【19C】logmnr参考

97 DBMS_LOGMNR

DBMS_LOGMNR包是LogMiner包的一组，它包含用于初始化LogMiner工具以及开始和结束LogMiner会话的子程序。
LogMiner包的CONTINUOUS_MINE功能已经过时了。它在Oracle数据库12c发行版2(12.2)中被弃用。没有替代功能。

This chapter contains the following topics:

Overview
Security Model
Constants
Views
Operational Notes
Summary of DBMS_LOGMNR Subprograms

97.1 DBMS_LOGMNR Overview

Oracle LogMiner是Oracle数据库的一部分，它允许您通过SQL接口在线查询和归档重做日志文件。DBMS_LOGMNR包提供了启动和停止LogMiner以及指定感兴趣的重做日志文件所需的大部分工具。
对用户数据或数据库字典所做的所有更改都记录在Oracle重做日志文件中，以便可以执行数据库恢复操作。您可以利用数据记录在重做日志文件完成其他任务，如:

Pinpointing when a logical corruption to a database, such as errors made at the application level, may have begun
Determining what actions you would have to take to perform fine-grained recovery at the transaction level.
Performance tuning and capacity planning through trend analysis.
Track any data manipulation language (DML) and data definition language (DDL) statements executed on the database, the order in which they were executed, and who executed them.

97.2 DBMS_LOGMNR Security Model

必须具有EXECUTE_CATALOG_ROLE角色才能使用DBMS_LOGMNR包。

97.3 DBMS_LOGMNR Constants

DBMS_LOGMNR包定义了几个枚举常量来指定参数值。枚举常量必须以包名作为前缀，例如DBMS_LOGMNR.NEW。

Note:

dbms_logmnr的continuous_mine选项。start_logmnr包被移植到Oracle数据库19c(19.1)中，不再可用。

下表描述了DBMS_LOGMNR包中ADD_LOGFILE选项标志的常量。

Table 97-1 Constants for ADD_LOGFILE Options Flag

Constant	Description
`NEW`	隐式调用DBMS_LOGMNR。END_LOGMNR过程结束当前LogMiner会话，然后创建一个新会话。新的会话启动一个新的要分析的重做日志文件列表，从您指定的重做日志文件开始。
`ADDFILE`	将指定的重做日志文件添加到要分析的重做日志文件列表中。添加重复文件的任何尝试都会引发异常(ORA-01289)。如果没有指定选项标志，这是默认值。

Table 97-2 describes the constants for the START_LOGMNR options flag in the DBMS_LOGMNR package.

