Search Engagements was causing NOLOCK exception on SQL Server
Symptoms
Sometime search Engagements was causing NOLOCK data page movement error on the SQL Server. During the busy period requests were timing out after 30 seconds and causing a 500 Error in the user interface
Reason
Configuration issue
Resolution
To resolve the NOLOCK data page movement error install Cumulative Update 3 and enable trace flag 4135 on the SQL Server. To resolve timeout errors changed timeout setting in Global.asa file to 600 seconds to match timeout settings at other places.

