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SQL Optimizer for DB2 LUW 4.4.1 - Release Notes

About Index Impact Analyzer

About Index Impact Analyzer

The Index Impact Analyzer analyzes the performance impact of new indexes on SQL statements before the indexes are permanently created on your database. New indexes may improve the performance of one SQL but downgrade the performance of several others. The Index Impact Analyzer evaluates the performance effect that given indexes might have on SQL statements, thereby removing the uncertainty associated with index creation.

The Index Impact Analyzer analyzes the performance impact of index creation on SQL statements retrieved from the SQL Repository or the SQL Scanner. To analyze the impact that creating new indexes might have on SQL performance, the proposed indexes are created as virtual indexes on the database. Then new access plans are retrieved showing the impact the new indexes would on the access plans of individual SQL statements. The virtual indexes are dropped after the retrieval of the access plans.

After the analysis is complete, the Index Impact Analyzer provides metrics of the overall performance changes and allows you to identify which SQL statements have changes to access plan with the proposed indexes.

 

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