Re: To fragment or not to fragment - opinions requested

In article <43abr6$1emk@news.gate.net> miles@gate.net "Robert D. Miles" writes: > On a SMP (4 processors) system is it better to fragment all of the tables > using round robin, or should the tables be put is different or the same > Dbspace? My main concern is for performance on a database that is normalized > and uses several joins on queries. Yes we will be changing the design to > de-normalize some of the larger tables as new software is developed. I think (and this is just a thought, mind! :-), that you should have a look at your main queries and see if you can't determine an expression for fragging that would allow you to scan in parallel. It's a bit involved, so I'm going to opt out and suggest that you look in the Performance Tuning manual for 7.1, as I'm sure Informix would sue me for a copyright breach if I just quoted huge chunks of it on the 'net! :-) In general, I wouldn't advise round robin *or* putting them in the same dbspace for a large table (unless you have a specific set of circumstances). If the table is split according to an expression, the optimiser has a better idea of where to find specific sets of records. HTH, Spokey the Wheeler------------------------------------------------------------- "Billy Boy" - das aufregend andere kondom! Carter - the Unstoppable Sex Machine / Wheeler - the Unstoppable Mail Machine!