Direct Connections Performance and CPU saturations

[arcellie]

Since November we're experiencing very slow performance on Power Bi reporting: reports which required 30-40 secs to update now takes minutes (sometimes they do not update anymore).

This behavior is often causing a big queue of sessions against our On Prem SSAS system, with the result of a CPU saturation of 100% and many users affected.

The issue seemed to be mitigated in the past days, but two days ago we installed the new On Prem Gateway (December Release) and now we're experiencing even worse conditions than before.

Actually we do not have a workaround other than shutdown On Prem gateway to force the timeout of the PBI queries stuck in the system.

[v-lili6-msft]

hi  @arcellie 

I have tested on my side, it works well.

I would suggest you monitor and optimize on-premises data gateway performance as this document:

https://docs.microsoft.com/en-us/data-integration/gateway/service-gateway-performance

and also this document:

https://docs.microsoft.com/en-us/data-integration/gateway/service-gateway-performance-cpu

of course, you could try to restart the gateway and also try to roll back the gateway to Oct version to see if it works well on your side.

https://docs.microsoft.com/en-us/data-integration/gateway/service-gateway-monthly-updates

Regards,

Lin

[arcellie]

Hi @v-lili6-msft ,

interesting reading. Just need more insights on this:

If I don't misunderstand, MashUp Containers are in charge of query parallelism and CPU cores affect heavily parallelism capacity of PBI On Prem Gateway. Could it also affects in some ways SSAS CPU saturation?

Thank you and best regards,

[v-lili6-msft]

hi  @arcellie 

CPU cores affect heavily parallelism capacity of PBI On Prem Gateway, Maybe it  also affects SSAS CPU saturation too.

do you use different version gateway to have a try.

Regards,

Lin

[arcellie]

Another possible situation is the saturation of all SSAS threads and following waiting for the upcoming sessions on PBI reporting (MS explained that every PBI visual launches 2 queries against the SSAS cube via direct connection).

However is there a best practice to understand system capacity related to number of users/direct connection reports?