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Original file line number Diff line number Diff line change
Expand Up @@ -125,7 +125,7 @@ public void write(Iterator<Product2<K, V>> records) throws IOException {
assert (partitionWriters == null);
if (!records.hasNext()) {
partitionLengths = new long[numPartitions];
shuffleBlockResolver.writeIndexFile(shuffleId, mapId, partitionLengths);
shuffleBlockResolver.writeIndexFileAndCommit(shuffleId, mapId, partitionLengths, null);
mapStatus = MapStatus$.MODULE$.apply(blockManager.shuffleServerId(), partitionLengths);
return;
}
Expand Down Expand Up @@ -155,9 +155,10 @@ public void write(Iterator<Product2<K, V>> records) throws IOException {
writer.commitAndClose();
}

partitionLengths =
writePartitionedFile(shuffleBlockResolver.getDataFile(shuffleId, mapId));
shuffleBlockResolver.writeIndexFile(shuffleId, mapId, partitionLengths);
File output = shuffleBlockResolver.getDataFile(shuffleId, mapId);
File tmp = Utils.tempFileWith(output);
partitionLengths = writePartitionedFile(tmp);
shuffleBlockResolver.writeIndexFileAndCommit(shuffleId, mapId, partitionLengths, tmp);
mapStatus = MapStatus$.MODULE$.apply(blockManager.shuffleServerId(), partitionLengths);
}

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@
import org.apache.spark.executor.ShuffleWriteMetrics;
import org.apache.spark.io.CompressionCodec;
import org.apache.spark.io.CompressionCodec$;
import org.apache.spark.io.LZFCompressionCodec;
import org.apache.spark.memory.TaskMemoryManager;
import org.apache.spark.network.util.LimitedInputStream;
import org.apache.spark.scheduler.MapStatus;
import org.apache.spark.scheduler.MapStatus$;
Expand All @@ -53,7 +53,7 @@
import org.apache.spark.storage.BlockManager;
import org.apache.spark.storage.TimeTrackingOutputStream;
import org.apache.spark.unsafe.Platform;
import org.apache.spark.memory.TaskMemoryManager;
import org.apache.spark.util.Utils;

@Private
public class UnsafeShuffleWriter<K, V> extends ShuffleWriter<K, V> {
Expand Down Expand Up @@ -206,16 +206,18 @@ void closeAndWriteOutput() throws IOException {
final SpillInfo[] spills = sorter.closeAndGetSpills();
sorter = null;
final long[] partitionLengths;
final File output = shuffleBlockResolver.getDataFile(shuffleId, mapId);
final File tmp = Utils.tempFileWith(output);
try {
partitionLengths = mergeSpills(spills);
partitionLengths = mergeSpills(spills, tmp);
} finally {
for (SpillInfo spill : spills) {
if (spill.file.exists() && ! spill.file.delete()) {
logger.error("Error while deleting spill file {}", spill.file.getPath());
}
}
}
shuffleBlockResolver.writeIndexFile(shuffleId, mapId, partitionLengths);
shuffleBlockResolver.writeIndexFileAndCommit(shuffleId, mapId, partitionLengths, tmp);
mapStatus = MapStatus$.MODULE$.apply(blockManager.shuffleServerId(), partitionLengths);
}

Expand Down Expand Up @@ -248,8 +250,7 @@ void forceSorterToSpill() throws IOException {
*
* @return the partition lengths in the merged file.
*/
private long[] mergeSpills(SpillInfo[] spills) throws IOException {
final File outputFile = shuffleBlockResolver.getDataFile(shuffleId, mapId);
private long[] mergeSpills(SpillInfo[] spills, File outputFile) throws IOException {
final boolean compressionEnabled = sparkConf.getBoolean("spark.shuffle.compress", true);
final CompressionCodec compressionCodec = CompressionCodec$.MODULE$.createCodec(sparkConf);
final boolean fastMergeEnabled =
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -21,13 +21,13 @@ import java.util.concurrent.ConcurrentLinkedQueue

import scala.collection.JavaConverters._

import org.apache.spark.{Logging, SparkConf, SparkEnv}
import org.apache.spark.executor.ShuffleWriteMetrics
import org.apache.spark.network.buffer.{FileSegmentManagedBuffer, ManagedBuffer}
import org.apache.spark.network.netty.SparkTransportConf
import org.apache.spark.serializer.Serializer
import org.apache.spark.storage._
import org.apache.spark.util.{MetadataCleaner, MetadataCleanerType, TimeStampedHashMap}
import org.apache.spark.util.{MetadataCleaner, MetadataCleanerType, TimeStampedHashMap, Utils}
import org.apache.spark.{Logging, SparkConf, SparkEnv}

