[Routing] generalized routing format - pre-computation

[Sascha Silbe]

On Sat, Oct 18, 2008 at 03:59:11PM +0200, Lambertus wrote:

> Gosmore needs about 5 hours on a 3 GHz P4 to build a 4.8 GB db for 
> America which contains about 70% of all the OSM data.
Does gosmore check place=... areas to determine whether a way is inside 
a built-up area to adjust the speed accordingly? In that case I'll have 
to dig into the Gosmore source again to see how Nic got it this fast. :)

> A rebuild for the Netherlands took 15 minutes resulting a 224 MB db. 
> The time needed for a Gosmore db build process is therefore linear to 
> it's size.
The plain database import (without the area precalculation) seems to 
scale linearly up to a given point (where the size of the node location 
file exceeds RAM size), after that the penalty from having to fall back 
to disk is significant (as expected). In theory, it still scales 
linearly - just with a large constant factor (disk speed vs. RAM speed). 
;)

CU Sascha

-- 
http://sascha.silbe.org/
http://www.infra-silbe.de/
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