Performance gains through query optimization

The Adaptive Server optimizer attempts to find the most efficient access path to your data for each table in the query, by estimating the cost of the physical I/O needed to access the data, and the number of times each page needs to be read while in the data cache.

In most database applications, there are many tables in the database, and each table has one or more indexes. Depending on whether you have created indexes, and what kind of indexes you have created, the optimizer’s access method options include:

Having the proper set of indexes on your tables should allow most of your queries to access the data they need with a minimum number of page reads.