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The hint syntax was included in Oracle syntax as a way to handle exceptional
situations, rather than to allow you to circumvent the query optimizer. If you??™ve found
a performance anomaly and further investigation has led to the discovery that the
query optimizer is choosing an incorrect execution path, then and only then should
you assign a hint to a query.
Even in this situation, we recommend that you keep an eye on the hinted query in a
production environment to make sure that the forced execution path is still working
optimally.
118 | Chapter 4: Oracle Data Structures
Once these statements are identified, SQL*Analyzer executes the SQL in each environment
and provides feedback on the performance and resource utilization for
each. Although SQL*Analyzer cannot avoid potential problems brought on by optimizer
upgrades, the tool can definitely simplify an otherwise complex testing task.
Oracle Database 11g also includes a feature called Database Replay. This feature
captures workloads from production systems and allows them to be run on test
systems.


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