Upgrade Postgres 9.3 to 9.4 on OS X

gistfile1.sh

# Shutdown postgres
launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

# Install 9.4
brew update && brew upgrade postgresql

# Make 9.4 DB
initdb /usr/local/var/postgres9.4 -E utf8

# Upgrade postgis or the upgrade will fail (if you require postgis)
# Same goes with other library dependencies
brew upgrade postgis

# http://www.dixis.com/?p=758
# switch jsonc version if you use postgis (you may want to try the upgrade step below first and only do this if you have to)
brew switch json-c 0.11

# Upgrade data
pg_upgrade \
  -d /usr/local/var/postgres \
  -D /usr/local/var/postgres9.4 \
  -b /usr/local/Cellar/postgresql/9.3.4/bin/ \
  -B /usr/local/Cellar/postgresql/9.4.0/bin/ \
  -v
# Make sure the 9.3.x bin dir correlates exactly to the previous version of postgres you were running

# Move data
mv /usr/local/var/postgres /usr/local/var/postgres9.3
mv /usr/local/var/postgres9.4 /usr/local/var/postgres

# Start postgres
launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist