oracle的结果集缓存
oracle 调整结果集缓存，只有3个参数。
RESULT_CACHE_MAX_SIZE=500M /* Megabytes
RESULT_CACHE_MAX_RESULT=20 /* Percentage
RESULT_CACHE_REMOTE_EXPIRATION=3600 /* Minutes
但是在 result_cache_mode 为force 的时候才会去保存所有的查询，在manual 的时候需要+HINT 来enable .
alter session set result_cache_mode=force;
show parameter result_cache
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
client_result_cache_lag big integer 3000
client_result_cache_size big integer 0
result_cache_max_result integer 5
result_cache_max_size big integer 5984K
result_cache_mode string MANUAL
result_cache_remote_expiration integer 0
查询下内存分配情况
SQL> SET SERVEROUTPUT ON
SQL> execute dbms_result_cache.memory_report
R e s u l t C a c h e M e m o r y R e p o r t
[Parameters]
Block Size = 1K bytes
Maximum Cache Size = 5984K bytes (5984 blocks)
Maximum Result Size = 299K bytes (299 blocks)
[Memory]
Total Memory = 174752 bytes [0.027% of the Shared Pool]
... Fixed Memory = 10696 bytes [0.002% of the Shared Pool]
... Dynamic Memory = 164056 bytes [0.026% of the Shared Pool]
....... Overhead = 131288 bytes
....... Cache Memory = 32K bytes (32 blocks)
........... Unused Memory = 30 blocks
........... Used Memory = 2 blocks
............... Dependencies = 1 blocks (1 count)
............... Results = 1 blocks
................... SQL = 1 blocks (1 count)
PL/SQL procedure successfully completed.
好像只有oracle 有这个东西，DB2 和mysql 都没有。
