The CDC Source connector is used to capture change log of existing databases like MySQL, MongoDB, PostgreSQL into Pulsar.
The CDC Source connector is built on top of Debezium and Canal. This connector stores all data into Pulsar Cluster in a persistent, replicated and partitioned way. This CDC Source are tested by using MySQL, and you could get more information regarding how it works at this debezium link or this canal link. Regarding how Debezium works, please reference to Debezium tutorial. Regarding how Canal works, please reference to Canal tutorial. It is recommended that you go through this tutorial first.