View the Exhibit to examine the output produced by the following query at three different times
since the database instance started and has experienced workloads of different capacities:
SQL> SELECT substr(component, 0, 10) COMP, current_size CS, user_specified_size US FROM
v$memory_dynamic_components WHERE current_size!=0;
What do you infer from this?
A.
The database instance is running with manual PGA management.
B.
The database instance is running with manual shared memory management.
C.
The database instance has the MEMORY_TARGET value set to a nonzero value.
D.
All sessions are connected to the database instance in dedicated mode, and no RMAN or parallel
query operations have been performed.
Exhibit not showing
Dynamic performance view V $ MEMORY_DYNAMIC_COMPONENTS, shows the current size of all the dynamic optimization of memory components , including the total size of the SGA and instance PGA .
Three times the size of the various components of the SGA to start are the same , is dynamic , PGA is dynamic , so the database is in automatic memory management is the AMM, MEMORY_TARGET.
So we know Memory_target is set to a nonzero value.
MEMORY_TARGET specifies the Oracle system-wide usable memory. The database tunes memory to the MEMORY_TARGET value, reducing or enlarging the SGA and PGA as needed.
In a text-based initialization parameter file, if you omit MEMORY_MAX_TARGET and include a value for MEMORY_TARGET, then the database automatically sets MEMORY_MAX_TARGET to the value of MEMORY_TARGET. If you omit the line for MEMORY_TARGET and include a value for MEMORY_MAX_TARGET, the MEMORY_TARGET parameter defaults to zero. After startup, you can then dynamically change MEMORY_TARGET to a nonzero value, provided that it does not exceed the value of MEMORY_MAX_TARGET.
If memory_target is set, then AMM is enabled
Three times the size components of the SGA to start are the same, PGA is dynamic, so we know the database is in automatic memory management (AMM).
This is due to the fact that MEMORY_TARGET was set to nonzero value.