How can I change the serialization method used by the Python multiprocessing library? In particular, the default serialization method uses the pickle
I believe the patch you're referring to works if you're using a multiprocessing "context" object.
Using your pickle2reducer.py, your client should start with:
import pickle2reducer
import multiprocessing as mp
ctx = mp.get_context()
ctx.reducer = pickle2reducer.Pickle2Reducer()
And ctx has the same API as multiprocessing.
Hope that helps!