pub fn lower(layout: &LayoutRef) -> VortexResult<PlanRef>Expand description
Lowers layout into a physical plan.
Zoned and legacy stats layouts keep their zone statistics: unoptimized they read only their data, and the optimizer rewrites a statistics predicate over them into a pruning plan. Those with no zones or no statistics lower to their data.
The root operator is built immediately. Its child container owns a hidden clone of the source layout and lowers each child independently on first access.
A flat layout lowers to a Filter over its segment scan, so
the scan returns only the rows it is executed with.