[OSM-dev] Growth of on-disk size of OSM database

[Thomas Petazzoni]

Hi Matt, Hi Frederik,

Following your respective talks at SOTM, we (MapOSMatic) have a question
regarding the growth of the on-disk size of the OSM world database.

We've done an initial import of this database in ~october 2009, and
since then, we've used daily diffs to keep this database up to date. As
of today, our PostgreSQL database takes 174 GB. However, during a
discussion at SOTM, Frederik told us that the size of the world
database resulting from a brand-new import would only be 120-130 GB.
This seems to mean that using the daily diffs does not produce the same
result as making a full import of the database. Is this true ?

Matt, during our talk, you answered a question from the audience asking
whether using minutely diffs over a long period of time would not be a
problem compared to doing regular full imports of the database. Is
there a major difference in how minutely diffs and daily diffs are
handled that would explain why using daily diffs over a long period of
time does not work and why it would work with minutely diffs ?

Thanks for your insights,

Thomas, for the MapOSMatic team
-- 
Thomas Petazzoni                         http://thomas.enix.org
MapOSMatic				 http://www.maposmatic.org
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