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  1. MariaDB Server
  2. MDEV-17346

parallel slave start and stop races to workers disappeared

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 10.1
    • Fix Version/s: 10.1.37
    • Component/s: Replication
    • Labels:
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      Description

      The bug appears as a slave SQL thread hanging in
      rpl_parallel_thread_pool::get_thread() while there are no slave worker
      threads to awake it.

      The reason of the hang is that at the parallel slave worker pool
      activation the being stared SQL thread could read the worker pool size
      concurrently with pool deactivation. At reading the SQL thread did not
      employ necessary protection from a race.

      One way to fix it is to make the SQL thread at the pool activation first
      to grab the same lock as potential deactivator also does prior
      to access the pool size.

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              Assignee:
              Elkin Andrei Elkin
              Reporter:
              Elkin Andrei Elkin
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                Dates

                Created:
                Updated:
                Resolved:

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