[
https://issues.apache.org/jira/browse/DRILL-6896?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Aman Sinha updated DRILL-6896:
------------------------------
Description:
[~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:
-------------
{noformat}
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`]]])
{noformat}
On 1.14.0:
-------------
{noformat}
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`]]])
{noformat}
was:
[~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`]]])
> 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:
> -------------
> {noformat}
> 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`]]])
> {noformat}
> On 1.14.0:
> -------------
> {noformat}
> 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`]]])
> {noformat}
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