Millions of `/query/profile` requests

[richvdh]

Over the last hour (in which I did rejoin #element:matrix.org, but still), matrix.org has sent my server 1892 GET /_matrix/federation/v1/query/profile?user_id=%40richvdh%3Asw1v.org requests.

They aren't an inherent problem, since they can be served pretty quickly, but this still smacks of huge inefficiency somewhere.

[clokep]

Tangentially related, but #12966 removed the "remote profile cache", which was only used for groups (the callers were removed in #12558). I wonder if something similar has other uses.

[DMRobertson]

(That's a surprise. I could've sworn the remote profile cache was somehow related to the user directory. Apparently not.)

[turt2live]

I posted a message to HQ (2 if you count edits) and so far I'm at over 1500 requests all of a sudden.

# cat federation_reader_1.log | grep "matrix.org.*query/profile" | wc -l
1650

This sounds like it's related to matrix.org trying to send out push/email notifications or something, failing to cache the sender between notifications.

Currently this is an annoyance on the receiver side, though surely on the matrix.org/remote side it'd be burning a small hole in a bandwidth budget somewhere?