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Asked: 2026-06-18T08:04:07+00:00

Apparently this is a pretty hard question to ask because, simple as it is,

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Apparently this is a pretty hard question to ask because, simple as it is, no one seems to have answered it.

I have PostgreSQL running on ubuntu 12.10 server (no GUI).

My goal – my question – is to create a database named “mydb” and a user “admin” such that I can give this command as an ordinary user from the shell and connect to the database:

$ psql -U admin -d mydb

But I cannot find the answer to this anywhere.

I can log in as user postgres by su’ing and running the psql command:

$ sudo su -m postgres
postgres@baseubu1210dev:~$ psql
psql (9.1.7)
Type "help" for help.

postgres=#

I have figured out how to create a database named “mydb” and a user “admin” such that:

postgres=# \du
 Role name |                 List of roles Attributes       | Member of 
-----------+------------------------------------------------
 admin     | Superuser, Create role, Create DB              | {}
 postgres  | Superuser, Create role, Create DB, Replication | {}

I have not figured out how to make sure that user “admin” can connect to the “mydb” database – perhaps someone with such privileges doesn’t need to? [As I write, I notice that I should probably revoke Superuser privileges from admin.]

And what I really want to know is how to connect from a regular user’s shell:

$ psql -U postgres
psql: FATAL:  Peer authentication failed for user "postgres"

There are surely unwritten assumptions about running postgreSQL that I’m misunderstanding, but a couple of hours of searching, looking at tutorials, etc., has not solved the problem. I’ll be perfectly happy if someone says this has already been answered, especially if it has. I assume and hope that the answer is simple and appreciate your help.

Thanks,
ge

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1 Answer

  1. Editorial Team

    From the error-message, it seems that the authentication-settings have not been properly set.

    Besides the settings in the database itself, PostgreSQL also uses a configuration file (pg_hba.conf) that specifies what authentication-mechanisms can be used per user, host and database. You can specify that users can only connect via password/md5 password or even ‘no authentication required’

    Currently your configuration probably uses ‘Peer’ authentication for all users, which simply means: Only allow that user if it is the currently logged-in user (e.g. your shell-user should also be called ‘admin’). From your question, this is not what you want, you’ll probably want to use password or md5 authentication mechanism.

    I think these pages will give you the answer you need:

    http://web.archive.org/web/20131001194046/http://blog.deliciousrobots.com/2011/12/13/get-postgres-working-on-ubuntu-or-linux-mint/ (archived version)

    Official documentation:

    http://www.postgresql.org/docs/current/static/auth-pg-hba-conf.html

    Remember to reload postgresql after modifying the pg_hba.conf file!

    update

    The original blog-post I referred to is now offline, the link now points to an archived version. Thanks to @O_the_Del for reporting.

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