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Date: Mon, 8 Apr 2013 21:13:16 +0000 (UTC)
From: "Varun Sharma (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: <JIRA.12641148.1365204590209.130090.1365455596621@arcas>
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Subject: [jira] [Commented] (HBASE-8284) Allow String Offset(s) in
 ColumnPaginationFilter for bookmark based pagination
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    [ https://issues.apache.org/jira/browse/HBASE-8284?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13625817#comment-13625817 ] 

Varun Sharma commented on HBASE-8284:
-------------------------------------

Okay, I uploaded v2 with your comments incorporated.

For the if{} else{} block, I just left it as it is, since I specifically want to bring out that we use columnOffset if available (thats an override) otherwise, we always resort to ColumnPaginationFilter.
                
> Allow String Offset(s) in ColumnPaginationFilter for bookmark based pagination
> ------------------------------------------------------------------------------
>
>                 Key: HBASE-8284
>                 URL: https://issues.apache.org/jira/browse/HBASE-8284
>             Project: HBase
>          Issue Type: Improvement
>          Components: Filters
>    Affects Versions: 0.94.6.1
>            Reporter: Varun Sharma
>            Assignee: Varun Sharma
>            Priority: Minor
>             Fix For: 0.98.0, 0.94.8, 0.95.1
>
>         Attachments: 8284-0.94.txt, 8284-0.94-v2.txt
>
>
> Attaching from email to HBase user mailing list:
> I am thinking of adding a string offset to ColumnPaginationFilter. There are two reasons:
> 1) For deep pagination, you can seek using SEEK_NEXT_USING_HINT.
> 2) For correctness reasons, this approach is better if the list of columns is mutation. Lets say you get 1st 50 columns using the current approach. In the mean time some columns are inserted amongst the 1st 50 columns. Now you request the 2nd set of 50 columns. Chances are that you will have duplicates amongst the 2 sets (1st 50 and 2nd 50). If instead you used the last column of the 1st 50 as a string offset for getting the 2nd set of columns, the chances of getting dups is significantly lower.
> This becomes important for user facing interactive applications. Particularly where consistency etc. are not as important since those are best effort services. But showing duplicates across pages is pretty bad.
> Please let me know if this makes sense and is feasible. Basically, I would like a string offset passed to ColumnPaginationFilter as an alternative constructor. If the string offset is supplied, then, I would like to seek to either the column supplied or if the column is deleted, seek to the column just greater than the supplied column.

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