QUEUEING_TIME_MICROSECONDS |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      |        0 |        0 |        1 |          NULL |                    1068634 |
      		 
      |        0 |        1 |        1 |          NULL |                    1068634 |
      		 
      |        0 |        2 |        1 |          NULL |                    1068634 |
      		 
      |        0 |        3 |        1 |          NULL |                    1068634 |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      | GROUP_ID | POSITION | PRIORITY | CONNECTION_ID | QUEUEING_TIME_MICROSECONDS |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      |        0 |        0 |        0 |          NULL |                    2081406 |
      		 
      |        0 |        1 |        0 |          NULL |                    2081406 |
      		 
      |        0 |        2 |        0 |          NULL |                    2081406 |
      		 
      |        0 |        3 |        1 |          NULL |                     584074 |
      		 
      |        0 |        4 |        1 |          NULL |                     584074 |
      		 
      |        0 |        5 |        1 |          NULL |                     584074 |
      		 
      |        0 |        6 |        1 |          NULL |                     466012 |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      | GROUP_ID | POSITION | PRIORITY | CONNECTION_ID | QUEUEING_TIME_MICROSECONDS |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      |        0 |        0 |        0 |          NULL |                    3093475 |
      		 
      |        0 |        1 |        0 |          NULL |                    1596143 |
      		 
      |        0 |        2 |        0 |          NULL |                    1596143 |
      		 
      |        0 |        3 |        0 |          NULL |                    1596143 |
      		 
      |        0 |        4 |        0 |          NULL |                    1478081 |
      		 
      |        0 |        5 |        1 |          NULL |                     920131 |
      		 
      |        0 |        6 |        1 |          NULL |                     460330 |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      | GROUP_ID | POSITION | PRIORITY | CONNECTION_ID | QUEUEING_TIME_MICROSECONDS |
      		 
      +----------+----------+----------+---------------+----------------------------+
      		 
      |        0 |        0 |        0 |          NULL |                    2608249 |
      		 
      |        0 |        1 |        0 |          NULL |                    2608249 |
      		 
      |        0 |        2 |        0 |          NULL |                    2490187 |
      		 
      |        0 |        3 |        0 |          NULL |                    1932237 |
      		 
      |        0 |        4 |        0 |          NULL |                    1472436 |
      		 
      |        0 |        5 |        1 |          NULL |                     836087 |
      		 
      |        0 |        6 |        1 |          NULL |                     345225 |
      		 
      +----------+----------+----------+---------------+----------------------------+

      Attachments

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-24757 Potential null pointer dereference in I_S.thread_pool_queues

          • Major - Major loss of function.
          • Closed

          Activity

            People

              wlad Vladislav Vaintroub
              narkq Alex Sladkov
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              Dates

                Created:
                Updated:
                Resolved:

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