[jira] Updated: (HADOOP-4065) support for reading binary data from flat files

["Pete Wyckoff (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HADOOP-4065?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Pete Wyckoff updated HADOOP-4065:
---------------------------------

    Attachment: HADOOP-4065.0.txt

This is what the proposal would look like. It:

1. adds the TypedSplittableFile interface
2. changes SequenceFile.Reader to implement TypedSplittableFile and adds an initialize method and an empty constructor
3. implements TypedSplittableFileRecordReader - just copied the code from SequenceFileRecordReader and changed the constructor only
4. change SequenceFileRecordReader to extend TypedSplittableFileRecordReader and have its constructor just construct the parent class.

Still a work in progress, but this kind of shows the API and the changes to SequenceFileRecordReader.



> 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
>
>
> 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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