[CALCITE-4466] Do not RelTraitDef.convert if the "from" trait already satisfies the "to" trait.

• Type: Task
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.26.0
• Fix Version/s: 1.27.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Vladimir Ozerov
• Reporter: Vladimir Ozerov
• Created: 13/Jan/21 15:49
• Updated: 03/Jun/21 22:31
• Resolved: 22/Jan/21 04:50

Description

Consider that we have two trait defs A_def and B_def. We have a node with the trait set [A_from, B_from] that we want to convert to a node with the traits set [A_to, B_to]. Suppose that:

• A_from.satisfies(A_to) = false
• B_from.satisfies(B_to) = true

Currently, the VolcanoPlanner will invoke convert on both A_trait and B_trait, because it skips the conversion only when two traits are equal. In our example, it will lead to an unnecessary call to B_def.convert(node, B_to). This is not a big problem but it forces implementors of custom traits to double-check whether the passed node already satisfies the required trait or not.

The proposal is to replace fromTrait.equals(toTrait) with fromTrait.satisfies(toTrait).

Issue Links

• links to: GitHub Pull Request #2325