Re: A few user-level questions on Streaming Replication and pg_upgrade

Robert Haas wrote:
> On Wed, Jul 20, 2011 at 3:29 PM, Bruce Momjian <bruce@momjian.us> wrote:
> > Robert Haas wrote:
> >> On Wed, Jul 20, 2011 at 2:53 PM, Bruce Momjian <bruce@momjian.us> wrote:
> >> >> I am assuming that's a "yes" to both the directions: older -> newer , and
> >> >> newer -> older minor releases.
> >> >
> >> > Yes, I believe both directions would work unless we mentioned it the
> >> > release notes, in which cases it might not work, or might work older to
> >> > newer but newer to older.
> >>
> >> I don't see how this would get broken in a minor release. ?We'd have
> >> to change the WAL format or the tuple format, which is definitely not
> >> minor release material.
> >
> > If there was a bug in the xlog stream content we might not be able to
> > fix it without breaking compatibility. ?Rare, but possible.
> 
> OK, fair enough.  But I think the likelihood is extremely low.

It would require a case where we couldn't distinguish a valid from an
invalid WAL entry, or the streaming used by the old server was
sufficiently broken that we didn't want to support it.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +