Understanding Dates in Power BI Quick Measures

As I explained here, Power BI introduced the highly anticipated Quick Measures feature to avoid writing DAX formula for common measures. The feature is still in preview, so make sure you enable it in Power BI Desktop from File, Options and Settings, Options, Preview Features. Many quick measures, such as time intelligence calculations (YTD, QTD, Period Over Period Change, etc.), rely on a date field. The date field could come from a Power BI-provided date hierarchy or a Date table.

Letting Power BI auto-generate date hierarchies is easy but dangerous and limiting. As Chris Webb explains here, Power BI-provided hierarchies could bloat the size of the data model. For example, by disabling them in data in a data model provided by a customer, I was able to reduce the data model size from 300 MB to 30 MB!

Instead, a best practice is to have a Date table. It gives you a control over what date periods you want to include. It also allows you to analyze several fact tables by date in a single visual.

Unfortunately, unlike Power Pivot or Tabular, currently you can’t mark a Date table in Power BI Desktop, even though everything is configured correctly in your model. Attempting to use a date field from a Date table when setting up a quick measure, results in this error.

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A “primary date column” means a field of a Date type in a Date table marked as such. DAX time intelligence functions only work when several conditions are met by the date column, such as must be at date granularity, must be continuous, cannot have duplicate values, etc. Since PowerBI hasn’t verified that a user supplied date column meets all those conditions, it doesn’t allow users to define Quick Measures to prevent unexpected results if user is unaware that they cannot just pick any date column.

So why the teaser then? A primary date column will work if you import a model with marked Date table from Power Pivot or if you connect to Tabular. While waiting for Power BI to let us mark Date tables, the workaround is to use a Power BI-provided hierarchy (at least to get the formula), and then change the formula manually to reference the Date field in your Date table. For an example of how to do this, refer to my blog that I mentioned at the beginning. Just don’t give up on data tables!

Power BI Bookmarks

So far, Power BI has lacked the ability to navigate to particular report element, such as another report page, and to allow you to show/hide visuals. For example, Tableau allows you to add buttons to pages and navigate to another page on button click. Such navigation capabilities are important for story telling and for emphasizing elements on the screen.

This changes with the October release of Power BI Desktop which brings a set of navigation capabilities, including bookmarks, spotlight, and selection page.

Suppose you have a meeting and walk management through the sales performance of your company. You start with a bar chart. There is a decrease in sales in which you can explain by using the Analyze Increase/Decrease which I discussed here. Now you have two visuals on the same page:

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But at the beginning of your presentation, you’d want to bring focus on the bar chart, explain the overall trend, and then focus on why sales have decreased (the waterfall chart). You can use bookmarks to achieve this.

  1. Open the new Selection pane (in the View ribbon tab) and hide the Waterfall chart.
  2. While on the View ribbon tab, check the Bookmarks pane. Click Add to bookmark the state of the current page.
  3. Unhide the waterfall chart and create another bookmark.

Now you have two bookmarks that show/hide visuals on the same page. This is conceptually similar to the Power Point animation pane although bookmarks don’t come up with cool entry and exit animations. Now when you present, you can simply use the Bookmarks pane for navigation the way you can use a Table of Contents (TOC) in a Word document.

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Bookmarks are a welcome new Power BI feature. They are important for data story telling and for improving the navigation experience in a busy report.

Configuring Power Query OData Feeds

Scenario: A customer has implemented a Power BI model that retrieves data by calling the Dynamics CRM OData Feed endpoint. The dataset refresh operation is timing out. They want to increase the timeout setting but unlike connecting to SQL Server, where you can set the timeout duration in the source advanced properties, there is no UI for ODATA.

Solution: If you open the query behind the table, and click the Source step, you’ll see in the Query Editor formula bar the following M code:

= OData.Feed(“https://<tenant>.api.crm.dynamics.com/api/data/v8.1/”)

From the documentation, we realize that OData.Feed can take additional settings and one of them is the Timeout setting that you can pass to the third options argument. For example, you can change the M code to set the timeout to 1 hour:

= OData.Feed(“https://<tenant>.api.crm.dynamics.com/api/data/v8.1/”, null, [Timeout=#duration(0,1,0,0)])

The timeout uses the duration data type which is explained here. Bringing this one step further, you can restrict what records get pulled in the OData.Feed using $filter and also only grab data for the columns you’re using by including the field names in the $select parameters, e.g.

