[OSM-dev] 'My first OSM experiences' - PDA Mapping software and the OSM mobile binary protocol
siliconfiend at gmail.com
Wed Jan 7 22:35:56 GMT 2009
On Wed, Jan 7, 2009 at 2:28 PM, Brett Henderson <brett at bretth.com> wrote:
> Karl Newman wrote:
>> Heh, I was thinking along those lines, too, but I thought I'd wait until
>> your format stabilizes. It would be quite handy to have a random-access data
>> source for Osmosis without requiring a database installation.
> I'm not sure if you realise this but there already is one of those. I
> can't reach the wiki at the moment but the tasks in question are:
> I forget the details of the on-disk format but it's built around the
> osmosis store classes so uses osmosis specific object serialisation.
> The --read-customdb task doesn't actually stream data to downstream tasks,
> it provides the data in the form of a "dataset" object. This can be
> consumed by tasks such as --dataset-dump which will stream from the dataset,
> but it can also be consumed by any task wishing to access data randomly.
> Performance isn't great for large datasets which is why I created the
> pgsql-simple schema. I've never been able to get an on-disk format to scale
> nearly as well as a real database.
> I also wrote a set of tasks based on one the Berkeley DB Java Edition but
> deleted it because performance was even worse.
Actually yes, I was aware of that one, but I recall that you said the
performance was not good and I thought you had removed that one for
performance reasons (I didn't pay close attention; I guess it was the BDB
that you removed instead).
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