> is there a possibility for creating views or temp tables in memory to
> avoid disk io when user makes select operations?
you might also want to look into "materialized views":
http://jonathangardner.net/PostgreSQL/materialized_views/matviews.html
http://www.varlena.com/varlena/GeneralBits/64.php
this helped us alot when we had slow queries involving many tables.
cheers,
thomas