Daniel,
> Ah, okay, I had missed that discussion, I also did not know it got so
> specific as to address this case (are you sure?) rather than something
> more general, say quorum or N-safe durability.
The way we address that case is through n-safe durability.
> The user may have their own level of durability guarantee they want to
> attain (that's why machine "B" is syncrepped in my example), but when
> doing the switchover I think an override to enable a smooth handoff
> (meaning: everything syncrepped) would be best. What I want to avoid
> is an ack from "COMMIT" from the primary (machine "A"), and then, post
> switchover, the data isn't there on machine A-Prime (or "B", provided
> it was able to follow successfully at all, as in the current case it
> might get ahead of A-prime in the WAL).
Yeah, when I think about your use case, I can understand why it's an
issue. It would be nice to have a superuser setting (or similar) which
could override user preferances and make all transactions synchrep
temporarily. I'm not sure that's going to be reasonable to do for 9.1
though.
-- -- Josh Berkus PostgreSQL Experts Inc.
http://www.pgexperts.com