Thanks for this insight. So the problem might be Flink using an internal
Kafka API (the connector uses reflection to get hold of the
TransactionManager) which changed between version 2.4.1 and 2.5. I think
this is a serious problem because it breaks our end-to-end exactly once
story when using new Kafka versions.
Cheers,
Till
On Thu, Jun 3, 2021 at 10:17 AM Tianxin Zhao <tiazhao...@gmail.com> wrote:
> I encountered the exact same issue before when experimenting in a testing
> environment. I was not able to spot the bug as mentioned in this thread,
> the solution I did was to downgrade my own kafka-client version from 2.5 to
> 2.4.1, matching the version of flink-connector-kafka.
> In 2.4.1 Kafka, TransactionManager is initializing producerIdAndEpoch using
>
> this.producerIdAndEpoch = new ProducerIdAndEpoch(NO_PRODUCER_ID,
>> NO_PRODUCER_EPOCH);
>
>
> instead of
>
>> this.producerIdAndEpoch = ProducerIdAndEpoch.NONE;
>
>
> On Thu, Jun 3, 2021 at 12:11 AM Till Rohrmann <trohrm...@apache.org>
> wrote:
>
>> Thanks for the update. Skimming over the code it looks indeed that we are
>> overwriting the values of the static value ProducerIdAndEpoch.NONE. I am
>> not 100% how this will cause the observed problem, though. I am also not a
>> Flink Kafka connector and Kafka expert so I would appreciate it if someone
>> more familiar could double check this part of the code.
>>
>> Concerning the required changing of the UID of an operator Piotr, is this
>> a known issue and documented somewhere? I find this rather surprising from
>> a user's point of view.
>>
>> Cheers,
>> Till
>>
>> On Thu, Jun 3, 2021 at 8:53 AM Till Rohrmann <trohrm...@apache.org>
>> wrote:
>>
>>> Forwarding 周瑞's message to a duplicate thread:
>>>
>>> After our analysis, we found a bug in the
>>> org.apache.flink.streaming.connectors.kafka.internals.FlinkKafkaInternalProducer.resumeTransaction
>>> method
>>> The analysis process is as follows：
>>>
>>>
>>> org.apache.flink.streaming.api.functions.sink.TwoPhaseCommitSinkFunction
>>> public void initializeState(FunctionInitializationContext context)
>>> throws Exception {
>>> state =
>>> context.getOperatorStateStore().getListState(stateDescriptor);
>>> boolean recoveredUserContext = false;
>>> if (context.isRestored()) {
>>> LOG.info("{} - restoring state", name());
>>> for (State<TXN, CONTEXT> operatorState : state.get()) {
>>> userContext = operatorState.getContext();
>>> List<TransactionHolder<TXN>> recoveredTransactions =
>>> operatorState.getPendingCommitTransactions();
>>> List<TXN> handledTransactions = new
>>> ArrayList<>(recoveredTransactions.size() + 1);
>>> for (TransactionHolder<TXN> recoveredTransaction :
>>> recoveredTransactions) {
>>> // If this fails to succeed eventually, there is
>>> actually data loss
>>> recoverAndCommitInternal(recoveredTransaction);
>>> handledTransactions.add(recoveredTransaction.handle);
>>> LOG.info("{} committed recovered transaction {}",
>>> name(), recoveredTransaction);
>>> }
>>>
>>> {
>>> TXN transaction =
>>> operatorState.getPendingTransaction().handle;
>>> recoverAndAbort(transaction);
>>> handledTransactions.add(transaction);
>>> LOG.info(
>>> "{} aborted recovered transaction {}",
>>> name(),
>>> operatorState.getPendingTransaction());
>>> }
>>>
>>> if (userContext.isPresent()) {
>>> finishRecoveringContext(handledTransactions);
>>> recoveredUserContext = true;
>>> }
>>> }
>>> }
>>>
>>> (1)recoverAndCommitInternal(recoveredTransaction);
>>> The previous transactionalid, producerId and epoch in the state are used
>>> to commit the transaction,However, we find that the producerIdAndEpoch of
>>> transactionManager is a static constant (ProducerIdAndEpoch.NONE), which
>>> pollutes the static constant ProducerIdAndEpoch.NONE
>>>
>>> @Override
>>> protected void recoverAndCommit(FlinkKafkaProducer.KafkaTransactionState
>>> transaction) {
>>> if (transaction.isTransactional()) {
>>> FlinkKafkaInternalProducer<byte[], byte[]> producer = null;
>>> try {
>>> producer =
>>> initTransactionalProducer(transaction.transactionalId, false);
>>> producer.resumeTransaction(transaction.producerId,
>>> transaction.epoch);
>>> producer.commitTransaction();
>>> } catch (InvalidTxnStateException | ProducerFencedException ex) {
>>> // That means we have committed this transaction before.
