import numpy as np
import pandas as pd
import pyarrow as pa

type_ = np.dtype('float64')
DATA_SIZE = (1 << 30)
NCOLS = 100
NROWS = DATA_SIZE / NCOLS / np.dtype(type_).itemsize

data = {
    'c' + str(i): np.random.randn(NROWS)
    for i in range(NCOLS)
}