PostgreSQL error 'Could not connect to server: No such file or directory'

Question

Like some others I am getting this error when I run rake db:migrate in my project or even try most database tasks for my Ruby on Rails 3.2 applications.

Answer 1

"Postgres.app" is a better fix if you are on OS X

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Here is the fix:

1. Stop the database
2. cd /var
3. sudo rm -r pgsql_socket
4. sudo ln -s /tmp pgsql_socket
5. chown _postgres:_postgres pgsql_socket
6. Restart PostgreSQL (not your computer)

More information is available at "postgresql 9.0.3. on Lion Dev Preview 1".