hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Chris Douglas (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-3442) QuickSort may get into unbounded recursion
Date Mon, 09 Jun 2008 02:21:45 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-3442?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Chris Douglas updated HADOOP-3442:
----------------------------------

    Attachment: 3442-1.patch

Proposed fix for 0.18:
* Resurrect map.sort.class property to control which sort implementation to use, add HeapSort
& BatcherSort as valid targets; keep QuickSort as the default
* Change QuickSort to recur only on the smaller partition (limits recursion depth to log\(n))
* Change QuickSort to use HeapSort once it reaches an unreasonable recursion depth (2*ceil(log\(n)))
(Introspection Sort)

Fix for 0.17.1:
* Only fix the recursion. The degenerate cases for QuickSort with median-of-three partitioning
really are uncommon.

> 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
>            Priority: Blocker
>             Fix For: 0.17.1, 0.18.0
>
>         Attachments: 3442-0.patch, 3442-0v17.patch, 3442-1.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