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Category: Power BI

Using Dataflows to Speed Up Power BI Refreshes

Published 2021-02-23 by Kevin Feasel

Reza Rad shows an interesting use case of Power Query Dataflows:

No matter what caused the data source to be slow (the old technology, performance issues, slow connector, limitations, etc), it will cause the data refresh of the Power BI dataset to become slow. Even if you have an incremental refresh setup, it might not still help much, because sometimes the query folding doesn’t happen. Slow refresh time will not only be bad for the service, but it will be also bad for the developer who has to wait a long time for the data to be available after each refresh.

Read on to see how you can use Dataflows to speed up refresh times (though not speeding up the slow data source itself). Reza also has a video on the topic.

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Refreshing a Single Table in Power BI

Published 2021-02-19 by Kevin Feasel

Marc Lelijveld doesn’t want to wait for everything to reload:

If you want to refresh a Power BI dataset, we all know where to find the refresh button in Power BI Desktop as well as in the Power BI Service. By clicking it, you will trigger the entire dataset to refresh. But sometimes it is more convenient to trigger a single table to refresh. If you want to do this, you can do a simple right-click on a table in Power BI Desktop, but how does this work in the Power BI Service? In this blogpost I will describe how you can trigger a single table refresh in the Power BI Service over XMLA endpoints. Please know, this does require Power BI Premium (either Premium per User or Premium Capacity is fine).

Click through to see how.

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DAX and Case Sensitivity

Published 2021-02-19 by Kevin Feasel

Marco Russo and Alberto Ferrari talk about case sensitivity:

Every new language defines its own rules of case-sensitivity. R and Python are case-sensitive, DAX is not. It is not that one is right and the others are not; it is really a matter of personal taste of the author of the language. We would say that there is an equal number of pros and cons in both choices. Therefore, there is no definitive choice. That said, a choice needs to be made on two aspects: the language itself and the way it considers strings. Pascal, for example, is case-insensitive as a language, but string comparison is case-sensitive. The M language, in Power Query, is case-sensitive despite living in the same environment as DAX. DAX is case-insensitive as a formula language. 

Maybe it’s because I like living in the SQL world so much, but I highly prefer case-insensitivity as the default and case-sensitivity only when necessary.

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Renaming All Column Names on All Tables in One Power Query Statement

Published 2021-02-17 by Kevin Feasel

Soheil Bakhshi has achieved mass production:

I previously wrote a blog post explaining how to rename all columns in a table in one go with Power Query. One of my visitors raised a question in the comments about the possibility to rename all columns from all tables in one go. Interestingly enough, one of my customers had a similar requirement. So I thought it is good to write a Quick Tip explaining how to meet the requirement.

Click through to see how to build an expression which iterates over all columns in all tables.

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Visualizing a Power BI Refresh

Published 2021-02-16 by Kevin Feasel

Phil Seamark has a dashboard which will help understand Power BI dataset refresh times:

Have you ever wondered why a Power BI dataset refresh was taking so long? And more specifically, how much time did the refresh spend on various sub-tasks that aren’t that visible to you via the web-portal?

This article shares a technique you can use to capture events fired during a Power BI refresh and use the results in a Power BI report visualise the results. Have to love the idea of using Power BI to optimise and improve Power BI. 

Click through to get the Power BI report and get step-by-step instructions on how to use it.

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Filtering by Cluster in Power BI

Published 2021-02-16 by Kevin Feasel

Joseph Yeates starts a two-parter:

This is a technique that I have used in reports that analyze a feature in a data set that is at the bottom of a hierarchy. For example, customer that belong to a larger customer segment or accounts that belong to a grouping. The report analyzes information for an individual customer or account; however, we want to bring in some comparisons for other customers or accounts that belong to the same segment, grouping or cluster.

Click through for the technique and stay tuned for part two.

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Power Query Design the Right Way

Published 2021-02-15 by Kevin Feasel

Paul Turley continues a series:

Life is full of choices and trade-off decisions. Let’s say that you need to create a lookup table containing sales regions and this information doesn’t exist in the source database. You could easily create a new table in Power Query using the “Enter Data” feature, and just manually enter the sales regions. This would solve the immediate problem with very little effort, but how will the table be maintained if sales regions are added or change in the future? We could keep the list of values in an Excel file stored in SharePoint for a business owner to maintain when information changes. You could also go all the back back to the beginning of the process and load a dimension table in the source database. IT professionals might take the hardline and say that all data must flow through the data warehouse regardless of the effort and cost. Which of these is the right choice? …it depends on the scope reporting project, and the long-term ownership of the solution. Sometimes quick and convenient are OK but particularly tables that need to scale and handle larger data volumes in the future, the following guidelines are critical.

Read on for Paul’s recommended practices.

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Power BI Model Documentation

Published 2021-02-12 by Kevin Feasel

Marc Lelijveld reflects on an overlooked part of development:

I strongly believe that it is key to describe everything that you have built as part of your Power BI model. As we all have a hate-love relationship with documenting our work, the external tool that I build to document your Power BI solutions could come in useful. In particular everything you add and only exists in your model is important to describe properly. This documentation is key once you share your data model with others and they try to understand the goal of a measure, column or anything else. Other than that, documentation also comes in useful if you handover your solution to your colleague or client.

Read on to see what you can currently document.

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Power BI Tools

Published 2021-02-10 by Kevin Feasel

Benni De Jagere shares a list of useful tools around Power BI:

The External Tools (and the Enhanced Metadata format enabling it) allow end users of Power BI Desktop to call on custom built applications, scripts, .. to augment their developer/designer experience. These days, there’s over 40 (I stopped counting) external tools available, each with their own use case and focal area. When showing off some of the capabilities to my clients, it amazes me to see how quickly they pick up these things, and start building out their own ways of working.

Depending on the client, their IT Compliancy rules, the business and technical requirements, my actual tool belt tends to vary. Not every IT organisation allows user to freely install an application, digitally signed or not, so this is definitely an important one to take into your conversations early on.

Read on for Benni’s choices.

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Testing Power BI Report Server Datasources

Published 2021-02-08 by Kevin Feasel

Aaron Nelson has some cmdlets for us:

I finally did it. I created a function I’ve been wanting to be able to use for *years*. Test-RsRestItemDataSource is here.

I can’t tell you how many times I’ve started to work on a report I was told was working, only to find the connection info was invalid. This wastes valuable time, especially when you’ve already made changes to the report.

Other times, I’ve been asked to figure out why a bunch of subscriptions weren’t working, only to find out it was a simple connection issue. I’ve always wanted a simple PowerShell command to check the credentials of a bunch of reports before I touch anything.

Turns out, it wasn’t that hard to build at all. I only wish I had built it years ago.

Click through to see an example of this, as well as two more cmdlets.

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