On Thu, Mar 22, 2012 at 2:23 PM, David Adler <[email protected]> wrote:
> The PostGIS data store interface allows one to select "Loose bbox" but
> this isn't available for DB2.
>
> The "Loose bbox" can improve query performance by a factor of 2-5 and
> CPU utilization by a factor of 10.
>
> How can this get added?
>
Loose bbox in postgis uses a sql function (st_estimated_extent) that
queries the root
of the spatial index instead of accessing the whole data set:
http://postgis.refractions.net/documentation/manual-1.3/ch06.html
To implement something similar in DB2 I guess you need an equivalent
sql function for DB2 (and then write code to support it)
Cheers
Andrea
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