adixitconfluent commented on code in PR #19437:
URL: https://github.com/apache/kafka/pull/19437#discussion_r2044029412
##########
core/src/main/java/kafka/server/share/DelayedShareFetch.java:
##########
@@ -529,8 +575,315 @@ Lock lock() {
return lock;
}
+ // Visible for testing.
+ RemoteFetch remoteFetch() {
+ return remoteFetchOpt.orElse(null);
+ }
+
// Visible for testing.
Meter expiredRequestMeter() {
return expiredRequestMeter;
}
+
+ private LinkedHashMap<TopicIdPartition, RemoteStorageFetchInfo>
maybePrepareRemoteStorageFetchInfo(
+ LinkedHashMap<TopicIdPartition, Long> topicPartitionData,
+ LinkedHashMap<TopicIdPartition, LogReadResult>
replicaManagerReadResponse
+ ) {
+ LinkedHashMap<TopicIdPartition, RemoteStorageFetchInfo>
remoteStorageFetchMetadataMap = new LinkedHashMap<>();
+ replicaManagerReadResponse.forEach((topicIdPartition, logReadResult)
-> {
+ if (logReadResult.info().delayedRemoteStorageFetch.isPresent()) {
+ remoteStorageFetchMetadataMap.put(topicIdPartition,
logReadResult.info().delayedRemoteStorageFetch.get());
+ partitionsAcquired.put(topicIdPartition,
topicPartitionData.get(topicIdPartition));
+ localPartitionsAlreadyFetched.put(topicIdPartition,
logReadResult);
+ }
+ });
+ return remoteStorageFetchMetadataMap;
+ }
+
+ private boolean maybeProcessRemoteFetch(
+ LinkedHashMap<TopicIdPartition, Long> topicPartitionData,
+ LinkedHashMap<TopicIdPartition, RemoteStorageFetchInfo>
remoteStorageFetchInfoMap,
+ LinkedHashMap<TopicIdPartition, LogReadResult>
replicaManagerReadResponse
+ ) throws Exception {
+ // topic partitions for which fetching would be happening from local
log and not remote storage.
+ Set<TopicIdPartition> localFetchTopicPartitions = new
LinkedHashSet<>();
+ topicPartitionData.keySet().forEach(topicIdPartition -> {
+ if (!remoteStorageFetchInfoMap.containsKey(topicIdPartition)) {
+ localFetchTopicPartitions.add(topicIdPartition);
+ }
+ });
+ // Release acquisition lock for the topic partitions that were
acquired but were not a part of remote fetch.
+ releasePartitionLocks(localFetchTopicPartitions);
+ Optional<Exception> exceptionOpt =
processRemoteFetchOrException(remoteStorageFetchInfoMap,
replicaManagerReadResponse);
+ if (exceptionOpt.isPresent()) {
+ remoteStorageFetchException = exceptionOpt;
+ throw exceptionOpt.get();
+ }
+ // Check if remote fetch can be completed.
+ return maybeCompletePendingRemoteFetch();
+ }
+
+ /**
+ * Returns an option containing an exception if a task for
RemoteStorageFetchInfo could not be scheduled successfully else returns empty
optional.
+ * @param remoteStorageFetchInfoMap - The topic partition to remote
storage fetch info map
+ */
+ private Optional<Exception> processRemoteFetchOrException(
+ LinkedHashMap<TopicIdPartition, RemoteStorageFetchInfo>
remoteStorageFetchInfoMap,
+ LinkedHashMap<TopicIdPartition, LogReadResult>
replicaManagerReadResponse
+ ) {
+ // TODO: There is a limitation in remote storage fetch for consumer
groups that we can only perform remote fetch for
+ // a single topic partition in a fetch request. Since, the logic of
fetch is largely based on how consumer groups work,
+ // we are following the same logic. However, this problem should be
addressed as part of KAFKA-19133 which should help us perform
+ // fetch for multiple remote fetch topic partition in a single share
fetch request
+ TopicIdPartition remoteFetchTopicIdPartition =
getRemoteFetchTopicIdPartition(remoteStorageFetchInfoMap);
+ RemoteStorageFetchInfo remoteStorageFetchInfo =
remoteStorageFetchInfoMap.get(remoteFetchTopicIdPartition);
+
+ LinkedHashMap<TopicIdPartition, LogOffsetMetadata>
fetchOffsetMetadataMap = new LinkedHashMap<>();
+ remoteStorageFetchInfoMap.forEach((topicIdPartition, logReadResult) ->
fetchOffsetMetadataMap.put(
+ topicIdPartition,
+
replicaManagerReadResponse.get(topicIdPartition).info().fetchOffsetMetadata
+ ));
+
+ Future<Void> remoteFetchTask;
+ CompletableFuture<RemoteLogReadResult> remoteFetchResult = new
CompletableFuture<>();
+ try {
+ remoteFetchTask =
replicaManager.remoteLogManager().get().asyncRead(
+ remoteStorageFetchInfo,
+ result -> {
+ remoteFetchResult.complete(result);
+ replicaManager.completeDelayedShareFetchRequest(new
DelayedShareFetchGroupKey(shareFetch.groupId(),
remoteFetchTopicIdPartition.topicId(),
remoteFetchTopicIdPartition.partition()));
+ }
+ );
+ } catch (RejectedExecutionException e) {
+ // Return the error if any in scheduling the remote fetch task.
