How to enumerate all enabled roles for all users in PostgreSQL?

Question

If you want to check the roles that a user has access to, there is no easy way in PostgreSQL. In the information_schema there are relations enabled_roles

Answer 1

This was very helpful as I was looking for just this sort of information. Adapting the work above to include a level to keep track of the inheritance

WITH RECURSIVE membership_tree(grpid, userid, lvl) AS (
-- Get all roles and list them as their own group as well
SELECT 
    pg_roles.oid
    , pg_roles.oid
    , 0
FROM
    pg_roles

UNION ALL

-- Now add all group membership
SELECT 
    m_1.roleid
    , t_1.userid
    , lvl + 1
FROM
    pg_auth_members m_1
INNER JOIN
    membership_tree t_1 
ON
    m_1.member = t_1.grpid
)
SELECT DISTINCT
    t.userid
    , r.rolname AS usrname
    , t.grpid
    , m.rolname AS grpname
    , t.lvl
FROM
    membership_tree t
INNER JOIN
    pg_roles r
ON
    t.userid = r.oid
INNER JOIN
    pg_roles m
ON
    t.grpid = m.oid
ORDER BY
    r.rolname
    , t.lvl
    , m.rolname;