Keuntae Park created TAJO-1277:
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Summary: 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
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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