otterc commented on a change in pull request #32140: URL: https://github.com/apache/spark/pull/32140#discussion_r649472914
########## File path: core/src/main/scala/org/apache/spark/storage/PushBasedFetchHelper.scala ########## @@ -0,0 +1,289 @@ +/* + * 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.storage + +import java.util.concurrent.TimeUnit + +import scala.collection.mutable +import scala.collection.mutable.ArrayBuffer +import scala.util.{Failure, Success} + +import org.roaringbitmap.RoaringBitmap + +import org.apache.spark.MapOutputTracker +import org.apache.spark.MapOutputTracker.SHUFFLE_PUSH_MAP_ID +import org.apache.spark.internal.Logging +import org.apache.spark.network.buffer.ManagedBuffer +import org.apache.spark.network.shuffle.{BlockStoreClient, MergedBlockMeta, MergedBlocksMetaListener} +import org.apache.spark.storage.BlockManagerId.SHUFFLE_MERGER_IDENTIFIER +import org.apache.spark.storage.ShuffleBlockFetcherIterator._ + +/** + * Helper class for [[ShuffleBlockFetcherIterator]] that encapsulates all the push-based + * functionality to fetch merged block meta and merged shuffle block chunks. + */ +private class PushBasedFetchHelper( + private val iterator: ShuffleBlockFetcherIterator, + private val shuffleClient: BlockStoreClient, + private val blockManager: BlockManager, + private val mapOutputTracker: MapOutputTracker) extends Logging { + + private[this] val startTimeNs = System.nanoTime() + + private[this] val localShuffleMergerBlockMgrId = BlockManagerId( + SHUFFLE_MERGER_IDENTIFIER, blockManager.blockManagerId.host, + blockManager.blockManagerId.port, blockManager.blockManagerId.topologyInfo) + + /** A map for storing merged block shuffle chunk bitmap */ + private[this] val chunksMetaMap = new mutable.HashMap[ShuffleBlockChunkId, RoaringBitmap]() + + /** + * Returns true if the address is for a push-merged block. + */ + def isMergedShuffleBlockAddress(address: BlockManagerId): Boolean = { + SHUFFLE_MERGER_IDENTIFIER.equals(address.executorId) + } + + /** + * Returns true if the address is not of executor local or merged local block. false otherwise. + */ + def isNotExecutorOrMergedLocal(address: BlockManagerId): Boolean = { + (isMergedShuffleBlockAddress(address) && address.host != blockManager.blockManagerId.host) || + (!isMergedShuffleBlockAddress(address) && address != blockManager.blockManagerId) + } + + /** + * Returns true if the address if of merged local block. false otherwise. + */ + def isMergedLocal(address: BlockManagerId): Boolean = { + isMergedShuffleBlockAddress(address) && address.host == blockManager.blockManagerId.host + } + + def getNumberOfBlocksInChunk(blockId : ShuffleBlockChunkId): Int = { + chunksMetaMap(blockId).getCardinality + } + + def removeChunk(blockId: ShuffleBlockChunkId): Unit = { + chunksMetaMap.remove(blockId) + } + + def createChunkBlockInfosFromMetaResponse( + shuffleId: Int, + reduceId: Int, + blockSize: Long, + numChunks: Int, + bitmaps: Array[RoaringBitmap]): ArrayBuffer[(BlockId, Long, Int)] = { + val approxChunkSize = blockSize / numChunks + val blocksToFetch = new ArrayBuffer[(BlockId, Long, Int)]() + for (i <- 0 until numChunks) { + val blockChunkId = ShuffleBlockChunkId(shuffleId, reduceId, i) + chunksMetaMap.put(blockChunkId, bitmaps(i)) + logDebug(s"adding block chunk $blockChunkId of size $approxChunkSize") + blocksToFetch += ((blockChunkId, approxChunkSize, SHUFFLE_PUSH_MAP_ID)) + } + blocksToFetch + } + + def sendFetchMergedStatusRequest(req: FetchRequest): Unit = { + val sizeMap = req.blocks.map { + case FetchBlockInfo(blockId, size, _) => + val shuffleBlockId = blockId.asInstanceOf[ShuffleBlockId] + ((shuffleBlockId.shuffleId, shuffleBlockId.reduceId), size)}.toMap + val address = req.address + val mergedBlocksMetaListener = new MergedBlocksMetaListener { + override def onSuccess(shuffleId: Int, reduceId: Int, meta: MergedBlockMeta): Unit = { + logInfo(s"Received the