Hi! During my continued experiments with caching I discovered something surprising. • I have a mapped task with two inputs - one is unmapped, the other one returns a list over which I map • all those tasks have caching enabled and use LocalResults • dummy cache_validator prints current inputs to the task and also cached inputs extracted from cached state • when executed locally it works fine - all cached_inputs are correctly populated • when executed using prefect-server only one input is populated - for the other one the input is present in the dictionary, but the value is None To keep this post brief I'm gonna put all of the details in the thread

Hey @Krzysztof Nawara, Thank you for all of these details! Based on this information, most particularly the lack of a LocalResult location for your

mapped1

task, this is starting to smell like a bug. Of course, I may be overlooking something here as you were able to successfully run this with Core only and started to see issues when implementing with Server. Would you be willing to open an issue on this with the above information to get more visibility with the devs? I'm happy to assist here if needed.

Sure! Here https://github.com/PrefectHQ/server/issues or here https://github.com/PrefectHQ/prefect/issues ?

Really great question given the peculiarities you are seeing. Also, I just noticed you are using Prefect 0.12.2 for this flow - so we may want to check this caching behavior with the latest version of Prefect just in case. There have been many improvements since then - latest version is 0.13.11.

Makes sense, I should've thought about that 🙂 I'll check it and let you know

Gotcha, if this is still occurring and everything above still applies then a Core issue for sure is warranted!

Okay, I'll get my ducks in a row and then raise it against core