Ngone51 commented on a change in pull request #30480: URL: https://github.com/apache/spark/pull/30480#discussion_r534973695
########## File path: core/src/main/scala/org/apache/spark/scheduler/MergeStatus.scala ########## @@ -0,0 +1,104 @@ +/* + * 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.scheduler + +import java.io.{Externalizable, ObjectInput, ObjectOutput} + +import org.roaringbitmap.RoaringBitmap + +import org.apache.spark.network.shuffle.protocol.MergeStatuses +import org.apache.spark.storage.BlockManagerId +import org.apache.spark.util.Utils + +/** + * The status for the result of merging shuffle partition blocks per individual shuffle partition + * maintained by the scheduler. The scheduler would separate the + * [[org.apache.spark.network.shuffle.protocol.MergeStatuses]] received from + * ExternalShuffleService into individual [[MergeStatus]] which is maintained inside + * MapOutputTracker to be served to the reducers when they start fetching shuffle partition + * blocks. Note that, the reducers are ultimately fetching individual chunks inside a merged + * shuffle file, as explained in [[org.apache.spark.network.shuffle.RemoteBlockPushResolver]]. + * Between the scheduler maintained MergeStatus and the shuffle service maintained per shuffle + * partition meta file, we are effectively dividing the metadata for a push-based shuffle into + * 2 layers. The scheduler would track the top-level metadata at the shuffle partition level + * with MergeStatus, and the shuffle service would maintain the partition level metadata about + * how to further divide a merged shuffle partition into multiple chunks with the per-partition + * meta file. This helps to reduce the amount of data the scheduler needs to maintain for + * push-based shuffle. + */ +private[spark] class MergeStatus( + private[this] var loc: BlockManagerId, + private[this] var mapTracker: RoaringBitmap, + private[this] var size: Long) + extends Externalizable with OutputStatus { + + protected def this() = this(null, null, -1) // For deserialization only + + def location: BlockManagerId = loc + + def totalSize: Long = size + + def tracker: RoaringBitmap = mapTracker + + /** + * Get the list of mapper IDs for missing mapper partition blocks that are not merged. + * The reducer will use this information to decide which shuffle partition blocks to + * fetch in the original way. + */ + def getMissingMaps(numMaps: Int): Seq[Int] = { Review comment: I see. I missed the necessary filed `numMaps`. Leave it as a function should be fine. ---------------------------------------------------------------- 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]
