Mailing-List: contact hadoop-dev-help@lucene.apache.org; run by ezmlm
Precedence: bulk
Reply-To: hadoop-dev@lucene.apache.org
Message-ID: <6313667.1171653305842.JavaMail.jira@brutus>
Date: Fri, 16 Feb 2007 11:15:05 -0800 (PST)
From: "Owen O'Malley (JIRA)" <jira@apache.org>
To: hadoop-dev@lucene.apache.org
Subject: [jira] Commented: (HADOOP-1017) Optimization: Reduce Overhead from
 ReflectionUtils.newInstance
In-Reply-To: <8341615.1171393805599.JavaMail.jira@brutus>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/HADOOP-1017?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12473793 ] 

Owen O'Malley commented on HADOOP-1017:
---------------------------------------

I'd vote for the synchronized map. The failure mode would just be that you look up the constructor a second time.

> Optimization: Reduce Overhead from ReflectionUtils.newInstance
> --------------------------------------------------------------
>
>                 Key: HADOOP-1017
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1017
>             Project: Hadoop
>          Issue Type: Improvement
>          Components: util
>            Reporter: Ron Bodkin
>         Attachments: cacheCtor.patch, ReflectionUtils.patch.txt, TestReflectionUtils.java
>
>
> I found that a significant amount of time on my project was being spent in creating constructors for each row of data. I dramatically optimized this performance by creating a simple WeakHashMap to cache constructors by class. For example, in a sample job I find that ReflectionUtils.newInstance takes 200 ms (2% of total) with the cache enabled, but it uses 900 ms (6% of total) without the cache.

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