kafka 副本同步-如果follower fetch不到数据怎么办

最新推荐文章于 2024-07-21 15:48:25 发布

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最新推荐文章于 2024-07-21 15:48:25 发布

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分类专栏： kafka

本文链接：https://blog.youkuaiyun.com/m0_46449152/article/details/115098088

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1、follower发送fetch请求到leader，leader无数据更新时，加入时间轮（100ms）延迟调度给follower发送空响应（节约网络资源）
2、leader有数据更新时，会唤醒时间轮马上执行给follower发送空响应
follower接收到空响应后会继续向leader 发送fetch请求

KafkaApi.handle case ApiKeys.FETCH => handleFetchRequest(request)
replicaManager.fetchMessages
  def fetchMessages(timeout: Long,
                    replicaId: Int,
                    fetchMinBytes: Int,
                    fetchMaxBytes: Int,
                    hardMaxBytesLimit: Boolean,
                    fetchInfos: Seq[(TopicAndPartition, PartitionFetchInfo)],
                    quota: ReplicaQuota = UnboundedQuota,
                    responseCallback: Seq[(TopicAndPartition, FetchResponsePartitionData)] => Unit) {
   
    val isFromFollower = replicaId >= 0
    val fetchOnlyFromLeader: Boolean = replicaId != Request.DebuggingConsumerId
    val fetchOnlyCommitted: Boolean = ! Request.isValidBrokerId<