mssql buffer cache hit ratio
SELECT c1.cntr_value, c2.cntr_value,
case
when c2.cntr_value > 0 then c1.cntr_value * 100 / c2.cntr_value
else -1
end as cache_hit_ratio_pct
FROM sys.dm_os_performance_counters c1,
sys.dm_os_performance_counters c2
WHERE
c1.[object_name] LIKE '%Buffer Manager%' AND c1.[counter_name] = '
Buffer cache hit ratio'
and
c2.[object_name] LIKE '%Buffer Manager%' AND c2.[counter_name] = '
Buffer cache hit ratio base'