Mailing-List: contact common-issues-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: common-issues@hadoop.apache.org
Message-ID: <1404050.9641280182457017.JavaMail.jira@thor>
Date: Mon, 26 Jul 2010 18:14:17 -0400 (EDT)
From: "Doug Cutting (JIRA)" <jira@apache.org>
To: common-issues@hadoop.apache.org
Subject: [jira] Updated: (HADOOP-6881) The efficient comparators aren't
 always used except for BytesWritable and Text
In-Reply-To: <28363686.3111280170396575.JavaMail.jira@thor>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


     [ https://issues.apache.org/jira/browse/HADOOP-6881?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Doug Cutting updated HADOOP-6881:
---------------------------------

    Status: Open  (was: Patch Available)

> The efficient comparators aren't always used except for BytesWritable and Text
> ------------------------------------------------------------------------------
>
>                 Key: HADOOP-6881
>                 URL: https://issues.apache.org/jira/browse/HADOOP-6881
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 0.20.0
>            Reporter: Owen O'Malley
>            Assignee: Owen O'Malley
>             Fix For: 0.20.3
>
>         Attachments: h-6881.patch, HADOOP-6881.patch, HADOOP-6881.patch
>
>
> When we moved from Java 4 to Java 5 (and then 6), there was a change in the JVM semantics such that references to a class such as IntWritable.class no longer forces initialization. Since all of the Writables depend on their class static blocks to register their fast comparators, that can happen *after* we look up the comparator. In that case, the framework will fall back to the generic comparator that deserializes both keys and does the object compare, which may cause a huge slow down in the sort.

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