Debezium generates CDC ( Envelope) records that are struct of values containing values before and af
ter change. Sink connectors usually are not able to work with a complex structure so a user use this SMT to extract after value and send it down unwrapped in Envelope.
The functionality is similar to ExtractField SMT but has a special semantics for handling delete events; when delete event is emitted by database then Debezium emits two messages: a delete message and a tombstone message that serves as a signal to Kafka compaction process.
The SMT by default drops the tombstone message created by Debezium and converts the delete message into a tombstone message that can be dropped, too, if required. @param the subtype of ConnectRecord on which this transformation will operate @author Jiri Pechanec