如何实现python3实现并发访问水平切分表

本篇文章给大家带来的内容是关于如何实现python3实现并发访问水平切分表，有一定的参考价值，有需要的朋友可以参考一下，希望对你有所帮助。场景说明假设有一个mysql表被水平切分，分散到多个host中，每个host拥有n个切分表。 如果需要并发去访问这些表，快速得到查询结果， 应该怎么做呢？ 这里提供一种方案，利用python3的asyncio异步io库及aiomysql异步库去实现这个需求。代码演示import loggingimport randomimport asynciofrom aiomysql import create_pool# 假设mysql表分散在8个host, 每个host有16张子表TBLES = {"192.168.1.01": "table_000-015", # 000-015表示该ip下的表明从table_000一直连续到table_015"192.168.1.02": "table_016-031","192.168.1.03": "table_032-047","192.168.1.04": "table_048-063","192.168.1.05": "table_064-079","192.168.1.06": "table_080-095","192.168.1.07": "table_096-0111","192.168.1.08": "table_112-0127",}USER = "xxx"PASSWD = "xxxx"# wrapper函数，用于捕捉异常def query_wrapper(func):async def wrapper(*args, **kwargs):try:await func(*args, **kwargs)except Exception as e:print(e)return wrapper# 实际的sql访问处理函数，通过aiomysql实现异步非阻塞请求@query_wrapperasync def query_do_something(ip, db, table):async with create_pool(host=ip, db=db, user=USER, password=PASSWD) as pool:async with pool.get() as conn:async with conn.cursor() as cur:sql = ("select xxx from {} where xxxx")await cur.execute(sql.format(table))res = await cur.fetchall()# then do something...# 生成sql访问队列, 队列的每个元素包含要对某个表进行访问的函数及参数def gen_tasks():tasks = []for ip, tbls in TBLES.items():cols = re.split('_|-', tbls)tblpre = "_".join(cols[:-2])min_num = int(cols[-2])max_num = int(cols[-1])for num in range(min_num, max_num+1):tasks.append((query_do_something, ip, 'your_dbname', '{}_{}'.format(tblpre, num)))random.shuffle(tasks)return tasks# 按批量运行sql访问请求队列def run_tasks(tasks, batch_len):try:for idx in range(0, len(tasks), batch_len):batch_tasks = tasks[idx:idx+batch_len]logging.info("current batch, start_idx:%s len:%s" % (idx, len(batch_tasks)))for i in range(0, len(batch_tasks)):l = batch_tasks[i]batch_tasks[i] = asyncio.ensure_future(l[0](*l[1:]))loop.run_until_complete(asyncio.gather(*batch_tasks))except Exception as e:logging.warn(e)# main方法, 通过asyncio实现函数异步调用def main():loop = asyncio.get_event_loop()tasks = gen_tasks()batch_len = len(TBLES.keys()) * 5# all up to yourun_tasks(tasks, batch_len)loop.close()以上就是如何实现python3实现并发访问水平切分表的详细内容，更多请关注小潘博客其它相关文章！