These are instructions for setting up 64-bit postgres on Mac OS X 10.6, Snow Leopard using MacPorts. My purpose was to be able to run Rails' tests when creating patches for ActiveRecord.

This is a pure Snow Leopard install (not upgraded from 10.5 Leopard). There may be some complications if you upgraded. Good luck. ;)

Install with macports:

sudo port install postgresql84 postgresql84-server

While that's happening, update PATH in the appropriate file

(mine is ~/.bash_login, yours may be ~/.profile, ~/.bash_profile, or something else)

(in the correct file)
export PATH="/opt/local/lib/postgresql84/bin:$PATH"

Follow the instructions that 'port install' printed out:

"To create a database instance, after install do"

sudo mkdir -p /opt/local/var/db/postgresql84/defaultdb  
sudo chown postgres:postgres /opt/local/var/db/postgresql84/defaultdb  
sudo su postgres -c '/opt/local/lib/postgresql84/bin/initdb -D  /opt/local/var/db/postgresql84/defaultdb'

"Execute the following command to start it, and to cause it to launch at startup:"

sudo port load postgresql84-server

Create a postgres superuser for your username:

sudo -u postgres createuser your-username-here
Shall the new role be a superuser? (y/n) y

Install the ruby gem:

sudo gem install pg

Set up the rails activerecord test db:

cd your-rails-checkout-dir/activerecord
rake postgresql:build_databases

Verify test passage:

rake test_postgresql

It works! Hopefully. :)

Some possibly helpful references

• general flow
• know which postgres gem to use
• possibly relevant 64-bit info
• create a pg superuser for your username