As we have found out, when the user runs a PBI report connected to SSAS and gradually clicks on different slicers or tabs of the report, new queries are continuously launched, without cancelling the previously started ones. A user can select slicers asynchronously without waiting for previous actions/queries to be completed, and continously start new and new queries. When new slicers are selected, this should cancel the previously started queries (because parameters have meanwhile changed and they are no more relevant), however they continue running. Even one user can easily "kill" the server by such clicking on slicers and tabs, not even talking about tens or even hundreds of users.
After a while, this leads to an enormous amount of queries running at the same time, consuming a lot of server resources and effectively blocking the server to process new queries. This becomes a huge problem especially when more users are running PBI reports at the same time.
@Karin Not the best possible answer but one way would be to limit the number of slicers on report. Also make sure slicers have require single select on so that only one value is selected at a time. The way power bi works as you've described in your post that it sends queries for each user action is by design so I doubt if that can be changed. Also set a default slicer for your report and so user would only change it if it's really required. You should be able to get more details from internal working of product
Did you read this article from the documentation regarding direct connections to SSAS?
I am spooked about the last bit:
If you pin visuals from a report to the dashboard, the pinned tiles are automatically refreshed every 10 minutes. If the data in your on-premises Analysis Services server is updated, the tiles will get auto-updated after 10 minutes.
I wonder if this means that if you create a dashboard with tiles based on data from you SSAS cube this will make the power bi servers to automatically send a query every 10 minutes per tile - this could also create a lot of queries, so watch out for dashboards.
We are new to O365, Power BI and all it holds, good and bad - it is my hope that this issue has been long ago resolved and not simply tabled into the sunset. We currently have lesss than 10 users , less than a dozen reports each. We have already seen this issue...not a suprise that MS doesn't have a list of "gotchas" - does anyone know of a fix ( besides bouncing the gateway)?