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From "Piotr Nowojski (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-10474) Don't translate IN with Literals to JOIN with VALUES for streaming queries
Date Tue, 09 Oct 2018 11:12:00 GMT

    [ https://issues.apache.org/jira/browse/FLINK-10474?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16643130#comment-16643130
] 

Piotr Nowojski commented on FLINK-10474:
----------------------------------------

Yes, specialised operator might/should be quicker. I forgot about that. Still I would prefer
to focus on more general solution and only later optimise it, but we can do this other way
around as well.

> Don't translate IN with Literals 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
>              Labels: pull-request-available
>
> IN predicates with literals 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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