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https://issues.apache.org/jira/browse/DRILL-5691?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16102998#comment-16102998
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weijie.tong edited comment on DRILL-5691 at 7/27/17 9:46 AM:
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sync message, I have solved this issue.
As [~amansinha100] and [~julianhyde] mentioned at the email, now Drill treats
cartesian join only when one of its sub inputs is a scalar. The problem here is
that now, only aggregates without group by are considered scalar. My case shows
that a table scan with only one row should also be considered as a scalar.
I will give a commit to enhance this. By the way ,thanks Aman and Julian for
your patient advice.
was (Author: weijie):
sync message, I have solved this issue.
As [~amansinha100] and [~julianhyde] mentioned at the email, now Drill treats
cartesian join only when one of its sub input is a scalar. The problem here is
that only aggregates without group by are considered scalar. My case shows that
a table with only one row should also be considered a scalar.
I will give a commit to enhance this. By the way ,thanks Aman and Julian for
your patient advice.
> multiple count distinct query planning error at physical phase
> ---------------------------------------------------------------
>
> Key: DRILL-5691
> URL: https://issues.apache.org/jira/browse/DRILL-5691
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Relational Operators
> Affects Versions: 1.9.0, 1.10.0
> Reporter: weijie.tong
>
> I materialized the count distinct query result in a cache , added a plugin
> rule to translate the (Aggregate、Aggregate、Project、Scan) or
> (Aggregate、Aggregate、Scan) to (Project、Scan) at the PARTITION_PRUNING phase.
> Then ,once user issue count distinct queries , it will be translated to query
> the cache to get the result.
> eg1: " select count(*),sum(a) ,count(distinct b) from t where dt=xx "
> eg2:"select count(*),sum(a) ,count(distinct b) ,count(distinct c) from t
> where dt=xxx "
> eg3:"select count(distinct b), count(distinct c) from t where dt=xxx"
> eg1 will be right and have a query result as I expected , but eg2 will be
> wrong at the physical phase.The error info is here:
> https://gist.github.com/weijietong/1b8ed12db9490bf006e8b3fe0ee52269.
> eg3 will also get the similar error.
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