Dec 18, 2017 10:21 AM|X.Daisy|LINK
I tried your code on my side, commenting the 'stacking:normal' only makes a little effect. Besides, the result charts of two cases are the same on my side. I think you can just comment it.
Then from my point of view, the main reason of taking too much time to load is that it loads too many points. You can refer the following article to improve your code.