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https://issues.apache.org/jira/browse/SPARK-8077?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Michael Armbrust resolved SPARK-8077.
-------------------------------------
Resolution: Fixed
Fix Version/s: 1.5.0
Issue resolved by pull request 6673
[https://github.com/apache/spark/pull/6673]
> Optimisation of TreeNode for large number of children
> -----------------------------------------------------
>
> Key: SPARK-8077
> URL: https://issues.apache.org/jira/browse/SPARK-8077
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 1.3.1
> Reporter: Mick Davies
> Priority: Minor
> Fix For: 1.5.0
>
>
> Large IN clauses are parsed very slowly. For example SQL below (10K items in
> IN) takes 45-50s.
> {code}
> s"""SELECT * FROM Person WHERE ForeName IN ('${(1 to 10000).map("n" +
> _).mkString("','")}')"""
> {code}
> This is principally due to TreeNode which repeatedly call contains on
> children, where children in this case is a List that is 10K long. In effect
> parsing for large IN clauses is O(N squared).
> A small change that uses a lazily initialised Set based on children for
> contains reduces parse time to around 2.5s
> I'd like to create PR for change, as we often use IN clauses with a few
> thousand items.
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