Tag: Power Query

DAX, Power BI, Power BI Desktop, Power BI Documenter, Self-Service BI

Thin Reports, Real-world Challenges

Power BI Thin Reports, Real-world Challenges

I previously explained in a blog post what thin reports are and why we should care about them. I also explained Report Level Measures in another blog post. In this post, I try to raise some real-world challenges we face when developing thin reports. I also provide a solution to those challenges.

Report Level Measure Related Challenges

Creating and using Report Level Measures is relatively easy, but there are some challenges that we face from time to time, such as:

  • Distinguishing Report Level Measures from Dataset Level Measures
  • Report Level Measure dependencies

Determining Report Level Measures from Dataset Level Measures

One of the challenges that Power BI Developers face is creating many report level measures. Unfortunately, Power BI Desktop currently uses the same iconography for both types of measures, making it hard to distinguish the actual measures created within the dataset from the report level measures. It gets even more challenging if we need to write technical documentation for an existing thin report. We have to open the PBIX file of the thin report in the Power BI Desktop and click every single measure. If the expression bar appears, the selected measure is a report level measure; otherwise, it is a dataset level measure.

So unless we use third-party tools, which I explain in this post, we must go through the manual process.

Report Level Measure dependencies

Another pain point related to the previous challenge is finding the dependencies between the report level measures. It is crucial to be aware of the interdependencies when doing impact analysis. We need to understand how a change in a report level measure impacts other report level measures. Again, Power BI Desktop does not currently have any options supporting that, so we have to click every measure and read through the DAX expressions to identify the dependencies or use the third-party tools to save development time.

Dataset and Thin Reports Dependency Challenges

The other challenges are even more difficult to overcome relate to interdependencies between datasets and thin reports. Power BI Service provides a lineage view that shows the dependencies between a dataset and its connected thin reports. But the challenges can get more complex to overcome manually. The following are some real-world examples of more complex situations:

  • What if we need to analyse the impact of changes in a dataset measure on all report level measures of the connected thin reports?
  • How do we analyse the impact of changes on a dataset measure on all connected thin reports, including the visuals, filters, etc…?
  • What if we need to tune the performance and we want to find a list of all unused tables or unused fields?

As you can see, the situation can get pretty complex, so manual operations are virtually impossible.

But there is a third party tool we can use which provides heaps of capabilities with a couple of clicks.

Continue reading “Thin Reports, Real-world Challenges” →
Business Intelligence - BI, Data Visualisation, Data Warehousing - DW, Dataflows, DAX, Excel, Power BI, Power BI Desktop, Power BI Service, Power Query

Business Intelligence Components and How They Relate to Power BI

Business Intelligence Components and How They Relate to Power BI

When I decided to write this blog post, I thought it would be a good idea to learn a bit about the history of Business Intelligence. I searched on the internet, and I found this page on Wikipedia. The term Business Intelligence as we know it today was coined by an IBM computer science researcher, Hans Peter Luhn, in 1958, who wrote a paper in the IBM Systems journal titled A Business Intelligence System as a specific process in data science. In the Objectives and principles section of his paper, Luhn defines the business as “a collection of activities carried on for whatever purpose, be it science, technology, commerce, industry, law, government, defense, et cetera.” and an intelligence system as “the communication facility serving the conduct of a business (in the broad sense)”. Then he refers to Webster’s dictionary’s definition of the word Intelligence as “the ability to apprehend the interrelationships of presented facts in such a way as to guide action towards a desired goal”.

It is fascinating to see how a fantastic idea in the past sets a concrete future that can help us have a better life. Isn’t it precisely what we do in our daily BI processes as Luhn described of a Business Intelligence System for the first time? How cool is that?

When we talk about the term BI today, we refer to a specific and scientific set of processes of transforming the raw data into valuable and understandable information for various business sectors (such as sales, inventory, law, etc…). These processes will help businesses to make data-driven decisions based on the existing hidden facts in the data.

Like everything else, the BI processes improved a lot during its life. I will try to make some sensible links between today’s BI Components and Power BI in this post.

