hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Konstantin Shvachko (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-3442) QuickSort may get into unbounded recursion
Date Thu, 05 Jun 2008 23:06:45 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-3442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12602835#action_12602835
] 

Konstantin Shvachko commented on HADOOP-3442:
---------------------------------------------

1. QuickSort is n*logn only on average. In the worst case it is n-square. So whatever strategy
you choose there will be an input sequence (randomized or not) that will lead to the degenerate
behavior. So why QuickSort  if there are hundreds of other sorting algorithms?
2. Recursion is imperative and good for describing algorithms. In practice it should be eliminated.
Standard techniques are applicable in this case.


> 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
>
>


-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message