I want to calculate the page life expectancy of my SQL Server. If I query the PLE with the follwowing query I get the value 46.000:
SELECT [object_name],
[counter_name],
[cntr_value] FROM sys.dm_os_performance_counters
WHERE [object_name] LIKE '%Manager%'
AND [counter_name] = 'Page life expectancy'
I think this value isn't the final value because of the high amount. Do I have to calculate these value with a specifiy formula? Thanks
Although some counters reported by sys.dm_os_performance_counters are cumulative, PLE reflects the current value so no calculation is necessary.
As to whether the value of 46 seconds is a cause for concern depends much on the workload and storage system. This value would be concern on a high-volume OLTP system with local spinning disk media due to the multi-millisecond latency incurred for each physical IO and IOPS of roughly 200 per spindle. Conversely, the same workload with high-performance local SSD may be fine because the storage capable of well over 100K IOPS.