[meta] Improving Presence Performance

[anoadragon453]

Presence is a feature of matrix that allows users to share their online/offline/unavailable status with other remote and local users, as well as present a status message. Traditionally this feature has been turned off in all major deployments due to its enormous performance costs. We'd like to turn it back on, and this issue is a collection of other issues that may help us get there.

There is currently no timeline for these tasks.

• Presence logic for handling newly joined rooms is very inefficient and does duplicate work #8956 (fix #1)
• Synchrotrons always wake up sync streams for presence updates #8955
• Not all presence updates should be sent out over federation immediately. #9415
• Stop sending unneeded presence messages #9339
• Moving presence work off of the master process done in Move presence off master #9761

[richvdh]

See also #3971

[Beryesa]

Will there be any fundamental changes on this for matrix 2.0?

[anoadragon453]

@Beryesa presence performance is not one of the goals of Matrix 2.0. Please see the Matrix 2.0 blog post for everything it does cover.

Matrix 2.0 is improving some large parts of the spec and implementation, but it isn't the only thing being worked on by the Matrix core team or community. Other work is happening in parallel. So just because Matrix 2.0 doesn't have a certain stated goal, doesn't mean it isn't on somebody's plate :)

[Beryesa]

@richvdh I wondered if the new lazy-loading room state could improve the situation for presence as well. I guess not. Thanks!