hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Joydeep Sen Sarma (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-3155) reducers stuck at shuffling
Date Wed, 08 Oct 2008 16:57:44 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-3155?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12637983#action_12637983
] 

Joydeep Sen Sarma commented on HADOOP-3155:
-------------------------------------------

btw - one observation - failing the reduce task does not fix the problem. the restarted reducer
ends up hanging at precisely the same point (waiting for same N number of map-outputs - although
i can't tell if it's the exact same map-outputs - but it's the exact same 'N' all the time).
That makes me suspect that the issue is not a race condition (which was one of the possibilities
discussed in hadoop-4360).

> reducers stuck at shuffling 
> ----------------------------
>
>                 Key: HADOOP-3155
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3155
>             Project: Hadoop Core
>          Issue Type: Bug
>            Reporter: Runping Qi
>            Assignee: Amareshwari Sriramadasu
>         Attachments: events-job_200807311630_0007.txt, hadoop-3155-logs.tar.gz, jobevents_1007.txt,
patch-3155-debug-0.16.txt, patch-3155-debug-0.17.txt, task_200807311630_0007_r_000006_0.syslog.gz
>
>
> This happened with hadoop-0.16.2:
> In relatively small job (a few hundreds of mappers and reducers), reducers were stuck
at shuffling.
> I saw the lines like the following repeated hundreds of thousands of times over a few
hours:
> 2008-04-02 17:17:44,640 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:44,641 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:44,641 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:44,641 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:17:52,649 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:52,650 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:52,650 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:52,650 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:17:54,651 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:54,652 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:54,652 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:54,652 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:02,660 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:02,661 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:02,661 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:02,661 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:04,662 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:04,663 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:04,663 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:04,663 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:06,664 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:06,665 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:06,665 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:06,665 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:14,673 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:14,674 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:14,674 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:14,674 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:16,675 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:16,676 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:16,676 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:16,676 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...
> 2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
> 2008-04-02 17:18:22,682 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Need 2 map output(s)
> 2008-04-02 17:18:22,682 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0:
Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from
previous failures
> 2008-04-02 17:18:22,682 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0
Got 0 known map output location(s); scheduling...

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message