kafka LocalLog 源码
kafka LocalLog 代码
文件路径：/core/src/main/scala/kafka/log/LocalLog.scala
/**
* 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 kafka.log
import java.io.{File, IOException}
import java.nio.file.Files
import java.text.NumberFormat
import java.util.concurrent.atomic.AtomicLong
import java.util.regex.Pattern
import kafka.metrics.KafkaMetricsGroup
import kafka.server.{FetchDataInfo, LogDirFailureChannel, LogOffsetMetadata}
import kafka.utils.{Logging, Scheduler}
import org.apache.kafka.common.{KafkaException, TopicPartition}
import org.apache.kafka.common.errors.{KafkaStorageException, OffsetOutOfRangeException}
import org.apache.kafka.common.message.FetchResponseData
import org.apache.kafka.common.record.MemoryRecords
import org.apache.kafka.common.utils.{Time, Utils}
import scala.jdk.CollectionConverters._
import scala.collection.{Seq, immutable}
import scala.collection.mutable.{ArrayBuffer, ListBuffer}
/**
* Holds the result of splitting a segment into one or more segments, see LocalLog.splitOverflowedSegment().
*
* @param deletedSegments segments deleted when splitting a segment
* @param newSegments new segments created when splitting a segment
*/
case class SplitSegmentResult(deletedSegments: Iterable[LogSegment], newSegments: Iterable[LogSegment])
/**
* An append-only log for storing messages locally. The log is a sequence of LogSegments, each with a base offset.
* New log segments are created according to a configurable policy that controls the size in bytes or time interval
* for a given segment.
*
* NOTE: this class is not thread-safe, and it relies on the thread safety provided by the Log class.
*
* @param _dir The directory in which log segments are created.
* @param config The log configuration settings
* @param segments The non-empty log segments recovered from disk
* @param recoveryPoint The offset at which to begin the next recovery i.e. the first offset which has not been flushed to disk
* @param nextOffsetMetadata The offset where the next message could be appended
* @param scheduler The thread pool scheduler used for background actions
* @param time The time instance used for checking the clock
* @param topicPartition The topic partition associated with this log
* @param logDirFailureChannel The LogDirFailureChannel instance to asynchronously handle Log dir failure
*/
class LocalLog(@volatile private var _dir: File,
@volatile private[log] var config: LogConfig,
private[log] val segments: LogSegments,
@volatile private[log] var recoveryPoint: Long,
@volatile private var nextOffsetMetadata: LogOffsetMetadata,
private[log] val scheduler: Scheduler,
private[log] val time: Time,
private[log] val topicPartition: TopicPartition,
private[log] val logDirFailureChannel: LogDirFailureChannel) extends Logging with KafkaMetricsGroup {
import kafka.log.LocalLog._
this.logIdent = s"[LocalLog partition=$topicPartition, dir=${dir.getParent}] "
// The memory mapped buffer for index files of this log will be closed with either delete() or closeHandlers()
// After memory mapped buffer is closed, no disk IO operation should be performed for this log.
@volatile private[log] var isMemoryMappedBufferClosed = false
// Cache value of parent directory to avoid allocations in hot paths like ReplicaManager.checkpointHighWatermarks
@volatile private var _parentDir: String = dir.getParent
// Last time the log was flushed
private val lastFlushedTime = new AtomicLong(time.milliseconds)
private[log] def dir: File = _dir
private[log] def name: String = dir.getName
private[log] def parentDir: String = _parentDir
private[log] def parentDirFile: File = new File(_parentDir)
private[log] def isFuture: Boolean = dir.getName.endsWith(LocalLog.FutureDirSuffix)
private def maybeHandleIOException[T](msg: => String)(fun: => T): T = {
LocalLog.maybeHandleIOException(logDirFailureChannel, parentDir, msg) {
fun
}
}
/**
* Rename the directory of the log
* @param name the new dir name
* @throws KafkaStorageException if rename fails
*/
private[log] def renameDir(name: String): Boolean = {
maybeHandleIOException(s"Error while renaming dir for $topicPartition in log dir ${dir.getParent}") {
val renamedDir = new File(dir.getParent, name)
Utils.atomicMoveWithFallback(dir.toPath, renamedDir.toPath)
if (renamedDir != dir) {
_dir = renamedDir
_parentDir = renamedDir.getParent
segments.updateParentDir(renamedDir)
true
} else {
false
}
}
}
/**
* Update the existing configuration to the new provided configuration.
* @param newConfig the new configuration to be updated to
*/
private[log] def updateConfig(newConfig: LogConfig): Unit = {
val oldConfig = config
config = newConfig
val oldRecordVersion = oldConfig.recordVersion
val newRecordVersion = newConfig.recordVersion
if (newRecordVersion.precedes(oldRecordVersion))
warn(s"Record format version has been downgraded from $oldRecordVersion to $newRecordVersion.")
}
private[log] def checkIfMemoryMappedBufferClosed(): Unit = {
if (isMemoryMappedBufferClosed)
throw new KafkaStorageException(s"The memory mapped buffer for log of $topicPartition is already closed")
}
private[log] def updateRecoveryPoint(newRecoveryPoint: Long): Unit = {
recoveryPoint = newRecoveryPoint
}
/**
* Update recoveryPoint to provided offset and mark the log as flushed, if the offset is greater
* than the existing recoveryPoint.
