Steps to Upgrade PostgreSQL in Ubuntu:

1. Stop cron and other applications that using PostgreSQL.
   
# /etc/init.d/cron stop
# /etc/init.d/apache2 stop
# /etc/init.d/jabberd2 stop
# /etc/init.d/tinyerp-server stop
2. Backup
$ sudo su
# su postgres
$ pg_dumpall > /var/lib/postgresql/all.sql
$ exit
3. Install the latest PostgreSQL version
   
# apt-get install postgresql-8.4..
   Configuring postgresql.conf to use port 5433…Installer will detect the previous version, if exist than the new one will use port 5433.
4. Restore to new version
   
# su postgres
$ /usr/lib/postgresql/8.4/bin/psql template1 -f /var/lib/postgresql/all.sql -p 5433
$ exit
5. Remove the previous version
   
# apt-get remove postgresql-8.3
# apt-get remove postgresql-client-8.3
6. Change port 5433 to 5432 in /etc/postgresql/8.4/main/postgresql.conf:
   
port = 5432Don’t forget to set other configuration, such:
   
listen_addresses = '*'and access rules in /etc/postgresql/8.4/main/pg_hba.conf.
7. Restart your postgreSQL
   
# /etc/init.d/postgresql-8.4 restart
8. Activate cron and other applications, make sure everything is OK.
   
# /etc/init.d/cron start
# /etc/init.d/apache2 start
# /etc/init.d/jabberd2 start
# /etc/init.d/tinyerp-server start