venkata91 commented on a change in pull request #33896:
URL: https://github.com/apache/spark/pull/33896#discussion_r741551702
##########
File path: core/src/main/scala/org/apache/spark/Dependency.scala
##########
@@ -131,7 +135,7 @@ class ShuffleDependency[K: ClassTag, V: ClassTag, C:
ClassTag](
def shuffleMergeId: Int = _shuffleMergeId
def setMergerLocs(mergerLocs: Seq[BlockManagerId]): Unit = {
- if (mergerLocs != null) {
+ if (mergerLocs != null && mergerLocs.nonEmpty) {
Review comment:
Most likely difference in the code from the internal and the OSS
version. Yes you're right, I don't think we need to check again here for
`nonEmpty`
##########
File path: core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
##########
@@ -1716,7 +1739,31 @@ private[spark] class DAGScheduler(
if (runningStages.contains(shuffleStage) &&
shuffleStage.pendingPartitions.isEmpty) {
if (!shuffleStage.shuffleDep.shuffleMergeFinalized &&
shuffleStage.shuffleDep.getMergerLocs.nonEmpty) {
- scheduleShuffleMergeFinalize(shuffleStage)
+ // Check if a finalize task has already been scheduled. This
is to prevent the
+ // following scenario: Stage A attempt 0 fails and gets
retried. Stage A attempt 1
+ // succeeded, triggering the scheduling of shuffle merge
finalization. However,
+ // tasks from Stage A attempt 0 might still be running and
sending task completion
+ // events to DAGScheduler. This check prevents multiple
attempts to schedule merge
+ // finalization get triggered due to this.
+ if (shuffleStage.shuffleDep.getFinalizeTask.isEmpty) {
+ // If total shuffle size is smaller than the threshold,
attempt to immediately
+ // schedule shuffle merge finalization and process map stage
completion.
+ val totalSize = Try(mapOutputTracker
+
.getStatistics(shuffleStage.shuffleDep).bytesByPartitionId.sum).getOrElse(0L)
Review comment:
This would fail when some of the tasks outputs are lost due to
node/executor loss which basically causes `MapOutputTracker.getStatistics`
throw exception. Thoughts?
##########
File path: core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
##########
@@ -1716,7 +1739,31 @@ private[spark] class DAGScheduler(
if (runningStages.contains(shuffleStage) &&
shuffleStage.pendingPartitions.isEmpty) {
if (!shuffleStage.shuffleDep.shuffleMergeFinalized &&
shuffleStage.shuffleDep.getMergerLocs.nonEmpty) {
- scheduleShuffleMergeFinalize(shuffleStage)
+ // Check if a finalize task has already been scheduled. This
is to prevent the
+ // following scenario: Stage A attempt 0 fails and gets
retried. Stage A attempt 1
+ // succeeded, triggering the scheduling of shuffle merge
finalization. However,
+ // tasks from Stage A attempt 0 might still be running and
sending task completion
+ // events to DAGScheduler. This check prevents multiple
attempts to schedule merge
+ // finalization get triggered due to this.
+ if (shuffleStage.shuffleDep.getFinalizeTask.isEmpty) {
+ // If total shuffle size is smaller than the threshold,
attempt to immediately
+ // schedule shuffle merge finalization and process map stage
completion.
+ val totalSize = Try(mapOutputTracker
+
.getStatistics(shuffleStage.shuffleDep).bytesByPartitionId.sum).getOrElse(0L)
Review comment:
Other usages of `getStatistics` are with in `mapStage.isAvailable` check
so its guaranteed to not throw exception. Unfortunately, that is not the case
here.
Do you mean we can avoid finalizing the shuffle for non-deterministic stage
in this case?
##########
File path: core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
##########
@@ -1716,7 +1739,31 @@ private[spark] class DAGScheduler(
if (runningStages.contains(shuffleStage) &&
shuffleStage.pendingPartitions.isEmpty) {
if (!shuffleStage.shuffleDep.shuffleMergeFinalized &&
shuffleStage.shuffleDep.getMergerLocs.nonEmpty) {
- scheduleShuffleMergeFinalize(shuffleStage)
+ // Check if a finalize task has already been scheduled. This
is to prevent the
+ // following scenario: Stage A attempt 0 fails and gets
retried. Stage A attempt 1
+ // succeeded, triggering the scheduling of shuffle merge
finalization. However,
+ // tasks from Stage A attempt 0 might still be running and
sending task completion
+ // events to DAGScheduler. This check prevents multiple
attempts to schedule merge
+ // finalization get triggered due to this.
+ if (shuffleStage.shuffleDep.getFinalizeTask.isEmpty) {
+ // If total shuffle size is smaller than the threshold,
attempt to immediately
+ // schedule shuffle merge finalization and process map stage
completion.
+ val totalSize = Try(mapOutputTracker
+
.getStatistics(shuffleStage.shuffleDep).bytesByPartitionId.sum).getOrElse(0L)
Review comment:
Other usages of `getStatistics` are with in `mapStage.isAvailable` check
so its guaranteed to not throw exception. Unfortunately, that is not the case
here.
@mridulm Do you mean we can avoid finalizing the shuffle for
non-deterministic stage in this case?
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