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https://issues.apache.org/jira/browse/HDFS-6871?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14103743#comment-14103743
 ] 

Hadoop QA commented on HDFS-6871:
---------------------------------

{color:green}+1 overall{color}.  Here are the results of testing the latest 
attachment 
  http://issues.apache.org/jira/secure/attachment/12663073/HDFS-6871.003.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}.  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 2.0.3) 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-hdfs-project/hadoop-hdfs.

    {color:green}+1 contrib tests{color}.  The patch passed contrib unit tests.

Test results: 
https://builds.apache.org/job/PreCommit-HDFS-Build/7690//testReport/
Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/7690//console

This message is automatically generated.

> Improve NameNode performance when creating file  
> -------------------------------------------------
>
>                 Key: HDFS-6871
>                 URL: https://issues.apache.org/jira/browse/HDFS-6871
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: namenode, performance
>            Reporter: Yi Liu
>            Assignee: Yi Liu
>            Priority: Critical
>             Fix For: 2.6.0
>
>         Attachments: HDFS-6871.001.patch, HDFS-6871.002.patch, 
> HDFS-6871.003.patch
>
>
> Creating file with overwrite flag will cause NN fall into flush edit logs and 
> block other requests if the file exists.
> When we create a file with overwrite flag (default is true) in HDFS, NN will 
> remove original file if it exists. In FSNamesystem#startFileInternal, NN 
> already holds the write lock, it calls {{deleteInt}} if the file exists, 
> there is logSync in {{deleteInt}}. So in this case, logSync is under write 
> lock, it will heavily affect the NN performance. 
> We should ignore the force logSync in {{deleteInt}} in this case.



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