The index compact utility, PROUTIL IDXCOMPACT, is the online substitute for index rebuild. Run this utility when you determine that the indexes are not as efficient as desired and the database cannot be taken offline to perform an index rebuild. You can determine inefficiencies by reading the output of the database or index analysis utilities.
The benefit of the index compact utility over index rebuild is that it can be run with minimal performance impact while users are accessing the database. The resulting index efficiency is usually not as good as a sorted index rebuild, but the cost saving from eliminating downtime, and the minimal performance impact generally make this the preferred option.
The index compact utility allows you to choose the level of compression that you want for your index blocks. The default compression level for this utility is 80 percent—ideal for nonstatic tables. If your tables are static, you might want to increase the compression level. You can not choose a level of compression that is less than your present level of compression.
