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From "Jinfeng Ni (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (DRILL-3716) Drill should push filter past aggregate in order to improve query performance.
Date Thu, 27 Aug 2015 17:47:46 GMT

     [ https://issues.apache.org/jira/browse/DRILL-3716?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jinfeng Ni resolved DRILL-3716.
-------------------------------
    Resolution: Fixed

> Drill should push filter past aggregate in order to improve query performance.
> ------------------------------------------------------------------------------
>
>                 Key: DRILL-3716
>                 URL: https://issues.apache.org/jira/browse/DRILL-3716
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Query Planning & Optimization
>            Reporter: Jinfeng Ni
>            Assignee: Jinfeng Ni
>             Fix For: 1.2.0
>
>
> For the following query which has a filter on top of an aggregation, Drill's currently
push the filter pass through the aggregation. As a result, we may miss some optimization opportunity.
For instance, such filter could potentially been pushed into scan if it qualifies for partition
pruning.
> For the following query:
> {code}
> select n_regionkey, cnt from 
>      (select n_regionkey, count(*) cnt 
>       from (select n.n_nationkey, n.n_regionkey, n.n_name 
>                from cp.`tpch/nation.parquet` n 
>                   left join 
>                        cp.`tpch/region.parquet` r 
>                 on n.n_regionkey = r.r_regionkey) 
>        group by n_regionkey) 
> where n_regionkey = 2;
> {code}
> The current plan shows a filter (00-04) on top of aggregation(00-05). The better plan
would have the filter pushed pass the aggregation. 
> The root cause of this problem is Drill's ruleset does not include  FilterAggregateTransoposeRule
from Calcite library.
> {code}
> 00-01      Project(n_regionkey=[$0], cnt=[$1])
> 00-02        Project(n_regionkey=[$0], cnt=[$1])
> 00-03          SelectionVectorRemover
> 00-04            Filter(condition=[=($0, 2)])
> 00-05              StreamAgg(group=[{0}], cnt=[COUNT()])
> 00-06                Project(n_regionkey=[$0])
> 00-07                  MergeJoin(condition=[=($0, $1)], joinType=[left])
> 00-09                    SelectionVectorRemover
> 00-11                      Sort(sort0=[$0], dir0=[ASC])
> 00-13                        Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath
[path=classpath:/tpch/nation.parquet]], selectionRoot=classpath:/tpch/nation.parquet, numFiles=1,
columns=[`n_regionkey`]]])
> 00-08                    SelectionVectorRemover
> 00-10                      Sort(sort0=[$0], dir0=[ASC])
> 00-12                        Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath
[path=classpath:/tpch/region.parquet]], selectionRoot=classpath:/tpch/region.parquet, numFiles=1,
columns=[`r_regionkey`]]])
> {code}



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