Uncommitted event is not received in the next poll - offset

Question

I have a consumer with max.poll.records set to 1 and enable.auto.commit set to false for the manual offset control. However even when I am not calling commitSync, the subsequent poll is returning next event. Here are the details, I produced 4 events onto a topic, in consumer I am not committing for the third event I am skipping commitSync, I was expecting the third event to be returned in the next poll but fourth event has been returned. I am puzzled how evet 3 has been committed.
private static void pauseAndResume() {
int retryDelay = 5; // seconds
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
SimpleProducer.produce(4); //(produces Event1, Event2, Event3, Event4)
Properties properties = new Properties();
String topicName = "output-topic";
properties.put("bootstrap.servers", "localhost:29092");
properties.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
properties.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
properties.put("group.id", "test-group");
properties.put("max.poll.records", 1);
properties.put("enable.auto.commit", false);
KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<String, String>(properties);
List<String> topics = new ArrayList<String>();
topics.add(topicName);
kafkaConsumer.subscribe(topics);
Collection<TopicPartition> topicPartitions = new ArrayList<TopicPartition>();
PartitionInfo partitionInfo = kafkaConsumer.partitionsFor(topicName).get(0);
topicPartitions.add(new TopicPartition(partitionInfo.topic(), partitionInfo.partition()));
int eventsCount = 0;
try {
Date pausedAt = new Date();
while (true) {;
if (!kafkaConsumer.paused().isEmpty()) {
if ((new Date().getTime() - pausedAt.getTime()) / 1000 % 60 >= retryDelay) {
System.out.println("Resuming Consumer..." + sdf.format(new Date()));
kafkaConsumer.resume(topicPartitions);
}
}
ConsumerRecords<String, String> records = kafkaConsumer.poll(100);
for (ConsumerRecord<String, String> record : records) {
System.out.println(eventsCount + ":" + record.value());
if (record.value().equals("Event3")) {
System.out.println("consumer is pausing...... for about " + retryDelay + " seconds " + sdf.format(new Date()));
kafkaConsumer.pause(topicPartitions);
pausedAt = new Date();
break;
}else {
kafkaConsumer.commitSync();
}
}
}
} catch (Exception e) {
System.out.println(e.getMessage());
} finally {
kafkaConsumer.close();
}
}
The link KafkaConsumer<K,V> doesn't tell how to stop offset advancing ):
I think some smart internals detected indefinite poll of Event3 and returned Event4 instead
As per my research (google and Kafka forums) I expect the Event3 to replayed as it was not committed, but it's not happening, request someone to point me in the right direction.
Many Thanks

Answer 1

I figured out a workaround to explicitly seek on the topic partition
//In this use case we are consuming from single topic which has only one partition
kafkaConsumer.seek(topicPartitions.iterator().next(), record.offset());