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https://issues.apache.org/jira/browse/HDFS-5563?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13834311#comment-13834311
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Jing Zhao commented on HDFS-5563:
---------------------------------

bq. In the future, we can consider use fix-sized cache blocks so that it's easy 
to find the cached data for read.

Sounds good. +1 pending Jenkins.

> NFS gateway should commit the buffered data when read request comes after 
> write to the same file
> ------------------------------------------------------------------------------------------------
>
>                 Key: HDFS-5563
>                 URL: https://issues.apache.org/jira/browse/HDFS-5563
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: nfs
>            Reporter: Brandon Li
>            Assignee: Brandon Li
>         Attachments: HDFS-5563.001.patch, HDFS-5563.002.patch, 
> HDFS-5563.003.patch
>
>
> HDFS write is asynchronous and data may not be available to read immediately 
> after write.
> One of the main reason is that DFSClient doesn't flush data to DN until its 
> local buffer is full.
> To workaround this problem, when a read comes after write to the same file, 
> NFS gateway should sync the data so the read request can get the latest 
> content. The drawback is that, the frequent hsync() call can slow down data 
> write.



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