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https://issues.apache.org/jira/browse/HDFS-6871?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yi Liu updated HDFS-6871:
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    Attachment: HDFS-6871.001.patch

The patch adds an option of whether to do logSync for {{deleteInt}}.

> 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
>
>
> 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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