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Posted to dev@hawq.apache.org by "Haisheng Yuan (JIRA)" <ji...@apache.org> on 2016/07/18 23:36:20 UTC
[jira] [Created] (HAWQ-936) Add GUC for array expansion in ORCA
optimizer
Haisheng Yuan created HAWQ-936:
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Summary: 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
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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