Upgrading PostgreSQL from 9.6 to 10.0 on Ubuntu 18.04

How-To guide to upgrade PostgreSQL from 9.6 to 10.0 on Ubuntu after upgrade it to 18.04 version.

images/ubuntu-postgresql.svg

TL;DR

After upgrade to Ubuntu 18.04:

$ sudo pg_dropcluster 10.0 main --stop
$ sudo pg_upgradecluster 9.6 main
$ sudo pg_dropcluster 9.6 main

Upgrade PostgreSQL

During Ubuntu updgrade to 18.04 you receive this message “Configuring postgresql-common”:

Obsolete major version 9.6

The PostgreSQL version 9.6 is obsolete, but the server or client packages are still installed.
Please install the latest packages (postgresql-10 and postgresql-client-10) and upgrade the existing clusters with pg_upgradecluster (see manpage).

Please be aware that the installation of postgresql-10 will automatically create a default cluster 10.0/main.
If you want to upgrade the 9.6/main cluster, you need to remove the already existing 10 cluster (pg_dropcluster —stop 10 main, see manpage for details).

The old server and client packages are no longer supported.
After the existing clusters are upgraded, the postgresql-9.6 and postgresql-client-9.6 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                                 10+190                                      all          object-relational SQL database (supported version)
ii  postgresql-10                              10.3-1                                      amd64        object-relational SQL database, version 10 server
ii  postgresql-10-postgis-2.4                  2.4.3+dfsg-4                                amd64        Geographic objects support for PostgreSQL 10
ii  postgresql-10-postgis-2.4-scripts          2.4.3+dfsg-4                                all          Geographic objects support for PostgreSQL 10 -- SQL scripts
ii  postgresql-9.6                             9.6.8-0ubuntu0.17.10                        amd64        object-relational SQL database, version 9.6 server
ii  postgresql-9.6-postgis-2.3                 2.3.3+dfsg-1                                amd64        Geographic objects support for PostgreSQL 9.6
ii  postgresql-client                          10+190                                      all          front-end programs for PostgreSQL (supported version)
ii  postgresql-client-10                       10.3-1                                      amd64        front-end programs for PostgreSQL 10
ii  postgresql-client-9.6                      9.6.8-0ubuntu0.17.10                        amd64        front-end programs for PostgreSQL 9.6
ii  postgresql-client-common                   190                                         all          manager for multiple PostgreSQL client versions
ii  postgresql-common                          190                                         all          PostgreSQL database-cluster manager
ii  postgresql-contrib                         10+190                                      all          additional facilities for PostgreSQL (supported version)
ii  postgresql-contrib-9.6                     9.6.8-0ubuntu0.17.10                        amd64        additional facilities for PostgreSQL
ii  postgresql-plpython3-9.6                   9.6.8-0ubuntu0.17.10                        amd64        PL/Python 3 procedural language for PostgreSQL 9.6

Run pg_lsclusters, your 9.6 and 10 main clusters should be “online”.

Ver Cluster Port Status Owner    Data directory               Log file
9.6 main    5432 down   postgres /var/lib/postgresql/9.6/main pg_log/postgresql-%Y-%m-%d.log
10  main    5433 down   postgres /var/lib/postgresql/10/main  /var/log/postgresql/postgresql-10-main.log

There already is a cluster “main” for 10 (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 9.6/main when 10/main also exists. The recommended procedure is to remove the 10 cluster with pg_dropcluster and then upgrade with pg_upgradecluster.

Stop the 10 cluster and drop it.

$ sudo pg_dropcluster 10 main --stop

Upgrade the 9.6 cluster to the latest version.

$ sudo pg_upgradecluster 9.6 main

Your 9.6 cluster should now be “down” and you can verifity running pg_lsclusters

Ver Cluster Port Status Owner    Data directory               Log file
9.6 main    5433 down   postgres /var/lib/postgresql/9.6/main ...
10  main    5432 online postgres /var/lib/postgresql/10/main  ...

Check that the upgraded cluster works, then remove the 9.6 cluster.

$ sudo pg_dropcluster 9.6 main

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

$ sudo apt purge postgresql-9.6 postgresql-client-9.6 postgresql-contrib-9.6

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 2018-05-19   3 min read   HowTo   #sql #databases #ubuntu #postgresql #howto