Repository: spark
Updated Branches:
refs/heads/branch-1.5 37b6403cb -> 472f0dc34
[SPARK-9709] [SQL] Avoid starving unsafe operators that use sort
The issue is that a task may run multiple sorts, and the sorts run by the child
operator (i.e. parent RDD) may acquire all available memory such that other
sorts in the same task do not have enough to proceed. This manifests itself in
an `IOException("Unable to acquire X bytes of memory")` thrown by
`UnsafeExternalSorter`.
The solution is to reserve a page in each sorter in the chain before computing
the child operator's (parent RDD's) partitions. This requires us to use a new
special RDD that does some preparation before computing the parent's partitions.
Author: Andrew Or <and...@databricks.com>
Closes #8011 from andrewor14/unsafe-starve-memory and squashes the following
commits:
35b69a4 [Andrew Or] Simplify test
0b07782 [Andrew Or] Minor: update comments
5d5afdf [Andrew Or] Merge branch 'master' of github.com:apache/spark into
unsafe-starve-memory
254032e [Andrew Or] Add tests
234acbd [Andrew Or] Reserve a page in sorter when preparing each partition
b889e08 [Andrew Or] MapPartitionsWithPreparationRDD
(cherry picked from commit 014a9f9d8c9521180f7a448cc7cc96cc00537d5c)
Signed-off-by: Reynold Xin <r...@databricks.com>
Project: http://git-wip-us.apache.org/repos/asf/spark/repo
Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/472f0dc3
Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/472f0dc3
Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/472f0dc3
Branch: refs/heads/branch-1.5
Commit: 472f0dc34871c477b56308b8fcdcdd8a267185c7
Parents: 37b6403
Author: Andrew Or <and...@databricks.com>
Authored: Thu Aug 6 19:04:57 2015 -0700
Committer: Reynold Xin <r...@databricks.com>
Committed: Thu Aug 6 19:05:04 2015 -0700
----------------------------------------------------------------------
.../unsafe/sort/UnsafeExternalSorter.java | 43 +++++++++-----
.../org/apache/spark/rdd/MapPartitionsRDD.scala | 3 +
.../rdd/MapPartitionsWithPreparationRDD.scala | 49 ++++++++++++++++
.../spark/shuffle/ShuffleMemoryManager.scala | 2 +-
.../unsafe/sort/UnsafeExternalSorterSuite.java | 19 ++++++-
.../MapPartitionsWithPreparationRDDSuite.scala | 60 ++++++++++++++++++++
.../apache/spark/sql/execution/SparkPlan.scala | 2 +-
.../org/apache/spark/sql/execution/sort.scala | 28 +++++++--
8 files changed, 184 insertions(+), 22 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
----------------------------------------------------------------------
diff --git
a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
index 8f78fc5..4c54ba4 100644
---
a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
+++
b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
@@ -138,6 +138,11 @@ public final class UnsafeExternalSorter {
this.inMemSorter = existingInMemorySorter;
}
+ // Acquire a new page as soon as we construct the sorter to ensure that we
have at
+ // least one page to work with. Otherwise, other operators in the same
task may starve
+ // this sorter (SPARK-9709).
+ acquireNewPage();
+
// Register a cleanup task with TaskContext to ensure that memory is
guaranteed to be freed at
// the end of the task. This is necessary to avoid memory leaks in when
the downstream operator
// does not fully consume the sorter's output (e.g. sort followed by
limit).
@@ -343,22 +348,32 @@ public final class UnsafeExternalSorter {
throw new IOException("Required space " + requiredSpace + " is greater
than page size (" +
pageSizeBytes + ")");
} else {
- final long memoryAcquired =
shuffleMemoryManager.tryToAcquire(pageSizeBytes);
- if (memoryAcquired < pageSizeBytes) {
- shuffleMemoryManager.release(memoryAcquired);
- spill();
- final long memoryAcquiredAfterSpilling =
shuffleMemoryManager.tryToAcquire(pageSizeBytes);
- if (memoryAcquiredAfterSpilling != pageSizeBytes) {
- shuffleMemoryManager.release(memoryAcquiredAfterSpilling);
- throw new IOException("Unable to acquire " + pageSizeBytes + "
bytes of memory");
- }
- }
- currentPage = taskMemoryManager.allocatePage(pageSizeBytes);
- currentPagePosition = currentPage.getBaseOffset();
- freeSpaceInCurrentPage = pageSizeBytes;
- allocatedPages.add(currentPage);
+ acquireNewPage();
+ }
+ }
+ }
+
+ /**
+ * Acquire a new page from the {@link ShuffleMemoryManager}.
+ *
+ * If there is not enough space to allocate the new page, spill all existing
ones
+ * and try again. If there is still not enough space, report error to the
caller.
