Error while handoff realtime data.

I get this error from time to time. But i can see that the segment was handed off fine. I’m just not sure if this is just a warning or should I be scare of?

I’m using Druid 0.9.0

2016-08-10T03:20:07,101 ERROR [coordinator_handoff_scheduled_0] io.druid.segment.realtime.plumber.CoordinatorBasedSegmentHandoffNotifier - Exception while checking handoff for dataSource[sparrow-firehose-web] Segment[SegmentDescriptor{interval=2016-08-10T02:00:00.000Z/2016-08-10T03:00:00.000Z, version='2016-08-10T02:00:00.291Z', partitionNumber=2}], Will try again after [60000]secs
java.lang.RuntimeException: java.util.concurrent.ExecutionException: org.jboss.netty.channel.ChannelException: Channel disconnected
at com.google.common.base.Throwables.propagate(Throwables.java:160) ~[guava-16.0.1.jar:?]
at io.druid.client.coordinator.CoordinatorClient.fetchServerView(CoordinatorClient.java:98) ~[druid-server-0.9.0.jar:0.9.0]
at io.druid.segment.realtime.plumber.CoordinatorBasedSegmentHandoffNotifier.checkForSegmentHandoffs(CoordinatorBasedSegmentHandoffNotifier.java:101) [druid-server-0.9.0.jar:0.9.0]
at io.druid.segment.realtime.plumber.CoordinatorBasedSegmentHandoffNotifier$1.run(CoordinatorBasedSegmentHandoffNotifier.java:86) [druid-server-0.9.0.jar:0.9.0]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [?:1.7.0_79]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304) [?:1.7.0_79]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:178) [?:1.7.0_79]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [?:1.7.0_79]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [?:1.7.0_79]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [?:1.7.0_79]
at java.lang.Thread.run(Thread.java:745) [?:1.7.0_79]
Caused by: java.util.concurrent.ExecutionException: org.jboss.netty.channel.ChannelException: Channel disconnected
at com.google.common.util.concurrent.AbstractFuture$Sync.getValue(AbstractFuture.java:299) ~[guava-16.0.1.jar:?]
at com.google.common.util.concurrent.AbstractFuture$Sync.get(AbstractFuture.java:286) ~[guava-16.0.1.jar:?]
at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:116) ~[guava-16.0.1.jar:?]
at io.druid.client.coordinator.CoordinatorClient.fetchServerView(CoordinatorClient.java:82) ~[druid-server-0.9.0.jar:0.9.0]
... 9 more
Caused by: org.jboss.netty.channel.ChannelException: Channel disconnected
at com.metamx.http.client.NettyHttpClient$1.channelDisconnected(NettyHttpClient.java:311) ~[http-client-1.0.4.jar:?]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:102) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.channelDisconnected(SimpleChannelUpstreamHandler.java:208) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:102) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.channelDisconnected(SimpleChannelUpstreamHandler.java:208) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:102) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.cleanup(ReplayingDecoder.java:570) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.handler.codec.frame.FrameDecoder.channelDisconnected(FrameDecoder.java:365) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:102) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleUpstream(HttpClientCodec.java:92) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.Channels.fireChannelDisconnected(Channels.java:396) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.close(AbstractNioWorker.java:360) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:93) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:108) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:337) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) ~[netty-3.10.4.Final.jar:?]
at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42) ~[netty-3.10.4.Final.jar:?]
... 3 more
Host: ip-10-90-45-80.ec2.internal
Name: /var/log/druid.log
Category: production-druid
dummy: ERROR

Hi,

After handoff of data, the task periodically polls the coordinator for the status of handoff.

If the status check fails, the task retries at 1 minute intervals, so it should be harmless for transient errors like above.