Re: Summary tables feature in Informix Advanced Decision Support

Sounds like you're talking about metacube - maybe they've renamed it. I am no expert in the product, but I seem to remember that Metacube maintains statistics on queries and then makes recommendations on what summary tables to build. Whether it keeps these summary tables up to date I do not know - it DOES have an agent to run tasks of that nature. It will re-direct your query against a fact table towards a more appropriate summary table at execution time. That said you might try contacing Mike Wilkes from the metacube group (I think it's Mike Wilkes) for better info. His email is mwilkes@informix.com cheers j. "David Sisk" <davesisk@ipass.net> on 08/12/98 10:30:35 PM Please respond to "David Sisk" <davesisk@ipass.net> To: informix-list@iiug.org cc: (bcc: Jack Parker/Boston50/Epsilon) Subject: 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