*
* @param offset the offset to be updated
*/
private[log] def markFlushed(offset: Long): Unit = {
checkIfMemoryMappedBufferClosed()
if (offset > recoveryPoint) {
updateRecoveryPoint(offset)
lastFlushedTime.set(time.milliseconds)
}
}
/**
* The number of messages appended to the log since the last flush
*/
private[log] def unflushedMessages: Long = logEndOffset - recoveryPoint
/**
* Flush local log segments for all offsets up to offset-1.
* Does not update the recovery point.
*
* @param offset The offset to flush up to (non-inclusive)
*/
private[log] def flush(offset: Long): Unit = {
val currentRecoveryPoint = recoveryPoint
if (currentRecoveryPoint <= offset) {
val segmentsToFlush = segments.values(currentRecoveryPoint, offset)
segmentsToFlush.foreach(_.flush())
// If there are any new segments, we need to flush the parent directory for crash consistency.
if (segmentsToFlush.exists(_.baseOffset >= currentRecoveryPoint))
Utils.flushDir(dir.toPath)
}
}
/**
* The time this log is last known to have been fully flushed to disk
*/
private[log] def lastFlushTime: Long = lastFlushedTime.get
/**
* The offset metadata of the next message that will be appended to the log
*/
private[log] def logEndOffsetMetadata: LogOffsetMetadata = nextOffsetMetadata
/**
* The offset of the next message that will be appended to the log
*/
private[log] def logEndOffset: Long = nextOffsetMetadata.messageOffset
/**
* Update end offset of the log, and update the recoveryPoint.
*
* @param endOffset the new end offset of the log
*/
private[log] def updateLogEndOffset(endOffset: Long): Unit = {
nextOffsetMetadata = LogOffsetMetadata(endOffset, segments.activeSegment.baseOffset, segments.activeSegment.size)
if (recoveryPoint > endOffset) {
updateRecoveryPoint(endOffset)
}
}
/**
* Close file handlers used by log but don't write to disk.
* This is called if the log directory is offline.
*/
private[log] def closeHandlers(): Unit = {
segments.closeHandlers()
isMemoryMappedBufferClosed = true
}
/**
* Closes the segments of the log.
*/
private[log] def close(): Unit = {
maybeHandleIOException(s"Error while renaming dir for $topicPartition in dir ${dir.getParent}") {
checkIfMemoryMappedBufferClosed()
segments.close()
}
}
/**
* Completely delete this log directory with no delay.
*/
private[log] def deleteEmptyDir(): Unit = {
maybeHandleIOException(s"Error while deleting dir for $topicPartition in dir ${dir.getParent}") {
if (segments.nonEmpty) {
throw new IllegalStateException(s"Can not delete directory when ${segments.numberOfSegments} segments are still present")
}
if (!isMemoryMappedBufferClosed) {
throw new IllegalStateException(s"Can not delete directory when memory mapped buffer for log of $topicPartition is still open.")
}
Utils.delete(dir)
}
}
/**
* Completely delete all segments with no delay.
* @return the deleted segments
*/
private[log] def deleteAllSegments(): Iterable[LogSegment] = {
maybeHandleIOException(s"Error while deleting all segments for $topicPartition in dir ${dir.getParent}") {
val deletableSegments = List[LogSegment]() ++ segments.values
removeAndDeleteSegments(segments.values, asyncDelete = false, LogDeletion(this))
isMemoryMappedBufferClosed = true
deletableSegments
}
}
/**
* Find segments starting from the oldest until the user-supplied predicate is false.
* A final segment that is empty will never be returned.
*
* @param predicate A function that takes in a candidate log segment, the next higher segment
* (if there is one). It returns true iff the segment is deletable.
* @return the segments ready to be deleted
*/
private[log] def deletableSegments(predicate: (LogSegment, Option[LogSegment]) => Boolean): Iterable[LogSegment] = {
if (segments.isEmpty) {
Seq.empty
} else {
val deletable = ArrayBuffer.empty[LogSegment]
val segmentsIterator = segments.values.iterator
var segmentOpt = nextOption(segmentsIterator)
while (segmentOpt.isDefined) {
val segment = segmentOpt.get
val nextSegmentOpt = nextOption(segmentsIterator)
val isLastSegmentAndEmpty = nextSegmentOpt.isEmpty && segment.size == 0
if (predicate(segment, nextSegmentOpt) && !isLastSegmentAndEmpty) {
deletable += segment
segmentOpt = nextSegmentOpt
} else {
segmentOpt = Option.empty
}
}
deletable
}
}
/**
* This method deletes the given log segments by doing the following for each of them:
* - It removes the segment from the segment map so that it will no longer be used for reads.
* - It renames the index and log files by appending .deleted to the respective file name
* - It can either schedule an asynchronous delete operation to occur in the future or perform the deletion synchronously
*
* Asynchronous deletion allows reads to happen concurrently without synchronization and without the possibility of
* physically deleting a file while it is being read.
*
* This method does not convert IOException to KafkaStorageException, the immediate caller
* is expected to catch and handle IOException.
