[OSM-dev] Minutely changeset feed

[Alex Barth]

Toby -

The changeset replicator was a result of our OWL related sprint last weekend (I owe a writeup on it where this should have been mentioned, but Sandy jumbled up my weekend). Matt Amos wrote and deployed it - he'll be able to answer your more specific questions better than I so I stop right here.

This replicator is about to be used on the resurrection branch of OWL that pawel is working on: https://github.com/ppawel/openstreetmap-watch-list

It will allow services like OWL to get to meta info on changesets like the comment as the changesets are created without pounding the main OSM API.

Alex

On Nov 2, 2012, at 2:34 AM, Toby Murray <toby.murray at gmail.com> wrote:

> Since I have been playing with changeset metadata[1] a bit, Paul
> Norman recently pointed out to me that there are now minutely diffs of
> changesets available from planet.osm [2]. Would anyone care to share
> some juicy details like where it came from and how it works?
> Apparently it was mentioned in an EWG meeting. I should really check
> one of those out...
> 
> Anyway, some observations/questions:
> 
> I see the state file is in a different format than all the other
> replication state files. Probably not a big deal but is there value in
> consistency?
> 
> Are there any existing tools to use this stream?
> 
> It looks like changesets don't show up until they are closed. This
> makes sense since then you don't have to worry about information
> changing.
> 
> However, what will it do in the edge case where a changeset is closed
> but then reopened? Not possible you say? I once had an upload take
> over an hour to process. It did eventually succeed but the changeset
> was marked as closed in my changeset list for several minutes before
> the upload finished and then it was suddenly open again. I am assuming
> in this case the changeset would show up twice in the minutely diffs
> and cause the INSERT queries of all consumers to explode violently :)
> 
> [1] https://github.com/ToeBee/ChangesetMD
> [2] http://planet.openstreetmap.org/replication/changesets/
> 
> Toby
> 
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Alex Barth
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