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https://issues.apache.org/jira/browse/MAPREDUCE-2349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13932566#comment-13932566
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Hadoop QA commented on MAPREDUCE-2349:
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{color:green}+1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12634271/MAPREDUCE-2349.4.txt
against trunk revision .
{color:green}+1 @author{color}. The patch does not contain any @author
tags.
{color:green}+1 tests included{color}. The patch appears to include 2 new
or modified test files.
{color:green}+1 javac{color}. The applied patch does not increase the
total number of javac compiler warnings.
{color:green}+1 javadoc{color}. There were no new javadoc warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with
eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new
Findbugs (version 1.3.9) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase
the total number of release audit warnings.
{color:green}+1 core tests{color}. The patch passed unit tests in
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core.
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/4417//testReport/
Console output:
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/4417//console
This message is automatically generated.
> speed up list[located]status calls from input formats
> -----------------------------------------------------
>
> Key: MAPREDUCE-2349
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-2349
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: task
> Reporter: Joydeep Sen Sarma
> Assignee: Siddharth Seth
> Attachments: MAPREDUCE-2349.1.wip.txt, MAPREDUCE-2349.2.txt,
> MAPREDUCE-2349.3.txt, MAPREDUCE-2349.4.txt
>
>
> when a job has many input paths - listStatus - or the improved
> listLocatedStatus - calls (invoked from the getSplits() method) can take a
> long time. Most of the time is spent waiting for the previous call to
> complete and then dispatching the next call.
> This can be greatly speeded up by dispatching multiple calls at once (via
> executors). If the same filesystem client is used - then the calls are much
> better pipelined (since calls are serialized) and don't impose extra burden
> on the namenode while at the same time greatly reducing the latency to the
> client. In a simple test on non-peak hours, this resulted in the getSplits()
> time reducing from about 3s to about 0.5s.
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