performance degrade after upgrade fron 8.1.7 to 9.2.0

[dbasan]

Hi all,
One of the suggestion is that revert this parameter back to 8.1.7. My question is what can we do if we want to leave this parameter in 9.2.0.

1. You can wait for the statspack report, then troubleshoot.
2. reverting back the parameter to 8.1.7, will get back the optimizer settings(oracle recommends to have the same old settings then after careful analysis set the paramenter to the new version).
3. Check the Oracle docs on the enhancements to 9.2.0, with the statspack report do the required tuning to get the expected performance.