junrao commented on a change in pull request #10763:
URL: https://github.com/apache/kafka/pull/10763#discussion_r659914342
##########
File path: core/src/main/scala/kafka/log/LogLoader.scala
##########
@@ -90,11 +90,63 @@ object LogLoader extends Logging {
* overflow index offset
*/
def load(params: LoadLogParams): LoadedLogOffsets = {
- // first do a pass through the files in the log directory and remove any
temporary files
+
+ // First pass: through the files in the log directory and remove any
temporary files
// and find any interrupted swap operations
val swapFiles = removeTempFilesAndCollectSwapFiles(params)
- // Now do a second pass and load all the log and index files.
+ // The remaining valid swap files must come from compaction or segment
split operation. We can
+ // simply rename them to regular segment files. But, before renaming, we
should figure out which
+ // segments are compacted and delete these segment files: this is done by
calculating min/maxSwapFileOffset.
+ // We store segments that require renaming in this code block, and do the
actual renaming later.
+ var minSwapFileOffset = Long.MaxValue
+ var maxSwapFileOffset = Long.MinValue
+ val toRenameSwapFiles = mutable.Set[File]()
+ swapFiles.filter(f => Log.isLogFile(new
File(CoreUtils.replaceSuffix(f.getPath, SwapFileSuffix, "")))).foreach { f =>
+ val baseOffset = offsetFromFile(f)
+ val segment = LogSegment.open(f.getParentFile,
+ baseOffset = baseOffset,
+ params.config,
+ time = params.time,
+ fileSuffix = Log.SwapFileSuffix)
+ toRenameSwapFiles += f
+ info(s"${params.logIdentifier}Found log file ${f.getPath} from
interrupted swap operation, which is recoverable from ${Log.SwapFileSuffix}
files by renaming.")
+ minSwapFileOffset = Math.min(segment.baseOffset, minSwapFileOffset)
+ maxSwapFileOffset = Math.max(segment.offsetIndex.lastOffset,
maxSwapFileOffset)
Review comment:
> I could be wrong, but I think if it is compaction, the last record
will never be removed. The reason is that compaction always removes earlier
records of each key, and the last record will never be an earlier one.
>
> Split should be similar.
It's true that we generally don't remove the last record during compaction.
However, during a round of cleaning, we clean segments in groups and each group
generates a single .clean file. The group is formed to make sure that offsets
are still within 2 billion in offset gap and the .clean file won't exceed 2GB
in size. If multiple groups are formed, it's possible that a group that's not
the last doesn't preserve the last record.
> How can we get the next segment before finishing the recovery process?
We could potentially scan all .log files and sort them in offset order.
##########
File path: core/src/main/scala/kafka/log/LogLoader.scala
##########
@@ -90,11 +90,58 @@ object LogLoader extends Logging {
* overflow index offset
*/
def load(params: LoadLogParams): LoadedLogOffsets = {
- // first do a pass through the files in the log directory and remove any
temporary files
+
+ // First pass: through the files in the log directory and remove any
temporary files
// and find any interrupted swap operations
val swapFiles = removeTempFilesAndCollectSwapFiles(params)
- // Now do a second pass and load all the log and index files.
+ // The remaining valid swap files must come from compaction or segment
split operation. We can
+ // simply rename them to regular segment files. But, before renaming, we
should figure out which
+ // segments are compacted and delete these segment files: this is done by
calculating min/maxSwapFileOffset.
Review comment:
"which segments are compacted": .swap files are also generated from
splitting.
##########
File path: core/src/main/scala/kafka/log/LogLoader.scala
##########
@@ -192,20 +230,10 @@ object LogLoader extends Logging {
debug(s"${params.logIdentifier}Deleting stray temporary file
${file.getAbsolutePath}")
Files.deleteIfExists(file.toPath)
} else if (filename.endsWith(CleanedFileSuffix)) {
- minCleanedFileOffset = Math.min(offsetFromFileName(filename),
minCleanedFileOffset)
- cleanFiles += file
+ minCleanedFileOffset = Math.min(offsetFromFile(file),
minCleanedFileOffset)
+ cleanedFiles += file
} else if (filename.endsWith(SwapFileSuffix)) {
- // we crashed in the middle of a swap operation, to recover:
- // if a log, delete the index files, complete the swap operation later
- // if an index just delete the index files, they will be rebuilt
- val baseFile = new File(CoreUtils.replaceSuffix(file.getPath,
SwapFileSuffix, ""))
- info(s"${params.logIdentifier}Found file ${file.getAbsolutePath} from
interrupted swap operation.")
- if (Log.isIndexFile(baseFile)) {
- deleteIndicesIfExist(baseFile)
- } else if (Log.isLogFile(baseFile)) {
- deleteIndicesIfExist(baseFile)
- swapFiles += file
- }
+ swapFiles += file
Review comment:
It's possible that during renaming, we have only renamed the .log file
to .swap, but not the corresponding index files. Should we find those .clean
files with the same offset and rename them to .swap?
##########
File path: core/src/main/scala/kafka/log/LogLoader.scala
##########
@@ -90,11 +90,58 @@ object LogLoader extends Logging {
* overflow index offset
*/
def load(params: LoadLogParams): LoadedLogOffsets = {
- // first do a pass through the files in the log directory and remove any
temporary files
+
+ // First pass: through the files in the log directory and remove any
temporary files
// and find any interrupted swap operations
val swapFiles = removeTempFilesAndCollectSwapFiles(params)
- // Now do a second pass and load all the log and index files.
