Apache Kafka® 3.1 is here with exciting new features and improvements! On behalf of the Kafka community, Danica Fine (Senior Developer Advocate, Confluent) shares release highlights that you won’t want to miss, including foreign-key joins in Kafka Streams and improvements that will provide consistency for Kafka latency metrics.
KAFKA-13439 deprecates the eager protocol, which has been the default since Kafka 2.4—it’s advised to upgrade your applications to the cooperative protocol as the eager protocol will no longer be supported in future releases. Previously, foreign-key joins in Kafka Streams only worked if both primary and foreign-key tables were joined. This release adds support for foreign-key joins on tables with custom partitioners, which will be passed in as part of a new `TableJoined` object, comparable to the existing `Joined` and `StreamJoined` objects.
With the goal of making Kafka more intuitive, KIP-773 enhances naming consistency for three new client metrics with millis and nanos. For example, `io-waittime-total` is reintroduced as `io-wait-time-ns-total`. The previously introduced metrics without ns will be deprecated but available for backward compatibility. KIP-768 continues the work started in KIP-255 to implement the necessary interfaces for a production-grade way to connect to an OpenID identity provider for authentication and token retrieval. This update provides an out-of-the-box implementation of an `AuthenticateCallbackHandler` that can be used to communicate with OAuth/OIDC.
Additionally, this Kafka release introduces two new metrics for active brokers specifically, `ActiveBrokerCount` and `FenceBrokerCount`. These two metrics expose the number of active brokers in the cluster known by the controller and the number of fenced brokers known by the controller.
Tune in to learn more about the Apache Kafka 3.1 release!
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