Analyzing the impact of new indexes on other SQL statements before permanently creating them on your database is essential. While improving the performance of one SQL statement, new indexes may degrade the performance of others.
First, generate or create the Index candidates for your original SQL statement in the Index Advisor window and determined which Index Set(s) give you the most performance for your SQL statement. Before performing the Index Impact Analysis function, you must save the SQL statements that may be impacted by the creation of new indexes in the SQL Repository or SQL Scanner.
To analyze the impact of creating the new indexes
In the Index Advisor window, select the bottom-left pane of the Index Set tab for the indexes that you want to analyze.