[postgis-users] Greetings, and road data questions

[Paul Ramsey]

Andy Turk wrote:

> One thing to explore is the use of multi-key indexes. I.e., you could
> have a single index that uses both a geometry field and a CFCC field. In
> my experience, this wasn't any quicker than using a straight geometry
> index followed by a sequential filtering of the matching rows to look at
> the feature code. My queries tend to be "small" and return usually less
> than 1000 rows based on the geometries alone.

Andy, could you re-elabourate on your multi-key experiment? In summary, 
to do multi-key indexes with PostGIS, you need for all your indexes to 
be GiST-based. The pgsql native btree cannot be multi-key'ed with a GiST 
index. So you have to use the contrib/btree_index package and then build 
a multi-key GiST-only index. At the end of the day, did this work?

-- 
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      | Paul Ramsey
      | Refractions Research
      | Email: pramsey at refractions.net
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