Spring Cloud Stream Kafka Streams健康指示器仅显示1个线程的疑问

我在Spring Boot中使用Spring Cloud Stream binder运行Kafka Streams应用，该应用包含多个实例，每个实例配置了4个线程（num.stream.threads=4）。但访问Actuator健康端点（/actuator/health）时，每个实例仅显示1个线程的详情。请问这是预期行为还是我配置有误？

这是否意味着在REST端点中使用InteractiveQueryService时，只能查询该单个线程所属的状态存储，实例中剩余的3个线程无法被访问？

更新信息 #

健康端点kstream部分输出 #

kstream: {
  status: "UP",
  details: {
    streams.job-part-index-v1-1-20230405-1: {
      adminClientId: "streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-admin",
      restoreConsumerClientId: "streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-4-restore-consumer",
      threadState: "RUNNING",
      producerClientIds: [
        "streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-4-producer"
      ],
      standbyTasks: { },
      activeTasks: {
        partitions: [
          "partition=13, topic=integration.access-control-job-part-v1-0",
          "partition=13, topic=integration.job-part-v1-0",
          "partition=13, topic=streams.job-part-index-v1-1-20230405-1-COGROUPKSTREAM-AGGREGATE-STATE-STORE-0000000006-repartition"
        ],
        taskId: {
          topicGroupId: 1,
          partition: 13
        }
      },
      consumerClientId: "streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-4-consumer",
      threadName: "streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-4"
    }
  }
}

运行日志（所有线程均正常运行） #

{"timestamp":"2023-05-22 06:56:57.654","level":"INFO","thread":"streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-1","logger":"org.apache.kafka.streams.processor.internals.StreamThread","message":"stream-thread [streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-1] Processed 262 total records, ran 8 punctuators, and committed 29 total tasks since the last update","context":"default"}
{"timestamp":"2023-05-22 06:57:29.502","level":"INFO","thread":"streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-2","logger":"org.apache.kafka.streams.processor.internals.StreamThread","message":"stream-thread [streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-2] Processed 280 total records, ran 4 punctuators, and committed 92 total tasks since the last update","context":"default"}
{"timestamp":"2023-05-22 06:58:15.243","level":"INFO","thread":"streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-3","logger":"org.apache.kafka.streams.processor.internals.StreamThread","message":"stream-thread [streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-3] Processed 78 total records, ran 0 punctuators, and committed 67 total tasks since the last update","context":"default"}
{"timestamp":"2023-05-22 06:58:15.628","level":"INFO","thread":"streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-4","logger":"org.apache.kafka.streams.processor.internals.StreamThread","message":"stream-thread [streams.job-part-index-v1-1-20230405-1-7a89107e-6487-47ef-b1b6-d249546b53ab-StreamThread-4] Processed 81 total records, ran 0 punctuators, and committed 72 total tasks since the last update","context":"default"}

环境：Spring Boot 2.6.6、Spring Cloud Stream 3.2.1；输入分区数大于总线程数。

1. 健康端点仅显示单个线程是否为预期行为？ #

这是预期行为，并非配置错误。

Spring Cloud Stream的Kafka Streams binder健康指示器默认只展示单个StreamThread的详情，因为健康检查的核心目标是确认应用整体运行状态正常，而非枚举所有线程的细节。只要Kafka Streams拓扑处于运行状态，健康状态就会标记为UP，其他线程依然在正常处理任务（你的运行日志已验证这一点）。

如果需要查看所有线程的完整状态，可以通过自定义健康指示器实现，遍历Kafka Streams实例的所有StreamThread并收集状态信息。

2. InteractiveQueryService能否访问实例中所有线程的状态存储？ #

完全可以，不会受健康端点显示内容的影响。

InteractiveQueryService基于Kafka Streams的元数据定位状态存储，会自动感知当前实例内所有线程持有的状态分区。当查询状态时，它会根据数据对应的分区，自动路由到当前实例中负责该分区的线程，无论健康端点是否展示了该线程的信息。也就是说，实例内4个线程对应的状态存储都可以正常访问，不存在只能查询单个线程存储的限制。

内容的提问来源于stack exchange，提问作者user2732824