I see a db where sga_max_size is set to 2634022912 bytes. db_cache_size is at
show sga deliveres this:
Total System Global Area 2634022912 bytes
Fixed Size 2098728 bytes
Variable Size 2332035544 bytes
Database Buffers 285212672 bytes = 272 MB
Redo Buffers 14675968 bytes
Questions:
How comes the db overshoots the defined value of 117440512 bytes, but is still not using all available memory for buffer cache?
Is the variable size waste/ unused?
I want to make the buffer cache as big as sensible. I prefer to unset db_cache_size and let the db make the decision. if I unset db_keep_cache_size and we generate load on the system (we actually haveI/O wait) will that memory be used right away in the cache, or will it take a while?
Is there somthing that we have to consider, like the double underscore parameters?