Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
Hadoop >> mail # user >> Reduce task hang[EMERGENCE]


Copy link to this message
-
Re: Reduce task hang[EMERGENCE]
Does the Reduce task log (of attempt_201312201200_34795_r_000000_0)
show any errors in trying to communicate with the various TaskTrackers
in trying to obtain the data?

On Fri, Jan 3, 2014 at 9:54 AM, Azuryy Yu <[EMAIL PROTECTED]> wrote:
> Add addtional:
>
> Our MR version is 1.2.1, not 1.0.4
>
> There is no useful information in the JT log.
>
>
> On Fri, Jan 3, 2014 at 12:20 PM, Azuryy Yu <[EMAIL PROTECTED]> wrote:
>>
>> Hi,
>>
>> Our prod cluster met some issues recently,
>> All map tasks finished successfully, but reduce task hanged.
>>
>> but It's not happened on all TaskTrackers, only sometimes. we used
>> mapred-1.0.4
>>
>> There is "0.0% reduce > copy >" forever until kill task manually.
>>
>> reduce logs on the TaskTracker:
>> hadoop-hadoop-tasktracker-10-200-91-186.out:14/01/03 06:13:57 INFO
>> mapred.TaskTracker: JVM with ID: jvm_201312201200_34795_r_-365330778 given
>> task: attempt_201312201200_34795_r_000000_0
>> hadoop-hadoop-tasktracker-10-200-91-186.out:14/01/03 06:14:04 INFO
>> mapred.TaskTracker: attempt_201312201200_34795_r_000000_0 0.0% reduce > copy
>> >
>> hadoop-hadoop-tasktracker-10-200-91-186.out:14/01/03 06:14:08 INFO
>> mapred.TaskTracker: attempt_201312201200_34795_r_000000_0 0.0% reduce > copy
>> >
>> hadoop-hadoop-tasktracker-10-200-91-186.out:14/01/03 06:14:14 INFO
>> mapred.TaskTracker: attempt_201312201200_34795_r_000000_0 0.0% reduce > copy
>> >
>> hadoop-hadoop-tasktracker-10-200-91-186.out:14/01/03 06:14:17 INFO
>> mapred.TaskTracker: attempt_201312201200_34795_r_000000_0 0.0% reduce > copy
>> >
>> hadoop-hadoop-tasktracker-10-200-91-186.out:14/01/03 06:14:23 INFO
>> mapred.TaskTracker: attempt_201312201200_34795_r_000000_0 0.0% reduce > copy
>> >
>
>

--
Harsh J