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7.6.3.1 Thread Pool Elements

MySQL Enterprise Thread Pool comprises these elements:

  • A plugin library file implements a plugin for the thread pool code as well as several associated monitoring tables that provide information about thread pool operation:

    • As of MySQL 8.0.14, the monitoring tables are Performance Schema tables; seeSection 29.12.16, “Performance Schema Thread Pool Tables”.

    • Prior to MySQL 8.0.14, the monitoring tables areINFORMATION_SCHEMA tables; seeSection 28.5, “INFORMATION_SCHEMA Thread Pool Tables”.

      TheINFORMATION_SCHEMA tables now are deprecated; expect them to be removed in a future version of MySQL. Applications should transition away from theINFORMATION_SCHEMA tables to the Performance Schema tables. For example, if an application uses this query:

      SELECT * FROM INFORMATION_SCHEMA.TP_THREAD_STATE;

      The application should use this query instead:

      SELECT * FROM performance_schema.tp_thread_state;
    Note

    If you do not load all the monitoring tables, some or all MySQL Enterprise Monitor thread pool graphs may be empty.

    For a detailed description of how the thread pool works, seeSection 7.6.3.3, “Thread Pool Operation”.

  • Several system variables are related to the thread pool. Thethread_handling system variable has a value ofloaded-dynamically when the server successfully loads the thread pool plugin.

    The other related system variables are implemented by the thread pool plugin and are not available unless it is enabled. For information about using these variables, seeSection 7.6.3.3, “Thread Pool Operation”, andSection 7.6.3.4, “Thread Pool Tuning”.

  • The Performance Schema has instruments that expose information about the thread pool and may be used to investigate operational performance. To identify them, use this query:

    SELECT * FROM performance_schema.setup_instrumentsWHERE NAME LIKE '%thread_pool%';

    For more information, seeChapter 29,MySQL Performance Schema.