[OSM-dev] Data checks?

Martijn van Oosterhout kleptog at gmail.com
Mon Feb 18 08:31:36 GMT 2008


On Feb 15, 2008 11:38 PM, Tom Enterline (OSM) <osm at enterline.us> wrote:
> What has already been done on data checks, and is anyone else working on
> it? What would be some good ideas to start with, and goals to work toward?

A bit late to the party, but I have some comments:
The comment about the planet dump not being a consistant snapshot is
correct. Better is to take a planet dump and apply the next daily
diff. That gives you a snapshot the *is* consistant.

Secondly, prevention is better than cure. It would be worthwhile going
over all the code that accesses the server database and determine if
it is "safe". The lack of transactions makes it more difficult, but
the idea is that prior to deleting a node you check that it's not
used, after locking it. And more importantly, *after* you've deleted
it, check again.

Alternatively, when adding/updating a way, lock the component nodes
prior to doing the update so they can't get deleted in the meantime.

There are many methods and complete books written on the topic. Choose
whichever you like best, but it's certainly a problem that needs to be
solved.

Have a nice day,
-- 
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/




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