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About the Memory Advisors

Adcquatc physical mcmory has a significant impact on thc performance of your Oracle Database. With its automatic memory managcment capabilitics, Oracle Databasc can automatically adjust the mcmory distribution among the various SGA and PGA components for optimal performance. Thesc adjustments arc madę within the boundaries of the total amount of memory that you allocate to the database. ADDM periodically evaluates the performance of your database to determine performance problems. If ADDM finds that the current amount of availabie memory inadequate and adversely affecting performance, then it can recommend that you increase memory allocations. You can select new memory allocations using the Memory Advisors.

Additionally, you can use the Mcmory Advisors to perform what-if analysis on the following:

■The database performance benefits of adding physical memory to your database ■The database performance impact of reducing the physical memory available to your database

With the Memory Advisors, you can obtain memory sizing advice as follows:

■    If automatic memory management is enabled, you can get a prediction of the percentage of time saved by using a different target memory size setting for the Oracle instance.

Sec "Modifying Memory Settings - Automatic Mcmory Management" on page 5-17 for morę information.

■    If automatic mcmory managcment is disabled and automatic shared memory management is enabled. you can get a prediction of the percentage of time savcd by using a different total SGA size.

Sec "Modifying Memory Settings - Automatic Shared Mcmory Management" on page 5-21 for monę Information.

■If only manuał shared memory management is enabled, then you can get a prediction of the percentage of reads saved by using a different database cache size.

See "Modifying Memory Settings - Manuał Shared Memory Management" on page 5-23 for monę information.