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.

For a detailed description of how the thread pool works, see Section 5.5.3.3, “Thread Pool Operation”.

The INFORMATION_SCHEMA tables are named TP_THREAD_STATE, TP_THREAD_GROUP_STATE, and TP_THREAD_GROUP_STATS. These tables provide information about thread pool operation. For more information, see Section 21.32, “INFORMATION_SCHEMA Thread Pool Tables”.

Several system variables are related to the thread pool. The thread_handling system variable has a value of loaded-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, see Section 5.5.3.3, “Thread Pool Operation”, and Section 5.5.3.4, “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_instruments
WHERE NAME LIKE '%thread_pool%';

For more information, see Chapter 22, MySQL Performance Schema.