Oracle: Unnested Subqueries using the FILTER plan operator

create table tq84_A (id   number, tx varchar2(3));
create table tq84_B (id_a number);

insert into tq84_A select level*37, 'X' from dual connect by level < 1000;
insert into tq84_B select level+91      from dual connect by level <  600;

begin
   dbms_stats.gather_table_stats(user, 'tq84_A');
   dbms_stats.gather_table_stats(user, 'tq84_B');
end;
/

explain plan for
select /*+ no_unnest(@subquery) */
   id,
   tx
from
   tq84_A
where
   id in (select /*+ qb_name(subquery) */ id_a from tq84_B);
select * from table(dbms_xplan.display(format=>'basic'));
--
-- -------------------------------------
-- | Id  | Operation          | Name   |
-- -------------------------------------
-- |   0 | SELECT STATEMENT   |        |
-- |*  1 |  FILTER            |        |
-- |   2 |   TABLE ACCESS FULL| TQ84_A |
-- |*  3 |   TABLE ACCESS FULL| TQ84_B |
-- -------------------------------------
--
-- Predicate Information (identified by operation id):
-- ---------------------------------------------------
--  
--    1 - filter( EXISTS (SELECT /*+ NO_UNNEST QB_NAME ("SUBQUERY") */ 0 
--               FROM "TQ84_B" "TQ84_B" WHERE "ID_A"=:B1))
--    3 - filter("ID_A"=:B1)


drop table tq84_A;
drop table tq84_B;