SQLServerFast

SQL injection, and how to prevent it

Hugo Kornelis — Mon, 16 Mar 2026 19:34:09 +0000

For a change, a video about security, rather than performance and execution plans. Why? Well, that should become clear in my next planned videos. Although I really can’t predict when I’ll be able to record those. What is it? And how to prevent it? In the first approximately 12.5 minutes of the video, I try...

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Back in hospital

Hugo Kornelis — Sun, 15 Mar 2026 18:59:00 +0000

(Warning: This blog post is non-technical but purely personal. I write openly about my current health issues. This blog might be triggering for people who struggle with, or lost dear ones to, cancer and other similar diseases.) Time for an update in my leukemia diary. I had planned to write as soon as I was...

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Return to the diary

Hugo Kornelis — Thu, 05 Mar 2026 17:50:46 +0000

(Warning: This blog post is non-technical but purely personal. I write openly about my current health issues. This blog might be triggering for people who struggle with, or lost dear ones to, cancer and other similar diseases.) In September 2022, I was diagnosed with leukemia. I was treated with chemotherapy, I received a stem cell...

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Optimized Locking part 2: Lock After Qualification

Hugo Kornelis — Thu, 26 Feb 2026 15:52:32 +0000

SQL Server 2025 introduced Optimized Locking. Not one, but two features, sharing a single marketing name. Lock After Qualification (LAQ) One of these two features is Lock After Qualification (LAQ). This feature avoids the scenario where a delete or update is blocked by a locked row that would not qualify. But, like any good thing,...

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Video training update

Hugo Kornelis — Sun, 22 Feb 2026 15:05:23 +0000

My training videos in the SQLServerFast Execution Plan Video Training are never just a done deal. Whenever there is new information to share, either because Microsoft adds new functionality, or because I discover something I did not know before, I go back and add this new information to the appropriate videos. Any such update always...

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Precon, precon, precon

Hugo Kornelis — Sun, 15 Feb 2026 13:00:16 +0000

If you read this blog, then it is very likely that you have an interest in execution plans. And that you want to increase your understanding of execution plans. A great way to really get to the next level is to attend a precon about execution plans, to get a full day of training on...

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Storage structures 3 – Memory-optimized

Hugo Kornelis — Fri, 13 Feb 2026 17:35:28 +0000

Update February 26: The maximum of 8 memory-optimized indexes per table was dropped in SQL Server 2017. After discussing traditional on-disk rowstore storage in part 1 and columnstores in part 2, it is now time to turn our eye towards memory-optimized storage structures in SQL Server. Memory-optimized storage was introduced in SQL Server 2014, as...

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Optimized Locking part 1: Transaction ID Locking

Hugo Kornelis — Thu, 12 Feb 2026 15:56:32 +0000

SQL Server 2025 introduced Optimized Locking. Not one, but two features, sharing a single marketing name. Transaction ID (TID) Locking One of these two features is Transaction ID (TID) Locking. Slated to end the memory waste of thousands of individual row locks, and the concurrency killer of lock escalation. What it is, how does it...

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T-SQL Tuesday 195 – Code that aged well

Hugo Kornelis — Tue, 10 Feb 2026 13:16:56 +0000

It’s the second Tuesday of the month again. Time for T-SQL Tuesday, edition 195. This edition is hosted by Pat Wright, who wants to know whether our code aged well. The timing of that question could not have been any better for me, because I am right now working on an assignment related to a...

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Rowgoals, part 3: When rowgoals backfire

Hugo Kornelis — Mon, 02 Feb 2026 11:14:53 +0000

In part 1 of this mini-series, I explained what a rowgoal is and how it works to optimize a query with a TOP or FETCH expression. Part 2 then showed a few less obvious other cases where the optimizer might introduce rowgoals. In all cases so far, those rowgoals were beneficial. They helped the optimizer...

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