[OSM-dev] Distributed Data Store Follow-Up

Scott Shawcroft scott.shawcroft at gmail.com
Tue Mar 24 21:41:15 GMT 2009


Stefan de Konink wrote:
> Scott Shawcroft wrote:
>> Our update performance shouldn't be too different.  We simply send 
>> the update request to all the node machines.
>
> And your node machines do not cache their partition results? (Thus is 
> a scan always required?)
We don't do any caching ourselves but the underlying BerkeleyDB does.  
Therefore, we can update as we please.
>
>
>> By within do you mean a bounding box query?  Could you be more specific?
>
> For bbox you will have results for this:
>  ____
> |    |
> |  o-+--o
> |____|
>
> for within/touches you will have results for this:
>     ____
>    |    |
> o--+----+--o
>    |____|
>
> Now the above example is trivial to support the interesting case is 
> diagonal lines. This would allow perfect viewport calls.
We don't do within.  It is purely node based.  I suppose a spacial way 
index could be built to do within queries though.
>
>
> Stefan
>




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