Use real-time extraction mode only if you run very few concurrent change data extractions. PowerExchange CDC creates an Oracle LogMiner session for each real-time extraction. Because LogMiner sessions are resource intensive, they can impact overall system performance. Instead, use continuous extraction mode. For continuous extraction mode, PowerExchange extracts change data from PowerExchange Logger log files.

If you use continuous extraction mode, minimize the size of the CDCT file. The CDCT file contains information about the PowerExchange Logger log files. PowerExchange reads the CDCT file each time the interval that is specified in the FILEWAIT parameter of the CAPX CAPI_CONNECTION statement elapses. If a CDCT file is large, PowerExchange read operations can result in a high level of I/O activity, increased use of system resources, and increased extraction latency. To manage the CDCT file size, use the COND_CDCT_RET_P statement in the pwxccl.cfg configuration file for the PowerExchange Logger for Linux, UNIX, and Windows.