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  1. MariaDB Server
  2. MDEV-25513

raise systemd LimitNOFILE limits to match server defaults (~32768)

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      Description

      Starting MariaDB with default configuration causes the following problems:

      • "[Warning] Could not increase number of max_open_files to more than 16384 (request: 32186)"
      • silently reduces table_open_cache_instances from 8 (default) to 4

      Default Server System Variables:

      • extra_max_connections = 1
      • max_connections = 151
      • table_open_cache = 2000
      • table_open_cache_instances = 8
      • thread_pool_size = 4

      LimitNOFILE=16834 is in the following files:

      • support-files/mariadb.service.in
      • support-files/mariadb@.service.in

      Looking at sql/mysqld.cc lines 3837-3917:
      wanted_files= (extra_files + max_connections + extra_max_connections +
      tc_size * 2 * tc_instances);
      wanted_files+= threadpool_size;

      Plugging in the default values:
      wanted_files = (30 + 151 + 1 + 2000 * 2 * 8 + 4) = 32186

      However, systemd configuration has LimitNOFILE = 16384, which is far smaller.

      I suggest increasing LimitNOFILE to 32768.

      Thank you!
      Daniel Lewart
      Urbana, Illinois

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            Assignee:
            danblack Daniel Black
            Reporter:
            lewart Daniel Lewart
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