/** A group of writers for a ShuffleMapTask, one writer per reducer. */
private[spark] trait ShuffleWriterGroup {
Expand Down Expand Up @@ -84,17 +84,8 @@ private[spark] class FileShuffleBlockResolver(conf: SparkConf)
Array.tabulate[DiskBlockObjectWriter](numReducers) { bucketId =>
val blockId = ShuffleBlockId(shuffleId, mapId, bucketId)
val blockFile = blockManager.diskBlockManager.getFile(blockId)
// Because of previous failures, the shuffle file may already exist on this machine.
// If so, remove it.
if (blockFile.exists) {
if (blockFile.delete()) {
logInfo(s"Removed existing shuffle file $blockFile")
} else {
logWarning(s"Failed to remove existing shuffle file $blockFile")
}
}
blockManager.getDiskWriter(blockId, blockFile, serializerInstance, bufferSize,
writeMetrics)
val tmp = Utils.tempFileWith(blockFile)
blockManager.getDiskWriter(blockId, tmp, serializerInstance, bufferSize, writeMetrics)
}
}
// Creating the file to write to and creating a disk writer both involve interacting with
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -21,13 +21,12 @@ import java.io._

import com.google.common.io.ByteStreams

import org.apache.spark.{SparkConf, SparkEnv, Logging}
import org.apache.spark.network.buffer.{FileSegmentManagedBuffer, ManagedBuffer}
import org.apache.spark.network.netty.SparkTransportConf
import org.apache.spark.shuffle.IndexShuffleBlockResolver.NOOP_REDUCE_ID
import org.apache.spark.storage._
import org.apache.spark.util.Utils

import IndexShuffleBlockResolver.NOOP_REDUCE_ID
import org.apache.spark.{SparkEnv, Logging, SparkConf}

/**
* Create and maintain the shuffle blocks' mapping between logic block and physical file location.
Expand All @@ -40,10 +39,13 @@ import IndexShuffleBlockResolver.NOOP_REDUCE_ID
*/
// Note: Changes to the format in this file should be kept in sync with
// org.apache.spark.network.shuffle.ExternalShuffleBlockResolver#getSortBasedShuffleBlockData().
private[spark] class IndexShuffleBlockResolver(conf: SparkConf) extends ShuffleBlockResolver
private[spark] class IndexShuffleBlockResolver(
conf: SparkConf,
_blockManager: BlockManager = null)
extends ShuffleBlockResolver
with Logging {

private lazy val blockManager = SparkEnv.get.blockManager
private lazy val blockManager = Option(_blockManager).getOrElse(SparkEnv.get.blockManager)

private val transportConf = SparkTransportConf.fromSparkConf(conf)

Expand Down Expand Up @@ -74,14 +76,69 @@ private[spark] class IndexShuffleBlockResolver(conf: SparkConf) extends ShuffleB
}
}

/**
* Check whether the given index and data files match each other.
* If so, return the partition lengths in the data file. Otherwise return null.
*/
private def checkIndexAndDataFile(index: File, data: File, blocks: Int): Array[Long] = {
// the index file should have `block + 1` longs as offset.
if (index.length() != (blocks + 1) * 8) {
return null
}
val lengths = new Array[Long](blocks)
// Read the lengths of blocks
val in = try {
new DataInputStream(new BufferedInputStream(new FileInputStream(index)))
} catch {
case e: IOException =>
return null
}
try {
// Convert the offsets into lengths of each block
var offset = in.readLong()
if (offset != 0L) {
return null
}
var i = 0
while (i < blocks) {
val off = in.readLong()
lengths(i) = off - offset
offset = off
i += 1
}
} catch {
case e: IOException =>
return null
} finally {
in.close()
}

