[carterehsmith]

Sounds great in theory.

What we see in reality is that append-only database is unusable without making additional "projections" or whatever you call them, databases that are ready to be queried/updated, with maybe specific denormalizations, indexes and so on.

And oh, btw, those later databases are not "imutable".

[fnordsensei]

It’s structured so that these operations can be done pretty much instantaneously. Schema is sort of asserted at read time, not write time.

I highly recommend the talk “Domain modeling and with Datalog”[1]. It gives an explanation of how all this works, including indexing.

1: https://youtu.be/oo-7mN9WXTw