Jonathan Kehayias is a Principal Consultant with SQLskills. He is the youngest person ever to achieve the Microsoft Certified Master - SQL Server 2008 certification and has been a SQL Server MVP for many years. Click here for a full bio.
Jonathan Kehayias (@SQLPoolBoy) demonstrates column-side implicit conversions and the impact they can have on a workload. He concludes that you can only throw hardware at this problem for so long; a design or code change will be necessary to solve the performance issue long-term.
Jonathan Kehayias (@SQLPoolBoy) of SQLskills.com evaluates the performance impact of query_post_execution_showplan and explains why you need to be very careful about using it in a production environment.
Numerous licensing changes were introduced in SQL Server 2012; the most significant was the move from socket-based licensing to core-based licensing for Enterprise Edition. One of the challenges that Microsoft faced with this change was providing a migration path for customers that previously used Server+CAL based licensing for Enterprise Edition prior to SQL Server 2012. Customers under Software Assurance can upgrade to SQL Server 2012 Enterprise Edition and still use Server+CAL licensing (also known as "grandfathering") but with a limitation to 20 logical processors, as documented in the SQL Server 2012 Licensing Guide.
SQL Server offers two methods of collecting diagnostic and troubleshooting data about the workload executed against the server: SQL Trace and Extended Events. Starting in SQL Server 2012, the Extended Events implementation provides comparable data collection capabilities to SQL Trace and can be used for comparisons of the overhead incurred by these two features. In this article we'll take a look at comparing the "observer overhead" that occurs when using SQL Trace and Extended Events in various configurations in order to determine the performance impact that data collection may have on our workload through the use of a replay workload capture and Distributed Replay.