python sqlalchemy 连接mysql并发查询报错 2006, 2013, 2014, 2045, 2055

直接上代码：

from MySQLdb.constants.CLIENT import MULTI_STATEMENTS, MULTI_RESULTS
from sqlalchemy import create_engine, event
from sqlalchemy.exc import DisconnectionError
from connection.connect import Connect

engine_mysql = create_engine("mysql+mysqldb://{}:{}@{}/{}".format(
    MYSQL_SERVER_USER,
    MYSQL_SERVER_PASS,
    MYSQL_SERVER_ADDRESS,
    MYSQL_DATABASE_NAME), pool_timeout=60,
    connect_args={'charset': 'utf8', 'autocommit': 'true', 'client_flag': MULTI_STATEMENTS | MULTI_RESULTS}, echo=True,
    max_overflow=20,
    pool_size=100, pool_recycle=10, echo_pool=True)


# 主要在这里，添加Listener 每次访问前做验证是否连接
def checkout_listener(dbapi_con, con_record, con_proxy):
    try:
        try:
            dbapi_con.ping(False)
        except TypeError:
            dbapi_con.ping()
    except dbapi_con.OperationalError as exc:
        if exc.args[0] in (2006, 2013, 2014, 2045, 2055):
            raise DisconnectionError()
        else:
            raise


event.listen(engine_mysql, 'checkout', checkout_listener)