Redsfhit でユーザーとグループの一覧を確認する

select usename, usesysid, usesuper, useconfig, groname, grosysid, grolist
from pg_user, pg_group
where pg_user.usesysid = any(pg_group.grolist);

参考

• amazon web services - Redshift: How to list all users in a group - Stack Overflow