> On Oct 12, 2022, at 11:18 AM, Ebin Jozer <ebinjozer(at)gmail(dot)com> wrote:
>
> What would be the rollback step in case the upgrade failed while using pg_upgrade??
- pg_upgrade does pretty extensive pre-flight checks before proceeding
- it does not modify original files, but copies (& modifies the copied catalog files as needed)
(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.)
I've personally never seen a problem once the pre-flight passes and it proceeds.