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Curated SQL Posts

Don’t Use FLOAT for Currency Data

Published 2026-04-13 by Kevin Feasel

Vlad Drumea has a public service announcement:

In this post I provide some examples as to why FLOAT isn’t the best option for storing exact financial data in SQL Server.

During the last couple of years I’ve seen quite a few cases of FLOAT being used to store financial data in SQL Server.
This isn’t ideal due to how the FLOAT data type behaves in SQL Server, and the official documentation makes a clear note of that.

I’m crotchety enough about this to say that you shouldn’t use any sort of decimal data type (DECIMAL, MONEY, etc.) when dealing with currency data in important financial contexts, either. I reach for BIGINT and divide by 100 (or 10,000 if you keep to four spots after the decimal) for the presentation layer.

For cases in which my data isn’t the source system of record for financial transactions, DECIMAL is fine. I don’t generally like MONEY as a data type in any circumstance, to be honest.

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Unit Testing DAX via Semantic Link

Published 2026-04-13 by Kevin Feasel

Jens Vestergaard writes a test:

Every BI developer has felt it. You change a measure, update a relationship, or rename a column in a semantic model, and then you spend the next hour clicking through report pages to check if something broke. Manual spot-checking is how most teams validate DAX today. It works until it does not.

I have been building and maintaining semantic models for years. The further I get into Fabric-based development, the more my models start to feel like production code. They power dashboards that drive decisions. They feed downstream pipelines. When something breaks, the blast radius is real. And yet, the testing story has always been: deploy, open the report, squint at the numbers.

That gap bothered me enough to do something about it.

Click through to see what Jens has done.

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Write Storms and PostgreSQL

Published 2026-04-13 by Kevin Feasel

Shaun Thomas talks checkpoints:

Every database has to reconcile two uncomfortable truths: memory is fast but volatile, and disk is slow but durable. Postgres handles this tension through its Write-Ahead Log (WAL), which records every change before it happens. But the WAL can’t grow forever. At some point, Postgres needs to flush all those accumulated dirty pages to disk and declare a clean starting point. That process is called a checkpoint, and when it goes wrong, it can bring throughput to its knees.

One thing I would note is that direct-attached nVME storage is approximately 1 order of magnitude slower than RAM. Yeah, that’s still a lot slower, but the gap has closed significantly. If you have PCIe 5 nVME drives (call that 12-14 GB/sec) and relatively slow RAM (20 GB/sec), it’s getting close to on par. But once you move past the top-of-the-line for disk speed, you add more orders of magnitude and everything Shaun describes becomes a problem again.

Jeremy Schneider offers a follow-up involving autovacuum_cost_delay:

A few days ago, Shaun Thomas published an article over on the pgEdge blog called [Checkpoints, Write Storms, and You]. Sadly a lot of corporate blogs don’t have comment functionality anymore. I left a few comments [on LinkedIn], but overall let me say this article is a great read, and I’m always happy to see someone dive into an important and overlooked topic, present a good technical description, and include real test results to illustrate the details.

I don’t have any reproducible real test results today. But I have a good story and a little real data.

Check out both of those articles.

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Defaulting Power BI Slicers to the Current Month

Published 2026-04-13 by Kevin Feasel

Meagan Longoria fixes an annoyance:

There is currently no way to set a default value in a Power BI slicer visual. If you create a report with a slicer for month and choose the current month (e.g. April 2026), save the report, and then come back to the report a month later, your original selection will be enforced and the data will now show the prior month. So how do you make reports with slicers show data for the current month by default while allowing users to select other months as needed? This video shows 3 options.

Click through for the video, as well as seeing which of the three is Meagan’s preferred route.

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Third-Party Semantic Model (Lack of) Support in Power BI

Published 2026-04-13 by Kevin Feasel

Chris Webb lays out an explanation:

I’ve been working with Microsoft BI tools for 28 years now and for all that time Microsoft has been consistent in its belief that semantic models are a good thing. Fashions have changed and at different times the wider BI industry has agreed and disagreed with this belief; right now, semantic models are cool again because everyone has realised how important they are for AI. As a result, some of Microsoft’s partners and competitors (and sometimes it’s not clear which is which) have invested in building their own semantic models and/or metrics stores, some of which don’t work at all with Power BI and some of which only work with significant limitations. This naturally raises the question of whether Power BI will ever work properly with them. The answer is no, and in this blog post I’ll explain why.

