[FLINK-9202] AvroSerializer should not be serializing the target Avro type class

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Not A Problem
• Component/s: API / Type Serialization System
• Assignee: Tzu-Li (Gordon) Tai
• Reporter: Tzu-Li (Gordon) Tai
• Created: 18/Apr/18 11:47
• Updated: 16/May/18 09:48
• Resolved: 14/May/18 07:48

Description

The AvroSerializer contains this field which is written when the serializer is written into savepoints:
https://github.com/apache/flink/blob/be7c89596a3b9cd8805a90aaf32336ec2759a1f7/flink-formats/flink-avro/src/main/java/org/apache/flink/formats/avro/typeutils/AvroSerializer.java#L78

This causes Avro schema evolution to not work properly, because Avro generated classes have non-fixed serialVersionUIDs. Once a new Avro class is generated with a new schema, that class can not be loaded on restore due to incompatible UIDs, and thus the serializer can not be successfully deserialized.

A possible solution would be to only write the classname, and dynamically load the class into a transient field.

Issue Links

• relates to: FLINK-9377 Remove writing serializers as part of the checkpoint meta information