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Date: Thu, 20 Oct 2011 01:48:10 +0000 (UTC)
From: "Jonathan Gray (Commented) (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
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Subject: [jira] [Commented] (HBASE-1183) New MR splitting algorithm and
 other new features need a way to split a key range in N chunks
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    [ https://issues.apache.org/jira/browse/HBASE-1183?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13131261#comment-13131261 ] 

Jonathan Gray commented on HBASE-1183:
--------------------------------------

Wow, really got me thinking back.  I honestly don't remember exactly why.

We convert them to BigInteger so we can do:  (stop - start) / numsplits = interval

Something related to signed/unsigned?  Reading the code it does seem okay.  Good thing I didn't write a unit test.

Are you seeing that it's broken in some way?  I can spend a little more time looking at it if necessary.
                
> New MR splitting algorithm and other new features need a way to split a key range in N chunks
> ---------------------------------------------------------------------------------------------
>
>                 Key: HBASE-1183
>                 URL: https://issues.apache.org/jira/browse/HBASE-1183
>             Project: HBase
>          Issue Type: Improvement
>          Components: util
>            Reporter: Jonathan Gray
>            Assignee: Jonathan Gray
>            Priority: Minor
>             Fix For: 0.20.0
>
>         Attachments: hbase-1183-v1.patch, hbase-1183-v2.patch, hbase-1183-v3.patch, hbase-1183-v4.patch
>
>
> For HBASE-1172 and other functionality coming soon, we need to be able to take a [start,stop) range and divide it into chunks.
> For example, we have 10 regions but want to run 30 maps.  We need to divide each region into three key ranges for the start/stop of each scanner.
> Implementing using java.math.BigInteger
> Will also include a couple additional helpers in Bytes to make life easy.

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