[CALCITE-2621] Add rule to execute semi joins with correlation

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.19.0
• Labels: pull-request-available
• Assignee: Ruben Quesada Lopez
• Reporter: Ruben Quesada Lopez
• Created: 11/Oct/18 09:23
• Updated: 25/Mar/19 00:11
• Resolved: 05/Mar/19 16:11

Description

Similarly to JoinToCorrelateRule, in some contexts it might be interesting to transform a SemiJoin into a LogicalCorrelate, for this purpose a SemiJoinToCorrelateRule will be needed.

This feature requires the fix CALCITE-2605, otherwise we would get an exception in EnumerableCorrelate#implement when trying to generate the Expression selector:

Caused by: java.lang.IllegalStateException: Unable to convert SEMI to JoinRelType
	at org.apache.calcite.sql.SemiJoinType.toJoinType(SemiJoinType.java:83)
	at org.apache.calcite.adapter.enumerable.EnumerableCorrelate.implement(EnumerableCorrelate.java:103)
        ...

Issue Links

• is blocked by: CALCITE-2605 NullPointerException when left outer join implemented with EnumerableCorrelate
• links to: GitHub Pull Request #884