Application for the tournament in advance: The rating remains unchanged in the table with rating changes.

[Tevajs]

Exact URL of where the bug happened

lichess.org

Steps to reproduce the bug

Sign up early for the tournament. Play games for rating. In the tournament, your rating will not change.

What did you expect to happen?

Rating must change

What happened instead?

Rating remains the same as at the time of application

Operating system

Windows 11

Browser and version (or alternate access method)

Google Chrome 112.0.5615.138

Additional information

https://lichess.org/forum/lichess-feedback/lichess-bug-3-wins-in-profile-minus-in-rating
My forum bug report.
Side effects from this are also attached

[Diordany]

I reproduced the bug on my local Lichess build:

The first match was played outside of the tournament, after both user1 and user2 applied for the tournament. The rating of user1 would go from 1638 to 1729, but the rating is still 1638 at the beginning of the first match of the tournament (as @Tevajs points out). However, at the start of the second match of the tournament, the rating is correct again as it would've gone from 1729 to 1772 in the match before.

To summarize: the rating only appears to be incorrect for the first match of the tournament (second match in the picture).

[kraktus]

Hello,

For more context, it's been like that for years to avoid stressing the db when starting a big tournament (imagine a marathon with 20k users to update their rating just before the start). However with the recent change in user_perf it's possibly less expensive.

The issue would be to do it efficiently and also stress test the change before going live, so not easy.

[Tevajs]

Well, about the decision: you can't play any games after you signed up for a tournament on chesscom.

[DrSteinbot]

Just from a performance standpoint wouldn't it more efficient to update the players rating in the listing after he played a game, so that the players who aren't playing won't be the server and the ratings wouldn't be pulled all at the same time