> For the complete documentation index, see [llms.txt](https://docs.rierino.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.rierino.com/devops/microservices/building-blocks/data-and-event-streams/cdc-feed.md).

# CDC Feed

Includes settings required for change data capture flows of a specific data table from [CDC systems](/devops/microservices/building-blocks/systems-integrations.md#cdc). Typically, name of this stream matches the source table name.

{% embed url="<https://www.youtube.com/watch?v=MCvRGhUhijg>" %}

While Samza runner CDC configurations are mainly done at system level, Spring runners allow the following configurations on each CDC stream:

| Setting                      | Definition                                                                           | Example     | Default |
| ---------------------------- | ------------------------------------------------------------------------------------ | ----------- | ------- |
| parameter.system             | Name of the system this stream is based on                                           | mongo\_cdc  | -       |
| parameter.offset.state       | Name of the state that stores CDC resume token                                       | cdc\_offset | -       |
| parameter.offset.partitioned | Whether offset should be stored per partition (i.e. if runner has multiple replicas) | true        | false   |
| parameter.offset.initial     | Initial offset to use, if missing from cdc state                                     | 100         | -       |
| parameter.asPulse            | Whether stream should produce pulses instead of CDC records                          | false       | true    |
| parameter.pollMs             | Milliseconds to wait if no new records are received from the stream                  | 5000        | 1000    |


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