I am SQL Server Performance Tuning Expert at @SQLAuthority
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SQL Server is changing.
AI is changing how we work with databases.
I spend my time exploring where the two meet.
Here you will find:
SQL Server performance tuning
Query tuning and troubleshooting
Practical AI ideas for DBAs
Real-world scripts and demos
Lessons from actual performance problems
No hype. No fluff.
Just practical learning around SQL Server, performance, and AI.
Follow if that is your kind of content.
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Two query lines are on the page. One looks longer. Look once, make a choice, and then look again.
I have spent years looking at execution plans. The lines, boxes and arrows can make an expensive operation look important before I have read a single number. That is useful when the picture points me to a place worth investigating. It is less useful when I start treating the size of a drawing as evidence.
For today's Sunday puzzle, look at the two dark horizontal lines in the picture. The upper one sits near the narrow end of a server aisle. The lower one sits near the wide end. Do not measure them yet. Which line looks longer to you? If someone else is nearby, ask them before you scroll. It is more fun when two people are confidently wrong in different directions.
The illustration was drawn to a fixed grid. There is no animation and nothing changes when you look away. Give your eyes five seconds, then read the answer.
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My 18th & 19th books are here!
I never expected “100 AI Interview Questions” to receive so much love. It’s on track to outsell “AI: Nobody’s in There.”
Seems this was what people needed. Thank you ❤️
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The author copies of my 18th and 19th books have arrived.
Nineteen books, and this part still makes me pause. Seeing your words on a screen is one thing. Holding the printed pages is another.
These two books explore questions I care about.
📖 AI: Nobody’s in There. But we’re still in here.
Thirty short essays about AI, work, learning, and the human judgment we still need. For anyone trying to understand how this change feels, alongside what it does.
The story behind the book:
blog.sqlauthority.com/2026/0…
📖 100 AI Interview Questions and Answers for Data Professionals
A practical book with 100 questions, 184 key terms, and short answers you can practice aloud. For data professionals who want to explain what they know clearly when the conversation turns to AI.
The announcement includes questions you can try:
blog.sqlauthority.com/2026/0…
Today, I wanted to share the photograph and say thank you. If you have read my work, asked a thoughtful question, or pointed out something I missed, you have helped make the writing better.
Which one would you open first?
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I honestly don’t know how to react.
So many of you have bought my AI Interview Questions book, and quite a few have even asked me to send them the PDF so they can share it freely with friends.
Part of me smiles at that. Part of me doesn’t know what to say. 😊
But I do want to say this:
This is not just another AI book I put together quickly.
I spent a lot of time, thought, research, rewriting, and effort on it. I genuinely tried to create something useful, practical, and worth your time.
So seeing people interested in it, buying it, talking about it, and wanting to share it means more to me than I can properly express.
Thank you for all the love. ❤️
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[Just released my 19th book]
100 AI Interview Questions and Answers for Data Professionals: From Keywords to Concepts
AI has walked into every data interview. A vague answer can cost you the offer.
This book gives you the 100 AI questions data interviewers ask, with plain answers you can say out loud in about thirty seconds. Each answer shows why it matters at work, what the interviewer is listening for and the trap that catches people.
It's written for every data professional: DBAs, data engineers, analysts, developers and architects, on any database and with any AI tool.
I have spent a lot of time building this book and I am very much looking forward to your opinions.
The books is available in three format: Print, Kindle eBook and Audio Book.
Link in the first comment. I am very much interested in your feedback about this book.
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I just published my 19th book - it is about 100 AI Interview Questions and Answers for Data Professionals: From Keywords to Concepts
Let me know if you are interested, I will share the link.
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NOLOCK double counting is the bug where three people stand in a lunch line and four lunches go out. Nobody new showed up. One person went through twice.
That’s this week’s episode of SQL in Sixty Seconds. Dex counts lunch tickets for Owen, June and Sam, and the total comes to four. Mia spots the problem in two seconds. Owen got back in line, and Owen’s excuse is that the second lunch is for later.
Watch it here: blog.sqlauthority.com/2026/0…
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The Migration of a Row: Tagged, Followed, Found Again
If you read nothing else, read this. I tagged one row, followed it to the grave, and then went looking for the body.
The log gets there first. Before the commit, the insert already exists as a 284 byte log record. The data file hears about it later.
The row has a street address. (1:392:0) is file one, page 392, slot zero. It is 184 bytes on a page of 8,192.
Delete does not erase. The record stays exactly 184 bytes. One flag turns it into a ghost, and the table stops counting it.
Here is the part nobody expects. The table is empty and the ghost has been swept away. The database still knows the traveller’s name, because it is sitting in a statistics histogram. DatabasePerformance Check
Why your data is in a histogram at all. Every database guesses before it works. It keeps a cheat sheet of real values, so it can estimate how many rows a query will touch.
You can clear it, almost. One command rewrites that cheat sheet from what is there now, which is nothing. The old pages are marked unused rather than wiped, so the name still rides along in tonight’s backup.
The rest of this is the same story, with the screenshots and the measurements. The queries are all here, so you can run it on your own server.
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The Navier-Stokes problem starts with a cup of tea. Stir it, pull out the spoon, and watch the swirl slowly settle. The math that describes that swirl is about two hundred years old. For about ninety years, nobody could answer one question about it.
The Navier-Stokes equations describe how fluids move. Water in a pipe, air over a wing, tea in a cup. Engineers use them to design airplanes and cars, and weather forecasts lean on them too. They even account for viscosity, the thickness that makes honey pour slower than water.
Read: blog.sqlauthority.com/2026/0…
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Your index rebuild maintenance plan runs every Sunday night, takes four hours, fills your transaction log, delays your backup, and may be buying you a great deal less than everybody assumes.
