kafka RemoteLogSegmentMetadataSnapshot 源码

  • 2022-10-20
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kafka RemoteLogSegmentMetadataSnapshot 代码


 * 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,
 * See the License for the specific language governing permissions and
 * limitations under the License.
package org.apache.kafka.server.log.remote.metadata.storage;

import org.apache.kafka.common.TopicIdPartition;
import org.apache.kafka.common.Uuid;
import org.apache.kafka.server.log.remote.storage.RemoteLogMetadata;
import org.apache.kafka.server.log.remote.storage.RemoteLogSegmentMetadata;
import org.apache.kafka.server.log.remote.storage.RemoteLogSegmentState;

import java.util.Collections;
import java.util.Map;
import java.util.NavigableMap;
import java.util.Objects;
import java.util.TreeMap;

 * This class represents the entry containing the metadata about a remote log segment. This is similar to
 * {@link RemoteLogSegmentMetadata} but it does not contain topic partition information. This class keeps
 * only remote log segment ID but not the topic partition.
 * This class is used in storing the snapshot of remote log metadata for a specific topic partition as mentioned
 * in {@link RemoteLogMetadataSnapshotFile.Snapshot}.
public class RemoteLogSegmentMetadataSnapshot extends RemoteLogMetadata {

     * Universally unique remote log segment id.
    private final Uuid segmentId;

     * Start offset of this segment.
    private final long startOffset;

     * End offset of this segment.
    private final long endOffset;

     * Maximum timestamp in milli seconds in the segment
    private final long maxTimestampMs;

     * LeaderEpoch vs offset for messages within this segment.
    private final NavigableMap<Integer, Long> segmentLeaderEpochs;

     * Size of the segment in bytes.
    private final int segmentSizeInBytes;

     * It indicates the state in which the action is executed on this segment.
    private final RemoteLogSegmentState state;

     * Creates an instance with the given metadata of remote log segment.
     * <p>
     * {@code segmentLeaderEpochs} can not be empty. If all the records in this segment belong to the same leader epoch
     * then it should have an entry with epoch mapping to start-offset of this segment.
     * @param segmentId                  Universally unique remote log segment id.
     * @param startOffset         Start offset of this segment (inclusive).
     * @param endOffset           End offset of this segment (inclusive).
     * @param maxTimestampMs      Maximum timestamp in milli seconds in this segment.
     * @param brokerId            Broker id from which this event is generated.
     * @param eventTimestampMs    Epoch time in milli seconds at which the remote log segment is copied to the remote tier storage.
     * @param segmentSizeInBytes  Size of this segment in bytes.
     * @param state               State of the respective segment of remoteLogSegmentId.
     * @param segmentLeaderEpochs leader epochs occurred within this segment.
    public RemoteLogSegmentMetadataSnapshot(Uuid segmentId,
                                            long startOffset,
                                            long endOffset,
                                            long maxTimestampMs,
                                            int brokerId,
                                            long eventTimestampMs,
                                            int segmentSizeInBytes,
                                            RemoteLogSegmentState state,
                                            Map<Integer, Long> segmentLeaderEpochs) {
        super(brokerId, eventTimestampMs);
        this.segmentId = Objects.requireNonNull(segmentId, "remoteLogSegmentId can not be null");
        this.state = Objects.requireNonNull(state, "state can not be null");

        this.startOffset = startOffset;
        this.endOffset = endOffset;
        this.maxTimestampMs = maxTimestampMs;
        this.segmentSizeInBytes = segmentSizeInBytes;

        if (segmentLeaderEpochs == null || segmentLeaderEpochs.isEmpty()) {
            throw new IllegalArgumentException("segmentLeaderEpochs can not be null or empty");

        this.segmentLeaderEpochs = Collections.unmodifiableNavigableMap(new TreeMap<>(segmentLeaderEpochs));

    public static RemoteLogSegmentMetadataSnapshot create(RemoteLogSegmentMetadata metadata) {
        return new RemoteLogSegmentMetadataSnapshot(metadata.remoteLogSegmentId().id(), metadata.startOffset(), metadata.endOffset(),
                                                    metadata.maxTimestampMs(), metadata.brokerId(), metadata.eventTimestampMs(),
                                                    metadata.segmentSizeInBytes(), metadata.state(), metadata.segmentLeaderEpochs());

     * @return unique id of this segment.
    public Uuid segmentId() {
        return segmentId;

     * @return Start offset of this segment (inclusive).
    public long startOffset() {
        return startOffset;

     * @return End offset of this segment (inclusive).
    public long endOffset() {
        return endOffset;

     * @return Total size of this segment in bytes.
    public int segmentSizeInBytes() {
        return segmentSizeInBytes;

     * @return Maximum timestamp in milli seconds of a record within this segment.
    public long maxTimestampMs() {
        return maxTimestampMs;

     * @return Map of leader epoch vs offset for the records available in this segment.
    public NavigableMap<Integer, Long> segmentLeaderEpochs() {
        return segmentLeaderEpochs;

     * Returns the current state of this remote log segment. It can be any of the below
     * <ul>
     *     {@link RemoteLogSegmentState#COPY_SEGMENT_STARTED}
     *     {@link RemoteLogSegmentState#COPY_SEGMENT_FINISHED}
     *     {@link RemoteLogSegmentState#DELETE_SEGMENT_STARTED}
     *     {@link RemoteLogSegmentState#DELETE_SEGMENT_FINISHED}
     * </ul>
    public RemoteLogSegmentState state() {
        return state;

    public TopicIdPartition topicIdPartition() {
        throw new UnsupportedOperationException("This metadata does not have topic partition with it.");

    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof RemoteLogSegmentMetadataSnapshot)) return false;
        RemoteLogSegmentMetadataSnapshot that = (RemoteLogSegmentMetadataSnapshot) o;
        return startOffset == that.startOffset && endOffset == that.endOffset && maxTimestampMs == that.maxTimestampMs && segmentSizeInBytes == that.segmentSizeInBytes && Objects.equals(
                segmentId, that.segmentId) && Objects.equals(segmentLeaderEpochs, that.segmentLeaderEpochs) && state == that.state;

    public int hashCode() {
        return Objects.hash(segmentId, startOffset, endOffset, maxTimestampMs, segmentLeaderEpochs, segmentSizeInBytes, state);

    public String toString() {
        return "RemoteLogSegmentMetadataSnapshot{" +
                "segmentId=" + segmentId +
                ", startOffset=" + startOffset +
                ", endOffset=" + endOffset +
                ", maxTimestampMs=" + maxTimestampMs +
                ", segmentLeaderEpochs=" + segmentLeaderEpochs +
                ", segmentSizeInBytes=" + segmentSizeInBytes +
                ", state=" + state +


kafka 源码目录


kafka CommittedOffsetsFile 源码

kafka ConsumerManager 源码

kafka ConsumerTask 源码

kafka FileBasedRemoteLogMetadataCache 源码

kafka ProducerManager 源码

kafka RemoteLogLeaderEpochState 源码

kafka RemoteLogMetadataCache 源码

kafka RemoteLogMetadataSnapshotFile 源码

kafka RemoteLogMetadataTopicPartitioner 源码

kafka RemotePartitionMetadataEventHandler 源码

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