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$version where rownum=1;
BANNER
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Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
10g其实不需要生成dictionary文件了。只要直接把日志文件加载，然后分析即可。
1 产生数据库操作
hr@ORCL> drop table t purge;Table dropped.hr@ORCL> create table logmnr_test (id number,name varchar2(20));Table created.hr@ORCL> insert into logmnr_test values(1,'think');1 row created.hr@ORCL> insert into logmnr_test values(2,'water');1 row created.hr@ORCL> commit; Commit complete.hr@ORCL> select sequence#,status from v$log; SEQUENCE# STATUS---------- ---------------- 14 CURRENT 13 INACTIVE 12 INACTIVEhr@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$archived_log; SEQUENCE#----------NAME----------------------------------------------------------------............................. 14/u01/app/oracle/flash_recovery_area/ORCL/archivelog/2012_09_09/o1_mf_1_14_84qrj5co_.arc
2 为分析指定日志文件
sys@ORCL> select db_name,thread_sqn,filename 2 from v$logmnr_logs;no rows selectedsys@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$logmnr_logs;DB_NAME THREAD_SQN-------- ----------FILENAME----------------------------------------------------------------ORCL 14/u01/app/oracle/flash_recovery_area/ORCL/archivelog/2012_09_09/o1_mf_1_14_84qrj5co_.arc
3 启动logminer
sys@ORCL> exec DBMS_LOGMNR.START_LOGMNR(OPTIONS => SYS.DBMS_LOGMNR.DICT_FROM_ONLINE_CATALOG);PL/SQL procedure successfully completed.若是大数据量的分析，可以指定SCN或者时间的范围。
4 分析日志的内容
1)检查数据更改的细节
数据库里面的数据可能意想不到的原因或者错误而发生改变，在重做日志文件中可以找到这些更改的细节，比如：谁做了这些改变？什么时候改的？怎么改的？
select operation,timestamp,scn from v$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 721905select sql_redo,sql_undo from v$logmnr_contents where seg_name='LOGMNR_TEST' and seg_owner='HR' and seg_type_name='TABLE'; SQL_REDO----------------------------------------------------------------SQL_UNDO----------------------------------------------------------------create table logmnr_test (id number,name varchar2(20));select username,session_info from v$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
select operation,timestamp,count(*) total from v$logmnr_contents where seg_name='LOGMNR_TEST' and seg_owner='HR' and seg_type_name='TABLE'group by operation,timestamp;OPERATION TIMESTAMP TOTAL-------------------------------- ------------------- ----------DDL 2012/09/09 08:20:47 1
3)寻找DDL命令的细节
例如，使用logminer，可以找出删除表的具体时间和scn，便于media recovery。
select seg_name,operation,scn,timestamp,count(*) from v$logmnr_contents 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：
