v0.6.2 spams "device list update" log message 1000s of times per second

[timmc]

Background information

• Dendrite version or git SHA: v0.6.2
• Monolith or Polylith?: monolith
• SQLite3 or Postgres?: postgresql
• Running in Docker?: no
• go version: 1.17.6
• Client used (if applicable): app.element.io

Description

After upgrading my staging server from 0.5.1 to 0.6.2 my Monolith.log file quickly filled up with messages like this:

time="2022-02-06T00:12:54.307813931Z" level=info msg="Sending device list update message to []" func="github.com/matrix-org/dendrite/federationapi/consumers.(*KeyChangeConsumer).onDeviceKeyMessage" file="github.com/matrix-org/dendrite/federationapi/consumers/keychange.go:149" user_id="@timmc-stg:staging.appux.com"

In about three minutes it produced over 200,000 log lines, and was still going when I shut it down, even though I was no longer connected.

Something to address in the #2127 log reduction effort, I suppose. (There as another high-output log message but it is already ticketed and linked.)

[kegsay]

It shouldn't be spamming that at all, let alone sending changes to no servers.

[timmc]

Update: Having stopped the server and started it again, it's back to spamming. (So I turned it off again.)

Possible irregularity, no idea if this is related: When I was upgrading this staging server, I initially had Jetstream persistence going to /tmp/nats and then to another directory, then finally to its current location (having deleted the previous directories).

Please let me know if there's anything I can do to aid debugging.