[prev in list] [next in list] [prev in thread] [next in thread] 

List:       postgis-users
Subject:    Re: [postgis-users] help optimize distance calculation
From:       Ron M <rm_postgis () cheapcomplexdevices ! com>
Date:       2009-01-28 22:43:49
Message-ID: 4980DFA5.5080508 () cheapcomplexdevices ! com
[Download RAW message or body]

Sky wrote:
> A query over 400,000 points w/o dwithin took 972 seconds. A query over
> 400,000 points w/ dwithin(25000) took 111 seconds. Nice!
> 
> Sounds like I need to think about my scenario for a bit and figure out
> if I can strike a balance between dwithin tolerance and query
> execution time.

Seems you could make a loop starting with a very small dwithin tolerance and
doubling it in each iteration through a loop.  Hiding this in a stored
procedure would keep the queries clean.
_______________________________________________
postgis-users mailing list
postgis-users@postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users
[prev in list] [next in list] [prev in thread] [next in thread]