The Ultimate Guide to High Availability with MariaDB

Performance Schema events_waits_summary_by_host_by_event_name Table

The Performance Schema events_waits_summary_by_host_by_event_name table contains wait events summarized by host and event name. It contains the following columns:

ColumnDescription
HOSTHost. Used together with EVENT_NAME for grouping events.
EVENT_NAMEEvent name. Used together with USER and HOST for grouping events.
COUNT_STARNumber of summarized events
SUM_TIMER_WAITTotal wait time of the summarized events that are timed.
MIN_TIMER_WAITMinimum wait time of the summarized events that are timed.
AVG_TIMER_WAITAverage wait time of the summarized events that are timed.
MAX_TIMER_WAITMaximum wait time of the summarized events that are timed.

The *_TIMER_WAIT columns only calculate results for timed events, as non-timed events have a NULL wait time.

Example

SELECT * FROM events_waits_summary_by_host_by_event_name\G
...
*************************** 610. row ***************************
          HOST: NULL
    EVENT_NAME: wait/io/socket/sql/server_unix_socket
    COUNT_STAR: 0
SUM_TIMER_WAIT: 0
MIN_TIMER_WAIT: 0
AVG_TIMER_WAIT: 0
MAX_TIMER_WAIT: 0
*************************** 611. row ***************************
          HOST: NULL
    EVENT_NAME: wait/io/socket/sql/client_connection
    COUNT_STAR: 0
SUM_TIMER_WAIT: 0
MIN_TIMER_WAIT: 0
AVG_TIMER_WAIT: 0
MAX_TIMER_WAIT: 0
*************************** 612. row ***************************
          HOST: NULL
    EVENT_NAME: idle
    COUNT_STAR: 0
SUM_TIMER_WAIT: 0
MIN_TIMER_WAIT: 0
AVG_TIMER_WAIT: 0
MAX_TIMER_WAIT: 0

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