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https://issues.apache.org/jira/browse/DRILL-3383?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14603024#comment-14603024
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Jinfeng Ni commented on DRILL-3383:
-----------------------------------
The additional project, although not optimal, would not lead to non-trial
performance overhead. For the redundant project operator, when it does not have
any evaluation ( which is the case in the plan you got, since the projected
expression is same as the input), Drill's execution only need to transfer the
buffer from incoming batch to the outgoing batch, which would not cause big
performance overhead.
Given that, I change from "Major" to "Minor".
> CTAS Auto Partitioning : We are adding an additional project to the plan
> ------------------------------------------------------------------------
>
> Key: DRILL-3383
> URL: https://issues.apache.org/jira/browse/DRILL-3383
> Project: Apache Drill
> Issue Type: Bug
> Components: Query Planning & Optimization
> Reporter: Rahul Challapalli
> Assignee: Jinfeng Ni
> Priority: Minor
> Fix For: 1.1.0
>
>
> git.commit.id.abbrev=5a34d81
> I used the below query to create a paritioned data set
> {code}
> create table `lineitem` partition by (l_moddate) as select l.*, l_shipdate -
> extract(day from l_shipdate) + 1 l_moddate from cp.`tpch/lineitem.parquet` l;
> {code}
> The plan for the below query has 2 projects instead of 1
> {code}
> explain plan for select * from `lineitem` where l_moddate = date '1994-07-01';
> 00-00 Screen
> 00-01 Project(*=[$0])
> 00-02 Project(*=[$0])
> 00-03 Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath
> [path=/drill/testdata/ctas_auto_partition/tpch_single_partition/lineitem/0_0_31.parquet]],
>
> selectionRoot=/drill/testdata/ctas_auto_partition/tpch_single_partition/lineitem,
> numFiles=1, columns=[`*`]]])
> {code}
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