Generic Components of Business Intelligence Solutions

Generally speaking, a BI solution contains various components and tools that may vary in different solutions depending on the business requirements, data culture and the organisation’s maturity in analytics. But the processes are very similar to the following:

  • We usually have multiple source systems with different technologies containing the raw data, such as SQL Server, Excel, JSON, Parquet files etc…
  • We integrate the raw data into a central repository to reduce the risk of making any interruptions to the source systems by constantly connecting to them. We usually load the data from the data sources into the central repository.
  • We transform the data to optimise it for reporting and analytical purposes, and we load it into another storage. We aim to keep the historical data in this storage.
  • We pre-aggregate the data into certain levels based on the business requirements and load the data into another storage. We usually do not keep the whole historical data in this storage; instead, we only keep the data required to be analysed or reported.
  • We create reports and dashboards to turn the data into useful information

With the above processes in mind, a BI solution consists of the following components:

  • Data Sources
  • Staging
  • Data Warehouse/Data Mart(s)
  • Extract, Transform and Load (ETL)
  • Semantic Layer
  • Data Visualisation

Data Sources

One of the main goals of running a BI project is to enable organisations to make data-driven decisions. An organisation might have multiple departments using various tools to collect the relevant data every day, such as sales, inventory, marketing, finance, health and safety etc.

The data generated by the business tools are stored somewhere using different technologies. A sales system might store the data in an Oracle database, while the finance system stores the data in a SQL Server database in the cloud. The finance team also generate some data stored in Excel files.

The data generated by different systems are the source for a BI solution.

Staging

We usually have multiple data sources contributing to the data analysis in real-world scenarios. To be able to analyse all the data sources, we require a mechanism to load the data into a central repository. The main reason for that is the business tools required to constantly store data in the underlying storage. Therefore, frequent connections to the source systems can put our production systems at risk of being unresponsive or performing poorly. The central repository where we store the data from various data sources is called Staging. We usually store the data in the staging with no or minor changes compared to the data in the data sources. Therefore, the quality of the data stored in the staging is usually low and requires cleansing in the subsequent phases of the data journey. In many BI solutions, we use Staging as a temporary environment, so we delete the Staging data regularly after it is successfully transferred to the next stage, the data warehouse or data marts.

If we want to indicate the data quality with colours, it is fair to say the data quality in staging is Bronze.

Data Warehouse/Data Mart(s)

As mentioned before, the data in the staging is not in its best shape and format. Multiple data sources disparately generate the data. So, analysing the data and creating reports on top of the data in staging would be challenging, time-consuming and expensive. So we require to find out the links between the data sources, cleanse, reshape and transform the data and make it more optimised for data analysis and reporting activities. We store the current and historical data in a data warehouse. So it is pretty normal to have hundreds of millions or even billions of rows of data over a long period. Depending on the overall architecture, the data warehouse might contain encapsulated business-specific data in a data mart or a collection of data marts. In data warehousing, we use different modelling approaches such as Star Schema. As mentioned earlier, one of the primary purposes of having a data warehouse is to keep the history of the data. This is a massive benefit of having a data warehouse, but this strength comes with a cost. As the volume of the data in the data warehouse grows, it makes it more expensive to analyse the data. The data quality in the data warehouse or data marts is Silver.

Extract, Transfrom and Load (ETL)

In the previous sections, we mentioned that we integrate the data from the data sources in the staging area, then we cleanse, reshape and transform the data and load it into a data warehouse. To do so, we follow a process called Extract, Transform and Load or, in short, ETL. As you can imagine, the ETL processes are usually pretty complex and expensive, but they are an essential part of every BI solution.

