GML download slow through postgis compared to local shapefiles

[Patricio Cifuentes Ithal]

> -----Mensaje original-----
> De: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] En
> nombre de Maarten Plieger
> Enviado el: Jueves, 25 de Octubre de 2007 12:57
> Para: MAPSERVER-USERS at LISTS.UMN.EDU
> Asunto: [UMN_MAPSERVER-USERS] GML download slow through postgis
> compared to local shapefiles
> 
> Hello All,
> Currently I am comparing GML download performance through a WFS with
> mapserver. The source data is stored directly on disk in the ESRI shape
> format, and is also available from a postgis database located on the
> same machine. So it is exactly the same data but from different
> sources.
> The shapefiles contain about 90000 polygons per file. I am timing the
> rendering time in WMS and the download speed in WFS.
> WMS rendering time for a shapefile:
>     For the shapefiles on disk:  2.897 seconds
>     From the postgis database: 3.3 seconds.
> (seems ok for both data sources)
> 
> However when I start downloading the data with the WFS in GML2 format:
> For the shapefiles on disk:  8 Seconds
>     66,8 MB in 8 sec
>     8,35 Mb/Sec <== fast
>  From the postgis database: 84 Seconds
>     66.8 MB  in 1 min 24 sec
>     800KB/Sec <== slow
> 
> These are the postgis parameters:
> CONNECTIONTYPE postgis
> CONNECTION "host=localhost dbname=pliegerdatabase user=plieger
> password=* port=5432"
> DATA "the_geom from (select * from vcdtrop) as foo using unique gid
> using SRID=4326"
> 
[Patricio Cifuentes Ithal] 

Hi,
Test with "the_geom from table using SRID=4326"




> Why is downloading GML data through WFS from a postgis database 10
> times
> slower than from locally stored shapefiles?
> Can I do something to improve things? I am using mapserver 5.0.0-rc1 on
> SUSE.
> 
> Thanks in advance,
> Maarten Plieger
> 
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