---
title: "Upgrade postgresql-8.4 to postgresql-9.1 on debian"
kind: article
slug: upgrade-postgresql-8-4-to-postgresql-9-1-on-debian
created_at: 2011-11-22
tags:
  - Ubuntu
  - debian
  - dba
  - postgres
  - postgresql
---
Today I upgraded a production PostgreSQL 8.4 database to version 9.1. This was on a Debian server.
~
The first step is to make a full dump of your data. I personally like to store that dump somewhere safe before upgrading. As root:

    su - postgres
    pg_dumpall > dump.sql
    exit
    cp ~postgres/dump.sql /root/

Now you can safely remove the postgresql-8.4 and install postgresql-9.1:

    aptitude purge postgresql-8.4
    aptitude install postgresql-9.1

Next check the postgresql configuration in `/etc/postgresql/9.1/main`. If you make any changes, make sure to restart postgres with `/etc/init.d/postgresql restart`.

Postgresql 9.1 is now up and running, let's import our data back into it.

    su - postgres
    psql < dump.sql

That's all. You're now fully upgraded to PostgreSQL 9.1.