Which two statements are true regarding the SGA_TARGET initialization parameter?
(Choose two.)
A.
It can be increased up to the value of the SGA_MAX_SIZE parameter.
B.
Increasing the value of the SGA_TARGET parameter distributes the increased memory
among all theautotuned components.
C.
Reducing the value of the SGA_TARGET parameterdeallocates memory from both
autotuned and manually sized components.
D.
Increasing the value of SGA_TARGET up to the value of SGA_MAX_SIZE disables the
automatic shared memory management feature.
SGA_TARGET specifies the total size of all SGA components. If SGA_TARGET is specified, the following memory pools are automatically sized:
• Buffer cache (DB_CACHE_SIZE)
• Shared pool (SHARED_POOL_SIZE)
• Large pool (LARGE_POOL_SIZE)
• Java pool (JAVA_POOL_SIZE)
• Streams pool (STREAMS_POOL_SIZE)
If these automatically tuned memory pools are set to nonzero values, the values are used as minimum levels by Automatic Shared Memory Management (ASMM). You set minimum values if an application component needs a minimum amount of memory to function properly.
The following pools are manually sized components and are not affected by ASMM:
• Log buffer
• Other buffer caches (such as KEEP and RECYCLE) and other block sizes
• Fixed SGA and other internal allocations
The SGA_TARGET parameter can be dynamically increased up to the value specified for the SGA_MAX_SIZE parameter, and it can also be reduced. If you reduce the value of SGA_TARGET, the system identifies one or more automatically tuned components for which to release memory. You can reduce SGA_TARGET until one or more automatically tuned components reach their minimum size. Oracle Database determines the minimum allowable value for SGA_TARGET taking into account several factors, including values set for the automatically sized components, manually sized components that use SGA_TARGET space, and number of CPUs.
The change in the amount of physical memory consumed when SGA_TARGET is modified depends on the operating system. On some UNIX platforms that do not support dynamic shared memory, the physical memory in use by the SGA is equal to the value of the SGA_MAX_SIZE parameter. On such platforms, there is no real benefit in setting SGA_TARGET to a value smaller than SGA_MAX_SIZE. Therefore, setting SGA_MAX_SIZE on those platforms is not recommended.
On other platforms, such as Solaris and Windows, the physical memory consumed by the SGA is equal to the value of SGA_TARGET.
ANSWER: A,B