TP_GROUP_ID

The thread group ID. This is a unique key within the table.

CONSUMER THREADS

The number of consumer threads. There is at most one thread ready to start executing if the active threads become stalled or blocked.

RESERVE_THREADS

The number of threads in the reserved state. This means that they are not started until there is a need to wake a new thread and there is no consumer thread. This is where most threads end up when the thread group has created more threads than needed for normal operation. Often a thread group needs additional threads for a short while and then does not need them again for a while. In this case, they go into the reserved state and remain until needed again. They take up some extra memory resources, but no extra computing resources.

CONNECT_THREAD_COUNT

The number of threads that are processing or waiting to process connection initialization and authentication. There can be a maximum of four connection threads per thread group; these threads expire after a period of inactivity.

This column was added in MySQL 5.7.18.

CONNECTION_COUNT

The number of connections using this thread group.

QUEUED_QUERIES

The number of statements waiting in the high-priority queue.

QUEUED_TRANSACTIONS

The number of statements waiting in the low-priority queue. These are the initial statements for transactions that have not started, so they also represent queued transactions.

STALL_LIMIT

The value of the thread_pool_stall_limit system variable for the thread group. This is the same value for all thread groups.

PRIO_KICKUP_TIMER

The value of the thread_pool_prio_kickup_timer system variable for the thread group. This is the same value for all thread groups.

ALGORITHM

The value of the thread_pool_algorithm system variable for the thread group. This is the same value for all thread groups.

THREAD_COUNT

The number of threads started in the thread pool as part of this thread group.

ACTIVE_THREAD_COUNT

The number of threads active in executing statements.

STALLED_THREAD_COUNT

The number of stalled statements in the thread group. A stalled statement could be executing, but from a thread pool perspective it is stalled and making no progress. A long-running statement quickly ends up in this category.

WAITING_THREAD_NUMBER

If there is a thread handling the polling of statements in the thread group, this specifies the thread number within this thread group. It is possible that this thread could be executing a statement.

OLDEST_QUEUED

How long in milliseconds the oldest queued statement has been waiting for execution.

MAX_THREAD_IDS_IN_GROUP

The maximum thread ID of the threads in the group. This is the same as MAX(TP_THREAD_NUMBER) for the threads when selected from the TP_THREAD_STATE table. That is, these two queries are equivalent:

SELECT TP_GROUP_ID, MAX_THREAD_IDS_IN_GROUP
FROM TP_THREAD_GROUP_STATE;

SELECT TP_GROUP_ID, MAX(TP_THREAD_NUMBER)
FROM TP_THREAD_STATE GROUP BY TP_GROUP_ID;