Question

我正在使用Kafka 0.10.2.1群集。我正在使用Kafka的offsetForTimes API来寻找特定的偏移量，并希望在达到结束时间戳时突破循环。

我的代码是这样的：

//package kafka.ex.test;

import java.util.*;



import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.OffsetAndTimestamp;
import org.apache.kafka.common.PartitionInfo;
import org.apache.kafka.common.TopicPartition;

public class ConsumerGroup {


   public static OffsetAndTimestamp fetchOffsetByTime( KafkaConsumer<Long, String> consumer , TopicPartition partition , long startTime){

      Map<TopicPartition, Long> query = new HashMap<>();
      query.put(
              partition,
              startTime);

      final Map<TopicPartition, OffsetAndTimestamp> offsetResult = consumer.offsetsForTimes(query);
      if( offsetResult == null || offsetResult.isEmpty() ) {
         System.out.println(" No Offset to Fetch ");
         System.out.println(" Offset Size "+offsetResult.size());



         return null;
      }
      final OffsetAndTimestamp offsetTimestamp = offsetResult.get(partition);
      if(offsetTimestamp == null ){
         System.out.println("No Offset Found for partition : "+partition.partition());
      }
      return offsetTimestamp;
   }

   public static KafkaConsumer<Long, String>  assignOffsetToConsumer( KafkaConsumer<Long, String> consumer, String topic , long startTime ){
      final List<PartitionInfo> partitionInfoList = consumer.partitionsFor(topic);
      System.out.println("Number of Partitions : "+partitionInfoList.size());
      final List<TopicPartition> topicPartitions = new ArrayList<>();
      for (PartitionInfo pInfo : partitionInfoList) {
         TopicPartition partition = new TopicPartition(topic, pInfo.partition());
         topicPartitions.add(partition);
      }
      consumer.assign(topicPartitions);
      for(TopicPartition partition : topicPartitions ){
         OffsetAndTimestamp offSetTs = fetchOffsetByTime(consumer, partition, startTime);


         if( offSetTs == null ){
            System.out.println("No Offset Found for partition : " + partition.partition());
            consumer.seekToEnd(Arrays.asList(partition));
         }else {
            System.out.println(" Offset Found for partition : " +offSetTs.offset()+" " +partition.partition());
            System.out.println("FETCH offset success"+
                    " Offset " + offSetTs.offset() +
                    " offSetTs " + offSetTs);
            consumer.seek(partition, offSetTs.offset());
         }
      }
      return consumer;
   }

   public static void main(String[] args) throws Exception {


      String topic = args[0].toString();
      String group = args[1].toString();

      long start_time_Stamp =  Long.parseLong( args[3].toString());
      String bootstrapServers = args[2].toString();
      long end_time_Stamp =  Long.parseLong( args[4].toString());
      Properties props = new Properties();
      boolean reachedEnd = false;

      props.put("bootstrap.servers", bootstrapServers);
      props.put("group.id", group);
      props.put("enable.auto.commit", "true");
      props.put("auto.commit.interval.ms", "1000");
      props.put("session.timeout.ms", "30000");
      props.put("key.deserializer",
         "org.apache.kafka.common.serialization.StringDeserializer");
      props.put("value.deserializer",
         "org.apache.kafka.common.serialization.StringDeserializer");

      KafkaConsumer<Long, String> consumer = new KafkaConsumer<Long, String>(props);
      assignOffsetToConsumer(consumer, topic, start_time_Stamp);


      System.out.println("Subscribed to topic " + topic);
      int i = 0;

      int arr[] = {0,0,0,0,0};
      while (true) {
         ConsumerRecords<Long, String> records = consumer.poll(6000);
         int count= 0;
         long lasttimestamp = 0;
         long lastOffset = 0;
            for (ConsumerRecord<Long, String> record : records) {

               count++;

               if(arr[record.partition()] == 0){
                  arr[record.partition()] =1;
               }


               if (record.timestamp() >= end_time_Stamp) {
                  reachedEnd = true;
                  break;
               }


               System.out.println("record=>"+" offset="
                       +record.offset()
                       + " timestamp="+record.timestamp()
                        + " :"+record);
               System.out.println("recordcount = "+count+" bitmap"+Arrays.toString(arr));

            }

         if (reachedEnd) break;
         if (records == null || records.isEmpty()) break; // dont wait for records
      }

   }



}

我遇到以下问题：

consumer.poll甚至在1000毫秒内失败。如果我使用1000毫秒，我必须在循环中轮询几次。我现在有一个非常大的价值。但是，已经寻求分区内的相关偏移量，如何可靠地设置轮询超时以便立即返回数据？
我的观察是，当返回数据时，并不总是来自所有分区。即使从所有分区返回数据，也不会返回所有记录。主题中的记录数量超过1000.但实际以循环方式获取和打印的记录数量较少（~200）。目前使用我的Kafka API有什么问题吗？

如何在开始和结束时间戳之间获得所有数据而不是过早地可靠地突破循环？

Answer 1

每次轮询提取的记录数量取决于您的消费者配置
当其中一个分区到达endtimestamp时，你正在打破循环，这不是你想要的。您应该在退出轮询循环之前检查是否已寻求结束所有分区
轮询是一个异步调用，每个节点都有获取请求和响应，因此根据代理响应时间，您可能会也可能不会获得轮询中的所有响应

kafka按时间戳，消费者循环

1 个答案: