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  1. Percona Server for MySQL
  2. PS-6140

High kernel cpu usage when using TokuDB under insert load

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    Details

    • Type: Bug
    • Status: Confirmation
    • Priority: High
    • Resolution: Unresolved
    • Affects Version/s: 8.0.17-8
    • Fix Version/s: None
    • Component/s: TokuDB
    • Labels:
      None
    • Environment:

      Ubuntu 18.04 LTS Desktop, Kernel 5.0, Ryzen 3970x (32 cores with HT), 128GB RAM, Intel Optane . Database version is actually 8.0.18 but was not available as select option.

      Description

      Scenario:

      10000 tables, all TokuDB, 10 columns per table, only primary key, 64 bit long, no other indexes

      Insert scenario is batch mode (2000 rows at once), once per minute for every table. During insert, the database eats more than 50% of whole CPU sitting in kernel (native_queued_spin_lock_slowpath).

      The issue appears both with or without tokudb_directio set and is fully absent from InnoDB. The kernel load is not constant but comes and goes (see netdata picture attached)

      Below are TokuDB parameters used (anything is default):

      tokudb_row_format = TOKUDB_ZLIB
      tokudb_cache_size = 32768M
      tokudb_lock_timeout = 30000
      tokudb_checkpointing_period = 1800
      tokudb_fs_reserve_percent = 1
      tokudb_directio = 1

       

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              People

              Assignee:
              lalit.choudhary Lalit Choudhary
              Reporter:
              sergiuhlihor Sergiu Hlihor
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                Dates

                Created:
                Updated: