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Posted to mapreduce-issues@hadoop.apache.org by "Antonio Piccolboni (JIRA)" <ji...@apache.org> on 2012/07/23 22:13:34 UTC
[jira] [Commented] (MAPREDUCE-606) Implement a binary input/output
format for Streaming
[ https://issues.apache.org/jira/browse/MAPREDUCE-606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13420931#comment-13420931 ]
Antonio Piccolboni commented on MAPREDUCE-606:
----------------------------------------------
This seems equivalent to HADOOP-1722, raw format. Eric opposed quoting back then for reasons unclear to me, but eventually the choice was <rec length><raw bytes>. I may be be missing the fine points here, but this seem to me a revival of the quoting idea rejected back then.
> 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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