Thanks, yeah. I think strong prefiltering is pretty much always doable because, if nothing else, I usually know the time range of the relevant emails and probably the sender/recipient or some keywords, plus I know how to filter out a big chunk of the irrelevant emails (like mailing lists, etc.), so I'm hoping it's not actually that much data for each search. What I don't know is which models would be most suitable even in the case where I can fit the data.

As an example of the kind of query I'm interested in, I want a model that can tell me all the flights I took within a given time range (so that means it'd have to filter out cancellations). Or, for a given flight, the arrival and departure times and time zones (or the city and country so I can look up the time zone). Stuff like that. (Travel is just an example obviously, I have other topics to ask about.) It's not a terribly large number of emails to search through in each query, but the email structures are too heterogeneous across senders to write custom tooling for each case.