On 2017-03-23 09:14:07 +0800, Craig Ringer wrote: > On 23 March 2017 at 07:31, Andres Freund <and...@anarazel.de> wrote: > > On 2017-03-23 06:55:53 +0800, Craig Ringer wrote: > > >> I was thinking that by disallowing snapshot use and output plugin > >> invocation we'd avoid the need to support cancellation on recovery > >> conflicts, etc, simplifying things considerably. > > > > That seems like it'd end up being pretty hacky - the likelihood that > > we'd run into snapbuild error cross-checks seems very high. > > TBH I'm not following this. But I haven't touched snapbuild much yet, > Petr's done much more with snapbuild than I have.
We can't just assume that snapbuild is going to work correctly when it's prerequisites - pinned xmin horizon - isn't working. > We're not going to have robust logical replication that's suitable for > HA and failover use on high load systems until 2020 or so, with Pg 12. > We'll need concurrent decoding and apply, which nobody's even started > on AFAIK, we'll need sequence replication, and more. These seem largely unrelated to the topic at hand(nor do I agree on all of them). > So I'd really, really like to get some kind of HA picture other than > "none" in for logical decoding based systems. If it's imperfect, it's > still something. I still think decoding-on-standby is simply not the right approach as the basic/first HA approach for logical rep. It's a nice later-on feature. But that's an irrelevant aside. I don't understand why you're making a "fundamental" argument here - I'm not arguing against the goals of the patch at all. I want as much stuff committed as we can in a good shape. > What do _you_ see as the minimum acceptable way to achieve the ability > for a logical decoding client to follow failover of an upstream to a > physical standby? In the end, you're one of the main people whose view > carries weight in this area, and I don't want to develop yet another I think your approach here wasn't that bad? There's a lot of cleaning up/shoring up needed, and we probably need a smarter feedback system. I don't think anybody here has objected to the fundamental approach? Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers