1. Oracle GoldenGate Microservices Documentation
  2. Extract
  3. Oracle: DDL Replication
  4. Controlling the Propagation of DDL to Support Different Topologies
  5. Propagating DDL in Active-Active (Bidirectional) Configurations

Propagating DDL in Active-Active (Bidirectional) Configurations

Oracle GoldenGate supports active-active DDL replication between two systems. For an active-active bidirectional replication, the following must be configured in the Oracle GoldenGate processes:

  1. DDL that is performed by a business application on one system must be replicated to the other system to maintain synchronization. To satisfy this requirement, include the GETAPPLOPS option in the DDLOPTIONS statement in the Extract parameter files on both systems.

  2. DDL that is applied by Replicat on one system must be captured by the local Extract and sent back to the other system. To satisfy this requirement, use the GETREPLICATES option in the DDLOPTIONS statement in the Extract parameter files on both systems.

    Note:

    An internal Oracle GoldenGate token will cause the actual Replicat DDL statement itself to be ignored to prevent loopback. The purpose of propagating Replicat DDL back to the original system is so that the Replicat on that system can update its object metadata cache, in preparation to receive incoming DML, which will have the new metadata.

  3. Each Replicat must be configured to update its object metadata cache whenever the remote Extract sends over a captured Replicat DDL statement. To satisfy this requirement, use the UPDATEMETADATA option in the DDLOPTIONS statement in the Replicat parameter files on both systems.

The resultant DDLOPTIONS statements should look as follows:

Extract (primary and secondary)

DDLOPTIONS GETREPLICATES, GETAPPLOPS

Replicat (primary and secondary)

DDLOPTIONS UPDATEMETADATA

WARNING:

Before you allow new DDL or DML to be issued for the same object(s) as the original DDL, allow time for the original DDL to be replicated to the remote system and then captured again by the Extract on that system. This will ensure that the operations arrive in correct order to the Replicat on the original system, to prevent DML errors caused by metadata inconsistencies. See the following diagram for more information.

For more information, see Reference for Oracle GoldenGate.