*
* @param segmentsToDelete The log segments to schedule for deletion
* @param asyncDelete Whether the segment files should be deleted asynchronously
* @param reason The reason for the segment deletion
*/
private[log] def removeAndDeleteSegments(segmentsToDelete: Iterable[LogSegment],
asyncDelete: Boolean,
reason: SegmentDeletionReason): Unit = {
if (segmentsToDelete.nonEmpty) {
// Most callers hold an iterator into the `segments` collection and `removeAndDeleteSegment` mutates it by
// removing the deleted segment, we should force materialization of the iterator here, so that results of the
// iteration remain valid and deterministic. We should also pass only the materialized view of the
// iterator to the logic that actually deletes the segments.
val toDelete = segmentsToDelete.toList
reason.logReason(toDelete)
toDelete.foreach { segment =>
segments.remove(segment.baseOffset)
}
LocalLog.deleteSegmentFiles(toDelete, asyncDelete, dir, topicPartition, config, scheduler, logDirFailureChannel, logIdent)
}
}
/**
* This method deletes the given segment and creates a new segment with the given new base offset. It ensures an
* active segment exists in the log at all times during this process.
*
* Asynchronous deletion allows reads to happen concurrently without synchronization and without the possibility of
* physically deleting a file while it is being read.
*
* This method does not convert IOException to KafkaStorageException, the immediate caller
* is expected to catch and handle IOException.
*
* @param newOffset The base offset of the new segment
* @param segmentToDelete The old active segment to schedule for deletion
* @param asyncDelete Whether the segment files should be deleted asynchronously
* @param reason The reason for the segment deletion
*/
private[log] def createAndDeleteSegment(newOffset: Long,
segmentToDelete: LogSegment,
asyncDelete: Boolean,
reason: SegmentDeletionReason): LogSegment = {
if (newOffset == segmentToDelete.baseOffset)
segmentToDelete.changeFileSuffixes("", DeletedFileSuffix)
val newSegment = LogSegment.open(dir,
baseOffset = newOffset,
config,
time = time,
initFileSize = config.initFileSize,
preallocate = config.preallocate)
segments.add(newSegment)
reason.logReason(List(segmentToDelete))
if (newOffset != segmentToDelete.baseOffset)
segments.remove(segmentToDelete.baseOffset)
LocalLog.deleteSegmentFiles(List(segmentToDelete), asyncDelete, dir, topicPartition, config, scheduler, logDirFailureChannel, logIdent)
newSegment
}
/**
* Given a message offset, find its corresponding offset metadata in the log.
* If the message offset is out of range, throw an OffsetOutOfRangeException
*/
private[log] def convertToOffsetMetadataOrThrow(offset: Long): LogOffsetMetadata = {
val fetchDataInfo = read(offset,
maxLength = 1,
minOneMessage = false,
maxOffsetMetadata = nextOffsetMetadata,
includeAbortedTxns = false)
fetchDataInfo.fetchOffsetMetadata
}
/**
* Read messages from the log.
*
* @param startOffset The offset to begin reading at
* @param maxLength The maximum number of bytes to read
* @param minOneMessage If this is true, the first message will be returned even if it exceeds `maxLength` (if one exists)
* @param maxOffsetMetadata The metadata of the maximum offset to be fetched
* @param includeAbortedTxns If true, aborted transactions are included
* @throws OffsetOutOfRangeException If startOffset is beyond the log end offset
* @return The fetch data information including fetch starting offset metadata and messages read.
*/
def read(startOffset: Long,
maxLength: Int,
minOneMessage: Boolean,
maxOffsetMetadata: LogOffsetMetadata,
includeAbortedTxns: Boolean): FetchDataInfo = {
maybeHandleIOException(s"Exception while reading from $topicPartition in dir ${dir.getParent}") {
trace(s"Reading maximum $maxLength bytes at offset $startOffset from log with " +
s"total length ${segments.sizeInBytes} bytes")
val endOffsetMetadata = nextOffsetMetadata
val endOffset = endOffsetMetadata.messageOffset
var segmentOpt = segments.floorSegment(startOffset)
// return error on attempt to read beyond the log end offset
if (startOffset > endOffset || segmentOpt.isEmpty)
throw new OffsetOutOfRangeException(s"Received request for offset $startOffset for partition $topicPartition, " +
s"but we only have log segments upto $endOffset.")
if (startOffset == maxOffsetMetadata.messageOffset)
emptyFetchDataInfo(maxOffsetMetadata, includeAbortedTxns)
else if (startOffset > maxOffsetMetadata.messageOffset)
emptyFetchDataInfo(convertToOffsetMetadataOrThrow(startOffset), includeAbortedTxns)
else {
// Do the read on the segment with a base offset less than the target offset
// but if that segment doesn't contain any messages with an offset greater than that
// continue to read from successive segments until we get some messages or we reach the end of the log
var fetchDataInfo: FetchDataInfo = null
while (fetchDataInfo == null && segmentOpt.isDefined) {
val segment = segmentOpt.get
val baseOffset = segment.baseOffset
val maxPosition =
// Use the max offset position if it is on this segment; otherwise, the segment size is the limit.
if (maxOffsetMetadata.segmentBaseOffset == segment.baseOffset) maxOffsetMetadata.relativePositionInSegment
else segment.size
fetchDataInfo = segment.read(startOffset, maxLength, maxPosition, minOneMessage)
if (fetchDataInfo != null) {
if (includeAbortedTxns)
fetchDataInfo = addAbortedTransactions(startOffset, segment, fetchDataInfo)
} else segmentOpt = segments.higherSegment(baseOffset)
}
if (fetchDataInfo != null) fetchDataInfo
else {
// okay we are beyond the end of the last segment with no data fetched although the start offset is in range,
// this can happen when all messages with offset larger than start offsets have been deleted.
