CREATE TABLE test_timestamp (
	i timestamp
);
INSERT INTO test_timestamp VALUES
	( '2004-10-26 03:55:08' ),
	( '2004-10-26 04:55:08' ),
	( '2004-10-26 05:55:08' ),
	( '2004-10-26 08:55:08' ),
	( '2004-10-26 09:55:08' ),
	( '2004-10-26 10:55:08' )
;
SELECT i::timestamptz AS i INTO test_timestamptz FROM test_timestamp;
SELECT i <=> '2004-10-26 06:24:08', i FROM test_timestamp ORDER BY 1, 2 ASC;
 ?column? |            i             
----------+--------------------------
     1740 | Tue Oct 26 05:55:08 2004
     5340 | Tue Oct 26 04:55:08 2004
     8940 | Tue Oct 26 03:55:08 2004
     9060 | Tue Oct 26 08:55:08 2004
    12660 | Tue Oct 26 09:55:08 2004
    16260 | Tue Oct 26 10:55:08 2004
(6 rows)

SELECT i <=| '2004-10-26 06:24:08', i FROM test_timestamp ORDER BY 1, 2 ASC;
 ?column? |            i             
----------+--------------------------
     1740 | Tue Oct 26 05:55:08 2004
     5340 | Tue Oct 26 04:55:08 2004
     8940 | Tue Oct 26 03:55:08 2004
 Infinity | Tue Oct 26 08:55:08 2004
 Infinity | Tue Oct 26 09:55:08 2004
 Infinity | Tue Oct 26 10:55:08 2004
(6 rows)

SELECT i |=> '2004-10-26 06:24:08', i FROM test_timestamp ORDER BY 1, 2 ASC;
 ?column? |            i             
----------+--------------------------
     9060 | Tue Oct 26 08:55:08 2004
    12660 | Tue Oct 26 09:55:08 2004
    16260 | Tue Oct 26 10:55:08 2004
 Infinity | Tue Oct 26 03:55:08 2004
 Infinity | Tue Oct 26 04:55:08 2004
 Infinity | Tue Oct 26 05:55:08 2004
(6 rows)

CREATE INDEX idx_timestamp ON test_timestamp USING rum (i);
CREATE INDEX idx_timestamptz ON test_timestamptz USING rum (i);
set enable_seqscan=off;
explain (costs off)
SELECT * FROM test_timestamp WHERE i<'2004-10-26 08:55:08'::timestamp ORDER BY i;
                                    QUERY PLAN                                     
-----------------------------------------------------------------------------------
 Sort
   Sort Key: i
   ->  Index Scan using idx_timestamp on test_timestamp
         Index Cond: (i < 'Tue Oct 26 08:55:08 2004'::timestamp without time zone)
(4 rows)

SELECT * FROM test_timestamp WHERE i<'2004-10-26 08:55:08'::timestamp ORDER BY i;
            i             
--------------------------
 Tue Oct 26 03:55:08 2004
 Tue Oct 26 04:55:08 2004
 Tue Oct 26 05:55:08 2004
(3 rows)

explain (costs off)
SELECT * FROM test_timestamp WHERE i<='2004-10-26 08:55:08'::timestamp ORDER BY i;
                                     QUERY PLAN                                     
------------------------------------------------------------------------------------
 Sort
   Sort Key: i
   ->  Index Scan using idx_timestamp on test_timestamp
         Index Cond: (i <= 'Tue Oct 26 08:55:08 2004'::timestamp without time zone)
(4 rows)

SELECT * FROM test_timestamp WHERE i<='2004-10-26 08:55:08'::timestamp ORDER BY i;
            i             
--------------------------
 Tue Oct 26 03:55:08 2004
 Tue Oct 26 04:55:08 2004
 Tue Oct 26 05:55:08 2004
 Tue Oct 26 08:55:08 2004
(4 rows)

explain (costs off)
SELECT * FROM test_timestamp WHERE i='2004-10-26 08:55:08'::timestamp ORDER BY i;
                                 QUERY PLAN                                  
-----------------------------------------------------------------------------
 Index Scan using idx_timestamp on test_timestamp
   Index Cond: (i = 'Tue Oct 26 08:55:08 2004'::timestamp without time zone)
(2 rows)

SELECT * FROM test_timestamp WHERE i='2004-10-26 08:55:08'::timestamp ORDER BY i;
            i             
--------------------------
 Tue Oct 26 08:55:08 2004
(1 row)

explain (costs off)
SELECT * FROM test_timestamp WHERE i>='2004-10-26 08:55:08'::timestamp ORDER BY i;
                                     QUERY PLAN                                     
------------------------------------------------------------------------------------
 Sort
   Sort Key: i
   ->  Index Scan using idx_timestamp on test_timestamp
         Index Cond: (i >= 'Tue Oct 26 08:55:08 2004'::timestamp without time zone)
(4 rows)

SELECT * FROM test_timestamp WHERE i>='2004-10-26 08:55:08'::timestamp ORDER BY i;
            i             
--------------------------
 Tue Oct 26 08:55:08 2004
 Tue Oct 26 09:55:08 2004
 Tue Oct 26 10:55:08 2004
(3 rows)

explain (costs off)
SELECT * FROM test_timestamp WHERE i>'2004-10-26 08:55:08'::timestamp ORDER BY i;
                                    QUERY PLAN                                     
-----------------------------------------------------------------------------------
 Sort
   Sort Key: i
   ->  Index Scan using idx_timestamp on test_timestamp
         Index Cond: (i > 'Tue Oct 26 08:55:08 2004'::timestamp without time zone)
(4 rows)

SELECT * FROM test_timestamp WHERE i>'2004-10-26 08:55:08'::timestamp ORDER BY i;
            i             
--------------------------
 Tue Oct 26 09:55:08 2004
 Tue Oct 26 10:55:08 2004
(2 rows)

explain (costs off)
SELECT * FROM test_timestamptz WHERE i>'2004-10-26 08:55:08'::timestamptz ORDER BY i;
                                     QUERY PLAN                                     
------------------------------------------------------------------------------------
 Sort
   Sort Key: i
   ->  Index Scan using idx_timestamptz on test_timestamptz
         Index Cond: (i > 'Tue Oct 26 08:55:08 2004 PDT'::timestamp with time zone)
(4 rows)

SELECT * FROM test_timestamptz WHERE i>'2004-10-26 08:55:08'::timestamptz ORDER BY i;
              i               
------------------------------
 Tue Oct 26 09:55:08 2004 PDT
 Tue Oct 26 10:55:08 2004 PDT
(2 rows)