OCP 1Z0-053 Q115 -- 增大 DB_8K_CACHE_SIZE 大小

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Q115. 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
SGA_MAX_SIZE >= SGA_TARGET + DB_8K_CACHE_SIZE + LOG_BUFFER
1024 = 700 + 124 +200
要增大 DB_8K_CACHE_SIZE 的值，前提是 SGA_MAX_SIZE 有可用空间，否则需要增大 SGA_MAX_SIZE 的值。
本题中 SGA_MAX_SIZE 无可用空间，需相应增大 SGA_MAX_SIZE 的值。
SQL> alter system set sga_max_size=1040m scope=spfile; -- SGA_MAX_SIZE 16M ↑
SQL> shutdown immediate;
SQL> startup;
SQL> alter system set db_8k_cache_size=140m; -- DB_8K_CACHE_SIZE 16M ↑
SQL> show parameter sga_max_size;
SQL> show parameter db_8k_cache_size;