RESOURCE_SEMAPHORE_QUERY_COMPILE happens, in a nutshell, when SQL Server has allocated all the memory it’s willing to give out to compile query plans of a certain size and, throttles itself by making other queries wait to compile. For more details, …

Join Me At Data Platform Summit 2020!

The Road From Nowhere

This year, I’m teaching an 8 hour online workshop at Data Platform Summit, and I’d love it if you joined me.

Here’s what I’ll be teaching:

Class Title: The Beginner’s Guide To Advanced Performance Tuning

Why Microsoft Should Get Rid Of SQL Server’s Plan Cache And Use Query Store Instead

Used To Love Her

I used to think the plan cache was so cool.

  • You can find queries that aren’t good there
  • Plans are full of details (and XML)
  • Supporting DMVs give you extra insights about resource usage

But most …

How Functions Can Make Performance Tuning SQL Server Queries Harder


I’ve posted quite a bit about how cached plans can be misleading.

I’m gonna switch that up and talk about how an actual plan can be misleading, too.

In plans that include calling a muti-statement table valued function, no …