这似乎是pymssql的is_disconnect()方法中的错误，它忽略了TCP连接和超时失败，使光标处于不满意的状态；参见 http://www.sqlalchemy.org/trac/ticket/2172 .现在，您可以按照以下方式进行猴子补丁:

This seems to be a bug in the is_disconnect() method for pymssql where it ignore TCP connection and timeout failures, leaving the cursor in an unhappy state; see http://www.sqlalchemy.org/trac/ticket/2172. For now, you can monkey-patch as:

from sqlalchemy.dialects.mssql import pymssql

def is_disconnect(self, e):
    for msg in (
        "20003",
        "20004",
        "Error 10054",
        "Not connected to any MS SQL server",
        "Connection is closed"
        ):
        if msg in str(e):
            return True
    else:
        return False

pymssql.MSDialect_pymssql.is_disconnect = is_disconnect