Re: postgres 9.6.2 update breakage

[Christopher Allan Webber]

Hi there!

Jan Nieuwenhuizen writes:

> Hi!
>
> I reconfigured my system and pulled in the postgres 9.6.2 update.  Now
> postgres does not start, /var/log/messages has
>
>     May 12 13:02:52 localhost postgres[451]: [1-1] FATAL:  database files are 
> incompatible with server
>     May 12 13:02:52 localhost postgres[451]: [1-2] DETAIL:  The data 
> directory was initialized by PostgreSQL version 9.5, which is not compatible 
> with this version 9.6.2.
>
>
> I have reverted the postgres update and everything is "fine" again.s
>
> How do we want to handle this?  I imagine that postgres has some way to
> update its database...and I probably can figure out how to do that.  But
> do our users need to know this?  And more importantly, if I upgrade,
> will I be able to revert to a previous generation of my system?

Yes, so therew as some conversation on this last year:

  https://lists.gnu.org/archive/html/guix-devel/2016-06/msg00917.html

Basically, we should have a package like "postgresql-upgrade".  It
should use:

  https://www.postgresql.org/docs/9.4/static/pgupgrade.html

... and do an upgrade between postgres versions.

Any volunteers want to work on this? :)