Timeout joining big remote rooms

[shyrwall]

Sorry for filing a support request but I can't join #synapse because of this problem.

Tried looking at other issues. Some are old with fixes (which obviously does not apply here since the fixes are included) and others don't really have an answer or are closed without resolve.

When joining (preview works) for example #synapse:matrix.org after a while this appears in the logs,

2023-11-24 12:08:48,322 - synapse.replication.http.membership - 89 - INFO - POST-19608 - remote_join: @zib:xmr.se into room: !ehXvUhWNASUkSLvAGP:matrix.org
2023-11-24 12:08:48,767 - synapse.http.matrixfederationclient - 348 - INFO - POST-19608 - {GET-O-1935} [matrix.org] Completed request: 200 OK in 0.45 secs, got 514 bytes - GET matrix-federation://matrix.org/_matrix/federation/v1/make_join/%21ehXvUhWNASUkSLvAGP%3Amatrix.org/%40zib%3Axmr.se?ver=1&ver=2&ver=3&ver=4&ver=5&ver=6&ver=7&ver=8&ver=9&ver=10&ver=11
2023-11-24 12:09:26,428 - synapse.http.matrixfederationclient - 348 - INFO - POST-19608 - {PUT-O-1937} [matrix.org] Completed request: 200 OK in 37.66 secs, got 49098167 bytes - PUT matrix-federation://matrix.org/_matrix/federation/v2/send_join/%21ehXvUhWNASUkSLvAGP%3Amatrix.org/%24RTRSjwHh4xBZVO5gche9Ri3sj_yLKESeifa1C4CYrEs?omit_members=false
2023-11-24 12:13:52,344 - synapse.http.client - 932 - INFO - POST-9058 - Error sending request to  POST synapse-replication://master/_synapse/replication/remote_join/%21ehXvUhWNASUkSLvAGP%3Amatrix.org/%40zib%3Axmr.se/XGkCQlkQMB: RequestTimedOutError 504: Timeout waiting for response from remote server
2023-11-24 12:14:07,398 - synapse.http.server - 124 - INFO - POST-21356 - <SynapseRequest at 0x7fce7d068210 method='POST' uri='/_synapse/replication/remote_join/%21ehXvUhWNASUkSLvAGP%3Amatrix.org/%40zib%3Axmr.se/XGkCQlkQMB' clientproto='HTTP/1.1' site='9093'> SynapseError: 500 - Internal server error
2023-11-24 12:14:07,398 - synapse.http.server - 776 - WARNING - POST-21356 - Not sending response to request <SynapseRequest at 0x7fce7d068210 method='POST' uri='/_synapse/replication/remote_join/%21ehXvUhWNASUkSLvAGP%3Amatrix.org/%40zib%3Axmr.se/XGkCQlkQMB' clientproto='HTTP/1.1' site='9093'>, already disconnected.
2023-11-24 12:14:07,411 - synapse.http.client - 923 - INFO - POST-9058 - Received response to POST synapse-replication://master/_synapse/replication/remote_join/%21ehXvUhWNASUkSLvAGP%3Amatrix.org/%40zib%3Axmr.se/XGkCQlkQMB: 500
2023-11-24 12:14:07,423 - synapse.access.http.8086 - 465 - INFO - POST-9058 - ... - 8086 - {@zib:xmr.se} Processed request: 319.213sec/0.000sec (0.007sec, 0.000sec) (0.003sec/0.050sec/10) 55B 500 "POST /_matrix/client/v3/join/%23synapse%3Amatrix.org?server_name=matrix.org HTTP/1.0" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Element/1.11.50 Chrome/118.0.5993.89 Electron/27.0.2 Safari/537.36" [0 dbevts]

Client error : MatrixError: [500] Internal server error (https://xmr.se/_matrix/client/v3/join/%23synapse%3Amatrix.org?server_name=matrix.org)

Increasing client_timeout under federation does not seem to help.

Thank you

[erikjohnston]

For joining big rooms the request does sometimes time out, but eventually completes in the background. Did the room eventually appear in your client?

[shyrwall]

After timing out and the client showing the internal server error it goes back to the room preview mode and stays there.

Edit: For note, probably irrelevant, the room preview shows the title and latest version of synapse to be 1.88.0 so i'm not sure how the preview works since it's not up to date.