Paul Scott schreef:
Did anyone actually get this mail?
it came through :-)
More concrete example? What would you like to see?
the column spec. what kind of geomtery column is it? and
are you using it as a primary key? or some else ... if so what kind
of stuff are you storing in there? also in what way are you
using it that gives you such a speed boost with queries?
I read the mysql docs, I understand the principles but I'm having
a hard time figuring out how to apply in practice in terms of
making use of the performance gains you mentione ... specifically
in a web environment where heavy queries are often along the lines
of paginated data combined with user defined filters (e.g. a product
list sorted by price, etc and filter on type/category/keyword/etc)
sorry if I'm sounding like a idiot :-)
I suspect that some of my mail is getting dropped :(
--Paul
On Fri, 2008-02-01 at 06:33 +0200, Paul Scott wrote:
On Fri, 2008-02-01 at 03:40 +0100, Jochem Maas wrote:
I for one would really like to see a concrete example of this kind of
use of geometry columns and spacial indexes as an alternative to the stand
integer based primary keys.
On one of my local postGIS tables:
CREATE INDEX k1
ON kanagawa
USING gist
(the_geom);
A gist index is a GEOS based spatial index. You will need GEOS to create
one.
When loading spatial data, your geometry column looks like so:
01050000000100000001020000000C00000011ECE564CF7561404A8999CCDABC4140E5C0981ACE75614012901CD641BD4140603C8386BE756140E525611B40BD41405BF216D3BD756140151DC9E53FBD414054DC1A4DBD756140760B997A3FBD414012219BD1BC756140D20823E33EBD41407AB2884EBC7561400F2110243EBD41404571B4D0BB756140CC0C6A213DBD4140F707192ABB7561405DF2A1803CBD4140F0F11CA4BA756140C3D1B7413CBD4140E89CB2ADB97561406F046D233CBD414017D4B7CCA97561406D47AD7F39BD4140
Which is WKB (Well Known Binary) data or WKT (Well Known Text) data. The
gist index simply indexes this as opposed to the regular gid (which you
still use btree indexes on anyways)
--Paul
All Email originating from UWC is covered by disclaimer
http://www.uwc.ac.za/portal/public/portal_services/disclaimer.htm
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
------------------------------------------------------------------------
All Email originating from UWC is covered by disclaimer
http://www.uwc.ac.za/portal/public/portal_services/disclaimer.htm
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
