THREAD_POOL_STATS

Overview

In 23.08 ES, 23.07 ES, 10.6 ES, 10.6 CS, 10.5 ES, 10.5 CS:

Provides information about thread pool statistics.

In 23.08 ES, 23.07 ES, 10.6 ES, 10.5 ES:

Provides information about thread pool statistics.

In 10.4 ES, 10.4 CS, 10.3 ES, 10.3 CS, 10.2 ES, 10.2 CS:

Not present

In 10.4 ES:

Not present

USAGE

DETAILS

SYNONYMS

SCHEMA

CREATE TEMPORARY TABLE `THREAD_POOL_STATS` (
  `GROUP_ID` int(6) NOT NULL,
  `THREAD_CREATIONS` bigint(19) NOT NULL,
  `THREAD_CREATIONS_DUE_TO_STALL` bigint(19) NOT NULL,
  `WAKES` bigint(19) NOT NULL,
  `WAKES_DUE_TO_STALL` bigint(19) NOT NULL,
  `THROTTLES` bigint(19) NOT NULL,
  `STALLS` bigint(19) NOT NULL,
  `POLLS_BY_LISTENER` bigint(19) NOT NULL,
  `POLLS_BY_WORKER` bigint(19) NOT NULL,
  `DEQUEUES_BY_LISTENER` bigint(19) NOT NULL,
  `DEQUEUES_BY_WORKER` bigint(19) NOT NULL
)

Column Descriptions

Variable

Description

GROUP_ID

ID of the group this row is for

THREAD_CREATIONS

The number of threads created for this group so far

THREAD_CREATIONS_DUE_TO_STALL

How often a thread was created as another one was identified as stalled

WAKES

How often a standby thread has been woken up

WAKES_DUE_TO_STALLS

How often standby thread wakeup was due to another thread having been found to be stalled

THROTTLES

How often thread creation was throttled

STALLS

How often a stalled thread was detected

POLLS_BY_LISTENER

The number of network "polls" done by the listener thread. The "poll" a name of OS dependent efficient system call to pick up readable sockets - in context of MariaDB, readable socket means client sent a request, which was not handled yet.

POLLS_BY_WORKER

If queue is empty, a worker thread might try a non-blocking "poll" (see previous section for description) before going to sleep. The number of those "polls" is this value.

DEQUEUES_BY_LISTENER

The number of dequeues, done by listener thread. Recall that each group has a queue, and the operation of removing entry from this queue is called a "dequeue" . Usually, listener thread populates (enqueues works to) that queue, and workers dequeue and handle request, but if the load is light, it is more efficient if listener both polls and handles the work, as it saves on inter-thread communication. If thread_pool_dedicated_listener is ON, this number would always be 0.

DEQUEUES_BY_WORKER

The number of dequeue operations (see previous section for explanation) done by worker threads.

PARAMETERS

SKYSQL

PRIVILEGES

EXAMPLES

ERROR HANDLING

FEATURE INTERACTION

RESPONSES

DIAGNOSIS

ISO 9075:2016

CHANGE HISTORY

Release Series

History

23.08 Enterprise

  • Present starting in MariaDB Enterprise Server 23.08.0.

23.07 Enterprise

  • Present starting in MariaDB Enterprise Server 23.07.0.

10.6 Enterprise

  • Present starting in MariaDB Enterprise Server 10.6.4-1.

  • Schema changed in MariaDB Enterprise Server 10.6.7-3: ...

10.6 Community

  • Present starting in MariaDB Community Server 10.6.0.

  • Schema changed in MariaDB Community Server 10.6.6: ...

10.5 Enterprise

  • Added in MariaDB Enterprise Server 10.5.3-1.

  • Schema changed in MariaDB Enterprise Server 10.5.15-10: ...

10.5 Community

  • Added in MariaDB Community Server 10.5.0.

  • Schema changed in MariaDB Community Server 10.5.14: ...

10.4 Enterprise

  • Not present.

10.4 Community

  • Not present.

10.3 Enterprise

  • Not present.

10.3 Community

  • Not present.

10.2 Enterprise

  • Not present.

10.2 Community

  • Not present.

Release Series

History

23.08 Enterprise

  • Present starting in MariaDB Enterprise Server 23.08.0.

23.07 Enterprise

  • Present starting in MariaDB Enterprise Server 23.07.0.

10.6 Enterprise

  • Present starting in MariaDB Enterprise Server 10.6.4-1.

  • Schema changed in MariaDB Enterprise Server 10.6.7-3: ...

10.5 Enterprise

  • Added in MariaDB Enterprise Server 10.5.3-1.

  • Schema changed in MariaDB Enterprise Server 10.5.15-10: ...

10.4 Enterprise

  • Not present.

EXTERNAL REFERENCES