[TAJO-853] Refactoring FilterPushDown for OUTER JOIN

• Type: Improvement
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 0.9.0
• Assignee: Hyoungjun Kim
• Reporter: Hyoungjun Kim
• Created: 27/May/14 15:59
• Updated: 24/Jun/14 07:54
• Resolved: 24/Jun/14 07:00

Description

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.