SQL> select * from v$sga;
NAME VALUE
-------------------- ----------
Fixed Size 454316
Variable Size 109051904
Database Buffers 503316480
Redo Buffers 667648
i can views the sga allocated on v$sga ;
questions:
1. where to set redo buffers values ?? in oracle9i init.ora files , i can pool size ,cache size e.g. but can't read about redo and undo
2. does the undo data blocks(roll segment ) exsits in memory ? do oracle will allocated a memory areas for undo ??? if treat it as log buffer or data buffer as well ???
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Re: where to set redo buffers initialize parameter values [message #167798 is a reply to message #167051 ]
Mon, 17 April 2006 03:12 Go to previous message
lazycat
Messages: 39
Registered: November 2005
Member
select * from v$parameter where name like '%log_buffer'
alter system set log_buffer=1M;
2 in orale memory ,no space for undo
the undo segment is in the rollback segment in the datafile
the sga only have the cache of the newest data
最初由 caoliwei 发布
[B]SQL> select * from v$sga;
NAME VALUE
-------------------- ----------
Fixed Size 454316
Variable Size 109051904
Database Buffers 503316480
Redo Buffers 667648
i can views the sga allocated on v$sga ;
questions:
1. where to set redo buffers values ?? in oracle9i init.ora files , i can pool size ,cache size e.g. but can't read about redo and undo
2. does the undo data blocks(roll segment ) exsits in memory ? do oracle will allocated a memory areas for undo ??? if treat it as log buffer or data buffer as well ???
Report message to a moderator
Send a private message to this user
Re: where to set redo buffers initialize parameter values [message #167798 is a reply to message #167051 ]
Mon, 17 April 2006 03:12 Go to previous message
lazycat
Messages: 39
Registered: November 2005
Member
select * from v$parameter where name like '%log_buffer'
alter system set log_buffer=1M;
2 in orale memory ,no space for undo
the undo segment is in the rollback segment in the datafile
the sga only have the cache of the newest data [/B]
1.当然是在pfile或者spfile里面，如果没有的话就添加一行
2.没有专用的undo buffer，undo blocks和db blocks同样存储在db buffer cache里面
