presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/PushPartialAggregationThroughJoin.java/PushPartialAggregationThroughJoin/replaceAggregationSource
class PushPartialAggregationThroughJoin:    private AggregationNode replaceAggregationSource(
            AggregationNode aggregation,
            PlanNode source,
            List<Symbol> groupingKeys)
    {
        return new AggregationNode(
                aggregation.getId(),
                source,
                aggregation.getAggregations(),
                singleGroupingSet(groupingKeys),
                ImmutableList.of(),
                aggregation.getStep(),
                aggregation.getHashSymbol(),
                aggregation.getGroupIdSymbol());
    }