Read on for Chris’s explanation.

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SQL Server Kubernetes Operator

Published 2026-04-13 by Kevin Feasel

Anthony Nocentino shares a new project:

Are you considering replatforming your SQL Server workload due to recent vendor changes, but still need high availability and disaster recovery? You’re not alone. One of the challenges with running SQL Server on Kubernetes is that there’s no Kubernetes operator available. That means no automated lifecycle management, no automatic failover, and no standard way to bootstrap an Always On Availability Group on Kubernetes.

I’m excited to share it today as an open-source project: sql-on-k8s-operator. Let’s go.

Click through to see what it entails. All in all, that’s really cool.

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Reviewing Blocking and Deadlocking

Published 2026-04-10 by Kevin Feasel

Erik Darling digs into more functionality in his performance monitoring tool:

In this video, I delve into the blocking and deadlock monitoring capabilities of FreeSQL Server Performance Monitoring, a tool I’ve developed and made available on GitHub. With a focus on practicality and ease-of-use, I explain how we leverage extended events for both blocking and deadlock scenarios, ensuring that you can identify and address performance issues efficiently. Whether you’re using system health or prefer to rely on the block process report, my monitoring tool streamlines the process by automatically setting up necessary configurations and providing easy-to-understand visualizations of your SQL Server’s performance trends over time.

Click through for the video and transcript.

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Defining a Data Contract

Published 2026-04-10 by Kevin Feasel

Buck Woody becomes accountable:

A businessperson pulls a report from a data warehouse, runs the same query they’ve used for two years, and gets a number that doesn’t match what the finance team presented at yesterday’s board meeting. Nobody changed the report. Nobody changed the dashboard. But somewhere upstream, an engineering team renamed a field, shifted a column type, or quietly altered the logic in a pipeline, and nobody thought to mention it because there was no mechanism to mention it.

While we think of this as an engineering failure, it’s more of an implied contract failure. More precisely, it’s the absence of a formal contract. Data contracts are one of the most practical tools a data organization can adopt, and one of the most underused. The idea is not complicated: a data contract is a formal, enforceable agreement between the team that produces data and the team that consumes it. It defines what the data looks like, what quality standards it must meet, who owns it, and what happens when something changes. Think of it as the API layer for your data, the same guarantee a software engineer expects from a well-documented endpoint, applied to the datasets and pipelines your business depends on. This post is about why that matters at the CDO level and how to get them put in place.

Click through to learn more about what data contracts are and why they are useful. This post stays at the architectural level rather than the practitioner level, but lays out why it’s important to think about these sorts of things.

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Mirroring SQL Server 2025 to Microsoft Fabric

Published 2026-04-10 by Kevin Feasel

Reitse Eskens digs in:

Maybe you’ve read my blog post in the DP-700 certification series about mirroring data. You can find that one here. This blog will be longer and more technical. And involve SQL Server. To make reading a little easier, I’ve listed the Microsoft Learn pages at the end of this blog post.

While writing the DP-700 post, I realised I wanted to dig a little deeper. Not only because I’m presenting a session on this subject, but also to learn more about the processes behind it. And, there’s SQL Server involved, something I still have a soft spot for in my heart. Or maybe even more than that.

The fact that your SQL Server instance has to be Arc-enabled is a bit annoying.

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Updates to Fabric Eventstream

Published 2026-04-10 by Kevin Feasel

Alicia Li and Arindam Chatterjee share some updates:

Over the first quarter of 2026, Fabric Eventstreams shipped meaningful improvements across three themes that have repeatedly come up in feedback from our broad community of customers and partners: broader connectivity, richer real-time processing, and secure enterprise‑ready networking and operations.

This post highlights some of the most impactful new Eventstreams-related features and capabilities delivered between January and March 2026.

Click through to see what’s new. Some of this is GA, though a good amount is in preview.

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