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https://issues.apache.org/jira/browse/HADOOP-5380?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12977487#action_12977487
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Kan Zhang commented on HADOOP-5380:
-----------------------------------
Just one quick observation. Currently, to close a connection that has already
been set up, all other threads would set the shouldCloseConnection flag by
calling markClosed() and the actual close() (cleanup) is done by the receiver
thread itself. Your current patch simply interrupts this thread. This may cause
it to bypass the cleanup.
> Calls from running tasks to TaskTracker methods sometimes fail and incur a
> 60s timeout
> --------------------------------------------------------------------------------------
>
> Key: HADOOP-5380
> URL: https://issues.apache.org/jira/browse/HADOOP-5380
> Project: Hadoop Common
> Issue Type: Bug
> Affects Versions: 0.20.1
> Reporter: Matei Zaharia
> Attachments: HADOOP-5380.Y.20.branch.patch
>
>
> I'm seeing some map tasks in my jobs take 1 minute to commit after they
> finish the map computation. On the map side, the output looks like this:
> <code>
> 2009-03-02 21:30:54,384 INFO org.apache.hadoop.metrics.jvm.JvmMetrics: Cannot
> initialize JVM Metrics with processName=MAP, sessionId= - already initialized
> 2009-03-02 21:30:54,437 INFO org.apache.hadoop.mapred.MapTask:
> numReduceTasks: 800
> 2009-03-02 21:30:54,437 INFO org.apache.hadoop.mapred.MapTask: io.sort.mb =
> 300
> 2009-03-02 21:30:55,493 INFO org.apache.hadoop.mapred.MapTask: data buffer =
> 239075328/298844160
> 2009-03-02 21:30:55,494 INFO org.apache.hadoop.mapred.MapTask: record buffer
> = 786432/983040
> 2009-03-02 21:31:00,381 INFO org.apache.hadoop.mapred.MapTask: Starting flush
> of map output
> 2009-03-02 21:31:07,892 INFO org.apache.hadoop.mapred.MapTask: Finished spill > 0
> 2009-03-02 21:31:07,951 INFO org.apache.hadoop.mapred.TaskRunner:
> Task:attempt_200903022127_0001_m_003163_0 is done. And is in the process of
> commiting
> 2009-03-02 21:32:07,949 INFO org.apache.hadoop.mapred.TaskRunner:
> Communication exception: java.io.IOException: Call to /127.0.0.1:50311 failed
> on local exception: java.nio.channels.ClosedChannelException
> at org.apache.hadoop.ipc.Client.wrapException(Client.java:765)
> at org.apache.hadoop.ipc.Client.call(Client.java:733)
> at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:220)
> at org.apache.hadoop.mapred.$Proxy0.ping(Unknown Source)
> at org.apache.hadoop.mapred.Task$TaskReporter.run(Task.java:525)
> at java.lang.Thread.run(Thread.java:619)
> Caused by: java.nio.channels.ClosedChannelException
> at
> java.nio.channels.spi.AbstractSelectableChannel.register(AbstractSelectableChannel.java:167)
> at
> java.nio.channels.SelectableChannel.register(SelectableChannel.java:254)
> at
> org.apache.hadoop.net.SocketIOWithTimeout$SelectorPool.select(SocketIOWithTimeout.java:331)
> at
> org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:157)
> at
> org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:155)
> at
> org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:128)
> at java.io.FilterInputStream.read(FilterInputStream.java:116)
> at
> org.apache.hadoop.ipc.Client$Connection$PingInputStream.read(Client.java:276)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
> at java.io.DataInputStream.readInt(DataInputStream.java:370)
> at
> org.apache.hadoop.ipc.Client$Connection.receiveResponse(Client.java:501)
> at org.apache.hadoop.ipc.Client$Connection.run(Client.java:446)
> 2009-03-02 21:32:07,953 INFO org.apache.hadoop.mapred.TaskRunner: Task
> 'attempt_200903022127_0001_m_003163_0' done.
> </code>
> In the TaskTracker log, it looks like this:
> <code>
> 2009-03-02 21:31:08,110 WARN org.apache.hadoop.ipc.Server: IPC Server
> Responder, call ping(attempt_200903022127_0001_m_003163_0) from
> 127.0.0.1:56884: output error
> 2009-03-02 21:31:08,111 INFO org.apache.hadoop.ipc.Server: IPC Server handler
> 10 on 50311 caught: java.nio.channels.ClosedChannelException
> at
> sun.nio.ch.SocketChannelImpl.ensureWriteOpen(SocketChannelImpl.java:126)
> at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:324) at
> org.apache.hadoop.ipc.Server.channelWrite(Server.java:1195)
> at org.apache.hadoop.ipc.Server.access$1900(Server.java:77)
> at org.apache.hadoop.ipc.Server$Responder.processResponse(Server.java:613)
> at org.apache.hadoop.ipc.Server$Responder.doRespond(Server.java:677)
> at org.apache.hadoop.ipc.Server$Handler.run(Server.java:981)
> </code>
> Note that the task actually seemed to commit - it didn't get speculatively
> executed or anything. However, the job wasn't able to continue until this one
> task was done. Both parties seem to think the channel was closed. How does
> the channel get closed externally? If closing it from outside is unavoidable,
> maybe the right thing to do is to set a much lower timeout, because 1 minute
> delay can be pretty significant for a small job.
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