On 06.10.2010 01:14, Josh Berkus wrote:
> Last I checked, our goal with synch standby was to increase availablity,
> not decrease it.
No. Synchronous replication does not help with availability. It allows
you to achieve zero data loss, ie. if the master dies, you are
guaranteed that any transaction that was acknowledged as committed, is
still committed.
The other use case is keeping a hot standby server (or servers)
up-to-date, so that you can run queries against it and you are
guaranteed to get the same results you would if you ran the query in the
master.
Those are the two reasonable use cases I've seen. Anything else that has
been discussed is some sort of a combination of those two, or something
that doesn't make much sense when you scratch the surface and start
looking at the failure modes.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com