[OSM-dev] Slow rendering

[Hartmut Holzgraefe]

On 04.05.21 13:50, Alex Chirigiu wrote:
> Although we have a pretty powerful server, we still can't nail the 
> config to make it as fast as it should be.
> We use a Ubuntu host with PostGIS and Mapnik on, and we want to render 
> Europe to Zoom 18/19 maybe. We managed to render Z15 completely, but it 
> took like 17 days...

that would be in the ballpark of about 50 tiles per second, right?

I have to confess that I don't really know how much tiles per second are 
realistic as I only use the postigs/mapnik combo to render full 
printable maps as a single non-tiled document ...

The first thing to look into though would probably whether the 
bottleneck is the the renderer processes/threads, or actually the
PostGIS databases.

Have you already tweaked the database to make good use of the RAM you 
have for example? Or are you still running default settings? At 256GB
you can "waste" quite a bit of memory to cache postgis data in RAM.
I don't remember the amount of data needed for an "all of Europe" import
anymore, but it might even be that this can be cached in RAM completely,
which would already drastically speed up things ...



-- 
hartmut