[MS4W-Users] slow access to PostGIS layer
giohappy at gmail.com
Thu Jun 28 10:42:14 EST 2012
2012/6/28 Smith, Michael ERDC-RDE-CRREL-NH <Michael.Smith at erdc.dren.mil>
> The biggest impact will be the total amount of data involved. The number
> of vertices you reported earlier seemed quite large for most scales. I'd
> consider doing some generalization for higher zoom levels.
I think I will do that. I didn't notice such an impact within our Linux
The timing is closely related to the number of vertices:
1 polygon (836 vertices):
16 polygons (836 vertices each):
1 polygon (19594 vertices):
16 polygons (19594 vertices each)
Delta time between msPostGISLayerNextShape 0.45s
As you can see, the delta is similar to calling the 16 smaller poligons,
which sum to 13376 vertices.
> Michael Smith
> US Army Corps
> Remote Sensing GIS/Center
> From: "G. Allegri" <giohappy at gmail.com>
> Date: Thursday, June 28, 2012 9:45 AM
> To: Jeff McKenna <jmckenna at gatewaygeomatics.com>
> Cc: "ms4w-users at lists.maptools.org" <ms4w-users at lists.maptools.org>
> Subject: Re: [MS4W-Users] slow access to PostGIS layer
> Resent-From: Michael Smith <michael.smith at usace.army.mil>
> The first important bottleneck is reprojection, obviously.
> Removing the reprojection from 23032 to 900913, the time is dropped from
> 7.2s to 4.6s.
> I go on...
> 2012/6/28 G. Allegri <giohappy at gmail.com>
>> I will go on testing.
>> In the meantime, the same exact shp2img command run on Linux gives much
>> better performances, and OGR outperforms POSTGIS again.
>> POSTGIS: 7.2s
>> OGR: 2.7s
>> POSTGIS: 2.5s
>> OGR: 1.0s
>> 2012/6/28 Jeff McKenna <jmckenna at gatewaygeomatics.com>
>>> And how did another small polygon file do? (it could be a problem with
>>> your one table)
>>> > - load another small polygon shapefile into your PG, then try that
>>> > MapServer
>>> Jeff McKenna
>>> MapServer Consulting and Training Services
>>> MS4W-Users mailing list
>>> MS4W-Users at lists.maptools.org
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