[OSM-dev] Minute Diffs Broken

Frederik Ramm frederik at remote.org
Tue May 5 22:53:25 BST 2009


Hi,

Tom Hughes wrote:
>> Perhaps this could be done internally: User uploads new relation; 
>> Rails goes through the elements of that new upload, and checks whether 
>> these elements were already in the previous version. If yes, no 
>> further check is required (because the previous relation is assumed to 
>> have only valid members), so we only need to check those members that 
>> are new.
> 
> Except the whole point is to avoid looking up all the members... Once 
> we've looked them up checking if they're still visible is cheap.

I was trying to say that you don't have to look them up. You get the 
member ids/types of the new relation, remove from that list the member 
ids/types of the old relation, and then look up only the remaining 
members, if any.

Or did you mean that it takes tens of seconds to execute the Rails 
equivalent of "select * from relation_members where id=1234"?

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"




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