Re: Upgrading 6 versions between 2 systems

On Mon, Sep 14, 2026 at 4:26 PM Rich Shepard <rshepard(at)appl-ecosys(dot)com>
wrote:

> When I've upgraded postgres in the past on my server/workstation it's
> usually been from one major version to the next. What I want to do now is
> to
> move from 12.7 (on an older OS linux version) to 18.6 (on the current
> version.)
>
> I know that data formats can change with postgres version increases so my
> question is: can I use dumpall in the 12.7 version and move that to the
> host
> running 18.6 since the output is a text .sql file?
>

Yes. Note, though, that a single .sql file is the *slow* way to
export/import a database, especially if it's of any size.

Multithreaded export import is faster. Something like this is what I'd do:

Current system:
cd /path/to/backups
pg_dumpall --globals-only > globals_127.sql
Zlvl="--compress=zstd"
Threads=4 # or whatever
for db in x, y, z; do
pg_dump -p5432 -Fd $Zlvl -v --jobs=$Threads -f $db $db
done

New system:
cd /path/to/backups
psql -af globals_127.sql
Zlvl="--compress=zstd"
Threads=4 # or whatever
for db in x, y, z; do
${pg18}/pg_restore -p5433 -v --jobs=$Threads --clean --create -Fd -d
postgres $db
done

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