Re: Core team statement on replication in PostgreSQL

On Wed, 2008-06-04 at 10:40 -0400, Tom Lane wrote:
> "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com> writes:
> > Hmm, WAL version compatibility is an interesting question. Most minor
> > releases hasn't changed the WAL format, and it would be nice to allow
> > running different minor versions in the master and slave in those cases.
> > But it's certainly not unheard of to change the WAL format. Perhaps we
> > should introduce a WAL version number, similar to catalog version?
>
> Yeah, perhaps. In the past we've changed the WAL page ID field for
> this; I'm not sure if that's enough or not. It does seem like a good
> idea to have a way to check that the slaves aren't trying to read a
> WAL version they don't understand. Also, it's possible that the WAL
> format doesn't change across a major update, but you still couldn't
> work with say an 8.4 master and an 8.3 slave, so maybe we need the
> catalog version ID in there too.

And something dependent on datetime being integer.

We probably won't need to encode presence of user defined types, like
PostGis , being present ?

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Hannu