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https://issues.apache.org/jira/browse/KAFKA-9259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16997533#comment-16997533
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Matthias J. Sax commented on KAFKA-9259:
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Consider KAFKA-9260, especially Guozhangs comment on it, it might be a good
idea to address KAFKA-9260 as it would resolve KAFKA-9248 and KAFKA-9259 at
once IMHO. When I create KAFKA-9260, it was unclear to me how it could be done,
but Guozhangs proposal makes a lot of sense to me. Of course, KAFKA-9260 would
require a KIP and the fix would only be available for future releases.
Hence, I am also fine if we just just `suppress()` directly, and also back port
the fix to 2.4 and 2.3, as KAFKA-9260 will only apply to 2.5...
> 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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