Table 97-2 Constants for START_LOGMNR Options Flag

Constant	Description
`COMMITTED_DATA_ONLY`	如果设置，则返回与提交事务对应的DML语句。与提交事务对应的DML语句被分组在一起。事务按其提交顺序返回。被回滚或正在进行的事务被过滤掉，内部重做记录(与索引操作、管理等相关的记录)也是如此。如果没有设置此选项，则按照在重做日志中找到的顺序(按照SCN值的顺序)返回所有事务(已提交、回滚和正在进行的)的所有行。
`SKIP_CORRUPTION`	指示V$LOGMNR_CONTENTS视图上的选择操作，以跳过正在分析的重做日志文件中的任何错误，并继续处理。此选项仅在重做日志文件中的一个块(而不是重做日志文件的头)损坏时才有效。您应该检查V$LOGMNR_CONTENTS视图中的INFO列，以确定LogMiner跳过的损坏块。当跳过重做日志文件中的损坏时，操作列包含值腐蚀ted_blocks，而状态列包含值1343
`DDL_DICT_TRACKING`	如果使用的LogMiner字典是平面文件或在重做日志文件中，LogMiner会在DDL事件发生时更新它的内部字典。这可以确保为在构建LogMiner内部字典之后修改的对象维护正确的SQL_REDO和SQL_UNDO信息。LogMiner所连接的数据库必须是打开的。这个选项不能与DICT_FROM_ONLINE_CATALOG选项一起使用，而且当使用的LogMiner字典是在Oracle9i之前提取到平面文件的字典时，这个选项不能使用。
`DICT_FROM_ONLINE_CATALOG`	指示LogMiner使用当前的在线数据库字典，而不是包含在平面文件或正在分析的重做日志文件中的LogMiner字典。此选项不能与DDL_DICT_TRACKING选项一起使用。LogMiner所连接的数据库必须与生成重做日志文件的数据库相同。如果数据库中的表定义与重做日志文件中的表定义不匹配，则在V$LOGMNR_CONTENTS视图的状态列中预期会看到值为2。
`DICT_FROM_REDO_LOGS`	如果设置，LogMiner期望在指定的重做日志文件中找到LogMiner字典。重做日志文件使用DBMS_LOGMNR指定。ADD_LOGFILE过程或DBMS_LOGMNR。START_LOGMNR过程。
`NO_SQL_DELIMITER`	如果设置，则不会将SQL分隔符(分号)放在重新构建的SQL语句的末尾。这对于打开游标然后执行重构语句的应用程序很有帮助。
`NO_ROWID_IN_STMT`	如果设置，ROWID子句就不会包含在重新构建的SQL语句中。如果启用了补充日志记录，那么重做日志文件可能已经包含了修改行的逻辑唯一标识符。在使用此选项时，您必须确保在源数据库的适当级别上启用了补充日志记录，并且感兴趣的表中不存在重复的行。LogMiner不保证逻辑行标识符的唯一性。
`PRINT_PRETTY_SQL`	如果设置，LogMiner将格式化重新构建的SQL语句，以便阅读。这些重新构建的SQL语句是不可执行的。
`STRING_LITERALS_IN_STMT`	如果设置，SQL_REDO和SQL_UNDO将对数字、日期时间和间隔列类型使用文字。

要指定多个选项，请在它们之间使用加号(+)。例如:

CopyEXECUTE DBMS_LOGMNR.START_LOGMNR(OPTIONS => -DBMS_LOGMNR.DDL_DICT_TRACKING + DBMS_LOGMNR.DICT_FROM_REDO_LOGS);

97.4 DBMS_LOGMNR Views

DBMS_LOGMNR包使用下面列出的视图访问Oracle数据库实用程序视图中的Logminer操作信息。

97.5 DBMS_LOGMNR Operational Notes

LogMiner会话从对DBMS_LOGMNR的调用开始。ADD_LOGFILE或DBMS_LOGMNR。START_LOGMNR(如果您计划显式地指定日志文件，则使用前者;如果您计划使用连续挖掘，可以使用后者)。会话以对DBMS_LOGMNR.END_LOGMNR的调用结束。
在LogMiner会话中，您可以指定要分析的重做日志文件以及感兴趣的SCN或时间范围;然后可以对V$LOGMNR_CONTENTS视图发出SQL SELECT语句来检索感兴趣的数据。
必须在START_LOGMNR过程之前调用ADD_LOGFILE过程。

Note:

您必须在筛选之前添加日志文件。不再支持连续日志记录。如果没有添加与时间或您提供的SCN匹配的日志文件，则添加DBMS_LOGMNR。START_LOGMNR失败，出现ORA-01291错误:丢失日志文件。

97.6 Summary of DBMS_LOGMNR Subprograms

该表列出了DBMS_LOGMNR子程序并简要描述了它们。
在多租户容器数据库(CDB)中，必须从根调用一些子程序。可能还有其他不同之处。有关详细信息，请参阅各个子程序描述。

Table 97-3 DBMS_LOGMNR Package Subprograms

Subprogram	Description
ADD_LOGFILE Procedure	将重做日志文件添加到现有的或新创建的重做日志文件列表中，以便LogMiner处理，这样，如果创建了新的列表，就标志着LogMiner会话的开始
COLUMN_PRESENT Function	对于从V$LOGMNR_CONTENTS视图返回的任何行调用此函数，以确定对于该函数的column_name输入参数指定的列，是否存在撤销或重做列值
END_LOGMNR Procedure	完成一个LogMiner会话
MINE_VALUE Function	对于从V$LOGMNR_CONTENTS视图返回的任何行调用此函数，以检索由该函数的column_name输入参数指定的列的undo或redo列值
REMOVE_LOGFILE Procedure	从重做日志文件列表中删除一个重做日志文件，以便LogMiner处理
START_LOGMNR Procedure	初始化LogMiner实用程序并启动LogMiner(除非已经通过调用DBMS_LOGMNR.ADD_LOGFILE启动了会话)

