Richard Mann wrote:
I think he was joking about reusing ids (he was illustrating the point
with the sort of daft temporary fix that someone might do ... if they
were daft)
Well someone has set up the system to reuse them !!!!
http://www.openstreetmap.org/browse/node/1/history
THAT is a joke :(
PLEASE can someone disable that corruption before it goes too far?
On Tue, Aug 2, 2011 at 5:35 PM, Lester Caine<les...@lsces.co.uk> wrote:
Rather than comment on the id stability thread, I though it better to turn
the question around ...
In my own data trail, an ID *IS* unique, and is directly linked to the piece
of data it relates to. If I change the data then the version number goes up.
If I delete the data, then the ID number remains since it identifies the
HISTORY relating to that item. The idea that someone is going to 'reuse'
id's because they are no being used raises alarm bells. I thought we had
history relating to every element nowadays, so how do you know what the
history relates to if you reuse the ID? Also the idea of 'renumbering'
everything is equally alarming, given that every old changeset would have to
be updated?
If we are running out of ID's, then a switch to 64 bit is an urgent
requirement simply to prevent the existing data and history trail from being
corrupted.
Now having said all that ... USING the internal ID for external purposes,
while potentially practical, is not the most sensible way forward as has
been highlighted in several ways. I'm probably in agreement on a 'link
server' approach, but I think that there are a number of areas where
additional 'ID's need to be stored in the database and managed in parallel.
Postcodes, bus/tramstop id's, Airport codes, telephone area codes, and so
on. We had a little discussion on parallel databases, and that slots in with
the 'link server', but I think that in order to make ANY parallel database
system work, then the core ID's have to be stable and consistent, even if
they do return 'deleted' ... at which point on needs to be able to ask 'why'
and possibly roll back a change that should not have happened? If a item has
history then it's ID can't be reused.
http://www.openstreetmap.org/browse/node/<xxx>/history simply has to be
consistent? Then what may be missing IS a tag for 'split_from' or
'merged_with' but the linked ID's must also be consistent?
--
Lester Caine - G8HFL
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