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  1. Data Management
  2. DM-15320

Merge Qserv code performance updates


    • Type: Story
    • Status: Done
    • Resolution: Done
    • Fix Version/s: None
    • Component/s: Qserv
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      Data Access and Database


      This ticket is concerned with merging changes to the code made to improve performance. There was a large drop in performance between KPM20 and KPM30 in the cluster at in2p3. Performance was restored to previous level for the LSST dataset, but only in the case where join queries were not included in the batches of test queries. Single join queries run quickly, but when run with a group of queries the entire system slows down significantly. This is thought to be caused by MariaDB not having sufficient resources and is still being sorted out. MariaDB optimizations should improve the situation. The number of computers in the cluster at in2p3 may simple not have enough resources to meet the KPM30 requirements.

      Code was modified to add instrumentation for diagnosis and other changes were made to improve performance. Most of the changes were in qdisp (where the threading model was changed significantly between KPM20 and KPM30), wsched (as testing showed some significant problems), and memman (used by wsched and its mlock calls took significant time).

      Part of the performance issue was configuration values appropriate for the PDAC were applied to the in2p3 cluster. Configuration files are part of the container. Kubernetes has tools for writing the appropriate configuration files to individual systems and they should be used as soon as practical.


          Container Issues



              • Assignee:
                jgates John Gates
                vaikunth Vaikunth Thukral
                Andy Hanushevsky
                Andy Hanushevsky, Fritz Mueller, Igor Gaponenko, John Gates, Vaikunth Thukral
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                  Summary Panel