otterc commented on a change in pull request #32140:
URL: https://github.com/apache/spark/pull/32140#discussion_r648685526
##########
File path:
core/src/main/scala/org/apache/spark/storage/ShuffleBlockFetcherIterator.scala
##########
@@ -1124,4 +1392,298 @@ object ShuffleBlockFetcherIterator {
*/
private[storage]
case class DeferFetchRequestResult(fetchRequest: FetchRequest) extends
FetchResult
+
+ /**
+ * Result of a fetch from a remote merged block unsuccessfully.
+ * Instead of treating this as a FailureFetchResult, we ignore this failure
+ * and fallback to fetch the original unmerged blocks.
+ * @param blockId block id
+ * @param address BlockManager that the 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 IgnoreFetchResult(blockId: BlockId,
+ address: BlockManagerId,
+ size: Long,
+ isNetworkReqDone: Boolean) extends FetchResult
+
+ /**
+ * Result of a successful fetch of meta information for a merged block.
+ *
+ * @param shuffleId shuffle id.
+ * @param reduceId reduce id.
+ * @param blockSize size of each merged block.
+ * @param numChunks number of chunks in the merged block.
+ * @param bitmaps bitmaps for every chunk.
+ * @param address BlockManager that the merged status was fetched
from.
+ */
+ private[storage] case class MergedBlocksMetaFetchResult(
+ shuffleId: Int,
+ reduceId: Int,
+ blockSize: Long,
+ numChunks: Int,
+ bitmaps: Array[RoaringBitmap],
+ address: BlockManagerId,
+ blockId: BlockId = DUMMY_SHUFFLE_BLOCK_ID) extends FetchResult
+
+ /**
+ * Result of a failure while fetching the meta information for a merged
block.
+ *
+ * @param shuffleId shuffle id.
+ * @param reduceId reduce id.
+ * @param address BlockManager that the merged status was fetched from.
+ */
+ private[storage] case class MergedBlocksMetaFailedFetchResult(
+ shuffleId: Int,
+ reduceId: Int,
+ address: BlockManagerId,
+ blockId: BlockId = DUMMY_SHUFFLE_BLOCK_ID) extends FetchResult
+}
+
+/**
+ * Helper class 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 blocksToRequest: ArrayBuffer[(BlockId, Long, Int)] =
+ 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 $approxChunkSize")
+ blocksToRequest += ((blockChunkId, approxChunkSize, SHUFFLE_PUSH_MAP_ID))
+ }
+ blocksToRequest
+ }
+
+ def sendFetchMergedStatusRequest(req: FetchRequest): Unit = {
+ val sizeMap = req.blocks.map {
+ case FetchBlockInfo(blockId, size, _) =>
+ val shuffleBlockId = blockId.asInstanceOf[ShuffleBlockId]
+ ((shuffleBlockId.shuffleId, shuffleBlockId.reduceId), size)}.toMap
+ val address = req.address
+ val mergedBlocksMetaListener = new MergedBlocksMetaListener {
+ override def onSuccess(shuffleId: Int, reduceId: Int, meta:
MergedBlockMeta): Unit = {
+ logInfo(s"Received the meta of merged block for ($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 _: Throwable =>
+ 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 blocks 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
+ if (isNotExecutorOrMergedLocal(address)) {
Review comment:
Added comments. PTAL.
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