自Oracle 11g起，無需設置UTL_FILE_DIR就可以使用LOGMNR對本地資料庫的日誌進行分析，以下是使用LOGMNR的DICT_FROM_ONLINE_CATALOG分析REDO和歸檔日誌的步驟 ...
自Oracle 11g起，無需設置UTL_FILE_DIR就可以使用LOGMNR對本地資料庫的日誌進行分析，以下是使用LOGMNR的DICT_FROM_ONLINE_CATALOG分析REDO和歸檔日誌的步驟
分析REDO日誌的實驗
- 創建測試表，並做DML操作。
SQL> create table t_test(id number,name varchar2(15));
Table created.
SQL> insert into t_test values(1,'stream');
1 row created.
SQL> insert into t_test values(2,'dbdream');
1 row created.
SQL> commit;
Commit complete.
SQL> update t_test set name='streamsong' where id=1;
1 row updated.
SQL> commit;
Commit complete.
SQL> delete from t_test;
2 rows deleted.
SQL> commit;
Commit complete.- 查看REDO日誌的路徑。
SQL> select member from v$logfile;
MEMBER
------------------------------------------------
/u01/app/oracle/oradata/stream/STREAM/redo03.log
/u01/app/oracle/oradata/stream/STREAM/redo02.log
/u01/app/oracle/oradata/stream/STREAM/redo01.log- 添加REDO日誌
第一個添加的日誌需指定NEW，如果確定要查詢的信息在指定的REDO日誌內，可以只添加那個REDO日誌，而不需要再添加其他
SQL> exec dbms_logmnr.add_logfile(logfilename=>'/u01/app/oracle/oradata/stream/STREAM/redo01.log',options=>dbms_logmnr.new);
PL/SQL procedure successfully completed.- 添加其他REDO日誌
不是第一個添加的日誌需指定ADDFILE。
SQL> exec dbms_logmnr.add_logfile(logfilename=>'/u01/app/oracle/oradata/stream/STREAM/redo02.log',options=>dbms_logmnr.addfile);
PL/SQL procedure successfully completed.
SQL> exec dbms_logmnr.add_logfile(logfilename=>'/u01/app/oracle/oradata/stream/STREAM/redo03.log',options=>dbms_logmnr.addfile);
PL/SQL procedure successfully completed.- 開始對添加的REDO進行分析
SQL> exec dbms_logmnr.start_logmnr(options=>dbms_logmnr.dict_from_online_catalog);
PL/SQL procedure successfully completed.- 查看LOGMNR分析後得到的信息
LOGMNR分析後的數據會存放在v$logmnr_contents視圖中，通過查詢v$logmnr_contents視圖就可以查詢到REDO日誌的信息。
SQL> select timestamp,sql_redo,sql_undo from v$logmnr_contents where username='SCOTT'and table_name='T_TEST';
TIMESTAMP SQL_REDO
--------- -----------------------------------------------------------
21-MAR-12 create table t_test(id number,name varchar2(15));
21-MAR-12 insert into "SCOTT"."T_TEST"("ID","NAME") values ('1','stream');
21-MAR-12 insert into "SCOTT"."T_TEST"("ID","NAME") values ('2','dbdream');
21-MAR-12 update "SCOTT"."T_TEST" set "NAME" = 'streamsong' where "NAME" ='stream' and ROWID = 'AAAR7fAAEAAAADXAAA';
21-MAR-12 delete from "SCOTT"."T_TEST" where "ID" = '1' and "NAME" = 'streamsong' and ROWID = 'AAAR7fAAEAAAADXAAA';
21-MAR-12 delete from "SCOTT"."T_TEST" where "ID" = '2' and "NAME" ='dbdream' and ROWID = 'AAAR7fAAEAAAADXAAB';SQL_REDO就是執行的SQL語句，SQL_UNDO是回滾操作的SQL語句，也就是執行SQL_UNDO的相關SQL，就可以回滾對應的操作。
註：LOGMNR是SESSION級的，以上實驗第3步到第6步需在同一個SESSION中進行，SESSION斷開連接後需重新執行，否則會報以下錯誤提示。
ORA-01306: dbms_logmnr.start_logmnr() must be invoked before selecting from v$logmnr_contents
- 結束LOGMNR操作
由於LOGMNR是會話級的，可以用直接退出或關閉當前的終端的方式來結束LOGMNR的操作，當然，正確的結束LOGMNR操作需使用下麵的命令。
SQL> exec dbms_logmnr.end_logmnr;
