| From: | Håvard Wahl Kongsgård <haavard(dot)kongsgaard(at)gmail(dot)com> |
|---|---|
| To: | pgsql-general <pgsql-general(at)postgresql(dot)org> |
| Subject: | Performance on multiple OR conditions inside () |
| Date: | 2011-01-13 16:47:39 |
| Message-ID: | AANLkTingN4dwbSubov7_zbZ8+hxZTOsLGtci236yHbVV@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
Hi, I have a spatial query with multiple OR statements, for large tables
it's very slow. Is it possible to skip the spatial lookup on the other
conditions if first(previous) condition equal 1, and thereby increase the
performance?
SELECT vciia_main.sitrp,vciia_main.date_time from vciia_main,
south_vietnam72, roads, rails, houses, city where st_within(vciia_main.geom,
south_vietnam72.geom) and date_time is not null and
(st_dwithin(vciia_main.geom, roads.geom, 500) OR st_dwithin(vciia_main.geom,
rails.geom, 500) or st_dwithin(vciia_main.geom, city.geom, 800) or
st_dwithin(vciia_main.geom, houses.the_geom, 500))
--
Håvard Wahl Kongsgård
Peace Research Institute Oslo (PRIO)
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2011-01-13 17:20:20 | Re: Record with a field consisting of table rows |
| Previous Message | Pavel Stehule | 2011-01-13 16:44:06 | Re: Record with a field consisting of table rows |