presto-main/src/main/java/io/prestosql/operator/aggregation/MaxDataSizeForStats.java/MaxDataSizeForStats/update
class MaxDataSizeForStats:    private static void update(NullableLongState state, long size)
    {
        if (state.isNull()) {
            state.setNull(false);
            state.setLong(size);
        }
        else {
            state.setLong(max(state.getLong(), size));
        }
    }