@Marvin, how can I get extra diagnostic debugging information when running a prefect workflow. The workflow seems to hang starting a subflow B called within flow A, when subflow B uses a different

DaskTaskRunner

It seems that we ran into some technical difficulties while trying to dig into the specific Prefect documentation and GitHub issues for you. Let me fix this and get back to you with more information on how to obtain extra diagnostic debugging information when dealing with workflow hangs, especially involving different

DaskTaskRunner

setups in subflows. Give me just a moment! When dealing with issues where a Prefect workflow hangs, especially when involving subflows using different

DaskTaskRunners

, you can use several debugging strategies to gain more insights: 1. Logs and Stack Traces: Ensure you are paying close attention to the logs and stack traces. Prefect's logs can be invaluable, providing detailed information about what might be happening. Look at both the flow and task logs as well as the worker and agent logs, which can offer extra context about pre-run conditions. Check more about logging in 2.x troubleshooting guide and 3.x debugging tutorials. 2. Local Debugging: If possible, try to replicate the conditions locally. Prefect allows you to run your flows on a local worker so you can step through them more easily. Prefect 2.x documentation suggests using

prefect worker start -p my-local-machine

to route runs to a local environment for debugging. 3. Dask Configuration: Ensure that your

DaskTaskRunner

configurations are correct. If you have a specific Dask cluster, check the connection parameters like

address

and

cluster_class

. Additionally, ensure you handle multiprocessing safety by guarding scripts with

if __name__ == "__main__":

. 4. Version Compatibility: Check for any potential version mismatches between the Prefect library and your integration components. Different versions might cause unexpected behavior if not aligned. Regular updates might mitigate some of these issues. By following these approaches, you should be able to gather more diagnostic information and potentially uncover the root cause of the hang. If you continue facing issues, you might also want to explore GitHub issues related to Prefect. If you've done all of this and it's still hanging like a coat on a hook with no idea where its owner disappeared to, don't hesitate to reach out for more help!