SQL Tuner provides an easy and optimal way to discover efficient paths for queries that may not be performing as quickly or as efficiently as they could be. Tuner enables the optimization of poorly-performing SQL code through the detection and modification of execution paths used in data retrieval. This is primarily performed through hint injection, and index and statistics analysis.
For example, different joining methods such as nested loops or hash joins can be used and will be tested, as appropriate. Tuning will select alternate paths, and enable you to change the original path to one of the alternates. Execution paths slower than the original path are eliminated, which enables you to select the quickest of the returned selections and improve query times, overall.
This enables the DBA to correctly optimize queries in the cases where the native optimizer failed.