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https://issues.apache.org/jira/browse/HIVE-5771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13977566#comment-13977566
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Hari Sankar Sivarama Subramaniyan commented on HIVE-5771:
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Hi [~tedxu] I have a minor comment on the implementation.
Is there a reason for these rules sharing same val.
+ opRules.put(new RuleRegExp("R5", "UNION%"), ConstantPropagateProcFactory
+ .getUnionProc());
+ opRules.put(new RuleRegExp("R5", "RS%"), ConstantPropagateProcFactory
+ .getReduceSinkProc());
Thanks
Hari
> Constant propagation optimizer for Hive
> ---------------------------------------
>
> Key: HIVE-5771
> URL: https://issues.apache.org/jira/browse/HIVE-5771
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Ted Xu
> Assignee: Ted Xu
> Attachments: HIVE-5771.1.patch, HIVE-5771.2.patch, HIVE-5771.3.patch,
> HIVE-5771.4.patch, HIVE-5771.5.patch, HIVE-5771.6.patch, HIVE-5771.7.patch,
> HIVE-5771.8.patch, HIVE-5771.patch
>
>
> Currently there is no constant folding/propagation optimizer, all expressions
> are evaluated at runtime.
> HIVE-2470 did a great job on evaluating constants on UDF initializing phase,
> however, it is still a runtime evaluation and it doesn't propagate constants
> from a subquery to outside.
> It may reduce I/O and accelerate process if we introduce such an optimizer.
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