Composite Models (Preview)
It was a common request for Power BI to allow you to connect to more than one data source using DirectQuery. It wasn't possible to connect to any other data source in the same report and to include data that has been imported. In the new update, the new Composite Models feature removes this restriction; meaning on a single report, you can seamlessly combine data from one or more DirectQuery sources, and you can also combine data from a mix of DirectQuery sources and import data.
Composite Models include a brand new feature call 'Dual Storage Mode'. This feature allows a copy of the data from a table will be imported, and any visuals that reference only columns from this will us the imported data and not placing a query to the underlying source. This improves performance and lessened load on the backend source.
Follow this path to enable these new features in Power BI Desktop:
Options and Settings
and then select
Once you've enabled this, you can start importing additional tables to your DirectQuery model with no additional changes to your report. To take advantage of the Dual Storage model, you can set this for a table in the field properties pane.
You will then be able to see the storage mode in the tooltip for the table as well.
The status bar on the bottom right of your report will show a storage mode of 'Mixed' when you have DirectQuery and import tables. Clicking this allows all table to be switched to import mode easily.
While this feature is in preview, it is currently not possible to publish a model that uses any of these features to the Power BI Service.