Using the pg_upgrade utility for version upgrade

Here in this recipe, we are going to talk about upgrading a PostgreSQL cluster using pg_upgrade. We will cover the upgrading of the PostgreSQL version from 9.5 to 9.6.

Getting ready

The only prerequisite here is that an existing PostgreSQL cluster must be up and running. The required version here is PostgreSQL Version 9.6. These steps are carried out on a 64 bit CentOS machine.

How to do it...

Here are the steps to upgrade a PostgreSQL machine from version 9.5 to version 9.6 using the pg_upgrade utility:

1. Take a full backup of the data directory using a filesystem dump, or use pg_dumpall to back up the data:

           cd  /opt/pgsql/9.5/ 
   
           tar -cvf data.tar data
   

2. The next step would to be install the new version of PostgreSQL 9.6, as mentioned previously.
3. Now that the new version of PostgreSQL is installed, we make the following configuration changes and then initialize the data directory for the new PostgreSQL Version 9.6 database:

      ...