Implementing Siebel Business Applications on DB2 UDB for z/OS > Maintenance Considerations for z/OS >
About Reorganizing Table Spaces, Partitions, and Indexes
It is recommended that you reorganize the table spaces, partitions, and indexes that have a tendency to become fragmented.
No strict guidelines can be offered as to which table spaces, partitions, and indexes might require reorganization due to the variety in application and customer operation variables at any given customer site. However, database administrators must pay attention to the status of large or heavily used table spaces and indexes, because fragmentation of these objects can affect performance significantly.
Avoid using online REORG of Siebel repository table spaces. Schedule reorganization of Siebel repository table spaces during application downtime to avoid adversely affecting the Siebel application.
After you reorganize table spaces and indexes, it is recommended that you execute rstat390 (from the midtier) or RUNSTATS (on the DB2 host). For more information on how to run these utilities, see About the RUNSTATS Utility.