How does data refresh work in Microsoft Power BI?

Microsoft Power BI - learn about its capabilities

Within the Microsoft Power BI service and tool, users can access data from various sources (e.g. Excel files, CVS, pbix, or data from external services such as Microsoft Dynamics, Google Analytics, Salesforce) in several modes - Import Mode, DirectQuery or LiveConnect. And it is the selected mode that determines the possibility of further refreshing the used data because only in the import mode data needs refreshing.

Refreshing data in Power BI

This is because, in import mode, the Power BI service copies data from an external source into the data set and bases it on the last version currently imported. In other modes, such as DirectQuery or LiveConnect, data is not imported. Instead, direct queries are continuously sent to the external data source the moment the user opens a report or interacts with visualisation, or reports are refreshed automatically every hour or so.

When importing data in Power BI, it is worth bearing in mind the maximum size of data sets depending on the type of data capacity. It is also important to note that to refresh data from some external sources, it may be necessary to set up so-called gateways (data gateways).

Data Refresh Mode and Reporting Automation

Power BI in import mode allows you to refresh data, i.e. re-import it from the sources, both on-demand and according to a user-defined and scheduled schedule.

This greatly helps to automate reporting and data analysis. In addition, different refresh times can be set for each data set. However, there is a limit of 8 refreshes of a data set per day (refreshes via API are also counted), whereas, in the case of Power BI Premium, there is a maximum of 48 refreshes. What is essential, the limit does not include refreshes performed on demand.

Refreshing data in OneDrive

In addition to the traditional data refresh mentioned above, Microsoft Power BI offers the so-called OneDrive service refresh. It occurs when data sets and reports are based on a Power BI Desktop (pbix) file, Excel file or CSV file in OneDrive or SharePoint Online service. Then the Power BI service automatically and cyclically synchronises data sets and reports with the file stored on OneDrive.

Thanks to this, the data are automatically updated every hour or so with any changes that have occurred in the source files. It is also possible to perform such a refresh on user requests. However, it should be borne in mind that in this case, the data set is not refreshed by changes occurring in the original data sources but only by changes occurring in the OneDrive file.