[postgis-devel] Caching Double-based Boxes

[Paragon Corporation]

Paul,

Is there a reason why geography should be affected by this too.  On checking
the times on my garden tests, I'm seeing geography being worse as well, but 
it could be because most of the tests aren't testing index usage and are
building geography with geography(geometry..) constructs that they are being
penalized for the construction slow-down of geometry.

See attached. anyrate does seem to come back with the same 10-15% worse
answer though some tests seem to fair a lot better on the dbox side.
haven't looked at those to see what they are or how common of a case they
are.

Thanks,
Regina



> -----Original Message-----
> From: postgis-devel-bounces at postgis.refractions.net 
> [mailto:postgis-devel-bounces at postgis.refractions.net] On 
> Behalf Of Paul Ramsey
> Sent: Saturday, November 26, 2011 4:06 PM
> To: PostGIS Development Discussion
> Subject: Re: [postgis-devel] Caching Double-based Boxes
> 
> Thanks Brian,
> Just taking the three results for each branch and averaging 
> them and comparing seems to show at least a 10% or maybe 
> higher slowdown with the double boxes.
> P.
> 
> On Sat, Nov 26, 2011 at 12:44 PM,  <maplabs at light42.com> wrote:
> > Hi All-
> >
> >   I have devised a second set of tests, based on the first run and 
> > some suggestions. There are three sets of results for each of the 
> > source builds, float bbox and double bbox. The condensed 
> records are here:
> >
> >     
> > 
> http://download.osgeo.org/postgis/postgis_dbl_boxes_test_results22.csv
> >
> > Notes:
> >
> > * there is one test result in one run that was lost..
> > * I have not analyzed these numbers.. I expect people will 
> want to do 
> > that for themselves. Barring an undiscovered problem in the setup, 
> > there are very large differences in run times for the double-boxes 
> > branch, but almost entirely consistant run times for the 
> float-trunk 
> > branch.
> >
> > * The third run in each case was after a database restart, 
> in order, 
> > from top to bottom. The isolated numbers in the columns are 
> 'cold' bbox hits..
> > much much larger than
> > running them a second time, so I noted them as an aside
> >
> >
> > best regards from San Francisco, California
> >
> > Brian Hamlin
> > GeoCal
> > OSGeo California Chapter
> > 415-717-4462 cell
> >
> >
> >
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