spark ShuffleBlockFetcherIterator 源码
spark ShuffleBlockFetcherIterator 代码
文件路径：/core/src/main/scala/org/apache/spark/storage/ShuffleBlockFetcherIterator.scala
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* 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
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
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* See the License for the specific language governing permissions and
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package org.apache.spark.storage
import java.io.{InputStream, IOException}
import java.nio.channels.ClosedByInterruptException
import java.util.concurrent.{LinkedBlockingQueue, TimeUnit}
import java.util.concurrent.atomic.AtomicBoolean
import java.util.zip.CheckedInputStream
import javax.annotation.concurrent.GuardedBy
import scala.collection.mutable
import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet, Queue}
import scala.util.{Failure, Success}
import io.netty.util.internal.OutOfDirectMemoryError
import org.apache.commons.io.IOUtils
import org.roaringbitmap.RoaringBitmap
import org.apache.spark.{MapOutputTracker, TaskContext}
import org.apache.spark.MapOutputTracker.SHUFFLE_PUSH_MAP_ID
import org.apache.spark.errors.SparkCoreErrors
import org.apache.spark.internal.Logging
import org.apache.spark.network.buffer.{FileSegmentManagedBuffer, ManagedBuffer}
import org.apache.spark.network.shuffle._
import org.apache.spark.network.shuffle.checksum.{Cause, ShuffleChecksumHelper}
import org.apache.spark.network.util.{NettyUtils, TransportConf}
import org.apache.spark.shuffle.ShuffleReadMetricsReporter
import org.apache.spark.util.{CompletionIterator, TaskCompletionListener, Utils}
/**
* An iterator that fetches multiple blocks. For local blocks, it fetches from the local block
* manager. For remote blocks, it fetches them using the provided BlockTransferService.
*
* This creates an iterator of (BlockID, InputStream) tuples so the caller can handle blocks
* in a pipelined fashion as they are received.
*
* The implementation throttles the remote fetches so they don't exceed maxBytesInFlight to avoid
* using too much memory.
*
* @param context [[TaskContext]], used for metrics update
* @param shuffleClient [[BlockStoreClient]] for fetching remote blocks
* @param blockManager [[BlockManager]] for reading local blocks
* @param blocksByAddress list of blocks to fetch grouped by the [[BlockManagerId]].
* For each block we also require two info: 1. the size (in bytes as a long
* field) in order to throttle the memory usage; 2. the mapIndex for this
* block, which indicate the index in the map stage.
* Note that zero-sized blocks are already excluded, which happened in
* [[org.apache.spark.MapOutputTracker.convertMapStatuses]].
* @param mapOutputTracker [[MapOutputTracker]] for falling back to fetching the original blocks if
* we fail to fetch shuffle chunks when push based shuffle is enabled.
* @param streamWrapper A function to wrap the returned input stream.
* @param maxBytesInFlight max size (in bytes) of remote blocks to fetch at any given point.
* @param maxReqsInFlight max number of remote requests to fetch blocks at any given point.
* @param maxBlocksInFlightPerAddress max number of shuffle blocks being fetched at any given point
* for a given remote host:port.
* @param maxReqSizeShuffleToMem max size (in bytes) of a request that can be shuffled to memory.
* @param maxAttemptsOnNettyOOM The max number of a block could retry due to Netty OOM before
* throwing the fetch failure.
* @param detectCorrupt whether to detect any corruption in fetched blocks.
* @param checksumEnabled whether the shuffle checksum is enabled. When enabled, Spark will try to
* diagnose the cause of the block corruption.
* @param checksumAlgorithm the checksum algorithm that is used when calculating the checksum value
* for the block data.
* @param shuffleMetrics used to report shuffle metrics.
* @param doBatchFetch fetch continuous shuffle blocks from same executor in batch if the server
* side supports.
*/
private[spark]
final class ShuffleBlockFetcherIterator(
context: TaskContext,
shuffleClient: BlockStoreClient,
blockManager: BlockManager,
mapOutputTracker: MapOutputTracker,
blocksByAddress: Iterator[(BlockManagerId, Seq[(BlockId, Long, Int)])],
streamWrapper: (BlockId, InputStream) => InputStream,
maxBytesInFlight: Long,
maxReqsInFlight: Int,
maxBlocksInFlightPerAddress: Int,
val maxReqSizeShuffleToMem: Long,
maxAttemptsOnNettyOOM: Int,
detectCorrupt: Boolean,
detectCorruptUseExtraMemory: Boolean,
checksumEnabled: Boolean,
checksumAlgorithm: String,
shuffleMetrics: ShuffleReadMetricsReporter,
doBatchFetch: Boolean)
extends Iterator[(BlockId, InputStream)] with DownloadFileManager with Logging {
import ShuffleBlockFetcherIterator._
// Make remote requests at most maxBytesInFlight / 5 in length; the reason to keep them
// smaller than maxBytesInFlight is to allow multiple, parallel fetches from up to 5
// nodes, rather than blocking on reading output from one node.
private val targetRemoteRequestSize = math.max(maxBytesInFlight / 5, 1L)
/**
* Total number of blocks to fetch.
*/
private[this] var numBlocksToFetch = 0
/**
* The number of blocks processed by the caller. The iterator is exhausted when
* [[numBlocksProcessed]] == [[numBlocksToFetch]].
*/
private[this] var numBlocksProcessed = 0
private[this] val startTimeNs = System.nanoTime()
/** Host local blocks to fetch, excluding zero-sized blocks. */
private[this] val hostLocalBlocks = scala.collection.mutable.LinkedHashSet[(BlockId, Int)]()
/**
* A queue to hold our results. This turns the asynchronous model provided by
* [[org.apache.spark.network.BlockTransferService]] into a synchronous model (iterator).
*/
private[this] val results = new LinkedBlockingQueue[FetchResult]
/**
* Current [[FetchResult]] being processed. We track this so we can release the current buffer
* in case of a runtime exception when processing the current buffer.
*/
@volatile private[this] var currentResult: SuccessFetchResult = null
/**
* Queue of fetch requests to issue; we'll pull requests off this gradually to make sure that
* the number of bytes in flight is limited to maxBytesInFlight.
*/
private[this] val fetchRequests = new Queue[FetchRequest]
/**
* Queue of fetch requests which could not be issued the first time they were dequeued. These
* requests are tried again when the fetch constraints are satisfied.
*/
private[this] val deferredFetchRequests = new HashMap[BlockManagerId, Queue[FetchRequest]]()
/** Current bytes in flight from our requests */
private[this] var bytesInFlight = 0L
/** Current number of requests in flight */
private[this] var reqsInFlight = 0
/** Current number of blocks in flight per host:port */
private[this] val numBlocksInFlightPerAddress = new HashMap[BlockManagerId, Int]()
/**
* Count the retry times for the blocks due to Netty OOM. The block will stop retry if
* retry times has exceeded the [[maxAttemptsOnNettyOOM]].
*/
private[this] val blockOOMRetryCounts = new HashMap[String, Int]
/**
* The blocks that can't be decompressed successfully, it is used to guarantee that we retry
* at most once for those corrupted blocks.
*/
private[this] val corruptedBlocks = mutable.HashSet[BlockId]()
/**
* Whether the iterator is still active. If isZombie is true, the callback interface will no
* longer place fetched blocks into [[results]].
*/
@GuardedBy("this")
private[this] var isZombie = false
/**
* A set to store the files used for shuffling remote huge blocks. Files in this set will be
* deleted when cleanup. This is a layer of defensiveness against disk file leaks.
*/
@GuardedBy("this")
private[this] val shuffleFilesSet = mutable.HashSet[DownloadFile]()
private[this] val onCompleteCallback = new ShuffleFetchCompletionListener(this)
private[this] val pushBasedFetchHelper = new PushBasedFetchHelper(
this, shuffleClient, blockManager, mapOutputTracker)
initialize()
// Decrements the buffer reference count.
// The currentResult is set to null to prevent releasing the buffer again on cleanup()
private[storage] def releaseCurrentResultBuffer(): Unit = {
// Release the current buffer if necessary
if (currentResult != null) {
currentResult.buf.release()
}
currentResult = null
}
override def createTempFile(transportConf: TransportConf): DownloadFile = {
// we never need to do any encryption or decryption here, regardless of configs, because that
// is handled at another layer in the code. When encryption is enabled, shuffle data is written
// to disk encrypted in the first place, and sent over the network still encrypted.
new SimpleDownloadFile(
blockManager.diskBlockManager.createTempLocalBlock()._2, transportConf)
}
override def registerTempFileToClean(file: DownloadFile): Boolean = synchronized {
if (isZombie) {
false
} else {
shuffleFilesSet += file
true
}
}
/**
* Mark the iterator as zombie, and release all buffers that haven't been deserialized yet.
