Homebrew and PostgreSQL 9.5 (or 9.6)

January 9, 2016

Edit Sept. 30 2016: PostgreSQL 9.6 was released today, and these instructions should work – just replace 9.4 with 9.5 and 9.5 with 9.6. I also have a guide using pg_upgradecluster on Ubuntu.

PostgreSQL 9.5 was released on Jan. 7, with lots of exciting new features.

I wrote a post about upgrading from 9.3 to 9.4 in the past, and many people found it useful, so I decided to update it a bit for the 9.4 to 9.5 upgrade.

1. Turn PostgreSQL off first:

   $ launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
   # or, if you're running a current version of Homebrew
   $ brew services stop postgresql
   

2. Update PostgreSQL itself:

   $ brew update && brew upgrade postgresql
   

3. Make a new, pristine 9.5 database:

   $ initdb /usr/local/var/postgres9.5 -E utf8
   

4. Migrate the data to the new 9.5 database. Note that I have 9.4.5_2 in here, it could be that you aren’t on the latest version. Replace 9.4.5_2 with the most current version of postgres in that directory.

   $ pg_upgrade \
     -d /usr/local/var/postgres \
     -D /usr/local/var/postgres9.5 \
     -b /usr/local/Cellar/postgresql/9.4.5_2/bin/ \
     -B /usr/local/Cellar/postgresql/9.5.0/bin/ \
     -v
   

5. Move 9.5 data directory back to where PostgreSQL expects it to be:

   $ mv /usr/local/var/postgres /usr/local/var/postgres9.4
   $ mv /usr/local/var/postgres9.5 /usr/local/var/postgres
   

6. Start PostgreSQL back up!

   $ launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
   # or, if you're running a current version of Homebrew
   $ brew services start postgresql
   

Note: If you’re using the pg gem for Rails, you should recompile:

$ gem uninstall pg
$ gem install pg

Note 2: If you’ve already uninstalled a previous version of PostgreSQL, there is a good post on StackOverflow with instructions to install previous versions.