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From "Daniel Wong (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (PHOENIX-4845) Support using Row Value Constructors in OFFSET clause to support paging in tables where the sort order of PK columns varies
Date Thu, 30 Aug 2018 00:56:00 GMT

     [ https://issues.apache.org/jira/browse/PHOENIX-4845?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Daniel Wong updated PHOENIX-4845:
---------------------------------
    Labels: DESC SFDC  (was: SFDC)

> Support using Row Value Constructors in OFFSET clause to support paging in tables where
the sort order of PK columns varies
> ---------------------------------------------------------------------------------------------------------------------------
>
>                 Key: PHOENIX-4845
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-4845
>             Project: Phoenix
>          Issue Type: New Feature
>            Reporter: Thomas D'Silva
>            Priority: Major
>              Labels: DESC, SFDC
>
> RVCs along with the LIMIT clause are useful for efficiently paging through rows (see
[http://phoenix.apache.org/paged.html]). 
>  However if the sorder order of the PK columns in a table varies we cannot use RVCs. 
> For eg. if the PK of a table is (A  DESC, B) we cannot use the following query to page
through the data
> {code:java}
> SELECT * FROM TABLE WHERE (A, B) < (?, ?) ORDER BY A DESC, B LIMIT 20
> {code}
> Since the rows are sorted by A desc and then by B descending we need to use the following
query
> {code:java}
> SELECT * FROM TABLE WHERE (A < ? OR (A=? AND B>?))  ORDER BY A DESC, B LIMIT 20
> {code}
> If we supported using RVCs in the offset clause we could use the offset to set the start
row of the scan. Also clients would not have to generate a complicated query.
> {code:java}
> SELECT * FROM TABLE ORDER BY A DESC, B LIMIT 20 OFFSET (?,?)
> {code}
> We would only allow using the offset if the rows are ordered by the sort order of the
PK columns.
>  
> FYI [~jfernando_sfdc]



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