[CALCITE-6043] The hintable RelNode should display hint's infomation in explainTerms method

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: LakeShen
• Created: 09/Oct/23 08:04
• Updated: 09/Oct/23 08:22

Description

Now in Calcite, almost all types of RelNode implement the Hintable interface, which means that this type of RelNode could do hint propagation and attach.

However, in these RelNodes which implements the Hintable interface, their `explainTerms` method does not display hint information.When users viewing a RelNode plan tree,this will cause users who use Calcite's hint don't know what each RelNode Hint is,such as using the `RelOptUtil.toString` method to display the RelNode tree.

So I propose to add hints information in the `explainTerms` method of RelNode that implements Hintable interface.In this way, users who use Calcite can easily know the information of Hint, and it is also convenient for them to debug Hint.

This proposal will minimize adding hint information in the `explainTerms` method of common RelNode.