sorrow.py

import os
import random
import threading
import sqlite3


class W(threading.Thread):

    def __init__(self, connection):
        super(W, self).__init__()
        self.daemon = False
        self.connection = connection

    def run(self):
        while True:
            os.write(1, "w")
            cursor = self.connection.cursor()
            with self.connection:
                cursor.execute(
                    '''
                    INSERT INTO T values (?)
                    ''',
                    (random.randint(0, 100),))


class R(threading.Thread):

    def __init__(self, connection):
        super(R, self).__init__()
        self.daemon = False
        self.connection = connection

    def run(self):
        while True:
            os.write(1, "r")
            self.connection.execute(
                '''
                SELECT * FROM T LIMIT 1
                ''').fetchall()


connection = sqlite3.connect('/tmp/db.sqlite3',
                             check_same_thread=False)
connection.executescript('CREATE TABLE IF NOT EXISTS T (thing INTEGER)')


writers = [W(connection) for _ in range(10)]
readers = [R(connection) for _ in range(10)]

for w in writers:
    w.start()

for r in readers:
    r.start()