“https://<tenant>.crm.dynamics.com/api/data/v8.1/leads?$filter=<somefield> eq 740110001&$select= <removed list of fields>”

Power BI Premium Reports on Mobile Devices

Can we surface Power BI reports deployed to Power BI Premium Report Server on mobile devices? Yes, and we have three quick options:

  1. Since Power BI reports render in HTML5, they should render in any modern browser.
  2. On iOS and Android devices, consider Power BI Mobile for optimum viewing experience. In Power BI Mobile, go to the Settings and click Connect to Server. Then plug in the report server URL, e.g. http://<servername>/reports. Note that the Power BI Mobile Windows app doesn’t support Power BI Premium Report Server yet. Also, by default your reports will only work if you are on your company intranet or the mobile device connects to your company VPN. To make reports available outside corporate network, you can configure a Web Application Proxy to tunnel in.
  3. For embedding reports on a page, have an HTML page with iframe that request the report by URL passing the embed parameter as explained here.

Power BI can’t reach to your report server? Don’t forget to configure the firewall on the Power BI Premium Report Server to allow inbound connections over port 80, as explained here.

How Do We Start?

How do you start a data warehousing project? Not much different than any complex software project. You break it down to small iterations, e.g. by subject area, design and implement each iteration from beginning to end, and deploy to deliver incremental value. Agile? Perhaps. In my career I’ve seen software methodologies come and go so I’d abstain from applying a label. The main goal is to break complex tasks in smaller increments. You can call it agile if you want. But if I must meet every day for 15 minutes and hold hands (I had to do this a while back because my employer was agile, believe me), or deliver some crappy code in some predefined timeframes (sprints), then agile I am not.

So you stated your first iteration (typically Sales as revenue is an important metric to track). Now what? Next, we identify metrics, aka measures. Should you reverse engineer hundreds of reports that you’ve accumulated over decades to come up with these metrics? I’m too lazy to do this and frankly this very well might be a dead-end road. Instead, I suggest you go to the subject matter expert overseeing this iteration and ask him to a list of metrics (aka measures or facts) that he’d use to analyze his business subject area. He should be able to produce this in minutes. Then you ask him what perspectives he’d like to analyze these metrics and you now have dimensions. Then, you follow the dimensional modeling to come up with the design.

The important thing to remember is your iteration won’t be perfect. Nothing is. There will be gaps and misunderstandings, aka bugs. And that’s fine. That’s life. You keep on refining, extending and building… and you’re never done. Because business evolves and so does BI.

Atlanta MS BI Group Meeting on September 25th

MS BI fans, join me for the next Atlanta MS BI and Power BI Group meeting on September 25th at 6:30 PM. Carlos Rodriquez and Daniel Granadillo from Brightstar will share their experience with Power BI and QlikView. Accelebrate will sponsor the meeting. And your humble correspondent will show you two new cool Power BI features: drillthrough to page and explain increase/decrease.

Presentation: Did Qlik run out of BI Power?
Level: Intermediate
Date: September 25, 2017
Time 6:30 – 8:30 PM ET
Place: South Terraces Building (Auditorium Room)

115 Perimeter Center Place

Atlanta, GA 30346

Overview: Haters are gonna hate. Lovers are gonna love. What about you? Come decide by yourself whether you are a Qlik or a PBI guy/gal. This presentation is intended for anyone who wants to see these two BI tools in action. Carlos and Daniel will show the differences and similarities between QlikView and Power BI. They will perform side-by-side the following:

  • Extract and transform data
  • Create a data model (so to allow cross filtering)
  • Compare features side by side, including hiding/displaying visuals, creating linked objects, role-playing dimensions, what-if scenarios
  • Create a nice dashboard (which tool can actually do it?)
Speaker: Carlos Rodrigues has more than 18 years’ experience as an IT professional and has successfully proven that he is especially adept at translating complex business needs into flawlessly Business Intelligence solutions. In his current role, Director- IT with Brightstar Device Protection, he holds the responsibility of defining the strategic roadmap and overseeing the implementation of the company’s Business Intelligence. He is a recent Georgia Tech MBA graduate (go Jackets 🐝). He enjoys traveling to different places around the world, appreciating the local culture, savoring local culinary styles and mainly, taking thousands of photos using his Nikon gear.

