LogMiner的使用

LogMiner是用于Oracle日志挖掘的利器。
百科解释：

LogMiner 是Oracle公司从产品8i以后提供的一个实际非常有用的分析工具，使用该工具可以轻松获得Oracle 重做日志文件（归档日志文件）中的具体内容，LogMiner分析工具实际上是由一组PL/SQL包和一些动态视图组成，它作为Oracle数据库的一部分来发布，是oracle公司提供的一个完全免费的工具。

本文主要演示LogMiner的使用，直观展示LogMiner的作用。

环境：Oracle 11.2.0.4 RAC

• 1.查询当前日志组
• 2.业务用户插入操作
• 3.归档日志切换
• 4.业务用户删除操作
• 5.归档日志切换
• 6.业务用户更新操作
• 7.归档日志切换
• 8.确认需要分析的日志
• 9.备份归档日志
• 10.使用LogMiner分析

1.查询当前日志组

使用sys用户查询Oracle数据库的当前日志组:

--1.current log
SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIME   NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------ ------------ ------------
         1          1         29   52428800        512          2 YES INACTIVE               1547838 25-JUN-17         1547840 25-JUN-17
         2          1         30   52428800        512          2 NO  CURRENT                1567897 27-JUN-17      2.8147E+14 27-JUN-17
         3          2         25   52428800        512          2 NO  CURRENT                1567902 27-JUN-17      2.8147E+14
         4          2         24   52428800        512          2 YES INACTIVE               1567900 27-JUN-17         1567902 27-JUN-17

这里当前日志（current）是：
thread 1 sequence 30
thread 2 sequence 25

2.业务用户插入操作

模拟业务用户jingyu插入T2表数据：

--2.业务用户插入操作
sqlplus jingyu/jingyu@jyzhao
SQL> select count(1) from t2;

  COUNT(1)
----------
         0

SQL> insert into t2  select rownum, rownum, rownum, dbms_random.string('b',50)  from dual  connect by level <= 100000  order by dbms_random.random;
commit;

100000 rows created.

SQL> 
Commit complete.
SQL> select count(1) from t2;

  COUNT(1)
----------
    100000

3.归档日志切换

为了区分每个日志的不同操作，这里对数据库进行手工归档切换，模拟现实中实际的归档切换。

--3.模拟归档日志切换
SQL> alter system archive log current;

System altered.

SQL>  select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIME   NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------ ------------ ------------
         1          1         31   52428800        512          2 NO  CURRENT                1572517 27-JUN-17      2.8147E+14
         2          1         30   52428800        512          2 YES ACTIVE                 1567897 27-JUN-17         1572517 27-JUN-17
         3          2         25   52428800        512          2 YES ACTIVE                 1567902 27-JUN-17         1572521 27-JUN-17
         4          2         26   52428800        512          2 NO  CURRENT                1572521 27-JUN-17      2.8147E+14

4.业务用户删除操作

模拟业务用户jingyu删除T2表部分数据：

--4.业务用户删除操作

SQL> delete from t2 where id < 10000;

9999 rows deleted.

SQL> commit;

Commit complete.

SQL> select count(1) from t2;

  COUNT(1)
----------
     90001

5.归档日志切换

为了区分每个日志的不同操作，这里对数据库进行手工归档切换，模拟现实中实际的归档切换。

--5.模拟归档日志切换
SQL> alter system archive log current;

System altered.

SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIME   NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------ ------------ ------------
         1          1         31   52428800        512          2 YES ACTIVE                 1572517 27-JUN-17         1574293 27-JUN-17
         2          1         32   52428800        512          2 NO  CURRENT                1574293 27-JUN-17      2.8147E+14
         3          2         27   52428800        512          2 NO  CURRENT                1574296 27-JUN-17      2.8147E+14
         4          2         26   52428800        512          2 YES ACTIVE                 1572521 27-JUN-17         1574296 27-JUN-17

6.业务用户更新操作

模拟业务用户jingyu更新T2表部分数据：

--6.业务用户更新操作
SQL> update T2 SET contents = 'xxx' where id > 99998;

2 rows updated.

SQL> commit;

Commit complete.

7.归档日志切换

为了区分每个日志的不同操作，这里对数据库进行手工归档切换，模拟现实中实际的归档切换。

--7.模拟归档日志切换
SQL> alter system archive log current;

System altered.

SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIME   NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------ ------------ ------------
         1          1         33   52428800        512          2 NO  CURRENT                1575480 27-JUN-17      2.8147E+14
         2          1         32   52428800        512          2 YES ACTIVE                 1574293 27-JUN-17         1575480 27-JUN-17
         3          2         27   52428800        512          2 YES ACTIVE                 1574296 27-JUN-17         1575458 27-JUN-17
         4          2         28   52428800        512          2 NO  CURRENT                1575458 27-JUN-17      2.8147E+14

8.确认需要分析的日志

确认之后需要使用LogMiner分析的日志：

--8.确认需要分析的日志
thread# 1 sequence# 30
thread# 2 sequence# 25
这部分日志肯定是有记录插入操作

thread# 1 sequence# 31
thread# 2 sequence# 26
这部分日志肯定是有记录删除操作

thread# 1 sequence# 32
thread# 2 sequence# 27
这部分日志肯定是有记录更新操作

9.备份归档日志

将相关的归档都copy备份出来：

--9. 将相关的归档都copy备份出来
RUN {
allocate channel dev1 device type disk format '/tmp/backup/arc_%h_%e_%t';

backup as copy archivelog sequence 30 thread 1;
backup as copy archivelog sequence 31 thread 1;
backup as copy archivelog sequence 32 thread 1;
backup as copy archivelog sequence 25 thread 2;
backup as copy archivelog sequence 26 thread 2;
backup as copy archivelog sequence 27 thread 2;

release channel dev1;
}

备份出来的归档日志文件如下：

[oracle@jyrac1 backup]$ ls -lrth
total 17M
-rw-r----- 1 oracle asmadmin 2.3M Jun 27 21:50 arc_1_30_947800247
-rw-r----- 1 oracle asmadmin 591K Jun 27 21:50 arc_1_31_947800249
-rw-r----- 1 oracle asmadmin 143K Jun 27 21:50 arc_1_32_947800250
-rw-r----- 1 oracle asmadmin 9.5M Jun 27 21:50 arc_2_25_947800251
-rw-r----- 1 oracle asmadmin 3.6M Jun 27 21:50 arc_2_26_947800253
-rw-r----- 1 oracle asmadmin  77K Jun 27 21:50 arc_2_27_947800254

10.使用LogMiner分析

使用LogMiner分析归档日志：

--使用LogMiner分析归档日志
--应该有插入操作的日志
begin
	dbms_logmnr.add_logfile('/tmp/backup/arc_1_30_947800247');
	dbms_logmnr.add_logfile('/tmp/backup/arc_2_25_947800251');
	dbms_logmnr.start_logmnr(Options=>dbms_logmnr.dict_from_online_catalog);
end;
/

--应该有删除操作的日志
begin
   dbms_logmnr.add_logfile('/tmp/backup/arc_1_31_947800249');
   dbms_logmnr.add_logfile('/tmp/backup/arc_2_26_947800253');
   dbms_logmnr.start_logmnr(Options=>dbms_logmnr.dict_from_online_catalog);
end;
/

--应该有更新操作的日志
begin
   dbms_logmnr.add_logfile('/tmp/backup/arc_1_32_947800250');
   dbms_logmnr.add_logfile('/tmp/backup/arc_2_27_947800254');
   dbms_logmnr.start_logmnr(Options=>dbms_logmnr.dict_from_online_catalog);
end;
/

查询v$logmnr_contents

set lines 180 pages 500
col username format a8
col sql_redo format a50 
select username,scn,timestamp,sql_redo from v$logmnr_contents where table_name='T2'; 
select username,scn,timestamp,sql_redo from v$logmnr_contents where username='JINGYU';

select username,scn,timestamp,sql_redo from v$logmnr_contents where sql_redo like '%JINGYU%';

select username,scn,timestamp,sql_redo from v$logmnr_contents where sql_redo like 'insert%JINGYU%';
select username,scn,timestamp,sql_redo from v$logmnr_contents where sql_redo like 'delete%JINGYU%';
select username,scn,timestamp,sql_redo from v$logmnr_contents where sql_redo like 'update%JINGYU%';

实验发现，以username为条件无法查询到相关记录，最终确认username都是unknown而不是真正执行语句的业务用户jingyu。
而挖掘出的日志sql_redo这个字段是完整的SQL，可以采用like的方式查询，比如我分析更新操作的日志，就可以得到下面这样的结果：

SQL> --应该有更新操作的日志
SQL> begin
  2     dbms_logmnr.add_logfile('/tmp/backup/arc_1_32_947800250');
  3     dbms_logmnr.add_logfile('/tmp/backup/arc_2_27_947800254');
  4     dbms_logmnr.start_logmnr(Options=>dbms_logmnr.dict_from_online_catalog);
  5  end;
  6  /

PL/SQL procedure successfully completed.

