In reply to@smar:yuuko.smar.fi
but can’t that data just be kept in memory? it shouldn’t take too many bytes, if all that data contains is just user ids and permission bits

The room state is not just user IDs and permission bits, it's a directed acyclic graph containing which server did which modifications to the room state and when, because different servers can update it at any time they want and there needs to be some way for all servers to resolve the room state into a single consistent view of "the truth"

In reply to@flux:matrix.org
vurpo: how much of that graph is typically traversed when updating the state, though?

In reply to@smar:yuuko.smar.fi
I get it that you need to write everything somewhere where the data doesn’t get lost, but something feels off here... but again, I’m in no means versed in how matrix works :)

In reply to @vurpo:hacklab.fi

The room state is not just user IDs and permission bits, it's a directed acyclic graph containing which server did which modifications to the room state and when, because different servers can update it at any time they want and there needs to be some way for all servers to resolve the room state into a single consistent view of "the truth"

In reply to @dandellion:dodsorf.as
if you are a homeserver admin shift click it in the directory

In reply to@ssorbom:matrix.org
Out of curiosity, how is the truth actually enforced though? What's to stop a malicious server being part of a room and then claiming that certain events happened at a time that they didn't happen? Or claiming that certain administrative actions we're taken that were not?

All servers have to sign everything they send out by their own signing key, so:

A server could not say that other servers' users did something because it can't sign the events with those servers' keys

It couldn't claim that its own users did something forbidden because all other servers will just say "no, that can't happen because that's not allowed". If the malicious server keeps living in its own alternate reality where those events did happen, then it would also be living in a detached reality where it can't communicate with other servers because they don't agree on what reality is

In reply to @x:riot.ovh
It could only claim that to its own users, or if it's users in that room had administrative privileges

A server can indeed tell its own clients whatever it wants, because those clients don't receive information from anywhere else

But it can't tell other servers that "my server's user X is now the admin of this room btw", because other servers will just say "that's not right" and then ignore it