How do lemmings update their cache of federated communities@instances? (lemmy.world)

submitted 1 year ago by [email protected] to c/[email protected]

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I am trying to find a home base lemmy that I jive with that is a bit smaller and less likely to get crushed. While exploring I have found disparities in which foreign communities I can search for and find. Most of the time I can't find the community I know exists, or I do find and the User count is so wildly off that I question if I have found the correct one(I have).

It seems to me that the communities@foreignInstance are irregularly/periodically updated into a local cache. If I am correct can Lemmy servers at least expose 'Last Update time', 'Next Update time' and just general mean time between updates?

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[-] [email protected] 8 points 1 year ago* (last edited 1 year ago)

There's 3 very different scenarios. I'll use server1 and comm@server2 to illustrate

Nobody on server1 is subscribed to comm@server2. Until and unless someone searches/subscribes in the community page for the full URL (https://server2/c/comm), nothing from that community is pulled in at all, and going to the link results in a 404 community not found error.
Somebody on server1 searched for comm@server2, but did not subscribe. A few of the top posts are pulled in, but nothing too heavy. The comments & votes are not guaranteed to be accurate.
Somebody on server1 subscribes to comm@server2. Every post, comment and vote from that point forward is pulled in, the user counts will normalize, and generally after a few hours it'll look the same (except for some missing historical posts from before the subscribe).

Does that answer your question? Happy to clarify further if needed.