The SQL Server Date Magic: When CAST and CONVERT Keep Your Index Seek

This article shows two scenarios, tested independently, with the full scripts and the real numbers from each run.

“But NOLOCK won’t hurt me if I’m using an index!”

NOLOCK is bad and you probably shouldn't use it, but every time I mention that publicly, the pushback just keeps coming. I don't know why people so firmly believe that their situation couldn't possibly be affected by bad/random data from NOLOCK.

Database Animations: Stop Using Page Splits to Justify Lowering Fill Factor.

You're looking at page split numbers in a monitoring tool or Perfmon, and you've heard that page splits are bad, so you're lowering fill factor, expecting your page splits to go down.

Parameter Sniffing on SQL Server 2025: A Walkthrough with Real Numbers

This article looks at how the parameter sniffing performance problem can be helped in SQL Server 2025 with PSPO.

Database Animations: What’s a Residual Predicate and Why Is It Bad?

Normally when you're looking at an execution plan, and you see an index seek followed by a key lookup, that means it's running relatively quickly.

Optional Parameter Plan Optimization in SQL Server 2025: Fixing the Kitchen-Sink Search Procedure

See how SQL Server 2025 uses Optional Parameter Plan Optimization to create separate plans for selective and unfiltered searches, how to verify the dispatcher and variants, and when dynamic SQL or recompilation is still the better choice.

Tracking All the Queries

Advanced T-SQL: Replacing Slow Cursors with Window Functions

This article looks at replacing a cursor with a window function to improve performance.

Database Animations: You’ve Heard of Page Splits. Here’s What They Really Mean.

You've heard that page splits are bad, and they're an indication that your table design is making your storage work too hard. You've heard that the right answer to fix it is adjusting fill factor lower, or doing regular index maintenance.

Finding Bad Queries

Recognizing queries that might perform poorly is a skill that will help you, and your AI assistant, produce better code in production.