*/
private[storage] def cleanup(): Unit = {
synchronized {
isZombie = true
}
releaseCurrentResultBuffer()
// Release buffers in the results queue
val iter = results.iterator()
while (iter.hasNext) {
val result = iter.next()
result match {
case SuccessFetchResult(blockId, mapIndex, address, _, buf, _) =>
if (address != blockManager.blockManagerId) {
if (hostLocalBlocks.contains(blockId -> mapIndex)) {
shuffleMetrics.incLocalBlocksFetched(1)
shuffleMetrics.incLocalBytesRead(buf.size)
} else {
shuffleMetrics.incRemoteBytesRead(buf.size)
if (buf.isInstanceOf[FileSegmentManagedBuffer]) {
shuffleMetrics.incRemoteBytesReadToDisk(buf.size)
}
shuffleMetrics.incRemoteBlocksFetched(1)
}
}
buf.release()
case _ =>
}
}
shuffleFilesSet.foreach { file =>
if (!file.delete()) {
logWarning("Failed to cleanup shuffle fetch temp file " + file.path())
}
}
}
private[this] def sendRequest(req: FetchRequest): Unit = {
logDebug("Sending request for %d blocks (%s) from %s".format(
req.blocks.size, Utils.bytesToString(req.size), req.address.hostPort))
bytesInFlight += req.size
reqsInFlight += 1
// so we can look up the block info of each blockID
val infoMap = req.blocks.map {
case FetchBlockInfo(blockId, size, mapIndex) => (blockId.toString, (size, mapIndex))
}.toMap
val remainingBlocks = new HashSet[String]() ++= infoMap.keys
val deferredBlocks = new ArrayBuffer[String]()
val blockIds = req.blocks.map(_.blockId.toString)
val address = req.address
@inline def enqueueDeferredFetchRequestIfNecessary(): Unit = {
if (remainingBlocks.isEmpty && deferredBlocks.nonEmpty) {
val blocks = deferredBlocks.map { blockId =>
val (size, mapIndex) = infoMap(blockId)
FetchBlockInfo(BlockId(blockId), size, mapIndex)
}
results.put(DeferFetchRequestResult(FetchRequest(address, blocks.toSeq)))
deferredBlocks.clear()
}
}
val blockFetchingListener = new BlockFetchingListener {
override def onBlockFetchSuccess(blockId: String, buf: ManagedBuffer): Unit = {
// Only add the buffer to results queue if the iterator is not zombie,
// i.e. cleanup() has not been called yet.
ShuffleBlockFetcherIterator.this.synchronized {
if (!isZombie) {
// Increment the ref count because we need to pass this to a different thread.
// This needs to be released after use.
buf.retain()
remainingBlocks -= blockId
blockOOMRetryCounts.remove(blockId)
results.put(new SuccessFetchResult(BlockId(blockId), infoMap(blockId)._2,
address, infoMap(blockId)._1, buf, remainingBlocks.isEmpty))
logDebug("remainingBlocks: " + remainingBlocks)
enqueueDeferredFetchRequestIfNecessary()
}
}
logTrace(s"Got remote block $blockId after ${Utils.getUsedTimeNs(startTimeNs)}")
}
override def onBlockFetchFailure(blockId: String, e: Throwable): Unit = {
ShuffleBlockFetcherIterator.this.synchronized {
logError(s"Failed to get block(s) from ${req.address.host}:${req.address.port}", e)
e match {
// SPARK-27991: Catch the Netty OOM and set the flag `isNettyOOMOnShuffle` (shared among
// tasks) to true as early as possible. The pending fetch requests won't be sent
// afterwards until the flag is set to false on:
// 1) the Netty free memory >= maxReqSizeShuffleToMem
// - we'll check this whenever there's a fetch request succeeds.
// 2) the number of in-flight requests becomes 0
// - we'll check this in `fetchUpToMaxBytes` whenever it's invoked.
// Although Netty memory is shared across multiple modules, e.g., shuffle, rpc, the flag
// only takes effect for the shuffle due to the implementation simplicity concern.
// And we'll buffer the consecutive block failures caused by the OOM error until there's
// no remaining blocks in the current request. Then, we'll package these blocks into
// a same fetch request for the retry later. In this way, instead of creating the fetch
// request per block, it would help reduce the concurrent connections and data loads
// pressure at remote server.
// Note that catching OOM and do something based on it is only a workaround for
// handling the Netty OOM issue, which is not the best way towards memory management.
// We can get rid of it when we find a way to manage Netty's memory precisely.
case _: OutOfDirectMemoryError
if blockOOMRetryCounts.getOrElseUpdate(blockId, 0) < maxAttemptsOnNettyOOM =>
if (!isZombie) {
val failureTimes = blockOOMRetryCounts(blockId)
blockOOMRetryCounts(blockId) += 1
if (isNettyOOMOnShuffle.compareAndSet(false, true)) {
// The fetcher can fail remaining blocks in batch for the same error. So we only
// log the warning once to avoid flooding the logs.
logInfo(s"Block $blockId has failed $failureTimes times " +
s"due to Netty OOM, will retry")
}
remainingBlocks -= blockId
deferredBlocks += blockId
enqueueDeferredFetchRequestIfNecessary()
}
case _ =>
val block = BlockId(blockId)
if (block.isShuffleChunk) {
remainingBlocks -= blockId
results.put(FallbackOnPushMergedFailureResult(
block, address, infoMap(blockId)._1, remainingBlocks.isEmpty))
} else {
results.put(FailureFetchResult(block, infoMap(blockId)._2, address, e))
}
}
}
}
}
// Fetch remote shuffle blocks to disk when the request is too large. Since the shuffle data is
// already encrypted and compressed over the wire(w.r.t. the related configs), we can just fetch
// the data and write it to file directly.
if (req.size > maxReqSizeShuffleToMem) {
shuffleClient.fetchBlocks(address.host, address.port, address.executorId, blockIds.toArray,
blockFetchingListener, this)
} else {
shuffleClient.fetchBlocks(address.host, address.port, address.executorId, blockIds.toArray,
blockFetchingListener, null)
}
}
/**
* This is called from initialize and also from the fallback which is triggered from
* [[PushBasedFetchHelper]].
*/
private[this] def partitionBlocksByFetchMode(
blocksByAddress: Iterator[(BlockManagerId, Seq[(BlockId, Long, Int)])],
localBlocks: mutable.LinkedHashSet[(BlockId, Int)],
hostLocalBlocksByExecutor: mutable.LinkedHashMap[BlockManagerId, Seq[(BlockId, Long, Int)]],
pushMergedLocalBlocks: mutable.LinkedHashSet[BlockId]): ArrayBuffer[FetchRequest] = {
logDebug(s"maxBytesInFlight: $maxBytesInFlight, targetRemoteRequestSize: "
+ s"$targetRemoteRequestSize, maxBlocksInFlightPerAddress: $maxBlocksInFlightPerAddress")
// Partition to local, host-local, push-merged-local, remote (includes push-merged-remote)
// blocks.Remote blocks are further split into FetchRequests of size at most maxBytesInFlight
// in order to limit the amount of data in flight
val collectedRemoteRequests = new ArrayBuffer[FetchRequest]
var localBlockBytes = 0L
var hostLocalBlockBytes = 0L
var numHostLocalBlocks = 0
var pushMergedLocalBlockBytes = 0L
val prevNumBlocksToFetch = numBlocksToFetch
val fallback = FallbackStorage.FALLBACK_BLOCK_MANAGER_ID.executorId
val localExecIds = Set(blockManager.blockManagerId.executorId, fallback)
for ((address, blockInfos) <- blocksByAddress) {
checkBlockSizes(blockInfos)
if (pushBasedFetchHelper.isPushMergedShuffleBlockAddress(address)) {
// These are push-merged blocks or shuffle chunks of these blocks.
