[CALCITE-3819] Prune parent RelNode when merging child RelSet with parent RelSet

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.23.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Haisheng Yuan
• Reporter: Haisheng Yuan
• Created: 25/Feb/20 04:31
• Updated: 24/May/20 12:00
• Resolved: 08/Mar/20 00:14

Description

Suppose we have 2 RelSets:
RelSet A: rel1
RelSet B: rel2

rel1 is the parent of rel2.

If there is a transformation rule that transform rel1 to rel2, we will merge RelSet A and B. During merge process, we can safely prune rel1 to avoid further rule apply on rel1 and reduce search space, more importantly, avoid cyclic reference.

Issue Links

• links to: GitHub Pull Request #1829
• links to: GitHub Pull Request #1888