[ 
https://issues.apache.org/jira/browse/MAPREDUCE-5907?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Steve Loughran updated MAPREDUCE-5907:
--------------------------------------
    Labels:   (was: BB2015-05-TBR)

> Improve getSplits() performance for fs implementations that can utilize 
> performance gains from recursive listing
> ----------------------------------------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-5907
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5907
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: client
>    Affects Versions: 2.4.0
>            Reporter: Sumit Kumar
>            Assignee: Sumit Kumar
>            Priority: Major
>         Attachments: MAPREDUCE-5907-2.patch, MAPREDUCE-5907-3.patch, 
> MAPREDUCE-5907.patch
>
>
> FileInputFormat (both mapreduce and mapred implementations) use recursive 
> listing while calculating splits. They however do this by doing listing level 
> by level. That means to discover files in /foo/bar means they do listing at 
> /foo/bar first to get the immediate children, then make the same call on all 
> immediate children for /foo/bar to discover their immediate children and so 
> on. This doesn't scale well for object store based fs implementations like s3 
> and swift because every listStatus call ends up being a webservice call to 
> backend. In cases where large number of files are considered for input, this 
> makes getSplits() call slow. 
> This patch adds a new set of recursive list apis that gives opportunity to 
> the fs implementations to optimize. The behavior remains the same for other 
> implementations (that is a default implementation is provided for other fs so 
> they don't have to implement anything new). However for objectstore based fs 
> implementations it provides a simple change to include recursive flag as true 
> (as shown in the patch) to improve listing performance.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

---------------------------------------------------------------------
To unsubscribe, e-mail: mapreduce-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: mapreduce-issues-h...@hadoop.apache.org

Reply via email to