Create User-Defined Aggregations for Report Building using a centralized Semantic Model

Hi dgefcoe ,

Thanks for reaching out to the Microsoft fabric community forum.

Currently, Power BI does not allow user-defined (per-report) aggregations in composite models that use DirectQuery to connect to a shared Semantic Model. Aggregation awareness works only within the same semantic model, so local Import tables in a report are not seen as valid aggregations for the main dataset. This means queries still go to the DirectQuery source, leading to slower performance.

To achieve your goal, you can define aggregations directly in the central Semantic Model for shared use, or create specific semantic models for each reporting need with the necessary aggregation tables. Alternatively, you could pre-aggregate data in Fabric Warehouse or Dataflow Gen2 before importing it into your report model.

we suggest sharing this scenario and feedback through the Fabric Ideas - Microsoft Fabric Community so it can be reviewed for future consideration by Microsoft’s product team.

Hope this helps. Please feel free to rech out for any further questions.

Thank you .