mirror of
https://github.com/postgres/postgres.git
synced 2025-11-03 09:13:20 +03:00
8436489c81
This extends GiST's support for nearest-neighbor searches to many of the standard data types. Teodor Sigaev
92 lines
1.8 KiB
Plaintext
92 lines
1.8 KiB
Plaintext
-- float8 check
|
|
CREATE TABLE float8tmp (a float8);
|
|
\copy float8tmp from 'data/float8.data'
|
|
SET enable_seqscan=on;
|
|
SELECT count(*) FROM float8tmp WHERE a < -1890.0;
|
|
count
|
|
-------
|
|
237
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a <= -1890.0;
|
|
count
|
|
-------
|
|
238
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a = -1890.0;
|
|
count
|
|
-------
|
|
1
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a >= -1890.0;
|
|
count
|
|
-------
|
|
307
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a > -1890.0;
|
|
count
|
|
-------
|
|
306
|
|
(1 row)
|
|
|
|
SELECT a, a <-> '-1890.0' FROM float8tmp ORDER BY a <-> '-1890.0' LIMIT 3;
|
|
a | ?column?
|
|
--------------+------------
|
|
-1890 | 0
|
|
-2003.634512 | 113.634512
|
|
-1769.73634 | 120.26366
|
|
(3 rows)
|
|
|
|
CREATE INDEX float8idx ON float8tmp USING gist ( a );
|
|
SET enable_seqscan=off;
|
|
SELECT count(*) FROM float8tmp WHERE a < -1890.0::float8;
|
|
count
|
|
-------
|
|
237
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a <= -1890.0::float8;
|
|
count
|
|
-------
|
|
238
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a = -1890.0::float8;
|
|
count
|
|
-------
|
|
1
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a >= -1890.0::float8;
|
|
count
|
|
-------
|
|
307
|
|
(1 row)
|
|
|
|
SELECT count(*) FROM float8tmp WHERE a > -1890.0::float8;
|
|
count
|
|
-------
|
|
306
|
|
(1 row)
|
|
|
|
EXPLAIN (COSTS OFF)
|
|
SELECT a, a <-> '-1890.0' FROM float8tmp ORDER BY a <-> '-1890.0' LIMIT 3;
|
|
QUERY PLAN
|
|
-----------------------------------------------------
|
|
Limit
|
|
-> Index Scan using float8idx on float8tmp
|
|
Order By: (a <-> (-1890)::double precision)
|
|
(3 rows)
|
|
|
|
SELECT a, a <-> '-1890.0' FROM float8tmp ORDER BY a <-> '-1890.0' LIMIT 3;
|
|
a | ?column?
|
|
--------------+------------
|
|
-1890 | 0
|
|
-2003.634512 | 113.634512
|
|
-1769.73634 | 120.26366
|
|
(3 rows)
|
|
|