[jira] [Commented] (PHOENIX-172) Support the ability for a client to do query more

["Thomas D'Silva (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PHOENIX-172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16648604#comment-16648604 ] 

Thomas D'Silva commented on PHOENIX-172:
----------------------------------------

[~lhofhansl] I was looking through this JIRA and saw that you came up with the original suggestion to support paging through data using row value constructors.  I don't think this works if the pk columns are in mixed sort order. For example if we have a 
table with  A desc, B asc with the following data:

{code}
A (desc), B (asc)
c , 1
b , 1
b , 2
b , 3
a , 2
{code}

If the last row that was read was ('b',2) and we query with RVC WHERE (A, B) < ('b',2) the following rows would be returned
{code}
('b',1) 
('a',2) 
{code}
We wouldn't want ('b',1)  to be returned. I think we can only use RVCs to page through data if the sort order of the pk columns is the same, WDYT?

> Support the ability for a client to do query more
> -------------------------------------------------
>
>                 Key: PHOENIX-172
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-172
>             Project: Phoenix
>          Issue Type: Task
>    Affects Versions: 2.1.0
>            Reporter: James Taylor
>            Assignee: Samarth Jain
>              Labels: enhancement
>
> Clients often need the ability to "page" through query results that have more row results than are displayable on a single screen. SQL provides LIMIT and OFFSET which is often used for this purpose, however supporting OFFSET in a performant manner is not possible with HBase. Instead, an alternate way of supporting query-more functionality (suggested by @larsh) is through  [row values constructors](http://publib.boulder.ibm.com/infocenter/soliddb/v6r3/index.jsp?topic=/com.ibm.swg.im.soliddb.sql.doc/doc/row.value.constructors.html)  which has been in the SQL spec since SQL-92. It has PostGres support as well with the benefits explained well [here](https://wiki.postgresql.org/images/3/35/Pagination_Done_the_PostgreSQL_Way.pdf) .



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