Re: [PoC] pg_upgrade: allow to upgrade publisher node

On Fri, Sep 22, 2023 at 9:40 AM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Thu, Sep 21, 2023 at 01:50:28PM +0530, Amit Kapila wrote:
> > We have discussed this point. Normally, we don't have such options in
> > upgrade, so we were hesitent to add a new one for this but there is a
> > discussion to add an --exclude-logical-slots option. We are planning
> > to add that as a separate patch after getting some more consensus on
> > it. Right now, the idea is to get the main patch ready.
>
> Okay.  I am wondering if the subscriber part is OK now without an
> option, but that could also be considered separately, as well.  At
> least I hope so.

+1 for an option to skip upgrade logical replication slots for the
following reasons:
- one may not want the logical replication slots on the upgraded
instance immediately - unless the upgraded instance is tested and
determined to be performant.
- one may not want the logical replication slots on the upgraded
instance immediately - no logical replication setup is wanted on the
new instance perhaps because of an architectural/organizational
decision.
- one may take backup of the postgres instance with logical
replication slots using any of the file system/snapshot based backup
mechanisms (not pg_basebackup), essentially getting the on-disk
replication slots data as well; the pg_upgrade may fail on the
backed-up instance.

I agree to have it as a 0002 patch once the design and things are
finalized for the main patch.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com