Re: We have a requirement to downgrade from PostgreSQL 9.5.4 to 9.5.2

On Tue, Sep 20, 2016 at 3:21 PM, KGA Official <kga(dot)official(at)gmail(dot)com> wrote:
> Regarding "are you really going to downgrade again"?
> The upgraded postgres will be bundled along with product code changes and
> other products. So, if someone finds product issues, they will roll back
> everything together.
> So, essentially, yes. One requirement of the roll out is that it be possible
> to roll-back.

Roll-out can be a complicated requirement knowing that sometimes minor
releases can introduce new GUC parameters and those can generate WAL
records. Though it is a rare fact, it is not impossible, and things
are kept compatible as much as possible. Personally I find deploying a
backup of PGDATA instead of reusing an existing PGDATA with older
binaries after it has run with newer binaries a more iron-solid
approach, and I've learnt to be careful with such things..
--
Michael