[TRAFODION-2317] Implement relational operator for common subexpressions and transformation

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Affects Version/s: 2.1-incubating
• Fix Version/s: 2.2.0
• Component/s: sql-cmp
• Assignee: Hans Zeller
• Reporter: Hans Zeller
• Created: 27/Oct/16 01:58
• Updated: 22/May/17 16:38
• Resolved: 31/Oct/16 23:09

Description

This subtask provides the infrastructure for handling common subexpressions:

• A relational CommonSubExprRef operator to track the locations of common subexpressions in the query tree.
• Methods to analyze the common subexpressions in the tree and to determine whether a transformation is possible and what the temporary table would look like.
• Methods to do the actual query tree transformation.
• Some needed changes in bookkeeping and runtime.

Issue Links

• links to: GitHub Pull Request #794