The database analysis utility, PROUTIL DBANALYS, generates table and index storage information. You should run this utility at least once every three months. You can run this utility while users are accessing the database with low-to-moderate impact on performance. Use the utility's information to determine if you must rebuild your indexes or if you need to make modifications to your database structure.
The database analysis report details table storage information and helps you determine if tables must be moved to other areas or reorganized to reduce scatter. However, the area of index utilization is generally more dynamic and must be analyzed on a regular basis.
Index efficiency is important. If your data is 100 percent static, then you want your index utilization to be 100 percent to provide you with the maximum number of index entries per block. Unfortunately, this is not the case with most applications. Most applications perform substantial numbers of inserts and modifications, which impact the indexes. You should have sufficient space left in the index blocks to add additional key values without introducing the need for an index block split.
