Sometimes it broke by concurrent.futures._base.CancelledError

[yanjieee]

When I using Aiomysql in a sanic high concurrency web server:

async with self._pool.acquire() as conn:
    async with conn.cursor() as cur:
        await cur.execute(query, param)
        if is_all:
            res = await cur.fetchall()
        else:
            res = await cur.fetchone()

Sometimes it broken this error:

Traceback (most recent call last):
  File "/usr/local/mycodes/amysql.py", line 249, in query
    res = await cur.fetchone()
  File "/usr/local/lib/python3.6/site-packages/aiomysql/utils.py", line 103, in __aexit__
    await self._pool.release(self._conn)
concurrent.futures._base.CancelledError

or

Traceback (most recent call last):
  File "/usr/local/mycodes/amysql.py", line 243, in query
    async with self._pool.acquire() as conn:
  File "/usr/local/lib/python3.6/site-packages/aiomysql/utils.py", line 98, in __aenter__
    self._conn = await self._coro
  File "/usr/local/lib/python3.6/site-packages/aiomysql/pool.py", line 133, in _acquire
    async with self._cond:
  File "/usr/lib64/python3.6/asyncio/locks.py", line 79, in __aenter__
    yield from self.acquire()
  File "/usr/lib64/python3.6/asyncio/locks.py", line 181, in acquire
    yield from fut
concurrent.futures._base.CancelledError

About 1000 request in 10 seconds will cause this error.
What can I do for avoiding this error?

[stolenzc]

I got the same error and I don‘t how to solve

[yanjieee]

I got the same error and I don‘t how to solve

实际上好像并没有什么影响，我现在这么处理：

        except asyncio.CancelledError:
            # 在高并发情况下，偶发该错误，但是res结果并无影响
            # google上建议把协程的CancelledError抛到上级协程一般处理
            self._log.warning("Concurrent CancelledError:{}".format(sql))
            raise

[stolenzc]

async def query_one(sql, args=(), size=None):
    async with _mysql_pool.acquire() as conn:
        try:
            await conn.ping(reconnect=True)
        except Exception:
            await conn._connect()
        async with conn.cursor(aiomysql.DictCursor) as cur:
            try:
                await cur.execute(sql, args)
                query = await cur.fetchone()
               # 通常在此之前抛出异常。导致事务未能提交，数据库会产生堆积sleep任务等待事务提交
            finally:
                await conn.commit()
            return query

我现在是这样一个函数，即使捕捉到了异常，也不能将此次事务查询完成

[flask-rabmq]

I got the same error and I don‘t how to solve.

[ShownYoung]

async def query_one(sql, args=(), size=None):
    async with _mysql_engine.acquire() as conn:
        
        trans = await conn.begin()
        
        try:
            await conn.execute(sql, args)
        except asyncio.CancelledError:
            # coroutine is canceled ，how to release the transaction？
            # will raise: Cannot release a connection with not finished transaction
            await trans.rollback()
        finally:
            await conn.commit()