Re: PostgreSQL Upgrade (v9.5 to v12) with Django 2.0

>> if we use the --link option for pg_upgrade, what would be the
rollback plan in case issues arise during or after the upgrade?

restoring a backup would be your option in such a case I guess.

On 15.06.25 12:05, Kushal Shri wrote:
>
> Currently, our plan is to test pg_upgrade using the --link option to
> upgrade from PostgreSQL 9.5 to 12, then upgrade Django to the latest
> supported version, and finally perform another pg_upgrade to
> PostgreSQL 16.
>
> Since Django 2.0 is officially tested and supported only up to
> PostgreSQL 10, would you recommend upgrading to PostgreSQL 10 using
> pg_upgrade as the first phase, followed by logical replication to
> PostgreSQL 16 as the final target after upgrading Django as well?
>
> and, if we use the --link option for pg_upgrade, what would be the
> rollback plan in case issues arise during or after the upgrade?
>
>
> On Sat, 14 Jun 2025 at 01:59, Eduardo Barbachan
> <eduardobarbachandb(at)gmail(dot)com> wrote:
>
> I'm sorry if this part of the answer should not be given in this
> context, but I happen to be in this list (as a lurker for most of
> the time) and be a Django user.
> Till Django 4.2 (LTS) postgres 12 is supported. Django 5.2 (LTS
> also) supports postgres 17+.
>
>
> Em qui., 12 de jun. de 2025 às 10:19, Laurenz Albe
> <laurenz(dot)albe(at)cybertec(dot)at> escreveu:
>
> On Wed, 2025-06-11 at 16:39 +0545, Kushal Shri wrote:
> > We are in the process of planning a PostgreSQL upgrade and
> would greatly
> > appreciate any insights, best practices, or lessons learned
> from your experiences.
> >
> > Current Setup:
> >    - PostgreSQL version: 9.5
> >    - Django version: 2.0
> >    - Database size: ~3 TB
> >    - One Master 4 Replicas(Streaming Replication)
> >
> > We are taking a phased approach to this upgrade. In Phase 1,
> our goal is to
> > upgrade PostgreSQL from v9.5 to v12, ensuring compatibility
> with our current
> > Django 2.0 application.
>
> That's already wrong.  PostgreSQL v12 is out of support.
> Upgrade to v17 or v18.
>
> > As part of this, I would like to understand:
> >
> > - What is the highest PostgreSQL version reliably supported
> with Django 2.0?
>
> You'll have to ask Django what they support.
>
> > - What upgrade strategies or methods have worked well for
> you in similar environments?
>
> pg_upgrade --link
>
> > - Any gotchas or performance considerations to keep in mind
> with large databases
> >   during such upgrades?
>
> Make sure you don't have millions of Large Objects, otherwise
> the upgrade
> will be very slow and memory consuming.
>
> Yours,
> Laurenz Albe
>
>
>
>
> --
>
> Att.
>
> Eduardo  Barbachan
>