Kafka主题中丢失的消息 [英] Lost message from the Kafka Topic

问题描述

在 ProducerRecord 中尝试时间戳记;我发现了一些奇怪的东西.从生产者发送少量消息后，我运行了kafka-console-consumer.sh并验证了这些消息是否在主题中.我停下了制片人，等了一分钟.当我重新运行kafka-console-consumer.sh时，它没有显示我先前生成的消息.我还添加了producer.flush()和producer.close()，但结果仍然相同.

While trying timestamp in ProducerRecord; I found something weird. After sending few messages from the producer, I ran kafka-console-consumer.sh and verified that those messages are in the topic. I stopped the producer and waited for a minute. When I reran kafka-console-consumer.sh then it did not show the messages that I generated previously. I also added producer.flush() and producer.close() but the outcome was still the same.

现在，当我停止使用timestamp字段时，一切工作正常，这使我相信带有timestamp的消息有些挑剔.

Now, when I stopped using timestamp field then everything worked fine which makes me believe that there is something finicky about messages with timestamp.

我正在使用Kafka_2.11-2.0.0(于2018年7月30日发布)

I am using Kafka_2.11-2.0.0 (released on July 30, 2018)

以下是示例代码.

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.header.internal.RecordHeaders;
import org.apache.kafka.common.serialization.StringSerializer;
import java.util.Properties;
import static java.lang.Thread.sleep;
public class KafkaProducerSample{
    public static void main(String[] args){
        String kafkaHost="sample:port";
        String notificationTopic="test";

        Properties props = new Properties();
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, this.kafkaHost);
        props.put(ProducerConfig.ACKS_CONFIG, 1);
        props.put(ProducerConfig.RETRIES_CONFIG, Integer.MAX_VALUE);

        Producer<String, String> producer = new KafkaProducer(props, new StringSerialize(), new StringSerializer);

        RecordHeaders recordHeaders = new RecordHeader();
        ProducerRecord<String, String> record = new ProducerRecord(notificationTopic, null, 1574443515L, sampleKey, SampleValue);
        producer.send(record);
        sleep(1000);
    }
}

我按照以下方式运行控制台使用者

I run console consumer as following

$KAFKA_HOME/bin/kafka-console-consumer.sh --bootstrap.server KAFKA_HOST:PORT --topic test --from-beginning

#output after running producer
test


#output 5mins after shutting down producer

推荐答案

您仅异步发送一条记录，但没有确认或刷新缓冲区.

You are asynchronously sending only one record, but not ack-ing or flushing the buffer.

您将需要发送更多记录，

You will need to send more records,

或

producer.send(record).get();

或

producer.send(record);
producer.flush();

或(首选)，在您的main方法中执行Runtime.addShutdownHook()刷新并关闭生产者

or (preferred), do Runtime.addShutdownHook() in your main method to flush and close the producer

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