The stage summary tables provide aggregated information about stage events:

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 stage 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:

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 MySQL 5.6.3.