97.6.1 ADD_LOGFILE Procedure

这个过程将一个文件添加到现有的或新创建的日志文件列表中，以便LogMiner处理。
注意:
dbms_logmnr的continuous_mine选项。start_logmnr包被移植到Oracle数据库19c(19.1)中，不再可用。
在CDB中，必须从根数据库调用ADD_LOGFILE过程。必须具有日志挖掘管理权限才能使用此过程。

Syntax

CopyDBMS_LOGMNR.ADD_LOGFILE ( LogFileName     IN VARCHAR2,options         IN BINARY_INTEGER default ADDFILE );

Parameters

Table 97-4 ADD_LOGFILE Procedure Parameters

Parameter Description

Parameter	Description
`LogFileName`	指定要添加到此会话期间要分析的重做日志文件列表中的重做日志文件的名称。
`options`	Does one of the following: Starts a new LogMiner session and a new list of redo log files for analysis (`DBMS_LOGMNR.NEW`) Adds a file to an existing list of redo log files for analysis (`DBMS_LOGMNR.ADDFILE`) See Table 97-1.

LogFileName

指定要添加到此会话期间要分析的重做日志文件列表中的重做日志文件的名称。

options

Does one of the following:

Starts a new LogMiner session and a new list of redo log files for analysis (DBMS_LOGMNR.NEW)
Adds a file to an existing list of redo log files for analysis (DBMS_LOGMNR.ADDFILE)

See Table 97-1.

Exceptions

Table 97-5 ADD_LOGFILE Procedure Exceptions

Exception	Description
`ORA-01284`	Specified file cannot be opened.
`ORA-01287`	Specified file is from a different database incarnation.
`ORA-01289`	Specified file has already been added to the list. Duplicate redo log files cannot be added.
`ORA-01290`	Specified file is not in the current list and therefore cannot be removed from the list.
`ORA-01324`	Specified file cannot be added to the list because there is a DB_ID mismatch.

Usage Notes

Before querying the V$LOGMNR_CONTENTS view, you must make a successful call to the DBMS_LOGMNR.START_LOGMNR procedure (within the current LogMiner session).
The LogMiner session must be set up with a list of redo log files to be analyzed. Use the ADD_LOGFILE procedure to specify the list of redo log files to analyze.
If you want to analyze more than one redo log file, you must call the ADD_LOGFILE procedure separately for each redo log file. The redo log files do not need to be registered in any particular order.
Both archived and online redo log files can be mined.
After you have added the first redo log file to the list, each additional redo log file that you add to the list must be associated with the same database and database RESETLOGS SCN as the first redo log file. (The database RESETLOGS SCN uniquely identifies each execution of an ALTER DATABASE OPEN RESETLOGS statement. When the online redo logs are reset, Oracle creates a new and unique incarnation of the database.)
To analyze the redo log files from a different database (or a database incarnation with a different database RESETLOGS SCN) than that with which the current list of redo log files is associated, use the END_LOGMNR procedure to end the current LogMiner session, and then build a new list using the ADD_LOGFILE procedure.
LogMiner matches redo log files by the log sequence number. Thus, two redo log files with different names but with the same log sequence number will return the ORA-01289 exception. For instance, the online counterpart of an archived redo log file has a different name from the archived redo log file, but attempting to register it with LogMiner after registering the archived counterpart will result in the ORA-01289 exception being returned.

