showuon commented on code in PR #12590: URL: https://github.com/apache/kafka/pull/12590#discussion_r969053802
########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/Fetcher.java: ########## @@ -1933,11 +1941,81 @@ private Map<String, String> topicPartitionTags(TopicPartition tp) { } } + // Visible for testing + void maybeCloseFetchSessions(final Timer timer) { + final Cluster cluster = metadata.fetch(); + final List<RequestFuture<ClientResponse>> requestFutures = new ArrayList<>(); + for (final Map.Entry<Integer, FetchSessionHandler> entry : sessionHandlers.entrySet()) { + final FetchSessionHandler sessionHandler = entry.getValue(); + // set the session handler to notify close. This will set the next metadata request to send close message. + sessionHandler.notifyClose(); + + final int sessionId = sessionHandler.sessionId(); + final Integer fetchTargetNodeId = entry.getKey(); + // FetchTargetNode may not be available as it may have disconnected the connection. In such cases, we will + // skip sending the close request. + final Node fetchTarget = cluster.nodeById(fetchTargetNodeId); + if (fetchTarget == null || client.isUnavailable(fetchTarget)) { + log.debug("Skip sending close session request to broker {} since it is not reachable", fetchTarget); + continue; + } + + log.debug("Sending close request for fetch session: {} to node: {}", sessionId, fetchTarget); + final RequestFuture<ClientResponse> responseFuture = sendFetchRequestToNode(sessionHandler.newBuilder().build(), fetchTarget); + responseFuture.addListener(new RequestFutureListener<ClientResponse>() { + @Override + public void onSuccess(ClientResponse value) { + log.info("Successfully sent a close message for fetch session: {} to node: {}", sessionId, fetchTarget); + } + + @Override + public void onFailure(RuntimeException e) { + log.info("Unable to a close message for fetch session: {} to node: {}. " + + "This may result in unnecessary fetch sessions at the broker.", sessionId, fetchTarget, e); + } + }); + + requestFutures.add(responseFuture); + } + + // Poll to ensure that request has been written to the socket. Wait until either the timer has expired or until + // all requests have received a response. + do { + client.poll(timer, null, true); + } while (timer.notExpired() && !requestFutures.stream().allMatch(RequestFuture::isDone)); + + if (!requestFutures.stream().allMatch(RequestFuture::isDone)) { + // we ran out of time before completing all futures. It is ok since we don't want to block the shutdown + // here. + log.warn("All requests couldn't be sent in the specific timeout period {}ms. " + + "This may result in unnecessary fetch sessions at the broker. Consider increasing the timeout passed for " + + "KafkaConsumer.close(Duration timeout)", timer.timeoutMs()); + } + } + + public void close(final Timer timer) { + if (isClosed.get()) { + log.info("Fetcher {} is already closed.", this); + return; + } + + // Shared states (e.g. sessionHandlers) could be accessed by multiple threads (such as heartbeat thread), hence, + // it is necessary to acquire a lock on the fetcher instance before modifying the states. + synchronized (Fetcher.this) { + // we do not need to re-enable wakeups since we are closing already + client.disableWakeups(); + if (nextInLineFetch != null) + nextInLineFetch.drain(); + maybeCloseFetchSessions(timer); + Utils.closeQuietly(decompressionBufferSupplier, "decompressionBufferSupplier"); + sessionHandlers.clear(); + } + this.isClosed.compareAndSet(false, true); Review Comment: I think we can set the `isClosed` earlier, so that it will not enter the synchronize block multiple times for different threads. ex: ```java if (this.isClosed.compareAndSet(false, true)) { // Shared states (e.g. sessionHandlers) could be accessed by multiple threads (such as heartbeat thread), hence, // it is necessary to acquire a lock on the fetcher instance before modifying the states. synchronized (Fetcher.this) { // we do not need to re-enable wakeups since we are closing already client.disableWakeups(); if (nextInLineFetch != null) nextInLineFetch.drain(); maybeCloseFetchSessions(timer); Utils.closeQuietly(decompressionBufferSupplier, "decompressionBufferSupplier"); sessionHandlers.clear(); } } else { log.info("Fetcher {} is already closed.", this); } ``` WDYT? ########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/Fetcher.java: ########## @@ -1933,11 +1941,81 @@ private Map<String, String> topicPartitionTags(TopicPartition tp) { } } + // Visible for testing + void maybeCloseFetchSessions(final Timer timer) { + final Cluster cluster = metadata.fetch(); + final List<RequestFuture<ClientResponse>> requestFutures = new ArrayList<>(); + for (final Map.Entry<Integer, FetchSessionHandler> entry : sessionHandlers.entrySet()) { + final FetchSessionHandler sessionHandler = entry.getValue(); + // set the session handler to notify close. This will set the next metadata request to send close message. + sessionHandler.notifyClose(); + + final int sessionId = sessionHandler.sessionId(); + final Integer fetchTargetNodeId = entry.getKey(); + // FetchTargetNode may not be available as it may have disconnected the connection. In such cases, we will + // skip sending the close request. + final Node fetchTarget = cluster.nodeById(fetchTargetNodeId); + if (fetchTarget == null || client.isUnavailable(fetchTarget)) { + log.debug("Skip sending close session request to broker {} since it is not reachable", fetchTarget); + continue; + } + + log.debug("Sending close request for fetch session: {} to node: {}", sessionId, fetchTarget); Review Comment: nit: I don't think this log is necessary, since we'll log in `sendFetchRequestToNode` later anyway. The output will looks duplicated like this: ``` Sending close request for fetch session: 1234 to node: 0 Sending request(...) uncommitted to broker 0 ``` ########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/Fetcher.java: ########## @@ -1933,11 +1941,81 @@ private Map<String, String> topicPartitionTags(TopicPartition tp) { } } + // Visible for testing + void maybeCloseFetchSessions(final Timer timer) { + final Cluster cluster = metadata.fetch(); + final List<RequestFuture<ClientResponse>> requestFutures = new ArrayList<>(); + for (final Map.Entry<Integer, FetchSessionHandler> entry : sessionHandlers.entrySet()) { + final FetchSessionHandler sessionHandler = entry.getValue(); + // set the session handler to notify close. This will set the next metadata request to send close message. + sessionHandler.notifyClose(); + + final int sessionId = sessionHandler.sessionId(); + final Integer fetchTargetNodeId = entry.getKey(); + // FetchTargetNode may not be available as it may have disconnected the connection. In such cases, we will + // skip sending the close request. + final Node fetchTarget = cluster.nodeById(fetchTargetNodeId); + if (fetchTarget == null || client.isUnavailable(fetchTarget)) { + log.debug("Skip sending close session request to broker {} since it is not reachable", fetchTarget); + continue; + } + + log.debug("Sending close request for fetch session: {} to node: {}", sessionId, fetchTarget); + final RequestFuture<ClientResponse> responseFuture = sendFetchRequestToNode(sessionHandler.newBuilder().build(), fetchTarget); + responseFuture.addListener(new RequestFutureListener<ClientResponse>() { + @Override + public void onSuccess(ClientResponse value) { + log.info("Successfully sent a close message for fetch session: {} to node: {}", sessionId, fetchTarget); Review Comment: nit: since we expected it'll succeed in most cases, maybe change this to `debug`? -- This is an automated message from the Apache Git Service. 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