if (address.host == blockManager.blockManagerId.host) {
numBlocksToFetch += blockInfos.size
pushMergedLocalBlocks ++= blockInfos.map(_._1)
pushMergedLocalBlockBytes += blockInfos.map(_._2).sum
} else {
collectFetchRequests(address, blockInfos, collectedRemoteRequests)
}
} else if (localExecIds.contains(address.executorId)) {
val mergedBlockInfos = mergeContinuousShuffleBlockIdsIfNeeded(
blockInfos.map(info => FetchBlockInfo(info._1, info._2, info._3)), doBatchFetch)
numBlocksToFetch += mergedBlockInfos.size
localBlocks ++= mergedBlockInfos.map(info => (info.blockId, info.mapIndex))
localBlockBytes += mergedBlockInfos.map(_.size).sum
} else if (blockManager.hostLocalDirManager.isDefined &&
address.host == blockManager.blockManagerId.host) {
val mergedBlockInfos = mergeContinuousShuffleBlockIdsIfNeeded(
blockInfos.map(info => FetchBlockInfo(info._1, info._2, info._3)), doBatchFetch)
numBlocksToFetch += mergedBlockInfos.size
val blocksForAddress =
mergedBlockInfos.map(info => (info.blockId, info.size, info.mapIndex))
hostLocalBlocksByExecutor += address -> blocksForAddress
numHostLocalBlocks += blocksForAddress.size
hostLocalBlockBytes += mergedBlockInfos.map(_.size).sum
} else {
val (_, timeCost) = Utils.timeTakenMs[Unit] {
collectFetchRequests(address, blockInfos, collectedRemoteRequests)
}
logDebug(s"Collected remote fetch requests for $address in $timeCost ms")
}
}
val (remoteBlockBytes, numRemoteBlocks) =
collectedRemoteRequests.foldLeft((0L, 0))((x, y) => (x._1 + y.size, x._2 + y.blocks.size))
val totalBytes = localBlockBytes + remoteBlockBytes + hostLocalBlockBytes +
pushMergedLocalBlockBytes
val blocksToFetchCurrentIteration = numBlocksToFetch - prevNumBlocksToFetch
assert(blocksToFetchCurrentIteration == localBlocks.size +
numHostLocalBlocks + numRemoteBlocks + pushMergedLocalBlocks.size,
s"The number of non-empty blocks $blocksToFetchCurrentIteration doesn't equal to the sum " +
s"of the number of local blocks ${localBlocks.size} + " +
s"the number of host-local blocks ${numHostLocalBlocks} " +
s"the number of push-merged-local blocks ${pushMergedLocalBlocks.size} " +
s"+ the number of remote blocks ${numRemoteBlocks} ")
logInfo(s"Getting $blocksToFetchCurrentIteration " +
s"(${Utils.bytesToString(totalBytes)}) non-empty blocks including " +
s"${localBlocks.size} (${Utils.bytesToString(localBlockBytes)}) local and " +
s"${numHostLocalBlocks} (${Utils.bytesToString(hostLocalBlockBytes)}) " +
s"host-local and ${pushMergedLocalBlocks.size} " +
s"(${Utils.bytesToString(pushMergedLocalBlockBytes)}) " +
s"push-merged-local and $numRemoteBlocks (${Utils.bytesToString(remoteBlockBytes)}) " +
s"remote blocks")
this.hostLocalBlocks ++= hostLocalBlocksByExecutor.values
.flatMap { infos => infos.map(info => (info._1, info._3)) }
collectedRemoteRequests
}
private def createFetchRequest(
blocks: Seq[FetchBlockInfo],
address: BlockManagerId,
forMergedMetas: Boolean): FetchRequest = {
logDebug(s"Creating fetch request of ${blocks.map(_.size).sum} at $address "
+ s"with ${blocks.size} blocks")
FetchRequest(address, blocks, forMergedMetas)
}
private def createFetchRequests(
curBlocks: Seq[FetchBlockInfo],
address: BlockManagerId,
isLast: Boolean,
collectedRemoteRequests: ArrayBuffer[FetchRequest],
enableBatchFetch: Boolean,
forMergedMetas: Boolean = false): ArrayBuffer[FetchBlockInfo] = {
val mergedBlocks = mergeContinuousShuffleBlockIdsIfNeeded(curBlocks, enableBatchFetch)
numBlocksToFetch += mergedBlocks.size
val retBlocks = new ArrayBuffer[FetchBlockInfo]
if (mergedBlocks.length <= maxBlocksInFlightPerAddress) {
collectedRemoteRequests += createFetchRequest(mergedBlocks, address, forMergedMetas)
} else {
mergedBlocks.grouped(maxBlocksInFlightPerAddress).foreach { blocks =>
if (blocks.length == maxBlocksInFlightPerAddress || isLast) {
collectedRemoteRequests += createFetchRequest(blocks, address, forMergedMetas)
} else {
// The last group does not exceed `maxBlocksInFlightPerAddress`. Put it back
// to `curBlocks`.
retBlocks ++= blocks
numBlocksToFetch -= blocks.size
}
}
}
retBlocks
}
private def collectFetchRequests(
address: BlockManagerId,
blockInfos: Seq[(BlockId, Long, Int)],
collectedRemoteRequests: ArrayBuffer[FetchRequest]): Unit = {
val iterator = blockInfos.iterator
var curRequestSize = 0L
var curBlocks = new ArrayBuffer[FetchBlockInfo]()
while (iterator.hasNext) {
val (blockId, size, mapIndex) = iterator.next()
curBlocks += FetchBlockInfo(blockId, size, mapIndex)
curRequestSize += size
blockId match {
// Either all blocks are push-merged blocks, shuffle chunks, or original blocks.
// Based on these types, we decide to do batch fetch and create FetchRequests with
// forMergedMetas set.
case ShuffleBlockChunkId(_, _, _, _) =>
if (curRequestSize >= targetRemoteRequestSize ||
curBlocks.size >= maxBlocksInFlightPerAddress) {
curBlocks = createFetchRequests(curBlocks.toSeq, address, isLast = false,
collectedRemoteRequests, enableBatchFetch = false)
curRequestSize = curBlocks.map(_.size).sum
}
case ShuffleMergedBlockId(_, _, _) =>
if (curBlocks.size >= maxBlocksInFlightPerAddress) {
curBlocks = createFetchRequests(curBlocks.toSeq, address, isLast = false,
collectedRemoteRequests, enableBatchFetch = false, forMergedMetas = true)
}
case _ =>
// For batch fetch, the actual block in flight should count for merged block.
val mayExceedsMaxBlocks = !doBatchFetch && curBlocks.size >= maxBlocksInFlightPerAddress
if (curRequestSize >= targetRemoteRequestSize || mayExceedsMaxBlocks) {
curBlocks = createFetchRequests(curBlocks.toSeq, address, isLast = false,
collectedRemoteRequests, doBatchFetch)
curRequestSize = curBlocks.map(_.size).sum
}
}
}
// Add in the final request
if (curBlocks.nonEmpty) {
val (enableBatchFetch, forMergedMetas) = {
curBlocks.head.blockId match {
case ShuffleBlockChunkId(_, _, _, _) => (false, false)
case ShuffleMergedBlockId(_, _, _) => (false, true)
case _ => (doBatchFetch, false)
}
}
createFetchRequests(curBlocks.toSeq, address, isLast = true, collectedRemoteRequests,
enableBatchFetch = enableBatchFetch, forMergedMetas = forMergedMetas)
}
}
private def assertPositiveBlockSize(blockId: BlockId, blockSize: Long): Unit = {
if (blockSize < 0) {
throw BlockException(blockId, "Negative block size " + size)
} else if (blockSize == 0) {
throw BlockException(blockId, "Zero-sized blocks should be excluded.")
}
}
private def checkBlockSizes(blockInfos: Seq[(BlockId, Long, Int)]): Unit = {
blockInfos.foreach { case (blockId, size, _) => assertPositiveBlockSize(blockId, size) }
}
/**
* Fetch the local blocks while we are fetching remote blocks. This is ok because
* `ManagedBuffer`'s memory is allocated lazily when we create the input stream, so all we
* track in-memory are the ManagedBuffer references themselves.
*/
private[this] def fetchLocalBlocks(
localBlocks: mutable.LinkedHashSet[(BlockId, Int)]): Unit = {
logDebug(s"Start fetching local blocks: ${localBlocks.mkString(", ")}")
val iter = localBlocks.iterator
while (iter.hasNext) {
val (blockId, mapIndex) = iter.next()
try {
val buf = blockManager.getLocalBlockData(blockId)
shuffleMetrics.incLocalBlocksFetched(1)
shuffleMetrics.incLocalBytesRead(buf.size)
buf.retain()
results.put(new SuccessFetchResult(blockId, mapIndex, blockManager.blockManagerId,
buf.size(), buf, false))
} catch {
// If we see an exception, stop immediately.
case e: Exception =>
e match {
// ClosedByInterruptException is an excepted exception when kill task,
// don't log the exception stack trace to avoid confusing users.
