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Game over

October 27, 2026

(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 have to write this blog, I have been putting it off for too long now. The past days, I kept finding excuses not to write it just yet. But I’m out of excuses now. I need to write this. A week ago, October 19, I went to hospital again. One of many visits, except for two things. One…

Done, but never finished

October 23, 2026

Hugo Kornelis

You can accuse me of many things. Lack of ambition is not on that list, though. Nor is speed of execution. In 2017, I made the decision that SQL Server execution plans needed better documentation. I did not expect Microsoft to do this for me. And so I decided, heavily inspired by Paul Randall’s Wait Type Library, to write it myself. I purchased the domain sqlserverfast.com, migrated my blog there, and started to write the SQL Server Execution Plan Reference. That part of the site went live on May 31, 2018, when I had finished the generic pages plus the…

Video training – new release, big update, and Black Friday sale

October 19, 2026

Hugo Kornelis

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Three months have passed since my previous update on the SQLServerFast Execution Plan Video Training. But I have been working very hard in those three months, and I can now make a few big announcements. The new release You’ve gone a long time without new content. Sure, there were updates with new or updated content in existing videos. But there has not been a new bundle since September 2025. That changes now! I hereby proudly present the release of Block 6, Sorting and Grouping, Advanced Level. A whopping total playing time of almost six hours. All for the low price of…

Storage structures 8 – Vector indexes

October 15, 2026

Hugo Kornelis

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This is part eight in my series on the internals of storage structures. After covering the standard storage types, on-disk rowstore, columnstore indexes, memory-optimized storage, and memory-optimized columnstores, I moved on to more specialized storage structures in parts 5, 6, and 7, where I covered XML indexes, JSON indexes, and spatial indexes. In this part, I will look at an index type that has only been added very recently to the product: vector indexes. Supported versions Support for the vector data type, vector indexes, and vector search, was added as a preview feature in SQL Server 2025 and in Azure…

T-SQL Tuesday 203 – A bad decision

October 13, 2026

Hugo Kornelis

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Welcome back to T-SQL Tuesday, a monthly blog party that was started in 2010 by Adam Machanic. This 203rd edition is hosted by Pat Wright, who invites us to write how to make tough choices when designing database or database code. I have decided to take a rather liberal approach to Pat’s invitation, and write about a decision I made that was … let’s say “not my finest moment”. The problem The client had a nightly load of their data warehouse. The design of their data warehouse was based on the Data Vault principle. In short this means that the…

Keep on going

October 10, 2026

Hugo Kornelis

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(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 over a month since I last gave an update on my leukemia situation. At that time, I was getting ready to start the experimental treatment of a new CAR-T drug. And when I say experimental and new, I mean what I say. Only 18 patients before me have received this drug. The first 12 with another dosage.…

Storage structures 7 – Spatial indexes

October 4, 2026

Hugo Kornelis

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Welcome back to the series on internals of storage structures. I first covered the standard storage types in the episodes on on-disk rowstore, columnstore indexes, memory-optimized storage, and memory-optimized columnstores, and I then started to explore specialized storage structures in the parts on XML indexes and JSON indexes. It is now time to look at spatial indexes. Tessellation To understand spatial indexes, we first need to understand a process known as “tessellation”. This is a process where a shape is divided into smaller elements, that then can be recursively divided even further, to result in a list of cells with,…

New shop!

September 30, 2026

Hugo Kornelis

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Two and a half months ago, I informed you that Vimeo decided to shut down their VOD service, forcing me to find a new platform for hosting my videos and handling the sales. For me, that meant a lot of extra work: finding a new host, then transferring all my content over there, and configuring and setting up the sales platform. But it’s extra work for you as well, if you ever purchased one of my videos. Vimeo refuses to tell me who bought my videos, claiming privacy reasons. So the only way for me to ensure that those who…

Plansplaining part 35. A bug in Table Spool and an invisible property on Stream Aggregate

September 16, 2026

Hugo Kornelis

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Welcome back to the plansplaining series. Probably the one with the longest, and least clickbaity title. The idea of plansplaining is to take a single execution plan and then fully dissect it, until every little thing that is happening is fully exposed and clarified. However, I am only human. I may miss things. And in this case, some things I missed in one of the earliest plansplaining posts are sufficiently interesting to return to that post and talk about the little details that don’t match up, and then make them match up. Frameless window The OVER clause, that can be…

A new treatment starts

September 1, 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.) There has been a long silence in my leukemia diary. Not because nothing happened, but because I kept waiting for the next bit of news. And then the next. I just received news that is totally worthy of an update. So here we go. Second round My last update was between the first and second round of the AZA-VEN…

Game over

Done, but never finished

Video training – new release, big update, and Black Friday sale

Storage structures 8 – Vector indexes

T-SQL Tuesday 203 – A bad decision

Keep on going

Storage structures 7 – Spatial indexes

New shop!

Plansplaining part 35. A bug in Table Spool and an invisible property on Stream Aggregate

A new treatment starts

Game over

Done, but never finished

Video training – new release, big update, and Black Friday sale

Storage structures 8 – Vector indexes

T-SQL Tuesday 203 – A bad decision

Keep on going

Storage structures 7 – Spatial indexes

New shop!

Plansplaining part 35. A bug in Table Spool and an invisible property on Stream Aggregate

A new treatment starts

Hugo Kornelis

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