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https://issues.apache.org/jira/browse/HBASE-605?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12599181#action_12599181
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Clint Morgan commented on HBASE-605:
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Unfortunately I need the NavigableSet to get a descending iterator. SortedSet 
does not provide this functionality. Could use some 3rd party data structure 
but, ...

I don't get the IOException compile error, thats a java6 change too...

For the time being, I'm inclined to just leave this as a java6 patch and wait 
until java6 adoption to apply it. Works for me now, and I need to spend time on 
other things.


> allow scanners which return results ordred by a column value
> ------------------------------------------------------------
>
>                 Key: HBASE-605
>                 URL: https://issues.apache.org/jira/browse/HBASE-605
>             Project: Hadoop HBase
>          Issue Type: New Feature
>          Components: client, regionserver
>    Affects Versions: 0.2.0
>            Reporter: Clint Morgan
>            Priority: Minor
>         Attachments: hbase-605-v2.patch, hbase-605-v3.patch, hbase-605.patch
>
>
> We would like to be able to scan though tables with results ordered by 
> (deserialized) column values. This approach maintains an in-memory sorted set 
> for each ordered-by column in each HStore. This allows us to iterate through 
> the keys in column order, and to random reads on the key to get the full row.
> Without the index, then we have to scan through all the rows to get the first 
> result ordered by a column. Thus, when R is the number of rows in a table,  N 
> is the number of ordered-by rows we want, and R >> N we can save a lot of 
> work by not doing the full table scan.

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