satishd commented on code in PR #13535:
URL: https://github.com/apache/kafka/pull/13535#discussion_r1186813113
##########
core/src/main/java/kafka/log/remote/RemoteLogManager.java:
##########
@@ -600,25 +622,208 @@ public String toString() {
}
}
- long findHighestRemoteOffset(TopicIdPartition topicIdPartition) throws
RemoteStorageException {
- Optional<Long> offset = Optional.empty();
- Optional<UnifiedLog> maybeLog =
fetchLog.apply(topicIdPartition.topicPartition());
- if (maybeLog.isPresent()) {
- UnifiedLog log = maybeLog.get();
- Option<LeaderEpochFileCache> maybeLeaderEpochFileCache =
log.leaderEpochCache();
- if (maybeLeaderEpochFileCache.isDefined()) {
- LeaderEpochFileCache cache = maybeLeaderEpochFileCache.get();
- OptionalInt epoch = cache.latestEpoch();
- while (!offset.isPresent() && epoch.isPresent()) {
- offset =
remoteLogMetadataManager.highestOffsetForEpoch(topicIdPartition,
epoch.getAsInt());
- epoch = cache.previousEpoch(epoch.getAsInt());
+ public FetchDataInfo read(RemoteStorageFetchInfo remoteStorageFetchInfo)
throws RemoteStorageException, IOException {
+ int fetchMaxBytes = remoteStorageFetchInfo.fetchMaxBytes;
+ TopicPartition tp = remoteStorageFetchInfo.topicPartition;
+ FetchRequest.PartitionData fetchInfo =
remoteStorageFetchInfo.fetchInfo;
+
+ boolean includeAbortedTxns = remoteStorageFetchInfo.fetchIsolation ==
FetchIsolation.TXN_COMMITTED;
+
+ long offset = fetchInfo.fetchOffset;
+ int maxBytes = Math.min(fetchMaxBytes, fetchInfo.maxBytes);
+
+ Optional<UnifiedLog> logOptional = fetchLog.apply(tp);
+ OptionalInt epoch = OptionalInt.empty();
+
+ if (logOptional.isPresent()) {
+ Option<LeaderEpochFileCache> leaderEpochCache =
logOptional.get().leaderEpochCache();
+ if (leaderEpochCache.isDefined()) {
+ epoch = leaderEpochCache.get().epochForOffset(offset);
+ }
+ }
+
+ Optional<RemoteLogSegmentMetadata> rlsMetadataOptional =
epoch.isPresent()
+ ? fetchRemoteLogSegmentMetadata(tp, epoch.getAsInt(), offset)
+ : Optional.empty();
+
+ if (!rlsMetadataOptional.isPresent()) {
+ String epochStr = (epoch.isPresent()) ?
Integer.toString(epoch.getAsInt()) : "NOT AVAILABLE";
+ throw new OffsetOutOfRangeException("Received request for offset "
+ offset + " for leader epoch "
+ + epochStr + " and partition " + tp + " which does not
exist in remote tier.");
+ }
+
+ RemoteLogSegmentMetadata remoteLogSegmentMetadata =
rlsMetadataOptional.get();
+ int startPos = lookupPositionForOffset(remoteLogSegmentMetadata,
offset);
+ InputStream remoteSegInputStream = null;
+ try {
+ // Search forward for the position of the last offset that is
greater than or equal to the target offset
+ remoteSegInputStream =
remoteLogStorageManager.fetchLogSegment(remoteLogSegmentMetadata, startPos);
+ RemoteLogInputStream remoteLogInputStream = new
RemoteLogInputStream(remoteSegInputStream);
+
+ RecordBatch firstBatch = findFirstBatch(remoteLogInputStream,
offset);
+
+ if (firstBatch == null)
+ return new FetchDataInfo(new LogOffsetMetadata(offset),
MemoryRecords.EMPTY, false,
+ includeAbortedTxns ?
Optional.of(Collections.emptyList()) : Optional.empty());
+
+ // An empty record is sent instead of an incomplete batch when
there is no minimum-one-message constraint
+ // and for FetchRequest version 3 and above and the first batch
size is more than maximum bytes that can be sent.
+ int firstBatchSize = firstBatch.sizeInBytes();
+ if (!remoteStorageFetchInfo.minOneMessage &&
+ !remoteStorageFetchInfo.hardMaxBytesLimit &&
+ firstBatchSize > maxBytes) {
+ return new FetchDataInfo(new LogOffsetMetadata(offset),
MemoryRecords.EMPTY);
+ }
+
+ int updatedFetchSize =
+ remoteStorageFetchInfo.minOneMessage && firstBatchSize >
maxBytes ? firstBatchSize : maxBytes;
+
+ ByteBuffer buffer = ByteBuffer.allocate(updatedFetchSize);
+ int remainingBytes = updatedFetchSize;
+
+ firstBatch.writeTo(buffer);
+ remainingBytes -= firstBatchSize;
+
+ if (remainingBytes > 0) {
+ // read the input stream until min of (EOF stream or buffer's
remaining capacity).
