Postgresql – postgres create database; column ‘dataconfig’ does not exist

Postgres 9.5 (released since 2016-01-07) offers an "upsert" command, also known as an ON CONFLICT clause to INSERT:

INSERT ... ON CONFLICT DO NOTHING/UPDATE

It solves many of the subtle problems you can run into when using concurrent operation, which some other answers propose.

This really looks like a file permissions error. Unix domain sockets are files and have user permissions just like any other. It looks as though the OSX user attempting to access the database does not have file permissions to access the socket file. To confirm this I've done some tests on Ubuntu and psql to try to generate the same error (included below).

You need to check the permissions on the socket file and its directories /var and /var/pgsql_socket. Your Rails app (OSX user) must have execute (x) permissions on these directories (preferably grant everyone permissions) and the socket should have full permissions (wrx). You can use ls -lAd <file> to check these, and if any of them are a symlink you need to check the file or dir the link points to.

You can change the permissions on the dir for youself, but the socket is configured by postgres in postgresql.conf. This can be found in the same directory as pg_hba.conf (You'll have to figure out which one). Once you've set the permissions you will need to restart postgresql.

# postgresql.conf should contain...
unix_socket_directory = '/var/run/postgresql'       # dont worry if yours is different
#unix_socket_group = ''                             # default is fine here
#unix_socket_permissions = 0777                     # check this one and uncomment if necessary.

EDIT:

I've done a quick search on google which you may wish to look into to see if it is relavent. This might well result in any attempt to find your config file failing.

http://www.postgresqlformac.com/server/howto_edit_postgresql_confi.html

Error messages:

User not found in pg_hba.conf

psql: FATAL:  no pg_hba.conf entry for host "[local]", user "couling", database "main", SSL off

User failed password auth:

psql: FATAL:  password authentication failed for user "couling"

Missing unix socket file:

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

Unix socket exists, but server not listening to it.

psql: could not connect to server: Connection refused
    Is the server running locally and accepting
    connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?

Bad file permissions on unix socket file:

psql: could not connect to server: Permission denied
    Is the server running locally and accepting
    connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?