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https://issues.apache.org/jira/browse/DRILL-5691?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16141322#comment-16141322
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ASF GitHub Bot commented on DRILL-5691:
---------------------------------------
Github user amansinha100 commented on a diff in the pull request:
https://github.com/apache/drill/pull/889#discussion_r135199961
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/join/JoinUtils.java
---
@@ -231,6 +236,12 @@ public static boolean isScalarSubquery(RelNode root) {
return true;
}
}
+ if (!hasMoreInputs && currentRel != null) {
+ Double rowSize =
RelMetadataQuery.instance().getMaxRowCount(currentRel);
--- End diff --
Actually, I am thinking this entire method isScalarSubquery() should be
rewritten to call RelMetadataQuery.getMaxRowCount(). Originally, when this
was written, the max row count interface was not available.
I think your use case is somewhat specific that the table has 1 row.
However, suppose we had LIMIT 1 in the subquery, we could still treat it as
scalar since it would produce at most 1 row. My thought is instead of solving
for your specific table scan case, we might as well address the generalized
scalar check since Calcite already provides it.
> 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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