Move the Horizon Planning to the Operators

[frouioui]

Feature Description

We would like to gradually move all the horizon planning work to the operators instead of the logical plan.

A horizon is what we call in the planner the stuff that is outside the FROM ... WHERE clause. If we are able to send the whole query to a single shard, we don't do much more planning - we simply add the rest of the clauses (projections, ordering, limit, aggregation and more) to the query and we are done.

If we can't delegate everything to MySQL, we do more planning, and this is what we call horizon planning.

Tracking

• Move horizon planning to operators #11622
• planner operators refactoring #11680
• Horizon planning on operators #12506
• [gen4 planner] Move more horizon planning to operators #12750

[frouioui]

Duplicate of #11626