Avro messages with schema

Question

So we are planning to use Avro for communication over a confluent kafka-based ecosystem. My current understanding of Avro is that each message carries its schema. If that is the case, we need schema registry just for resolving version updates?

I ask since carrying the schema with each message prevents the need for something like a schema registry to map a message id to a schema. Or am I missing something here?

Answer 1

When you run the Confluent Schema Registry, the Kafka messages published with the Confluent Avro Serdes library do not contain the avro schema. They only contain a numeric Schema id that is used by the consumers deserializer to fetch the Schema from the Confluent Schema Registry. These schemas are cached by the serializer and deserializer as a further performance optimization.