Not the author, but I've used PG like this in the past. My criteria for selecting a job was (1) the job was not locked and (2) was not in a terminal state. If a job was in the "processing" state and the worker died, that lock would be free and that job would be eligible to get picked up since its not in a terminal state (e.g., done or failed). This can be misleading at times because a job will be marked as processing even though its not.
