Hmm. Maybe? I haven't fully thought through what needs to happen here. I have an expectation that things will change once we start building a workflow around this stuff. For now I just wanted to make sure the threads and znodes get cleaned up.

I think for a "hard kill" this behavior is good. For a "soft kill" (what we'll need when we want to do controlled downtime for a schema change) I think we'll want to start by waiting for the current hour to end, doing the persist-n-merge, and also playing some games with offset-saving so the next job knows where the next hour starts. (It might be earlier than the current hour finished...)