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From "Aaron Kimball (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-6708) New file format for very large records
Date Fri, 16 Apr 2010 00:39:27 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-6708?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12857621#action_12857621
] 

Aaron Kimball commented on HADOOP-6708:
---------------------------------------

I don't think that works in this scenario. Suppose I have a record that is 8 GB long; I read
the first kilobyte or two out of the record, then intend to discard the rest and start with
the next record.

If we have a chunk size of 1 MB, then skipping through this will require 8000 seeks, or ~64000
milliseconds. Even upping this chunk size drastically to 100 MB means a 640 ms delay.


> New file format for very large records
> --------------------------------------
>
>                 Key: HADOOP-6708
>                 URL: https://issues.apache.org/jira/browse/HADOOP-6708
>             Project: Hadoop Common
>          Issue Type: New Feature
>          Components: io
>            Reporter: Aaron Kimball
>            Assignee: Aaron Kimball
>         Attachments: lobfile.pdf
>
>
> A file format that handles multi-gigabyte records efficiently, with lazy disk access

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