meta of merged block for ($shuffleId, $reduceId) " + + s"from ${req.address.host}:${req.address.port}") + try { + iterator.addToResultsQueue(MergedBlocksMetaFetchResult(shuffleId, reduceId, + sizeMap((shuffleId, reduceId)), meta.getNumChunks, meta.readChunkBitmaps(), address)) + } catch { + case exception: Throwable => + logError(s"Failed to parse the meta of merged block for ($shuffleId, $reduceId) " + + s"from ${req.address.host}:${req.address.port}", exception) + iterator.addToResultsQueue( + MergedBlocksMetaFailedFetchResult(shuffleId, reduceId, address)) + } + } + + override def onFailure(shuffleId: Int, reduceId: Int, exception: Throwable): Unit = { + logError(s"Failed to get the meta of merged block for ($shuffleId, $reduceId) " + + s"from ${req.address.host}:${req.address.port}", exception) + iterator.addToResultsQueue(MergedBlocksMetaFailedFetchResult(shuffleId, reduceId, address)) + } + } + req.blocks.foreach { block => + val shuffleBlockId = block.blockId.asInstanceOf[ShuffleBlockId] + shuffleClient.getMergedBlockMeta(address.host, address.port, shuffleBlockId.shuffleId, + shuffleBlockId.reduceId, mergedBlocksMetaListener) + } + } + + // Fetch all outstanding merged local blocks + def fetchAllMergedLocalBlocks( + mergedLocalBlocks: mutable.LinkedHashSet[BlockId]): Unit = { + if (mergedLocalBlocks.nonEmpty) { + blockManager.hostLocalDirManager.foreach(fetchMergedLocalBlocks(_, mergedLocalBlocks)) + } + } + + /** + * Fetch the merged blocks dirs if they are not in the cache and eventually fetch merged local + * blocks. + */ + private def fetchMergedLocalBlocks( + hostLocalDirManager: HostLocalDirManager, + mergedLocalBlocks: mutable.LinkedHashSet[BlockId]): Unit = { + val cachedMergerDirs = hostLocalDirManager.getCachedHostLocalDirs.get( + SHUFFLE_MERGER_IDENTIFIER) + if (cachedMergerDirs.isDefined) { + logDebug(s"Fetching local merged blocks with cached executors dir: " + + s"${cachedMergerDirs.get.mkString(", ")}") + mergedLocalBlocks.foreach(blockId => + fetchMergedLocalBlock(blockId, cachedMergerDirs.get, localShuffleMergerBlockMgrId)) + } else { + logDebug(s"Asynchronous fetching local merged blocks without cached executors dir") + hostLocalDirManager.getHostLocalDirs(localShuffleMergerBlockMgrId.host, + localShuffleMergerBlockMgrId.port, Array(SHUFFLE_MERGER_IDENTIFIER)) { + case Success(dirs) => + mergedLocalBlocks.takeWhile { + blockId => + logDebug(s"Successfully fetched local dirs: " + + s"${dirs.get(SHUFFLE_MERGER_IDENTIFIER).mkString(", ")}") + fetchMergedLocalBlock(blockId, dirs(SHUFFLE_MERGER_IDENTIFIER), + localShuffleMergerBlockMgrId) + } + logDebug(s"Got local merged blocks (without cached executors' dir) in " + + s"${TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTimeNs)} ms") + case Failure(throwable) => + // If we see an exception with getting the local dirs for local merged blocks, + // we fallback to fetch the original unmerged blocks. We do not report block fetch + // failure. + logWarning(s"Error occurred while getting the local dirs for local merged " + + s"blocks: ${mergedLocalBlocks.mkString(", ")}. Fetch the original blocks instead", + throwable) + mergedLocalBlocks.foreach( + blockId => iterator.addToResultsQueue( + IgnoreFetchResult(blockId, localShuffleMergerBlockMgrId, 0, isNetworkReqDone = false)) + ) + } + } + } + + /** + * Fetch a single local merged block generated. + * @param blockId ShuffleBlockId to be fetched + * @param localDirs Local directories where the merged shuffle files are stored + * @param blockManagerId BlockManagerId + * @return Boolean represents successful or failed fetch + */ + private[this] def fetchMergedLocalBlock( + blockId: BlockId, + localDirs: Array[String], + blockManagerId: BlockManagerId): Boolean = { + try { + val shuffleBlockId = blockId.asInstanceOf[ShuffleBlockId] + val chunksMeta = blockManager.getMergedBlockMeta(shuffleBlockId, localDirs) + .readChunkBitmaps() + // Fetch