There’s a lot going on there, but much of it is noise. There is a whole bunch of contention on the table
SqlPerf.Session— session 342 is trying to perform an update, but it is stuck waiting on shared locks taken by two services. Now, let’s check the Optimize Layout box above, and look at the circular graph again. Simplified, right?
This checkbox is easily the most powerful option to discard noise and help you focus on the crux of the deadlock issue. In the original graph, you can see that many of the elements presented are simply innocent bystanders — waiters that are captured as part of the deadlock activity, but in no way contributing to it. We can detect this in a lot of cases and so, when you check the box, we hide them from view, allowing you to focus much more directly on the key players involved in the deadlock. There is no question that eliminating the noise can really speed up troubleshooting; with those extra nodes removed, I can clearly see that I have some kind of order-of-operations issue on the
SqlPerf.Sessiontable, between the transfer service and the processor service.