// In this case, we will return the empty set with log end offset metadata
FetchDataInfo(nextOffsetMetadata, MemoryRecords.EMPTY)
}
}
}
}
private[log] def append(lastOffset: Long, largestTimestamp: Long, shallowOffsetOfMaxTimestamp: Long, records: MemoryRecords): Unit = {
segments.activeSegment.append(largestOffset = lastOffset, largestTimestamp = largestTimestamp,
shallowOffsetOfMaxTimestamp = shallowOffsetOfMaxTimestamp, records = records)
updateLogEndOffset(lastOffset + 1)
}
private def addAbortedTransactions(startOffset: Long, segment: LogSegment,
fetchInfo: FetchDataInfo): FetchDataInfo = {
val fetchSize = fetchInfo.records.sizeInBytes
val startOffsetPosition = OffsetPosition(fetchInfo.fetchOffsetMetadata.messageOffset,
fetchInfo.fetchOffsetMetadata.relativePositionInSegment)
val upperBoundOffset = segment.fetchUpperBoundOffset(startOffsetPosition, fetchSize).getOrElse {
segments.higherSegment(segment.baseOffset).map(_.baseOffset).getOrElse(logEndOffset)
}
val abortedTransactions = ListBuffer.empty[FetchResponseData.AbortedTransaction]
def accumulator(abortedTxns: List[AbortedTxn]): Unit = abortedTransactions ++= abortedTxns.map(_.asAbortedTransaction)
collectAbortedTransactions(startOffset, upperBoundOffset, segment, accumulator)
FetchDataInfo(fetchOffsetMetadata = fetchInfo.fetchOffsetMetadata,
records = fetchInfo.records,
firstEntryIncomplete = fetchInfo.firstEntryIncomplete,
abortedTransactions = Some(abortedTransactions.toList))
}
private def collectAbortedTransactions(startOffset: Long, upperBoundOffset: Long,
startingSegment: LogSegment,
accumulator: List[AbortedTxn] => Unit): Unit = {
val higherSegments = segments.higherSegments(startingSegment.baseOffset).iterator
var segmentEntryOpt = Option(startingSegment)
while (segmentEntryOpt.isDefined) {
val segment = segmentEntryOpt.get
val searchResult = segment.collectAbortedTxns(startOffset, upperBoundOffset)
accumulator(searchResult.abortedTransactions)
if (searchResult.isComplete)
return
segmentEntryOpt = nextOption(higherSegments)
}
}
private[log] def collectAbortedTransactions(logStartOffset: Long, baseOffset: Long, upperBoundOffset: Long): List[AbortedTxn] = {
val segmentEntry = segments.floorSegment(baseOffset)
val allAbortedTxns = ListBuffer.empty[AbortedTxn]
def accumulator(abortedTxns: List[AbortedTxn]): Unit = allAbortedTxns ++= abortedTxns
segmentEntry.foreach(segment => collectAbortedTransactions(logStartOffset, upperBoundOffset, segment, accumulator))
allAbortedTxns.toList
}
/**
* Roll the log over to a new active segment starting with the current logEndOffset.
* This will trim the index to the exact size of the number of entries it currently contains.
*
* @param expectedNextOffset The expected next offset after the segment is rolled
*
* @return The newly rolled segment
*/
private[log] def roll(expectedNextOffset: Option[Long] = None): LogSegment = {
maybeHandleIOException(s"Error while rolling log segment for $topicPartition in dir ${dir.getParent}") {
val start = time.hiResClockMs()
checkIfMemoryMappedBufferClosed()
val newOffset = math.max(expectedNextOffset.getOrElse(0L), logEndOffset)
val logFile = LocalLog.logFile(dir, newOffset)
val activeSegment = segments.activeSegment
if (segments.contains(newOffset)) {
// segment with the same base offset already exists and loaded
if (activeSegment.baseOffset == newOffset && activeSegment.size == 0) {
// We have seen this happen (see KAFKA-6388) after shouldRoll() returns true for an
// active segment of size zero because of one of the indexes is "full" (due to _maxEntries == 0).
warn(s"Trying to roll a new log segment with start offset $newOffset " +
s"=max(provided offset = $expectedNextOffset, LEO = $logEndOffset) while it already " +
s"exists and is active with size 0. Size of time index: ${activeSegment.timeIndex.entries}," +
s" size of offset index: ${activeSegment.offsetIndex.entries}.")
val newSegment = createAndDeleteSegment(newOffset, activeSegment, asyncDelete = true, LogRoll(this))
updateLogEndOffset(nextOffsetMetadata.messageOffset)
info(s"Rolled new log segment at offset $newOffset in ${time.hiResClockMs() - start} ms.")
return newSegment
} else {
throw new KafkaException(s"Trying to roll a new log segment for topic partition $topicPartition with start offset $newOffset" +
s" =max(provided offset = $expectedNextOffset, LEO = $logEndOffset) while it already exists. Existing " +
s"segment is ${segments.get(newOffset)}.")
}
} else if (!segments.isEmpty && newOffset < activeSegment.baseOffset) {
throw new KafkaException(
s"Trying to roll a new log segment for topic partition $topicPartition with " +
s"start offset $newOffset =max(provided offset = $expectedNextOffset, LEO = $logEndOffset) lower than start offset of the active segment $activeSegment")
} else {
val offsetIdxFile = offsetIndexFile(dir, newOffset)
val timeIdxFile = timeIndexFile(dir, newOffset)
val txnIdxFile = transactionIndexFile(dir, newOffset)
for (file <- List(logFile, offsetIdxFile, timeIdxFile, txnIdxFile) if file.exists) {
warn(s"Newly rolled segment file ${file.getAbsolutePath} already exists; deleting it first")
Files.delete(file.toPath)
}
segments.lastSegment.foreach(_.onBecomeInactiveSegment())
}
val newSegment = LogSegment.open(dir,
baseOffset = newOffset,
config,
time = time,
initFileSize = config.initFileSize,
preallocate = config.preallocate)
segments.add(newSegment)
// We need to update the segment base offset and append position data of the metadata when log rolls.
