[TRAFODION-2320] Make subquery unnesting work with common subexpressions

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 2.1-incubating
• Component/s: sql-cmp
• Assignee: Hans Zeller
• Reporter: Hans Zeller
• Created: 27/Oct/16 19:34
• Updated: 22/May/17 16:38
• Resolved: 04/Jan/17 00:03

Description

The subquery unnesting code relies on a certain structure of the query tree, with join and groupby nodes arranged in a certain way. If we have CommonSubExprRef nodes present in the tree, the unnesting logic doesn't recognize some of the patterns and subquery unnesting doesn't take place.

Hopefully we can somehow ignore these extra nodes in subquery unnesting.