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Month: May 2022

Reversing Strings with Powershell

Published 2022-05-11 by Kevin Feasel

Jeff Hicks solves a challenge:

The warm-up challenge was all about manipulating strings. That alone may not sound like much. But the process of discovering how to do it and wrapping it up in a PowerShell function is where the true value lies.

Beginner Level: Write PowerShell code to take a string like ‘PowerShell’ and display it in reverse.

Intermediate Level: Take a sentence like, “This is how you can improve your PowerShell skills.” and write PowerShell code to display the entire sentence in reverse with each word also reversed. You should be able to encode and decode text. Ideally, your functions should take pipeline input. For bonus points, toggle upper and lower case when reversing the word.

Click through to see both of these solutions in action.

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Window Functions and Tips on Sorting

Published 2022-05-11 by Kevin Feasel

Itzik Ben-Gan shares some good advice:

A supporting index can potentially help avoid the need for explicit sorting in the query plan when optimizing T-SQL queries involving window functions. By a supporting index, I mean one with the window partitioning and ordering elements as the index key, and the rest of the columns that appear in the query as the index included columns. I often refer to such an indexing pattern as a POC index as an acronym for partitioning, ordering, and covering. Naturally, if a partitioning or ordering element doesn’t appear in the window function, you omit that part from the index definition.

But what about queries involving multiple window functions with different ordering needs? Similarly, what if other elements in the query besides window functions also require arranging input data as ordered in the plan, such as a presentation ORDER BY clause? These can result in different parts of the plan needing to process the input data in different orders.

Read on for six tips. By the way, if you see broken images on the page (which I saw at the time of posting), click the broken image icon to see the image. It appears that the problem is just with inline images.

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Getting Cluster File Share Witness Sharepath via Powershell

Published 2022-05-11 by Kevin Feasel

Tom Collins needs some information:

I normally use the Windows reg utility to get the  Cluster File Share Witness sharepath information. This is an example command line on a server returning the File Share Witness details

reg query \\myCluster\HKEY_LOCAL_MACHINE\Cluster\Resources /s /f sharepath

I want to start integrating these sorts of tasks into automated information gathering procedures and migrate this task into the Powershell library. Could you share some Powershell code to get the Cluster File Share Witness sharepath  information

Click through for a Powershell one-liner which gets this information.

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Running Kubernetes Clusters on Windows

Published 2022-05-11 by Kevin Feasel

Boemo Mmopelwa shows off Kubernetes Kind:

Kubernetes production clusters are typically run on cloud platforms. However, running and deploying Kubernetes applications on cloud platforms such as Google Kubernetes Engine is costly. These high costs can restrict the Kubernetes learning process for beginners. However, running Kubernetes clusters locally helps you efficiently test applications without disrupting the production environment or paying for cloud services. 

To make things easier, the Kubernetes team developed two tools,  Minikube and Kind, that allow Kubernetes users to run clusters locally without spending a dollar. This article will cover how to do it with Kind. Kind is a command-line tool used to run Kubernetes clusters locally on your computer using Docker containers. Kind works with Docker by loading Docker containers into Kind clusters. A Kubernetes cluster is a group of nodes used to run containerized applications.

Read the whole thing.

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Chronological Snobbery in the Tech World

Published 2022-05-10 by Kevin Feasel

Andy Leonard wants us off his lawn:

Joking aside, chronological snobbery is a bias rarely discussed in technological circles. As a result, our (me included) tendency is to judge newer technology as better technology. Newer technology often sports cool new features, but it’s not entirely accurate to claim newer is always better. Forty-seven years in this field informs me this is not always the case; there is often some baby in the bathwater of the pervious generation of technology.

It’s more accurate to claim newer technology is often better for some applications.