Continue reading “Business Intelligence Components and How They Relate to Power BI” →
Excel, Power BI, Power BI Desktop, Power BI Desktop RS, Power Query

Optimising OData Refresh Performance in Power Query for Power BI and Excel

OData has been adopted by many software solutions and has been around for many years. Most solutions are using the OData is to serve their transactional processes. But as we know, Power BI is an analytical solution that can fetch hundreds of thousands (or millions) rows of data in a single table. So, obviously, OData is not optimised for that kind of purpose. One of the biggest challenges many Power BI developers face when working with OData connections is performance issues. The performance depends on numerous factors such as the size of tables in the backend database that the OData connection is serving, peak read data volume over periods of time, throttling mechanism to control over-utilisation of resources etc…

So, generally speaking, we do not expect to get a blazing fast data refresh performance over OData connections, that’s why in many cases using OData connections for analytical tools such as Power BI is discouraged. So, what are the solutions or alternatives if we do not use OData connections in Power BI? Well, the best solution is to migrate the data into an intermediary repository, such as Azure SQL Database or Azure Data Lake Store or even a simple Azure Storage Account, then connect from Power BI to that database. We must decide on the intermediary repository depending on the business requirements, technology preferences, costs, desired data latency, future support requirement and expertise etc…

But, what if we do not have any other options for now, and we have to use OData connection in Power BI without blasting the size and costs of the project by moving the data to an intermediary space? And.. let’s face it, many organisations dislike the idea of using an intermediary space for various reasons. The simplest one is that they simply cannot afford the associated costs of using intermediary storage or they do not have the expertise to support the solution in long term.

In this post, I am not discussing the solutions involving any alternatives; instead, I provide some tips and tricks that can improve the performance of your data refreshes over OData connections in Power BI.

Notes

The tips in this post will not give you blazing-fast data refresh performance over OData, but they will help you to improve the data refresh performance. So if you take all the actions explained in this post and you still do not get an acceptable performance, then you might need to think about the alternatives and move your data into a central repository.

If you are getting data from a D365 data source, you may want to look at some alternatives to OData connection such as Dataverse (SQL Endpoint), D365 Dataverse (Legacy) or Common Data Services (CDS). But keep in mind, even those connectors have some limitations and might not give you an acceptable data refresh performance. For instance, Dataverse (SQL Endpoint) has 80MB table size limitation. There might be some other reasons for not getting a good performance over those connections such as having extra wide tables. Believe me, I’ve seen some tables with more than 800 columns.

Some suggestions in this post apply to other data sources and are not limited to OData connections only.

Suggestion 1: Measure the data source size

It is always good to have an idea of the size of the data source we are dealing with and OData connection is no different. In fact, the backend tables on OData sources can be wast. I wrote a blog post around that before, so I suggest you use the custom function I wrote to understand the size of the data source. If your data source is large, then the query in that post takes a long time to get the results, but you can filter the tables to get the results quicker.

Suggestion 2: Avoid getting throttled

As mentioned earlier, many solutions have some throttling mechanisms to control the over-utilisation of resources. Sending many API requests may trigger throttling which limits our access to the data for a short period of time. During that period, our calls are redirected to a different URL.

Tip 1: Disabling Parallel Loading of Tables

One of the many reasons that Power BI requests many API calls is loading the data into multiple tables in Parallel. We can disable this setting from Power BI Desktop by following these steps:

  1. Click the File menu
  2. Click Options and settings
  3. Click Options
  4. Click the Data Load tab from the CURREN FILE section
  5. Untick the Enable parallel loading of tables option
Disabling Parallel Loading of Tables in Power BI
Disabling Parallel Loading of Tables in Power BI Desktop
Continue reading “Optimising OData Refresh Performance in Power Query for Power BI and Excel” →
Dataflows, Power BI, Power BI Desktop, Power BI Embedded Capacity, Power BI Premium Capacity, Power BI Service, Power BI Web App, Power Query

Incremental Refresh in Power BI, Part 1: Implementation in Power BI Desktop

Incremental-Refresh-in-Power-BI-Part-1-Implementation-in-Power-BI-Desktop

Incremental refresh, or IR, refers to loading the data incrementally, which has been around in the world of ETL for data warehousing for a long time. Let us discuss incremental refresh (or incremental data loading) in a simple language to better understand how it works.

