[OSM-dev] Unexistant wayed segments in planet?

Brett Henderson brett at bretth.com
Sun Sep 16 23:31:11 BST 2007


Tom Hughes wrote:
> Not as far as I know it won't...
>
> Well it could if you used the task that reads the history tables but
> that is (a) slower and (b) does not produce consistent results. Hence
> the new task that was added to use the current data tables. That task
> cannot produce a consistent snapshot however.
>
> Tom
>   
By non-consistent results do you mean that the old TIGER data is 
included?  If so I assumed this was a temporary problem that could be 
addressed if/when current database issues are resolved.  I'm sure there 
will be other minor discrepancies due to the lack of transactional 
database support across multiple db updates but these should be 
relatively few and easily corrected via the API.  The way history 
problem will go away nicely when API 0.5 is deployed, so that only 
leaves nodes.

As far as speed is concerned, it should be much faster.  Once a 
consistent snapshot is achieved from that point on you can use the 
changeset derivation task to only pull changes within a specific time 
interval.  This should drastically reduce the load on the primary 
database and perhaps even allow more frequent data extracts.

I added the current table reader to mirror the current planet.rb 
behaviour but long term I'm hoping that it won't be needed.

Cheers,
Brett





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