When should I choose DirectQuery over Import mode for enterprise-level reporting?

All answers to this question.

The decision rests on data volume and the need for "up-to-the-minute" accuracy. Import mode is generally faster because it uses the VertiPaq in-memory engine, but you are limited by the 1GB file size (in Pro) and the need for scheduled refreshes. DirectQuery leaves the data in the source, which is great for massive datasets but puts a heavy load on your SQL server. Yes, some DAX functions are restricted or slower in DirectQuery because they must be translated into T-SQL. If your data only updates hourly, I would actually suggest Import mode with an hourly refresh—it’s much smoother for the end user.

   Answered 2025-09-12 by Carol Foster

Have you looked into "Composite Models"? You can keep your massive historical data in DirectQuery and import the current year’s data for faster analysis.

   Answered 2025-09-13 by Karen Reynolds

• Karen, Composite Models (Dual mode) are a game changer but they can be tricky with many-to-many relationships. Jeffrey, if you go the DirectQuery route, make sure your SQL indexes are perfectly tuned. Every time a user clicks a slicer in Power BI, it sends a fresh query to your database. If those queries aren't optimized on the SQL side, your report will be unusable regardless of how good your DAX is.

     Commented 2025-09-14 by Charles Reed

I'd go with Import mode every time unless the data is over 10GB. The user experience with the "spinning wheels" in DirectQuery often leads to low adoption of the report.

   Answered 2025-09-15 by William Hayes

• Good point, William. Executives hate waiting for visuals to load. Hourly refresh in Import mode is usually "real-time enough" for most high-level business decisions.

     Commented 2025-09-16 by Jeffrey Parker