SQL Server, Analytics, .Net, Machine Learning, R, Python
Mitch Wheat has been working as a professional programmer since 1984, graduating with a honours degree in Mathematics from Warwick University, UK in 1986. He moved to Perth in 1995, having worked in software houses in London and Rotterdam. He has worked in the areas of mining, electronics, research, defence, financial, GIS, telecommunications, engineering, and information management. Mitch has worked mainly with Microsoft technologies (since Windows version 3.0) but has also used UNIX. He holds the following Microsoft certifications: MCPD (Web and Windows) using C# and SQL Server MCITP (Admin and Developer). His preferred development environment is C#, .Net Framework and SQL Server. Mitch has worked as an independent consultant for the last 10 years, and is currently involved with helping teams improve their Software Development Life Cycle. His areas of special interest lie in performance tuning
Wednesday, October 04, 2017
SQL Server: Do You Have a Poorly Performing Query you can't Explain?
If you are running a SQL Server version prior to SQL Server 2016, and you have a query whose plan just doesn't seem right and you can't explain it, try running it with trace flag 4199
It enables all the query optimiser hot fixes present in your applied SP and CU version.
Many DBAs enable this trace flag globally (at the instance level).
SQL Server 2016 will automatically enable all prior version query optimiser hot fixes.
SQL Server query optimizer hotfix trace flag 4199 servicing model
SQL Server 2016: The Death of the Trace Flag
MSN, Email: mitch døt wheat at gmail.com