[
https://issues.apache.org/jira/browse/KAFKA-8671?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16891467#comment-16891467
]
Guozhang Wang commented on KAFKA-8671:
--------------------------------------
*(typing too fast)* As for the issue itself, I think the idea of KAFKA-5998
could still be applied: when reading from the checkpoint file, if the
corresponding topic is no longer in our interested changelog topic list, we
should filter it out in our assigned partitions of the restore.consumer.
> NullPointerException occurs if topic associated with GlobalKTable changes
> -------------------------------------------------------------------------
>
> Key: KAFKA-8671
> URL: https://issues.apache.org/jira/browse/KAFKA-8671
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.0.0, 2.1.0, 2.2.0, 2.3.0
> Reporter: Alex Leung
> Assignee: Alex Leung
> Priority: Critical
>
> The following NullPointerException occurs when the global/.checkpoint file
> contains a line with a topic previously associated with (but no longer
> configured for) a GlobalKTable:
> {code:java}
> java.lang.NullPointerException
> at
> org.apache.kafka.streams.processor.internals.GlobalStateUpdateTask.update(GlobalStateUpdateTask.java:85)
> at
> org.apache.kafka.streams.processor.internals.GlobalStreamThread$StateConsumer.pollAndUpdate(GlobalStreamThread.java:241)
> at
> org.apache.kafka.streams.processor.internals.GlobalStreamThread.run(GlobalStreamThread.java:290){code}
>
> After line 84
> ([https://github.com/apache/kafka/blob/2.0/streams/src/main/java/org/apache/kafka/streams/processor/internals/GlobalStateUpdateTask.java#L84)]
> `sourceNodeAndDeserializer` is null for the old, but still valid, topic.
> This can be reproduced with the following sequence:
> # create a GlobalKTable associated with topic, 'global-topic1'
> # change the topic associated with the GlobalKTable to 'global-topic2'
> ## at this point, the global/.checkpoint file will contain lines for both
> topics
> # produce messages to previous topic ('global-topic1')
> # the consumer will attempt to consume from global-topic1, but no
> deserializer associated with global-topic1 will be found and the NPE will
> occur
> It looks like the following recent commit has included checkpoint validations
> that may prevent this issue:
> https://github.com/apache/kafka/commit/53b4ce5c00d61be87962f603682873665155cec4#diff-cc98a6c20f2a8483e1849aea6921c34dR425
--
This message was sent by Atlassian JIRA
(v7.6.14#76016)
