Upgrade PostgreSQL from 11 to 12 on Ubuntu 20.04

Howto guide for upgrading PostgreSQL from version 11 to 12 on Ubuntu, after its upgrade from version 19.10 to 20.04 (Focal Fossa).

© 2020 Paolo Melchiorre (CC BY-SA) “Sunset behind the Gran Sasso massif seen from my house in Pescara (Italy)”
© 2020 Paolo Melchiorre (CC BY-SA) “Sunset behind the Gran Sasso massif seen from my house in Pescara (Italy)”
Upgrade PostgreSQL on Ubuntu (7 part series)
  1. Upgrade PostgreSQL from 9.5 to 9.6 on Ubuntu 17.04
  2. Upgrade PostgreSQL from 9.6 to 10 on Ubuntu 18.04
  3. Upgrade PostgreSQL from 10 to 11 on Ubuntu 19.04
  4. Upgrade PostgreSQL from 11 to 12 on Ubuntu 20.04
  5. Upgrade PostgreSQL from 12 to 13 on Ubuntu 21.04
  6. Upgrade PostgreSQL from 13 to 14 on Ubuntu 22.04
  7. Upgrade PostgreSQL from 14 to 15 on Ubuntu 23.04

TL;DR

After upgrade Ubuntu from version 19.10 to 20.04:

$ sudo pg_dropcluster 12 main --stop
$ sudo pg_upgradecluster 11 main
$ sudo pg_dropcluster 11 main

Goal

This article is aimed at those like me who use Ubuntu and PostgreSQL to develop locally on their computer and after the last update to Ubuntu 20.04 they have two versions of PostgreSQL installed.

Upgrade PostgreSQL

During Ubuntu updgrade to 20.04 you receive this message “Configuring postgresql-common”:

Obsolete major version 11

The PostgreSQL version 11 is obsolete, but the server or client packages are still installed.

Please install the latest packages (postgresql-12 and postgresql-client-12) and upgrade the existing clusters with pg_upgradecluster (see manpage).

Please be aware that the installation of postgresql-12 will automatically create a default cluster 12/main.

If you want to upgrade the 11/main cluster, you need to remove the already existing 12 cluster (pg_dropcluster --stop 12 main, see manpage for details).

The old server and client packages are no longer supported.

After the existing clusters are upgraded, the postgresql-11 and postgresql-client-11 packages should be removed.

Please see /usr/share/doc/postgresql-common/README.Debian.gz for details.

Use dpkg -l | grep postgresql to check which versions of postgres are installed:

ii postgresql               12+214                all   …
ii postgresql-11            11.7-0ubuntu0.19.10.1 amd64 …
ii postgresql-12            12.2-4                amd64 …
ii postgresql-client        12+214                all   …
ii postgresql-client-11     11.7-0ubuntu0.19.10.1 amd64 …
ii postgresql-client-12     12.2-4                amd64 …
ii postgresql-client-common 214                   all   …
ii postgresql-common        214                   all   …

Run pg_lsclusters, your 11 and 12 main clusters should be “online”.

Ver Cluster Port Status Owner    Data directory              Log file
11  main    5432 online postgres /var/lib/postgresql/11/main …
12  main    5433 online postgres /var/lib/postgresql/12/main …

There already is a cluster “main” for 12 (since this is created by default on package installation). This is done so that a fresh installation works out of the box without the need to create a cluster first, but of course it clashes when you try to upgrade 11/main when 12/main also exists. The recommended procedure is to remove the 12 cluster with pg_dropcluster and then upgrade with pg_upgradecluster.

Stop the 12 cluster and drop it.

$ sudo pg_dropcluster 12 main --stop

Upgrade the 11 cluster to the latest version.

$ sudo pg_upgradecluster 11 main

Your 11 cluster should now be “down” and you can verifity running pg_lsclusters

Ver Cluster Port Status Owner    Data directory              Log file
11  main    5433 down   postgres /var/lib/postgresql/11/main …
12  main    5432 online postgres /var/lib/postgresql/12/main …

Check that the upgraded cluster works, then remove the 11 cluster.

$ sudo pg_dropcluster 11 main

After all your data check you can remove your old packages.

$ sudo apt purge \
postgresql-11 \
postgresql-client-11

Disclaimer

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