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  1. MariaDB Server
  2. MDEV-21018

CPU Spikes to 50% and does not let up with RocksDB enabled



    • Type: Bug
    • Status: Open (View Workflow)
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 10.2.26, 10.2.29, 10.3.17, 10.3.20, 10.4.7, 10.4.10
    • Fix Version/s: 10.2, 10.3, 10.4
    • Labels:
    • Environment:
      Encountered on Windows, debugged on Windows.


      When upgrading to 10.4.7 and continuing on through 10.4.10 (and equivalent version of 10.2 and 10.3), if I have the RocksDB plugin enabled:

      plugin_load_add = ha_rocksdb

      Then as soon as I start that instance (a service in my case), the CPU usage spikes to 50% and does not let up until I kill the process.

      It may dip to 48-49%.

      If I start a second instance, they both end up taking ~49-50% each, and the CPU is pegged at 100%.

      If I start a third instance, the 3 generally end up using about ~32-33% each, and the CPU is pegged at 100%.

      The instances were only using about 32M RAM, and zero activity was occurring on them.

      I started Windows profiler, and attached it (and CPU stats gatherer), allowed it to run for 50 seconds, and analyzed. It showed that the CPU usage came from ha_rocksdb.dll.

      I then commented out the RocksDB plugin:

      #plugin_load_add = ha_rocksdb

      Restarted MariaDB.

      And then CPU was back to normal, roughly 0% in this case, since there was 0 activity.

      Comment: It is easy to remove if you enabled the plugin via the config file: simply remove or comment out the line, as above, and restart MariaDB.

      If you enabled it via the command line, then you need to uninstall it via the command line:

      UNINSTALL SONAME 'ha_rocksdb';

      However, this command is just hanging for me in this situation (i.e., when CPU is pegged out). It is essentially stuck. It did finally complete after about 20 minutes


        1. stack trace from debugger.png
          95 kB
          Chris Calender



            psergey Sergei Petrunia
            ccalender Chris Calender
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