Running on PostgreSQL on Ubuntu

I have discovered that whenever the name MySQL is mentioned, someone will make a choking gurgling noise and complain that it isn’t PostgreSQL. Now that MySQL has been consumed by Sun, which has in turn been consumed iby Oracle, I thought I would see how hard it is to switch.

The main difference between the two seems to be that MySQL started out as an SQL interpreter to which a reliable database backend was eventually attached, whereas PostgreSQL started as a database backend (Postgres) with a SQL interpreter laminated on top. I have a certain sympathy for the idea that you should optimize your database for correctness and reliability before anything else, so maybe that is whether the ‘MySQL—ack! ptht!’ attitude comes from. (For a longer discussion, see MySQL vs PostgreSQL)


The server is installed much as you would expect. On Ubuntu 10.04 LTS, I used:

sudo aptitude install postgresql-8.4

If you are more up-to-date you will have 12.04 and use PostgreSQL 9.1.

The only real gotcha with installing it is the peculiar names given to the supporting packages. For my purposes I need the Python driver and the server. The Python adapter is not called postgresql or anything sensible like that but psycopg2. It is a wrapper around the PostgreSQL library, which naturally is not called libpostgresql, but libpq. The upshot of which is you have to do the following commands:

sudo aptitude install libpq-dev
pip install psycopg2

My moaning about the names aside, this seems to be a pretty good example of a DP-API 2 wrapper, and is Unicode-, Python-3-, and thread-safe.


Since my immediate application, the CAPTION web site, is a Django app, there is actually very little difference to deploying with PostgreSQL, apart from the difficulty I have in typing its name.

For the development version of the site I use SQLite, with a clause in caption/ along the lines of

    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': 'dev.db',

PostgreSQL has a nifty convention whereby if you create a user entry with the same name as a Unix user account, the two are identified—and if there is a same-named database, it is the default for that user. This means, since all my web apps run with unique user names, I do not need to have database passwords embedded in the settings file. These commands set up the database:

sudo -u postgres createuser caption
sudo -u postgres createdb caption

The settings file entry now looks like this:

    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'HOST': '', # Using Unix domain socket
        'NAME': 'caption',

In the case of the CAPTION site, the intitial set of articles was already dumped as the intial data for the database as follows:

./ dumpdata --indent 4 --format yaml articles \
        > articles/fixtures/initial_data.yaml

This meant all I had to get the database populated was run ./ syncdb.

All in all it seems to have gone smoothly—which is as it should be, given that all I am using it for is as an object storagefor Django, the simplest possible case. The resilience of PostgreSQL is likely to be more important for a hypothetical heavily loaded future Kanbo.