python_sqlite_bug.py

import sqlite3
import os
import time

# showcase of a bug in the python version of sqlite3
# starting an insert with a comment will result in much slower performance and rowcount not being set properly

def test(with_comment):
	os.system('rm -f test.db')
	con = sqlite3.connect('test.db')
	c = con.cursor()

	start = time.time()
	c.execute('CREATE TABLE integers(i INTEGER)')
	if with_comment:
		insert_query = """
-- insert many values into the db
INSERT INTO integers VALUES ($1)
"""
	else:
		insert_query = 'INSERT INTO integers VALUES ($1)'
	c.executemany(insert_query, [(x,) for x in range(0, 10000)])
	print(c.rowcount)
	con.commit()
	end = time.time()
	return str(end - start)

# around ~0.01 seconds
print('normal executemany time: ' + test(False) + "s")
# around ~10 seconds
print('comment executemany time: ' + test(True) + "s")