Description

After updating to Synapse 1.63.0 today, one of my Synapse instances experiences a noticeable performance regression:

According to the metrics (snapshot at https://fsr-ops.cs.tu-dortmund.de/dashboard/snapshot/PyUD0nsC3zYGM3AyCOrwWOOWTbdRsXZo?orgId=0) handle_new_client_event and action_for_event_by_user now consume significantly more CPU and database resources.

#13100 and #13078 seem to have touched these functions for 1.63, so maybe they are the culprit?

Steps to reproduce

• Update to Synapse 1.63.0
• Observe worse performance in Grafana

Homeserver

fachschaften.org

Synapse Version

1.63.0

Installation Method

Docker (matrixdotorg/synapse)

Platform

Docker on Ubuntu 20.04 in LXC

Relevant log output

I didn't see something relevant in the log output (and there is just too much to paste everything) and the Grafana snapshot is hopefully more helpful than a huge amount of logs.

Anything else that would be useful to know?

No response