Siebel Analytics Performance Tuning Guide > The Database Servers > Periodic Tuning Tasks >

Drop Indexes


Indexes can greatly improve query performance and are among the most effective means to improve query performance. They should always be considered in a data warehousing environment which is a "read-mostly" environment. Nevertheless, indexes do incur significant costs, and you should drop any indexes which are not being used by queries.

Indexes incur the following costs:

Which Indexes Are Used

You can determine whether queries are using an index with tools provided by database vendors. You can use the EXPLAIN PLAN command to determine whether a specific query uses an index. You can reduce the time require when you follow this approach by looking at a representative sample of you queries.

Oracle 9i Databases

Oracle includes an ALTER INDEX MONITORING USAGE command that collects statistics over a period of time. The most effective approach is to monitor your query workload during a representative interval.


 Siebel Analytics Performance Tuning Guide 
 Published: 18 April 2003