创建函数查询greenplum使用到某个数据表的所有视图

有些时候，我们需要查询哪些视图引用了某张数据表，在greenplumdb里面，可以创建如下的函数来查询，代码如下：

CREATE OR REPLACE FUNCTION public.get_views_used_by_table(text)
    RETURNS setof record  as 
$FBODY$
    select distinct vn.nspname || '.'||vc.relname as viewname  
    from pg_class c join pg_namespace n on n.oid=c.relnamespace
    left join pg_depend d on d.refobjid =c.oid 
    left join pg_rewrite r on r.oid =d.objid
    left join pg_class vc on r.ev_class =vc.oid
    left join pg_namespace vn on vc.relnamespace=vn.oid
    where  d.deptype='n' and
    d.classid =2618 and 
  r.rulename ='_RETURN' and
  vc.relkind='v' and 
  c.oid =$1::regclass ;
$FBODY$

LANGUAGE sql volatile;

使用如下：

testdb1=# select public.get_views_used_by_table('public.test9');
 get_views_used_by_table 
-------------------------
 (public.v_test9)
(1 row)

testdb1=# select * from public.get_views_used_by_table('public.test9') as A(viewname text);
    viewname    
----------------
 public.v_test9
(1 row)