212.Note the following parameters settings in your database:
SGA_MAX_SIZE = 1024M
SGA_TARGET = 700M
DB_8K_CACHE_SIZE = 124M
LOG_BUFFER = 200M
You issued the following command to increase the value of DB_8K_CACHE_SIZE:
SQL> ALTER SYSTEM SET DB_8K_CACHE_SIZE=140M;
What would happen?
A. It will fail because DB_8K_CACHE_SIZE parameter cannot be changed dynamically
B. It will be successful only if the memory is available from the auto tuned components
C. It will fail because an increase in DB_8K_CACHE_SIZE cannot be accommodated within SGA_TARGET
D. It will fail because an increase in the DB_8K_CACHE_SIZE cannot be accommodated within SGA_MAX_SIZE
Answer: D
答案解析：
注意：这道题没有说明该数据库的标准块是8K。
其实在大多数我们的数据库标准块的大小为8K，所以就有了以下不能更新的问题，
但如果数据库的标准块不是8K，则是可以更改的。只要满足总的不能超过SGA_MAX_SIZE就可以了。
所以D应该算是对的。
13:56:20 sys@TEST1107> ALTER SYSTEM SET DB_8K_CACHE_SIZE=140m;
ALTER SYSTEM SET DB_8K_CACHE_SIZE=140m
*
ERROR at line 1:
ORA-32017: failure in updating SPFILE
ORA-00380: cannot specify db_8k_cache_size since 8K is the standard block size
[oracle@rtest ~]$ oerr ora 00380
00380, 00000, "cannot specify db_%sk_cache_size since %sK is the standard block size"
// *Cause: User specified the parameter db_nk_cache_size (where n is one of
// 2,4,8,16,32), while the standard block size for this database is
// equal to n Kbytes. This is illegal.
// *Action: Specify the standard block size cache using db_cache_size (DEFAULT
// pool) (and db_recycle_cache_size, db_keep_cache_size if additional
// buffer pools are required). Do NOT use the corresponding
// db_nk_cache_size parameter for the standard block size.
14:00:02 sys@TEST1107> ALTER SYSTEM SET db_cache_size=140m;
System altered.
因为总的SGA_MAX_SIZE为1024M,如果把DB_8K_CACHE_SIZE 设置为140M，则700M+200M+140M=1040M，超过了1024M，会报错。