Re: PostgreSQL Downgrades

On 04/05/2013 03:33 PM, Pete Wall wrote:
> Is it possible to downgrade PostgreSQL by a major version?
>
> If I want to upgrade a PG database from 8.x to 9.x, I have to dump the
> db, install the new binaries and import the dump file.  This works
> fine going forward, but what if I need to rollback my changes?  I
> cannot dump the 9.x database and import it with 8.x binaries, because
> the 9.x dump contains keywords that the old binaries don't understand
> (e.g. REPLICATION).
>
> I could import the original 8.x dump file again, but then I've lost
> any changes made when using the new binaries.
>
> Is there a supported way to downgrade PostgreSQL by major versions?
>
Is it *possible*? Yes. Assuming that you haven't made use of any
features that are unavailable in the old version or made any changes to
accommodate differences in the new version.

Is there a *supported* way. No. You will need to do roll-your-own. It's
possible that you could do a data-only dump on the new database and get
away with only minor tweaks required to restore the data into an
existing empty prior-version database. The feasibility depends on the
nature of your data and the amount of work you are willing to do.

It might help to understand the use-case underlying your interested in
progressing backward.

Cheers,
Steve