Jinfeng Ni created DRILL-636:
--------------------------------
Summary: 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
Reporter: Jinfeng Ni
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.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
