[jira] [Created] (TAJO-853) Refactoring FilterPushDown for OUTER JOIN

["Hyoungjun Kim (JIRA)" <ji...@apache.org>]

Hyoungjun Kim created TAJO-853:
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             Summary: Refactoring FilterPushDown for OUTER JOIN
                 Key: TAJO-853
                 URL: https://issues.apache.org/jira/browse/TAJO-853
             Project: Tajo
          Issue Type: Improvement
            Reporter: Hyoungjun Kim
            Assignee: Hyoungjun Kim
            Priority: Minor


Currently Tajo doesn't support a filter OUTER JOIN's ON clause.
or has some bugs. There is some rules for this in the following urls.
- http://www.ibm.com/developerworks/data/library/techarticle/purcell/0112purcell.html
- https://cwiki.apache.org/confluence/display/Hive/OuterJoinBehavior

Briefly summarized as follows.
- Join Predicate on Preserved Row Table: Used for join condition(not filter)
- Join Predicate on Null Supplying Table: Can push down to the table scan
- Where Predicate on Preserved Row Table: Can push down to the table scan
- Where Predicate on Null Supplying Table: Used for filter with join result data. This filter condition is attached to SELECTION Node.



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