关于undo表空间的几个问题

zjzbj

使用toad里面的dba菜单和select sum(bytes)/1048576 from dba_data_files where tablespace_name = 'UNDOTBS1'其实是一样的,监控方便点而已.

也是就是版主认为
dba_undo_extents统计出来的总使用空间+dba_free_space统计出来的UNDOTBS1的剩余空间=UNDOTBS1的空间大小至少不会相差太多,

而我这种统计出来相差悬殊10G的情况是不可能存在的,对不对



补充一下我的数据库是 自动UNDO管理

Yong Huang

> 也是就是版主认为
> dba_undo_extents统计出来的总使用空间+dba_free_space统计出来的UNDOTBS1的剩
> 余空间=UNDOTBS1的空间大小至少不会相差太多,

Yes. So in your case, dba_data_files where tablespace_name = 'UNDOTBS1' shows 37 GB. I'm not sure how to explain, and I can't reproduce it on my 10gR2 and 9iR2 databases.

There's a similar case at
http://www.dbasupport.com/forums/showthread.php?t=55241
with no explanation either.

Does this query
select sum(bytes)/1024/1024 from dba_extents where tablespace_name = 'UNDOTBS1'
show 3026 MB for you? (I got that by adding your 3 numbers in your query result in msg #3.)

Your database is not RAC. Correct?

Yong Huang

zjzbj

我的数据库是非rac,发生这种情况是在重建大表时候,有几个大表做alter table ... move ,大概有60G的数据量,不知道跟这个有没关系