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https://issues.apache.org/jira/browse/DRILL-636?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Aman Sinha updated DRILL-636:
-----------------------------
Fix Version/s: (was: Future)
1.0.0
> Push Limit operator past project, left outer join, union all operator and
> down into scan operator
> --------------------------------------------------------------------------------------------------
>
> Key: DRILL-636
> URL: https://issues.apache.org/jira/browse/DRILL-636
> Project: Apache Drill
> Issue Type: Improvement
> Components: Query Planning & Optimization
> Reporter: Jinfeng Ni
> Assignee: Aman Sinha
> Fix For: 1.0.0
>
>
> When we have a limit operator on top of project, left outer join, union all
> operator, we should push the limit operator, until the limit is put into scan
> operator. Doing so, it will reduce the amount of data scanned by the scan
> operator.
> For instance,
> Select COL1, COL2 FROM T1 LIMIT 5;
> LIMIT (5)
> \
> PROJECT (COL1, COL2)
> \
> SCAN (T1).
> We need push limit past project, down into scan.
> Similar applies to left outer join, or union all.
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