Introduction to CDC Replication for Oracle XStream

A high-level understanding of the Oracle XStream technology is helpful in planning for and configuring the CDC Replication Engine for Oracle XStream.

CDC Replication relies on Oracle XStream to be notified of changes to the database. Oracle XStream captures database changes through the Oracle XStream capture process and distributes data to CDC Replication through an XStream component called the outbound server. CDC Replication configures Oracle XStream components to include specific tables in scope that are associated with the subscriptions that consume data out of the outbound server. Oracle XStream supplies database changes to CDC Replication as Logical Change Records (LCRs) through the Oracle XStream API. A watermark is associated with each LCR that is supplied by the XStream API.

CDC Replication uses the Oracle JDBC driver to manage Oracle XStream components that are associated with the operations that are completed in Management Console or through the CDC Replication API. The names of most components that CDC Replication creates in Oracle follow the subscription name and a suffix pattern.

CDC Replication distributes LCRs adapted to a canonical format based on its table mapping assignments and subscriptions to target datastores. It also routinely notifies the Oracle XStream outbound server of the LCR watermark that has been applied to the target. This process permits the outbound server and in turn the Oracle XStream capture process to advance forward and release dependency on the database resources that contain the data that was replicated.

Review the Oracle XStream documentation in order to understand the requirement for the technology, what it supports, and its limitations.