[FLINK-11911] KafkaTopicPartition is not a valid POJO

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 1.8.0
• Component/s: Connectors / Kafka
• Labels: pull-request-available
• Assignee: Fokko Driesprong
• Reporter: Fokko Driesprong
• Created: 13/Mar/19 22:08
• Updated: 03/Jun/20 13:10
• Resolved: 03/Jun/20 13:09

Description

KafkaTopicPartition is not a POJO, and therefore it cannot be serialized efficiently. This is using the KafkaDeserializationSchema.

When enforcing POJO's:
```
java.lang.UnsupportedOperationException: Generic types have been disabled in the ExecutionConfig and type org.apache.flink.streaming.connectors.kafka.internals.KafkaTopicPartition is treated as a generic type.
at org.apache.flink.api.java.typeutils.GenericTypeInfo.createSerializer(GenericTypeInfo.java:86)
at org.apache.flink.api.java.typeutils.TupleTypeInfo.createSerializer(TupleTypeInfo.java:107)
at org.apache.flink.api.java.typeutils.TupleTypeInfo.createSerializer(TupleTypeInfo.java:52)
at org.apache.flink.api.java.typeutils.ListTypeInfo.createSerializer(ListTypeInfo.java:102)
at org.apache.flink.api.common.state.StateDescriptor.initializeSerializerUnlessSet(StateDescriptor.java:288)
at org.apache.flink.runtime.state.DefaultOperatorStateBackend.getListState(DefaultOperatorStateBackend.java:289)
at org.apache.flink.runtime.state.DefaultOperatorStateBackend.getUnionListState(DefaultOperatorStateBackend.java:219)
at org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.initializeState(FlinkKafkaConsumerBase.java:856)
at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.tryRestoreFunction(StreamingFunctionUtils.java:178)
at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.restoreFunctionState(StreamingFunctionUtils.java:160)
at org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.initializeState(AbstractUdfStreamOperator.java:96)
at org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:278)
at org.apache.flink.streaming.runtime.tasks.StreamTask.initializeState(StreamTask.java:738)
at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:289)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
at java.lang.Thread.run(Thread.java:748)
```

And in the logs:
```
2019-03-13 16:41:28,217 INFO org.apache.flink.api.java.typeutils.TypeExtractor - class org.apache.flink.streaming.connectors.kafka.internals.KafkaTopicPartition does not contain a setter for field topic
2019-03-13 16:41:28,221 INFO org.apache.flink.api.java.typeutils.TypeExtractor - Class class org.apache.flink.streaming.connectors.kafka.internals.KafkaTopicPartition 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.
```

Issue Links

• is related to: FLINK-15904 Make Kafka Consumer work with activated "disableGenericTypes()"
• relates to: FLINK-15904 Make Kafka Consumer work with activated "disableGenericTypes()"
• links to: GitHub Pull Request #7979