-- timestamptz check
CREATE TABLE timestamptztmp (a timestamptz);
\copy timestamptztmp from 'data/timestamptz.data'
SET enable_seqscan=on;
SELECT count(*) FROM timestamptztmp WHERE a <  '2018-12-18 10:59:54 GMT+3';
 count 
-------
   391
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <= '2018-12-18 10:59:54 GMT+3';
 count 
-------
   392
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a  = '2018-12-18 10:59:54 GMT+3';
 count 
-------
     1
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >= '2018-12-18 10:59:54 GMT+3';
 count 
-------
   158
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >  '2018-12-18 10:59:54 GMT+3';
 count 
-------
   157
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <  '2018-12-18 10:59:54 GMT+2';
 count 
-------
   391
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <= '2018-12-18 10:59:54 GMT+2';
 count 
-------
   391
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a  = '2018-12-18 10:59:54 GMT+2';
 count 
-------
     0
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >= '2018-12-18 10:59:54 GMT+2';
 count 
-------
   158
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >  '2018-12-18 10:59:54 GMT+2';
 count 
-------
   158
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <  '2018-12-18 10:59:54 GMT+4';
 count 
-------
   392
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <= '2018-12-18 10:59:54 GMT+4';
 count 
-------
   392
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a  = '2018-12-18 10:59:54 GMT+4';
 count 
-------
     0
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >= '2018-12-18 10:59:54 GMT+4';
 count 
-------
   157
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >  '2018-12-18 10:59:54 GMT+4';
 count 
-------
   157
(1 row)

SELECT a, a <-> '2018-12-18 10:59:54 GMT+2' FROM timestamptztmp ORDER BY a <-> '2018-12-18 10:59:54 GMT+2' LIMIT 3;
              a               |             ?column?              
------------------------------+-----------------------------------
 Tue Dec 18 05:59:54 2018 PST | @ 1 hour
 Thu Jan 10 03:01:34 2019 PST | @ 22 days 22 hours 1 min 40 secs
 Thu Jan 24 12:28:12 2019 PST | @ 37 days 7 hours 28 mins 18 secs
(3 rows)

CREATE INDEX timestamptzidx ON timestamptztmp USING gist ( a );
SET enable_seqscan=off;
SELECT count(*) FROM timestamptztmp WHERE a <  '2018-12-18 10:59:54 GMT+3'::timestamptz;
 count 
-------
   391
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <= '2018-12-18 10:59:54 GMT+3'::timestamptz;
 count 
-------
   392
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a  = '2018-12-18 10:59:54 GMT+3'::timestamptz;
 count 
-------
     1
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >= '2018-12-18 10:59:54 GMT+3'::timestamptz;
 count 
-------
   158
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >  '2018-12-18 10:59:54 GMT+3'::timestamptz;
 count 
-------
   157
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <  '2018-12-18 10:59:54 GMT+2'::timestamptz;
 count 
-------
   391
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <= '2018-12-18 10:59:54 GMT+2'::timestamptz;
 count 
-------
   391
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a  = '2018-12-18 10:59:54 GMT+2'::timestamptz;
 count 
-------
     0
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >= '2018-12-18 10:59:54 GMT+2'::timestamptz;
 count 
-------
   158
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >  '2018-12-18 10:59:54 GMT+2'::timestamptz;
 count 
-------
   158
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <  '2018-12-18 10:59:54 GMT+4'::timestamptz;
 count 
-------
   392
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a <= '2018-12-18 10:59:54 GMT+4'::timestamptz;
 count 
-------
   392
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a  = '2018-12-18 10:59:54 GMT+4'::timestamptz;
 count 
-------
     0
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >= '2018-12-18 10:59:54 GMT+4'::timestamptz;
 count 
-------
   157
(1 row)

SELECT count(*) FROM timestamptztmp WHERE a >  '2018-12-18 10:59:54 GMT+4'::timestamptz;
 count 
-------
   157
(1 row)

EXPLAIN (COSTS OFF)
SELECT a, a <-> '2018-12-18 10:59:54 GMT+2' FROM timestamptztmp ORDER BY a <-> '2018-12-18 10:59:54 GMT+2' LIMIT 3;
                                     QUERY PLAN                                     
------------------------------------------------------------------------------------
 Limit
   ->  Index Only Scan using timestamptzidx on timestamptztmp
         Order By: (a <-> 'Tue Dec 18 04:59:54 2018 PST'::timestamp with time zone)
(3 rows)

SELECT a, a <-> '2018-12-18 10:59:54 GMT+2' FROM timestamptztmp ORDER BY a <-> '2018-12-18 10:59:54 GMT+2' LIMIT 3;
              a               |             ?column?              
------------------------------+-----------------------------------
 Tue Dec 18 05:59:54 2018 PST | @ 1 hour
 Thu Jan 10 03:01:34 2019 PST | @ 22 days 22 hours 1 min 40 secs
 Thu Jan 24 12:28:12 2019 PST | @ 37 days 7 hours 28 mins 18 secs
(3 rows)