flexi auth - A user authentication library for CodeIgniter

[eluser]Unknown[/eluser]
Hi everybody

Starting to work with Flex Auth. I'm interesting in how db indexes are placed.

Table 'user_groups'
- why to use 2 indexes, both on 'ugrp_id'

Table 'user_login_sessions'
- the same situation, but index is placed on varchar column

Table 'user_privilege_groups'
- indexes are placed on all columns.

I'm using clear, just downloaded version of Flex Auth.