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 you have finished collecting and editing your tuning data, Oracle Expert can analyze the data and generate tuning recommendations. Select the Analyze page of the tuning session window and examine the session status to confirm that you have provided Oracle Expert with the appropriate data for the tuning session. The Analyze page shows you the information that Oracle Expert will analyze if you click the Perform Analysis button at the bottom of the page.
The Analyze page displays the following information:
This field displays the date of the last analysis for this tuning session. If Oracle Expert has never analyzed the collected data, the word "Never" is displayed.
Displays the tuning categories selected for the tuning session.
Lists the data that has been collected and made available for Oracle Expert to analyze.
Note that when Environment class data is entered manually, Oracle Expert does not update the date and time in the Last Collection column for the Environment class. When Environment class data is collected from an .XDL file, Oracle Expert does update the date and time in the Last Collection column for the Environment class.
Displays the Oracle Expert control parameters and their current settings.
When you are doing access methods tuning and before you begin an analysis, consider how you would like Oracle Expert to provide index recommendations on the Review Recommendations page of the tuning session window and in the Analysis report. Then set the value of the "Index summary style" rule accordingly. By default, the "Index summary style" rule is set to 2, which means only the final index analysis recommendations are provided.
If you want Oracle Expert to provide all of the index analysis recommendations it generates during the analysis, you can change the value of the "Index summary style" rule to 1 prior to the analysis. If you do, Oracle Expert will provide all of its index analysis recommendations (not just its final index analysis recommendations) on the Review Recommendations page and in the Analysis report after the analysis is done.
For example, Oracle Expert may recommend an index be created on a particular column because of several SQL statements that access the column. However, if later in the analysis Oracle Expert determines that the relative importance of the SQL statements is not high enough to justify the new index, Oracle Expert will generate another recommendation to delete the index. As another example, Oracle Expert may recommend a new index on a column based on SQL statements that access the column. However, if Oracle Expert determines later in the analysis that the "Workload Class" control parameter is set to OLTP or BATCH (both of which are update-intensive, which means the originally recommended index would slow down performance), Oracle Expert may recommend that the index be deleted.
Note that the setting of the "Index summary style" rule determines how the index analysis recommendations are provided on the Review Recommendations page and Analysis report, but not any intermediate index recommendations that may be considered, and later ruled out, during the course of the analysis. An example would be if Oracle Expert decided that table A required an index on column B but later determined that this index was not important enough to implement.
The "Index summary style" rule can be set for database, schema, or index objects on the View/Edit page of the tuning session window. Select the object, choose Edit=>Modify, select the Rules tab, then the Index Analysis tab, and provide the desired value for the rule. For more information about changing rule values, see "Rules Page".
When you click the Perform Analysis button, Oracle Expert begins its analysis of the collected data and:
After an analysis is complete, you can examine the tuning recommendations on the Review Recommendations page. Note that Oracle Expert considers the interdependencies between recommendations while generating the list of recommendations for an analysis. If you use all the recommendations from an Oracle Expert analysis, you will be implementing the best overall Oracle Expert tuning recommendations for your database for the tuning categories you selected, based on the collected data provided for the analysis. Select the Review Recommendations tab of the tuning session window to display the Review Recommendations page. For more information about reviewing tuning recommendations, see "Reviewing Tuning Recommendations".
For complete information about the Oracle Expert recommendations and justifications for them, choose Report=>Analysis to generate an Analysis report.
Before performing an analysis, Oracle Expert looks at the tuning categories you have selected for the tuning session. Then, during the analysis, Oracle Expert analyzes only the collected data that it requires to generate recommendations for the selected categories. This means, for example, if you select the SGA tuning category for a tuning session, Oracle Expert excludes collected Schema or Workload class data from the analysis because Oracle Expert does not use schema or workload data when making SGA tuning recommendations.
Depending on the goals of your tuning session, you can sometimes reduce the amount of data Oracle Expert analyzes by excluding objects from an analysis. This reduces the amount of data Oracle Expert analyzes and the time Oracle Expert spends analyzing the data and generating tuning recommendations. In general, if you do not want Oracle Expert to generate recommendations for all of the collected objects of a particular type, you can choose to exclude objects from the analysis. To exclude an object, either set the object's Tunable rule to Disabled or delete the object.
The Tunable rule is another name for the "Enable or disable tuning for the current object and its children" rule, which is a Common rule available for some of the objects that you collect during a tuning session. An object's Tunable rule value (either Enabled or Disabled) determines whether or not the object is included in an Oracle Expert analysis. If the Tunable rule is not available for an object or you do not explicitly set a value for its Tunable rule, Oracle Expert uses the value of the rule from the next higher level of the View/Edit page hierarchy where the rule is instantiated (or the default value of the rule, if none of the higher objects in the hierarchy have instantiated the rule). If you explicitly set the Tunable rule value for an object, Oracle Expert uses that value for the Tunable rule. The default value of the Tunable rule for all objects is Enabled.
A tuning session analysis excludes objects with a Tunable rule value of Disabled. Oracle Expert does not generate any tuning recommendations for these objects.
Suppose you select the Access Methods tuning category for a tuning session because you want Oracle Expert to determine if a particular table is properly indexed. To perform Access Methods tuning, Oracle Expert requires that Schema class data be collected for the schema that includes the table for which you want recommendations (see Table 5-2). However, because you are interested in recommendations on only a single table, you can exclude the other tables in the schema from the analysis (by setting the Tunable rule's value to Disabled for the tables for which you do not want recommendations).
As another example, suppose you select the SQL Tuning category for a tuning session because you want Oracle Expert to tune the SQL statements for two applications. To perform SQL tuning, Oracle Expert requires that Workload class data be collected for these applications. If you have previously collected workload data for other applications besides the two you are interested in tuning, the other applications can be excluded from the analysis. You can exclude an application from an analysis by setting the value of the application's Tunable rule to Disabled.
You can verify and change the value of the Tunable rule for an object by following these steps:
For more information about changing rule values, see "Rules Page".
Another way to exclude an object from an analysis is to delete the object. Select the object on the View/Edit page and choose Edit=>Delete.
While an analysis is in progress, you cannot:
To cancel an analysis that is in progress, choose Cancel=>Process. After confirming that you want to cancel the analysis, Oracle Expert displays a dialog box with the Continue option, which returns you to the Analyze page.
If an analysis stops due to an unexpected error, the dialog box options and their meanings are:
Returns you to the Analyze page.
Causes Oracle Expert to retry the analysis.
Exits you from Oracle Expert.
When Oracle Expert collects data for a tuning session, during the collection process it can determine that some objects are invalid. For more information about objects that are marked invalid after a collection, see "Collecting Invalid Data".
During an analysis, Oracle Expert performs additional validation and can discover other invalid objects. For example, Oracle Expert may find schema objects that refer to other schema objects that have not been collected. Oracle Expert considers a schema object to be invalid if it refers to another schema object for which data has not been collected.
The Oracle Expert Analysis report describes invalid objects discovered during the analysis. Oracle Expert includes invalid data when it analyzes tuning session data, but it does not generate any recommendations regarding invalid objects. For more information about generating an Analysis report, see "Generating an Analysis Report".
A valid analysis is one that completes without errors. If a valid analysis exists and you attempt to perform a collection or modify or delete tuning session data, Oracle Expert warns you that the operation will invalidate the analysis. You will be given a choice as to whether or not to continue with the operation. If you continue, the analysis will be marked as invalid, which means:
