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From "Jiang Xingbo (JIRA)" <j...@apache.org>
Subject [jira] [Created] (SPARK-16343) Improve the PushDownPredicate rule to pushdown predicates currectly in non-deterministic condition
Date Fri, 01 Jul 2016 09:09:10 GMT
Jiang Xingbo created SPARK-16343:
------------------------------------

             Summary: 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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