Power BI Connection to SSAS Tabular Slow

Hi


I'm experiencing unusual behaviour when connecting Power BI Desktop to an on prem Tabular model (2014). Our model has 1000 calculations, any time a user connects to teh Tabular Model, the connection takes 30-40 seconds to complete (time it takes to see the meta data). This happens with every new connection. The server which hosts the tabular model shows the CPU spiking up to 30% per connection therefore 3-5 concurrent connections max out the server.




Running profiler trace on the server, i can see that for each connection, a bunch (number of calculations in the model) MDX execute statements are being fired for each calculation in the model which is the reason behind the delay. even though each MDX statement only only milliseconds to run, the number that can execute at any one time is throttled and the sheer number add up, taking on avg 30 seconds to complete.




This behaviour doesn't occur when i connect to the tabular model using Excel, where the connection is almost instant and there are no MDX execute statements in the background.




In the Power BI service this works slightly differently in that the number of connections is controlled by Power BI/enterprise gateway/Azure Service Bus rather than per user, would it be possible to share more information on how the powerbi.com service manages connections against the on prem server?




thanks

Rahil