DSS temp/join/sort/etc storage?

Howdy! My company has an Informix Online v5 database which is being used in a DSS application. Recently we've been looking at how much free space should be available in the database for such things as temprary tables, joins, sorts, etc. Some articales I've seen recommend a 4:1 (!) free:data ratio. My questions are: 1) Where does Online do its sorting/join/etc work? Does itdo this in memory, in /tmp, within a given dbspace? 2) What is optimum free:data ratio for a DSS application? Our data is broken down in tables by "version" instead of being huge, composite tables, so I would think this would lower the free:data ratio... 3) Is there anyway to find out how much database space a _table_ is taking up in the database? 4) Are there any good references (books, www sites, etc) that deal with DSS applications deployed on Informix? ADVthanksANCE! -Bill :) wlj@cais.com jaegerwl@wckn.dorm.clarkson.edu