[HCS]集群数据库用户管理查询等操作超时

1、问题背景：集群的数据库用户管理功能操作耗时较长

2、浏览器按F12进入调试模式发现请求报错超时，根据业务逻辑是使用rpc下发命令到第一个cn节点执行sql，因此登录xxx-dws-cn-cn-1-1节点，查看接收命执行情况，发现sql执行耗时较长，30s+

3、手动执行该sql然后查看线程等待视图，发现等待io

4、怀疑是脏页率过高导致执行的比较慢，发现系统表脏页率很高

5、给出查询各类资源的用户列表及权限的sql，后面协调时间做系统表脏页清理vacuum full

手动提供各个权限查询的sql语句：
SELECT  case c.relkind when 'r' then 'table' when 'v' then 'view' when 'S' then 'sequence' end as type,
            nsp.nspname, c.relname AS name, c.relacl AS acl FROM pg_class c LEFT JOIN pg_namespace nsp ON c.relnamespace = nsp.oid  
            WHERE c.relacl is not null and c.relkind IN ('r') and c.relacl::varchar like '%%'
        
SELECT 'database' as type, datname AS name, datacl AS acl FROM pg_database WHERE datacl is not null and datacl::varchar like '%%'

SELECT 'function' as type, 
             nsp.nspname, proname||'('||pg_get_function_identity_arguments(p.oid)||')' AS name, p.proacl AS acl
             FROM pg_proc p LEFT JOIN pg_namespace nsp ON p.pronamespace = nsp.oid WHERE p.proacl is not null and p.proacl::varchar like '%%'
             
SELECT 'schema' as type, nspname AS name, 
            nspacl AS acl FROM pg_namespace WHERE nspacl is not null and nspacl::varchar like '%%'

select * from pg_roles  where 
  
revoke语法参考；https://support.huaweicloud.com/sqlreference-910-dws/dws_06_0253.html
权限说明文档：https://support.huaweicloud.com/devg-910-dws/dws_04_0578.html