A solution could be something like;
1 – build a helper object
2 – build a seperate microflow where you retrieve the data over a REST call and associate it to your helper object (assuming it is not that much data, if so just hang what you need in further processing)
3 – give the helper object as a data view around your chart
4 – change your datasource of the chart into a microflow datasource, wherein you can give the helper object as a parameter and you can retrieve the chart data and return it as a list to your chart
5 – create an on change microflow with a helper object as your parameter, where you can retrieve the non persistent data over the helper object
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