Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/18150#discussion_r121018254
--- Diff: core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
---
@@ -1383,19 +1394,43 @@ class DAGScheduler(
*/
private[scheduler] def handleExecutorLost(
execId: String,
- filesLost: Boolean,
- maybeEpoch: Option[Long] = None) {
+ workerLost: Boolean): Unit = {
+ // if the cluster manager explicitly tells us that the entire worker
was lost, then
+ // we know to unregister shuffle output. (Note that "worker"
specifically refers to the process
+ // from a Standalone cluster, where the shuffle service lives in the
Worker.)
+ val fileLost = workerLost ||
!env.blockManager.externalShuffleServiceEnabled
+ removeExecutorAndUnregisterOutputs(
+ execId = execId,
+ fileLost = fileLost,
+ hostToUnregisterOutputs = None,
+ maybeEpoch = None)
+ }
+
+ private def removeExecutorAndUnregisterOutputs(
+ execId: String,
+ fileLost: Boolean,
+ hostToUnregisterOutputs: Option[String],
+ maybeEpoch: Option[Long] = None): Unit = {
val currentEpoch = maybeEpoch.getOrElse(mapOutputTracker.getEpoch)
if (!failedEpoch.contains(execId) || failedEpoch(execId) <
currentEpoch) {
failedEpoch(execId) = currentEpoch
logInfo("Executor lost: %s (epoch %d)".format(execId, currentEpoch))
blockManagerMaster.removeExecutor(execId)
-
- if (filesLost || !env.blockManager.externalShuffleServiceEnabled) {
- logInfo("Shuffle files lost for executor: %s (epoch
%d)".format(execId, currentEpoch))
+ if (fileLost) {
+ hostToUnregisterOutputs match {
+ case Some(host) =>
+ logInfo("Shuffle files lost for host: %s (epoch
%d)".format(host, currentEpoch))
+ case None =>
+ logInfo("Shuffle files lost for executor: %s (epoch
%d)".format(execId, currentEpoch))
+ }
// TODO: This will be really slow if we keep accumulating shuffle
map stages
for ((shuffleId, stage) <- shuffleIdToMapStage) {
- stage.removeOutputsOnExecutor(execId)
+ hostToUnregisterOutputs match {
--- End diff --
@sitalkedia, that's a good point: the real gains here don't necessarily
come from the "multiple executors on a host" scenario; instead, it seems like
the key benefit is avoiding a bunch of followup stage failures to discover the
root of what needs to be recomputed. Your example in this comment is one of the
most clear problem statements of this that I've seen so far.
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