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From "Maryann Xue (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (PHOENIX-2167) Add new interface in QueryPlan for pushing down a limit value.
Date Fri, 06 Nov 2015 02:02:27 GMT

     [ https://issues.apache.org/jira/browse/PHOENIX-2167?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Maryann Xue updated PHOENIX-2167:
---------------------------------
    Labels: calcite  (was: )

> Add new interface in QueryPlan for pushing down a limit value.
> --------------------------------------------------------------
>
>                 Key: PHOENIX-2167
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2167
>             Project: Phoenix
>          Issue Type: Sub-task
>            Reporter: Maryann Xue
>            Assignee: Maryann Xue
>              Labels: calcite
>         Attachments: PHOENIX-2167.patch
>
>   Original Estimate: 48h
>  Remaining Estimate: 48h
>
> Calcite rel trees are compiled bottom-up into Phoenix QueryPlans, the easiest way to
implement a Limit RelNode in the tree is to create a ClientScanPlan with the limit value and
wrap it around the inner plan. However, oftentimes this may not be efficient.
> For example, select * from T limit 10, the original Phoenix compiler would generate a
ScanPlan with limit 10, apply a PageFilter and avoid using sophisticated or expensive ResultIterators.
> So it would make sense to push down the limit to a QueryPlan as low as possible and create
a new copy of the plan based on this rule.



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