If builds of PostgreSQL 9 are failing and you have version 8.x installed, you may need to remove the previous version first. See:
https://github.com/mxcl/homebrew/issues/issue/2510
To build plpython against a specific Python, set PYTHON prior to brewing:
PYTHON=/usr/local/bin/python brew install postgresql
See:
http://www.postgresql.org/docs/9.0/static/install-procedure.html
If this is your first install, create a database with:
initdb /usr/local/var/postgres
If this is your first install, automatically load on login with:
mkdir -p ~/Library/LaunchAgents
cp /usr/local/Cellar/postgresql/9.0.4/org.postgresql.postgres.plist ~/Library/LaunchAgents/
launchctl load -w ~/Library/LaunchAgents/org.postgresql.postgres.plist
If this is an upgrade and you already have the org.postgresql.postgres.plist loaded:
launchctl unload -w ~/Library/LaunchAgents/org.postgresql.postgres.plist
cp /usr/local/Cellar/postgresql/9.0.4/org.postgresql.postgres.plist ~/Library/LaunchAgents/
launchctl load -w ~/Library/LaunchAgents/org.postgresql.postgres.plist
Or start manually with:
pg_ctl -D /usr/local/var/postgres -l /usr/local/var/postgres/server.log start
And stop with:
pg_ctl -D /usr/local/var/postgres stop -s -m fast
Some machines may require provisioning of shared memory:
http://www.postgresql.org/docs/current/static/kernel-resources.html#SYSVIPC
If you want to install the postgres gem, including ARCHFLAGS is recommended:
env ARCHFLAGS="-arch x86_64" gem install pg
To install gems without sudo, see the Homebrew wiki.
==> Summary
/usr/local/Cellar/postgresql/9.0.4: 2577 files, 34M, built in 4.7 minutes