Postgresql and django - Unix domain socket

Question

i spend couple of hours to solve these problem but did not reach anything. There are several topics about this problem on the net but none of them says an absolute thing to solve this.

I just installed postgresql in order to use it on my django project.

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql_psycopg2", # Add "postgresql_psycopg2", "postgresql", "mysql", "sqlite3" or "oracle".
        "NAME": "name",                       # Or path to database file if using sqlite3.
        "USER": "postgres",                             # Not used with sqlite3.
        "PASSWORD": "pass",                         # Not used with sqlite3.
        "HOST": "",                             # Set to empty string for localhost. Not used with sqlite3.
        "PORT": "",                             # Set to empty string for default. Not used with sqlite3.
    }
}

this is my settings.py and the error is that

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"?

Did anyone have a solution about it ?

Answer 1

You need to locate a postgres socket. Check main postgres process pid (ps auxw | grep postgres) and list its open unix sockets (lsof -p [PID_OF_POSTGRES_PROCESS] | grep unix). Write this path to HOST option in settings.py.

Installing Postgres from distribution package (apt-get install postgresql) would be much easier (for example empty HOST in settings.py would work) and safer as your distribution will install security updates for you.

Answer 2

Here's another possibility: if you installed a new version of PostgreSQL over an existing version, the installer might have assigned it a non-standard port number.

Django expects PostgreSQL to listen on port 5432. Even if you're using Unix sockets, the socket is named after the port number so this still matters!

Check /etc/postgresql/<version>/main/postgresql.conf for the line port = nnnn. If that number is not 5432, then that's your problem. Another indicator is that your socket file in /var/run/postgresql will be called something like .s.PGSQL.5433, using the non-standard port number.

To fix it, you can either edit the port number in postgresql.conf to use the default (5432), or if you need it to run on a non-standard port number, then set DATABASE_PORT = 'nnnn' in your django settings.py.

Thanks to Erik Forsberg for the pointer!