Excellent question! But your question seems to make the unfounded assumption that application programmers should be in charge of restoring crashed Actors. Instead, an Actor System should restore Actors as best it can based on recordings that it has. Applications must be made resilient against any and all kinds of inconsistencies that will pervasively arise.
Do you know any resource i could read that would explain how all that is supposed to work out in practice ?
I've never heard of an actor system able to automatically respawn actors with their previous state (the whole system would look like a tree of cached data, each layer responsible for saving the leafs under it, with a huge "persist to DB" on top , wouldn't it ?). Does erlang OTP do those kind of things ?
Edit: also, are you Prof "Carl" Hewitt ? The one that invented actors ? I'd be honored you found a question of mine about actors excellent...
- not all states transitions need to be durable. If performance matters you’ll have to get your actors to call something like a « saveState » from time to time, otherwise every single property change is going to have an overhead in terms of performance.
- what does « durable » mean ? Surely, just having the state of an actor saved in the memory of the supervisor isn’t enough. If the two are on the same server and the server shuts down, it’s game over. You need a « persistence » service / actor, but that thing is going to have to persist the state of all the actors in your system. I don’t see how that can work if you’ve got millions of actors running in parallel.
