Role Hierarchy

Hi,
I am using PostgreSQL 8.1 . I am trying to print all the roles in a hierarchy. For example

r1
|
r2 r3
| |
-------
|
r4
|
r5

Here r5 is member of r4 , r4 is member of r2 and r3 and r2 is member of r1. Now in a query if i give role name as 'r5' it has to display the entire hierarchy. For this I am trying with the following query but it just printing the immediate hierarchy only.
The query is as following :

select pr.rolname from pg_roles pr
LEFT JOIN pg_auth_members pam
ON(pr.oid=pam.roleid)
LEFT JOIN pg_roles pr1
ON (pam.member=pr1.oid)
WHERE pr1.rolname='r4';

I need a solution for this problem.

Regards,
Prakash.

Hi Prakash, did you ever find the solution for that ?

I'm having the same problem to solve, so I'd be interested to know the answer.

Thanks,

Sebastien