Re: Guidance Needed for PostgreSQL Upgrade from 12 to 15 - Mailing list pgsql-admin

Dear Team,

Thank you for your valuable inputs on the PostgreSQL upgrade.

Given the challenges encountered with pg_upgrade in a Kubernetes environment, we're considering a more traditional approach involving pg_dumpall to take backup and then restore the data using psql utility.

Can you please advise if this approach will be fine or you see any issues with it?

A high level overview of the steps:

1. Backup:

   * Connect to the existing PostgreSQL 12 pod.

   * Execute pg_dumpall to create a complete database dump.

 2. New Deployment:

   * Create a new PostgreSQL 16 pod.

   I think no need to use initidb as it will be autoinitialized .

 3. Restore:

   * Transfer the backup file to the new pod.

   * Use psql utility to restore the database from the dump.

 4. Verification:

   * Thoroughly test the restored database to ensure data integrity and functionality.

 5. Cutover:

   * Once verification is complete, switch over traffic to the new PostgreSQL 16 pod.

   * Delete the old PostgreSQL 12 pod.

Best Regards,

Ramzy

On Wed, Nov 20, 2024, 02:47 Scott Ribe <scott_ribe@elevated-dev.com> wrote:

> On Nov 19, 2024, at 1:40 PM, Kris Deugau <kdeugau@vianet.ca> wrote:
>
> I stand corrected.  I hadn't read the docs on pg_upgrade for quite a while, but after reading the last section in https://www.postgresql.org/docs/current/pgupgrade.html:
>
> "If you did not start the new cluster, the old cluster was unmodified except that, when linking started, a .old suffix was appended to $PGDATA/global/pg_control. To reuse the old cluster, remove the .old suffix from $PGDATA/global/pg_control; you can then restart the old cluster."
>
> I see what you mean.
>

There's nothing wrong per se about taking the snapshot before, I was just saving the potential time of re-running pg_upgrade. Heck, take a snapshot before *and* after ;-)