无法使用Flink Processor API恢复检查点状态

Question

主程序是消费kafka事件，然后过滤-> map -> keyBy -> -> sink。我编写了另一个单独的简单程序来读取检查点目录，如下所示：

object StateReader extends App {

  val path = "file://...."

  val env = ExecutionEnvironment.getExecutionEnvironment

  val chk = Savepoint.load(env.getJavaEnv, path, new FsStateBackend(path))

  val ds = chk.readKeyedState("cep", new CepOperatorReadFunction, TypeInformation.of(classOf[KEY]), TypeInformation.of(classOf[VALUE]))
  println(ds.count())

}

class CepOperatorReadFunction extends KeyedStateReaderFunction[KEY, VALUE] {
  override def open(parameters: Configuration): Unit = {

  }
  override def readKey(k: KEY, context: KeyedStateReaderFunction.Context, collector: Collector[VALUE]): Unit = {

  }//end readKey
}//end class CepOperatorReadFunction

然而，我得到了以下异常：

Caused by: java.lang.IllegalStateException: Unexpected state handle type, expected: class org.apache.flink.runtime.state.KeyGroupsStateHandle, but found: class org.apache.flink.runtime.state.IncrementalRemoteKeyedStateHandle
    at org.apache.flink.runtime.state.heap.HeapRestoreOperation.restore(HeapRestoreOperation.java:120)
    at org.apache.flink.runtime.state.heap.HeapKeyedStateBackendBuilder.build(HeapKeyedStateBackendBuilder.java:114)
    ... 13 more

以下是flink-conf.yaml中的一些配置

state.backend: rocksdb
state.checkpoints.dir: hdfs:///.../checkpoints
state.savepoints.dir: hdfs:///.../savepoints
state.backend.incremental: true
state.backend.rocksdb.memory.write-buffer-ratio: 0.6
state.backend.rocksdb.localdir: /var/lib/.../rocksdb
execution.checkpointing.interval: 900000
execution.checkpointing.timeout: 600000
execution.checkpointing.unaligned: true
execution.checkpointing.mode: EXACTLY_ONCE
execution.checkpointing.max-concurrent-checkpoints: 1
execution.checkpointing.min-pause: 0

你知道为什么会发生异常以及如何解决这个问题吗？

谢谢

Answer 1

没有开箱即用的支持，无法轻松读取CEP操作员的状态。因此，要实现您的KeyedStateReaderFunction，您必须深入研究CEP实现，找到使用的ValueState和MapState，并实现一个使用这些状态描述符的读取器。