Connected to Oracle Database 11g Release 11.2.0.4.0 
Connected as supermag@//192.168.1.201/DBOFFICE

SQL> set serveroutput on;
SQL> 
SQL> declare
  2    tmp varchar2(100);
  3  begin
  4      for c in (select 'select '||level||' lvl from dual@DBNOHT0'||level query from dual connect by level < 10) loop
  5        dbms_output.put_line(c.query);
  6        execute immediate c.query into tmp;
  7        dbms_output.put_line(' tmp: '||tmp);
  8        commit;
  9      end loop;
 10  exception
 11     when others then
 12     dbms_output.put_line(sqlerrm);
 13     rollback;
 14  end;
 15  /
 
select 1 lvl from dual@DBNOHT01
 tmp: 1
select 2 lvl from dual@DBNOHT02
 tmp: 2
select 3 lvl from dual@DBNOHT03
 tmp: 3
select 4 lvl from dual@DBNOHT04
 tmp: 4
select 5 lvl from dual@DBNOHT05
 tmp: 5
select 6 lvl from dual@DBNOHT06
 tmp: 6
select 7 lvl from dual@DBNOHT07
 tmp: 7
select 8 lvl from dual@DBNOHT08
 tmp: 8
select 9 lvl from dual@DBNOHT09
 tmp: 9

PL/SQL procedure successfully completed


SQL> 
SQL> declare
  2    tmp varchar2(100);
  3  begin
  4      for c in (select 'select '||level||' lvl from dual@DBNOHT0'||level query from dual connect by level < 10) loop
  5        dbms_output.put_line(c.query);
  6        execute immediate c.query into tmp;
  7        dbms_output.put_line(' tmp: '||tmp);
  8        --commit;
  9      end loop;
 10  exception
 11     when others then
 12     dbms_output.put_line(sqlerrm);
 13     rollback;
 14  end;
 15  /
select 1 lvl from dual@DBNOHT01
 tmp: 1
select 2 lvl from dual@DBNOHT02
 tmp: 2
select 3 lvl from dual@DBNOHT03
 tmp: 3
select 4 lvl from dual@DBNOHT04
 tmp: 4
select 5 lvl from dual@DBNOHT05
ORA-02020: используется слишком много каналов связи БД

PL/SQL procedure successfully completed


SQL> 
SQL> declare
  2    tmp number;
  3  begin
  4    select count(1) into tmp
  5      from (
  6              select 1 lvl from dual@DBNOHT01 union all
  7              select 1 lvl from dual@DBNOHT02 union all
  8              select 1 lvl from dual@DBNOHT03 union all
  9              select 1 lvl from dual@DBNOHT04 union all
 10              select 1 lvl from dual@DBNOHT05
 11           );
 12  exception
 13     when others then
 14     dbms_output.put_line(sqlerrm);
 15     rollback;
 16  end;
 17  /
declare
  tmp number;
begin
  select count(1) into tmp
    from (
            select 1 lvl from dual@DBNOHT01 union all
            select 1 lvl from dual@DBNOHT02 union all
            select 1 lvl from dual@DBNOHT03 union all
            select 1 lvl from dual@DBNOHT04 union all
            select 1 lvl from dual@DBNOHT05
         );
exception
   when others then
   dbms_output.put_line(sqlerrm);
   rollback;
end;

ORA-04052: ошибка во время поиска удаленного объекта SUPERMAG.DUAL@DBNOHT05
ORA-00604: ошибка на рекурсивном SQL-уровне 1
ORA-02020: используется слишком много каналов связи БД

SQL>