Message-ID: <71e9dfb092c0b78a4e6860c7fadfd9d47f55fa32.camel@cybertec.at>
Subject: Re: Postgres 12 update to new major version
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Boris =?UTF-8?Q?Dov=C4=8D=C3=ADk?= <bdovcik@gmail.com>,
	pgsql-general@lists.postgresql.org
Date: Fri, 05 Jun 2026 23:59:20 +0200
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On Fri, 2026-06-05 at 14:11 +0200, Boris Dov=C4=8D=C3=ADk wrote:
> I have a question regarding the update of the production database (multip=
le TB of data)
> from version 12 to higher major version. We would like to jump to 15 or 1=
6. DB is installed
> on a Linux server with one replica on another, it is not on cloud.
>=20
> First question is should we perform=C2=A0updates one by one? 12 -> 13 -> =
14 etc. or is it
> viable=C2=A0to jump to 16 right away? (We have few functions but usually =
its plain tables)

You can jump over versions, but you should not upgrade to an old release li=
ke v15 or
v16.  Go to v18 or better.  It looks like you are not too eager to upgrade =
frequently,
otherwise you would not be on v12 today.  So I recommend that you put the t=
ime when
the next upgrade will be necessary as far into the future as possible.

> Second we are contemplating=C2=A0options for the update since we are limi=
ted with downtime.
> We could get 4 hours of downtime for the whole update (either via pg_upda=
te or dumps).
> We are not sure how to estimate the time for direct update or dumps. What=
 would be the
> recommended way for it?

You should use pg_upgrade --link.  Then the upgrade can be a matter of minu=
tes, unless
you have lots and lots of tables, functions or large objects.

Yours,
Laurenz Albe