Summary tables feature in Informix Advanced Decision Support Option

Hello: Would someone be so kind as to email me a brief synopsis of the summary tables feature in the advanced decision support option? I'm assuming that, since you can create, populate, and use a summary table manually, this feature makes some of those tasks happen automagically (since this option isn't free). Specifically, does it: 1) Allow the optimizer to detect when a query that performs a select against a large fact table can be satisfied by re-directing it to a smaller summary table? Or do you explicitly have to code the SQL to select from the summary table (if so, doesn't seem too useful :=>). 2) Allow the database process itself to maintain the data in the summary table(s) based on changes to the fact table? Or, do you have to code triggers or stored procedures to maintain the data in the summary tables? In other words, would a summary table constructed using this feature remotely resemble an index rather than a table (ie. maintained by the database and the optimizer is aware that it exists and when it can be used rather than the fact table)? Any details or comments on how this feature is supposed to work and how it actually works in practice would be tremendously appreciated. Doubly thankful if you would respond via email as well as posting here. Thanks and regards, Dave