On 26/01/11 09:09, Daniar Achakeyev wrote:
Hi,
I am new to postgis. I am interesting in bulk loading R-Trees. What kind
of approaches uses postgis for bulk loading: sort based or sort tile
recursive (STR)?
Thanks,
Daniar Achakeyev
Hi Daniar,
PostGIS indices are built using the PostgreSQL GiST API (see
http://www.postgresql.org/docs/9.0/interactive/gist-implementation.html
for the API in use) and these methods are generally called for each item
at a time. Hence there isn't really any support for bulk-loading
information into the R-Tree, although you could conceivably come up with
something that generates the pages within PostgreSQL at a very low level.
There has been some work to show that changing the order in which
geometries are loaded (via a locality-based pre-sort) into the index can
result in better R-Trees and hence quicker build times, but I don't
think anyone is actively working on this.
ATB,
Mark.
--
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
http://www.siriusit.co.uk
t: +44 870 608 0063
Sirius Labs: http://www.siriusit.co.uk/labs
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