LogMiner, first introduced in Oracle 8i, is used to analyze redo and archive logs. Here are the steps I preformed to test LogMiner functionality. The demonstration was executed on Win2K and Oracle8i.

  1. Add parameter to init.ora and restart database
    UTL_FILE_DIR = C:\oracle\admin\testlog
  2. Build dictionary
    Oracle8i Enterprise Edition Release 8.1.7.4.1 - 
Production JServer Release 8.1.7.4.1 - Production

MDINH@TEST> set serveroutput on
MDINH@TEST> BEGIN
  2    sys.dbms_logmnr_d.build
  3      ( DICTIONARY_FILENAME =>'dictionary.ora',
  4        DICTIONARY_LOCATION => 'C:\oracle\admin\testlog');
  5  END;
  6  /
LogMnr Dictionary Procedure started
LogMnr Dictionary File Opened
TABLE: OBJ$ recorded in LogMnr Dictionary File
TABLE: TAB$ recorded in LogMnr Dictionary File
TABLE: COL$ recorded in LogMnr Dictionary File
TABLE: SEG$ recorded in LogMnr Dictionary File
TABLE: UNDO$ recorded in LogMnr Dictionary File
TABLE: UGROUP$ recorded in LogMnr Dictionary File
TABLE: TS$ recorded in LogMnr Dictionary File
TABLE: CLU$ recorded in LogMnr Dictionary File
TABLE: IND$ recorded in LogMnr Dictionary File
TABLE: ICOL$ recorded in LogMnr Dictionary File
TABLE: LOB$ recorded in LogMnr Dictionary File
TABLE: USER$ recorded in LogMnr Dictionary File
TABLE: FILE$ recorded in LogMnr Dictionary File
TABLE: PARTOBJ$ recorded in LogMnr Dictionary File
TABLE: PARTCOL$ recorded in LogMnr Dictionary File
TABLE: TABPART$ recorded in LogMnr Dictionary File
TABLE:

    Requires Free Membership to View

    Login 

  1.  INDPART$ recorded in LogMnr Dictionary File
TABLE: SUBPARTCOL$ recorded in LogMnr Dictionary File
TABLE: TABSUBPART$ recorded in LogMnr Dictionary File
TABLE: INDSUBPART$ recorded in LogMnr Dictionary File
TABLE: TABCOMPART$ recorded in LogMnr Dictionary File
TABLE: INDCOMPART$ recorded in LogMnr Dictionary File
Procedure executed successfully - LogMnr Dictionary Created

PL/SQL procedure successfully completed.
  2. Add some data to table
    MDINH@TEST> select * from t1; 

no rows selected 

MDINH@TEST> insert into t1 values(1,'michael'); 

1 row created. 

MDINH@TEST> insert into t1 values(2,'erika'); 

1 row created. 

MDINH@TEST> commit; 

Commit complete.
  3. Take a look at the current redo log
    MDINH@TEST> BEGIN 
  2    sys.dbms_logmnr.add_logfile 
  3      ( LOGFILENAME => 'C:\ORADATA\TESTREDO03A.DBS', 
  4        OPTIONS => SYS.DBMS_LOGMNR.NEW); 
  5  END; 
  6  / 

PL/SQL procedure successfully completed. 

MDINH@TEST> BEGIN 
  2    sys.dbms_logmnr.start_logmnr 
  3       ( DICTFILENAME => 'C:\oracle\admin\testlog\dictionary.ora' ); 
  4  END; 
  5  
  6  / 

PL/SQL procedure successfully completed. 

MDINH@TEST> set linesize 500 
MDINH@TEST> select sql_undo 
  2  from v$logmnr_contents 
  3  where sql_undo like '%MDINH%T1%' 
  4  order by timestamp desc;
  4. This gives you the sql to undo the insert 
    SQL_UNDO 
----------------------------------------------------------------------------- 
delete from "MDINH"."T1" 
   where "T1_ID" = 2 and "NAME" = 'erika' and ROWID = 'AAAEwLAAEAAAAfCAAA'; 
delete from "MDINH"."T1" 
   where "T1_ID" = 1 and "NAME" = 'michael' and ROWID = 'AAAEwLAAEAAAAfCAAC'; 

MDINH@TEST> update t1 set name='erika dinh'; 

2 rows updated. 

MDINH@TEST> commit; 

Commit complete. 

MDINH@TEST> select sql_undo 
  2  from v$logmnr_contents 
  3  where sql_undo like '%MDINH%T1%' 
  4  order by timestamp desc;
    6. Here is the command to undo the update 
    SQL_UNDO 
--------------------------------------------------------------------------- 
update "MDINH"."T1" set "NAME" = 'erika' where ROWID = 'AAAEwLAAEAAAAfCAAA';
update "MDINH"."T1" set "NAME" = 'michael' where ROWID = 'AAAEwLAAEAAAAfCAAC'; 
delete from "MDINH"."T1" 
   where "T1_ID" = 2 and "NAME" = 'erika' and ROWID = 'AAAEwLAAEAAAAfCAAA'; 
delete from "MDINH"."T1" 
   where "T1_ID" = 1 and "NAME" = 'michael' and ROWID = 'AAAEwLAAEAAAAfCAAC'; 

MDINH@TEST> SELECT * FROM T1; 

     T1_ID NAME 
---------- ------------------------------ 
         2 erika dinh 
         1 erika dinh 

MDINH@TEST>

For More Information

  • Feedback: E-mail the editor with your thoughts about this tip.
  • More tips: Hundreds of free Oracle tips and scripts.
  • Tip contest: Have an Oracle tip to offer your fellow DBAs and developers? The best tips submitted will receive a cool prize -- submit your tip today!
  • Ask the Experts: Our SQL, database design, Oracle, SQL Server, DB2, metadata, and data warehousing gurus are waiting to answer your toughest questions.
  • Forums: Ask your technical Oracle questions--or help out your peers by answering them--in our active forums.
  • Best Web Links: Oracle tips, tutorials, and scripts from around the Web.

This was first published in April 2003

Join the conversationComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.

    Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.

    Back to top