I am not going to tell you to turn it off blindly. I am going to tell you what it is actually doing, so you can measure whether it deserves those four hours.
Fragmentation is bad, so we defragment. It sounds obviously correct, and for a long time it mostly was.
That belief was built in the era of spinning disks. Reading pages that sat next to each other was dramatically faster than reading pages scattered across a platter, because a physical arm had to move.
On flash-backed storage, the penalty for scattered reads can be much smaller. If the pages are already in the buffer pool, SQL Server need not fetch them from storage at all. Page density still matters: half-empty pages take up memory too.
Read more here: blog.sqlauthority.com/2026/0…
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With less clutter does my website looks faster? blog.sqlauthority.com/ I am curious about your opinion?
After almost 20 years and 5,800+ posts, I finally did what I tell every client to do.
I cleaned up my own server.
SQLAuthority.com got a full spring cleaning this week. Here is the (long) list:
SPEED
• Found out the page cache was not caching a single page. One "/" in a setting excluded all of them. Oops. Fixed.
• Phone PageSpeed went from 88 to 95
• Accessibility, Best Practices and SEO: 100, 100, 100
• Theme CSS cut from 318 KB to 195 KB
• Fonts no longer make the page jump while it loads
• Header banner is sharper AND smaller (49 KB)
• A crawler is now pre-loading 5,884 pages, so the first visitor does not wait
• Heavy PNG pictures became WebP (526 KB to 71 KB)
IMAGES
• Every post now has a cover image. 1,618 of them were generated.
• About 10,000 images in posts now have real alt text
• Every picture in the Media Library now has alt text
• One image had an AI prompt as its alt text: "You are generating an HTML alt attribute..." Humans still needed.
• 34 alt texts that were literally "." or random numbers, fixed
• ~800 alt texts that were just file names ("selectstar") are being rewritten right now
• 1,675 unused files removed
• 6,844 old images moved into the Media Library, every old link still works
• 3 broken pictures found on a published post and fixed
PAGES
• Consulting, Training and Hire Me merged into one page with 4 clear options
• Health Check page rewritten
• Free Learning Videos page rebuilt
• Privacy Policy rewritten
• Phone menu now shows everything, with search
• Tags cut down to 283, and 8 clear categories
PLUGINS AND SECURITY
• 11 plugins retired
• Google Analytics now runs without a plugin
• My own firewall was blocking Bing's crawler. Unblocked.
• An old "trap" image had auto-banned 602 visitors, including Applebot. Removed.
No new features. No redesign. Just less junk.
The funny part? Nothing was broken enough to notice. Everything was slow enough to matter.
Performance tuning is not only for databases, it's for blogs too.
What is the one thing on your own system you keep meaning to clean up?
Check out : blog.sqlauthority.com
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I did not hand it a plan with a spill in it. Everybody can find a spill. I handed it a plan with no warnings at all, where every number on the screen looked healthy, and the query underneath was reading five million rows to return seventeen.
None of the mechanics here are new, and I have written about the two pieces this turns on before: SQL SERVER – Row Goal and Performance, which is why a TOP changes what the optimizer aims for, and SQL SERVER – Number of Rows Read, which is the plan property that gives it away. What is new here is that I said neither of those words to the AI, and I wanted to see how far it got on its own.
The Problem I Handed Over
Here is the exact thing I typed, before any plan, any context or any hint.
One stored procedure. One server. Statistics rebuilt this morning.Customer A has four million orders. Their screen loads instantly.Customer B has seventeen orders. Their screen is slow, every single time.The customer with fewer rows is the slow one. Why?
That is the whole ticket, and it is why nobody believed it for two weeks. It sounds like nonsense. More rows should mean more work.
This is the procedure. There is nothing clever in it.
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What next well you can read here: blog.sqlauthority.com/2026/0…
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After almost 20 years and 5,800+ posts, I finally did what I tell every client to do.
I cleaned up my own server.
SQLAuthority.com got a full spring cleaning this week. Here is the (long) list:
SPEED
• Found out the page cache was not caching a single page. One "/" in a setting excluded all of them. Oops. Fixed.
• Phone PageSpeed went from 88 to 95
• Accessibility, Best Practices and SEO: 100, 100, 100
• Theme CSS cut from 318 KB to 195 KB
• Fonts no longer make the page jump while it loads
• Header banner is sharper AND smaller (49 KB)
• A crawler is now pre-loading 5,884 pages, so the first visitor does not wait
• Heavy PNG pictures became WebP (526 KB to 71 KB)
IMAGES
• Every post now has a cover image. 1,618 of them were generated.
• About 10,000 images in posts now have real alt text
• Every picture in the Media Library now has alt text
• One image had an AI prompt as its alt text: "You are generating an HTML alt attribute..." Humans still needed.
• 34 alt texts that were literally "." or random numbers, fixed
• ~800 alt texts that were just file names ("selectstar") are being rewritten right now
• 1,675 unused files removed
• 6,844 old images moved into the Media Library, every old link still works
• 3 broken pictures found on a published post and fixed
PAGES
• Consulting, Training and Hire Me merged into one page with 4 clear options
• Health Check page rewritten
• Free Learning Videos page rebuilt
• Privacy Policy rewritten
• Phone menu now shows everything, with search
• Tags cut down to 283, and 8 clear categories
PLUGINS AND SECURITY
• 11 plugins retired
• Google Analytics now runs without a plugin
• My own firewall was blocking Bing's crawler. Unblocked.
• An old "trap" image had auto-banned 602 visitors, including Applebot. Removed.
No new features. No redesign. Just less junk.
The funny part? Nothing was broken enough to notice. Everything was slow enough to matter.
Performance tuning is not only for databases, it's for blogs too.
What is the one thing on your own system you keep meaning to clean up?
Check out : blog.sqlauthority.com
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