Configuring the Start Point for the Extractor Task
Configuring the Start Point for the Extractor Task
You can specify a Start Point value for a source database or instance to configure the Extractor to start processing the logs that contain the changes from a particular point. The Start Point value that you specify overrides the default Start Point value that the Data Replication Console calculates when you save the configuration.
For Oracle sources, the logs are redo logs. For DB2 and Microsoft SQL Server sources, the logs are transaction logs.
For MySQL sources, the logs are binary log files.
For the Start Point to take effect for Microsoft SQL Server and Oracle sources, ensure the
extract.process_old_logs
runtime parameter is set to 0.
On the
Map Tables
tab, click
Configure Start Point
.
The
Configure Start Point
dialog box appears. The following image shows this dialog box for an Oracle database:
The following image shows the
Configure Start Point
dialog box for a MySQL source:
Under
Extractor start point
, select the row for which to override the default Start Point value.
If you want the Extractor to start processing the log from the current SCN
, log coordinates,
or LSN value, right-click the row and click
Get SCN from Source
,
Get Index and Position from Source,
or
Get LSN from Source
.
The current value appears in the
Start from SCN
,
Start from Index and Position,
or
Start from LSN
column.
To discard changes and fall back to the last saved SCN
, log coordinates,
or LSN, click the
Reset
button above the list box, or right-click the row and click
Reset
.
If you want the Extractor to start processing the log from a particular SCN
, log coordinates,
or LSN value, complete the following steps:
Select a row and click the
Edit
icon button.
The
Edit Extractor SCN
,
Edit Extractor Index and Position
,
or
Edit Extractor LSN
dialog box appears.
In the
System change number
,
Index and Position,
or
Log sequence number
field, enter the SCN
, log coordinates,
or LSN from which the Extractor will start reading the log.
If you enter -1 or 0, the Extractor starts reading the log from the default Start Point value.
Click
Set
.
The specified SCN
, log coordinate,
or LSN value appears in the
Start from SCN
,
Start from Index and Position,
or
Start from LSN
column.
For
Microsoft SQL Server
sources that have multiple databases listed under
Extractor start point
, repeat steps 2 through 4 for each mapped database.