[TRAFODION-2127] enhance Trafodion implementation of WITH clause

• Type: Improvement
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Assignee: Hans Zeller
• Reporter: liu ming
• Created: 24/Jul/16 02:16
• Updated: 05/Mar/18 17:39

Description

TRAFODION-1673 described some details about how to support WITH clause in Trafodion.
As initial implementation, we use a simple pure-parser method.
That way, Trafodion can support WITH clause functionally, but not good from performance point of view,
also need to enhance the parser to be more strict in syntax.
This JIRA is a follow up JIRA, to track following effort to support Trafodion WITH clause.

Issue Links

• Blocked: TRAFODION-1673 Implement the WITH clause in Trafodion SQL for simple use cases
• links to: GitHub Pull Request #772

Sub-Tasks

• Implement relational operator for common subexpressions and transformation: Closed
• Implement use of volatile tables for WITH clause and common subexpressions: Open
• Heuristic decision on when to use a temp table for WITH clause: Closed
• Make subquery unnesting work with common subexpressions: Closed
• Fix other issues related to statement reuse and Hive tables in CSEs: Open
• Solve issue with mapping of value ids for statistics for common subexpr: Open