Performance Schema Thread Pool Tables The number of statements executed. This number is incremented when a statement starts executing, not when it finishes. The number of statements received that were queued for execution. This does not count statements that the thread group was able to begin executing immediately without queuing, which can happen under the conditions described in Section 5.6.3.3, “Thread Pool Operation” . • QUERIES_QUEUED • THREADS_STARTED • PRIO_KICKUPS The number of threads started. The number of statements that have been moved from low-priority queue to high-priority queue based on the value of the  thread_pool_prio_kickup_timer  system variable. If this number increases quickly, consider increasing the value of that variable. A quickly increasing counter means that the priority system is not keeping transactions from starting too early. For  InnoDB , this most likely means deteriorating performance due to too many concurrent transactions.. • STALLED_QUERIES_EXECUTED • BECOME_RESERVE_THREAD • BECOME_CONSUMER_THREAD • WAKE_THREAD_STALL_CHECKER • BECOME_WAITING_THREAD The number of times threads have been assigned the reserve thread role. The number of times thread have been assigned the consumer thread role. The number of statements that have become defined as stalled due to executing for longer than the value of the  thread_pool_stall_limit  system variable. The number of times threads have been assigned the waiter thread role. When statements are queued, this happens very often, even in normal operation, so rapid increases in this value are normal in the case of a highly loaded system where statements are queued up. The number of times the stall check thread decided to wake or create a thread to possibly handle some statements or take care of the waiter thread role. The number of  THD_WAIT_SLEEP  waits. These occur when threads go to sleep (for example, by calling the  SLEEP()  function). • SLEEP_WAITS • DISK_IO_WAITS • ROW_LOCK_WAITS The number of  THD_WAIT_DISKIO  waits. These occur when threads perform disk I/O that is likely to not hit the file system cache. Such waits occur when the buffer pool reads and writes data to disk, not for normal reads from and writes to files. 5040