Re: physical replication compatibilty

On 4/15/26 3:06 PM, Jatinder Singh Sandhu wrote:
> Dear PostgreSQL Community,
> I am currently planning a major version upgrade from PostgreSQL 16 to
> PostgreSQL 17. I have three node patroni cluster. While I am aware that
> logical replication is the standard approach for cross-version
> migrations, I am curious about the feasibility of physical streaming
> replication in this specific scenario.
> Specifically, I would like to clarify:
>
> 1. Is physical streaming replication backward compatible between these
> two major versions?
> 2. Since many data files remain consistent between versions, is there
> any supported method to leverage physical block-level replication to
> minimize the initial data synchronization time before a cutover?
>
> I understand that WAL formats and system catalogs typically change
> between major releases, but I wanted to confirm if there are any modern
> workarounds or "late-binding" techniques available in the v17 ecosystem.
> Thank you for your time and expertise.

I think you are looking for:

https://www.postgresql.org/docs/17/pgupgrade.html

In particular this:

13. Upgrade streaming replication and log-shipping standby servers

Whether that will play well with the Patroni cluster or not is not
something I can comment on.

It is covered below though:

https://patroni.readthedocs.io/en/latest/existing_data.html#major-upgrade-of-postgresql-version

> Best regards,