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https://issues.apache.org/jira/browse/HDFS-2092?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13054247#comment-13054247
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Aaron T. Myers commented on HDFS-2092:
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Note: I'm not necessarily opposed to this change, but please justify its 
usefulness. From what I can tell so far, this patch seems to be optimizing 
something that's not actually an issue.

bq. That was just a sample of measurement for a day. 

Sure, but what was it actually measuring? Increase in child heap size per task 
attempt? Increase in heap size per TT? Something else?

bq. Also, Going forward, PIG 0.9 will store lots of meta data in the conf and 
also one can embed the PIG script itself in the conf.

I don't know much about Pig, but that sounds like a bad idea on its part. Maybe 
I'm wrong about that.

bq. This can potentially blow the TT.

Can it? I've seen users have a lot of different problems with Hadoop, but Task 
Trackers falling over because of conf objects being too large isn't one I can 
recall.

bq. Since one can store anything in the job conf, we should be careful with the 
references to this object - we should not hold for long duration.

At most these references will be held for the lifetime of a task attempt, 
right? So not so long?

> Create a light inner conf class in DFSClient
> --------------------------------------------
>
>                 Key: HDFS-2092
>                 URL: https://issues.apache.org/jira/browse/HDFS-2092
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: hdfs client
>    Affects Versions: 0.23.0
>            Reporter: Bharath Mundlapudi
>            Assignee: Bharath Mundlapudi
>             Fix For: 0.23.0
>
>         Attachments: HDFS-2092-1.patch, HDFS-2092-2.patch
>
>
> At present, DFSClient stores reference to configuration object. Since, these 
> configuration objects are pretty big at times can blot the processes which 
> has multiple DFSClient objects like in TaskTracker. This is an attempt to 
> remove the reference of conf object in DFSClient. 
> This patch creates a light inner conf class and copies the required keys from 
> the Configuration object.

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