I am mainly writing this article to remember how to do this next time 😅 (it is 14 or 15 to 16 here, but it should also work with newer versions too). This writeup is for Debian / Ubuntu and is based on this article I found as the first search result on how to upgrade postgres. First, make sure that the packages on your system are up to date and that you have the version of postgres you want to upgrade installed (usually running on port 5433).
apt-get update apt dist-upgrade # Show installed postgres versions apt list --installed | rg postgresql
Apply any configuration changes you made to the running version to the version you want to upgrade. Then you can stop your running postgres version and run
systemctl stop postgresql.service su - postgres # Check if clusters are compatible /usr/lib/postgresql/16/bin/pg_upgrade \ --old-datadir=/var/lib/postgresql/15/main \ --new-datadir=/var/lib/postgresql/16/main \ --old-bindir=/usr/lib/postgresql/15/bin \ --new-bindir=/usr/lib/postgresql/16/bin \ --old-options '-c config_file=/etc/postgresql/15/main/postgresql.conf' \ --new-options '-c config_file=/etc/postgresql/16/main/postgresql.conf' \ --check # Run without --check to upgrade your cluster
Swap the ports of the old and new versions and restart the postgres service.
# change "port = 5434" to "port = 5432" vim /etc/postgresql/16/main/postgresql.conf # change "port = 5432" to "port = 5433" vim /etc/postgresql/15/main/postgresql.conf systemctl start postgresql.service
Make sure you are running the new postgres version.
su - postgres psql -c "SELECT version();"
Remove the old Postgres Version
apt-get remove postgresql-15 postgresql-server-dev-15 rm -rf /etc/postgresql/15/ su - postgres ./delete_old_cluster.sh
Postgres on a Mac with Homebrew
I use Macs running Homebrew for development. And I like to keep my postgres databases in the project repository to make it easy to remove the database by just deleting a directory. And to start the right database along with all the other needed services using a Procfile. Upgrading postgres there works the same way. First install the postgres version you want to upgrade to and create a new data directory.
brew install postgresql@16 /opt/homebrew/Cellar/postgresql@16/16.0/bin/initdb -D databases/postgres_new
Then upgrade the database with
pg_upgrade and remove the old data directory.
/opt/homebrew/Cellar/postgresql@16/16.0/bin/pg_upgrade \ --old-datadir databases/postgres \ --new-datadir databases/postgres_new \ --old-bindir /opt/homebrew/Cellar/postgresql@14/14.9/bin \ --new-bindir /opt/homebrew/Cellar/postgresql@16/16.0/bin \ --check # run pg_upgrade without --check to actually upgrade the database rm -r databases/postgres mv databases/postgres_new databases/postgres