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From "Apache Spark (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (SPARK-19408) cardinality estimation involving two columns of the same table
Date Fri, 24 Mar 2017 20:55:41 GMT

    [ https://issues.apache.org/jira/browse/SPARK-19408?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15941117#comment-15941117
] 

Apache Spark commented on SPARK-19408:
--------------------------------------

User 'ron8hu' has created a pull request for this issue:
https://github.com/apache/spark/pull/17415

> cardinality estimation involving two columns of the same table
> --------------------------------------------------------------
>
>                 Key: SPARK-19408
>                 URL: https://issues.apache.org/jira/browse/SPARK-19408
>             Project: Spark
>          Issue Type: Sub-task
>          Components: Optimizer
>    Affects Versions: 2.1.0
>            Reporter: Ron Hu
>
> In SPARK-17075, we estimate cardinality of predicate expression "column (op) literal",
where op is =, <, <=, >, or >=.  In SQL queries, we also see predicate expressions
involving two columns such as "column-1 (op) column-2" where column-1 and column-2 belong
to same table.  Note that, if column-1 and column-2 belong to different tables, then it is
a join operator's work, NOT a filter operator's work.
> In this jira, we want to estimate the filter factor of predicate expressions involving
two columns of same table.   



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