Victsm commented on a change in pull request #29855: URL: https://github.com/apache/spark/pull/29855#discussion_r503129900
########## File path: common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/MergedBlockMeta.java ########## @@ -0,0 +1,64 @@ +/* + * 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.network.shuffle; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.List; + +import com.google.common.base.Preconditions; +import io.netty.buffer.ByteBuf; +import io.netty.buffer.Unpooled; +import org.roaringbitmap.RoaringBitmap; + +import org.apache.spark.network.buffer.ManagedBuffer; +import org.apache.spark.network.protocol.Encoders; + +/** + * Contains meta information for a merged block. Currently this information constitutes: + * 1. Number of chunks in a merged shuffle block. + * 2. Bitmaps for each chunk in the merged block. A chunk bitmap contains all the mapIds that were + * merged to that merged block chunk. + */ +public class MergedBlockMeta { + private final int numChunks; + private final ManagedBuffer chunksBitmapBuffer; + + public MergedBlockMeta(int numChunks, ManagedBuffer chunksBitmapBuffer) { + this.numChunks = numChunks; + this.chunksBitmapBuffer = Preconditions.checkNotNull(chunksBitmapBuffer); + } + + public int getNumChunks() { + return numChunks; + } + + public ManagedBuffer getChunksBitmapBuffer() { + return chunksBitmapBuffer; + } + + public RoaringBitmap[] readChunkBitmaps() throws IOException { Review comment: The read action happens only once per MergedBlockMeta. This is used on the read path for push-based shuffle, when ShuffleBlockFetcherIterator attempts to read a merged shuffle partition. It would first send a request to the shuffle service to request this MergedBlockMeta, so it can break down a merged shuffle file into multiple smaller MB-sized chunks and fetch them separately, and handle fetch failure of individual chunks by falling back to fetching original blocks. Netty zero-copy transfer is leveraged there for transferring the bitmap buffer which is stored on shuffle service side as a file. More details around this would be more clear as we send out the following RBs. ---------------------------------------------------------------- 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]
