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Curated SQL Posts

Building a Type-6 Slowly Changing Dimension

Published 2026-06-11 by Kevin Feasel

Dinesh Asanka creates a dimenson:

In a data warehouse, one important concept is to retain historical data. This data is typically not available in operational systems. One approach in data warehouses is the use of Slowly Changing Dimensions (SCDs). What are the SCD options and are there any new approaches?

Click through for a quick depiction of Types 0 through 3, and then where 6 fits into the mix. I’m not 100% sure I’ve ever actually used a Type-6 slowly changing dimension in a production environment, though there are specific circumstances in which one could be quite useful.

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Query Execution vs Query Processing

Published 2026-06-11 by Kevin Feasel

Louis Davidson disambiguates a pair of terms:

There have been a lot of posts on LinkedIn of late about the “logical execution order” of a query that all really miss some really big points. I was corrected myself in some terminology because I mistook the term “processing” to mean the same as “order” in these discussions when I was explaining why logical execution order is not what people expected.

Click through for a good explanation, as well as a plan to have your company pay for your Disney World trip.

I also appreciate how Louis still calls it SQL Sentry Plan Explorer because that’s what it always will be in my heart.

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On-Prem Is Still On-Prem

Published 2026-06-11 by Kevin Feasel

Andy Brownsword reminds us that it’s still the same animal:

Cloud solutions have sliders which magically reduce downtime, performance issues, and account credit. When you build it, infrastructure and platforms are your challenge, and you get one shot to right-size it. Capacity, resilience, capabilities. They’re your challenges to solve. There is no cake slider.

It’s the capabilities I want to consider here. The capabilities we have available to us day-to-day. Potentially two opposing sides:

To summarize things, everything is awful, just as it always has been. Granted, that may not be how Andy would summarize things, but that’s why I get those big Curated SQL bucks.

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Re-Migration and Data Engineering

Published 2026-06-11 by Kevin Feasel

Andy Leonard shares some thoughts:

Right-sizing didn’t always work out the way some clients were led to believe it would.

In nearly every instance, the right-sizing argument was presented (sold) as the solution to over-provisioning, or purchasing hardware to serve peak loads. The classic example was a US income tax service that needed more and faster compute available to meet increasing demand starting in late January and peaking in mid-April each calendar year. After mid-April, hardware that was beefy enough to handle that peak load sat mostly idle for the next 9 months.

I don’t think I’ve ever worked for a company where this scenario really made sense. Even in the e-commerce company where a sizable fraction of our total annual revenues happened over a 5-day period, the load was still significant enough the rest of the year that we made good use of our on-premises SQL Server hardware.

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Identity Columns in Fabric Runtime 2.0

Published 2026-06-11 by Kevin Feasel

Jon Lunn is happy:

Fabric Runtime 2.0 is in public preview, and there is one small change for this that makes my life as a data engineer a little bit easier. Identity columns. I miss the good old T-SQL Identity column “Id INT IDENTITY(1,1)”, now we have something like it in Spark/Delta.

So with the the old spark/delta table runtime, you couldn’t have an default, automatically increasing column. But now we have these updates.

Click through to see how it works.

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The Vendor-Security Researcher Relationship

Published 2026-06-10 by Kevin Feasel

Andreas Wolter shares some thoughts:

The recent public discussion around YellowKey and Microsoft’s vulnerability disclosure process has put vulnerability research, coordinated disclosure, and Microsoft’s Security Response Center (MSRC) into the spotlight.   While that specific discussion is about Windows and BitLocker, it exposes a broader problem that many researchers recognize: vulnerability disclosure is often framed as a simple responsibility of the researcher.

The idealized workflow is straightforward: find the issue, report it, wait for the vendor, and accept the outcome.

But coordinated disclosure cannot be a one-way obligation.

Andreas shares some perspective from having been a top security person on the SQL Server team. Along the way, he hits one on of my bugbears: the fact that there is no easy way to tell exactly what login X (or user X) can do on a SQL Server instance. The closest I ever got was to impersonate user X and run sys.fn_my_permissions() in the context of that user. But even that isn’t perfect.

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The Muddy World of Hybrid Environments

Published 2026-06-10 by Kevin Feasel

Deborah Melkin muddies up the waters a bit:

My first reaction to this sentence was: Oh look, he assumes that everyone is in the cloud…

My next reaction was: Oh look, he acknowledged that maybe everyone isn’t in the clouds in his follow-up examples.

Since the cloud was introduced, the assumption was always going to be everyone will moving to the cloud. “You’ll be behind if you don’t learn the cloud,” they said. Then as people either moved or started looking into moving their databases, they realized they just couldn’t – whether it was due to missing features, higher than expected costs, etc. There was always some reason.

Click through for some of the challenges and realities of organizations where certain cloud-first or cloud-only services would be a major challenge, versus other services that are typically easier to deal with.

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Gotchas for a Move On-Premises

Published 2026-06-10 by Kevin Feasel

Brent Ozar lists three pain points:

For T-SQL Tuesday #199, Koen Verbeeck posed an excellent question: if your company moved up to the cloud, but after migrating, had to come back on-premises, what would be the big problems?

I’ve had clients in this exact situation! Here are some of my favorite gotchas from those experiences.

Click through for those three. I’d say that the first one is a major issue and will probably be one for the next couple of years—unless the bottom drops out sooner than I expect and we suddenly have a rush of used hardware from highly unprofitable organizations hit the market.

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Thoughts on a Cloudless World

Published 2026-06-10 by Kevin Feasel

Mike Donnelly has some tongue-in-cheek responses:

There are some serious angles to this topic, and I have had conversations with people at conferences who are doing a remigration from the cloud, but it feels like the exception not the rule. It is interesting to think about. I spent most of my career working with on-prem SQL Server, but there was a period of about 10 years (the consulting years) where I didn’t touch anything that wasn’t in the cloud. The past several years have been working in a hybrid environment, but most of the work has been moving things to Azure and Fabric. Koen has some prompts for what our blog posts could be about, but rather than dive deep into any one thing I’m going to go with the blog writer’s best friend – a top 10 list.

The funny thing is, in my time as an on-premises DBA, I never dealt with hardware and didn’t have access to the server room.

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The Importance of Working with People

Published 2026-06-10 by Kevin Feasel

Mark Wilkinson hits migration from a different angle:

I haven’t written a blog post (here) in over 5 years, so what better time to start things back up than a T-SQL Tuesday? Big shout out to Koen Verbeeck for hosting this month, and picking a great topic: Back to on-prem?

As someone that just ended a 10+ year stint managing a hybrid environment, this topic is very near and dear to me. I went back and fourth on what to write about for this one. There are a lot of great topics. Reliability and observability almost won out but instead I landed on maybe an unexpected topic: soft skills.

Regardless of whether your company is fully on-prem, fully in the cloud, fully hybrid, or fully without a clue, Mark’s advice hits home. And is also one of those things I’ve struggled with.

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