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https://issues.apache.org/jira/browse/MAPREDUCE-4907?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13549256#comment-13549256
]
Hudson commented on MAPREDUCE-4907:
-----------------------------------
Integrated in Hadoop-trunk-Commit #3210 (See
[https://builds.apache.org/job/Hadoop-trunk-Commit/3210/])
MAPREDUCE-4907. TrackerDistributedCacheManager issues too many
getFileStatus calls. (sandyr via tucu) (Revision 1431166)
Result = SUCCESS
tucu : http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1431166
Files :
* /hadoop/common/trunk/hadoop-mapreduce-project/CHANGES.txt
*
/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/JobSubmitter.java
*
/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/filecache/ClientDistributedCacheManager.java
> 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
> Fix For: 1.2.0, 2.0.3-alpha
>
> 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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