[OSM-dev] History File Formats

Frederik Ramm frederik at remote.org
Wed May 11 17:14:14 BST 2011


On 05/11/11 15:31, Brett Henderson wrote:
> I then used the osc file format to create not only the commonly used
> daily/hourly/minutely replication files, but also a complete dump of
> database history updated daily (stored in one file per day).
> http://planet.openstreetmap.org/history/
> I was slightly surprised then to see the creation of the new full
> history files.

I wasn't sure what these are, and I think I am still confused. What is 
the difference between the daily replication file and the file in 
/history/? Assuming I want to have a local, current full history file, 
how can I use these diffs to amend an existing full file that I have?

> But I do wonder why we've now gone back to a single
> massive file approach which is updated rarely and requires a full
> download each time when the existing files allow incremental download of
> recent changes.

Is it so bad to generate a full history file four times a year? I 
haven't done the maths but I guess that downloading 300 daily diffs and 
applying them to a 300-day old history file will take some time too. 
What happens if users change their account names, or set their "public" 

> It leaves me with a few questions:
>     * Are the Osmosis-based daily full history extracts even used?
>       Should I disable/delete them?

I'm not using them but mainly because I don't know how ;)


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