select * from performance_schema.events_waits_summary_by_instance
where event_name like 'Wait/Synch/%' limit 1;
select * from performance_schema.events_waits_summary_by_instance
where event_name='FOO';
select * from performance_schema.events_waits_summary_by_instance
order by count_star limit 1;
select * from performance_schema.events_waits_summary_by_instance
order by count_star desc limit 1;
select * from performance_schema.events_waits_summary_by_instance
where min_timer_wait > 0 order by count_star limit 1;
select * from performance_schema.events_waits_summary_by_instance
where min_timer_wait > 0 order by count_star desc limit 1;
insert into performance_schema.events_waits_summary_by_instance
set event_name='FOO', object_instance_begin=0,
count_star=1, sum_timer_wait=2, min_timer_wait=3,
avg_timer_wait=4, max_timer_wait=5;
ERROR 42000: INSERT command denied to user 'root'@'localhost' for table `performance_schema`.`events_waits_summary_by_instance`
update performance_schema.events_waits_summary_by_instance
set count_star=12;
ERROR 42000: UPDATE command denied to user 'root'@'localhost' for table `performance_schema`.`events_waits_summary_by_instance`
update performance_schema.events_waits_summary_by_instance
set count_star=12 where event_name like "FOO";
ERROR 42000: UPDATE command denied to user 'root'@'localhost' for table `performance_schema`.`events_waits_summary_by_instance`
delete from performance_schema.events_waits_summary_by_instance
where count_star=1;
ERROR 42000: DELETE command denied to user 'root'@'localhost' for table `performance_schema`.`events_waits_summary_by_instance`
delete from performance_schema.events_waits_summary_by_instance;
ERROR 42000: DELETE command denied to user 'root'@'localhost' for table `performance_schema`.`events_waits_summary_by_instance`
LOCK TABLES performance_schema.events_waits_summary_by_instance READ;
ERROR 42000: SELECT, LOCK TABLES command denied to user 'root'@'localhost' for table `performance_schema`.`events_waits_summary_by_instance`
UNLOCK TABLES;
LOCK TABLES performance_schema.events_waits_summary_by_instance WRITE;
ERROR 42000: SELECT, LOCK TABLES command denied to user 'root'@'localhost' for table `performance_schema`.`events_waits_summary_by_instance`
UNLOCK TABLES;
#
# MDEV-25325 column_comment for performance_schema tables
#
select column_name, column_comment 
from information_schema.columns 
where table_schema='performance_schema' and table_name='events_waits_summary_by_instance';
column_name	column_comment
EVENT_NAME	Event name. Used together with OBJECT_INSTANCE_BEGIN for grouping events.
OBJECT_INSTANCE_BEGIN	If an instrument creates multiple instances, each instance has a unique OBJECT_INSTANCE_BEGIN value to allow for grouping by instance.
COUNT_STAR	Number of summarized events
SUM_TIMER_WAIT	Total wait time of the summarized events that are timed.
MIN_TIMER_WAIT	Minimum wait time of the summarized events that are timed.
AVG_TIMER_WAIT	Average wait time of the summarized events that are timed.
MAX_TIMER_WAIT	Maximum wait time of the summarized events that are timed.