Multiplayer song selection does not save state and is slow with a lot of maps loaded

[IceDynamix]

Type

Game behaviour

Bug description

Issue:

• I have about 16000 mapsets / 62000 maps loaded into lazer and loading the song select in multiplayer takes multiple seconds on every load
• Search filters or selected collections are not saved across multiple selections

Expect:

• Song select to load instantly like when starting the game and playing singleplayer
• Search filters and selected collection to be kept when selecting another map in multiplayer

Reproduce slow load:

1. Load a large number of maps
2. Open a multiplayer room
3. Select a map and wait for the maps to load

Reproduce unsaved search/collection:

1. Open a multiplayer room
2. Select a map with a search filter or a selected collection
3. Select another map, observe cleared search filter or

Extra:
I think both issues can be solved in the same fix, hence putting both into a single issue.

Screenshots or videos

Slow load

osu._2022-12-30_18-08-35.mp4

Search filter or selected collection not saved across map selections

osu._2022-12-30_18-09-06_.mp4

Version

2022.1228.0-lazer

Logs

database.log
input.log
legacy-ipc.log
network.log
performance.log
performance-audio.log
performance-draw.log
performance-input.log
performance-update.log

[bdach]

This is happening because in single-player a single song select instance is preloaded at main menu, while online gameplay flows push new screen instances every time.

I guess a similar preload solution could be applied to multiplayer, although I'm not sure if it's going to be smooth sailing.

[peppy]

@bdach for some context on how i originally saw this working: screens like song select would only be instantiated once by the game, ie. we would have the ability to "suspend on exit" and then resume from this state.

If that's not feasible or seen as a good direction, then it will make sense to create a higher level component that manages the realm subscriptions so we don't have to re-query / reconstruct each time song select is loaded.