[jira] [Commented] (KAFKA-10843) Kafka Streams metadataForKey method returns null but allMetadata has the details

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

    [ https://issues.apache.org/jira/browse/KAFKA-10843?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17247886#comment-17247886 ] 

Bruno Cadonna commented on KAFKA-10843:
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[~maria_87] Thank you for the report!

{{allMetadata()}} returning a non-empty result and {{metadataForKey()}} returning {{null}} is indeed strange since they both read the information from the same member field. The result of that member field is updated during a rebalance. Could you try to call {{metadataForKey()}} after you observe that {{allMetadata()}} returns a non-empty result? Does it still return {{null}}? 

> Kafka Streams metadataForKey method returns null but allMetadata has the details
> --------------------------------------------------------------------------------
>
>                 Key: KAFKA-10843
>                 URL: https://issues.apache.org/jira/browse/KAFKA-10843
>             Project: Kafka
>          Issue Type: Bug
>          Components: streams
>    Affects Versions: 2.5.1
>            Reporter: Maria Thomas
>            Priority: Major
>
> Our application runs on multiple instances and to enable us to use get the key information from the state store we use "metadataForKey" method to retrieve the StreamMetadata and using the hostname do an RPC call to the host to get the value associated with the key.
> This call was working fine in our DEV and TEST environments, however, it is failing one our production clusters from the start. On further debugging, I noticed the allMetadata() method was returning the state stores with the host details as expected. However, it would not be feasible to go through each store explicitly to get the key details.
> To note, the cluster I am using is a stretch cluster.



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