Postgresql adapter (pg): could not connect to server

Question

I get this error every this I run my Rails app (It cannot connect to my local Postgresql)

/Users/leonardo/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.11/lib/ active_record/connection_adapters/postgresql_adapter.rb:1208:in `initialize':  could not connect to server: No such file or directory (PG::Error)    Is the server running locally and accepting connections on Unix domain socket "/var/pgsql_socket/.s.PGSQL.5432"? 

I'm using Postgres.app that it's correctly running.

If I run

$ psql 

I can login properly to Postgresql console.

$ which psql  /Applications/Postgres.app/Contents/MacOS/bin/psql 

Gemfile

source 'https://rubygems.org' ruby "1.9.3"  gem 'rails', '3.2.11' gem "pg" 

database.yml

development:   adapter: postgresql   encoding: unicode   username: leonardo   password:    database: zapping   port: 5432   

Postgresql (Console)

$ psql leonardo=# \l 

Answer 1

Try adding host: localhost to your database.yml. (Based on: https://stackoverflow.com/a/10793186/919641)

Answer 2

Your Pg gem was compiled against the PostgreSQL libpq pre-installed in Mac OS X and you're using the psql that you installed in a newer version, or vice versa.

This can be worked around by specifying a TCP/IP connection, by adding localhost to database.yml, but it's better to compile the Pg gem against the libpq for the server you're actually running. To do that, you should be able to set the PATH environment variable to the folder with the correct pg_config in it before compiling. In your case that'll be somewhere within Postgres.app.