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https://issues.apache.org/jira/browse/KAFKA-7930?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16767880#comment-16767880
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Murad M commented on KAFKA-7930:
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Historically those topics was auto-created as per GlobalKTable naming pattern.
Now they are being used for different purposes like cached lookup, which are
populated from various other places. And they effectively became "input" topics
represented as GlobalKTable. While there are mechanisms to re-populate them, it
does not necessarily mean that it has to be done every time application being
reset. For application reset it is enough to shift offsets to earliest, so that
GlobalKTable will materialize again from existing topic. It is true that, from
replay point of view, we would achieve different results, but same is true for
any other topic with 'cleanup.policy=compact,delete'. Some use-cases:
- static / managed configuration data (routes, flags etc.)
- caches pulled from external systems
- caches based on pushed from external systems
> StreamsResetter makes "changelog" topic naming assumptions
> ----------------------------------------------------------
>
> Key: KAFKA-7930
> URL: https://issues.apache.org/jira/browse/KAFKA-7930
> Project: Kafka
> Issue Type: Improvement
> Components: streams, tools
> Affects Versions: 2.1.0
> Reporter: Murad M
> Priority: Major
> Labels: features, needs-kip, patch-available, usability
>
> StreamsResetter deletes the topics considered internal. Currently it just
> checks the naming as per
> [code|https://github.com/apache/kafka/blob/1aae604861068bb7337d4972c9dcc0c0a99c374d/core/src/main/scala/kafka/tools/StreamsResetter.java#L660].
> If assumption is wrong (either topic prefix or suffix), tool becomes useless
> if aware even dangerous if not. Probably better either:
> * naming assumption should be optional and supply internal topics with
> argument (--internal-topics)
> * deletion could be optional (--no-delete-internal)
> * ignore topics which are included in list of --input-topics
> Faced this, when was trying to reset applications with GlobalKTable topics
> named as *-changelog. Such topics sometimes are not desirable for deletion.
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