Almost 18 months ago I compared Azure Analysis Services and Power BI Premium for large datasets. At that time, Azure Analysis Services was a clear choice, but it is almost time to update that post with a longer article. Because of time constraints, I just want to quickly review what changed so far, promising a longer and more detailed update in a few months.
These were the features/settings described as important for choosing Azure Analysis Services in my previous post, listed here with what changed since then:
- Memory: Power BI Premium Gen 2 has a different architecture that limits the memory per single database instead of providing a fixed amount of RAM for all the databases in memory. Unless you really need to pin multiple models in memory to guarantee low latency in any condition, Power BI Premium Gen 2 no longer has the limitations we had in Gen1.
- Cost control: you cannot pause/resume Power BI Premium Gen2, unless you use the Embedded license, which might be not feasible for your licensing requirements. If you have up to 100-200 users then the Power BI Premium Per User is a very good value proposition and can be cheaper than the Azure Analysis Services option.
- Scale-out control: Power BI Premium Gen2 still does not have a scale-out option such as Azure Analysis Services has.
- Segment size control: Any large dataset in Power BI Premium now uses the DefaultSegmentRowSize property set to 8M rows, just like Azure Analysis Services. This feature has been implemented a few days ago (in the second half of June 2021), so you might want to reprocess partitions of your dataset to take advantage of the new setting. The default segment row size for Power BI is still 1M rows, so any PBIX published keeps that segment size until you refresh the model.
The technical differences between the two solutions are smaller now, and the different licensing/pricing is becoming the only relevant difference. If Microsoft introduces new licensing options for Power BI Premium to mirror the options in Azure Analysis Services, there will be fewer reasons to choose Azure Analysis Services over Power BI Premium.