i have several questions about db_cache_size ..
* system info
. oracle version 12.1.0.2
. total memory 128GB
* sga info (pfile setting value)
.sga_target = 0
.db_cache_size = 37GB
.sga_max_size=0
We have a plan to extend our memory. (128GB -> 256GB)
The reason is to increase db_cache_size. (About double, 37GB->74GB)
By the way, the current sga_target value is set to zero, and the sga_max_size is also set to zero.
(I saw the setting value through create pfile from spfile. )
Of course, when sga_max_size is inquired through v$, non-zero size is displayed.
The db_cache_size is also set to 37GB.
I wonder if it is okay to change db_cache_size simply through an alter command after the memory extension.
For example, ALTER SYSTEM SET Db_cache_size = 74GB SCOPE = SPFILE; and DB restart.
In addition, is there no need to change sga_max_size?
If the sga_target value is 0 then I want to make sure that there is no need to change the sga_max_size further.