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Upgrade PostgreSQL when upgrading Ubuntu
Submitted by Alexis Wilke on Sun, 07/25/2021 - 10:42
The following probably works with other versions of Linux, but I ran those commands on Ubuntu, so if you have a different OS, you may want to verify each step closely first.
The idea when you upgrade to a new OS is that the new version is available in that OS and the old version is now obsolete, so the best is to upgrade to the new database and make sure that the new database work. Then you can get rid of the old cluster.
The following are the steps I used:
sudo su - su - postgresql pg_dropcluster --stop 12 main pg_upgradecluster 10 main
Once the transfer is done AND THE NEW DATABASE WORKS AS EXPECTED, we can then destroy the old cluster by purging the old version:
sudo apt-get purge postgresql-10 postgresql-client-10
WARNING
As noted in the steps, the version I'm upgrading to is 12 from version 10. This is from Ubuntu 18.04 to Ubuntu 20.04. Please make sure to use the correct versions. You can see the versions using the dpkg -l command:
$ dpkg -l | grep postgresql ii postgresql 12+214ubuntu0.1 all object-relational SQL database (supported version) ii postgresql-10 10.17-0ubuntu0.18.04.1 amd64 object-relational SQL database, version 10 server ii postgresql-12 12.7-0ubuntu0.20.04.1 amd64 object-relational SQL database, version 12 server ii postgresql-client-10 10.17-0ubuntu0.18.04.1 amd64 front-end programs for PostgreSQL 10 ii postgresql-client-12 12.7-0ubuntu0.20.04.1 amd64 front-end programs for PostgreSQL 12 ii postgresql-client-common 214ubuntu0.1 all manager for multiple PostgreSQL client versions ii postgresql-common 214ubuntu0.1 all PostgreSQL database-cluster manager
Here we can see that we have version 10 and 12.