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目前有一个10g的数据库在检查时发现undo表空间异常庞大,undo表空间占了将近45G
1、首先查询当前undo表空间的使用情况,有文件使用已经达到32G
SQL> select file_name,bytes/1024/1024 MB,autoextensible from dba_data_files where tablespace_name like 'UNDOTBS1';
FILE_NAME MB AUT
---------------------------------------- ---------- ---
D:\ORADB\ORADATA\ORCL\UNDOTBS01.DBF 32767.9844 YES
D:\ORADB\ORADATA\ORCL\UNDOTBS02.DBF 8192 YES
D:\ORADB\ORADATA\ORCL\UNDOTBS03.DBF 4096 YES
2、查看当前undo的参数
SQL> show parameter undo;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS1
3、采取重建undo表空间的方法来,取消自动扩展
create undo tablespace undotbs2 datafile 'D:\ORADB\ORADATA\ORCL\UNDOTBS201.DBF' size 4G autoextend off;
alter tablespace undotbs2 add datafile 'D:\ORADB\ORADATA\ORCL\UNDOTBS202.DBF' size 4G autoextend off ;
alter tablespace undotbs2 add datafile 'D:\ORADB\ORADATA\ORCL\UNDOTBS203.DBF' size 4G autoextend off;
4、切换undo表空间
SQL>alter system set undo_tablespace=undotbs2 scope=both;
SQL> show parameter undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS2
5、查看当前的undo1 的回滚段状态
SQL> select segment_name,tablespace_name,status from dba_rollback_segs t where tablespace_name='UNDOTBS1' and status='OLINE';
SEGMENT_NAME TABLESPACE_NAME STATUS
------------------------------ ------------------------------ ----------------
_SYSSMU9$ UNDOTBS1 ONLINE
_SYSSMU10$ UNDOTBS1 ONLINE
6、由于上面的两个回滚段一直处于online状态,无法直接删除undotbs1表空间和数据文件回收空间,首先试着使用命令下线回滚段
SQL> ALTER ROLLBACK SEGMENT "_SYSSMU9$" OFFLINE;
Rollback segment altered.
7、查询回滚段状态,一直处于pengding offline状态
SQL> SELECT s.username, u.name ,r.status FROM v$transaction t, v$rollstat r, v$rollname u, v$session s WHERE s.taddr = t.addr AND t.xidusn = r.usn AND r.usn
= u.usn ORDER BY s.username;
USERNAME NAME STATUS
--------------------------- ------------------------------ ---------------
u01 _SYSSMU10$ PENDING OFFLINE
u02 _SYSSMU505$ ONLINE
u02 _SYSSMU501$ ONLINE
u02 _SYSSMU9$ PENDING OFFLINE
u02 _SYSSMU497$ ONLINE
u02 _SYSSMU506$ ONLINE
6 rows selected.
8、查找到相关的事务ID
SQL> SELECT s.sid,serial#, u.name ,r.status
2 FROM v$transaction t, v$rollstat r, v$rollname u, v$session s
3 WHERE s.taddr = t.addr AND t.xidusn = r.usn AND r.usn = u.usn and r.status='PENDING OFFLINE' ;
SID SERIAL# NAME STATUS
---------- ---------- ------------------------------ ---------------
3150 18393 _SYSSMU9$ PENDING OFFLINE
3175 9695 _SYSSMU10$ PENDING OFFLINE
9、根据上面的SID号查询该会话正在执行的操作
select sql_text from v$session a,v$sqltext_with_newlines b
where DECODE(a.sql_hash_value, 0, prev_hash_value, sql_hash_value)=b.hash_value
and a.sid=&sid order by piece;
10、结束该会话
alter system kill session '3150,18393';
alter system kill session '3175,9695';
ALTER ROLLBACK SEGMENT "_SYSSMU9$" OFFLINE;
ALTER ROLLBACK SEGMENT "_SYSSMU10$" OFFLINE;
11、验证当前undotbs1 是否全部offline
select * from dba_rollback_segs t where tablespace_name='UNDOTBS1' and status='ONLINE';
12、删除掉undotbs1
SQL> drop tablespace undotbs1 including contents and datafiles;
Tablespace dropped.
SQL> SELECT tablespace_name, status, SUM (bytes) / 1024 / 1024 "Bytes(M)"
2 FROM dba_undo_extents
3 GROUP BY tablespace_name, status;
TABLESPACE_NAME STATUS Bytes(M)
------------------------------ --------- ----------
UNDOTBS2 UNEXPIRED 29.8125
UNDOTBS2 EXPIRED 50.1875
UNDOTBS2 ACTIVE 3