97.6.2 COLUMN_PRESENT Function

这个函数被设计为与MINE_VALUE函数一起使用。
如果MINE_VALUE函数返回一个空值，它可以表示:
数据的重做或撤消部分中不存在指定的列。
指定的列已经存在，并且有一个空值。
要区分这两种情况，请使用COLUMN_PRESENT函数，如果该列出现在数据的重做或撤销部分，该函数将返回1。否则，它返回0。

Syntax

CopyDBMS_LOGMNR.COLUMN_PRESENT (sql_redo_undo      IN  RAW,column_name        IN  VARCHAR2 default '') RETURN NUMBER;

Parameters

Table 97-6 COLUMN_PRESENT Function Parameters

Parameter Description

Parameter	Description
`sql_redo_undo`	Specifies either the `REDO_VALUE` or the `UNDO_VALUE` column in the `V$LOGMNR_CONTENTS` view from which to extract data values. See the Usage Notes for more information.
`column_name`	Specifies the fully qualified name (`schema.table.column`) of the column for which this function will return information. In a CDB, the column name is specified as follows: `container_name:schema.table.column`

sql_redo_undo

Specifies either the REDO_VALUE or the UNDO_VALUE column in the V$LOGMNR_CONTENTS view from which to extract data values. See the Usage Notes for more information.

column_name

Specifies the fully qualified name (schema.table.column) of the column for which this function will return information.

In a CDB, the column name is specified as follows:

container_name:schema.table.column

Return Values

Table 97-7 describes the return values for the COLUMN_PRESENT function. The COLUMN_PRESENT function returns 1 if the self-describing record (the first parameter) contains the column specified in the second parameter. This can be used to determine the meaning of NULL values returned by the DBMS_LOGMNR.MINE_VALUE function.

Table 97-7 Return Values for COLUMN_PRESENT Function

Return	Description
`0`	Specified column is not present in this row of `V$LOGMNR_CONTENTS`.
`1`	Column is present in this row of `V$LOGMNR_CONTENTS`.

Exceptions

Table 97-8 COLUMN_PRESENT Function Exceptions

Exception	Description
`ORA-01323`	Currently, a LogMiner dictionary is not associated with the LogMiner session. You must specify a LogMiner dictionary for the LogMiner session.
`ORA-00904`	Value specified for the `column_name` parameter is not a fully qualified column name.

Usage Notes

To use the COLUMN_PRESENT function, you must have successfully started LogMiner.
The COLUMN_PRESENT function must be invoked in the context of a select operation on the V$LOGMNR_CONTENTS view.
The COLUMN_PRESENT function does not support LONG, LOB, ADT, or COLLECTION datatypes.
The value for the sql_redo_undo parameter depends on the operation performed and the data of interest:
- If an update operation was performed and you want to know what the value was prior to the update operation, specify UNDO_VALUE.
- If an update operation was performed and you want to know what the value is after the update operation, specify REDO_VALUE.
- If an insert operation was performed, typically you would specify REDO_VALUE (because the value of a column prior to an insert operation will always be NULL).
- If a delete operation was performed, typically you would specify UNDO_VALUE (because the value of a column after a delete operation will always be NULL).

97.6.3 END_LOGMNR Procedure

此过程完成一个LogMiner会话。由于此过程执行其他方式无法完成的清理操作，因此必须使用它来正确结束LogMiner会话。当您注销数据库会话或调用DBMS_LOGMNR时，将自动调用此过程。ADD_LOGFILE并指定新选项。

Syntax

CopyDBMS_LOGMNR.END_LOGMNR;

Exceptions

Table 97-9 END_LOGMNR Procedure Exception

Exception	Description
`ORA-01307`	No LogMiner session is currently active. The `END_LOGMNR` procedure was called without adding any log files or before the `START_LOGMNR` procedure was called

97.6.4 MINE_VALUE Function

此函数简化了基于列数据值的查询。
这个函数接受两个参数。第一个指定是挖掘数据的重做(REDO_VALUE)部分还是撤销(UNDO_VALUE)部分。第二个参数是一个字符串，它指定要挖掘的列的完全限定名。MINE_VALUE函数总是返回一个可以转换回原始数据类型的字符串。

