[Bug]: Missing posts, Communities not showing all posts

[mermit]

Requirements

• Is this a bug report? For questions or discussions use https://lemmy.ml/c/lemmy_support
• Did you check to see if this issue already exists?
• Is this only a single bug? Do not put multiple bugs in one issue.
• Is this a backend issue? Use the lemmy-ui repo for UI / frontend issues.

Summary

Posts are missing on some communities, for example:

• https://lemm.ee/c/[email protected] shows only 2 posts, (UI: 0.18.1-rc.11, BE: 0.18.1-rc.10)
• https://lemmy.ml/c/citiesskylines also shows only 2 posts, (UI: 0.18.1-rc.11, BE: 0.18.1-rc.10)
• but https://lemmy.ca/c/[email protected] shows "all" posts, (UI: ?, BE: 0.18.0)
• and https://lemmy.world/c/[email protected] too. (UI: 0.18.1-rc.10,
  BE: 0.18.1-rc.9-14-ge71951309)

Other users also seem to be having the same issues: https://lemm.ee/post/737999

Steps to Reproduce

1. Go To https://lemmy.ml/c/citiesskylines, only showing 2 posts
2. Go To https://lemmy.world/c/[email protected], showing all expected posts

Technical Details

Affected instances are running UI: 0.18.1-rc.11, BE: 0.18.1-rc.10.

Could possibly be a UI error too, however the same thing happens on the Memmy IOS App

Version

BE 0.18.1-rc.10

Lemmy Instance URL

lemm.ee, lemmy.ca

[dessalines]

This is due to a filter I added to massively improve performance of the active and hot sorts. I'll have to revert it unfortunately I think.

[wereii]

UI: 0.18.1-rc.11
BE: 0.18.1-rc.10

Can confirm the same problem. This community has been first visited on the versions specified.
https://biglemmowski.win/c/[email protected]

Additionally seeing unsynced posts again.
Edit3: Moved these notes into comment in #3525

[finnim]

I can confirm that this also causes pinned posts to disappear.

If I remember correctly, the way reddit calculated "hot' was to give a weight to the score and a weight to the newness of a post. The older it got the lower its hotness due to age becoming an exponentially negative multiplier. With such a formula it should be possible to calculate a hot score without having to filter.

[Shatur]

@Nutomic I recently posted this post to game development. But the post is missing if you click in the community (just click on it from the post). Is this this same bug, or should I open a separate issue?

[mermit]

@Shatur I can see it from the community itself (not logged in on lemmy.ml tho). Is it possible that you have “show read posts” turned off?

[Shatur]

Oh, I just tried it again and I can see it now too.
That's odd, the post was missing yesterday and before writing my message here. Also, the post didn't show up on my profile before (I had only two posts in my profile, now I can see all of them).

[Shatur]

Oh, I know what happening. I changed languages to "Undefined". This is why most posts were missing.
Surprised that it also affects my own posts. Sorry for the mess.

[mermit]

Oh! So that’s what happened. And no worries we both learned something from it. Also am happy that it is not an inconsistent bug