>>> LOG.warn(
>>> "Encountered error {} while recovering transaction
>>> {}. "
>>> + "Presumably this transaction has been
>>> already committed before",
>>> ex,
>>> transaction);
>>> } finally {
>>> if (producer != null) {
>>> producer.close(0, TimeUnit.SECONDS);
>>> }
>>> }
>>> }
>>> }
>>>
>>> public void resumeTransaction(long producerId, short epoch) {
>>> synchronized (producerClosingLock) {
>>> ensureNotClosed();
>>> Preconditions.checkState(
>>> producerId >= 0 && epoch >= 0,
>>> "Incorrect values for producerId %s and epoch %s",
>>> producerId,
>>> epoch);
>>> LOG.info(
>>> "Attempting to resume transaction {} with producerId {}
>>> and epoch {}",
>>> transactionalId,
>>> producerId,
>>> epoch);
>>>
>>> Object transactionManager = getField(kafkaProducer,
>>> "transactionManager");
>>> synchronized (transactionManager) {
>>> Object topicPartitionBookkeeper =
>>> getField(transactionManager,
>>> "topicPartitionBookkeeper");
>>>
>>> invoke(
>>> transactionManager,
>>> "transitionTo",
>>> getEnum(
>>>
>>> "org.apache.kafka.clients.producer.internals.TransactionManager$State.INITIALIZING"));
>>> invoke(topicPartitionBookkeeper, "reset");
>>>
>>> Object producerIdAndEpoch = getField(transactionManager,
>>> "producerIdAndEpoch");
>>> setField(producerIdAndEpoch, "producerId", producerId);
>>> setField(producerIdAndEpoch, "epoch", epoch);
>>>
>>> invoke(
>>> transactionManager,
>>> "transitionTo",
>>> getEnum(
>>>
>>> "org.apache.kafka.clients.producer.internals.TransactionManager$State.READY"));
>>>
>>> invoke(
>>> transactionManager,
>>> "transitionTo",
>>> getEnum(
>>>
>>> "org.apache.kafka.clients.producer.internals.TransactionManager$State.IN_TRANSACTION"));
>>> setField(transactionManager, "transactionStarted", true);
>>> }
>>> }
>>> }
>>>
>>>
>>> public TransactionManager(LogContext logContext,
>>> String transactionalId,
>>> int transactionTimeoutMs,
>>> long retryBackoffMs,
>>> ApiVersions apiVersions) {
>>> this.producerIdAndEpoch = ProducerIdAndEpoch.NONE;
>>> this.transactionalId = transactionalId;
>>> this.log = logContext.logger(TransactionManager.class);
>>> this.transactionTimeoutMs = transactionTimeoutMs;
>>> this.transactionCoordinator = null;
>>> this.consumerGroupCoordinator = null;
>>> this.newPartitionsInTransaction = new HashSet<>();
>>> this.pendingPartitionsInTransaction = new HashSet<>();
>>> this.partitionsInTransaction = new HashSet<>();
>>> this.pendingRequests = new PriorityQueue<>(10,
>>> Comparator.comparingInt(o -> o.priority().priority));
>>> this.pendingTxnOffsetCommits = new HashMap<>();
>>> this.partitionsWithUnresolvedSequences = new HashMap<>();
>>> this.partitionsToRewriteSequences = new HashSet<>();
>>> this.retryBackoffMs = retryBackoffMs;
>>> this.topicPartitionBookkeeper = new TopicPartitionBookkeeper();
>>> this.apiVersions = apiVersions;
>>> }
>>>
>>>
>>>
>>> public class ProducerIdAndEpoch {
>>> public static final ProducerIdAndEpoch NONE = new
>>> ProducerIdAndEpoch(RecordBatch.NO_PRODUCER_ID,
>>> RecordBatch.NO_PRODUCER_EPOCH);
>>>
>>> public final long producerId;
>>> public final short epoch;
>>>
>>> public ProducerIdAndEpoch(long producerId, short epoch) {
>>> this.producerId = producerId;
>>> this.epoch = epoch;
>>> }
>>>
>>> public boolean isValid() {
>>> return RecordBatch.NO_PRODUCER_ID < producerId;
>>> }
>>>
>>> @Override
>>> public String toString() {
>>> return "(producerId=" + producerId + ", epoch=" + epoch + ")";
>>> }
>>>
>>> @Override
>>> public boolean equals(Object o) {
>>> if (this == o) return true;
>>> if (o == null || getClass() != o.getClass()) return false;
>>>
>>> ProducerIdAndEpoch that = (ProducerIdAndEpoch) o;
>>>
>>> if (producerId != that.producerId) return false;
>>> return epoch == that.epoch;
>>> }
>>>
>>> @Override
>>> public int hashCode() {
>>> int result = (int) (producerId ^ (producerId >>> 32));
>>> result = 31 * result + (int) epoch;
>>> return result;
>>> }
>>>
>>> }
>>>
>>> （2）In the second step,
>>> recoverAndAbort(FlinkKafkaProducer.KafkaTransactionState transaction), when
>>> initializing the transaction, producerId and epoch in the first step
>>> pollute ProducerIdAndEpoch.NONE. Therefore, when an initialization request
>>> is sent to Kafka, the values of the producerId and epoch variables in the
>>> request parameter ProducerIdAndEpoch.NONE are equal to the values of the
>>> producerId and epoch variables in the first transaction commit, not equal
>>> to - 1, - 1. So Kafka throws an exception:
>>> Unexpected error in InitProducerIdResponse; Producer attempted an
>>> operation with an old epoch. Either there is a newer producer with the same
>>> transactionalId, or the producer's transaction has been expired by the
>>> broker.