Syntax

CopyDBMS_LOGMNR.MINE_VALUE (sql_redo_undo      IN  RAW,column_name        IN  VARCHAR2 default '') RETURN VARCHAR2;

Parameters

Table 97-10 MINE_VALUE Function Parameters

Parameter Description

Parameter	Description
`sql_redo_undo`	Specifies either the `REDO_VALUE` or the `UNDO_VALUE` column in the `V$LOGMNR_CONTENTS` view from which to extract data values. See the Usage Notes for more information.
`column_name`	Specifies the fully qualified name (`schema.table.column`) of the column for which this function will return information. In a CDB, the column name is specified as follows: `container_name:schema.table.column`

sql_redo_undo

Specifies either the REDO_VALUE or the UNDO_VALUE column in the V$LOGMNR_CONTENTS view from which to extract data values. See the Usage Notes for more information.

column_name

Specifies the fully qualified name (schema.table.column) of the column for which this function will return information.

In a CDB, the column name is specified as follows:

container_name:schema.table.column

Return Values

Table 97-11 Return Values for MINE_VALUE Function

Return	Description
`NULL`	The column is not contained within the self-describing record, or the column value is `NULL`. To distinguish between the two different null possibilities, use the `DBMS_LOGMNR.COLUMN_PRESENT` function.
`NON-NULL`	The column is contained within the self-describing record; the value is returned in string format.

Exceptions

Table 97-12 MINE_VALUE Function Exceptions

Exception	Description
`ORA-01323`	Invalid state. Currently, a LogMiner dictionary is not associated with the LogMiner session. You must specify a LogMiner dictionary for the LogMiner session.
`ORA-00904`	Invalid identifier. The value specified for the `column_name` parameter was not a fully qualified column name.

Usage Notes

To use the MINE_VALUE function, you must have successfully started LogMiner.
The MINE_VALUE function must be invoked in the context of a select operation from the V$LOGMNR_CONTENTS view.
The MINE_VALUE function does not support LONG, LOB, ADT, or COLLECTION datatypes.
The value for the sql_redo_undo parameter depends on the operation performed and the data of interest:
- If an update operation was performed and you want to know what the value was prior to the update operation, specify UNDO_VALUE.
- If an update operation was performed and you want to know what the value is after the update operation, specify REDO_VALUE.
- If an insert operation was performed, typically you would specify REDO_VALUE (because the value of a column prior to an insert operation will always be null).
- If a delete operation was performed, typically you would specify UNDO_VALUE (because the value of a column after a delete operation will always be null).
If the DBMS_LOGMNR.MINE_VALUE function is used to get an NCHAR value that includes characters not found in the database character set, then those characters are returned as the replacement character (for example, an inverted question mark) of the database character set.

97.6.5 REMOVE_LOGFILE Procedure

这个过程从现有的重做日志文件列表中删除重做日志文件，以便LogMiner处理。
在CDB中，必须从根数据库调用REMOVE_LOGFILE过程。必须具有日志挖掘管理权限才能使用此过程。

Syntax

CopyDBMS_LOGMNR.REMOVE_LOGFILE ( LogFileName     IN VARCHAR2);

Parameters

Table 97-13 REMOVE_LOGFILE Procedure Parameters

Parameter	Description
`LogFileName`	Specifies the name of the redo log file to be removed from the list of redo log files to be analyzed during this session.

Exceptions

Table 97-14 REMOVE_LOGFILE Procedure Exception

Exception	Description
`ORA-01290`	Cannot remove unlisted log file

Usage Notes

Before querying the V$LOGMNR_CONTENTS view, you must make a successful call to the DBMS_LOGMNR.START_LOGMNR procedure (within the current LogMiner session).
You can use this procedure to remove a redo log file from the list of redo log files for LogMiner to process if you know that redo log file does not contain any data of interest.
Multiple redo log files can be removed by calling this procedure repeatedly.
The redo log files do not need to be removed in any particular order.
To start a new list of redo log files for analysis, use the END_LOGMNR procedure to end the current LogMiner session, and then build a new list using the ADD_LOGFILE procedure.
Even if you remove all redo log files from the list, any subsequent calls you make to the ADD_LOGFILE procedure must match the database ID and RESETLOGS SCN of the removed redo log files. Therefore, to analyze the redo log files from a different database (or a database incarnation with a different database RESETLOGS SCN) than that with which the current list of redo log files is associated, use the END_LOGMNR procedure to end the current LogMiner session, and then build a new list using the ADD_LOGFILE procedure.