+ log.warn("Unable to fetch data from remote storage", e);
+ return Optional.of(e);
+ } catch (Exception e) {
+ return Optional.of(e);
+ }
+ remoteFetchOpt = Optional.of(new
RemoteFetch(remoteFetchTopicIdPartition, remoteFetchTask, remoteFetchResult,
remoteStorageFetchInfo, fetchOffsetMetadataMap));
+ return Optional.empty();
+ }
+
+ /**
+ * This function returns the first topic partition for which we need to
perform remote storage fetch. We remove all the
+ * other partitions that can have a remote storage fetch for further
processing and release the fetch locks for them.
+ * @param remoteStorageFetchInfoMap map containing topic partition to
remote storage fetch information.
+ * @return the first topic partition for which we need to perform remote
storage fetch
+ */
+ private TopicIdPartition
getRemoteFetchTopicIdPartition(LinkedHashMap<TopicIdPartition,
RemoteStorageFetchInfo> remoteStorageFetchInfoMap) {
+ Map.Entry<TopicIdPartition, RemoteStorageFetchInfo>
firstRemoteStorageFetchInfo =
remoteStorageFetchInfoMap.entrySet().iterator().next();
+ TopicIdPartition remoteFetchTopicIdPartition =
firstRemoteStorageFetchInfo.getKey();
+ remoteStorageFetchInfoMap.keySet().forEach(topicIdPartition -> {
+ if (!topicIdPartition.equals(remoteFetchTopicIdPartition)) {
+ partitionsAcquired.remove(topicIdPartition);
+ releasePartitionLocks(Set.of(topicIdPartition));
+ }
+ });
+ return remoteFetchTopicIdPartition;
+ }
+
+ /**
+ * This function checks if the remote fetch can be completed or not. It
should always be called once you confirm remoteFetchOpt.isPresent().
+ * The operation can be completed if:
+ * Case a: The partition is in an offline log directory on this broker
+ * Case b: This broker does not know the partition it tries to fetch
+ * Case c: This broker is no longer the leader of the partition it tries
to fetch
+ * Case d: The remote storage read request completed (succeeded or failed)
+ * @return boolean representing whether the remote fetch is completed or
not.
+ */
+ private boolean maybeCompletePendingRemoteFetch() {
+ boolean canComplete = false;
+
+ for (Map.Entry<TopicIdPartition, LogOffsetMetadata> entry :
remoteFetchOpt.get().fetchOffsetMetadataMap().entrySet()) {
+ TopicIdPartition topicIdPartition = entry.getKey();
+ LogOffsetMetadata fetchOffsetMetadata = entry.getValue();
+ try {
+ if (fetchOffsetMetadata !=
LogOffsetMetadata.UNKNOWN_OFFSET_METADATA) {
+
replicaManager.getPartitionOrException(topicIdPartition.topicPartition());
+ }
+ } catch (KafkaStorageException e) { // Case a
+ log.debug("TopicPartition {} is in an offline log directory,
satisfy {} immediately", topicIdPartition, shareFetch.fetchParams());
+ canComplete = true;
+ } catch (UnknownTopicOrPartitionException e) { // Case b
+ log.debug("Broker no longer knows of topicPartition {},
satisfy {} immediately", topicIdPartition, shareFetch.fetchParams());
+ canComplete = true;
+ } catch (NotLeaderOrFollowerException e) { // Case c
+ log.debug("Broker is no longer the leader or follower of
topicPartition {}, satisfy {} immediately", topicIdPartition,
shareFetch.fetchParams());
+ canComplete = true;
+ }
+ if (canComplete)
+ break;
+ }
+
+ if (canComplete || remoteFetchOpt.get().remoteFetchResult().isDone())
{ // Case d
+ boolean completedByMe = forceComplete();
+ // If invocation of forceComplete is not successful, then that
means the request is already completed
+ // hence release the acquired locks.
