[OSM-dev] [API] Suggestion: Baselines

[Stefan de Konink]

Chris Browet wrote:
> 
> 
> 2009/5/26 Stefan de Konink <stefan at konink.de <mailto:stefan at konink.de>>
> 
>     Chris Browet wrote:
> 
>            If you just want to materialise the entire database at a certain
>            interval, don't you think this will grow very fast?
> 
> 
>         I don't know. A baseline would only consist of a list of all
>         objects id with their associated version number at a certain
>         point in time, not the actual objects...
> 
> 
>     Think of a way X; it consist of n nodes. If you take the this way at
>     changeset Y, you would still have to find all nodes positions at
>     time(Y).
> 
> 
> Sure, but as we'd take a version snapshot of all objects anyway, the X 
> way will still be only say 8 bytes for the id and n (don't know the 
> definaition for versions, let's assume 4) bytes for the version. That is 
> 12 bytes per object * 360.000.000 is ~4.5Gb.
> 
> Assuming daily, one year rotating, online baselines, that makes 1.5 Tb, 
> i.e. 2 big disks (with overhead), i.e. 200€.
> 
> Not that expensive IMHO...

Then you want a materialised snapshot right? :) I don't think the edit 
database should be poluted by this. But it is an option to do what you want.


Stefan