yay postgresql-old-upgrade

systemctl stop postgresql

# Get last DB version
cat /var/lib/postgres/data/PG_VERSION

# Move current data to olddata
mv /var/lib/postgres/data /var/lib/postgres/olddata
mkdir /var/lib/postgres/data /var/lib/postgres/tmp
chown postgres:postgres /var/lib/postgres/data /var/lib/postgres/tmp

# Initialize a new database as the postgres user and migrate the old data to the new database
su postgres
initdb -D /var/lib/postgres/data --locale=C.UTF-8 --encoding=UTF8 --data-checksums
# Replace PG_VERSION with the old version number from the first step
pg_upgrade -b /opt/pgsql-PG_VERSION/bin -B /usr/bin -d /var/lib/postgres/olddata -D /var/lib/postgres/data

# If you get the error: "old cluster does not use data checksums but the new one does", enter the following command and repeat pg_upgrade
pg_checksums --disable --pgdata /var/lib/postgres/data

exit # Exit your su session

systemctl stop postgresql

su postgres
/usr/bin/vacuumdb --all --analyze-in-stages --missing-stats-only
/usr/bin/vacuumdb --all --analyze-only
exit