Re: [BUGS] BUG #4810: Complex Contains, Bad Performace.

Sun, 17 May 2009 04:02:05 -0700

Tom Lane wrote: 
"Paul Mathews" <[email protected]> writes:
  
Despite the existence of the index, postgresql is determined to full table
scan when given.
  SELECT 
    postcode
  WHERE
    boundary @> point 'x,y';
    

polygon @> point isn't an indexable operator.  The indexable operators
for a gist index on polygon are

 <<(polygon,polygon)
 &<(polygon,polygon)
 &&(polygon,polygon)
 &>(polygon,polygon)
 >>(polygon,polygon)
 ~=(polygon,polygon)
 @>(polygon,polygon)
 <@(polygon,polygon)
 &<|(polygon,polygon)
 <<|(polygon,polygon)
 |>>(polygon,polygon)
 |&>(polygon,polygon)
 ~(polygon,polygon)
 @(polygon,polygon)

So it looks like you need to convert the point to a one-point polygon.

			regards, tom lane
WHERE
   g.boundary @> polygon(box(w.geocode,w.geocode));

Is there are more convenient, less ugly, way to convert a point to a polygon?

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