+ */
+ private void acquireNewPage() throws IOException {
+ final long memoryAcquired =
shuffleMemoryManager.tryToAcquire(pageSizeBytes);
+ if (memoryAcquired < pageSizeBytes) {
+ shuffleMemoryManager.release(memoryAcquired);
+ spill();
+ final long memoryAcquiredAfterSpilling =
shuffleMemoryManager.tryToAcquire(pageSizeBytes);
+ if (memoryAcquiredAfterSpilling != pageSizeBytes) {
+ shuffleMemoryManager.release(memoryAcquiredAfterSpilling);
+ throw new IOException("Unable to acquire " + pageSizeBytes + " bytes
of memory");
}
}
+ currentPage = taskMemoryManager.allocatePage(pageSizeBytes);
+ currentPagePosition = currentPage.getBaseOffset();
+ freeSpaceInCurrentPage = pageSizeBytes;
+ allocatedPages.add(currentPage);
}
/**
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
----------------------------------------------------------------------
diff --git a/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
index a838aac..4312d3a 100644
--- a/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
@@ -21,6 +21,9 @@ import scala.reflect.ClassTag
import org.apache.spark.{Partition, TaskContext}
+/**
+ * An RDD that applies the provided function to every partition of the parent
RDD.
+ */
private[spark] class MapPartitionsRDD[U: ClassTag, T: ClassTag](
prev: RDD[T],
f: (TaskContext, Int, Iterator[T]) => Iterator[U], // (TaskContext,
partition index, iterator)
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDD.scala
----------------------------------------------------------------------
diff --git
a/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDD.scala
b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDD.scala
new file mode 100644
index 0000000..b475bd8
--- /dev/null
+++
b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDD.scala
@@ -0,0 +1,49 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.rdd
+
+import scala.reflect.ClassTag
+
+import org.apache.spark.{Partition, Partitioner, TaskContext}
+
+/**
+ * An RDD that applies a user provided function to every partition of the
parent RDD, and
+ * additionally allows the user to prepare each partition before computing the
parent partition.
+ */
+private[spark] class MapPartitionsWithPreparationRDD[U: ClassTag, T: ClassTag,
M: ClassTag](
+ prev: RDD[T],
+ preparePartition: () => M,
+ executePartition: (TaskContext, Int, M, Iterator[T]) => Iterator[U],
+ preservesPartitioning: Boolean = false)
+ extends RDD[U](prev) {
+
+ override val partitioner: Option[Partitioner] = {
+ if (preservesPartitioning) firstParent[T].partitioner else None
+ }
+
+ override def getPartitions: Array[Partition] = firstParent[T].partitions
+
+ /**
+ * Prepare a partition before computing it from its parent.
+ */
+ override def compute(partition: Partition, context: TaskContext):
Iterator[U] = {
+ val preparedArgument = preparePartition()
+ val parentIterator = firstParent[T].iterator(partition, context)
+ executePartition(context, partition.index, preparedArgument,
parentIterator)
+ }
+}
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/core/src/main/scala/org/apache/spark/shuffle/ShuffleMemoryManager.scala
----------------------------------------------------------------------
diff --git
a/core/src/main/scala/org/apache/spark/shuffle/ShuffleMemoryManager.scala
b/core/src/main/scala/org/apache/spark/shuffle/ShuffleMemoryManager.scala
index 00c1e07..e3d229c 100644
--- a/core/src/main/scala/org/apache/spark/shuffle/ShuffleMemoryManager.scala
+++ b/core/src/main/scala/org/apache/spark/shuffle/ShuffleMemoryManager.scala
@@ -124,7 +124,7 @@ private[spark] class ShuffleMemoryManager(maxMemory: Long)
extends Logging {
}
}
-private object ShuffleMemoryManager {
+private[spark] object ShuffleMemoryManager {
/**
* Figure out the shuffle memory limit from a SparkConf. We currently have
both a fraction
* of the memory pool and a safety factor since collections can sometimes
grow bigger than
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
----------------------------------------------------------------------
diff --git
a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
index 117745f..f530037 100644
---
a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
+++
b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
@@ -340,7 +340,8 @@ public class UnsafeExternalSorterSuite {
for (int i = 0; i < numRecordsPerPage * 10; i++) {
insertNumber(sorter, i);
newPeakMemory = sorter.getPeakMemoryUsedBytes();
- if (i % numRecordsPerPage == 0) {
+ // The first page is pre-allocated on instantiation
+ if (i % numRecordsPerPage == 0 && i > 0) {
// We allocated a new page for this record, so peak memory should
change
assertEquals(previousPeakMemory + pageSizeBytes, newPeakMemory);
} else {
@@ -364,5 +365,21 @@ public class UnsafeExternalSorterSuite {
}
}
+ @Test
+ public void testReservePageOnInstantiation() throws Exception {
+ final UnsafeExternalSorter sorter = newSorter();
+ try {
+ assertEquals(1, sorter.getNumberOfAllocatedPages());
+ // Inserting a new record doesn't allocate more memory since we already
have a page
+ long peakMemory = sorter.getPeakMemoryUsedBytes();
+ insertNumber(sorter, 100);
