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MSSQL 2008: Collect Buffer Cache Hit Ratio

Microsoft.SQLServer.2008.BufferCacheHitRatio (Rule)

Collects the Windows "Buffer Cache Hit Ratio" performance counter for each instance of SQL 2008 DB Engine.

Knowledge Base article:

Summary

Percentage of pages found in the buffer cache without having to read from disk. The ratio is the total number of cache hits divided by the total number of cache lookups over the last few thousand page accesses. After a long period of time, the ratio moves very little. As far as reading from the cache is much less expensive than reading from the disk, you want this ratio to be high. Generally, you can increase the buffer cache hit ratio by increasing the amount of memory available to SQL Server.

Overrideable Parameters

Name

Description

Default Value

Enabled

Enables or disables the workflow.

Yes

Frequency (seconds)

The recurring interval of time in seconds in which to run the workflow.

900

Element properties:

TargetMicrosoft.SQLServer.2008.DBEngine
CategoryPerformanceCollection
EnabledTrue
Instance Name$Target/Property[Type="SQL!Microsoft.SQLServer.DBEngine"]/PerformanceCounterObject$:Buffer Manager
Counter NameBuffer cache hit ratio
Frequency900
Alert GenerateFalse
RemotableTrue

Member Modules:

ID Module Type TypeId RunAs 
DS DataSource System.Performance.DataProvider Microsoft.SQLServer.SQLDefaultAccount
PerfMapper ConditionDetection System.Performance.DataGenericMapper Default
WriteToDB WriteAction Microsoft.SystemCenter.CollectPerformanceData Default
WriteToDW WriteAction Microsoft.SystemCenter.DataWarehouse.PublishPerformanceData Default

Source Code:

<Rule ID="Microsoft.SQLServer.2008.BufferCacheHitRatio" Enabled="true" Target="SQL2008Core!Microsoft.SQLServer.2008.DBEngine">

  <Category>PerformanceCollection</Category>

  <DataSources>

    <DataSource ID="DS" TypeID="SystemPerf!System.Performance.DataProvider" RunAs="SQL!Microsoft.SQLServer.SQLDefaultAccount">

      <ComputerName>$Target/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/NetworkName$</ComputerName>

      <CounterName>Buffer cache hit ratio</CounterName>

      <ObjectName>$Target/Property[Type="SQL!Microsoft.SQLServer.DBEngine"]/PerformanceCounterObject$:Buffer Manager</ObjectName>

      <InstanceName/>

      <AllInstances>false</AllInstances>

      <Frequency>900</Frequency>

    </DataSource>

  </DataSources>

  <ConditionDetection ID="PerfMapper" TypeID="SystemPerf!System.Performance.DataGenericMapper">

    <ObjectName>SQL DB Engine:Buffer Manager</ObjectName>

    <CounterName>$Data/CounterName$</CounterName>

    <InstanceName/>

    <Value>$Data/Value$</Value>

  </ConditionDetection>

  <WriteActions>

    <WriteAction ID="WriteToDB" TypeID="SC!Microsoft.SystemCenter.CollectPerformanceData"/>

    <WriteAction ID="WriteToDW" TypeID="SCDW!Microsoft.SystemCenter.DataWarehouse.PublishPerformanceData"/>

  </WriteActions>

</Rule>