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

On Tue, Jul 19, 2011 at 8:45 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:

> Gurjeet Singh wrote:
>
> [ CC to general removed --- emailing only hackers; cross-posting is
> frowned upon. ]
>

I thought these questions were of interest to the general public too.

>
> > .) Is Streaming Replication supported across minor releases, in reverse
> > direction; e.g. 9.0.3 to 9.0.1
> >
> > I think the answer is "it depends", since it would depend upon
> whether
> > any SR related bug has been fixed in the 'greater' of the minor releases.
> >
> > I am assuming that smaller minor release to bigger minor release will
> > always be supported (e.g. 9.0.1 to 9.0.3)
>
> Yes.

I am assuming that's a "yes" to both the directions: older -> newer , and
newer -> older minor releases.

> We could mention in the minor release notes if we break streaming
> replication for a minor release --- or someone will tell us when we do.
>

I am pretty sure the Postgres community would notify its user base via
release notes.

> > .) How reliable is `pg_upgrade -c` (dry run) currently; that is, how
> > accurate is pg_upgrade at predicting any potential problem with the
> eventual
> > in-place upgrade.
> >
> > I'd say it is as reliable as it gets since this is the official tool
> > supported by the project, and it should not contain any known bugs. One
> has
> > to use the latest and greatest 'minor' version of the tool for the major
> > release they are upgrading to, though.
>
> Well, we make no guarantees about the software at all, so it is hard to
> make any guarantee about pg_upgrade either.
>

:) Given the BSD-style license, that's a fair point.

Thanks,
--
Gurjeet Singh
EnterpriseDB Corporation
The Enterprise PostgreSQL Company