为啥线程数不同,秒杀结果不同,好想知道这个具体原理啊.麻烦老师解答一下.具体看以下代码和截图

import redis
import random
from concurrent.futures import ThreadPoolExecutor

# 模拟抢购
pool = redis.ConnectionPool(host='localhost', port=6379, password=123, db=0, max_connections=20)
con = redis.Redis(connection_pool=pool)
con_buy = redis.Redis(connection_pool=pool)
# Python 线程池
executor = ThreadPoolExecutor(200)


def get_user_id():
    """ 创建user id 的集合"""
    s = set()
    while True:
        if len(s) == 1000:
            break
        num = random.randint(100000, 999999)
        s.add(num)
    return s


def buy():
    """ 模拟购买场景 """
    try:
        pipline = con_buy.pipeline()
        if con_buy.exists('kill_flag') == 1:
            pipline.watch('kill_flag', 'kill_user')
            total = int(pipline.get('kill_total').decode('utf-8'))
            # print(total)
            num = int(pipline.get('kill_num').decode('utf-8'))
            # print(num)
            if num < total:
                pipline.multi()
                pipline.incr('kill_num')
                s = get_user_id()
                user_id = s.pop()
                pipline.rpush('kill_user', user_id)
                pipline.execute()
                print('第{0}个秒杀成功,总共有{1},还有{2}个'.format(num+1, total, total-num-1))
    # except Exception as e:
    #     print(e)
    finally:
        pipline.reset()


def main():
    try:
        con.delete('kill_total', 'kill_num', 'kill_flag', 'kill_user')
        con.set('kill_total', 50)
        con.set('kill_num', 0)
        con.set('kill_flag', 1)
        con.expire('kill_flag', 600)
        for i in range(1000):
            executor.submit(buy)
        print("秒杀结束")

    except Exception as e:
        print(e)
    # finally:
    #     # del con
    #     del con_buy


if __name__ == '__main__':
    main()

我之前用200个线程总是抢不完, 换了线程总数,终于可以了,然后就测试了一下,发现,不同的线程数,结果截然不同.这是为啥呢??麻烦老师解答一下.以上的代码只是在线程数那里做了修改,其它地方都没改变.我的数据库也是和这个打印效果完全一样..