[
https://issues.apache.org/jira/browse/KAFKA-3745?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15296991#comment-15296991
]
Guozhang Wang commented on KAFKA-3745:
--------------------------------------
[~gfodor] Actually can you share your join use cases where the {{ValueJoiner}}
itself needs to access the join key? Our original thought is that in many cases
the joiners do not depend on the specific join key values.
> Consider adding join key to ValueJoiner interface
> -------------------------------------------------
>
> Key: KAFKA-3745
> URL: https://issues.apache.org/jira/browse/KAFKA-3745
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Affects Versions: 0.10.0.0
> Reporter: Greg Fodor
> Priority: Minor
> Labels: api, newbie
>
> In working with Kafka Stream joining, it's sometimes the case that a join key
> is not actually present in the values of the joins themselves (if, for
> example, a previous transform generated an ephemeral join key.) In such
> cases, the actual key of the join is not available in the ValueJoiner
> implementation to be used to construct the final joined value. This can be
> worked around by explicitly threading the join key into the value if needed,
> but it seems like extending the interface to pass the join key along as well
> would be helpful.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
