set enable_seqscan=off;
CREATE TABLE test_interval (
	i interval
);
INSERT INTO test_interval VALUES
	( '03:55:08' ),
	( '04:55:08' ),
	( '05:55:08' ),
	( '08:55:08' ),
	( '09:55:08' ),
	( '10:55:08' )
;
CREATE INDEX idx_interval ON test_interval USING rum (i);
SELECT * FROM test_interval WHERE i<'08:55:08'::interval ORDER BY i;
            i             
--------------------------
 @ 3 hours 55 mins 8 secs
 @ 4 hours 55 mins 8 secs
 @ 5 hours 55 mins 8 secs
(3 rows)

SELECT * FROM test_interval WHERE i<='08:55:08'::interval ORDER BY i;
            i             
--------------------------
 @ 3 hours 55 mins 8 secs
 @ 4 hours 55 mins 8 secs
 @ 5 hours 55 mins 8 secs
 @ 8 hours 55 mins 8 secs
(4 rows)

SELECT * FROM test_interval WHERE i='08:55:08'::interval ORDER BY i;
            i             
--------------------------
 @ 8 hours 55 mins 8 secs
(1 row)

SELECT * FROM test_interval WHERE i>='08:55:08'::interval ORDER BY i;
             i             
---------------------------
 @ 8 hours 55 mins 8 secs
 @ 9 hours 55 mins 8 secs
 @ 10 hours 55 mins 8 secs
(3 rows)

SELECT * FROM test_interval WHERE i>'08:55:08'::interval ORDER BY i;
             i             
---------------------------
 @ 9 hours 55 mins 8 secs
 @ 10 hours 55 mins 8 secs
(2 rows)