Re: Postgresql community edition upgrade

On 12 October 2022 18:29:12 Scott Ribe <scott_ribe(at)elevated-dev(dot)com> wrote:
> (I think even if you use link mode, it doesn't modify original catalog
> files, so you can start the old one until you have started the new one. I'd
> look for more info from someone more knowledgeable about this exact process.)

Correct. I've had it go wrong with link mode. As long as you don't start
the new cluster, the old one still works absolutely fine with a minor
(documented) step.

IIRC, the data files (in /data/base) are linked (and unchanged by the
process). The control files, transaction logs, etc aren't, but the old
control files are "disabled" to prevent accidental starting of the old
cluster (it's easy to re-enable it)

See (17) of the Usage notes

https://www.postgresql.org/docs/current/pgupgrade.html

Paul

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