---
summary: Changing displayname is catastrophically slow.
---
created: 2015-03-13 20:35:47.0
creator: matthew
description: ''
id: '11229'
key: SYN-311
number: '311'
priority: '1'
project: '10000'
reporter: matthew
status: '1'
type: '1'
updated: 2016-11-07 18:27:50.0
votes: '0'
watches: '6'
workflowId: '11329'
---
actions:
- author: matthew
  body: |-
    Kodo did this ~10 times in a row, each one taking ~180s despite him being in only a handful of channels, and took out matrix.org.

    We need to fix this, *and* do dup suppression on the requests to avoid them stacking up and DoSing the world.
  created: 2015-05-21 18:29:25.0
  id: '11786'
  issue: '11229'
  type: comment
  updateauthor: matthew
  updated: 2015-05-21 18:29:25.0
- author: neb
  body: 'By @kegan:matrix.org: this is a design problem. We need to send an event in every room, we cant get around that. We could maybe draw it out over time so it doesnt block other requests though.'
  created: 2015-05-21 18:59:01.0
  id: '11787'
  issue: '11229'
  type: comment
  updateauthor: neb
  updated: 2015-05-21 18:59:01.0
- author: markjh
  body: |-
    I think this is because updating the display name causes synapse to emit join events for every room the user is in. Whenever synapse emits a join event in a room it broadcasts the presence to every remote server in the room. I think sending the presence per remote server per room is what is causing some of the problems.

    Hopefully this will be improved by https://github.com/matrix-org/synapse/pull/410
  created: 2015-12-03 13:16:04.0
  id: '12424'
  issue: '11229'
  type: comment
  updateauthor: markjh
  updated: 2015-12-03 13:16:04.0
- author: erikj
  body: |-
    [~markjh]: Was this improved?

    Longer term I would like to separate out profile information from joins, and potentially other things to make this nicer.
  created: 2016-01-06 17:56:43.0
  id: '12546'
  issue: '11229'
  type: comment
  updateauthor: erikj
  updated: 2016-01-06 17:56:43.0
- author: leonerd
  body: I'd also be interested to see if this issue was improved by my recent fix to the way server key handling happens - the bugfix where it requeried every remote server every time...
  created: 2016-01-13 20:11:04.0
  id: '12570'
  issue: '11229'
  type: comment
  updateauthor: leonerd
  updated: 2016-01-13 20:11:04.0
- author: richvdh
  body: 'Migrated to github: https://github.com/matrix-org/synapse/issues/1297'
  created: 2016-11-07 18:27:50.0
  id: '13618'
  issue: '11229'
  type: comment
  updateauthor: richvdh
  updated: 2016-11-07 18:27:50.0