Re: Guidance Needed for PostgreSQL Upgrade from 12 to 15

Hi Ron,

Thanks for your response l.
Logical replication i can't use because of primary key issues.
I have multiple DBs, then multiple schemas and then multiple tables,
functions etc
Will I be able to copy whole cluster including data, roles, globals
everything using pg_dump?
Also while restoring, can I restore everything, the same structure, in a
single go using pg_restore?

On Fri, Nov 22, 2024, 00:16 Ron Johnson <ronljohnsonjr(at)gmail(dot)com> wrote:

> pg_dumpall uses a single thread to generate one big .sql file. If your
> database(s) are small enough that generating (even a compressed) .sql file,
> copying it then importing it is Good Enough, then that's fine.
>
> Otherwise, "logical replication" or "multithreaded pg_dump" is what you
> want.
>
> On Thu, Nov 21, 2024 at 1:17 PM Motog Plus <mplus7535(at)gmail(dot)com> wrote:
>
>> 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(at)elevated-dev(dot)com>
>> wrote:
>>
>>> > On Nov 19, 2024, at 1:40 PM, Kris Deugau <kdeugau(at)vianet(dot)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 ;-)
>>>
>>>
>>>
>>>
>
> --
> Death to <Redacted>, and butter sauce.
> Don't boil me, I'm still alive.
> <Redacted> lobster!
>