Re: pg_upgrade resets timeline to 1

On Thu, May 28, 2015 at 10:18:18AM +0200, Christoph Berg wrote:
> Re: Noah Misch 2015-05-28 <20150528072721.GA4102649@tornado.leadboat.com>
> > > I've just had trouble getting barman to work again after a 9.1->9.4.2
> > > upgrade, and I think part of the problem was that the WAL for this
> > > cluster got reset from timeline 2 to 1, which made barman's incoming
> > > WALs processor drop the files, probably because the new filename
> > > 0001... is now "less" than the 0002... before.
> > 
> > It looks like an upgrade from 9.1.x to 9.3.0 or later has always set the new
> > timeline identifier (TLI) to 1.  My testing confirms this for an upgrade from
> > 9.1.16 to 9.4.1 and for an upgrade from 9.1.16 to 9.4.2, so I failed to
> > reproduce your report.  Would you verify the versions you used?  If you were
> > upgrading from 9.3.x, I _can_ reproduce that.
> 
> Sorry, the "9.1" was a typo, the system was on 9.2.11 before/during
> pg_upgrade.

I ran 9.2.11-to-9.4.1 and 9.2.11-to-9.4.2 upgrades through my script.  Both of
them set TLI=1.  I would be inclined to restore compatibility if this were a
9.4.2 regression, but upgrades from 9.2 to 9.4 have always done that.