Considerations for Cascading Topologies

This configuration can be used to perform data filtering and conversion if the character sets on all systems are identical. If character sets differ, conversions between character sets cannot be performed, and you must configure Replicat to perform the conversion and transformation on the target.

In Oracle GoldenGate environments earlier then 23ai, the parameters IGNOREAPPLOPS and GETREPLICATES were used to setup a cascaded replication environment. On the second system, you needed to configure the Extract group to capture Replicat activity and to ignore local business application activity.
With Oracle GoldenGate 23ai, the parameters IGNOREAPPLOPS and GETREPLICATES are desupported and you use tagging to streamline replication changes. In a default configuration, Replicat tags changes with a ‘00’ tag into the transitional database. The Extract process on the transitional database captures all DML changes, by default. However, for DDL operations, DDL tagging needs to be explicitly added if it needs to be replicated to the final target database. This is done by using the DDLOPTIONS INCLUDETAG 00parameter setting.

See the Cascading Script to learn about setting up replication and checking the replication statistics using the Admin Client commands and the REST API client.