Mailing-List: contact issues-help@hbase.apache.org; run by ezmlm
Precedence: bulk
Date: Wed, 12 Sep 2012 01:47:07 +1100 (NCT)
From: "Lars Hofhansl (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: <595469443.63660.1347374827877.JavaMail.jiratomcat@arcas>
In-Reply-To: <296849296.63654.1347374589531.JavaMail.jiratomcat@arcas>
Subject: [jira] [Commented] (HBASE-6757) Very inefficient behaviour of scan
 using FilterList
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/HBASE-6757?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13453068#comment-13453068 ] 

Lars Hofhansl commented on HBASE-6757:
--------------------------------------

Interesting. I just looked at the code and I agree this is wrong.
                
> Very inefficient behaviour of scan using FilterList
> ---------------------------------------------------
>
>                 Key: HBASE-6757
>                 URL: https://issues.apache.org/jira/browse/HBASE-6757
>             Project: HBase
>          Issue Type: Improvement
>          Components: filters
>    Affects Versions: 0.90.6
>            Reporter: Jerry Lam
>
> The behaviour of scan is very inefficient when using with FilterList.
> The FilterList rewrites the return code from NEXT_ROW to SKIP from a filter if Operator.MUST_PASS_ALL is used. 
> This happens when using ColumnPrefixFilter. Even though the ColumnPrefixFilter indicates to jump to NEXT_ROW because no further match can be found, the scan continues to scan all versions of a column in that row and all columns of that row because the ReturnCode from ColumnPrefixFilter has been rewritten by the FilterList from NEXT_ROW to SKIP. 
> This is particularly inefficient when there are many versions in a column because the check is performed on all versions of the column instead of just by checking the qualifier of the column name.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira