hadoop-mapreduce-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Karthik Kambatla (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAPREDUCE-5110) Long task launch delays can lead to multiple parallel attempts of the task
Date Fri, 29 Mar 2013 05:51:17 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-5110?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13617104#comment-13617104
] 

Karthik Kambatla commented on MAPREDUCE-5110:
---------------------------------------------

To answer Arun's question in its entirety: Yes, it reverts MAPREDUCE-2217. MAPREDUCE-2217
was to address the case of hung TaskTracker. Till the time of this JIRA, we never observed
the current issue of the TT taking too long to start a task (which only seems to manifest
due to hardware issues). The current approach handles both scenarios.
                
> Long task launch delays can lead to multiple parallel attempts of the task
> --------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-5110
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5110
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: tasktracker
>    Affects Versions: 1.1.2
>            Reporter: Karthik Kambatla
>            Assignee: Karthik Kambatla
>         Attachments: expose-mr-5110.patch, mr-5110.patch, mr-5110.patch
>
>
> If a task takes too long to launch, the JT expires the task and schedules another attempt.
The earlier attempt can start after the later attempt leading to two parallel attempts running
at the same time. This is particularly an issue if the user turns off speculation and expects
a single attempt of a task to run at any point in time.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message