text: --  @testpoint:opengauss关键字message_octet_length(非保留)，自定义数据类型名为explain
  --关键字explain作为数据类型不带引号，创建成功
  drop type if exists message_octet_length;
  CREATE TYPE message_octet_length AS (f1 int, f2 text);
  select typname from pg_type where typname ='message_octet_length';
  drop type message_octet_length;
  
  
  --关键字explain作为数据类型加双引号，创建成功
  drop type if exists "message_octet_length";
  CREATE TYPE "message_octet_length" AS (f1 int, f2 text);
  select typname from pg_type where typname ='message_octet_length';
  drop type "message_octet_length";
  
  --关键字explain作为数据类型加单引号，合理报错
  drop type if exists 'message_octet_length';
  CREATE TYPE 'message_octet_length' AS (f1 int, f2 text);
  select * from pg_type where typname ='message_octet_length';
  drop type 'message_octet_length';
  
  --关键字explain作为数据类型加反引号，合理报错
  drop type if exists `message_octet_length`;
  CREATE TYPE `message_octet_length` AS (f1 int, f2 text);
  select * from pg_type where typname =`message_octet_length`;
  drop type `message_octet_length`;