Posts

Parameter Sensitive Plan Optimization

May 23, 2026

Bad hair day? Try having an almost-no-hair month! Jokes aside. It has been almost six weeks since my last video blog. Not really the schedule I had planned. But I believe I have good reasons. Anyway, I do have a new video ready now. As promised in my last video, I now cover Parameter Sensitive Plan Optimization (PSPO), a new feature, introduced in SQL Server 2022, that is supposed to alleviate the pain of bad parameter sniffing. PSPO, the answer to bad parameter sniffing? The first part of the video explains the feature, and how it is intended to work.…

Back on track

May 19, 2026

Hugo Kornelis

(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.) My last leukemia diary entry ended with a large question mark. What will my hematologist tell me when I see her again? What treatment will she recommend? What happened? No idea! Do you know this scenario? A new prospect calls. You have never seen their database system yet. But they do expect you to give a coherent and relevant…

Between despair and hope

May 9, 2026

Hugo Kornelis

(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.) It’s been a while since I last blogged about my leukemia. A full month, to be exact. In the first three weeks of that month, nothing special happened. I was home. I felt good. I made sure to get my daily walk in, to rebuild my fitness (well, except that one day when it was 25°C [77°F], and I…

Request for help – video hosting

April 21, 2026

Hugo Kornelis

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I create a lot of videos for the SQL Server community. These come in three categories. Recordings of conference sessions. Sometimes made by myself, sometimes by the conference organization. Typically uploaded to YouTube by the one who made the recording. I have links to all recordings that I know of in my session list. These are free to watch, and they come as is. They were recorded during a live delivery, you simply see what is recorded. No editing. I do usually add captions when I record them myself, but when others recorded and uploaded them, they usually only come…

Bad parameter sniffing, what is it and what can you do about it

April 13, 2026

Hugo Kornelis

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Time for a new video blog. This time, the topic is bad parameter sniffing. And with 43 minutes, the video is a bit longer than what I normally shoot for. What is it? What can you do about it? The video starts with an explanation of two good features: parameter sniffing and plan caching. But those features can interact in an unwanted way, resulting in erratic bad performance. Now we have what I call “bad parameter sniffing”. Starting at approximately 8:30, I then describe the three most common root causes for bad parameter sniffing: equality filters on a column with…

A picture showing a hiking path in a forest.

Home for now

April 9, 2026

Hugo Kornelis

(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…

Insane rollercoaster design from the game Rollercoaster Tycoon

Ups and downs

March 31, 2026

Hugo Kornelis

(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…

To be where I need to be

March 23, 2026

Hugo Kornelis

(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…

SQL injection, and how to prevent it

March 16, 2026

Hugo Kornelis

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.…

Back in hospital

March 15, 2026

Hugo Kornelis

(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…

Posts

Parameter Sensitive Plan Optimization

Back on track

Between despair and hope

Request for help – video hosting

Bad parameter sniffing, what is it and what can you do about it

Home for now

Ups and downs

To be where I need to be

SQL injection, and how to prevent it

Back in hospital

Hugo Kornelis

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