Mailing-List: contact dev-help@hive.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@hive.apache.org
Date: Fri, 5 Aug 2011 21:24:28 +0000 (UTC)
From: "Tim Armstrong (JIRA)" <jira@apache.org>
To: hive-dev@hadoop.apache.org
Message-ID: 
 <1625857519.13001.1312579468137.JavaMail.tomcat@hel.zones.apache.org>
In-Reply-To: 
 <588940576.10375.1312513407944.JavaMail.tomcat@hel.zones.apache.org>
Subject: [jira] [Updated] (HIVE-2350) Improve RCFile Read Speed
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


     [ https://issues.apache.org/jira/browse/HIVE-2350?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tim Armstrong updated HIVE-2350:
--------------------------------

    Status: Patch Available  (was: In Progress)

> Improve RCFile Read Speed
> -------------------------
>
>                 Key: HIVE-2350
>                 URL: https://issues.apache.org/jira/browse/HIVE-2350
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Tim Armstrong
>            Assignee: Tim Armstrong
>            Priority: Minor
>         Attachments: rcfile-2011-08-04.diff, rcfile_opt_2011-08-05.diff, rcfile_opt_2011-08-05b.diff
>
>   Original Estimate: 0h
>  Remaining Estimate: 0h
>
> By tweaking the RCFile$Reader implementation to allow more efficient memory access I was able to reduce CPU usage.  I measured the speed required to scan a gzipped RCFile, decompress and assemble into records.  CPU time was reduced by about 7% for a full table scan,  An improvement of about 2% was realised when a smaller subset of columns (3-5 out of tens) were selected.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira