Long fetch time when loading session

[carnal1234]

I've been using fastf1 and noticed that when I call session.load(), it takes a really long time to complete (more than 30 seconds). Not sure if it's normal or if I’m doing something wrong.

session.load(telemetry=True, laps=True, weather=False)

[theOehrly]

FastF1 needs to download multiple megabytes of data for every session. Especially telemetry data is a lot of JSON data (a few hundred thousand lines of JSON) to parse and this is fairly slow. So if you have a slow internet connection and/or a slow machine.

For reference, loading time for the 2025 Monza Race is around 7 seconds for me. That is on a very fast PC with a 1Gbps down link. So 30 seconds of loading time is not unthinkable. It should be noticeably faster after the second run, though, once data is preprocessed and cached locally.

[carnal1234]

Thanks for the tips! Caching and compressing the data definitely seem like good ways to speed things up. I’ll try to set up some local storage and maybe preprocess the data so it loads faster next time. Appreciate the help!

[theOehrly]

FastF1 does caching of the preprocessed data automatically. You shouldn't (need to) do anything extra here. I meant that 30 seconds is fine when loading a session for the first time. But it should be noticeably faster after that. Is that not the case for you?

[carnal1234]

Yeah, The caching work perfectly. I realise that the core issue that is the limited memory of testing server (512MB). So it run out of memory easily... Long runtime is not the biggest problem.