Data Replication provides loopback avoidance to support bidirectional replication topologies that use one or more databases as both a source and target simultaneously.
For bidirectional replication, loopback avoidance prevents Data Replication from replicating changes back to the database from which they were originally captured.
Data Replication supports loopback avoidance by default. InitialSync and the Applier use transactions that have the default name of DbSyncTransaction to replicate data to a target. The Extractor uses this transaction name to distinguish the transactions that originally occurred on the database from the transactions that InitialSync and the Applier replicated. By default, the Extractor does not capture data from transactions that have the default transaction name of DbSyncTransaction. If you want the Extractor to capture change data from transactions that have this default name, set the SKIP_DEFAULT_TX command line parameter to N.
For cascade replication configurations, always set the SKIP_DEFAULT_TX command line parameter to N to disable loopback avoidance.
For DB2, Data Replication uses an application name instead of a transaction name to distinguish the changes that originally occurred on the database from the changes that InitialSync and the Applier processed. The default application name is also DbSyncTransaction.
In a complicated replication topology, you might need to use transactions that have a name other than the default transaction name to replicate changes to a target. In this case, use the TX_NAME command line parameter to specify the transaction name that you want InitialSync and the Applier to use. Also, for the Extractor that captures changes from the same database, specify the SKIP_TX command line parameter to skip the transactions that have the TX_NAME name that you specify for InitialSync and the Applier.