[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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