Using the Database Link
When a Down Streams Capture process uses a
database link connecting to the source database, it performs
certain administrative functions at the source database. They
are as follows:
-
When a Capture process is
created, it automatically runs the dbms_capture_adm.build
procedure at the source database in order to extract the data
dictionary at the source database to the redo log.
-
It prepares source database
objects for instantiation. It obtains the first_scn for
the Down Streams Capture process if the first_scn is not
specified during Capture process creation. The first_scn
is needed to create a Capture process.
-
If a Down Streams Capture
process does not use a database link, the above actions need to
be carried out manually.
Requirements
The Oracle10g release is required for
configuring Down Streams capture. In addition, 10g is required
on both the source and destination sides. This is because the
Down Streams feature is available only in the 10g version.
The operating system on the source and Down
Streams capture sites must be the same, but the operating system
releases need not be the same. In addition, the Down Streams
sites can use a different directory structure from the source
site.
Another requirement is that the hardware
architecture on the source and Down Streams capture sites need
to be the same but in a limited way. For example, a Down Streams
capture configuration with a source database on a 32-bit Solaris
must have a Down Streams database that is configured on a 32-bit
Solaris system. The other hardware components like the number of
CPUs, memory size, and storage configuration, can be different
between the source and Down Streams sites.
