Slow sheduled refresh, fast on-demand refresh

[wicker]

I have a small report. It consists of 3 tables (google BQ table ~200k rows, and 2 mysql tables ~50 rows). There's no large calculations inside - some arifmetic + measure. I published it on app.powerbi.com and there is a problem:

On-demand refresh takes ~20secs, but sheduled refresh ~13min. See screenshot, please. What's a problem?

[v-xicai · Accepted solution]

Hi @wicker ,

From the Microsoft Official document https://docs.microsoft.com/en-us/power-bi/refresh-data#setting-a-refresh-schedule , we know when the model is opened for schedule refresh, its size is checked. If it’s OK, the refresh proceeds, and the model is updated. 

>>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.

Please set schedule refresh for different datasets at different times, make sure that you don't schedule more than max parallel refreshes for the different nodes in these capacities. Also we suggest that you first disable all refreshes on all capacities. Then slowly enable the refreshes one by one. Make sure refreshes are staggered apart (e.g. 1 hour apart), and that no more than max concurrent refreshes happen at overlapping time periods.

You may try to improve the performance for the data model, see Power BI performance best practices , Power BI Performance Tips and Techniques.

For reference:

https://docs.microsoft.com/en-us/power-bi/refresh-data

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

Best Regards,

Amy 

Community Support Team _ Amy

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

[nickyvv]

Hi @wicker,

Is it shared or Premium capacity?
it could be that the scheduled refresh is throttling because there are lots of other things and refreshes happening at the same time. I'm not sure how that reflects in the Start and End times, but if the refresh already started and users query the capacity heavily, I can imagine that the refresh is scaled down on resources, so that the users still have a good performance.

[wicker]

It's PRO license, not Premium. It's surprising - 50 times difference between on-demand and sheduled refresh.