Why does /All show different posts in different instances?
Like many others, I created accounts on a few different instances to try things out. Using apps like Liftoff and Jerboa make it very convenient to switch between accounts, but I’ve noticed that I get different posts showing up when browsing All, even with the same sort settings.
Can someone explain why that would be? I don’t think any of the instances I’m on are defederated, so shouldn’t I see the same posts across different instances?
Imagine 5 instances, all federated with each other. That means each instance maintains one connection to each of the other 4 instances, and there are 25 connections in total.
One of those instances is bigger than all of the other four combined, and it’s struggling to keep up. In one 5-minute window, there are 300 messages to send to each of the other servers, or 1200 messages. These messages are all of new posts, new subscriptions, new commenta, new up/down votes, new edits, new deletes, and new mod actions. The server only has resources to send maybe 800 or 1000 messages to the other four instances, so the last 200 get queued.
And then the next 5-minute window opens with 1200 MORE messages. Except we still have the 200 messages from that last window to clear. Evertthng else being equal, at the end of THIS window we might have 400 messages queued. So on and so forth, more messages get queued and the goal posts recede faster than the speed of light. Eventually the server runs of of queue, and messages (at best) get dropped. Ultimately tjenserver crashes and restarts and those messages in the queue get lost. (There’s an announcement on the main page)
Lemmy.world.is that big server, and its subscriber instances are getting inconsistent updates because Lemmy.world’s server is resource starved from the massive influx of new users and traffic this weekend.
Have patience. It’ll smooth out, but it will take time.
I’m not certain, but part of it would depend on what instances you’re talking about. For example, Beehaw defederated from .world and shit just works, so /all is going to look a lot different from those three.
All timeline is all post from subs/community that you and your instance-mates subscribe. Each instance has different users, and different user follow different communities. Hence All timeline can be different for each instances.
I read an instance will only mirror content after an user requests it, so different people may have different requests.
for example if I want to follow a community about gardening on lemmy world, and nobody else from my instance is following content from lemmy world, then my instance doesn’t show lemmy world- until I subscribe to a community. Once I do, my instance will start receiving lemmy world content, and everyone else from my instance will be able to see lemmy world (even if they dont follow anything there) if they browse All.
The All timeline shows posts from communities that have at least one user from that instance subscribed to them.
If no users from instance A are subscribed to community X, this community will never show up in that instance’s All timeline.
This is because otherwise instances have no idea what communities are out there. It isn’t until a user subscribes to a remote community that the instance starts receiving posts for that community and learns that it exists.
When a user subscribes to a remote commmunity, the remote instance starts sending updates for content that’s newly created for that community and the user’s instance knows it exists and is able to display that received content in the ALL timeline.
Not every instance communicates with every other instance in existance. Some instances ‘know about’ other instances while other instances do not. One instance has to interact with another directly first for them to discover eachother. This is a problem for smaller instances that don’t have as much cross interaction going on. Also some instances are blocked such as nsfw depending on the admins set rules for aggregation.
I’m not too knowledgeable on this but I imagine the servers update content or ingest content from other servers at different rates. Some larger instances are under heavy load and some instances may be running older/newer versions of Lemmy.
Do admins have any say in how content is ordered in the feed? I don’t know at all.
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