Symptoms
Assume that you use Microsoft SQL Server 2014. When you query about Dynamic Management Views (DMV) sys.dm_exec_requests in Microsoft SQL Server Management Studio (SSMS) by using Select * From sys.dm_exec_requests, you find that the values of column query_hash and query_plan_hash are NULL.
Resolution
The issue was first fixed in the following cumulative update of SQL Server.
Cumulative Update 1 for SQL Server 2014 /en-us/help/2931693
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
