Scary Scalar Functions - Part Two: Performance

Scary Scalar Functions series overview

Part One: Parallelism
Part Two: Performance

Foreword
In the second part of this series, we’ll look at how Scalar functions (or UDFs) affect performance.
If you want to follow...

What is causing my constraint to be untrusted?

The problem
In this scenario, you have discovered that one of your Check constraints or Foreign keys is not trusted.
Maybe you’ve detected it with a sp_Blitz, dbachecks or out of...

Scary Scalar Functions - Part One: Parallelism

Foreword
I’m still surprised many people don’t realise how lousy Scalar functions (aka User Defined Functions aka UDFs) are. So because it’s my current focus in work and this Stack...

Coding Standards (T-SQL Tuesday #151)

Foreword
This month’s invitation is from Mala Mahadevan, and it’s about coding standards. Fortunately, I may forget several basic ones because my team probably eradicated them long ago.
I’ll go with...

New Extended Events in SQL Server 2022

SQL Server 2022 CTP is here
It has been announced today (2022-05-24) during the MS Build event. The blog post includes a download link. Unfortunately, the Docker container is...

Efficient Cheating at Lego Video Games

Foreword
I’ve started to play Lego Video games with my daughter, and since it’s one of her first games, it can be a little frustrating.
Even though there are no high...

Cross DB Access With Module Signing

Foreword
I’ve recently had to revisit this topic and spent a lot of time recalling the details. So I’m writing this blog post mainly as a reminder for myself.
The most...

Why my way of writing SQL is superior

⚠️ It’s hard to convey sarcasm over the text. I’m putting this disclaimer at the top so I don’t come off egoistic. This post is meant as hyperbole, and...

Query Hash and Query Plan Hash Mapping

The problem
As a fan of Dynamic Management Objects (DMOs), Query Store and Extended Events, I often work with the Query Hash and Query Plan Hash (I’ll refer to them...

KEEP PLAN Demystified

Foreword
I was always wondering what the KEEP PLAN hint does. The documentation isn’t very specific (emphasis mine):

Forces the Query Optimizer to relax the estimated recompile threshold for a query.

In...