From a data movement standpoint, there are always two options when we transfer data from location A to location B:

  1. Truncation and load: We transfer the data as a whole from location A to location B. If location B has some data already, we entirely truncate the location B and reload the whole data from location A to B
  2. Incremental load: We transfer the data as a whole from location A to location B just once for the first time. The next time, we only load the data changes from A to B. In this approach, we never truncate B. Instead, we only transfer the data that exists in A but not in B

When we refresh the data in Power BI, we use the first approach, truncation and load, if we have not configured an incremental refresh. In Power BI, the first approach only applies to tables with Import or Dual storage modes. Previously, the Incremental load was available only in the tables with either Import or Dual storage modes. But the new announcement from Microsoft about Hybrid Tables greatly affects how Incremental load works. With the Hybrid Tables, the Incremental load is available on a portion of the table when a specific partition is in Direct Query mode, while the rest of the partitions are in Import storage mode.

Incremental refresh used to be available only on Premium capacities, but from Feb 2020 onwards, it is also available in Power BI Pro with some limitations. However, the Hybrid Tables are currently available on Power BI Premium Capacity and Premium Per User (PPU), not Pro. Let’s hope that Microsft will change its licensing plan for the Hybrid Tables in the future and make it available in Pro.

I will write about Hybrid Tables in a future blog post.

When we successfully configure the incremental refresh policies in Power BI, we always have two ranges of data; the historical range and the incremental range. The historical range includes all data processed in the past, and the incremental range is the current range of data to process. Incremental refresh in Power BI always looks for data changes in the incremental range, not the historical range. Therefore, the incremental refresh will not notice any changes in the historical data. When we talk about the data changes, we are referring to new rows inserted, updated or deleted, however, the incremental refresh detects updated rows as deleting the rows and inserting new rows of data.

Benefits of Incremental Refresh

Configuring incremental refresh is beneficial for large tables with hundreds of millions of rows. The following are some benefits of configuring incremental refresh in Power BI:

  • The data refreshes much faster than when we truncate and load the data as the incremental refresh only refreshes the incremental range
  • The data refresh process is less resource-intensive than refreshing the entire data all the time
  • The data refresh is less expensive and more maintainable than the non-incremental refreshes over large tables
  • The incremental refresh is inevitable when dealing with massive datasets with billions of rows that do not fit into our data model in Power BI Desktop. Remember, Power BI uses in-memory data processing engine; therefore, it is improbable that our local machine can handle importing billions of rows of data into the memory

Now that we understand the basic concepts of the incremental refresh, let us see how it works in Power BI.

Implementing Incremental Refresh Policies with Power BI Desktop

We currently can configure incremental refresh in the Power BI Desktop and in Dataflows contained in a Premium Workspace. This blog post looks at the incremental refresh implementation within the Power BI Desktop.

After successfully implementing the incremental refresh policies with the desktop, we publish the model to Power BI Service. The first data refresh takes longer as we transfer all data from the data source(s) to Power BI Service for the first time. After the first load, all future data refreshes will be incremental.

How to Implement Incremental Refresh

Implementing incremental refresh in Power BI is simple. There are two generic parts of the implementation:

  1. Preparing some prerequisites in Power Query and defining incremental policies in the data model
  2. Publishing the model to Power BI Service and refreshing the dataset

Let’s briefly get to some more details to quickly understand how the implementation works.

  • Preparing Prerequisites in Power Query
    • We require to define two parameters with DateTime data type in Power Query Editor. The names for the two parameters are RangeStart and RangeEnd, which are reserved for defining incremental refresh policies. As you know, Power Query is case-sensitive, so the names of the parameters must be RangeStart and RangeEnd.
    • The next step is to filter the table by a DateTime column using the RangeStart and RangeEnd parameters when the value of the DateTime column is between RangeStart and RangeEnd.

Notes

  • The data type of the parameters must be DateTime
  • The datat tpe of the column we use for incremental refresh must be Int64 (integer) Date or DateTime.Therefore, for scenarios that our table has a smart date key instead of Date or DateTime, we have to convert the RangeStart and RangeEnd parameters to Int64
  • When we filter a table using the RangeStart and RangeEnd parameters, Power BI uses the filter on the DateTime column for creating partitions on the table. So it is important to pay attention to the DateTime ranges when filtering the values so that only one filter condition must have an “equal to” on RangeStart or RangeEnd, not both
Continue reading “Incremental Refresh in Power BI, Part 1: Implementation in Power BI Desktop” →