Detained
Despite the many metric tons of blog posts warning people about this stuff, I still see many local variables and optimize for unknown hints. As a solution to parameter sniffing, it’s probably the best choice 1/1000th of the time. …
Category: Plan Cache
A Query To Help You Find Plans With Eager Index Spools
Yawn And Yawn
I’ve written a bunch about Eager Index Spools, and how to fix them, but I’ve always sort of left the “finding” part up to you, or pointed curious tuners to tools like sp_BlitzCache.
Recently though, …
Documentation for dm_db_missing_index_group_stats_query
No, It’s New
When I was checking out early builds of SQL Server 2019, I noticed a new DMV called dm_db_missing_index_group_stats_query, that I thought was pretty cool.
It helped you tie missing index requests to the queries that requested …
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 The 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 …
What’s The Point Of Estimated Plans, Anyway?
Further From Truth
Estimated plans can be a bit confounding, huh?
Whether you see one by hitting CTRL+L, looking in the plan cache, or looking in Query Store, the song remains the same.
The query is slow: sometimes? always? usually? …
Whose Plan Handle Is It Anyway?
End Of The Line
There are a lot of words you can use to describe Extended Events. I’ll skip over my list to keep the blog family friendly.
In this post, we’re going to look at how two event can …
Is RECOMPILE Really That Bad?
To Re Or Not To Re
It’s been a while since SQL Server has had a real RECOMPILE problem. And if you put it up against the performance problems that you can hit with parameter sniffing, I’d have a …
Are Long Compile Times Bringing You Down?
Rarities
I ran into a very funny situation while working with a client recently. They were using Entity Framework, and a query with around 10 left joins ended up with a compile time of nearly 70 seconds.
Once the query …