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"
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
