I recently had a customer case where a developer was trying to inspect the privileges granted to a specific user. We attempted to look in information_schema.table_privileges but quickly discovered that it only printed the interpreted contents of relacl in pg_class – in other words, information_schema.table_privileges does not print permissions inherited by group membership.

The Query

To view inherited permissions, we leveraged PostgreSQL’s has_table_privilege() function, one of several permissions-related functions listed in the documentation. With that, we formulated the following query:

SELECT r.rolname AS user_name,
       c.oid::regclass AS table_name,
       p.perm AS privilege_type
  FROM pg_class c CROSS JOIN
       pg_roles r CROSS JOIN
 WHERE relkind = 'r' AND
       relnamespace NOT IN (SELECT oid FROM pg_namespace WHERE nspname in ('pg_catalog','information_schema')) AND
       has_table_privilege(rolname, c.oid, p.perm);

This query will list every user and ALL the non-system tables they have privileges for, with one row for each privilege – this could be overwhelming to someone looking for information on just one user or one table. To filter the results, one can add an AND condition on rolname and/or relname.