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[SPARK-53898][CORE] Shuffle cleanup should not clean MapOutputTrackerMaster.shuffleStatuses in local cluster #52606

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[SPARK-53898][CORE] Shuffle cleanup should not clean MapOutputTrackerMaster.shuffleStatuses in local cluster #52606

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5 changes: 4 additions & 1 deletion core/src/main/scala/org/apache/spark/MapOutputTracker.scala
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Expand Up @@ -942,7 +942,10 @@ private[spark] class MapOutputTrackerMaster(
}
}

/** Unregister shuffle data */
/**
* Unregister shuffle metadata. This currently should only be called through
* `ContextCleaner` when the shuffle is considered no longer referenced anywhere.
*/
def unregisterShuffle(shuffleId: Int): Unit = {
shuffleStatuses.remove(shuffleId).foreach { shuffleStatus =>
shuffleStatus.invalidateSerializedMapOutputStatusCache()
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11 changes: 9 additions & 2 deletions core/src/main/scala/org/apache/spark/storage/BlockManagerStorageEndpoint.scala
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Expand Up @@ -19,7 +19,7 @@ package org.apache.spark.storage

import scala.concurrent.{ExecutionContext, ExecutionContextExecutorService, Future}

import org.apache.spark.{MapOutputTracker, SparkEnv}
import org.apache.spark.{MapOutputTracker, MapOutputTrackerMaster, SparkEnv}
import org.apache.spark.internal.{Logging, MessageWithContext}
import org.apache.spark.internal.LogKeys.{BLOCK_ID, BROADCAST_ID, RDD_ID, SHUFFLE_ID}
import org.apache.spark.rpc.{IsolatedThreadSafeRpcEndpoint, RpcCallContext, RpcEnv}
Expand Down Expand Up @@ -57,7 +57,14 @@ class BlockManagerStorageEndpoint(

case RemoveShuffle(shuffleId) =>
doAsync[Boolean](log"removing shuffle ${MDC(SHUFFLE_ID, shuffleId)}", context) {
if (mapOutputTracker != null) {
if (mapOutputTracker != null && !mapOutputTracker.isInstanceOf[MapOutputTrackerMaster]) {
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Should this be in check be in unregistershuffle if we dont expect this to be called in master.
There can be someone else calling this same method on local mode in future?

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I was thinking about that. That way requires us to pass isLocal into MapOutputTrackerMaster, involves more changes. But I also agree it's safer.

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So with local mode, we can't clean up shuffle files only?

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I think shuffle cleanup still happens in local.
But the shuffle metadata cleanup only happens from ContextCleaner in driver.

// SPARK-53898: `MapOutputTrackerMaster.unregisterShuffle()` should only be called
// through `ContextCleaner` when the shuffle is considered no longer referenced anywhere.
// Otherwise, we might hit exceptions if there is any subsequent access (which still
// reference that shuffle) to that shuffle metadata in `MapOutputTrackerMaster`. E.g.,
// an ongoing subquery could access the same shuffle metadata which could have been
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I am not sure if we should mention this, since the ideal behavior would be to terminate any subqueries when the main query completes.

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There could be a race even if we terminating the subquery?

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The main query has ended already. The subqueries results are anyway not going to be used (and is also a waste of resource in allowing it to continue).

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@Ngone51 Ngone51 Oct 15, 2025 •
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I understand we should cancel the running subquery and we should do it. My point is the running subquery could still access MapOutputTrackerMaster even if we cancel it right after the main query ends due to the race between them. So I think it's fine to mention it here.

// cleaned up after the main query completes. Note this currently only happens in local
// cluster where both driver and executor use the `MapOutputTrackerMaster`.
mapOutputTracker.unregisterShuffle(shuffleId)
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so for non-local cluster, mapOutputTracker is at executors and unregisterShuffle only unregister the shuffle at executor side?

}
val shuffleManager = SparkEnv.get.shuffleManager
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5 changes: 5 additions & 0 deletions sql/core/src/test/scala/org/apache/spark/sql/execution/QueryExecutionSuite.scala
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Expand Up @@ -20,6 +20,7 @@ import scala.collection.mutable
import scala.io.Source
import scala.util.Try

import org.apache.spark.MapOutputTrackerMaster
import org.apache.spark.sql.{AnalysisException, ExtendedExplainGenerator, FastOperator, SaveMode}
import org.apache.spark.sql.catalyst.{QueryPlanningTracker, QueryPlanningTrackerCallback, TableIdentifier}
import org.apache.spark.sql.catalyst.analysis.{CurrentNamespace, UnresolvedFunction, UnresolvedRelation}
Expand Down Expand Up @@ -320,11 +321,15 @@ class QueryExecutionSuite extends SharedSparkSession {

private def cleanupShuffles(): Unit = {
val blockManager = spark.sparkContext.env.blockManager
val mapOutputTrackerMaster =
spark.sparkContext.env.mapOutputTracker.asInstanceOf[MapOutputTrackerMaster]
blockManager.diskBlockManager.getAllBlocks().foreach {
case ShuffleIndexBlockId(shuffleId, _, _) =>
spark.sparkContext.shuffleDriverComponents.removeShuffle(shuffleId, true)
case _ =>
}
// Shuffle cleanup should not clean up shuffle metadata on the driver
assert(mapOutputTrackerMaster.shuffleStatuses.nonEmpty)
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Tests fails this assert before the fix.

}

test("SPARK-53413: Cleanup shuffle dependencies for commands") {
Expand Down