[
https://issues.apache.org/jira/browse/KAFKA-12775?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17343588#comment-17343588
]
A. Sophie Blee-Goldman commented on KAFKA-12775:
------------------------------------------------
If it's any consolation, I just so happen to be working on a way to isolate
independent parts of the topology to enable certain kinds of upgrades as we
speak. It's still very much in the experimental phase so no KIP yet, but
hopefully you won't have to wait too long. Until then, it's probably best to
play it safe as you said
> StreamsPartitionAssignor / ClientState throws an exception when a new Task
> gets added to a KStreams Application in a Backwards-Compatible Topology Change
> ---------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: KAFKA-12775
> URL: https://issues.apache.org/jira/browse/KAFKA-12775
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Reporter: Nico Habermann
> Priority: Major
>
> KAFKA-6145 and KAFKA-10079 added an [exception if the Partition Assignor
> tries to look up the lag for a TaskId that seemingly does not
> exist|https://github.com/apache/kafka/blob/trunk/streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/ClientState.java#L325].
>
> I believe this is a functional regression.
> Before, it was possible for Streams users to make backwards-compatible
> topology changes and roll those out, without having to do a complete restore
> or reload.
> For example:
> Existing sample topology:
>
> {code:java}
> stream1 = stream(topic)
> stream1
> .map(...)
> .to(output){code}
> And doing this backwards-compatible change:
> {code:java}
> stream1 = stream(topic)
> ++ table = stream(topic2).through(repartition-topic)/repartition().toTable()
> stream1
> .map(...)
> ++ .join(table)
> .to(output){code}
>
> This effectively creates a new subtopology with a new task for the table
> repartition.
> In older KStreams versions, it would have been possible to simply roll this
> change out.
> Since 2.6, rolling this out will crash the stream because the linked
> exception gets thrown when StreamsPartitionAssignor#getPreviousTasksByLag
> tries to look up the lag for the new table-repartition-task
>
> At this time, the only possible way to avoid this exception seems to be
> deleting all local state and doing a complete restore with the new topology
> change included.
>
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
