Cassandra：更改重试尝试次数和重试延迟

我正在使用客户端写入cassandra（api：com.datastax.driver.core）如果在连接完成后关闭cassandra clustures。我的日志中出现以下错误Cassandra：更改重试尝试次数和重试延迟

2015-11-05 12:08:21,667 ERROR [Reconnection-1] com.datastax.driver.core.ControlConnection - [Control connection] Cannot connect to any host, scheduling retry in 1000 milliseconds 
. 
. 
. 
2015-11-05 14:15:24,847 DEBUG [Reconnection-0] com.datastax.driver.core.Connection - Connection[/10.75.43.251:9042-24, inFlight=0, closed=false] Error connecting to /10.75.43.251:9042 (Connection refused: /10.75.43.251:9042) 
2015-11-05 14:15:24,847 DEBUG [Reconnection-0] com.datastax.driver.core.Connection - Defuncting connection to /10.75.43.251:9042 
com.datastax.driver.core.TransportException: [/10.75.43.251:9042] Cannot connect 
     at com.datastax.driver.core.Connection.<init>(Connection.java:104) 
     at com.datastax.driver.core.Connection$Factory.open(Connection.java:544) 
     at com.datastax.driver.core.Cluster$Manager$5.tryReconnect(Cluster.java:1652) 
     at com.datastax.driver.core.AbstractReconnectionHandler.run(AbstractReconnectionHandler.java:124) 
     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) 
     at java.util.concurrent.FutureTask.run(FutureTask.java:262) 
     at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178) 
     at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292) 
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 
     at java.lang.Thread.run(Thread.java:745) 
Caused by: java.net.ConnectException: Connection refused: /10.75.43.251:9042 
     at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) 
     at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.connect(NioClientBoss.java:150) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.processSelectedKeys(NioClientBoss.java:105) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.process(NioClientBoss.java:79) 
     at com.datastax.shaded.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:318) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.run(NioClientBoss.java:42) 
     at com.datastax.shaded.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) 
     at com.datastax.shaded.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42) 
     ... 3 more 


2015-11-05 14:15:24,847 DEBUG [New I/O worker #8] com.datastax.driver.core.Connection - Connection[/10.75.43.251:9042-24, inFlight=0, closed=true] closing connection 
2015-11-05 14:15:24,847 DEBUG [New I/O boss #9] com.datastax.driver.core.Connection - Connection[/10.75.43.251:9042-24, inFlight=0, closed=false] connection error 
java.net.ConnectException: Connection refused: /10.75.43.251:9042 
     at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) 
     at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.connect(NioClientBoss.java:150) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.processSelectedKeys(NioClientBoss.java:105) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.process(NioClientBoss.java:79) 
     at com.datastax.shaded.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:318) 
     at com.datastax.shaded.netty.channel.socket.nio.NioClientBoss.run(NioClientBoss.java:42) 
     at com.datastax.shaded.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) 
     at com.datastax.shaded.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42) 
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 
     at java.lang.Thread.run(Thread.java:745) 
2015-11-05 14:15:24,849 DEBUG [Reconnection-0] com.datastax.driver.core.Cluster - Failed reconnection to /10.75.43.251:9042 ([/10.75.43.251:9042] Cannot connect), scheduling retry in 600000 milliseconds 
2015-11-05 14:15:24,849 DEBUG [Cassandra Java Driver worker-44] com.datastax.driver.core.Cluster - Host /10.75.43.251:9042 is DOWN 
2015-11-05 14:15:24,849 DEBUG [Cassandra Java Driver worker-44] com.datastax.driver.core.Cluster - Aborting onDown because a reconnection is running on DOWN host /10.75.43.251:9042

我试着设置ReconnectionPolicy。这使我可以控制重试延迟。但是重试尝试（说我想要3）仍然不在我的控制之下。

我试图ConstantReconnectPolicy（其中仅给出reconnectDelay来提供，其中的工作。但我也希望重试被控制。我试图像

private volatile int currentRetryCount; 

    class MyReconnectionPolicy implements ReconnectionPolicy { 

     @Override 
     public ReconnectionSchedule newSchedule() { 
      return new MyReconnectionSchedule(); 

     } 
    } 

    class MyReconnectionSchedule implements ReconnectionSchedule { 

     @Override 
     public long nextDelayMs() { 
      if (++currentRetryCount < maxReconnectAttempts) { 
      return retryIntervalInMilliSec; 
      } else { 
       // try { 
       throw new Error("Exception Occurred. Retry limits exhausted."); 
       // } catch (Exception e) { 
       // logger.error("Exception Occurred!"); 
       // return Long.MAX_VALUE; 
       // } 
      } 
     } 

    }

某事，这也没有这个例外不会传播到主程序中，因为它不会抛出异常。

什么可能是api（如果暴露）或开放的bug（如果有的话，找不到）。

谢谢！

来源

2015-11-05 nandini

返回Long.MAX_VALUE计划未来的下一次重新连接尝试，这基本上与取消重新连接相同。虽然我会小心的，因为你最终可能会失去与所有节点的连接。

来源

2015-11-05 13:25:45

我试图关闭连接。但nextDelayMs（）方法不允许我抛出异常，因此在返回Long.MAX_VAL的catch中。 – nandini

不要抛出异常，直接返回值。 –

我解决了这个名字：

private class CustomExponentialSchedule implements ReconnectionSchedule { 

    private int attempts; 

    @Override 
    public long nextDelayMs() { 

     // If totalReconnectionCount is zero, the application won't be never stopped. 
     if (totalReconnectionCount != 0 && attempts == totalReconnectionCount) { 
      // Kill the Java process. 
      System.exit(1); 
     } 

     if (attempts > maxAttempts) { 
      return maxDelayMs; 
     } 

     return Math.min(baseDelayMs * (1L << attempts++), maxDelayMs); 
    } 
}

来源

2018-02-23 01:30:01

Cassandra：更改重试尝试次数和重试延迟

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