How to: Upgrade PostgreSQL on Ubuntu

Upgrading PostgreSQL is actually quite a straightforward operation compared to doing the same with MySQL or MSSQL.

Here's a quick summary of the process:

1. Back-up the existing PostreSQL data and configuration
2. Install the new version of PostgreSQL
3. Delete the default cluster created by the install
4. Upgrade the existing cluster (which migrates the data and configuration)
5. Delete the old cluster

For this example I upgrade PostgreSQL from version 9.1 to 9.4.  But I assume the steps should carry over without any problems to other versions too.

Please note: This upgrade was performed on a development server so downtime and data loss was not a major concern, therefore this method may not be best for a production environment.

To start, back-up the data and configuration:

Create the file /etc/apt/sources.list.d/pgdg.list:

Edit the new file to add a line for the repository:

The line to add will depend on the version of Ubuntu you are running, the following line is for Ubuntu 12.04 (precise):

Refer to the PostgreSQL documentation for other Ubuntu versions.

Import the repository signing key:

Then run the following to update the package lists and install the latest version:

Then we need to upgrade the existing cluster.

First, stop the PostgreSQL Service:

Delete the default 9.4 cluster created by the 9.4 install (or whatever version has been installed):

Next, we create a new 9.4 cluster from the existing 9.1 cluster (or whatever the existing version is):

Once you're happy everything has been upgraded successfully you can delete the old cluster: