--Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit
DROP TABLE TST_1
/
CREATE TABLE TST_1 AS SELECT * FROM DBA_OBJECTS WHERE 1=2
/

BEGIN 

FOR I IN 1..400 LOOP
  INSERT INTO TST_1 SELECT * FROM DBA_OBJECTS;
END LOOP;
commit;
END;
/

CREATE INDEX INDX_TST_1_OBJID ON TST_1 (OBJECT_ID)
/
DROP TABLE TST_2
/
CREATE TABLE TST_2 AS SELECT * FROM DBA_OBJECTS WHERE 1=2
/

BEGIN
FOR I IN 1..300 LOOP
  INSERT INTO TST_2 SELECT * FROM DBA_OBJECTS;
END LOOP;
COMMIT;
END;
/



/*
SQL> @@ "load_test_data.sql"

Table dropped.


Table created.


PL/SQL procedure successfully completed.


Index created.


Table dropped.


Table created.


PL/SQL procedure successfully completed.

SQL>
*/

SELECT A.* FROM TST_1 A 
              LEFT OUTER JOIN TST_2 B
              ON (A.OBJECT_ID=B.OBJECT_ID);