# 使用的是aiiomysql库,autocommit是一个封装好的链接池,执行sql后会自动commit
# 这样还有其他细节,如果sql语句校验,重试等,不过与问题无关,就省略了
async with autocommit.acquire() as conn:
    async with conn.cursor() as cur:
        ret = await cur.execute(sql, param)
        res = await cur.fetchall()
        return ret, res

async with autocommit.acquire() as conn:
    async with conn.cursor() as cur:
        try:
        	ret = await cur.execute(sql, param)
        except aiomysql.OperationalError as e:
            await conn.ping()
        	ret = await cur.execute(sql, param)
        res = await cur.fetchall()
        return ret, res