// the size of data file should match with index file
if (data.length() == lengths.sum) {
lengths
} else {
null
}
}

/**
* Write an index file with the offsets of each block, plus a final offset at the end for the
* end of the output file. This will be used by getBlockData to figure out where each block
* begins and ends.
*
* It will commit the data and index file as an atomic operation, use the existing ones, or
* replace them with new ones.
*
* Note: the `lengths` will be updated to match the existing index file if use the existing ones.
* */
def writeIndexFile(shuffleId: Int, mapId: Int, lengths: Array[Long]): Unit = {
def writeIndexFileAndCommit(
shuffleId: Int,
mapId: Int,
lengths: Array[Long],
dataTmp: File): Unit = {
val indexFile = getIndexFile(shuffleId, mapId)
val out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(indexFile)))
val indexTmp = Utils.tempFileWith(indexFile)
val out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(indexTmp)))
Utils.tryWithSafeFinally {
// We take in lengths of each block, need to convert it to offsets.
var offset = 0L
Expand All @@ -93,6 +150,37 @@ private[spark] class IndexShuffleBlockResolver(conf: SparkConf) extends ShuffleB
} {
out.close()
}

val dataFile = getDataFile(shuffleId, mapId)
// There is only one IndexShuffleBlockResolver per executor, this synchronization make sure
// the following check and rename are atomic.
synchronized {
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Can you add a big comment explaining what is going on here? Also worth noting that there is only one IndexShuffleBlockResolver per executor.

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is this synchronized for atomic renames? If so, can you mention in a comment?

val existingLengths = checkIndexAndDataFile(indexFile, dataFile, lengths.length)
if (existingLengths != null) {
// Another attempt for the same task has already written our map outputs successfully,
// so just use the existing partition lengths and delete our temporary map outputs.
System.arraycopy(existingLengths, 0, lengths, 0, lengths.length)
if (dataTmp != null && dataTmp.exists()) {
dataTmp.delete()
}
indexTmp.delete()
} else {
// This is the first successful attempt in writing the map outputs for this task,
// so override any existing index and data files with the ones we wrote.
if (indexFile.exists()) {
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// This is the first successful attempt in writing the map outputs for this task,
// so override any existing index and data files with the ones we wrote.

indexFile.delete()
}
if (dataFile.exists()) {
dataFile.delete()
}
if (!indexTmp.renameTo(indexFile)) {
throw new IOException("fail to rename file " + indexTmp + " to " + indexFile)
}
if (dataTmp != null && dataTmp.exists() && !dataTmp.renameTo(dataFile)) {
throw new IOException("fail to rename file " + dataTmp + " to " + dataFile)
}
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should we check

checkIndexAndDataFile(indexTmp, dataTmp, lengths.length) != null

what happens if this fails? Should we throw an exception?

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This will slowdown the normal path, I think it's not needed.

}
}
}

override def getBlockData(blockId: ShuffleBlockId): ManagedBuffer = {
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@

package org.apache.spark.shuffle.hash

import java.io.IOException

import org.apache.spark._
import org.apache.spark.executor.ShuffleWriteMetrics
import org.apache.spark.scheduler.MapStatus
Expand Down Expand Up @@ -106,6 +108,29 @@ private[spark] class HashShuffleWriter[K, V](
writer.commitAndClose()
writer.fileSegment().length
}
// rename all shuffle files to final paths
// Note: there is only one ShuffleBlockResolver in executor
shuffleBlockResolver.synchronized {
shuffle.writers.zipWithIndex.foreach { case (writer, i) =>
val output = blockManager.diskBlockManager.getFile(writer.blockId)
if (sizes(i) > 0) {
if (output.exists()) {
// Use length of existing file and delete our own temporary one
sizes(i) = output.length()
writer.file.delete()
} else {
// Commit by renaming our temporary file to something the fetcher expects
if (!writer.file.renameTo(output)) {
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// Commit by renaming our temporary file to something the fetcher expects

throw new IOException(s"fail to rename ${writer.file} to $output")
}
}
} else {
if (output.exists()) {
output.delete()
}
}
}
}
MapStatus(blockManager.shuffleServerId, sizes)
}

