When MapReduce command outputs to a temp DB, it will fail due to unauthorization error. This is because the output DB of MapReduce is not the same as the one I issue the MapReduce command on, DBPort will not be able to authenticate against the output DB.

I've figured out a workaround that I have to add a method to DB class to enforce authentication, such that before sending out the MapReduce command, I can ensure my temp DB is authenticated for that connection. But this is not ideal, as the client shouldn't need to deal with all these complexities.