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  1. Kafka
  2. KAFKA-6686

Allow reading topic as KStream and GlobalKTable

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: streams
    • Labels:
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      Description

      Users often want to read topic multiple times, eg, as a stream and a table. For KSteam/KTable this is possible by reading the data as a KTable, disable caching on the KTable, and get a stream via toStream(). This pattern does not work for KStream/GlobalKTable though.

      However, there is no need to raise an exception

      Exception in thread “main” org.apache.kafka.streams.errors.TopologyException: Invalid topology: Topic source has already been registered by another source.

      for this case, because the GlobalKTable is consumer by a different consumer (in contrast to KStream/KTable case for which KStream and KTable use a shared consumer). This fix should also allow to add a topic to a Topology twice; ie, one as regular and once as global-store topic.

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            • Assignee:
              Unassigned
              Reporter:
              mjsax Matthias J. Sax

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              • Created:
                Updated:

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