Everything You Know About Parallelism is Wrong

Brent Ozar

I hate to be the one to break it to you, but CXPACKET and CXCONSUMER are meaningless wait types. MAXDOP doesn’t mean maximum degree of parallelism. Just because you see a parallelism icon on a query plan doesn’t mean multiple CPU cores were used. Parallel plans aren’t always faster than single-threaded plans.

In this all-demo session, I’ll take a simple Stack Overflow query and shatter one myth after another, debunking everything you thought you knew about how SQL Server handles parallelism. You’ll walk out disappointed and ashamed, but better equipped to make good decisions about performance tuning forward.