SQL> select count(1) from v$logmnr_contents;

  COUNT(1)
----------
       388

SQL> select username,scn,timestamp,sql_redo from v$logmnr_contents where username='JINGYU';

no rows selected

SQL> select username,scn,timestamp,sql_redo from v$logmnr_contents where sql_redo like '%JINGYU%';

USERNAME                              SCN TIMESTAMP
------------------------------ ---------- ------------
SQL_REDO
--------------------------------------------------------------------------------
UNKNOWN                           1575420 27-JUN-17
update "JINGYU"."T2" set "CONTENTS" = 'xxx' where "CONTENTS" = 'YSWGNNLCLMYWPSLQ
ETVLGQJRKQIEAMOEYUFNRUQULVFRVPEDRV' and ROWID = 'AAAVWVAAGAAAAHnABj';

UNKNOWN                           1575420 27-JUN-17
update "JINGYU"."T2" set "CONTENTS" = 'xxx' where "CONTENTS" = 'WHCWFOZVLJWHFWLJ
DNVSMQTORGJFFXYADIOJZWJCDDOYXAOQJG' and ROWID = 'AAAVWVAAGAAAAOYAAE';


SQL> 

至此，LogMiner基本的操作实验已完成。

附：与LogMiner有关的一些操作命令参考：

conn / as sysdba
--安装LOGMINER
@$ORACLE_HOME/rdbms/admin/dbmslmd.sql;
@$ORACLE_HOME/rdbms/admin/dbmslm.sql;
@$ORACLE_HOME/rdbms/admin/dbmslms.sql;
@$ORACLE_HOME/rdbms/admin/prvtlm.plb;

--停止logmnr
exec dbms_logmnr.end_logmnr
   
--查询附加日志开启情况：
select supplemental_log_data_min, supplemental_log_data_pk, supplemental_log_data_ui from v$database;   

--开启附加日志
alter database add supplemental log data;

--取消补充日志
alter database drop supplemental log data (primary key) columns;
alter database drop supplemental log data (unique) columns;
alter database drop supplemental log data;

--最后一个即为新的归档
select name,dest_id,thread#,sequence# from v$archived_log; 

最后确认如果开启了附加日志，username就可以捕获到正确的值：

SQL> set lines 180
SQL> /

    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIME   NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------ ------------ ------------
         1          1         35   52428800        512          2 YES INACTIVE               1590589 27-JUN-17         1591935 27-JUN-17
         2          1         36   52428800        512          2 NO  CURRENT                1591935 27-JUN-17      2.8147E+14
         3          2         29   52428800        512          2 YES INACTIVE               1590594 27-JUN-17         1591938 27-JUN-17
         4          2         30   52428800        512          2 NO  CURRENT                1591938 27-JUN-17      2.8147E+14

1,36
2,30
SQL> update t2 set contents = 
  2  'aaa' where id = 44449;

1 row updated.

SQL> commit;

Commit complete.

RUN {
allocate channel dev1 device type disk format '/tmp/backup/arc_%h_%e_%t';

backup as copy archivelog sequence 36 thread 1;
backup as copy archivelog sequence 30 thread 2;

release channel dev1;
}

begin
	dbms_logmnr.add_logfile('/tmp/backup/arc_1_36_947808116');
	dbms_logmnr.add_logfile('/tmp/backup/arc_2_30_947808118');
	dbms_logmnr.start_logmnr(Options=>dbms_logmnr.dict_from_online_catalog);
end;
/

SQL> select username,scn,timestamp,sql_redo from v$logmnr_contents where username='JINGYU';

USERNAME                              SCN TIMESTAMP
------------------------------ ---------- ------------
SQL_REDO
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
JINGYU                            1593448 27-JUN-17
set transaction read write;

JINGYU                            1593448 27-JUN-17
update "JINGYU"."T2" set "CONTENTS" = 'aaa' where "CONTENTS" = 'WZTSQZWYOCNDFKSMNJQLOLFUBRDOHCBMKXBHAPJSHCMWBYZJVH' and ROWID = 'AAAVWVAAGAAAACLAAL';

JINGYU                            1593450 27-JUN-17
commit;

可以看到，开启了附加日志，就可以正常显示username的信息了。