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Posted to issues@spark.apache.org by "Jiang Xingbo (JIRA)" <ji...@apache.org> on 2016/07/01 09:09:10 UTC
[jira] [Created] (SPARK-16343) Improve the PushDownPredicate rule
to pushdown predicates currectly in non-deterministic condition
Jiang Xingbo created SPARK-16343:
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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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