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Month: August 2025

Sideways Recursion in DAX Calculation Groups

Published 2025-08-14 by Kevin Feasel

Marco Russo and Alberto Ferrari’s example goes sideways:

DAX calculation items do not provide full recursion. However, a limited form of recursion is available, known as sideways recursion. We describe this complex topic through examples. Let us start by understanding what recursion is and why it is essential to discuss it. Recursion may occur when a calculation item refers to itself, resulting in an infinite loop within the application of calculation items (read the linked article in case you are not familiar with the concept of “application”, which is different from “execution”). Let us elaborate on this.

Read on for a demonstration of the principle. I haven’t dug into the topic, but I was curious because I’d never heard of “sideways recursion” before. It turns out that there’s some discussion of it in the DAX community and there was something known as Simpson’s sideways recursions from the 1980s, but I’m not sure if that’s the same thing.

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Downloading Power BI Reports from the Power BI Service

Published 2025-08-14 by Kevin Feasel

Gilbert Quevauvilliers wants to download a report:

I am sure we have all had it where there is Power BI report in the service which has been working for a long time. Then there is a requirement to make a change, and NO ONE can find the original PBIX.

There now is an easy way to download the Power BI Report or the Power BI Semantic model from the Power BI Service, and I will show you how to do this!

Click through to see how. No Power BI Report Server jokes this time around, however, because that functionality has been around for a while as long as you have appropriate permissions on the reports themselves.

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Loading Data from Network-Protected Storage Accounts into OneLake

Published 2025-08-14 by Kevin Feasel

Matt Basile grabs some data:

AzCopy is a powerful and performant tool for copying data between Azure Storage and Microsoft OneLake, and is the preferred tool for large-scale data movement due to its ease of use and built-in performance optimizations. AzCopy now supports copying data from firewall-enabled Azure Storage accounts into OneLake using trusted workspace access. Now you can use AzCopy to load data from even network-protected storage accounts, letting you effortlessly load data into OneLake without compromising on security or performance.

Click through for an explanation of trusted workspace access, followed by the steps to try it out for yourself.

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Flags in SQL Server Regular Expression Functionality

Published 2025-08-14 by Kevin Feasel

Louis Davidson continues a series on regular expressions:

In this week’s sixth entry of my learning RegEx series, I am going to do two last intro entries for a while, this one on case sensitivity, and another on multi and single line searches. After this I will move into all of the functions that are available in SQL Server 2025 and Azure SQL (and I will come back if I learn any additional things that we need to cover either right after that, or anytime I learn something new I want to share about RegEx).

Read on to see which flags SQL Server currently supports. Of those, Louis tries out a pair.

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Portfolio Theory and Risk Reduction

Published 2025-08-13 by Kevin Feasel

John Mount continues a series on risk optimization:

I want to discuss how fragile optimization solutions to real world problems can be. And how to solve that.

Small changes in modeling strategy, assumptions, data, estimates, constraints, or objective can lead to unstable and degenerate solutions. To warm up let’s discuss one of the most famous optimization examples: Stigler’s minimal subsistence diet problem.

There are some neat stories in the post as you walk through problems of linear programming.

Also, Nina Zumel has a post on overestimation bias:

Revenue optimization projects can be particularly valuable and exciting. They involve:

  • Estimating demand as a function of offered features, price, and match to market.
  • Picking a set of offerings and prices optimizing the above inferred demand.

The great opportunity of these projects is that one can derive value from improving the inference of the demand estimate function, improving the optimization, and even improving the synergy between these two steps.

However, there is a common situation that can lose client trust and sink revenue optimization projects.

Read on for that article.

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Feature Importance in XGBoost

Published 2025-08-13 by Kevin Feasel

Ivan Palomares Carrascosa takes a look at one of my favorite plots in XGBoost:

One of the most widespread machine learning techniques is XGBoost (Extreme Gradient Boosting). An XGBoost model — or an ensemble that combines multiple models into a single predictive task, to be more precise — builds several decision trees and sequentially combines them, so that the overall prediction is progressively improved by correcting the errors made by previous trees in the pipeline.

Just like standalone decision trees, XGBoost can accommodate both regression and classification tasks. While the combination of many trees into a single composite model may obscure its interpretability at first, there are still mechanisms to help you interpret an XGBoost model. In other words, you can understand why predictions are made and how input features contributed to them.

This article takes a practical dive into XGBoost model interpretability, with a particular focus on feature importance.

Read on to learn more about how feature importance works, as well as the three different views of the data you can get.

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Equalizing Proxy vs Redirect Rates for OneLake Access

Published 2025-08-13 by Kevin Feasel

Elizabeth Oldag announces a pricing change:

We’re thrilled to share a major update and simplification to OneLake’s capacity utilization model that will make it even easier to manage Fabric capacity and scale your data workloads. We are reducing the consumption rate of OneLake transactions via proxy to match the rate for transactions via redirect. This means you no longer have to worry where you are accessing your OneLake data from (via proxy or redirect), they will consume your capacity at the same low rate.

Read on to see what this means in practice.

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Registering Applications to Read Fabric Resources

Published 2025-08-13 by Kevin Feasel

Andy Leonard works in Microsoft Entra:

My older son, Stephen, and I have been vibe coding information-dense solutions for Fabric lately. The latest application is Fabric Navigator, which simplifies navigation between Fabric Data Factory pipelines and notebooks. While Fabric Navigator includes links to instructions about configuring Azure and Fabric security to allow read access to Fabric Data Factory pipelines and notebooks, I feel a walk-through of a minimally-viable security configuration is in order. Hence, this post.

Click through to see what setting you need to make in Entra, as well as settings you need to change in Microsoft Fabric, for this to work.

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Installing SQL Server Instances via dbatools

Published 2025-08-13 by Kevin Feasel

David Seis digs into another dbatools cmdlet:

As DBAs we install SQL Server for various reasons regularly. If you could save time for each installation for more critical tasks, would you?

In this blog post, we will audit the dbatools command Install-Dbainstance. I will test, review, and evaluate the script based on a series of identical steps. Our goal is to provide insights, warnings, and recommendations to help you use this script effectively and safely. Install-Dbainstance is a powerful tool to automate the install and configuration of a new SQL Server instance. It works well in scenarios that require frequent deployments of SQL Server instances.

You can definitely automate installation of SQL Server without the cmdlet, but the dbatools team does a good job of laying out what’s possible that you might not necessarily get just from the config script that the SQL Server installer spits out (and uses when you next-next-next your way to success).

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