Mailing-List: contact issues-help@hbase.apache.org; run by ezmlm
Precedence: bulk
Date: Fri, 10 Jun 2011 19:22:58 +0000 (UTC)
From: "stack (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: 
 <220508209.11666.1307733778880.JavaMail.tomcat@hel.zones.apache.org>
In-Reply-To: 
 <1324594057.23772.1304576103124.JavaMail.tomcat@hel.zones.apache.org>
Subject: [jira] [Commented] (HBASE-3855) Performance degradation of memstore
 because reseek is linear
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/HBASE-3855?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13047383#comment-13047383 ] 

stack commented on HBASE-3855:
------------------------------

Committed to branch and Andrew's suggestion.

> Performance degradation of memstore because reseek is linear
> ------------------------------------------------------------
>
>                 Key: HBASE-3855
>                 URL: https://issues.apache.org/jira/browse/HBASE-3855
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: dhruba borthakur
>            Assignee: dhruba borthakur
>            Priority: Blocker
>             Fix For: 0.92.0
>
>         Attachments: memstoreReseek.txt, memstoreReseek2.txt
>
>
> The scanner use reseek to find the next row (or next column) as part of a scan. The reseek code iterates over a Set to position itself at the right place. If there are many thousands of kvs that need to be skipped over, then the time-cost is very high. In this case, a seek would be far lesser in cost than a reseek.

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