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From "Todd Lipcon (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-3205) Read multiple chunks directly from FSInputChecker subclass into user buffers
Date Thu, 05 Nov 2009 00:11:32 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-3205?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Todd Lipcon updated HADOOP-3205:
--------------------------------

    Description: 
Implementations of FSInputChecker and FSOutputSummer like DFS do not have access to full user
buffer. At any time DFS can access only up to 512 bytes even though user usually reads with
a much larger buffer (often controlled by io.file.buffer.size). This requires implementations
to double buffer data if an implementation wants to read or write larger chunks of data from
underlying storage.

We could separate changes for FSInputChecker and FSOutputSummer into two separate jiras.



  was:

Implementations of FSInputChecker and FSOutputSummer like DFS do not have access to full user
buffer. At any time DFS can access only up to 512 bytes even though user usually reads with
a much larger buffer (often controlled by io.file.buffer.size). This requires implementations
to double buffer data if an implementation wants to read or write larger chunks of data from
underlying storage.

We could separate changes for FSInputChecker and FSOutputSummer into two separate jiras.



       Assignee: Todd Lipcon  (was: Raghu Angadi)
        Summary: Read multiple chunks directly from FSInputChecker subclass into user buffers
 (was: FSInputChecker and FSOutputSummer should allow better access to user buffer)

Renaming ticket to focus on FSInputChecker. Let's do this one step at a time and open another
JIRA for OutputSummer

> Read multiple chunks directly from FSInputChecker subclass into user buffers
> ----------------------------------------------------------------------------
>
>                 Key: HADOOP-3205
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3205
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: fs
>            Reporter: Raghu Angadi
>            Assignee: Todd Lipcon
>         Attachments: hadoop-3205.txt
>
>
> Implementations of FSInputChecker and FSOutputSummer like DFS do not have access to full
user buffer. At any time DFS can access only up to 512 bytes even though user usually reads
with a much larger buffer (often controlled by io.file.buffer.size). This requires implementations
to double buffer data if an implementation wants to read or write larger chunks of data from
underlying storage.
> We could separate changes for FSInputChecker and FSOutputSummer into two separate jiras.

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