pub fn step_aggr_to_upper_aggr(
aggr_plan: &LogicalPlan,
) -> Result<[LogicalPlan; 2]>Expand description
generate the upper aggregation plan that will execute on the frontend. Basically a logical plan resembling the following: Projection: Aggregate:
from Aggregate
The upper Projection exists sole to make sure parent plan can recognize the output of the upper aggregation plan.