I am noticing performance issues when using a hosted view layer, eventually causing the featureinfo widget to fail. I did some testing and it looks like performance starts to go down when the hosted view has over 50k records. Somewhere past 82k, the widget will fail.
Here is an example. I have a hosted feature layer of parcels at about 113k records. I created a joined view from this layer. Both layers are used in the EB application in a featureinfo widget. Using the select tool I can select a parcel from the hosted feature parcel layer and the widget displays its details instantly. I then try to change the widget to the hosted, view layer to see the additional details and it is unable to show them. It seems to time out and just shows the default message.
If I allow popups from the map the map widget has no problem displaying the hosted, view details.
With some testing I determined at about 82/83k is when the widget no longer works.
I created a view of parcels of around 81k records and I am able to get details through the featureinfo widget.
I then recreated the view with just over 83k records and then the widget fails.
I have attached an image that shows the popup from the view with the details and the featureinfo widget with just the generic message.