Bruce Momjian wrote:
> On Sat, Nov 8, 2014 at 05:56:00PM +0100, Andres Freund wrote:
> > On 2014-11-08 11:52:43 -0500, Tom Lane wrote:
> > > Adding a similar level of burden to support a feature with a
> > > narrow use-case seems like a nonstarter from here.
> >
> > I don't understand this statement. In my experience the lack of a
> > usable replication solution that allows temporary tables and major
> > version differences is one of the most, if not *the* most, frequent
> > criticisms of postgres I hear. How is this a narrow use case?
>
> How would replicating DDL handle cases where the master and slave
> servers have different major versions and the DDL is only supported by
> the Postgres version on the master server?
Normally you would replicate between an older master and a newer
replica, so this shouldn't be an issue. I find it unlikely that we
would de-support some syntax that works in an older version: it would
break pg_dump, for one thing.
In other words I view cross-version replication as a mechanism to
upgrade, not something that you would use permanently. Once you
finish upgrading, promote the newer server and ditch the old master.
> If it would fail, does this limit the idea that logical replication
> allows major version-different replication?
Not in my view, at least.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
