RE: Simple cluster index question (sorry, I'd RTFM, but don't hav

Correct, it alters the physical ordering of the rows to conform with the index. Once done, though, Informix does make any assumptiions regarding the continued ordering of the rows. Obviously, for performance improvement, it is best for the table to be static in its data. What I have found to be the most common use of clustering an index is in reclaiming disk space from a table. Since the table is rebuilt (another copy is created, then the old table dropped), a table which has a lot of "holes" in it is put back in one extent and takes up only as much room as necessary for the data. > -----Original Message----- > From: Danny Wright [SMTP:danwright@bigfooot.com] > Sent: Friday, January 21, 2000 8:25 PM > To: informix-list@iiug.org > Subject: Simple cluster index question (sorry, I'd RTFM, but don't > have a copy w/ > > I just wanted to know if I was misinformed (or if Informix has changed) > the way clustered indices work. > > If memory serves correctly, it alters the physical ordering of rows > within a table.... > > however, updates and inserts could cause the order to be incorrect, thus > making this a not too brilliant thing to do with a table whose data will > change frequently. > > > If I'm right so far, will Informix assume the index is still clustered > and valid and possibly return rows in the incorrect order or perhaps not > at all (since it's making assumptions about the physical order?). > > > Thanks in advance