[jira] [Commented] (KAFKA-9259) suppress() for windowed-Serdes does not work with default serdes

["highluck (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-9259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17245308#comment-17245308 ] 

highluck commented on KAFKA-9259:
---------------------------------

[~omanges] 
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> 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.
>  
> For the search engines, when using Avro, this results in a ClassCastException:
> {{Caused by: java.lang.ClassCastException: class org.apache.kafka.streams.kstream.Windowed cannot be cast to class org.apache.avro.specific.SpecificRecord (org.apache.kafka.streams.kstream.Windowed and org.apache.avro.specific.SpecificRecord are in unnamed module of loader 'app') at io.confluent.kafka.streams.serdes.avro.SpecificAvroSerializer.serialize(SpecificAvroSerializer.java:38)}}



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