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Posted to dev@drill.apache.org by "Gautam Kumar Parai (JIRA)" <ji...@apache.org> on 2018/01/16 23:05:00 UTC

[jira] [Created] (DRILL-6093) Unneeded columns in Drill logical project

Gautam Kumar Parai created DRILL-6093:
-----------------------------------------

             Summary: Unneeded columns in Drill logical project
                 Key: DRILL-6093
                 URL: https://issues.apache.org/jira/browse/DRILL-6093
             Project: Apache Drill
          Issue Type: Bug
    Affects Versions: 1.12.0, 1.11.0
            Reporter: Gautam Kumar Parai
            Assignee: Gautam Kumar Parai
             Fix For: 1.12.0


Here is an example query with the corresponding logical plan. The project contains unnecessary columns L_ORDERKEY, O_ORDERKEY in the projection even when it is not required by subsequent operators e.g. DrillJoinRel.

EXPLAIN PLAN without implementation FOR SELECT L.L_QUANTITY FROM cp.`tpch/lineitem.parquet` L, cp.`tpch/orders.parquet` O WHERE cast(L.L_ORDERKEY as int) = cast(O.O_ORDERKEY as int);

*+------+------+*

*|* *text* *|* *json* *|*

*+------+------+*

*|* DrillScreenRel

  DrillProjectRel(L_QUANTITY=[$1])

    DrillJoinRel(condition=[=($2, $4)], joinType=[inner])

      DrillProjectRel(L_ORDERKEY=[$0], L_QUANTITY=[$1], $f2=[CAST($0):INTEGER])

        DrillScanRel(table=[[cp, tpch/lineitem.parquet]], groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=classpath:/tpch/lineitem.parquet]], selectionRoot=classpath:/tpch/lineitem.parquet, numFiles=1, numRowGroups=1, usedMetadataFile=false, columns=[`L_ORDERKEY`, `L_QUANTITY`]]])

      DrillProjectRel(O_ORDERKEY=[$0], $f1=[CAST($0):INTEGER])

        DrillScanRel(table=[[cp, tpch/orders.parquet]], groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=classpath:/tpch/orders.parquet]], selectionRoot=classpath:/tpch/orders.parquet, numFiles=1, numRowGroups=1, usedMetadataFile=false, columns=[`O_ORDERKEY`]]])



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