remote exchange (GATHER, SINGLE, [])
    final aggregation over (ss_customer_sk, ss_item_sk, ss_sold_date_sk)
        local exchange (GATHER, SINGLE, [])
            partial aggregation over (ss_customer_sk, ss_item_sk, ss_sold_date_sk)
                scan store_sales_item_customer_solddate_buckarr2_buckcount3