+ assertEquals(peakMemory, sorter.getPeakMemoryUsedBytes());
+ assertEquals(1, sorter.getNumberOfAllocatedPages());
+ } finally {
+ sorter.cleanupResources();
+ assertSpillFilesWereCleanedUp();
+ }
+ }
+
}
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/core/src/test/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDDSuite.scala
----------------------------------------------------------------------
diff --git
a/core/src/test/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDDSuite.scala
b/core/src/test/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDDSuite.scala
new file mode 100644
index 0000000..c16930e
--- /dev/null
+++
b/core/src/test/scala/org/apache/spark/rdd/MapPartitionsWithPreparationRDDSuite.scala
@@ -0,0 +1,60 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.rdd
+
+import scala.collection.mutable
+
+import org.apache.spark.{LocalSparkContext, SparkContext, SparkFunSuite,
TaskContext}
+
+class MapPartitionsWithPreparationRDDSuite extends SparkFunSuite with
LocalSparkContext {
+
+ test("prepare called before parent partition is computed") {
+ sc = new SparkContext("local", "test")
+
+ // Have the parent partition push a number to the list
+ val parent = sc.parallelize(1 to 100, 1).mapPartitions { iter =>
+ TestObject.things.append(20)
+ iter
+ }
+
+ // Push a different number during the prepare phase
+ val preparePartition = () => { TestObject.things.append(10) }
+
+ // Push yet another number during the execution phase
+ val executePartition = (
+ taskContext: TaskContext,
+ partitionIndex: Int,
+ notUsed: Unit,
+ parentIterator: Iterator[Int]) => {
+ TestObject.things.append(30)
+ TestObject.things.iterator
+ }
+
+ // Verify that the numbers are pushed in the order expected
+ val result = {
+ new MapPartitionsWithPreparationRDD[Int, Int, Unit](
+ parent, preparePartition, executePartition).collect()
+ }
+ assert(result === Array(10, 20, 30))
+ }
+
+}
+
+private object TestObject {
+ val things = new mutable.ListBuffer[Int]
+}
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala
----------------------------------------------------------------------
diff --git
a/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala
b/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala
index 3fff79c..719ad43 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala
@@ -164,7 +164,7 @@ abstract class SparkPlan extends QueryPlan[SparkPlan] with
Logging with Serializ
*/
final def prepare(): Unit = {
if (prepareCalled.compareAndSet(false, true)) {
- doPrepare
+ doPrepare()
children.foreach(_.prepare())
}
}
http://git-wip-us.apache.org/repos/asf/spark/blob/472f0dc3/sql/core/src/main/scala/org/apache/spark/sql/execution/sort.scala
----------------------------------------------------------------------
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/sort.scala
b/sql/core/src/main/scala/org/apache/spark/sql/execution/sort.scala
index 3192b6e..7f69cdb 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/sort.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/sort.scala
@@ -18,7 +18,7 @@
package org.apache.spark.sql.execution
import org.apache.spark.{InternalAccumulator, TaskContext}
-import org.apache.spark.rdd.RDD
+import org.apache.spark.rdd.{MapPartitionsWithPreparationRDD, RDD}
import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.catalyst.errors._
import org.apache.spark.sql.catalyst.expressions._
@@ -123,7 +123,12 @@ case class TungstenSort(
val schema = child.schema
val childOutput = child.output
val pageSize = sparkContext.conf.getSizeAsBytes("spark.buffer.pageSize",
"64m")
- child.execute().mapPartitions({ iter =>
+
+ /**
+ * Set up the sorter in each partition before computing the parent
partition.
+ * This makes sure our sorter is not starved by other sorters used in the
same task.
+ */
+ def preparePartition(): UnsafeExternalRowSorter = {
val ordering = newOrdering(sortOrder, childOutput)
// The comparator for comparing prefix
@@ -143,12 +148,25 @@ case class TungstenSort(
if (testSpillFrequency > 0) {
sorter.setTestSpillFrequency(testSpillFrequency)
}
- val sortedIterator = sorter.sort(iter.asInstanceOf[Iterator[UnsafeRow]])
- val taskContext = TaskContext.get()
+ sorter
+ }
+
+ /** Compute a partition using the sorter already set up previously. */
+ def executePartition(
+ taskContext: TaskContext,
+ partitionIndex: Int,
+ sorter: UnsafeExternalRowSorter,
+ parentIterator: Iterator[InternalRow]): Iterator[InternalRow] = {
+ val sortedIterator =
sorter.sort(parentIterator.asInstanceOf[Iterator[UnsafeRow]])
taskContext.internalMetricsToAccumulators(
InternalAccumulator.PEAK_EXECUTION_MEMORY).add(sorter.getPeakMemoryUsage)
sortedIterator
- }, preservesPartitioning = true)
+ }
+
+ // Note: we need to set up the external sorter in each partition before
computing
+ // the parent partition, so we cannot simply use `mapPartitions` here
(SPARK-9709).
+ new MapPartitionsWithPreparationRDD[InternalRow, InternalRow,
UnsafeExternalRowSorter](
+ child.execute(), preparePartition, executePartition,
preservesPartitioning = true)
}
}
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