+ // The remaining valid swap files must come from compaction or segment
split operation. We can
+ // simply rename them to regular segment files. But, before renaming, we
should figure out which
+ // segments are compacted and delete these segment files: this is done by
calculating min/maxSwapFileOffset.
+ // We store segments that require renaming in this code block, and do the
actual renaming later.
+ var minSwapFileOffset = Long.MaxValue
+ var maxSwapFileOffset = Long.MinValue
+ swapFiles.filter(f => Log.isLogFile(new
File(CoreUtils.replaceSuffix(f.getPath, SwapFileSuffix, "")))).foreach { f =>
+ val baseOffset = offsetFromFile(f)
+ val segment = LogSegment.open(f.getParentFile,
+ baseOffset = baseOffset,
+ params.config,
+ time = params.time,
+ fileSuffix = Log.SwapFileSuffix)
+ info(s"${params.logIdentifier}Found log file ${f.getPath} from
interrupted swap operation, which is recoverable from ${Log.SwapFileSuffix}
files by renaming.")
+ minSwapFileOffset = Math.min(segment.baseOffset, minSwapFileOffset)
+ maxSwapFileOffset = Math.max(segment.offsetIndex.lastOffset,
maxSwapFileOffset)
+ }
+
+ // Second pass: delete segments that are between minSwapFileOffset and
maxSwapFileOffset. As
+ // discussed above, these segments were compacted or split but haven't
been renamed to .delete
+ // before shutting down the broker.
+ for (file <- params.dir.listFiles if file.isFile) {
+ try {
+ if (!file.getName.endsWith(SwapFileSuffix)) {
+ val offset = offsetFromFile(file)
+ if (offset >= minSwapFileOffset && offset <= maxSwapFileOffset) {
Review comment:
If we use segment.nextOffset() to calculate maxSwapFileOffset, it's
exclusive.
##########
File path: core/src/main/scala/kafka/log/LogLoader.scala
##########
@@ -90,11 +90,63 @@ object LogLoader extends Logging {
* overflow index offset
*/
def load(params: LoadLogParams): LoadedLogOffsets = {
- // first do a pass through the files in the log directory and remove any
temporary files
+
+ // First pass: through the files in the log directory and remove any
temporary files
// and find any interrupted swap operations
val swapFiles = removeTempFilesAndCollectSwapFiles(params)
- // Now do a second pass and load all the log and index files.
+ // The remaining valid swap files must come from compaction or segment
split operation. We can
+ // simply rename them to regular segment files. But, before renaming, we
should figure out which
+ // segments are compacted and delete these segment files: this is done by
calculating min/maxSwapFileOffset.
+ // We store segments that require renaming in this code block, and do the
actual renaming later.
+ var minSwapFileOffset = Long.MaxValue
+ var maxSwapFileOffset = Long.MinValue
+ val toRenameSwapFiles = mutable.Set[File]()
+ swapFiles.filter(f => Log.isLogFile(new
File(CoreUtils.replaceSuffix(f.getPath, SwapFileSuffix, "")))).foreach { f =>
+ val baseOffset = offsetFromFile(f)
+ val segment = LogSegment.open(f.getParentFile,
+ baseOffset = baseOffset,
+ params.config,
+ time = params.time,
+ fileSuffix = Log.SwapFileSuffix)
+ toRenameSwapFiles += f
+ info(s"${params.logIdentifier}Found log file ${f.getPath} from
interrupted swap operation, which is recoverable from ${Log.SwapFileSuffix}
files by renaming.")
+ minSwapFileOffset = Math.min(segment.baseOffset, minSwapFileOffset)
+ maxSwapFileOffset = Math.max(segment.offsetIndex.lastOffset,
maxSwapFileOffset)
Review comment:
segment.offsetIndex.lastOffset doesn't give the exact last offset in a
segment since the index is sparse. We need to use segment.nextOffset().
##########
File path: core/src/test/scala/unit/kafka/log/LogCleanerTest.scala
##########
@@ -1472,11 +1489,30 @@ class LogCleanerTest {
time.scheduler.clear()
cleanedKeys = LogTestUtils.keysInLog(log)
- // 3) Simulate recovery after swap file is created and old segments files
are renamed
+ // 4) Simulate recovery after swap file is created and old segments files
are renamed
// to .deleted. Clean operation is resumed during recovery.
log.logSegments.head.changeFileSuffixes("", Log.SwapFileSuffix)
log = recoverAndCheck(config, cleanedKeys)
+ // add some more messages and clean the log again
+ while (log.numberOfSegments < 10) {
+ log.appendAsLeader(record(log.logEndOffset.toInt,
log.logEndOffset.toInt), leaderEpoch = 0)
+ messageCount += 1
+ }
+ for (k <- 1 until messageCount by 2)
+ offsetMap.put(key(k), Long.MaxValue)
+ cleaner.cleanSegments(log, log.logSegments.take(9).toSeq, offsetMap, 0L,
new CleanerStats(),
+ new CleanedTransactionMetadata)
+ // clear scheduler so that async deletes don't run
+ time.scheduler.clear()
+ cleanedKeys = LogTestUtils.keysInLog(log)
+
+ // 5) Simulate recovery after a subset of swap files are renamed to
regular files and old segments files are renamed
+ // to .deleted. Clean operation is resumed during recovery.
+ log.logSegments.head.timeIndex.file.renameTo(new
File(CoreUtils.replaceSuffix(log.logSegments.head.timeIndex.file.getPath, "",
Log.SwapFileSuffix)))
+ // .changeFileSuffixes("", Log.SwapFileSuffix)
Review comment:
Is this still needed?
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