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -20,8 +20,9 @@ package org.apache.spark.shuffle.sort
import org.apache.spark._
import org.apache.spark.executor.ShuffleWriteMetrics
import org.apache.spark.scheduler.MapStatus
import org.apache.spark.shuffle.{IndexShuffleBlockResolver, ShuffleWriter, BaseShuffleHandle}
import org.apache.spark.shuffle.{BaseShuffleHandle, IndexShuffleBlockResolver, ShuffleWriter}
import org.apache.spark.storage.ShuffleBlockId
import org.apache.spark.util.Utils
import org.apache.spark.util.collection.ExternalSorter

private[spark] class SortShuffleWriter[K, V, C](
Expand Down Expand Up @@ -65,11 +66,11 @@ private[spark] class SortShuffleWriter[K, V, C](
// Don't bother including the time to open the merged output file in the shuffle write time,
// because it just opens a single file, so is typically too fast to measure accurately
// (see SPARK-3570).
val outputFile = shuffleBlockResolver.getDataFile(dep.shuffleId, mapId)
val output = shuffleBlockResolver.getDataFile(dep.shuffleId, mapId)
val tmp = Utils.tempFileWith(output)
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can you call these outputTmp or something so it's slightly easier to follow? (here and other places)

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This is only one file output here, I think it's obvious

val blockId = ShuffleBlockId(dep.shuffleId, mapId, IndexShuffleBlockResolver.NOOP_REDUCE_ID)
val partitionLengths = sorter.writePartitionedFile(blockId, outputFile)
shuffleBlockResolver.writeIndexFile(dep.shuffleId, mapId, partitionLengths)

val partitionLengths = sorter.writePartitionedFile(blockId, tmp)
shuffleBlockResolver.writeIndexFileAndCommit(dep.shuffleId, mapId, partitionLengths, tmp)
mapStatus = MapStatus(blockManager.shuffleServerId, partitionLengths)
}

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -21,10 +21,10 @@ import java.io._
import java.nio.{ByteBuffer, MappedByteBuffer}

import scala.collection.mutable.{ArrayBuffer, HashMap}
import scala.concurrent.{ExecutionContext, Await, Future}
import scala.concurrent.duration._
import scala.util.control.NonFatal
import scala.concurrent.{Await, ExecutionContext, Future}
import scala.util.Random
import scala.util.control.NonFatal

import sun.nio.ch.DirectBuffer

Expand All @@ -38,9 +38,8 @@ import org.apache.spark.network.netty.SparkTransportConf
import org.apache.spark.network.shuffle.ExternalShuffleClient
import org.apache.spark.network.shuffle.protocol.ExecutorShuffleInfo
import org.apache.spark.rpc.RpcEnv
import org.apache.spark.serializer.{SerializerInstance, Serializer}
import org.apache.spark.serializer.{Serializer, SerializerInstance}
import org.apache.spark.shuffle.ShuffleManager
import org.apache.spark.shuffle.hash.HashShuffleManager
import org.apache.spark.util._

private[spark] sealed trait BlockValues
Expand Down Expand Up @@ -660,7 +659,7 @@ private[spark] class BlockManager(
val compressStream: OutputStream => OutputStream = wrapForCompression(blockId, _)
val syncWrites = conf.getBoolean("spark.shuffle.sync", false)
new DiskBlockObjectWriter(file, serializerInstance, bufferSize, compressStream,
syncWrites, writeMetrics)
syncWrites, writeMetrics, blockId)
}

/**
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -34,14 +34,15 @@ import org.apache.spark.util.Utils
* reopened again.
*/
private[spark] class DiskBlockObjectWriter(
file: File,
val file: File,
serializerInstance: SerializerInstance,
bufferSize: Int,
compressStream: OutputStream => OutputStream,
syncWrites: Boolean,
// These write metrics concurrently shared with other active DiskBlockObjectWriters who
// are themselves performing writes. All updates must be relative.
writeMetrics: ShuffleWriteMetrics)
writeMetrics: ShuffleWriteMetrics,
val blockId: BlockId = null)
extends OutputStream
with Logging {

Expand Down
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