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Date: Thu, 20 Jan 2011 02:14:44 -0500 (EST)
From: "ncanis (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Subject: [jira] Commented: (HBASE-3453) How about RowPaginationFilter
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    [ https://issues.apache.org/jira/browse/HBASE-3453?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12984055#action_12984055 ] 

ncanis commented on HBASE-3453:
-------------------------------


if we use ResultScanner for paging, follow code.

(I found from googling)
http://devblog.streamy.com/2009/04/23/hbase-row-key-design-for-paging-limit-offset-queries/

that will be extremely slow. (rows are 50,0000 over)

I think we should use Filter for specified position


> How about RowPaginationFilter
> -----------------------------
>
>                 Key: HBASE-3453
>                 URL: https://issues.apache.org/jira/browse/HBASE-3453
>             Project: HBase
>          Issue Type: Wish
>          Components: client
>    Affects Versions: 0.90.1
>         Environment: windows 7
>            Reporter: ncanis
>             Fix For: 0.90.0
>
>         Attachments: RowPaginationFilter.java
>
>
> I know hbase has already PageFilter.
> But, sometime we need to get row data from specified position.
> * only for newbie:
>   If you want to write custom Filter, you also add filter class to an hbase server classpath.
> {code:title=RowPaginationFilter|borderStyle=solid}
> /**
> 	 * Constructor that takes a maximum page size.
> 	 * 
> 	 * get row from offset to offset+limit ( offset<= row<=offset+limit )
> 	 * @param offset start position
> 	 * @param limit count from offset position
> 	 */
> 	public RowPaginationFilter(final int offset, final int limit) {
> 		this.offset = offset;
> 		this.limit = limit;
> 	}
> 	//true to exclude row, false to include row.
> 	@Override
> 	public boolean filterRow() {	
> 	
> 		boolean isExclude = this.rowsAccepted < this.offset || this.rowsAccepted>=this.limit+this.offset;
> 		rowsAccepted++;
> 		return isExclude;
> 	}
> {code}
> -----------------

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