// See: SPARK-28340
case ce: ClosedByInterruptException =>
logError("Error occurred while fetching local blocks, " + ce.getMessage)
case ex: Exception => logError("Error occurred while fetching local blocks", ex)
}
results.put(new FailureFetchResult(blockId, mapIndex, blockManager.blockManagerId, e))
return
}
}
}
private[this] def fetchHostLocalBlock(
blockId: BlockId,
mapIndex: Int,
localDirs: Array[String],
blockManagerId: BlockManagerId): Boolean = {
try {
val buf = blockManager.getHostLocalShuffleData(blockId, localDirs)
buf.retain()
results.put(SuccessFetchResult(blockId, mapIndex, blockManagerId, buf.size(), buf,
isNetworkReqDone = false))
true
} catch {
case e: Exception =>
// If we see an exception, stop immediately.
logError(s"Error occurred while fetching local blocks", e)
results.put(FailureFetchResult(blockId, mapIndex, blockManagerId, e))
false
}
}
/**
* Fetch the host-local blocks while we are fetching remote blocks. This is ok because
* `ManagedBuffer`'s memory is allocated lazily when we create the input stream, so all we
* track in-memory are the ManagedBuffer references themselves.
*/
private[this] def fetchHostLocalBlocks(
hostLocalDirManager: HostLocalDirManager,
hostLocalBlocksByExecutor: mutable.LinkedHashMap[BlockManagerId, Seq[(BlockId, Long, Int)]]):
Unit = {
val cachedDirsByExec = hostLocalDirManager.getCachedHostLocalDirs
val (hostLocalBlocksWithCachedDirs, hostLocalBlocksWithMissingDirs) = {
val (hasCache, noCache) = hostLocalBlocksByExecutor.partition { case (hostLocalBmId, _) =>
cachedDirsByExec.contains(hostLocalBmId.executorId)
}
(hasCache.toMap, noCache.toMap)
}
if (hostLocalBlocksWithMissingDirs.nonEmpty) {
logDebug(s"Asynchronous fetching host-local blocks without cached executors' dir: " +
s"${hostLocalBlocksWithMissingDirs.mkString(", ")}")
// If the external shuffle service is enabled, we'll fetch the local directories for
// multiple executors from the external shuffle service, which located at the same host
// with the executors, in once. Otherwise, we'll fetch the local directories from those
// executors directly one by one. The fetch requests won't be too much since one host is
// almost impossible to have many executors at the same time practically.
val dirFetchRequests = if (blockManager.externalShuffleServiceEnabled) {
val host = blockManager.blockManagerId.host
val port = blockManager.externalShuffleServicePort
Seq((host, port, hostLocalBlocksWithMissingDirs.keys.toArray))
} else {
hostLocalBlocksWithMissingDirs.keys.map(bmId => (bmId.host, bmId.port, Array(bmId))).toSeq
}
dirFetchRequests.foreach { case (host, port, bmIds) =>
hostLocalDirManager.getHostLocalDirs(host, port, bmIds.map(_.executorId)) {
case Success(dirsByExecId) =>
fetchMultipleHostLocalBlocks(
hostLocalBlocksWithMissingDirs.filterKeys(bmIds.contains).toMap,
dirsByExecId,
cached = false)
case Failure(throwable) =>
logError("Error occurred while fetching host local blocks", throwable)
val bmId = bmIds.head
val blockInfoSeq = hostLocalBlocksWithMissingDirs(bmId)
val (blockId, _, mapIndex) = blockInfoSeq.head
results.put(FailureFetchResult(blockId, mapIndex, bmId, throwable))
}
}
}
if (hostLocalBlocksWithCachedDirs.nonEmpty) {
logDebug(s"Synchronous fetching host-local blocks with cached executors' dir: " +
s"${hostLocalBlocksWithCachedDirs.mkString(", ")}")
fetchMultipleHostLocalBlocks(hostLocalBlocksWithCachedDirs, cachedDirsByExec, cached = true)
}
}
private def fetchMultipleHostLocalBlocks(
bmIdToBlocks: Map[BlockManagerId, Seq[(BlockId, Long, Int)]],
localDirsByExecId: Map[String, Array[String]],
cached: Boolean): Unit = {
// We use `forall` because once there's a failed block fetch, `fetchHostLocalBlock` will put
// a `FailureFetchResult` immediately to the `results`. So there's no reason to fetch the
// remaining blocks.
val allFetchSucceeded = bmIdToBlocks.forall { case (bmId, blockInfos) =>
blockInfos.forall { case (blockId, _, mapIndex) =>
fetchHostLocalBlock(blockId, mapIndex, localDirsByExecId(bmId.executorId), bmId)
}
}
if (allFetchSucceeded) {
logDebug(s"Got host-local blocks from ${bmIdToBlocks.keys.mkString(", ")} " +
s"(${if (cached) "with" else "without"} cached executors' dir) " +
s"in ${Utils.getUsedTimeNs(startTimeNs)}")
}
}
private[this] def initialize(): Unit = {
// Add a task completion callback (called in both success case and failure case) to cleanup.
context.addTaskCompletionListener(onCompleteCallback)
// Local blocks to fetch, excluding zero-sized blocks.
val localBlocks = mutable.LinkedHashSet[(BlockId, Int)]()
val hostLocalBlocksByExecutor =
mutable.LinkedHashMap[BlockManagerId, Seq[(BlockId, Long, Int)]]()
val pushMergedLocalBlocks = mutable.LinkedHashSet[BlockId]()
// Partition blocks by the different fetch modes: local, host-local, push-merged-local and
// remote blocks.
val remoteRequests = partitionBlocksByFetchMode(
blocksByAddress, localBlocks, hostLocalBlocksByExecutor, pushMergedLocalBlocks)
// Add the remote requests into our queue in a random order
fetchRequests ++= Utils.randomize(remoteRequests)
assert ((0 == reqsInFlight) == (0 == bytesInFlight),
"expected reqsInFlight = 0 but found reqsInFlight = " + reqsInFlight +
", expected bytesInFlight = 0 but found bytesInFlight = " + bytesInFlight)
// Send out initial requests for blocks, up to our maxBytesInFlight
fetchUpToMaxBytes()
val numDeferredRequest = deferredFetchRequests.values.map(_.size).sum
val numFetches = remoteRequests.size - fetchRequests.size - numDeferredRequest
logInfo(s"Started $numFetches remote fetches in ${Utils.getUsedTimeNs(startTimeNs)}" +
(if (numDeferredRequest > 0 ) s", deferred $numDeferredRequest requests" else ""))
// Get Local Blocks
fetchLocalBlocks(localBlocks)
logDebug(s"Got local blocks in ${Utils.getUsedTimeNs(startTimeNs)}")
// Get host local blocks if any
fetchAllHostLocalBlocks(hostLocalBlocksByExecutor)
pushBasedFetchHelper.fetchAllPushMergedLocalBlocks(pushMergedLocalBlocks)
}
private def fetchAllHostLocalBlocks(
hostLocalBlocksByExecutor: mutable.LinkedHashMap[BlockManagerId, Seq[(BlockId, Long, Int)]]):
Unit = {
if (hostLocalBlocksByExecutor.nonEmpty) {
blockManager.hostLocalDirManager.foreach(fetchHostLocalBlocks(_, hostLocalBlocksByExecutor))
}
}
override def hasNext: Boolean = numBlocksProcessed < numBlocksToFetch
/**
* Fetches the next (BlockId, InputStream). If a task fails, the ManagedBuffers
* underlying each InputStream will be freed by the cleanup() method registered with the
* TaskCompletionListener. However, callers should close() these InputStreams
* as soon as they are no longer needed, in order to release memory as early as possible.
*
* Throws a FetchFailedException if the next block could not be fetched.
*/
override def next(): (BlockId, InputStream) = {
if (!hasNext) {
throw SparkCoreErrors.noSuchElementError()
}
numBlocksProcessed += 1
var result: FetchResult = null
var input: InputStream = null
// This's only initialized when shuffle checksum is enabled.
var checkedIn: CheckedInputStream = null
var streamCompressedOrEncrypted: Boolean = false
// Take the next fetched result and try to decompress it to detect data corruption,
// then fetch it one more time if it's corrupt, throw FailureFetchResult if the second fetch
// is also corrupt, so the previous stage could be retried.
