-- генерация
CREATE TABLE test.test  (
	id serial PRIMARY KEY
	,x	numeric
	,y	numeric
	,z numeric)
;
INSERT INTO test.test (x,y,z) SELECT 100*random(),100*random(),100*random() FROM generate_series(1,300000);

--индексы
CREATE INDEX ON test.test
USING GIST (point(x,y),point(x,z),point(y,z));

CREATE INDEX ON test.test
(x);
CREATE INDEX ON test.test
(y);
CREATE INDEX ON test.test
(z);

--тесты
SELECT * FROM test.test WHERE
		x>= 15 AND X<20
 AND	y>= 15 AND y<20
 AND	z>= 15 AND z<20;
-----------------
Bitmap Heap Scan on test  (cost=1175.85..1322.50 rows=40 width=40) (actual rows=35 loops=1)
  Recheck Cond: ((y >= 15::numeric) AND (y < 20::numeric) AND (x >= 15::numeric) AND (x < 20::numeric) AND (z >= 15::numeric) AND (z < 20::numeric))
  Heap Blocks: exact=35
  Buffers: shared hit=35 read=183
  ->  BitmapAnd  (cost=1175.85..1175.85 rows=40 width=0) (actual rows=0 loops=1)
        Buffers: shared read=183
        ->  Bitmap Index Scan on test_y_idx  (cost=0.00..387.04 rows=15062 width=0) (actual rows=15135 loops=1)
              Index Cond: ((y >= 15::numeric) AND (y < 20::numeric))
              Buffers: shared read=61
        ->  Bitmap Index Scan on test_x_idx  (cost=0.00..387.60 rows=15118 width=0) (actual rows=15101 loops=1)
              Index Cond: ((x >= 15::numeric) AND (x < 20::numeric))
              Buffers: shared read=61
        ->  Bitmap Index Scan on test_z_idx  (cost=0.00..400.67 rows=15625 width=0) (actual rows=15272 loops=1)
              Index Cond: ((z >= 15::numeric) AND (z < 20::numeric))
              Buffers: shared read=61
Planning time: 0.236 ms
Execution time: 14.507 ms
-----------------------------

SELECT * FROM test.test WHERE
		POINT(x,Y) >>point(15,0)
AND		POINT(x,Y) <<point(20,0)
AND		POINT(x,Y) >^point(0,15)
AND		POINT(x,Y) <^point(0,20)

AND 
		POINT(x,z) >>point(15,0)
AND		POINT(x,z) <<point(20,0)
AND		POINT(x,z) >^point(0,15)
AND		POINT(x,z) <^point(0,20)
-------------------------------------
Index Scan using test_point_point1_point2_idx on test  (cost=0.34..8.38 rows=1 width=40) (actual rows=35 loops=1)
  Index Cond: ((point((x)::double precision, (y)::double precision) >> '(15,0)'::point) AND (point((x)::double precision, (y)::double precision) << '(20,0)'::point) AND (point((x)::double precision, (y)::double precision) >^ '(0,15)'::point) AND (point((x)::double precision, (y)::double precision) <^ '(0,20)'::point) AND (point((x)::double precision, (z)::double precision) >> '(15,0)'::point) AND (point((x)::double precision, (z)::double precision) << '(20,0)'::point) AND (point((x)::double precision, (z)::double precision) >^ '(0,15)'::point) AND (point((x)::double precision, (z)::double precision) <^ '(0,20)'::point))
  Buffers: shared hit=65
Planning time: 0.261 ms
Execution time: 0.864 ms
-------------------------------------