// The next offset should not change.
updateLogEndOffset(nextOffsetMetadata.messageOffset)
info(s"Rolled new log segment at offset $newOffset in ${time.hiResClockMs() - start} ms.")
newSegment
}
}
/**
* Delete all data in the local log and start at the new offset.
*
* @param newOffset The new offset to start the log with
* @return the list of segments that were scheduled for deletion
*/
private[log] def truncateFullyAndStartAt(newOffset: Long): Iterable[LogSegment] = {
maybeHandleIOException(s"Error while truncating the entire log for $topicPartition in dir ${dir.getParent}") {
debug(s"Truncate and start at offset $newOffset")
checkIfMemoryMappedBufferClosed()
val segmentsToDelete = List[LogSegment]() ++ segments.values
if (segmentsToDelete.nonEmpty) {
removeAndDeleteSegments(segmentsToDelete.dropRight(1), asyncDelete = true, LogTruncation(this))
// Use createAndDeleteSegment() to create new segment first and then delete the old last segment to prevent missing
// active segment during the deletion process
createAndDeleteSegment(newOffset, segmentsToDelete.last, asyncDelete = true, LogTruncation(this))
}
updateLogEndOffset(newOffset)
segmentsToDelete
}
}
/**
* Truncate this log so that it ends with the greatest offset < targetOffset.
*
* @param targetOffset The offset to truncate to, an upper bound on all offsets in the log after truncation is complete.
* @return the list of segments that were scheduled for deletion
*/
private[log] def truncateTo(targetOffset: Long): Iterable[LogSegment] = {
val deletableSegments = List[LogSegment]() ++ segments.filter(segment => segment.baseOffset > targetOffset)
removeAndDeleteSegments(deletableSegments, asyncDelete = true, LogTruncation(this))
segments.activeSegment.truncateTo(targetOffset)
updateLogEndOffset(targetOffset)
deletableSegments
}
}
/**
* Helper functions for logs
*/
object LocalLog extends Logging {
/** a log file */
private[log] val LogFileSuffix = ".log"
/** an index file */
private[log] val IndexFileSuffix = ".index"
/** a time index file */
private[log] val TimeIndexFileSuffix = ".timeindex"
/** an (aborted) txn index */
private[log] val TxnIndexFileSuffix = ".txnindex"
/** a file that is scheduled to be deleted */
private[log] val DeletedFileSuffix = ".deleted"
/** A temporary file that is being used for log cleaning */
private[log] val CleanedFileSuffix = ".cleaned"
/** A temporary file used when swapping files into the log */
private[log] val SwapFileSuffix = ".swap"
/** a directory that is scheduled to be deleted */
private[log] val DeleteDirSuffix = "-delete"
/** a directory that is used for future partition */
private[log] val FutureDirSuffix = "-future"
private[log] val DeleteDirPattern = Pattern.compile(s"^(\\S+)-(\\S+)\\.(\\S+)$DeleteDirSuffix")
private[log] val FutureDirPattern = Pattern.compile(s"^(\\S+)-(\\S+)\\.(\\S+)$FutureDirSuffix")
private[log] val UnknownOffset = -1L
/**
* Make log segment file name from offset bytes. All this does is pad out the offset number with zeros
* so that ls sorts the files numerically.
*
* @param offset The offset to use in the file name
* @return The filename
*/
private[log] def filenamePrefixFromOffset(offset: Long): String = {
val nf = NumberFormat.getInstance()
nf.setMinimumIntegerDigits(20)
nf.setMaximumFractionDigits(0)
nf.setGroupingUsed(false)
nf.format(offset)
}
/**
* Construct a log file name in the given dir with the given base offset and the given suffix
*
* @param dir The directory in which the log will reside
* @param offset The base offset of the log file
* @param suffix The suffix to be appended to the file name (e.g. "", ".deleted", ".cleaned", ".swap", etc.)
*/
private[log] def logFile(dir: File, offset: Long, suffix: String = ""): File =
new File(dir, filenamePrefixFromOffset(offset) + LogFileSuffix + suffix)
/**
* Return a directory name to rename the log directory to for async deletion.
* The name will be in the following format: "topic-partitionId.uniqueId-delete".
* If the topic name is too long, it will be truncated to prevent the total name
* from exceeding 255 characters.
*/
private[log] def logDeleteDirName(topicPartition: TopicPartition): String = {
val uniqueId = java.util.UUID.randomUUID.toString.replaceAll("-", "")
val suffix = s"-${topicPartition.partition()}.$uniqueId$DeleteDirSuffix"
val prefixLength = Math.min(topicPartition.topic().size, 255 - suffix.size)
s"${topicPartition.topic().substring(0, prefixLength)}$suffix"
}
/**
* Return a future directory name for the given topic partition. The name will be in the following
* format: topic-partition.uniqueId-future where topic, partition and uniqueId are variables.
