Overpass API developpement

[michael spreng <>]

Hi. Sorry about the last mail reaching the list twice. Here some further
explanations.

On 03/11/15 22:06, mmd wrote:
> Hi,
>
> I'm not sure if I got your scenario right: did you use one of the files
> in http://planet.osm.ch/history/ to populate your database? Which exact
> commands did you use, i.e. how can we reproduce this? I assume you tried
> this on 0.7.52?
I tried it in 0.7.51
The exact command for the history dump was:

osmconvert switzerland-padded-softcut.osh.pbf --out-osc | sudo -u
overpass update_database --db-dir=overpass.osm.ch/db --meta --keep-attic

the command for the hourly diffs was:

zcat $hourly_diff | sudo -u overpass update_database --meta --keep-attic

> If so, you probably ran into the same pitfall as I did last year. To
> make a long story short: full history files cannot be used to populate
> an Overpass DB. I documented all issues I came across on my wiki page:
>
> http://wiki.openstreetmap.org/wiki/User:Mmd/Overpass_API/install/attic
Ah I missed that site. I think someone mentioned it once to me but now
that I wanted to use it in production, I forgot about that site. I
should edit the wiki on Overpass... but it's a daunting task.
> The only way forward is to import an old planet file without history (or
> in your case an older extract) and apply minutely diffs on top of it.
>
> I don't know how well (if at all?) attic works in the context of
> extracts, especially as some objects may get moved outside the extract
> bounding box from time to time. Unfortunately, there's very little
> documentation and experience available on this topic.
>
Then it's good that we run an instance of an extract, just reminds me
that I should document what I did in the end.

Now I'm a bit confused about mmd and Rolands versions of how it could
work with a history dump. On the mmd Wiki site --flush-size=8 is
suggested. Roland suggests --flush-size=0. Is this equivalent as no
element will be smaller than 8 (presumably bytes?)?

Thank you Roland and mmd for the help

Michael