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/*
* 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.hash
import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.HashMap
import org.apache.spark._
import org.apache.spark.serializer.Serializer
import org.apache.spark.shuffle.FetchFailedException
import org.apache.spark.storage.{BlockId, BlockManagerId, ShuffleBlockFetcherIterator, ShuffleBlockId}
import org.apache.spark.util.CompletionIterator
private[hash] object BlockStoreShuffleFetcher extends Logging {
def fetch[T](
shuffleId: Int,
reduceId: Int,
context: TaskContext,
serializer: Serializer)
: Iterator[T] =
{
logDebug("Fetching outputs for shuffle %d, reduce %d".format(shuffleId, reduceId))
val blockManager = SparkEnv.get.blockManager
val startTime = System.currentTimeMillis
val statuses = SparkEnv.get.mapOutputTracker.getServerStatuses(shuffleId, reduceId)
logDebug("Fetching map output location for shuffle %d, reduce %d took %d ms".format(
shuffleId, reduceId, System.currentTimeMillis - startTime))
val splitsByAddress = new HashMap[BlockManagerId, ArrayBuffer[(Int, Long)]]
for (((address, size), index) <- statuses.zipWithIndex) {
splitsByAddress.getOrElseUpdate(address, ArrayBuffer()) += ((index, size))
}
val blocksByAddress: Seq[(BlockManagerId, Seq[(BlockId, Long)])] = splitsByAddress.toSeq.map {
case (address, splits) =>
(address, splits.map(s => (ShuffleBlockId(shuffleId, s._1, reduceId), s._2)))
}
def unpackBlock(blockPair: (BlockId, Option[Iterator[Any]])) : Iterator[T] = {
val blockId = blockPair._1
val blockOption = blockPair._2
blockOption match {
case Some(block) => {
block.asInstanceOf[Iterator[T]]
}
case None => {
blockId match {
case ShuffleBlockId(shufId, mapId, _) =>
val address = statuses(mapId.toInt)._1
throw new FetchFailedException(address, shufId.toInt, mapId.toInt, reduceId)
case _ =>
throw new SparkException(
"Failed to get block " + blockId + ", which is not a shuffle block")
}
}
}
}
val blockFetcherItr = new ShuffleBlockFetcherIterator(
context,
SparkEnv.get.blockTransferService,
blockManager,
blocksByAddress,
serializer,
SparkEnv.get.conf.getLong("spark.reducer.maxMbInFlight", 48) * 1024 * 1024)
val itr = blockFetcherItr.flatMap(unpackBlock)
val completionIter = CompletionIterator[T, Iterator[T]](itr, {
context.taskMetrics.updateShuffleReadMetrics()
})
new InterruptibleIterator[T](context, completionIter)
}
}
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