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Curated SQL Posts

Capturing Autogrowth Events in SQL Server

Published 2023-09-13 by Kevin Feasel

Ben Miller shares an extended event session with us:

I wanted to share one of the Extended Events I always put on a server when I am in charge of it. It has to do with File growths and captures some important things for me. Before you say that it is in the system_health extended events session, I know that it is there. I have had system_health sessions cycle pretty fast and there are a lot of other events in that trace, so I decided to make my own for just that specific thing so that I can archive the sessions and keep the disk clean as well as pull this information into a table and analyze data in a tabular way instead of mining XE files.

Read on for that script and what it does in practice.

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Restoring Azure SQL DB Indexes

Published 2023-09-13 by Kevin Feasel

Brent Ozar answers a question:

I got an interesting request for consulting, and I’m going to paraphrase it:

We were using Azure SQL DB with automatic index tuning enabled for months. Things were going great, but… we just deployed a new version of our code. Our deployment tool made the database schema match our source control, which… dropped the indexes Azure had created. How do we get them back?

Read on for Brent’s answer.

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A Primer on Latch Waits

Published 2023-09-13 by Kevin Feasel

Kendra LIttle gives us a sneak peek:

I’ve long found it tricky to remember and explain the differences between three similar-sounding waits in SQL Server that all have “LATCH” in the name: PAGELATCH, LATCH, and PAGEIOLATCH waits.

Here’s an illustration that explains these waits, along with wait subtypes.

This is an excerpt from my new comic, “Wait Stats in SQL Server.”

Click through for the excerpt, as well as some more detail on these latch types.

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Plotting SVM Decision Boundaries in R

Published 2023-09-12 by Kevin Feasel

Steven Sanderson goes right up to the edge:

Support Vector Machines (SVM) are a powerful tool in the world of machine learning and classification. They excel in finding the optimal decision boundary between different classes of data. However, understanding and visualizing these decision boundaries can be a bit tricky. In this blog post, we’ll explore how to plot an SVM object using the e1071 library in R, making it easier to grasp the magic happening under the hood.

Read on to see how you can perform this analysis as well.

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Running Apache Kafka in Windows

Published 2023-09-12 by Kevin Feasel

Jim Galasyn gives up the ghost:

Is Windows your favorite development environment? Do you want to run Apache Kafka® on Windows? Thanks to the Windows Subsystem for Linux 2 (WSL 2), now you can, and with fewer tears than in the past. Windows still isn’t the recommended platform for running Kafka with production workloads, but for trying out Kafka, it works just fine. Let’s take a look at how it’s done.

There was a time in which running Kafka on Windows meant downloading Windows-specific installers, workaround executables to deal with NTFS, and all the attendant problems of being the third operating system on the list. Using WSL2 is definitely a better approach.

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Finding Object Counts for S3 Buckets

Published 2023-09-12 by Kevin Feasel

The Big Data in Real World team sees a problem:

There is no separate command in AWS CLI to find the number of objects in an S3 bucket but there is a workaround.

Read on for the solution to this. The way that S3 and Azure Blob Storage (without hierarchical namespaces) store files as tags and treat folders as cosmetic is neat from a technical standpoint, though it goes counter to how we’d expect a file system to behave.

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TINYINT Casts in Spark SQL vs T-SQL

Published 2023-09-12 by Kevin Feasel

Bill Fellows runs into an interesting oddity:

Yet another thing that has bitten me working in SparkSQL in Databricks—this time it’s data types.

In SQL Server, a tinyint ranges from 0 to 255 but both of them allow for 256 total values. If you attempt to cast a value that doesn’t fit in that range, you’re going to raise an error.

SQL Server’s TINYINT data type is an unsigned one-byte number, whereas TINYINT in Spark SQL is a signed one-byte number. But that’s not the biggest difference Bill finds, so check out the post to learn more.

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Controlling Power BI Chart Ranges with DAX

Published 2023-09-12 by Kevin Feasel

Marco Russo and Alberto Ferrrari control the horizontal, Marco Russo and Alberto Ferrari control the vertical:

DAX is a powerful tool in the hands of a Power BI developer. Using simple DAX formulas, you can not only compute interesting metrics but also customize the behavior of Power BI visuals. In this article, we use DAX to control the range of charts to obtain more coherent visualizations.

Read on to see how.

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Documenting Power BI Workspaces with Fabric Notebooks

Published 2023-09-12 by Kevin Feasel

Prathy Kamasami shares a use case for notebooks in Microsoft Fabric:

If you are a consultant like me, you know how hard it can be to access Power BI Admin API or Service Principal. Sometimes, you need to see all the workspaces you have permission for and what’s inside them. Well, I found with MS Fabric, we can use notebooks and achieve it with a few steps:

Read on for an enumeration of those four steps, as well as detailed instructions for each.

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