Re: Fragmentation opinion wanted.

Chuck Renaud wrote: > > There are two things you try to achieve with fragmentation: > > 1. Parallelism > 2. Fragment elimination No. There is one aim with fragmentation (partitioning) and that is to balance IO. That does not always include fragment elimination. If you are loading data, then round robin will give you a better balance of IO than expression based. If you have a lot of users attacking various records, then expression based may well give a better balance of IO than round robin. > Since hardware likely doesn't know what the data looks like, it isn't > going to be much help with either of those. Agreed. > It doesn't mean you can't use hardware to help distribute I/O...but it can > probably be better used with an effect Informix fragmentation strategy. > > I can provide a couple of examples if you'd like... > > --Chuck > > On Thu, 9 Mar 2000, Paul Howard wrote: > > > We have IDS 7.31 and AIX 4.3 > > > > I am being told by my software vendor that I should not fragment tables using > > Informix > > fragmentation. They say that it would be better for me to optimize my system by > > spanning dbspaces across multiple disks and letting the hardware fragment the > > table. Perhaps they are used to flat file databases. Which means they are used to optimising file systems, for which this strategy works very well. Which S/W vendor? Baan? SAP? PeopleSoft? :-) > > This is contrary to my experince and schooling. Can anyone tell me how much merit > > this > > statement of my software vendor has? If they have a database design which is more flat file than relational, then they may be right. If they are not supplying a database, then you are probably better going with intelligent striping (fragmentation) rather than blanket striping. Cheers, -- Mark. +----------------------------------------------------------+-----------+ | Mark D. Stock mailto:mdstock@mydas.freeserve.co.uk |//////// /| | http://www.informix.com http://www.informixhandbook.com |///// / //| | http://www.iiug.org +-----------------------------------+//// / ///| | |What year 2000 bug? year 2000 bug? |/// / ////| | |year 2000 bug? year 2000 bug? year |// / /////| | |2000 bug? year 2000 bug? year 1900 |/ ////////| +----------------------+-----------------------------------+-----------+