this post was submitted on 21 Dec 2023
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Performance does seem to have improved somewhat now, but is anyone else having problems with federation or is it just me?
Some of my posts and comments in remote communities just don’t seem to be showing up anywhere else but here. I checked the modlog on the remote instance to make sure I’m not banned there, but I’m not. Post is still not showing up there though.
This seems very related to the update of Lemmy software to 0.19.1.
There was a critical bug with outgoing federation in 0.19 that was supposed to be fixed in 0.19.1:
https://join-lemmy.org/news/2023-12-20_-_Lemmy_Release_v0.19.1_-_Outgoing_Federation_fix
I would say it seems the bug is not fixed...
Well, interestingly enough, all of my posts and comments from the last 24 hours DID just show up on those remote instances.
Not sure if you made any changes to the configuration, but if you did, it seems to be working.
I did a restart of Lemmy software just now, so I guess that made federation start to work again. But Im worried now it will stop again at any time. Will post a question in AskLemmy and see if anyone else has similar issues.
Ah, so perhaps there was a backlog in the database and the server wasn’t processing it for some reason?
But yes I agree, the 0.19 release seems to have quite a few issues. Other instances have seen similar problems ever since the upgrade.
Yeah I think the way outgoing federation works now in 0.19 has been rewritten to use a queue. So no comments or posts should ever be lost with this design, but there seems to be a bug causing the software to not process that queue sometimes I guess.
Well, as long as a restart can get it to work again that’s at least something, but let’s hope the devs manage to find a more permanent fix.
Back in the era of FidoNet and federated BBSes in the 1980s, it used to be that a number of BBS forums would only forward messages at night to save on telephone costs. I suppose a nightly restart to push out messages would be a bit of a blast from the past.
TFW you accidentally reinvented the wheel again
I don't think that any of my comments on remote communities for the past 22 or so hours prior to this comment, which I assume is when the update happened, are visible on other instances.
Ditto for posts.
I can see material via lemmy.today that remote users are putting on remote communities, though.
Yeah same here. Just looked at my profile on the other instance, and nothing I posted there in the last 24 hours is showing up there.
I can narrow down the time a bit, since I was listening to some audio and transcripting/summarizing it in a comment series, and things broke right in the middle.
My last comment to make it out to another instance looks to be this one, starting with "Bergman: Michael, I want to turn to you":
https://lemmy.today/comment/4228981
Visible on the remote instance as this:
https://kbin.social/m/Ukraine_UA/t/716867/Aid-to-Ukraine-and-the-Future-of-the-War-with#entry-comment-4244549
The first to fail to propagate -- to that same instance -- was the response to that, starting with "Bergman: Michael, I think there’s another"
It's also not just the kbin.social instance; other instances like sh.itjust.works also are affected, to rule out it being a kbin.social problem.
EDIT: Both the sh.itjust.works instance federation list and the lemmy.today instance federation list show the other instance as being federated:
https://lemmy.today/instances
https://sh.itjust.works/instances
EDIT2: I don't think that there's much else beyond what I've written above that I can do from a troubleshooting standpoint as a non-admin user -- but if there is, feel free to let me know, @mrmanager.
Yeah, for me it is Lemmy.world and Lemmy.ml. The latter is also running on 0.19.1, and the former is still on 0.18.5, so the remote server software or version does not seem to be a factor here.
Oh, that's a good point. We can see server versions elsewhere.
Here's a comment from @nutonic@lemmy.ml, one of the lemmy devs, to a remote community on lemmy.world:
https://lemmy.ml/comment/6801426
https://lemmy.world/comment/6173591
That comment appears to have propagated.
While I cannot say for certain that at that point lemmy.ml had already updated to 0.19.1, it was after lemmy.today had, so it seems plausible.
So whatever the problem is, I would lean towards guessing that it does not affect all 0.19.1 instances.
EDIT: Other users are talking about potential federation problems in this thread, where votes appear not to be making it out:
https://lemmy.ml/post/9624005?scrollToComments=true
But as someone there points out, the first two users there put up a comment from a 19.1 instance (lemm.ee and sopuli.xyz), and their comments did make it out.
Well, as I just said here, all my comments and posts from the last 24 hours JUST started showing up on those other instances, so perhaps the problem is fixed now.
Maybe there was some sort of database backlog or something, let’s see what /u/mrmanager says.
I think it was Lemmy software stopping to federate for some reason, and after i did a restart of Lemmy, it federated everything in the queue right away. But its worrying that this can happen, and I assume its a bug somewhere hiding in the software still.
Thanks for looking into this. Let’s hope the devs will get this sorted out eventually.
Oh, thanks for the update!
I can see the comment on kbin now after restart of Lemmy software:
It really seems like outgoing federation is buggy in this version. :/
Thanks!
A warning, though...after your restart, I just commented in that other lemmy.ml thread talking about 0.19 federation problems on lemmy.ml and linked to this thread -- given that you identified an important data point -- and that comment doesn't appear to have propagated. That'll be a comment added to the queue without a restart after the comment was made. Now, it was only 5 minutes ago that I made the comment, so maybe I'm just excessively impatient, but...
The local view of the thread:
https://lemmy.today/comment/4245923
The remote view of the thread:
https://lemmy.ml/post/9624005?scrollToComments=true
My comment text:
Indeed, it hasnt federated. So the restart of Lemmy polls the queue and then it stops working again. :/
I did another restart and your comment shows up in the thread.
So seems to be some bug that makes it stop federating after it has polled the queue once.
Hmmm.
A couple thoughts:
As I commented above, this doesn't appear to be impacting every 0.19.1 instance, so there may be something on lemmy.today that is tickling it (or it and some other instances).
If you decide that you want to move back to 0.18.x, I have no idea whether lemmy's PostgreSQL databases and stuff support rolling back, while continuing to use the current databases, whether there were any schema changes in the move to 0.19.x or whatever.
Something that also just occurred to me -- I don't know what kind of backup system, if any, you have rigged up, but normally backup systems backing up servers running databases need to be aware of the database, so that they can get an atomic snapshot. Like, if you have something that just backs up files nightly or something, they may not have valid, atomic snapshots of the PostgreSQL databases. If you do attempt a rollback, you might want to bring all of the services down, and only while they are down back up the PostgreSQL database. That way, if the rollback fails, it's at least possible to get back to a valid copy of the current 0.19.1 state as it is in this moment.
If all that's old hat and you've spent a bunch of time thinking about it, apologies. Just didn't want a failed rollback to wind up in a huge mess, wiping out lemmy.today's data.
I would like to roll back but the database schema changes would mean having to restore a backup. And potentially end up in more issues just like you were thinking too.
I guess it's best to wait for a fix, and I will also see if I can troubleshoot this myself a bit. I'm guessing it's a database issue since I can see very long running update statements on every restart, and they may not be able to complete for some reason.
Possibly relevant:
https://github.com/LemmyNet/lemmy/issues/4288
This was the bug for the original 0.19.0 federation problems, and admins are reporting problems with 0.19.1 there as well.
The lemmy devs reopened the bug four hours ago, so I'm guessing that they're looking at it. Not sure if you want to submit any diagnostic data there or whatnot.
Thank you, very good to know.
My idea was to try and see what specific query is failing in the database and go from there, so currently enabling logging of failed postgres queries. Hopefully see something in those logs...