RAC禁用DRM特性

查看“_gc”開頭的隱藏參數值：

set linesize 333
col name for a35
col description for a66
col value for a30
SELECT   i.ksppinm name,  
   i.ksppdesc description,  
   CV.ksppstvl VALUE
FROM   sys.x$ksppi i, sys.x$ksppcv CV  
   WHERE   i.inst_id = USERENV ('Instance')  
   AND CV.inst_id = USERENV ('Instance')  
   AND i.indx = CV.indx  
   AND i.ksppinm LIKE '/_gc%' ESCAPE '/'  
ORDER BY   REPLACE (i.ksppinm, '_', '');  

--11g RAC關閉DRM特性

alter system set "_gc_policy_time"=0 scope=spfile sid='*';
alter system set "_gc_undo_affinity"=false scope=spfile sid='*';

--10g RAC關閉DRM特性

 alter system set "_gc_affinity_time"=0 scope=spfile sid='*';
 alter system set "_gc_undo_affinity"=FALSE scope=spfile sid='*';

參考老熊的文章，http://www.laoxiong.net/problem-caused-by-drm.html
10g RAC可以設置另外2個動態的隱含參數，來達到從”事實上“關閉DRM的目的：

 _gc_affinity_limit=250  
 _gc_affinity_minimum=10485760