+ Utils.readFully(remoteSegInputStream, buffer);
+ }
+ buffer.flip();
+
+ FetchDataInfo fetchDataInfo = new FetchDataInfo(
+ new LogOffsetMetadata(offset,
remoteLogSegmentMetadata.startOffset(), startPos),
+ MemoryRecords.readableRecords(buffer));
+ if (includeAbortedTxns) {
+ fetchDataInfo =
addAbortedTransactions(firstBatch.baseOffset(), remoteLogSegmentMetadata,
fetchDataInfo, logOptional.get());
+ }
+
+ return fetchDataInfo;
+ } finally {
+ Utils.closeQuietly(remoteSegInputStream,
"RemoteLogSegmentInputStream");
+ }
+ }
+
+ private int lookupPositionForOffset(RemoteLogSegmentMetadata
remoteLogSegmentMetadata, long offset) {
+ return indexCache.lookupOffset(remoteLogSegmentMetadata, offset);
+ }
+
+ private FetchDataInfo addAbortedTransactions(long startOffset,
+ RemoteLogSegmentMetadata
segmentMetadata,
+ FetchDataInfo fetchInfo,
+ UnifiedLog log) throws
RemoteStorageException {
+ int fetchSize = fetchInfo.records.sizeInBytes();
+ OffsetPosition startOffsetPosition = new
OffsetPosition(fetchInfo.fetchOffsetMetadata.messageOffset,
+ fetchInfo.fetchOffsetMetadata.relativePositionInSegment);
+
+ OffsetIndex offsetIndex =
indexCache.getIndexEntry(segmentMetadata).offsetIndex();
+ long upperBoundOffset =
offsetIndex.fetchUpperBoundOffset(startOffsetPosition, fetchSize)
+ .map(x -> x.offset).orElse(segmentMetadata.endOffset() + 1);
+
+ final Set<FetchResponseData.AbortedTransaction> abortedTransactions =
new HashSet<>();
+
+ Consumer<List<AbortedTxn>> accumulator =
+ abortedTxns -> abortedTransactions.addAll(abortedTxns.stream()
+
.map(AbortedTxn::asAbortedTransaction).collect(Collectors.toList()));
+
+ collectAbortedTransactions(startOffset, upperBoundOffset,
segmentMetadata, accumulator, log);
+
+ return new FetchDataInfo(fetchInfo.fetchOffsetMetadata,
+ fetchInfo.records,
+ fetchInfo.firstEntryIncomplete,
+ Optional.of(abortedTransactions.isEmpty() ?
Collections.emptyList() : new ArrayList<>(abortedTransactions)));
+ }
+
+ private void collectAbortedTransactions(long startOffset,
+ long upperBoundOffset,
+ RemoteLogSegmentMetadata
segmentMetadata,
+ Consumer<List<AbortedTxn>>
accumulator,
+ UnifiedLog log) throws
RemoteStorageException {
+ Iterator<LogSegment> localLogSegments =
JavaConverters.asJavaIterator(log.logSegments().iterator());
+
+ boolean searchInLocalLog = false;
+ Optional<RemoteLogSegmentMetadata> nextSegmentMetadataOpt =
Optional.of(segmentMetadata);
+ Optional<TransactionIndex> txnIndexOpt =
nextSegmentMetadataOpt.map(metadata ->
indexCache.getIndexEntry(metadata).txnIndex());
+
+ while (txnIndexOpt.isPresent()) {
+ TxnIndexSearchResult searchResult =
txnIndexOpt.get().collectAbortedTxns(startOffset, upperBoundOffset);
+ accumulator.accept(searchResult.abortedTransactions);
+ if (!searchResult.isComplete) {
+ if (!searchInLocalLog) {
+ nextSegmentMetadataOpt =
findNextSegmentMetadata(nextSegmentMetadataOpt.get(), log);
+
+ txnIndexOpt = nextSegmentMetadataOpt.map(x ->
indexCache.getIndexEntry(x).txnIndex());
+ if (!txnIndexOpt.isPresent()) {
+ searchInLocalLog = true;
+ }
+ }
+
+ if (searchInLocalLog) {
+ txnIndexOpt = (localLogSegments.hasNext()) ?
Optional.of(localLogSegments.next().txnIndex()) : Optional.empty();
}
+ } else {
+ return;
+ }
+ }
+ }
+
+ private Optional<RemoteLogSegmentMetadata>
findNextSegmentMetadata(RemoteLogSegmentMetadata segmentMetadata, UnifiedLog
log) throws RemoteStorageException {
+ Option<LeaderEpochFileCache> leaderEpochFileCacheOption =
log.leaderEpochCache();
+ if (leaderEpochFileCacheOption.isEmpty()) {
+ return Optional.empty();
+ }
+
+ TopicPartition topicPartition =
segmentMetadata.topicIdPartition().topicPartition();
+ long nextSegmentBaseOffset = segmentMetadata.endOffset() + 1;
+ OptionalInt epoch =
OptionalInt.of(segmentMetadata.segmentLeaderEpochs().lastEntry().getKey());
Review Comment:
It initially tries to find a segment for that epoch and the offset. If that
is not found, it gets the next available epoch by using
`leaderEpochFileCache.nextEpoch(epoch.getAsInt())` and tries to find a segment
for that epoch. It eventually tries to find it by going through the epoch
sequence like below.
```
while (!result.isPresent() && epoch.isPresent()) {
result = fetchRemoteLogSegmentMetadata(topicPartition,
epoch.getAsInt(), nextSegmentBaseOffset);
epoch = leaderEpochFileCache.nextEpoch(epoch.getAsInt());
}
```
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