+ if (!completedByMe) {
+ releasePartitionLocks(partitionsAcquired.keySet());
+ }
+ return completedByMe;
+ } else
+ return false;
+ }
+
+ /**
+ * This function completes a share fetch request for which we have
identified erroneous remote storage fetch in tryComplete()
+ * It should only be called when we know that there is remote fetch
in-flight/completed.
+ */
+ private void completeErroneousRemoteShareFetchRequest() {
+ try {
+ handleFetchException(shareFetch, partitionsAcquired.keySet(),
remoteStorageFetchException.get());
+ } finally {
+
releasePartitionLocksAndAddToActionQueue(partitionsAcquired.keySet());
+ }
+
+ }
+
+ private void
releasePartitionLocksAndAddToActionQueue(Set<TopicIdPartition>
topicIdPartitions) {
+ // Releasing the lock to move ahead with the next request in queue.
+ releasePartitionLocks(topicIdPartitions);
+ // If we have a fetch request completed for a topic-partition, we
release the locks for that partition,
+ // then we should check if there is a pending share fetch request for
the topic-partition and complete it.
+ // We add the action to delayed actions queue to avoid an infinite
call stack, which could happen if
+ // we directly call delayedShareFetchPurgatory.checkAndComplete
+ replicaManager.addToActionQueue(() ->
topicIdPartitions.forEach(topicIdPartition ->
+ replicaManager.completeDelayedShareFetchRequest(
+ new DelayedShareFetchGroupKey(shareFetch.groupId(),
topicIdPartition.topicId(), topicIdPartition.partition()))));
+ }
+
+ /**
+ * This function completes a share fetch request for which we have
identified remoteFetch during tryComplete()
+ * Note - This function should only be called when we know that there is
remote fetch in-flight/completed.
+ */
+ private void completeRemoteStorageShareFetchRequest() {
+ LinkedHashMap<TopicIdPartition, Long> nonRemoteFetchTopicPartitionData
= new LinkedHashMap<>();
+ try {
+ List<ShareFetchPartitionData> shareFetchPartitionData = new
ArrayList<>();
+ int readableBytes = 0;
+ if (remoteFetchOpt.get().remoteFetchResult().isDone()) {
+ RemoteFetch remoteFetch = remoteFetchOpt.get();
+ if (remoteFetch.remoteFetchResult().get().error.isPresent()) {
+ Throwable error =
remoteFetch.remoteFetchResult().get().error.get();
+ // If there is any error for the remote fetch topic
partition, we populate the error accordingly.
+ shareFetchPartitionData.add(
+ new ShareFetchPartitionData(
+ remoteFetch.topicIdPartition(),
+
partitionsAcquired.get(remoteFetch.topicIdPartition()),
+
ReplicaManager.createLogReadResult(error).toFetchPartitionData(false)
+ )
+ );
+ } else {
+ FetchDataInfo info =
remoteFetch.remoteFetchResult().get().fetchDataInfo.get();
+ TopicIdPartition topicIdPartition =
remoteFetch.topicIdPartition();
+ LogReadResult logReadResult =
localPartitionsAlreadyFetched.get(topicIdPartition);
+ shareFetchPartitionData.add(
+ new ShareFetchPartitionData(
+ topicIdPartition,
+
partitionsAcquired.get(remoteFetch.topicIdPartition()),
+ new FetchPartitionData(
+ logReadResult.error(),
+ logReadResult.highWatermark(),
+ logReadResult.leaderLogStartOffset(),
+ info.records,
+ Optional.empty(),
+ logReadResult.lastStableOffset().isDefined() ?
OptionalLong.of((Long) logReadResult.lastStableOffset().get()) :
OptionalLong.empty(),
+ info.abortedTransactions,
+
logReadResult.preferredReadReplica().isDefined() ? OptionalInt.of((Integer)
logReadResult.preferredReadReplica().get()) : OptionalInt.empty(),
+ false
+ )
+ )
+ );
+ readableBytes += info.records.sizeInBytes();
+ }
+ } else {
+ cancelRemoteFetchTask();
+ }
+
+ // If remote fetch bytes < shareFetch.fetchParams().maxBytes,
then we will try for a local read.
+ if (readableBytes < shareFetch.fetchParams().maxBytes) {
+ // Get the local log read based topic partitions.
