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https://issues.apache.org/jira/browse/TAJO-1277?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jihoon Son updated TAJO-1277:
-----------------------------
    Comment: was deleted

(was: No problem. :))

> GreedyHeuristicJoinOrderAlgorithm sometimes wrongly assumes associativity of 
> joins
> ----------------------------------------------------------------------------------
>
>                 Key: TAJO-1277
>                 URL: https://issues.apache.org/jira/browse/TAJO-1277
>             Project: Tajo
>          Issue Type: Bug
>            Reporter: Keuntae Park
>            Assignee: Keuntae Park
>
> It looks like GreedyHeuristicJoinOrderAlgorithm always assumes every joins 
> are associative.
> Following query returns in inaccurate result:
> {code}
> select * FROM
> customer c 
> right outer join nation n on c.c_custkey = n.n_nationkey
> join region r on c.c_custkey = r.r_regionkey;
> {code}
> because GreedyHeuristicJoinOrderAlgorithm changes join order as
> {code}
> select * FROM
> customer c 
> join region r on c.c_custkey = r.r_regionkey
> right outer join nation n on c.c_custkey = n.n_nationkey;
> {code}
> I think getBestPair() should be fixed to avoid wrong join ordering. 



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