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https://issues.apache.org/jira/browse/KAFKA-6614?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Matthias J. Sax reassigned KAFKA-6614:
--------------------------------------

    Assignee: Meghana Gupta

> kafka-streams to configure internal topics message.timestamp.type=CreateTime
> ----------------------------------------------------------------------------
>
>                 Key: KAFKA-6614
>                 URL: https://issues.apache.org/jira/browse/KAFKA-6614
>             Project: Kafka
>          Issue Type: Improvement
>          Components: streams
>            Reporter: Dmitry Vsekhvalnov
>            Assignee: Meghana Gupta
>            Priority: Minor
>              Labels: newbie
>
> After fixing KAFKA-4785 all internal topics using built-in 
> *RecordMetadataTimestampExtractor* to read timestamps.
> Which doesn't seem to work correctly out of box with kafka brokers configured 
> with *log.message.timestamp.type=LogAppendTime* when using custom message 
> timestamp extractor.
> Example use-case windowed grouping + aggregation on late data:
> {code:java}
> KTable<Windowed<Tuple>, Long> summaries = in
>    .groupBy((key, value) -> ......)
>    .windowedBy(TimeWindows.of(TimeUnit.HOURS.toMillis(1l)))
>    .count();{code}
> when processing late events:
>  # custom timestamp extractor will pick up timestamp in the past from message 
> (let's say hour ago)
>  # re-partition topic during grouping phase will be written back to kafka 
> using timestamp from (1)
>  # kafka broker will ignore provided timestamp in (2) to favor ingestion time
>  # streams lib will read re-partitioned topic back with 
> RecordMetadataTimestampExtractor
>  # and will get ingestion timestamp (3), which usually close to "now"
>  # window start/end will be incorrectly set based on "now" instead of 
> original timestamp from payload
> Understand there are ways to configure per-topic timestamp type in kafka 
> brokers to solve this, but it will be really nice if kafka-streams library 
> can take care of it itself.
> To follow "least-surprise" principle.  If library relies on timestamp.type 
> for topic it manages it should enforce it.
> CC [~guozhang] based on user group email discussion.



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