Eval distinct aggregate functions with distinct input arrange
return distinct rows(distinct by row’s key) from the input, but do not update the arrangement
Eval simple aggregate functions with no distinct input
convert a list of accumulators to a vector of values with first value as offset of end of each accumulator
Convert a value to a list of slice index
eval accumulable reduce plan by eval aggregate function and reduce the result
eval distinct reduce plan, output the distinct, and update the arrangement
reduce subgraph, reduce the input data into a single row
output is concat from key and val
split a row into key and val by evaluate the key and val plan
eval distinct reduce plan, output the distinct, and update the arrangement