otterc commented on a change in pull request #32140: URL: https://github.com/apache/spark/pull/32140#discussion_r655045176
########## File path: core/src/main/scala/org/apache/spark/storage/PushBasedFetchHelper.scala ########## @@ -0,0 +1,336 @@ +/* + * 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.{ConcurrentHashMap, 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. This is a concurrent hashmap because it + * can be modified by both the task thread and the netty thread. + */ + private[this] val chunksMetaMap = new ConcurrentHashMap[ShuffleBlockChunkId, RoaringBitmap]() + + /** + * Returns true if the address is for a push-merged block. + */ + def isMergedShuffleBlockAddress(address: BlockManagerId): Boolean = { + SHUFFLE_MERGER_IDENTIFIER == address.executorId + } + + /** + * Returns true if the address is of a remote merged block. + */ + def isMergedBlockAddressRemote(address: BlockManagerId): Boolean = { + assert(isMergedShuffleBlockAddress(address)) + address.host != blockManager.blockManagerId.host + } + + /** + * Returns true if the address if of merged local block. false otherwise. + */ + def isMergedLocal(address: BlockManagerId): Boolean = { + isMergedShuffleBlockAddress(address) && address.host == blockManager.blockManagerId.host + } + + /** + * This is executed by the task thread when the `iterator.next()` is invoked and the iterator + * processes a response of type [[ShuffleBlockFetcherIterator.SuccessFetchResult]]. + * + * @param blockId shuffle block chunk id. + */ + def getNumberOfBlocksInChunk(blockId : ShuffleBlockChunkId): Int = { + chunksMetaMap.get(blockId).getCardinality + } + + /** + * This is executed by the task thread when the `iterator.next()` is invoked and the iterator + * processes a response of type [[ShuffleBlockFetcherIterator.SuccessFetchResult]]. + * + * @param blockId shuffle block chunk id. + */ + def removeChunk(blockId: ShuffleBlockChunkId): Unit = { + chunksMetaMap.remove(blockId) + } + + /** + * This is executed by the task thread when the `iterator.next()` is invoked and the iterator + * processes a response of type [[ShuffleBlockFetcherIterator.MergedMetaFetchResult]]. + * + * @param shuffleId shuffle id. + * @param reduceId reduce id. + * @param blockSize size of the merged block. + * @param numChunks number of chunks in the merged block. + * @param bitmaps per chunk bitmap, where each bitmap contains all the mapIds that are merged + * to that chunk. + * @return shuffle chunks to fetch. + */ + 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 $approxChunkSize") + blocksToFetch += ((blockChunkId, approxChunkSize, SHUFFLE_PUSH_MAP_ID)) + } + blocksToFetch + } + + /** + * This is executed by the task thread when the iterator is initialized and only if it has + * push-merged blocks for which it needs to fetch the metadata. + * + * @param req [[ShuffleBlockFetcherIterator.FetchRequest]] that only contains requests to fetch + * metadata of merged blocks. + */ + def sendFetchMergedStatusRequest(req: FetchRequest): Unit = { + val sizeMap = req.blocks.map { + case FetchBlockInfo(blockId, size, _) => + val shuffleBlockId = blockId.asInstanceOf[ShuffleBlockId] + ((shuffleBlockId.shuffleId, shuffleBlockId.reduceId), size) + }.toMap + val address = req.address + val mergedBlocksMetaListener = new MergedBlocksMetaListener { + override def onSuccess(shuffleId: Int, reduceId: Int, meta: MergedBlockMeta): Unit = { + logInfo(s"Received the meta of merged block for ($shuffleId, $reduceId) " + + s"from ${req.address.host}:${req.address.port}") + try { + iterator.addToResultsQueue(MergedMetaFetchResult(shuffleId, reduceId, + sizeMap((shuffleId, reduceId)), meta.getNumChunks, meta.readChunkBitmaps(), address)) + } catch { + case exception: Exception => + logError(s"Failed to parse the meta of merged block for ($shuffleId, $reduceId) " + + s"from ${req.address.host}:${req.address.port}", exception) + iterator.addToResultsQueue( + MergedMetaFailedFetchResult(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(MergedMetaFailedFetchResult(shuffleId, reduceId, address)) + } + } + req.blocks.foreach { block => + val shuffleBlockId = block.blockId.asInstanceOf[ShuffleBlockId] + shuffleClient.getMergedBlockMeta(address.host, address.port, shuffleBlockId.shuffleId, + shuffleBlockId.reduceId, mergedBlocksMetaListener) + } + } + + /** + * This is executed by the task thread when the iterator is initialized. It fetches all the + * outstanding merged local blocks. + * @param mergedLocalBlocks set of identified 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(FallbackOnMergedFailureFetchResult( + blockId, localShuffleMergerBlockMgrId, 0, isNetworkReqDone = false)) + ) + } + } + } + + /** + * Fetch a single local merged block generated. This can also be executed by the task thread as + * well as the netty thread. + * @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.getLocalMergedBlockMeta(shuffleBlockId, localDirs) + .readChunkBitmaps() + // Fetch local merged shuffle block data as multiple chunks + val bufs: Seq[ManagedBuffer] = blockManager.getLocalMergedBlockData(shuffleBlockId, localDirs) + // Update total number of blocks to fetch, reflecting the multiple local chunks + iterator.incrementNumBlocksToFetch(bufs.size - 1) + for (chunkId <- bufs.indices) { + val buf = bufs(chunkId) + buf.retain() + val shuffleChunkId = ShuffleBlockChunkId(shuffleBlockId.shuffleId, + shuffleBlockId.reduceId, chunkId) + chunksMetaMap.put(shuffleChunkId, chunksMeta(chunkId)) + iterator.addToResultsQueue( + SuccessFetchResult(shuffleChunkId, SHUFFLE_PUSH_MAP_ID, blockManagerId, buf.size(), buf, + isNetworkReqDone = false)) + } + 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( + FallbackOnMergedFailureFetchResult(blockId, blockManagerId, 0, isNetworkReqDone = false)) + false + } + } + + /** + * This is executed by the task thread when the `iterator.next()` is invoked and the iterator + * processes a response of type: + * 1) [[ShuffleBlockFetcherIterator.SuccessFetchResult]] + * 2) [[ShuffleBlockFetcherIterator.FallbackOnMergedFailureFetchResult]] + * 3) [[ShuffleBlockFetcherIterator.MergedMetaFailedFetchResult]] + * + * This initiates fetching fallback blocks for a merged block (or a merged block chunk) that + * failed to fetch. + * It makes a call to the 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 = { + assert(blockId.isInstanceOf[ShuffleBlockId] || blockId.isInstanceOf[ShuffleBlockChunkId]) + 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)])] = + blockId match { + case shuffleBlockId: ShuffleBlockId => + mapOutputTracker.getMapSizesForMergeResult( + shuffleBlockId.shuffleId, shuffleBlockId.reduceId) + case _ => + val shuffleChunkId = blockId.asInstanceOf[ShuffleBlockChunkId] + val chunkBitmap: RoaringBitmap = chunksMetaMap.remove(shuffleChunkId) + assert(chunkBitmap != null) + // 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 (isMergedBlockAddressRemote(address)) { + // Fallback for all the pending fetch requests + val pendingShuffleChunks = iterator.removePendingChunks(shuffleChunkId, address) + if (pendingShuffleChunks.nonEmpty) { + pendingShuffleChunks.foreach { pendingBlockId => + logInfo(s"Falling back immediately for merged block $pendingBlockId") + val bitmapOfPendingChunk: RoaringBitmap = chunksMetaMap.remove(pendingBlockId) + assert(bitmapOfPendingChunk != null) + chunkBitmap.or(bitmapOfPendingChunk) + } + // These blocks were added to numBlocksToFetch so we increment numBlocksProcessed + blocksProcessed += pendingShuffleChunks.size + } + } + mapOutputTracker.getMapSizesForMergeResult( + shuffleChunkId.shuffleId, shuffleChunkId.reduceId, chunkBitmap) + } + iterator.fetchFallbackBlocks(fallbackBlocksByAddr) Review comment: done -- This is an automated message from the Apache Git Service. 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