wsry commented on a change in pull request #13595: URL: https://github.com/apache/flink/pull/13595#discussion_r511591531
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/io/network/partition/PartitionSortedBuffer.java ########## @@ -0,0 +1,390 @@ +/* + * 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.flink.runtime.io.network.partition; + +import org.apache.flink.core.memory.MemorySegment; +import org.apache.flink.core.memory.MemorySegmentFactory; +import org.apache.flink.runtime.io.network.buffer.Buffer; +import org.apache.flink.runtime.io.network.buffer.BufferBuilder; +import org.apache.flink.runtime.io.network.buffer.BufferPool; +import org.apache.flink.runtime.io.network.buffer.NetworkBuffer; + +import javax.annotation.concurrent.NotThreadSafe; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.ArrayList; +import java.util.Arrays; + +import static org.apache.flink.runtime.io.network.buffer.Buffer.DataType; +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; +import static org.apache.flink.util.Preconditions.checkState; + +/** + * A {@link SortBuffer} implementation which sorts all appended records only by subpartition index. Records of the + * same subpartition keep the appended order. + * + * <p>It maintains a list of {@link MemorySegment}s as a joint buffer. Data will be appended to the joint buffer + * sequentially. When writing a record, an index entry will be appended first. Each index entry has 4 fields: 4 + * bytes record length, 4 bytes {@link DataType} and 8 bytes address pointing to the next index entry of the same + * channel which will be used to index the next record to read when coping data from this {@link SortBuffer}. For + * simplicity, no index entry can span multiple segments. The corresponding record data sits right after its index + * entry and different from the index entry, records have variable length thus may span multiple segments. + */ +@NotThreadSafe +public class PartitionSortedBuffer implements SortBuffer { + + /** + * Size of an index entry: 4 bytes for record length, 4 bytes for data type and 8 bytes + * for pointer to next entry. + */ + private static final int INDEX_ENTRY_SIZE = 4 + 4 + 8; Review comment: Good point, I can further optimize it in the future PRs. ---------------------------------------------------------------- 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]
