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updatestatebykey
怎样利用 Spark Streaming 和 Hadoop 实现近实时的会话连接
答:
}).reduceByKey((a, b) => { //transform to (ipAddress, (lowestStartTime, MaxFinishTime, sumOfCounter))(Math.min(a._1, b._1), Math.max(a._2, b._2), a._3 + b._3)}).
updateStateByKey
(updateStatbyOfSessions)这里有一个关于records如何在micro-batch中被reduce的例子:...
Storm,Spark,Flink对比
答:
spark是mirco-batch级别的计算,各种优化做的也很好,它的throughputs是最大的。但是需要提一下,有状态计算(如
updateStateByKey
算子)需要通过额外的rdd来维护状态,导致开销较大,对吞吐量影响也较大。storm的容错机制需要对每条data进行ack,因此容错开销对throughputs影响巨大,throughputs下降甚至可以达到...
通过线程池进行轮询
答:
public void
update
RefundInfo(RefundOrderPayDO refundOrderPayDO) { try { refundOrderPayRepository.updateRefundState(refundOrderPayDO); RefundOrderStateEnum refundOrderStateEnum =refundOrderInfoService.getRefundOrder
StateBy
Pay(refundOrderPayDO....
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