[OSM-dev] [OSM-talk] The future of Potlatch

Richard Fairhurst richard at systemeD.net
Fri May 2 18:00:34 BST 2008

bvh wrote:

> On Fri, May 02, 2008 at 03:37:57PM +0100, Richard Fairhurst wrote:
>> The other one is that it would be good if the getway call, in
> Just curious : what does this call actually do in fact?

Just gets a way and its tags, and all its nodes and their tags.


It's pretty similar to /api/0.5/way/<id>/full, it just predates it  
(and as Dave says it reprojects, largely for historical reasons).

The performance issue is with Way.find(wayid). This is several times  
slower than the equivalent SQL:

     SELECT latitude*0.0000001 AS latitude,longitude*0.0000001 AS  
       FROM current_way_nodes,current_nodes
      WHERE current_way_nodes.id=#{id}
        AND current_way_nodes.node_id=current_nodes.id

...I guess because it's creating Rails objects for all the nodes  
along the way, or something. Because Potlatch calls this for every  
single way, there's a pretty big performance hit.


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