New room takes too long to be created

[kittykat]

Steps to reproduce

1. In the left panel, click + next to the People section
2. In the "Direct Messages" dialog, add two users to start a three way DM
3. "Go" to start the DM

See creation of room !RKRzVogjnVpVWYLVSZ:matrix.org in the rageshake

Outcome

What did you expect?

I can send a message to the new room quickly

What happened instead?

The "Joining room" spinner stuck around for about 30 seconds before I could access the new room

Operating system

No response

Browser information

Chromium 98.0.4758.80 (Official Build) Arch Linux (64-bit)

URL for webapp

develop.element.io

Application version

Element version: a01684e-react-e2827b40825c-js-a89c1990d6f2 Olm version: 3.2.8

Homeserver

No response

Will you send logs?

Yes

[t3chguy]

@kittykat would #14736 be a solution to this for you? If not then its really a Synapse performance issue

[kittykat]

@t3chguy yes, it does. I would be happy if I'm not blocking on the UI to get my messages sent before moving on

[t3chguy]

Closing in favour of #14736 as a proposed solution