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Posted to issues@spark.apache.org by "Nattavut Sutyanyong (JIRA)" <ji...@apache.org> on 2016/08/08 16:28:20 UTC
[jira] [Updated] (SPARK-16951) Alternative implementation of NOT IN
to Anti-join
[ https://issues.apache.org/jira/browse/SPARK-16951?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Nattavut Sutyanyong updated SPARK-16951:
----------------------------------------
Description:
A transformation currently used to process {{NOT IN}} subquery is to rewrite to a form of Anti-join with null-aware property in the Logical Plan and then translate to a form of {{OR}} predicate joining the parent side and the subquery side of the {{NOT IN}}. As a result, the presence of {{OR}} predicate is limited to the nested-loop join execution plan, which will have a major performance implication if both sides' results are large.
This JIRA sketches an idea of changing the OR predicate to a form similar to the technique used in the implementation of the Existence join that addresses the problem of {{EXISTS (..) OR ..}} type of queries.
was:
A transformation currently used to process NOT IN subquery is to rewrite to a form of Anti-join with null-aware property in the Logical Plan and then translate to a form of OR predicate joining the parent side and the subquery side of the NOT IN. As a result, the presence of OR predicate is limited to the nested-loop join execution plan, which will have a major performance implication if both sides' results are large.
This JIRA sketches an idea of changing the OR predicate to a form similar to the technique used in the implementation of the Existence join that addresses the problem of EXISTS (..) OR .. type of queries.
> Alternative implementation of NOT IN to Anti-join
> -------------------------------------------------
>
> Key: SPARK-16951
> URL: https://issues.apache.org/jira/browse/SPARK-16951
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 2.0.0
> Reporter: Nattavut Sutyanyong
> Fix For: 2.1.0
>
>
> A transformation currently used to process {{NOT IN}} subquery is to rewrite to a form of Anti-join with null-aware property in the Logical Plan and then translate to a form of {{OR}} predicate joining the parent side and the subquery side of the {{NOT IN}}. As a result, the presence of {{OR}} predicate is limited to the nested-loop join execution plan, which will have a major performance implication if both sides' results are large.
> This JIRA sketches an idea of changing the OR predicate to a form similar to the technique used in the implementation of the Existence join that addresses the problem of {{EXISTS (..) OR ..}} type of queries.
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