select * from performance_schema.metadata_locks;
select * from performance_schema.metadata_locks
where object_name='foo';
OBJECT_TYPE	OBJECT_SCHEMA	OBJECT_NAME	OBJECT_INSTANCE_BEGIN	LOCK_TYPE	LOCK_DURATION	LOCK_STATUS	SOURCE	OWNER_THREAD_ID	OWNER_EVENT_ID
insert into performance_schema.metadata_locks
set object_name='FOO', owner_thread_id=1;
ERROR 42000: INSERT command denied to user 'root'@'localhost' for table 'metadata_locks'
update performance_schema.metadata_locks
set owner_thread_id=12 where object_name='foo';
ERROR 42000: UPDATE command denied to user 'root'@'localhost' for table 'metadata_locks'
delete from performance_schema.metadata_locks;
ERROR 42000: DELETE command denied to user 'root'@'localhost' for table 'metadata_locks'
delete from performance_schema.metadata_locks
where timer_name='CYCLE';
ERROR 42000: DELETE command denied to user 'root'@'localhost' for table 'metadata_locks'
LOCK TABLES performance_schema.metadata_locks READ;
ERROR 42000: SELECT, LOCK TABLES command denied to user 'root'@'localhost' for table 'metadata_locks'
UNLOCK TABLES;
LOCK TABLES performance_schema.metadata_locks WRITE;
ERROR 42000: SELECT, LOCK TABLES command denied to user 'root'@'localhost' for table 'metadata_locks'
UNLOCK TABLES;