show databases;
Database
information_schema
mtr
mysql
performance_schema
test
select count(*) from performance_schema.performance_timers;
count(*)
5
select count(*) from performance_schema.setup_consumers;
count(*)
12
select count(*) > 3 from performance_schema.setup_instruments;
count(*) > 3
1
select count(*) from performance_schema.setup_timers;
count(*)
4
show engine PERFORMANCE_SCHEMA status;
show status like "performance_schema%";
show variables where
`Variable_name` != "performance_schema_max_statement_classes" and
`Variable_name` like "performance_schema%";
Variable_name	Value
performance_schema	ON
performance_schema_accounts_size	100
performance_schema_digests_size	200
performance_schema_events_stages_history_long_size	1000
performance_schema_events_stages_history_size	10
performance_schema_events_statements_history_long_size	1000
performance_schema_events_statements_history_size	10
performance_schema_events_waits_history_long_size	10000
performance_schema_events_waits_history_size	10
performance_schema_hosts_size	100
performance_schema_max_cond_classes	80
performance_schema_max_cond_instances	1000
performance_schema_max_digest_length	1024
performance_schema_max_file_classes	50
performance_schema_max_file_handles	32768
performance_schema_max_file_instances	10000
performance_schema_max_mutex_classes	200
performance_schema_max_mutex_instances	5000
performance_schema_max_rwlock_classes	40
performance_schema_max_rwlock_instances	5000
performance_schema_max_socket_classes	10
performance_schema_max_socket_instances	1000
performance_schema_max_stage_classes	160
performance_schema_max_table_handles	1000
performance_schema_max_table_instances	500
performance_schema_max_thread_classes	50
performance_schema_max_thread_instances	200
performance_schema_session_connect_attrs_size	2048
performance_schema_setup_actors_size	100
performance_schema_setup_objects_size	100
performance_schema_users_size	100