Is Mastodon eventaully consistent?
I've yet to make an account on Mastodon and I'm wondering, how good are its consistency guarantees? Do posts get lost? Will they eventually get to all federated instances?
From my Lemmy experience, posts do get lost here, from time to time. Is it the same on Mastodon?
6 replies
I would say it depends on what you mean by eventually consistent. The simplest answer is that it has consistency insofar as databases and various queue technologies have consistency. That doesn’t account for the edge cases of federation and deletions of accounts/communities.
Sure, I mean consistent in the following sense: will updates be eventually propagated even if the receiving server is throwing errors and/or is unreachable for some time? Do servers sync up?
Yea, so my understanding is that activity pub, the protocol used by mastadon (and lemmy) is serviced by queues, perhaps those like Kafka. Those sort of queues promise eventual consistency, which means when one goes offline, the queue is stored on the other, waiting until the other is online, in which case it resumes where the disconnected server last left off.
In principle, yes. Lemmy, for now, only stores updates in memory, so if something goes wrong, they can easily go missing. How does Mastodon do it? I guess I'm asking about the implementation. I'm not familiar with Ruby...
Ahh, I can’t help with actual implementation. Sorry!
TIL Mastodon doesn't compress its API responses... And I was complaining about Lemmy's verbosity...