管道表函数 pipelined

 

drop table t1;
drop table t2

drop type t2_type;
drop type t2_tab_type ;

drop function parallel_pipelined ;

----------------------------------------------------------------------
create table t1 as select object_id id ,object_name text from all_objects ;

begin
  dbms_stats.set_table_stats(user,'T1',numrows => 10000000,numblks => 100000);
end;

create table t2 as select t1.*,0 session_id from t1 where 1=0 ;

create or replace type t2_type as object (
  id number,
  text varchar2(30),
  session_id number
);

create or replace type t2_tab_type
as table of t2_type;

create or replace function parallel_pipelined (l_cursor in sys_refcursor )
  return t2_tab_type
  pipelined
  parallel_enable ( partition  l_cursor by any )
is
  l_session_id number;
  l_rec        t1%rowtype;
begin
  select sid
  into l_session_id
  from v$mystat
  where rownum  = 1 ;

  loop
    fetch l_cursor into l_rec;
    exit when l_cursor%notfound;

    pipe row(t2_type(l_rec.id,l_rec.text,l_session_id));
  end loop;
  close l_cursor;
  return;
end;

alter session enable parallel dml;

truncate table t2 ;

insert /*+ append */
into t2 (id,text,session_id)
select * from table (parallel_pipelined
                    (cursor(select /*+ parallel(t1,2) */* from t1 )
      )) ;
commit;

select session_id ,count(*) from t2 group by session_id ;

 

                                                                                                                                from :oracle 9i&10g 编程艺术 深入数据库体系结构 page: 647