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Day: July 9, 2025

Spatial Cross-Validation in R

Published 2025-07-09 by Kevin Feasel

Jakub Nowosad wraps up a series:

This document provides an overview of two R packages, sperrorest and blockCV, that can be used for spatial cross validation, but are outside of standard machine learning frameworks like caret, tidymodels, or mlr3.

All of the examples below use the same dataset, which includes the temperature measurements in Spain, a set of covariates, and the spatial coordinates of the temperature measurements.

Click through for a pair of cross-validation packages, as well as a link to the rest of the series. H/T R-Bloggers.

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Bad Request Error Running Powershell in Azure DevOps

Published 2025-07-09 by Kevin Feasel

Koen Verbeeck wants good requests:

I needed to run a PowerShell cmdlet in an Azure Devops pipeline. The cmdlet in question was New-AzRoleAssignment, but the cmdlet itself isn’t important. What is important is that I needed to pass the object ID of a service principal to the command. Even though I was pretty sure the syntax and everything was correct, I got a “Operation returned an invalid status code ‘BadRequest’” error when the PowerShell was run (inside an Azure PowerShell task):

Read on to see how Koen diagnosed and resolved the issue.

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Random Page Cost and PostgreSQL Query Plans

Published 2025-07-09 by Kevin Feasel

Tomas Vondra takes us through a setting:

Last week I posted about how we often don’t pick the optimal plan. I got asked about difficulties when trying to reproduce my results, so I’ll address that first (I forgot to mention a couple details). I also got questions about how to best spot this issue, and ways to mitigate this. I’ll discuss that too, although I don’t have any great solutions, but I’ll briefly discuss a couple possible planner/executor improvements that might allow handling this better.

Tomas’s points around the random_page_cost setting sound a lot like the cost threshold for parallelism setting in SQL Server in inverse: a setting whose default makes sense in a world of spinning disks at 7200 RPM, but not really in a solid state world.

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The Importance of Power BI Performance Load Testing

Published 2025-07-09 by Kevin Feasel

Gilbert Quevauvilliers runs some tests:

It is becoming increasingly important to understand how the Power BI reports/Semantic Model that are being used in your organization are performing.

When using Fabric Capacities this can potentially be of critical importance, because a single report that is not well designed could cripple or bring down your capacity.

By completing Power BI Performance load testing before it goes into a production environment allows for scalable, dependable, repeatable testing to take place in lower environments.

Read on to see what this entails and the tool Gilbert will use throughout this series.

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