akka.persistence.RecoveryTimedOut：恢复超时，没有'；无法在30000毫秒内获取快照

由于超时，我的测试失败。以下是我在日志输出中看到的内容：

2018-05-15 10:47:56.152 WARN  com.datastax.driver.core.NettyUtil [UserDataServiceSpec-cassandra-plugin-default-dispatcher-27] [] [] - Found Netty's native epoll transport, but not running on linux-based operating system. Using NIO instead.
2018-05-15 10:48:38.616 ERROR n.f.c.indexing.UniquelyIndexingActor [UserDataServiceSpec-akka.actor.default-dispatcher-39] [UserDataServiceSpec-akka.actor.default-dispatcher-29] [akka.tcp://UserDataServiceSpec@127.0.0.1:51627/user/$c/user-email-indexer] - Persistence failure when replaying events for persistenceId [user-email-indexer]. Last known sequence number [0]
akka.persistence.RecoveryTimedOut: Recovery timed out, didn't get snapshot within 30000 milliseconds
2018-05-15 10:48:38.617 ERROR a.c.sharding.PersistentShardCoordinator [UserDataServiceSpec-akka.actor.default-dispatcher-39] [UserDataServiceSpec-akka.actor.default-dispatcher-30] [akka.tcp://UserDataServiceSpec@127.0.0.1:51627/system/sharding/userdataCoordinator/singleton/coordinator] - Persistence failure when replaying events for persistenceId [/sharding/userdataCoordinator]. Last known sequence number [0]
akka.persistence.RecoveryTimedOut: Recovery timed out, didn't get snapshot within 30000 milliseconds
2018-05-15 10:48:38.618 INFO  akka.actor.LocalActorRef [UserDataServiceSpec-akka.actor.default-dispatcher-39] [UserDataServiceSpec-akka.actor.default-dispatcher-35] [akka://UserDataServiceSpec/user/$c/user-email-indexer] - Message [akka.persistence.SnapshotProtocol$LoadSnapshotFailed] from Actor[akka://UserDataServiceSpec/system/cassandra-snapshot-store#-750137778] to Actor[akka://UserDataServiceSpec/user/$c/user-email-indexer#1201357728] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
2018-05-15 10:48:38.619 INFO  akka.actor.LocalActorRef [UserDataServiceSpec-akka.actor.default-dispatcher-37] [UserDataServiceSpec-akka.actor.default-dispatcher-39] [akka://UserDataServiceSpec/system/sharding/userdataCoordinator/singleton/coordinator] - Message [akka.cluster.sharding.ShardCoordinator$RebalanceTick$] from Actor[akka://UserDataServiceSpec/system/sharding/userdataCoordinator/singleton/coordinator#-75387958] to Actor[akka://UserDataServiceSpec/system/sharding/userdataCoordinator/singleton/coordinator#-75387958] was not delivered. [2] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.

（不要问我为什么不使用内存存储来测试持久参与者。这与当前的问题无关。）

我对Akka和JVM没有经验，但我看到的消息只是“你搞砸了，伙计”。他们没有提示如何解决问题，也没有提示为什么会出现这种

RecoveryTimedOut

如果有人能给我一个有价值的建议如何诊断这个问题，那就太好了

---

UniquelyIndexingActor

被创建为集群单例

尝试将其添加到配置中：

akka {
  persistence {
    journal-plugin-fallback {
      recovery-event-timeout = 60s
    }
  }
}

它为我解决了问题。我在书中找到了它的参考资料