[OSM-dev] production site disk use question
Frederik Ramm
frederik at remote.org
Tue Jan 1 20:37:45 GMT 2013
Hi,
On 01.01.2013 18:52, Jeff Meyer wrote:
> So, it seems like I'll need both the history & the
> current tables. In a non-history planet.osm extract,
Yes, if you want any kind of write access *and* read access through the
API (instead of reading with specialised queries) then I guess you'll
need both. The current tables always duplicate stuff that is in the
history tables already, and in theory you could always make queries of
the kind "where version=(select max(version) ...)" against the history
tables to get the same you find in the current tables, but that would be
too expensive.
> should those tables
> be the same in an initial import?
Yes, with the exception that foreign keys contain the version number in
the history tables but not in the current tables (since the current
tables only contain ONE way ID #1234, the current_way_tags can afford to
reference only the way ID, whereas in the history table it must
reference way ID and version).
Bye
Frederik
--
Frederik Ramm ## eMail frederik at remote.org ## N49°00'09" E008°23'33"
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