Parallel_enable PL / SQL函数不会并行运行

Question

我有一个pl / sql parallel_enable流水线函数来写文件。如果单独运行，带并行提示的select语句可并行运行。但该功能并不是并行运行的。任何人都知道如何解决它？

select *
  from table(parallel_x(cursor (select /*+ parallel(c, 5) */
                      c.cid
                       from customers c)));

create or replace type x_t as object
(
  line_count number,
  session_id number
);

create or replace type x_tab as table of x_t;

function parallel_x(s in sys_refcursor) return x_tab
  pipelined
  parallel_enable(partition s by any) is

  session_id number;
  f          utl_file.file_type;
  line       varchar2(32767);
  line_count number := 0;

begin
  select sid into session_id from v$mystat where rownum = 1;

  file_name := 'file_' || session_id;

  f := utl_file.fopen(location     => 'directory',
                  filename     => file_name,
                  open_mode    => 'w',
                  max_linesize => 32767);

  loop
fetch s
  into line;

    utl_file.put_line(file => f, buffer => line);

line_count := line_count + 1;

exit when s%notfound;
  end loop;

utl_file.fclose(f);

 pipe row(x_t(line_count, session_id));

 return;
end;