pg_user_mapping

The system catalog table pg_user_mapping stores the mappings from local user to remote user. You must have administrator privileges to view this catalog. Access to this catalog is restricted from normal users, use the pg_user_mappings view instead.

column type references description
umuser oid pg_authid.oid OID of the local role being mapped, 0 if the user mapping is public.
umserver oid pg_foreign_server.oid OID of the foreign server that contains this mapping.
umoptions text[]   User mapping-specific options, as “keyword=value” strings.

Parent topic: System Catalogs Definitions