您好,登錄后才能下訂單哦!
如何進(jìn)行DAGScheduler源碼解讀,針對(duì)這個(gè)問(wèn)題,這篇文章詳細(xì)介紹了相對(duì)應(yīng)的分析和解答,希望可以幫助更多想解決這個(gè)問(wèn)題的小伙伴找到更簡(jiǎn)單易行的方法。
當(dāng)構(gòu)建完TaskScheduler之后,我們需要構(gòu)建DAGScheduler這個(gè)核心對(duì)象:
進(jìn)入其構(gòu)造函數(shù)中:
可以看出構(gòu)建DAGScheduler實(shí)例的時(shí)候需要把TaskScheduler實(shí)例對(duì)象作為參數(shù)傳入。
LiveListenerBus:
BlockManagerMaster:
通過(guò)閱讀代碼,我們可以發(fā)現(xiàn)DAGScheduler實(shí)例化的時(shí)候,調(diào)用了initializeEventProcessActor()方法
private def initializeEventProcessActor() { // blocking the thread until supervisor is started, which ensures eventProcessActor is // not null before any job is submitted // 阻塞當(dāng)前線(xiàn)程,等待supervisor啟動(dòng),這樣可以確保Job提交時(shí),eventProcessActor not null implicit val timeout = Timeout(30 seconds) val initEventActorReply = dagSchedulerActorSupervisor ? Props(new DAGSchedulerEventProcessActor(this)) eventProcessActor = Await.result(initEventActorReply, timeout.duration). asInstanceOf[ActorRef] } initializeEventProcessActor()
DAGSchedulerEventProcessActor:
private[scheduler] class DAGSchedulerEventProcessActor(dagScheduler: DAGScheduler) extends Actor with Logging { override def preStart() { // set DAGScheduler for taskScheduler to ensure eventProcessActor is always // valid when the messages arrive // 設(shè)置taskScheduler對(duì)DAGScheduler的引用句柄。在此處設(shè)置保證了Job提交時(shí)候 // eventProcessActor已經(jīng)準(zhǔn)備就緒 dagScheduler.taskScheduler.setDAGScheduler(dagScheduler) } /** * The main event loop of the DAG scheduler. */ def receive = { case JobSubmitted(jobId, rdd, func, partitions, allowLocal, callSite, listener, properties) => dagScheduler.handleJobSubmitted(jobId, rdd, func, partitions, allowLocal, callSite, listener, properties) case StageCancelled(stageId) => dagScheduler.handleStageCancellation(stageId) case JobCancelled(jobId) => dagScheduler.handleJobCancellation(jobId) case JobGroupCancelled(groupId) => dagScheduler.handleJobGroupCancelled(groupId) case AllJobsCancelled => dagScheduler.doCancelAllJobs() case ExecutorAdded(execId, host) => dagScheduler.handleExecutorAdded(execId, host) case ExecutorLost(execId) => dagScheduler.handleExecutorLost(execId, fetchFailed = false) case BeginEvent(task, taskInfo) => dagScheduler.handleBeginEvent(task, taskInfo) case GettingResultEvent(taskInfo) => dagScheduler.handleGetTaskResult(taskInfo) case completion @ CompletionEvent(task, reason, _, _, taskInfo, taskMetrics) => dagScheduler.handleTaskCompletion(completion) case TaskSetFailed(taskSet, reason) => dagScheduler.handleTaskSetFailed(taskSet, reason) case ResubmitFailedStages => dagScheduler.resubmitFailedStages() } override def postStop() { // Cancel any active jobs in postStop hook dagScheduler.cleanUpAfterSchedulerStop() } }
可以看出核心在于實(shí)例化eventProcessActor對(duì)象,eventProcessActor會(huì)負(fù)責(zé)接收和發(fā)送DAGScheduler的消息,是DAGScheduler的通信載體。
關(guān)于如何進(jìn)行DAGScheduler源碼解讀問(wèn)題的解答就分享到這里了,希望以上內(nèi)容可以對(duì)大家有一定的幫助,如果你還有很多疑惑沒(méi)有解開(kāi),可以關(guān)注億速云行業(yè)資訊頻道了解更多相關(guān)知識(shí)。
免責(zé)聲明:本站發(fā)布的內(nèi)容(圖片、視頻和文字)以原創(chuàng)、轉(zhuǎn)載和分享為主,文章觀點(diǎn)不代表本網(wǎng)站立場(chǎng),如果涉及侵權(quán)請(qǐng)聯(lián)系站長(zhǎng)郵箱:is@yisu.com進(jìn)行舉報(bào),并提供相關(guān)證據(jù),一經(jīng)查實(shí),將立刻刪除涉嫌侵權(quán)內(nèi)容。