Quick video demonstrating that lemmy.world sends every activity out twice
I realise this is a known issue and that lemmy.world isn't the only instance that does this. Also, I'm aware that there are other things affecting federation. But I'm seeing some things not federate, and can't help thinking that things would be going smoother if all the output from the biggest lemmy instance wasn't 50% spam.
Hopefully this doesn't seem like I'm shit-stirring, or trying to make the Issue I'm interested in more important than other Issues. It's something I mention occasionally, but it might be a bit abstract if you're not the admin of another instance.
The red terminal is a tail -f of the nginx log on my server. The green terminal is outputting some details from the ActivityPub JSON containing the Announce. You should be able to see the correlation between the lines in the nginx log, and lines from the activity, and that everything is duplicated.
This was generated by me commenting on an old post, using content that spawns an answer from a couple of bots, and then me upvoting the response. (so CREATE, CREATE, LIKE, is being announced as CREATE, CREATE, CREATE, CREATE, LIKE, LIKE). If you scale that up to every activity by every user, you'll appreciate that LW is creating a lot of work for anyone else in the Fediverse, just to filter out the duplicates.
Could it be something to do with an instance running multiple servers, i.e. for horizontal scaling? Maybe there's some configuration problem where two servers are sending out the federation rather than just one.
Obviously if you only run one lemmy process (which I think most smaller instances do) then it's not a problem. But if you run more (which I'd assume lemmy.world does) then it could perhaps be the reason.
EDIT: Probably should've checked your links first as that seems to be exactly what is happening lol
I'm only running one process, I'd assume the problem isn't happening for Feddit.dk.
Perhaps. The lemmy.ca post has a comment in from the mander.xyz admin who's only running one, and there's a new comment in this thread saying mander.xyx is one of the instances they see the most duplicates from.
Sounds like there might be a bug in Lemmy then. Please open an issue in the Lemmy repo.
okay
Yeah, that's the conclusion I came away with from the lemmy.ca and endlesstalk.org chats. That's it due to multiple docker containers. In the LW Matrix room though, an admin said he saw one container send the same activity out 3 times. Also, LW were presumably running multiple containers with 0.18.5, when it didn't happen, so it maybe that multiple containers is only part of the problem.
I'm not surprised that it changed from 0.18.5 as the way that you spread the federation queue out changed significantly from that version to 0.19.
All the information is here but if you just run the same configuration as before 0.19, then you will have trouble.