Dear Sql Dba

Are Bad Statistics Making My Query Slow?

Informações:

Sinopse

An important query is suddenly slow. Is it because statistics are out of date? This is tricky to figure out, and updating statistics right away can make troubleshooting even harder. Learn how to use query execution plans to get to the heart of the question and find out if stats are really your problem, or if it's something else. In this 35 minute episode: 00:39 SQL Server 2017 Announced 01:10 New video from Microsoft's Joe Sack demonstrating Adaptive Query Processing 03:05 This week's question: Are bad stats making my query slow? 05:26 Demo of finding plan in cache and analyzing stats begins 28:17 What to do when stats ARE the problem Code samples: https://gist.github.com/LitKnd/f07848d59cedc61fd057d12ab966f703 Links from the episode: SQL Server 2017 Adaptive Query Processing video by Joe Sack: https://www.youtube.com/watch?v=szTmo6rTUjM&feature=youtu.be Michael J Swart on finding Dark Matter Queries: http://michaeljswart.com/2017/04/finding-your-dark-queries/ Got a question for Dear SQL DBA? https://SQLW