[pgrouting-users] pgrouting speed

[Daniel Kastl]

2011/2/2 Charles Galpin <cgalpin at lhsw.com>

> I have seen this mentioned several times, but never got an idea of what a
> very high ID is? What's very high?
>

Best is when your ID's start with 1 and not with something like
100000000001.




>
> I have not tried this, but have considered using a smaller region initially
> and if a route is not found, jump to a bigger region and re-query, then
> perhaps fall back to an even bigger region before failing.  If 90% of your
> routing will fit into the first region size then in general you will get
> much faster routing, and in the cases it fails, only slightly slower.
>
> charles
>
> On Feb 2, 2011, at 3:36 AM, Daniel Kastl wrote:
>
> Hi Emre,
>
> How large is your network?
> I think you could do it faster, but it depends also on your hardware and
> you might also be able to make some changes in the postgresql configuration.
> Ride the city for example is using pgRouting and the size of the cities
> should be comparable to Istanbul:
> http://www.ridethecity.com/
>
> <http://www.ridethecity.com/>To improve speed you can check:
>
>    - Indices for attributes used in your query
>    - ID numbering (very high ID's make it slow)
>    - complicated cost calculation and joins between tables. If you have
>    this, maybe you could pre-calculate some costs.
>
> In general as less network data you load with your select as faster it is.
>
> Daniel
>
>
>
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>


-- 
Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
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