GitHub user MickDavies reopened a pull request:
https://github.com/apache/spark/pull/6673
[SPARK-8077][SQL] Optimization for TreeNodes with large numbers of children
For example large IN clauses
Large IN clauses are parsed very slowly. For example SQL below (10K items
in IN) takes 45-50s.
s"""SELECT * FROM Person WHERE ForeName IN ('${(1 to 10000).map("n" +
_).mkString("','")}')"""
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 lazily initialised Set based on children for contains reduces parse time
to around 2.5s
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/MickDavies/spark SPARK-8077
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/6673.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #6673
----
commit e6be8beb72936bb457343e6c9bd0dfddeede040f
Author: Michael Davies <[email protected]>
Date: 2015-06-05T18:02:15Z
SPARK-8077: Optimization for TreeNodes with large numbers of children
For example large IN clauses
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