PL/SQL procedure successfully completed.分析歸檔日誌的實驗
分析歸檔日誌的操作和分析REDO的操作基本一樣，最重要的就是準確的找到需要查找的信息在哪些歸檔日誌內。既然是利用LOGMNR分析歸檔日誌，資料庫一定是在歸檔模式，要不哪來的歸檔日誌，可以通過如下命令查看資料庫是否啟用歸檔模式。
SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 15
Next log sequence to archive 17
Current log sequence 17可以看到當前資料庫已經開啟歸檔模式，歸檔地址是USE_DB_RECOVERY_FILE_DEST，USE_DB_RECOVERY_FILE_DEST的具體位置可以通過下麵的命令查看。
SQL> show parameter db_recove
NAME TYPE VALUE
--------------------------- ----------- -------------------------------
db_recovery_file_dest string /u01/app/oracle/flash_recovery_area
db_recovery_file_dest_size big integer 3852M如果數據據庫開啟閃回恢復區，閃回恢復區就是預設的歸檔地址，我個人建議使用這個空間存放歸檔日誌，因為從Oracle 11g開始當該空間的使用率達到80%的時候，系統會自動刪除已經備份過的歸檔文件，避免被撐爆。閃回恢復區的大小受db_recovery_file_dest_size大小的限制，是一個動態參數，可以隨時線上修改。
本實驗步驟如下：
- 切換日誌，使REDO日誌歸檔。
SQL> alter system switch logfile;
System altered.
SQL> /
System altered.
SQL> /
System altered.- 按照歸檔日誌的時間，找到存放需要分析信息的歸檔日誌。
[oracle@stream 2012_03_21]$ pwd
/u01/app/oracle/flash_recovery_area/STREAM/archivelog/2012_03_21
[oracle@stream 2012_03_21]$ ll
total 32196
-rw-r----- 1 oracle oinstall 26598912 Mar 21 10:55 o1_mf_1_12_7pljs9lb_.arc
-rw-r----- 1 oracle oinstall 6206976 Mar 21 14:05 o1_mf_1_13_7plvx3bc_.arc
-rw-r----- 1 oracle oinstall 100864 Mar 21 14:07 o1_mf_1_14_7plw0bgo_.arc
-rw-r----- 1 oracle oinstall 1024 Mar 21 14:07 o1_mf_1_15_7plw0d0q_.arc
-rw-r----- 1 oracle oinstall 2048 Mar 21 14:07 o1_mf_1_16_7plw0gc1_.arc- 將歸檔日誌添加到LOGMNR。
SQL> exec dbms_logmnr.add_logfile(logfilename=>'/u01/app/oracle/flash_recovery_area/STREAM/archivelog/2012_03_21/o1_mf_1_13_7plvx3bc_.arc',options=>dbms_logmnr.new);
PL/SQL procedure successfully completed.
SQL> exec dbms_logmnr.add_logfile(logfilename=>'/u01/app/oracle/flash_recovery_area/STREAM/archivelog/2012_03_21/o1_mf_1_14_7plw0bgo_.arc',options=>dbms_logmnr.addfile);
PL/SQL procedure successfully completed.- 開始分析。
SQL> exec dbms_logmnr.start_logmnr(options=>dbms_logmnr.dict_from_online_catalog);
PL/SQL procedure successfully completed.- 查看LOGMNR分析後的數據。
SQL> select timestamp,sql_redo from v$logmnr_contents where username='SCOTT' and table_name='T_TEST';
TIMESTAMP SQL_REDO
--------- -----------------------------------------------------------------
21-MAR-12 create table t_test(id number,name varchar2(15));
21-MAR-12 insert into "SCOTT"."T_TEST"("ID","NAME") values ('1','stream');
21-MAR-12 insert into "SCOTT"."T_TEST"("ID","NAME") values ('2','dbdream');
21-MAR-12 update "SCOTT"."T_TEST" set "NAME" = 'streamsong' where "NAME" =
'stream' and ROWID = 'AAAR7fAAEAAAADXAAA';
21-MAR-12 delete from "SCOTT"."T_TEST" where "ID" = '1' and "NAME" =
'streamsong' and ROWID = 'AAAR7fAAEAAAADXAAA';
21-MAR-12 delete from "SCOTT"."T_TEST" where "ID" = '2' and "NAME" =
'dbdream' and ROWID = 'AAAR7fAAEAAAADXAAB';
6 rows selected.- 結束LOGMNR操作。
SQL> exec dbms_logmnr.end_logmnr;
PL/SQL procedure successfully completed.
