json, bson, sqlite3 IOの実験メモ

import json
import random
import time

file = 'test.tmp'
N = 500

# Generate
start = time.time()
entries = []
for i in range(N):
    title = ''.join([
        chr(random.randint(ord('あ'), ord('ん')+1)) for i in range(32)
    ])
    body = ''.join([
        chr(random.randint(ord('あ'), ord('ん')+1)) for i in range(30000)
    ])

    entries.append({
        'id': i,
        'title': title,
        'body': body,
    })

data = {
    'entries': entries,
}

end = time.time()
print('Generate: %.1fs' % (end - start, ))

Generate: 38.6s

import os

# Write
start = time.time()
with open(file, 'w', encoding='utf-8') as fp:
    json.dump(data, fp, ensure_ascii=False)

end = time.time()
print('Write: %.3fs' % (end - start, ))

print('%.2fMB' % (os.path.getsize(file)/(1024**2), ))

# Read
start = time.time()
with open(file, 'r', encoding='utf-8') as fp:
    data = json.load(fp)

end = time.time()
print('Read: %.3fs' % (end - start, ))

Write: 0.252s
42.98MB
Read: 0.214s

pip install bson

import bson

# Write
start = time.time()
s = bson.dumps(data)
print('%.2fMB' % (len(s)/(1024**2), ))

dumpEnd = time.time()

with open(file, 'wb') as fp:
    fp.write(s)

end = time.time()

print('Write: %.3fs (Dump: %.3fs)' % (end - start, dumpEnd - start))


# Read
start = time.time()

with open(file, 'rb') as fp:
    s = fp.read()

loadStart = time.time()

data = bson.loads(s)
end = time.time()

print('Read: %.3fs (Load: %.3fs)' % (end - start, end - loadStart))

42.98MB
Write: 0.830s (Dump: 0.638s)
Read: 0.156s (Load: 0.095s)

import sqlite3

if os.path.exists(file):
    os.unlink(file)

start = time.time()
with sqlite3.connect(file) as db:
    cur = db.cursor()

    cur.execute(
        'CREATE TABLE entries(id INTEGER AUTO INCREMENT, title TEXT, body TEXT)'
    )
    for entry in data['entries']:
        cur.execute(
            'INSERT INTO entries VALUES(?,?,?)',
            (
                entry['id'],
                entry['title'],
                entry['body'],
            ),
        )
    
end = time.time()

print('Write: %.3fs' % (end - start, ))

start = time.time()
with sqlite3.connect(file) as db:
    cur = db.cursor()

    results = []
    for row in cur.execute('SELECT * FROM entries'):
        results.append(row)

end = time.time()

print('Read: %.3fs' % (end - start, ))


print('%.2fMB' % (os.path.getsize(file)/(1024**2), ))

db.close()

Write: 1.093s
Read: 0.243s
43.22MB