Which statement about Automatic Memory Management with Oracle 11g is true?
A.
You cannot specify MEMORY_TARGET if you explicitly specify SGA_TARGET or PGA_AGGREGATE_TARGET values that are greater than zero in your parameter file.
B.
Oracle can reallocate memory between the SGA and PGA automatically as needed.
C.
To use Automatic Memory Management, you must explicitly set both the MEMORY_TARGET and MEMORY_MAX_TARGET parameters in your parameter file.
D.
You can set the MEMORY_TARGET parameter to a maximum value of the current SGA size plus the current PGA size.
Explanation:
When Automatic Memory Management is enabled in Oracle 11g, Oracle can reallocate memory between the SGA and PGA automatically as needed. Using Automatic Memory Management can reduce the chances of being unable to allocate memory to SGA and PGA memory structures. You can enable Automatic Memory Management by setting the MEMORY_TARGET initialization parameter or using Enterprise Manager.
The option that states you cannot specify MEMORY_TARGET if you explicitly specify SGA_TARGET or PGA_AGGREGATE_TARGET values that are greater than zero in your parameter file is incorrect. If you explicitly set SGA_TARGET and PGA_AGGREGATE_TARGET, the MEMORY_TARGET value will default to the sum of the two, but can be increased up to the value of MEMORY_MAX_SIZE. If you set MEMORY_TARGET, you can also set SGA_TARGET, PGA_AGGREGATE_TARGET, both SGA_TARGET and PGA_AGGREGATE_TARGET, or neither of the two.
How Oracle manages memory and sets the defaults for other memory parameters depends on which parameters you specify. If you set only the MEMORY_TARGET, and leave the SGA_TARGET and PGA_AGGREGATE_TARGET parameters unset, Oracle automatically allocates 60 percent of available memory to the SGA and 40 percent of available memory to the PGA when the database starts. If you set MEMORY_TARGET and PGA_AGGREGATE_TARGET but not SGA_TARGET, SGA_TARGET is set to either the SGA_MAX_SIZE value or the value of MEMORY_TARGET – PGA_AGGREGATE_TARGET, whichever is smaller. If you set MEMORY_TARGET and SGA_TARGET but not PGA_AGGREGATE_TARGET, PGA_AGGREGATE_TARGET is set to a value of MEMORY_TARGET – SGA_TARGET.
The option that states to use Automatic Memory Management you must explicitly set both the MEMORY_TARGET and MEMORY_MAX_TARGET parameters in your parameter file is incorrect. You only need to set MEMORY_TARGET. If you specify a nonzero value for MEMORY_TARGET and do not set MEMORY_MAX_TARGET, MEMORY_MAX_TARGET will be set to the same value as MEMORY_TARGET by default.
The option that states you can set the MEMORY_TARGET parameter to a maximum value of the current SGA size plus the current PGA size is incorrect. You can increase MEMORY_TARGET up to the value of MEMORY_MAX_SIZE.