Oracle SQL Plan operation: HASH JOIN ANTI NA

create table tq84_A (id number not null);
create table tq84_B (id number     null);
 
explain plan for
select * from tq84_A
where
   id not in (select id from tq84_B);
  
select * from table(dbms_xplan.display(format=>'basic'));  
-- 
-- -------------------------------------
-- | Id  | Operation          | Name   |
-- -------------------------------------
-- |   0 | SELECT STATEMENT   |        |
-- |   1 |  HASH JOIN ANTI NA |        |
-- |   2 |   TABLE ACCESS FULL| TQ84_A |
-- |   3 |   TABLE ACCESS FULL| TQ84_B |
-- -------------------------------------