// For local shuffle block, throw FailureFetchResult for the first IOException.
while (result == null) {
val startFetchWait = System.nanoTime()
result = results.take()
val fetchWaitTime = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startFetchWait)
shuffleMetrics.incFetchWaitTime(fetchWaitTime)
result match {
case r @ SuccessFetchResult(blockId, mapIndex, address, size, buf, isNetworkReqDone) =>
if (address != blockManager.blockManagerId) {
if (hostLocalBlocks.contains(blockId -> mapIndex) ||
pushBasedFetchHelper.isLocalPushMergedBlockAddress(address)) {
// It is a host local block or a local shuffle chunk
shuffleMetrics.incLocalBlocksFetched(1)
shuffleMetrics.incLocalBytesRead(buf.size)
} else {
numBlocksInFlightPerAddress(address) -= 1
shuffleMetrics.incRemoteBytesRead(buf.size)
if (buf.isInstanceOf[FileSegmentManagedBuffer]) {
shuffleMetrics.incRemoteBytesReadToDisk(buf.size)
}
shuffleMetrics.incRemoteBlocksFetched(1)
bytesInFlight -= size
}
}
if (isNetworkReqDone) {
reqsInFlight -= 1
resetNettyOOMFlagIfPossible(maxReqSizeShuffleToMem)
logDebug("Number of requests in flight " + reqsInFlight)
}
if (buf.size == 0) {
// We will never legitimately receive a zero-size block. All blocks with zero records
// have zero size and all zero-size blocks have no records (and hence should never
// have been requested in the first place). This statement relies on behaviors of the
// shuffle writers, which are guaranteed by the following test cases:
//
// - BypassMergeSortShuffleWriterSuite: "write with some empty partitions"
// - UnsafeShuffleWriterSuite: "writeEmptyIterator"
// - DiskBlockObjectWriterSuite: "commit() and close() without ever opening or writing"
//
// There is not an explicit test for SortShuffleWriter but the underlying APIs that
// uses are shared by the UnsafeShuffleWriter (both writers use DiskBlockObjectWriter
// which returns a zero-size from commitAndGet() in case no records were written
// since the last call.
val msg = s"Received a zero-size buffer for block $blockId from $address " +
s"(expectedApproxSize = $size, isNetworkReqDone=$isNetworkReqDone)"
throwFetchFailedException(blockId, mapIndex, address, new IOException(msg))
}
val in = try {
val bufIn = buf.createInputStream()
if (checksumEnabled) {
val checksum = ShuffleChecksumHelper.getChecksumByAlgorithm(checksumAlgorithm)
checkedIn = new CheckedInputStream(bufIn, checksum)
checkedIn
} else {
bufIn
}
} catch {
// The exception could only be throwed by local shuffle block
case e: IOException =>
assert(buf.isInstanceOf[FileSegmentManagedBuffer])
e match {
case ce: ClosedByInterruptException =>
logError("Failed to create input stream from local block, " +
ce.getMessage)
case e: IOException => logError("Failed to create input stream from local block", e)
}
buf.release()
if (blockId.isShuffleChunk) {
pushBasedFetchHelper.initiateFallbackFetchForPushMergedBlock(blockId, address)
// Set result to null to trigger another iteration of the while loop to get either.
result = null
null
} else {
throwFetchFailedException(blockId, mapIndex, address, e)
}
}
if (in != null) {
try {
input = streamWrapper(blockId, in)
// If the stream is compressed or wrapped, then we optionally decompress/unwrap the
// first maxBytesInFlight/3 bytes into memory, to check for corruption in that portion
// of the data. But even if 'detectCorruptUseExtraMemory' configuration is off, or if
// the corruption is later, we'll still detect the corruption later in the stream.
streamCompressedOrEncrypted = !input.eq(in)
if (streamCompressedOrEncrypted && detectCorruptUseExtraMemory) {
// TODO: manage the memory used here, and spill it into disk in case of OOM.
input = Utils.copyStreamUpTo(input, maxBytesInFlight / 3)
}
} catch {
case e: IOException =>
// When shuffle checksum is enabled, for a block that is corrupted twice,
// we'd calculate the checksum of the block by consuming the remaining data
// in the buf. So, we should release the buf later.
if (!(checksumEnabled && corruptedBlocks.contains(blockId))) {
buf.release()
}
if (blockId.isShuffleChunk) {
// TODO (SPARK-36284): Add shuffle checksum support for push-based shuffle
// Retrying a corrupt block may result again in a corrupt block. For shuffle
// chunks, we opt to fallback on the original shuffle blocks that belong to that
// corrupt shuffle chunk immediately instead of retrying to fetch the corrupt
// chunk. This also makes the code simpler because the chunkMeta corresponding to
// a shuffle chunk is always removed from chunksMetaMap whenever a shuffle chunk
// gets processed. If we try to re-fetch a corrupt shuffle chunk, then it has to
// be added back to the chunksMetaMap.
pushBasedFetchHelper.initiateFallbackFetchForPushMergedBlock(blockId, address)
// Set result to null to trigger another iteration of the while loop.
result = null
} else if (buf.isInstanceOf[FileSegmentManagedBuffer]) {
throwFetchFailedException(blockId, mapIndex, address, e)
} else if (corruptedBlocks.contains(blockId)) {
// It's the second time this block is detected corrupted
if (checksumEnabled) {
// Diagnose the cause of data corruption if shuffle checksum is enabled
val diagnosisResponse = diagnoseCorruption(checkedIn, address, blockId)
buf.release()
logError(diagnosisResponse)
throwFetchFailedException(
blockId, mapIndex, address, e, Some(diagnosisResponse))
} else {
throwFetchFailedException(blockId, mapIndex, address, e)
}
} else {
// It's the first time this block is detected corrupted
logWarning(s"got an corrupted block $blockId from $address, fetch again", e)
corruptedBlocks += blockId
fetchRequests += FetchRequest(
address, Array(FetchBlockInfo(blockId, size, mapIndex)))
result = null
}
} finally {
if (blockId.isShuffleChunk) {
pushBasedFetchHelper.removeChunk(blockId.asInstanceOf[ShuffleBlockChunkId])
}
// TODO: release the buf here to free memory earlier
if (input == null) {
// Close the underlying stream if there was an issue in wrapping the stream using
// streamWrapper
in.close()
}
}
}
case FailureFetchResult(blockId, mapIndex, address, e) =>
var errorMsg: String = null
if (e.isInstanceOf[OutOfDirectMemoryError]) {
errorMsg = s"Block $blockId fetch failed after $maxAttemptsOnNettyOOM " +
s"retries due to Netty OOM"
logError(errorMsg)
}
throwFetchFailedException(blockId, mapIndex, address, e, Some(errorMsg))
case DeferFetchRequestResult(request) =>
val address = request.address
numBlocksInFlightPerAddress(address) -= request.blocks.size
bytesInFlight -= request.size
reqsInFlight -= 1
logDebug("Number of requests in flight " + reqsInFlight)
val defReqQueue =
deferredFetchRequests.getOrElseUpdate(address, new Queue[FetchRequest]())
defReqQueue.enqueue(request)
result = null
case FallbackOnPushMergedFailureResult(blockId, address, size, isNetworkReqDone) =>
// We get this result in 3 cases:
// 1. Failure to fetch the data of a remote shuffle chunk. In this case, the
// blockId is a ShuffleBlockChunkId.
// 2. Failure to read the push-merged-local meta. In this case, the blockId is
// ShuffleBlockId.
// 3. Failure to get the push-merged-local directories from the external shuffle service.
