PG::ConnectionBad upgrade to Yosemite and postgresql 9.4.4

Question

I just updated my mac OS X to Yosemite, version 10.10.4, and postgresql to: psql (PostgreSQL) 9.4.4.

After running rake db:migrate on my Rails 4.2.1 application, my terminal session is responding with:

rake aborted!
PG::ConnectionBad: could not connect to server: Connection refused
    Is the server running on host "localhost" (127.0.0.1) and accepting
    TCP/IP connections on port 5432?
could not connect to server: Connection refused
    Is the server running on host "localhost" (::1) and accepting
    TCP/IP connections on port 5432?

Simply entering psql in my terminal session also appears a bit off:

$ psql
psql: could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

After printing out the logs from, cat /usr/local/var/postgres/server.log, I read:

DETAIL:  The data directory was initialized by PostgreSQL version 9.3, which is not compatible with this version 9.4.4.
LOG:  skipping missing configuration file "/usr/local/var/postgres/postgresql.auto.conf"
FATAL:  database files are incompatible with server

I found this answer on SO, but I a hesitant to just start creating a bunch of directories unless that's really what I am suppose to do. I also found an older answer but am not too sure if it's the one to follow.

This SO answer suggests that I remove a, /usr/local/var/postgres/postmaster.pid, but I do not have one, I have a, /usr/local/var/postgres/postmaster.opts -- should I remove the postmaster.opts?

There appears to be lots of advice, but I am not too sure what to follow. Can someone offer some advice in getting my postgresql database running on my rails application?

Answer 1

Basically, I had to drop and recreate my own database and re-seed it with remote staging data. What I did not understand is that the problem with updating a database is that the data itself also needs to be 'updated' in a way. The data was compatible with a different version

Answer 2

You could upgrade the database by following an official guide:

brew switch postgres 9.3    # presuming you already installed 9.4.4
pg_dumpall > outputfile
launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
mv /usr/local/var/postgres /usr/local/var/postgres.old
brew switch postgres 9.4.4
initdb -D /usr/local/var/postgres
psql -d postgres -f outputfile

PostgreSQL upgrade