Buffer cache hit ratio 수집

OS의 Perfmon에서 수집하고자 하는 SQL Server Buffer Cache hit ratio를 수집하고자 할때 사용됩니다.

SELECT (a.cntr_value * 1.0 / b.cntr_value) * 100.0 as BufferCacheHitRatio
FROM sys.dm_os_performance_counters  a
JOIN  (SELECT cntr_value,
		OBJECT_NAME 
	FROM sys.dm_os_performance_counters  
	WHERE counter_name = 'Buffer cache hit ratio base'
		AND OBJECT_NAME = 'SQLServer:Buffer Manager') b 
	ON  a.OBJECT_NAME = b.OBJECT_NAME
WHERE a.counter_name = 'Buffer cache hit ratio'
	AND a.OBJECT_NAME = 'SQLServer:Buffer Manager'