A database query times out and you don’t know why. The estimated query plan is revealing the problem, so you remove the timeout entirely. An hour later it is still running and you are no closer to getting the actual execution plan. If only there was a way to find out what is actually happening inside the server.
With Live Query Statistics in SQL Server 2016 you can now answer that question. This new feature offers the DBA a live version of the execution plan with annotations detailing which steps are currently being performed.
read more at http://www.infoq.com/news/2015/07/Live-Query-Stats