PostgreSQL Roles and Attributes

Roles and Authentication / Guide 16 of 47 / Beginner

• OSUbuntu 26.04 LTS
• PostgreSQL18.6-0ubuntu0.26.04.1
• Authscram-sha-256
• TimeAbout 13 min

CREATE USER still exists and is exactly CREATE ROLE ... LOGIN. The two-word distinction in older documentation describes syntax, not two kinds of object.

This guide includes

Use this because PostgreSQL has one object where other databases have two. This matters because a role is a user when it can log in and a group when it cannot - and the LOGIN attribute is the entire difference.

• listing roles and their attributes with \du
• reading the same thing from pg_roles, which is the queryable form
• trying to log in as a role with no LOGIN attribute, and being refused

Before you start

• A superuser connection - sudo -u postgres psql.

1. 1

   List the roles and read their attributes

2. 2

   Read the same thing from the catalogue

3. 3

   Try to log in as a role that cannot

Official sources

• PostgreSQL 18 Documentation - Database Roles
• PostgreSQL 18 Documentation - The pg_hba.conf File
• PostgreSQL 18 Documentation - Password Authentication
• PostgreSQL 18 Documentation - Privileges
• PostgreSQL 18 Documentation - ALTER DEFAULT PRIVILEGES