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?
Does your team know what it’s doing with SQL Server?
Learn what a consultant looks for when assessing a team, and signs that SQL Server may be badly configured.
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 recently got a fantastic question from a reader regarding lock usage in SQL Server:
One of my production databases has a total lock count around 25,000 (select count(*) from sys.dm_tran_locks). The configuration setting for locks is set to the default of zero. This lock count is due to multiple procedures which frequently run and use the same 2-3 tables, repeatedly taking out and releasing locks. Do I need to change the configuration for locks or look into the SP’s so they can finish more quickly, rather than creating locks?
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