Connected to:
Oracle8i Release 8.1.7.4.0 - Production
JServer Release 8.1.7.4.0 - Production

SQL> CREATE TABLE iot_test
  2  (a NUMBER NOT NULL,
  3   b NUMBER      NOT NULL,
  4   CONSTRAINT iot_test_PK PRIMARY KEY (a)
  5  )
  6  ORGANIZATION INDEX;

Table created.

SQL> BEGIN
  2  
  3    FOR n IN 1..100000 LOOP
  4    
  5      INSERT INTO iot_test(a,b)
  6      VALUES (n , n +1);
  7      
  8    END LOOP;
  9    
 10    COMMIT;
 11    
 12  END;
 13  /

PL/SQL procedure successfully completed.

SQL> CREATE TABLE non_iot_test AS SELECT * FROM iot_test;

Table created.

SQL> ALTER TABLE non_iot_test ADD CONSTRAINT non_iot_test_pk PRIMARY KEY (a);

Table altered.

SQL> set autotrace traceonly explain
SQL> alter session set optimizer_goal=rule;

Session altered.

SQL> SELECT b FROM iot_test WHERE a=12;

Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=RULE (Cost=1 Card=1 Bytes=26)
   1    0   INDEX (UNIQUE SCAN) OF 'IOT_TEST_PK' (UNIQUE) (Cost=1 Card=1 Bytes=26)


SQL> SELECT b FROM non_iot_test WHERE a=12;

Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=RULE
   1    0   TABLE ACCESS (BY INDEX ROWID) OF 'NON_IOT_TEST'
   2    1     INDEX (UNIQUE SCAN) OF 'NON_IOT_TEST_PK' (UNIQUE)



SQL>