On Tue, Sep 26, 2017 at 2:16 PM, Alvaro Hernandez <aht@ongres.com> wrote:
But what about earlier versions? Any chance it could be backported down to 9.4? If that would be acceptable, I could probably help/do that...
The likelihood is zero if you mean backported into core of earlier versions.
Right. We don't add features to back branches.
If you mean backported as a standalone extension that could be installed on a previous version, probably. I'm not sure if it relies on any internals not present before that would make it harder, but it would probably at least be possible.
All the pub/sub stuff is new and hooked into syscache etc. So you'd be doing a bunch of emulation/shims using user catalogs. Not impossible, but probably irritating and verbose. And you'd have none of the DDL required to manage it, so you'd need SQL-function equivalents.
I suspect you'd be better off tweaking pglogical to speak the same protocol as pg10, since the pgoutput protocol is an evolution of pglogical's protocol. Then using pglogical on older versions.