KIP-67 — Queryable state for Kafka Streams

Accepted Streams

Introduces Interactive Queries (IQ) in Kafka Streams, exposing read-only access to local state stores (key-value, windowed, session) via KafkaStreams.store() and making store host metadata discoverable via KafkaStreams.allMetadataForStore() for cross-instance routing. Application state was previously fully encapsulated inside Streams tasks with no supported API for external querying, forcing developers to duplicate state into external databases.

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