Daniel Granadillo is a Business Intelligence Architect / Developer with more than 10 years of experience around Data Warehouse and Analytics projects. Advocate of the Microsoft BI stack and discovered love at first sight with SSIS. You can find me enjoying the outdoors when not embraced with SQL Server

Sponsor: Accelebrate is an IT training firm headquartered in Atlanta, Georgia, USA that provides on-site and online training on a wide variety of technologies for clients in North America, Europe, and worldwide. Accelebrate is a Prime Sponsor of the Atlanta Microsoft BI and Power BI Group.
Prototype with Pizza “Power BI Page Drillthrough and Explain Increase/Decrease” by Teo Lachev

Power BI Group Security

Power BI security is interwoven with Azure and O365 security. Sure, granting individual users access by entering emails works everywhere but it quickly becomes counterproductive with many users. For example, a large insurance company would like grant report access to 250 users and integrate this report with Dynamics 365. If you secure individually, this will require entering 250 emails three times: Dynamics 365, Power BI, and Row-level Security (RLS). As in the old days, we want to use groups to reduce the maintenance effort because all these users are added to a security group, we can just grant access to the group. And, when users come and leave, we make changes to one place only: the group and everything will work magically. However, nothing is simple and security is no exception. In fact, Office 365 has various group types, as you can see below.

o365groups

To make things even more interesting, all groups are not created equal and currently Power BI supports has a varying degree of supporting them. Things will undoubtedly become more unified in time but for now the following table is meant to help you understand what’s supported and where.

Feature O365 Group O365 Distribution List O365 Security Group Exchange Dynamic Distribution List
App workspace content Yes No No No
App distribution No Yes Yes (with email) No
Dashboard sharing No Yes Yes (with email) No
RLS No Yes Yes No

Let’s start with the features. “App workspace content” means adding group members to a shared app workspace. “App distribution” means publishing an app for a wider distribution, e.g. to the entire organization, as you can do previously with organizational content packs. “Dashboard sharing” means sharing a dashboard by email (the first sharing option in Power BI before workspaces and content packs were introduced). RLS means row-level security, i.e. adding groups as members of an RLS role so that they gain different access to data. Moving to group types, “O365 Group” is the group you’d get when you create a workspace. This type of group is supported by many O365 applications, such as Yammer, SharePoint, Teams, etc. “O365 distribution list” is meant for sending email to multiple users in Outlook Web Access. “O365 Security Group” is Azure Active Directory group (if you sync your on-premises AD to Azure, you’d get O365 security groups too). “Exchange Dynamic Distribution List” allows you to create condition-like groups, e.g. for sending email to everyone.

Are you still with me? One more twist. Due to a bug, app distribution and dashboard sharing requires the O365 security group to have an email assigned. A few more notes:

  • Creation of content: App workspaces in Power BI are meant for authors to collaborate and create content. You need a Power BI Pro license for accessing these workspaces and you cannot yet add AD security groups as members/admins to app workspaces
  • Distribution of content: Once content is created in an app workspace, you can distribute it in two ways:
    • Share out individual dashboards. If the original app workspace is in premium, recipients just need a free license. If not, they need Pro licenses. Also, you can share dashboards to security groups but not O365 groups.
    • Publish out an app from the workspace. If the original app workspace is in Premium capacity, recipients just need a free license. If not, they need Pro licenses. Also, you can publish an app to AAD security groups but not O365 groups.

TIP: If you have Power BI Premium, you can share a dashboard from a Premium workspace to other users. You don’t have to publish an app. This is explained in more details here.

Clear as mud? As I said, I hope that table would become obsolete in a few months when Power BI would support all group types everywhere.

Quick Insights Coming to PBI Desktop

The September release of Power BI Desktop brings Quick Insights in the form of the very nice Explain Increase/Decrease feature (in preview). Suppose you have a column chart and you see a sudden increase or decrease in the chart series. You can now right-click on the bar and then click Analyze, Explain the Decrease menu. This runs the Quick Insights machine learning algorithms to predict what caused the anomaly. As in Power BI Service, Quick Insights produces several reports.

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In this case, one of the Quick Insights visuals informs me that most of the decrease is contributed to the bad performance of one of the sales reps (Stephen Jiang). I could have sliced and diced all day long but I could have found this myself. If I find a particular Quick Insight visual useful, I can add it to the report. From that point, I can use just like any other visual on the report.

The Power BI Desktop Explain Increase/Decrease helps you performing root cause analysis in a blink of an eye.

Currently in the preview, the feature is rough around the edges. For example, I was able to get it to work only if I add a field from a Date table, such as Calendar Year, to the chart. Other limitations include:

You can’t use it if your visual includes:

  • TopN filters
  • Include/exclude filters
  • Measure filters
  • Non-additive measures and aggregates
  • Show value as
  • Filtered measures (it’s the new thing we use for scatter chart in insights)
  • Categorical columns on X-axis unless it defines a sort by column that is scalar. If using a hierarchy, then every column in the active hierarchy has to match this condition
  • Non-numeric measures: Model measure support is limited to sum and count only right now.