>>> at
>>> org.apache.kafka.clients.producer.internals.TransactionManager$InitProducerIdHandler.handleResponse(TransactionManager.java:1352)
>>> at
>>> org.apache.kafka.clients.producer.internals.TransactionManager$TxnRequestHandler.onComplete(TransactionManager.java:1260)
>>> at
>>> org.apache.kafka.clients.ClientResponse.onComplete(ClientResponse.java:109)
>>> at
>>> org.apache.kafka.clients.NetworkClient.completeResponses(NetworkClient.java:572)
>>> at
>>> org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:564)
>>> at
>>> org.apache.kafka.clients.producer.internals.Sender.maybeSendAndPollTransactionalRequest(Sender.java:414)
>>> at
>>> org.apache.kafka.clients.producer.internals.Sender.runOnce(Sender.java:312)
>>> at
>>> org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:239)
>>> at java.lang.Thread.run(Thread.java:748)
>>>
>>> protected void recoverAndAbort(FlinkKafkaProducer.KafkaTransactionState
>>> transaction) {
>>> if (transaction.isTransactional()) {
>>> FlinkKafkaInternalProducer<byte[], byte[]> producer = null;
>>> try {
>>> producer =
>>> initTransactionalProducer(transaction.transactionalId, false);
>>> producer.initTransactions();
>>> } finally {
>>> if (producer != null) {
>>> producer.close(0, TimeUnit.SECONDS);
>>> }
>>> }
>>> }
>>> }
>>>
>>> public synchronized TransactionalRequestResult initializeTransactions() {
>>> return initializeTransactions(ProducerIdAndEpoch.NONE);
>>> }
>>>
>>> synchronized TransactionalRequestResult
>>> initializeTransactions(ProducerIdAndEpoch producerIdAndEpoch) {
>>> boolean isEpochBump = producerIdAndEpoch != ProducerIdAndEpoch.NONE;
>>> return handleCachedTransactionRequestResult(() -> {
>>> // If this is an epoch bump, we will transition the state as
>>> part of handling the EndTxnRequest
>>> if (!isEpochBump) {
>>> transitionTo(State.INITIALIZING);
>>> log.info("Invoking InitProducerId for the first time in
>>> order to acquire a producer ID");
>>> } else {
>>> log.info("Invoking InitProducerId with current producer ID
>>> and epoch {} in order to bump the epoch", producerIdAndEpoch);
>>> }
>>> InitProducerIdRequestData requestData = new
>>> InitProducerIdRequestData()
>>> .setTransactionalId(transactionalId)
>>> .setTransactionTimeoutMs(transactionTimeoutMs)
>>> .setProducerId(producerIdAndEpoch.producerId)
>>> .setProducerEpoch(producerIdAndEpoch.epoch);
>>> InitProducerIdHandler handler = new InitProducerIdHandler(new
>>> InitProducerIdRequest.Builder(requestData),
>>> isEpochBump);
>>> enqueueRequest(handler);
>>> return handler.result;
>>> }, State.INITIALIZING);
>>> }
>>>
>>> On Wed, Jun 2, 2021 at 3:55 PM Piotr Nowojski <pnowoj...@apache.org>
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> I think there is no generic way. If this error has happened indeed
>>>> after starting a second job from the same savepoint, or something like
>>>> that, user can change Sink's operator UID.
