【原文链接】MySQL----MySQL数据库出现Lost connection to MySQL server during query错误的解决办法

问题描述

Mysql数据库在查询数据库的时候回报出了如下异常：Lost connection to MySQL Server during query，具体异常信息如下：

Traceback (most recent call last):  File "/opt/mugen/run_mugen.py", line 883, in run_testsuit    env = get_env(testsuit_name)  File "/opt/mugen/run_mugen.py", line 751, in get_env    row = session.query(Testsuit).filter(Testsuit.name == testsuit_name).first()  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/ORM/query.py", line 2752, in first    return self.limit(1)._iter().first()  # type: ignore  File "/usr/local/Python3/lib/python3.9/site-packages/sqlalchemy/orm/query.py", line 2855, in _iter    result: UNIOn[ScalarResult[_T], Result[_T]] = self.session.execute(  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/orm/session.py", line 2229, in execute    return self._execute_internal(  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/orm/session.py", line 2114, in _execute_internal    conn = self._connection_for_bind(bind)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/orm/session.py", line 1981, in _connection_for_bind    return trans._connection_for_bind(engine, execution_options)  File "", line 2, in _connection_for_bind  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/orm/state_changes.py", line 137, in _Go    ret_value = fn(self, *arg, **kw)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/orm/session.py", line 1108, in _connection_for_bind    conn = bind.connect()  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3251, in connect    return self._connection_cls(self)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 147, in __init__    Connection._handle_dbapi_exception_noconnection(  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2413, in _handle_dbapi_exception_noconnection    raise sqlalchemy_exception.with_traceback(exc_info[2]) from e  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 145, in __init__    self._dbapi_connection = engine.raw_connection()  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3275, in raw_connection    return self.pool.connect()  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 455, in connect    return _ConnectionFairy._checkout(self)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 1271, in _checkout    fairy = _ConnectionRecord.checkout(pool)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 725, in checkout    rec._checkin_failed(err, _fairy_was_created=False)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 147, in __exit__    raise exc_value.with_traceback(exc_tb)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 722, in checkout    dbapi_connection = rec.get_connection()  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 842, in get_connection    self.__connect()  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 906, in __connect    pool.logger.debug("Error on connect(): %s", e)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 147, in __exit__    raise exc_value.with_traceback(exc_tb)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 901, in __connect    self.dbapi_connection = connection = pool._invoke_creator(self)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/engine/create.py", line 640, in connect    return dialect.connect(*cargs, **cparams)  File "/usr/local/python3/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 580, in connect    return self.loaded_dbapi.connect(*cargs, **cparams)  File "/usr/local/python3/lib/python3.9/site-packages/pymysql/connections.py", line 353, in __init__    self.connect()  File "/usr/local/python3/lib/python3.9/site-packages/pymysql/connections.py", line 633, in connect    self._request_authentication()  File "/usr/local/python3/lib/python3.9/site-packages/pymysql/connections.py", line 907, in _request_authentication    auth_packet = self._read_packet()  File "/usr/local/python3/lib/python3.9/site-packages/pymysql/connections.py", line 692, in _read_packet    packet_header = self._read_bytes(4)  File "/usr/local/python3/lib/python3.9/site-packages/pymysql/connections.py", line 748, in _read_bytes    raise err.OperationalError(sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (2013, 'Lost connection to MySQL server during query')

解决办法：

在数据库中查看如下变量的值

可以看到这里的net_read_timeout和net_write_timeout分别为30和60秒，首先将这两个参数修改为更大一点的值。比如修改为300和900。如下所示，这里需要注意的是修改的时候需要分别设置global和session级别的，然后才会生效。

来源地址：https://blog.csdn.net/redrose2100/article/details/130909059