Re: Upgrade from postgresql-9.5alpha1 to postgresql-9.5alpha2 (Debian packages)

On 2015-08-18 20:40:10 +0900, Masahiko Sawada wrote:
> On Tue, Aug 18, 2015 at 6:06 PM, Peter J. Holzer <hjp-pgsql(at)hjp(dot)at> wrote:
> > It looks like the catalog version has changed between 9.5alpha1 and
> > 9.5alpha2:
[...]
> > So, what's the best way to do the upgrade?
> >
> > * Copy the bindir before the upgrade (or restore from backup) to a safe
> > place and do pg_upgrade?
> > * Initdb a new cluster and restore yesterdays backup?
> > * Something else?
> >
>
> I've not used pg_upgrade at such case, but If you have a enough time
> to do upgrading, I will suggest to take backup(pg_dumpall) from
> current cluster and then restore it to new cluster.

Of course you would have to make a backup before the upgrade to restore
it afterwards. I could of course have forcibly downgraded to alpha1
again and made a new backup, but since this is a test system I just
decided to drop and recreate the cluster and restore yesterday's backup.
(One of my colleagues won't be too pleased about that, I think)

> I think pg_upgrade is basically used at major version upgrading.

This was basically a major version upgrade, the problem was that it
wasn't reflected in the package/directory structure (normally the
postgres debian packages are quite fastidious in separating everything
so that you have both an old and a new installation in the places where
pg_upgradecluster expects them), and that I didn't expect it (the
possibility of catalog version changes from one alpha release to the
next was discussed before the release of alpha1, but I somehow
classified that as "theoretically possible but not likely" - my fault),
and finally that I don't really understand the finer points of
pg_upgrade (I managed to use it in a similar situation some time ago,
but I had to read the source code of pg_upgradecluster (and I think I
even single-stepped through it in the debugger) to figure out the
parameters and unfortunately I didn't take notes).

No big harm done (alpha software on a test system - I expect things to
blow up once in a while), but maybe the person preparing the alpha
releases can figure out how to make the upgrade smoother. At least a
warning in the release announcement would be nice (wouldn't have helped
me as I have to admit that I read that only after I upgraded, but it
would help those who do things in the right order ;-) ).

hp

--
_ | Peter J. Holzer | I want to forget all about both belts and
|_|_) | | suspenders; instead, I want to buy pants
| | | hjp(at)hjp(dot)at | that actually fit.
__/ | http://www.hjp.at/ | -- http://noncombatant.org/