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https://issues.apache.org/jira/browse/MAPREDUCE-4907?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13549246#comment-13549246
]
Hadoop QA commented on MAPREDUCE-4907:
--------------------------------------
{color:green}+1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12564062/MAPREDUCE-4907-trunk-1.patch
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 1 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}. The javadoc tool did not generate any
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/3225//testReport/
Console output:
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/3225//console
This message is automatically generated.
> TrackerDistributedCacheManager issues too many getFileStatus calls
> ------------------------------------------------------------------
>
> Key: MAPREDUCE-4907
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4907
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: mrv1, tasktracker
> Affects Versions: 1.1.1
> Reporter: Sandy Ryza
> Assignee: Sandy Ryza
> Attachments: MAPREDUCE-4907.patch, MAPREDUCE-4907-trunk-1.patch,
> MAPREDUCE-4907-trunk-1.patch, MAPREDUCE-4907-trunk-1.patch,
> MAPREDUCE-4907-trunk.patch
>
>
> TrackerDistributedCacheManager issues a number of redundant getFileStatus
> calls when determining the timestamps and visibilities of files in the
> distributed cache. 300 distributed cache files deep in the directory
> structure can hammer HDFS with a couple thousand requests.
> A couple optimizations can reduce this load:
> 1. determineTimestamps and determineCacheVisibilities both call getFileStatus
> on every file. We could cache the results of the former and use them for the
> latter.
> 2. determineCacheVisibilities needs to check that all ancestor directories of
> each file have execute permissions for everyone. This currently entails a
> getFileStatus on each ancestor directory for each file. The results of these
> getFileStatus calls could be cached as well.
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