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Posted to jira@kafka.apache.org by "Omkar Mestry (Jira)" <ji...@apache.org> on 2020/01/04 06:29:00 UTC
[jira] [Commented] (KAFKA-9259) suppress() for windowed-Serdes does
not work with default serdes
[ https://issues.apache.org/jira/browse/KAFKA-9259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17007928#comment-17007928 ]
Omkar Mestry commented on KAFKA-9259:
-------------------------------------
[~vvcephei] I went through code and found that in KStreamWindowAggregate, here in the process function the following code basically wraps the key with Windowed type :-
tupleForwarder.maybeForward(
new Windowed<>(key, entry.getValue()),
newAgg,
sendOldValues ? oldAgg : null,
newTimestamp);
> suppress() for windowed-Serdes does not work with default serdes
> ----------------------------------------------------------------
>
> Key: KAFKA-9259
> URL: https://issues.apache.org/jira/browse/KAFKA-9259
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.1.0
> Reporter: Matthias J. Sax
> Assignee: Omkar Mestry
> Priority: Major
> Labels: newbie
>
> The suppress() operator either inherits serdes from its upstream operator or falls back to default serdes from the config.
> If the upstream operator is an windowed aggregation, the window-aggregation operator wraps the user passed-in serde with a window-serde and pushed it into suppress() – however, if default serdes are used, the window-aggregation operator cannot push anything into suppress(). At runtime, it just creates a default serde and wraps it according. For this case, suppress() also falls back to default serdes; however, it does not wrap the serde and thus a ClassCastException is thrown when the serde is used later.
> suppress() is already aware if the upstream aggregation is time/session windowed or not and thus should use this information to wrap default serdes accordingly.
> The current workaround for windowed-suppress is to overwrite the default serde upstream to suppress(), such that suppress() inherits serdes and does not fall back to default serdes.
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