Markus Wanner <markus@bluegap.ch> writes:
> Why does one ever want the guarantee that sync replication gives to only
> hold true up to one failure, if a better guarantee doesn't cost anything
> extra? (Note that a "good alerting system" is impossible to achieve with
> only two servers. You need a third device anyway).
I think you're all into durability, and that's good. The extra cost is
service downtime if that's not what you're after: there's also
availability and load balancing read queries on a system with no lag (no
stale data servicing) when all is working right.
I still think your use case is a solid one, but that we need to be ready
to answer to some other ones, that you call relaxed and wrong because of
data loss risks. My proposal is to make the risk window obvious and the
behavior when you enter it configurable.
Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support