presto-main/src/main/java/io/prestosql/operator/scalar/DataSizeFunctions.java/DataSizeFunctions/parseValue
class DataSizeFunctions:    private static BigDecimal parseValue(String value, String dataSize)
    {
        try {
            return new BigDecimal(value);
        }
        catch (NumberFormatException e) {
            throw invalidDataSize(dataSize);
        }
    }