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https://issues.apache.org/jira/browse/HADOOP-3813?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12615993#action_12615993
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Amareshwari Sriramadasu commented on HADOOP-3813:
-------------------------------------------------

The code in JobInProgress.garbageCollect uses FileUtil.fullyDelete to delete 
the temporary directory, which is consuming time, during which Jobtracker is 
locked.
{code}
        FileSystem fileSys = tmpDir.getFileSystem(conf);
        if (fileSys.exists(tmpDir)) {
          FileUtil.fullyDelete(fileSys, tmpDir);
        }
{code}

I performed a delete on a directory with 1000 directories inside. It took few 
milli seconds with fs.delete(dir, true) and it took 2 minutes with 
FileUtil.fullDelete(FileSystem, dir).

The Jira HADOOP-3202 to deprecate FileUtil.fullyDelete is still open. 

> RPC queue overload of JobTracker
> --------------------------------
>
>                 Key: HADOOP-3813
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3813
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>    Affects Versions: 0.17.1
>            Reporter: Christian Kunz
>            Assignee: Amareshwari Sriramadasu
>
> On a cluster with about 1700 nodes, when a job with about 100,000 maps and 
> 10,000 reduces completed, the JobTracker, even with 80 handlers, could not 
> handle the rpc call load during promotion of the job, such that at the end, 
> because of the discarded heartbeats, the JobTracker lost nearly all 
> TaskTrackers (about 10 TaskTrackers left). Promotion took more than 40 
> minutes.
> They reconnected and everything recovered, but this might have been just luck.
> Shouldn't there be an adaptive throttling of the rate in heartbeats and 
> TaskCompletionEvents?
> Sample messsages:
> 2008-07-22 18:21:55,831 WARN org.apache.hadoop.ipc.Server: Call queue 
> overflow discarding oldest call heartbeat([EMAIL PROTECTED], false, true, 
> 18137) from xxx
> 2008-07-22 18:21:55,834WARN org.apache.hadoop.ipc.Server: Call queue overflow 
> discarding oldest call getTaskCompletionEvents(job_200807190635_0012, 119567, 
> 50) from yyy
> ...
> 2008-07-22 19:02:28,821 WARN org.apache.hadoop.ipc.Server: IPC Server handler 
> 1 on 9020, call heartbeat([EMAIL PROTECTED], false, true, 18199) from zzz: 
> discarded for being too old (40936)
> 2008-07-22 19:02:28,821 WARN org.apache.hadoop.ipc.Server: IPC Server handler 
> 34 on 9020, call getTaskCompletionEvents(job_200807190635_0012, 119567, 50) 
> from uuu: discarded for being too old (40978)

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