A picture showing a hiking path in a forest.

Home for now

(Warning: This blog post is non-technical but purely personal. In my leukemia diary, 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 my previous post, I wrote about the ups and downs as I was told I could go home as outpatient, and then developed a fever and had to return to the hospital. Luckily, that situation changed shortly after I published that post. Back home (and now for real) As I wrote in my last blog, after feeling rather…
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Insane rollercoaster design from the game Rollercoaster Tycoon

Ups and downs

(Warning: This blog post is non-technical but purely personal. In my leukemia diary, 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.) I planned to write this on Saturday, March 28. But I didn’t. It’s already Tuesday, March 31 by now, and I finally started writing. There is a reason for that, and I’ll get to it. But, let’s first start with the post I wanted to write, the post I already had drafted in my head, on Saturday. That post…
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To be where I need to be

(Warning: This blog post is non-technical but purely personal. In my leukemia diary, 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.) As I write this (Monday 19:00 in Utrecht – I might finish and post it later), I want to be somewhere else. Right at this time, the MVP Summit has just started. Official sessions usually run Tuesday to Thursday, but past years often saw extra sessions on the Monday before or the Friday after. Smaller sessions. Informal. Direct contact…
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SQL injection, and how to prevent it

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 to explain the concept of what SQL injection is in the most simple and non-technical terms I could come up with. But I also show, in that analogy, what defensive measures do and do not work. And how easy it ultimately is to be safe.…
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Back in hospital

(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 admitted to the hospital. I changed that plan a bit, for reasons I’ll get into later. But I am in hospital now, for a few days already. Awkward communication The last thing I had heard from my hematologist when I wrote the previous blog was…
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Return to the diary

(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 infusion, and then, after a long recovery period, I was clean and I could return to life before I got ill. I wrote about that extensively, in what I called my leukemia diary. The only thing in my life that still reminded me of my…
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Optimized Locking part 2: Lock After Qualification

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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, there is a price. This video shows the feature, explains how it works, and shows some of the potentially undesired side effects. More of me? Was this useful to you? Do you want to learn more from me? You can click here to see an…
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Video training update

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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 comes free of charge to those who bought access to the videos. Once you have access, you can watch these videos as often as you like. And you will always see the latest and greatest version! So it makes sense to stay updated on those…
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Photo of Hugo Kornelis presenting at a conference

Precon, precon, precon

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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 this topic. Another option is to purchase access to the SQLServerFast Execution Plan Video Training, currently over 20 hours of video with very extensive and in-depth training on execution plans. The best option is of course to combined the two: attend a precon, and get…
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Storage structures 3 – Memory-optimized

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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 part of a project that was codenamed “Hekaton” and later renamed to in-memory OLTP. Whereas columnstore indexes were specifically targeted towards large scale analytical work, Hekaton and memory-optimized tables are specifically geared towards high volume OLTP workloads. By fully eliminating locks and latches, and using…
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