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From "Varun Sharma (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-8284) Allow String Offset(s) in ColumnPaginationFilter for bookmark based pagination
Date Fri, 05 Apr 2013 23:31:15 GMT
Varun Sharma created HBASE-8284:

             Summary: Allow String Offset(s) in ColumnPaginationFilter for bookmark based
                 Key: HBASE-8284
                 URL: https://issues.apache.org/jira/browse/HBASE-8284
             Project: HBase
          Issue Type: Improvement
          Components: Filters
    Affects Versions:
            Reporter: Varun Sharma
            Priority: Minor
             Fix For: 0.94.7

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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