The database instance was started up using the automatic memory management feature. No
value was set for the RESULT_CACHE_MAX_SIZE parameter.
Examine the following initialization parameter settings for your database:
MEMORY_TARGET = 500M
RESULT_CACHE_MODE = MANUAL
You execute a query by using the result_cache hint. Which statement is true in this scenario?
A.
The query results are not stored because no memory is allocated for the result cache.
B.
The query results are stored and 0.5% of the memory target is allocated to the result cache.
C.
The query results are stored and 0.25% of the memory target is allocated to the result cache.
D.
The query results are not stored because the RESULT_CACHE_MODE parameter is not set
to FORCE.
http://docs.oracle.com/database/121/TGDBA/tune_result_cache.htm#TGDBA631
C
I am thinking, if RESULT_CACHE_MAX_SIZE=0, then result cache is disable even though access Automatic Memory Management. But if the DBA doesn’t define RESULT_CACHE_MAX_SIZE, then the system can allocate the memory to the result cache up to 0.25%
C.
7 Memory Configuration and Use
7.3.4 Interpreting Shared Pool Statistics
7.3.4.1.3 Allocating Additional Memory to the Result Cache
By default, on database startup, Oracle allocates memory to the result cache in the shared pool.
The memory size allocated depends on the memory size of the shared pool and the memory management system.
When using the MEMORY_TARGET initialization parameter to specify the memory allocation,
Oracle allocates 0.25% of memory_target to the result cache.
When you set the size of the shared pool using the SGA_TARGET initialization parameter,
Oracle allocates 0.5% of sga_target to the result cache.
If you specify the size of the shared pool using the SHARED_POOL_SIZE initialization parameter,
then Oracle allocates 1% of the shared pool size to the result cache.
Oracle will not allocate more than 75% of the shared pool to the result cache.
https://docs.oracle.com/cd/B28359_01/server.111/b28274/memory.htm#i36899
15 Tuning the Result Cache
Configuring the Server Result Cache
The memory size allocated depends on the memory size of the shared pool and the selected memory management system:
Automatic shared memory management
If you are managing the size of the shared pool using the SGA_TARGET initialization parameter,
Oracle Database allocates 0.50% of the value of the SGA_TARGET parameter to the result cache.
Manual shared memory management
If you are managing the size of the shared pool using the SHARED_POOL_SIZE initialization parameter,
then Oracle Database allocates 1% of the shared pool size to the result cache.
docs.oracle.com/database/121/TGDBA/tune_result_cache.htm#TGDBA631