Upgrade PostgreSQL from 9.6 to 10.0 on Ubuntu 16.10

Question

My database is over 600 GB and my current volume is only 1 TB, so that probably limits my options.

My config files are here:

/etc/postgresql/9.6/main         


        

Answer 1

A Step-by-Step Guide

1. Make a backup. Make sure that your database is not being updated.

    pg_dumpall > outputfile
   

2. Install Postgres 10. Follow instructions on this page: https://www.postgresql.org/download/linux/ubuntu/

   Then run sudo apt-get install postgresql-10. A newer version will be installed side-by-side with the earlier version.

3. Run pg_lsclusters:

    Ver Cluster Port Status Owner    Data directory               Log file
    9.6 main    5432 online postgres /var/lib/postgresql/9.6/main /var/log/postgresql/postgresql-9.6-main.log
    10  main    5433 online postgres /var/lib/postgresql/10/main  /var/log/postgresql/postgresql-10-main.log
   

   There already is a cluster main for 10 (since this is created by default on package installation). This is done so that a fresh installation works out of the box without the need to create a cluster first, but of course it clashes when you try to upgrade 9.6/main when 10/main also exists. The recommended procedure is to remove the 10 cluster with pg_dropcluster and then upgrade with pg_upgradecluster.

4. Stop the 10 cluster and drop it:

    sudo pg_dropcluster 10 main --stop
   

5. Stop all processes and services writing to the database. Stop the database:

    sudo systemctl stop postgresql 
   

6. Upgrade the 9.6 cluster:

    sudo pg_upgradecluster -m upgrade 9.6 main
   

7. Start PostgreSQL again

    sudo systemctl start postgresql
   

8. Run pg_lsclusters . Your 9.6 cluster should now be "down", and the 10 cluster should be online at 5432:

    Ver Cluster Port Status Owner    Data directory               Log file
    9.6 main    5433 down   postgres /var/lib/postgresql/9.6/main /var/log/postgresql/postgresql-9.6-main.log
    10  main    5432 online postgres /var/lib/postgresql/10/main  /var/log/postgresql/postgresql-10-main.log
   

9. First, check that everything works fine. After that, remove the 9.6 cluster:

     sudo pg_dropcluster 9.6 main --stop
   

Some notes on pg_upgradecluster

This guide works fine for upgrading from 9.5 to 10.1. When upgrading from an older version, consider omitting -m upgrade on the step #6:

sudo pg_upgradecluster 9.6 main

If you have a really big cluster, you may use pg_upgradecluster with a --link option, so that the upgrade will be in-place. However, this is dangerous — you can lose the cluster in an event of failure. Just don't use this option if not necessary, as -m upgrade is already fast enough.

Based on:

• Docs: Upgrading a PostgreSQL Cluster
• Gist #1: delameko/upgrade-postgres-9.5-to-9.6.md
• Gist #2: johanndt/upgrade-postgres-9.3-to-9.5.md
• What happens if I interrupt or cancel pg_upgradecluster?
• Ubuntu manpage for pg_upgradecluster

Update

This guide works fine for upgrading from 9.6 to 11 and from 10 to 11, as well as from 10 to 13.