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  1. MariaDB Server
  2. MDEV-13019

scrub log cause high system load

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      The server is a brand new, dedicated mysql box, and here are the relevant variables in my.cnf

      innodb_encryption_threads = 8
      innodb_background_scrub_data_check_interval = 3600
      innodb_background_scrub_data_compressed = 1
      innodb_background_scrub_data_interval = 86400
      innodb_background_scrub_data_uncompressed = 1
      innodb_immediate_scrub_data_uncompressed = 1
      innodb_scrub_log = 1
      innodb_scrub_log_speed = 50000

      After the service restarted, the total CPU usage is 0, and after a short while(several minutes, an hour, not quite sure), the total CPU usage grows to 15, and system load is up to 8. And after I comment the above variables, the system is back to normal.

      Is there anything wrong with my configuration?

      perf top -p ${pid}
      Samples: 1M of event 'cycles:ppp', Event count (approx.): 278084696592
      Overhead Shared Object Symbol
      30.93% mysqld [.] fil_crypt_thread
      29.82% mysqld [.] ut_delay
      16.56% [kernel] [k] _raw_spin_lock
      1.41% mysqld [.] PolicyMutex<TTASEventMutex<GenericPolicy> >::enter

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              Assignee:
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              Reporter:
              mxu Michael Xu
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