Re: standby registration

Josh Berkus <josh@agliodbs.com> writes:
>>>> Quorum commit, even with configurable vote weights, can't handle a
>>>> requirement that a particular commit be replicated to (A || B) && (C
>>>> || D).
>>> Good point.

So I've been trying to come up with something manually and failed. I
blame the fever — without it maybe I wouldn't have tried…

Now, if you want this level of precision in the setup, all we seem to be
missing from the quorum facility as currently proposed would be to have
a quorum list instead (or a max, but that's not helping the "easy" side).

Given those weights: A3 B2 C4 D4 you can ask for a quorum of 6 and
you're covered for your case, except that C&&D is when you reach the
quorum but don't have what you asked. Have the quorum input accept [6,7]
and it's easy to setup. Do we want that?

> If not, it seems like standby registration is not *required* for 9.1.  I
> still tend to think it would be nice to have from a DBA perspective, but
> we should separate required from "nice to have".

+1.
--
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support