*/
private[log] def logFutureDirName(topicPartition: TopicPartition): String = {
logDirNameWithSuffix(topicPartition, FutureDirSuffix)
}
private[log] def logDirNameWithSuffix(topicPartition: TopicPartition, suffix: String): String = {
val uniqueId = java.util.UUID.randomUUID.toString.replaceAll("-", "")
s"${logDirName(topicPartition)}.$uniqueId$suffix"
}
/**
* Return a directory name for the given topic partition. The name will be in the following
* format: topic-partition where topic, partition are variables.
*/
private[log] def logDirName(topicPartition: TopicPartition): String = {
s"${topicPartition.topic}-${topicPartition.partition}"
}
/**
* Construct an index file name in the given dir using the given base offset and the given suffix
*
* @param dir The directory in which the log will reside
* @param offset The base offset of the log file
* @param suffix The suffix to be appended to the file name ("", ".deleted", ".cleaned", ".swap", etc.)
*/
private[log] def offsetIndexFile(dir: File, offset: Long, suffix: String = ""): File =
new File(dir, filenamePrefixFromOffset(offset) + IndexFileSuffix + suffix)
/**
* Construct a time index file name in the given dir using the given base offset and the given suffix
*
* @param dir The directory in which the log will reside
* @param offset The base offset of the log file
* @param suffix The suffix to be appended to the file name ("", ".deleted", ".cleaned", ".swap", etc.)
*/
private[log] def timeIndexFile(dir: File, offset: Long, suffix: String = ""): File =
new File(dir, filenamePrefixFromOffset(offset) + TimeIndexFileSuffix + suffix)
/**
* Construct a transaction index file name in the given dir using the given base offset and the given suffix
*
* @param dir The directory in which the log will reside
* @param offset The base offset of the log file
* @param suffix The suffix to be appended to the file name ("", ".deleted", ".cleaned", ".swap", etc.)
*/
private[log] def transactionIndexFile(dir: File, offset: Long, suffix: String = ""): File =
new File(dir, filenamePrefixFromOffset(offset) + TxnIndexFileSuffix + suffix)
private[log] def offsetFromFileName(filename: String): Long = {
filename.substring(0, filename.indexOf('.')).toLong
}
private[log] def offsetFromFile(file: File): Long = {
offsetFromFileName(file.getName)
}
/**
* Parse the topic and partition out of the directory name of a log
*/
private[log] def parseTopicPartitionName(dir: File): TopicPartition = {
if (dir == null)
throw new KafkaException("dir should not be null")
def exception(dir: File): KafkaException = {
new KafkaException(s"Found directory ${dir.getCanonicalPath}, '${dir.getName}' is not in the form of " +
"topic-partition or topic-partition.uniqueId-delete (if marked for deletion).\n" +
"Kafka's log directories (and children) should only contain Kafka topic data.")
}
val dirName = dir.getName
if (dirName == null || dirName.isEmpty || !dirName.contains('-'))
throw exception(dir)
if (dirName.endsWith(DeleteDirSuffix) && !DeleteDirPattern.matcher(dirName).matches ||
dirName.endsWith(FutureDirSuffix) && !FutureDirPattern.matcher(dirName).matches)
throw exception(dir)
val name: String =
if (dirName.endsWith(DeleteDirSuffix) || dirName.endsWith(FutureDirSuffix)) dirName.substring(0, dirName.lastIndexOf('.'))
else dirName
val index = name.lastIndexOf('-')
val topic = name.substring(0, index)
val partitionString = name.substring(index + 1)
if (topic.isEmpty || partitionString.isEmpty)
throw exception(dir)
val partition =
try partitionString.toInt
catch { case _: NumberFormatException => throw exception(dir) }
new TopicPartition(topic, partition)
}
private[log] def isIndexFile(file: File): Boolean = {
val filename = file.getName
filename.endsWith(IndexFileSuffix) || filename.endsWith(TimeIndexFileSuffix) || filename.endsWith(TxnIndexFileSuffix)
}
private[log] def isLogFile(file: File): Boolean =
file.getPath.endsWith(LogFileSuffix)
/**
* Invokes the provided function and handles any IOException raised by the function by marking the
* provided directory offline.
*
* @param logDirFailureChannel Used to asynchronously handle log directory failure.
* @param logDir The log directory to be marked offline during an IOException.
* @param errorMsg The error message to be used when marking the log directory offline.
* @param fun The function to be executed.
* @return The value returned by the function after a successful invocation
*/
private[log] def maybeHandleIOException[T](logDirFailureChannel: LogDirFailureChannel,
logDir: String,
errorMsg: => String)(fun: => T): T = {
if (logDirFailureChannel.hasOfflineLogDir(logDir)) {
throw new KafkaStorageException(s"The log dir $logDir is already offline due to a previous IO exception.")
}
try {
fun
} catch {
case e: IOException =>
logDirFailureChannel.maybeAddOfflineLogDir(logDir, errorMsg, e)
throw new KafkaStorageException(errorMsg, e)
}
}
/**
* Split a segment into one or more segments such that there is no offset overflow in any of them. The
* resulting segments will contain the exact same messages that are present in the input segment. On successful
* completion of this method, the input segment will be deleted and will be replaced by the resulting new segments.
* See replaceSegments for recovery logic, in case the broker dies in the middle of this operation.
*
* Note that this method assumes we have already determined that the segment passed in contains records that cause
* offset overflow.
