Re: pg_upgrade: can I use same binary for old & new?

On 7/5/25 12:19, Pierre Fortin wrote:
> On Sat, 05 Jul 2025 14:30:20 -0400 Tom Lane wrote:
>

>> I'd say give it a try; be sure to use one of the pg_dump modes
>> that compress the data.
>
> OK... I failed to mention I have several databases in this cluster; so
> digging into pg_dumpall, I see:
> --binary-upgrade
> This option is for use by in-place upgrade utilities. Its use for
> other purposes is not recommended or supported. The behavior of the
> option may change in future releases without notice.
>
> pg_upgrade has --link option; but I'm puzzled by this option in a
> dumpall/restore process. My imagination wonders if this alludes to a way
> to do something like:
> pg_dumpall --globals-only --roles-only --schema-only ...
> Would restoring this be a way to update only the control structures? Big
> assumption that the actual data remains untouched...
>
> Inquiring mind... :)
>
> Back to my upgrade issue...
> All my DBs are static (only queries once loaded). Assuming the dumpall
> file fits on one of my drives:
> pg_dumpall -f <path>/PG.backup -v

If you really want to use pg_dumpall and get compression then something
like:

pg_dumpall -U postgres | gzip > pg_backup.gz

Though this will take some time and really is probably better handled using:

pg_dumpall -U postgres -g > pg_globals.sql

and then:

pg_dump -d <some_db> -U -Fc -f <some_db>.out

for each database. This will use compression by default.

Neither of these options will be as quick as doing pg_upgrade with
--link. Though at this point you are boxed in by not being able to run
multiple Postgres versions on one machine.

> appears to be all I need? pg_dump has compression by default; but I don't
> see compression with dumpall other than for TOAST.
>
> Thanks, You guys are awesome!
>
>> regards, tom lane
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com