使用dmpython连接达梦集群数据库，首次连接可以查询并成功返回，再次连接时，再也连接不上了。

写了一个连接类

import dmPython
import traceback

class DaMengDBClient:
    def __init__(self, host, user, pwd):
        self.host = host
        self.user = user
        self.pwd = pwd
        self.collectionstrurl = "%s/%s@%s" % (self.user, self.pwd, self.host)

    def __enter__(self):
        try:
            self.cnxn = dmPython.connect(self.collectionstrurl)
            self.cursor = self.cnxn.cursor()
            return self
        except Exception as e:
            print(e)
            print('数据库连接失败！')
            print(traceback.format_exc())

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.cursor.close()
        self.cnxn.close()

if __name__ == '__main__':
    host = 'DamengDSC'
    user = 'test'
    pwd = '123456'

    with DaMengDBClient(host=host, user=user, pwd=pwd) as oc:
        sql = 'select * from "test"'
        # 执行SQL语句
        values = oc.cursor.execute(sql).fetchall()
        print(values)

第一次成功后，第二次
报错：[-70028]:创建 SOCKET 连接失败