It’s hard to draw that line between “new technology is better” and “old technology is venerable” appropriately. A lot of this is risk appetite, as we’ve known for decades (Crossing the Chasm is 30 years old, for example): some people will gravitate toward novel technologies faster than others. It’s hard for me to describe the tangled mess of beliefs I have around the topic, so I’ll just say to read Andy’s thoughts and maybe I’ll turn it into an episode of Shop Talk or something…

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Searching for Strings in a Database

Published 2022-05-10 by Kevin Feasel

Aaron Bertrand updates an old tip:

Back in 2015, I wrote a tip called Search all string columns in all SQL Server databases. That tip focused on finding strings within string-based columns in all tables across all user databases. I was recently asked if this could be made more flexible; for example, can it search views as well, and can it search only in a specific database?

Click through for a new version which works in SQL Server 2016 and later.

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Stored Functions in MySQL

Published 2022-05-10 by Kevin Feasel

Robert Sheldon continues a series on MySQL:

In the previous three articles in this series, I focused on creating basic database objects that you can use to get started with MySQL. You learned how to build an initial database and then add tables, views, and stored procedures. In this article, I cover one more important type of object, the stored function, a routine that is stored in a database and can be invoked on-demand, similar to a user-defined scalar function in SQL Server or other database systems.

I’m not familiar enough with stored functions to know if they have the same performance limitations as what we have in SQL Server (specifically around needing to run everything in the function once for each row) but based on a comment at the end of Robert’s post, it does seem that way.

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Partial Update Operations in Cosmos DB

Published 2022-05-10 by Kevin Feasel

Hasan Savran partially deflates the partial update bubble:

Partial Update was one of the most wanted features by Cosmos DB customers. In a regular update operation, you need to send the whole JSON document to Cosmos DB. This can be silly if your data model is large and you want to update one field in it. With a regular update, your request object will be large because you need to send the whole data model. Regular Update operation needs more resources from the client/SDK and network bandwidth.

    You might think that partial updates might cost fewer request units. Unfortunately, this is not the case. Because Cosmos DB still needs to open the JSON document, change the necessary properties and save the data. Cosmos DB uses almost the same amount of CPU and memory for this operation for a regular update or a partial update.

That it costs just about as much as a full write does reduce the value of partial updates. Still, there is some value in reducing bandwidth requirements or making changes where you don’t know the entire contents of the document up-front.

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Counting in KQL

Published 2022-05-10 by Kevin Feasel

Robert Cain continues a series on KQL operations:

The previous post in the series covered the take operator. In that post I mentioned that take was one of the simplest operators in KQL. But it is not the simplest, that honor goes to the count operator.

The count operator does nothing more than takes the piped in dataset and returns the number of rows in it. We’ll see more in a moment.

Click through to see more.

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Thoughts on Technical Interview Questions

Published 2022-05-10 by Kevin Feasel

Steve Jones shares some thoughts:

Redgate had a discussion recently among our developers about our interview process and questions. There has been a standard question asking candidates about 2D arrays, but as one developer pointed out, we don’t use these in our code base. So, why do we ask candidates about this topic?

The developers came up with a different question, actually a series of questions that ask about a class and then how to test parts of this class. We mostly work in C# in a DevOps culture, so this seemed like a good idea. They proposed a scenario with a few questions and then asked current developers to solve the questions and give feedback on the language, structure, and difficulty of the problem.

Read on for Steve’s thoughts. It’s been a minute since I’ve given an interview (a plus side to having a really stable pair of database teams the past couple of years) but one of the things I enjoy doing is taking screenshots of Management Studio in various phases of work and ask “What do you see here? There are no right or wrong answers.” I say the latter because I don’t want you to enumerate through every string you see on the screen; I want you to explain what information of importance you’ve caught.

One big tip for interviewers: instead of algorithmic or gotcha questions, show actual code at the 25th, 50th, 75th, and 95th percentiles of difficulty within your code base, focusing on things a person could understand with about 20-30 lines of code and zero context. “Difficulty” can mean that this code was tough to write, is tough to maintain, or that you have included common (and sometimes uncommon) errors to an otherwise real segment of code. For database developers, that might include things like invalid NULL checks, incorrect assignments, etc. Ask the person to perform a code review and point out what they see that is interesting. That way, you get an opportunity to check their technical bona fides in a realistic but relatively low-pressure scenario by simulating the activities that a person actually would do in the job.

I have more advice but I’ll save that for another day.

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