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https://issues.apache.org/jira/browse/HDFS-5096?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13794588#comment-13794588
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Colin Patrick McCabe commented on HDFS-5096:
--------------------------------------------

bq. Shall we remove INodeFile#cacheReplication in this patch? I believe it's 
unused now.

Good point.

bq. Also, can we please document 
dfs.namenode.path.based.cache.refresh.interval.ms in hdfs-default.xml?

added.

bq. CacheReplicationMonitor#rescanFile

I agree with Andrew's comments here... sorry for not replying earlier but I've 
been focusing on breaking out pieces into  HDFS-5358, HDFS-5348, HDFS-5349, and 
the other JIRAs.  Let me know if you think the comments in the code could be 
improved.  I still haven't replied to all of andrew's comments either... thanks 
for your patience, both of you :)

> Automatically cache new data added to a cached path
> ---------------------------------------------------
>
>                 Key: HDFS-5096
>                 URL: https://issues.apache.org/jira/browse/HDFS-5096
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: datanode, namenode
>            Reporter: Andrew Wang
>            Assignee: Colin Patrick McCabe
>         Attachments: HDFS-5096-caching.005.patch, HDFS-5096-caching.006.patch
>
>
> For some applications, it's convenient to specify a path to cache, and have 
> HDFS automatically cache new data added to the path without sending a new 
> caching request or a manual refresh command.
> One example is new data appended to a cached file. It would be nice to 
> re-cache a block at the new appended length, and cache new blocks added to 
> the file.
> Another example is a cached Hive partition directory, where a user can drop 
> new files directly into the partition. It would be nice if these new files 
> were cached.
> In both cases, this automatic caching would happen after the file is closed, 
> i.e. block replica is finalized.



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