kafka-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (KAFKA-3561) Auto create through topic for KStream aggregation and join
Date Sat, 04 Jun 2016 15:22:59 GMT

    [ https://issues.apache.org/jira/browse/KAFKA-3561?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15315545#comment-15315545

ASF GitHub Bot commented on KAFKA-3561:

Github user dguy closed the pull request at:


> Auto create through topic for KStream aggregation and join
> ----------------------------------------------------------
>                 Key: KAFKA-3561
>                 URL: https://issues.apache.org/jira/browse/KAFKA-3561
>             Project: Kafka
>          Issue Type: Bug
>          Components: streams
>            Reporter: Guozhang Wang
>            Assignee: Damian Guy
>              Labels: api
>             Fix For:
> For KStream.join / aggregateByKey operations that requires the streams to be partitioned
on the record key, today users should repartition themselves through the "through" call:
> {code}
> stream1 = builder.stream("topic1");
> stream2 = builder.stream("topic2");
> stream3 = stream1.map(/* set the right key for join*/).through("topic3");
> stream4 = stream2.map(/* set the right key for join*/).through("topic4");
> stream3.join(stream4, ..)
> {code}
> This pattern can actually be done by the Streams DSL itself instead of requiring users
to specify themselves, i.e. users can just set the right key like (see KAFKA-3430) and then
call join, which will be translated by adding the "internal topic for repartition".
> Another thing is that today if user do not call "through" after setting a new key, the
aggregation result would not be correct as the aggregation is based on key B while the source
partitions is partitioned by key A and hence each task will only get a partial aggregation
for all keys. But this is not validated in the DSL today. We should do both the auto-translation
and validation.

This message was sent by Atlassian JIRA

View raw message