Why are on demand refreshes so much faster than Scheduled Refreshes

[drad]

This question seems to have been asked before but with no real answers.

It takes 6 seconds for an on demand refresh to happen with one of my reports. This is where I publish directly from the PowerBI desktop app.

It take 13 minutes(!) when the scheduled refresh happens. Why is this 130x slower than on demand!?

[silentthread]

I had the same exact problem. I noticed that if I put it in a different workspace I don't have that problem.  It has something to do with workspace capacity, which is ridiculous.  Try it and let me know if it helps.

[RobertUrbanski]

I experience almost the exact same thing.  On demand refreshes take 4 seconds, scheduled refreshes take 13 minutes (after a 2-3 minute delay to starting).

[v-xicai]

Hi @drad ,

When the model is opened for schedule refresh, its size is checked. If it’s OK, the refresh proceeds, and the model is updated.  If the model now exceeds the maximum size limits, the nextrefresh will fail, as will any attempts to work with the file through a browser, until the size of the model is reduced.

You can learn more: https://docs.microsoft.com/en-us/power-bi/refresh-data

https://whitepages.unlimitedviz.com/2014/02/scheduled-data-refresh-in-power-bi/

Please understand that this link is provided “AS IS” with no warranties or guarantees of content changes, and confers no rights.

Best Regards,

Amy

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[drad]

That may be so, but it doesn't explain why it takes so long. From 6 seconds to 13 minutes is a pretty dramatic difference wouldn't you say?

To be clear, my refreshes aren't failing, they are just taking a significant amount of time to finish.

[v-xicai]

Hi @drad ,

If you still have this issue for Power BI, you'd better create a support ticket in Power BI Support to get further help.

Best Regards,

Amy

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[drad]

I'm more looking for information from the community as this seems to be a widespread issue that hasnt been addressed by microsoft.

[v-xicai]

Hi @drad ,

From the Microsoft Official document https://docs.microsoft.com/en-us/power-bi/refresh-data#setting-a-refresh-schedule , we know:

>>Note also that the configured refresh time might not be the exact time when Power BI starts the next scheduled process. Power BI starts scheduled refreshes on a best effort basis. The target is to initiate the refresh within 15 minutes of the scheduled time slot, but a delay of up to one hour can occur if the service can't allocate the required resources sooner.

Best Regards,

Amy

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[drad]

I appreciate the response Amy, but this has nothing to do with my question.

I know the scheduled refresh will begin not exactly on the scheduled time. I am calculating my refresh time from the start to finish, not the scheduled time to finish. Unless Microsoft is incorrectly timestamping refresh start and end times, which would be a much bigger issue.