29.12.16.4 The tp_thread_state Table

The tp_thread_state table has one row per thread created by the thread pool to handle connections.

The tp_thread_state table has these columns:

• TP_GROUP_ID

  The thread group ID.

• TP_THREAD_NUMBER

  The ID of the thread within its thread group. TP_GROUP_ID and TP_THREAD_NUMBER together provide a unique key within the table.

• PROCESS_COUNT

  The 10ms interval in which the statement that uses this thread is currently executing. 0 means no statement is executing, 1 means it is in the first 10ms, and so forth.

• WAIT_TYPE

  The type of wait for the thread. NULL means the thread is not blocked. Otherwise, the thread is blocked by a call to thd_wait_begin() and the value specifies the type of wait. The xxx_WAIT columns of the tp_thread_group_stats table accumulate counts for each wait type.

  The WAIT_TYPE value is a string that describes the type of wait, as shown in the following table.

  Table 29.4 tp_thread_state Table WAIT_TYPE Values

  Wait Type	Meaning
  THD_WAIT_SLEEP	Waiting for sleep
  THD_WAIT_DISKIO	Waiting for Disk IO
  THD_WAIT_ROW_LOCK	Waiting for row lock
  THD_WAIT_GLOBAL_LOCK	Waiting for global lock
  THD_WAIT_META_DATA_LOCK	Waiting for metadata lock
  THD_WAIT_TABLE_LOCK	Waiting for table lock
  THD_WAIT_USER_LOCK	Waiting for user lock
  THD_WAIT_BINLOG	Waiting for binlog
  THD_WAIT_GROUP_COMMIT	Waiting for group commit
  THD_WAIT_SYNC	Waiting for fsync

  
  

• TP_THREAD_TYPE

  The type of thread. The value shown in this column is one of CONNECTION_HANDLER_WORKER_THREAD, LISTENER_WORKER_THREAD, QUERY_WORKER_THREAD, or TIMER_WORKER_THREAD.

• THREAD_ID

  This thread's unique identifier. The value is the same as that used in the THREAD_ID column of the Performance Schema threads table.

• TIME_OF_ATTACH:

  Timestamp showing when the thread was attached, if attached to a connection; otherwise NULL.

• MARKED_STALLED:

  This is True if this thread has been marked as stalled by the stall checker thread.

• STATE:

  Possible values depend on the type of thread, as shown by the TP_THREAD_TYPE column:

  • For worker threads (QUERY_WORKER_THREAD), this is one of Managing, Polling, Processing Direct, Processing Queued, Sleeping Consumer, or Sleeping Reserve.

  • For connection handler threads (CONNECTION_HANDLER_WORKER_THREAD), this is one of CH Processing, CH Sleeping Timed, or CH Sleeping Indefinite.

  • For the stall checker thread (TIMER_WORKER_THREAD), this is one of SC Checking, SC Sleeping Short, or SC Sleeping Long.

• EVENT_COUNT:

  The accumulated number of events processed by this thread.

• ACCUMULATED_EVENT_TIME:

  The wall clock time spent processing events.

• EXEC_COUNT:

  The accumulated number of queries (statements) passed to the server for execution.

• ACCUMULATED_EXEC_TIME:

  The wall clock time spent processing queries by the server.

The tp_thread_state table has one index; this is a unique index on the TP_GROUP_ID and TP_THREAD_NUMBER columns.

TRUNCATE TABLE is not permitted for the tp_thread_state table.