Hi Andrea: Why not make your MyClass POJO? [1] If it is a POJO, then flink will use PojoTypeInfo and PojoSerializer that have a good implementation already.
[1] https://ci.apache.org/projects/flink/flink-docs-release-1.8/dev/types_serialization.html#rules-for-pojo-types Best, JingsongLee ------------------------------------------------------------------ From:Andrea Spina <andrea.sp...@radicalbit.io> Send Time:2019年7月4日(星期四) 14:37 To:user <user@flink.apache.org> Subject:Providing Custom Serializer for Generic Type Dear community, in my job, I run with a custom event type MyClass which is a sort of "generic event" that I handle all along my streaming flow both as an event (DataStream[MyClass]) and as a managed state. I see that Flink warns me about generic serialization of MyClass INFO [run-main-0] (TypeExtractor.java:1818) - class io.radicalbit.MyClass does not contain a setter for field io$radicalbit$MyClass$$schema INFO [run-main-0] (TypeExtractor.java:1857) - Class class io.radicalbit.MyClass cannot be used as a POJO type because not all fields are valid POJO fields, and must be processed as GenericType. Please read the Flink documentation on "Data Types & Serialization" for details of the effect on performance. INFO [run-main-0] (TypeExtractor.java:1818) - class io.radicalbit.MyClass does not contain a setter for field io$radicalbit$MyClass$schema So that I wanted to provide my custom serializer for MyClass, trying first to register the Java one to check if the system recognizes it so I followed [1] but it seems that it is not considered. I read then about [2] (the case is way akin to mine) and AFAIU I need to implement a custom TypeInformation and TypeSerializer for my class as suggested in [3] because Flink will ignore my registered serializer as long as it considers my type as generic. config.registerTypeWithKryoSerializer(classOf[MyClass], classOf[RadicalSerde]) My question finally is: Do I need to provide this custom classes? Is there any practical example for creating custom information like the above mentioned? I have had a quick preliminary look at it but seems that I need to provide a non-trivial amount of information to TypeInformation and TypeSerializer interfaces. Thank you for your excellent work and help. Cheers. [1] - https://ci.apache.org/projects/flink/flink-docs-stable/dev/custom_serializers.html [2] - http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Custom-Serializer-for-Avro-GenericRecord-td25433.html [3] - https://ci.apache.org/projects/flink/flink-docs-release-1.8/dev/types_serialization.html#defining-type-information-using-a-factory -- Andrea Spina Head of R&D @ Radicalbit Srl Via Giovanni Battista Pirelli 11, 20124, Milano - IT
