[OSM-talk] Orphaned Relations

Sarah Hoffmann lonvia at denofr.de
Wed Jul 20 17:56:19 BST 2011


On Tue, Jul 19, 2011 at 03:03:53PM +0200, andrzej zaborowski wrote:
> On 17 July 2011 23:55, Sarah Hoffmann <lonvia at denofr.de> wrote:
> > I recently stumbled upon some empty route relations, so I had a
> > closer look at the OSM planet and found that there are about
> > 10.000 orphaned relations in the database and the number is growing.
> >
> > With orphaned I mean relations that have no members and are not
> > member of any other relation. Some are completely empty but most
> > still have some tags. I have created a list of the relations sorted
> > by last editing user here:
> ...
> >
> > Question remains what to do with the existing orphaned relations.
> > Is there any legimate use for them or would it be save to simply
> > delete them all?
> 
> So I had stumbled on the same fact about a year ago and after some
> discussion on this list I deleted about 8000 empty/orphaned relations.
>  It seems all except a handful of those 8000 relations had indeed been
> left in the not-deleted state by mistake.  There were a couple (<5)
> that had still been referenced from the wiki, rather than from inside
> the database through other relations.  I got a couple of e-mails
> months later asking about those relations and undeleted them, it would
> probably be a good idea to check for references in the wiki beforehand
> this time.  I don't think it makes sense to create such empty
> relations before any members are added to them because it's quite
> likely someone else is going to create a duplicate, but I don't have a
> strong opinion and being in the losing position as an author of an
> automated edit I didn't want to argue with the creators of these
> relations.

I must have missed that discussion. 

So I gather it is pretty pointless to try and fix the database
if new empty relations arrive with a rate of about 30 per day,
time is better spent improving editors and/or creating 
a service where people can find their lost relations again. I'll 
look into it.

A more final solution to the problem would be to reject empty
relations on the API side. But that still requires fixing the editors
first. Maybe something for API 0.7.

Sarah





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