Index most/all data up front and introduce retroactive reporting for session activity (e.g: an error actually being displayed to the user and not just the text being in the page response). This can be for a shorter time: 7 days, 14 days, 30 days, other. 49 out of 50 time for people asking for data they want it from the past, which with SPA's it's pretty much impossible to get unless there was already an event counting the conditions.

The utility to upload sessions to canisters and analyze could possibly be leveraged for this, at least partially. It should be on-demand reporting only and not added to existing "live" reporting. I'm picturing something similar to how a cxConnect batch extract works currently, but it would reanalyze all events I(or selected events) against the session data for a search result set.