presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/PushPartialAggregationThroughExchange.java/PushPartialAggregationThroughExchange/getPattern
class PushPartialAggregationThroughExchange:    @Override
    public Pattern<AggregationNode> getPattern()
    {
        return PATTERN;
    }