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https://issues.apache.org/jira/browse/DRILL-6896?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Aman Sinha updated DRILL-6896:
------------------------------
Summary: Extraneous columns being projected past a join (was: Extraneous
columns being projected in Drill 1.15)
> Extraneous columns being projected past a join
> ----------------------------------------------
>
> Key: DRILL-6896
> URL: https://issues.apache.org/jira/browse/DRILL-6896
> Project: Apache Drill
> Issue Type: Improvement
> Affects Versions: 1.15.0
> Reporter: Karthikeyan Manivannan
> Assignee: Aman Sinha
> Priority: Major
>
> [~rhou] noted that TPCH13 on Drill 1.15 was running slower than Drill 1.14.
> Analysis revealed that an extra column was being projected in 1.15 and the
> slowdown was because the extra column was being unnecessarily pushed across
> an exchange.
> Here is a simplified query written by [~amansinha100] that exhibits the same
> problem :
> In first plan, o_custkey and o_comment are both extraneous projections.
> In the second plan (on 1.14.0), also, there is an extraneous projection:
> o_custkey but not o_comment.
> On 1.15.0:
> -------------
> explain plan without implementation for
> select
> c.c_custkey
> from
> cp.`tpch/customer.parquet` c
> left outer join cp.`tpch/orders.parquet` o
> on c.c_custkey = o.o_custkey
> and o.o_comment not like '%special%requests%'
> ;
> DrillScreenRel
> DrillProjectRel(c_custkey=[$0])
> DrillProjectRel(c_custkey=[$2], o_custkey=[$0], o_comment=[$1])
> DrillJoinRel(condition=[=($2, $0)], joinType=[right])
> DrillFilterRel(condition=[NOT(LIKE($1, '%special%requests%'))])
> 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_custkey`, `o_comment`]]])
> DrillScanRel(table=[[cp, tpch/customer.parquet]], groupscan=[ParquetGroupScan
> [entries=[ReadEntryWithPath [path=classpath:/tpch/customer.parquet]],
> selectionRoot=classpath:/tpch/customer.parquet, numFiles=1, numRowGroups=1,
> usedMetadataFile=false, columns=[`c_custkey`]]])
> On 1.14.0:
> -----------------
> DrillScreenRel
> DrillProjectRel(c_custkey=[$0])
> DrillProjectRel(c_custkey=[$1], o_custkey=[$0])
> DrillJoinRel(condition=[=($1, $0)], joinType=[right])
> DrillProjectRel(o_custkey=[$0])
> DrillFilterRel(condition=[NOT(LIKE($1, '%special%requests%'))])
> 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_custkey`, `o_comment`]]])
> DrillScanRel(table=[[cp, tpch/customer.parquet]], groupscan=[ParquetGroupScan
> [entries=[ReadEntryWithPath [path=classpath:/tpch/customer.parquet]],
> selectionRoot=classpath:/tpch/customer.parquet, numFiles=1, numRowGroups=1,
> usedMetadataFile=false, columns=[`c_custkey`]]])
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