Release 1.4.0
A53653_01
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| Oracle Enterprise Manager Oracle Expert User's Guide Release 1.4.0 A53653_01 |
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The topics in this chapter include:
When Oracle Expert finishes analyzing the collected data, you can select the Review Recommendations tab on the tuning session window. This displays the Review Recommendations page, where you can review the Oracle Expert tuning recommendations.
On the Review Recommendations page, recommendations of a particular type are grouped together under descriptively named folders similar to the folders on the View/Edit page. Instance rules are shown in descending order of priority. To view the recommendations of a particular type, click the plus sign (+) for the folder.
For more information about why Oracle Expert made a particular recommendation, select the recommendation and either click the View Detail button or double-click the recommendation. Details of the rationale for the recommendation will then be displayed.
When reviewing the Instance Analysis recommendations, you may decline individual recommendations. To decline a recommendation, select the recommendation and click the right mouse button, then click Toggle State. The icon next to the selected recommendation will be marked with the international No symbol. The recommendation's state can be restored by clicking Toggle State again.
When you decline a recommendation, it is wise to perform an analysis again because other recommendations may have a dependency on the declined recommendation.
When you decline a recommendation, Oracle Expert instantiates an override rule for the parameter that was declined, using the current parameter setting. For example, if the parallel_max_servers parameter is currently set to 5 and you decline the "Decrease parallel_max_servers to 0" instance recommendation, Oracle Expert instantiates the "Parallel_max_servers parameter override" rule with a value of 5 for the Parallel query parameters object.
To see the newly instantiated override rule, select the Parallel query parameters object on the View/Edit page, choose Edit=>Modify, select the Rules tab, then the parallel_max_servers tab. As long as the "Parallel_max_servers parameter override" rule is instantiated at the Parallel query parameters object level, Oracle Expert will use the current value during instance evaluation for the tuning session. If you remove the instantiation of the "Parallel_max_servers parameter override" rule, Oracle Expert will re-evaluate the parameter.
If you change your mind about declining a recommendation, toggle its state by highlighting the recommendation and clicking the right mouse button, and then selecting Toggle State. This action also removes the instantiation of the affected override rule at the instance parameter level, which means Oracle Expert can make this recommendation again during the tuning session. Once you decline any recommendations and perform an analysis, you must manually remove the instantiation of the affected override rule (as described in the previous paragraph) before Oracle Expert will re-evaluate the parameter for the tuning session.
After you decline one or more recommendations from the current analysis, another analysis should be performed to re-evaluate all recommendations because some may have a dependency on the declined recommendations. If you attempt any of the following operations, a message is displayed advising you that declined recommendations exist:
You have the option of continuing with these operations after receiving the message. Note that if you generate implementation files after declining one or more recommendations, the implementation files will contain parameters and scripts to implement all of the Oracle Expert recommendations (not just the recommendations you chose to use).
If you decline one or more of the recommendations, you can return to the Analyze page of the tuning session window and begin another analysis of the collected data. Oracle Expert will take the recommendations you declined into account, then generate new recommendations (after considering the interdependencies between the recommendations). The new set of tuning recommendations does not include the recommendations you declined.
During an analysis, Oracle Expert may generate one or more recommendations that you cannot explicitly decline (these appear as grayed-out recommendations on the Review Recommendations page) and that you do not want to implement. If so, you can change rules at the appropriate object level to influence Oracle Expert so that these recommendations are not generated during future analysis sessions, or you can manually edit the recommendations in the implementation files.
For example, suppose Oracle Expert recommends that you create a new index with 16 segments on a particular table. You may agree with the recommendation to create the index, but you do not want to create any indexes with more than 6 segments. In this situation, you can go to the View/Edit page, select the table for which Oracle Expert recommended the 16-segment index, and choose Edit=>Modify, which displays the Edit dialog box. Go to the Rules page, select the Index Analysis Parameter tab, and click the Advanced button. Find the "Maximum index key segments" rule, and change its value to 6. This will ensure that Oracle Expert recommends indexes with 6 or fewer segments for the table during future analysis sessions.
When Oracle Expert has generated recommendations you want to implement, select the Implement tab, which displays the Implement page.
To review all of the recommendations for a tuning session and the rationale for those recommendations, generate an Analysis report by choosing Report=>Analysis.
