[postgis-devel] Caching Double-based Boxes

[Paul Ramsey]

Yes, there is a reason: both geometry and geography share the same
serialization.

On Sun, Nov 27, 2011 at 2:24 PM, Paragon Corporation <lr at pcorp.us> wrote:
>
> 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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