Performance of a report in PBI service is decreasing when multiple users access it

[tomas93]

I've published a new report into PBI service and everything was running smoothly until multiple users started accessing it at the same time, although the total number of users is still relatively small (about 10 users, which is nothing compared to other reports we have, which are accessed by hundreds of people daily).

Even though the report is very dynamic and uses some heavy DAX measures, I fail to see the reason for this behavior. Last week the performanace issues have become so bad that the report page was constantly loading (for 30+ minutes) without materializing. We had to disconnect the dataset and publish it into the PBI service again, which cleared the cache and solved the issue for the moment, but this is defintely not a long term solution.

At it's peak the dataset size was 900mb in the PBI service even though the .pbix file itself is 17mb. 

The report is imported and according to this thread, number of users shouldn't affect the performance at all:

https://community.powerbi.com/t5/Service/Impact-on-report-Performance-in-Power-BI-service/m-p/139505...

Has anyone experienced something similiar? What could be the reason behind this?

[v-easonf-msft]

Hi,  @tomas93 

The performance of the reports is also affected by RLS. Did you create rls in the report? 

You can refer to this tutorial to troubleshoot slow report performance.

report-performance-troubleshoot#follow-flowchart-steps 

Best Regards,
Community Support Team _ Eason

[Burningsuit]

What you're describing sounds like a live connection issue. That would slow in just the same way, and have a small .pbix file but a large dataset. What sort of data are you connecting to ? Are you creating columns (or tables) in DAX ? that may have the same effect. Normally import mode means all the data is loaded into the datamodel, which is then published to the service. It then won't slow down with multiple accesses and the Dataset sise will not change. What you describe is all true of Direct connections though.

Stuart

[tomas93]

All tables are being loaded into the datamodel using IMPORT mode (storage mode = import) from our database, we don't use Direct Query. There are a few marker columns created in DAX, but nothing out of the ordinary (no DAX tables). There are a lot of complex DAX measures used, though. 

[goncalogeraldes]

Hello there @tomas93 ! I've had a similar problem in one of my PBI reports and I used Dax Studio as an analysis tool for evaluating the reports performance. You can always complement it with other free (or not) tools for performance tuning. Check out this link for further help!

Hope this answer solves your problem! If you need any additional help please tag me in your reply.
If my reply provided you with a solution, pleased mark it as a solution ✔️ or give it a kudoe 👍
Thanks!

Best regards,
Gonçalo Geraldes