hadoop-mapreduce-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jason Lowe (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAPREDUCE-5268) Improve history server startup performance
Date Tue, 28 May 2013 20:05:21 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-5268?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13668616#comment-13668616
] 

Jason Lowe commented on MAPREDUCE-5268:
---------------------------------------

That will be fine, just making sure you were planning on getting something posted in the next
few days.  If something comes up and you won't get to it, I'd be happy to push it across the
finish line.  Thanks, Karthik!
                
> Improve history server startup performance
> ------------------------------------------
>
>                 Key: MAPREDUCE-5268
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5268
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: jobhistoryserver
>    Affects Versions: 0.23.7, 2.0.4-alpha
>            Reporter: Jason Lowe
>            Assignee: Karthik Kambatla
>
> The history server can easily take many minutes to startup when there are a significant
number of jobs to scan in the done directory.  However the scanning of files is not the bottleneck,
rather it's the heavy use of ConcurrentSkipListMap.size in HistoryFileManager.  
> ConcurrentSkipListMap.size is a very expensive operation, especially on maps with many
entries, as it has to scan every entry to compute the size.  We should avoid calling this
method or at least minimize its use.

--
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