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https://issues.apache.org/jira/browse/HAWQ-936?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15386950#comment-15386950
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ASF GitHub Bot commented on HAWQ-936:
-------------------------------------
Github user changleicn commented on the issue:
https://github.com/apache/incubator-hawq/pull/800
LGTM
> Add GUC for array expansion in ORCA optimizer
> ---------------------------------------------
>
> Key: HAWQ-936
> URL: https://issues.apache.org/jira/browse/HAWQ-936
> Project: Apache HAWQ
> Issue Type: New Feature
> Components: Optimizer
> Reporter: Haisheng Yuan
> Assignee: Venkatesh
> Fix For: 2.0.1.0-incubating
>
>
> Consider the query with the following pattern select * from foo where foo.a
> IN {1,2,3,...}. Currently, when the number of constants in the IN subquery is
> large, the query optimization time is unacceptable. This is stopping
> customers from turning Orca on by default since many of the queries are
> generated queries with such a pattern.
> The root cause is due to the expansion of the IN subquery into an expression
> in disjunctive normal form. The objective of this story is to disable this
> expansion when the number of constants in the IN list is large.
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