presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/PushPartialAggregationThroughJoin.java/PushPartialAggregationThroughJoin/pushPartialToRightChild
class PushPartialAggregationThroughJoin:    private PlanNode pushPartialToRightChild(AggregationNode node, JoinNode child, Context context)
    {
        Set<Symbol> joinRightChildSymbols = ImmutableSet.copyOf(child.getRight().getOutputSymbols());
        List<Symbol> groupingSet = getPushedDownGroupingSet(node, joinRightChildSymbols, intersection(getJoinRequiredSymbols(child), joinRightChildSymbols));
        AggregationNode pushedAggregation = replaceAggregationSource(node, child.getRight(), groupingSet);
        return pushPartialToJoin(node, child, child.getLeft(), pushedAggregation, context);
    }