What is SQL Server parameter sniffing and data skew?

How do I fix this?

If you found this page you most likely either found yourself in the middle of a SQL Server parameter sniffing and/or data skew issue and have no idea how to get yourself out of this hole. In the eight-minute video below we go over exactly what parameter sniffing and data skew is and how you can identify it on your own.

SPOILER ALERT: Parameter sniffing is mostly an amazing thing that saves tons of CPU cycles. Like many DBA tasks, this usually only gets attention when expectations are not met. Most likely you have these issues in your database without even knowing it. See a real-world case where data skew was resolved with a customer using SQL Server 2017 without changing any code.

How do we fix SQL Server parameter sniffing?

Now that you know what parameter sniffing and data skew is our next blog post will go over using Query Store and Automatic Tuning to enhance your performance automatically or manually. This will resolve queries that regressed due to parameter sniffing.

What Are Others Say about Parameter Sniffing?

Here are some classic posts from Microsoft on Parameter Sniffing (PFE blog at Microsoft. What is Parameter Sniffing )

Here is a great article from our partners at SentryOne.