Ok.
Big thanks for the information.
You mentioned Bizgres, do you have any more information in that direction, or do you know who to contact regarding information on Bizgres bitmap indexes. If there is a bitmap index patch in Bizgres which can be applied to the latest stable source of PostgreSQL then I have a solution until 8.4 (which I according to your answers is the assumed release for introducing on-disk bitmap indexes).
Any guess when 8.4 could be production ready? A year or more?
Regards,
Christian