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Date: Mon, 2 Mar 2026 19:16:35 +0100
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Subject: Re: upgrade from 13 to 16
To: pgsql-admin@lists.postgresql.org
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From: Holger Jakobs <holger@jakobs.com>
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Am 02.03.26 um 15:31 schrieb Ron Johnson:
> On Mon, Mar 2, 2026 at 9:09 AM listy <listy@localities.work> wrote:
>
>     Cannot say about Debian but RHEL family (perhaps exceptions exist)
>     do not, certainly not on Centos, Ubuntu which I use, yes.
>     But also rhel/centos do not do major PGsql rel. upgrade within the
>     same/one OS release, I do not think so.
>     What happened to me - what I did rather - was upgrade from c9 to
>     c10. (not officially supported.)
>
>
> This is why I strongly urge you to use the PGDG repositories, not the 
> packages which RHEL builds.
>
> -- 
> Death to <Redacted>, and butter sauce.
> Don't boil me, I'm still alive.
> <Redacted> lobster!

Yes, RHEL doesn't take into account that PostgreSQL will ever be 
upgraded to another major version. They support the version which was 
current when they had their feature freeze for the lifetime of the system.

Therefore Ron is perfectly correct in writing that everybody should use 
the PGDG from the beginning.

You might have success installing the new version from PGDG repos and 
then run pg_upgrade (with all 4 mentioned options) from the new version. 
The preconditions for pg_upgrade are:

  * you have the old and the new software version installed (pg-13 and
    pg-18) in different directories
  * you have the old cluster unchanged and an empty new cluster in
    different directories

Maybe it helps to move the data directory of the old cluster before 
installing the new software package. Make sure you also change the path 
in the systemd service unit of the old version.

If the database isn't large, dump & restore will also work fine.

Regards,

Holger

-- 

Holger Jakobs, Bergisch Gladbach, Germany

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    <div class="moz-cite-prefix">Am 02.03.26 um 15:31 schrieb Ron
      Johnson:<br>
    </div>
    <blockquote type="cite"
cite="mid:CANzqJaBMxjN3eFR0hb2SmM-XzQ86jQwjvdi0eKzCb0FUx2zBQQ@mail.gmail.com">
      <meta http-equiv="content-type" content="text/html; charset=UTF-8">
      <div dir="ltr">
        <div dir="ltr">On Mon, Mar 2, 2026 at 9:09 AM listy &lt;<a
            href="mailto:listy@localities.work" moz-do-not-send="true"
            class="moz-txt-link-freetext">listy@localities.work</a>&gt;
          wrote:</div>
        <div class="gmail_quote gmail_quote_container">
          <blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
            <div> <font size="2" face="Courier 10 Pitch">Cannot say
                about Debian but RHEL family (perhaps exceptions exist)
                do not, certainly not on Centos, Ubuntu which I use,
                yes.<br>
                But also rhel/centos do not do major PGsql rel. upgrade
                within the same/one OS release, I do not think so.<br>
                What happened to me - what I did rather - was upgrade
                from c9 to c10. (not officially supported.)</font> </div>
          </blockquote>
        </div>
        <div><br clear="all">
        </div>
        <div>This is why I strongly urge you to use the PGDG
          repositories, not the packages which RHEL builds.</div>
        <div><br>
        </div>
        <span class="gmail_signature_prefix">-- </span><br>
        <div dir="ltr" class="gmail_signature">
          <div dir="ltr">Death to &lt;Redacted&gt;, and butter sauce.
            <div>Don't boil me, I'm still alive.<br>
              <div>
                <div>&lt;Redacted&gt; lobster!</div>
              </div>
            </div>
          </div>
        </div>
      </div>
    </blockquote>
    <p>Yes, RHEL doesn't take into account that PostgreSQL will ever be
      upgraded to another major version. They support the version which
      was current when they had their feature freeze for the lifetime of
      the system.</p>
    <p>Therefore Ron is perfectly correct in writing that everybody
      should use the PGDG from the beginning.</p>
    <p>You might have success installing the new version from PGDG repos
      and then run pg_upgrade (with all 4 mentioned options) from the
      new version. The preconditions for pg_upgrade are:</p>
    <ul>
      <li>you have the old and the new software version installed (pg-13
        and pg-18) in different directories</li>
      <li>you have the old cluster unchanged and an empty new cluster in
        different directories</li>
    </ul>
    <p>Maybe it helps to move the data directory of the old cluster
      before installing the new software package. Make sure you also
      change the path in the systemd service unit of the old version.</p>
    <p>If the database isn't large, dump &amp; restore will also work
      fine.</p>
    <p>Regards,</p>
    <p>Holger</p>
    <div class="moz-signature">-- <br>
      <p>Holger Jakobs, Bergisch Gladbach, Germany</p>
    </div>
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