Essentially, if your column is an enum, then indexing it could actually cause MySQL to do more work. Why? Because the data set is so large, the MySQL ends up doing a full scan. So things like keeping track if something is active (1 or 0) then you can expect indexing to hurt.

So how does this effect ActiveRecord? Well, if you’re keeping track of whether a user is active or not you would not want to index that column alone. Nor would you want to index a type column if you were using single table inheritance, again, because there isn’t a lot of variance in the type.

So make sure that you index the right things, like IDs and leave the enum-like columns alone.

Prerequisites

Now I don’t want to go too deep into this, so I’m going to assume that if you are reading this, that you have the following installed

• Mac OS Developer’s Tools
• MacPorts
• Ruby (comes with Leopard)
  • Ruby Gems (also comes with Leopard)

So now that you have all of those dependencies out of the way, let’s get to installing us some PostgreSQL.

PostgreSQL

To install the database software, simply run the following command in Terminal

sudo port install \
  postgresql83 \
  postgresql83-server

This will install the client and server needed for you to run this on your machine. Now pay special attention to the installation script. At the end of installation processes, macports will display a message for you that contains some commands for you to get started with.

Configuration

First, execute these lines of code. This will setup a new database for you to play with

sudo mkdir -p /opt/local/var/db/postgresql83/defaultdb
sudo chown postgres:postgres /opt/local/var/db/postgresql83/defaultdb
sudo su postgres -c '/opt/local/lib/postgresql83/bin/initdb -D /opt/local/var/db/postgresql83/defaultdb'

Start PostgreSQL Automatically

By running the next command, you can have PostgreSQL lunch automatically so that it’s always available to you

sudo launchctl load -w /Library/LaunchDaemons/org.macports.postgresql83-server.plist

pgAdmin III

pgAdmin III is a PostgreSQL management and administrations piece of software. It’s a nice GUI to some things that you may find yourself wanting to do, like created databases and whatnot. Installation of this is pretty cake.

sudo port install pgAdmin3

Upon completion of installation, you can find the application in /Applications/MacPorts/pgAdmin3

PostgreSQL Libraries for Ruby via Gems

I have to admit, the previous installation steps were nothing to cry about; however, it was this step that made me want to put together this little walkthrough.

sudo env ARCHFLAGS="-arch i386" \
  gem install postgres -- \
  --with-pgsql-lib=/opt/local/lib/postgresql83 \
  --with-pgsql-include=/opt/local/include/postgresql83

That’s not exactly your everyday gem install command. For one, the environment variable ARCHFLAGS has to be set. Secondly, the gem command needs to know where the PostgreSQL libraries and include headers are so that it can compile. Looking back, it’s actually quite easy to copy and paste that command, it just took me a while to find out exactly what I needed to make it work.

Fin

Well, I hope that helps anyone looking to install and setup PostgreSQL in Leopard. Until next time…