[ 
https://issues.apache.org/jira/browse/FLINK-16419?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17448680#comment-17448680
 ] 

Fabian Paul commented on FLINK-16419:
-------------------------------------

Thanks for the additional information. I think we should continue the 
discussion on a new ticket because the problems seem to be unrelated to this 
one.

One thing to note is that we deprecated the FlinkKafkaProducer with Flink 1.14 
and introduced the KafkaSink that uses a different transaction management model 
and does not reuse the transactions id.

It would be great to have a simple test case showing this problem. AFAICT 
having a low transaction pool size with a high timeout should give the case you 
are describing. 

[~qzhzm173227] can you work on this?

 

> Avoid to recommit transactions which are known committed successfully to 
> Kafka upon recovery
> --------------------------------------------------------------------------------------------
>
>                 Key: FLINK-16419
>                 URL: https://issues.apache.org/jira/browse/FLINK-16419
>             Project: Flink
>          Issue Type: Improvement
>          Components: Connectors / Kafka, Runtime / Checkpointing
>            Reporter: Jun Qin
>            Priority: Minor
>              Labels: auto-deprioritized-major, stale-minor, usability
>
> When recovering from a snapshot (checkpoint/savepoint), FlinkKafkaProducer 
> tries to recommit all pre-committed transactions which are in the snapshot, 
> even if those transactions were successfully committed before (i.e., the call 
> to {{kafkaProducer.commitTransaction()}} via {{notifyCheckpointComplete()}} 
> returns OK). This may lead to recovery failures when recovering from a very 
> old snapshot because the transactional IDs in that snapshot may have been 
> expired and removed from Kafka.  For example the following scenario:
>  # Start a Flink job with FlinkKafkaProducer sink with exactly-once
>  # Suspend the Flink job with a savepoint A
>  # Wait for time longer than {{transactional.id.expiration.ms}} + 
> {{transaction.remove.expired.transaction.cleanup.interval.ms}}
>  # Recover the job with savepoint A.
>  # The recovery will fail with the following error:
> {noformat}
> 2020-02-26 14:33:25,817 INFO  
> org.apache.flink.streaming.connectors.kafka.internal.FlinkKafkaInternalProducer
>   - Attempting to resume transaction Source: Custom Source -> Sink: 
> Unnamed-7df19f87deec5680128845fd9a6ca18d-1 with producerId 2001 and epoch 
> 1202020-02-26 14:33:25,914 INFO  org.apache.kafka.clients.Metadata            
>                 - Cluster ID: RN0aqiOwTUmF5CnHv_IPxA
> 2020-02-26 14:33:26,017 INFO  org.apache.kafka.clients.producer.KafkaProducer 
>              - [Producer clientId=producer-1, transactionalId=Source: Custom 
> Source -> Sink: Unnamed-7df19f87deec5680128845fd9a6ca18d-1] Closing the Kafka 
> producer with timeoutMillis = 92233720
> 36854775807 ms.
> 2020-02-26 14:33:26,019 INFO  org.apache.flink.runtime.taskmanager.Task       
>              - Source: Custom Source -> Sink: Unnamed (1/1) 
> (a77e457941f09cd0ebbd7b982edc0f02) switched from RUNNING to FAILED.
> org.apache.kafka.common.KafkaException: Unhandled error in EndTxnResponse: 
> The producer attempted to use a producer id which is not currently assigned 
> to its transactional id.
>         at 
> org.apache.kafka.clients.producer.internals.TransactionManager$EndTxnHandler.handleResponse(TransactionManager.java:1191)
>         at 
> org.apache.kafka.clients.producer.internals.TransactionManager$TxnRequestHandler.onComplete(TransactionManager.java:909)
>         at 
> org.apache.kafka.clients.ClientResponse.onComplete(ClientResponse.java:109)
>         at 
> org.apache.kafka.clients.NetworkClient.completeResponses(NetworkClient.java:557)
>         at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:549)
>         at 
> org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:288)
>         at 
> org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:235)
>         at java.lang.Thread.run(Thread.java:748)
> {noformat}
> For now, the workaround is to call 
> {{producer.ignoreFailuresAfterTransactionTimeout()}}. This is a bit risky, as 
> it may hide real transaction timeout errors. 
> After discussed with [~becket_qin], [~pnowojski] and [~aljoscha], a possible 
> way is to let JobManager, after successfully notifies all operators the 
> completion of a snapshot (via {{notifyCheckpoingComplete}}), record the 
> success, e.g., write the successful transactional IDs somewhere in the 
> snapshot. Then those transactions need not recommit upon recovery.



--
This message was sent by Atlassian Jira
(v8.20.1#820001)

Reply via email to