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Oracle9i Supplied PL/SQL Packages and Types Refere
DBMS_LOGMNR
The DBMS_LOGMNR package contains procedures used to initialize the LogMiner tool and to begin and end a LogMiner session.
| See Also: Oracle Database Utilities for information about using LogMiner and DBMS_LOGMNR_D for information on the package subprograms that extract a LogMiner dictionary and re-create LogMiner tables in alternate tablespaces |
This chapter contains the following topics:
LogMiner allows you to make queries based on actual data values. For instance, you could issue a query to select all updates to the table scott.emp or all deletions performed by user scott. You could also perform a query to show all updates to scott.emp that increased sal more than a certain amount. Such data can be used to analyze system behavior and to perform auditing tasks.
The DBMS_LOGMNR package contains procedures used to initialize the LogMiner tool. You use these procedures to list the redo log files to be analyzed and to specify the SCN or time range of interest. After these procedures complete, the server is ready to process SQL SELECT statements against the V$LOGMNR_CONTENTS view.
The data in redo log files is especially important for recovery, because you can use it to pinpoint when a database became corrupted.You can then use this information to recover the database to the state just prior to corruption.
This chapter discusses the following topics:
- DBMS_LOGMNR Constants
- Extracting Data Values From Redo Log Files
- Example of Using DBMS_LOGMNR
- Summary of DBMS_LOGMNR Subprograms
DBMS_LOGMNR Constants
The following sections describe the constants for the DBMS_LOGMNR package.
Constants for ADD_LOGFILE Options Flag
Constants for START_LOGMNR Options Flag
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| Directs a |
If the dictionary in use is a flat file or in the redo log files, LogMiner ensures that its internal dictionary is updated if a DDL event oclearcase/" target="_blank" >ccurs. This ensures that correct This option cannot be used in conjunction with the | |
| This option is only valid if the If you use this option, be aware that because the dictionary has not been refreshed for subsequent select operations, you may get incompletely reconstructed |
| Directs LogMiner to use the current live database dictionary rather than a dictionary snapshot contained in a flat file or in a redo log file. This option cannot be used in conjunction with the |
| If set, LogMiner expects to find a dictionary in the redo log files that were specified with the |
Extracting Data Values From Redo Log Files
LogMiner data extraction from redo log files is performed using two mine functions: DBMS_LOGMNR.MINE_VALUE and DBMS_LOGMNR.COLUMN_PRESENT, described later in this chapter.
Example of Using DBMS_LOGMNR
The following example shows how to use the DBMS_LOGMNR procedures to add redo log files to a LogMiner session, how to start LogMiner, how to perform a select operation from V$LOGMNR_CONTENTS, and how to end a LogMiner session. For complete descriptions of the DBMS_LOGMNR procedures, see Summary of DBMS_LOGMNR Subprograms.
EXECUTE DBMS_LOGMNR.ADD_LOGFILE( LogFileName => '/oracle/logs/log1.f', Options => dbms_logmnr.NEW); EXECUTE DBMS_LOGMNR.ADD_LOGFILE( LogFileName => '/oracle/logs/log2.f', Options => dbms_logmnr.ADDFILE); EXECUTE DBMS_LOGMNR.START_LOGMNR( DictFileName =>'/oracle/dictionary.ora'); SELECT sql_redo FROM V$LOGMNR_CONTENTS EXECUTE DBMS_LOGMNR.END_LOGMNR();
Summary of DBMS_LOGMNR Subprograms
Table 24-1 describes the procedures in the DBMS_LOGMNR supplied package.
