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KIP-479, implemented in Kafka 2.4.0, added StreamJoined to Kafka Streams as a way to extend features of Materialized to stream-stream joins. During the KIP discussion, adding options the option to disable caching and logging were discussed was but not implemented through KIP-479. Adding these features this feature allows users more flexibility over their store and fits with the original goal of extending Materialized features to stream-stream joins.

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This KIP will add the following four two methods as well as a loggingEnabled and cachingEnabled variables variable.

public StreamJoined<K, V1, V2> withLoggingEnabled(final WindowBytesStoreSupplier otherStoreSupplier) {}

public StreamJoined<K, V1, V2> withLoggingDisabled(final WindowBytesStoreSupplier otherStoreSupplier) {}

public StreamJoined<K, V1, V2> withCachingEnabled(final WindowBytesStoreSupplier otherStoreSupplier) {}

public StreamJoined<K, V1, V2> withCachingDisabled(final WindowBytesStoreSupplier otherStoreSupplier) {}

Proposed Changes

We will add four two new methods to StreamJoined to allow users to determine whether they want logging and caching for their stores. These configs set the caching and This config sets the logging decision for both stores, meaning that if logging is disabled for thisWindowStore, it will also be disabled for otherWindowStore. The default value for both loggingEnabled and cachingEnabled will for loggingEnabled will be true, enabling caching and logging for both stores if the user does not set the values manually.

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• Including withRetentionPeriod() → skipped as there is no reason for a user to configure a certain retention time for joins
• Including withCachingEnabled/Disabled → skipped because joins always retain duplicates which is incompatible with caching (see 

  Jira
  server ASF JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 5aa69414-a9e9-3523-82ec-879b028fb15b key KAFKA-9921

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