Вы можете запросить системные таблицы:
SELECT proname, rolname
FROM pg_proc pr,
pg_type tp,
pg_authid id
WHERE proowner = id.oid
AND tp.oid = pr.prorettype
AND pr.proisagg = FALSE
AND tp.typname <> 'trigger'
AND pr.pronamespace IN (
SELECT oid
FROM pg_namespace
WHERE nspname NOT LIKE 'pg_%'
AND nspname != 'information_schema'
);