Stage Summary Tables

The stage summary tables provide aggregate information about stage waits:

events_stages_summary_by_thread_by_event_name: Stage waits summarized per thread and event name
events_stages_summary_global_by_event_name: Stage waits summarized per event name

For example:

mysql> SELECT * FROM events_stages_summary_global_by_event_name\G
...
*************************** 5. row ***************************
 EVENT_NAME: stage/sql/checking permissions
 COUNT_STAR: 57
SUM_TIMER_WAIT: 26501888880
MIN_TIMER_WAIT: 7317456
AVG_TIMER_WAIT: 464945295
MAX_TIMER_WAIT: 12858936792
...
*************************** 9. row ***************************
 EVENT_NAME: stage/sql/closing tables
 COUNT_STAR: 37
SUM_TIMER_WAIT: 662606568
MIN_TIMER_WAIT: 1593864
AVG_TIMER_WAIT: 17907891
MAX_TIMER_WAIT: 437977248
...

TRUNCATE TABLE is permitted for summary tables. It resets the counters to zero rather than removing rows.

The stage summary tables have these grouping columns to indicate how events are aggregated:

events_stages_summary_global_by_event_name has an EVENT_NAME column. Each row summarizes events for a given instrument.
events_stages_summary_by_thread_by_event_name has THREAD_ID and EVENT_NAME columns. Each row summarizes events for a given thread instrument instance.

The stage summary tables have these summary columns containing aggregated values: COUNT_STAR, SUM_TIMER_WAIT, MIN_TIMER_WAIT, AVG_TIMER_WAIT, and MAX_TIMER_WAIT. These columns are analogous to the columns of the same names in the events_waits_summary_global_by_event_name and events_waits_summary_by_thread_by_event_name tables, except that the stage summary tables aggregate waits from events_stages_current rather than events_waits_current.

These tables were added in MariaDB 5.6.3.

Stage Summary Tables

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