local merged shuffle block data as multiple chunks + val bufs: Seq[ManagedBuffer] = blockManager.getMergedBlockData(shuffleBlockId, localDirs) + // Update total number of blocks to fetch, reflecting the multiple local chunks + iterator.foundMoreBlocksToFetch(bufs.size - 1) + for (chunkId <- bufs.indices) { + val buf = bufs(chunkId) + buf.retain() + val shuffleChunkId = ShuffleBlockChunkId(shuffleBlockId.shuffleId, + shuffleBlockId.reduceId, chunkId) + iterator.addToResultsQueue( + SuccessFetchResult(shuffleChunkId, SHUFFLE_PUSH_MAP_ID, blockManagerId, buf.size(), buf, + isNetworkReqDone = false)) + chunksMetaMap.put(shuffleChunkId, chunksMeta(chunkId)) + } + true + } catch { + case e: Exception => + // If we see an exception with reading a local merged block, we fallback to + // fetch the original unmerged blocks. We do not report block fetch failure + // and will continue with the remaining local block read. + logWarning(s"Error occurred while fetching local merged block, " + + s"prepare to fetch the original blocks", e) + iterator.addToResultsQueue( + IgnoreFetchResult(blockId, blockManagerId, 0, isNetworkReqDone = false)) + false + } + } + + /** + * Initiate fetching fallback blocks for a merged block (or a merged block chunk) that's failed + * to fetch. + * It calls out to map output tracker to get the list of original blocks for the + * given merged blocks, split them into remote and local blocks, and process them + * accordingly. + * The fallback happens when: + * 1. There is an exception while creating shuffle block chunk from local merged shuffle block. + * See fetchLocalBlock. + * 2. There is a failure when fetching remote shuffle block chunks. + * 3. There is a failure when processing SuccessFetchResult which is for a shuffle chunk + * (local or remote). + * + * @return number of blocks processed + */ + def initiateFallbackBlockFetchForMergedBlock( + blockId: BlockId, + address: BlockManagerId): Int = { + logWarning(s"Falling back to fetch the original unmerged blocks for merged block $blockId") + // Increase the blocks processed since we will process another block in the next iteration of + // the while loop in ShuffleBlockFetcherIterator.next(). + var blocksProcessed = 1 + val fallbackBlocksByAddr: Iterator[(BlockManagerId, Seq[(BlockId, Long, Int)])] = + if (blockId.isShuffle) { + val shuffleBlockId = blockId.asInstanceOf[ShuffleBlockId] + mapOutputTracker.getMapSizesForMergeResult( + shuffleBlockId.shuffleId, shuffleBlockId.reduceId) + } else { + val shuffleChunkId = blockId.asInstanceOf[ShuffleBlockChunkId] + val chunkBitmap: RoaringBitmap = chunksMetaMap.remove(shuffleChunkId).orNull + // When there is a failure to fetch a remote merged shuffle block chunk, then we try to + // fallback not only for that particular remote shuffle block chunk but also for all the + // pending block chunks that belong to the same host. The reason for doing so is that it is + // very likely that the subsequent requests for merged block chunks from this host will fail + // as well. Since, push-based shuffle is best effort and we try not to increase the delay + // of the fetches, we immediately fallback for all the pending shuffle chunks in the + // fetchRequests queue. + if (isNotExecutorOrMergedLocal(address)) { + // Fallback for all the pending fetch requests + val pendingShuffleChunks = iterator.removePendingChunks(shuffleChunkId, address) + if (pendingShuffleChunks.nonEmpty) { + pendingShuffleChunks.foreach { pendingBlockId => + logWarning(s"Falling back immediately for merged block $pendingBlockId") + val bitmapOfPendingChunk: RoaringBitmap = + chunksMetaMap.remove(pendingBlockId).orNull + assert(bitmapOfPendingChunk != null) + chunkBitmap.or(bitmapOfPendingChunk) Review comment: `chunkBitmap` should not be `null`. I think the code is missing that assertion currently which I will add. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
