The task of the CDC agent is to read the database logs (or other change source), and to transform them into a format that is easy to process. The agent does not initiate any process on its own. It serves requests for change events from various clients. In the case of SQL-based CDC, the agentís client is the SQL-based Change Router.
The agent represents the changes as a stream of change events with a stream position (also known as contextí) pointing to the next change event to be retrieved.
On the first call in a specific application context, the agent uses the initial stream position that is specified in the agent configuration. The recommended setting for the initial stream position is Now which indicates that the first retrieval by an application will determine the time after which changes are captured.