// In this case, the blockId is ShuffleBlockId.
if (pushBasedFetchHelper.isRemotePushMergedBlockAddress(address)) {
numBlocksInFlightPerAddress(address) -= 1
bytesInFlight -= size
}
if (isNetworkReqDone) {
reqsInFlight -= 1
logDebug("Number of requests in flight " + reqsInFlight)
}
pushBasedFetchHelper.initiateFallbackFetchForPushMergedBlock(blockId, address)
// Set result to null to trigger another iteration of the while loop to get either
// a SuccessFetchResult or a FailureFetchResult.
result = null
case PushMergedLocalMetaFetchResult(
shuffleId, shuffleMergeId, reduceId, bitmaps, localDirs) =>
// Fetch push-merged-local shuffle block data as multiple shuffle chunks
val shuffleBlockId = ShuffleMergedBlockId(shuffleId, shuffleMergeId, reduceId)
try {
val bufs: Seq[ManagedBuffer] = blockManager.getLocalMergedBlockData(shuffleBlockId,
localDirs)
// Since the request for local block meta completed successfully, numBlocksToFetch
// is decremented.
numBlocksToFetch -= 1
// Update total number of blocks to fetch, reflecting the multiple local shuffle
// chunks.
numBlocksToFetch += bufs.size
bufs.zipWithIndex.foreach { case (buf, chunkId) =>
buf.retain()
val shuffleChunkId = ShuffleBlockChunkId(shuffleId, shuffleMergeId, reduceId,
chunkId)
pushBasedFetchHelper.addChunk(shuffleChunkId, bitmaps(chunkId))
results.put(SuccessFetchResult(shuffleChunkId, SHUFFLE_PUSH_MAP_ID,
pushBasedFetchHelper.localShuffleMergerBlockMgrId, buf.size(), buf,
isNetworkReqDone = false))
}
} catch {
case e: Exception =>
// If we see an exception with reading push-merged-local index file, we fallback
// to fetch the original blocks. We do not report block fetch failure
// and will continue with the remaining local block read.
logWarning(s"Error occurred while reading push-merged-local index, " +
s"prepare to fetch the original blocks", e)
pushBasedFetchHelper.initiateFallbackFetchForPushMergedBlock(
shuffleBlockId, pushBasedFetchHelper.localShuffleMergerBlockMgrId)
}
result = null
case PushMergedRemoteMetaFetchResult(
shuffleId, shuffleMergeId, reduceId, blockSize, bitmaps, address) =>
// The original meta request is processed so we decrease numBlocksToFetch and
// numBlocksInFlightPerAddress by 1. We will collect new shuffle chunks request and the
// count of this is added to numBlocksToFetch in collectFetchReqsFromMergedBlocks.
numBlocksInFlightPerAddress(address) -= 1
numBlocksToFetch -= 1
val blocksToFetch = pushBasedFetchHelper.createChunkBlockInfosFromMetaResponse(
shuffleId, shuffleMergeId, reduceId, blockSize, bitmaps)
val additionalRemoteReqs = new ArrayBuffer[FetchRequest]
collectFetchRequests(address, blocksToFetch.toSeq, additionalRemoteReqs)
fetchRequests ++= additionalRemoteReqs
// Set result to null to force another iteration.
result = null
case PushMergedRemoteMetaFailedFetchResult(
shuffleId, shuffleMergeId, reduceId, address) =>
// The original meta request failed so we decrease numBlocksInFlightPerAddress by 1.
numBlocksInFlightPerAddress(address) -= 1
// If we fail to fetch the meta of a push-merged block, we fall back to fetching the
// original blocks.
pushBasedFetchHelper.initiateFallbackFetchForPushMergedBlock(
ShuffleMergedBlockId(shuffleId, shuffleMergeId, reduceId), address)
// Set result to null to force another iteration.
result = null
}
// Send fetch requests up to maxBytesInFlight
fetchUpToMaxBytes()
}
currentResult = result.asInstanceOf[SuccessFetchResult]
(currentResult.blockId,
new BufferReleasingInputStream(
input,
this,
currentResult.blockId,
currentResult.mapIndex,
currentResult.address,
detectCorrupt && streamCompressedOrEncrypted,
currentResult.isNetworkReqDone,
Option(checkedIn)))
}
/**
* Get the suspect corruption cause for the corrupted block. It should be only invoked
* when checksum is enabled and corruption was detected at least once.
*
* This will firstly consume the rest of stream of the corrupted block to calculate the
* checksum of the block. Then, it will raise a synchronized RPC call along with the
* checksum to ask the server(where the corrupted block is fetched from) to diagnose the
* cause of corruption and return it.
*
* Any exception raised during the process will result in the [[Cause.UNKNOWN_ISSUE]] of the
* corruption cause since corruption diagnosis is only a best effort.
*
* @param checkedIn the [[CheckedInputStream]] which is used to calculate the checksum.
* @param address the address where the corrupted block is fetched from.
* @param blockId the blockId of the corrupted block.
* @return The corruption diagnosis response for different causes.
*/
private[storage] def diagnoseCorruption(
checkedIn: CheckedInputStream,
address: BlockManagerId,
blockId: BlockId): String = {
logInfo("Start corruption diagnosis.")
blockId match {
case shuffleBlock: ShuffleBlockId =>
val startTimeNs = System.nanoTime()
val buffer = new Array[Byte](ShuffleChecksumHelper.CHECKSUM_CALCULATION_BUFFER)
// consume the remaining data to calculate the checksum
var cause: Cause = null
try {
while (checkedIn.read(buffer) != -1) {}
val checksum = checkedIn.getChecksum.getValue
cause = shuffleClient.diagnoseCorruption(address.host, address.port, address.executorId,
shuffleBlock.shuffleId, shuffleBlock.mapId, shuffleBlock.reduceId, checksum,
checksumAlgorithm)
} catch {
case e: Exception =>
logWarning("Unable to diagnose the corruption cause of the corrupted block", e)
cause = Cause.UNKNOWN_ISSUE
}
val duration = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTimeNs)
val diagnosisResponse = cause match {
case Cause.UNSUPPORTED_CHECKSUM_ALGORITHM =>
s"Block $blockId is corrupted but corruption diagnosis failed due to " +
s"unsupported checksum algorithm: $checksumAlgorithm"
case Cause.CHECKSUM_VERIFY_PASS =>
s"Block $blockId is corrupted but checksum verification passed"
case Cause.UNKNOWN_ISSUE =>
s"Block $blockId is corrupted but the cause is unknown"
case otherCause =>
s"Block $blockId is corrupted due to $otherCause"
}
logInfo(s"Finished corruption diagnosis in $duration ms. $diagnosisResponse")
diagnosisResponse
case shuffleBlockChunk: ShuffleBlockChunkId =>
// TODO SPARK-36284 Add shuffle checksum support for push-based shuffle
val diagnosisResponse = s"BlockChunk $shuffleBlockChunk is corrupted but corruption " +
s"diagnosis is skipped due to lack of shuffle checksum support for push-based shuffle."
logWarning(diagnosisResponse)
diagnosisResponse
case unexpected: BlockId =>
throw new IllegalArgumentException(s"Unexpected type of BlockId, $unexpected")
}
}
def toCompletionIterator: Iterator[(BlockId, InputStream)] = {
CompletionIterator[(BlockId, InputStream), this.type](this,
onCompleteCallback.onComplete(context))
}
private def fetchUpToMaxBytes(): Unit = {
if (isNettyOOMOnShuffle.get()) {
if (reqsInFlight > 0) {
// Return immediately if Netty is still OOMed and there're ongoing fetch requests
return
} else {
resetNettyOOMFlagIfPossible(0)
}
}
// Send fetch requests up to maxBytesInFlight. If you cannot fetch from a remote host
// immediately, defer the request until the next time it can be processed.
// Process any outstanding deferred fetch requests if possible.
if (deferredFetchRequests.nonEmpty) {
for ((remoteAddress, defReqQueue) <- deferredFetchRequests) {
while (isRemoteBlockFetchable(defReqQueue) &&
!isRemoteAddressMaxedOut(remoteAddress, defReqQueue.front)) {
val request = defReqQueue.dequeue()
logDebug(s"Processing deferred fetch request for $remoteAddress with "
+ s"${request.blocks.length} blocks")
send(remoteAddress, request)
if (defReqQueue.isEmpty) {
deferredFetchRequests -= remoteAddress
}
}
}
}
// Process any regular fetch requests if possible.
while (isRemoteBlockFetchable(fetchRequests)) {
val request = fetchRequests.dequeue()
val remoteAddress = request.address
if (isRemoteAddressMaxedOut(remoteAddress, request)) {
logDebug(s"Deferring fetch request for $remoteAddress with ${request.blocks.size} blocks")
val defReqQueue = deferredFetchRequests.getOrElse(remoteAddress, new Queue[FetchRequest]())
defReqQueue.enqueue(request)
deferredFetchRequests(remoteAddress) = defReqQueue
} else {
send(remoteAddress, request)
}
}
def send(remoteAddress: BlockManagerId, request: FetchRequest): Unit = {
if (request.forMergedMetas) {
pushBasedFetchHelper.sendFetchMergedStatusRequest(request)
} else {
sendRequest(request)
}
numBlocksInFlightPerAddress(remoteAddress) =
numBlocksInFlightPerAddress.getOrElse(remoteAddress, 0) + request.blocks.size
}
def isRemoteBlockFetchable(fetchReqQueue: Queue[FetchRequest]): Boolean = {
fetchReqQueue.nonEmpty &&
(bytesInFlight == 0 ||
(reqsInFlight + 1 <= maxReqsInFlight &&
bytesInFlight + fetchReqQueue.front.size <= maxBytesInFlight))
}
// Checks if sending a new fetch request will exceed the max no. of blocks being fetched from a
// given remote address.
