[OSM-dev] [OSM-talk] Oh dear - planet has duplicate id's

Richard Fairhurst richard at systemeD.net
Thu May 31 14:51:55 BST 2007


David Earl wrote:

> (d) or maybe there is a timing problem whereby two clients trying to  
>  add segments at the same time get allocated the same id. Again,   
> major integrity problem.

AIUI:

New ids should only be generated one way - by an INSERT into the  
current_segments table. This has an auto_increment on the 'id' column.  
So according to the database, a duplicate id shouldn't be possible.

Don't forget that, as long as all database operations on the  
ways/segments/nodes tables (_not_  
current_ways/current_segments/current_nodes) are restricted to INSERT,  
i.e. no DELETE or UPDATE, then we have full versioning and history. I  
believe this is still the case. Therefore any client or API bugs can  
be reversed, even if it's a bit painful!

cheers
Richard





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