Examine the memory-related parameters set in the SPFILE of an Oracle database:
memory_max_target—6G
memory_target=5G
pga_aggregate_target=500M
sga_max_size=0
sga_target=0
Which statement is true?
A.
Only SGA components are sized automaticallyB. Memory is dynamically re-allocated between the SGA and PGA as needed.
C.
The size of the PGA cannot grow automatically beyond 500 MB.
D.
The value of the MEMORY_TARGET parameter cannot be changed dynamically.
Explanation:
Where is the answer B?
The answers are:
A. Only SGA components are sized automatically-
B. Memory is dynamically re-allocated between the SGA and PGA as needed.
C. The size of the PGA cannot grow automatically beyond 500 MB.
D. The value of the MEMORY_TARGET parameter cannot be changed dynamically.
And the correct answer is C:
The size of the PGA cannot grow automatically beyond 500 MB
You’re wrong!
When Memory_target is set – AMM is activated! In that state, when PGA is set – that value (of PGA) acts as the minimum value Instance has to guarantee for PGA.
You can verify this by reading Memory management!
The correct option will be B.
When MEMORY_TARGET is set to a NON-ZERO value and if SGA_TARGET or PGA_TARGET is set to 0 or any positive number, then that number is taken as the minimum value. In that case it can definitely grow beyond 500 M.
B
B
—————————————————-
http://www.dba-oracle.com/t_amm_automatic_memory.htm
memory_target (starting in 11g): If memory_target is set, then AMM is enabled: If memory_target is set to non zero value and :
* sga_target and pga_aggregate_target are set to non-zero values, then these values will be considered minimum values.
* pga_aggregate_target is set and sga_target is not set. Both parameters will be auto-tuned. The sga_target will be initialized to a value of (memory_target-pga_aggregate_target).
I think it’s B. For reference 12c : http://docs.oracle.com/database/121/ADMIN/memory.htm#ADMIN11199
B
B is correct
If memory_target is set, then AMM is enabled.
If memory_target is set to non zero value and pga_aggregate_target is set and sga_target is not set. Both parameters will be auto-tuned. The sga_target will be initialized to a value of (memory_target-pga_aggregate_target).
B
B
PGA_AGGREGATE_TARGET is a minimum value, NOT a maximum one.
If the memory_target is non zero. PGA + SGA = MEMORY_TARGET
B
http://docs.oracle.com/database/121/ADMIN/memory.htm#ADMIN11200
With MEMORY_TARGET set, the SGA_TARGET setting becomes the minimum size of the SGA and the PGA_AGGREGATE_TARGET setting becomes the minimum size of the instance PGA. By setting both of these to zero as shown, there are no minimums, and the SGA and instance PGA can grow as needed as long as their sum is less than or equal to the MEMORY_TARGET setting. The sizing of SQL work areas remains automatic.
You can omit the statements that set the SGA_TARGET and PGA_AGGREGATE_TARGET parameter values to zero and leave either or both of the values as positive numbers. In this case, the values act as minimum values for the sizes of the SGA or instance PGA.