def isRemoteAddressMaxedOut(remoteAddress: BlockManagerId, request: FetchRequest): Boolean = {
numBlocksInFlightPerAddress.getOrElse(remoteAddress, 0) + request.blocks.size >
maxBlocksInFlightPerAddress
}
}
private[storage] def throwFetchFailedException(
blockId: BlockId,
mapIndex: Int,
address: BlockManagerId,
e: Throwable,
message: Option[String] = None) = {
val msg = message.getOrElse(e.getMessage)
blockId match {
case ShuffleBlockId(shufId, mapId, reduceId) =>
throw SparkCoreErrors.fetchFailedError(address, shufId, mapId, mapIndex, reduceId, msg, e)
case ShuffleBlockBatchId(shuffleId, mapId, startReduceId, _) =>
throw SparkCoreErrors.fetchFailedError(address, shuffleId, mapId, mapIndex, startReduceId,
msg, e)
case ShuffleBlockChunkId(shuffleId, _, reduceId, _) =>
throw SparkCoreErrors.fetchFailedError(address, shuffleId,
SHUFFLE_PUSH_MAP_ID.toLong, SHUFFLE_PUSH_MAP_ID, reduceId, msg, e)
case _ => throw SparkCoreErrors.failToGetNonShuffleBlockError(blockId, e)
}
}
/**
* All the below methods are used by [[PushBasedFetchHelper]] to communicate with the iterator
*/
private[storage] def addToResultsQueue(result: FetchResult): Unit = {
results.put(result)
}
private[storage] def decreaseNumBlocksToFetch(blocksFetched: Int): Unit = {
numBlocksToFetch -= blocksFetched
}
/**
* Currently used by [[PushBasedFetchHelper]] to fetch fallback blocks when there is a fetch
* failure related to a push-merged block or shuffle chunk.
* This is executed by the task thread when the `iterator.next()` is invoked and if that initiates
* fallback.
*/
private[storage] def fallbackFetch(
originalBlocksByAddr: Iterator[(BlockManagerId, Seq[(BlockId, Long, Int)])]): Unit = {
val originalLocalBlocks = mutable.LinkedHashSet[(BlockId, Int)]()
val originalHostLocalBlocksByExecutor =
mutable.LinkedHashMap[BlockManagerId, Seq[(BlockId, Long, Int)]]()
val originalMergedLocalBlocks = mutable.LinkedHashSet[BlockId]()
val originalRemoteReqs = partitionBlocksByFetchMode(originalBlocksByAddr,
originalLocalBlocks, originalHostLocalBlocksByExecutor, originalMergedLocalBlocks)
// Add the remote requests into our queue in a random order
fetchRequests ++= Utils.randomize(originalRemoteReqs)
logInfo(s"Created ${originalRemoteReqs.size} fallback remote requests for push-merged")
// fetch all the fallback blocks that are local.
fetchLocalBlocks(originalLocalBlocks)
// Merged local blocks should be empty during fallback
assert(originalMergedLocalBlocks.isEmpty,
"There should be zero push-merged blocks during fallback")
// Some of the fallback local blocks could be host local blocks
fetchAllHostLocalBlocks(originalHostLocalBlocksByExecutor)
}
/**
* Removes all the pending shuffle chunks that are on the same host and have the same reduceId as
* the current chunk that had a fetch failure.
* This is executed by the task thread when the `iterator.next()` is invoked and if that initiates
* fallback.
*
* @return set of all the removed shuffle chunk Ids.
*/
private[storage] def removePendingChunks(
failedBlockId: ShuffleBlockChunkId,
address: BlockManagerId): mutable.HashSet[ShuffleBlockChunkId] = {
val removedChunkIds = new mutable.HashSet[ShuffleBlockChunkId]()
def sameShuffleReducePartition(block: BlockId): Boolean = {
val chunkId = block.asInstanceOf[ShuffleBlockChunkId]
chunkId.shuffleId == failedBlockId.shuffleId && chunkId.reduceId == failedBlockId.reduceId
}
def filterRequests(queue: mutable.Queue[FetchRequest]): Unit = {
val fetchRequestsToRemove = new mutable.Queue[FetchRequest]()
fetchRequestsToRemove ++= queue.dequeueAll { req =>
val firstBlock = req.blocks.head
firstBlock.blockId.isShuffleChunk && req.address.equals(address) &&
sameShuffleReducePartition(firstBlock.blockId)
}
fetchRequestsToRemove.foreach { _ =>
removedChunkIds ++=
fetchRequestsToRemove.flatMap(_.blocks.map(_.blockId.asInstanceOf[ShuffleBlockChunkId]))
}
}
filterRequests(fetchRequests)
deferredFetchRequests.get(address).foreach { defRequests =>
filterRequests(defRequests)
if (defRequests.isEmpty) deferredFetchRequests.remove(address)
}
removedChunkIds
}
}
/**
* Helper class that ensures a ManagedBuffer is released upon InputStream.close() and
* also detects stream corruption if streamCompressedOrEncrypted is true
*/
private class BufferReleasingInputStream(
// This is visible for testing
private[storage] val delegate: InputStream,
private val iterator: ShuffleBlockFetcherIterator,
private val blockId: BlockId,
private val mapIndex: Int,
private val address: BlockManagerId,
private val detectCorruption: Boolean,
private val isNetworkReqDone: Boolean,
private val checkedInOpt: Option[CheckedInputStream])
extends InputStream {
private[this] var closed = false
override def read(): Int =
tryOrFetchFailedException(delegate.read())
override def close(): Unit = {
if (!closed) {
try {
delegate.close()
iterator.releaseCurrentResultBuffer()
} finally {
// Unset the flag when a remote request finished and free memory is fairly enough.
if (isNetworkReqDone) {
ShuffleBlockFetcherIterator.resetNettyOOMFlagIfPossible(iterator.maxReqSizeShuffleToMem)
}
closed = true
}
}
}
override def available(): Int = delegate.available()
override def mark(readlimit: Int): Unit = delegate.mark(readlimit)
override def skip(n: Long): Long =
tryOrFetchFailedException(delegate.skip(n))
override def markSupported(): Boolean = delegate.markSupported()
override def read(b: Array[Byte]): Int =
tryOrFetchFailedException(delegate.read(b))
override def read(b: Array[Byte], off: Int, len: Int): Int =
tryOrFetchFailedException(delegate.read(b, off, len))
override def reset(): Unit = delegate.reset()
/**
* Execute a block of code that returns a value, close this stream quietly and re-throwing
* IOException as FetchFailedException when detectCorruption is true. This method is only
* used by the `read` and `skip` methods inside `BufferReleasingInputStream` currently.
*/
private def tryOrFetchFailedException[T](block: => T): T = {
try {
block
} catch {
case e: IOException if detectCorruption =>
val diagnosisResponse = checkedInOpt.map { checkedIn =>
iterator.diagnoseCorruption(checkedIn, address, blockId)
}
IOUtils.closeQuietly(this)
// We'd never retry the block whatever the cause is since the block has been
// partially consumed by downstream RDDs.
iterator.throwFetchFailedException(blockId, mapIndex, address, e, diagnosisResponse)
}
}
}
/**
* A listener to be called at the completion of the ShuffleBlockFetcherIterator
* @param data the ShuffleBlockFetcherIterator to process
*/
private class ShuffleFetchCompletionListener(var data: ShuffleBlockFetcherIterator)
extends TaskCompletionListener {
override def onTaskCompletion(context: TaskContext): Unit = {
if (data != null) {
data.cleanup()
// Null out the referent here to make sure we don't keep a reference to this
// ShuffleBlockFetcherIterator, after we're done reading from it, to let it be
// collected during GC. Otherwise we can hold metadata on block locations(blocksByAddress)
data = null
}
}
// Just an alias for onTaskCompletion to avoid confusing
def onComplete(context: TaskContext): Unit = this.onTaskCompletion(context)
}
private[storage]
object ShuffleBlockFetcherIterator {
/**
* A flag which indicates whether the Netty OOM error has raised during shuffle.
* If true, unless there's no in-flight fetch requests, all the pending shuffle
* fetch requests will be deferred until the flag is unset (whenever there's a
* complete fetch request).