*
* The split logic overloads the use of .clean files that LogCleaner typically uses to make the process of replacing
* the input segment with multiple new segments atomic and recoverable in the event of a crash. See replaceSegments
* and completeSwapOperations for the implementation to make this operation recoverable on crashes.</p>
*
* @param segment Segment to split
* @param existingSegments The existing segments of the log
* @param dir The directory in which the log will reside
* @param topicPartition The topic
* @param config The log configuration settings
* @param scheduler The thread pool scheduler used for background actions
* @param logDirFailureChannel The LogDirFailureChannel to asynchronously handle log dir failure
* @param logPrefix The logging prefix
* @return List of new segments that replace the input segment
*/
private[log] def splitOverflowedSegment(segment: LogSegment,
existingSegments: LogSegments,
dir: File,
topicPartition: TopicPartition,
config: LogConfig,
scheduler: Scheduler,
logDirFailureChannel: LogDirFailureChannel,
logPrefix: String): SplitSegmentResult = {
require(isLogFile(segment.log.file), s"Cannot split file ${segment.log.file.getAbsoluteFile}")
require(segment.hasOverflow, s"Split operation is only permitted for segments with overflow, and the problem path is ${segment.log.file.getAbsoluteFile}")
info(s"${logPrefix}Splitting overflowed segment $segment")
val newSegments = ListBuffer[LogSegment]()
try {
var position = 0
val sourceRecords = segment.log
while (position < sourceRecords.sizeInBytes) {
val firstBatch = sourceRecords.batchesFrom(position).asScala.head
val newSegment = createNewCleanedSegment(dir, config, firstBatch.baseOffset)
newSegments += newSegment
val bytesAppended = newSegment.appendFromFile(sourceRecords, position)
if (bytesAppended == 0)
throw new IllegalStateException(s"Failed to append records from position $position in $segment")
position += bytesAppended
}
// prepare new segments
var totalSizeOfNewSegments = 0
newSegments.foreach { splitSegment =>
splitSegment.onBecomeInactiveSegment()
splitSegment.flush()
splitSegment.lastModified = segment.lastModified
totalSizeOfNewSegments += splitSegment.log.sizeInBytes
}
// size of all the new segments combined must equal size of the original segment
if (totalSizeOfNewSegments != segment.log.sizeInBytes)
throw new IllegalStateException("Inconsistent segment sizes after split" +
s" before: ${segment.log.sizeInBytes} after: $totalSizeOfNewSegments")
// replace old segment with new ones
info(s"${logPrefix}Replacing overflowed segment $segment with split segments $newSegments")
val newSegmentsToAdd = newSegments.toSeq
val deletedSegments = LocalLog.replaceSegments(existingSegments, newSegmentsToAdd, List(segment),
dir, topicPartition, config, scheduler, logDirFailureChannel, logPrefix)
SplitSegmentResult(deletedSegments.toSeq, newSegmentsToAdd)
} catch {
case e: Exception =>
newSegments.foreach { splitSegment =>
splitSegment.close()
splitSegment.deleteIfExists()
}
throw e
}
}
/**
* Swap one or more new segment in place and delete one or more existing segments in a crash-safe
* manner. The old segments will be asynchronously deleted.
*
* This method does not need to convert IOException to KafkaStorageException because it is either
* called before all logs are loaded or the caller will catch and handle IOException
*
* The sequence of operations is:
*
* - Cleaner creates one or more new segments with suffix .cleaned and invokes replaceSegments() on
* the Log instance. If broker crashes at this point, the clean-and-swap operation is aborted and
* the .cleaned files are deleted on recovery in LogLoader.
* - New segments are renamed .swap. If the broker crashes before all segments were renamed to .swap, the
* clean-and-swap operation is aborted - .cleaned as well as .swap files are deleted on recovery in
* in LogLoader. We detect this situation by maintaining a specific order in which files are renamed
* from .cleaned to .swap. Basically, files are renamed in descending order of offsets. On recovery,
* all .swap files whose offset is greater than the minimum-offset .clean file are deleted.
* - If the broker crashes after all new segments were renamed to .swap, the operation is completed,
* the swap operation is resumed on recovery as described in the next step.
* - Old segment files are renamed to .deleted and asynchronous delete is scheduled. If the broker
* crashes, any .deleted files left behind are deleted on recovery in LogLoader.
* replaceSegments() is then invoked to complete the swap with newSegment recreated from the
* .swap file and oldSegments containing segments which were not renamed before the crash.
* - Swap segment(s) are renamed to replace the existing segments, completing this operation.
* If the broker crashes, any .deleted files which may be left behind are deleted
* on recovery in LogLoader.
*
* @param existingSegments The existing segments of the log
* @param newSegments The new log segment to add to the log
* @param oldSegments The old log segments to delete from the log
* @param dir The directory in which the log will reside
* @param topicPartition The topic
* @param config The log configuration settings
* @param scheduler The thread pool scheduler used for background actions
* @param logDirFailureChannel The LogDirFailureChannel to asynchronously handle log dir failure
* @param logPrefix The logging prefix
* @param isRecoveredSwapFile true if the new segment was created from a swap file during recovery after a crash
*/
private[log] def replaceSegments(existingSegments: LogSegments,
newSegments: Seq[LogSegment],
oldSegments: Seq[LogSegment],
dir: File,
topicPartition: TopicPartition,
config: LogConfig,
scheduler: Scheduler,
logDirFailureChannel: LogDirFailureChannel,
logPrefix: String,
isRecoveredSwapFile: Boolean = false): Iterable[LogSegment] = {
val sortedNewSegments = newSegments.sortBy(_.baseOffset)
// Some old segments may have been removed from index and scheduled for async deletion after the caller reads segments
// but before this method is executed. We want to filter out those segments to avoid calling deleteSegmentFiles()
// multiple times for the same segment.
