CREATE TABLE keyset_demo (a INTEGER, ts date, id integer primary key);


INSERT INTO keyset_demo
SELECT mod(level, 1000), CURRENT_TIMESTAMP - INTERVAL '1' SECOND * DBMS_RANDOM.normal()*86400, level
  FROM DUAL
CONNECT BY level < 65536 * 16;

CREATE INDEX keyset_demo_ids ON keyset_demo (a, ts, id);

ALTER SESSION SET statistics_level = ALL;
SELECT * FROM (
SELECT keyset_demo.*
  FROM keyset_demo
 WHERE a = 17 AND ts = '2015-12-12 08:41:05' and id > 547
    OR a = 17 AND ts > '2015-12-12 08:41:05' 
    OR a > 17 
ORDER BY a, ts, id
) t
WHERE rownum <= 5
;

SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(null, null, 'LAST ALLSTATS'));

SELECT * FROM (
SELECT keyset_demo.*
  FROM keyset_demo
 WHERE a >= 17
   AND NOT (a = 17 AND ts <='2015-12-12 08:41:05')
   AND NOT (a = 17 AND ts = '2015-12-12 08:41:05' AND id <= 547)
ORDER BY a, ts, id
) t
WHERE rownum <= 5
;
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(null, null, 'LAST ALLSTATS'));

SELECT * FROM (
SELECT keyset_demo.*, rownum rn
FROM keyset_demo
ORDER BY a, ts, id
) t
WHERE rn > 17833 AND rn <= 17838
;


SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(null, null, 'LAST ALLSTATS'));