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https://issues.apache.org/jira/browse/HADOOP-4065?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12632067#action_12632067
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Pete Wyckoff commented on HADOOP-4065:
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bq. In either case, changes to the serialization framework seems like serious
overkill.
you are right - I don't know why I went that direction. It should be exactly
the oppostite of the way I coded it up.
All one needs is some way of getting SerializationContext information (to
instantiate the right Serialization Object and then the actual subclass we want
to deserialize; e.g., Record/MyRecordObj). [this was called RowSource in joy's
code example]
And then a simple record reader that uses that info to instantiate a
deserializer and done.
No changes to the serialization framework.
I actually have that with unit tests and just need to clean up the
documentation and such.
-- 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, HADOOP-4065.1.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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