Upgrading PostgreSQL from 17 to 18

1. Install new versions
   Install PostgreSQL itself:

sudo apt update
sudo apt install postgresql-18

Check if installation was successful:

ls /usr/lib/postgresql/
ls -la /var/lib/postgresql/

Install extensions:

sudo apt install postgresql-18-pgvector

curl -L "https://github.com/paradedb/paradedb/releases/download/v0.21.8/postgresql-18-pg-search_0.21.8-1PARADEDB-noble_amd64.deb" -o /tmp/pg_search.deb
sudo apt-get install -y /tmp/*.deb
rm /tmp/pg_search.deb

sudo apt install postgresql-18-postgis-3

2. Migrate data

Check existing clusters

pg_lsclusters

Migrate

sudo pg_dropcluster 18 main --stop
screen -S pg_upgrade
sudo pg_upgradecluster 17 main

Press Ctrl + a then d to detach screen. To re-attach:

screen -r pg_upgrade

Ctrl + d to close screen

Check again

pg_lsclusters

Usually you're done at this point, all the steps below are optional to verify installation is complete and clean up leftovers.

a. Check that configs migrated cleanly

sudo diff -u /etc/postgresql/17/main/postgresql.conf \
             /etc/postgresql/18/main/postgresql.conf

sudo diff -u /etc/postgresql/17/main/pg_hba.conf \
             /etc/postgresql/18/main/pg_hba.conf

b. Copy old configs if needed

sudo cp /etc/postgresql/17/main/pg_hba.conf \
        /etc/postgresql/18/main/pg_hba.conf

sudo cp /etc/postgresql/17/main/pg_ident.conf \
        /etc/postgresql/18/main/pg_ident.conf

c. Upgrade extensions in place if needed

sudo -u postgres psql
SELECT version();
\dx
ALTER EXTENSION pgvector UPDATE;
ALTER EXTENSION pg_search UPDATE;
ALTER EXTENSION postgis UPDATE;

3. Update your cert paths if needed

nano ./psql_rotate_certs.sh
nano /etc/postgresql/18/main/postgresql.conf
./psql_rotate_certs.sh

4. Drop old cluster

sudo apt remove postgresql-17
sudo apt autoremove

5. Restart and validate

sudo systemctl restart postgresql
sudo -u postgres psql -c "SHOW shared_buffers;"
apt-get update && apt-get full-upgrade -y && apt-get autoremove -y && apt-get clean
reboot now

Done!