GET /members is slow, taking >30s to respond for Matrix HQ

[timokoesters]

Description

Element X cannot load the member list because the request times out. Curling the endpoint shows it takes over 30s, in some cases over a minute (on conduit.rs: 23s cold or 4s when cached).

Maybe clients should use /joined_members instead? (Only takes ~2s on matrix.org, 0.7s on conduit.rs)

Steps to reproduce

curl /members for !OGEhHVWSdvArJzumhm:matrix.org

Homeserver

matrix.org

Synapse Version

1.100.0rc1 (b=matrix-org-hotfixes,d5e213e16f)

Installation Method

I don't know

Database

Workers

I don't know

Platform

Configuration

No response

Relevant log output

-

Anything else that would be useful to know?

No response

[anoadragon453]

I can confirm that this endpoint is still slow. Testing it now for @anoa:matrix.org, I saw it take ~1min to respond, then ~32s further seconds to download 47.3MB of JSON.

curl -H 'Authorization: Bearer AUTH_TOKEN_HERE' 'https://matrix-client.matrix.org/_matrix/client/v3/rooms/!OGEhHVWSdvArJzumhm:matrix.org/joined_members' -o members_resp.json

/joined_members was indeed much faster at only ~2s.