97.6.6 START_LOGMNR Procedure

这个过程通过加载LogMiner用来将内部模式对象标识符转换为名称的字典来启动LogMiner。
在CDB中，必须从根数据库调用START_LOGMNR过程。必须具有日志挖掘管理权限才能使用此过程。

Syntax

CopyDBMS_LOGMNR.START_LOGMNR ( startScn           IN NUMBER default 0,endScn             IN NUMBER default 0,startTime          IN DATE default '01-jan-1988',endTime            IN DATE default '31-dec-2110',DictFileName       IN VARCHAR2 default '',Options            IN BINARY_INTEGER default 0 );

Parameters

Table 97-15 START_LOGMNR Procedure Parameters

Parameter	Description
`startScn`	Directs LogMiner to return only redo records with an SCN greater than or equal to the `startScn` specified. This fails if there is no redo log file containing the specified `startScn` value. (You can query the `FILENAME`, `LOW_SCN,` and `NEXT_SCN` columns in the `V$LOGMNR_LOGS` view for each redo log file to determine the range of SCN values contained in each redo log file.)
`endScn`	Directs LogMiner to return only redo records with an SCN less than or equal to the `endScn` specified. If you specify an `endScn` value that is beyond the value in any redo log file, then LogMiner uses the greatest endScn value in the redo log file that contains the most recent changes. (You can query the `FILENAME,` `LOW_SCN,` and `NEXT_SCN` columns in the `V$LOGMNR_LOGS` view for each redo log file to determine the range of SCN values contained in each redo log file.)
`startTime`	Directs LogMiner to return only redo records with a timestamp greater than or equal to the `startTime` specified. This fails if there is no redo log file containing the specified `startTime` value. (You can query the `FILENAME`, `LOW_TIME,` and `HIGH_TIME` columns in the `V$LOGMNR_LOGS` view for each redo log file to determine the range of time covered in each redo log file.) This parameter is ignored if `startScn` is specified. See the Usage Notes for additional information.
`endTime`	Directs LogMiner to return only redo records with a timestamp less than or equal to the `endTime` specified. If you specify an `endTime` value that is beyond the value in any redo log file, then LogMiner will use the greatest `endTime` in the redo log file that contains the most recent changes. You can query the `FILENAME,` `LOW_TIME,` and `HIGH_TIME` columns in the V$LOGMNR_LOGS view for each redo log file to determine the range of time covered in each redo log file.) This parameter is ignored if `endScn` is specified. See the Usage Notes for additional information.
`DictFileName`	Specifies the flat file that contains the LogMiner dictionary. It is used to reconstruct `SQL_REDO` and `SQL_UNDO` columns in `V$LOGMNR_CONTENTS`, as well as to fully translate `SEG_NAME`, `SEG_OWNER`, `SEG_TYPE_NAME,` `TABLE_NAME,` and `TABLE_SPACE` columns. The fully qualified path name for the LogMiner dictionary file must be specified. (This file must have been created previously through the `DBMS_LOGMNR_D`.`BUILD` procedure.) You need to specify this parameter only if neither `DICT_FROM_REDO_LOGS` nor `DICT_FROM_ONLINE_CATALOG` is specified.
`options`	See Table 97-2.

