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Date: Tue, 8 Dec 2009 18:17:18 +0000 (UTC)
From: "Owen O'Malley (JIRA)" <jira@apache.org>
To: mapreduce-issues@hadoop.apache.org
Subject: [jira] Commented: (MAPREDUCE-606) Implement a binary input/output
 format for Streaming
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    [ https://issues.apache.org/jira/browse/MAPREDUCE-606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12787620#action_12787620 ] 

Owen O'Malley commented on MAPREDUCE-606:
-----------------------------------------

I'd propose that we implement this in terms of the org.apache.hadoop.streaming.io.InputWriter and OutputReader. A reader/writer that left the bytes alone, but that quoted the other characters would be great:

{noformat}
newline -> \n
return -> \r
backslash -> \\
tab -> \t
{noformat}

Then it would be easy to get quoted binary into streaming applications.

> Implement a binary input/output format for Streaming
> ----------------------------------------------------
>
>                 Key: MAPREDUCE-606
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-606
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: contrib/streaming
>            Reporter: Arun C Murthy
>         Attachments: hadoop-3227.patch
>
>
> Lots of streaming applications process textual data with 1 record per line and fields separated by a delimiter. It turns out that there is no point in using any of Hadoop's input/output formats since the streaming script/binary itself will parse the input and break into records and fields. In such cases we should provide users with a binary input/output format which just sends 64k (or so) blocks of data directly from HDFS to the streaming application.
> I did something very similar for Pig-Streaming (PIG-94 - BinaryStorage) which resulted in 300%+ speedup for scanning (identity mapper & map-only jobs) data... the parsing done by input/output formats in these cases were pure-overhead.

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