I recently setup my development system from scratch and one of the tasks is installing PostgreSQL as my apps are almost always deployed to Heroku and they <3 PG.
As you may or may not know, Lion ships with a castrated Postgres installation which (if you don’t already know this (!!!!)) can make it challenging to use something like Homebrew for your installation medium.
To avoid this whole situation I suggest you checkout Postgres.app. It’s written by the guys @ Heroku and is essentially a .app that you drop in your Applications folder. Run whenever you want a PG server — it’s THAT easy.
After installing it I had some issues but was able to figure it out so that’s really the “gotcha” part of this post.
On first launch i realized i couldn’t connect to the PG server and immediately went to my system’s console for clues. This was sitting there looking pretty:
Ye olde “Failed system call was shmget” error….
In a nut shell there are two ways to fix this:
1- Temporary Solution: Gone after reboot.
2- Permanent Solution: Forever, forever, ever, forever, ever? Yep. After reboot the settings will stick.
You can also see this post for further details.