Spring kafka idlebetweenpolls is always triggering partition rebalance - spring-boot

Question

I'm trying to use the idle between polls mentioned here to slow down the consumption rate, i also use the max.poll.interval.ms to double the idle between polls, but its always triggering partition rebalance, any idea what is the problem?
[Edit]
I have 5 hosts and i'm setting concurrency level to 1
[Edit 2]
I was setting the idle between polls to 5 min and max.poll.interval.ms to 10 min i also noticed this log "About to close the idle connection from 105 due to being idle for 540012 millis".
I decreased the idle between polls to 10 sec and the issue disappeared, any idea why?
private ConsumerFactory<String, GenericRecord> dlqConsumerFactory() {
Map<String, Object> configurationProperties = commonConfigs();
DlqConfiguration dlqConfiguration = kafkaProperties.getConsumer().getDlq();
final Integer idleBetweenPollInterval = dlqConfiguration.getIdleBetweenPollInterval()
.orElse(DLQ_POLL_INTERVAL);
final Integer maxPollInterval = idleBetweenPollInterval * 2; // two times the idleBetweenPoll, to prevent re-balancing
logger.info("Setting max poll interval to {} for DLQ", maxPollInterval);
overrideIfRequired(DQL_CONSUMER_CONFIGURATION, configurationProperties, ConsumerConfig.MAX_POLL_INTERVAL_MS_CONFIG, maxPollInterval);
dlqConfiguration.getMaxPollRecords().ifPresent(maxPollRecords ->
overrideIfRequired(DQL_CONSUMER_CONFIGURATION, configurationProperties, ConsumerConfig.MAX_POLL_RECORDS_CONFIG, maxPollRecords)
);
return new DefaultKafkaConsumerFactory<>(configurationProperties);
}

Answer 1

<time to process last polled records> + <idle between polls> must be less than max.poll.interval.ms.
EDIT
There is logic in the container to make sure we never exceed the max poll interval:
idleBetweenPolls = Math.min(idleBetweenPolls,
this.maxPollInterval - (System.currentTimeMillis() - this.lastPoll)
- 5000); // NOSONAR - less by five seconds to avoid race condition with rebalance
I can't reproduce the issue with this...
#SpringBootApplication
public class So63411124Application {
public static void main(String[] args) {
SpringApplication.run(So63411124Application.class, args);
}
#KafkaListener(id = "so63411124", topics = "so63411124")
public void listen(String in) {
System.out.println(in);
}
#Bean
public ApplicationRunner runner(ConcurrentKafkaListenerContainerFactory<?, ?> factory,
KafkaTemplate<String, String> template) {
factory.getContainerProperties().setIdleBetweenPolls(300000L);
return args -> {
while (true) {
template.send("so63411124", "foo");
Thread.sleep(295000);
}
};
}
#Bean
public NewTopic topic() {
return TopicBuilder.name("so63411124").partitions(1).replicas(1).build();
}
}
logging.level.org.springframework.kafka=debug
spring.kafka.consumer.auto-offset-reset=earliest
spring.kafka.consumer.properties.max.poll.interval.ms=600000
If you can provide a small example like this that exhibits the behavior you describe, I will take a look to see what's wrong.