ijuma commented on code in PR #14529: URL: https://github.com/apache/kafka/pull/14529#discussion_r1356966266
########## storage/src/main/java/org/apache/kafka/storage/internals/log/LogSegment.java: ########## @@ -0,0 +1,873 @@ +/* + * 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.kafka.storage.internals.log; + +import java.io.File; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.nio.file.Files; +import java.nio.file.NoSuchFileException; +import java.nio.file.attribute.FileTime; +import java.util.Iterator; +import java.util.Map; +import java.util.Optional; +import java.util.OptionalLong; +import java.util.concurrent.Callable; +import java.util.concurrent.TimeUnit; + +import com.yammer.metrics.core.MetricName; +import com.yammer.metrics.core.Timer; +import org.apache.kafka.common.InvalidRecordException; +import org.apache.kafka.common.errors.CorruptRecordException; +import org.apache.kafka.common.record.FileLogInputStream.FileChannelRecordBatch; +import org.apache.kafka.common.record.FileRecords; +import org.apache.kafka.common.record.FileRecords.LogOffsetPosition; +import org.apache.kafka.common.record.MemoryRecords; +import org.apache.kafka.common.record.RecordBatch; +import org.apache.kafka.common.utils.BufferSupplier; +import org.apache.kafka.common.utils.Time; +import org.apache.kafka.common.utils.Utils; +import org.apache.kafka.server.metrics.KafkaMetricsGroup; +import org.apache.kafka.storage.internals.epoch.LeaderEpochFileCache; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import org.slf4j.event.Level; + +import static java.util.Arrays.asList; + +/** + * A segment of the log. Each segment has two components: a log and an index. The log is a FileRecords containing + * the actual messages. The index is an OffsetIndex that maps from logical offsets to physical file positions. Each + * segment has a base offset which is an offset <= the least offset of any message in this segment and > any offset in + * any previous segment. + * + * A segment with a base offset of [base_offset] would be stored in two files, a [base_offset].index and a [base_offset].log file. + * + * This class is not thread-safe. + */ +public class LogSegment { + private static final Logger LOGGER = LoggerFactory.getLogger(LogSegment.class); + private static final Timer LOG_FLUSH_TIMER; + + static { + KafkaMetricsGroup logFlushStatsMetricsGroup = new KafkaMetricsGroup(LogSegment.class) { + @Override + public MetricName metricName(String name, Map<String, String> tags) { + // Override the group and type names for compatibility Review Comment: `group` and `type` is referring to the parameters we are passing to `explicitMetricName`, so I think it's explicit. I tweaked the comment a bit more to hopefully make it clearer. -- 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. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
