导读网站优化seo培训:1建站知识如何Shrink Undo表空间,释放过度占用的空间seo网站排名优化软件营销型网站建设。

环境:OS:Red Hat Enterprise Linux AS release 4 (Nahant)DB:Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production 一台Oracle10gR2数据库报出如下错误:ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX

登陆检查，发现是SYSAUX表空间空间用尽,不能扩展,尝试手工扩展SYSAUX表空间: alter database datafile '+ORADG/danaly/datafile/sysaux.266.600173881' resize 800mTue Nov 29 23:31:38 2005ORA-1237 signalled during: alter database datafile '+ORADG/danaly/datafile/sysaux.266.600173881' resize 800m...

出现ORA-1237错误，提示空间不足。这时候我才认识到是磁盘空间可能被用完了.是谁"偷偷的"用了那么多空间呢(本来有几十个G的Free磁盘空间的)?检查数据库表空间占用空间情况:SQL> select tablespace_name,sum(bytes)/1024/1024/1024 GB  2  from dba_data_files group by tablespace_name  3  union all  4  select tablespace_name,sum(bytes)/1024/1024/1024 GB  5  from dba_temp_files group by tablespace_name order by GB;TABLESPACE_NAME                        GB------------------------------ ----------USERS                          .004882813UNDOTBS2                        .09765625SYSTEM                         .478515625SYSAUX                         .634765625WAPCM_TS_VISIT_DETAIL            .9765625HY_DS_DEFAULT                           1MINT_TS_DEFAULT                         1MMS_TS_DATA2                        1.375MMS_IDX_SJH                             2MMS_TS_DEFAULT                          2IVRCN_TS_DATA                           2TABLESPACE_NAME                        GB------------------------------ ----------MMS_TS_DATA1                            2CM_TS_DEFAULT                           5TEMP                           20.5498047UNDOTBS1                       27.158203115 rows selected.不幸的发现，UNDO表空间已经扩展至27G，而TEMP表空间也扩展至20G，这2个表空间加起来占用了47G的磁盘空间,导致了空间不足。显然曾经有大事务占用了大量的UNDO表空间和Temp表空间，Oracle的AUM(Auto Undo Management)从出生以来就经常出现只扩展,不收缩(shrink)的情况(通常我们可以设置足够的UNDO表空间大小,然后取消其自动扩展属性).现在我们可以采用如下步骤回收UNDO空间:1.确认文件SQL> select file_name,bytes/1024/1024 from dba_data_files  2  where tablespace_name like 'UNDOTBS1';FILE_NAME--------------------------------------------------------------------------------BYTES/1024/1024---------------+ORADG/danaly/datafile/undotbs1.265.600173875          278102.检查UNDO Segment状态SQL> select usn,xacts,rssize/1024/1024/1024,hwmsize/1024/1024/1024,shrinks  2  from v$rollstat order by rssize;       USN      XACTS RSSIZE/1024/1024/1024 HWMSIZE/1024/1024/1024    SHRINKS---------- ---------- --------------------- ---------------------- ----------         0          0            .000358582             .000358582          0         2          0            .071517944             .071517944          0         3          0             .13722229              .13722229          0         9        网seo优化趋势;  0            .236984253             .236984253          0        10          0            .625144958             .625144958          0         5          1            1.22946167             1.22946167          0         8          0            1.27175903             1.27175903          0         4          1            1.27895355             1.27895355          0         7          0            1.56770325             1.56770325          0         1          0            2.02474976             2.02474976          0         6          0             2.9671936              2.9671936          011 rows selected.3.创建新的UNDO表空间SQL> create undo tablespace undotbs2 ;（经测试，在9i环境下后面还要加上datafile '/opt/..../undotbs2.dbf' size 1024M）Tablespace created.4.切换UNDO表空间为新的UNDO表空间SQL> alter system set undo_tablespace=undotbs2 scope=both;System altered.创建了新的UNDO表空间以后，如果不知道系统使用的是pfile还是spfile文件，应使用参数both,会同时修改spfile文件，避免出现冲突。

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