+ LinkedHashMap<TopicIdPartition, SharePartition>
nonRemoteFetchSharePartitions = new LinkedHashMap<>();
+ sharePartitions.forEach((topicIdPartition, sharePartition) -> {
+ if (!partitionsAcquired.containsKey(topicIdPartition) &&
!remoteFetchOpt.get().fetchOffsetMetadataMap().containsKey(topicIdPartition)) {
+ nonRemoteFetchSharePartitions.put(topicIdPartition,
sharePartition);
+ }
+ });
+ nonRemoteFetchTopicPartitionData =
acquirablePartitions(nonRemoteFetchSharePartitions);
+ if (!nonRemoteFetchTopicPartitionData.isEmpty()) {
+ log.trace("Fetchable local share partitions for a remote
share fetch request data: {} with groupId: {} fetch params: {}",
+ nonRemoteFetchTopicPartitionData,
shareFetch.groupId(), shareFetch.fetchParams());
+
+ LinkedHashMap<TopicIdPartition, LogReadResult>
responseData = readFromLog(
+ nonRemoteFetchTopicPartitionData,
+
partitionMaxBytesStrategy.maxBytes(shareFetch.fetchParams().maxBytes -
readableBytes, nonRemoteFetchTopicPartitionData.keySet(),
nonRemoteFetchTopicPartitionData.size()));
+ for (Map.Entry<TopicIdPartition, LogReadResult> entry :
responseData.entrySet()) {
+ if
(entry.getValue().info().delayedRemoteStorageFetch.isEmpty()) {
+ shareFetchPartitionData.add(
+ new ShareFetchPartitionData(
+ entry.getKey(),
+
nonRemoteFetchTopicPartitionData.get(entry.getKey()),
+
entry.getValue().toFetchPartitionData(false)
+ )
+ );
+ }
+ }
+ }
+ }
+
+ // Update metric to record acquired to requested partitions.
+ double requestTopicToAcquired = (double)
(partitionsAcquired.size() + nonRemoteFetchTopicPartitionData.size()) /
shareFetch.topicIdPartitions().size();
+ if (requestTopicToAcquired > 0)
+
shareGroupMetrics.recordTopicPartitionsFetchRatio(shareFetch.groupId(), (int)
(requestTopicToAcquired * 100));
+
+ Map<TopicIdPartition, ShareFetchResponseData.PartitionData>
remoteFetchResponse = ShareFetchUtils.processFetchResponse(
+ shareFetch, shareFetchPartitionData, sharePartitions,
replicaManager, exceptionHandler);
+ shareFetch.maybeComplete(remoteFetchResponse);
+ log.trace("Remote share fetch request completed successfully,
response: {}", remoteFetchResponse);
+ } catch (RuntimeException e) {
+ throw e;
+ } catch (Exception e) {
+ log.error("Error processing delayed share fetch request", e);
+ Set<TopicIdPartition> topicIdPartitions = new
LinkedHashSet<>(partitionsAcquired.keySet());
+
topicIdPartitions.addAll(nonRemoteFetchTopicPartitionData.keySet());
+ handleFetchException(shareFetch, topicIdPartitions, e);
+ } finally {
+ Set<TopicIdPartition> topicIdPartitions = new
LinkedHashSet<>(partitionsAcquired.keySet());
+
topicIdPartitions.addAll(nonRemoteFetchTopicPartitionData.keySet());
+ releasePartitionLocksAndAddToActionQueue(topicIdPartitions);
+ }
+ }
+
+ /**
+ * Cancel the remote storage read task, if it has not been executed yet
and avoid interrupting the task if it is
+ * already running as it may force closing opened/cached resources as
transaction index.
+ * Note - This function should only be called when we know that there is a
remote fetch in-flight/completed.
+ */
+ private void cancelRemoteFetchTask() {
+ boolean cancelled =
remoteFetchOpt.get().remoteFetchTask().cancel(false);
+ if (!cancelled) {
+ log.debug("Remote fetch task for RemoteStorageFetchInfo: {} could
not be cancelled and its isDone value is {}",
+ remoteFetchOpt.get().remoteFetchInfo(),
remoteFetchOpt.get().remoteFetchTask().isDone());
+ }
+ }
+
+ public record RemoteFetch(
+ TopicIdPartition topicIdPartition,
+ Future<Void> remoteFetchTask,
+ CompletableFuture<RemoteLogReadResult> remoteFetchResult,
+ RemoteStorageFetchInfo remoteFetchInfo,
+ LinkedHashMap<TopicIdPartition, LogOffsetMetadata>
fetchOffsetMetadataMap
Review Comment:
we don't need to store `LogOffsetMetadata` now, hence I have removed
`fetchOffsetMetadataMap`.
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