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From "Apache Spark (JIRA)" <j...@apache.org>
Subject [jira] [Assigned] (SPARK-16343) Improve the PushDownPredicate rule to pushdown predicates currectly in non-deterministic condition
Date Fri, 01 Jul 2016 09:18:11 GMT

     [ https://issues.apache.org/jira/browse/SPARK-16343?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Apache Spark reassigned SPARK-16343:
------------------------------------

    Assignee:     (was: Apache Spark)

> Improve the PushDownPredicate rule to pushdown predicates currectly in non-deterministic
condition
> --------------------------------------------------------------------------------------------------
>
>                 Key: SPARK-16343
>                 URL: https://issues.apache.org/jira/browse/SPARK-16343
>             Project: Spark
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 1.6.2
>            Reporter: Jiang Xingbo
>            Priority: Critical
>
> Currently our Optimizer may reorder the predicates to run them more efficient, but in
non-deterministic condition, change the order between deterministic parts and non-deterministic
parts may change the number of input rows. For example:
> {code:sql}
> SELECT a FROM t WHERE rand() < 0.1 AND a = 1
> {code}
> And
> {code:sql}
> SELECT a FROM t WHERE a = 1 AND rand() < 0.1
> {code}
> may call rand() for different times and therefore the output rows differ.



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