Scheduled refresh taking really long and making multiple calls

[jamesoleonard]

We have a data set that uses a web URL to call and get a data set that is returned as a CSV file.  It is a webservice we control so we can see the calls coming in.   When we do an ondemand refresh within PBI online, it takes between 2 to 10 seconds to complete.  When we do a scheduled refresh it shows as taking between 10 to 20 minutes to complete.  What is really concerning to us is that when we look at our logging in the service, we see multiple calls taking place to achieve the scheduled refresh.  Why would a scheduled refresh take so much longer to complete than an ondemand refresh and what would cause it to make multiple calls like this?  

Here is a screenshot from Power BI online showing the scheduled refresh taking 18 minutes.... followed by a screenshot from our logs showing 5 different calls being made for the one scheduled refresh.

[v-ljerr-msft]

Hi @jamesoleonard,

Based on my research, it turns out that the start time for schedule refresh shown on the refresh history is not exact time the refresh started. It's the time that Power BI started to prepare for the refresh, and that's why additional requests are sent(for preparation).

Regards

[jamesoleonard]

Thanks for the comment, but I still don't get why that is necessary to make multiple calls.  It means our systems are taking the overhead of returning the data set 5x in this case.  When we scale this up across a large set of customers that is going to be expensive.  

[v-ljerr-msft]

Hi @jamesoleonard,

In this scenario, I would suggest you create a support ticket on Power BI Support page, and give them your feedback to see if they can provide a solution for you. 

Regards