-- int2 check
CREATE TABLE int2tmp (a int2);
\copy int2tmp from 'data/int2.data'
SET enable_seqscan=on;
SELECT count(*) FROM int2tmp WHERE a <  237;
 count 
-------
   297
(1 row)

SELECT count(*) FROM int2tmp WHERE a <= 237;
 count 
-------
   298
(1 row)

SELECT count(*) FROM int2tmp WHERE a  = 237;
 count 
-------
     1
(1 row)

SELECT count(*) FROM int2tmp WHERE a >= 237;
 count 
-------
   249
(1 row)

SELECT count(*) FROM int2tmp WHERE a >  237;
 count 
-------
   248
(1 row)

SELECT a, a <-> '237' FROM int2tmp ORDER BY a <-> '237' LIMIT 3;
  a  | ?column? 
-----+----------
 237 |        0
 232 |        5
 228 |        9
(3 rows)

SET client_min_messages = DEBUG1;
CREATE INDEX int2idx ON int2tmp USING gist ( a );
DEBUG:  building index "int2idx" on table "int2tmp" serially
DEBUG:  using sorted GiST build
CREATE INDEX int2idx_b ON int2tmp USING gist ( a ) WITH (buffering=on);
DEBUG:  building index "int2idx_b" on table "int2tmp" serially
DROP INDEX int2idx_b;
RESET client_min_messages;
SET enable_seqscan=off;
SELECT count(*) FROM int2tmp WHERE a <  237::int2;
 count 
-------
   297
(1 row)

SELECT count(*) FROM int2tmp WHERE a <= 237::int2;
 count 
-------
   298
(1 row)

SELECT count(*) FROM int2tmp WHERE a  = 237::int2;
 count 
-------
     1
(1 row)

SELECT count(*) FROM int2tmp WHERE a >= 237::int2;
 count 
-------
   249
(1 row)

SELECT count(*) FROM int2tmp WHERE a >  237::int2;
 count 
-------
   248
(1 row)

EXPLAIN (COSTS OFF)
SELECT a, a <-> '237' FROM int2tmp ORDER BY a <-> '237' LIMIT 3;
                   QUERY PLAN                   
------------------------------------------------
 Limit
   ->  Index Only Scan using int2idx on int2tmp
         Order By: (a <-> '237'::smallint)
(3 rows)

SELECT a, a <-> '237' FROM int2tmp ORDER BY a <-> '237' LIMIT 3;
  a  | ?column? 
-----+----------
 237 |        0
 232 |        5
 228 |        9
(3 rows)