Down Streams Capture Configuration
The configuration of Down Streams capture
can be achieved with either of two broadly defined methods.
These methods are Implicit Log Assignment capture and Explicit
Log Assignment capture. The Implicit method is the more common
method because the explicit method involves more manual tasks.
Log assignment by SQL command is a cumbersome procedure.
As shown in Figure 8.2, one method is where
log files are assigned implicitly to the Capture process running
at Down Streams database, and the second one is to assign the
redo log files explicitly by using the command ALTER DATABASE
REGISTER LOGICAL LOGFILE. In the implicit method, the log
transport service must be configured to transfer the archived
log files to the Down Streams database. The explicit method
involves the transfer of the archived redo log files using the
FTP method or any other copy method.
Figure 8.2 Methods of Down Streams
Capture Configuration
In the case of the implicit method, the
Down Streams database may or may not use the database link to
the source. Depending on whether or not the database link is
used, certain additional steps may be required. These steps
include manual instantiation and running dbms_capture_adm.build
procedure at the source database in order to extract the data
dictionary at the source database to the redo log.
Creating a database link from the Down
Streams capture database to the source database is optional.
However, creating the database link to source database
simplifies the configuration and management of the Down Streams
database.
