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From "Rong Rong (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-10474) Don't translate IN to JOIN with VALUES for streaming queries
Date Tue, 02 Oct 2018 15:14:00 GMT

    [ https://issues.apache.org/jira/browse/FLINK-10474?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16635666#comment-16635666
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Rong Rong commented on FLINK-10474:
-----------------------------------

Yes. I think having cascaded predicates are definitely not the best idea. 
However I was wondering if there's anything better we can do when we already knew the right
operand for the IN operation is static list of LITERALs, maybe we can replace it will a more
efficient scalar function? 

> Don't translate IN to JOIN with VALUES for streaming queries
> ------------------------------------------------------------
>
>                 Key: FLINK-10474
>                 URL: https://issues.apache.org/jira/browse/FLINK-10474
>             Project: Flink
>          Issue Type: Improvement
>          Components: Table API &amp; SQL
>    Affects Versions: 1.6.1, 1.7.0
>            Reporter: Fabian Hueske
>            Assignee: Hequn Cheng
>            Priority: Major
>
> IN clauses are translated to JOIN with VALUES if the number of elements in the IN clause
exceeds a certain threshold. This should not be done, because a streaming join is very heavy
and materializes both inputs (which is fine for the VALUES) input but not for the other.
> There are two ways to solve this:
>  # don't translate IN to a JOIN at all
>  # translate it to a JOIN but have a special join strategy if one input is bound and
final (non-updating)
> Option 1. should be easy to do, option 2. requires much more effort.



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