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

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.5.1
• Component/s: streams
• External issue URL: https://stackoverflow.com/questions/64945168/issue-with-kafkastreams-metadataforkey-in-particular-instance-alone
• Assignee: Unassigned
• Reporter: Maria Thomas
• Created: 11/Dec/20 10:56
• Updated: 24/Dec/20 11:12

Description

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.