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Author: Kevin Feasel

Knowing a Server’s Limits

Published 2020-12-11 by Kevin Feasel

Pam Mooney shows how you can discover and document limits for a SQL Server instance:

Having taken steps to map your database applications to the databases and address your security and backups, you need to turn your attention to your server’s limits.

What do I mean by limits? Certainly, this is an allusion to how you will monitor your server drive capacity, but I also mean how you will track resource limits, such as latency, CPU, memory, and wait stats. Understanding all of these terms, what normal values are for your server, and what to do to help if the values are not normal, will help to keep your servers as healthy as possible.

These measures are big, in-depth topics in and of themselves. This will only serve to get you started. Links to more in-depth resources are included with each topic, and you will doubtless find others as you progress through your career.

Click through for the process.

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Batch Mode with Window Functions and Parallelism

Published 2020-12-11 by Kevin Feasel

Erik Darling has a two-parter on how using batch mode processing when working with window functions can lead to better performance. Part 1 sets the stage:

If you ask people who tune queries why batch mode is often much more efficient with windowing functions, they’ll tell you about the window aggregate operator.

That’s all well and good, but there’s another, often sneaky limitation of fully row mode execution plans with windowing functions.

Let’s go take a look!

Part 2 identifies the culprit:

When queries go parallel, you want them to be fast. Sometimes they are, and it’s great.

Other times they’re slow, and you end up staring helplessly at a repartition streams operator.

Check out both of these posts.

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Data Professional Salary Survey

Published 2020-12-11 by Kevin Feasel

Brent Ozar has another year of the Data Professional Salary Survey:

Take the Data Professional Salary Survey now.

The anonymous survey closes Friday, Jan 1, 2021. The results are completely open source, and shared with the community for your analysis. (You can analyze ’em now mid-flight, but I’d wait until the final results come in. I’ll combine them into a single spreadsheet with the past results.)

I’ve had fun analyzing it over the years. If you wouldn’t mind, please fill it out and add some more data points.

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EDW: Maintenance is Costlier than Development

Published 2020-12-11 by Kevin Feasel

Andy Leonard argues that with an Enterprise Data Warehouse, development is the less expensive side of the coin:

Crossing the threshold between “bad data” and “data that is too bad” is somewhat dependent on how the data is being used by the enterprise.

Don’t let that simplistic-sounding response trip you up. Please recognize two truths about the sentence above:

1. The sentence above has nothing to do with math.
2. The sentence above has everything to do with enterprise culture; specifically, enterprise data culture.

Read the whole thing.

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Setting up Azure Purview for Power BI

Published 2020-12-10 by Kevin Feasel

Soheil Bakhshi has a great step-by-step walkthrough for setting up Azure Purview:

Microsoft newly announced a piece of very exciting news that Azure Purview now supports Power BI. This is massive news from a data governance point of view. Azure Purview is the next generation of Azure Data Catalog with more metadata discovery power and the ability to use sensitivity labels. After reading the news, I immediately decided to set up my test environment and give it a go. I followed the steps mentioned in this article on the Microsoft documentation website but I faced some difficulties to get it to work. And here we are, another blog post to help you to set up the Azure Purview for Power BI.

Click through for a detailed walkthrough.

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All About Dot Plots

Published 2020-12-10 by Kevin Feasel

Cole Nussbaumer Knaflic talks about one of my favorite plot types:

The term “dot plot” can be used for any graph that is encoding data in a dot or small circle. There are a few common types that I’ll focus on here. If you’ve ever asked yourself—What is a dot plot? How do I interpret a dot plot? When should I use a dot plot? or What are pros and cons of dot plots?—you’ll find the answers in this post. I’ll also share some tips on creating them and where to find examples that will inform and inspire.

Read the whole thing.

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A Primer on Locking and Deadlocks

Published 2020-12-10 by Kevin Feasel

John McCormack explains locks and deadlocks:

Blocking is the real world impact of locks being taken on resources and other lock types being requested which are incompatible with the existing lock. You need to have locks in order to have blocking. In the scenario where a row is being updated, the lock type of IX or X means that a simultaneous read operation will be blocked until the data modification lock has been released. Similarly, data being read blocks data from being modified. Again, there are exceptions to these based on the isolation level used.

Blocking then is a perfectly natural occurrence within SQL Server. In fact, it is vital to maintain ACID transactions. On a well optimised system, it can be hard to notice and doesn’t cause problems.

All things in moderation, even blocking.

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Creating Property Names in Powershell

Published 2020-12-10 by Kevin Feasel

Jeffrey Hicks shares some Powershell API design tips:

When you build a PowerShell tool, you want the output to be easy to use. To me, this means having clearly defined property names. Dave has a command in the module to get a Twitter user account. Here’s what it currently writes to the pipeline.

For the sake of demonstration, assume that the Get-TwitterUser command is your code that is invoking a REST API and returning a custom object to the pipeline.

The property names are mostly clear, although not very PowerShell friendly. How many native PowerShell commands do you run that have properties that look like this? Let’s fix this.

Read on to see those properties and how you can make them more Powershell-friendly.

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Troubleshooting an Error: Insufficient System Memory

Published 2020-12-10 by Kevin Feasel

Lee Markup walks us through an issue:

In my own local SQL Server I ran across a problem starting the SQL instance. I went to SQL Server configuration Manager and manually started the SQL Server instance. The UI showed the instance had started. I opened SSMS and tried to connect. And I waited, waited and waited some more until it didn’t connect and threw an error.

Read on to see how Lee was able to find and correct the issue without actually being able to start up SQL Server.

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