kafkajs: KafkaJSProtocolError: The broker received an out of order sequence number

Hi

I have a single producer:

const producer = kafka.producer({
  allowAutoTopicCreation: false,
  idempotent: true,
  maxInFlightRequests: 1
});

As you can see, I’m using the idempotent feature introduced in https://github.com/tulios/kafkajs/pull/203 I’m also forcing the maxInFlightRequests to 1

It works fine when my producer sends messages to the kafka server at a slow pace. By that I mean no requests are stored in the RequestQueue.

But during spike in activity, sometimes messages are automatically sent in batch. Kafka then returns the following error:

ERROR [ReplicaManager broker=0] Error processing append operation on partition TOPIC (kafka.server.ReplicaManager)
kafka_1                 | org.apache.kafka.common.errors.OutOfOrderSequenceException: Out of order sequence number for producerId 74: 158 (incoming seq. number), 156 (current end sequence number)

In this bug case, we have 156 → 158 jump, because 2 messages where sent in the batch.

According the kafka java code, it expects only a 1 unit jump so 156 → 157:

https://github.com/apache/kafka/blob/fecb977b257888e2022c1b1e04dd7bf03e18720c/core/src/main/scala/kafka/log/ProducerStateManager.scala#L241-L251

My current understanding/intuition, is that the firstSequence number should always be incremented by 1 and not by the number of messages present in the batch request.

Which roughly means that the updateSequence method of the EOSManager should not take an increment param but always increment by 1 only. https://github.com/tulios/kafkajs/blob/eae5ea42fc8ac035b0591a705b81829e3fedf8ad/src/producer/eosManager/index.js#L171-L197

I’m still quite noob on this codebase so my reasoning is probably flawed.

@ianwsperber , as you’re the main implementer of the eos code, what’s your take on this? Thanks a lot.