11G 结果集缓存限制

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结论是 结果缓存通过表的依赖而失效,也就是说相应表发生了数据变化那么就重新从表获取.相比时间 比普通45毫秒 高很多 达到945毫秒. 难道它不晓得从内存中获取吗? 还是觉得表数据有变化,直接从硬盘上读取才是真!

declare

B1 VARCHAR2(20);

B2 NUMBER;

ORG NUMBER(10);

S   TIMESTAMP;

E   TIMESTAMP;

R   TIMESTAMP;

begin

  B2:=12;

  B1:=668239581895;

FOR I IN 1..100 LOOP

S:=SYSTIMESTAMP;

SELECT  /*+ result_cache */ USE_IP into  IP

  FROM (SELECT A.USE_IP

               A.IP_TYPE

          FROM BACK_IP A

         WHEREA.IP_TYPE IN (3, 5, 9)

           ANDIP_LEGN = B2

           ANDA.START_IP <= B1

           ANDA.END_IP >= B1

         ORDER BYA.DISP_DATE DESC,

                  A.CREATE_TIME   DESC)

WHERE ROWNUM <= 1;

E:=SYSTIMESTAMP;

DBMS_OUTPUT.PUT_LINE(TO_CHAR(E-S));

DBMS_LOCK.SLEEP(10);

END LOOP;

END ;

测试结果 不很理想 波动性太大了.

+00000000000:00:00.090374000

+00000000000:00:00.102860000

+00000000000:00:00.000237000

+00000000000:00:00.000139000

+00000000000:00:00.000135000

+00000000000:00:00.000163000

+00000000000:00:00.000170000

+00000000000:00:00.000206000

+00000000000:00:00.000173000

+000000000 00:00:00.000171000

+00000000000:00:00.000170000

+00000000000:00:00.000139000

+00000000000:00:00.000267000

+00000000000:00:00.000171000

+00000000000:00:00.000160000

+00000000000:00:00.000180000

+00000000000:00:00.000161000

+00000000000:00:00.000183000

+00000000000:00:00.000182000

+00000000000:00:00.000139000

+00000000000:00:00.000147000

+00000000000:00:00.000160000

+00000000000:00:00.000212000

+00000000000:00:00.000353000

+00000000000:00:00.094454000

11G 结果集缓存限制

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原文地址：http://blog.csdn.net/zengmuansha/article/details/46011103