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Posted to issues@spark.apache.org by "Zhenhua Wang (JIRA)" <ji...@apache.org> on 2017/01/25 01:01:27 UTC

[jira] [Updated] (SPARK-19350) Cardinality estimation of Limit and Sample

     [ https://issues.apache.org/jira/browse/SPARK-19350?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zhenhua Wang updated SPARK-19350:
---------------------------------
    Summary: Cardinality estimation of Limit and Sample  (was: Improve cardinality estimation of Limit and Sample)

> Cardinality estimation of Limit and Sample
> ------------------------------------------
>
>                 Key: SPARK-19350
>                 URL: https://issues.apache.org/jira/browse/SPARK-19350
>             Project: Spark
>          Issue Type: Sub-task
>          Components: SQL
>            Reporter: Zhenhua Wang
>
> Now we can easily get rowCount in Statistics for Limit and Sample whether cbo is enabled or not. But column stats should not be propagated because we don't know the distribution of columns after Limit or Sample.



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