[jira] [Assigned] (TAJO-742) (Umbrella) Theta join support

["Jaehwa Jung (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TAJO-742?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jaehwa Jung reassigned TAJO-742:
--------------------------------

    Assignee:     (was: Jaehwa Jung)

> (Umbrella) Theta join support
> -----------------------------
>
>                 Key: TAJO-742
>                 URL: https://issues.apache.org/jira/browse/TAJO-742
>             Project: Tajo
>          Issue Type: Improvement
>          Components: physical operator
>            Reporter: Jaehwa Jung
>
> Currently, Tajo supports only equi-join. In contrast, theta-joins (not equality join) are used in many real applications. We need to support theta-joins in Tajo.
> If a join condition includes anything other than equality predicate "=", we call the join *theta join*. The predicates can be as follows:
>  * >, >=, <, <=, !=, LIKE. RLIKE, ...
> Basically, some predicates can exploit hash shuffle, range shuffle, or other thing. Other predicates requires that only one node processes all intermediate data by using BNL. Also, if a join condition is a mixed of equi-join and theta-join conditions, this join can make use of hash shuffle. This issue requires some investigation. 
> This is an umbrella issue. We'll create subtasks.



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