[CALCITE-3851] Replace the node importance map with a set for pruned nodes

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.23.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Chunwei Lei
• Reporter: Liya Fan
• Created: 10/Mar/20 12:52
• Updated: 24/May/20 11:59
• Resolved: 08/Apr/20 02:24

Description

Currently, volcano planner stores rel node importances with a map. In fact, the value of the map can only be 0.
So there is no need to store the values, and we replace the map with a set to store nodes whose importances are 0.

This makes the code logic clearer, and avoids instability caused by comparing floating point values.

Issue Links

• links to: GitHub Pull Request #1853