Controlling the Propagation of DDL to Support Different Topologies

To support bidirectional and cascading replication configurations, it is important for Extract to be able to identify the DDL that is performed by Oracle GoldenGate and by other applications, such as the local business applications.

Depending on the configuration that you want to deploy, it might be appropriate to capture one or both of these sources of DDL on the local system.

Note:

Oracle GoldenGate DDL consists of ALTER TABLE statements performed by Extract to create log groups and the DDL that is performed by Replicat to replicate source DDL changes.

The following options of the DDLOPTIONS parameter control whether DDL on the local system is captured by Extract and then sent to a remote system, assuming Oracle GoldenGate DDL support is configured and enabled:

• The GETREPLICATES and IGNOREREPLICATES options control whether Extract captures or ignores the DDL that is generated by Oracle GoldenGate. The default is IGNOREREPLICATES, which does not propagate the DDL that is generated by Oracle GoldenGate. To identify the DDL operations that are performed by Oracle GoldenGate, the following comment is part of each Extract and Replicat DDL statement:

  /* GOLDENGATE_DDL_REPLICATION */

• The GETAPPLOPS and IGNOREAPPLOPS options control whether Extract captures or ignores the DDL that is generated by applications other than Oracle GoldenGate. The default is GETAPPLOPS, which propagates the DDL from local applications (other than Oracle GoldenGate).

The result of these default settings is that Extract ignores its own DDL and the DDL that is applied to the local database by a local Replicat, so that the DDL is not sent back to its source, and Extract captures all other DDL that is configured for replication. The following is the default DDLOPTIONS configuration.

DDLOPTIONS GETAPPLOPS, IGNOREREPLICATES

This behavior can be modified. See the following topics: