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Author: Kevin Feasel

Making a Minimally Intrusive Schema Change

Published 2026-09-14 by Kevin Feasel

Jerry Nixon performs a change:

Schema change is inevitable. We do not get everything right the first time, and even when we do, the world around the database keeps changing. Requirements mature, products evolve, and assumptions that made sense years ago eventually stop matching reality.

Businesses change too. We acquire companies, merge with other customers and systems, enter new markets, and adapt to new opportunities. Sometimes a schema has to change because the original design was wrong. More often, it changes because the business is no longer the same business that existed when the schema was designed.

That is normal. The challenge is not avoiding schema change. The challenge is making those changes without interrupting the applications and users that depend on the database.

Click through for an example of a schema migration. I disagree with Jerry about doing the work in “the application,” mostly because it’s rarely one application controlling a database. If it is, and if there are no automated jobs, ad hoc PowerShell scripts, secondary applications, or other processes in place that could write data to the same database, then fine. But I typically find that to be less common than the alternative.

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The Pain of Time Zones

Published 2026-09-14 by Kevin Feasel

Erik Darling makes an admission:

Erik Darling here with Darling Data, and in this video, we’re going to talk about mostly AT TIME ZONE performance, but also some other interesting stuff about AT TIME ZONE. I’m going to be real honest with you, I hate timezone stuff. I hate all of it. I’ve never taken naturally to it. It’s all too weird, and managing it is just such a nightmare. 

I agree with Erik’s point about storing everything in UTC. Click through to learn how you can slow things down considerably using AT TIME ZONE in certain ways.

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Monitoring Microsoft Fabric Capacity Usage

Published 2026-09-14 by Kevin Feasel

Gilbert Quevauvilliers performs some measurements:

Before using Fabric Capacity operation events, you need to have a Fabric capacity.

In my testing, Capacity Operation Events consumed approximately 230,000 CUs per day.

Based on my usage, an F4 capacity was required to run this continuously each day.

NOTE: This is based on my usage. Your consumption may be slightly higher or lower.

That’s a fair amount of capacity to track how much capacity you’re using.

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Troubleshooting a Fabric Copy Job Connection Closure

Published 2026-09-14 by Kevin Feasel

Reitse Eskens debugs an issue:

This is a very common setup that usually works just fine.

Yet, I ran into something weird that I wanted to share with you. When I set up this copy job, I could reach the database, preview the data, and create the job. No issues. But when I started the actual data transfer, the job ran for two minutes and thirteen to sixteen seconds before throwing an error. On every table.

Click through for the error message, the cause of the error, and how to solve it.

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The Server Room in the Attic

Published 2026-09-11 by Kevin Feasel

Thomas Rushton whips out a story:

Anyway. Big Victorian mill-type building. First floor, document management, printing, post rooms, etc, going up. Second floor – erm… document processing? Finance? Third floor – IT, call center, network room, board room, lawyer-types. Fourth floor, just underneath that slate roof, held a smaller office full of debt recovery specialists, and the main server room.

What could possibly go wrong?

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100 Hours of Work

Published 2026-09-11 by Kevin Feasel

Steve Jones talks about a tough week:

I was a relatively new hire, a former intern, at a large electrical utility in Virginia. I worked as a network admin at a nuclear power plant in Surrey, VA. I showed up at work on New Year’s Eve at 5:00pm. We were planning on deploying a new database server running SQL Server, along with a new application to track radiation exposure for workers. This was a mandated change to our tracking, which needed to go live at midnight. I was supposed to be a bystander, helping developers from our internal group implement the server and then take over administration for the future.

What could possibly go wrong?

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What “Clean Data” Means in Microsoft Fabric

Published 2026-09-11 by Kevin Feasel

Christian Henrik Reich lays it out:

You might have heard countless times that AI needs high-quality and clean data to work properly. However, this is often not accompanied by an explanation of what it actually means. In this post, I will explain how you can achieve this in Microsoft Fabric.

I’ll explain the foundation for how you can prepare your data so your solution can answer business questions, either through reporting or AI.

Clean data alone is not enough. Data also needs to be structured, understandable, and accessible in a way that allows your solutions to answer business questions reliably.

The fancy buzzword that describes a lot of what Christian covers is “ontology” but I appreciate this more detailed description versus relying on a buzzword as a crutch.

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A Pernicious Floppy Disk

Published 2026-09-11 by Kevin Feasel

Deb Melkin deals with disaster:

One morning, the help desk support person came over and said this one client was having performance issues. This was one of the cases where we would just reboot. It was early and there would be plenty of time for everything to be back up and running before the system was needed. So I gave the go ahead to reboot the server.

This did not go well. Read on for the rest of the story.

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DAX at the Correct Granluarity

Published 2026-09-11 by Kevin Feasel

Marco Russo and Alberto Ferrari provide some advice:

DAX code is often short. Understanding the question that the code must answer may be much harder.

Consider a calculation that multiplies a quantity by a rate. The formula appears simple, yet it is correct only if the quantity and the rate are evaluated while the rate has a clear meaning. If you perform the calculation after combining different rates, DAX must aggregate the rates somehow: AVERAGE, MIN, or MAX can return a number. However, returning a number does not make that number meaningful.

Read the whole thing.

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A Trio of Outages

Published 2026-09-11 by Kevin Feasel

Andy Yun has been a part of several outages over the years:

My very first job out of college, I worked at a small boutique internet consulting firm that did some hosting in our back office. We had a T1 line coming into our office, which was a space that was part of a strip mall actually. One summer morning, we’re at our desks doing our thing and “hey, I just lost Internet connection, anyone else?” 

Click through for the conclusion of that story, as well as two other times everything went sideways. This might also be a good time to check your backups and make sure they’re working fine.

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