Live registration reopens October 1, 2026, in 12d 16h 23mNotify me

Free SQL Server help, 3× a week

Your databases are slow. My emails will fix that.

Three blog posts a week, plus a Monday roundup of my favorite database news from around the web. No fluff, occasional jokes.

Or start with the free First Responder Kit

Cartoon Brent Ozar holding a coffee mug

Recorded classes

The latest recordings are on sale now

The Fundamentals of Index Tuning, Query Tuning, and Server Tuning have all been updated as of July 2026, reflecting the latest advancements in the First Responder Kit, AI, and SQL Server 2025. They're perfect for folks who have never been to a formal training class, but are responsible for performance on SQL Server, Azure SQL DB, and Amazon RDS.

Browse the classes

Live classes

The next live rotation is coming

Get first dibs (and the early-bird price) the moment registration opens.

Need hands-on help? SQL Critical Care® — my 2-day server assessment that finds the root cause and hands you the fix.

See consulting

Fresh from the blog

All posts
Performance Tuning

“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.

Today's misconception comes from a LinkedIn commenter telling me it's safe to use if you're doing index seeks. Hoo boy. Let's whip up a table with an index:

Read more about “But NOLOCK won’t hurt me if I’m using an index!” 15 comments — Join the discussion