Exceptions

Table 97-16 START_LOGMNR Procedure Exceptions

Exception	Description
`ORA-01280`	Internal error encountered.
`ORA-01281`	`startScn` or `endScn` parameter value is not a valid SCN, or `endScn` is less than `startScn`.
`ORA-01282`	value for the `startTime` parameter was greater than the value specified for the `endTime` parameter, or there was no redo log file that was compatible with the date range specified with the `startTime` and `endTime` parameters.
`ORA-01283`	Options parameter specified is invalid.
`ORA-01284`	LogMiner dictionary file specified in the `DictFileName` parameter has a full path length greater than 256 characters, or the file cannot be opened.
`ORA-01285`	Error reading specified file.
`ORA-01291`	Redo log files that are needed to satisfy the user's requested SCN or time range are missing.
`ORA-01292`	No log file has been specified for the current LogMiner session.
`ORA-01293`	Mounted database required for specified LogMiner options.
`ORA-01294`	Error occurred while processing information in the specified dictionary file, possible corruption.
`ORA-01295`	Specified LogMiner dictionary does not correspond to the database that produced the log files being analyzed.
`ORA-01296`	Character set mismatch between specified LogMiner dictionary and log files.
`ORA-01297`	Redo version mismatch between LogMiner dictionary and log files.
`ORA-01299`	Specified LogMiner dictionary corresponds to a different database incarnation.
`ORA-01300`	Writable database required for specified LogMiner options.

Usage Notes

Note:

The continuous_mine option for the dbms_logmnr.start_logmnr package is desupported in Oracle Database 19c (19.1), and is no longer available.

LogMiner can use a dictionary that you previously extracted to the redo log files or to a flat file, or you can specify that LogMiner use the online catalog if LogMiner is mining data from the source system.
After executing the START_LOGMNR procedure, you can query the following views:
- V$LOGMNR_CONTENTS - contains history of information in redo log files
- V$LOGMNR_DICTIONARY - contains current information about the LogMiner dictionary file extracted to a flat file
- V$LOGMNR_PARAMETERS - contains information about the LogMiner session
(You can query the V$LOGMNR_LOGS view after a redo log file list has been added to the list of files that LogMiner is to mine.)
Parameters and options are not persistent across calls to DBMS_LOGMNR.START_LOGMNR. You must specify all desired parameters and options (including SCN and time ranges) each time you call DBMS_LOGMNR.START_LOGMNR
Be aware that specifying redo log files using a timestamp is not precise.
Keep the following in mind regarding starting and ending times or SCN ranges:
- If you specify neither a startTime nor a startScn parameter, LogMiner will set the startScn parameter to use the lowest SCN value from the redo log file that contains the oldest changes.
- If you specify both time and SCN values, LogMiner uses the SCN value or values and ignores the time values.
- If you specify starting and ending time or SCN values and they are found in the LogMiner redo log file list, then LogMiner mines the logs indicated by those values.
- If you specify starting and ending times or SCN values that are not in the LogMiner redo log file list, and you specify DBMS_LOGMNR.START_LOGMNR, and you specify:
  - 0 for the startTime or startScn value, then the lowest SCN in the LogMiner redo log file list will be used as the startScn
  - A nonzero number for the startTime or startScn value, then an error is returned
  - 0 or a nonzero number for the endTime or endScn value, then the highest SCN in the LogMiner redo log file list will be used as the endScn
- If you specify starting and ending times or SCN values and they are not found in the LogMiner redo log file list, and you specify DBMS_LOGMNR.START_LOGMNR, and you specify:
  - 0 for the startTime or startScn value, then an error is returned.
  - A startTime or startScn value that is greater than any value in the database's archived redo log files, then LogMiner starts mining in the online redo log file. LogMiner will continue to process the online redo log file until it finds a change at, or beyond, the requested starting point before it returns rows from the V$LOGMNR_CONTENTS view.
  - An endTime or endScn parameter value that indicates a time or SCN in the future, then LogMiner includes the online redo log files when it mines. When you query the V$LOGMNR_CONTENTS view, rows will be returned from this view as changes are made to the database, and will not stop until LogMiner sees a change beyond the requested ending point.
  - 0 for the endTime or endScn parameter value, then LogMiner includes the online redo log files when it mines. When you query the V$LOGMNR_CONTENTS view, rows will be returned from this view as changes are made to the database, and will not stop until you enter CTL+C or you terminate the PL/SQL cursor.