text: --  @testpoint:opengauss关键字maxvalue(保留)，作为角色名
  
  --关键字不带引号-合理报错
  drop role if exists maxvalue;
  create role maxvalue with password 'gauss@123' valid until '2020-12-31';
  
  --关键字带双引号-成功
  drop role if exists "maxvalue";
  create role "maxvalue" with password 'gauss@123' valid until '2020-12-31';
  
  --清理环境
  drop role "maxvalue";
  
  --关键字带单引号-合理报错
  drop role if exists 'maxvalue';
  create role 'maxvalue' with password 'gauss@123' valid until '2020-12-31';
  
  --关键字带反引号-合理报错
  drop role if exists `maxvalue`;
  create role `maxvalue` with password 'gauss@123' valid until '2020-12-31';