Instance Profile settings in Performance Analysis (PA) Agent Administration (45399)

Are the settings below needed to be set by the user or is it automatically detected by Performance Analysis (PA)?

PAO | Agent Administration | Advisories | Instance Profile
- Available RAM in MB
- Transaction Type
- Datafile disk devices
...

1. For the Available RAM in MB, does it mean the amount of memory assigned to Oracle, say the "sga_max_size" parameter in Oracle?

2. When does PA calculates initialization values, after setup?

3. If the user change these Oracle configurations afterward, does the user need to modify these setting values accordingly in the instance profiler?

4. Does these settings affect the advisories recommendation?

1. Available RAM in MB refers to the physical memory (RAM) available for use by this database. This information is available in the help file (Instance Profile, hit F1).

2. The instance profiler address Advisories. PA calculates initialization values for the profiler and subsequently, the user can go ahead and modify these values.

Initial values:
Available RAM in MB - calculating sga size plus 1.2 MB per session
Transaction Type - 3 (Mixed - most general)
Datafile disk devices - number of datafiles paths, setting minimum to 2
Datafile RAID Status - 0
Dedicated redo devices - 0
Alternated redo devices - checking if there is more than one redo file path. If yes - 1, no - 0
Dedicated archive devices - 0

3. The initialization values are set after setup. We assumed the customer understand his environment best and he can change the instance profiler accordingly. This is not a must, though as explained PA can keep on working with the initialization parameters.

The data is accurate even if you do not update these settings. It's resolution (advisories are updated; much like data aggregation) might change a bit but that's all. For example, if db buffers resources was changed then it depends on the scan rate and the advisory will give a recommendation accordingly. This is the same with top sql that PA displays; it won't show you all sql running in the instance, but will focus on the most excessive ones. Just like a baseline, instance profiler keeps "learning", so the data will always be accurate. The only difference (which is not that significant) will be in the resolution.

4. The advisories will be accurate. Changing the parameters can ease the Advisories work. For example, increasing the RAM (more memory and a smaller resolution time will give better results), etc. Leaving the instance profiler as it is will work just fine. The parameters in the instance profiler influence the Advisories resolution. The impact won't be that significant, but the best way to know is to change the parameters and observe.