Joined: 14 Mar 2007 Posts: 8657 Location: Back in jolly old England
In addition to the thread linked to by murmohk1
With speed, cahing and read ahead algorithms of modern DASD subsystems, there will be little if any performance benefit from doing a reorg of a KSDS. Maybe if it reduces the number of index levels being used by the KSDS, byt that is quite a rare occurance too.
So, if your KSDS is nearing its 123 extent limit, that's the time to think about a reorg.