Thanks. I'm still learning about Vespa, and it's still not clear how map fields work.

Edit: Documentation says: "Accessing attributes in maps and arrays of struct in ranking is not possible". So maps aren't really usable.

Regarding how long it takes to update a field, the application I described would have to do this programmatically. It would have to keep track of all known fields in some kind of registry, and then if a new unknown field came in, it would have to perform an "application package" deploy just for that field, using the REST API. (Unless there's a less cumbersome way to do it?)

Reference docs: That's nice, but that's just a bunch of links. Good reference documentation has tables of contents. Bonus points for runnable examples in multiple languages. For an example of good reference API documentation, look at Stripe's [1].

[1] https://stripe.com/docs/api