>>>>
>>>> If this is an issue of intentional recovery from an earlier
>>>> checkpoint/savepoint, maybe `FlinkKafkaProducer#setLogFailuresOnly` will be
>>>> helpful.
>>>>
>>>> Best, Piotrek
>>>>
>>>> wt., 1 cze 2021 o 15:16 Till Rohrmann <trohrm...@apache.org>
>>>> napisał(a):
>>>>
>>>>> The error message says that we are trying to reuse a transaction id
>>>>> that is
>>>>> currently being used or has expired.
>>>>>
>>>>> I am not 100% sure how this can happen. My suspicion is that you have
>>>>> resumed a job multiple times from the same savepoint. Have you checked
>>>>> that
>>>>> there is no other job which has been resumed from the same savepoint
>>>>> and
>>>>> which is currently running or has run and completed checkpoints?
>>>>>
>>>>> @pnowojski <pnowoj...@apache.org> @Becket Qin <becket....@gmail.com>
>>>>> how
>>>>> does the transaction id generation ensures that we don't have a clash
>>>>> of
>>>>> transaction ids if we resume the same job multiple times from the same
>>>>> savepoint? From the code, I do see that we have a
>>>>> TransactionalIdsGenerator
>>>>> which is initialized with the taskName and the operator UID.
>>>>>
>>>>> fyi: @Arvid Heise <ar...@apache.org>
>>>>>
>>>>> Cheers,
>>>>> Till
>>>>>
>>>>>
>>>>> On Mon, May 31, 2021 at 11:10 AM 周瑞 <rui.z...@woqutech.com> wrote:
>>>>>
>>>>> > HI:
>>>>> > When "sink.semantic = exactly-once", the following exception is
>>>>> > thrown when recovering from svaepoint
>>>>> >
>>>>> > public static final String KAFKA_TABLE_FORMAT =
>>>>> > "CREATE TABLE "+TABLE_NAME+" (\n" +
>>>>> > " "+COLUMN_NAME+" STRING\n" +
>>>>> > ") WITH (\n" +
>>>>> > " 'connector' = 'kafka',\n" +
>>>>> > " 'topic' = '%s',\n" +
>>>>> > " 'properties.bootstrap.servers' = '%s',\n" +
>>>>> > " 'sink.semantic' = 'exactly-once',\n" +
>>>>> > " 'properties.transaction.timeout.ms' =
>>>>> > '900000',\n" +
>>>>> > " 'sink.partitioner' =
>>>>> > 'com.woqutench.qmatrix.cdc.extractor.PkPartitioner',\n" +
>>>>> > " 'format' = 'dbz-json'\n" +
>>>>> > ")\n";
>>>>> > [] - Source: TableSourceScan(table=[[default_catalog,
>>>>> default_database,
>>>>> > debezium_source]], fields=[data]) -> Sink: Sink
>>>>> > (table=[default_catalog.default_database.KafkaTable], fields=[data])
>>>>> (1/1
>>>>> > )#859 (075273be72ab01bf1afd3c066876aaa6) switched from INITIALIZING
>>>>> to
>>>>> > FAILED with failure cause: org.apache.kafka.common.KafkaException:
>>>>> > Unexpected error in InitProducerIdResponse; Producer attempted an
>>>>> > operation with an old epoch. Either there is a newer producer with
>>>>> the
>>>>> > same transactionalId, or the producer's transaction has been expired
>>>>> by
>>>>> > the broker.
>>>>> > at org.apache.kafka.clients.producer.internals.
>>>>> >
>>>>> TransactionManager$InitProducerIdHandler.handleResponse(TransactionManager
>>>>> > .java:1352)
>>>>> > at org.apache.kafka.clients.producer.internals.
>>>>> >
>>>>> TransactionManager$TxnRequestHandler.onComplete(TransactionManager.java:
>>>>> > 1260)
>>>>> > at
>>>>> org.apache.kafka.clients.ClientResponse.onComplete(ClientResponse
>>>>> > .java:109)
>>>>> > at org.apache.kafka.clients.NetworkClient.completeResponses(
>>>>> > NetworkClient.java:572)
>>>>> > at
>>>>> org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:564)
>>>>> > at org.apache.kafka.clients.producer.internals.Sender
>>>>> > .maybeSendAndPollTransactionalRequest(Sender.java:414)
>>>>> > at
>>>>> org.apache.kafka.clients.producer.internals.Sender.runOnce(Sender
>>>>> > .java:312)
>>>>> > at
>>>>> org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:
>>>>> > 239)
>>>>> > at java.lang.Thread.run(Thread.java:748)
>>>>> >
>>>>>
>>>>
