How to enable Query Latency Trend report for Sharepoint 2010

Sharepoint Server 2010 has contains builting Search administration reports. You can find them via
Central Administration -> Administrative Report Library -> Search Administration reports.

One of the reports that is very useful is the Query Latency Trend chart. This does not work out of the box because verbose query monitoring is disabled.

To enable the Query Latency Trend report, you must run the following Windows PowerShell cmdlets:

$app = Get-SPEnterpriseSearchServiceApplication “<application name>”
$app = Set-SPEnterpriseSearchServiceApplication -VerboseQueryMonitoring “True”
$app = Get-SPEnterpriseSearchServiceApplication “<application name>”
$app.Update()

Example:

$sar = Get-SPEnterpriseSearchServiceApplication
$sar.VerboseQueryMonitoring = $true
$sar.Update()
Resource:
http://technet.microsoft.com/en-us/library/ee808861.aspx