Github user mateiz commented on a diff in the pull request: https://github.com/apache/spark/pull/1499#discussion_r15383498 --- Diff: core/src/main/scala/org/apache/spark/shuffle/sort/SortShuffleWriter.scala --- @@ -0,0 +1,156 @@ +/* + * 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.shuffle.sort + +import java.io.{BufferedOutputStream, File, FileOutputStream, DataOutputStream} + +import org.apache.spark.{MapOutputTracker, SparkEnv, Logging, TaskContext} +import org.apache.spark.executor.ShuffleWriteMetrics +import org.apache.spark.scheduler.MapStatus +import org.apache.spark.serializer.Serializer +import org.apache.spark.shuffle.{ShuffleWriter, BaseShuffleHandle} +import org.apache.spark.storage.ShuffleBlockId +import org.apache.spark.util.collection.ExternalSorter + +private[spark] class SortShuffleWriter[K, V, C]( + handle: BaseShuffleHandle[K, V, C], + mapId: Int, + context: TaskContext) + extends ShuffleWriter[K, V] with Logging { + + private val dep = handle.dependency + private val numPartitions = dep.partitioner.numPartitions + + private val blockManager = SparkEnv.get.blockManager + private val ser = Serializer.getSerializer(dep.serializer.getOrElse(null)) + + private val conf = SparkEnv.get.conf + private val fileBufferSize = conf.getInt("spark.shuffle.file.buffer.kb", 100) * 1024 + + private var sorter: ExternalSorter[K, V, _] = null + private var outputFile: File = null + + private var stopping = false + private var mapStatus: MapStatus = null + + /** Write a bunch of records to this task's output */ + override def write(records: Iterator[_ <: Product2[K, V]]): Unit = { + val partitions: Iterator[(Int, Iterator[Product2[K, _]])] = { + if (dep.mapSideCombine) { + if (!dep.aggregator.isDefined) { + throw new IllegalStateException("Aggregator is empty for map-side combine") + } + sorter = new ExternalSorter[K, V, C]( + dep.aggregator, Some(dep.partitioner), dep.keyOrdering, dep.serializer) + sorter.write(records) + sorter.partitionedIterator + } else { + // In this case we pass neither an aggregator nor an ordering to the sorter, because we + // don't care whether the keys get sorted in each partition; that will be done on the + // reduce side if the operation being run is sortByKey. + sorter = new ExternalSorter[K, V, V]( + None, Some(dep.partitioner), None, dep.serializer) + sorter.write(records) + sorter.partitionedIterator + } + } + + // Create a single shuffle file with reduce ID 0 that we'll write all results to. We'll later + // serve different ranges of this file using an index file that we create at the end. + val blockId = ShuffleBlockId(dep.shuffleId, mapId, 0) + outputFile = blockManager.diskBlockManager.getFile(blockId) + + // Track location of each range in the output file + val offsets = new Array[Long](numPartitions + 1) + val lengths = new Array[Long](numPartitions) + + // Statistics + var totalBytes = 0L + var totalTime = 0L + + for ((id, elements) <- partitions) { + if (elements.hasNext) { + val writer = blockManager.getDiskWriter(blockId, outputFile, ser, fileBufferSize) + for (elem <- elements) { + writer.write(elem) + } + writer.commit() + writer.close() + val segment = writer.fileSegment() + offsets(id + 1) = segment.offset + segment.length + lengths(id) = segment.length + totalTime += writer.timeWriting() + totalBytes += segment.length + } else { + // Don't create a new writer to avoid writing any headers and things like that + offsets(id + 1) = offsets(id) + } + } + + val shuffleMetrics = new ShuffleWriteMetrics + shuffleMetrics.shuffleBytesWritten = totalBytes + shuffleMetrics.shuffleWriteTime = totalTime + context.taskMetrics.shuffleWriteMetrics = Some(shuffleMetrics) + context.taskMetrics.memoryBytesSpilled = sorter.memoryBytesSpilled + context.taskMetrics.diskBytesSpilled = sorter.diskBytesSpilled + + // 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 SortShuffleManager.getBlockLocation to figure + // out where each block begins and ends. + + val diskBlockManager = blockManager.diskBlockManager + val indexFile = diskBlockManager.getFile(blockId.name + ".index") + val out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(indexFile))) + try { + var i = 0 + while (i < numPartitions + 1) { + out.writeLong(offsets(i)) + i += 1 + } + } finally { + out.close() + } + + mapStatus = new MapStatus(blockManager.blockManagerId, + lengths.map(MapOutputTracker.compressSize)) --- End diff -- This can be refactored later, there's a task to move MapOutputTracker around
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