There are also limitations in data connectivity:

  • Direct query
  • Live connect
  • On-prem RS
  • Embedding

Power BI Page Drillthrough

The September release of Power BI Desktop adds two very useful features: drilling through another page and explain increase/decrease. SSRS practitioners might find “page drillthrough” similar to SSRS actions. However, instead of navigating to another report, it allows the user to navigate to another page within the same report (at least for now cross-report drillthrough is not supported). Although not as flexible as SSRS actions, PBI page drillthrough expands the Power BI data exploration capabilities. Previously, you had the following drillthrough options:

  1. Dashboard drillthrough – Clicking on a dashboard tile navigates you to the underlying report assuming the tile was produced by pinning a report visual.
  2. See records – This chart-level features allows you to right click a bar and see the data behind it.

I won’t repeat the Microsoft intro (watch it here) but I’ll add a few more notes that the demo doesn’t cover and I find very useful. Consider this report which has two pages: Sales page that shows a sales summary and Customer Orders page that is defined as a drillthrough page. The idea here is to allow the user to drill from the sales summary to the Customers Orders to see the data in more detail.

To “define” the Customer Orders page as a drillthrough target, I had to only add CalendarYear and SalesTerritoryCountry fields to the new Drillthrough Filters area in the Visualizations pane. This is conceptually similar to defining parameters in an SSRS drillthrough report. Interestingly, the summary page automatically detects if the visual has one of the fields used in the Drillthrough Filters area. If it does, it automatically enables the Drillthrough context menu. The context menu is activated even if the summary page has just one of the fields defined as drillthrough filters. For example, if the Sales visual has only Calendar Year, the drillthrough page would show all customer orders for that year. If it has also SalesTerritoryCountry, the drillthrough page would show orders for that year and for that country. If the Sales visual has none of the fields used for drillthrough filters, then Drillthrough won’t show up. In other words, Power BI automatically matches the source fields and drillthrough filters and this saves you a lot of configuration steps, such as to configure parameters, to check which field exist and to pass All to the parameters that don’t exist!

Page BI page drillthrough was one of the most requested features by the community. I’d love to see it extended with the following options in future:

  1. Expression-based filters – This applies not only to drillthrough filters but the other filter types. For example, it will be great to default the filter to value using an expression, e.g. =IF(SELECTEDVALUE()==”, <some value>).
  2. Ability to drill to pages in other reports.
  3. Multiple context-aware drillthrough actions – For example, SSRS allows you define an action for each report element. Currently, PBI page drillthrough takes the entire row context and you can’t define drillthrough targets for specific fields.

Deploying and Processing Azure AS

In the “Processing Tabular from Exotic Clients” blog, I said that if you Azure AS model retrieves data from an Azure database, such as Azure SQL Database, it should also be located in the same Azure data center for faster processing and to avoid data transfer fees between data centers. Let’s elaborate a bit on this and share some performance results from a real-life project.

We deployed two Azure AS instances to North Central and South Central Azure data centers, while the Azure SQL Database was deployed to the South Central data center. Here the stats for processing loading about 35 million rows in Tabular using the Full Process of the AS database. The Azure SQL Database was at P1 performance level and Azure AS was at S1 performance level.

  • South Central: 12 minutes or about 50,000 rows/sec
  • North Central: 19 minutes or about 30,000 rows/sec

As you can see, hosting Azure AS in a different center incurs not only data transfer fees but also increased processing times (more than 50% overhead). Your results will probably vary but just like with on-premises installations, it’s very important to fine tune your queries or SQL views. SSAS is capable of processing more than 100,000 rows/sec on a single thread. However, it can do this if rows from the data source arrive at that speed. If you use custom queries or SQL views, any join or inefficient code can potentially slow down processing times significantly. For example, I typically use SQL views to wrap fact tables to perform ad hoc calculations. Initially, for this project I used the T-SQL AT TIME ZONE clause to perform some time zone calculations in the view. As it turned out, AT TIME ZONE is very slow because it looks in the registry for information about when daylight savings time starts and ends, and needs to work out whether each individual value you’re converting is within that period or not. As a result, processing the model took 6 hours! Once I switched to using SWITCHOFFSET, it went down to 12 minutes.

To quickly test the database throughput, open SSMS (ideally in a VM in the same data region to ignore connection latency) and execute a query that selects a few million rows from a table (make sure to change the Discard Query Results option in the query properties to False to avoid SSMS running out of memory when loading all these rows from the grid and to ignore the time to visualize the data). Then divide the query execution time by the number of rows. This gives you the data retrieval throughput and that will determine how fast SSAS can read the source data.