[Tilecache] Tilecache too slow

[christopher.schmidt at nokia.com]

On May 31, 2010, at 11:25 AM, ext Stefan Priess wrote:

> 
> Hello List, 
> 
> in loaded the planet.osm file into my db and want to prerender some tiles so i call: 
> 
> tilecache_seed.py osm 0 7 
> 
> my cifg: 
> 
> [osm] 
> type=Mapnik 
> mapfile=/opt/mapniktools/osm.xml 
> extension=png 
> spherical_mercator=true 
> metabuffer=256 
> metatile=yes 
> 
> Output: 
> 
> Cache miss: -20037508.34,-20037508.34,20037508.3384,20037508.3384, Tile: x: 0, y: 0, z: 0, time: 4.50857400894 
> Cache miss: -20037508.34,-20037508.34,-0.000799998641014,-0.000799998641014, Tile: x: 0, y: 0, z: 1, time: 2.24050211906 
> Cache miss: -20037508.34,-20037508.34,-10018754.1704,-10018754.1704, Tile: x: 0, y: 0, z: 2, time: 47.7445428371 
> Cache miss: -20037508.34,-20037508.34,-15028131.2552,-15028131.2552, Tile: x: 0, y: 0, z: 3, time: 33.1307868958 
> Cache miss: 5009377.084,-20037508.34,10018754.1688,-15028131.2552, Tile: x: 5, y: 0, z: 3, time: 23.2806358337 
> Cache miss: -20037508.34,5009377.084,-15028131.2552,10018754.1688, Tile: x: 0, y: 5, z: 3, time: 27.7289340496 
> Cache miss: 5009377.084,5009377.084,10018754.1688,10018754.1688, Tile: x: 5, y: 5, z: 3, time: 21.4363980293 
> Cache miss: -20037508.34,-20037508.34,-17532819.7976,-17532819.7976, Tile: x: 0, y: 0, z: 4, time: 2.18496513367 
> Cache miss: -7514065.628,-20037508.34,-5009377.0856,-17532819.7976, Tile: x: 5, y: 0, z: 4, time: 1.23492002487 
> Cache miss: 5009377.084,-20037508.34,7514065.6264,-17532819.7976, Tile: x: 10, y: 0, z: 4, time: 0.98893404007 
> Cache miss: 17532819.796,-20037508.34,20037508.3384,-17532819.7976, Tile: x: 15, y: 0, z: 4, time: 0.568192005157 
> Cache miss: -20037508.34,-7514065.628,-17532819.7976,-5009377.0856, Tile: x: 0, y: 5, z: 4, time: 23.5294082165 
> 
> This is too slow! 8GB Mem and 2x CPU with 4x Cores each 2,66GHz should have enough power. 
> I use Tilecache 2.10 with the Patch to avoid the zero data layer bug. 

1. TileCache does not do any rendering of any data. All of the rendering is done by your data source (in this case, Mapnik).
2. TileCache's seeding application is single threaded. Multiple CPUs will not help you pre-cache faster.
3. You are taking gigabytes of data and turning them into images. I don't know exactly what you're expecting, but none of these times seem out of line to me. 

If "TileCache is too slow", I would note that you will likely see the exactly same performance using Mapnik without TileCache. If this is too slow for you, you will likely need to write your own renderer. Good luck.

Regards,
-- 
Christopher Schmidt
Nokia