[OSM-dev] Osmosis, Changesets, Diffs (replicate) and general questions

[Lars Francke]

Hi!

I'd like to set up a new consistent database of the OSM data for
OSMdoc. I've been out of the loop for a while so I've got a few
questions.

1)
If I understood it correctly there is a new type of diffs - the
minute-replicate - which are guaranteed to contain every change but
they are not guaranteed to be generated exactly once a minute so this
seems to be the way to go if one wants to have the best synchronized
data there is. I also found out that there is an undocumented feature
in osmosis to work with these diffs (--rri and --rrii) just like the
"old" diffs.
Is this correct so far?
Are there any plans to generate such diffs on a hourly or daily basis?

2)
It seems as if none of the diffs contain the changesets. I may have
missed something here but the only way to get these seems to be the
weekly dump of all changesets or by using the API? As I use the
changeset tags for OSMdoc I'd be very interested why this is the case
and if there are any plans to change this.

3)
* My initial import of OSMdoc data is done using a custom program.
* The following data adjustments are done using the diff-files, the
database (in a state as it was _before_ the diff), osmosis and an
osmosis plugin
* The initial import of OSM data is done using osmosis (--write-pgsql)

As the minute-replicate diffs overlap (at least they used to do) the
planet.osm dump it is best (..at least it used to be ;-) ) to create a
"consistent" dump using the planet.osm and gradually applying diffs
(using --apply-change) as there is no harm in applying changes that
are already present in the planet.osm. What is the best way to do
this? I hope I made myself clear, I don't know how to explain it
better.
To put it in other words: When I start using my osmosis plugin to
alter the OSMdoc data using the diffs I need to be sure that both
datasets work on the same data.

4)
What is the order of execution of osmosis tasks?
I'd like to do something like: osmosis --rri ... -p "plugin.class"
--tee-change outputCount=2 --osmdoc-plugin --write-pgsql-change but my
osmdoc-plugin needs to access the data in the db as it was before the
diff (i.e. before the --write-pgsql-change). Is this guaranteed or do
I need to split this in two osmosis runs?

Thanks a lot for bearing with me. I hope someone can answer some of my
questions :)

Cheers,
Lars