Parallel query worker thread was involved in a deadlock

Question

I run an SQL Server Trace to track some deadlocks issues and I was hit on the head with this comment Parallel query worker thread was involved in a deadlock as

Answer 1

Take a look at Understanding and Using Parallelism in SQL Server

You also want to take a look at using MAXDOP as a query hint

Sometimes all you need is an index, see Fix Execution Plan showing Parallelism