val sortedOldSegments = oldSegments.filter(seg => existingSegments.contains(seg.baseOffset)).sortBy(_.baseOffset)
// need to do this in two phases to be crash safe AND do the delete asynchronously
// if we crash in the middle of this we complete the swap in loadSegments()
if (!isRecoveredSwapFile)
sortedNewSegments.reverse.foreach(_.changeFileSuffixes(CleanedFileSuffix, SwapFileSuffix))
sortedNewSegments.reverse.foreach(existingSegments.add)
val newSegmentBaseOffsets = sortedNewSegments.map(_.baseOffset).toSet
// delete the old files
val deletedNotReplaced = sortedOldSegments.map { seg =>
// remove the index entry
if (seg.baseOffset != sortedNewSegments.head.baseOffset)
existingSegments.remove(seg.baseOffset)
deleteSegmentFiles(
List(seg),
asyncDelete = true,
dir,
topicPartition,
config,
scheduler,
logDirFailureChannel,
logPrefix)
if (newSegmentBaseOffsets.contains(seg.baseOffset)) Option.empty else Some(seg)
}.filter(item => item.isDefined).map(item => item.get)
// okay we are safe now, remove the swap suffix
sortedNewSegments.foreach(_.changeFileSuffixes(SwapFileSuffix, ""))
Utils.flushDir(dir.toPath)
deletedNotReplaced
}
/**
* Perform physical deletion of the index and log files for the given segment.
* Prior to the deletion, the index and log files are renamed by appending .deleted to the
* respective file name. Allows these files to be optionally deleted asynchronously.
*
* This method assumes that the file exists. It does not need to convert IOException
* (thrown from changeFileSuffixes) to KafkaStorageException because it is either called before
* all logs are loaded or the caller will catch and handle IOException.
*
* @param segmentsToDelete The segments to be deleted
* @param asyncDelete If true, the deletion of the segments is done asynchronously
* @param dir The directory in which the log will reside
* @param topicPartition The topic
* @param config The log configuration settings
* @param scheduler The thread pool scheduler used for background actions
* @param logDirFailureChannel The LogDirFailureChannel to asynchronously handle log dir failure
* @param logPrefix The logging prefix
* @throws IOException if the file can't be renamed and still exists
*/
private[log] def deleteSegmentFiles(segmentsToDelete: immutable.Iterable[LogSegment],
asyncDelete: Boolean,
dir: File,
topicPartition: TopicPartition,
config: LogConfig,
scheduler: Scheduler,
logDirFailureChannel: LogDirFailureChannel,
logPrefix: String): Unit = {
segmentsToDelete.foreach { segment =>
if (!segment.hasSuffix(DeletedFileSuffix))
segment.changeFileSuffixes("", DeletedFileSuffix)
}
def deleteSegments(): Unit = {
info(s"${logPrefix}Deleting segment files ${segmentsToDelete.mkString(",")}")
val parentDir = dir.getParent
maybeHandleIOException(logDirFailureChannel, parentDir, s"Error while deleting segments for $topicPartition in dir $parentDir") {
segmentsToDelete.foreach { segment =>
segment.deleteIfExists()
}
}
}
if (asyncDelete)
scheduler.schedule("delete-file", () => deleteSegments(), delay = config.fileDeleteDelayMs)
else
deleteSegments()
}
private[log] def emptyFetchDataInfo(fetchOffsetMetadata: LogOffsetMetadata,
includeAbortedTxns: Boolean): FetchDataInfo = {
val abortedTransactions =
if (includeAbortedTxns) Some(List.empty[FetchResponseData.AbortedTransaction])
else None
FetchDataInfo(fetchOffsetMetadata,
MemoryRecords.EMPTY,
abortedTransactions = abortedTransactions)
}
private[log] def createNewCleanedSegment(dir: File, logConfig: LogConfig, baseOffset: Long): LogSegment = {
LogSegment.deleteIfExists(dir, baseOffset, fileSuffix = CleanedFileSuffix)
LogSegment.open(dir, baseOffset, logConfig, Time.SYSTEM,
fileSuffix = CleanedFileSuffix, initFileSize = logConfig.initFileSize, preallocate = logConfig.preallocate)
}
/**
* Wraps the value of iterator.next() in an option.
* Note: this facility is a part of the Iterator class starting from scala v2.13.
*
* @param iterator
* @tparam T the type of object held within the iterator
* @return Some(iterator.next) if a next element exists, None otherwise.
*/
private def nextOption[T](iterator: Iterator[T]): Option[T] = {
if (iterator.hasNext)
Some(iterator.next())
else
None
}
}
trait SegmentDeletionReason {
def logReason(toDelete: List[LogSegment]): Unit
}
case class LogTruncation(log: LocalLog) extends SegmentDeletionReason {
override def logReason(toDelete: List[LogSegment]): Unit = {
log.info(s"Deleting segments as part of log truncation: ${toDelete.mkString(",")}")
}
}
case class LogRoll(log: LocalLog) extends SegmentDeletionReason {
override def logReason(toDelete: List[LogSegment]): Unit = {
log.info(s"Deleting segments as part of log roll: ${toDelete.mkString(",")}")
}
}
case class LogDeletion(log: LocalLog) extends SegmentDeletionReason {
override def logReason(toDelete: List[LogSegment]): Unit = {
log.info(s"Deleting segments as the log has been deleted: ${toDelete.mkString(",")}")
}
}
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