[OSM-dev] Mapnik's speed rendering slow ?

Artem Pavlenko artem.mapnik at googlemail.com
Sat Nov 8 16:29:47 GMT 2008


Hi Sylvain,

You can improve rendering speed significantly by rendering one big  
'meta' tile and then chopping it
up into actual tiles. In my experience 8x8 (64) or even 16*16 (256)  
meta tiles make all process much faster.
Also, consider using mod_tile which is using the same approach and  
relatively easy to setup.

Best
Artem

On 8 Nov 2008, at 15:59, sylvain letuffe wrote:

> Hi there,
>
> I'have set up a tiles server based on mapnik that I plan to use (for  
> now) for
> France only.
> ( Very good wiki page explaining that)
> My setup is : debian etch 64/mapnik 0.5.1/postGIS/generate_tiles.py
> with a quite common machine : dual core 2.5GHZ / 2Go RAM
>
> After much fighting I finaly made it work, and I am happy on all  
> aspects, but
> speed.
>
> While the Mapnik at openstreetmap.org does the rendering (until  
> level 18 if I
> see it well) in something like around ~24 hours, I am currently  
> doing it for
> france (600Mo of osm data) until level 14 at a poor ~15 hours time
>
> Unless the server over there is a martian one clocked at 10^16 Hz, I  
> think I'm
> doing something wrong, but what ?
>
> I was searching on the wiki/doc at mapnik but didn't find tips for  
> that
>
> The only thing I changed in generate_tiles.py is :
> minZoom = 5
> maxZoom = 16
> bbox = (-4, 42.0,8,50.0)
> render_tiles(bbox, mapfile, tile_dir, minZoom, maxZoom)
>
> Symptoms to help :
> - The CPU is fed up at 100% ( load 1.00)
> - The memory is almost unused (5Mo for postgres !! 60Mo for  
> generate_tiles.py)
> - The disk is unused
> - A tile takes ~0.5s to be generated
> - Severall thousand of "Empty Tile" messages appears during the  
> process, while
> still taking ~0.5s
> Does this benchmark looks okay ?
>
> Thanks for help or URL
>
>
>
> -- 
> Sylvain Letuffe liste at letuffe.org
> qui suis-je : http://slyserv.dyndns.org
>
>
>
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