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https://issues.apache.org/jira/browse/SPARK-20104?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wenchen Fan reassigned SPARK-20104:
-----------------------------------
Assignee: Zhenhua Wang
> Don't estimate IsNull or IsNotNull predicates for non-leaf node
> ---------------------------------------------------------------
>
> Key: SPARK-20104
> URL: https://issues.apache.org/jira/browse/SPARK-20104
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.2.0
> Reporter: Zhenhua Wang
> Assignee: Zhenhua Wang
> Fix For: 2.2.0
>
>
> In current stage, we don't have advanced statistics such as sketches or
> histograms. As a result, some operator can't estimate `nullCount` accurately.
> E.g. left outer join estimation does not accurately update `nullCount`
> currently. So for IsNull and IsNotNull predicates, we only estimate them when
> the child is a leaf node, whose `nullCount` is accurate.
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