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.kla...@aklaver.com



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