Short answer: the SQL Server optimizer will know that the table was truncated, but statistics might not update when you expect.
For the long answer, let’s walk through an example using the WideWorldImporters sample database.
Whether I’m working as a DBA, a consultant, a teacher, or just answering questions in my inbox, I always end up needing a script to inspect statistics one way or another.
Here are some freshly written scripts for a classic DBA question: what’s going on in my stats?
Want to learn to tune indexes in SQL Server? I’ll be teaching a day-long pre-conference session in Portugal in March. Hope to see you there, or at SQL Saturday Lisbon (free!) the following weekend.
You’ve got an important stored procedure that you think needs index help– but it runs in environment with lots of other queries. How do you focus in and discover exactly what indexes need tuning for that procedure?
Today’s question is about why a query might be slow at first, then fast the next time you run it.
I’ve gotten a few questions about shrinking SQL Server data files lately. What’s the best way to get shrink to run? And why might it fail in some cases?
Traditionally, every time you ask a DBA how to make shrinking suck less, they start ranting how shrinking is bad and you just shouldn’t do it. Sometimes it sounds kinda angry.
What people are trying to say is that shrinking data files is generally slow, frustrating, and painful for you.
Episode update, April 2017: Learn About Adaptive Query Processing from Joe Sack
Microsoft shared a great video about Adaptive Query Processing, and you can learn about this new feature from Microsoft Program Manager Joe Sack. My original post below is full of speculation. Joe’s video is full of actual facts!
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