PowerExchange Express CDC has its own log reader to get change data directly from the redo logs for real-time extraction processing. This architecture helps reduce the impact of log reading on the performance of the Oracle source system.

PowerExchange Express CDC capture components produce a change stream in which inserts, updates, and deletes are organized by transaction, and the transactions are arranged in their original commit order.

PowerExchange Express CDC can capture change data from most types of data source environments, including Oracle RACs that use Automatic Storage Management (ASM), Oracle Data Guard logical or physical standby databases, Oracle multitenant pluggable databases, and Oracle Exadata database machines.

Also, PowerExchange Express CDC can capture change data for cloud-based database instances deployed in an Amazon Elastic Compute Cloud (EC2) or Amazon Relational Database Service (RDS) for Oracle environment.

With PowerExchange Express CDC, use of the PowerExchange Logger for Linux, UNIX, and Windows is optional but strongly recommended. The PowerExchange Logger writes successful units of work (UOWs) in chronological order by end time to PowerExchange Logger log files. CDC sessions can then extract the change data from the PowerExchange Logger log files in either continuous extraction mode or batch extraction mode. Benefits of using the PowerExchange Logger include fewer database accesses, faster CDC restart, and no need for prolonged retention of the Oracle redo files for CDC.

To configure PowerExchange Express CDC, you must add some Oracle-specific statements to the DBMOVER configuration file and define the separate PowerExchange Express CDC configuration file, which has the default file name of pwxorad.cfg. Also, create capture registrations, configure PowerCenter CDC sessions, and configure restart processing, as normal. The restart token format for PowerExchange Express CDC for Oracle sources is different from that for any other data source type.

You must also perform some configuration tasks in Oracle. PowerExchange Express CDC requires the Oracle database to run in ARCHIVELOG mode with minimal global supplemental logging enabled.