[CALCITE-3713] Remove column names from Project#digest

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.21.0
• Fix Version/s: 1.22.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Vladimir Sitnikov
• Reporter: Vladimir Sitnikov
• Created: 06/Jan/20 20:18
• Updated: 06/Mar/20 07:36
• Resolved: 12/Feb/20 03:14

Description

Projects that differ with column names only are equivalent, so the planning space can be reduced if field names do not participate in relation matching.

For instance, Project(input=rel#1,empid=$0) and Project(input=rel#1,deptno=$0) are equivalent

Issue Links

• relates to: CALCITE-3793 AssertionError throws for planner digest cache key when the rel type is not struct
• relates to: CALCITE-3795 Promote the Project digest to only print "0" instead of "0..0" when there is only one trivial field
• links to: GitHub Pull Request #1740