Replicating Table Data to Master Sites

When you add a table to a master group, the Create Master Group Wizard presents the Copy Row Data option.

Allowing Oracle to Replicate Table Data

By default, when you add a table to a master group at the master definition site, Oracle replicates the data of the master definition site table to the table at all master sites. This option requires less administrative work but creates network traffic due to data copying.

• If the replicated table at other sites is not populated with data, then enable the Copy Row Data option.

• If the replicated table at other sites is already populated with data, then disable the Copy Row Data option, because enabling the option causes the data to be reloaded.

Manually Loading Table Data

Before adding a table to a group at the master definition site, you can precreate an identical table structure at each master site and then manually load identical data into each table replica. Later, when you add the object to the group at the master definition site, Oracle can use the existing table replicas and forego creating and replicating table data at each master site. This option is appropriate when you are configuring large tables and want to minimize the network traffic due to initial object creation and data replication. If you precreate the table and populate it with data, then disable the Copy Row Data option.

When you choose to populate a replicated table at a master site yourself, you are responsible for ensuring that the table data is consistent among all replicas in the system. For example, when manually populating replicated tables with data, do so before adding the table to its master group. Also, prevent applications from accessing the replicated table until the table is added to a master group and replication activity is resumed. Otherwise, the table might become inconsistent at the various master sites.

Offline Instantiation

If you are currently replicating a large amount of data and want to add a new site to the system, you should consider offline instantiation.