[Graphhopper] start and final routing point

[Peter K]

Hey Johannes,

the preparation of the graph is quite memory and time intensive, yes.
And for enabled turn restrictions also GraphHopper will probably need
more RAM.

Regarding running only the OSRM service itself: I think if you only had
5GB and the program needs 4GB, I think 1GB could be too few for the
system itself (and your local services). But the crash could be a bug
which you should report.

For GraphHopper you could try even with less RAM if you load the graph
via memory mapped data access (osmreader.dataaccess=mmap), but this will
slow down the query response time. Sometimes so bad that it is not
worth, only for memory restricted systems like Android/RasperryPi or
probably with SSD discs.

Another trick could be to use the chPrepare.createAStar() method to
boost the query time a bit, but only if you accept suboptimal paths.
(precision vs. speed depends on the approximationFactor in AStar)

Regards,
Peter.


> Hello Peter,
>
> my server is an old HP one with 5B RAM DualCore. I tried to get OSRM
> running with the germany osm file from geofabrik.de
> <http://geofabrik.de>. But finally it failed. I created the routing
> index files on an amazon instance, which needed max between 10 and 11
> GB RAM. The osrm-routed program just needs 3,9 GB RAM, so i tried to
> run it on my old hardware. Normally it should be enough, but the start
> process was killed with an alloc error. The swap partition was not
> used or ignored. Very strange.
>
> So i tried the graphhopper. Indexing the same extract file needs
> something between 1 and 2 GB Ram, during runtime just 1GB, so it
> fullfilled my requirements. One recordset could be calculated in 0,033
> seconds, while parallelisation reduces the runtime about 1/n.
>
> Greeting Johannes
>
>
> _______________________________________________
> GraphHopper mailing list
> GraphHopper at openstreetmap.org
> http://lists.openstreetmap.org/listinfo/graphhopper


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