Re: To fragment or not to fragment - opinions requested (fwd)

Not to contridict what the trainers tell you, but the fragmentation scheme depends upon the nature of your business. round robin works well for some oltp applications as well as some dss applications. It is best when you do not know the distributions of your data or you want to achieve the best random i/o possible. expression based is good for when you know the distributions of your data. Any fragmentation scheme needs to have someone to watch it periodically so that it does not fall out of touch with your data. > > The approach recommended in the Informix DBA Class was not to use round > robin but fragmentation "BY EXPRESSION". This should be done across DBSPACE > to have a balance in the data. > > On Thu, 14 Sep 1995, Robert D. Miles wrote: > > } 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. > } > } Currently the database has about 150 million rows and is growing. > } > } An input on the trade offs of using fragmentation or not will be appreciated. > } > } > } Bob > } > } Informix version 7.10 > } > -- Dave Proksch - DBA - ValueRx - Phone: (810) 333-8622 Fax: (810) 253-6510 email: dproksch@vrx.vhi.com snail mail: 1825 South Woodward Suite 200 Bloomfield Hills, MI 48302 USA #include <std_disclaimer.h>