Lemmy Support @lemmy.ml The Baldness @beehaw.org 1y ago

Privacy questions about Lemmy

What information does a Lemmy server collect about its users?

When I delete a comment or post, is it truly deleted on the server?

Do deletions also propagate to federated servers?

43 comments

There is no tracking built into Lemmy, however servers log IP addresses by default.

Posts and comments are not deleted from the server to allow restoring them later. However if you make an edit, it completely overwrites the content. Deleting the user account also deletes all content. Deletions are federated, but because this is a distributed system, there is no guarantee that deletions (or other actions) reach other instances.
Great question, I've noticed post are removed while comments remain but have [deleted] in the comment space. Not too sure what to make of it and curious to see the answer
I'm going to run a quick test and see if I can't answer a couple of those.

Edit:

Results:

I posted two comments to this thread and then deleted one of them. When I checked the database entries corresponding to this post, the comment I deleted is still in the comments table but there is a delete flag set after I deleted it.

So, it appears that deleting a comment just toggles a "deleted" flag in the database. It seems to be intentional as I'm able to undelete the comment from the Lemmy UI.

I deleted and undeleted a post on my own instance, and yes, posts are treated the same: delete flag with the original post still available in the DB.

It's also worth noting that when a comment is removed by a moderator, the comment shows in the modlog. Again, I believe this is intentional.

@TheBaldness (or anyone, really): If you could, can you add a new comment to this post and then delete it? My instance would be a federated one to yours, so I can check the DB to see if it handles federated comments the same as one locally. I'm assuming that it does.
- Comment to delete in a couple of minutes
- I would like to know!
  I'll make another comment and delete it in a couple of minutes
  
  Edit: I deleted the other comment
  
  Interestingly it doesn't suggest it's deleted at all for me. Im using the android Jerboa app so maybe that's why
  
  Is this the comment you deleted? I see it on my own instance in the thread.
- Will do.
- Created a new top-level comment and deleted it.
It seems simliar to how reddit handles it where the comments just get a flag attached to them and the text is still stored. There was some hubbaloo about it a few years ago where people were saying to edit your comments first on reddit before deleting them
- Yeah, that's what it's looking like. It's a bit concerning because the Lemmy devs didn't have to do it that way. They could just mark content as deleted and then zero-out all the fields to default values. I wonder what their reasoning was for not doing it that way.
I'm going to delete this comment.
- Do you still have this comment deleted?
  Or am I seeing it because you restored it?
  
  I restored it and then deleted it again. On my end, it shows "deleted by creator".
  
  Do you still see my original comment?
It is possible that deletions will not propagate to other servers if they are running a forked version of the software.
- Yes, but I'm wondering what the expected behavior is.
I'm going to delete this comment.
- That comment is still showing normally for me and isn't flagged as "deleted" in the DB.
  
  I've had to restart my instance and block a spammy IP. I'm still learning how the rate limits work in lemmy, and my server logs were just flooded with rate_limit_errors for the last 45 minutes or so. Finally just blocked that IP as its traffic pattern didn't match any other Lemmy servers/clients. That said, my server may have missed some announcement messages or something. I dunno.
  
  On another note, I did leave a comment somewhere the other day and deleted it because I realized I sounded stupid. Someone replied to it a day later. I also deleted, restored, and re-deleted a test comment in this thread that someone else said was still visible, so I'm guessing that one of a few things could be the case:
  
  Sometimes comment/post deletions don't federate out/in
  
  There could be something up with my instance
  
  There's some other factor at play.
  
  There's a bug somewhere
  
  I've got to get to bed, so that's as far as I dive into this tonight.
  
  Thanks for working on this!
Nothing on the internet is ever truly deleted. Surely you know this by now?
- Yes, but I want to know what the code actually says, and I probably can't figure it out for myself, so I'm asking.
  
  And there is absolutely nothing wrong with that.

43 comments