I’m a big fan of PostgreSQL and use it on almost every project I do.  There is something about setting up a MySQL instance and managing it that bothers me, so this plugin makes my day.

I have pushed a copy of the plugin to GitHub so that I can keep track of tweaks I make to it as I find compatibility problems.  I am now running WordPress 3.0 and am monitoring my logs for database errors.

Prerequisites

I’m using the Ruby and RubyGems that come installed with Leopard.

You will need to install the following first:

• XCode Developer Tools
• MacPorts

Installing PostgreSQL

Install PostgreSQL from MacPorts using the following command in your Terminal:

sudo port install postgresql84 postgresql84-server

Make sure to follow the instructions printed at the end of the installation, so that you can set up PostgreSQL to start automatically.

Installing pg Gem

Update: The “pg” gem is considered the most current of those that provide a PostgreSQL access layer. I previously mentioned the “postgres” gem.

This is the part that might trip you up if you try the standard gem install pg route. There are two ways to ensure that this works.

The first is to ensure that the directory containing PostgreSQL executables (notably pg_config) is in your PATH. You can add the following to /etc/profile:

export PATH=/opt/local/lib/postgresql84/bin:$PATH

Then run sudo gem install pg as usual.

If you do not modify your PATH, use the following in your Terminal instead so that the PostgreSQL headers and libraries are found:

sudo env ARCHFLAGS="-arch i386"
  gem install pg --
  --with-pgsql-include=/opt/local/include/postgresql84
  --with-pgsql-lib=/opt/local/lib/postgresql84

Update: On Mac OS X 10.6 Snow Leopard, you may need to use “x86_64″ instead of “i386″ in the above command.

I hope that’s the full story…