Cómo acelerar un st_intersects() consulta?

Question

Tengo un "gran" base de datos espaciales: 72 GB, 200 millones de documentos con la geometría (puntos) Tengo una idea índice sobre las geometrías

la base de datos:

CREATE TABLE resources
(
id bigint NOT NULL,
accuracy varchar(3),
owner varchar(100),
title varchar(500),
posted timestamp,   
nbtags int,
url text,
description text,
rawtags text,
tags text,
geom geometry NOT NULL,
CONSTRAINT resources_pkey PRIMARY KEY (id)
);
 INDEX resources_index_rep ON resources USING GIST (geom);

CREATE RULE resources_rule AS ON INSERT TO resources
WHERE EXISTS(SELECT 1 FROM resources
            WHERE id =NEW.id)
DO INSTEAD NOTHING;

Por supuesto que quiero a la consulta de esta base de datos. No obstante, es muy muy lento ... (Yo lo hice analiza y limpia)

por ejemplo, con zona de Francia:

EXPLAIN ANALYZE
SELECT count(*) 
FROM resources
WHERE st_intersects(st_geomfromtext('POLYGON((-5.134723 41.364166,-5.134723 51.09111,9.562222 51.09111,9.562222 41.364166,-5.134723 41.364166))',4326), geom)

QUERY PLAN
Aggregate  (cost=14411182.45..14411182.46 rows=1 width=0) (actual time=17368911.185..17368911.186 rows=1 loops=1)
 ->  Bitmap Heap Scan on resources  (cost=890493.27..14391392.83 rows=7915848 width=0) (actual time=2627029.235..17357552.440 rows=21381758 loops=1)
    Recheck Cond: ('0103000020E6100000010000000500000077137CD3F48914C05628D2FD9CAE444077137CD3F48914C0562B137EA98B4940F52EDE8FDB1F2340562B137EA98B4940F52EDE8FDB1F23405628D2FD9CAE444077137CD3F48914C05628D2FD9CAE4440'::geometry && geom)
    Filter: _st_intersects('0103000020E6100000010000000500000077137CD3F48914C05628D2FD9CAE444077137CD3F48914C0562B137EA98B4940F52EDE8FDB1F2340562B137EA98B4940F52EDE8FDB1F23405628D2FD9CAE444077137CD3F48914C05628D2FD9CAE4440'::geometry, geom)
    ->  Bitmap Index Scan on resources_index_rep  (cost=0.00..888514.31 rows=23747545 width=0) (actual time=2626090.609..2626090.609 rows=21381788 loops=1)
          Index Cond: ('0103000020E6100000010000000500000077137CD3F48914C05628D2FD9CAE444077137CD3F48914C0562B137EA98B4940F52EDE8FDB1F2340562B137EA98B4940F52EDE8FDB1F23405628D2FD9CAE444077137CD3F48914C05628D2FD9CAE4440'::geometry && geom)
Total runtime: 17368946.473 ms
7 row(s)

le tomó casi 5 horas.

y con Suiza:

EXPLAIN ANALYZE
SELECT count(*) 
FROM resources
WHERE st_intersects(st_geomfromtext('POLYGON((5.96611 45.829437,5.96611 47.806938,10.488913 47.806938,10.488913 45.829437,5.96611 45.829437))',4326), geom)

QUERY PLAN
Aggregate  (cost=5623425.68..5623425.69 rows=1 width=0) (actual time=6798842.064..6798842.064 rows=1 loops=1)
->  Bitmap Heap Scan on resources  (cost=88982.29..5621452.65 rows=789212 width=0) (actual time=783383.496..6797250.482 rows=2539057 loops=1)
    Recheck Cond: ('0103000020E61000000100000005000000AF5A99F04BDD1740D28BDAFD2AEA4640AF5A99F04BDD174028F38FBE49E74740B22D03CE52FA244028F38FBE49E74740B22D03CE52FA2440D28BDAFD2AEA4640AF5A99F04BDD1740D28BDAFD2AEA4640'::geometry && geom)
    Filter: _st_intersects('0103000020E61000000100000005000000AF5A99F04BDD1740D28BDAFD2AEA4640AF5A99F04BDD174028F38FBE49E74740B22D03CE52FA244028F38FBE49E74740B22D03CE52FA2440D28BDAFD2AEA4640AF5A99F04BDD1740D28BDAFD2AEA4640'::geometry, geom)
    ->  Bitmap Index Scan on resources_index_rep  (cost=0.00..88784.99 rows=2367636 width=0) (actual time=782664.847..782664.847 rows=2539063 loops=1)
          Index Cond: ('0103000020E61000000100000005000000AF5A99F04BDD1740D28BDAFD2AEA4640AF5A99F04BDD174028F38FBE49E74740B22D03CE52FA244028F38FBE49E74740B22D03CE52FA2440D28BDAFD2AEA4640AF5A99F04BDD1740D28BDAFD2AEA4640'::geometry && geom)
Total runtime: 6798852.955 ms
7 row(s)

le tomó casi 2 horas.

Estoy buscando la manera de mejorar el rendimiento?

Acerca de nuestro servidor:

- CPU: 4
- RAM: 16 GB
- OS: Ubuntu 12.04 LTS 64bit

Answer 1

Es un poco viejo, pero tal vez usted podría tratar su consulta con ST_DWithin lugar ? Ver este hilo.

Answer 2

No tiene demasiada experiencia en db rendimiento mejora. Pero me parece que esto podría ser útil.