text: --  @testpoint:opengauss关键字returned_octet_length(非保留)，作为用户名
  
  --关键字returned_octet_length作为用户名不带引号，创建成功
  drop user if exists returned_octet_length;
  CREATE USER returned_octet_length PASSWORD 'Bigdata@123';
  drop user returned_octet_length;
  
  --关键字returned_octet_length作为用户名加双引号，创建成功
  drop user if exists "returned_octet_length";
  CREATE USER "returned_octet_length" PASSWORD 'Bigdata@123';
  drop user "returned_octet_length";
   
  --关键字returned_octet_length作为用户名加单引号，合理报错
  CREATE USER 'returned_octet_length' PASSWORD 'Bigdata@123';
  
  --关键字returned_octet_length作为用户名加反引号，合理报错
  CREATE USER `returned_octet_length` PASSWORD 'Bigdata@123';
  