wait statistics

select 	wait_type,
								case 
												when wait_type = 'PAGELATCH_NL' then 'Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.'
												when wait_type = 'PAGELATCH_KP' then 'Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Keep mode.'
												when wait_type = 'PAGELATCH_SH'	then 'Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Shared mode.'
												when wait_type = 'PAGELATCH_UP' then 'Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Update mode.'
												when wait_type = 'PAGELATCH_EX'	then 'Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Exclusive mode.'
												when wait_type = 'PAGELATCH_DT' then 'Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Destroy mode.'
												else 'unknown'
												end wait_type_desc,
								waiting_tasks_count,
								wait_time_ms,
								max_wait_time_ms,
								signal_wait_time_ms
  from 	sys.dm_os_wait_stats
  where wait_type like 'PAGELATCH%'