hadoop-mapreduce-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Vinod Kumar Vavilapalli (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAPREDUCE-6251) JobClient needs additional retries at a higher level to address not-immediately-consistent dfs corner cases
Date Sat, 25 Apr 2015 00:44:39 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-6251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14512113#comment-14512113
] 

Vinod Kumar Vavilapalli commented on MAPREDUCE-6251:
----------------------------------------------------

It is not just getJob(). Clients may also make calls to isSuccessful() / getCounters() etc
and may run into the same failure. We should wrap them all up in a generic retry..

Does it also make sense for the server to throw a specific exception when this happens instead
of retrying everytime?

> JobClient needs additional retries at a higher level to address not-immediately-consistent
dfs corner cases
> -----------------------------------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-6251
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6251
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: jobhistoryserver, mrv2
>    Affects Versions: 2.6.0
>            Reporter: Craig Welch
>            Assignee: Craig Welch
>         Attachments: MAPREDUCE-6251.0.patch, MAPREDUCE-6251.1.patch, MAPREDUCE-6251.2.patch
>
>
> The JobClient is used to get job status information for running and completed jobs. 
Final state and history for a job is communicated from the application master to the job history
server via a distributed file system - where the history is uploaded by the application master
to the dfs and then scanned/loaded by the jobhistory server.  While HDFS has strong consistency
guarantees not all Hadoop DFS's do.  When used in conjunction with a distributed file system
which does not have this guarantee there will be cases where the history server may not see
an uploaded file, resulting in the dreaded "no such job" and a null value for the RunningJob
in the client.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message