Troubleshooting Plans: P1-Root Cause Analysis/Caching Probs

When you review a query plan, what do you look at first? You probably find the most-costly operation and then look to see if SQL Server “knew” what it was doing? Did it get the right estimate? Nope! OK, so it’s just what you thought – it’s the statistics. So, you update the statistics and it fixes the problem. Problem solved!

Or, was it? One of the most common “false positives” that people see is that updating statistics “fixes” a problem. In this first session, I’ll decipher your query plans: where to look, what to look for, and how to know the truth. Then, once we determined if something is really a caching problem or a statistics problem, we’ll look at actually solving the problem. Updating statistics is often not the right long-term the solution!