I've been reviewing Sijie's patch for BOOKKEEPER-140 and I can't figure out how cross region publication is supposed to work. Perhaps someone on the list can help out. My problem is that I can't see how the guaranteed delivery works.
The delivery guarantee, as I understand it, will guarantee that you will receive all messages, in order, which have been published to a topic, from the point at which you subscribe to the topic. I can see how this works for a single region. However, for more than one region, what should happen if a region A is down when the subscription is created at region B. If the subscription is eventually made to A, should it get all messages from all regions published from the point it subscribed at B, or should it only get them from region A from the point at which the subscription reached region A. Really I guess the question boils down to, how do the message sequence ids between regions interact? Is there any total order between them, or are they completely independent, or a mix of the two? -Ivan
