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https://issues.apache.org/jira/browse/KAFKA-6686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16787856#comment-16787856
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Antony Stubbs commented on KAFKA-6686:
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Also relates to KAFKA-6646 because if you want both a GTK and a KS from the
same topic, instead of KAFKA-6687, you could construct the GTK and then use
GTK#toStream...
> Allow reading topic as KStream and GlobalKTable
> -----------------------------------------------
>
> Key: KAFKA-6686
> URL: https://issues.apache.org/jira/browse/KAFKA-6686
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Matthias J. Sax
> Priority: Major
>
> 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
> {quote}Exception in thread “main”
> org.apache.kafka.streams.errors.TopologyException: Invalid topology: Topic
> source has already been registered by another source.
> {quote}
> 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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