您的位置：首页 > 其它

将经常使用的表放置在db_keep_cache_size中减少物理读

2014-02-20 14:26 363 查看

以下转自：http://www.itpub.net/thread-1809208-2-1.html 作者：zcs0237

一、设置KEEP池SYS@zcs11G> alter system set db_keep_cache_size=32m scope=spfile;shutdown immediate;show parameter db_keep--db_keep_cache_size big integer 32M二、查看数据库中已经有那些表被标记为热点表SYS@zcs11G> select '--',owner,segment_type,segment_name,buffer_pool from dba_segments where buffer_pool != 'DEFAULT';-- no rows selected

三、设置t11表的storage(buffer_pool keep)属性SYS@zcs11G> drop table t11 purge;create table t11 as select level id,lpad('z',4000,'z') name from dual connect by level <= 5000;alter table t11 storage(buffer_pool keep);select '--',bytes/1024/1024,'MB' from dba_segments where segment_name='T11';-- 40 MB四、查看是否在缓存keep中SYS@zcs11G> set pagesize 0set autotrace offcol segment_name for a12select '--',segment_name,buffer_pool from dba_segments where buffer_pool != 'DEFAULT';-- T11 KEEPSYS@zcs11G> set linesize 999select '--',a.status, count(*) from V$BH a, user_objects b where a.objd=b.object_id and object_name='T11' group by object_name, a.status;-- xcur 5001 T11中的数据已经全部放入KEEP池五、体会keep池的优势SYS@zcs11G> set autotrace trace statistics;select count(*) from t11;
Statistics---------------------------------------------------------- 140 recursive calls 0 db block gets 5090 consistent gets 5000 physical reads

SYS@zcs11G> select count(*) from t11;Statistics---------------------------------------------------------- 0 recursive calls 0 db block gets 5008 consistent gets 0 physical reads

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航