*/
val isNettyOOMOnShuffle = new AtomicBoolean(false)
def resetNettyOOMFlagIfPossible(freeMemoryLowerBound: Long): Unit = {
if (isNettyOOMOnShuffle.get() && NettyUtils.freeDirectMemory() >= freeMemoryLowerBound) {
isNettyOOMOnShuffle.compareAndSet(true, false)
}
}
/**
* This function is used to merged blocks when doBatchFetch is true. Blocks which have the
* same `mapId` can be merged into one block batch. The block batch is specified by a range
* of reduceId, which implies the continuous shuffle blocks that we can fetch in a batch.
* For example, input blocks like (shuffle_0_0_0, shuffle_0_0_1, shuffle_0_1_0) can be
* merged into (shuffle_0_0_0_2, shuffle_0_1_0_1), and input blocks like (shuffle_0_0_0_2,
* shuffle_0_0_2, shuffle_0_0_3) can be merged into (shuffle_0_0_0_4).
*
* @param blocks blocks to be merged if possible. May contains already merged blocks.
* @param doBatchFetch whether to merge blocks.
* @return the input blocks if doBatchFetch=false, or the merged blocks if doBatchFetch=true.
*/
def mergeContinuousShuffleBlockIdsIfNeeded(
blocks: Seq[FetchBlockInfo],
doBatchFetch: Boolean): Seq[FetchBlockInfo] = {
val result = if (doBatchFetch) {
val curBlocks = new ArrayBuffer[FetchBlockInfo]
val mergedBlockInfo = new ArrayBuffer[FetchBlockInfo]
def mergeFetchBlockInfo(toBeMerged: ArrayBuffer[FetchBlockInfo]): FetchBlockInfo = {
val startBlockId = toBeMerged.head.blockId.asInstanceOf[ShuffleBlockId]
// The last merged block may comes from the input, and we can merge more blocks
// into it, if the map id is the same.
def shouldMergeIntoPreviousBatchBlockId =
mergedBlockInfo.last.blockId.asInstanceOf[ShuffleBlockBatchId].mapId == startBlockId.mapId
val (startReduceId, size) =
if (mergedBlockInfo.nonEmpty && shouldMergeIntoPreviousBatchBlockId) {
// Remove the previous batch block id as we will add a new one to replace it.
val removed = mergedBlockInfo.remove(mergedBlockInfo.length - 1)
(removed.blockId.asInstanceOf[ShuffleBlockBatchId].startReduceId,
removed.size + toBeMerged.map(_.size).sum)
} else {
(startBlockId.reduceId, toBeMerged.map(_.size).sum)
}
FetchBlockInfo(
ShuffleBlockBatchId(
startBlockId.shuffleId,
startBlockId.mapId,
startReduceId,
toBeMerged.last.blockId.asInstanceOf[ShuffleBlockId].reduceId + 1),
size,
toBeMerged.head.mapIndex)
}
val iter = blocks.iterator
while (iter.hasNext) {
val info = iter.next()
// It's possible that the input block id is already a batch ID. For example, we merge some
// blocks, and then make fetch requests with the merged blocks according to "max blocks per
// request". The last fetch request may be too small, and we give up and put the remaining
// merged blocks back to the input list.
if (info.blockId.isInstanceOf[ShuffleBlockBatchId]) {
mergedBlockInfo += info
} else {
if (curBlocks.isEmpty) {
curBlocks += info
} else {
val curBlockId = info.blockId.asInstanceOf[ShuffleBlockId]
val currentMapId = curBlocks.head.blockId.asInstanceOf[ShuffleBlockId].mapId
if (curBlockId.mapId != currentMapId) {
mergedBlockInfo += mergeFetchBlockInfo(curBlocks)
curBlocks.clear()
}
curBlocks += info
}
}
}
if (curBlocks.nonEmpty) {
mergedBlockInfo += mergeFetchBlockInfo(curBlocks)
}
mergedBlockInfo
} else {
blocks
}
result.toSeq
}
/**
* The block information to fetch used in FetchRequest.
* @param blockId block id
* @param size estimated size of the block. Note that this is NOT the exact bytes.
* Size of remote block is used to calculate bytesInFlight.
* @param mapIndex the mapIndex for this block, which indicate the index in the map stage.
*/
private[storage] case class FetchBlockInfo(
blockId: BlockId,
size: Long,
mapIndex: Int)
/**
* A request to fetch blocks from a remote BlockManager.
* @param address remote BlockManager to fetch from.
* @param blocks Sequence of the information for blocks to fetch from the same address.
* @param forMergedMetas true if this request is for requesting push-merged meta information;
* false if it is for regular or shuffle chunks.
*/
case class FetchRequest(
address: BlockManagerId,
blocks: Seq[FetchBlockInfo],
forMergedMetas: Boolean = false) {
val size = blocks.map(_.size).sum
}
/**
* Result of a fetch from a remote block.
*/
private[storage] sealed trait FetchResult
/**
* Result of a fetch from a remote block successfully.
* @param blockId block id
* @param mapIndex the mapIndex for this block, which indicate the index in the map stage.
* @param address BlockManager that the block was fetched from.
* @param size estimated size of the block. Note that this is NOT the exact bytes.
* Size of remote block is used to calculate bytesInFlight.
* @param buf `ManagedBuffer` for the content.
* @param isNetworkReqDone Is this the last network request for this host in this fetch request.
*/
private[storage] case class SuccessFetchResult(
blockId: BlockId,
mapIndex: Int,
address: BlockManagerId,
size: Long,
buf: ManagedBuffer,
isNetworkReqDone: Boolean) extends FetchResult {
require(buf != null)
require(size >= 0)
}
/**
* Result of a fetch from a remote block unsuccessfully.
* @param blockId block id
* @param mapIndex the mapIndex for this block, which indicate the index in the map stage
* @param address BlockManager that the block was attempted to be fetched from
* @param e the failure exception
*/
private[storage] case class FailureFetchResult(
blockId: BlockId,
mapIndex: Int,
address: BlockManagerId,
e: Throwable)
extends FetchResult
/**
* Result of a fetch request that should be deferred for some reasons, e.g., Netty OOM
*/
private[storage]
case class DeferFetchRequestResult(fetchRequest: FetchRequest) extends FetchResult
/**
* Result of an un-successful fetch of either of these:
* 1) Remote shuffle chunk.
* 2) Local push-merged block.
*
* Instead of treating this as a [[FailureFetchResult]], we fallback to fetch the original blocks.
*
* @param blockId block id
* @param address BlockManager that the push-merged block was attempted to be fetched from
* @param size size of the block, used to update bytesInFlight.
* @param isNetworkReqDone Is this the last network request for this host in this fetch
* request. Used to update reqsInFlight.
*/
private[storage] case class FallbackOnPushMergedFailureResult(blockId: BlockId,
address: BlockManagerId,
size: Long,
isNetworkReqDone: Boolean) extends FetchResult
/**
* Result of a successful fetch of meta information for a remote push-merged block.
*
* @param shuffleId shuffle id.
* @param shuffleMergeId shuffleMergeId is used to uniquely identify merging process
* of shuffle by an indeterminate stage attempt.
* @param reduceId reduce id.
* @param blockSize size of each push-merged block.
* @param bitmaps bitmaps for every chunk.
* @param address BlockManager that the meta was fetched from.
*/
private[storage] case class PushMergedRemoteMetaFetchResult(
shuffleId: Int,
shuffleMergeId: Int,
reduceId: Int,
blockSize: Long,
bitmaps: Array[RoaringBitmap],
address: BlockManagerId) extends FetchResult
/**
* Result of a failure while fetching the meta information for a remote push-merged block.
*
* @param shuffleId shuffle id.
* @param shuffleMergeId shuffleMergeId is used to uniquely identify merging process
* of shuffle by an indeterminate stage attempt.
* @param reduceId reduce id.
* @param address BlockManager that the meta was fetched from.
*/
private[storage] case class PushMergedRemoteMetaFailedFetchResult(
shuffleId: Int,
shuffleMergeId: Int,
reduceId: Int,
address: BlockManagerId) extends FetchResult
/**
* Result of a successful fetch of meta information for a push-merged-local block.
*
* @param shuffleId shuffle id.
* @param shuffleMergeId shuffleMergeId is used to uniquely identify merging process
* of shuffle by an indeterminate stage attempt.
* @param reduceId reduce id.
* @param bitmaps bitmaps for every chunk.
* @param localDirs local directories where the push-merged shuffle files are storedl
*/
private[storage] case class PushMergedLocalMetaFetchResult(
shuffleId: Int,
shuffleMergeId: Int,
reduceId: Int,
bitmaps: Array[RoaringBitmap],
localDirs: Array[String]) extends FetchResult
}
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