On 1/28/2017 3:00 PM, Walter Nordmann wrote:
i'm just installing my brand new server to get my applications
(missing boundaries and many more) running again. The server has 2x
960GB SSD and 1x 2TB SATA disk installed.
I'm doing a full planet import using osm2pgsql 0.92. This time i'm
doing the import without flat file, because i would like to use the
nodes in planet_osm_nodes for some new queries.
But: planet_osm_nodes got an actual size of 785 GB, which is much much
more than i exspected. Is that the usual size or may be, i'm doing
something wrong?
With the version of osm2pgsql you have when --extra-attributes is
specified then tags are added to each object with the username, uid,
version, timestamp, and changeset. This adds about 100 bytes per node to
the table, which should add about 350GB. I would expect the size of
planet_osm_nodes with a plain --slim import to be about 175GB, plus indexes.
Does your 785GB figure include indexes? If so, this sounds about right.
The latest versions of osm2pgsql do not have this issue because the node
slim table schema has changed to no longer store tags, because they are
never needed.
It's worth noting that 100 bytes per object for metadata is remarkably
inefficient because it gets stored in a text[] array like
"osm_user,lokejul,osm_uid,2034065,osm_version,11,osm_timestamp,2015-04-12T18:39:22Z,osm_changeset,30169891".
This uses more bytes because it stores "tag" names, and because there
are more efficient ways to store numbers and timestamps than as text.
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