oracle工具：logminer的简单使用

oracle工具：logminer的简单使用

我的环境：
[root@localhost ~]# uname -a
Linux localhost.localdomain 2.6.18-308.el5xen #1 SMP Fri Jan 27 17:59:00 EST 2012 i686 i686 i386 GNU/Linux
sys@ORCL> select * from v$version where rownum=1;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod

10g其实不需要生成dictionary文件了。只要直接把日志文件加载，然后分析即可。
1 产生数据库操作 www.2cto.com
[sql]
hr@ORCL> drop table t purge;

Table dropped.

hr@ORCL> create table logmnr_test (id number,name varchar2(20));

Table created.

hr@ORCL> insert into logmnr_test values(1,'think');

1 row created.

hr@ORCL> insert into logmnr_test values(2,'water');

1 row created.

hr@ORCL> commit;

Commit complete.

hr@ORCL> select sequence#,status from v$log;
www.2cto.com
SEQUENCE# STATUS
---------- ----------------
14 CURRENT
13 INACTIVE
12 INACTIVE
hr@ORCL> update logmnr_test set name='think_pad' where id=2;

1 row updated.

hr@ORCL> commit;

Commit complete.

hr@ORCL> alter system switch logfile;

System altered.

hr@ORCL> select sequence#,name from v$archived_log;

SEQUENCE#
----------
NAME
------------------------------------------------------------------------------------ ----------------
.............................
14
/u01/app/oracle/flash_recovery_area/ORCL/archivelog/2012_09_09/o1_mf_1_14_84qrj5co_.arc
www.2cto.com
2 为分析指定日志文件
[sql]
sys@ORCL> select db_name,thread_sqn,filename
2 from v$logmnr_logs;

no rows selected

sys@ORCL> exec DBMS_LOGMNR.ADD_LOGFILE('/u01/app/oracle/flash_recovery_area/ORCL/archivelog/2012_09_ 09/o1_mf_1_14_84qrj5co_.arc',dbms_logmnr.NEW);

PL/SQL procedure successfully completed.

若想接着分析更多的日志，把dbms_logmnr.NEW改成dbms_logmnr.addfile即可。

sys@ORCL> select db_name,thread_sqn,filename from v$logmnr_logs;

DB_NAME THREAD_SQN
-------- ----------
FILENAME
-------------------------------------------------------------------------------------
ORCL 14
/u01/app/oracle/flash_recovery_area/ORCL/archivelog/2012_09_09/o1_mf_1_14_84qrj5co_.arc www.2cto.com

3 启动logminer
[sql]
sys@ORCL> exec DBMS_LOGMNR.START_LOGMNR(OPTIONS => SYS.DBMS_LOGMNR.DICT_FROM_ONLINE_ CATALOG);

PL/SQL procedure successfully completed.

若是大数据量的分析，可以指定SCN或者时间的范围。

4 分析日志的内容
1)检查数据更改的细节
数据库里面的数据可能意想不到的原因或者错误而发生改变，在重做日志文件中可 以找到这些更改的细节，比如：谁做了这些改变？什么时候改的？怎么改的？
[sql]
select operation,timestamp,scn from v$logmnr_contents
where seg_name='LOGMNR_TEST' and
seg_owner='HR' and
seg_type_name='TABLE';

OPERATION TIMESTAMP SCN
-------------------------------- ------------------- ----------
DDL 2012/09/09 08:20:47 721905

select sql_redo,sql_undo from v$logmnr_contents
where seg_name='LOGMNR_TEST' and
seg_owner='HR' and
seg_type_name='TABLE';

SQL_REDO www.2cto.com
----------------------------------------------------------------------------------------
SQL_UNDO
----------------------------------------------------------------------------------------
create table logmnr_test (id number,name varchar2(20));

select username,session_info from v$logmnr_contents
where seg_name='LOGMNR_TEST' and
seg_owner='HR' and
seg_type_name='TABLE'

2)执行容量分析
如分析表产生DML的频数和频率
[sql]
select operation,timestamp,count(*) total from v$logmnr_contents
where seg_name='LOGMNR_TEST' and
seg_owner='HR' and
seg_type_name='TABLE'
group by operation,timestamp;

OPERATION TIMESTAMP TOTAL
-------------------------------- ------------------- ----------
DDL 2012/09/09 08:20:47 1

3)寻找DDL命令的细节
例如，使用logminer，可以找出删除表的具体时间和scn，便于media recovery。
[sql]
select seg_name,operation,scn,timestamp,count(*)
from v$logmnr_contents www.2cto.com
where operation='DELETE'
group by seg_name,operation,scn,timestamp
order by scn;

5 关闭logminer
如果需要进一步的分析，可将v$logmnr_contents内容保存下来
create table logmnr_contents as select * from v$logmnr_contents;
然后，执行关闭：
exec dbms_logmnr.end_logmnr;

附图：