Refactor to help with DB deadlocks

[obycode]

During Nakamoto development, we have run into a few deadlocks from accessing databases. I think it would be possible to refactor the code to help prevent these types of deadlocks. There could be some intermediary data structures that ensure locks are obtained in the correct order, etc. I don't have a full design in mind, but I'm sure it can be improved and this seems like a problem that will continue to bite us until we do so.