The Index Usage Analyzer identifies unused indexes by analyzing access plans from SQL statements in your database applications. It examines their access plans and reports any indexes in the database that are not used. You can use this module to quickly identify the indexes in databases that are not contributing to the performance of the database applications. These unused indexes can then be deleted to free up space and improve the speed of the database applications and maintenance.
The Index Usage Analyzer identifies:
Tables that are referenced in the SQL statements
Indexes in each table that are used in the access plans, and the number of referenced SQL for each index
Indexes in each table that are not used in the access plans
The selected SQL statements that the Index Usage Analyzer analyzes are from SQL that you have saved in the SQL Repository or SQL statements from the SQL Scanner.
Quest SQL Optimizer for IBM® DB2® LUW maximizes SQL performance by automating the manual, time-intensive and uncertain process of ensuring that SQL statements are performing as fast as possible. SQL Optimizer analyzes, rewrites, and evaluates SQL statements within multiple database objects, files. With SQL Optimizer, you can analyze and optimize all your problem SQL from multiple sources. SQL Optimizer also provides you a complete index optimization and plan change analysis solution, from index recommendations to simulated index impact analysis, through comparison of multiple SQL access plans.
SQL Optimizer provides you with the following main modules.
SQL Optimizer (including SQL Rewrite and Generate Indexes functions)
The Index Usage Analyzer window displays the information about the SQL statements that are saved in the Index Usage Analyzer. The display in the right section of the window depends on what is selected in the left pane.
Always displays a tree diagram of the Analyzers and the folders they are stored in.
The right pane displays a variety of different information depending upon what is selected from the tree diagram in the left pane.
You can display information for the following:
In the Index Usage Analyzer window, when an Analyzer is selected in the left pane, the following information is displayed in the right pane.
Displays the total number of indexes in the tables used in all the selected SQL statements and the number of used and unused indexes. Charts the percentage of the indexes that are used by the access plans for the selected SQL statements.
The detailed information about the Analysis is displayed in the button pages. The buttons for displaying specific information are found at the top of this pane.
Displays general information about the analysis, information on the connection used to retrieve the access plans and the SQL statements used in the analysis.
Displays the indexes that are used by the selected SQL statements in black text and highlights in red the indexes that are not used.
To save a list of all the unused indexes
Right-click and select Save.
In the Save Format window, select Text, HTML, or Excel Convertible (Spreadsheet).
To drop an index
Right-click the line with the index you want to drop and select Drop Index.
