Click here to monitor SSC
SQLServerCentral is supported by Red Gate Software Ltd.
 
Log in  ::  Register  ::  Not logged in
 
 
 
        
Home       Members    Calendar    Who's On


Add to briefcase

Buffer Cache hit ratio Expand / Collapse
Author
Message
Posted Wednesday, August 27, 2014 1:58 PM
SSC Veteran

SSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC Veteran

Group: General Forum Members
Last Login: Yesterday @ 4:13 PM
Points: 208, Visits: 169
Hi,

We are checking the Buffer cache hit ratio (as % using Buffer cache hit ratio / Buffer cache hit ratio base) sampling every 15 sec. This is nearly always 100% but there are occasional (1 in 10) values which give results way off the normal. The counter and base values have spikes resulting in percentages (eg 5% or 150%) which throw off our trend reporting. We would like to know what the actual base and raw counter values represent (eg. a count of the number of requests for pages in the buffer pool?) and why the base would intermittently differ so erratically from the raw count?
Thanks
Matthew
Post #1608018
Posted Wednesday, August 27, 2014 2:27 PM


SSC-Forever

SSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-ForeverSSC-Forever

Group: General Forum Members
Last Login: Today @ 3:30 AM
Points: 43,010, Visits: 36,169
Rather ignore that counter. It's useless. Even on a server that's under severe memory pressure it'll be sitting near 100%


Gail Shaw
Microsoft Certified Master: SQL Server 2008, MVP
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Post #1608031
Posted Tuesday, September 9, 2014 12:28 PM
Valued Member

Valued MemberValued MemberValued MemberValued MemberValued MemberValued MemberValued MemberValued Member

Group: General Forum Members
Last Login: Yesterday @ 1:01 PM
Points: 69, Visits: 69
Hello,

Gila already hit the direction you should take: useless metric and not what you are looking for.

To better explain the reasons why that metric isn't getting you what you think it is please review this awesome post: https://www.simple-talk.com/sql/database-administration/great-sql-server-debates-buffer-cache-hit-ratio/

I spent some time a few weeks ago on this very same task to look up this setting as well. Utilizing information on this post I was able to see actual Buffer Cache Hit Ratio values.

Hope that helps and good luck!

Regards,
Jeremy
Post #1611921
« Prev Topic | Next Topic »

Add to briefcase

Permissions Expand / Collapse