Oracle SQL Plan operation: HASH JOIN RIGHT SEMI

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
   id,
   tx
from
   tq84_A
where
   id in (select id_a from tq84_B);

select * from table(dbms_xplan.display(format=>'basic'));
--
-- ---------------------------------------
-- | Id  | Operation            | Name   |
-- ---------------------------------------
-- |   0 | SELECT STATEMENT     |        |
-- |   1 |  HASH JOIN RIGHT SEMI|        |
-- |   2 |   TABLE ACCESS FULL  | TQ84_B |
-- |   3 |   TABLE ACCESS FULL  | TQ84_A |
-- ---------------------------------------

drop table tq84_A;
drop table tq84_B;