Troubleshoot Optimization Results
After you optimize the original SQL statement and determine the best alternatives, you may find the performance of the selected statements unsatisfactory in your database environment.
Make adjustments to the intelligence, optimization, SQL options, or quota setting options if SQL Optimizer has reached any of the quotas. To access these settings, click 
Additionally, review the execution plan of the original and optimized SQL statements to check if you need to change the database structure.