Oracle Tips by Burleson

Oracle 10g LOGMINER

Oracle LogMiner is a powerful utility that queries the online and archived redo log files through the SQL interface. The redo log files record any change made to any table in the database. If the database is in archive mode (recommended) the Redo Files are archived into ‘archived redo files’. LogMiner can now mine (extract) information about these database changes and present them as SQL statements to undo or redo the change. It is a good aid when auditing or analyzing the historical activities or tasks of the database.

Before we go on to examine the new features introduced in Oracle Database 10g, let us recap the process involved in the LogMiner activity.

The LogMiner operations are conducted using the dbms_logmnr and dbms_logmnr_d PL/SQL package procedures. Data of interest is retrieved using the v$logmnr_contents view. The main steps are as follows:

• First, ensure that supplemental logging is on. LogMiner requires that you enable supplemental logging prior to starting the LogMiner session.
   

• Specify a LogMiner dictionary. Either use the dbms_logmnr_d.build procedure or specify the dictionary when you start the LogMiner process, depending on the type of dictionary you plan to use.
   

• Specify a list of redo and archive log files for analysis. For this, use the dbms_logmnr.add_logfiles procedure, or direct LogMiner to create a list of log files for analysis automatically when you start LogMiner.
   

• Then start the LogMiner session by using the start_logmnr procedure.
   

• Now, request the redo data of interest. For this, query the v$logmnr_contents view.
   

• End the LogMiner session by using the end_logmnr procedure of dbms_logmnr_d.

There are many new features within Database 10g that ease LogMiner administration and execution. Let us look at these features next.

Get the complete Oracle10g story:

The above text is an excerpt from "Oracle Database 10g New Features: Oracle10g Reference for Advanced Tuning and Administration", by Rampant TechPress.  Written by top Oracle experts, this book has a complete online code deport with ready to use scripts. 

To get the code instantly, click here:

http://rampant-books.com/book_2003_2_oracle10g.htm

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