Postgres could not connect to server because rails was connecting to it on the wrong port

So this tripped me up today and initial googling was not very helpful, maybe because I did not zero in on the right part of the error soon enough, but I hope you find this helpful.

I created a new Rails app and set up a Postgres database on my development machine. Then as soon as I tried to run rake db:create, I got the following error

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?

I ended up going down a different route, trying to figure out if the server is running, googling and renaming a pid file, etc…..

When I finally zeroed in on the port number at the end, I learned that I can check what port Postgres is listening on with sudo -u postgres psql -c "SHOW port;"

This showed me that postgres was running on 5433 while Rails was trying to connect to 5432. All I had to do was add a line in my database.yml to specify the port.

default: &default
  adapter: postgresql
  encoding: unicode
  host: localhost
  port: 5433
  username: postgres
  password: postgres
  pool: 5

Full disclosure, my username and password is something else, but if you are setting up Postgres in development for the first time, you can get away with these.

Problem solved!