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From "Pete Wyckoff (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-4065) support for reading binary data from flat files
Date Tue, 09 Sep 2008 05:45:45 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-4065?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12629398#action_12629398
] 

Pete Wyckoff commented on HADOOP-4065:
--------------------------------------

It looks like we posted complimentary patches :) I think we should keep my RecordReader, but
use your implementation of the TypedFileTransport as it's more general since it uses the serialization
framework.

This would address the use case of files whose serializers are set in the config file and
self describing files like sequence files and TRecordStream and I would guess, TFile but I
haven't looked at it.

-- pete


> support for reading binary data from flat files
> -----------------------------------------------
>
>                 Key: HADOOP-4065
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4065
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>            Reporter: Joydeep Sen Sarma
>         Attachments: HADOOP-4065.0.txt, ThriftFlatFile.java
>
>
> like textinputformat - looking for a concrete implementation to read binary records from
a flat file (that may be compressed).
> it's assumed that hadoop can't split such a file. so the inputformat can set splittable
to false.
> tricky aspects are:
> - how to know what class the file contains (has to be in a configuration somewhere).
> - how to determine EOF (would be nice if hadoop can determine EOF and not have the deserializer
throw an exception  (which is hard to distinguish from a exception due to corruptions?)).
this is easy for non-compressed streams - for compressed streams - DecompressorStream has
a useful looking getAvailable() call - except the class is marked package private.

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