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From "Runping Qi (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-3442) QuickSort may get into unbounded recursion
Date Thu, 05 Jun 2008 02:49:45 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-3442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12602522#action_12602522
] 

Runping Qi commented on HADOOP-3442:
------------------------------------


The patch looks good.

I think it is better to add randomization to the patched code.

Two possibilities:
1. instead to choose (p+r)/2, choose random(p, r) as the pivotal candidate.
2. Randomize the input data before calling quicksort (O(n)) cost.


> QuickSort may get into unbounded recursion
> ------------------------------------------
>
>                 Key: HADOOP-3442
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3442
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>    Affects Versions: 0.17.0
>            Reporter: Runping Qi
>            Assignee: Chris Douglas
>         Attachments: 3442-0.patch, 3442-0v17.patch, CheckSortBuffer.java, HADOOP-3442.patch,
overflow.zip, spillbuffers.patch
>
>


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