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From "Chris Douglas (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-3019) want input sampler & sorted partitioner
Date Mon, 15 Sep 2008 22:39:44 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-3019?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Chris Douglas updated HADOOP-3019:
----------------------------------

    Attachment: 3019-0.patch

Adapted TotalOrderPartitioner and input sampler from HADOOP-3402, with the following changes:
* Adds two other kinds of samplers
* Made memcmp-able types (Text, BytesWritable) use the trie, other data structures do a binary
search over the partition keyset
* Adds a unit test for the partitioner

> want input sampler & sorted partitioner
> ---------------------------------------
>
>                 Key: HADOOP-3019
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3019
>             Project: Hadoop Core
>          Issue Type: New Feature
>          Components: mapred
>            Reporter: Doug Cutting
>         Attachments: 3019-0.patch
>
>
> The input sampler should generate a small, random sample of the input, saved to a file.
> The partitioner should read the sample file and partition keys into relatively even-sized
key-ranges, where the partition numbers correspond to key order.
> Note that when the sampler is used for partitioning, the number of samples required is
proportional to the number of reduce partitions.  10x the intended reducer count should give
good results.

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