presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/PushPartialAggregationThroughJoin.java/PushPartialAggregationThroughJoin/isSupportedAggregationNode
class PushPartialAggregationThroughJoin:    private static boolean isSupportedAggregationNode(AggregationNode aggregationNode)
    {
        // Don't split streaming aggregations
        if (aggregationNode.isStreamable()) {
            return false;
        }

        if (aggregationNode.getHashSymbol().isPresent()) {
            // TODO: add support for hash symbol in aggregation node
            return false;
        }
        return aggregationNode.getStep() == PARTIAL && aggregationNode.getGroupingSetCount() == 1;
    }